Bacillus cereus non-haemolytic enterotoxin activates the NLRP3 inflammasome

Inflammasomes are important for host defence against pathogens and homeostasis with commensal microbes. Here, we show non-haemolytic enterotoxin (NHE) from the neglected human foodborne pathogen Bacillus cereus is an activator of the NLRP3 inflammasome and pyroptosis. NHE is a non-redundant toxin to haemolysin BL (HBL) despite having a similar mechanism of action. Via a putative transmembrane region, subunit C of NHE initiates binding to the plasma membrane, leading to the recruitment of subunit B and subunit A, thus forming a tripartite lytic pore that is permissive to efflux of potassium. NHE mediates killing of cells from multiple lineages and hosts, highlighting a versatile functional repertoire in different host species. These data indicate that NHE and HBL operate synergistically to induce inflammation and show that multiple virulence factors from the same pathogen with conserved function and mechanism of action can be exploited for sensing by a single inflammasome.

Prevalence and cardiovascular risk factors of asymptomatic intracranial arterial stenosis: the Kongcun Town Study in Shandong, China

BACKGROUND AND PURPOSE

This study was to investigate the prevalence and cardiovascular risk factors (CRFs) of asymptomatic intracranial atherosclerotic stenosis (aICAS) amongst middle-aged and older adults living in rural communities in China.

METHODS

This population-based study included 2019 subjects (aged ≥40 years, 52.3% women) who were free of stroke and living in rural communities in China. From October 2017 to May 2018, data on demographics, CRFs and health conditions were collected through face-to-face interviews, physical examination and laboratory tests. Asymptomatic ICAS was detected through a two-phase procedure: a screening phase with transcranial Doppler ultrasound, followed by a diagnostic phase with magnetic resonance angiography examination. Multivariable logistic regression models were used to analyse CRFs associated with aICAS.

RESULTS

Of the 2019 participants, aICAS was detected in 153 persons. The overall prevalence of aICAS was 7.6%, and the prevalence of moderate-to-severe aICAS was 5.0%. The multi-adjusted odds ratio (95% confidence interval) of aICAS associated with CRFs was 2.40 (1.56-3.69) for hypertension, 1.91 (1.32-2.76) for high hypersensitive C-reactive protein, 1.68 (1.14-2.49) for diabetes and 1.61 (1.08-2.41) for overweight or obesity. When these four CRFs were aggregated, compared with participants without any of these factors, the multi-adjusted odds ratios (95% confidence interval) of aICAS for persons concurrently having one, two and three or more of these factors were 1.14 (0.52-2.48), 2.91 (1.42-5.99) and 5.51 (2.64-11.50), respectively (P for linear trend <0.001).

CONCLUSIONS

Asymptomatic ICAS is common amongst rural-dwelling middle-aged and older Chinese people. Hypertension, diabetes, overweight or obesity and high hypersensitive C-reactive protein, especially when coexisting, are strongly associated with aICAS.

P5386Transplantation of endothelial progenitor cells in the treatment of coronary artery microembolism in rats

Objective

As the impairment of myocardial micro-environments due to coronary micro-embolization (CME) compromises the treatment effect of percutaneous coronary intervention and leads to adverse prognosis, we hypothesized that endothelial progenitor cells (EPCs) transplantation could improve cardiac function in the condition of CME.

Materials and methods

Low- (2×105) and high- (2×106) dose rat bone marrow-derived EPCs were transplanted in a model of CME. To develop a CME model, rats were injected with autologous micro-blood clots into the left ventricle. Echocardiography was examined before and 1, 7, and 28 days after EPC transplantation; serum cTNI, vWF,and cardiac microRNA expression were examined one day after EPCs transplantation. Heart morphology and VEGF, vWF, and bFGF expression were examined one day after EPC transplantation.

Figure 1. Results

Results

After 10 days of culture inductions, BM-EPCs have high purity as confirmed by flow cytometry. Cardiac function reflected by LVEF significantly decreased after CME treatment and rescued by low-dose EPC. Compared to the sham group, cTNI, and vWF serum levels increased significantly after CME treatment and rescued by low-dose EPC and high-dose EPC. Low-dose EPC treatment decreased myocardial necrosis and fibrosis and elevated cardiac expression of VEGF and vWF, while decreasing the cardiac expression of bFGF. Low-dose EPC treatment significantly suppressed cardiac expression of microRNA-19a but significantly enhanced microRNA-21, microRNA-214, and microRNA-486-3p expression. In conclusion, our results indicate that low-dose EPC transplantation may play a pro-angiogenic, anti-fibroblast, anti-fibrosis, and anti-necrosis role and enhance cardiac function in a rat model of CME through a microRNA-related pathway.

