Forsythia Fruit Prevents Fulminant Hepatitis in Mice and Ameliorates Inflammation in Murine Macrophages.

Forsythia Fruit (FF), the fruit of Forsythia suspensa, has been used since ancient times as an herbal medication in East Asia to treat inflammation, gonorrhea, and pharyngitis. However, the efficacy of FF against liver damage due to inflammation has not been studied. Here, we explored the protective effects of FF in a mouse hepatitis model induced by lipopolysaccharide (LPS)/D-galactosamine (GalN) treatment. We measured inflammatory cytokine and aminotransferase levels in mouse blood and analyzed the effects of FF on inflammatory gene and protein expression levels in liver tissue. Our results show that FF treatment effectively lowers inflammatory cytokine and serum aminotransferase levels in mice and inhibits the expression of hepatic cytokine mRNA and inflammatory proteins. Furthermore, treatment with FF activated the antioxidant pathway HO-1/Nrf-2 and suppressed severe histological alteration in the livers of LPS/D-GalN-treated mice. Further investigation of the effects of FF on inflammatory reactions in LPS-stimulated macrophages showed that pretreatment with FF inhibits inflammatory mediator secretion and activation of inflammatory mechanisms both in a mouse macrophage RAW 264.7 cells and in primary peritoneal macrophages. These results show that FF has potential worth as a candidate for the treatment of fulminant inflammatory reactions and subsequent liver injury.

The sirtuin 1 activator SRT1720 alleviated endotoxin-induced fulminant hepatitis in mice.

The metabolic sensor sirtuin 1 (SIRT1) also functions as a checkpoint in inflammation, and SRT1720 is a highly active and selective SIRT1 activator shown to alleviate inflammatory injury in several recent experimental studies. In the present study, the potential effects and underlying mechanisms of SRT1720 on lipopolysaccharide (LPS)-induced fulminant hepatitis in D-galactosamine (D-Gal)-sensitized mice were investigated. The results indicated that treatment with SRT1720 inhibited LPS/D-Gal-induced elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), alleviated the histological abnormalities, suppressed the induction of tumor necrosis factor alpha (TNF-α) and IL-6, mitigated the phosphorylation of c-Jun N-terminal kinase (JNK), downregulated the activities of caspase 8, caspase 9 and caspase 3, decreased the level of cleaved caspase 3, reduced the TUNEL-positive cells, and improved the survival rate of the LPS/D-Gal-exposed mice. These data indicated that treatment with the SIRT1 activator SRT1720 alleviated LPS/D-Gal-induced fulminant hepatitis, which might be attributed to the suppressive effects of SRT1720 on TNF-α production and the subsequent activation of the apoptosis cascade.

Withaferin A alleviates fulminant hepatitis by targeting macrophage and NLRP3.

Fulminant hepatitis (FH) is an incurable clinical syndrome where novel therapeutics are warranted. Withaferin A (WA), isolated from herb Withania Somnifera, is a hepatoprotective agent. Whether and how WA improves D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced FH is unknown. This study was to evaluate the hepatoprotective role and mechanism of WA in GalN/LPS-induced FH. To determine the preventive and therapeutic effects of WA, wild-type mice were dosed with WA 0.5 h before or 2 h after GalN treatment, followed by LPS 30 min later, and then killed 6 h after LPS treatment. To explore the mechanism of the protective effect, the macrophage scavenger clodronate, autophagy inhibitor 3-methyladenine, or gene knockout mouse lines NLR family pyrin domain containing 3 (Nlrp3)-null, nuclear factor-erythroid 2-related factor 2 (Nrf2)-null, liver-specific AMP-activated protein kinase (Ampk)a1 knockout (Ampka1ΔHep) and liver-specific inhibitor of KB kinase ß (Ikkb) knockout (IkkbΔHep) mice were subjected to GalN/LPS-induced FH. In wild-type mice, WA potently prevented GalN/LPS-induced FH and inhibited hepatic NLRP3 inflammasome activation, and upregulated NRF2 and autophagy signaling. Studies with Nrf2-null, Ampka1ΔHep, and IkkbΔHep mice demonstrated that the hepatoprotective effect was independent of NRF2, hepatic AMPKα1, and IκκB. Similarly, 3-methyladenine cotreatment failed to abolish the hepatoprotective effect of WA. The hepatoprotective effect of WA against GalN/LPS-induced FH was abolished after macrophage depletion, and partially reduced in Nlrp3-null mice. Consistently, WA alleviated LPS-induced inflammation partially dependent on the presence of NLRP3 in primary macrophage in vitro. Notably, WA potently and therapeutically attenuated GalN/LPS-induced hepatotoxicity. In conclusion, WA improves GalN/LPS-induced hepatotoxicity by targeting macrophage partially dependent on NLRP3 antagonism, while largely independent of NRF2 signaling, autophagy induction, and hepatic AMPKα1 and IκκB. These results support the concept of treating FH by pharmacologically targeting macrophage and suggest that WA has the potential to be repurposed for clinically treating FH as an immunoregulator.

