Search

Motor neuron disease (MND), including amyotrophic lateral sclerosis, spinal muscular atrophy and others, involved the upper or lower motor neurons selective loss, is characterized by neurodegeneration and neuroinflammation, in conjunction with microglia. We summarized that pathways and key mediators are associated with microglia, such as fractalkine signaling, purinergic signaling, NF-κB signaling, p38 MAPK signaling, TREM2-APOE signaling, ROCK signaling, C1q signaling, and Ion channel, which are involved in the activation, proliferation, and inflammation of microglia. This review aims to identify the microglia-related molecular target and explore potential treatment strategies for MND based on that target.

Autonomous Vehicles (AVs) have great potential and can improve transportation efficiency and safety through minimal manual intervention and optimized traffic control systems. Advances in artificial intelligence and real-time data processing technology have promoted the development of practical AVs. AV manufacturers are trying to understand the potential factors that may affect consumers' acceptance of autonomous vehicles. However, there is very little research on autonomous vehicles and consumers. In order to understand these factors, this research will use UTAUT 2, as a research framework to predict consumer intentions and behaviors. This research will first review the literature, invite experts to define and evaluate appropriate criteria and dimensions, and use the ANFIS is used to derive the decision rules, and the weights of the corresponding rules are compared. The resulting analysis can be used as a basis for predicting consumer acceptance of AVs in the future.

The oil and gas extraction industry is an energy-intensive and high CO2 emission sector in China. This study estimates the cost-effective CO2 emission reduction potentials until 2050 by classifying key low-carbon technology bundles and investigating the energy efficiency, market penetration rate, and emission reduction cost of each technology bundle. A bottom-up technical evaluation model is established to give a comprehensive perspective to the Chinese oil and gas extraction industry and policymakers about the emission reduction potential and its associated cost. Results show that the carbon emission reduction potential in the Chinese oil and gas extraction industry in 2050 can reach 16.71 million tons in the case of all low-carbon technologies available and that the decrease rate can be as high as 14.3%. The contributions of emission reductions are mainly the improvement of energy efficiency, the transformation of production process, and the utilization of new energy sources. Most low-carbon technologies are cost-effective, with an average annual cost savings of 71.43 billion RMB. Nonetheless, the diffusions of low-carbon technologies are still significantly affected by energy price volatility and firms' expectations of future investment risk.

To study the effect of subliminal vibration to recover young drivers' attention, fifteen subjects were selected to carry out simulated driving experiments. Focusing on driving (single driving), distracted driving, dominant vibration warning driving and subliminal vibration warning driving were carried out respectively. ECG signal and driving performance of subjects were recorded under these four kinds of driving conditions. ECG signal was analyzed using MATLAB.The results indicate that compared with ECG data of single driving the increasing amplitude of subliminal vibration warning is lower than those of the other warming methods, and the driving performance of subliminal vibration warning is better than those of other warning methods. Therefore, subliminal vibration warning can effectively recover the driver's attention. It also provides a reference for the future research on the road traffic safety system.

Accelerate the corrosion of the nanometer organic coating by design salt spray test. Research the corrosion resistance of the nanometer organic coating in grotto environment by EIS. The results show that prolong time of the salt spray test, the coating surface become to coarseness, the colour occur slight change, but no blistering and flake away. The Rc and Rt descend, every ten days the corrosion rate of coating augment decuple, at forty days is 3.14μm/a and the steel is not corrosion. The nanometer organic coating behave good protection ability and corrosion resistance in the grotto environment.

Aiming to the corrosion prevention of 16MnR steel surface in the light aggregate concrete, the paper applies a kind of corrosion prevention system composed of layered coating. It utilizes measurement methods such as field emission scanning electron microscopy and energy disperse spectroscopy to study the corrosion and change process of this kind of coating system in the surface of 16MnR steel in the environment of light aggregate concrete and make the evaluation on its effect of corrosion protection. The experiment result indicates that due to its mechanical masking function, the layered coating system can effectively restrain immersion of the corrosive medium in early corrosion period so as to protect the metallic matrix. With the deepening of the corrosion, the nanometer Zn particle has the function of cathodic protection on the metallic matrix, effectively enhancing the comprehensive corrosion protection ability of the coating system.

