Synovial microenvironment-influenced mast cells promote the progression of rheumatoid arthritis.

Mast cells are phenotypically and functionally heterogeneous, and their state is possibly controlled by local microenvironment. Therefore, specific analyses are needed to understand whether mast cells function as powerful participants or dispensable bystanders in specific diseases. Here, we show that degranulation of mast cells in inflammatory synovial tissues of patients with rheumatoid arthritis (RA) is induced via MAS-related G protein-coupled receptor X2 (MRGPRX2), and the expression of MHC class II and costimulatory molecules on mast cells are upregulated. Collagen-induced arthritis mice treated with a combination of anti-IL-17A and cromolyn sodium, a mast cell membrane stabilizer, show significantly reduced clinical severity and decreased bone erosion. The findings of the present study suggest that synovial microenvironment-influenced mast cells contribute to disease progression and may provide a further mast cell-targeting therapy for RA.

Comparison and subsets analysis of peripheral CD4+T cells in patients with psoriasis and psoriatic arthritis.

Psoriatic arthritis (PsA) is a disease that transformed from psoriasis (PsO), and its underlying mechanisms are still not fully understood. Overactivation of the immune system is a key factor driving inflammatory diseases. Our goal is to define the unbalanced subsets of peripheral blood CD4 +T cells between PsO and PsA patients. Blood samples from 43 patients (23 PsA and 20 PsO) and 36 healthy donors (HD) were studied. Peripheral blood mononuclear cells (PBMC) were separated from blood and underwent fluorescent staining to assess CD4+T cell subsets by flow cytometry. We found that frequencies of various CD4+T cells including Th1, Th2, Th17, and Tfh were higher in the patients with PsO or PsA than those of healthy donors, indicating the general expansion of CD4+T cells in inflammatory conditions. More importantly, we observed the significant imbalance of Th1/Th2 between patients with PsO and PsA. Pearson correlation analysis showed that Th1/Th2 ratio was positively correlated with disease activity in psoriatic arthritis (DAPSA), Tfh/Tfr ratio was positively correlated with DAPSA score and visual analogue scale (VAS) score in PsA patients. Together, our results highlight the CD4+T cell changes in the transition from PsO to PsA, may contribute to early assessment and intervention.

CX-4945 inhibits fibroblast-like synoviocytes functions through the CK2-p53 axis to reduce rheumatoid arthritis disease severity.

Fibroblast-like synoviocytes (FLS) mediate many pathological processes in rheumatoid arthritis (RA), including pannus formation, bone erosion, and inflammation. RA FLS have unique aggressive phenotypes and exhibit several tumor cell-like characteristics, including hyperproliferation, excessive migration and invasion. Casein kinase 2 (CK2) is reportedly overexpressed in numerous tumor types, and targeted inhibition of CK2 has therapeutic benefits for tumors. However, the expression level of CK2 and its functions in RA FLS remain unclear. Herein, we aimed to elucidate whether CK2 is responsible for the aggressive phenotypes of RA FLS and whether targeted therapy can alleviate the severity of RA. We found that CK2 subunits were elevated in RA FLS compared with osteoarthritis FLS, and the activity of CK2 also markedly increased in RA FLS. Targeted inhibition of CK2 using CX-4945 suppressed RA FLS proliferation through cell cycle arrest. Cell migration and invasion were also inhibited by CX-4945 treatment. Moreover, CX-4945 reduced Interleukin-6 (IL-6), CC motif chemokine ligand 2 (CCL2) and Matrix metalloproteinase-3 (MMP-3) secretion in RA FLS. Further proteomic investigation revealed that p53 signaling pathway significantly changes after CX-4945 treatment in RA FLS. The siRNA-mediated p53 knockdown partly abolished the anti-proliferation and reduced IL-6, MMP-3 secretion effects of CX-4945. Furthermore, CX-4945 administration alleviates arthritis severity in CIA mice. Collectively, our results demonstrated the abnormal elevation of CK2 and its positive association with abnormal phenotypes in RA FLS. Our novel findings suggest the possible therapeutic potential of CX-4945 for RA.

γ-Tocotrienol inhibits T helper 17 cell differentiation via the IL-6/JAK/STAT3 signaling pathway.

γ-Tocotrienol (GT3), a member of the vitamin E family, is well known for its medicinal value in clinical treatments. However, the role of GT3 in T helper 17 (Th17)/regulatory T cell (Treg) differentiation and function is not fully understood. Here, we demonstrated that GT3 suppressed Th17 differentiation in vitro by inhibiting signal transducer and activator of transcription 3 (STAT3) phosphorylation in the interleukin 6 (IL-6)/Janus kinase (JAK)/STAT3 signaling pathway. GT3 also inhibited HIF1A expression in Th17 metabolism. Additionally, we showed that GT3 treatment inhibited disease aggravation in an imiquimod (IMQ)-induced psoriasis-like mouse model by reducing the percentage of Th17 cells in the spleen in vivo. The findings of this study demonstrated the effects of GT3 on Th17 cells through the STAT3 signaling pathway.

Epigallocatechin-3 gallate regulates macrophage subtypes and immunometabolism to ameliorate experimental autoimmune encephalomyelitis.

Epigallocatechin-3 gallate (EGCG) is a polyphenolic component of tea and has potential curative effects in patients with autoimmune diseases. Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS). It remains unknown whether EGCG can regulate macrophage subtypes in MS. Here we evaluated the effects of EGCG in experimental autoimmune encephalomyelitis (EAE), MS mouse model. We found that EGCG treatment reduced EAE severity and macrophage inflammation in the CNS. Moreover, EAE severity was well correlated with the ratio of M1 to M2 macrophages, and EGCG treatment suppressed M1 macrophage-mediated inflammation in spleen. In vitro experiments showed that EGCG inhibited M1 macrophage polarization, but promoted M2 macrophage polarization. These effects were likely to be related to the inhibition of nuclear factor-κB signaling and glycolysis in macrophages by EGCG in macrophages. Overall, these findings provided important insights into the mechanisms through which EGCG may mediate MS.

miRNA-467b inhibits Th17 differentiation by targeting eIF4E in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) are neuroinflammatory autoimmune diseases characterized by the axonal loss, demyelination, and neurodegeneration of the central nervous system. Overactivation of CD4+ T cells, especially the migration of the Th1 and Th17 subsets into the central nervous system (CNS), leads to the secretion of inflammatory mediators and destruction of the contact between neurons and activated macrophages, which can then result in a series of neurocognitive and motor deficits. In this study, we intended to explore the role of miRNA-467b in regulating Th cell development in EAE. We found that the level of miRNA-467b was decreased and eukaryotic initiation factor 4 F (eIF4E) was increased in lymph nodes and the CNS at EAE peak. eIF4E was confirmed as the direct target of miRNA467b. Overexpression of miRNA-467b could suppress a percentage of CD4+ IL-17+ cells in EAE CD4 + T cells in vitro. In addition, we also identified miRNA-467b, which could suppress Th17 cell differentiation by targeting eIF4E in vitro. Furthermore, injecting miRNA-467b mimics into the caudal vein of EAE mice contributed to less inflammation in the peripheral lymphoid organs and CNS and alleviated disease severity. Taken together, our findings imply that miRNA-467b inhibits the differentiation and function of Th17 cells by targeting eIF4E, thereby alleviating EAE.