Development of kisspeptin-GnRH neural circuit in utero and mapping of GnRH receptor neurons in mice brain

'Gonadotropin releasing hormone (GnRH)'-Neurone repräsentieren die gemeinsame ZNS-Endstrecke zur hormonalen Kontrolle der Keimdrüsen. Dabei unterliegt die GnRH-Freisetzung einer Feedback-Regulation durch das gonadale Steroidhormon Östrogen. GnRH-Neurone exprimieren selbst allerdings nicht Östrogen-Rezeptor-alpha (ER), was nahelegt, dass das Feedback-Signal über einen vorgeschalteten Steroid-sensitiven Signalweg auf GnRH-Neurone übertragen wird. Tatsächlich fungieren 'Kisspeptin'-Neurone als Upstream-Regulator der GnRH-Freisetzung und dienen als Angriffspunkt für Steroidhormone in der Regulation der GnRH-Sekretion. GnRH-Neurone exprimieren den Kisspeptin-Rezeptor GPR54. Kisspeptin-Neurone sind im Gehirn vor allem im Nucleus arcuatus (ARC) und im anterolateralen Nucleus paraventricularis (AVPV) lokalisiert. Kisspeptin-Neurone projizieren in die mediane Eminenz und auf GnRH-Neurone der prä-optischen Region. Kisspeptin bindet an GPR54 und stimuliert GnRH-Neurone der prä-optischen Region zur GnRH-Freisetzung in die Zirkulation. In der vorliegenden Arbeit wurde das genaue raumzeitliche Expressionsmuster der dem GnRH-Neuron vor- und nachgeschaltetem Neuronensysteme, des 'Kisspeptin'-Systems und des GnRH-exprimierenden Systems, bestimmt. Dazu wurde zunächst das Einsetzen der Expression von Kisspeptin und seinem Rezeptor GPR54 in männlichen KissIC/eR26-GFP-Embryonen sowie in männlichen GPIC/eR26-GFP-Embryonen untersucht. Kisspeptin und GPR54 erschienen gleichzeitig am Embryonaltag E13.5. Während der ganzen embryonalen Hirnentwicklung wurde Kisspeptin nur im ARC des Hypothalamus gefunden. Hingegen blieb die Expression von GPR54 auf GnRH-Neurone beschränkt. Die detailierte Analyse zeigt jedoch, dass das GPR54-Expressionsmuster unabhängig von der Lage der GnRH-Neuronen war. Zur Bestimmung des Zeitpunkts, an dem Kisspeptin-Neurone sensitiv gegenüber Sexualsteroiden werden, wurde die Expression von Östrogen-Rezeptor ER und von Androgen-Rezeptor (AR) in ARC Kisspeptin-Neuronen untersucht. Es stellte sich heraus, dass ER und AR-positive Neurone die embryonale Hirnregion markieren, in der sich Kisspeptin-Neurone entwickeln. Trans-synaptisches Tracing zeigte schließlich, dass im männlichen embryonalen Mäusegehirn Kisspeptin-Neurone des ARC mit dem GnRH-Neuronensystem kommunizieren. Die Verbindung zwischen ARC-Kisspeptin-Neuronen und GnRH-Neuronen ist unabhängig von der Lage der Neurone im männlichen embryonalen Mäusegehirn. Diese Beobachtung legt den Schluß nahe, dass im Gegensatz zum adulten Gehirn, in dem Kisspeptin-Neurone eine geschlechtsspezifische Verteilung aufweisen, Beginn und Entwicklung des Kisspeptin-GPR54-Systems im männlichen embryonalen Mäusegehirn eher dem weiblichen Mäusegehirn ähneln und dass der Sexualdimorphismus erst später in der Entwicklung entsteht. Es folgte die Untersuchung des Downstream-Targets, dem Gonadotropin releasing hormone receptor (GnRHR)-Neurons. In der Hypophyse triggert GnRH-Rezeptorbindung die Synthese und Freisetzung von Luteinisierungshormon (LH) und von follikelstimulierendem Hormon (FSH). Die Rolle von GnRHR in den gonadotropen Zellen der Hypophyse ist bekannt, aber die Funktion der GnRHR-Neurone im Gehirn ist noch nicht vollständig geklärt. Zur Bearbeitung dieser Frage wurde die Verteilung der GnRHR-Neurone im embryonalen Gehirn von weiblichen GnRHR/eR26-GFP-Mäuseembryonen kartiert. Es stellte sich heraus, dass ihre Anzahl signifikant im Lauf der Entwicklung ansteigt. Die GnRHR-Neuronen reicherten sich in der olfaktorischen Hirnregion und in Sexualzentren wie der medialen Amygdala (MeA), der medialen prä-optischen Region (MPA), dem ventromedialen Hypothalamus (VMH) und der peri-aquaeduktalen grauen Substanz (PAG) an. Die GnRHR-Neuronen der olfaktorischen Regionen und Sexualzentren erwiesen sich als sensitiv gegenüber Sexualsteroiden. Erstmalig konnte die olfaktorische Stimulation von GnRHR-exprierenden Neuronen gezeigt werden. Die Ergebnisse der vorliegende Untersuchung liefern Einblicke in die Entwicklung des Kisspeptin-GPR54-Systems und können zum besseren Verständnis von Störungen