Metabolic Syndrome Nonalcoholic Steatohepatitis Male Mouse With Adeno-Associated Viral Renin as a Novel Model for Heart Failure With Preserved Ejection Fraction.

Background: Heart failure with preserved ejection fraction (HFpEF) currently accounts for more than half of patients with HF, with limited approved evidence-based therapies. HFpEF is a complex multifactorial disease associated with hypertension, obesity, diabetes, and renal dysfunction. In addition to our limited understanding of HFpEF pathophysiology, the development of new therapies is partially hindered by the existing translationally relevant preclinical HFpEF models.

Two-hit mouse model of heart failure with preserved ejection fraction combining diet-induced obesity and renin-mediated hypertension.

Unlabelled: Heart failure with preserved ejection fraction (HFpEF) is increasingly common but its pathogenesis is poorly understood. The ability to assess genetic and pharmacologic interventions is hampered by the lack of robust preclinical mouse models of HFpEF. We have developed a novel "2-hit" model, which combines obesity and insulin resistance with chronic pressure overload to recapitulate clinical features of HFpEF.

Regulated dynamic subcellular GLUT4 localization revealed by proximal proteome mapping in human muscle cells.

Regulation of glucose transport, which is central for control of whole-body metabolism, is determined by the amount of GLUT4 glucose transporter (also known as SLC2A4) in the plasma membrane (PM) of fat and muscle cells. Physiologic signals [such as activated insulin receptor or AMP-activated protein kinase (AMPK)] increase PM GLUT4. Here, we show that the distribution of GLUT4 between the PM and interior of human muscle cells is dynamically maintained, and that AMPK promotes PM redistribution of GLUT4 by regulating exocytosis and endocytosis.

Small molecule branched-chain ketoacid dehydrogenase kinase (BDK) inhibitors with opposing effects on BDK protein levels.

Branched chain amino acid (BCAA) catabolic impairments have been implicated in several diseases. Branched chain ketoacid dehydrogenase (BCKDH) controls the rate limiting step in BCAA degradation, the activity of which is inhibited by BCKDH kinase (BDK)-mediated phosphorylation. Screening efforts to discover BDK inhibitors led to identification of thiophene PF-07208254, which improved cardiometabolic endpoints in mice.

GLUT4 dynamic subcellular localization is controlled by AMP kinase activation as revealed by proximal proteome mapping in human muscle cells.

Regulation of glucose transport into muscle and adipocytes, central for control of whole-body metabolism, is determined by the amount of GLUT4 glucose transporter in the plasma membrane ( ). Physiologic signals (activated insulin receptor or AMP kinase [ ]), acutely increase PM GLUT4 to enhance glucose uptake. Here we show in kinetic studies that intracellular GLUT4 is in equilibrium with the PM in unstimulated cultured human skeletal muscle cells, and that AMPK promotes GLUT4 redistribution to the PM by regulating both exocytosis and endocytosis.

Branched-chain amino acid catabolism in muscle affects systemic BCAA levels but not insulin resistance.

Elevated levels of plasma branched-chain amino acids (BCAAs) have been associated with insulin resistance and type 2 diabetes since the 1960s. Pharmacological activation of branched-chain α-ketoacid dehydrogenase (BCKDH), the rate-limiting enzyme of BCAA oxidation, lowers plasma BCAAs and improves insulin sensitivity. Here we show that modulation of BCKDH in skeletal muscle, but not liver, affects fasting plasma BCAAs in male mice.

CHAC1 inactivation is effective to preserve muscle glutathione but is insufficient to protect against muscle wasting in cachexia.

Muscle wasting is one of the main characteristics of cachexia associated with cancer and other chronic diseases and is often exacerbated by antineoplastic agents. Increased oxidative stress is associated with muscle wasting, along with depletion of glutathione, the most abundant endogenous antioxidant. Therefore, boosting endogenous glutathione has been proposed as a therapeutic strategy to prevent muscle wasting.

GDF15 neutralization restores muscle function and physical performance in a mouse model of cancer cachexia.

Cancer cachexia is a disorder characterized by involuntary weight loss and impaired physical performance. Decline in physical performance of patients with cachexia is associated with poor quality of life, and currently there are no effective pharmacological interventions that restore physical performance. Here we examine the effect of GDF15 neutralization in a mouse model of cancer-induced cachexia (TOV21G) that manifests weight loss and muscle function impairments.

BDK inhibition acts as a catabolic switch to mimic fasting and improve metabolism in mice.

