The present study was aimed at investigating the adverse effects of dietary zearalenone (ZEA) (1.1 to 3.2 mg/kg diet) on serum hormones, morphologic and apoptotic measurements of genital organs in post-weaning gilts. A total of twenty gilts (Landrace×Yorkshire×Duroc) weaned at 21 d with an average body weight of 10.36±1.21 kg were used in the study. Gilts were fed a basal diet with an addition of 0, 1.1, 2.0, or 3.2 mg/kg purified ZEA for 18 d ad libitum. Results showed that 3.2 mg/kg ZEA challenged gilts decreased (p<0.05) the serum levels of luteinizing hormone, however, serum levels of prolactin in gilts fed the diet containing 2.0 mg/kg ZEA or more were increased (p<0.05) compared to those in the control. Linear effects on all tested serum hormones except progesterone were observed as dietary ZEA levels increased (p<0.05). Gilts fed ZEA-contaminated diet showed increase (p<0.05) in genital organs size, hyperplasia of submucosal smooth muscles in the corpus uteri in a dose-dependent manner. However, the decreased numbers of follicles in the cortex and apoptotic cells in the ovarian were observed in gilts treated with ZEA in a dose-dependent manner. Degeneration and structural abnormalities of genital organs tissues were also observed in the gilts fed diet containing 1.1 mg/kg ZEA or more. Results suggested that dietary ZEA at 1.1 to 3.2 mg/kg can induce endocrine disturbance and damage genital organs in post-weaning gilts.
Zearalenone; Gilt; Hormones; Morphology; Apoptosis
The nonsense-mediated mRNA decay (NMD) pathway was originally discovered by virtue of its ability to rapidly degrade aberrant mRNAs with premature termination codons. More recently, it was shown that NMD also directly regulates subsets of normal transcripts, suggesting that NMD has roles in normal biological processes. Indeed, several NMD factors have been shown to regulate neurological events (for example, neurogenesis and synaptic plasticity) in numerous vertebrate species. In man, mutations in the NMD factor gene UPF3B, which disrupts a branch of the NMD pathway, cause various forms of intellectual disability (ID). Using Epstein Barr virus—immortalized B cells, also known as lymphoblastoid cell lines (LCLs), from ID patients that have loss-of-function mutations in UPF3B, we investigated the genome-wide consequences of compromised NMD and the role of NMD in neuronal development and function. We found that ~5% of the human transcriptome is impacted in UPF3B patients. The UPF3B paralog, UPF3A, is stabilized in all UPF3B patients, and partially compensates for the loss of UPF3B function. Interestingly, UPF3A protein, but not mRNA, was stabilised in a quantitative manner that inversely correlated with the severity of patients’ phenotype. This suggested that the ability to stabilize the UPF3A protein is a crucial modifier of the neurological symptoms due to loss of UPF3B. We also identified ARHGAP24, which encodes a GTPase-activating protein, as a canonical target of NMD, and we provide evidence that deregulation of this gene inhibits axon and dendrite outgrowth and branching. Our results demonstrate that the UPF3B-dependent NMD pathway is a major regulator of the transcriptome and that its targets have important roles in neuronal cells.
intellectual disability; Nonsense-mediated mRNA decay; RNA-SEQ; UPF3A; UPF3B
Oxidative stress is believed to be an important inducer of cellular senescence and aging. Zinc finger protein 637 (Zfp637), which belongs to the Krüppel-like protein family, has been hypothesized to play a role in oxidative stress. Nevertheless, the precise function of Zfp637 has seldom been reported, and it remains unclear whether Zfp637 is involved in oxidative stress-induced premature senescence. In this study, we show that the endogenous expression levels of Zfp637 and mouse telomerase reverse transcriptase (mTERT) are downregulated during oxidative stress-induced premature senescence and in senescent tissues from naturally aged mice. The overexpression of Zfp637 markedly increases mTERT expression and telomerase activity, maintains telomere length, and inhibits both H2O2 and D-galactose-induced senescence accompanied by a reduction in the production of reactive oxygen species (ROS). In contrast, the knockdown of Zfp637 significantly aggravates cellular senescence by downregulating mTERT and telomerase activity, accelerating telomere shortening, and increasing ROS accumulation. In addition, the protective effect of Zfp637 against premature senescence is abrogated in the absence of mTERT. We further confirm that Zfp637 binds to and transactivates the mTERT promoter (−535/−502) specifically. As a result, the mTERT-mediated telomerase activity and telomere maintenance are responsible for the protective effect of Zfp637 against oxidative stress-induced senescence. We therefore propose that Zfp637 prevents oxidative stress-induced premature senescence in an mTERT-dependent manner, and these results provide a new foundation for the investigation of cellular senescence and aging.
