Allosteric optical control of a class B G-protein-coupled receptor

Allosteric regulation promises to open up new therapeutic avenues by increasing drug specificity at G‐protein‐coupled receptors (GPCRs). However, drug discovery efforts are at present hampered by an inability to precisely control the allosteric site. Herein, we describe the design, synthesis, and testing of PhotoETP, a light‐activated positive allosteric modulator of the glucagon‐like peptide‐1 receptor (GLP‐1R), a class B GPCR involved in the maintenance of glucose homeostasis in humans. PhotoETP potentiates Ca(2+), cAMP, and insulin responses to glucagon‐like peptide‐1 and its metabolites following illumination of cells with blue light. PhotoETP thus provides a blueprint for the production of small‐molecule class B GPCR allosteric photoswitches, and may represent a useful tool for understanding positive cooperativity at the GLP‐1R

Glucagon-like peptide-1(7–36) amide is a new incretin/enterogastrone candidate

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72032/1/j.1365-2362.1991.tb01802.x.pd

Polymorphic variants of genes involved in homocysteine metabolism in celiac disease

Celiac disease (CD) is a polygenic chronic enteropathy conferring an increased risk for various nutrient deficiency states. Hyperhomocysteinemia is a frequent finding in CD and may be related to the development of venous thrombosis, cardiovascular disease, and stroke in untreated CD patients. Recently, a possible excess in the frequency of the MTHFR c.677C>T (rs1801133) gene variant in CD patients was reported. The purpose of this study was to determine if there exist differences in the distribution of polymorphic variants of genes involved in homocysteine/methyl group metabolism between CD patients and the general population. A set of 10 gene polymorphisms (MTHFR rs1801133, MTR rs1805087, MTHFD1 rs2236225, MTRR rs1801394, CBS 844ins68, BHMT1 rs7356530 and rs3733890, BHMT2 rs526264 and rs625879, and TCN2 rs1801198) was tested in 134 patients with CD and 160 matched healthy controls. The frequency of the MTR rs1805087 GG genotype in CD patients was lower than in controls (0.01 and 0.06, respectively), although statistical significance was not achieved (P = 0.06). For the other analyzed polymorphisms, there was no evidence of difference in both allelic and genotypic distribution between cases and controls. The exhaustive Multifactor Dimensionality Reduction analysis revealed no combination of interactive polymorphisms predicting the incidence of CD. In contrast to the well-documented clinical observations of increased risks of vascular disease in patients with longstanding untreated CD, in our group of patients no significant association with CD was found for all tested polymorphic variants of genes involved in homocysteine metabolism. These findings should be replicated in studies with a larger sample size

Genomic microsatellites identify shared Jewish ancestry intermediate between Middle Eastern and European populations

<p>Abstract</p> <p>Background</p> <p>Genetic studies have often produced conflicting results on the question of whether distant Jewish populations in different geographic locations share greater genetic similarity to each other or instead, to nearby non-Jewish populations. We perform a genome-wide population-genetic study of Jewish populations, analyzing 678 autosomal microsatellite loci in 78 individuals from four Jewish groups together with similar data on 321 individuals from 12 non-Jewish Middle Eastern and European populations.</p> <p>Results</p> <p>We find that the Jewish populations show a high level of genetic similarity to each other, clustering together in several types of analysis of population structure. Further, Bayesian clustering, neighbor-joining trees, and multidimensional scaling place the Jewish populations as intermediate between the non-Jewish Middle Eastern and European populations.</p> <p>Conclusion</p> <p>These results support the view that the Jewish populations largely share a common Middle Eastern ancestry and that over their history they have undergone varying degrees of admixture with non-Jewish populations of European descent.</p

Cellular resorption of 3D-printed bone implants based on calcium magnesium phosphates

