Magnesium-Dependent Promotion of H2O2 Production Increases Ecological Competitiveness of Oral Commensal Streptococci

The pyruvate oxidase (SpxB)-dependent production of H₂O₂ is widely distributed among oral commensal streptococci. Several studies confirmed the ability of H₂O₂ to antagonize susceptible oral bacterial species, including caries-associated Streptococcus mutans as well as several periodontal pathobionts. Here we report a potential mechanism to bolster oral commensal streptococcal H₂O₂ production by magnesium (Mg²⁺) supplementation. Magnesium is a cofactor for SpxB catalytic activity, and supplementation increases the production of H₂O₂ in vitro. We demonstrate that Mg²⁺ affects spxB transcription and SpxB abundance in Streptococcus sanguinis and Streptococcus gordonii. The competitiveness of low-passage commensal streptococcal clinical isolates is positively influenced in antagonism assays against S. mutans. In growth conditions normally selective for S. mutans, Mg²⁺ supplementation is able to increase the abundance of S. sanguinis in dual-species biofilms. Using an in vivo biophotonic imaging platform, we further demonstrate that dietary Mg²⁺ supplementation significantly improves S. gordonii oral colonization in mice. In summary, our results support a role for Mg²⁺ supplementation as a potential prebiotic to promote establishment of oral health-associated commensal streptococci.

[Study on the role and possible mechanism of hemeoxygenase-1/carbon monoxide system in protection of quercetin against ethanol-induced hepatocytes oxidative injury]

Objective: To study the protective effect and potential mechanism of heme oxygenase (HO-1)/carbon monoxide (CO)-mediated quercetin on alcoholic oxidative damage of primary rat hepatocytes. Methods: Primary rat hepatocytes were isolated and cultured by two-step collagenase technique. Ethanol exposed primary rat hepatocytes were simultaneously added with quercetin (100 μmol/L) and/or hemoglobin (100 μmol/L) or different doses of CO-releasing molecules (CORM-2, 5-50 μmol/L) for their combined action. After polling, LDH, AST activities and MDA and GSH levels were measured in the supernatant of cell culture. The alone or combined effects of quercetin, CORM-2, hemoglobin and zinc protoporphyrin IX exposed to ethanol were detected by the activity of CYP2E1 in liver microsomes. Statistical analysis of data was performed by analysis of variance (ANOVA) and intergroup comparison was done by SNK-test. Results: Simultaneous addition of 100 μmol/L quercetin had significantly reduced ethanol-induced AST and LDH release, and GSH consumption and MDA elevation extent. Moreover, quercetin had not only lost the hemoglobin (CO blocker) protective effect but also had further exacerbated ethanol-induced lipid peroxidation. CORM-2 had reduced ethanol-induced AST and LDH release, and GSH consumption and MDA production in liver cells, and thus had dose-dependent protective effect. Ethanol had increased significantly CYP2E1 activity. Quercetin or CORM-2 had inhibited CYP2E1 activity, while hemoglobin or protoporphyrin IX had eliminated quercetin inhibitory effect and had increased the CYP2E1 activity. Quercetin, and CYP2E1 activity was constant as compared to ethanol group when CORM-2, zinc protoporphyrin IX and ethanol were incubated with hepatocytes, but the CYP2E1 activity was significantly decreased (P < 0.05), and the differences were statistically significant. Conclusion: CO/HO-1 metabolite mediates the protective effect of quercetin on alcoholic oxidative damage of hepatocytes, which may be related to the inhibition of CYP2E1 activity.

MRI-based radiogenomics analysis for predicting genetic alterations in oncogenic signalling pathways in invasive breast carcinoma

AIM

To investigate the effect of radiomics in the assessment of alterations in canonical cancer pathways in breast cancer.

MATERIALS AND METHODS

Eighty-eight biopsy-proven breast cancer cases were included in the present study. Radiomics features were extracted from T1-weighted sagittal dynamic contrast-enhanced magnetic resonance imaging (MRI) images. Radiomics signatures were developed to predict genetic alterations in the cell cycle, Myc, PI3K, RTK/RAS, and p53 signalling pathways by using hypothesis testing combined with least absolute shrinkage and selection operator (LASSO) regression analysis. The predictive powers of the models were examined by the area under the curve (AUC) of the receiver operating characteristic curve.

