cells Review Mitochondrial MicroRNAs in Aging and Neurodegenerative Diseases Albin John 1, Aaron Kubosumi 1 and P. Hemachandra Reddy 1,2,3,4,5,* 1 Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA;
[email protected] (A.J.);
[email protected] (A.K.) 2 Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA 3 Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA 4 Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA 5 Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA * Correspondence:
[email protected]; Tel.: +1-806-743-3194 Received: 7 April 2020; Accepted: 27 May 2020; Published: 28 May 2020 Abstract: MicroRNAs (miRNAs) are important regulators of several biological processes, such as cell growth, cell proliferation, embryonic development, tissue differentiation, and apoptosis. Currently, over 2000 mammalian miRNAs have been reported to regulate these biological processes. A subset of microRNAs was found to be localized to human mitochondria (mitomiRs). Through years of research, over 400 mitomiRs have been shown to modulate the translational activity of the mitochondrial genome. While miRNAs have been studied for years, the function of mitomiRs and their role in neurodegenerative pathologies is not known. The purpose of our article is to highlight recent findings that relate mitomiRs to neurodegenerative diseases, including Alzheimer’s, Parkinson’s, and Huntington’s. We also discuss the involvement of mitomiRs in regulating the mitochondrial genome in age-related neurodegenerative diseases.