Small-molecule lysophosphatidic acid receptor 5 (LPAR5) antagonists: versatile pharmacological tools to regulate inflammatory signaling in BV-2 microglia cells

Lysophosphatidic acid (LPA) species in the extracellular environment induce downstream signaling via six different G protein-coupled receptors (LPAR1-6). These signaling cascades are essential for normal brain development and function of the nervous system. However, in response to acute or chronic central nervous system (CNS) damage, LPA levels increase and aberrant signaling events can counteract brain function. Under neuro-inflammatory conditions signaling along the LPA/LPAR5 axis induces a potentially neurotoxic microglia phenotype indicating the need for new pharmacological intervention strategies. Therefore, we compared the effects of two novel small-molecule LPAR5 antagonists on LPA-induced polarization parameters of the BV-2 microglia cell line. AS2717638 is a selective piperidine-based LPAR5 antagonist (IC(50) 0.038 μM) while compound 3 is a diphenylpyrazole derivative with an IC(50) concentration of 0.7 μM in BV-2 cells. Both antagonists compromised cell viability, however, at concentrations above their IC(50) concentrations. Both inhibitors blunted LPA-induced phosphorylation of STAT1 and STAT3, p65, and c-Jun and consequently reduced the secretion of pro-inflammatory cyto-/chemokines (IL-6, TNFα, IL-1β, CXCL10, CXCL2, and CCL5) at non-toxic concentrations. Both compounds modulated the expression of intracellular (COX-2 and Arg1) and plasma membrane-located (CD40, CD86, and CD206) polarization markers yet only AS2717638 attenuated the neurotoxic potential of LPA-activated BV-2 cell-conditioned medium towards CATH.a neurons. Our findings from the present in vitro study suggest that the two LPAR5 antagonists represent valuable pharmacological tools to interfere with LPA-induced pro-inflammatory signaling cascades in microglia

Combination Forecasts of Bond and Stock Returns: An Asset Allocation Perspective

We investigate the out-of-sample forecasting ability of the HML, SMB, momentum, short-term and long-term reversal factors along with their size and value decompositions on U.S. bond and stock returns for a variety of horizons ranging from the short run (1 month) to the long run (2 years). Our findings suggest that these factors contain significantly more information for future bond and stock market returns than the typically employed financial variables. Combination of forecasts of the empirical factors turns out to be particularly successful, especially from an an asset allocation perspective. Similar findings pertain to the European and Japanese markets

Challenges of rapid migration to fully virtual education in the age of the Corona virus pandemic: experiences from across the world

The social disruption caused by the sudden eruption of the Corona Virus pandemic has shaken the whole world, influencing all levels of education immensely. Notwithstanding there was a lack of preparedness for this global public health emergency which continues to affect all aspects of work and life. The problem is, naturally, multifaceted, fast evolving and complex, affecting everyone, threatening our well-being, the global economy, the environment and all societal and cultural norms and our everyday activities. In a recent UNESCO report it is noted that nearly a billion and a quarter (which is 67,7 % of the total number) of learners have been affected by the Corona Virus pandemic worldwide. The education sector at all levels has been one of the hardest hit sectors particularly as the academic/school year was in full swing. The impact of the pandemic is widespread, representing a health hazard worldwide. Being such, it profoundly affects society as a whole, and its members that are, in particular, i) individuals (the learners, their parents, educators, support staff), ii) schools, training organisations, pedagogical institutions and education systems, iii) quickly transformed policies, methods and pedagogies to serve the newly appeared needs of the latter. Lengthy developments of such scale usually take years of consultation, strategic planning and implementation. In addition to raising awareness across the population of the dangers of the virus transmission and instigating total lockdown, it has been necessary to develop mechanisms for continuing the delivery of education as well as demanding mechanisms for assuring the quality of the educational experience and educational results. There is often scepticism about securing quality standards in such a fast moving situation. Often in the recent past, the perception was that courses and degrees leading to an award are inferior if the course modules (and sometimes its assessment components) were wholly online. Over the last three decades most Higher Education institutions developed both considerable infrastructure and knowhow enabling distance mode delivery schools (Primary and Secondary) had hardly any necessary infrastructure nor adequate knowhow for enabling virtual education. In addition, community education and various training providers were mainly delivered face-to-face and that had to either stop altogether or rapidly convert materials, exercises and tests for online delivery and testing. A high degree of flexibility and commitment was demanded of all involved and particularly from the educators, who undertook to produce new educational materials in order to provide online support to pupils and students. Apart from the delivery mode of education, which is serving for certificated programmes, it is essential to ensure that learners’ needs are thoroughly and continuously addressed and are efficiently supported throughout the Coronavirus or any other future lockdown. The latter can be originated by various causes and reasons that vary in nature, such as natural or socioeconomical. Readiness, thus, in addition to preparedness, is the primary key question and solution when it comes to quality education for any lockdown. In most countries, the compulsory primary and secondary education sectors have been facing a more difficult challenge than that faced by Higher Education. The poor or in many cases non-existent technological infrastructure and low technological expertise of the teachers, instructors and parents, make the delivery of virtual education difficult or even impossible. The latter, coupled with phenomena such as social exclusion and digital divide where thousands of households do not have adequate access to broadband Internet, Wi-Fi infrastructure and personal computers hamper the promising and strenuous virtual solutions. The shockwaves of the sudden demands on all sectors of society and on individuals required rapid decisions and actions. We will not attempt to answer the question “Why was the world unprepared for the onslaught of the Coronavirus pandemic” but need to ascertain the level of preparedness and readiness particularly of the education sector, to effect the required rapid transition. We aimed to identify the challenges, and problems faced by the educators and their institutions. Through first-hand experiences we also identify best practices and solutions reached. Thus we constructed a questionnaire to gather our own responses but also experiences from colleagues and members of our environment, family, friends, and colleagues. This paper reports the first-hand experiences and knowledge of 33 co-authors from 27 institutions and from 13 different countries from Europe, Asia, and Africa. The communication technologies and development platforms used are identified; the challenges faced as well as solutions and best practices are reported. The findings are consolidated into the four areas explored i.e. Development Platforms, Communications Technologies, Challenges/Problems and Solutions/Best Practices. The conclusion summarises the findings into emerging themes and similarities. Reflections on the lasting impact of the effect of Coronavirus on education, limitations of study, and indications of future work complete the paper

