Transcriptomic (DNA Microarray) and Metabolome (LC-TOF-MS) Analyses of the Liver in High-Fat Diet Mice after Intranasal Administration of GALP (Galanin-like Peptide).

The aim of this research was to test the efficacy and potential clinical application of intranasal administration of galanin-like peptide (GALP) as an anti-obesity treatment under the hypothesis that GALP prevents obesity in mice fed a high-fat diet (HFD). Focusing on the mechanism of regulation of lipid metabolism in peripheral tissues via the autonomic nervous system, we confirmed that, compared with a control (saline), intranasally administered GALP prevented further body weight gain in diet-induced obesity (DIO) mice with continued access to an HFD. Using an omics-based approach, we identified several genes and metabolites in the liver tissue of DIO mice that were altered by the administration of intranasal GALP. We used whole-genome DNA microarray and metabolomics analyses to determine the anti-obesity effects of intranasal GALP in DIO mice fed an HFD. Transcriptomic profiling revealed the upregulation of flavin-containing dimethylaniline monooxygenase 3 (Fmo3), metallothionein 1 and 2 (Mt1 and Mt2, respectively), and the Aldh1a3, Defa3, and Defa20 genes. Analysis using the DAVID tool showed that intranasal GALP enhanced gene expression related to fatty acid elongation and unsaturated fatty acid synthesis and downregulated gene expression related to lipid and cholesterol synthesis, fat absorption, bile uptake, and excretion. Metabolite analysis revealed increased levels of coenzyme Q10 and oleoylethanolamide in the liver tissue, increased levels of deoxycholic acid (DCA) and taurocholic acid (TCA) in the bile acids, increased levels of taurochenodeoxycholic acid (TCDCA), and decreased levels of ursodeoxycholic acid (UDCA). In conclusion, intranasal GALP administration alleviated weight gain in obese mice fed an HFD via mechanisms involving antioxidant, anti-inflammatory, and fatty acid metabolism effects and genetic alterations. The gene expression data are publicly available at NCBI GSE243376.

Plasma and aqueous levels of alarin and adipsin in patients with and without diabetic retinopathy.

BACKROUND: Diabetic retinopathy is a disease seen with microvascular complications as a result of hyperglycemia and insulin resistance. Alarin and Adipsin are molecules with a role in energy and glucose metabolism. The aim of this study was to determine plasma and aqueous levels of Alarin and Adipsin in patients with and without diabetic retinopathy to evaluate their potential roles in diabetic retinopathy. METHODS: The study included one eye from each of 20 cataract patients without diabetes (C), 20 cataract patients with diabetes and without diabetic retinopathy (DM + C), and 20 cataract patients with diabetes and diabetic retinopathy (DR + C). Plasma and aqueous humour samples were taken from all patients during the cataract operation. Alarin and Adipsin levels were examined with the enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Both plasma and aqueous Alarin levels were significantly higher in the patients with diabetic retinopathy than in the control group (p < 0.001, p = 0.006). Adipsin levels were found to be significantly higher in plasma in the control group than in the DR + C group and significantly higher in aqueous in the DR + C group than in the control group (p < 0.001, p < 0.001). CONCLUSION: These findings suggest that Alarin and Adipsin may play important role in diabetic retinopathy.

Alarin: A new predictive marker in infertile women with polycystic ovary syndrome: A case-control study.

AIM: There is scant evidence concerning the relationship of alarin concentrations for polycystic ovary syndrome (PCOS) status in the existing literature. Therefore, we aimed to reveal the relationship about predictive value of serum alarin concentrations for PCOS risk in infertile women. METHODS: This prospective case-control study included a total of 151 infertile women who met eligibility criteria of the study. Infertile women diagnosed with PCOS formed the study group (n = 80). Women with diagnoses of unexplained infertility constituted the control group (n = 71). The biochemical analyses of serum concentrations of lipid profiles, estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-Mullerian hormone (AMH) and alarin were performed. RESULTS: There were no differences for the study parameters, including age, body mass index, fasting glucose, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total triglyceride, E2, and FSH levels in either group. Serum LH, AMH, alarin concentrations, and antral follicle counts had higher values in the PCOS group compared with the controls. Correlation analysis revealed that serum alarin levels were significantly positively correlated with LH and AMH levels, only in the PCOS group. Multivariate binary logistic regression analysis demonstrated that infertile women with high alarin concentrations were significantly more likely to develop PCOS (OR = 1.77, 95% CI = 0.095-0.332, p < 0.001). CONCLUSION: Higher serum concentrations of alarin and a positive correlation with serum LH levels were found in infertile women with PCOS. This evidence supported that high alarin concentrations might play a role in the development of PCOS.

