The Combination of Methioninase and Ethionine Exploits Methionine Addiction to Selectively Eradicate Osteosarcoma Cells and Not Normal Cells and Synergistically Down-regulates the Expression of C-MYC

BACKGROUND/AIM

The fundamental and general hallmark of cancer cells, methionine addiction, termed the Hoffman effect, is due to overuse of methionine for highly-increased transmethylation reactions. In the present study, we tested if the combination efficacy of recombinant methioninase (rMETase) and a methionine analogue, ethionine, could eradicate osteosarcoma cells and down-regulate the expression of c-MYC.

MATERIALS AND METHODS

143B osteosarcoma cells and Hs27 normal human fibroblasts were tested. The efficacy of rMETase alone and ethionine, alone and in their combination, on cell viability was determined with the WST-8 assay on 143B cells and Hs27 cells. c-MYC expression was examined with western immunoblotting and compared in 143B cells treated with/without rMETase, ethionine, or the combination of both rMETase and ethionine.

RESULTS

143B cells were more sensitive to both rMETase and ethionine than Hs 27 cells, with the following IC50s: rMETase (143B: 0.22 U/ml; Hs27: 0.82 U/ml); ethionine (143B: 0.24 mg/ml; Hs27: 0.42 mg/ml). The combination of rMETase and ethionine synergistically eradicated 143B cells, lowering the IC50 for ethionine 14-fold compared to ethionine alone (p<0.001). In contrast, Hs27 fibroblasts were relatively resistant to the combination. The expression of c-MYC was significantly down-regulated only by the combination of rMETase and ethionine in 143B cells (p<0.001).

CONCLUSION

In the present study, we showed, for the first time, the synergistic combination efficacy of rMETase and ethionine on osteosarcoma cells in contrast to normal fibroblasts, which were relatively resistant. The combination of rMETase and ethionine down-regulated c-MYC expression in the cancer cells. The present results indicate the combination of rMETase and ethionine may reduce the malignancy of osteosarcoma cells and can be a potential future clinical strategy.

Uneven Expression of 20 Human Papillomavirus Genes Associated with Oropharyngeal Carcinoma

BACKGROUND

Human papillomavirus (HPV) is considered to be responsible for 95% of virus-related cancers in many organs. Oropharyngeal carcinoma (OC) is distinguished by the transformation of the healthy epithelium into precancerous cells.

AIM

The current study sought to examine the uneven gene expression of 20 genes among those scanned by microarray for oropharyngeal cancer patients.

MATERIALS AND METHODS

The GSE56142 dataset was extracted from the Gene Expression Omnibus of the National Center for Biotechnology Information; 24 specimens were evaluated. Gene ontology (GO), the Kyoto Encyclopedia of Genes and Genomes, and the protein-protein interaction (PPI) were used to depict the biological roles of the genes under investigation using types of software.

RESULTS

Six genes out of 20 in patients with invasive OC had a binding correlation with high expression (PDGFRS, COL6A3, COL1A1, COL3A1, COL2A1, and COL4A1), and only two genes with low expression (CRCT1 and KRT78). The expression levels of 20 genes were examined for patients with OC versus head and neck squamous cell carcinoma (HNSCC). The correlation coefficient between highly expressed genes of the OC group was statistically significant at the P<0.05 level.

CONCLUSIONS

High expression levels of specific genes may serve as diagnostic tumor markers, particularly in the early stages of cancer, and testing should be performed in OC and HNSCC patients.

Clinical Investigation of Chemotherapeutic Resistance and miRNA Expressions in Head and Neck Cancers: A Thorough PRISMA Compliant Systematic Review and Comprehensive Meta-Analysis

Background: Chemoresistance is a significant barrier to combating head and neck cancer, and decoding this resistance can widen the therapeutic application of such chemotherapeutic drugs. This systematic review and meta-analysis explores the influence of microRNA (miRNA) expressions on chemoresistance in head and neck cancers (HNC). The objective is to evaluate the theragnostic effects of microRNA expressions on chemoresistance in HNC patients and investigate the utility of miRNAs as biomarkers and avenues for new therapeutic targets. Methods: We performed a comprehensive bibliographic search that included the SCOPUS, PubMed, and Science Direct bibliographic databases. These searches conformed to a predefined set of search strategies. Following the PRISMA guidelines, inclusion and exclusion criteria were framed upon completing the literature search. The data items extracted were tabulated and collated in MS Excel. This spreadsheet was used to determine the effect size estimation for the theragnostic effects of miRNA expressions on chemoresistance in HNC, the hazard ratio (HR), and 95% confidence intervals (95% CI). The comprehensive meta-analysis was performed using the random effects model. Heterogeneity among the data collected was assessed using the Q test, Tau², I², and Z measures. Publication bias of the included studies was checked using the Egger's bias indicator test, Orwin and classic fail-safe N test, Begg and Mazumdar rank collection test, and Duval and Tweedie's trim and fill methods. Results: After collating the data from 23 studies, dysregulation of 34 miRNAs was observed in 2189 people. These data were gathered from 23 studies. Out of the 34 miRNAs considered, 22 were up-regulated, while 12 were down-regulated. The TaqMan transcription kits were the most used miRNA profiling platform, and miR-200c was seen to have a mixed dysregulation. We measured the overall pooled effect estimate of HR to be 1.516 for the various analyzed miRNA at a 95% confidence interval of 1.303-1.765, with a significant p-value. The null hypothesis test's Z value was 5.377, and the p-value was correspondingly noted to be less than 0.0001. This outcome indicates that the risk of death is determined to be higher in up-regulated groups than in down-regulated groups. Among the 34 miRNAs that were investigated, seven miRNAs were associated with an improved prognosis, especially with the overexpression of these seven miRNAs (miR15b-5p, miR-548b, miR-519d, miR-1278, miR-145, miR-200c, Hsa- miR139-3p). Discussion: The findings reveal that intricate relationships between miRNAs' expression and chemotherapeutic resistance in HNC are more likely to exist and can be potential therapeutic targets. This review suggests the involvement of specific miRNAs as predictors of chemoresistance and sensitivity in HNC. The examination of the current study results illustrates the significance of miRNA expression as a theragnostic biomarker in medical oncology.

Targeted Suppression of miRNA-33 Using pHLIP Improves Atherosclerosis Regression

BACKGROUND

miRNA therapeutics have gained attention during the past decade. These oligonucleotide treatments can modulate the expression of miRNAs in vivo and could be used to correct the imbalance of gene expression found in human diseases such as obesity, metabolic syndrome, and atherosclerosis. The in vivo efficacy of current anti-miRNA technologies hindered by physiological and cellular barriers to delivery into targeted cells and the nature of miRNAs that allows one to target an entire pathway that may lead to deleterious off-target effects. For these reasons, novel targeted delivery systems to inhibit miRNAs in specific tissues will be important for developing effective therapeutic strategies for numerous diseases including atherosclerosis.

METHODS

We used pH low-insertion peptide (pHLIP) constructs as vehicles to deliver microRNA-33-5p (miR-33) antisense oligonucleotides to atherosclerotic plaques. Immunohistochemistry and histology analysis was performed to assess the efficacy of miR-33 silencing in atherosclerotic lesions. We also assessed how miR-33 inhibition affects gene expression in monocytes/macrophages by single-cell RNA transcriptomics.

RESULTS

The anti-miR-33 conjugated pHLIP constructs are preferentially delivered to atherosclerotic plaque macrophages. The inhibition of miR-33 using pHLIP-directed macrophage targeting improves atherosclerosis regression by increasing collagen content and decreased lipid accumulation within vascular lesions. Single-cell RNA sequencing analysis revealed higher expression of fibrotic genes (Col2a1, Col3a1, Col1a2, Fn1, etc) and tissue inhibitor of metalloproteinase 3 (Timp3) and downregulation of Mmp12 in macrophages from atherosclerotic lesions targeted by pHLIP-anti-miR-33.

CONCLUSIONS

This study provides proof of principle for the application of pHLIP for treating advanced atherosclerosis via pharmacological inhibition of miR-33 in macrophages that avoid the deleterious effects in other metabolic tissues. This may open new therapeutic opportunities for atherosclerosis-associated cardiovascular diseases via selective delivery of other protective miRNAs.

Clinical Theragnostic Relationship between Chemotherapeutic Resistance, and Sensitivity and miRNA Expressions in Head and Neck Cancers: A Systematic Review and Meta-Analysis Protocol

Background: The microRNAs (miRNAs) are small noncoding single-stranded RNAs typically 19-25 nucleotides long and regulated by cellular and epigenetic factors. These miRNAs plays important part in several pathways necessary for cancer development, an altered miRNA expression can be oncogenic or tumor-suppressive. Recent experimental results on miRNA have illuminated a different perspective of the molecular pathogenesis of head and neck cancers. Regulation of miRNA can have a detrimental effect on the efficacy of chemotherapeutic drugs in both neoadjuvant and adjuvant settings. This miRNA-induced chemoresistance can influence the prognosis and survival rate. The focus of the study is on how regulations of various miRNA levels contribute to chemoresistance in head and neck cancer (HNC). Recent findings suggest that up or down-regulation of miRNAs may lead to resistance towards various chemotherapeutic drugs, which may influence the prognosis. Methods: Studies on miRNA-specific chemoresistance in HNC were collected through literary (bibliographic) databases, including SCOPUS, PubMed, Nature, Elsevier, etc., and were systematically reviewed following PRISMA-P guidelines (Preferred Reporting Items for Systematic Review and Meta-analysis Protocol). We evaluated various miRNAs, their up and downregulation, the effect of altered regulation on the patient's prognosis, resistant cell lines, etc. The data evaluated will be represented in the form of a review and meta-analysis. Discussion: This meta-analysis aims to explore the miRNA-induced chemoresistance in HNC and thus to aid further researches on this topic. PROSPERO registration: CRD42018104657.

