Publications by authors named "Mark Player"

Acute Kidney Injury (AKI) is characterized by an abrupt decline in kidney function and has been associated with excess risks of death, kidney disease progression, and cardiovascular events. The kidney has a high energetic demand with mitochondrial health being essential to renal function and damaged mitochondria has been reported across AKI subtypes. 5' adenosine monophosphate-activated protein kinase (AMPK) activation preserves cellular energetics through improvement of mitochondrial function and biogenesis when ATP levels are low such as under ischemia-induced AKI.

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The free fatty acid receptor 1 (FFAR1/GPR40) mediates fatty acid-induced insulin secretion from pancreatic β-cells. At least 3 distinct binding sites exist on the FFAR1 receptor and numerous synthetic ligands have been investigated for their anti-diabetic actions. Fasiglifam, binds to site-1 and stimulates intra-cellular calcium release and improves glycemic control in diabetic patients.

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GPR40 is a G-protein-coupled receptor which mediates fatty acid-induced glucose-stimulated insulin secretion from pancreatic beta cells and incretion release from enteroendocrine cells of the small intestine. GPR40 full agonists exhibit superior glucose lowering compared to partial agonists in preclinical species due to increased insulin and GLP-1 secretion, with the added benefit of promoting weight loss. In our search for potent GPR40 full agonists, we discovered a superagonist which displayed excellent in vitro potency and superior efficacy in the Gα-mediated signaling pathway.

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GPR40 is a clinically validated molecular target for the treatment of diabetes. Many GPR40 agonists have been identified to date, with the partial agonist fasiglifam (TAK-875) reaching phase III clinical trials before its development was terminated due to off-target liver toxicity. Since then, attention has shifted toward the development of full agonists that exhibit superior efficacy in preclinical models.

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Compound 12 is a GPR40 agonist that realizes the full magnitude of efficacy possible via GPR40 receptor agonism. In vitro and in vivo studies demonstrated superior glucose lowering by 12 compared to fasiglifam (TAK-875), in a glucose dependent manner. The enhanced efficacy observed with the full agonist 12 was associated with both direct and indirect stimulation of insulin secretion.

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GPR40 partial agonism is a promising new mechanism for the treatment of type 2 diabetes mellitus with clinical proof of concept. Most of the GPR40 agonists in the literature have a carboxylic acid functional group, which may pose a risk for idiosyncratic drug toxicity. A novel series of GPR40 agonists containing a tetrazole as a carboxylic acid bioisostere was identified.

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Article Synopsis
  • ERRα is an orphan nuclear receptor involved in energy regulation, and new N-alkylthiazolidenediones were developed as selective inverse agonists for it.
  • Multiple compounds were optimized, leading to a potent analogue that not only inhibited co-activator recruitment in vitro but also lowered insulin and triglyceride levels in a pre-diabetic rat model.
  • The most promising compound (50) showed similar effects on glucose control and triglyceride reduction in mice models without causing weight gain, indicating its potential for treating metabolic diseases.
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TAK-875, a GPR40 agonist, was withdrawn from Phase III clinical trials due to drug-induced liver injury (DILI). Mechanistic studies were conducted to identify potential DILI hazards (covalent binding burden (CVB), hepatic transporter inhibition, mitochondrial toxicity, and liver toxicity in rats) associated with TAK-875. Treatment of hepatocytes with radiolabeled TAK-875 resulted in a CVB of 2.

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Design and optimization of a novel series of imidazo[1,2-b]pyridazine PDE10a inhibitors are described. Compound 31 displays excellent pharmacokinetic properties and was also evaluated as an insulin secretagogue in vitro and in vivo.

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Reported herein is the design, synthesis, and pharmacologic characterization of a class of TRPV1 antagonists constructed on a benzo[d]imidazole platform that evolved from a biaryl amide lead. This design composes three sections: a 2-substituted 5-phenyl headgroup attached to the benzo[d]imidazole platform, which is tethered at the two position to a phenyl tail group. Optimization of this design led to the identification of 4 (mavatrep), comprising a trifluoromethyl-phenyl-vinyl tail.

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Objectives: Mild decrease in core temperature (therapeutic hypothermia) provides lasting neuroprotection following cardiac arrest or cerebral ischemia. However, current methods for producing therapeutic hypothermia trigger a cold-defense response that must be countered by sedatives, muscle paralytics, and mechanical ventilation. We aimed to determine methods for producing hypothermia in the conscious mouse by targeting two transient receptor potential channels involved in thermoregulation, two transient receptor potential (TRP) channels involved in thermoregulation, TRP vanilloid 1 (TRPV1) and TRP melastatin 8 (TRPM8).

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Structure-activity relationship (SAR) studies on a highly potent series of arylamide FMS inhibitors were carried out with the aim of improving FMS kinase selectivity, particularly over KIT. Potent compound 17r (FMS IC50 0.7 nM, FMS cell IC50 6.

