RESUMEN
Inflammation, demyelination, and axonal damage to the central nervous system (CNS) are the hallmarks of multiple sclerosis (MS) and its representative animal model, experimental autoimmune encephalomyelitis (EAE). There is scientific evidence for the involvement of growth hormone (GH) in autoimmune regulation. Previous data on the relationship between the GH/insulin like growth factor-1 (IGF-1) axis and MS/EAE are inconclusive; therefore, the aim of our study was to investigate the changes in the GH axis during acute monophasic EAE. The results show that the gene expression of Ghrh and Sst in the hypothalamus does not change, except for Npy and Agrp, while at the pituitary level the Gh, Ghrhr and Ghr genes are upregulated. Interestingly, the cell volume of somatotropic cells in the pituitary gland remains unchanged at the peak of the disease. We found elevated serum GH levels in association with low IGF-1 concentration and downregulated Ghr and Igf1r expression in the liver, indicating a condition resembling GH resistance. This is likely due to inadequate nutrient intake at the peak of the disease when inflammation in the CNS is greatest. Considering that GH secretion is finely regulated by numerous central and peripheral signals, the involvement of the GH/IGF-1 axis in MS/EAE should be thoroughly investigated for possible future therapeutic strategies, especially with a view to improving EAE disease.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Hormona del Crecimiento , Factor I del Crecimiento Similar a la Insulina , Animales , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Encefalomielitis Autoinmune Experimental/genética , Femenino , Ratas , Hormona del Crecimiento/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Factor I del Crecimiento Similar a la Insulina/genética , Hipotálamo/metabolismo , Hipotálamo/patología , Hipófisis/metabolismo , Hipófisis/patología , Receptores de Somatotropina/metabolismo , Receptores de Somatotropina/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Esclerosis Múltiple/metabolismo , Esclerosis Múltiple/patología , Esclerosis Múltiple/genética , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Hormona Liberadora de Hormona del Crecimiento/genética , Hígado/metabolismo , Hígado/patología , Modelos Animales de EnfermedadRESUMEN
Growth hormone-releasing hormone (GHRH) has been widely shown to stimulate growth hormone (GH) production via binding to GHRH receptor GHRHR in various species of vertebrates, but information regarding the functional roles of GHRH and GHRHR in the protochordate amphioxus remains rather scarce. We showed here that two mature peptides, BjGHRH-1 and BjGHRH-2, encoded by BjGHRH precursor, and a single BjGHRHR protein were identified in the amphioxus Branchiostoma. japonicum. Like the distribution profiles of vertebrate GHRHs and GHRHRs, both the genes Bjghrh and Bjghrhr were widely expressed in the different tissues of amphioxus, including in the cerebral vesicle, Hatschek's pit, neural tube, gill, hepatic caecum, notochord, testis and ovary. Moreover, both BjGHRH-1 and BjGHRH-2 interacted with BjGHRHR, and triggered the cAMP/PKA signal pathway in a dose-dependent manner. Importantly, BjGHRH-1 and BjGHRH-2 were both able to activate the expression of GH-like gene in the cells of Hatschek's pit. These indicate that a functional vertebrate-like GHRH-GHRHR axis had already emerged in amphioxus, which is a seminal innovation making physiological divergence including reproduction, growth, metabolism, stress and osmoregulation possible during the early evolution of vertebrates.
Asunto(s)
Hormona Liberadora de Hormona del Crecimiento , Anfioxos , Receptores de Neuropéptido , Receptores de Hormona Reguladora de Hormona Hipofisaria , Animales , Anfioxos/metabolismo , Anfioxos/genética , Receptores de Neuropéptido/metabolismo , Receptores de Neuropéptido/genética , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Hormona Liberadora de Hormona del Crecimiento/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Sistema Hipotálamo-Hipofisario/metabolismoRESUMEN
The negative coordination of growth hormone secretagogue receptor (GHS-R) and growth hormone-releasing hormone receptor (GHRH-R) involves in the repair processes of cellular injury. The allosteric U- or H-like modified GHRH dimer Grinodin and 2Y were comparatively evaluated in normal Kunming mice and hamster infertility models induced by CPA treatment. 1-3-9 µg of Grinodin or 2Y per hamster stem-cell-exhaustion model was subcutaneously administered once a week, respectively inducing 75-69-46 or 45-13-50 % of birth rates. In comparison, the similar mole of human menopausal gonadotropin (hMG) or human growth hormone (hGH) was administered once a day but caused just 25 or 20 % of birth rates. Grinodin induced more big ovarian follicles and corpora lutea than 2Y, hMG, hGH. The hMG-treated group was observed many distorted interstitial cells and more connective tissues and the hGH-treated group had few ovarian follicles. 2Y had a plasma lifetime of 21 days and higher GH release in mice, inducing lower birth rate and stronger individual specificity in reproduction as well as only promoting the proliferation of mesenchymal-stem-cells (MSCs) in the models. In comparison, Grinodin had a plasma lifetime of 30 days and much lower GH release in mice. It significantly promoted the proliferation and activation of ovarian MSCs together with the development of follicles in the models by increasing Ki67 and GHS-R expressions, and decreasing GHRH-R expression in a dose-dependent manner. However, the high GH and excessive estrogen levels in the models showed a dose-dependent reduction in fertility. Therefore, unlike 2Y, the low dose of Grinodin specifically shows low GHS-R and high GHRH-R expressions thus evades GH and estrogen release and improves functions of organs, resulting in an increase of fertility.
