Portal vein-enriched metabolites as intermediate regulators of the gut microbiome in insulin resistance.

Diet and obesity contribute to insulin resistance and type 2 diabetes, in part via the gut microbiome. To explore the role of gut-derived metabolites in this process, we assessed portal/peripheral blood metabolites in mice with different risks of obesity/diabetes, challenged with a high-fat diet (HFD) + antibiotics. In diabetes/obesity-prone C57BL/6J mice, 111 metabolites were portally enriched and 74 were peripherally enriched, many of which differed in metabolic-syndrome-resistant 129S1/129S6 mice.

Reversible compromise of physiological resilience by accumulation of heteroplasmic mtDNA mutations.

Somatically acquired mitochondrial DNA mutations accumulate with age, but the mechanisms and consequences are poorly understood. Here we show that transient injuries induce a burst of persistent mtDNA mutations that impair resilience to future injuries. mtDNA mutations suppressed energy-intensive nucleotide metabolism.

Abnormal Vaginal Microbiota Associated with miRNA Targeting the HIV-Host Interactome.

Understanding the molecular mechanisms underlying the ability of vaginal dysbiosis to alter the mucosal barrier to HIV acquisition is an essential step toward prevention. We hypothesized that micro(mi)-RNAs dysregulated by vaginal pathobiont bacteria epigenetically control host pathways exploited by the virus. The impact of these endogenous non-coding short RNAs on the anti-viral mucosal barrier function in the female reproductive tract is largely unknown.

Maternal Physical Activity and its Relationship to the Human Milk Metabolome and Infant Body Composition.

Context: Exercise is recommended for postpartum health, but its impacts on breastmilk composition and offspring are understudied.

Objective: To test whether the breastmilk metabolome is altered with (i) acute exercise and/or (ii) habitual physical activity, and (iii) whether exercise-altered metabolites are associated with infant adiposity.

Design: Milk metabolites were assessed before and after acute exercise and in association with habitual activity score in two independent cohorts.

Cell-intrinsic insulin signaling defects in human iPS cell-derived hepatocytes in type 2 diabetes.

Hepatic insulin resistance is central to type 2 diabetes (T2D) and metabolic syndrome, but defining the molecular basis of this defect in humans is challenging because of limited tissue access. Utilizing inducible pluripotent stem cells differentiated into hepatocytes from control individuals and patients with T2D and liquid chromatography with tandem mass spectrometry-based (LC-MS/MS-based) phosphoproteomics analysis, we identified a large network of cell-intrinsic alterations in signaling in T2D. Over 300 phosphosites showed impaired or reduced insulin signaling, including losses in the classical insulin-stimulated PI3K/AKT cascade and their downstream targets.

Type 2 diabetes impacts DNA methylation in human sperm.

Aims/hypothesis: Disorders of the reproductive system, including hypogonadism and reduced fertility, are an under-recognized complication of diabetes. Based on experimental data in mice, hyperglycemia and obesity may modify epigenetic marks in sperm and impact health and development of offspring, but data are more limited in humans. Thus, we sought to study the impact of type 2 diabetes and glycemic control on sperm quality and DNA methylation.

Sex Differences in Endocannabinoid and Inflammatory Markers Associated with Posttraumatic Stress Disorder.

Background: Posttraumatic stress disorder (PTSD) is one of the most sex-polarized psychiatric disorders, with women exhibiting twice the prevalence of men. The biological mechanisms underlying this sex disparity are not fully understood. Growing evidence suggests that alterations of the stress-buffering endocannabinoid (eCB) system and heightened inflammation are central to PTSD pathophysiology and may contribute to sex-biases in PTSD risk and severity.

Gestational Diabetes, the Human Milk Metabolome, and Infant Growth and Adiposity.

Importance: Gestational diabetes (GD) is linked to health risks for the birthing parent and infant. The outcomes of GD on human milk composition are mostly unknown.

Objective: To determine associations between GD, the human milk metabolome, and infant growth and body composition.

