Association of Smoking Status With the Risk of Type 2 Diabetes Among Young Adults: A Nationwide Cohort Study in South Korea.

INTRODUCTION: The longitudinal evidence between detailed parameters of smoking status and type 2 diabetes among young adults has been limited. We evaluated this association in young Korean adults. METHODS: This nationwide cohort study included 3 026 551 adults aged 20 to 39 years who underwent Korean National Health Insurance Service health examinations in 2009 and were followed up until the end of 2017. The participants were categorized according to smoking status, smoking duration, and smoking amount. The hazard ratios (HRs) and 95% CIs for type 2 diabetes were estimated using multivariable Cox proportional hazard regression analysis. RESULTS: During 8.2 years of follow-up, 71 952 cases of type 2 diabetes newly developed. Compared with never-smokers, independently increased HRs of type 2 diabetes were observed in ex-smokers (1.06, 95% CI = 1.04-1.09) and current smokers (1.39, 1.36-1.42). In these two groups, the type 2 diabetes risk increased with greater smoking duration and amount (p for trend <.001). The HRs of type 2 diabetes were higher in current smokers than in ex-smokers at the same lifetime smoking amount. The associations between smoking status and incident type 2 diabetes were stronger in men, individuals who did not drink heavily, and those without obesity. CONCLUSIONS: Among young adults, past and current smoking was associated with an increased risk of type 2 diabetes, and there was a dose-response association of smoking amount and duration with type 2 diabetes development. Appropriate interventions to help young adults cease smoking may help reduce the incidence of type 2 diabetes. IMPLICATIONS: Smoking was associated with an increased risk of type 2 diabetes among young adults, and the risk was shown to increase as amount and duration of smoking increased. Ceasing smoking in young adults may help reduce the incidence of type 2 diabetes.

mRNA therapy restores euglycemia and prevents liver tumors in murine model of glycogen storage disease.

Glycogen Storage Disease 1a (GSD1a) is a rare, inherited metabolic disorder caused by deficiency of glucose 6-phosphatase (G6Pase-α). G6Pase-α is critical for maintaining interprandial euglycemia. GSD1a patients exhibit life-threatening hypoglycemia and long-term liver complications including hepatocellular adenomas (HCAs) and carcinomas (HCCs). There is no treatment for GSD1a and the current standard-of-care for managing hypoglycemia (Glycosade®/modified cornstarch) fails to prevent HCA/HCC risk. Therapeutic modalities such as enzyme replacement therapy and gene therapy are not ideal options for patients due to challenges in drug-delivery, efficacy, and safety. To develop a new treatment for GSD1a capable of addressing both the life-threatening hypoglycemia and HCA/HCC risk, we encapsulated engineered mRNAs encoding human G6Pase-α in lipid nanoparticles. We demonstrate the efficacy and safety of our approach in a preclinical murine model that phenotypically resembles the human condition, thus presenting a potential therapy that could have a significant therapeutic impact on the treatment of GSD1a.

The relationship between metabolic syndrome and the incidence of colorectal cancer.

OBJECTIVES: This study evaluated the incidence of colorectal cancer (CRC) according to the number of metabolic syndrome (MetS) components. METHODS: Using health checkup and insurance claims data of 6,365,409 subjects, the occurrence of CRC according to stage of MetS by sex was determined from the date of the health checkup in 2009 until December 31, 2018. RESULTS: Cumulative incidence rates (CIR) of CRC in men and women was 3.9 and 2.8 per 1000 (p < 0.001), respectively. CIR of CRC for the normal, pre-MetS, and MetS groups in men was 2.6, 3.9, and 5.5 per 1000 (p < 0.001) and CIR in women was 2.1, 2.9, and 4.5 per 1000 (p < 0.001), respectively. Compared with the normal group, the hazard ratio (HR) of CRC for the pre-MetS group was 1.25 (95% CI 1.17-1.33) in men and 1.09 (95% CI 1.02-1.17) in women, and the HR of CRC for the MetS group was 1.54 (95% CI 1.43-1.65) in men and 1.39 (95% CI 1.26-1.53) in women after adjustment. CONCLUSIONS: We found that MetS is a risk factor for CRC in this study. Therefore, the prevention and active management of MetS would contribute to the prevention of CRC.

Study on the Relevance of Metabolic Syndrome and Incidence of Gastric Cancer in Korea.

(1) Background: This study aimed to determine the relevance between stages of metabolic syndrome (MS) progression and the incidence of gastric cancer utilizing a big data cohort for the national health checkup. (2) Methods: There were 7,785,098 study subjects, and three stages of metabolic syndrome were categorized using the health checkup results from 2009. Incidence of gastric cancer was traced and observed from the date of the health insurance benefit claim in 2009 until 31 December, 2016, and Cox hazard-proportional regression was performed to determine the risk of gastric cancer incidence based on the stage of progression for metabolic syndrome. (3) Results: Hazard ratio (HR) incidence rate for the MS group was 2.31 times higher than the normal group (95% CI 2.22⁻2.40) after adjustment (Model 4). The HR incidence rate of gastric cancer for the pre-MS group was 1.08 times higher (95% CI 1.04⁻1.12) than the normal group, while the HR incidence rate of gastric cancer for the MS group was 1.26 times higher (95% CI 1.2⁻1.32). (4) Conclusions: Causal relevance observed in this study between metabolic syndrome and incidence of gastric cancer was high. Promotion and education for active responses in the general population and establishment of appropriate metabolic syndrome management systems to prevent gastric cancer are needed.