The Impact of Down-Regulation on Obstetrics and Perinatal Outcomes in Singleton Pregnancies After In Vitro Fertilization

BACKGROUND

down-regulation has been widely used in IVF treatment; however, it lacks reports on the impact of down-regulation on obstetrics and perinatal outcomes. The purpose of this study was to compare the obstetrics and perinatal outcomes among different down-regulation conditions.

METHODS

this is a retrospective cohort study on 3578 patients achieving cumulative singleton clinical pregnancy after their first oocytes retrieval cycle. Patients were grouped according to the serum estradiol after down-regulation (E2D) into three groups: <30, 30-55, >55 pg/ml. The obstetrics and perinatal outcomes, and live-birth rate per clinical pregnancy were main outcome measures. In the subgroup analysis, patients were further divided according to the mode of transfer. ANOVA, chi-square test, multivariate logistic regression, and multivariate general linear model were performed for statistical analysis.

RESULTS

the patients with E2D <30, 30-55, >55 pg/ml had similar live-birth rates. The patients with E2D <30 pg/ml had a lower risk of hypertension disorders than those with E2D 30-55 pg/ml. No difference was found in the risks of placenta previa, placenta abruption, premature rupture of membrane, hemorrhage, gestational diabetes mellitus, or intrauterine growth restriction. The newborns in the group with E2D <30 pg/ml had a lower risk of PICU admission than those in the group with E2D >55 pg/ml. There was no difference in the risks of congenital anomalies or mortality among the three groups. No differences were found in the gestational week, percentages of preterm birth and very preterm birth, birth weight, percentages of low birth weight and very low birth weight, delivery mode, or sex of newborn. Subgroup analysis showed that E2D 30-55 pg/ml was associated with a higher risk of low birth weight in patients with one fresh transfer + frozen transfer(s).

CONCLUSION

Down-regulation has no effect on the live-birth rate per clinical pregnancy. Patients with E2D <30 pg/ml may have advantages regarding lower risks of both maternal hypertension and newborn PICU admission. E2D 30-55 pg/ml may be associated with low birth weight in patients with relatively low quality embryos.

Determination of expression profile of p53 gene in different grades of breast cancer tissues by real time PCR

Background

Pakistan has a high incidence of breast cancer in Asia, where annually 16,232 deaths are reported. There are many exogenous and endogenous risk factors that affect the tumor suppressor genes and oncogenes. The p53 gene is a tumor suppressor gene and it has a role to protect the whole genome from external and internal stresses, which causes damages to the genome.

Objective

The aim of the current study was to investigate the p53 gene expression by using the real-time PCR technique in different grades of breast cancer as compared to the normal tissue.

Methods

Fresh Modified Radical Mastectomy (MRM) samples (grade1-grade3) were collected from different hospitals of the Lahore. The project was approved by an ethical review committee of Jinnah Hospital, Lahore. And before sampling an informed consent was obtained from patients and clinicians. RNA from fresh biopsies was extracted by Qiagen extraction kit and cDNA was formed. Real time PCR performed by using SYBR green master mix (ABI) and the data was evaluated by using Livak method. Statistical analysis was done by using Microsoft Excel.

Results

There was an abnormal gene expression of p53 in all grades of the breast tumors. Non-significant (p>0.05) difference of down and up regulation of p53 in different grades of breast tumor was found. However, as a whole up-regulation was more than down-regulation with significant difference (p<0.0011).

Conclusion

The abnormal expression of p53 shows that there are some genetic and epigenetic factors which are the primal cause of an abnormal gene expression. It is recommended that perform next generation sequencing (NGS) of the gene to find out the mutations causing the abnormal behavior of p53 gene.

Differential expression of Scinderin and Gelsolin in gastric cancer and comparison with clinical and morphological characteristics

Gastric cancer is the first cause of cancer-related death in males and the second in female patients in Iran. Advanced cancer is usually associated with distant metastasis, which is uncontrollable. This study was conducted to compare the expression of Scinderin and Gelsolin genes between gastric cancer and adjacent normal tissue samples in Iranian patients in order to better understand the role of these genes in this disease and to assess them as potential gastric cancer diagnostic or prognostic biomarkers. This case-control study was conducted in 41 Iranian patients suffering from stage I to IV of Gastric Cancer diagnosed by pathologic and endoscopic tests. In this study, significant down-regulation of Gelsolin (p=0.001) and over-expression of Scinderin (p=0.001) were observed in tumor tissues compared to the adjacent normal tissues. The results of the present study showed decreased Gelsolin expression in patients above 40 years, while the relationship between Gelsolin expression and age was not significant; also, a significant increase was observed in Scinderin expression in patients above 40 years. Furthermore, Lymph node metastasis was observed in 59.52 % of the cases. The results showed that reduced Gelsolin and increased Scinderin expression were related to lymph node metastasis. Based on results, a significant association was observed between tumor size and Scinderin expression level. Furthermore, Gelsolin and Scinderin expressions were assessed in different grades and stages to determine the association of this gene with cancer progression. The result indicates significant alteration in Scinderin expression level of I and IV, II and IV, and III and IV stages. Although no significant association was observed between Scinderin expression level and GC grade, the mean Gelsolin expression showed a significant difference between grade II and III as well as grade I and IV. Based on our results, these genes would be potential biomarkers.

The Role of Pro-Inflammatory and Regulatory Signaling by IL-33 in the Brain and Liver: A Focused Systematic Review of Mouse and Human Data and Risk of Bias Assessment of the Literature

Interleukin (IL)-33 is a member of the IL-1 family of proteins that have multiple roles in organ-specific inflammation. Many studies suggest diagnostic and therapeutic implications of this cytokine. Many studies have reported pro-inflammatory roles for IL-33 in innate immune responses involving the heart and lung. Recent studies also describe pro-inflammatory and regulatory roles for IL-33 in the pathogenesis of brain and liver disorders in addition to regulatory roles for this cytokine in the heart and lung. In this focused systematic review, we will review the literature regarding pro-inflammatory and regulatory effects of IL-33 in the brain and liver. We will also assess the potential risk of bias in the published literature in order to uncover gaps in the knowledge that will be useful for the scientific community. We utilized guidelines set by preferred reporting items for systemic reviews and meta-analyses. The electronic database was PubMed. Eligibility criteria included organ-specific inflammation in mice and humans, organ-specific inflammation in the central nervous and hepatic systems, and IL-33. Outcomes were pro-inflammatory or regulatory effects of IL-33. Risk of bias in individual studies and across studies was addressed by adapting the Cochrane Rob 2.0 tool. We discovered that a source of bias across the studies was a lack of randomization in human studies. Additionally, because the majority of studies were performed in mice, this could be perceived as a potential risk of bias. Regarding the central nervous system, roles for IL-33 in the development and maturation of neuronal circuits were reported; however, exact mechanisms by which this occurred were not elucidated. IL-33 was produced by astrocytes and endothelial cells while IL-33 receptors were expressed by microglia and astrocytes, demonstrating that these cells are first responders for IL-33; however, in the CNS, IL-33 seems to induce Th1 cytokines such as IL-1β and TNF-α chemokines such as RANTES, MCP-1, MIP-1α, and IP-10, as well as nitric oxide. In the liver, similar risks of bias were determined because of the lack of randomized controlled trials in humans and because the majority of studies were performed in mice. Interestingly, the strain of mouse utilized in the study seemed to affect the role of IL-33 in liver inflammation. Lastly, similar to the brain, IL-33 appeared to have ST2-independent regulatory functions in the liver. Our results reveal plausible gaps in what is known regarding IL-33 in the pathogenesis of brain and liver disorders. We highlight key studies in the lung and heart as examples of advancements that likely occurred because of countless basic and translational studies in this area. More research is needed in these areas in order to assess the diagnostic or therapeutic potential of IL-33 in these disorders.

Novel Insights and New Developments Regarding Coagulation Revealed by Studies of the Anti-Factor IXa (Activated Factor IX)/Factor X Bispecific Antibody, Emicizumab

Emicizumab is a humanized anti-FIXa/FX (factor IXa/X) bispecific monoclonal antibody that mimics FVIIIa (activated factor VIII) cofactor function. The hemostatic efficacy of emicizumab has been confirmed in clinical studies of patients with hemophilia A, irrespective of the presence of FVIII inhibitors. Emicizumab differs in some properties from FVIIIa molecule. Emicizumab requires no activation by thrombin and is not inactivated by activated protein C, but emicizumab-mediated coagulation is regulatable and maintains hemostasis. A small amount of FIXa (activated factor IX) is required to initiate emicizumab-mediated hemostasis, whereas tissue factor/FVIIa (activated factor VII)-mediated FXa (activated factor X) and thrombin activation initiates FVIIIa-mediated hemostasis. Fibrin formation, followed by fibrinolysis, appears to be similar between emicizumab- and FVIIIa-mediated hemostasis. These results suggest possible future uses of emicizumab for treating hemorrhagic diseases other than hemophilia A and reveal previously unobservable behaviors of procoagulation and anticoagulation factors in conventional hemostasis. Here, we have reviewed novel insights and new developments regarding coagulation highlighted by emicizumab.

Endophytes alleviate the elevated CO2-dependent decrease in photosynthesis in rice, particularly under nitrogen limitation

The positive effects of high atmospheric CO2 concentrations [CO2] decrease over time in most C3 plants because of down-regulation of photosynthesis. A notable exception to this trend is plants hosting N-fixing bacteria. The decrease in photosynthetic capacity associated with an extended exposure to high [CO2] was therefore studied in non-nodulating rice that can establish endophytic interactions. Rice plants were inoculated with diazotrophic endophytes isolated from the Salicaceae and CO2 response curves of photosynthesis were determined in the absence or presence of endophytes at the panicle initiation stage. Non-inoculated plants grown under elevated [CO2] showed a down-regulation of photosynthesis compared to those grown under ambient [CO2]. In contrast, the endophyte-inoculated plants did not show a decrease in photosynthesis associated with high [CO2], and they exhibited higher photosynthetic electron transport and mesophyll conductance rates than non-inoculated plants under high [CO2]. The endophyte-dependent alleviation of decreases in photosynthesis under high [CO2] led to an increase in water-use efficiency. These effects were most pronounced when the N supply was limited. The results suggest that inoculation with N-fixing endophytes could be an effective means of improving plant growth under high [CO2] by alleviating N limitations.

