Download ARVO 2015 Annual Meeting Abstracts 435 Mechanisms of wound

ARVO 2015 Annual Meeting Abstracts
435 Mechanisms of wound repair: Lessons learned from the eye Minisymposium
Wednesday, May 06, 2015 11:00 AM–12:45 PM
605/607 Minisymposium
Program #/Board # Range: 4386–4391
Organizing Section: Lens
Contributing Section(s): Cornea, Immunology/Microbiology
Program Number: 4386
Presentation Time: 11:00 AM–11:25 AM
Site specific differences in the inflammatory response to injury
Luisa A. DiPietro. University of Illinois at Chicago, Chicago, IL.
Presentation Description: Problems with skin wound healing
are a major health issue in the US, as more that 6 million persons
develop serious problems with wound healing each year. The two
most important problems experienced by patients are 1) non-healing
wounds, and 2) wounds that heal with excessive scars. Interestingly,
scars are rare in wounds of the oral cavity, suggesting that this
tissue heals differently than skin. The comparison of the wound
healing process in skin and oral mucosa has shown that oral mucosal
wounds heal more quickly, with reduced inflammation, and with a
more refined healing response. The study of the response of the oral
mucosa to injury suggests therapeutics, including the modulation of
inflammation, that might be employed to improve healing outcomes
in other tissues.
Commercial Relationships: Luisa A. DiPietro, None
Support: NIH GM50875
Program Number: 4387
Presentation Time: 11:25 AM–11:45 AM
Neutrophils Express Oncomodulin and Promote Optic Nerve
Regeneration
Larry Benowitz. 1Depts. of Neurosurgery and Ophthalmology,
Harvard Medical School, Boston, MA; 2Neurosurgery, Neurobiology,
Boston Children’s Hospital, Boston, MA.
Presentation Description: Like most mature CNS pathways,
the optic nerve cannot regenerate if injured, leaving victims of
ischemic or traumatic nerve damage, glaucoma or other degenerative
diseases with permanent visual losses. The induction of intraocular
inflammation partially reverses this inability and enables retinal
ganglion cells (RGCs) to regenerate axons part-way through the
injured optic nerve. In cell culture, we found that cells of myeloid
origin secrete a protein that enables mature RGCs to grow axons in
the presence of two co-factors, mannose and elevated cAMP. We
isolated the active protein by HPLC, SDS-PAGE, and cell culture
bioassays, and identified it via mass spec as oncomodulin (Ocm), a
small Ca++ -binding protein related to parvalbumin1,2. Ocm mRNA
and protein increase dramatically in the eye within 12 hours of
inducing intraocular inflammation, and gain- and loss- of function
studies show that Ocm mediates most of the pro-regenerative effect
of inflammation in vivo2-4. Combining intraocular inflammation with
deletion of the pten gene enables some RGCs to regenerate axons
from the eye to the brain in ~ 10 weeks, forming connections in
anatomically appropriate target areas and restoring simple visual
responses5. Flow cytometry, immunostaining, and quantitative PCR
show that, whereas activated neutrophils and macrophages both
express high levels of Ocm, neutrophils represent the more important
biological source. The number of neutrophils greatly exceeds that
of macrophages in the first several days, and immune-depletion of
neutrophils nearly eliminates the effect of pro-inflammatory agents
on axon regeneration despite the persistence of macrophages6.
Injection of a peptide antagonist of Ocm or a neutralizing antibody
similarly produce a near-complete loss of regeneration following
nerve injury and pro-inflammatory stimulation3,6. These results
show that inflammation enables mature RGCs to undergo extensive
axon regeneration, and that this effect is mediated primarily by
oncomodulin, an atypical growth factor produced by cells of myeloid
origin.
