ABSTRACT Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovial inflammation and progressive joint destruction, in which fibroblast‐like synoviocytes (FLSs) play a central pathogenic role. Ferroptosis and oxidative stress‐driven mitochondrial dysfunction have recently been implicated in synovial cell injury during RA progression. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide‐dependent deacetylase, is known to regulate inflammation, redox homeostasis, and cell survival; however, the upstream regulatory mechanisms controlling SIRT1 function and their relevance to ferroptosis in RA remain poorly defined. Primary rat FLSs and a complete Freund's adjuvant (CFA)‐induced adjuvant arthritis (AA) rat model were used. SIRT1 transcription, protein expression, subcellular localization, and enzymatic activity were assessed using quantitative real‐time PCR, Western blotting, immunofluorescence, and enzymatic assays. Oxidative stress, mitochondrial dysfunction, lipid peroxidation, and ferroptosis‐related parameters were evaluated using biochemical assays and fluorescence‐based probes. SUMO1 expression was manipulated by knockdown and overexpression approaches, and the interaction between SUMO1 and SIRT1 was examined by co‐IP.Inflammatory stimulation with IL‐1β impaired SIRT1 transcriptional expression, reduced its nuclear localization, and suppressed its enzymatic activity in FLSs, accompanied by enhanced reactive oxygen species accumulation, mitochondrial dysfunction, lipid peroxidation, and ferroptosis‐related changes. ICA treatment restored SIRT1 expression and activity while alleviating oxidative stress and ferroptotic injury. ICA upregulated SUMO1 expression, while Co‐IP analysis demonstrated an association between SUMO1 and SIRT1. SUMO1‐dependent regulation was associated with increased SIRT1 nuclear localization and enzymatic activity. Disruption of SUMO1 expression or pharmacological inhibition of SIRT1 suppressed the protective effects of ICA in FLSs. Consistent regulatory effects were observed in arthritic rats following ICA administration. These findings support the involvement of SUMO1/SIRT1 regulation in ferroptosis‐related injury and mitochondrial dysfunction in RA‐associated synovial cells. ICA exerts protective effects by restoring coordinated SIRT1 regulation at multiple functional levels, highlighting SIRT1‐centered pathways as potential therapeutic targets for RA.
ABSTRACT Receptor for advanced glycation end‐products (RAGE) was originally identified as a receptor for advanced glycation end‐products; however, it can also bind a broader range of damage‐associated molecular patterns, including S100 proteins, high mobility group box 1, and amyloid‐β. Ligand‐induced RAGE activation promotes receptor oligomerization and recruitment of diaphanous‐related formin‐1, which activates several intracellular cascades, leading to the production of inflammatory mediators and reactive oxygen species. RAGE expression is upregulated in disease‐associated tissues, including adipose tissue in diabetes and microglia and neurons in Alzheimer's disease, and the mechanisms by which RAGE activation contributes to pathogenesis are disease‐specific. The review summarizes the expression and activation of RAGE, and the potential mechanisms through which RAGE contributes to disease pathogenesis. We further discuss current and emerging strategies for modulating RAGE signaling and highlight their therapeutic potential in the prevention and treatment of RAGE‐associated diseases.
ABSTRACT Psoriatic lesions contain sustained inflammatory stress, but whether death‐associated tissue activity is matched by adequate clearance capacity remains poorly defined. To address this, spatial transcriptomics was used to define clearance imbalance in psoriatic skin, with peripheral CITE‐seq assessing circulating myeloid clearance states. Within leucocyte‐rich tissue regions, stress‐death and clearance‐capacity modules identified clearance‐competent niches, marked by matched stress and clearance activity and clearance‐defective niches, marked by stress‐death activity without comparable clearance capacity. This revealed that lesional psoriatic skin shows a selective epidermal clearance imbalance, with increased clearance defect, a higher defective‐to‐competent niche ratio and distinct clearance‐defective transcriptional programming enriched for stress‐processing and stress‐response pathways. The clinical relevance of this epidermal axis was supported by a correlation between epidermal, but not dermal, clearance defect and psoriasis severity. Within this severity‐linked compartment, a preserved monocyte/macrophage‐rich burden masked reduced clearance‐associated programming, indicating that defective epidermal niches retain myeloid‐rich spatial contexts without matched clearance capacity. Peripheral profiling extended this axis to circulation, where psoriatic arthritis showed increased clearance defect scores in mononuclear myeloid cells and a clearance‐defective surface phenotype linked to reduced efferocytosis‐associated capacity. Together, these findings define clearance‐defective psoriatic inflammation as an epidermal tissue programme with convergent circulating myeloid clearance defects in higher burden disease.
