Role of Gut Microbiota in Dengue.

Dengue is a disease caused by a flavivirus (DENV) and transmitted by the bite of a mosquito, primarily the Aedes aegypti and Aedes albopictus species. Previous studies have demonstrated a relationship between the host gut microbiota and the evolution of dengue. It seems to be a bidirectional relationship, in which the DENV can affect the microbiota by inducing alterations related to intestinal permeability, leading to the release of molecules from microbiota dysbiosis that can influence the evolution of dengue. The role of angiotensin II (Ang II) in the microbiota/dengue relationship is not well understood, but it is known that the renin-angiotensin system (RAS) is present in the intestinal tract and interacts with the gut microbiota. The possible effect of Ang II on the microbiota/Ang II/dengue relationship can be summarised as follows: the presence of Ang II induced hypertension, the increase in angiotensinogen, chymase, and microRNAs during the disease, the induction of vascular dysfunction, the production of trimethylamine N-oxide and the brain/microbiota relationship, all of which are elements present in dengue that could be part of the microbiota/Ang II/dengue interactions. These findings suggest the potential use of Ang II synthesis blockers and the use of AT1 receptor antagonists as therapeutic drugs in dengue.

In situ immunopathological events in human cervical intraepithelial neoplasia and cervical cancer: Review.

Neoplasia of the cervix represents one of the most common cancers in women. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. The in-situ expression of several cytokines by uterine epithelial cells and by infiltrating leukocytes occurs during the cervical intraepithelial neoplasia and cervical cancer. Some of these cytokines can prevent and others can induce the progression of the neoplasm. The infiltrating leukocytes also produce cytokines and growth factors relate to angiogenesis, chemotaxis, and apoptosis capable of modulating the dysplasia progression. In this review we analyzed several interleukins with an inductive effect or blocking effect on the neoplastic progression. We also analyze the genetic polymorphism of some cytokines and their relationship with the risk of developing cervical neoplasia. In addition, we describe the leukocyte cells that infiltrate the cervical uterine tissue during the neoplasia and their effects on neoplasia progression.

In situ expressions of protein 16 (p16CDKN2A) and transforming growth factor beta-1 in patients with cervical intraepithelial neoplasia and cervical cancer.

OBJECTIVES: Protein 16 (p16CDKN2A) and transforming growth factor-beta 1 (TGF- ß1) are important tumor suppressor molecules. The aim of this study was to evaluate the frequency and simultaneous expression of p16CDKN2A and TGF- ß1 in cervical intraepithelial neoplasia (CIN) and cervical cancer and their relationship whit the neoplasia progression. STUDY DESIGN: To evaluate the expressions of p16CDKN2A and TGF- ß1 an immunohistochemical study of both proteins in 75 cervical tissues (24 CIN I, 17 CIN II, 15 CIN III and 19 squamous cell cancer) was performed. RESULTS: Increased expression of epithelial and stromal p16CDKN2A in all grades of CIN and cancer was observed. Healthy controls were negative. The frequency of p16CDKN2A expression in the patients was as follow: 75% in CIN I and 100% in CIN II, CIN III and cancer. TGF- ß1 expression was found increased in all patients with CIN I and CIN II and decreased in CIN III and cancer; 60% of patients with CIN III and 16% with cancer showed reactivity for TGF- ß1. High intensity of p16CDKN2A reactivity and low intensity of TGF- ß1 reactivity were observed. CONCLUSIONS: The linear frequency of p16CDKN2A expression accompanied by decreased frequency of TGF- ß1 in CIN III and cancer could be involved in the neoplasia progression.

[Role of the receptor for advanced glycation end products (RAGE) in inflammation]. / Papel del receptor para compuestos de glicosilación avanzada (RAGE) en la inflamación.

The receptor for advanced glycation end products (RAGE) is a transmembrane protein on the cellular surface that recognizes tridimensional molecules, instead of aminoacid sequences, making this molecule capable of interacting with diverse ligands. RAGE represents an important factor in innate immunity against pathogens, but it also interacts with endogenous ligands, resulting in chronic inflammation. RAGE signaling has been implicated in multiple human illnesses, including diabetes, atherosclerosis, arthritis, Alzheimer's disease, atherosclerosis and aging associated diseases. In addition to advanced glycation end products (AGE), RAGE has other important ligands such as: high mobility group box 1 protein (HMGB1, also termed amphoterin), the group of calcium binding cellular factors S100 (also termed calgranulin), amiloid beta peptides and Mac-1, a beta-2 integrin (CD1lb/CD18). Ligation of RAGE on the cellular surface triggers a series of cellular signaling events, including the activation and translocation to the nucleus of transcription factor NF-kappaB, leading to the production of pro-inflammatory cytokines, chemokines, adhesion molecules and oxidative stress and causing inflammation. More recent work has revealed the role of RAGE in inflammatory cell recruitment and extravasation of leukocytes across the endothelial barrier with further inflammatory events. Recent therapeutic strategies show that RAGE is an important target to treat RAGE activation-associated diseases.

