BACKGROUND: Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far. METHODS: Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-β, or Ror-γ. RESULTS: Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-β, or Ror-γ) in testis, with alteration in the rhythm parameters. CONCLUSION These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.
ARNTL Transcription Factors/genetics* ; Acid Phosphatase ; Animals ; CLOCK Proteins/genetics* ; Circadian Rhythm/radiation effects* ; Epididymis/radiation effects* ; Gene Expression/radiation effects* ; Genitalia, Male/radiation effects* ; Glucosephosphate Dehydrogenase ; L-Iditol 2-Dehydrogenase ; L-Lactate Dehydrogenase ; Male ; Mice ; Mice, Inbred C57BL ; Models, Animal ; Nuclear Receptor Subfamily 1, Group F, Member 1/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 2/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 3/genetics* ; RNA, Messenger/genetics* ; Radiation Exposure ; Radiation, Ionizing ; Reproductive Physiological Phenomena/radiation effects* ; Sperm Motility/radiation effects* ; Spermatozoa/radiation effects* ; Testis/radiation effects*

The cyanobacterial circadian clock has three relatively independent parts: the input path, the core oscillator, and the output path. The core oscillator is composed of three clock proteins: KaiA, KaiB, and KaiC. The interactions among these three proteins generate a rhythmic signal and convey the input signals to the output signals to maintain the accuracy and stability of the oscillation of downstream signals. Based on the cyanobacterial circadian clock and the structure, function, and interaction of the clock proteins of the core oscillator, combining the recent results from our laboratory, this review summarized the recent progresses of the molecular mechanism of KaiA in regulating KaiC's enzymatic activity, mediating phase reset of the oscillator, and competing with CikA for the binding site of KaiB.
Bacterial Proteins ; genetics ; metabolism ; Circadian Clocks ; genetics ; Circadian Rhythm Signaling Peptides and Proteins ; metabolism ; Cyanobacteria ; genetics ; Enzyme Activation ; genetics

The release of hormones and the metabolism of human body are controlled by the circadian rhythm related to sleep-wake cycle. Growth hormone, prolactin, thyroid stimulating hormone, cortisol, glucose, and insulin-secretion rates fluctuate according to the sleep-wake cycle. In addition, sleep is related to the appetite regulation and carbohydrate and other energy metabolism. Hypocretin (orexin), an excitatory neuropeptide, regulates waking and diet intake, and the poor sleep increases diet intake. The short sleep duration increases one's body mass index and impairs the function of the endocrine and metabolism, causing increases in the risk of glucose intolerance and diabetes. The poor sleep quality and sleep disorders have similar impact on the metabolic function. In short, the sleep loss and the poor quality of sleep have a detrimental effect on the endocrine and energy metabolism. The improvement of sleep quality by the future research and appropriate clinical treatment would contribute to the decrease of the metabolic diseases such as diabetes.
Appetite Regulation ; Body Mass Index ; Circadian Rhythm ; Diet ; Energy Metabolism ; Glucose ; Glucose Intolerance ; Growth Hormone ; Human Body ; Hydrocortisone ; Intracellular Signaling Peptides and Proteins ; Metabolic Diseases ; Neuropeptides ; Prolactin ; Sleep Wake Disorders ; Thyrotropin ; Orexins

OBJECTIVE: IL-17-producing T cells (Th17 cells) have been identified as a distinct lineage of CD4+ T helper cells in mice. Since this discovery, many efforts have been made to investigate the characteristics and the role of human Th17 cells and the factors involved in their differentiation. This study was undertaken to assess the effects of cytokines and stimulatory conditions on the differentiation of human CD4+ T cells into Th17 cells. METHODS: Peripheral blood CD4+ T cells were isolated from healthy humans and then these cells were cultured with using various stimulatory conditions. The Th17 cells and regulatory T (Treg) cells were detected by flow cytometry (FACs). The related gene expressions of cytokines, transcription factors and chemokine receptors were determined by ELISA and RT-PCR. RESULTS: In the presence of inflammatory cytokines, TNFa and IL-1b, the human CD4+ T cells rapidly produced IL-17 in response to anti-CD3/anti-CD28 stimulation, whereas, with anti-CD3/anti-CD28 stimulation alone, the CD4+ T cells expressed low levels of IL-17. TNFa and IL-1b were also important inducers of IL-22 production. IL-6 and IL-23 up-regulated the RORgammat, CCR4 and CCR6 expressions in the human CD4+ T cells. In response to TGF-b and IL-2, the human CD4+ T cells were rapidly induced to express FoxP3, IL-10 and CCR7, as compared with anti-CD3/anti-CD28 stimulation alone. CONCLUSION: The effect of inflammatory cytokines on the differentiation of human Th17 cells may help us to understand their pathogenic role. Moreover, the differential expression of chemokine receptors and transcription factors of the subsets of CD4+ T cells with the different features of Th17 and Treg, may raise new issues concerning the pathogenesis of autoimmune inflammatory diseases.
Animals ; Cytokines ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Gene Expression ; Humans ; Interleukin-10 ; Interleukin-17 ; Interleukin-2 ; Interleukin-23 ; Interleukin-6 ; Interleukins ; Mice ; Nuclear Receptor Subfamily 1, Group F, Member 3 ; Receptors, Chemokine ; T-Lymphocytes ; T-Lymphocytes, Helper-Inducer ; T-Lymphocytes, Regulatory ; Th17 Cells ; Transcription Factors

