STEMIN and YAP5SA synthetic modified mRNAs regenerate and repair infarcted mouse hearts.

Introduction: The adult heart lacks the regenerative capacity to self-repair. Serum response factor (SRF) is essential for heart organogenesis, sarcomerogenesis, and contractility. SRF interacts with co-factors, such as NKX2.5 and GATA4, required for cardiac specified gene activity. ETS factors such as ELK1 interact with SRF and drive cell replication. To weaken SRF interactions with NKX2.5 and GATA4, one mutant, SRF153(A3) named STEMIN, did not bind CArG boxes, yet induced stem cell factors such as NANOG and OCT4, cardiomyocyte dedifferentiation, and cell cycle reentry. The mutant YAP5SA of the Hippo pathway also promotes cardiomyocyte proliferation and growth. Aim: Infarcted adult mouse hearts were injected with translatable STEMIN and YAP5SA mmRNA to evaluate their clinical potential. Methods and Results: Mice were pulsed one day later with alpha-EDU and then heart sections were DAPI stained. Replicating cells were identified by immuno-staining against members of the DNA replisome pathway that mark entry to S phase of the cell cycle. Echocardiography was used to determine cardiac function following infarcts and mRNA treatment. To monitor cardiac wall repair, microscopic analysis was performed, and the extent of myocardial fibrosis was analyzed for immune cell infiltration. Injections of STEMIN and YAP5SA mmRNA into the left ventricles of infarcted adult mice promoted a greater than 17-fold increase in the DAPI stained and alpha-EDU marked cardiomyocyte nuclei, within a day. We observed de novo expression of phospho-histone H3, ORC2, MCM2, and CLASPIN. Cardiac function was significantly improved by four weeks post-infarct, and fibrosis and immune cell infiltration were diminished in hearts treated with STEMIN and YAP5SA mmRNA than each alone. Conclusion: STEMIN and YAP5SA mmRNA improved cardiac function and myocardial fibrosis in left ventricles of infarcted adult mice. The combinatorial use of mmRNA encoding STEMIN and YAP5SA has the potential to become a powerful clinical strategy to treat human heart disease.

HIV-1 Viral Protein R Couples Metabolic Inflexibility With White Adipose Tissue Thermogenesis.

Persons living with HIV (PLWH) manifest chronic disorders of brown and white adipose tissues that lead to diabetes and metabolic syndrome. The mechanisms that link viral factors to defective adipose tissue function and abnormal energy balance in PLWH remain incompletely understood. Here, we explored how the HIV accessory protein viral protein R (Vpr) contributes to adaptive thermogenesis in two mouse models and human adipose tissues. Uncoupling protein 1 (UCP1) gene expression was strongly increased in subcutaneous white adipose tissue (WAT) biopsy specimens from PLWH and in subcutaneous WAT of the Vpr mice, with nearly equivalent mRNA copy number. Histology and functional studies confirmed beige transformation in subcutaneous but not visceral WAT in the Vpr mice. Measurements of energy balance indicated Vpr mice displayed metabolic inflexibility and could not shift efficiently from carbohydrate to fat metabolism during day-night cycles. Furthermore, Vpr mice showed a marked inability to defend body temperature when exposed to 4°C. Importantly, Vpr couples higher tissue catecholamine levels with UCP1 expression independent of ß-adrenergic receptors. Our data reveal surprising deficits of adaptive thermogenesis that drive metabolic inefficiency in HIV-1 Vpr mouse models, providing an expanded role for viral factors in the pathogenesis of metabolic disorders in PLWH.

Conversion of human cardiac progenitor cells into cardiac pacemaker-like cells.

We used a screening strategy to test for reprogramming factors for the conversion of human cardiac progenitor cells (CPCs) into Pacemaker-like cells. Human transcription factors SHOX2, TBX3, TBX5, TBX18, and the channel protein HCN2, were transiently induced as single factors and in trio combinations into CPCs, first transduced with the connexin 30.2 (CX30.2) mCherry reporter. Following screens for reporter CX30.2 mCherry gene activation and FACS enrichment, we observed the definitive expression of many pacemaker specific genes; including, CX30.2, KCNN4, HCN4, HCN3, HCN1, and SCN3b. These findings suggest that the SHOX2, HCN2, and TBX5 (SHT5) combination of transcription factors is a much better candidate in driving the CPCs into Pacemaker-like cells than other combinations and single transcription factors. Additionally, single-cell RNA sequencing of SHT5 mCherry+ cells revealed cellular enrichment of pacemaker specific genes including TBX3, KCNN4, CX30.2, and BMP2, as well as pacemaker specific potassium and calcium channels (KCND2, KCNK2, and CACNB1). In addition, similar to human and mouse sinoatrial node (SAN) studies, we also observed the down-regulation of NKX2.5. Patch-clamp recordings of the converted Pacemaker-like cells exhibited HCN currents demonstrated the functional characteristic of pacemaker cells. These studies will facilitate the development of an optimal Pacemaker-like cell-based therapy within failing hearts through the recovery of SAN dysfunction.

