Androgen Excess Increases Food Intake in a Rat Polycystic Ovary Syndrome Model by Downregulating Hypothalamus Insulin and Leptin Signaling Pathways Preceding Weight Gain.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common reproductive and metabolic disorder characterized by high androgen levels. The aim of this study was to evaluate the effects of hyperandrogenism on the hypothalamus and subsequently on the food intake and obesity in females. METHODS: A dihydroxy testosterone (DHT)-induced rat model was established to recapitulate the hyperandrogenism features of PCOS patients. Body weight and food intake of the rats were recorded. The food intake of DHT-induced rats was restricted by pair feeding to exclude possible effects of weight gain on the hypothalamus. The expression levels of relevant proteins and mRNAs in the hypothalamus and primary hypothalamic neurons exposed to DHT were analyzed by Western blotting and RT-PCR, respectively. The leptin levels in the serum and cerebrospinal fluid (CSF) were measured, and leptin was injected via the intracerebroventricular (ICV) route to test the leptin sensitivity of the hypothalamus. RESULTS: The excessive prepuberty androgen levels in the DHT-induced rats markedly elevated food intake prior to weight gain. Consistent with this, the expression of neuropeptide Y and agouti-related peptide mRNAs was upregulated, which occurred prior to obesity and even with restricted food intake. In addition, the hypothalamic sensitivity to insulin and leptin was also impaired in the DHT-induced rats before obesity and with restricted food intake. DHT significantly reduced the leptin levels in the CSF, and ICV injection of leptin inhibited the DHT-induced increase in food intake. CONCLUSIONS: Androgen excess increased food intake in rats and promoted obesity by downregulating insulin and leptin signaling in the hypothalamus, most likely by suppressing leptin levels in the CSF.

Involvement of kisspeptin in androgen-induced hypothalamic endoplasmic reticulum stress and its rescuing effect in PCOS rats.

Endoplasmic reticulum (ER) stress, with adaptive unfolded protein response (UPR), is a key link between obesity, insulin resistance and type 2 diabetes, all of which are often present in the most common endocrine-metabolic disorder in women of reproductive age, polycystic ovary syndrome (PCOS), which is characterized with hyperandrogenism. However, the link between excess androgen and endoplasmic reticulum (ER) stress/insulin resistance in patients with polycystic ovary syndrome (PCOS) is unknown. An unexpected role of kisspeptin was reported in the regulation of UPR pathways and its involvement in the androgen-induced ER stress in hypothalamic neuronal cells. To evaluate the relationship of kisspeptin and ER stress, we detected kisspeptin and other factors in blood plasm of PCOS patients, rat models and hypothalamic neuronal cells. We detected higher testosterone and lower kisspeptin levels in the plasma of PCOS than that in non-PCOS women. We established a PCOS rat model by dihydrotestosterone (DHT) chronic exposure, and observed significantly downregulated kisspeptin expression and activated UPR pathways in PCOS rat hypothalamus compared to that in controls. Inhibition or knockdown of kisspeptin completely mimicked the enhancing effect of DHT on UPR pathways in a hypothalamic neuronal cell line, GT1-7. Kp10, the most potent peptide of kisspeptin, effectively reversed or suppressed the activated UPR pathways induced by DHT or thapsigargin, an ER stress activator, in GT1-7 cells, as well as in the hypothalamus in PCOS rats. Similarly, kisspeptin attenuated thapsigargin-induced Ca2+ response and the DHT- induced insulin resistance in GT1-7 cells. Collectively, the present study has revealed an unexpected protective role of kisspeptin against ER stress and insulin resistance in the hypothalamus and has provided a new treatment strategy targeting hypothalamic ER stress and insulin resistance with kisspeptin as a potential therapeutic agent.

Hypoxia-induced and HIF1α-VEGF-mediated tight junction dysfunction in choriocarcinoma cells: Implications for preeclampsia.

