查看更多>>摘要：Subretinal fibrosis is a major cause of the poor visual prognosis for patients with neovascular age-related macular degeneration(nAMD).Myofibroblasts originated from retinal pigment epithelial(RPE)cells through epithelial-mesenchymal transition(EMT)contribute to the fibrosis formation.N6-Methyladenosine(m6A)modification has been implicated in the EMT process and multiple fibrotic diseases.The role of m6A modification in EMT-related subretinal fibrosis has not yet been elucidated.In this study,we found that during subretinal fibrosis in the mouse model of laser-induced choroidal neovascularization,METTL3 was upregulated in RPE cells.Through m6Aepitranscriptomic microarray and further verification,high-mobility group AT-hook 2(HMGA2)was identified as the key downstream target of METTL3,subsequently activating potent EMT-inducing transcription factor SNAIL.Finally,by subretinal injections of adeno-associated virus vectors,we confirmed that METTL3 deficiency in RPE cells could efficiently attenuate subretinal fibrosis in vivo.In conclusion,our present research identified an epigenetic mechanism of METTL3-m6A-HMGA2 in subretinal fibrosis and EMT of RPE cells,providing a novel therapeutic target for subretinal fibrosis secondary to nAMD.
查看更多>>摘要：Exercise intervention at the early stage of type 2 diabetes mellitus(T2DM)can aid in the maintenance of blood glucose homeostasis and prevent the development of macrovascular and microvascular complications.However,the exercise-regulated pathways that prevent the development of T2DM remain largely unclear.In this study,two forms of exercise intervention,treadmill training and voluntary wheel running,were conducted for high-fat diet(HFD)-induced obese mice.We observed that both forms of exercise intervention alleviated HFD-induced insulin resistance and glucose intolerance.Skeletal muscle is recognized as the primary site for postprandial glucose uptake and for responsive alteration beyond exercise training.Metabolomic profiling of the plasma and skeletal muscle in Chow,HFD,and HFD-exercise groups revealed robust alterations in metabolic pathways by exercise intervention in both cases.Overlapping analysis identified nine metabolites,including beta-alanine,leucine,valine,and tryptophan,which were reversed by exercise treatment in both the plasma and skeletal muscle.Transcriptomic analysis of gene expression profiles in the skeletal muscle revealed several key pathways involved in the beneficial effects of exercise on metabolic homeostasis.In addition,integrative transcriptomic and metabolomic analyses uncovered strong correlations between the concentrations of bioactive metabolites and the expression levels of genes involved in energy metabolism,insulin sensitivity,and immune response in the skeletal muscle.This work established two models of exercise intervention in obese mice and provided mechanistic insights into the beneficial effects of exercise intervention on systemic energy homeostasis.
查看更多>>摘要：SARS-CoV-2,the coronavirus that causes the disease COVID-19,has claimed millions of lives over the past 2 years.This demands rapid development of effective therapeutic agents that target various phases of the viral replication cycle.The interaction between host transmembrane serine protease 2(TMPRSS2)and viral SPIKE protein is an important initial step in SARS-CoV-2 infection,offering an opportunity for therapeutic development of viral entry inhibitors.Here,we report the development of a time-resolved fluorescence/Förster resonance energy transfer(TR-FRET)assay for monitoring the TMPRSS2-SPIKE interaction in lysate from cells co-expressing these proteins.The assay was configured in a 384-well-plate format for high-throughput screening with robust assay performance.To enable large-scale compound screening,we further miniaturized the assay into 1536-well ultrahigh-throughput screening(uHTS)format.A pilot screen demonstrated the utilization of the assay for uHTS.Our optimized TR-FRET uHTS assay provides an enabling platform for expanded screening campaigns to discover new classes of small-molecule inhibitors that target the SPIKE and TMPRSS2 protein-protein interaction.
查看更多>>摘要：YPEL5 is a member of the Yippee-like(YPEL)gene family that is evolutionarily conserved in eukaryotic species.To date,the physiological function of YPEL5 has not been assessed due to a paucity of genetic animal models.Here,using CRISPR/Cas9-mediated genome editing,we generated a stable ypel5-/-mutant zebrafish line.Disruption of ypel5 expression leads to liver enlargement associated with hepatic cell proliferation.Meanwhile,hepatic metabolism and function are dysregulated in ypel5-/-mutant zebrafish,as revealed by metabolomic and transcriptomic analyses.Mechanistically,Hnf4a is identified as a crucial downstream mediatorthat is positively regulated by Ypel5.Zebrafish hnf4a overexpression could largely rescue ypel5 deficiency-induced hepatic defects.Furthermore,PPARα signaling mediates the regulation of Hnf4a by Ypel5 through directly binding to the transcriptional enhancer of the Hnf4a gene.Herein,this work demonstrates an essential role of Ypel5 in hepatocyte proliferation and function and provides the first in vivo evidence for a physiological role of the ypel5 gene in vertebrates.
查看更多>>摘要：The SARS-CoV-2 spike protein contains a functionally important fatty acid(FA)binding site,which is also found in some other coronaviruses,e.g.SARS-CoV and MERS-CoV.The occupancy of the FA site by linoleic acid(LA)reduces infectivity by'locking'the spike in a less infectious conformation.Here,we use dynamical-nonequilibrium molecular dynamics(D-NEMD)simulations to compare the allosteric responses of spike variants to LA removal.D-NEMD simulations show that the FA site is coupled to other functional regions of the protein,e.g.the receptor-binding motif(RBM),N-terminal domain(NTD),furin cleavage site,and regions surrounding the fusion peptide.D-NEMD simulations also identify the allosteric networks connecting the FA site to these functional regions.The comparison between the wild-type spike and four variants(Alpha,Delta,Delta plus,and Omicron BA.1)shows that the variants differ significantly in their responses to LA removal.The allosteric connections to the FA site on Alpha are generally similar to those on the wild-type protein,with the exception of the RBM and the S71-R78 region,which show a weaker link to the FA site.In contrast,Omicron is the most different variant,exhibiting significant differences in the RBM,NTD,V622-L629,and furin cleavage site.These differences in the allosteric modulation may be of functional relevance,potentially affecting transmissibility and virulence.Experimental comparison of the effects of LA on SARS-CoV-2 variants,including emerging variants,is warranted.
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