Project description:Several studies indicate that adult stem cells may improve the recovery from acute tissue injury. It has been suggested that they may contribute to tissue regeneration by the release of paracrine factors promoting proliferation of tissue resident cells. However, the factors involved remain unknown. In the present study we found that microvesicles (MV) derived from human liver stem cells (HLSC) were able to stimulate in vitro proliferation and apoptosis resistance of human and rat hepatocytes. These effects required internalization of MV in the hepatocytes by an alpha4 integrin-dependent mechanism. However, when treated with RNase, MV despites their internalization were unable to induce hepatocyte proliferation and apoptosis resistance, suggesting an RNA dependent effect. Microarray analysis and quantitative RT-PCR demonstrated that MV were shuttling a specific subset of cellular mRNA, such as mRNA associated in the control of transcription, translation, proliferation and apoptosis. When administered in vivo, MV were found to accelerate the morphological and functional recovery of liver in a model of 70% hepatectomy in rats by inducing an hepatocytes proliferation that was abolished by RNase treatment. Using human AGO2 gene, which is shuttled by MV, as a reporter gene, we found the expression of human AGO2 mRNA and protein in the liver of hepatectomized rats treated with MV. This suggest a translation of the MV shuttled mRNA within hepatocytes of treated rats. Conclusion: these results suggest that MV derived from HLSC may activate a proliferative program in remnant hepatocytes after hepatectomy by a horizontal transfer of specific mRNA subsets.
Project description:Gene expression profiles of sandwich-cutlured primary rat hepatocytes exposed to 5 mM and 10 mM acetaminophen were used in a parallelogram approach in order to compare gene expression responses between rat and human using in vitro cellular models, heaptocytes, and between rat in vitro and in vivo Experiment Overall Design: Samples were retrieved from acetaminophen treated rat hepatocyte cultures from 3 rats (3 biological replicates). Rat hepatocytes from each replicate were cultured in two culture conditions, each treated with 0, 5, and 10 mM acetaminophen for 24 h. This resulted in (3 rats x 2 culture conditions x 3 doses) 18 dual channel arrays on which control (0 mM acetaminophen) and reference samples (0, 5, and 10 mM acetaminophen) were hybridized
Project description:Wild-type and AHR-KO rats harboring a 29-bp deletion mutation in exon 2 of the AHR gene were used in this study. Wild-type and AHR-KO rats were generated from heterozygous breeding stocks generated on a Sprague-Dawley outbred background and maintained at the Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina Persistent activation of the aryl hydrocarbon receptor (AHR) is believed to play a key role in the mode-of-action for TCDD induced rat liver tumorigenesis. It has been hypothesized that the cellular responses of hepatocytes to AHR activation may differ across regions of the liver lobule and that zone-specific effects of AHR agonists may play a role in the pathogenesis of rat liver tumorigenesis. Dose-dependent changes in gene expression were observed in both populations of hepatocytes collected from WT rats which were consistent with activation of AHR signaling. No significant or dose-dependent changes in gene expression were observed in samples from AHR-KO rats. In addition, evidence of inflammatory signaling pathway activation was observed only in centrilobular hepatocytes. Evidence of cell adhesion pathway enrichment was observed only in periportial hepatocytes. Benchmark dose analysis demonstrated that dose-dependent changes in gene expression occurred at lower doses in centrilobular as compared to periportal hepatocytes. These results indicate zone-specific differences in the sensitivity and response of hepatocytes to persistent AHR activation.
Project description:We determined the microRNA expression profiles of the hepatocytes and liver sinusoidal endothelial cells (LSECs) isolated from nontreated rats.
