Mode-specific impacts of social distancing measures on the intra- and inter-urban mobility of public transit in Seoul during the COVID-19 pandemic

Social distancing measures (SDMs) mitigated the spread of coronavirus disease 2019 (COVID-19) by reducing human activity and mobility. However, few studies have explored SDMs’ effects on intra- and inter-urban mobility concerning public transit. This study employed the autoregressive integrated moving average with exogenous variables models to examine distinct-level impacts of SDMs on intra- and inter-urban daily ridership by transit in Seoul, South Korea, during the COVID-19 pandemic. This study found: (1) The effect of SDMs on transit mobility was more pronounced for subways than buses, despite both modes experiencing reduced mobility without completely ceasing operations. (2) No substantial disparity was observed between intra- and inter-urban transit mobility. (3) Although other measures effectively curtailed transit mobility, mask-wearing had no statistically significant impact on intra- and inter-urban transit usage. (4) Heightened SDMs (e.g., workplace closures, cancelation of public events, stay-at-home orders) have reduced transit mobility more for railways/subways than buses. These findings underscore the importance of considering the distinct impacts of diverse SDMs on transit mobility, thereby ensuring the sustainable functioning of public transit while mitigating the spread of infectious disease during pandemics

Metabotropic glutamate receptor 5 may be involved in macrophage plasticity

Abstract Background Macrophages are a functionally heterogeneous cell population and depending on microenvironments they polarize in two main groups: M1 and M2. Glutamic acid and glutamate receptors may participate in the regulation of macrophage plasticity. To investigate the role of glutamatergic systems in macrophages physiology, we performed the transfection of mGluR5 cDNAs into RAW-264.7 cells. Results Comparative analysis of modified (RAW-mGluR5 macrophages) and non-modified macrophages (RAW-macrophages) has shown that the RAW-mGluR5 macrophages absorbed more glutamate than control cells and the amount of intracellular glutamate correlated with the expression of excitatory amino acid transporters -2 (EAAT-2). Besides, our results have shown that RAW-mGluR5 macrophages expressed a higher level of peroxisome proliferator-activated receptor γ (PPAR-γ) and secreted more IL-10, high mobility group box 1 proteins (HMGB1) and Galectin-3 than control RAW-macrophages. Conclusions We propose that elevation of intracellular glutamate and expression of mGluR5 may initiate the metabolic rearrangement in macrophages that could contribute to the formation of an immunosuppressive phenotype

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Additional file 1: Figure S1. Expression of mGluR5, EAAT-2, PPAR-γ and HMGB1 proteins in control and mGluR5-transfected macrophages. RAW 264.7 cells (RAW-NT) and mGluR5-transfected macrophages (RAW-mGluR5) (5–105 cells per well) were incubated with LPS (100 ng ⁄ ml) or IL-10 (20 nM) for 24 h, followed by the determination of EAAT-2 (b), PPAR-γ (d) and HMGB1 (f) expression by western blot analysis, as described in the “Methods” section. (h) β-Actin was also visualized by Western blotting to confirm equal loading of the fractions. Data shown are representative of three independent experiments. Quantification of EAAT2 blots shown in c, *P < 0.05, vs corresponding RAW-NT cells. Quantification of PPAR-γ shown in e, *P < 0.05, vs corresponding RAW-NT cells, **P < 0.05, vs mGluR5 control. Quantification of HMGB1 blots shown in g, *P < 0.05, vs corresponding RAW-NT cells

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Additional file 4: Figure S4. Effect of mGluR5 transfection on the HMGB1 and Gal-3 secretion. RAW 264.7 cells (RAW-NT) and mGluR5-transfected macrophages (RAW-mGluR5) (5–105 cells per well) were incubated with LPS (100 ng⁄ml) or IL-10 (20 nM) for 24 h, followed by the determination of HMGB1 proteins (a) and Gal-3 (b), as described in the “Methods” section. Data represented are mean ± SEM of results from four separate experiments performed in duplicate. *P < 0.05, vs RAW-NT control cells. **P < 0.05, vs RAW-mGlur5 control cells

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Additional file 2: Figure S2. Effect of LPS and glutamate on NO and IL-10 secretion. RAW 264.7 cells (RAW-NT) and mGluR5-transfected macrophages (RAW-mGluR5) (5–105 cells per well) were incubated with LPS (100 ng ⁄ ml) or glutamate (40 μM) for 24 h, followed by determination of NO (a) and IL-10 (b) secretion, as described in the “Methods” section. Data represented are mean ± SEM of results from four. separate experiments performed in duplicate. *P < 0.05, vs corresponding RAW-NT cells. **P < 0.05, vs RAW-mGluR5 control cells