• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6215-6220
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• 2013

Kisspeptins (KPs) encoded by the KiSS-1 gene are C-terminally amidated peptide products, including KP-10, KP-13, KP-14 and KP-54, which are endogenous agonists for the G-protein coupled receptor-54 (GPR54). Functional analyses have demonstrated fundamental roles of KiSS-1 in whole body homeostasis including sexual differentiation of brain, action on sex steroids and metabolic regulation of fertility essential for human puberty and maintenance of adult reproduction. In addition, intensive recent investigations have provided substantial evidence suggesting roles of Kisspeptin signalling via its receptor GPR54 in the suppression of metastasis with a variety of cancers. The present review highlights the latest studies regarding the role of Kisspeptins and the KiSS-1 gene in tumor progression and also suggests targeting the KiSS-1/GPR54 system may represent a novel therapeutic approach for cancers. Further investigations are essential to elucidate the complex pathways regulated by the Kisspeptins and how these pathways might be involved in the suppression of metastasis across a range of cancers.

• Development and Reproduction
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• v.9 no.1
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• pp.1-5
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• 2005

The hypothalamo-pituitary-gonadal hormone axis is centrally controlled by a complex regulatory network of excitatory and inhibitory signals, that is dormant during infantile and juvenile periods and activated at puberty. The kisspeptins are the peptide products of the KiSS-1 gene and the endogenous agonists for the G protein-coupled receptor 54(GPR54). Although KiSS-1 was initially discovered as a metastasis suppressor gene, a recent evidence suggests the KiSS-1/GPR54 system is a key regulator of the reproductive system. Yet the actual role of the KiSS-1/GPR54 system in the neuroendocrine control of gonadotropin secretion remains largely unexplored, the system could be the first missing link in the reproductive hormonal axis. Central or peripheral administration of kisspeptin stimulates the hypothalamic-pituitary-gonadal axis, increasing circulating gonadotropin levels in rodents, sheep, monkey and human models. These effects appear likely to be mediated via the hypothalamic GnRH neuron system, although kisspeptins may have direct effects on the anterior pituitary gland. The loss of function mutations of the GPR54(GPR54-/-) have been associated with lack of puberty onset and idiopathic hypogonadotropic hypogonadism(IHH). So kisspeptin infusion may provide a novel mechanism for HPG axis manipulation in disorders of the reproductive system.

• Development and Reproduction
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• v.16 no.2
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• pp.121-128
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• 2012

Kisspeptin has been reported to facilitate sexual maturation and ovulation by directly stimulating GnRH neurons via its receptor, GPR54. The KiSS-GPR54 system is playing an important role in the reproduction of several mammalian species. However, little is known about their function in fish. The aim of this study is to understand the physiological function and evolutionary conservation of KiSS-GPR54 system in teleost fish blacktip grouper, Epinephelus fasciatus. In the present study, we have partial cloned KiSS1, KiSS2 GPR54 mRNAs from a brain samples. Tissue distribution analysis using RT-PCR revealed that the KiSS1, KiSS2, GPR54 transcripts were expressed in different tissue. The KiSS-GPR54 system in gonadal of immature and mature stage were analyzed using qRT-PCR. The partial sequence of KiSS1, KiSS2, GPR54 were 232 bp, 304 bp, 613 bp long, respectively. KiSS1, KiSS2, GPR54 mRNAs are shown common expression in the brain. The amount of KiSS1, KiSS2 mRNAs expression were significantly higher in mature stage than immature stage. However GPR54 mRNA expression was higher in immature stage. These results are in good agreement with the hypothesis that KiSS-GPR54 system plays an important role in the regulation of reproductive function in the blacktip grouper.

