Pc. Billings et al., Expression of beta ig-h3 by human bronchial smooth muscle cells localization to the extracellular matrix and nucleus, AM J RESP C, 22(3), 2000, pp. 352-359
Citations number
37
Categorie Soggetti
da verificare
Journal title
AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY
Bronchial smooth muscle cells play a central role in normal lung physiology
by controlling airway tone. In addition, airway smooth muscle hyperplasia
and hypertrophy are important factors in the pathophysiology of asthma. In
this study, expression of beta ig-h3, a recently identified component of th
e extracellular matrix (ECM), was investigated in primary human bronchial s
mooth muscle (HBSM) cells, Northern blot analysis demonstrated that treatme
nt of cultured HBSM cells with transforming growth factor-beta 1 resulted i
n a 4- to 5-fold increase in the steady-state level of beta ig-h3 messenger
RNA. Western blot analysis of secreted proteins using monospecific antibod
ies generated against peptide sequences found in the N- and C-terminal regi
ons of the protein identified several isoforms having apparent mass of 70-7
4 kD. Immunohistochemical analysis of human lung localized beta ig-h3 to th
e vascular and airway ECM, and particularly to the septal tips of alveolar
ducts and alveoli, suggesting that it may have a morphogenetic role. Analys
is of cultured HBSM cells identified beta ig-h3 in both the ECM as well as
the cytoplasm, and surprisingly also in the nucleus. These results demonstr
ate that beta ig-h3 is produced by resident lung cells, is a component of l
ung ECM, and may play an important role in lung structure and function. The
presence of this protein in nuclei suggests that it may have regulatory fu
nctions in addition to its role as a structural component of lung ECM.