Galanin peptide family regulation of glucose metabolism.

Recent preclinical and clinical studies have indicated that the galanin peptide family may regulate glucose metabolism and alleviate insulin resistance, which diminishes the probability of type 2 diabetes mellitus. The galanin was discovered in 1983 as a gut-derived peptide hormone. Subsequently, galanin peptide family was found to exert a series of metabolic effects, including the regulation of gut motility, body weight and glucose metabolism. The galanin peptide family in modulating glucose metabolism received recently increasing recognition because pharmacological activiation of galanin signaling might be of therapeutic value to improve insuin resistance and type 2 diabetes mellitus. To date, however, few papers have summarized the role of the galanin peptide family in modulating glucose metabolism and insulin resistance. In this review we summarize the metabolic effect of galanin peptide family and highlight its glucoregulatory action and discuss the pharmacological value of galanin pathway activiation for the treatment of glucose intolerance and type 2 diabetes mellitus.

Alarin alleviated cardiac fibrosis via attenuating oxidative stress in heart failure rats.

The present study was to explore whether alarin could alleviate heart failure (HF) and attenuate cardia fibrosis via inhibiting oxidative stress. The fibrosis of cardiac fibroblasts (CFs) was induced by angiotensin (Ang) II. HF models were induced by ligation of the left anterior descending artery to cause ischemia myocardial infarction (MI) in Sprague-Dawley rats. Alarin (1.0 nM/kg/d) was administrated by intraperitoneal injection for 28 days. The decreases of left ventricular (LV) ejection fraction (EF), fractional shortening (FS), the maximum of the first differentiation of LV pressure (LV ± dp/dtmax) and LV systolic pressure (LVSP), and the increases of LV volume in systole (LVVS), LV volume in diastole (LVVD), LV end-systolic diameter (LVESD) and LV end-diastolic diameter (LVEDD) in MI rats were improved by alarin treatment. The increases in the expression levels of collagen I, collagen III, and transforming growth factor (TGF)-ß were inhibited by alarin treatment in CFs and in the hearts of MI rats. The levels of NADPH oxidase (Nox) activity, superoxide anions and malondialdehyde (MDA) levels were increased, and the level of superoxide dismutase (SOD) activity was reduced in Ang II-treated CFs, which were reversed by alarin. Nox1 overexpression reversed the effects of alarin on attenuating the increases of collagen I, collagen III and TGF-ß expression levels induced by Ang II in CFs. These results indicated that alarin improved HF and cardiac fibrosis via inhibiting oxidative stress in HF rats. Nox1 played important roles in the regulation of alarin effects on attenuating CFs fibrosis induced by Ang II.

The circulating alarin level was elevated in infertile women with poor ovarian reserve.

OBJECTIVE: We aimed to reveal the association of serum alarin level with POR status of the infertile women in the present study. METHODS: The eligibility criteria for this prospective cross-sectional study included a total of 92 infertile women attending the Hitit University Hospital, and all participant women were categorized into two main groups of ovarian reserve: (i) Poor ovarian reserve (POR) group (n = 40) based on ESHRE consensus and (ii) Control group (NOR) (n = 52). RESULTS: The mean adjusted-ages and BMI values of the NOR and POR groups were statistically comparable (p = .057 and p = .600, respectively). The mean E2, FSH, and LH levels were elevated in the POR group (p < .001, for all). The mean AFC and AMH concentration were significantly reduced in the POR group (p < .001, for both). In addition, there was a significant increase in the serum alarin level in the POR group (p < .001). Pearson's analysis revealed that the mean BMI value of the POR group had a weak and negative correlation (r = 0.318, p = .046). Also, there was no correlation between serum alarin with E2 and FSH levels in both study groups. A weak and positive correlation was found between serum alarin and LH concentration only in the POR group (r = 0.318, p = .045). The mean AMH and AFC values were not significantly correlated with serum alarin levels. CONCLUSION: The circulating alarin level was significantly elevated in infertile women with POR patterns. In addition, the alarin level was significantly correlated with the serum LH concentration in the POR pattern.

