Biology subjects

Fogerty, J.

Publications and source records attributed to Fogerty, J..

3 recordsLinked to original sources

bioRxiv2021

Notch inhibition promotes regeneration and immunosuppression supports cone survival in a zebrafish model of inherited retinal dystrophy

Photoreceptor degeneration leads to irreversible vision loss in humans with retinal dystrophies such as Retinitis Pigmentosa. Whereas photoreceptor loss is permanent in mammals, zebrafish possesses the ability to regenerate retinal neurons and restore visual function. Following acute damage, Muller glia (MG) re-enter the cell cycle and produce multipotent progenitors whose progeny differentiate into mature neurons. Both MG reprogramming and proliferation of retinal progenitor cells require reactive microglia and associated inflammatory signaling. Paradoxically, MG in zebrafish models of photoreceptor degeneration fail to re-enter the cell cycle and regenerate lost cells. Here, we used the zebrafish cep290 mutant to demonstrate that progressive cone degeneration generates an immune response but does not stimulate MG proliferation. Acute light damage triggered photoreceptor regeneration in cep290 mutants but cones were only restored to pre-lesion densities. Using irf8 mutant zebrafish, we found that the chronic absence of microglia reduced inflammation and rescued cone degeneration in cep290 mutants. Finally, single-cell RNA-sequencing revealed sustained expression of notch3 in MG of cep290 mutants and inhibition of Notch signaling induced MG to re-enter the cell cycle. Our findings provide new insights on the requirements for MG to proliferate and the potential for immunosuppression to prolong photoreceptor survival.

neuroscience↗

bioRxiv2020

Mutations in BBS2 Cause Apparent Nonsyndromic Retinitis Pigmentosa

PurposeTo identify and functionally test the causative mutations in the BBS2 gene in a family presenting with retinitis pigmentosa and infertility and to generate a bbs2-/- mutant zebrafish. MethodsA female proband and her male sibling were clinically evaluated and genetic testing with targeted next-generation sequencing was performed. Mutations were verified by Sanger sequencing. Protein localization was examined by transient expression and immunocytochemistry in cultured HEK-293T cells. Mutations in the zebrafish bbs2 gene were generated by CRISPR/Cas9 and retinal phenotypes were examined by immunohistochemistry. ResultsThe proband and her brother exhibited reduced visual fields, retinal degeneration, and bone spicule deposits, consistent with retinitis pigmentosa. The brother also reported symptoms consistent with infertility. Compound heterozygous mutations in the BBS2 gene; namely NM_031885.4 (BBS2):c.823C>T (p.R275X) and NM_031885.4 (BBS2):c.401C>G (p.P134R), were identified in the proband and her brother. Both mutations interfered with ciliary localization of Bbs2 in cell culture. Mutation of the zebrafish bbs2 gene resulted in progressive cone degeneration and rhodopsin mislocalization. ConclusionMissense mutations of BBS2 leads to non-syndromic retinitis pigmentosa, but not Bardet-Biedl Syndrome, even though Bbs2 fails to localize to cilia. In zebrafish, the complete loss of bbs2 results in cone degeneration and ciliopathy phenotypes, indicating a requirement for Bbs2 in photoreceptor survival.

genetics↗

bioRxiv2019

Ciliary Genes arl13b, ahi1 and cc2d2a Differentially Modify Expression of Visual Acuity Phenotypes but do not Enhance Retinal Degeneration due to Mutation of cep290 in Zebrafish

Mutations in the gene Centrosomal Protein 290 kDa (CEP290) result in multiple ciliopathies ranging from the neonatal lethal disorder Meckel-Gruber Syndrome to multi-systemic disorders such as Joubert Syndrome and Bardet-Biedl Syndrome to nonsyndromic diseases like Leber Congenital Amaurosis (LCA) and retinitis pigmentosa. Results from model organisms and human genetics studies, have suggest that mutations in genes encoding protein components of the transition zone (TZ) and other cilia-associated proteins can function as genetic modifiers and be a source for CEP290 pleiotropy. We investigated the zebrafish cep290fh297/fh297 mutant, which encodes a nonsense mutation (p.Q1217*). This mutant is viable as adults, exhibits scoliosis, and undergoes a slow, progressive cone degeneration. The cep290fh297/fh297 mutants showed partial mislocalization of the transmembrane protein rhodopsin but not of the prenylated proteins rhodopsin kinase (GRK1) or the rod transducin subunit GNB1. Surprisingly, photoreceptor degeneration did not trigger proliferation of Muller glia, but proliferation of rod progenitors in the outer nuclear layer was significantly increased. To determine if heterozygous mutations in other cilia genes could exacerbate retinal degeneration, we bred cep290fh297/fh297 mutants to arl13b, ahi1, and cc2d2a mutant zebrafish lines. While cep290fh297/fh297 mutants lacking a single allele of these genes did not exhibit accelerated photoreceptor degeneration, loss of one alleles of arl13b or ahi1 reduced visual performance in optokinetic response assays at 5 days post fertilization. Our results indicate that the cep290fh297/fh297 mutant is a useful model to study the role of genetic modifiers on photoreceptor degeneration in zebrafish and to explore how progressive photoreceptor degeneration influences regeneration in adult zebrafish.\n\nNonstandard abbreviations

cell biology↗