Hypothesis: Tim-3/Galectin-9, A New Pathway for Leukemia Stem Cells Survival by Promoting Expansion of Myeloid-Derived Suppressor Cells and Differentiating into Tumor-Associated Macrophages

Despite the improvements in chemotherapy, about 60 % of acute myeloid leukemia (AML) remission patients still relapse. Leukemic stem cells (LSCs) are the main causes for the relapse and refractory. T cell immunoglobulin mucin-3 (TIM-3), a specific surface molecule expressed on LSCs in most types of AML, is a candidate for AML LSC-targeted therapies. It is important to know how this molecule functions in the maintenance of LSCs and suppression of anti-tumor immunity. Recent data have shown that Tim-3 which expresses on T cells can suppress immune responses indirectly by inducing expansion of myeloid-derived suppressor cells (MDSCs). MDSCs at the leukemia site can also differentiate into tumor-associated macrophages (TAMs). TAMs can promote proliferation and survival of LSCs by the diversion of adaptive immunity and the facilitation of extracellular matrix remodeling, angiogenesis, and lymphangiogenesis. Our previous study in AML patient bone marrow samples showed CD68⁺ macrophages around AML clone. Based on the known evidence and our experimental findings, we hypothesize that Tim-3, which specifically expresses on LSCs, is beneficial for LSCs survival and AML progression by promoting expansion of MDSCs and differentiating into TAMs at the leukemia site.     

Primary alveolar macrophages exposed to diesel particulate matter increase RAGE expression and activate RAGE signaling

Receptors for advanced glycation end-products (RAGE) are members of the immunoglobulin superfamily of cell-surface receptors implicated in mechanisms of pulmonary inflammation. In the current study, we test the hypothesis that RAGE mediates inflammation in primary alveolar macrophages (AMs) exposed to diesel particulate matter (DPM). Quantitative RT-PCR and immunoblotting revealed that RAGE was up-regulated in Raw264.7 cells, an immortalized murine macrophage cell line and primary AMs exposed to DPM for 2 h. Because DPM increased RAGE expression, we exposed Raw264.7 cells and primary AMs isolated from RAGE null and wild-type (WT) mice to DPM prior to the assessment of inflammatory signaling intermediates. DPM led to the activation of Rat sarcoma GTPase (Ras), p38 MAPK and NF-κB in WT AMs and, when compared to WT AMs, these intermediates were diminished in DPM-exposed AMs isolated from RAGE null mice. Furthermore, cytokines implicated in inflammation, including IL-4, IL-12, IL-13 and TNFα, were all significantly decreased in DPM-exposed RAGE null AMs compared to similarly exposed WT AMs. These results demonstrate that diesel-induced inflammatory responses by primary AMs are mediated, at least in part, via RAGE signaling mechanisms. Further work may show that RAGE signaling in both alveolar epithelial cells and resident macrophages is a potential target in the treatment of inflammatory lung diseases exacerbated by environmental pollution.     

Quercetin Potentiates the Antitumor Activity of Rituximab in Diffuse Large B-Cell Lymphoma by Inhibiting STAT3 Pathway

STAT3 pathway plays an important role in the growth of diffuse large B-cell lymphoma (DLBCL) cells. Here we investigated the antitumor activity of Quercetin, a flavonoid compound, in combination with rituximab in DLBCL cell lines in vitro. We found that Quercetin synergistically enhanced rituximab-induced growth inhibition and apoptosis in DLBCL cell lines. Moreover, we found Quercetin exerted inhibitory activity against STAT3 pathway and downregulated the expression of survival genes. These results suggest that combining the Quercetin with rituximab may present an attractive and potentially effective way for the treatment of DLBCL.     

