Dysregulated thrombospondin 1 and miRNA-29a-3p in severe COVID-19.

Although nearly a fifth of symptomatic COVID-19 patients suffers from severe pulmonary inflammation, the mechanism of developing severe illness is not yet fully understood. To identify significantly altered genes in severe COVID-19, we generated messenger RNA and micro-RNA profiling data of peripheral blood mononuclear cells (PBMCs) from five COVID-19 patients (2 severe and 3 mild patients) and three healthy controls (HC). For further evaluation, two publicly available RNA-Seq datasets (GSE157103 and GSE152418) and one single-cell RNA-Seq dataset (GSE174072) were employed. Based on RNA-Seq datasets, thrombospondin 1 (THBS1) and interleukin-17 receptor A (IL17RA) were significantly upregulated in severe COVID-19 patients' blood. From single-cell RNA-sequencing data, IL17RA level is increased in monocytes and neutrophils, whereas THBS1 level is mainly increased in the platelets. Moreover, we identified three differentially expressed microRNAs in severe COVID-19 using micro-RNA sequencings. Intriguingly, hsa-miR-29a-3p significantly downregulated in severe COVID-19 was predicted to bind the 3'-untranslated regions of both IL17RA and THBS1 mRNAs. Further validation analysis of our cohort (8 HC, 7 severe and 8 mild patients) showed that THBS1, but not IL17RA, was significantly upregulated, whereas hsa-miR-29a-3p was downregulated, in PBMCs from severe patients. These findings strongly suggest that dysregulated expression of THBS1, IL17RA, and hsa-miR-29a-3p involves severe COVID-19.

ESRRA (estrogen related receptor alpha) is a critical regulator of intestinal homeostasis through activation of autophagic flux via gut microbiota.

The orphan nuclear receptor ESRRA (estrogen related receptor alpha) is critical in mitochondrial biogenesis and macroautophagy/autophagy function; however, the roles of ESRRA in intestinal function remain uncharacterized. Herein we identified that ESRRA acts as a key regulator of intestinal homeostasis by amelioration of colonic inflammation through activation of autophagic flux and control of host gut microbiota. Esrra-deficient mice presented with increased susceptibility to dextran sodium sulfate (DSS)-induced colitis with upregulation of intestinal inflammation. In addition, esrra-null mice had depressed AMP-activated protein kinase phosphorylation (AMPK), lower levels of TFEB (transcription factor EB), and accumulation of SQSTM1/p62 (sequestosome 1) with defective mitochondria in intestinal tissues. Esrra-deficient mice showed distinct gut microbiota composition and significantly higher microbial diversity than wild-type (WT) mice. Cohousing or fecal microbiota transplantation from WT mice to Esrra-deficient mice ameliorated DSS-induced colitis severity. Importantly, patients with ulcerative colitis (UC) had significantly decreased ESRRA expression in intestinal mucosal tissues that correlated with disease activity, suggesting clinical relevance of ESRRA in UC. Taken together, our results show that ESRRA contributes to intestinal homeostasis through autophagy activation and gut microbiota control to protect the host from detrimental inflammation and dysfunctional mitochondria.Abbreviations: ABX, antibotics; AMPK, AMP-activated protein kinase; ATP5A1, ATP synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1; BECN1, beclin1, autophagy related, CCL, C-C motif chemokine ligand; CD, Crohn disease; CLDN, claudin; COX4I1, cytochrome c oxidase subunit 4I1; cKO, conditional knockout; cWT, conditional wild-type; CXCL, C-X-C motif chemokine ligand; DAI, disease activity index; DSS, dextran sodium sulfate; EGFP, enhanced green fluorescent protein; ESRR, estrogen related receptor; ESRRA, estrogen related receptor alpha; Esrra+/+, Esrra wild type; esrra-/-, esrra homozygous knockout; FMT, fecal microbiota transplantation; GABARAP, gamma-aminobutyric acid receptor associated protein; GSEA, gene set enrichment analysis; IBD, inflammatory bowel disease; IL, interleukin; KO, knockout; LAMP1, lysosomal-associated membrane protein 1; LCN2, lipocalin 2; LEfSe, linear discriminant analysis (LDA) effect size; LPS, lipopolysachharide; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; NDUFAB1, NADH: ubiquinone oxidoreductase subunit AB1; OCLN, occludin; OUT, operational taxonomic unit; OXPHOS, oxidative phosphorylation; PCoA, principal coordinate analysis; PPARGC1A, PPARG coactiva- tor 1 alpha; PRKAA, 5'-AMP-activated protein kinase catalytic subunit alpha; PTGS2/COX2, prostaglandin-endoperoxide synthase 2; RAB7, member RAS oncogene family; SDHB, succinate dehydrogenase complex, subunit B, iron sulfur (Ip); SQSTM1/p62, sequestosome 1; S100A9, S100 calcium binding protein A9 (calgranulin B); TCA, tricarboxylic acid; TFEB, transcription factor EB; TNF, tumor necrosis factor; UC, ulcerative colitis; UCP2, uncoupling protein 2 (mitochondrial, proton carrier); UQCRC1, ubiquinol-cytochrome c reductase core protein 1; UVRAG, UV radiation resistance associated gene; Vil1, villin; VPS11, VPS11, CORVET/HOPS core sub-unit; WT, wild type.