Differential long-term regulation of TAS2R14 by structurally distinct agonists

Bitter taste receptor-14 (TAS2R14) is a GPCR also expressed on human airway smooth muscle cells, which signals to intracellular [Ca²⁺], resulting in relaxation of the airway, and is a novel target for bronchodilators. Here, we examine long-term, agonist-promoted down-regulation of TAS2R14 expression because tachyphylaxis would be an undesirable therapeutic characteristic. Five TAS2R structurally distinct full agonists were studied to ascertain biasing away from down-regulation. Agonist exposure for 18 h caused minimal desensitization by diphenhydramine (DPD) compared with ∼50% desensitization with all other agonists. Agonists evoked β-arrestin recruitment to TAS2R14, which was not seen with a phosphoacceptor-deficient mutant, TAS2R14-10A. All agonists except for DPD also caused subsequent TAS2R14 internalization and trafficking via early and late endosomes to down-regulation. TAS2R14-10A failed to undergo these events with any agonist. Molecular docking showed that DPD has specific interactions deep within a binding pocket that are not observed with the other agonists, which may lock the receptor in a conformation that does not internalize and therefore does not undergo down-regulation. Thus, TAS2R14 is subject to β-arrestin-mediated internalization and subsequent down-regulation with chronic exposure to most agonists. However, by manipulating the agonist structure, biasing toward G-protein coupling but away from long-term down-regulation can be achieved.-Woo, J. A., Castaño, M., Goss, A., Kim, D., Lewandowski, E. M., Chen, Y., Liggett, S. B. Differential long-term regulation of TAS2R14 by structurally distinct agonists.

Eyes-Closed Resting EEG Predicts the Learning of Alpha Down-Regulation in Neurofeedback Training

Neurofeedback training, which enables the trainee to learn self-control of the EEG activity of interest based on online feedback, has demonstrated benefits on cognitive and behavioral performance. Nevertheless, as a core mechanism of neurofeedback, learning of EEG regulation (i.e., EEG learning) has not been well understood. Moreover, a substantial number of non-learners who fail to achieve successful EEG learning have often been reported. This study investigated the EEG learning in alpha down-regulation neurofeedback, aiming to better understand the alpha learning and to early predict learner/non-learner. Twenty-nine participants received neurofeedback training to down-regulate alpha in two days, while eight of them were identified as non-learners who failed to reduce their alpha within sessions. Through a stepwise linear discriminant analysis, a prediction model was built based on participant's eyes-closed resting EEG activities in broad frequency bands including lower alpha, theta, sigma and beta 1 measured before training, which was validated in predicting learners/non-learners. The findings would assist in the early identification of the individuals who would not likely reduce their alpha during neurofeedback.

MicroRNA-200b expression level is negatively associated with pathological grading in human gliomas

Aim

To elucidate the clinical implication of microRNA (miRNA)-200b in the pathological grading of gliomas.

Methods

We searched the Chinese National Knowledge Infrastructure, Web of Knowledge, Embase, and PubMed databases. Related articles were assessed, and ORs with 95% CIs were calculated to examine the relationship between miRNA-200b expression levels and the World Health Organization (WHO) glioma grade, patients’ sex and age, tumor size, and extent of surgical resection. Heterogeneity, publication bias, and stability of the pooled results of the included studies were also analyzed. MiR-200b expression in 87 human glioma tissues (50 high grade and 37 low grade) and matched 41 non-neoplastic brain tissues was measured by real-time quantitative RT-PCR assay.

Results

Five eligible studies involving 630 patients were included in the present meta-analysis. The miRNA-200b expression in glioma tissues was negatively associated with the WHO glioma grade (OR, 0.070; 95% CI, 0.007–0.678; P=0.022). No significant correlations were found between miRNA-200b and sex (P=0.858), age (P=0.776), tumor size (P=0.134), or extent of resection (P=0.778). In our own test, compared with non-neoplastic brain tissues, the expression level of miR-200b was significantly decreased in glioma tissues (tumor vs normal: 4.29±1.90 vs 10.45±2.34, P<0.001). In addition, we found that the glioma tissues from high-grade tumors (grade III and IV) had much lower miR-200b expression than glioma tissues from low grade tumors (grade I and II).

Conclusion

Our results suggest that the miRNA-200 expression level may be negatively associated with the WHO glioma grade (malignancy). MiRNA-200 might serve as a prognostic and diagnostic biomarker or a helpful therapeutic target.

The rate of euploid miscarriage is increased in the setting of adenomyosis

STUDY QUESTION

Does the rate of miscarriage increase in the setting of adenomyosis independent of other known risk factors for miscarriage such as maternal age, BMI, embryo genetic status?

SUMMARY ANSWER

Adenomyosis and high BMI both significantly increase miscarriage risk independent of each other, maternal age and embryo health. This study is the first to suggest that ultra-long down regulation GnRH agonist treatment may reduce the rate of early pregnancy loss in adenomyosis patients.

WHAT IS KNOWN ALREADY

The presence of adenomyosis is known to be associated with lower rates of successful implantation and increased risk of early pregnancy loss. However, it is presently unclear whether this reproductive impairment is directly mediated by adenomyosis itself, or indirectly caused by adenomyosis association with known risk factors for miscarriage such as obesity and advancing maternal age/foetal aneuploidy.

STUDY DESIGN SIZE DURATION

A retrospective cohort study was undertaken in a private infertility (IVF) clinic examining the outcome for women (n = 345) undergoing the transfer of a genetically screened frozen-thawed embryo between 2012 and 2015.

PARTICIPANTS/MATERIALS SETTING AND METHOD

A total of 171 women who successfully conceived (positive serum βhCG) following the transfer of a single euploid good morphology frozen-thawed embryo were included in analysis after meeting the inclusion criteria. Only the first conception cycle for each patient was included in the study. Patients with known pre-existing medical risk factors for miscarriage (e.g. thrombophilia, poorly controlled diabetes, coeliac disease, SLE, uterine septum, chromosomal abnormalities) and those women undergoing treatment using donated oocytes and surrogacy were excluded. Patients were then classified as having adenomyosis or not based on a high-quality pelvic ultrasound or MRI. The direct and indirect effects of adenomyosis and BMI on overall miscarriage rate by 12 weeks gestation was then assessed using multivariate logistic regression and mediation analysis. Furthermore, the data were also analysed to elucidate the influence of GnRH ultra-long down-regulation therapy on miscarriage rates.

MAIN RESULTS AND ROLE OF CHANCE

Overall, the adjusted rate of miscarriage was higher in those patients with adenomyosis compared to those without (44.1 vs 15.3%, P < 0.0001), with most of these miscarriages occurring at the early biochemical stage. The rate of miscarriage was especially high in adenomyosis patients not receiving GnRH agonist pre-treatment (82.4%), compared to those patients who did receive GnRH pre-treatment (35.7%, P = 0.0089).

LIMITATIONS REASONS FOR CAUTION

The study is mainly limited by its small sample size and retrospective design which carries inherent potential for bias (i.e. misclassification and errors due to inadequate clinical notes). The small sample size precluded analysis to distinguish how the extent of adenomyosis disease may modify miscarriage risk (i.e. focal or diffuse disease). Furthermore, the relatively low number of adenomyosis patients not receiving GnRH agonist treatment, plus the non-randomized nature of the decision not to offer such treatment, precludes definitive conclusions on the benefit of GnRH agonist therapy to reduce miscarriage risk.

WIDER IMPLICATIONS OF THE FINDINGS

Considering the significant emotional and financial impact of miscarriage, we suggest screening of all women undergoing IVF treatment for the presence of adenomyosis, with consideration given to ultra-long down regulation GnRH agonist treatment in any woman identified as having adenomyosis. Furthermore, given the persistent and often progressive nature of the disease, adenomyosis should also be considered as a potential uterine cause of recurrent miscarriage. Finally, we hope our study highlights the need for high-quality prospective RCT to be undertaken to provide superior evidence for the potential benefit of GnRH agonist pre-treatment.

STUDY FUNDING/COMPETING INTERESTS

K.T. is a practicing IVF gynaecologist and holds a minority stake in the publicly listed company Monash IVF. The other authors declare that they have no conflict of interest. This study was financially supported by Flinders University Medical School.

CYP3A4 Gene Is a Novel Biomarker for Predicting a Poor Prognosis in Hepatocellular Carcinoma

BACKGROUND/AIM

Project HOPE (High-tech Omics-based Patient Evaluation) began in 2014 using integrated gene expression profiling (GEP) of cancer tissues as well as diathesis of each patient who underwent operation at our Institution. The aim of this study was to identify novel genes displaying altered gene expression related to the survival and early recurrence after hepatectomy for hepatocellular carcinoma (HCC) using the results of integrated GEP analysis.

MATERIALS AND METHODS

The present study included 92 patients. Genes with aberrant expression were selected by the difference of expression levels with ≥10-fold change between tumor and non-tumor tissues.

RESULTS

GEP analysis showed that down-regulation was frequently observed in the PRSS8 (64%), CYP3A4 (61%) and EPCAM (57%) genes. Multivariate analysis revealed tumor stage ≥II (p=0.008) and down-regulation of the CYP3A4 gene (p=0.036) as independent predictor for overall survival. Furthermore, multivariate analysis identified maximum tumor diameter ≥74mm (p=0.008), presence of intrahepatic-metastasis (p=0.020), and down-regulation of CYP3A4 gene (p=0.019) as independent predictors for early recurrence.

