Hyaluronic acid influence on platelet-induced airway smooth muscle cell proliferation

Abstract Hyaluronic acid (HA) is one of the main components of the extracellular matrix (ECM) and is expressed throughout the body including the lung and mostly in areas surrounding proliferating and migrating cells. Furthermore, platelets have been implicated as important players in the airway remodeling process, e.g. due to their ability to induce airway smooth muscle cell (ASMC) proliferation. The aim of the present study was to investigate the role of HA, the HA-binding surface receptor CD44 and focal adhesion kinase (FAK) in plateletinduced ASMC proliferation. Proliferation of ASMC was measured using the MTS-assay, and we found that the CD44 blocking antibody and the HA synthase inhibitor 4-Methylumbelliferone (4-MU) significantly inhibited platelet-induced ASMC proliferation. The interaction between ASMC and platelets was studied by fluorescent staining of F-actin. In addition, the ability of ASMC to synthesise HA was investigated by fluorescent staining using biotinylated HA-binding protein and a streptavidin conjugate. We observed that ASMC produced HA and that a CD44 blocking antibody and 4-MU significantly inhibited platelet binding to the area surrounding the ASMC. Furthermore, the FAK-inhibitor PF 573228 inhibited platelet-induced ASMC proliferation. Co-culture of ASMC and platelets also resulted in increased phosphorylation of FAK as detected by Western blot analysis. In addition, 4-MU significantly inhibited the increased FAK-phosphorylation. In conclusion, our findings demonstrate that ECM has the ability to influence platelet-induced ASMC proliferation. Specifically, we propose that HA produced by ASMC is recognised by platelet CD44. The platelet/HA interaction is followed by FAK activation and increased proliferation of co-cultured ASMC. We also suggest that the mitogenic effect of platelets represents a potential important and novel mechanism that may contribute to airway remodelling

Spatial and temporal assessment of rural-urban land-use gradient effects on water quality and periphyton communities in tributaries of Durham Region, Ontario

This study examines the effects of longitudinal and local land-use gradients on water quality and periphyton within four watersheds representing varying rural-urban land-use types and intensities. Although numerous studies have identified how specific land-use gradients (e.g., urban or agricultural land-use) affect water quality and periphyton, it is not fully understood how varying intensities and types of rural-urban land-use gradients affect water quality and algae both within and across watersheds sharing similar physiography and climate. Therefore, this study aimed to determine how variation in rural-urban land-use gradients affect water quality and periphyton along the cumulative flow path of tributaries (i.e., longitudinal), as well as across tributaries where sites were approximately matched for distance from headwaters. To assess spatial variation without the confounding effects of seasonality, I analysed water quality, algal biomass, and community composition from a set of algal growth substrates that were deployed in all study creeks (Lynde, Oshawa, Bowmanville and Soper) during May, 2015. Additionally, I examined the spatial and temporal variation of water quality and algal community structure in all tributaries from May ??? August, 2015

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Platelets and airway remodeling : Mechanisms involved in platelet-induced fibroblast and airway smooth muscle cell proliferation in vitro

Airway remodeling is a contributing cause to the pathological structural changes, such as increased cell proliferation, observed in asthma. Platelets have been found in autopsy lungmaterial obtained from asthmatic patients and are well known to induce proliferation in vitro of a variety of cells. However, the role of platelets in airway remodeling is far from understood. This thesis aims to clarify the involvement of platelets in fibroblast and airway smooth muscle cell (ASMC) proliferation in vitro and to elucidate the importance of HA, FAK, eicosanoid and ROS dependent signaling. The results demonstrate that platelets induce ASMC proliferation through NADPH-oxidase and 5-LOX dependent mechanisms. In addition, platelets also induce a 5-LOX dependent fibroblast proliferation. Furthermore, morphological analysis demonstrates that platelets bind to the extracellular matrix component HA through its receptor CD44 and thereby induce a FAK dependent ASMC proliferation. Taken together, the results obtained in this thesis suggest that platelet/HA interaction mediated through CD44 is of importance for platelets ability to induce cell proliferation. Moreover, the results propose that platelet-induced fibroblast proliferation is 5-LOX dependent and that platelets induce a HA, CD44, FAK, 5-LOX, and ROSdependent ASMC proliferation. This action of platelets represents a potential important and novel mechanism that may have an impact on the remodeling process and in the development of new pharmacological strategies in the treatment of inflammatory respiratory disease such as asthma

Platelets stimulate airway smooth muscle cell proliferation through mechanisms involving 5-lipoxygenase and reactive oxygen species

