Cdon deficiency causes cardiac remodeling through hyperactivation of WNT/ß-catenin signaling.

On pathological stress, Wnt signaling is reactivated and induces genes associated with cardiac remodeling and fibrosis. We have previously shown that a cell surface receptor Cdon (cell-adhesion associated, oncogene regulated) suppresses Wnt signaling to promote neuronal differentiation however its role in heart is unknown. Here, we demonstrate a critical role of Cdon in cardiac function and remodeling. Cdon is expressed and predominantly localized at intercalated disk in both mouse and human hearts. Cdon-deficient mice develop cardiac dysfunction including reduced ejection fraction and ECG abnormalities. Cdon-/- hearts exhibit increased fibrosis and up-regulation of genes associated with cardiac remodeling and fibrosis. Electrical remodeling was demonstrated by up-regulation and mislocalization of the gap junction protein, Connexin 43 (Cx43) in Cdon-/- hearts. In agreement with altered Cx43 expression, functional analysis both using Cdon-/- cardiomyocytes and shRNA-mediated knockdown in rat cardiomyocytes shows aberrant gap junction activities. Analysis of the underlying mechanism reveals that Cdon-/- hearts exhibit hyperactive Wnt signaling as evident by ß-catenin accumulation and Axin2 up-regulation. On the other hand, the treatment of rat cardiomyocytes with a Wnt activator TWS119 reduces Cdon levels and aberrant Cx43 activities, similarly to Cdon-deficient cardiomyocytes, suggesting a negative feedback between Cdon and Wnt signaling. Finally, inhibition of Wnt/ß-catenin signaling by XAV939, IWP2 or dickkopf (DKK)1 prevented Cdon depletion-induced up-regulation of collagen 1a and Cx43. Taken together, these results demonstrate that Cdon deficiency causes hyperactive Wnt signaling leading to aberrant intercellular coupling and cardiac fibrosis. Cdon exhibits great potential as a target for the treatment of cardiac fibrosis and cardiomyopathy.

Neuromedin B receptor antagonism inhibits migration, invasion, and epithelial-mesenchymal transition of breast cancer cells.

Neuromedin B (NMB) acts as an autocrine growth factor and a pro-angiogenic factor. Its receptor, NMB receptor (NMB-R), is overexpressed in solid tumors. In the present study, we showed that an NMB-R antagonist, PD168368, suppresses migration and invasion of the human breast cancer cell line MDA-MB-231. In addition, PD168368 reduced epithelial-mesenchymal transition (EMT) of breast cancer cells by E-cadherin upregulation and vimentin downregulation. Moreover, we found that PD168368 potently inhibits in vivo metastasis of breast cancer. Taken together, these findings suggest that NMB-R antagonism may be an alternative approach to prevent breast cancer metastasis, and targeting NMB-R may provide a novel therapeutic strategy for breast cancer treatment.

Prmt7 Deficiency Causes Reduced Skeletal Muscle Oxidative Metabolism and Age-Related Obesity.

Maintenance of skeletal muscle function is critical for metabolic health and the disruption of which exacerbates many chronic diseases such as obesity and diabetes. Skeletal muscle responds to exercise or metabolic demands by a fiber-type switch regulated by signaling-transcription networks that remains to be fully defined. Here, we report that protein arginine methyltransferase 7 (Prmt7) is a key regulator for skeletal muscle oxidative metabolism. Prmt7 is expressed at the highest levels in skeletal muscle and decreased in skeletal muscles with age or obesity. Prmt7(-/-) muscles exhibit decreased oxidative metabolism with decreased expression of genes involved in muscle oxidative metabolism, including PGC-1α. Consistently, Prmt7(-/-) mice exhibited significantly reduced endurance exercise capacities. Furthermore, Prmt7(-/-) mice exhibit decreased energy expenditure, which might contribute to the exacerbated age-related obesity of Prmt7(-/-) mice. Similarly to Prmt7(-/-) muscles, Prmt7 depletion in myoblasts also reduces PGC-1α expression and PGC-1α-promoter driven reporter activities. Prmt7 regulates PGC-1α expression through interaction with and activation of p38 mitogen-activated protein kinase (p38MAPK), which in turn activates ATF2, an upstream transcriptional activator for PGC-1α. Taken together, Prmt7 is a novel regulator for muscle oxidative metabolism via activation of p38MAPK/ATF2/PGC-1α.

