A hipotalamikus neuronális energiaszint szabályozásának vizsgálata: Az NTPDázok, mint lehetséges energia-regulátorok szerepe a pozitív gonadotropin feedback során. = Regulation of neuronal energy levels in the hypothalamus: NTPDases as possible energy regulators of the positive gonadotrophin feedback.

Pályázatunk fő célja, hogy a serkentő idegi működéshez szükséges celluláris energiaszint „korlátozó”, vagy éppen „megengedő” szerepét vizsgáljuk. A hypothalamicus (HT) NTPDáz3 ATP-szabályzó szerepét a tervezettnél szélesebb spektrumban vizsgáltuk, valamint figyelembe vettük, hogy a HT egyszerre több homeosztatikus funkció idegi központja. Ezért figyelembe vettük az érintett homeosztatikus folyamatokat szabályzó idegi struktúrák átfedéseit és a közös mechanizmusokat. A kísérletek két, egymással szorosan összefüggő folyamat elemzésére terjedtek ki, melyek eredményei a következők szerint foglalhatók össze: 1. A mitokondriális metabolizmus, beleértve az NTPDáz3 aktivitását is, valamint a hypothalamus O2 ellátása, az ösztrusz ciklushoz, illetve annak egyes fázisaihoz igazodó hullámzó tendenciát mutatott; Ez a hullámzó tendencia az állatok több mint 80 %-ában a hypothalamusnak csak az egyik féltekéjében mutatkozott, míg az ellenoldali félteke mitokondriális metabolizmusa a ciklus minden fázisában egyenletes, kiegyenlített tendenciát mutatott. 2. Az ADP-függő 3-as típusú mitokondriális légzés korrelál a korábbi kísérleteink szerint leírt gyors ütemű, nagyszámú hypothalamicus excitatórikus szinapszis létrejöttének és aktivitásának idejével, ami az ösztrusz ciklus proösztrusz-korai ösztrusz fázisainak idejére esik. 3. Az 1-5-ös típusú mitokondriális légzés elemzése azt valószínűsíti, hogy a mitokondriális NTPDáz3 blokkolása átfogóan lassítja a mitokondrium metabolizmusát. | The project’s main goal was to examine the limiting/permissive role of the cellular energy levels in hypothalamic (HT) excitatory neuronal activity. Considering that the HT is the regulatory center of more than one homeostatic systems, investigations on the ATP-regulating activity of hypothalamic NTPDase3 were more detailed than originally outlined. Hypothalamic structural and functional overlaps were considered. Studies included two major lines of experiments with result summarized as follows: 1.) The mitochondrial metabolism, including the NTPDase3 activity, and the hypothalamic O2 supply showed a fluctuating pattern corresponding to the phases of the estrous cycle. This phenomenon could only be observed in either the left or right hypothalamic hemispheres in cca. 80 percent of the animals, while the contralateral hemishere showed no such fluctuations. 2.) The ADP-dependent State 3 (St3) mitochondrial respiration correlates with the rapid generation and function of excitatory synapses during late proestrus and early estrus. 3.) Analysis of St1-5 data imply that inhibition of mitochondrial NTPDase3 function leads to overall down-regulation of mitochondrial metabolism

Endocrine factors in the hypothalamic regulation of food intake in females: a review of the physiological roles and interactions of ghrelin, leptin, thyroid hormones, oestrogen and insulin

Controlling energy homeostasis involves modulating the desire to eat and regulating energy expenditure. The controlling machinery includes a complex interplay of hormones secreted at various peripheral endocrine endpoints, such as the gastrointestinal tract, the adipose tissue, thyroid gland and thyroid hormone-exporting organs, the ovary and the pancreas, and, last but not least, the brain itself. The peripheral hormones that are the focus of the present review (ghrelin, leptin, thyroid hormones, oestrogen and insulin) play integrated regulatory roles in and provide feedback information on the nutritional and energetic status of the body. As peripheral signals, these hormones modulate central pathways in the brain, including the hypothalamus, to influence food intake, energy expenditure and to maintain energy homeostasis. Since the growth of the literature on the role of various hormones in the regulation of energy homeostasis shows a remarkable and dynamic expansion, it is now becoming increasingly difficult to understand the individual and interactive roles of hormonal mechanisms in their true complexity. Therefore, our goal is to review, in the context of general physiology, the roles of the five bestknown peripheral trophic hormones (ghrelin, leptin, thyroid hormones, oestrogen and insulin, respectively) and discuss their interactions in the hypothalamic regulation of food intake

