sRAGE downregulates the VEGF expression in OHSS ovarian granulosa cells.

OBJECTIVE: Ovarian hyperstimulation syndrome (OHSS) is mainly caused by human chorionic gonadotropin (hCG) through vasoactive mediators such as vascular endothelial growth factor (VEGF) and various inflammatory factors. Our previous study showed that soluble receptor for advanced glycation end products (sRAGE) played a protective role in PCOS by inhibiting VEGF, so wanted to explore the role of sRAGE in OHSS. METHODS: Two sets of experiments were performed in this study. In part one, sRAGE protein levels in follicular fluid (FF) samples from 60 patients with OHSS and 60 non-OHSS patients were measured by ELISA. In part two, ovarian granulosa cells were isolated from an additional 25 patients with OHSS and cultured. Then, ovarian granulosa cells were treated with different concentrations of sRAGE. Granulosa cells cultured without sRAGE stimulation were used as the control group. The levels of VEGF, amphiregulin (AREG), betacellulin (BTC), and epiregulin (EREG) mRNA were examined by quantitative RT-PCR. The protein levels of VEGF, AREG, BTC, and EREG were measured by ELISA. RESULTS: Compared with non-OHSS patients, patients with OHSS exhibited lower sRAGE levels in both serum and FF (p < .05). Treatment with sRAGE decreased the production of VEGF, and the effects were dependent on the concentration of sRAGE (p < .05). Simultaneously, the expression of the EGF-like growth factors AREG, BTC and EREG was decreased, and their expression was dependent on the concentration of sRAGE (p < .05). CONCLUSIONS: sRAGE downregulate VEGF expression in OHSS ovarian granulosa cells, in which EGF-like growth factor pathway may be involved, and sRAGE may play a potential protective role in OHSS.

Betacellulin regulates peripheral nerve regeneration by affecting Schwann cell migration and axon elongation.

BACKGROUND: Growth factors execute essential biological functions and affect various physiological and pathological processes, including peripheral nerve repair and regeneration. Our previous sequencing data showed that the mRNA coding for betacellulin (Btc), an epidermal growth factor protein family member, was up-regulated in rat sciatic nerve segment after nerve injury, implying the potential involvement of Btc during peripheral nerve regeneration. METHODS: Expression of Btc was examined in Schwann cells by immunostaining. The function of Btc in regulating Schwann cells was investigated by transfecting cultured cells with siRNA segment against Btc or treating cells with Btc recombinant protein. The influence of Schwann cell-secreted Btc on neurons was determined using a co-culture assay. The in vivo effects of Btc on Schwann cell migration and axon elongation after rat sciatic nerve injury were further evaluated. RESULTS: Immunostaining images and ELISA outcomes indicated that Btc was present in and secreted by Schwann cells. Transwell migration and wound healing observations showed that transfection with siRNA against Btc impeded Schwann cell migration while application of exogenous Btc advanced Schwann cell migration. Besides the regulating effect on Schwann cell phenotype, Btc secreted by Schwann cells influenced neuron behavior and increased neurite length. In vivo evidence supported the promoting role of Btc in nerve regeneration after both rat sciatic nerve crush injury and transection injury. CONCLUSION: Our findings demonstrate the essential roles of Btc on Schwann cell migration and axon elongation and imply the potential application of Btc as a regenerative strategy for treating peripheral nerve injury.

Functional and transcriptomic characterization of cisplatin-resistant AGS and MKN-28 gastric cancer cell lines.

