DDR1 and Its Ligand, Collagen IV, Are Involved in In Vitro Oligodendrocyte Maturation.

Discoidin domain receptor 1 (DDR1) is a tyrosine kinase receptor expressed in epithelial cells from different tissues in which collagen binding activates pleiotropic functions. In the brain, DDR1 is mainly expressed in oligodendrocytes (OLs), the function of which is unclear. Whether collagen can activate DDR1 in OLs has not been studied. Here, we assessed the expression of DDR1 during in vitro OL differentiation, including collagen IV incubation, and the capability of collagen IV to induce DDR1 phosphorylation. Experiments were performed using two in vitro models of OL differentiation: OLs derived from adult rat neural stem cells (NSCs) and the HOG16 human oligodendroglial cell line. Immunocytofluorescence, western blotting, and ELISA were performed to analyze these questions. The differentiation of OLs from NSCs was addressed using oligodendrocyte transcription factor 2 (Olig2) and myelin basic protein (MBP). In HOG16 OLs, collagen IV induced DDR1 phosphorylation through slow and sustained kinetics. In NSC-derived OLs, DDR1 was found in a high proportion of differentiating cells (MBP+/Olig2+), but its protein expression was decreased in later stages. The addition of collagen IV did not change the number of DDR1+/MBP+ cells but did accelerate OL branching. Here, we provide the first demonstration that collagen IV mediates the phosphorylation of DDR1 in HOG16 cells and that the in vitro co-expression of DDR1 and MBP is associated with accelerated branching during the differentiation of primary OLs.

Amelioration of exosome and mesenchymal stem cells in rats infected with diabetic nephropathy by attenuating early markers and aquaporin-1 expression / Melhoria das células-tronco exossomais e mesenquimais em ratos infectados com nefropatia diabética atenuando marcadores precoces e expressão de aquaporina-1

Diabetic nephropathy (DN) is a prevalent diabetic microvascular condition. It is the leading cause of kidney disease in the advanced stages. There is no currently effective treatment available. This research aimed to investigate the curative potentials of exosomes isolated from mesenchymal stem cells affecting DN. This study was performed on 70 male adult albino rats. Adult rats were randomized into seven groups: Group I: Negative control group, Group II: DN group, Group III: Balanites treated group, Group IV: MSCs treated group, Group V: Exosome treated group, Group VI: Balanites + MSCs treated group and Group VII: Balanites + exosome treated group. Following the trial period, blood and renal tissues were subjected to biochemical, gene expression analyses, and histopathological examinations. Results showed that MDA was substantially increased, whereas TAC was significantly decreased in the kidney in the DN group compared to normal health rats. Undesired elevated values of MDA levels and a decrease in TAC were substantially ameliorated in groups co-administered Balanites aegyptiacae with MSCs or exosomes compared to the DN group. A substantial elevation in TNF-α and substantially diminished concentration of IGF-1 were noticed in DN rats compared to normal health rats. Compared to the DN group, the co-administration of Balanites aegyptiacae with MSCs or exosomes substantially improved the undesirable elevated values of TNF-α and IGF-1. Furthermore, in the DN group, the mRNA expression of Vanin-1, Nephrin, and collagen IV was significantly higher than in normal healthy rats. Compared with DN rats, Vanin-1, Nephrin, and collagen IV Upregulation were substantially reduced in groups co-administered Balanites aegyptiacae with MSCs or exosomes. In DN rats, AQP1 expression was significantly lower than in normal healthy rats. Furthermore, the groups co-administered Balanites aegyptiacae with MSCs or exosomes demonstrated a substantial increase in AQP1 mRNA expression compared to DN rats.

