Renoprotective effect of a novel combination of 6-gingerol and metformin in high-fat diet/streptozotocin-induced diabetic nephropathy in rats via targeting miRNA-146a, miRNA-223, TLR4/TRAF6/NLRP3 inflammasome pathway and HIF-1α

Biol Res. 2024 Jul 20;57(1):47. doi: 10.1186/s40659-024-00527-9.

Abstract

Background: MiRNA-146a and miRNA-223 are key epigenetic regulators of toll-like receptor 4 (TLR4)/tumor necrosis factor-receptor-associated factor 6 (TRAF6)/NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome pathway, which is involved in diabetic nephropathy (DN) pathogenesis. The currently available oral anti-diabetic treatments have been insufficient to halt DN development and progression. Therefore, this work aimed to assess the renoprotective effect of the natural compound 6-gingerol (GR) either alone or in combination with metformin (MET) in high-fat diet/streptozotocin-induced DN in rats. The proposed molecular mechanisms were also investigated.

Methods: Oral gavage of 6-gingerol (100 mg/kg) and metformin (300 mg/kg) were administered to rats daily for eight weeks. MiRNA-146a, miRNA-223, TLR4, TRAF6, nuclear factor-kappa B (NF-κB) (p65), NLRP3, caspase-1, and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA expressions were measured using real-time PCR. ELISA was used to measure TLR4, TRAF6, NLRP3, caspase-1, tumor necrosis factor-alpha (TNF-α), and interleukin-1-beta (IL-1β) renal tissue levels. Renal tissue histopathology and immunohistochemical examination of fibronectin and NF-κB (p65) were performed.

Results: 6-Gingerol treatment significantly reduced kidney tissue damage and fibrosis. 6-Gingerol up-regulated miRNA-146a and miRNA-223 and reduced TLR4, TRAF6, NF-κB (p65), NLRP3, caspase-1, TNF-α, IL-1β, HIF-1α and fibronectin renal expressions. 6-Gingerol improved lipid profile and renal functions, attenuated renal hypertrophy, increased reduced glutathione, and decreased blood glucose and malondialdehyde levels. 6-Gingerol and metformin combination showed superior renoprotective effects than either alone.

Conclusion: 6-Gingerol demonstrated a key protective role in DN by induction of miRNA-146a and miRNA-223 expression and inhibition of TLR4/TRAF6/NLRP3 inflammasome signaling. 6-Gingerol, a safe, affordable, and abundant natural compound, holds promise for use as an adjuvant therapy with metformin in diabetic patients to attenuate renal damage and stop the progression of DN.

Keywords: 6-Gingerol; Diabetic nephropathy; MiRNA-146a; MiRNA-223; NLRP3 inflammasome; TLR4.

MeSH terms

  • Animals
  • Catechols* / pharmacology
  • Diabetes Mellitus, Experimental* / metabolism
  • Diabetic Nephropathies* / drug therapy
  • Diabetic Nephropathies* / metabolism
  • Diabetic Nephropathies* / prevention & control
  • Diet, High-Fat*
  • Drug Therapy, Combination
  • Fatty Alcohols / pharmacology
  • Hypoglycemic Agents / pharmacology
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Inflammasomes* / drug effects
  • Inflammasomes* / metabolism
  • Kidney / drug effects
  • Kidney / metabolism
  • Kidney / pathology
  • Male
  • Metformin* / administration & dosage
  • Metformin* / pharmacology
  • MicroRNAs* / drug effects
  • MicroRNAs* / metabolism
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects
  • Streptozocin
  • Toll-Like Receptor 4 / metabolism

Substances

  • Catechols
  • Fatty Alcohols
  • gingerol
  • Hypoglycemic Agents
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Inflammasomes
  • Metformin
  • MicroRNAs
  • MIRN146a microRNA, rat
  • MIRN223 microRNA, rat
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, rat
  • Streptozocin
  • Tlr4 protein, rat
  • Toll-Like Receptor 4