Fatty acid amide hydrolase (FAAH) is an integral membrane enzyme that degrades the fatty acid amide family of signaling lipids, including the endocannabinoid anandamide. Genetic or pharmacological ...inactivation of FAAH leads to analgesic, anti-inflammatory, anxiolytic, and antidepressant phenotypes in rodents without showing the undesirable side effects observed with direct cannabinoid receptor agonists, indicating that FAAH may represent an attractive therapeutic target for treatment of pain, inflammation, and other central nervous system disorders. However, the FAAH inhibitors reported to date lack drug-like pharmacokinetic properties and/or selectivity. Herein we describe piperidine/piperazine ureas represented by N-phenyl-4-(quinolin-3-ylmethyl)piperidine-1-carboxamide (PF-750) and N-phenyl-4-(quinolin-2-ylmethyl)piperazine-1-carboxamide (PF-622) as a novel mechanistic class of FAAH inhibitors. PF-750 and PF-622 show higher in vitro potencies than previously established classes of FAAH inhibitors. Rather unexpectedly based on the high chemical stability of the urea functional group, PF-750 and PF-622 were found to inhibit FAAH in a time-dependent manner by covalently modifying the enzyme's active site serine nucleophile. Activity-based proteomic profiling revealed that PF-750 and PF-622 were completely selective for FAAH relative to other mammalian serine hydrolases. We hypothesize that this remarkable specificity derives, at least in part, from FAAH's special ability to function as a C(O)−N bond hydrolase, which distinguishes it from the vast majority of metabolic serine hydrolases in mammals that are restricted to hydrolyzing esters and/or thioesters. The piperidine/piperazine urea may thus represent a privileged chemical scaffold for the synthesis of FAAH inhibitors that display an unprecedented combination of potency and selectivity for use as potential analgesic and anxiolytic/antidepressant agents.
The underlying causes of obesity are poorly understood but probably involve complex interactions between many neurotransmitter and neuropeptide systems involved in the regulation of food intake and ...energy balance. Three pieces of evidence indicate that the neuropeptide melanin-concentrating hormone (MCH) is an important component of this system. First, MCH stimulates feeding when injected directly into rat brains,; second, the messenger RNA for the MCH precursor is upregulated in the hypothalamus of genetically obese mice and in fasted animals; and third, mice lacking MCH eat less and are lean. MCH antagonists might, therefore, provide a treatment for obesity. However, the development of such molecules has been hampered because the identity of the MCH receptor has been unknown until now. Here we show that the 353-amino-acid human orphan G-protein-coupled receptor SLC-1 (ref. 4) expressed in HEK293 cells binds MCH with sub-nanomolar affinity, and is stimulated by MCH to mobilize intracellular Ca2+ and reduce forskolin-elevated cyclic AMP levels. We also show that SLC-1 messenger RNA and protein is expressed in the ventromedial and dorsomedial nuclei of the hypothalamus, consistent with a role for SLC-1 in mediating the effects of MCH on feeding.
Objectives
To describe the clinical epidemiology of COVID‐19 in people of black ethnicity living with HIV in the UK.
Methods
We investigated the incidence and factors associated with COVID‐19 in a ...previously established and well‐characterized cohort of black people with HIV. Primary outcomes were COVID‐19 acquisition and severe COVID‐19 disease (requiring hospitalization and/or resulting in death). Cumulative incidence was analysed using Nelson–Aalen methods, and associations between demographic, pre‐pandemic immune‐virological parameters, comorbidity status and (severe) COVID‐19 were identified using Cox regression analysis.
Results
COVID‐19 status was available for 1847 (74%) of 2495 COVID‐AFRICA participants (median age 49.6 years; 56% female; median CD4 cell count = 555 cells/μL; 93% HIV RNA <200 copies/mL), 573 (31%) of whom reported at least one episode of COVID‐19. The cumulative incidence rates of COVID‐19 and severe COVID‐19 were 31.0% and 3.4%, respectively. Region of ancestry (East/Southern/Central vs. West Africa), nadir CD4 count and kidney disease were associated with COVID‐19 acquisition. Diabetes mellitus adjusted hazard ratio (aHR) = 2.39, 95% confidence interval (CI): 1.26–4.53 and kidney disease (aHR = 2.53, 95% CI: 1.26–4.53) were associated with an increased risk, and recent CD4 count >500 cells/μL (aHR = 0.49, 95% CI: 0.25–0.93) with a lower risk of severe COVID‐19.