RESULTS

A total of 5,234 radiomics features were obtained from MRI images based on the tumour region of interest. Hypothesis tests screened 250, 229, 156, 785, and 319 radiomics features that were differentially displayed between cell cycle, Myc, PI3K, RTK/RAS, and p53 alterations and no alteration status. According to the LASSO algorithm, 11, 12, 12, 15, and 13 features were identified for the construction of the radiomics signatures to predict cell cycle, Myc, PI3K, RTK/RAS, and p53 alterations, with AUC values of 0.933, 0.926, 0.956, 0.940, and 0.886, respectively. The cell cycle radiomics score correlated closely with the RTK/RAS and p53 radiomics scores. These signatures were also dysregulated in patients with different oestrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 statuses.

CONCLUSION

MRI-based radiogenomics analysis exhibits excellent performance in predicting genetic pathways alterations, thus providing a novel approach for non-invasively obtaining genetic-level molecular characteristics of tumours.

A fast key parameter extraction algorithm for long fiber distributed sensing based on Brillouin scattering

A fast key parameter extraction algorithm is proposed to improve the real-time performance of temperature and strain measurements when performing Brillouin scattering-based fiber-distributed sensing. The algorithm uses a new initial value method that takes the extracted key parameters of the current point in the fiber as the initial guesses for the next point. Based on the old and new initial value method, the existing objective method, optimization algorithm, and convergence criterion, the key parameter extraction algorithms developed are implemented in Matlab using the typical Lorentzian, Gaussian, and pseudo-Voigt profiles. These algorithms are used to extract the parameters over a large range of measured Brillouin spectra for the entire fiber with different averaging times. The results reveal that apart from the case when the frequency sweep spans is less than the linewidth and the pseudo-Voigt profile is used (in this case, the mean computation time of the proposed algorithm is 1.1% larger than that of the referenced algorithm), the proposed algorithm not only ensures high accuracy in extracting the key parameters, but also improves the arithmetic efficiency by 16.3%-49.1%.

[Infiltration of tumor associated macrophages in multiple myeloma and its clinical significance]

目的

探讨肿瘤相关性巨噬细胞（TAM）在多发性骨髓瘤（MM）中的临床意义及其与肿瘤血管生成、免疫抑制的关系。

方法

以2015年8月至2017年6月就诊的70例MM患者为观察对象，以20例良性血液病（缺铁性贫血13例，巨幼细胞性贫血7例）患者为对照，采用免疫组化法检测骨髓标本中CD163、CD34、VEGF的表达，采用流式细胞术检测Treg细胞比例，采用ELISA法检测IL-10水平，结合临床特征进行分析。

结果

①70例患者中，男31例，女39例，中位年龄65（50~78）岁。MM患者组的TAM浸润密度、微血管密度（MVD）、VEGF表达水平、Treg细胞比例及IL-10水平均较对照组升高（P值均<0.05）。②在MM患者组中，疾病稳定组（15例）患者的上述指标均较初诊组（35例）和复发难治组（20例）低（P值均<0.05）；后两组差异无统计学意义（P值均>0.05）。③35例初诊MM患者中27例完成4个疗程治疗，有效组（15例）治疗后TAM浸润密度较治疗前明显下降，差异有统计学意义[（20.20±7.66）对（28.87±11.97）个/高倍，t=2.362，P=0.025]；无效组（12例）治疗前后差异无统计学意义[（42.00±13.76）对（48.25±13.59）个/高倍，t=1.119，P=0.275]。④硼替佐米方案治疗有效组患者（21例次）的TAM浸润密度较非硼替佐米方案治疗有效组（18例次）减低[（16.52±4.26）对（19.27±5.82）个/高倍，t=1.662，P=0.170]。⑤MM患者的TAM浸润密度与MVD、VEGF表达水平、Treg细胞比例及IL-10水平呈正相关（P值均<0.001）。

结论

骨髓微环境中浸润的TAM与MM发生、发展、疗效及治疗耐药有关，其作用机制可能与TAM促进肿瘤血管形成及抑制免疫反应有关。

Downregulation of miR-633 activated AKT/mTOR pathway by targeting AKT1 in lupus CD4+ T cells

Background

Accumulating evidence suggests that the AKT/mTOR pathway plays an important role in the pathogenesis of systemic lupus erythematosus (SLE) through activating T cells, and there are few studies looking into the role of microRNA (miRNAs) in the mechanism. We first found that miR-633 expression in CD4+T cells of SLE patients was significantly reduced.

Objective

To investigate the role of miR-633 in the AKT/mTOR pathway in lupus CD4+T cells.

