LCoRL Regulates Growth and Metabolism.

Genome-wide association studies (GWAS) in humans and livestock have identified genes associated with metabolic traits. However, the causality of many of these genes on metabolic homeostasis is largely unclear due to a lack of detailed functional analyses. Here we report ligand-dependent corepressor-like (LCoRL) as a metabolic regulator for body weight and glucose homeostasis.

Gpr149 is involved in energy homeostasis in the male mouse.

GPR149 is an orphan receptor about which little is known. Accordingly, in the present study, we mapped the tissue expression of in mice using three complementary approaches: quantitative PCR, hybridization, and a newly generated Gpr149-Cre reporter mouse model. The strongest expressions of were observed in neurons of the islands of Calleja, the ventromedial hypothalamus, and the rostral interpeduncular nucleus.

The Integration of Proteogenomics and Ribosome Profiling Circumvents Key Limitations to Increase the Coverage and Confidence of Novel Microproteins.

There has been a dramatic increase in the identification of non-conical translation and a significant expansion of the protein-coding genome and proteome. Among the strategies used to identify novel small ORFs (smORFs), Ribosome profiling (Ribo-Seq) is the gold standard for the annotation of novel coding sequences by reporting on smORF translation. In Ribo-Seq, ribosome-protected footprints (RPFs) that map to multiple sites in the genome are computationally removed since they cannot unambiguously be assigned to a specific genomic location, or to a specific transcript in the case of multiple isoforms.

Weight loss by calorie restriction does not alter appetite-regulating gut hormone responses from perfused rat small intestine.

Aim: Postprandial secretion of the appetite-inhibiting hormones, glucagon-like peptide-1 (GLP-1), and peptide YY are reduced with obesity. It is unclear if the reduced secretion persists following weight loss (WL), if other appetite-inhibiting hormones are also reduced, and if so whether reduced secretion results from intrinsic changes in the gut.

Methods: To address whether WL may restore secretion of GLP-1 and other appetite-inhibiting hormones, we performed a gut perfusion study of the small intestine in diet-induced obese (DIO) rats after WL.

Profiling mouse brown and white adipocytes to identify metabolically relevant small ORFs and functional microproteins.

Microproteins (MPs) are a potentially rich source of uncharacterized metabolic regulators. Here, we use ribosome profiling (Ribo-seq) to curate 3,877 unannotated MP-encoding small ORFs (smORFs) in primary brown, white, and beige mouse adipocytes. Of these, we validated 85 MPs by proteomics, including 33 circulating MPs in mouse plasma.

Targeting the Gut in Obesity: Signals from the Inner Surface.

Obesity is caused by prolonged energy surplus. Current anti-obesity medications are mostly centralized around the energy input part of the energy balance equation by increasing satiety and reducing appetite. Our gastrointestinal tract is a key organ for regulation of food intake and supplies a tremendous number of circulating signals that modulate the activity of appetite-regulating areas of the brain by either direct interaction or through the vagus nerve.

Plasma GDF15 levels are similar between subjects after bariatric surgery and matched controls and are unaffected by meals.

Growth differentiating factor 15 (GDF15) is expressed in the intestine and is one of the most recently identified satiety peptides. The mechanisms controlling its secretion are unclear. The present study investigated whether plasma GDF15 concentrations are meal-related and if potential responses depend on macronutrient type or are affected by previous bariatric surgery.

Disrupting the ghrelin-growth hormone axis limits ghrelin's orexigenic but not glucoregulatory actions.

Objective: Acyl-ghrelin regulates eating, body weight, blood glucose, and GH secretion upon binding to its receptor GHSR (growth hormone secretagogue receptor; ghrelin receptor). GHSR is distributed in several brain regions and some peripheral cell-types including pituitary somatotrophs. The objective of the current study was to determine the functional significance of acyl-ghrelin's action on GHSR-expressing somatotrophs in mediating GH secretion and several of acyl-ghrelin's metabolic actions.

