Resistin secreted from macrophages may contribute to atherogenesis by virtue of its effects on vascular endothelial cells and smooth muscle cells in humans.
Osteopontin (OPN) was initially identified in osteoblasts as a mineralization-modulatory matrix protein. Recently, OPN has been studied as a multifunctional protein that is upregulated in a variety of acute and chronic inflammatory conditions, such as wound healing, fibrosis, autoimmune disease, and atherosclerosis. OPN is highly expressed at sites with atherosclerotic plaques, especially those associated with macrophages and foam cells. In the context of atherosclerosis, OPN is generally regarded as a proinflammatory and proatherogenic molecule. However, the role of OPN in vascular calcification (VC), which is closely related to chronic and active inflammation, is that of a negative regulator because it is an inhibitor of calcification and an active inducer of decalcification. OPN expression and its regulatory molecular mechanisms remain elusive during the process of VC. Therefore, further research with regard to the role of OPN in diseases associated with VC is needed to identify potential OPN-related therapeutic targets.
-Catenin is a transcriptional regulator of several genes involved in survival and proliferation. Although previous studies suggest that -catenin may be involved in the process of preconditioning and healing after myocardial infarction (MI), little is known regarding the role of -catenin in cardiomyocytes and cardiac fibroblasts. We investigated the role of -catenin in cardiomyocytes and cardiac fibroblasts and whether -catenin overexpression could reduce MI size. Adenovirus-mediated gene transfer of nonphosphorylatable constitutively active -catenin (Ad-catenin) decreased apoptosis in cardiomyocytes and cardiac fibroblasts with increased expression of survivin and Bcl-2. Although Ad-catenin increased the percentage of cells in the S phase with enhanced expression of cyclin D1 and E2 in both cell types, the increase in cell number was only evident in cardiac fibroblasts, whereas hypertrophy and binuclear cells were more prominent in cardiomyocytes. All of these effects of -catenin gene transfer were blocked by inhibition of its nuclear translocation. Furthermore, Ad-catenin enhanced the expression of vascular endothelial growth factor in both cells and induced differentiation of cardiac fibroblasts into myofibroblasts. In a rat MI model, injection of Ad-catenin into the infarct border zone resulted in a significantly decreased MI size with anti-apoptotic effect and cell cycle activation in both cardiomyocytes and myofibroblasts. -Catenin may play an important role in the healing process after MI by promoting survival and cell cycle not only in cardiomyocytes but also in cardiac fibroblasts with its differentiation into myofibroblasts.-Catenin is known to have dual functions. Membranebound -catenin maintains tissue architecture and cell polarity at adherens junctions by linking the cadherin cytoplasmic tail to the actin cytoskeleton (1). Cytoplasmic -catenin translocates into the nucleus where it forms a complex with transcription factors of Tcf/Lef family and activates the expression of specific genes involved in cell survival and proliferation (1, 2). Glycogen-synthase kinase 3 (GSK3) 3 constitutively phosphorylates cytoplasmic -catenin resulting in proteosomal degradation (3), and Wnt signaling inhibits GSK3, leading to cytoplasmic accumulation of -catenin (4).Although the critical roles of -catenin during development (5) and in neoplastic disease have been well described previously (6), relatively little is known about the role of -catenin in cardiomyocytes and cardiac fibroblasts, which are not only the principal cells comprising the myocardium but also key cells involved in remodeling after myocardial infarction (MI). Recent studies have suggested that -catenin is capable of regulating survival/apoptosis and hypertrophy of cardiomyocytes (7,8). The inactivation of GSK3 by statins has been shown to inhibit cardiomyocyte apoptosis (7), whereas activated GSK3 was shown to attenuate cardiac hypertrophy in vivo (8). In addition, Wnt/-catenin pathways have also been implicated in fibroblast p...