Für die Behandlung von Knochendefekten kritischer Größe gibt es heute eine Reihe von Therapiemöglichkeiten. Neuartige Ansätze mit Magnesiumphosphat- (MPC) und Calciummagnesiumphosphatzementen (CMPC) haben sich als echte Alternativen zu den etablierten Calciumphosphaten erwiesen. Ziel war es, die Osteoklastogenese in vitro auf 3D-pulvergedrucktem CMPC und MPC zu induzieren und die zelluläre Resorption (zR) zu analysieren. Polystyrol (PS), Glas, β-TCP und Brushit-bildender Zement dienten als Referenzen. Als Proben wurden Zemente der allgemeinen stöchiometrischen Summenformel CaxMg(3–x)(PO4)2 (x = 0; 0,25; 0,75; 3) verwendet, die Struvit oder Newberyit enthielten. Für die Osteoklastogenese wurden monozytenangereicherte PBMCs aus Buffy-Coat mittels dreifacher Dichtegradientenzentrifugation isoliert, auf die Prüfoberflächen ausgesät und über einen Zeitraum von 22 Tagen mit Zytokinen (M-CSF und RANKL) stimuliert. Die Interaktion der Zellen mit den Zementen bzw. PS/Glas wurde mittels TRAP-Färbung und -Aktivität, DNA- und Ionenkonzentrationen (Ca2+, Mg2+, PO43–, pH-Wert), Rasterelektronen-, Durchlicht-, Auflicht- und Fluoreszenzmikroskopie analysiert. Auf den Struvit- und Newberyit-bildenden Zementen konnten keine für Osteoklasten typischen Riesenzellen nachgewiesen werden. Auf den Struvit-bildenden Zementen wurde deutlich mehr mononukleäre Zellen nachgewiesen wurden als auf den Newberyit-bildenden Zementen. Während die Freisetzung von Mg2+ und PO43– ausschließlich durch die chemische Degradation erfolgte, wurde Ca2+ zunächst adsorbiert und anschließend durch zR freigesetzt. Die erhöhte Ca2+-Adsorption im Vergleich zur Ca2+-Resorption führte insgesamt zu einer Calcium-Präzipitation. Da lediglich auf β-TCP Resorptionslakunen beobachtet wurden, wird angenommen, dass auf den CMPC, MPC und Brushite-bildenden Zementen die zellvermittelte Ca2+-Freisetzung von den Präzipitaten ausging, die von Makrophagen auf den Zementen und/oder Riesenzellen auf den Wellplatten resorbiert wurden.There are a number of therapeutic options available today for the treatment of critical size bone defects. Novel approaches using magnesium phosphate (MPC) and calcium magnesium phosphate cements (CMPC) have proven to be real alternatives to the established calcium phosphates. The aim was to induce osteoclastogenesis in vitro on 3D powder-printed CMPC and MPC and to analyse cellular resorption (zR). Polystyrene (PS), glass, β-TCP and brushite-forming cement served as references. Cements of the general stoichiometric molecular formula CaxMg(3-x)(PO4)2 (x = 0; 0.25; 0.75; 3) containing struvite or newberyite were used as samples. For osteoclastogenesis, monocyte-enriched PBMCs were isolated from buffy coat by triple density gradient centrifugation, seeded onto the test surfaces and stimulated with cytokines (M-CSF and RANKL) over a period of 22 days. The interaction of the cells with the cements or PS/glass was analysed by TRAP staining and activity, DNA and ion concentrations (Ca2+, Mg2+, PO43-, pH), SEM, transmitted light, reflected light and fluorescence microscopy. No giant cells typical of osteoclasts could be detected on the struvite- and newberyite-forming cements. On the struvite-forming cements, significantly more mononuclear cells were detected than on the newberyite-forming cements. While the release of Mg2+ and PO43- was exclusively by chemical degradation, Ca2+ was first adsorbed and then released by zR. The increased Ca2+ adsorption compared to Ca2+ resorption led to calcium precipitation overall. Since resorption lacunae were only observed on β-TCP, it is assumed that on the CMPC, MPC and Brushite-forming cements, the cell-mediated Ca2+ release originated from the precipitates resorbed by macrophages on the cements and/or giant cells on the well plates