Self-assembly of tetravalent Goldberg polyhedra from 144 small components.

Rational control of the self-assembly of large structures is one of the key challenges in chemistry, and is believed to become increasingly difficult and ultimately impossible as the number of components involved increases. So far, it has not been possible to design a self-assembled discrete molecule made up of more than 100 components. Such molecules-for example, spherical virus capsids-are prevalent in nature, which suggests that the difficulty in designing these very large self-assembled molecules is due to a lack of understanding of the underlying design principles. For example, the targeted assembly of a series of large spherical structures containing up to 30 palladium ions coordinated by up to 60 bent organic ligands was achieved by considering their topologies. Here we report the self-assembly of a spherical structure that also contains 30 palladium ions and 60 bent ligands, but belongs to a shape family that has not previously been observed experimentally. The new structure consists of a combination of 8 triangles and 24 squares, and has the symmetry of a tetravalent Goldberg polyhedron. Platonic and Archimedean solids have previously been prepared through self-assembly, as have trivalent Goldberg polyhedra, which occur naturally in the form of virus capsids and fullerenes. But tetravalent Goldberg polyhedra have not previously been reported at the molecular level, although their topologies have been predicted using graph theory. We use graph theory to predict the self-assembly of even larger tetravalent Goldberg polyhedra, which should be more stable, enabling another member of this polyhedron family to be assembled from 144 components: 48 palladium ions and 96 bent ligands.

An Organometallic Strategy for Assembling Atomically Precise Hybrid Nanomaterials.

For decades, chemists have strived to mimic the intricate design and diverse functions of naturally occurring systems through the bioinspired synthesis of programmable inorganic nanomaterials. The development of thiol-capped gold nanoparticles (AuNPs) has driven advancement in this area; however, although versatile and readily accessible, hybrid AuNPs are rarely atomically precise, which limits control over their surface topology and therefore the study of complex structure-function relationships. Here, we present a bottom-up approach to the systematic assembly of atomically precise hybrid nanoclusters employing a strategy that mimics the synthetic ease with which thiol-capped AuNPs are normally constructed, while producing well-defined covalent nanoscale assemblies with diverse surface topologies. For the first time, using a structurally characterized cluster-based organometallic building block, we demonstrate the systematic synthesis of nanoclusters with multivalent binding capabilities to complex protein targets.

Histone methylation and demethylation are implicated in the transient and sustained activation of the interleukin-1ß gene in murine macrophages.

Macrophages play a crucial role in the development of atherosclerosis. To explore the mechanism by which macrophages attain a proinflammatory phenotype for a sustained period, we stimulated macrophages with lipopolysaccharide (LPS) and interferon-γ (IFN-γ) and measured the interleukin-1ß (IL-1ß) expression. The IL-1ß expression increased transiently, and its expression lasted for, at least, 1 week after the cessation of LPS and IFN-γ stimulation. At the promoter region of the IL-1ß gene, the demethylation of histone H3 lysine 27 (H3K27) was significantly induced for 1 week after transient stimulation with LPS and IFN-γ. The expression of H3K27 demethylases ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX) and jumonji domain-containing 3 (JMJD3) increased significantly for 1 week after transient stimulation with LPS and IFN-γ. When the UTX expression was inhibited by using small interfering RNA (siRNA) for UTX, the IL-1ß expression was significantly suppressed in both transient and sustained phases, whereas siRNA for JMJD3 significantly inhibited only the sustained phase of the IL-1ß expression. These results suggested that H3K27 demethylation was implicated in the transient and sustained increase in the IL-1ß expression after LPS and IFN-γ stimulation.

Endogenous Interleukin-1ß Is Implicated in Intraplaque Hemorrhage in Apolipoprotein E Gene Null Mice.