X-linked adrenoleukodystrophy (X-ALD), caused by an ABCD1 mutation, is a progressive neurodegenerative disorder associated with the accumulation of very long-chain fatty acids (VLCFA). Cerebral inflammatory demyelination is the major feature of childhood cerebral ALD (CCALD), the most severe form of ALD, but its underlying mechanism remains poorly understood. Here, we identify the aberrant production of cholesterol 25-hydroxylase (CH25H) and 25-hydroxycholesterol (25-HC) in the cellular context of CCALD based on the analysis of ALD patient-derived induced pluripotent stem cells and ex vivo fibroblasts. Intriguingly, 25-HC, but not VLCFA, promotes robust NLRP3 inflammasome assembly and activation via potassium efflux-, mitochondrial reactive oxygen species (ROS)- and liver X receptor (LXR)-mediated pathways. Furthermore, stereotaxic injection of 25-HC into the corpus callosum of mouse brains induces microglial recruitment, interleukin-1β production, and oligodendrocyte cell death in an NLRP3 inflammasome-dependent manner. Collectively, our results indicate that 25-HC mediates the neuroinflammation of X-ALD via activation of the NLRP3 inflammasome.
Background DYRK1A maps to the Down syndrome critical region at 21q22. Mutations in this kinase-encoding gene have been reported to cause microcephaly associated with either intellectual disability or autism in humans. Intellectual disability accompanied by microcephaly was recapitulated in a murine model by overexpressing Dyrk1a which mimicked Down syndrome phenotypes. However, given embryonic lethality in homozygous knockout (KO) mice, no murine model studies could present sufficient evidence to link Dyrk1a dysfunction with autism. To understand the molecular mechanisms underlying microcephaly and autism spectrum disorders (ASD), we established an in vivo dyrk1aa KO model using zebrafish.MethodsWe identified a patient with a mutation in the DYRK1A gene using microarray analysis. Circumventing the barrier of murine model studies, we generated a dyrk1aa KO zebrafish using transcription activator-like effector nuclease (TALEN)-mediated genome editing. For social behavioral tests, we have established a social interaction test, shoaling assay, and group behavior assay. For molecular analysis, we examined the neuronal activity in specific brain regions of dyrk1aa KO zebrafish through in situ hybridization with various probes including c-fos and crh which are the molecular markers for stress response.ResultsMicroarray detected an intragenic microdeletion of DYRK1A in an individual with microcephaly and autism. From behavioral tests of social interaction and group behavior, dyrk1aa KO zebrafish exhibited social impairments that reproduce human phenotypes of autism in a vertebrate animal model. Social impairment in dyrk1aa KO zebrafish was further confirmed by molecular analysis of c-fos and crh expression. Transcriptional expression of c-fos and crh was lower than that of wild type fish in specific hypothalamic regions, suggesting that KO fish brains are less activated by social context.ConclusionsIn this study, we established a zebrafish model to validate a candidate gene for autism in a vertebrate animal. These results illustrate the functional deficiency of DYRK1A as an underlying disease mechanism for autism. We also propose simple social behavioral assays as a tool for the broader study of autism candidate genes.Electronic supplementary materialThe online version of this article (10.1186/s13229-017-0168-2) contains supplementary material, which is available to authorized users.
