|
|
Title:
Treatment and inhibition of ocular infections and wounds by CAP37 and
CAP37 peptides
United States Patent: 7,354,900
Issued: April 8, 2008
Inventors: Pereira; Heloise
Anne (Edmond, OK), Chodosh; James (Edmond, OK), Callegan; Michelle C.
(Edmond, OK)
Assignee: The Board of
Regents of the University of Oklahoma (Norman, OK)
Appl. No.: 10/423,311
Filed: April 25, 2003
|
|
|
Woodbury College's
Master of Science in Law
|
Abstract
A method for treating ocular conditions
such as bacterial keratitis, bacterial conjunctivitis, corneal ulcers and
wounds, endophthalmitis, and blebitis in mammals, by using a native,
synthetic, or recombinant CAP37, or effective peptide portions thereof
including CAP37 peptides 20-44, 23-42, 102-122, and 120-146 and
monocysteine derivatives of peptides 20-44 and 23-42. The CAP37, peptides,
and peptide derivatives can also be used to store, clean, sterilize, or
coat contact lenses, and may be used in media for storing mammalian
corneal transplants.
Description of the
Invention
BACKGROUND
Ocular infections such as bacterial keratitis are serious clinical
problems. Bacterial keratitis, for example, is a component of many ocular
infections, especially among those who have sustained penetrating corneal
injuries, used extended-wear contact lenses, undergone incisional
refractive surgery, or are immunocompromised. Bacterial keratitis is an
important cause of visual morbidity. Contact lens wearers are most at
risk. More recently, the use of refractive correction in the form of
incisional and laser surgery has emerged as a new cause of bacterial
keratitis (1-4). Loss of vision and permanent scarring are commonly due to
toxic bacterial products and the host inflammatory response to wounding
and infection. Common causative organisms are the Gram positive bacteria
Staphylococcus aureus and the Gram negative bacterium Pseudomonas
aeruginosa (5-7). The bacterial products and toxins and host inflammatory
reaction stimulated in response to wounding and infection often leads to
extensive tissue damage with permanent scarring and irreversible loss of
vision (1).
Current treatments include the use of broad spectrum antibiotics. Topical
antibiotic drops are the preferred treatment for corneal and conjunctival
infections. Intravitreal antibiotics are preferred for endophthalmitis and
parenteral antibiotics are recommended for deep infections.
The diagnosis and treatment of bacterial keratitis remains controversial.
A combination of a fortified topical cephalosporin and a fortified topical
aminoglycoside were once the first line of therapy. However, recently this
therapy has been replaced by fluoroquinolones such as ciprofloxacin and
oflaxacin for topical ophthalmic therapy. However, the emergence of
methicillin-resistant organisms has reduced the effectiveness of these
antibiotics. Thus the choice of initial empirical therapy is
controversial. Clearly, there is a crisis situation developing with
organisms that cause ocular infections which are resistant to antibiotics.
Because early treatment of the infection is important to prevent loss of
vision, treatment is generally started before the specific identity of the
causative organism and its sensitivity are known. Therefore, a broad
spectrum antibiotic is generally used initially. Once the culture results
are known the treatment is best modified to a single drug to cover the
infectious organisms. It is important that the specific antibiotic have as
narrow a spectrum as possible, since broad spectrum agents could
unnecessarily alter the normal flora allowing super infection from
resistant or nonsusceptible organisms.
Steroid treatment has also been used in conjunction with antibiotics in
the hope that it will limit the inflammatory process of the host, however
this course of treatment requires careful monitoring.
Almost all topical ophthalmic antibiotics can cause local irritation and
allergic reactions. Treatment for severe bacterial keratitis (bacterial
corneal ulcer), regardless of the identity of the antimicrobial agent
used, typically consists of instillation of drug every 15-30 minutes
around the clock for the first 2-3 days. The dosing interval is then
gradually increased to every four hours and continued for an additional 14
days. Topical drops are preferred for corneal and conjunctival infections.
The agent should be bactericidal rather than bacteriostatic.
The cornea is normally considered a "privileged" site because of its
avascularity and lack of lymphatic vessels (8-10). Antigens, cytokines,
inflammatory mediators and leukocytes that enter into the cornea must do
so from the limbic and/or ciliary body vessels. Inflammatory cytokines
and/or chemotactic gradients that are elicited locally by corneal cells
could therefore profoundly affect the emigration of leukocytes from the
limbic and ciliary circulation to the cornea.
Extravasation of leukocytes from the circulation into tissue sites is an
integral feature of the host response to injury and inflammation. By
virtue of their ability to engulf and destroy bacteria, eliminate toxins
and secrete numerous soluble mediators, leukocytes are capable of
restricting and limiting the spread of infection. Neutrophils (PMNs) are
the predominant cell type in the early phases of inflammation and are soon
followed by a second wave of cells composed mainly of monocytes and
lymphocytes. Irreversible damage to the eye can occur in cases of
fulminant inflammation. Clearly the desirable outcome is one in which the
immune system can control the infection resulting in re-epithelialization
and healing with minimum damage to vision.
The identification of a corneal derived chemotaxin or inflammatory
mediator could be of extreme importance in our understanding of the
mechanisms that regulate leukocyte migration, epithelial-leukocyte
interaction, corneal inflammation and healing and in identifying methods
of treatment of corneal damage related to infection, inflammation and
physical wounding.
SUMMARY OF THE INVENTION
Pseudomonas aeruginosa is frequently associated with infection following
use of extended-wear contact lenses. The most common organism associated
with corneal infection in patients who do not wear contact lenses is
Staphylococcus aureus. CAP37 is important in the recruitment of leukocytes
from the circulation in the limbus of the eye to the avascular cornea.
CAP37 proteins and peptides derived therefrom can be used as a
topical/oral/intravenous/intravitreal antibiotic for the treatment of
ocular bacterial infections in mammals including humans, primates,
rabbits, livestock animals and ungulates, for example. CAP37 and CAP37
peptides can also be used to promote healing of corneal wounds and ulcers
that may not have an infective component, such as those due to injury by
foreign objects or trauma. CAP37 and CAP37 peptides can also be used to
treat contact lenses, to sterilize the lenses and inhibit infections
caused by bacteria on the lenses. Mammalian corneal transplants can also
be stored in media containing CAP37 and/or CAP37 peptides as described
herein.
Corneal wound healing consists of three interrelated processes, including
corneal epithelial cell proliferation, corneal epithelial cell migration
and upregulation of adhesion molecules that are capable of binding to
extracellular matrix proteins forming attachments and adhesion and thereby
aiding healing. As shown herein, CAP37 promotes corneal epithelial cell
proliferation, and migration. Also shown is that CAP37 upregulates corneal
epithelial cell adhesion molecules including intercellular adhesion
molecule-1 (ICAM-1) and platelet-endothelial cell adhesion molecule-1
(PECAM-1). Both ICAM-1 and PECAM-1 are important in leukocyte-epithelial
interactions. Importantly CAP37 upregulates .alpha.-3 (CD49c) and .beta.-1
(CD29) integrin molecules. .alpha.-3 .beta.-1 integrin molecules are
critical for binding of the corneal epithelial cell to laminin-5 and
fibronectin two important constituents in the basement membrane of the
cornea. Taken together these studies indicate that CAP37 is involved in
the promotion of corneal epithelial wound healing.