ß-Adrenergic stimuli and rotating suspension culture enhance conversion of human adipogenic mesenchymal stem cells into highly conductive cardiac progenitors.

Clinical trials using human adipogenic mesenchymal stem cells (hAdMSCs) for the treatment of cardiac diseases have shown improvement in cardiac function and were proven safe. However, hAdMSCs do not convert efficiently into cardiomyocytes (CMs) or vasculature. Thus, reprogramming hAdMSCs into myocyte progenitors may fare better in future investigations. To reprogramme hAdMSCs into electrically conductive cardiac progenitor cells, we pioneered a three-step reprogramming strategy that uses proven MESP1/ETS2 transcription factors, ß-adrenergic and hypoxic signalling induced in three-dimensional (3D) cardiospheres. In Stage 1, ETS2 and MESP1 activated NNKX2.5, TBX5, MEF2C, dHAND, and GATA4 during the conversion of hAdMSCs into cardiac progenitor cells. Next, in Stage 2, ß2AR activation repositioned cardiac progenitors into de novo immature conductive cardiac cells, along with the appearance of RYR2, CAV2.1, CAV3.1, NAV1.5, SERCA2, and CX45 gene transcripts and displayed action potentials. In Stage 3, electrical conduction that was fostered by 3D cardiospheres formed in a Synthecon®, Inc. rotating bioreactor induced the appearance of hypoxic genes: HIF-1α/ß, PCG 1α/ß, and NOS2, which coincided with the robust activation of adult contractile genes including MLC2v, TNNT2, and TNNI3, ion channel genes, and the appearance of hyperpolarization-activated and cyclic nucleotide-gated channels (HCN1-4). Conduction velocities doubled to ~200 mm/s after hypoxia and doubled yet again after dissociation of the 3D cell clusters to ~400 mm/s. By comparison, normal conduction velocities within working ventricular myocytes in the whole heart range from 0.5 to 1 m/s. Epinephrine stimulation of stage 3 cardiac cells in patches resulted in an increase in amplitude of the electrical wave, indicative of conductive cardiac cells. Our efficient protocol that converted hAdMSCs into highly conductive cardiac progenitors demonstrated the potential utilization of stage 3 cells for tissue engineering applications for cardiac repair.

Arginine Metabolism Is Altered in Adults with A-ß + Ketosis-Prone Diabetes.

Background: A-ß + ketosis-prone diabetes (KPD) is a subset of type 2 diabetes in which patients have severe but reversible ß cell dysfunction of unknown etiology. Plasma metabolomic analysis indicates that abnormal arginine metabolism may be involved. Objective: The objective of this study was to determine the relation between gut microbiome and arginine metabolism and the relation between arginine availability and ß cell function in KPD patients compared with control participants. Methods: Kinetics of arginine and related metabolites were measured with stable isotope tracers, and insulin secretory responses to arginine and glucose were determined under euglycemic and hyperglycemic conditions in 6 KPD patients and 6 age-, gender-, and body mass index-matched control participants. Glucose potentiation of arginine-induced insulin secretion was performed in a different set of 6 KPD and 3 control participants. Results: Arginine availability was higher in KPD patients during euglycemia [53.5 ± 4.3 (mean ± SEM) compared with 40.3 ± 2.4 µmol · kg lean body mass (LBM)-1 · h-1, P = 0.03] but declined more in response to hyperglycemia (Δ 10.15 ± 2.6 compared with Δ 3.20 ± 1.3 µmol · kg LBM-1 · h-1, P = 0.041). During hyperglycemia, ornithine flux was not different between groups but after an arginine bolus, plasma ornithine AUC trended higher in KPD patients (3360 ± 294 compared with 2584 ± 259 min · µmol · L-1, P = 0.08). In both euglycemia and hyperglycemia, the first-phase insulin responses to glucose stimulation were lower in KPD patients (euglycemic insulin AUC 282 ± 108 compared with 926 ± 257 min · µU · mL-1, P = 0.02; hyperglycemic insulin AUC 358 ± 79 compared with 866 ± 292 min · µU · mL-1, P = 0.05), but exogenous arginine restored first-phase insulin secretion in KPD patients to the level of control participants. Conclusion: Compared with control participants, KPD patients have increased arginine availability in the euglycemic state, indicating a higher requirement. This is compromised during hyperglycemia, with an inadequate supply of arginine to sustain metabolic functions such as insulin secretion. Exogenous arginine administration restores a normal insulin secretory response.

