Hepatocyte Transplantation Rebalances Cytokines for Hepatic Regeneration in Rats with Ataxia Telangiectasia Mutated Pathway-Related Acute Liver Failure.

Inadequate DNA damage response related to ataxia telangiectasia mutated gene restricts hepatic regeneration in acute liver failure. Resolving mechanistic gaps in liver damage and repair requires additional animal models that are unconstrained by ultrarapid and unpredictable mortalities or substantial divergences from human pathology. This study used Fischer 344 rats primed with the antitubercular drug, rifampicin, plus phenobarbitone, and monocrotaline, a DNA adduct-forming alkaloid.

Transcriptional profiling reveals ataxia telangiectasia mutated pathways regulate joint copper and arsenic toxicity for hepatic metalloplasia and anti-cancer therapies.

Aims: Exposures to toxic metals, including arsenic (As), pose health risks but joint effects of physiologically needed metals, e.g., copper (Cu), are ill-defined for regulated metal-dependent cell proliferation (or metalloplasia).

Caffeine disrupts ataxia telangiectasia mutated gene-related pathways and exacerbates acetaminophen toxicity in human fetal immortalized hepatocytes.

Preterm infants are at greater risk for adverse drug effects due to hepatic immaturity. Multiple interventions during intensive care increases potential for drug interactions. In this setting, high-dose caffeine used for apnea in premature infants may increase acetaminophen toxicity by inhibiting ataxia telangiectasia mutated (ATM) gene activity during DNA damage response.

Transplanted hepatocytes rescue mice in acetaminophen-induced acute liver failure through paracrine signals for hepatic ATM and STAT3 pathways.

Acute liver failure constitutes a devastating condition that needs novel cell and molecular therapies. To elicit synergisms in cell types of therapeutic interest, we studied hepatocytes and liver sinusoidal endothelial in mice with acetaminophen-induced acute liver failure. The context of regenerative signals was examined by transplants in peritoneal cavity because it possesses considerable capacity and allows soluble signals to enter the systemic circulation.

Tumor Necrosis Factor Directs Allograft-Related Innate Responses and Its Neutralization Improves Hepatocyte Engraftment in Rats.

The innate immune system plays a critical role in allograft rejection. Alloresponses involve numerous cytokines, chemokines, and receptors that cause tissue injury during rejection. To dissect these inflammatory mechanisms, we developed cell transplantation models in dipeptidylpeptidase-deficient F344 rats using mycophenolate mofetil and tacrolimus for partial lymphocyte-directed immunosuppression.

Ataxia telangiectasia mutated pathway disruption affects hepatic DNA and tissue damage in nonalcoholic fatty liver disease.

To overcome the rising burdens of nonalcoholic fatty liver disease, mechanistic linkages in mitochondrial dysfunction, inflammation and hepatic injury are critical. As ataxia telangiectasia mutated (ATM) gene oversees DNA integrity and mitochondrial homeostasis, we analyzed mRNAs and total proteins or phosphoproteins related to ATM gene by arrays in subjects with healthy liver, fatty liver or nonalcoholic steatohepatitis. Functional genomics approaches were used to query DNA damage or cell growth events.

Cellular cytokine receptor signaling and ATM pathway intersections affect hepatic DNA repair.

Pathways involving ataxia telangiectasia mutated (ATM) gene and its downstream partners and effectors are critical for the DNA damage response. Cell survival, proliferation and tissue homeostasis are dependent upon preservation of DNA integrity but additional intracellular mechanisms contribute in these processes. As receptor-mediated signaling with beneficial intersections in ATM pathways could have therapeutic significance, we interrogated such intersections with assays using HuH-7 cells (hepatocytes).

Decellularized bovine placentome for portacavally-interposed heterotopic liver transplantation in rats.

Scaffolds from healthy placentae offer advantages for tissue engineering with undamaged matrix, associated cytoprotective molecules, and embedded vessels for revascularization. As size disparities in human placenta and small recipients hamper preclinical studies, we studied alternative of bovine placentomes in smaller size ranges. Multiple cow placentomes were decellularized and anatomical integrity was analyzed.

Genes and Pathways Promoting Long-Term Liver Repopulation by hYAP-ERT2 Transduced Hepatocytes and Treatment of Jaundice in Gunn Rats.

Hepatocyte transplantation is an attractive alternative to liver transplantation. Thus far, however, extensive liver repopulation by adult hepatocytes has required ongoing genetic, physical, or chemical injury to host liver. We hypothesized that providing a regulated proliferative and/or survival advantage to transplanted hepatocytes should enable repopulation in a normal liver microenvironment.

Efficient Reconstitution of Hepatic Microvasculature by Endothelin Receptor Antagonism in Liver Sinusoidal Endothelial Cells.

Reconstitution of healthy endothelial cells in vascular beds offers opportunities for mechanisms in tissue homeostasis, organ regeneration, and correction of deficient functions. Liver sinusoidal endothelial cells express unique functions, and their transplantation is relevant for disease models and for cell therapy. As molecular targets for improving transplanted cell engraftment and proliferation will be highly significant, this study determined whether ET receptor antagonism by the drug bosentan could overcome cell losses due to cell transplantation-induced cytotoxicity.

In Mice Modeling Wilson's Disease Liver Repopulation With Bone Marrow-Derived Myofibroblasts or Inflammatory Cells and Not Hepatocytes Is Deleterious.