Polymorphism of DNA Repair Gene xrcc1 and Lung Cancer Risk

The current large-scale meta-analysis was performed to reach a reliable conclusion on the association between X-ray repair cross-complementing 1 (xrcc1) rs1799782 and the development of lung cancer. Studies that investigated the association between rs1799782 and lung cancer risk were identified by searching PubMed. We calculated odds ratio (OR) with corresponding 95 % confidence interval (CI) for Trp/Trp vs Arg/Arg, Trp/Trp + Arg/Trp vs Arg/Arg, and Trp/Trp vs Arg/Trp + Arg/Arg contrast models. Combining all 25 studies, we yielded three summary ORs: 1.07 (95 % CI 0.92–1.23) for Trp/Trp vs Arg/Arg, 0.93 (95 % CI 0.87–1.00) for Trp/Trp + Arg/Trp vs Arg/Arg, and 1.08 (95 % CI 0.94–1.25) for Trp/Trp vs Arg/Trp + Arg/Arg, suggesting rs1799782 was not associated with overall risk of lung cancer. Strikingly, a significantly deceased risk was found among Caucasian populations (Trp/Trp + Arg/Trp vs Arg/Arg, OR = 0.86, 95 % CI 0.76–0.97). This study confirms that xrcc1 rs1799782 may lower the risk of lung cancer among Caucasians.     

Quantitative and Multiplexed Study of Endothelial Cell Inflammation

Endothelial inflammation plays major roles in all phases of the atherosclerotic process, the leading cause of death by cardiovascular disease. Both innate immunity and endothelial adhesion molecules contribute to endothelial inflammation. In this work, we applied multiple antibodies (Abs) to measure changes in expression levels of six proteins in response to inflammatory stimulation. These six proteins include toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4) representing innate immunity and four endothelial adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), E-selectin, and P-selectin. We observed two different types of dynamic behaviors among these proteins upon inflammatory stimulation. Increased expression of toll-like receptor 2 (TLR2), P-selectin, E-selectin, and TLR4 peaked relatively early (after 4 h of stimulation) while VCAM-1, and ICAM-1 showed a more gradual and consistent increase in expression with stimulatory time. The magnitude of this increase was significantly greater for VCAM-1 and ICAM-1. The multiplexed detection developed in this study using fluorophore-conjugated primary Abs provides an approach for live cell and in vivo imaging of endothelium inflammation for quantitative characterization of multiple proteins within a network.     

Identification of nucleolus-localized PTEN and its function in regulating ribosome biogenesis

The tumor suppressor PTEN is a lipid phosphatase that is found mutated in different types of human cancers. PTEN suppresses cell proliferation by inhibiting the PI3K-Akt signaling pathway at the cell membrane. However, PTEN is also demonstrated to localize in the cell nucleus where it exhibits tumor suppressive activity via a different, unknown mechanism. In this study we report that PTEN also localizes to the nucleolus and that nucleolar PTEN plays an important role in regulating nucleolar homeostasis and maintaining nucleolar morphology. Overexpression of nuclear PTEN in PTEN null cells inhibits Akt phosphorylation and reduces cell size. Knockdown of PTEN in PTEN positive cells leads to nucleolar morphologic changes and an increase in the proportion of cells with a greater number of nucleoli. In addition, knockdown of PTEN in PTEN positive cells increased ribosome biogenesis. These findings expand current understanding of function and relevance of nuclear localized PTEN and provide a foundation for the development of novel therapies targeting PTEN.     

On the existence of two GABA pools associated with newly synthesized GABA and with newly taken up GABA in nerve terminals

[¹⁴C]Glutamic acid and [³H]GABA were injected into the lateral ventricle of mouse and then [¹⁴C]GABA and [³H]GABA in synaptosomes isolated from the animals were analysed. The [¹⁴C]GABA was interpreted to be newly synthesized GABA from [¹⁴C]glutamic acid while the [³H]GABA to be newly taken up GABA. We have obtained the following results: (1) when the animals were pretreated with aminooxyacetic acid and thus the GABA content in synaptosomes increased to about 2 times of the control level, only the [³H]GABA was enhanced to 3 times of the control level without any change of [¹⁴C]GABA, (2) the release of [¹⁴C]GABA from synaptosomes by high K⁺ depolarization was 1.5 times greater than that of [³H]GABA, (3) the releases of both [¹⁴C]GABA and [³H]GABA were increased in the presence of cold GABA,l-2,4-diaminobutyric acid or γ-amino-β-hydroxybutyric acid, but only slightly increased in the presence of β-alanine. These results would suggest that newly synthesized GABA and newly taken up GABA localized individually in different pools, which might localize either in different nerve terminals or separately in the same nerve terminal.     