BACKGROUND: Intraplaque hemorrhage (IPH) has been implicated in plaque instability and rupture in atherosclerotic lesions, although the mechanisms by which IPH progresses remain largely unknown. In this study, apolipoprotein E-deficient mice with carotid artery ligation and cuff placement around the artery were used, and pro-inflammatory cytokines that are implicated in IPH were analyzed.Methods and Results:The expression of interleukin-1ß (IL-1ß) increased significantly following cuff placement compared with mice with carotid artery ligation alone. IPH occurred in the cuff-placed carotid artery following treatment with the negative control (NC) small interfering RNA (siRNA). However, the occurrence was significantly reduced in the cuff-placed carotid artery following treatment with an IL-1ß siRNA. Neovessel formation was significantly reduced in the carotid artery treated with the NC siRNA compared with that treated with IL-1ß siRNA. IL-1ß significantly inhibited the tube formation and wound healing capacities of vascular endothelial cells in vitro. Furthermore, immunostaining of matrix metalloproteinase-9 (MMP-9) significantly increased in the carotid artery treated with the NC siRNA compared with that treated with IL-1ß siRNA. CONCLUSIONS: These results suggest that endogenous IL-1ß is implicated in the progression of IPH via the inhibition of physiological angiogenesis in the atherosclerotic plaque, leading to the formation of leaky neovessels. Furthermore, the stimulation of MMP-9 expression may also contribute to the formation of leaky neovessels.

Crystalline-Sponge-Based Structural Analysis of Crude Natural Product Extracts.

Characterization of complex natural product mixtures to the absolute structural level of their components often requires significant amounts of starting materials and lengthy purification process, followed by arduous structure elucidation efforts. The crystalline sponge (CS) method has demonstrated utility in the absolute structure elucidation of isolated organic compounds at miniscule quantities compared to conventional methods. In this work, we developed a new CS-based workflow that greatly expedites the in-depth structural analysis of crude natural product extracts. Using a crude extract of the red alga Laurencia pacifica, we showed that CS affinity screening prior to compound isolation enables prioritization of analytes present in the extract, and we subsequently resolved the molecular structures of six sesquiterpenes with stereochemical clarity from around 10 mg crude extract. This study demonstrates a new chemotyping workflow that can greatly accelerate natural product discovery from complex samples.

Permeable Self-Assembled Molecular Containers for Catalyst Isolation Enabling Two-Step Cascade Reactions.

Establishment of a general one-pot cascade reaction protocol would dramatically reduce the effort of multistep organic synthesis. We demonstrate that the unique structure of M12L24 self-assembled complexes gives them the potential to serve as catalyst carriers for enabling continuous chemical transformations. A stereoselective cascade reaction (allylic oxidation followed by Diels-Alder cyclization) with two intrinsically incompatible catalysts was demonstrated. Our system is advantageous in terms of availability, scalability, and predictability.

A Red Algal Bourbonane Sesquiterpene Synthase Defined by Microgram-Scale NMR-Coupled Crystalline Sponge X-ray Diffraction Analysis.

Sesquiterpene scaffolds are the core backbones of many medicinally and industrially important natural products. A plethora of sesquiterpene synthases, widely present in bacteria, fungi, and plants, catalyze the formation of these intricate structures often with multiple stereocenters starting from linear farnesyl diphosphate substrates. Recent advances in next-generation sequencing and metabolomics technologies have greatly facilitated gene discovery for sesquiterpene synthases. However, a major bottleneck limits biochemical characterization of recombinant sesquiterpene synthases: the absolute structural elucidation of the derived sesquiterpene products. Here, we report the identification and biochemical characterization of LphTPS-A, a sesquiterpene synthase from the red macroalga Laurencia pacifica. Using the combination of transcriptomics, sesquiterpene synthase expression in yeast, and microgram-scale nuclear magnetic resonance-coupled crystalline sponge X-ray diffraction analysis, we resolved the absolute stereochemistry of prespatane, the major sesquiterpene product of LphTPS-A, and thereby functionally define LphTPS-A as the first bourbonane-producing sesquiterpene synthase and the first biochemically characterized sesquiterpene synthase from red algae. Our study showcases a workflow integrating multiomics approaches, synthetic biology, and the crystalline sponge method, which is generally applicable for uncovering new terpene chemistry and biochemistry from source-limited living organisms.

Therapeutic Effects of Mesenchymal Stem Cell-Derived Exosomes in Cardiovascular Disease.

