RESUMEN

Although previous studies have shown that CD4+ T cells expressing CCR6 and CD161 are depleted from blood during HIV infection, the mechanisms underlying their loss remain unclear. In this study, we investigated how the homeostasis of CCR6+ and CD161+ CD4+ T cells contributes to SIV disease progression and the mechanisms responsible for their loss from circulation. By comparing SIV infection in rhesus macaques (RMs) and natural host sooty mangabeys (SMs), we found that the loss of CCR6+ and CD161+ CD4+ T cells from circulation is a distinguishing feature of progressive SIV infection in RMs. Furthermore, while viral infection critically contributes to the loss of CD161+CCR6-CD4+ T cells, a redistribution of CCR6+CD161- and CCR6+CD161+CD4+ T cells from the blood to the rectal mucosa is a chief mechanism for their loss during SIV infection. Finally, we provide evidence that the accumulation of CCR6+CD4+ T cells in the mucosa is damaging to the host by demonstrating their reduction from this site following initiation of antiretroviral therapy in SIV-infected RMs and their lack of accumulation in SIV-infected SMs. These data emphasize the importance of maintaining CCR6+ and CD161+ CD4+ T-cell homeostasis, particularly in the mucosa, to prevent disease progression during pathogenic HIV/SIV infection.

Asunto(s)

Linfocitos T CD4-Positivos/inmunología , Infecciones por VIH/inmunología , VIH-1/inmunología , Mucosa Intestinal/inmunología , Recto/patología , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Virus de la Inmunodeficiencia de los Simios/inmunología , Animales , Movimiento Celular , Cercocebus atys , Progresión de la Enfermedad , Reservorios de Enfermedades/virología , Femenino , Homeostasis , Humanos , Mucosa Intestinal/virología , Macaca mulatta , Subfamilia B de Receptores Similares a Lectina de Células NK/metabolismo , Receptores CCR6/metabolismo

RESUMEN

Human immunodeficiency virus (HIV) and Simian immunodeficiency virus (SIV) disease progression is associated with multifocal damage to the gastrointestinal tract epithelial barrier that correlates with microbial translocation and persistent pathological immune activation, but the underlying mechanisms remain unclear. Investigating alterations in mucosal immunity during SIV infection, we found that damage to the colonic epithelial barrier was associated with loss of multiple lineages of interleukin (IL)-17-producing lymphocytes, cells that microarray analysis showed expressed genes important for enterocyte homeostasis, including IL-22. IL-22-producing lymphocytes were also lost after SIV infection. Potentially explaining coordinate loss of these distinct populations, we also observed loss of CD103+ dendritic cells (DCs) after SIV infection, which associated with the loss of IL-17- and IL-22-producing lymphocytes. CD103+ DCs expressed genes associated with promotion of IL-17/IL-22+ cells, and coculture of CD103+ DCs and naïve T cells led to increased IL17A and RORc expression in differentiating T cells. These results reveal complex interactions between mucosal immune cell subsets providing potential mechanistic insights into mechanisms of mucosal immune dysregulation during HIV/SIV infection, and offer hints for development of novel therapeutic strategies to address this aspect of AIDS virus pathogenesis.

Asunto(s)

Colon/inmunología , Células Dendríticas/inmunología , Enterocitos/inmunología , Inmunidad Mucosa , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Virus de la Inmunodeficiencia de los Simios/fisiología , Células Th17/inmunología , Animales , Antígenos CD/inmunología , Diferenciación Celular , Linaje de la Célula , Técnicas de Cocultivo , Colon/patología , Colon/virología , Células Dendríticas/patología , Células Dendríticas/virología , Enterocitos/patología , Enterocitos/virología , Regulación de la Expresión Génica , Cadenas alfa de Integrinas/deficiencia , Cadenas alfa de Integrinas/inmunología , Interleucina-17/deficiencia , Interleucina-17/genética , Interleucina-17/inmunología , Interleucinas/deficiencia , Interleucinas/genética , Interleucinas/inmunología , Macaca mulatta , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/patología , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Células Th17/patología , Células Th17/virología , Interleucina-22

