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MYC proto-oncogene dysregulation alters metabolic, translational, cell cycle and other functions in ways that support tumor induction and maintenance. Myc+/- mice are healthier and longer-lived than control mice but the long-term ramifications of more complete Myc loss remain unknown. We now describe the life-long consequences of body-wide Myc inactivation initiated post-natally. “MycKO” mice rapidly acquire numerous features of premature aging including altered body composition and habitus, metabolic dysfunction, hepatic steatosis and the dysregulation of numerous gene sets involved in functions that normally deteriorate with aging. Yet, MycKO mice have an extended life span that correlates with a 4-5-fold lower lifetime cancer incidence. Aging tissues from normal mice and humans deregulate many of the same gene sets as do young MycKO mice while also down-regulating Myc and many of its target genes. Normal aging and its associated cancer predisposition are thus highly linked via Myc and its target genes and can be genetically separated.

Adolescents with diabetes mellitus (DM) experience depression 2-3 times higher than the general population. Little is known about the impact of the COVID pandemic. We aimed to identify the prevalence of depression among youth with DM before and during the pandemic and associated factors in a large academic children’s hospital. Patient health Questionnaire-9 (PHQ-9) screens completed in fall 20 and 2020 (n=216 vs. 194 respectively) were reviewed. 187 subjects (81%) completed the screen at both periods (54% female, 97% white, 97% with type 1 DM (T1D) , mean (SD) age 15.1 (2.7) years, duration of DM 7.2 (4.2) years) . Among youth with T1D, 55% used insulin pumps and 64% continuous glucose monitor (CGM) . When comparing 20to 2020, median [IQR] PHQ-9 score (1 [0-3] vs. 0 [0-3], p=0.76) or rates of depression (17 vs. 15%, p=0.65) were not different. In 2011%, 4% and 2% had mild (PHQ-9 score 5-9) , moderate (score 10-14) , and severe (score >14) depression respectively with similar rates in 2020 at 10%, 2% and 3% There was no difference in mean HbA1c between 20 and 2020 (8.2±1.7 vs. 8.2± 1.8% respectively, p=0.99) . Using 20data, PHQ-9 score was significantly positively correlated with HbA1c (rho=0.22, p=0.003) and BMI z-score (rho=0.22, p=0.003) , but not to age (rho-0.02, p=0.73) , or duration of diabetes (rho=0.04, p=0.55) . Depression was more prevalent in females (21% vs. 12%, p=0.09) and in youth with no CGM use (24 vs. 12%, p=0.047) . Suicidal ideation was reported in 4 (2%) of youth in 20 and 3 (1.5%) in 2020. Our results suggest that the prevalence/severity of depression during the first year of the pandemic did not change in youth with DM compared to the previous year, the reason perhaps being that ∼ 90% of patients in our institution continued to being followed up, albeit virtually, during the pandemic. Still, almost 1/5 of adolescents with DM scored positive for depression highlighting the need to support the behavioral needs of youth with T1D. Disclosure S.Sriram: None. L.M.Leikam: None. C.March: None. J.Schreiber: None. R.Muzumdar: None. I.Libman: Consultant; Novo Nordisk.

Acute myocardial infarction (MI) is one of the leading causes of death worldwide. Early identification of ischemia and establishing reperfusion remain cornerstones in the treatment of MI, as mortality and morbidity can be significantly reduced by establishing reperfusion to the affected areas. The aim of the current study was to investigate the metabolomic changes in the serum in a swine model of MI induced by ischemia and reperfusion (I/R) injury, and to identify circulating metabolomic biomarkers for myocardial injury at different phases. Female Yucatan minipigs were subjected to 60 min of ischemia followed by reperfusion, and serum samples were collected at baseline, 60 min of ischemia, 4 h of reperfusion, and 24 h of reperfusion. Circulating metabolites were analyzed using an untargeted metabolomic approach. A bioinformatic approach revealed that serum metabolites show distinct profiles during ischemia and during early and late reperfusion. Some notable changes during ischemia include accumulation of metabolites that indicate impaired mitochondrial function and N-terminally modified amino acids. Changes in branched-chain amino-acid metabolites were noted during early reperfusion, while bile acid pathway derivatives and intermediates predominated in the late reperfusion phases. This indicates a potential for such an approach toward identification of the distinct phases of ischemia and reperfusion in clinical situations.

Physiologic adaptations in the postnatal period, along with gradual establishment of enteral feeding, help maintain plasma glucose concentrations in the neonatal period. The definition of normal plasma glucose in the neonatal period has been a subject of debate because of a lack of evidence linking a set plasma or blood glucose concentration to clinical symptoms or predictors of short- and long-term outcomes. However, there is consensus that maintaining plasma glucose in the normal range for age is important to prevent immediate and long-term neurodevelopmental consequences of hypoglycemia or hyperglycemia. The specific management strategy for abnormal glucose levels in neonates depends on the underlying etiology, and interventions could include nutritional changes, medications, hormone therapy, or even surgery. Here, we will review the physiological processes that help maintain plasma glucose in newborns and discuss the approach to a newborn with disordered glucose homeostasis, with an emphasis on the endocrine basis of abnormal glucose homeostasis.

The purpose of this cross-sectional, descriptive, pilot study was to examine the correlations in sleep between caregivers (≥18 years) and young (6–12 years) children with type 1 diabetes. Sleep was measured in both parent and child over 7 days using actigraphy and a sleep diary. Parents completed questionnaires on sleep, stress, depressive symptoms, and demographics. Children completed pediatric anxiety and fatigue questionnaires, and A1C (Hemoglobin A1c) was documented at clinic. Descriptive statistics and Pearson correlations were used to analyze data. Parents ( N = 18, mean age: 39.3 ± 5.4 years, 100% Caucasian, 83% mothers) and children ( N = 18, mean age: 9.6 ± 2.4 years, diagnosed for mean 3.0 ± 2.4 years, 66% female, mean A1C: 7.5 ± 0.8%) were recruited. Strong to moderate correlations were found for several measures including sleep measures based on actigraphy: mean sleep duration (hours; 7.6 ± 0.7 for parents and 8.8 ± 0.8 for children; r = .638, p = .004), mean sleep efficiency ( r = .823, p < .001), and mean daily wake after sleep onset (minutes; r = .530, p = .024).