MRI Monitoring of Tumor-Selective Anticancer Drug Delivery with Stable Thermosensitive Liposomes Triggered by High-Intensity Focused Ultrasound.

Monitoring of drug release from a heat-activated liposome carrier provides an opportunity for real-time control of drug delivery and allows prediction of the therapeutic effect. We have developed short-chain elastin-like polypeptide-incorporating thermosensitive liposomes (STLs). Here, we report the development of STL encapsulating gadobenate dimeglumine (Gd-BOPTA), a MRI contrast agent, and doxorubicin (Dox) (Gd-Dox-STL). The Dox release profile from Gd-Dox-STL was comparable to Gd-Dox-LTSL; however, the serum stability of Gd-Dox-STL was much higher than Gd-Dox-LTSL. MRI studies showed that the difference in T1 relaxation time between 37 and 42 °C for Gd-Dox-STL was larger than the difference for Gd-Dox-LTSL. Although relaxivity for both liposomes at 42 °C was similar, the relaxivity of Gd-Dox-STL at 37 °C was 2.5-fold lower than that of Gd-Dox-LTSL. This was likely due to Gd-BOPTA leakage from the LTSL because of low stability at 37 °C. Pharmacokinetic studies showed plasma half-lives of 4.85 and 1.95 h for Gd-Dox-STL and Gd-Dox-LTSL, respectively, consistent with in vitro stability data. In vivo MRI experiments demonstrated corelease of Dox and Gd-BOPTA from STL under mild hyperthermia induced by high-intensity focused ultrasound (HIFU), which suggests STL is a promising tumor selective formulation when coupled with MR-guided HIFU.

Effects of Transplantation of CTLA4Ig-Overexpressing Adipose Tissue-Derived Mesenchymal Stem Cells in Mice With Sustained Severe Rheumatoid Arthritis.

CTLA4Ig has therapeutic potential for rheumatoid arthritis patients unresponsive to methotrexate (MTX) or TNF-α blockers. However, recombinant CTLA4Ig proteins are short acting and expensive. Adipose tissue-derived mesenchymal stem cells (ASCs) present an ideal stem cell source for practical regenerative medicine due to their abundant availability and their beneficial properties including immunomodulation, homing activity, paracrine effects, and differentiation ability. Therefore, we aimed to determine whether CTLA4Ig and human ASCs show synergistic effects on immunomodulation and clinical improvement of sustained severe rheumatoid arthritis in a mouse model. hASCs overexpressing CTLA4Ig (CTLA4Ig-hASC) were serially transplanted into mice with collagen-induced arthritis. Arthritic mice were subjected to four treatments based on their arthritis score on day 62 postimmunization: control (C group), hASC (H group), CTLA4Ig-hASC (CT group), and MTX (MTX group). A group of healthy mice was used as a normal control (N). Mice in the N and C groups were infused with 150 µl saline, and 2 × 10(6) hASCs or CTLA4Ig-hASCs in 150 µl of saline were intravenously administered to those in the H and CT groups, respectively, on days 63, 70, 77, and 84 after CII immunization. About 1 mg/kg of methotrexate was intraperitoneally administered to the MTX group three times a week for 4 weeks. Serial hASC and CTLA4Ig-hASC transplantation modulated various cytokines and chemokines related to the development of rheumatoid arthritis. Both treatments protected against destruction of cartilage, with CTLA4Ig-hASCs being most effective. Serum levels of CII autoantibodies and C-telopeptide of type II collagen were significantly low in the group transplanted with CTLA4Ig-hASCs. In vitro, ASC and CTLA4Ig-hASC treatment significantly decreased T-bet and GATA-3 expression in splenocytes from arthritic mice, and CTLA4Ig-hASC treatment significantly increased the ratio of Treg/Th17 (CD4(+)CD25(+)FoxP3(+)/CD4(+)CD25(+)RORγt) cells. Serial hASC and CTLA4Ig-hASC transplantation offers promising treatment for rheumatoid arthritis, and CTLA4Ig-hASCs showed stronger therapeutic effects than nontransduced hASCs.