Asunto(s)
Proliferación Celular , Células Madre Mesenquimatosas , Ovario , Femenino , Animales , Ratones , Proliferación Celular/efectos de los fármacos , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/metabolismo , Ovario/efectos de los fármacos , Ovario/metabolismo , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Fertilidad/efectos de los fármacos , Receptores de Neuropéptido/metabolismo , Humanos , Regulación Alostérica/efectos de los fármacos , Receptores de Ghrelina/metabolismo , Cricetinae , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , DimerizaciónRESUMEN
Growth hormone (GH) deficiency is a common cause of late sexual maturation and fertility issues. To determine whether GH-induced effects on reproduction are associated with alterations in hypothalamic kisspeptin system, we studied the male reproduction in two distinct GH deficiency mouse models. In the first model, mice present GH deficiency secondary to arcuate nucleus of the hypothalamus (ARH) lesions induced by posnatal monosodium glutamate (MSG) injections. MSG-induced ARH lesions led to significant reductions in hypothalamic Ghrh mRNA expression and consequently growth. Hypothalamic Kiss1 mRNA expression and Kiss1-expressing cells in the ARH were disrupted in the MSG-treated mice. In contrast, kisspeptin immunoreactivity remained preserved in the anteroventral periventricular and rostral periventricular nuclei (AVPV/PeN) of MSG-treated mice. Importantly, ARH lesions caused late sexual maturation and infertility in male mice. In our second mouse model, we studied animals profound GH deficiency due to a loss-of-function mutation in the Ghrhr gene (Ghrhrlit/lit mice). Interestingly, although Ghrhrlit/lit mice exhibited late puberty onset, hypothalamic Kiss1 mRNA expression and hypothalamic kisspeptin fiber density were normal in Ghrhrlit/lit mice. Despite presenting dwarfism, the majority of Ghrhrlit/lit male mice were fertile. These findings suggest that spontaneous GH deficiency during development does not compromise the kisspeptin system. Furthermore, ARH Kiss1-expressing neurons are required for fertility, while AVPV/PeN kisspeptin expression is sufficient to allow maturation of the hypothalamic-pituitary-gonadal axis in male mice.
Asunto(s)
Núcleo Arqueado del Hipotálamo/metabolismo , Hormona del Crecimiento/deficiencia , Sistema Hipotálamo-Hipofisario/metabolismo , Kisspeptinas/metabolismo , Reproducción , Maduración Sexual , Animales , Enanismo/genética , Enanismo/metabolismo , Fertilidad , Kisspeptinas/genética , Masculino , Ratones , Neuronas/metabolismo , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismoRESUMEN
Growth hormone-releasing hormone (GHRH) is a hypothalamic hormone, which regulates the secretion of growth hormone (GH) from the anterior pituitary gland. The effects of GHRH extend beyond the GH-insulin-like growth factor I axis, and that neuropeptide has been involved in the potentiation of several malignancies and other inflammatory disorders. The development of GHRH antagonists (GHRHAnt) delivers an exciting possibility to counteract the pathogenesis of the GHRH-related effects in human pathophysiology, especially when considered that GHRHAnt support endothelial barrier integrity. Those GHRHAnt-mediated effects are exerted at least in part due to the suppression of major inflammatory pathways, and the modulation of major cytoskeletal components. In the present study, we measured the production of reactive oxygen species (ROS) in bovine pulmonary artery endothelial cells, human cerebral microvascular endothelial cells, and human lung microvascular endothelial cells exposed to GHRH or a commercially available GHRHAnt. Our findings reveal the antioxidative effects of GHRHAnt in all three cell lines, which express GHRH receptors. The redox status of NIH/3T3 cells, which do not produce GHRH receptors, was not significantly affected by GHRH or GHRHAnt. Hence, the application of GHRHAnt in pathologies related to increased ROS production should be further investigated.