Alarin in different human intestinal epithelial cell types.

Alarin (AL), a new member of the galanin family, has been localized in various CNS regions, mainly in rodents. Among other effects, it modulates food intake. Therefore, we analyzed the immunohistochemical distribution pattern of AL in human intestinal epithelia. Cryosections of 12 human bowel samples were immunohistochemically double-stained for AL and α-defensin 5 (αD; first set). Two further sets of sections were quadruple-stained either (second set) for AL, chromogranin (CG), synaptophysin (SY), and somatostatin (SO) or (third set) for AL, CG, Peptide Y (PY), and 5-hydroxytryptamine (5-HT). Slides were digitized and quantitative analysis of co-localization rates was undertaken. Small bowel: most of AL-positive cells (56%) were αD-positive Paneth cells located within the base of the crypts (first set). In the second set, about 27% of AL-labeled cells were co-reactive for SY and CG, likely representing entero-endocrine cells. In the third set, the largest subpopulation of AL-positive cells was not co-reactive for other markers applied (89%); most of them were likely Paneth cells. Large bowel: co-localization of AL with αD was not detected (first set). In the second set, AL was frequently co-localized with the other three markers applied (68%). In the third set, AL was frequently co-localized with 5-HT and CG (31%) as well as with PY and 5-HT (22%). Due to its presence in various enteroendocrine as well as Paneth cells, AL may be involved in different physiological and pathological processes.

NPR-9, a Galanin-Like G-Protein Coupled Receptor, and GLR-1 Regulate Interneuronal Circuitry Underlying Multisensory Integration of Environmental Cues in Caenorhabditis elegans.

C. elegans inhabit environments that require detection of diverse stimuli to modulate locomotion in order to avoid unfavourable conditions. In a mammalian context, a failure to appropriately integrate environmental signals can lead to Parkinson's, Alzheimer's, and epilepsy. Provided that the circuitry underlying mammalian sensory integration can be prohibitively complex, we analyzed nematode behavioral responses in differing environmental contexts to evaluate the regulation of context dependent circuit reconfiguration and sensorimotor control. Our work has added to the complexity of a known parallel circuit, mediated by interneurons AVA and AIB, that integrates sensory cues and is responsible for the initiation of backwards locomotion. Our analysis of the galanin-like G-protein coupled receptor NPR-9 in C. elegans revealed that upregulation of galanin signaling impedes the integration of sensory evoked neuronal signals. Although the expression pattern of npr-9 is limited to AIB, upregulation of the receptor appears to impede AIB and AVA circuits to broadly prevent backwards locomotion, i.e. reversals, suggesting that these two pathways functionally interact. Galanin signaling similarly plays a broadly inhibitory role in mammalian models. Moreover, our identification of a mutant, which rarely initiates backwards movement, allowed us to interrogate locomotory mechanisms underlying chemotaxis. In support of the pirouette model of chemotaxis, organisms that did not exhibit reversal behavior were unable to navigate towards an attractant peak. We also assessed ionotropic glutamate receptor GLR-1 cell-specifically within AIB and determined that GLR-1 fine-tunes AIB activity to modify locomotion following reversal events. Our research highlights that signal integration underlying the initiation and fine-tuning of backwards locomotion is AIB and NPR-9 dependent, and has demonstrated the suitability of C. elegans for analysis of multisensory integration and sensorimotor control.

[Level of circulating Alarin in obese children and its association with insulin resistance].

