P-type laser-doped WSe2/MoTe2 van der Waals heterostructure photodetector

Van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials are being studied extensively for their prospective applications in photodetectors. As the pristine WSe₂/MoTe₂ heterostructure is a type I (straddling gap) structure, it cannot be used as a photovoltaic device theoretically, although both WSe₂ and MoTe₂ have excellent photoelectric properties. The Fermi level of p-doped WSe₂ is close to its valence band. The p-doped WSe₂/MoTe₂ heterostructure can perform as a photovoltaic device because a built-in electric field appears at the interface between MoTe₂ and p-doped WSe₂. Here, a 633 nm laser was used for scanning the surface of WSe₂ in order to obtain the p-doped WSe₂. x-ray photoelectron spectroscopy (XPS) and electrical measurements verified that p-type doping in WSe₂ is produced through laser treatment. The p-type doping in WSe₂ includes substoichiometric WO_x and nonstoichiometric WSe_x. A photovoltaic device using p-doped WSe₂ and MoTe₂ was successfully fabricated. The band structure, light-matter reactions, and carrier-transport in the p-doped WSe₂/MoTe₂ heterojunction were analyzed. The results showed that this photodetector has an on/off ratio of ≈10⁴, dark current of ≈1 pA, and response time of 72 μs under the illumination of 633 nm laser at zero bias (V _ds = 0 V). The proposed p-doping method may provide a new approach to improve the performance of nanoscale optoelectronic devices.

MOTS-c accelerates bone fracture healing by stimulating osteogenesis of bone marrow mesenchymal stem cells via positively regulating FOXF1 to activate the TGF-β pathway

OBJECTIVE

To elucidate the function of MOTS-c in accelerating bone fracture healing by inducing BMSCs differentiation into osteoblasts, as well as its potential mechanism.

MATERIALS AND METHODS

Primary BMSCs were extracted from rats and induced for osteogenesis. The highest dose of MOTS-c that did not affect BMSCs proliferation was determined by CCK-8 assay. After 7-day osteogenesis, the relative levels of ALP, Bglap, and Runx2 in MOTS-c-treated BMSCs influenced by FOXF1 were examined. ALP staining and alizarin red S staining in BMSCs were performed as well. The interaction between FOXF1 and TGF-β was analyzed by ChIP assay. At last, rescue experiments were performed to uncover the role of FOXF1/TGF-β axis in MOTS-c-induced osteogenesis.

RESULTS

1 μM MOTS-c was the highest dose that did not affect BMSCs proliferation. MOTS-c treatment upregulated the relative levels of ALP, Bglap, and Runx2, and stimulated mineralization ability in BMSCs, which were attenuated by the silence of FOXF1. TGF-β was proved to interact with FOXF1, and its level was positively mediated by FOXF1. The silence of FOXF1 attenuated the accelerated osteogenesis and TGF-β upregulation in BMSCs because of MOTS-c induction, and these trends were further reversed by the overexpression of TGF-β.

CONCLUSIONS

MOTS-c treatment markedly induces osteogenesis in BMSCs. During MOTS-c-induced osteogenic progression, the upregulated FOXF1 triggers the activation of TGF-β pathway, thus accelerating bone fracture healing.

[Correlation between the expression of STOX1 in placenta of patients with early onset preeclampsia]

