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Shichijo, T.

Publications and source records attributed to Shichijo, T..

3 recordsLinked to original sources

Machine Learning-based Identification and Characterization of High-risk Carriers of HTLV-1-Associated Myelopathy (HAM)

HTLV-1-associated myelopathy (HAM) develops in a part of HTLV-1-infected individuals while most of the individuals remain asymptomatic. This complicates the identification of HTLV-1 carriers at elevated risk. In this study, we integrated HTLV-1 proviral load and antibody titers against Tax, Env, Gag p15, p19, and p24 proteins in a machine learning (ML) framework to identify and characterize high-risk individuals likely to develop HAM. We stratified asymptomatic carrier samples employing an anomaly detection model. We further developed and validated classifier models capable of distinguishing three clinical subgroups, carrier, ATL, and HAM for assessing the anomaly carrier samples as unseen test data. With most anomaly carrier samples ([~]76.47%) predicted as HAM, further statistical and interpretative analysis revealed the HAM-like characteristics of the anomaly carrier samples indicating elevated risk. Additionally, significant heterogeneity in immune response was observed among other asymptomatic carriers. Our machine learning-based approach offers a novel and insightful tool for identifying and evaluating high-risk characteristics for HAM, providing a holistic view of the complex immune dynamics of asymptomatic carriers of HTLV- 1.

systems biology↗

JunB-HBZ nuclear translocation by TGF-beta is a key driver in HTLV-1-mediated leukemogenesis

The HTLV-1 bZIP factor (HBZ) gene, which is the only viral gene conserved and consistently expressed in all adult T-cell leukemia-lymphoma (ATL) cases, is critical for ATL oncogenesis. Although HBZ protein is found in both the nucleus and the cytoplasm, the dynamics of HBZ protein localization and its contribution to oncogenesis have not been fully elucidated. In this study, we analyzed the subcellular expression pattern of HBZ in primary HTLV-1-infected T cells from asymptomatic carriers and leukemic cells of ATL patients using the Proximity Ligation Assay. Nuclear localization of HBZ protein was significantly higher in fresh ATL cells than in HTLV-1-infected cells from carriers. Importantly, translocation of HBZ protein from the cytoplasm to the nucleus after TGF-{beta} activation was observed in ATL patients, but not in HTLV-1 carriers. In ATL cells, the cellular transcription factors JunB and pSmad3 interact with HBZ and facilitate its nuclear translocation upon TGF-{beta} stimulation. JUNB knockdown inhibits cell proliferation in vitro and in vivo and promotes apoptosis in ATL cells but not in HTLV-1-infected non-leukemic cells, indicating that JunB has important roles in maintaining ATL cells. In conclusion, TGF-{beta}-induced nuclear translocation of HBZ-JunB complexes is associated with ATL oncogenesis.

microbiology↗

Reprogramming of lactate metabolism is linked to the oncogenesis of the virus-induced leukemia

Acceleration of glycolysis is a common trait of cancer. A key metabolite, lactate, is properly secreted from cancer cells, since its accumulation is toxic. Here, we report that a viral oncogene, HTLV-1 bZIP factor (HBZ), bimodally upregulates TAp73 to promote lactate excretion from adult T-cell leukemia-lymphoma (ATL) cells. HBZ protein binds to EZH2 and reduces its occupancy of the TAp73 promoter. Meanwhile, HBZ RNA activates TAp73 transcription via the BATF3-IRF4 machinery. TAp73 upregulates the lactate transporters MCT1 and MCT4. Inactivation of TAp73 leads to intracellular accumulation of lactate, inducing cell death in ATL cells. Furthermore, TAp73 knockout diminished development of inflammation in HBZ-transgenic mice. An MCT1/4 inhibitor, syrosingopine, decreased the growth of ATL cells in vitro and in vivo. MCT1/4 expression was positively correlated with TAp73 in many cancers, and their upregulations were associated with dismal prognosis. Activation of the TAp73-MCT1/4 pathway could be a common mechanism contributing to oncogenesis.

cancer biology↗