Targeted in vivo extracellular matrix formation promotes neovascularization in a rodent model of myocardial infarction.

BackgroundThe extracellular matrix plays an important role in tissue regeneration. We investigated whether extracellular matrix protein fragments could be targeted with antibodies to ischemically injured myocardium to promote angiogenesis and myocardial repair.Methodology/principal findingsFour peptides, 2 derived from fibronectin and 2 derived from Type IV Collagen, were assessed for in vitro and in vivo tendencies for angiogenesis. Three of the four peptides--Hep I, Hep III, RGD--were identified and shown to increase endothelial cell attachment, proliferation, migration and cell activation in vitro. By chemically conjugating these peptides to an anti-myosin heavy chain antibody, the peptides could be administered intravenously and specifically targeted to the site of the myocardial infarction. When administered into Sprague-Dawley rats that underwent ischemia-reperfusion myocardial infarction, these peptides produced statistically significantly higher levels of angiogenesis and arteriogenesis 6 weeks post treatment.Conclusions/significanceWe demonstrated that antibody-targeted ECM-derived peptides alone can be used to sufficiently alter the extracellular matrix microenvironment to induce a dramatic angiogenic response in the myocardial infarct area. Our results indicate a potentially new non-invasive strategy for repairing damaged tissue, as well as a novel tool for investigating in vivo cell biology

Three-Dimensional Engineered Bone–Ligament–Bone Constructs for Anterior Cruciate Ligament Replacement

The anterior cruciate ligament (ACL), a major stabilizer of the knee, is commonly injured. Because of its intrinsic poor healing ability, a torn ACL is usually reconstructed by a graft. We developed a multi-phasic, or bone?ligament?bone, tissue-engineered construct for ACL grafts using bone marrow stromal cells and sheep as a model system. After 6 months in vivo, the constructs increased in cross section and exhibited a well-organized microstructure, native bone integration, a functional enthesis, vascularization, innervation, increased collagen content, and structural alignment. The constructs increased in stiffness to 52% of the tangent modulus and 95% of the geometric stiffness of native ACL. The viscoelastic response of the explants was virtually indistinguishable from that of adult ACL. These results suggest that our constructs after implantation can obtain physiologically relevant structural and functional characteristics comparable to those of adult ACL. They present a viable option for ACL replacement.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98477/1/ten%2Etea%2E2011%2E0231.pd

Absence of nematic instability in the kagome metal CsV3_3Sb5_5

Ever since the discovery of the charge density wave (CDW) transition in the kagome metal CsV$_3$Sb$_5$, the nature of its symmetry breaking is under intense debate. While evidence suggests that the rotational symmetry is already broken at the CDW transition temperature ($T_{\rm CDW}$), an additional electronic nematic instability well below $T_{\rm CDW}$ was reported based on the diverging elastoresistivity coefficient in the anisotropic channel ($m_{E_{2g}}$). Verifying the existence of a nematic transition below $T_{\rm CDW}$ is not only critical for establishing the correct description of the CDW order parameter, but also important for understanding the low-temperature superconductivity. Here, we report elastoresistivity measurements of CsV$_3$Sb$_5$ using three different techniques probing both isotropic and anisotropic symmetry channels. Contrary to previous reports, we find the anisotropic elastoresistivity coefficient $m_{E_{2g}}$ is temperature-independent except for a step jump at $T_{\rm CDW}$. The absence of nematic fluctuations is further substantiated by measurements of the elastocaloric effect, which show no enhancement associated with nematic susceptibility. On the other hand, the symmetric elastoresistivity coefficient $m_{A_{1g}}$ increases below $T_{\rm CDW}$, reaching a peak value of 90 at $T^* = 20$ K. Our results strongly indicate that the phase transition at $T^*$ is not nematic in nature and the previously reported diverging elastoresistivity is due to the contamination from the $A_{1g}$ channel

Synthesis of metallasiloxanes of group 13-15 and their application in catalysis

973 Program [2012CB821704]; National Nature Science Foundation of China [91027014, 20972129]; National Key Lab Foundation for PCOSS [20923004]; Innovative Research Team Program [IRT1036]Herein we report on the synthesis, characterization and catalytic application of metallasiloxanes of group 13-15. Reactions of R(Me)Si(OH)(2) (R = N(SiMe3)-2,6-iPr(2)C(6)H(3)) (A) with Bi(NEt2)(3), Sb(NEt2)(3), Ge[N(SiMe3)(2)](2) and AlMe3 afforded [R(Me)SiO2BiNEt2](2) (1), [R(Me)SiO2SbOSi(OH)(Me)R](2) (2), [R(Me)SiO2](3)(GeH)(2) (3), and [R(Me)SiO2AlMe(THF)](2) (4), respectively. Reactions of RSi(OH)(3) (B) with Bi(NEt2)(3) and AlMe3 produced complexes (RSiO3Bi)(4) (5) and (RSiO3)(2)[AlMe(THF)](3) (6). Compounds 1-6 have been characterized by IR and NMR spectroscopy, single crystal X-ray structure and elemental analysis. Each of the compounds 1, 2 and 4 features an eight-membered ring of composition Si2O4Bi2, Si2O4Sb2 and Si2O4Al2, while 3 and 6 exhibit a bicyclic structure with the respective skeletons of Si3O6Ge2 and Si2O6Al3. Compound 5 has a cubic core of Si4O12Bi4. Compounds 1-6 exhibit very good catalytic activity in the addition reaction of trimethylsilyl cyanide (TMSCN) with benzaldehyde. Compound 5 was found to be the best catalyst and its activity was probed in the reactions of TMSCN with a number of aldehydes and ketones

