Microcystin-LR Induces Apoptosis via NF-κB /iNOS Pathway in INS-1 Cells

Author: Ji Yong   Lu Gao   Chen Guoqiang   Huang Bin   Zhang Xian   Shen Kai   Wu Song  

Publisher: MDPI

E-ISSN: 1422-0067|12|7|4722-4734

ISSN: 1422-0067

Source: International Journal of Molecular Sciences, Vol.12, Iss.7, 2011-07, pp. : 4722-4734

Access to resources Favorite

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Cyanobacterial toxins, especially the microcystins, are found in eutrophied waters throughout the world, and their potential to impact on human and animal health is a cause for concern. Microcystin-LR (MC-LR) is one of the common toxic microcystin congeners and occurs frequently in diverse water systems. Recent work suggested that apoptosis plays a major role in the toxic effects induced by MC-LR in hepatocytes. However, the roles of MC-LR in pancreatic beta cells have not been fully established. The aim of the present study was to assess possible in vitro effects of MC-LR on cell apoptosis in the rat insulinoma cell line, INS-1. Our results demonstrated that MC-LR promoted selectively activation of NF-κB (increasing nuclear p50/p65 translocation) and increased the mRNA and protein levels of induced nitric oxide synthase (iNOS). The chronic treatment with MC-LR stimulated nitric oxide (NO) production derived from iNOS and induced apoptosis in a dose dependent manner in INS-1 cells. Meanwhile, this effect was inhibited by the NF-κB inhibitor PDTC, which reversed the apoptosis induced by MC-LR. Our observations indicate that MC-LR induced cell apoptosis via an iNOS-dependent pathway. A well-known nuclear transcription factor, NF-κB, is activated and mediates intracellular nitric oxide synthesis. We suggest that the apoptosis induced by chronic MC-LR in vivo presents a possible cause of β-cell dysfunction, as a key environmental factor in the development of diabetes mellitus.

Related content