Search results for "RAC1"
showing 10 items of 36 documents
β-Lactoglobulin Heptapeptide Reduces Oxidative Stress in Intestinal Epithelial Cells and Angiotensin II-Induced Vasoconstriction on Mouse Mesenteric …
2019
Peptides derived from buffalo dairy products possess multiple healthy properties that cannot be exerted as long as they are encrypted in parent proteins. To evaluate the biological activities of encrypted peptide sequences from buffalo ricotta cheese, we performed a simulated gastrointestinal (GI) digestion. Chemical and pharmacological characterization of the digest led to the identification of a novel peptide endowed with antioxidant and antihypertensive action. The GI digest was fractionated by Semiprep-HPLC, and fractions were tested against reactive oxygen species (ROS) release in an H2O2-treated intestinal epithelial cell line. UHPLC-PDA-MS/MS analysis revealed the presence of an abun…
Pattern of Invasion in Human Pancreatic Cancer Organoids Is Associated with Loss of SMAD4 and Clinical Outcome
2020
Abstract Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by extensive local invasion and systemic spread. In this study, we employed a three-dimensional organoid model of human pancreatic cancer to characterize the molecular alterations critical for invasion. Time-lapse microscopy was used to observe invasion in organoids from 25 surgically resected human PDAC samples in collagen I. Subsequent lentiviral modification and small-molecule inhibitors were used to investigate the molecular programs underlying invasion in PDAC organoids. When cultured in collagen I, PDAC organoids exhibited two distinct, morphologically defined invasive phenotypes, mesenchymal an…
Modulating Neuronal Competition Dynamics in the Dentate Gyrus to Rejuvenate Aging Memory Circuits.
2015
The neural circuit mechanisms underlying the integration and functions of adult-born dentate granule cell (DGCs) are poorly understood. Adult-born DGCs are thought to compete with mature DGCs for inputs to integrate. Transient genetic overexpression of a negative regulator of dendritic spines, Kruppel-like factor 9 (Klf9), in mature DGCs enhanced integration of adult-born DGCs and increased NSC activation. Reversal of Klf9 overexpression in mature DGCs restored spines and activity and reset neuronal competition dynamics and NSC activation, leaving the DG modified by a functionally integrated, expanded cohort of age-matched adult-born DGCs. Spine elimination by inducible deletion of Rac1 in …
Designer Thiopurine-analogues for Optimised Immunosuppression in Inflammatory Bowel Diseases.
2015
Background and Aims: The clinical use of azathioprine and 6-mercaptopurine is limited by their delayed onset of action and potential side effects such as myelosuppression and hepatotoxicity. As these drugs specifically target the Vav1/Rac1 signalling pathway in T lamina propria lymphocytes via their metabolite 6-thio-GTP, we studied expression and optimised suppression of this pathway in inflammatory bowel diseases [IBD]. Methods: Rac1 and Vav1 expressions were analysed in mucosal immune cells in IBD patients. Targeted molecular modelling of the 6-thio-GTP molecule was performed to optimise Rac1 blockade; 44 modified designer thiopurine-analogues were tested for apoptosis induction, potenti…
CD28-dependent Rac1 activation is the molecular target of azathioprine in primary human CD4+ T lymphocytes
2003
Azathioprine and its metabolite 6-mercaptopurine (6-MP) are immunosuppressive drugs that are used in organ transplantation and autoimmune and chronic inflammatory diseases such as Crohn disease. However, their molecular mechanism of action is unknown. In the present study, we have identified a unique and unexpected role for azathioprine and its metabolites in the control of T cell apoptosis by modulation of Rac1 activation upon CD28 costimulation. We found that azathioprine and its metabolites induced apoptosis of T cells from patients with Crohn disease and control patients. Apoptosis induction required costimulation with CD28 and was mediated by specific block- ade of Rac1 activation thro…
Azathioprine suppresses ezrin-radixin-moesin-dependent T cell-APC conjugation through inhibition of Vav guanosine exchange activity on rac proteins
2006
Abstract We have shown recently that the azathioprine metabolite 6-Thio-GTP causes immunosuppression by blockade of GTPase activation in T lymphocytes. In the present study, we describe a new molecular mechanism by which 6-Thio-GTP blocks GTPase activation. Although 6-Thio-GTP could bind to various small GTPases, it specifically blocked activation of Rac1 and Rac2 but not of closely related Rho family members such as Cdc42 and RhoA in primary T cells upon stimulation with αCD28 or fibronectin. Binding of 6-Thio-GTP to Rac1 did not suppress Rac effector coupling directly but blocked Vav1 exchange activity upon 6-Thio-GTP hydrolysis, suggesting that 6-Thio-GTP loading leads to accumulation of…
Urine cadmium levels and albuminuria in a general population from Spain: A gene-environment interaction analysis
2017
Background: The interaction of cadmium with genes involved in oxidative stress, cadmium metabolism and transport pathways on albuminuria can provide biological insight on the relationship between cadmium and albuminuria at low exposure levels. Objectives: We tested the hypothesis that specific genotypes in candidate genes may confer increased susceptibility to cadmium exposure. Methods: Cadmium exposure was estimated by inductively coupled plasma mass spectrometry (ICPMS) in urine from 1397 men and women aged 18–85years participating in the Hortega Study, a representative sample of a general population from Spain. Urine albumin was measured by automated nephelometric immunochemistry. Abnorm…
The lipoprotein receptor LRP1 modulates sphingosine-1-phosphate signaling and is essential for vascular development
2014
Low density lipoprotein receptor-related protein 1 (LRP1) is indispensable for embryonic development. Comparing different genetically engineered mouse models, we found that expression of Lrp1 is essential in the embryo proper. Loss of LRP1 leads to lethal vascular defects with lack of proper investment with mural cells of both large and small vessels. We further demonstrate that LRP1 modulates Gi-dependent sphingosine-1-phosphate (S1P) signaling and integrates S1P and PDGF-BB signaling pathways, which are both crucial for mural cell recruitment, via its intracellular domain. Loss of LRP1 leads to a lack of S1P-dependent inhibition of RAC1 and loss of constraint of PDGF-BB-induced cell migra…
Abstract 3940: Inactivation of the PARD3 gene is a recurrent event in lung squamous cell carcinomas and affects STAT3 activity and tumor invasiveness
2015
Abstract Correct apicobasal polarization and intercellular adhesions are essential for the appropriate development of normal epithelia. Here, we investigated the contribution of the partitioning defective 3 gene, PARD3, to the carcinogenesis of lung squamous cell carcinomas (LSCCs). Tumor-specific PARD3 alterations were found in eight per cent of the tumors, placing PARD3 among the most common tumor suppressor genes in LSCC. Some PAR3 mutant proteins prevented the formation of contacts between neighboring cells, i.e. had reduced ability to form tight junctions and actin-based protrusions. This affected subsequent downstream signaling, i.e. binding to aPKC and activation of RAC1. Further, we…
APE/Ref-1 and the mammalian response to genotoxic stress.
2003
Human apurinic/apyrimidinic endonuclease/redox factor-1 (hAPE/Ref-1) is a multifunctional protein involved in the repair of DNA damaged by oxidative or alkylating compounds as well as in the regulation of stress inducible transcription factors such as AP-1, NF-kappaB, HIF-1 and p53. With respect to transcriptional regulation, both redox dependent and independent mechanisms have been described. APE/Ref-1 also acts as a transcriptional repressor. Recent data indicate that APE/Ref-1 negatively regulates the activity of the Ras-related GTPase Rac1. How these different physiological activities of APE/Ref-1 are coordinated is poorly understood. So far, convincing evidence is available that the ex…