HIV-1 viral protein R (Vpr) induces fatty liver in mice via LXRα and PPARα dysregulation: implications for HIV-specific pathogenesis of NAFLD.

HIV patients develop hepatic steatosis. We investigated hepatic steatosis in transgenic mice expressing the HIV-1 accessory protein Vpr (Vpr-Tg) in liver and adipose tissues, and WT mice infused with synthetic Vpr. Vpr-Tg mice developed increased liver triglyceride content and elevated ALT, bilirubin and alkaline phosphatase due to three hepatic defects: 1.6-fold accelerated de novo lipogenesis (DNL), 45% slower fatty acid ß-oxidation, and 40% decreased VLDL-triglyceride export. Accelerated hepatic DNL was due to coactivation by Vpr of liver X receptor-α (LXRα) with increased expression of its lipogenic targets Srebp1c, Chrebp, Lpk, Dgat, Fasn and Scd1, and intranuclear SREBP1c and ChREBP. Vpr enhanced association of LXRα with Lxrα and Srebp1c promoters, increased LXRE-LXRα binding, and broadly altered hepatic expression of LXRα-regulated lipid metabolic genes. Diminished hepatic fatty acid ß-oxidation was associated with decreased mRNA expression of Pparα and its targets Cpt1, Aox, Lcad, Ehhadh, Hsd10 and Acaa2, and blunted VLDL export with decreased expression of Mttp and its product microsomal triglyceride transfer protein. With our previous findings that Vpr circulates in HIV patients (including those with undetectable plasma HIV-1 RNA), co-regulates the glucocorticoid receptor and PPARγ and transduces hepatocytes, these data indicate a potential role for Vpr in HIV-associated fatty liver disease.

Factors associated with early relapse to insulin dependence in unprovoked A-ß+ ketosis-prone diabetes.

OBJECTIVE: Unprovoked "A-ß+" Ketosis-Prone Diabetes (KPD), a unique diabetic syndrome of adult-onset, obesity and proneness to ketoacidosis, is associated with rapid recovery of ß cell function and insulin-independence. Whereas most patients experience prolonged remission, a subset relapses early to insulin dependence. We sought to define factors associated with early relapse. METHODS: We utilized a prospective, longitudinal database to analyze 50 unprovoked A-ß+ KPD patients with >2 measurements of ß cell function and glycemia following baseline assessment. RESULTS: 19 patients (38%) relapsed to insulin dependence <1 year after the index DKA episode, while 31 (62%) remained insulin-independent for >1 year (median 4.2 years). Younger age at baseline (OR=0.947, P=0.033), and lower HOMA2-%ß (OR=0.982, P=0.001), lower HOMA2-IR (OR=0.582, P=0.046) and higher HbA1c at 1 year (OR=1.71, P=0.002) were associated with early relapse. A multivariate model with these variables and the interaction of HOMA2-%ß and HbA1c at 1 year provided a good fit (P<0.05). CONCLUSIONS: Relapse to insulin dependence in unprovoked A-ß+ KPD patients is associated with younger age and, after 1 year, lack of robust increase in ß cell functional reserve, and suboptimal glycemic control. Measurements of these parameters 1 year after the index DKA episode can be used to assess the need for insulin therapy.

Human adipose tissue as a reservoir for memory CD4+ T cells and HIV.

OBJECTIVE: The objective of this study is to determine whether adipose tissue functions as a reservoir for HIV-1. DESIGN: We examined memory CD4(+) T cells and HIV DNA in adipose tissue-stromal vascular fraction (AT-SVF) of five patients [four antiretroviral therapy (ART)-treated and one untreated]. To determine whether adipocytes stimulate CD4(+) T cells and regulate HIV production, primary human adipose cells were cocultured with HIV-infected CD4(+) T cells. METHODS: AT-SVF T cells were studied by flow cytometry, and AT-SVF HIV DNA (Gag and Env) was examined by nested PCR and sequence analyses. CD4(+) T-cell activation and HIV production were measured by flow cytometry and ELISA. RESULTS: AT-SVF CD3(+) T cells were activated (>60% CD69(+)) memory CD4(+) and CD8(+) T cells in uninfected and HIV-infected persons, but the AT-SVF CD4(+)/CD8(+) ratio was lower in HIV patients. HIV DNA (Gag and Env) was detected in AT-SVF of all five patients examined by nested PCR, comparably to other tissues [peripheral blood mononuclear cell (PBMC), lymph node or thymus]. In coculture experiments, adipocytes increased CD4(+) T-cell activation and HIV production approximately two to three-fold in synergy with gamma-chain cytokines interleukin (IL)-2, IL7 or IL15. These effects were mitigated by neutralizing antibodies against IL6 and integrin-α1ß1. Adipocytes also enhanced T-cell viability. CONCLUSION: Adipose tissues of ART-treated patients harbour activated memory CD4(+) T cells and HIV DNA. Adipocytes promote CD4(+) T-cell activation and HIV production in concert with intrinsic adipose factors. Adipose tissue may be an important reservoir for HIV.

