Effects Of Kisspeptin Research Articles

Kisspeptin-10 in cryodiluent improves the post-thaw quality of Nili-Ravi buffalo (Bubalus bubalis) bull spermatozoa.

Effects of kisspeptin-10 as antioxidant in cryodiluent were evaluated on post-thaw quality of buffalo spermatozoa. Qualified semen samples from five bulls were pooled, divided into five aliquots and extended in Tris-citric acid cryodiluent containing differential doses of kisspeptin-10 (5, 10, 15, and 20 μmol L-1 and negative control. Extended sperm suspension was cooled to 4°C, packaged in 0.54 ml straws and cryopreserved. At post-thawing, catalase (unit mg-1 ), peroxidase (unit mg-1 ) and reduced glutathione (μmol L-1 ) levels were highest (p < 0.05) with 20 μmol L-1 of kisspeptin-10 as compared to negative control. Moreover, lipid peroxidation (nmol L-1 min-1 mg protein-1 ) level was lowest (p < 0.05) with 20 μmol L-1 of kisspeptin-10. Sperm progressive motility (%), rapid velocity (%) and kinematics were higher (p < 0.05) with 15 and 20 μmol L-1 of kisspeptin-10 as compared to negative control. Supra-vital plasma membrane integrity (%), viable sperm with intact acrosome (%) and DNA integrity (%) were improved (p < 0.05) with all doses of kisspeptin-10 as compared to negative control. It was concluded that the addition of 15 and 20 μmol L-1 kisspeptin-10 in cryodiluent ameliorated the overall frozen-thawed quality parameters of Nili-Ravi buffalo spermatozoa.

Effects of kisspeptin-10 on the reproductive performance of sows in a fixed-time artificial insemination programme

Kisspeptin (KP) is a major positive regulator of the hypothalamo–pituitary–gonadal axis and affects female reproductive cyclicity in mammals. It offers an attractive alternative strategy to control reproduction in fixed-time artificial insemination (FTAI) protocols. We aimed to evaluate the effects of different doses of kisspeptin-10 (KP-10) on sow reproductive performance in FTAI protocols. One hundred ninety-eight weaned sows were divided into three groups at random. A FTAI–GnRH group of sows (n = 98) received 100 µg (2 mL) gonadotropin-releasing hormone (GnRH; gonadorelin) by intramuscular injection at 96 h after weaning (t = 0 h); FTAI–KPL (KPL: low-dose KP-10, n = 50), and FTAI–KPH groups of sows (KPH: high-dose KP-10, n = 50) received 0.5 or 1 mg KP-10 (2 mL) respectively at 96 h after weaning. Sows were checked twice daily for oestrus. Ultrasonographic evaluations were performed to determine the follicular diameter and time of ovulation; blood samples were collected immediately before injection (t0 = 0 min) and at 15, 30, 45, 60, 75, 90 min, 24 and 48 h postinjection. Sows were inseminated at 112 and 132 h after weaning. The oestrus rates (96 vs 92%; 96 vs 88%) and weaning-to-oestrus intervals (98.9 vs 98.6 h; 98.9 vs 97.1 h) were not affected by treatment, but oestrus in the FTAI–KPL group was significantly longer than in the FTAI–GnRH group (38.7 vs 30.0 h; P < 0.05). The peak LH concentrations were 1.29 times greater than at t0 = 0 in the FTAI–GnRH group, and 1.45 and 1.44 times greater than at t0 = 0 in the FTAI–KPL and FTAI–KPH groups, respectively. Follicular diameters and pregnancy rates (86 vs 88%, 86 vs 80%, respectively) did not differ between the treatments. Moreover, the total numbers of piglets born and those born alive did not differ among the three groups. These findings suggested that 0.5 mg KP-10 given at 96 h after weaning could be used in FTAI programmes to manage batch farrowing in sows.

