Pro-melanin-concentrating Hormone Research Articles

Exploring and bioinformatics analysis of differentially expressed genes in bronchial asthma

Objective: To screen core differentially expressed genes of bronchial asthma and conduct bioinformatics analysis. Methods: Macrophage microarray data GSE22528 from asthma patients were downloaded from gene expression database (GEO). The dataset included transcriptome information from 10 human alveolar lavage fluid samples, and five of them were from allergic asthmatic subjects and five from control subjects. Differential expression genes (DEGs) were screened by R 4.0.4 software. Gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to select DEGs using DAVID 6.8 database. Protein interaction network (PPI) was constructed from DEGs encoded proteins using STRING online database. Cytoscape software was used to construct core modules and determine core DEGs. Results: Alveolar lavage fluid samples were all collected from Caucasian Canadians, with age range as (20, 37) and (18, 36) years, respectively, including 3 males for each group. In asthmatic patients, 449 genes were up-regulated and 47 down-regulated. GO analysis showed that the up-regulated genes in asthmatic patients were mainly involved in biological processes such as response to folded proteins, and the molecular function was focused on binding of folded proteins and growth factors. Down-regulated genes were mainly involved in biological processes such as histone deacetylation and ubiquitin-mediated protein degradation, and their molecular functions focused on histone deacetylation activity. KEGG pathway enrichment analysis showed that pathways were mainly enriched by up-regulation genes, involving Hippo signaling pathway, hypertrophic cardiomyopathy, estrogen signaling pathway, arrhythmogenic right ventricular cardiomyopathy, basal cell carcinoma, neuro-activated receptor ligand interaction, dilated cardiomyopathy and adhesion and connection signaling pathways. Two core modules were obtained by PPI analysis, and 14 core DEGs were screened out. They were pro-melanin concentrating hormone (PMCH), prepronociceptin (PNOC), Sphingosinol-1-phosphate receptor 2 (S1PR2), Sphingosinol-1-phosphate receptor 5 (S1PR5), CC-type chemokine ligand 21 (CCL21), Kelch-like protein 25 (KLHL25), ubiquitin binding enzyme E2V2 (UBE2V2), F-box protein 17 (FBXO17), taste receptor type 2 member 3 (TAS2R3), somatostatin receptor 2 (SSTR2), metabolic glutamate receptor 2 (GRM2), Lister E3 ubiquitin protein ligase 1 (LTN1), LIM domain specific protein 7 (LMO7) and ring finger protein 19A gene(RNF19A), in which LTN1 and UBE2V2 were down-regulated and the rest were up-regulated. Conclusion: DEGs was found in macrophages of asthmatic and control individuals. PMCH, PNOC, S1PR2, S1PR5 and CCL21 might be the core genes in the pathological process of asthma.

Depletion of Alpha-Melanocyte-Stimulating Hormone Induces Insatiable Appetite and Gains in Energy Reserves and Body Weight in Zebrafish.

The functions of anorexigenic neurons secreting proopiomelanocortin (POMC)/alpha-melanocyte-stimulating hormone (α-MSH) of the melanocortin system in the hypothalamus in vertebrates are energy homeostasis, food intake, and body weight regulation. However, the mechanisms remain elusive. This article reports on zebrafish that have been genetically engineered to produce α-MSH mutants, α-MSH−7aa and α-MSH−8aa, selectively lacking 7 and 8 amino acids within the α-MSH region, but retaining most of the other normal melanocortin-signaling (Pomc-derived) peptides. The α-MSH mutants exhibited hyperphagic phenotypes leading to body weight gain, as observed in human patients and mammalian models. The actions of several genes regulating appetite in zebrafish are similar to those in mammals when analyzed using gene expression analysis. These include four selected orexigenic genes: Promelanin-concentrating hormone (pmch), agouti-related protein 2 (agrp2), neuropeptide Y (npy), and hypothalamic hypocretin/orexin (hcrt). We also study five selected anorexigenic genes: Brain-derived neurotrophic factor (bdnf), single-minded homolog 1-a (sim1a), corticotropin-releasing hormone b (crhb), thyrotropin-releasing hormone (trh), and prohormone convertase 2 (pcsk2). The orexigenic actions of α-MSH mutants are rescued completely after hindbrain ventricle injection with a synthetic analog of α-MSH and a melanocortin receptor agonist, Melanotan II. We evaluate the adverse effects of MSH depletion on energy balance using the Alamar Blue metabolic rate assay. Our results show that α-MSH is a key regulator of POMC signaling in appetite regulation and energy expenditure, suggesting that it might be a potential therapeutic target for treating human obesity.