Association of TCF7L2 variation with single islet autoantibody expression in children with type 1 diabetes.

BACKGROUND: The transcription factor 7-like 2 (TCF7L2) gene has the strongest genetic association with type 2 diabetes. TCF7L2 also associates with latent autoimmune diabetes in adults, which often presents with a single islet autoantibody, but not with classical type 1 diabetes. METHODS: We aimed to test if TCF7L2 is associated with single islet autoantibody expression in pediatric type 1 diabetes. We studied 71 prospectively recruited children who had newly diagnosed type 1 diabetes and evidence of islet autoimmunity, that is, expressed ≥1 islet autoantibody to insulin, glutamic acid decarboxylase 65, islet cell autoantigen 512, or zinc transporter 8. TCF7L2 rs7903146 alleles were identified. Data at diagnosis were cross-sectionally analyzed. RESULTS: We found that 21.1% of the children with autoimmune type 1 diabetes expressed a single islet autoantibody. The distribution of TCF7L2 rs7903146 genotypes in children with a single autoantibody (n=15) was 40% CC, 26.7% CT and 33.3% TT, compared with children with ≥2 islet autoantibodies (50% CC, 42.9% CT and 7.1% TT, p=0.024). Furthermore, compared with children with ≥2 autoantibodies, single-autoantibody children had characteristics reflecting milder autoimmune destruction of ß-cells. Restricting to lean children (body mass index<85th centile; n=36), 45.5% of those expressing a single autoantibody were rs7903146 TT homozygotes, compared with 0% of those with ≥2 autoantibodies (p<0.0001). CONCLUSION: These results suggest that, in children with only mild islet autoimmunity, mechanisms associated with TCF7L2 genetic variation contribute to diabetogenesis, and this contribution is larger in the absence of obesity.

Masked and overt autoantibodies specific to the DPD epitope of 65-kDa glutamate decarboxylase (GAD65-DPD) are associated with preserved ß-cell functional reserve in ketosis-prone diabetes.

CONTEXT: Ketosis-prone diabetes (KPD), defined by presentation with diabetic ketoacidosis (DKA), comprises 4 subgroups based on the presence or absence of islet cell autoantibodies (A(-) or A(+)) and ß-cell functional reserve (ß(-) or ß(+)). Among A(+) KPD, autoantibody epitope reactivity to 65-kDa glutamate decarboxylase (GAD65), defined by monoclonal GAD65Ab(DPD), was associated with greater ß-cell functional reserve. In a majority of healthy individuals, GAD65Ab are present in the sera but are masked by anti-idiotypic antibodies; in contrast, overtly GAD65Ab-positive patients with autoimmune type 1 diabetes patients lack these anti-idiotypic antibodies. OBJECTIVE: Our objective was to determine the presence of masked and overt GAD65Ab(DPD) in relation to ß-cell function and genetic risk factors in KPD patients. DESIGN: We investigated the associations of masked and overt GAD65Ab(DPD) with ß-cell functional reserve, and their relationship with human leukocyte antigen (HLA) class II haplotypes linked to autoimmune diabetes susceptibility or resistance, in a large KPD cohort. PATIENTS: Adult KPD patients (n = 384) were followed longitudinally in a research clinic. MAIN OUTCOME MEASURES: ß-Cell function, autoantibody status, GAD65Ab epitopes, and HLA class II haplotypes were evaluated. RESULTS: Overall, KPD patients with ß-cell functional reserve (ß(+) subgroups) showed significantly higher frequency of masked GAD65Ab(DPD) than patients without ß-cell functional reserve (ß(-) subgroups): 112 of 144 (79%) compared with 59 of 100 (59%), respectively (P = .002). Masked or overt GAD65Ab(DPD) were also more frequent among autoantibody-positive patients with preserved ß-cell functional reserve (A(+)ß(+) KPD) than those lacking ß-cell function (A(+)ß(-) KPD): 77% compared with 55% (P = .01). The susceptibility HLA haplotypes DQA1*0301/DQB1*0302 and DQA1*0301/DQB1*0201 were associated with absence of overt or masked GAD65Ab(DPD) (odds Ratios 2.3 and 2.2, respectively). CONCLUSIONS: Masked GAD65Ab(DPD) are strongly associated with preserved ß-cell functional reserve among patients with KPD. Absence of GAD65Ab(DPD) reactivity is associated with 2 HLA class II susceptibility haplotypes for autoimmune type 1 diabetes.

