COL4A3 and chronic kidney disease: CKD-induced osteocyte apoptosis was partially rescued by overexpression of DMP1 in B6 Col4a3−/− mice (Fig. 3g–h), consistent with previous findings that DMP1 has anti-apoptotic effects.20 We further tested the effects of DMP1 in DMP1-overexpressing and control MC3T3-E1 osteoblasts cultures that we treated with increasing concentrations of the pro-inflammatory cytokine TNFα, which is known to induce osteoblast apoptosis.34 In support of anti-apoptotic effects of DMP1, cells overexpressing DMP1 cells were protected against TNFα-induced apoptosis (Figure S2a-b).