der Geschlechtsentwicklung wie dem hypogonadotrophen Hypogonadismus oder der Pubertas praecox beitragen. Die anatomische Kartierung der GnRHR-Neurone im Gehirn beleuchtet die Rolle von GnRH-Signalwegs in der Säugetier-Hypothalamus/Hypophysen/Gonaden-Achse.Gonadotropin releasing hormone (GnRH) neurons are the final common output pathway by which brain controls reproduction. Gonadal steroid hormone, estrogen regulates GnRH release by feedback signaling. Interestingly, GnRH neurons do not express estrogen receptors (ER suggesting that a steroid sensitive pathway might mediate these effects on GnRH neuron. Kisspeptin, a key upstream regulator of GnRH secretion serves as a target for steroid hormone in the control of GnRH secretion. GnRH neurons express kisspeptin receptor, GPR54. Kisspeptin neurons are primarily located in two major locations of the hypothalamus, the arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV). Kisspeptin neurons project to GnRH neurons located in the preoptic area (and to the median eminence). Kisspeptin binds to GPR54 to stimulate GnRH neuron in the preoptic area to release GnRH into the circulation. The goal of this study is to determine the precise spatio-temporal expression pattern of the upstream and the downstream target of GnRH neuron, Kisspeptin system and GnRHR expressing neurons respectively. I examined the onset of kisspeptin and its receptor, GPR54 in the KissIC/eR26-GFP and GPIC/eR26-GFP male mouse embryo respectively. Interestingly expression of Kisspeptin and its receptor GPR54 initiates at the same time (E13.5). Throughout the embryonic brain development kisspeptin neurons remain restricted to the ARC of the hypothalamus whereas GPR54 expression is restricted to the GnRH neuron. Detailed analysis revealed that the GPR54 expression is independent of the location of the GnRH neuron. Next I analyzed when kisspeptin neurons becomes sensitive to gonadal steroid hormones. I investigated the expression of estrogen receptor alpha (ER) and androgen receptor (AR) in the ARC kisspeptin neuron. I observed that ERand AR positive neurons marks the birthplace of kisspeptin neuron in the embryonic brain. Transsynaptic tracing in the embryonic mouse brain revealed that ARC kisspeptin neurons communicate with GnRH neurons in utero. The connectivity between ARC kisspeptin neurons and GnRH neurons is independent of the location of the GnRH neurons in the embryonic male mouse brain. These observations suggests that in contrast to the adult brain where kisspeptin neurons are present in sexually dimorphic manner, onset and the development of Kisspeptin-GPR54 system in embryonic male brain is highly similar to female brain and sexual dimorphism arises later in development. Next, I investigated the downstream target of GnRH neuron, gonadotropin releasing hormone receptor (GnRHR) expressing neurons. GnRH binds to its receptor in pituitary to trigger the synthesis and release of luteinizing hormone (LH) and follicle stimulating hormone (FSH). The role of GnRHR in pituitary gonadotropes is well understood but the function of GnRHR neurons in the brain is not well established. Using GnRHR/eR26-GFP mouse I mapped the distribution of GnRHR neurons in the female brain. I observed that the GnRHR neurons are concentrated in olfactory processing areas and reproductive centers in the brain such as medial amygdala (MeA), medial preoptic area (MPA), ventromedial hypothalamus (VMH) and periaqueductal grey (PAG). I found that the number of GnRHR neurons significantly increases across developmental stage I also observed that GnRHR neurons in olfactory and reproductive centers are sensitive to steroid hormones. For the first time I also identified that GnRHR expressing neurons are activated upon olfactory stimulation. Taken together, the present study provides insight into the (I) development of kisspeptin-GPR54 system which will help to better understand reproductive disorders such as hypogonadotropic hypogonadism and precocious puberty (II) detailed anatomical mapping of GnRHR neurons in the brain will help in understanding the role of GnRH signaling in the mammalian brain and its effect on reproductive axi

