scholarly journals Actin dynamics at focal adhesions: a common endpoint and putative therapeutic target for proteinuric kidney diseases

2018 ◽  
Vol 93 (6) ◽  
pp. 1298-1307 ◽  
Author(s):  
Sanja Sever ◽  
Mario Schiffer
Keyword(s):  
Therapeutic Target ◽  
Kidney Diseases ◽  
Focal Adhesions ◽  
Actin Dynamics ◽  
Common Endpoint

Ectopic RASGRP2 (CalDAG-GEFI) expression in rheumatoid synovium contributes to the development of destructive arthritis

2018 ◽  
Vol 77 (12) ◽  
pp. 1765-1772 ◽  
Author(s):  
Hiroyuki Nakamura ◽  
Sanae Shimamura ◽  
Shinsuke Yasuda ◽  
Michihito Kono ◽  
Michihiro Kono ◽  
...  
Keyword(s):  
Transforming Growth Factor Beta ◽  
Therapeutic Target ◽  
Transforming Growth Factor ◽  
Remission Rate ◽  
Bone Destruction ◽  
Type Ii Collagen ◽  
Small Gtpase ◽  
Actin Dynamics ◽  
Migration And Invasion ◽  
Tissue Samples

ObjectivesRheumatoid arthritis (RA) is an autoimmune polyarthritis, in which fibroblast-like synoviocytes (FLS) play a key role in cartilage and bone destruction through tumour-like proliferation and invasiveness. Considering still unsatisfactory remission rate in RA even under treatment with biological disease-modifying antirheumatic drugs, novel therapeutic strategy for treatment-resistant RA is still awaited. In this study, we analysed the expression and function of Ras guanine nucleotide-releasing proteins (RASGRPs), guanine exchange factors for small GTPase Ras, in FLS as a potential therapeutic target for RA.MethodsThe expression of RASGRPs mRNA was quantified by a real-time PCR assay in FLS isolated from synovial tissue samples. RASGRP2 protein was also evaluated immunohistochemically. Then, we transiently transfected FLS with RASGRP2 expression vector and assessed their proliferation, adhesion, migration and invasion by cellular functional assays and downstream signalling activation using immunoblot. Finally, the therapeutic effect of RASGRP2 silencing was evaluated in type-II collagen-induced arthritis rats.ResultsRASGRP2 was abundantly expressed in FLS from RA synovium, whereas scarcely found in those from osteoarthritis. Expression of RASGRP2 in RA-FLS was enhanced by transforming growth factor-beta. RASGRP2 activated RAP-1, subsequently affecting nuclear factor kappa-light-chain-enhancer of activated B cells pathway and actin dynamics in FLS. RASGRP2-overexpressed FLS had increased abilities of adhesion, migration and interleukin (IL)-6 production. Silencing of RASGRP2 using the intra-articular injection of Rasgrp2-specific siRNAs dampened experimental arthritis in rats by inhibiting pannus formation.ConclusionsRASGRP2 was identified to be involved in the pathogenesis of RA by promoting adhesion, migration and IL-6 production from FLS, proposed as a potential novel non-immunosuppressive therapeutic target for RA.

scholarly journals Podocytes and the actin cytoskeleton as a feasible therapeutic target

2017 ◽  
Vol 118 (4) ◽  
Author(s):  
Sanja Sever ◽  
Changkyo Gu
Keyword(s):  
Animal Models ◽  
Actin Cytoskeleton ◽  
Therapeutic Target ◽  
Kidney Diseases ◽  
Glomerular Disease ◽  
Podocyte Injury ◽  
Chronic Kidney Diseases ◽  
Beneficial Effects ◽  
Actin Structure

Podocyte injury is a hallmark of the glomerular disease, which is a direct cause of chronic kidney diseases. Importantly, podocyte injury is a consequence of the dysregulation of the actin cytoskeleton. In diverse animal models of proteinuric glomerular disease, recovering the integrity of the actin structure in podocytes resulted in beneficial effects. In this review, we focus on the premise of targeting the actin cytoskeleton as a feasible therapeutics for treating chronic kidney diseases

scholarly journals Rab40/Cullin5 complex regulates EPLIN and actin cytoskeleton dynamics during cell migration and invasion