Objective: To investigate the relationship of STOX1expression and pathogenesis of early onset preeclampsia. Methods: 65 cases of preeclampsia women who delivered in Shanghai Pudong Hospital from October 2015 to June 2018, were recruited, which included 31 cases with early onset preeclampsia (early onset group, gestational week<34 weeks) and 34 patients with late onset preeclampsia (late onset group, gestational week ≥34 weeks). 34 cases women who received caesarean section because of pelvic structural deformities, breech presentation, macrosomia and social factors were included as the control group(gestational week ≥34 weeks) were selected as control group.The expression and localization of STOX1 mRNA and protein in placenta of three groups of maternal were evaluated by immunohistochemistry SP, RT-qPCR and Western blotting. Results: (1) The expression of STOX1 in placenta mainly distributed in the cytoplasm of placental syncytiotrophoblasts, cytotrophoblasts, vascular endothelial and mesenchymal cells, a few in the cell nucleus.The staining intensity of STOX1 in early onset group was significantly stronger than that in late onset group, the staining intensity of the late onset group was similar to that of the control group. The positive expression rates of STOX1protein in early onset group, late onset group and control group were 96.8%(30/31), 70.6%(24/34), 67.6%(23/34) respectively, which was higher in early onset group than that in late onset group(P=0.005). There was no statistical difference of STOX1 level between the late onset group and the control group(P=0.793). (2)Relative expression of STOX1 mRNA in early onset group, late onset group and control group were 0.054 3±0.003 5,0.037 5±0.000 7,0.035 2±0.000 4 respectively, which was significantly higher in early onset group than that in late onset group(P<0.05), while there was no statistical difference between the late onset group and the control group(P>0.05).(3)Relative expression level of STOX1 protein in early onset group, late onset group and control group were 0.78±0.04,0.59±0.020 and 0.54±0.018 respectively, which is higher in early onset group than that in late onset group(P<0.05). There was no statistical difference of STOX1 level between the late onset group and the control group(P>0.05). Conclusions: The pathogenesis of early onset and late onset preeclampsia may be different. Up-regulated expression of STOX1 in placenta may be associated with the pathogenesis of early onset preeclampsia.

[Expression and significance of STOX1 in villi and placenta at different stages of normal gestation]

Objective: To investigate the expression and significance of STOX1 in different stages of gestation villi and placenta. Methods: Totally 137 cases of normal villi and placenta of pregnant women were collected from the Department of Obstetrics of Shanghai Pudong Hospital from October 1(st) 2015 to February 28(th) 2018, including 64 cases of early pregnancy (early pregnancy group) which consists of 32 cases of 5-7(+6) weeks gestation (early pregnancy group A) and 32 cases of 8-11(+3) weeks gestation (early pregnancy group B), 28 cases of 14-26 weeks gestation(middle pregnancy group) and 45 cases of 37-41 weeks gestation (late pregnancy group). The expression and localization of STOX1 mRNA and protein in placenta were evaluated by RT-qPCR, Western blotting and immunohistochemistry. Results: (1)STOX1 was positively expressed in the cytotrophoblasts and syncytiotrophoblasts as well as interstitial and vascular endothelial cells of all groups. (2)STOX1 mRNA expression in each group was significantly different (P<0.05), the lowest was in the early pregnancy group A(0.007 8±0.000 4), which increased along with the progression of gestational age(P<0.05),and reached the highest level in the third trimester(0.064 4±0.001 3). (3)The protein level of STOX1 in different stages of normal pregnancy was 0.53±0.20 in early pregnancy group A;0.62±0.37 in early pregnancy group B;0.70±0.03 in middle pregnancy group and 0.81±0.04 in late pregnancy group respectively; which was positively related with the progression of gestational age (P<0.05). Conclusion: The expressions of STOX1 is gradually increasing along with the normal pregnancy progression, suggesting that it might be involved in proliferation, differentiation and infiltration and (or) apoptosis of trophoblast cells and the development of the placenta.

Neutralization of interleukin-9 ameliorates experimental stroke by repairing the blood-brain barrier via down-regulation of astrocyte-derived vascular endothelial growth factor-A

