Tetraspanin CD82 restrains phagocyte migration but supports macrophage activation

Distinctive function of Tetraspanins: Implication in viral infections

Harboring four transmembrane domains in their structural hallmark, Tetraspanins (Tspans) are a family of glycoproteins with pivotal functions in a variety of biological and cellular processes. Through interacting laterally with each other or specific membrane proteins, Tspans organize tetraspanin-enriched microdomains (TEMs), modulating cellular signaling, adhesion, fusion, and proliferation. An abundance of evidence has identified the multiple functions in the progression of cancer as well as the underlying molecular mechanisms. Recently, plenty of studies have focused on the utilities of Tspans by pathogens for infection, especially the infection of viruses. The expression of Tspans correlates with the phase of viral infection, the type of virus, and targeted therapies. In particular, perturbations of Tspans in host cells can affect viral attachment, intracellular trafficking, translation, virus assembly, and release. In this review, we summarize and provide a historical overview of the discovery and characterization of various kinds of virus infection and highlight their diversity and complexity, along with the virus life cycle. Furthermore, we examined the current understanding of how various Tspans are involved in the regulatory mechanisms underlying viral infection. This review aims to offer a comprehensive understanding of the targeting of Tspans for therapeutic intervention in infections caused by diverse pathogens.

The untold story of CD82: Exploring its non-canonical roles in cancer

CD82, traditionally recognized as a metastasis suppressor within the tetraspanin family, has emerged as a key player in diverse cancer-related processes beyond its canonical functions. This review highlights recent research on the non-canonical roles of CD82 in cancer progression, with a particular focus on its regulation of immune cell interactions, its impact on tumor microenvironment modulation, and its potential as both a therapeutic target and a biomarker. By examining the novel functions of CD82 in immune modulation and its influence on key signaling pathways, we propose that CD82 offers promising avenues for therapeutic interventions in cancer. This paper provides a comprehensive synthesis of the current understanding of CD82's expanded roles, underscoring its potential in improving cancer diagnosis and therapy.

Integration of Transcriptomic and Single-Cell Data to Uncover Senescence- and Ferroptosis-Associated Biomarkers in Sepsis

Background: Sepsis is a life-threatening condition characterized by organ dysfunction due to an imbalanced immune response to infection, with high mortality. Ferroptosis, an iron-dependent cell death process, and cellular senescence, which exacerbates inflammation, have recently been implicated in sepsis pathophysiology. Methods: Weighted gene co-expression network analysis (WGCNA) was used to identify ferroptosis- and senescence-related gene modules in sepsis. Differentially expressed genes (DEGs) were analyzed using public datasets (GSE57065, GSE65682, and GSE26378). Receiver operating characteristic (ROC) analysis was performed to evaluate their diagnostic potential, while single-cell RNA sequencing (scRNA-seq) was used to assess their immune-cell-specific expression. Molecular docking was conducted to predict drug interactions with key proteins. Results: Five key genes (CD82, MAPK14, NEDD4, TXN, and WIPI1) were significantly upregulated in sepsis patients and highly correlated with immune cell infiltration. MAPK14 and TXN exhibited strong diagnostic potential (AUC = 0.983, 0.978). Molecular docking suggested potential therapeutic interactions with diclofenac, flurbiprofen, and N-acetyl-L-cysteine. Conclusions: This study highlights ferroptosis and senescence as critical mechanisms in sepsis and identifies promising biomarkers for diagnosis and targeted therapy. Future studies should focus on clinical validation and precision medicine applications.

Overexpression of RBM15 modulated the effect of trophoblast cells by promoting the binding ability between YTHDF2 and the CD82 3'UTR to decrease the expression of CD82

Background

Pre-eclampsia (PE) is a syndrome with no specific pathological mechanism and is specific to pregnancy. The combined analysis of proteomics and transcriptomics possesses many benefits for treating this disease. m6A modification plays a major role in PE; however, mechanism have not been studied clearly. This study investigated the potential mechanism underlying the role of m6A in PE.

Methods

Mass spectrometry-based label-free quantitative proteomics and transcriptomics experiments were conducted on the placenta of patients with pre-eclampsia and normal pregnancies, and the two omics were followed by joint analysis. Total m6A modification in placental tissues, HTR8/SVneo cells, and JEG-3 cells was measured by dot blot. The levels of RBM15 and CD82 in tissues and cells were detected using qPCR. The protein levels of G3BP1, RBM15, MMP-2, YTHDF2, and MMP-9 were measured by western blotting. The function, migration, and invasion characteristics of HTR8/SVneo and JEG-3 cells were measured using Transwell assays. SRAMP predicted the m6A modification site in the CD82 mRNA 3'UTR, and this was confirmed using luciferase activity and YTHDF2-RIP.

Results

m6A modification was promoted in the PE group, and the RBM15 abundance was increased. Overexpression of RBM15 increased m6A modification. However, overexpression of RBM15 suppressed the expression of MMP-2 and MMP-9 and also the migratory and invasive capabilities of HTR8/SVneo and JEG-3 cells. CD82 expression levels were decreased in PE, and CD82 expression was confirmed via qPCR, western blotting and immunofluorescence. Furthermore, RBM15 overexpression reduced CD82 mRNA and protein levels. Luciferase activity and YTHDF2-RIP results verified that overexpression of RBM15 promoted the binding ability between YTHDF2 and the CD82 3'UTR, thereby decreasing CD82 expression. Finally, CD82 overexpression reversed the effect of RBM15 overexpression on the expression of MMP-2 and MMP-9 and on the migratory and invasive capabilities of the cells.

