Cytoplasmic and nuclear STAT3 in GH-stimulated fibroblasts of children with idiopathic short stature.
BACKGROUND
STAT5, which plays an important role in GH signal transduction, has been studied extensively in children with growth retardation, but there is scarce information regarding STAT3.


OBJECTIVE
We determined total and phosphorylated STAT3 after GH stimulation in fibroblasts from children with idiopathic short stature (ISS) and control children with normal stature.


METHODS
We studied 15 prepubertal children (age 7.6 ± 0.4 years) with short stature (height -2.8 ± 0.2 SDS), decreased growth velocity (<p10), a GH response of >10 ng/ml to the clonidine stimulation test and decreased serum IGF-I concentrations (<-1 SDS), and 19 control children with normal stature (age 6.7 ± 0.3 years). We determined the levels of total and phosphorylated STAT3 in the cytoplasmic and nuclear fractions of fibroblast cultures obtained from a skin biopsy, stimulated with GH (200 ng/ml) for 15-60 min.


RESULTS
We observed a reduction in nuclear pSTAT3 levels and a lower nuclear/cytoplasmic STAT3 phosphorylated ratio in 3 patients from the study group compared to the control children.


CONCLUSIONS
These results suggest that some children with ISS may exhibit a reduction in the nuclear content of their phosphorylated STAT3.
Martínez Pinto
Jonathan
J
Salazar
Teresa
T
Ocaranza
Paula
P
Fuentes
Ariel
A
Román
Rossana
R
Cassorla
Fernando
F
D000465:Algorithms; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003593:Cytoplasm / Q000378:metabolism*; D015536:Down-Regulation; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006130:Growth Disorders / Q000378:metabolism*; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D008297:Male; D010766:Phosphorylation; D021381:Protein Transport; D011994:Recombinant Proteins; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D012867:Skin / Q000166:cytology / Q000378:metabolism; D013997:Time Factors
D011994:Recombinant Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D019382:Human Growth Hormone