Public health research and interventions often assume that men who have sex with men (MSM) who use the Internet in China have similar characteristics to those in Western countries, though with little empirical evidence. This study aimed to describe and examine the sociodemographic and basic sexual behavioral characteristics of an online sample of MSM in Guangdong, China. In 2010, a total of 1100 MSM were recruited from an lesbian, gay, bisexual, and transgender (LGBT)-oriented website and were asked about their sociodemographic and sexual behavior characteristics. The majority of the participants (77.9%) self-identified as homosexual, and the mean age was 30.0 years (SD = 6.7). About 80% of the participants had attained a college degree and only 4.8% were unemployed. About 60% had a monthly salary of more than CNY 3000 (476 USD), and more than 10% were married. The majority (71.7%) had used condoms in the last anal sex. Nearly half of the participants have never been tested for HIV or other sexually transmitted infections (STIs) (47.3% and 47.7%, respectively). More than 80% were willing to be contacted by researchers after the survey. Findings indicate that the sociodemographic characteristics of Chinese MSM who use the Internet are relatively similar to those in the Western countries. However, Chinese MSM are less likely to self-identify as homosexual and be tested for HIV and other STIs than Western MSM. On a positive note, Chinese MSM would be likely to engage in e-technology research showing potential feasibility of an online HIV/STI intervention.
Chinese MSM; Internet; intervention; demographics; HIV testing
Activity of cortical local neuronal populations fluctuates continuously, and a large proportion of these fluctuations are shared across populations of neurons. Here we seek organizational rules that link these two phenomena. Using neuronal activity, as identified by functional MRI (fMRI) and for a given voxel or brain region, we derive a single measure of full bandwidth brain-oxygenation-level-dependent (BOLD) fluctuations by calculating the slope, α, for the log-linear power spectrum. For the same voxel or region, we also measure the temporal coherence of its fluctuations to other voxels or regions, based on exceeding a given threshold, Θ, for zero lag correlation, establishing functional connectivity between pairs of neuronal populations. From resting state fMRI, we calculated whole-brain group-averaged maps for α and for functional connectivity. Both maps showed similar spatial organization, with a correlation coefficient of 0.75 between the two parameters across all brain voxels, as well as variability with hodology. A computational model replicated the main results, suggesting that synaptic low-pass filtering can account for these interrelationships. We also investigated the relationship between α and structural connectivity, as determined by diffusion tensor imaging-based tractography. We observe that the correlation between α and connectivity depends on attentional state; specifically, α correlated more highly to structural connectivity during rest than while attending to a task. Overall, these results provide global rules for the dynamics between frequency characteristics of local brain activity and the architecture of underlying brain networks.
BOLD fMRI; power spectrum; connectivity; hodology; DTI tractography
Cryptococcal infection occurs in HIV-seropositive patients and is associated with high mortality. However, limited information is available on the prevalence and outcomes of cryptococcal antigenemia among hospitalized HIV-seropositive patients in sub-Saharan Africa.
To determine the prevalence of and risk factors for cryptococcal antigenemia among HIV-seropositive patients presenting to Mulago Hospital (Kampala, Uganda) with unexplained cough ≥2 weeks and suspected TB, and also to determine if antigenemia is associated with an increased mortality.
Between September 2009 and September 2010, we enrolled consecutive HIV-seropositive adults hospitalized at Mulago Hospital with cough ≥2 weeks and suspected TB. Banked serum was tested for cryptococcal antigen. We compared demographic, clinical characteristics and 2-month mortality in patients with and without cryptococcal antigenemia.
Of 563 HIV-seropositive patients, 32 (5.7%) were CrAg-positive. None had Cryptococcus neoformans detected on fungal culture of BAL fluid (n=116). CrAg-positive patients had a lower median CD4-count compared to CrAg-negative patients (25 vs. 55 cells/uL, p=0.02) and a substantial proportion of CrAg-positive patients also had concurrent TB (31%). A positive CrAg test was not associated with increased mortality during the 2-month follow-up period (HR: 0.99, 95% CI: 0.63–1.54, p=0.95) after adjusting for CD4 count and ART use at enrollment and/or follow-up.
