Lack of antiretroviral effect of alpha-interferon in HIV-infected patients treated for chronic hepatitis C.
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Adult↗
Biomedical subjects
R Bravo
Publications and source records attributed to R Bravo.
Osteopetrosis in mice lacking NF-kappaB1 and NF-kappaB2.
The nfkb1 and nfkb2 genes encode closely related products regulating immune and inflammatory responses. Their role during development and differentiation remains unclear. The generation of nfkb1 null mice (p50-/-) resulted in altered immune responses, but had no effect on development. Similarly, nfkb2 knockout mice (p52-/-) did not show developmental defects (J.C. et al., manuscript submitted). We have investigated the potential for in vivo compensatory functions of these genes by generating double-knockout mice. The surprising result was that the animals developed osteopetrosis because of a defect in osteoclast differentiation, suggesting redundant functions of NF-kappaB1 and NF-kappaB2 proteins in the development of this cell lineage. The osteopetrotic phenotype was rescued by bone marrow transplantation, indicating that the hematopoietic component was impaired. These results define a new mouse osteopetrotic mutant and implicate NF-kappaB proteins in bone development, raising new directions in the treatment of bone disorders.
Animals↗
Increased brain transcription factor expression by angiotensin in genetic hypertension.
A stimulated brain renin-angiotensin system has been implicated in genetic hypertension. We compared the effects of an intracerebroventricular injection of angiotensin II (100 ng) on the expression of inducible transcription factors c-Fos, c-Jun, and Krox-24 in the brain of spontaneously hypertensive rats (SHR). in Wistar rats with nephrogenic hypertension induced by aortic banding, and in normotensive Wistar-Kyoto and Wistar rats immunohistochemically. Generally, the angiotensin II-induced transcription factor expression was strictly confined to four distinct forebrain areas: the subfornical organ, median preoptic area, paraventricular nucleus, and supraoptic nucleus. In SHR, the angiotensin II-induced c-Fos and c-Jun expressions were significantly enhanced compared with those in normotensive control strains as well as in secondary hypertensive Wistar rats. Krox-24 expression in the subfornical organ, median preoptic area, and paraventricular nucleus of SHR was also significantly increased compared with that in all control strains. In the supraoptic nucleus, significant differences could be discriminated between SHR and secondary hypertensive Wistar rats. Injection of isotonic saline or arginine vasopressin (100 ng) as controls did not induce any expression of c-Fos, c-Jun, or Krox-24. Our findings demonstrate an enhanced sensitivity of SHR to angiotensin II-induced transcription factor expression in distinct brain areas involved in central blood pressure and osmotic control that is independent of blood pressure.
Angiotensin II↗
Comparison of three different commercial methods for quantification of plasma HIV RNA in clinical specimens.
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Branched DNA Signal Amplification Assay↗
Relapses of chronic hepatitis C in HIV-infected patients who responded to interferon therapy. Hepatitis/HIV Spanish Study Group.
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Alanine Transaminase↗
Influence of hepatitis C virus genotypes and HIV infection on histological severity of chronic hepatitis C. The Hepatitis/HIV Spanish Study Group.