HIV-1 Vpr induces adipose dysfunction in vivo through reciprocal effects on PPAR/GR co-regulation.

Viral infections, such as HIV, have been linked to obesity, but mechanistic evidence that they cause adipose dysfunction in vivo is lacking. We investigated a pathogenic role for the HIV-1 accessory protein viral protein R (Vpr), which can coactivate the glucocorticoid receptor (GR) and co-repress peroxisome proliferator-activated receptor γ (PPARγ) in vitro, in HIV-associated adipose dysfunction. Vpr circulated in the blood of most HIV-infected patients tested, including those on antiretroviral therapy (ART) with undetectable viral load. Vpr-mediated mechanisms were dissected in vivo using mouse models expressing the Vpr transgene in adipose tissues and liver (Vpr-Tg) or infused with synthetic Vpr. Both models demonstrated accelerated whole-body lipolysis, hyperglycemia and hypertriglyceridemia, and tissue-specific findings. Fat depots in these mice had diminished mass, macrophage infiltration, and blunted PPARγ target gene expression but increased GR target gene expression. In liver, we observed blunted PPARα target gene expression, steatosis with decreased adenosine monophosphate-activated protein kinase activity, and insulin resistance. Similar to human HIV-infected patients, Vpr circulated in the serum of Vpr-Tg mice. Vpr blocked differentiation in preadipocytes through cell cycle arrest, whereas in mature adipocytes, it increased lipolysis with reciprocally altered association of PPARγ and GR with their target promoters. These results delineate a distinct pathogenic sequence: Vpr, released from HIV-1 in tissue reservoirs after ART, can disrupt PPAR/GR co-regulation and cell cycle control to produce adipose dysfunction and hepatosteatosis. Confirmation of these mechanisms in HIV patients could lead to targeted treatment of the metabolic complications with Vpr inhibitors, GR antagonists, or PPARγ/PPARα agonists.

Islet-specific T-cell responses and proinflammatory monocytes define subtypes of autoantibody-negative ketosis-prone diabetes.

OBJECTIVE: Ketosis-prone diabetes (KPD) is characterized by diabetic ketoacidosis (DKA) in patients lacking typical features of type 1 diabetes. A validated classification scheme for KPD includes two autoantibody-negative ("A-") phenotypic forms: "A-ß-" (lean, early onset, lacking ß-cell functional reserve) and "A-ß+" (obese, late onset, with substantial ß-cell functional reserve after the index episode of DKA). Recent longitudinal analysis of a large KPD cohort revealed that the A-ß+ phenotype includes two distinct subtypes distinguished by the index DKA episode having a defined precipitant ("provoked," with progressive ß-cell function loss over time) or no precipitant ("unprovoked," with sustained ß-cell functional reserve). These three A- KPD subtypes are characterized by absence of humoral islet autoimmune markers, but a role for cellular islet autoimmunity is unknown. RESEARCH DESIGN AND METHODS: Islet-specific T-cell responses and the percentage of proinflammatory (CD14+CD16+) blood monocytes were measured in A-ß- (n = 7), provoked A-ß+ (n = 15), and unprovoked A-ß+ (n = 13) KPD patients. Genotyping was performed for type 1 diabetes-associated HLA class II alleles. RESULTS: Provoked A-ß+ and A-ß- KPD patients manifested stronger islet-specific T-cell responses (P < 0.03) and higher percentages of proinflammatory CD14+CD16+ monocytes (P < 0.01) than unprovoked A-ß+ KPD patients. A significant relationship between type 1 diabetes HLA class II protective alleles and negative T-cell responses was observed. CONCLUSIONS: Provoked A-ß+ KPD and A-ß- KPD are associated with a high frequency of cellular islet autoimmunity and proinflammatory monocyte populations. In contrast, unprovoked A-ß+ KPD lacks both humoral and cellular islet autoimmunity.

Impaired lipoprotein processing in HIV patients on antiretroviral therapy: aberrant high-density lipoprotein lipids, stability, and function.