Rapid migration from traditional or hybrid to fully virtual education in the age of the coronavirus pandemic: challenges, experiences and views of college and university students

The abrupt outbreak of the coronavirus pandemic throughout the world in March 2020 resulted in the sudden closure of all schools, colleges and universities, institutions, and an unprecedented pivot to remote learning. Students and teachers were confronted with the overwhelming challenge of migrating from the traditional face-to-face or hybrid mode of education to fully virtual learning and assessment environments within an extremely short amount of time. This migration was exceptionally difficult, as it took place halfway through the academic or school year in most countries. While pandemic restrictions currently vary across different regions, the 2020-2021 academic session continues to pose challenges despite the experience gained. In addition to a review of the current state-of-the-art in relation to the effects of COVID-19 on teaching and learning, this paper reports on an empirical study carried out in 26 countries (from Asia, Europe, Africa and America), by 36 academics from 29 academic institutions. Through an extensive global survey of college and university students, information was collected about the challenges (technological, economic, psychological) faced by them, as a result of the pandemic. We also asked the students’ to offer their ideas and suggestions for further improvements in teaching and learning, as we look toward a post-COVID world. In this paper, we address issues relating to the availability of, and accessibility to, necessary digital technologies (e.g., learning and communication platforms), isolation, disconnection, and loneliness among students, the overall impact of the pandemic on learning and academic performance, and the reliability of assessment methods., cybercrime dangers and fake information. A total of 1005 responses to the survey were received and analysed. The results are presented in this paper together with reflections of the authors. The paper concludes with a summary of suggestions for process improvements in distance education, and the need for preventive preparedness in the post-COVID period

Does advancing male age influence the expression levels and localisation patterns of phospholipase C zeta (PLCζ) in human sperm?

Socio-economic factors have led to an increasing trend for couples to delay parenthood. However, advancing age exerts detrimental effects upon gametes which can have serious consequences upon embryo viability. While such effects are well documented for the oocyte, relatively little is known with regard to the sperm. One fundamental role of sperm is to activate the oocyte at fertilisation, a process initiated by phospholipase C zeta (PLCζ), a sperm-specific protein. While PLCζ deficiency can lead to oocyte activation deficiency and infertility, it is currently unknown whether the expression or function of PLCζ is compromised by advancing male age. Here, we evaluate sperm motility and the proportion of sperm expressing PLCζ in 71 males (22–54 years; 44 fertile controls and 27 infertile patients), along with total levels and localisation patterns of PLCζ within the sperm head. Three different statistical approaches were deployed with male age considered both as a categorical and a continuous factor. While progressive motility was negatively correlated with male age, all three statistical models concurred that no PLCζ–related parameter was associated with male age, suggesting that advancing male age is unlikely to cause problems in terms of the sperm’s fundamental ability to activate an oocyt