Occult cryptococcal antigenemia occurs commonly among hospitalized HIV-seropositive patients with suspected TB. CrAg testing should be considered in hospitalized, HIV-seropositive patients with CD4 count <50 cells/uL, coupled with longer follow-up to evaluate the diagnostic value of CrAg and therapeutic interventions in patients with asymptomatic cryptococcal antigenemia.
Cryptococcus neoformans; antigenemia; tuberculosis; HIV; AIDS
Dicer is crucial for the maturation of microRNAs (miRNAs) and its dysregulation may contribute to tumor initiation and progression. The study explored the clinical implications of Dicer and its post-transcriptional regulation by microRNAs in cervical cancer. qRT-PCR and immunohistochemistry investigated Dicer mRNA and protein levels in cervical cancer tissues. The relationship between Dicer expression and survival was analyzed. MiRNA target prediction identified miRNAs that might target Dicer. Luciferase reporter and gain- or loss-of-function assays were performed. The results showed that 36.7% of cervical cancer cases showed low expression of Dicer mRNA and 63.3% cases showed high expression. At the protein level, 51% cases showed negative expression and 49% cases showed positive expression. Dicer mRNA and protein expressions were significantly associated with distant metastasis and recurrence in cervical cancer (P=0.002 and P=0.012, respectively). Multivariate Cox analysis indicated that low Dicer expression (P=0.016) and tumor stage (P=0.047) were independent predictors. Among the miRNAs predicted to target Dicer, 10 were detected by RT-PCR; their expressions were significantly higher in cervical cancers with lower Dicer expression than in those with higher Dicer expression and were negatively correlated with Dicer expression level (P<0.05). In vitro experiments demonstrated that miR-130a directly targeted Dicer mRNA to enhance migration and invasion in SiHa cells. Finally, survival analysis indicated that higher expression of miR-130a was significantly associated with poor disease-free survival. Taken together, Dicer expression regulated by miR-130a is an important potential prognostic factor in cervical cancer.
Dicer; miR-130; cervical cancer; microRNA; prognostic factor
Hypertrophy is a major predictor of progressive heart disease and has an adverse
prognosis. MicroRNAs (miRNAs) that accumulate during the course of cardiac
hypertrophy may participate in the process. However, the nature of any interaction
between a hypertrophy-specific signaling pathway and aberrant expression of miRNAs
remains unclear. In this study, Spague Dawley male rats were treated with transverse
aortic constriction (TAC) surgery to mimic pathological hypertrophy. Hearts were
isolated from TAC and sham operated rats (n=5 for each group at 5, 10, 15, and 20
days after surgery) for miRNA microarray assay. The miRNAs dysexpressed during
hypertrophy were further analyzed using a combination of bioinformatics algorithms in
order to predict possible targets. Increased expression of the target genes
identified in diverse signaling pathways was also analyzed. Two sets of miRNAs were
identified, showing different expression patterns during hypertrophy. Bioinformatics
analysis suggested the miRNAs may regulate multiple hypertrophy-specific signaling
pathways by targeting the member genes and the interaction of miRNA and mRNA might
form a network that leads to cardiac hypertrophy. In addition, the multifold changes
in several miRNAs suggested that upregulation of rno-miR-331*, rno-miR-3596b,
rno-miR-3557-5p and downregulation of rno-miR-10a, miR-221, miR-190, miR-451 could be
seen as biomarkers of prognosis in clinical therapy of heart failure. This study
described, for the first time, a potential mechanism of cardiac hypertrophy involving
multiple signaling pathways that control up- and downregulation of miRNAs. It
represents a first step in the systematic discovery of miRNA function in
Cardiac hypertrophy; Signaling pathway; Biomarker
Survivin is the smallest member of the inhibitor of apoptosis protein (IAP) family and acts as a bifunctional protein involved in mitosis regulation and apoptosis inhibition. To identify the physiological role of Survivin in female reproduction, we selectively disrupted Survivin expression in oocytes and granulosa cells (GCs), two major cell types in the ovary, by two different Cre-Loxp conditional knockout systems, and found that both led to defective female fertility. Survivin deletion in oocytes did not affect oocyte growth, viability and ovulation, but caused tetraploid egg production and thus female infertility. Further exploration revealed that Survivin was essential for regulating proper meiotic spindle organization, spindle assembly checkpoint activity, timely metaphase-to-anaphase transition and cytokinesis. Mutant mice with Survivin depleted in GCs showed reduced ovulation and subfertility, caused by defective follicular growth, increased follicular atresia and impaired luteinization. These findings suggest that Survivin has an important role in regulating folliculogenesis and oogenesis in the adult mouse ovary.