Mesenchymal stem cells (MSCs) are multipotent stem cells that reside in various organs. They have the capacity to differentiate into various cell types, including cardiomyocytes, vascular endothelial cells, and vascular smooth muscle cells. Among the various MSCs, bone marrow-derived MSCs (BMMSCs) have been widely used for treating acute myocardial infarction (AMI) and ischemic heart failure (IHF) in preclinical and clinical studies. Although the beneficial effects of BMMSCs in treating AMI and IHF were originally attributed to their capacity to differentiate into cardiac cell types, recent evidence suggests that the differentiation capacity of BMMSCs appears to be minimal and that BMMSCs exert cardioprotective effects by secreting paracrine factors. In this context, MSC-derived exosomes have recently gained much attention. In this chapter, we introduce preclinical studies in which MSC-derived exosomes are used for treating cardiovascular diseases (CVDs) such as AMI, stroke, pulmonary hypertension, and septic cardiomyopathy. Future clinical studies are required to confirm the efficacy of exosome administration in treating CVDs.

Pathophysiology and Management of Cardiovascular Manifestations in Marfan and Loeys-Dietz Syndromes.

Marfan syndrome (MFS) is an autosomal dominant heritable disorder of connective tissue that affects the cardiovascular, skeletal, ocular, pulmonary, and nervous systems and is usually caused by mutations in the FBN1 gene, which encodes fibrillin-1. MFS is traditionally considered to result from the structural weakness of connective tissue. However, recent investigations on molecular mechanisms indicate that increased transforming growth factor-ß (TGF-ß) activity plays a crucial role in the pathogenesis of MFS and related disorders, such as Loeys-Dietz syndrome (LDS), which is caused by mutation in TGF-ß signaling-related genes. In addition, recent studies show that angiotensin II type 1 receptor (AT1R) signaling enhances cardiovascular pathologies in MFS, and the angiotensin II receptor blocker losartan has the potential to inhibit aortic aneurysm formation. However, the relationship between TGF-ß and AT1R signaling pathways remains poorly characterized. In this review, we discuss the recent studies on the molecular mechanisms underlying cardiovascular manifestations of MFS and LDS and the ensuing strategies for management.

Periodontitis May Deteriorate Sinus of Valsalva Dilatation in Marfan Syndrome Patients.

Marfan syndrome (MFS) is a systemic connective tissue disorder that is caused by mutations of fibrillin-1. While MFS patients are at a high risk of periodontitis and aortic diseases, little causal information has been provided to date. To clarify the relationship, their oral condition and sinus of Valsalva (SoV) were evaluated.The subjects were patients with MFS (n = 33) who attended the University of Tokyo Hospital. We divided them into two groups; MFS patients with highly dilated (the diameters were equal to or more than 39 mm) SoV (high group, n = 18) and MFS patients with mildly dilated (less than 39 mm) SoV (mild group, n = 15). Blood examinations, echocardiograms, and full-mouth clinical measurements, including number of teeth, probing pocket depth (PPD), bleeding on probing (BOP), and community periodontal index (CPI) were performed.We found that the high group patients had greater rates of BOP compared to that of the mild group. Furthermore, the high group tended to have higher serum levels of C-reactive protein, matrix metalloproteinase-9, and transforming growth factor-ß compared to the mild group.Periodontitis may deteriorate SoV dilatation in MFS patients.

Involvement of P2Y12 receptor in vascular smooth muscle inflammatory changes via MCP-1 upregulation and monocyte adhesion.

