Inhibiting PKCβ2 protects HK-2 cells against meglumine diatrizoate and AGEs-induced apoptosis and autophagy

Trans-sodium crocetinate suppresses apoptotic and oxidative response following myoglobin-induced cytotoxicity in HEK-293 cells

Objectives

Rhabdomyolysis (RM) is a serious fatal syndrome. The RM leads to acute kidney injury (AKI) as a fatal complication. The belief is that RM-induced AKI is triggered by myoglobin (MB). MB activates oxidative and apoptotic pathways. Trans-sodium crocetinate (TSC) is obtained from saffron. It has anti-oxidant and renoprotective effects. This research was designed to assess the mechanisms of MB-induced cytotoxicity in HEK-293 cells (human embryonic kidney cells) as well as the possible effects of TSC against MB-induced cytotoxicity.

Materials and Methods

HEK-293 cells were exposed to diverse concentrations of TSC (2.5, 5, 10, 20, 40, 80, and 100 µM) for 24 hr. Then, MB (9 mg/ml) was added to the cells. After 24 hr, cell viability was measured through MTT, and the values of ROS generation were calculated using DCFH-DA assay. Also, autophagy and apoptosis markers in cells were assessed by western blot analysis.

Results

MB decreased viability and increased ROS levels in HEK-293 cells. However, pretreatment of HEK-293 cells with TSC for 24 hr reduced the cytotoxicity and ROS production caused by MB. Furthermore, MB enhanced both the apoptosis (cleaved caspase-3 and Bax/Bcl-2 ratio) and autophagy markers (LC3II/I ratio and Beclin-1) in HEK-293 cells. On the other hand, TSC pretreatment condensed the levels of autophagy and apoptosis criteria in response to MB cytotoxicity.

Conclusion

TSC has a positive effect in preventing MB-induced cytotoxicity in HEK-293 cells by increasing anti-oxidant activity and regulation of apoptotic and autophagy signaling pathways.

Advanced glycation end products promote the progression of chronic kidney diseases by targeting calpain 6

Advanced glycation end products (AGEs) are produced by glycosylation or oxidation of proteins and lipids and are tightly involved in the chronic kidney disease (CKD) process. Calpain 6 (CAPN6) is a non-classical calpain that has been reported to be overexpressed in CKD. This study aimed to explore the effects of AGEs in CKD progress and their correlation with CAPN6. AGEs production was measured using ELISA. The CCK-8 assay was used to test cell proliferation. mRNA and protein levels were tested using qRT-PCR and western blot. The progress of glycolysis was tested by calculating the ATP and ECAR content in HK-2 cells. The expression of AGEs and CAPN6 was significantly increased in patients with CKD3, CKD4, and CKD5. AGEs treatment inhibited cell proliferation and glycolysis and accelerated apoptosis. Additionally, CAPN6 knockdown effectively reversed the effects of AGEs in HK-2 cells. In addition, overexpressed CAPN6 played similar role to AGEs, which suppressed cell proliferation and glycolysis and facilitated apoptosis. Moreover, the administration of 2-DG, a glycolysis inhibitor, counteracted the effects of CAPN6 silencing in HK-2 cells. Mechanistically, CAPN6 interacts with NF-κB and PDTC reduced CAPN6 expression in HK-2 cells. This investigation revealed that AGEs facilitate CKD development in vitro by modulating the expression of CAPN6.

Effect of trans-sodium crocetinate on contrast-induced cytotoxicity in HEK-293 cells

Objectives

Contrast media (CM) are used for diagnostic or therapeutic intervention purposes in medicine. The main adverse reaction after the administration of CM is contrast-induced nephropathy (CIN). This complication is the third cause of renal failure after hospital treatment. The current study is designed to investigate the possible protective effect of trans-sodium crocetinate (TSC), derived from carotenoid crocetin, against sodium amidotrizoate/meglumine amidotrizoate (SAMA) induced cytotoxicity in HEK-293 cells.

Materials and Methods

HEK-293 cells were incubated with different concentrations of TSC (1, 2.5, 5, 10, 25, and 50 µM, for 48 hr) and then SAMA (7 mgI/ml, for 24 hr) was added. The cell viability, intracellular ROS, and phosphatidyl serine exposure were detected by MTT assay, DCFH-DA, and annexin V-FITC/PI method, respectively. The P-ERK/ERK ratio, apoptosis (Bax/Bcl-2 ratio and cleaved caspase-3), and autophagy (LC3 II/I ratio and beclin-1) markers in cells were evaluated by the western blot method.

Results

The exposure of HEK-293 cells to SAMA reduced viability, increased apoptotic cells, enhanced ROS production, and subsequently decreased P-ERK/ERK ratio. Similarly, SAMA enhanced apoptosis (Bax/Bcl-2 ratio and cleaved caspase-3) and autophagy (LC3 II/I ratio and beclin-1) markers in HEK-293 cells. The pretreatment of cells with TSC before exposure to SAMA significantly attenuated contrast-induced cytotoxicity. TSC reduced intracellular ROS production and activated the phosphorylation of ERK. In addition, TSC decreased the levels of apoptosis and autophagy proteins.

Conclusion

The pretreatment of HEK-293 cells with TSC can decrease contrast-induced cytotoxicity through antioxidant effect and modulate ERK, apoptosis, and autophagy pathways.

Dexmedetomidine protects cardiac microvascular endothelial cells from the damage of ogd/r through regulation of the pparδ-mediated autophagy

BACKGROUND

Dexmedetomidine (Dex) exerts an effective therapeutic role in numerous diseases associated with ischemia/reperfusion (I/R) injury via its anti-apoptosis properties. Therefore, this study explores the cardioprotective effects of Dex in cardiac microvascular endothelial cells (CMECs) in response to oxygen-glucose deprivation and re-oxygenation (OGD/R) injury and its potential mechanism.

MATERIAL AND METHODS

CMECs were pretreatment with different concentration of Dex, then exposed to OGD/R. Cell viability was measured with CCK-8 assay. Apoptosis was evaluated by flow cytometry, and apoptosis-related protein was determined by Western blot. Autophagy was assessed by transmission electron microscopy and autophagy-related proteins. Besides, the role peroxisome proliferator-activated receptors (PPARδ) in Dex-mediated anti-apoptosis property was validated with agonist and antagonist.

RESULTS

OGD/R significantly decreased cell viability, increased reactive oxygen species, caused disorder of autophagy, and increased apoptosis in CMECs. Dex enhanced the viability of the OGD/R-treated CMECs and effectively decreased reactive oxygen species production. Autophagy in CMECs was activated by Dex, as evidenced by the increase in the ratio of LC3B-II/I, expression level of Beclin1 and number of autophagosomes in the OGD/R-induced CMECs. The mechanistic investigation indicated that PPARδ antagonist GW501516 aggravated cell damage following OGD/R, while PPARδ agonist GW6471 partly abolished the Dex-mediated protective effects.

CONCLUSIONS

Dex activated the PPARδ-AMPK-PGC-1α pathway-mediated autophagy in CMECs, therefore to inhibit excessive apoptosis induced by OGD/R. Dex may potentially be a therapeutic intervention for myocardial I/R injury.