23 research outputs found
PIM kinases facilitate lentiviral evasion from SAMHD1 restriction via Vpx phosphorylation
Lentiviruses have evolved to acquire an auxiliary protein Vpx to counteract the intrinsic host restriction factor SAMHD1. Although Vpx is phosphorylated, it remains unclear whether such phosphorylation indeed regulates its activity toward SAMHD1. Here we identify the PIM family of serine/threonine protein kinases as the factors responsible for the phosphorylation of Vpx and the promotion of Vpx-mediated SAMHD1 counteraction. Integrated proteomics and subsequent functional analysis reveal that PIM family kinases, PIM1 and PIM3, phosphorylate HIV-2 Vpx at Ser13 and stabilize the interaction of Vpx with SAMHD1 thereby promoting ubiquitin-mediated proteolysis of SAMHD1. Inhibition of the PIM kinases promotes the antiviral activity of SAMHD1, ultimately reducing viral replication. Our results highlight a new mode of virus–host cell interaction in which host PIM kinases facilitate promotion of viral infectivity by counteracting the host antiviral system, and suggest a novel therapeutic strategy involving restoration of SAMHD1-mediated antiviral response
Mediums for narration of the great achievements of Kobo-daishi : focus on the picture scroll, the printed books, and the Mandara
Three-dimensional MR imaging of the breast in supine position using a flexible surface coil: Value in the planning of the breast conserving surgery
Generation and Utilization of a Monoclonal Antibody against Hepatitis B Virus Core Protein for a Comprehensive Interactome Analysis
Hepatitis B virus (HBV) core antigen (HBc) is a structural protein that forms the viral nucleocapsid and is involved in various steps of the viral replication cycle, but its role in the pathogenesis of HBV infection is still elusive. In this study, we generated a mouse monoclonal antibody (mAb) against HBc and used it in antibody-based in situ biotinylation analysis in order to identify host proteins that interact with HBc. HBc antigen was produced with a wheat germ cell-free protein synthesis system and used to immunize mice. Among the established hybridoma clones, a single clone (mAb #7) was selected and further characterized for its ability in the antibody-based in situ biotinylation analysis to collect host proteins that are in the vicinity of HBc. Using mass spectrometry, we identified 215 HBc-interacting host proteins, three of which bind HBc most significantly under hypoxic conditions. Our results indicate that mAb #7 can be used to systematically identify host proteins that interact with HBc under pathophysiological conditions, and thus may be useful to explore the molecular pathways involved in HBV-induced cytopathogenesis
Identification of Tyrosine-Phosphorylated Proteins Upregulated during Epithelial–Mesenchymal Transition Induced with TGF‑β
The
epithelial-to-mesenchymal transition (EMT) is a unique process
for the phenotypic changes of tumor cells characterized by a transition
from polarized rigid epithelial cells to migrant mesenchymal cells,
thus conferring the ability of tumor invasion and metastasis. A major
challenge in the treatment of lung adenocarcinoma is to identify early
stage patients at a high risk of recurrence or metastasis, thereby
permitting the best therapeutic strategy and prognosis. In this study,
we used a transforming growth factor-β (TGF-β)-induced
EMT model to quantitatively identify protein tyrosine phosphorylation
during the course of EMT in relation to malignant characteristics
of lung adenocarcinoma cells. We performed relative quantitation analysis
of tyrosine-phosphorylated peptides in TGF-β-treated and -untreated
lung adenocarcinoma cells and identified tyrosine-phosphorylated proteins
that were upregulated in TGF-β-treated cells. These include
tensin-1 (TNS1) phosphorylated on Y1404, hepatocyte growth factor
receptor (c-Met) phosphorylated on Y1234, and NT-3 growth factor receptor
(TrkC) phosphorylated on Y516. We also found that these protein phosphorylation
profiles were specifically observed in tissue samples of patients
with poor prognostic lung adenocarcinoma. Tyrosine phosphorylations
of these proteins represent possible candidates of prognostic prediction
markers for lung adenocarcinoma
Development of a Monoclonal Antibody Targeting HTLV-1 Envelope gp46 Glycoprotein and Its Application to Near-Infrared Photoimmuno-Antimicrobial Strategy
Human T-cell leukemia virus type 1 (HTLV-1), a retrovirus, causes adult T-cell leukemia-lymphoma, HTLV-1 associated myelopathy/tropical spastic paraparesis, and HTLV-1 uveitis. Currently, no antiretroviral therapies or vaccines are available for HTLV-1 infection. This study aimed to develop an antibody against the HTLV-1 envelope protein (Env) and apply it to a near-infrared photoimmuno-antimicrobial strategy (NIR-PIAS) to eliminate HTLV-1 infected cells. We established mouse monoclonal antibodies (mAbs) against HTLV-1 Env by immunization with a complex of liposome and the recombinant protein. Detailed epitope mapping revealed that one of the mAbs bound to the proline-rich region of gp46 and exhibited no obvious neutralizing activity to inhibit viral infection. Instead, the mAb was rarely internalized intracellularly and remained on the cell surface of HTLV-1-infected cells. The antibody conjugated to the photosensitive dye IRDye700Dx recognized HTLV-1 infected cells and killed them following NIR irradiation. These results suggest that the novel mAb and NIR-PIAS could be developed as a new targeted therapeutic tool against HTLV-1 infected cells
