Microtubule-dependent mechanism of anti-inflammatory effect of SOCS1 in endothelial dysfunction and lung injury

EP300 improves endothelial injury and mitochondrial dysfunction in coronary artery disease by regulating histone acetylation of SOCS1 promoter via inhibiting JAK/STAT pathway

Endothelial cell injury and mitochondrial dysfunction are crucial events during coronary artery disease (CAD). Suppressor of cytokine signaling-1 (SOCS1) is a negative mediator for inflammation, but there are few reports regarding histone acetylation of SOCS1 in CAD. The aim of the current study is to examine the impact of SOCS1 in CAD patients and human umbilical vein endothelial cells (HUVECs). We enrolled patients with CAD and healthy volunteers. HUVECs treated with ox-LDL were used as in vitro model. This study showed that SOCS1 expression was decreased in patients with CAD and ox-LDL-stimulated HUVECs. Overexpressing SOCS1 ameliorated endothelial cell injury and mitochondrial dysfunction induced by ox-LDL in vitro. Moreover, EP300 promoted SOCS1 transcription through increasing the acetylation of SOCS1 and recruiting H3K27ac to the SOCS1 gene promoter in HUVECs induced by ox-LDL. Additionally, SOCS1 repressed JAK/STAT cascade in ox-LDL-stimulated HUVECs. Silencing of EP300 reversed endothelial cell injury and mitochondrial dysfunction ameliorated by overexpression of SOCS1 in ox-LDL-induced HUVECs. In summary, SOCS1 alleviated endothelial injury and mitochondrial dysfunction via enhancing H3K27ac acetylation by recruiting EP300 to promoter region and inhibiting JAK/STAT pathway. These results contribute to discover underlying diagnostic biomarkers and therapeutic targets for CAD.

Species-specific responses during Seoul orthohantavirus infection in human and rat lung microvascular endothelial cells

Seoul orthohantavirus (SEOV) is a rat-borne zoonotic virus that is transmitted via inhalation of aerosolized infectious excreta, and can cause hemorrhagic fever with renal syndrome (HFRS) in humans worldwide. In rats, SEOV predominantly exists as a persistent infection in the absence of overt clinical signs. Lack of disease in rats is attributed to downregulation of pro-inflammatory and upregulation of regulatory host responses. As lung microvascular endothelial cells (LMECs) represent a primary target of infection in both human and rats, infections in these cells provide a unique opportunity to study the central role of LMECs in the dichotomy between pathogenicity in both species. In this study, host responses to SEOV infection in primary human and rat LMECs were directly compared on a transcriptional level. As infection of rat LMECs was more efficient than human LMECs, the majority of anti-viral defense responses were observed earlier in rat LMECs. Most prominently, SEOV-induced processes in both species included responses to cytokine stimulus, negative regulation of innate immune responses, responses to type I and II interferons, regulation of pattern recognition receptor signaling and MHC-I signaling. However, over time, in the rat LMECs, responses shifted from an anti-viral state towards a more immunotolerant state displayed by a PD-L1, B2M-, JAK2-focused interaction network aiding in negative regulation of cytotoxic CD8-positive T cell activation. This suggests a novel mechanism by which species-specific orthohantavirus-induced endothelium and T cell crosstalk may play a crucial role in the development of acute disease in humans and persistence in rodents.

Analysis and identification of ferroptosis-related genes in ulcerative colitis

BACKGROUND

Previous studies have shown that ferroptosis is associated with the pathogenesis of ulcerative colitis (UC). Therefore, this study aimed to identify key ferroptosis-related genes (FRGs) associated with the diagnosis of UC.

METHODS

UC-related expression datasets were downloaded from the Gene Expression Omnibus (GEO) database. First, Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify UC-related genes (UCRGs). Differentially expressed genes (DEGs) between normal and UC groups were screened in GSE87466, and DEGs were subjected to an intersection analysis with FRGs and UCRGs to obtain ferroptosis-related DEGs (FR DEGs). Then a protein-protein interaction (PPI) network was constructed for FR DEGs. The hub genes were extracted based on the degree, Maximum Neighborhood Component (MNC), closeness, and Maximal Clique Centrality (MCC). Biomarkers with diagnostic values were screened by support vector machine (SVM) and the least absolute shrinkage and selection operator (LASSO) algorithms. Next, the infiltration of immune cells was compared between UC and normal groups, and the correlation between different immune cells and diagnostic genes was analyzed. The biological functions, classical pathways, and intermolecular interaction networks of diagnostic genes were characterized utilizing ingenuity pathway analysis (IPA). Finally, a TF-mRNA network was constructed and potential small-molecule compounds were screened.