Nicotine Overrides DNA Damage-Induced G1/S Restriction in Lung Cells

As an addictive substance, nicotine has been suggested to facilitate pro-survival activities (such as anchorage-independent growth or angiogenesis) and the establishment of drug resistance to anticancer therapy. Tobacco smoking consists of a variety of carcinogens [such as benzopyrene (BP) and nitrosamine derivatives] that are able to cause DNA double strand breaks. However, the effect of nicotine on DNA damage-induced checkpoint response induced by genotoxins remains unknown. In this study, we investigated the events occurred during G1 arrest induced by γ-radiation or BP in nicotine-treated murine or human lung epithelial cells. DNA synthesis was rapidly inhibited after exposure to γ-radiation or BP treatment, accompanied with the activation of DNA damage checkpoint. When these cells were co-treated with nicotine, the growth restriction was compromised, manifested by upregulation of cyclin D and A, and attenuation of Chk2 phosphorylation. Knockdown of cyclin D or Chk2 by the siRNAs blocked nicotine-mediated effect on DNA damage checkpoint activation. However, nicotine treatment appeared to play no role in nocodazole-induced mitotic checkpoint activation. Overall, our study presented a novel observation, in which nicotine is able to override DNA damage checkpoint activated by tobacco-related carcinogen BP or γ-irradiation. The results not only indicates the potentially important role of nicotine in facilitating the establishment of genetic instability to promote lung tumorigenesis, but also warrants a dismal prognosis for cancer patients who are smokers, heavily exposed second-hand smokers or nicotine users

Aspergillus Myosin-V Supports Polarized Growth in the Absence of Microtubule-Based Transport

In the filamentous fungus Aspergillus nidulans, both microtubules and actin filaments are important for polarized growth at the hyphal tip. Less clear is how different microtubule-based and actin-based motors work together to support this growth. Here we examined the role of myosin-V (MYOV) in hyphal growth. MYOV-depleted cells form elongated hyphae, but the rate of hyphal elongation is significantly reduced. In addition, although wild type cells without microtubules still undergo polarized growth, microtubule disassembly abolishes polarized growth in MYOV-depleted cells. Thus, MYOV is essential for polarized growth in the absence of microtubules. Moreover, while a triple kinesin null mutant lacking kinesin-1 (KINA) and two kinesin-3s (UNCA and UNCB) undergoes hyphal elongation and forms a colony, depleting MYOV in this triple mutant results in lethality due to a severe defect in polarized growth. These results argue that MYOV, through its ability to transport secretory cargo, can support a significant amount of polarized hyphal tip growth in the absence of any microtubule-based transport. Finally, our genetic analyses also indicate that KINA (kinesin-1) rather than UNCA (kinesin-3) is the major kinesin motor that supports polarized growth in the absence of MYOV

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

N-P Bond Cleavage Induced Ring Formation of Cyclosilazanes from Reactions of Aryl(phosphanyl)aminotrichlorosilanes with Lithium Alkynyls

973 Program [2012CB821704]; National Nature Science Foundation of China [20972129]; Science Foundation of Ministry of Education of China [2009060011500466]; Innovative Research Team Program [IRT1036]The aryl(silyl)aminotrichlorosilane 2,6-iPr(2)C(6)H(3)N(SiMe2Ph)SiCl3 (1) and aryl(phosphanyl)aminotrichlorosilane ArN(PPh2)SiCl3 (Ar = 2,6-iPr(2)C(6)H(3) (2), 4-MeC6H4 (3), 2,4,6-Me3C6H2 (4)) were prepared and utilized for investigation in reactions with freshly prepared lithium alkynyls. Reaction of 1 with PhC CLi resulted in the compounds PhMe2SiC CPh and 2,6-iPr(2)C(6)H(3)N[Li(THF)(3)]-Si(C CPh)(3) (5), while 2 reacted with R'C CLi to produce the compounds Ph2PC CR' and [2,6-iPr(2)C(6)H(3)NSi(C CR')(2)](2) (R' = Ph (6), tBu (7), CH2CH2Ph (8)). Reaction of 3 with PhC CLi led to the formation of Ph2PC CPh and [4-MeC6H4NSi(C CPh)(2)](3) (9a) as a major product and {4-MeC6H4NSi(C CPh)[N(4-MeC6H4)Si(C CPh)(3)]}(2) (9b) as a minor product. When 4 was reacted with PhC CLi, [2,4,6-Me3C6H2NSi(C CPh)(2)](2) (10a) was isolated as the major product while [(2,4,6-Me3C6H2)(3)N3Si2(C mCPh)(4)Li(THF)](-)[Li-(THF)(4)](+) (10b) was the minor product. The formation of Ph2PC CPh was also detected. All reported compounds were characterized by multinuclear NMR (H-1, C-13, Si-29, and/or P-31) and/or IR spectroscopy, and compounds 2, 5-8, 9a, and 10b were further distinguished by single-crystal X-ray crystallography. These results exhibit a route to the Si2N2- or Si3N3-based cyclosilazanes 6-8, 9a, 9b, and 10a via the N-P bond cleavage of the aryl(phosphanyl)aminotrichlorosilanes during multiple metathesis reactions