Palmitic Acid-Induced Podocyte Apoptosis via the Reactive Oxygen Species-Dependent Mitochondrial Pathway

Abstract

Background/Aims: Chronic kidney disease (CKD) is often accompanied by hyperlipidemia, which accelerates progression of the disease. Podocyte injury can lead to dysfunction of the glomerular filtration barrier, which is associated with proteinuria, a risk marker for the progression of CKD. Our previous studies demonstrated that palmitic acid (PA) can induce podocyte apoptosis; however, the underlying mechanisms are unclear. In the present study, we investigated the specific molecular mechanisms of PA-induced apoptosis in cultured podocytes. Methods: We cultured mouse podocytes and treated them with PA. Then, cell viability was measured using the Cell Counting Kit-8 colorimetric assay, lipid uptake was assessed by Oil Red O staining and boron-dipyrromethene staining, apoptosis was measured by flow cytometry, mitochondrial injury was assessed by JC-1 staining and transmission electron microscopy, and mitochondrial production of reactive oxygen species (ROS) was evaluated by fluorescence microscopy using the MitoSOX Red reagent. The effects of PA on the mitochondria-mediated caspase activation pathway were investigated by examining the expression of caspase-8, cleaved caspase-9, cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), B-cell lymphoma 2 (Bcl-2), Bax, Bid, cytochrome c, and Fas-associated protein with death domain (FADD) using western blotting. The translocation of Bax and cytochrome c were detected by immunofluorescence. Results: PA treatment significantly increased lipid accumulation and induced podocyte apoptosis. We investigated whether the two primary apoptosis signaling pathways (death receptor-mediated pathway and mitochondria-mediated pathway) were involved in the execution of PA-induced podocyte apoptosis, and found that the levels of FADD, caspase-8, and Bid did not significantly change during this process. Meanwhile, PA treatment induced an increase in Bax protein expression and a decrease in Bcl-2 protein expression, with Bax translocation to the mitochondria. Furthermore, PA treatment induced mitochondrial impairment, and triggered the release of cytochrome c from the mitochondria to cytosol, with a concomitant dose-dependent increase in the levels of cleaved caspase-9, cleaved caspase-3, and PARP. Meanwhile, PA treatment increased mitochondrial production of ROS, and the mitochondria-targeted antioxidant mitoTEMPO significantly ameliorated PA-induced podocyte apoptosis. Conclusion: Our findings indicated that PA induced caspase-dependent podocyte apoptosis through the mitochondrial pathway, and mitochondrial ROS production participated in this process, thus potentially contributing to podocyte injury

Soy isoflavones improve the oxidative stress induced hypothalamic inflammation and apoptosis in high fat diet-induced obese male mice through PGC1-alpha pathway

“…Moreover, we found significantly increased reactive oxygen species (ROS) accumulation in N42 cells after PA treatment by fluorescent dihydroethidium (Eth) labeling, while ROS accumulation was decreased after daidzein or genistein treatment ( Figure 5B, 5C). Excessive palmitic acid has been implicated in the induction of apoptosis in a large variety of cell types [26,27]. We found that PA significantly induced apoptosis by Hoechst 33342 staining, while PA/daidzein or PA/genistein combined AGING…”

Berberine alleviates palmitic acid‑induced podocyte apoptosis by reducing reactive oxygen species‑mediated endoplasmic reticulum stress

“…BBR alleviates PA-induced podocyte death and apoptosis. according to our previous study, Pa at a concentration of 150 µmol/l induced marked lipid accumulation and apoptosis of podocytes (22); therefore, 150 µmol/l PA was selected in the present study to treat podocytes. To evaluate the effects of BBr on Pa-induced cell death, podocytes were treated with Pa and different concentrations of BBr for 24 h. using the ccK-8 cell viability assay, a significant increase in podocyte death was observed in the Pa group compared with in the control group, whereas a significant amelioration of PA-induced cell death was observed when cells were pretreated with BBr at a concentration of 4, 8 and 16 µmol/l (Fig.…”

“…1a). cleaved-caspase 3 is an important marker of apoptosis, which is one of the main types of cell death (22). The expression levels of cleaved-caspase 3 were detected using western blotting ( Fig.…”

Arsenic sulfide amplifies JQ1 toxicity via mitochondrial pathway in gastric and colon cancer cells

“…Mitochondrial depolarization elevates mitochondrial outer membrane permeabilization, facilitating the leakage of cytochrome c from dysfunctional mitochondria into the cytoplasm, which activates the caspase cascade and mitochondria-mediated apoptosis. 27 To further confirm whether mitochondrial pathway was involved in the apoptosis induced by the combination treatment, we then performed subcellular fractionations in these four GC and colon cancer cells. We observed that the protein level of cytochrome c was markedly increased in the cytosolic fraction of cells co-treated with AS and JQ1, accompanied by a reduction of their levels in membrane fraction, as determined by Western blot analysis ( Figure 6 ).…”