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DNA and proteins fold in three dimensions (3D) to enable functions that sustain life. Emulation of such folding schemes for functional materials can unleash enormous potential in advancing a wide range of technologies, especially in robotics, medicine, and telecommunication. Here, we report a microfolding strategy that enables formation of 3D morphable microelectronic systems integrated with various functional materials, including monocrystalline silicon, metallic nanomembranes, and polymers. By predesigning folding hosts and configuring folding pathways, 3D microelectronic systems in freestanding forms can transform across various complex configurations with modulated functionalities. Nearly all transitional states of 3D microelectronic systems achieved via the microfolding assembly can be easily accessed and modulated in situ, offering functional versatility and adaptability. Advanced morphable microelectronic systems including a reconfigurable microantenna for customizable telecommunication, a 3D vibration sensor for hand-tremor monitoring, and a bloomable robot for cardiac mapping demonstrate broad utility of these assembly schemes to realize advanced functionalities.

Background Myeloid cells play an important role in a wide variety of cardiovascular disorders, including both ischemic and non-ischemic cardiomyopathies. Neuregulin-1 (NRG-1)/ErbB signaling has recently emerged as an important factor contributing to the control of inflammatory activation of myeloid cells after an ischemic injury. However, the role of ErbB signaling in myeloid cells in non-ischemic cardiomyopathy is not fully understood. This study investigated the role of ErbB3 receptors in the regulation of early adaptive response using a mouse model of transverse aortic constriction (TAC) for non-ischemic cardiomyopathy. Methods and results TAC surgery was performed in groups of age- and sex-matched myeloid cell-specific ErbB3-deficient mice (ErbB3MyeKO) and control animals (ErbB3MyeWT). The number of cardiac CD45 immune cells, CD11b myeloid cells, Ly6G neutrophils, and Ly6C monocytes was determined using flow cytometric analysis. Five days after TAC, survival was dramatically reduced in male but not female ErbB3MyeKO mice or control animals. The examination of lung weight to body weight ratio suggested that acute pulmonary edema was present in ErbB3MyeKO male mice after TAC. To determine the cellular and molecular mechanisms involved in the increased mortality in ErbB3MyeKO male mice, cardiac cell populations were examined at day 3 post-TAC using flow cytometry. Myeloid cells accumulated in control but not in ErbB3MyeKO male mouse hearts. This was accompanied by increased proliferation of Sca-1 positive non-immune cells (endothelial cells and fibroblasts) in control but not ErbB3MyeKO male mice. No significant differences in intramyocardial accumulation of myeloid cells or proliferation of Sca-1 cells were found between the groups of ErbB3MyeKO and ErbB3MyeWT female mice. An antibody-based protein array analysis revealed that IGF-1 expression was significantly downregulated only in ErbB3MyeKO mice hearts compared to control animals after TAC. Conclusion Our data demonstrate the crucial role of myeloid cell-specific ErbB3 signaling in the cardiac accumulation of myeloid cells, which contributes to the activation of cardiac endothelial cells and fibroblasts and development of an early adaptive response to cardiac pressure overload in male mice.

Herein, we employed lead-free Cs3Cu2I5 perovskite films as the functional layers to construct Al/Cs3Cu2I5/ITO memory devices and systematically investigated the impact on the corresponding resistive switching (RS) performance via adding different amounts of hydroiodic acid (HI) in Cs3Cu2I5 precursor solution. The results demonstrated that the crystallinity and morphology of the Cs3Cu2I5 films can be improved and the resistive switching performance can be modulated by adding an appropriate amount of HI. The obtained Cs3Cu2I5 films by adding 5 μL HI exhibit the fewest lattice defects and flattest surface (RMS = 13.3 nm). Besides, the memory device, utilizing the optimized films, has a low electroforming voltage (1.44 V), a large on/off ratio (∼65), and a long retention time (104 s). The RS performance impacted by adding HI, providing a scientific strategy for improving the RS performance of iodine halide perovskite-based memories.

Background: Cardiac fibroblasts (CFs) have a central role in the ventricular remodeling process associated with different types of fibrosis. Recent studies have shown that fibroblasts do not respond homogeneously to heart injury. Because of the limited set of bona fide fibroblast markers, a proper characterization of fibroblast population heterogeneity in response to cardiac damage is lacking. The purpose of this study was to define CF heterogeneity during ventricular remodeling and the underlying mechanisms that regulate CF function. Methods: Collagen1α1–GFP (green fluorescent protein)–positive CFs were characterized after myocardial infarction (MI) by single-cell and bulk RNA sequencing, assay for transposase-accessible chromatin sequencing, and functional assays. Swine and patient samples were studied using bulk RNA sequencing. Results: We identified and characterized a unique CF subpopulation that emerges after MI in mice. These activated fibroblasts exhibit a clear profibrotic signature, express high levels of Cthrc1 (collagen triple helix repeat containing 1), and localize into the scar. Noncanonical transforming growth factor–β signaling and different transcription factors including SOX9 are important regulators mediating their response to cardiac injury. Absence of CTHRC1 results in pronounced lethality attributable to ventricular rupture. A population of CFs with a similar transcriptome was identified in a swine model of MI and in heart tissue from patients with MI and dilated cardiomyopathy. Conclusions: We report CF heterogeneity and their dynamics during the course of MI and redefine the CFs that respond to cardiac injury and participate in myocardial remodeling. Our study identifies CTHRC1 as a novel regulator of the healing scar process and a target for future translational studies.