INTRODUCTION: Accumulated data indicate that placental hypoxia is implicated in the pathogenesis of preeclampsia (PE). Tight junction (TJ) is important structure that sustains normal placental barrier function, its dysregulation under hypoxia has been observed. This study was designed to explore hypoxia-induced TJ dysfunction in trophoblast cells and its possible involvement in PE pathophysiology. METHODS: Choriocarcinoma cells were grown in a monolayer and treated with cobalt chloride (CoCl2) to induce hypoxia. TJ architecture was assessed using transmission electron microscopy, and locations of TJ proteins were determined by immunofluorescence. TJ functions were assessed by transepithelial electrical resistance (TER) and increased cell paracellular permeability (CPP), and the expression of TJ-related proteins, HIF-1α and VEGF was measured. RESULTS: The TJ functions of trophoblast cells were significantly altered by hypoxia; TER decreased and CPP increased in a time- and concentration-dependent manner. Significant alterations in TJ protein expression and increases in HIF1α and VEGF expression were observed in hypoxic cells, and these effects were attenuated by pretreatment with YC-1. Moreover, corresponding changes in TJ protein expression were also detected in preeclamptic placentas. CONCLUSION: These data demonstrate that trophoblast cells undergo significant changes in TJ protein expression under hypoxic conditions and highlight the potential significance of the HIF1α-VEGF axis in the regulation of TJ structure and function in the preeclamptic placenta.

Effect of neurological monitoring in postoperative 5-15 days residual thyroidectomy after primary thyroid cancer surgery.

AIM: To explore the application of intraoperative neurological monitoring in residual thyroidectomy 5-15 days after thyroid cancer operation and the influence on postoperative serum thyroglobulin (Tg), recurrent laryngeal nerve and function of parathyroid glands. METHODS: Material of patients receiving thyroid surgery from January 2010 to December 2016 was retrospectively analyzed. Cases meeting with standards were enrolled for analysis and the patients were divided into neurological monitoring group and non-neurological monitoring group in line with the use of neurological monitoring during the operation. Recurrent laryngeal nerve-injured hoarseness, hypoparathyroidism and concentration of serum Tg before and after the surgery were collected and analyzed. RESULTS: Four-hundred and thirty-five patients met with standards, among which 227 from neurological monitoring group and 208 from non-neurological monitoring group. Temporary hoarseness rate of non-neurological monitoring group and neurological monitoring group was 8.67% and 2.2%. Permanent hoarseness rate of non-neurological monitoring group and neurological monitoring group was 1.92% and 0.44%. Temporary hypoparathyroidism rate of non-neurological monitoring group and neurological monitoring group was 18.75% and 7.48%. Permanent hypoparathyroidism rate of non-neurological monitoring group and neurological monitoring group was 1.92% and 0.88%. Average Tg concentration 1 month after the surgery in non-neurological monitoring group and neurological monitoring group was 2.82 and 1.37 ng/mL, respectively. Rate of average Tg concentration less than 1 ng/mL 1 month after the surgery in non-neurological monitoring group and neurological monitoring group was 45.06% and 67.4%. CONCLUSION: Intraoperative neurological monitoring can be adopted in residual thyroidectomy in postoperative 5-15 days after primary thyroid cancer surgery, as to reduce incidence rate of recurrent laryngeal nerve injury and hypoparathyroidism and to enhance thorough removal of thyroid tissues and cancer tissues.

Abnormal CFTR Affects Glucagon Production by Islet α Cells in Cystic Fibrosis and Polycystic Ovarian Syndrome.

