TWEAK and Fn14 are overexpressed in immune-mediated necrotizing myopathy: implications for muscle damage and repair

Catalpol Research on the Mechanism of Antimyocardial Reperfusion Injury by Regulating the MiR-126/TWEAK-FN14 Pathway: In Vitro and Computer Simulation Studies

The objective of this study was to investigate the mechanism through which catalpol (CAT) exerts its protective effects in the context of myocardial ischemia-reperfusion injury. Preliminary results showed that Cat significantly attenuated oxygen-glucose deprivation/reoxygenation (OGD/R) damage to H9C2 cells, inhibited intracellular reactive oxygen species levels, and downregulated the protein expression of TWEAK and Fn14 post-OGD/R. The intracellular level of miR-126 was downregulated after OGD/R, and this effect was reversed by CAT administration. To further elucidate its mechanisms, a miR-126 inhibitor was used in the H9C2 cells, and the inhibitory effect was validated using real-time fluorescence quantitative polymerase chain reaction (RT-PCR). Following CAT treatment, lactate dehydrogenase (LDH) levels within the cells were assessed. The results revealed that CAT not only decreased LDH levels but also modulated the miR-126/TWEAK-FN14 signaling axis and the expression of inflammatory-related mediators, as evidenced through RT-PCR and Western blot. Additionally, molecular docking (MD) studies suggested that CAT exhibited a strong binding affinity to both the signaling pathway and inflammatory-related components. Furthermore, molecular dynamics simulations (MDS) demonstrated that the CAT-protein complex exhibited high stability, flexibility, and low binding free energy under physiological conditions. Additionally, CAT showed favorable absorption, distribution, metabolism, excretion, and toxicity characteristics. In summary, this study, through in vitro experimentation, confirmed that CAT regulates the miR-126 and inflammatory proteins within the signaling pathway, with these results being further supported by MD and MDS analyses.

Immune-mediated necrotizing myopathy: A comprehensive review of the pathogenesis, clinical features, and treatments

Immune-mediated necrotizing myopathy (IMNM) is a rare and newly recognized autoimmune disease within the spectrum of idiopathic inflammatory myopathies. It is characterized by myositis-specific autoantibodies, elevated serum creatine kinase levels, inflammatory infiltrate, and weakness. IMNM can be classified into three subtypes based on the presence or absence of specific autoantibodies: anti-signal recognition particle myositis, anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase myositis, and seronegative IMNM. In recent years, IMNM has gained increasing attention and emerged as a research hotspot. Recent studies have suggested that the pathogenesis of IMNM is linked to aberrant activation of immune system, including immune responses mediated by antibodies, complement, and immune cells, particularly macrophages, as well as abnormal release of inflammatory factors. Non-immune mechanisms such as autophagy and endoplasmic reticulum stress also participate in this process. Additionally, genetic variations associated with IMNM have been identified, providing new insights into the genetic mechanisms of the disease. Progress has also been made in IMNM treatment research, including the use of immunosuppressants and the development of biologics. Despite the challenges in understanding the etiology and treatment of IMNM, the latest research findings offer important guidance and insights for delving deeper into the disease's pathogenic mechanisms and identifying new therapeutic strategies.

CD163+ macrophage density in perimysial connective tissue associated with prognosis in IMNM

OBJECTIVE

The pathological features of immune-mediated necrotizing myopathy (IMNM) are dominated by the infiltration of macrophages. We aimed to perform a histopathologic semiquantitative analysis to investigate the relationship between macrophage markers and prognosis.

METHODS

Semiquantitative analysis of histologic features was performed in 62 samples of IMNM. Independent risk factors were identified through univariate and multivariate regression analysis. Cluster analysis was performed using the partitioning around the medoids (PAM) method. Decision tree modeling was utilized to efficiently determine cluster labels for IMNM patients. The validity of the developmental cohort was assessed by accuracy in comparison with the validation cohort.

RESULTS

The most enriched groups in patients with IMNM were macrophages expressing CD206 and CD163. In the multivariate logistic regression model, the high density of CD163+ macrophages in perimysial connective tissue increased the risk of unfavorable prognosis (p = 0.025, OR = 1.463, 95% CI: 1.049-2.041). In cluster analysis, patients in Cluster 1, with lower CD163+ macrophage density and inflammatory burden, had a more favorable prognosis. Conversely, patients in Cluster 3, which were enriched for CD163+ macrophages in the perimysial connective tissue, had the most severe clinical features and the worst prognosis. Correlations were found between the density of CD163+ macrophages in connective tissue and symptom duration (R2 = 0.166, p < 0.001), dysphagia (p = 0.004), cardiac involvement (p = 0.021), CK (R2 = 0.067, p = 0.042), CRP (R2 = 0.117, p < 0.001), and ESR (R2 = 0.171, p < 0.001).

CONCLUSION

The density of CD163+ macrophages in perimysial connective tissue may serve as a potential marker for the prediction of IMNM prognosis.