LZP is required for hepatic triacylglycerol transportation through maintaining apolipoprotein B stability.

The conserved zona pellucida (ZP) domain is found in hundreds of extracellular proteins that are expressed in various organs and play a variety of roles as structural components, receptors and tumor suppressors. A liver-specific zona pellucida domain-containing protein (LZP), also named OIT3, has been shown to be mainly expressed in human and mouse hepatocytes; however, the physiological function of LZP in the liver remains unclear. Here, we show that Lzp deletion inhibited very low-density lipoprotein (VLDL) secretion, leading to hepatic TG accumulation and lower serum TG levels in mice. The apolipoprotein B (apoB) levels were significantly decreased in the liver, serum, and VLDL particles of LZP-deficient mice. In the presence of LZP, which is localized to the endoplasmic reticulum (ER) and Golgi apparatus, the ER-associated degradation (ERAD) of apoB was attenuated; in contrast, in the absence of LZP, apoB was ubiquitinated by AMFR, a known E3 ubiquitin ligase specific for apoB, and was subsequently degraded, leading to lower hepatic apoB levels and inhibited VLDL secretion. Interestingly, hepatic LZP levels were elevated in mice challenged with a high-fat diet and humans with simple hepatic steatosis, suggesting that LZP contributes to the physiological regulation of hepatic TG homeostasis. In general, our data establish an essential role for LZP in hepatic TG transportation and VLDL secretion by preventing the AMFR-mediated ubiquitination and degradation of apoB and therefore provide insight into the molecular function of LZP in hepatic lipid metabolism.

Application of qPCR assays based on haloacids transporter gene dehp2 for discrimination of Burkholderia and Paraburkholderia.

BACKGROUND: A major facilitator superfamily transporter Dehp2 was recently shown to be playing an important role in transport and biodegradation of haloacids in Paraburkholderia caribensis MBA4, and Dehp2 is phylogenetically conserved in Burkholderia sensu lato. RESULTS: We designed both Burkholderia sensu stricto-specific and Paraburkholderia-specific qPCR assays based on dehp2 and 16S rRNA, and validated the qPCR assays in 12 bacterial strains. The qPCR assays could detect single species of Burkholderia sensu stricto or Paraburkholderia with high sensitivity and discriminate them in mixtures with high specificity over a wide dynamic range of relative concentrations. At relatively lower cost compared with sequencing-based approach, the qPCR assays will facilitate discrimination of Burkholderia sensu stricto and Paraburkholderia in a large number of samples. CONCLUSIONS: For the first time, we report the utilization of a haloacids transporter gene for discriminative purpose in Burkholderia sensu lato. This enables not only quick decision on proper handling of putative pathogenic samples in Burkholderia sensu stricto group but also future exploitation of relevant species in Paraburkholderia group for haloacids biodegradation purposes.

Quzhi Formula Alleviates Nonalcoholic Steatohepatitis by Impairing Hepatocyte Lipid Accumulation and Inflammation via Bip/eIF2α Signaling.

Background and Aims: The Quzhi formula, a Chinese medicine compound prescription, relieves nonalcoholic steatohepatitis (NASH) symptoms. This study aimed to explore the mechanism of the Quzhi formula against NASH. Methods: A choline-deficient, L-amino acid-defined, high-fat diet induced a NASH mouse model and a free fatty acid-induced mouse hepatocyte cell model were used to evaluate the function of Quzhi formula in vivo and in vitro. Network pharmacology and molecular docking technology were performed to uncover the possible protective mechanisms of the Quzhi formula against NASH. Key factors in liver lipid metabolism and endoplasmic reticulum (ER) stress pathway were evaluated to verify the mechanism. Results: The positive contribution of the Quzhi formula on NASH was confirmed in vivo and in vitro. Abnormal accumulation of lipid in the liver and inflammatory responses were significantly decreased by the Quzhi formula. Network pharmacological analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the Quzhi formula protected against NASH by regulating ER stress and inflammatory responses, which was enhanced by further molecular docking analysis. In addition, mechanism exploration showed that Quzhi formula mainly reduced ER stress by downregulating Bip/eIF2α signaling. Conclusions: The Quzhi formula protected against NASH by inhibiting lipid accumulation, ER stress, and inflammatory responses, which supports the potential use of Quzhi formula as an alternative treatment for NASH.

Clonal evolution in liver cancer at single-cell and single-variant resolution.

Genetic heterogeneity of tumor is closely related to its clonal evolution, phenotypic diversity and treatment resistance, and such heterogeneity has only been characterized at single-cell sub-chromosomal scale in liver cancer. Here we reconstructed the single-variant resolution clonal evolution in human liver cancer based on single-cell mutational profiles. The results indicated that key genetic events occurred early during tumorigenesis, and an early metastasis followed by independent evolution was observed in primary liver tumor and intrahepatic metastatic portal vein tumor thrombus. By parallel single-cell RNA-Seq, the transcriptomic phenotype of HCC was found to be related with genetic heterogeneity. For the first time we reconstructed the single-cell and single-variant clonal evolution in human liver cancer, and dissection of both genetic and phenotypic heterogeneity will facilitate better understanding of their relationship.

Arid1a regulates insulin sensitivity and lipid metabolism.

BACKGROUND: Although significant progress has been made in understanding the mechanisms of steatosis and insulin resistance, the physiological functions of the epigenetic regulators in these processes remain largely elusive. METHODS: Hepatocyte-specific Arid1a knockout mice were administrated with high-fat diet (HFD) for 12 weeks, then insulin sensitivity was assessed by glucose tolerance test (GTT) and insulin tolerance test (ITT). The metabolism-related indicators were determined by employing a variety of biological methods, including histology, real-time PCR, enzyme-linked immunosorbent assay (ELISA), Western blotting assay, Chromatin immunoprecipitation (ChIP), RNA-seq and assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq). FINDINGS: Hepatocyte-specific Arid1a deletion significantly increases susceptibility to develop hepatic steatosis, insulin resistance and inflammation in mice fed a HFD. In vitro, Arid1a deletion in isolated hepatocytes directly leads to free fatty acid-induced lipid accumulation and insulin resistance. Mechanically, Arid1a deficiency impairs fatty acid oxidation by downregulating PPARα and altering the epigenetic landscape of some metabolism genes. INTERPRETATION: These findings reveal that targeting Arid1a might be a promising therapeutic strategy for liver steatosis and insulin resistance. FUND: This work was supported by National Natural Science Foundation of China (81672772 and 81472621), China National Science and Technology Major Project for Prevention and Treatment of Infectious Diseases (No.2017ZX 10203207) and National Program on Key Research Project of China (grant no. 2016YFC0902701).