TY - JOUR
T1 - Developmental changes in proximal tubule tight junction proteins
AU - Haddad, Maha
AU - Lin, Fangming
AU - Dwarakanath, Vangipuram
AU - Cordes, Kimberly
AU - Baum, Michel
PY - 2005/3
Y1 - 2005/3
N2 - We demonstrated previously that neonatal proximal tubules have a lower passive paracellular permeability to chloride ions and higher resistance than that of adult proximal tubules. In addition, administration of thyroid hormone to neonates, before the normal maturational increase in serum thyroid hormone levels, prematurely accelerates the developmental increase in chloride permeability to adult levels. To test the hypothesis that there is a maturational change in tight junction proteins and that thyroid hormone mediates these changes, we examined the two known tight junction proteins present in proximal tubules, occludin and claudin 2. Using immunoblot and immunohistochemistry, we demonstrated that claudin 2 has a 4-fold greater abundance in neonatal proximal tubules than in adult tubules. Occludin, however, has a 4-fold greater expression in adult tubules than in neonatal tubules. Administration of thyroid hormone to neonates did not affect claudin 2 expression, occludin expression, or the transepithelial resistance in rat proximal tubule cells in vitro. In conclusion, there are postnatal maturational changes in tight junction proteins. The factors that cause these maturational changes are unknown but unlikely to be due solely to the maturational increase in thyroid hormone.
AB - We demonstrated previously that neonatal proximal tubules have a lower passive paracellular permeability to chloride ions and higher resistance than that of adult proximal tubules. In addition, administration of thyroid hormone to neonates, before the normal maturational increase in serum thyroid hormone levels, prematurely accelerates the developmental increase in chloride permeability to adult levels. To test the hypothesis that there is a maturational change in tight junction proteins and that thyroid hormone mediates these changes, we examined the two known tight junction proteins present in proximal tubules, occludin and claudin 2. Using immunoblot and immunohistochemistry, we demonstrated that claudin 2 has a 4-fold greater abundance in neonatal proximal tubules than in adult tubules. Occludin, however, has a 4-fold greater expression in adult tubules than in neonatal tubules. Administration of thyroid hormone to neonates did not affect claudin 2 expression, occludin expression, or the transepithelial resistance in rat proximal tubule cells in vitro. In conclusion, there are postnatal maturational changes in tight junction proteins. The factors that cause these maturational changes are unknown but unlikely to be due solely to the maturational increase in thyroid hormone.
UR - http://www.scopus.com/inward/record.url?scp=14344251315&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14344251315&partnerID=8YFLogxK
U2 - 10.1203/01.PDR.0000151354.07752.9B
DO - 10.1203/01.PDR.0000151354.07752.9B
M3 - Article
C2 - 15585672
AN - SCOPUS:14344251315
VL - 57
SP - 453
EP - 457
JO - Pediatric Research
JF - Pediatric Research
SN - 0031-3998
IS - 3
ER -