OBJECTIVES: The factors influencing the histological severity of chronic hepatitis C (CHC) have not been well established. We therefore investigated the effect of hepatitis C virus (HCV) genotypes and human immunodeficiency virus (HIV) infection on histological liver damage in a cohort of intravenous drug users with CHC. METHODS: We analyzed the histological activity score and the HCV genotypes in 59 HCV-RNA-positive patients with biopsy-proven CHC. Forty-eight (81%) of them had concomitant HIV infection with a CD4+ cell count above 200 x 10(6) cells/L and an absence of AIDS-defining conditions. Multivariate analysis was performed to determine the features associated with the histological severity. RESULTS: Minimal/mild hepatitis was found in 16 patients (27%), moderate chronic hepatitis in 29 (49%), and severe chronic hepatitis in 14 (24%). Patients with HCV subtype 1b had a higher histological score than others (8.7 +/- 3.3 vs. 6.5 +/- 3.2, p = 0.012), either as single or mixed infections. In multivariate analysis, HIV-infected individuals had a higher score of piecemeal necrosis (OR = 21.7, p = 0.002) and a higher stage of fibrosis (OR = 17.9, p = 0.004) than patients without HIV infection. HIV infection and HCV genotype 1b were found to be independent factors of histological severity. CONCLUSIONS: Liver damage in patients with CHC seems to be directly influenced by HCV subtypes. Infection by HCV subtype 1b is closely associated with more severe forms of liver pathology. Furthermore, the presence of HIV infection is an independent factor associated with more aggressive histological damage. In these patients, higher degrees of piecemeal necrosis and fibrosis are commonly seen.
Adult↗
[Frequency and characteristics of patients treated with zidovudine and absence of progression of HIV infection].
BACKGROUND: the efficacy of zidovudine (ZDV) is lost in many treated individuals after a few weeks or months of monotherapy. The development of drug resistance seems to explain this adverse event. However, some individuals seem to persistently benefit clinically and immunologically from ongoing ZDV monotherapy. The degree and causes of this phenomenon remain unclear. PATIENTS AND METHODS: we studied 280 HIV-infected patients who have been receiving ZDV monotherapy for more than 18 months (mean 28 +/- 7 months), and whom has a CD4+ count between 200 and 500 x 10(6)/l at baseline. We classified them into two groups: Non-progressors with ZDV (NP-ZDV), subjects with an increase or a reduction < 15% in the CD4+ count; and Progressors with ZDV (P-ZDV), subjects showing a decline in the CD4 count > 15%. Epidemiological, immunological and virological features of each group were compared. RESULTS: the prevalence of NP-ZDV in this population was 15.7% (44/280). Age, gender, and risk behaviour were not significantly different in NP-ZDV and P-ZDV. Although the CD4/CD8 ratio, as well as the CD45R0/CD45RA ratio into the CD4+ subpopulation, were higher in NP-ZDV than in P-ZDV, the values did not achieve statistical significance. Virological studies were performed on 36 (81.8%) NP-ZDV and 55 (23.3%) P-ZDV. Mean HIV-RNA titer was higher in P-ZDV than in NP-ZDV (8.4 x 10(4) vs. 1.5 x 10(3) copies/ml; p < 0.01). Virus isolation from circulating mononuclear cells was made more frequently in P-ZDV than in NP-ZDV (90.9% vs. 81.5%), although it did not achieve statistical significance. The syncitium-inducing (SI) phenotype was detected in more than a quarter (27.3%) of P-ZDV but was absent in NP-ZDV (p < 0.01). The prevalence of RT mutations at codon 215 was much lower in NP-ZDV than in P-ZDV, and it showed a strong statistical significance (13.9% vs. 74.5%; p < 0.01). CONCLUSIONS: prolonged (> 2 years) lack of immunological and clinical progression can be observed in 15% of HIV-infected persons with mild immunosuppression, undertaking ZDV monotherapy. This effect seems to be associated with a characteristic virological profile, in which a low viral load, the absence of SI phenotype, and a lack of development of ZDV-resistance are the most relevant features.
Adult↗
[Rapid and slow progression of the infection by the type 1 human immunodeficiency virus in a population of seropositive subjects in Madrid].