2021 ◽  
Author(s):  
Erik S Linklater ◽  
Emily Duncan ◽  
Ke Jun Han ◽  
Algirdas Kaupinis ◽  
Mindaugas Valius ◽  
...  
Keyword(s):  
Cell Migration ◽  
Actin Cytoskeleton ◽  
Focal Adhesion ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Stress Fibers ◽  
Actin Dynamics ◽  
Migration And Invasion ◽  
Matrix Remodeling ◽  
Cell Migration And Invasion

Rab40b is a SOCS box containing protein that regulates the secretion of MMPs to facilitate extracellular matrix remodeling during cell migration. Here we show that Rab40b interacts with Cullin5 via the Rab40b SOCS domain. We demonstrate that loss of Rab40b/Cullin5 binding decreases cell motility and invasive potential, and show that defective cell migration and invasion stem from alteration to the actin cytoskeleton, leading to decreased invadopodia formation, decreased actin dynamics at the leading edge, and an increase in stress fibers. We also show that these stress fibers anchor at less dynamic, more stable focal adhesions. Mechanistically, changes in the cytoskeleton and focal adhesion dynamics are mediated in part by EPLIN, which we demonstrate to be a binding partner of Rab40b and a target for Rab40b/Cullin5 dependent localized ubiquitylation and degradation. Thus, we propose a model where the Rab40b/Cullin5 dependent ubiquitylation regulates EPLIN localization to promote cell migration and invasion by altering focal adhesion and cytoskeletal dynamics.

scholarly journals Mesenchymal Stem Cells Ameliorate Interstitial Fibrosis in Adenine-induced Nephropathy Based on Renal Proteomics

2020 ◽  
Author(s):  
Huajun Tang ◽  
Peiyue Zhang ◽  
Lianlin Zeng ◽  
Yu Zhao ◽  
Libo Xie ◽  
...  
Keyword(s):  
Western Blot ◽  
Therapeutic Target ◽  
Bioinformatics Analysis ◽  
Interstitial Fibrosis ◽  
Kidney Diseases ◽  
Histopathological Change ◽  
Collagen Type I ◽  
Tubulointerstitial Fibrosis ◽  
Type I ◽  
Tgf Β1

Abstract Background: Tubulointerstitial fibrosis (TIF) is one of the main pathological features of various progressive renal damages and chronic kidney diseases. Mesenchymal stromal cells (MSCs) have been verified with significant improvement in the therapy of fibrosis diseases, but the mechanism is still unclear. We attempted to explore the new mechanism and therapeutic target of MSCs against renal fibrosis based on renal proteomics.Methods: TIF model was induced by adenine gavage. Bone marrow derived MSCs was injected by tail vein after modeling. Fibrosis biomarkers or extracellular matrix proteins and histopathological change were assessed by Masson staining, Sirius red staining, immunohistochemistry, and western blot. Renal proteomics was analyzed using iTRAQ-based mass spectrometry.Results: MSCs treatment clearly decreased the expression of α-SMA, collagen type I, II, III, TGF-β1, p-Smad2/3, IL-6, IL-1β, and TNFα compared with model rats, while p38 MAPK increased. 6,213 proteins were identified, but only 40 proteins exhibited significant differences (30 upregulated, 10 downregulated) compared MSCs group with the model group. Bioinformatics analysis revealed that these proteins play important roles in the proliferation, inflammatory and immune responses, apoptosis, phagosome, etc. According to literatures and bioinformatics analysis, the most markedly downregulated protein, galectin3, was further assessed by quantitative PCR and western blot in renal tissues. Galectin3 levels were downregulated in adenine-induced renal tissues and TGF-β1 induced tubular epithelial cells and interstitial fibroblasts in consistent with iTRAQ after MSCs treatment.Conclusion: The founds suggest that galectin3 maybe involves in the antifibrotic mechanisms of MSCs therapy for tubulointerstitial fibrosis as well as a possible therapeutic target.

