Sex differences in activation of extra-hypothalamic forebrain areas during hedonic eating.

Palatable foods can stimulate appetite without hunger, and unconstrained overeating underlies obesity and binge eating disorder. Women are more prone to obesity and binge eating than men but the neural causes of individual differences are unknown. In an animal model of hedonic eating, a prior study found that females were more susceptible than males to eat palatable food when sated and that the neuropeptide orexin/hypocretin (ORX) was crucial in both sexes. The current study examined potential extra-hypothalamic forebrain targets of ORX signaling during hedonic eating. We measured Fos induction in the cortical, thalamic, striatal, and amygdalar areas that receive substantial ORX inputs and contain their receptors in hungry and sated male and female rats during palatable (high-sucrose) food consumption. During the test, hungry rats of both sexes ate substantial amounts, and while sated males ate much less than hungry rats, sated females ate as much as hungry rats. The Fos induction analysis identified sex differences in recruitment of specific areas of the medial prefrontal cortex, paraventricular nucleus of the thalamus (PVT), nucleus accumbens (ACB), and central nucleus of the amygdala (CEA), and similar patterns across sexes in the insular cortex. There was a striking activation of the infralimbic cortex in sated males, who consumed the least amount food and unique correlations between the insular cortex, PVT, and CEA, as well as the prelimbic cortex, ACB, and CEA in sated females but not sated males. The study identified key functional circuits that may drive hedonic eating in a sex-specific manner.

Discovery of Potent and Selective Inhibitors against Protein-Derived Electrophilic Cofactors.

Electrophilic cofactors are widely distributed in nature and play important roles in many physiological and disease processes, yet they have remained blind spots in traditional activity-based protein profiling (ABPP) approaches that target nucleophiles. More recently, reverse-polarity (RP)-ABPP using hydrazine probes identified an electrophilic N-terminal glyoxylyl (Glox) group for the first time in secernin-3 (SCRN3). The biological function(s) of both the protein and Glox as a cofactor has not yet been pharmacologically validated because of the lack of selective inhibitors that could disrupt and therefore identify its activity. Here, we present the first platform for analyzing the reactivity and selectivity of an expanded nucleophilic probe library toward main-chain carbonyl cofactors such as Glox and pyruvoyl (Pyvl) groups. We first applied the library proteome-wide to profile and confirm engagement with various electrophilic protein targets, including secernin-2 (SCRN2), shown here also to possess a Glox group. A broadly reactive indole ethylhydrazine probe was used for a competitive in vitro RP-ABPP assay to screen for selective inhibitors against such cofactors from a set of commercially available nucleophilic fragments. Using Glox-containing SCRN proteins as a case study, naphthyl hydrazine was identified as a potent and selective SCRN3 inhibitor, showing complete inhibition in cell lysates with no significant cross-reactivity detected for other enzymes. Moving forward, this platform provides the fundamental basis for the development of selective Glox inhibitors and represents a starting point to advance small molecules that modulate electrophile-dependent function.

Activity-Based Hydrazine Probes for Protein Profiling of Electrophilic Functionality in Therapeutic Targets.

Most known probes for activity-based protein profiling (ABPP) use electrophilic groups that tag a single type of nucleophilic amino acid to identify cases in which its hyper-reactivity underpins function. Much important biochemistry derives from electrophilic enzyme cofactors, transient intermediates, and labile regulatory modifications, but ABPP probes for such species are underdeveloped. Here, we describe a versatile class of probes for this less charted hemisphere of the proteome. The use of an electron-rich hydrazine as the common chemical modifier enables covalent targeting of multiple, pharmacologically important classes of enzymes bearing diverse organic and inorganic cofactors. Probe attachment occurs by both polar and radicaloid mechanisms, can be blocked by molecules that occupy the active sites, and depends on the proper poise of the active site for turnover. These traits will enable the probes to be used to identify specific inhibitors of individual members of these multiple enzyme classes, making them uniquely versatile among known ABPP probes.

Development of succinimide-based inhibitors for the mitochondrial rhomboid protease PARL.