OBJECTIVE: HIV patients on antiretroviral therapy (HIV/ART) exhibit a unique atherogenic dyslipidemic profile with hypertriglyceridemia (HTG) and low plasma concentrations of high-density lipoprotein (HDL) cholesterol. In the Heart Positive Study of HIV/ART patients, a hypolipidemic therapy of fenofibrate, niacin, diet, and exercise reduced HTG and plasma non-HDL cholesterol concentrations and raised plasma HDL cholesterol and adiponectin concentrations. We tested the hypothesis that HIV/ART HDL have abnormal structures and properties and are dysfunctional. APPROACH AND RESULTS: Hypolipidemic therapy reduced the TG contents of low-density lipoprotein and HDL. At baseline, HIV/ART low-density lipoproteins were more triglyceride (TG)-rich and HDL were more TG- and cholesteryl ester-rich than the corresponding lipoproteins from normolipidemic (NL) subjects. Very-low-density lipoproteins, low-density lipoprotein, and HDL were larger than the corresponding lipoproteins from NL subjects; HIV/ART HDL were less stable than NL HDL. HDL-[(3)H]cholesteryl ester uptake by Huh7 hepatocytes was used to assess HDL functionality. HIV/ART plasma were found to contain significantly less competitive inhibition activity for hepatocyte HDL-cholesteryl ester uptake than NL plasma were found to contain (P<0.001). CONCLUSIONS: Compared with NL subjects, lipoproteins from HIV/ART patients are larger and more neutral lipid-rich, and their HDL are less stable and less receptor-competent. On the basis of this work and previous studies of lipase activity in HIV, we present a model in which plasma lipolytic activities or hepatic cholesteryl ester uptake are impaired in HIV/ART patients. These findings provide a rationale to determine whether the distinctive lipoprotein structure, properties, and function of HIV/ART HDL predict atherosclerosis as assessed by carotid artery intimal medial thickness.

Pathogenesis of A⁻ß⁺ ketosis-prone diabetes.

A⁻ß⁺ ketosis-prone diabetes (KPD) is an emerging syndrome of obesity, unprovoked ketoacidosis, reversible ß-cell dysfunction, and near-normoglycemic remission. We combined metabolomics with targeted kinetic measurements to investigate its pathophysiology. Fasting plasma fatty acids, acylcarnitines, and amino acids were quantified in 20 KPD patients compared with 19 nondiabetic control subjects. Unique signatures in KPD--higher glutamate but lower glutamine and citrulline concentrations, increased ß-hydroxybutyryl-carnitine, decreased isovaleryl-carnitine (a leucine catabolite), and decreased tricarboxylic acid (TCA) cycle intermediates--generated hypotheses that were tested through stable isotope/mass spectrometry protocols in nine new-onset, stable KPD patients compared with seven nondiabetic control subjects. Free fatty acid flux and acetyl CoA flux and oxidation were similar, but KPD had slower acetyl CoA conversion to ß-hydroxybutyrate; higher fasting ß-hydroxybutyrate concentration; slower ß-hydroxybutyrate oxidation; faster leucine oxidative decarboxylation; accelerated glutamine conversion to glutamate without increase in glutamate carbon oxidation; and slower citrulline flux, with diminished glutamine amide-nitrogen transfer to citrulline. The confluence of metabolomic and kinetic data indicate a distinctive pathogenic sequence: impaired ketone oxidation and fatty acid utilization for energy, leading to accelerated leucine catabolism and transamination of α-ketoglutarate to glutamate, with impaired TCA anaplerosis of glutamate carbon. They highlight a novel process of defective energy production and ketosis in A⁻ß⁺ KPD.

Transcription factors ETS2 and MESP1 transdifferentiate human dermal fibroblasts into cardiac progenitors.

Unique insights for the reprograming of cell lineages have come from embryonic development in the ascidian Ciona, which is dependent upon the transcription factors Ci-ets1/2 and Ci-mesp to generate cardiac progenitors. We tested the idea that mammalian v-ets erythroblastosis virus E26 oncogene homolog 2 (ETS2) and mesoderm posterior (MESP) homolog may be used to convert human dermal fibroblasts into cardiac progenitors. Here we show that murine ETS2 has a critical role in directing cardiac progenitors during cardiopoiesis in embryonic stem cells. We then use lentivirus-mediated forced expression of human ETS2 to convert normal human dermal fibroblasts into replicative cells expressing the cardiac mesoderm marker KDR(+). However, although neither ETS2 nor the purported cardiac master regulator MESP1 can by themselves generate cardiac progenitors de novo from fibroblasts, forced coexpression of ETS2 and MESP1 or cell treatment with purified proteins reprograms fibroblasts into cardiac progenitors, as shown by the de novo appearance of core cardiac transcription factors, Ca(2+) transients, and sarcomeres. Our data indicate that ETS2 and MESP1 play important roles in a genetic network that governs cardiopoiesis.

Leptin replacement therapy does not improve the abnormal lipid kinetics of hypoleptinemic patients with HIV-associated lipodystrophy syndrome.