Objective: Branched chain amino acid (BCAA) catabolic defects are implicated to be causal determinates of multiple diseases. This work aimed to better understand how enhancing BCAA catabolism affected metabolic homeostasis as well as the mechanisms underlying these improvements.

Methods: The rate limiting step of BCAA catabolism is the irreversible decarboxylation by the branched chain ketoacid dehydrogenase (BCKDH) enzyme complex, which is post-translationally controlled through phosphorylation by BCKDH kinase (BDK).

Neutralization of GDF15 Prevents Anorexia and Weight Loss in the Monocrotaline-Induced Cardiac Cachexia Rat Model.

Growth and differentiation factor 15 (GDF15) is a cytokine reported to cause anorexia and weight loss in animal models. Neutralization of GDF15 was efficacious in mitigating cachexia and improving survival in cachectic tumor models. Interestingly, elevated circulating GDF15 was reported in patients with pulmonary arterial hypertension and heart failure, but it is unclear whether GDF15 contributes to cachexia in these disease conditions.

Growth differentiation factor 15 neutralization does not impact anorexia or survival in lipopolysaccharide-induced inflammation.

Growth differentiation factor 15 (GDF15) causes anorexia and weight loss in animal models, and higher circulating levels are associated with cachexia and reduced survival in cancer and other chronic diseases such as sepsis. To investigate the role of sepsis-induced GDF15, we examined whether GDF15 neutralization via a validated and highly potent monoclonal antibody, mAB2, modulates lipopolysaccharide (LPS)-induced anorexia, weight loss, and mortality in rodents. LPS injection transiently increased circulating GDF15 in wild-type mice, decreased food intake and body weight, and increased illness behavior and mortality at a high dose.

GDF-15 Neutralization Alleviates Platinum-Based Chemotherapy-Induced Emesis, Anorexia, and Weight Loss in Mice and Nonhuman Primates.

Platinum-based cancer therapy is restricted by dose-limiting side effects and is associated with elevation of growth differentiation factor 15 (GDF-15). But whether this elevation contributes to such side effects has been unclear. Here, we explored the effects of GDF-15 blockade on platinum-based chemotherapy-induced emesis, anorexia, and weight loss in mice and/or nonhuman primate models.

GDF15 Provides an Endocrine Signal of Nutritional Stress in Mice and Humans.

GDF15 is an established biomarker of cellular stress. The fact that it signals via a specific hindbrain receptor, GFRAL, and that mice lacking GDF15 manifest diet-induced obesity suggest that GDF15 may play a physiological role in energy balance. We performed experiments in humans, mice, and cells to determine if and how nutritional perturbations modify GDF15 expression.

[Deuterium isotope characteristics of precipitation infiltrated in the West Ordos Desert of Inner Mongolia, China].

Understanding the soil-profile temporal and spatial distribution of rainwater in arid and semiarid regions provides a scientific basis for the restoration and maintenance of degraded desert ecosystems in the West Ordos Desert of Inner Mongolia, China. In this study, the deuterium isotope (δD) value of rainwater, soil water, and groundwater were examined in the West Ordos Desert. The contribution of precipitation to soil water in each layer of the soil profile was calculated with two-end linear mixed model.

Hepatic GALE Regulates Whole-Body Glucose Homeostasis by Modulating Expression.

Transcripts of key enzymes in the Leloir pathway of galactose metabolism in mouse livers are significantly increased after chronic high-fat/high-sucrose feeding. UDP-galactose-4-epimerase (GALE) is the last enzyme in this pathway that converts UDP-galactose to UDP-glucose and was previously identified as a downstream target of the endoplasmic reticulum (ER) stress effector spliced X-box binding protein 1, suggesting an interesting cross talk between galactose and glucose metabolism in the context of hepatic ER stress and whole-body metabolic fitness. However, its specific role in glucose metabolism is not established.

The metabolic effects of GDF15 are mediated by the orphan receptor GFRAL.

Growth/differentiation factor 15 (GDF15), also known as MIC-1, is a distant member of the transforming growth factor-β (TGF-β) superfamily and has been implicated in various biological functions, including cancer cachexia, renal and heart failure, atherosclerosis and metabolism. A connection between GDF15 and body-weight regulation was initially suggested on the basis of an observation that increasing GDF15 levels in serum correlated with weight loss in individuals with advanced prostate cancer. In animal models, overexpression of GDF15 leads to a lean phenotype, hypophagia and other improvements in metabolic parameters, suggesting that recombinant GDF15 protein could potentially be used in the treatment of obesity and type 2 diabetes.

SAR exploration at the C-3 position of tetrahydro-β-carboline sstr3 antagonists.

