scholarly journals Cannabinoid signaling promotes the reprogramming of Muller glia into proliferating progenitor cells.

2021 ◽  
Author(s):  
Warren Campbell ◽  
Sydney Blum ◽  
Alana Reske ◽  
Thanh Hoang ◽  
Seth Blackshaw ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Expression Patterns ◽  
Synaptic Function ◽  
Muller Glia ◽  
Müller Glia ◽  
Rna Seq ◽  
Retinal Neurons ◽  
Pharmacological Agents ◽  
Retinal Microglia ◽  
Glial Reactivity

Endocannabinoids (eCB) are lipid-based neurotransmitters that are known to influence synaptic function in the visual system. eCBs are also known to suppress neuroinflammation in different pathological states. However, nothing is known about the roles of the eCB system during reprogramming of Müller glia (MG) into proliferating progenitor-like cells in the retina. Accordingly, we used the chick and mouse model to characterize expression patterns of eCB-related genes and applied pharmacological agents to examine how the eCB system impacts glial reactivity and the capacity of MG to become Müller glia-derived progenitor cells (MGPCs). We probed single cell RNA-seq libraries to identify eCB-related genes and identify cells with dynamic patterns of expression in damaged retinas. MG and inner retinal neurons expressed the eCB receptor CNR1, as well as enzymes involved in eCB metabolism. In the chick, intraocular injections of 2-Arachidonoylglycerol (2-AG) and Anandamide (AEA) potentiated the formation of MGPCs. Consistent with these findings, CNR1-agonists and MGLL-inhibitor promoted reprogramming, whereas CNR1-antagonist and inhibitors of eCB synthesis suppressed reprogramming. Surprisingly, retinal microglia were largely unaffected by increases or decreases in eCB signaling in both chick and mouse models. However, eCB-signaling suppressed the activation of NFkB-reporter in MG in damaged mouse retinas. We conclude that the eCB system in the retina influences the reactivity of MG and is important for regulating glial reactivity and the reprogramming of MG into proliferating MGPCs, but not for regulating the reactivity of immune cells in the retina.

scholarly journals Midkine in chick and mouse retinas: neuroprotection, glial reactivity and the formation of Müller glia-derived progenitor cells

2020 ◽  
Author(s):  
Warren A. Campbell ◽  
Amanda Fritsch-Kelleher ◽  
Isabella Palazzo ◽  
Thanh Hoang ◽  
Seth Blackshaw ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Neuronal Survival ◽  
Expression Patterns ◽  
Model Systems ◽  
Muller Glia ◽  
Heparin Binding ◽  
Müller Glia ◽  
Related Factors ◽  
Neuroprotective Effects ◽  
Dying Cells

AbstractRecent studies have shown that midkine (MDK), a basic heparin-binding growth factor, is involved in the development and regeneration of the zebrafish retina. However, very little is known about MDK in the retinas of warm-blooded vertebrates. We investigate the expression patterns of MDK and related factors, roles in neuronal survival, and influence upon the formation of Müller glia-derived progenitor cells (MGPCs) in chick and mouse model systems. By using single-cell RNA-sequencing, we find that MDK is upregulated during Müller glia (MG) maturation in chick development and when stimulated to reprogram into MGPCs after NMDA damage or FGF2/Insulin treatment. Interestingly, MDK is significantly up-regulated by MG in damaged chick retinas, but down-regulated by MG in damaged mouse retinas. In both chick and mouse retinas, exogenous MDK selectively up-regulates cFOS and pS6 (a readout of mTOR-signaling) in MG. In the chick, intraocular injections of MDK before injury is neuroprotective with an observed decrease in dying neurons and microglial reactivity, inducing fewer proliferating MGPCs. Blocking MDK signaling with Na3VO4 following blocks neuroprotective effects with an increase the number of dying cells and negates the pro-proliferative effects on MGPCs. Inhibitors of PP2A and Pak1 associated with MDK integrin β1 signaling had MG specific inhibitory effects on MGPC formation. In mice, MDK administration with NMDA damage drives a small but significant increase in MGPCs. We conclude that MDK expression is dynamically regulated in reactive Müller glia and during reprogramming into MGPCs. MDK acts to coordinate glial activity, neuronal survival, and may act in an autocrine manner to influence the re-programming of Müller glia into proliferating MGPCs.