Hepatic inflammation is culpable for the evolution of asymptomatic steatosis to nonalcoholic steatohepatitis (NASH). Hepatic inflammation results from abnormal macrophage activation. We found that FoxO1 links overnutrition to hepatic inflammation by regulating macrophage polarization and activation. FoxO1 was upregulated in hepatic macrophages, correlating with hepatic inflammation, steatosis, and fibrosis in mice and patients with NASH. Myeloid cell conditional FoxO1 knockout skewed macrophage polarization from proinflammatory M1 to the antiinflammatory M2 phenotype, accompanied by a reduction in macrophage infiltration in liver. These effects mitigated overnutrition-induced hepatic inflammation and insulin resistance, contributing to improved hepatic metabolism and increased energy expenditure in myeloid cell FoxO1-knockout mice on a high-fat diet. When fed a NASH-inducing diet, myeloid cell FoxO1-knockout mice were protected from developing NASH, culminating in a reduction in hepatic inflammation, steatosis, and fibrosis. Mechanistically, FoxO1 counteracts Stat6 to skew macrophage polarization from M2 toward the M1 signature to perpetuate hepatic inflammation in NASH. FoxO1 appears to be a pivotal mediator of macrophage activation in response to overnutrition and a therapeutic target for ameliorating hepatic inflammation to stem the disease progression from benign steatosis to NASH.

Despite advances in management, many young adolescents with T1D continue to struggle. Psychosocial factors play a major role. The T1D HFW Program is an innovative strategy to improve the adherence to medical regimens, including self-management and self-efficacy in high-risk youth. It is based on HFW, an evidence-based behavioral health concept described as a structured, team-based and individualized process that includes members who have experience either living with or raising a child with T1D. The aim of this pilot study is to test the feasibility and impact of this intervention in youth 11 to 16 years with T1D followed in a large academic diabetes center who are struggling with their management as defined by poor glycemic control and/or repeated emergency room visits and/or hospitalizations. Outcomes include assessment for behavioral, psychosocial and diabetes related measures with validated instruments. Seventeen youth enrolled and participated so far (58% females, 58% Caucasian, 23% African American, mean age 14±1.4 years, T1D duration 7.5±3.5 years, HbA1c at entry 10.3±2.3%, 65% with a deterioration in HbA1c, 45% prior diabetes related hospitalizations). A significant percent (57%) reported at least one traumatic experience including bullying (66%), witnessing violence (50%), physical/emotional abuse (33%). To date, eight families have transitioned out of the program after a mean of 6.5 months with 62.5% showing improvement and 25% no deterioration in HbA1c. Youth scoring positive for moderate depression on the PHQ-9 went from 27% to 9%. 1/3 of youth indicated positive results for generalized anxiety by the Screen for Child Anxiety Disorders (SCARED) with no change upon finishing the program. 60% of caregivers indicated a positive score on the Diabetes Distress Scale at start, which decreased to 20%. The T1D HFW program through personalized plans with identified support systems may be a promising strategy for youth struggling with T1D. Disclosure J. Schreiber: None. A. G. Nevin: None. L. Jones: None. M. W. Payne: None. K. C. Nash: None. R. Muzumdar: None. I. Libman: Advisory Panel; Self; Novo Nordisk. Funding Children’s Hospital of Pittsburgh Foundation

Dicarboxylic fatty acids, taken as a nutritional supplement or produced endogenously via omega oxidation of monocarboxylic fatty acids, may have therapeutic potential for rare inborn errors of metabolism as well as common metabolic diseases such as type 2 diabetes. Breakdown of dicarboxylic acids yields acetyl-CoA and succinyl-CoA as products, the latter of which is anaplerotic for the TCA cycle. However, little is known about the metabolic pathways responsible for degradation of dicarboxylic acids. Here, we demonstrated with whole-cell fatty acid oxidation assays that both mitochondria and peroxisomes contribute to dicarboxylic acid degradation. Several mitochondrial acyl-CoA dehydrogenases were tested for activity against dicarboxylyl-CoAs. Medium-chain acyl-CoA dehydrogenase (MCAD) exhibited activity with both six and 12 carbon dicarboxylyl-CoAs, and the capacity for dehydrogenation of these substrates was significantly reduced in MCAD knockout mouse liver. However, when dicarboxylic acids were fed to normal mice, the expression of MCAD did not change, while expression of peroxisomal fatty acid oxidation enzymes was greatly upregulated. In conclusion, mitochondrial fatty acid oxidation, and in particular MCAD, contributes to dicarboxylic acid degradation, but feeding dicarboxylic acids induces only the peroxisomal pathway.

Humanin is an endogenous mitochondria-derived peptide that plays critical roles in oxidative stress, inflammation and CAD. In this study, we measured the levels of circulating humanin, markers of oxidative stress and inflammation in patients with unstable angina and MI and studied the relationship between these parameters and major adverse cardiac events (MACE).A total of 327 subjects were recruited from the inpatient department at First Hospital of Jilin University and divided into 3 groups [control, angina and myocardial infarction (MI)] based on the clinical data and the results of the angiography. Serum humanin and thiobarbituric acid reactive substances (TBARS) were measured at the time of initial admission. The hospitalization data and MACE of all patients were collected.Circulating humanin levels were lower in the angina group compared to controls [124.22 ± 63.02 vs. 157.77 ± 99.93 pg/ml, p 0.05] and even lower in MI patients [67.17 ± 24.35 pg/ml, p 0.05 vs controls] and oxidative stress marker were higher in MI patients compared to the control and angina groups [12.94 ± 4.55 vs. 8.26 ± 1.66 vs. 9.06 ± 2.47 umol/ml, p 0.05]. Lower circulating humanin levels was an independent risk factor of MI patients. Circulating humanin levels could be used to predict MACE in angina group.Lower circulating humanin levels was an independent risk factor for CAD, and a potential prognostic marker for mild CAD.Humanin may become a new index for the diagnosis and treatment of CAD.

