An orally available, brain-penetrant CAMKK2 inhibitor reduces food intake in rodent model.

Hypothalamic CAMKK2 represents a potential mechanism for chemically affecting satiety and promoting weight loss in clinically obese patients. Single-digit nanomolar inhibitors of CAMKK2 were identified in three related ATP-competitive series. Limited optimization of kinase selectivity, solubility, and pharmacokinetic properties were undertaken on all three series, as SAR was often transferrable. Ultimately, a 2,4-diaryl 7-azaindole was optimized to afford a tool molecule that potently inhibits AMPK phosphorylation in a hypothalamus-derived cell line, is orally bioavailable, and crosses the blood-brain barrier. When dosed orally in rodents, compound 4 t limited ghrelin-induced food intake.

Paradoxical response to the sedative effects of diazepam and alcohol in C57BL/6J mice lacking the neuropeptide S receptor.

The neuropeptide S (NPS) system is characterized by a unique pharmacology because it has anxiolytic-like effects and promotes arousal and wakefulness. To shed light on this peptidergic system, we tested the sedative effect of the central depressants diazepam and ethanol on the loss of righting reflex in mice lacking the neuropeptide S receptor (NPSR), NPSR(-/-). Furthermore, we tested the effect of the intracerebroventricular (ICV) administration of NPS on the sedative effect of diazepam and ethanol in NPSR(-/-) and their wild type counterpart NPSR(+/+). Finally, we evaluated the effect of the pro-arousal neuropeptides CRF and Hcrt-1/Ox-A in NPSR-deficient mice. Contrary to our expectations, the results showed that the NPSR(-/-) were less sensitive to the hypnotic effects of both diazepam and ethanol compared with their wild type littermates. ICV NPS was able to attenuate the sedative effect of both alcohol and diazepam in wild type mice, but not in the NPSR(-/-) line. The administration of CRF and Hcrt-1/Ox-A, two classic pro-arousal peptides, elicited the same effects in both NPSR(-/-) and wild type mice, ruling out the possibility that adaptive mechanisms occurring at the level of these two systems could have occurred during NPSR(-/-) development to compensate for the lack of NPSR receptors. Our findings demonstrated that the deletion of NPSR leads to minor changes in the arousal behavior of mice. Moreover, we demonstrated that the deletion of NPSR did not lead to compensatory changes in the vigilance-promoting effects of the CRF and Hcrt-1/Ox-A systems.

Pharmacological characterization of the ghrelin receptor antagonist, GSK1614343 in rat RC-4B/C cells natively expressing GHS type 1a receptors.

A novel growth hormone secretagogues type 1a (GHS1a) receptors antagonist (2R)-N'-[3,5- bis(trifluoromethyl)phenyl]-2-[(8aR)-hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]-2-(3- pyridinyl)ethanohydrazide (GSK1614343) was functionally characterised in rat pituitary adenoma cell line, RC-4B/C endogenously expressing GHS1a receptors. The antagonism profile of GSK1614343 was compared with that of 6-[(4-fluorophenyl)oxy]-2-methyl-3-{[(3S)-1-(1-methylethyl)-3- piperidinyl]methyl}-4(3H)-quinazolinone (YIL-781) another ghrelin receptor antagonist recently published. The activity of both compounds was also evaluated at rat recombinant GHS1a receptors. The characterization of the two antagonists was performed by intracellular calcium mobilization measurements by using fluorometric imaging plate reader (FLIPR) technology and inositol phosphate (IP) turnover measurements by [3H]-IP accumulation assay. RC-4B/C and U2-OS cells transiently transduced with rat GHS1a receptors virus were used. In RC-4B/C cells, GSK1614343 and YIL-781, depressed the ghrelin maximal response in FLIPR assay as result of hemi-equilibria phenomenon. When using the [3H]-IP accumulation assay both compounds behaved as competitive antagonist with pKB values of 8.03 for GSK1614343 and 7.54 for YIL-781. In rat recombinant receptor, GSK1614343 and YIL-781 inhibited the calcium response induced by ghrelin with pIC50 values of 7.90 and 8.27, respectively. GSK1614343 and YIL-781 did not show intrinsic activity in both endogenously expressed and recombinant rat GHS1a receptors. The new ghrelin receptor antagonist GSK1614343 is a potent competitive antagonist in rat pituitary RC-4B/C cells endogenously expressing GHS1a receptors when equilibrium conditions between ligand and receptor are reached in the test assay. GSK1614343 represents a useful tool to investigate the physiological relevance of the ghrelin system in rat models.

Scanning the Escherichia coli chromosome by random transposon mutagenesis and multiple phenotypic screening.

Analysis of the complete DNA sequences of many microbial genomes available reveals a fair number of putative ORFs without an identified function. A systematic scan of the Escherichia coli chromosome was achieved by random transposition with a newly developed Tn5 minitransposon derivative carrying the arabinose-inducible araP(BAD) promoter oriented outward at one end (Tn5-araP(BAD)). The transposon insertion mutants obtained were assayed for conditional lethal phenotypes (arabinose dependence or sensitivity), for growth at two temperatures (37 and 15 degrees C) and in different media (rich and minimal medium). The Tn5-araP(BAD)-tagged genes were identified by sequencing the transposon insertion points. In this way we found a new essential gene cluster (yhbN-yhbG), produced conditional lethal (arabinose-dependent) mutations in already known essential genes (folD, frr, plsC, thiL, serS, thrS, and trpS) and provided a new phenotype (cold sensitivity) to other known genes (holD, ahpC, and tolA). Moreover, we identified eight putative ORFs (kch, ycaM, ycbQ, yddA, yddB, ydeK, ydeX, and yliF) that appear to be required in optimum growth conditions (rich medium at 37 degrees C) but not in the cold and in minimal medium.