Lipopolysaccharide up-regulates heat shock protein expression in rat lung pericytes.
BACKGROUND
Heat shock proteins (HSP) function as molecular chaperones, participating in protein folding and maturation throughout the cell. Serum HSPs may correlate with acute lung injury. Pericytes are perivascular cells located abluminally from endothelial cells, and play a regulatory role in capillary leak. It is our hypothesis that pericytes express HSP 60 and HSP 70, and these HSPs are up-regulated in response to lipopolysaccharide (LPS).


METHODS
Rat microvascular lung pericytes were isolated and cultured. Cells from passages three to five were used and treated with LPS (control, 10 ng/mL, and 100 ng/mL) for either 4 or 18 h. Immunoblotting and real-time PCR were used to analyze the presence and quantity of HSP 60 and HSP 70.


RESULTS
Immunoblotting revealed the presence of HSP 60 and HSP 70 in control pericytes. After 4 h of treatment with LPS (10 ng/mL and 100 ng/mL), no increase in protein expression of HSP 60 or HSP 70 was seen. However, after 18 h an increase in protein expression of HSP 60 and HSP 70 was seen. Real-time PCR demonstrated the presence of HSP 60 mRNA and HSP 70 mRNA in control pericytes. An increase in mRNA was seen after 18 h of LPS treatment, but not after 4 h.


CONCLUSIONS
This study provides the first in vitro evidence that rat lung pericytes express HSP 60 and HSP 70. HSP 60 and HSP 70 are up-regulated after 18 h of LPS exposure. Pericyte heat shock protein expression may contribute to the lung's response seen in sepsis.
Edelman
David A
DA
Wayne State University, Detroit Medical Center, Detroit, Michigan, USA.
Jiang
Yang
Y
Tyburski
James G
JG
Wilson
Robert F
RF
Steffes
Christopher P
CP
D000818:Animals; D002478:Cells, Cultured; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000098:blood supply* / Q000166:cytology; D020286:Pericytes / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects*
D018834:Chaperonin 60; D018840:HSP70 Heat-Shock Proteins; D008070:Lipopolysaccharides; D012333:RNA, Messenger