Peripheral artery disease (PAD) is a disease of atherosclerosis in the lower extremities. PAD carries a massive burden worldwide, while diagnosis and treatment options are often lacking. One of the key points of research in recent years is the involvement of microRNAs (miRNAs), which are short 20-25 nucleotide single-stranded RNAs that can act as negative regulators of post-transcriptional gene expression. Many of these miRNAs have been discovered to be misregulated in PAD patients, suggesting a potential utility as biomarkers for PAD diagnosis. miRNAs have also been shown to play an important role in many different pathophysiological aspects involved in the initiation and progression of the disease including angiogenesis, hypoxia, inflammation, as well as other cellular functions like cell proliferation and migration. The research on miRNAs in PAD has the potential to lead to a whole new class of diagnostic tools and treatments.

This study investigates ferroptosis in the context of peripheral artery disease (PAD), a vascular disease characterized by atherosclerosis of the lower extremities. Muscle atrophy and increased oxidative stress are hallmarks of PAD and correlate with worse clinical outcomes. Given ferroptosis’ association with oxidative stress, we explored its role in PAD myopathy by examining gene and protein markers related to metabolic pathways implicated in ferroptosis using both human PAD patients and cultured myotubes. Intermittent claudication (IC) PAD patients, critical limb ischemia (CLI) PAD patients, and non-PAD controls were recruited for this study. Calf muscle biopsies were analyzed for gene expression using qPCR, and protein levels were determined by Western blotting. Cultured myotubes treated with the ferroptosis inducer erastin provided an in vitro comparison. Results demonstrated upregulation of ferroptosis markers such as lipid peroxidation and PTGS2 gene expression in the muscle of CLI PAD patients compared to controls. Increased expression of ferroptosis-related genes HMOX1, ACSL4, ELAVL1, and Beclin-1 was also observed. Protein analysis showed trends consistent with gene expression in some ferroptosis markers. The increase in ferroptosis markers in CLI PAD patients, particularly in iron metabolism and autophagy pathways, suggests ferroptosis contributes to PAD myopathy.

Introduction Mitoxyperiosis is a recently described process in which innate immune and metabolic stress drive mitochondria-delivered oxidative damage at the plasma membrane, culminating in lytic cell death (mitoxyperilysis). Whether human tumors, including clear cell renal cell carcinoma (ccRCC), harbor molecular states related to this pathway is unknown.MethodsWe prespecified an equal-weight Mitoxy score comprising BAK1, BAX, and BID, whose loss protects against mitoxyperiosis, and SLC7A11 as a redox-context extension. The score was characterized in TCGA-KIRC and tested without reweighting in CPTAC ccRCC, E-MTAB-1980, multiregion TRACERx Renal, single-cell and spatial datasets, and the JAVELIN Renal 101 and CheckMate 025 trials. Specificity testing used purity adjustment and 10,000 expression-matched random four-gene modules. We also reanalyzed the source mitoxyperiosis RNA-seq experiment (GSE235046).ResultsHigher Mitoxy scores tracked higher grade in all four clinical cohorts and, variably, stage. In TCGA-KIRC, the grade association exceeded 99.36% of matched random modules (empirical P=0.0065) and persisted after purity and global-expression adjustment. In GSE235046, the score was induced by combined lipopolysaccharide and carbon starvation and reversed by Torin (interaction P=1.2x10⁻6; reversal P=8.0x10⁻⁶; joint matched-module P=0.0351). TRACERx showed regional heterogeneity yet robust patient-level associations, and adjusted enrichment in punctuated evolutionary tumors. In JAVELIN Renal 101 and CPTAC, the score correlated with a MYD88/TNF/TLR2/TLR4 inflammatory program that single-cell data localized to myeloid cells, although spatial coupling was inconsistent. Exploratory treatment associations were context dependent, not universally predictive.ConclusionAggressive ccRCC harbors a reproducible mitoxyperiosis-related transcriptional state anchored to the source experimental response.