Kiss1 mRNA Expression Research Articles

SAT-415 Action of Neurotensin, CRH, And RFRP-3 in E2-Induced Negative Feedback Control: Studies Using a Mouse Arc Hypothalamic Cell Model

The recently established immortalized hypothalamic cell model mHypoA-55 possesses characteristics similar to those of Kiss-1 neurons in the arcuate nucleus (ARC) region of the hypothalamus. Here, we show that Kiss-1 gene expression in these cells was downregulated by 17β-estradiol (E2) under certain conditions. Both neurotensin (NT) and corticotropin-releasing hormone (CRH) were expressed in these cells and upregulated by E2. Stimulation of mHypoA-55 cells with NT and CRH significantly decreased Kiss-1 mRNA expression. A mammalian gonadotropin-inhibitory hormone homolog, RFamide-related peptide-3 (RFRP-3), was also found to be expressed in mHypoA-55 cells, and RFRP-3 expression in these cells was increased by exogenous melatonin stimulation. E2 stimulation also upregulated RFRP-3 expression in these cells. Stimulation of mHypoA-55 cells with RFRP-3 significantly increased the expression of NT and CRH. Furthermore, melatonin stimulation resulted in the increase of both NT and CRH mRNA expression in mHypoA-55 cells. On the other hand, in experiments using mHypoA-50 cells, which were originally derived from hypothalamic neurons in the anteroventral periventricular nucleus, Kiss-1 gene expression was upregulated by both NT and CRH, although E2 increased both NT and CRH expression, similarly to the mHypoA-55 cells. Our observations using the hypothalamic ARC cell model mHypoA-55 suggest that NT and CRH have inhibitory effects on Kiss-1 gene expression under the influence of E2 in association with RFRP-3 expression. Thus, these neuropeptides might be involved in E2-induced negative feedback mechanisms.

Long noncoding RNA LUCAT1 promotes migration and invasion of prostate cancer cells by inhibiting KISS1 expression.

Recent researches have revealed the role of long noncoding RNAs (lncRNAs) in tumor development. In this study, the potential function of lncRNA LUCAT1 in the progression of prostate cancer was identified. Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was used to detect LUCAT1 expression in both prostate cancer cells and tissue samples. Moreover, the association between LUCAT1 expression level and overall survival of prostate cancer patients was analyzed. In addition, wound healing assay and transwell assay were conducted to evaluate the regulatory effect of LUCAT1 on prostate cancer cells. Furthermore, the underlying mechanism of LUCAT1 in regulating the development of prostate cancer was explored via qRT-PCR and Western blot. LUCAT1 expression was much higher in prostate cancer samples than controls. Besides, LUCAT1 expression was correlated with the overall survival of prostate cancer patients. Moreover, LUCAT1 overexpression promoted in vitro migration and invasion of prostate cancer cells. In addition, the mRNA and protein expression of KISS1 were downregulated after LUCAT1 overexpression. Furthermore, it was found that the expression level of KISS1 was negatively related to the expression level of LUCAT1 in prostate cancer tissues. LUCAT1 could enhance migration and invasion of prostate cancer cells by regulating KISS1, which might offer a potential therapeutic target for prostate cancer.

SU43EXAMINING THE ROLE OF SEX HORMONES IN POSTNATAL DEPRESSION AND MAJOR DEPRESSIVE DISORDER: POLYGENIC RISK SCORES AND HIPPOCAMPAL NEUROGENESIS

Early life exposure to endocrine disruptors is considered to disturb normal development of hormone sensitive parameters and contribute to advanced puberty and reduced fecundity in humans. Kisspeptin is a positive regulator of the hypothalamic–pituitary–gonadal axis, and plays a key role in the initiation of puberty. In the adult, Kiss1 gene expression occurs in two hypothalamic nuclei, namely the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (ARC), which are differentially regulated by peripheral sex steroid hormones. In this study we determined the effects on puberty onset and Kiss1 mRNA levels in each of the two nuclei after long-term perinatal exposure of rats to ethinyl oestradiol (EE2) or to five different pesticides, individually and in a mixture. Rat dams were per orally administered with three doses of EE2 (5, 15 or 50 μg/kg/day) or with the pesticides epoxiconazole, mancozeb, prochloraz, tebuconazole, and procymidone, alone or in a mixture of the five pesticides at three different doses. Kiss1 mRNA expression was determined in the AVPV and in the ARC of the adult male and female pups in the EE2 experiment, and in the adult female pups in the pesticide experiment.We find that perinatal EE2 exposure did not affect Kiss1 mRNA expression in this study designed to model human exposure to estrogenic compounds, and we find only minor effects on puberty onset. Further, the Kiss1 system does not exhibit persistent changes and puberty onset is not affected after perinatal exposure to a pesticide mixture in this experimental setting. However, we find that the pesticide mancozeb tends to increase Kiss1 expression in the ARC, presumably through neurotoxic mechanisms rather than via classical endocrine disruption, calling for increased awareness that Kiss1 expression can be affected by environmental pollutants through multiple mechanisms.