BACKGROUND: The rate of progression to AIDS in HIV-1 infected subjects is variable, and circumstances associated with more rapid or slow development of severe immunodeficiency might be grouped in three categories; environmental cofactors, host features, and particular virulence of the virus itself. Currently, it is not yet clear the the relative impact of each one. PATIENTS AND METHODS: A cross-sectional study was done in a cohort of 1,783 IV-1 infected persons from three centers located in Madrid, mainly devoted to attend persons at risks for HIV infection. Long-term nonprogressors (LTNP) were defined as those with more than 8 years of confirmed HIV seropositivity, and CD4+ T-cell count above 500 x 10(6)/I in the absence of antiretroviral therapy or symptoms suggesting immunodeficiency. Rapid progressors (RP) were those with less than 5 years from seroconversion and repeatedly current CD4+ T-cell count below 200 x 10(6)/I. An analysis of different epidemiological, immunological and virological features was performed comparing LTNP and RP. RESULTS: Among 1,783 HIV (+) subjects studied, 100 (5.6%) fulfilled criteria for LTNP and 12 (0.7%) for RP. Among LTNP, stabilized CD4 slope was seen in 16 (33%) out of 48 after more than 8 years of infection. Variables statistically associated with LTNP were: past history of intravenous drug addiction (80% of them), male gender (79% of them), high alcohol intake (48% of them), HIV-1 non-syncitium inducing viral phenotype, and very low or undetectable HIV-1 plasma viremia. In contrast, variables associated with RP were: infection by sexual contact (75% of cases), female gender (50% of them), syncitium-inducing viral plenotype, and high titers of plasma viremia. The CD4/CD8 ratio below 1 was seen in all RP and in 88% of LTNP. However, a preferent depletion of CD4+ cell occurred in the first group, instead of an enhancement of the CD8 T-cell count in LTNP. The prevalence of serological markers for hepatotropic viruses and other potential infectious cofactors was not higher in RP. CONCLUSIONS: Multiple factors seems to account for the different rate of disease progression observed in HIV-1 infected persons. The dynamic equilibrium between the immune system and the virulence of the virus seem to be influenced--but not determined--by environmental infectious or non infectious cofactors.
Acquired Immunodeficiency Syndrome↗
Both multiorgan inflammation and myeloid hyperplasia in RelB-deficient mice are T cell dependent.
Mice with a targeted disruption of RelB, a member of the Rel/NF-kappaB family of transcription factors, have multifocal, mixed inflammatory cell infiltration in several organs, myeloid hyperplasia, and splenomegaly due to extramedullary hemopoiesis. To elucidate the cellular requirements for this complex phenotype, we have bred RelB-deficient (RelB(kappaO)) animals to two strains of immunodeficient mice, recombinase-activating gene-1-deficient (RAG-1(kappaO), lacking B and T cells), and Nur77/N10-transgenic mice (Nur77/N10(TG), lacking only T cells). We also generated mutant mice deficient in both RelB and the p50 subunit of NF-kappaB (p50(kappaO), multiple defects in B cell function). RelB(kappaO)RAG-1(kappaO) and RelB(kappaO)Nur77/N10(TG) mice are disease-free, while RelB(kappaO)p50(kappaO) double-mutant animals develop an even more severe phenotype despite the absence of B cells in the inflammatory infiltrates. Thus, both multiorgan inflammation and myeloid hyperplasia in RelB-deficient mice are T cell dependent, whereas B cells are not crucially involved.
Animals↗
[Report of the first 2 cases of HIV-1 group O infection in Spain].
BACKGROUND: The wide genetic variability of HIV-1 isolates has allowed to classify them into several subtypes. Very high divergent strains have been isolated recently from West Africa patients with AIDS, and they have been called HIV-1 group O ("outlier"). PATIENTS AND METHODS: In April 1995 a couple of patients was referred for medical follow-up and definitive diagnosis of HIV-1 infection. Both were white and had been born in Spain. The husband had been working for 10 years in West Africa. CD4+ T-cell counts were below 250 x 10(6)/l in both subjects, and the wife had developed seborrheic dermatitis and mild pancytopenia. Serologic and genetic studies were performed to study the presence of HIV-1 group O infection in this couple. RESULTS: Serological tests (enzyme immunoassays, Western blot, line immunoassay) yielded indeterminate results for HIV-1 testing serum from the wife, but the husband's specimen was positive. Serological test for HIV-2 were negative in both subjects. In contrast, a new test allowed recognition of specific antibodies to HIV-1 group O in these patients. Furthermore, this infection was confirmed using a discriminative PCR methodology, which demonstrated the presence of specific HIV-1 group O sequences and the absence of group M sequences. CONCLUSIONS: The first two cases of HIV-1 group O infection in Spain are described. It is pointed that diagnostic tests and therapeutic strategies need to considers the presence of this new HIV variant outside endemic areas.
