Common variants of genes encoding TLR4 and TLR4 pathway members TIRAP and IRAK1 are effective on MCP1, IL6, IL1β, and TNFα levels in type 2 diabetes and insulin resistance

Inflamm Res. 2019 Sep;68(9):801-814. doi: 10.1007/s00011-019-01263-7. Epub 2019 Jun 20.

Abstract

Objective and design: Type 2 diabetes is a pandemic disease characterized by hyperglycemia, ineffective insulin use, and insulin resistance and affecting 1 in 11 people worldwide. Inflammation-related insulin resistance is thought to play an important role in the etiology of the disease. TLR4 is the central receptor of the natural immune system and has an important role as a trigger of the inflammatory response. The IRAK1 and TIRAP are members of the TLR4 pathway and involved in the TLR4-mediated inflammatory response. Genetic variants in the TLR4 gene or in the IRAK1 and TIRAP genes may have an important role in the development of insulin resistance and type 2 diabetes by disrupting the inflammatory response. In this direction, we aimed to investigate the relationship among TLR4 and IRAK1, TIRAP gene variants, and type 2 diabetes and insulin resistance, and investigate how these variants affect inflammatory factors (TNF-α, IL-6, MCP-1, and IL-1β).

Subjects and methods: In our study, a total of seven variations on the genes of TLR4 (rs4986790, rs4986791), IRAK1 (rs1059703, rs3027898, rs7061789), and TIRAP (rs8177374, rs8177400) were genotyped by the MassARRAY® Iplex GOLD SNP genotyping in 100 type 2 diabetic patients and 100 non-diabetic individual. The TLR4 rs4986790 and rs4986791 variation was confirmed by PCR-RFLP method also. The serum IL1-β, IL6, MCP-1, and TNF-α levels were measured using enzyme-linked immunosorbent assay kits.

Results and conclusion: As a result of our study, no correlation was found among TLR4, IRAK1, and TIRAP gene variants and the risk of type 2 diabetes and insulin resistance. However, TNF-α, IL-6, MCP-1, and IL-1β levels were also associated with diabetes and insulin resistance (p > 0.05). Although the gene variants were not significant in type 2 diabetes and insulin resistance groups, IRAK1, TLR4, and TIRAP gene variants were found to be associated with TNF-α, IL-6, MCP-1, and IL-1β levels.

Keywords: IRAK1; Inflammation; Insulin resistance; TIRAP; TLR4; Type 2 diabetes.

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Chemokine CCL2 / blood
  • Diabetes Mellitus, Type 2 / genetics*
  • Diabetes Mellitus, Type 2 / metabolism
  • Female
  • Genotype
  • Humans
  • Inflammation
  • Insulin Resistance / genetics*
  • Interleukin-1 Receptor-Associated Kinases / genetics*
  • Interleukin-1beta / blood
  • Interleukin-6 / blood
  • Male
  • Membrane Glycoproteins / genetics*
  • Middle Aged
  • Polymorphism, Single Nucleotide*
  • Receptors, Interleukin-1 / genetics*
  • Toll-Like Receptor 4 / genetics*
  • Tumor Necrosis Factor-alpha / blood

Substances

  • CCL2 protein, human
  • Chemokine CCL2
  • IL1B protein, human
  • IL6 protein, human
  • Interleukin-1beta
  • Interleukin-6
  • Membrane Glycoproteins
  • Receptors, Interleukin-1
  • TIRAP protein, human
  • TLR4 protein, human
  • TNF protein, human
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor-alpha
  • IRAK1 protein, human
  • Interleukin-1 Receptor-Associated Kinases

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