transforming-growth-factor-beta and Paraparesis--Tropical-Spastic

HTLV-1 Tax expression exerts an inhibitory effect on the Foxp3 transcription factor in CD4(+)CD25(+) T-regulatory cells (Treg). For a better understanding of the role of Tax mRNA in the gene expression of cellular markers we measured Tax, Foxp3, CTLA-4, GITR, TGF-β, and IL-10 mRNA in Treg cells of 50 patients with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP; 27 women and 23 men; mean age: 56.7 years). The control group consisted of 23 non-infected subjects (12 women and 11 men) with a mean age of 51.3 years. Real-time PCR was used to measure mRNA of Tax proteins and several cellular markers of Treg function. Determinations revealed a high level of Tax mRNA in HAM/TSP (124.35 copies/100 CD4(+)CD25(+) T cells). Foxp3, GITR, and CTLA-4 mRNA levels were lower in HAM/TSP patients (mean ± SD, 22.07 ± 0.78, 9.63 ± 0.36, and 4.54 ± 0.39, respectively) than in non-infected controls (47.15 ± 12.94, 22.14 ± 1.91, and 21.07 ± 2.31). Both groups had similar levels of TGF-β and IL-10. An inverse relationship was found between Tax levels and Foxp3, CTLA-4, and GITR levels. Conversely, there was a direct correlation between levels of Foxp3, GITR, and CTLA-4. Disease severity and evolution time did not correlate with Tax or Foxp3 levels. The present results suggest that Tax and Foxp3 mRNA vary with the same degree of disease severity in HAM/TSP patients. Tax fluctuations may affect CTLA-4 and GITR expression via the Foxp3 pathway, causing virus-induced dysfunction of CD4(+)CD25(+) T cells in HAM/TSP patients.

Topics: Adult; Aged; Biomarkers; Case-Control Studies; CD4-Positive T-Lymphocytes; CTLA-4 Antigen; Female; Forkhead Transcription Factors; Gene Products, tax; Glucocorticoid-Induced TNFR-Related Protein; Human T-lymphotropic virus 1; Humans; Male; Middle Aged; Paraparesis, Tropical Spastic; Real-Time Polymerase Chain Reaction; RNA, Messenger; Severity of Illness Index; Transforming Growth Factor beta

We previously demonstrated that CD4(+)CD25(+) T regulatory cells (Tregs), important for the maintenance of immune tolerance and prevention of autoimmune disease, from patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) exhibit reduced Foxp3 expression and Treg suppressor function compared with healthy donors. Since TGF-beta signaling has been previously reported to be critical for both Foxp3 expression and Treg function, we examined whether this signaling pathway was dysregulated in patients with HAM/TSP. Levels of TGF-beta receptor II (TGF-betaRII) as well as Smad7 (a TGF-beta-inducible gene) were significantly reduced in CD4(+) T cells in patients with HAM/TSP compared with healthy donors, and the expression of TGF-betaRII inversely correlated with the HTLV-I tax proviral load. Importantly, both CD4(+)CD25(+) and CD4(+)CD25(-) T cells from HAM/TSP patients exhibited reduced TGF-betaRII expression compared with healthy donors, which was associated with functional deficits in vitro, including a block in TGF-beta-inducible Foxp3 expression that inversely correlated with the HTLV-I tax proviral load, loss of Treg suppressor function, and escape of effector T cells from Treg-mediated control. This evidence suggests that a virus-induced breakdown of immune tolerance affecting both regulatory and effector T cells contributes to the pathogenesis of HAM/TSP.