Glucagon, produced by islet α cells, functions to increase blood glucose. Abnormal glucose levels are often seen in cystic fibrosis (CF), a systematic disease caused by mutations of the CF transmembrane conductance regulator (CFTR), and in polycystic ovarian syndrome (PCOS), an endocrine disorder featured with hyperandrogenism affecting 5-10% women of reproductive age. Here, we explored the role of CFTR in glucagon production in α cells and its possible contribution to glucagon disturbance in CF and PCOS. We found elevated fasting glucagon levels in CFTR mutant (DF508) mice compared to the wildtypes. Glucagon and prohormone convertase 2 (PC2) were also upregulated in CFTR inhibitor-treated or DF508 islets, as compared to the controls or wildtypes, respectively. Dihydrotestosterone (DHT)-induced PCOS rats exhibited significantly lower fasting glucagon levels with higher CFTR expression in α cells compared to that of controls. Treatment of mouse islets or αTC1-9 cells with DHT enhanced CFTR expression and reduced the levels of glucagon and PC2. The inhibitory effect of DHT on glucagon production was blocked by CFTR inhibitors in mouse islets, and mimicked by overexpressing CFTR in αTC1-9 cells with reduced phosphorylation of the cAMP/Ca2+ response element binding protein (p-CREB), a key transcription factor for glucagon and PC2. These results revealed a previously undefined role of CFTR in suppressing glucagon production in α-cells, defects in which may contribute to glucose metabolic disorder seen in CF and PCOS.

Bronchial hyperresponsiveness and obesity in middle age: insights from an Australian cohort.

The association between obesity and bronchial hyperresponsiveness (BHR) is incompletely characterised. Using the 2006 follow-up of the Tasmanian Longitudinal Health Study, we measured the association between obesity and BHR and whether it was mediated by small airway closure or modified by asthma and sex of the patient.A methacholine challenge measured BHR. Multivariable logistic regression measured associations between body mass index (BMI) and BHR, adjusting for sex, asthma, smoking, corticosteroid use, family history and lung function. Mediation by airway closure was also measured.Each increase in BMI of 1 kg·m-2 was associated with a 5% increase in the odds of BHR (OR 1.05, 95% CI 1.01-1.09) and 43% of this association was mediated by airway closure. In a multivariable model, BMI (OR 1.06, 95% CI 1.00-1.16) was associated with BHR independent of female sex (OR 3.26, 95% CI 1.95-5.45), atopy (OR 2.30, 95% CI 1.34-3.94), current asthma (OR 5.74, 95% CI 2.79-11.82), remitted asthma (OR 2.35, 95% CI 1.27-4.35), low socioeconomic status (OR 2.11, 95% CI 1.03-4.31) and forced expiratory volume in 1 s/forced vital capacity (OR 0.86, 95% CI 0.82-0.91). Asthma modified the association with an increasing probability of BHR as BMI increased, only in those with no or remitted asthma.An important fraction of the BMI/BHR association was mediated via airway closure. Conflicting findings in previous studies could be explained by failure to consider this intermediate step.

Involvement of small G protein RhoB in the regulation of proliferation, adhesion and migration by dexamethasone in osteoblastic cells.

Long-term exposure to therapeutic doses of glucocorticoids (GCs) results in bone remodeling, which frequently causes osteoporosis and fracture healing retardation because of the abnormality of osteoblastic proliferation and differentiation. The mechanisms of GCs' effect on osteoblasts are largely unknown. In this present study, we found that dexamethasone (Dex) could induce the expression of the small G protein, RhoB, in mRNA and protein levels in the osteoblast-derived osteosarcoma cell lines MG-63. The up-regulation of RhoB mRNA by Dex mainly occurs at posttranscriptional level by increasing its mRNA stability through PI-3K/Akt and p38 mitogen-activated protein kinase signaling pathways. Over-expression of RhoB in MG-63 cells magnified while down-regulation of RhoB level by RNA interference impaired Dex-induced growth inhibition but not differentiation. What's more, over-expression of RhoB mimicked the effect of Dex on cell adhesion and migration. And interfering RhoB expression partially suppressed Dex-induced pro-adhesion and anti-migration in MG-63 cells. In conclusion, these results indicate that RhoB plays an important role in the pathological effect of Dex on osteoblastic growth and migration, which is a part of the mechanisms of GCs' adverse effect on bone remodeling.

Effect of HSP10 on apoptosis induced by testosterone in cultured mouse ovarian granulosa cells.

OBJECTIVE: To investigate the effect of heat shock protein 10 (HSP10) on apoptosis induced by testosterone in granulosa cells (GCs) of mouse ovaries in order to define the possible roles of HSP10 in ovarian pathological development of polycystic ovarian syndrome (PCOS) and hyperandrogenic conditions. STUDY DESIGN: Cultured mouse ovarian GCs were treated with testosterone (10(-5) mol/l). Apoptosis was assessed using flow cytometry, and proliferation was assessed using the MTT assay. HSP10 expression in the treated GCs was detected by real-time polymerase chain reaction (PCR). HSP10 gene was downregulated in the cultured GCs by AdCMV-H1-SiRNA/HSP10 or overexpressed by AdCMV-HSP10. PD98059 [phosphorylated ERK (p-ERK) inhibitor] was used to treat GCs to induce a high apoptosis index. Critical apoptotic factors and proliferation factors, including P-ERK, Bcl-2, Bax, caspase 9, caspase 3 and Ki67, were monitored by real-time reverse transcriptase PCR (RT-PCR) and Western blot. RESULTS: Compared with the control group, the apoptosis index was higher (p<0.05) and HSP10 expression was lower (p<0.05) in the testosterone-treated groups. In the AdCMV-H1-SiRNA/HSP10-treated group, cell viability was decreased (p<0.05) and the cell cycle was arrested at G2. Expression of p-ERK, Bcl-2 and Ki67, and the Bcl-2:Bax ratio were lower, while expression of apoptotic factors, including Bax, caspase 9 and caspase 3, was higher (p<0.05). Compared with the control group, Bcl-2 expression in the GCs that overexpressed HSP10 was increased (p<0.05), while the reduction of p-ERK and Bcl-2 and the elevation of caspase 9 and caspase 3 induced by PD98059 were significantly suppressed (p<0.05). CONCLUSIONS: Hyperandrogenic conditions induced apoptosis of mouse GCs. Testosterone may have reduced HSP10 expression in GCs, leading to reduced Bcl-2 expression and increased Bax expression.

Up-regulation of stomatin expression by hypoxia and glucocorticoid stabilizes membrane-associated actin in alveolar epithelial cells.

Stomatin is an important lipid raft-associated protein which interacts with membrane proteins and plays a role in the membrane organization. However, it is unknown whether it is involved in the response to hypoxia and glucocorticoid (GC) in alveolar epithelial cells (AEC). In this study we found that hypoxia and dexamethasone (dex), a synthetic GC not only up-regulated the expression of stomatin alone, but also imposed additive effect on the expression of stomatin in A549 cells, primary AEC and lung of rats. Then we investigated whether hypoxia and dex transcriptionally up-regulated the expression of stomatin by reporter gene assay, and found that dex, but not hypoxia could increase the activity of a stomatin promoter-driven reporter gene. Further deletion and mutational studies demonstrated that a GC response element (GRE) within the promoter region mainly contributed to the induction of stomatin by dex. Moreover, we found that hypoxia exposure did not affect membrane-associated actin, but decreased actin in cytoplasm in A549 cells. Inhibiting stomatin expression by stomatin siRNA significantly decreased dense of peripheral actin ring in hypoxia or dex treated A549 cells. Taken all together, these data indicated that dex and/or hypoxia significantly up-regulated the expression of stomatin in vivo and in vitro, which could stabilize membrane-associated actin in AEC. We suppose that the up-regulation of stomatin by hypoxia and dex may enhance the barrier function of alveolar epithelia and mediate the adaptive role of GC to hypoxia.

RhoB is involved in lipopolysaccharide-induced inflammation in mouse in vivo and in vitro.