There has been extensive interest in cellular therapies for the treatment of myocardial infarction, but bottlenecks concerning cellular accumulation and retention remain. Here, a novel system of in situ crosslinking mesenchymal stem cells (MSCs) for the formation of a living depot at the infarct site is reported. Bone marrow-derived mesenchymal stem cells that are surface decorated with heterodimerizing leucine zippers, termed ZipperCells, are engineered. When delivered intravenously in sequential doses, it is demonstrated that ZipperCells can migrate to the infarct site, crosslink, and show ≈500% enhanced accumulation and ≈600% improvement in prolonged retention at 10 days after injection compared to unmodified MSCs. This study introduces an advanced approach to creating noninvasive therapeutics depots using cellular crosslinking and provides the framework for future scaffold-free delivery methods for cardiac repair.

Background Pure cypress forests experience problems such as reductions in biodiversity, lowered capabilities for water and soil conservation, decreased underground productivity and land degradation. To improve the conditions of pure forests, we studied the effects of mixed gaps on the cypress (Cupressus funebris) pure forest, selecting the Chinese toon (Toona sinensis), which is a deciduous broad-leaved tree, as the mixed tree species. We examined the variations in the concentrations of C, N, and P and their ratios in plant tissues, litter and soils in different seasons in pure cypress forests with 4 different sizes of mixed gaps (50, 100, 150, 200 m2). Results The leaf N:P ratios of cypress and Chinese toon were 10.77 and 12.74, respectively, and N was the main limiting factor for tree growth in the study area. The N and P resorption rates of the cypress pure forest were 57.4% and 60.7%, respectively, and mixed gaps with Chinese toon increased the resorption rates. An analysis of correlations among leaf-litter-soil stoichiometry indicated that the correlations between the soil nutrient elements and the corresponding plant leaves and litter increased when the broadleaf tree species was introduced into the cypress pure forest. Conclusions These results indicate that the introduction of broad-leaved species was favorable for triggering the forest soil nutrient recycling process.

Mutations in TGF-β-activated kinase 1 binding protein 2 (TAB2) have been implicated in the pathogenesis of dilated cardiomyopathy and/or congenital heart disease in humans, but the underlying mechanisms are currently unknown. Here, we identified an indispensable role for TAB2 in regulating myocardial homeostasis and remodeling by suppressing receptor-interacting protein kinase 1 (RIPK1) activation and RIPK1-dependent apoptosis and necroptosis. Cardiomyocyte-specific deletion of Tab2 in mice triggered dilated cardiomyopathy with massive apoptotic and necroptotic cell death. Moreover, Tab2-deficient mice were also predisposed to myocardial injury and adverse remodeling after pathological stress. In cardiomyocytes, deletion of TAB2 but not its close homolog TAB3 promoted TNF-α-induced apoptosis and necroptosis, which was rescued by forced activation of TAK1 or inhibition of RIPK1 kinase activity. Mechanistically, TAB2 critically mediates RIPK1 phosphorylation at Ser321 via a TAK1-dependent mechanism, which prevents RIPK1 kinase activation and the formation of RIPK1-FADD-caspase-8 apoptotic complex or RIPK1-RIPK3 necroptotic complex. Strikingly, genetic inactivation of RIPK1 with Ripk1-K45A knockin effectively rescued cardiac remodeling and dysfunction in Tab2-deficient mice. Together, these data demonstrated that TAB2 is a key regulator of myocardial homeostasis and remodeling by suppressing RIPK1-dependent apoptosis and necroptosis. Our results also suggest that targeting RIPK1-mediated cell death signaling may represent a promising therapeutic strategy for TAB2 deficiency-induced dilated cardiomyopathy.

Thinning can significantly promote forest productivity and ecological function. Rhizosphere fungi play an indispensable role in regulating nutrient cycling between plants and the environment, and their community composition can positively respond to anthropogenic disturbance. However, the initial effects of thinning on rhizosphere fungal community assembly have seldom been reported. In this research, we studied the alterations in the rhizosphere fungal communities of 29-year-old Pinus massoniana in East Sichuan 2 years after three different thinning intensity treatments. In addition, the responses of fungal community and functional group composition to alterations in understory vegetation and soil physiochemical properties were analyzed. Three thinning intensities were set, which were 0 (CK), 25% (LIT), and 50% (HIT), respectively. The results suggested that the richness index and Shannon index of understory vegetation increased significantly with increasing thinning intensity. The alpha diversity indices of rhizosphere fungal community and soil physiochemical properties did not show significant differences among the three treatments. The relative abundances of 17 fungal indicator species varied regularly with increasing thinning intensity, and most of them belong to Hypocreales and Eurotiales, indicating that these two orders were potential indicators for different thinning treatments. Rhizosphere fungal community assembly was determined by deterministic process, and it was driven by the diversity of understory vegetation in the initial stage of thinning. The Simpson index and Pielou index of herbs were useful measures of the main environmental factors driving the differentiation of fungal functional group composition. Based on network analysis, thinning resulted in distinct co-occurrence patterns of rhizosphere fungal functional groups. This research elucidates the initial role of thinning in rhizosphere fungal community assembly of P. massoniana and has practical significance for the functional restoration and protection of local forest ecosystem.