Acknowledgement/Funding

Supported by the State Key Laboratory of Low-Dimensional Quantum Physics Open Project Fund (No. KF201608)

Transcriptomes in rat sciatic nerves at different stages of experimental autoimmune neuritis determined by RNA sequencing

Guillain-Barré syndrome (GBS) is characterized by acute immune-mediated peripheral neuropathy, which may result in rapidly progressive paralysis and fatal respiratory failure. As the underlying pathological mechanisms of GBS are unclear, we surveyed the transcriptome of rats with experimental autoimmune neuritis (EAN), a model of GBS. Briefly, sciatic nerves on both sides were collected from 8-10-week-old Lewis rats during early (10 days post-induction), peak (19 days) and late neuritis (30 days). Total RNA was sequenced to identify differentially expressed genes. Compared to control rats without induced neuritis, 33 genes were differentially expressed in the early phase (14 up-regulated and 19 down-regulated), with an adjusted P-value < 0·05 and |log₂ fold-change| >1, as were 137 genes in the peak phase (126 up-regulated and 11 down-regulated) and 60 genes in the late phase (58 up-regulated and two down-regulated). Eleven of these genes were common to all stages, suggesting their crucial roles throughout the disease course. Analysis of protein-protein interactions revealed Fos, Ccl2, Itgax and C3 as node genes at different stages. Functional analysis of differentially expressed genes identified biological processes and pathways that are activated as neuritis progresses. This is the first genomewide gene expression study of peripheral nerves in experimental autoimmune neuritis model. Dynamic gene expression and significantly altered biological functions were detected in different phases of the disease, increasing our understanding of the molecular mechanisms underlying EAN and highlighting potential targets for its diagnosis and treatment.

[Marrow megakaryocyte count as a response predictor of severe thrombocytopenia in patients with primary Sjögren syndrome]

Objective: To explore the predictive factors for determining the therapeutic response and prognosis of severe thrombocytopenia (TP) in patients with primary Sjögren syndrome(pSS). Method: Patients with pSS and severe TP (platelet count ≤ 50×10(9)/L) admitted between 2010 to 2016 at Peking Union Medical College Hospital were classified according to their therapeutic response and analyzed retrospectively. The response parameters and clinical data including bone marrow aspiration results and laboratory findings were collected. Result: Thirty patients were finally analyzed, including twenty with appreciable bone marrow aspiration results. Fourteen and 7 patients achieved a complete response (CR) and a partial response (PR) respectively, other 9 patients with no response (NR). The megakaryocyte counts in bone marrow (BM-MK) counts per slide in each group were 13.0 (9.2,23.5) in CR patients, 7.0 (7.0,20.0) in PR patients, and 5.0 (1.0,6.0) in NR patients. BM-MK counts in patients with clinical response (CR+PR) were significantly higher than those with NR (P=0.006). A receiver-operation characteristic analysis revealed a cutoff value of BM-MK counts at 6.5 per slide stratifying patients by different responses with a sensitivity of 13/14, a specificity of 6/7, and area under the curve of 0.879. Univariate analysis indicated a better prognosis as BM-MK counts>6.5 per slide. Conclusion: BM-MK count could be a predictive factor of response in patients with pSS and severe TP. Patients with BM-MK counts≤6.5 per slide represent worse platelet improvement..

