Project description:The liver has a remarkable capacity for regeneration after injury. Midlobular hepatocytes have been proposed as the most plastic hepatic cell type, providing definitive evidence that zone 2 of the liver lobule acts as a reservoir for hepatocyte proliferation during homeostasis and regeneration. However, the implication of other mechanisms beyond hyperplasia that contribute to liver repair have been little explored and the collaboration of another hepatocyte subpopulation has differed among previous studies depending on the model of liver injury used. Thus, re-examination of dynamics of hepatocytes during regeneration is critical to get a better understanding of underlaying mechanisms for potential cell therapy and treatment of liver diseases. Here, using a mouse model of hepatocyte- and non-hepatocyte-specific multicolor lineage tracing, we demonstrate that hepatocytes located in the midlobular region also undergo hypertrophy besides cell division in response to chemical, physical, and viral insults. Our study shows for first time that this subpopulation also combats liver impairment after infection with coronavirus. Furthermore, we demonstrate that pericentral hepatocyte subpopulation also expands in number and size during the repair process in collaboration with midlobular hepatocytes and Galectin-9-CD44 pathway may be critical for driving these processes. Interestingly, we identified transdifferentiation and cell fusion processes during liver regeneration after severe injury that may be key to recover hepatic function.
Project description:Midlobular hepatocytes are proposed to be the most plastic hepatic cell, providing a reservoir for hepatocyte proliferation during homeostasis and regeneration. However, other mechanisms beyond hyperplasia have been little explored and the contribution of other hepatocyte subpopulations to regeneration has been controversial. Thus, re-examining hepatocyte dynamics during regeneration is critical for cell therapy and treatment of liver diseases. Using a mouse model of hepatocyte- and non-hepatocyte- multicolor lineage tracing, we demonstrate that midlobular hepatocytes also undergo hypertrophy in response to chemical, physical, and viral insults. Our study shows that this subpopulation also combats liver impairment after infection with coronavirus. Furthermore, we demonstrate that pericentral hepatocytes also expand in number and size during the repair process and Galectin-9-CD44 pathway may be critical for driving these processes. Notably, we also identified that transdifferentiation and cell fusion during regeneration after severe injury contribute to recover hepatic function.
Project description:We examined how each chemical contributed to hepatocyte revitalization by removing each component of the 5C induction cocktail individually. We then compared deach chemical contributed to hepatocyte revitalization by removing each component of the 5C induction cocktail individually
Project description:Carcinoma VCaP tumors that evolve in denervated rat prostate glands exhibited a significantly altered gene expression profile and phenotype as compared with VCaP tumors that evolve in the normal, innervated rat prostate gland. Interestingly, unilateral denervation resulted in a reduction in tumor size relative to control and the reduction was more pronounced with botox (chemical denervation) as compared with MPG excision (physical denervation). Chemical and Physical denervation yield similar gene expression profiles.
Project description:NF-κB has a crucial tumor-suppression role in chemical hepatocarcinogenesis (HCC) by preventing hepatocyte apoptosis-induced compensatory proliferation. However, NF-κB is typically activated in chemical HCC animal models and in ~40% HCC patients, in which its role in tumor progression is largely not known. Here we report that transcription factor Miz1 limits tumor-promoting function of NF-κB independently of its transcriptional activity in chemical HCC. In a murine model, hepatocyte-specific deletion of Miz1 exacerbates HCC progression. Miz1 loss results in a unique sub-group of hepatocytes with upregulated NF-κB activity and pro-inflammatory cytokine production, skewing infiltrating macrophages toward M1-like pro-inflammatory phenotype. Mechanistically, Miz1 sequestrates and prevents IKK-phosphorylation of Metadherin (MTDH), thereby inhibiting NF-κB nuclear translocation and transcription activity. In HCC patient specimens, Miz1 expression is inversely correlated with phosphorylation of RelA and MTDH, and poor prognosis. Thus, Miz1 preventing hepatocytes from promoting infiltrating macrophage M1-like phenotype and inflammation in chemical HCC progression.