research Interest

Welcome to the Wohl lab!

Our major goal is to fight visual impairment and blindness at the cellular and molecular level. Many retinal diseases such as age-related macular degeneration (AMD), diabetic retinopathy glaucoma, or retinitis pigmentosa lead to impairment of vision and in most cases, blindness. Although the impairment of vision is often due to primary damage to the retinal neurons, glia cells play significant roles in this process and can induce secondary neuronal loss. We want to understand the role of glia during retinal diseases and our focus lies on Müller glia, the major glia cell type in the retina. We are interested in two major questions:

1) How can we regenerate a diseased retina?

2) How can we attenuate diseases and prevent additional damage to the retina?

Müller Glia

First a few words about Müller glia and why they are so important. Müller glia are fascinating cells. They are the predominant glia in the neural retina and are generated last during retinogenesis, the process when all six retinal neuronal cells and the Müller glia are formed. They are named after Professor Heinrich Müller who discovered and described them in 1851. These glia, similar to astrocytes in the brain, are the support cells in the retina and have a variety of other functions including maintaining the homeostasis of the tissue and protection after injury or disease.  As part of their protective function, Müller glia undergo morphological and molecular changes to create a barrier to isolate damaged/diseased tissue from healthy tissue. This barrier however also creates a non-permissive environment for regeneration and is one of the reasons why our retinas cannot regenerate. Furthermore, this glial response, called gliosis, can trigger detrimental effects including secondary neuronal loss and inflammation. It is a very complex process and includes a variety of factors and mechanisms which are not fully understood.

But that’s not all. Müller glia can serve as an endogenous source for regeneration, at least in lower vertebrates such as fish. In the event of damage, fish Müller glia turn into stem-cell like cells, called retinal progenitor cells, divide a few times, and then give rise to new functional neurons that replace the lost ones. A remarkable capability that unfortunately is silenced in mammals including us humans. However, even our (mammalian) Müller glia have a molecular composition that is similar to retinal progenitor cells and many experts are eager to decipher the mechanisms of how to awaken Muller glia as an endogenous source for retinal regeneration in mammals. A way to force them to wake up is a process called reprogramming by artificially inducing factors that are naturally found in fish Müller glia during regeneration.

Molecules that play a role in both Müller glia-driven retinal regeneration in fish and gliosis in mammals are microRNAs.

microRNAs

microRNAs or short miRNAs are molecules known to play in role in Müller glia development and function. microRNAs are small RNA molecules present in every cell of the body and act as so-called translational repressors. That means that messenger RNA (mRNA, transcribed from DNA) is not translated into protein. In other words, miRNAs are epigenetic regulators that prevent the generation of proteins even if the gene of this protein is active. These proteins can be receptors on the cell surface or transcription factors inside the nucleus. About 1000 different miRNAs have been identified so far and it is known that they have an impact on development, independent of tissue origin and cell type. However, their expression pattern can vary between different cell types, developmental stages (maturation of a cell), as well as physiological and pathophysiological conditions. For the latter, there is increasing evidence that microRNAs play an important role in various diseases and can be used as a biomarker for certain diseases. miRNAs play also an important role during retinal regeneration in fish by regulating the conversion of the glia into progenitor cells.

Reprogrammed primary mouse Muller glia after miRNA treatment

The Role of microRNAs in Retinal Glia Function

In my laboratory, we investigate

1) The role of miRNAs in Müller glia reprogramming. This includes the role of miRNAs during late retinal development in order to understand if miRNAs are required for the generation of late-born retinal cells, which include rod photoreceptors and bipolar cells (interneurons), as well as Müller glia. miRNAs that are required for cell fate development are very likely successful reprogramming factors.

2) The impact of miRNAs in the different phases of glial activation after injury and/or disease.

This will give us a better understanding of the underlying mechanisms of regeneration and gliosis. The long-term goals are 1) to utilize microRNAs as a tool for regenerative medicine by stimulating endogenous glia to replace lost neurons. And 2) to develop new approaches and therapies to attenuate the glial response after damage to reduce secondary neuronal loss (neuroprotection) and allow potential axonal regeneration of remaining neurons.

Methods and Techniques

Established methods in the lab include:

• transgenic mouse models and in vivo manipulations of microRNAs

• primary cell cultures (see protocol published with Jove: https://dx.doi.org/10.3791/63651-v)

• immortalized cell line cultures (in vitro)

• organotypic explant cultures (ex vivo)

• microRNA profiling and analysis

• bulk and single-cell RNA-sequencing

• light damage model

• OCT

• ERG

• protein assays

• fluorescence microscopy including time-lapse and confocal laser scanning microscopy

and much more.

Ongoing research based on PREVIOUS work

1: Müller Glia have a specific set of mircoRNAs

Müller glia have a specific set of microRNAs different from neurons and progenitor cells. However, besides distinct miRNA sets, there are also miRNAs that Müller glia share with other cell types.

Wohl, S. G. and Reh, T.A., 2016. The microRNAs expression profile of mouse Müller glia in vivo and in vitro. Scientific Reports 6, 35423; doi 10.1038/srep35423.