Astrocytes mediate the destruction of the blood-brain barrier (BBB) during ischemic stroke (IS). IL-9 is a pleiotropic cytokine that we previously found to be highly expressed in peripheral blood mononuclear cells from patients with IS, and the presence of IL-9 receptors on astrocytes has been reported in the literature. Here, we detected the effect of IL-9 on astrocytes using an anti-IL-9-neutralizing antibody to treat rats with experimental stroke. Supernatants from astrocytes treated with or without oxygen-glucose deprivation and/or IL-9 were incubated with bEnd.3 cell monolayers after blocking the IL-9 receptor on the endothelium. Immunofluorescence staining and Western blot analyses were conducted to observe the change in tight junction proteins (TJPs) in bEnd.3 cells as well as the level of VEGF-A and possible signal pathways in astrocytes. We also applied middle cerebral artery occlusion (MCAO) models to determine the effect of anti-IL-9-neutralizing antibodies on IS. As a result, astrocyte-conditioned medium treated with IL-9 aggravated the disruption of the BBB accomplished by the degradation of TJPs in endothelial cells. In addition, IL-9 increased the level of VEGF-A in astrocytes, and blocking the effect of VEGF-A reversed the breakdown of the BBB. In the MCAO model, anti-IL-9-neutralizing antibody reduced the infarct volume and BBB destruction. Mechanistically, the anti-IL-9-neutralizing antibody repaired the damaged TJPs (zonula occludens 1, occludin, and claudin-5) and induced a decrease in VEGF-A expression in ischemic lateral brain tissue. In contrast, a local injection of recombinant murine IL-9 to the brain resulted in a marked up-regulation of VEGF-A in the striatum. In conclusion, anti-IL-9-neutralizing antibody can reduce the severity of IS partially by alleviating the destruction of the BBB via down-regulation of astrocyte-derived VEGF-A. This finding suggests that targeting IL-9 or VEGF-A could provide a new direction for the treatment of IS.-Tan, S., Shan, Y., Lin, Y., Liao, S., Zhang, B., Zeng, Q., Wang, Y., Deng, Z., Chen, C., Hu, X., Peng, L., Qiu, W., Lu, Z. Neutralization of IL-9 ameliorates experimental stroke by repairing the blood-brain barrier via down-regulation of astrocyte-derived vascular endothelial growth factor-A.

The influence of non-breathing-related sleep fragmentation on cognitive function in patients with cerebral small vessel disease

BACKGROUND

Cognitive impairment in patients with cerebral small vessel disease (CSVD) is common, but the pathogenic mechanism is not well understood. The situation of non-breathing-related sleep fragmentation in CSVD patients and its influence on cognitive impairment is not clear. The aim of this study was to investigate the influence of non-breathing-related sleep fragmentation on cognitive function in patients with CSVD.

METHODS

A group of 89 CSVD patients without breathing-related sleep disorders in the Department of Neurology, Third Affiliated Hospital of Sun Yat-sen University was enrolled. The patients underwent magnetic resonance scan, polysomnography, cognitive function evaluation using Montreal Cognitive Assessment scale (MoCA), and Mini-Mental State Examination. The patients were assigned to study group (arousal index [ArI] ≥26.8/hour) or control group (ArI <26.8/hour) based on the average level of ArI (mean =26.8, SD =7.5) at night, and the cognitive function of the patients in the two groups was analyzed.

RESULTS

The total MoCA score, the subscale scores of visuospatial ability and delayed recall in the study group were significantly lower than that in the control group (P<0.05). The cognitive impairment measured by MoCA was positively related to ArI level and %N-3 sleep according to the results of logistic regression (P<0.05).

CONCLUSION

Non-breathing-related sleep fragmentation is associated with cognitive impairment in CSVD patients, especially executive function and delayed recall ability.

Targeted homing of CCR2-overexpressing mesenchymal stromal cells to ischemic brain enhances post-stroke recovery partially through PRDX4-mediated blood-brain barrier preservation

Rationale: Mesenchymal stromal cells (MSCs) are emerging as a novel therapeutic strategy for the acute ischemic stroke (AIS). However, the poor targeted migration and low engraftment in ischemic lesions restrict their treatment efficacy. The ischemic brain lesions express a specific chemokine profile, while cultured MSCs lack the set of corresponding receptors. Thus, we hypothesize that overexpression of certain chemokine receptor might help in MSCs homing and improve therapeutic efficacy. Methods: Using the middle cerebral artery occlusion (MCAO) model of ischemic stroke, we identified that CCL2 is one of the most highly expressed chemokines in the ipsilateral hemisphere. Then, we genetically transduced the corresponding receptor, CCR2 to the MSCs and quantified the cell retention of MSC^CCR2 compared to the MSC^dtomato control. Results: MSC^CCR2 exhibited significantly enhanced migration to the ischemic lesions and improved the neurological outcomes. Brain edema and blood-brain barrier (BBB) leakage levels were also found to be much lower in the MSC^CCR2-treated rats than the MSC^dtomato group. Moreover, this BBB protection led to reduced inflammation infiltration and reactive oxygen species (ROS) generation. Similar results were also confirmed using the in vitro BBB model. Furthermore, genome-wide RNA sequencing (RNA-seq) analysis revealed that peroxiredoxin4 (PRDX4) was highly expressed in MSCs, which mainly contributed to their antioxidant impacts on MCAO rats and oxygen-glucose deprivation (OGD)-treated endothelium. Conclusion: Taken together, this study suggests that overexpression of CCR2 on MSCs enhances their targeted migration to the ischemic hemisphere and improves the therapeutic outcomes, which is attributed to the PRDX4-mediated BBB preservation.

