Project description:RNAseq of liver homogenate 24h after APAP (300mg/kg) exposure followed by either MSC or HDF at 90 min. MSCs, not HDFs, ameliorate APAP-induced liver injury.
Project description:Fifty percent of all acute liver failure (ALF) cases in the United States are due to acetaminophen (APAP) overdose. Assessment of canonical features of liver injury, such as plasma alanine aminotransferase activities are poor predictors of acute liver failure (ALF), suggesting the involvement of additional mechanisms independent of hepatocyte death. Previous work demonstrated a severe overdose of APAP results in impaired regeneration, the induction of senescence by p21, and increased mortality. We hypothesized that a discrete population of p21+ hepatocytes acquired a secretory phenotype that directly impedes liver recovery after a severe APAP overdose. Leveraging in-house human APAP explant liver and publicly available singlenuclei RNAseq data, we identified a subpopulation of p21+ hepatocytes enriched in a unique secretome of factors, such as Cxcl14. Spatial transcriptomics in the mouse model of APAP overdose confirmed the presence of a p21+ hepatocyte population that directly surrounded the necrotic areas. In both male and female mice, we found a dose-dependent induction of p21 and persistent circulating levels of the p21-specific constituent, Cxcl14, in the plasma after a severe APAP overdose. In parallel experiments, we targeted either the putative senescent hepatocytes with the senolytic drugs, dasatinib and quercetin, or Cxcl14 with a neutralizing antibody. We found that targeting Cxcl14 greatly enhanced liver recovery after APAP-induced liver injury, while targeting the senescent hepatocyte had no effect. This data supports that the sustained induction of p21 in hepatocytes with persistent Cxcl14 secretion are critical mechanistic events leading to ALF in mice and human patients.
Project description:Fifty percent of all acute liver failure (ALF) cases in the United States are due to acetaminophen (APAP) overdose. Assessment of canonical features of liver injury, such as plasma alanine aminotransferase activities are poor predictors of acute liver failure (ALF), suggesting the involvement of additional mechanisms independent of hepatocyte death. Previous work demonstrated a severe overdose of APAP results in impaired regeneration, the induction of senescence by p21, and increased mortality. We hypothesized that a discrete population of p21+ hepatocytes acquired a secretory phenotype that directly impedes liver recovery after a severe APAP overdose. Leveraging in-house human APAP explant liver and publicly available singlenuclei RNAseq data, we identified a subpopulation of p21+ hepatocytes enriched in a unique secretome of factors, such as Cxcl14. Spatial transcriptomics in the mouse model of APAP overdose confirmed the presence of a p21+ hepatocyte population that directly surrounded the necrotic areas. In both male and female mice, we found a dose-dependent induction of p21 and persistent circulating levels of the p21-specific constituent, Cxcl14, in the plasma after a severe APAP overdose. In parallel experiments, we targeted either the putative senescent hepatocytes with the senolytic drugs, dasatinib and quercetin, or Cxcl14 with a neutralizing antibody. We found that targeting Cxcl14 greatly enhanced liver recovery after APAP-induced liver injury, while targeting the senescent hepatocyte had no effect. This data supports that the sustained induction of p21 in hepatocytes with persistent Cxcl14 secretion are critical mechanistic events leading to ALF in mice and human patients.
Project description:Microglial cells are the resident macrophages of the brain. Perivascular macrophages (PVM) are also myeloid resident cells that are located at the interface between blood, CSF and brain in the perivascular space. Due to their strategic location and their ability to sample CSF content, we hypothesized that PVM might play a role in CSF flow. Using different fluorescent tracers injected either into the CSF (influx) or the brain parenchyma (efflux) we assessed their spatio-temporal distribution and found that ablation (using clodronate liposomes) or dysfunction (using genetic tools) of PVM alters CSF dynamics and patterns. Using single cell RNA sequencing, we found that PBMs can be divided in two sub-populations, and that one population of PBMs could interact with vascular smooth muscle cells, which allow arterial pulsations and subsequently CSF flow. Interestingly, aging results in altered PVM phenotype, and reversing this phenotype using macrophage specific grown factors reversed some of aging-associated dysfunctions of CSF flow. In summary, our results identify a new role of PVM in CSF flow and open new avenues for therapeutical applications targeting PVM in neurodegenerative diseases such as Alzheimer’s disease.