Quercetin Prevents Escherichia coli O157:H7 Adhesion to Epithelial Cells via Suppressing Focal Adhesions

The attachment of Escherichia coli O157:H7 to intestinal epithelial cells is indispensable for its pathogenesis. Besides translocated-intimin receptor (Tir), E. coli O157:H7 interacts with host cell surface receptors to promote intimate adhesion. This study showed that integrin β1 was increased in Caco-2 cells upon E. coli O157:H7 infection, while Caco-2 cells subjected to integrin β1 antibody blocking or CRISPR/Cas9 knockout had reduced bacterial attachment. Infection of E. coli O157:H7 inactivated focal adhesion kinase (FAK) and paxillin, increased focal adhesion (FA) and actin polymerization, and decreased cell migration in Caco-2 cells, which were rescued by integrin β1 antibody blocking or knockout. Pre-treatment with quercetin, known for its anti-oxidant and anti-inflammatory activity, reduced bacterial infection to Caco-2 cells, which might be partially via interfering integrin β1 and FAK association augmented by E. coli O157:H7. In addition, quercetin decreased FA formation induced by bacterial infection and recovered host cell motility. Taken together, data showed that E. coli O157:H7 interacts with integrin β1 to facilitate its adhesion to host cells. Quercetin inhibits bacterial infection possibly by blocking the interaction between E. coli O157:H7 and integrin β1. Collectively, these data indicate that quercetin provides an alternative antimicrobial to mitigate and control E. coli O157:H7 intestinal infection, and suggest potential broad benefits of quercetin and related polyphenols in fighting other enteric pathogen infections.

[Exploration of thrombus histological composition and clinical effect in mechanical thrombectomy of acute ischemic stroke]

Objective: To explore histological composition of thrombus and clinical effect in mechanical thrombectomy of acute ischemic stroke. Methods: From March 2017 to August 2017 at the Institutes of Biology and Medical Sciences of Soochow University, hematoxylin and eosin (HE) staining was used to quantitatively analyze the composition of thrombus in 58 cases with acute ischemic stroke. The differences in components of thrombus with different TOAST classifications were compared, meanwhile, clinical data such as surgical process and prognosis were also analyzed. Results: (1) Baseline data: the age of arteriosclerosis was significantly lower than that of cardiogenic (P<0.05). There was statistically significant differences in onset to admission between the two types of stroke of other undetermined etiology (SUE) and Cardioembolism (CE) (P<0.05). (2) Histological composition of thrombus: there were no significant differences in fibrin and red blood cells (RBC) between the two types of SUE and CE thrombus (P>0.05). There were more RBC in LAA thrombus and more fibrin in CE thrombus (P<0.05). (3) Intraoperative data: the time of admission to recanalization of type LAA was longer than that of type CE (P<0.05). (4) Prognosis: there was no significant difference in the good prognosis between the two types of SUE and CE (P>0.05). It is the same between the types of LAA and CE (P>0.05). Conclusions: LAA thrombus contains more RBC, and cardiogenic thrombus contains more fibrin. Cryptogenic thrombus has the same composition with cardioembolism. The results may help to choose appropriate recanalization technique in different TOAST stroke and have guiding significance for the secondary prevention of SUE stroke.

[Research progress of amphiregulin and its role in airway inflammatory disease]

Amphiregulin is a member of epidermal growth factor family, and is also one of the ligand of epidermal growth factor receptor, it participates in many physiological and pathological process by combining with EGFR. Researches have proved that AREG participates in asthma and airway inflammatory diseases caused by smoking and PM 2.5, and AREG plays an important role in the process of airway remodeling and inflammation. This paper mainly reviews the expression and function of AREG, and focus on it's research status in airway inflammatory disease.

The clinical effects of gonadotropin-releasing hormone agonists for the treatment of children patients with central precocious puberty

OBJECTIVE

We explored the clinical effect of gonadotropin-releasing hormone agonists for the treatment of children patients with central precocious puberty.

PATIENTS AND METHODS

From March 2012 to October 2015, 100 cases of children patients with central precocious puberty were enrolled in this study. Intramuscular injection of acetic acid triptorelin (50 to 100 pLg/kg) was made once every 4 weeks, and the treatment lasted for 4 months. Patients' bone age/height differentials (DBA/DCA), bone age (BA), growth velocity (GV) and predicted adult height (PAH) were determined before and after treatment (after 6, 12, 24, 36 months). Differences before and after treatment were analyzed. DBA/DCA, BA and PAH values 6, 12, 24, 36 months after treatment were significantly different compared with those before treatment.

RESULTS

Sexual development symptoms in children patients were significantly improved 4 months after treatment (p<0.05). All patients completed the treatment, without any adverse drug reaction or severe complication. After one course of treatment (4 months), patients' uterus and ovarian volumes shrank, FSH level peaked, and LH level was reduced, compared to those before treatment.