Asunto(s)
Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Hormona Liberadora de Hormona del Crecimiento/antagonistas & inhibidores , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Bovinos , Línea Celular Transformada , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Hormona Liberadora de Hormona del Crecimiento/farmacología , Humanos , Peróxido de Hidrógeno/metabolismo , Ratones , Células 3T3 NIH , Arteria Pulmonar/citología , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismoRESUMEN
Optic neuropathies are leading causes of irreversible visual impairment and blindness, currently affecting more than 100 million people worldwide. Glaucoma is a group of optic neuropathies attributed to progressive degeneration of retinal ganglion cells (RGCs). We have previously demonstrated an increase in survival of RGCs by the activation of macrophages, whereas the inhibition of macrophages was involved in the alleviation on endotoxin-induced inflammation by antagonist of growth hormone-releasing hormone (GHRH). Herein, we hypothesized that GHRH receptor (GHRH-R) signaling could be involved in the survival of RGCs mediated by inflammation. We found the expression of GHRH-R in RGCs of adult rat retina. After optic nerve crush, subcutaneous application of GHRH agonist MR-409 or antagonist MIA-602 promoted the survival of RGCs. Both the GHRH agonist and antagonist increased the phosphorylation of Akt in the retina, but only agonist MR-409 promoted microglia activation in the retina. The antagonist MIA-602 reduced significantly the expression of inflammation-related genes Il1b, Il6, and Tnf Moreover, agonist MR-409 further enhanced the promotion of RGC survival by lens injury or zymosan-induced macrophage activation, whereas antagonist MIA-602 attenuated the enhancement in RGC survival. Our findings reveal the protective effect of agonistic analogs of GHRH on RGCs in rats after optic nerve injury and its additive effect to macrophage activation, indicating a therapeutic potential of GHRH agonists for the protection of RGCs against optic neuropathies especially in glaucoma.
Asunto(s)
Hormona Liberadora de Hormona del Crecimiento/agonistas , Macrófagos/patología , Neuroprotección , Traumatismos del Nervio Óptico/patología , Células Ganglionares de la Retina/patología , Animales , Supervivencia Celular/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Hormona del Crecimiento/metabolismo , Hormona Liberadora de Hormona del Crecimiento/antagonistas & inhibidores , Inflamación/genética , Inflamación/patología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Neuroprotección/efectos de los fármacos , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas Endogámicas F344 , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Células Ganglionares de la Retina/efectos de los fármacos , Células Ganglionares de la Retina/metabolismo , Factor de Transcripción STAT3/metabolismo , Sermorelina/análogos & derivados , Sermorelina/farmacología , Transducción de Señal/efectos de los fármacos , Cuerpo Vítreo/efectos de los fármacos , Cuerpo Vítreo/metabolismo , Zimosan/farmacologíaRESUMEN
The classic concept of how pituitary GH is regulated by somatostatin and GHRH has changed in recent years, following the discovery of peripheral hormones involved in the regulation of energy homeostasis and mineral homeostasis. These hormones are ghrelin, nesfatins, and klotho. Ghrelin is an orexigenic hormone, released primarily by the gastric mucosa, although it is widely expressed in many different tissues, including the central nervous system and the pituitary. To be active, ghrelin must bind to an n-octanoyl group (n = 8, generally) on serine 3, forming acyl ghrelin which can then bind and activate a G-protein-coupled receptor leading to phospholipase C activation that induces the formation of inositol 1,4,5-triphosphate and diacylglycerol that produce an increase in cytosolic calcium that allows the release of GH. In addition to its direct action on somatotrophs, ghrelin co-localizes with GHRH in several neurons, facilitating its release by inhibiting somatostatin, and acts synergistically with GHRH stimulating the synthesis and secretion of pituitary GH. Gastric ghrelin production declines with age, as does GH. Klotho is an anti-aging agent, produced mainly in the kidneys, whose soluble circulating form directly induces GH secretion through the activation of ERK1/2 and inhibits the inhibitory effect that IGF-I exerts on GH. Children and adults with untreated GH-deficiency show reduced plasma levels of klotho, but treatment with GH restores them to normal values. Deletions or mutations of the Klotho gene affect GH production. Nesfatins 1 and 2 are satiety hormones, they inhibit food intake. They have been found in GH3 cell cultures where they significantly reduce the expression of gh mRNA and that of pituitary-specific positive transcription factor 1, consequently acting as inhibitors of GH production. This is a consequence of the down-regulation of the cAMP/PKA/CREB signaling pathway. Interestingly, nesfatins eliminate the strong positive effect that ghrelin has on GH synthesis and secretion. Throughout this review, we will attempt to broadly analyze the role of these hormones in the complex world of GH regulation, a world in which these hormones already play a very important role.
