Natriuretic peptide receptors regulate cytoprotective effects in a human ex vivo 3D/bioreactor model

© 2013 Peake et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Connexin 43 is overexpressed in human fetal membrane defects after fetoscopic surgery

This project was funded by the RoseTrees Trust (M400, TTC), the QMUL Life Sciences Initiative, Institutional Strategic Support Fund from the Wellcome Trust (105626/Z/14/Z, TTC) and supported by researchers at the National Institute for Health Research, University College London Hospitals Biomedical Research Centre (ALD)

Primary cilia elongation in response to interleukin-1 mediates the inflammatory response

Primary cilia are singular, cytoskeletal organelles present in the majority of mammalian cell types where they function as coordinating centres for mechanotransduction, Wnt and hedgehog signalling. The length of the primary cilium is proposed to modulate cilia function, governed in part by the activity of intraflagellar transport (IFT). In articular cartilage, primary cilia length is increased and hedgehog signaling activated in osteoarthritis (OA). Here, we examine primary cilia length with exposure to the quintessential inflammatory cytokine interleukin-1 (IL-1), which is up-regulated in OA. We then test the hypothesis that the cilium is involved in mediating the downstream inflammatory response. Primary chondrocytes treated with IL-1 exhibited a 50 % increase in cilia length after 3 h exposure. IL-1-induced cilia elongation was also observed in human fibroblasts. In chondrocytes, this elongation occurred via a protein kinase A (PKA)-dependent mechanism. G-protein coupled adenylate cyclase also regulated the length of chondrocyte primary cilia but not downstream of IL-1. Chondrocytes treated with IL-1 exhibit a characteristic increase in the release of the inflammatory chemokines, nitric oxide and prostaglandin E2. However, in cells with a mutation in IFT88 whereby the cilia structure is lost, this response to IL-1 was significantly attenuated and, in the case of nitric oxide, completely abolished. Inhibition of IL-1-induced cilia elongation by PKA inhibition also attenuated the chemokine response. These results suggest that cilia assembly regulates the response to inflammatory cytokines. Therefore, the cilia proteome may provide a novel therapeutic target for the treatment of inflammatory pathologies, including OA

A precision study of the fine tuning in the DiracNMSSM

Recently the DiracNMSSM has been proposed as a possible solution to reduce the fine tuning in supersymmetry. We determine the degree of fine tuning needed in the DiracNMSSM with and without non-universal gaugino masses and compare it with the fine tuning in the GNMSSM. To apply reasonable cuts on the allowed parameter regions we perform a precise calculation of the Higgs mass. In addition, we include the limits from direct SUSY searches and dark matter abundance. We find that both models are comparable in terms of fine tuning, with the minimal fine tuning in the GNMSSM slightly smaller.Comment: 20 pages + appendices, 10 figure

Cx43 regulates mechanotransduction mechanisms in human preterm amniotic membrane defects

Objective: The effects of mechanical stimulation in preterm amniotic membrane (AM) defects were explored. Methods: Preterm AM was collected from women undergoing planned preterm caesarean section (CS) due to fetal growth restriction or emergency CS after spontaneous preterm prelabour rupture of the membranes (sPPROM). AM explants near the cervix or placenta were subjected to trauma and/or mechanical stimulation with the Cx43 antisense. Markers for nuclear morphology (DAPI), myofibroblasts (αSMA), migration (Cx43), inflammation (PGE2) and repair (collagen, elastin and transforming growth factor β [TGFβ1]) were examined by confocal microscopy, second harmonic generation, qPCR and biochemical assays. Results: In preterm AM defects, myofibroblast nuclei were highly deformed and contractile and expressed αSMA and Cx43. Mechanical stimulation increased collagen fibre polarisation and the effects on matrix markers were dependent on tissue region, disease state, gestational age and the number of fetuses. PGE2 levels were broadly similar but reduced after co-treatment with Cx43 antisense in late sPPROM AM defects. TGFβ1 and Cx43 gene expression were significantly increased after trauma and mechanical stimulation but this response dependent on gestational age. Conclusion: Mechanical stimulation affects Cx43 signalling and cell/collagen mechanics in preterm AM defects. Establishing how Cx43 regulates mechanosignalling could be an approach to repair tissue integrity after trauma

Role of Myofibroblasts in the Repair of Iatrogenic Preterm Membranes Subjected to Mechanical Stimulation.

