Thoracic aortic aneurysms leading to type A dissections (TAAD) can be inherited in isolation or in association with genetic syndromes, such as Marfan syndrome and Loeys-Dietz syndrome. When TAAD occurs in the absence of syndromic features, it is inherited in an autosomal dominant manner with decreased penetrance and variable expression, the disease is referred to as familial TAAD. Familial TAAD exhibits significant clinical and genetic heterogeneity. The first genes identified to cause TAAD were FBN1, TGFBR2, and TGFBR1. The identification and characterization of these genes suggested that increased TGF-beta signaling plays a role in pathogenesis. The recent discovery that mutations in the vascular smooth muscle cell (SMC)-specific beta-myosin (MYH11) and alpha-actin (ACTA2) can also cause this disorder has focused attention on the importance of the maintenance of SMC contractile function in preserving aortic structure and preventing TAAD.

DNMT3 proteins are de novo DNA methyltransferases that are responsible for the establishment of DNA methylation patterns in mammalian genomes. Here, we have determined the crystal structures of the ATRX-DNMT3-DNMT3L (ADD) domain of DNMT3A in an unliganded form and in a complex with the amino-terminal tail of histone H3. Combined with the results of biochemical analysis, the complex structure indicates that DNMT3A recognizes the unmethylated state of lysine 4 in histone H3. This finding indicates that the recruitment of DNMT3A onto chromatin, and thereby de novo DNA methylation, is mediated by recognition of the histone modification state by its ADD domain. Furthermore, our biochemical and nuclear magnetic resonance data show mutually exclusive binding of the ADD domain of DNMT3A and the chromodomain of heterochromatin protein 1a to the H3 tail. These results indicate that de novo DNA methylation by DNMT3A requires the alteration of chromatin structure.

Objective-Vascular endothelial growth factor (VEGF) plays an important role in inducing angiogenesis. Mesenchymal stem cells (MSCs) may have potential for differentiation to several types of cells, including myocytes. We hypothesized that transplantation of VEGF-expressing MSCs could effectively treat acute myocardial infarction (MI) by providing enhanced cardioprotection, followed by angiogenic effects in salvaging ischemic myocardium. Methods and Results-The human VEGF 165 gene was transfected to cultured MSCs of Lewis rats using an adenoviral vector. Six million VEGF-transfected and LacZ-transfected MSCs (VEGF group), LacZ-transfected MSCs (control group), or serum-free medium only (medium group) were injected into syngeneic rat hearts 1 hour after left coronary artery occlusion. At 1 week after MI, MSCs were detected by X-gal staining in infarcted region. High expression of VEGF was immunostained in the VEGF group. At 28 days after MI, infarct size, left ventricular dimensions, ejection fraction, E wave/A wave ratio and capillary density of the infarcted region were most improved in the VEGF group, compared with the medium group. Immunohistochemically, ␣-smooth muscle actin-positive cells were most increased in the VEGF group. Key Words: angiogenesis Ⅲ gene therapy Ⅲ myocardial infarction Ⅲ stem cell Ⅲ transplantation C ell transplantation has become a promising novel therapy for ischemic heart disease and heart failure. Recent studies have revealed that various types of cells are effective in cell transplantation after myocardial infarction (MI), such as skeletal myoblasts, 1,2 smooth muscle cells, 3 and bone marrow mononuclear cells. 4 Bone marrow mononuclear cells are especially useful because they contain, among various lineage cells, hematopoietic cells and endothelial progenitor cells; therefore they have the ability to induce angiogenesis in ischemic tissue. A reported clinical trial of cell transplantation with skeletal myoblasts and mononuclear bone marrow cells showed that such therapies can have cardioprotective and angiogenic effects after MI. 5,6 However, selection of the most appropriate cell types for transplantation is controversial. Conclusions-ThisMesenchymal stem cells (MSCs) are isolated from bone marrow mononuclear cells and can be expanded ex vivo. Under appropriate culture conditions, MSCs have the potential to terminally differentiate into osteocytes, chondrocytes, adipocytes, tenocytes, myotubes, astrocytes, hematopoietic supporting stroma, and endothelial cells. 7 MSCs have also been used in a model of cell transplantation, 8,9 showing that these cells could differentiate into myogenic cells. Therefore, MSCs have many characteristics that make them useful for cellular therapy.Vascular endothelial growth factor (VEGF) is a strong therapeutic reagent for treating ischemia by inducing angiogenesis. 10 It has been reported that direct intramyocardial gene transfer results in localized enhancement of VEGF levels and successful angiogenesis in animal models of MI. 11 Furthermore, recent h...