Visual Abstract, Highlights • A mitochondrial-derived peptide therapy, HNG, was safe and was delivered as adjunctive therapy with standard-of-care reperfusion in a translational large animal model of myocardial ischemia/reperfusion injury. • HNG reduced infarct size per area-at-risk by 41% with an ischemic time of 60 min followed by 48 h of reperfusion. • The infarct-sparing effects of HNG were abolished when the ischemic time was increased to 75 min followed by 48 h of reperfusion. • The use of rigorous translational large animal models that account for clinically relevant variables is a prerequisite to better predict the clinical efficacy and outcomes of novel therapeutic strategies., Summary With the complexities that surround myocardial ischemia/reperfusion (MI/R) injury, therapies adjunctive to reperfusion that elicit beneficial pleiotropic effects and do not overlap with standard of care are necessary. This study found that the mitochondrial-derived peptide S14G-humanin (HNG) (2 mg/kg), an analogue of humanin, reduced infarct size in a large animal model of MI/R. However, when ischemic time was increased, the infarct-sparing effects were abolished with the same dose of HNG. Thus, although the 60-min MI/R study showed that HNG cardioprotection translates beyond small animal models, further studies are needed to optimize HNG therapy for longer, more patient-relevant periods of cardiac ischemia.

The incidence of diabetes mellitus has significantly increased among women of childbearing age, and it has been shown that prenatal exposure to maternal diabetes increases the risk of associated congenital anomalies of the kidney. Congenital anomalies of the kidney are among the leading causes of chronic kidney disease in children. To better understand the effect of maternal diabetes on kidney development, we analyzed wild-type offspring (DM_Exp) of diabetic Ins2+/C96Ymice (Akita mice). DM_Exp mice at postnatal day 34 have a reduction of ~20% in the total nephron number compared with controls, using the gold standard physical dissector/fractionator method. At the molecular level, the expression of the nephron progenitor markers sine oculis homeobox homolog 2 and Cited1 was increased in DM_Exp kidneys at postnatal day 2. Conversely, the number of early developing nephrons was diminished in DM_Exp kidneys. This was associated with decreased expression of the intracellular domain of Notch1 and the canonical Wnt target lymphoid enhancer binding factor 1. Together, these data suggest that the diabetic intrauterine environment impairs the differentiation of nephron progenitors into nephrons, possibly by perturbing the Notch and Wnt/β-catenin signaling pathways.

The Native American Pima population has the highest incidence of insulin resistance (IR) and type 2 diabetes mellitus (T2DM) of any reported population, but the pathophysiologic mechanism is unknown. Genetic studies in Pima Indians have linked acyl-CoA dehydrogenase 10 (ACAD10) gene polymorphisms, among others, to this predisposition. The gene codes for a protein with a C-terminus region that is structurally similar to members of a family of flavoenzymes-the acyl-CoA dehydrogenases (ACADs)-that catalyze α,β-dehydrogenation reactions, including the first step in mitochondrial FAO (FAO), and intermediary reactions in amino acids catabolism. Dysregulation of FAO and an increase in plasma acylcarnitines are recognized as important in the pathophysiology of IR and T2DM. To investigate the deficiency of ACAD10 as a monogenic risk factor for T2DM in human, an Acad-deficient mouse was generated and characterized. The deficient mice exhibit an abnormal glucose tolerance test and elevated insulin levels. Blood acylcarnitine analysis shows an increase in long-chain species in the older mice. Nonspecific variable pattern of elevated short-terminal branch-chain acylcarnitines in a variety of tissues was also observed. Acad10 mice accumulate excess abdominal adipose tissue, develop an early inflammatory liver process, exhibit fasting rhabdomyolysis, and have abnormal skeletal muscle mitochondria. Our results identify Acad10 as a genetic determinant of T2DM in mice and provide a model to further investigate genetic determinants for insulin resistance in humans.

In humans, low levels of growth hormone (GH) and its mediator, IGF-1, associate with hepatic lipid accumulation. In mice, congenital liver-specific ablation of the GH receptor (GHR) results in reductions in circulating IGF-1 and hepatic steatosis, associated with systemic insulin resistance. Due to the intricate relationship between GH and IGF-1, the relative contribution of each hormone to the development of hepatic steatosis is unclear. Our goal was to dissect the mechanisms by which hepatic GH resistance leads to steatosis and overall insulin resistance, independent of IGF-1. We have generated a combined mouse model with liver-specific ablation of GHR in which we restored liver IGF-1 expression via the hepatic IGF-1 transgene. We found that liver GHR ablation leads to increases in lipid uptake, de novo lipogenesis, hyperinsulinemia, and hyperglycemia accompanied with severe insulin resistance and increased body adiposity and serum lipids. Restoration of IGF-1 improved overall insulin sensitivity and lipid profile in serum and reduced body adiposity, but was insufficient to protect against steatosis-induced hepatic inflammation or oxidative stress. We conclude that the impaired metabolism in states of GH resistance results from direct actions of GH on lipid uptake and de novo lipogenesis, whereas its actions on extrahepatic tissues are mediated by IGF-1.

Mitochondria are key players in aging and in the pathogenesis of age-related diseases. Recent mitochondrial transcriptome analyses revealed the existence of multiple small mRNAs transcribed from mitochondrial DNA (mtDNA). Humanin (HN), a peptide encoded in the mtDNA 16S ribosomal RNA region, is a neuroprotective factor. An in silico search revealed six additional peptides in the same region of mtDNA as humanin; we named these peptides small humanin-like peptides (SHLPs). We identified the functional roles for these peptides and the potential mechanisms of action. The SHLPs differed in their ability to regulate cell viability in vitro. We focused on SHLP2 and SHLP3 because they shared similar protective effects with HN. Specifically, they significantly reduced apoptosis and the generation of reactive oxygen species, and improved mitochondrial metabolism in vitro. SHLP2 and SHLP3 also enhanced 3T3-L1 pre-adipocyte differentiation. Systemic hyperinsulinemic-euglycemic clamp studies showed that intracerebrally infused SHLP2 increased glucose uptake and suppressed hepatic glucose production, suggesting that it functions as an insulin sensitizer both peripherally and centrally. Similar to HN, the levels of circulating SHLP2 were found to decrease with age. These results suggest that mitochondria play critical roles in metabolism and survival through the synthesis of mitochondrial peptides, and provide new insights into mitochondrial biology with relevance to aging and human biology.

