A hipothalamusz-hipofízis-gonád tengely és a humorális immunválasz kölcsönhatásának molekuláris mechanizmusa és szerepe az autoimmun betegségek kialakulásában: neuro-immuno-endokrin kölcsönhatások = Molecular mechanism of hypothalamo-pituitary-gonadal axis and humoral immune response interaction and its role in development of autoimmune disease: neuro-immuno-endocrine interactions

A hypothalamus-hipofizis-gonád (HPG) tengely és az immunrendszer fontos kölcsönhatásban van egymással. Vizsgálatainkban ezen kölcsönhatásnak molekuláris mechanizmusait próbáltuk feltárni. Kísérleteinkben megmutattuk, a HPG tengely irányításában fontos szerepet betöltő GnRH neuronban lévő jelátviteli molekulák, mint az ERK fokozott aktivitást mutat T sejt dependens B sejt immunválasz kialakulásakor a 6. napon nőstény egerekben. Ebben feltehetőleg a citokinek, mint pl. az Il-10 jelentős szerepet játszhatnak. Ez a jelenség T sejt idenpendens B sejt válaszban nem mutatható ki. Megfigyeltük továbbá, hogy az ösztrogén jelentősen növeli a T sejt dependens B sejt immunitásban megfigyelhető ERK foszforilációt a GnRH neuronban. Érdekes módon ezek a változások nem alakították át az állatok ösztrusz ciklusának menetét. A HPG tengely végpontjában felszabaduló ösztrogén jelentősen növelte az antitestek és a B sejetek mennyiségét, és ez a növekedés a T sejtektől függ. A B és a T sejtekben az ösztrogén aktiválta ERK, Akt és NF?B jelátvivő molekulákat azonban csak a T sejtekben indukál növekedést az intraellularis Ca2+ koncentrációban. Az ösztrogén ezeket a nem-klasszikus hatásokat feltehetően a B és T sejtek membránjában meglévő ösztrogén receptorokon keresztül hozza létre. Kísérleti eredményeink fontos támpontot adhatnak a HPG tengely és az immunválasz interakciójának molekuláris mechanizmusaihoz, mely közelebb vihet minket a nemi dimorfizmust mutató autoimmun betegségek megértéséhez is. | Hypothalamo-pituitary-gonadal (HPG) axis has a critical interaction with the immune system. In our experiments, we investigated the molecular mechanism of this particular interaction. Our findings clearly demonstrate that T cell-dependent immune response induces signalling molecule activation, ERK, in the central processor unit of HPG axis, the gonadotropin releasing hormone (GnRH) neuron in female mice at sixth day following immunization. This phenomenon may depend on the cytokines such as Il-10 and it could not be observed in T cell independent immune response. Estrogen further enhances the immune response-induced ERK phospohrylation in GnRH neurons. Interestingly, T cell dependent immune challenge did not alter the estrus cycle. The estrogen, the ?endpoint? of the HPG axis, significantly increases the antibody concentration, the number of B cells and this enhancement highly depends on T cells. Although estrogen induces activation of several signalling molecules such as ERK, Akt and NF?B in B and T cells the estrogen-induced Ca2+ increase was only detected in T cells. It is very likely that estrogen exerts its non-classical actions via estrogen receptors in B and T cells. Taken together, these results shed a light on the molecular mechanism of interaction of HPG axis and immune response. Accordingly, our data may also help to understand the mechanism of certain gender related autoimmune diseases

A T-sejt aktiváció/celluláris immunválasz szabályozása: membrán mikrodomén-függő immunmoduláció és az ösztrogén közvetített nem-genomiális hormonális hatások vizsgálata = Regulation of the T-cell mediated immune response: investigation of membrane microdomain-dependent immunomodulation and estrogen-mediated nongenomial hormonal effects

