Glutamic acid promotes hair growth in mice
Glutamic Acid is the main excitatory neurotransmitter in neurons. Abnormal distributions of the glutamic acid receptors have been shown in hyper proliferative models such as psoriasis and skin regeneration. However, the biological function of glutamic acid in the skin remains unclear. Using ex vivo, in vivo and in silico approaches, we showed for the first time that exogenous glutamic acid promotes hair growth and keratinocyte proliferation. Topical application of glutamic acid decreased expression of genes related to apoptosis signaling in the skin. Also, we showed Glutamic acid increased viability and proliferation in cultured human keratinocyte. For the first time, we identified the excitotoxic GA concentration and we provided evidence for the existence of a novel skin signaling pathway mediated by a neurotransmitter controlling keratinocyte and hair follicle proliferation. In perspective, we anticipate our results could be the starting point to elucidate how exogenous glutamic acid from food intake or even endogenous GA from neuropsychiatric disorders modulate skin diseases.