Adult↗
B cells lacking RelB are defective in proliferative responses, but undergo normal B cell maturation to Ig secretion and Ig class switching.
A number of distinct functional abnormalities have been observed in B cells derived from p50/ NF-kappa B or c-rel knockout mice. RelB, another member of the NF-kappa B/Rel family of transcription factors, is expressed during the latter stages of B cell maturation and can bind to regulatory sites within the Ig heavy chain locus. Therefore, we tested the ability of B cells from relB knockout mice (relB-/-) to proliferate, undergo maturation to IgM secretion, and switch to the expression of downstream Ig isotypes in response to distinct activators including LPS, anti-CD40 mAb or CD40 ligand, and/or dextran anti-IgD antibodies in combination with various cytokines, including IL-4, IL-5, IFN-gamma, and TGF-beta. B cells lacking RelB showed up to 4-fold reductions in DNA synthesis in response to LPS, CD40, and membrane Ig-dependent activation relative to controls. However, relB-/- B cells were comparable to control B cells in their ability to undergo maturation to IgM secretion and switch to the expression of IgG3, IgG1, IgG2b, IgG2a, IgE, and/or IgA under all activation conditions tested. Thus, RelB, like c-Rel and p50/NF-kappa B, plays a role in B cell proliferation. However, in contrast to c-Rel and p50/ NF-kappa B, it is not critically involved in maturation to Ig secretion or expression of Ig isotypes.
Animals↗
Transient expression of the mitogen-activated protein kinase phosphatase MKP-1 (3CH134/ERP1) in the rat brain after limbic epilepsy.
The immediate early gene-encoded enzyme, MAP kinase phosphatase 1 (MKP-1), is thought to be a key element in controlling cellular signalling pathways activated by MAP kinases. Since MAP kinase have been demonstrated to participate in neuronal stimulus-transcription coupling following seizure activity, the present study investigated the induction of MKP-1 in the rat brain after limbic epilepsy. MKP-1 expression was studied with a polyclonal antiserum by Western blots, immunocytochemistry and immuno-electron microscopy at different time periods between 1 and 24 h after kainic acid-induced limbic seizures. MKP-1 induction was identified in dentate granule cells of the hippocampus but not in pyramidal neurons, furthermore in neurons of the outer layers of the neocortex, as well as in neurons of the lateral nucleus of the bed of the stria terminalis. Immuno-electron microscopy demonstrated that MKP-1 was localized in the neuronal nucleus, where the substrate of MKP-1, activated MAP kinases, are also found. In view of the restricted areas of MKP-1 expression and the widespread areas of altered MAP kinases activity it can be concluded that in the majority of CNS populations other mechanisms than MKP-1 induction are responsible for the shut-off of MAP kinases following seizure activity. MKP-1 may contribute in the specific subpopulations where it is induced to the post-translational control of inducible transcription factors of the fos, jun and myc family.
Animals↗
Disruption of the erp/mkp-1 gene does not affect mouse development: normal MAP kinase activity in ERP/MKP-1-deficient fibroblasts.