Conclusions

Overexpression of RBM15 hindered the migratory and invasive capabilities of trophoblasts, while concurrently enhancing m6A modification. The potential mechanism was that overexpression of RBM15 promoted the binding capability between YTHDF2 and CD82 3'UTR and decrease the expression of CD82. Thus, this study provides a theoretical basis for the treatment of PE.

Molecular characterization, expression pattern and immunologic function of CD82a in large yellow croaker (Larimichthys crocea)

Visceral white spot disease (VWND) caused by Pseudomonas plecoglossicida poses a major threat to the sustainable development of large yellow croaker (Larimichthys crocea) aquaculture. Genome-wide association analysis (GWAS) and RNA-seq research indicated that LcCD82a play an important role in resistance to visceral white spot disease in L. crocea, but the molecular mechanism of LcCD82a response to P. plecoglossicida infection is still unclear. In this study, we cloned and validated the Open Reading Frame (ORF) sequence of LcCD82a and explored the expression profile of LcCD82a in various tissues of L.crocea. In addition, two different transcript variants (LcCD82a-L and LcCD82a-S) of LcCD82a were identified that exhibit alternative splicing patterns after P. plecoglossicida infection, which may be closely related to the immune regulation during pathogenetic process of VWND. In order to explore the function of LcCD82a, we purified the recombinant protein of LcCD82a-L and LcCD82a-S. The bacterial agglutination and apoptosis function analysis showed that LcCD82a may involve in extracellular bacterial recognition, agglutination, and at the same time participate in the process of antigen presentation and induction of cell apoptosis. Collectively, our studies demonstrate that LcCD82a plays a crucial role in regulating apoptosis and antimicrobial immunity.

The versatile roles of testrapanins in cancer from intracellular signaling to cell-cell communication: cell membrane proteins without ligands

The tetraspanins (TSPANs) are a family of four-transmembrane proteins with 33 members in mammals. They are variably expressed on the cell surface, various intracellular organelles and vesicles in nearly all cell types. Different from the majority of cell membrane proteins, TSPANs do not have natural ligands. TSPANs typically organize laterally with other membrane proteins to form tetraspanin-enriched microdomains (TEMs) to influence cell adhesion, migration, invasion, survival and induce downstream signaling. Emerging evidence shows that TSPANs can regulate not only cancer cell growth, metastasis, stemness, drug resistance, but also biogenesis of extracellular vesicles (exosomes and migrasomes), and immunomicroenvironment. This review summarizes recent studies that have shown the versatile function of TSPANs in cancer development and progression, or the molecular mechanism of TSPANs. These findings support the potential of TSPANs as novel therapeutic targets against cancer.

Characterization and Proteomic Analysis of Plasma EVs Recovered from Healthy and Diseased Dogs with Canine Leishmaniosis

Dogs are highly valued companions and work animals that are susceptible to many life-threatening conditions such as canine leishmaniosis (CanL). Plasma-derived extracellular vesicles (EVs), exploited extensively in biomarker discovery, constitute a mostly untapped resource in veterinary sciences. Thus, the definition of proteins associated with plasma EVs recovered from healthy and diseased dogs with a relevant pathogen would be important for biomarker development. For this, we recovered, using size-exclusion chromatography (SEC), EVs from 19 healthy and 20 CanL dogs’ plasma and performed proteomic analysis by LC-MS/MS to define their core proteomic composition and search for CanL-associated alterations. EVs-specific markers were identified in all preparations and also non-EVs proteins. Some EVs markers such as CD82 were specific to the healthy animals, while others, such as the Integrin beta 3 were identified in most samples. The EVs-enriched preparations allowed the identification of 529 canine proteins that were identified in both groups, while 465 and 154 were only identified in healthy or CanL samples, respectively. A GO enrichment analysis revealed few CanL-specific terms. Leishmania spp. protein identifications were also found, although with only one unique peptide. Ultimately, CanL-associated proteins of interest were identified and a core proteome was revealed that will be available for intra- and inter-species comparisons.

Towards using 3D cellular cultures to model the activation and diverse functions of macrophages

The advent of 3D cell culture technology promises to enhance understanding of cell biology within tissue microenvironments. Whilst traditional cell culturing methods have been a reliable tool for decades, they inadequately portray the complex environments in which cells inhabit in vivo. The need for better disease models has pushed the development of effective 3D cell models, providing more accurate drug screening assays. There has been great progress in developing 3D tissue models in fields such as cancer research and regenerative medicine, driven by desires to recreate the tumour microenvironment for the discovery of new chemotherapies, or development of artificial tissues or scaffolds for transplantation. Immunology is one field that lacks optimised 3D models and the biology of tissue resident immune cells such as macrophages has yet to be fully explored. This review aims to highlight the benefits of 3D cell culturing for greater understanding of macrophage biology. We review current knowledge of macrophage interactions with their tissue microenvironment and highlight the potential of 3D macrophage models in the development of more effective treatments for disease.