Transplantation of Adipose Tissue-Derived Mesenchymal Stem Cells Prevents the Development of Lupus Dermatitis.

MRL/lpr mice spontaneously develop high titers of anti-dsDNA antibodies and symptoms such as glomerular nephritis and organ weight gain. They also develop spontaneous skin inflammation similar to the cutaneous lesions common in human lupus erythematosus. This study aimed to compare the effects of long-term serial administration of human adipose tissue-derived mesenchymal stem cells (ASCs), CTLA4Ig-overexpressing ASCs, and cyclophosphamide treatment in MRL/lpr mice. MRL/lpr mice were divided into saline (C), cyclophosphamide (Y), ASC early (E), ASC late (L), and CTLA4Ig-overexpressing ASC (CT) treatment groups. Background-matched control MRL/MPJ mice treated with saline (N) were also compared. The treatment period was 5-23 weeks, except for the L group (15-23 weeks). Blood and tissue samples were collected when the mice were 24 weeks old. Organ weight, anti-dsDNA antibodies, urine protein, skin and kidney histologic abnormalities, and trabecular bone volume were evaluated. The Y group showed the greatest decrease in anti-dsDNA antibodies, organ weight, degree of kidney inflammation and glomerular infiltration of C3, and incidence rate of severe proteinuria; the E, L, and CT treatment groups showed better results than the C group. ASC transplantation reduced anti-dsDNA antibody levels significantly. Mice treated with ASCs or CTLA4Ig-ASCs starting from the early disease stage did not show dermatitis upon gross examination; they demonstrated significant improvement in hyperkeratosis, acanthosis, and inflammatory cell infiltration scores in histopathology. Micro-CT analysis revealed that cyclophosphamide treatment significantly decreased bone volume and increased bone spacing in the trabecular bone. Thus, we found that ASC and CTLA4-ASC treatments prevent lupus dermatitis development in MRL/lpr mice without adverse effects.

Preventive effects of CTLA4Ig-overexpressing adipose tissue--derived mesenchymal stromal cells in rheumatoid arthritis.

BACKGROUND AIMS: Rheumatoid arthritis is a systemic autoimmune disorder. In this study, we first compared the therapeutic effects of syngeneic and xenogeneic adipose tissue-derived stem cells on a collagen-induced arthritis mouse model. Second, we investigated the synergistic preventive effects of CTLA4Ig and adipose tissue-derived mesenchymal stromal cells (ASCs) as a therapeutic substance. METHODS: Arthritis was induced in all groups except for the normal, saline (N) group, using chicken type II collagen (CII). Animals were divided into C (control, saline), H (hASCs), M (mASCs) and N groups (experiment I) and C, H, CT (CTLA4Ig-overexpressing human ASC [CTLA4Ig-hASCs]) and N groups (experiment II), according to transplanted material. Approximately 2 × 10(6) ASCs or 150 µL of saline was intravenously administered on days 24, 27, 30 and 34, and all animals were killed on days 42 to 44 after CII immunization. RESULTS: Anti-mouse CII autoantibodies were significantly lower in the H, M and CT groups than in the C group. Cartilage damage severity score and C-telopeptide of type II collagen were significantly lower in the CT group than in the C group. The serum levels of IL-6 were significantly lower in the H, M and CT groups than in the C group. The serum levels of keratinocyte chemoattractant were significantly lower in the CT group than the C group. CONCLUSIONS: There were similar effects of ASCs on the decrease of anti-mouse CII autoantibody levels between syngeneic and xenogeneic transplantations, and CTLA4Ig-hASCs showed synergistic preventive effects compared with non-transduced hASCs.

Cooperation of endothelial and smooth muscle cells derived from human induced pluripotent stem cells enhances neovascularization in dermal wounds.