Gastric cancer (GC) is a significant cancer-related cause of death worldwide. The most used chemotherapeutic regimen in GC is based on platinum drugs such as cisplatin (CDDP). However, CDDP resistance reduces advanced GC survival. In vitro drug-resistant cell model would help in the understanding of molecular mechanisms underlying this drug-resistance phenomenon. The aim of this study was to characterize new models of CDDP-resistant GC cell lines (AGS R-CDDP and MKN-28 R-CDDP) obtained through a stepwise increasing drug doses method, in order to understand the molecular mechanisms underlying chemoresistance as well as identify new therapeutic targets for the treatment of GC. Cell viability assays, cell death assays and the expression of resistance molecular markers confirmed that AGS R-CDDP and MKN-28 R-CDDP are reliable CDDP-resistant models. RNA-seq and bioinformatics analyses identified a total of 189 DEGs, including 178 up-regulated genes and 11 down-regulated genes, associated mainly to molecular functions involved in CDDP-resistance. DEGs were enriched in 23 metabolic pathways, among which the most enriched was the inflammation mediated by chemokine and cytokine signaling pathway. Finally, the higher mRNA expression of SERPINA1, BTC and CCL5, three up-regulated DEGs associated to CDDP resistance found by RNA-seq analysis was confirmed. In summary, this study showed that AGS R-CDDP and MKN-28 R-CDDP are reliable models of CDDP resistance because resemble many of resistant phenotype in GC, being also useful to assess potential therapeutic targets for the treatment of gastric cancers resistant to CDDP. In addition, we identified several DEGs associated with molecular functions such as binding, catalytic activity, transcription regulator activity and transporter activity, as well as signaling pathways associated with inflammation process, which could be involved in the development of CDDP resistance in GC. Further studies are necessary to clarify the role of inflammatory processes in GC resistant to CDDP and these models could be useful for these purposes.

The endogenous hydrogen sulfide generating system regulates ovulation.

The generation of free-radicals such as nitric oxide has been implicated in the regulation of ovarian function, including ovulation. Tissues that generate nitric oxide typically generate another free-radical gas, hydrogen sulfide (H2S), although little is known about the role of H2S in ovarian function. The hypothesis of this study was that H2S regulates ovulation. Treatment with luteinizing hormone (LH) increased the levels of mRNA and protein of the H2S generating enzyme cystathionine γ-lyase (CTH) in granulosa cells of mice and humans in vivo and in vitro. Pharmacological inhibition of H2S generating enzymes reduced the number of follicles ovulating in mice in vivo and in vitro, and this inhibitory action was reversed by cotreatment with a H2S donor. Addition of a H2S donor to cultured mouse granulosa cells increased basal and LH-dependent abundance of mRNA encoding amphiregulin, betacellulin and tumor necrosis alpha induced protein 6, proteins important for cumulus expansion and follicle rupture. Inhibition of CTH activity reduced abundance of mRNA encoding matrix metalloproteinase-2 and -9 and tissue-type plasminogen activator, and cotreatment with the H2S donor increased the levels of these mRNA above those stimulated by LH alone. We conclude that the H2S generating system plays an important role in the propagation of the preovulatory cascade and rupture of the follicle at ovulation.

Downregulation of microRNA-149 in retinal ganglion cells suppresses apoptosis through activation of the PI3K/Akt signaling pathway in mice with glaucoma.

Glaucoma represents a major cause of blindness, generally associated with elevated intraocular pressure (EIOP). The aim of the present study was to investigate whether microRNA-149 (miR-149) affects retinal ganglion cells (RGCs) and the underlying mechanism based on a mouse model of chronic glaucoma with EIOP. The successfully modeled mice were administered with mimics or inhibitors of miR-149. Next, the number of RGCs, ultrastructural changes of RGCs, and purity of RGCs in the retinal tissues were detected. Moreover, the RGCs were collected and subsequently treated with 60 mmHg pressure and transfected with a series of plasmids aiding in the regulation of the expression of miR-149 and betacellulin (BTC). The levels of miR-149, BTC, phosphatidylinositol 3-kinase (PI3K), and Akt were subsequently determined. Finally, RGC viability and apoptosis were detected accordingly. Dual luciferase reporter gene assay provided validation, highlighting BTC was indeed a target gene of miR-149. The downregulation of miR-149 is accompanied by an increased number of RGCs and decreased ultrastructural RGC alterations. Additionally, downregulated miR-149 was noted to increase the levels of BTC, PI3K, and Akt in both the retinal tissues and RGCs, whereas the silencing of miR-149 was observed to promote the viability of RGC and inhibit RGC apoptosis. Taken together, the results of the current study provided validation suggesting that the downregulation of miR-149 confers protection to RGCs by means of activating the PI3K/Akt signaling pathway via upregulation of BTC in mice with glaucoma. Evidence presented indicated the promise of miR-149 inhibition as a potential therapeutic strategy for glaucoma treatment.

