d2ome, Software for in Vivo Protein Turnover Analysis Using Heavy Water Labeling and LC-MS, Reveals Alterations of Hepatic Proteome Dynamics in a Mouse Model of NAFLD
40S ribosomal proteins; algorithm; amino-acids; Biochemistry & Molecular Biology; dna; in vivo protein turnover; isotopomer; Mass spectrometry; metabolic labeling; NAFLD; nonlinear least-squares modeling; peak detection and integration; proliferation; protein half-life; proteome dynamics; proteostasis; quantification; rates; respiratory-chain; steatosis; UPR
Metabolic labeling with heavy water followed by LC-MS is a high throughput approach to study proteostasis in vivo. Advances in mass spectrometry and sample processing have allowed consistent detection of thousands of proteins at multiple time points. However, freely available automated bioinformatics tools to analyze and extract protein decay rate constants are lacking. Here, we describe d2ome-a robust, automated software solution for in vivo protein turnover analysis. d2ome is highly scalable, uses innovative approaches to nonlinear fitting, implements Grubbs' outlier detection and removal, uses weighted-averaging of replicates, applies a data dependent elution time windowing, and uses mass accuracy in peak detection. Here, we discuss the application of d2ome in a comparative study of protein turnover in the livers of normal vs Western diet-fed LDLR-/- mice (mouse model of nonalcoholic fatty liver disease), which contained 256 LC-MS experiments. The study revealed reduced stability of 40S ribosomal protein subunits in the Western diet-fed mice.
Sadygov R G; Avva J; Rahman M; Lee K; Ilchenko S; Kasumov T; Borzou A
Journal of Proteome Research
2018
2018-11
Journal Article
<a href="http://doi.org/10.1021/acs.jproteorne.8b00417" target="_blank" rel="noreferrer noopener">10.1021/acs.jproteorne.8b00417</a>
Leptin in Whales: Validation and Measurement of mRNA Expression by Absolute Quantitative Real-Time PCR
obesity; mammals; Science & Technology - Other Topics; resistance; mass; weight; quantification; housekeeping genes; reference genes; rt-pcr; serum leptin
Leptin is the primary hormone in mammals that regulates adipose stores. Arctic adapted cetaceans maintain enormous adipose depots, suggesting possible modifications of leptin or receptor function. Determining expression of these genes is the first step to understanding the extreme physiology of these animals, and the uniqueness of these animals presents special challenges in estimating and comparing expression levels of mRNA transcripts. Here, we compare expression of two model genes, leptin and leptin-receptor gene-related product (OB-RGRP), using two quantitative real-time PCR (qPCR) methods: "relative'' and "absolute''. To assess the expression of leptin and OB-RGRP in cetacean tissues, we first examined how relative expression of those genes might differ when normalized to four common endogenous control genes. We performed relative expression qPCR assays measuring the amplification of these two model target genes relative to amplification of 18S ribosomal RNA (18S), ubiquitously expressed transcript (Uxt), ribosomal protein 9 (Rs9) and ribosomal protein 15 (Rs15) endogenous controls. Results demonstrated significant differences in the expression of both genes when different control genes were employed; emphasizing a limitation of relative qPCR assays, especially in studies where differences in physiology and/or a lack of knowledge regarding levels and patterns of expression of common control genes may possibly affect data interpretation. To validate the absolute quantitative qPCR methods, we evaluated the effects of plasmid structure, the purity of the plasmid standard preparation and the influence of type of qPCR "background'' material on qPCR amplification efficiencies and copy number determination of both model genes, in multiple tissues from one male bowhead whale. Results indicate that linear plasmids are more reliable than circular plasmid standards, no significant differences in copy number estimation based upon background material used, and that the use of ethanol precipitated, linearized plasmid preparation produce the most reliable results.
Ball H C; Holmes R K; Londraville R L; Thewissen J G M; Duff R J
PLOS ONE
2013
2013-01
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1371/journal.pone.0054277" target="_blank" rel="noreferrer noopener">10.1371/journal.pone.0054277</a>