Human induced pluripotent stem cells (hiPSCs) are generated through the reprogramming of somatic cells into an embryonic stem cell-like state, such that vascular cells differentiated from hiPSCs might be a suitable autologous cell source for vascular regeneration. The goal of this study was to assess whether cotransplantation of endothelial cells (ECs) and smooth muscle cells (SMCs) differentiated from hiPSCs could promote neovascularization and tissue repair in a murine dermal wound model. hiPSCs were differentiated into ECs and SMCs; the differentiated cells displayed cell-specific surface markers. Compared to primary somatic cells, ECs and SMCs, which were differentiated from hiPSCs, strongly cooperated to enhance in vitro tubular network formation. In vivo gel assays in athymic nude mice showed that the coimplantation of differentiated ECs and SMCs significantly increased vascularization, unlike that observed in the case of implantation of differentiated ECs alone. In a murine full-thickness wound model, when compared with the transplantation of primary somatic cells or phosphate-buffered saline, cotransplantation of differentiated ECs and SMCs markedly enhanced neovascularization in injured tissues and accelerated wound healing. These results demonstrate that cotransplantation of hiPSC-derived ECs and SMCs may be feasible as a new autologous cell therapy for neovascularization and tissue repair.

Novel temperature-triggered liposome with high stability: formulation, in vitro evaluation, and in vivo study combined with high-intensity focused ultrasound (HIFU).

We developed a novel temperature-sensitive liposome, STL composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-PEG-2000), cholesterol, and a fatty acid conjugated elastin-like polypeptide (ELP). The STL had a unilamellar spherical shape with a mean diameter of 160 nm. Doxorubicin (DOX) was encapsulated by the STL using an ammonium sulfate gradient method with a lipid to drug ratio of 1:0.2 (w/w), resulting in 95% loading efficiency. The STL exhibited better stability than conventional low temperature sensitive liposome (LTSL-lysolipid-based temperature sensitive liposomes; DPPC:MSPC:DSPE-PEG-2000=90:10:4) at 37 °C in the presence of serum; there was rapid release of doxorubicin in the range of 39-42 °C (≥95% release at 42 °C within 10s). A confocal microscope revealed that DOX encapsulated in STL (STL-DOX) was taken up much better by cell nuclei at 42 °C than at 37 °C. The difference in cell viability between 37 and 42 °C was 63% relative to STL-DOX and 18% for LTSL-DOX. The pharmacokinetics (PK) and antitumor effect of STL-DOX combined with high-intensity focused ultrasound (HIFU) were studied, and compared with LTSL. An in vivo study demonstrated that STL-DOX is highly stable, with a long circulating property (half life=2.03±0.77 h) in HIFU-untreated mice, and resulted in significant tumor regression for 2 days after intravenous injection of STL-DOX at 5 mg DOX/kg in combination with HIFU. These results are better than conventional LTSL, for which the blood circulation time is short (0.92±0.17 h) and inhibition of tumor growth is weak. These results indicate that the properties of stability at 37 °C and burst release at 42 °C of STL-DOX act synergistically against tumors.

Cyclin-dependent kinase 4 signaling acts as a molecular switch between syngenic differentiation and neural transdifferentiation in human mesenchymal stem cells.

Multipotent mesenchymal stem/stromal cells (MSCs) are capable of differentiating into a variety of cell types from different germ layers. However, the molecular and biochemical mechanisms underlying the transdifferentiation of MSCs into specific cell types still need to be elucidated. In this study, we unexpectedly found that treatment of human adipose- and bone marrow-derived MSCs with cyclin-dependent kinase (CDK) inhibitor, in particular CDK4 inhibitor, selectively led to transdifferentiation into neural cells with a high frequency. Specifically, targeted inhibition of CDK4 expression using recombinant adenovial shRNA induced the neural transdifferentiation of human MSCs. However, the inhibition of CDK4 activity attenuated the syngenic differentiation of human adipose-derived MSCs. Importantly, the forced regulation of CDK4 activity showed reciprocal reversibility between neural differentiation and dedifferentiation of human MSCs. Together, these results provide novel molecular evidence underlying the neural transdifferentiation of human MSCs; in addition, CDK4 signaling appears to act as a molecular switch from syngenic differentiation to neural transdifferentiation of human MSCs.

Pulsed high-intensity focused ultrasound therapy enhances targeted delivery of cetuximab to colon cancer xenograft model in mice.

