Dietary pomegranate supplement alleviates murine pancreatitis by modulating Nrf2-p21 interaction and controlling apoptosis to survival switch

J Nutr Biochem. 2019 Apr:66:17-28. doi: 10.1016/j.jnutbio.2018.12.009. Epub 2018 Dec 21.

Abstract

Dietary supplementation of polyphenol-rich pomegranate extract (POMx) has been shown to have anti-oxidant and anti-inflammatory activities. Here, we evaluate the efficacy of POMx in mitigating pancreatitis in mice and provide a mechanistic outline of the process. Age-matched male Swiss albino mice were injected with Lipopolysaccharide (LPS) and given POMx supplement alone or in combination with LPS. After 4 weeks of treatment histological scoring for pancreatic edema and vacuolization was performed. Serum insulin levels were estimated and the glucose tolerance test (IPGTT) data revealed that POMx reduced inflammation induced hyperglycemia in mice. Analysis of TLR4, IκB expression, and NF-κB nuclear translocation, and concentrations of IL-6 and TNFα showed that POMx is able to modulate the molecular instigators of inflammatory responses. Annexin V assay indicated that POMx protects against inflammation-mediated apoptosis in the pancreas. Expression profile of SAPK/JNK pathway, p53, Bax, Bcl-2 and Caspase-3 validate an apoptotic to survival shift in POMx treatment group. Co-immunoprecipitation studies show that POMx stabilizes p21 and Nrf2 interaction and increases its nuclear translocation. The study also proves that the nuclear fraction of Nrf2 is able to bind to the Bcl-2 promoter and activate an anti-apoptotic program. The findings of our study underline an anti-inflammatory, anti-oxidative and anti-apoptotic role of POMx and provide a mechanistic idea of how POMx confers protection during pancreatitis.

Keywords: Apoptosis; Bcl-2; Nrf2; Oxidative stress; Pancreatitis; Pomegranate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology
  • Caspase 3 / genetics
  • Caspase 3 / metabolism
  • Cell Survival / drug effects
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism*
  • Cytokines / blood
  • Dietary Supplements
  • Lipopolysaccharides / toxicity
  • Male
  • Mice
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism*
  • Oxidative Stress / drug effects
  • Pancreas / pathology
  • Pancreatitis / chemically induced
  • Pancreatitis / diet therapy*
  • Pancreatitis / metabolism
  • Pancreatitis / pathology
  • Plant Extracts / pharmacology*
  • Pomegranate / chemistry*
  • Proto-Oncogene Proteins c-bcl-2 / genetics

Substances

  • Cdkn1a protein, mouse
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cytokines
  • Lipopolysaccharides
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, mouse
  • Plant Extracts
  • Proto-Oncogene Proteins c-bcl-2
  • Casp3 protein, mouse
  • Caspase 3