ABSTRACT
Resumen Antecedentes: El virus linfotrópico T tipo I (HTLV-I) origina la paraparesia espástica tropical (PET) en el 3% de los infectados, afectando predominante mujeres. Excepcionalmente la PET puede asociar un síndrome vestibular central y atrofia cerebelosa. Propósito: Presentar un nuevo y excepcional caso de paraparesia espástica y atrofia cerebelosa. Sugerir una interpretación patogénica del predominio femenino en esta patología Paciente: Mujer de 20 años de talla baja y menuda, infectada con HTLV-I durante la lactancia. Aproximadamente a los 15 años inició un síndrome ataxo-espástico progresivo, con grave alteración de la marcha, posteriormente agregó daño cognitivo y atrofia cerebelosa en la RM. Se constató a su ingreso una elevada carga viral y altos niveles de proteína Tax. Fue tratada con 4 mg betametasona diarios durante 10 días, que mejoraron la marcha. Conclusión: La PET es una axonopatía de la vía motora central, originada por la crónica perturbación del transporte axoplásmico, atribuible a la presencia de elevados niveles de la proteína Tax del virus. Circunstancialmente este aumento de Tax logra dañar axones del centro oval (deterioro cognitivo) o del vermis cerebeloso (síndrome vestibular central). La PET afecta mayoritariamente a mujeres 3:1, prevalencia que hace aparecer a las mujeres con una mayor vulnerabilidad en su SNC. Sin embargo, esta aparente minusvalía, sería debida a un aumento en la concentración de Tax en el SNC de ellas, causado por la adversa relación entre peso corporal y cantidad absoluta de Tax, que fue evidente en nuestra paciente, quien dio la clave para esta hipótesis.
Background: Lymphotropic Virus Type I (HTLV-I) causes Tropical Spastic Paraparesis (PET) in 3% of infected patients; in whom have been described exceptionally associated a central vestibular syndrome and cerebellar atrophy. Those alterations of CNS are predominating in women. Purpose: To present a new case of the exceptional form of spastic paraparesis and cerebellar atrophy. To suggest a pathogenic interpretation of female predominance in this pathology Patient: A 20-year-old woman of small size, infected with HTLV-I during lactation. Approximately at 15 years of age he started a progressive ataxo-spastic syndrome, later cognitive damage and cerebellar atrophy were added. Upon admission, high viral load and high levels of Tax protein, leukemoid lymphocytes and Sicca syndrome were observed. Conclusion: PET is an axonopathy of the central motor pathway, originated by a chronic disturbance of axoplasmic transport, attributable to the action of elevated levels of Tax protein in the CNS. In addition axons of the oval center (cognitive impairment) or the cerebellar vermis (central vestibular syndrome) are occasionally damaged. Although PET mainly affects 3: 1 women, this prevalence increases in accordance with the increase of neurological damage. The apparent greater vulnerability of the CNS in women would be due to the higher concentration of Tax in the CNS of them, originated in the adverse relationship between body weight and absolute amount of Tax, which was evident in our patient, who gave the key to this hypothesis.
Subject(s)
Humans , Female , Adult , Atrophy , Axons , Syndrome , Human T-lymphotropic virus 1 , Paraparesis, Tropical SpasticABSTRACT
We studied the effect of celastrol on the proliferation and apoptosis of adult T-cell leukemia (ATL) cells. After treating adult T-cell leukemia cell lines with different concentrations of celastrol, we analyzed the cell proliferation by MTT and colony formation assays. Flow cytometry was conducted to detect cell apoptosis by Annexin V-FITC/PI staining. Western blotting and dual-luciferase reporter assay were done to study the mechanism how celastrol suppressed the growth of adult T-cell leukemia cells. Celastrol could significantly inhibit the proliferation of adult T-cell leukemia cells, and induce apoptosis of ATL cells. With the increase of the concentration of celastrol, the ratio of Bax/Bcl-2 protein was up-regulated. The Caspase-3/7 protein was cleaved and activated after treatment with celastrol. Moreover, the expression of HTLV-1-encoded viral protein Tax was significantly inhibited in the celastrol treated cells. Taken together, these results indicated that celastrol effectively inhibited the proliferation of adult T-cell leukemia cells by regulating the expression of Bcl-2 family protein, and induced cell apoptosis by activating Caspase dependent pathway. In addition, celastrol could inhibit the expression of viral protein Tax. This study will provide an experimental basis for the clinical application of celastrol in the treatment of adult T-cell leukemia.
