RESUMO
Chemokines are a large family of proteins that, once associated to its receptor on leukocytes, stimulate their movement and migration from blood to tissues. Once in the tissue, immune cells trigger inflammation that, when uncontrolled, leads to fibrosis development. Among the immune cells, macrophages take a special role in fibrosis formation, since macrophage depletion reflects less collagen deposition. The majority of tissue macrophages is derived from monocytes, especially monocytes expressing the chemokine receptor CCR2. Here, we investigated the role of infiltrating CCR2+ cells in the development of fibrosis, and specifically, the dynamic of infiltration of these cells into kidneys under chronic obstructive lesion. Using liposome-encapsulated clodronate, we observed that macrophage depletion culminated in less collagen deposition and reduced chemokines milieu that were released in the damaged kidney after obstructive nephropathy. We also obstructed the kidneys of CCL3-/-, CCR2-/-, CCR4-/-, CCR5-/-, and C57BL/6 mice and we found that among all animals, CCR2-/- mice demonstrated the more robust protection, reflected by less inflammatory and Th17-related cytokines and less collagen formation. Next we evaluated the dynamic of CCR2+/rfp cell infiltration and we observed that they adhere onto the vessels at early stages of disease, culminating in increased recruitment of CCR2+/rfp cells at later stages. On the other hand, CCR2rfp/rfp animals exhibited less fibrosis formation and reduced numbers of recruited cells at later stages. We have experimentally demonstrated that inflammatory CCR2+ cells that reach the injured kidney at initial stages after tissue damage are responsible for the fibrotic pattern observed at later time points in the context of UUO.
Assuntos
Fibrose/patologia , Inflamação/patologia , Nefropatias/patologia , Rim/patologia , Monócitos/patologia , Receptores CCR2/metabolismo , Animais , Colágeno/metabolismo , Citocinas/metabolismo , Fibrose/metabolismo , Inflamação/metabolismo , Rim/metabolismo , Nefropatias/metabolismo , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/metabolismoRESUMO
Chronic kidney disease (CKD) is associated with several other long-lasting conditions such as diabetes and cardiovascular diseases and it is a significant contributor to mortality worldwide. Obstructive kidney disease is one of the leading causes of CKD in children and may result from a wide variety of pathologic processes. Recent studies have shown that α7 nicotinic acetylcholine receptor (α7 nAChR) activation in the cholinergic anti-inflammatory pathway reduces production of inflammatory mediators and consequently prevents tissue injury and death. Here, we examined the role of endogenous release of acetylcholine on the development of fibrosis in renal tissue using a model of unilateral ureter obstruction (UUO)-induced CKD, in which obstruction promotes inflammation-mediated kidney damages. To interfere with acetylcholine secretion, we used mice in which the vesicular acetylcholine transporter is genetically reduced (VAChT KD(hom) mice). We observed a higher renal damage in VAChT mutant mice when compared to wild type controls, exemplified by higher proteinuria and increased amount of type 1 collagen in the kidney tissue, indicating accentuated fibrogenesis. These results were accompanied by enhanced localized kidney inflammation, with increased TH1/TH17 profile response. Administration of PNU-282987, a selective agonist of α7 nAChR, significantly attenuated kidney injury after UUO in VAChT KD(hom) mice, indicating that the lack of acetylcholine release decrease the action of the cholinergic anti-inflammatory pathway, promoting an up-regulation of pro-inflammatory and pro-fibrotic pathways. These results suggest that physiological activation of the cholinergic anti-inflammatory pathway regulates inflammatory responses in the kidney suggesting a new therapeutic approach for kidney disease.