AIMS/HYPOTHESIS: Absent in melanoma 2 (AIM2) is a cytosolic sensor for double-stranded DNA and a tumour suppressor. Binding of double-stranded DNA to AIM2 forms the AIM2 inflammasome, leading to activation of caspase-1 and production of IL-1β and IL-18. Although inflammasome-independent effects of AIM2 have been reported, its role in energy metabolism is unknown. We aimed to evaluate the effect of AIM2 in energy metabolism and glucose homeostasis. METHODS: Male and female whole body Aim2 knockout (Aim2(−/−)) mice were used in the current study. Body weight, food intake, body composition, energy expenditure, fasting blood glucose levels, GTT and body temperature were measured at indicated time points. RNA sequencing was carried out on gonadal white adipose tissue (gWAT) in 14-month-old female mice. mRNA and protein levels in tissues were analysed by quantitative real-time PCR and immunoblot. Immune cell infiltration in gWAT was examined by flow cytometry. Stromal vascular fractions isolated from gWAT were used to investigate adipocyte differentiation. RESULTS: Male and female Aim2(−/−) mice were obese compared with wild-type controls from 7 weeks of age until 51 weeks of age, with increased adiposity in both subcutaneous and visceral fat depots. While there were no differences in food intake, Aim2(−/−) mice demonstrated decreased energy expenditure and impaired brown adipose tissue function compared with wild-type controls. Fasting glucose and insulin levels were elevated, and Aim2(−/−) mice were glucose intolerant on intraperitoneal GTT. RNA sequencing revealed marked upregulation of the IFN-inducible gene Ifi202b, which encodes protein 202 (p202) and elevated inflammatory signalling in gWAT of Aim2(−/−) mice. Increased infiltration of total and Ly6C(low) monocytes was noted at 8 weeks of age in gWAT, before the onset of obesity and insulin resistance. Ifi202b knockdown blocked adipogenesis in stromal vascular fractions and reduced inflammation in bone marrow-derived macrophages, demonstrating a key role of p202 in mediating the increased adipogenesis and inflammation in Aim2(−/−) mice. CONCLUSIONS/INTERPRETATION: These results demonstrate a fundamental role for AIM2 in energy metabolism, inflammation and insulin resistance. Our studies establish a novel link between the innate immunity proteins, AIM2 and p202, and metabolism.

Absent in Melanoma (AIM) 2, an HIN-200 domain family interferon inducible gene, is a cytosolic sensor for double-stranded DNA, forms the AIM2 inflammasome, and is a tumor suppressor gene. Lack of AIM2 increases the risk for cancers including liver cancer. We had earlier shown that mice with whole body deletion of AIM2 (AIM2-/-) exhibit increased body weight and total fat mass (without change in lean mass), visceral and subcutaneous adiposity, elevated fasting glucose and impaired glucose tolerant test without significant change in food intake. To assess the effects of AIM2-/- on liver, we analyzed liver weight, gene expression and protein levels of key players of hepatic lipid metabolism in female wild type (WT) and AIM2-/- mice (14-month-old, n=7/group) on chow diet. Fatty acid oxidation in liver was determined by incubating 14C-palmitate with liver lysate, and trapping and quantifying the 14CO2 generated from the 14C-palmitate. We found that liver was enlarged in AIM2-/- mice compared to WT controls (liver weight 1.25±0.03 vs. 1.62±0.09 g, p Disclosure Z. Gong: None. R. Jiang: None. K. Su: None. E. Goetzman: None. H. Dong: None. R. Muzumdar: None.

Secondary bacterial respiratory infections are commonly associated with both acute and chronic lung injury. Influenza complicated by bacterial pneumonia is an effective model to study host defense during pulmonary superinfection due to its clinical relevance. Multiprotein inflammasomes are responsible for IL-1β production in response to infection and drive tissue inflammation. In this study, we examined the role of the inflammasome during viral/bacterial superinfection. We demonstrate that ASC–/– mice are protected from bacterial superinfection and produce sufficient quantities of IL-1β through an apoptosis-associated speck-like protein containing CARD (ASC) inflammasome–independent mechanism. Despite the production of IL-1β by ASC–/– mice in response to bacterial superinfection, these mice display decreased lung inflammation. A neutrophil elastase inhibitor blocked ASC inflammasome–independent production of IL-1β and the IL-1 receptor antagonist, anakinra, confirmed that IL-1 remains crucial to the clearance of bacteria during superinfection. Delayed inhibition of NLRP3 during influenza infection by MCC950 decreases bacterial burden during superinfection and leads to decreased inflammatory cytokine production. Collectively, our results demonstrate that ASC augments the clearance of bacteria, but can also contribute to inflammation and mortality. ASC should be considered as a therapeutic target to decrease morbidity and mortality during bacterial superinfection.

β-Cell compensation is an essential mechanism by which β-cells increase insulin secretion for overcoming insulin resistance to maintain euglycemia in obesity. Failure of β-cells to compensate for insulin resistance contributes to insulin insufficiency and overt diabetes. To understand the mechanism of β-cell compensation, we characterized the role of forkhead box O1 (FoxO1) in β-cell compensation in mice under physiological and pathological conditions. FoxO1 is a key transcription factor that serves as a nutrient sensor for integrating insulin signaling to cell metabolism, growth, and proliferation. We showed that FoxO1 improved β-cell compensation via 3 distinct mechanisms by increasing β-cell mass, enhancing β-cell glucose sensing, and augmenting β-cell antioxidative function. These effects accounted for increased glucose-stimulated insulin secretion and enhanced glucose tolerance in β-cell-specific FoxO1-transgenic mice. When fed a high-fat diet, β-cell-specific FoxO1-transgenic mice were protected from developing fat-induced glucose disorder. This effect was attributable to increased β-cell mass and function. Furthermore, we showed that FoxO1 activity was up-regulated in islets, correlating with the induction of physiological β-cell compensation in high-fat-induced obese C57BL/6J mice. These data characterize FoxO1 as a pivotal factor for orchestrating physiological adaptation of β-cell mass and function to overnutrition and obesity.