Comparative analysis and functional implications of ligand dependent changes in estrogen- and thyroid hormone receptor expression in the developing cerebellum

Abstract Trophic hormones are important regulators of CNS development and function. In particular, estrogen (E2) and thyroid hormones (THs) regulate cell migration, differentiation, proliferation and synaptogenesis/network formation during cerebellar development. These hormone-regulated events involve the binding of hormone ligands to their cognate receptors that function as transcription factors to activate relevant genes for the adequate orchestration of developmental processes. Recent reports implicate a complex mechanism through which E2 and THs influence the expression levels of each other’s receptors (ERs and TRs) to precisely mediate developmental signals. Here we examined the effects of the presence or absence of E2 and THs on the expression levels of their receptor mRNAs and proteins. Cerebellar granule cell cultures were treated with either E2, T3, T4 or a combination of these hormones, and resulting receptor expression levels were determined by quantitative PCR and Western blot techniques. Results were compared to non-treated controls and to samples obtained from 14-day-old in situ cerebella. Additionally, we determined the effects that glial cells might have on the regulation of ER-TR expression levels. Results show that: (i) ER and TR expression levels depend on the individual or combined presence/absence of E2 and THs; (ii) glial cells are important mediators in the hormonal regulation of neuronal ER-TR expression, and (iii) loss of tissue integrity results in characteristic changes in ER-TR expression levels. These observations suggest that both E2 and THs are required for the precise orchestration of cerebellar development and that alterations in the tissue concentration of either of the hormones may influence signaling mechanisms that are driven by both E2 and THs. Comparison of data from in vitro and in situ samples also revealed a shift in receptor expression levels after loss of tissue integrity, likely indicating possible adjusting/regenerative mechanisms after cerebellar tissue injury

Possible hypothalamic laterality in the central regulation of GnRH release: thoughts that might lead to a novel approach in hypothalamic studies

The midcycle E2 surge induces a synaptic reorganization in the mediobasal hypothalamus (MBH), thus increasing the ratio of stimulatory/inhibitory synapses. This synaptic reorganization disinhibits GnRH neurons and leads to an LH surge. Synaptic functions are energy dependent and require mitochondrial ATP production. Ectonucleoside triphosphate diphosphohydrolase 3 (NTPDase3) may play a crucial role in the regulation of mitochondrial ATP levels in stimulatory MBH neurons. The positive gonadophin feedback involves the generation and function of large numbers of hypothalamic stimulatory synapses, thus, it might be associated with increased mitochondrial ATP production and increased mitochondrial respiration (mr). Anatomically, there are paired brain areas in the two hemispheres and unpaired structures along the anatomical midline. Distinct sides of paired brain areas usually regulate distinct physiological processes, rather than sharing roles to regulate the exact same functions. However, there are certain brain regions with no known functional differences between the two sides. One such brain area is the MBH, which has always been investigated as an unpaired midline structure despite its clearly symmetric anatomical characteristics. Investigation of mr in MBH synaptosomal fractions in our laboratory has indicated that besides ipsylateral intrahypothalamic differences (i.e., differences between the lateral and medial regions of the MBH on the same side) a functional laterality may exist between homologous areas of symmetric hypothalamic structures. Therefore, we have investigated mr rates, with special regard to ADP-dependent state 3 mr, in the MBH with isolated left and right sides. Our initial results imply that the MBH regulation of the E2-induced gonadotrophin surge is unilateral, and that there is an urging need for a technical solution to identify in vivo the dominant hypothalamic side that enters into the positive gonadotrophin phase of the estrous cycle

Ösztrogén- és pajzsmirigyhormon receptorok expressziójának ligandum-függő változásai a fejlődő kisagyban

