Mitochondria-Targeting microRNAs (mitomiRs): Potential Mediators of Environmental Mitoepigenetics in Mammalian Spermatogenesis

The field of mitoepigenetics involves the investigation of modifications in mitochondrial DNA (mtDNA), genomic DNA that encodes mitochondrial proteins, and the expression of RNAs that regulate mitochondrial gene expression but do not alter the DNA sequence. This area of research is growing rapidly and has substantial relevance to male mammalian fertility. Among the known mitoepigenetic mechanisms, mitochondrial microRNAs (mitomiRs) have attracted substantial attention due to their potential roles in modulating mitochondrial gene expression in response to environmental stressors. Since many problems with male fertility are known to result from environmental factors, there has been increasing interest in studying epigenetic mechanisms that contribute to male reproductive function. This review explores the current literature regarding different mitoepigenetic mechanisms and their implications for male mammalian fertility, focusing primarily on the known and potential involvement of mitomiRs in model species and humans. Understanding mitoepigenetics may contribute to the development of non-invasive diagnostic biomarkers and individualized therapeutic approaches to male infertility due to their stability in body fluids, tissue specificity, and sensitivity to disease states.