Heat-Killed Lacticaseibacillus paracasei Repairs Lipopolysaccharide-Induced Intestinal Epithelial Barrier Damage via MLCK/MLC Pathway Activation

Nutrients. 2023 Apr 4;15(7):1758. doi: 10.3390/nu15071758.

Abstract

Intestinal epithelial barrier function is closely associated with the development of many intestinal diseases. Heat-killed Lacticaseibacillus paracasei (HK-LP) has been shown to improve intestinal health and enhance immunity. However, the function of HK-LP in the intestinal barrier is still unclear. This study characterized the inflammatory effects of seven HK-LP (1 μg/mL) on the intestinal barrier using lipopolysaccharide (LPS) (100 μg/mL)-induced Caco-2 cells. In this study, HK-LP 6105, 6115, and 6235 were selected, and their effects on the modulation of inflammatory factors and tight junction protein expression (claudin-1, zona occludens-1, and occludin) were compared. The effect of different cultivation times (18 and 48 h) was investigated in response to LPS-induced intestinal epithelial barrier dysfunction. Our results showed that HK-LP 6105, 6115, and 6235 improved LPS-induced intestinal barrier permeability reduction and transepithelial resistance. Furthermore, HK-LP 6105, 6115, and 6235 inhibited the pro-inflammatory factors (TNF-α, IL-1β, IL-6) and increased the expression of the anti-inflammatory factors (IL-4, IL-10, and TGF-β). HK-LP 6105, 6115, and 6235 ameliorated the inflammatory response. It inhibited the nuclear factor kappa B (NF-κB) signaling pathway-mediated myosin light chain (MLC)/MLC kinase signaling pathway by downregulating the Toll-like receptor 4 (TLR4)/NF-κB pathway. Thus, the results suggest that HK-LP 6150, 6115, and 6235 may improve intestinal health by regulating inflammation and TJ proteins. Postbiotics produced by these strains exhibit anti-inflammatory properties that can protect the intestinal barrier.

Keywords: heat-killed Lacticaseibacillus paracasei; inflammation; intestinal epithelial barrier; probiotics; tight junction.

MeSH terms

  • Anti-Inflammatory Agents / pharmacology
  • Caco-2 Cells
  • Hot Temperature
  • Humans
  • Intestinal Mucosa / metabolism
  • Lacticaseibacillus
  • Lipopolysaccharides* / pharmacology
  • Myosin Light Chains
  • Myosin-Light-Chain Kinase / metabolism
  • Myosin-Light-Chain Kinase / pharmacology
  • NF-kappa B* / metabolism
  • Phosphorylation
  • Tight Junctions / metabolism

Substances

  • NF-kappa B
  • Lipopolysaccharides
  • Myosin Light Chains
  • Myosin-Light-Chain Kinase
  • Anti-Inflammatory Agents