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ObjectivesWe investigated the role and molecular mechanisms of RNA-binding proteins (RBPs) and their regulated alternative splicing events (RASEs) in the pathogenesis of mitral valve prolapse (MVP). MethodsFor RNA extraction, we obtained peripheral blood mononuclear cells (PBMCs) from five patients with MVP, with or without chordae tendineae rupture, and five healthy individuals. High-throughput sequencing was used for RNA sequencing (RNA-seq). Differentially expressed genes (DEGs) analysis, alternative splicing (AS) analysis, functional enrichment analysis, co-expression of RBPs, and alternative splicing events (ASEs) analysis were conducted.ResultsThe MVP patients exhibited 306 up-regulated genes and 198 down-regulated genes. All down- and up-regulated genes were enriched in both Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Furthermore, MVP was closely associated with the top 10 enriched terms and pathways. In MVP patients, 2,288 RASEs were found to be significantly different, and four suitable RASEs (CARD11 A3ss, RBM5 ES, NCF1 A5SS, and DAXX A3ss) were tested. We identified 13 RNA-binding proteins (RBPs) from the DEGs and screened out four RBPs (ZFP36, HSPA1A, TRIM21, and P2RX7). We selected four RASEs based on the co-expression analyses of RBPs and RASEs, including exon skipping (ES) of DEDD2, alternative 3′ splice site (A3SS) of ETV6, mutually exclusive 3′UTRs (3pMXE) of TNFAIP8L2, and A3SS of HLA-B. Furthermore, the selected four RBPs and four RASEs were validated by reverse transcription–quantitative polymerase chain reaction (RT-qPCR) and showed high consistency with RNA sequencing (RNA-seq).ConclusionDysregulated RBPs and their associated RASEs may play regulatory roles in MVP development and may therefore be used as therapeutic targets in the future.

Neutrophils are the most abundant leukocyte in human blood. They are critical for fighting infections and are involved in inflammatory diseases. Mitochondria are indispensable for eukaryotic cells, as they control the biochemical processes of respiration and energy production. Mitochondria in neutrophils have been underestimated since glycolysis is a major metabolic pathway for fuel production in neutrophils. However, several studies have shown that mitochondria are greatly involved in multiple neutrophil functions as well as neutrophil-related diseases. In this review, we focus on how mitochondrial components, metabolism, and related genes regulate neutrophil functions and relevant diseases.

Vascular endothelial injury caused by post-hemorrhagic shock mesenteric lymph (PHSML) return is an important manifestation during refractory hemorrhagic shock. Using human umbilical vein endothelial cells (HUVECs) and transcriptome analysis, this study sought to investigate the molecular mechanism underlying the adverse effect of PHSML on vascular endothelium. Post-hemorrhagic shock mesenteric lymph was collected from male rats after they underwent hemorrhagic shock and following resuscitation, while normal mesenteric lymph (NML) was harvested from sham rats. Human umbilical vein endothelial cells were incubated with the culture medium containing either 10% phosphate buffered saline (Control), NML, or PHSML for 3 h, and then were harvested for RNA sequencing. In comparison with NML treated cells, 37 genes were differentially expressed in PHSML-treated HUVECs, including 32 upregulated genes and five downregulated genes. These differentially expressed genes were mainly enriched in inflammatory pathways, including signaling pathways for activation of the NOD-like receptors, NF-κB, and TNF. Furthermore, we found that C–C motif chemokine ligand 2 (CCL2) was increased significantly after PHSML treatment, and Bindarit, a CCL2 production inhibitor, attenuated the damage of HUVECs induced by PHSML. The results provide molecular evidence on vascular endothelium damage caused by PHSML. C–C motif chemokine ligand 2 might represent a new target for reducing vascular injury after severe hemorrhagic shock.