One’s head pose can be estimated using face images. The hidden manifold of head pose in the high dimensional space can be successfully embedded into a 2 dimensional space using Kernel Principal Component Analysis (KPCA). A pose curve is gotten using KPCA train samples and new pose image is projected onto this curve. The pose angle can be estimated using interpolation method. The disadvantage of traditional linear method is conquered by using 2-D KPCA and the experimental results that the method is effective to estimate head poses. The kernel functions effects on estimation accuracy are also discussed.

Daqing Wuzhan gas field is a deformable low permeability gas filed. Based on the lab study of changing law of porosity and permeability with confining pressure, a numerical simulation model of deformable low permeability gas reservoir is established and is solved by using IMPES method. Comparing with the result of eclipse shows the method is valid. Field example shows the dynamic geological reserves of Wuzhan gas field is low and the new wells should be drilled at the area where there is production potential and larger effective thickness. Comparison of results obtained from different models with field data shows the result considering medium deformation is more reasonable.

This study deals with the optimization control of a single-phase brushless DC motor (BLDCM) with Hall sensor. A simple modeling method with feasible parameter identification is adopted to meet characteristics of single- phase BLDCM. With the linear Hall sensor feedback, the advantages of current-mode control scheme and soft- commutation scheme are proposed to achieve maximum efficiency over the entire speed range. This thesis also develops a low-cost and high efficiency control for single-phase BLDCM. The hardware test platform has been constructed on a single-chip Field Programmable Gate Array (FPGA) of Cyclone II Family of Altera to verify the performance and feasibility of the proposed optimization control strategies. When using the control scheme with Hall sensor, experimental results show that there are at least a 10% improvement for average value of dc-link current, a 10% improvement for RMS value of phase current and a 40% improvement for peak value of phase current.

The aim of this study was to investigate the expression and prognostic significance of NEDD9 in pancreatic ductal adenocarcinoma (PDA). Expressional levels of NEDD9 mRNA and protein in paired pancreatic cancer lesions and adjacent noncancerous tissues were examined by quantitative real-time PCR and western blotting. NEDD9 expression was analyzed by immunohistochemistry in 106 patients with PDA. The correlations between NEDD9 immunostaining levels and clinicopathologic factors, as well as the follow-up data of patients, were analyzed statistically. NEDD9 protein and mRNA levels were elevated in pancreatic carcinoma lesions compared with the paired adjacent noncancerous tissues. A high level of expression of NEDD9 was significantly correlated with clinical staging (P < 0.001), lymph node metastasis (P < 0.001), and histological differentiation (P < 0.001). Patients with a higher NEDD9 expression had a significantly shorter survival time than those patients with lower NEDD9 expression. The multivariate analysis revealed that NEDD9 could serve as an independent factor of poor prognosis. Our finding indicates that NEDD9 could be used as prognostic molecular marker and therapeutic target for PDA.

In view of the shortcoming of driver state detection system which may take turn behavior as driver distraction, a new method to recognize turn behavior was proposed based on video images analysis. The driver hands position in different driving behavior were analyzed and we found that the position of driver’s hands changed more violent when in turning than in other driving behavior. So we may use standard deviation of driver hands position to recognize driver turn behavior. In order to improve the hands locating speed the Particle Filtering was used to track the driver hands. And experiments resulted that the recognition algorithm can identify the driver's turn behavior.

Manganese-activated willemite (α-Zn 2 − x Mn x SiO 4 ; x = 0.05–0.20) phosphor thin films with bright green light emission were deposited on silicon wafers by a sol–gel process. Zinc chloride, tetraethylorthosilicate, and manganese chloride were employed as precursors. The sol–gel transition, crystallization process and photoluminescence of processed films were investigated. The level of manganese doping did not greatly affect the crystallinity, but did affect the gelation rate and luminescence of films. X-ray diffraction and infrared spectrum studies revealed that single-phase willemite started to crystallize at around 600 °C. After thermal annealing at 600°–1200 °C, the crystallinity of films increased with increasing heating temperature and thickness of films. The emission intensity of the film was strongly related to the crystallinity and deposition conditions. Controlling the dopant content, number of coating layers and annealing temperature could significantly enhance the brightness of the green emission. The luminescence properties of α-Zn 2 SiO 4 :Mn films are characterized by fluorescence spectra and decay lifetime measurements.

