Reciprocal Regulation of Hepatic TGF-ß1 and Foxo1 Controls Gluconeogenesis and Energy Expenditure.

Obesity and insulin resistance are risk factors for the pathogenesis of type 2 diabetes (T2D). Here, we report that hepatic TGF-ß1 expression positively correlates with obesity and insulin resistance in mice and humans. Hepatic TGF-ß1 deficiency decreased blood glucose levels in lean mice and improved glucose and energy dysregulations in diet-induced obese (DIO) mice and diabetic mice. Conversely, overexpression of TGF-ß1 in the liver exacerbated metabolic dysfunctions in DIO mice. Mechanistically, hepatic TGF-ß1 and Foxo1 are reciprocally regulated: fasting or insulin resistance caused Foxo1 activation, increasing TGF-ß1 expression, which, in turn, activated protein kinase A, stimulating Foxo1-S273 phosphorylation to promote Foxo1-mediated gluconeogenesis. Disruption of TGF-ß1→Foxo1→TGF-ß1 looping by deleting TGF-ß1 receptor II in the liver or by blocking Foxo1-S273 phosphorylation ameliorated hyperglycemia and improved energy metabolism in adipose tissues. Taken together, our studies reveal that hepatic TGF-ß1→Foxo1→TGF-ß1 looping could be a potential therapeutic target for prevention and treatment of obesity and T2D. ARTICLE HIGHLIGHTS: Hepatic TGF-ß1 levels are increased in obese humans and mice. Hepatic TGF-ß1 maintains glucose homeostasis in lean mice and causes glucose and energy dysregulations in obese and diabetic mice. Hepatic TGF-ß1 exerts an autocrine effect to promote hepatic gluconeogenesis via cAMP-dependent protein kinase-mediated Foxo1 phosphorylation at serine 273, endocrine effects on brown adipose tissue action, and inguinal white adipose tissue browning (beige fat), causing energy imbalance in obese and insulin-resistant mice. TGF-ß1→Foxo1→TGF-ß1 looping in hepatocytes plays a critical role in controlling glucose and energy metabolism in health and disease.

Towards a generic prototyping approach for therapeutically-relevant peptides and proteins in a cell-free translation system.

Advances in peptide and protein therapeutics increased the need for rapid and cost-effective polypeptide prototyping. While in vitro translation systems are well suited for fast and multiplexed polypeptide prototyping, they suffer from misfolding, aggregation and disulfide-bond scrambling of the translated products. Here we propose that efficient folding of in vitro produced disulfide-rich peptides and proteins can be achieved if performed in an aggregation-free and thermodynamically controlled folding environment. To this end, we modify an E. coli-based in vitro translation system to allow co-translational capture of translated products by affinity matrix. This process reduces protein aggregation and enables productive oxidative folding and recycling of misfolded states under thermodynamic control. In this study we show that the developed approach is likely to be generally applicable for prototyping of a wide variety of disulfide-constrained peptides, macrocyclic peptides with non-native bonds and antibody fragments in amounts sufficient for interaction analysis and biological activity assessment.