A SNP within the PMCH gene as a molecular marker associated with fertility traits in Angus and Brangus beef heifers raised under a desert environment.

Components of the GH/IGF1 endocrine axis regulate growth and reproductive traits in cattle. The pro-melanin-concentrating hormone (PMCH) gene located within chromosome 5 belongs to this axis. Objective herein was to evaluate PMCH single-nucleotide polymorphisms (SNPs) as molecular markers associated with age at first calving, calving interval, and age at second calving in Angus and Brangus beef heifers raised in desert conditions. Five SNPs within the PMCH gene were included in the study. Three of these SNPs had minor allele frequency > 10% and only one SNP did not deviate from Hardy-Weinberg equilibrium. A genotype to phenotype association analyses was performed using a mixed-effects model which included phenotype as the response variable, SNP genotype, breed, year of birth and age of dam as fixed terms, and sire as a random effect. Genotypes from the SNP rs135033882 were found to be associated (P < 0.05) with all evaluated fertility traits, and the term breed resulted as a significant source of variation only for age at second calving. The allele A was the favorable allele because it decreased the age at first calving 98.6days, the calving interval 85.3days, and the age at second calving 183.1days, in Angus and Brangus heifers. In conclusion, we proposed a SNP within the PMCH gene as a potential candidate marker associated with reproductive performance in Angus and Brangus beef heifers raised in a desert climate.

Proteomic Analysis of Tear Film Obtained from Diabetic Dogs.

Simple SummaryCanine diabetes is a serious disease, which can lead to severe complications, eventually even death. Currently, all the diagnostic procedures are the invasive ones, with blood collection remaining as a golden standard for both initial diagnosis, and later follow-up. Tears can be obtained in a non-invasive manner, which makes them a perfect candidate for a screening tool in canine diabetes. In this study we aimed to analyze the protein composition of the tears collected from the healthy animals and compared it to the diabetic group. There are significant differences between these two groups, and we believe that the identified proteins hold promise as a potential diagnostic tool, which can be later on used both in clinical practice, and for better understanding of the disease.Canine diabetes mellitus is a significant health burden, followed with numerous systemic complications, including diabetic cataracts and retinopathy, leading to blindness. Diabetes should be considered as a disease damaging all the body organs, including gastrointestinal tract, through a complex combination of vascular and metabolic pathologies, leading to impaired gut function. Tear film can be obtained in a non-invasive way, which makes it a feasible biomarker source. In this study we compared proteomic changes ongoing in tear film of diabetic dogs. The study group consisted of 15 diabetic dogs, and 13 dogs served as a control group. After obtaining tear film with Schirmer strips, we performed 2-dimensional electrophoresis, followed by Delta2D software analysis, which allowed to select statistically significant differentially expressed proteins. After their identification with MALDI-TOF (matrix assisted laser desorption and ionisation time of flight) spectrometry we found one up-regulated protein in tear film of diabetic dogs—SRC kinase signaling inhibitor 1 (SRCIN1). Eight proteins were down-regulated: phosphatidylinositol-4 kinase type 2 alpha (PI4KIIα), Pro-melanin concentrating hormone (Pro-MCH), Flotillin-1, Protein mono-ADP ribosyltransferase, GRIP and coiled coil domain containing protein 2, tetratricopeptide repeat protein 36, serpin, and Prelamin A/C. Identified proteins were analyzed by Panther Gene Ontology software, and their possible connections with diabetic etiopathology were discussed. We believe that this is the first study to target tear film proteome in canine diabetes. We believe that combined with traditional examination, the tear film proteomic analysis can be a new source of biomarkers both for clinical practice, and experimental research.

