Biology subjects

Jaeschke, H.

Publications and source records attributed to Jaeschke, H..

6 recordsLinked to original sources

bioRxiv2026

Differential Protection against Acetaminophen-induced Liver and Kidney Injury by N-Acetylcysteine and Fomepizole in Female Mice

Acetaminophen (APAP) overdose is the leading cause of acute liver failure and is frequently complicated by acute kidney injury (AKI), which worsens clinical outcomes. Although N-acetylcysteine (NAC) effectively attenuates APAP-induced hepatotoxicity by restoring hepatic glutathione (GSH), its efficacy against AKI remains limited, suggesting distinct mechanisms of renal injury. We investigated the role of GSH homeostasis and potential beneficial effects of NAC and Fomepizole (4-methylpyrazole) in APAP-induced liver and kidney injury using female C57BL/6J mice, which naturally lack renal CYP2E1 expression and therefore provide a unique model to examine nephrotoxicity independent of renal CYP2E1-mediated bioactivation. Female mice received APAP (300 or 600 mg/kg) with or without buthionine sulfoximine (BSO, 50 mg/kg) to inhibit GSH synthesis, NAC (500 mg/kg) to promote GSH recovery, or Fomepizole (50 mg/kg) to inhibit CYP2E1-mediated bioactivation. APAP overdose caused severe hepatotoxicity, whereas kidney injury remained minimal during the first 24 h. Although BSO markedly enhanced hepatic GSH depletion and liver injury, it did not significantly worsen renal dysfunction or tubular injury. In contrast, NAC substantially reduced liver injury and improved survival after severe APAP overdose; yet renal dysfunction progressed by 48 h, accompanied by tubular vacuolation, increased KIM-1 and osteopontin expression, and tubular cell death. Fomepizole substantially protected both organs from injury. These findings demonstrate that delayed APAP-induced AKI can develop independent of the severity of liver injury, even with effective NAC-mediated hepatoprotection. On the other hand, Fomepizole protects against AKI in female mice by a CYP2E1-independent mechanism.

pharmacology and toxicology↗

bioRxiv2026

Adenosine A2B Receptor Activation: A Novel Therapeutic Strategy for Accelerating Liver Recovery After Acetaminophen Overdose

An acetaminophen (APAP) overdose is the leading cause of drug-induced hepatotoxicity and acute liver failure (ALF) in the United States. While N-acetylcysteine (NAC), is highly effective when administered early after an overdose, its efficacy decreases with delayed administration. Since most patients present late to the clinic, there is an urgent need for novel late-acting therapeutic options to prevent progression to ALF. We previously demonstrated the benefit of delayed activation of the Adenosine A2B Receptor (A2BAR) in attenuating APAP-induced hepatotoxicity and this study focuses on its effects on liver recovery after injury. Fasted male C57BL/6J mice were treated with 300 mg/kg APAP, followed by activation of A2BAR 6 or 9 h later and sacrifice 24, 48 or 72 h post-APAP with evaluation of liver injury, the innate immune response and liver regeneration. Delayed activation of A2BAR significantly enhanced liver recovery, with accelerated repopulation of the liver by Kupffer cells, increased macrophage migration to the necrotic areas and their faster resolution. A2BAR activation also upregulated lipid metabolism-related genes in non-parenchymal cells and cell proliferation and metabolism genes in hepatocytes. Remarkably, genes such as Cidec and Plin2, crucial for lipid droplet formation, were upregulated, indicating that A2ABR activation enhances lipid metabolism which plays a key role in providing energy for liver regeneration. Overall, these findings highlight the potential of A2BAR activation not only in protecting against liver injury, but also in promoting and accelerating liver regeneration by modulating the innate immune responses and metabolic pathways.

pharmacology and toxicology↗

bioRxiv2026

Differentiating Hepatic and Renal Toxicity Reveals CYP-Independent Mechanisms of Acetaminophen-Induced Acute Kidney Injury

Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF), with acute kidney injury (AKI) contributing substantially to morbidity and mortality in those patients. To determine whether APAP-induced AKI depends on hepatic CYP2E1-mediated bioactivation, we used CYP2E1^flox/flox^ mice treated with AAV8-TBG-Cre to selectively delete hepatic CYP2E1 while preserving renal metabolism. Male and female mice received APAP (600 mg/kg) and were evaluated up to 48 hours for liver and kidney injury. Liver-specific CYP2E1 deletion reduced APAP hepatotoxicity, confirming the absence of hepatic NAPQI formation. Despite this protection, both male and female mice treated with AAV8-TBG-Cre and APAP developed progressive renal injury, with marked increases in blood urea nitrogen (BUN) and creatinine, tubular vacuolation, and strong induction of KIM-1 and osteopontin, along with apoptotic cell death at 48 hours. Notably, female mice, lacking renal CYP2E1 and displaying no detectable renal protein adducts, still progressed to AKI, demonstrating that kidney injury can occur through CYP-independent mechanisms. Given that APAP-induced AKI is a delayed injury, we further considered p-aminophenol (PAP), a deacetylation product of APAP, as a potential CYP-independent contributor. These findings support the concept that non-CYP pathways, including PAP formation, may contribute to kidney injury during the later phase of toxicity, although this pathway likely represents only one component of a multifactorial injury process. Together, these results demonstrate that APAP-induced AKI is a kidney-intrinsic process that can develop independently of both hepatic and renal CYP2E1 activity, emphasizing the need for kidney-specific therapeutic strategies for preventing APAP-induced renal injury.

pharmacology and toxicology↗

bioRxiv2026

Dysregulation of xenobiotic metabolism and mitochondrial dysfunction exacerbate acetaminophen-induced hepatotoxicity in human antigen R-deficient male mice

Acetaminophen (APAP) overdose is a leading cause of acute liver failure worldwide. The RNA-binding protein Human antigen R (HuR) is a multifunctional post-transcriptional regulator that plays a pivotal role in cellular stress responses, including those triggered by APAP toxicity. This study investigated the mechanisms by which HuR protects against APAP-induced hepatotoxicity in male mice. Hepatocyte-specific HuR-deficient (HuRHep-/-) male mice on a C57BL/6N background and wild-type (WT) littermates were treated with 200 mg/kg APAP, and liver tissues were collected at 2, 6, and 24 hours post-treatment. APAP administration increased hepatic HuR mRNA expression and induced HuR cleavage and the formation of a higher-molecular weight HuR-immunoreactive band, with the latter two correlating with injury severity. Compared with WT controls, HuRHep-/- mice exhibited markedly increased susceptibility to hepatotoxicity at both 2 and 6 hours. Metabolite profiling revealed altered APAP metabolism and reduced glutathione S-transferase (Gst) expression in HuRHep-/- livers, consistent with impaired APAP detoxification and increased APAP-protein adduct formation. Fourier-transform infrared (FTIR) spectroscopy further identified early biochemical differences between WT and HuRHep-/- livers as early as 2 hours after APAP exposure. Additionally, HuR deficiency resulted in pronounced mitochondrial structural abnormalities and dysfunction at 2 and 6 hours, accompanied by reduced expression of the mitochondrial fission and fusion proteins Drp1 and Mfn2, increased mitochondrial protein release, and enhanced hepatocyte death. Although pro-inflammatory cytokine levels were elevated in HuRHep-/- mice relative to WT controls at 24 hours, hepatocyte proliferation was similarly blunted in both genotypes, consistent with severe liver injury and delayed recovery. Collectively, these findings identify hepatocyte HuR as a critical regulator of xenobiotic metabolism and mitochondrial integrity and establish its essential role in early protection against APAP-induced hepatotoxicity in male mice.