RESUMEN

A major limitation of highly active antiretroviral therapy is that it fails to eradicate human immunodeficiency virus (HIV) infection due to its limited effects on viral reservoirs carrying replication-competent HIV, including monocytes/macrophages (M/M). Therefore, therapeutic approaches aimed at targeting HIV-infected M/M may prove useful in the clinical management of HIV-infected patients. In previous studies, we have shown that administration of fludarabine-loaded red blood cells (RBC) in vitro selectively induces cell death in HIV-infected M/M via a pSTAT1-dependent pathway. To determine the in vivo efficacy of this novel therapeutic strategy, we treated six naturally simian immunodeficiency virus (SIV)-infected sooty mangabeys (SMs) with either 9-[2-(R)-(phosphonomethoxy)propyl]adenine (PMPA) only, fludarabine-loaded RBC only, or PMPA in association with fludarabine-loaded RBC. The rationale of this treatment was to target infected M/M with fludarabine-loaded RBC at a time when PMPA is suppressing viral replication taking place in activated CD4+ T cells. In vivo administration of fludarabine-loaded RBC was well tolerated and did not induce any discernible side effect. Importantly, addition of fludarabine-loaded RBC to PMPA delayed the rebound of viral replication after suspension of therapy, thus suggesting a reduction in the size of SIV reservoirs. While administrations of fludarabine-loaded RBC did not induce any change in the CD4+ or CD8+ T-cell compartments, we observed, in chronically SIV-infected SMs, a selective depletion of M/M expressing pSTAT1. This study suggests that therapeutic strategies based on the administration of fludarabine-loaded RBC may be further explored as interventions aimed at reducing the size of the M/M reservoirs during chronic HIV infection.

Asunto(s)

Macrófagos/efectos de los fármacos , Macrófagos/virología , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Vidarabina/análogos & derivados , Adenina/administración & dosificación , Adenina/análogos & derivados , Animales , Terapia Antirretroviral Altamente Activa , Antivirales/administración & dosificación , Cercocebus atys , Portadores de Fármacos , Eritrocitos/metabolismo , Femenino , Humanos , Macrófagos/metabolismo , Masculino , Agonistas Mieloablativos/administración & dosificación , Organofosfonatos/administración & dosificación , Factor de Transcripción STAT1/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio/sangre , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Subgrupos de Linfocitos T/efectos de los fármacos , Tenofovir , Vidarabina/administración & dosificación , Viremia/tratamiento farmacológico , Viremia/prevención & control , Viremia/virología , Replicación Viral/efectos de los fármacos

RESUMEN

In contrast to human immunodeficiency virus (HIV) infection of humans and experimental simian immunodeficiency virus (SIV) infection of rhesus macaques (RMs), SIV infection of sooty mangabeys (SMs), a natural host African monkey species, is typically nonpathogenic and associated with preservation of CD4+ T-cell counts despite chronic high levels of viral replication. In previous studies, we have shown that the lack of SIV disease progression in SMs is related to lower levels of immune activation and bystander T-cell apoptosis compared to those of pathogenic HIV/SIV infection (G. Silvestri, D. Sodora, R. Koup, M. Paiardini, S. O'Neil, H. M. McClure, S. I. Staprans, and M. B. Feinberg, Immunity 18:441-452, 2003; G. Silvestri, A. Fedanov, S. Germon, N. Kozyr, W. J. Kaiser, D. A. Garber, H. M. McClure, M. B. Feinberg, and S. I. Staprans, J. Virol. 79:4043-4054, 2005). In HIV-infected patients, increased T-cell susceptibility to apoptosis is associated with a complex cell cycle dysregulation (CCD) that involves increased activation of the cyclin B/p34-cdc2 complex and abnormal nucleolar structure with dysregulation of nucleolin turnover. Here we report that CCD is also present during pathogenic SIV infection of RMs, and its extent correlates with the level of immune activation and T-cell apoptosis. In marked contrast, naturally SIV-infected SMs show normal regulation of cell cycle control (i.e., normal intracellular levels of cyclin B and preserved nucleolin turnover) and a low propensity to apoptosis in both peripheral blood- and lymph node-derived T cells. The absence of significant CCD in the AIDS-free, non-immune-activated SMs despite high levels of viral replication indicates that CCD is a marker of disease progression during lentiviral infection and supports the hypothesis that the preservation of cell cycle control may help to confer the disease-resistant phenotype of SIV-infected SMs.

Asunto(s)

Ciclo Celular/fisiología , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Virus de la Inmunodeficiencia de los Simios/inmunología , Subgrupos de Linfocitos T/fisiología , Animales , Apoptosis , Biomarcadores , Proteína Quinasa CDC2/metabolismo , Cercocebus atys , Ciclina B/metabolismo , Leucocitos Mononucleares , Ganglios Linfáticos/inmunología , Activación de Linfocitos , Macaca mulatta , Fosfoproteínas/metabolismo , Proteínas de Unión al ARN/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/patogenicidad , Especificidad de la Especie , Subgrupos de Linfocitos T/metabolismo , Carga Viral , Nucleolina

Asunto(s)

Eritrocitos , Macrófagos/efectos de los fármacos , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Virus de la Inmunodeficiencia de los Simios/crecimiento & desarrollo , Vidarabina/análogos & derivados , Animales , Cercocebus atys , Diálisis , Esquema de Medicación , Sistemas de Liberación de Medicamentos/métodos , Macrófagos/inmunología , Fosforilación , Síndrome de Inmunodeficiencia Adquirida del Simio/sangre , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Vidarabina/administración & dosificación , Vidarabina/sangre , Vidarabina/química , Vidarabina/toxicidad , Carga Viral

