Tim‑3 regulates the ability of macrophages to counter lipopolysaccharide‑induced pulmonary epithelial barrier dysfunction via the PI3K/Akt pathway in epithelial cells

Tim-3 Is Not Required for Establishment of CD8+ T Cell Memory to Lymphocytic Choriomeningitis Virus

Tim-3 is a transmembrane protein that is best known for being highly expressed on terminally exhausted CD8+ T cells associated with chronic infection and tumors, although its expression is not limited to those settings. Tim-3 is also expressed by CD8+ T cells during acute infection and by multiple other immune cell types, including CD4+ Th1 and regulatory T cells, dendritic cells, and mast cells. In this study, we investigated the role of Tim-3 signaling on CD8+ T cell memory using a Tim-3 conditional knockout mouse model and mice lacking the signaling portion of the Tim-3 cytoplasmic domain. Together, our results indicate that Tim-3 has at most a modest effect on the formation and function of CD8+ memory T cells.

Inhibition of EZH2 Ameliorates Sepsis Acute Lung Injury (SALI) and Non-Small-Cell Lung Cancer (NSCLC) Proliferation through the PD-L1 Pathway

(1) Background: Both sepsis acute lung injury (SALI) and non-small-cell lung cancer (NSCLC) are life-threatening diseases caused by immune response disorders and inflammation, but the underlining linking mechanisms are still not clear. This study aimed to detect the shared gene signature and potential molecular process between SALI and NSCLC. (2) Methods: RNA sequences and patient information on sepsis and NSCLC were acquired from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was used to build a co-expression network associated with sepsis and NSCLC. Protein-protein interaction (PPI) analysis of shared genes was intuitively performed by the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database. The involvement of EZH2 in the tumor immune microenvironment (TIME) and sepsis immune microenvironment (IME) was assessed by R software. Western blot, flow cytometry, and other in vitro assays were performed to further confirm the function and mechanism of EZH2 in NSCLC and SALI. (3) Results: WGCNA recognized three major modules for sepsis and two major modules for NSCLC, and there were seven shared genes identified for the two diseases. Additionally, the hub gene EZH2 was screened out. It was shown that EZH2 was closely related to the IME in the two diseases. In the validation assay, our data showed that EZH2 was expressed at a higher level in peripheral blood mononuclear cells (PBMCs) of septic patients than those of healthy donors (HDs), and EZH2 was also expressed at a higher level in lipopolysaccharide (LPS)-induced PBMCs and non-small cell lung cancer (A549) cells. EZH2 inhibitor (GSK343) downregulated the proliferation ability of A549 cells in a concentration-dependent manner, parallel with the decreased expression level of PD-L1. Similarly, GSK343 inhibited PD-L1 protein expression and downregulated the level of proinflammatory factors in LPS-induced PBMCs. In the co-culture system of PBMCs and human type II alveolar epithelial cells (ATIIs), the addition of GSK343 to PBMCs significantly downregulated the apoptosis of LPS-induced ATIIs. (4) Conclusions: This study illustrated that EZH2 inhibition could ameliorate A549 cell proliferation and LPS-induced ATII apoptosis in parallel with downregulation of PD-L1 protein expression, which provided new insights into molecular signaling networks involved in the pathogenetics of SALI and NSCLC.

The role of lung macrophages in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is an acute and diffuse inflammatory lung injury in a short time, one of the common severe manifestations of the respiratory system that endangers human life and health. As an innate immune cell, macrophages play a key role in the inflammatory response. For a long time, the role of pulmonary macrophages in ARDS has tended to revolve around the polarization of M1/M2. However, with the development of single-cell RNA sequencing, fate mapping, metabolomics, and other new technologies, a deeper understanding of the development process, classification, and function of macrophages in the lung are acquired. Here, we discuss the function of pulmonary macrophages in ARDS from the two dimensions of anatomical location and cell origin and describe the effects of cell metabolism and intercellular interaction on the function of macrophages. Besides, we explore the treatments for targeting macrophages, such as enhancing macrophage phagocytosis, regulating macrophage recruitment, and macrophage death. Considering the differences in responsiveness of different research groups to these treatments and the tremendous dynamic changes in the gene expression of monocyte/macrophage, we discussed the possibility of characterizing the gene expression of monocyte/macrophage as the biomarkers. We hope that this review will provide new insight into pulmonary macrophage function and therapeutic targets of ARDS.

