scholarly journals Elucidating the basis for permissivity of the MT-4 T-cell line to replication of an HIV-1 mutant lacking the gp41 cytoplasmic tail

2020 ◽  
Author(s):  
Melissa V. Fernandez ◽  
Huxley K. Hoffman ◽  
Nairi Pezeshkian ◽  
Philip R. Tedbury ◽  
Schuyler B. van Engelenburg ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Viral Transmission ◽  
Virus Particles ◽  
Cell Transmission ◽  
T Cell Lines ◽  
Hiv 1

AbstractHIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study we investigated the viral and cellular factors that contribute to the permissivity of MT-4 to gp41 CT truncation. We found that the kinetics of HIV-1 production are faster in MT-4 than in the other T-cell lines tested, but MT-4 express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 express higher levels of plasma-membrane-associated Env than non-permissive cells and Env internalization from the plasma membrane is slower compared to another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4, two-fold less Env is incorporated into virus particles in MT-4 compared to SupT1. Cell-to-cell transmission between co-cultured 293T and MT-4 is higher than in co-cultures of 293T with most other T-cell lines tested, indicating that MT-4 are highly susceptible to this mode of infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines.ImportanceThe HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to non-permissive cells.

scholarly journals Elucidating the Basis for Permissivity of the MT-4 T-Cell Line to Replication of an HIV-1 Mutant Lacking the gp41 Cytoplasmic Tail

2020 ◽  
Vol 94 (23) ◽  
Author(s):  
Melissa V. Fernandez ◽  
Huxley K. Hoffman ◽  
Nairi Pezeshkian ◽  
Philip R. Tedbury ◽  
Schuyler B. van Engelenburg ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Viral Transmission ◽  
Virus Particles ◽  
T Cell Lines ◽  
Hiv 1

ABSTRACT HIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study, we investigated the viral and cellular factors that contribute to the permissivity of MT-4 cells to gp41 CT truncation. We found that the kinetics of HIV-1 production and virus release are faster in MT-4 than in the other T-cell lines tested, but MT-4 cells express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 cells express higher levels of plasma-membrane-associated Env than nonpermissive cells, and Env internalization from the plasma membrane is less efficient than that from another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4 cells, 2-fold less Env is incorporated into virus particles produced from MT-4 than SupT1 cells. Contact-dependent transmission between cocultured 293T and MT-4 cells is higher than in cocultures of 293T with most other T-cell lines tested, indicating that MT-4 cells are highly susceptible to cell-to-cell infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines. IMPORTANCE The HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 cells is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to nonpermissive cells.

Cell-Surface Heparan Sulfate Proteoglycan Mediates HIV-1 Infection of T-Cell Lines

1993 ◽  
Vol 9 (2) ◽  
pp. 167-174 ◽  
Author(s):  
MAHESH PATEL ◽  
MASAKI YANAGISHITA ◽  
GREGORY RODERIQUEZ ◽  
DUMITH CHEQUER BOU-HABIB ◽  
TAMAS ORAVECZ ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
Heparan Sulfate ◽  
Cell Lines ◽  
Heparan Sulfate Proteoglycan ◽  
Sulfate Proteoglycan ◽  
T Cell Lines ◽  
Hiv 1

scholarly journals Role of mitochondrial glucocorticoid receptor in glucocorticoid-induced apoptosis

2006 ◽  
Vol 203 (1) ◽  
pp. 189-201 ◽  
Author(s):  
Ronit Vogt Sionov ◽  
Orly Cohen ◽  
Shlomit Kfir ◽  
Yael Zilberman ◽  
Eitan Yefenof
Keyword(s):  
T Cell ◽  
Glucocorticoid Receptor ◽  
Cell Lines ◽  
Cell Types ◽  
Thymic Epithelial Cells ◽  
Dependent Manner ◽  
Localization Signal ◽  
Induced Apoptosis ◽  
T Cell Lines

The mechanisms by which glucocorticoid receptor (GR) mediates glucocorticoid (GC)-induced apoptosis are unknown. We studied the role of mitochondrial GR in this process. Dexamethasone induces GR translocation to the mitochondria in GC-sensitive, but not in GC-resistant, T cell lines. In contrast, nuclear GR translocation occurs in all cell types. Thymic epithelial cells, which cause apoptosis of the PD1.6 T cell line in a GR-dependent manner, induce GR translocation to the mitochondria, but not to the nucleus, suggesting a role for mitochondrial GR in eliciting apoptosis. This hypothesis is corroborated by the finding that a GR variant exclusively expressed in the mitochondria elicits apoptosis of several cancer cell lines. A putative mitochondrial localization signal was defined to amino acids 558–580 of human GR, which lies within the NH2-terminal part of the ligand-binding domain. Altogether, our data show that mitochondrial and nuclear translocations of GR are differentially regulated, and that mitochondrial GR translocation correlates with susceptibility to GC-induced apoptosis.

scholarly journals Interleukin 2 induces antigen-reactive T cell lines to secrete BCGF-I.

