Sex-dependent expression levels of VAV1 and P2X7 in PBMC of multiple sclerosis patients

Multiple sclerosis (MS) is an inflammatory autoimmune disorder of the central nervous system and the leading cause of progressive neurological disability in young adults. It decreases the patient's lifespan by about 10 years and affects women more than men. No medication entirely restricts or reverses neurological degradation. However, early diagnosis and treatment increase the possibility of a better outcome. To identify new MS biomarkers, we tested the expression of six potential markers (P2X4, P2X7, CXCR4, RGS1, RGS16 and VAV1) using qPCR in peripheral blood mononuclear cells (PBMC) of MS patients treated with interferon β (IFNβ), with glatiramer acetate (GA) or untreated. We showed that P2X7 and VAV1 are significantly induced in MS patients. In contrast, the expression of P2X4, CXCR4, RGS1 and RGS16 was not significantly modified by MS in PBMC. P2X7 and VAV1 are essentially induced in female patients, suggesting these markers are connected to sex-specific mechanisms. Strikingly, VAV1 expression is higher in healthy women than healthy men and IFNβ treatment of MS reduced VAV1 expression in female MS patients while it up-regulated VAV1 in male MS patients. Our data point to the differential, sex-dependent value of MS markers and treatment effects. Although rgs16 expression in PBMC was not a valid MS marker in patients, the strong upregulation of P2X4 and P2X7 induced in the spinal cord of WT mice by EAE was abrogated in rgs16KO mice suggesting that rgs16 is required for P2X4 and P2X7 induction by neurological diseases.

Unraveling the Oncogenic Potential of VAV1 in Human Cancer: Lessons from Mouse Models

VAV1 is a hematopoietic signal transducer that possesses a GDP/GTP nucleotide exchange factor (GEF) that is tightly regulated by tyrosine phosphorylation, along with adapter protein domains, such as SH2 and SH3. Research on VAV1 has advanced over the years since its discovery as an in vitro activated oncogene in an NIH3T3 screen for oncogenes. Although the oncogenic form of VAV1 first identified in the screen has not been detected in human clinical tumors, its wild-type and mutant forms have been implicated in mammalian malignancies of various tissue origins, as well as those of the hematopoietic system. This review article addresses the activity of human VAV1 as an overexpressed or mutated gene and also describes the differences in the distribution of VAV1 mutations in the hematopoietic system and in other tissues. The knowledge accumulated thus far from GEMMs expressing VAV1 is described, with the conclusion that GEMMs of both wild-type VAV1 and mutant VAV1 do not form tumors, yet these will be generated when additional molecular insults, such as loss of p53 or KRAS mutation, occur.

Oncogenic Vav1-Myo1f induces therapeutically targetable macrophage-rich tumor microenvironment in peripheral T cell lymphoma

Peripheral T cell lymphoma not otherwise specified (PTCL-NOS) comprises heterogeneous lymphoid malignancies characterized by pleomorphic lymphocytes and variable inflammatory cell-rich tumor microenvironment. Genetic drivers in PTCL-NOS include genomic alterations affecting the VAV1 oncogene; however, their specific role and mechanisms in PTCL-NOS remain incompletely understood. Here we show that expression of Vav1-Myo1f, a recurrent PTCL-associated VAV1 fusion, induces oncogenic transformation of CD4⁺ T cells. Notably, mouse Vav1-Myo1f lymphomas show T helper type 2 features analogous to high-risk GATA3⁺ human PTCL. Single-cell transcriptome analysis reveals that Vav1-Myo1f alters T cell differentiation and leads to accumulation of tumor-associated macrophages (TAMs) in the tumor microenvironment, a feature linked with aggressiveness in human PTCL. Importantly, therapeutic targeting of TAMs induces strong anti-lymphoma effects, highlighting the lymphoma cells' dependency on the microenvironment. These results demonstrate an oncogenic role for Vav1-Myo1f in the pathogenesis of PTCL, involving deregulation in T cell polarization, and identify the lymphoma-associated macrophage-tumor microenvironment as a therapeutic target in PTCL.

High Expression of VAV Gene Family Predicts Poor Prognosis of Acute Myeloid Leukemia

Objectives: VAV family genes (VAV1, VAV2, and VAV3) are associated with prognosis in various cancers; however, they have not been evaluated in acute myeloid leukemia (AML). In this study, the prognostic value of VAV expression in AML was evaluated by a single-center study in combination with bioinformatics analyses. Methods: The expression and prognostic value of VAVs in patients with AML were investigated using various databases, including GEPIA, CCLE, EMBL-EBI, UALCAN, cBioPortal, STRING, and DAVID. Blood samples from 35 patients with AML (non-M3 subtype) and 13 benigh individuals were collected at our center. VAV expression levels were detected by real-time quantitative PCR (RT-qPCR) and western blotting. Clinical data were derived from medical records. Results: Based on data from multiple databases, the expression levels of VAV1, VAV2, and VAV3 were significantly higher in AML than in control tissues (P < 0.05). RT-qPCR and western blotting results showed that VAV expression in mRNA and protein levels were higher in patients with AML that in the control group (P < 0.05). Complete remission rates were lower and risks were higher in patients with AML with high VAV1 expression than with low VAV1 expression (P < 0.05). High levels of VAV2, VAV3, and VAV1 were related to a poor overall survival, and this relationship was significant for VAV1 (P < 0.05). High expression levels of genes correlated with VAV1, such as SIPA1, SH2D3C, and HMHA1 were also related to a poor prognosis in AML. Functional and pathways enrichment analyses indicated that the contribution of the VAV family to AML may be mediated by the NF-κB, cAMP, and other pathways. Conclusion: VAVs were highly expressed in AML. In particular, VAV1 has prognostic value and is a promising therapeutic target for AML.

VAV1-overexpressing YT cells display improved cytotoxicity against malignant cells

Immunotherapy based on adoptive transfer of genetically engineered T- and NK-cells is an area of active ongoing research and has proven highly efficacious for patients with certain B-cell malignancies. Use of NK cells and NK cell lines as carriers of chimeric antigen receptors (CARs) appears particularly promising, as this opens an opportunity for moving the therapy from autologous to the allogeneic (universal) format. This "off-the-shelf" approach is thought to significantly reduce the price of the treatment and make it available to many more patients in need. Yet, the efficacy of CAR-NK cells in vivo presently remains low, and boosting the activity of CAR NK cells via stronger tumor homing, resistance to tumor microenvironment, as well as greater cytotoxicity may translate into improved patient outcomes. Here, we established a derivative of a human NK cell line YT overexpressing a positive regulator of cytotoxicity, VAV1. Activity of YT-VAV1 cells obtained was assayed in vitro against several cancer cell lines and primary patient-derived cancer cells. YT-VAV1 cells outperform parental YT cells in terms of cytotoxicity.

VAV1 Gene Polymorphisms in Patients with Rheumatoid Arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is an important public health problem because this disease often causes disability. RA is a chronic, destructive autoimmune disease that leads to joint destruction and the development of extraarticular manifestations. VAV1 is an intracellular signal transduction protein that plays a significant role in signal transduction in T cells and affects T cell development, proliferation and activation. The VAV1 gene contains 27 exons and is located on chromosome 19. In this study, we examined the association between VAV1 rs2546133 and rs2617822 polymorphisms and RA.

METHODS

We examined 422 patients with RA and 338 healthy subjects as the control group.

RESULTS

Among RA patients, there was a statistically significant increase in the frequency of VAV1 rs2546133 polymorphism in T allele carriers (TT + CT versus CC, odds ratio: 1.69, 95% confidence interval 1.05-2.73, p = 0.035). There was no statistically significant difference in the distribution of the rs2617822 genotypes and alleles between RA patients and the control group. Additionally, patients who carried the VAV1 rs2546133 T and rs2617822 G allele presented an increased frequency of extraarticular manifestations: vasculitis, amyloidosis and Sjogren syndrome.

CONCLUSIONS

The results suggest an association between VAV1 gene rs2617822 polymorphism and RA.

MicroRNA-326 decreases tau phosphorylation and neuron apoptosis through inhibition of the JNK signaling pathway by targeting VAV1 in Alzheimer's disease

Alzheimer's disease (AD) is a progressive and age-related neurological dysfunction. Abundant data have profiled microRNA (miR) patterns in healthy, aging brain, and in the moderate and late-stages of AD. Herein, this study aimed to explore whether miR-326 could influence neuron apoptosis in AD mice and how miR-326 functions in this process. The candidate differentially expressed gene VAV1 was obtained by microarray analysis, and miRNAs that could regulate VAV1 candidate gene were predicted. Luciferase activity determination confirmed VAV1 as a target gene of miR-326. AD mice models were established for investigating the effect of miR-326 on AD mice. The overexpression of miR-326 contributed to decreased time of the mice to find the platform and the escape latency and increased residence time on the target area. Besides, elevation of miR-326 decreased Aβ deposition and contents of Aβ_1-40 and Aβ_1-42 . Moreover, miR-326 overexpression increased neuron cell ability, mediated cell entry, and inhibited neuron apoptosis via JNK signaling pathway. Of crucial importance, miR-326 negatively regulated the expression of VAV1, inhibited tau phosphorylation, and blocked the activation of the JNK signaling pathway. Taken together these observations, we demonstrate that miR-326 improves cognitive function of AD mice and inhibits neuron apoptosis in AD mice through inactivation of the JNK signaling pathway by targeting VAV1. Based on those findings, miR-326 might exert promise as target for the treatment of AD.