Externally regulated phosphatase (ERP or MKP-1) is a dual specificity phosphatase that has been implicated in the dephosphorylation of mitogen activated protein kinases (MAP kinases). MAP kinase is activated in response to external signals and in turn phosphorylates proteins essential to the regulation of cell growth. To study the role of ERP/MKP-1 protein in mammalian development and its function in signal transduction we have generated mice, embryonic stem (ES), cells and mouse embryo fibroblasts (MEFs) that are deficient in the ERP/MKP-1 protein. ERP/MKP-1-deficient mice are born at normal frequency, are fertile and present no phenotypic or histologic abnormalities. MAP kinase activity and the induction of c-fos mRNA is unaltered in MEFs lacking the ERP/MKP-1 protein, indicating no alteration of the MAP kinase pathway. In addition, ERP/MKP-1 deficient MEFs grow and enter DNA synthesis at the same rate as control cells. Our results demonstrate that the activity of ERP/MKP-1 is not essential for embryo development and indicate that the lack of ERP/MKP-1 activity can be compensated by other phosphatases in vivo.
Animals↗
Characterization of ES cells deficient for the p105 precursor (NF-kappa B1): role of p50 NLS.
Proteolytic processing of the p105 precursor (NF-kappa B1) generates the p50 subunit of NF-kappa B. To address the function of p105 precursor, we have generated embryonic stem (ES) cells which lack the C-terminal inhibiting ankyrin-containing domain of p105 (I kappa B gamma) but contain a functional p50 by homologous recombination. Two forms of p50 were found in ES cells lacking p105. While one was a p50 molecule with the expected size of 415 amino acids, the other was an isoform of 358 amino acids generated by alternative splicing. This isoform lacked the C-terminal 62 amino acids of p50 including the putative nuclear localization signal (NLS), but included five unrelated amino acids. This p50 molecule lacking the NLS behaved similar to wild type p50. Importantly, the p50 isoform-RelA complex interacted efficiently with I kappa B alpha, implying that the NLS of p50 is not essential for these functions. Also, p50 isoform dimers were present in the nucleus. Loss of p105 and the augment of total p50 produced an increase in the nuclear kappa B-binding activity of p50-RelA and p50 dimers. In wild type ES cells, a significant proportion of total p50 is associated with p105. Therefore, the mutation introduced in NF-kappa B1 eliminates both the processing to generate p50 and the trapping of p50 by p105. In contrast to p50, only a small fraction of RelA is associated with p105. These findings indicate that p105 plays a unique role in controlling p50 dimer activity.
Alternative Splicing↗
Neutrophil infiltration, glial reaction, and neurological disease in transgenic mice expressing the chemokine N51/KC in oligodendrocytes.
Chemokines (pro-inflammatory chemoattractant cytokines) are expressed in pathological conditions of the central nervous system (CNS). Previous studies suggested that the CNS is relatively resistant to leukocyte diapedesis after chemokine injection, leaving their functional role unresolved. The CNS function of N51/KC, a neutrophil-selective chemokine, was addressed by expressing N51/KC under control of the myelin basic protein (MBP) promoter in transgenic (tg) mice (MBP-N51/KC mice). CNS-specific N51/KC expression produced remarkable neutrophil infiltration into perivascular, meningeal, and parenchymal sites, demonstrating that this chemokine exerts the multiple functions in vivo required to recruit leukocytes into the CNS. MBP-N5 1/KC mice represent an incisive model for the molecular dissection of neutrophil entry into the CNS. Unexpectedly, MBP-N51/KC mice developed a neurological syndrome of pronounced postural instability and rigidity at high frequency beginning at 40 days of age, well after peak chemokine expression. 68/182 mice in one tg fine were found dead before one year of age, with prominent neurological symptoms premortem in 26 (38%). Florid microglial activation and blood-brain barrier disruption without dysmyelination were the major neuropathological alterations. Late-onset neurological symptoms in MBP-N51/KC mice may indicate unanticipated consequences of CNS chemokine expression.
Animals↗
The v-rel oncogene promotes malignant T-cell leukemia/lymphoma in transgenic mice.