Asunto(s)
Ghrelina/fisiología , Hormona del Crecimiento/metabolismo , Proteínas Klotho/metabolismo , Nucleobindinas/metabolismo , Animales , Ácidos Grasos/metabolismo , Eliminación de Gen , Ghrelina/metabolismo , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Hormona de Crecimiento Humana/sangre , Humanos , Factor I del Crecimiento Similar a la Insulina/metabolismo , Ratones , Mutación , Hipófisis/metabolismo , Dominios Proteicos , ARN Mensajero/metabolismo , Ratas , Receptores de Ghrelina/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Yanbian yellow cattle breeding is limited by slow growth. We previously found that the miRNA miR-93 was differentially expressed between the blood exosomes of Yanbian yellow cattle and Han Yan cattle, which differ in growth characteristics. In this experiment, we evaluated the effects of miR-93 on growth hormone (GH) secretion by pituitary cells of Yanbian yellow cattle using qPCR, Western blot, Targetscan and RNA hybrid analysis software and Dual-Luciferase reporter gene system. The results showed that miR-93 targeted 3' UTR of GHRHR(growth hormone releasing hormone receptor); GH mRNA and protein levels in pituitary cells of Yanbian yellow cattle were significantly lower in the miR-93-mi group than in the NC control group (p < 0.01), while GH mRNA and protein levels were higher in the miR-93-in group than in the iNC control group, but the difference was not significant (p > 0.05); GHRHR mRNA and protein levels were significantly lower in the miR-93-mi group than in the NC control group (p < 0.01), while GHRHR protein levels were significantly higher in the miR-93-in group than in the iNC control group (p < 0.05), but there was no significant difference about GHRHR mRNA level between two groups (p > 0.05). These results prove that miR-93 regulates GH secretion in pituitary cells via GHRHR.
Asunto(s)
Bovinos/genética , Hormona del Crecimiento/metabolismo , MicroARNs/genética , Hipófisis/citología , Animales , Regulación de la Expresión Génica/fisiología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismoRESUMEN
Mice carrying an RGS-insensitive Gαi2 mutation display growth retardation early after birth. Although the growth hormone (GH)-axis is a key endocrine modulator of postnatal growth, its functional state in these mice has not been characterized. The present study was undertaken to address this issue. Results revealed that pituitary mRNA levels for GH, prolactin (PRL), somatostatin (SST), GH-releasing-hormone receptor (GHRH-R) and GH secretagogue receptor (GHS-R) were decreased in mutants compared to controls. These changes were reflected by a significant decrease in plasma levels of GH, IGF-1 and IGF-binding protein-3 (IGFBP-3). Mutants were also less responsive to GHRH and ghrelin (GhL) on GH stimulation of release from pituitary primary cell cultures. In contrast, they were more sensitive to the inhibitory effect of SST. These data provide the first evidence for an alteration of the functional state of the GH-axis in Gαi2G184S mice that likely contributes to their growth retardation.
Asunto(s)
Subunidad alfa de la Proteína de Unión al GTP Gi2/genética , Trastornos del Crecimiento/genética , Trastornos del Crecimiento/metabolismo , Proteínas RGS/metabolismo , Transducción de Señal/genética , Animales , Células Cultivadas , Femenino , Subunidad alfa de la Proteína de Unión al GTP Gi2/metabolismo , Ghrelina/farmacología , Hormona del Crecimiento/sangre , Hormona del Crecimiento/genética , Hormona del Crecimiento/metabolismo , Hormona Liberadora de Hormona del Crecimiento/sangre , Hormona Liberadora de Hormona del Crecimiento/genética , Hormona Liberadora de Hormona del Crecimiento/farmacología , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación , Hipófisis/efectos de los fármacos , Hipófisis/metabolismo , Prolactina/genética , Prolactina/metabolismo , Proteínas RGS/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Ghrelina/metabolismo , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Transducción de Señal/efectos de los fármacos , Somatostatina/genética , Somatostatina/metabolismo , Somatostatina/farmacologíaRESUMEN
Growth hormone-releasing hormone (GHRH) regulates the secretion of growth hormone that virtually controls metabolism and growth of every tissue through its binding to the cognate receptor (GHRHR). Malfunction in GHRHR signaling is associated with abnormal growth, making GHRHR an attractive therapeutic target against dwarfism (e.g., isolated growth hormone deficiency, IGHD), gigantism, lipodystrophy and certain cancers. Here, we report the cryo-electron microscopy (cryo-EM) structure of the human GHRHR bound to its endogenous ligand and the stimulatory G protein at 2.6 Å. This high-resolution structure reveals a characteristic hormone recognition pattern of GHRH by GHRHR, where the α-helical GHRH forms an extensive and continuous network of interactions involving all the extracellular loops (ECLs), all the transmembrane (TM) helices except TM4, and the extracellular domain (ECD) of GHRHR, especially the N-terminus of GHRH that engages a broad set of specific interactions with the receptor. Mutagenesis and molecular dynamics (MD) simulations uncover detailed mechanisms by which IGHD-causing mutations lead to the impairment of GHRHR function. Our findings provide insights into the molecular basis of peptide recognition and receptor activation, thereby facilitating the development of structure-based drug discovery and precision medicine.