Papel del receptor para compuestos de glicosilación avanzada (RAGE) en la inflamación: [revisión] / Role of the receptor for advanced glycation end products (RAGE) in inflammation: [revisión]

Los receptores para los compuestos de glicosilación avanzada (RAGE) son moléculas ubicadas en la superficie celular (transmembrana), que interactúan con patrones moleculares tridimensionales, más que con secuencia de aminoácidos, lo que los hace adecuados para unirse a varios ligandos. Estos receptores representan un elemento importante en la inmunidad innata contra patógenos, pero también interactúan con ligandos endógenos originando inflamación crónica. Esta característica los hace potenciales inductores de enfermedades asociadas a la inflamación crónica como la diabetes, la enfermedad de Alzheimer, artritis, ateroesclerosis y trastornos degenerativos relacionados con la vejez. Los principales ligandos de RAGE aparte de los compuestos de glicosilación, son las proteínas de alta movilidad del grupo de caja 1 (HMGB1; llamada también Anfoterina), las proteínas del grupo S100 que fijan calcio, también llamadas calgranulinas, los péptidos amiloides β y el Mac-1, una beta-2 integrina (CD11b/CD18). La unión de RAGE con su ligando en la superficie celular induce la activación de varias vías de señalización intracelular que llevan como punto central, a la translocación del factor de transcripcion NF-κB del citoplasma al núcleo, éste al actuar sobre el ADN, induce la producción de moléculas de adhesión, citocinas, quimiocinas y estrés oxidativo, entre otros efectos. Además de inducir las señalizaciones, la molécula per se es capaz de actuar como un receptor de otras moléculas en el endotelio y permitir la extravasación y la infiltración de leucocitos a los tejidos, aumentando el fenómeno inflamatorio. Estudios recientes demuestran que RAGE es un blanco terapéutico importante para el tratamiento de las enfermedades asociadas a su activación.

The receptor for advanced glycation end products (RAGE) is a transmembrane protein on the cellular surface that recognizes tridimensional molecules, instead of aminoacid sequences, making this molecule capable of interacting with diverse ligands. RAGE represents an important factor in innate immunity against pathogens, but it also interacts with endogenous ligands, resulting in chronic inflammation. RAGE signaling has been implicated in multiple human illnesses, including diabetes, atherosclerosis, arthritis, Alzheimer's disease, atherosclerosis and aging associated diseases. In addition to advanced glycation end products (AGE), RAGE has other important ligands such as: high mobility group box 1 protein (HMGB1, also termed amphoterin), the group of calcium binding cellular factors S100 (also termed calgranulin), amiloid beta peptides and Mac-1, a beta-2 integrin (CD11b/CD18). Ligation of RAGE on the cellular surface triggers a series of cellular signaling events, including the activation and translocation to the nucleus of transcription factor NF-κB, leading to the production of pro-inflammatory cytokines, chemokines, adhesion molecules and oxidative stress and causing inflammation. More recent work has revealed the role of RAGE in inflammatory cell recruitment and extravasation of leukocytes across the endothelial barrier with further inflammatory events. Recent therapeutic strategies show that RAGE is an important target to treat RAGE activation-associated diseases.

Increased expression of apoptosis-associated proteins in puromycin aminonucleoside nephrosis.

Increased apoptosis has been reported in acute puromycin aminonucleoside nephrosis (PAN). The aim of this study was to investigate if increased apoptosis is related to increased expression of apoptosis-associated proteins (AAP) in this model of nephrosis. Sprague-Dawley rats were made nephrotic by intraperitoneal injection of one dose of puromycin aminonucleoside. Renal tissues were obtained at 1, 2 and 7 weeks after injection and apoptosis was investigated by TUNEL and by electron microscopy. Fas, Fas ligand, p53, Bax and Bcl-2 expressions were analyzed by the respective monoclonal and polyclonal antibodies, using indirect immunofluorescence. In the glomerulus of nephrotic animals, increased apoptosis was accompanied with increased expression of p53, Fas and Bax. In the interstitium, high expression of apoptosis, Fas, Fas-L and Bax were observed and in tubules increased apoptosis was accompanied with increased expression of p53, Fas and Fas-L. Bcl-2 was increased in interstitium and tubules during PAN. The incidence of apoptosis during PAN was correlated with the expression of AAP in glomerulus (p53), interstitium (Fas, Fas-L and Bax) and tubules (Fas, Fas-L, p53 and Bcl-2). There was correlation between Fas and Fas-L expression in interstitium and tubules. About 4% of glomerular and 25% of tubular p53 positive cells were apoptotic cells. The data suggest that increased local expression of AAP could contribute to renal apoptosis in the glomerular, interstitial and tubular compartments during this experimental model of nephrosis.