Identification of candidate genes and regulatory factors related to growth rate through hypothalamus transcriptome analyses in broiler chickens

BackgroundIntensive selection for growth rate (GR) in broiler chickens carries negative after-effects, such as aberrations in skeletal development and the immune system, heart failure, and deterioration of meat quality. In Poland, fast-growing chicken populations are highly non-uniform in term of growth rate, which is highly unprofitable for poultry producers. Therefore, the identification of genetic markers for boiler GR that could support the selection process is needed. The hypothalamus is strongly associated with growth regulation by inducing important pituitary hormones. Therefore, the present study used this tissue to pinpoint genes involved in chicken growth control.ResultsThe experiment included male broilers of Ross 308 strain in two developmental stages, after 3rd and 6th week of age, which were maintained in the same housing and feeding conditions. The obtained results show for the overexpression of genes related to orexigenic molecules, such as neuropeptide Y (NPY), aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), galanin (GAL), and pro-melanin concentrating hormone (PMCH) in low GR cockerels.ConclusionThe results reveal strong associations between satiety centre and the growth process. The present study delivers new insights into hypothalamic regulation in broiler chickens and narrows the area for the searching of genetic markers for GR.Graphical abstract

Melanin Concentrating Hormone Signaling Deficits in Schizophrenia: Association with Memory and Social Impairments and Abnormal Sensorimotor Gating

BackgroundEvidence from anatomical, pharmacological, and genetic studies supports a role for the neuropeptide melanin concentrating hormone system in modulating emotional and cognitive functions. Genome-wide association studies revealed a potential association between the melanin concentrating hormone receptor (MCHR1) gene locus and schizophrenia, and the largest genome-wide association study conducted to date shows a credible genome-wide association.MethodsWe analyzed MCHR1 and pro-melanin concentrating hormone RNA-Seq expression in the prefrontal cortex in schizophrenia patients and healthy controls. Disruptions in the melanin concentrating hormone system were modeled in the mouse brain by germline deletion of MCHR1 and by conditional ablation of melanin concentrating hormone expressing neurons using a Cre-inducible diphtheria toxin system.ResultsMCHR1 expression is decreased in the prefrontal cortex of schizophrenia samples (false discovery rate (FDR) P < .05, CommonMind and PsychEncode combined datasets, n = 901) while pro-melanin concentrating hormone is below the detection threshold. MCHR1 expression decreased with aging (P = 6.6E-57) in human dorsolateral prefrontal cortex. The deletion of MCHR1 was found to lead to behavioral abnormalities mimicking schizophrenia-like phenotypes: hyperactivity, increased stereotypic and repetitive behavior, social impairment, impaired sensorimotor gating, and disrupted cognitive functions. Conditional ablation of pro-melanin concentrating hormone neurons increased repetitive behavior and produced a deficit in sensorimotor gating.ConclusionsOur study indicates that early disruption of the melanin concentrating hormone system interferes with neurodevelopmental processes, which may contribute to the pathogenesis of schizophrenia. Further neurobiological research on the developmental timing and circuits that are affected by melanin concentrating hormone may lead to a therapeutic target for early prevention of schizophrenia.

Neurotensin Enhances Locomotor Activity and Arousal and Inhibits Melanin-Concentrating Hormone Signaling

Background: Hypothalamic neurotensin (Nts)-secreting neurons regulate fundamental physiological processes including metabolism and feeding. However, the role of Nts in modulation of locomotor activity, sleep, and arousal is unclear. We previously identified and characterized Nts neurons in the zebrafish hypothalamus. Materials and Methods: In order to study the role of Nts, nts mutant (nts–/–), and overexpressing zebrafish were generated. Results: The expression of both nts mRNA and Nts protein was reduced during the night in wild-type zebrafish. Behavioral assays revealed that locomotor activity was decreased during both day and night, while sleep was increased exclusively during the nighttime in nts–/– larvae. Likewise, inducible overexpression of Nts increased arousal in hsp70:Gal4/uas:Nts larvae. Furthermore, the behavioral response to light-to-dark transitions was reduced in nts–/– larvae. In order to elucidate potential contenders that may mediate Nts action on these behaviors, we profiled the transcriptome of 6 dpf nts–/– larvae. Among other genes, the expression levels of melanin-concentrating hormone receptor 1b were increased in nts–/– larvae. Furthermore, a portion of promelanin-concentrating hormone 1 (pmch1) and pmch2 neurons expressed the nts receptor. In addition, expression of the the two zebrafish melanin-concentrating hormone (Mch) orthologs, Mch1 and Mch2, was increased in nts–/– larvae. Conclusion: These results show that the Nts and Mch systems interact and modulate locomotor activity and arousal.

