The Nature of the Antigen Determines Leukemia Development and Behavior in the Eμ-TCL1 Transgenic Mouse Model of CLL

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 181-181 ◽  
Author(s):  
Sara Bennardo ◽  
Stefano Iacovelli ◽  
Stefania Gobessi ◽  
Mirza Suljagic ◽  
Daniel Bilbao ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Clinical Course ◽  
Transgenic Mouse Model ◽  
Leukemic Cells ◽  
Apoptotic Cells ◽  
Gut Flora ◽  
Mutational Status ◽  
Membrane Bound ◽  
Leukemia Development ◽  
And Behavior

Abstract Abstract 181 Studies conducted over the past decade have revealed a strong association between the mutational status of the immunoglobulin heavy-chain variable region (IGHV) genes and clinical course in patients with chronic lymphocytic leukemia (CLL). In patients with aggressive CLL, the leukemic cells typically express B cell receptors (BCRs) encoded by unmutated IGHV genes, whereas these genes are most often mutated in leukemic cells from patients with indolent disease. The mutational status of the IGHV genes reflects features of the antigen, such as antigen structure, form, presentation and affinity, indicating that the difference in the clinical course between IGHV-unmutated and IGHV-mutated CLL could be due to recognition of different types of antigens. In line with this possibility, recent studies have shown that IGHV-unmutated CLL (U-CLL) cells frequently express polyreactive BCRs that bind with low affinity to both microbial antigens and autoantigens translocated or exposed on apoptotic cells, whereas such reactivity is infrequent in IGHV-mutated CLL (M-CLL). To further explore the possibility that the clinical course in CLL is determined by the availability of particular types of antigenic stimuli, we investigated the impact of different antigen/BCR interactions on leukemia development and behavior in the Eμ-TCL1 transgenic mouse model of CLL. We initially established three cohorts of Eμ-TCL1 transgenic mice that expressed transgenic BCRs with different antigen specificity. Two of these cohorts expressed low-affinity unmutated transgenic BCRs reactive with the antigens phosphatidylcholine (PtC) and Sm (IgPtC and IgSm, respectively), whereas the third cohort expressed a high-affinity mutated transgenic BCR (IgHEL) specific for the antigen hen egg lysozyme (HEL). Of note, Sm is a ribonucleoprotein complex that is translocated to the surface of apoptotic cells and has been shown to be recognized by certain human U-CLL BCRs, whereas PtC is a cell membrane component that is exposed on senescent red blood cells and gut bacteria. Because no data are currently available regarding the reactivity of the M-CLL BCRs, we subdivided the cohort of Eμ-TCL1/IgHEL double transgenic mice into four additional cohorts. These included a cohort without antigen (Eμ-TCL1/IgHEL), a cohort in which HEL was provided as a foreign antigen (Eμ-TCL1/IgHEL double transgenic mice repetitively immunized with particles coated with HEL and CpG oligonucleotides), a cohort in which HEL was provided as a soluble autoantigen (Eμ-TCL1/IgHEL/sHEL triple transgenic mice) and a cohort in which HEL was provided as a membrane-bound autoantigen exposed on apoptotic cells (Eμ-TCL1/IgHEL/mHEL-KK triple transgenic mice). Each cohort consisted of 12–14 animals, of which at least 8 have been followed for >1 year. Animals from all cohorts developed CD5-positive B cell leukemias, but only in Eμ-TCL1/IgSm and Eμ-TCL1/IgPtC mice the leukemic cells expressed a transgenic BCR. In Eμ-TCL1/IgHEL mice the leukemias were always derived from the small percentage of B cells that express an endogenous BCR, whereas B cells that express the transgenic IgHEL BCR were never transformed. Interestingly, leukemia development and progression was more rapid in Eμ-TCL1/IgPtC than Eμ-TCL1/IgSm transgenic mice (7/14 at 6 months of age and 2/10 at 8 months of age, respectively). Since PtC is expressed as both a foreign- (gut flora) and self- (senescent red blood cells) antigen, we investigated whether suppression of gut flora will affect the growth of adoptively transferred Eμ-TCL1/IgPtC leukemias. Pretreatment of syngeneic recipient mice with a three-week course of broad-spectrum antibiotics significantly delayed leukemia growth, suggesting that PtC is more potent in driving the expansion of the leukemic clone when expressed as a foreign than self antigen. To summarize, these data demonstrate that U-CLL can be induced by both microbial antigens and autoantigens exposed on apoptotic cells, including autoantigens that are recognized by human CLL cells, such as Sm. In contrast, M-CLL can not be induced by chronic or repetitive antigen stimulation, regardless whether the antigen is provided as a foreign antigen, as a soluble autoantigen, or as a membrane-bound autoantigen exposed on apoptotic cells. Collectively, these data suggest that the mechanisms that drive U-CLL and M-CLL are different and indicate that only U-CLL is an antigen-driven disease. Disclosures: No relevant conflicts of interest to declare.