CONCLUSIONS

Acetate acid triptorelin is safe and reliable for treating central precocious puberty. We achieved the excellent clinical curative effect and were able to delay the growth rate in children patients. The predicted height and final height were improved.

Genetic interaction of purinergic P2X7 receptor and ER-α polymorphisms in susceptibility to osteoporosis in Chinese postmenopausal women

Osteoporosis (OP) is an increasing public health problem worldwide. Genetic factors are considered to be major contributors to the pathogenesis of OP. The aim of this study was to investigate the association of the purinergic P2X7 receptor (P2X7R) and estrogen receptor-α (ER-α) genes with OP risk, and the effect of the possible interaction between the two genes on predisposition to OP in Chinese postmenopausal women. A total of 596 subjects, including 350 OP patients and 246 controls, were recruited in this case-control study. Five functional single-nucleotide polymorphisms (SNPs) in the P2X7R gene (rs2393799, rs7958311, rs1718119, rs2230911, rs3751143) and two ER-α PvuII and XbaI polymorphisms were genotyped and analyzed. Single-gene variant analysis showed that the carriers of the CC genotype of P2X7R rs3751143 revealed an increased OP risk. Haplotype rs1718119G-rs2230911G-rs3751143C also appeared to be a significant 'risk' haplotype with OP. For the ER-α gene, no evidence of significant association of PvuII or XbaI polymorphism with OP risk was found. Moreover, there was a significant gene-gene interaction between P2X7R rs3751143 and ER-α PvuII; the cross-validation consistency was 10/10 and the testing accuracy was 0.5818 (P = 0.0107). A 1.67-fold-increased risk for OP was detected in individuals carrying the genotypes of AC or CC of rs3751143 and Pp or PP of PvuII compared to subjects with AA of rs3751143 and pp of PvuII. Our findings suggest an important association of the P2X7R rs3751143CC genotype and the rs1718119G-rs2230911G-rs3751143C haplotype with an increased OP risk. Also, the P2X7R rs3751143 and ER-α PvuII two-locus interaction confers a significantly high susceptibility to OP in Chinese postmenopausal women.

The effect of enriched environment across ages: A study of anhedonia and BDNF gene induction

Enriched environment treatment (EET) is a potential intervention for depression by inducing brain-derived neurotrophic factor (BDNF). However, its age dependency remains unclear. We recently found that EET during early-life development (ED) was effective in increasing exploratory activity and anti-despair behavior, particularly in promoter IV-driven BDNF deficient mice (KIV), with the largest BDNF protein induction in the hippocampus and frontal cortex. Here, we further determined age dependency of EET effects on anhedonia and promoter-specific BDNF transcription, by using the sucrose preference test and qRT-PCR. Wild-type (WT) and KIV mice received 2 months of EET during ED, young-adulthood and old-adulthood (0-2, 2-4 and 12-14 months, respectively). All KIV groups showed reduced sucrose preference, which EET equally reversed regardless of age. EET increased hippocampal BDNF mRNA levels for all ages and genotypes, but increased frontal cortex BDNF mRNA levels only in ED KIV and old WT mice. Transcription by promoters I and IV was age-dependent in the hippocampus of WT mice: more effective induction of exon IV or I during ED or old-adulthood, respectively. Transcription by almost all 9 promoters was age-specific in the frontal cortex, mostly observed in ED KIV mice. After discontinuance of EET, the EET effects on anti-anhedonia and BDNF transcription in both regions persisted only in ED KIV mice. These results suggested that EET was equally effective in reversing anhedonia and inducing hippocampal BDNF transcription, but was more effective during ED in inducing frontal cortex BDNF transcription and for lasting anti-anhedonic and BDNF effects particularly in promoter IV-BDNF deficiency.