Cerebral small vessel disease: neuroimaging markers and clinical implication

Cerebral small vessel disease (CSVD) is a broad category of cerebrovascular diseases which primarily affect the perforating arterioles, capillaries and venules with multiple distinct etiologies. In spite of distinctive pathogenesis, CSVD shares similar neuroimaging markers, including recent small subcortical infarct, lacune of presumed vascular origin, white matter hyperintensity of presumed vascular origin, perivascular space and cerebral microbleeds. The radiological features of neuroimaging markers are indicative for etiological analysis. Furthermore, in sporadic arteriosclerotic pathogenesis associated CSVD, the total CSVD burden is a significant predictor for stroke events, global cognitive impairment, psychiatric disorders and later life quality. This review aims to summarize the radiological characteristics as well as the clinical implication of CSVD markers and neuroimaging interpretation for CSVD symptomatology.

Different Mechanisms of Two Subtypes of Perforating Artery Infarct in the Middle Cerebral Artery Territory: A High-Resolution Magnetic Resonance Imaging Study

Purpose: Perforating Artery Infarcts (PAIs) can be divided into two subtypes based on their etiologies: branch Atheromatous Disease (BAD) and Lacunar Infarct (LI). Recent studies have shown that while both subtypes can be caused by large artery lesions, the different mechanisms that underlie their development are not clear. This study was designed to use High-Resolution Magnetic Resonance Imaging (HRMRI) to explore the differences that contribute to the occurrence of these two subtypes in large artery lesions in the anterior circulation.

Methods: Fifty patients with an acute PAI in the anterior circulation were enrolled (32 BAD and 18 LI patients). The ipsilateral middle cerebral artery (MCA) was scanned with HRMRI to analyze the atherosclerosis plaques. Artery remodeling and plaque characteristics of MCA lesions were compared between the two subtypes.

Results: The rate of MCA lesions was significantly higher in BAD and substantially lower in LI (P = 0.033). LAs for the lumen areas in Bad, they were smaller than LI (P < 0.001), Additionally, the plaque area (P = 0.001) and plaque burden (P < 0.001) were superior in the BAD group. Most BAD patients displayed non-positive remodeling, while the great majority of LI patients showed positive remodeling (P < 0.001).

Conclusion: In the anterior circulation, a considerable amount of BAD and LI share similarities with atherosclerotic plaques in large arteries. BAD patients mainly showed relatively large and stable atherosclerotic plaques in large arteries, while LI patients mainly exhibited relatively small and unstable atherosclerotic plaques.

Clinical Trial Registration: This clinical trial is a retrospective study and therefore does not require registration.

Characteristics of paramedian pontine arteries disease and its association with hemoglobinA1c

Objectives

The association of branch atherosclerotic disease (BAD) and diabetes mellitus (DM) in the territory of posterior circulation is rarely discussed. Intracranial BAD was divided into two different types: paramedian pontine arteries (PPA) disease (PPD) and lenticulostriate arteries (LSA) disease. The goal of the study was to evaluate the clinical characteristics of PPD and its association with hemoglobinA1c (HbA1c) in China.

Materials and Methods

Radiologically confirmed PPD was defined as an isolated unilateral infarction extending to the ventral surface of the pons. Small deep cerebral infarctions are usually caused by two different pathological changes of arteries: BAD and lipohyalinotic degeneration (LD). We compared the vascular risk factors between BAD and LD in PPA territory. A total of 159 stroke patients were analyzed (PPD, n = 75; LD, n = 84). Patients with PPD were also categorized into two groups according to follow-up modified Rankin Scale (FmRS) scores. Logistic regression analyses were used for the evaluation of independent risk factors of PPD and prognosis.