1983 ◽  
Vol 158 (6) ◽  
pp. 2024-2039 ◽  
Author(s):  
M Howard ◽  
L Matis ◽  
T R Malek ◽  
E Shevach ◽  
W Kell ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Interleukin 2 ◽  
Activated T Lymphocytes ◽  
T Cell Lines ◽  
Activated B Cells

Antigen-activated T lymphocytes produce within 24 h of stimulation a factor that is indistinguishable biochemically and functionally from the B cell co-stimulating growth factor, BCGF-I, originally identified in induced EL4 supernatants: Supernatants from antigen-stimulated T cell lines are not directly mitogenic for resting B cells, but synergize in an H-2-unrestricted manner with anti-Ig activated B cells to produce polyclonal proliferation but not antibody-forming-cell development; biochemical studies reveal the B cell co-stimulating factor present in antigen-stimulated T cell line supernatants is identical by phenyl Sepharose chromatography and isoelectric focusing (IEF) to EL4 supernatant BCGF-I. We thus conclude that normal T cells produce BCGF-I in response to antigenic stimulation. Analysis of the mechanism of BCGF-I production by antigen-stimulated T cells showed that optimum amounts of BCGF-I were obtained as quickly as 24 h post-stimulation, and that the factor producing cells in the T cell line investigated bore the Lyt-1+2- phenotype. As few as 10(4) T cells produced sufficient BCGF-I to support the proliferation of 5 X 10(4) purified anti-Ig activated B cells. Finally, the activation of normal T cell lines to produce BCGF-I required either antigen presented in the context of syngeneic antigen-presenting cells (APC) or interleukin 2 (IL-2).

Evidence for Cooperation of Receptor Tyrosine Kinases and Activating NOTCH Mutations to Hyperactivate mTOR in T-Cell Leukemia: A Rationale Basis for Targeted Therapy

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1381-1381
Author(s):  
Adrian Schwarzer ◽  
Johann Meyer ◽  
Martijn Brugman ◽  
Axel Schambach ◽  
Martin Stanulla ◽  
...  
Keyword(s):  
T Cell ◽  
Tyrosine Kinase ◽  
Cell Line ◽  
Cell Lines ◽  
Microarray Analysis ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Akt Activation ◽  
Rtk Signaling