Project description:Wild-type and AHR-KO rats harboring a 29-bp deletion mutation in exon 2 of the AHR gene were used in this study. Wild-type and AHR-KO rats were generated from heterozygous breeding stocks generated on a Sprague-Dawley outbred background and maintained at the Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina Persistent activation of the aryl hydrocarbon receptor (AHR) is believed to play a key role in the mode-of-action for TCDD induced rat liver tumorigenesis. It has been hypothesized that the cellular responses of hepatocytes to AHR activation may differ across regions of the liver lobule and that zone-specific effects of AHR agonists may play a role in the pathogenesis of rat liver tumorigenesis. Dose-dependent changes in gene expression were observed in both populations of hepatocytes collected from WT rats which were consistent with activation of AHR signaling. No significant or dose-dependent changes in gene expression were observed in samples from AHR-KO rats. In addition, evidence of inflammatory signaling pathway activation was observed only in centrilobular hepatocytes. Evidence of cell adhesion pathway enrichment was observed only in periportial hepatocytes. Benchmark dose analysis demonstrated that dose-dependent changes in gene expression occurred at lower doses in centrilobular as compared to periportal hepatocytes. These results indicate zone-specific differences in the sensitivity and response of hepatocytes to persistent AHR activation. AHR-KO and WT rats (n = 10 rats/dose/genotype) were dosed by oral gavage (4-5 doses / week, 19 total doses) with varying concentrations of TCDD in corn oil (0, 3, 22, 100, 300, 1000 ng/kg/day). Cryopreserved liver slices collected at necropsy were thawed, cryosectioned (12 µm thickness), fixed with ethanol and âquick-stainedâ with hematoxylin. Centrilobular and periportal hepatocytes were collected using laser capture microdissection. Total RNA was extracted, amplified and labeled using low-yield techniques and global transcriptomic profiles were obtained using Affymetrix Gene-Titan peg arrays.
Project description:Hepatocytes isolated from DILI patient's liver (#2064) were cultured for a long term using irrMEF and EMUKK-05, and comprehensive gene expression was compared between Puromycin-treated and non-treated groups. In addition, comprehensive gene expression analysis of human mature hepatocytes, primary cultured cells, and ips cell-derived hepatocyte-like cells were performed as controls. Two-condition experiment, Proliferating hepatocytes (ProilHH) vs. puromycin-treated ProliHH. Primary human hepatocytes (PHH) and isolated humen mature hepatocytes (MH) and human iPSC-derived hepatocyte-like cells (HLC) as controls.
Project description:A toxicogenomics approach was used to qualitatively and quantitatively compare gene expression changes in rat primary hepatocytes exposed to 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF) or 2,3,7,8-tetrachlorodibenzofuran (TCDF). Hepatocytes from five individual rats were exposed for 24 hours to 11 concentrations of each chemical ranging from 0.00001 nM to 100 nM and a vehicle control. 115 microarrays representing primary hepatocytes from 5 rats, each exposed to 11 doses of each chemical (PeCDF and TCDF) and vehicle controls. Arrays were completed with a one-color design.
Project description:Several studies indicate that adult stem cells may improve the recovery from acute tissue injury. It has been suggested that they may contribute to tissue regeneration by the release of paracrine factors promoting proliferation of tissue resident cells. However, the factors involved remain unknown. In the present study we found that microvesicles (MV) derived from human liver stem cells (HLSC) were able to stimulate in vitro proliferation and apoptosis resistance of human and rat hepatocytes. These effects required internalization of MV in the hepatocytes by an alpha4 integrin-dependent mechanism. However, when treated with RNase, MV despites their internalization were unable to induce hepatocyte proliferation and apoptosis resistance, suggesting an RNA dependent effect. Microarray analysis and quantitative RT-PCR demonstrated that MV were shuttling a specific subset of cellular mRNA, such as mRNA associated in the control of transcription, translation, proliferation and apoptosis. When administered in vivo, MV were found to accelerate the morphological and functional recovery of liver in a model of 70% hepatectomy in rats by inducing an hepatocytes proliferation that was abolished by RNase treatment. Using human AGO2 gene, which is shuttled by MV, as a reporter gene, we found the expression of human AGO2 mRNA and protein in the liver of hepatectomized rats treated with MV. This suggest a translation of the MV shuttled mRNA within hepatocytes of treated rats. Conclusion: these results suggest that MV derived from HLSC may activate a proliferative program in remnant hepatocytes after hepatectomy by a horizontal transfer of specific mRNA subsets. MV contained mRNA was submitted to microarray analysis not to define the amount of mRNA but only to define which transcripts were present. Total RNA was prepared from two independent preparation of vesicles. 250, 500 and 1000 ngs from each preparation were transformed in biotin-labeled cRNA. A simple statistical linear model was used to identify transcript signals linearly correlated to the increment of total RNA concentration used to prepare cRNA.