RESUMEN
Diffraction is the process by which a beam of light is spread out as a result of passing through a narrow aperture or across an edge. Light diffraction can be produced by closing the aperture diaphragm beyond the recommended setting, by flipping the condenser cone down, or by using an opaque object such as the microscopist's hand to block the column of light and force it to bend around the edge. Any of these techniques results in greater refractility of objects in the path of the light. We studied 77 biopsy specimens from a variety of conditions selected to compare the value of diffractive microscopy, and found that it worked best in the evaluation of alopecia, tumor stroma, hemosiderin, argyria and imipramine pigmentation. In amyloidosis stained with Congo red and silica granuloma, polarized microscopy was superior to diffraction microscopy, and neither diffractive microscopy nor polarized microscopy was superior to routine light microscopy in the evaluation of melanin, chrysiasis or ochronosis.
Asunto(s)
Dermatología/métodos , Microscopía Electrónica de Transmisión/instrumentación , Microscopía Electrónica de Transmisión/métodos , Enfermedades de la Piel/patología , Alopecia/patología , Amiloidosis/patología , Argiria/patología , Humanos , Luz , Microscopía de Polarización/métodos , Dióxido de SilicioRESUMEN
Consumption of the epidermis associated with effacement of the rete ridge pattern has been cited as a useful criterion in the diagnosis of melanoma, but the significance of consumption in the absence of rete ridge effacement is unknown. We evaluated 701 melanocytic neoplasms for presence and 'grade' of consumption by melanocytic nests relative to diagnosis, body location, gender and age. We defined 1+ consumption as collections of melanocytes occupying greater than two thirds of the viable epidermis, with or without loss of the rete ridge pattern. Nests extending to the bottom of, within, and through the granular layer were graded 2+, 3+ and 4+, respectively. Consumption was more frequent and higher grades were found in melanomas followed by Spitz nevi compared with conventional melanocytic nevi (p < 0.001). Melanomas with higher Breslow thickness showed higher grades (p < 0.05). In conventional nevi, consumption occurred most frequently in back (13.7%), acral (11.9%) and scalp (9.8%) locations. Consumption without the requirement for rete ridge effacement occurs more frequently and at higher grades in melanoma. Higher grades correlate with higher Breslow thickness. Consumption is also common in Spitz nevi and occurs at lower grades in conventional (non-Spitz) nevi, especially on the back, the scalp and at acral sites.
RESUMEN
The epidermis of the skin is a multilayered stratified epithelium whose primary function is to provide a barrier against our external environment. As a result, cells in the epidermis are subject to constant assault from environmental pathogens, many of which can cause deleterious mutations. However, most of these mutations do not lead to skin cancer. One explanation is that most genetic hits are sustained by mature or transit cells with limited proliferative capacity and only stem cells that acquire genetic alterations have the potential to propagate a frank tumor. In this mini-review we will discuss recent studies that provide some of the first genetic evidence to support a stem cell origin for a number of skin cancer types.
Asunto(s)
Evolución Clonal , Células Madre Neoplásicas/patología , Neoplasias Cutáneas/patología , Nicho de Células Madre , Transformación Celular Neoplásica/genética , Epidermis/metabolismo , Epidermis/patología , Humanos , Mutación , Células Madre Neoplásicas/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Neoplasias Cutáneas/genética , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Like all primary cells in vitro, normal human melanocytes exhibit a physiologic decay in proliferative potential as it transitions to a growth-arrested state. The underlying transcriptional program(s) that regulate this phenotypic change is largely unknown. To identify molecular determinants of this process, we performed a Bayesian-based dynamic gene expression analysis on primary melanocytes undergoing proliferative arrest. This analysis revealed several related clusters whose expression behavior correlated with the melanocyte growth kinetics; we designated these clusters the melanocyte growth arrest program (MGAP). These MGAP genes were preferentially represented in benign melanocytic nevi over melanomas and selectively mapped to the hepatocyte fibrosis pathway. This transcriptional relationship between melanocyte growth stasis, nevus biology, and fibrogenic signaling was further validated in vivo by the demonstration of strong pericellular collagen deposition within benign nevi but not melanomas. Taken together, our study provides a novel view of fibroplasia in both melanocyte biology and nevogenesis.
