Nuclear factor-kappaB mediates Kupffer cell apoptosis through transcriptional activation of Fas/FasL.
BACKGROUND
Nuclear factor (NF)-kappaB is a key transcriptional factor for cell survival, inflammation, and stress response. We demonstrated that Kupffer cell-derived FasL plays a central role in pancreatitis-induced hepatocyte injury. The aim of this study was to determine the role of NF-kappaB in regulating death ligand/receptor pathway in Kupffer cells during conditions that mimic acute pancreatitis.


METHODS
Tissue cultures of rat Kupffer cells were treated with elastase (1 U/L) to mimic pancreatitis before and after infection with AdIkappaB to block activation of NF-kappaB. Tumor necrosis factor (enzyme-linked immunoassay), Fas/FasL, and caspase-3 (Western), tumor necrosis factor and Fas/FasL mRNA (reverse-transcription polymerase chain reaction), and NF-kappaB DNA binding (electrophoretic mobility shift assay) were determined. Apoptosis was measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) and DNA fragmentation. Gels were quantified by densitometry. Data (n=3) are mean+/-SEM; student's t test was used for statistical analysis.


RESULTS
AdIkappaB infection up-regulated mutated IkappaBalpha that maintained its binding properties to NF-kappaB. Promoter-reporter assay demonstrated that FasL gene promoter was regulated by NF-kappaB. Infection with AdIkappaB attenuated the elastase-induced up-regulation of Fas/FasL (all P<0.01 versus elastase) and NF-kappaB DNA binding but did not affect elastase-induced up-regulation of TNF. AdIkappaB attenuated elastase-induced cleavage of caspase-3, DNA fragmentation and TUNEL staining (all P<0.01 versus elastase).


CONCLUSIONS
Inhibition of NF-kappaB DNA binding down-regulates Fas/FasL and attenuates elastase-induced apoptosis; however, it has no effect on TNF production, suggesting that regulation of Fas/FasL and TNF may occur via different pathways. The ability of Kupffer cells to autoregulate their stress response by up-regulating their death ligand/receptor and apoptosis warrants further investigation.
Peng
Yanhua
Y
Department of Surgery, James A. Haley Veterans Affairs Medical Center, and University of South Florida Health Sciences Center, Tampa, Florida 33601, USA.
Gallagher
Scott F
SF
Haines
Krista
K
Baksh
Kathryn
K
Murr
Michel M
MM
D000208:Acute Disease; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002461:Cell Line, Transformed; D003587:Cytomegalovirus / Q000235:genetics; D053222:Fas Ligand Protein; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D007728:Kupffer Cells / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D016296:Mutagenesis; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000494:pharmacology; D010195:Pancreatitis / Q000378:metabolism / Q000503:physiopathology; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015533:Transcriptional Activation / Q000187:drug effects / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D048069:Tumor Necrosis Factors / Q000235:genetics*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D019014:fas Receptor / Q000235:genetics*
D053222:Fas Ligand Protein; C505662:Faslg protein, rat; D020672:I-kappa B Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; D014409:Tumor Necrosis Factor-alpha; D048069:Tumor Necrosis Factors; D019014:fas Receptor; D000072000:NF-KappaB Inhibitor alpha; D010196:Pancreatic Elastase; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases