A High-Throughput In Situ Method for Estimation of Hepatocyte Nuclear Ploidy in Mice.

When the liver is injured, hepatocyte numbers decrease, while cell size, nuclear size and ploidy increase. The expansion of non-parenchymal cells such as cholangiocytes, myofibroblasts, progenitors and inflammatory cells also indicate chronic liver damage, tissue remodeling and disease progression. In this protocol, we describe a simple high-throughput approach for calculating changes in the cellular composition of the liver that are associated with injury, chronic disease and cancer.

CliqueMS: a computational tool for annotating in-source metabolite ions from LC-MS untargeted metabolomics data based on a coelution similarity network.

Motivation: The analysis of biological samples in untargeted metabolomic studies using LC-MS yields tens of thousands of ion signals. Annotating these features is of the utmost importance for answering questions as fundamental as, e.g.

Insulin resistance disrupts epithelial repair and niche-progenitor Fgf signaling during chronic liver injury.

Insulin provides important information to tissues about feeding behavior and energy status. Defective insulin signaling is associated with ageing, tissue dysfunction, and impaired wound healing. In the liver, insulin resistance leads to chronic damage and fibrosis, but it is unclear how tissue-repair mechanisms integrate insulin signals to coordinate an appropriate injury response or how they are affected by insulin resistance.

Autophagy is a gatekeeper of hepatic differentiation and carcinogenesis by controlling the degradation of Yap.

Activation of the Hippo pathway effector Yap underlies many liver cancers, however no germline or somatic mutations have been identified. Autophagy maintains essential metabolic functions of the liver, and autophagy-deficient murine models develop benign adenomas and hepatomegaly, which have been attributed to activation of the p62/Sqstm1-Nrf2 axis. Here, we show that Yap is an autophagy substrate and mediator of tissue remodeling and hepatocarcinogenesis independent of the p62/Sqstm1-Nrf2 axis.

Contributions of metabolic dysregulation and inflammation to nonalcoholic steatohepatitis, hepatic fibrosis, and cancer.

Purpose Of Review: We review accumulating evidence that nonalcoholic steatohepatitis (NASH), a more advanced form of nonalcoholic fatty liver disease (NAFLD), predisposes patients to the risk of developing hepatocellular carcinoma (HCC), and we summarize recent advances in the elucidation of cancer-promoting pathways in NASH. We highlight the potential role of progenitor cells and hepatic stellate cells (HSCs) in promoting the early events that could culminate in cancer, as well as the emerging contribution of the gut-liver axis in promoting inflammation, senescence, and tumor growth in NASH and HCC. Finally, we review the role of bile acid receptors, vitamin D, and protective cellular pathways such as autophagy.

The use of nanofibrillar cellulose hydrogel as a flexible three-dimensional model to culture human pluripotent stem cells.

Human embryonic stem cells and induced pluripotent stem cells have great potential in research and therapies. The current in vitro culture systems for human pluripotent stem cells (hPSCs) do not mimic the three-dimensional (3D) in vivo stem cell niche that transiently supports stem cell proliferation and is subject to changes which facilitate subsequent differentiation during development. Here, we demonstrate, for the first time, that a novel plant-derived nanofibrillar cellulose (NFC) hydrogel creates a flexible 3D environment for hPSC culture.

A central role for the ERK-signaling pathway in controlling Schwann cell plasticity and peripheral nerve regeneration in vivo.

Following damage to peripheral nerves, a remarkable process of clearance and regeneration takes place. Axons downstream of the injury degenerate, while the nerve is remodeled to direct axonal regrowth. Schwann cells are important for this regenerative process.

Comparative methylome analysis of benign and malignant peripheral nerve sheath tumors.

Aberrant DNA methylation (DNAm) was first linked to cancer over 25 yr ago. Since then, many studies have associated hypermethylation of tumor suppressor genes and hypomethylation of oncogenes to the tumorigenic process. However, most of these studies have been limited to the analysis of promoters and CpG islands (CGIs).

A genetic screen for anchorage-independent proliferation in mammalian cells identifies a membrane-bound neuregulin.

Anchorage-independent proliferation is a hallmark of oncogenic transformation and is thought to be conducive to proliferation of cancer cells away from their site of origin. We have previously reported that primary Schwann cells expressing the SV40 Large T antigen (LT) are not fully transformed in that they maintain a strict requirement for attachment, requiring a further genetic change, such as oncogenic Ras, to gain anchorage-independence. Using the LT-expressing cells, we performed a genetic screen for anchorage-independent proliferation and identified Sensory and Motor Neuron Derived Factor (SMDF), a transmembrane class III isoform of Neuregulin 1.