Asunto(s)
Transformación Celular Neoplásica/genética , Melanocitos/fisiología , Melanoma/genética , Nevo/genética , Teorema de Bayes , Procesos de Crecimiento Celular/genética , Transformación Celular Neoplásica/patología , Análisis por Conglomerados , Perfilación de la Expresión Génica/métodos , Humanos , Melanocitos/citología , Melanoma/patología , Nevo/patologíaRESUMEN
Lenalidomide, a derivative of thalidomide, is an immunomodulatory agent introduced in 2004 for the treatment of multiple myeloma in combination with dexamethasone. It is also indicated for the treatment of myelodysplastic syndrome and is currently under investigative use for metastatic melanoma. We present a case of neutrophilic dermatosis involving predominantly the lower extremities in a patient receiving lenalidomide therapy for multiple myeloma.
Asunto(s)
Antineoplásicos/efectos adversos , Mieloma Múltiple/tratamiento farmacológico , Síndrome de Sweet/inducido químicamente , Talidomida/análogos & derivados , Biopsia , Femenino , Humanos , Lenalidomida , Persona de Mediana Edad , Piel/patología , Síndrome de Sweet/patología , Talidomida/efectos adversosRESUMEN
The HIV-1 Vpr protein is a viral accessory protein that plays a number of important roles during HIV infection. The activities of Vpr are numerous and include the induction of apoptosis, the modulation of cell cycle arrest, as well as control of viral transcription. Study of HIV clones lacking Vpr in vitro and analysis of HIV variants isolated from long-term nonprogressors in vivo highlight the importance of Vpr for viral replication as well as immune suppression and cell death. Vpr may therefore be considered among the most important accessory proteins encoded by HIV.
Asunto(s)
VIH-1/fisiología , Replicación Viral , Productos del Gen vpr del Virus de la Inmunodeficiencia Humana/fisiología , VIH-1/inmunología , Humanos , Tolerancia InmunológicaRESUMEN
Peptides that are capable of traversing the cell membrane, via protein transduction domains (PTDs), are attractive either directly as drugs or indirectly as carriers for the delivery of therapeutic molecules. For example, an HIV-1 Tat derived peptide has successfully delivered a large variety of "cargoes" including proteins, peptides and nucleic acids into cells when conjugate to the PTD. There also exists other naturally occurring membrane permeable peptides which have potential as PTDs. Specifically, one of the accessory proteins of HIV (viral protein R; i.e., Vpr), which is important in controlling viral pathogenesis, possesses cell transduction domain characteristics. Related to these characteristics, Vpr has also been demonstrated to induce cell cycle arrest and host/target cell apoptosis, suggesting a potential anti-cancer activity for this protein. In this report we assessed the ability of Vpr protein or peptides, with or without conjugation to a PTD, to mediate anti-cancer activity against several tumor cell lines. Specifically, several Vpr peptides spanning carboxy amino acids 65-83 induced significant (i.e., greater than 50%) in vitro growth inhibition/toxicity of murine B16.F10 melanoma cells. Likewise, in in vitro experiments with other tumor cell lines, conjugation of Vpr to the Tat derived PTD and transfection of this construct into cells enhanced the induction of in vitro apoptosis by this protein when compared to the effects of transfection of cells with unconjugated Vpr. These results underscore the potential for Vpr based reagents as well as PTDs to enhance anti-tumor activity, and warrants further examination of Vpr protein and derived peptides as potential therapeutic agents against progressive cell proliferative diseases such as cancer.
