Characterization of Peptacetobacter hominis gen. nov., sp. nov., isolated from human faeces, and proposal for the reclassification of Clostridium hiranonis within the genus Peptacetobacter.

A novel, Gram-stain-positive, rod-shaped, non-motile, non-spore-forming, obligately anaerobic bacterium, designated strain ZHW00191T, was isolated from human faeces and characterized by using a polyphasic taxonomic approach. Growth occurred at 25-45 °C (optimum, 37-42 °C), at pH 5.5-10.0 (optimum, pH 6.5-7.0) and with 0-2 % (w/v) NaCl (optimum, 0 %). The end products of glucose fermentation were acetic acid, isobutyric acid and isovaleric acid and a small amount of propionic acid. The dominant cellular fatty acids (>10 %) of strain ZHW00191T were C16 : 0, C18 : 1 ω9с and C18 : 2ω6,9с. Its polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and ten unidentified glycolipids. Respiratory quinones were not detected. The cell-wall peptidoglycan contained meso-2,6-diaminopimelic acid, and the whole-cell sugars were ribose and glucose. The genomic DNA G+C content was 32.8 mol%. Analysis of the 16S rRNA gene sequence indicated that ZHW00191T was most closely related to Clostridium hiranonis TO-931T (95.3 % similarity). Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) analyses with closely related reference strains indicated that reassociation values were both well below the thresholds of 95-96% and 70 % for species delineation, respectively. Based on phenotypic, chemotaxonomic and genetic studies, a novel genus, Peptacetobacter gen. nov., is proposed. The novel isolate ZHW00191T (=JCM 33482T=GDMCC 1.1530T) is proposed as the type strain of the type species Peptacetobacter hominis gen. nov., sp. nov. of the proposed new genus. Furthermore, it is proposed that Clostridium hiranonis be transferred to this novel genus, as Peptacetobacter hiranonis comb. nov.

Corrigendum: MicroRNA Let-7i Is a Promising Serum Biomarker for Post-stroke Cognitive Impairment and Alleviated OGD-Induced Cell Damage in vitro by Regulating Bcl-2.

[This corrects the article DOI: 10.3389/fnins.2020.00215.].

MicroRNA Let-7i Is a Promising Serum Biomarker for Post-stroke Cognitive Impairment and Alleviated OGD-Induced Cell Damage in vitro by Regulating Bcl-2.

Background: The mechanism of post-stroke cognitive impairment (PSCI) has not been explained. We aimed to investigate whether miR-let-7i participates in the PSCI and illuminates its underlying role in oxygen-glucose deprivation (OGD)-induced cell apoptosis. Methods: Blood samples from 36 subjects with PSCI and 38 with post-stroke cognitive normality (Non-PSCI) were collected to evaluate the differential expression of miR-let-7 family members, using qRT-PCT analysis. Spearman correlation was performed to estimate the correlation between the miR-1et-7i level and Montreal Cognitive Assessment (MoCA) score. Treatment of SH-SY5Y cells with OGD was used to induce cell apoptosis in vitro. Effects of miR-let-7i on OGD-induced cell apoptosis was estimated after transfection. The target gene of miR-let-7i was analyzed by dual luciferase reporter gene assay. Results: The expression of miR-let-7i was up-regulated in PSCI patients compared with Non-PSCI (p < 0.001) and negatively correlated with MoCA score (r = -0.643, p < 0.001). When exposed to OGD, SH-SY5Y cells showed significant apoptosis accompanied by miR-let-7i up-regulation. In OGD-treated cells, miR-let-7i up-regulation was accompanied by cell apoptosis, while down-regulation showed the opposite effect. Luciferase reporter assay showed that Bcl-2 was a target gene of miR-let-7i. Western blot showed that miR-let-7i up-regulation promoted Bcl-2 expression, while qRT-PCR showed that miR-let-7i had no effect on Bcl-2 expression. Conclusion: miR-let-7i was overexpressed in PSCI patients and it could be used as a diagnostic biomarker for PSCI. We illuminated the potential mechanism that miR-let-7i alleviated OGD-induced cell damage by targeting Bcl-2 at the post-transcriptional level.

AIF-mediated mitochondrial pathway is critical for the protective effect of diazoxide against SH-SY5Y cell apoptosis.

It has been well established that the mitochondrial ATP-sensitive potassium channel (mitoK(ATP)) opener, diazoxide, has protective effects on the heart and brain following ischemia/reperfusion injury. However, the mechanism of the neuroprotective effects of diazoxide remains unclear. This study highlights the anti-apoptotic effects of the drug, which are mediated by specific regulation of apoptosis-inducing factor (AIF) in the process of oxygen and glucose deprivation (OGD)-induced apoptosis in SH-SY5Y cells. Our data showed that pretreatment with diazoxide in SH-SY5Y cells following OGD concentration-dependently increased cell viability. Compared to cells induced by OGD alone, cells pretreated with diazoxide displayed reduced rates of apoptosis, increased mitochondrial transmembrane potential (ΔΨm), and reduced AIF translocation to the cell nucleus. The protective effects of preconditioning with diazoxide were attenuated by 5-hydroxydecanoic acid (5-HD), a selective mitoK(ATP) channel antagonist. Meanwhile, cell death was blocked in OGD-induced cells stably transfected with the AIF-shRNA plasmid, and down-regulation of AIF reduced the diazoxide-mediated prevention of cell apoptosis as well as the loss of ΔΨm induced by OGD. Taken together, our results demonstrate for the first time that the AIF-mediated mitochondrial pathway plays a critical role in the protective effect of diazoxide against SH-SY5Y cell apoptosis induced by OGD. Diazoxide treatment might represent a novel therapeutic target for the treatment of ischemic cerebrovascular diseases.