OR-006 Effect of Moderate-intensity Exercise on the Expression of Hypothalamic KiSS-1 and GPR54 mRNA in Diet Induced Obesity Rats

Objective To observe the effect of high fat diet on the hypothalamic expression of KiSS-1and the G-protein coupled receptor (GPR) 54 mRNA and explore the modulatory role of moderate-intensity exercise in the diet induced obesity male rats.
 Methods After 8 weeks high fat feeding, 20 obesity 11-weeks SD rats were randomly assigned to high-fat diet sedentary (FS, n=8) and high-fat diet exercise (FE, n=8) groups, 20 normal diet 11-weeks SD rats also were randomly assigned to sedentary (SS, n=8) and exercise (SE, n=8) groups. During the following 8 weeks, obesity rats were continued expose to high-fat-diet. SE and FE groups did the 60%-70%V(•)O2max treadmill training (5 days/week, 1 hour/day). The V(•)O2 max of exercise groups were remeasured every two weeks. The hypothalamic expression of KiSS-1 and GPR54 mRNA were tested in each group.
 Results 
 After the first 8-weeks high fat feeding, the obesity rats were heavier than normal diet group (491.74±26.19g vs. 410.05±45.77g, p<0.01). After 8-weeks training, the FE group was lighter than FS group (590.23±35.74g vs. 681±52.56, p<0.01). The FS group had higher hypothalamic expression of KiSS-1 mRNA (1.51±0.66 vs 0.75±0.27, p<0.05) and GPR54 mRNA (2.45±0.38 vs 0.61±0.15, p<0.01) than SS group. The FE group had lower hypothalamic expression of KiSS-1 mRNA (0.69±0.13, p>0.05) and GPR54 mRNA (0.58±0.10, p<0.01) than FS group.
 Conclusions 
 There is stimulating effect of high-fat diet induced obesity on hypothalamic expression of KiSS-1and GPR54 mRNA. 8-weeks 60%-70%V (•) O2max treadmill training could cure this effect.

Association between KISS1 rs5780218 promoter polymorphism and onset of growth hormone secreting pituitary adenoma

ObjectivesThis study analyzed the KISS1 c.-145delA (rs5780218) promoter polymorphism in a cohort of patients with growth hormone secreting pituitary adenoma (somatotropinoma) and controls, to investigate its role in the incidence of acromegaly and to assess patient/tumor characteristics.Material and methods rs5780218 allelic and genotypic distributions were compared between 49 somatotropinoma patients and 167 healthy controls. rs5780218 was also assessed in relation to patient characteristics and tumor aggressiveness, as characterized by tumor invasion and resistance to conventional therapy. The relationship between KISS1 mRNA expression and the rs5780218 genotype was also assessed in available pituitary tumor samples. ResultsThe homozygous -/- variant genotype was associated with high rates of somatotropinoma (P<0.01), but not with tumor invasiveness, patient characteristics or hormonal remission. KISS1 mRNA expression was much lower in somatotropinomas carrying the deleted allele than in homozygous wild type AA. ConclusionsIn this pilot study, the rs5780218 promoter polymorphism was evaluated in pituitary adenoma, and showed a possible association with the incidence of somatotropinoma but not with tumor progression.

Estrogenic-dependent glutamatergic neurotransmission from kisspeptin neurons governs feeding circuits in females.