Asunto(s)
Antineoplásicos/farmacología , Productos del Gen vpr/metabolismo , VIH-1/fisiología , Péptidos/farmacología , Proteínas/farmacología , Animales , Antineoplásicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Carcinoma/tratamiento farmacológico , Línea Celular Tumoral , Femenino , Productos del Gen vpr/genética , VIH-1/genética , Células HeLa , Humanos , Leucemia Monocítica Aguda/tratamiento farmacológico , Masculino , Melanoma Experimental/tratamiento farmacológico , Neuroblastoma/tratamiento farmacológico , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias Cutáneas/tratamiento farmacológico , Transducción GenéticaRESUMEN
Chronic viral infection is characterized by the functional impairment of virus-specific T-cell responses. Recent evidence has suggested that the inhibitory receptor programmed death 1 (PD-1) is specifically upregulated on antigen-specific T cells during various chronic viral infections. Indeed, it has been reported that human immunodeficiency virus (HIV)-specific T cells express elevated levels of PD-1 and that this expression correlates with the viral load and inversely with CD4(+) T-cell counts. More importantly, antibody blockade of the PD-1/PD-L1 pathway was sufficient to both increase and stimulate virus-specific T-cell proliferation and cytokine production. However, the mechanisms that mediate HIV-induced PD-1 upregulation are not known. Here, we provide evidence that the HIV type 1 (HIV-1) accessory protein Nef can transcriptionally induce the expression of PD-1 during infection in vitro. Nef-induced PD-1 upregulation requires its proline-rich motif and the activation of the downstream kinase p38. Further, inhibition of Nef activity by p38 MAPK inhibitor effectively blocked PD-1 upregulation, suggesting that p38 MAPK activation is an important initiating event in Nef-mediated PD-1 expression in HIV-1-infected cells. These data demonstrate an important signaling event of Nef in HIV-1 pathogenesis.
Asunto(s)
Antígenos CD/genética , Proteínas Reguladoras de la Apoptosis/genética , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/fisiología , Proteínas Quinasas p38 Activadas por Mitógenos/fisiología , Síndrome de Inmunodeficiencia Adquirida/metabolismo , Antígenos CD/biosíntesis , Proteínas Reguladoras de la Apoptosis/biosíntesis , Linfocitos T CD4-Positivos/metabolismo , Células Cultivadas , Regulación de la Expresión Génica , Humanos , Receptor de Muerte Celular Programada 1 , Regulación hacia ArribaRESUMEN
The Vpr protein of HIV-1 functions as a vital accessory gene by regulating various cellular functions, including cell differentiation, apoptosis, nuclear factor of kappaB (NF-kappaB) suppression and cell-cycle arrest of the host cell. Several reports have indicated that Vpr complexes with the glucocorticoid receptor (GR), but it remains unclear whether the GR pathway is required for Vpr to function. Here, we report that Vpr uses the GR pathway as a recruitment vehicle for the NF-kappaB co-activating protein, poly(ADP-ribose) polymerase-1 (PARP-1). The GR interaction with Vpr is both necessary and sufficient to facilitate this interaction by potentiating the formation of a Vpr-GR-PARP-1 complex. The recruitment of PARP-1 by the Vpr-GR complex prevents its nuclear localization, which is necessary for Vpr to suppress NF-kappaB. The association of GR with PARP-1 is not observed with steroid (glucocorticoid) treatment, indicating that the GR association with PARP-1 is a gain of function that is solely attributed to HIV-1 Vpr. These data provide important insights into Vpr biology and its role in HIV pathogenesis.
Asunto(s)
Núcleo Celular/metabolismo , Productos del Gen vpr/fisiología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Receptores de Glucocorticoides/metabolismo , Transporte Activo de Núcleo Celular , Animales , Antígenos Bacterianos/farmacología , Línea Celular , Chlorocebus aethiops , Enterotoxinas/farmacología , Femenino , Expresión Génica/efectos de los fármacos , Expresión Génica/genética , Productos del Gen vpr/metabolismo , Productos del Gen vpr/farmacología , Infecciones por VIH/metabolismo , Infecciones por VIH/fisiopatología , Células HeLa , Humanos , Quinasa I-kappa B/metabolismo , Proteínas I-kappa B/metabolismo , Interleucina-1/sangre , Interleucina-12/sangre , Células Jurkat , Lipopolisacáridos/farmacología , Ratones , Ratones Endogámicos BALB C , Mifepristona/farmacología , Mutación/genética , Inhibidor NF-kappaB alfa , FN-kappa B/genética , Poli(ADP-Ribosa) Polimerasa-1 , Poli(ADP-Ribosa) Polimerasas/genética , Unión Proteica/efectos de los fármacos , Mapeo de Interacción de Proteínas , ARN Interferente Pequeño/genética , Receptores de Glucocorticoides/genética , Factor de Transcripción ReIA/metabolismo , Transfección , Factor de Necrosis Tumoral alfa/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Células U937 , Productos del Gen vpr del Virus de la Inmunodeficiencia HumanaRESUMEN
The HIV-1 accessory protein Vpr exhibits many interesting features related to macrophage and T cell biology. As a viral protein or as a soluble molecule it can suppress immune cell activation and cytokine production in vitro in part by targeted inhibition of NF-kappaB. In this regard we sought to test its effects in vivo on an NF-kappaB-dependent immune pathway. We examined the activity of Vpr in a lethal toxin-mediated challenge model in mice. Intravenous delivery of Vpr was sufficient to protect mice from lethal challenge with staphylococcal endotoxin B (SEB). Furthermore, Vpr protected host CD4+ T cells from in vivo depletion likely by preventing induction of AICD of SEB-exposed cells in a post-toxin-binding fashion. Understanding the biology of Vpr's activities in this model may allow for new insight into potential mechanisms of hyperinflammatory disease and into Vpr pathobiology in the context of HIV infection.