RESUMO
Mesenchymal stromal cells (MSCs) orchestrate tissue repair by releasing cell-derived microvesicles (MVs), which, presumably by small RNA species, modulate global gene expression. The knowledge of miRNA/mRNA signatures linked to a reparative status may elucidate some of the molecular events associated with MSC protection. Here, we used a model of cisplatin-induced kidney injury (acute kidney injury) to assess how MSCs or MVs could restore tissue function. MSCs and MVs presented similar protective effects, which were evidenced in vivo and in vitro by modulating apoptosis, inflammation, oxidative stress, and a set of prosurvival molecules. In addition, we observed that miRNAs (i.e., miR-880, miR-141, miR-377, and miR-21) were modulated, thereby showing active participation on regenerative process. Subsequently, we identified that MSC regulates a particular miRNA subset which mRNA targets are associated with Wnt/TGF-ß, fibrosis, and epithelial-mesenchymal transition signaling pathways. Our results suggest that MSCs release MVs that transcriptionally reprogram injured cells, thereby modulating a specific miRNA-mRNA network.
RESUMO
Focal and segmental glomerulosclerosis (FSGS) is one of the most important renal diseases related to end-stage renal failure. Bradykinin has been implicated in the pathogenesis of renal inflammation, whereas the role of its receptor 2 (B2RBK; also known as BDKRB2) in FSGS has not been studied. FSGS was induced in wild-type and B2RBK-knockout mice by a single intravenous injection of Adriamycin (ADM). In order to further modulate the kinin receptors, the animals were also treated with the B2RBK antagonist HOE-140 and the B1RBK antagonist DALBK. Here, we show that the blockage of B2RBK with HOE-140 protects mice from the development of FSGS, including podocyte foot process effacement and the re-establishment of slit-diaphragm-related proteins. However, B2RBK-knockout mice were not protected from FSGS. These opposite results were due to B1RBK expression. B1RBK was upregulated after the injection of ADM and this upregulation was exacerbated in B2RBK-knockout animals. Furthermore, treatment with HOE-140 downregulated the B1RBK receptor. The blockage of B1RBK in B2RBK-knockout animals promoted FSGS regression, with a less-inflammatory phenotype. These results indicate a deleterious role of both kinin receptors in an FSGS model and suggest a possible cross-talk between them in the progression of disease.
Assuntos
Glomerulosclerose Segmentar e Focal/patologia , Receptores da Bradicinina/fisiologia , Animais , Bradicinina/análogos & derivados , Bradicinina/farmacologia , Glomerulosclerose Segmentar e Focal/metabolismo , Camundongos , Camundongos Knockout , Receptores da Bradicinina/efeitos dos fármacos , Receptores da Bradicinina/genéticaRESUMO
Malaria associated-acute kidney injury (AKI) is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. However, the causes that lead to a framework of malaria-associated AKI are still poorly characterized. Some clinical studies speculate that oxidative stress products, a characteristic of Plasmodium infection, as well as proinflammatory response induced by the parasite are involved in its pathophysiology. Therefore, we aimed to investigate the development of malaria-associated AKI during infection by P. berghei ANKA, with special attention to the role played by the inflammatory response and the involvement of oxidative stress. For that, we took advantage of an experimental model of severe malaria that showed significant changes in the renal pathophysiology to investigate the role of malaria infection in the renal microvascular permeability and tissue injury. Therefore, BALB/c mice were infected with P. berghei ANKA. To assess renal function, creatinine, blood urea nitrogen, and ratio of proteinuria and creatininuria were evaluated. The products of oxidative stress, as well as cytokine profile were quantified in plasma and renal tissue. The change of renal microvascular permeability, tissue hypoxia and cellular apoptosis were also evaluated. Parasite infection resulted in renal dysfunction. Furthermore, we observed increased expression of adhesion molecule, proinflammatory cytokines and products of oxidative stress, associated with a decrease mRNA expression of HO-1 in kidney tissue of infected mice. The measurement of lipoprotein oxidizability also showed a significant increase in plasma of infected animals. Together, our findings support the idea that products of oxidative stress, as well as the immune response against the parasite are crucial to changes in kidney architecture and microvascular endothelial permeability of BALB/c mice infected with P. berghei ANKA.