Introduction: Understanding molecular mechanisms underlying cardiac hypertrophy is crucial for protecting against cardiac remodeling, or slowing down its destined pathway to heart failure. Recent studies revealed that myeloid cells play an important role in the regulation of hypertrophic remodeling. Neuregulin-1 (NRG-1) has been shown to play an essential role in the regulation of tissue-protective and pro-survival processes in response to tissue injury in the cardiovascular system. We find that NRG-1 receptors, including ErbB2 and ErbB3, are expressed and functionally active in cardiac myeloid cells. We hypothesized that the NRG-1/ErbB3 signaling in myeloid cells plays a protective role in cardiac hypertrophic remodeling. To test this hypothesis, we examined the effect of Erbb3 gene ablation in mouse myeloid cells on cardiac hypertrophic remodeling induced by pressure overload. Methods and results: Myeloid-specific ErbB3-deficient mice (ErbB3 MyeKO ) were generated by crossing Erbb3 -floxed mice with LysM-Cre transgenic mice. Cardiac hypertrophic remodeling was established in mice by transverse aortic constriction (TAC). Five days after TAC, survival was dramatically reduced in male ErbB3 MyeKO mice (20% vs. 90%, p=0.021 , MyeKO vs. MyeWT). The post-mortem examination of lung weight to body weight ratio suggested that acute pulmonary edema was developed in ERBB3 MyeKO mice. In order to determine the cellular and molecular mechanisms involved in the increased mortality in ErbB3 MyeKO males, cardiac cell populations were examined at day 3 post-TAC using flow cytometry. A significant accumulation of myeloid cells was found in control but not in ErbB3 MyeKO males. This was accompanied by increased proliferation of Sca-1 positive non-immune cells (endothelial cells and cardiac progenitors) in control but not ErbB3 MyeKO males. An antibody-based protein array analysis revealed that IGF-1 expression was significantly downregulated only in ErbB3 MyeKO males after TAC. Conclusion: Our data highlight the important role of myeloid cell-specific ErbB3 signaling in the accumulation of myeloid cells that contributes to the development of compensatory hypertrophy and the prevention of acute heart failure in male mice.

Previous studies have found that pure even harmonics are generated from oriented CO molecules in linearly polarized laser fields. In this work, we demonstrate multi-directions pure even harmonic simultaneous generation from planar molecules in linearly polarized laser fields using the time-dependent density-functional theory. The analysis reveals that pure even harmonic generation depends on the special symmetry of the planar molecule. In the linearly polarized laser field, it is found that only when the planar molecules have reflective symmetry direction and the molecules perpendicular to the reflective symmetry direction do not have reflection symmetry can the planar molecules generate pure even harmonics along such reflective symmetry direction. When the laser polarization is perpendicular to the planar molecule, if the molecule has several these directions of such reflection symmetry, pure even harmonics will be simultaneously generated along these symmetrical directions. Moreover, when the laser polarization is along the molecular plane and perpendicular to the direction of one such reflection symmetry, even harmonic is also generated along this reflection symmetry direction, whereas odd harmonic is generated along the direction of laser polarization. The phenomenon exists in all polyatomic planar molecules with such reflection symmetry.

Background: Programmed cell death, including apoptosis, mitochondria-mediated necrosis, and necroptosis, is critically involved in ischemic cardiac injury, pathological cardiac remodeling, and heart failure progression. Whereas apoptosis and mitochondria-mediated necrosis signaling is well established, the regulatory mechanisms of necroptosis and its significance in the pathogenesis of heart failure remain elusive. Methods: We examined the role of tumor necrosis factor receptor-associated factor 2 (Traf2) in regulating myocardial necroptosis and remodeling using genetic mouse models. We also performed molecular and cellular biology studies to elucidate the mechanisms by which Traf2 regulates necroptosis signaling. Results: We identified a critical role for Traf2 in myocardial survival and homeostasis by suppressing necroptosis. Cardiac-specific deletion of Traf2 in mice triggered necroptotic cardiac cell death, pathological remodeling, and heart failure. Plasma tumor necrosis factor α level was significantly elevated in Traf2 -deficient mice, and genetic ablation of TNFR1 largely abrogated pathological cardiac remodeling and dysfunction associated with Traf2 deletion. Mechanistically, Traf2 critically regulates receptor-interacting proteins 1 and 3 and mixed lineage kinase domain-like protein necroptotic signaling with the adaptor protein tumor necrosis factor receptor-associated protein with death domain as an upstream regulator and transforming growth factor β-activated kinase 1 as a downstream effector. It is important to note that genetic deletion of RIP3 largely rescued the cardiac phenotype triggered by Traf2 deletion, validating a critical role of necroptosis in regulating pathological remodeling and heart failure propensity. Conclusions: These results identify an important Traf2-mediated, NFκB-independent, prosurvival pathway in the heart by suppressing necroptotic signaling, which may serve as a new therapeutic target for pathological remodeling and heart failure.