Frequencies of candidate genes and associations with carcass and meat traits in Nellore and crossbred cattle

Abstract: The objective of this work was to estimate allelic frequencies of the polymorphisms IGF2/MboII (G &gt; T) of the insulin-like growth factor 2 (IGF2) gene, DQ499531.1:g.134A &gt; T of the pro-melanin-concentrating hormone (PMCH) gene, and DQ667048.1:g.3290G &gt; T of the RARrelated orphan receptor C (RORC) gene in beef cattle of different genetic groups, and to evaluate the associations between these polymorphisms and traits related to carcass composition and meat quality. Data on carcass and meat quality of 499 animals was used: of 313 Nellore (Bos indicus) and of 186 Nellore crossed with different taurine (Bos taurus) breeds. For the IGF2/MboII polymorphism, the frequencies found for the G allele were 0.231 and 0.631 for Nellore and crossed breeds, respectively. For the DQ499531.1:g.134A &gt; T polymorphism, the allelic frequencies of A were 0.850 for Nellore and 0.905 for crossed breeds. For the DQ667048.1:g.3290G &gt; T polymorphism, the allelic frequencies of G were 0.797 and 0.460 for Nellore and crossed breeds, respectively. The evaluated single nucleotide polymorphisms (SNPs) are not significantly associated with carcass and meat traits (rib eye area, back fat thickness, shear force, total lipids, and myofibrillar fragmentation index), suggesting little utility of the analyzed polymorphisms of the IGF2, PMHC, and RORC genes as selection markers in the studied cattle populations.

Association of pro-melanin concentrating hormone genotype with beef carcass quality and yield1

Beef cattle from 3 independent studies conducted in the Texas Panhandle (Exp. 1: n = 3,906 and Exp. 2: n = 4,000) and southern Idaho (Exp. 3; n = 542) were used to investigate the association of pro-melanin concentrating hormone (PMCH) genotype with beef carcass quality and yield attributes. Tissue samples were collected from each animal to determine which PMCH allele they expressed (Trial 1: AA, 62.60%; AT, 32.05%; and TT, 5.35%; Trial 2: AA, 64.33%; AT, 31.07%; and TT, 4.60%; Trial 3: AA, 65.87%; AT, 29.34%; and TT, 4.80%). Twenty-four hours after harvest, carcass attributes were evaluated for all carcasses and longissimus dorsi steak samples were allocated from a subset of carcasses in Exp. 2 (n = 352; AA, 49.43%; AT, 28.98%; and TT, 21.59%) and each carcass in Exp. 3. Warner-Bratzler shear force measurements were determined for each steak after aging for 7, 14, or 21 d postmortem. Carcasses from Exp. 1 and 2 expressing the AA genotype had greater (P < 0.01) 12th rib subcutaneous (s.c.) fat depth and marbling scores, concurrent with smaller (P < 0.01) LM area than carcasses of AT and TT genotypes. Subsequently, carcasses expressing the AA genotype were represented by a greater (P < 0.02) proportion achieving Prime and Premium Choice quality grades, and a lesser (P < 0.01) proportion grading Select or Standard. In all trials, carcasses of the AA genotype had greater (P < 0.04) calculated yield grades than carcasses of the TT genotype. Carcass composition was associated with PMCH genotype evident by calculated empty body fat differences (P < 0.04) between AA and TT cattle in Exp. 1 and 3, and differences (P < 0.01) among all 3 genotypes in Trial 2. Shear force data on 7-d postmortem aging tended (P = 0.06) to favor cattle of the AA genotype in Exp. 2. However, additional aging to 14 or 21 d minimized any tenderness differences. These data illustrate the potential relationship that may exist among PMCH genotypes and indicators of carcass composition.

Impact of Tumor Infiltrating T Cells in Patients with Diffuse Large B-Cell Lymphoma