Abstract Abstract 1381 T-cell acute lymphoblastic leukemia (T-ALL) remains a therapeutic challenge. T-ALLs are characterized by recurring chromosomal rearrangements causing aberrant expression of transcription factors (Myb; TAL/SCL; HOX) dividing patients into different subgroups. Activating mutations in NOTCH, the master regulator of T-cell development, are found in more than 60% of T-ALLs independently of subtype. Most T-ALLs display a hyperactivation of the PI3K-AKT-mTOR pathway, a potential target for therapeutic intervention. The master regulator of PI3K-AKT signalling is PTEN, which is frequently inactivated in cancer. Recent data suggests that complete PTEN loss due to mutation is rare in primary human T-ALL, whereas PTEN-inhibiting posttranslational modifications are more common (Barata et al., J. Clin. Invest. 2008, 118). As these modifications decrease, but do not abolish the phosphatase activity of PTEN, we hypothesized that further input from tyrosine kinases, particularly receptor tyrosine kinases (RTK), may be needed to sustain PI3K-AKT-mTOR activation. In order to investigate how RTK-signaling may contribute to the pathogenesis of T-ALL we used an established murine bone marrow transplantation model (Li et al. Blood 2009, 113). To mimic tyrosine-kinase signaling we expressed δTrkA, a constitutively active TRKA receptor tyrosine kinase (TRK =tropomyosin-related kinase) from gammaretroviral or lentiviral vectors in c-kit+ Sca-1+ Lin− (KSL) cells. Intravenous injection of δTrkA-transduced hematopoietic cells in C57BL6 mice (n=10) induced transplantable T-ALL with a latency of about 120 days. The resulting T-ALLs could be propagated in culture as clonal cell lines. Signaling studies showed that δTRKA activates predominantly ERK upon expression in murine hematopoietic cell lines. However, the obtained δTRKA+ T-ALL lines (n=7) showed a profound shift in the use of downstream signaling cascades, displaying a very high activation of AKT-mTOR and absent ERK phosphorylation, resembling human T-ALL. High AKT activation was uniformly detected regardless of PTEN protein expression in all but one T-ALL (#003). To understand the rewired signaling network we looked for a potential contribution of insertional mutagenesis and chromosomal aberrations. Array-CGH showed homozygous deletions on chr14c2 involving the T-cell receptor alpha and delta genes in 3/3 cell lines and heterozygous deletions in Ikzf1 in 2/3 cell lines. Viral integration sites showed no common insertion pattern and no insertion in genes implicated in RTK-signaling. The expression of genes in proximity to viral integrations (±500 kb) appeared unaltered as determined by cDNA-microarray analysis of the T-ALL cell line #483 against wild type CD4+CD8+ thymocytes. Microarray analysis revealed enrichment of Notch1 target genes in the T-ALL cell line #483. Sequencing of Notch1 revealed both, PEST domain mutations and the recently described (Aster et al, Blood 2010, 116) RAG mediated 5'-deletions in cis, in all but one investigated T-ALL. Northern and Western Blots confirmed the expression of truncated Notch1 transcripts and protein, respectively. The one cell line (#003) which retained the original δTrkA signaling pattern had no Notch mutation and could only be cultured on OP9-Delta-like-1 stroma cells, highlighting the importance of Notch signaling. As this cell line was established from a mouse displaying an enlarged thymus, but no full manifestation of T-ALL, our data suggests that acquisition of Notch mutations is a late, but necessary step required for overt leukemia, whereas the initiating events may arise in kinase signaling pathways of prethymic progenitors. All T-ALL cell lines were sensitive to mTOR or Notch inhibition with Rapamycin or Compound E, respectively. Finally, we used phosphoprotein-arrays to monitor the phosphorylation of 42 RTK in childhood T-ALL samples with different activating NOTCH mutations (n=5) and detected several activated RTK (e.g. MSPR, FGFR, ErbB4, VEGFR) in the patient samples. Taken together, our findings suggest a cooperation of RTK and activating NOTCH mutations in mTOR activation seen in T-ALL and encourage further investigation of 1) aberrant RTK-signaling in T-ALL 2) the role of RTK activation in creating a preleukemic cell clone, 3) evaluation of combined therapy targeting RTKs and NOTCH, and 4) the role of activated NOTCH on mTORC2-AKT activation independently of PTEN. Disclosures: Baum: Patent office: Patents & Royalties.

scholarly journals Differential Role of PKC-Induced c-Jun in HTLV-1 LTR Activation by 12-O-Tetradecanoylphorbol-13-acetate in Different Human T-cell Lines

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e29934 ◽  
Author(s):  
Ammar Abou-Kandil ◽  
Rachel Chamias ◽  
Mahmoud Huleihel ◽  
W. T. Godbey ◽  
Mordechai Aboud
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Human T Cell ◽  
T Cell Lines

scholarly journals Identification of an env-defective HIV-1 mutant capable of spontaneous reversion to a wild-type phenotype in certain T-cell lines

2014 ◽  
Vol 11 (1) ◽  
pp. 177 ◽  
Author(s):  
Yudong Quan ◽  
Hongtao Xu ◽  
Victor G Kramer ◽  
Yingshan Han ◽  
Richard D Sloan ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Wild Type ◽  
Spontaneous Reversion ◽  
Wild Type Phenotype ◽  
T Cell Lines ◽  
Hiv 1

High-throughput sequencing identifies HIV-1-replication- and latency-related miRNAs in CD4+ T cell lines

2017 ◽  
Vol 162 (7) ◽  
pp. 1933-1942 ◽  
Author(s):  
Xiangyun Lu ◽  
Jin Yang ◽  
Haibo Wu ◽  
Zongxing Yang ◽  
Changzhong Jin ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Cd4 T Cell ◽  
T Cell Lines ◽  
Hiv 1
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