A Dual Inhibitor of DYRK1A and GSK3β for β-Cell Proliferation: Aminopyrazine Derivative GNF4877

Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation.

Selective DYRK1A Inhibitor for the Treatment of Type 1 Diabetes: Discovery of 6-Azaindole Derivative GNF2133

Autoimmune deficiency and destruction in either β-cell mass or function can cause insufficient insulin levels and, as a result, hyperglycemia and diabetes. Thus, promoting β-cell proliferation could be one approach toward diabetes intervention. In this report we describe the discovery of a potent and selective DYRK1A inhibitor GNF2133, which was identified through optimization of a 6-azaindole screening hit. In vitro, GNF2133 is able to proliferate both rodent and human β-cells. In vivo, GNF2133 demonstrated significant dose-dependent glucose disposal capacity and insulin secretion in response to glucose-potentiated arginine-induced insulin secretion (GPAIS) challenge in rat insulin promoter and diphtheria toxin A (RIP-DTA) mice. The work described here provides new avenues to disease altering therapeutic interventions in the treatment of type 1 diabetes (T1D).

Identification of a small molecule that stimulates human β-cell proliferation and insulin secretion, and protects against cytotoxic stress in rat insulinoma cells

A key event in the development of both major forms of diabetes is the loss of functional pancreatic islet β-cell mass. Strategies aimed at enhancing β-cell regeneration have long been pursued, but methods for reliably inducing human β-cell proliferation with full retention of key functions such as glucose-stimulated insulin secretion (GSIS) are still very limited. We have previously reported that overexpression of the homeobox transcription factor NKX6.1 stimulates β-cell proliferation, while also enhancing GSIS and providing protection against β-cell cytotoxicity through induction of the VGF prohormone. We developed an NKX6.1 pathway screen by stably transfecting 832/13 rat insulinoma cells with a VGF promoter-luciferase reporter construct, using the resultant cell line to screen a 630,000 compound chemical library. We isolated three compounds with consistent effects to stimulate human islet cell proliferation, but not expression of NKX6.1 or VGF, suggesting an alternative mechanism of action. Further studies of the most potent of these compounds, GNF-9228, revealed that it selectively activates human β-cell relative to α-cell proliferation and has no effect on δ-cell replication. In addition, pre-treatment, but not short term exposure of human islets to GNF-9228 enhances GSIS. GNF-9228 also protects 832/13 insulinoma cells against ER stress- and inflammatory cytokine-induced cytotoxicity. GNF-9228 stimulates proliferation via a mechanism distinct from recently emergent DYRK1A inhibitors, as it is unaffected by DYRK1A overexpression and does not activate NFAT translocation. In conclusion, we have identified a small molecule with pleiotropic positive effects on islet biology, including stimulation of human β-cell proliferation and insulin secretion, and protection against multiple agents of cytotoxic stress.

Nidufexor (LMB763), a Novel FXR Modulator for the Treatment of Nonalcoholic Steatohepatitis

Farnesoid X receptor (FXR) agonists are emerging as important potential therapeutics for the treatment of nonalcoholic steatohepatitis (NASH) patients, as they exert positive effects on multiple aspects of the disease. FXR agonists reduce lipid accumulation in the liver, hepatocellular inflammation, hepatic injury, and fibrosis. While there are currently no approved therapies for NASH, the bile acid-derived FXR agonist obeticholic acid (OCA; 6-ethyl chenodeoxycholic acid) has shown promise in clinical studies. Previously, we described the discovery of tropifexor (LJN452), the most potent non-bile acid FXR agonist currently in clinical investigation. Here, we report the discovery of a novel chemical series of non-bile acid FXR agonists based on a tricyclic dihydrochromenopyrazole core from which emerged nidufexor (LMB763), a compound with partial FXR agonistic activity in vitro and FXR-dependent gene modulation in vivo. Nidufexor has advanced to Phase 2 human clinical trials in patients with NASH and diabetic nephropathy.

