Regenerating gene (REG) 1 alpha promotes pannus progression in patients with rheumatoid arthritis

Matrine Alleviates Atherosclerosis by Targeting REG1A and Activating the PI3K/AKT/mTOR Pathway to Inhibit Endothelial Cell Ferroptosis

Matrine, a natural alkaloid, has a wide range of pharmacological effects, such as antibacterial, anti-inflammatory, anti-oxidation, and anti-tumor. However, the molecular mechanism of matrine in the treatment of atherosclerosis (AS) is not fully understood. Human umbilical vein endothelial cells (HUVECs) were treated with 100 μg/mL ox-LDL to construct an AS cell model in vitro, and the cells were treated with matrine at different concentrations. Our results showed that matrine alleviated the decrease of HUVEC viability and the increase of ferroptosis induced by ox-LDL treatment. Subsequently, we found that matrine targeted regenerating family member 1 alpha (REG1A) and inhibited the expression level of REG1A in ox-LDL treated HUVECs. Overexpression of REG1A attenuated the improvement of matrine on activation of the PI3K/Akt/mTOR pathway and ferroptosis in ox-LDL treated HUVECs. In addition, both LY294002 (an inhibitor of the PI3K signaling) and Erastin (an inducer of ferroptosis) reversed the alleviation of matrine treatment on ferroptosis in ox-LDL treated HUVECs. The results in vivo showed that matrine treatment inhibited high-fat diet-induced aortic ferroptosis in ApoE-/- mice and alleviated arterial tissue lesions. In summary, matrine inhibits ferroptosis by targeting REG1A to activate PI3K/Akt/mTOR pathway, thereby alleviating aortic endothelial injury and lipid plaque formation in AS mice, suggesting that matrine has potential value for the treatment of AS.

The Potential Role of REG Family Proteins in Inflammatory and Inflammation-Associated Diseases of the Gastrointestinal Tract

Regenerating gene (REG) family proteins serve as multifunctional secretory molecules with trophic, antiapoptotic, anti-inflammatory, antimicrobial and probably immuno-regulatory effects. Since their discovery, accumulating evidence has clarified the potential roles of the REG family in the occurrence, progression and development of a wide range of inflammatory and inflammation-associated diseases of the gastrointestinal (GI) tract. However, significant gaps still exist due to the undefined nature of certain receptors, regulatory signaling pathways and possible interactions among distinct Reg members. In this narrative review, we first describe the structural features, distribution pattern and purported regulatory mechanisms of REG family proteins. Furthermore, we summarize the established and proposed roles of REG proteins in the pathogenesis of various inflammation-associated pathologies of the GI tract and the body as a whole, focusing particularly on carcinogenesis in the ulcerative colitis—colitic cancer sequence and gastric cancer. Finally, the clinical relevance of REG products in the context of diagnosis, treatment and prognostication are also discussed in detail. The current evidence suggests a need to better understanding the versatile roles of Reg family proteins in the pathogenesis of inflammatory-associated diseases, and their broadened future usage as therapeutic targets and prognostic biomarkers is anticipated.

Expression of REG family genes in human inflammatory bowel diseases and its regulation

The pathophysiology of inflammatory bowel disease (IBD) reflects a balance between mucosal injury and reparative mechanisms. Some regenerating gene (Reg) family members have been reported to be expressed in Crohn's disease (CD) and ulcerative colitis (UC) and to be involved as proliferative mucosal factors in IBD. However, expression of all REG family genes in IBD is still unclear. Here, we analyzed expression of all REG family genes (REG Iα, REG Iβ, REG III, HIP/PAP, and REG IV) in biopsy specimens of UC and CD by real-time RT-PCR. REG Iα, REG Iβ, and REG IV genes were overexpressed in CD samples. REG IV gene was also overexpressed in UC samples. We further analyzed the expression mechanisms of REG Iα, REG Iβ, and REG IV genes in human colon cells. The expression of REG Iα was significantly induced by IL-6 or IL-22, and REG Iβ was induced by IL-22. Deletion analyses revealed that three regions (- 220 to - 211, - 179 to - 156, and - 146 to - 130) in REG Iα and the region (- 274 to- 260) in REG Iβ promoter were responsible for the activation by IL-22/IL-6. The promoters contain consensus transcription factor binding sequences for MZF1, RTEF1/TEAD4, and STAT3 in REG Iα, and HLTF/FOXN2F in REG Iβ, respectively. The introduction of siRNAs for MZF1, RTEF1/TEAD4, STAT3, and HLTF/FOXN2F abolished the transcription of REG Iα and REG Iβ. The gene activation mechanisms of REG Iα/REG Iβ may play a role in colon mucosal regeneration in IBD.

Tissue factor expression in rheumatoid synovium: a potential role in pannus invasion of rheumatoid arthritis

Angiogenesis, as well as pannus formation within the joint, plays an important role in the erosion of articular cartilage and bone in the pathological process of rheumatoid arthritis (RA). Tissue factor (TF), an essential initiator of the extrinsic pathway of blood coagulation, is also involved in the angiogenesis and the pannus formation of RA progression. In the present study, we used immunofluorescence and confocal scanning methods to characterize TF immunolocalization in RA synovium. We showed that positive staining of TF could be immunolocalized in synoviocytes, CD19(+) B cells and CD68(+) macrophages, whereas weak or negative staining of tissue factor could be found in CD34(+) endothelial cells of neo-vessels, CD3(+) T cells and CD14(+) monocytes in RA synovium tissues. Our study demonstrates a detailed local expression of TF in the rheumatoid synovium, and supports the notion that TF, expressed not only by the synoviocytes themselves, but also the infiltrating CD19(+) B cells and CD68(+) macrophages, is involved in the pannus invasion in the progression of rheumatoid arthritis.

Serum proteome analysis in patients with rheumatoid arthritis receiving therapy with tocilizumab: an anti-interleukin-6 receptor antibody

Rheumatoid arthritis (RA) is a chronic inflammatory disorder of the synovial membrane that results in the destruction of bone and cartilage in affected joints. Tocilizumab is a biological agent and an anti-interleukin-6 (IL-6) receptor monoclonal antibody that blocks IL-6-mediated inflammatory processes in RA patients. In order to identify novel disease-related proteins and candidate biomarkers, we analyzed the changes in the serum proteome profiles of patients with RA who were treated with tocilizumab. Serum samples were collected from the RA patients before and after tocilizumab treatment. Following immunodepletion of major proteins, the proteins were digested and labeled with isobaric tag, iTRAQ reagent. The proteins were identified and quantified using liquid chromatography-tandem mass spectrometry. Among a total of 311 proteins identified, seven were decreased and 16 were increased by tocilizumab treatment. Although some of the proteins are known to be related to RA, several are currently unknown with respect to their relationship to RA and may be involved in the development of this disease. This study is the first to perform a comparative serum proteomic analysis of RA patients treated with tocilizumab. Our results may contribute to the identification of novel disease-related proteins and enhance the understanding of the pathogenesis of RA.