Alpha-synuclein is a pathological component of Parkinson's disease by constituting the filamentous component of Lewy bodies. Phthalocyanine (Pc) effects on the amyloidosis of alpha-synuclein have been examined. The copper complex of phthalocyanine tetrasulfonate (PcTS-Cu(2+)) caused the self-oligomerization of alpha-synuclein while Pc-Cu(2+) did not affect the protein, indicating that introduction of the sulfonate groups was critical for the selective protein interaction. The PcTS-Cu(2+) interaction with alpha-synuclein has occurred predominantly at the N-terminal region of the protein with a K(d) of 0.83 microM apart from the hydrophobic NAC (non-Abeta component of Alzheimer's disease amyloid) segment. Phthalocyanine tetrasulfonate (PcTS) lacking the intercalated copper ion also showed a considerable affinity toward alpha-synuclein with a K(d) of 3.12 microM, and its binding site, on the other hand, was located at the acidic C-terminus. These mutually exclusive interactions between PcTS and PcTS-Cu(2+) toward alpha-synuclein resulted in distinctive features on the kinetics of protein aggregation, morphologies of the final aggregates, and their in vitro cytotoxicities. The PcTS actually suppressed the fibrous amyloid formation of alpha-synuclein, but it produced the chopped-wood-looking protein aggregates. The aggregates showed rather low toxicity (9.5%) on human neuroblastoma cells (SH-SY5Y). In fact, the PcTS was shown to effectively rescue the cell death of alpha-synuclein overexpressing cells caused by the lactacystin treatment as a proteasome inhibitor. The anti-aggregative and anti-amyloidogenic properties of PcTS were also demonstrated with alcohol dehydrogenase, glutathione S-transferase, and amyloid beta/A4 protein under their aggregative conditions. The PcTS-Cu(2+), on the other hand, promoted the protein aggregation of alpha-synuclein, which gave rise to the fibrillar protein aggregates whose cytotoxicity became significant to 35.8%. Taken together, the data provided in this study indicate that PcTS/PcTS-Cu(2+) could be considered as possible candidates for the development of therapeutic or prophylactic strategies against the alpha-synuclein-related neurodegenerative disorders.
Studying the effects of saturated and unsaturated fatty acids on biological and model (liposomes) membranes could provide insight into the contribution of biophysical effects on the cytotoxicity observed with saturated fatty acids. In vitro experiments suggest that unsaturated fatty acids, such as oleate and linoleate, are less toxic, and have less of an impact on the membrane fluidity. To understand and assess the biophysical changes in the presence of the different fatty acids, we performed computational analyses of model liposomes with palmitate, oleate, and linoleate. The computational results indicate that the unsaturated fatty acid chain serves as a membrane stabilizer by preventing changes to the membrane fluidity. Based on a Voronoi tessellation analysis, unsaturated fatty acids have structural properties that can reduce the lipid ordering within the model membranes. In addition, hydrogen bond analysis indicates a more uniform level of membrane hydration in the presence of oleate and linoleate as compared to palmitate. Altogether, these observations from the computational studies provide a possible mechanism by which unsaturated fatty acids minimize biophysical changes and protect the cellular membrane and structure. To corroborate our findings, we also performed a liposomal leakage study to assess how the different fatty acids alter the membrane integrity of liposomes. This showed that palmitate, a saturated fatty acid, caused greater destabilization of liposomes (more “leaky”) than oleate, an unsaturated fatty acid.
Background-Cell-based therapies to augment endothelial cells (ECs) hold great therapeutic promise. Here, we report a novel approach to generate functional ECs directly from adult fibroblasts. Methods and Results-Eleven candidate genes that are key regulators of endothelial development were selected. Green fluorescent protein (GFP)-negative skin fibroblasts were prepared from Tie2-GFP mice and infected with lentiviruses allowing simultaneous overexpression of all 11 factors. Tie2-GFP + cells (0.9%), representing Tie2 gene activation, were detected by flow cytometry. Serial stepwise screening revealed 5 key factors (Foxo1, Er71, Klf2, Tal1, and Lmo2) that were required for efficient reprogramming of skin fibroblasts into Tie2-GFP + cells (4%). This reprogramming strategy did not involve pluripotency induction because neither Oct4 nor Nanog was expressed after 5 key factor transduction. Tie2-GFP + cells were isolated using fluorescence-activated cell sorting and designated as induced ECs (iECs). iECs exhibited endothelium-like cobblestone morphology and expressed EC molecular markers. iECs possessed endothelial functions such as Bandeiraea simplicifolia-1 lectin binding, acetylated low-density lipoprotein uptake, capillary formation on Matrigel, and nitric oxide production. The epigenetic profile of iECs was similar to that of authentic ECs because the promoters of VE-cadherin and Tie2 genes were demethylated. mRNA profiling showed clustering of iECs with authentic ECs and highly enriched endothelial genes in iECs. In a murine model of hind-limb ischemia, iEC implantation increased capillary density and enhanced limb perfusion, demonstrating the in vivo viability and functionality of iECs. Conclusions-We
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