Purple Sweet Potato Polysaccharide Exerting an Anti-inflammatory Effect via a TLR-Mediated Pathway by Regulating Polarization and Inhibiting the Inflammasome Activation

Abstract

Purple sweet potato polysaccharide (PSPP-1) is a novel glucan; this study aimed to examine the anti-inflammatory effect of PSPP-1 and elucidate its potential mechanisms. Lipopolysaccharide (LPS)-induced RAW264.7 was used as the model of inflammation, cell viability, and levels of nitric oxide (NO), reactive oxygen species (ROS), and calcium ion (Ca 2+ ) were analyzed. ELISA and qPCR were used to assess the productions and mRNA expression of cytokines, and Western blotting was used to assess protein expressions in the TLR-mediated pathway, macrophage polarization, and inflammasome activation. The results demonstrated PSPP-1 inhibited cell proliferation and markedly decreased NO, ROS, and Ca 2+ levels. Moreover, PSPP-1 suppressed the secretions and mRNA expressions of pro-inflammatory cytokines and increased those of anti-inflammatory cytokines. Furthermore, PSPP-1 could exert anti-inflammatory effects through different pathways mediated by both TLR2 and TLR4, which modulated the expressions of essential proteins in the myeloid differentiation factor 88 (MyD88)-dependent and toll/IL-1 receptor domain-containing adaptor-inducing interferon-β (TRIF)-dependent signaling pathways. PSPP-1 even regulated the polarization of M1/M2 macrophages and inhibited the nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation. These findings indicate that PSPP-1 can suppress LPS-induced inflammation via multiple pathways and may be a potential agent for therapeutic inflammation-related pathophysiological processes and disorders.

Gastroprotective effects of polysaccharides from purple sweet potato (Ipomoea batatas (L.) Lam) on an ethanol-induced gastric ulcer via regulating immunity and activating the PI3K/Akt/Rheb/mTOR pathway

“…Purple sweet potatoes ( Ipomoea batatas (L.) Lam), a special variety of sweet potato, are a kind of sweet potato with a purple root color. 19 The polysaccharides of the purple sweet potato ( Ipomoea batatas (L.) Lam) have various biological activities, such as antioxidant, 20 antitumor, 21,22 immunomodulatory, 23 anti-inflammatory, 24,25 liver protection 26–28 and regulation of the intestinal flora. 29 At present, related research on whether the polysaccharides of purple sweet potato alleviate gastric ulcers and the mechanism is still to be reported.…”