Impact of intravascular hemolysis in malaria on liver dysfunction: involvement of hepatic free heme overload, NF-κB activation, and neutrophil infiltration.
We have investigated the impact of persistent intravascular hemolysis on liver dysfunction using the mouse malaria model. Intravascular hemolysis showed a positive correlation with liver damage along with the increased accumulation of free heme and reactive oxidants in liver. Hepatocytes overinduced heme oxygenase-1 (HO-1) to catabolize free heme in building up defense against this pro-oxidant milieu. However, in a condition of persistent free heme overload in malaria, the overactivity of HO-1 resulted in continuous transient generation of free iron to favor production of reactive oxidants as evident from 2',7'-dichlorofluorescein fluorescence studies. Electrophoretic mobility shift assay documented the activation of NF-κB, which in turn up-regulated intercellular adhesion molecule 1 as evident from chromatin immunoprecipitation studies. NF-κB activation also induced vascular cell adhesion molecule 1, keratinocyte chemoattractant, and macrophage inflammatory protein 2, which favored neutrophil extravasation and adhesion in liver. The infiltration of neutrophils correlated positively with the severity of hemolysis, and neutrophil depletion significantly prevented liver damage. The data further documented the elevation of serum TNFα in infected mice, and the treatment of anti-TNFα antibodies also significantly prevented neutrophil infiltration and liver injury. Deferoxamine, which chelates iron, interacts with free heme and bears antioxidant properties that prevented oxidative stress, NF-κB activation, neutrophil infiltration, hepatocyte apoptosis, and liver damage. Furthermore, the administration of N-acetylcysteine also prevented NF-κB activation, neutrophil infiltration, hepatocyte apoptosis, and liver damage. Thus, hepatic free heme accumulation, TNFα release, oxidative stress, and NF-κB activation established a link to favor neutrophil infiltration in inducing liver damage during hemolytic conditions in malaria.
Division of Infectious Diseases and Immunology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.
Sumanta
S
Dey
Samik
S
Bindu
Manish
M
Goyal
Chinmay
C
Pal
Athar
A
Alam
Mohd Shameel
MS
Iqbal
Rahul
R
Kumar
Souvik
S
Sarkar
Uday
U
Bandyopadhyay
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D017931:DNA Primers; D004195:Disease Models, Animal; D024202:Electrophoretic Mobility Shift Assay; D006418:Heme / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism; D006461:Hemolysis; D020287:In Situ Nick-End Labeling; D008099:Liver / Q000378:metabolism / Q000503:physiopathology*; D008288:Malaria / Q000469:parasitology / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism*; D020556:Neutrophil Infiltration; D018384:Oxidative Stress; D010967:Plasmodium yoelii / Q000302:isolation & purification; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000378:metabolism
D017931:DNA Primers; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D006418:Heme; D006419:Heme Oxygenase (Decyclizing)