The oncogene product from the avian reticuloendotheliosis virus strain T, v-Rel, is a member of the Rel/ NF-kappa B family of transcription factors. The mechanism by which v-Rel induces oncogenic transformation remains unclear. Several attempts to transform mammalian cells with v-Rel have failed, suggesting that v-Rel transformation may be a species-specific event. However, here we demonstrate that v-Rel, but not a truncated c-Rel, expressed under the control of the lck promoter, efficiently induced malignancies in transgenic mice. Most of the animals died before 10 months of age and developed immature, multicentric aggressive T-cell leukemia/lymphomas. Most tumors contain CD4+CD8+ cells or CD4-CD8+ cells, which have an immature rather than a mature peripheral phenotype. No tumor development was observed in control littermates and transgenic mice expressing a truncated form of c-Rel. Tumor formation was correlated with the presence of constitutive p50/v-Rel DNA binding activity and overexpression of several kappa B-regulated genes in v-rel transgenic thymocytes. However, v-Rel is also transforming in transgenic thymocytes lacking p50, indicating that p50/v-Rel heterodimer formation is not essential for the transforming activity of v-Rel. The transforming activity of v-Rel in p50 null mice has been identified as v-Rel/v-Rel homodimers. Since tumors represent immature T-lymphocytes, constitutive v-Rel expression appears to be leukemogenic at earlier stages of T-cell development. These v-Rel mice should aid in the study of lymphoma development, T-cell development and NF-kappa B regulation.
Animals↗
Apoptosis of nur77/N10-transgenic thymocytes involves the Fas/Fas ligand pathway.
The orphan nuclear receptor Nur77/N10 has recently been demonstrated to be involved in apoptosis of T cell hybridomas. We report here that chronic expression of Nur77/N10 in thymocytes of transgenic mice results in a dramatic reduction of CD4+CD8+ double-positive as well as CD4+CD8- and CD4-CD8+ single-positive cell populations due to an early onset of apoptosis. CD4-CD8- double-negative and CD25+ precursor cells, however, are unaffected. Moreover, nur77/N10-transgenic thymocytes show increased expression of Fas ligand (FasL), while the levels of the Fas receptor (Fas) are not increased. The mouse spontaneous mutant gld (generalized lymphoproliferative disease) carries a point mutation in the extracellular domain of the FasL gene that abolishes the ability of FasL to bind to Fas. Thymuses from nur77/N10-transgenic mice on a gld/gld background have increased cellularity and an almost normal profile of thymocyte subpopulations. Our results demonstrate that one pathway of apoptosis triggered by Nur77/N10 in double-positive thymocytes occurs through the upregulation of FasL expression resulting in increased signaling through Fas.
Animals↗
Cloning and functional expression of mCCR2, a murine receptor for the C-C chemokines JE and FIC.
The C-C chemokines human monocyte chemoattractant protein-1 and -3 (MCP-1 and MCP-3) and mouse JE and FIC are potent activators of monocytes. Several receptors for MCP-1 and MCP-3 have been cloned from human monocytic cell lines, and one of these receptors, CCR2B, binds both MCP-l and MCP-3. Thus far, no murine receptors for JE or FIC have been reported. We have cloned a novel murine C-C chemokine receptor, designated mouse CCR2 (mCCR2), from the mouse monocyte cell line WEHI265.1. The predicted 373-amino acid sequence of mCCR2 shows highest identity (80%) with CCR2B. When stably expressed in human embryonic kidney 293 cells, mCCR2 specifically bound 125I-JE with high affinity. FIC was less potent than JE in competing 125I-JE binding to mCCR2-expressing cells, while three other mouse chemokines, MIP-1alpha, C10, and N51/KC, did not compete. mccr2 mRNA expression was detected in elicited peritoneal macrophages as well as in several mouse organs. The cloning of mCCR2 provides an important tool to investigate monocyte/macrophage responses to JE and FIC, to identify other targets for their action, and potentially to study models of CCR2 function in the mouse.
Amino Acid Sequence↗