pharmacology and toxicology↗

bioRxiv2021

Regulation of Liver Regeneration by hepatocyte O-GlcNAcylation in mice

The liver has a unique capacity to regenerate after injury in a highly orchestrated and regulated manner. Here we report that O-GlcNAcylation, an intracellular post-translational modification (PTM) regulated by two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), is a critical termination signal for liver regeneration (LR) following partial hepatectomy (PHX). We studied liver regeneration after PHX on hepatocyte specific OGT and OGA knockout mice (OGT-KO and OGA-KO), which caused a significant decrease (OGT-KO) and increase (OGA-KO) in hepatic O-GlcNAcylation, respectively. OGA-KO mice had normal regeneration, but the OGT-KO mice exhibited substantial defects in termination of liver regeneration with increased liver injury, sustained cell proliferation resulting in significant hepatomegaly, hepatic dysplasia and appearance of small nodules at 28 days after PHX. This was accompanied by a sustained increase in expression of cyclins along with significant induction in pro-inflammatory and pro-fibrotic gene expression in the OGT-KO livers. RNA-Seq studies revealed inactivation of hepatocyte nuclear 4 alpha (HNF4), the master regulator of hepatic differentiation and a known termination signal, in OGT-KO mice at 28 days after PHX, which was confirmed by both Western blot and IHC analysis. Furthermore, a significant decrease in HNF target genes was observed in OGT-KO mice, indicating a lack of hepatocyte differentiation following decreased hepatic O-GlcNAcylation. Immunoprecipitation experiments revealed HNF4 is O-GlcNAcylated in normal differentiated hepatocytes. These studies show that O-GlcNAcylation plays a critical role in the termination of LR via regulation of HNF4 in hepatocytes. Layman summaryO-GlcNAcylation is a protein modification that plays a critical role in various biological processes including cell proliferation, differentiation, and disease progression. These studies show that O-GlcNAcylation in hepatocytes is essential for proper liver regeneration. Without O-GlcNAcylation, hepatocytes keep on proliferating eventually forming liver tumors.

pathology↗

bioRxiv2019

Contrasting model mechanisms of alanine aminotransferase (ALT) release from damaged and necrotic hepatocytes as an example of general biomarker mechanisms

Interpretations of elevated blood levels of alanine aminotransferase (ALT) for drug-induced liver injury often assume that the biomarker is released passively from dying cells. However, the mechanisms driving that release have not been explored experimentally. The usefulness of ALT and related biomarkers will improve by developing mechanism-based explanations of elevated levels that can be expanded and elaborated incrementally. We provide the means to challenge the ability of closely related concretized model mechanisms to generate patterns of simulated hepatic injury and ALT release that scale (or not) to be quantitatively similar to the wet-lab validation targets. The validation targets for this work are elevated measures of plasma ALT following acetaminophen (APAP) exposure in mice. We build on a published model mechanism that helps explain the generation of characteristic spatiotemporal features of APAP hepatotoxicity within hepatic lobules. Discrete event and agent-oriented software methods are most prominent. We instantiate and leverage a small constellation of concrete model mechanisms. Their details during execution help bring into focus ways in which particular sources of uncertainty become entangled within and across several levels with cause-effect details. Monte Carlo sampling and simulations comprise a virtual experiment. Falsification of one (or more) of the model mechanisms provides new knowledge and shrinks the model mechanism constellation incrementally. We challenge the sufficiency of four potentially explanatory theories for ALT release. The first model mechanism tested failed to achieve the initial validation target, but each of the three others succeeded. We scale ALT amounts in virtual mice directly to target plasma ALT measures in individual mice. Results for one of the three model mechanisms matched all target ALT measures quantitatively. We assert that the actual mechanisms responsible for ALT measures in individual mice and the virtual causal processes occurring during model execution are strongly analogous within and among real hepatic lobular levels. Author summaryInterpretations of elevated biomarkers for drug-induced liver injury assume passive release during hepatocyte death, yet indirect evidence indicates that plasma levels can increase absent injury. Limitations on measurements make it infeasible to resolve causal linkages between drug disposition and plasma levels of biomarkers. To improve explanatory knowledge, we instantiate within virtual mice, plausible mechanism-based causal linkages between acetaminophen disposition and alanine aminotransferase (ALT) behavior that enables simulation results to meet stringent quantitative validation prerequisites. We challenge the sufficiency of four model mechanisms by scaling ALT measurements in virtual mice to corresponding plasma values. Virtual experiment results in which ALT release is a combined consequence of lobular-location-dependent hepatocyte death and drug-induced cellular damage, matches all validation targets. We assert that the actual mechanisms responsible for plasma ALT measures in individual mice and the virtual causal processes occurring during model execution are strongly analogous within and among real hepatic lobular levels.

pharmacology and toxicology↗