A kisagy fejlődésében meghatározó szerepet játszanak az úgynevezett trófikus hormonok. Ezek közül is kiemelkednek az ösztrogének és a pajzsmirigy hormonjai, melyek specifikus receptorok aktiválása útján szabályzó szerepet játszanak a sejtmigráció, differenciálódás, sejtproliferáció, valamint a kisagyi összeköttetés-rendszer kiépítésében. Az utóbbi évek irodalmi adatai arra engednek következtetni, hogy az említett két hormoncsalád tagjai kölcsönösen befolyást gyakorolnak egymás receptorainak a kifejeződési szintjeire. A feltételezések szerint egy esetleges, az ösztrogén- és pajzsmirigyhormon receptorok között létező interaktív mechanizmus komplexebb módon, de precízebben szabályozhatja a korai posztnatális szövet-fejlődéstani eseményeket a kisagyban, ezért a kérdés beható vizsgálata élettani és klinikai szempontból is indokolt. Jelen vizsgálatunkban arra a kérdésre kerestünk választ, hogy ösztrogén és az egyes pajzsmirigyhormonok (fiziológiás koncentrációban való) jelenléte vagy hiánya hogyan befolyásolja az adott hormon specifikus receptorának a kifejeződési szintjét primer kisagyi sejttenyészetben. Hét napos patkányok kisagyából készült olyan primer sejttenyészeteket hoztunk létre, melyek vagy tartalmaztak természetes módon szaporodó glia sejteket is, vagy pedig a glia fejlődését kísérletesen blokkoltuk. Ilyen körülmények között, a kísérletesen manipulált hormonális környezetben nem csupán a különálló- és kombinált hormonhatásokat, de a glia jelenlétének vagy hiányának a következményeit is megfigyelhettük. Eredményeinket minden esetben összehasonlítottuk hasonló korú (fejlettségi szintű) in situ kisagyból vett minták mérési eredményeivel. Annak érdekében, hogy átfogóbb képet kapjunk az ösztrogénés pajzsmirigyhormonok receptorainak kifejeződési viszonyairól, Western blot technikával határoztuk meg a receptor fehérjék relatív mennyiségét, és kvalitatív PCR technika alkalmazásával határoztuk meg a vonatkozó receptorok mRNS szintjeit. Eredményeink egyértelműen mutatják, hogy mind az ösztrogén receptorok, mind pedig a pajzsmirigyhormon receptorok kifejezıdési szintje függ mindkét hormon jelenlététől, és azt is kimutattuk, hogy a glia sejtek is fontos szabályozó szerepet töltenek be az egyes vizsgált hormon receptorok expressziójának a szabályozásában. Ugyanakkor az in situ kisagyi mintákkal történt összehasonlító vizsgálatok azt is megmutatták, hogy a szöveti integritás elveszítése is egyértelmű hatással van a vizsgált receptorok mennyiségi viszonyaira, egyúttal felhívva a figyelmet az in vitro és in vivo kísérleti eredmények közötti relevancia-kérdésekre is. Eredményeink határozottan mutatják, hogy a kisagy megfelelő fejlődésében meghatározó szerepe van az ösztrogén és pajzsmirigyhormonok fiziológiás arányának, és arra is adatokat szolgáltatunk, hogy a szöveti integritás elveszítése (szövetsérülés) kompenzációs változásokat idéz élő a fejlődő kisagy nukleáris receptorainak expressziójában

Ligand-induced changes in Oestrogen and thyroid hormone receptor expression in the developing rat cerebellum : A comparative quantitative PCR and Western blot study