Asunto(s)
Hormona Liberadora de Hormona del Crecimiento/química , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Receptores de Neuropéptido/química , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/química , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Sitios de Unión , Microscopía por Crioelectrón , Enanismo Hipofisario/genética , Proteínas de Unión al GTP , Hormona Liberadora de Hormona del Crecimiento/deficiencia , Humanos , Simulación de Dinámica Molecular , Mutagénesis , Mutación , Conformación Proteica , Conformación Proteica en Hélice alfa , Receptores de Neuropéptido/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Transducción de SeñalRESUMEN
In normal individuals, pituitary somatotrophs optimise body composition by responding to metabolic signals from leptin. To identify mechanisms behind the regulation of somatotrophs by leptin, we used Cre-LoxP technology to delete leptin receptors (LEPR) selectively in somatotrophs and developed populations purified by fluorescence-activated cell sorting (FACS) that contained 99% somatotrophs. FACS-purified, Lepr-null somatotrophs showed reduced levels of growth hormone (GH), growth hormone-releasing hormone receptor (GHRHR), and Pou1f1 proteins and Gh (females) and Ghrhr (both sexes) mRNAs. Pure somatotrophs also expressed thyroid-stimulating hormone (TSH) and prolactin (PRL), both of which were reduced in pure somatotrophs lacking LEPR. This introduced five gene products that were targets of leptin. In the present study, we tested the hypothesis that leptin is both a transcriptional and a post-transcriptional regulator of these gene products. Our tests showed that Pou1f1 and/or the Janus kinase/signal transducer and activator of transcription 3 transcriptional regulatory pathways are implicated in the leptin regulation of Gh or Ghrhr mRNAs. We then focused on potential actions by candidate microRNAs (miRNAs) with consensus binding sites on the 3' UTR of Gh or Ghrhr mRNAs. Somatotroph Lepr-null deletion mutants expressed elevated levels of miRNAs including miR1197-3p (in females), miR103-3p and miR590-3p (both sexes), which bind Gh mRNA, or miRNA-325-3p (elevated in both sexes), which binds Ghrhr mRNA. This elevation indicates repression of translation in the absence of LEPR. In addition, after detecting binding sites for Musashi on Tshb and Prl 3' UTR, we determined that Musashi1 repressed translation of both mRNAs in in vitro fluc assays and that Prl mRNA was enriched in Musashi immunoprecipitation assays. Finally, we tested ghrelin actions to determine whether its nitric oxide-mediated signalling pathways would restore somatotroph functions in deletion mutants. Ghrelin did not restore either GHRH binding or GH secretion in vitro. These studies show an unexpectedly broad role for leptin with respect to maintaining somatotroph functions, including the regulation of PRL and TSH in subsets of somatotrophs that may be progenitor cells.
Asunto(s)
Hipófisis/citología , Hipófisis/metabolismo , Procesamiento Proteico-Postraduccional , Somatotrofos/metabolismo , Animales , Femenino , Regulación de la Expresión Génica/fisiología , Ghrelina/farmacología , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Masculino , Ratones , Ratones Noqueados , MicroARNs/genética , Mutación/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas de Unión al ARN/metabolismo , Receptores de Leptina/genética , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Tirotropina/farmacología , Factor de Transcripción Pit-1/metabolismoRESUMEN
p53 universe is composed of a complex regulatory network, destined to counteract multifarious challenges threatening cell survival. Imbalance in those responses may result in human disease associated with inevitable consequences. The present work delivers our view of the corresponding phenomena, by involving the endothelium defender in meticulously orchestrated events against inflammatory stimuli. Immersing into the great depths of p53 cosmos may lead to promising therapies against devastating disorders, including acute respiratory distress syndrome.
Asunto(s)
Proteínas HSP90 de Choque Térmico/metabolismo , Proteínas HSP90 de Choque Térmico/fisiología , Proteína p53 Supresora de Tumor/fisiología , Animales , ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , Estrés del Retículo Endoplásmico , Endotelio/metabolismo , Humanos , Inflamación/metabolismo , Pulmón/metabolismo , Masculino , Ratones , Neoplasias/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Hiperplasia Prostática/metabolismo , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Ocular inflammation is a major cause of visual impairment attributed to dysregulation of the immune system. Previously, we have shown that the receptor for growth-hormone-releasing hormone (GHRH-R) affects multiple inflammatory processes. To clarify the pathological roles of GHRH-R in acute ocular inflammation, we investigated the inflammatory cascades mediated by this receptor. In human ciliary epithelial cells, the NF-κB subunit p65 was phosphorylated in response to stimulation with lipopolysaccharide (LPS), resulting in transcriptional up-regulation of GHRH-R. Bioinformatics analysis and coimmunoprecipitation showed that GHRH-R had a direct interaction with JAK2. JAK2, but not JAK1, JAK3, and TYK2, was elevated in ciliary body and iris after treatment with LPS in a rat model of endotoxin-induced uveitis. This elevation augmented the phosphorylation of STAT3 and production of proinflammatory factors, including IL-6, IL-17A, COX2, and iNOS. In explants of iris and ciliary body, the GHRH-R antagonist, MIA-602, suppressed phosphorylation of STAT3 and attenuated expression of downstream proinflammatory factors after LPS treatment. A similar suppression of STAT3 phosphorylation was observed in human ciliary epithelial cells. In vivo studies showed that blocking of the GHRH-R/JAK2/STAT3 axis with the JAK inhibitor Ruxolitinib alleviated partially the LPS-induced acute ocular inflammation by reducing inflammatory cells and protein leakage in the aqueous humor and by repressing expression of STAT3 target genes in rat ciliary body and iris and in human ciliary epithelial cells. Our findings indicate a functional role of the GHRH-R/JAK2/STAT3-signaling axis in acute anterior uveitis and suggest a therapeutic strategy based on treatment with antagonists targeting this signaling pathway.
