Distamycin A inhibits HMGA1-binding to the P-selectin promoter and attenuates lung and liver inflammation during murine endotoxemia.
BACKGROUND
The architectural transcription factor High Mobility Group-A1 (HMGA1) binds to the minor groove of AT-rich DNA and forms transcription factor complexes ("enhanceosomes") that upregulate expression of select genes within the inflammatory cascade during critical illness syndromes such as acute lung injury (ALI). AT-rich regions of DNA surround transcription factor binding sites in genes critical for the inflammatory response. Minor groove binding drugs (MGBs), such as Distamycin A (Dist A), interfere with AT-rich region DNA binding in a sequence and conformation-specific manner, and HMGA1 is one of the few transcription factors whose binding is inhibited by MGBs.


OBJECTIVE
To determine whether MGBs exert beneficial effects during endotoxemia through attenuating tissue inflammation via interfering with HMGA1-DNA binding and modulating expression of adhesion molecules.


RESULTS
Administration of Dist A significantly decreased lung and liver inflammation during murine endotoxemia. In intravital microscopy studies, Dist A attenuated neutrophil-endothelial interactions in vivo following an inflammatory stimulus. Endotoxin induction of P-selectin expression in lung and liver tissue and promoter activity in endothelial cells was significantly reduced by Dist A, while E-selectin induction was not significantly affected. Moreover, Dist A disrupted formation of an inducible complex containing NF-kappaB that binds an AT-rich region of the P-selectin promoter. Transfection studies demonstrated a critical role for HMGA1 in facilitating cytokine and NF-kappaB induction of P-selectin promoter activity, and Dist A inhibited binding of HMGA1 to this AT-rich region of the P-selectin promoter in vivo.


CONCLUSIONS
We describe a novel targeted approach in modulating lung and liver inflammation in vivo during murine endotoxemia through decreasing binding of HMGA1 to a distinct AT-rich region of the P-selectin promoter. These studies highlight the ability of MGBs to function as molecular tools for dissecting transcriptional mechanisms in vivo and suggest alternative treatment approaches for critical illness.
Baron
Rebecca M
RM
Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America. rbaron@partners.org
Lopez-Guzman
Silvia
S
Riascos
Dario F
DF
Macias
Alvaro A
AA
Layne
Matthew D
MD
Cheng
Guiying
G
Harris
Cailin
C
Chung
Su Wol
SW
Reeves
Raymond
R
von Andrian
Ulrich H
UH
Perrella
Mark A
MA
D020856:AT Rich Sequence; D000818:Animals; D002417:Cattle; D002450:Cell Communication / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D004214:Distamycins / Q000494:pharmacology / Q000627:therapeutic use*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019446:Endotoxemia / Q000150:complications / Q000188:drug therapy* / Q000473:pathology / Q000517:prevention & control; D004731:Endotoxins; D025741:HMGA1a Protein / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000150:complications / Q000378:metabolism / Q000473:pathology; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019007:P-Selectin / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects
D016207:Cytokines; D004214:Distamycins; D004731:Endotoxins; D016328:NF-kappa B; D019007:P-Selectin; D025741:HMGA1a Protein; C030000:stallimycin