Involvement of the KIT/KITL signaling pathway in 4-vinylcyclohexene diepoxide-induced ovarian follicle loss in rats.
Repeated daily dosing of rats with the occupational chemical 4-vinylcyclohexene diepoxide (VCD) depletes the ovary of primordial and primary follicles through an increase in the natural process of atresia. Additionally, in vitro exposure of Postnatal Day 4 (PND 4) rat ovaries to VCD causes similar follicular depletion. This study was designed to investigate survival signaling pathways that may be associated with VCD-induced ovotoxicity in small preantral follicles. Female Fischer 344 rats (PND 28) were dosed daily (80 mg/kg/day VCD i.p.; 12 days in vivo), and PND 4 ovaries were cultured (VCD 20 or 30 microM; 8 days in vitro). Microarray analysis identified a subset of 14 genes whose expression was increased or decreased by VCD in both experiments (i.e., via both exposure routes). Particularly, the analysis showed that relative to controls, VCD did not affect mRNA expression of growth and differentiation factor 9 (Gdf9), whereas there were decreases in mRNA encoding bone morphogenic protein receptor 1a (Bmpr1a) and Kit. To confirm findings from microarray, the genes Gdf9, Bmpr1a, and Kit were further examined. When growth factors associated with these pathways were added to ovarian cultures during VCD exposure, GDF9 and BMP4 had no effect on VCD-induced ovotoxicity; however, KITL attenuated this follicle loss. Additionally, there was a decrease in Kit and an increase in Kitl expression (mRNA and protein) following VCD exposure, relative to control. These results support that VCD compromises KIT/KITL signaling, which is critical for follicular survival in primordial and primary follicles.
Fernandez
Shannon M
SM
Department of Physiology, University of Arizona, Tucson, Arizona 85724, USA.
Keating
Aileen F
AF
Christian
Patricia J
PJ
Sen
Nivedita
N
Hoying
James B
JB
Brooks
Heddwen L
HL
Hoyer
Patricia B
PB
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D055430:Bone Morphogenetic Protein 15; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D053138:Cyclohexenes / Q000494:pharmacology*; D005260:Female; D005496:Follicular Atresia / Q000187:drug effects* / Q000235:genetics*; D020869:Gene Expression Profiling; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D019089:Stem Cell Factor / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D014753:Vinyl Compounds / Q000494:pharmacology*
C525904:Bmp15 protein, rat; C525811:Bmp4 protein, rat; D055430:Bone Morphogenetic Protein 15; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D053138:Cyclohexenes; C525899:Gdf9 protein, rat; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins; D019089:Stem Cell Factor; D014753:Vinyl Compounds; C012606:4-vinyl-1-cyclohexene dioxide; D019009:Proto-Oncogene Proteins c-kit