Transcription of the Envelope Protein by 1-L Protein–RNA Recognition Code Leads to Genes/Proteins That Are Relevant to the SARS-CoV-2 Life Cycle and Pathogenesis

The theoretical protein–RNA recognition code was used in this study to research the compatibility of the SARS-CoV-2 envelope protein (E) with mRNAs in the human transcriptome. According to a review of the literature, the spectrum of identified genes showed that the virus post-transcriptionally promotes or represses the genes involved in the SARS-CoV-2 life cycle. The identified genes/proteins are also involved in adaptive immunity, in the function of the cilia and wound healing (EMT and MET) in the pulmonary epithelial tissue, in Alzheimer’s and Parkinson’s disease and in type 2 diabetes. For example, the E-protein promotes BHLHE40, which switches off the IL-10 inflammatory “brake” and inhibits antiviral T_Hαβ cells. In the viral cycle, E supports the COPII-SCAP-SREBP-HSP90α transport complex by the lowering of cholesterol in the ER and by the repression of insulin signaling, which explains the positive effect of HSP90 inhibitors in COVID-19 (geldanamycin), and E also supports importin α/β-mediated transport to the nucleus, which explains the positive effect of ivermectin, a blocker of importins α/β. In summary, transcription of the envelope protein by the 1-L protein–RNA recognition code leads to genes/proteins that are relevant to the SARS-CoV-2 life cycle and pathogenesis.

Chitosan Nanoparticles Loaded with TGF-β1 Inhibit Cervical Cancer Cell Progression Through Down-Regulation of MicroRNA-155 and Activation of Tim-3 Pathway

Chemically modified chitosan nanoparticles (NPs) are capable of releasing their own substances to target cells or tissues, improving microenvironment and promoting wound healing. This study aimed to explore the molecular mechanism underlying chitosan NPs loaded with TGF-β1 participating in cervical cancer (CC) progression. TGF-β1-loaded-chitosan NPs were prepared and particle size distribution, zeta potential and encapsulation efficiency of NPs were determined. MTT assay assessed the toxicity of NPs to macrophages. CC cells were co-cultured with TGF-β1-loaded chitosan NPs (experimental group) or pure chitosan NPs (control group) and cells were cultured alone to produce control group. After treatment, flow cytometry was conducted to detect apoptosis and cycle. Cancer cell migration was evaluated by Transwell assay, and miR-155 and Tim-3 expression was determined. At a ratio of 2:1 chitosan and TGF-β1, the particle size was102.65±11.98 nm, which was smallest, with high encapsulation rate of 81.26%, and low potential of 1.46±1.71. NP toxicity increased as concentration rose and relative cell proliferation rate was >80%, indicated as non-toxic. CC tissues had positive expression of CD163 and TGF-β1 (95%) (p < 0.05). Treatment with TGF-β1-loaded chitosan NPs induced increased apoptosis rate of 9.13±2.15%, reduced migration (67.65±9.91) and invaded cells (19.98±3.41), causing cell accumulation in the S phase when compared to the blank and control groups (p < 0.05). Besides, experimental group exhibited lower expression of miR-155 (0.39±0.59) and higher expression of Tim-3 (2.87± 0.51), which was higher than the blank group and control group. The optimal concentration ratio for producing TGF-β1-loaded chitosan NPs was 2:1, with less toxicity. The composite NPs suppressed malignant characteristics of CC cells through down-regulation of miR-155 and activation of Tim-3 signal pathway on the surface of macrophages, promoting secretion of macrophage inflammatory factors.