Our aim was to evaluate whether pulsed high-intensity focused ultrasound (HIFU) therapy enhances the effect of an epidermal growth factor receptor-targeted chemotherapeutic drug, cetuximab, in treating human colon cancer xenografts in a mouse model. Balb/c nude mice with subcutaneous xenografts of HT-29 cells were randomly categorized into control (n = 9), pulsed HIFU alone (n = 10), cetuximab monotherapy (n = 8) or combined pulsed HIFU and cetuximab therapy (n = 9) group. Cetuximab, pulsed HIFU therapy, or both were administered three times per week starting from day 8 after tumor cell injection. Based on tumor growth curves up to 34 days, the combination therapy group showed more suppressed tumor growth than all other groups (p < 0.05). The final relative tumor volumes were 5.4 ± 2.1, 5.2 ± 1.3, 4.8 ± 1.8, and 3.1 ± 0.9 for control, pulsed HIFU alone, cetuximab monotherapy, and combination therapy groups, respectively. In conclusion, pulsed HIFU therapy appears to enhance the anti-tumor effect of epidermal growth factor receptor-targeted cetuximab on human colon cancer xenograft models in mice.

Synthesis and cellular uptake of scatteredly cyclic RGDfK-conjugated superparamagnetic iron oxide nanoparticles.

We prepared scatteredly cyclic RGDfK-conjugated water-dispersible superparamagnetic iron oxide nanoparticles (cRGDfK-WSPIONs) and investigated their cellular uptake to MS-1 cells (mouse endothelial cell lines, express integrin α(v)ß(3)) and MCF-7 cells (human breast cancer cells, express low level of integrin α(v)ß(3)) using in vitro MRI. The cRGDfK-WSPIONs were prepared from oleate-protected SPIONs (SPION-OA) as follows. Some oleates (OAs) on the SPION-OA were substituted by mercaptohexadecanoic acids (MHA) and cRGDfKs were conjugated to MHAs. Finally, the remaining OAs were substituted by mercaptopropionic acids without detaching preexisting cRGDfK-conjugated MHA ligands from the SPION surface. The cRGDfK-WSPIONs showed drastically higher cellular uptake than its corresponding control WSPIONs to MS-1 cells and also, showed higher selectivity to MS-1 cells than to MCF-7 cells, both implicating integrin α(v)ß(3)-mediated cellular uptake of scatteredly cRGDfK-conjugated WSPIONs.

Gas-filled phospholipid nanoparticles conjugated with gadolinium play a role as a potential theragnostics for MR-guided HIFU ablation.

To develop a long-circulating theragnostics, meaning therapeutics and diagnostics for MR-guided HIFU ablation, we designed and prepared Gd-C(5)F(12)-phospholipid nanobubbles (PLNs) 30-100 nm in diameter. The biochemical and physical characterization of Gd-C(5)F(12)-PLNs were performed. Since Gd-C(5)F(12)-PLN-50 (Φ = 50 nm) and Gd-C(5)F(12)-PLN-100 (Φ = 100 nm) enhanced the hyperthermal effect of HIFU size- and concentration-dependently in a tissue-mimicking phantom, its circulation, distribution, tumor accumulation and tumor ablation were examined in tumor-bearing mice. The plasma-half life of Gd-C(5)F(12)-PLNs was longer than 1.5 hrs. Gd-C(5)F(12)-PLNs mainly accumulated in the liver and the spleen, suggesting that they are slowly secreted through the hepatobiliary pathway. Monitored by the T1 signal intensity of MR, Gd-C(5)F(12)-PLNs accumulated in tumor tissues for 8 hours in mice. HIFU with Gd-C(5)F(12)-PLN-100 showed the increased tumor ablation area as compared with HIFU alone. The results suggest that Gd-C(5)F(12)-PLNs exhibit a potential theragnostics for MR-guided HIFU ablation.

Sonophoresis using ultrasound contrast agents for transdermal drug delivery: an in vivo experimental study.

