Periostin deficiency attenuates kidney fibrosis in diabetic nephropathy via improving pancreatic β-cell dysfunction

Diabetic nephropathy (DN) is associated with kidney fibrosis. A previous study revealed that periostin (POSTN) contributes to kidney fibrosis. This study examined the role of POSTN in DN. The urinary concentrations of POSTN and TNC increased according to the severity of DN in human samples. Streptozotocin (STZ) was administered after unilateral nephrectomy (UNXSTZ) to induce DN in both wild-type and Postn-null mice. Four experimental groups were generated: wild-type sham (WT sham), wild-type UNXSTZ (WT STZ), Postn-null sham (KO sham), Postn-null UNXSTZ (KO STZ). After 20 weeks, the KO STZ group had lower urine albumin excretion, glomerular sclerosis, and interstitial fibrosis than the WT STZ group. Also, it had lower expression of fibrosis markers, including TNC. The KO STZ group showed better glucose regulation than the WT STZ model. Furthermore, the KO STZ group preserved pancreatic islet integrity and insulin expression significantly. We stimulated INS-1 cells with streptozotocin and evaluated the viability of these cells. The anti-POSTN antibody treatment of INS-1 cells with streptozotocin resulted in higher cell viability than treatment with streptozotocin alone. The absence of POSTN in DN contributes to renal fibrosis alleviation by improving pancreatic β-cell function. Additionally, there is an association between POSTN and TNC.