Cold-induced thermogenesis is an energy-demanding process that protects endotherms against a reduction in ambient temperature. Using non-targeted liquid chromatography-mass spectrometry-based lipidomics, we identified elevated levels of plasma acylcarnitines in response to the cold. We found that the liver undergoes a metabolic switch to provide fuel for brown fat thermogenesis by producing acylcarnitines. Cold stimulates white adipocytes to release free fatty acids that activate the nuclear receptor HNF4α, which is required for acylcarnitine production in the liver and adaptive thermogenesis. Once in circulation, acylcarnitines are transported to brown adipose tissue, while uptake into white adipose tissue and liver is blocked. Finally, a bolus of L-carnitine or palmitoylcarnitine rescues the cold sensitivity seen with aging. Our data highlight an elegant mechanism whereby white adipose tissue provides long-chain fatty acids for hepatic carnitilation to generate plasma acylcarnitines as a fuel source for peripheral tissues in mice.
Statistical software package for data analysis, hypothesis testing, and modeling. The software can capable perform mathematical calculations (including biostatistics) and graphical plotting such as curve fitting (nonlinear regression) and scientific graphing.
Software which can acquire, analyze, manage, and share mass spectrometry data. MassLynx controls any Waters mass spectrometry system, from sample and solvent management components to mass spectrometer and auxiliary detectors. The software can acquire nominal mass, exact mass, MS/MS and exact mass MS/MS data. The software system also maintains and consolidates all user sample data. Optional Application Manager programs provide additional information for specific MS analyses and data.
Web-based analytical pipeline that offers access to commonly used procedures for metabolomic data processing, normalization, and multivariate statistical analysis, as well as data annotation. It is capable of processing and statistical analysis of metabolomics data, metabolite set enrichment analysis and metabolic pathway analysis, advanced two-factor and time series analyses, and support for biomarker analysis, power analysis, and integration with gene expression data.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to SciCrunch, however this is not currently a free service.