Does export dependence imply more political support in Sino-Africa relation since 2000?

published_or_final_versionInternational and Public AffairsMasterMaster of International and Public Affair

TRPV4 mediates cell damage induced by hyperphysiological compression and regulates COX2/PGE2 in intervertebral discs

Background Aberrant mechanical loading of the spine causes intervertebral disc (IVD) degeneration and low back pain. Current therapies do not target the mediators of the underlying mechanosensing and mechanotransduction pathways, as these are poorly understood. This study investigated the role of the mechanosensitive transient receptor potential vanilloid 4 (TRPV4) ion channel in dynamic compression of bovine nucleus pulposus (NP) cells in vitro and mouse IVDs in vivo. Methods Degenerative changes and the expression of the inflammatory mediator cyclooxygenase 2 (COX2) were examined histologically in the IVDs of mouse tails that were dynamically compressed at a short repetitive hyperphysiological regime (vs sham). Bovine NP cells embedded in an agarose-collagen hydrogel were dynamically compressed at a hyperphysiological regime in the presence or absence of the selective TRPV4 antagonist GSK2193874. Lactate dehydrogenase (LDH) and prostaglandin E2 (PGE2) release, as well as phosphorylation of mitogen-activated protein kinases (MAPKs), were analyzed. Degenerative changes and COX2 expression were further evaluated in the IVDs of trpv4-deficient mice (vs wild-type; WT). Results Dynamic compression caused IVD degeneration in vivo as previously shown but did not affect COX2 expression. Dynamic compression significantly augmented LDH and PGE2 releases in vitro, which were significantly reduced by TRPV4 inhibition. Moreover, TRPV4 inhibition during dynamic compression increased the activation of the extracellular signal-regulated kinases 1/2 (ERK) MAPK pathway by 3.13-fold compared to non-compressed samples. Trpv4-deficient mice displayed mild IVD degeneration and decreased COX2 expression compared to WT mice. Conclusions TRPV4 therefore regulates COX2/PGE2 and mediates cell damage induced by hyperphysiological dynamic compression, possibly via ERK. Targeted TRPV4 inhibition or knockdown might thus constitute promising therapeutic approaches to treat patients suffering from IVD pathologies caused by aberrant mechanical stress

Expression and Activity of TRPA1 and TRPV1 in the Intervertebral Disc: Association with Inflammation and Matrix Remodeling

Transient receptor potential (TRP) channels have emerged as potential sensors and transducers of inflammatory pain. The aims of this study were to investigate (1) the expression of TRP channels in intervertebral disc (IVD) cells in normal and inflammatory conditions and (2) the function of Transient receptor potential ankyrin 1 (TRPA1) and Transient receptor potential vanilloid 1 (TRPV1) in IVD inflammation and matrix homeostasis. RT-qPCR was used to analyze human fetal, healthy, and degenerated IVD tissues for the gene expression of TRPA1 and TRPV1. The primary IVD cell cultures were stimulated with either interleukin-1 beta (IL-1β) or tumor necrosis factor alpha (TNF-α) alone or in combination with TRPA1/V1 agonist allyl isothiocyanate (AITC, 3 and 10 µM), followed by analysis of calcium flux and the expression of inflammation mediators (RT-qPCR/ELISA) and matrix constituents (RT-qPCR). The matrix structure and composition in caudal motion segments from TRPA1 and TRPV1 wild-type (WT) and knock-out (KO) mice was visualized by FAST staining. Gene expression of other TRP channels (A1, C1, C3, C6, V1, V2, V4, V6, M2, M7, M8) was also tested in cytokine-treated cells. TRPA1 was expressed in fetal IVD cells, 20% of degenerated IVDs, but not in healthy mature IVDs. TRPA1 expression was not detectable in untreated cells and it increased upon cytokine treatment, while TRPV1 was expressed and concomitantly reduced. In inflamed IVD cells, 10 µM AITC activated calcium flux, induced gene expression of IL-8, and reduced disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and collagen 1A1, possibly via upregulated TRPA1. TRPA1 KO in mice was associated with signs of degeneration in the nucleus pulposus and the vertebral growth plate, whereas TRPV1 KO did not show profound changes. Cytokine treatment also affected the gene expression of TRPV2 (increase), TRPV4 (increase), and TRPC6 (decrease). TRPA1 might be expressed in developing IVD, downregulated during its maturation, and upregulated again in degenerative disc disease, participating in matrix homeostasis. However, follow-up studies with larger sample sizes are needed to fully elucidate the role of TRPA1 and other TRP channels in degenerative disc disease

Towards a global partnership model in interprofessional education for cross-sector problem-solving