ABSTRACT
Objective To explore the expression of early growth response gene-1 (EGR-1) in T cells that were positive for Tax protein of human T-cell leukemia virus type 1 (HTLV-1) and its possible reg-ulatory mechanism .Methods A series of expression structures carrying the regulatory elements of EGR-1 in different length and luciferase reporter genes were constructed .TaxP cells were transfected with the con-structs containing reporter genes and cultured with 5μmol/L of NF-κB inhibitor BAY 11-7082 or equal vol-ume of DMSO.After cultured for 24 hours the cells were collected to test the luciferase activity .BAY 11-7082 or equal volume of DMSO was added into the supernatant of TaxP cell culture to test the expression of EGR-1 protein by Western blot after 24 hours of culture .Tax and its mutants M22 and M47 were transfected into 293 T cells respectively to test the expression of EGR-1 protein by Western blot after 24 hours of culture . Results The expression structures carrying the regulatory elements of EGR-1 in different length and their mutants followed by luciferase reporter genes were successfully constructed .The luciferase activity in the cells transfected with the constructs containing the elements E 1 and E2 were higher than that transfected with E3, DelE and MutE, but the reporter gene expressions were decreased with the interference of BAY 11-7082 (P<0.01).However, there were no significant changes with the luciferase activity in the cells transfected by elements E3, DelE and MutE.Western blot analysis indicated that the expression of EGR-1 protein was significantly decreased with the interference of BAY 10-7082 .The expression of EGR-1 protein in M22 mu-tants-transfected 293 T cells were decreased significantly in comparison with those by wild type tax-and M47-transfected cells .Conclusion NF-κB was the key nuclear factor in regulating the expression of EGR-1 pro-tein in Tax-positive T cells .
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Objective To explore the regulatory effects of HTLV-1 ( human T-cell leukemia virus type 1 ) Tax protein on the expression of HMGB 1 ( high mobility group box 1 ) gene in T cells .Methods Total RNA and protein were extracted from Tax +-T cells ( TaxP ) , Tax--T cells ( TaxN ) and Jurkat cells which were stably transfected with pCMV-Tax and pCMV-Neo, respectively.Then, the expression levels of HMGB1 mRNA and protein in different CD 4+T cells were analyzed by real-time PCR and Western blot (WB).By using liposome-mediated method, pGL3-HMGB1-luc reporter genes and pGL3-neo-luc were tran-siently transfected into TaxP and TaxN cells and the basal transcriptional activity was observed in different T cells.Additionally, pCMV-Tax and pGL3-HMGB1-luc reporter genes were also co-transfected into Jurkat cells and the regulatory effects of Tax protein on HMGB 1 gene was detected .The chromatin immunoprecipi-tation (ChIP) assay was used to identify HMGB1 genomic sites directly targeted by Tax .Results The ex-pression levels of HMGB1 mRNA and protein in Tax+-T cells ( TaxP) were higher than those in Tax--T cells (TaxN).The transcription regulation trends for HMGB1 gene in TaxN and TaxP cells were similar but not identical in diverse T cells.pHLuc3 (containing -504-+83 HMGB1) showed the highest transcriptional ac-tivity of HMGB1 gene in both TaxP and TaxN cells , but HMGB1 transcriptional activity of pHLuc 6 in TaxP cells was significantly stronger than that in TaxN cells .Luciferase assays also showed that Tax protein promo-ted the transcription of HMGB1 gene in a dose-dependent manner .The ChIP assay further confirmed that Tax protein enriched at the HMGB1 region of -1163--1043.Conclusion The region of nt -504--383 is essen-tial for the basal promoter activity of -1163-+83 HMGB1 gene originated from pHLuc 6 reporter plasmid , and Tax protein enriched probably at the HMGB 1 site of -1163--1043 enhances HMGB1 transcription.
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Objective To study the effects of the adult T cell leukemia virus type 1(HTLV-1) Tax protein on T lymphocytes self-reactive growth hormone(GH). Methods The expression of the growth hormone protein was measured by Western blot in TaxP and TaxN cells, which expresses HTLV-1 Tax or no. The location of growth hormone in the TaxP and TaxN cells were detected by LSCM(laser scanning confocal microscope). The level of growth hormone mRNA in TaxP and TaxN cells was measured by RT-PCR. The pGL2-GH-luc was transfected in TaxN and TaxP cells by Tfx-50-mediated transfection to assay transcriptional activity. The pNF-κB-luc, pAP-1-luc and pNFAT-luc was transfected into TaxP cells with pcDNA3.0-GH by Tfx50 to test bioactivity of the nuclear transcription factors. Results The mRNA and protein expression of GH could be promoted significantly by Tax. Relative to the TaxN cells, the transcriptional activity of GH was significantly increased about 6.37 times in TaxP cells(P＜0.05). Overexpression of GH can increase the activity of NF-κB about 1.7 times in TaxP cells (P＜0.05). Conclusion GH maybe involve in adult T-cell leukemia(ATL) through activating NF-κB.