Characterization of the dynamic change of microRNA expression in mice hypothalamus during the time of female puberty

Gideon Omariba,Li Tong,Maochun Wang,Kai Li,Yuxun Zhou,Junhua Xiao 한국유전학회 2018 Genes & Genomics Vol.40 No.3

Puberty onset is a milestone in sexual development. A tumor suppress gene (TSG) network had been reported to be involved in the regulation of female puberty onset. The observations in rodents and primates showed a potential link between microRNAs and puberty onset. To figure out what miRNAs play roles in this important biological process, profilings of microRNAs in the hypothalamus of female mice from three different pubertal stages, juvenile [postnatal day (P10)], early pubertal (P25) and pubertal (P30) were performed on the Affymetrix GeneChip miRNA 3.0 Arrays, the cerebral cortex (CTX) was used as a control tissue. 20 miRNAs were shown to be differentially expressed in hypothalamus (fold change > 1.5, P < 0.05), but not in CTX during the transition from juvenile to pubertal. Four of them were validated by real-time quantitative RT-PCR (qRTPCR) method. 1018 genes were predicted as the targets of these miRNAs. Further bioinformatics analysis suggested that these target genes were involved in many important signaling pathways, especially in the cancer related pathways. We also found that about 90% of these target genes were expressed in the hypothalamus, as well as in the immortalized GnRH-producing GT1-7 cells, which provided additional evidence that these miRNAs could be female puberty onset related. Here we present a novel comprehensive data set of miRNA gene expression during the puberty onset; and it provides an important recourse for the future functional characterization of individual miRNAs and their targets in mouse hypothalamus and in GT1-7 cells.

Advanced Onset of Puberty in High-Fat Diet-fed Immature Female Rats - Activation of KiSS-1 and GnRH Expression in the Hypothalamus -

이송이,장연석,이용현,서향희,노금희,이성호 한국발생생물학회 2009 발생과 생식 Vol.13 No.3

In mammals, puberty is a dynamic transition process from infertile immature state to fertile adult state. The neuroendocrine aspect of puberty is started with functional activation of hypothalamus-pituitary-gonadal hormone axis. The timing of puberty can be altered by many factors including hormones and/or hormone-like materials, social cues and metabolic signals. For a long time, attainment of a particular body weight or percentage of body fat has been thought as crucial determinant of puberty onset. However, the precise effect of high-fat (HF) diet on the regulation of hypothalamic GnRH neuron during prepubertal period has not been fully elucidated yet. The present study was undertaken to test the effect of a HF diet on the puberty onset and hypothalamic gene expressions in immature female rats. The HF diet (45% energy from fat, HF group) was applied to female rats from weaning to around puberty onset (postnatal days, PND 22-40). Body weight and vaginal opening (VO) were checked daily during the entire feeding period. In the second experiment, all animals were sacrificed on PND 36 to measure the weights of reproductive tissues. Histological studies were performed to assess the effect of HF diet feeding on the structural alterations in the reproductive tissues. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Body weights of HF group animals tend to be higher than those of control animals between PND 22 and PND 31, and significant differences were observed PND 32, PND 34, PND 35 and PND 36 (p<0.05). Advanced VO was shown in the HF group (PND 32.8±0.37 p<0.001) compared to the control (PND 38.25±0.25). The weight of ovaries (p<0.01) and uteri (p<0.05) from HF group animals significantly increased when compared to those from control animals. Corpora lutea were observed in the ovaries from the HF group animals but not in control ovaries. Similarly, hypertrophy of luminal and glandular uterine epithelia was found only in the HF group animals. In the semi-quantitative RT-PCR studies, the transcriptional activities of KiSS-1 in HF group animals were significantly higher than those from the control animals (p<0.001). Likewise, the mRNA levels of GnRH (p<0.05) were significantly elevated in HF group animals. The present study indicated that the feeding HF diet during the post-weaning period activates the upstream modulators of gonadotropin such as GnRH and KiSS-1 in hypothalamus, resulting early onset of puberty in immature female rats.

