Protective effects of deferoxamine on lead-induced cardiotoxicity in rats

Lead-induced cardiomyocytes apoptosis by inhibiting gap junction intercellular communication via modulating the PKCα/Cx43 signaling pathway

OBJECTIVE

The aim of this study was to investigate the regulatory mechanism of Pb regulates gap junction intercellular communication to induced apoptosis in H9c2 cells.

METHODS

H9c2 cell line is used as the research object in this study, and treated with different concentrations of Pb acetate. Subsequently, Cell viability was measured by the Cell Counting Kit-8 (CCK-8) assay. The levels of lactate dehydrogenase (LDH), aspartate transaminase (AST) and creatine kinase-MB (CK-MB) in the supernatants were measured using respective commercial enzyme-linked immune sorbent assay (ELISA) kits. Western blot was used to detect the expression of apoptosis-related protein in H9c2 cells in each group. Quantitative RT-PCR Analysis Total RNA was extracted from frozen H9c2 cells using Trizol reagent, the PKCα and Cx43 in the supernatant of H9c2 cells was determined by the BCA protein detection kit.

RESULTS

H9c2 cells increased release of cardiac enzymes (LDH, AST, and CK-MB) and decreased cell survival rate, and the Cx43, p-Cx43, PKCα and p-PKCα protein levels showed a dose-dependent decrease after Pb treatment. PKCα was activated with PMA, the relative expression level of Cx43 protein increased significantly, the expression of Bcl-2 increased and Bax and Cyt-c decreased compared with Pb exposure group, and the myocardial enzymes (LDH, AST, and CK-MB) in cell culture supernatant decreased compared with Pb exposure group, indicating that the degree of cell damage was alleviated. Results showed that Pb inhibited PKCα activity, decreased the expression of total Cx43 and P-Cx43 protein, and aggravated myocardial injury.

CONCLUSIONS

Pb decrease gap junction intercellular communication, which induce apoptosis in H9c2 cells by inhibiting the PKCα/Cx43 signaling pathway.

Deferoxamine B: A Natural, Excellent and Versatile Metal Chelator

Deferoxamine B is an outstanding molecule which has been widely studied in the past decade for its ability to bind iron and many other metal ions. The versatility of this metal chelator makes it suitable for a number of medicinal and analytical applications, from the well-known iron chelation therapy to the most recent use in sensor devices. The three bidentate hydroxamic functional groups of deferoxamine B are the centerpiece of its metal binding ability, which allows the formation of stable complexes with many transition, lanthanoid and actinoid metal ions. In addition to the ferric ion, in fact, more than 20 different metal complexes of deferoxamine b have been characterized in terms of their chemical speciation in solution. In addition, the availability of a terminal amino group, most often not involved in complexation, opens the way to deferoxamine B modification and functionalization. This review aims to collect and summarize the available data concerning the complex-formation equilibria in solutions of deferoxamine B with different metal ions. A general overview of the progress of its applications over the past decade is also discussed, including the treatment of iron overload-associated diseases, its clinical use against cancer and neurodegenerative disorders and its role as a diagnostic tool.

Lead-induced cardiomyocytes apoptosis by inhibiting gap junction intercellular communication via autophagy activation

Lead (Pb) is one of the most common heavy metal contaminants in the environment. Pb can cause pathophysiological changes in several organ systems, including the cardiovascular system, but the molecular mechanism remains elusive. The study aimed to study the effects of Pb on Gap junction intercellular communication (GJIC) and its role in Pb-induced apoptosis. The present study aims to determine whether Pb-induced autophagy promotes apoptosis of rat cardiac myocytes (H9c2 cells) by downregulating GJIC using CCK-8 Kit, scrape loading/dye transfer assay, Annexin V/PI assays, Western blot analysis and double-immunofluorescence experiments. The results showed that Pb elicited cytotoxicity in a time- and concentration-dependent manner and led to increased apoptosis in a concentration-dependent manner in H9c2 cells. Pb also reduced GJIC in H9c2 cells in a concentration-dependent manner through the downregulation of connexin (Cx) 43. Inhibition of gap junctions by gap junction blocker carbenoxolone disodium (CBX) resulted in increased apoptosis. Furthermore, Pb increased autophagy in a concentration-dependent manner in H9c2 cells, decreasing the distribution of Cx43 on the cell membrane, and targeted Cx43 to autophagosome via light chain 3 (LC3). However, autophagy inhibitor 3-Methyladenine (3-MA) can slow down the downregulation of Cx43 induced by Pb in H9c2 cells. In conclusion, our results provide evidence that Pb-decreased GJIC promotes apoptosis in cardiomyocytes. This is probably because of the fact that Pb-induced autophagy exacerbates GJIC inhibition and downregulation of Cx43.