The neuropeptides tachykinin2 (Tac2) and kisspeptin (Kiss1) in hypothalamic arcuate nucleus Kiss1 (Kiss1ARH) neurons are essential for pulsatile release of GnRH and reproduction. Since 17β-estradiol (E2) decreases Kiss1 and Tac2 mRNA expression in Kiss1ARH neurons, the role of Kiss1ARH neurons during E2-driven anorexigenic states and their coordination of POMC and NPY/AgRP feeding circuits have been largely ignored. Presently, we show that E2 augmented the excitability of Kiss1ARH neurons by amplifying Cacna1g, Hcn1 and Hcn2 mRNA expression and T-type calcium and h-currents. E2 increased Slc17a6 mRNA expression and glutamatergic synaptic input to arcuate neurons, which excited POMC and inhibited NPY/AgRP neurons via metabotropic receptors. Deleting Slc17a6 in Kiss1 neurons eliminated glutamate release and led to conditioned place preference for sucrose in E2-treated KO female mice. Therefore, the E2-driven increase in Kiss1 neuronal excitability and glutamate neurotransmission may play a key role in governing the motivational drive for palatable food in females.

Reduction of Kiss1 expression in the anteroventral periventricular nucleus is associated with atrazine-induced attenuation of the luteinizing hormone surge in female rats.

Atrazine, a commonly used herbicide, suppresses the luteinizing hormone (LH) surge in female rats, although the underlying mechanism remains unclear. Kisspeptin, encoded by the Kiss1 gene, is a hypothalamic peptide that controls gonadotropin-releasing hormone (GnRH) release from the GnRH neurons. Kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) are involved in regulating pre-ovulatory GnRH and LH surge. To clarify the effect of atrazine on the LH surge in female rats, we investigated its effects on hypothalamic GnRH and kisspeptin. Ovariectomized female rats in a high-dose estradiol supplementation model were orally administered vehicle or 100 mg/kg of atrazine once daily for 5 days. This attenuated the LH surge but did not affect baseline LH levels, with no difference in hypothalamic GnRH levels between the vehicle-treated and atrazine-treated animals. After the fifth treatment, subcutaneous administration of kisspeptin (at 0, 0.1, 1, and 10 nmol/kg) induced a dose-dependent LH release almost equivalent in the vehicle- and atrazine-treated animals, suggesting that GnRH neurons maintain normal responsiveness to kisspeptin. However, Kiss1 mRNA expression levels in the AVPV were significantly reduced in the atrazine-treated animals. Given the normal response of GnRH neurons to exogenously administered kisspeptin, the suppressive effect of atrazine may be explained by suppression of Kiss1 expression in the AVPV leading to the attenuation of kisspeptin release from kisspeptin neurons in the AVPV. Further studies are warranted to elucidate more precisely the mechanism of atrazine's involvement in the suppression of Kiss1 mRNA expression in the AVPV.

Action of neurotensin, corticotropin-releasing hormone, and RFamide-related peptide-3 in E2-induced negative feedback control: studies using a mouse arcuate nucleus hypothalamic cell model.

The recently established immortalized hypothalamic cell model mHypoA-55 possesses characteristics similar to those of Kiss-1 neurons in the arcuate nucleus (ARC) region of the hypothalamus. Here, we show that Kiss-1 gene expression in these cells was downregulated by 17β-estradiol (E2) under certain conditions. Both neurotensin (NT) and corticotropin-releasing hormone (CRH) were expressed in these cells and upregulated by E2. Stimulation of mHypoA-55 cells with NT and CRH significantly decreased Kiss-1 mRNA expression. A mammalian gonadotropin-inhibitory hormone homolog, RFamide-related peptide-3 (RFRP-3), was also found to be expressed in mHypoA-55 cells, and RFRP-3 expression in these cells was increased by exogenous melatonin stimulation. E2 stimulation also upregulated RFRP-3 expression in these cells. Stimulation of mHypoA-55 cells with RFRP-3 significantly increased the expression of NT and CRH. Furthermore, melatonin stimulation resulted in the increase of both NT and CRH mRNA expression in mHypoA-55 cells. On the other hand, in experiments using mHypoA-50 cells, which were originally derived from hypothalamic neurons in the anteroventral periventricular nucleus, Kiss-1 gene expression was upregulated by both NT and CRH, although E2 increased both NT and CRH expression, similarly to the mHypoA-55 cells. Our observations using the hypothalamic ARC cell model mHypoA-55 suggest that NT and CRH have inhibitory effects on Kiss-1 gene expression under the influence of E2 in association with RFRP-3 expression. Thus, these neuropeptides might be involved in E2-induced negative feedback mechanisms.