Ligand-Independent Epidermal Growth Factor Receptor Overexpression Correlates with Poor Prognosis in Colorectal Cancer.

PURPOSE: Molecular treatments targeting epidermal growth factor receptors (EGFRs) are important strategies for advanced colorectal cancer (CRC). However, clinicopathologic implications of EGFRs and EGFR ligand signaling have not been fully evaluated. We evaluated the expression of EGFR ligands and correlation with their receptors, clinicopathologic factors, and patients' survival with CRC. MATERIALS AND METHODS: The expression of EGFR ligands, including heparin binding epidermal growth factor-like growth factor (HBEGF), transforming growth factor (TGF), betacellulin, and epidermal growth factor (EGF), were evaluated in 331 consecutive CRC samples using mRNA in situ hybridization (ISH). We also evaluated the expression status of EGFR, human epidermal growth factor receptor 2 (HER2), HER3, and HER4 using immunohistochemistry and/or silver ISH. RESULTS: Unlike low incidences of TGF (38.1%), betacellulin (7.9%), and EGF (2.1%), HBEGF expression was noted in 62.2% of CRC samples. However, the expression of each EGFR ligand did not reveal significant correlations with survival. The combined analyses of EGFR ligands and EGFR expression indicated that the ligands‒/EGFR+ group showed a significant association with the worst disease-free survival (DFS; p=0.018) and overall survival (OS; p=0.005). It was also an independent, unfavorable prognostic factor for DFS (p=0.026) and OS (p=0.007). Additionally, HER4 nuclear expression, regardless of ligand expression, was an independent, favorable prognostic factor for DFS (p=0.034) and OS (p=0.049), by multivariate analysis. CONCLUSION: Ligand-independent EGFR overexpression was suggested to have a significant prognostic impact; thus, the expression status of EGFR ligands, in addition to EGFR, might be necessary for predicting patients' outcome in CRC.

Anti-TCRß mAb in Combination With Neurogenin3 Gene Therapy Reverses Established Overt Type 1 Diabetes in Female NOD Mice.

Insulin-producing ß cells in patients with type 1 diabetes (T1D) are destroyed by T lymphocytes. We investigated whether targeting the T-cell receptor (TCR) with a monoclonal antibody (mAb) abrogates T-cell response against residual and newly formed islets in overtly diabetic nonobese diabetic (NOD) mice. NOD mice with blood glucose levels of 250 to 350 mg/dL or 350 to 450 mg/dL were considered as new-onset or established overt diabetes, respectively. These diabetic NOD mice were transiently treated with an anti-TCR ß chain (TCRß) mAb, H57-597, for 5 days. Two weeks later, some NOD mice with established overt diabetes further received hepatic gene therapy using the islet-lineage determining gene Neurogenin3 (Ngn3), in combination with the islet growth factor gene betacellulin (Btc). We found that anti-TCRß mAb (50 µg/d) reversed >80% new-onset diabetes in NOD mice for >14 weeks by reducing the number of effector T cells in the pancreas. However, anti-TCRß mAb therapy alone reversed only ∼20% established overt diabetes in these mice. Among those overtly diabetic NOD mice whose diabetes was resistant to anti-TCRß mAb treatment, ∼60% no longer had diabetes when they also received Ngn3-Btc hepatic gene transfer 2 weeks after initial anti-TCRß mAb treatment. This combination of Ngn3-Btc gene therapy and anti-TCRß mAb treatment induced the sustained formation of periportal insulin-producing cells in the liver of overtly diabetic mice. Therefore, directly targeting TCRß with a mAb potently reverses new-onset T1D in NOD mice and protects residual and newly formed gene therapy-induced hepatic neo-islets from T-cell‒mediated destruction in mice with established overt diabetes.

Betacellulin regulates schwann cell proliferation and myelin formation in the injured mouse peripheral nerve.