Expression of ZAP-70 Does Not Accelerate Leukemia Development and Progression in the Eμ-TCL1 Transgenic Mouse Model of Chronic Lymphocytic Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 925-925
Author(s):  
Stefania Gobessi ◽  
Francesca Belfiore ◽  
Sara Bennardo ◽  
Brendan Doe ◽  
Luca Laurenti ◽  
...  
Keyword(s):  
T Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Mouse Model ◽  
Leukemic Cell ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Leukemia Development ◽  
Low Levels ◽  
And Behavior

Abstract Abstract 925 One of the most relevant prognostic factors in chronic lymphocytic leukemia (CLL) is expression of the protein tyrosine kinase ZAP-70. Typically, patients whose leukemic cells express ZAP-70 at 30–100% of the levels in normal T cells have aggressive disease, whereas patients whose leukemic cells do not express ZAP-70 or express only low levels of this protein have indolent disease. Previously, we and others demonstrated that ZAP-70 modulates B-cell receptor signaling and thus affects the capacity of the leukemic cells to respond to antigen stimulation. However, a direct link between an altered antigen response and CLL pathogenesis has still not been established and, more importantly, the question whether ZAP-70 directly contributes to the aggressiveness of the disease or is just a marker of aggressive CLL still remains to be answered. We have now addressed these issues by analyzing in vivo the impact of forced expression of ZAP-70 on the development and behavior of leukemias that arise in the Eμ-TCL1 transgenic (tg) mouse model of CLL. This model is characterized by the development of antigen-driven leukemias that resemble human CLL in many aspects but are always ZAP-70-negative. To force the expression of ZAP-70 in TCL1 leukemias, we generated two tg lines with targeted expression of ZAP-70 in the B cell compartment (ZAP70high and ZAP70low) and crossed them with Eμ-TCL1 tg mice. B cells in ZAP70high tg mice express similar levels of ZAP-70 as normal mouse T cells, whereas the levels of ZAP-70 in B cells of ZAP70lowtg mice are approximately 10 times lower. Both cohorts of Eμ-TCL1/ZAP70 double tg mice developed characteristic TCL1 leukemias. Eμ-TCL1/ZAP70low tg mice developed leukemias with onset and rate of progression similar to their ZAP-70-negative littermates, indicating that low levels of ZAP-70 do not alter the development and behavior of the disease. Surprisingly, Eμ-TCL1/ZAP70high tg mice developed leukemias with an approximately 2 month delay compared to their ZAP-70-negative Eμ-TCL1 tg littermates, which was contrary to the expectation that high ZAP-70 expression will accelerate leukemia development. The delay in leukemia development was especially evident at 6 months of age, when leukemic cells could be detected in the PB of 77% (10/13) of Eμ-TCL1 tg mice and only 24% (4/17) of Eμ-TCL1/ZAP70hightg mice (P=0.011). Since ZAP-70 expression can affect the migratory and adhesion capacity of human CLL cells in vitro, we first investigated if the delayed appearance of leukemic cells in the PB of Eμ-TCL1/ZAP70high tg mice could be due to increased retention of the leukemic cells in the lymphoid tissues. Assessment of tumor burden in the spleen, peritoneal cavity (PC), bone marrow and PB of 7 months old mice showed that the number of tumor cells in each compartment was significantly lower in Eμ-TCL1/ZAP70hightg mice than their Eμ-TCL1 littermates, suggesting that the delay in leukemia appearance is not caused by increased tissue retention but rather by reduced tumor growth. To investigate if ZAP-70 impairs tumor growth by affecting proliferation, we performed in vivo BrdU incorporation analysis of leukemic cells from spleen and PC of Eμ-TCL1 and Eμ-TCL1/ZAP70high tg mice. Spleen and PC samples were analyzed because they are the major sites of leukemia proliferation in Eμ-TCL1 tg mice. Interestingly, while the percentage of proliferating leukemic cells in the spleens of Eμ-TCL1 and Eμ-TCL1/ZAP70high tg mice was similar (mean % of BrdU+ cells ±SD: 6.81 ±1.67 and 6.15 ±2.92, respectively; P=n.s.), the percentage of proliferating leukemic cells in the PC of Eμ-TCL1/ZAP70high tg mice was significantly lower (mean % of BrdU+cells ±SD: 1.74 ±1.05 and 0.56 ±0.39, respectively; P=0.024). In summary, this study shows that ZAP-70 expression, per se, is unable to accelerate leukemia development and progression in an established in vivo model of CLL and suggests that ZAP-70 is not directly responsible for the greater disease severity in the poor prognosis subset of CLL. In addition, this study reveals that ZAP-70 in certain tissue environments can function as a negative regulator of leukemic cell proliferation, contrary to the widespread perception of ZAP-70 as a positive regulator of leukemic cell responses. Disclosures: No relevant conflicts of interest to declare.

