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Apenas alguns relatos na literatura demonstram que lectinas são importantes nos processos de colonização e infecção por Escherichia coli. A falta de compreensão clara dos mecanismos envolvendo lectinas, no processo de colonização por E. coli, motivou a realização deste estudo para se identificar a presença de outras lectinas não descritas em E. coli. Neste trabalho, isolou-se uma proteína de 75kDa de E. coli em coluna de Sepharose, correspondente ao receptor de aerobactina férrica (IutA). A associação de IutA com virulência de cepas de E. coli é controversa, principalmente em E. coli uropatogênica (UPEC), o que levou a se avaliar a presença do gene iutA em UPECs isoladas de pacientes com infecção urinária. O gene estava presente em 38% dos isolados, sugerindo fraca associação com virulência. Devido à existência de redundância nos sistemas de captura de ferro, sugere-se, aqui, que IutA possa ser vantajosa, mas não essencial para UPEC. La falta de una clara comprensión de los mecanismos de participación de las lectinas en el proceso de colonización por Escherichia coli, nos motivó a identificar la presencia de otras lectinas que no han sido descritas en E. coli. En este estudio, se aisló una proteína de 75kDa de E. coli en una columna de Sepharosa, correspondiente al receptor de aerobactina (IutA). La asociación de IutA con cepas virulentas de E coli es controvertido, especialmente en E. coli uropatógena (UPEC), lo que nos llevó a evaluar la presencia del gen iutA en UPECs aisladas de pacientes con infección urinaria. El gen estaba presente en 38% de los aislamientos, lo que sugiere una débil asociación con la virulencia. Debido a la existencia de redundancia en los sistemas de captura de hierro, se sugiere que IutA puede ser una ventaja, sin embargo no es esencial para la UPEC. Although many proteins have been described involved in Escherichia coli colonization and infection, only few reports have shown lectins as important components in these processes. Because the mechanisms underlying E. coli colonization process involving lectins are not fully understood, we sought to identify the presence of other non-described lectins in E. coli. Here, we isolated a 75-kDa protein from E. coli on Sepharose column and identified it as ferric aerobactin receptor (IutA). Since IutA is controversially associated with virulence of some E. coli strains, mainly in uropathogenic E. coli (UPEC), we evaluated the presence of iutA gene in UPEC isolated from patients with urinary infection. This gene was present in only 38% of the isolates, suggesting a weak association with virulence. Because there is a redundancy in the siderophore-mediated uptake systems, we suggest that IutA can be advantageous but not essential for UPEC.

The microneme organelles of Toxoplasma gondii tachyzoites release protein complexes (MICs), including one composed of the transmembrane protein MIC6 plus MIC1 and MIC4. In this complex, carbohydrate recognition domains of MIC1 and MIC4 are exposed and interact with terminal sialic acid and galactose residues, respectively, of host cell glycans. Recently, we demonstrated that MIC1 and MIC4 binding to the N-glycans of Toll-like receptor (TLR) 2 and TLR4 on phagocytes triggers cell activation and pro-inflammatory cytokine production. Herein, we investigated the requirement for TLR2 heterodimerization and co-receptors in MIC-induced responses, as well as the signaling molecules involved. We used MICs to stimulate macrophages and HEK293T cells transfected with TLR2 and TLR1 or TLR6, both with or without the co-receptors CD14 and CD36. Then, the cell responses were analyzed, including nuclear factor-kappa B (NF-κB) activation and cytokine production, which showed that (1) only TLR2, among the studied factors, is crucial for MIC-induced cell activation; (2) TLR2 heterodimerization augments, but is not critical for, activation; (3) CD14 and CD36 enhance the response to MIC stimulus; and (4) MICs activate cells through a transforming growth factor beta-activated kinase 1 (TAK1)-, mammalian p38 mitogen-activated protein kinase (p38)-, and NF-κB-dependent pathway. Remarkably, among the studied factors, the interaction of MIC1 and MIC4 with TLR2 N-glycans is sufficient to induce cell activation, which promotes host protection against T. gondii infection.