OBJECTIVETo explore the role of Th17 cells, CD4⁺ CD25⁺ regulatory Treg cells (Treg) and its transcription factor RORγt and FoxP3 in the pathogenesis of children with Henoch-Schonlein purpura (HSP) so as to provide a new strategy for treatment of children with Henoch-Schonlein purpura by regulating the balance of Th17 and Treg cells.

METHODSForty children with Henoch-Schonlein purpura in acute phase admitted in our hospital from February 2012 to March 2013 were enrolled in this study, forty healthy children were simultaneously used as controls. The expression of RORγt mRNA and FoxP3 mRNA in peripheral blood mononuclear cells was detected by real-time PCR using SYBR Green I. The levels of IL-17A, TGF-β1, IL-2 and IL-6 in serum were measured by ABC-ELISA. The ratio of Th17 cells to Treg cells in peripheral blood T lymphocytes was detected by flow cytometry.

RESULTSThe levels of Th17 cells (2.75 ± 0.60%) and RORγt mRNA (1.11 ± 0.51) in HSP group were significantly higher than levels of Th17 cells (1.41 ± 0.29%) and RORγt mRNA (0.65 ± 0.24) (P < 0.01) in control group, but the levels of Treg cells (4.56 ± 1.26%) and FoxP3 mRNA (1.15 ± 0.45) in HSP group were lower than those of Treg cells (7.85 ± 1.97%) and FoxP3 mRNA (2.32 ± 1.1) (P < 0.01) in the control group. The relative levels of serum IL-17A, IL-6, TGF-β1 (40.40 ± 11.81 pg/ml, 75.38 ± 27.19 pg/ml, 309.41 ± 81.03 pg/ml) in the HSP group were significantly higher than those in the control group [IL-17A (20.32 ± 10.70 pg/ml), IL-6 (25.16 ± 8.31 pg/ml), TGF-β1 (236.34 ± 66.01 pg/ml)] (P < 0.01), but the level of serum IL-2 (25.60 ± 13.19 pg/ml) in the HSP group was lower than that (34.42 ± 11.69 pg/ml) in the control group (P < 0.01). The further detection demonstrated that in the children with acute HSP, the expression of Th17 cells positively correlated with RORγt mRNA, IL-17A and IL-6 with the correlation coefficients of 0.887, 0.938 and 0.934 (P < 0.01), respectively. The positive correlation was also shown between the Treg cells and FoxP3 mRNA, IL-2 with the correlation coefficients of 0.834 and 0.932 (P < 0.01), respectively.

CONCLUSIONThere are higher expression levels of Th17 cells, RORγt mRNA and IL-17A, and lower expression levels of Treg cells, FoxP3 mRNA of children with HSP in acute phase, which shows that Th17/Treg imbalance exists in children with HSP in acute phase. The levels of serum IL-6, TGF-β1 increase and the serum IL-2 decrease in children with HSP in acute phase, moreover, there are the positive correlations between the levels of Th17 cells and expression of IL-6, as well as the level of Treg cells and expression of IL-2 in children with HSP in acute phase.

