Cell replacement with stem cell-derived retinal ganglion cells from different protocols

Glaucoma,characterized by a degenerative loss of retinal ganglion cells,is the second leading cause of blindness worldwide.There is currently no cure for vision loss in glaucoma because retinal ganglion cells do not regenerate and are not replaced after injury.Human stem cell-derived retinal ganglion cell transplant is a potential therapeutic strategy for retinal ganglion cell degenerative diseases.In this review,we first discuss a 2D protocol for retinal ganglion cell differentiation from human stem cell culture,including a rapid protocol that can generate retinal ganglion cells in less than two weeks and focus on their transplantation outcomes.Next,we discuss using 3D retinal organoids for retinal ganglion cell transplantation,comparing cell suspensions and clusters.This review provides insight into current knowledge on human stem cell-derived retinal ganglion cell differentiation and transplantation,with an impact on the field of regenerative medicine and especially retinal ganglion cell degenerative diseases such as glaucoma and other optic neuropathies.

Photobiomodulation for the treatment of retinal diseases: a review

Photobiomodulation（PBM）,also known as low level laser therapy,has recently risen to the attention of the ophthalmology community as a promising new approach to treat a variety of retinal conditions including agerelated macular degeneration,retinopathy of prematurity,diabetic retinopathy,Leber’s hereditary optic neuropathy,amblyopia,methanol-induced retinal damage,and possibly others.This review evaluates the existing research pertaining to PBM applications in the retina,with a focus on the mechanisms of action and clinical outcomes.All available literature until April 2015 was reviewed using Pub Med and the following keywords：＂photobiomodulation AND retina＂,＂low level light therapy AND retina＂,＂low level laser therapy AND retina＂,and＂FR/NIR therapy AND retina＂.In addition,the relevant references listed within the papers identified through Pub Med were incorporated.The literature supports the conclusion that the low-cost and noninvasive nature of PBM,coupled with the first promising clinical reports and the numerous preclinical-studies in animal models,make PBM well-poised to become an important player in the treatment of a wide range of retinal disorders.Nevertheless,large-scale clinical trials will be necessary to establish the PBM therapeutic ranges for the various retinal diseases,as well as to gain a deeper understanding of its mechanisms of action.

Compartmentalization of local cAMP signaling in neuronal growth and survival

Intracellular signal transduction controlling neuronal development and survival is conveyed by second messengers that are often differentially regulated over space and time.The highly polarized morphology of neurons is conferred by a network of regulatory signaling pathways that determine axon guidance and dendrite formation.Among these,cyclic adenosine monophosphate(cAMP)is a second messenger that is critical for numerous neuronal functions and known to activate and integrate a variety of downstream pathways.In the central nervous system(CNS),cAMP-dependent signaling is involved in growth cone motility,neuronal metabolism,axon extension in vitro,neuroprotection,and survival in vivo.The complexity of cAMP-dependent neuronal physiology and function raises fundamental questions about the mechanisms determining the specificity by which cAMP can regulate these processes.

Identification and validation of key biomarkers and potential therapeutic targets for primary open-angle glaucoma

Primary open-angle glaucoma(POAG)is a prevalent cause of blindness worldwide,resulting in degeneration of retinal ganglion cells and permanent damage to the optic nerve.However,the underlying pathogenetic mechanisms of POAG are currently indistinct,and there has been no effective nonsurgical treatment regimen.The objective of this study is to identify novel biomarkers and potential therapeutic targets for POAG.The mRNA expression microarray datasets GSE27276 and GSE138125,as well as the single-cell high-throughput RNA sequencing(sc RNA-seq)dataset GSE148371 were utilized to screen POAGrelated differentially expressed genes(DEGs).Functional enrichment analyses,protein-protein interaction(PPI)analysis,and weighted gene co-expression network analysis(WGCNA)of the DEGs were performed.Subsequently,the hub genes were validated at a single-cell level,where trabecular cells were annotated,and the mRNA expression levels of target genes in different cell clusters were analyzed.Immunofluorescence and quantitative real-time PCR(q PCR)were performed for further validation.DEGs analysis identified 43 downregulated and 32 upregulated genes in POAG,which were mainly enriched in immune-related pathways,oxidative stress,and endoplasmic reticulum(ER)stress.PPI networks showed that FN1 and DUSP1 were the central hub nodes,while GPX3 and VAV3 were screened out as hub genes through WGCNA and subsequently validated by q PCR.Finally,FN1,GPX3,and VAV3 were determined to be pivotal core genes via single-cell validation.The relevant biomarkers involved in the pathogenesis of POAG,may serve as potential therapeutic targets.Further studies are necessary to unveil the mechanisms underlying the expression variations of these genes in POAG.