Purpose: CD26 is a 110-kDa cell surface antigen with a role in tumor development. In this report, we show that CD26 is highly expressed on the cell surface of malignant mesothelioma and that a newly developed humanized anti-CD26 monoclonal antibody (mAb) has an inhibitory effect on malignant mesothelioma cells in both in vitro and in vivo experiments. Experimental Design: Using immunohistochemistry, 12 patients' surgical specimens consisting of seven malignant mesothelioma, three reactive mesothelial cells, and two adenomatoid tumors were evaluated for expression of CD26. The effects of CD26 on malignant mesothelioma cells were assessed in the presence of transfection of CD26-expressing plasmid, humanized anti-CD26 mAb, or small interfering RNA against CD26. The in vivo growth inhibitory effect of humanized anti-CD26 mAb was assessed in human malignant mesothelioma cell mouse xenograft models. Results: In surgical specimens, CD26 is highly expressed in malignant mesothelioma but not in benign mesothelial tissues. Depletion of CD26 by small interfering RNA results in the loss of adhesive property, suggesting that CD26 is a binding protein to the extracellular matrix. Moreover, our in vitro data indicate that humanized anti-CD26 mAb induces cell lysis of malignant mesothelioma cells via antibody-dependent cell-mediated cytotoxicity in addition to its direct anti-tumor effect via p27 kip1 accumulation. In vivo experiments with mouse xenograft models involving human malignant mesothelioma cells show that humanized anti-CD26 mAb treatment drastically inhibits tumor growth in tumor-bearing mice, resulting in enhanced survival. Conclusions: Our data strongly suggest that humanized anti-CD26 mAb treatment may have potential clinical use as a novel cancer therapeutic agent in CD26-positive malignant mesothelioma.

These data support the conclusion that heterozygous TGFBR2 mutations lead to decreased expression of SMC contractile protein in both SMCs and myofibroblasts. The failure of TGFBR2-mutant SMCs to fully express SMC contractile proteins predicts defective contractile function in these cells and aligns with a hypothesis that defective SMC contractile function contributes to the pathogenesis of TAAD.

Octamer binding transcription factors (Oct factors) play important roles in activation of transcription of various genes but, in some cases, require cofactors that interact with the DNA binding (POU) domain. In the present study, a yeast two-hybrid screen with the Oct-1 POU domain as a bait identified MAT1 as a POU domainbinding protein. MAT1 is known to be required for the assembly of cyclin-dependent kinase (CDK)-activating kinase (CAK), which is functionally associated with the general transcription factor IIH (TFIIH). Further analyses showed that MAT1 interacts with POU domains of Oct-1, Oct-2, and Oct-3 in vitro in a DNA-independent manner. MAT1-containing TFIIH was also shown to interact with POU domains of Oct-1 and Oct-2. MAT1 is shown to enhance the ability of a recombinant CDK7-cyclin H complex (bipartite CAK) to phosphorylate isolated POU domains, intact Oct-1, and the C-terminal domain of RNA polymerase II, but not the originally defined substrate, CDK2. Phosphopeptide mapping indicates that the site (Ser 385 ) of a mitosis-specific phosphorylation that inhibits Oct-1 binding to DNA is not phosphorylated by CAK. However, one CAK-phosphorylated phosphopeptide comigrates with a Cdc2-phosphorylated phosphopeptide previously shown to be mitosisspecific, suggesting that, in vitro, CAK is able to phosphorylate at least one site that is also phosphorylated in vivo. These results suggest (i) that interactions between POU domains and MAT1 can target CAK to Oct factors and result in their phosphorylation, (ii) that MAT1 not only functions as a CAK assembly factor but also acts to alter the spectrum of CAK substrates, and (iii) that a POU-MAT1 interaction may play a role in the recruitment of TFIIH to the preinitiation complex or in subsequent initiation and elongation reactions.

Purpose: CD26 is a 110-kDa cell surface glycoprotein with a role in tumor development through its association with key intracellular proteins. In this report, we show that binding of soluble anti-CD26 monoclonal antibody (mAb) inhibits the growth of the human renal carcinoma cells in both in vitro and in vivo experiments. Experimental Design: Growth inhibition by anti-CD26 mAb was assessed using proliferation assay and cell cycle analysis. Anti-CD26 mAb, chemical inhibitors, dominant-negative, or constitutively active forms of specific signaling molecules were used to evaluate CD26-associated pathways. The in vivo growth-inhibitory effect of anti-CD26 mAb was also assessed in a human renal carcinoma mouse xenograft model. Results:In vitro experiments show that anti-CD26 mAb induces G 1 -S cell cycle arrest associated with enhanced p27 kip1 expression, down-regulation of cyclin-dependent kinase 2, and dephosphorylation of retinoblastoma substrate. Moreover, our data show that enhanced p27 kip1 expression is dependent on the attenuation of Akt activity. Anti-CD26 mAb also internalizes cell surface CD26, leading to decreased binding to collagen and fibronectin. Experiments with a mouse xenograft model involving human renal carcinoma cells show that anti-CD26 mAb treatment drastically inhibits tumor growth in tumor-bearing mice, resulting in enhanced survival. Conclusions:Taken together, our data strongly suggest that anti-CD26 mAb treatment may have potential clinical use for CD26-positive renal cell carcinomas.

The aim of this study was to investigate the effect of chronic hypoxia on the development and progression of atherosclerosis in apolipoprotein E-knockout (apoE-KO) mice. Male and female apoE-KO mice (6 weeks old) and age-and sex-matched wild-type mice were kept under hypoxic conditions (10.0 ± 0.5% O2) in a gas chamber or in room air for 3 weeks. Aortic atherosclerotic plaque was not observed in wild-type mice under normoxic or hypoxic conditions. In the apoE-KO mice, however, hypoxia induced proliferation of smooth muscle cells and plaque formation in the aorta, which were not observed under normoxic conditions. Although sexual dimorphism of the response to hypoxia was not observed, these hypoxia-induced athero-