folliculogenesis; apoptosis; granulosa cell; meiosis; oocyte; Survivin
Mortalin (mot-2) induces inactivation of the tumor suppressor p53's transcriptional and apoptotic functions by cytoplasmic sequestration of p53 in select cancers. The mot-2-dependent cytoprotective function enables cancer cells to support malignant transformation. Abrogating the p53-mot-2 interaction can control or slow down the growth of cancer cells. In this study, we report the discovery of a ubiquitin-like (UBX)-domain-containing protein, UBXN2A, which binds to mot-2 and consequently inhibits the binding between mot-2 and p53. Genetic analysis showed that UBXN2A binds to mot-2's substrate binding domain, and it partly overlaps p53's binding site indicating UBXN2A and p53 likely bind to mot-2 competitively. By binding to mot-2, UBXN2A releases p53 from cytosolic sequestration, rescuing the tumor suppressor functions of p53. Biochemical analysis and functional assays showed that the overexpression of UBXN2A and the functional consequences of unsequestered p53 trigger p53-dependent apoptosis. Cells expressing shRNA against UBXN2A showed the opposite effect of that seen with UBXN2A overexpression. The expression of UBXN2A and its apoptotic effects were not observed in normal colonic epithelial cells and p53−/− colon cancer cells. Finally, significant reduction in tumor volume in a xenograft mouse model in response to UBXN2A expression was verified in vivo. Our results introduce UBXN2A as a home defense response protein, which can reconstitute inactive p53-dependent apoptotic pathways. Inhibition of mot-2-p53 interaction by UBXN2A is an attractive therapeutic strategy in mot-2-elevated tumors.
mot-2; p53; UBXN2A; colorectal cancer; apoptosis; xenograft
Photodynamic inactivation of pathogenic bacteria and cancer cells by novel water-soluble decacationic fullerene monoadducts, C60[>M(C3N6+C3)2] and C70[>M(C3N6+C3)2], were investigated. In the presence of a high number of electron-donating iodide anions as parts of quaternary ammonium salts in the arm region, we found that C70[>M(C3N6+C3)2] produced more highly reactive HO• radical than C60[>M(C3N6+C3)2], in addition to singlet oxygen (1O2). This finding offers an explanation of the preferential killing of Gram-positive and Gram-negative bacteria by C60[>M(C3N6+C3)2] and C70[>M(C3N6+C3)2], respectively. The hypothesis is that 1O2 can diffuse more easily into porous cell walls of Gram-positive bacteria to reach sensitive sites, while the less permeable Gram-negative bacterial cell wall needs the more reactive HO• to cause real damage.
Excessive oxidative stress in pancreatic β cells, caused by glucose and fatty acids,
is associated with the pathogenesis of type 2 diabetes. Mogrosides have shown
antioxidant and antidiabetic activities in animal models of diabetes, but the
underlying mechanisms remain unclear. This study evaluated the antioxidant effect of
mogrosides on insulinoma cells under oxidative stress caused by palmitic acid, and
investigated the underlying molecular mechanisms. Mouse insulinoma NIT-1 cells were
cultured in medium containing 0.75 mM palmitic acid, mimicking oxidative stress. The
effects of 1 mM mogrosides were determined with the dichlorodihydrofluorescein
diacetate assay for intracellular reactive oxygen species (ROS) and FITC-Annexin V/PI
assay for cell apoptosis. Expression of glucose transporter-2 (GLUT2) and pyruvate
kinase was determined by semi-quantitative reverse-transcription polymerase chain
reaction. Palmitic acid significantly increased intracellular ROS concentration
2-fold (P<0.05), and decreased expression of GLUT2 (by 60%, P<0.05) and
pyruvate kinase (by 80%, P<0.05) mRNAs in NIT-1 cells. Compared with palmitic
acid, co-treatment with 1 mM mogrosides for 48 h significantly reduced intracellular
ROS concentration and restored mRNA expression levels of GLUT2 and pyruvate kinase.