Conditioned place preference of kisspeptin-10

INTRODUCTION: Kisspeptins (KISS), a group of brain neuropeptides are involved in sexual behavior. KISS activate the hypothalamic neurons that synthesize gonadotropin releasing hormone. KISS was also detected in the limbic system. Earlier, we showed the activation of sexual motivation after the administration of kisspeptin-10 without increasing the level of testosterone in male rats, which suggests the extrahypothalamic effect of KISS.&#x0D; The aim of this work was to study the possibility of aquisition of conditioned place preference of kisspeptin-10, as well as to study the emotional and investigational behavior in rats after intranasal peptide administration.&#x0D; METHODS: Conditioned place preference test (CPP), open field test (OP) and elevated plus maze (EPM) were used in male Wistar rats.&#x0D; RESULTS: When studying CPP, animals spent 78.6 6.3% of the time in the chamber associated with the administration of KISS compared to control animals with administration of physiological saline (51.2% of the experiment time; p 0.05). After kisspeptin-10 administration locomotor activity was 2-fold increased (p 0.05), and the number of sniffings was 2-fold increased too (p 0.05). The parameters did not significantly differ in animals treated with kisspeptin or saline in PCL.&#x0D; CONCLUSION: Thus repeated intranasal administration of kisspeptin-10 induces the aquisition of CPP in rats. This suggests that kisspeptin-10 can cause activity in the reward system or the activation of brain regions associated with this system, which ultimately leads to the formation of an emotionally positive state.

Investigation of the effects of kisspeptin-10 in methionine-induced lipid peroxidation in testicle tissue of young rats.

Disruption of the balance oxidants, antioxidants cause various pathophysiological conditions such as lipid peroxidation, protein degradation, or DNA damage. We have examined possible effects of kisspeptin-10 on the structural damage produced by methionine-induced lipid peroxidation in testicle tissue of young rats. Kisspeptin-10 did not significantly affect spermatogenic cells in seminiferous tubules. Testosterone levels decreased in the methionine group as compared with the control group but without statistical significance. Luteinizing hormone levels decreased in the methionine group as compared with the control group (P<0.001). Catalase enzyme activity increased in the kisspeptin-10 group (P<0.01) as compared with the other groups. Catalase mRNA expression was decreased in the methionine group as compared with the kisspeptin group (P<0.001). Total superoxide dismutase enzyme activity and superoxide dismutase mRNA expression were increased in the kisspeptin group as compared with the methionine group (P<0.05). In conclusion, kisspeptin treatment may protect the structure of spermatogenic cells against methionine-induced damage.

Abstract 17078: A Potent Vasoconstrictor Kisspeptin-10 Induces Atherosclerotic Plaque Progression and Instability

Background: Recently, there is a great deal of research interest regarding the role and effects of kisspeptin-10 (KP-10), a potent vasoconstrictor and inhibitor of angiogenesis expressed in vascular endothelial cells (ECs), in cardiovascular disease. However, it still remains unknown whether KP-10 could affect atherogenesis. Objective and Methods: We aimed to clarify the effects of KP-10 on atherosclerosis. We evaluated the effects of KP-10 on human umbilical vein endothelial cells (HUVECs), human monocyte-derived macrophages, human aortic smooth muscle cells (HASMCs) in vitro , and aortic lesions in ApoE -/- mice in vivo . Results: GPR54, a KP-10 receptor, was expressed at higher levels in human monocytes, macrophages, HASMCs, and HUVECs. KP-10 significantly suppressed the proliferation of EAhy.926 ECs. KP-10 significantly increased the adhesion of THP1 monocytes to HUVECs associated with increased endothelial expressions of IL-6, MCP-1, TNF-α, ICAM-1, VCAM-1, and E-selectin. KP-10 significantly enhanced oxidized low-density lipoprotein-induced foam cell formation associated with increased expressions of CD36 and acyl-CoA:cholesterol acyltransferase-1 in human monocyte-derived macrophages. KP-10 significantly suppressed the migration and proliferation of HASMCs with inducing apoptosis via AKT, p38, and bax upregulation, but significantly enhanced the activities of MMP-2 and MMP-9 in HASMCs. Four-week-infusion of KP-10 into ApoE -/- mice significantly accelerated the development of aortic atherosclerotic lesions with increased monocyte/macrophage infiltration. Conclusions: Our results indicate that KP-10 accelerates atherogenesis by enhancing EC inflammatory responses and macrophage foam cell formation, In addition, KP-10 suppresses EC proliferation, VSMC migration and proliferation, but enhances MMP-2 and MMP-9 activities in VSMCs, which may contribute to plaque instability, leading to plaque rupture. Thus, KP-10 may serve as a novel therapeutic target for acute coronary syndrome.

