Butyrate and forskolin augment host defense, barrier function, and disease resistance without eliciting inflammation

Authors: Robinson, Kelsy; YANG, QING - Oklahoma State University; LI, HONG - Oklahoma State University; ZHANG, LONG - Oklahoma State University; AYLWARD, BRIDGET - University Of Delaware; SUNKARA, LAKSHMI - Clemson University; ARSENAULT, RYAN - Oklahoma State University; ZHANG, GUONLONG - Oklahoma State University

Submitted to: Frontiers in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Increased antimicrobial resistance has created an urgent need for effective antibiotic alternatives capable of maintaining health and productivity of livestock animals. Induction of host defense peptides (HDPs), also known as antimicrobial peptides, by dietary ingredients has emerged as a promising antibiotic-alternative approach. HDPs are an important part of the innate immune system with strong antimicrobial and immunomodulatory activity. Here, we investigated the ability of butyrate, a short-chain fatty acid, and forskolin, a phytochemical, to improve chicken immune status and protect bird health in a necrotic enteritis disease model. Results revealed a synergistic induction of HDP and barrier function genes in chicken cells that was achieved without increasing inflammation. Furthermore dietary supplementation of butyrate and a forskolin-containing plant extract resulted in significant alleviation of necrotic enteritis. These results highlight the potential of butyrate and forskolin to be developed as novel antibiotic alternatives to enhance intestinal health and disease resistance in poultry and other animals.

Technical Abstract: Host defense peptides (HDPs) are an integral part of the innate immune system with both antimicrobial and immunomodulatory activities. Induction of endogenous HDP synthesis is being actively explored as an antibiotic-alternative approach to disease control and prevention. Butyrate, a short-chain fatty acid, and forskolin, a phytochemical, have been shown separately to induce HDP gene expression in human cells. Here, we investigated the ability of butyrate and forskolin to induce the expressions of chicken HDP genes and the major genes involved in barrier function such as mucin 2 (MUC2) and claudin-1 (CLDN1) both in vitro and in vivo. We further evaluated their efficacy in protecting chickens from necrotic enteritis. Additionally, we profiled the transcriptome and global phosphorylation of chicken HD11 macrophage cells in response to butyrate and forskolin using RNA sequencing and a kinome peptide array, respectively. Our results showed a strong synergy between butyrate and forskolin in inducing the expressions of several, but not all, HDP genes. MUC2 gene expression were also synergistically induced in HD11 cells. Importantly, dietary supplementation of butyrate and a forskolin-containing plant extract resulted in significant alleviation of intestinal pathology and colonization of Clostridium perfringens in a synergistic manner in a chicken model of necrotic enteritis. RNA sequencing revealed a preferential increase in HDP and barrier function genes without induction of pro-inflammatory cytokines in response to butyrate and forskolin. The anti-inflammatory and barrier protective properties of butyrate and forskolin was further confirmed by the kinome peptide array. Furthermore, we demonstrated the presence of ICER-mediated negative feedback in HDP induction by butyrate and forskolin. Overall, these results highlight a potential for developing butyrate and forskolin, two natural products, as novel antibiotic alternatives to enhance intestinal health and disease resistance in poultry and other animals.