P62 Deficiency Leads to Hypogonadism and Infertility via Pituitary Functions Loss in Young Female Mice before Metabolic Disorders Onset

p62/SQSTM1 is an essential protein adaptor that fine-tunes numerous biological processes by autophagy or related cell signaling pathway. Previous studies have proved that p62 loss lead to mature-onset metabolic disorders including obesity, diabetes and fatty liver in adult mice; and in younger human being those metabolic diseases are close to reproductive dysfunctions, such as PCOS. Here, the metabolism and reproductive function of younger (8 weeks) p62 deficient female mice was observed, and hypothalamus-pituitary-ovary axis was evaluated to explore the possible upstream mechanisms. We found that although p62 deficiency rarely exposes obvious metabolic influences during younger stage of female mice, the deteriorative reproductive function has exhibited, such as attenuated breeding success rate and number of pups per litter. In particular, genetic deletion of p62 causes impaired estrous cycle, thread-like atrophied uteri and low-weight ovary with the lack of corpus luteum, failure of folliculogenesis and ovulation. Next, the low levels of plasma sex steroid hormone estradiol and gonadotropic luteinizing hormone (LH) have also been detected. Furthermore, defected steroidogenesis signaling including decreased StAR and P450scc in p62 KO ovary reveals reduced cholesterol-to-pregnenolone transition, meanwhile, increased Lhcgr mRNA expression in ovarian suggests a compensatory reaction. Consistent with lower serum LH level, significantly decreased mRNA expression of Lhb as well as slightly reduced Fshb also were found in the pituitary of p62 KO female mice. In addition, the elevated expression of Kiss1 mRNA in hypothalamus might discover the compensatory for pituitary function loss. Our findings support the vital role p62 of pituitary on reproductive function in younger individuals, and this effect might be the direct consequence rather than by metabolic disorders induced by p62 deficiency. Disclosure M. Long: None. H. Zheng: None. X. Li: None.

Enhancement of Melanocortin-4 Receptor (MC4R) and Constancy of Kiss1 mRNAs Expression in the Hypothalamic Arcuate Nucleus in a Model of Polycystic Ovary Syndrome Rat

Background: Hypothalamic Melanocortin-4 Receptor (MC4R) and kiss1/kisspeptin systems play roles in reproductive processes. This study was conducted to evaluate changes in MC4R and kiss1 genes expression in the arcuate nucleus (ARC) of the hypothalamus and its relationship with polycystic ovary syndrome (PCOS) in rats.Materials and Methods: In the current experimental study, 24 female rats were randomly and equally allocated into nulliparous and primiparous groups and then were divided into two subgroups of PCOS and control. PCOS was induced by exposure to continuous light. Sex-related hormones were evaluated by radioimmunoassay or immunoradiometric assay. Expressions of MC4R and kiss1 gene in the ARC of the hypothalamus of the rats were evaluated by real-time PCR. Histomorphometric alterations of ovaries were compared between groups.Results: Number of tertiary follicles and their size and number of atretic follicles in the PCOS subgroups were more than those in the controls (P&lt;0.05) whereas the number of secondary follicles and corpus luteum in the PCOS subgroups were lower than those in the controls (P&lt;0.05). Antrum and total diameters of tertiary follicles in the PCOS subgroups were greater and granulosa layer diameter was lower than those in the controls (P&lt;0.05). The MC4R mRNA expression in the PCOS subgroups was 6.5-fold in nulliparous and 3.5-fold in primiparous groups more than their controls’ pairs (P&lt;0.05). However, parity did not affect the expression of MC4R gene (P&gt;0.05).The kiss1 mRNA expression in the PCOS and control subgroups was not significantly different (P&gt;0.05).Conclusion: Overexpression of MC4R gene after PCOS induction in the ARC of the hypothalamus may link to metabolic disorders of induced PCOS in the rats. However, alteration in the kiss1 mRNA expression after PCOS induction was not observed in the rats. [GMJ.2018;7:e1070]

Enhancement of Melanocortin-4 Receptor (MC4R) and Constancy of Kiss1 mRNAs Expression in the Hypothalamic Arcuate Nucleus in a Model of Polycystic Ovary Syndrome Rat.