MK-4256, a tetrahydro-β-carboline sstr3 antagonist, was discontinued due to a cardiovascular (CV) adverse effect observed in dogs. Additional investigations revealed that the CV liability (QTc prolongation) was caused by the hERG off-target activity of MK-4256 and was not due to sstr3 antagonism. In this Letter, we describe our extensive SAR effort at the C3 position of the tetrahydro-β-carboline structure.

A novel series of indazole-/indole-based glucagon receptor antagonists.

A novel, potent series of glucagon receptor antagonists (GRAs) was discovered. These indazole- and indole-based compounds were designed on an earlier pyrazole-based GRA lead MK-0893. Structure-activity relationship (SAR) studies were focused on the C3 and C6 positions of the indazole core, as well as the benzylic position on the N-1 of indazole.

Discovery of MK-1421, a Potent, Selective sstr3 Antagonist, as a Development Candidate for Type 2 Diabetes.

The imidazolyl-tetrahydro-β-carboline class of sstr3 antagonists have demonstrated efficacy in a murine model of glucose excursion and may have potential as a treatment for type 2 diabetes. The first candidate in this class caused unacceptable QTc interval prolongation in oral, telemetrized cardiovascular (CV) dogs. Herein, we describe our efforts to identify an acceptable candidate without CV effects.

Diamine Derivatives as Novel Small-Molecule, Potent, and Subtype-Selective Somatostatin SST3 Receptor Agonists.

A novel class of small-molecule, highly potent, and subtype-selective somatostatin SST3 agonists was discovered through modification of a SST3 antagonist. As an example, (1R,2S)-9 demonstrated not only potent in vitro SST3 agonist activity but also in vivo SST3 agonist activity in a mouse oral glucose tolerance test (OGTT). These agonists may be useful reagents for studying the physiological roles of the SST3 receptor and may potentially be useful as therapeutic agents.

Anti-diabetic efficacy and impact on amino acid metabolism of GRA1, a novel small-molecule glucagon receptor antagonist.

Hyperglucagonemia is implicated in the pathophysiology of hyperglycemia. Antagonism of the glucagon receptor (GCGR) thus represents a potential approach to diabetes treatment. Herein we report the characterization of GRA1, a novel small-molecule GCGR antagonist that blocks glucagon binding to the human GCGR (hGCGR) and antagonizes glucagon-induced intracellular accumulation of cAMP with nanomolar potency.

The role of voltage-gated potassium channels Kv2.1 and Kv2.2 in the regulation of insulin and somatostatin release from pancreatic islets.

The voltage-gated potassium channels Kv2.1 and Kv2.2 are highly expressed in pancreatic islets, yet their contribution to islet hormone secretion is not fully understood.

Discovery of a novel glucagon receptor antagonist N-[(4-{(1S)-1-[3-(3, 5-dichlorophenyl)-5-(6-methoxynaphthalen-2-yl)-1H-pyrazol-1-yl]ethyl}phenyl)carbonyl]-β-alanine (MK-0893) for the treatment of type II diabetes.

A potent, selective glucagon receptor antagonist 9m, N-[(4-{(1S)-1-[3-(3,5-dichlorophenyl)-5-(6-methoxynaphthalen-2-yl)-1H-pyrazol-1-yl]ethyl}phenyl)carbonyl]-β-alanine, was discovered by optimization of a previously identified lead. Compound 9m is a reversible and competitive antagonist with high binding affinity (IC(50) of 6.6 nM) and functional cAMP activity (IC(50) of 15.

The Discovery of MK-4256, a Potent SSTR3 Antagonist as a Potential Treatment of Type 2 Diabetes.

A structure-activity relationship study of the imidazolyl-β-tetrahydrocarboline series identified MK-4256 as a potent, selective SSTR3 antagonist, which demonstrated superior efficacy in a mouse oGTT model. MK-4256 reduced glucose excursion in a dose-dependent fashion with maximal efficacy achieved at doses as low as 0.03 mg/kg po.

A genome-wide siRNA screen to identify modulators of insulin sensitivity and gluconeogenesis.

Background: Hepatic insulin resistance impairs insulin's ability to suppress hepatic glucose production (HGP) and contributes to the development of type 2 diabetes (T2D). Although the interests to discover novel genes that modulate insulin sensitivity and HGP are high, it remains challenging to have a human cell based system to identify novel genes.

Methodology/principal Findings: To identify genes that modulate hepatic insulin signaling and HGP, we generated a human cell line stably expressing beta-lactamase under the control of the human glucose-6-phosphatase (G6PC) promoter (AH-G6PC cells).