While the biochemistry of rhomboid proteases has been extensively studied since their discovery two decades ago, efforts to define the physiological roles of these enzymes are ongoing and would benefit from chemical probes that can be used to manipulate the functions of these proteins in their native settings. Here, we describe the use of activity-based protein profiling (ABPP) technology to conduct a targeted screen for small-molecule inhibitors of the mitochondrial rhomboid protease PARL, which plays a critical role in regulating mitophagy and cell death. We synthesized a series of succinimide-containing sulfonyl esters and sulfonamides and discovered that these compounds serve as inhibitors of PARL with the most potent sulfonamides having submicromolar affinity for the enzyme. A counterscreen against the bacterial rhomboid protease GlpG demonstrates that several of these compounds display selectivity for PARL over GlpG by as much as two orders of magnitude. Both the sulfonyl ester and sulfonamide scaffolds exhibit reversible binding and are able to engage PARL in mammalian cells. Collectively, our findings provide encouraging precedent for the development of PARL-selective inhibitors and establish N-[(arylsulfonyl)oxy]succinimides and N-arylsulfonylsuccinimides as new molecular scaffolds for inhibiting members of the rhomboid protease family.

Children are more forgiving of accidental harms across development.

Forgiveness is a powerful feature of human social life, allowing for the restoration of positive cooperative relationships. Despite its importance, we know relatively little about how forgiveness develops during early life and the features that shape forgiveness decisions. Here, we investigated forgiveness behavior in children aged 5-10 years (N = 257) from the United States, varying transgressor intent and remorse in a behavioral task that pitted punishment against forgiveness. We found that baseline levels of forgiveness are high, suggesting that children assume the best of transgressors in the absence of information about intent and remorse. We also found age-related increases in sensitivity to intent but not remorse, such that older children are more likely to forgive accidental transgressions. Because forgiveness is an important tool in the human social toolkit, exploring the ways in which this ability develops across age can help us to better understand the early roots of human cooperation.

AIG1 and ADTRP are endogenous hydrolases of fatty acid esters of hydroxy fatty acids (FAHFAs) in mice.

Fatty acid esters of hydroxy fatty acids (FAHFAs) are a newly discovered class of signaling lipids with anti-inflammatory and anti-diabetic properties. However, the endogenous regulation of FAHFAs remains a pressing but unanswered question. Here, using MS-based FAHFA hydrolysis assays, LC-MS-based lipidomics analyses, and activity-based protein profiling, we found that androgen-induced gene 1 (AIG1) and androgen-dependent TFPI-regulating protein (ADTRP), two threonine hydrolases, control FAHFA levels in vivo in both genetic and pharmacologic mouse models. Tissues from mice lacking ADTRP (Adtrp-KO), or both AIG1 and ADTRP (DKO) had higher concentrations of FAHFAs particularly isomers with the ester bond at the 9th carbon due to decreased FAHFA hydrolysis activity. The levels of other lipid classes were unaltered indicating that AIG1 and ADTRP specifically hydrolyze FAHFAs. Complementing these genetic studies, we also identified a dual AIG1/ADTRP inhibitor, ABD-110207, which is active in vivo Acute treatment of WT mice with ABD-110207 resulted in elevated FAHFA levels, further supporting the notion that AIG1 and ADTRP activity control endogenous FAHFA levels. However, loss of AIG1/ADTRP did not mimic the changes associated with pharmacologically administered FAHFAs on extent of upregulation of FAHFA levels, glucose tolerance, or insulin sensitivity in mice, indicating that therapeutic strategies should weigh more on FAHFA administration. Together, these findings identify AIG1 and ADTRP as the first endogenous FAHFA hydrolases identified and provide critical genetic and chemical tools for further characterization of these enzymes and endogenous FAHFAs to unravel their physiological functions and roles in health and disease.

Pharmacological convergence reveals a lipid pathway that regulates C. elegans lifespan.

