CRHR1 mediates the transcriptional expression of pituitary hormones and their receptors under hypoxia.

Hypothalamus-pituitary-adrenal (HPA) axis plays critical roles in stress responses under challenging conditions such as hypoxia, regulating gene expression and integrating activities of hypothalamus-pituitary-targets cells. However, the transcriptional regulatory mechanisms and signaling pathways of hypoxic stress in the pituitary remain to be defined. Here, we report that hypoxia induced dynamic changes in the transcription factors, hormones, and their receptors in the adult rat pituitary.

Functional Diversity of p53 in Human and Wild Animals.

The common understanding of p53 function is a genome guardian, which is activated by diverse stresses stimuli and mediates DNA repair, apoptosis, and cell cycle arrest. Increasing evidence has demonstrated p53 new cellular functions involved in abundant endocrine and metabolic response for maintaining homeostasis. However, is frequently mutant in human cancers, and the mutant p53 (Mut-p53) turns to an "evil" cancer-assistant.

The integration of multiple signaling pathways provides for bidirectional control of CRHR1 gene transcription in rat pituitary cell during hypoxia.

Hypoxia upregulates hypothalamic corticotrophin releasing hormone (CRH) and its receptor type-1 (CRHR1) expression and activates the HPA axis and induces hypoxic sickness and behavioral change. The transcriptional mechanism by which hypoxia differently regulates CRHR1 expression remains unclear. Here we report hypoxia time-dependently induced biphasic expression of CRHR1mRNA in rat pituitary during different physiological status.

Systemic pro-inflammatory response facilitates the development of cerebral edema during short hypoxia.

Background: High-altitude cerebral edema (HACE) is the severe type of acute mountain sickness (AMS) and life threatening. A subclinical inflammation has been speculated, but the exact mechanisms underlying the HACE are not fully understood.

Methods: Human volunteers ascended to high altitude (3860 m, 2 days), and rats were exposed to hypoxia in a hypobaric chamber (5000 m, 2 days).

Adaptive methylation regulation of p53 pathway in sympatric speciation of blind mole rats, Spalax.

Epigenetic modifications play significant roles in adaptive evolution. The tumor suppressor p53, well known for controlling cell fate and maintaining genomic stability, is much less known as a master gene in environmental adaptation involving methylation modifications. The blind subterranean mole rat Spalax eherenbergi superspecies in Israel consists of four species that speciated peripatrically.

Prenatal stress, anxiety and depression: a mechanism involving CRH peptide family.

Prenatal stress (PNS) is associated with increased biological risk for mental disorders such as anxiety and depression later in life, and stress appear to be additive to the PNS influences. Among the most widely cited and accepted alternative hypotheses of anxiety and depression is dysfunction of the HPA axis, a system that is central in orchestrating the stress response. Therefore, understanding how PNS exerts profound effects on the HPA axis and stress-sensitive brain functions including anxiety and depression has significant clinical importance.

Inactivation of corticotropin-releasing hormone-induced insulinotropic role by high-altitude hypoxia.

We have shown that hypoxia reduces plasma insulin, which correlates with corticotropin-releasing hormone (CRH) receptor 1 (CRHR1) in rats, but the mechanism remains unclear. Here, we report that hypobaric hypoxia at an altitude of 5,000 m for 8 h enhances rat plasma CRH, corticosterone, and glucose levels, whereas the plasma insulin and pancreatic ATP/ADP ratio is reduced. In islets cultured under normoxia, CRH stimulated insulin release in a glucose- and CRH-level-dependent manner by activating CRHR1 and thus the cAMP-dependent protein kinase pathway and calcium influx through L-type channels.

Corticotropin-releasing factor receptor type 1 colocalizes with type 2 in corticotropin-releasing factor-containing cellular profiles in rat brain.

Objectives: To investigate whether CRHR1 and CRHR2 are colocalized in CRH-specific neurons in rat brain.

Methods: Double/triple immunofluorescence, and combined in situ hybridization were performed in the PVN, amygdala and hippocampus, and triple immunofluorescence was applied to the median eminence (ME), dorsal raphe (DR) and locus coeruleus (LC).

Results: Both CRHR1 and CRHR2 immunoreactivity were highly coexpressed in the PVN, central nucleus of the amygdala (CeA) and hippocampus.

Overactivation of corticotropin-releasing factor receptor type 1 and aquaporin-4 by hypoxia induces cerebral edema.

Cerebral edema is a potentially life-threatening illness, but knowledge of its underlying mechanisms is limited. Here we report that hypobaric hypoxia induces rat cerebral edema and neuronal apoptosis and increases the expression of corticotrophin releasing factor (CRF), CRF receptor type 1 (CRFR1), aquaporin-4 (AQP4), and endothelin-1 (ET-1) in the cortex. These effects, except for the increased expression of CRF itself, could all be blocked by pretreatment with an antagonist of the CRF receptor CRFR1.