When a nerve fiber is cut or crushed, the axon segment that is separated from the soma degenerates distal from the injury in a process termed Wallerian degeneration (WD). C57BL/6OlaHsd-WldS (WldS ) mutant mice exhibit significant delays in WD. This results in considerably delayed Schwann cell and macrophage responses and thus in impaired nerve regenerations. In our previous work, thousands of genes were screened by DNA microarrays and over 700 transcripts were found to be differentially expressed in the injured sciatic nerve of WldS compared with wild-type (WT) mice. One of these transcripts, betacellulin (Btc), was selected for further analysis since it has yet to be characterized in the nervous system, despite being known as a ligand of the ErbB receptor family. We show that Btc mRNA is strongly upregulated in immature and dedifferentiated Sox2+ Schwann cells located in the sciatic nerve distal stump of WT mice, but not WldS mutants. Transgenic mice ubiquitously overexpressing Btc (Tg-Btc) have increased numbers of Schmidt-Lantermann incisures compared with WT mice, as revealed by Coherent anti-Stokes Raman scattering (CARS). Tg-Btc mice also have faster nerve conduction velocity. Finally, we found that deficiency in Btc reduces the proliferation of myelinating Schwann cells after sciatic nerve injury, while Btc overexpression induces Schwann cell proliferation and improves recovery of locomotor function. Taken together, these results suggest a novel regulatory role of Btc in axon-Schwann cell interactions involved in myelin formation and nerve repair. GLIA 2017 GLIA 2017;65:657-669.

Dibutyl phthalate impairs steroidogenesis and a subset of LH-dependent genes in cultured human mural granulosa cell in vitro.

Exposure to di-butyl phthalate (DBP) exerts negative effects on female fertility in animal models, but human studies remain limited. Here, the effects of DBP exposure on mural granulosa cell function were investigated in primary cultures from women undergoing in vitro fertilization. Cultured cells treated with various doses of DBP (0, 0.01µg/mL, 0.1µg/mL, 1µg/mL, 10µg/mL, or 100µg/mL) for 48h were assessed using enzyme-linked immunosorbent assay and qRT-PCR. Treatment with 100µg/mL DBP resulted in significantly lower 17ß-estradiol and progesterone production (p<0.01). It also resulted in altered mRNA expression of steroidogenic, angiogenic, and epidermal growth factor-like growth factor genes: CYP11A1 (p<0.001), CYP19A1 (aromatase) (p<0.001), VEGF-A (p<0.02), BTC (p=0.009), and EREG (p=0.04). StAR expression was impaired after exposure to both 10 and 100µg/mL (p<0.03 and p<0.001, respectively). Our results indicate that in vitro exposure of granulosa cells to high doses of DBP alters cell functions.

Ephrin-A5 Is Required for Optimal Fertility and a Complete Ovulatory Response to Gonadotropins in the Female Mouse.

Follicle growth and ovulation involve the coordinated expression of many genes, driven by FSH and LH. Reports indicate that Eph receptors and ephrins are expressed in the ovary, suggesting roles in follicle growth and/or ovulation. We previously reported FSH-induced expression of ephrin-A5 (EFNA5) and 4 of its cognate Eph receptors in mouse granulosa cells. We now report that female mice lacking EFNA5 are subfertile, exhibit a compromised response to LH, and display abnormal ovarian histology after superovulation. Efna5(-/-) females litters were 40% smaller than controls, although no difference in litter frequency was detected. The ovarian response to superovulation was also compromised in Efna5(-/-) females, with 37% fewer oocytes ovulated than controls. These results corresponded with a reduction in ovarian mRNA levels of several LH-responsive genes, including Pgr, Ptgs2, Tnfaip6, Ereg, Btc, and Adamts4, suggesting that Efna5(-/-) ovaries exhibit a partially attenuated response to LH. Histopathological analysis indicated that superovulated Efna5(-/-) females exhibited numerous ovarian defects, including intraovarian release of cumulus oocyte complexes, increased incidence of oocytes trapped within luteinized follicles, granulosa cell and follicular fluid emboli, fibrin thrombi, and interstitial hemorrhage. In addition, adult Efna5(-/-) ovaries exhibited a 4-fold increase in multioocyte follicles compared with controls, although no difference was detected in 3-week-old mice, suggesting the possibility of follicle merging. Our observations indicate that loss of EFNA5 in female mice results in subfertility and imply that Eph-ephrin signaling may also play a previously unidentified role in the regulation of fertility in women.

