Search

Endoplasmic reticulum (ER) stress, pyroptosis, and apoptosis are critical molecular events in the occurrence and progress of renal ischemia reperfusion (I/R) injury. Naringenin (4 ′ ,5,7-trihydroxyflavanone) is one of the most widely consumed flavonoids with powerful antioxidant and anti-inflammatory activities. However, whether naringenin is able to relieve renal I/R injury and corresponding mechanisms have not been fully clarified. This study was aimed at exploring its role and relevant mechanisms in renal I/R injury. The C57Bl/6 mice were randomly assigned to receive administration with naringenin (50 mg/kg/d) or sterile saline (1.0 mL/d) for 3 d by gavage and suffered from renal I/R surgery. One specific ER stress inhibitor, 4-phenylbutyric acid (4-PBA, 100 mg/kg/d), was intraperitoneally administered to validate the regulation of ER stress on pyroptosis and apoptosis. Cultured HK-2 cells went through the process of hypoxia/reoxygenation (H/R) to perform cellular experiments with the incubation of naringenin (200 μM), 4-PBA (5 mM), or brusatol (400 nM). The animal results verified that naringenin obviously relieved renal I/R injury, while it refined renal function and attenuated tissue structural damage. Furthermore, naringenin treatment inhibited I/R-induced ER stress as well as pyroptosis and apoptosis as indicated by decreased levels of specific biomarkers such as GRP78, CHOP, caspase-12, NLRP3, ASC, caspase-11, caspase-4, caspase-1, IL-1β, GSDMD-N, BAX, and cleaved caspase-3 in animals and HK-2 cells. Besides, the upregulated expression of Nrf2 and HO-1 proteins after naringenin treatment suggested that naringenin activated the Nrf2/HO-1 signaling pathway, which was again authenticated by the usage of brusatol (Bru), one unique inhibitor of the Nrf2 pathway. Importantly, the application of 4-PBA showed that renal I/R-generated pyroptosis and apoptosis were able to be regulated by ER stress in vivo and in vitro. In conclusion, naringenin suppressed ER stress by activating Nrf2/HO-1 signaling pathway and further alleviated pyroptosis and apoptosis to protect renal against I/R injury.

Clear cell renal cell carcinoma (ccRCC), the major histopathological subtype of renal cancer, is sensitive to ferroptosis. MIT-domain containing protein 1 (MITD1) has been reported to play an important role in hepatocellular carcinoma, while it remains unclear whether MITD1 is involved in ccRCC. Based on available data in The Cancer Genome Atlas, we found the expression of MITD1 increased through bioinformatics analysis and high MITD1 expression suggests a poor prognosis. And we validated that MITD1 expressed significantly in ccRCC through Western blot analysis. Then, we further compared the proliferation and migration capacity of ccRCC before and after MITD1 knockdown and further explored the effect of MITD1 knockdown on ferroptosis. The results indicated that MITD1 knockdown inhibited ccRCC cell proliferation and migration and induced ferroptosis in ccRCC. Furthermore, we found and analyzed the key molecule TAZ which was involved in ferroptosis caused by MITD1 knockdown. Subsequent overexpression experiments demonstrated that MITD1 knockdown induced ferroptosis and suppressed tumor growth and migration through the TAZ/SLC7A11 pathway. In summary, our study revealed the role of MITD1 in the ferroptosis of ccRCC and provided a novel target for ccRCC treatment.