• Development and Reproduction
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• v.26 no.3
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• pp.107-115
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• 2022

Kisspeptins, products of KISS1 gene, are ligands of the G-protein coupled receptor (GPR54), and the kisspeptin-GPR54 signaling has an important role as an upstream regulator of gonadotropin releasing hormone (GnRH) neurons. Interestingly, extrahypothalamic expressions of kisspeptin/GPR-54 in gonads have been found in primates and experimental rodents such as rats and mice. Hamsters, another potent experimental rodent, also have a kisspeptin-GPR54 system in their ovaries. The presence of testicular kisspeptin-GPR54 system, however, remains to be solved. The present study was undertaken to determine whether the kisspeptin is expressed in hamster testis. To do this, reverse transcription-polymerase chain reactions (RT-PCRs) and immunohistochemistry (IHC) were employed. After the nest PCR, two cDNA products (320 and 280 bp, respectively) were detected by 3% agarose gel electrophoresis, and sequencing analysis revealed that the 320 bp product was correctly amplified from hamster kisspeptin cDNA. Modest immunoreactive (IR) kisspeptins were detected in Leydig-interstitial cells, and the weak signals were detected in germ cells, mostly in round spermatids and residual bodies of elongated spermatids. In the present study, we found the kisspeptin expression in the testis of Syrian hamster. Further studies on the local role(s) of testicular kisspeptin are expected for a better understanding the physiology of hamster testis, including photoperiodic gonadal regression specifically occurred in hamster gonads.

• Development and Reproduction
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• v.16 no.1
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• pp.31-38
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• 2012

Kisspeptin has been implicated in the process of puberty onset in various animal groups. This peptide is encoded by a gene, Kiss1 in avian and mammalian species. Contrary to these higher vertebrates, however, fish appeared to have another gene, Kiss2 that also codes for the precursor peptide of kisspeptin. To figure out biological significance of this gene during the puberty onset in fish, the expression profile of Kiss2 gene was investigated in the brain of Nile tilapia together with genes of GPR54, GnRH receptorI (rGnRHI) and GTH subunits ($LH{\beta}$ and $FSH{\beta}$). Expression of Kiss2 mRNA significantly increased at 2 weeks post hatch (wph) and 13 wph ($P$<0.05). This increase coincided with the increases of GPR54 and rGnRH I gene expression. Detection of $LH{\beta}$ and $FSH{\beta}$ subunit gene expression was possible later than 13 wph, indicating the activation of gonadotrophs in the pituitary. Data obtained from this study strongly suggest that, in addition to Kiss1 gene, Kiss2 gene is deeply associated with the onset of puberty by the activation of hypothalamus pituitary gonadal axis in Nile tilapia.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.48-54
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• 2022

GPR43 (also known as FFAR2), a metabolite-sensing G-protein-coupled receptor stimulated by short-chain fatty acid (SCFA) ligands is involved in innate immunity and metabolism. GPR43 couples with Gα_i/o and Gα_q/11 heterotrimeric proteins and is capable of decreasing cyclic AMP and inducing Ca²⁺ flux. The GPR43 receptor has additionally been shown to bind β-arrestin 2 and inhibit inflammatory pathways, such as NF-κB. However, GPR43 shares the same ligands as GPR41, including acetate, propionate, and butyrate, and determination of its precise functions in association with endogenous ligands, such as SCFAs alone, therefore remains a considerable challenge. In this study, we generated novel synthetic agonists that display allosteric modulatory effects on GPR43 and downregulate NF-κB activity. In particular, the potency of compound 187 was significantly superior to that of pre-existing compounds in vitro. However, in the colitis model in vivo, compound 110 induced more potent attenuation of inflammation. These novel allosteric agonists of GPR43 clearly display anti-inflammatory potential, supporting their clinical utility as therapeutic drugs.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8
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• pp.1104-1111
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• 2019

