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Myeloproliferative neoplasms are diseases that arise in the stem cells of the blood. In a recent paper published in Nature, Arranz et al. demonstrated that abrogation of sympathetic nerve fibers reduced bone marrow Nestin+ mesenchymal cells, which in turn led to an expansion of hematopoietic stem cells and progression of myeloproliferative neoplasms.
The investigation of virus-induced liver disease and hepatocellular carcinoma needs small animal models modeling hepatitis C virus (HCV) infection and liver disease biology. A recent study published in Cell Research reports a novel mouse model which is permissive for chronic HCV infection and shows chronic liver injury including inflammation, steatosis and fibrosis.
The aryl hydrocarbon receptor (AhR) is an important regulator of the immune response. A report by Puccetti and coworkers describes a regulatory pathway by which L-kynurenine (L-Kyn) produced by tryptophan 2,3-dioxygenase 2 (TDO2) activates AhR in cells of the innate immune system to limit endotoxin-triggered inflammation through a mechanism that involves the non-enzymatic anti-inflammatory activities of indoleamine 2,3-dioxygenase 1 (IDO1).
Ultraviolet radiation (UVR) is a major risk factor for melanoma development, but it has been unclear exactly how UVR leads to melanomagenesis. In a recent publication in Nature, Viros et al. identify TP53/Trp53 as a UVR-target gene in melanoma and show that UVR-induced TP53/Trp53 mutations accelerate BRAF(V600E)-driven melanomagenesis.
In recent years, researchers worldwide have developed protocols to efficiently differentiate skeletal myogenic cells from human pluripotent stem cells through either ectopic gene expression or the use of small molecules. These stem cell-derived myogenic cells provide new avenues for the study of muscle-related diseases, drug screening and are potentially a new tool for cell therapy against muscular dystrophies.
Accumulating evidence indicates that the mesenchymal-epithelial transition (MET) and epithelial-mesenchymal transition (EMT) are basic mechanisms for cell fate conversion and may help us understand both physiologic and pathologic processes such as development and carcinogenesis. Here, we further suggest that mammalian cells fall into two grand divisions, mesenchymal or epithelial; interconversions between these two grand divisions through EMT/MET resonate with some ancient Chinese philosophic ideas.