Angiogenic Activity in IgVH Mutated and Unmutated Chronic Lymphocytic Leukemia (CLL): Indications for the Therapeutic Use of VEGF-Signaling Inhibitors.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2819-2819
Author(s):  
Roberta Maggio ◽  
Nadia Peragine ◽  
Monica Messina ◽  
Sabina Chiaretti ◽  
Stefania M. De Propris ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Prognostic Factors ◽  
Clinical Course ◽  
Leukemic Cells ◽  
Human Endothelial Cells ◽  
Tubule Formation ◽  
Vegf Signaling ◽  
Anti Vegf ◽  
Mutational Status ◽  
Signaling Inhibitors

Abstract Background: CLL is characterized by an heterogeneous clinical course, with some patients living many years without therapy and other patients presenting an aggressive disease. Different biologic properties of the leukemic cells have important prognostic implications. In particular, the IgVH gene mutational status, chromosomal abnormalities, expression of CD38 and ZAP-70 have been correlated with the clinical course of the disease. There is also growing evidence that angiogenesis may be linked to the pathogenesis and outcome of CLL. In particular, vascular endothelial growth factor A (VEGF-A) has been detected in the serum and bone marrow biopsy cells analyzed by immunostaining: both events have been correlated with a poor prognostic likelihood. Aims: The goal of this study was to obtain a more complete characterization of the angiogenic potential of CLL cells, to correlate the angiogenic capacity with other prognostic parameters and to investigate the possibility of overcoming this property by specific VEGF-signaling inhibitors. Methods: Eighteen patients with a diagnosis of CLL, based on morphologic and immunophenotypic criteria, have been evaluated for the expression of CD38 and ZAP-70, and for the IgVH gene mutational status. An Angiokit test (TCS Cell Works) was utilized to evaluate the capacity of purified CD19+ CLL cells to stimulate the growth and tubule formation of human endothelial cells and the relative roles of an anti-VEGF specific antibody and of PTK787/ZK 222584 (PTK/ZK, Schering, Novartis), a novel, oral angiogenesis and lymphangiogenesis inhibitor that blocks tyrosine kinase signaling from all known VEGFRs. The quantification of endothelial tubule formation was carried out using a specific software. After stimulation with a biotinylated goat anti-human IgM F(ab)2, leukemia cells were evaluated for gene expression profiling using the Affymetrix HGU133 Plus 2.0 gene chip. Results: In 9 patients, the leukemic cells were CD38+, ZAP-70+ and showed an unmutated IgVH status; in the remaining 9, the leukemic cells were CD38−, ZAP-70− and with a mutated IgVH status. In CLL patients with poor prognostic features - CD38+, ZAP-70+ and unmutated IgVH - purified leukemic cells showed a significantly greater capacity to stimulate the growth and tubule formation (3407 ± 968 tubules) of human endothelial cells compared to leukemic cells obtained from CLL patients with good prognostic factors, i.e. CD38−, ZAP-70− and mutated IgVH, (1550 ± 624 tubules). This property was amplified following sIgM cross-linking, that resulted in the upregulation of angiogenetic genes, including: EGR-1, SDF2L1, TNFAIP3, PTGER4, FIBP, NR4A3. A reduction of VEGF-A-induced tubule number was observed when leukemic cells were cultured with the anti-VEGF antibody (43–82% of inhibition) and, to a further extent, with the PTK/ZK inhibitor (90–96% of inhibition) compared to purified CLL cells alone. Conclusions: In CLL patients with poor prognostic factors, leukemic cells display an angiogenic capability significantly higher than that of cells from patients with favorable prognostic factors. The current findings provide the rationale for investigating the potential clinical role of anti-angiogenic agents, such as PTK/ZK, in the management of CLL patients.

