The matricellular protein thrombospondin-1 in lung inflammation and injury

Improvement of Inflammation and Abnormal Vascularization by TSP1 Treatment Combined with ADSCs Transplantation in Mice with Induced Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common gynecological endocrine disease with a certain degree of chronic inflammation and abnormal ovarian angiogenesis in reproductive women. Mesenchymal stem cells (MSCs) have potent immunomodulatory properties to regulate ovarian function, while thrombospondin 1 (TSP1) improves the abnormal formation of ovarian vessels. The present study investigated the efficacy of the combined use of adipose-derived mesenchymal stem cells (ADSCs) and TSP1 in PCOS mice. The PCOS model is established using dehydroepiandrosterone (DHEA) by subcutaneous injection. Ovarian apoptosis is assessed using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Real-time quantitative PCR (RT-PCR) and western blotting are used to detect the expression of inflammatory factors and the levels of angiogenesis-related factors in ovarian tissues. Inflammatory cells count and ovarian angiogenesis are evaluated by immunofluorescence staining. This research shows that TSP1 and ADSCs treatment can significantly reduce the inflammatory state of PCOS mice, relieve the degree of ovarian cell apoptosis, optimize the ovarian histological manifestations, and restore the levels of related hormones. The proportion of CD31-positive cells in PCOS mice returned to near-normal levels. The synergistic use of ADSCs and TSP1 therapy can exert a more impressive effect by inhibiting the ovarian inflammatory response and regulating the balance of angiogenesis than the single application in PCOS mice.

Investigation of a UPR-Related Gene Signature Identifies the Pro-Fibrotic Effects of Thrombospondin-1 by Activating CD47/ROS/Endoplasmic Reticulum Stress Pathway in Lung Fibroblasts

Unfolded protein response (UPR) signaling and endoplasmic reticulum (ER) stress have been linked to pulmonary fibrosis. However, the relationship between UPR status and pulmonary function and prognosis in idiopathic pulmonary fibrosis (IPF) patients remains largely unknown. Through a series of bioinformatics analyses, we established a correlation between UPR status and pulmonary function in IPF patients. Furthermore, thrombospondin-1 (TSP-1) was identified as a potential biomarker for prognostic evaluation in IPF patients. By utilizing both bulk RNA profiling and single-cell RNA sequencing data, we demonstrated the upregulation of TSP-1 in lung fibroblasts during pulmonary fibrosis. Gene set enrichment analysis (GSEA) results indicated a positive association between TSP-1 expression and gene sets related to the reactive oxygen species (ROS) pathway in lung fibroblasts. TSP-1 overexpression alone induced mild ER stress and pulmonary fibrosis, and it even exacerbated bleomycin-induced ER stress and pulmonary fibrosis. Mechanistically, TSP-1 promoted ER stress and fibroblast activation through CD47-dependent ROS production. Treatment with either TSP-1 inhibitor or CD47 inhibitor significantly attenuated BLM-induced ER stress and pulmonary fibrosis. Collectively, these findings suggest that the elevation of TSP-1 during pulmonary fibrosis is not merely a biomarker but likely plays a pathogenic role in the fibrotic changes in the lung.

Complex Neuroimmune Involvement in Neurodevelopment: A Mini-Review

It is increasingly evident that cells and molecules of the immune system play significant roles in neurodevelopment. As perinatal infection is associated with the development of neurodevelopmental disorders, previous research has focused on demonstrating that the induction of neuroinflammation in the developing brain is capable of causing neuropathology and behavioral changes. Recent studies, however, have revealed that immune cells and molecules in the brain can influence neurodevelopment without the induction of overt inflammation, identifying neuroimmune activities as integral parts of normal neurodevelopment. This mini-review describes the shift in literature that has moved from emphasizing the intrusion of inflammatory events as a main culprit of neurodevelopmental disorders to evaluating the deviation of the normal neuroimmune activities in neurodevelopment as a potential pathogenic mechanism.

Proteoglycans: a common portal for SARS-CoV-2 and extracellular vesicle uptake

As structural components of the glycocalyx, heparan sulfate proteoglycans (HSPGs) are involved in multiple pathophysiological processes at the apex of cell signaling cascades, and as endocytosis receptors for particle structures, such as lipoproteins, extracellular vesicles, and enveloped viruses, including SARS-CoV-2. Given their diversity and complex biogenesis regulation, HSPGs remain understudied. Here we compile some of the latest studies focusing on HSPGs as internalizing receptors of extracellular vesicles ("endogenous virus") and SARS-CoV-2 lipid-enclosed particles and highlight similarities in their biophysical and structural characteristics. Specifically, the similarities in their biogenesis, size, and lipid composition may explain a common dependence on HSPGs for efficient cell-surface attachment and uptake. We further discuss the relative complexity of extracellular vesicle composition and the viral mechanisms that evolve towards increased infectivity that complicate therapeutic strategies addressing blockade of their uptake.

The carboxyl-terminal TSP1-homology domain is the biologically active effector peptide of matricellular protein CCN5 that counteracts profibrotic CCN2

Cellular Communication Network (CCN) proteins have multimodular structures important for their roles in cellular responses associated with organ development and tissue homeostasis. CCN2 has previously been reported to be secreted as a preproprotein that requires proteolytic activation to release its bioactive carboxyl-terminal fragment. Here, our goal was to resolve whether CCN5, a divergent member of the CCN family with converse functions relative to CCN2, releases the TSP1 homology domain as its bioactive signaling entity. The recombinant CCN5 or CCN3 TSP1 homology domains were produced in ExpiCHO-S or DG44 CHO cells as secretory fusion proteins appended to the carboxyl-terminal end of His-Halo-Sumo or amino-terminal end of human albumin and purified from the cell culture medium. We tested these fusion proteins in various phosphokinase signaling pathways or cell physiologic assays. Fusion proteins with the CCN5 TSP1 domain inhibited key signaling pathways previously reported to be stimulated by CCN2, irrespective of fusion partner. The fusion proteins also efficiently inhibited CCN1/2-stimulated cell migration and gap closure following scratch wound of fibroblasts. Fusion protein with the CCN3 TSP1 domain inhibited these functions with similar efficacy and potency as that of the CCN5 TSP1 domain. The CCN5 TSP1 domain also recapitulated a positive regulatory function previously assigned to full-length CCN5, that is, induction of estrogen receptor-α mRNA expression in triple negative MDA-MB-231 mammary adenocarcinoma cells and inhibited epithelial-to-mesenchymal transition and CCN2-induced mammosphere formation of MCF-7 adenocarcinoma cells. In conclusion, the CCN5 TSP1 domain is the bioactive entity that confers the biologic functions of unprocessed CCN5.