Monocyte chemotactic protein-1 (MCP-1) has been recognized as an angiogenic chemokine. The molecular mechanism of MCP-1-mediated angiogenesis remains unknown. We recently identified a novel ...transcription factor, designated MCP-1-induced protein (MCPIP), in human monocytes after treatment with MCP-1. We investigated whether MCP-1-induced angiogenesis is mediated via MCPIP. Treatment of human umbilical vein endothelial cells (HUVECs) with MCP-1 induced expression of MCPIP and capillary-like tube formation. Knockdown of MCPIP by small interfering RNA (siRNA) suppressed MCP-1-induced angiogenesis-related gene VEGF and HIF-1α expression as well as tube formation. Transfection of HUVECs with an MCPIP expression vector induced angiogenesis-related genes and tube formation. Chromatin immunoprecipitation analysis revealed that cadherin (cdh) 12 and cdh19 are in vivo targets of MCPIP. Transfection of HUVECs with MCPIP expression vector activated the expression of cdh12 and cdh19 genes. Knockdown of cdh12 or cdh19 expression markedly inhibited MCPIP-induced capillary-like tube formation. Moreover, knockdown of MCPIP also significantly suppressed MCP-1-induced cdh12 and cdh19 gene expression. Our data strongly suggest that MCP-1-induced angiogenesis is mediated via MCPIP, at least in part through transcriptional activation of cdh12 and cdh19.
Activated macrophages play an important role in many inflammatory diseases. However, the molecular mechanisms controlling macrophage activation are not completely understood. Here we report that a ...novel CCCH-zinc finger protein family, MCPIP1, 2, 3, and 4, encoded by four genes, Zc3h12a, Zc3h12b, Zc3h12c, and Zc3h12d, respectively, regulates macrophage activation. Northern blot analysis revealed that the expression of MCPIP1 and MCPIP3 was highly induced in macrophages in response to treatment with lipopolysaccharide (LPS). Although not affecting cell surface marker expression and phagocytotic function, overexpression of MCPIP1 significantly blunted LPS-induced inflammatory cytokine and NO2·¯ production as well as their gene expression. Conversely, short interfering RNA-mediated reduction in MCPIP1 augmented LPS-induced inflammatory gene expression. Further studies demonstrated that MCPIP1 did not directly affect the mRNA stability of tumor necrosis factor α and monocyte chemoattractant protein 1 (MCP-1) but strongly inhibited LPS-induced tumor necrosis factor α and inducible nitric-oxide synthase promoter activation. Moreover, we found that forced expression of MCPIP1 significantly inhibited LPS-induced nuclear factor-κB activation. These results identify MCP-induced proteins, a novel CCCH-zinc finger protein family, as negative regulators in macrophage activation and may implicate them in host immunity and inflammatory diseases.
Common genetic variants at the
RIN3
locus on chromosome 14q32 predispose to Paget’s disease of bone (PDB) but the mechanisms by which they do so are unknown. Here, we analysed the skeletal phenotype ...of female mice with targeted inactivation of the mouse
Rin3
gene (
Rin3
−/−
) as compared with wild-type littermates. The
Rin3
−
/
−
mice had higher trabecular bone volume (BV/TV%) compared with wild type. Mean ± standard deviation values at the distal femur at 8 weeks were 9.0 ± 2.5 vs. 7.0 ± 1.5 (
p
= 0.002) and at 52 weeks were 15.8 ± 9.5 vs. 8.5 ± 4.2 (
p
= 0.002). No differences were observed in femoral cortical bone parameters with the exception of marrow diameter which was significantly smaller in 52-week-old
Rin3
−
/
−
mice compared to wild type: (0.43 mm ± 0.1 vs. 0.57 mm ± 0.2 (
p
= 0.001). Bone histomorphometry showed a lower osteoclast surface / bone surface (Oc.S/BS%) at 8 weeks in
Rin3
−
/
−
mice compared to wild type (24.1 ± 4.7 vs. 29.7 ± 6.6;
p
= 0.025) but there were no significant differences in markers of bone formation at this time. At 52 weeks, Oc.S/BS did not differ between genotypes but single labelled perimeter (SL.Pm/B.Pm (%)) was significantly higher in
Rin3
−
/
−
mice (24.4 ± 6.4 vs. 16.5 ± 3.8,
p
= 0.003). We conclude that
Rin3
negatively regulates trabecular bone mass in mice by inhibiting osteoclastic bone resorption and favouring bone formation. Our observations also suggest that the variants that predispose to PDB in humans probably do so by causing a gain-in-function of
RIN3
.
Endoplasmic reticulum (ER) stress has been found to be associated with neurodegenerative diseases and diabetes mellitus. Whether ER stress is involved in the development of heart disease is not ...known. Cardiac-specific expression of monocyte chemoattractant protein-1 (MCP-1) in mice causes the development of ischemic heart disease. Here we report that microarray analysis of gene expression changes in the heart of these transgenic mice revealed that a cluster of ER stress-related genes was transcriptionally activated in the heart during the development of ischemic heart disease. The gene array results were verified by quantitative real-time PCR that showed highly elevated transcript levels of genes involved in unfolded protein response such as ER and cytoplasmic chaperones, oxidoreductases, protein disulfide isomerase (PDI) family, and ER-associated degradation system such as ubiquitin. Immunoblot analysis confirmed the expression of chaperones, PDI, and ubiquitin. Immunohistochemical analyses showed that ER stress proteins were associated mainly with the degenerating cardiomyocytes. A novel ubiquitin fold modifier (Ufm1) that has not been previously associated with ER stress and not found to be induced under any condition was also found to be upregulated in the hearts of MCP mice (transgenic mice that express MCP-1 specifically in the heart). The present results strongly suggest that activation of ER stress response is involved in the development of ischemic heart disease in this murine model.