However, mogrosides did not reverse palmitic acid-induced apoptosis in NIT-1 cells.
Our results indicate that mogrosides might exert their antioxidant effect by reducing
intracellular ROS and regulating expression of genes involved in glucose metabolism.
Further research is needed to achieve a better understanding of the signaling pathway
involved in the antioxidant effect of mogrosides.
Mogrosides; Insulin-secreting cells; Oxidative stress damage; Apoptosis
Our previous studies have shown that the inhibition of phosphatidylinositol 3-kinase (PI3K) or mTOR complex 1 can obviously promote the Coxsackievirus B3 (CVB3)-induced apoptosis of HeLa cells by regulating the expression of proapoptotic factors. To further illustrate it, Homo sapiens eIF4E-binding protein 1 (4EBP1), p70S6 kinase (p70S6K), Akt1 and Akt2 were transfected to HeLa cells, respectively. And then, we established the stable transfected cell lines. Next, after CVB3 infection, apoptosis in different groups was determined by flow cytometry; the expressions of Bim, Bax, caspase-9 and caspase-3 were examined by real-time fluorescence quantitative PCR and western blot analysis; the expression of CVB3 mRNA and viral capsid protein VP1 were also analyzed by real-time fluorescence quantitative PCR, western blot analysis and immunofluorescence, respectively. At the meantime, CVB3 replication was observed by transmission electron microscope. We found that CVB3-induced cytopathic effect and apoptosis in transfected groups were more obvious than that in controls. Unexpectedly, apoptosis rate in Akt1 group was higher than others at the early stage after viral infection and decreased with the viral-infected time increasing, which was opposite to other groups. Compared with controls, the expression of CVB3 mRNA was increased at 3, 6, 12 and 24 h postinfection (p. i.) in all groups. At the meantime, VP1 expression in 4EBP1 group was higher than control during the process of infection, while the expressions in the other groups were change dynamically. Moreover, overexpression of 4EBP1 did not affect the mRNA expressions of Bim, Bax, caspase-9 and caspase-3; while protein expressions of Bim and Bax were decreased, the self-cleavages of caspase-9 and caspase-3 were stimulated. Meanwhile, overexpression of p70S6K blocked the CVB3-induced Bim, Bax and caspase-9 expressions but promoted the self-cleavage of caspase-9. In the Akt1 group, it is noteworthy that the expressions of Bim protein were higher than controls at 3 and 6 h p. i. but lower at 24 h p. i., and the expression of Bax protein were higher at 6 and 24 h p. i., while their mRNA expressions were all decreased. Furthermore, overexpression of Akt1 stimulated the procaspase-9 and procaspase-3 expression but blocked their self-cleavages. Overexpression of Akt2, however, had little effect on Bim, Bax and caspase-3, while prevented caspase-9 from self-cleavage at the late stage of CVB3 infection. As stated above, our results demonstrated that overexpression of 4EBP1, p70S6K, Akt1 or Akt2 could promote the CVB3-induced apoptosis in diverse degree via different mediating ways in viral replication and proapoptotic factors in BcL-2 and caspase families. As 4EBP1, p70S6K and Akt are the important substrates of PI3K and mammalian target of rapamycin (mTOR), we further illustrated the role of PI3K/Akt/mTOR signaling pathway in the process of CVB3-induced apoptosis.
overexpression; 4EBP1; p70S6K; Akt; coxsackievirus b3; apoptosis
Karyopherin alpha 2 (KPNA2), a member of the karyopherin family, has a central role in nucleocytoplasmic transport and is overexpressed in many cancers. Our previous study identified KPNA2 as significantly upregulated in epithelial ovarian carcinoma (EOC), correlating with poor survival of patients. However, the precise mechanism of this effect remains unclear. The aim of the present study was to examine the role of KPNA2 in the proliferation and tumorigenicity of EOC cells, and its clinical significance in tumor progression. Real-time quantitative RT-PCR analysis revealed high expression levels of KPNA2 in 162 out of 191 (84.8%) fresh EOC tissues, which was significantly correlated with International Federation of Gynecology and Obstetrics (FIGO) stage, differentiation, histological type, recurrence, and prognosis of EOC patients. Our results showed that upregulation of KPNA2 expression significantly increased the proliferation and tumorigenicity of EOC cells (EFO-21 and SK-OV3) in vitro and in vivo, by promoting cell growth rate, foci formation, soft agar colony formation, and tumor formation in nude mice. By contrast, knockdown of KPNA2 effectively suppressed the proliferation and tumorigenicity of these EOC cells in vitro and in vivo. Our results also indicated that the molecular mechanisms of the effect of KPNA2 in EOC included promotion of G1/S cell cycle transition through upregulation of c-Myc, enhanced transcriptional activity of c-Myc, activation of Akt activity, suppression of FOXO3a activity, downregulation of cyclin-dependent kinase (CDK) inhibitor p21Cip1 and p27Kip1, and upregulation of CDK regulator cyclin D1. Our results show that KPNA2 has an important role in promoting proliferation and tumorigenicity of EOC, and may represent a novel prognostic biomarker and therapeutic target for this disease.
