Integrin heterodimer α9 β1 is localized on the surface of porcine spermatogonial stem cells in the undifferentiated state.

A previous study found that undifferentiated porcine spermatogonial stem cells (SSCs) did not adhere to tenascin C, indicating that the integrin α9 and β1 subunits are inactive on the surface of porcine SSCs. However, that study used recombinant tenascin C without FNIII-like repeats. Therefore, this study re-evaluated the existence of integrin α9 β1 actively functioning on the plasma membrane of porcine SSCs using full-length native tenascin C with FNIII-like repeats. The localization and function of the integrin heterodimer were confirmed using immunocytochemistry, attachment and antibody inhibition assays. In undifferentiated porcine SSCs with integrin α9 β1 on the cell surface, adhesion to native tenascin C was significantly higher compared with cells lacking native tenascin C and functional blocking of integrin α9 β1 significantly inhibited the attachment to native tenascin C compared with no functional blocking. Accordingly, we confirmed that the integrin α9 and β1 subunits function as an active heterodimer on the surface of porcine SSCs in the undifferentiated state.