Humanin (HN) is an endogenous mitochondria-associated peptide that has been shown to protect against various Alzheimer's disease-associated insults, myocardial ischemia-reperfusion injury, and reactive oxygen species-induced cell death. We have shown previously that HN improves whole body glucose homeostasis by improving insulin sensitivity and increasing glucose-stimulated insulin secretion (GSIS) from the β-cells. Here, we report that intraperitoneal treatment with one of HN analogs, HNG, decreases body weight gain, visceral fat, and hepatic triglyceride (TG) accumulation in high-fat diet-fed mice. The decrease in hepatic TG accumulation is due to increased activity of hepatic microsomal triglyceride transfer protein (MTTP) and increased hepatic TG secretion. Both intravenous (iv) and intracerebroventricular (icv) infusion of HNG acutely increase TG secretion from the liver. Vagotomy blocks the effect on both iv and icv HNG on TG secretion, suggesting that the effects of HNG on hepatic TG flux are centrally mediated. Our data suggest that HN is a new player in central regulation of peripheral lipid metabolism.

Inactivating FSH receptor (FSHR) mutations can affect ovarian function, resulting in variable clinical presentations ranging from primary amenorrhea to premature menopause. FSHR mutations have been largely reported in the Finnish population, but in patients of Asian Indian descent, the incidence of FSHR mutations is extremely rare.Two female siblings of Indian descent were diagnosed with primary ovarian failure and hypergonadotropic hypogonadism. The daughters were the result of a consanguineous marriage between second cousins. A combination of comparative genomic hybridization plus single nucleotide polymorphism array and whole exome sequencing was conducted on the family to identify potential causative genetic variants.Both daughters were found to have a novel pathogenic variant in FSHR (c.1253TG, p.Ile418Ser), inherited as an autosomal recessive trait from heterozygous parents. This loss of function mutation is located in exon 10 of FSHR affecting the second transmembrane helix of the FSHR protein. The transmembrane domain of FSHR is highly conserved across species and is involved in signal transduction. The FSHR c.1253TG variant is next to a known pathogenic variant, rs12190966 (c.1255GA, p.Ala419Thr), previously reported in a Finnish woman with primary amenorrhea.

Although obesity has been associated with asthma, body mass index is suboptimal to fully characterize adiposity.We examined the relation between adiposity and asthma in a large sample of the U.S. population, using indices defined by dual-energy X-ray absorptiometry.We analyzed data from 8,886 children (aged 8-19 yr) and 12,795 adults (aged 20-69 yr) from the 2001 to 2006 National Health and Nutrition Examination Survey. In addition to body mass index, percent body fat, waist circumference, and waist-to-height ratio, dual-energy X-ray absorptiometry was used to calculate whole-body and local adiposity indices: fat mass index; total, trunk, and legs percent fat; and trunk-to-total fat mass ratio, legs-to-total fat mass ratio, and trunk-to-legs fat mass ratios. Logistic regression was used for the analysis of adiposity measures and asthma.Among children, general adiposity was significantly associated with asthma, with no major differences by sex. Results were driven by nonatopic children, in whom trunk-predominant (central) adiposity (assessed by waist circumference, waist-to-height ratio, trunk-to-total fat mass ratio, and trunk-to-legs fat mass ratio) was also associated with asthma. There were no significant associations among atopic children. Among adults, all adiposity indices were associated with asthma, with central adiposity significant only among women. The results in adults were driven by atopy, especially in women.Adiposity measured by dual-energy X-ray absorptiometry provides similar information to that obtained by using anthropometric indices among children of both sexes and among adult men. However, dual-energy X-ray absorptiometry provides additional information in adult women, in whom dual-energy X-ray absorptiometry-measured central adiposity is significantly associated with asthma, particularly atopic asthma.

Research over the past two decades has led to advances in our understanding of the genetic and metabolic factors that underlie the pathogenesis of type 2 diabetes mellitus (T2DM). While T2DM is defined by its hallmark metabolic symptoms, the genetic risk factors for T2DM are more immune-related than metabolism-related, and the observed metabolic disease may be secondary to chronic inflammation. Regardless, these metabolic changes are not benign, as the accumulation of some metabolic intermediates serves to further drive the inflammation and cell stress, eventually leading to insulin resistance and ultimately to T2DM. Because many of the biochemical changes observed in the pre-diabetic state (i.e., ectopic lipid storage, increased acylcarnitines, increased branched-chain amino acids) are also observed in patients with rare inborn errors of fatty acid and amino acid metabolism, an interesting question is raised regarding whether isolated metabolic gene defects can confer an increased risk for T2DM. In this review, we attempt to address this question by summarizing the literature regarding the metabolic pathways at the crossroads of diabetes and inborn errors of metabolism. Studies using cell culture and animal models have revealed that, within a given pathway, disrupting some genes can lead to insulin resistance while for others there may be no effect or even improved insulin sensitivity. This differential response to ablating a single metabolic gene appears to be dependent upon the specific metabolic intermediates that accumulate and whether these intermediates subsequently activate inflammatory pathways. This highlights the need for future studies to determine whether certain inborn errors may confer increased risk for diabetes as the patients age.

Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyperglycemia, and insulin resistance. In addition, carbohydrate utilization as a fuel is substantially inhibited. Correction or reversal of these effects during high-fat diet (HFD) intake is of exceptional interest in light of widespread occurrence of diet-associated metabolic disorders in global human populations. Here we report that mangiferin (MGF), a natural compound (the predominant constituent of Mangifera indica extract from the plant that produces mango), protected against HFD-induced weight gain, increased aerobic mitochondrial capacity and thermogenesis, and improved glucose and insulin profiles. To obtain mechanistic insight into the basis for these effects, we determined that mice exposed to an HFD combined with MGF exhibited a substantial shift in respiratory quotient from fatty acid toward carbohydrate utilization. MGF treatment significantly increased glucose oxidation in muscle of HFD-fed mice without changing fatty acid oxidation. These results indicate that MGF redirects fuel utilization toward carbohydrates. In cultured C2C12 myotubes, MGF increased glucose and pyruvate oxidation and ATP production without affecting fatty acid oxidation, confirming in vivo and ex vivo effects. Furthermore, MGF inhibited anaerobic metabolism of pyruvate to lactate but enhanced pyruvate oxidation. A key target of MGF appears to be pyruvate dehydrogenase, determined to be activated by MGF in a variety of assays. These findings underscore the therapeutic potential of activation of carbohydrate utilization in correction of metabolic syndrome and highlight the potential of MGF to serve as a model compound that can elicit fuel-switching effects.