Background: Hypothalamic Melanocortin-4 Receptor (MC4R) and kiss1/kisspeptin systems play roles in reproductive processes. This study was conducted to evaluate changes in MC4R and kiss1 genes expression in the arcuate nucleus (ARC) of the hypothalamus and its relationship with polycystic ovary syndrome (PCOS) in rats. Materials and Methods: In the current experimental study, 24 female rats were randomly and equally allocated into nulliparous and primiparous groups and then were divided into two subgroups of PCOS and control. PCOS was induced by exposure to continuous light. Sex-related hormones were evaluated by radioimmunoassay or immunoradiometric assay. Expressions of MC4R and kiss1 gene in the ARC of the hypothalamus of the rats were evaluated by real-time PCR. Histomorphometric alterations of ovaries were compared between groups. Results: Number of tertiary follicles and their size and number of atretic follicles in the PCOS subgroups were more than those in the controls (P<0.05) whereas the number of secondary follicles and corpus luteum in the PCOS subgroups were lower than those in the controls (P<0.05). Antrum and total diameters of tertiary follicles in the PCOS subgroups were greater and granulosa layer diameter was lower than those in the controls (P<0.05). The MC4R mRNA expression in the PCOS subgroups was 6.5-fold in nulliparous and 3.5-fold in primiparous groups more than their controls’ pairs (P<0.05). However, parity did not affect the expression of MC4R gene (P>0.05). The kiss1 mRNA expression in the PCOS and control subgroups was not significantly different (P>0.05). Conclusion: Overexpression of MC4R gene after PCOS induction in the ARC of the hypothalamus may link to metabolic disorders of induced PCOS in the rats. However, alteration in the kiss1 mRNA expression after PCOS induction was not observed in the rats.

Conspecific odor exposure predominantly activates non-kisspeptin cells in the medial nucleus of the amygdala

A small neuronal subpopulation in the medial nucleus of the amygdala (MeA), expressing the Kiss1 gene, is now considered an important mediator that integrates socio-sexual behavior and odor information in order to modulate the Hypothalamic-Pituitary-Gonadal (HPG) axis. Previous studies demonstrated that exogenous kisspeptin administration or selective activation of Kiss1-expressing neurons in the MeA modulates the onset of puberty, LH secretion and sexual behavior. These functions are supported by the known MeA neuronal connections. In the MeA, as well as in the hypothalamus, Kiss1 mRNA expression mostly depends on sex steroids levels. However, the percentage of Kiss1-expressing cells that co-express estrogen receptor α (ERα) in the MeA is currently unknown. Additionally, whether MeA kisspeptin neurons show Fos expression due to pheromone exposure is still undisclosed. In the present study, we used adult male and female mice that express a reporter protein under the Kiss1 promoters to determine the percentage of Kiss1-expressing neurons that co-express the ERα in the MeA and, whether those cells are activated by olfactory cues. We found a high percentage of Kiss1-expressing neurons in the MeA co-expressing the ERα. The proportion of co-expression was similar between male and female mice in diestrus. Interestingly, a low percentage of Kiss1-expressing neurons in the MeA co-express Fos after conspecific odor exposure, despite a significant increase of Fos positive cells in the MeA. Additionally, odor exposition leads to a sexually dimorphic change in Kiss1 expression in the posterior subdivision of the MeA. Our findings suggest that olfactory signals predominantly activate non-kisspeptin cells in the MeA to modulate responses to pheromones and therefore the HPG axis.

The Effect Of Exercise Mode On The Hypothalamic Expression Of Kiss-1and Gpr54 Genes Mrna In Dietinduced Obesity Rats

