PDGFRA and obstructive sleep apnea syndrome: The involvement of an autocrine loop of PDGF signaling pathway in the pathogenesis of canine OSA was confirmed in other studies, showing the overexpression of cis, the coding gene of PDGFRβ, in a OSA cell line (CO8), and the ability of its supernatant to induce tyrosine phosphorylation and therefore the activation of the PDGFRα and PDGFRβ on murine 3T3 cells (107, 108).