DETAILED DESCRIPTION OF THE INVENTION
CAP37 (Cationic Antimicrobial Protein of M.sub.r 37 kDa) is an
inflammatory mediator which plays an important role in host defense and
inflammation in the systemic circulation (11-15). PMN-CAP37 (SEQ ID NO:1)
is constitutively expressed in the granules of human polymorphonuclear
neutrophils (PMNs) and in the .alpha. granules of platelets (16-17), and
due to its strong antibiotic activity was viewed as part of the
oxygen-independent killing mechanism of the PMNs (18-20). The native
protein (PMN-CAP37) is particularly potent against the Gram negative
bacteria including Escherichia coli, Salmonella typhimurium and
Pseudomonas aeruginosa (18-20). Peptides based on the native CAP37
sequence have demonstrated antibiotic activity against the Gram positive
bacteria, Enterococcus faecalis and Staphylococcus aureus (11). In
addition to its effects on bacteria, CAP37 has many important functional
effects on mammalian cells. CAP37 exerts powerful chemotactic activity for
monocytes (13) and regulates endothelial cell functions, such as
stimulating protein kinase C (12).
CAP37 proteins and peptides derived therefrom can be used as a
topical/oral/intravenous/intravitreal antibiotic for the treatment of
ocular bacterial infections in mammals including humans, primates,
rabbits, livestock animals and ungulates, for example. CAP37 and CAP37
peptides described herein can also be used to promote healing of corneal
wounds and ulcers that may not have an infective component, such as those
due to injury by foreign objects or trauma. CAP37 and CAP37 peptides
described herein can also be used to treat contact lenses, to sterilize
the lenses and inhibit infections caused by bacteria on the lenses.
Mammalian corneal transplants can also be stored in media containing CAP37
and/or CAP37 peptides as described herein.
The present invention contemplates these treatments using a CAP37 protein
(native, synthetic, or recombinant) such as a CAP37 shown in SEQ ID NO:1,
or SEQ ID NO:2. The present invention also contemplates the use of CAP37
peptides including CAP37 peptide 20-44 (SEQ ID NO: 3), CAP37 peptide 23-42
(SEQ ID NO:4), CAP37 peptide 102-122 (SEQ ID NO:5), CAP37 peptide 120-146
(SEQ ID NO:6), and monocysteine derivatives of CAP37 peptide 23-42 and
CAP37 peptide 20-44, (including peptides of SEQ ID NO:7 and SEQ ID NO:8)
having the formula, for example:
R-H-X.sub.1-X.sub.2-X.sub.3-X.sub.4-X.sub.5-X.sub.6-X.sub.7-H-X.sub.8-R-X-
.sub.9-X.sub.10-M-X.sub.11-X.sub.12-X.sub.13-X.sub.14-X.sub.15 wherein
X.sub.1 and X.sub.9 are phenylalanine and/or tyrosine; X.sub.2 and
X.sub.15 are cysteine, serine, and/or threonine; X.sub.3 and X.sub.4 are
glycine and/or alanine; X.sub.5-X.sub.8, X.sub.10, X.sub.12 and X.sub.13
are alanine, leucine, isoleucine and/or valine; X.sub.11 is serine and/or
threonine; X.sub.14 is serine, threonine, histidine, arginine or lysine; R
is arginine; H is histidine; M is methionine; and with the proviso that
one of X.sub.2 and X.sub.15 is cysteine and one of X.sub.2 and X.sub.15 is
serine or threonine.
To investigate the biological significance of CAP37 in corneal infection,
inflammation and healing, we used a well characterized in vivo rabbit
model of S. aureus keratitis (21,22). An unexpected and surprising
observation was the expression of a CAP37 protein in corneal epithelial
cells, stromal keratocytes, ciliary epithelium, related limbus and ciliary
vascular endothelium and bulbar conjunctiva. Particularly striking was the
extremely strong staining for CAP37 in corneal epithelium (23). The in
vivo studies outlined here demonstrate the kinetics of expression of CAP37
in extra-neutrophilic sites including corneal epithelium and stromal
keratocytes. These findings were further dissected using in vitro studies
in which human corneal epithelial cells and stromal keratocytes were used
to determine the mechanism of induction of CAP37 in these cells. Molecular
cloning of corneal epithelial-derived CAP37 (EPI-CAP37-SEQ ID NO:2) was
undertaken to confirm our immunocytochemical analysis that the corneal
epithelial-derived protein was unequivocally CAP37. The results of the
present work indicate that CAP37 has far wider ranging effects on the
inflammatory process than acting solely as an antibiotic and plays a
significant role in the sequence of events involved in leukocyte
emigration and epithelial-leukocyte interactions in the inflamed cornea
following infection.
Corneal epithelial wound healing has been described as comprising three
sequential events: cell migration, cell proliferation and cell adhesion
(24-26). We addressed the effect of CAP37 in vitro on these three critical
elements of wound healing. Corneal epithelial cell proliferation was
assessed using the CyQuant proliferation assay. Cell migration was
determined by measuring chemotaxis using the modified Boyden chemotaxis
chamber assay. Migration of leukocytes from the vasculature is dependent
on the upregulation of adhesion molecules, therefore we measured the
effect of CAP37 on upregulation of E-selectin, intercellular adhesion
molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and
platelet endothelial cell adhesion molecule-1 (PECAM-1) on human corneal
epithelial cells (HCEC). Since attachment of the newly formed epithelium
to the extracellular matrix is essential for completing the healing
process we measured adhesion molecules such as .beta.1, .beta.2, .beta.3,
.beta.4, .alpha.v, .alpha.1, .alpha.2, .alpha.3 and .alpha.4 that are
capable of binding to fibronectin, laminin and other extracellular matrix
proteins (27) contributing to the formation of attachments and adhesion,
thereby aiding the healing process.
Corneal Expression of CAP37
Methods
In Vivo Model of Staphylococcus aureus Keratitis
A rabbit model of S. aureus keratitis was used to determine the
localization of CAP37 in the eye in response to infection. The model is
well established and the methodology published previously (21-22).
Maintenance of animals and all in vivo experimentation was performed
according to institutional guidelines and the Association of Research in
Vision and Ophthalmology resolution on the use of animals in research.
Briefly, New Zealand white rabbits (2.0-3.0 kg) were injected
intrastromally with approximately 100 cfu of log phase S. aureus (RN6390 a
wild-type strain generously provided by Dr. Ambrose Cheung, Rockefeller
University, New York, N.Y.) (28). The contralateral eye was injected
intrastromally with either phosphate buffered saline (PBS, 0.01 M, pH 7.4
containing 0.15 M NaCl; sham control) or was left undisturbed (absolute
control). The rabbit eyes were assessed every 5 hr post infection by slit
lamp examination (TOPCON BIOMICROSCOPE SL-5D, Kogaku Kikai K.K., Tokyo,
Japan) (21, 22, 29). The course and severity of S. aureus keratitis caused
by strain RN6390 in these experiments was found to be similar to our
previous reports (21, 22, 29). Eyes were enucleated at 5, 10, 15, 20 and
25 hr post infection and processed for histologic analysis by fixing in
10% formalin for 24 hours. Tissue embedding, processing and sectioning was
performed according to standard histologic techniques (Dean McGee Eye
Institute, Histology Service Facility, Oklahoma City, Okla.).