Advanced Onset of Puberty in High-Fat Diet-Fed Immature Female Rats : Activation of KiSS-1 and GnRH Expression in the Hypothalamus

Lee Song-Yi,Jang Yeon-Seok,Lee Yong-Hyun,Seo Hyang-Hee,Noh Kum-Hee,Lee Sung-Ho 한국발생생물학회 2009 발생과 생식 Vol.13 No.3

In mammals, puberty is a dynamic transition process from infertile immature state to fertile adult state. The neuroendocrine aspect of puberty is started with functional activation of hypothalamus-pituitary-gonadal hormone axis. The timing of puberty can be altered by many factors including hormones and/or hormone-like materials, social cues and metabolic signals. For a long time, attainment of a particular body weight or percentage of body fat has been thought as crucial determinant of puberty onset. However, the precise effect of high-fat (HF) diet on the regulation of hypothalamic GnRH neuron during prepubertal period has not been fully elucidated yet. The present study was undertaken to test the effect of a HF diet on the puberty onset and hypothalamic gene expressions in immature female rats. The HF diet (45% energy from fat, HF group) was applied to female rats from weaning to around puberty onset (postnatal days, PND 22-40). Body weight and vaginal opening (VO) were checked daily during the entire feeding period. In the second experiment, all animals were sacrificed on PND 36 to measure the weights of reproductive tissues. Histological studies were performed to assess the effect of HF diet feeding on the structural alterations in the reproductive tissues. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Body weights of HF group animals tend to be higher than those of control animals between PND 22 and PND 31, and significant differences were observed PND 32, PND 34, PND 35 and PND 36 (p<0.05). Advanced VO was shown in the HF group (PND p<0.001) compared to the control (PND ). The weight of ovaries (p<0.01) and uteri (p<0.05) from HF group animals significantly increased when compared to those from control animals. Corpora lutea were observed in the ovaries from the HF group animals but not in control ovaries. Similarly, hypertrophy of luminal and glandular uterine epithelia was found only in the HF group animals. In the semi-quantitative RT-PCR studies, the transcriptional activities of KiSS-1 in HF group animals were significantly higher than those from the control animals (p<0.001). Likewise, the mRNA levels of GnRH (p<0.05) were significantly elevated in HF group animals. The present study indicated that the feeding HF diet during the post-weaning period activates the upstream modulators of gonadotropin such as GnRH and KiSS-1 in hypothalamus, resulting early onset of puberty in immature female rats.

Effect of melatonin on the onset of puberty in male juvenile rats

Satya Prasad Venugopal,Satya Prasad Venugopal 대한해부학회 2019 Anatomy & Cell Biology Vol.52 No.3

Melatonin or N-acetyl-5-methoxytryptamine, the fascinating molecule secreted by the pineal gland. Melatonin has a close interaction with hypothalamic-pituitary-gonadal axis. In non-seasonal breeders like rat its exact role in reproduction is controvertible. So it is worth to explore the possible role of melatonin on the onset of puberty in male albino rats. Two groups of male rats aged 5 and 10 days were used for the study. In each group, there were three subgroups, each receiving melatonin for 5 days, 10 days or till the day of descent of testes. Similar subgroups were used as controls. Without handling, animals were observed daily for the onset of puberty. On the day of descent of testes, body weight of the animal was noted, blood was collected, serum was separated and used for radio immunoassay. For histomorphometric analysis, all morphometric measurements were done using an occular micrometer. Volume fraction of seminiferous tubules, intertubular connective tissue of testes, cortex and medulla of thymus were estimated by point count method. In both the age groups melatonin advanced the age on descent of testes, increased the body weight, organ weight. It also increased the serum hormone levels. So, in conclusion this study indicates that exogenous melatonin advances the onset of puberty in male albino wistar rats and this effect is more pronounced in the younger animals.

Effect of Lipopolysaccharide (LPS) Exposure on the Reproductive Organs of Immature Female Rats

Da Kyung Yoo,Sung-Ho Lee 한국발생생물학회 2016 발생과 생식 Vol.20 No.2

Lipopolysaccharide (LPS), an endotoxin, elicits strong immune responses in mammals. Several lines of evidence demonstrate that LPS challenge profoundly affects female reproductive function. For example, LPS exposure affects steroidogenesis and folliculogenesis, resulting in delayed puberty onset. The present study was conducted to clarify the mechanism underlying the adverse effect of LPS on the delayed puberty in female rats. LPS was daily injected for 5 days (50 μg/kg, PND 25-29) to treated animals and the date at VO was evaluated through daily visual examination. At PND 39, animals were sacrificed, and the tissues were immediately removed and weighed. Among the reproductive organs, the weights of the ovaries and oviduct from LPS-treated animals were significantly lower than those of control animals. There were no changes in the weights of uterus and vagina between the LPS-treated and their control animals. Immunological challenge by LPS delayed VO. Multiple corpora lutea were found in the control ovaries, indicating ovulations were occurred. However, none of corpus luteum was present in the LPS-treated ovary. The transcription level of steroidogenic acute regulatory protein (StAR), CYP11A1, CYP17A1 and CYP19 were significantly increased by LPS treatment. On the other hand, the levels of 3β-HSD, 17β-HSD and LH receptor were not changed by LPS challenge. In conclusion, the present study demonstrated that the repeated LPS exposure during the prepubertal period could induce multiple alterations in the steroidogenic machinery in ovary, and in turn, delayed puberty onset. The prepubertal LPS challenge model used in our study is useful to understand the reciprocal regulation of immune (stress) - reproductive function in early life.

