Promoted Interaction of Nuclear Factor-κB with Demethylated Cystathionine-β-Synthetase Gene Contributes to Gastric Hypersensitivity in Diabetic Rats
- Hong-Hong Zhang1,2,*,
- Ji Hu1,*,
- You-Lang Zhou2,3,*,
- Shufen Hu2,
- Yong-Meng Wang2,
- Wei Chen3,
- Ying Xiao1,
- Li-Yen Mae Huang4,
- Xinghong Jiang2, and
- Guang-Yin Xu1,2
- 1Division of Endocrinology, the Second Affiliated Hospital, Soochow University, Suzhou 215000, P.R. China,
- 2Institute of Neuroscience, Suzhou Key Laboratory of Pain Research and Therapy, Department of Neurobiology, Soochow University, Suzhou 215123, P.R. China,
- 3Hand Surgery Research Center, Department of Hand Surgery, Affiliated Hospital of Nantong University, Nantong 226001, P.R. China, and
- 4Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555-1069
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Author contributions: G.-Y.X. designed research; H.-H.Z., Y.-L.Z., S.H., Y.-M.W., and W.C. performed research; J.H., Y.-L.Z., S.H., Y.-M.W., and Y.X. analyzed data; H.-H.Z., J.H., L.-Y.M.H., X.J., and G.-Y.X. wrote the paper.
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↵*H.-H.Z., J.H., and Y.-L.Z. contributed equally to this work.
Abstract
Patients with long-standing diabetes frequently demonstrate gastric hypersensitivity with an unknown mechanism. The present study was designed to investigate roles for nuclear factor-κB (NF-κB) and the endogenous H2S-producing enzyme cystathionine-β-synthetase (CBS) signaling pathways by examining cbs gene methylation status in adult rats with diabetes. Intraperitoneal injection of streptozotocin (STZ) produced gastric hypersensitivity in female rats in response to gastric balloon distention. Treatment with the CBS inhibitor aminooxyacetic acid significantly attenuated STZ-induced gastric hypersensitivity in a dose-dependent fashion. Aminooxyacetic acid treatment also reversed hyperexcitability of gastric-specific dorsal root ganglion (DRG) neurons labeled by the dye DiI in diabetic rats. Conversely, the H2S donor NaHS enhanced neuronal excitability of gastric DRG neurons. Expression of CBS and p65 were markedly enhanced in gastric DRGs in diabetic rats. Blockade of NF-κB signaling using pyrrolidine dithiocarbamate reversed the upregulation of CBS expression. Interestingly, STZ treatment led to a significant demethylation of CpG islands in the cbs gene promoter region, as determined by methylation-specific PCR and bisulfite sequencing. STZ treatment also remarkably downregulated the expression of DNA methyltransferase 3a and 3b. More importantly, STZ treatment significantly enhanced the ability of cbs to bind DNA at the p65 consensus site, as shown by chromatin immunoprecipitation assays. Our findings suggest that upregulation of cbs expression is attributed to cbs promoter DNA demethylation and p65 activation and that the enhanced interaction of the cbs gene and p65 contributes to gastric hypersensitivity in diabetes. This finding may guide the development and evaluation of new treatment modalities for patients with diabetic gastric hypersensitivity.
- Received March 11, 2013.
- Revision received April 11, 2013.
- Accepted April 16, 2013.
- Copyright © 2013 the authors 0270-6474/13/339028-11$15.00/0