scholarly journals WT1-interacting protein (Wtip) regulates podocyte phenotype by cell-cell and cell-matrix contact reorganization

2012 ◽  
Vol 302 (1) ◽  
pp. F103-F115 ◽  
Author(s):  
Jane H. Kim ◽  
Amitava Mukherjee ◽  
Sethu M. Madhavan ◽  
Martha Konieczkowski ◽  
John R. Sedor
Keyword(s):  
Kinase Inhibitor ◽  
Adherens Junctions ◽  
Focal Adhesions ◽  
Stress Fibers ◽  
Actin Dynamics ◽  
Transcriptional Responses ◽  
Interacting Protein ◽  
Cell Matrix ◽  
Actin Stress Fibers ◽  
Cell Cell

Podocytes respond to environmental cues by remodeling their slit diaphragms and cell-matrix adhesive junctions. Wt1-interacting protein (Wtip), an Ajuba family LIM domain scaffold protein expressed in the podocyte, coordinates cell adhesion changes and transcriptional responses to regulate podocyte phenotypic plasticity. We evaluated effects of Wtip on podocyte cell-cell and cell-matrix contact organization using gain-of- and loss-of-function methods. Endogenous Wtip targeted to focal adhesions in adherent but isolated podocytes and then shifted to adherens junctions after cells made stable, homotypic contacts. Podocytes with Wtip knockdown (shWtip) adhered but failed to spread normally. Noncontacted shWtip podocytes did not assemble actin stress fibers, and their focal adhesions failed to mature. As shWtip podocytes established cell-cell contacts, stable adherens junctions failed to form and F-actin structures were disordered. In shWtip cells, cadherin and β-catenin clustered in irregularly distributed spots that failed to laterally expand. Cell surface biotinylation showed diminished plasma membrane cadherin, β-catenin, and α-catenin in shWtip podocytes, although protein expression was similar in shWtip and control cells. Since normal actin dynamics are required for organization of adherens junctions and focal adhesions, we determined whether Wtip regulates F-actin assembly. Undifferentiated podocytes did not elaborate F-actin stress fibers, but when induced to overexpress WTIP, formed abundant stress fibers, a process blocked by the RhoA inhibitor C3 toxin and a RhoA kinase inhibitor. WTIP directly interacted with Rho guanine nucleotide exchange factor (GEF) 12 (Arhgef12), a RhoA-specific GEF enriched in the glomerulus. In conclusion, stable assembly of podocyte adherens junctions and cell-matrix contacts requires Wtip, a process that may be mediated by spatiotemporal regulation of RhoA activity through appropriate targeting of Arhgef12.

scholarly journals SOX9 is required for kidney fibrosis and regulates NAV3 to control renal myofibroblast function in mice and humans

2019 ◽  
Author(s):  
Sayyid Raza ◽  
Elliot Jokl ◽  
James Pritchett ◽  
Katherine Martin ◽  
Kim Su ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Kidney Diseases ◽  
Pharmacological Intervention ◽  
Chronic Kidney Diseases ◽  
Kidney Fibrosis ◽  
Genome Wide ◽  
Common Endpoint ◽  
Vitro Model ◽  
Novel Target

AbstractRenal fibrosis is a common endpoint for many chronic kidney diseases. Extracellular matrix (ECM) from myofibroblasts causes progressive scarring and organ failure. The mechanisms underlying fibrogenesis and how it is sustained are incompletely understood. Here, we show that the transcription factor, Sex determining region Y-box 9 (SOX9), is required for kidney fibrosis. From genome-wide analysis we identify Neuron navigator 3 (NAV3) downstream of SOX9. NAV3 was upregulated in kidney disease in patients and following renal injury in mice colocalised with SOX9. By establishing an in vitro model of renal pericyte transition to myofibroblast we demonstrated that NAV3 is required for multiple aspects of fibrogenesis including actin polymerization linked to cell migration and sustaining SOX9 and active YAP1 levels. In summary, our work discovers novel SOX9-NAV3-YAP1/SOX9 circuitry as a new mechanism to explain the progression of kidney fibrosis and points to NAV3 as a novel target for pharmacological intervention.