KPNA2; epithelial ovarian carcinoma; proliferation; tumorigenicity; c-Myc; FOXO3a
We describe chest radiograph (CXR) findings in a population with a high prevalence of human immunodeficiency virus (HIV) and tuberculosis (TB) in order to identify radiological features associated with TB; to compare CXR features between HIV-seronegative and HIV-seropositive patients with TB; and to correlate CXR findings with CD4 T-cell count.
Consecutive adult patients admitted to a national referral hospital with a cough of duration of 2 weeks or longer underwent diagnostic evaluation for TB and other pneumonias, including sputum examination and mycobacterial culture, bronchoscopy and CXR. Two radiologists blindly reviewed CXRs using a standardised interpretation form.
Smear or culture-positive TB was diagnosed in 214 of 403 (53%) patients. Median CD4+ T-cell count was 50 cells mm–3 [interquartile range (IQR) 14–150]. TB patients were less likely than non-TB patients to have a normal CXR (12% vs 20%, p=0.04), and more likely than non-TB patients to have a diffuse pattern of opacities (75% vs 60%, p=0.003), reticulonodular opacities (45% vs 12%, p<0.001), nodules (14% vs 6%, p=0.008) or cavities (18% vs 7%, p=0.001). HIV-seronegative TB patients more often had consolidation (70% vs 42%, p=0.007) and cavities (48% vs 13%, p<0.001) than HIV-seropositive TB patients. TB patients with a CD4+ T-cell count of ≤50 cells mm–3 less often had consolidation (33% vs 54%, p=0.006) and more often had hilar lymphadenopathy (30% vs 16%, p=0.03) compared with patients with CD4 51–200 cells mm–3.
Although different CXR patterns can be seen in TB and non-TB pneumonias there is considerable overlap in features, especially among HIV-seropositive and severely immunosuppressed patients. Providing clinical and immunological information to the radiologist might improve the accuracy of radiographic diagnosis of TB.
The effects of acute responsive high frequency stimulation (HFS) to the subiculum on seizures and interictal spikes were investigated in a semi-acute kainic acid (KA) induced seizure model in rats. Wistar rats (n = 15) were implanted with an electrode-cannula complex in the CA3 area, stimulation and recording electrodes in the subiculum and another recording electrode at the contralateral motor cortex. Two weeks later rats were injected repeatedly with KA (0.05 μg/0.1 μL) for 3 days with an interval of 48 h. HFS (125 Hz, 100 μsec) was delivered to the subiculum at a predetermined intensity range (100–500 μA) in the HFS group (n = 7) when seizures were visually detected, while no stimulation was delivered in the sham control group (n = 8). Various severities of seizures were obtained (Stage I–V) and all rats of both groups reached Stage V (Racine's scale) on Day 1. The HFS group had less focal seizures and a longer inter-focal seizure interval on Day 1. Interictal spike rate was also lower in the HFS group and decreased with injection days. Significant day effects were found for the latency, number of focal seizures, and duration of focal seizures and generalized seizures while differences between groups were no longer present. Responsive HFS did not disrupt ongoing seizures. However, focal seizures and interictal spikes were suppressed by HFS. Such anticonvulsant effects of acute subicular stimulation indicate that the subiculum is involved in seizure generation. The reduction of seizure sensitivity over the injection day reflects an intrinsic anticonvulsant mechanism.