[Association of α-actinin-3 gene polymorphism and muscle strength of postmenopausal women]

Objective: To explore the association between α-actinin-3 (ACTN3) polymorphism and muscle strength in postmenopausal women. Methods: Five hundred and ninety-eight postmenopausal women with an average of (62.9±7.0) years old in Dongcheng District of Beijing were included. The ACTN3 polymorphism including rs540874, rs618838 and rs2229456 were genotyped by Sequenom Mass Array to explore their associations with muscle strength. One hundred and sixty-three of them were trained with regular Tai chi movement while 271 were administered with elemental calcium 600 mg/d combined with Vitamin D 800 U/d or calcitriol 0.25 μg/d for 2 years. Association between changes of muscle strength and ACTN3 polymorphism were analyzed. Results: The rs540874 genotypes were found to be significantly associated with chair stand test[GG (9.02±3.85) s vs GA (9.27±4.14) s vs AA (9.68±5.00) s, P=0.015]. Right grip strength in women with G allele were likely to be higher compared with A allele, but it was not statistically significant (P=0.056). Multiple linear regression showed that the chair stand test of AA genotype was statistically longer than that of GG and GA genotype (β=2.639, 95% CI: 1.632-4.646, P=0.010). The associations between rs618838, rs2229456 genotypes and muscle strength of both lower and upper limbs were not significant (all P>0.05). In addition, muscle strength of lower limbs of patients with rs540874 genotyped with G allele, rs618838 genotyped with C allele and rs2229456 genotyped with A allele increased significantly after enhanced exercise and vitamin D supplementation (all P<0.05). Conclusions: The rs540874 polymorphism of ACTN3 gene was associated with the muscle function of lower limb in postmenopausal women. The improvement of muscle strength after intervention were possibly correlated with rs540874, rs618838 and rs2229456 polymorphisms.

Non-Dirac Chern insulators with large band gaps and spin-polarized edge states

Based on first-principles calculations and k·p models, we demonstrate that PbC/MnSe heterostructures are a non-Dirac type of Chern insulator with very large band gaps (244 meV) and exotically half-metallic edge states, providing the possibilities of realizing very robust, completely spin polarized, and dissipationless spintronic devices from the heterostructures. The achieved extraordinarily large nontrivial band gap can be ascribed to the contribution of the non-Dirac type electrons (composed of px and py) and the very strong atomic spin-orbit coupling (SOC) interaction of the heavy Pb element in the system. Surprisingly, the band structures are found to be sensitive to the different exchange and correlation functionals adopted in the first-principles calculations. Chern insulators with various mechanisms are acquired from them. These discoveries show that the predicted nontrivial topology in PbC/MnSe heterostructures is robust and can be observed in experiments at high temperatures. The system has great potential to have attractive applications in future spintronics.

Comparative Analysis of Diffusional Kurtosis Imaging, Diffusion Tensor Imaging, and Diffusion-Weighted Imaging in Grading and Assessing Cellular Proliferation of Meningiomas

BACKGROUND AND PURPOSE

An accurate evaluation of the World Health Organization grade and cellular proliferation is particularly important in meningiomas. Our aim was to prospectively evaluate and compare diffusional kurtosis imaging, DTI, and DWI metrics in determining the grade and cellular proliferation of meningiomas.

MATERIALS AND METHODS

Ninety-six consecutive patients with histopathologically confirmed meningiomas were included in this study. Mean kurtosis, radial kurtosis, axial kurtosis, fractional anisotropy, mean diffusivity, and ADC were semiautomatically obtained in the solid components of tumors. Each normalized diffusion value was compared between high-grade meningiomas and low-grade meningiomas using the Mann-Whitney U test. Receiver operating characteristic, multiple logistic regression, and Pearson correlation analysis were used for statistical evaluations.

RESULTS

Diffusional kurtosis imaging metrics (mean kurtosis, radial kurtosis, and axial kurtosis) were significantly higher in high-grade meningiomas than in low-grade meningiomas (P ≤ .001). Mean diffusivity and ADC were significantly lower in high-grade meningiomas than in low-grade meningiomas (P = .003 and .002). Mean kurtosis had significantly greater area the under curve values than mean diffusivity and fractional anisotropy in differentiating high-grade meningiomas from low-grade meningiomas (P = .038 and .002). Mean kurtosis was the only variable that could be used to independently differentiate high-grade meningiomas and low-grade meningiomas (P < .001). Significant correlations were found between the Ki-67 labeling index and kurtosis metrics (P < .001), as well as for mean diffusivity and ADC (P = .004, and .007).

CONCLUSIONS

Compared with other diffusion metrics, mean kurtosis may serve as an optimal parameter for evaluating and predicting the meningioma grade. Moreover, diffusion metrics may potentially reflect cellular proliferation.