scholarly journals p130Cas contributes to cellular mechanosensing and force exertion

2018 ◽  
Author(s):  
Hedde van Hoorn ◽  
Dominique M. Donato ◽  
H. Emrah Balcioglu ◽  
Erik H. Danen ◽  
Thomas Schmidt
Keyword(s):  
Focal Adhesion ◽  
Adhesion Formation ◽  
Focal Adhesions ◽  
Full Length ◽  
Actin Dynamics ◽  
Knock Out ◽  
Focal Adhesion Formation ◽  
Pillar Arrays ◽  
Cellular Machinery ◽  
And Migration

AbstractCell survival, differentiation, and migration are all dependent on the cell’s interaction with its external environment. In addition to chemical cues, cells react to their physical environment, particularly the stiffness of the substrate. In order for cells to react to these elements, they must make use of cellular machinery to signal changes in their microenvironment. One such proposed machinery is the protein p130Cas, which has been shown to regulate focal adhesion turnover, actin dynamics, and cell migration. Here we show that p130Cas localizes to focal adhesions depending on substrate stiffness and subsequently modulates cellular force exertion. We compared on substrates of tunable stiffness knock-out CAS-/-cells to cells re-expressing either the full-length p130Cas or a mutant lacking the focal adhesion targeting domains. On polyacrylamide gels, we observed that p130Cas prevented focal adhesion formation at low stiffness. On structured micro-pillar arrays, p130Cas preferentially localized to sites of force exertion when the apparent Young’s modulus of the substrate was higher than E = 47 kPa. Stiffness-dependent localization of p130Cas coincided with slower, but increased force exertion for the full-length p130Cas. Cas localization to focal adhesions preceded force build-up by three minutes, suggesting a coordinating role for p130Cas in the cellular mechanoresponse. Thus, p130Cas appears to relay mechanosensory information in the cell through its ability to tune force exertion at the focal adhesion.

scholarly journals Arf•GAPs as Regulators of the Actin Cytoskeleton—An Update

2019 ◽  
Vol 20 (2) ◽  
pp. 442 ◽  
Author(s):  
Christine Tanna ◽  
Louisa Goss ◽  
Calvin Ludwig ◽  
Pei-Wen Chen
Keyword(s):  
Protein Interactions ◽  
Cell Function ◽  
Critical Role ◽  
Focal Adhesions ◽  
Actin Dynamics ◽  
Protein Protein Interactions ◽  
Post Translational Modification ◽  
Cellular Functions ◽  
Binding Domains ◽  
Multiple Protein

Arf•GTPase-activating proteins (Arf•GAPs) control the activity of ADP-ribosylation factors (Arfs) by inducing GTP hydrolysis and participate in a diverse array of cellular functions both through mechanisms that are dependent on and independent of their Arf•GAP activity. A number of these functions hinge on the remodeling of actin filaments. Accordingly, some of the effects exerted by Arf•GAPs involve proteins known to engage in regulation of the actin dynamics and architecture, such as Rho family proteins and nonmuscle myosin 2. Circular dorsal ruffles (CDRs), podosomes, invadopodia, lamellipodia, stress fibers and focal adhesions are among the actin-based structures regulated by Arf•GAPs. Arf•GAPs are thus important actors in broad functions like adhesion and motility, as well as the specialized functions of bone resorption, neurite outgrowth, and pathogen internalization by immune cells. Arf•GAPs, with their multiple protein-protein interactions, membrane-binding domains and sites for post-translational modification, are good candidates for linking the changes in actin to the membrane. The findings discussed depict a family of proteins with a critical role in regulating actin dynamics to enable proper cell function.

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