In addition to studying the pathophysiology of glaucoma, we are also interested in any potential treatments. Glaucoma is associated with impairment in retrograde transport of neurotrophic factors to retinal ganglion cell (RGC) bodies. Previously we demonstrated that bone marrow-derived MSC (BMSC) transplantation is protective in a rat model of glaucoma and that factors secreted by BMSC are essential for neuroprotection. To elucidate the nature of neuroprotective factors we used exosomes produced by BMSC and tested them in a rat optic nerve crush (ONC) model. Treatment of primary retinal cultures with BMSC-exosomes demonstrated significant neuroprotective and neuritogenic effects. In vivo, intravitreal injection of BMSC-derived exosomes, but not fibroblast-derived exosomes, provided statistically significant RGC neuroprotection, regeneration of their axons while partially preventing RGC axonal loss and RGC dysfunction. Exosomes successfully delivered their cargo into inner retinal layers after intravitreal injection and the effects were reliant on miRNA, demonstrated by the diminished therapeutic effects of exosomes derived from BMSC after knockdown of Argonaute-2, a key miRNA effector molecule. RNAseq identified 43 miRNAs upregulated in BMSC exosomes in comparison to fibroblast exosomes. The role of individual miRNA in neuroprotection and identification of their targets in RGCs are under investigation. BMSC-derived exosomes promote similar therapeutic effects in two tested rat models of glaucoma. This study supports the use of BMSC-derived exosomes as a cell-free therapy for traumatic and degenerative ocular disease. Using the same ONC model as above, intravitreal injection of adeno-associated viral vectors to express a number of candidate proteins is being explored to provide neuroprotection and/or axon regeneration to injured RGC. Expression of some of these proteins led to a profound neuroprotective and partial restoration of visual functions and the molecular mechanisms are currently under investigation. We continued our investigations of the molecular mechanisms involved in the protection of retinal ganglion cells by PDGF-AA. Our data indicate that the neuroprotective effect of PDGF-AA in a rodent model of glaucoma could be mediated by astrocytes and/or a sub-population of amacrine cells. We suggest that after intravitreal injection of PDGF-AA, these cells respond by secreting factors that protect RGCs. The characterization of molecular changes in astrocytes and sub-population of amacrine cells expressing PDGFR is under investigation.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIAEY000318-20
Application #
9555671
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
20
Fiscal Year
2017
Total Cost
Indirect Cost
Name
U.S. National Eye Institute
Department
Type
DUNS #
City
State
Country
Zip Code
Mead, Ben; Amaral, Juan; Tomarev, Stanislav (2018) Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Promote Neuroprotection in Rodent Models of Glaucoma. Invest Ophthalmol Vis Sci 59:702-714
Mead, Ben; Tomarev, Stanislav (2018) Retinal ganglion cell neuroprotection by growth factors and exosomes: lessons from mesenchymal stem cells. Neural Regen Res 13:228-229
Joe, Myung Kuk; Lieberman, Raquel L; Nakaya, Naoki et al. (2017) Myocilin Regulates Metalloprotease 2 Activity Through Interaction With TIMP3. Invest Ophthalmol Vis Sci 58:5308-5318
Takahama, Shokichi; Adetunji, Modupe O; Zhao, Tantai et al. (2017) Retinal Astrocytes and GABAergic Wide-Field Amacrine Cells Express PDGFR?: Connection to Retinal Ganglion Cell Neuroprotection by PDGF-AA. Invest Ophthalmol Vis Sci 58:4703-4711
Mead, Ben; Tomarev, Stanislav (2017) Bone Marrow-Derived Mesenchymal Stem Cells-Derived Exosomes Promote Survival of Retinal Ganglion Cells Through miRNA-Dependent Mechanisms. Stem Cells Transl Med 6:1273-1285
Mead, Ben; Tomarev, Stanislav (2016) Evaluating retinal ganglion cell loss and dysfunction. Exp Eye Res 151:96-106
Morgan, Joshua T; Kwon, Heung Sun; Wood, Joshua A et al. (2015) Thermally labile components of aqueous humor potently induce osteogenic potential in adipose-derived mesenchymal stem cells. Exp Eye Res 135:127-33
Joe, Myung Kuk; Nakaya, Naoki; Abu-Asab, Mones et al. (2015) Mutated myocilin and heterozygous Sod2 deficiency act synergistically in a mouse model of open-angle glaucoma. Hum Mol Genet 24:3322-34
Johnson, Thomas V; DeKorver, Nicholas W; Levasseur, Victoria A et al. (2014) Identification of retinal ganglion cell neuroprotection conferred by platelet-derived growth factor through analysis of the mesenchymal stem cell secretome. Brain 137:503-19
Kwon, Heung Sun; Nakaya, Naoki; Abu-Asab, Mones et al. (2014) Myocilin is involved in NgR1/Lingo-1-mediated oligodendrocyte differentiation and myelination of the optic nerve. J Neurosci 34:5539-51

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