RESUMEN

For a number of years the pathogenesis of AIDS was thought to be essentially related to direct human immunodeficiency virus (HIV)-mediated killing of CD4+ T cells. More recently, attention has shifted to pathogenic models that emphasize the role of generalized immune system activation and the excess apoptosis of uninfected T cells in inducing HIV-associated CD4+ T-cell depletion. The main focus of our research is to better define the determinants and the consequences of these "indirect" mechanisms of immunodeficiency by studying both HIV-infected patients and nonhuman primates infected with simian immunodeficiency virus (SIV). We have discovered that pathogenic models of retroviral infections of primates (i.e., HIV infection in humans and SIV infection in rhesus macaques) are associated with the presence of a set of perturbations of normal cell-cycle control in T lymphocytes. These perturbations, to which we collectively refer to as cell-cycle dysregulation, or CCD, may represent an important biological link between chronic immune activation and excess apoptosis and therefore may play a significant role in the pathogenesis of AIDS. A better understanding of the determinants and consequences of CCD may pave the way for the introduction of new therapeutic strategies to be used in addition to standard antiretroviral therapy in HIV-infected patients.

Asunto(s)

Síndrome de Inmunodeficiencia Adquirida/inmunología , Linfocitos T CD4-Positivos/inmunología , Animales , Apoptosis/inmunología , Linfocitos T CD4-Positivos/citología , Ciclo Celular/inmunología , Ciclo Celular/fisiología , Supresión Clonal/inmunología , Ciclina B/metabolismo , VIH/inmunología , VIH/patogenicidad , Humanos , Interleucina-2/inmunología , Fosfoproteínas/metabolismo , Proteínas de Unión al ARN/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Virus de la Inmunodeficiencia de los Simios/inmunología , Virus de la Inmunodeficiencia de los Simios/patogenicidad , Nucleolina

RESUMEN

Overexpression of cyclin D1, the regulatory subunit of cyclin-dependent kinases (cdk4 and cdk6) involved in cell cycle control, has often been found in breast cancer and other types of human cancer. Increased expression, or stability, of cyclin D1 molecules may cause sufficient cdk4 activation to produce retinoblastoma protein phosphorylation independently of mitogenic signals; this results in commitment of cells to the G1 phase at mitosis. In the present study, cyclin D1 expression was investigated in pre-cancerous and cancerous lesions of the canine mammary gland by a complex experimental approach, which included Western blot and immunohistochemical analysis of cyclin D1 and the related molecular system. Furthermore, to define relationships between cell growth and expression of cyclin D1, proliferative activity was studied by the AgNOR technique. The study provided the following information. Cyclin D1 overexpression was largely independent of the type of proliferative anomaly. Indeed, cyclin D1 was expressed in 60% of the pre-cancerous lesions and in 44% of cancerous lesions. Mitotic activity and cyclin D1 expression were related: mammary lesions that expressed cyclin D1 showed a high proliferative ratio, the opposite being true of cyclin D1-negative cell populations. This study may contribute to the establishment of an animal model for anti-cancer research based on cyclin D1 suppression or cdk inactivation, or both.

Asunto(s)

Adenocarcinoma/veterinaria , Carcinoma in Situ/veterinaria , Ciclina D1/metabolismo , Enfermedades de los Perros/metabolismo , Glándulas Mamarias Animales/metabolismo , Neoplasias Mamarias Animales/metabolismo , Lesiones Precancerosas/veterinaria , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Animales , Western Blotting/veterinaria , Carcinoma in Situ/metabolismo , Carcinoma in Situ/patología , Enfermedades de los Perros/patología , Perros , Femenino , Técnicas para Inmunoenzimas/veterinaria , Glándulas Mamarias Animales/patología , Neoplasias Mamarias Animales/patología , Región Organizadora del Nucléolo , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/patología , Tinción con Nitrato de Plata/veterinaria