Codon 104 variation of p53 gene provides adaptive apoptotic responses to extreme environments in mammals of the Tibet plateau.

Mutational changes in p53 correlate well with tumorigenesis. Remarkably, however, relatively little is known about the role that p53 variations may play in environmental adaptation. Here we report that codon asparagine-104 (104N) and glutamic acid-104 (104E), respectively, of the p53 gene in the wild zokor (Myospalax baileyi) and root vole (Microtus oeconomus) are adaptively variable, meeting the environmental stresses of the Tibetan plateau.

High-altitude hypoxia induces disorders of the brain-endocrine-immune network through activation of corticotropin-releasing factor and its type-1 receptors.

High-altitude hypoxia can induce physiological dysfunction and mountain sickness, but the underlying mechanism is not fully understood. Corticotrophin-releasing factor (CRF) and CRF type-i receptors (CRFR1) are members of the CRF family and the essential controllers of the physiological activity of the hypothalamo-pituitary-adrenal (HPA) axis and modulators of endocrine and behavioral activity in response to various stressors. We have previously found that high-altitude hypoxia induces disorders of the brain-endocrine-immune network through activation of CRF and CRFR1 in the brain and periphery that include activation of the HPA axis in a time- and dose-dependent manner, impaired or improved learning and memory, and anxiety-like behavioral change.

CRHR1 mediates p53 transcription induced by high altitude hypoxia through ERK 1/2 signaling in rat hepatic cells.

We have previously reported that hypoxia activates corticotrophin-releasing hormone (CRH) and the expression of its type-1 receptor (CRHR1) and induces disorders of the brain-endocrine-immune network. p53 is activated by hypoxia and involved in tumorigenesis and apoptosis. Whether CRHR1 regulates p53 transactivation to further influence apoptotic genes remains unclear.

Gestational hypoxia induces sex-differential methylation of Crhr1 linked to anxiety-like behavior.

Stress during gestation increases vulnerability to disease and changes behavior in offspring. We previously reported that hypoxia and restraint during pregnancy sensitized the hypothalamic-pituitary-adrenal (HPA) axis and induced anxiety-like behavior in the adult offspring. Here, we report that gestational intermittent hypoxia (GIH) elicited a sex-dependent anxiety-like behavior in male P90 offspring and activation of corticotropin-releasing hormone (CRH) and CRH type-1 receptor (CRHR1) mRNA in the hypothalamic paraventricular nucleus (PVN) and in male E19 hypothalamus.

Upregulation of PVN CRHR1 by gestational intermittent hypoxia selectively triggers a male-specific anxiogenic effect in rat offspring.

We previously reported that gestational intermittent hypoxia (GIH) causes anxiety-like behavior in neonatal rats. Here, we showed that the anxiogenic effect was correlated with upregulation of corticotropin-releasing hormone receptor 1 (CRHR1) in the hypothalamic paraventricular nuclei (PVN) by GIH, and was selective to male offspring. The anxiety-like behavior was assessed by both the open field (OF) and elevated plus maze (EPM) tests.

[HIF-1 signal pathway in cellular response to hypoxia].

HIF-1 is composed of HIF-1α and HIF-1β subunits. It promotes target genes transcription under hypoxia and plays essential roles in cell development, physiological adaptations, and pathological processes. In the past 10 years, the research on signaling pathways of HIF-1 in response to cell hypoxia stress, especially on HIF-1α-mediated gene transcription has made great progress.

Cellular adaptation to hypoxia and p53 transcription regulation.

Tumor suppressor p53 is the most frequently mutated gene in human tumors. Meanwhile, under stress conditions, p53 also acts as a transcription factor, regulating the expression of a series of target genes to maintain the integrity of genome. The target genes of p53 can be classified into genes regulating cell cycle arrest, genes involved in apoptosis, and genes inhibiting angiogenesis.

Growth hormone and insulin-like growth factor of naked carp (Gymnocypris przewalskii) in Lake Qinghai: expression in different water environments.

Here, we report the cloning and characterization of growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-II from naked carp (Gymnocypris przewalskii), a native teleost fish of Lake Qinghai in the Qinghai-Tibet Plateau of China. The GH of naked carp encodes for a predicted amino acid sequence showing identities of 63%, 63%, 91% and 94% with cherry salmon, rainbow trout, zebrafish and grass carp, respectively. Compared to common carp and goldfish, evolutionary analysis showed that genome duplication has had less influence on the relaxation of purifying selection in the evolution of naked carp GH.

Evolution and regulation of the downstream gene of hypoxia-inducible factor-1alpha in naked carp (Gymnocypris przewalskii) from Lake Qinghai, China.

The naked carp (Gymnocypris przewalskii) is a native teleost of Lake Qinghai (altitude, 3.2 km) on the Qinghai-Tibet Plateau in China. Hypoxia-inducible factor (HIF)-1alpha of Gymnocypris przewalskii was cloned and a phylogenetic tree for vertebrate HIF-1alpha was constructed.