AbstractAbstract 1572Previous studies have demonstrated the importance of the non-malignant tumor-infiltrating immune cells in the tumor microenvironment at diagnosis in patients with non-Hodgkin's lymphoma (NHL). We aimed to investigate the molecular mechanisms whereby tumor infiltrating T cells (TILs) are altered in follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL). We used gene expression profiling of highly purified CD4 and CD8 infiltrating T-cells (TILs) from FL patients and reported that PMCH, ETV1 and NAMPT are highly expressed in both CD4 and CD8 TILs and showed in tissue microarrays (TMA) that expression of pro-melanin-concentrating hormone (PMCH), ets variant 1 (ETV1) and nicotinamide phosphoribosyltransferase (NAMPT) in T-cells have prognostic impact in disease specific survivals (DSS) and time to transformation (TT) in patients with FL. In addition, PMCH and NAMPT were shown to be independently significant in TT in multivariate analysis.We next examined expression of these gene products in T cells in FL samples before and after transformation to DLBCL (n=29). Comparing total number of positive cells for expression of proteins of interest, we demonstrate there is a significant decline in PMCH (p=0.035), EVT1 (p=0.018) and NAMPT (p=0.0136) expressing cells after transformation. We further investigated the prognostic impact of expression of these proteins in T cells in patients with DLBCL in two treatment groups, those receiving rituximab (n=68) and in a historic non-rituximab (n=130) treated cohort. By assessing the number of positive cells and the impact on survival using Kaplan-Meier analysis, we now show that the T-cell expressed genes PMCH, ETV1 and NAMPT have prognostic significance for overall survival (OS) in patients with DLBCL. Patients with higher number of PMCH expressing T-cells showed significant longer survivals in both rituximab (p=0.027) and non-rituximab (p=0.033) treated groups. In contrast to PMCH, and in line with our previous data in FL, patients with higher number of NAMPT expressing cells showed significantly shorter OS in the rituximab (p=0.046) treated group, with a trend towards shorter OS in non-rituximab (p=0.064) treated group. Patients with higher percentage of ETV1 expressing cells had longer OS in the non-Rituximab group (p=0.008), with only a trend towards OS with rituximab treatment (p=0.067). We are examining this further in a larger cohort of rituximab treated patients.Our previous data has indicated that TILs in patients with FL are abnormal in terms of their gene expression and function. We now show that changes in protein expression in TILs have an impact on transformation in patients with FL and on survival in both FL and DLBCL. We are further characterizing the mechanisms of gene expression alteration in TILs of patients with FL and DLBCL and its functional consequences in the biology and of the disease. It appears that altered gene expression in TILs plays a fundamental role in transformation and may be important in the survivals and biology of NHL. Since non-malignant infiltrating immune cells have a crucial role in the outcome of patients with FL and DLBCL, understanding the nature and impact of the abnormalities induced in TILs in these patients is crucial before any immunotherapeutic strategies can be implemented to attempt to alter the immune microenvironment in NHL. Disclosures:Gribben:Celgene: Honoraria.

Primate-specific spliced PMCHL RNAs are non-protein coding in human and macaque tissues

BackgroundBrain-expressed genes that were created in primate lineage represent obvious candidates to investigate molecular mechanisms that contributed to neural reorganization and emergence of new behavioural functions in Homo sapiens. PMCHL1 arose from retroposition of a pro-melanin-concentrating hormone (PMCH) antisense mRNA on the ancestral human chromosome 5p14 when platyrrhines and catarrhines diverged. Mutations before divergence of hylobatidae led to creation of new exons and finally PMCHL1 duplicated in an ancestor of hominids to generate PMCHL2 at the human chromosome 5q13. A complex pattern of spliced and unspliced PMCHL RNAs were found in human brain and testis.ResultsSeveral novel spliced PMCHL transcripts have been characterized in human testis and fetal brain, identifying an additional exon and novel splice sites. Sequencing of PMCHL genes in several non-human primates allowed to carry out phylogenetic analyses revealing that the initial retroposition event took place within an intron of the brain cadherin (CDH12) gene, soon after platyrrhine/catarrhine divergence, i.e. 30–35 Mya, and was concomitant with the insertion of an AluSg element. Sequence analysis of the spliced PMCHL transcripts identified only short ORFs of less than 300 bp, with low (VMCH-p8 and protein variants) or no evolutionary conservation. Western blot analyses of human and macaque tissues expressing PMCHL RNA failed to reveal any protein corresponding to VMCH-p8 and protein variants encoded by spliced transcripts.ConclusionOur present results improve our knowledge of the gene structure and the evolutionary history of the primate-specific chimeric PMCHL genes. These genes produce multiple spliced transcripts, bearing short, non-conserved and apparently non-translated ORFs that may function as mRNA-like non-coding RNAs.