Kisspeptin, a hypothalamic peptide coded by the KiSS1 gene, is a neuromodulator that controls GnRH secretion and is now recognized as a crucial regulator of the onset of puberty. PURPOSE: To explore the difference roles of moderate-intensity treadmill training (MIT) and high intensity interval treadmill training (HIIT) in modulating the hypothalamic expression of KiSS-1and the G-protein coupled receptor (GPR) 54 mRNA in the diet induced obesity male rats. METHODS: After 8 weeks high fat feeding, 24 obesity 11-weeks SD rats were randomly assigned to sedentary (FS, n=8), MIT (n=8) , and HIIT (n=8) groups, 8 normal diet 11-weeks SD rats were assigned as sedentary (SS, n=8) groups. During the following 8 weeks, obesity rats were continued expose to high-fat-diet. MITgroup did the 60%-70%V(•)O2max treadmill training (5 days/week, 1 hour/day). HIIT group did the HIIT training (5 days/week, 1 hour/day),which included 7 minutes warmup (70% V(•)O2max), 6groups formal training(90% V(•)O2max*3min+ 50% V(•)O2max*3min) and 7 minutes recobery (70% V(•)O2max) The V(•)O2 max of exercise groups were remeasured every two weeks. The hypothalamic expression of KiSS-1 and GPR54 mRNA were tested in each group. RESULTS: After the first 8-weeks high fat feeding, the obesity rats were heavier than normal diet group (491.74±26.19g vs. 410.05±45.77g, p<0.01). After 8-weeks training, FS group was still heavier than SS group (681±52.56g vs. 574.27±52.43g, p<0.01), and had more hypothalamic expression of KiSS-1 mRNA(1.51±0.66 vs 0.75±0.27, p<0.05) and GPR54 mRNA (2.45±0.38 vs 0.61±0.15, p<0.01). Both MIT and HIIT groups weighted less than FS group, HIIT group had the lightest bodyweight (590.23±35.74g, 558.1±29.57g vs 681±52.56g). Compared with FS group, although both MIT and HIIT groups had lower hypothalamic expression of KiSS-1 mRNA and GPR54 mRNA, HIIT group had the lowest hypothalamic expression of KiSS-1 mRNA (0.47±0.13 vs 0.69±0.13, p<0.01) and GPR54 mRNA(0.58±0.10 vs 0.23±0.06, p<0.01). CONCLUSIONS: Both MIT and HIIT could reduce the stimulating effect of high-fat diet induced obesity on bodywight and hypothalamic expression of KiSS-1and GPR54 mRNA, and HIIT could play a better role.

Increased kisspeptin mRNA expression derived from abnormally adhered placenta: compensatory inhibition of abnormal placental invasion?

Purpose of investigation: In normal conditions, circulating kisspeptin levels dramatically increase during the first trimester of pregnancy and fall approximately five days post-delivery to concentrations comparable to those detected prior to pregnancy. Dysregulation of trophoblast invasion results in a wide spectrum of abnormal pregnancies such as preeclampsia, premature delivery, and choriocarcinoma. The aim of the present study was to investigate the expression profile of KiSS-1 in abnormally adherent placenta specimens (placenta accreta and placenta praevia). Materials and Methods: Ten term trophoblast preparations (five normal adhesions, four placenta accretae and one placenta praevia) were obtained for RNA extraction and immunohistochemistry in order to determine KiSS-1 mRNA and protein levels. Results: KiSS-1 mRNA expression was found to be increased in conditions of pathological placental adhesion compared to normal tissues. Conclusion: KiSS-1 is implicated in the regulation of placental invasion as part of a compensatory inhibition to abnormal placental adhesion.

Analysis of the association of the expression of KiSS-1 in colorectal cancer tissues with the pathology and prognosis.

Colorectal cancer is a common malignant tumor of the digestive tract with high morbidity and mortality rates. The aim of the present study was to examine the expression level of KiSS-1 in tumor tissues of patients with colorectal cancer, and to explore the relationship with the clinicopathology and prognosis of patients with colorectal cancer. Frozen tumor tissue and corresponding cancer-adjacent normal tissue specimens were selected from 56 patients with colorectal cancer who were treated in the Department of Surgery of our hospital from May 2009 to December 2011. The expression levels of KiSS-1 messenger ribonucleic acid (mRNA) in tumor tissues and cancer-adjacent normal tissues were detected by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). The expression levels of KiSS-1 proteins in colorectal cancer tissues and cancer-adjacent normal tissues were further detected by immunohistochemistry. In addition, the association of the expression level of KiSS-1 proteins in tissues of colorectal cancer patients with pathological parameters and the prognosis of patients with colorectal cancer was analyzed combined with clinical data. The RT-qPCR results showed that the expression of KiSS-1 mRNA in colorectal cancer tissues was significantly lower than that in cancer-adjacent normal tissues (P<0.05). Immunohistochemistry results indicated that the positive expression rate of KiSS-1 proteins in colorectal cancer tissues (26.79%) was significantly lower than that in cancer-adjacent normal tissues (80.36%). The low expression of KiSS-1 in colorectal cancer tissues was associated with the degree of differentiation, invasion and metastasis, as well as clinical staging. The 5-year overall survival rate of patients with colorectal cancer was 55.36% (31/56). The univariate survival analysis showed that patients with lowly expressed KiSS-1 had worse prognosis. The low expression of KiSS-1 is closely associated with the occurrence and development of colorectal cancer, especially to the degree of differentiation, invasion and metastasis, as well as clinical staging. Thus, the expression of KiSS-1 in colorectal cancer tissues can be used as a reference for the prognosis of colorectal cancer, and KiSS-1 is a potential new target for the treatment of colorectal cancer.

