Single-cell transcriptomic analysis to identify endomembrane regulation of metalloproteins and motor proteins in autoimmunity.

TMEM230 promotes antigen processing, trafficking, and presentation by regulating the endomembrane system of membrane bound organelles (lysosomes, proteosomes and mitochondria) and phagosomes. Activation of the immune system requires trafficking of various cargos between the endomembrane system and cell plasma membrane. The Golgi apparatus is the hub of the endomembrane system and essential for the generation, maintenance, recycling, and trafficking of the components of the endomembrane system itself and immune system. Intracellular trafficking and secretion of immune system components depend on mitochondrial metalloproteins for ATP synthesis that powers motor protein transport of endomembrane cargo. Glycan modifying enzyme genes and motor proteins are essential for the activation of the immune system and trafficking of antigens between the endomembrane system and the plasma membrane. Recently, TMEM230 was identified as co-regulated with RNASET2 in lysosomes and with metalloproteins in various cell types and organelles, including mitochondria in autoimmune diseases. Aberrant metalloproteinase secretion by motor proteins is a major contributor to tissue remodeling of synovial membrane and joint tissue destruction in rheumatoid arthritis (RA) by promoting infiltration of blood vessels, bone erosion, and loss of cartilage by phagocytes. In this study, we identified that specific glycan processing enzymes are upregulated in certain cell types (fibroblast or endothelial cells) that function in destructive tissue remodeling in rheumatoid arthritis compared to osteoarthritis (OA). TMEM230 was identified as a regulator in the secretion of metaloproteinases and heparanase necessary tissue remodeling in OA and RA. In dendritic (DC), natural killer and T cells, TMEM230 was expressed at low or no levels in RA compared to OA. TMEM230 expression in DC likely is necessary for regulatory or helper T cells to maintain tolerance to self-antigens and prevent susceptibility to autoimmune disease. To identify how TMEM230 and the endomembrane system contribute to autoimmunity we investigated, glycan modifying enzymes, metalloproteinases and motor protein genes co-regulated with or regulated by TMEM230 in synovial tissue by analyzing published single cell transcriptomic datasets from RA patient derived synovial tissue.

Analysis of survival rate and persistence predictors of baricitinib in real-world data from a large cohort of rheumatoid arthritis patients.

Objectives: The persistence in therapy of rheumatoid arthritis drugs and particularly bDMARD is a limiting factor for their long-term use. The randomized controlled trials (RCTs) may not reflect real-world contexts due to strict inclusion and exclusion criteria. Baricitinib, which targets both JAK1 and JAK2, has been used in Italy for several years. The aim of this multi-center study is to assess the real world persistence on therapy of baricitinib in RA patients and to identify predictive factors of baricitinib's survival rate. Methods: This is a retrospective, multicentric, Italian, longitudinal study. All patients were enrolled according to the following criteria: a) age ≥ 18 years old; b) diagnosed with RA according 2010 ACR/EULAR classification criteria; c) treated with baricitinib. In order to describe baricitinib clinical efficacy, the survival rate was evaluated by The Kaplan-Meier curve. Then, predictive factors of drug retention rate were assessed by performing the Cox analysis, identifying which risk factors influenced treatment persistence. Results: Overall, we included 478 patients treated with baricitinib. Among them, 380 (79.5%) were females. Baricitinib's survival rate was 94.6% at 6 months, 87.9% at 12 months, 81.7% at 24 months and 53.4% at 48 months. The Cox analysis regression showed that a higher bDMARDs/tsDMARD line of therapy seems to be a negative prognostic factor for the drug retention rate (HR 1.26 CI 95% 1.07-1.49, p = 0.006. Conclusion: Real-life study confirms baricitinib effectiveness up to 4 years, but previous treatment with bDMARDs was a negative prognostic factor for its survival rate.