Image2_Development of a contacting transwell co-culture system for the in vitro propagation of primary central nervous system lymphoma.jpeg
Primary central nervous system lymphoma (PCNSL) is a malignant neoplasm of the central nervous system that is refractory to treatment and has extremely poor prognosis. One factor hindering the development of therapeutic options for PCNSL is its molecular heterogeneity and the extreme difficulty in establishing in vitro cell lines that permit intensive research on this disease. In the present study, we developed a method to propagate PCNSL cells in vitro using a contacting transwell cell culture system involving brain vascular pericytes. The co-culture system was found to recapitulate the tumor microenvironment that is influenced by the biological activity of adjacent pericytes, and to sustain the survival and proliferation of PCNSL cells in vitro. We further delineated the underlying molecular mechanisms and found that the HGF–c-Met axis may be involved in the long-term in vitro culture of PCNSL cells. Moreover, the peptidylprolyl isomerase Pin1 was found to play a key role in PCNSL cell survival and it sustained proliferation through interactions with key transcription factors related to B-cell lymphomagenesis. These results suggest that our in vitro co-culture system is well suited to analyzing the biological and molecular characteristics of PCNSL, and may contribute to the discovery of new therapeutic interventions.</p
Image4_Development of a contacting transwell co-culture system for the in vitro propagation of primary central nervous system lymphoma.jpeg
Primary central nervous system lymphoma (PCNSL) is a malignant neoplasm of the central nervous system that is refractory to treatment and has extremely poor prognosis. One factor hindering the development of therapeutic options for PCNSL is its molecular heterogeneity and the extreme difficulty in establishing in vitro cell lines that permit intensive research on this disease. In the present study, we developed a method to propagate PCNSL cells in vitro using a contacting transwell cell culture system involving brain vascular pericytes. The co-culture system was found to recapitulate the tumor microenvironment that is influenced by the biological activity of adjacent pericytes, and to sustain the survival and proliferation of PCNSL cells in vitro. We further delineated the underlying molecular mechanisms and found that the HGF–c-Met axis may be involved in the long-term in vitro culture of PCNSL cells. Moreover, the peptidylprolyl isomerase Pin1 was found to play a key role in PCNSL cell survival and it sustained proliferation through interactions with key transcription factors related to B-cell lymphomagenesis. These results suggest that our in vitro co-culture system is well suited to analyzing the biological and molecular characteristics of PCNSL, and may contribute to the discovery of new therapeutic interventions.</p
Table1_Development of a contacting transwell co-culture system for the in vitro propagation of primary central nervous system lymphoma.pdf
Primary central nervous system lymphoma (PCNSL) is a malignant neoplasm of the central nervous system that is refractory to treatment and has extremely poor prognosis. One factor hindering the development of therapeutic options for PCNSL is its molecular heterogeneity and the extreme difficulty in establishing in vitro cell lines that permit intensive research on this disease. In the present study, we developed a method to propagate PCNSL cells in vitro using a contacting transwell cell culture system involving brain vascular pericytes. The co-culture system was found to recapitulate the tumor microenvironment that is influenced by the biological activity of adjacent pericytes, and to sustain the survival and proliferation of PCNSL cells in vitro. We further delineated the underlying molecular mechanisms and found that the HGF–c-Met axis may be involved in the long-term in vitro culture of PCNSL cells. Moreover, the peptidylprolyl isomerase Pin1 was found to play a key role in PCNSL cell survival and it sustained proliferation through interactions with key transcription factors related to B-cell lymphomagenesis. These results suggest that our in vitro co-culture system is well suited to analyzing the biological and molecular characteristics of PCNSL, and may contribute to the discovery of new therapeutic interventions.</p