Hypoxia-inducible factor 1 (HIF-1), as a main transcriptional regulator of metabolic adaptation to changes in the oxygen environment, participates in many physiological and pathological processes in the body, and is closely related to the pathogenesis of many diseases. This review outlines the mechanisms of HIF-1 activation, its signaling pathways, natural inhibitors, and its roles in diseases. This article can provide new insights in the diagnosis and treatment of human diseases, and recent progress on the development of HIF-1 inhibitors.
Disease ; Humans ; Hypoxia-Inducible Factor 1/physiology* ; Oxygen ; Signal Transduction

Drug metabolism is significantly affected under hypoxia environment with changes of pharmacokinetics, expression and function of drug-metabolizing enzymes and transporters. Studies have shown that hypoxia increases the release of a series of inflammatory cytokines which can modulate drug metabolism. Besides, both hypoxia inducible factor 1α (HIF-1α) and microRNA-mediated pathways play a role in regulating drug metabolism. This article reviewed the impact and single-factor modulating mechanisms of drug metabolism under hypoxia, and put forward the speculation and prospects of multi-factor modulating mechanisms.
Cell Hypoxia ; Humans ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit ; physiology ; Membrane Transport Proteins ; physiology ; MicroRNAs ; physiology ; Pharmaceutical Preparations ; metabolism

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.
Animals ; Cell Hypoxia ; physiology ; Humans ; Hypoxia-Inducible Factor 1 ; metabolism ; Signal Transduction

Hypoxia-inducible factor 1 (HIF-1) has a close relation with prostate cancer. It is involved not only in angiogenesis, cell proliferation/survival and glucose metabolism but also in p53, p21 and signal transduction pathway in prostate cancer. Further studies of HIF-1 may yield new approaches to the diagnosis and treatment of prostate cancer. We present a review of the structure and biological functions of HIF-1 and its relation with prostate cancer.
Humans ; Hypoxia-Inducible Factor 1 ; physiology ; Male ; Prostatic Neoplasms ; diagnosis ; metabolism ; therapy

Hypoxic preconditioning (HPC) refers to exposure of organisms, systems, organs, tissues or cells to moderate hypoxia/ischemia that is able to result in a resistance to subsequent severe hypoxia/ischemia in tissues and cells. The effects exerted by HPC are well documented. The original local in situ (LiHPC) is now broadened to remote ectopic organs-tissues (ReHPC) and extended crossly to cross pluripotential HPC(CpHPC) induced by a variety of stresses other than hypoxia/ischemia, including cancer, for example. We developed a unique animal model of repetitive autohypoxia in adult mice, and studied systematically on the effects and mechanisms of HPC on the model in our laboratory since the early 1960s. The tolerances to hypoxia and protection from injury increased significantly in this model. The adult mice behave like hypoxia-intolerant mammalian newborns and hypoxia-tolerant adult animals during their exposure to repetitive autohypoxia. The overall energy supply and demand decreased, the microorganization of the brain maintained and the spacial learning and memory ability improved but not impaired, the detrimental neurochemicals such as free radicals down-regulated and the beneficial neurochemicals such as adenosine(ADO) and antihypoxic gene(s)/factor(s) (AHGs/AHFs) up-regulated. Accordingly, we hypothesize that mechanisms for the tolerance/protective effects of HPC are fundamentally depending on energy saving and brain plasticity in particular. It is thought that these two major mechanisms are triggered by exposure to hypoxia/ischemia via oxygen sensing-transduction pathways and HIF-1 initiation cascades. We suggest that HPC is an intrinsic mechanism developed in biological evolution and is a novel potential strategy for fighting against hypoxia-ischemia and other stresses. Motivation of endogenous antihypoxic potential, activation of oxygen sensing--signal transduction systems and supplement of exogenous antihypoxic substances as well as development of HPC appliances and HPC medicines such as AHFs are encouraged based on our basic research on HPC. HPC may result in therapeutic augmentation of the endogenous cytoprotection in hypoxic-ischemic or suffering from other diseases' patients. Evolutionary consideration of HPC and clinical implications of HPC are both discussed to guide future research. The product of AHF is expected to be one of the most effective first aid medicines to rescue patients in critical condition. HPC is beginning to be used in surgery and is expected to be developed into a feasible adaptive medicine in the near future.
Animals ; Brain ; physiology ; Disease Models, Animal ; Hypoxia, Brain ; physiopathology ; Hypoxia-Inducible Factor 1 ; Ischemic Preconditioning ; Mice ; Signal Transduction

