Search

Diacylglycerol acyltransferase 2 (DGAT2) catalyzes the final step of triglyceride (TG) synthesis. DGAT2 deletion in mice lowers liver TGs, and DGAT2 inhibitors are under investigation for the treatment of fatty liver disease. Here, we show that DGAT2 inhibition also suppressed SREBP-1 cleavage, reduced fatty acid synthesis, and lowered TG accumulation and secretion from liver. DGAT2 inhibition increased phosphatidylethanolamine (PE) levels in the endoplasmic reticulum (ER) and inhibited SREBP-1 cleavage, while DGAT2 overexpression lowered ER PE concentrations and increased SREBP-1 cleavage in vivo. ER enrichment with PE blocked SREBP-1 cleavage independent of Insigs, which are ER proteins that normally retain SREBPs in the ER. Thus, inhibition of DGAT2 shunted diacylglycerol into phospholipid synthesis, increasing the PE content of the ER, resulting in reduced SREBP-1 cleavage and less hepatic steatosis. This study reveals a new mechanism that regulates SREBP-1 activation and lipogenesis that is independent of sterols and SREBP-2 in liver. [Display omitted] • Inhibition of DGAT2 in hepatocytes shunts DAGs to phospholipid synthesis • Inhibition of DGAT2 in hepatocytes increased PE concentrations in the ER • Increased PE concentrations in the ER block SREBP-1 cleavage, reducing lipogenesis DGAT2 inhibition blocks triglyceride synthesis in liver and is a promising new approach for the treatment of steatotic liver diseases. Rong et al. show that DGAT2 inhibition has a dual effect: it not only blocks the last step of triglyceride synthesis but also suppresses SREBP-1, the transcriptional activator of lipogenesis in liver. [ABSTRACT FROM AUTHOR]

Abstract: Background: Nonalcoholic fatty liver disease is closely associated with metabolic syndrome and cardiovascular disease (CVD). We investigated whether the liver fat content (LFC) is independently associated with carotid artery intima-media thickness (CIMT) and evaluated the contribution of the LFC to the increased CIMT. Methods: We conducted a community-based study among 1809 participants (682 males and 1127 females) from the Changfeng Study who were at least 45 years old. A standard interview, anthropometrics and laboratory parameters were performed for each participant. The CIMT was determined by ultrasonography. A large CIMT value was defined as 75th percentile of the maximum CIMT. A standardised ultrasonographic hepatic-renal ratio was used to assess the LFC. Results: The median LFC value was 6% (interquartile range, 3–14%), and 34% of the subjects had hepatic steatosis based on the criteria for diagnosis of steatosis by quantitative ultrasound. The maximum CIMT, average CIMT and plaque score were strongly associated with the LFC (β = 0.319, 0.324 and 1.361, respectively; all P < 0.05) after adjustment for age, gender, smoking history, low-density lipoprotein cholesterol and metabolic syndrome. The multiple logistic regression analysis showed that a 1 SD increase in the LFC, the OR for having a large CIMT was 1.350 (95% CI 1.180–1.545; P < 0.001) after adjustment for all potential confounders. Conclusions: These results suggest that the LFC is independently associated with carotid atherosclerosis in the Chinese population, and that the risk of atherosclerosis is proportional to the degree of hepatic steatosis. [Copyright &y& Elsevier]

