Inhibition of pannexin1 channels alleviates acetaminophen-induced hepatotoxicity

Abstract

Background and aims Pannexins constitute a relatively new family of transmembrane proteins that form channels linking the cytoplasmic compartment with the extracellular environment. Presence of pannexin1 in the liver has been documented previously, where it underlies inflammatory responses, such as those occurring upon ischemia-reperfusion injury. In the present study, we investigated whether pannexin1 plays a role in acute drug-induced liver toxicity. Methods Hepatic expression of pannexin1 was characterized in a mouse model of acetaminophen-induced hepatotoxicity. Subsequently, mice were overdosed with acetaminophen followed by treatment with the pannexin1 channel inhibitor 10Panx1. Sampling was performed 1, 3, 6, 24 and 48 hours after acetaminophen administration. Evaluation of the effects of pannexin1 channel inhibition was based on a number of clinically relevant read-outs, including protein adduct formation, measurement of aminotransferase activity and histopathological examination of liver tissue as well as on a series of markers of inflammation, oxidative stress and regeneration. Results Although no significant differences were found in histopathological analysis, pannexin1 channel inhibition reduced serum levels of alanine and aspartate aminotransferase. This was parallelled by a reduced amount of neutrophils recruited to the liver. Furthermore, alterations in the oxidized status were noticed with upregulation of glutathione levels upon suppression of pannexin1 channel opening. Concomitant promotion of regenerative activity was detected as judged on increased proliferating cell nuclear antigen protein quantities in 10Panx1-treated mice. Conclusions Pannexin1 channels are important actors in liver injury triggered by acetaminophen. Inhibition of pannexin1 channel opening could represent a novel approach for the treatment of drug-induced hepatotoxicity.

Enhanced Macrophage Pannexin 1 Expression and Hemichannel Activation Exacerbates Lethal Experimental Sepsis

“…Here we demonstrated that a Panx1-specific mimetic inhibitory peptide, 10Panx, reproducibly exacerbated the CLP-induced animal lethality particularly when given at relatively lower doses (10–50 mg/kg; equivalent to 8–40 µM). Because our findings seemingly contradicted with previously reported protective effects of 10Panx in other animal models of diseases (e.g., brain ischemic injury, liver toxemia injury, neuropathic pain, and epilepsy) 31,32,47,33 , we exhaustively confirmed this finding using 10Panx peptide from different sources. At a wide range of doses, 10Panx from two independent sources reproducibly worsened the outcome of lethal sepsis, confirming a deleterious effect of 10Panx in experimental sepsis.…”

“…The 10Panx is a synthetic peptide that mimics a sequence (WRQAAFVDSY) in the second extracellular loop of Panx1, and can inhibit the Panx1 hemichannel-mediated ATP release and inflammasome activation in astrocytes and macrophages 28–30 . In vivo , pharmacological blockade of Panx1 hemichannels with 10Panx peptide attenuated the progression of acetaminophen-induced hepatotoxicity 31 , neuropathic pain 32 and epilepsy 33 . Notably, the hemichannel inhibitory properties of 10Panx was mostly demonstrated at relatively higher concentrations (300–500 µM; or 370–620 µg/ml) 33–35 , and less obvious when given at lower concentrations (e.g., 100 µM; or 125 µg/ml) 36 .…”

Connexin and Pannexin (Hemi)Channels: Emerging Targets in the Treatment of Liver Disease

“…Furthermore, Panx1 ‐/‐ mice are less prone to oxidative stress and liver damage induced by acetaminophen . This is in line with the observation that pharmacological suppression of Panx1 channels reduces levels of alanine and aspartate aminotransferase, counteracts recruitment of neutrophils to the liver, and alters the hepatic oxidative status (Table ) …”

Increased Expression of Adherens Junction Components in Mouse Liver following Bile Duct Ligation

“…Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis of liver tissue was assayed as explained elsewhere [19]. The Taqman probes and primers specific for the target and reference genes (Thermo Fisher Scientific, Waltham, MA, USA) are presented in Table 1.…”

“…Immunoblot analysis of liver tissue was performed as previously described [19] with slight modifications. After electrophoresis and blotting, blocking of the nitrocellulose membranes was performed with 5% non-fatty milk in Tris-buffered saline solution containing 0.1% Tween 20.…”