All-Trans Retinoic Acid Inhibits Migration and Invasiveness of Rheumatoid Fibroblast-Like Synoviocytes

Increased SNAI2 expression and defective collagen adhesion in cells with pediatric dementia, juvenile ceroid lipofuscinosis

Dementia-related neurodegenerative diseases (NDDs), including Alzheimer's disease (AD), are known to be caused by accumulation of toxic proteins. However, the molecular mechanisms that cause neurodegeneration and its biophysical effects on cells remain unclear. In this study, we used juvenile neuronal ceroid lipofuscinosis (JNCL), a pediatric dementia with a clear etiology of mutations in ceroid lipofuscinosis neuronal 3 (CLN3), to explore the changes in cell adhesion, a biophysical process that regulates neuronal development and survival. We used JNCL cerebral organoid gene expression datasets to identify the biological pathways that affect neural development, and found enriched gene expression in the epithelial-mesenchymal transition (EMT) pathway and increased expression of its inducer snail family transcriptional repressor 2 (SNAI2). A cell adhesion assay using lymphoblasts from patients with JNCL revealed defective adhesion to cell culture plates, glass surfaces, collagen type I, and neuroblast-like cells. To determine whether inhibition of EMT could improve the cell adhesion of JNCL lymphoblasts, we used all-trans retinoic acid, a well-known EMT inhibitor and inducer of neural differentiation. In JNCL lymphoblasts, ATRA treatment enhanced adhesion to collagen type I and these effects were abolished by Ca2+ chelator. These results provide new insights into the role of CLN3 and cell adhesion in the pathogenesis of NDD.

An autoantibody profile identified by human genome-wide protein arrays in rheumatoid arthritis

Precise diagnostic biomarkers of anticitrullination protein antibody (ACPA)-negative and early-stage RA are still to be improved. We aimed to screen autoantibodies in ACPA-negative patients and evaluated their diagnostic performance. The human genome-wide protein arrays (HuProt arrays) were used to define specific autoantibodies from the sera of 182 RA patients and 261 disease and healthy controls. Statistical analysis was performed with SPSS 17.0. In Phase I study, 51 out of 19,275 recombinant proteins covering the whole human genome were selected. In Phase II validation study, anti-ANAPC15 (anaphase promoting complex subunit 15) exhibited 41.8% sensitivity and 91.5% specificity among total RA patients. There were five autoantibodies increased in ACPA-negative RA, including anti-ANAPC15, anti-LSP1, anti-APBB1, anti-parathymosin, and anti-UBL7. Anti-parathymosin showed the highest prevalence of 46.2% (p = 0.016) in ACPA-negative early stage (<2 years) RA. To further improve the diagnostic efficacy, a prediction model was constructed with 44 autoantibodies. With increased threshold for RA calling, the specificity of the model is 90.8%, while the sensitivity is 66.1% (87.8% in ACPA-positive RA and 23.8% in ACPA-negative RA) in independent testing patients. Therefore, HuProt arrays identified RA-associated autoantibodies that might become possible diagnostic markers, especially in early stage ACPA-negative RA.

Identification of therapeutic targets and medicines for comorbid Crohn's disease and rheumatoid arthritis: A comprehensive analysis

Objective

The incidence of Crohn's disease (CD) and rheumatoid arthritis (RA) co-morbidity, as well as the number of individuals affected, is on the rise due to their shared molecular and cellular factors. This study aimed to identify potential therapeutic targets and medicines for comorbid CD and RA.

Methods

We integrated single-cell RNA sequencing, Mendelian randomization, and colocalization analysis results from public databases to analyse immune cell subgroups in CD and RA patients and identify candidate therapeutic targets. We further screened potential medicines for the identified candidate targets using the Comparative Toxicogenomics Database (CTD) and molecular docking and molecular dynamics simulations.

Results

The proportion of CD8 effector memory T cells (Tem) was consistently elevated in the peripheral blood mononuclear cells (PBMCs) of both CD and RA patients. MYBL1 had a causal effect on the onset of both CD (OR = 1.23; 95 % CI, 1.05-1.45; P = 0.046) and RA (OR = 1.45; 95 % CI, 1.14-1.85; P = 0.04). Four potential therapeutic molecules were retrieved from the CTD database, among which tretinoin (docking score: -6.3 kcal/mol) showed the best potential.

Conclusion

Our comprehensive analysis suggests that CD8 Tem cells are a key cell group in comorbid RA and CD and that MYBL1 has a causal effect. Tretinoin was identified as a potential targeted therapeutic drug, which is of great clinical research value.

Complement factor H attenuates TNF-α-induced inflammation by upregulating EIF3C in rheumatoid arthritis

OBJECTIVE

To explore the role and underlying mechanism of Complement Factor H (CFH) in the peripheral and joint inflammation of RA patients.

METHODS

The levels of CFH in the serum and synovial fluid were determined by ELISA. The pyroptosis of monocytes was determined by western blotting and flow cytometry. The inflammation cytokine release was tested by ELISA. The cell migration and invasion ability of fibroblast-like synoviocytes (FLS) were tested by Wound healing Assay and transwell assay, respectively. The potential target of CFH was identified by RNA sequencing.