Small GTPase RhoB has been well documented in regulating cell adhesion, motility, proliferation, and survival, but to date, there is little information about the relationship between RhoB and inflammation. In this study, the mRNA and protein levels of RhoB were induced by lipopolysaccharide (LPS) in RAW264.7 cells determined by real-time PCR and Western blot. The upregulation of RhoB by LPS was also observed in mouse peritoneal macrophages and in mouse lung, liver, and kidney. RhoB overexpression by transfecting with wild RhoB plasmid increased the secretion of tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) in RAW264.7 cells, while RhoB knockdown by RNA interference decreased the secretion of TNF-α and NO in RAW264.7 cells. TNF-α and NO synthase are the target genes of nuclear factor-kappaB (NF-κB), and overexpression of RhoB increased, whereas inhibition of RhoB decreased the basal and LPS-activated transcriptional activity of NF-κB in the cells. These results demonstrated that LPS induced RhoB expression in mouse in vivo and in vitro and in RAW264.7 cells, and the role of RhoB on LPS-induced secretion of TNF-α and NO was at least partly mediated via NF-κB. These results indicated that RhoB was involved in LPS-induced inflammation in mouse in vivo and in vitro.

Therapeutic effects of inhaling aerosolized surfactant alone or with dexamethasone generated by a novel noninvasive apparatus on acute lung injury in rats.

BACKGROUND: Pulmonary surfactant (PS) administration has been attempted for the treatment of adults with acute lung injury (ALI)/adult respiratory distress syndrome. Aerosolized surfactants inhaled by spontaneous breathing may be an effective method of surfactant-based therapies. Using a noninvasive apparatus, we evaluated the therapeutic effects of aerosolized PS alone or together with dexamethasone (Dex) on a rat model of ALI. METHODS: Severe ALI was induced by intravenous injection of 20% oleic acid (0.2 mL/kg) into adult Sprague-Dawley rats. Animals were divided into eight groups: sham (n = 10); model (injury only, n = 10); normal saline (NS) aerosol driven by compressed air (air-NS, n = 13); PS aerosol driven by compressed air (air-PS, n = 13); NS aerosol driven by O2 (O2-NS, n = 13); PS aerosol driven by O2 (O2-PS, n = 13); Dex aerosol driven by O2 (O2-Dex, n = 13); and PS and Dex aerosol driven by O2 (O2-PS-Dex, n = 13). Blood gases, breathing rate, lung index, total protein, and proinflammatory cytokines (tumor necrosis factor-α, interleukin 1ß, interleukin 6) in the bronchoalveolar lavage fluid (BALF), and lung histology were examined. RESULTS: Animals treated with air-PS for 20 minutes had significantly improved lung function, reduced pulmonary edema, decreased concentration of total protein and proinflammatory cytokines in BALF, ameliorated lung injury, and improved animal survival. In the O2-PS group, the breathing rates and lung injury scores were significantly lower than that of the air-PS group. In the O2-PS-Dex group, lung edema, total protein, and inflammatory cytokines in BALF were significantly reduced in comparison with the O2-PS group. CONCLUSION: Inhalation of aerosolized PS generated by the noninvasive apparatus could significantly reduce lung injury, while using oxygen line available in the clinical wards to generate PS aerosol is more convenient and adds further benefits. This method can also be used to deliver Dex and other therapeutic agents to ameliorate lung injury.

[Correlation between serum progesterone level at the day with human chorionic gonadotrophin administration and the outcome of pregnancy in in-vitro fertilization].