Tropifexor-Mediated Abrogation of Steatohepatitis and Fibrosis Is Associated With the Antioxidative Gene Expression Profile in Rodents

Farnesoid X receptor (FXR) agonism is emerging as an important potential therapeutic mechanism of action for multiple chronic liver diseases. The bile acid‐derived FXR agonist obeticholic acid (OCA) has shown promise in a phase 2 study in patients with nonalcoholic steatohepatitis (NASH). Here, we report efficacy of the novel nonbile acid FXR agonist tropifexor (LJN452) in two distinct preclinical models of NASH. The efficacy of tropifexor at <1 mg/kg doses was superior to that of OCA at 25 mg/kg in the liver in both NASH models. In a chemical and dietary model of NASH (Stelic animal model [STAM]), tropifexor reversed established fibrosis and reduced the nonalcoholic fatty liver disease activity score and hepatic triglycerides. In an insulin‐resistant obese NASH model (amylin liver NASH model [AMLN]), tropifexor markedly reduced steatohepatitis, fibrosis, and profibrogenic gene expression. Transcriptome analysis of livers from AMLN mice revealed 461 differentially expressed genes following tropifexor treatment that included a combination of signatures associated with reduction of oxidative stress, fibrogenesis, and inflammation. Conclusion: Based on preclinical validation in animal models, tropifexor is a promising investigational therapy that is currently under phase 2 development for NASH.

Guide Swap enables genome-scale pooled CRISPR-Cas9 screening in human primary cells

CRISPR-Cas9 screening allows genome-wide interrogation of gene function. Currently, to achieve the high and uniform Cas9 expression desirable for screening, one needs to engineer stable and clonal Cas9-expressing cells-an approach that is not applicable in human primary cells. Guide Swap permits genome-scale pooled CRISPR-Cas9 screening in human primary cells by exploiting the unexpected finding that editing by lentivirally delivered, targeted guide RNAs (gRNAs) occurs efficiently when Cas9 is introduced in complex with nontargeting gRNA. We validated Guide Swap in depletion and enrichment screens in CD4+ T cells. Next, we implemented Guide Swap in a model of ex vivo hematopoiesis, and identified known and previously unknown regulators of CD34+ hematopoietic stem and progenitor cell (HSPC) expansion. We anticipate that this platform will be broadly applicable to other challenging cell types, and thus will enable discovery in previously inaccessible but biologically relevant human primary cell systems.

Structure-guided combination therapy to potently improve the function of mutant CFTRs

Available corrector drugs are unable to effectively rescue the folding defects of CFTR-ΔF508 (or CFTR-F508del), the most common disease-causing mutation of the cystic fibrosis transmembrane conductance regulator, a plasma membrane (PM) anion channel, and thus to substantially ameliorate clinical phenotypes of cystic fibrosis (CF). To overcome the corrector efficacy ceiling, here we show that compounds targeting distinct structural defects of CFTR can synergistically rescue mutant expression and function at the PM. High-throughput cell-based screens and mechanistic analysis identified three small-molecule series that target defects at nucleotide-binding domain (NBD1), NBD2 and their membrane-spanning domain (MSD) interfaces. Although individually these compounds marginally improve ΔF508-CFTR folding efficiency, function and stability, their combinations lead to ~50-100% of wild-type-level correction in immortalized and primary human airway epithelia and in mouse nasal epithelia. Likewise, corrector combinations were effective against rare missense mutations in various CFTR domains, probably acting via structural allostery, suggesting a mechanistic framework for their broad application.

Synthesis of 3 H, 13 C2 , 2 H414 C-SCH 430765 and 35 S-SCH 500946, potent and selective inhibitors of the NPY5 receptor

SCH 430765 and SCH 500496 are potent and selective antagonists of the NPY₅ receptor. NPY₅ receptor antagonists have the potential for the treatment of obesity. [³⁵ S]SCH 500946 was prepared for a competition binding assay which led to the identification of SCH 430765. Three distinct isotopically labelled forms of SCH 430765 were synthesized. [³ H]SCH 430765 was prepared for a preliminary absorption, distribution, metabolism and excretion data evaluation of the compound and [¹⁴ C]SCH 430765 for more definitive absorption, distribution, metabolism and excretion data work. In addition, [¹³ C₂ ,² H₄ ]SCH 430765 was prepared as an internal standard for a LC-MS bioanalytical method. The paper discusses the synthesis of 3 isotopically labelled forms of SCH 430765 and [³⁵ S]SCH 500946.

