Upadrasta, S. | Search bioRxiv

bioRxiv2023

Functional characterization of five triterpene synthases through De-novo assembly and transcriptome analysis of Euphorbia grantii and Euphorbia tirucalli

Euphorbia grantii and Euphorbia tirucalli known to synthesize diverse triterpenes including euphol and tirucallol. These two triterpenes known to possess potent anti-cancer, anti-bacterial, and anti-fungal properties along with various other biological activities. In this study, De-novo assembly and comparative transcriptome analysis of leaf and stem tissues of E. tirucalli and E. grantii were carried out to identify thirteen triterpene synthases from 1,40,227 in correlation with the metabolic profiling. Comparative transcriptome analysis indicated that EutTTS4 and EutTTS5 genes which encodes for euphol/tirucallol and tirucallol synthase were highly expressed in leaf and stem tissue. The genes which encodes -amyrin synthase (EutTTS1) and lupeol synthase (EutTTS2) were characterized by overexpressing them in YPH499 yeast strain. We have developed using hem1 and erg7 knock yeast strain of lanosterol deficient yeast (TMBL17) and used for over expression of friedelin synthase (EutTTS3), and two novel triterpenes synthases such as euphol/tirucallol synthase (EutTTS4) and tirucallol synthase (EutTTS5). These results are very useful in large scale production of triterpenes by genomic integration of respective triterpene synthases in TMBL yeast strain developed in this study. Significance StatementWe have functionally characterized triterpene synthases from E. tirucalli and E. grantii and developed a hem1 and erg7 knock out of lanosterol deficient yeast (TMBL17) for the large-scale production of triterpene and triterpene related products.

molecular biology↗

bioRxiv2020

Chronic exposure to IL6 leads to deregulation of glycolysis and fat accumulation in the zebrafish liver

BACKGROUND AND AIMS Inflammation is a constant in Non-Alcoholic Fatty Liver Disease (NAFLD) and is usually considered a consequence. We propose that inflammation can be a cause for NAFLD. Obesity is strongly associated with (NAFLD), but not always. NAFLD in lean individuals is more common in certain populations, especially Asian-Indians. Lean healthy Indians also have a higher basal circulating IL6 suggesting a link with inflammation. We propose that inflammation-induced fatty liver could be relevant for studying obesity-independent NAFLD. Commonly used high-fat diet-induced NAFLD animal models are not ideal for testing this hypothesis.APPROACH AND RESULTS In this study we used a transgenic zebrafish with chronic systemic overexpression of human IL6 (IL6-OE) and found accumulation of triglyceride in the liver. We performed comparative transcriptomics and proteomics on the IL6-OE liver and found an expression signature distinct from the diet-based NAFLD models. We discovered a deregulation of glycolysis/gluconeogenesis pathway, especially a robust down regulation of the glycolytic enzyme aldolase b in the IL6-OE liver. Metabolomics of the IL6-OE liver showed accumulation of hexose monophosphates and their derivatives, which can act as precursors for triglyceride synthesis. Patients with the genetic disease Hereditary Fructose Intolerance (HFI) caused by ALDOLASE B deficiency also have a higher propensity to develop fatty liver disease.CONCLUSIONS Our study demonstrates a causative role for inflammation in intrahepatic lipid accumulation. Further, our results suggest that IL6-driven repression of glycolysis/gluconeogenesis, specifically aldolase b, may be a novel mechanism for development of fatty liver, especially in obesity-independent NAFLD.Competing Interest StatementThe authors have declared no competing interest.List of AbbreviationsNAFLDNon-Alcoholic Fatty Liver DiseaseIL6Interleukin 6OEOverexpressionHFIHigh Fructose IntoleranceNASHNon-Alcoholic SteatohepatitisSLESystemic Lupus ErythematosusIBDInflammatory Bowel DiseaseRARheumatoid ArthritisHFDHigh Fat dietqRT-PCRQuantitative Real-Time Polymerase Chain ReactionPPARPeroxisome Proliferator-Activated ReceptorDHAPDihydroxyacetone PhosphateView Full Text

molecular biology↗