Asunto(s)
Células Epiteliales/patología , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Transducción de Señal/inmunología , Uveítis/patología , Animales , Línea Celular , Cuerpo Ciliar/citología , Modelos Animales de Enfermedad , Células Epiteliales/efectos de los fármacos , Células Epiteliales/inmunología , Humanos , Janus Quinasa 2/metabolismo , Lipopolisacáridos/inmunología , Masculino , Nitrilos , Pirazoles/farmacología , Pirazoles/uso terapéutico , Pirimidinas , Ratas , Receptores de Neuropéptido/antagonistas & inhibidores , Receptores de Neuropéptido/inmunología , Receptores de Hormona Reguladora de Hormona Hipofisaria/antagonistas & inhibidores , Receptores de Hormona Reguladora de Hormona Hipofisaria/inmunología , Factor de Transcripción STAT3/metabolismo , Sermorelina/análogos & derivados , Sermorelina/farmacología , Sermorelina/uso terapéutico , Transducción de Señal/efectos de los fármacos , Uveítis/tratamiento farmacológico , Uveítis/inmunologíaRESUMEN
Growth hormone-releasing hormone (GHRH) antagonist MIA-690 and GHRH agonist MR-409, previously synthesized and developed by us have demonstrated potent antitumor effects. However, little is known about the effects of these analogs on brain functions. We investigated the potential antinflammatory and antioxidant effects of GHRH antagonist MIA-690 and GHRH agonist MR-409, on isolated mouse prefrontal cortex specimens treated with lipopolysaccharide (LPS). Additionally, we studied their effects on emotional behavior after chronic in vivo treatment. Ex vivo, MIA-690 and MR-409 inhibited LPS-induced inflammatory and pro-oxidative markers. In vivo, both MIA-690 and MR-409 induced anxiolytic and antidepressant-like effects, increased norepinephrine and serotonin levels and decreased nuclear factor-kB, tumor necrosis factor-α and interleukin-6 gene expression in prefrontal cortex. Increased nuclear factor erythroid 2-related factor 2 expression was also found in mice treated with MIA-690 and MR-409. MIA-690 showed higher efficacy in inhibiting all tested inflammatory and oxidative markers. In addition, MR-409 induced a down regulation of the gene and protein expression of pituitary-type GHRH-receptor in prefrontal cortex of mice after 4 weeks of treatment at 5 µg/day. In conclusion, our results demonstrate anxiolytic and antidepressant-like effects of GHRH analogs that could involve modulatory effects on monoaminergic signaling, inflammatory and oxidative status.
Asunto(s)
Antiinflamatorios , Antioxidantes , Conducta Animal/efectos de los fármacos , Emociones/efectos de los fármacos , Hormona Liberadora de Hormona del Crecimiento/agonistas , Hormona Liberadora de Hormona del Crecimiento/antagonistas & inhibidores , Sermorelina/análogos & derivados , Animales , Ansiolíticos , Antidepresivos , Expresión Génica/efectos de los fármacos , Interleucina-6/genética , Interleucina-6/metabolismo , Ratones , FN-kappa B/genética , FN-kappa B/metabolismo , Norepinefrina/metabolismo , Corteza Prefrontal/metabolismo , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Sermorelina/farmacología , Serotonina/metabolismo , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Isolated growth hormone (GH) deficiency (IGHD) affects approximately 1 in 4,000 to 1 in 10,000 individuals worldwide. We have previously described a large cohort of subjects with IGHD due to a homozygous mutation in the GH releasing hormone (GHRH) receptor gene. These subjects exhibit throughout the life very low levels of GH and its principal mediator, the Insulin Growth Factor-I (IGF-I). The facilitating role of IGF-I in the infection of mouse macrophages by different Leishmania strains is well-known. Nevertheless, the role of IGF-I in Leishmania infection of human macrophages has not been studied. This study aimed to evaluate the behavior of Leishmania infection in vitro in macrophages from untreated IGHD subjects. To this end, blood samples were collected from 14 IGHD individuals and 14 age and sex-matched healthy controls. Monocytes were isolated and derived into macrophages and infected with a strain of Leishmania amazonensis. In addition, IGF-I was added to culture medium to evaluate its effect on the infection. Cytokines were measured in the culture supernatants. We found that macrophages from IGHD subjects were less prone to Leishmania infection compared to GH sufficient controls. Both inflammatory and anti-inflammatory cytokines increase only in the supernatants of the control macrophages. Addition of IGF-I to the culture medium increased infection rates. In conclusion, we demonstrated that IGF-I is crucial for Leishmania infection of human macrophages.