Discovery of Tropifexor (LJN452), a Highly Potent Non-bile Acid FXR Agonist for the Treatment of Cholestatic Liver Diseases and Nonalcoholic Steatohepatitis (NASH)

The farnesoid X receptor (FXR) is a nuclear receptor that acts as a master regulator of bile acid metabolism and signaling. Activation of FXR inhibits bile acid synthesis and increases bile acid conjugation, transport, and excretion, thereby protecting the liver from the harmful effects of bile accumulation, leading to considerable interest in FXR as a therapeutic target for the treatment of cholestasis and nonalcoholic steatohepatitis. We identified a novel series of highly potent non-bile acid FXR agonists that introduce a bicyclic nortropine-substituted benzothiazole carboxylic acid moiety onto a trisubstituted isoxazole scaffold. Herein, we report the discovery of 1 (tropifexor, LJN452), a novel and highly potent agonist of FXR. Potent in vivo activity was demonstrated in rodent PD models by measuring the induction of FXR target genes in various tissues. Tropifexor has advanced into phase 2 human clinical trials in patients with NASH and PBC.

Synthesis of 3 H, 2 H4 , and 14 C-MK 3814 (preladenant)

MK 3814 is a potent and selective antagonist of the A_2a receptor. A_2a receptor antagonists have the potential for the treatment of Parkinson disease. Three distinct isotopically labelled forms of MK 3814 were synthesized. [³ H]MK 3814 was prepared for a preliminary absorption, distribution, metabolism, and excretion data (ADME) evaluation of the compound and [¹⁴ C]MK 3814 for more definitive ADME work, including an absorption, metabolism, and excretion study in man. In addition, [² H₄ ]MK 3814 was prepared as an internal standard for a liquid chromatography mass spectrometry bioanalytical method. This paper discusses the synthesis of 3 isotopically labelled forms of MK 3814.

Synthesis of (3) H, (2) H4 and (14) C-SCH 417690 (Vicriviroc)

Vicriviroc or SCH 417690 is a potent and selective antagonist of the CCR5 receptor. CCR5 receptor antagonists have the potential for the treatment of HIV infections. Four distinct isotopically labelled forms of SCH 417690 were synthesized. Low specific activity [(3) H]SCH 417690 was prepared for a preliminary absorption, distribution, metabolism and excretion evaluation of the compound and [(14) C]SCH 417690 for more definitive absorption, distribution, metabolism and excretion work, including an absorption, metabolism and excretion study in man. In addition, high specific activity [(3) H]SCH 417690 was prepared for CCR5 receptor binding work and [(2) H4 ]SCH 417690 was prepared as an internal standard for a liquid chromatography-mass spectrometry bioanalytical method. The paper discusses the synthesis of four isotopically labelled forms of SCH 417690.

Abstract IA35: Discovery of porcupine inhibitors targeting Wnt signaling in cancer

Wnt signaling is tightly controlled during cellular proliferation, differentiation and embryonic morphogenesis. Aberrant activation of this pathway plays a critical role in a variety of cancers. Blockade of Wnt signaling is therefore an attractive therapeutic approach for anticancer therapy. In this presentation, we will discuss our approach to search for inhibitors of Wnt ligand secretion. We developed and performed a cellular high-throughput screen using a co-culture system. Lead structure (GNF-1331) was identified and further target elucidation revealed Porcupine, a membrane bound O-acyl transferase, as its molecular target. Further structure-activity relationship studies led to the discovery of WNT974, a potent and specific Porcupine inhibitor. Treatment of WNT974 leads to tumor regression in a Wnt dependent MMTV-Wnt1 mouse model at well tolerated doses. WNT974 is currently in Phase 1 clinical trials.