In lower or simple species, such as worms and flies, disruption of the insulin-like growth factor (IGF)-1 and the insulin signaling pathways has been shown to increase lifespan. In rodents, however, growth hormone (GH) regulates IGF-1 levels in serum and tissues and can modulate lifespan via/or independent of IGF-1. Rodent models, where the GH/IGF-1 axis was ablated congenitally, show increased lifespan. However, in contrast to rodents where serum IGF-1 levels are high throughout life, in humans, serum IGF-1 peaks during puberty and declines thereafter during aging. Thus, animal models with congenital disruption of the GH/IGF-1 axis are unable to clearly distinguish between developmental and age-related effects of GH/IGF-1 on health. To overcome this caveat, we developed an inducible liver IGF-1-deficient (iLID) mouse that allows temporal control of serum IGF-1. Deletion of liver Igf -1 gene at one year of age reduced serum IGF-1 by 70% and dramatically impaired health span of the iLID mice. Reductions in serum IGF-1 were coupled with increased GH levels and increased basal STAT5B phosphorylation in livers of iLID mice. These changes were associated with increased liver weight, increased liver inflammation, increased oxidative stress in liver and muscle, and increased incidence of hepatic tumors. Lastly, despite elevations in serum GH, low levels of serum IGF-1 from 1 year of age compromised skeletal integrity and accelerated bone loss. We conclude that an intact GH/IGF-1 axis is essential to maintain health span and that elevated GH, even late in life, associates with increased pathology.

Nonalcoholic fatty liver disease (NAFLD), characterized by excessive fat accumulation in liver, is prevalent in obesity. Genetic factors that link obesity to NAFLD remain obscure. Apolipoprotein C3 (APOC3) is a lipid-binding protein with a pivotal role in triglyceride metabolism. Humans with APOC3 gain-of-function mutations and mice with APOC3 overproduction are associated with hypertriglyceridemia. Nonetheless, it remains controversial whether APOC3 is culpable for diet-induced NAFLD. To address this fundamental issue, we fed APOC3-transgenic and wild-type littermates a high fructose diet or high fat diet, followed by determination of the effect of APOC3 on hepatic lipid metabolism and inflammation and the progression of NAFLD. To gain mechanistic insight into NAFLD, we determined the impact of APOC3 on hepatic triglyceride synthesis and secretion versus fatty acid oxidation. APOC3-transgenic mice were hypertriglyceridemic, culminating in marked elevation of triglycerides, cholesterols, and non-esterified fatty acids in plasma. Despite the prevailing hypertriglyceridemia, APOC3-transgenic mice, relative to wild-type littermates, had similar weight gain and hepatic lipid content without alterations in hepatic expression of key genes involved in triglyceride synthesis and secretion and fatty acid oxidation. APOC3-transgenic and wild-type mice had similar Kupffer cell content without alterations in hepatic expression of pro- and anti-inflammatory cytokines. APOC3 neither exacerbated diet-induced adiposity nor aggravated the degree of steatosis in high fructose or high fat-fed APOC3-transgenic mice. These effects ensued independently of weight gain even after 10-month high fat feeding. We concluded that APOC3, whose dysregulation is liable for hypertriglyceridemia, is not a predisposing factor for linking overnutrition to NAFLD in obesity.

Gong et al. show in multiple cell types that a mitochondrial-associate peptide, humanin, activates chaperone-mediated autophagy (CMA) by stabilizing the interaction between HSP90 and CMA substrates, thereby protecting cells from stressor-induced cell death., Chaperone-mediated autophagy (CMA) serves as quality control during stress conditions through selective degradation of cytosolic proteins in lysosomes. Humanin (HN) is a mitochondria-associated peptide that offers cytoprotective, cardioprotective, and neuroprotective effects in vivo and in vitro. In this study, we demonstrate that HN directly activates CMA by increasing substrate binding and translocation into lysosomes. The potent HN analogue HNG protects from stressor-induced cell death in fibroblasts, cardiomyoblasts, neuronal cells, and primary cardiomyocytes. The protective effects are lost in CMA-deficient cells, suggesting that they are mediated through the activation of CMA. We identified that a fraction of endogenous HN is present at the cytosolic side of the lysosomal membrane, where it interacts with heat shock protein 90 (HSP90) and stabilizes binding of this chaperone to CMA substrates as they bind to the membrane. Inhibition of HSP90 blocks the effect of HNG on substrate translocation and abolishes the cytoprotective effects. Our study provides a novel mechanism by which HN exerts its cardioprotective and neuroprotective effects.

Aging is associated with dysregulation of glucose and lipid metabolism. Various factors that contribute to the dysregulation include both modifiable (e.g. obesity, insulin resistance) and non-modifiable risk factors (age-associated physiologic changes). Although there is no linear relationship between aging and prevalence of non-alcoholic fatty liver disease, current data strongly suggests that advanced age leads to more severe histological changes and poorer clinical outcomes. Hepatic lipid accumulation could lead to significant hepatic and systemic consequences including steatohepatitis, cirrhosis, impairment of systemic glucose metabolism and metabolic syndrome, thereby contributing to age-related diseases. Insulin, leptin and adiponectin are key regulators of the various physiologic processes that regulate hepatic lipid metabolism. Recent advances have expanded our understanding in this field, highlighting the role of novel mediators such as FGF 21, and mitochondria derived peptides. In this review, we will summarize the mediators of hepatic lipid metabolism and how they are altered in aging.