As the primary natural barrier that protects against adverse environmental conditions, the skin plays a crucial role in the innate immune response of fish, particularly in relation to bacterial infections. However, due to the diverse functionality and intricate anatomical and cellular composition of the skin, deciphering the immune response of the host is a challenging task. In this study, single nuclei RNA-sequencing (snRNA-seq) was performed on skin biopsies obtained from Chinese longsnout catfish (Leiocassis longirostris), comparing Aeromonas hydrophila-infected subjects to healthy control subjects. A total of 19,581 single nuclei cells were sequenced using 10x Genomics (10,400 in the control group and 9,181 in the treated group). Based on expressed unique transcriptional profiles, 33 cell clusters were identified and classified into 12 cell types including keratinocyte (KC), fibroblast (FB), endothelial cells (EC), secretory cells (SC), immune cells, smooth muscle cells (SMC), and other cells such as pericyte (PC), brush cell (BC), red blood cell (RBC), neuroendocrine cell (NDC), neuron cells (NC), and melanocyte (MC). Among these, three clusters of KCs, namely, KC1, KC2, and KC5 exhibited significant expansion after A. hydrophila infection. Analysis of pathway enrichment revealed that KC1 was primarily involved in environmental signal transduction, KC2 was primarily involved in endocrine function, and KC5 was primarily involved in metabolism. Finally, our findings suggest that neutrophils may play a crucial role in combating A. hydrophila infections. In summary, this study not only provides the first detailed comprehensive map of all cell types present in the skin of teleost fish but also sheds light on the immune response mechanism of the skin following A. hydrophila infection in Chinese longsnout catfish. [ABSTRACT FROM AUTHOR]

Objectives: We investigated the role and molecular mechanisms of RNA-binding proteins (RBPs) and their regulated alternative splicing events (RASEs) in the pathogenesis of mitral valve prolapse (MVP). Methods: For RNA extraction, we obtained peripheral blood mononuclear cells (PBMCs) from five patients with MVP, with or without chordae tendineae rupture, and five healthy individuals. High-throughput sequencing was used for RNA sequencing (RNA-seq). Differentially expressed genes (DEGs) analysis, alternative splicing (AS) analysis, functional enrichment analysis, co-expression of RBPs, and alternative splicing events (ASEs) analysis were conducted. Results: The MVP patients exhibited 306 up-regulated genes and 198 downregulated genes. All down- and up-regulated genes were enriched in both Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Furthermore, MVP was closely associated with the top 10 enriched terms and pathways. In MVP patients, 2,288 RASEs were found to be significantly different, and four suitable RASEs (CARD11 A3ss, RBM5 ES, NCF1 A5SS, and DAXX A3ss) were tested. We identified 13 RNA-binding proteins (RBPs) from the DEGs and screened out four RBPs (ZFP36, HSPA1A, TRIM21, and P2RX7). We selected four RASEs based on the co-expression analyses of RBPs and RASEs, including exon skipping (ES) of DEDD2, alternative 3′ splice site (A3SS) of ETV6, mutually exclusive 3′UTRs (3pMXE) of TNFAIP8L2, and A3SS of HLA-B. Furthermore, the selected four RBPs and four RASEs were validated by reverse transcription– quantitative polymerase chain reaction (RT-qPCR) and showed high consistency with RNA sequencing (RNA-seq). Conclusion: Dysregulated RBPs and their associated RASEs may play regulatory roles in MVP development and may therefore be used as therapeutic targets in the future. [ABSTRACT FROM AUTHOR]

The imbalance of CD4+Foxp3+ T cell subsets is reportedly involved in abnormal inflammatory immune responses in patients with chronic obstructive pulmonary disease (COPD). However, the possible role of CD4+CD25−Foxp3+ T cells in immune regulation in COPD remains to be investigated. In the current study, distribution and phenotypic characteristics of CD4+CD25−Foxp3+ T cells from peripheral blood were determined by flow cytometry; the origin, immune function and ultimate fate of CD4+CD25−Foxp3+ T cells were further explored in vitro. It was observed that circulating CD4+CD25−Foxp3+ T cells were significantly increased in stable COPD patients (SCOPD) and resembled central memory or effector memory T cells. Compared with peripheral CD4+CD25+Foxp3+ T cells, peripheral CD4+CD25−Foxp3+ T cells showed a lower expression of Foxp3, CTLA-4, HELIOS, and TIGIT, but a higher expression of CD127 and KI-67, suggesting that CD4+CD25−Foxp3+ T cells lost the expression of Tregs-associated molecules following the reduction in CD25. Unexpectedly, our study found that transforming growth factor-β1 (TGFβ1) decreased CD25 expression and played a critical role in the generation of CD4+CD25−Foxp3+ T cells from CD4+CD25+Foxp3+ T cells. Phenotypic analysis further revealed that both inducible and peripheral CD4+CD25−Foxp3+ T cells exhibited the features of activated conventional T cells. Importantly, memory CD4+CD25−Foxp3+ T cells facilitated the proliferation and differentiation of naïve CD4+ T cells into Th17 cells in the presence of IL-1β, IL-6, IL-23, and TGFβ1. Finally, a fraction of CD4+CD25−Foxp3+ T cells, exhibiting instability and plasticity, were converted to Th17 cells when subjected to Th17 cell-polarizing condition. Taken together, we propose that TGFβ1 is responsible for the generation of CD4+CD25−Foxp3+ T cells, and these cells functionally exert an auxiliary effect on Th17 cells generation and might perpetuate chronic inflammation in COPD. [ABSTRACT FROM AUTHOR]

