Regulation Of Lipase Activity Research Articles

Quantitative analysis of lipid metabolism-related differential proteins in patients with alcoholic liver disease

Objective: To screen and identify differential proteins, analyze lipid metabolism-related proteins and pathways, and explore their functions and biological processes in liver tissue of patients with alcoholic liver disease using tandem mass tag (TMT) labeling technology. Methods: Liver tissues that met the inclusion criteria were collected. Eight samples from patients with alcoholic cirrhosis and three samples from the normal control group were screened out. The TMT technique was used to screen differential proteins, perform signaling pathway enrichment analysis, and analyze protein interaction networks to explore the biological processes involved in them. Results: Proteomic analysis identified 2 741 kinds of differentially expressed proteins in the two groups of data with statistical significance (P < 0.05). The standard criteria of P < 0.05 and |log2(foldchange)| > 1 had screened out 106 kinds of differentially expressed proteins. Compared with the control group, the alcoholic liver disease group had 12 kinds of up-regulated proteins and 94 kinds of down-regulated proteins. Among them, there were 2 kinds of up-regulated differential proteins related to lipid metabolism and 14 kinds of down-regulated differential proteins. The results of bioinformatics analysis showed that these proteins were primarily involved in biological processes such as lipid transport, regulation of lipase activity, fatty acid binding, and cholesterol metabolism in lipid metabolism and also had a close link to signal pathways related to lipid metabolism such as peroxisome proliferator-activated receptor signaling pathways, cholesterol metabolism, triglyceride metabolism, and regulation of lipolysis in adipocytes. Conclusion: The 16 kinds of lipid metabolism-related differential proteins may be the key proteins in the pathogenesis of alcoholic liver disease.

Identifying the Potential Roles of PBX4 in Human Cancers Based on Integrative Analysis.

PBX4 belongs to the pre-B-cell leukemia homeobox (PBX) transcription factors family and acts as a transcriptional cofactor of HOX proteins participating in several pathophysiological processes. Recent studies have revealed that the dysregulation of PBX4 is closely related to multiple diseases, especially cancers. However, the research on PBX4’s potential roles in 33 cancers from the Cancer Genome Atlas (TCGA) is still insufficient. Therefore, we performed a comprehensive pan-cancer analysis to explore the roles of PBX4with multiple public databases. Our results showed that PBX4 was differentially expressed in 17 types of human cancer and significantly correlated to the pathological stage, tumor grade, and immune and molecular subtypes. We used the Kaplan–Meier plotter and PrognoScan databases to find the significant associations between PBX4 expression and prognostic values of multiple cancers. It was also found that PBX4 expression was statistically related to mutation status, DNA methylation, immune infiltration, drug sensitivity, and immune checkpoint blockade (ICB) therapy. Additionally, we found that PBX4 was involved in different functional states of multiple cancers from the single-cell resolution perspective. Enrichment analysis results showed that PBX4-related genes were enriched in the cell cycle process, MAPK cascade, ncRNA metabolic process, positive regulation of GTPase activity, and regulation of lipase activity and mainly participated in the pathways of cholesterol metabolism, base excision repair, herpes simplex virus 1 infection, transcriptional misregulation in cancer, and Epstein–Barr virus infection. Altogether, our integrative analysis could help in better understanding the potential roles of PBX4 in different human cancers.

Identification of the anti-tumor activity and mechanisms of nuciferine through a network pharmacology approach.

