TY - JOUR
T1 - Triiodothyronine alters the cornification of cultured human keratinocytes
AU - Isseroff, Roslyn Rivkah
AU - Chun, K. T.
AU - Rosenberg, R. M.
PY - 1989
Y1 - 1989
N2 - Scaly skin occurs in 80-90% of patients who are hypothyroid, the pathogenesis of which is unknown. Since thyroid hormone (T3) affects growth and differentiation in other organs, we examined the effects of its absence on keratinocytes in vitro. Human neonatal foreskin keratinocytes were cultivated and second passage cells were switched to T3-depleted (-T3) medium at 50% confluence. Cells maintained in the -T3 medium demonstrated increased (1.5 fold) levels of the cross-linking enzyme transglutaminase and increased (1.5 fold) formation of cornified envelopes, when compared to keratinocytes maintained in medium containing physiologic levels (2 x 10-9 M) of T3. Additionally, in the -T3 cultures, the level of the protease plasminogen activator (PA), an enzyme implicated in the process of shedding of cornified cells, was decreased 70-80% of that measured in +T3 media. Absence of T3 from keratinocyte culture-medium increased both the level of the enzyme responsible for cross-linking cornified envelope precursors and the rate of envelope formation in cultured cells. The decreased levels of PA observed in the -T3 cultures could result in decreased shedding of cornified cells. These alterations in the process of keratinocyte differentiation may explain the clinically observed scaliness associated with hypothyroidism in humans. The molecular mechanism by which T3 alters keratinocyte cornification is not yet known.
AB - Scaly skin occurs in 80-90% of patients who are hypothyroid, the pathogenesis of which is unknown. Since thyroid hormone (T3) affects growth and differentiation in other organs, we examined the effects of its absence on keratinocytes in vitro. Human neonatal foreskin keratinocytes were cultivated and second passage cells were switched to T3-depleted (-T3) medium at 50% confluence. Cells maintained in the -T3 medium demonstrated increased (1.5 fold) levels of the cross-linking enzyme transglutaminase and increased (1.5 fold) formation of cornified envelopes, when compared to keratinocytes maintained in medium containing physiologic levels (2 x 10-9 M) of T3. Additionally, in the -T3 cultures, the level of the protease plasminogen activator (PA), an enzyme implicated in the process of shedding of cornified cells, was decreased 70-80% of that measured in +T3 media. Absence of T3 from keratinocyte culture-medium increased both the level of the enzyme responsible for cross-linking cornified envelope precursors and the rate of envelope formation in cultured cells. The decreased levels of PA observed in the -T3 cultures could result in decreased shedding of cornified cells. These alterations in the process of keratinocyte differentiation may explain the clinically observed scaliness associated with hypothyroidism in humans. The molecular mechanism by which T3 alters keratinocyte cornification is not yet known.
UR - http://www.scopus.com/inward/record.url?scp=0024601745&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024601745&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2133.1989.tb01323.x
DO - 10.1111/j.1365-2133.1989.tb01323.x
M3 - Article
C2 - 2471545
AN - SCOPUS:0024601745
VL - 120
SP - 503
EP - 510
JO - British Journal of Dermatology
JF - British Journal of Dermatology
SN - 0007-0963
IS - 4
ER -