Acclimatization is a process of biological adaptation when exposed to environmental factors such as hypoxia, cold and heat for prolonged periods of time, where non-genetical variations play a role in allowing subjects to tolerate hypoxic, cold or hot environments. This review focuses on the characteristics and mechanisms of acclimatization found through major research advances by our institute. First, the mechanisms underlying the acclimatization to extreme environments are complex. In our investigations, the physiological changes of multiple systems including the nervous, circulatory, respiratory, and hemopoietic system were demonstrated when the acclimatization to hypoxia was developed, and the underlying significance of hypoxia-inducible factor-1 (HIF-1) was investigated. Second, it is suggested that the development of acclimatization to extreme environments is complicated. Hypoxia and cold coexist at high altitude. Our investigations revealed the characteristics of negative cross-relationship in the acclimatization to hypoxia and cold. And third, it is interesting for us to understand that acclimatization to extreme environments is transferable among individuals, and the characteristics of heat acclimatization-inducing factor (HAlF) were presented. The above findings will provide a theoretical guidance for protective operations and help to establish a solid foundation for future research related to acclimatization.
Acclimatization ; physiology ; Altitude ; Cold Temperature ; Environment ; Hot Temperature ; Humans ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism

Small ubiquitin-like modifier protein (SUMO) modification is a highly dynamic process, catalyzed by SUMO-specific activating (E1), conjugating (E2) and ligating (E3) enzymes, and reversed by a family of SUMO-specific proteases (SENPs). There are six members of the human SENP family, and each SENP has different cellular locations and substrate specificities. However, the precise roles of SENPs in cellular processes have not been elucidated to date. This brief review will focus on recent advances pertaining to the identified targets of SENP1 and its potential role in prostate cancer.
Cysteine Endopeptidases ; Endopeptidases ; physiology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; physiology ; Male ; Prostatic Neoplasms ; physiopathology ; Receptors, Androgen ; physiology ; SUMO-1 Protein ; physiology ; Signal Transduction ; physiology

OBJECTIVETo observe dynamically the development of fetal long bone and detect the expression and distribution of HIF-1alpha,to investigate the expression pattern and possible effects of hypoxia inducible factor-1alpha (HIF-1alpha) in fetal long bone development of mouse.

METHODSE12.5, E13.5, E14.5, E15.5, E16.5 and E17.5 pregnant C57BL6 mice were sacrificed. After sacrifice, the embryos were delivered by caesarean section. The development of fetal long bone was dynamically observed by stereoscopic microscope, and the distributional expression of HIF-1alpha protein was detected by using method of immunohistochemistry. The expression of HIF-1alpha mRNA and osteoblast marker gene at various stage were also detected by using methods of reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSThe cartilaginous long bone began to form and joints outline arised at E13.5, then the primary ossification center was observed at E14.5, showing opaque ossification under stereoscopic microscope,and then the osteogenesis expanded and extended to both sides. Immunohistochemistry demonstrated lots of HIF-1alpha protein positive chondrcytes in the center of primary ossification at E14.5, then they decreased dramatically. HIF-1alpha mRNA expressed at high level from E13.5 to E15.5, and then decreased to low level.

CONCLUSIONFetal long bone development pattern appeared to be endochondral osteogenisis process, existing hypoxia microenviroment may increase HIF-1alpha mRNA expression and thus initiate the cascade of endochondral osteogenisis.