OBJECTIVE: To investigate the relationship between serum progesterone level at the day with human chorionic gonadotrophin (hCG) administration and pregnant outcome from in in-vitro fertilization-embryo transfer (IVF-ET). METHODS: From Mar. 2002 to Apr. 2007, 786 cycles with serum progesterone measurement on the day of hCG administration for final oocyte maturation in IVF were analyzed retrospectively in Reproductive Medicine Center in First Affiliated Hospital of Nanjing Medical University. All stimulations were down-regulated with gronadotrophin release hormone agonist (GnRH-a) in both long protocols and short protocols before gonadotrophin stimulation. When the thresholds of serum progesterone were set at 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5 and 9.0 nmol/L, respectively. If the level of progesterone was less than the thresholds, those patients were in lower progesterone group, on the contrary, more than the threshold value, those patients were in higher progesterone group. The laboratory results and the clinical outcomes between all patients at lower and higher progesterone group at different thresholds value were analyzed. RESULTS: The rate of normal fertilization, quality embryos, successful implantation, chemical pregnancy, clinical pregnancy and live birth did not exhibit remarkable difference between patients with higher and lower serum progesterone level at multiple thresholds on the day of hCG administration in the 786 cycles (P > 0.05). However, when the thresholds of serum progesterone were at 8.5 and 9.0 nmol/L, early abortion rates of 27.3% (3/11) and 3/7 in higher progesterone group were significantly higher than 8.8% (26/297) and 8.6% (26/301) in lower progesterone group (P < 0.05). And the total abortion rates of 3/7 in higher progesterone group were significantly higher than 11.0% (34/301) in lower progesterone group when the thresholds of serum progesterone were 9.0 nmol/L (P < 0.05). CONCLUSIONS: This study did not prove the correlationship between progesterone level at the day with hCG administration and the probability of clinical pregnancy or live birth. However, early abortion rates or the total abortion rates were associated with higher progesterone level when the thresholds of serum progesterone were at 8.5 nmol/L or 9.0 nmol/L.

The orphan nuclear receptor NR4A1 regulates transcription of key steroidogenic enzymes in ovarian theca cells.

Orphan nuclear receptor NR4A1, a member of the nuclear receptor superfamily, is widely expressed in different cell types and mediates diverse biological processes. Recent emerging evidence suggests that NR4A1 is involved in the transcriptional regulation of several steroidogenic enzyme genes in gonads and adrenals. However, its function in ovarian theca cells remains to be defined. In the present study, immunohistochemical staining of NR4A1 in healthy human ovaries indicate that it is expressed in theca cells and granulosa cells. In an effort to explore the function of NR4A1 in the transcript regulation of steroidogenic enzyme genes responsible for ovarian theca cell steroidogenesis, we constructed recombinant adenovirus AdCMV-NR4A1 and AdH1-NR4A1 to enhance or knockdown the expression of NR4A1 in theca cells, respectively. The expression patterns of StAR, CYP11A1, CYP17 and HSD3B2 were subsequently analyzed by real-time RT-PCR. Moreover, concentrations of testosterone in the spent medium were measured by radioimmunoassay. Our results show that overexpression of NR4A1 in theca cells stimulates the expression of StAR, CYP11A1, CYP17 and HSD3B2, leading to increased testosterone production. Conversely, knockdown of the endogenous NR4A1 exhibits a significant decrease in StAR, CYP11A1, CYP17 and HSD3B2 expression and testosterone production. Since expression of NR4A1 in the endocrine organs is known to be regulated by both cAMP/PKA mediated hormones, ACTH and LH, forskolin (FSK), an activator of cAMP/PKA pathway, was applied to the cultured follicles. FSK rapidly increases the NR4A1 mRNA levels followed by an increase in StAR, CYP11A1, CYP17 and HSD3B2. Collectively, our results outline a previously unrecognized role for NR4A1 in the transcriptional regulation of StAR, CYP11A1, CYP17 and HSD3B2 in ovarian theca cells. Modulation of these steroidogenic enzymes by NR4A1 could influence the capacity of the ovarian theca cells to produce androgen.

Expression of Gli1 correlates with the transition of breast cancer cells to estrogen-independent growth.