Zn、Al alloy coatings were prepared by high velocity arc spraying technology on 16MnR steel substrates, With the design salt spray test, Study on the corrosion resistance of the Zn、Al alloy coating in the grotto environment. The porosity of the metal coating and the compact of the corrosion are infection on the corrosion resistance of the coating. Al coating and Zn/Al(300/100) coating corrosion resistance better than others on 16MnR steel.

The properties of Ni-B composite coating and corrosion resistance on the surface of 45 steel were investigated in this paper. An optimal component of plating solution was determined by the measurements of the stability of different component of plating solution and coating hardness as well as corrosion rate under different heat treatment temperature. The experimental results indicated that, when the heat treatment temperature was 300°C, the coating hardness reached 257HV and the corrosion rate was less than 0.15g•m-1•h-1, therefore the coating possessed high corrosion resistance.

The Brushless Direct Current Motor (BLDCM) is in nature of high power density, high reliability and easy control etc, growing with the development of microcomputers, new power electronic devices, control theories and low cost rare earth permanent magnet material. The applications of a new permanent magnet material are described in this paper,such as in manufacture of parts of stereo,automobile devices,medical instruments and computer hardware, etc.Besides,the paper also discusses the prospect of its development and the problems in its production.Aiming at the BLDCM with a Hall rotor position sensor, a motor drive controller is designed by pure hardware approach. In this paper, a simple design procedures is described that can be implemented to decrease the material cost of a BLDCM often found in domestic appliances and automotive applications. According to the experiment’s result, this controller has the advantages of easy debugging, high anti-interference ability, larger driving power, low volume and low cost in large scale production.

The Brushless Direct Current Motor (BLDCM) has been researched by many scholars because of its simple structure, high power density, high reliability and easy control. In this paper, a driver based on the system on a programmable chip (SOPC) is designed to implement adjustable subdivision. For SPWM, SVPWM frequency conversion control Direct Digital Synthesizer(DDS) is introduced, DDS Intellectual Property (IP) core is designed for motor control of frequency conversion. This driving system can solve the high subdivision problem, increase the driving torque and angle resolution, and smooth the motor angle. Employing the bottom-top design method, the circuit was described by the VHDL language, synthesized by integrated environment, and simulated by Modelsim in both behavior level and gate level through the PLI interface. According to experiment’s result, this driver has the advantages of easy debugging, high anti-interference ability, larger driving power, low volume and low cost in large scale production.

Homogeneous and nanocrystalline manganese-doped zinc orthosilicate (Zn 2 SiO 4 :Mn) phosphor powders were prepared using a sol–gel process by controlling the hydrolysis of silicon alkoxide and zinc chloride precursors. The Mn dopant content influenced the gelation rate, homogeneity, degree of agglomeration, and luminescence of powders. Mn-doped xerogel powders were amorphous and crystallized into pure willemite (α-Zn 2 SiO 4 ) structure when heated to 600 °C. After heating at 800–1000 °C, the crystallite sizes of Zn 2− x Mn x SiO 4 phosphor powders were around 15–32 nm at an Mn doping level of x = 0.2–20 mol%. The resulting powder phosphors exhibited prominent photoluminescence emission peaks centered at 520–529 nm, depending on the doping content. The intensity of the green emission was strongly related to the dopant content and improved crystallinity. Furthermore, reducing the specific surface area and pore volume further enhanced the luminous efficiency of willemite powders. The sol–gel transition, crystallinity, microstructure, and luminescent property of phosphor powders were investigated.

Additional to the basic Nagel–Schreckenberg model for single-lane traffic flow, we consider the effect of the velocity-difference between two successive vehicles on the randomization of the latter one. This modification improves the transit capacity of the model, which results in a much higher simulated flux. Moreover, in a circular road, this model simulates an abnormal hysteresis effect. The characteristic shape of hysteresis curves may shed some light on the distinguish of synchronized flow and jams.