Nonalcoholic steatohepatitis (NASH) is an advanced stage of nonalcoholic fatty liver disease (NAFLD) with serious consequences that currently lacks approved pharmacological therapies. Recent studies suggest the close relationship between the pathogenesis of NAFLD and the dysregulation of RNA splicing machinery. Here, we reveal death-associated protein kinase-related apoptosis-inducing kinase-2 (DRAK2) is markedly upregulated in the livers of both NAFLD/NASH patients and NAFLD/NASH diet-fed mice. Hepatic deletion of DRAK2 suppresses the progression of hepatic steatosis to NASH. Comprehensive analyses of the phosphoproteome and transcriptome indicated a crucial role of DRAK2 in RNA splicing and identified the splicing factor SRSF6 as a direct binding protein of DRAK2. Further studies demonstrated that binding to DRAK2 inhibits SRSF6 phosphorylation by the SRSF kinase SRPK1 and regulates alternative splicing of mitochondrial function-related genes. In conclusion, our findings reveal an indispensable role of DRAK2 in NAFLD/NASH and offer a potential therapeutic target for this disease. [Display omitted] • DRAK2 is markedly upregulated in the livers of both patients and mice with NAFLD/NASH • DRAK2 regulates RNA alternative splicing through SRPK1-mediated SRSF6 phosphorylation • DRAK2 disturbs mitochondrial function in hepatic steatosis via RNA splicing machinery • Suppression of DRAK2 in hepatocytes ameliorates NAFLD/NASH progression Li et al. identified DRAK2 as a novel and essential regulator of nonalcoholic steatohepatitis (NASH). DRAK2 promotes NASH via directly interacting with SRSF6 to inhibit its phosphorylation by SRPK1 and regulate alternative splicing of mitochondrial function-related genes. This functional mechanism of DRAK2 offers a potential therapeutic target for this disease. [ABSTRACT FROM AUTHOR]

• A new two-step crosslinked PVA/alginate/MMT aerogel shows high flame retardancy. • The crosslinked PVA/alginate/MMT aerogel exhibits ultra-low-smoke-toxicity. • The compression property of the crosslinked PVA/alginate/MMT aerogel enhanced. A highly efficient flame-retardant and ultra-low-smoke-toxicity biodegradable material, poly(vinyl alcohol) (PVA)/alginate/montmorillonite (MMT) composite aerogel, was fabricated by a new environment-friendly two-step crosslinking strategy using borate and calcium ions. Compressive and specific moduli of the crosslinked PVA/alginate/MMT (P4A4M4/BA/Ca) aerogel increased to 7.2- and 1.9-folds those of the non-crosslinked aerogel, respectively, and the limited oxygen index value increased to 40.0%. Cone calorimeter tests revealed that the total heat release and peak heat release rate values of the P4A4M4/BA/Ca composite aerogel distinctly decreased. Remarkably, the total smoke release value of the P4A4M4/BA/Ca aerogel was considerably lower than those of non-crosslinked PVA composite aerogels, indicating its superior smoke suppression ability and high fire hazardous safety. The flame-retardancy mechanism of the crosslinked P4A4M4/BA/Ca composite aerogels involved a combination of the gaseous phase and condensed phase flame retardancy. The high-performance PVA/alginate/MMT biodegradable composite aerogels with good sustainability is a promising alternative to conventional flame-retardant foams. [ABSTRACT FROM AUTHOR]

