The role of microRNAs in Müller glia reprogramming into neurons in the postnatal murine retina: cellular analysis in vitro and in vivo
Ophthalmology
Evolutionary Cell and Developmental Biology (Zoology)
Final Report Abstract
The overall goal of the proposed studies was to evaluate the role of microRNAs (miRNAs) in Müller glia development and cell state (including function), after damage, and in reprogramming/regeneration processes. In order to reveal that role, this project was based on two strategies: 1. testing promising candidates, which have been reported to be involved in neuronal reprogramming and retinal regeneration in other systems, i.e. the miRNAs let-7 and miR-124 and 2. RNA-profiling in order to reveal presence and quantity of Müller glia miRNAs, and to find possible new candidates for Müller glia reprogramming Taken together, this project was very successful. We were able to reveal the miRNA profile for young and mature Müller glia, retinal progenitors, as well as retinal neurons. For the first time, we assigned certain miRNAs to be Müller glia-specific and showed that these miRNAs decline when Müller glia were cultured. This is of high importance since most basic experience, not only for retinal glia but also for those in the brain, are mostly carried out in vitro first before transferred in vivo, or are even exclusively performed in vitro. In addition, we found that miRNAs are required for proper Müller glia function and maintenance. The loss of Dicer in young Müller glia leads to a proliferative and migratory phenotype, similar as the phenotype in fish regeneration, which is however rarely observed in mice, not even after injury. Moreover, the loss of miRNAs also leads eventually to Müller glia death as observed 30 weeks after Dicer the enzyme that generates mature miRNAs deletion, confirming that miRNAs are required for important cellular processes. We also profiled the miRNAs after light damage in order to reveal mechanisms different from the fish regeneration after injury, which is still in progress. Moreover, although we were not able to show regeneration via the let-7/Lin-28/Ascl1 pathway in murine Müller glia, which is one of the fundamental pathways in fish regeneration, we were capable to successfully reprogram Müller glia into neurons by means of miRNAs (miR-124-9-9*), an attempt that has only been reported for fibroblasts so far. Although the reprogramming efficiency was rather low, co-expression of Ascl1 facilitated this conversion into neurons, which was higher than just with Ascl1 alone. The analysis of the progenitor miRNAs, which is also in progress, will additionally reveal potential candidates for Müller glia reprogramming which might have an impact on retinal regeneration. Taken together, we state that miRNAs are crucial for Müller glia development and function and moreover, can be used for glial reprogramming into neurons.
Publications
- The Role of miR-124-9-9* in Müller glia reprogramming. Program No. 681. 2014 Neuroscience Meeting Planner. Washington DC, USA: Society for Neuroscience, 2014
S. G. Wohl, K. Cox, J. Pollak, A. LaTorre, T. A. Reh
- 2016. miR-124-9-9* potentiates Ascl1-induced reprogramming of cultured Müller glia. Glia 64, 743-762
Wohl, S. G. and Reh, T.A.
(See online at https://doi.org/10.1002/glia.22958) - 2016. The microRNAs expression profile of mouse Müller glia in vivo and in vitro. Scientific Reports 6, 35423
Wohl, S. G. and Reh, T.A.
(See online at https://doi.org/10.1038/srep35423) - Changes in microRNAs after injury and Dicer deletion. Program No 4190- D0209, ARVO meeting planner. Seattle, USA, ARVO 2016
S. G. Wohl and T. A. Reh
- Dicer conditional knock out in mature Müller glia leads to upregulation of Brevican and disorganization of the retina structure. Program No. 127, 2016 Neuroscience Meeting Planner. San Diego, USA: Society for Neuroscience, 2016
S. G. Wohl, and T. A. Reh