O aparecimento de efeitos adversos associados ao uso dos corticosteroides tem impulsionado a busca de compostos derivados de produtos naturais com propriedades farmacológicas, para que possam ser usados como alternativa terapêutica anti-inflamatória. Dessa forma, o presente estudo buscou avaliar o potencial anti-inflamatório da caulerpina (CLP), alcaloide derivado de algas do gênero Caulerpa, nos modelos murinos de peritonite induzida por zimosan e edema de orelha induzido por xileno. Para isso, camundongos foram tratados oralmente com CLP nas doses de 4, 2, 1 mg/kg e dexametasona (1mg/kg) e 1 hora depois receberam zimosan (40 mg/kg) por via intraperitoneal. Decorridas 24 horas, foi coletado o lavado peritoneal e determinado o número de células. O mesmo procedimento foi repetido para avaliar a cinética de migração e a presença de citocinas no lavado peritoneal nos tempos de 6, 24 e 48 horas. Para o edema de orelha, os animais foram tratados com mesmas diferentes doses de CLP, seguido pela aplicação tópica do xileno (40μL) nas orelhas direitas, 1 hora após o tratamento. O nível de edema foi determinado a partir do cálculo do percentual de inibição e análise morfológica avaliados em secções iguais das orelhas removidas. No modelo de peritonite, o pré-tratamento com CLP reduziu a migração celular para a cavidade peritoneal nas doses de 4, 2 e 1 mg/kg, sendo a dose de 2 mg/kg a que apresentou resultado mais expressivo na inibição da migração celular. Na cinética de migração celular, usando a dose de 2 mg/kg de CLP, observou-se que essa foi capaz de inibir esse evento nos três tempos avaliados, após a administração do zimosan. E esse efeito se relacionou com a diminuição dos níveis de IL-1β e IL-6 no lavado peritoneal, durante a cinética estudada. No modelo de edema, observou-se que as três doses de CLP testadas agiram inibindo a formação do edema de orelha induzido por xileno, o que foi demonstrado através dos altos percentuais de inibição do processo (baseado no peso das secções das orelhas) e na preservação da morfologia tecidual das orelhas nos animais que receberam os tratamentos, sendo a dose de 2 mg/kg a que se mostrou mais eficiente nessa inibição. Assim, a CLP apresenta atividade anti-inflamatória nos modelos estudados e a dose de 2 mg/kg apresenta-se como dose-ótima em controlar a inflamação nos modelos de peritonite induzida por zimosan e edema de orelha induzido por xilol. The appearance of adverse effects associated with the use of corticosteroids has driven the search for compounds derived from natural products with pharmacological properties, so that they can be used as an alternative anti-inflammatory therapy. Thus, the present study sought to assess the anti-inflammatory potential of caulerpin (CLP), an alkaloid derived from algae of the genus Caulerpa, in murine models of zimosaninduced peritonitis and xylene-induced ear edema. For this, mice were orally treated with CLP at doses of 4, 2, 1 mg/kg and dexamethasone (1 mg/kg) and 1 hour later received zymosan (40 mg/kg) intraperitoneally. After 24 hours, the peritoneal lavage was collected and the number of cells was determined. The same procedure was repeated to assess the migration kinetics and presence of cytokines in the peritoneal lavage at 6, 24 and 48 hours. For ear edema, the animals were treated with the same different doses of CLP, followed by topical application of xylene (40μL) in the right ears, 1 hour after treatment. The level of edema was determined by calculating the percentage of inhibition and morphological analysis evaluated in equal sections of the removed ears. In the peritonitis model, pre-treatment with CLP was able to reduce cell migration to the peritoneal cavity at doses of 4, 2 and 1 mg/kg, with the dose of 2 mg/kg being the one that showed results more expressive in inhibiting cell migration. In the cell migration kinetics, using the dose of 2 mg/kg of CLP, it was observed that this dose was able to inhibit this event in the three evaluated times, after the administration of zymosan. And this effect was related to the decrease in the levels of IL-1β and IL-6 in the peritoneal lavage, during the studied kinetics. In the edema model, it was observed that the three CLP doses tested acted by inhibiting the formation of xylene-induced ear edema, which was demonstrated by the high percentages of inhibition of the process (based on the weight of the ear sections) and in the preservation of the tissue morphology of the ears in the animals that received the treatments, with the dose of 2 mg/kg being the most efficient in this inhibition. Thus, the CLP has anti-inflammatory activity in the models studied and the dose of 2 mg/kg is an optimal dose in controlling inflammation in the models of peritonitis induced by zimosan and xylol-induced ear edema.