Antiplatelet drugs, frequently used for cardiovascular events with thrombotic involvement, are also regarded as possible promising agents for cardiovascular primary prevention. The roles of P2Y12, an ADP receptor and the target of thienopyridine antiplatelet drugs, are not satisfactorily known in the vascular wall. We investigated the hypothesis that vascular smooth muscle cell (VSMC) P2Y12 is involved in vascular wall inflammatory changes by upregulating monocyte chemoattractant protein-1 (MCP-1) and promoting monocyte adhesion. ADP at 10(-5) M induced a 3.6 ± 0.3-fold upregulation of MCP-1 mRNA in cultured rat VSMCs, which was significantly inhibited by R-138727, the active metabolite of P2Y12 inhibitor prasugrel and siRNAs against P2Y12. ADP also induced MCP-1 protein upregulation, which was diminished by R-138727 and P2Y12 siRNAs. JNK (c-Jun NH2-terminal kinase) inhibition attenuated ADP-induced MCP-1 mRNA and protein upregulation. R-138727 and P2Y12 siRNAs inhibited ADP-induced JNK activation. The reactive oxygen species (ROS) inhibitors N-acetylcysteine (NAC), diphenyleneiodonium (DPI), and Tempol also diminished MCP-1 upregulation and JNK activation induced by ADP. ADP induced MCP-1 promoter activation, which was inhibited by R-138727 and P2Y12 siRNAs. Nuclear factor-κB (NF-κB) consensus sites in the MCP-1 promoter region were involved in this activation. ADP-induced NF-κB pathway activation, examined by a plasmid containing multiple NF-κB sites, was diminished by P2Y12 inhibition. For cellular function analysis, stimulation of VSMC with ADP increased subsequent THP-1 monocyte adhesion. P2Y12 siRNAs and CCR2 antagonism diminished this ADP-induced monocyte adhesion. These data suggested that ADP, via the VSMC P2Y12 receptor, induces vascular inflammatory changes by upregulating MCP-1 and promoting monocyte adhesion.

Congenital contractural arachnodactyly complicated with aortic dilatation and dissection: Case report and review of literature.

Congenital contractural arachnodactyly (CCA) is a connective tissue disease caused by mutations of the FBN2, which encodes fibrillin-2. CCA patients have a marfanoid habitus; however, aortic dilatation and/or dissection as observed in Marfan syndrome have been rarely documented. Here, we report on a Japanese familial case of CCA resulting from a FBN2 splicing mutation (IVS32+5g→a), which leads to exon 32 being skipped, and the patients developed aortic dilatation and type A dissection. Although CCA patients have been believed to have favorable prognoses, repetitive aortic imaging studies must be performed in some patients to detect possible aortic disease early, and genetic testing of FBN2 might be useful to identify such high-risk patients.

High incidence and severity of periodontitis in patients with Marfan syndrome in Japan.

Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the extracellular matrix protein fibrillin-1. While it is known that patients with MFS are at high risk of dental disorders and cardiovascular diseases, little information has been provided to date. To clarify the prevalence of periodontitis in patients with MFS, their oral condition and cardiovascular complications were evaluated. The subjects were patients with MFS (n = 40) who attended the University of Tokyo hospital; age- and gender-matched healthy individuals (n = 14) constituted a control group. Cardiovascular complications and full-mouth clinical measurements, including number of teeth, probing of pocket depth (PD), bleeding on probing (BOP), and community periodontal index (CPI) were recorded. MFS patients had more frequent cardiovascular complications (95 %) compared with the controls (0 %). MFS patients had periodontitis (CPI 3 and 4) more frequently (87.5 %) than the age- and gender-matched control subjects (35.7 %). Furthermore, MFS patients had significantly more severe periodontitis (CPI 2.90 ± 0.12 vs 1.64 ± 0.32) and fewer remaining teeth (26.7 ± 0.4 vs 28.4 ± 0.4) compared with the controls. However, PD and BOP were comparable between MFS patients and the control group. A high incidence of periodontitis and cardiovascular complications was observed in Japanese MFS patients.

Response of urinary liver-type fatty acid-binding protein to contrast media administration has a potential to predict one-year renal outcome in patients with ischemic heart disease.

Urinary liver-type fatty acid-binding proteins (uL-FABP) have recently been recognized as a useful biomarker for predicting contrast-induced nephropathy. Although accumulating studies have evaluated short-term outcomes, its prognostic value for long-term renal prognosis in patients undergoing coronary angiography (CAG) has not been fully examined. This study aimed to evaluate the predictive value of uL-FABP for long-term renal outcome in patients with ischemic heart disease (IHD). Consecutive 24 patients with impaired renal function (serum creatinine >1.2 mg/dL) who underwent CAG were enrolled. uL-FABP was measured before CAG, 24 and 48 h after CAG. The changes in estimated glomerular filtration rate (eGFR) throughout CAG and at 1 year later were compared with the uL-FABP levels. The patients with a greater decrease in eGFR 1 year later had higher uL-FABP levels at all points, but only the value at 48 h after CAG reached statistical significance (lower vs. higher decreased eGFR group, 4.61 ± 3.87 vs. 17.71 ± 12.96; P < 0.01). Measurement of uL-FABP at 48 h after CAG (48h-uL-FABP) showed better correlation with the change in eGFR (pre-CAG uL-FABP vs. 48h-uL-FABP: R = 0.27, P = 0.20 vs. R = 0.65, P < 0.01). Moreover, the high-pre and high-48h-uL-FABP group showed a significantly larger decrease in eGFR compared with the high-pre and low-48h-uL-FABP group (change in eGFR; 8.12 ± 4.06 vs. 1.25 ± 2.23 mL/min/1.73 m2, P < 0.01), although the baseline eGFR levels were similar between these two groups. In this pilot study, measurement of uL-FABP levels at 48 h after CAG may be useful in detecting renal damage, and in predicting 1-year renal outcome in IHD patients undergoing CAG.