OBJECTIVE: To study the level of circulating Alarin in obese children and its association with various metabolic parameters. METHODS: A total of 86 obese children with a body mass index (BMI) above the 95th percentile were enrolled as the obesity group, and 82 healthy children, matched for age and sex, with a BMI below the 85th percentile were enrolled as the healthy control group. According to the presence or absence of insulin resistance (IR), the obesity group was further divided into an IR group with 27 children and a non-IR group with 59 children. Related anthropometric parameters, including body height, body weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP), were measured, and BMI was calculated. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), uric acid (UA), fasting insulin (FINS), and fasting blood glucose (FBG) were measured. The area under the receiver operating characteristic curve (AUC) for glucose and insulin, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), and whole-body insulin sensitivity index (WBISI) were calculated. ELISA was used to measure the level of circulating Alarin. RESULTS: The obesity group had a significantly higher level of circulating Alarin than the healthy control group (P<0.01). The IR group had a significantly higher level of circulating Alarin than the non-IR group (P<0.01). Circulating Alarin was positively correlated with BMI, TG, FBG, AUC-glucose, AUC-FINS, and HOMA-IR (P<0.05) and was negatively correlated with WBISI (P<0.05). The circulating Alarin level had a linear regression relationship with BMI, FBG, and HOMA-IR, among which HOMA-IR had the greatest influence on the circulating Alarin level (P<0.05). CONCLUSIONS: There is a significant increase in the circulating Alarin level in obese children, which may be associated with the development of obesity and IR.

High Circulating Alarin Levels Are Associated with Presence of Metabolic Syndrome.

BACKGROUND/AIMS: Alarin has been reported to be related with increased food intake and body weight. The relationship of circulating Alarin with insulin resistance or metabolic syndrome (MetS), however, is unknown. This study aimed to investigate the physiological role of Alarin and its association with MetS in humans. METHODS: Newly diagnosed MetS patients (n=237) and age-matched healthy subjects (n=192) were recruited for this study. Oral glucose tolerance test, treadmill exercise, lipid infusions and euglycemic-hyperinsulinemic clamp (EHCs) were performed. Circulating Alarin and TNFα levels were measured by ELISA. RESULTS: Circulating Alarin levels were significantly higher in MetS patients compared with healthy subjects (0.46 ± 0.22 vs. 0.41 ± 0.14 µg/L, P < 0.01). In all studied subjects, circulating Alarin levels were positively correlated with WC, blood pressure, FBG, triglyceride, HbA1c, HOMA-IR, AUCglucose, and TNFα (P < 0.05 or P < 0.01). Multivariate logistic regression analyses revealed that circulating Alarin levels were correlated with MetS and insulin resistance. There was no significant change of circulating Alarin levels in the subjects with treadmill exercise for 45 min. In healthy individuals, however, glucose challenge, acute hyperglycemia and lipid infusions resulted in increased circulating Alarin levels, while acute hyperinsulinaemia transiently decreased circulating Alarin levels. CONCLUSION: The present study provides the evidence that circulating Alarin levels are associated with MetS and insulin resistance.

Alarin in cranial autonomic ganglia of human and rat.

Extrinsic and intrinsic sources of the autonomic nervous system contribute to choroidal innervation, thus being responsible for the control of choroidal blood flow, aqueous humor production or intraocular pressure. Neuropeptides are involved in this autonomic control, and amongst those, alarin has been recently introduced. While alarin is present in intrinsic choroidal neurons, it is not clear if these are the only source of neuronal alarin in the choroid. Therefore, we here screened for the presence of alarin in human cranial autonomic ganglia, and also in rat, a species lacking intrinsic choroidal innervation. Cranial autonomic ganglia (i.e., ciliary, CIL; pterygopalatine, PPG; superior cervical, SCG; trigeminal ganglion, TRI) of human and rat were prepared for immunohistochemistry against murine and human alarin, respectively. Additionally, double staining experiments for alarin and choline acetyltransferase (ChAT), tyrosine hydroxilase (TH), substance P (SP) were performed in human and rat ganglia for unequivocal identification of ganglia. For documentation, confocal laser scanning microscopy was used, while quantitative RT-PCR was applied to confirm immunohistochemical data and to detect alarin mRNA expression. In humans, alarin-like immunoreactivity (alarin-LI) was detected in intrinsic neurons and nerve fibers of the choroidal stroma, but was lacking in CIL, PPG, SCG and TRI. In rat, alarin-LI was detected in only a minority of cranial autonomic ganglia (CIL: 3.5%; PPG: 0.4%; SCG: 1.9%; TRI: 1%). qRT-PCR confirmed the low expression level of alarin mRNA in rat ganglia. Since alarin-LI was absent in human cranial autonomic ganglia, and only present in few neurons of rat cranial autonomic ganglia, we consider it of low impact in extrinsic ocular innervation in those species. Nevertheless, it seems important for intrinsic choroidal innervation in humans, where it could serve as intrinsic choroidal marker.

