Virginia Egea
Hypoxia, or reduced oxygen availability, triggers a spectrum of adaptive responses across tissues, including angiogenesis, metabolic reprogramming, and modulation of survival pathways. Central to these adaptations are hypoxia-regulated microRNAs (miRNAs), hypoxamiRs, which fine-tune gene expression in a context-dependent manner. HypoxamiRs are transcriptionally regulated by hypoxia-inducible factors (HIFs), tissue-specific transcriptional programs, and microenvironmental cues, enabling precise responses to hypoxia. HypoxamiRs exhibit distinct expression profiles across tissues, reflecting their specialized roles. In ischemic tissue, they activate angiogenic and cytoprotective programs, while in metabolically active or malignant tissues, they rewire energy production and promote survival. This tissue specificity underlies their dual function as both regulators of physiological adaptation and drivers of pathology in chronic hypoxia. Increasingly, hypoxamiRs are being recognized as non-invasive biomarkers and therapeutic targets in diseases such as cancer, cardiovascular disorders, and fibrosis. Compared to canonical hypoxia pathways, hypoxamiRs offer a versatile and finely tunable layer of regulation. This review presents a unified framework in which hypoxamiRs emerge not merely as downstream effectors of HIF signaling but as integrative architects at the intersection of oxygen sensing, epigenetic remodeling, and cellular identity. Their coordinated regulatory functions make them promising tools for precision medicine in hypoxia-related diseases. Understanding how hypoxamiRs operate across tissues and pathologies may unlock new diagnostic and therapeutic strategies for complex, oxygen-sensitive conditions.