OBJECTIVE: We examined the role of myofibroblasts in regulating Cx43 and collagen structure in iatrogenic preterm amniotic membrane (AM) defects subjected to mechanical stimulation. METHOD: Preterm AM specimens were collected from women undergoing planned preterm caesarean section after in utero intervention for correction of spina bifida by open fetal surgery (n = 4 patients; preterm delivery at 34 + 0 weeks to 35 + 0 weeks). Control specimens taken 5 cm away from the open fetal surgery defect site were compared with wound edge AM. In separate experiments, the effects of mechanical stimulation and co-treatment with Cx43 antisense on matrix and repair proteins were examined. Specimens were immunostained to detect αSMA and Cx43 in myofibroblasts and counterstained with DAPI to quantify nuclei shape. The direction of collagen fibrils in the wound edge region was examined by SHG imaging. Markers for matrix (collagen, elastin, GAG), inflammation (PGE2) and repair (TGFβ1) were examined by RT-qPCR and biochemical assays. RESULTS: In iatrogenic preterm AM specimens, the diameter of the open fetal surgery defect ranged between 3.5 and 7.5 cm. At the wound edge of the open fetal surgery defect, αSMA positive myofibroblasts had deformed nuclei and showed abundant Cx43 localized in the cell bodies or formed plaques. In the fibroblast layer, collagen had degenerated in some regions or had polarity near the wound edge. In preterm AM defects, mechanical stimulation and Cx43 antisense increased the levels of collagen and elastin but not GAG or PGE2 release. Mechanical stimulation increased Cx43 and TGFβ1 gene expression. CONCLUSION: In open fetal surgery defects, myofibroblasts were elongated with collagen fibrils that either degenerated or had polarity. Whilst cells produced substantially higher Cx43 in the fibroblast than in the epithelial layer, they formed plaques, which may prevent migration and delay healing. Mechanical stimulation of preterm AM enhanced matrix repair proteins and the mechanotransduction should be explored to understand how Cx43 contributes to membrane integrity

Role of Myofibroblasts in the Repair of Iatrogenic Preterm Membranes Subjected to Mechanical Stimulation

OBJECTIVE: We examined the role of myofibroblasts in regulating Cx43 and collagen structure in iatrogenic preterm amniotic membrane (AM) defects subjected to mechanical stimulation. METHOD: Preterm AM specimens were collected from women undergoing planned preterm caesarean section after in utero intervention for correction of spina bifida by open fetal surgery (n = 4 patients; preterm delivery at 34 + 0 weeks to 35 + 0 weeks). Control specimens taken 5 cm away from the open fetal surgery defect site were compared with wound edge AM. In separate experiments, the effects of mechanical stimulation and co-treatment with Cx43 antisense on matrix and repair proteins were examined. Specimens were immunostained to detect αSMA and Cx43 in myofibroblasts and counterstained with DAPI to quantify nuclei shape. The direction of collagen fibrils in the wound edge region was examined by SHG imaging. Markers for matrix (collagen, elastin, GAG), inflammation (PGE2) and repair (TGFβ1) were examined by RT-qPCR and biochemical assays. RESULTS: In iatrogenic preterm AM specimens, the diameter of the open fetal surgery defect ranged between 3.5 and 7.5 cm. At the wound edge of the open fetal surgery defect, αSMA positive myofibroblasts had deformed nuclei and showed abundant Cx43 localized in the cell bodies or formed plaques. In the fibroblast layer, collagen had degenerated in some regions or had polarity near the wound edge. In preterm AM defects, mechanical stimulation and Cx43 antisense increased the levels of collagen and elastin but not GAG or PGE2 release. Mechanical stimulation increased Cx43 and TGFβ1 gene expression. CONCLUSION: In open fetal surgery defects, myofibroblasts were elongated with collagen fibrils that either degenerated or had polarity. Whilst cells produced substantially higher Cx43 in the fibroblast than in the epithelial layer, they formed plaques, which may prevent migration and delay healing. Mechanical stimulation of preterm AM enhanced matrix repair proteins and the mechanotransduction should be explored to understand how Cx43 contributes to membrane integrity

Route planning with transportation network maps: an eye-tracking study.