[Galanin-like peptide (GALP): localization, receptors and biological function]. / Peptyd galaninopodobny (GALP): wystepowanie, receptory i funkcja biologiczna.

Galanin-like peptide (GALP) was isolated from porcine hypothalamus in 1999 on the basis of its ability to activate galanin receptors in vitro. Extensive studies carried out since the discovery of GALP contributed to the significant progress in our knowledge regarding this neuropeptide. GALP is synthesized mainly in the neurons of the hypothalamic arcuate nucleus and in the pituicytes of the posterior pituitary. The effects of GALP are mediated by well-characterized G-protein coupled galanin receptor subtypes. The fact that GALP shares homology only with 13 amino acids of the galanin sequence suggests that it might also interact with its own specific receptor. This relatively small 60-amino acid peptide belongs to a growing list of neuropeptides that play a crucial role in the regulation of food intake, energy balance and the reproductive axis. This peptide appears to be involved in integrating energy balance control and reproduction. The paper presents the current state of knowledge about the biosynthesis, structure, localization of GALP and its receptors, with particular emphasis on its role. This review will attempt to summarize the significant body of in vitro and in vivo studies conducted so far, concerning the effects of GALP.

Effect of Intracerebroventricular Administration of Galanin-Like Peptide on Hepatokines in C57BL/6 J Mice.

Galanin-like peptide (GALP) is a neuropeptide that was first isolated and identified from the porcine hypothalamus. Studies have described an anti-obesity effect of GALP. We previously found that intracerebroventricular administration of GALP in mice resulted in an increase in respiratory exchange rate 12 to 16 h later. GALP may also affect glucose metabolism, but the detailed mechanism has not been elucidated. In this study, we investigated the effects of GALP on glucose and lipid metabolism in the liver. Nine-week-old male C57BL / 6 J mice were administered a single intracerebroventricular dose of saline or GALP and dissected 16 h later. There were no significant between-group differences in body weight and blood glucose levels. With regard to gene and protein expression, G6Pase associated with hepatic gluconeogenesis was significantly reduced in the GALP group. In addition, the hepatokines selenoprotein P and fetuin-A, which induce insulin resistance in the liver, were significantly decreased in the GALP group. These results suggest that intracerebroventricular administration of GALP decreases the expression of key hepatokines, thereby enhancing glucose metabolism.

Alarin potentiates ongoing epileptiform activity in rat brain slices: an in vitro electrophysiological study.

Alarin is a newly discovered neuropeptide that belongs to the galanin peptide family with a wide range of bioactivity in the nervous system. Its function in the brain's autonomic areas has been studied, and it has been reported that alarin is involved in the regulation of excitability in hypothalamic neurons. Its role in the regulation of excitability in the hippocampus, however, is unknown. In this study, we investigated if alarin induced any synchronous discharges or epileptiform activity, and if it had any effect on already initiated epileptiform discharges. We used thick acute horizontal hippocampal slices obtained from 30­ to 35­day­old rats. Extracellular field potential recordings were evaluated in the CA1 region of the hippocampus. Our data demonstrated that, alarin application did not result in any epileptiform activity or abnormal discharges. 4­aminopyridine was applied to induce epileptiform activity in the slices. We found that alarin increased the frequency of interictal­like events and the mean power of local field potentials in the CA1 region of the hippocampus, which was induced by 4­aminopyridine. These results demonstrated for the first time that alarin has a modulatory effect on synchronized neuronal discharges and showed the contribution of the neuropeptide alarin to epilepsy­like conditions.

Alarin but not its alternative-splicing form, GALP (Galanin-like peptide) has antimicrobial activity.

Alarin is an alternative-splicing form of GALP (galanin-like peptide). It shares only 5 conserved amino acids at the N-terminal region with GALP which is involved in a diverse range of normal brain functions. This study seeks to investigate whether alarin has additional functions due to its differences from GALP. Here, we have shown using a radial diffusion assay that alarin but not GALP inhibited the growth of Escherichia coli (strain ML-35). The conserved N-terminal region, however, remained essential for the antimicrobial activity of alarin as truncated peptides showed reduced killing effect. Moreover, alarin inhibited the growth of E. coli in a similar potency as human cathelicidin LL-37, a well-studied antimicrobial peptide. Electron microscopy further showed that alarin induced bacterial membrane blebbing but unlike LL-37, it did not cause hemolysis of erythrocytes. In addition, alarin is only active against the gram-negative bacteria, E. coli but not the gram-positive bacteria, Staphylococcus aureus. Thus, these data suggest that alarin has potentials as an antimicrobial and should be considered for the development in human therapeutics.