Phenotypic screening has identified small-molecule modulators of aging, but the mechanism of compound action often remains opaque due to the complexities of mapping protein targets in whole organisms. Here, we combine a library of covalent inhibitors with activity-based protein profiling to coordinately discover bioactive compounds and protein targets that extend lifespan in Caenorhabditis elegans. We identify JZL184-an inhibitor of the mammalian endocannabinoid (eCB) hydrolase monoacylglycerol lipase (MAGL or MGLL)-as a potent inducer of longevity, a result that was initially perplexing as C. elegans does not possess an MAGL ortholog. We instead identify FAAH-4 as a principal target of JZL184 and show that this enzyme, despite lacking homology with MAGL, performs the equivalent metabolic function of degrading eCB-related monoacylglycerides in C. elegans. Small-molecule phenotypic screening thus illuminates pure pharmacological connections marking convergent metabolic functions in distantly related organisms, implicating the FAAH-4/monoacylglyceride pathway as a regulator of lifespan in C. elegans.

Long-Term Intake of a High-Protein Diet Affects Body Phenotype, Metabolism, and Plasma Hormones in Mice.

Background: High-protein diets (HPDs) recently have been used to obtain body weight and fat mass loss and expand muscle mass. Several studies have documented that HPDs reduce appetite and food intake.Objective: Our goal was to determine the long-term effects of an HPD on body weight, energy intake and expenditure, and metabolic hormones.Methods: Male C57BL/6 mice (8 wk old) were fed either an HPD (60% of energy as protein) or a control diet (CD; 20% of energy as protein) for 12 wk. Body composition and food intakes were determined, and plasma hormone concentrations were measured in mice after being fed and after overnight feed deprivation at several time points.Results: HPD mice had significantly lower body weight (in means ± SEMs; 25.73 ± 1.49 compared with 32.5 ± 1.31 g; P = 0.003) and fat mass (9.55% ± 1.24% compared with 15.78% ± 2.07%; P = 0.05) during the first 6 wk compared with CD mice, and higher lean mass throughout the study starting at week 2 (85.45% ± 2.25% compared with 75.29% ± 1.90%; P = 0.0001). Energy intake, total energy expenditure, and respiratory quotient were significantly lower in HPD compared with CD mice as shown by cumulative energy intake and eating rate. Water vapor was significantly higher in HPD mice during both dark and light phases. In HPD mice, concentrations of leptin [feed-deprived: 41.31 ± 11.60 compared with 3041 ± 683 pg/mL (P = 0.0004); postprandial: 112.5 ± 102.0 compared with 8273 ± 1415 pg/mL (P < 0.0001)] and glucagon-like peptide 1 (GLP-1) [feed-deprived: 5.664 ± 1.44 compared with 21.31 ± 1.26 pg/mL (P = <0.0001); postprandial: 6.54 ± 2.13 compared with 50.62 ± 11.93 pg/mL (P = 0.0037)] were significantly lower, whereas postprandial glucagon concentrations were higher than in CD-fed mice.Conclusions: In male mice, the 12-wk HPD resulted in short-term body weight and fat mass loss, but throughout the study preserved body lean mass and significantly reduced energy intake and expenditure as well as leptin and GLP-1 concentrations while elevating postprandial glucagon concentrations. This study suggests that long-term use of HPDs may be an effective strategy to decrease energy intake and expenditure and to maintain body lean mass.

A Sodium Channel Myotonia Presenting with Intermittent Dysphagia as a Manifestation of a Rare SCN4A Variant.

The voltage gated sodium channel SCN4A mutations account for non-dystrophic myotonia and include a heterogeneous group of conditions that include hyperkalemic periodic paralysis, paramyotonica congenita, potassium-aggravated myotonia, and hypokalemic periodic paralysis type 2. This case report proposes that a rare variant p.Pro1629Leu in SCN4A can cause a skeletal muscle deficit with intermittent dysphagia.

Branched Fatty Acid Esters of Hydroxy Fatty Acids Are Preferred Substrates of the MODY8 Protein Carboxyl Ester Lipase.

