Mohan Zhou

Ulcerative colitis (UC) is a chronic inflammatory disease characterized by persistent colonic inflammation, excessive oxidative stress, and impaired barrier function. Transition metal-based nanoparticles offer promising antioxidant platforms to address oxidative stress-related pathologies. To overcome the poor gastrointestinal stability of the potent dietary antioxidant epigallocatechin gallate (EGCG), we utilized zinc-coordinated EGCG (EGCG-Zn) nanoparticles (NPs), which function as a transition metal–phenolic network, to achieve sustained colonic release and overcome the poor gastrointestinal stability of free EGCG. The therapeutic efficacy and underlying mechanisms were evaluated in dextran sulfate sodium (DSS)-induced colitis in mice. Oral administration of EGCG-Zn NPs effectively reduced oxidative stress, suppressed pro-inflammatory cytokine production, alleviated colitis symptoms, and repaired the intestinal mucus and mechanical barriers. Mechanistically, transcriptomic analysis revealed that EGCG-Zn NPs pretreatment markedly reversed DSS-induced transcriptional alterations. Integrated K-means clustering and KEGG enrichment analyses further demonstrated that these protective effects were mediated by down-regulating inflammation-associated genes and up-regulating tight junction proteins, primarily involving the modulation of calcium signaling, T-cell differentiation, and the PI3K-Akt, Wnt, NF-κB, and TNF pathways. Collectively, these findings suggest that EGCG-Zn NPs alleviate DSS-induced colitis by mitigating inflammation, suppressing oxidative stress, and promoting epithelial barrier repair, supporting their potential as a functional nutraceutical for UC management.

Fish oil (FO) has been shown to confer beneficial effects on hepatic diseases in both humans and animals. This study aimed to investigate whether dietary fish oil (FO) supplementation alleviates deoxynivalenol (DON)-induced liver injury by modulating the ferroptosis signaling pathway in weaned piglets. Twenty-four weaned piglets were allocated to a 2 × 2 factorial design, with the main factors consisting of dietary treatment (5% corn oil or 5% FO supplementation) and DON exposure (basal diet or diet contaminated with 4 mg/kg DON). After 21 days of dietary treatment, piglets were euthanized for collection of blood and liver samples. Dietary FO significantly attenuated DON-induced hepatic structural damage and inflammatory infiltration. Specifically, FO supplementation reduced the activities of aspartate transaminase (AST) and alkaline phosphatase (ALP), as well as the AST/alanine aminotransferase (ALT) ratio following DON exposure. Dietary FO also decreased malondialdehyde (MDA) concentrations in both the liver and serum, lowered hepatic 4-hydroxynonenal (4-HNE) level and Fe²⁺ content, and increased hepatic glutathione (GSH) content. Moreover, dietary FO ameliorated ultrastructural liver damage induced by DON. Furthermore, DON significantly downregulated the mRNA levels of multiple genes associated with iron metabolism and ferroptosis, including heat shock protein beta-1 (HSPB1), acyl-CoA synthetase long chain family member 4 (ACSL4), and arachidonate 15-lipoxygenase (ALOX15), and upregulated the mRNA levels of transferrin (TF), ferritin heavy chain (FTH), solute carrier family 7 member 11 (SLC7A11), and transferrin receptor 1 (TFR1). Dietary FO counteracted these alterations by decreasing the mRNA of SLC7A11, TFR1, FTH, and TF after DON exposure. Finally, FO significantly decreased the protein expression of SLC7A11, iron-responsive element-binding protein 2 (IREB2), and FHT1 and increased the GPX4 protein expression following DON exposure. These findings suggest that FO may ameliorate DON-induced liver injury in weaned piglets, possibly through suppressing the ferroptosis signaling pathway.

Zinc (Zn) imbalance—deficiency or overload—is implicated in hepatocyte injury, yet its mechanisms and therapeutic strategies remain incompletely understood. This study investigated Zn dyshomeostasis-induced hepatotoxicity in AML12 hepatocytes and evaluated fisetin’s protective potential in diet-induced Zn overload C57BL/6 mice for in vivo validation. In AML12 cells, both Zn deficiency and overload impaired hepatocyte viability and promoted oxidative stress, but only overload activated autophagy and the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Fisetin, a natural flavonoid with well-documented antioxidant and anti-inflammatory properties, selectively mitigated Zn overload-induced AML12 cytotoxicity and oxidative damage by enhancing autophagic flux and Nrf2 signaling without Zn chelation, while demonstrating no effect on Zn deficiency. Specifically, fisetin required autophagy to sustain Nrf2 activation, as chloroquine abolished its protective effects. In vivo, fisetin administration (200 mg/kg BW, oral gavage) alleviated Zn overload-associated weight loss and hepatic oxidative damage in mice, paralleling its in vitro effects through reinforced autophagy–Nrf2 axis activation. The autophagy-dependent Nrf2 activation mechanism highlights fisetin’s therapeutic potential for Zn-related liver disorders.

Quercetin (Que) is a flavonol compound found in plants, which has a variety of biological activities. Necroptosis, a special form of programmed cell death, plays a vital role in the development of many gastrointestinal diseases. This study aimed to explore whether Que could attenuate the intestinal injury and barrier dysfunction of piglets after deoxynivalenol (DON) exposure through modulating the necroptosis signaling pathway. Firstly, twenty-four weaned piglets were used in a 2 × 2 factorial design and the main factors, including Que (basal diet or diet supplemented with 100 mg/kg Que) and DON exposure (control feed or feed contaminated with 4 mg/kg DON). After feeding for 21 d, piglets were killed for samples. Next, the intestinal porcine epithelial cell line (IPEC-1) was pretreated with or without Que (10 μmol/mL) in the presence or absence of a DON challenge (0.5 μg/mL). Dietary Que increased the body weight, average daily gain, and average daily feed intake (p < 0.05) through the trial. Que supplementation improved the villus height, and enhanced the intestinal barrier function (p < 0.05) indicated by the higher protein expression of occludin and claudin-1 (p < 0.05) in the jejunum of the weaned piglets after DON exposure. Dietary Que also down-regulated the protein abundance of total receptor interacting protein kinase 1 (t-RIP1), phosphorylated RIP1 (p-RIP1), p-RIP3, total mixed lineage kinase domain-like protein (t-MLKL), and p-MLKL (p < 0.05) in piglets after DON exposure. Moreover, Que pretreatment increased the cell viability and decreased the lactate dehydrogenase (LDH) activity (p < 0.05) in the supernatant of IPEC-1 cells after DON challenge. Que treatment also improved the epithelial barrier function indicated by a higher transepithelial electrical resistance (TEER) (p < 0.001), lower fluorescein isothiocyanate-labeled dextran (FD4) flux (p < 0.001), and better distribution of occludin and claudin-1 (p < 0.05) after DON challenge. Additionally, pretreatment with Que also inhibited the protein abundance of t-RIP1, p-RIP1, t-RIP3, p-RIP3, t-MLKL, and p-MLKL (p < 0.05) in IPEC-1 cells after DON challenge. In general, our data suggest that Que can ameliorate DON-induced intestinal injury and barrier dysfunction associated with suppressing the necroptosis signaling pathway.