Cell Culture
Immortalized human corneal epithelial cells (HCEC) provided by Dr.
Araki-Sasaki, Suita, Japan were maintained as previously published (30).
Briefly, HCEC were cultured in defined keratinocyte serum-free medium (GIBCO
BRL, Grand Island, N.Y.) containing 1% penicillin-streptomycin (GIBCO BRL).
Human stromal keratocytes were derived from donor corneas (North Florida
Lions Eye Bank, Jacksonville Fla.) and cultured in Dulbecco's modified
Eagle's medium (DMEM, Mediatech, Herndon, Va.) containing 10% fetal bovine
serum (FBS, HYCLONE LABORATORIES, Logan, Utah) and 1%
penicillin-streptomycin (GIBCO BRL) according to our previous methods
(31). Media changes were made every two to three days, and cells were
subcultured (0.25% trypsin-1 mM EDTA at 37.degree. C. for 5 minutes, GIBCO
BRL) when they reached 70% confluence at a split ratio of 1:3. For
measurement of cell adhesion molecules, the cells were detached using 5 mM
EDTA alone (37.degree. C. for 10 min). Cells were transferred to serum
free basic medium overnight before the start of each experiment.
Recombinant CAP37
Functionally active recombinant CAP37 (rCAP37) was produced using a
RSV-PL4 expression system in human 293 cells (32). The recombinant protein
was characterized as to amino acid sequence, SDS polyacrylamide gel
electrophoresis and western blots and was shown to be identical to native
PMN-derived CAP37. All preparations of rCAP37 comprised <0.1 endotoxin
units/pg as determined by the limulus amebocyte lysate assay (QCL 100,
WHITTAKER BIOPRODUCTS, Walkersville, Md.) performed exactly according to
the manufacturer's instructions.
Immunohistochemistry
The immunohistochemical analysis performed on paraffin-embedded formalin-fixed
rabbit eyes was according to previously published methods (13, 33). We
used a previously characterized monospecific mouse anti-CAP37 antiserum
(13) and the VECTASTAIN.TM. avidin-biotin-complex (ABC) Elite technique
(VECTOR LABORATORIES, Burlingame, Calif.) to detect CAP37. Briefly, 5 .mu.m
sections were cut along the optical axis and following the various
blocking steps (33) were incubated in the primary antibody (mouse
anti-human CAP37 at 1: 1000 dilution in PBS containing 0.1% normal goat
serum and 0.1% bovine serum albumin) for 60 min at room temperature.
Following three washes in buffer the slides were incubated for 30 minutes
in the secondary antibody (biotinylated goat anti-mouse IgG, VECTASTAIN
ABC Elite, VECTOR LABORATORIES) and then processed exactly as described in
our previous publication (33). In order to determine non-specific
staining, negative controls without the primary antibody, normal mouse
serum, and immunoadsorbed anti-CAP37 antiserum were incorporated in each
experiment. Tissues were viewed under an Olympus BH-2 (Hitschfel
Instruments, Inc, Lake Success, N.Y.) microscope and photographs taken
using an Olympus C-35AD4 camera.
For immunocytochemical analysis of HCEC and stromal keratocytes in
culture, the cells were cultured on coverslips (CORNING COSTAR, Acton,
Mass.) placed within 24-well tissue culture plates (CORNING COSTAR) until
they reached 70% confluence and immunostained for CAP37 as described above
except for the following changes. Cells were fixed in formol-acetone, pH
7.4 for 60 s at 4.degree. C. (13) and were stained using the mouse
anti-human CAP37 antiserum (1:500 dilution).
In Vitro Induction of CAP37 in HCEC and Keratocytes
To determine if pro-inflammatory cytokines could induce CAP37 in HCEC and
keratocytes we treated these cell cultures with TNF-.alpha. (0-10 ng/ml,
Boehringer-Mannheim, Indianapolis, Ind.) and IL-1.beta. (0-20 ng/ml,
ENDOGEN, Woburn, Mass.) for 0-24 hr and assayed the cells
immunocytochemically for the presence of CAP37 protein as described above.
Untreated cell cultures were included for each test sample. In addition to
protein detection, upregulation of CAP37 mRNA in response to TNF-.alpha.
and IL-1.beta. was measured by RT-PCR as described below.
RT-PCR
Cultured HCEC were treated with 5 ng/ml TNF-.alpha. and 10 ng/ml
IL-1.beta. for 0-8 hr at 37.degree. C. Total cellular RNA was isolated
from untreated and treated HCEC according to vendor specifications (TRIzol.TM.,
Gibco BRL). After reverse-transcription of 5 .mu.g of total RNA by random
oligonucelotide priming (hexanucleotide mix, BOEHRINGER-MANNHEIM, GmbH,
Germany), the resulting single stranded cDNA was amplified by PCR (PERKIN
ELMER 2400 thermocycler, Norwalk, Conn.) using CAP37 specific primers (CAGAATCAAGGCAGGCACTTCTGC
(SEQ ID NO:9) and GAGAACACCATCGATCGAGTCTCG (SEQ ID NO:10)) designed for a
597 bp internal fragment of HL60-CAP37 (34). The reaction conditions for
reverse transcription were 80 units of RNAse inhibitor (SIGMA), 8 .mu.l of
5.times. strand buffer, 2 .mu.l of random hexanucleotide mix, 1 mM dNTPs (GIBCO
BRL), 10 mM DTT (GIBCO BRL), and 400 units of M-MLV RT (GIBCO BRL) in a
total volume of 100 .mu.l. The reaction mix was incubated at 37.degree. C.
for 50 min followed by incubation at 70.degree. C. for 15 min. The PCR mix
(1.5 mM MgCl.sub.2, 0.2 mM dNTPs, 1.26 .mu.M of each primer and 1 unit Taq
polymerase, GIBCO BRL) was amplified for 30 cycles. Amplified DNA
fragments were separated by electrophoresis on a 1% agarose gel and
visualized by exposure to UV after ethidium bromide (0.5 .mu.g/ml)
staining. To assess the integrity of the cDNA, primers for human .beta.-actin
were used.
Molecular Cloning and Sequencing of HCEC CAP37
The cDNA products from the above RT-PCR were excised from the agarose gel
and purified with the GENE CLEAN II KIT (BIO 101, Vista Cailf.) and then
cloned using the TA CLONING KIT (INVITROGEN, Carlsbad, Calif.) according
to the manufacturer's instructions. Ten white transformants from each
treatment were chosen for plasmid DNA isolation and purification (WIZARD
PLUS SV miniprep DNA purification system, Promega, Madison Wis.). Plasmids
were sequenced in both forward and reverse directions using the T7 and M13
reverse primers from 6 different clones from three independent clonings.
The resulting sequences were aligned using Pole Bio-Informatique Lyonnais,
Network Protein sequence @nalysis (35) for DNA and the consensus sequence
compared against the HL-60 CAP37 cDNA sequence (34).