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Mild decrease of core temperature (32-34°C), also known as therapeutic hypothermia, is a highly effective strategy of neuroprotection from ischemia and holds significant promise in the treatment of stroke. However, induction of hypothermia in conscious stroke patients is complicated by cold-defensive responses, such as shivering and tachycardia. Although multiple thermoregulatory responses may be altered by modulators of thermosensitive ion channels, TRPM8 (transient receptor potential melastatin 8) and TRPV1 (TRP vanilloid 1), it is unknown whether these agents affect cold-induced shivering and tachycardia.

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Thermosensitive transient receptor potential melastatin 8 (TRPM8) antagonists are considered to be potential therapeutic agents for the treatment of cold hypersensitivity. The discovery of a new class of TRPM8 antagonists that shows in vivo efficacy in the rat chronic constriction injury (CCI)-induced model of neuropathic pain is described.

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A class of potent inhibitors of colony-stimulating factor-1 receptor (CSF-1R or FMS), as exemplified by 8 and 21, was optimized to improve pharmacokinetic and pharmacodynamic properties and potential toxicological liabilities. Early stage absorption, distribution, metabolism, and excretion assays were employed to ensure the incorporation of druglike properties resulting in the selection of several compounds with good activity in a pharmacodynamic screening assay in mice. Further investigation, utilizing the type II collagen-induced arthritis model in mice, culminated in the selection of anti-inflammatory development candidate JNJ-28312141 (23, FMS IC(50) = 0.

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Estrogen-related receptor α (ERRα) is an orphan nuclear receptor that has been functionally implicated in the regulation of energy homeostasis. Herein is described the development of diaryl ether based thiazolidenediones, which function as selective ligands against this receptor. Series optimization provided several potent analogues that inhibit the recruitment of a coactivator peptide fragment in in vitro biochemical assays (IC(50) < 150 nM) and cellular two-hybrid reporter assays against the ligand binding domain (IC(50) = 1-5 μM).

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Transient receptor potential melastatin 8 (TRPM8) is a nonselective cation channel that is thermoresponsive to cool to cold temperatures (8-28 °C) and also may be activated by chemical agonists such as menthol and icilin. Antagonism of TRPM8 activation is currently under investigation for the treatment of painful conditions related to cold, such as cold allodynia and cold hyperalgesia. The design, synthesis, and optimization of a class of selective TRPM8 antagonists based on a benzimidazole scaffold is described, leading to the identification of compounds that exhibited potent antagonism of TRPM8 in cell-based functional assays for human, rat, and canine TRPM8 channels.

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During efforts to improve the bioavailability of FMS kinase inhibitors 1 and 2, a series of saturated and aromatic 4-heterocycles of reduced basicity were prepared and evaluated in an attempt to also improve the cardiovascular safety profile over lead arylamide 1, which possessed ion channel activity. The resultant compounds retained excellent potency and exhibited diminished ion channel activity.

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We have identified RWJ-671818 (8) as a novel, low molecular weight, orally active inhibitor of human alpha-thrombin (K(i) = 1.3 nM) that is potentially useful for the acute and chronic treatment of venous and arterial thrombosis. In a rat deep venous thrombosis model used to assess antithrombotic efficacy, oral administration of 8 at 30 and 50 mg/kg reduced thrombus weight by 87 and 94%, respectively.

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Thromboembolic diseases are the leading causes of morbidity and mortality in the developed world. Anticoagulants provide effective treatment for venous or arterial thromboembolism. Two coagulation factors, factor Xa (fXa) and thrombin, are the primary targets under active investigation for anticoagulant therapy.

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FMS is the exclusive receptor tyrosine kinase for colony-stimulating factor-1 (CSF-1, also known as M-CSF), which regulates the survival, proliferation, differentiation, and function of macrophage lineage cells. Since CSF-1 is over-expressed in many tumors and at sites of inflammation, small molecule inhibitors of CSF-1 appear to offer an attractive strategy for reducing macrophage numbers associated with cancer as well as autoimmune and inflammatory disease, such as rheumatoid arthritis (RA). Numerous FMS inhibitors with structurally distinct chemotypes have been developed and exhibit potent in vitro activity, but only a limited number of compounds have progressed clinically due to poor selectivity.

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A series of pyrido[2,3-d]pyrimidin-5-ones has been synthesized and evaluated as inhibitors of the kinase domain of macrophage colony-stimulating factor-1 receptor (FMS). FMS inhibitors may be useful in treating rheumatoid arthritis and other chronic inflammatory diseases. Structure-based optimization of the lead amide analogue 10 led to hydroxamate analogue 37, which possessed excellent potency and an improved pharmacokinetic profile.

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