RESULTS

Thirty-six FR DEGs were obtained, and these were enriched in biological processes such as positive regulation of cytokine production, cytokine-mediated signalling pathway, long-chain fatty acid-CoA ligase activity, etc. Among 18 hub genes, five genes (ALOX5, TIMP1, TNFAIP3, SOCS1, DUOX2) were captured with diagnostic values for UC, and they displayed significant differences between UC and normal groups. Sixteen immune cell infiltrates were significantly different between UC and normal groups, such as activated dendritic cells and resting dendritic cells. TNFAIP3 and ALOX5 were positively correlated with neutrophils, and TIMP1, SOCS1, ALOX5, and DUOX2 were negatively correlated with M2 macrophages. IPA showed that diagnostic genes were related to 43 function modules and activated 17 pathways. The constructed TF-mRNA regulatory network comprised three diagnostic genes and 17 differentially expressed TFs. Potential small-molecule compounds including helveticoside and cymarin were identified.

CONCLUSION

Our findings yielded several promising FRGs for UC, providing a scientific reference for further studies on the pathogenesis of UC.

Recent progress and prospects for anti-cytokine therapy in preclinical and clinical acute lung injury

Acute respiratory distress syndrome (ARDS) is a heterogeneous cause of respiratory failure that has a rapid onset, a high mortality rate, and for which there is no effective pharmacological treatment. Current evidence supports a critical role of excessive inflammation in ARDS, resulting in several cytokines, cytokine receptors, and proteins within their downstream signalling pathways being putative therapeutic targets. However, unsuccessful trials of anti-inflammatory drugs have thus far hindered progress in the field. In recent years, the prospects of precision medicine and therapeutic targeting of cytokines coevolving into effective treatments have gained notoriety. There is an optimistic and growing understanding of ARDS subphenotypes as well as advances in treatment strategies and clinical trial design. Furthermore, large trials of anti-cytokine drugs in patients with COVID-19 have provided an unprecedented amount of information that could pave the way for therapeutic breakthroughs. While current clinical and nonclinical ARDS research suggest relatively limited potential in monotherapy with anti-cytokine drugs, combination therapy has emerged as an appealing strategy and may provide new perspectives on finding safe and effective treatments. Accurate evaluation of these drugs, however, also relies on well-founded experimental research and the implementation of biomarker-guided stratification in future trials. In this review, we provide an overview of anti-cytokine therapy for acute lung injury and ARDS, highlighting the current preclinical and clinical evidence for targeting the main cytokines individually and the therapeutic prospects for combination therapy.

Microtubules as Major Regulators of Endothelial Function: Implication for Lung Injury

Endothelial dysfunction has been attributed as one of the major complications in COVID-19 patients, a global pandemic that has already caused over 4 million deaths worldwide. The dysfunction of endothelial barrier is characterized by an increase in endothelial permeability and inflammatory responses, and has even broader implications in the pathogenesis of acute respiratory syndromes such as ARDS, sepsis and chronic illnesses represented by pulmonary arterial hypertension and interstitial lung disease. The structural integrity of endothelial barrier is maintained by cytoskeleton elements, cell-substrate focal adhesion and adhesive cell junctions. Agonist-mediated changes in endothelial permeability are directly associated with reorganization of actomyosin cytoskeleton leading to cell contraction and opening of intercellular gaps or enhancement of cortical actin cytoskeleton associated with strengthening of endothelial barrier. The role of actin cytoskeleton remodeling in endothelial barrier regulation has taken the central stage, but the impact of microtubules in this process remains less explored and under-appreciated. This review will summarize the current knowledge on the crosstalk between microtubules dynamics and actin cytoskeleton remodeling, describe the signaling mechanisms mediating this crosstalk, discuss epigenetic regulation of microtubules stability and its nexus with endothelial barrier maintenance, and overview a role of microtubules in targeted delivery of signaling molecules regulating endothelial permeability and inflammation.