IGF-I shares structural homology and in vitro metabolic activity with insulin. Laboratory models suggest that IGF-I and its binding proteins IGFBP-1 and IGFBP-2 have potentially beneficial effects on diabetes risk, whereas IGFBP-3 may have adverse effects. We therefore conducted a prospective nested case-control investigation of incident diabetes (n = 742 case subjects matched 1:1 to control subjects) and its associations with IGF-axis protein levels in the Nurses’ Health Study, a cohort of middle-aged women. The median time to diabetes was 9 years. Statistical analyses were adjusted for multiple risk factors, including insulin and C-reactive protein. Diabetes risk was fivefold lower among women with baseline IGFBP-2 levels in the top versus bottom quintile (odds ratio [OR]q5–q1 = 0.17 [95% CI 0.08–0.35]; P trend < 0.0001) and was also negatively associated with IGFBP-1 levels (ORq5–q1 = 0.37 [0.18–0.73]; P trend = 0.0009). IGFBP-3 was positively associated with diabetes (ORq5–q1 = 2.05 [1.20–3.51]; P trend = 0.002). Diabetes was not associated with total IGF-I levels, but free IGF-I and diabetes had a significant association that varied (P interaction = 0.003) by insulin levels above the median (ORq5–q1 = 0.48 [0.26–0.90]; P trend = 0.0001) versus below the median (ORq5–q1 = 2.52 [1.05–6.06]; P trend < 0.05). Thus, this prospective study found strong associations of incident diabetes with baseline levels of three IGFBPs and free IGF-I, consistent with hypotheses that the IGF axis might influence diabetes risk.

Objective— Humanin (HN), an endogenous antiapoptotic peptide, has previously been shown to protect against Alzheimer’s disease and a variety of cellular insults. We evaluated the effects of a potent analog of HN (HNG) in an in vivo murine model of myocardial ischemia and reperfusion. Methods and Results— Male C57BL6/J mice (8 to 10 week old) were subjected to 45 minutes of left coronary artery occlusion followed by a 24-hour reperfusion. HNG or vehicle was administered IP 1 hour prior or at the time of reperfusion. The extent of myocardial infarction per area-at-risk was evaluated at 24 hours using Evans Blue dye and 2-3-5-triphenyl tetrazolium chloride staining. Left ventricular function was evaluated at 1 week after ischemia using high-resolution, 2D echocardiography (VisualSonics Vevo 770). Myocardial cell signaling pathways and apoptotic markers were assessed at various time points (0 to 24 hours) following reperfusion. Cardiomyocyte survival and apoptosis in response to HNG were assessed in vitro. HNG reduced infarct size relative to the area-at-risk in a dose-dependent fashion, with a maximal reduction at the dose of 2 mg/kg. HNG therapy enhanced left ventricular ejection fraction and preserved postischemic left ventricular dimensions (end-diastolic and end-systolic), resulting in improved cardiac function. Treatment with HNG significantly increased phosphorylation of AMPK and phosphorylation of endothelial nitric oxide synthase in the heart and attenuated Bcl-2-associated X protein and B-cell lymphoma-2 levels following myocardial ischemia and reperfusion. HNG improved cardiomyocyte survival and decreased apoptosis in response to daunorubicin in vitro. Conclusion— These data show that HNG provides cardioprotection in a mouse model of myocardial ischemia and reperfusion potentially through activation of AMPK-endothelial nitric oxide synthase-mediated signaling and regulation of apoptotic factors. HNG may represent a novel agent for the treatment of acute myocardial infarction.

Assessing insulin resistance in rodent models gives insight into mechanisms that cause type 2 diabetes and the metabolic syndrome. The hyperinsulinemic euglycemic glucose clamp, the reference standard for measuring insulin sensitivity in humans and animals, is labor intensive and technically demanding. A number of simple surrogate indexes of insulin sensitivity/resistance have been developed and validated primarily for use in large human studies. These same surrogates are also frequently used in rodent studies. However, in general, these indexes have not been rigorously evaluated in animals. In a recent validation study in mice, we demonstrated that surrogates have a weaker correlation with glucose clamp estimates of insulin sensitivity/resistance than in humans. This may be due to increased technical difficulties in mice and/or intrinsic differences between human and rodent physiology. To help distinguish among these possibilities, in the present study, using data from rats substantially larger than mice, we compared the clamp glucose infusion rate (GIR) with surrogate indexes, including QUICKI, HOMA, 1/HOMA, log (HOMA), and 1/fasting insulin. All surrogates were modestly correlated with GIR ( r = 0.34–0.40). Calibration analyses of surrogates adjusted for body weight demonstrated similar predictive accuracy for GIR among all surrogates. We conclude that linear correlations of surrogate indexes with clamp estimates and predictive accuracy of surrogate indexes in rats are similar to those in mice (but not as substantial as in humans). This additional rat study (taken with the previous mouse study) suggests that application of surrogate insulin sensitivity indexes developed for humans may not be appropriate for determining primary outcomes in rodent studies due to intrinsic differences in metabolic physiology. However, use of surrogates may be appropriate in rodents, where feasibility of clamps is an obstacle and measurement of insulin sensitivity is a secondary outcome.

Insulin resistance (IR) is a hallmark of pregnancy. Because increased visceral fat (VF) is associated with IR in nonpregnant states, we reasoned that fat accretion might be important in the development of IR during pregnancy. To determine whether VF depots increase in pregnancy and whether VF contributes to IR, we studied three groups of 6-mo-old female Sprague-Dawley rats: 1) nonpregnant sham-operated rats (Nonpreg; n = 6), 2) pregnant sham-operated rats (Preg; n = 6), and 3) pregnant rats in which VF was surgically removed 1 mo before mating (PVF−; n = 6). VF doubled by day 19 of pregnancy (Nonpreg 5.1 ± 0.3, Preg 10.0 ± 1.0 g, P < 0.01), and PVF− had similar amounts of VF compared with Nonpreg (PVF− 4.6 ± 0.8 g). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp in late gestation in chronically catheterized unstressed rats. Glucose IR (mg·kg−1·min−1) was highest in Nonpreg (19.4 ± 2.0), lowest in Preg (11.1 ± 1.4), and intermediate in PVF− (14.7 ± 0.6; P < 0.001 between all groups). During the clamp, Nonpreg had greater hepatic insulin sensitivity than Preg [hepatic glucose production (HGP): Nonpreg 4.5 ± 1.3, Preg 9.3 ± 0.5 mg·kg−1·min−1; P < 0.001]. With decreased VF, hepatic insulin sensitivity was similar to nonpregnant levels in PVF− (HGP 4.9 ± 0.8 mg·kg−1·min−1). Both pregnant groups had lower peripheral glucose uptake compared with Nonpreg. In parallel with hepatic insulin sensitivity, hepatic triglyceride content was increased in pregnancy (Nonpreg 1.9 ± 0.4 vs. Preg 3.2 ± 0.3 mg/g) and decreased with removal of VF (PVF− 1.3 ± 0.4 mg/g; P < 0.05). Accretion of visceral fat is an important component in the development of hepatic IR in pregnancy, and accumulation of hepatic triglycerides is a mechanism by which visceral fat may modulate insulin action in pregnancy.

