The expression of anti-aging protein Klotho is increased during neural differentiation of bone marrow-derived mesenchymal stem cells

Klotho, as an antiaging protein, is involved in the maintenance and differentiation of neuronal or glial cells and, therefore, has been noticed as a potential therapeutic target for neurodegenerative disorders. Expression of Klotho has been examined in different cells and organs, however, our information about the developmental pattern of this protein during differentiation of mesenchymal stem cells (MSCs) into neuron-like cells is limited. In this study, we conducted neural differentiation of mouse bone marrow-derived-MSCs and monitored the expression of Klotho together with selected neuron-specific genes at messenger RNA (mRNA) on days 7 and 14 of differentiation using quantitative real-time PCR. In addition, Klotho status at protein level was evaluated by immunocytochemistry. The results showed a significant change in the morphology of MSCs towards neuron-like cells. These changes were observed with progressive growth and formation of cell connections towards the formation of a chain of neuron-like cells which occurred in the second week of differentiation. Morphological changes were associated with a significant increase in the expression of neuron-specific genes like pax-6, neuN and, neurofilaments (NfL). Likewise, there was an increased expression of Klotho mRNA, and accumulation of Klotho protein in neuronal cell bodies, during the cellular differentiation of MSCs. These findings provided new evidence that neuronal differentiation from the MSCs is associated with increased expression of Klotho. These data may provide insight into the importance of Klotho protein in stem cell differentiation and regeneration in response to cell death in the central nervous system.