HoxA10 is a homeodomain transcription factor that is frequently overexpressed in human acute myeloid leukemia. In murine bone marrow transplantation studies, HoxA10 overexpression induces a myeloproliferative disorder with accumulation of mature phagocytes in the peripheral blood and tissues. Over time, differentiation block develops in these animals, resulting in acute myeloid leukemia. In immature myeloid cells, HoxA10 represses transcription of some genes that confer the mature phagocyte phenotype. Therefore, overexpressed HoxA10 blocks differentiation by repressing myeloid-specific gene transcription in differentiating myeloid cells. In contrast, target genes involved in myeloproliferation due to HoxA10 overexpression have not been identified. To identify such genes, we screened a CpG island microarray with HoxA10 co-immunoprecipitating chromatin. We identified the DUSP4 gene, which encodes mitogen-activated protein kinase phosphatase 2 (Mkp2), as a HoxA10 target gene. We analyzed the DUSP4 5'-flank and identified two proximal-promoter cis elements that are activated by HoxA10. We find that DUSP4 transcription and Mkp2 expression decrease during normal myelopoiesis. However, this down-regulation is impaired in myeloid cells overexpressing HoxA10. In hematopoietic cells, c-Jun N-terminal kinases (Jnk) are the preferred substrates for Mkp2. Therefore, Mkp2 inhibits apoptosis by dephosphorylating (inactivating) Jnk. Consistent with this, HoxA10 overexpression decreases apoptosis in differentiating myeloid cells. Therefore, our studies identify a mechanism by which overexpressed HoxA10 contributes to inappropriate cell survival during myelopoiesis.

To investigate the method of separation of culture of bone microvascular endothelial cells (BMECs) of human femoral head in vitro.From October 2013 to January 2014,15 femoral heads without pathologic change from patients resected during hip replacement were selected involving 2 males and 13 females with a mean age of 71.2 years old ranging from 38 to 92. Cancellous bone in femoral head was bited into broken bone grain and transfered into medium in aseptic contidion. Cells were isolated by the methods of enzymic digestion and density gradient centrifugation,purified by differiential attachment. The characteristics of cells was observed by inverted microscope. vWF and CD31 immunofluorescence analysis was applied for identification of cells.The number of cells was positively correlated with patients' age after 24 hours in primary culture. The older patients had the less cells numbered. After 4 to 5 days' culture, primary cells appeared short spindle,polygon shaped and cobblestone-like morphology. After 7 to 10 days' culture, primary cells proliferated densely, became fusion, arranged in swirl, and contact inhibition appeared significantly. Immunofluorescence staining revealed the cells were 100% positive for vWF and CD31, and it showed that the cultured cells were BMECs.It was a simple, steady, effective method with good reproducibility, by which highly purified human BMECs can be obtained.

The homeodomain proteins, HoxA10 and Pbx1a, interact with negative cis elements to repress gene transcription in undifferentiated myeloid cells. The CYBB and NCF2 genes, which encode the gp91PHOX and p67PHOX proteins, are two such HoxA10-Pbx1a target genes. In previous studies, we found that HoxA10-Pbx1a represses transcription of these genes by two mechanisms: competition for DNA binding with transcriptional activators and endogenous repression activity. In these studies, we identify a novel molecular mechanism of endogenous transcriptional repression by HoxA10-Pbx1a. Endogenous repression activity of other Hox-Pbx1a complexes requires recruitment of transcriptional co-repressor proteins by Pbx1a. In contrast, our investigations have determined that HoxA10 has Pbx1a-independent endogenous repression activity. We find that this transcriptional repression activity is abrogated by histone deacetylase inhibitors, suggesting involvement of co-repressor proteins. Consistent with this, we identify HoxA10 amino acids 224-249 as a Pbx1-independent repression domain, which interacts with histone deacetylase 2. We have determined that this HoxA10 domain is not conserved with other Abd Hox proteins, although homology exists with other transcription factors and co-repressors. Understanding the roles different Hox proteins play in myeloid differentiation is a challenging problem. Our results suggest that insight into this problem can be obtained from biochemical characterization of the various molecular mechanisms of Hox protein function.