Citation Format: Shifeng Pan, Jun Liu, Dai Cheng, Dong Han, Guobao Zhang, Mindy Hsieh, Nicholas Ng, Chun Li, Shailaja Kasibhatla, Peter McNamara, H. Martin Seidel, Jennifer Harris. Discovery of porcupine inhibitors targeting Wnt signaling in cancer. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr IA35.

Inhibition of DYRK1A and GSK3B induces human β-cell proliferation

Insufficient pancreatic β-cell mass or function results in diabetes mellitus. While significant progress has been made in regulating insulin secretion from β-cells in diabetic patients, no pharmacological agents have been described that increase β-cell replication in humans. Here we report aminopyrazine compounds that stimulate robust β-cell proliferation in adult primary islets, most likely as a result of combined inhibition of DYRK1A and GSK3B. Aminopyrazine-treated human islets retain functionality in vitro and after transplantation into diabetic mice. Oral dosing of these compounds in diabetic mice induces β-cell proliferation, increases β-cell mass and insulin content, and improves glycaemic control. Biochemical, genetic and cell biology data point to Dyrk1a as the key molecular target. This study supports the feasibility of treating diabetes with an oral therapy to restore β-cell mass, and highlights a tractable pathway for future drug discovery efforts.

Abstract 957: The ALK inhibitor LDK378 overcomes crizotinib resistance in non-small cell lung cancer

Non-small cell lung cancers (NSCLC) harboring anaplastic lymphoma kinase (ALK) gene rearrangements are sensitive to the ALK tyrosine kinase inhibitor (TKI) crizotinib. However, these cancers invariably relapse due to the development of resistance, and approximately 1/3 of such cancers develop resistance mutations within the ALK tyrosine kinase domain. Here we report the preclinical evaluation of the next-generation ALK TKI, LDK378 in the setting of crizotinib resistance. Using EML4-ALK mutant Ba/F3 cellular models, in vivo models of acquired resistance to crizotinib, and novel cell lines established from biopsies of crizotinib-resistant NSCLC patients, we have examined the efficacy of LDK378 in crizotinib-naïve and -resistant ALK-positive cancers. These studies reveal that LDK378 is more potent than crizotinib and effectively overcomes resistance in vitro and in vivo. In particular, LDK378 inhibits ALK harboring crizotinib resistance mutations, including L1196M, G1269A, I1171T and S1206Y. Cell lines derived from crizotinib-resistant biopsies were sensitive to LDK378, including one that did not harbor an ALK resistance mutation and was also sensitive to crizotinib, suggesting that some crizotinib-resistant cancers with wildtype ALK are still sensitive to complete ALK inhibition. We observed that LDK378 did not effectively overcome two crizotinib-resistant ALK mutations, G1202R and F1174C

ALK, and mutations in one of these residues was identified in 5 out of 11 biopsies from patients with acquired resistance to LDK378. Altogether our results demonstrate that LDK378 can overcome many mechanisms of crizotinib resistance, consistent with emerging clinical data showing marked efficacy of LDK378 in patients with crizotinib-resistant disease.

Citation Format: Luc Friboulet, Nanxin Li, Ryohei Katayama, Christian C. Lee, Justin F. Gainor, Adam S. Crystal, Pierre-Yves Michellys, Mark M. Awad, Noriko Yanagitani, Sungjoon Kim, AnneMarie Pferdekamper, Jie Li, Shailaja Kasibhatla, Frank Sun, Xiuying Sun, Su Hua, Peter McNamara, Sidra Mahmood, Elizabeth L. Lockerman, Naoya Fujita, Makoto Nishio, Jennifer L. Harris, Alice T. Shaw, Jeffrey A. Engelman. The ALK inhibitor LDK378 overcomes crizotinib resistance in non-small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 957. doi:10.1158/1538-7445.AM2014-957

The ALK inhibitor ceritinib overcomes crizotinib resistance in non-small cell lung cancer