High Expression of Haematopoietic Cell Specyfic Lyn Substrate-1 (HS1) Predicts Survival of B-Cell Chronic Lymphocytic Leukemia Patients

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2853-2853
Author(s):  
Aleksandra Butrym ◽  
Miroslaw Majewski ◽  
Justyna Dzietczenia ◽  
Tomasz Wrobel ◽  
Kazimierz Kuliczkowski ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Patient Survival ◽  
Clinical Course ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Mutational Status ◽  
Cell Chronic Lymphocytic Leukemia

Abstract Abstract 2853 B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in adults in western countries. It is characterized by B lymphocyte accumulation in peripheral blood, bone marrow, lymph nodes and other lymphatic organs. Leukemic cells derive most commonly from B lymphocytes, rarely from T or NK cells. B-CLL is known from its heterogeneous clinical course from indolent to very aggressive. In spite of many known prognostic factors (such as immunoglobulin heavy chain gene mutational status – IgVH, expression of ZAP70 and CD38), is still difficult to classify a single patient to particular risk group and to predict CLL clinical course. That is why new prognostic factors are still needed. HS1 (hematopoietic cell specific Lyn substrate-1) is an intracellular protein, which expression occurs mainly in hematopoietic cells. HS1 plays an important role in regulating T cell immune synapse and affects many functions of NK cells, including the lysis of target cells, adhesion, chemotaxis and clustering of actin in the lytic synapse. The role of HS1 in B cells is poorly understood. This protein was identified in B cells as the primary receptor substrate for phosphorylation by BCR after antigenic stimulation. Other studies have confirmed the role of HS1 in the process of clonal expansion and deletion induced by antigen-receptor interaction in B cells and T. HS1 is rapidly phosphorylated in B cells in the vicinity of tyrosine residues and is a substrate for tyrosine kinases: the Src family and Syk, including Lyn, FGR, Fyn and Lck. It has been shown that HS1 interacts with the cell cytoskeleton in both: normal and leukemic B cells. HS1 protein is an important regulator of motility, migration and adhesion of leukemic cells and is involved in cytoskeleton rearrangement. HS1 can have impact on homing and migration of CLL cells. It can indirectly promote disease progression and influence patient survival. The aim of this study was to evaluate HS1 expression in CLL patients in connection with other known prognostic factors and patient survival. Material and methods: 92 untreated CLL patients (45 women and 47 men), aged between 42 and 88 years (median age 67 years), were included into the study. Diagnosis was made basing on typical clinical, hematological and immunophenotypical picture. The control group was consist of 28 healthy matched people (11 men and 17 women), aged between 36 and 79 years (median age 59 years). HS1 protein expression was determined by western blot. Comparative semi-quantitative indication of the degree of saturation of the bands analyzed by densitometry using the gel documentation system Gel-Doc (Bio-Rad) and a computer program to analyze the 1-D Quantity One (Bio-Rad). Assuming conventional units [AU - arbitrary units], depending on the saturation band, patients were divided into four groups with the expression of HS1 protein expressed in value from 0 to 3. Lack of expression was expressed as 0 [AU], and expression of the strongest, with the highest saturation band measured as 3 [AU]. Mutational status of IgVH, as well as CD38 and ZAP70 expression were also analyzed. Results: HS1 expression was significantly higher in CLL patients comparing to controls. Positive correlation was shown between HS1 and: age (p=0.0454), Rai stage (p=0.0412), leukocytosis (p=0.0129) and β2-microglobulin (p=0.0342). There was negative correlation between HS1 and hemoglobin level (p=0.0464) and platelet count (p=0.0310). Patients with lymphocyte doubling time shorter or equal to 6 months had higher expression of HS1. Expression of HS1 significantly influenced survival of CLL patients. Patients with higher HS1 expression had shorter survival than those with lower HS1 expression (p=0.0329). Conclusions: 1. Higher HS1 expression is observed in more advanced CLL stages. 2. Expression of HS1 in CLL cells is matched with shorter patient survival The relationship between expression of HS1 and survival of patients with B-CLL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Preclinical Detection of Alpha-Synuclein Seeding Activity in the Colon of a Transgenic Mouse Model of Synucleinopathy by RT-QuIC