A recently discovered class of endogenous mammalian lipids, branched fatty acid esters of hydroxy fatty acids (FAHFAs), possesses anti-diabetic and anti-inflammatory activities. Here, we identified and validated carboxyl ester lipase (CEL), a pancreatic enzyme hydrolyzing cholesteryl esters and other dietary lipids, as a FAHFA hydrolase. Variants of CEL have been linked to maturity-onset diabetes of the young, type 8 (MODY8), and to chronic pancreatitis. We tested the FAHFA hydrolysis activity of the CEL MODY8 variant and found a modest increase in activity as compared with that of the normal enzyme. Together, the data suggest that CEL might break down dietary FAHFAs.

A calcium-dependent acyltransferase that produces N-acyl phosphatidylethanolamines.

More than 30 years ago, a calcium-dependent enzyme activity was described that generates N-acyl phosphatidylethanolamines (NAPEs), which are precursors for N-acyl ethanolamine (NAE) lipid transmitters, including the endocannabinoid anandamide. The identity of this calcium-dependent N-acyltransferase (Ca-NAT) has remained mysterious. Here, we use activity-based protein profiling to identify the poorly characterized serine hydrolase PLA2G4E as a mouse brain Ca-NAT and show that this enzyme generates NAPEs and NAEs in mammalian cells.

AIG1 and ADTRP are atypical integral membrane hydrolases that degrade bioactive FAHFAs.

Enzyme classes may contain outlier members that share mechanistic, but not sequence or structural, relatedness with more common representatives. The functional annotation of such exceptional proteins can be challenging. Here, we use activity-based profiling to discover that the poorly characterized multipass transmembrane proteins AIG1 and ADTRP are atypical hydrolytic enzymes that depend on conserved threonine and histidine residues for catalysis. Both AIG1 and ADTRP hydrolyze bioactive fatty acid esters of hydroxy fatty acids (FAHFAs) but not other major classes of lipids. We identify multiple cell-active, covalent inhibitors of AIG1 and show that these agents block FAHFA hydrolysis in mammalian cells. These results indicate that AIG1 and ADTRP are founding members of an evolutionarily conserved class of transmembrane threonine hydrolases involved in bioactive lipid metabolism. More generally, our findings demonstrate how chemical proteomics can excavate potential cases of convergent or parallel protein evolution that defy conventional sequence- and structure-based predictions.

PACAP intraperitoneal treatment suppresses appetite and food intake via PAC1 receptor in mice by inhibiting ghrelin and increasing GLP-1 and leptin.

Pituitary adenylate cyclase-activating peptide (PACAP) is expressed within the gastroenteric system, where it has profound physiological effects. PACAP was shown to regulate food intake and thermogenesis centrally; however, PACAP peripheral regulation of appetite and feeding behavior is unknown. Therefore, we studied PACAP's effect on appetite and food intake control by analyzing feeding behavior and metabolic hormones in PAC1-deficient (PAC1-/-) and age-matched wild-type (WT) mice intraperitoneally injected with PACAP1-38 or PACAP1-27 before the dark phase of feeding. Food intake and feeding behavior were analyzed using the BioDAQ system. Active ghrelin, glucagon-like peptide-1 (GLP-1), leptin, peptide YY, pancreatic polypeptide, and insulin were measured following PACAP1-38 administration in fasted WT mice. PACAP1-38/PACAP1-27 injected into WT mice significantly decreased in a dose-dependent manner cumulative food intake and reduced bout and meal feeding parameters. Conversely, PACAP1-38 injected into PAC1-/- mice failed to significantly change food intake. Importantly, PACAP1-38 reduced plasma levels of active ghrelin compared with vehicle in WT mice. In PAC1-/- mice, fasting levels of active ghrelin, GLP-1, insulin, and leptin and postprandial levels of active ghrelin and insulin were significantly altered compared with levels in WT mice. Therefore, PAC1 is a novel regulator of appetite/satiety. PACAP1-38/PACAP1-27 significantly reduced appetite and food intake through PAC1. In PAC1-/- mice, the regulation of anorexigenic/orexigenic hormones was abolished, whereas active ghrelin remained elevated even postprandially. PACAP significantly reduced active ghrelin in fasting conditions. These results establish a role for PACAP via PAC1 in the peripheral regulation of appetite/satiety and suggest future studies to explore a therapeutic use of PACAP or PAC1 agonists for obesity treatment.