Non-small cell lung cancers (NSCLC) harboring anaplastic lymphoma kinase (ALK) gene rearrangements invariably develop resistance to the ALK tyrosine kinase inhibitor (TKI) crizotinib. Herein, we report the first preclinical evaluation of the next-generation ALK TKI, ceritinib (LDK378), in the setting of crizotinib resistance. An interrogation of in vitro and in vivo models of acquired resistance to crizotinib, including cell lines established from biopsies of patients with crizotinib-resistant NSCLC, revealed that ceritinib potently overcomes crizotinib-resistant mutations. In particular, ceritinib effectively inhibits ALK harboring L1196M, G1269A, I1171T, and S1206Y mutations, and a cocrystal structure of ceritinib bound to ALK provides structural bases for this increased potency. However, we observed that ceritinib did not overcome two crizotinib-resistant ALK mutations, G1202R and F1174C, and one of these mutations was identified in 5 of 11 biopsies from patients with acquired resistance to ceritinib. Altogether, our results demonstrate that ceritinib can overcome crizotinib resistance, consistent with clinical data showing marked efficacy of ceritinib in patients with crizotinib-resistant disease.

SIGNIFICANCE

The second-generation ALK inhibitor ceritinib can overcome several crizotinib-resistant mutations and is potent against several in vitro and in vivo laboratory models of acquired resistance to crizotinib. These findings provide the molecular basis for the marked clinical activity of ceritinib in patients with ALK-positive NSCLC with crizotinib-resistant disease. Cancer Discov; 4(6); 662-73. ©2014 AACR. See related commentary by Ramalingam and Khuri, p. 634 This article is highlighted in the In This Issue feature, p. 621.

IL-2 immunotherapy reveals potential for innate beta cell regeneration in the non-obese diabetic mouse model of autoimmune diabetes

Type-1 diabetes (T1D) is an autoimmune disease targeting insulin-producing beta cells, resulting in dependence on exogenous insulin. To date, significant efforts have been invested to develop immune-modulatory therapies for T1D treatment. Previously, IL-2 immunotherapy was demonstrated to prevent and reverse T1D at onset in the non-obese diabetic (NOD) mouse model, revealing potential as a therapy in early disease stage in humans. In the NOD model, IL-2 deficiency contributes to a loss of regulatory T cell function. This deficiency can be augmented with IL-2 or antibody bound to IL-2 (Ab/IL-2) therapy, resulting in regulatory T cell expansion and potentiation. However, an understanding of the mechanism by which reconstituted regulatory T cell function allows for reversal of diabetes after onset is not clearly understood. Here, we describe that Ab/IL-2 immunotherapy treatment, given at the time of diabetes onset in NOD mice, not only correlated with reversal of diabetes and expansion of Treg cells, but also demonstrated the ability to significantly increase beta cell proliferation. Proliferation appeared specific to Ab/IL-2 immunotherapy, as anti-CD3 therapy did not have a similar effect. Furthermore, to assess the effect of Ab/IL-2 immunotherapy well after the development of diabetes, we tested the effect of delaying treatment for 4 weeks after diabetes onset, when beta cells were virtually absent. At this late stage after diabetes onset, Ab/IL-2 treatment was not sufficient to reverse hyperglycemia. However, it did promote survival in the absence of exogenous insulin. Proliferation of beta cells could not account for this improvement as few beta cells remained. Rather, abnormal insulin and glucagon dual-expressing cells were the only insulin-expressing cells observed in islets from mice with established disease. Thus, these data suggest that in diabetic NOD mice, beta cells have an innate capacity for regeneration both early and late in disease, which is revealed through IL-2 immunotherapy.

Limitations to the identification of HIV-associated neurocognitive disorders in clinical practice

OBJECTIVES

The objective of this study was to establish the level of awareness of HAND among healthcare providers, the screening tools that are currently used in its detection and factors that limit cognitive assessments.

METHODS

We distributed a 12-item questionnaire to doctors and nurses who work in the Department of Genitourinary Medicine and Infectious Disease (GUIDE) service and also to doctors who work in the emergency department (ED) at St James Hospital.