Conclusions
Region of ancestry was associated with COVID‐19 acquisition, and immune and comorbidity statuses were associated with COVID‐19 disease severity in people of black ethnicity living with HIV in the UK.
Using a genomics-based reverse pharmacological approach for screening orphan G-protein coupled receptors, we have identified and cloned a novel high-affinity histamine receptor. This receptor, termed ...AXOR35, is most closely related to the H3 histamine receptor, sharing 37% protein sequence identity. A multiple responsive element/cyclic AMP-responsive element-luciferase reporter assay was used to identify histamine as a ligand for AXOR35. When transfected into human embryonic kidney 293 cells, the AXOR35 receptor showed a strong, dose-dependent calcium mobilization response to histamine and H3 receptor agonists including imetit and immepip. Radioligand binding confirmed that the AXOR35 receptor was a high-affinity histamine receptor. The pharmacology of the AXOR35 receptor was found to closely resemble that of the H3 receptor; the major difference was that (R)-alpha-methylhistamine was a low potency agonist of the AXOR35 receptor. Thioperamide is an antagonist at AXOR 35. Expression of AXOR35 mRNA in human tissues is highest in peripheral blood mononuclear cells and in tissues likely to contain high concentrations of blood cells, such as bone marrow and lung. In situ hybridization analysis of a wide survey of mouse tissues showed that mouse AXOR35 mRNA is selectively expressed in hippocampus. The identification and localization of this new histamine receptor will expand our understanding of the physiological and pathological roles of histamine and may provide additional opportunities for pharmacological modification of these actions.
Opiate tolerance and dependence are major clinical and social problems. The anti-opiate neuropeptides FF and AF (NPFF and NPAF) have been implicated in pain modulation as well as in opioid tolerance ...and may play a critical role in this process, although their mechanism of action has remained unknown. Here we describe a cDNA encoding a novel neuropeptide Y-like human orphan G protein-coupled receptor (GPCR), referred to as HLWAR77 for which NPAF and NPFF have high affinity. Cells transiently or stably expressing HLWAR77 bind and respond in a concentration-dependent manner to NPAF and NPFF and are also weakly activated by FMRF-amide (Phe-Met-Arg-Phe-amide) and a variety of related peptides. The high affinity and potency of human NPFF and human NPAF for HLWAR77 strongly suggest that these are the cognate ligands for this receptor. Expression of HLWAR77 was demonstrated in brain regions associated with opiate activity, consistent with the pain-modulating activity of these peptides, whereas the expression in adipose tissue suggests other physiological and pathophysiological activities for FMRF-amide neuropeptides. The discovery that the anti-opiate neuropeptides are the endogenous ligands for HLWAR77 will aid in defining the physiological role(s) of these ligands and facilitate the identification of receptor agonists and antagonists.
Neuromedins are a family of peptides best known for their contractile activity on smooth muscle preparations. The biological mechanism of action of neuromedin U remains unknown, despite the fact that ...the peptide was first isolated in 1985. Here we show that neuromedin U potently activates the orphan G protein-coupled receptor FM3, with subnanomolar potency, when FM3 is transiently expressed in human HEK-293 cells. Neuromedins B, C, K, and N are all inactive at this receptor. Quantitative reverse transcriptase-polymerase chain reaction analysis of neuromedin U expression in a range of human tissues showed that the peptide is highly expressed in the intestine, pituitary, and bone marrow, with lower levels of expression seen in stomach, adipose tissue, lymphocytes, spleen, and the cortex. Similar analysis of FM3 expression showed that the receptor is widely expressed in human tissue with highest levels seen in adipose tissue, intestine, spleen, and lymphocytes, suggesting that neuromedin U may have a wide range of presently undetermined physiological effects. The discovery that neuromedin U is an endogenous agonist for FM3 will significantly aid the study of the full physiological role of this peptide.
The ligand-gated ion channel family includes receptors for serotonin (5-hydroxytryptamine, 5-HT), acetylcholine, GABA, and glutamate. Drugs targeting subtypes of these receptors have proven useful ...for the treatment of various neuropsychiatric and neurological disorders. To identify new ligand-gated ion channels as potential therapeutic targets, drafts of human genome sequence were interrogated. Portions of four novel genes homologous to 5-HT
3A and 5-HT
3B receptors were identified within human sequence databases. We named the genes 5-HT
3C1–5-HT
3C4. Radiation hybrid (RH) mapping localized these genes to chromosome 3q27–28. All four genes shared similar intron–exon organizations and predicted protein secondary structure with 5-HT
3A and 5-HT
3B. Orthologous genes were detected by Southern blotting in several species including dog, cow, and chicken, but not in rodents, suggesting that these novel genes are not present in rodents or are very poorly conserved. Two of the novel genes are predicted to be pseudogenes, but two other genes are transcribed and spliced to form appropriate open reading frames. The 5-HT
3C1 transcript is expressed almost exclusively in small intestine and colon, suggesting a possible role in the serotonin-responsiveness of the gut.
