Lactiplantibacillus plantarum WB4201, WB4202, and WB4203 alleviate gut inflammatory responses and strengthen barrier function in LPS-stimulated HT-29 cells.

Lactiplantibacillus plantarum WB4201, WB4202, and WB4203, which are known to possess probiotic properties, were assessed for their ability to alleviate intestinal inflammation and reinforce epithelial barrier function. These strains exhibited antimicrobial and anti-adhesion properties against pathogens. In HT-29 cells, the strains significantly reduced sodium nitroprusside-induced nitric oxide (NO) overproduction, thus indicating their capacity to mitigate nitrosative stress. In lipopolysaccharide (LPS)-stimulated cells, the strains markedly suppressed pro-inflammatory responses by downregulating interleukin (IL)-8, IL-6, IL-1β, cyclooxygenase-2 (COX-2), and tumor necrosis factor-α (TNF-α). Furthermore, barrier integrity was preserved through the restoration of tight junction proteins, including Occludin, Claudin-1, zonula occludens-1 (ZO-1), and mucin 2 (MUC2). Mechanistic analyses revealed that these protective effects were associated with the inhibition of nuclear factor-kappa B activation and the suppression of mitogen-activated protein kinase phosphorylation cascades. These findings demonstrate the anti-inflammatory and barrier-protective potential of L. plantarum WB4201, WB4202, and WB4203, thus underscoring their potential as probiotic-based interventions for intestinal health.