Geometrically restricted intermediates in the self-assembly of an M12L24 cuboctahedral complex.

The self-assembly of a cuboctahedral M12 L24 complex is traced by time-dependent NMR spectroscopy and mass spectrometry. The metastable intermediate structures that exist during the self-assembly process are not a chaotic mixture of numerous species, but instead are geometrically restricted. Short-lived M8 L16 (D4d ) and relatively long-lived M9 L18 (D3h ) are fully characterized as major intermediates. Employing a ligand with a smaller bend angle (112°) allows these two species to be kinetically trapped and more clearly observed by NMR spectroscopy. X-ray crystallography shows that M9 L18 has the framework topology predicted by geometric discussion.

A Self-Assembled Spherical Complex Displaying a Gangliosidic Glycan Cluster Capable of Interacting with Amyloidogenic Proteins.

Physiological and pathological functions of glycans are promoted through their clustering effects as exemplified by a series of gangliosides, sialylated glycosphingolipids, which serve as acceptors for bacterial toxins and viruses. Furthermore, ganglioside GM1 clusters on neuronal cell membranes specifically interact with amyloidogenic proteins, triggering their conformational transitions and leading to neurodegeneration. Here we develop a self-assembled spherical complex that displays a cluster of the GM1 pentasaccharide, and successfully demonstrate its ability to interact with amyloidâ€…ß and α-synuclein. Due to the lack of hydrophobic lipid moieties, which would stably trap these cohesive proteins or give rise to toxic aggregates, this artificial cluster enabled NMR spectroscopic characterization of the early encounter stage of protein interactions with its outer carbohydrate moieties, which were not observable with previous glycan clusters.

Emergent ion-gated binding of cationic host-guest complexes within cationic M12L24 molecular flasks.

"Molecular flasks" are well-defined supramolecular cages that can encapsulate one or more molecular guests within their cavities and, in so doing, change the physical properties and reactivities of the guests. Although molecular flasks are powerful tools for manipulating matter on the nanoscale, most of them are limited in their scope because of size restrictions. Recently, however, increasingly large and diverse supramolecular cages have become available with enough space in their cavities for larger chemical systems such as polymers, nanoparticles, and biomolecules. Here we report how a class of metallosupramolecular cages known as M12L24 polyhedra have been adapted to serve as nanometer-scale containers for solutions of a pseudorotaxane host-guest complex based on a tetracationic cyclophane host, cyclobis(paraquat-p-phenylene) (CBPQT(4+)), and a 1,5-dioxynaphthalene (DNP) guest. Remarkably, the hierarchical integration of pseudorotaxanes and M12L24 superhosts causes the system to express stimulus-responsive behavior, a property which can be described as emergent because neither the DNP⊂CBPQT(4+) nor the M12L24 assemblies exhibit this behavior independently. The DNP-containing M12L24 molecular flasks are effectively "sealed off" to CBPQT(4+) until ions are added as a stimulus to "open" them. The electrolyte stimulus reduces the electrostatic screening distance in solution, allowing favorable DNP⊂CBPQT(4+) host-guest interactions to overcome repulsive Coulombic interactions between the cationic M12L24 cages and CBPQT(4+) rings. This unusual example of ion-gated transport into chemical nanocontainers is reminiscent of transmembrane ion channels which act as gates to the cell, with the important difference that this system is reversible and operates at equilibrium.

Adipose-derived stem cells stimulate reendothelialization in stented rat abdominal aorta.