Asunto(s)
Enanismo Hipofisario/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Leishmania mexicana/metabolismo , Leishmaniasis/inmunología , Macrófagos/metabolismo , Mutación , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Adulto , Animales , Citocinas/metabolismo , Femenino , Humanos , Leishmaniasis/microbiología , Masculino , Ratones , Persona de Mediana Edad , Fagocitosis , ARN Mensajero/metabolismo , Receptores de Neuropéptido/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Adulto JovenRESUMEN
Isolated growth hormone deficiency type II (IGHD2) is mainly caused by heterozygous splice-site mutations in intron 3 of the GH1 gene. A dominant-negative effect of the mutant GH lacking exon 3 on wild-type GH secretion has been proposed; however, the molecular mechanisms involved are elusive. To uncover the molecular systems underlying GH deficiency in IGHD2, we established IGHD2 model mice, which carry both wild-type and mutant copies of the human GH1 gene, replacing each of the endogenous mouse Gh loci. Our IGHD2 model mice exhibited growth retardation along with intact cellular architecture and mildly activated endoplasmic reticulum stress in the pituitary gland, caused by decreased GH-releasing hormone receptor (Ghrhr) and Gh gene promoter activities. Decreased Ghrhr and Gh promoter activities were likely caused by reduced levels of nuclear CREB3L2, which was demonstrated to stimulate Ghrhr and Gh promoter activity. To our knowledge, this is the first in vivo study to reveal a novel molecular mechanism of GH deficiency in IGHD2, representing a new paradigm that differs from widely accepted models.
Asunto(s)
Enanismo Hipofisario/etiología , Hormona del Crecimiento/metabolismo , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Enanismo Hipofisario/patología , Femenino , Hormona del Crecimiento/genética , Humanos , Masculino , Ratones , Hipófisis/metabolismo , Hipófisis/ultraestructura , Regiones Promotoras Genéticas , Receptores de Neuropéptido/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/genéticaRESUMEN
In this article, we briefly review the identification of GHRH, provide an abridged overview of GHRH antagonists, and focus on studies with GHRH agonists. Potent GHRH agonists of JI and MR class were synthesized and evaluated biologically. Besides the induction of the release of pituitary GH, GHRH analogs promote cell proliferation and exert stimulatory effects on various tissues, which express GHRH receptors (GHRH-Rs). A large body of work shows that GHRH agonists, such as MR-409, improve pancreatic ß-cell proliferation and metabolic functions and facilitate engraftment of islets after transplantation in rodents. Accordingly, GHRH agonists offer a new therapeutic approach to treating diabetes. Various studies demonstrate that GHRH agonists promote repair of cardiac tissue, producing improvement of ejection fraction and reduction of infarct size in rats, reduction of infarct scar in swine, and attenuation of cardiac hypertrophy in mice, suggesting clinical applications. The presence of GHRH-Rs in ocular tissues and neuroprotective effects of GHRH analogs in experimental diabetic retinopathy indicates their possible therapeutic applications for eye diseases. Other effects of GHRH agonists, include acceleration of wound healing, activation of immune cells, and action on the central nervous system. As GHRH might function as a growth factor, we examined effects of GHRH agonists on tumors. In vitro, GHRH agonists stimulate growth of human cancer cells and upregulate GHRH-Rs. However, in vivo, GHRH agonists inhibit growth of human cancers xenografted into nude mice and downregulate pituitary and tumoral GHRH-Rs. Therapeutic applications of GHRH analogs are discussed. The development of GHRH analogs should lead to their clinical use.
Asunto(s)
Diabetes Mellitus/tratamiento farmacológico , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Neoplasias/tratamiento farmacológico , Receptores de Neuropéptido/agonistas , Receptores de Hormona Reguladora de Hormona Hipofisaria/agonistas , Animales , Línea Celular Tumoral , Humanos , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismoRESUMEN
Malignant pleural mesothelioma (MPM) is an aggressive malignancy associated with exposure to asbestos, with poor prognosis and no effective therapies. The strong inhibitory activities of growth hormone-releasing hormone (GHRH) antagonists have been demonstrated in different experimental human cancers, including lung cancer; however, their role in MPM remains unknown. We assessed the effects of the GHRH antagonists MIA-602 and MIA-690 in vitro in MPM cell lines and in primary MPM cells, and in vivo in MPM xenografts. GHRH, GHRH receptor, and its main splice variant SV1 were found in all the MPM cell types examined. In vitro, MIA-602 and MIA-690 reduced survival and proliferation in both MPM cell lines and primary cells and showed synergistic inhibitory activity with the chemotherapy drug pemetrexed. In MPM cells, GHRH antagonists also regulated activity and expression of apoptotic molecules, inhibited cell migration, and reduced the expression of matrix metalloproteinases. These effects were accompanied by impairment of mitochondrial activity and increased production of reactive oxygen species. In vivo, s.c. administration of MIA-602 and MIA-690 at the dose of 5 µg/d for 4 wk strongly inhibited the growth of MPM xenografts in mice, along with reduction of tumor insulin-like growth factor-I and vascular endothelial growth factor. Overall, these results suggest that treatment with GHRH antagonists, alone or in association with chemotherapy, may offer an approach for the treatment of MPM.