Continuous recruitment and inappropriate activity of platelets in the airways may contribute to airway remodeling, a characteristic feature of inflammatory airway diseases that includes increased proliferation of the smooth muscle. The aim of the present investigation was to examine the effect of platelets on proliferation of airway smooth muscle cells (ASMC) in culture and to determine the possible role of 5-lipoxygenase (5-LOX) and reactive oxygen species (ROS) in this context. ASMC obtained from guinea pigs were cultured and co-incubated with washed platelets for 24 hours. Thereafter, the proliferation was measured with the MTS-assay, the results were also verified by using thymidine incorporation, DNA measurements and manual counting. The interaction between platelets and ASMC was visualised with fluorescence microscopy. We found that platelets bind to the ASMC and the presence of platelets caused a significant dose-dependent increase in ASMC proliferation. Co-incubation of ASMC with platelets also increased ROS-production, detected by the fluorescent probe DCFDA. Furthermore, the platelet-induced proliferation was reduced in the presence of the NADPH-oxidase inhibitors DPI and apocynin. A possible role of 5-LOX in platelet-induced proliferation and ROS-generation was evaluated by using the 5-LOX inhibitor AA-861 and the PLA2-inhibitor ATK. The results showed that inhibition of these enzymes significantly reduced the platelet-induced proliferation. Moreover, Western blot analysis revealed that the ASMC but not the platelets express 5-LOX. In addition, our experiments revealed that the presence of AA-861 and ATK significantly inhibited the ROS-production generated upon coincubation of platelets and ASMC. In conclusion, we show that platelets have a marked capacity to induce ASMC proliferation. Furthermore, our study indicates that the interaction between platelets and ASMC leads to activation of 5-LOX in the ASMC followed by an increased ROS-production, events resulting in enhanced ASMC proliferation. The new findings are of importance in understanding possible mechanisms contributing to airway remodeling.Original publication: Ann-Charlotte B. Svensson Holm, Torbjörn Bengtsson, Magnus Grenegård and Eva G. Lindström, Platelets stimulate airway smooth muscle cell proliferation through mechanisms involving 5-lipoxygenase and reactive oxygen species, 2008, Platelets, (19), 7, 528-536.http://dx.doi.org/10.1080/09537100802320300. Copyright © Taylor & Francis Group, an informa busines

Una aproximación crítica al monetarismo neoclásico

This article is aimed at assessing the current universal economic thought called Monetarism, especially in its neo-classic variant, represented by US economist Milton Friedman. The paper focuses on the analysis of the historical context that leads Monetarism to become a dominant doctrine, its main methodological features and the notions regarding inflation as a macroeconomic imbalance.En este artículo se valora la corriente de pensamiento económico universal denominada monetarismo, especialmente en su variante neoclásica, representada en la figura del economista norteamericano Milton Friedman. El trabajo se concentra en el análisis del contexto histórico que lleva al monetarismo a constituirse en doctrina dominante, sus rasgos metodológicos principales y sus concepciones acerca de la inflación como desequilibrio macroeconómico

Platelet membranes induce airway smooth muscle cellproliferation

The role of platelets in airway disease is poorly understood although they have been suggested to influence on proliferation of airway smooth muscle cells (ASMC). Platelets have been found localised in the airways in autopsy material from asthmatic patients and have been implicated in airway remodeling. The aim of the present study was to investigate the effects of various platelet fractions on proliferation of ASMC obtained from guinea pigs (GP-ASMC) and humans (H-ASMC). Proliferation of ASMC was measured by the MTS-assay and the results were confirmed by measurements of the DNA content. A key observation was that the platelet membrane preparations induced a significant increase in the proliferation of both GPASMC (129.9 ± 3.0 %) and H-ASMC (144.8 ± 12.2). However, neither supernatants obtained from lysed nor filtrate from thrombin stimulated platelets did induce ASMC proliferation to the same extent as the membrane preparation. We have previously shown the platelet-induced proliferation is dependent on the 5-lipoxygenase (5-LOX) and reactive oxygen species (ROS) pathways. In the present work we established that platelet membrane-induced ASMC proliferation was reduced in the presence of the NADPH oxidase inhibitor DPI and the 5-LOX inhibitor AA-861. In conclusion, our results showed that platelet  membranes significantly induced ASMC proliferation, demonstrating that the mitogenic effect of platelets and platelet membranes on ASMC is mainly due to membrane-associated factors. The effects of platelet membranes were evident on both GP-ASMC and H-ASMC and involved 5-LOX and ROS. These new findings are of importance in understanding the mechanisms contributing to airway remodeling and may contribute to the development of new pharmacological tools in the treatment of inflammatory airway diseases.Original Publication:Ann-Charlotte B. Svensson Holm, Torbjörn Bengtsson, Magnus Grenegård and Eva G. Lindström, Platelet membranes induce airway smooth muscle cellproliferation, 2011, Platelets, (22), 1, 45-55.http://dx.doi.org/10.3109/09537104.2010.515696Copyright: Informa Healthcarehttp://informahealthcare.com

Hair cortisol in horses (Equus caballus) in relation to management regimes, personality and breed

Hair cortisol is a promising biomarker to measure long-term stress since cortisol is incorporated into the hair shaft as it grows. However, few studies have previously assessed hair cortisol concentrations (HCC) in horses. In this study, HCC was evaluated in both mane hair from the neck and body hair from the withers in 153 horses of different breeds, from seven different stables with three different management regimes (Free-roaming horses, Riding school horses, Trotter horses). In addition, 4 hours of behavioral observations were performed at each stable, and for 43 of the horses, a personality survey was completed. Mane and withers HCC correlated moderately, but significantly (rs=0.48, p&lt;0.001). Differences between the stables were found for both mane and withers hair (both p&lt;0.01) and the stable with lowest HCC also showed highest occurrences of positive social and resting behaviors (both p&lt;0.01). There were no significant differences in HCC between the management regimes even though Free-roaming horses showed less negative social behavior compared to Riding school horses (p=0.041) and Trotter horses (p=0.055). The personality traits Dominance, Anxiousness, and Excitability revealed weak to moderate correlations with mane HCC (rs=-0.34, p=0.027; rs=-0.46, p=0.002; rs=-0.31, p=0.043 respectively) which might suggest that personality could also be related to long-term stress levels in horses