NF1 loss disrupts Schwann cell-axonal interactions: a novel role for semaphorin 4F.

Neurofibromatosis type 1 (NF1) patients develop neurofibromas, tumors of Schwann cell origin, as a result of loss of the Ras-GAP neurofibromin. In normal nerves, Schwann cells are found tightly associated with axons, while loss of axonal contact is a frequent and important early event in neurofibroma development. However, the molecular basis of this physical interaction or how it is disrupted in cancer remains unclear.

c-Jun is a negative regulator of myelination.

Schwann cell myelination depends on Krox-20/Egr2 and other promyelin transcription factors that are activated by axonal signals and control the generation of myelin-forming cells. Myelin-forming cells remain remarkably plastic and can revert to the immature phenotype, a process which is seen in injured nerves and demyelinating neuropathies. We report that c-Jun is an important regulator of this plasticity.

Treating leprosy: an Erb-al remedy?

The leprosy pathogen Mycobacterium leprae attacks Schwann cells in the peripheral nervous system, causing them to demyelinate. Recent work by Tapinos et al. shows that a direct mechanism of demyelination induced by M.

Identification of a novel melanocortin 2 receptor splice variant in murine adipocytes: implications for post-transcriptional control of expression during adipogenesis.

The ACTH receptor melanocortin 2 receptor (MC2-R) is a G-protein-coupled receptor principally expressed in the adrenal cortex and the adipocyte, where it stimulates steroidogenesis and lipolysis respectively. The coding region of the murine gene is encoded by a single exon, although three upstream non-coding exons have been documented, one of which is incorporated by alternative splicing in adrenal cells. We have detected a novel transcript in adipocytes, which includes a previously unidentified 86 bp exon upstream of the coding region.

A CCAAT/enhancer-binding protein site at -87 is required for the activation of a novel murine melanocortin 2-receptor promoter at late stages during adipogenesis.

The peptide hormone ACTH stimulates lipolysis and suppresses leptin production in adipocytes via the G protein-coupled receptor, melanocortin 2 receptor (MC2-R). We have shown previously that peroxisome proliferator-activated receptor-gamma2 is the primary factor responsible for transactivation of the already identified murine MC2-R promoter in the differentiating 3T3-L1 adipocyte cell line. In this study we show that despite the activity of this promoter being transient during differentiation, MC2-R message remains elevated at later time points during adipogenesis.

Hijacking the ERK signaling pathway: Mycobacterium leprae shuns MEK to drive the proliferation of infected Schwann cells.

Schwann cells are the target of Mycobacterium leprae, the pathogen responsible for leprosy. Once inside the cell, M. leprae activates the host's proliferative machinery, thereby increasing the number of cells susceptible to infection.

Constitutive activation of the human ACTH receptor resulting from a synergistic interaction between two naturally occurring missense mutations in the MC2R gene.

Two mutations in the same allele of the ACTH receptor (melanocortin 2 receptor, MC2R) associated with clinical hypersensitivity to ACTH have been described in a single case report. Using a stable Y6 cell expression system, we demonstrate that either the C21R or S247G mutations alone produce an inactive receptor with loss of ligand binding and responsiveness. However, the presence of both mutations in the same molecule leads to a receptor with a highly significant elevation in constitutive activity (basal cAMP accumulation for wild type expressing cells 199 +/- 11 pmol/mg protein; double mutant: 374 +/- 29 pmol/mg protein, P < 0.

A peroxisome proliferator-response element in the murine mc2-r promoter regulates its transcriptional activation during differentiation of 3T3-L1 adipocytes.

Adrenocorticotropic hormone can stimulate lipolysis and suppress leptin expression in murine adipocytes. These effects are mediated via the melanocortin 2 receptor (MC2-R), which is expressed when 3T3-L1 cells are induced to undergo adipogenesis. In this study, we have characterized the mc2-r promoter in the murine adipocyte, one of the few extra-adrenal sites of expression and a cell type that lacks steroidogenic factor 1 (SF-1), a transcription factor that is required for mc2-r expression in adrenal cells.

Expression, desensitization, and internalization of the ACTH receptor (MC2R).

Research into the functions and mechanisms of action of the melanocortin 2 receptor (MC2R) has been severely hampered by difficulties in expressing this gene in heterologous cells. This probably arises because of the need for a cofactor for cell surface expression. Using either the Y1 cell line that expresses endogenous MC2R or the Y6 cell line that expresses this putative expression factor, we have explored the mechanisms of desensitization and internalization after agonist stimulation.