The homeodomain protein HoxA10 interacts with negative cis elements to repress gene transcription in undifferentiated myeloid cells. The CYBB and NCF2 genes, which encode the gp91(PHOX) and p67(PHOX) proteins, are two such HoxA10 target genes. During interferon gamma-induced myeloid differentiation, tyrosine phosphorylation decreases HoxA10 DNA binding affinity and transcriptional repression. Therefore, decreased HoxA10 repression contributes to increased CYBB and NCF2 transcription in differentiating myeloid cells. The current studies investigate modulation of HoxA10 repression activity during myelopoiesis. We determine that phosphorylation of tyrosine residues in the conserved homeodomain decreases HoxA10-DNA binding. We also determine that interaction of the homeodomain phosphotyrosine residues with an adjacent domain in the HoxA10 protein is necessary for decreased DNA binding affinity. Since SHP1 protein-tyrosine phosphatase antagonizes myeloid differentiation and decreases CYBB and NCF2 transcription, we investigated the influence of SHP1-protein-tyrosine phosphatase (PTP) on HoxA10 tyrosine phosphorylation. We find that SHP1-PTP activity increases HoxA10 target gene repression in undifferentiated myeloid cells. Consistent with this, SHP1-PTP interacts with HoxA10 and decreases homeodomain-tyrosine phosphorylation. These investigations suggest that SHP1-PTP activity, in undifferentiated myeloid cells, influences HoxA10 repression of myeloid-specific genes. Therefore, increased HoxA10 repression of myeloid gene transcription is a molecular mechanism for SHP1 inhibition of myeloid differentiation.

In this paper we study Toeplitz operators on Dirichlet spaces and describe the boundedness and compactness of Toeplitz operators on Dirichlet spaces. Meanwhile, we give density theorems for Toeplitz operators on Dirichlet spaces

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies in humans, and its prognosis is generally poor even after surgery. Many advances have been made to understand the pathogenesis of PDA; however, the molecular mechanisms that lead to pancreatic carcinogenesis are still not clearly understood. The aims of this study were to investigate the relationship between DLC-1 methylation status and clinicopathological characteristics of PDA patients and evaluate the role of DLC-1 methylation status in PDA. The expression of DLC-1 mRNA in PDA tissues was analyzed by real-time PCR. The methylation status of DLC-1 was analyzed by methylation-specific polymerase chain reaction (MSP). Furthermore, we determined the prognostic importance of DLC-1 methylation status in PDA patients. Our results showed that the expression level of DLC-1 mRNA in PDA tissues was lower than that in non-cancerous tissues. The rate of DLC-1 promoter methylation was significantly higher in PDA tissues than in adjacent non-cancerous tissues (p

To calculate the electromagnetic parameter of permanent magnet reciprocating generator accurately, based on two-dimensional finite element method, in the condition of considering the end effect, the static magnetic field model is created. The method which electromagnetic parameters in a running period are calculated with is proposed, the no-load electromotive force, synchronous reactance and the no-load, loaded electromagnetic force are solved. The simulation and experiment results indicated that the error is small, and the method avoided the problem that transient analysis spending too much time.

In order to more accurately analysis the starting process of medium-sized motors with high-voltage, the dynamic model of three-phase induction motor was established. The starting characteristics of the new medium-sized motors with high-voltage were calculated, based on this, the stator and rotor temperature rise was calculated, combined with the heat dissipation mode the amount of time for motors to reach thermal equilibrium was calculated. Compared with the steady-state characteristic curve, the dynamic characteristic curve is much closer to the practical situation and the temperature rise is in accord with the experimental value.

The objective of this study was to retrospectively evaluate stability of mandibular advancement after bilateral sagittal split osteotomies were performed. Three different fixation and immobilization protocols were examined. Thirty-three patients were evaluated with preoperative, immediate postoperative, and long-term (mean, 13 months) lateral cephalometric radiographs. The patients were divided into three groups: group 1 (n = 10) had nonrigid internal fixation and 6 weeks of maxillomandibular fixation, group 2 (n = 12) had rigid internal fixation and immediate postoperative function, and group 3 (n = 11) had rigid internal fixation with maxillomandibular fixation for a mean of 14 days. Group 3 had the least amount of sagittal and vertical relapse. Differences in sagittal relapse were statistically significant between groups 1 and 3. Group 2 demonstrated greater sagittal relapse than did group 3, although the result was not statistically significant. This study suggests that the use of rigid internal fixation with a period of maxillomandibular fixation appears to be more stable than nonrigid internal fixation with maxillomandibular fixation or rigid internal fixation without maxillomandibular fixation.