Case-Control Studies ; Child ; Flow Cytometry ; Forkhead Transcription Factors ; metabolism ; Humans ; Interleukin-17 ; blood ; Interleukin-2 ; blood ; Interleukin-6 ; blood ; Leukocytes, Mononuclear ; Nuclear Receptor Subfamily 1, Group F, Member 3 ; metabolism ; Purpura, Schoenlein-Henoch ; immunology ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; T-Lymphocytes, Regulatory ; cytology ; Th17 Cells ; cytology ; Transforming Growth Factor beta1 ; blood

The circadian clock has been linked to female reproductive physiology and endocrine in mammals. Epidemiological studies of female shift workers have shown increased rates of abnormal reproduction and adverse pregnancy. But little is known how the circadian rhythms affect reproduction. The aim of the present study was to investigate the influences of circadian rhythms on estrous cycle in female mice using clock gene Rev-erb-α knock out (Rev-erb-α(-/-)) mice. To test the fertility of Rev-erb-α(-/-) mice, litter sizes were counted after mating with C57BL/6J male mice. HE staining was used to observe the change of follicle development. The number of embryos of Rev-erb-α(+/+) and Rev-erb-α(-/-) female mice was compared 1.5 d after mating with C57BL/6J male mice. Then Rev-erb-α(+/+) and Rev-erb-α(-/-) female mice were housed to adult, and daily vaginal lavage with 0.9% saline was used to monitor estrous cycle for at least 30 days. Quantity of various cells was counted on specified smears views after staining. We observed estrous cycles of Rev-erb-α(+/+) and Rev-erb-α(-/-) female mice using line plots and periodic spectrograms. The results showed that the Rev-erb-α(-/-) female mice were infertility, and the number of embryos of Rev-erb-α(-/-) females was less than that of Rev-erb-α(+/+) females. However, the follicle development of Rev-erb-α(-/-) female mice was normal. The estrous cycle of Rev-erb-α(-/-) female mice was 3.22 days longer than that of Rev-erb-α(+/+) female mice. The results suggest that loss of Rev-erb-α prolongs estrous cycle, which is probably one of the reasons for female mice infertility, and circadian rhythm is important for mammalian estrous cycle.
Animals ; Circadian Rhythm ; Estrous Cycle ; Female ; Fertility ; Litter Size ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Nuclear Receptor Subfamily 1, Group D, Member 1 ; genetics ; physiology ; Pregnancy

OBJECTIVETo investigate the relationship between genetic variantions of circadian clock genes and risk of breast cancer.

METHODSA case-control study including 406 breast cancer patients and 412 controls was conducted and genes Clock (rs2070062) and Per2 (rs2304672, rs2304669, rs934945) were genotyped by TaqMan real-time PCR. Unconditional logistic regression model was used to analyze the association between the genetic polymorphisms and breast cancer.

RESULTSIndividuals with the rs2304669-TT genotype showed significantly increased breast cancer risk with the OR of 2.33 when compared with the individuals with rs2304669-CC and CT genotypes (P = 0.001). In addition, the three haplotypes containing the risk T allele of rs2304669 were identified to be associated with increased breast cancer risk. However, it was found that rs2304672, rs2070062 and rs934945 polymorphisms were not related with breast cancer risk.

CONCLUSIONSThe locus rs2304669 on Per2 gene is associated with breast cancer risk. Genetic variation of circadian clock genes may increase the susceptibility to breast cancer. Therefore, it may become an important biomarker of susceptibility to breast cancer.

Adult ; Biomarkers, Tumor ; genetics ; Breast Neoplasms ; genetics ; CLOCK Proteins ; genetics ; Carcinoma, Ductal, Breast ; genetics ; Case-Control Studies ; Female ; Genetic Variation ; Humans ; Period Circadian Proteins ; genetics ; Polymorphism, Single Nucleotide ; Risk Factors

