Leptin, an adipocyte-derived hormone, acts directly on the brain to control food intake and energy expenditure. An important question is the identity of first-order neurons initiating leptin's anti-obesity effects. A widely held view is that most, if not all, of leptin's effects are mediated by neurons located in the arcuate nucleus of the hypothalamus. However, leptin receptors (LEPRs) are expressed in other sites as well, including the ventromedial hypothalamus (VMH). The possible role of leptin acting in "nonarcuate" sites has largely been ignored. In the present study, we show that leptin depolarizes and increases the firing rate of steroidogenic factor-1 (SF1)-positive neurons in the VMH. We also show, by generating mice that lack LEPRs on SF1-positive neurons, that leptin action at this site plays an important role in reducing body weight and, of note, in resisting diet-induced obesity. These results reveal a critical role for leptin action on VMH neurons.

Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor (GHSR; ghrelin receptor). Since its discovery, accumulating evidence has suggested that ghrelin may play a role in signaling and reversing states of energy insufficiency. For example, ghrelin levels rise following food deprivation, and ghrelin administration stimulates feeding and increases body weight and adiposity. However, recent loss-of-function studies have raised questions regarding the physiological significance of ghrelin in regulating these processes. Here, we present results of a study using a novel GHSR-null mouse model, in which ghrelin administration fails to acutely stimulate food intake or activate arcuate nucleus neurons. We show that when fed a high-fat diet, both female and male GHSR-null mice eat less food, store less of their consumed calories, preferentially utilize fat as an energy substrate, and accumulate less body weight and adiposity than control mice. Similar effects on body weight and adiposity were also observed in female, but not male, GHSR-null mice fed standard chow. GHSR deletion also affected locomotor activity and levels of glycemia. These findings support the hypothesis that ghrelin-responsive pathways are an important component of coordinated body weight control. Moreover, our data suggest that ghrelin signaling is required for development of the full phenotype of diet-induced obesity.

RBM5 is a known modulator of apoptosis, an RNA binding protein, and a putative tumor suppressor. Originally identified as LUCA-15, and subsequently as H37, it was designated "RBM" (for RNA Binding Motif) due to the presence of two RRM (RNA Recognition Motif) domains within the protein coding sequence. Recently, a number of proteins have been attributed with this same RBM designation, based on the presence of one or more RRM consensus sequences. One such protein, RBM3, was also recently found to have apoptotic modulatory capabilities. The high sequence homology at the amino acid level between RBM5, RBM6, and particularly, RBM10 suggests that they, too, may play an important role in regulating apoptosis. It is the intent of this article to ammalgamate the data on the ten originally identified RBM proteins in order to question the existence of a novel family of RNA binding apoptosis regulators.

Transient receptor potential canonical (TRPC) proteins form nonselective cation channels that play physiological roles in a wide variety of cells. Despite growing evidence supporting the therapeutic potential of TRPC6 inhibition in treating pathological cardiac and renal conditions, mechanistic understanding of TRPC6 function and modulation remains obscure. Here we report cryo-EM structures of TRPC6 in both antagonist-bound and agonist-bound states. The structures reveal two novel recognition sites for the small-molecule modulators corroborated by mutagenesis data. The antagonist binds to a cytoplasm-facing pocket formed by S1-S4 and the TRP helix, whereas the agonist wedges at the subunit interface between S6 and the pore helix. Conformational changes upon ligand binding illuminate a mechanistic rationale for understanding TRPC6 modulation. Furthermore, structural and mutagenesis analyses suggest several disease-related mutations enhance channel activity by disrupting interfacial interactions. Our results provide principles of drug action that may facilitate future design of small molecules to ameliorate TRPC6-mediated diseases.

A series of naphthyl-based compounds were synthesized as potential inhibitors of vascular endothelial growth factor (VEGF) receptors. Investigations of structure-activity relationships led to the identification of a series of naphthamides that are potent inhibitors of the VEGF receptor tyrosine kinase family. Numerous analogues demonstrated low nanomolar inhibition of VEGF-dependent human umbilical vein endothelial cell (HUVEC) proliferation, and of these several compounds possessed favorable pharmacokinetic (PK) profiles. In particular, compound 48 demonstrated significant antitumor efficacy against established HT29 human colon adenocarcinoma xenografts implanted in athymic mice. A full account of the preparation, structure-activity relationships, pharmacokinetic properties, and pharmacology of analogues within this series is presented.

The lymphocyte-specific kinase (Lck) is a cytoplasmic tyrosine kinase of the Src family expressed in T cells and natural killer (NK) cells. Genetic evidence in both mice and humans demonstrates that Lck kinase activity is critical for signaling mediated by the T cell receptor (TCR), which leads to normal T cell development and activation. Selective inhibition of Lck is expected to offer a new therapy for the treatment of T-cell-mediated autoimmune and inflammatory disease. Screening of our kinase-preferred collection identified aminoquinazoline 1 as a potent, nonselective inhibitor of Lck and T cell proliferation. In this report, we describe the synthesis and structure-activity relationships of a series of novel aminoquinazolines possessing in vitro mechanism-based potency. Optimized, orally bioavailable compounds 32 and 47 exhibit anti-inflammatory activity (ED(50) of 22 and 11 mg/kg, respectively) in the anti-CD3-induced production of interleukin-2 (IL-2) in mice.

The optimization of a series of aminooxazoline xanthene inhibitors of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is described. An early lead compound showed robust Aβ lowering activity in a rat pharmacodynamic model, but advancement was precluded by a low therapeutic window to QTc prolongation in cardiovascular models consistent with in vitro activity on the hERG ion channel. While the introduction of polar groups was effective in reducing hERG binding affinity, this came at the expense of higher than desired Pgp-mediated efflux. A balance of low Pgp efflux and hERG activity was achieved by lowering the polar surface area of the P3 substituent while retaining polarity in the P2' side chain. The introduction of a fluorine in position 4 of the xanthene ring improved BACE1 potency (5-10-fold). The combination of these optimized fragments resulted in identification of compound 40, which showed robust Aβ reduction in a rat pharmacodynamic model (78% Aβ reduction in CSF at 10 mg/kg po) and also showed acceptable cardiovascular safety in vivo.

The CB2 receptor is an attractive therapeutic target for analgesic and anti-inflammatory agents. Herein we describe the discovery of a novel class of oxadiazole derivatives from which potent and selective CB2 agonist leads were developed. Initial hit 7 was identified from a cannabinoid target-biased library generated by virtual screening of sample collections using a pharmacophore model in combination with a series of physicochemical filters. 7 was demonstrated to be a selective CB2 agonist (CB2 EC50 = 93 nM, Emax = 98%, CB1 EC50 > 10 microM). However, this compound exhibited poor solubility and relatively high clearance in rat, resulting in low oral bioavailability. In this paper, we report detailed SAR studies on 7 en route toward improving potency, physicochemical properties, and solubility. This effort resulted in identification of 63 that is a potent and selective agonist at CB2 (EC50 = 2 nM, Emax = 110%) with excellent pharmacokinetic properties.