Flow Cytometry
Flow cytometry was used to assess the upregulation of ICAM-1 and VCAM-1 on
HCEC in response to CAP37 treatment. HCEC were cultured as described above
and treated with CAP37 (0-2000 ng/ml) for 0, 2, 6, 24, 48 and 72 hr. A
corresponding culture was left untreated at each time point. Following
treatment with CAP37, cells were detached with 5 mM EDTA (pH 7.4, Fisher
Scientific), washed twice in PBS and fixed with 0.125% paraformaldehyde
(J. T. Baker, Phillipsburg, N.J.) overnight at 4.degree. C. The cells were
washed in PBS and then incubated in 0.5% normal goat serum and 0.5% BSA in
PBS for 30 min to block non-specific binding sites. For determination of
ICAM-1 expression, cells were incubated in the primary antibody (FITC-labeled
mouse anti-human ICAM-1, BIOSOURCE, Camarillo, Calif.) at 10.sup.6
cells/10 .mu.l at 4.degree. C. for 1 hr. Cells were washed in PBS and
analyzed by flow cytometry (FACSTAR, BECTON DICKINSON, San Jose, Calif.).
For detection of VCAM-1 expression, cells were incubated with unlabeled
primary antibody (monoclonal mouse anti human VCAM-1, ENDOGEN, Woburn,
Mass. at 2 .mu.g/10.sup.6 cells) followed by FITC-labeled goat anti-mouse
IgG (PHARMINGEN, San Diego, Calif.) at 5 .mu.g/10.sup.6 cells and
incubated at 4.degree. C. for 30 min. The isotype control for these
studies was FITC-labeled mouse isotype IgG.sub.1 (PHARMINGEN). The
positive control used in these studies was TNF-.alpha. (5 ng/ml). At least
ten thousand cells were analyzed for each sample.
Statistical Analysis
Data from the adhesion molecule studies are presented as mean.+-.SE.
Groups were compared by unpaired student's t-test followed by ANOVA.
P<0.05 was considered significant.
Results
In Vivo Expression of CAP37 in S. aureus Keratitis Model
Immunohistochemical analysis was performed on tissue sections obtained
from eyes at 5, 10, 15, 20 and 25 hr post injection of S. aureus. The
initial detection of CAP37 was made in the limbal epithelium and to a
lesser extent in the corneal epithelium at 5 hr (FIG. 1a, see Original Patent).
Staining for CAP37 was not observed in sham-injected eyes at 5 hr post
infection (FIG. 1b, see Original Patent) or at the later time points (not
shown). By 10 hr post infection, strong staining for CAP37 was
demonstrated in the corneal epithelium (FIG. 1c, see Original Patent),
ciliary epithelium, related limbus and ciliary vascular endothelium (FIG.
1d, see Original Patent), and bulbar conjunctiva in rabbits injected with
S. aureus. Staining for CAP37 was not observed in sections stained with
normal mouse serum (FIG. 1e, see Original Patent) or with antiserum
immunoadsorbed with CAP37 (FIG. 1f, see Original Patent), see Original Patent.
The antibody control in FIGS. 1e and 1f indicate the specificity of the
reaction for CAP37. No PMN or other leukocytic infiltration was observed
in the cornea at the 10 hr time point. However, a few PMN were seen in the
bulbar conjunctiva and the corneal limbus. The strong staining for CAP37
in the corneal epithelium persisted up to 15 hr (FIG. 1g, see Original Patent)
and began to wane by 20 hr (FIG. 1h, see Original Patent). Staining for
CAP37 in stromal keratocytes was more marked at the 15 hr time point than
at the 10 hr time point. An important observation in this in vivo model
was that CAP37 induction in vivo was observed before leukocyte
infiltration, which in our studies occurred at 15 hr post infection (FIG.
1g, see Original Patent). Neutrophils were first seen in the stroma at
approximately 15 hr post injection of the pathogen, and then began to
accumulate at the base of the epithelial layer between 20 and 25 hr post
infection (FIG. 1h, see Original Patent). Obvious stromal edema and severe
anterior chamber inflammatory reaction were also readily observed at the
later time points. With time, the inflammatory reaction became more
severe; clumps of bacteria were evident within the stroma but the levels
of CAP37 in the corneal epithelium and stromal keratocytes diminished. It
is important to note that PMN continued to stain for CAP37 throughout all
the time points (FIG. 1h), even though epithelial CAP37 was reduced or
could no longer be detected.
In Vitro Expression of CAP37 in Human Corneal Epithelial Cells and
Keratocytes
Since CAP37 was detected in the corneal epithelium and stromal keratocytes
in vivo in response to the intrastromal Gram-positive infection but was
not present in normal, uninfected eyes, the possibility that CAP37 was
induced in response to inflammatory mediators and/or cytokines generated
as part of the host's defense response to the infection was studied. Two
proinflammatory cytokines, TNF-.alpha. and IL-1.beta., are known to be
present during the acute stages of a wide range of inflammatory situations
(36-39), and have been implicated in gene expression of other
chemoattractants such as IL-8 (40-41). Using immunocytochemistry and
RT-PCR we explored the possibility that they might regulate CAP37
expression in HCEC and keratocytes. The immunocytochemical data presented
in FIG. 2 (see Original Patent) demonstrate that CAP37 protein is induced
in HCEC in response to TNF-.alpha. (FIG. 2a, see Original Patent) and
IL-1.beta. (FIG. 2b, see Original Patent). Detection of CAP37 protein was
observed as early as 60 min in the TNF-.alpha. treated cells and appeared
maximum at 24 hr. Expression of CAP37 in response to IL-1.beta. was
observed at a later time point (4 hr) and like TNF-.alpha. appeared to
have its maximum effect at 24 hr. There was no constitutive expression of
CAP37 protein in untreated HCEC (FIG. 2c, see Original Patent). Antibody
controls using immunoadsorbed anti-CAP37 antiserum showed no staining,
indicating the specificity of this reaction (FIG. 2d). Stromal keratocytes
treated with TNF-.alpha. (FIG. 2e, see Original Patent) and IL-1.beta.
(not shown) showed the induction of CAP37 protein. Once again there was no
constitutive expression of CAP37 in these cells as indicated by a lack of
staining with the anti-CAP37 antiserum in the untreated cell cultures (not
shown). The specificity of this reaction was demonstrated by the lack of
staining with the immunoabsorbed antibody control (FIG. 2f, see Original Patent).
We corroborated the immunocytochemical data above using RT-PCR. Human
corneal epithelial cells treated with TNF-.alpha. (FIG. 3a, see Original Patent)
and IL-1.beta. (FIG. 3b, see Original Patent) showed a time-dependent
expression of CAP37 mRNA. Untreated HCEC do not express CAP37 mRNA.
However, on treatment with the proinflammatory cytokine, TNF-.alpha., HCEC
express CAP37 mRNA as early as 15 minutes. These levels are maximum
between 30 min and 2 hr, and reduced by 4 hr. IL-1 .beta. also induced
CAP37 mRNA in HCEC. However as demonstrated in FIG. 3b, the initial
expression of CAP37 mRNA is delayed and is not detected until 1 hr post
stimulation. Furthermore, the effect is more sustained than with TNF-.alpha.,
as the message can be detected even at 6 hr. These findings corroborate
our immunocytochemical data in which TNF-.alpha. induced protein at an
earlier time point and that the more intense staining of CAP37 was
obtained in response to IL-1.beta..
