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The recently identified anion channel LRRC8 volume-regulated anion channels (VRACs) are heteromeric hexamers constituted with the obligate LRRC8A subunit paired with at least one of the accessory LRRC8B to LRRC8E subunits. In addition to transport chloride, taurine, and glutamate, LRRC8 VRACs also transport the anticancer agent cisplatin and STING agonists 2'3'-cyclic GMP-AMP (cGAMP) and cyclic dinucleotides; hence, they are implicated in a variety of physiological and pathological processes, such as cell swelling, stroke, cancer, and viral infection. Although the subunit composition largely determines VRAC substrate specificity, the opening of various VRAC pores under physiological and pathological settings remains enigmatic. In this study, we demonstrated that VRACs comprising LRRC8A and LRRC8E (LRRC8A/E-containing VRACs), specialized in cGAMP transport, can be opened by a protein component present in serum under resting condition. Serum depletion ablated the tonic activity of LRRC8A/E-containing VRACs, decreasing cGAMP transport in various human and murine cells. Also, heating or proteinase K treatment abolished the ability of serum to activate VRAC. Genetic analyses revealed a crucial role for cGAMP synthase (cGAS) in serum/TNF-promoted VRAC activation. Notably, the presence of cGAS on the plasma membrane, rather than its DNA-binding or enzymatic activity, enabled VRAC activation. Moreover, phospholipid PIP2 seemed to be instrumental in the membrane localization of cGAS and its association with VRACs. Corroborating a role for LRRC8A/D-containing VRACs in cisplatin transport, serum and TNF markedly potentiated cisplatin uptake and killing of cancer cells derived from human or mouse. Together, these observations provide new insights into the complex regulation of VRAC activation and suggest a novel approach to enhance the efficacy of cGAMP and cisplatin in treating infection and cancer., (Copyright © 2021 by The American Association of Immunologists, Inc.)

Rheumatoid arthritis (RA) is a chronic inflammation that can lead to loss of range of joint abnormalities in severe cases. Diosgenin has anti-inflammatory effects. This paper discussed the effect and mechanism of diosgenin on excessive proliferation and inflammatory response of synovial cells in RA. CCK-8 detected the cell viability, TUNEL assay detected the apoptosis of cells and western blot detected the expression of apoptosis-related proteins. Wound healing was used to detect cell migration and western blot detected the expression of migration-related proteins. ELISA kits were used to detect the levels of inflammatory cytokines in cells. Diosgenin can inhibit the proliferation and migration of RA synovial cells. At the same time, diosgenin could reduce the inflammatory response of RA synovial cells, during which the expression of PDE3B was significantly decreased. By overexpressing PDE3B, we found that diosgenin inhibited the proliferation, migration, and inflammatory response of RA synovial cells by downregulating PDE3B. Diosgenin can inhibit excessive proliferation and inflammatory response of synovial fibroblasts by targeting PDE3B. [ABSTRACT FROM AUTHOR]

Hashimoto's thyroiditis (HT) is an autoimmune thyroid disorder that predominantly affects women. The role of the T-cell immunoglobulin and mucin domain-containing 4 (TIM4)/ NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) signaling pathway in macrophages has previously been studied, but its effects on macrophage-mediated HT has not yet been reported. Therefore, the aim of the current study was to explore the regulatory role of TIM4/NLRP3 in the effects of M1 macrophages on the inflammation, apoptosis and cell adhesion of thyroid follicular cells. To induce M1 macrophage, 10 ng/ml of LPS and 20 ng/ml IFN-γ were applied for the administration of THP-1 cells for 24 h. After induction, the mRNA expressions of M1 macrophage markers were assessed utilizing reverse transcription-quantitative (RT-q)PCR. Western blotting and immunofluorescence assay were adopted for the appraisement of inducible nitric oxide synthase. Additionally, the expression levels of TIM4 and NLRP3 before or after transfection were tested using RT-qPCR and western blotting. The release of inflammatory cytokines (TNF-α, IL-1β and IL-6) were estimated using RT-qPCR and western blotting was adopted for the estimation of phosphorylated (p)-p65, p65, I-κB and p-I-κB. Furthermore, the apoptosis level as well as the accompanied proteins was appraised via TUNEL and western blotting. The mRNA and protein expressions of αvβ3 were evaluated employing RT-qPCR and western blotting. The results demonstrated that TIM4 silencing decreased NLRP3 expression level in M1 macrophages. Moreover, TIM4 silencing in M1 macrophages reduced the expression levels of TNF-α, IL-6 and IL-1β, as well as the phosphorylation levels of p65 and IκB in M1 macrophages co-cultured with Nthy-ori 3-1 cells, whereas NLRP3 overexpression significantly reversed these effects. Furthermore, NLRP3 overexpression reversed the decreased apoptotic rate and cell adhesion of Nthy-ori 3-1 cells induced by TIM4 silencing. In summary, the present study demonstrated that TIM4-silencing alleviated the inflammatory damage, apoptosis and cell adhesion of M1 macrophages co-cultured with Nthy-ori 3-1 cells through downregulation of NLRP3. Therefore, the regulation of M1 macrophages via the TIM4/NLRP3 axis may be a potential therapeutic approach for the treatment of patients with HT. [ABSTRACT FROM AUTHOR]