This study aimed to elucidate the response of bovine satellite cells to heat exposure. Satellite cells were isolated from Holstein bulls and subjected to varying temperatures. Transcriptional, proteomic, and proliferative changes were assessed. Following extreme heat exposure, cells exhibited upregulated expression of heat shock proteins (HSPs; HSP70, HSP90, HSP20) and paired box gene 7 (Pax7). Conversely, the expression of myogenic factor 5 (Myf5) and paired box gene 3 (Pax3), key regulators of myogenesis, decreased under conditions of extreme heat. Notably, downregulation of HSP27 expression using siRNA restored Myf5 expression to normal levels, implying an association between HSP27 and Myf5 in the modulation of satellite cell properties during heat exposure. Our results validated the direct binding of HSP27 to Myf5, substantiating its role as a molecular chaperone. These findings underscore the elevation of HSPs, and alteration of early myogenic regulatory factors implicated in muscle development upon exposure to extreme heat. HSP27 functions as a molecular chaperone by engaging with Myf5, thereby influencing the division or differentiation of satellite cells during heat stress (HS). This study contributes to the advancement of our comprehension regarding the muscular physiology of heat-stressed animals, while clarifying the intricate molecular mechanisms governing the response of satellite cells to HS.

Read the full article in the Journal of Animal Science.