Methods

Samples of 17 SLE cases and 16 healthy controls were collected to detect the expression of miR-633, AKT1, mTOR mRNA and proteins by quantitative polymerase chain reaction (qPCR) and Western-blot, respectively. To determine whether AKT1 is a direct target of miR-633, a luciferase assay was performed. In vitro, AKT1 siRNA, miR-633 mimics/inhibitors or negative controls were transfected to Jurkat cells, human primary CD4+T cells and lupus CD4+T cells. RNA and proteins were extracted after 48 h, and levels of AKT/mTOR pathway markers and downstream multiple cytokines were detected by qPCR or Western-blot.

Results

In SLE patients, the miR-633 levels in CD4+T cells were significantly decreased and negatively correlated with SLEDAI. AKT1, mTOR mRNA and proteins were all up-regulated. The degree of downregulation of miR-633 was correlated negatively with AKT1 mRNA. The luciferase assay proved that AKT1 is a direct target of miR-633. In Jurkat and lupus CD4+T cells, overexpression of miR-633 could result in lower levels of AKT1 and mTOR. Inhibition of miR-633 expression in primary CD4+T cells caused reverse effects, and protein levels of p-AKT, p-mTOR, and p-S6RP increased. Moreover, among various cytokines, the expression of IL-4, IL-17, and IFN-γ mRNA was raised.

Conclusion

Our study suggests that miR-633 deletion can activate the AKT/mTOR pathway by targeting AKT1 to participate in the pathogenesis of SLE.

[Frailty progress and related factors in the elderly living in community: a prospective study]

Objective: To investigate frailty progress status and related factors in the elderly living in communities. Methods: A cohort of elderly people aged 65 and over in Pingyi community of Dujiangyan, Sichuan province, was established. Face-to-face questionnaire survey was conducted by trained interviewers. The frailty status, cognitive function, nutrition status and other functions of the subjects surveyed were evaluated at baseline survey and during follow-up. The socio-demographic and clinical characteristics of the subjects surveyed were assessed at baseline survey. Binary logistic regressions were used to identify factors associated with frailty progress. Results: A total of 653 elderly people were surveyed in January 2014, and 507 elderly people were followed up while 146 elderly people terminated further follow-up in January 2017. The prevalence rates of frailty and pre-frailty at baseline survey were 11.2% (n=57) and 26.2% (n=133), respectively. After 3 years, 205 subjects (40.4%) surveyed experienced frailty progress, 276 (54.5%) remained to be in frailty state at baseline survey, and 26 (5.1%) had improvement. Disability (OR=8.27, 95%CI: 1.62-42.26), visual problem (OR=2.02, 95%CI: 1.27-3.22), cognitive impairment (OR=1.94, 95%CI: 1.08-3.48), poor self-rated health (OR=1.89, 95%CI: 1.07-3.31), chronic pain (OR=1.57, 95%CI: 1.03-2.40) and older age (OR=1.12, 95%CI: 1.08-1.17) were independently associated with the progress of frailty. In contract, overweight was a protective factor (OR=0.54, 95%CI: 0.34-0.85). Conclusions: Frailty is a dynamic syndrome affected by several socio-demographic factors and geriatric factors. The results of the study can be used in the prevention of frailty progress in the elderly in communities.

The interruptive effect of electric shock on odor response requires mushroom bodies in Drosophila melanogaster

Nociceptive stimulus involuntarily interrupts concurrent activities. This interruptive effect is related to the protective function of nociception that is believed to be under stringent evolutionary pressure. To determine whether such interruptive effect is conserved in invertebrate and potentially uncover underlying neural circuits, we examined Drosophila melanogaster. Electric shock (ES) is a commonly used nociceptive stimulus for nociception related research in Drosophila. Here, we showed that background noxious ES dramatically interrupted odor response behaviors in a T-maze, which is termed blocking odor response by electric shock (BOBE). The interruptive effect is not odor specific. ES could interrupt both odor avoidance and odor approach. To identify involved brain areas, we focused on the odor avoidance to 3-OCT. By spatially abolishing neurotransmission with temperature sensitive Shibire^TS1 , we found that mushroom bodies (MBs) are necessary for BOBE. Among the 3 major MB Kenyon cell (KCs) subtypes, α/β neurons and γ neurons but not α'/β' neurons are required for normal BOBE. Specifically, abolishing the neurotransmission of either α/β surface (α/β_s ), α/β core (α/β_c ) or γ dorsal (γ_d ) neurons alone is sufficient to abrogate BOBE. This pattern of MB subset requirement is distinct from that of aversive olfactory learning, indicating a specialized BOBE pathway. Consistent with this idea, BOBE was not diminished in several associative memory mutants and noxious ES interrupted both innate and learned odor avoidance. Overall, our results suggest that MB α/β and γ neurons are parts of a previously unappreciated central neural circuit that processes the interruptive effect of nociception.