Results

Comparison between PPD and LD revealed statistical significance in fasting glucose, HbA1c, estimated glomerular filtration rate (eGFR), and uric acid (p = .011, p = .005, p = .027, p = .018, respectively). Compared with LD, PPD was only related to HbA1c (p = .011) in logistic regression analysis. There were statistically significant differences between the two groups based on the stratification of FmRS scores in fasting glucose, HbA1c, homocysteine, eGFR, and the occurrence of DM. After multivariate analysis, only HbA1c was related with poor prognosis of PPD (p = .002).

Conclusions

The subtypes and prognosis of small deep brain infarcts are significantly influenced by elevated HbA1c level in PPA territory. DM might play an important role in the pathogenesis of PPD.

[Analysis of 17 cases underwent laparoscopic rectal cancer surgery with transanal natural orifice specimen extraction and resection]

Objective: To study the feasibility, safety and short-term efficacy of total laparoscopic rectal cancer surgery with transanal natural orifice specimen extraction and resection. Methods: From May 2014 to March 2016, 17 patients with rectal carcinoma were treated by total laparoscopic rectal cancer surgery with transanal natural orifice specimen extraction and resection. The clinical data of these patients was collected and retrospectively analyzed to assess the impact of the operation on postoperative recovery time and the incidence of complications. Results: All operations had been successfully accomplished without conversion to open surgery or conversional laparoscopic-assisted surgery . The median operative time was 105 minutes. The median blood loss was 35 ml. The median proximal and distal margin of tumor is 16 cm and 3.5 cm. The median number of lymph nodes harvest is 21, and the median first bowl movement is 43 hours. The hospitalization after operation is 8 days. No patient underwent abdomen hemorrhage or anastomotic leakage. Conclusion: Laparoscopic rectal cancer surgery with transanal natural orifice specimen extraction and resection appears to be feasible, safe and with promising efficacy for selected patients.

Abstract P4-06-09: Addition of a remote genetic counselor to the breast specialist's team improves clinical decision-making

Background: There is a shortage of trained genetic counselors (GC) and often long wait times for appointments, resulting in other specialists frequently ordering genetic testing. However, non-genetic specialists, including breast surgeons, find it difficult to stay current in genetics due to rapid advances in gene discovery, expanded panel offerings, and frequent changes to professional guidelines. We tested a novel model for hereditary cancer risk assessment where breast surgeons had “on demand” access to a remote laboratory-based genetic counselor for peer to peer consultation. In this study we sought to determine the impact this model has on breast surgeons' routinely ordering genetic testing including test identification, ordering patterns, and medical management.

Methods: An IRB approved multi-center prospective study involved 14 community-based breast cancer surgeons experienced with hereditary cancer risk assessment without a genetic counselor as part of their practice. Cases were all discussed with a remote Invitae GC to determine testing eligibility and selection. Physicians had the option to utilize remote GCs to discuss results or to refer to traditional genetic counseling services. Pre and post-test surveys were completed for each patient by the testing physician. To protect patient privacy, a unique case ID was used to link patient test data with identifying data.

Results: A total of 192 patients were evaluated with median age of 52. Risk assessment via BRCAPRO and the Hughes Risk model were performed on 98% of patients by the physicians. 65% of patients met NCCN guidelines for testing. Pathogenic mutations were found in 14% of patients. Breast surgeons changed their test selection 21% of the time after discussion with a GC. They called to discuss results in 47% of cases and medical management changes were incorporated in 15% of these cases based on discussion with a remote GC.

Conclusions: Remote GC provider support assisted physicians in facilitating customized test selection, aided in navigating challenging counseling cases, and impacted clinical management. This service may serve as a viable, effective model for 'on demand' genetic counseling support and may be a novel opportunity to expand genetic testing in a breast surgery setting.

Citation Format: Rosen B, O'Leary E, Shan Y, Pat W, Peter B. Addition of a remote genetic counselor to the breast specialist's team improves clinical decision-making [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-06-09.