Sonophoresis temporally increases skin permeability such that various medications can be delivered noninvasively. Previous sonophoresis studies have suggested that cavitation plays an important role in enhancing transdermal drug delivery (TDD). In this study, the feasibility of controlled cavitation using ultrasound contrast agents (UCAs) at high frequency was explored through in vivo experiments in a rat model. Two commercially available UCAs, SonoVue® and Definity®, were used at 2.47 MHz and 1.12 MHz, respectively. Fluorescein isothiocyanate (FITC)-dextran with 0.1% UCA was used as the drug to be delivered through the skin. Ultrasound with a 10 ms pulse and a 1% duty cycle at 1 MPa acoustic pressure for 30 min was applied in all sonication sessions. The efficacy of sonophoresis with UCAs was quantitatively analyzed using an optical imaging system that was used to count photons emitted from fluorescein. The results showed that the proposed sonophoresis method significantly improved drug penetration compared with the traditional sonophoresis method with 4 kD, 20 kD and 150 kD FITC-dextrans at 1.12 MHz, and with 4 kD and 20 kD FITC-dextrans at 2.47 MHz. Sonophoresis for TDD was performed more effectively with the aid of UCAs. Sonophoresis with UCAs has excellent potential for broad applications in drug delivery for diseases requiring the chronic administration of medications such as diabetes.

Neuromedin B receptor antagonist suppresses tumor angiogenesis and tumor growth in vitro and in vivo.

Neuromedin B (NMB), a member of the mammalian bombesin-like peptide family, and its receptor were aberrantly expressed in vascularized solid tumors. Here, the NMB receptor (NMB-R) antagonist PD168368 specifically inhibited both NMB-induced in vivo and in vitro angiogenesis. In addition, PD168368 showed growth inhibitory effects on MDA-MB-231 breast cancer cells by inducing cell cycle arrest and apoptosis. Furthermore, PD168368 effectively suppressed tumor growth in a xenograft model of breast tumor in vivo. Overall, NMB-R antagonist exhibited a significant antitumor activity by simultaneously inhibiting neovascularization and cancer cell growth, thereby suggesting that NMB-R could be a potential therapeutic target for cancer treatment.

COMP-angiopoietin-1 decreases lipopolysaccharide-induced acute kidney injury.

During sepsis endothelial dysfunction is an important pathogenetic mechanism in acute kidney injury (AKI). Lipopolysaccharide (LPS)-induced endotoxemia is associated with renal hemodynamic changes such as alterations of renal blood flow (RBF), vascular resistance, and glomerular filtration rate. We used adenoviral delivery of an engineered variant of native angiopoietin-1 (COMP-angiopoietin-1) containing anti-inflammatory and anti-permeability functions, to determine if regulation of renal endothelial cell dysfunction may have a beneficial role in preventing AKI during LPS-induced endotoxemia in mice. This treatment prevented the endotoxin-induced decrease of RBF and mean arterial pressure while improving glomerular filtration rate. Treatment also mitigated the effects of LPS on renal intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 protein expression, the number of ER-HR3-positive macrophages that infiltrated the kidney, serum nitrate/nitrite levels, renal inducible nitric oxide synthase protein expression, the induction of tubular epithelial reactive oxygen and nitrogen species, and renal microvascular permeability. Our findings show that COMP-angiopoietin-1, an endothelium-oriented therapeutic agent, protects against AKI caused by endotoxemia.

Molecular MR imaging for visualizing ICAM-1 expression in the inflamed synovium of collagen-induced arthritic mice.

OBJECTIVE: To determine the utility of intercellular adhesion molecule (ICAM)-1 antibody-conjugated gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA-anti-ICAM-1) as a targeted contrast agent for the molecular magnetic resonance imaging (MRI) in collagen-induced arthritis (CIA). MATERIALS AND METHODS: THREE GROUPS OF MICE WERE USED: non-arthritic normal, CIA mice in both the early inflammatory and chronic destructive phases. The MR images of knee joints were obtained before and after injection of Gd-DTPA-anti-ICAM-1, Gd-DTPA, and Gd-DTPA-Immunoglobulin G (Ig G) and were analyzed quantitatively. The patterns of enhancement on the MR images were compared with the histological and immunohistochemical ICAM-1 staining. RESULTS: The images obtained after injection of Gd-DTPA-anti-ICAM-1 displayed gradually increasing signal enhancement from the moment following injection (mean +/- standard deviation [SD]: 424.3 +/- 35.2, n = 3) to 24 hours (532 +/- 11.3), rather than on pre-enhanced images (293 +/- 37.6) in the early inflammatory phase of CIA mice. However, signal enhancement by Gd-DTPA and Gd-DTPA-IgG disappeared after 80 minutes and 24 hours, respectively. In addition, no significant enhancement was seen in the chronic destructive phase of CIA mice, even though they also showed inflammatory changes on T2-weighted MR images. ICAM-1 expression was demonstrated in the endothelium and proliferating synovium of the early inflammatory phase of CIA mice, but not in the chronic destructive phase. CONCLUSION: Molecular MRI with Gd-DTPA-anti-ICAM-1 displays specific images targeted to ICAM-1 that is expressed in the inflamed synovium of CIA. This novel tool may be useful for the early diagnosis and differentiation of the various stages of rheumatoid arthritis.

