Abstract-We investigated whether the mobilization of endothelial progenitor cells (EPCs) by exogenous erythropoietin (Epo) promotes the repair of injured endothelium. Recombinant human Epo was injected (1000 IU/kg for the initial 3 days) after wire injury of the femoral artery of mice. Neointimal formation was inhibited by Epo to 48% of the control (PϽ0.05) in an NO-dependent manner. Epo induced a 1.4-fold increase in reendothelialized area of day 14 denuded vessels, 55% of which was derived from bone marrow (BM) cells. Epo increased the circulating Sca-1 ϩ /Flk-1 ϩ EPCs (2.0-fold, PϽ0.05) with endothelial properties NO dependently. BM replacement by GFP-or ␤-galactosidaseoverexpressing cells showed that Epo stimulated both differentiation of BM-derived EPCs and proliferation of resident ECs. BM-derived ECs increased 2.2-to 2.7-fold (PϽ0.05) in the Epo-induced neoendothelium, where the expression of Epo receptor was upregulated. Epo induced Akt/eNOS phosphorylation and NO synthesis on EPCs and exerted an antiapoptotic action on wire-injured arteries. In conclusion, Epo treatment inhibits the neointimal hyperplasia after arterial injury in an NO-dependent manner by acting on the injured vessels and mobilizing EPCs to the neo-endothelium.

A new series of high-performance fluorophores named Keio Fluors (KFL), which are based on borondipyrromethene (BODIPY), are reported. The KFL dyes cover a wide spectral range from the yellow (547 nm) to the near-infrared (NIR, 738 nm) region, and their emission wavelength could be easily and subtly controlled based on simple molecular modifications only, without losing their optical properties. This "tailor-made" synthetic strategy for tuning the emission wavelength enabled the creation of fourteen KFL dyes with well-controlled emission colors (yellow, orange, red, far-red, and NIR). Moreover, these KFL dyes also retain their excellent optical properties, such as spectral bands sharper than quantum dots, high extinction coefficients (140,000-316,000 M(-1) cm(-1)), and high quantum yields (0.56-0.98), without any critical solvent polarity dependent decrease of their brightness. These advantageous characteristics make the KFL dyes potentially useful as new candidates of fluorescent standard dyes to substitute or to complement existing long-wavelength fluorescent dyes, such as cyanines, oxazines, rhodamines, or other BODIPY dyes.

Rationale: It has been reported that interleukin (IL)-1 is associated with pathological cardiac remodeling and LV dilatation, whereas IL-1␤ has also been shown to induce cardiomyocyte hypertrophy. Thus, the role of IL-1 in the heart remains to be determined. Objective: We studied the role of hypertrophy signal-mediated IL-1␤/insulin-like growth factor (IGF)-1 production in regulating the progression from compensative pressure-mediated hypertrophy to heart failure. Methods and Results: Pressure overload was performed by aortic banding in IL-1␤-deficient mice. Primarily cultured cardiac fibroblasts (CFs) and cardiac myocytes (CMs) were exposed to cyclic stretch. Heart weight, myocyte size, and left ventricular ejection fraction were significantly lower in IL-1␤-deficient mice (20%, 23% and 27%, respectively) than in the wild type 30 days after aortic banding, whereas interstitial fibrosis was markedly augmented. DNA microarray analysis revealed that IGF-1 mRNA level was markedly (Ϸ50%) decreased in the IL-1␤-deficient hypertrophied heart. Stretch of CFs, rather than CMs, abundantly induced the generation of IL-1␤ and IGF-1, whereas such IGF-1 induction was markedly decreased in IL-1␤-deficient CFs. IL-1␤ released by stretch is at a low level unable to induce IL-6 but sufficient to stimulate IGF-1 production. Promoter analysis showed that stretch-mediated IL-1␤ activates JAK/STAT to transcriptionally regulate the IGF-1 gene. IL-1␤ deficiency markedly increased c-Jun N-terminal kinase (JNK) and caspase-3 activities and enhanced myocyte apoptosis and fibrosis, whereas replacement of IGF-1 or JNK inhibitor restored them. Conclusions: We demonstrate for the first time that pressure-mediated hypertrophy and mechanical stretch generates a subinflammatory low level of IL-1␤, which constitutively causes IGF-1 production to maintain adaptable compensation hypertrophy and inhibit interstitial fibrosis. (Circ Res. 2009;105:1149-1158.)Key Words: interleukin-1 Ⅲ insulin-like growth factor-1 Ⅲ Akt Ⅲ JNK Ⅲ hypertrophy C ardiac hypertrophy is defined by augmentation of the ventricular mass against hemodynamic loads and upregulates contractile capacity and reduces ventricular wall stress, 1 whereas the capacity of this compensation is limited, and stronger and longer pressure overload induces pathological cardiac remodeling with left ventricular (LV) dilatation. 1 Pathological cardiac remodeling is associated with production of the extracellular matrix and causes increased signals of myocyte apoptosis. 2 Receptor tyrosine kinase, such as insulin-like growth factor (IGF)-1 receptor is involved in not only physiological hypertrophy 3 but also compensated hypertrophy after pressure overload. 4 IGF-1 promotes myocardial hypertrophy by activating phosphatidylinositol 3-kinase (PI3K) and its downstream effector Akt. 5,6 In addition, mitogenactivated protein kinase 7 acts as downstream molecules to promote hypertrophy.Overexpression of G protein-coupled 7-transmembrane receptors in the heart induced cardiac remodeling, resulting in he...