To observe the results of total hip replacement with collum femoris preserving for the treatment of advanced stage of femoral head necrosis of youth.From August 2002 to November 2009, 21 patients (28 hips) with advanced stage of femoral head necrosis were treated with total hip replacement with collum femoris preserving. Sixteen males (22 hips) and 5 females (6 hips) with an average age of 36 years (range from 26 to 51 years) were included. All patients were evaluated clinically using Harris score, the prosthesis components were assessed for position, loosening, bone resorption and other conditions with radiographs.Nineteen patients (26 hip) were followed up for mean 5 years and 7 months (ranging 5 years and 3 months to 7 years and 1 month), 2 patients were missed. The average Harris score increased from the preoperative average 48.5 to 90.2. The leg-length discrepancy (the difference was less than 2 cm) occurred in 3 cases. No thigh pain and revision.Total hip arthroplasty with collum femoris preserving is one of the best choices for the treatment of advanced stage of femoral head necrosis of young patients with good midterm outcome.

We report thermoelectric characterization of Bi2-xSbxTe3 (x = 0.5, 1.0, and 1.5) synthesized by a solvothermal method using DMF as solvent. For Bi2Te3, the size of the edge and thickness of the hexagonal nanoplatelets are 200-250 nm and 20-25 nm, respectively. Bi2Te3 nanosheets appear to grow epitaxially from the surface of the Te tubes, which forms in the first step and acts as the template for the formation of the nanostructure. Upon doping with Sb, the morphology of Bi1.5Sb0.5Te3 changes to a cluster of nanoparticles with the size of ~100 nm. The morphology of Bi0.5Sb1.5Te3 consists of mainly nanoplatelets with a size of less than 100 nm and warped nanosheets growing along the Te tube. The nominal composition of Bi2Te3 mats containing sheet-tubes shows a negative thermopower of ca. -94 muV/K at 280 K, whereas Bi0.5Sb1.5Te3 shows a positive thermopower of ca. 200 muV/K at 280 K.

Transcription of the ITGB3 gene, which encodes beta3 integrin, increases during myeloid differentiation. alphavbeta3 integrin mediates adhesion to fibronectin or vitronectin and regulates various aspects of the inflammatory response in mature phagocytes. In these studies, we found that the homeodomain transcription factor HoxA10 interacted with a specific ITGB3 cis element and activated transcription of this gene during myeloid differentiation. We also found that increased fibronectin adhesion in differentiating myeloid cells was dependent upon this HoxA10-induced increase in beta3 integrin expression. We determined that activation of ITGB3 transcription required a HoxA10 domain that was not identical to the "hexapeptide" that mediates interaction of Hox and Pbx proteins. This activation domain was also not identical to a previously identified HoxA10 repression domain that mediates interaction with transcriptional co-repressors. Instead, this HoxA10 activation domain had homology to "PQ" protein-protein interaction domains that have been described previously in other transcription factors. Consistent with this, we found that the HoxA10 PQ-like domain recruited the CREB-binding protein (CBP) to the ITGB3 promoter. This was associated with an increase in local histone acetylation in vivo. In immature myeloid cells, we previously determined that HoxA10 repressed transcription of the CYBB and NCF2 genes, which encode the phagocyte oxidase proteins gp91(PHOX) and p67(PHOX), respectively. Therefore, our studies indicated that HoxA10 either activates or represses gene transcription at various points during myelopoiesis. Our studies also suggested that HoxA10 is a bifunctional protein that is involved in dynamic regulation of multiple aspects of phagocyte phenotype and function.

In this brief report, we study the synchronization of growing scale-free networks. An asymmetrical age-based coupling method is proposed with only one free parameter $\alpha$. Although the coupling matrix is asymmetric, our coupling method could guarantee that all the eigenvalues are non-negative reals. The eigneratio R will approach to 1 in the large limit of $\alpha$., Comment: 3 pages, 1 figure