Long pentraxin PTX3 mediates acute inflammatory responses against pneumococcal infection.

Streptococcus pneumoniae is an important human pathogen responsible for more than 2 million deaths annually worldwide. The airway epithelium acts as the first-line of defense against pneumococcal infections by regulating acute inflammation against invading pneumococcus. Despite the intact adaptive immunity, failure in early defense due to loss of pattern recognition receptors (PRRs) and/or acute phase proteins (APPs) results in detrimental damage and death. C-reactive protein (CRP), the first found APP, is a member of the pentraxin family of proteins and an important soluble PRR for pneumococcus. CRP and another short pentraxin, serum amyloid P, are critical for acute defense against pneumococcal infection. However, the role of the long pentraxin PTX3 in regulating pneumococcal infections is unknown. In this study, PTX3 expression was upregulated by pneumococcus in epithelial cells and in lungs of mice. In addition, PTX3 potentiated pneumococcal inflammation; overexpression of PTX3 enhanced pneumococcus-induced cytokine expression, whereas knock-down of PTX3 with siPTX3 inhibited the cytokine expression. Furthermore, PTX3 deficiency indeed ameliorated acute inflammation and protected mice against death following pneumococcal infection. Pneumococcal toxin pneumolysin was responsible for PTX3 expression and upregulated PTX3 expression via JNK MAPK signaling. These data implicate PTX3 as a novel therapeutic target for the control of acute inflammation by pneumococcus.

PAI-1 inhibits development of chronic otitis media and tympanosclerosis in a mouse model of otitis media.

CONCLUSION: Bullae of type 1 plasminogen activator inhibitor (PAI-1) knockout (KO) mice showed low levels of inflammation against nontypable Haemophilus influenzae (NTHi) at the early stage of otitis media (OM). However, PAI-1 KO mice fail to terminate inflammation, which may significantly contribute to the development of tympanosclerosis in PAI-1 KO mice. OBJECTIVE: To investigate the role of PAI-1 in the pathogenesis of OM and subsequent tympanosclerosis. METHODS: OM was induced with NTHi in PAI-1 KO and background control C57BL/6 mice. mRNA expression of PAI-1, tissue-type plasminogen activator (tPA), and urokinase-type plasminogen activator (uPA) was measured in the bullae of C57BL/6 mice. mRNA expression of interleukin (IL)-1ß, tumor necrosis factor (TNF) α, macrophage inflammatory protein (MIP-2), tPA, and uPA in PAI-1 KO and C57BL/6 mice was compared. Histological changes produced by OM were compared at 1, 3, and 7 days after NTHi inoculation. RESULTS: NTHi up-regulated the expression of PAI-1 and tPA in the bullae of C57BL/6 mice, but not uPA. mRNA expression of IL-1ß, TNFα, and MIP-2 was low in PAI-1 KO mice at early time points, but significantly higher at the later stage of OM. Similarly to the gene expression results, histological changes associated with OM were less at days 1 and 3 in PAI-1 KO mice. However, unlike the gradual resolution of OM pathologies in C57BL/6 mice, PAI-1 KO mice showed significant pathological changes of tympanosclerosis.