________________________
1
Y. Yin et al., J Neurosci 23, 2284 (2003); 2Y. Yin et al., Nat Neurosci
9, 843 (2006); 3Y. Yin et al., Proc Natl Acad Sci U S A 106, 19587
(2009); 4T. Kurimoto et al., J Neurosci 30, 15654 (2010); 5S. de Lima
et al., Proc Natl Acad Sci U S A 109, 9149 (2012); 6T. Kurimoto et
al., J Neurosci 33, 14816 (2013).
Commercial Relationships: Larry Benowitz, Boston Children’s
Hospital (P)
Support: NIH/NEI EY 05690, NIH/IDDRC P30 HD018655, Dr.
Miriam and Sheldon G. Adelson Medical Research Foundation,
Kawasaki Medical School Alumni Association Fund for Foreign
Study, Grant-in-Aid for Young Scientists B (23792021)
Program Number: 4388
Presentation Time: 11:45 AM–12:00 PM
Subbasal Nerves Fail to Project to the Mouse Corneal Apex After
Corneal Debridement
Mary Ann Stepp. Anatomy and Regenerative Biology Dept., George
Washington University, Washington, DC.
Presentation Description: Spontaneous erosions form within 2-4
weeks after debridement wounds to the mouse cornea but the exact
causes of this pathology remain under investigation. Here we studied
leukocyte recruitment and reinnervation of the corneal subbasal
nerves after 1.5 mm corneal wounds to determine the mechanisms
that lead to the development of epithelial defects in the adult Balb/c
mouse. The mouse cornea has dense network of subbasal axons
that enter the cornea at the limbus and run parallel to the basement
membrane beneath the corneal epithelial basal cells towards the
center of the cornea terminating in a swirling pattern termed the
vortex at the corneal apex. A 1.5 mm trephine was placed on the
ocular surface and an impression was made by rotating it. The
impression serves as a guide to allow generation of a 1.5 mm wound;
it penetrates the corneal epithelium and severs the subbasal nerves
partially denervating the 1.5 mm area. When we wounded corneas by
removing 1.5 mm of corneal epithelial tissue by either dulled blade
or rotating burr, we found that subbasal axons were unable to target
their projections all the way to the corneal apex and fully reinnervate
the cornea. By contrast, after using the trephine alone and leaving
the epithelium intact, the corneas all reinnervated completely with
subbbasal axons targeting their projections to the corneal apex where
they reformed a vortex. To allow cells to migrate to the corneal center
after dulled blade and rotating burr wounds, the corneal epithelial
cells at the periphery disassemble their hemidesmosomes. After
migration is completed, they resynthesize a basement membrane
and hemidesmosomes to allow firm adhesion; these events can take
2 weeks or longer. Trephine only injuries induce hemidesmosome
reassembly in the epithelial cells at the site of trephine mark;
the corneal cells at the apex, where the mechanical forces due to
blinking are maximal, maintain their hemidesmosomes after trephine
wounding. Defective axon targeting is seen after wounds that induce
corneal epithelial cell migration but not after denervation alone
without induction of cell migration. In addition to gaining insight into
corneal erosions, this presentation will highlight the advantages to
using the mouse cornea to gain insight into axonal regeneration in the
peripheral nervous system.
Commercial Relationships: Mary Ann Stepp, None
Support: R21 23106 (MAS, APG), R01 21784 (MAS, ASM), RO1
8512 (MAS)
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at [email protected].
ARVO 2015 Annual Meeting Abstracts
Program Number: 4389
Presentation Time: 12:00 PM–12:15 PM
Regulation of cell motility by galectin-3 and MMP9
Pablo Argueso. Schepens Eye Research Institute, Harvard University,
Boston, MA.
Presentation Description: Epithelial cells require significant
fluidity to change their shape and rearrange their position to assume
a migratory phenotype during tissue repair—this involves the
remodeling of tight junctions with neighboring cells and of the
extracellular matrix. However, the dynamics that initiate these
movements remain to be determined. Here, we reveal a hitherto
unknown function of the carbohydrate-binding protein galectin-3 in
destabilizing cell-cell junctions and cell-cell interactions by inducing
matrix metalloproteinase expression. Further, we demonstrate a
major role for the oligomeric form of galectin-3 in these processes by
interacting with and clustering the matrix metalloproteinase inducer
CD147 on the cell surface.