Patients with HIV-associated dyslipidemic lipodystrophy (HADL) have characteristic lipid kinetic defects: accelerated lipolysis, blunted fat oxidation and increased hepatic fatty acid reesterification. HADL patients with lipoatrophy also have leptin deficiency. Small or non-randomized studies have suggested that leptin replacement improves glucose metabolism in HADL, with very limited data regarding its effects on the lipid kinetic abnormalities. We performed a randomized, double-blind, placebo-controlled, dose-escalating (0.02 mg/kg/d for two months; 0.04 mg/kg/d for a further two months) study of the effects of metreleptin on lipid kinetics in 17 adults with HADL, hypertriglyceridemia and hypoleptinemia. Rates of lipolysis, intra-adipocyte and intrahepatic reesterification and fatty acid oxidation were measured using infusions of (13)C(1)-palmitate and (2)H(5)-glycerol, and indirect calorimetry. Fasting lipid profiles and glucose and insulin responses to oral glucose challenge were also measured. Metreleptin treatment induced significant, dose-dependent increases in fasting plasma leptin levels. There was no significant change in total lipolysis, net lipolysis, adipocyte or hepatic re-esterification or fatty acid oxidation, or in fasting triglyceride or HDL-C concentrations, with metreleptin treatment. Metreleptin decreased fasting non-HDL-C levels (P<.01) and area-under-the-curve for glucose (P<.05). In hypoleptinemic HADL patients, treatment with metreleptin at 0.02 or 0.04 mg/kg/d does not improve abnormal fasting lipid kinetics, or triglyceride or HDL-C levels. Metreleptin does, however, improve glycemia and non-HDL-C in these patients. These results suggest a dissociation between leptin's effects on glucose metabolism compared to those on lipid kinetics in HADL.

Human monocytes accelerate proliferation and blunt differentiation of preadipocytes in association with suppression of C/EBPΑ mRNA.

Obesity, type 2 diabetes, and HIV-associated lipodystrophy are associated with abnormalities in adipocyte growth and differentiation. In persons with these conditions, adipose depots contain increased numbers of macrophages, but the origins of these cells and their specific effects are uncertain. Peripheral blood mononuclear cells (PBMC)-derived monocytes, but not T cells, cocultured via transwells with primary subcutaneous preadipocytes, increased proliferation (approximately twofold) and reduced differentiation (~50%) of preadipocytes. Gene expression analyses in proliferating preadipocytes (i.e., prior to hormonal induction of terminal differentiation) revealed that monocytes down-regulated mRNA levels of CCAAT/enhancer binding protein, alpha (C/EBPα) and up-regulated mRNA levels of G0/G1 switch 2 (G0S2) message, genes important for the regulation of adipogenesis and the cell cycle. These data indicate that circulating peripheral blood monocytes can disrupt adipogenesis by interfering with a critical step in C/EBPα and G0S2 transcription required for preadipocytes to make the transition from proliferation to differentiation. Interactions between preadipocytes and monocytes also increased the inflammatory cytokines IL-6 and IL-8, as well as a novel chemotactic cytokine, CXCL1. Additionally, the levels of both IL-6 and CXCL1 were highest when preadipocytes and monocytes were cultured together, compared to each cell in culture alone. Such cross-talk amplifies the production of mediators of tissue inflammation.

Combination of niacin and fenofibrate with lifestyle changes improves dyslipidemia and hypoadiponectinemia in HIV patients on antiretroviral therapy: results of "heart positive," a randomized, controlled trial.

CONTEXT: HIV patients on antiretroviral therapy (ART) have a unique dyslipidemia [elevated triglycerides and non-high-density lipoprotein-cholesterol (HDL-C), low HDL-C] with insulin resistance (characterized by hypoadiponectinemia). OBJECTIVE: The aim was to test a targeted, comprehensive, additive approach to treating the dyslipidemia. DESIGN AND SETTING: We conducted a randomized, double-blind, placebo-controlled, 24-wk trial of lifestyle modification, fenofibrate, and niacin in multiethnic HIV clinics at an academic center. PARTICIPANTS: Hypertriglyceridemic adult patients were stratified on three combinations of ART classes. Subjects retained at the first measurement (2 wk) after entry were included in the analysis (n = 191). INTERVENTIONS: Subjects were randomized into five treatment groups: usual care (group 1); low-saturated-fat diet and exercise (D/E; group 2); D/E + fenofibrate (group 3); D/E + niacin (group 4); or D/E + fenofibrate + niacin (group 5). MAIN OUTCOME MEASURES: We measured changes in fasting triglycerides, HDL-C, and non-HDL-C (primary), and in insulin sensitivity, glycemia, adiponectin, C-reactive protein, energy expenditure, and body composition (secondary). Data were analyzed as a factorial set of treatment combinations using a mixed repeated measures model, last observation carried forward, and complete case approaches (groups 2-5), and as an unstructured set of treatments (groups 1-5). RESULTS: Fenofibrate improved triglycerides (P = 0.002), total cholesterol (P = 0.02), and non-HDL-C (P = 0.003), whereas niacin improved HDL-C (P = 0.03), and both drugs decreased the total cholesterol-to-HDL-C ratio (P = 0.005-0.01). The combination of D/E, fenofibrate, and niacin provided maximal benefit, markedly reducing triglycerides (-52% compared to usual care; P = 0.003), increasing HDL-C (+12%; P < 0.001), and decreasing non-HDL-C (-18.5%; P = 0.003) and total cholesterol-to-HDL-C ratio (-24.5%; P < 0.001). Niacin doubled adiponectin levels. CONCLUSIONS: A combination of fenofibrate and niacin with low-saturated-fat D/E is effective and safe in increasing HDL-C, decreasing non-HDL-C and hypertriglyceridemia, and ameliorating hypoadiponectinemia in patients with HIV/ART-associated dyslipidemia.