p67phox and gp91phox are components of the phagocyte-specific respiratory burst oxidase that are encoded by the NCF2 and CYBB genes, respectively. These genes are transcribed exclusively in myeloid cells that have differentiated beyond the promyelocyte stage. In mature phagocytes, NCF2 and CYBB transcription continues until cell death and further increases in response to IFN-γ and other inflammatory mediators. Because p67phox and gp91phox expression profiles are similar, we hypothesize that common transcription factors interact with homologous cis elements in the CYBB and NCF2 genes to coordinate transcription. Previously, we identified a negative CYBB promoter cis element that is repressed by the homeodomain transcription factor HoxA10. We found that transcriptional repression requires HoxA10-dependent recruitment of histone deacetylase activity to the CYBB cis element. In response to IFN-γ, phosphorylation of two tyrosine residues in the HoxA10 homeodomain decreases binding to CYBB promoter, thereby abrogating HoxA10-mediated repression. In the current studies, we investigate the possibility that HoxA10 similarly represses NCF2 transcription. We identify a sequence in the NCF2 promoter that is homologous to the HoxA10-binding CYBB cis element. We find that this NCF2 promoter sequence functions as a negative cis element that is repressed by HoxA10 in a tyrosine phosphorylation and histone deacetylase-dependent manner. Our results suggest that cytokine-stimulated pathways regulate HoxA10-mediated repression of the CYBB and NCF2 genes in differentiating myeloid cells and in mature phagocytes during the inflammatory response. Because p67phox and gp91phox are rate-limiting components for respiratory burst activity, our studies may identify rational therapeutic targets to modulate free radical generation in pathological conditions.

The CYBB gene encodes gp91Phox; a component of the phagocyte respiratory burst oxidase. CYBB transcription is restricted to myeloid cells differentiated beyond the promyelocyte stage. In undifferentiated myeloid cells, the homeodomain (HD) transcription factor HoxA10 represses CYBB transcription via a cis element in the proximal promoter. During myelopoiesis, phosphorylation of conserved tyrosine residues in the HD decreases HoxA10 binding to this CYBB cis element. In the current studies, we found HoxA9 activates CYBB transcription in differentiated myeloid cells via the same cis element. We find HoxA9-mediated CYBB-transcription requires Pbx1 but is inhibited by Meis1. Additionally, phosphorylation of the conserved HD tyrosines increases HoxA9 binding to the CYBB promoter. The HOXA9 gene is involved in leukemia-associated translocations with the gene encoding Nup98, a nucleopore protein. We find expression of a Nup98-hoxA9 fusion protein blocks HoxA9-induced CYBB transcription in differentiating myeloid cells. In comparison to HoxA9, Nup98-hoxA9 has greater binding affinity for the CYBB cis element, but binding is not altered by HD tyrosine phosphorylation. Therefore, these studies identify CYBB as a common target gene repressed by HoxA10 and activated by HoxA9. These studies also suggest overexpression of Meis1 or Nup98-hoxA9 represses myeloid-specific gene transcription, thereby contributing to differentiation block in leukemogenesis.

Deficiency of the interferon consensus sequence-binding protein (ICSBP) is associated with increased myeloid cell proliferation in response to hematopoietic cytokines. However, previously identified ICSBP target genes do not indicate a mechanism for this "cytokine hypersensitivity." In these studies, we identify the gene encoding neurofibromin 1 (Nf1) as an ICSBP target gene, by chromatin immunoprecipitation. Additionally, we find decreased Nf1 expression in bone marrow-derived myeloid cells from ICSBP-/- mice. Since Nf1 deficiency is also associated with cytokine hypersensitivity, our results suggested that NF1 is a functionally significant ICSBP target gene. Consistent with this, we find that the hypersensitivity of ICSBP-/- myeloid cells to granulocyte monocyte colony-stimulating factor (GM-CSF) is reversed by expression of the Nf1 GAP-related domain. We also find that treatment of ICSBP-deficient myeloid cells with monocyte colony-stimulating factor (M-CSF) results in sustained Ras activation, ERK phosphorylation, and proliferation associated with impaired Nf1 expression. These M-CSF effects are reversed by ICSBP expression in ICSBP-/- cells. Consistent with this, we find that ICSBP activates the NF1 promoter in myeloid cell line transfectants and identify an ICSBP-binding NF1 cis element. Therefore, the absence of ICSBP leads to Nf1 deficiency, impairing down-regulation of Ras activation by GM-CSF or M-CSF. These results suggest that one mechanism of increased myeloid proliferation, in ICSBP-deficient cells, is decreased NF1 gene transcription. This novel ICSBP function provides insight into regulation of myelopoiesis under normal conditions and in myeloproliferative disorders.