Asunto(s)
Productos del Gen vpr/inmunología , VIH-1/inmunología , FN-kappa B/inmunología , Linfocitos T/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Citocinas/inmunología , Endotoxinas/farmacología , Femenino , Homeostasis/inmunología , Técnicas In Vitro , Hígado/inmunología , Hígado/patología , Activación de Linfocitos , Recuento de Linfocitos , Ratones , Ratones Endogámicos BALB C , Staphylococcus , Productos del Gen vpr del Virus de la Inmunodeficiencia HumanaRESUMEN
Human immunodeficiency virus-1 (HIV-1) Vpr encodes a 14 kDa protein that has been implicated in viral pathogenesis through in vitro modulation of several host cell functions. Vpr modulates cellular proliferation, cell differentiation, apoptosis and host cell transcription in a manner that involves the glucocorticoid pathway. To better understand the role of HIV-1 Vpr in host gene expression, approximately 9600 cellular RNA transcripts were assessed for their modulation in primary APC after treatment with a bioactive recombinant Vpr (rVpr) by DNA micro-array. As an extracellular delivered protein, Vpr down-modulated the expression of several immunologically important molecules including CD40, CD80, CD83 and CD86 costimulatory molecules on MDM (monocyte-derived macrophage) and MDDC (monocyte-derived dendritic cells). Maturation of dendritic cells (DC) is known to result in a decreased capacity to produce HIV due to a post-entry block of the HIV-1 replicative cycle. Based on the changes observed in the gene array, we analyzed maturation of DC generated from monocytes in tissue culture as influenced by Vpr. We observed that Vpr-treated immature MDM and MDDC were unable to acquire high levels of costimulatory molecules and failed to develop into mature DC, even in the presence of maturation signals. These studies have importance for understanding the interaction of HIV with the host immune system.
Asunto(s)
Células Dendríticas/fisiología , Productos del Gen vpr/farmacología , VIH-1/fisiología , Activación de Macrófagos/fisiología , Macrófagos/fisiología , Fagocitosis/fisiología , Antígenos de Diferenciación/genética , Antígenos de Diferenciación/metabolismo , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/fisiología , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Células Dendríticas/efectos de los fármacos , Perfilación de la Expresión Génica , Productos del Gen vpr/genética , VIH-1/genética , Humanos , Activación de Macrófagos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Análisis de Secuencia por Matrices de Oligonucleótidos , Fagocitosis/genética , Virión/metabolismo , Productos del Gen vpr del Virus de la Inmunodeficiencia HumanaRESUMEN
New and effective approaches for inflammatory diseases based on novel mechanisms of action are needed. One potential source of anti-inflammatory drugs exists among viruses. Viruses have evolved to infect, replicate within, and kill human cells through diverse mechanisms. They accomplish this fact by finding ways to out with the host's complex immune machinery. It is possible that the viral proteins and pathways involved in the downregulation of host immune function during infection can be exploited as a therapeutic in diseases that result in the overactivity of the immune system. Indeed, the human immunodeficiency virus type 1 (HIV-1) protein, Vpr, affects cells in a number of ways that may prove useful for exploitation for the treatment of inflammatory diseases. Vpr has effects on T-cell proliferation, cytokine production, chemokine production, and Nuclear Factor kappa B (NF-kappaB)-mediated transcription. Importantly, it has been observed that Vpr downregulates NF-kappaB and the production of pro-inflammatory cytokines such as TNF-alpha, and IL-12. These activities are worthy of further examination for control of hyperinflammatory and hyperproliferative conditions.