Toll-like Receptor 4 Inhibitor TAK-242 Improves Fulminant Hepatitis by Regulating Accumulation of Myeloid-Derived Suppressor Cell.

Fulminant hepatitis (FH) is an acute clinical disease with a poor prognosis and high mortality rate. The purpose of this study was to determine the protective effect of the Toll-like receptor 4 (TLR4) inhibitor TAK-242 on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced explosive hepatitis and explore in vivo and in vitro mechanisms. Mice were pretreated with TAK-242 for 3 h prior to LPS (10 µg/kg)/D-GalN (250 mg/kg) administration. Compared to the LPS/D-GalN group, the TAK-242 pretreatment group showed significantly prolonged survival, reduced serum alanine aminotransferase and aspartate aminotransferase levels, relieved oxidative stress, and reduced inflammatory interleukin (IL)-6, IL-12, and tumor necrosis factor-α levels. In addition, TAK-242 increased the accumulation of myeloid-derived suppressor cells (MDSCs). Next, mice were treated with an anti-Gr-1 antibody to deplete MDSCs, and adoptive transfer experiments were performed. We found that TAK-242 protected against FH by regulating MDSCs. In the in vitro studies, TAK-242 regulated the accumulation of MDSCs and promoted the release of immunosuppressive inflammatory cytokines. In addition, TAK-242 inhibited protein expression of nuclear factor-κB and mitogen-activated protein kinases. In summary, TAK-242 had a hepatoprotective effect against LPS/D-GalN-induced explosive hepatitis in mice. Its protective effect may be involved in suppressing inflammation, reducing oxidative stress, and increasing the proportion of MDSCs.

Protective effect of diphenylmethyl selenocyanate against CCl4-induced hepatic injury.

Organoselenocyanates represent an important class of chemopreventive agent, which possess antioxidative, antimutagenic as well as cancer chemopreventive properties. The present study is an attempt to evaluate the protective effect of diphenylmethyl selenocyanate -- a synthetic organoselenocyanate against carbon tetrachloride (CCl(4))-induced hepatic damage in Swiss albino mice in vivo. Mice were pretreated with the Se-compound orally in a duration dependent manner (7 and 15 days) to observe its protective action against an acute toxic dose (24 h) of CCl(4) (single injection at a dose of 20 microl and 50 microl kg(-1) b.w.) that induced hepatic necrosis and caused DNA damage (strand breaks) in the hepatocytes. This study revealed that pretreatment with the Se-compound reduced the extent of massive hepatic necrosis in a duration dependent manner, but it had no modulatory effect on hepatocellular apoptosis caused by acute toxic doses of CCl(4). It was also found that the Se-compound could significantly (P < 0.01) prevent the CCl(4)-induced elevation of DNA damage in hepatocytes measured by comet assay in a duration dependent manner. So these findings will further strengthen the view that organoselenocyanate is an effective chemopreventive agent against acute hepatic damage, caused by halogenated alkanes such as CCl(4).