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Forkhead Transcription Factors; Gene Products, tax; Human T-lymphotropic virus 1; Humans; Immune Tolerance; Liver Neoplasms; Paraparesis, Tropical Spastic; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad3 Protein; Smad4 Protein; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Human T lymphotropic virus-type 1 (HTLV-1) activates the immune system leading to a persistent and exacerbated T-cell response with increased production of IFN-gamma and TNF-alpha. Overproduction of pro-inflammatory cytokines is correlated with the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), although some HTLV-1 carriers also show high levels of these cytokines. In this study, the ability of regulatory cytokines and cytokine antagonists to inhibit spontaneous IFN-gamma production was investigated.. IFN-gamma levels were measured by ELISA before and after addition of cytokines or anti-cytokines.. Addition of IL-10 significantly reduced spontaneous IFN-gamma synthesis in cell cultures from HTLV-1 carriers, while no differences were observed in HAM/TSP patients. There was also a tendency to decreased IFN-gamma levels in cell cultures from HTLV-1 carriers with exogenous addition of TGF-beta. In paired analysis, neutralization of IL-2 significantly decreased IFN-gamma production in HTLV-1 carriers but not in HAM/TSP patients. Neutralization of IL-15 was less effective than neutralization of IL-2 in modulating IFN-gamma production. In HTLV-1 carriers, anti-IL-2 and simultaneous addition of anti-IL-2 and anti-IL-15 decreased IFN-gamma synthesis by 46 and 64%, respectively, whereas in patients with HAM/TSP simultaneous neutralization of both anti-cytokines only decrease IFN-gamma levels by 27%.. Although a large proportion of HTLV-1 carriers produced high levels of pro-inflammatory cytokines similar to those observed in HAM/TSP patients, immune response can be downregulated by cytokines or cytokine antagonists in most HTLV-1 carriers. This modulation can be an important step in the prevention of tissue damage and progression from the HTLV-1 carrier state to HAM/TSP.

Topics: Aged; Carrier State; Cells, Cultured; Disease Progression; Enzyme-Linked Immunosorbent Assay; Female; History, 16th Century; Human T-lymphotropic virus 1; Humans; Interferon-gamma; Interleukin-10; Interleukin-15; Interleukin-2; Male; Middle Aged; Paraparesis, Tropical Spastic; T-Lymphocytes; Transforming Growth Factor beta

DNA motifs that encode for specific transcriptional regulatory sequences (TRS) when engineered adjacent to the structural protein coding domain of a suicide enzyme can provide cell-lineage specific protein expression. The disparate up-regulation of several genes in adult T-cell leukemia (ATL) versus HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), seropositive carriers (SPC) and uninfected normals may reflect events at the molecular level related to leukemogenesis or to processes maintaining the heme-oncologic phenotype. Further, the genetic transduction of cytokine and receptor genes uniquely associated with ATL may provide targets for the development of leukemia-specific gene therapies aimed at exploiting differences in the production of certain growth factors and growth factor receptors. Comparisons of the transcriptional and translational levels of interleukin-2 receptor alpha chain (IL-2R alpha), transforming growth factor-beta 1 (TGF-beta 1) and intracellular adhesion molecule-1 (ICAM-1) in ATL, HAM/TSP, and SPC and in several control populations revealed selectively up-regulated expression in ATL. We evaluated the feasibility of using lymphoid-specific TRS to activate herpes simplex virus thymidine kinase (HSVtk) to achieve selective cytotoxicity in leukemias expressing terminal deoxynucleotidyl transferase (TdT). Selective and efficient leukemic cell killing was produced and suggests that similar chimeric gene constructs containing TRS elements for IL-2R alpha, TGF-beta 1, or ICAM-1 may prove useful in designing gene therapies to treat ATL.

Topics: Adult; Carrier State; Cytokines; Gene Expression Regulation, Neoplastic; Genetic Therapy; Humans; Intercellular Adhesion Molecule-1; Interleukins; Leukemia, T-Cell; Paraparesis, Tropical Spastic; Protein Engineering; Receptors, Cytokine; Receptors, Interleukin-2; Regulatory Sequences, Nucleic Acid; Simplexvirus; Thymidine Kinase; Transforming Growth Factor beta

While considerable information is available on the pathogenesis of human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), fundamental questions remain unanswered. In particular the clinicopathological uniformity of the disorder among patients remains poorly understood. The potential role of TGF-beta as a preferential immune regulator in the CNS and the functional heterogeneity of TGF-beta has led us to assess the possible involvement of this cytokine in the pathogenic process. To investigate this, the modulatory effects of TGF-beta 1 on HTLV-I-induced in vitro phenomena were evaluated using fractionated lymphocytes from patients with HAM/TSP. It could be shown that the proliferative response of CD8+ cells against cultured and irradiated autologous CD4+ cells possessing HTLV-I antigens was significantly inhibited by TGF-beta 1. However, the in vitro activation of HTLV-I, which was evaluated by spontaneous proliferation of CD4+ cells, was unaffected by TGF-beta 1. The induction of intracytoplasmic HTLV-I antigens in cultured CD4+ cells was facilitated by TGF-beta 1 in a dose-dependent manner. These findings suggest that TGF-beta may have a critical role in localized viral activation within the CNS in patients with HAM/TSP.