Molecular Cloning of Human Corneal Epithelial Cell CAP37 (EPI-CAP37)
To determine whether EPI-CAP37 (SEQ ID NO:2) was similar to PMN-CAP37 (SEQ
ID NO:1) we undertook the cloning of HCEC-CAP37. Total cellular RNA was
isolated from HCEC treated with TNF-.alpha. for 2 hr and cDNA synthesis
performed according to the methodology described above. RT-PCR was used to
amplify the CAP37 gene from HCEC using the pair of oligonucleotide primers
as described in the methods and based on a previously published cDNA
sequence of CAP37 (34). EPI-CAP37 has the same sequence as residues 20-218
of PMN-CAP37 (SEQ ID NO: 1) except for amino acid residue at position 113
of EPI-CAP37 (SEQ ID NO:2), wherein a histidine residue consistently
replaced the arginine residue found at the corresponding position in
PMN-CAP37 (i.e., residue 132 of SEQ ID NO:1).
Upregulation of ICAM-1 on Cultured HCEC
In vitro studies were undertaken to investigate the effect of CAP37 on the
upregulation of ICAM-1, on HCEC. Cells were treated with CAP37 (0-2000 ng/ml)
for 0-72 hr and levels of ICAM-1 measured using flow cytometry. ICAM-1 was
upregulated by CAP37 in a dose-dependent fashion, with maximum
upregulation obtained with 1000-2000 ng/ml of CAP37 (FIG. 4a, see Original Patent).
These levels were comparable to those obtained with the positive control
TNF-.alpha. (5 ng/ml). Lower, yet significant levels of ICAM-1 were
obtained with CAP37 at concentrations between 10 and 500 ng/ml. Kinetic
studies (FIG. 4b(see Original Patent)) indicated that HCEC did not
constitutively express ICAM-1 and that no upregulation of ICAM-1 could be
detected by flow cytometry at the early time point of 2 hr. However by 6
hr, significant upregulation of ICAM-1 was observed. The levels declined
by 24 hr, but were still above the untreated levels.
As noted previously, extravasation of leukocytes from the circulation into
tissue sites is an integral feature of the host response to injury and
inflammation (42). By virtue of their ability to engulf and destroy
bacteria, eliminate toxins and secrete numerous soluble mediators,
leukocytes are capable of restricting and limiting the spread of
infection. In the acute stages of most infections, the predominant cell
type is the PMN (42, 43). This observation held true in our in vivo rabbit
model of S. aureus keratitis, where the primary leukocyte observed in the
initial 25 hr period following infection was the PMN. The rabbit bacterial
keratitis model indicated the expected expression of CAP37 in the granules
of migrating PMN. However, a surprising and unexpected observation was the
expression of CAP37 in corneal epithelial cells, stromal keratocytes,
ciliary epithelium, related limbus and ciliary vascular endothelium and
bulbar conjunctiva. Particularly striking was the extremely strong
staining for CAP37 in corneal epithelium at 10 hr post infection. The
induction of CAP37 in the cornea occurred prior to the emigration of PMN,
which in this model occurred approximately 15 hr post infection. The path
of migration of PMN appeared to be from ciliary and limbal vessels through
the stroma to the basal aspects of the epithelial layer, where large
numbers of PMN were seen to accumulate.
Clearly, as indicated by the present results, extra-neutrophilic CAP37 is
induced in response to infection or an inflammatory stimulus, since
sham-injected animals do not show staining for CAP37. These are
significant findings, since the extra-neutrophilic localization of CAP37
in ocular tissue in response to infection has not been reported
previously. Our data indicate that the source of CAP37 in the corneal
epithelium is endogenous during the early stages of infection. This is
based on our unequivocal observations that corneal CAP37 is seen in the
absence of and prior to PMN extravasation. Thus the staining observed in
the epithelium could not be due to exogenously released CAP37 from PMN.
Our in vitro studies depicted in FIGS. 2 and 3 (see Original Patent)
support the concept that CAP37 can be induced in any ocular infection in
which TNF-.alpha. and IL-1.beta. are generated.
Our in vitro studies show that the pro-inflammatory mediators TNF-.alpha.
and IL-1.beta. regulate CAP37 expression in corneal epithelial cells and
stromal keratocytes in a time- and dose-dependent fashion. Untreated cells
did not display CAP37 message or protein, indicating that it is not
constitutively expressed in either of these cells. This is the first
demonstration of the expression of a monocyte chemoattractant in HCEC in
response to cytokines. The induction of monocyte chemotactic protein-1
(MCP-1), RANTES (44), and GRO.alpha. (45), members of the C-C chemokine
family with chemotactic effects on monocytes has been demonstrated in
stromal keratocytes but not in HCEC. On the other hand, expression of
C-X-C chemoattractants such as IL-8 with potent effect on PMN migration
can be induced in HCEC (40) and stromal keratocytes (31). These studies
demonstrate a novel localization of the inflammatory mediator CAP37 and
indicate that these new properties contribute to its role in host defense
in ocular inflammation.
Modulation of Corneal Epithelial Cell Functions by CAP37
Methods
Cell Culture
Immortalized human corneal epithelial cells (HCECs,) provided by K.
Araki-Sasaki, (Suita, Japan) (30) were grown and maintained in defined
keratinocyte-serum free media (GIBCO BRL, Grand Island, N.Y.) containing
1% penicillin-streptomycin (GIBCO BRL) as described previously (31). Media
changes were made every two to three days and cells were subcultured
(0.25% trypsin-1 mM EDTA at 37.degree. C. for 5 minutes, GIBCO BRL) when
they reached 70% confluence at a split ratio of 1:3.
Recombinant CAP37
Functionally active recombinant CAP37 (rCAP37) was produced and
characterized as described above.
Cell Proliferation
Human corneal epithelial cells were seeded onto 48 well tissue culture
plates (7.5.times.10.sup.3 cells/well, FALCON, Franklin Lakes, N.J.) and
cultured as described above.
Cultures were changed to growth factor-free basic medium overnight and
treated with various concentrations of CAP37 (0-2000 ng/ml) for 48-72 hrs.
Recombinant human Epidermal Growth Factor (EGF 50 ng/ml, BECTON DICKINSON,
Bedford, Mass.) and recombinant human Hepatocyte Growth Factor/Scatter
Factor (HGF/SF 20 ng/ml, BECTON DICKINSON) were used as positive controls
and growth factor-free basic medium as negative control. The medium was
aspirated and new medium with CAP37 or growth factors were added to the
cultures every 24 hr. The CyQUANT Cell Proliferation Assay Kit (MOLECULAR
PROBES, Eugene, Oreg.) was used to quantify cell proliferation exactly
according to the manufacturer's specifications. Briefly, cells were
frozen, thawed, and lysed with the addition of the lysis buffer containing
the green fluorescent dye, CyQUANT GR which binds to nucleic acids and the
fluorescence levels read on fluorescent micro plate reader (fmax MOLECULAR
DEVICES, Sunnyvale, Calif.) with filters for 485 nm excitation and 538 nm
emission.