Increased expression of apoptosis-associated proteins in puromycin aminonucleoside nephrosis

Estudios previos han demostrado la presencia de apoptosis en el tejido renal de ratas con nefrosis por aminonucleósido de puromicina (NAP). Este estudio está orientado a determinar si la expresión de la apoptosis está relacionada con aumento en la expresión de proteínas asociadas a la apoptosis (PAP) durante el curso de NAP. Se utilizaron ratas Sprague. Dawley las cuales fueron hechas nefróticas con una inyección única intraperitoneal de aminonucleósido de puromicina. Los controles fueron ratas inyectadas sólo con el vehículo. Se obtuvieron tejidos renales a las 1, 2 y 7 semanas después de la inyección y se analizó la apoptosis por TUNEL y microscopia electrónica y Fas, Fas-L, p53, Bax y Bcl-2 mediante la inmunofluorescencia indirecta, usando anticuerpos policlónales y monoclonales. Se encontró incremento en la apoptosis en el glomérulo de los animales con NAP, acompañado con incremento en la expresión de p53, Fas y Bax. En el intersticio se incrementaron la apoptosis y la expresión de Fas, Fas-L y Bax y en los túbulos el aumento de la apoptosis se acompañó de aumento de p53, Fas, Fas-L. Bcl-2 se incrementó en intersticio y túbulos. La incidencia de apoptosis en este modelo estuvo correlacionada con la expresión de PAP en glomérulo (p53), intersticio (Fas, Fas-L y Bax) y en túbulos (Fas, Fas-L, p53 y Bcl-2). Hubo correlación entre las expresiones de Fas y Fas-L en intersticio y túbulos. Cerca del 4 por ciento en el glomérulo y el 25 por ciento en túbulos de las células p53 positivas estaban en apoptosis. Estos datos sugieren que una expresión aumentada de las PAP en glomérulo, intersticio y túbulo puede estar relacionada con el incremento de la apoptosis en los diferentes compartimientos renales durante este modelo experimental

Ultrastructural studies on dengue virus type 2 infection of cultured human monocytes.

BACKGROUND: Early interaction of dengue virus and monocyte/macrophages could be an important feature for virus dissemination after its initial entry via the mosquito vector. Since ultrastructural analysis of this interaction has not been reported, dengue type 2 (DEN2) virus-infected human monocyte cultures were studied at 1, 2, 4 and 6 hours after infection. RESULTS: Typical dengue particles and fuzzy coated viral particles were 35 to 42 nm and 74 to 85 nm respectively. Viruses were engulfed by phagocytosis and macropicnocytosis leading to huge vacuoles and phagosomes inside the monocytes. Interaction of monocytes with DEN2 virus induced apoptosis, characterized by nuclear condensation and fragmentation, cellular shrinkage, blebbing and budding phenomena and phagocytosis of apoptotic cells by neighboring monocytes. This finding was confirmed by TUNEL. Ultrastructural features associated to DEN2 virus replication were not observed. CONCLUSION: These data suggest that clearance of the virus by monocytes and cellular death are the main features during the initial interaction of DEN2 virus and monocytes and this could be important in the rapid elimination of the virus after infection by mosquito vector.

Increased production of chemotactic cytokines and elevated proliferation and expression of intercellular adhesion molecule-1 in rat mesangial cells treated with erythrogenic toxin type B and its precursor isolated from nephritogenic streptococci.

