Basic Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Jan 15, 2023; 14(1): 48-61
Published online Jan 15, 2023. doi: 10.4239/wjd.v14.i1.48
Gut region-specific TNFR expression: TNFR2 is more affected than TNFR1 in duodenal myenteric ganglia of diabetic rats
Bence Pál Barta, Benita Onhausz, Afnan AL Doghmi, Zita Szalai, János Balázs, Mária Bagyánszki, Nikolett Bódi
Bence Pál Barta, Benita Onhausz, Afnan AL Doghmi, Zita Szalai, János Balázs, Mária Bagyánszki, Nikolett Bódi, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged 6726, Hungary
Author contributions: Bódi N and Bagyánszki M designed the study; Barta BP, Bódi N, Onhausz B, AL Doghmi A, Balázs J and Szalai Z performed the research; Barta BP and Bódi N analyzed the data; Bódi N wrote the original draft; Barta BP and Bagyánszki M reviewed and edited the original draft; Bódi N and Bagyánszki M prepared the figures; all authors have read and approve the final manuscript.
Supported by Hungarian National Research, Development and Innovation Fund Projects, No. GINOP-2.3.3-15-2016-00006; Hungarian NKFIH Fund Project, No. FK131789 (to Bódi N); János Bolyai Research Scholarship of the Hungarian Academy of Sciences (to Bódi N); ÚNKP-21-5 - New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research, Development and Innovation Fund (to Bódi N); and Gedeon Richter Plc Centenary Foundation (to Bódi N).
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the National Scientific Ethical Committee on Animal Experimentation (National Competent Authority), with the license number XX./1636/2019.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: Dataset available from the corresponding author at bmarcsi@bio.u-szeged.hu.
ARRIVE guidelines statement: The authors have read the ARRIVE Guidelines, and the manuscript was prepared and revised according to the ARRIVE Guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Mária Bagyánszki, PhD, Associate Professor, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, Szeged 6726, Hungary. bmarcsi@bio.u-szeged.hu
Received: July 5, 2022
Peer-review started: July 5, 2022
First decision: July 31, 2022
Revised: August 16, 2022
Accepted: October 27, 2022
Article in press: October 27, 2022
Published online: January 15, 2023
Processing time: 188 Days and 19.6 Hours
Abstract
BACKGROUND

Cytokines are essential in autoimmune inflammatory processes that accompany type 1 diabetes. Tumor necrosis factor alpha plays a key role among others in modulating enteric neuroinflammation, however, it has a dual role in cell degeneration or survival depending on different TNFRs. In general, TNFR1 is believed to trigger apoptosis, while TNFR2 promotes cell regeneration. The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy, however, the expression and alterations of different TNFRs in the gastrointestinal tract has not been reported.

AIM

To investigate the TNFR1 and TNFR2 expression in myenteric ganglia and their environment in different intestinal segments of diabetic rats.

METHODS

Ten weeks after the onset of hyperglycemia, gut segments were taken from the duodenum, ileum and colon of streptozotocin-induced (60 mg/body weight kg i.p.) diabetic (n = 17), insulin-treated diabetic (n = 15) and sex- and age-matched control (n = 15) rats. Myenteric plexus whole-mount preparations were prepared from different gut regions for TNFR1/HuCD or TNFR2/HuCD double-labeling fluorescent immunohistochemistry. TNFR1 and TNFR2 expression was evaluated by post-embedding immunogold electron microscopy on ultrathin sections of myenteric ganglia. TNFRs levels were measured by enzyme-linked immun-osorbent assay in muscle/myenteric plexus-containing (MUSCLE-MP) tissue homogenates from different gut segments and experimental conditions.

RESULTS

A distinct region-dependent TNFRs expression was detected in controls. The density of TNFR1-labeling gold particles was lowest, while TNFR2 density was highest in duodenal ganglia and a decreased TNFRs expression from proximal to distal segments was observed in MUSCLE-MP homogenates. In diabetics, the TNFR2 density was only significantly altered in the duodenum with decrease in the ganglia (0.32 ± 0.02 vs 0.45 ± 0.04, P < 0.05), while no significant changes in TNFR1 density was observed. In diabetic MUSCLE-MP homogenates, both TNFRs levels significantly decreased in the duodenum (TNFR1: 4.06 ± 0.65 vs 20.32 ± 3.1, P < 0.001; TNFR2: 11.72 ± 0.39 vs 15.91 ± 1.04, P < 0.01), which markedly influenced the TNFR2/TNFR1 proportion in both the ganglia and their muscular environment. Insulin treatment had controversial effects on TNFR expression.

CONCLUSION

Our findings show diabetes-related region-dependent changes in TNFR expression and suggest that TNFR2 is more affected than TNFR1 in myenteric ganglia in the duodenum of type 1 diabetic rats.

Keywords: Tumor necrosis factor alpha receptors; Myenteric ganglia; Enteric neurons; Neuronal environment; Diabetes; Insulin

Core Tip: Our findings demonstrate an intestinal segment-specific expression of TNFRs in myenteric ganglia and their muscular environment in type 1 diabetic rats. TNFR2 density was significantly altered only in the duodenum of diabetics with a decrease in the ganglia, while no significant changes in TNFR1 were observed. In diabetic muscle/myenteric plexus homogenates, the levels of both TNFRs decreased significantly in the duodenum, which markedly influenced the TNFR2/TNFR1 proportion in both the ganglia and muscular environment. These results highlight that TNFR2 is more affected than TNFR1 in myenteric ganglia in the duodenum of diabetic rats. Insulin treatment had controversial effects on TNFR expression.