Benzo[d]imidazole Transient Receptor Potential Vanilloid 1 Antagonists for the Treatment of Pain: Discovery of trans-2-(2-{2-[2-(4-Trifluoromethyl-phenyl)-vinyl]-1H-benzimidazol-5-yl}-phenyl)-propan-2-ol (Mavatrep).

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. In a TRPV1 functional assay, using cells expressing recombinant human TRPV1 channels, 4 antagonized capsaicin-induced Ca(2+) influx, with an IC50 value of 4.6 nM. In the complete Freund's adjuvant- and carrageenan-induced thermal hypersensitivity models, 4 exhibited full efficacy, with ED80 values of 7.8 and 0.5 mg/kg, respectively, corresponding to plasma levels of 270.8 and 9.2 ng/mL, respectively. On the basis of its superior pharmacologic and safety profile, 4 (mavatrep) was selected for clinical development for the treatment of pain.

Morphological variations within the ontogeny of Deinonychus antirrhopus (Theropoda, Dromaeosauridae).

This research resulted from the determination that MCZ 8791 is a specimen of Deinonychus antirrhopus between one and two years of age and that the morphological variations within particular growth stages of this taxon have yet to be described. The primary goal of the research is to identify ontogenetic variations in this taxon. Histological analyses determined that the Deinonychus specimens AMNH 3015 and MOR 1178 were adults. Comparisons are made between MCZ 8791 and these adult specimens. The holotype, YPM 5205, and the other associated specimens of this taxon within the YPM collection are similar in size and morphology to AMNH 3015. Further comparisons were made with the three partial specimens OMNH 50268, MCZ 4371, and MOR 1182. Although these specimens represent only a partial ontogenetic series, a number of morphological variations can be described. One secondary goal of this research is to compare the known pattern of variable, informative, ontogenetic characters in MCZ 8791 to a similar pattern of morphological characters in the sub-adult dromaeosaurid specimen Bambiraptor feinbergorum, AMNH FR: 30556. If the characters that have been determined to represent variable juvenile morphology in the ontogeny of Deinonychus are exhibited in Bambiraptor, this study will begin the process of determining whether a similar, conservative, ontogenetic pattern exists throughout the rest of Dromaeosauridae. If defensible, it may reduce the number of sympatric taxa within this clade. The other secondary goal relates to the forelimb function. The approximate body size, forelimb length, wrist development, and the presence of a more prominent olecranon on the ulna of MCZ 8791 support the hypothesis that juveniles of this taxon possessed some form of flight capability.

Immunomodulatory lysophosphatidylserines are regulated by ABHD16A and ABHD12 interplay.

Lysophosphatidylserines (lyso-PSs) are a class of signaling lipids that regulate immunological and neurological processes. The metabolism of lyso-PSs remains poorly understood in vivo. Recently, we determined that ABHD12 is a major brain lyso-PS lipase, implicating lyso-PSs in the neurological disease polyneuropathy, hearing loss, ataxia, retinitis pigmentosa and cataract (PHARC), which is caused by null mutations in the ABHD12 gene. Here, we couple activity-based profiling with pharmacological and genetic methods to annotate the poorly characterized enzyme ABHD16A as a phosphatidylserine (PS) lipase that generates lyso-PS in mammalian systems. We describe a small-molecule inhibitor of ABHD16A that depletes lyso-PSs from cells, including lymphoblasts derived from subjects with PHARC. In mouse macrophages, disruption of ABHD12 and ABHD16A respectively increases and decreases both lyso-PSs and lipopolysaccharide-induced cytokine production. Finally, Abhd16a(-/-) mice have decreased brain lyso-PSs, which runs counter to the elevation in lyso-PS in Abhd12(-/-) mice. Our findings illuminate an ABHD16A-ABHD12 axis that dynamically regulates lyso-PS metabolism in vivo, designating these enzymes as potential targets for treating neuroimmunological disorders.

Saxitoxin.

