2. Academic Validation
  3. 4-Hydroxyisoleucine relieves inflammation through iRhom2-dependent pathway in co-cultured macrophages and adipocytes with LPS stimulation

4-Hydroxyisoleucine relieves inflammation through iRhom2-dependent pathway in co-cultured macrophages and adipocytes with LPS stimulation

  • BMC Complement Med Ther. 2020 Dec 9;20(1):373. doi: 10.1186/s12906-020-03166-1.
Cong Zhou 1,  Rui Chen 1,  Feng Gao 2,  Jiaoyue Zhang 2,  Furong Lu 3
Affiliations

Affiliations

  • 1 Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
  • 2 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
  • 3 Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. lufurong@hust.edu.cn.
PMID: 33298044 DOI: 10.1186/s12906-020-03166-1
Abstract

Background: 4-Hydroxyisoleucine (4-HIL) is an active ingredient extracted from Trigonella foenum-graecum L., a Chinese traditional herbal medicine, which exerts the efficacy of anti-obesity and anti-diabetes. We previously reported that 4-HIL potentiates anti-inflammatory and anti-insulin resistance effects through down-regulation of TNF-α and TNF-α converting Enzyme (TACE) in 3 T3-L1 adipocytes and HepG2 cells. In the present study, we further investigate the effects and mechanisms of 4-HIL on obesity-induced inflammation in RAW264.7 macrophages and 3 T3-L1 adipocytes co-culture system.

Methods: RAW264.7 macrophages and 3 T3-L1 adipocytes were co-cultured to mimic the microenvironment of adipose tissue. siRNA-iRhom2 transfection was performed to knockdown iRhom2 expression in RAW264.2 macrophages. The mRNA and protein expression of iRhom2 and TACE were measured by real-time quantitative PCR (RT-qPCR) and western blotting. The production of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), IL-6 and IL-10 were evaluated by ELISA. The ratio of M2/M1 was detected by flow cytometry.

Results: 4-HIL significantly repressed the mRNA and protein levels of iRhom2 and TACE in RAW264.7 macrophages after LPS stimulated. Meanwhile, the levels of pro-inflammatory cytokines, including TNF-α, MCP-1, and IL-6, were substantially suppressed by 4-HIL in the co-culture system. Moreover, the level of anti-inflammatory cytokine IL-10 was increased significantly by 4-HIL in the co-culture system after LPS stimulation. Additionally, the ratio of M2/M1 was also increased by 4-HIL in the co-culture system after LPS stimulation. Finally, these effects of 4-HIL were largely enhanced by siRNA-iRhom2 transfection.

Conclusion: Taken together, our results indicated that obesity-induced inflammation was potently relieved by 4-HIL, most likely through the iRhom2-dependent pathway.

Keywords

3 T3-L1 adipocytes; 4-hydroxyisoleucine; Obesity-induced inflammation; RAW264.7 macrophages; Trigonella foenum-graecum L.; iRhom2.

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