Lactobacillus salivarius metabolite succinate enhances chicken intestinal stem cell activities via the SUCNR1-mitochondria axis

Poult Sci. 2024 Dec 31;104(2):104754. doi: 10.1016/j.psj.2024.104754. Online ahead of print.

Abstract

The activity of intestinal stem cells (ISCs) can be modulated by Lactobacillus, which subsequently affects the mucosal absorptive capacity. However, the underlying mechanisms remain unclear. In this study, a total of 189 Hy-Line Brown chickens (Gallus) were randomly assigned to one of seven experimental groups (n = 27 per group). These groups included a control group, a vehicle group (MRS group), a Lactobacillus salivarius group, a L. salivarius supernatant group, and three succinate treatment groups with various dosages. Each group was further subdivided into three replicates, with 9 chickens per replicate. The results indicate that the administration of Lactobacillus salivarius supernatant to laying hens notably increased the mRNA abundance of the amino acid transporters oligopeptide transporter 1 (PepT1) and sodium-dependent neutral amino acid transporter (B0AT). Metabolomic analyses indicated that the supernatant contains a high concentration of organic acids. Among them, succinate could enhance mRNA abundance of PepT1, B0AT and excitatory amino acid transporters 3 (EAAT3) both in vivo and in vitro. Accordingly, succinate could accelerate intestinal epithelial turnover, as indicated by the increased levels of cyclin-dependent kinase 2 (Cdk2) mRNA and proliferating cell nuclear antigen protein (PCNA), as well as ISC differentiation-related protein leucine-rich repeat containing G protein-coupled receptor 5 (LGR5). Furthermore, succinate treatment was shown to elevate the levels of mitochondrial fusion proteins optic atrophy 1 (OPA1) and translocase of outer mitochondrial membrane 20 (TOMM20), resulting in increased local ATP levels. However, pretreatment with NF-56-EJ40, a succinate receptor antagonist, attenuated the effects of succinate on OPA1, TOMM20, and ATP levels, alone with the reducing LGR5 and PCNA levels. Collectively, succinate, a metabolite of L. salivarius, activates the SUCNR1-mitochondria axis in ISCs, facilitating mitochondrial ATP synthesis, promoting ISC activity, and ultimately enhancing mucosal absorptive capacity.

Keywords: Intestinal stem cell; Lactobacillus salivarius; Mitochondria; Succinate.