CONCLUSION

CYP3A4 was identified as a novel tumor suppressor gene related to a poor prognosis in HCC.

The down-regulation of the CYP2C19 gene is associated with aggressive tumor potential and the poorer recurrence-free survival of hepatocellular carcinoma

Project HOPE (High-tech Omics-based Patient Evaluation) began in 2014 using integrated gene expression profiling (GEP) of cancer tissues as well as diathesis of each patient who underwent an operation at our institution. The aim of this study was to clarify the association between the expression of cytochrome P450s (CYP) genes and recurrence of hepatocellular carcinoma (HCC). The present study included 92 patients. Genes with aberrant expression were selected based on a ≥10-fold difference in the expression between tumor and non-tumor tissues. The GEP analysis showed that the down-regulated genes in tumor tissue were CYP3A4 in 56 patients (61%), CYP2C8 in 44 patients (48%), CYP2C19 in 30 patients (33%), CYP2D6 in 11 patients (12%), CYP3A5 in 7 patients (8%) and CYP1B1 in 2 patients (2%). There was no patients with down-regulation of the CYP17A1 gene. A multivariate analysis revealed that the presence of microscopic portal invasion (hazard ratio [HR] 2.57, 95% confidence interval [CI] 1.30–5.05 P = 0.006), the presence of intrahepatic-metastasis (HR 3.09 95% CI 1.52–6.29 P = 0.002) and down-regulation of the CYP2C19 gene (HR 3.69 95% CI 1.83–7.46 P < 0.001) were independent predictors for the recurrence-free survival (RFS). The down-regulation of the CYP2C19 gene were correlated with the RFS in HCC.

Down-regulation of B-Cell Translocation Gene 1 by Promoter Methylation in Colorectal Carcinoma

BACKGROUND

B-cell translocation gene 1 (BTG1) acts as a tumour suppressor in human malignancies. However, the precise mechanism of BTG1 down-regulation in colorectal carcinoma (CRC) remains unclear. We analyzed BTG1 expression in CRC cell lines and tissues and investigated the mechanism underlying the observed alterations.

MATERIALS AND METHODS

Real-time polymerase chain reaction (PCR) and western blot analyses were performed to analyze BTG1 expression in CRC cell lines. The methylation status of the BTG1 promoter region in cell lines was determined by methylation-specific PCR, and the effect of demethylation on BTG1 expression was explored with 5-aza-deoxycytidine treatment. BTG1 protein expression in CRC tissue samples was evaluated using immunostaining.

RESULTS

CRC cell lines and tissue samples expressed lower levels of BTG1 compared to controls, and BTG1 levels were significantly lower in metastatic than primary CRC. In BTG1-down-regulated CRC cell lines, the BTG1 promoter was highly methylated, and 5-aza-deoxycytidine significantly restored BTG1 expression.

CONCLUSION

BTG1 down-regulation in CRC occurs through epigenetic repression, which is involved in the development and progression of CRC.

Down-regulation of osteoprotegerin expression as a novel biomarker for colorectal carcinoma

A better understanding of tumor biology is important in the identification of molecules that are down-regulated in malignancy and in determining their role in tumor suppression. The aim of this study was to analyze osteoprotegerin (OPG) expression in colorectal carcinoma (CRC) and to investigate the underlying mechanism for changes in the expression of OPG. OPG expression was assessed in CRC tissue samples and cell lines. The methylation status of the OPG promoter region was determined, and the effects of demethylation on OPG expression were analyzed. The effects of recombinant OPG (rOPG) administration on cellular functions were also investigated. Clinical and prognostic implications of OPG protein expression in CRC patients were analyzed. The CRC tissues and cells showed significantly lower OPG expression. Pyrosequencing of OPG-silenced CRC cells revealed that the OPG gene promoter was highly methylated. Treatment with demethylating agent significantly elevated OPG mRNA and protein expression. rOPG significantly decreased cell viability and MMP-2 and VEGF-A production in CRC cells. Reduced OPG immunoreactivity was associated with aggressive oncogenic behavior in CRC. Also, OPG expression was found to be an independent predictor of recurrent hepatic metastasis and independent prognostic factor for worse survival rates. We demonstrated that OPG silencing in CRC occurs through epigenetic repression, and is involved in the development and progression of CRC. Our data suggest that OPG is a novel prognostic biomarker and a new therapeutic target for the treatment of patients with CRC.

Silicon reduces cadmium accumulation by suppressing expression of transporter genes involved in cadmium uptake and translocation in rice

Silicon (Si) alleviates cadmium (Cd) toxicity and accumulation in a number of plant species, but the exact molecular mechanisms responsible for this effect are still poorly understood. Here, we investigated the effect of Si on Cd toxicity and accumulation in rice (Oryza sativa) by using two mutants (lsi1 and lsi2) defective in Si uptake and their wild types (WTs). Root elongation was decreased with increasing external Cd concentrations in both WTs and mutants, but Si did not show an alleviative effect on Cd toxicity in all lines. By contrast, the Cd concentration in both the shoots and roots was decreased by Si in the WTs, but not in the mutants. Furthermore, Si supply resulted in a decreased Cd concentration in the root cell sap and xylem sap in the WTs, but not in the mutants. Pre-treatment with Si also decreased Cd accumulation in the WTs, but not in the mutants. Silicon slightly decreased Cd accumulation in the cell wall of the roots. The expression level of OsNramp5 and OsHMA2 was down-regulated by Si in the WTs, but not in the mutants. These results indicate that the Si-decreased Cd accumulation was caused by down-regulating transporter genes involved in Cd uptake and translocation in rice.

Ca2+ -dependent down-regulation of human histamine H1 receptors in Chinese hamster ovary cells

G_q/11 protein-coupled human histamine H₁ receptors in Chinese hamster ovary cells stimulated with histamine undergo clathrin-dependent endocytosis followed by proteasome/lysosome-mediated down-regulation. In this study, we evaluated the effects of a sustained increase in intracellular Ca²⁺ concentrations induced by a receptor-bypassed stimulation with ionomycin, a Ca²⁺ ionophore, on the endocytosis and down-regulation of H₁ receptors in Chinese hamster ovary cells. All cellular and cell-surface H₁ receptors were detected by the binding of [³ H]mepyramine to intact cells sensitive to the hydrophobic and hydrophilic H₁ receptor ligands, mepyramine and pirdonium, respectively. The pretreatment of cells with ionomycin markedly reduced the mepyramine- and pirdonium-sensitive binding sites of [³ H]mepyramine, which were completely abrogated by the deprivation of extracellular Ca²⁺ and partially by a ubiquitin-activating enzyme inhibitor (UBEI-41), but were not affected by inhibitors of calmodulin (W-7 or calmidazolium) and protein kinase C (chelerythrine or GF109203X). These ionomycin-induced changes were also not affected by inhibitors of receptor endocytosis via clathrin (hypertonic sucrose) and caveolae/lipid rafts (filipin or nystatin) or by inhibitors of lysosomes (E-64, leupeptin, chloroquine, or NH₄ Cl), proteasomes (lactacystin or MG-132), and a Ca²⁺ -dependent non-lysosomal cysteine protease (calpain) (MDL28170). Since H₁ receptors were normally detected by confocal immunofluorescence microscopy with an antibody against H₁ receptors, even after the ionomycin treatment, H₁ receptors appeared to exist in a form to which [³ H]mepyramine was unable to bind. These results suggest that H₁ receptors are apparently down-regulated by a sustained increase in intracellular Ca²⁺ concentrations with no process of endocytosis and lysosomal/proteasomal degradation of receptors.

Exonal switch down-regulates the expression of CD5 on blasts of acute T cell leukaemia

To date, CD5 expression and its role in acute T cell lymphoblastic leukaemia (T-ALL) have not been studied closely. We observed a significant reduction in surface expression of CD5 (sCD5) on leukaemic T cells compared to autologous non-leukaemic T cells. In this study, we have shown the molecular mechanism regulating the expression and function of CD5 on leukaemic T cells. A total of 250 patients suffering from leukaemia and lymphoma were immunophenotyped. Final diagnosis was based on their clinical presentation, morphological data and flow cytometry-based immunophenotyping. Thirty-nine patients were found to be of ALL-T origin. Amplification of early region of E1A and E1B transcripts of CD5 was correlated with the levels of surface and intracellular expression of CD5 protein. Functional studies were performed to show the effect of CD5 blocking on interleukin IL-2 production and survival of leukaemic and non-leukaemic cells. Lack of expression of sCD5 on T-ALL blasts was correlated closely with predominant transcription of exon E1B and significant loss of exon E1A of the CD5 gene, which is associated with surface expression of CD5 on lymphocytes. High expression of E1B also correlates with increased expression of cytoplasmic CD5 (cCD5) among leukaemic T cells. Interestingly, we observed a significant increase in the production of IL-2 by non-leukaemic T cells upon CD5 blocking, leading possibly to their increased survival at 48 h. Our study provides understanding of the regulation of CD5 expression on leukaemic T cells, and may help in understanding the molecular mechanism of CD5 down-regulation.

Role of the Development and/or Atopy?

Cough is typically associated with physical activity in children with asthma, but the characteristics of the relationship between cough and exercise has not been established under physiological conditions. The aim of the study was to describe the effect of exercise on the reflex cough response elicited by a single breath of capsaicin in non-asthmatic children. A group of non-asthmatic adults was studied as reference. Thirty children and 29 adults were recruited. The cough reflex sensitivity to capsaicin was first determined to establish the dose that provokes 5 cough efforts (C5). The number of coughs elicited by C5 (NC5) was then compared at baseline and during a standardized submaximal treadmill exercise. Data are expressed as median (interquartile range). Children and adults showed a significant decrease in NC5 (respectively from 5.0 (4.0–6.0) to 2.5 (2.0–4.0), p < 0.0005 and from 6.0 (5.0–7.0) to 2.0 (0.0–3.0, p < 0.0005). During exercise, NC5 was observed to decrease in all adult subjects, but in only 24/30 children (80%, p = 0.02). A trend for a higher incidence of personal and familial atopy was observed in children that lacked cough down-regulation during exercise compared with other children. It is concluded that the cough reflex response to capsaicin is down regulated by exercise in both children and adults. The effect however is less consistently observed in the former. The difference may reflect maturation of descending inhibitory pathways of the cough reflex, but may also be associated to atopy. The data stress the importance of assessing the time relationship of cough and exercise in questionnaire studies of asthma.