Compositional analysis and structural elucidation of glycosaminoglycans in chicken eggs

Glycosaminoglycans (GAGs) have numerous applications in the fields of pharmaceuticals, cosmetics, nutraceuticals, and foods. GAGs are also critically important in the developmental biology of all multicellular animals. GAGs were isolated from chicken egg components including yolk, thick egg white, thin egg white, membrane, calcified shell matrix supernatant, and shell matrix deposit. Disaccharide compositional analysis was performed using ultra high-performance liquid chromatography-mass spectrometry. The results of these analyses showed that all four families of GAGs were detected in all egg components. Keratan sulfate was found in egg whites (thick and thin) and shell matrix (calcified shell matrix supernatant and deposit) with high level. Chondroitin sulfates were much more plentiful in both shell matrix components and membrane. Hyaluronan was plentiful in both shell matrix components and membrane, but was only present in a trace of quantities in the yolk. Heparan sulfate was plentiful in the shell matrix deposit but was present in a trace of quantities in the egg content components (yolk, thick and thin egg whites). Most of the chondroitin and heparan sulfate disaccharides were present in the GAGs found in chicken eggs with the exception of chondroitin and heparan sulfate 2,6-disulfated disaccharides. Both CS and HS in the shell matrix deposit contained the most diverse chondroitin and heparan sulfate disaccharide compositions. Eggs might provide a potential new source of GAGs.     

Analysis of the temperature-dependent temporal pattern of heat-shock-protein synthesis in fish cells

Continuous exposure of Chinook salmon embryo cells to an elevated incubation temperature of 24°C induces the transient expression of a set of heat-shock or stress proteins whereas maintenance of the cells at a higher incubation temperature of 28°C produces a continuous synthesis of these stress proteins. In vitro translation studies suggest that the temperature-dependent temporal pattern of stress-protein synthesis is correlated with the levels of stress-protein mRNA. This was verified using a recombinant-DNA probe complementary to the 70K heat-shock-protein mRNA. A transient increase in the level of the fish heat-shock 70K mRNA was observed in RNA samples isolated from cells continuously exposed at 24°C However, a constant increase in the level of this specific mRNA was found in RNA preparations obtained from cells maintained at 28°C Therefore, the temperature-dependent pattern of fish heat-shockprotein synthesis appears to be directly related to the level of heat-shock-protein mRNA.     

The effect of glucagon-like peptide-1 in the management of diabetes mellitus: cellular and molecular mechanisms

Incretins, such as glucagon-like peptide-1 (GLP)-1, have been shown to elevate plasma insulin concentration. The purpose of this study is to investigate the cellular and molecular basis of the beneficial effects of GLP-1. Normal and diabetic male Wistar rats were treated with GLP-1 (50 ng/kg body weight) for 10 weeks. At the end of the experiment, pancreatic tissues were taken for immunohistochemistry, immunoelectron microscopy and real-time polymerase chain reaction studies. Samples of blood were retrieved from the animals for the measurement of enzymes and insulin. The results show that treatment of diabetic rats with GLP-1 caused significant (P?GLP-1 (10^?12–10^?6 M) induced significant (P?GLP-1-treated rats compared to controls. GLP-1 treatment induced significant (P?GLP-1-receptor genes in diabetic animals compared to controls. GLP-1 is present in pancreatic beta cells and significantly (P?GLP-1 is co-localized with insulin and seems to exert its beneficial effects by increasing cellular concentrations of endogenous antioxidant genes and other genes involved in the maintenance of pancreatic beta cell structure and function.     