Genetic variation in the pro‐melanin‐concentrating hormone gene affects carcass traits in Bos taurus cattle

Mammalian pro-melanin-concentrating hormone (PMCH) has previously been shown to affect feed intake in rodent species. The objectives of this study were to sequence the Bos taurus PMCH gene in order to identify any existing genetic variants and to evaluate whether these affected carcass traits. An A-to-T SNP was identified at position -134 relative to the ATG start codon (g.-134A>T). The alleles at this SNP were significantly associated with average fat and grade fat in two crossbred populations of Bos taurus cattle. The g.-134T allele may introduce a binding site for the transcriptional repressor, adenovirus E4 promoter binding protein, which may contribute to this effect. The g.-134A allele occurred in 67% of cattle examined and was associated with higher fat levels.

Human Th2 cells selectively express the orexigenic peptide, pro-melanin-concentrating hormone

Th1 and Th2 cells represent the two main functional subsets of CD4(+) T helper cell, and are defined by their cytokine expression. Human Th1 cells express IFNgamma, whilst Th2 cells express IL-4, IL-5, and IL-13. Th1 and Th2 cells have distinct immunological functions, and can drive different immunopathologies. Here, we show that in vitro-differentiated human Th2 cells highly selectively express the gene for pro-melanin-concentrating hormone (PMCH), using real-time RT-PCR, enzyme immunoassay, and Western blot analysis. PMCH encodes the prohormone, promelanin-concentrating hormone (PMCH), which is proteolytically processed to produce several peptides, including the orexigenic hormone melanin-concentrating hormone (MCH). PMCH expression by Th2 cells was activation responsive and increased throughout the 28-day differentiation in parallel with the expression of the Th2 cytokine genes. MCH immunoreactivity was detected in the differentiated Th2 but not Th1 cell culture supernatants after activation, and contained the entire PMCH protein, in addition to several smaller peptides. Human Th1 and Th2 cells were isolated by their expression of IFNgamma and CRTH2, respectively, and the ex vivo Th2 cells expressed PMCH upon activation, in contrast to the Th1 cells. Because Th2 cells are central to the pathogenesis of allergic diseases including asthma, expression of PMCH by activated Th2 cells in vivo may directly link allergic inflammation to energy homeostasis and may contribute to the association between asthma and obesity.

Possible association of the pro‐melanin‐concentrating hormone gene with a greater body mass index as a side effect of the antipsychotic olanzapine

Following our report of a linkage at 12q24 with a phenotype of obesity under antipsychotics, we tested the pro-melanin-concentrating hormone (PMCH) candidate gene for a possible association in humans with the body mass index (BMI; kg/m2) in unrelated schizophrenic patients (SZ) receiving antipsychotics (N = 300) and in controls (CTL; N = 150). Subjects were classified in obese (OB) (BMI > or = 30 kg/m2), overweight (25 < or = BMI < 30 kg/m2), and normal weight (BMI < 25 kg/m2) groups. Single nucleotide polymorphisms (SNP) rs7973796 and rs11111201, located 5' at -4.5 kb and 3' at +1.8 kb, respectively, of PMCH were genotyped. Interaction effects of genotypes and antipsychotic treatment on BMI were tested in a covariance analysis with age and gender as covariates. Interaction effects on the prevalence of obesity were tested in a logistic regression analysis. For subjects under 50 years, the effect of the rs7973796 genotype on BMI differed between the SZ patients taking olanzapine and CTL group (interaction P = 0.025). Olanzapine-treated SZ patients carrying the ancestral homozygote genotype showed a higher BMI for rs7973796 (P = 0.016 with the LSMeans t-test) than the variant homozygotes. Accordingly, the ORs for obesity associated with rs7973796 genotypes differed in the SZ patients taking olanzapine compared to the CTL group (interaction P = 0.0094). The G allele was associated with an increase in the odds of obesity in SZ patients taking olanzapine. No association was observed for those over 50 years, or for rs11111201. These results suggest that the common allele of PMCH rs7973796 may be associated with a greater BMI in olanzapine-treated SZ patients.

