Cardiogenesis with a focus on vasculogenesis and angiogenesis

The initial intraembryonic vasculogenesis occurs in the cardiogenic mesoderm. Here, a cell population of proendocardial cells detaches from the mesoderm that subsequently generates the single endocardial tube by forming vascular plexuses. In the course of embryogenesis, the endocardium retains vasculogenic, angiogenic and haematopoietic potential. The coronary blood vessels that sustain the rapidly expanding myocardium develop in the course of the formation of the cardiac loop by vasculogenesis and angiogenesis from progenitor cells of the proepicardial serosa at the venous pole of the heart as well as from the endocardium and endothelial cells of the sinus venosus. Prospective coronary endothelial cells and progenitor cells of the coronary blood vessel walls (smooth muscle cells, perivascular cells) originate from different cell populations that are in close spatial as well as regulatory connection with each other. Vasculo‐ and angiogenesis of the coronary blood vessels are for a large part regulated by the epicardium and epicardium‐derived cells. Vasculogenic and angiogenic signalling pathways include the vascular endothelial growth factors, the angiopoietins and the fibroblast growth factors and their receptors

Cardiovascular development: towards biomedical applicability: Epicardium-derived cells in cardiogenesis and cardiac regeneration

During cardiogenesis, the epicardium grows from the proepicardial organ to form the outermost layer of the early heart. Part of the epicardium undergoes epithelial-mesenchymal transformation, and migrates into the myocardium. These epicardium- derived cells differentiate into interstitial fibroblasts, coronary smooth muscle cells, and perivascular fibroblasts. Moreover, epicardium-derived cells are important regulators of formation of the compact myocardium, the coronary vasculature, and the Purkinje fiber network, thus being essential for proper cardiac development. The fibrous structures of the heart such as the fibrous heart skeleton and the semilunar and atrioventricular valves also depend on a contribution of these cells during development. We hypothesise that the essential properties of epicardium-derived cells can be recapitulated in adult diseased myocardium. These cells can therefore be considered as a novel source of adult stem cells useful in clinical cardiac regeneration therapy

Elucidation of the Fe(III) Gallate Structure in Historical Iron Gall Ink

The article of record as published may be found at http://dx.doi.org/10.1021/acs.analchem.6b00088Synthetic, structural, spectroscopic and aging studies conclusively show that the main colorant of historical iron gall ink (IGI) is an amorphous form of Fe(III) gallate· xH2O (x = ∼1.5−3.2). Comparisons between experimental samples and historical documents, including an 18th century hand-written manuscript by George Washington, by IR and Raman spectroscopy, XRD, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy confirm the relationship between the model and authentic samples. These studies settle controversy in the cultural heritage field, where an alternative structure for Fe(III) gallate has been commonly cited.Library of Congress; Howard Hughes Medical Institute; University of Marylan

Targeted heat activation of HSP promoters in the skin of mammalian animals and humans.

The use of highly inducible HSP promoters for exerting spatial and/or temporal control over the expression of therapeutic transgenes has long been discussed. Localized and time-limited induction of the heat shock response may potentially also be of medical interest. However, such applications would require targeted delivery of heat doses capable of activating HSP promoters in tissues or organs of interest. Accessible areas, including the skin and tissues immediately underneath it, may be most readily targeted. A few applications for heat-directed or heat-controlled therapy in the skin might involve expression of proteins to restore or protect normal skin function, protein antigens for vaccination/immunotherapy, vaccine viruses or even systemically active proteins, e.g., cytokines and chemokines. A review of the literature relating to localized heat activation of HSP promoters and HSP genes in the skin revealed that a multitude of different technologies has been explored in small animal models. In contrast, we uncovered few publications that examine HSP promoter activation in human skin. None of these publications has a therapeutic focus. We present herein two, clinically relevant, developments of heating technologies that effectively activate HSP promoters in targeted regions of human skin. The first development advances a system that is capable of reliably activating HSP promoters in human scalp, in particular in hair follicles. The second development outlines a simple, robust, and inexpensive methodology for locally activating HSP promoters in small, defined skin areas

NMR Evidence for a Short, Strong Hydrogen Bond at the Active Site of a Cholinesterase

Cholinesterases (ChE), use a Glu−His−Ser catalytic triad to enhance the nucleophilicity of the catalytic serine. It has been shown that serine proteases, which employ an Asp−His−Ser catalytic triad for optimal catalytic efficiency, decrease the hydrogen bonding distance between the Asp-His pair to form a short, strong hydrogen bond (SSHB) upon binding mechanism-based inhibitors, which form tetrahedral Ser-adducts, analogous to the tetrahedral intermediates in catalysis, or at low pH when the histidine is protonated [Cassidy, C. S., Lin, J., Frey, P. A. (1997) Biochemistry 36, 4576−4584]. Two types of mechanism-based inhibitors were bound to pure equine butyrylcholinesterase (BChE), a 364 kDa homotetramer, and the complexes were studied by 1H NMR at 600 MHz and 25−37 °C. The downfield region of the 1H NMR spectrum of free BChE at pH 7.5 showed a broad, weak, deshielded resonance with a chemical shift, δ = 16.1 ppm, ascribed to a small amount of the histidine-protonated form. Upon addition of a 3-fold excess of diethyl 4-nitrophenyl phosphate (paraoxon) and subsequent dealkylation, the broad 16.1 ppm resonance increased in intensity 4.7-fold, and yielded a D/H fractionation factor φ = 0.72 ± 0.10 consistent with a SSHB between Glu and His of the catalytic triad. From an empirical correlation of δ with hydrogen-bond length in small crystalline compounds, the length of this SSBH is 2.64 ± 0.04 Å, in agreement with the length of 2.62 ± 0.02 Å independently obtained from φ. The addition of a 3-fold excess of m-(N,N,N-trimethylammonio)trifluoroacetophenone to BChE yielded no signal at 16.1 ppm, and a 640 Hz broad, highly deshielded proton resonance with a chemical shift δ = 18.1 ppm and a D/H fractionation factor φ = 0.63 ± 0.10, also consistent with a SSHB. The length of this SSHB is calculated to be 2.62 ± 0.04 Å from δ and 2.59 ± 0.03 Å from φ. These NMR-derived distances agree with those found in the X-ray structures of the homologous acetylcholinesterase complexed with the same mechanism-based inhibitors, 2.60 ± 0.22 and 2.66 ± 0.28 Å. However, the order of magnitude greater precision of the NMR-derived distances establish the presence of SSHBs. We suggest that ChEs achieve their remarkable catalytic power in ester hydrolysis, in part, due to the formation of a SSHB between Glu and His of the catalytic triad