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 759
Author(s):  
Jung-Youn Han ◽  
Chaewon Shin ◽  
Young Pyo Choi
Keyword(s):  
Mouse Model ◽  
Transgenic Mice ◽  
Lewy Body ◽  
Dementia With Lewy Body ◽  
Transgenic Mouse Model ◽  
Alpha Synuclein ◽  
Gi Tract ◽  
Colon Tissue ◽  
Presymptomatic Stage ◽  
The Brain

In synucleinopathies such as Parkinson’s disease (PD) and dementia with Lewy body (DLB), pathological alpha-synuclein (α-syn) aggregates are found in the gastrointestinal (GI) tract as well as in the brain. In this study, using real-time quaking-induced conversion (RT-QuIC), we investigated the presence of α-syn seeding activity in the brain and colon tissue of G2-3 transgenic mice expressing human A53T α-syn. Here we show that pathological α-syn aggregates with seeding activity were present in the colon of G2-3 mice as early as 3 months old, which is in the presymptomatic stage prior to the observation of any neurological abnormalities. In contrast, α-syn seeding activity was not detectable in 3 month-old mouse brains and only identified at 6 months of age in one of three mice. In the symptomatic stage of 12 months of age, RT-QuIC seeding activity was consistently detectable in both the brain and colon of G2-3 mice. Our results indicate that the RT-QuIC assay can presymptomatically detect pathological α-syn aggregates in the colon of G2-3 mice several months prior to their detection in brain tissue.

Partial Leptin Receptor Gene Deletion in Transgenic Mice Prevents Expression of the Membrane-Bound Isoforms Except for Ob-Rc

2000 ◽  
Vol 269 (2) ◽  
pp. 496-501 ◽  
Author(s):  
Ursula Reichart ◽  
Roland Kappler ◽  
Harry Scherthan ◽  
Eckhard Wolf ◽  
Mathias Müller ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Gene Deletion ◽  
Leptin Receptor ◽  
Receptor Gene ◽  
Membrane Bound

scholarly journals Asynchronous expression of myeloid antigens in leukemic cells in a PML/RARalpha transgenic mouse model

2006 ◽  
Vol 39 (5) ◽  
pp. 615-620 ◽  
Author(s):  
B.A.A. Santana ◽  
M.C. Pintão ◽  
R.S. Abreu e Lima ◽  
P.S. Scheucher ◽  
G.A.S. Santos ◽  
...  
Keyword(s):  
Mouse Model ◽  
Transgenic Mouse ◽  
Transgenic Mouse Model ◽  
Leukemic Cells ◽  
Myeloid Antigens

scholarly journals Functional and structural connectome properties in the 5XFAD transgenic mouse model of Alzheimer’s disease

2018 ◽  
Vol 2 (2) ◽  
pp. 241-258 ◽  
Author(s):  
Shelli R. Kesler ◽  
Paul Acton ◽  
Vikram Rao ◽  
William J. Ray
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Transgenic Mice ◽  
Transgenic Mouse ◽  
Amyloid Beta ◽  
Molecular Mechanisms ◽  
Diffusion Tensor ◽  
Transgenic Mouse Model ◽  
Structural Connectome

Neurodegeneration in Alzheimer’s disease (AD) is associated with amyloid-beta peptide accumulation into insoluble amyloid plaques. The five-familial AD (5XFAD) transgenic mouse model exhibits accelerated amyloid-beta deposition, neuronal dysfunction, and cognitive impairment. We aimed to determine whether connectome properties of these mice parallel those observed in patients with AD. We obtained diffusion tensor imaging and resting-state functional magnetic resonance imaging data for four transgenic and four nontransgenic male mice. We constructed both structural and functional connectomes and measured their topological properties by applying graph theoretical analysis. We compared connectome properties between groups using both binarized and weighted networks. Transgenic mice showed higher characteristic path length in weighted structural connectomes and functional connectomes at minimum density. Normalized clustering and modularity were lower in transgenic mice across the upper densities of the structural connectome. Transgenic mice also showed lower small-worldness index in higher structural connectome densities and in weighted structural networks. Hyper-correlation of structural and functional connectivity was observed in transgenic mice compared with nontransgenic controls. These preliminary findings suggest that 5XFAD mouse connectomes may provide useful models for investigating the molecular mechanisms of AD pathogenesis and testing the effectiveness of potential treatments.

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