Bladder cancer (BC) is the 10th most common cancer worldwide, accounting for approximately 5% of new cases. Several factors contribute to tumor progression, including increased MMP9. Recently, CRISPR-Cas9 and immunotherapy have offered high specificity for treatments; therefore, we edited MMP9 using CRISPR-Cas9 methodology to inhibit metastatic mechanisms and evaluated potential synergy with BCG and anti-PD-L1 therapy. We performed CRISPR-Cas9 gene editing using an RNP complex in the MB49 murine BC cell line. Gene expression of MMPs, integrins, and BAX was analyzed, along with protein expression. Cells were divided into a Scramble control group and CRISPR-Cas9 for the MMP9 edited group (MMP9-/-). Female C57BL/6 mice received orthotopic BC cells (scramble and MMP9-/- groups) treated with BCG and anti-PD-L1. Statistical analyses were performed using t test or ANOVA. MMP9 gene and protein expression were reduced in the MMP9-/- group compared with the scramble group. No differences were observed in other MMPs. Decreased ITGB3, increased BAX gene expression, as well as reduced migration and adhesion to ECM were observed in the MMP9-/- group. Animals in the scramble group showed greater weight loss and lower survival than treated groups. Overall, MMP9 modulated key cellular mechanisms, but did not show synergistic effects with BCG and anti-PD-L1 in vivo.
Advanced glycation end-products (AGEs) arise from non-enzymatic reactions between reducing sugars and proteins, contributing to oxidative stress and metabolic dysfunction. Excessive AGE accumulation is implicated in chronic diabetic complications and may also be relevant to acute metabolic disturbances encountered in emergency medicine. N-acetylcysteine (NAC), a naturally occurring antioxidant found in Allium species, has demonstrated potential to attenuate oxidative and glycation-mediated damage. The effect of NAC on d-ribose-induced glycation of bovine serum albumin (BSA) was investigated using multiple physicochemical and spectroscopic techniques. AGE formation was assessed by measuring hyperchromicity, early glycation products (ketoamines), carbonyl content, hydroxymethylfurfural (HMF) levels, and fluorescent AGEs. The protective effect of NAC was further evaluated by determining free lysine and arginine contents. Protein aggregation and conformational changes were analyzed using Congo Red binding and fluorescence assays including thioflavin-T and 1-anilinonaphthalene-8-sulfonic acid. NAC significantly inhibited d-ribose-mediated glycation of BSA in a concentration-dependent manner. Treatment with NAC resulted in reduced hyperchromicity, decreased ketoamine formation, and lower carbonyl, HMF, and fluorescent AGE levels. NAC preserved protein integrity by maintaining higher free lysine and arginine contents. In addition, NAC markedly attenuated glycation-induced protein aggregation, as evidenced by reduced Congo Red binding and diminished thioflavin-T and ANS fluorescence, with maximal protection observed at 300 μM. NAC exhibits pronounced anti-glycation and anti-aggregation effects by limiting oxidative stress and glycation-mediated protein modification. These findings demonstrate that NAC effectively attenuates d-ribose-induced glycation and protein aggregation in vitro and provide mechanistic insights into its anti-glycation properties through multiple complementary biochemical mechanisms. Further studies are warranted to evaluate its biological relevance in more complex experimental models.
