RESUMEN
OBJECTIVE: Clostridium perfringens causes food poisoning and gas gangrene, a serious wound-associated infection. C. perfringens cells adhere to collagen via fibronectin (Fn). We investigated whether the peptidoglycan hydrolase of C. perfringens, i.e., autolysin (Acp), is implicated in Fn binding to C. perfringens cells. METHODS: This study used recombinant Acp fragments, human Fn and knockout mutants (C. perfringens 13 acp::erm and HN13 ΔfbpC ΔfbpD). Ligand blotting, Western blotting analysis, and complementation tests were performed. The Fn-binding activity of each mutant was evaluated by ELISA. RESULTS: From an Fn-binding assay using recombinant Acp fragments, Fn was found to bind to the catalytic domain of Acp. In mutant cells lacking Acp, Fn binding was significantly decreased, but was restored by the complementation of the acp gene. There are three known kinds of Fn-binding proteins in C. perfringens: FbpC, FbpD, and glyceraldehyde-3-phosphate dehydrogenase. We found no difference in Fn-binding activity between the mutant cells lacking both FbpC and FbpD (SAK3 cells) and the wild-type cells, indicating that these Fn-binding proteins are not involved in Fn binding to C. perfringens cells. CONCLUSIONS: We found that the Acp is an Fn-binding protein that acts as an Fn receptor on the surface of C. perfringens cells.
Asunto(s)
Clostridium perfringens , Gangrena Gaseosa , Humanos , Clostridium perfringens/genética , Clostridium perfringens/metabolismo , N-Acetil Muramoil-L-Alanina Amidasa/genética , N-Acetil Muramoil-L-Alanina Amidasa/metabolismo , Integrina alfa5beta1/metabolismo , Unión Proteica , Proteínas Portadoras/metabolismoRESUMEN
BACKGROUND: The parasite Entamoeba histolytica is the causal agent of amoebiasis, a worldwide emerging disease. Amebic brain abscess is a form of invasive amebiasis that is both rare and frequently lethal. This condition always begins with the infection of the colon by E. histolytica trophozoites, which subsequently travel through the bloodstream to extraintestinal tissues. CASE PRESENTATION: We report a case of a 71-year-old female who reported an altered state of consciousness, disorientation, sleepiness and memory loss. She had no history of hepatic or intestinal amoebiasis. A preliminary diagnosis of colloidal vesicular phase neurocysticercosis was made based on nuclear magnetic resonance imaging (NMRI). A postsurgery immunofluorescence study was positive for the 140 kDa fibronectin receptor of E. histolytica, although a serum analysis by ELISA was negative for IgG antibodies against this parasite. A specific E. histolytica 128 bp rRNA gene was identified by PCR in biopsy tissue. The final diagnosis was cerebral amoebiasis. The patient underwent neurosurgery to eliminate amoebic abscesses and was then given a regimen of metronidazole, ceftriaxone and dexamethasone for 4 weeks after the neurosurgery. However, a rapid decline in her condition led to death. CONCLUSIONS: The present case of an individual with a rare form of cerebral amoebiasis highlights the importance of performing immunofluorescence, NMRI and PCR if a patient has brain abscess and a poorly defined diagnosis. Moreover, the administration of corticosteroids to such patients can often lead to a rapid decline in their condition.
Asunto(s)
Absceso Encefálico/diagnóstico , Absceso Encefálico/parasitología , Infecciones Parasitarias del Sistema Nervioso Central/diagnóstico , Entamebiasis/diagnóstico , Anciano , Animales , Absceso Encefálico/tratamiento farmacológico , Absceso Encefálico/cirugía , Ceftriaxona/administración & dosificación , Infecciones Parasitarias del Sistema Nervioso Central/tratamiento farmacológico , Infecciones Parasitarias del Sistema Nervioso Central/patología , Infecciones Parasitarias del Sistema Nervioso Central/cirugía , Terapia Combinada , ADN Protozoario/análisis , Dexametasona/administración & dosificación , Quimioterapia Combinada , Entamoeba histolytica/genética , Entamoeba histolytica/inmunología , Entamoeba histolytica/aislamiento & purificación , Entamebiasis/tratamiento farmacológico , Entamebiasis/patología , Entamebiasis/cirugía , Resultado Fatal , Femenino , Humanos , Metronidazol/administración & dosificación , Procedimientos Neuroquirúrgicos , Pruebas SerológicasRESUMEN
At diagnosis, 10 % of breast cancer patients already have locally advanced or metastatic disease; moreover, metastasis eventually develops in at least 40 % of early breast cancer patients. Osteolytic bone colonization occurs in 80-85 % of metastatic breast cancer patients and is thought to be an early step in metastatic progression. Thus, breast cancer displays a strong preference for metastasis to bone, and most metastatic breast cancer patients will experience its complications. Our prior research has shown that the α5ß1 integrin fibronectin receptor mediates both metastatic and angiogenic invasion. We invented a targeted peptide inhibitor of activated α5ß1, Ac-PHSCN-NH2 (PHSCN), as a validated lead compound to impede both metastatic invasion and neovascularization. Systemic PHSCN monotherapy prevented disease progression for up to 14 months in Phase I clinical trial. Here, we report that the next-generation construct, Ac-PhScN-NH2 (PhScN), which contains D-isomers of histidine (h) and cysteine (c), is greater than 100,000-fold more potent than PHSCN at blocking basement membrane invasion. Moreover, PhScN is also up to 10,000-fold more potent than PHSCN at inhibiting lung extravasation and colonization in athymic mice for both MDA-MB-231 metastatic and SUM149PT inflammatory breast cancer cells. Furthermore, we show that systemic treatment with 50 mg/kg PhScN monotherapy reduces established intratibial MDA-MB-231 bone colony progression by 80 %. Thus, PhScN is a highly potent, well-tolerated inhibitor of both lung colonization and bone colony progression.