Circulating proteins linked to apoptosis processes and fast development of end-stage kidney disease in diabetes.

Many circulating proteins are associated with risk of ESKD, but their source and the biological pathways/disease processes they represent are unclear. Using OLINK proteomics platform, concentrations of 455 proteins were measured in plasma specimens obtained at baseline from 399 individuals with diabetes. Elevated concentrations of 46 circulating proteins were associated (P < 1 × 10-5) with development of ESKD (n = 143) during 7-15 years of follow-up.

Postprandial metabolomics analysis reveals disordered serotonin metabolism in post-bariatric hypoglycemia.

BACKGROUNDBariatric surgery is a potent therapeutic approach for obesity and type 2 diabetes but can be complicated by post-bariatric hypoglycemia (PBH). PBH typically occurs 1-3 hours after meals, in association with exaggerated postprandial levels of incretins and insulin.METHODSTo identify mediators of disordered metabolism in PBH, we analyzed the plasma metabolome in the fasting state and 30 and 120 minutes after mixed meal in 3 groups: PBH (n = 13), asymptomatic post-Roux-en-Y gastric bypass (post-RYGB) (n = 10), and nonsurgical controls (n = 8).

Matrisome proteomics reveals novel mediators of muscle remodeling with aerobic exercise training.

Skeletal muscle has a unique ability to remodel in response to stimuli such as contraction and aerobic exercise training. Phenotypic changes in muscle that occur with training such as a switch to a more oxidative fiber type, and increased capillary density contribute to the well-known health benefits of aerobic exercise. The muscle matrisome likely plays an important role in muscle remodeling with exercise.

ScreenDMT reveals DiHOMEs are replicably inversely associated with BMI and stimulate adipocyte calcium influx.

Activating brown adipose tissue (BAT) improves systemic metabolism, making it a promising target for metabolic syndrome. BAT is activated by 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME), which we previously identified to be inversely associated with BMI and which directly improves metabolism in multiple tissues. Here we profile plasma lipidomics from 83 people and test which lipids' association with BMI replicates in a concordant direction using our novel tool ScreenDMT, whose power and validity we demonstrate via mathematical proofs and simulations.

Circulating Metabolite Biomarkers of Glycemic Control in Youth-Onset Type 2 Diabetes.

Objective: We aimed to identify metabolites associated with loss of glycemic control in youth-onset type 2 diabetes.

Research Design And Methods: We measured 480 metabolites in fasting plasma samples from the TODAY (Treatment Options for Type 2 Diabetes in Adolescents and Youth) study. Participants (N = 393; age 10-17 years) were randomly assigned to metformin, metformin plus rosiglitazone, or metformin plus lifestyle intervention.

Plantar Skin Exhibits Altered Physiology, Constitutive Activation of Wound-Associated Phenotypes, and Inherently Delayed Healing.

Wound research has typically been performed without regard for where the wounds are located on the body, despite well-known heterogeneities in physical and biological properties between different skin areas. The skin covering the palms and soles is highly specialized, and plantar ulcers are one of the most challenging and costly wound types to manage. Using primarily the porcine model, we show that plantar skin is molecularly and functionally more distinct from nonplantar skin than previously recognized, with unique gene and protein expression profiles, broad alterations in cellular functions, constitutive activation of many wound-associated phenotypes, and inherently delayed healing.

Sustained hyperglycemia specifically targets translation of mRNAs for insulin secretion.

Pancreatic β cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair β cell insulin secretion and have been shown experimentally to suppress insulin translation.

FoxK1 associated gene regulatory network in hepatic insulin action and its relationship to FoxO1 and insulin receptor mediated transcriptional regulation.

Objective: Insulin acts on the liver via changes in gene expression to maintain glucose and lipid homeostasis. This study aimed to the Forkhead box protein K1 (FOXK1) associated gene regulatory network as a transcriptional regulator of hepatic insulin action and to determine its role versus FoxO1 and possible actions of the insulin receptor at the DNA level.