RESULTS

CFH levels were significantly elevated in the serum and synovial fluid from RA and associated with high sensitivity C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), and disease activity score 28 (DAS28). TNF-α could inhibit CFH expression, and CFH combined with TNF-α significantly decreased cell death, cleaved-caspase 3, gasdermin E N-terminal (GSDME-N), and inflammatory cytokines release (IL-1β and IL-6) of RA-derived monocytes. Stimulated with TNF-α increased CFH levels in RA FLS and CFH inhibits the migration, invasion, and TNF-α-induced production of inflammatory mediators, including proinflammatory cytokines (IL-6, IL-8) as well as matrix metalloproteinases (MMPs, MMP1 and MMP3) of RA FLSs. The RNA-seq results showed that CFH treatment induced upregulation of eukaryotic translation initiation factor 3 (EIF3C) in both RA monocytes and FLS. The migration of RA FLSs was promoted and the expressions of IL-6, IL-8, and MMP-3 were enhanced upon EIF3C knockdown under the stimulation of CFH combined with TNF-α.

CONCLUSION

In conclusion, we have unfolded the anti-inflammatory roles of CFH in the peripheral and joints of RA, which might provide a potential therapeutic target for RA patients.

Laminar shear stress inhibits inflammation by activating autophagy in human aortic endothelial cells through HMGB1 nuclear translocation

Prevention and treatment of atherosclerosis (AS) by targeting the inflammatory response in vascular endothelial cells has attracted much attention in recent years. Laminar shear stress (LSS) has well-recognized anti-AS properties, however, the exact molecular mechanism remains unclear. In this study, we found that LSS could inhibit the increased expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), cyclooxygenase-2 (COX-2), and matrix metallopeptidase-9 (MMP-9) caused by TNF-α in an autophagy-dependent pathway in human aortic endothelial cells (HAECs) and human umbilical vein endothelial cells (HUVECs). Whole-transcriptome sequencing analysis revealed that erythropoietin-producing hepatocyte receptor B2 (EPHB2) was a key gene in response to LSS. Moreover, co-immunoprecipitation assay indicated that LSS could enhance the EPHB2-mediated nuclear translocation of high mobility group box-1 (HMGB1), which interacts with Beclin-1 (BECN1) and finally leads to autophagy. Simultaneously, we identified an LSS-sensitive long non-coding RNA (lncRNA), LOC10798635, and constructed an LSS-related LOC107986345/miR-128-3p/EPHB2 regulatory axis. Further research revealed the anti-inflammatory effect of LSS depends on autophagy activation resulting from the nuclear translocation of HMGB1 via the LOC107986345/miR-128-3p/EPHB2 axis. Our study demonstrates that LSS could regulate the expression of EPHB2 in HAECs, and the LOC107986345/miR-128-3p/EPHB2 axis plays a vital role in AS development.

Icariin arrests cell cycle progression and induces cell apoptosis through the mitochondrial pathway in human fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a highly disabling autoimmune disorder, characterized by the proliferation of Fibroblast-like Synoviocytes (FLSs). Icariin is a prenylated flavonol glycoside extracted from the medical plant Epimedium, which can inhibit the proliferation and migration of FLSs. However, the potential mechanism of icariin to alleviate RA remains unclear. In this study, icariin inhibited the migration and proliferation of FLSs in a concentration-dependent manner, by inducing G2/M phase arrest and apoptosis. Icariin reduced the mitochondrial transmembrane potential, upregulated cytosolic cytochrome c and increased the level of intracellular reactive oxygen species (ROS). In conclusion, icariin inhibited the proliferation of FLSs by interfering with the cell cycle process and inducing cell apoptosis, suggesting its potential use for the treatment of RA.

FTY720 Inhibits the Development of Collagen-Induced Arthritis in Mice by Suppressing the Recruitment of CD4+ T Lymphocytes

Background

Fingolimod (FTY720), a novel immunomodulator, was found to suppress the severity of collagen-induced arthritis (CIA) in mice. However, the potential molecular mechanisms are still unknown, and the effect of FTY720 on the recruitment of immune cells in the affected joints in the CIA model is not clear.

Materials and Methods

Following the oral administration of FTY720 (2 mg/kg) was treated into CIA mice per day for 35 days, intravital microscopy and immunofluorescence assays were performed to examine immune cell recruitment in the affected joints. Human MH7A synoviocytes were stimulated with tumour necrosis factor (TNF)-α and incubated with FTY720. Interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8) mRNA and protein expression were evaluated using RT-PCR and enzyme-linked immunosorbent assay, respectively. Signal transduction pathway protein expression was measured by Western blotting. Nuclear translocation of nuclear factor (NF)-κB was also analyzed by fluorescence microscopy.

Results

In vivo experiments showed that FTY720 inhibited the recruitment of CD4⁺ lymphocytes in the affected joints of CIA mice. FTY720 reduced the secretion of IL-1β, IL-6, and IL-8 from TNF-α-stimulated MH7A cells in a dose-dependent manner. FTY720 also inhibited TNF-α-induced phosphorylation of NF-κBp65 and IκBα, as well as NF-κBp65 nuclear translocation, in a dose- and time-dependent manner. Interestingly, FTY720 blocked PI3K/Akt, the upstream targets of the NF-κB pathway.

Conclusion

Our findings demonstrated that oral administration of FTY720 exerted beneficial effects in CIA mice by inhibiting CD4⁺ T lymphocyte recruitment to the affected joints. Our data also indicated that FTY720 inhibited TNF-α-induced inflammation by suppressing the AKT/PI3K/NF-κB pathway in MH7A cells.