Nuciferine is an aporphine alkaloid extracted from lotus leaves, which is a raw material in Chinese medicinal herb for weight loss. In this study we used a network pharmacology approach to identify the anti-tumor activity of nuciferine and the underlying mechanisms. The pharmacological activities and mechanisms of nuciferine were identified through target profile prediction, clustering analysis and functional enrichment analysis using our traditional Chinese medicine (TCM) network pharmacology platform. The anti-tumor activity of nuciferine was validated by in vitro and in vivo experiments. The anti-tumor mechanisms of nuciferine were predicted through network target analysis and verified by in vitro experiments. The nuciferine target profile was enriched with signaling pathways and biological functions, including "regulation of lipase activity", "response to nicotine" and "regulation of cell proliferation". Target profile clustering results suggested that nuciferine to exert anti-tumor effect. In experimental validation, nuciferine (0.8 mg/mL) markedly inhibited the viability of human neuroblastoma SY5Y cells and mouse colorectal cancer CT26 cells in vitro, and nuciferine (0.05 mg/mL) significantly suppressed the invasion of 6 cancer cell lines in vitro. Intraperitoneal injection of nuciferine (9.5 mg/mL, ip, 3 times a week for 3 weeks) significantly decreased the weight of SY5Y and CT26 tumor xenografts in nude mice. Network target analysis and experimental validation in SY5Y and CT26 cells showed that the anti-tumor effect of nuciferine was mediated through inhibiting the PI3K-AKT signaling pathway and IL-1 levels in SY5Y and CT26 cells. By using a TCM network pharmacology method, nuciferine is identified as an anti-tumor agent against human neuroblastoma and mouse colorectal cancer in vitro and in vivo, through inhibiting the PI3K-AKT signaling pathways and IL-1 levels.

Differentially expressed genes identified by microarray analysis following oxymatrine treatment of hepatic stellate cell

AIM: To investigate the effects of oxymatrine on the gene expression profile of hepatic stellate cell (HSC) and provide novel insights into the mechanism of oxymatrine against hepatic fibrosis. Methods: HSC was isolated from normal SD by in situ perfusion of collagenase and pronase and density Nycodenz gradient centrifugation. MTT colorimetry was used to study the effect of oxymatrine on the proliferation of HSC. Total RNA and mRNA of quiescent HSC, culture-activated HSC and oxymatrine treated HSC were extracted. Effect of oxymatrine on HSC gene expression profile was detected by oligonucleotide microarray analysis with Affymetrix gene chip rat U230A. Differentially expressed genes were annotated with Gene Ontology (GO) and analyzed with Kyoto encyclopedia of genes and genomes (KEGG) pathway using the Database for Annotation, Visualization and Integrated Discovery. Results: Oxymatrine could inhibit the proliferation of HSC in a dose-dependent manner. A total of 4641 differentially expressed genes were identified by cDNA chip between activated and quiescent HSC, among which 2702 genes were upregulated, and 1939 genes were down-regulated in activated HSC. cDNA microarray uncovered downregulation of 56 genes in response to oxymatrine, the representative genes including alpha 2 type I procollagen, alpha-1 type I collagen, tissue inhibitor of metalloproteinase 1, interleukin 1 beta, early growth response 1, chemokine ligand 2, chemokine ligand 1, CTGF, TGFβ1. The most enriched GO terms included response to wounding, inflammatory response, cell migration, cell motility, wound healing, TGFβ receptor signaling pathway. KEGG pathway analysis revealed that oxymatrine affected the ECM-receptor interaction, focal adhesion, cytokine-cytokine recaptor interaction, TGFβ signaling pathway, MAPK signaling pathway. There were 37 genes upregulated significantly following oxymatrine treatment. The most enriched GO terms included oxidation reduction, negative regulation of lipoprotein oxidation, regulation of lipoprotein oxidation, steroid metabolic process, regulation of lipase activity. Six genes were confirmed with QPCR, consistent with microarray. Conclusion: The mechanism of oxymatrine in inhibiting liver fibrogenesis is associated with multi-genes and multi-pathways regulation.