Spermatozoal sensitive biomarkers to defective protaminosis and fragmented DNA

Human sperm DNA damage may have adverse effects on reproductive outcome. Infertile men possess substantially more spermatozoa with damaged DNA compared to fertile donors. Although the extent of this abnormality is closely related to sperm function, the underlying etiology of ensuing male infertility is still largely controversial. Both intra-testicular and post-testicular events have been postulated and different mechanisms have been proposed to explain the presence of damaged DNA in human spermatozoa. Three among them, i.e. abnormal chromatin packaging, oxidative stress and apoptosis, are the most studied and discussed in the present review. Furthermore, results from numerous investigations are presented, including our own findings on these pathological conditions, as well as the techniques applied for their evaluation. The crucial points of each methodology on the successful detection of DNA damage and their validity on the appraisal of infertile patients are also discussed. Along with the conventional parameters examined in the standard semen analysis, evaluation of damaged sperm DNA seems to complement the investigation of factors affecting male fertility and may prove an efficient diagnostic tool in the prediction of pregnancy outcome

Lysophosphatidic acid via LPA-receptor 5/protein kinase D-dependent pathways induces a motile and pro-inflammatory microglial phenotype

Abstract Background Extracellular lysophosphatidic acid (LPA) species transmit signals via six different G protein-coupled receptors (LPAR1–6) and are indispensible for brain development and function of the nervous system. However, under neuroinflammatory conditions or brain damage, LPA levels increase, thereby inducing signaling cascades that counteract brain function. We describe a critical role for 1-oleyl-2-hydroxy-sn-glycero-3-phosphate (termed “LPA” throughout our study) in mediating a motile and pro-inflammatory microglial phenotype via LPAR5 that couples to protein kinase D (PKD)-mediated pathways. Methods Using the xCELLigence system and time-lapse microscopy, we investigated the migrational response of microglial cells. Different M1 and M2 markers were analyzed by confocal microscopy, flow cytometry, and immunoblotting. Using qPCR and ELISA, we studied the expression of migratory genes and quantitated the secretion of pro-inflammatory cytokines and chemokines, respectively. Different transcription factors that promote the regulation of pro-inflammatory genes were analyzed by western blot. Reactive oxygen species (ROS) and nitric oxide (NO) production, phagocytosis, and microglial cytotoxicity were determined using commercially available assay kits. Results LPA induces MAPK family and AKT activation and pro-inflammatory transcription factors’ phosphorylation (NF-κB, c-Jun, STAT1, and STAT3) that were inhibited by both LPAR5 and PKD family antagonists. LPA increases migratory capacity, induces secretion of pro-inflammatory cytokines and chemokines and expression of M1 markers, enhances production of ROS and NO by microglia, and augments cytotoxicity of microglial cell-conditioned medium towards neurons. The PKD family inhibitor blunted all of these effects. We propose that interference with this signaling axis could aid in the development of new therapeutic approaches to control neuroinflammation under conditions of overshooting LPA production. Conclusions In the present study, we show that inflammatory LPA levels increased the migratory response of microglia and promoted a pro-inflammatory phenotype via the LPAR5/PKD axis. Interference with this signaling axis reduced microglial migration, blunted microglial cytotoxicity, and abrogated the expression and secretion of pro-inflammatory mediators

Additional file 2: Figure S2. of Lysophosphatidic acid via LPA-receptor 5/protein kinase D-dependent pathways induces a motile and pro-inflammatory microglial phenotype

PKD family inhibition abrogates LPA-mediated downstream signaling. (A) BV-2 microglia cells were cultured in 6-well plates, serum-starved overnight and preincubated with CRT0066101 (‘CRT’, 1 μM) for the indicated time periods before incubation with LPA (1 μM) or LPA (1 μM) plus CRT. Cells incubated only with 0.1% BSA or CRT (1 μM) were used as negative control. The phosphorylation states of PKDs, JNK, AKT, ERK1/2, and p38 were detected by immunoblotting and one representative blot for each protein is shown. (B) Densitometric analysis of western blots (N = 3). Results are presented as mean values + SEM (***p < 0.001; compared to control; ## p < 0.01, ### p < 0.001 LPA plus CRT versus LPA; one-way ANOVA with Bonferroni correction). (PPT 777 kb