Characterization of a cell bridge variant connecting the nodose and superior cervical ganglia in the mouse: Prevalence, anatomical features, and practical implications.

While autonomic ganglia have been extensively studied in rats instead of mice, there is renewed interest in the anatomy of the mouse autonomic nervous system. This study examined the prevalence and anatomical features of a cell bridge linking two autonomic ganglia of the neck, namely, the nodose ganglion (NG) and the superior cervical ganglion (SCG) in a cohort of C57BL/6J mice. We identified a cell bridge between the NG and the cranial pole of the SCG.

MAGE cancer-testis antigens protect the mammalian germline under environmental stress.

Ensuring robust gamete production even in the face of environmental stress is of utmost importance for species survival, especially in mammals that have low reproductive rates. Here, we describe a family of genes called melanoma antigens (MAGEs) that evolved in eutherian mammals and are normally restricted to expression in the testis (http://MAGE.stjude.

Liver X Receptors Protect Dorsal Root Ganglia from Obesity-Induced Endoplasmic Reticulum Stress and Mechanical Allodynia.

Obesity is associated with many complications, including type 2 diabetes and painful neuropathy. There is no cure or prevention for obesity-induced pain, and the neurobiology underlying the onset of the disease is still obscure. In this study, we observe that western diet (WD)-fed mice developed early allodynia with an increase of ER stress markers in the sensory neurons of the dorsal root ganglia (DRG).

Na1.8 neurons are involved in limiting acute phase responses to dietary fat.

Objective And Methods: Metabolic viscera and their vasculature are richly innervated by peripheral sensory neurons. Here, we examined the metabolic and inflammatory profiles of mice with selective ablation of all Na1.8-expressing primary afferent neurons.

PPARγ mRNA in the adult mouse hypothalamus: distribution and regulation in response to dietary challenges.

Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that was originally identified as a regulator of peroxisome proliferation and adipocyte differentiation. Emerging evidence suggests that functional PPARγ signaling also occurs within the hypothalamus. However, the exact distribution and identities of PPARγ-expressing hypothalamic cells remains under debate.

Loss of the liver X receptor LXRα/β in peripheral sensory neurons modifies energy expenditure.

Peripheral neural sensory mechanisms play a crucial role in metabolic regulation but less is known about the mechanisms underlying vagal sensing itself. Recently, we identified an enrichment of liver X receptor alpha and beta (LXRα/β) in the nodose ganglia of the vagus nerve. In this study, we show mice lacking LXRα/β in peripheral sensory neurons have increased energy expenditure and weight loss when fed a Western diet (WD).

Glucocorticoids regulate the metabolic hormone FGF21 in a feed-forward loop.

Hormones such as fibroblast growth factor 21 (FGF21) and glucocorticoids (GCs) play crucial roles in coordinating the adaptive starvation response. Here we examine the interplay between these hormones. It was previously shown that FGF21 induces corticosterone levels in mice by acting on the brain.

MED13-dependent signaling from the heart confers leanness by enhancing metabolism in adipose tissue and liver.

The heart requires a continuous supply of energy but has little capacity for energy storage and thus relies on exogenous metabolic sources. We previously showed that cardiac MED13 modulates systemic energy homeostasis in mice. Here, we sought to define the extra-cardiac tissue(s) that respond to cardiac MED13 signaling.

FGF21 acts centrally to induce sympathetic nerve activity, energy expenditure, and weight loss.

The mechanism by which pharmacologic administration of the hormone FGF21 increases energy expenditure to cause weight loss in obese animals is unknown. Here we report that FGF21 acts centrally to exert its effects on energy expenditure and body weight in obese mice. Using tissue-specific knockout mice, we show that βKlotho, the obligate coreceptor for FGF21, is required in the nervous system for these effects.

PPARγ in vagal neurons regulates high-fat diet induced thermogenesis.