Asunto(s)
Antineoplásicos/administración & dosificación , Neoplasias Óseas/tratamiento farmacológico , Neoplasias de la Mama/tratamiento farmacológico , Integrina alfa5beta1/antagonistas & inhibidores , Neoplasias Pulmonares/tratamiento farmacológico , Oligopéptidos/administración & dosificación , Animales , Antineoplásicos/farmacología , Neoplasias Óseas/metabolismo , Neoplasias Óseas/secundario , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Progresión de la Enfermedad , Femenino , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundario , Ratones , Oligopéptidos/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Earlier studies reported allelic deletion of the essential autophagy regulator BECN1 in breast cancers implicating BECN1 loss, and likely defective autophagy, in tumorigenesis. Recent studies have questioned the tumor suppressive role of autophagy, as autophagy-related gene (Atg) defects generally suppress tumorigenesis in well-characterized mouse tumor models. We now report that, while it delays or does not alter mammary tumorigenesis driven by Palb2 loss or ERBB2 and PyMT overexpression, monoallelic Becn1 loss promotes mammary tumor development in 2 specific contexts, namely following parity and in association with wingless-type MMTV integration site family, member 1 (WNT1) activation. Our studies demonstrate that Becn1 heterozygosity, which results in immature mammary epithelial cell expansion and aberrant TNFRSF11A/TNR11/RANK (tumor necrosis factor receptor superfamily, member 11a, NFKB activator) signaling, promotes mammary tumorigenesis in multiparous FVB/N mice and in cooperation with the progenitor cell-transforming WNT1 oncogene. Similar to our Becn1(+/-);MMTV-Wnt1 mouse model, low BECN1 expression and an activated WNT pathway gene signature correlate with the triple-negative subtype, TNFRSF11A axis activation and poor prognosis in human breast cancers. Our results suggest that BECN1 may have nonautophagy-related roles in mammary development, provide insight in the seemingly paradoxical roles of BECN1 in tumorigenesis, and constitute the basis for further studies on the pathophysiology and treatment of clinically aggressive triple negative breast cancers (TNBCs).
Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Neoplasias Mamarias Animales/metabolismo , Proteína Wnt1/metabolismo , Alelos , Animales , Apoptosis , Autofagia , Beclina-1 , Neoplasias de la Mama/metabolismo , Proliferación Celular , Células Epiteliales/citología , Femenino , Regulación Neoplásica de la Expresión Génica , Heterocigoto , Humanos , Neoplasias Mamarias Experimentales/metabolismo , Proteínas de la Membrana/metabolismo , Ratones , Ratones Desnudos , Análisis de Secuencia por Matrices de Oligonucleótidos , Transducción de Señal , Células Madre/citología , Neoplasias de la Mama Triple Negativas/metabolismoRESUMEN
Pathophysiological mechanism of hemorrhagic fever with renal syndrome (HFRS) is not fully understood. Major clinical findings of HFRS patients are widespread hemorrhage, acute renal failure and shock. Basic lesion is vascular injury with microvascular hemorrhage and relatively little inflammation. According to autopsy findings, renal medulla shows focal hemorrhage, tubular necrosis and interstitial mononuclear infiltrates. The predominant cell type in the renal and pulmonary interstitium is a fibroblast and it participates in the healing process at the injury site by secreting a large amount of extracellular matrix proteins. Cultured human lung fibroblasts and Mongolian gerbil fibroblasts were known to be good host cells for the hantaan virus. It is possible that not only the endothelial cell but also the fibroblast is a target of Hantaan virus and the fibroblast might be involved in the pathogenesis and the healing process in HFRS. Integrins are adhesion molecules, and act as receptors for many extracellular matrix proteins. Recently, there are many reports that cell surface integrins influence on some viral infections or reversely viruses influence on the expression of integrins. The alpha5beta1 integrin is a major receptor for the fibronectin which is an important extracellular matrix protein secreted by fibroblasts. In this study, the role of alpha5beta1 integrin in the infection of Hantaan virus was examined by using anti-alpha5beta1 integrin, anti-alpha5 integrin and anti-beta1 integrin antibodies in chicken embryo fibroblasts (CEF) and Mongolian gerbil fibroblasts(MGF). The treatment of anti-alpha5beta1 integrin antibody in CEF reduced the virion titers 26.8% and the amount of nucleocapsid N protein 32.6% when compared with control CEF. When MGF were treated with anti-alpha5, anti-beta1 and anti-alpha5beta1 integrin antibodies, virion titers were reduced by 26.5%, 29.4% and 28.7% and the amount of nucleocapsid N protein were reduced by 65.2%, 59.7% and 72.6%. These results suggested that alpha5beta1 integrin might act as a receptor for the Hantaan virus or blocking of alpha5beta1 integrin influences on the viral replication in CEF and MGF. It is also possible that the blocking of only one subunit of integrin represents similar results in that of whole molecule.