RESULTS

35 surveys were collected, 54% (n = 19) from the GUIDE service and 46% (n = 16) from the ED. 82% (n = 29) of participants were doctors from interns to consultants. There was reasonable appreciation among participants with regards the prevalence of neurocognitive impairment (estimated at 29.1% among patients on HAART, and 39.3% among patients not on HAART). Screening tools were rarely used by GUIDE and ED clinicians (25% vs. 15% of the time). The Mini Mental State Examination (MMSE) was previously used by 37% (n = 13) of the group. Very few people had used the HIV Dementia Scale (HIVDS) 6% (n = 2). 34% of respondents felt that 'Orientation in Person, Place and Time was a sufficient screening tool for cognitive assessment'. Lack of time, exposed environment and lack of availability of screening tool were cited as limitations to cognitive screening in the ED environment.

CONCLUSIONS

This study examines awareness of HAND among healthcare providers and also reasons for inadequate assessment. There is a need for consensus on screening guidelines. A quick, easy to use and readily available screening tool may have a role in the acute setting in identifying high-risk patients.

Small-molecule inducer of β cell proliferation identified by high-throughput screening

The identification of factors that promote β cell proliferation could ultimately move type 1 diabetes treatment away from insulin injection therapy and toward a cure. We have performed high-throughput, cell-based screens using rodent β cell lines to identify molecules that induce proliferation of β cells. Herein we report the discovery and characterization of WS6, a novel small molecule that promotes β cell proliferation in rodent and human primary islets. In the RIP-DTA mouse model of β cell ablation, WS6 normalized blood glucose and induced concomitant increases in β cell proliferation and β cell number. Affinity pulldown and kinase profiling studies implicate Erb3 binding protein-1 and the IκB kinase pathway in the mechanism of action of WS6.

Bilateral brachial neuritis secondary to varicella reactivation in an HIV-positive man

We present the case of a 48-year-old HIV-positive man, who developed acute onset of pain in both upper limbs associated with proximal weakness and distal paraesthesia. Eight weeks prior to this presentation he had had varicella zoster affecting his right S1 dermatome. CD4 count was 355 cells/mm(3) and he was antiretroviral therapy (ART) naive. Power was 0/5 proximally and 4/5 distally in the upper limbs. Reflexes were absent and there was sensory loss in the C5, C6 and T1 dermatomes. Cerebrospinal fluid (CSF) examination showed a lymphocytosis with low glucose; however, CSF Mycobacterium tuberculosis (TB), and herpes simplex virus polymerase chain reaction (HSV PCR) were negative as was syphilis serology. Electromyography showed marked motor axonal loss. Magnetic resonance imaging (MRI) did not show any cervical spinal lesion. Varicella zoster virus (VZV) PCR was positive in the CSF. He was treated with high-dose intravenous aciclovir with good resolution of his syndrome over time and was commenced on ART. We believe this to be the first case report of varicella reactivation causing bilateral neuralgic amyotrophy in an HIV-positive patient.

The case for cognitive screening in HIV clinics

A retrospective chart review was carried out at the HIV clinic in St. James's Hospital, Dublin to examine the rate of cognitive impairment through the use of surrogate markers for cognitive impairment. 500 consecutive hospital charts were reviewed. There were 306 men and 194 women. Median age was 37. The most common mode of transmission was heterosexual. 45% had a nadir CD4 < 200. 78.6% were on antiretroviral therapy and 72.26% were virally suppressed. 69/500 patients (13.8%) had one or more positive surrogate markers for cognitive impairment. The surrogate markers used were subjective complaints, a new onset of a psychiatric diagnosis post diagnosis with HIV, neurological complications and radiological evidence of atrophy. Multivariate analysis using logistic regression showed significant relationships only with gender and year of diagnosis. This figure is lower than reported international prevalence rates of cognitive impairment and demonstrates that surrogate markers are no match for structured cognitive screening. We have since commenced structured prospective screening to obtain a true prevalence of cognitive impairment in this population.