Structural and Functional Studies of Casein Kinase I-Like Protein from Rice

Casein kinase I (CKI) is a protein serine/threonine kinase that is highly conserved from plants to animals. It performs various functions in both the cytoplasm and nucleus, such as DNA repair, cell cycle, cytokinesis, vesicular trafficking, morphogenesis and circadian rhythm. CKI proteins contain a highly conserved kinase domain responsible for catalytic activity at the N-terminus and a highly diverse regulatory domain responsible for determining substrate specificity at the C-terminus. CKI-like protein has been identified in plants, including in rice, but its function and structure have not been reported. Here, we report the 2.0 Å crystal structure of the kinase domain of CKI-like protein from rice. Although the structure adopts the typical bi-lobal kinase architecture, the length and orientation of the glycine-rich ATP-binding motif are dynamic within the CKI family. A loop between α5 and α6 (the α5-α6 loop), which was previously not detected in the CKI family because of flexibility, was clearly detected in our structure. In addition, we identified a lipase as a substrate of CKI-like protein from rice. Phosphorylation of the lipase dramatically reduced its catalytic activity, suggesting that CKI may play a role in the regulation of lipase activity.

Production and Regulation of Lipase Activity from Penicillium restrictum in Submerged and Solid-State Fermentations

Different carbon (C) sources, mainly carbohydrates and lipids, have been screened for their capacity to support growth and lipase production by Penicillium restrictum in submerged fermentation (SmF) and in solid-state fermentation (SSF). Completely different physiological behaviors were observed after the addition of easily (oleic acid and glucose) and complex (olive oil and starch) assimilable C sources to the liquid and solid media. Maximal lipolytic activities (12.1 U/mL and 17.4 U/g) by P. restrictum were obtained with olive oil in SmF and in SSF, respectively. Biomass levels in SmF (12.2-14.1 mg/mL) and SSF (7.0-8.0 mg/g) did not varied greatly with the distinct C sources used. High lipase production (12.3 U/g) using glucose was only attained in SSF, perhaps due to the ability of this fermentation process to minimize catabolite repression.

Regulation of lipase activities in rat brain in vitro.

Regulation of acid and neutral lipase activities in rat brain was examined in vitro. Both activities were decreased by SDS, CuCl2 and ZnCl2 and by delipidation. The neutral lipase activity was also markedly reduced by N-ethylmaleimide and PbCl2. The activity of delipidated preparation was increased by addition of phosphatidyl choline at both pH 5.5 and 7.5 and by phosphatidyl serine at acidic pH value. Pretreatments of the enzyme preparation with phospholipase A and trypsin reduced the lipase activities at both pH values. It is suggested that phospholipids play an important role on lipase activity in brain.

Properties of a membrane-bound triglyceride lipase of rapeseed (Brassica napus L.) cotyledons

The properties of the alkaline lipase activity (EC 3.1.1.3) that was recovered almost completely from a microsomal membrane fraction of 4-d-old rapeseed (Brassica napus L.) cotyledons were studied employing a titrimetric test procedure. The apparent KM was 6.5 mmol l(-1), with emulgated sunflower oil as the substrate. The products of triglyceride hydrolysis in vitro were glycerol, free fatty acids, and minor amounts of mono- and diglycerides. Maximum lipase activity depended on the preincubation of the lipolytic membrane fraction in 0.15 mol l(-1) NaCl and on the presence of at least 0.1 mol l(-1) NaCl in the test mixture. Desoxycholate and up to 0.1 mol l(-1) CaCl2 also activated the enzyme while EDTA and detergents such as trito x-100, digitonin, tween 85, and sodium dodecylsulfate were inhibitory. The rapeseed lipase displayed a conspicuous substrate selectivity among different plant triglycerides; the activity was inversely correlated with the oleic acid content of the oils. Water-soluble triacetin and the phospholipid lecithin were not hydrolyzed. Increasing amounts of free fatty acids reduced lipase activity; erucic acid, a major component of rapeseed oil, exhibited the strongest effect, suggesting a possible role in the regulation of lipase activity in vivo. The data demonstrate that the lipolytic membrane fraction houses a triglyceride lipase with properties similar to other plant and animal lipases. It can both qualitatively and quantitatively account for the fat degradation in rapeseed cotyledons. The evidence that provides further reason to acknowledge the membranous appendices of the spherosomes as the intracellular site of lipolysis is discussed.