Predictive significance of HMGCS2 for prognosis in resected Chinese esophageal squamous cell carcinoma patients

Despite a series of attempts during the last decades, the prognosis of esophageal squamous cell carcinoma (ESCC) remains poor. Different responses of individual tumors encouraged us to look for valuable prognostic markers. As a key regulator controlling the anabolic ketogenic pathway, 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) has been reported to play a crucial role in colorectal cancer and prostate cancer. However, its importance to ESCC has not been verified. Therefore, a large cohort retrospective study was planned, to investigate the relationship between HMGCS2 expression and ESCC prognosis. By adopting real-time polymerase chain reaction (PCR) and immunohistochemical (IHC) staining, HMGCS2 expression was examined in tissues of 300 ESCC patients with complete resection. Besides, the association between HMGCS2 protein expression and survival time was evaluated through chi-square test and Kaplan–Meier analysis. With the use of Cox-proportional hazards model, the prognostic impact of clinicopathologic variables and biomarker expression was evaluated. Compared with their non-tumor counterparts, HMGCS2 downregulation occurred in 65.5% and 37.6% of primary ESCCs on the mRNA and protein levels (P<0.001), respectively. On the protein level, HMGCS2 expression was associated with tumor cell differentiation (P=0.003), pT status (P=0.006), and TNM stage (P=0.010). In the down-HMGCS2 expression group, the 5-year overall survival (OS) and relapse-free survival (RFS) are poorer than those in the normal expression group (19 months vs 24 months, P=0.002; 13 months vs 17 months, P=0.007, respectively). According to the TNM stage, stratified analysis revealed that its discernibility on RFS was only pronounced in patients with advanced clinical stage (P=0.001). In addition, multivariate Cox regression analysis showed that HMGCS2 expression was an independent risk factor for RFS (P=0.032) instead of OS (P=0.099). The findings of this study provided the evidence that HMGSC2 represented a potential novel prognostic biomarker for ESCC patients.

The role of long non-coding RNA HOTAIR in the progression and development of laryngeal squamous cell carcinoma interacting with EZH2

CONCLUSIONS

The aberrant expression of long non-coding RNA HOTAIR and transmethylase EZH2 played important roles in the progression and development of laryngeal squamous cell carcinoma (LSCC).

OBJECTIVES

This research was aimed to explore the expression and correlation with clinicopathological characteristics of HOTAIR and EZH2 in LSCC, and to evaluate the function of the two in regulating the proliferation and cis-platinum resistance processes of LSCC.

METHODS

Quantitative real time-PCR (qPCR) was conducted to measure the expression of HOTAIR and EZH2 in tissue samples. Clinicopathological features were collected and statistically analyzed combining with the expression of HOTAIR and EZH2. The variance of EZH2 with down-regulating HOTAIR was measured by qPCR. CCK-8 proliferation test was conducted to detect the proliferation feature in LSCC cells. After cultured with a series of cis-platinum concentrations for 24 h, cell viability was detected using CCK-8 assay, and the inhibition rates were calculated.

RESULTS

HOTAIR and EZH2 were over-expressed in LSCC tissue. The higher expression was significantly related to T phase, pathological grades, and risk of lymphatic metastasis of LSCC. Suppressing HOTAIR expression stimulated EZH2 expressing, promoted the proliferation of AMC-HN8 cells, and increased the sensitivity to cis-platinum of the LSCC cells.

Differential Phosphorylation Provides a Switch to Control How α-Arrestin Rod1 Down-regulates Mating Pheromone Response in Saccharomyces cerevisiae

G-protein-coupled receptors (GPCRs) are integral membrane proteins that initiate stimulus-dependent activation of cognate heterotrimeric G-proteins, triggering ensuing downstream cellular responses. Tight regulation of GPCR-evoked pathways is required because prolonged stimulation can be detrimental to an organism. Ste2, a GPCR in Saccharomyces cerevisiae that mediates response of MATa haploids to the peptide mating pheromone α-factor, is down-regulated by both constitutive and agonist-induced endocytosis. Efficient agonist-stimulated internalization of Ste2 requires its association with an adaptor protein, the α-arrestin Rod1/Art4, which recruits the HECT-domain ubiquitin ligase Rsp5, allowing for ubiquitinylation of the C-terminal tail of the receptor and its engagement by the clathrin-dependent endocytic machinery. We previously showed that dephosphorylation of Rod1 by calcineurin (phosphoprotein phosphatase 2B) is required for optimal Rod1 function in Ste2 down-regulation. We show here that negative regulation of Rod1 by phosphorylation is mediated by two distinct stress-activated protein kinases, Snf1/AMPK and Ypk1/SGK1, and demonstrate both in vitro and in vivo that this phospho-regulation impedes the ability of Rod1 to promote mating pathway desensitization. These studies also revealed that, in the absence of its phosphorylation, Rod1 can promote adaptation independently of Rsp5-mediated receptor ubiquitinylation, consistent with recent evidence that α-arrestins can contribute to cargo recognition by both clathrin-dependent and clathrin-independent mechanisms. However, in cells lacking a component (formin Bni1) required for clathrin-independent entry, Rod1 derivatives that are largely unphosphorylated and unable to associate with Rsp5 still promote efficient adaptation, indicating a third mechanism by which this α-arrestin promotes desensitization of the pheromone-response pathway.

Down-regulation of CEACAM1 in breast cancer

Carcinoembryonic antigen-related adhesion molecule 1 (CEACAM1) is a type 1 transmembrane glycoprotein belonging to the CEA family, which has been found to exist as either soluble forms in body fluids or membrane-bound forms on the cell surface. Aberrant CEACAM1 expression is associated with tumor progression and has been found in a variety of human malignancies. Increasing interest has been devoted to the expression of CEACAM1 in breast cancer, but most of these findings are contradictory. The aim of this study was to investigate CEACAM1 expression in breast cancer in greater detail. Using immunohistochemical staining, we found that CEACAM1 expression was reduced or lost in breast cancer tissues compared with noncancerous breast tissues. In addition, soluble CEACAM1 levels in the culture medium of breast cancer cell lines were significantly lower than those in a nontumorigenic breast epithelial cell line. Immunofluorescence analysis consistently showed that breast cancer cell lines have relatively low expression of membrane-bound CEACAM1. Furthermore, CEACAM1 mRNA and protein expression levels were down-regulated in breast cancer cell lines as measured using real-time reverse transcriptase-polymerase chain reaction and western blot analysis, respectively. Taken together, our results demonstrate a systematic down-regulation of CEACAM1 in breast cancer and suggest that a strategy to restore CEACAM1 expression may be helpful for the treatment of breast cancer.

MiR-302c-3p suppresses invasion and proliferation of glioma cells via down-regulating metadherin (MTDH) expression

Glioma is the most common malignant brain tumors with poor prognosis. The molecular events involved in the development and progression of glioma remain unclear. In this study, the expression levels of miR-302c-3p were examined in glioma tissues by qRT-PCR. The in vitro and in vivo functional effects of miR-302c-3p were examined further. Luciferase reporter assays were conducted to confirm the targeting associations. Results showed that the expression level of miR-302c-3p in glioma tissues was significantly lower than those in normal brain tissues (P < 0.001). The decreased expression of mi-302c-3p in glioma was positively associated with WHO grade (P < 0.001). Up-regulation of MTDH was also detected in glioma tumors compared with normal brain tissues (P = 0.0027) and is inversely correlated with miR-302c-3p expression (P = 0.003, R(2) = 0.4065). MTDH mRNA is a direct target of miR-302c-3p, whose ectopic expression decreases MTDH expression through binding to its 3'-untranslated region. Overexpression of miR-302c-3p results in a dramatic inhibition of glioma cells proliferation and invasion in vitro and in vivo. These data suggest that miR-302c-3p play a pivotal role in the progression of glioma by targeting MTDH and is a potential inhibitor in glioma treatment.

Identification of low miR-105 expression as a novel poor prognostic predictor for human glioma

Glioma is the most common and aggressive brain tumor with poor clinical outcome. Identification and development of new biomarkers could be beneficial for diagnosis and prognosis of glioma patients. Recent studies have showed evidences that dysregulation of microRNAs (miRNAs) is involved in glioma tumorigenesis. Therefore, we attempted to identify specific miRNAs as prognostic and predictive markers for glioma. We statistically compared expression profile of 365 miRNAs between WHO grade IV and grade III gliomas, by qRT-PCR. MiR-105 was identified as a remarkably decreased miRNA in grade IV gliomas compared with grade III gliomas (P=0.012, fold change =0.04). We subsequently examined its expression levels in an independent series of gliomas, and statistically analyzed the associations between miR-105 expression and clinicopathological characteristics and survivals of these glioma patients. MiR-105 showed remarkably decreased expression in gliomas as compared to non-neoplastic brains. And grade IV gliomas had significantly lower miR-105 expression compared with grade III and II gliomas (both P<0.001). Additionally, low miR-105 expression was statistically associated with advanced tumor grade, advanced patient's age and low pre-operative Karnofsky performance score (all P<0.001). Furthermore, patients with low miR-105 expression had significantly poorer survival by Kaplan-Meier method (P<0.001). Multivariate analysis indicated miR-105 as an independent prognostic indicator for glioma patients (P=0.018, risk ratio =4.2). Our results suggested that low expression of miR-105 may correlate with unfavorable clinical outcome and be involved in tumorigenesis and aggressive progression of glioma. And miR-105 may be a novel biomarker in prognostic prediction for glioma.