Chemotaxis Assay
Human corneal epithelial cells were cultured in basic medium overnight,
detached using trypsin-EDTA as described above and resuspended at a final
concentration of 8.times.10.sup.5 cells/ml. Chemotaxis assays were
performed using the modified Boyden chamber assay described previously
(13). Briefly, 200 (.mu.l of cell suspension was added to the upper
chamber and chemoattractants including recombinant CAP37 (10-2000 ng/ml)
and the positive control recombinant human Platelet Derived Growth
Factor-BB (PDGF-BB, 10 ng/ml, Collaborative Biomedical Products, Bedford
Mass.) in 0.1% BSA (endotoxin-low-Sigma, St. Louis) in Geys' Buffer (GIBCO)
were added to the lower chamber. The chambers were separated by an 8.0 .mu.m
pore membrane (13 mm polyvinylpyrrolidone-free, Whatman, Clifton, N.J.).
Membranes were pre-coated with 50 .mu.g/ml collagen type I rat tail
(Collaborative Biomedical Products) in 0.02N acetic acid at room
temperature for 1 hr and then air dried. Membranes were re-hydrated in
basic cell culture medium immediately prior to commencement of each
experiment. The negative control in these experiments was 0.1% BSA in Geys'
buffer. The chambers were incubated in a humidified atmosphere (37.degree.
C., 5% CO.sub.2) for 4 hr, the filters were removed, stained with
DIFF-QUICK (Dade Behring, Dudingen, Switzerland) and mounted with Permount
(FISHER SCIENTIFIC, Pittsburgh, Pa.). The filters were viewed under oil
immersion (.times.400 magnification, BH-2, Olympus, Lake Success, N.Y.)
and the total numbers of cells migrated through to the underside of the
filter were counted in five different fields on each slide. Triplicates
were set up for each experimental point.
To assess whether CAP37 had chemokinetic properties, various
concentrations of CAP37 (0, 10, 100 and 1000 ng/ml) were added to the
upper chamber as well as to the lower chamber (0, 10, 100, 500, 1000 ng/ml)
and a checkerboard assay performed according to the methodology of Zigmond
and Hirsch (46).
To determine the specific interaction of CAP37 with HCEC, we used a
previously characterized polyvalent, monospecific rabbit antiserum to
CAP37 (12) to inhibit the chemotactic activity of CAP37. CAP37 was
incubated with heat inactivated (56.degree. C. for 30 min) rabbit
antiserum at concentrations of 1: 10, 1:50, and 1:100 and chemotaxis
assays performed as outlined above using 500 ng/ml (1.3.times.10.sup.-8 M)
rCAP37. Controls included heat-inactivated antiserum alone, CAP37 alone,
PDGF alone and PDGF plus antiserum.
Flow Cytometry
Flow cytometry was used to assess the upregulation of PECAM-1 (CD31), and
the integrin molecules .beta.1 (CD29), .beta.2 (CD18), .beta.3 (CD61),
.beta.4 (CD104), .alpha.1 (CD49a), .alpha.2 (CD49b), .alpha.3 (CD49c),
.alpha.4 (CD 49d), and .alpha.v (CD51). Human corneal epithelial cells
were cultured as above and treated with CAP37 (0-2000 ng/ml) for 0-72 hr.
A corresponding culture was left untreated at each time point. Following
treatment with CAP37, cells were detached with 0.25% trypsin in 1 mM EDTA
(pH 7.4, FISHER SCIENTIFIC, Pittsburgh, Pa.), washed twice in PBS and
fixed with 0.125% paraformaldehyde (J. T. BAKER, Phillipsburg, N.J.)
overnight at 4.degree. C. The cells were washed in PBS and then incubated
in 0.5% normal goat serum and 0.5% bovine serum albumin (BSA) in PBS for
30 min to block non-specific binding sites. Cells were incubated in the
primary antibody (at concentrations described below) at 4.degree. C. for 1
hr followed by the secondary antibody (FITC-goat anti-mouse IgG,
PHARMINGEN, San Diego, Calif.) at 0.5 .mu.g/10.sup.6 cells and incubated
at 4.degree. C. for 30 min. The isotype control for these studies was FITC-labeled
mouse isotype IgG.sub.1 (PHARMINGEN). The cells were analyzed by flow
cytometry (FACS Calibur, BECTON DICKINSON, San Jose, Calif.). At least ten
thousand cells were analyzed for each sample.
Antibodies
The primary antibodies and the concentrations used in the flow cytometry
experiments are as follows: mouse anti-human PECAM-1 (CD31) monoclonal
antibody clone HEC7 (0.5 .mu.g/10.sup.6 cells, ENDOGEN, Woburn, Mass.),
mouse anti-human very late antigen 1.alpha. (VLA-1.alpha., or CD49a)
monoclonal antibody clone SR84 (0.5 .mu.g/10.sup.6 cells, PHARMINGEN),
mouse anti-human VLA-.alpha..sub.2 (CD49b) monoclonal antibody clone AK-7
(0.125 .mu.g/10.sup.6 cells, PHARMINGEN), mouse anti-human .alpha.3
(CD49c) monoclonal antibody clone C3II.1 (0.125 .mu.g/10.sup.6 cells,
PHARMINGEN), mouse anti-human VLA-4 (.alpha.4) monoclonal antibody clone
2B4 (1 .mu.g/10.sup.6 cells, R & D systems, Minneapolis, Minn.), mouse
anti human .alpha.5 (CD49e) monoclonal antibody clone VC5 (0.125 .mu.g/10.sup.6
cells, PHARMINGEN), mouse anti-human .beta..sub.1 (CD29) monoclonal
antibody MAR4 (2 .mu.g/10.sup.6 cells, PHARMINGEN), mouse anti human
.beta..sub.2 integrin (CD18) monoclonal antibody clone 6.7 (0.5 .mu.g/10.sup.6
cells, PHARMINGEN), mouse anti human .alpha..sub.v.beta..sub.3 (CD51/CD61)
monoclonal antibody clone 23C6 (0.5 .mu.g/10.sup.6 cells, PHARMINGEN), and
mouse anti human integrin .beta..sub.4 (CD104) monoclonal antibody clone
450-11A (1.0 .mu.g/10.sup.6 cells, PHARMINGEN). A purified mouse IgG.sub.1
.kappa. monoclonal immunoglobulin isotype standard (clone MOPC-31C) was
used as the isotype matched control in the flow cytometry experiments.
