TGFBR1 and Miyoshi myopathy: Inhibition of TGFβ activity using specific TGFβR1 inhibitor SB-431542 significantly reduced the secretion of CXCL13 in MM-MΦ co-culture medium (Fig. 4E) and interfered with CXCL13 gene expression induction in MM cells co-incubated with macrophages (Fig. 4F).