Effect of Antimuscarinic Autoantibodies in Primary Sjögren's Syndrome

The presence of functional autoantibodies against the muscarinic type 3 receptor (M3R) has been reported in primary Sjögren's syndrome (pSS). However, the pathogenic role of these autoantibodies in pSS development remains to be elucidated. In this experiment, we investigated a pathologic role of pSS autoantibodies (pSS IgG) associated with downregulation of the major histocompatibility complex I (MHC I) molecule with M3R through internalization. Anti-M3R autoantibodies in purified control and pSS IgG were detected using 4 synthesized cyclic M3R peptides by enzyme-linked immunosorbent assay. The binding reactivity of pSS IgG to M3R in situ was analyzed by a dual immunostaining method. Surface expression, interaction, and internalization of M3R with MHC I were analyzed by immunofluorescence confocal microscopy and biochemical assays. Synthetic cyclic peptides M3RP(205-221) and M3RP(520-527) showed significantly high reactivity with pSS IgG compared to the control IgG or the other 3 peptides (P < 0.05). Significantly high reactivity of pSS IgG to M3R in situ was observed. PSS IgG increased the interaction of membrane M3R with MHC I and induced their internalization in primary human submandibular gland cells. The pSS IgG-induced internalization of M3R with MHC I was significantly inhibited by the cholesterol-sequestering drug filipin. Our novel finding-namely, strong downregulation of the membrane MHC I with M3R through internalization of the cholesterol-rich microdomain associating with anti-M3R autoantibodies-could be an important mechanism contributing to the impaired salivation seen in pSS and linking secretory hypofunction to autoimmune pathogenesis.

The criteria for optimal down-regulation with gonadotropin-releasing hormone-agonist: a retrospective cohort study

OBJECTIVE

The objective of this study is to investigate whether the degree of down-regulation using GnRH-agonists is associated with pregnancy outcomes.

STUDY DESIGN

This retrospective analysis was performed on 2708 cycles from 2514 patients undergoing down-regulation with the luteal phase long protocol. The serum oestradiol (E2D) and luteinising hormone (LHD) levels, the diameter of the largest follicle (DLFD) and the endometrial-thickness (ENTD) after down-regulation were used to evaluate the degree of down-regulation. One-way analysis of variance with the Bonferroni adjustment, the chi-square test and multivariate logistic regression analyses were used for the statistical analysis.

RESULTS

The cumulative clinical pregnancy rates (CCPR) and the cumulative live birth rates (CLBR) were higher in the cycles with E2D < 30 pg/ml (63.7%, OR = 1.405 (1.055-1.870) and 56.8%, OR = 1.372 (1.039-1.813)) and 30-55pg/ml (66.8%, OR = 1.439 (1.104-1.874) and 59.8%, OR = 1.397 (1.080-1.806)) than in those with E2D > 55 pg/ml (62.8% and 54.7%). There was a trend towards lower CCPRs and CLBRs in the cycles with DLFD > 10 mm or ENTD ≥ 6 mm; however, this difference was not significant.

CONCLUSION

The degree of down-regulation is associated with ovarian response, pregnancy, and live birth. We propose the following criteria for optimal down-regulation: E2D 30-55 pg/ml, ENTD < 6 mm, and no apparent ovarian activity.

Down-regulated expression of monocyte/macrophage major histocompatibility complex receptors in human and mouse monocytes by expression of their ligands

Mouse monocyte/macrophage major histocompatibility complex (MHC) receptor 1 (MMR1; or MMR2) specific for H-2D(d) (or H-2K(d) ) molecules is expressed on monocytes from non-H-2D(d) (or non-H-2K(d) ), but not those from H-2D(d) (or H-2K(d) ), inbred mice. The MMR1 and/or MMR2 is essential for the rejection of H-2D(d) - and/or H-2K(d) -transgenic mouse skin onto C57BL/6 (H-2D(b) K(b) ) mice. Recently, we found that human leucocyte antigen (HLA)-B44 was the sole ligand of human MMR1 using microbeads that had been conjugated with 80 types of HLA class I molecules covering 94·2% (or 99·4%) and 92·4% (or 96·2%) of HLA-A and B molecules of Native Americans (or Japanese), respectively. In the present study, we also explored the ligand specificity of human MMR2 using microbeads. Microbeads coated with HLA-A32, HLA-B13 or HLA-B62 antigens bound specifically to human embryonic kidney (HEK)293T or EL-4 cells expressing human MMR2 and to the solubilized MMR2-green fluorescent protein (GFP) fusion protein; and MMR2(+) monocytes from a volunteer bound HLA-B62 molecules with a Kd of 8·7 × 10(-9)  M, implying a three times down-regulation of MMR2 expression by the ligand expression. H-2K(d) (or H-2D(d) ) transgene into C57BL/6 mice down-regulated not only MMR2 (or MMR1) but also MMR1 (or MMR2) expression, leading to further down-regulation of MMR expression. In fact, monocytes from two (i.e. MMR1(+) /MMR2(+) and MMR1(-) /MMR2(-) ) volunteers bound seven to nine types of microbeads among 80, indicating ≤ 10 types of MMR expression on monocytes. The physiological role of constitutive MMRs on monocytes possibly towards allogeneic (e.g. fetal) cells in the blood appears to be distinct from that of inducible MMRs on macrophages toward allografts in tissue.

Carbon dioxide stimulation of photosynthesis in Liquidambar styraciflua is not sustained during a 12-year field experiment

Elevated atmospheric CO2 (eCO2) often increases photosynthetic CO2 assimilation (A) in field studies of temperate tree species. However, there is evidence that A may decline through time due to biochemical and morphological acclimation, and environmental constraints. Indeed, at the free-air CO2 enrichment (FACE) study in Oak Ridge, Tennessee, A was increased in 12-year-old sweetgum trees following 2 years of ∼40 % enhancement of CO2. A was re-assessed a decade later to determine if the initial enhancement of photosynthesis by eCO2 was sustained through time. Measurements were conducted at prevailing CO2 and temperature on detached, re-hydrated branches using a portable gas exchange system. Photosynthetic CO2 response curves (A versus the CO2 concentration in the intercellular air space (Ci); or A-Ci curves) were contrasted with earlier measurements using leaf photosynthesis model equations. Relationships between light-saturated photosynthesis (Asat), maximum electron transport rate (Jmax), maximum Rubisco activity (Vcmax), chlorophyll content and foliar nitrogen (N) were assessed. In 1999, Asat for eCO2 treatments was 15.4 ± 0.8 μmol m(-2) s(-1), 22 % higher than aCO2 treatments (P < 0.01). By 2009, Asat declined to <50 % of 1999 values, and there was no longer a significant effect of eCO2 (Asat = 6.9 or 5.7 ± 0.7 μmol m(-2) s(-1) for eCO2 or aCO2, respectively). In 1999, there was no treatment effect on area-based foliar N; however, by 2008, N content in eCO2 foliage was 17 % less than that in aCO2 foliage. Photosynthetic N-use efficiency (Asat : N) was greater in eCO2 in 1999 resulting in greater Asat despite similar N content, but the enhanced efficiency in eCO2 trees was lost as foliar N declined to sub-optimal levels. There was no treatment difference in the declining linear relationships between Jmax or Vcmax with declining N, or in the ratio of Jmax : Vcmax through time. Results suggest that the initial enhancement of photosynthesis to elevated CO2 will not be sustained through time if N becomes limited.

Decreased expression of receptor tyrosine kinase of EphB1 protein in renal cell carcinomas

Receptors tyrosine kinase of Eph superfamily plays an important role in human cancers. We previously found that EphB1 subtype is down-regulated in gastric cancer, colorectal cancer and ovary serous carcinoma. Fore the more, the decreased expression of EphB1 is related to invasion and metastasis in cancers. Although EphB1 has been revealed as an important receptor in cancers, our understanding of its roles in renal cell carcinoma (RCC) is limited. In the present study, using specific anit-EphB1 polyclonal antibody and immunohistochemistry, we evaluated EphB1 protein expression levels in RCC specimens surgically resected from 82 patients (including 62 conventional clear-cell RCC, 10 papillary, and 10 chromophobic RCC cases). We found EphB1 protein is positively expressed in the epithelium of renal tubules. Decreased expression of EphB1 was found in all RCC carcinomas compared with expression in the normal epithelium of renal tubules. EphB1 protein moderately expressed in chromophobic RCC, weakly expressed in clear-cell RCC and negatively expressed in papillary RCC. Our results indicate that EphB1 may be involved in carcinogenesis of RCC, the molecular mechanisms of down-regulation of EphB1 including genetic and epigenetic alterations and the dedicated roles of EphB1 in occurrence and progress of RCC need to be explicated in next step.

Meiotic sex chromosome inactivation in Drosophila

In several different taxa, there is indubitable evidence of transcriptional silencing of the X and Y chromosomes in male meiotic cells of spermatogenesis. However, the so called meiotic sex chromosome inactivation (MSCI) has been recently a hot bed for debate in Drosophila melanogaster. This review covers cytological and genetic observations, data from transgenic constructs with testis-specific promoters, global expression profiles obtained from mutant, wild-type, larvae and adult testes as well as from cells of different stages of spermatogenesis. There is no dispute on that D. melanogaster spermatogenesis presents a down-regulation of X chromosome that does not result from the lack of dosage compensation. However, the issue is currently focused on the level of reduction of X-linked expression, the precise time it occurs and how many genes are affected. The deep examination of data and experiments in this review exposes the limitations intrinsic to the methods of studying MSCI in D. melanogaster. The current methods do not allow us to affirm anything else than the X chromosome down-regulation in meiosis (MSCI). Therefore, conclusion about level, degree or precise timing is inadequate until new approaches are implemented to know the details of MSCI or other processes involved for D. melanogaster model.