A series of aminomethylpyrazoles were prepared and evaluated using cell-based Smoothened β-lactamase reporter assay and Smoothened binding assay. Potent Smoothened antagonists
10k and
10l were found ...to inhibit hair growth in vivo in the C3H/HeN mouse hair growth model. The more selective compound
10l was tested negative in the 3T3 NRU assay, indicating a low risk for causing photo-irritation and was efficacious using the C3H/HeN mouse hair growth model although it was slightly less efficacious than that of the reference compound eflornithine (
7).
A series of aminomethylpyrazoles were prepared and evaluated using cell-based Smoothened β-lactamase reporter assay and Smoothened binding assay. Potent Smoothened antagonists
10k and
10l were found to inhibit hair growth in vivo in the C3H/HeN mouse hair growth model. The more selective compound
10l was tested negative in the 3T3 NRU assay, indicating a low risk for causing photo-irritation and was efficacious using the C3H/HeN mouse hair growth model although it was slightly less efficacious than that of the reference compound eflornithine (
7).
Extracorporeal membrane oxygenation (ECMO) has been used successfully to support adults with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related cardiac or respiratory failure ...refractory to conventional therapies. Comprehensive reports of children and adolescents with SARS-CoV-2-related ECMO support for conditions, including multisystem inflammatory syndrome in children (MIS-C) and acute COVID-19, are needed.
Case series of patients from the Overcoming COVID-19 public health surveillance registry.
Sixty-three hospitals in 32 U.S. states reporting to the registry between March 15, 2020, and December 31, 2021.
Patients less than 21 years admitted to the ICU meeting Centers for Disease Control criteria for MIS-C or acute COVID-19.
None.
The final cohort included 2,733 patients with MIS-C ( n = 1,530; 37 2.4% requiring ECMO) or acute COVID-19 ( n = 1,203; 71 5.9% requiring ECMO). ECMO patients in both groups were older than those without ECMO support (MIS-C median 15.4 vs 9.9 yr; acute COVID-19 median 15.3 vs 13.6 yr). The body mass index percentile was similar in the MIS-C ECMO versus no ECMO groups (89.9 vs 85.8; p = 0.22) but higher in the COVID-19 ECMO versus no ECMO groups (98.3 vs 96.5; p = 0.03). Patients on ECMO with MIS-C versus COVID-19 were supported more often with venoarterial ECMO (92% vs 41%) for primary cardiac indications (87% vs 23%), had ECMO initiated earlier (median 1 vs 5 d from hospitalization), shorter ECMO courses (median 3.9 vs 14 d), shorter hospital length of stay (median 20 vs 52 d), lower in-hospital mortality (27% vs 37%), and less major morbidity at discharge in survivors (new tracheostomy, oxygen or mechanical ventilation need or neurologic deficit; 0% vs 11%, 0% vs 20%, and 8% vs 15%, respectively). Most patients with MIS-C requiring ECMO support (87%) were admitted during the pre-Delta (variant B.1.617.2) period, while most patients with acute COVID-19 requiring ECMO support (70%) were admitted during the Delta variant period.
ECMO support for SARS-CoV-2-related critical illness was uncommon, but type, initiation, and duration of ECMO use in MIS-C and acute COVID-19 were markedly different. Like pre-pandemic pediatric ECMO cohorts, most patients survived to hospital discharge.
The seven-transmembrane protein Smoothened (Smo) mediates the cellular response to the Hedgehog protein signal and is involved in cell growth and differentiation during embryonic development. ...Stimulation of the Smo pathway is directly implicated in tissue maintenance and repair, but overactivation of Smo could lead to tumorigenesis. We developed a robust and sensitive functional cell-based assay that measures the activity of endogenous Smo using a beta-lactamase transcriptional readout. This is the first Smo reporter assay that utilizes beta-lactamase reporter technology. This assay type has distinct advantages over other reporter technologies and can be used in a high-throughput mode to search for therapeutically relevant downstream Smo target effectors.
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