Planning routes using transportation network maps is a common task that has received little attention in the literature. Here, we present a novel eye-tracking paradigm to investigate psychological processes and mechanisms involved in such a route planning. In the experiment, participants were first presented with an origin and destination pair before we presented them with fictitious public transportation maps. Their task was to find the connecting route that required the minimum number of transfers. Based on participants' gaze behaviour, each trial was split into two phases: (1) the search for origin and destination phase, i.e., the initial phase of the trial until participants gazed at both origin and destination at least once and (2) the route planning and selection phase. Comparisons of other eye-tracking measures between these phases and the time to complete them, which depended on the complexity of the planning task, suggest that these two phases are indeed distinct and supported by different cognitive processes. For example, participants spent more time attending the centre of the map during the initial search phase, before directing their attention to connecting stations, where transitions between lines were possible. Our results provide novel insights into the psychological processes involved in route planning from maps. The findings are discussed in relation to the current theories of route planning

Cx43 regulates mechanotransduction mechanisms in human preterm amniotic membrane defects.

OBJECTIVE: The effects of mechanical stimulation in preterm amniotic membrane (AM) defects were explored. METHODS: Preterm AM was collected from women undergoing planned preterm caesarean section (CS) due to fetal growth restriction or emergency CS after spontaneous preterm prelabour rupture of the membranes (sPPROM). AM explants near the cervix or placenta were subjected to trauma and/or mechanical stimulation with the Cx43 antisense. Markers for nuclear morphology (DAPI), myofibroblasts (αSMA), migration (Cx43), inflammation (PGE2 ) and repair (collagen, elastin and transforming growth factor β [TGFβ1 ]) were examined by confocal microscopy, second harmonic generation, qPCR and biochemical assays. RESULTS: In preterm AM defects, myofibroblast nuclei were highly deformed and contractile and expressed αSMA and Cx43. Mechanical stimulation increased collagen fibre polarisation and the effects on matrix markers were dependent on tissue region, disease state, gestational age and the number of fetuses. PGE2 levels were broadly similar but reduced after co-treatment with Cx43 antisense in late sPPROM AM defects. TGFβ1 and Cx43 gene expression were significantly increased after trauma and mechanical stimulation but this response dependent on gestational age. CONCLUSION: Mechanical stimulation affects Cx43 signalling and cell/collagen mechanics in preterm AM defects. Establishing how Cx43 regulates mechanosignalling could be an approach to repair tissue integrity after trauma

Multicomponent Hydrogels for the Formation of Vascularized Bone-like Constructs In Vitro.

The native extracellular matrix (ECM) is a complex gel-like system with a broad range of structural features and biomolecular signals. Hydrogel platforms that can recapitulate the complexity and signaling properties of this ECM would have enormous impact in fields ranging from tissue engineering to drug discovery. Here, we report on the design, synthesis, and proof-of-concept validation of a microporous and nanofibrous hydrogel exhibiting multiple bioactive epitopes designed to recreate key features of the bone ECM. The material platform integrates self-assembly with orthogonal enzymatic cross-linking to create a supramolecular environment comprising hyaluronic acid modified with tyramine (HA-Tyr) and peptides amphiphiles (PAs) designed to promote cell adhesion (RGDS-PA), osteogenesis (Osteo-PA), and angiogenesis (Angio-PA). Through individual and co-cultures of human adipose derived mesenchymal stem cells (hAMSCs) and human umbilical vascular endothelial cells (HUVECs), we confirmed the capacity of the HA-Tyr/RGDS-PA/Osteo-PA/Angio-PA hydrogel to promote cell adhesion as well as osteogenic and angiogenic differentiation in both 2D and 3D setups. Furthermore, using immunofluorescent staining and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), we demonstrated co-differentiation and organization of hAMSCs and HUVECs into 3D aggregates resembling vascularized bone-like constructs