Characterization of a novel, brain-penetrating CB1 receptor inverse agonist: metabolic profile in diet-induced obese models and aspects of central activity

Pharmacologic antagonism of cannabinoid 1 receptors (CB1 receptors) in the central nervous system (CNS) suppresses food intake, promotes weight loss, and improves the metabolic profile. Since the CB1 receptor is expressed both in the CNS and in peripheral tissues, therapeutic value may be gained with CB1 receptor inverse agonists acting on receptors in both domains. The present report examines the metabolic and CNS actions of a novel CB1 receptor inverse agonist, compound 64, a 1,5,6-trisubstituted pyrazolopyrimidinone. Compound 64 showed similar or superior binding affinity, in vitro potency, and pharmacokinetic profile compared to rimonabant. Both compounds improved the metabolic profile in diet-induced obese (DIO) rats and obese cynomolgus monkeys. Weight loss tended to be greater in compound 64-treated DIO rats compared to pair-fed counterparts, suggesting that compound 64 may have metabolic effects beyond those elicited by weight loss alone. In the CNS, reversal of agonist-induced hypothermia and hypolocomotion indicated that compound 64 possessed an antagonist activity in vivo. Dosed alone, compound 64 suppressed extinction of conditioned freezing (10 mg/kg) and rapid eye movement (REM) sleep (30 mg/kg), consistent with previous reports for rimonabant, although for REM sleep, compound 64 was greater than threefold less potent than for metabolic effects. Together, these data suggested that (1) impairment of extinction learning and REM sleep suppression are classic, centrally mediated responses to CB1 receptor inverse agonists, and (2) some separation may be achievable between central and peripheral effects with brain-penetrating CB1 receptor inverse agonists while maintaining metabolic efficacy. Furthermore, chronic treatment with compound 64 contributes to evidence that peripheral CB1 receptor blockade may yield beneficial outcomes that exceed those elicited by weight loss alone.

Sleep in Parkinson's disease: a comparison of actigraphy and subjective measures

Sleep disturbances are common in Parkinson's disease (PD). Actigraphy has emerged as an alternative to polysomnography to measure sleep, raising the question of its ability to capture sleep quality in PD patients. Our aim was to compare self-report data with actigraphic data. Thirty non-demented individuals with PD and 14 normal control participants (NC) were included. Sleep was measured using 24-h wrist actigraphy over a seven day period, during which time participants kept a sleep diary. Subjective sleep and arousal questionnaires included the Parkinson's Disease Sleep Scale and Epworth Sleepiness Scale. Patients with PD presented with more sleep problems than NC. In NC, none of the actigraphic sleep variables were related to any of the self-report measures of sleep. In PD, scores on subjective sleep measures correlated with actigraphy-derived estimates of sleep quality. Our results suggest that actigraphy is an appropriate method of measuring sleep quality in PD.

Energetic constraints, not predation, influence the evolution of sleep patterning in mammals

Mammalian sleep is composed of two distinct states - rapid-eye-movement (REM) and non-REM (NREM) sleep - that alternate in cycles over a sleep bout. The duration of these cycles varies extensively across mammalian species. Because the end of a sleep cycle is often followed by brief arousals to waking, a shorter sleep cycle has been proposed to function as an anti-predator strategy. Similarly, higher predation risk could explain why many species exhibit a polyphasic sleep pattern (division of sleep into several bouts per day), as having multiple sleep bouts avoids long periods of unconsciousness, potentially reducing vulnerability.Using phylogenetic comparative methods, we tested these predictions in mammals, and also investigated the relationships among sleep phasing, sleep-cycle length, sleep durations and body mass.Neither sleep-cycle length nor phasing of sleep was significantly associated with three different measures of predation risk, undermining the idea that they represent anti-predator adaptations.Polyphasic sleep was associated with small body size, shorter sleep cycles and longer sleep durations. The correlation with size may reflect energetic constraints: small animals need to feed more frequently, preventing them from consolidating sleep into a single bout. The reduced daily sleep quotas in monophasic species suggests that the consolidation of sleep into one bout per day may deliver the benefits of sleep more efficiently and, since early mammals were small-bodied and polyphasic, a more efficient monophasic sleep pattern could be a hitherto unrecognized advantage of larger size.