Protective effects of microRNA-330 on amyloid β-protein production, oxidative stress, and mitochondrial dysfunction in Alzheimer's disease by targeting VAV1 via the MAPK signaling pathway

This study aims to explore the effect of miR-330 targeting VAV1 on amyloid β-protein (Aβ) production, oxidative stress (OS), and mitochondrial dysfunction in Alzheimer's disease (AD) mice through the MAPK signaling pathway. Putative targeted gene of miR-330 was performed by a miRNA target prediction website and dual-luciferase reporter gene assay. AD mouse model was successfully established. Fourteen C57 mice were randomized into AD and control groups. The positive protein expression rate of VAV1 was measured by immunohistochemistry. Neuron cells were assigned into control, blank, negative control (NC), miR-330 mimics, miR-330 inhibitors, siRNA-VAV1, and miR-330 inhibitors + siRNA-VAV1 groups. Expression of miR-330, VAV1, ERK1, JNK1, P38MAPK, Aβ, COX, and lipoprotein receptor-related protein-1 (LRP-1) were determined using RT-qPCR and Western blotting. Colorimetry was applied to measure the levels of OS parameters of superoxide dismutase (SOD) and malondialdehyde (MDA). Aβ production in brain tissue was detected using ELISA, while that in neuron cell was measured by radioimmunoassay. MiR-330 was down-regulated in neuron cells of AD mice and VAV1 was negatively regulated by miR-330. Compared with the control group, the positive protein expression rate of VAV1 was significantly elevated in the AD group. Overexpression of miR-330 decreased the expression of VAV1, ERK1, JNK1, P38MAPK, and Aβ, but increased the expression of COX and LRP-1. AD mice revealed elevated Aβ production and MDA with decreased SOD level. The result indicates that overexpressed miR-330 targeting VAV1 through the MAPK signaling pathway reduces Aβ production and alleviates OS and mitochondrial dysfunction in AD.

Activating mutations and translocations in the guanine exchange factor VAV1 in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis and for which genetic mechanisms of transformation remain incompletely understood. Using RNA sequencing and targeted sequencing, here we identify a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7) in PTCL. Mechanistically these genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support a driver oncogenic role for VAV1 signaling in the pathogenesis of PTCL.

Genetic alterations affecting GTPases and T-cell receptor signaling in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are rare, heterogeneous tumors with poor response to standard therapy and few targeted treatments available. The identification of mutations in the T-cell receptor (TCR) signaling pathway that either directly or indirectly affect Ras- and Rho-family GTPases is an emerging theme across PTCL subtypes. This review summarizes the role of GTPases in TCR signaling and highlights the constellation of mutations in this pathway among PTCLs. In particular, focus is given to the functional impact of the mutations and opportunities for targeted therapy. These mutations include activating mutations and gene fusions involving the guanine nucleotide exchange factor, VAV1, as well as activating and dominant negative mutations in the GTPases KRAS and RHOA, respectively. In addition to mutations directly affecting the GTPase pathway, TCR signaling mutations indirectly affecting Ras- and Rho-family GTPases involving genes such as CD28, FYN, LCK, and PLCG1 are also reviewed.

EphB4-VAV1 signaling pathway is associated with imatinib resistance in chronic myeloid leukemia cells

Imatinib (IM) resistant Chronic Myeloid Leukemia (CML) is an important issue to be addressed while treating CML patients. The present study analyzes the role of EphB4-VAV1 signaling in IM-resistant CML. EphB4 and VAV1 were overexpressed in IM-resistant CML patients and K562-R cell line (K562-R). Then, we established stable under-expressing EphB4 cell line K562-R-EphB4-sh. VAV1 was down-regulated in K562-R-EphB4-sh cells. K562-R-EphB4-sh cells gained re-sensitivity to IM and K562-R cells showed mild IM resistance. However, EphB4 was no changed when the VAV1 was down-regulated. EphB4 and VAV1 were overexpressed in IM-resistant CML, VAV1might be the downstream moleculars of EphB4. These results suggest a potential role of EphB4-VAV1 signaling as therapeutic target of IM-resistant CML.