Ketone bodies including b-hydroxybutyrate (b-OHB) have been shown to protect against ischemic tissue injury when present at low concentrations. We evaluated the impact of b-OHB on renal ischemia/reperfusion injury (IRI). Mice were treated with a continuous infusion of b-OHB using an osmotic mini-pump before and after IRI. We also tested the effects of increasing endogenous serum b-OHB levels by fasting. Renal IRI was attenuated by b-OHB treatment compared to saline control, with similar results in the fasting condition. b-OHB treatment reduced the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells and increased expression of forkhead transcription factor O3 (FOXO3), an upstream regulator of pyroptosis. Although b-OHB treatment did not impact markers of apoptosis, it decreased the expression of caspase-1 and proinflammatory cytokines, indicating that b-OHB blocked pyroptosis. In a human proximal tubular cell line exposed to hypoxia and reoxygenation, b-OHB reduced cell death in a FOXO3-dependent fashion. Histone acetylation was decreased in kidneys exposed to IRI and in proximal tubular cells exposed to hypoxia and reoxygenation, and this effect was ameliorated by b-OHB through the inactivation of histone deacetylases. In vitro, b-OHB treatment restored histone acetylation at the FOXO3 promoter. Consistent with epigenetic molecular effects, the renoprotective effects of b-OHB were still observed when the continuous infusion was stopped at the time of IRI. Thus, b-OHB attenuates renal IRI through anti-pyroptotic effects, likely mediated by an epigenetic effect on FOXO3 expression.

Background-The involvement of Ca 2ϩ -dependent tyrosine kinase PYK2 in the Akt/endothelial NO synthase pathway remains to be determined. Methods and Results-Blood flow recovery and neovessel formation after hind-limb ischemia were impaired in PYK2

Background-The angiotensin II (Ang II) type 1 (AT 1 ) receptor is expressed in bone marrow (BM) cells, whereas it remains poorly defined how Ang II regulates differentiation/proliferation of monocyte-lineage cells to exert proatherogenic actions. Methods and Results-We generated BM chimeric apoE Ϫ/Ϫ mice repopulated with AT 1 -deficient (Agtr1 Key Words: bone marrow progenitors Ⅲ angiotensin Ⅲ monocyte Ⅲ atherosclerosis Ⅲ M-CSF T he angiotensin II (Ang II) type 1 (AT 1 ) receptor exerts proatherogenic actions. 1 AT 1 receptor-deficient (Agtr1 Ϫ/Ϫ ) mice showed a significant reduction of atherosclerotic development, 2,3 and treatment with AT 1 receptor blocker (ARB) reduced the size of atherosclerotic lesions both in experimental animals and humans. 4 AT 1 receptors are present in a variety of cells, including endothelial cells, vascular smooth muscle cells, and bone marrow (BM) stem cells and progenitors. 5,6 Recently, Cassis et al demonstrated that Ang II-induced atherosclerosis was significantly attenuated in LDL receptor-deficient (LDLr Ϫ/Ϫ ) mice whose BM cells were repopulated with Agtr1 Ϫ/Ϫ cells. 7 Fukuda et al also reported that atherosclerotic lesion development was significantly reduced in apoE-deficient (apoE Ϫ/Ϫ ) mice with Agtr1 Ϫ/Ϫ marrow. 8 However, no information regarding the role of the BM-AT 1 receptor on the differentiation/proliferation and properties of BM stem cells and progenitors has been reported in these previous studies.Monocytes and macrophages play a crucial role in the pathogenesis of atherosclerosis, which is characterized by plaque progression, destabilization, and subsequent plaque rupture, through foam cell formation, migration/proliferation of resident vascular smooth muscle cells, and degradation of extracellular matrix. 9 Along with the previous studies showing the effect of diet-induced hypercholesterolemia on BM and leukocyte, 10 Swirski et al reported that hypercholesterolemia induced a surprisingly profound expansion of blood monocytes as well as BM monocyte-lineage cells. 11 However, the relative contribution of the BM renin-angiotensin system to hypercholesterolemia-associated monocytosis has not been fully investigated. 12 In the present study, we focused on the action of the AT 1 receptor expressed in BM cells and studied whether (1) Ang II affects the differentiation/proliferation from BM stem cells into monocyte-lineage cells, and (2) MethodsA full description of all methods can be found in the Data Supplement (available online at http://atvb.ahajournals.org). Animal PreparationApoE Ϫ/Ϫ mice (C57BL/6) and AT1a receptor-deficient (Agtr1 Ϫ/Ϫ ) mice (C57BL/6) were obtained from Taconic Co Ltd (Germantown, NY) and Tanabe Seiyaku Co Ltd (Osaka, Japan), respectively. BM cells of 2-month-old female apoE Ϫ/Ϫ recipient mice were repopulated with male Agtr1 Ϫ/Ϫ or Agtr1 ϩ/ϩ cells. The percentage chimerism determined by transplanting GFP-overexpressing BM cells was 96Ϯ2% of peripheral blood mononuclear cells. 13 Furthermore, BM CD45 Ϫ CD34 Ϫ stromal cells, HSCs, and myeloid ...

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We report a novel near-infrared fluorescent calcium probe (KFCA), which has good optical properties such as intense NIR fluorescence emission (670 nm, QY: 0.24), excellent ON/OFF ratio (120-fold), and good wavelength-compatibility with visible-light-emissive fluorophores (Fluo-4, DsRed2), and which is applicable for real-time dual-colour intracellular Ca(2+) imaging.