scholarly journals Midkine is neuroprotective and influences glial reactivity and the formation of Müller glia‐derived progenitor cells in chick and mouse retinas

Glia ◽  
2021 ◽  
Author(s):  
Warren A. Campbell ◽  
Amanda Fritsch‐Kelleher ◽  
Isabella Palazzo ◽  
Thanh Hoang ◽  
Seth Blackshaw ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Muller Glia ◽  
Müller Glia ◽  
Glial Reactivity

scholarly journals Nuclear Factor I in neurons, glia and during the formation of Muller glia-derived progenitor cells in avian, porcine and primate retinas

2021 ◽  
Author(s):  
Heithem El-Hodiri ◽  
Warren Campbell ◽  
Lisa Kelly ◽  
Evan Hawthorn ◽  
Maura Schwartz ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Mouse Retina ◽  
Nuclear Factor ◽  
Muller Glia ◽  
Müller Glia ◽  
Retinal Neurons ◽  
Intrinsic Factors ◽  
Factor I ◽  
Chick Retina ◽  
Nuclear Factor I

The regenerative potential of Müller glia (MG) is extraordinary in fish, poor in chick and terrible in mammals. In the chick model, MG readily reprogram into proliferating Müller glia-derived progenitor cells (MGPCs), but neuronal differentiation is very limited. The factors that suppress the neurogenic potential of MGPCs in the chick are slowly being revealed. Isoforms of Nuclear Factor I (NFI) are cell-intrinsic factors that limit neurogenic potential; these factors are required for the formation of MG in the developing mouse retina (Clark et al., 2019) and deletion of these factors reprograms MG into neuron-like cells in mature mouse retina (Hoang et al., 2020). Accordingly, we sought to characterize the patterns of expression NFIs in the developing, mature and damaged chick retina. In addition, we characterized patterns of expression of NFIs in the retinas of large mammals, pigs and monkeys. Using a combination of single cell RNA-sequencing (scRNA-seq) and immunolabeling we probed for patterns of expression. In embryonic chick, levels of NFIs are very low in early E5 (embryonic day 5) retinal progenitor cells (RPCs), up-regulated in E8 RPCs, further up-regulated in differentiating MG at E12 and E15. NFIs are maintained in mature resting MG, microglia and neurons. Levels of NFIs are reduced in activated MG in retinas treated with NMDA and/or insulin+FGF2, and further down-regulated in proliferating MGPCs. However, levels of NFIs in MGPCs were significantly higher than those seen in RPCs. Immunolabeling for NFIA and NFIB closely matched patterns of expression revealed in different types of retinal neurons and glia, consistent with findings from scRNA-seq. In addition, we find expression of NFIA and NFIB through progenitors in the circumferential marginal zone at the far periphery of the retina. We find similar patterns of expression for NFIs in scRNA-seq databases for pig and monkey retinas. Patterns of expression of NFIA and NFIB were validated with immunofluorescence in pig and monkey retinas wherein these factors were predominantly detected in MG and a few types of inner retinal neurons. In summary, NFIA and NFIB are prominently expressed in developing chick retina and by mature neurons and glia in the retinas of chicks, pigs and monkeys. Although levels of NFIs are decreased in chick, in MGPCs these levels remain higher than those seen in neurogenic RPCs. We propose that the neurogenic potential of MGPCs in the chick retina is suppressed by NFIs.

