Differential expression analysis of balding and nonbalding dermal papilla microRNAs in male pattern baldness with a microRNA amplification profiling method.

BACKGROUND:   Male pattern baldness or androgenetic alopecia is a common disorder affecting almost 50% of men throughout their lifetime, with androgens and genetics having significant contributing aetiologies. In contrast to the positive regulatory effect of androgens on body hair growth, they are thought to alter scalp hair follicle behaviour pathophysiologically, leading to male pattern baldness. However, the exact mechanisms of this paradoxical action have not yet been elucidated. The role of microRNAs, a novel group of noncoding RNAs impacting almost every aspect of biology, health and human diseases, has been documented in hair follicle formation. In addition, their deregulation in cancer of the prostate, a target organ of androgens, has also been well established.

OBJECTIVES: To investigate the possible contribution of microRNAs in the pathophysiology of male pattern baldness.

METHODS: We initially screened microRNA expression profiles of balding and nonbalding hair follicle papillae with a sensitive microRNA cloning method, microRNA amplification profiling, and statistically analysed significant differentially expressed microRNAs in balding relative to nonbalding dermal papillae, with real-time polymerase chain reaction as a confirmatory method to quantify expression in eight individuals affected with the disorder.

RESULTS:   We detected the significant upregulation of miR-221, miR-125b, miR-106a and miR-410 in balding papilla cells.

CONCLUSIONS:   We found four microRNAs that could participate in the pathogenesis of male pattern baldness. Regarding the strong therapeutic potential of microRNAs and the easy accessibility of hair follicles for gene therapy, microRNAs are possible candidates for a new generation of revolutionary treatments.