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Open Access Highly Accessed Research article

High glucose increases LPS-induced DC apoptosis through modulation of ERK1/2, AKT and Bax/Bcl-2

Mei Feng1, Juan Li2, Jun Wang3, Chunyan Ma1, Yulian Jiao1, Yan Wang4, Jie Zhang1, Qiuying Sun5, Ying Ju6, Ling Gao1* and Yueran Zhao1*

Author Affiliations

1 Central Laboratory, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China

2 Department of Obstetrics and Gynecology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China

3 Jinan Central Hospital, Affiliated with Shandong University, Jinan, China

4 Department of Occupational Environmental Health Monitoring and Evaluation, Shandong Center for Disease Control and Prevention, Jinan, China

5 Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China

6 Department of Clinical Laboratory, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China

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BMC Gastroenterology 2014, 14:98  doi:10.1186/1471-230X-14-98

Published: 28 May 2014

Abstract

Background

This study investigates the effect of glucose on the LPS-induced apoptosis of dendritic cells in the intestinal tract of mice and the dendritic cell line DC2.4.

Methods

Flow cytometry was used to detect dendritic cell apoptosis both in vivo and in vitro. Hoechst 33258 staining was used to detect the morphological changes characteristic of apoptotic nuclei. Expression of apoptosis related proteins was investigated by western blot analysis and immunohistochemistry.

Results

Pretreatment with a high concentration of glucose increased apoptosis of LPS-treated dendritic cells both in vivo and in vitro at 24 h. No effect was evident at the earlier time points of 15 min and 6 h in vitro. Furthermore, at 24 hours the expression of the survival proteins AKT, ERK and Bcl-2 was decreased, while the expression of the proapoptotic protein Bax was increased. AKT, ERK, Bcl-2 and Bax were mainly located in the cytoplasm by immunohistochemistry.

Conclusions

These results suggest that high glucose concentrations might prime dendritic cells for apoptosis induced by LPS in the intestinal tract through upregulating the expression of Bax and downregulating the expression of AKT, ERK and Bcl-2. Therefore, this study may give clues to understanding the immunological mechanism behind gastrointestinal complications in diabetes mellitus.

Keywords:
Dendritic cell; Apoptosis; Diabetes mellitus; Glucose; Gastrointestinal complications diabetes