KiSS-1 : A Novel Neuropeptide in Mammalian Reproductive System

이성호,최돈찬 한국발생생물학회 2005 발생과 생식 Vol.9 No.1

시상하부-뇌하수체-생식소(HPG) 호르몬 축은 유아기와 아동기에는 작동하지 않다가 사춘기 개시 직전에 활성화되는 흥분성 및 억제성 신호들의 복잡한 중추성 조절 네트워크에 의해 조절된다. 최근 주목받고 있는 kisspeptin은 KiSS-1 유전자의 펩타이드 산물로, 최초 orphan receptor로 클로닝된 G protein-coupled receptor 54(GPR54)의 내인성 리간드이다. KiSS-l은 본래 종양전이억제 유전자로 알려졌으나, 최근 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.

미성숙 암컷 흰쥐의 성 성숙에 미치는 genistein의 효과

이우철,이성호,안련섭,박미정 대한소아청소년과학회 2009 Clinical and Experimental Pediatrics (CEP) Vol.52 No.1

Puopose : Exposure to dietary phytoestrogens such as genistein during early childhood is a growing public health concern. We examined the effect of early exposure to genistein on sexual maturation in immature rats. Methods : Weaning (3wk-old) Sprague-Dawley female rats were assigned to three groups (n=6 for each): fed by high dose of genistein (100 mg/kg/d), low dose of genistein (10 mg/kg/d) and control group. First vaginal opening (VO) day was observed. Structural alterations in the ovary and uterus were assessed by histologically. Expression of genes of ERα, ERβ, and progesterone receptor (PR) in the ovary and uterus were investigated by RT-PCR. Results : High genistein group had earlier VO than control and low genistein group. Graafian follicles and corpora lutea were observed from the ovary of genistein-treated groups, while primary, secondary follicles and small atretic follicles were observed in the control group. Hypertrophy of luminal and glandular uterine epithelia were found in the genistein-treated groups while poor development of gland and fewer myometrial cell layers were evident in control group. In ovary, the transcriptional activities of ERα and ERβ were higher in high genistein group than in controls. In uterus, the transcriptional activities of ERα, ERβ and PR were higher in low genistein group than in controls. Conclusion : Acute exposure to genistein during the prepubertal period could activate the reproductive endocrine system resulting in the early onset of puberty in female rats. Further clinical investigation on the effect of genistein on the sexual maturation in children is warranted. 목 적 : 어린시기에 genistein과 같은 식물성 에스트로겐의 섭취가 사회적 관심사로 대두되고 있다. 본 연구에서는 어린 쥐에서 genistein에 노출이 사춘기 개시 및 생식기관에 미치는 영향을 알아 보았다. 방 법 : 이유기(3주령) 암컷 흰쥐를 저용량 genistein (10 mg/ kg/day), 고용량 genistein (100 mg/kg/day), 대조군의 세 그룹 (각 그룹 당 n=6)으로 나누고 첫 번째 질구 개방이 확인되는 날까지 농도별로 각각 경구 투여하였다. 질구 개방일을 확인하고 생식 기관의 무게를 측정하며 난소와 자궁에서 ERα, ERβ, PR 유전자들의 발현양상을 RT-PCR을 이용해 비교하였고, 난소와 자궁의 구조적 이상을 확인하기 위해 조직학적 분석을 실시하였다. 결 과 : 고용량 genistein 투여군은 저용량군 및 대조군에 비해 질구 개방일이 유의하게 촉진되었다. RT-PCR결과, ERα, ERβ, PR의 전사활성은 genistein에 노출된 쥐들의 난소와 자궁에서 유의하게 증가하였다. 그라프 난포와 황체는 genistein 투여군의 난소에서만 발견되었고, 대조군의 난소에서는 1차, 2차 난포들과 작은 미성숙 난포들만이 관찰되었다. Genistein 처리군의 자궁에서도 내막층 근막층 및 상피층이 과다성장상태였으나 대조군에서는 모든 세포층과 분비선이 미약하게 발달하였다. 결 론 : 결론적으로, 사춘기 이전 시기에 비교적 단기간의 genistein 노출이라도 미성숙 암컷 흰쥐에서 생식 내분비 활성을 일으켜 조기 사춘기와 성 스테로이드 호르몬 수용체의 발현 양상 변화를 초래할 수 있으며, genistein의 노출이 아동기 성성숙에 미치는 영향에 대한 더욱 많은 연구가 필요할 것으로 사료된다.

