No abstract

Methylmercury (MeHg) is a well known environmental pollutant that induces serious neuronal damage. Although MeHg readily crosses the blood-brain barrier, and should affect both neurons and glial cells, how it affects glia or neuron-to-glia interactions has received only limited attention. Here, we report that MeHg triggers ATP/P2Y1 receptor signals in astrocytes, thereby protecting neurons against MeHg via interleukin-6 (IL-6)-mediated pathways. MeHg increased several mRNAs in astrocytes, among which IL-6 was the highest. For this, ATP/P2Y1 receptor-mediated mechanisms were required because the IL-6 production was (i) inhibited by a P2Y1 receptor antagonist, MRS2179, (ii) abolished in astrocytes obtained from P2Y1 receptor-knockout mice, and (iii) mimicked by exogenously applied ATP. In addition, (iv) MeHg released ATP by exocytosis from astrocytes. As for the intracellular mechanisms responsible for IL-6 production, p38 MAP kinase was involved. MeHg-treated astrocyte-conditioned medium (ACM) showed neuro-protective effects against MeHg, which was blocked by anti-IL-6 antibody and was mimicked by the application of recombinant IL-6. As for the mechanism of neuro-protection by IL-6, an adenosine A1 receptor-mediated pathway in neurons seems to be involved. Taken together, when astrocytes sense MeHg, they release ATP that autostimulates P2Y1 receptors to upregulate IL-6, thereby leading to A1 receptor-mediated neuro-protection against MeHg.

The neurite outgrowth of PC12 cells on collagen-coated glass plates under light emitting diode (LED) irradiation at several wavelengths (i.e., 455, 470, 525, 600, 630, 880 and 945 nm) was investigated. No neurite outgrowth was observed during cultivation under irradiation from the lamp of an inverted light microscope through filters (yielding mixed light at ca. 525 nm and more than 800 nm), whereas neurite outgrowth was observed during cultivation in the dark. When these cells were irradiated with monochromatic LED light, neurite outgrowth was slightly, but not completely, suppressed at 455, 525, 600, 630, 880 and 945 nm, as was observed in the case of mixed light. Long connected neuronal outgrowths (e.g., 3 mm length) were observed with LED light at 470 nm and 1.8 mW/cm(2) intensity. No such outgrowths were observed at other LED light wavelengths (i.e., 455, 525, 600, 630, 880 and 945 nm). Irradiation at 470 nm may have caused specific responses to transductional signals in these cells that led to the connection of neuronal outgrowths between cells. Not only suppressed neurite outgrowth but also long connected neurite outgrowths were observed when PC12 cells were cultured under several different wavelengths of light.

Background Randomized, controlled cardiovascular outcome trials may not be fully representative of the management of patients with type 2 diabetes across different geographic regions. We conducted analyses of data from the multinational CVD-REAL consortium to determine the association between initiation of sodium–glucose cotransporter-2 inhibitors (SGLT-2i) and cardiovascular outcomes, including subgroup analyses based on patient characteristics. Methods De-identified health records from 13 countries across three continents were used to identify patients newly-initiated on SGLT-2i or other glucose-lowering drugs (oGLDs). Propensity scores for SGLT-2i initiation were developed in each country, with 1:1 matching for oGLD initiation. In the matched groups hazard ratios (HRs) for hospitalization for heart failure (HHF), all-cause death (ACD), the composite of HHF or ACD, myocardial infarction (MI) and stroke were estimated by country, and pooled using a weighted meta-analysis. Multiple subgroup analyses were conducted across patient demographic and clinical characteristics to examine any heterogeneity in treatment effects. Results Following matching, 440,599 new users of SGLT-2i and oGLDs were included in each group. Mean follow-up time was 396 days for SGLT-2i initiation and 406 days for oGLDs initiation. SGLT-2i initiation was associated with a lower risk of HHF (HR: 0.66, 95%CI 0.58–0.75; p < 0.001), ACD (HR: 0.52, 95%CI 0.45–0.60; p < 0.001), the composite of HHF or ACD (HR: 0.60, 95%CI 0.53–0.68; p < 0.001), MI (HR: 0.85, 95%CI 0.78–0.92; p < 0.001), and stroke (HR: 0.78, 95%CI 0.72–0.85; p < 0.001); regardless of patient characteristics, including established cardiovascular disease, or geographic region. Conclusions This CVD-REAL study extends the findings from the SGLT-2i clinical trials to the broader setting of an ethnically and geographically diverse population, and across multiple subgroups. Trial registration NCT02993614

We demonstrate the cultivation of diatom cells on a functionalized mica surface and the preparation of frustules on a mica surface by baking. Diatom cells were successfully grown on a mica surface treated with 3-aminopropyltriethoxysilane. After baking at 400˚C for 2 h, frustule structures without the organic components of the diatom cells were successfully observed by scanning electron microscopy and atomic force microscopy. Furthermore, the frustules deformed and became slender when a sample was baked at 800˚C for 2 h. Our method is effective for the direct characterization of frustule structures and physical properties without changing the configuration of the diatom cells grown on the mica surface.