Abstract Oestrogen (E2) and thyroid hormones (THs) are key regulators of cerebellar development. Recent reports implicate a complex mechanism through which E2 and THs influence the expression levels of each other's receptors (ERs and TRs) to precisely mediate developmental signals and modulate signal strength. We examined the modulating effects of E2 and THs on the expression levels of their receptor mRNAs and proteins in cultured cerebellar cells obtained from 7-day-old rat pups. Cerebellar granule cell cultures were treated with either E2, THs or a combination of these hormones, and resulting receptor expression levels were determined by quantitative PCR and Western blot techniques. The results were compared to non-treated controls and to samples obtained from 14-day-old in situ cerebella. Additionally, we determined the glial effects on the regulation of ER-TR expression levels. The results show that (i) ER and TR expression depends on the combined presence of E2 and THs; (ii) glial cells mediate the hormonal regulation of neuronal ER-TR expression and (iii) loss of tissue integrity results in characteristic changes in ER-TR expression levels. These observations suggest that both E2 and THs, in adequate amounts, are required for the precise orchestration of cerebellar development and that alterations in the ratio of E2/THs may influence signalling mechanisms involved in neurodevelopment. Comparison of data from in vitro and in situ samples revealed a shift in receptor expression levels after loss of tissue integrity, suggesting that such adjusting/regenerative mechanisms may function after cerebellar tissue injury as well

Ligand-induced changes in Oestrogen and thyroid hormone receptor expression in the developing rat cerebellum: A comparative quantitative PCR and Western blot study

Oestrogen (E2) and thyroid hormones (THs) are key regulators of cerebellar development. Recent reports implicate a complex mechanism through which E2 and THs influence the expression levels of each other’s receptors (ERs and TRs) to precisely mediate developmental signals and modulate signal strength. We examined the modulating effects of E2 and THs on the expression levels of their receptor mRNAs and proteins in cultured cerebellar cells obtained from 7-day-old rat pups. Cerebellar granule cell cultures were treated with either E2, THs or a combination of these hormones, and resulting receptor expression levels were determined by quantitative PCR and Western blot techniques. The results were compared to non-treated controls and to samples obtained from 14-day-old in situ cerebella. Additionally, we determined the glial effects on the regulation of ER-TR expression levels. The results show that (i) ER and TR expression depends on the combined presence of E2 and THs; (ii) glial cells mediate the hormonal regulation of neuronal ER-TR expression and (iii) loss of tissue integrity results in characteristic changes in ER-TR expression levels. These observations suggest that both E2 and THs, in adequate amounts, are required for the precise orchestration of cerebellar development and that alterations in the ratio of E2/THs may influence signalling mechanisms involved in neurodevelopment. Comparison of data from in vitro and in situ samples revealed a shift in receptor expression levels after loss of tissue integrity, suggesting that such adjusting/regenerative mechanisms may function after cerebellar tissue injury as well

Protein flexibility and conformational states of <i>Leishmania</i> antigen eIF-4A: identification of a novel plausible protein adjuvant using comparative genomics and molecular modeling

<div><p>Recent homology modeling studies have identified specific residues (epitope) of the <i>Leishmania</i> RNA helicase protein (LmeIF) that stimulates production of IL-12 cytokine. However, question remains concerning how LmeIF’s N-terminal moiety initiates adjuvant effects. Extensive molecular modeling combining the normal mode analysis (NMA) and molecular dynamics simulations, in the present study, has demonstrated that the LmeIF structure may exist in two different forms corresponding to the extended and collapsed (closed) states of the entire structure. The computational results showed that the two domains of the LmeIF structure tend to undergo large fluctuations in a concerted fashion and have strong effect on the solvent accessible surface of the epitope situated on the N-terminal structure. The conformational freedom of the C-terminal domains may explain why the entire LmeIF protein is not as active as the N-terminal moiety. Thereafter, a comparative genome analysis with subsequent homology modeling and molecular electrostatic potential (MEP) techniques allowed us to predict a novel and plausible RNA helicase (<i>LI</i>-helicase) from the <i>Listeria</i> source with adjuvant property as observed for the Leishmania eIF-4A protein. The structural folding and MEP maps revealed similar topologies of the epitope of both LmeIF and <i>LI</i>-helicase proteins and striking identity in the local disposition of the charged groups.</p> <p>An animated Interactive 3D Complement (I3DC) is available in Proteopedia at <a href="http://proteopedia.org/w/Journal:JBSD:7" target="_blank">http://proteopedia.org/w/Journal:JBSD:7</a></p> </div