A role for Alström syndrome protein, alms1, in kidney ciliogenesis and cellular quiescence

Premature truncation alleles in the ALMS1 gene are a frequent cause of human Alström syndrome. Alström syndrome is a rare disorder characterized by early obesity and sensory impairment, symptoms shared with other genetic diseases affecting proteins of the primary cilium. ALMS1 localizes to centrosomes and ciliary basal bodies, but truncation mutations in Alms1/ALMS1 do not preclude formation of cilia. Here, we show that in vitro knockdown of Alms1 in mice causes stunted cilia on kidney epithelial cells and prevents these cells from increasing calcium influx in response to mechanical stimuli. The stunted-cilium phenotype can be rescued with a 5′ fragment of the Alms1 cDNA, which resembles disease-associated alleles. In a mouse model of Alström syndrome, Alms1 protein can be stably expressed from the mutant allele and is required for cilia formation in primary cells. Aged mice developed specific loss of cilia from the kidney proximal tubules, which is associated with foci of apoptosis or proliferation. As renal failure is a common cause of mortality in Alström syndrome patients, we conclude that this disease should be considered as a further example of the class of renal ciliopathies: wild-type or mutant alleles of the Alström syndrome gene can support normal kidney ciliogenesis in vitro and in vivo, but mutant alleles are associated with age-dependent loss of kidney primary cilia.

Alström syndrome is a rare genetic disorder caused by mutations in the ALMS1 gene. The disease is characterized by blindness, deafness, and metabolic disorders. These symptoms are reminiscent of diseases affecting the primary cilium, a cellular appendage with a role in sensing changes to the extracellular environment. In addition, kidney failure is a frequent cause of death in Alström syndrome patients, and recent studies have suggested a causal relationship between defects in primary cilia and cystic kidney diseases. In this paper, we show that ALMS1 protein is required to form cilia in kidney cells. Mutant alleles of the gene that are similar to those seen in the human disease are able to support cilia formation in cell culture and in animals. However, a defect in the function of the disease alleles is uncovered in older mice: cilia are lost from the kidney cells, and this is associated with an increase in cellular proliferation and cell death. The data are consistent with a requirement for ALMS1 in ciliogenesis and suggest inclusion of Alström syndrome among the growing class of cilia-related pathologies.

Reporter metabolite analysis of transcriptional profiles of a Staphylococcus aureus strain with normal phenotype and its isogenic hemB mutant displaying the small-colony-variant phenotype

In this study, full-genome DNA microarrays based on the sequence of Staphylococcus aureus N315 were used to compare the transcriptome of a clinical S. aureus strain with a normal phenotype to that of its isogenic mutant with a stable small-colony-variant (SCV) phenotype (hemB::ermB). In addition to standard statistical analyses, systems biology advances were applied to identify reporter metabolites and to achieve a more detailed survey of genome-wide expression differences between the hemB mutant and its parental strain. Genes of enzymes involved in glycolytic and fermentative pathways were found to be up-regulated in the hemB mutant. Furthermore, our analyses allowed identification of additional differences between the normal-phenotype S. aureus and the SCV, most of which were related to metabolism. Profound differences were identified especially in purine biosynthesis as well as in arginine and proline metabolism. Of particular interest, a hypothetical gene of the Crp/Fnr family (SA2424) that is part of the arginine-deiminase (AD) pathway, whose homologue in Streptococcus suis is assumed to be involved in intracellular persistence, showed significantly increased transcription in the hemB mutant. The hemB mutant potentially uses the up-regulated AD pathway to produce ATP or (through ammonia production) to counteract the acidic environment that prevails intracellularly. Moreover, genes involved in capsular polysaccharide and cell wall synthesis were found to be significantly up-regulated in the hemB mutant and therefore potentially responsible for the changed cell morphology of SCVs. In conclusion, the identified differences may be responsible for the SCV phenotype and its association with chronic and persistent infections.