High frequency stimulation; responsive; stimulation; subiculum; temporal lobe epilepsy
Tumor hypoxia is correlated with genetic alteration and malignant progression. Our previous studies indicated that the hypoxia-inducible transcription factor, HIF-1α, is responsible for hypoxic suppression of DNA repair in tumor cells by a non-canonical mode of action that requires the HIF-1α PAS-B subdomain. The involvement of HIF-1α in genetic alteration has raised an intriguing question as to whether normal cells would respond to hypoxic stress differently to avert genetic alteration. In this study, we chose several mouse cell types ranging from benign to malignant, apoptosis-proficient to apoptosis-deficient, and determined their responses to HIF-1α expression. In agreement with our previous findings, transient hypoxia and HIF-1α expression inhibited DNA repair and induced DNA damage in all cell types examined; however, cumulative DNA damage only occurred in apoptosis-deficient, malignant cells transduced for sustained expression of HIF-1α or HIF-1α PAS-B itself. In keeping with the theory of apoptosis as a cancer barrier, only these apoptosis-deficient cells acquired anchorage-independent growth and epithelial-mesenchymal transition. Furthermore, these cells exhibited increased Akt activity and resistance to etoposide by inhibiting autophagy. Altogether, our results define an essential role for apoptosis to prevent HIF-1α-induced genetic alteration and thereby malignant progression.
apoptosis; autophagy; genetic alteration; hypoxia; tumor progression
Brown coat colour has been described in Chinese-Tibetan, Kele, and Dahe pigs. Here, we report the identification of a causal mutation underlying the brown colouration. We performed a genome-wide association study (GWAS) on Tibetan and Kele pigs, and found that brown colours in Chinese breeds are controlled by a single locus on pig chromosome 1. By using a haplotype-sharing analysis, we refined the critical region to a 1.5-Mb interval that encompasses only one pigmentation gene: tyrosinase-related protein 1 (TYRP1). Mutation screens of sequence variants in the coding region of TYRP1 revealed a strong candidate causative mutation (c.1484_1489del). The protein-altering deletion showed complete association with the brown colouration across Chinese-Tibetan, Kele, and Dahe breeds by occurring exclusively in brown pigs (n=121) and lacking in all non-brown-coated pigs (n=745) from 27 different breeds. The findings provide the compelling evidence that brown colours in Chinese indigenous pigs are caused by the same ancestral mutation in TYRP1. To our knowledge, this study gives the first description of GWAS identifying causal mutation for a monogenic trait in the domestic pig.
causal mutation; coat colour; genome-wide association; pig; TYRP1
Hypoxia is known to favor tumor survival and progression. Numerous studies have shown that hypoxia-inducible factor 1α (HIF-1α), an oxygen-sensitive transcription factor, is overexpressed in various types of human cancers and upregulates a battery of hypoxia-responsive genes for the growth and survival of cancer cells. Although tumor progression involves the acquisition of genetic and/or epigenetic changes that confer additional malignant traits, the underlying mechanisms of these changes remain obscure. We recently identified an alternative mechanism of HIF-1α function by which HIF-1α suppresses DNA repair by counteracting c-Myc transcriptional activity that maintains gene expression. Here we demonstrate that this HIF-α–c-Myc pathway plays an essential role in mediating hypoxic effects on malignant progression via genetic alterations, resulting in formation of malignant tumors with aggressive local invasion and epithelial–mesenchymal transition. We show an absolute requirement of the HIF-α–c-Myc pathway for malignant progression, whereas the canonical transcription function of HIF-1α alone is insufficient and seemingly dispensable. This study indicates that HIF-1α induction of genetic alteration is the underlying cause of tumor progression especially by the hypoxic microenvironment.
epithelial–mesenchymal transition; genetic alteration; hypoxia; tumorigenicity; tumor progression
Domestication, modern breeding and artificial selection have shaped dramatically the genomic variability of domestic animals. In livestock, the so-called FAT1 quantitative trait locus (QTL) in porcine chromosome 4 was the first QTL uncovered although, to date, its precise molecular nature has remained elusive. Here, we characterize the nucleotide variability of 13 fragments of ∼500 bp equally spaced in a 2 Mb region in the vicinity of the FAT1 region in a wide-diversity panel of 32 pigs. Asian and European animals, including local Mediterranean and international pig breeds, were sequenced. Patterns of genetic variability were very complex and varied largely across loci and populations; they did not reveal overall a clear signal of a selective sweep in any breed, although FABP4 fragment showed a significantly higher diversity. We used an approximate Bayesian computation approach to infer the evolutionary history of this SSC4 region. Notably, we found that European pig populations have a much lower effective size than their Asian counterparts: in the order of hundreds vs hundreds of thousands. We show also an important part of extant European variability is actually due to introgression of Asian germplasm into Europe. This study shows how a potential loss in diversity caused by bottlenecks and possible selective sweeps associated with domestication and artificial selection can be counterbalanced by migration, making it much more difficult the identification of selection footprints based on naive demographic assumptions. Given the small fragment analyzed here, it remains to be studied how these conclusions apply to the rest of the genome.
