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Inhibition of ABL1 tyrosine kinase reduces HTLV-1 in peripheral blood mononuclear cells from HTLV-1-associated myelopathy/tropical spastic paraparesis patients

ABSTRACT: Human T-cell leukemia virus type 1 (HTLV-1) causes incurable adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Patients with HAM/TSP have increased levels of HTLV-1-infected cells compared with asymptomatic HTLV-1 carriers. However, the roles played by cellular genes in HTLV-1-infected CD4+ T cells await discovery. We combined microarray data and pathway analysis, and found that the ABL1 tyrosine kinase gene is a critical gene in HAM/TSP. ABL1 is a known survival factor for T- and B-lymphocytes. ABL1 is also part of the fused gene (BCR-ABL) known to be responsible for chronic myelogenous leukemia (CML), and tyrosine kinase inhibitors (TKI), including imatinib, nilotinib, and dasatinib, are in safe clinical use for treating CML. To evaluate whether ABL1 is indeed critical for the pathogenesis of HAM/TSP, we investigated the effect of ABL1 inhibitors on HTLV-1-infected cells. We developed a propidium monoazide-HTLV-1 viability quantitative PCR assay, which distinguishes DNA from live cells and DNA from dead cells. Using this method, we were able to measure the HTLV-1 proviral load (PVL) in live cells alone when peripheral blood mononuclear cells (PBMCs) from HAM/TSP cases were treated with TKI. Treating the PBMCs with nilotinib or dasatinib produced significant reductions in the PVL (21.0% and 17.5%, respectively) in live cells. Furthermore, a retrospective survey based on our clinical records found a rare case of HAM/TSP, where the patient also suffered from CML. The patient showed an 84.2% PVL reduction after CML treatment with imatinib. We conclude that inhibiting the ABL1 tyrosine kinase specifically reduced the PVL in PBMCs from patients with HAM/TSP, suggesting that ABL1 is a significant gene for the survival of HTLV-1-infected cells and that TKI may be a potential therapeutic agent for HAM/TSP.

ORGANISM(S): Homo sapiens

PROVIDER: GSE132666 | GEO | 2020/05/26

REPOSITORIES: GEO

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Project description:Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an inflammatory neurodegenerative disease that affects motor, urinary, intestinal, and sensory functions. Typically, HAM/TSP is slowly progressive, but it may vary from limited motor disability after decades (very slow progression) to loss of motor function in a few years from disease onset (rapid). In this study, we aimed to identify prognostic biomarkers for HAM/TSP to support patient management. Thus, proteomic analysis of the cerebrospinal fluid (CSF) was performed with samples from HTLV-1 asymptomatic carriers (AC) (n=13) and HAM/TSP patients (n=21) with rapid, typical, and very slow progression using quantitative label-free liquid chromatography/tandem mass spectrometry. Enrichment analyses were also carried out to identify key biological processes associated with distinct neurological conditions in HTLV-1 infection. Candidate biomarkers were validated by ELISA in paired CSF and serum samples, and samples from HTLV-1-seronegative individuals (n=9) were used as controls. CSF analysis identified 602 proteins. Leukocyte/cell activation, immune response processes and neurodegeneration pathways were enriched in rapid progressors. Conversely, HTLV-1 AC and HAM/TSP patients with typical and very slow progression had enriched processes for nervous system development. Differential expression analysis showed that soluble vascular cell adhesion molecule 1 (sVCAM-1), chitotriosidase 1 (CHIT1), and cathepsin C (CTSC) were upregulated in HAM/TSP. However, only CHIT1 was significantly elevated after validation, particularly in HAM/TSP rapid progressors. In contrast, none of these biomarkers were altered in serum. Additionally, CSF CHIT1 levels in HAM/TSP patients positively correlated with the speed of HAM/TSP progression, defined as points in the IPEC-2 HAM/TSP disability scale per year of disease, and with CSF levels of phosphorylated neurofilament heavy chain, neopterin, CXCL5, CXCL10, and CXCL11. In conclusion, higher CSF levels of CHIT1 were associated with HAM/TSP rapid progression and correlated with other biomarkers of neuroinflammation and neurodegeneration. Therefore, we propose CHIT1 as a surrogate CSF biomarker to identify HAM/TSP patients with a worse prognosis.

Project description:Infiltrating T-lymphocytes from the peripheral blood into the central nervous system (CNS) play a dynamic role in the development of a neurological immune-mediated diseases. HAM/TSP is a chronic progressive inflammatory neurological disorder associated with human T-cell lymphotropic virus type I (HTLV-I) infection. In this chronic myelopathy, virus-infected circulating T-cells infiltrate the CNS and an immune response is initiated against the components of CNS. As the HTLV-I proviral load (PVL) has been used as the best clinical marker for patient diagnostic with HAM/TSP, we hypothesized there might be a signature on T-cell receptor (TCR) clonal repertoire in these patients, which could distinguish HAM/TSP patients from the healthy population, as well as from patients with a more heterogeneous CNS-reactive inflammatory disease as multiple sclerosis (MS). With this in mind, we applied an innovative unbiased molecular technique – unique molecular identifier (UMI) library-strategy to investigate with high accuracy the TCR clonal repertoire by high throughput sequencing (HTS) technology. cDNA-TCR β-chain libraries were sequenced from 2 million peripheral mononuclear cells (PBMCs) in 14 HAM/TSP patients, 34 MS patients and 20 healthy controls (HC). To address whether the clonal expansion correlates with the patient’s PVL level, analysis of longitudinal TCR repertoire was performed in 2 HAM/TSP patients. Over 5.6 million TCR sequences were generated per sample on HiSeq 2500 Illumina system and analyzed through the molecular identifier groups-based error correction pipeline (MiGEC). Bioinformatic analysis showed that clones with more than 8 reads had a lower coefficient of variation (CV) and then could be used with confidence to evaluate the TCR clonal expansion. While HAM/TSP patients showed the higher clonal T-cell expansion compared to MS and HC, increase of the TCR clonal expansion was inversely correlated with the diversity of TCR repertoire in all subject’s group. In addition, correlation of the PVL with TCR clonal expansion was observed in HAM/TSP patients at longitudinal time-points. Surprisingly, MS patients showed a higher diversity of TCR repertoire along with a very slight clonal T-cell expansion in comparison to either HAM/TSP patients or HC. Despite of the higher TCR clonal expansion in HAM/TSP patients, a non-shared or “private” TCR repertoire was observed in these patients. No clones that shared the same CDR3 amino acid sequences were seen in HC and MS patients. However, a cluster of related CDR3 amino acid sequences were observed for 18 out of 34 MS patients when evaluated by phylogenetic tree analysis. It suggestes that a TCR-repertoire signature might characterize patients with MS. Our findings suggest that even though a unique TCR-b repertoire shapes the immune response in patients with neurological immune-mediated disease, a relatedness on clonal T-cell repertoire exist in MS.

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Inhibition of ABL1 tyrosine kinase reduces HTLV-1 in peripheral blood mononuclear cells from HTLV-1-associated myelopathy/tropical spastic paraparesis patients

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