An Explanation of Effect of Age Difference in Second Language Acquisition

이영수 한국영어학회 2004 영어학 Vol.4 No.4

This paper has explained the age effect on second language learners' pronunciation. By suggesting a perspective in interpreting the L2 learners' ultimate attainment in pronunciation by age differences within the framework of a biologically critical period in SLA, this paper has tried to defend the "Maturational Constraints Hypothesis." The paper has, on the basis of a critical period, discussed the CPH-supporting evidence and the counter- evidence to the CPH. The CPH is not able to account for the latter evidence. Biologically-based on the critical period, this paper suggests the maturational constraints hypothesis, which plausibly seems to compensate the CPH for its imperfect explanation for exceptionally advanced adult learners' ultimate attainment in L2 pronunciation and, at the same time, acknowledge the function of the critical period. In the "maturational vs. non-maturational constraints" framework of the hypothesis, the ultimate attainment by age differences in L2 pronunciation is explained.

Effect of Di(2-ethyl hexyl)phthalate(DEHP) on the Onset of Puberty in Female Rat

이경엽,이성호 한국발생생물학회 2006 발생과 생식 Vol.10 No.2

전세계적으로 매년 대량생산되는 프탈레이트(phthalate)류 물질은 플라스틱처럼 다양한 생활용품의 원료로 사용되기 때문에 인간에 대한 노출 정도가 매우 높은 산업 물질이다. 대표적으로 di(2-ethyl hexyl)phthalate(DEHP)와 그 활성 대사물인 monoethyl hexyl phthalate(MEHP)가 내분비계 장애물질(endocrine disruptor)로 작용하여 인간과 실험 동물의 생식계를 교란한다는 증거들이 급속히 축적되고 있 Phthalates such as di(2-ethyl hexyl)phthalate(DEHP) are industrial chemicals with wide-ranging human exposures because of their use in plastics and other common consumer products. Consequently, their adverse effects as endocrine disruptor in the reproductive physiology of both laboratory rodents and human have been studied extensively. The present study was undertaken to examine whether prepubertal exposure to DEHP affects on the onset of puberty and the associated reproductive parameters such as hormone receptor expressions in female rats. DEHP(100mg/kg/day) was administered daily from postnatal day 25(PND 25) through the day when the first vaginal opening(VO) was observed, and the animals were sacrificed on the next day. Gross anatomy and weight of reproductive tissues were compared to test the DEHP's effects on the cell proliferation. Furthermore, histological studies were performed to assess the structural alterations in the tissues. Specific radioimmunoassay was carried out to measure serum LH levels. To determine the transcriptional changes in progesterone receptor(PR), total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction(RT-PCR). As a result, delayed VO was shown in the DEHP group(PND ) compared to the control group(PND ; p<0.05). DEHP treatment significantly decreased the wet weight of ovaries and uteri compared to the control group(p<0.05). Interestingly, elevation of serum LH levels was shown in the DEHP group(p<0.05). Graafian follicles and corpora lutea were observed only in the ovaries from the control animals. Numerous primary, secondary follicles and small atretic follicles were observed in the ovaries from DEHP-treated animals. Similarly, hypotrophy of luminal and glandular uterine epithelium was found in the DEHP-treated group. These effects were probably due to the inhibitory effects of DEHP on the synthesis and secretion of estrogen from granulosa cells. In the semiquantitative RT-PCR studies, the transcriptional activities of PR in both ovary(p<0.05) and uterus(p<0.01) from DEHP-treated animals were significantly lower than those from the control animals. The present studies demonstrated that the acute exposure to DEHP during the critical period of prepubertal stage could inactivate the reproductive system resulting delayed puberty in female rats.

An Explanation of Effect of Age Difference in Second Language Acquisition

Youngsoo Lee(이영수) 한국영어학회 2004 영어학 Vol.4 No.4