Molecular insights of p-benzoquinone-induced red blood cell dysfunction: probable implications to cigarette smoke-associated pathologies

Cigarette smoke (CS) is a complex mixture of numerous chemicals, including p-benzosemiquinone (pBSQ), which oxidizes to p-benzoquinone (pBQ) in the lungs of smokers and enters circulation. Despite its high reactivity, the direct impact of pBQ on human red blood cells (RBC) remains underexplored. Herein, we investigated the molecular insights into how pBQ compromises human RBC physiology and its role in mediating CS-associated pathologies by integrating redox biochemistry, membrane integrity, and omics-based approaches. Our findings reveal that pBQ disrupted redox homeostasis, evidenced by glutathione depletion, elevated reactive oxygen species, lipid peroxidation, and reduced antioxidant enzyme activity. pBQ also triggered methemoglobin formation, hemoglobin aggregation, and reduced oxygen-binding capacity. Biophysical analysis of RBCs revealed reduced membrane fluidity, alterations in membrane proteins and lipids, disrupted zeta potential, and sedimentation dynamics, suggesting altered deformability, an indication of impaired microvascular transit. Untargeted metabolomics and lipidomics profiling revealed metabolic reprogramming and remodeling of the membrane lipids. Depletion of polyunsaturated fatty acids alongside accumulation of saturated species in the membrane points toward membrane stiffening. Pathway analysis highlighted perturbations in fatty acid biosynthesis and redox homeostasis. Disease enrichment analysis linked these changes to hypertension and other pathologies that are previously linked to redox imbalance and CS exposure. Notably, NAC co-treatment mitigated these effects, preserving RBC integrity and redox homeostasis. These findings underscore that pBQ is a critical mediator of CS-induced RBC dysfunction and establish a mechanistic link to its contribution to smoking-associated complications.