Commercial Relationships: Pablo Argueso, None
Support: NH Grant EY014847
Program Number: 4390
Presentation Time: 12:15 PM–12:30 PM
Mechanisms of wound-healing in the lens: The role of repair cell
subpopulations
A. Sue Menko. Dept. of Pathology, Anatomy and Cell Biology,
Thomas Jefferson University, Philadelphia, PA.
Presentation Description: In epithelial tissues wound healing
involves the collective movement of the injured epithelium directed
by a population of mesenchymal leader cells at the wound edge.
We have studied epithelial wound repair in the visual system using
a lens mock cataract surgery model. Here we found that the leader
cells that direct repair of this injured ocular epithelium can be traced
to a vimentin-rich progenitor subpopulation of mesodermal origin
resident to the lens. In the uninjured lens, these repair cell progenitors
are located in niches amongst the cells of the epithelium. This finding
was unexpected as prior to our studies the lens was thought to contain
only two cell types, lens epithelial cells and their differentiated
counterparts, the lens fiber cells. The fiber cell mass is removed
during cataract surgery, leaving behind an injured epithelium, the
denuded basement membrane of the posterior lens capsule, and the
repair cell progenitors. This presentation will provide evidence of the
presence of cells in the lens with reparative properties that are of both
mesoderm and leukocyte lineages. These repair cells are present in
embryonic and adult lens tissue. We will show how these repair cells
become associated with the lens during development, and discuss
the possibility that association of repair cells with the lens could be
a dynamic process that continues in the adult. The mesenchymal
repair cells of the lens were found to be rapid responders to
injury, migrating immediately to the wound edge and extending
lamellipodial processes along the denuded basement membrane of the
lens capsule. These features are dependent on vimentin intermediate
filament function, as is the repair process itself. We will discuss the
function of repair cells in modulating an effective wound response of
the epithelium. In addition, we will show evidence that these repair
cells have high profibrotic potential, and share unique molecular
features with mesenchymal repair cells in other tissue types that have
similar ability to attain a myofibroblast phenotype. Evidence will
be presented that the transition of repair cell to a myofibroblast is
promoted through a mechanotransduction-signaling event.
Commercial Relationships: A. Sue Menko, None
Support: NIH Grant EY021784
Program Number: 4391
Presentation Time: 12:30 PM–12:45 PM
Myofibroblast generation in cornea and lens: modulation of
Smad signal by extracellular matrix
Shizuya Saika. Dept of Ophthalmology, Wakayama Medical
University, Wakayama, Japan.
Presentation Description: Myofibroblast appears in the fibrotic
tissues that are undergoing wound healing process. In the eye it
is observed in corneal stroma, endothelium, crystalline lens or
proliferative vitreoretinopathy tissue of origin of retinal pigment
epithelium. Its phenotype is quite similar among myofibroblasts of
each ocular tissue although the embryonic germinal origins differ
from each other. Transforming growth factor β (TGFβ)/Smad signal
plays a central role in the process of myofibroblast generation;
keratocyte-myofibroblast conversion or epithelial-mesenchymal
trantision (EMT), and is known to be further modulated by signals
derived from binding of extracellular matrix (ECM) to cell surface
receptors. In the current talk the mechanisms of modulation of TGFβ
signal and EMT as well as keratocyte-myofibroblast conversion
by matricellular proteins, i. e., osteopontin, tenscin-C and lumican
will be reviewed. Although overall signals derived from these ECM
components support Smad signal and positively modulate EMT or
keratocyte-myofibroblast conversion, the detailed mechanisms of
actions seem differ among those by each ECM component
Commercial Relationships: Shizuya Saika, None
Support: The Grant from the Ministry of Education, Science, Sports
and Culture of Japan (C19592036)
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at [email protected].