A T49696 OTKA projekt (3 év) támogatásával elért főbb eredmények: Kimutattuk, hogy a sejtmembrán "tutajok" szfingolipid és koleszterin alkotóelemei fontos szabályozói a T sejtek aktiváció/sejthalál egyensúlyának, valamint a polarizált helper T sejtek válaszképességének. Megmutattuk ezen folyamatokban a ceramidok, a Kv és Cav ioncsatornák alapvető szerepét is. Az általunk leírt szignálintegrációs modell újabb immunmodulációs lehetőségeket kínál. Kimutattuk, hogy az ösztrogén steroid hormonok gyors, nem-genomiális jeleket indukálnak T és B limfocitákon (foszforiláció, szelektív kalcium szignál, stb.), egy még nem azonosított membránreceptoron keresztül, és fokozzák a T sejt-függő, antigén-indukált ellenanyagtermelést. Eredményeink elősegíthetik az ösztrogénszint és egyes autoimmunbetegségek közötti összefüggések hátterének mélyebb megértését. Új, koleszterin-specifikus IgG monoklonális ellenanyagokat (AC1, AC8) állítottunk elő, melyeknek megmutattuk celluláris-koleszterin diagnosztikai célokra történő alkalmazhatóságát. Ezen ellenanyagok képesek a HIV-infekció/ termelés gátlására monocita-makrofág és T sejteken in vitro, elsősorban a célsejtek plazmamembránjának (lipid tutajok, HIV receptorok) molekuláris átrendezése révén. A projekt eredményeit felhasználva 2 PhD tudományos fokozat született; 6 referált tudományos közlemény nemzetközi folyóiratban; 4 új kongresszusi absztrakt, melyekből folyamatos a publikálás (3 publikáció-kész közlemény) | Main results of the project T49696 supported by OTKA (3 years): We have shown that two lipid constituents of rafts (sphingolipids or cholesterol) are critical in regulating the balance of activation/cell death signaling in T cells or the functional responses of polarized Th1 or Th2 cells. Specific, important contribution of ceramides, Kv and Cav ion channels was also shown in these processes, offering new possibilites of immunomodulation. Rapid, non-genomial signals (selective phosphorylation and Ca2+ signals or NFκB nuclear translocation) of estrogen steroid hormones have been shown in both T and B lymphocytes, that may be partly responsible for augmentation of the T-dependent humoral immune response observed in in vivo mice studies. These effects, mediated by a yet unidentified E2 membrane receptor, may help us to reveal and understand the relationship between estrogen levels and several autoimmune diseases. We generated novel cholesterol-specific IgG antibodies (AC1 and AC8), that may serve as diagnostic markers of clustered cholesterol (cell-free or cellular). As one of their most intriguing biological activity - inhibition of HIV entry/production in vitro - has been elucidated and shown that the major mechanism of action is remodeling of the target cells' plasma membrane (rafts and HIV receptors). 2 PhD degrees were received based on these results; 6 reviewed research articles; 4 new Congress Abstracts (publication is continuous: 3 publication-ready manuscripts

Estrogen induces estrogen receptor alpha-dependent cAMP response element-binding protein phosphorylation via mitogen activated protein kinase pathway in basal forebrain cholinergic neurons in vivo

In addition to classical genomic mechanisms, estrogen also exerts nonclassical effects via a signal transduction system on neurons. To study whether estrogen has a nonclassical effect on basal forebrain cholinergic system, we measured the intensity of cAMP response element-binding protein (CREB) phosphorylation (pCREB) in cholinergic neurons after administration of 17 beta-estradiol to ovariectomized (OVX) mice. A significant time-dependent increase in the number of pCREB-positive cholinergic cells was detected after estrogen administration in the medial septum-diagonal band (MS-DB) and the substantia innominata ( SI). The increase was first observed 15 min after estrogen administration. The role of classical estrogen receptors (ERs) was evaluated using ER knock-out mice in vivo. The estrogen-induced CREB phosphorylation in cholinergic neurons was present in ER beta knock-out mice but completely absent in ER beta knock-out mice in MS-DB and SI. A series of in vitro studies demonstrated that estrogen acted directly on cholinergic neurons. Selective blockade of the mitogen activated protein kinase (MAPK) pathway in vivo completely prevented estrogen-induced CREB phosphorylation in cholinergic neurons in MS-DB and SI. In contrast, blockade of protein kinase A (PKA) was effective only in SI. Finally, studies in intact female mice revealed levels of CREB phosphorylation within cholinergic neurons that were similar to those of estrogen-treated OVX mice. These observations demonstrate an ER alpha-mediated nonclassical effect of estrogen on the cholinergic neurons and that these actions are present under physiological conditions. They also reveal the role of MAPK and PKA-MAPK pathway activation in nonclassical estrogen signaling in the basal forebrain cholinergic neurons in vivo

Single-Molecule Imaging Reveals Rapid Estradiol Action on the Surface Movement of AMPA Receptors in Live Neurons