Asunto(s)
Antineoplásicos/farmacología , Hormona Liberadora de Hormona del Crecimiento/antagonistas & inhibidores , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Mesotelioma/metabolismo , Mesotelioma/patología , Neoplasias Pleurales/metabolismo , Neoplasias Pleurales/patología , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Expresión Génica , Hormona Liberadora de Hormona del Crecimiento/genética , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Mesotelioma/tratamiento farmacológico , Mesotelioma Maligno , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Neoplasias Pleurales/tratamiento farmacológico , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Purpose: The aim of the study was to investigate the signaling of growth hormone-releasing hormone receptor (GHRH-R) in the pathogenesis of pterygium and determine the apoptotic effect of GHRH-R antagonist on pterygium epithelial cells (PECs). Methods: Fourteen samples of primary pterygium of grade T3 with size of corneal invasion ≥ 4 mm were obtained for investigation by histology, immunofluorescence, electron microscopy, explant culture, and flow cytometry. Results: We found that PECs were localized in the basal layer of the epithelium in advancing regions of the head of pterygium. These cells harbored clusters of rough endoplasmic reticulum, ribosomes, and mitochondria, which were consistent with their aggressive proliferation. Immunofluorescence studies and Western blots showed that GHRH-R and the downstream growth hormone receptor (GH-R) were intensively expressed in PECs. Their respective ligands, GHRH and GH, were also elevated in the pterygium tissues as compared to conjunctival cells. Explanted PECs were strongly immunoreactive to GHRH-R and exhibited differentiation and proliferation that led to lump formation. Treatment with GHRH-R antagonist MIA-602 induced apoptosis of PECs in a dose-dependent manner, which was accompanied by a downregulation of ERK1 and upregulation of Caspase 3 expression. Conclusions: Our results revealed that GHRH-R signaling is involved in survival and proliferation of PECs and suggest a potential therapeutic approach for GHRH-R antagonist in the treatment of pterygium.
Asunto(s)
Apoptosis/efectos de los fármacos , Pterigion/patología , Receptores de Neuropéptido/antagonistas & inhibidores , Receptores de Hormona Reguladora de Hormona Hipofisaria/antagonistas & inhibidores , Sermorelina/análogos & derivados , Western Blotting , Caspasa 3/metabolismo , Recuento de Células , Proliferación Celular , Supervivencia Celular , Células Epiteliales/metabolismo , Células Epiteliales/patología , Técnica del Anticuerpo Fluorescente Indirecta , Hormona del Crecimiento/metabolismo , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Humanos , Microscopía Electrónica de Transmisión , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Pterigion/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Receptores de Somatotropina/metabolismo , Sermorelina/farmacología , Transducción de SeñalRESUMEN
Phoenixin (Pnx) is an endogenous peptide known to be involved in reproduction and food intake in rats, with two active isoforms, phoenixin-14 (Pnx-14) and phoenixin-20 (Pnx-20). However, little is known about the functions of Pnx in teleost. Here, pnx was cloned and was detected in all tissues of both male and female in spotted scat (Scatophagus argus), including growth axis, hypothalamus, pituitary, and liver. Real-time PCR analysis showed that pnx in the hypothalamus increased significantly after 2â¯d and 7â¯d fasting, while reduced significantly after re-feeding (Pâ¯<â¯0.05). When pituitary and liver fragments were cultured in vitro with Pnx-14 and Pnx-20 (10â¯nM and 100â¯nM) for 6â¯h, the expression of ghrhr (growth hormone-releasing hormone receptor) and gh (growth hormone) in the pituitary, and ghr1 (growth hormone receptor 1) in the liver increased significantly, except ghr2 (growth hormone receptor 2) incubated with 10â¯nM and 100â¯nM Pnx-20 and ghr1 incubated with 10â¯nM Pnx-20. Similarly, the expression of ghrhr and gh in the pituitary, as well as ghr1 and ghr2 in the liver, increased significantly after injecting S. argus with Pnx-14 and Pnx-20 (10â¯ng/g and 100â¯ng/g body weight). These results indicate that Pnx is likely to be involved in the regulation of food intake, and also regulates the growth of S. argus by increasing ghrhr and gh expression in the pituitary, ghr1 and ghr2 in the liver, and ghr1 directly in the liver.