Serum IgG levels in the Storrs strain of hereditary muscular dystrophic chickens

IgG levels in sera of Storrs hereditary muscular dystrophic chickens were investigated. IgG levels in age-matched Storrs muscular dystrophic chickens varied, depending on the geographical location where the chickens were reared. IgG levels from muscular dystrophic chickens at varying ages of development were approximately 30% less than age-matched control values. Genetic analyses of F₁ hybrid, F₂ progeny, and testcross progeny showed the reduced IgG levels in the Storrs strain of muscular dystrophic chickens not to be correlated with the autosomal recessive muscular dystrophic trait, the degree of muscle destruction, nor with an autosomal recessive T cell defect. The studies reported here suggest (1) that the reduced IgG levels in the Storrs strain of muscular dystrophic chickens are due to strain differences and (2) that the mode of inheritance of serum IgG levels in the Storrs strain of muscular dystrophic chickens is polygenic.     

Imaging Functional and Structural Brain Connectomics in Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopment disorders in childhood. Clinically, the core symptoms of this disorder include inattention, hyperactivity, and impulsivity. Previous studies have documented that these behavior deficits in ADHD children are associated with not only regional brain abnormalities but also changes in functional and structural connectivity among regions. In the past several years, our understanding of how ADHD affects the brain’s connectivity has been greatly advanced by mapping topological alterations of large-scale brain networks (i.e., connectomes) using noninvasive neurophysiological and neuroimaging techniques (e.g., electroencephalograph, functional MRI, and diffusion MRI) in combination with graph theoretical approaches. In this review, we summarize the recent progresses of functional and structural brain connectomics in ADHD, focusing on graphic analysis of large-scale brain systems. Convergent evidence suggests that children with ADHD had abnormal small-world properties in both functional and structural brain networks characterized by higher local clustering and lower global integrity, suggesting a disorder-related shift of network topology toward regular configurations. Moreover, ADHD children showed the redistribution of regional nodes and connectivity involving the default-mode, attention, and sensorimotor systems. Importantly, these ADHD-associated alterations significantly correlated with behavior disturbances (e.g., inattention and hyperactivity/impulsivity symptoms) and exhibited differential patterns between clinical subtypes. Together, these connectome-based studies highlight brain network dysfunction in ADHD, thus opening up a new window into our understanding of the pathophysiological mechanisms of this disorder. These works might also have important implications on the development of imaging-based biomarkers for clinical diagnosis and treatment evaluation in ADHD.     

Roles of glycosaminoglycans and glycanmimetics in tumor progression and metastasis

Various tumor cells exhibit structural alterations in the sulfated modifications to glycosaminoglycans (GAGs). The altered expression of chondroitin sulfate (CS) and heparan sulfate (HS) on the surfaces of tumor cells is known to play a key role in malignant transformation and tumor metastasis. The receptor molecule for the CS chains containing E-disaccharide units (CS-E) expressed on Lewis lung carcinoma (LLC) cells was recently revealed to be Receptor for Advanced Glycation End-products (RAGE). RAGE is also involved in the development of various pathological conditions including aging, infection, pulmonary fibrosis, diabetes, and Alzheimer’s disease, by binding to a wide range of ligands. RAGE binds strongly not only to CS-E, but also to HS-expressing LLC cells. Recombinant RAGE bound CS-E and HS with high affinity. Furthermore, in a mouse model, the colonization of the lungs by LLC cells was inhibited by intravenously injected CS-E, an anti-CS-E antibody, or an anti-RAGE antibody. These findings demonstrated that RAGE is at least one of the critical receptors for CS and HS chains expressed on the tumor cell surface and is involved in experimental lung metastasis, and also that CS/HS and RAGE are potential molecular targets for the treatment of pulmonary metastasis. We, hence, reviewed these findings and also several chemically synthesized small GAGmimetics that exhibit potent anti-metastatic and/or anti-tumor activities.