Heteronuclear solid-state magic-angle spinning (MAS) NMR experiments for probing (15)N-(17)O dipolar and J couplings are presented for [(2)H(NH(3)),1-(13)C,(15)N,(17)O(2)]glycine.(2)HCl and [(15)N(2),(17)O(2)]uracil. Two-dimensional (15)N-(17)O correlation spectra are obtained using the R(3)-HMQC experiment; for glycine.(2)HCl, the intensity of the resolved peaks for the CO and C-O(2)H (17)O resonances corresponds to the relative magnitude of the respective (15)N-(17)O dipolar couplings. (17)O-(15)N REDOR curves are presented for glycine.(2)HCl; fits of the initial buildup (DeltaS/S < 0.2) yield effective dipolar couplings in agreement with (+/-20%) the root-sum-squared dipolar couplings determined from the crystal structure. Experimental (15)N-(17)O REAPDOR curves for the (15)N resonances in glycine.(2)HCl and uracil fit well to the universal curve presented by Goldbourt et al. (J. Am. Chem. Soc. 2003, 125, 11194). Heteronuclear (13)C-(17)O and (15)N-(17)O J couplings were experimentally determined from fits of the quotient of the integrated intensity obtained in a heteronuclear and a homonuclear spin-echo experiment, S(Q)(tau) = S(HET)(tau)/S(HOM)(tau). For glycine.(2)HCl, (1)J(CO) was determined as 24.7 +/- 0.2 and 25.3 +/- 0.3 Hz for the CO and C-O(2)H resonances, respectively, while for uracil, the average of the two NH...O hydrogen-bond-mediated J couplings was determined as 5.1 +/- 0.6 Hz. In addition, two-bond intramolecular J couplings, (2)J(OO) = 8.8 +/- 0.9 Hz and (2)J(N1,N3) = 2.7 +/- 0.1 Hz, were determined for glycine.(2)HCl and uracil, respectively. Excellent agreement was found with J couplings calculated using the CASTEP code using geometrically optimized crystal structures for glycine.HCl [(1)J(CO)(CO) = 24.9 Hz, (1)J(CO)(COH) = 27.5 Hz, (2)J(OO) = 7.9 Hz] and uracil [(2h)J(N1,O4) = 6.1 Hz, (2h)J(N3,O4) = 4.6 Hz, (2)J(N1,N3) = 2.7 Hz].

Human mesenchymal stromal cell (hMSC) secretomes have shown to influence the microenvironment upon injury, promoting cytoprotection, angiogenesis, and tissue repair. The angiogenic potential is of particular interest for the treatment of ischemic diseases. Interestingly, hMSC secretomes isolated from different tissue sources have shown dissimilarities with respect to their angiogenic profile. This study compares angiogenesis of hMSC secretomes from adipose tissue (hADSCs), bone marrow (hBMSCs), and umbilical cord Wharton’s jelly (hWJSCs). hMSC secretomes were obtained under xenofree conditions and analyzed by liquid chromatography tandem mass spectrometry (LC/MS-MS). Biological processes related to angiogenesis were found to be enriched in the proteomic profile of hMSC secretomes. hWJSC secretomes revealed a more complete angiogenic network with higher concentrations of angiogenesis related proteins, followed by hBMSC secretomes. hADSC secretomes lacked central angiogenic proteins and expressed most detected proteins to a significantly lower level. In vivo all secretomes induced vascularization of subcutaneously implanted Matrigel plugs in mice. Differences in secretome composition were functionally analyzed with monocyte and endothelial cell (EC) in vitro co-culture experiments using vi-SNE based multidimensional flow cytometry data analysis. Functional responses between hBMSC and hWJSC secretomes were comparable, with significantly higher migration of CD14 ++ CD16 − monocytes and enhanced macrophage differentiation compared with hADSC secretomes. Both secretomes also induced a more profound pro-angiogenic phenotype of ECs. These results suggest hWJSCs secretome as the most potent hMSC source for inflammation-mediated angiogenesis induction, while the potency of hADSC secretomes was lowest. This systematic analysis may have implication on the selection of hMSCs for future clinical studies.

Weak hydrogen bonding in uracil and 4-cyano-4'-ethynylbiphenyl, for which single-crystal diffraction structures reveal close CH...O=C and C[triple bond]CH...N[triple bond]C distances, is investigated in a study that combines the experimental determination of 1H, 13C, and 15N chemical shifts by magic-angle spinning (MAS) solid-state NMR with first-principles calculations using plane-wave basis sets. An optimized synthetic route, including the isolation and characterization of intermediates, to 4-cyano-4'-ethynylbiphenyl at natural abundance and with 13C[triple bond]13CH and 15N[triple bond]C labeling is described. The difference in chemical shifts calculated, on the one hand, for the full crystal structure and, on the other hand, for an isolated molecule depends on both intermolecular hydrogen bonding interactions and aromatic ring current effects. In this study, the two effects are separated computationally by, first, determining the difference in chemical shift between that calculated for a plane (uracil) or an isolated chain (4-cyano-4'-ethynylbiphenyl) and that calculated for an isolated molecule and by, second, calculating intraplane or intrachain nucleus-independent chemical shifts that quantify the ring current effects caused by neighboring molecules. For uracil, isolated molecule to plane changes in the 1H chemical shift of 2.0 and 2.2 ppm are determined for the CH protons involved in CH...O weak hydrogen bonding; this compares to changes of 5.1 and 5.4 ppm for the NH protons involved in conventional NH...O hydrogen bonding. A comparison of CH bond lengths for geometrically relaxed uracil molecules in the crystal structure and for geometrically relaxed isolated molecules reveals differences of no more than 0.002 A, which corresponds to changes in the calculated 1H chemical shifts of at most 0.1 ppm. For the C[triple bond]CH...N[triple bond]C weak hydrogen bonds in 4-cyano-4'-ethynylbiphenyl, the calculated molecule to chain changes are of similar magnitude but opposite sign for the donor 13C and acceptor 15N nuclei. In uracil and 4-cyano-4'-ethynylbiphenyl, the CH hydrogen-bonding donors are sp2 and sp hybridized, respectively; a comparison of the calculated changes in 1H chemical shift with those for the sp3 hybridized CH donors in maltose (Yates et al. J. Am. Chem. Soc. 2005, 127, 10216) reveals no marked dependence on hybridization for weak hydrogen-bonding strength.