Risk Factors and Clinical Manifestations of Juxtacortical Small Lesions: A Neuroimaging Study

Background and objective

White matter hyperintensities can be easily identified by brain imaging. Juxtacortical small lesion (JCSL) is a special type of white matter lesion, defined as no greater than 5 mm in diameter and adjacent to the cerebral cortex in location. We notice lately that JCSLs alone may be associated to various neurological symptoms. Here, we design the present study to determine the risk factors for JCSLs and their clinical manifestations in patients in our neurology clinic.

Methods

206 participants suffered from neurological disorders and completed magnetic resonance imaging (MRI) examinations were divided into two groups: patients with JCSLs and patients without lesions on MRI. Meanwhile, 129 age- and sex-matched healthy volunteers were also recruited. Laboratory examinations and the phenotypes and distributions of the symptoms of the three groups were compared.

Results

The serum levels of apoB and homocysteine (HCY) were independently related to the appearance of JCSLs and HCY level was also associated with the number of JCSLs. Patients with JCSLs might present with headache, insomnia, and/or anxiety/depression, which were related with the anatomical locations of the lesions.

Conclusion

These data suggest that JCSLs are symptomatic and might in result fromarteriole atherosclerosis, which should raise our attention.

High salt-induced activation and expression of inflammatory cytokines in cultured astrocytes

Salt (sodium chloride, NaCl) accumulation in the brain is associated with various diseases of central nervous system (CNS). Activation of astrocytes is an important manifestation of pathophysiological processes in the CNS. However, the direct impact of high salt (HS) environment on astrocytes is unclear. In the current study, we found that high salt treatment can induce activation of astrocytes both in vivo and in vitro, manifested as morphological alteration coupled with increased expression of glial fibrillary acidic protein (GFAP). Additionally, HS upregulated the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and vascular endothelial growth factor (VEGF); however, its effects on transforming growth factor-β (TGF-β) expression were not evident. Furthermore, HS treatment induced increased phosphorylation of signal transducer and activator transcription 3 (STAT 3). Inhibition of Janus kinase 2 (JAK 2) by specific pharmacological antagonists, AG490, attenuated the activation of JAK2/STAT3 pathway and induction of GFAP and other pro-inflammatory factors, respectively. The results suggest that the aforementioned multiple inflammatory cytokines and mediators that may be linked to the HS induced pathogenesis of CNS via the JAK2/STAT3 signaling pathways.

Serum 25-hydroxyvitamin D3 is associated with disease status in patients with neuromyelitis optica spectrum disorders in south China

Here, we investigated the relationship between serum 25-hydroxyvitamin D₃ (25[OH]D₃) levels and neuromyelitis optica spectrum disorder (NMOSD). Patients with NMOSD had lower 25(OH)D₃ levels than healthy people, with lower levels in patients in the acute phase than those in remission. An inverse correlation was found between 25(OH)D₃ and Expanded Disability Status Scale scores of patients during attacks. Higher serum 25(OH)D₃ levels were associated with greater amelioration of symptoms during corticosteroid therapy. These results indicate that decreased vitamin D may be involved in NMOSD pathogenesis, and that 25(OH)D₃ serum levels may reflect the severity of NMOSD in the acute phase.

Comparison of the Chinese ischemic stroke subclassification and Trial of Org 10172 in acute stroke treatment systems in minor stroke

Background

The underlying causes of minor stroke are difficult to assess. Here, we evaluate the reliability of the Chinese Ischemic Stroke Subclassification (CISS) system in patients with minor stroke, and compare it to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) system.

Methods

A total of 320 patients with minor stroke were retrospectively registered and categorized into different subgroups of the CISS and TOAST by two neurologists. Inter- and intra-rater agreement with the two systems were assessed with kappa statistics.

Results

The percentage of undetermined etiology (UE) cases in the CISS system was 77.3 % less than that in the TOAST system, which was statistically significant (P < 0.001). The percentage of large artery atherosclerosis (LAA) in the CISS system was 79.7 % more than that in the TOAST system, which was also statistically significant (P < 0.001). The kappa values for inter-examiner agreement were 0.898 (P = 0.031) and 0.732 (P = 0.022) for the CISS and TOAST systems, respectively. The intra-observer reliability indexes were moderate (0.569 for neurologist A, and 0.487 for neurologist B).

Conclusions

The CISS and TOAST systems are both reliable in classifying patients with minor stroke. CISS classified more patients into known etiologic categories without sacrificing reliability.