RT-PCR
Cultured HCEC were treated with CAP37 (1 .mu.g/ml) for 0-24 hr at
37.degree. C. Total cellular RNA was isolated from untreated and treated
HCEC according to vendor specifications (TRIzol.TM., GIBCO BRL). After
reverse-transcription of 5 .mu.g of total RNA by SuperScrip.TM. II RT (GIBCOBRL)
the resulting single stranded cDNA was amplified by PCR (BIOMETRA
TGRADIENT, Gottingen, Germany) using specific primers for ICAM-1 ((GTCCCCCTCAAAAGTCATCC
(SEQ ID NO:11) and AACCCCATTCAGCGTCACGT (SEQ ID NO: 12)); VCAM-1 ((AGTGGTGGCCTCGTGAATGG
(SEQ ID NO:13) and CTGTGTCTCCTGTCTCCGCT (SEQ ID NO:14)); PECAM-1 ((TTGCAGCACAATGTCCTCTC
(SEQ ID NO: 15) and AGCACAGTGGCAACTACACG (SEQ ID NO:16)); E-selectin ((AGAAGAAGCTTGCCCTATGC
(SEQ ID NO:17) and AGGCTGGAATAGGAGCACTCCA (SEQ ID NO:18)); and .beta.-actin
((TACCTCATGAAGATCCTCA (SEQ ID NO: 19) and TTCGTGGATGCCACAGGAC (SEQ ID
NO:20))) synthesized by the Molecular Biology Resource Facility,
University of Oklahoma Health Sciences Center. The thermocycler conditions
for ICAM-1 and VCAM-1 were 95.degree. C. for 5 min initially, with 30
cycles at 95.degree. C. for 1 min, 58.degree. C. for 45 sec, 72.degree. C.
for 1 min followed by a final extension at 72.degree. C. for 7 min. The
conditions for E-selectin were 95.degree. C. for 5 min initially, with 30
cycles at 94.degree. C. for 1 min, 58.degree. C. for 1 min, 72.degree. C.
for 1 min followed by a final extension at 72.degree. C. for 5 min. The
conditions for PECAM-1 were 95.degree. C. for 5 min initially, with 30
cycles at 95.degree. C. for 45 sec, 60.degree. C. for 1 min, 72.degree. C.
for 1 min followed by a final extension at 72.degree. C. for 5 min.
Amplified DNA fragments were separated by electrophoresis on a 1% agarose
gel and visualized by exposure to UV after ethidium bromide (0.5 .mu.g/ml)
staining. Expected sizes for ICAM-1, VCAM-1, PECAM-1, E-selectin and
.beta.-actin were 943 bp, 700 bp, 677 bp, 315 bp and 267 bp, respectively.
To assess the integrity of the cDNA, primers for human .beta.-actin were
used.
Statistical Analysis
Data from proliferation and chemotaxis and adhesion molecule studies are
presented as mean.+-.SE. Groups were compared by unpaired student's t-test
followed by ANOVA. P<0.05 was considered significant.
Results
Proliferation of HCEC in Response to CAP37
CAP37 significantly affects the proliferation of HCEC (FIG. 5, see Original Patent).
This response is both dose- and time-dependent. At 48 hours post treatment
with CAP37, there was a significant increase in proliferation over basal
levels observed in culture medium alone. Levels of proliferation obtained
with 1000-2000 ng/ml (2.7-5.4.times.10.sup.-8 M) of CAP37 were comparable
to those obtained with the two positive controls, EGF and HGF. HCEC
continued to proliferate with time and an approximately two- to three-fold
increase in cell numbers was obtained at 72 hr post treatment with 1000 ng/ml
and 2000 ng/ml of CAP37 respectively. The levels obtained with EGF and HGF
were similar to those obtained with 1000 ng/ml of CAP37.
Migration of HCEC in Response to CAP37
We investigated whether CAP37 was chemotactic for HCEC using the modified
Boyden chemotaxis technique. Data shown in FIG. 6 indicate that CAP37 is a
strong chemoattractant for HCEC. It was maximally chemotactic in the range
of 500 ng/ml to 1000 ng/ml and was reduced but still measurably active at
2000 ng/ml. The levels of migration in response to CAP37 were comparable
to those obtained with the positive control, PDGF. The dose response
obtained with CAP37 shows the typical bell-shaped curve indicative of a
chemoattractant. However, an important issue that requires clarification
when determining movement of cells in response to a mediator is whether
this migration is due to directed movement (chemotaxis) as opposed to
merely accelerated random motion (chemokinesis). The checkerboard assay
(46) has been traditionally employed to distinguish chemotaxis from
chemokinesis. Our experiments demonstrate that the effect of CAP37 on HCEC
is predominantly chemotactic (Table I, see Original Patent). Most
chemoattractants display a certain level of chemokinesis particularly at
higher concentrations (46). The data obtained clearly demonstrate that
there is an increase in numbers of cells migrating across the filter when
increasing concentrations of CAP37 are present in the lower chamber, but
absent from the upper chamber i.e. standard chemotaxis assay (Table I, row
1, see Original Patent). The addition of CAP37 to the upper chamber
resulted in a reduction of the chemotactic gradient across the membrane,
with corresponding reduction in levels of migration. The values on the
diagonal in Table I represent chambers that were set up with equal
concentrations of CAP37 across the membrane and clearly indicate that the
levels of migration are not significantly greater than background. The
values in Table I are represented as total numbers of cells migrated
rather than percent of control to indicate the absolute values of cells
migrating to the underside of the filter.
To demonstrate the specificity of this chemotactic response, an antibody
previously shown to be specific for CAP37 was used to inhibit the
migration of cells in response to CAP37. FIG. 7 (see Original Patent)
indicates a dose response inhibition of the chemotactic response, with
significant inhibition (p<0.01) obtained with the antibody at 1:10
dilution. As predicted, the antibody did not have an inhibitory effect on
the chemotactic activity of PDGF for HCEC.
Effect of CAP37 on adhesion molecules on HCEC
RT-PCR was performed using primers specific for ICAM-1, VCAM-1, PECAM-1
and E-selectin. Treatment of HCEC with CAP37 indicates a clear
upregulation of ICAM-1 message beginning at 2 hr and lasting through 24 hr
(FIG. 8 (see Original Patent)). Maximum expression of ICAM-1 message was
seen between 2 and 4 hr. PECAM-1 was also upregulated by CAP37. Unlike the
upregulation of ICAM-1 message, upregulation of PECAM-1 message was
transient. It was detected at 2 hr after stimulation, maximum at 4 hr and
could not detected after 6 hr. HCEC did not show increase in mRNA
expression of VCAM-1 and E-selectin in response to CAP37 treatment.
The expression of PECAM-1 in response to CAP37 treatment was further
confirmed using flow cytometry (FIG. 9 (see Original Patent)). Significant
protein expression was observed on HCEC at 6 hr, was maintained through 12
hr and waned by 24 hr, corroborating our findings in FIG. 8. The kinetics
of this response to CAP37 appeared to follow that of TNF-.alpha. up to 12
hr. Thereafter the effect of TNF-.alpha. was more sustained, lasting until
24 hr (not shown).
Upregulation of .alpha.1, .alpha.2, .alpha.3, .alpha.4, .alpha.v and
.beta.1, .beta.2, .beta.3, .beta.4 integrins in response to CAP37 was also
assessed using flow cytometry. Table II (see Original Patent) summarizes
the data obtained from these analyses. Of the 8 integrin molecules
analyzed only two showed significant upregulation. CD49c (.alpha.3) was
initially upregulated at 4 hr, and the level of protein expression was
sustained through 24 hr (FIG. 10 (see Original Patent)). CD49c protein
levels on HCEC at 48 and 72 hr returned back to constitutive levels (not
shown). There was high contitutive expression of CD49c, as indicated by
strong staining on untreated HCEC. The other integrin molecule to be
upregulated by CAP37 was CD29 (.beta.1). The upregulation is clearly
significant by 6 hr, increases to maximum levels between 12 and 48 hr, and
although reduced at 72 hr is still significantly elevated above background
constitutive levels (FIG. 11, see Original Patent). The flow cytometry
analysis indicates a low level of constitutive expression of CD29 which
remains constant throughout all time points in this experiment. TNF-.alpha.
was used as the positive control in these experiments.
