title: Effects of corticotrophin releasing hormone (CRH) on cell viability and differentiation in the human BeWo choriocarcinoma cell line: a potential syncytialisation inducer distinct from cyclic adenosine monophosphate (cAMP).
abstract: BACKGROUND
  Placental production of corticotrophin releasing hormone (CRH) rises exponentially as pregnancy progresses, and has been linked with the onset of normal and preterm labour. CRH is produced in syncytiotrophoblast cells and production is increased by glucocorticoids and cAMP. It remains unclear whether cAMP acts by inducing differentiation of cytotrophoblasts and/or through induction of syncytialisation. As CRH can stimulate cAMP pathways we have tested whether a feed-forward system may exist in placental cells during syncytialisation.
  
  
  METHODS
  The choriocarcinoma BeWo cell line was treated with cAMP, CRH or vehicle. Cell viability was determined by MTT assay, while apoptosis was analysed by DAPI staining and by FACS. Differentiation was measured by assaying message for hCG and ERVW-1 (syncytin1) by qRT-PCR, as well as the respective protein by ELISA. Fusion of BeWo cells was assessed by co-staining cell membrane and nuclei with CellMask and Hoechst 33342. CRHR1 and CRHR2 mRNA levels were measured by qRT-PCR.
  
  
  RESULTS
  We show that cAMP has an inductive effect on syncytialisation, as evidenced by induction of hCG secretion, by ERVW-1 mRNA expression and by formation of multinuclear cells. CRH mRNA expression was found to increase prior to the changes in the other syncytialisation markers. cAMP had an inhibitory effect on BeWo cell viability, but exogenous CRH did not. However, CRH did mimic the differentiation inducing effect of cAMP, suggesting a link between CRH and cAMP signalling in syncytialisation. We also found that treatment of BeWo cells with exogenous CRH resulted in elevated cellular CRHR1 levels.
  
  
  CONCLUSIONS
  This study suggests a positive feed-forward role exists for CRH in trophoblast cell differentiation, which may underlie the exponential rise in CRH observed as gestation advances.
authors.affiliation: Department of Pathophysiology, Second Military Medical University, Shanghai 200433, China
authors.forename: YuXia
authors.initials: Y
authors.lastname: Chen
authors.forename: Megan
authors.initials: M
authors.lastname: Allars
authors.forename: Xin
authors.initials: X
authors.lastname: Pan
authors.forename: Kaushik
authors.initials: K
authors.lastname: Maiti
authors.forename: Giavanna
authors.initials: G
authors.lastname: Angeli
authors.forename: Roger
authors.initials: R
authors.lastname: Smith
authors.forename: Richard C
authors.initials: RC
authors.lastname: Nicholson
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002459:Cell Fusion; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002822:Choriocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006063:Chorionic Gonadotropin / Q000235:genetics / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D000242:Cyclic AMP / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D015686:Gene Products, env / Q000235:genetics / Q000378:metabolism; D015726:Giant Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000378:metabolism; D018019:Receptors, Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014327:Trophoblasts / Q000187:drug effects* / Q000378:metabolism; D014594:Uterine Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000099052:CRF Receptor, Type 1
chemical_list: C101531:CRF receptor type 2; D006063:Chorionic Gonadotropin; D015686:Gene Products, env; D011257:Pregnancy Proteins; D018019:Receptors, Corticotropin-Releasing Hormone; C405335:syncytin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP