MT-RNR2 and neurodegenerative disease: The main aims of the present review article are (i) to present recent findings of research concerning neuroprotective/cytoprotective actions of HN, a 24-mer peptide belonging to the MDP family and (ii) to shed further light on the potential of HN to serve as a core template molecule for the eventual development of novel therapeutics, such as suitable HN analogues, against neurodegenerative diseases.