The role of prohormone convertase‐2 in hypothalamic neuropeptide processing: a quantitative neuropeptidomic study

Prohormone convertase (PC) 1/3 and 2 are involved in the generation of neuropeptides from their precursors. A quantitative peptidomic approach was used to explore the role PC2 plays in the processing of hypothalamic peptides. In this approach, extracts from mice lacking PC2 activity and from wild-type littermates were labeled with isotopic tags, combined, fractionated on a reverse phase HPLC column, and analyzed by electrospray ionization mass spectrometry. Altogether, 53 neuropeptides or other peptides derived from secretory pathway proteins were identified and sequenced using tandem mass spectrometry. These peptides arise from 21 distinct proteins: proenkephalin, proopiomelanocortin, prodynorphin, protachykinin A and B, procholecystokinin, promelanin-concentrating hormone, proneurotensin, proneuropeptide Y, provasopressin, pronociceptin/orphanin, prothyrotropin-releasing hormone, cocaine- and amphetamine-regulated transcript, chromogranin A and B, secretogranin II, prohormone convertase 1 and 2, propeptidyl-amidating monooxygenase, and proteins designated proSAAS and VGF. Approximately one third of the peptides found in wild-type mice were not detectable in PC2 knock-out mice, and another third were present at levels ranging from 25 to 75% of wild-type levels. Comparison of the cleavage sites suggests that sequences with a Trp, Tyr and/or Pro in the P1' or P2' position, or a basic residue in the P3 position, are preferentially cleaved by PC2 and not by other enzymes present in the secretory pathway.

A genome wide linkage study of obesity as secondary effect of antipsychotics in multigenerational families of eastern Quebec affected by psychoses.

Antipsychotics can induce in schizophrenic (SZ) and bipolar disorder (BP) patients serious body weight changes that increase risk for noncompliance to medication, and risk for cardiovascular diseases and diabetes. A genetic origin for this susceptibility to weight changes has been hypothesized because only a proportion of treated patients are affected, the degree of affection differing also in rates and magnitudes. In a first genome scan on obesity under antipsychotics in SZ and BP, we analyzed 21 multigenerational kindreds (508 family members) including several patients treated for a minimum of 3 years mainly with haloperidol or chlopromazine. Obesity was defined from medical files and was shown to be 2.5 times more frequent in patients treated with antipsychotics than in untreated family members (30 vs 12%). The nine pedigrees that showed at least two occurrences of obesity under antipsychotics were submitted to model-based linkage analyses. We observed a suggestive linkage with a multipoint Lod score (MLS) of 2.74 at 12q24. This linkage finding vanished when we used as phenotypes, obesity unrelated to antipsychotics, and when we used SZ or BP. This suggests that this positive linkage result with obesity is specific to the use of antipsychotics. A potential candidate gene for this linkage is the pro-melanin-concentrating hormone (PMCH) gene located at less then 1 cM of the linkage. PMCH encodes a neuropeptide involved in the control of food intake, energy expenditure, and in anxiety/depression. This first genome scan targeting the obesity side effect of antipsychotics identified 12q24 as a susceptibility region.

Radiation hybrid mapping of the two highly homologous human-variant pMCHL genes by PCR-SSCP.

When gene loci are very similar in sequence, as in gene families or multiple pseudogenes, it is difficult to determine the specific location of the individual genes. We show here that applying PCR-SSCP to a radiation hybrid panel allowed mapping and specific sequencing of two genes with only a few sequence differences. Human-variant forms of the promelanin-concentrating hormone (pMCH) gene are found in two locations in the genome, previously localized by FISH to 5p14 and 5q12-q13. Without prior knowledge of sequence variation between the loci, we observed a difference in migration pattern in PCR-SSCP, indicating the presence of at least one point of sequence divergence. PCR-SSCP of 93 samples from a human-hamster radiation hybrid panel revealed the location of the genes to be between markers WI-4804 and AFM225YC5 on chromosome 5p, and between markers WI-3133 and WI-4225 on chromosome 5q. Sequencing of the two 680-bp PCR products from the hybrid panel demonstrated 3 bases of sequence difference between the 5p and 5q locations.

Pro-melanin-concentrating hormone gene ( PMCH) is localized on human chromosome 12q and rat chromosome 7

Melanin-concentrating hormone (MCH) is a cyclic neuropeptide that may be involved in regulation of the stress response and food intake behavior in mammals. MCH and two other putative neuropeptides, NEI and NGE, are encoded by the same precursor, designated pro-melanin-concentrating hormone ( PMCH). A panel of somatic cell hybrids segregating either human or rat chromosomes was used to determine the chromosomal localization of the PMCH locus. It was assigned to human chromosome 12q and to rat chromosome 7. This is the first neuropeptide-encoding gene found in this new synteny group conserved in rat and human.