BACKGROUND: Although drug-eluting stents (DES) have been widely used for the treatment of coronary artery disease, they potentially increase the risk of late thrombosis. It is, therefore, desirable to establish a strategy to stimulate reendothelialization. Endothelial injury models have been widely used to analyze the mechanisms of coronary restenosis. However, animal models deployed with coronary stents in the blood vessels are necessary to accurately analyze the mechanisms of coronary restenosis and late thrombosis because persistent inflammation occurs around the coronary stents. METHODS AND RESULTS: Coronary stents were implanted into rat abdominal aorta and adipose tissue-derived stem cells (ASC) were administered from the adventitial side. Reendothelialization was then visualized by Evans blue staining, and neointimal formation was analyzed histologically. ASC significantly stimulated reendothelialization and inhibited neointimal formation in bare metal stents (BMS)-implanted aorta. In addition, ASC promoted reendothelialization in DES-implanted aorta; however, the effects were weaker than in BMS-implanted aorta. Among the cytokines that ASC produce, adrenomedullin (AM) significantly stimulated reendothelialization and inhibited neointimal formation in BMS-implanted aorta, when an adenovirus expressing AM was administered from the adventitial side. CONCLUSIONS: These results suggest that ASC produce several cytokines that stimulate reendothelialization and inhibit neointimal formation in stent-deployed vessels, and that AM could mediate these effects.

Impairment of flow-mediated dilation correlates with aortic dilation in patients with Marfan syndrome.

Marfan syndrome is an inherited disorder characterized by genetic abnormality of microfibrillar connective tissue proteins. Endothelial dysfunction is thought to cause aortic dilation in subjects with a bicuspid aortic valve; however, the role of endothelial dysfunction and endothelial damaging factors has not been elucidated in Marfan syndrome. Flow-mediated dilation, a noninvasive measurement of endothelial function, was evaluated in 39 patients with Marfan syndrome. Aortic diameter was measured at the aortic annulus, aortic root at the sinus of Valsalva, sinotubular junction and ascending aorta by echocardiography, and adjusted for body surface area (BSA). The mean value of flow-mediated dilation was 6.5 ± 2.4 %. Flow-mediated dilation had a negative correlation with the diameter of the ascending thoracic aorta (AscAd)/BSA (R = -0.39, p = 0.020) and multivariate analysis revealed that flow-mediated dilation was an independent factor predicting AscAd/BSA, whereas other segments of the aorta had no association. Furthermore, Brinkman index had a somewhat greater influence on flow-mediated dilation (R = -0.42, p = 0.008). Although subjects who smoked tended to have a larger AscAd compared with non-smokers (AscA/BSA: 17.3 ± 1.8 versus 15.2 ± 3.0 mm/m(2), p = 0.013), there was no significant change in flow-mediated dilation, suggesting that smoking might affect aortic dilation via an independent pathway. Common atherogenic risks, such as impairment of flow-mediated dilation and smoking status, affected aortic dilation in subjects with Marfan syndrome.

Pathophysiology and Japanese clinical characteristics in Marfan syndrome.

Marfan syndrome is an autosomal dominant heritable disorder of the connective tissue, caused by mutations of the gene FBN1, which encodes fibrillin-1, a major component of the microfibrils of the extracellular matrix. Fibrillin-1 interacts with transforming growth factor-ß (TGF-ß), and dysregulated TGF-ß signaling plays a major role in the development of connective tissue disease and familial aortic aneurysm and dissection, including Marfan syndrome. Losartan, an angiotensin II blocker, has the potential to reduce TGF-ß signaling and is expected to be an additional therapeutic option. Clinical diagnosis is made using the Ghent nosology, which requires comprehensive patient assessment and has been proven to work well, but evaluation of some of the diagnostic criteria by a single physician is difficult and time-consuming. A Marfan clinic was established at the University of Tokyo Hospital in 2005, together with cardiologists, cardiac surgeons, pediatricians, orthopedists, and ophthalmologists in one place, for the purpose of speedy and accurate evaluation and diagnosis of Marfan syndrome. In this review, we discuss the recent progress in diagnosis and treatment of Marfan syndrome, and the characteristics of Japanese patients with Marfan syndrome.