Effects of kisspeptin-10 on in vitro proliferation and kisspeptin receptor expression in primary epithelial cell cultures isolated from bovine placental cotyledons of fetuses at the first trimester of pregnancy

Kisspeptin (Kp) and Kiss-1 receptor (Kiss-1R) expressions have been reported to be in the placenta, and a possible involvement of the Kiss-1R/Kps system in regulating trophoblast invasion and proliferation has been hypothesized. The aim of the present study was to investigate whether Kiss-1R activation by kisspeptin-10 (Kp-10) could modulate in vitro proliferation and progesterone (P4) secretion of bovine primary placental cell lines isolated from cotyledons of fetuses in the first trimester of pregnancy. The involvement of Kiss-1R in the cell responses observed was also analyzed. Uteri from cows at the first trimester of pregnancy were obtained from local abattoirs. Fetal cotyledon fragments were digested with collagenase in low glucose Dulbecco's Modified Eagle's Medium and cell lines were isolated. After being characterized for epithelial polygonal morphology, the presence of binucleate cells, male gender, and the expression of cytokeratin and zona occludens 2, cell lines were cultured in a low glucose Dulbecco's Modified Eagle's Medium–based expansion medium in the presence of 0.01, 0.1, 1, and 10 μM Kp-10. Control cells were cultured in the absence of Kp-10. Cell population doubling time was evaluated for each culture passage (P) from P1 to P10. Cells were tested for Kiss-1R mRNA expression analysis by real-time reverse transcription–polymerase chain reaction, and culture media were analyzed for P4 concentration by radioimmunoassay. Kisspeptin-10 modulated in vitro proliferation of epithelial cell lines isolated from cotyledons recovered from bovine fetuses in the first trimester of pregnancy. Inhibitory (line A) or stimulatory (line B) effects of Kp-10 on cell proliferation were found in different cell lines and observed cell responses were found to be related to Kiss-1R mRNA levels. Inhibition of cell proliferation matched with not significant variation of Kiss-1R expression, whereas stimulation of cell proliferation was found to be related to Kiss-1R upregulation. In both cell lines, no effect of Kp-10 on P4 secretion was found at any tested concentration. These results lead to the conclusion that the Kiss-1R/Kps system is involved in the regulation of cell proliferation of bovine placental cotyledon cell lines isolated at the first trimester of pregnancy but, at this gestational stage, it may not be involved in modulating placental P4 secretion.

Effects of kisspeptin-10 on lipid metabolism in cultured chicken hepatocytes.

Our previous studies showed that kisspeptin-10 (Kp-10) injected in vivo can markedly increase lipid anabolism in liver of quails. In order to investigate the direct effect of Kp-10 on lipid metabolism of hepatocytes in birds, cells were separated from embryos livers and cultured in vitro with 0, 100 and 1,000 nM Kp-10, respectively. The results showed that after 24 h treatment, cells viability was not affected by 100 nM Kp-10, but showed a mild decrease with 1,000 nM Kp-10 compared to the control cells. Based on the results of the cell viability, 100 nM dosage of Kp-10 was selected for the further study and analysis. Compared with control cells, total cholesterol (Tch) contents in 100 nM treated cells were increased by 51.23%, but did not reach statistical significance, while the level of triglyceride (TG), high density of lipoprotein-cholesterol (HDL-C) and low density of lipoprotein-cholesterol (LDL-C) were significantly increased. Real-time PCR results showed that ApoVLDL-II mRNA expression had a tendency to increase, genes including sterol regulatory element-binding protein-1 (SREBP-1), acetyl coenzyme A carboxylase α (ACCα), carnitine palmitoyltransferase 1 (CPT1), 3-hydroxyl-3-methylglutaryl-coenzyme A reductases (HMGCR) and stearyl coenzyme A dehydrogenase-1 (SCD1) mRNA in hepatocytes were significantly down-regulated by 100 nM Kp-10. However, contrary to its gene expression, SREBP-1 protein expression was significantly up-regulated by 100 nM Kp-10. Some of the significant correlations in mRNA expression were found between genes encoding hepatic factors or enzymes involved in lipid metabolism in liver of birds. These results indicate that Kp-10 stimulates lipid synthesis directly in primary cultured hepatocytes of chickens.