Objective: To investigate the correlation between CLOCK and BMAL1 genes and MEN2 medullary thyroid carcinoma (MTC). Methods: Thirteen cases with MEN2 MTC and thirteen cases with non-MEN2 MTC were selected who were treated in the Yantai Yuhuangding Hospital between January 2013 and September 2021. Clinical indicators such as blood calcitonin level, tumor diameter and metastatic lymph node of patients were collected. The expression differences of CLOCK and BMAL1 between MEN2 MTC and para-carcinoma tissue as well as between MEN2 MTC and non-MEN2 MTC were detected by immunohistochemistry and qPCR. The correlation between lymph node metastasis and CLOCK or BMAL1 expression was analyzed. Protein-protein interaction (PPI) network analysis combined with qPCR and correlation analysis was used to explore the expression regulation relationship between RET and circadian clock genes. The rhythm disorder of MEN2 cells was verified by lipopolysaccharide cell stimulation experiment after dexamethasone rhythm synchronization. Results: MEN2 MTC exhibited typical RET gene mutation. The mean blood calcitonin level, the tumor diameter and the number of metastatic lymph nodes of patients with MEN2 MTC were higher than those of patients with non-MEN2 MTC (t value was 2.76, 2.53, 2.26, all P<0.05). Immunohistochemical results showed that the expression levels of CLOCK and BMAL1 in MEN2 MTC were higher than those in non-MEN2 MTC, while negatively expressed in para-cancerous thyroid follicle. qPCR displayed that the expression of CLOCK gene in cancer tissues was higher than that in non-MEN2 MTC and para-cancerous tissues (t value was 2.68 and 2.86, all P<0.05); the expression of BMAL1 gene in MEN2 MTC was higher than that in non-MEN2 MTC and para-cancerous tissues (t value was 2.21 and 2.35, all P<0.05). Correlation analysis showed that the expression levels of CLOCK and BMAL1 genes were positively correlated with the number of lymph node metastases in patients with MEN2 MTC (r=0.65, P<0.001; r=0.52, P=0.005). PPI network analysis indicated that the expression of CLOCK gene was positively correlated with the abnormal expression of RET gene (r=0.96, P<0.001). With lipopolysaccharide to stimulate cultured cells in vitro after dexamethasone rhythm synchronization, the expressions of CLOCK and BMAL1 in MEN2 MTC cells (0.47±0.22 and 2.60±1.48) at 12 hours of synchronization were significantly lower than those in para-cancerous tissues (1.70±1.62 and 8.23±2.52), the difference was statistically significant(t=5.04, P=0.007; t=3.34, P=0.029). Conclusion: CLOCK and BMAL1 are correlated with the occurrence and development of MEN2 MTC, and may be potential targets for the development of new therapeutic strategies for MEN2 MTC.
ARNTL Transcription Factors/genetics* ; CLOCK Proteins/genetics* ; Calcitonin ; Carcinoma, Neuroendocrine/genetics* ; Dexamethasone ; Humans ; Lipopolysaccharides ; Lymphatic Metastasis ; Multiple Endocrine Neoplasia Type 2a/genetics* ; Thyroid Neoplasms/surgery*

The sleep-wake cycle displays a characteristic 24-hour periodicity, providing an opportunity to dissect the endogenous circadian clock through the study of aberrant behaviour. This article surveys the properties of circadian clocks, with emphasis on mammals. Information was obtained from searches of peer-reviewed literature in the PUBMED database. Features that are highlighted include the known molecular components of clocks, their entrainment by external time cues and the output pathways used by clocks to regulate metabolism and behaviour. A review of human circadian rhythm sleep disorders follows, including recent discoveries of their genetic basis. The article concludes with a discussion of future approaches to the study of human circadian biology and sleep-wake behaviour.
ARNTL Transcription Factors ; Animals ; Basic Helix-Loop-Helix Transcription Factors ; physiology ; CLOCK Proteins ; Circadian Rhythm ; genetics ; physiology ; Humans ; Neurons, Afferent ; physiology ; Neurons, Efferent ; physiology ; Polymorphism, Single Nucleotide ; Sleep Disorders, Circadian Rhythm ; genetics ; physiopathology ; Suprachiasmatic Nucleus ; cytology ; physiology ; Trans-Activators ; physiology

OBJECTIVETo study the effects of biological clock protein on circadian disorders in hypoxic-ischemic brain damage (HIBD) by examining levels of CLOCK and BMAL1 proteins in the pineal gland of neonatal rats.

METHODSSeventy-two 7-day-old Sprague-Dawley (SD) rats were randomly divided into sham-operated and HIBD groups. HIBD model was prepared according to the modified Levine method. Western blot analysis was used to measure the levels of CLOCK and BMAL1 in the pineal gland at 0, 2, 12, 24, 36 and 48 hours after operation.

RESULTSBoth CLOCK and BMAL levels in the pineal gland increased significantly 48 hours after HIBD compared with the sham-operated group (P<0.05). There were no significant differences in levels of CLOCK and BMAL proteins between the two groups at 0, 2, 12, 24 and 36 hours after operation (P>0.05).

CONCLUSIONSLevels of CLOCK and BMAL1 proteins in the pineal gland of rats increase significantly 48 hours after HIBD, suggesting that both CLOCK and BMAL1 may be involved the regulatory mechanism of circadian disorders in rats with HIBD.

ARNTL Transcription Factors ; analysis ; physiology ; Animals ; Animals, Newborn ; CLOCK Proteins ; analysis ; physiology ; Chronobiology Disorders ; etiology ; Female ; Hypoxia-Ischemia, Brain ; metabolism ; Male ; Pineal Gland ; chemistry ; Rats ; Rats, Sprague-Dawley ; Time Factors