JAM-A is highly expressed on human hematopoietic repopulating cells and associates with the key hematopoietic chemokine receptor CXCR4

Hematopoietic stem/progenitor cells (HSPCs) reside in specialized bone marrow microenvironmental niches, with vascular elements (endothelial/mesenchymal stromal cells) and CXCR4-CXCL12 interactions playing particularly important roles for HSPC entry, retention and maintenance. The functional effects of CXCL12 are dependent on its local concentration and rely on complex HSPC-niche interactions. Two Junctional Adhesion Molecule family proteins, JAM-B and JAM-C, are reported to mediate HSPC-stromal cell interactions, which in turn regulate CXCL12 production by mesenchymal stromal cells (MSCs). Here, we demonstrate that another JAM family member, JAM-A, is most highly expressed on human hematopoietic stem cells with in vivo repopulating activity (p&lt;0.01 for JAM-Ahigh compared to JAM-AInt or Low cord blood CD34+ cells). JAM-A blockade, silencing and overexpression show that JAM-A contributes significantly (p&lt;0.05) to the adhesion of human HSPCs to IL-1β activated human bone marrow sinusoidal endothelium. Further studies highlight a novel association of JAM-A with CXCR4, with these molecules moving to the leading edge of the cell upon presentation with CXCL12 (p&lt;0.05 compared to no CXCL12). Therefore, we hypothesize that JAM family members differentially regulate CXCR4 function and CXCL12 secretion in the bone marrow niche.</p

Motivators of online vulnerability: the impact of social network site use and FOMO

Continued and frequent use of social network sites (SNS) has been linked to a fear of missing out (FOMO) and online self-promotion in the form of friending and information disclosure. The present paper reports findings from 506 UK based Facebook users (53% male) who responded to an extensive online survey about their SNS behaviours and online vulnerability. Structural equation modelling (SEM) suggests that FOMO mediates the relationship between increased SNS use and decreased self-esteem. Self-promoting SNS behaviours provide more complex mediated associations. Longitudinal support (N = 175) is provided for the notion that decreased self-esteem might motivate a potentially detrimental cycle of FOMO-inspired online SNS use. The research considers the implications of social networking on an individual’s online vulnerability

Teaching technology-mediated collaborative learning for trainee teachers

In a knowledge driven society, secondary education should let students develop appropriate and meaningful skills to live, think and work. To this aim, teachers require specific knowledge and competences about technology-mediated collaborative learning strategies while overcoming preconceptions and general sense of inadequacy towards these learning approaches. This exploratory study focuses on a learning path based on the “Trialogical” Learning Approach to consider the role of technology mediated collaborative learning in the educational development and classroom practices of trainee teachers. A multi-methods approach was used to analyse the collected data. Results indicate a good level of active participation in the activities leading to a general perception of effective learning. Participants report having acquired knowledge and skills, which will improve their professional practice. The positive value of introducing collaboration and technology in the learning path is highlighted