The effect of neonatal immune challenge on reproduction by altering intraovarian kisspeptin/GPR54 system in the rat

Immune challenge in early life has been observed to influence the long-term reproductive dysfunction. On PNDs 3 and 5, female offsprings were administered with LPS (50μg/kg, i.p.) or saline. Vaginal opening was recorded, and oestrous cyclicity was monitored immediately post puberty and again at 56–70 days. At 10 weeks of age, the ovaries were removed for immunostaining and RNA analysis. Neonatal exposure to LPS resulted in a significant delay puberty onset as well as destroyed expression of ovulation related genes. At PND 42 and 70, a significant increase in Kiss1 mRNA and Kisspeptin expression was detected at proestrus and oestrus in neo-LPS treated rats compared with the counterparts. Therefore, neonatal LPS exposure had a long-term effect on reproductive function and the up-regulated expression of ovarian Kiss1 and kisspeptin during the ovulatory transition stage may contribute to ovulatory dysfunction induced by peripheral LPS administration in early life.

Role of amygdala kisspeptin in pubertal timing in female rats.

To investigate the mechanism by which maternal obesity disrupts reproductive function in offspring, we examined Kiss1 expression in the hypothalamic arcuate (ARC) and anteroventral periventricular (AVPV) nuclei, and posterodorsal medial amygdala (MePD) of pre-pubertal and young adult offspring. Sprague-Dawley rats were fed either a standard or energy-dense diet for six weeks prior to mating and throughout pregnancy and lactation. Male and female offspring were weaned onto normal diet on postnatal day (pnd) 21. Brains were collected on pnd 30 or 100 for qRT-PCR to determine Kiss1 mRNA levels. Maternal obesity increased Kiss1 mRNA expression in the MePD of pre-pubertal male and female offspring, whereas Kiss1 expression was not affected in the ARC or AVPV at this age. Maternal obesity reduced Kiss1 expression in all three brain regions of 3 month old female offspring, but only in MePD of males. The role of MePD kisspeptin on puberty, estrous cyclicity and preovulatory LH surges was assessed directly in a separate group of post-weanling and young adult female rats exposed to a normal diet throughout their life course. Bilateral intra-MePD cannulae connected to osmotic mini-pumps for delivery of kisspeptin receptor antagonist (Peptide 234 for 14 days) were chronically implanted on pnd 21 or 100. Antagonism of MePD kisspeptin delayed puberty onset, disrupted estrous cyclicity and reduced the incidence of LH surges. These data show that the MePD plays a key role in pubertal timing and ovulation and that maternal obesity may act via amygdala kisspeptin signaling to influence reproductive function in the offspring.

GLP-1 increases Kiss-1 mRNA expression in kisspeptin-expressing neuronal cells.