Lack of photosynthetic or stomatal regulation after 9 years of elevated [CO2] and 4 years of soil warming in two conifer species at the alpine treeline

Alpine treelines are temperature-limited vegetation boundaries. Understanding the effects of elevated [CO2 ] and warming on CO2 and H2 O gas exchange may help predict responses of treelines to global change. We measured needle gas exchange of Larix decidua Mill. and Pinus mugo ssp. uncinata DC trees after 9 years of free air CO2 enrichment (575 µmol mol(-1) ) and 4 years of soil warming (+4 °C) and analysed δ(13) C and δ(18) O values of needles and tree rings. Tree needles under elevated [CO2 ] showed neither nitrogen limitation nor end-product inhibition, and no down-regulation of maximal photosynthetic rate (Amax ) was found. Both tree species showed increased net photosynthetic rates (An ) under elevated [CO2 ] (L. decidua: +39%; P. mugo: +35%). Stomatal conductance (gH2O ) was insensitive to changes in [CO2 ], thus transpiration rates remained unchanged and intrinsic water-use efficiency (iWUE) increased due to higher An . Soil warming affected neither An nor gH2O . Unresponsiveness of gH2O to [CO2 ] and warming was confirmed by δ(18) O needle and tree ring values. Consequently, under sufficient water supply, elevated [CO2 ] induced sustained enhancement in An and lead to increased C inputs into this ecosystem, while soil warming hardly affected gas exchange of L. decidua and P. mugo at the alpine treeline.

NAC1, A POZ/BTB protein interacts with Parkin and may contribute to Parkinson's disease

Loss-of-function in the Parkin protein is thought to play a part in causing neuronal cell death in patients with Parkinson's disease. This study explores the effect of Parkin degradation, via the overexpression of nucleus accumbens 1 (NAC1), on cell viability. It was found that NAC1 and Parkin are co-localized within the cell and interact with one another, leading to a decrease in Parkin levels. Moreover, NAC1 down-regulates Parkin by presenting it for ubiquitin-dependent proteasome degradation, which causes a decrease in proteasomal activity in neuronal cells. Consequently, this decrease in proteasomal activity leads to an increase in the cells' susceptibility to proteasome inhibition-induced toxicity. It was also found that Parkin and NAC1 are key proteins found to be present mainly in the cytoplasm and are co-localized in neurons of Parkinson's disease patients. Interestingly, mutation in the POZ/BTB domain (Q23L) of NAC1 disrupts the co-localization and interaction of NAC1 with Parkin and it further abrogates the proteasome inhibition-induced toxicity. We further observed that co-transfection of the mutant form of NAC1 with Parkin reversed the proteasome activity and 20S proteasome protein levels. These results indicate a novel interaction between NAC1 and Parkin that leads to neuronal cell death, a main characteristic in Parkinson's disease.

MicroRNAs in Liver Disease: Bench to Bedside

MicroRNAs (miRs) are small non-coding RNAs that negatively regulate gene expression by pairing with partially complementary target sequences in the 3'UTRs of mRNAs to promote degradation and/or block translation. Aberrant miR expression is associated with development of multiple diseases including hepatic diseases. The role of miRs in the regulation of gene expression and rapid progress in the field of microRNA research are resulting in momentum toward development of diagnostic markers and novel therapeutic strategies for human liver diseases. Recent studies provide clear evidence that miRs are abundant in the liver and modulate a diverse spectrum of biological functions, thereby supporting an association between alterations of miR homeostasis and pathological liver diseases. Here we review the role of miRs in liver as their physiological and pathological importance has been demonstrated in metabolism, immunity, viral hepatitis, oncogenesis, fatty liver diseases (alcoholic and non-alcoholic), drug-induced liver injury, fibrosis as well as acute liver failure.

Bisoprolol reverses down-regulation of potassium channel proteins in ventricular tissues of rabbits with heart failure

Remodeling of ion channels is an important mechanism of arrhythmia induced by heart failure (HF). We investigated the expression of potassium channel encoding genes in the ventricles of rabbit established by volume-overload operation followed with pressure-overload. The reversible effect of these changes with bisoprolol was also evaluated. The HF group exhibited left ventricular enlargement, systolic dysfunction, prolongation of corrected QT interval (QTc), and increased plasma brain natriuretic peptide levels in the HF rabbits. Several potassium channel subunit encoding genes were consistently down-regulated in the HF rabbits. After bisoprolol treatment, heart function was improved significantly and QTc was shortened. Additionally, the mRNA expression of potassium channel subunit genes could be partially reversed. The down-regulated expression of potassium channel subunits Kv4.3, Kv1.4, KvLQT1, minK and Kir 2.1 may contribute to the prolongation of action potential duration in the heart of rabbits induced by volume combined with pressure overload HF. Bisoprolol could partially reverse these down-regulations and improve heart function.

SymRK and the nodule vascular system: an underground connection

Symbiotic legume-rhizobia relationship leads to the formation of nitrogen-fixing nodules. Successful nodulation depends on the expression and cross-talk of a batttery of genes, among them SymRK (symbiosis receptor-like kinase), a leucine-rich repeat receptor-like kinase. SymRK is required for the rhizobia invasion of root hairs, as well as for the infection thread and symbiosome formation. Using immunolocalization and downregulation strategies we have recently provided evidence of a new function of PvSymRK in nodulation. We have found that a tight regulation of PvSymRK expression is required for the accurate development of the vascular bundle system in Phaseolus vulgaris nodules.

Downregulation of the tumour suppressor p16INK4A contributes to the polarisation of human macrophages toward an adipose tissue macrophage (ATM)-like phenotype

AIMS/HYPOTHESIS

Human adipose tissue macrophages (ATMs) display an alternatively activated (M2) phenotype, but are still able to produce excessive inflammatory mediators. However, the processes driving this particular ATM phenotype are not understood. Genome-wide association studies associated the CDKN2A locus, encoding the tumour suppressor p16(INK4A), with the development of type 2 diabetes. In the present study, p16(INK4A) levels in human ATMs and the role of p16(INK4A) in acquiring the ATM phenotype were assessed.

METHODS

Gene expression of p16 ( INK4A ) in ATMs was analysed and compared with that in monocyte-derived macrophages (MDMs) from obese patients or with macrophages from human atherosclerotic plaques (AMs). Additionally, p16(INK4A) levels were studied during macrophage differentiation and polarisation of monocytes isolated from healthy donors. The role of p16(INK4A) in MDMs from healthy donors was investigated by small interfering (si)RNA-mediated silencing or adenovirus-mediated overproduction of p16(INK4A).

RESULTS

Compared with MDMs and AMs, ATMs from obese patients expressed lower levels of p16 ( INK4A ). In vitro, IL-4-induced M2 polarisation resulted in lower p16(INK4A) protein levels after differentiation of monocytes from healthy donors in macrophages. Silencing of p16(INK4A) in MDMs mediated by siRNA increased the expression of M2 marker genes and enhanced the response to lipopolysaccharide (LPS), to give a phenotype resembling that of ATM. By contrast, adenovirus-mediated overproduction of p16(INK4A) in MDMs diminished M2 marker gene expression and the response to LPS. Western blot analysis revealed that p16(INK4A) overproduction inhibits LPS- and palmitate-induced Toll-like receptor 4 (TLR4)-nuclear factor of κ light polypeptide gene enhancer in B cells (NF-κB) signalling.

CONCLUSIONS/INTERPRETATION

These results show that p16(INK4A) inhibits the acquisition of the ATM phenotype. The age-related increase in p16(INK4A) level may thus influence normal ATM function and contribute to type 2 diabetes risk.

Regulatory mechanisms of tumor suppressor P16(INK4A) and their relevance to cancer

P16(INK4A) (also known as P16 and MTS1), a protein consisting exclusively of four ankyrin repeats, is recognized as a tumor suppressor mainly because of the prevalence of genetic inactivation of the p16(INK4A) (or CDKN2A) gene in virtually all types of human cancers. However, it has also been shown that an elevated level of expression (upregulation) of P16 is involved in cellular senescence, aging, and cancer progression, indicating that the regulation of P16 is critical for its function. Here, we discuss the regulatory mechanisms of P16 function at the DNA level, the transcription level, and the posttranscriptional level, as well as their implications for the structure-function relationship of P16 and for human cancers.

Adaptive effects of the beta2-agonist clenbuterol on expression of beta2-adrenoceptor mRNA in rat fast-twitch fiber-rich muscles

Administration of the beta(2)-agonist clenbuterol has been shown to reduce the expression of beta(2)-adrenoceptor (AR) mRNA in fast-twitch fiber-rich (extensor digitorum longus, EDL) muscle without changing that in slow-twitch fiber-rich (soleus, SOL) muscle in rats. However, the regulatory mechanism for muscle fiber type-dependent down-regulation of the expression of beta(2)-AR mRNA induced by clenbuterol is still unclear. Therefore, mRNA expression of transcriptional and post-transcriptional regulatory factors for beta(2)-AR mRNA levels in fast-twitch fiber-rich (EDL and plantaris, PLA) and slow-twitch fiber-rich (SOL) muscles in clenbuterol-administered (1.0 mg/kg body weight/day for 10 days, subcutaneous) rats was studied by real-time reverse transcription-polymerase chain reaction. Administration of clenbuterol significantly reduced expression of beta(2)-AR mRNA in EDL and PLA muscles without changing that in SOL muscle. Administration of clenbuterol also significantly reduced the mRNA expression of transcriptional regulatory factor (glucocorticoid receptor) and mRNA stabilizing factor (Hu antigen R) in EDL and PLA muscles without changing those in SOL muscle. These results suggest that muscle fiber type-dependent effects of clenbuterol on expression of beta(2)-AR mRNA are closely related to the down-regulation of mRNA expression of transcriptional and post-transcriptional regulatory factors for beta(2)-AR mRNA levels.