As indicated by the results, the presence of the novel inflammatory
molecule CAP37 has been identified in the eye. The in vitro evidence
presented indicates its expression in HCEC and stromal keratocytes in
response to inflammatory cytokines such as TNF-.alpha. and IL-1.beta.. The
results show that CAP37 modulates corneal epithelial cell functions
including proliferation, migration and upregulation of adhesion molecules
important in epithelial-extracellular matrix interactions. In addition to
upregulation of adhesion molecules important in epithelial-extracellular
matrix interactions, CAP37 also regulates the expression of adhesion
molecules of the immunoglobulin superfamily important in
leukocyte-epithelial interactions. Specifically, CAP37 upregulated the
adhesion molecules ICAM-1 and PECAM-1. CAP37 modulates infections in the
eye through its ability to act as an antibiotic, elicit leukocyte
recruitment and affect corneal epithelial cells functions, thereby
regulating corneal inflammation and healing.
Utility
The present invention contemplates the use of a native, synthetic, or
recombinant CAP37, or peptide portions thereof, or derivatives thereof, as
described herein, to treat various conditions of the eye including
infections. The invention further contemplates the use of a native,
synthetic, or recombinant CAP37, or peptide portions thereof, or
derivatives thereof, in the treatment of corneal ulcers and wounds. The
invention also contemplates the use of a native, synthetic, or recombinant
CAP37, or peptide portions or derivatives thereof, as a disinfectant for
cleaning or sterilization of contact lenses and as a storage solution for
preventing contact lenses from becoming contaminated with bacteria while
in contact lens storage cases. The invention also contemplates coating
contact lenses with a native, synthetic, or recombinant CAP37, or an
antibiotic peptide portions or derivatives thereof (and contact lenses
thus coated), to inhibit, prevent or treat infections, bacterial keratitis
and/or the growth of biofilms on or by contact lenses. The invention also
contemplates a method for storage of mammalian corneal tissue or
transplants in media containing a native, synthetic, or recombinant CAP37,
or peptide portions or derivatives thereof, or at bactericidal
concentrations for aseptic transportation and storage.
CAP37 peptides which can be used in the present invention are functional
(antibiotic) and immunomodulatory peptides of CAP37 peptides of CAP37 or
derivatives thereof and include, but are not limited to, peptide 20-44,
peptide 23-42, peptide 102-122, peptide 120-146, and monocysteine
derivatives of peptides 20-44 and 23-42 as described in U.S. Pat. No.
6,107,460 which is hereby expressly incorporated by reference herein in
its entirety and as referred to elsewhere herein.
More particularly the invention includes, but is not limited to: 1. Use of
a native, synthetic, or recombinant CAP37, or peptides thereof, and/or
derivatives thereof, as described herein, as an ocular antibiotic
treatment, for conjunctivitis or bacterial keratitis, particularly in
those cases due to Pseudomonas aeruginosa and Staphylococcus aureus. 2.
Use of a native, synthetic, or recombinant CAP37, or peptides thereof,
and/or derivatives thereof, as described herein, as a cleaning and
sterilization procedure for storing contact lenses in storage cases. Since
Pseudomonas aeruginosa is the most common causative agent, contact lenses
could be stored in a bactericidal solution of a native, synthetic, or
recombinant CAP37, or peptides thereof, and/or derivatives thereof as
described herein. This would be an important mechanism to prevent or
inhibit ocular infections before they are initiated. 3. Extended wear
contact lenses could be manufactured with a surface coating of a native,
synthetic, or recombinant CAP37, or bactericidal peptides thereof, and/or
derivatives thereof, as described herein, as a preventive method to
prevent or inhibit infections from occurring or biofilms from forming. 4.
Human corneal transplants could be stored in media containing bactericidal
quantities of a native, synthetic, or recombinant CAP37, or peptides
thereof, and/or derivatives thereof, as described herein, during
transportation and storage. 5. A native, synthetic, or recombinant CAP37,
or peptides thereof, and/or derivatives thereof, as described herein,
could be used in treating ulcers and wounds of the cornea to promote
healing. 6. Use of a native, synthetic, or recombinant CAP37, or
bactericidal peptides thereof, and/or derivatives thereof, as described
herein, to treat serious bacterial infections which occur
post-operatively. For example, endophthalmitis, including post-operative
endophthalmitis due to coagulase negative Staphylococcus, is a major
problem. Infection of the conjunctival filtering bleb created by glaucoma
surgery, known as "blebitis", due most commonly to Staphylococcus aureus,
Streptococcus and Hemophilus are further targets for treatment with a
native, synthetic, or recombinant CAP37, or peptides thereof, and/or
derivatives thereof, as described herein.
The use of a native, synthetic, or recombinant CAP37, or peptides thereof,
and/or derivatives thereof, described herein, as antibiotics is
advantageous over other available therapies since its mode of action is
different from traditional antibiotics. Therefore the chances of
antibiotic resistant organisms arising as a result of this therapy are far
less than with traditional antibiotics. Since CAP37 is a naturally
occurring protein or peptide, the chances of allergic reactions and
toxicity are less. It has activity with a relatively narrow spectrum, but
is active against both Pseudomonas and Staphylococcus, the two most common
causative organisms of bacterial keratitis. Further, a native, synthetic,
or recombinant CAP37, or peptides thereof, and/or derivatives thereof, are
generally bactericidal rather than bacteriostatic.
A native, synthetic, or recombinant CAP37, or peptides thereof, and/or
derivatives thereof, as described herein, are active against the two most
common causative organisms, but have limited activity against a number of
other Gram negative and Gram positive bacteria, therefore, treatment using
them would not be overly toxic to normal flora. The CAP37 peptides in
particular are small, easily synthesized, and can be delivered in required
concentrations topically.
In one treatment protocol, the proteins or peptides described herein are
provided at a concentration of 200 .mu.g/ml in a saline or "natural tears"
solution, but may be at a concentration from about 10 .mu.g/drop to 1000 .mu.g/drop
(50 .mu.l/drop). Drops may be administered to a subject's eye, for
example, every 15 minutes to 1 hour for the first 2-3 days of treatment,
followed by dosing every 4 hours for 14 more days. The proteins or
peptides described herein could also be applied to the eye as an ointment.
The CAP37 proteins or peptides can be applied by intravitreal injection
for treatment of endophthalmitis in a manner well known to those of
ordinary skill in the art.
The following U.S. patents are hereby expressly incorporated herein by
reference in their entirety: U.S. Pat. Nos. 5,607,916; 5,650,392;
5,627,262; 5,877,151; 6,071,879; 6,107,460; 5,458,874; and 5,484,885.
References cited herein are also expressly incorporated by reference
herein in their entireties.
Claim 1 of 10 Claims
1. A method of treating an infection in
an eye of a mammal comprising: providing a therapeutically-effective
amount of a peptide consisting of the sequence SEQ ID NO:6, SEQ ID NO:7,
or SEQ ID NO:8; and administering the therapeutically-effective amount of
the peptide to the eye of the mammal. ____________________________________________
If you want to learn more
about this patent, please go directly to the U.S.
Patent and Trademark Office Web site to access the full
patent.
|