The effect of growth hormone-induced cellular behavior and signaling properties on induced cellular senescence in human mesenchymal stem cells

Senescence is associated with a decline in physiological function, which is accompanied by onset of diseases. Growth hormone (GH) is a class of growth-promoting cytokines with reduced secretion in aging populations. However, the effect of senescence on GH bioactivity is not fully understood in human mesenchymal stem cells (hMSCs). In this work, GH-induced cellular behavior and intracellular signaling transduction were explored in senescent hMSCs. Therefore, hMSCs were used to establish a senescence model by H2O2 treatment for this study. First, we investigated the effects of cellular senescence on the cell behavior of GH. The experimental results suggested that GH could not be internalized into the nucleus, and a significant reduction in GH internalization into the cytoplasm was observed in senescent hMSCs compared to the control group. Second, the effect of cellular senescence on GH-mediated intracellular signaling pathways was investigated by Western blotting. For this, the signaling molecule activation of Janus kinase 2 (JAK2)/signal transducer and activator transcription (STAT) stimulated by GH was detected. Our data indicated that the signaling intensity of p-JAK2, p-STAT5, p-STAT3 and p-STAT1 was considerably weakened. Taken together, these findings provide important insights into the impaired effects of cellular senescence on the biological activity of GH.