title: Protein expression of PKCZ (Protein Kinase C Zeta), Munc18c, and Syntaxin-4 in the insulin pathway in endometria of patients with polycystic ovary syndrome (PCOS).
abstract: BACKGROUND
  Polycystic Ovary Syndrome (PCOS) is an endocrine-metabolic disorder commonly associated with insulin resistance (IR). Previous studies indicate about the expression of molecules involved in the insulin pathway in endometria of women with PCOS-IR. Therefore, the aim of the present study was to evaluate the effect of insulin and testosterone in the expression of these proteins in the endometria and immortal endometrial stromal cell line (T-HESCs).
  
  
  METHODS
  We examined the protein levels of Munc18c, PKC zeta, phospho-PKC Zeta, and Syntaxin-4. Protein levels were assessed by Western Blot and/or immunohistochemistry in proliferative endometria (NPE = 6) and in PCOS endometria with insulin resistance (PCOSE-IR = 6). We also evaluated whether high concentrations of insulin (100 nM) and/or testosterone (100 nM), during a 24 h stimulatory period, affected the expression of these proteins in an immortal endometrial stromal cell line (T-HESCs). Once stimulated, proteins were extracted from cells and were assessed by Western Blot analysis. Immunocytochemistry was performed to detect AR in T-HESC cells.
  
  
  RESULTS
  Western Blot data showed decreased expression (p < 0,05) of Munc18c and phospho-PKC Zeta in PCOS-IR endometria (PCOSE-IR) with respect to the control (NPE). In the in vitro study, Western Blot analysis showed decreased levels of Munc18c, PKC Zeta and phospho-PKC Zeta with the different hormonal treatments when compared to the control condition (no hormonal stimulation) (p < 0,05). The AR was present in the endometrial stromal cell line (T-HESC).
  
  
  CONCLUSIONS
  The conditions of hyperinsulinism and hyperandrogenism present in PCOS-IR patients modulate the expression and/or phosphorylation of the proteins involved in the insulin pathway at the endometrial level. These data extend to the T-HESCs cells results, where insulin and testosterone exert an effect on both the expression and phosphorylation of proteins present in the pathway.
authors.affiliation: Endocrinology and Reproductive Biology Laboratory, Clinical Hospital University of Chile (HCUCH), Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Rivero
authors.forename: Claire-Alix
authors.initials: CA
authors.lastname: Garin
authors.forename: Paulina
authors.initials: P
authors.lastname: Ormazabal
authors.forename: Andrea
authors.initials: A
authors.lastname: Silva
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Carvajal
authors.forename: Fernando
authors.initials: F
authors.lastname: Gabler
authors.forename: Carmen
authors.initials: C
authors.lastname: Romero
authors.forename: Margarita
authors.initials: M
authors.lastname: Vega
mesh_terms: D000328:Adult; D002460:Cell Line; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D051938:Munc18 Proteins / Q000096:biosynthesis*; D011085:Polycystic Ovary Syndrome / Q000378:metabolism*; D011493:Protein Kinase C / Q000096:biosynthesis*; D050765:Qa-SNARE Proteins / Q000096:biosynthesis*; D011944:Receptors, Androgen / Q000096:biosynthesis; D000099221:Protein Kinase C zeta
chemical_list: D007328:Insulin; D051938:Munc18 Proteins; D011493:Protein Kinase C; D050765:Qa-SNARE Proteins; D011944:Receptors, Androgen; D000099221:Protein Kinase C zeta