Numerous findings demonstrate that there is a strong association between maternal health during pregnancy and cardiovascular disease in adult offspring. The purpose of the present study was to test whether maternal gestational hypertension modulates brain renin–angiotensin–aldosterone system (RAAS) and proinflammatory cytokines that sensitizes angiotensin II–elicited hypertensive response in adult offspring. In addition, the role of renal nerves and the RAAS in the sensitization process was investigated. Reverse transcription polymerase chain reaction analyses of structures of the lamina terminalis and paraventricular nucleus indicated upregulation of mRNA expression of several RAAS components and proinflammatory cytokines in 10-week-old male offspring of hypertensive dams. Most of these increases were significantly inhibited by either renal denervation performed at 8 weeks of age or treatment with an angiotensin-converting enzyme inhibitor, captopril, in drinking water starting at weaning. When tested beginning at 10 weeks of age, a pressor dose of angiotensin II resulted in enhanced upregulation of mRNA expression of RAAS components and proinflammatory cytokines in the lamina terminalis and paraventricular nucleus and an augmented pressor response in male offspring of hypertensive dams. The augmented blood pressure change and most of the increases in gene expression in the offspring were abolished by either renal denervation or captopril. The results suggest that maternal hypertension during pregnancy enhances pressor responses to angiotensin II through overactivity of renal nerves and the RAAS in male offspring and that upregulation of the brain RAAS and proinflammatory cytokines in these offspring may contribute to maternal gestational hypertension-induced sensitization of the hypertensive response to angiotensin II.

Objective: Necroptosis is a new caspase-independent, regulated form of necrosis, which has recently been implicated in ischemic cardiac injury and remodeling. This study aims to determine a novel ubiquitination-dependent mechanism that regulates necroptosis in the heart and the implications of necroptosis signaling in the setting of ischemic injury and remodeling. Methods and Results: Here we identified a novel ubiquitination-dependent mechanism mediated by the E3 ubiquitin ligase TRAF2 (TNF receptor associated factor-2) and the deubiquitinase CYLD (cylindromatosis), which critically regulates myocardial necroptosis and pathological remodeling. TRAF2 and CYLD specifically regulate K63-linked protein ubiquitination, which regulates signal transduction but not proteasomal degradation. Intriguingly, CYLD is up-regulated, but TRAF2 is down-regulated, in the heart after ischemia-reperfusion injury. We found that wild-type TRAF2 inhibits, whereas the ligase inactive mutant TRAF2-ΔRING promotes cardiomyocyte necroptosis. Importantly, acute deletion of TRAF2 in the adult heart in Traf2 fl/fl -MerCreMer mice induces severe dilated cardiomyopathy and lethal heart failure by promoting myocardial necroptosis. Conversely, AAV9-mediated TRAF2 gene transfer significantly attenuates ischemic-reperfusion injury. On the other hand, CYLD overexpression promotes, whereas CYLD deletion inhibits cardiomyocyte necroptosis. In vivo , genetic ablation of CYLD in Cyld-/- mice attenuates ischemic myocardial injury and adverse remodeling by suppressing myocardial necroptosis. Mechanistically, TRAF2 and CYLD opposingly regulate K63-linked polyubiquitination of TAK1 (TGFβ-activated kinase 1), TAK1-RIP1 interaction, and the formation of RIP1-RIP3 necrosome. These results thus identify a ubiquitination-dependent mechanism of necroptosis mediated by TRAF2 and CYLD, providing a new paradigm of necroptosis signaling. Conclusion: The E3 ligase TRAF2 and the deubiquitinase CYLD, as a suppressor and an activator of necroptosis respectively, opposingly regulate myocardial homeostasis, ischemic injury, and remodeling, thus representing promising therapeutic targets for heart disease.

Introduction: The human adult heart contains a subset of mesenchymal cells characterized by high proliferative potential and capability to differentiate into different cell types. We recently demonstrated that a high level of ErbB2 expression is associated with differentiation of human highly proliferative cells (hHiPC) into endothelial cells in vitro. Based on our findings, we hypothesized that ErbB2 high hHiPC play a critical role in early revascularization and repair of injured heart. To test this hypothesis, we performed xenotransplantation of human ERBB2 high hHiPC into mouse hearts and analyzed the phenotype of transplanted cells and cardiac function on day 7 after experimental myocardial infarction (MI). Methods: The effect of ErbB2 high hHiPC was tested in immunodeficient NSG mice. MI was induced by permanent ligation of the left coronary artery. Human ERBB2 high hHiPC (2.5 x 10 5 cells) were injected into the peri-infarct zone immediately after MI. Echocardiography was performed on unsedated mice before and on days 7 after MI. Examination of transplantation efficiency and hHiPC phenotype was performed using flow cytometric analysis of cell suspension obtained from left ventricles (LV). Results: We found that up to 25% of cardiac endothelial cells were represented by cells that originated from hHiPC, as identified by specific expression of human CD31, in mouse LV, on day 7 after MI. The total number of cells expressing mouse or human endothelial cell markers, CD31 and CD105, within non-immune cardiac cell population was higher in mice that received injection of hHiPC compared to control mice (PBS injection) (4.7 vs. 2.9 x 10 5 cells, hHiPC vs. PBS, p= 0.026 ). Echocardiographic analysis revealed that mice which received an injection of ERBB2 high cells demonstrated significantly improved cardiac function compared to control mice injected with PBS (fractional shortening: 21.6% vs. 15.3% for hHiPC vs. PBS, p=0.023 ). Conclusion: ERBB2 high hHiPC survive, undergo endothelial cell differentiation in vivo, and contribute to the pool of cardiac endothelial cells after experimental myocardial infarction. A population of ErbB2 high hHiPC obtained from adult human hearts can be used to improve the revascularization of injured myocardium or other tissues.

Cardiac fibroblasts have a central role during the ventricular remodeling process associated with different types of cardiac injury. Recent studies have shown that fibroblasts do not respond homogeneously to heart damage, suggesting that the adult myocardium may contain specialized fibroblast subgroups with specific functions. Due to the limited set of bona fide fibroblast markers, a proper characterization of fibroblast population dynamics in response to cardiac damage is still missing. Using single-cell RNA-seq, we identified and characterized a fibroblast subpopulation that emerges in response to myocardial infarction (MI) in a murine model. These activated fibroblasts exhibit a clear pro-fibrotic signature, express high levels of the hormone CTHRC1 and of the immunomodulatory co-receptor CD200 and localize to the injured myocardium. Combining epigenomic profiling with functional assays, we show Sox9 and the non-canonical TGF-β signaling as important regulators mediating their response to cardiac damage. We show that the absence of CTHRC1, in this activated fibroblast subpopulation, results in pronounced lethality due to ventricular rupture in a mouse model of myocardial infarction. Finally, we find evidence for the existence of similar mechanisms in a pig pre-clinical model of MI and establish a correlation between CTHRC1 levels and cardiac function after MI.

© 2016 The Author. Aims Impaired Ca2+cycling and myocyte contractility are a hallmark of heart failure triggered by pathological stress such as hemodynamic overload. The A-Kinase anchoring protein AKAP150 has been shown to coordinate key aspects of adrenergic regulation of Ca2+cycling and excitation-contraction in cardiomyocytes. However, the role of the AKAP150 signalling complexes in the pathogenesis of heart failure has not been investigated. Methods and results Here we examined how AKAP150 signalling complexes impact Ca2+cycling, myocyte contractility, and heart failure susceptibility following pathological stress. We detected a significant reduction of AKAP150 expression in the failing mouse heart induced by pressure overload. Importantly, cardiac-specific AKAP150 knockout mice were predisposed to develop dilated cardiomyopathy with severe cardiac dysfunction and fibrosis after pressure overload. Loss of AKAP150 also promoted pathological remodelling and heart failure progression following myocardial infarction. However, ablation of AKAP150 did not affect calcineurin-nuclear factor of activated T cells signalling in cardiomyocytes or pressure overload-or agonist-induced cardiac hypertrophy. Immunoprecipitation studies showed that AKAP150 was associated with SERCA2, phospholamban, and ryanodine receptor-2, providing a targeted control of sarcoplasmic reticulum Ca2+regulatory proteins. Mechanistically, loss of AKAP150 led to impaired Ca2+cycling and reduced myocyte contractility reserve following adrenergic stimulation or pressure overload. Conclusions These findings define a critical role for AKAP150 in regulating Ca2+cycling and myocardial ionotropy following pathological stress, suggesting the AKAP150 signalling pathway may serve as a novel therapeutic target for heart failure.

Municipal solid waste incineration (MSWI) fly ash is a by-product of garbage incineration power generation, and its disposal is currently a world problem because it contains over standard heavy metals. This research aims to solidify the heavy metals in MSWI fly ash and make it to be utilizable construction materials under the guidance of intermediate-calcium cementitious materials (ICCM), and meanwhile figure out the solidification and hydration mechanism. The hydration characteristics of ICCM were characterized by XRD, FTIR, 29Si MAS-NMR and SEM techniques, and the environmental properties are investigated by TCLP and EPMA. The results indicate that the optimal ratio of (CaO + MgO)/(SiO2 + Al2O3) for ICCM is at the range of 0.76–0.88. The compressive strengths of ICCM reach the 42.5R normal Portland cement level, and the leaching concentrations of heavy metals meet the Chinese integrated wastewater discharge standard GB 8978-1996. As predominant hydration products, ettringite, hydrocalumite and amorphous C-S-H gel are principally responsible for the strength development of ICCM, and the (Ca + Mg)/(Si + Al) ratio at 0.88 has the best polymerized structure. The heavy metals are well solidified through combining with the C-S-H gel or absorbed in the hydration pastes. This paper provides an effective solution to use the MSWI fly ash in building material.

Programed cell death, including apoptosis and necroptosis, is critically involved in ischemic cardiac injury, pathological cardiac remodeling, and heart failure progression. Whereas apoptosis signaling is well established, the regulatory mechanisms of necroptosis and its significance in the pathogenesis of heart failure remain largely unkown. Here we identified TNF receptor-associated factor 2 (Traf2) as a key suppressor of myocardial necroptosis, which critically regulates myocardial survival and homeostasis. It has been shown that transgenic expression of Traf2 protects the heart against ischemia-reperfusion injury, but the underlying mechanisms remain unclear. Moreover, the role of Traf2 in myocardial necroptosis and pathological remodeling has not been investigated in a loss-of-function approach. By generating cardiac-specific Traf2 knockout mice, we found that ablation of Traf2 in the heart induced pathological remodeling and heart failure by promoting necroptotic myocyte death. Importantly, plasma TNFα level was significantly elevated in Traf2 -deficient mice, and genetic ablation of TNFR1 (TNF receptor-1) largely abrogated pathological cardiac remodeling and dysfunction associated with Traf2 deficiency. Mechanistically, our data revealed that Traf2 critically regulates RIP1-RIP3-MLKL necroptosis signaling, with the adaptor protein TRADD (TNFR1-associated death domain protein) as an upstream regulator and TAK1 (TGFβ-activated kinase-1) as a downstream effector. Moreover, Traf2 prevents the degradation of key pro-survival signaling proteins TAK1, FLIP, cIAPs, and NFκB-p65 via the ubiquitin-proteasome pathway. Lastly, genetic deletion of RIP3 largely rescued the cardiac phenotype triggered by Traf2 deletion, further validating a critical role of necroptosis in regulating pathological remodeling and heart failure propensity. Taken together, these results identify an important Traf2-mediated, NFκB-independent, pro-survival pathway in the heart by suppressing necroptosis signaling, which may serve as a new therapeutic target for pathological remodeling and heart failure.

Our recent study identified a key role for TAK1 (transforming growth factor β activated kinase-1) in regulating myocardial remodeling and heart failure propensity by antagonizing necroptosis, also termed programmed necrosis ( Circulation 2014;130:2162-2172). TAB2 (TAK1 binding protein-2) is an adaptor protein that regulates TAK1 activation and downstream signaling. Here we tested the hypothesis that TAB2 functions as a critical regulator of myocardial necroptosis and pathological remodeling. We found that both TAB2 and TAK1 were up-regulated during compensatory cardiac hypertrophy but down-regulated in end-stage heart failure. Genetic ablation of TAB2 in cardiomyocytes, but not other TAK1 binding proteins TAB1 or TAB2, markedly increased necroptosis in response to TNFα stimulation. Genetic deletion of RIP3 (receptor interacting protein-3), a key regulator of necroptosis, also largely blocked cell death in TAB2-deficent cells, further confirming the role of TAB2 in regulating necroptotic cell death. Mechanistically, our data showed that TAB2 functions as a molecular switch that tightly regulates TAK1-RIP1 interaction (pro-survival) and the RIP1-RIP3 necrosome formation (pro-necroptosis). We further showed that loss of TAB2 promotes necroptosis in cardiomyocytes via two independent mechanisms: acutely through the induction of RIP1-RIP3 necrosome and later through inhibition of the NFκB pathway. Importantly, cardiac-specific ablation of TAB2 in mice showed enhanced pathological remodeling with massive fibrosis and necroptosis, and the TAB2-deficient mice gradually developed dilated cardiomyopathy and heart failure starting 2 months old. Moreover, the TAB2-deficient mice are also predisposed to heart failure after pathological stress by pressure overload or myocardial infarction, suggesting a protective role of TAB2 in cardiac stress response. These results strongly indicate that TAB2 functions as a molecular switch that critically regulates the pro-survival TAK1 signaling and the necroptosis machinery, thus playing a critical role in myocardial survival and stress response. The TAB2-TAK1 signaling network may serve as a novel therapeutic target in heart disease and other pathological conditions driven by necroptosis.

Faithful progression through the cell cycle is crucial to the maintenance and developmental potential of stem cells. Here, we demonstrate that neural stem cells (NSCs) and intermediate neural progenitor cells (NPCs) employ a zinc-finger transcription factor specificity protein 2 (Sp2) as a cell cycle regulator in two temporally and spatially distinct progenitor domains. Differential conditional deletion of Sp2 in early embryonic cerebral cortical progenitors, and perinatal olfactory bulb progenitors disrupted transitions through G1, G2 and M phases, whereas DNA synthesis appeared intact. Cell-autonomous function of Sp2 was identified by deletion of Sp2 using mosaic analysis with double markers, which clearly established that conditional Sp2-null NSCs and NPCs are M phase arrested in vivo. Importantly, conditional deletion of Sp2 led to a decline in the generation of NPCs and neurons in the developing and postnatal brains. Our findings implicate Sp2-dependent mechanisms as novel regulators of cell cycle progression, the absence of which disrupts neurogenesis in the embryonic and postnatal brain.

Impaired Ca 2+ cycling and myocyte contractility are a hallmark of heart failure triggered by pathological stress such as hemodynamic overload. The A-Kinase anchoring protein AKAP150 has been shown to coordinate key aspects of adrenergic regulation of Ca 2+ cycling and excitation-contraction in cardiomyocytes. However, the role of the AKAP150 signaling complexes in the pathogenesis of heart failure is largely unknown. Here we investigate how AKAP150 signaling complexes impact Ca 2+ cycling, myocyte contractility, and heart failure susceptibility following pathological stress. We detected a significant reduction of AKAP150 expression in the failing mouse heart induced by pressure overload. Importantly, cardiac-specific AKAP150 knockout mice were predisposed to develop dilated cardiomyopathy with severe cardiac dysfunction and fibrosis after pressure overload. Loss of AKAP150 also promoted pathological remodeling and heart failure progression following myocardial infarction. However, ablation of AKAP150 did not appear to affect chronic activation of calcineurin-NFAT signaling in cardiomyocytes or pressure overload- or agonist- induced cardiac hypertrophy. Immunoprecipitation studies showed that AKAP150 was associated with SERCA2, phospholamban, and ryanodine receptor-2, providing a targeted control of sarcoplasmic reticulum Ca 2+ regulatory proteins. Mechanistically, loss of AKAP150 led to impaired Ca 2+ cycling and reduced myocyte contractility reserve following adrenergic stimulation or pressure overload. These findings define a critical role for AKAP150 in maintaining Ca 2+ homeostasis and myocardial ionotropy following pathological stress, suggesting the AKAP150 signaling pathway may serve as a novel therapeutic target for heart failure.

Necroptosis has emerged as a new form of programmed cell death implicated in a number of pathological conditions such as ischemic injury, neurodegenerative disease, and viral infection. Recent studies indicate that TGFβ-activated kinase 1 (TAK1) is nodal regulator of necroptotic cell death, but the underlying molecular regulatory mechanisms remain elusive. Here we reported that TAK1 regulates necroptotic signaling as well as caspase 8 activation through both NFκB-dependent and -independent mechanisms. Inhibition of TAK1 promoted TNFα-induced necroptosis through the induction of RIP1 phosphorylation/activation and necrosome formation, in the presence of ongoing caspase activation. Further, inhibition of TAK1 triggered two caspase 8 activation pathways through the induction of RIP1-FADD-caspase 8 complex as well as FLIP cleavage/degradation. Mechanistically, our data uncovered an essential role of the adaptor protein TRADD in caspase 8 activation and necrosome formation triggered by TAK1 inhibition. Moreover, ablation of the deubiqutinase CYLD prevented both apoptotic and necroptotic signaling induced by TAK1 inhibition, whereas deletion of the E3 ubiquitin ligase TRAF2 had the opposite effect. Finally, blocking the ubiquitin-proteasome pathway prevented the degradation of key necroptotic signaling proteins and necrosome formation. Thus we identified novel regulatory mechanisms underling the critical role of TAK1 in necroptotic signaling through regulation of multiple cell death checkpoints. Targeting key components of the necroptotic pathway (e.g., TRADD and CYLD) and the ubiquitin-proteasome pathway may represent novel therapeutic strategies for pathological conditions driven by necroptosis.

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure(1). A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function(2). Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

The Sp family of transcription factors is required for the expression of cell cycle- and developmentally regulated genes, and the deregulated expression of a handful of family members is associated with human tumorigenesis. Sp2 is a relatively poorly characterized member of the Sp family that, although widely expressed, exhibits little or no DNA binding or transcriptional activity in human and mouse cell lines. To begin to address the role(s) played by Sp2 in early metazoan development we have cloned and characterized Sp2 from zebrafish (Danio rerio). We report that 1) the intron/exon organization and amino acid sequence of zebrafish Sp2 is closely conserved with its mammalian orthologues, 2) zebrafish Sp2 weakly stimulates an Sp-dependent promoter in vitro and associates with the nuclear matrix in a DNA-independent fashion, 3) zebrafish Sp2 is inherited as a maternal transcript, is transcribed in zebrafish embryos and adult tissues, and is required for completion of gastrulation, and 4) zebrafish lines carrying transgenes regulated by the Sp2 promoter recapitulate patterns of endogenous Sp2 expression.

