1881 Proceedings of the Ecumenical Methodist Conference

https://place.asburyseminary.edu/wmcproceedings/1007/thumbnail.jp

As in Real Estate, Location Matters: Cellular Expression of Complement Varies Between Macular and Peripheral Regions of the Retina and Supporting Tissues.

The cellular events that dictate the initiation of the complement pathway in ocular degeneration, such as age-related macular degeneration (AMD), is poorly understood. Using gene expression analysis (single cell and bulk), mass spectrometry, and immunohistochemistry, we dissected the role of multiple retinal and choroidal cell types in determining the complement homeostasis. Our scRNA-seq data show that the cellular response to early AMD is more robust in the choroid, particularly in fibroblasts, pericytes and endothelial cells. In late AMD, complement changes were more prominent in the retina especially with the expression of the classical pathway initiators. Notably, we found a spatial preference for these differences. Overall, this study provides insights into the heterogeneity of cellular responses for complement expression and the cooperation of neighboring cells to complete the pathway in healthy and AMD eyes. Further, our findings provide new cellular targets for therapies directed at complement

Environmentally Persistent Free Radicals (EPFRs). 3. Free versus Bound Hydroxyl Radicals in EPFR Aqueous Solutions

Additional experimental evidence is presented for in vitro generation of hydroxyl radicals because of redox cycling of environmentally persistent free radicals (EPFRs) produced after adsorption of 2-monochlorophenol at 230 °C (2-MCP-230) on copper oxide supported by silica, 5% Cu(II)O/silica (3.9% Cu). A chemical spin trapping agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed. Experiments in spiked O17 water have shown that ∼15% of hydroxyl radicals formed as a result of redox cycling. This amount of hydroxyl radicals arises from an exogenous Fenton reaction and may stay either partially trapped on the surface of particulate matter (physisorbed or chemisorbed) or transferred into solution as free OH. Computational work confirms the highly stable nature of the DMPO–OH adduct, as an intermediate produced by interaction of DMPO with physisorbed/chemisorbed OH (at the interface of solid catalyst/solution). All reaction pathways have been supported by ab initio calculations

Agricultural landscape and spatial distribution of Toxoplasma gondii in rural environment: an agent-based model

BACKGROUND: Predicting the spatial distribution of pathogens with an environmental stage is challenging because of the difficulty to detect them in environmental samples. Among these pathogens, the parasite Toxoplasma gondii is the causative agent of the zoonosis toxoplasmosis, which is responsible for public health issues. Oocysts of T. gondii are excreted by infected cats in the environment, where they may survive and remain infectious for intermediate hosts, specifically rodents, during months to years. The landscape structure that determines the density and distribution of cats may thus impact the spatial distribution of T. gondii. In this study, we investigated the influences of rural settings on the spatial distribution of oocysts in the soil. METHOD: We developed a spatially explicit agent based model to study how landscape structures impact on the spatial distribution of T. gondii prevalence in its rodent intermediate host as well as contamination in the environment. The rural landscape was characterized by the location of farm buildings, which provide shelters and resources for the cats. Specifically, we considered two configurations of farm buildings, i.e. inside and outside a village. Simulations of the first setting, with farm buildings inside the village, were validated using data from previous field studies. Then, simulation results of the two settings were compared to investigate the influences of the farm locations. RESULTS: Model predictions showed a steeper relationship between distance to the nearest farm and infection levels when farm buildings, and thus cats, were concentrated in the same area than when the farms were spread over the area. The relationship between distance to the village center and level of environmental contamination also differed between settings with a potential increased risk for inhabitants when farms are located inside the village. Maps of the risk of soil contaminated with oocysts were also derived from the model. CONCLUSION: The agent-based model provides a useful tool to assess the risk of contamination by T. gondii oocysts at a local scale and determine the most at risk areas. Moreover it provides a basis to investigate the spatial dynamics of pathogens with an environmental stage. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1476-072X-13-45) contains supplementary material, which is available to authorized users

As in Real Estate, Location Matters: Cellular Expression of Complement Varies Between Macular and Peripheral Regions of the Retina and Supporting Tissues

The cellular events that dictate the initiation of the complement pathway in ocular degeneration, such as age-related macular degeneration (AMD), is poorly understood. Using gene expression analysis (single cell and bulk), mass spectrometry, and immunohistochemistry, we dissected the role of multiple retinal and choroidal cell types in determining the complement homeostasis. Our scRNA-seq data show that the cellular response to early AMD is more robust in the choroid, particularly in fibroblasts, pericytes and endothelial cells. In late AMD, complement changes were more prominent in the retina especially with the expression of the classical pathway initiators. Notably, we found a spatial preference for these differences. Overall, this study provides insights into the heterogeneity of cellular responses for complement expression and the cooperation of neighboring cells to complete the pathway in healthy and AMD eyes. Further, our findings provide new cellular targets for therapies directed at complement

Spinal cord injury causes a wide-spread, persistent loss of Kir4.1 and glutamate transporter 1: benefit of 17β-oestradiol treatment

During neuronal activity astrocytes function to remove extracellular increases in potassium, which are largely mediated by the inwardly-rectifying potassium channel Kir4.1, and to take up excess glutamate via glutamate transporter 1, a glial-specific glutamate transporter. Here we demonstrate that expression of both of these proteins is reduced by nearly 80% following a crush spinal cord injury in adult male rats, 7 days post-injury. This loss extended to spinal segments several millimetres rostral and caudal to the lesion epicentre, and persisted at 4 weeks post-injury. Importantly, we demonstrate that loss of these two proteins is not a direct result of astrocyte loss, as immunohistochemistry at 7 days and western blots at 4 weeks demonstrate a marked up-regulation in glial fibrillary acidic protein expression. Kir4.1 and glutamate transporter 1 expression were partially rescued by post-spinal cord injury administration of physiological levels of 17β-oestradiol (0.08 mg/kg/day) in vivo. Utilizing an in vitro culture system we demonstrate that 17β-oestradiol treatment (50 nM) is sufficient to increase glutamate transporter 1 protein expression in spinal cord astrocytes. This increase in glutamate transporter 1 protein expression was reversed and Kir4.1 expression reduced in the presence of an oestrogen receptor antagonist, Fulvestrant 182 780 suggesting a direct translational regulation of Kir4.1 and glutamate transporter 1 via genomic oestrogen receptors. Using whole-cell patch-clamp recordings in cultured spinal cord astrocytes, we show that changes in protein expression following oestrogen application led to functional changes in Kir4.1 mediated currents. These findings suggest that the neuroprotective benefits previously seen with 17β-oestradiol after spinal cord injury may be in part due to increased Kir4.1 and glutamate transporter 1 expression in astrocytes leading to improved potassium and glutamate homeostasis