HoxA10 is a homeodomain (HD) transcription factor which is maximally expressed in committed myeloid progenitors and is overexpressed in acute myeloid leukemia (AML). Consistent with this, forced overexpression of HoxA10 in murine bone marrow leads to AML. Our studies identify a mechanism by which HoxA10-overexpression blocks differentiation, contributing to leukemogenesis. Previously, we found that HoxA10 represses transcription of the CYBB gene. This gene encodes the gp91phox component of the phagocyte respiratory burst oxidase and is actively transcribed in myeloid cells differentiated beyond the promyelocyte stage. CYBB transcription continues until cell death and is further increased in mature phagocytes by inflammatory mediators such as IFNg and LPS. In undifferentiated myeloid cells, HoxA10 represses CYBB transcription via a proximal promoter cis element with homology to the consensus sequence for HoxA10 DNA-binding as a heterodimer with Pbx1 (also a HD protein). However, we found that HoxA10 repression of CYBB transcription is Pbx1-independent and HDAC2-dependant. During cytokine induced differentiation, phosphorylation of two HoxA10 HD tyrosine residues decreases DNA-binding affinity and transcriptional repression. In the current studies, we investigate the impact of HoxA10 on transcription of the NCF2 gene. This gene, which encodes the p67phox phagocyte oxidase component, is transcribed concurrently with the CYBB gene during myelopoiesis and the inflammatory response. The NCF2 promoter also includes a sequence homologous to the HoxA10/Pbx1 DNA-binding consensus. In the current studies, we determine that HoxA10 functionally represses NCF2 transcription in undifferentiated myeloid cells in a Pbx1-independent, HDAC2-dependant manner. Additionally, we determine that NCF2-transcriptional repression by HoxA10 is abolished by phosphorylation of HD tyrosine residues in response to differentiating cytokines. In these studies, we also investigate the impact of IFNg-treatment of monocytes on HoxA10 phosphorylation and gp91phox and p67phox expression. We find that treatment of monocytes with this inflammatory mediator results in hyper tyrosine phosphorylation of HoxA10, which is necessary for IFNg-induced gp91phox and p67phox expression in these cells. These experiments suggest that HoxA10 contributes to differentiation block in AML by repressing transcription of genes that confer the mature myeloid phenotype. HoxA10 tyrosine phosphorylation abrogates transcriptional repression and may provide a molecular target for differentiation induction in AML. Additionally, HoxA10 hyper phosphorylation during the inflammatory response further increases oxidase gene expression. This represents the first demonstration that functions of HoxA10 contribute to gene regulation in mature phagocytes, contributing to the system of host defense.

Transcription of the CYBB gene, which encodes the respiratory burst oxidase protein, gp91phox, is restricted to phagocytic cells, differentiated beyond the promyelocyte stage. Regulation of CYBB transcription involves several repressor cis elements in the promoter. These repressor elements are homologous to the derived consensus sequence for DNA-binding of HoxA10 as a hetero-dimer with Pbx1a. The HoxA10/Pbx1 complex recruits histone deacetylase 2 and represses CYBB transcription in undifferentiated cells. During myeloid differentiation, HoxA10 is tyrosine phosphorylated, which decreases DNA-binding affinity for the CYBB repressor element. In our previous investigations, we found this decreased binding affinity requires phosphorylation of two tyrosine residues in the DNA-binding homeodomain. These residues are highly conserved with other HoxA proteins. However, we also found decreased DNA-binding requires interaction of these homeodomain tyrosines with a non-conserved domain, amino terminal in HoxA10. In previous investigations, we determined these CYBB repressor cis elements function as positive cis elements in differentiated myeloid cells, and interact with an unidentified protein complex. In these studies, we investigate the proteins involved in transcriptional activation of the CYBB gene, via these promoter sequences. We find this cis element is activated by HoxA9 and Pbx1a, in differentiating myeloid cells. Consistent with this, we find increased binding of HoxA9 to this CYBB cis element, during myeloid differentiation, in vitro and in vivo. Consistent with our results with HoxA10, we find HoxA9 is tyrosine phosphorylated during myeloid differentiation. However, in contrast to HoxA10, we find tyrosine phosphorylation of the conserved residues in the HoxA9 DNA-binding homeodomain increases binding to the CYBB cis element. Therefore, we conclude HoxA10 and HoxA9 have opposing functions, for myeloid specific gene transcription, during differentiation. We also find these functions are regulated by post translational modification of conserved tyrosine residues in the homeodomain regions of these proteins. Additionally, our results suggest differences in the effect of phosphorylation of these residues on DNA-binding is likely due to interaction with non-conserved domains in HoxA9 and HoxA10.