Methods: Genome-wide analysis of FoxK1 binding were studied by chromatin immunoprecipitation sequencing and compared to those for IR and FoxO1.

Sustained hyperglycemia specifically targets translation of mRNAs for insulin secretion.

Pancreatic β-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair β-cell insulin secretion and have been shown experimentally to suppress insulin translation.

ScreenDMT reveals linoleic acid diols replicably associate with BMI and stimulate adipocyte calcium fluxes.

Activating brown adipose tissue (BAT) improves systemic metabolism, making it a promising target for metabolic syndrome. BAT is activated by 12, 13-dihydroxy-9Z-octadecenoic acid (12, 13-diHOME), which we previously identified to be inversely associated with BMI and which directly improves metabolism in multiple tissues. Here we profile plasma lipidomics from a cohort of 83 people and test which lipids' association with BMI replicates in a concordant direction using our novel tool ScreenDMT, whose power and validity we demonstrate via mathematical proofs and simulations.

Fructose induced KHK-C can increase ER stress independent of its effect on lipogenesis to drive liver disease in diet-induced and genetic models of NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is a liver manifestation of metabolic syndrome, and is estimated to affect one billion individuals worldwide. An increased intake of a high-fat diet (HFD) and sugar-sweetened beverages are risk-factors for NAFLD development, but how their combined intake promotes progression to a more severe form of liver injury is unknown. Here we show that fructose metabolism via ketohexokinase (KHK) C isoform leads to unresolved endoplasmic reticulum (ER) stress when coupled with a HFD intake.

Continuous glucose monitoring in patients with post-bariatric hypoglycaemia reduces hypoglycaemia and glycaemic variability.

Aim: To determine whether continuous glucose monitoring (CGM) can reduce hypoglycaemia in patients with post-bariatric hypoglycaemia (PBH).

Materials And Methods: In an open-label, nonrandomized, pre-post design with sequential assignment, CGM data were collected in 22 individuals with PBH in two sequential phases: (i) masked (no access to sensor glucose or alarms); and (ii) unmasked (access to sensor glucose and alarms for low or rapidly declining sensor glucose). Twelve participants wore the Dexcom G4 device for a total of 28 days, while 10 wore the Dexcom G6 device for a total of 20 days.

Unique ligand and kinase-independent roles of the insulin receptor in regulation of cell cycle, senescence and apoptosis.

Insulin acts through the insulin receptor (IR) tyrosine kinase to exert its classical metabolic and mitogenic actions. Here, using receptors with either short or long deletion of the β-subunit or mutation of the kinase active site (K1030R), we have uncovered a second, previously unrecognized IR signaling pathway that is intracellular domain-dependent, but ligand and tyrosine kinase-independent (LYK-I). These LYK-I actions of the IR are linked to changes in phosphorylation of a network of proteins involved in the regulation of extracellular matrix organization, cell cycle, ATM signaling and cellular senescence; and result in upregulation of expression of multiple extracellular matrix-related genes and proteins, down-regulation of immune/interferon-related genes and proteins, and increased sensitivity to apoptosis.

Leucine-973 is a crucial residue differentiating insulin and IGF-1 receptor signaling.

Insulin and IGF-1 receptors (IR and IGF1R) are highly homologous and share similar signaling systems, but each has a unique physiological role, with IR primarily regulating metabolic homeostasis and IGF1R regulating mitogenic control and growth. Here, we show that replacement of a single amino acid at position 973, just distal to the NPEY motif in the intracellular juxtamembrane region, from leucine, which is highly conserved in IRs, to phenylalanine, the highly conserved homologous residue in IGF1Rs, resulted in decreased IRS-1/PI3K/Akt/mTORC1 signaling and increased Shc/Gab1/MAPK cell cycle signaling. As a result, cells expressing L973F-IR exhibited decreased insulin-induced glucose uptake, increased cell growth, and impaired receptor internalization.