scholarly journals Reprogramming Müller Glia to Regenerate Retinal Neurons

2020 ◽  
Vol 6 (1) ◽  
pp. 171-193 ◽  
Author(s):  
Manuela Lahne ◽  
Mikiko Nagashima ◽  
David R. Hyde ◽  
Peter F. Hitchcock
Keyword(s):  
Progenitor Cells ◽  
Molecular Mechanisms ◽  
Vision Loss ◽  
Current Knowledge ◽  
Cellular Reprogramming ◽  
Muller Glia ◽  
Müller Glia ◽  
Retinal Neurons ◽  
Age Related

In humans, various genetic defects or age-related diseases, such as diabetic retinopathies, glaucoma, and macular degeneration, cause the death of retinal neurons and profound vision loss. One approach to treating these diseases is to utilize stem and progenitor cells to replace neurons in situ, with the expectation that new neurons will create new synaptic circuits or integrate into existing ones. Reprogramming non-neuronal cells in vivo into stem or progenitor cells is one strategy for replacing lost neurons. Zebrafish have become a valuable model for investigating cellular reprogramming and retinal regeneration. This review summarizes our current knowledge regarding spontaneous reprogramming of Müller glia in zebrafish and compares this knowledge to research efforts directed toward reprogramming Müller glia in mammals. Intensive research using these animal models has revealed shared molecular mechanisms that make Müller glia attractive targets for cellular reprogramming and highlighted the potential for curing degenerative retinal diseases from intrinsic cellular sources.

scholarly journals NF-κB signaling regulates the formation of proliferating Müller glia-derived progenitor cells in the avian retina

Development ◽  
2020 ◽  
Vol 147 (10) ◽  
pp. dev183418 ◽  
Author(s):  
Isabella Palazzo ◽  
Kyle Deistler ◽  
Thanh V. Hoang ◽  
Seth Blackshaw ◽  
Andy J. Fischer
Keyword(s):  
Progenitor Cells ◽  
Muller Glia ◽  
Müller Glia ◽  
Avian Retina

scholarly journals STAT pathway activation limits the Ascl1-mediated chromatin remodeling required for neural regeneration from Müller glia in adult mouse retina

2019 ◽  
Author(s):  
Nikolas L. Jorstad ◽  
Matthew S. Wilken ◽  
Levi Todd ◽  
Paul Nakamura ◽  
Nick Radulovich ◽  
...  
Keyword(s):  
Adult Mouse ◽  
Neural Regeneration ◽  
Mouse Retina ◽  
Binding Motif ◽  
Muller Glia ◽  
Müller Glia ◽  
Rna Seq ◽  
Transgenic Expression ◽  
Pathway Activation ◽  
Stat Pathway

AbstractMüller glia can serve as a source for retinal regeneration in some non-mammalian vertebrates. Recently we found that this process can be induced in mouse Müller glia after injury, by combining transgenic expression of the proneural transcription factor Ascl1 and the HDAC inhibitor TSA. However, new neurons are only generated from a subset of Müller glia in this model, and identifying factors that limit Ascl1-mediated MG reprogramming could potentially make this process more efficient, and potentially useful clinically. One factor that limits neurogenesis in some non-mammalian vertebrates is the STAT pathway activation that occurs in Müller glia in response to injury. In this report, we tested whether injury induced STAT activation hampers the ability of Ascl1 to reprogram Müller glia into retinal neurons. Using a STAT inhibitor, in combination with our previously described reprogramming paradigm, we found a large increase in the ability of Müller glia to generate neurons, similar to those we described previously. Single-cell RNA-seq showed that the progenitor-like cells derived from Ascl1-expressing Müller glia have a higher level of STAT signaling than those that become neurons. Using Ascl1 ChIP-seq and DNase-seq, we found that developmentally inappropriate Ascl1 binding sites (that were unique to the overexpression context) had enrichment for the STAT binding motif. This study provides evidence that STAT pathway activation reduces the efficiency of Ascl1-mediated reprogramming in Müller glia, potentially by directing Ascl1 to inappropriate targets.

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