Phorbol ester induced trafficking-independent regulation and enhanced phosphorylation of the dopamine transporter associated with membrane rafts and cholesterol

We examined the mechanisms involved in protein kinase C (PKC)-dependent down-regulation of dopamine transporter (DAT) activity and cell surface expression by treating heterologously expressing cells with the clathrin-mediated endocytosis inhibitor concanavalin A (Con A) or the cholesterol depleter/membrane raft disrupter methyl-beta-cyclodextrin (MbetaC) prior to treatment with the PKC activator phorbol 12-myristate, 13-acetate (PMA). Con A blocked PMA-induced surface reductions of DAT but only partially inhibited down-regulation, while MbetaC partially blocked down-regulation but did not inhibit loss of cell surface DAT, demonstrating that PKC-induced DAT down-regulation occurs by a combination of trafficking and non-trafficking processes. Using density-gradient centrifugation, we found that DATs are distributed approximately equally between Triton-insoluble, cholesterol-rich membrane rafts and Triton-soluble non-raft membranes. DATs in both populations are present at the cell surface and are active for dopamine and cocaine binding. PMA-induced loss of cell surface DAT occurred only from non-raft populations, demonstrating that non-raft DATs are regulated by trafficking events and indicating the likelihood that the cholesterol-dependent non-trafficking regulatory mechanism occurs in rafts. PMA did not affect the DAT raft-non-raft distribution but stimulated the phosphorylation of DAT to a substantially greater level in rafts than non-rafts. These findings reveal a previously unknown role for cholesterol in DAT function and demonstrate the presence of distinct subcellular DAT populations that possess multiple regulatory differences that may impact dopaminergic neurotransmission.

Interleukin-1beta-induced insulin resistance in adipocytes through down-regulation of insulin receptor substrate-1 expression

Inflammation is associated with obesity and insulin resistance. Proinflammatory cytokines produced by adipose tissue in obesity could alter insulin signaling and action. Recent studies have shown a relationship between IL-1beta level and metabolic syndrome or type 2 diabetes. However, the ability of IL-1beta to alter insulin signaling and action remains to be explored. We demonstrated that IL-1beta slightly increased Glut 1 translocation and basal glucose uptake in 3T3-L1 adipocytes. Importantly, we found that prolonged IL-1beta treatment reduced the insulin-induced glucose uptake, whereas an acute treatment had no effect. Chronic treatment with IL-1beta slightly decreased the expression of Glut 4 and markedly inhibited its translocation to the plasma membrane in response to insulin. This inhibitory effect was due to a decrease in the amount of insulin receptor substrate (IRS)-1 but not IRS-2 expression in both 3T3-L1 and human adipocytes. The decrease in IRS-1 amount resulted in a reduction in its tyrosine phosphorylation and the alteration of insulin-induced protein kinase B activation and AS160 phosphorylation. Pharmacological inhibition of ERK totally inhibited IL-1beta-induced down-regulation of IRS-1 mRNA. Moreover, IRS-1 protein expression and insulin-induced protein kinase B activation, AS160 phosphorylation, and Glut 4 translocation were partially recovered after treatment with the ERK inhibitor. These results demonstrate that IL-1beta reduces IRS-1 expression at a transcriptional level through a mechanism that is ERK dependent and at a posttranscriptional level independently of ERK activation. By targeting IRS-1, IL-1beta is capable of impairing insulin signaling and action, and could thus participate in concert with other cytokines, in the development of insulin resistance in adipocytes.

Constitutional downregulation of SEMA5A expression in autism

There is strong evidence for the importance of genetic factors in idiopathic autism. The results from independent twin and family studies suggest that the disorder is caused by the action of several genes, possibly acting epistatically. We have used cDNA microarray technology for the identification of constitutional changes in the gene expression profile associated with idiopathic autism. Samples were obtained and analyzed from 6 affected subjects belonging to multiplex autism families and from 6 healthy controls. We assessed the expression levels for approximately 7,700 genes by cDNA microarrays using mRNA derived from Epstein-Barr virus-transformed B lymphocytes. The microarray data were analyzed in order to identify up- or downregulation of specific genes. A common pattern with nine downregulated genes was identified among samples derived from individuals with autism when compared to controls. Four of these nine genes encode proteins involved in biological processes associated with brain function or the immune system, and are consequently considered as candidates for genes associated with autism. Quantitative real-time PCR confirms the downregulation of the gene encoding SEMA5A, a protein involved in axonal guidance. Epstein-Barr virus should be considered as a possible source for altered expression, but our consistent results make us suggest SEMA5A as a candidate gene in the etiology of idiopathic autism.

Photosynthetic down-regulation over long-term CO2 enrichment in leaves of sour orange (Citrus aurantium) trees

•  Understanding how trees are affected by a long-term increase in atmospheric CO₂ is crucial to understanding the future impact of global climate change. Measurements of photosynthetic characteristics were made in sour orange trees (Citrus aurantium) growing under an enhanced CO₂ atmosphere and N-replete soil for 14 yr to determine whether photosynthetic down-regulation had occurred. •  Photosynthesis, A : C_i gas exchange relationships and Rubisco activity and content were measured throughout the 14th year of the experiment. The CO₂ -induced enhancement ratio of photosynthesis was calculated and compared with estimates of the enhancement of cumulative wood biomass production. •  Content of the large subunit of Rubisco was significantly reduced by CO₂ enrichment indicating that down-regulation had occurred. A high correlation between the CO₂ -induced enhancement of photosynthesis and the enhancement of cumulative wood biomass production suggested that the decline in wood biomass production was closely related to the decline in photosynthesis. •  These results indicate that long-term CO₂ enrichment can result in photosynthetic down-regulation in leaves of trees, even under nonlimiting N conditions.

Desensitization of alpha 2A-adrenoceptor signalling by modest levels of adrenaline is facilitated by beta 2-adrenoceptor-dependent GRK3 up-regulation

(1) Adrenaline (ADR) and noradrenaline (NA) can simultaneously activate inhibitory alpha(2)- and stimulatory beta-adrenoceptors (AR). However, ADR and NA differ significantly in that ADR is a potent beta(2)-AR agonist while NA is not. Only recently has the interaction resulting from the simultaneous activation of alpha(2)- and beta(2)-AR been examined at the cellular level to determine the mechanisms of alpha(2)-AR regulation following concomitant activation of both alpha(2)- and beta(2)-ARs by chronic ADR. (2) This study evaluates beta(2)-AR regulation of alpha(2A)-AR signalling following chronic ADR (300 nM) and NA (1 and 30 micro M) treatments of BE(2)-C human neuroblastoma cells that natively express both beta(2)- and alpha(2A)-ARs. (3) Chronic (24 h) treatment with ADR (300 nM) desensitized the response to the alpha(2A)-AR agonist, brimonidine, in BE(2)-C cells. Addition of the beta-AR antagonist, propranolol, blocked the ADR-induced alpha(2A)-AR desensitization. Unlike ADR, chronic NA (1 micro M) treatment had no effect on the alpha(2A)-AR response. However if NA was increased to 30 micro M for 24 h, alpha(2A)-AR desensitization was observed; this desensitization was partially reversed by propranolol. (4) Chronic ADR (300 nM) treatment reduced alpha(2A)-AR binding levels, contributing to the alpha(2A)-AR desensitization. This decrease was prevented by addition of propranolol during ADR treatment. Chronic NA (30 micro M), like ADR, treatment lowered specific binding, whereas 1 micro M NA treatment was without effect. (5) Chronic ADR treatment produced a significant increase in GRK3 levels and this was blocked by propranolol or GRK2/3 antisense DNA treatment. This antisense DNA, common to both GRK2 and GRK3, also blocked chronic ADR-induced alpha(2A)-AR desensitization and down-regulation. (6) Acute (1 h) ADR (300 nM) or NA treatment (1 micro M) produced alpha(2A)-AR desensitization. The desensitization produced by acute treatment was beta-AR independent, as it was not blocked by propranolol. (7) We conclude that chronic treatment with modest levels of ADR produces alpha(2A)-AR desensitization by mechanisms that involve up-regulation of GRK3 and down-regulation of alpha(2A)-AR levels through interactions with the beta(2)-AR.

Hypoxia-induced down-regulation of CYP1A1/1A2 and up-regulation of CYP3A6 involves serum mediators

1. Acute moderate hypoxia modifies the catalytic activity and expression of certain isoenzymes of hepatic cytochrome P450 (P450). The aim of this study was to document whether hypoxia affects hepatic P450 directly or through the release of serum mediators. 2. Rabbits were subjected to a FiO(2) of 8% for 48 h, sacrificed, and serum and hepatocytes were isolated; hepatocytes from control and rabbits with hypoxia were incubated with serum from control and hypoxic rabbits for 4 and 24 h, and total P450 content, CYP1A1, 1A2 and 3A6 activities and expressions were assessed. Sera were fractionated by size exclusion chromatography and fractions tested for their ability to modify activity and amount of P450, and serum mediators were identified through neutralization experiments. 3. Total serum and fractions with proteins of 15-23 and 65-94 kDa of M(r) reduced P450 content and expression of CYP1A1, 1A2 and 3A6, as well as CYP1A1, 1A2 and 3A6 mRNA. Total serum and the fraction with 32-44 kDa proteins increased CYP3A6 activity and protein and mRNA. The serum mediators implicated in the decrease in activity and expression of CYP1A1, 1A2 and 3A6 were interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta) and IL-2. Erythropoietin (Epo) was partly responsible for the increase in P450 content and CYP3A6 expression. 4. In conclusion, acute moderate hypoxia diminishes the activity and expression of CYP1A1, 1A2 and CYP1A1, 1A2 mRNA, and increases CYP3A6 protein, activity and CYP3A6 mRNA. Several mechanisms contribute to these changes in P450, among them the release of cytokines acting as serum mediators.