pig; quantitative trait locus; demographic history; Bayesian inference
This study describes a repeated measures prediction index to identify patients at high risk of ≥ grade 2 hand-foot skin reaction (HFSR) before each week of sorafenib therapy.
Data from 451 patients who received a sorafenib (400 mg bid) as part of a clinical trial were reviewed (Escudier B, Eisen T, Stadler WM et al. Sorafenib in advanced clear-cell renal-cell carcinoma. N Engl J Med 2007; 356: 125–134). Generalized estimating equations were used to develop the final risk model. A risk-scoring algorithm (range 0–58) was then derived from the final model coefficients. External validation was then carried out on a new sample of 1145 patients who received sorafenib under an expanded access program.
Pretreatment white blood cell count, female gender, good performance status, presence of lung and liver metastases and number of affected organs were predictors for ≥ grade 2 HFSR. A nonlinear association between HFSR risk and treatment duration was also identified where risk was maximized at week 5 followed by a gradual decline. Before each week of therapy, patients with risk scores >40 would be considered at high risk for developing ≥ grade 2 HFSR.
The application and planned continued refinement of this prediction tool will be an important source of patient-specific risk information for the development of moderate to severe HFSR.
hand-foot skin reaction; prediction; renal cell carcinoma; risk; sorafenib
The physiological regulation of the red cell mass depends upon enhanced transcription of the erythropoietin (Epo) gene in response to hypoxia. Studies of Epo gene expression have been useful in investigating the mechanism by which cells and tissues sense hypoxia and respond with biologically appropriate alterations in gene expression. It is likely that oxygen sensing involves a heme protein in which cobalt and nickel can substitute for iron in the porphyrin ring. Indirect evidence suggests that the sensor is present in all cells and is a multi-subunit assembly containing an NAD(P)H oxidase capable of generating peroxide and reactive oxygen intermediates, which serve as signaling molecules. The up-regulation of Epo gene transcription by hypoxia is mediated by at least two known DNA-binding transcription factors, hypoxia-inducible factor 1 (HIF-1) and hepatic nuclear factor 4 (HNF-4), which bind to cognate response elements in a critical 3′ enhancer approximately 50 bp in length. HIF-1 binding is induced by hypoxia as well as by cobalt. The activation of HIF-1 by hypoxia depends upon the selective protection of its α subunit from ubiquitin-dependent proteolysis by means of a mechanism that involves redox chemistry and perhaps phosphorylation. HNF-4 is an orphan nuclear receptor that is constitutively expressed in kidney and liver and which cooperates with HIF-1 to give maximal hypoxic induction. In hypoxic cells, p300 or a related family member forms a macromolecular assembly with HIF-1 and HNF-4, enabling transduction from the Epo 3′ enhancer to the apparatus on the promoter responsible for the initiation of transcription.
erythropoietin; hypoxia; gene regulation; oxygen sensing; HIF-1; HNF-4; p300
Pneumocystis pneumonia (PcP) remains a significant cause of morbidity and mortality in immunocompromised persons, especially those with human immunodeficiency virus (HIV) infection. Pneumocystis colonization is described increasingly in a wide range of immunocompromised and immunocompetent populations and associations between Pneumocystis colonization and significant pulmonary diseases such as chronic obstructive pulmonary disease (COPD) have emerged. This mini-review summarizes recent advances in our clinical understanding of Pneumocystis and PcP, describes ongoing areas of clinical and translational research, and offers recommendations for future clinical research from researchers participating in the “First centenary of the Pneumocystis discovery”.
Pneumocystis; colonization; Pneumocystis pneumonia (PcP); human immunodeficiency virus (HIV); acquired immune deficiency syndrome (AIDS); Pneumocystis; infection; pneumocystose pulmonaire (PcP); virus de l’immunodéficience humaine (VIH); syndrome de l’immunodéficience acquise (SIDA)