Crystallins as Neuroprotective and Neuroregenerative Treatments in Experimental Glaucoma

• Applicant: Professorin Dr. Verena Prokosch-Willing
• Subject Area: Ophthalmology
• Term: since 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 263817636

Glaucoma is a leading cause of blindness, characterized by progressive retinal ganglion cell (RGC) loss. Lowering of intraocular pressure (IOP), as a key risk factor, is currently the only treatment to slow glaucoma. However, RGCs continue to undergo apoptosis despite IOP lowering . The situation is exacerbated by RGCs, as CNS neurons, lacking the ability to regenerate their axons. A better understanding of the mechanisms and associated with RGC injury, apoptosis and regenerative failure remains an enormous challenge. In our first funding period (PR 1569/1-1) “Molecular biomarkers in the treatment of experimental glaucoma and their functional impact on apoptotic- and regeneration-related signalling pathways”, we analysed different glaucoma models in detail at functional, cellular and molecular levels. We established a proteomic profile, identified molecular markers and looked into neuroprotection and neuroregeneration related to them. Crystallins were found to be one of the most striking markers. We deciphered, that crystallins appeared to show very specific expression patterns in retinal and vitreous samples in the course of the disease. Intravitreal injection of alphaA and betaB2 in vivo exerted neuroprotective effects. BetaB2 crystallin and betaB2 expressing NPCs given intravitreally even promoted neuroregeneration. Besides that crystallins were uptaken from the medium into the cells, transported to the site of lesion and seemed to exert effects via neurotrophic and calcium-dependent pathways. However, crystallins- known as heat-shock proteins- comprise a whole family of alpha (A and B), beta (A1/3, A2, A4, B1, B2, B3) und gamma (A, B, C, D, E, S) crystallins. The importance and interplay of the individual crystallins, the precise neuroprotective and neuroregenerative mechanisms still remain unclear and must be elucidated before their potential in the treatment of glaucoma can be realized. This will be addressed in the second funding period.Firstly, targeted proteomics will help to analyse the whole crystallin family including the less abundant crystallins and their role in regenerative and degenerative pathways. The 5 key crystallins will be identified, corresponding relevant interactions and signalling pathways deciphered. The neuroprotective and regenerative potential of the five presumably most powerful will be assessed by examining retinal explants and isolated RGCs under regenerative and degenerative conditions in vitro. Blocking experiments and specific analysis of the tissue and supernatant will verify the signalling pathways. The last step will analyse neuroprotection and regeneration of the two most promising crystallins in vivo, with the aim of proving novel treatment alternatives for glaucoma.

• DFG Programme: Research Grants