BACKGROUND: Previous reports have demonstrated the presence of streptococcal erythrogenic toxin type B (ETB) as well as proliferation and expression of adhesion molecules along with leukocyte infiltrations in biopsies from patients with acute post-streptococcal glomerulonephritis (APSGN). The purpose of the present study was to correlate infiltrative and proliferative events with interactions between ETB or its precursor (ETBP) and intrinsic mesangial cells. METHODS: Rat mesangial cells were cultured with ETB or ETBP (50 micro g/ml) while measuring production of monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) and while examining proliferation and expression of intercellular adhesion molecule-1 (ICAM-1). After 24, 48 and 96 h of incubation, MCP-1 and MIP-2 in culture supernatants were assessed by enzyme-linked immunosorbent assay (ELISA). Cells were assessed for proliferation by incorporation of radioactive thymidine and expression of ICAM-1 was measured by indirect immunofluorescence and by cellular ELISA. RESULTS: Compared with controls, treatment with either ETBP or ETB significantly increased MCP-1 and MIP-2 levels in mesangial cell cultures. Mesangial cells also showed elevated proliferation at 96 h of culture when treated with streptococcal proteins. Although production of MCP-1 and MIP-2 was not correlated with proliferation, treatment with ETBP resulted in a significant correlation between MCP-1 production and proliferation. Immunofluorescence studies revealed an increased expression of ICAM-1 in ETBP/ETB-treated mesangial cells. In addition, cellular ELISA studies showed increased absorbance in cultures treated with ETBP/ETB. Finally, low serum concentrations in the culture medium potentiated the stimulatory effect of ETB on MCP-1 production. CONCLUSIONS: Our findings, by demonstrating a role for cationic streptococcal ETB or ETBP in the induction of chemotactic molecules as well as the proliferation and expression of adhesion molecules, delineate an additional possible pathway for the pathogenesis of APSGN.

Increased apoptosis and expression of tumor necrosis factor-alpha caused by infection of cultured human monocytes with dengue virus.

Dengue (DEN) virus is responsible for one of the most significant viral diseases in tropical countries. Monocytes/macrophages (Mo/Mphi) are the major target cells for DEN virus. To determine the effects of the interaction between DEN virus and Mo/Mphi, human monocyte cultures were infected with DEN virus type 2. Apoptosis and production of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide were measured in control and infected cultures. Virus was taken up by phagocytosis, but no membrane-coated pits at the virus attachment sites were observed. Increased number of apoptotic cells and increased production of TNF-a were observed in infected monocyte cultures. No increase in production of nitric oxide was observed. These results may be related to early primary viral infection, in which virus could induce apoptosis in monocytes, but monocytes may contribute to host defense mechanisms against virus by viral phagocytosis, phagocytosis of infected apoptotic cells, and the release of proinflammatory cytokines.

Short report: increased level of serum nitric oxide in patients with dengue.

Nitric oxide (NO) has been involved in several infectious diseases. Virus dengue is capable of inducing increased levels of NO when cocultured with human Kupffer and spleen cells. However, no reports describe the levels of NO in patients with dengue infection. Increased levels of NO were found in patients with the classic form of the disease; however, in the hemorrhagic form of the disease, similar levels to those of healthy controls were found. In vitro studies showed no increased levels of NO when human platelets were incubated with the virus. Increased NO in classical dengue could be important in the evolution from the nonhemorrhagic to the hemorrhagic forms of dengue.

Interleukin-1 increases fibronectin production by cultured rat cardiac fibroblasts.

OBJECTIVES: There is evidence of monocyte/macrophage infiltration and increased interleukin (IL)-1 expression, along with increased extracellular matrix (ECM) and fibrosis in the myocardial interstitium, during the course of parasitic, viral and idiopathic myocarditis. The aim of this study was to determine the effect of human and rat IL-1 on the production of fibronectin (FN) by rat cardiac fibroblast cultures. METHODS: To test the role of IL-1 in the production of ECM, we determined the FN content in supernatants of rat myocardial fibroblast cultures incubated for 72 h with different doses of human recombinant IL-1beta or with supernatants from lipopolysaccharide (LPS)-stimulated rat macrophage cultures. The content of soluble FN was determined by ELISA. In addition, IL-1beta transcription was also investigated in controls and human recombinant IL-1beta-treated fibroblast cultures. RESULTS: There was a significant, dose-dependent FN-stimulatory effect of recombinant human IL-1beta and LPS-stimulated macrophage-conditioned medium when they were used to stimulate fibroblast cultures. The stimulatory effect on FN production was found to be diminished after treatment of macrophage supernatants with an antibody against rat IL-1. Increased transcription of IL-1beta was found in human recombinant IL-1beta-treated cardiac fibroblasts. CONCLUSION: Our data suggest that the FN-stimulatory effect of IL-1 on cardiac fibroblasts could be responsible, in part, for interstitial ECM accumulation during the course of myocarditis.