Effects of kisspeptin-10 on progesterone secretion in cultured chicken ovarian granulosa cells from preovulatory (F1–F3) follicles

The effect of kisspeptin-10 (Kp-10) on the secretion of progesterone (P4) was investigated in cultured granulosa cells from F1 to F3 follicles of hens. The results showed that granulosa cells were stained with clear signals for kisspeptin using immunocytochemistry with the specific antibody against Kp-10. Among 10, 100 and 1000nM concentrations tested, 100nM Kp-10 treated for 24h significantly increased P4 secretion in granulosa cells from F1 to F3 follicles. After 24h and 48h of treatment, 100nM Kp-10 showed a significant increase in P4 secretion, while after 72h of treatment P4 secretion was markedly decreased by Kp-10 compared to the control group (P<0.05). F1 and F2/3 cells treated with 100nM Kp-10 for 24h showed significantly increased viability (P<0.05) and which was in parallel to a marked increase in P4 secretion (P<0.01). Real-time PCR results showed that the gene expression of the steroidogenic acute regulatory protein (StAR), cytochrome P450 side-chain cleavage (P450scc) and the enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD) in F1 and F2/3 granulosa cells was significantly up-regulated by 24h–100nM Kp-10 treatment (P<0.05 versus P<0.01, respectively). However, there was no significant difference in StAR, P450scc and 3β-HSD protein content between control and the Kp-10 treated group (P>0.05). These results indicate that Kp-10 stimulates P4 secretion in cultured chicken granulosa cells, which was associated with an up-regulation in StAR, P450scc and 3β-HSD gene transcription.

Ontogeny and mechanisms of action for the stimulatory effect of kisspeptin on gonadotropin-releasing hormone system of the rat

Kisspeptins have recently emerged as essential regulators of gonadotropin secretion and puberty onset. These functions are primarily conducted by stimulation of hypothalamic gonadotropin-releasing hormone (GnRH) secretion. However, relevant aspects of KiSS-1 physiology, including the ontogeny and major signaling systems of its stimulatory action, remain to be fully elucidated. To cover these issues, the effects of kisspeptin-10 on GnRH and LH secretion were monitored at early stages of postnatal maturation, and potential changes in the sensitivity to kisspeptin were assessed along the pubertal transition in the rat. In addition, the signaling cascades involved in kisspeptin-induced GnRH secretion were explored by means of pharmacological blockade using rat hypothalamic explants. Despite sexual immaturity, kisspeptin-10 potently elicited GnRH release ex vivo and LH secretion in vivo at early stages (neonatal to juvenile) of postnatal development. Yet, LH responsiveness to low doses of kisspeptin was enhanced in peri-pubertal animals. Concerning GnRH secretion, the stimulatory action of kisspeptin-10 required activation of phospholipase-C, mobilization of intracellular Ca 2+ and recruitment of ERK1/2 and p38 kinases, but was preserved after blockade of type 2 cyclo-oxygenase and prostaglandin synthesis. In summary, our present data document the ontogeny, sensitivity and intracellular signals for the stimulatory action of kisspeptin on the GnRH/LH axis in the rat. Although LH responses to low doses of kisspeptin appeared to be enhanced at puberty, kisspeptin was able to readily activate the GnRH system at early stages of postnatal maturation. These observations further stress the essential role of kisspeptin in normal, and eventually pathological, timing of puberty.