G protein-coupled receptor kinases (GRKs) orchestrate biased agonism at the ß2-adrenergic receptor.

Biased agonists of G protein-coupled receptors (GPCRs), which selectively activate either G protein- or ß-arrestin-mediated signaling pathways, are of major therapeutic interest because they have the potential to show improved efficacy and specificity as drugs. Efforts to understand the mechanistic basis of this phenomenon have focused on the hypothesis that G proteins and ß-arrestins preferentially couple to distinct GPCR conformations. However, because GPCR kinase (GRK)-dependent receptor phosphorylation is a critical prerequisite for the recruitment of ß-arrestins to most GPCRs, GRKs themselves may play an important role in establishing biased signaling. We showed that an alanine mutant of the highly conserved residue tyrosine 219 (Y219A) in transmembrane domain five of the ß2-adrenergic receptor (ß2AR) was incapable of ß-arrestin recruitment, receptor internalization, and ß-arrestin-mediated activation of extracellular signal-regulated kinase (ERK), whereas it retained the ability to signal through G protein. We found that the impaired ß-arrestin recruitment in cells was due to reduced GRK-mediated phosphorylation of the ß2AR Y219A C terminus, which was recapitulated in vitro with purified components. Furthermore, in vitro ligation of a synthetically phosphorylated peptide onto the C terminus of ß2AR Y219A rescued both the initial recruitment of ß-arrestin and its engagement with the intracellular core of the receptor. These data suggest that the Y219A mutation generates a G protein-biased state primarily by conformational selection against GRK coupling, rather than against ß-arrestin. Together, these findings highlight the importance of GRKs in modulating the biased agonism of GPCRs.

Revealing the architecture of protein complexes by an orthogonal approach combining HDXMS, CXMS, and disulfide trapping.

Many cellular functions necessitate structural assemblies of two or more associated proteins. The structural characterization of protein complexes using standard methods, such as X-ray crystallography, is challenging. Herein, we describe an orthogonal approach using hydrogen-deuterium-exchange mass spectrometry (HDXMS), cross-linking mass spectrometry (CXMS), and disulfide trapping to map interactions within protein complexes. HDXMS measures changes in solvent accessibility and hydrogen bonding upon complex formation; a decrease in HDX rate could account for newly formed intermolecular or intramolecular interactions. To distinguish between inter- and intramolecular interactions, we use a CXMS method to determine the position of direct interface regions by trapping intermolecular residues in close proximity to various cross-linkers (e.g., disuccinimidyl adipate (DSA)) of different lengths and reactive groups. Both MS-based experiments are performed on high-resolution mass spectrometers (e.g., an Orbitrap Elite hybrid mass spectrometer). The physiological relevance of the interactions identified through HDXMS and CXMS is investigated by transiently co-expressing cysteine mutant pairs, one mutant on each protein at the discovered interfaces, in an appropriate cell line, such as HEK293. Disulfide-trapped protein complexes are formed within cells spontaneously or are facilitated by addition of oxidation reagents such as H2O2 or diamide. Western blotting analysis, in the presence and absence of reducing reagents, is used to determine whether the disulfide bonds are formed in the proposed complex interface in physiologically relevant milieus. The procedure described here requires 1-2 months. We demonstrate this approach using the ß2-adrenergic receptor-ß-arrestin1 complex as the model system.

Sortase ligation enables homogeneous GPCR phosphorylation to reveal diversity in ß-arrestin coupling.

The ability of G protein-coupled receptors (GPCRs) to initiate complex cascades of cellular signaling is governed by the sequential coupling of three main transducer proteins, G protein, GPCR kinase (GRK), and ß-arrestin. Mounting evidence indicates these transducers all have distinct conformational preferences and binding modes. However, interrogating each transducer's mechanism of interaction with GPCRs has been complicated by the interplay of transducer-mediated signaling events. For example, GRK-mediated receptor phosphorylation recruits and induces conformational changes in ß-arrestin, which facilitates coupling to the GPCR transmembrane core. Here we compare the allosteric interactions of G proteins and ß-arrestins with GPCRs' transmembrane cores by using the enzyme sortase to ligate a synthetic phosphorylated peptide onto the carboxyl terminus of three different receptors. Phosphopeptide ligation onto the ß2-adrenergic receptor (ß2AR) allows stabilization of a high-affinity receptor active state by ß-arrestin1, permitting us to define elements in the ß2AR and ß-arrestin1 that contribute to the receptor transmembrane core interaction. Interestingly, ligation of the identical phosphopeptide onto the ß2AR, the muscarinic acetylcholine receptor 2 and the µ-opioid receptor reveals that the ability of ß-arrestin1 to enhance agonist binding relative to G protein differs substantially among receptors. Furthermore, strong allosteric coupling of ß-arrestin1 correlates with its ability to attenuate, or "desensitize," G protein activation in vitro. Sortase ligation thus provides a versatile method to introduce complex, defined phosphorylation patterns into GPCRs, and analogous strategies could be applied to other classes of posttranslationally modified proteins. These homogeneously phosphorylated GPCRs provide an innovative means to systematically study receptor-transducer interactions.