The vagus nerve innervates visceral organs providing a link between key metabolic cues and the CNS. However, it is not clear whether vagal neurons can directly respond to changing lipid levels and whether altered "lipid sensing" by the vagus nerve regulates energy balance. In this study, we systematically profiled the expression of all known nuclear receptors in laser-captured nodose ganglion (NG) neurons.

The heart-liver metabolic axis: defective communication exacerbates disease.

The heart has been recognized as an endocrine organ for over 30 years (de Bold, 2011); however, little is known about how the heart communicates with other organs in the body, and even less is known about this process in the diseased heart. In this issue of EMBO Molecular Medicine, Magida and Leinwand (2014) introduce the concept that a primary genetic defect in the heart results in aberrant hepatic lipid metabolism, which consequently exacerbates hypertrophic cardiomyopathy (HCM). This study provides evidence in support of the hypothesis that crosstalk occurs between the heart and liver, and that this becomes disrupted in the diseased state.

FGF21 regulates metabolism and circadian behavior by acting on the nervous system.

Fibroblast growth factor 21 (FGF21) is a hepatokine that acts as a global starvation signal to modulate fuel partitioning and metabolism and repress growth; however, the site of action of these diverse effects remains unclear. FGF21 signals through a heteromeric cell-surface receptor composed of one of three FGF receptors (FGFR1c, FGFR2c or FGFR3c) in complex with β-Klotho, a single-pass transmembrane protein that is enriched in metabolic tissues. Here we show that in addition to its known effects on peripheral metabolism, FGF21 increases systemic glucocorticoid levels, suppresses physical activity and alters circadian behavior, which are all features of the adaptive starvation response.

FGF21 contributes to neuroendocrine control of female reproduction.

Preventing reproduction during nutritional deprivation is an adaptive process that is conserved and essential for the survival of species. In mammals, the mechanisms that inhibit fertility during starvation are complex and incompletely understood. Here we show that exposure of female mice to fibroblast growth factor 21 (FGF21), a fasting-induced hepatokine, mimics infertility secondary to starvation.

Nuclear receptor LRH-1 induces the reproductive neuropeptide kisspeptin in the hypothalamus.

The differential expression and secretion of the neuropeptide kisspeptin from neurons in the arcuate (Arc) and anteroventral periventricular (AVPV) nuclei of the hypothalamus coordinate the temporal release of pituitary gonadotropins that control the female reproductive cycle. However, the molecular basis for this differential regulation is incompletely understood. Here, we report that liver receptor homolog-1 (LRH-1), a member of the nuclear receptor superfamily, is expressed in kisspeptin neurons in the Arc but not in the AVPV in female mice.

NR4A nuclear receptors support memory enhancement by histone deacetylase inhibitors.

The formation of a long-lasting memory requires a transcription-dependent consolidation period that converts a short-term memory into a long-term memory. Nuclear receptors compose a class of transcription factors that regulate diverse biological processes, and several nuclear receptors have been implicated in memory formation. Here, we examined the potential contribution of nuclear receptors to memory consolidation by measuring the expression of all 49 murine nuclear receptors after learning.

The G protein-coupled taste receptor T1R1/T1R3 regulates mTORC1 and autophagy.

Cells continually assess their energy and nutrient state to maintain growth and survival and engage necessary homeostatic mechanisms. Cell-autonomous responses to the fed state require the surveillance of the availability of amino acids and other nutrients. The mammalian target of rapamycin complex 1 (mTORC1) integrates information on nutrient and amino acid availability to support protein synthesis and cell growth.

βKlotho is required for fibroblast growth factor 21 effects on growth and metabolism.

Fibroblast growth factor 21 (FGF21) is a fasting-induced hepatokine that has potent pharmacologic effects in mice, which include improving insulin sensitivity and blunting growth. The single-transmembrane protein βKlotho functions as a coreceptor for FGF21 in vitro. To determine if βKlotho is required for FGF21 action in vivo, we generated whole-body and adipose tissue-selective βKlotho-knockout mice.