Feeding-related metabolic factors exert regulatory influences on the hypothalamic-pituitary-gonadal axis. Glucagon-like peptide-1 (GLP-1) is an anorexigenic hormone synthesized from the ileum in response to food intake. The purpose of this study was to examine the direct effect of GLP-1 on hypothalamic kisspeptin and gonadotropin-releasing hormone (GnRH) expression using the rat clonal hypothalamic cell line rHypoE-8. GLP-1 significantly increased Kiss-1 mRNA expression in rHypoE-8 cells up to 1.94 ± 0.22-fold. This effect of GLP-1 on Kiss-1 gene expression was also observed in GT1-7 GnRH-producing neurons and in primary cultures of fetal rat brain. GLP-1 increased cAMP-mediated signaling, as determined by cAMP response element activity assays, but failed to activate extracellular signal-regulated kinase pathways. Another anorexigenic factor, leptin, similarly increased Kiss-1 mRNA levels up to 1.34 ± 0.08-fold in rHypoE-8 cells. However, combined treatment with GLP-1 and leptin failed to potentiate their individual effects on Kiss-1 mRNA expression. Gnrh mRNA expression was not significantly increased by GLP-1 stimulation in rHypoE-8, but kisspeptin significantly stimulated the expression of Gnrh mRNA in these cells. Our current observations suggest that the anorexigenic peptide GLP-1 directly regulates Kiss-1 mRNA expression in these hypothalamic cell lines and in neuronal cells of fetal rat brain and affects the expression of Gnrh mRNA.

Participation of hypothalamic CB1 receptors in reproductive axis disruption during immune challenge.

Immune challenge inhibits reproductive function and endocannabinoids (eCB) modulate sexual hormones. However, no studies have been performed to assess whether the eCB system mediates the inhibition of hormones that control reproduction as a result of immune system activation during systemic infections. For that reason, we evaluated the participation of the hypothalamic cannabinoid receptor CB1 on the hypothalamic-pituitary-gonadal (HPG) axis activity in rats submitted to immune challenge. Male adult rats were treated i.c.v. administration with a CB1 antagonist/inverse agonist (AM251) (500ng/5 μL), followed by an i.p. injection of lipopolysaccharide (LPS) (5mg/kg) 15minutes later. Plasmatic, hypothalamic and adenohypophyseal pro-inflammatory cytokines, hormones and neuropeptides were assessed 90 or 180minutes post-LPS. The plasma concentration of tumour necrosis factor α and adenohypophyseal mRNA expression of Tnfα and Il1β increased 90 and 180minutes post i.p. administration of LPS. However, cytokine mRNA expression in the hypothalamus increased only 180minutes post-LPS, suggesting an inflammatory delay in this organ. CB1 receptor blockade with AM251 increased LPS inflammatory effects, particularly in the hypothalamus. LPS also inhibited the HPG axis by decreasing gonadotrophin-releasing hormone hypothalamic content and plasma levels of luteinising hormone and testosterone. These disruptor effects were accompanied by decreased hypothalamic Kiss1 mRNA expression and prostaglandin E2 content, as well as by increased gonadotrophin-inhibitory hormone (Rfrp3) mRNA expression. All these disruptive effects were prevented by the presence of AM251. In summary, our results suggest that, in male rats, eCB mediate immune challenge-inhibitory effects on reproductive axis at least partially via hypothalamic CB1 activation. In addition, this receptor also participates in homeostasis recovery by modulating the inflammatory process taking place after LPS administration.

The expression and significance of Kiss1 protein in colon adenoma and colon carcinoma

Objective To investigate the expression and significance of Kiss1 protein in colon adenoma and colon carcinoma. Methods Immunohistochemistry and real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) were used to detect the location and expression of Kiss1 in the 20 normal colon mucosae, 30 colon carcinomae, 80 colon adenomae. Results The positive expression rate of Kiss1 protein in normal colorectal mucosa, colorectal adenoma and colorectal carcinoma tissues was 93.3%, 58.8% and 5.0% respectively, with significant differences among them (P=0.005). The positive expression rate of Kiss1 protein in tubular adenoma, mixed pattern of adenoma and villous adenoma was 80.0%, 66.7% and 35.0% respectively, with significant differences among them (P=0.005). FQ-PCR showed that the Kiss1 mRNA expression rate was 28.85±8.34, 14.61±1.65, 7.58±1.31, 2.26±1.56 and 0.50±0.40 in normal colorectal mucosa, tubular adenoma, mixed pattern of adenoma, villous adenoma and colorectal carcinoma, respectively. Conclusion Kiss1 is correlated with canceration of colorectal adenoma and the development of colorectal carcinoma. Detecting the expression of Kiss1 can evaluate the progression of colorectal adenoma and the development of colorectal carcinoma. Key words: Colorectal adenoma; Colorectal carcinoma; Kiss1