Project description:Microglial cells are the resident macrophages of the brain. Perivascular macrophages (PVM) are also myeloid resident cells that are located at the interface between blood, CSF and brain in the perivascular space. Due to their strategic location and their ability to sample CSF content, we hypothesized that PVM might play a role in CSF flow. Using different fluorescent tracers injected either into the CSF (influx) or the brain parenchyma (efflux) we assessed their spatio-temporal distribution and found that ablation (using clodronate liposomes) or dysfunction (using genetic tools) of PVM alters CSF dynamics and patterns. Using single cell RNA sequencing, we found that PBMs can be divided in two sub-populations, and that one population of PBMs could interact with vascular smooth muscle cells, which allow arterial pulsations and subsequently CSF flow. Interestingly, aging results in altered PVM phenotype, and reversing this phenotype using macrophage specific grown factors reversed some of aging-associated dysfunctions of CSF flow. In summary, our results identify a new role of PVM in CSF flow and open new avenues for therapeutical applications targeting PVM in neurodegenerative diseases such as Alzheimer’s disease.
Project description:Microglial cells are the resident macrophages of the brain. Perivascular macrophages (PVM) are also myeloid resident cells that are located at the interface between blood, CSF and brain in the perivascular space. Due to their strategic location and their ability to sample CSF content, we hypothesized that PVM might play a role in CSF flow. Using different fluorescent tracers injected either into the CSF (influx) or the brain parenchyma (efflux) we assessed their spatio-temporal distribution and found that ablation (using clodronate liposomes) or dysfunction (using genetic tools) of PVM alters CSF dynamics and patterns. Using single cell RNA sequencing, we found that PBMs can be divided in two sub-populations, and that one population of PBMs could interact with vascular smooth muscle cells, which allow arterial pulsations and subsequently CSF flow. Interestingly, aging results in altered PVM phenotype, and reversing this phenotype using macrophage specific grown factors reversed some of aging-associated dysfunctions of CSF flow. In summary, our results identify a new role of PVM in CSF flow and open new avenues for therapeutical applications targeting PVM in neurodegenerative diseases such as Alzheimer’s disease.
Project description:Microglial cells are the resident macrophages of the brain. Perivascular macrophages (PVM) are also myeloid resident cells that are located at the interface between blood, CSF and brain in the perivascular space. Due to their strategic location and their ability to sample CSF content, we hypothesized that PVM might play a role in CSF flow. Using different fluorescent tracers injected either into the CSF (influx) or the brain parenchyma (efflux) we assessed their spatio-temporal distribution and found that ablation (using clodronate liposomes) or dysfunction (using genetic tools) of PVM alters CSF dynamics and patterns. Using single cell RNA sequencing, we found that PBMs can be divided in two sub-populations, and that one population of PBMs could interact with vascular smooth muscle cells, which allow arterial pulsations and subsequently CSF flow. Interestingly, aging results in altered PVM phenotype, and reversing this phenotype using macrophage specific grown factors reversed some of aging-associated dysfunctions of CSF flow. In summary, our results identify a new role of PVM in CSF flow and open new avenues for therapeutical applications targeting PVM in neurodegenerative diseases such as Alzheimer’s disease.
Project description:This SuperSeries is composed of the following subset Series:; GSE5593: Acetaminophen (APAP) Rat Blood Training Gene Expression Data Set; GSE5594: Acetaminophen (APAP) Rat Blood Test Gene Expression Data Set; GSE5595: Acetaminophen (APAP) Rat Liver Test Gene Expression Data Set; The Supplementary files (appended below) contain the mapping for the decoding of blinded samples. Experiment Overall Design: Refer to individual Series