AAV2-PDE6B restores retinal structure and function in the retinal degeneration 10 mouse model of retinitis pigmentosa by promoting phototransduction and inhibiting apoptosis

Retinitis pigmentosa is a group of inherited diseases that lead to retinal degeneration and photoreceptor cell death.However,there is no effective treatment for retinitis pigmentosa caused by PDE6B mutation.Adeno-associated virus(AAV)-mediated gene therapy is a promising strategy for treating retinitis pigmentosa.The aim of this study was to explore the molecular mechanisms by which AAV2-PDE6B rescues retinal function.To do this,we injected retinal degeneration 10(rd10)mice subretinally with AAV2-PDE6B and assessed the therapeutic effects on retinal function and structure using dark-and light-adapted electroretinogram,optical coherence tomography,and immunofluorescence.Data-independent acquisition-mass spectrometry-based proteomic analysis was conducted to investigate protein expression levels and pathway enrichment,and the results from this analysis were verified by real-time polymerase chain reaction and western blotting.AAV2-PDE6B injection significantly upregulated PDE6βexpression,preserved electroretinogram responses,and preserved outer nuclear layer thickness in rd10 mice.Differentially expressed proteins between wild-type and rd10 mice were closely related to visual perception,and treating rd10 mice with AAV2-PDE6B restored differentially expressed protein expression to levels similar to those seen in wild-type mice.Kyoto Encyclopedia of Genes and Genome analysis showed that the differentially expressed proteins whose expression was most significantly altered by AAV2-PDE6B injection were enriched in phototransduction pathways.Furthermore,the phototransductionrelated proteins Pde6α,Rom1,Rho,Aldh1a1,and Rbp1 exhibited opposite expression patterns in rd10 mice with or without AAV2-PDE6B treatment.Finally,Bax/Bcl-2,p-ERK/ERK,and p-c-Fos/c-Fos expression levels decreased in rd10 mice following AAV2-PDE6B treatment.Our data suggest that AAV2-PDE6B-mediated gene therapy promotes phototransduction and inhibits apoptosis by inhibiting the ERK signaling pathway and upregulating Bcl-2/Bax expression in retinitis pigmentosa.

EXTRAOCULAR CELLULAR PHOTOTRANSDUCTION

Photobiomodulation(PBM)is a modulation of monochromatic light or laser irradiation(LI)on biosystems.It is reviewed from the viewpoint of extraocular phototransduction in this paper.It was found that LI can induce extraocular phototransduction,and there may be an exact correspondence relationship of LI at different wavelengths and in different dose zones,and cellular signal transduction pathways.The signal transduction pathways can be classified into two types so that the Gs protein-mediated pathways belong to pathway 1,and the other pathways such as protein kinase Cs-mediated pathways and mitogen-activated protein kinase-mediated pathways belong to pathway 2.Almost all the present pathways found to mediate PBM belong to pathway 2,but there should be a pathway 1-mediated PBM.The previous studies were rather preliminary,and therefore further work should be done.

Evaluating the Signal Processing Capacities of Post-Mortem Cerebral Cortical Tissue by Artificial Phototransduction of Dynamic Visual Stimuli

The signal processing function of human cerebral cortical tissues is determined by the regional cytoarchitectures distributed throughout the brain. Based upon this assumption, we pursued the hypothesis that residual microstructure within the primary and associative visual cortices of a fixed, post-mortem whole human brain would process electrical signals differentially. To this end, we designed and engineered a very simple brain-photocell interface. Photostimuli, presented as either periodic flashes or as dynamic visual images, were transduced by photocells attached to the optic nerve of a post-mortem human brain specimen. The novel approach revealed that microvolt fluctuations within the primary and associative visual cortices could be discriminated. Simple light-dark discrimination was noted for the primary visual area (BA17) whereas within the right occipito-parietal cortices of the dorsal visual stream (BA19, BA7), spectral power of microvolt fluctuations could discriminate moving visual stimuli from those which were non-moving. Discriminant analysis classified movement represented within the right parietal lobe with 80% success. Together, the results suggest that artificially generated electrical signals are processed differentially by alternative cortical regions in the post-mortem brain.

Mepanipyrim induces visual developmental toxicity and vision-guided behavioral alteration in zebrafish larvae

Mepanipyrim,an anilinopyrimidine fungicide,has been extensively used to prevent fungal diseases in fruit culture.Currently,research on mepanipyrim-induced toxicity in organisms is still very scarce,especially visual developmental toxicity.Here,zebrafish larvae were employed to investigate mepanipyrim-induced visual developmental toxicity.Intense light andmonochromatic light stimuli-evoked escape experiments were used to investigate vision-guided behaviors.Meanwhile,transcriptomic sequencing and real-time quantitative PCR assays were applied to assess the potential mechanisms of mepanipyrim-induced visual developmental toxicity and vision-guided behavioral alteration.Our results showed that mepanipyrim exposure could induce retinal impairment and vision-guided behavioral alteration in larval zebrafish.In addition,the grk1b gene of the phototransduction signaling pathway was found to be a potential aryl hydrocarbon receptor(AhR)-regulated gene.Mepanipyrim-induced visual developmental toxicity was potentially related to the AhR signaling pathway.Furthermore,mepanipyrim-induced behavioral alteration was guided by the visual function,and the effects of mepanipyrim on long and middle wavelength light-sensitive opsins may be the main cause of vision-guided behavioral alteration.Our results provide insights into understanding the relationship between visual development and vision-guided behaviors induced by mepanipyrim exposure.

Upregulation of the PPAR signaling pathway and accumulation of lipids are related to the morphological and structural transformation of the dragon-eye goldfish eye

Goldfish comprise around 300 different strains with drastically altered and aesthetical morphologies making them suitable models for evolutionary developmental biology.The dragon-eye strain is characterized by protruding eyes(analogous to those of Chinese dragons).Although the strain has been selected for about 400 years,the mechanism of its eye development remains unclear.In this study,a stable dragon-eye goldfish strain with a clear genetic background was rapidly established and studied.We found that upregulation of the PPAR signaling pathway accompanied by an increase in lipid accumulation might trigger the morphological and structural transformation of the eye in dragon-eye goldfish.At the developmental stage of proptosis(eye protrusion),downregulation of the phototransduction pathway was consistent with the structural defects and myopia of the dragon-eye strain.With the impairment of retinal development,cytokine-induced inflammation was activated,especially after proptosis,similar to the pathologic symptoms of many human ocular diseases.In addition,differentially expressed transcription factors were significantly enriched in the PAX and homeobox families,two well-known transcription factor families involved in eye development.Therefore,our findings reveal the dynamic changes in key pathways during eye development in dragon-eye goldfish,and provide insights into the molecular mechanisms underlying drastically altered eyes in goldfish and human ocular disease.