A nefropatia diabética (ND) é uma condição microvascular diabética prevalente. É a principal causa de doença renal em estágios avançados. Atualmente, não há tratamento eficaz disponível. Esta pesquisa teve como objetivo investigar os potenciais curativos de exossomos isolados de células-tronco mesenquimais que afetam a ND. Este estudo foi realizado em 70 ratos albinos adultos machos. Ratos adultos foram randomizados em sete grupos: Grupo I: Grupo de controle negativo, Grupo II: Grupo DN, Grupo III: Grupo tratado com Balanites, Grupo IV: Grupo tratado com MSCs, Grupo V: Grupo tratado com exossomos, Grupo VI: Grupo tratado com Balanites + MSCs e Grupo VII: Balanites + grupo tratado com exossomas. Após o período experimental, o sangue e os tecidos renais foram submetidos a análises bioquímicas, de expressão gênica e exames histopatológicos. Os resultados mostraram que o MDA aumentou substancialmente, enquanto o TAC diminuiu significativamente no rim no grupo DN em comparação com ratos saudáveis normais. Valores elevados indesejados de níveis de MDA e uma diminuição no TAC foram substancialmente melhorados em grupos coadministrados Balanites aegyptiacae com MSCs ou exossomas em comparação com o grupo DN. Uma elevação substancial em TNF-α e uma concentração substancialmente diminuída de IGF-1 foram observadas em ratos DN em comparação com ratos saudáveis normais. Em comparação com o grupo DN, a coadministração de Balanites aegyptiacae com MSCs ou exossomas melhorou substancialmente os valores elevados indesejáveis de TNF-α e IGF-1. Além disso, no grupo DN a expressão de mRNA de vanina-1, nefrina e colágeno IV foi significativamente maior do que em ratos saudáveis normais. Comparado com ratos DN, Vanin-1, Nephrin e colágeno IV Upregulation foram substancialmente reduzidos em grupos co-administrados Balanites aegyptiacae com MSCs ou exossomos. Em ratos DN, a expressão de AQP1 foi significativamente menor do que em ratos saudáveis normais. Além disso, os grupos que coadministraram Balanites aegyptiacae com MSCs ou exossomos demonstraram um aumento substancial na expressão de mRNA de AQP1 em comparação com ratos DN.

Uric Acid Reacts with Peroxidasin, Decreases Collagen IV Crosslink, Impairs Human Endothelial Cell Migration and Adhesion.

Uric acid is considered the main substrate for peroxidases in plasma. The oxidation of uric acid by human peroxidases generates urate free radical and urate hydroperoxide, which might affect endothelial function and explain, at least in part, the harmful effects of uric acid on the vascular system. Peroxidasin (PXDN), the most recent heme-peroxidase described in humans, catalyzes the formation of hypobromous acid, which mediates collagen IV crosslinks in the extracellular matrix. This enzyme has gained increasing scientific interest since it is associated with cardiovascular disease, cancer, and renal fibrosis. The main objective here was to investigate whether uric acid would react with PXDN and compromise the function of the enzyme in human endothelial cells. Urate decreased Amplex Red oxidation and brominating activity in the extracellular matrix (ECM) from HEK293/PXDN overexpressing cells and in the secretome of HUVECs. Parallelly, urate was oxidized to 5-hydroxyisourate. It also decreased collagen IV crosslink in isolated ECM from PFHR9 cells. Urate, the PXDN inhibitor phloroglucinol, and the PXDN knockdown impaired migration and adhesion of HUVECs. These results demonstrated that uric acid can affect extracellular matrix formation by competing for PXDN. The oxidation of uric acid by PXDN is likely a relevant mechanism in the endothelial dysfunction related to this metabolite.

Molecular characterization of collagen IV evidences early transcription expression related to the immune response against bacterial infection in the red abalone (Haliotis rufescens).

Collagen IV has been described as a structural protein of the basement membrane, which as a whole forms a specialized extracellular matrix. Recent studies have indicated a possible relationship between collagen IV and the innate immune response of invertebrate organisms. The present study characterized the alpha-1 chain of collagen IV in the red abalone Haliotis rufescens (Hr-ColIV) and evaluated its association with the innate immune response against Vibrio anguillarum. To further evidence the immune response, the matrix metalloproteinase-1 (Hr-MMP-1) and C-type lectin (Hr-CLEC) genes were also assessed. The complete sequence of Hr-ColIV was composed of 6658 bp, with a 5'UTR of 154 bp, a 3'UTR of 1177 bp, and an ORF of 5327 bp that coded for 1776 amino acids. The innate immune response generated against V. anguillarum resulted in a significant increase in the transcript levels of Hr-ColIV between 3 and 6 hpi, whereas Hr-MMP-1 and Hr-CLEC had the highest transcript activity 6 and 12 hpi, respectively. The results obtained in this study propose a putative biological function for collagen IV involved in the early innate immune response of the red abalone H. rufescens.