Distribution of the regulatory peptide alarin in the eye of various species.

Alarin is a recently discovered regulatory peptide with vasoconstrictive properties in murine skin. Control of vasoconstriction/-relaxation is essential for ocular blood flow and hence the eye's homeostasis, and regulatory peptides are involved in regulation of ocular blood flow. Here we describe the existence and distribution of alarin in the eye of human and potential experimental animals (rat, mouse). Eyes of rat, mouse, and human were prepared for immunohistochemistry against murine and human alarin, respectively. Additionally, double staining experiments for alarin and CD31 were performed in human choroidal flat-mount preparations. For documentation, confocal laser scanning microscopy was used while quantitative real-time-PCR was applied to confirm immunohistochemical data and to detect alarin mRNA expression in human retina and choroid. Alarin-like immunoreactivity (alarin-LI) was detected in corneal epi- and endothelium of human, mouse, and rat, as well as in the conjunctiva of mouse and rat. Alarin-LI was found in the iris of all the species investigated and, in humans, was concentrated around blood vessels. All three species showed distinctive alarin-LI in the non-pigmented epithelium of the ciliary body. In the retina of mouse and rat, maximum signals were detected in the outer nuclear and ganglion cell layer, whereas in humans a strong alarin-LI was found around retinal blood vessels and in intrinsic choroidal neurons (ICN). Quantitative RT-PCR in human confirmed alarin mRNA expression retina and choroid. The existence of alarin in cornea and conjunctiva might indicate a role in immune defense, while its presence in the non-pigmented ciliary epithelium favors an involvement in aqueous humor production. Alarin around blood vessels/in ICN might indicate an involvement in ocular blood flow regulation. Since alarin is found widely distributed in the eyes of species investigated, we were able to establish the basis for further functional experiments.

Expression of alarin in ependymoma and choroid plexus tumors.

Alarin, a 25 amino acid splice variant of the galanin-like peptide, was originally discovered in gangliocytes of neuroblastic tumors and shown to be expressed in ganglioneuroblastoma and ganglioneuroma but not in undifferentiated neuroblastoma. Recently, in vivo studies have elucidated the physiological functions of alarin in the central nervous system (CNS). Alarin was shown to stimulate food intake, increase body weight, induce luteinizing hormone secretion and stimulate fos-expression in rats; the anatomical localization for these functions correlates well with the varied distribution of the alarin peptide in the brain. Because alarin was originally detected in neuroblastic tumors and is present in a wide range of nuclei in the CNS, we determined in the present study the expression of alarin in a variety of CNS tumors. Immunohistochemical analysis of 179 tumor samples resulted in different alarin-like immunoreactivity (alarin-LI) intensities, which were score-rated from 0 (no alarin stainin), 1 (low intensity), 2 (medium intensity) to 3 (high intensity). Immunohistochemical analyses revealed score 2 or 3 alarin-LI in all choroid plexus tumors (100 %, 7/7) and in the majority of ependymomas (90 %, 52/58), but only in a minority of astrocytomas (15 %, 5/33), meningiomas (14 %, 7/49) and tumors of the cranial nerves (7 %, 1/15). In oligodendrogliomas (0 %, 0/12) and oligoastrocytoma (0 %, 0/5) alarin-LI was not detectable. The high specificity (83 %) of alarin-LI suggests that it might be used as a diagnostic marker for ependymoma in differentiating them from other gliomas such as astrocytomas and oligodendrogliomas.

Identification of the promoter region and genetic mutations of the porcine GALP gene.