The stimulator of interferon genes (STING) is a key adaptor protein mediating innate immune defense against DNA viruses. To investigate the role of STING in acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF), we isolated primary peripheral blood mononuclear cells (PBMCs) from patients and healthy controls (HCs). Raw264.7 and A549 cells were infected with herpes simplex virus type 1 (HSV-1). Mice with bleomycin- induced lung fibrosis were infected with HSV-1 to stimulate acute exacerbation of the lung fibrosis. Global gene expression profiling revealed a substantial downregulation of interferon-regulated genes (downstream of STING) in the AE-IPF group compared with the HC and stable IPF groups. The PBMCs of the AE-IPF group showed significantly reduced STING protein levels, increased levels of endoplasmic reticulum (ER) stress markers, and elevated apoptosis. HSV-1 infection decreased STING expression and stimulated the ER stress pathways in Raw264.7 and A549 cells in a time- and dose- dependent manner. HSV-1 infection exacerbated the bleomycin-induced lung injury in mice. In the primary bone marrow-derived macrophages of mice treated with bleomycin and HSV-1, STING protein expression was substantially reduced; ER stress was stimulated. Tauroursodeoxycholic acid, a known inhibitor of ER stress, partially reversed those HSV-1-mediated adverse effects in mice with bleomycin-induced lung injury. STING levels in PBMCs increased after treatment in patients showing improvement but remained at low levels in patients with deterioration. Viral infection may trigger ER stress, resulting in STING deficiency and AE-IPF onset. [ABSTRACT FROM AUTHOR]

The imbalance of CD4 + Foxp3 + T cell subsets is reportedly involved in abnormal inflammatory immune responses in patients with chronic obstructive pulmonary disease (COPD). However, the possible role of CD4 + CD25 - Foxp3 + T cells in immune regulation in COPD remains to be investigated. In the current study, distribution and phenotypic characteristics of CD4 + CD25 - Foxp3 + T cells from peripheral blood were determined by flow cytometry; the origin, immune function and ultimate fate of CD4 + CD25 - Foxp3 + T cells were further explored in vitro . It was observed that circulating CD4 + CD25 - Foxp3 + T cells were significantly increased in stable COPD patients (SCOPD) and resembled central memory or effector memory T cells. Compared with peripheral CD4 + CD25 + Foxp3 + T cells, peripheral CD4 + CD25 - Foxp3 + T cells showed a lower expression of Foxp3, CTLA-4, HELIOS, and TIGIT, but a higher expression of CD127 and KI-67, suggesting that CD4 + CD25 - Foxp3 + T cells lost the expression of Tregs-associated molecules following the reduction in CD25. Unexpectedly, our study found that transforming growth factor-β1 (TGFβ1) decreased CD25 expression and played a critical role in the generation of CD4 + CD25 - Foxp3 + T cells from CD4 + CD25 + Foxp3 + T cells. Phenotypic analysis further revealed that both inducible and peripheral CD4 + CD25 - Foxp3 + T cells exhibited the features of activated conventional T cells. Importantly, memory CD4 + CD25 - Foxp3 + T cells facilitated the proliferation and differentiation of naïve CD4 + T cells into Th17 cells in the presence of IL-1β, IL-6, IL-23, and TGFβ1. Finally, a fraction of CD4 + CD25 - Foxp3 + T cells, exhibiting instability and plasticity, were converted to Th17 cells when subjected to Th17 cell-polarizing condition. Taken together, we propose that TGFβ1 is responsible for the generation of CD4 + CD25 - Foxp3 + T cells, and these cells functionally exert an auxiliary effect on Th17 cells generation and might perpetuate chronic inflammation in COPD.