Berberine (BBR), a natural compound extracted from Chinese herb, has been shown to effectively attenuate nonalcoholic fatty liver disease (NAFLD) in clinic. However, the mechanism underlying the effect of BBR is not fully understood. Stearyl-coenzyme A desaturase 1 (SCD1) mediates lipid metabolism in liver. Therefore, we hypothesized that SCD1 mediated the beneficial effect of BBR on NAFLD. The expression of SCD1 was measured in the liver of NAFLD patients and ob/ob mice. The effect of BBR on NAFLD was evaluated in C57BL/6 J mice on high fat diet (HFD). The effect of BBR was also investigated in HepG2 and AML12 cells exposed to high glucose and palmitic acid. Oil red O staining was performed to detect triglyceride (TG) level. Quantitative real-time polymerase chain reaction and Western blot were used to detect the messenger ribonucleic acid (mRNA) and protein expression of target genes. The activity of SCD1 promoter was measured by dual-luciferase reporter assay. The expression of SCD1 was increased in the liver of NAFLD patients and ob/ob mice. BBR reduced hepatic TG accumulation and decreased the expressions of hepatic SCD1 and other TG synthesis related genes both in vivo and in vitro. Knockdown of SCD1 expression mimicked the effect of BBR decreasing TG level in steatotic hepatocytes, whereas overexpression of SCD1 attenuated the effect of BBR. Mechanistically, BBR promoted the phosphorylation of AMP-activated protein kinase (AMPK) and sterol regulatory element-binding protein-1c (SREBP-1c) in HepG2 cells and the liver of HFD-fed mice. Activation of the AMPK-SREBP-1c pathway and sterol regulatory element (SRE) motif in SCD1 promoter (−920/-550) was responsible for the BBR-induced suppression of SCD1. BBR reduces liver TG synthesis and attenuates hepatic steatosis through the activation of AMPK-SREBP-1c-SCD1 pathway. Image 1 • The expression of SCD1 is increased in the liver of NAFLD patients and mice with fatty liver compared with control group. • Berberine reduces the expression of SCD1 in the liver and attenuates hepatic steatosis. • AMPK-SREBP-1c-SCD1 pathway mediates the effect of berberine on hepatic steatosis. • This study identifies a novel mechanism for berberine in the treatment of steatosis, which may promote its application. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A highly-efficient flame retardant PPDA in PLA shows good melt-dripping resistance. • The flame retarded PLA material with only 3 wt% PPDA passes UL-94 V-0 rating. • A small amount of PPDA has little influence on the mechanical properties of PLA. Abstract Flame-retarded poly(lactic acid) (PLA) biodegradable materials are viewed as promising as sustainable alternatives to petroleum-based commodity polymers. A new highly efficient flame retardant, poly(phenylphosphoryl phenylenediamine) (PPDA), was synthesized by the condensation of phenylphosphoryl dichloride with p -phenylenediamine and its structure was confirmed by 1H nulear magnetic resonance and Fourier-transform infrared spectroscopy. When 3 wt% PPDA was incorporated into PLA, the limited oxygen index increased from 20.0% of neat PLA to 25.5% and its UL-94 vertical burning testing achieved V-0 rating. Moreover, the total heat release and peak heat release rate values of PLA/3 wt% PPDA material were decreased from 109.1 MJ/m2 and 643.7 kW/m2 of PLA to 98.3 MJ/m2 and 570.0 kW/m2, respectively, and the fire performance index increased from 0.081 of PLA to 0.132 m2 s/kW. The high fire safety of PPDA in PLA is mainly attributed to the combined effects of the phosphorous-containing radical inhibition and inert gases and the barrier action of the formed char layer. The addition of less than 3 wt% PPDA has little influence on the tensile and impact properties of PLA. The flame retardant PLA blends have great application potential in electrical casing, automobile interiors and three-dimensional printing materials. [ABSTRACT FROM AUTHOR]

Vascular inflammation is a common pathological basis underlying many cardiovascular diseases. As such, the treatment of vascular inflammation has attracted increasing attention. The Piezo1 pathway has long been shown to play an important role in the development of vascular inflammation. Jatrorrhizine (Jat) is an effective component of Rhizoma Coptidis. It is commonly used in the treatment of inflammatory diseases and is a potential drug for the treatment of vascular inflammation. However, its mechanism of action on vascular inflammation remains unclear, as is the effect of Jat on Piezo1. Therefore, we conducted a series of studies on the effect of jatrorrhizine on vascular inflammation in vivo and in vitro. In this study, the effect of Jat treatment on H 2 O 2 -induced endothelial cell inflammation was investigated in vitro, and the potential mechanism of Jat was explored. In in vivo experiments, we investigated the effect of jatrorrhizine on vascular inflammation induced by carotid artery ligation and its effect on the Piezo1 signaling pathway. We found that Jat could reduce the severity of carotid intimal hyperplasia and local vascular inflammation in mice. In the H 2 O 2 -induced inflammation model, cell proliferation and migration were significantly inhibited, and the expression of pro-inflammatory factors was reduced. Importantly, the addition of Jat to endothelial Piezo1 knockout did not produce further significant inhibition. We believe that the role of Jat in the treatment of vascular inflammation may be related to Piezo1. And we believe that Jat has great potential in the treatment of vascular inflammation and cardiovascular diseases. [Display omitted] • Chinese medicine monomer jatrorrhizine has the effect of treating vascular inflammation. • The absence of mechanically sensitive ion channel Piezo1 protein can inhibit the development of vascular inflammation. • Jatrorrhizine can inhibit the opening of piezo1 channel induced by Yoda1. • Jatrorrhizine exerts anti-vascular inflammation by regulating the opening of piezo1 ion channel. [ABSTRACT FROM AUTHOR]