In Wilson's disease, mutations impair copper excretion with liver or brain damage. Healthy transplanted hepatocytes repopulate the liver, excrete copper, and reverse hepatic damage in animal models of Wilson's disease. In mice with tyrosinemia and α-1 antitrypsin mutant mice, liver disease is resolved by expansions of healthy hepatocytes derived from transplanted healthy bone marrow stem cells.

Replicative stress and alterations in cell cycle checkpoint controls following acetaminophen hepatotoxicity restrict liver regeneration.

Objectives: Acetaminophen hepatotoxicity is a leading cause of hepatic failure with impairments in liver regeneration producing significant mortality. Multiple intracellular events, including oxidative stress, mitochondrial damage, inflammation, etc., signify acetaminophen toxicity, although how these may alter cell cycle controls has been unknown and was studied for its significance in liver regeneration.

Decellularized human placenta supports hepatic tissue and allows rescue in acute liver failure.

Unlabelled: Tissue engineering with scaffolds to form transplantable organs is of wide interest. Decellularized tissues have been tested for this purpose, although supplies of healthy donor tissues, vascular recellularization for perfusion, and tissue homeostasis in engineered organs pose challenges. We hypothesized that decellularized human placenta will be suitable for tissue engineering.

Demonstrating Potential of Cell Therapy for Wilson's Disease with the Long-Evans Cinnamon Rat Model.

Wilson's disease (WD) is characterized by the inability to excrete copper (Cu) from the body with progressive tissue injury, especially in liver and brain. The molecular defect in WD concerns mutations in ATP7B gene leading to loss of Cu transport from the hepatocyte to the bile canaliculus. While drugs, e.

Comprehensive Assessment of Oxidatively Induced Modifications of DNA in a Rat Model of Human Wilson's Disease.

Defective copper excretion from hepatocytes in Wilson's disease causes accumulation of copper ions with increased generation of reactive oxygen species via the Fenton-type reaction. Here we developed a nanoflow liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry coupled with the isotope-dilution method for the simultaneous quantification of oxidatively induced DNA modifications. This method enabled measurement, in microgram quantities of DNA, of four oxidative stress-induced lesions, including direct ROS-induced purine cyclonucleosides (cPus) and two exocyclic adducts induced by byproducts of lipid peroxidation, i.

Endogenous antiviral microRNAs determine permissiveness for hepatitis B virus replication in cultured human fetal and adult hepatocytes.

Superior cell culture models for hepatitis B virus (HBV) will help advance insights into host-virus interactions. To identify mechanisms regulating HBV replication, this study used cultured human HepG2 cells and adult or fetal hepatocytes transduced with adenoviral vector to express HBV upstream of green fluorescent protein. The vector efficiently transduced all cell types.

Diversity of HIV type 1 long terminal repeat (LTR) sequences following mother-to-child transmission in North India.

We genetically characterized the extent of variation in HIV-1 LTR sequences from 11 mother-to-child transmission (MTCT) pairs from HIV-1-infected individuals from North India. Nine pairs were found to be infected with subtype C virus whereas two pairs were infected with subtype B virus. They harbored the characteristic three and two NF-κB sites, respectively.

Genetic and functional analysis of HIV-1 Rev Responsive Element (RRE) sequences from North-India.

HIV-1 Rev protein regulates the expression of HIV-1 transcripts by binding to a highly structured stem loop structure called the Rev Responsive Element (RRE) present in the genomic and partially spliced RNAs. Genetic variation in this structure is likely to affect binding of Rev protein and ultimately overall gene expression and replication. We characterized RRE sequences from 13 HIV-1 infected individuals from North India which also included two mother-child pairs following vertical transmission.

Global HIV-1 molecular epidemiology with special reference to genetic analysis of HIV-1 subtypes circulating in North India: functional and pathogenic implications of genetic variation.

HIV-1 displays extensive genetic diversity globally which poses challenge in designing a suitable antigen/immunogen to provoke desired protective immune response in host. HIV-1 mediated pathogenesis is complex and involves host genes, virus genes and other factors. A number of genetic subtypes have been identified based on sequence variations, largely in envelope region.

Potent knockdown of the X RNA of hepatitis B by a novel chimeric siRNA-ribozyme construct and modulation of intracellular target RNA by selectively disabled mutants.

A multitarget approach is needed for effective gene silencing that combines more than one antiviral strategy. With this in mind, we designed a wild-type (wt) and selectively disabled chimeric mutant (mt) constructs that consisted of small hairpin siRNA joined by a short intracellular cleavable linker to a known hammerhead ribozyme, both targeted against the full-length X RNA of hepatitis B. These chimeric RNAs possessed the ability to cleave the target RNA under in vitro conditions and were efficiently processed at the cleavable site.

HIV-1 VprB and C RNA cleavage by potent 10-23 DNAzymes that also cause reversal of G2 cell cycle arrest mediated by Vpr genes.

Accessory Vpr protein of HIV-1 is known to influence several key cellular functions that also impacts on the HIV-1 replication cycle. Besides other activities, it alone causes cell cycle arrest at the G2 phase and thus potentially contribute to the overall pathology. We designed several 10-23 catalytic motifs containing DNAzymes (Dzs) against the full-length Vpr gene from subtype B and checked its activity against VprC gene from one of the Indian HIV-1 isolates.