Induction of lateral lumens through disruption of a monoleucine-based basolateral-sorting motif in betacellulin.

Directed delivery of EGF receptor (EGFR) ligands to the apical or basolateral surface is a crucial regulatory step in the initiation of EGFR signaling in polarized epithelial cells. Herein, we show that the EGFR ligand betacellulin (BTC) is preferentially sorted to the basolateral surface of polarized MDCK cells. By using sequential truncations and site-directed mutagenesis within the BTC cytoplasmic domain, combined with selective cell-surface biotinylation and immunofluorescence, we have uncovered a monoleucine-based basolateral-sorting motif (EExxxL, specifically (156)EEMETL(161)). Disruption of this sorting motif led to equivalent apical and basolateral localization of BTC. Unlike other EGFR ligands, BTC mistrafficking induced formation of lateral lumens in polarized MDCK cells, and this process was significantly attenuated by inhibition of EGFR. Additionally, expression of a cancer-associated somatic BTC mutation (E156K) led to BTC mistrafficking and induced lateral lumens in MDCK cells. Overexpression of BTC, especially mistrafficking forms, increased the growth of MDCK cells. These results uncover a unique role for BTC mistrafficking in promoting epithelial reorganization.

Gene therapy with neurogenin3, betacellulin and SOCS1 reverses diabetes in NOD mice.

Islet transplantation for type 1 diabetes is limited by a shortage of donor islets and requirement for immunosuppression. We approached this problem by inducing in vivo islet neogenesis in non-obese diabetic (NOD) diabetic mice, a model of autoimmune diabetes. We demonstrate that gene therapy with helper-dependent adenovirus carrying neurogenin3 (Ngn3), an islet lineage-defining transcription factor, and betacellulin (Btc), an islet growth factor, leads to the induction of periportal insulin-positive cell clusters in the liver, which are rapidly destroyed. To specifically accord protection to these 'neo-islets' from cytokine-mediated destruction, we overexpressed suppressor of cytokine signaling 1 (SOCS1) gene, using a rat insulin promoter in combination with Ngn3 and Btc. With this approach, about half of diabetic mice attained euglycemia sustained for over 4 months, regain glucose tolerance and appropriate glucose-stimulated insulin secretion. Histological analysis revealed periportal islet hormone-expressing 'neo-islets' in treated mouse livers. Despite evidence of persistent 'insulitis' with activated T cells, these 'neo-islets' persist to maintain euglycemia. This therapy does not affect diabetogenicity of splenocytes, as they retain the ability to transfer diabetes. This study thus provides a proof-of-concept for engineering in vivo islet neogenesis with targeted resistance to cytokine-mediated destruction to provide a long-term reversal of diabetes in NOD mice.

Betacellulin ameliorates hyperglycemia in obese diabetic db/db mice.

UNLABELLED: We found that administration of a recombinant adenovirus (rAd) expressing betacellulin (BTC) into obese diabetic db/db mice ameliorated hyperglycemia. Exogenous glucose clearance was significantly improved, and serum insulin levels were significantly higher in rAd-BTC-treated mice than rAd-ß-gal-treated control mice. rAd-BTC treatment increased insulin/bromodeoxyuridine double-positive cells in the islets, and islets from rAd-BTC-treated mice exhibited a significant increase in the level of G1-S phase-related cyclins as compared with control mice. In addition, BTC treatment increased messenger RNA (mRNA) and protein levels of these cyclins and cyclin-dependent kinases in MIN-6 cells. BTC treatment induced intracellular Ca(2+) levels through phospholipase C-γ1 activation, and upregulated calcineurin B (CnB1) levels as well as calcineurin activity. Upregulation of CnB1 by BTC treatment was observed in isolated islet cells from db/db mice. When treated with CnB1 small interfering RNA (siRNA) in MIN-6 cells and isolated islets, induction of cell cycle regulators by BTC treatment was blocked and consequently reduced BTC-induced cell viability. As well as BTC's effects on cell survival and insulin secretion, our findings demonstrate a novel pathway by which BTC controls beta-cell regeneration in the obese diabetic condition by regulating G1-S phase cell cycle expression through Ca(2+) signaling pathways. KEY MESSAGES: Administration of BTC to db/db mice results in amelioration of hyperglycemia. BTC stimulates beta-cell proliferation in db/db mice. Ca(2+) signaling was involved in BTC-induced beta-cell proliferation. BTC has an anti-apoptotic effect and potentiates glucose-stimulated insulin secretion.