Gonadal steroid 17β-estradiol (E2) exerts rapid, non-genomic effects on neurons and strictly regulates learning and memory through altering glutamatergic neurotransmission and synaptic plasticity. However, its non-genomic effects on AMPARs are not well understood. Here, we analyzed the rapid effect of E2 on AMPARs using single-molecule tracking and super-resolution imaging techniques. We found that E2 rapidly decreased the surface movement of AMPAR via membrane G protein-coupled estrogen receptor 1 (GPER1) in neurites in a dose-dependent manner. The cortical actin network played a pivotal role in the GPER1 mediated effects of E2 on the surface mobility of AMPAR. E2 also decreased the surface movement of AMPAR both in synaptic and extrasynaptic regions on neurites and increased the synaptic dwell time of AMPARs. Our results provide evidence for understanding E2 action on neuronal plasticity and glutamatergic neurotransmission at the molecular level

Live-Cell Imaging of Single Neurotrophin Receptor Molecules on Human Neurons in Alzheimer’s Disease

Neurotrophin receptors such as the tropomyosin receptor kinase A receptor (TrkA) and the low-affinity binding p75 neurotrophin receptor p75NTR play a critical role in neuronal survival and their functions are altered in Alzheimer’s disease (AD). Changes in the dynamics of receptors on the plasma membrane are essential to receptor function. However, whether receptor dynamics are affected in different pathophysiological conditions is unexplored. Using live-cell single-molecule imaging, we examined the surface trafficking of TrkA and p75NTR molecules on live neurons that were derived from human-induced pluripotent stem cells (hiPSCs) of presenilin 1 (PSEN1) mutant familial AD (fAD) patients and non-demented control subjects. Our results show that the surface movement of TrkA and p75NTR and the activation of TrkA- and p75NTR-related phosphoinositide-3-kinase (PI3K)/serine/threonine-protein kinase (AKT) signaling pathways are altered in neurons that are derived from patients suffering from fAD compared to controls. These results provide evidence for altered surface movement of receptors in AD and highlight the importance of investigating receptor dynamics in disease conditions. Uncovering these mechanisms might enable novel therapies for AD

Gyorsított stabilitás vizsgálatok

INST: L_200Gyógyszerfejlesztés során az egyik legkritikusabb a készítmény stabilitása, amely megállapítása sok mintába és hosszú időbe telik. A bomlás hőmérséklet függését az Arrhenius egyenlet adja meg, amelyet szilárd gyógyszerformák esetén bővítenünk kell a páratartalom befolyásoló hatásával is. Ezzel a tapasztalati összefüggéssel kiszámíthatjuk a szükséges stresszkörülményeket a nekünk szükséges szennyező tartalom eléréséhez, ezzel lehetőséget biztosítva a gyors információhoz

Effect of Inflammation on Female Gonadotropin-Releasing Hormone (GnRH) Neurons: Mechanisms and Consequences

Inflammation has a well-known suppressive effect on fertility. The function of gonadotropin-releasing hormone (GnRH) neurons, the central regulator of fertility is substantially altered during inflammation in females. In our review we discuss the latest results on how the function of GnRH neurons is modified by inflammation in females. We first address the various effects of inflammation on GnRH neurons and their functional consequences. Second, we survey the possible mechanisms underlying the inflammation-induced actions on GnRH neurons. The role of several factors will be discerned in transmitting inflammatory signals to the GnRH neurons: cytokines, kisspeptin, RFamide-related peptides, estradiol and the anti-inflammatory cholinergic pathway. Since aging and obesity are both characterized by reproductive decline our review also focuses on the mechanisms and pathophysiological consequences of the impact of inflammation on GnRH neurons in aging and obesity

Sex differences in oestrogen-induced p44/42 MAPK phosphorylation in the mouse brain in vivo

In addition to the classical direct genomic mechanisms of action, oestrogen also exerts poorly understood, nonclassical effects on the signalling system in neurones. In the present study, we investigated whether sex differences exist in gonadectomy- and oestrogen- induced effects on p44/42 mitogen-activated protein kinase (MAPK) phosphorylation in specific brain regions of mice. We demonstrate that MAPK immunoreactivity was not altered by gonadectomy or oestrogen treatment in either sex. However, we show that the level of phosphorylated MAPK (pMAPK) within the anteroventral periventricular nucleus (AVPV) was consistently higher in males than females irrespective of gonadal steroid hormone status. In addition, gonadectomy was found to decrease pMAPK immunoreactivity within the piriform cortex of males. Oestrogen increased pMAPK immunoreactivity in the medial preoptic area and AVPV of females, but failed to have the same effect in male mice. Overall, these results demonstrate a marked sex difference in oestrogen-induced alteration of MAPK phosphorylation in the brain in vivo