Wohl et al., 2019. MicroRNAs miR-25, let-7 and miR-124 regulate the neurogenic potential of Muller glia in mice. Development 146;10.1242/dev.179556

2: microRNAs can convert Müller glia into retinal Progenitors

The microRNAs neuronal microRNA miR-124 (in combination with miR-9 and miR-9*) can reprogram Müller glia into Ascl1+ retinal progenitor cells that give rise to retinal neurons. The combination of miR-124/9/9* together with the transcription factor Ascl1 accelerates reprogramming. Moreover, over-expression of the retinal progenitor microRNA miR-25 and inhibition of the Müller glia microRNA let-7 leads to conversion of Müller glia into retinal progenitors and subsequent neuronal differentiation.

Wohl, S. G. and Reh, T.A., 2016. miR-124-9-9* potentiates Ascl1-induced reprogramming of cultured Müller glia. Glia 64, 743-762.

Wohl, S. G., Hooper M. and Reh, T.A., 2020. MiroRNAs miR-125, let-7 and mIR-124 regulate the neurogenic potential of Müller glia in mice. Development, 146.

3: microRNAs are essential for Müller glia function and overall retinal health

The depletion of microRNAs in Müller glia (by deleting Dicer, the enzyme that generates mature microRNAs) leads to significant disruptions in the retinal architecture. Müller glia proliferate, migrate and form strange aggregations but do not function properly anymore. As a consequence, photoreceptors die and a phenotype that resembles retinitis pigmentosa can be observed over time. Experiments using organotypic explants cultures show that supplementation with miRNAs helps to rescue the Müller glia phenotype and overall retinal architecture. This implies that dysregulation of miRNAs in Müller glia could be an additional cause of degenerative diseases and consequently, treating diseased retinas with miRNAs could help rescue the tissue.

LAB Members

Email: swohl@sunyopt.edu
phone: +1 212 938 5822

Stefanie G. Wohl, Principal Investigator

I was born in Germany and studied Biology (Diploma) at the Friedrich Schiller University (FSU) of Jena, Germany, and was always fascinated by neurobiology, regeneration, and stem cell research. In 2003, I started working as an undergraduate in the laboratory of Stefan Isenmann, M.D., at the Clinic of Neurology (FSU) in Jena which investigated axonal regeneration of the optic nerve. I continued my work as a graduate student under the supervision of Stefan Isenmann, M.D., Christian Schmeer, Ph.D., and Jürgen Bolz, Ph.D., my professor of neurobiology, who was trained by Heinz Wässle, Ph.D.  My research topic was the identification of putative stem cell-like cells after moderate and severe injury. This included studies of neurodegeneration, gliosis, and immunological cell responses. At this time I became intrigued with Müller glia in the retina via the work of Drs. Andreas Reichenbach and Andreas Bringman from the University of Leipzig. By coincidence, I discovered a subtype of microglia that transiently increased in number after optic nerve injury expressing a marker that was primarily associated with stem/ progenitor cells (nestin). In 2011, I received my Ph.D. (neuroscience/ ophthalmology) with the highest honors (summa cum laude) from the Friedrich Schiller University of Jena. For my post-doc training, I decided to go abroad and joined the laboratory of Tom Reh at the University of Washington in Seattle. During this time I discovered my interest in and passion for microRNAs and focused my research on Müller glia. In September 2018, I became an Assistant Professor at the State University of New York, College of Optometry in the Department of Biological and Vision Sciences. My laboratory is the only molecular biology lab in the College and our research focus is on understanding the role of microRNAs in retinal glial function with the overall goal - to fight blindness.

I was a recipient of a Research Fellowship from the German Research Foundation (DFG, 2014-2016) and the SUNY Empire Innovation Grant (2018-2022). Since 2022 my research has been funded by the NIH (R01EY032532).

email: rhumphrey@sunyopt.edu

Alumnis

Konstantin Hahne, Master’s student (Optometry), Berliner Hochschule für Technik

Eik Bruns, Master’s student (Optometry), Berliner Hochschule für Technik, DAAD stipend recipient

T-35 and SUNY SUMMER STIPEND RECIPIENTS

Maxine Humphrey, O.D. cand., SUNY-Optometry (Summer 2024)

Faiz Khan, O.D. cand., SUNY-Optometry (Summer 2024)

Julia Jager O.D. cand., SUNY-Optometry (summer 2023)

Alexander Rief O.D. cand., SUNY-Optometry (summer 2022)

Quynh Nguyen O.D. cand., UC Berkeley School of Optometry (summer 2019)

Join us!

Are you interested in becoming part of our team? We are currently seeking a highly motivated team member with a strong molecular biology/genetics background. Interns/trainees with interest in cellular and molecular vision science are also very welcome to join our lab!

