Transplanted hepatocytes rescue mice in acetaminophen‐induced acute liver failure through paracrine signals for hepatic ATM and STAT3 pathways

Abstract

Acute liver failure constitutes a devastating condition that needs novel cell and molecular therapies. To elicit synergisms in cell types of therapeutic interest, we studied hepatocytes and liver sinusoidal endothelial in mice with acetaminophen-induced acute liver failure. The context of regenerative signals was examined by transplants in peritoneal cavity because it possesses considerable capacity and allows soluble signals to enter the systemic circulation. Whereas transplanted hepatocytes and liver sinusoidal endothelial cells engrafted in peritoneal cavity, only the former could rescue mice in liver failure by improving injury outcomes, activating hepatic DNA damage repair, and inducing liver regeneration. The cytokines secreted by donor hepatocytes or liver sinusoidal endothelial cells differed and in hepatocytes from mice undergoing acetaminophen toxicity major cytokines were even rendered deficient (eg, G-CSF, VEGF, and others). Significantly, recapitulating hepatotoxicity-related DNA damage response in cultured cells identified impairments in ATM and JAK/STAT3 intersections since replacing cytokines produced less from injured hepatocytes restored these pathways to avoid acetaminophen hepatotoxicity. Similarly, hepatocyte transplantation in acute liver failure restored ATM and JAK/STAT3 pathways to advance DNA damage/repair and liver regeneration. The unexpected identification of novel hepatic G-CSF receptor expression following injury allowed paradigmatic studies of G-CSF supplementation to confirm the centrality of this paracrine ATM and STAT3 intersection. Remarkably, DNA damage/repair and hepatic regeneration directed by G-CSF concerned rebalancing of regulatory gene networks overseeing inflammation, metabolism, and cell viability. We conclude that healthy donor hepatocytes offer 2 of 16 | VISWANATHAN eT Al.

The Dual Role of Innate Immune Response in Acetaminophen-Induced Liver Injury

“…For example, TNF-α can be secreted by KCs, macrophages, and DC cells; the mechanism of KCs in AILI is oppositional [ 52 , 54 ]. Second, cytokine secretion is also regulated by cellular signaling pathways, such as JNK [ 116 ], STAT3 [ 117 ], MAPK [ 118 ], and TLR4 [ 50 ] signaling pathways. Our previous study suggested that the notch pathway reduces macrophage and neutrophil infiltration to alleviate AILI, reducing mRNA expression with TNF-α, L-1β, and IL-6 [ 119 ].…”

The immunological mechanisms and therapeutic potential in drug-induced liver injury: lessons learned from acetaminophen hepatotoxicity

“…Evidence suggests that CSF is also involved in AILI. Gao et al found a reduction of granulocyte-CSF (G-CSF) and granulocyte–macrophage-CSF (GM-CSF) in AILI [ 208 ], while Viswanathan et al found a higher abundance of GM-CSF and G-CSF expression in conditioned medium of AILI-derived hepatocytes [ 186 ]. In the plasma of an 18-year-old patient with APAP-induced ALF, an increased expression of IL-6, IL-8 and G-CSF is found, and elevated G-CSF levels may contribute to hepatic neutrophil vacuolization [ 240 ].…”

“…Excessive APAP-treated human hepatocytes and PRHs express G-CSF receptor (G-CSFR) and GM-CSF receptor (GM-CSFR) involved in JAK/STAT3 signaling [ 243 ]. Livers from APAP hepatotoxic mice have the defective expression of G-CSF and vascular endothelial growth factor (VEGF) [ 186 ], and replacement of the expression of these factors or receptors by transplantation of healthy hepatocytes would further improve liver homeostasis and promote liver regeneration. Mice lacking G-CSF weaken the protective role of neutrophils in liver repair during APAP challenge [ 86 ].…”

“…Studies of excess APAP-stimulated mouse and human primary hepatocytes have found very rapid, intense, and sustained activation of EGF receptor (EGFR) in the early stage of injury, which are possibly triggered by GSH depletion, after which levels of a series of toxicity markers begin to rise, and activation of EGFR signaling may contribute to late liver regeneration [ 247 ]. Viswanathan et al detected chemokines in a conditioned medium of AILI-derived hepatocytes revealing the higher abundance of VEGF-D (11-fold), VEGF (1.7-fold), its receptors VEGF-R3 and VEGF-R2 (sixfold), and lower expression of VEGF-R1 (0.7-fold) and HGF-R (0.6-fold), and VEGF may activate the STAT3 and ATM pathways[ 186 ]. Bone-Larson et al demonstrated that CXCL10 protects MIP-2 receptors against APAP hepatotoxicity by inducing HGF production [ 235 ].…”

A phase II, multicenter, open-label, randomized trial of pegfilgrastim for patients with alcohol-associated hepatitis

“…Receptors for GCSF have been identified on hepatocytes, raising the possibility of direct activation of hepatocyte regeneration. 13 Finally, it is postulated that GCSF promotes a neutrophil phenotype that responds more effectively to bacterial translocation and infection. 14 …”