Insulin-like growth factor binding protein (IGFBP)-3 binds to IGF and modulates their actions and also possesses intrinsic activities. We investigated its effects on insulin action and found that when IGFBP-3 was added to fully differentiated 3T3-L1 adipocytes in culture, insulin-stimulated glucose transport was significantly inhibited to 60% of control in a time- and dose-dependent manner. Tumor necrosis factor (TNF)-alpha treatment also inhibited glucose transport to the same degree as IGFBP-3 and, in addition, increased IGFBP-3 levels 3-fold. Co-treatment with TNF-alpha and IGFBP-3 antisense partially prevented the inhibitory effect of TNF-alpha on glucose transport, indicating a role for IGFBP-3 in cytokine-induced insulin resistance. Insulin-stimulated phosphorylation of the insulin receptor was markedly decreased by IGFBP-3 treatment. IGFBP-3 treatment suppressed adiponectin expression in 3T3-L1 adipocytes. Infusion of IGFBP-3 to Sprague-Dawley rats for 3 h decreased peripheral glucose uptake by 15% compared with controls as well as inhibiting glycogen synthesis. Systemic administration of IGFBP-3 to rats for 7 d resulted in a dramatic 40% decrease in peripheral glucose utilization and glycogen synthesis. These in vitro and in vivo findings demonstrate that IGFBP-3 has potent insulin-antagonizing capability and suggest a role for IGFBP-3 in cytokine-induced insulin resistance and other mechanisms involved in the development of type-2 diabetes.

Iodide (I(-)), an essential constituent of the thyroid hormones, is actively accumulated in the thyroid by the Na(+)/I(-) symporter (NIS), a key plasma membrane protein encoded by the slc5a5 gene. Mutations in slc5a5 cause I(-) transport defects (ITDs), autosomal-recessive disorders in which I(-) accumulation is totally or partially impaired, leading to congenital hypothyroidism. The characterization of NIS mutants has yielded significant insights into the molecular mechanism of NIS.This study aimed to determine the basis of a patient's ITD clinical phenotype, by sequencing her slc5a5 gene.Genomic DNA was purified and the slc5a5 gene sequence determined. Functional in vitro studies were performed to characterize the V270E NIS mutant.The index patient was diagnosed with hypothyroidism with minimal radioiodide uptake in a normally located, although enlarged, thyroid gland.We identified a new NIS mutation: V270E. The patient had the compound heterozygous NIS mutation R124H/V270E. R124H NIS has been characterized previously. We show that V270E markedly reduces I(-) uptake via a pronounced (but not total) impairment of the protein's plasma membrane targeting. Remarkably, V270E is intrinsically active. Therefore, a negative charge at position 270 interferes with NIS cell surface trafficking. The patient's minimal I(-) uptake enabled sufficient thyroid hormone biosynthesis to prevent cognitive impairment.A nonpolar residue at position 270, which all members of the SLC5A family have, is required for NIS plasma membrane targeting.

Impairment of both insulin and leptin action has been implicated in the pathogenesis of nonalcoholic fatty liver disease. By assessing hepatic triglyceride (TG) stores in response to modulation of leptin action (by leptin infusion), we attempted to determine whether leptin has the major role in hepatic TG accumulation. TG were markedly decreased (by 63%, P

IGF-I is recognized as an insulin sensitizer at the liver and muscle, while recent evidence suggests that IGF-binding protein (IGFBP)-3 acts as an insulin antagonist. As there is a paucity of IGF-I receptors in the liver and as the IGF-IGFBP system in the central nervous system is emerging as physiologically relevant, we examined whether the effects of IGF-I and IGFBP-3 on insulin action are mediated through central mechanisms. Intracerebroventricular (ICV) infusion of IGF-I during the insulin clamp (3 mU · kg−1 · min−1) resulted in significant improvement in hepatic insulin action (50%, P < 0.05). In contrast, ICV infusion of IGFBP-3 significantly impaired insulin action at the liver (45% increase in hepatic glucose production, P < 0.01). While IGF-I marginally increased peripheral glucose uptake, IGFBP-3 significantly decreased peripheral glucose uptake (∼30%, P < 0.01). As the nuclear localization signal mutant IGFBP-3, which has a normal affinity to IGFs but binds other IGFBP-3 partners poorly and fails to normally internalize, has reduced central activity on metabolism, we conclude that the effects of IGFBP-3 on the hypothalamus involve activity mediated by interfacing with other molecules in addition to IGFs. Marked, opposing, and independent physiological effects of IGF-I and IGFBP-3 through central mechanisms may have implications on potential strategies in specific modulation of peripheral insulin action.

Obstructive sleep apnea (OSA) is a highly prevalent medical condition in obese children and is associated with significant neurocognitive, cardiovascular and metabolic derangements. Monogenic forms of obesity resulting from disruption of the leptin-melanocortin pathways have become more notable in recent years and distinguish between various obese phenotypes. However, the association of such disorders with OSA is not well established in children or adults. In this report, we describe a 23-month-old female with morbid obesity and OSA, who was found to carry a defect in the melanocortin-4 receptor (MC4R) pathway. This report emphasizes the genetic basis of obesity related to MC4R deficiency and OSA in children.