The paralytic agent (+)-saxitoxin (STX), most commonly associated with oceanic red tides and shellfish poisoning, is a potent inhibitor of electrical conduction in cells. Its nefarious effects result from inhibition of voltage-gated sodium channels (Na(V)s), the obligatory proteins responsible for the initiation and propagation of action potentials. In the annals of ion channel research, the identification and characterization of Na(V)s trace to the availability of STX and an allied guanidinium derivative, tetrodotoxin. The mystique of STX is expressed in both its function and form, as this uniquely compact dication boasts more heteroatoms than carbon centers. This Review highlights both the chemistry and chemical biology of this fascinating natural product, and offers a perspective as to how molecular design and synthesis may be used to explore Na(V) structure and function.

A 18F-labeled saxitoxin derivative for in vivo PET-MR imaging of voltage-gated sodium channel expression following nerve injury.

Both chronic and neuropathic pain conditions are associated with increased expression of certain voltage-gated sodium ion channel (NaV) isoforms in peripheral sensory neurons. A method for noninvasive imaging of these channels could represent a powerful tool for investigating aberrant expression of NaV and its role in pain pathogenesis. Herein, we describe the synthesis and evaluation of a positron emission tomography (PET) radiotracer targeting NaVs, the design of which is based on the potent, NaV-selective inhibitor saxitoxin. Both autoradiography analysis of sciatic nerves excised from injured rats as well as whole animal PET-MR imaging demonstrate that a systemically administered [(18)F]-labeled saxitoxin derivative concentrates at the site of nerve injury, consistent with upregulated sodium channel expression following axotomy. This type of PET agent has potential use for serial monitoring of channel expression levels at injured nerves throughout wound healing and/or following drug treatment. Such information may be correlated with pain behavioral analyses to help shed light on the complex molecular processes that underlie pain sensation.

Maleimide conjugates of saxitoxin as covalent inhibitors of voltage-gated sodium channels.

(+)-Saxitoxin, a naturally occurring guanidinium poison, functions as a potent, selective, and reversible inhibitor of voltage-gated sodium ion channels (NaVs). Modified forms of this toxin bearing cysteine-reactive maleimide groups are available through total synthesis and are found to irreversibly inhibit sodium ion conductance in recombinantly expressed wild-type sodium channels and in hippocampal nerve cells. Our findings support a mechanism for covalent protein modification in which toxin binding to the channel pore precedes maleimide alkylation of a nucleophilic amino acid. Second-generation maleimide-toxin conjugates, which include bioorthogonal reactive groups, are also found to block channel function irreversibly; such compounds have potential as reagents for selective labeling of NaVs for live cell imaging and/or proteomics experiments.

Are benefits from diabetes self-management education sustained?

OBJECTIVES: To evaluate whether outcomes from diabetes self-management education for patients with suboptimal control were sustained. STUDY DESIGN: A randomized controlled trial of 623 adults with type 2 diabetes and glycated hemoglobin (A1C) > 7% assigned to receive conventional individual education (IE), group education (GE) using US Diabetes Conversation Maps, or usual care (UC) with no education. METHODS: A1C tests, Problem Areas in Diabetes (PAID), Diabetes Self-Efficacy (DES), Recommended Food Score (RFS), physical activity, and medication use were quantified at baseline and 1 year of follow-up through electronic health records and quarterly mailed surveys. Short-term (mean 6.8 months) and long-term (12.8 months) outcomes were evaluated using linear mixed models. In addition, follow-up trajectories were plotted in a random effects generalized additive model with smooth splines. RESULTS: Compared with UC, IE resulted in long-term improved DES and PAID scores (DES, +.11, P = .03 and PAID, -2.94, P = .04), but not significantly improved long-term RFS or physical activity change. The A1C trajectory declined more steeply in IE than GE and UC for the first 150 days post randomization. However, by 250 days, there was no treatment group A1C difference. The model fit likelihood ratio test for A1C intervention trends was significant for 3 distinct non-linear trajectories (P = .02). CONCLUSIONS: Conventional IE (but not GE) resulted in significant and sustained improvements in self-efficacy and reduced diabetes distress compared with UC, but short-term improvements in A1C, nutrition, and physical activity were not sustained. Patients may need ongoing reinforcement to achieve lasting behavioral change and glucose control.