Molecular mechanisms of liver ischemia reperfusion injury: Insights from transgenic knockout models

Table 5 Knockouts of downstream mediators and models of liver ischemia reperfusion injury

Ref.	Knockout model	IR protocol	Outcome measure	Agent	Adaptive responses	Injurious responses
Theruvath et al[14,15]	JNK (-/-)	70% I 1 h/R 4, 8 h	Histology; serum ALT; IVM (dyes to probe mitochondrial function and cell death); survival 14 d			JNK2 activation leads to mitochondrial depolarization and increased necrosis only
Theruvath et al[14,15]	JNK (-/-)	WT or KO donor; 30 h, 4  °C, UWS preservation; WT recipient	Histology 8 h posttransplant; serum ALT, TUNEl and caspase-3 assay; IVM; IH; lipid peroxidation			JNK2 activation leads to caspase-3 activation, mitochondrial depolarisation and release of cytochrome c, lipid peroxidation which all translate into reduced survival posttransplant
Beraza et al[72]	Conditional hepatocyte specific NEMO knockout	70% I 1 h (caudate lobe resected)/R 3, 6 h	TUNEL and caspase-3 assay; WB; IH; Southern blotting; EMSA (NFκβ)		NFκβ activity reduces necrosis and apoptosis, inhibits TNF-α, JNK and iNOS
Okaya et al[35]	PPARα (-/-)	70%I 90 min/R 4, 8 h	Serum ALT; TNF-α; MIP-2; MPO; liver NO2/NO3; WB; EMSA (AP-1, NFκβ)	WY14643 iv (PPARα agonist)	PPARα protective in IRI	PPARα independent release of TNF-α and MIP-2 and increased NO2/NO3 associated with IRI
Shen et al[78]	STAT4 (-/-); STAT6 (-/-); nu/nu	70%I 90 min/R 6 h	Serum ALT; histology; MPO; WB; PCR	Adoptive transfer of CD4+ T cells from WT or other KO to nu/nu; SnPP ip	HO-1 expressed at very low levels after 6 h in this model, but protective in IRI	CD4+T cell activation involving T cell STAT4 activation, but not STAT6 associated with increased IRI
Khandoga et al[61]	PARP (-/-)	Left lobe I 90 min/R 30 min	Serum ALT; IVM; IH; PCR			PARP activation in IRI upregulates E-selectin, ICAM1 and VCAM1, associated with increased platelet and leucocyte endothelial interaction and reduced sinusoidal perfusion
Kato et al[82]	P50 NFκβ (-/-)	70% I 90 min/R 1, 8 h	Serum ALT; histology; MPO WB; EMSA (p50 and p65 subunits of NFκβ)			No effect of p50 subunit deletion, but increased p50/p65 heterodimer in WT and some p65 in KO, so there may be some functional redundancy of NFκβ subunits
Kato et al[83]	STAT4 (-/-)	70% I 90 min/R 30 min, 1, 2, 4, 8 h	Serum ALT; histology; MPO; WB	Anti IL12 Ab		IL12 expression associated with IRI. STAT4 not activated in IRI in this model
Kato et al[70]	STAT6 (-/-)	70% I 90 min/R 1, 4, 8 h	Serum ALT, TNF-α; MPO; PCR; EMSA (NFκβ)	IL4 or IL13 iv		STAT6 is not activated in IRI in this model, although STAT6 activation by iv IL4 or IL13 is protective. IRI is associated with increased NFκβ DNA binding

KO: Transgenic knockout; WT: Wild type (normal animals); IH: Immunohistochemistry; WB: Western blotting; MPO: Myeloperoxidase assay; PCR: Polymerase chain reaction; EMSA: Electrophoretic mobility shift assay; ALT: Alanine transaminase; I: Ischemia; R: Reperfusion; IR: Ischemia reperfusion; IRI: Ischemia reperfusion injury; IVM: Intravital microscopy; IFN: Interferon; Ab: Antibody; TNF: Tumour necrosis factor; TNFR1: Tumour necrosis factor receptor (subtype 1); TUNEL: Terminal deoxynucleotidyl transferase dUTP nick end labeling (assay for cell death); IL: Interleukin; NF: Nuclear factor; STAT: Signal Transducer and Activator of Transcription; JNK: A survival kinase; PARP: Poly (ADP-ribose) polymerase.