Topics: Adult; Aged; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Line; Cells, Cultured; Female; Human T-lymphotropic virus 1; Humans; Lymphocyte Activation; Male; Middle Aged; Paraparesis, Tropical Spastic; Transforming Growth Factor beta; Virus Activation

Immunocytochemical staining of spinal cords from five autopsied patients with HTLV-I-associated myelopathy/tropical spastic paraparesis was performed using a panel of monoclonal or polyclonal antibodies reactive with interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), tumor necrosis factor (TNF)-alpha, interferon (IFN)-alpha, IFN-beta, IFN-gamma and transforming growth factor (TGF)-beta. In the spinal cords of patients with a shorter duration of illness, IL-1 beta, TNF-alpha, and IFN-gamma were expressed on perivascular infiltrating macrophages, astrocytes and microglia in active-chronic inflammatory lesions. In striking contrast, we rarely noted cytokine expression except for IFN-gamma in inactive-chronic lesions of patients with longer durations. In situ expression of these cytokines on microglia and astrocytes, in addition to infiltrating mononuclear cells, suggests that glial cells participate in the inflammatory process, especially in active lesions. In addition, the cytokine expression was gradually downregulated along with duration of illness.

Topics: Aged; Animals; Antibodies; Antibodies, Monoclonal; Autopsy; Cytokines; Female; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Immunoglobulin G; Immunohistochemistry; Inflammation; Interferon-alpha; Interferon-beta; Interferon-gamma; Interleukin-1; Interleukin-6; Male; Mice; Middle Aged; Paraparesis, Tropical Spastic; Rabbits; Spinal Cord; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The human T-cell lymphotropic virus type I (HTLV-I) is capable of inducing a variety of host cellular genes including many of the cytokines responsible for immune regulation and osteoclast activation. This derangement in cytokine expression may contribute to the panoply of disease states associated with HTLV-I infection such as the adult T-cell leukemia (ATL) and HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). We wished to determine if there was a correlation between the expression of an array of cytokines and the diverse clinical manifestations of ATL and HAM/TSP. Utilizing the techniques of specific mRNA amplification by the polymerase chain reaction (PCR) as well as Northern blotting, we analyzed the ex vivo mRNA expression of gamma-interferon (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and transforming growth factor-beta 1 (TGF-beta 1) in the peripheral blood of HAM/TSP and ATL patients as well as asymptomatic seropositive carriers. IFN-gamma, TNF-alpha, and IL-1 beta transcripts were up-regulated in patients with HAM/TSP and seropositive carriers when compared to their levels in ATL and normal controls. In contrast, the ATL patients constitutively expressed higher levels of TGF-beta 1 mRNA than HAM/TSP and seropositive carriers. In addition, TNF-alpha and IL-1 beta serum levels were elevated in HAM/TSP, but not in ATL patients nor seropositive carriers. However, the circulating leukemic cells from ATL patients secreted increased levels of TGF-beta 1 protein into the culture medium than T-cells derived from HAM/TSP patients. Collectively these results suggest that induction of IFN-gamma, TNF-alpha, and IL-1 beta in HAM/TSP may initiate an inflammatory cascade with subsequent events leading to immune mediated destruction of the central nervous system in these patients. Expression of osteoclast activators such as TNF-alpha and IL-1 beta is not associated with hypercalcemia in ATL. Finally, impaired cellular and humoral immune responses present in ATL, but not in HAM/TSP, may be related to elevated levels of TGF-beta 1 produced by the leukemic cells. These differences in retroviral-induced host cytokine expression in ATL and HAM/TSP suggest alternate roles in disease pathogenesis.

Topics: Adult; Base Sequence; Central Nervous System; Cytokines; DNA, Single-Stranded; Female; Gene Expression Regulation, Viral; Humans; Interferon-gamma; Interleukin-1; Leukemia, T-Cell; Male; Middle Aged; Molecular Sequence Data; Paraparesis, Tropical Spastic; Polymerase Chain Reaction; Retroviridae; RNA, Messenger; T-Lymphocytes; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Up-Regulation