Project description:An early aspect of sepsis is dysregulated activation of endothelial cells (EC), initiating a cascade of inflammatory signaling leading to leukocyte adhesion/migration and organ damage. Therapeutic targeting of ECs has been hampered by concerns regarding ECs heterogeneity from different organs. Using a combination of in vitro and in silico analysis, we present a comprehensive analysis of proteomic changes in mouse lung, kidney and liver ECs following exposure to a clinically relevant cocktail of proinflammatory cytokines. Mouse lung, liver and kidney ECs were incubated with TNFα/IL-1β/IFNγ for 4 or 24 hrs to model inflammatory responses during sepsis. Quantitative label-free global proteomics was performed on the ECs to identify differentially expressed proteins (DEP). Proteins with an abundance ratio >2.0 or <0.5 and an adjusted p<0.05 were characterized as upregulated or downregulated respectively. Gene Ontology (GO) classification was used to determine biological processes that regulate EC function during sepsis and PANTHER was used to classify the molecular function of the identified proteins. Finally, an interactive pathway was developed to investigate signaling within ECs and across organs. Proteomic analysis identified both unique and shared DEPs between the ECs specific to lung, liver and kidney. Using GO, 5 Biological Processes (BP) for each of the organ specific ECs were identified. Interestingly, 4 of the top 5 GO BPs were observed in all 3 ECs at 4 and 24 hrs: defense response to other organism, innate immune response, response to bacterium and response to cytokine. However, these BPs were found to be differentially regulated. For example, at 4 and 24 hrs, lung ECs which have the highest number and highest fold expression of upregulated proteins (189 and 316 respectively), also have higher numbers of unique upregulated proteins (124 vs 194) compared to liver (98 vs 121) and kidney ECs (109 vs 136). The liver showed the greatest number of conserved proteins between 4 and 24 hrs (56) compared to lung (50) and kidney (51). The number of common proteins between all three ECs increases from 38 at 4 hrs to 79 at 24 hrs, indicating more uniformity in ECs proteomic expression during the progression of sepsis. The PANTHER database was used to classify proteins in different functional groups (e.g. defense/immunity) at 4 and 24 hrs. Thus, BPs and PANTHER hits can provide insight into why some organs are more susceptible to sepsis early on and show that as sepsis progresses, some protein expression patterns become more uniform while additional organ specific proteins are expressed. Proteomic analysis of organ-specific ECs provides further understanding of how sepsis affects multiple organs across time and supports future proteomic, temporal studies of EC dysfunction.

Project description:Background: As a widespread post-transcriptional RNA modification, N5-methylcytosine (m5C) is implicated in a variety of cellular responses and processes that regulate RNA metabolism. Despite this, a clear understanding of m5C modification’s role and mechanism in angiogenesis is still lacking. Methods: Single-cell RNA sequencing data was analyzed to determine expression of m5C methylase NSUN2. m5C levels were determined by mRNA isolation and anti-m5C dot blot in both hypoxia-induced endothelial cells (ECs) and laser-induced choroidal neovascularization (CNV). In addition, endothelial cell and endothelium‐specific NSUN2‐knockout mouse model were used to investigate the effect of NSUN2 silence on angiogenic phenotype. Genome-wide multiomics analyses were performed to identify the functional target of NSUN2, including proteomic analysis, transcriptome screening and m5C-methylated RNA immunoprecipitation sequencing (m5C-meRIP-seq). CUT&Tag sequencing was performed to test the histone lactylation signal in the promoter region of NSUN2. Finally, AAV-mediated short hairpin RNAi knockdown of NSUN2 gene expression (AAV-shNSUN2) was constructed to investigate the effect of inhibiting CNV. Results: First, we discovered that m5C methylase NSUN2 expression level and mRNA m5C level were significantly higher in CNV-ECs than in normal ECs. NSUN2 knockdown in ECs inhibited proliferative, migration, and tube formation activities of ECs. Moreover, compared with EC NSUN2flox/flox mice, EC-specific NSUN2-deficient (EC NSUN2-/-) mice displayed less retinal vascular leakage after laser induction. Through multiomics analyses, we subsequently identified A-kinase anchoring protein 2 (AKAP2), a scaffolding protein which isolate Protein kinase A (PKA) to specific subcellular locations through binding to its regulatory subunit, as a downstream candidate target of NSUN2 in ECs. Overexpression of exogenous AKAP2 markedly reversed the inhibitory phenotypes in NSUN2-deficient ECs. Interestingly, laser induced NSUN2 up-regulation was driven by lactate-mediated lactylation on histone H3K18. In CNV models, AAV-mediated repression of NSUN2 modulated highly retinal vascular leakage and choroidal thickness. Conclusion: Overall, our findings indicate that NSUN2 is a novel therapeutic target for choroidal neovascularization.

Dataset Information

Histone lactylation drives endothelial activation-mediated lung injury in sepsis-associated ARDS via promoting ferroptosis

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets