Investigating inherent functional differences between human cardiac fibroblasts cultured from nondiabetic and Type 2 diabetic donors.

Introduction: Type 2 diabetes mellitus (T2DM) promotes adverse myocardial remodeling and increased risk of heart failure; effects that can occur independently of hypertension or coronary artery disease. As cardiac fibroblasts (CFs) are key effectors of myocardial remodeling, we investigated whether inherent phenotypic differences exist in CF derived from T2DM donors compared with cells from nondiabetic (ND) donors.

Methods: Cell morphology (cell area), proliferation (cell counting over 7-day period), insulin signaling [phospho-Akt and phospho-extracellular signal-regulated kinase (ERK) Western blotting], and mRNA expression of key remodeling genes [real-time reverse transcription-polymerase chain reaction (RT-PCR)] were compared in CF cultured from atrial tissue from 14 ND and 12 T2DM donors undergoing elective coronary artery bypass surgery.

Prevalence of loss-of-function FTO mutations in lean and obese individuals.

Objective: Single nucleotide polymorphisms (SNPs) in intron 1 of fat mass- and obesity-associated gene (FTO) are strongly associated with human adiposity, whereas Fto(-/-) mice are lean and Fto(+/-) mice are resistant to diet-induced obesity. We aimed to determine whether FTO mutations are disproportionately represented in lean or obese humans and to use these mutations to understand structure-function relationships within FTO.

Research Design And Methods: We sequenced all coding exons of FTO in 1,433 severely obese and 1,433 lean individuals.

Loss-of-function mutation in the dioxygenase-encoding FTO gene causes severe growth retardation and multiple malformations.

FTO is a nuclear protein belonging to the AlkB-related non-haem iron- and 2-oxoglutarate-dependent dioxygenase family. Although polymorphisms within the first intron of the FTO gene have been associated with obesity, the physiological role of FTO remains unknown. Here we show that a R316Q mutation, inactivating FTO enzymatic activity, is responsible for an autosomal-recessive lethal syndrome.

Dynamic states of the DNA repair enzyme AlkB regulate product release.

The 2-oxoglutarate (2OG)- and Fe(2+)-dependent dioxygenase AlkB couples the demethylation of modified DNA to the decarboxylation of 2OG. Extensive crystallographic analyses have shown no evidence of significant structural differences between complexes binding either 2OG or succinate. By using nuclear magnetic resonance spectroscopy, we have shown that the AlkB-succinate and AlkB-2OG complexes have significantly different dynamic properties in solution.

The obesity-associated FTO gene encodes a 2-oxoglutarate-dependent nucleic acid demethylase.

Variants in the FTO (fat mass and obesity associated) gene are associated with increased body mass index in humans. Here, we show by bioinformatics analysis that FTO shares sequence motifs with Fe(II)- and 2-oxoglutarate-dependent oxygenases. We find that recombinant murine Fto catalyzes the Fe(II)- and 2OG-dependent demethylation of 3-methylthymine in single-stranded DNA, with concomitant production of succinate, formaldehyde, and carbon dioxide.