The failure of breast cancer treatment is largely due to the development of estrogen independence. Current data illustrate that Hedgehog (Hh) signaling may play an important role in breast cancer development. Here, we show that the expression of the Hh effector protein, Gli1 was significantly higher in estrogen-independent breast cancer cells than in estrogen-dependent cells. Our data showed for the first time that stable expression of Gli1 in ER positive breast cancer cell lines MCF-7 and T47D can induce estrogen-independent proliferation and promote G1/S phase transition, which associated with cyclin-Rb axi. Gli1 can also attenuate the response of proliferation to estrogenic stimulation, which was correlated with down-regulation of expression of ERalpha and PR, as well as down-regulation of transactivation of ERalpha. Our results suggest that up-regulation of Gli1 in breast cancer cells may be one of the mechanisms responsible for developing estrogen independence and this process may be regulated through down-regulation of expression and transactivation of ERalpha.

Dexamethasone enhances cell resistance to chemotherapy by increasing adhesion to extracellular matrix in human ovarian cancer cells.

Glucocorticoids (GCs) are widely used as co-medication in the therapy of solid malignant tumors to relieve some of the side effects of chemotherapeutic drugs. However, recent studies have shown that GCs could render cancer cells more resistant to cytotoxic drug-induced apoptosis, but the mechanism is largely unknown. In the present study, we found that the treatment of human ovarian cancer cell lines HO-8910 and SKOV3 with synthetic GCs dexamethasone (Dex) significantly increased their adhesion to extracellular matrix (ECM) and their resistance to apoptosis induced by cytotoxic drugs cisplatin and paclitaxel. Dex also increased the protein levels of adhesion molecules integrins beta1, alpha 4, and alpha 5 in HO-8910 cells. The neutralizing antibody against integrin beta1 prevented Dex-induced adhesion and significantly abrogated the protective effect of Dex toward cytotoxic agents. We further found that transforming growth factor-beta1 (TGF-beta1) alone not only increased cell adhesion and cell survival of HO-8910 cells in the presence of cisplatin, but also had synergistic pro-adhesion and pro-survival effects with Dex. Moreover, TGF-beta1-neutralizing antibody that could block TGF-beta1-induced cell adhesion and apoptosis resistance markedly abrogated the synergistic pro-adhesion and pro-survival effects of Dex and TGF-beta1. Finally, we further demonstrated that Dex could up-regulate the expression of TGF-beta receptor type II and enhance the responsiveness of cells to TGF-beta1. In conclusion, our results indicate that increased adhesion to ECM through the enhancement of integrin beta1 signaling and TGF-beta1 signaling plays an important role in chemoresistance induced by GCs in ovarian cancer cells.

REUL is a novel E3 ubiquitin ligase and stimulator of retinoic-acid-inducible gene-I.

RIG-I and MDA5 are cytoplasmic sensors that recognize different species of viral RNAs, leads to activation of the transcription factors IRF3 and NF-kappaB, which collaborate to induce type I interferons. In this study, we identified REUL, a RING-finger protein, as a specific RIG-I-interacting protein. REUL was associated with RIG-I, but not MDA5, through its PRY and SPRY domains. Overexpression of REUL potently potentiated RIG-I-, but not MDA5-mediated downstream signalling and antiviral activity. In contrast, the RING domain deletion mutant of REUL suppressed Sendai virus (SV)-induced, but not cytoplasmic polyI:C-induced activation of IFN-beta promoter. Knockdown of endogenous REUL by RNAi inhibited SV-triggered IFN-beta expression, and also increased VSV replication. Full-length RIG-I, but not the CARD domain deletion mutant of RIG-I, underwent ubiquitination induced by REUL. The Lys 154, 164, and 172 residues of the RIG-I CARD domain were critical for efficient REUL-mediated ubiquitination, as well as the ability of RIG-I to induce activation of IFN-beta promoter. These findings suggest that REUL is an E3 ubiquitin ligase of RIG-I and specifically stimulates RIG-I-mediated innate antiviral activity.