Animals ; Bone Development ; Female ; Hypoxia-Inducible Factor 1, alpha Subunit ; analysis ; genetics ; physiology ; Immunohistochemistry ; Male ; Mice ; RNA, Messenger ; analysis

BACKGROUNDAccumulating evidence demonstrates that the microenvironment of the host has an important effect on the chemoresistance of tumors. We also found that the formation of intrinsic multidrug resistance is related to environmental factors that are common with tumor growth of hepatocellular carcinoma. The aim of this study was to explore the molecular mechanisms by which multidrug resistance of hepatocellular carcinoma is induced by the microenvironment. In particular, the regulation of nuclear transcription factor (hypoxia-inducible factor-1α, HIF-1α) activation in the process of multidrug resistance formation was investigated.

METHODSHepG2 cells were exposed to different microenvironmental conditions respectively, such as hypoxia, stimulation of glucose deprivation and transfection of plasmid PcDNA3/HBx. In the HepG2 cells, the expression of the related MDR proteins, HIF-1α protein expression and localization, activity of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) were detected. Specific inhibitor U0126 was used to block ERK/MAPK signal pathway, the alteration of HIF-1α and the related MDR proteins were investigated. Multivariate analysis of variance (MANOVA) repeated measures and one-way analysis of variance (ANOVA) followed by Tukey test or t-test were used to determine differences over time and effects of the treatments.

RESULTSThe above three microenvironment factors increase the expression of the related MDR proteins (including P-gp, LRP, and MRP1) and induce MDR of HepG2 cells. HIF-1α was induced at the protein and mRNA levels and the nuclear translocation was also increased. The activity of ERK/MAPK was also increased in HepG2 cells. But when ERK/MAPK pathway was inhibited, the mRNA and protein expression of MDR1, MRP1, and LRP was to some extent decreased. Inhibition of ERK/MAPK significantly reduced activated HIF-1α protein and the nuclear translocation of HIF-1α, whereas HIF-1α mRNA levels were not affected.

CONCLUSIONSThe microenvironmental factors could induce MDR of HepG2 cells by the activity of HIF-1α. The activity of HIF-1α is regulated by the ERK/MAPK pathway at the phosphorylation level. As an important nuclear transcription factor, HIF-1α controls the transcription of MDR-related genes and the synthesis of their corresponding proteins by ERK/MAPK signal pathway in HepG2 cells.

Drug Resistance, Neoplasm ; Hep G2 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; physiology ; MAP Kinase Signaling System ; Tumor Microenvironment

The present study was aimed to investigate the effect of different altitudes on telomere length of rat peripheral blood leukocyte and possible mechanism. Sixty male rats were randomly divided into three groups, lower altitude control group (10 m), moderate altitude group (2 260 m) and very high altitude group (simulated 5 000 m). The moderate altitude group and very high altitude group rats were transported to Xining and hypobaric chamber in Qinghai University, respectively. The peripheral blood specimens were extracted 30 d after the transportation. By means of real-time PCR, automatic blood cell analyzer, ELISA, TBA and WST-1 methods, the telomere lengths of blood leukocyte, the hemoglobin (Hb) contents, the plasma levels of telomerase reverse transcriptase (TERT) and hypoxia-inducible factor 1α (HIF-1α), the plasma content of malondialdehyde (MDA) and superoxide dismutase (SOD) activity were measured, respectively. The results showed that the telomere lengths of peripheral blood leukocyte in moderate altitude group were longer than those in control group and very high altitude group. The changes of TERT were compatible with the telomere length of peripheral blood leukocyte under different altitudes. The levels of HIF-1α in moderate altitude group and very high altitude group were higher than that of control group. The very high altitude group showed decreased SOD activities and increased level of MDA, compared with the other two groups. These results suggest that the telomere lengths of rat peripheral blood leukocyte in moderate altitude are elongated, and that the telomere-elongating effect is lost under very high altitude. The changes of HIF-1α, TERT and oxidative stress damage are the main mechanisms of telomere length changes. Moderate altitude living might be beneficial to increasing the life span in mammals.
Altitude ; Animals ; Hemoglobins ; metabolism ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit ; blood ; Leukocytes ; physiology ; Male ; Malondialdehyde ; blood ; Oxidative Stress ; Rats ; Superoxide Dismutase ; metabolism ; Telomerase ; blood ; Telomere ; physiology