Laboratory evaluation of higher-order aberrations and light scattering in explanted opacified intraocular lenses

Background:Intraocular lens(IOL)calcification is a serious condition that can only be treated by removing the clouded lens.Since explantation bears the risk of complications,it is often deferred until the patient finds the symptoms intolerable.Usually,as the IOL opacifies,visual acuity is minimally affected early on.In this study,we assessed the impact of IOL opacification on optical quality.Methods:We analyzed ten opacified explanted IOLs(Oculentis GmbH).Wavefront aberrations were obtained with a SHSOphthalmic device(Optocraft GmbH),which features a Hartmann-Shack sensor.The root mean square(RMS)of higher-order aberrations(HOAs)was compared.The effect of calcification on image quality was assessed through the Strehl ratio(SR).We detected light scattering with a C-Quant(Oculus GmbH)and expressed it as a straylight parameter.Results:At 2 mm,3mm and 4 mm,the mean RMS(±standard deviation)was 0.033μm(±0.026μm),0.044μm(±0.027),and 0.087μm(±0.049),respectively.The mean SR value was 0.81±0.15 at 3 mm,with four IOLs showing a nearly diffraction-limited performance,but in two explants,opacification precluded reliable measurements.Increased straylight was found in all opacified IOLs with a mean value of 150.2±56.3 deg^(2)/sr at 3 mm.Conclusions:We demonstrated that IOL opacification induces HOAs.However,the RMS remained low,which resulted only in a slight reduction of the SR-derived optical quality.On the other hand,we found a severe straylight elevation in the opacified lenses,which may result in dysphotopsia,such as glare,and subjective complaints,despite good visual acuity.

Questions about NgAgo

Dear Editor： Gao et al. published data in Nature Biotechnology （Nat Biotechnol. 2016 May 2） showing that DNA-guided genome editing using the Natronobacterium gregoryi Argonaute （NgAgo） protein targeted 47 mammalian genomic loci with a 100% success rate and an efficiency of 21.3%-41.3% at various targets. This report led us to test NgAgo＇s utility in various cells and organisms such as mouse and zebrafish for gene editing.

Erratum to： Questions about NgAgo

In the original publication of this article the Figure 1E legend has been incorrectly published.

Single-cell transcriptomic Atlas of aging macaque ocular outflow tissues

The progressive degradation in the trabecular meshwork(TM)is related to age-related ocular diseases like primary open-angle glaucoma.However,the molecular basis and biological significance of the aging process in TM have not been fully elucidated.Here,we established a dynamic single-cell transcriptomic landscape of aged macaque TM,wherein we classified the outflow tissue into 12 cell subtypes and identified mitochondrial dysfunction as a prominent feature of TM aging.Furthermore,we divided TM cells into 13 clusters and performed an in-depth analysis on cluster O,which had the highest aging score and the most significant changes in cell proportions between the two groups.Ultimately,we found that the APOE gene was an important differentially expressed gene in cluster O during the aging process,highlighting the close relationship between cell migration and extracellular matrix regulation,and TM function.Our work further demonstrated that silencing the APOE gene could increase migration and reduce apoptosis by releasing the inhibition on the PI3K-AKT pathway and downregulating the expression of extracellular matrix components,thereby increasing the aqueous outflow rate and maintaining intraocular pressure within the normal range.Our work provides valuable insights for future clinical diagnosis and treatment of glaucoma.