Prevalence of diabetes, metabolic syndrome, and cardiovascular risk factors in US Asian Indians: results from a national study.

BACKGROUND: Although studies of immigrant Asian Indians in other countries show high rates of diabetes (DM), metabolic syndrome (MetS), and cardiovascular disease (CVD), no randomized, population-based studies of this rapidly growing ethnic group exist in the US. METHODS: The sample comprised 1038 randomly selected Asian Indian immigrants, aged 18 years and older at seven US sites. Prevalence of diabetes and MetS (age-adjusted and sex-adjusted means) was estimated and ANOVA was used to calculate gender and group differences (normoglycemia/impaired fasting glucose/diabetes) for CVD risk factors. RESULTS: The mean age was 48.2 years. The majority of respondents were male, married, educated, and with some form of health insurance. Prevalence of diabetes was 17.4%, and 33% of the respondents had prediabetes. Cardiovascular risk factors, especially high levels of triglycerides, total cholesterol, LDL cholesterol, homocysteine, and C-reactive protein, and low levels of HDL cholesterol, were also prevalent; elevated lipoprotein(a) was not observed. The age-adjusted prevalence of MetS was 26.9% by the original NCEP/ATP III criteria, 32.7% by the modified NCEP/ATP III criteria, and 38.2% by the IDF criteria. The MetS rates for women, but not for men, increased with age using all three criteria. There was a progressive worsening of all metabolic parameters as individuals progressed from normal to IFG to diabetes. CONCLUSION: The prevalence rates of diabetes and MetS among US Asian Indians are higher than reported in earlier, nonrandomized, smaller surveys. These data provide a firm basis for future mechanistic and interventional studies.

A-beta-subtype of ketosis-prone diabetes is not predominantly a monogenic diabetic syndrome.

OBJECTIVE: Ketosis-prone diabetes (KPD) is an emerging syndrome that encompasses several distinct phenotypic subgroups that share a predisposition to diabetic ketoacidosis. We investigated whether the A-beta- subgroup of KPD, characterized by complete insulin dependence, absent beta-cell functional reserve, lack of islet cell autoantibodies, and strong family history of type 2 diabetes, represents a monogenic form of diabetes. RESEARCH DESIGN AND METHODS: Over 8 years, 37 patients with an A-beta- phenotype were identified in our longitudinally followed cohort of KPD patients. Seven genes, including hepatocyte nuclear factor 4A (HNF4A), glucokinase (GCK), HNF1A, pancreas duodenal homeobox 1 (PDX1), HNF1B, neurogenic differentiation 1 (NEUROD1), and PAX4, were directly sequenced in all patients. Selected gene regions were also sequenced in healthy, unrelated ethnically matched control subjects, consisting of 84 African American, 96 Caucasian, and 95 Hispanic subjects. RESULTS: The majority (70%) of the A-beta- KPD patients had no significant causal polymorphisms in either the proximal promoter or coding regions of the seven genes. The combination of six potentially significant low-frequency, heterozygous sequence variants in HNF-1 alpha (A174V or G574S), PDX1 (putative 5'-untranslated region CCAAT box, P33T, or P239Q), or PAX4 (R133W) were found in 27% (10/37) of patients, with one additional patient revealing two variants, PDX1 P33T and PAX4 R133W. The A174V variant has not been previously reported. CONCLUSIONS: Despite its well-circumscribed, robust, and distinctive phenotype of severe, nonautoimmune-mediated beta-cell dysfunction, A-beta- KPD is most likely not a predominantly monogenic diabetic syndrome. Several A-beta- KPD patients have low-frequency variants in HNF1A, PDX1, or PAX4 genes, which may be of functional significance in their pathophysiology.