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- Gaengel, K., et al.
(author)
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The Sphingosine-1-Phosphate Receptor S1PR1 Restricts Sprouting Angiogenesis by Regulating the Interplay between VE-Cadherin and VEGFR2
- 2012
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In: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 23:3, s. 587-599
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Journal article (peer-reviewed)abstract
- Angiogenesis, the process by which new blood vessels arise from preexisting ones, is critical for embryonic development and is an integral part of many disease processes. Recent studies have provided detailed information on how angiogenic sprouts initiate, elongate, and branch, but less is known about how these processes cease. Here, we show that S1PR1, a receptor for the blood-borne bioactive lipid sphingosine-1-phosphate (S1P), is critical for inhibition of angiogenesis and acquisition of vascular stability. Loss of S1PR1 leads to increased endothelial cell sprouting and the formation of ectopic vessel branches. Conversely, S1PR1 signaling inhibits angiogenic sprouting and enhances cell-to-cell adhesion. This correlates with inhibition of vascular endothelial growth factor-A (VEGF-A)-induced signaling and stabilization of vascular endothelial (VE)-cadherin localization at endothelial junctions. Our data suggest that S1PR1 signaling acts as a vascular-intrinsic stabilization mechanism, protecting developing blood vessels against aberrant angiogenic responses.
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- Al-Khalili, L, et al.
(author)
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Proteasome inhibition in skeletal muscle cells unmasks metabolic derangements in type 2 diabetes
- 2014
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In: American journal of physiology. Cell physiology. - : American Physiological Society. - 1522-1563 .- 0363-6143. ; 307:9, s. C774-C787
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Journal article (peer-reviewed)abstract
- Two-dimensional difference gel electrophoresis (2-D DIGE)-based proteome analysis has revealed intrinsic insulin resistance in myotubes derived from type 2 diabetic patients. Using 2-D DIGE-based proteome analysis, we identified a subset of insulin-resistant proteins involved in protein turnover in skeletal muscle of type 2 diabetic patients, suggesting aberrant regulation of the protein homeostasis maintenance system underlying metabolic disease. We then validated the role of the ubiquitin-proteasome system (UPS) in myotubes to investigate whether impaired proteasome function may lead to metabolic arrest or insulin resistance. Myotubes derived from muscle biopsies obtained from people with normal glucose tolerance (NGT) or type 2 diabetes were exposed to the proteasome inhibitor bortezomib (BZ; Velcade) without or with insulin. BZ exposure increased protein carbonylation and lactate production yet impaired protein synthesis and UPS function in myotubes from type 2 diabetic patients, marking the existence of an insulin-resistant signature that was retained in cultured myotubes. In conclusion, BZ treatment further exacerbates insulin resistance and unmasks intrinsic features of metabolic disease in myotubes derived from type 2 diabetic patients. Our results highlight the existence of a confounding inherent abnormality in cellular protein dynamics in metabolic disease, which is uncovered through concurrent inhibition of the proteasome system.
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- Domínguez, José L, et al.
(author)
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Effect of the Protonation State of the Titratable Residues on the Inhibitor Affinity to BACE-1
- 2010
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In: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 49:34, s. 7255-7263
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Journal article (peer-reviewed)abstract
- BACE-1 is one of the aspartic proteases involved in the cleavage of beta amyloid peptide, an initial step in the formation of amyloid plaques whose toxicity induces neuron death in Alzheimer's disease patients. One of the central issues in the search of novel BACE-1 inhibitors is the optimum pH for the binding of inhibitors to the enzyme. It is known that the enzyme has optimal catalytic activity at acidic pH, while cell active inhibitors may bind optimally at higher pH. In this work we determine the effect of the pH on the affinities of a set of inhibitors, with a variety of chemical motifs, for the ectodomain region of BACE-1 by a surface plasmon resonance (SPR) biosensor based assay. In order to understand the molecular interactions that underlie the diverse optimum pH for the binding of the various inhibitors as observed experimentally, we have calculated the titration curves for a set of BACE-1 ligand complexes. The results indicate that the pK(a) values of the titratable residues of the protein depend on the nature of the ligand involved, in disagreement with previous work. The enzyme-inhibitor structures with the resulting protonation states at pH values 4.5 and 7.4 served as the starting point for the prediction of the pH-dependent binding ranking. Our calculations reproduced the entire affinity ranking observed upon pH increase and most of the binding trends among inhibitors, especially at low pH. Finally, our cell-based assays indicate a possible correlation between high inhibitor affinity at both acidic and neutral pH values, with optimal cell response, a result that may open new venues for the search of potent BACE-1 inhibitors that are active at the cellular level.
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- Dumas, L, et al.
(author)
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Influence of skin-to-skin contact and rooming-in on early mother-infant interaction: a randomized controlled trial
- 2013
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In: Clinical nursing research. - : SAGE Publications. - 1552-3799 .- 1054-7738. ; 22:3, s. 310-336
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Journal article (peer-reviewed)abstract
- The objective of this research was to study influence of birth routines on mother–infant interaction at Day 4. The present research is part of a longitudinal study where mother–infant pairs were randomized by infant location and apparel. We intended to assess mother–infant interaction from videos filmed at Day 4. A protocol for the assessment/coding of the affective quality of maternal behaviors indicative of early mother–infant interaction was developed and interculturally validated. Results were compared with birth randomization, as to explain impact of birth practices. Findings indicate that separation and swaddling at birth interfered with mother–infant interaction during a breastfeeding session at Day 4; these mothers significantly demonstrated more roughness in their behaviors with their infants at Day 4. Results also show evidences of a sensitive period for separation after birth. Implications are to encourage immediate and uninterrupted skin-to-skin contact at birth, and rooming-in during postpartum, as recommended in World Health Organization/UNICEF Ten Steps for Successful Breastfeeding.
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