Research progress of transcription activating factor 3 in regulating the alveolar macrophages in acute respiratory distress syndrome / 中华危重病急救医学

Acute respiratory distress syndrome (ARDS) refers to acute diffuse lung injury caused by a variety of intrapulmonary and/or extrapulmonary factors such as infection and trauma. Uncontrolled inflammatory response is the main pathological feature. Different functional states of alveolar macrophages have different effects on inflammatory response. Transcription activating factor 3 (ATF3) is a fast response gene in the early stage of stress. In recent years, it has been found that ATF3 plays an important role in regulating the inflammatory response of ARDS by regulating the function of macrophages. This paper reviews the regulatory effects of ATF3 on alveolar macrophage polarization, autophagy and endoplasmic reticulum stress and its effects on the inflammatory process of ARDS, aiming to provide a new research direction for the prevention and treatment of ARDS.

Molecular Dissection of Pro-Fibrotic IL11 Signaling in Cardiac and Pulmonary Fibroblasts.

In fibroblasts, TGFß1 stimulates IL11 upregulation that leads to an autocrine loop of IL11-dependent pro-fibrotic protein translation. The signaling pathways downstream of IL11, which acts via IL6ST, are contentious with both STAT3 and ERK implicated. Here we dissect IL11 signaling in fibroblasts and study IL11-dependent protein synthesis pathways in the context of approved anti-fibrotic drug mechanisms of action. We show that IL11-induced ERK activation drives fibrogenesis and while STAT3 phosphorylation (pSTAT3) is also seen, this appears unrelated to fibroblast activation. Ironically, recombinant human IL11, which has been used extensively in mouse experiments to infer STAT3 activity downstream of IL11, increases pSTAT3 in Il11ra1 null mouse fibroblasts. Unexpectedly, inhibition of STAT3 was found to induce severe proteotoxic ER stress, generalized fibroblast dysfunction and cell death. In contrast, inhibition of ERK prevented fibroblast activation in the absence of ER stress. IL11 stimulated an axis of ERK/mTOR/P70RSK protein translation and its selectivity for Collagen 1 synthesis was ascribed to an EPRS-regulated, ribosome stalling mechanism. Surprisingly, the anti-fibrotic drug nintedanib caused dose-dependent ER stress and lesser pSTAT3 expression. Pirfenidone had no effect on ER stress whereas anti-IL11 specifically inhibited the ERK/mTOR axis while reducing ER stress. These studies define the translation-specific signaling pathways downstream of IL11, intersect immune and metabolic signaling and reveal unappreciated effects of nintedanib.

Research progress on release mechanism of high mobility group protein B1 in acute respiratory distress syndrome / 中华危重病急救医学

High mobility group protein B1 (HMGB1), a highly conversed non-histone nucleoproteins with strong pro-inflammatory property, is one of the inflammatory mediator of the acute respiratory distress syndrome (ARDS). Numerous studies have confirmed that HMGB1 regulates ARDS by binding to receptor for advanced glycation end product (RAGE), Toll-like receptor (TLR) and etc. And it can significantly increase the mortality of ARDS. But the mechanism of HMGB1 release is still unclear. This study focuses on the HMGB1 release progress, which connected with Janus kinases/signal transducer and activator of transcription (JAK/STAT), nuclear factor-κB (NF-κB), Notch, inflammasome, tumor necrosis factor (TNF), mitogen-activated protein kinase (MAPK), reactive oxygen species (ROS), peroxisome proliferator-activated receptor (PPAR) and other signaling or dependent pathways in ARDS.