Betacellulin transgenic mice develop urothelial hyperplasia and show sex-dependent reduction in urinary major urinary protein content.

The epidermal growth factor (EGF)-like ligands and their cognate ERBB1-4 receptors represent important signaling pathways that regulate tissue and cell proliferation, differentiation and regeneration in a wide variety of tissues, including the urogenital tract. Betacellulin (BTC) can activate all four ERBB tyrosine kinase receptors and is a multifunctional EGF-like ligand with diverse roles in ß cell differentiation, bone maturation, formation of functional epithelial linings and vascular permeability in different organs. Using transgenic BTC mice, we have studied the effect of constitutive systemic BTC over-expression on the urinary bladder. BTC was detected in microvascular structures of the stromal bladder compartment and in umbrella cells representing the protective apical lining of the uroepithelium. ERBB1 and ERBB4 receptors were co-localized in the urothelium. Mice transgenic for BTC and double transgenic for both BTC and the dominant kinase-dead mutant of EGFR (Waved 5) developed hyperplasia of the uroepithelium at 5months of age, suggesting that urothelial hyperplasia was not exclusively dependent on ERBB1/EGFR. Mass spectrometric analysis of urine revealed a significant down-regulation of major urinary proteins in female BTC transgenic mice, suggesting a novel role for systemic BTC in odor-based signaling in female transgenic BTC mice.

Nerve growth factor neutralization suppresses ß-cell proliferation through activin A and betacellulin.

OBJECTIVE: The aim of this study was to investigate the effects of nerve growth factor (NGF) neutralization on synthesis and secretion of activin A (Act-A) and betacellulin (BTC) from primary ß cells and the importance of these relations for ß-cell proliferation. METHODS: ß Cells were isolated from euglycemic and streptozotocin-induced (75 mg/kg) hyperglycemic rats and treated with NGF neutralization antibody. The gene expression levels of Act-A and BTC in the primary ß cells were evaluated using quantitative real-time polymerase chain reaction. The cellular and secreted levels of Act-A and BTC proteins were estimated using Western blot analysis. RESULTS: Nerve growth factor neutralization (1) reduced ß-cell proliferation, (2) decreased Act-A at gene expression and protein levels while increasing its secretion from ß cells, and (3) increased BTC at gene expression level while mildly decreasing its cellular protein level and secretion from ß cells. Nerve growth factor neutralization specifically affected ß cells of hyperglycemic rats. CONCLUSIONS: These findings indicate that NGF is an important regulator for the synthesis and secretion of Act-A and BTC from the ß cells. Moreover, the results suggested that ß-cell proliferation decreased through NGF neutralization is possibly related to decreased BTC and increased Act-A secretion from ß cells of hyperglycemic rats.

The ABC of BTC: structural properties and biological roles of betacellulin.

Betacellulin was initially detected as a growth-promoting factor in the conditioned medium of a mouse pancreatic ß-cell tumor cell line. Sequencing of the purified protein and of the cloned cDNA supported the assumption that betacellulin is a new ligand of the epidermal growth factor receptor (EGFR), which was later confirmed experimentally. As a typical EGFR ligand, betacellulin is expressed by a variety of cell types and tissues, and the soluble growth factor is proteolytically cleaved from a larger membrane-anchored precursor. Importantly, BTC can - in addition to the EGFR - bind and activate all possible heterodimeric combinations of the related ERBB receptors including the highly oncogenic ERBB2/3 dimer, as well as homodimers of ERBB4. While a large number of studies attest a role for betacellulin in the differentiation of pancreatic ß-cells, the last decade witnessed the association of betacellulin with a large number of additional biological processes, ranging from reproduction to the control of neural stem cells.