Milk-derived extracellular vesicles attenuate the Nuclear Factor kappa light-chain-1 enhancer of activated B cells (NF-κB) pathway

Abstract

Pro-inflammation may influence developmental trajectories and long-term health outcomes in offspring and is closely associated with early-life stress exposures. Milk-derived extracellular vesicles (MEVs), are a group of non-nutritive bioactive components of mammalian milk that provide anti-inflammatory benefits to offspring during lactation to potentially offset altered developmental outcomes of gestational stress. Nuclear Factor Kappa-light-chain-enhancer of activated B cells (NF-κB) is a central signal transduction cascade that regulates DNA transcription, inflammation, cytokine/chemokine production, and apoptosis. Specifically, NF-κB activation leads to the formation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome. My thesis focuses on characterizing how MEVs interacts with NF-κB pathway and mitigate NLRP3 inflammasome formation and thereby help reduce pro-inflammation at the cellular and systems level. The thesis is comprised of two main objectives. Objective 1: A single dose of interferon-γ (IFN-γ) was used to induce acute polarization and pro-inflammation in human microglia clone 3 (HMC3) cells. MEVs anti-inflammatory effects were tested at 6, 12, and 24-hours post-MEV supplementation at the transcript and protein level. Objective 2: Perinatal diet stress was used to induce chronic, systemic pro-inflammation in neonatal rats. Female breeders were placed on a high-fat diet to induce an obesogenic phenotype and the neonates were treated with MEVs via oral gavage during key periods of early postnatal development. Hypothalamus and liver were assessed at the transcript and protein level. We found that MEVs attenuate NF-κB pathway activation and NLRP3 inflammasome formation at critical checkpoints in vitro and in vivo, with a more robust inhibition in response to acute stress in HMC3 cells.