Determinant Of Level Of Climate Change Disclosure By Developed And Emerging Countries In Asia Pacific.

Kajian ini bertujuan untuk mengkaji bagaimana tiga belas negara yang melibatkan seratus sebelas syarikat dari sepuluh industri yang berbeza pendedahan laporan mengenai perubahan iklim melalui pengurusan pentadbiran firma This study investigates how well Ill firms in ten industries, across thirteen countries, are addressed climate change through corporate governance characteristics and firm attributes

Efficacy of an Extract of Ocimum tenuiflorum (OciBest) in the Management of General Stress: A Double-Blind, Placebo-Controlled Study

A randomized, double-blind, placebo-controlled study was conducted to evaluate the efficacy of OciBest, an extract of Ocimum tenuiflorum Linn. in symptomatic control of general stress. The participants received either placebo (n = 79) or OciBest (n = 71; 1200 mg of actives per day) for six weeks. The severity of stress-related symptoms was self-evaluated by patients at weeks 0, 2, 4 and 6 of the trial period using a symptom rating scale. After six weeks of intervention, scores of symptoms such as forgetfulness, sexual problems of recent origin, frequent feeling of exhaustion, and frequent sleep problems of recent origin decreased significantly (P ≤ 0.05) in OciBest group as compared with placebo group. Also, the total symptom scores of OciBest group revealed significant reduction (P ≤ 0.05) as compared to placebo group. The overall improvement in OciBest group was found to be 1.6 times or 39% more in the control of general stress symptoms with respect to placebo. No adverse events were reported during the study. The findings revealed that OciBest was found to be effective and well tolerated by all the patients over the six weeks of study period

Efficacy of an Extract of Ocimum tenuiflorum (OciBest) in the Management of General Stress: A Double-Blind, Placebo-Controlled Study

A randomized, double-blind, placebo-controlled study was conducted to evaluate the efficacy of OciBest, an extract of Ocimum tenuiflorum Linn. in symptomatic control of general stress. The participants received either placebo (n = 79) or OciBest (n = 71; 1200 mg of actives per day) for six weeks. The severity of stress-related symptoms was self-evaluated by patients at weeks 0, 2, 4 and 6 of the trial period using a symptom rating scale. After six weeks of intervention, scores of symptoms such as forgetfulness, sexual problems of recent origin, frequent feeling of exhaustion, and frequent sleep problems of recent origin decreased significantly (P ≤ 0.05) in OciBest group as compared with placebo group. Also, the total symptom scores of OciBest group revealed significant reduction (P ≤ 0.05) as compared to placebo group. The overall improvement in OciBest group was found to be 1.6 times or 39% more in the control of general stress symptoms with respect to placebo. No adverse events were reported during the study. The findings revealed that OciBest was found to be effective and well tolerated by all the patients over the six weeks of study period

Augmentation of CFTR maturation by S -nitrosoglutathione reductase

-nitrosoglutathione (GSNO) reductase regulates novel endogenou

Asymmetric cell division of granule neuron progenitors in the external granule layer of the mouse cerebellum

The plane of division of granule neuron progenitors (GNPs) was analysed with respect to the pial surface in P0 to P14 cerebellum and the results showed that there was a significant bias towards the plane of cell division being parallel to pial surface across this developmental window. In addition, the distribution of beta-Catenin in anaphase cells was analysed, which showed that there was a significant asymmetry in the distribution of beta-Catenin in dividing GNPs. Further, inhibition of Sonic Hedgehog (Shh) signalling had an effect on plane of cell division. Asymmetric distribution of beta-Catenin was shown to occur towards the source of a localized extracellular cue