The magnetization of mesenchymal stem cells (MSC) has the potential to aid tissue engineering approaches by allowing tracking, targeting, and local retention of cells at the site of tissue damage. ...Commonly used methods for magnetizing cells include optimizing uptake and retention of superparamagnetic iron oxide nanoparticles (SPIONs). These appear to have minimal detrimental effects on the use of MSC function as assessed by in vitro assays. The cellular content of magnetic nanoparticles (MNPs) will, however, decrease with cell proliferation and the longer-term effects on MSC function are not entirely clear. An alternative approach to magnetizing MSCs involves genetic modification by transfection with one or more genes derived from
AMB-1, a magnetotactic bacterium that synthesizes single-magnetic domain crystals which are incorporated into magnetosomes. MSCs with either or
and
genes are followed by bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by magnetic resonance (MR) and which have no deleterious effects on MSC proliferation, migration, or differentiation. The stable transfection of magnetosome-associated genes in MSCs promotes assimilation of magnetic nanoparticle synthesis into mammalian cells with the potential to allow MR-based cell tracking and, through external or internal magnetic targeting approaches, enhanced site-specific retention of cells for tissue engineering.
Paget’s disease of bone (PDB) is a common disease characterized by osteoclast activation that leads to various skeletal complications. Susceptibility to PDB is mediated by a common variant at the ...optineurin (OPTN) locus, which is associated with reduced levels of mRNA. However, it is unclear how this leads to the development of PDB. Here, we show that OPTN acts as a negative regulator of osteoclast differentiation in vitro and that mice with a loss-of-function mutation in Optn have increased osteoclast activity and bone turnover. Osteoclasts derived from Optn mutant mice have an increase in NF-κB activation and a reduction in interferon beta expression in response to RANKL when compared to wild-type mice. These studies identify OPTN as a regulator of bone resorption and are consistent with a model whereby genetically determined reductions in OPTN expression predispose to PDB by enhancing osteoclast differentiation.
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•Susceptibility to Paget's disease is associated with reduced optineurin expression•Optineurin knockdown enhances osteoclast differentiation•Loss of optineurin function increases bone turnover in vivo•Optineurin inhibits osteoclast formation by modulating NF-κB and IFN-β signaling
Using mouse models, Obaid et al. identify a role of optineurin in bone metabolism as a negative regulator of osteoclast differentiation. Loss of optineurin function leads to increased bone turnover in mice, suggesting a mechanism by which genetic variants in optineurin predispose to Paget’s disease of bone.
Gorham-Stout disease is a rare condition characterized by vascular proliferation and the massive destruction of bone tissue. With less than 400 cases in the literature of Gorham-Stout syndrome, we ...performed a unique study combining whole-genome sequencing and RNA-Seq to probe the genomic features and differentially expressed pathways of a presented case, revealing new possible drivers and biomarkers of the disease.
We present a case report of a white 45-year-old female patient with marked bone loss of the left humerus associated with vascular proliferation, diagnosed with Gorham-Stout disease. The analysis of whole-genome sequencing showed a dominance of large structural DNA rearrangements. Particularly, rearrangements in chromosomes seven, twelve, and twenty could contribute to the development of the disease, especially a gene fusion involving ATG101 that could affect macroautophagy. The study of RNA-sequencing data from the patient uncovered the PI3K/AKT/mTOR pathway as the most affected signaling cascade in the Gorham-Stout lesional tissue. Furthermore, M2 macrophage infiltration was detected using immunohistochemical staining and confirmed by deconvolution of the RNA-seq expression data.
The way that DNA and RNA aberrations lead to Gorham-Stout disease is poorly understood due to the limited number of studies focusing on this rare disease. Our study provides the first glimpse into this facet of the disease, exposing new possible therapeutic targets and facilitating the clinicopathological diagnosis of Gorham-Stout disease.
Doxorubicin (Dox) is known to cause cardiomyopathy and congestive heart failure upon chronic administration. The mechanisms underlying these toxicities remain uncertain but have been attributed, at ...least in part, by induction of cardiac cell apoptosis. Fas ligation with its cognate ligand (FasL) induces apoptosis and activates cellular inflammatory responses associated with tissue injury. We determined whether interruption of Fas/FasL interaction by cardiac-targeted expression of soluble Fas (sFas), a competitive inhibitor of FasL, would protect against Dox chronic cardiotoxicity in mice. Wild-type (WT) and sFas transgenic mice were administrated intravenously with 4 mg/kg Dox or with an equivalent volume of saline twice a week for a total of 10 injections. There were 25% mortality in WT mice, but no death was observed in sFas mice during the period of Dox treatment. Echocardiographic evaluation revealed a significant decrease in left ventricle fractional shortening after Dox treatment in WT mice but not in sFas mice. WT mice treated with Dox developed extensive myocardial cytoplasmic vacuolization, apoptosis, and interstitial fibrosis, which were much less or absent in sFas mice. The increased inducible nitric oxide synthase expression, nitric oxide production, superoxide generation, and peroxynitrite formation after Dox treatment in WT mice were attenuated by sFas expression. sFas expression also attenuated Dox-mediated induction of proinflammatory cytokines, tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-6 in the myocardium. These observations indicate that FasL is an important mediator in Dox-associated cardiotoxicity by generating reactive oxygen and nitrogen species.
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