Objective: The aim of this study was to detect single nucleotide polymorphisms (SNP) of G protein-coupled receptor 54 (GPR54) gene and explore association of this candidate gene with reproductive traits in Jiaxing Black sows. Methods: Six pairs of primers of the gene were designed to amplify all exons thus sequences of which were detected by means of direct sequencing and then SNP loci were scanned. The effects of SNPs on total number of piglets born (TNB), number of piglets born alive (NBA), number of still born piglets (NSB), and litter weight at birth (LWB) of Jiaxing Black sows were analyzed. Results: Three SNP loci, including T3739C, C3878T and T6789C, were identified via comparison of sequencing and two genotypes (AB, BB) at each SNP site were observed. T3739C resulted in the change of amino acid ($Leu{\rightarrow}Pro$) in corresponding protein, and C3878T resulted in synonymous mutation ($Ile{\rightarrow}Ile$). Statistical results demonstrated that allele B was the preponderant allele at the three SNP loci and Genotype BB was the preponderant genotype. Meanwhile, Chi-Square test of these three SNPs indicated that all mutation sites fitted in Hardy-Weinberg equilibrium (p>0.05). For GPR54-T3739C locus, Jiaxing Black sows with genotype BB had 1.23 TNB and 1.28 NBA (p<0.01) that were more than those with genotype AB, respectively. Jiaxing Black sows that had the first two parities with genotype BB had additional 2.23 TNB, 2.27 NBA (p<0.01), and 1.94 LWB (p<0.05) compared to those with genotype AB, respectively. However, for other two loci, no significant difference was found between TNB, NBA, NSB, and LWB, and different genotypes of Jiaxing Black sows. Conclusion: In conclusion, the polymorphisms of GPR54-T3739C locus were significantly associated to TNB, NBA, and LWB and could be used as a potential genetic marker to improve reproductive function of Jiaxing black sows.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.211-220
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• 2015

We investigated the differences in the expression of the neurohormones kisspeptin (Kiss) and gonadotropin-inhibitory hormone (GnIH) and cytochrome P450 aromatase (P450arom), gonadotropin hormones (GTHs), and sex steroids in the goldfish Carassius auratus exposed to light-emitting diodes (LEDs). The expression levels of Kiss1, Kiss2, G-protein-coupled receptor 54 (GPR54), GTHs, GnIH, and P450arom were compared between the control (white light) and LED-treated goldfish. Furthermore, we measured the plasma levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The levels of Kiss1 mRNA and protein; Kiss2, GPR54, and $GTH{\alpha}$ protein; GTH mRNA; and plasma FSH and LH in the hypothalamus and cultured hypothalamus cells were significantly higher in the green and purple LED treatment groups than in the other groups. These results suggested that red LEDs inhibit the sex maturation hormones, Kiss, GPR54, GTHs, and P450arom, and that GnIH plays a role in the negative regulation of reproductive function in goldfish.

• Journal of Integrative Natural Science
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• v.9 no.2
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• pp.136-143
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• 2016

KiSS1-derived peptide receptor, a GPCR protein, binds with the hormone kiss peptin. They are important in the neuroendocrine regulation of reproduction and in the secretion of gonadotrophin-releasing hormone. Thus, analysing the structural features of the receptor becomes important. However, the three dimensional structure of the protein is unavailable. Hence in this study, we have performed the homology modelling of KiSS1-derived peptide receptor with 5 different templates. 30 models were constructed using two platforms - Easymodeller and ITasser. The optimal models were chosen based on the model validation. Two models were selected after validation. The developed models could provide useful for analysing the structural features of KiSS1-derived peptide receptor and their pathophysiological role in various disorders related to them.

• Journal of Integrative Natural Science
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• v.9 no.4
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• pp.234-240
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• 2016

Bradykinin receptor B2, a GPCR protein, binds with the inflammatory mediator hormone bradkynin. It plays an important role in cross-talk between the renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS). Also, it is involved in many processes including vasodilation, edema, smooth muscle spasm and pain fiber stimulation. Hence, studuying the structural features of the receptor becomes important. But the unavailability of the three dimensional structure of the protein makes the analysis difficult. Hence we have performed the homology modelling of Bradykinin receptor B2 with 5 different templates. 25 different homology models were constructed. Two best models were selected based on the model validation. The developed models could be helpful in analysing the structural features of Bradykinin receptor B2 and in pathophysiology of various disorders related to them.