Galanin-like peptide (GALP) gene, encoding a member of the galanin family of neuropeptides involved in reproduction, was differentially expressed in PMSG-hCG stimulated pre-ovulatory ovarian follicles of Chinese Taihu and Large White sows in our previous study. In the present study, promoter region and genetic mutations of the porcine GALP gene were determined. A 1,322 bp contig in 5'-flanking region was predicted to contain 5 potential transcription promoters by Neural Network Promoter Prediction version 2.2. 5'-deletion expression in both CHO and hela cells showed that there were a negative regulatory element at -852 to -803 bp and a positive regulatory element at -1,318 to -1,269 bp. Comparative sequence analyses of Chinese Taihu and Large White GALP gene sequence revealed the c.*27C>G mutation in the 3'-UTR and the c.88-1225C>G mutation in intron 1, which can be detected by HhaI and AluI PCR-RFLP, respectively. The association analysis with litter size traits showed that at both loci CC and GG genotypes were different for NBA for all parities in DIV pigs (P < 0.05). However, two SNPs were not in significant linkage disequilibrium analyzed using SHEsis online software, and could be used in pig breeding individually.

Positive allosteric modulators to peptide GPCRs: a promising class of drugs.

The task of finding selective and stable peptide receptor agonists with low molecular weight, desirable pharmacokinetic properties and penetrable to the blood-brain barrier has proven too difficult for many highly coveted drug targets, including receptors for endothelin, vasoactive intestinal peptide and galanin. These receptors and ligand-gated ion channels activated by structurally simple agonists such as glutamate, glycine and GABA present such a narrow chemical space that the design of subtype-selective molecules capable of distinguishing a dozen of glutamate and GABA receptor subtypes and possessing desirable pharmacokinetic properties has also been problematic. In contrast, the pharmaceutical industry demonstrates a remarkable success in developing 1,4-benzodiazepines, positive allosteric modulators (PMAs) of the GABAA receptor. They were synthesized over 50 years ago and discovered to have anxiolytic potential through an in vivo assay. As exemplified by Librium, Valium and Dormicum, these allosteric ligands of the receptor became the world's first blockbuster drugs. Through molecular manipulation over the past 2 decades, including mutations and knockouts of the endogenous ligands or their receptors, and by in-depth physiological and pharmacological studies, more peptide and glutamate receptors have become well-validated drug targets for which an agonist is sought. In such cases, the pursuit for PAMs has also intensified, and a working paradigm to identify drug candidates that are designed as PAMs has emerged. This review, which focuses on the general principles of finding PAMs of peptide receptors in the 21st century, describes the workflow and some of its resulting compounds such as PAMs of galanin receptor 2 that act as potent anticonvulsant agents.

Galanin-like peptide and its correlation with androgen levels in patients with polycystic ovary syndrome.

INTRODUCTION: We aimed to investigate serum galanin-like peptide (GALP) levels and their correlation with hormonal and metabolic parameters in patients with polycystic ovary syndrome (PCOS). MATERIAL AND METHODS: The study included 48 women (age range, 18-44 years) with a diagnosis of PCOS, and a control group that included 40 healthy females (age range, 18-46 years). Waist circumference, body mass index (BMI), and Ferriman-Gallwey score were evaluated and plasma glucose, lipid profile, oestradiol, progesterone, total testosterone, prolactin, insulin, dehydroepiandrosterone sulphate (DHEA-S), follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), 25-hydroxyvitamin D (25(OH)D), fibrinogen, d-dimer, C-reactive protein (CRP), and GALP levels were measured in all study subjects. RESULTS: Waist circumference (p = 0.044) and Ferriman-Gallwey score (p = 0.002) were significantly higher in patients with PCOS compared to the control group. Among the metabolic and hormonal parameters studied, only total testosterone was significantly higher in patients with PCOS (p = 0.002). Also, the serum 25(OH)D level was significantly lower in the PCOS group (p = 0.001). CRP, fibrinogen, and D-dimer levels were all similar between the 2 groups. Serum GALP level was significantly higher in PCOS patients (p = 0.001). GALP was negatively correlated with 25(OH)D (r = -0.401, p = 0.002) and positively correlated with total testosterone values (r = 0.265, p = 0.024). Multiple regression analysis revealed that both total testosterone and 25(OH)D significantly contributed to GALP levels. CONCLUSIONS: Our study is the first in the literature to evaluate serum GALP levels in patients with PCOS. Increased GALP levels in PCOS and its association with total testosterone levels might show that GALP can act as an intermediary in increased GnRH-mediated LH release, which is one of the underlying pathogenetic mechanism of PCOS.