Mesoporous Silica Nanoparticles Loaded with Surfactant: Low Temperature Magic Angle Spinning 13C and 29Si NMR Enhanced by Dynamic Nuclear Polarization

We show that dynamic nuclear polarization (DNP) can be used to enhance NMR signals of13C and 29Si nuclei located in mesoporous organic/inorganic hybrid materials, at several hundreds of nanometers from stable radicals (TOTAPOL) trapped in the surrounding frozen disordered water. The approach is demonstrated using mesoporous silica nanoparticles (MSN), functionalized with 3-(N-phenylureido)propyl (PUP) groups, filled with the surfactant cetyltrimethylammonium bromide (CTAB). The DNP-enhanced proton magnetization is transported into the mesopores via 1H–1H spin diffusion and transferred to rare spins by cross-polarization, yielding signal enhancements εon/off of around 8. When the CTAB molecules are extracted, so that the radicals can enter the mesopores, the enhancements increase to εon/off ≈ 30 for both nuclei. A quantitative analysis of the signal enhancements in MSN with and without surfactant is based on a one-dimensional proton spin diffusion model. The effect of solvent deuteration is also investigated

Membrane-Associated RING-CH Proteins Associate with Bap31 and Target CD81 and CD44 to Lysosomes

Membrane-associated RING-CH (MARCH) proteins represent a family of transmembrane ubiquitin ligases modulating intracellular trafficking and turnover of transmembrane protein targets. While homologous proteins encoded by gamma-2 herpesviruses and leporipoxviruses have been studied extensively, limited information is available regarding the physiological targets of cellular MARCH proteins. To identify host cell proteins targeted by the human MARCH-VIII ubiquitin ligase we used stable isotope labeling of amino-acids in cell culture (SILAC) to monitor MARCH-dependent changes in the membrane proteomes of human fibroblasts. Unexpectedly, we observed that MARCH-VIII reduced the surface expression of Bap31, a chaperone that predominantly resides in the endoplasmic reticulum (ER). We demonstrate that Bap31 associates with the transmembrane domains of several MARCH proteins and controls intracellular transport of MARCH proteins. In addition, we observed that MARCH-VIII reduced the surface expression of the hyaluronic acid-receptor CD44 and both MARCH-VIII and MARCH-IV sequestered the tetraspanin CD81 in endo-lysosomal vesicles. Moreover, gene knockdown of MARCH-IV increased surface levels of endogenous CD81 suggesting a constitutive involvement of this family of ubiquitin ligases in the turnover of tetraspanins. Our data thus suggest a role of MARCH-VIII and MARCH-IV in the regulated turnover of CD81 and CD44, two ubiquitously expressed, multifunctional proteins

International practice of corticosteroid replacement therapy in congenital adrenal hyperplasia - data from the I-CAH registry.

OBJECTIVE: Despite published guidelines no unified approach to hormone replacement in congenital adrenal hyperplasia (CAH) exists. We aimed to explore geographical and temporal variations in the treatment with glucocorticoids and mineralocorticoids in CAH. DESIGN: This retrospective multi-center study, including 31 centers (16 countries), analyzed data from the International-CAH Registry. METHODS: Data was collected from 461 patients aged 0-18 years with classic 21-hydroxylase deficiency (54.9% females) under follow-up between 1982 - 2018. Type, dose and timing of glucocorticoid and mineralocorticoid replacement was analyzed from 4174 patient visits. RESULTS: The most frequently used glucocorticoid was hydrocortisone (87.6%). Overall, there were significant differences between age groups with regards to daily hydrocortisone-equivalent dose for body surface, with the lowest dose (median with interquartile range) of 12.0 (10.0 - 14.5) mg/ m2/ day at age 1 - 8 years and the highest dose of 14.0 (11.6 - 17.4) mg/ m2/ day at age 12-18 years. Glucocorticoid doses decreased after 2010 in patients 0-8 years (p<0.001) and remained unchanged in patients aged 8-18 years. Fludrocortisone was used in 92% of patients, with relative doses decreasing with age. A wide variation was observed among countries with regards to all aspects of steroid hormone replacement. CONCLUSIONS: Data from the I-CAH Registry suggests international variations in hormone replacement therapy, with a tendency to treatment with high doses in children

INNODIA Master Protocol for the evaluation of investigational medicinal products in children, adolescents and adults with newly diagnosed type 1 diabetes

Background The INNODIA consortium has established a pan-European infrastructure using validated centres to prospectively evaluate clinical data from individuals with newly diagnosed type 1 diabetes combined with centralised collection of clinical samples to determine rates of decline in beta-cell function and identify novel biomarkers, which could be used for future stratification of phase 2 clinical trials. Methods In this context, we have developed a Master Protocol, based on the “backbone” of the INNODIA natural history study, which we believe could improve the delivery of phase 2 studies exploring the use of single or combinations of Investigational Medicinal Products (IMPs), designed to prevent or reverse declines in beta-cell function in individuals with newly diagnosed type 1 diabetes. Although many IMPs have demonstrated potential efficacy in phase 2 studies, few subsequent phase 3 studies have confirmed these benefits. Currently, phase 2 drug development for this indication is limited by poor evaluation of drug dosage and lack of mechanistic data to understand variable responses to the IMPs. Identification of biomarkers which might permit more robust stratification of participants at baseline has been slow. Discussion The Master Protocol provides (1) standardised assessment of efficacy and safety, (2) comparable collection of mechanistic data, (3) the opportunity to include adaptive designs and the use of shared control groups in the evaluation of combination therapies, and (4) benefits of greater understanding of endpoint variation to ensure more robust sample size calculations and future baseline stratification using existing and novel biomarkers