Objectives A partnership model in interprofessional education (IPE) is important in promoting a sense of global citizenship while preparing students for cross-sector problem-solving. However, the literature remains scant in providing useful guidance for the development of an IPE programme co-implemented by external partners. In this pioneering study, we describe the processes of forging global partnerships in co-implementing IPE and evaluate the programme in light of the preliminary data available. Methods This study is generally quantitative. We collected data from a total of 747 health and social care students from four higher education institutions. We utilized a descriptive narrative format and a quantitative design to present our experiences of running IPE with external partners and performed independent t-tests and analysis of variance to examine pretest and posttest mean differences in students’ data. Results We identified factors in establishing a cross-institutional IPE programme. These factors include complementarity of expertise, mutual benefits, internet connectivity, interactivity of design, and time difference. We found significant pretest–posttest differences in students’ readiness for interprofessional learning (teamwork and collaboration, positive professional identity, roles, and responsibilities). We also found a significant decrease in students’ social interaction anxiety after the IPE simulation. Conclusions The narrative of our experiences described in this manuscript could be considered by higher education institutions seeking to forge meaningful external partnerships in their effort to establish interprofessional global health education

Human germline heterozygous gain-of-function STAT6 variants cause severe allergic disease

STAT6 (signal transducer and activator of transcription 6) is a transcription factor that plays a central role in the pathophysiology of allergic inflammation. We have identified 16 patients from 10 families spanning three continents with a profound phenotype of early-life onset allergic immune dysregulation, widespread treatment-resistant atopic dermatitis, hypereosinophilia with esosinophilic gastrointestinal disease, asthma, elevated serum IgE, IgE-mediated food allergies, and anaphylaxis. The cases were either sporadic (seven kindreds) or followed an autosomal dominant inheritance pattern (three kindreds). All patients carried monoallelic rare variants in STAT6 and functional studies established their gain-of-function (GOF) phenotype with sustained STAT6 phosphorylation, increased STAT6 target gene expression, and TH2 skewing. Precision treatment with the anti-IL-4Rα antibody, dupilumab, was highly effective improving both clinical manifestations and immunological biomarkers. This study identifies heterozygous GOF variants in STAT6 as a novel autosomal dominant allergic disorder. We anticipate that our discovery of multiple kindreds with germline STAT6 GOF variants will facilitate the recognition of more affected individuals and the full definition of this new primary atopic disorder

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Role of hypoxia inducible factor-alpha (HIF-α) genes inchondrogenesis

Cartilage is an essential skeletal connective tissue in vertebrates. It comprises extracellular matrix components, especially for collagens and proteoglycans. Once the cartilage is damaged, it has limited self-repair capacity. Thus, by understanding the dynamic cellular process of chondrogenesis and chondrocyte differentiation would be necessary in developing therapeutic approaches for cartilage repair. Currently, there is a great interest in the development of cell therapy to repair damaged tissues. In particularly, human mesenchymal stem cells (hMSCs) are attractive candidates for the treatment of skeletal system disorders because they can be greatly expanded ex vivo and they readily differentiate into chondrocytes upon stimulation. Studies have demonstrated low environmental oxygen tension could affect the chondrogenic differentiation of hMSCs. The three basic helix-loop-helix (bHLH) motif-containing hypoxia inducible factor α (HIF-α) subunits (i.e. HIF-1α, HIF-2α and HIF-3α) are the major oxygen-sensitive transcription factors regulating physiological responses under hypoxia. Of significance, HIF-1α has been reported to induce a hyaline chondrocyte-like phenotype in human articular chondrocytes. The aim of this study was to investigate the roles of all three human HIF-α paralogues in chondrogenesis, particularly for the transcriptional regulation of chondrocyte-specific genes, including type II collagen (COL2A1) and aggrecan (AGC1). The effect of all three human HIF-α paralogues on the chondrogenic differentiation of hMSCs could then be investigated. Self-inactivating lentivirus vector (SIN-LV) shuttle plasmids coding for murine SOX9, wild-type and oxygen-insensitive versions of human HIF-1α and HIF-2α or wild-type HIF-3α were generated. These plasmids were used in luciferase-based promoter assays and to generate SIN-LV particles for overexpression studies. Our data revealed that SOX9, a key transactivator of chondrogenesis, strongly activates the transcription of COL2A1 and AGC1. Ectopic expression of HIF-2α could also induce the transcription of COL2A1 and AGC1. Strikingly, a cooperative transcriptional up-regulation of COL2A1 and AGC1 via the overexpression of HIF-1α and SOX9 was observed. Furthermore, HIF-3α was shown to inhibit the SOX9–dependent transcriptional up-regulation of COL2A1 and AGC1. Here, the multipotency of hMSCs cultured under hypoxia (1% O2 tension) was also illustrated. A pilot study for overexpressing exogenous gene in chondrogenic stimulated hMSC pellets via SIN-LV particles is described. Eventually, a rationale is provided for manipulating HIF-α expression in chondrogenic stimulated hMSC pellet via SIN-LVs encoding HIF-α subunits to study the contribution of HIF-α paralogues on promoting the chondrogenic differentiation of hMSCs.published_or_final_versionOrthopaedics and TraumatologyDoctoralDoctor of Philosoph

Investigating an ecosystem approach to environmental protection of Tolo Harbour

published_or_final_versionEnvironmental ManagementMasterMaster of Science in Environmental Managemen