Loss of LBP triggers lipid metabolic disorder through H3K27 acetylation-mediated C/EBPß- SCD activation in non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is associated with mutations in lipopolysaccharide-binding protein ( LBP), but the underlying epigenetic mechanisms remain understudied. Herein, LBP -/- rats with NAFLD were established and used to conduct integrative targeting-active enhancer histone H3 lysine 27 acetylation (H3K27ac) chromatin immunoprecipitation coupled with high-throughput and transcriptomic sequencing analysis to explore the potential epigenetic pathomechanisms of active enhancers of NAFLD exacerbation upon LBP deficiency. Notably, LBP -/- reduced the inflammatory response but markedly aggravated high-fat diet (HFD)-induced NAFLD in rats, with pronounced alterations in the histone acetylome and regulatory transcriptome. In total, 1 128 differential enhancer-target genes significantly enriched in cholesterol and fatty acid metabolism were identified between wild-type (WT) and LBP -/- NAFLD rats. Based on integrative analysis, CCAAT/enhancer-binding protein ß (C/EBPß) was identified as a pivotal transcription factor (TF) and contributor to dysregulated histone acetylome H3K27ac, and the lipid metabolism gene SCD was identified as a downstream effector exacerbating NAFLD. This study not only broadens our understanding of the essential role of LBP in the pathogenesis of NAFLD from an epigenetics perspective but also identifies key TF C/EBPß and functional gene SCD as potential regulators and therapeutic targets.

[Extracts from Testudinis Carapacis et Plastri Regulates Expression of ID1 in Mscs].

OBJECTIVE: To explore BMP4 affecting the Extracts from Testudinis Carapacis et Plastri (PTE) stimulating proliferation of MSCs and the mechanism. METHODS: Cotransfected PGL3-IDI and pEGFP-BMP4 of 0, 0. 1,0. 3, 0. 5 and 1 µg/mL respectively using the calcium phosphate co-precipitation method in rat MSCs. One of transfected cells were divided into control group and PTE group. PTE group was stimulated by PTE of 30 µ/L for 36 h, while control group was not. Collected cells using lucifease activity measurement to detect the activity of ID. Then 0. 3 µg/mL pEGFP-BMP4 was chose to cotransfect. MSCs was divided into control group, PTE group, BMP4 group, BMP4 + PTE group. BMP4 and BMP4 + PTE group were cotransfected with PGL3-ID1 and pEGFP-BMP4 but control or PTE groups were not. PTE and BMP4 + PTE groups were stimulated by PTE of 30 µg/mL for 36 h but the either two groups were not. The activities of ID1, BMP4 and RARα were detected using RT-PCR. RESULTS: The expressions of ID1, BMP4 and RARa rose in PTE group. The expression of BMP4 and RARα rose while IDI decreased in BMP4 groups. BMP4, ID1 and RARα decreased remarkable in BMP4 + PTE group comparing with BMP4 group. CONCLUSION: PTE promotes the proliferation of MSCs, it also regulates the expression of BMP4 to prevent excessive proliferation of MSCs.

Identification of a puromycin-sensitive aminopeptidase from zebrafish (Danio rerio).

An aminopeptidase from zebrafish (Danio rerio) was purified 1247-fold to homogeneity with 35.4% recovery by column chromatography successively on DEAE-sephacel, hydroxyapatite, and phenyl-sepharose. The molecular mass of the enzyme was estimated at 98 kDa by SDS-PAGE and gel filtration. Optimum temperature and pH of the enzyme were 45°C and 7.5, respectively. The enzyme preferentially hydrolyzed substrate Leu-MCA with k(cat)/K(m) of 4.2×10(6)M(-1)s(-1) and an activation energy of 68.9 kJ M(-1) [corrected], respectively. It was specifically inhibited by bestatin, puromycin and metal-chelating agents, and Zn(2+) seemed to be its metal cofactor(s). Some l-amino acids significantly inhibited its activity, and l-cysteine was a non-competitive inhibitor with a K(i) of 0.27 mM. According to the peptide mass fingerprint analysis, the enzyme was highly matched with the predicted D. rerio aminopeptidase puromycin sensitive (gi: 255683530) (EC 3.4.11.14), suggesting that the present enzyme is a puromycin-sensitive aminopeptidase of zebrafish.