RESUMEN

Human immunodeficiency virus (HIV)-induced immunodeficiency is characterized by progressive loss of CD4(+) T cells associated with functional abnormalities of the surviving lymphocytes. Increased susceptibility to apoptosis and loss of proper cell cycle control can be observed in lymphocytes from HIV-infected individuals and may contribute to the lymphocyte dysfunction of AIDS patients. To better understand the relation between T-cell activation, apoptosis, and cell cycle perturbation, we studied the effect of exogenous interleukin-2 (IL-2) administration on the intracellular turnover of phase-dependent proteins. Circulating T cells from HIV-infected patients display a marked discrepancy between a metabolic profile typical of G(0) and a pattern of expression of phase-dependent proteins that indicates a more-advanced position within the cell cycle. This discrepancy is enhanced by in vitro activation with ConA and ultimately results in a marked increase of apoptotic events. Conversely, treatment of lymphocytes with IL-2 alone restores the phase-specific pattern of expression of cell cycle-dependent proteins and is associated with low levels of apoptosis. Interestingly, exogenous IL-2 administration normalizes the overall intracellular protein turnover, as measured by protein synthesis, half-life of newly synthesised proteins, and total protein ubiquitination, thus providing a possible explanation for the effect of IL-2 on the intracellular kinetics of cell cycle-dependent proteins. The beneficial effect of IL-2 administration is consistent with the possibility of defective IL-2 function in vivo, which is confirmed by the observation that lymphocytes from HIV-infected patients show abnormal endogenous IL-2 paracrine/autocrine function upon in vitro mitogen stimulation. Overall these results confirm that perturbation of cell cycle control contributes to HIV-related lymphocyte dysfunction and, by showing that IL-2 administration can revert this perturbation, suggest a new mechanism of action of IL-2 therapy in HIV-infected patients.

Asunto(s)

Ciclo Celular/efectos de los fármacos , Infecciones por VIH/inmunología , Interleucina-2/farmacología , Linfocitos/efectos de los fármacos , Terapia Antirretroviral Altamente Activa , Nucléolo Celular , Cisteína Endopeptidasas/biosíntesis , Infecciones por VIH/tratamiento farmacológico , Humanos , Interleucina-2/biosíntesis , Linfocitos/fisiología , Complejos Multienzimáticos/biosíntesis , Ornitina Descarboxilasa/biosíntesis , Complejo de la Endopetidasa Proteasomal

RESUMEN

Human immunodeficiency virus (HIV)-infection is characterized by loss of CD4+ T cells associated with high levels of immune activation, T-cell proliferation, and lymphocyte apoptosis. To investigate the role of intrinsic perturbations of cell-cycle control in the immunopathogenesis of acquired immunodeficiency syndrome (AIDS), we studied the expression of cell-cycle-dependent proteins in lymphocytes from HIV-infected patients. Cyclin B1 expression, Nucleolar Organizer Regions (NORs) number, and NORs area of distribution were all consistently increased in HIV-infected patients, but returned to normal after effective antiretroviral therapy, suggesting that viral replication is directly implicated in the genesis of the observed changes. Analysis of cyclin B1 intracellular turnover showed that the increased cyclin B1 expression is (1) caused by defective degradation in the presence of normal rates of synthesis, and (2) is temporally associated with decreased levels of ubiquitination. After in vitro activation of lymphocytes from healthy individuals, cyclin B1 and cdc25 expression and ubiquitination, p34 cdc2 activity, NORs morphology, and C23/nucleolin localization showed a 72- to 96-hour cyclic pattern that led to a biologic state similar to baseline. On the contrary, complex but consistent changes of the same indices followed activation of T lymphocytes from HIV-infected patients, resulting in a 5-fold increase in apoptosis. Overall, our data indicate that a profound dysregulation of cell-cycle control is present in lymphocytes from HIV-infected patients. This finding may provide a novel biologic link between immune activation, accelerated lymphocyte turnover, and increased apoptosis during HIV infection.

Asunto(s)

Proteínas de Ciclo Celular/metabolismo , Infecciones por VIH/patología , Linfocitos/patología , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , Apoptosis , Proteína Quinasa CDC28 de Saccharomyces cerevisiae/metabolismo , Ciclo Celular , Ciclina B/efectos de los fármacos , Ciclina B/metabolismo , Ciclina B1 , Infecciones por VIH/tratamiento farmacológico , Humanos , Cinética , Región Organizadora del Nucléolo/efectos de los fármacos , Fosfoproteínas/metabolismo , Fosfatasas cdc25/metabolismo

RESUMEN

In this study, the authors describe a new possible animal model to test new anticancer therapies. The selected animals are domestic animals such as dogs, which develop spontaneous tumours very similar in morphology and biology to human ones, also in relation to similar environmental oncogenic pressures. Cycline D1 overexpression, which has both a prognostic and pathogenetic value, is usually detected in human tumours. Thus, the use of cycline-dependent kinases inhibitors could be of value in anticancer therapy. We studied spontaneous canine mammary tumours in order to test the above hypothesis. Immunohistochemistry, AgNOR and western blotting analysis were performed, and the results revealed that cycline D1 is associated with metabolic, morphological and protein expression patterns typical of proliferating cells. The same protein expression pattern, the use of human antibodies for detecting canine proteins and the availability of neoplastic tissue make these spontaneous canine tumours a reliable model.

Asunto(s)

Modelos Animales de Enfermedad , Neoplasias Mamarias Experimentales/terapia , Animales , Perros , Femenino , Neoplasias Mamarias Experimentales/genética , Neoplasias Mamarias Experimentales/patología