TAK1 (TGFβ-activated kinase-1) signaling is essential in regulating a number of important biological functions, including innate immunity, inflammatory response, cell growth and differentiation and myocardial homeostasis. The precise role of TAK1 in the adult heart under pathological conditions remains largely unknown. Importantly, we observed that TAK1 is upregulated during compensatory hypertrophy but downregulated in end-stage heart failure. Here we generated transgenic mice with inducible expression of an active TAK1 mutant (TAK1ΔN) in the adult heart. TAK1ΔN transgenic mice developed greater cardiac hypertrophy compared with control mice after transverse aortic constriction (TAC), which was largely blocked by ablation of calcineurin Aβ. Expression of TAK1ΔN also promoted NFAT (nuclear factor of activated T-cells) transcriptional activity in luciferase reporter mice at baseline, which was further enhanced after TAC. Our results revealed that activation of TAK1 promoted adaptive cardiac hypertrophy through a cross-talk between calcineurin-NFAT and IKK-NFκB pathways. More significantly, adult-onset inducible expression of TAK1ΔN protected the myocardium from adverse remodeling and heart failure after myocardial infarction or long-term pressure overload, by preventing cardiac cell death and fibrosis. Mechanistically, TAK1 exerts its cardioprotective effect through activation of NFAT/NFκB, downregulation of Bnip3 and inhibition of cardiac cell death.

We have reported that extracts prepared from many human and mouse cell lines show little or no Sp2 DNA-binding activity and that Sp2 has little or no capacity to stimulate transcription of promoters that are activated by Sp1, Sp3, and Sp4. Using an array of chimeric Sp1/Sp2 proteins we showed further that Sp2 DNA-binding activity and trans-activation are each negatively regulated in mammalian cells. As part of an ongoing effort to study Sp2 function and regulation we characterized its subcellular localization in comparison with other Sp-family members in fixed and live cells. We report that 1) Sp2 localizes largely within subnuclear foci associated with the nuclear matrix, and 2) these foci are distinct from promyelocytic oncogenic domains and appear to be stable during an 18-h time course of observation. Deletion analyses identified a 37 amino acid sequence spanning the first zinc-“finger” that is sufficient to direct nuclear matrix association, and this region also encodes a bipartite nuclear localization sequence. A second nuclear matrix targeting sequence is encoded within the Sp2 trans-activation domain. We conclude that Sp2 preferentially associates with the nuclear matrix and speculate that this subcellular localization plays an important role in the regulation of Sp2 function.

The synthesis of 11 oligosaccharides (4-14) containing beta-arabinofuranosyl residues is reported. The glycans are all fragments of two polysaccharides, arabinogalactan and lipoarabinomannan, which are found in the cell wall complex of mycobacteria. In the preparation of the targets, the key step was a low-temperature glycosylation reaction that installed the beta-arabinofuranosyl residues with good to excellent stereocontrol.

The synthesis of oligosaccharides containing arabinofuranose residues is reported. Coupling of thioglycoside donors 4 , 6 , or 7 and with acceptors 8 – 17 using N -iodosuccinimide and silver triflate activation provided glycosides with varying degrees of stereocontrol.

Necroptosis has emerged as a new form of programmed cell death implicated in a number of pathological conditions such as ischemic injury, neurodegenerative disease, and viral infection. Recent studies indicate that TGFβ-activated kinase 1 (TAK1) is nodal regulator of necroptotic cell death, although the underlying molecular regulatory mechanisms are not well defined. Here we reported that TAK1 regulates necroptotic signaling as well as caspase 8-mediated apoptotic signaling through both NFκB-dependent and -independent mechanisms. Inhibition of TAK1 promoted TNFα-induced cell death through the induction of RIP1 phosphorylation/activation and necrosome formation. Further, inhibition of TAK1 triggered two caspase 8 activation pathways through the induction of RIP1-FADD-caspase 8 complex as well as FLIP cleavage/degradation. Mechanistically, our data uncovered an essential role for the adaptor protein TNF receptor-associated protein with death domain (TRADD) in caspase 8 activation and necrosome formation triggered by TAK1 inhibition. Moreover, ablation of the deubiqutinase CYLD prevented both apoptotic and necroptotic signaling induced by TAK1 inhibition. Finally, blocking the ubiquitin-proteasome pathway prevented the degradation of key pro-survival signaling proteins and necrosome formation. Thus, we identified new regulatory mechanisms underlying the critical role of TAK1 in cell survival through regulation of multiple cell death checkpoints. Targeting key components of the necroptotic pathway (e.g., TRADD and CYLD) and the ubiquitin-proteasome pathway may represent novel therapeutic strategies for pathological conditions driven by necroptosis.

The synthesis of oligosaccharides containing arabinofuranose residues is reported. Coupling of thioglycoside donors 4 , 6 , or 7 and with acceptors 8 – 17 using N -iodosuccinimide and silver triflate activation provided glycosides with varying degrees of stereocontrol.