For more info about the PhD student programs see https://www.sunyopt.edu/education/admissions/graduate_programs

For general inquiries, please use the contact form below. For an application, please sent your letter and detailed CV to swohl@sunyopt.edu.

location

The State University of New York

College of Optometry

Department of Biological and Vision Sciences

33W 42nd Street 10036, New York, NY

Email: swohl@sunyopt.edu

Phone office: +1 212 938 4069

Phone lab: +1 212 938 5822

Publications

1. Kang, S and Wohl, S.G., 2022. Primary Cell Cultures to Study the Regeneration Potential of Murine Müller Glia after MicroRNA Treatment. J Vis Exp. (JoVE), DOI: 10.3791/63651

2. Wohl, S.G. 2022. View in microRNAs as a potential tool to fight blindness: focus on Müller glia and gliosis, invited perspective, Neural Regeneration Research, 17(7): 1501-1502.

3. Kang, S, Larbi, D., Andrade M., Reardon, S., Reh, T.A., Wohl, S.G., 2020. A comparative analysis of reactive Müller glia gene expression after light damage and microRNA-depleted Müller glia – focus on microRNAs, Front Cell Dev Biol 8. doi: 10.3389/fcell.2020.620459

4. VandenBosch L.A., Wohl, S.G., Wilken, M.S. Cox, K., Chipman, L., Reh. T.A., 2020: Cis-Regulatory Accessibility Directs Muller Glial Development and Regenerative Capacity, Scientific Reports 10 (1) 13615. doi: 10.1038/s41598-020-70334-1

5. Wohl, S.G., Hooper, M. J., Reh, T. A., 2019: MicroRNAs miR-25, let-7 and miR-124 regulate the neurogenic potential of Müller glia in mice. Development, 146, dev179556. doi:10.1242/dev.179556.

6. Zuzic, M, Rojo Arias, J. E., Wohl, S. G., Busskamp, V., 2019: Retinal miRNA functions in health and disease. Genes, 10 (5), 377; doi.org/10.3390/genes10050377

7. Schultz, R., Krug, M., Precht, M., Wohl, S.G., Witte, O.W., Schmeer, C., 2018: Frataxin overexpression in Müller cells protects retinal ganglion cells in a mouse model of ischemia/reperfusion injury in vivo. Scientific Reports 8, doi:10.1038/s41598-018-22887-5.

8. Wohl, S. G., Jorstad, N. L., Levine, E., and Reh, T.A., 2017: Müller glial microRNAs are required for the maintenance of glial homeostasis and retinal architecture. Nature Communications, 8(1):1603. doi: 10.1038/s41467-017-01624-y.

9. Jorstad, N. L., Wilken, M. S., Grimes, W. N., Wohl, S. G., VandenBosch L., Yoshimatsu T., Wong R. O., Rieke F., and Reh, T.A., 2017: Stimulation of functional neuronal regeneration from Müller glia in adult mice. Nature 548, 103-107, doi: 10.1038/nature23283.

10. Wohl, S. G. and Reh, T.A., 2016. The microRNAs expression profile of mouse Müller glia in vivo and in vitro. Scientific Reports 6, 35423; doi 10.1038/srep35423.

11. Wohl, S. G. and Reh, T.A., 2016. miR-124-9-9* potentiates Ascl1-induced reprogramming of cultured Müller glia. Glia 64, 743-762.

12. Wohl, S. G., Schmeer, C. W., and Isenmann, S., 2012. Neurogenic potential of stem/progenitor-like cells in the adult mammalian eye. Progress in Retinal and Eye Research 31, 213-242.

13. Schmeer, C. W., Wohl, S. G., and Isenmann, S., 2012. Cell-replacement therapy and neural repair in the retina. Cell and Tissue Research 349, 363-374.

14. Wohl, S. G., Schmeer, C. W., Friese, T., Witte, O. W., and Isenmann, S., 2011. In situ dividing and phagocytosing retinal microglia express Nestin, Vimentin, and NG2 in vivo. PLoSOne 6, e22408.

15. Wohl, S. G., Schmeer, C. W., Witte, O. W., and Isenmann, S., 2010. Proliferative response of microglia and macrophages in the adult mouse eye after optic nerve lesion. Investigative Ophthalmology & Visual Science 51, 2686-2696.

16. Wohl, S. G., Schmeer, C. W., Kretz, A., Witte, O. W., and Isenmann, S., 2009. Optic nerve lesion increases cell proliferation and Nestin expression in the adult mouse eye in vivo. Experimental Neurology 219, 175-186.

Books

“Neuroscience and Biobehavioral Psychology” Chapter “Müller glia Development”  Wohl S.G., Editor in Chief: Patricia d’Amore, Section Editor: Nadean Brown. Section Title: Ocular Development. https://doi.org/10.1016/B978-0-443-13820-1.00126-2

"Molecular Therapies for Inherited Retinal Diseases" Chapter “Retinal miRNA functions in health and disease.” Zuzic M., Rojo Arias J. E., Wohl S.G., and Busskamp V., reprint. https://doi.org/10.3390/books978-3-03943-177-9, ISBN 978-3-03943-176-2 (Hbk); ISBN 978-3-03943-177-9 (PDF), published: October 2020