Anti-inflammatory effect of cholera toxin B subunit in experimental stroke

Background

Cholera toxin B subunit (CTB) has multifaceted immunoregulatory functions. Immunity plays an important role in the mechanism of stroke. However, little is known about whether CTB is beneficial for stroke.

Methods

CTB was administered intraperitoneally after ischemia to rats subjected to transient focal ischemia. Infarct volumes, body weight loss, and neurologic deficits were measured. Cytokines, microglia/macrophage activation, and transcriptional factors in the ischemic brain were tested. The mRNA expressions of IL-1β and TNF-α were tested in the microglia/macrophage isolated from the ischemic hemisphere. γδT cells, IL-17-producing γδT cells, Th17 cells, and regulatory T (Treg) cells in the ischemic brain were tested. γδT cells and Treg cells in the peripheral blood were also evaluated.

Results

CTB reduced infarct volumes, neurologic deficits, and body weight loss after ischemia. At 24 h after ischemia, CTB downregulated the levels of IL-1β, TNF-α, NF-kB p65, phosphorylated-ERK1/2, and microglia/macrophage activation and suppressed NF-kB binding activity, but did not affect the level of ERK1/2. The mRNA expressions of IL-1β and TNF-α in the microglia/macrophage isolated from the ischemic hemisphere were suppressed after CTB therapy. In the ischemic hemisphere, CTB treatment reduced the levels of γδT cells, IL-17-producing γδT cells, and IL-17 at both 24 and 72 h after ischemia, while Th17 cells were not affected. After CTB treatment, the levels of Treg cells, TGF-β, and IL-10 remained unchanged at 24 h and upregulated at 72 h after ischemia. Inactivation of Treg cells using anti-CD25 attenuated the increase of TGF-β and IL-10 induced by CTB at 72 h after ischemia. In the peripheral blood, CTB increased Treg cells and suppressed γδT cells at 24 h after ischemia. And then at 72 h after ischemia, it increased Treg cells but did not impact γδT cells. CTB had no effect on cytokines, transcription factors, infiltrating γδT cells, and Treg cells in the brain of shams. In the peripheral blood of shams, CTB increased Treg cells at both 24 and 72 h, while it did not affect γδT cells.

Conclusions

CTB decreased neurologic impairment and tissue injury after cerebral ischemia via its immunomodulatory functions, including inhibiting microglia/macrophage activation, suppressing γδT cells, and inducing production of Treg cells, thus regulating the secretion of related cytokines. Suppression of NF-kB and ERK1/2 pathways is involved in the neuroprotective mechanism of CTB.

eEF-2 kinase is a critical regulator of Warburg effect through controlling PP2A-A synthesis

Cancer cells predominantly metabolize glucose by glycolysis to produce energy in order to meet their metabolic requirement, a phenomenon known as Warburg effect. Although Warburg effect is considered a peculiarity critical for survival and proliferation of cancer cells, the regulatory mechanisms behind this phenomenon remain incompletely understood. We report here that eukaryotic elongation factor-2 kinase (eEF-2K), a negative regulator of protein synthesis, has a critical role in promoting glycolysis in cancer cells. We showed that deficiency in eEF-2K significantly reduced the uptake of glucose and decreased the productions of lactate and adenosine triphosphate in tumor cells and in the Ras-transformed mouse embryonic fibroblasts. We further demonstrated that the promotive effect of eEF-2K on glycolysis resulted from the kinase-mediated restriction of synthesis of the protein phosphatase 2A-A (PP2A-A), a key factor that facilitates the ubiquitin-proteasomal degradation of c-Myc protein, as knockdown of eEF-2K expression led to a significant increase in PP2A-A protein synthesis and remarkable downregulation of c-Myc and pyruvate kinase M2 isoform, the key glycolytic enzyme transcriptionally activated by c-Myc. In addition, depletion of eEF-2K reduced the ability of the transformed cells to proliferate and enhanced the sensitivity of tumor cells to chemotherapy both in vitro and in vivo. These results, which uncover a role of the eEF-2K-mediated control of PP2A-A in tumor cell glycolysis, provide new insights into the regulation of the Warburg effect.