Endothelial progenitor cell homing: prominent role of the IGF2-IGF2R-PLCbeta2 axis.

Homing of endothelial progenitor cells (EPCs) to the neovascular zone is now considered to be an essential step in the formation of vascular networks during embryonic development and also for neovascularization in postnatal life. We report here the prominent role of the insulin-like growth factor 2 (IGF2)/IGF2 receptor (IGF2R) system in promoting EPC homing. With high-level expression of IGF2R in EPCs, IGF2-induced hypoxic conditions stimulated multiple steps of EPC homing in vitro and promoted both EPC recruitment and incorporation into the neovascular area, resulting in enhanced angiogenesis in vivo. Remarkably, all IGF2 actions were exerted predominantly through IGF2R-linked G(i) protein signaling and required intracellular Ca(2+) mobilization induced by the beta2 isoform of phospholipase C. Together, these findings indicate that locally generated IGF2 at either ischemic or tumor sites may contribute to postnatal vasculogenesis by augmenting the recruitment of EPCs. The utilization of the IGF2/IGF2R system may therefore be useful for the development of novel means to treat angiogenesis-dependent diseases.

Visfatin enhances ICAM-1 and VCAM-1 expression through ROS-dependent NF-kappaB activation in endothelial cells.

Visfatin has recently been identified as a novel visceral adipokine which may be involved in obesity-related vascular disorders. However, it is not known whether visfatin directly contributes to endothelial dysfunction. Here, we investigated the effect of visfatin on vascular inflammation, a key step in a variety of vascular diseases. Visfatin induced leukocyte adhesion to endothelial cells and the aortic endothelium by induction of the cell adhesion molecules, ICAM-1 and VCAM-1. Promoter analysis revealed that visfatin-mediated induction of CAMs is mainly regulated by nuclear factor-kappaB (NF-kappaB). Visfatin stimulated IkappaBalpha phosphorylation, nuclear translocation of the p65 subunit of NF-kappaB, and NF-kappaB DNA binding activity in HMECs. Furthermore, visfatin increased ROS generation, and visfatin-induced CAMs expression and NF-kappaB activation were abrogated in the presence of the direct scavenger of ROS. Taken together, our results demonstrate that visfatin is a vascular inflammatory molecule that increases expression of the inflammatory CAMs, ICAM-1 and VCAM-1, through ROS-dependent NF-kappaB activation in endothelial cells.

Colloidal gold nanoparticles as a blood-pool contrast agent for X-ray computed tomography in mice.

OBJECTIVES: To present the pharmacokinetics and computed tomographic imaging efficacy of colloidal gold nanoparticles (AuNPs) as a blood-pool agent for x-ray computed tomography (CT). METHODS AND MATERIALS: To prepare the colloidal AuNPs, gold nanocrystals were modified using sulfhydrated polyethylene glycol (PEG). Cytotoxicity and histopathologic tests were carried out for toxicity evaluation. Six adult Balb/c mice underwent microcomputed tomography scans after injection of colloidal AuNPs (2.5 micromol Au/g body weight). Four mice with HT-1080 tumors were imaged for visualization of the tumor vasculature. RESULTS: The PEG coated colloidal AuNPs appeared as spherical nanoparticles with 38-nm diameters. The AuNPs-PEG showed a biocompatibility without toxicity in the mice. We identified a stable imaging window for visualizing the vasculature system, immediately to 24 hours after injection. Microcomputed tomography imaging using AuNPs-PEG clearly visualized the tumor vascular structures. CONCLUSION: Colloidal AuNPs show potential as a blood-pool agent for x-ray CT imaging.