scholarly journals Loss of filtration function in diabetic glomeruli is associated with ultrastructural changes in glomerular endothelial cell fenestrations

2020 ◽  
Author(s):  
Natalie Finch ◽  
Sarah Fawaz ◽  
Chris Neal ◽  
Matthew Butler ◽  
Vivian Lee ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Endothelial Cell ◽  
Glomerular Filtration ◽  
Critical Role ◽  
Ultrastructural Changes ◽  
Glomerular Endothelial Cell ◽  
Functional Changes ◽  
Glomerular Ultrafiltration

Background: The study of glomerular endothelial cell (GEnC) fenestrations including key regulatory factors is neglected despite their loss in diabetic nephropathy, a disease associated with decreased filtration function, being previously described. Methods: We comprehensively characterised GEnC fenestral and renal filtration functional changes including measurement of glomerular ultrafiltration coefficient and glomerular filtration rate (GFR) in diabetic mice and humans. We further evaluated Eps homology domain protein-3 (Ehd3) as a potential regulator of GEnC fenestrations. Results: This study identified loss of GEnC fenestration density which was associated with decreased renal filtration function in diabetic nephropathy. We also identified increased GEnC fenestration width, an ultrastructural change that may develop to maintain filtration surface area. GEnC fenestration width was negatively associated with renal filtration function considered a result of development of diaphragms in widening fenestrations providing resistance to filtration. The increased presence of diaphragmed fenestrations in diabetes was supported by increased PLVAP1 expression. We identified decreased glomerular Ehd3 expression in diabetes and demonstrated its association with GEnC fenestration measurements suggesting its role in regulating fenestrations. We further demonstrated reduced fenestration formation in vitro in an Ehd3 knockdown cell line. Ehd3 was positively associated with filtration function suggesting loss of glomerular Ehd3 expression in disease may contribute to declining glomerular filtration function through aberrant GEnC fenestration regulation. Conclusions: This is the first study to demonstrate the critical role of GEnC fenestrations in renal filtration function and identify a key regulator, Ehd3, that may serve as a therapeutic target to retore filtration function in disease.

scholarly journals Glomerular endothelial cell fenestrations: an integral component of the glomerular filtration barrier

2009 ◽  
Vol 296 (5) ◽  
pp. F947-F956 ◽  
Author(s):  
Simon C. Satchell ◽  
Filip Braet
Keyword(s):  
Endothelial Cell ◽  
Glomerular Filtration ◽  
In Vitro Models ◽  
Glomerular Injury ◽  
Glomerular Endothelial Cell ◽  
Glomerular Filtration Barrier ◽  
Therapeutic Implications ◽  
Filtration Barrier ◽  
Glomerular Development

Glomerular endothelial cell (GEnC) fenestrations are analogous to podocyte filtration slits, but their important contribution to the glomerular filtration barrier has not received corresponding attention. GEnC fenestrations are transcytoplasmic holes, specialized for their unique role as a prerequisite for filtration across the glomerular capillary wall. Glomerular filtration rate is dependent on the fractional area of the fenestrations and, through the glycocalyx they contain, GEnC fenestrations are important in restriction of protein passage. Hence, dysregulation of GEnC fenestrations may be associated with both renal failure and proteinuria, and the pathophysiological importance of GEnC fenestrations is well characterized in conditions such as preeclampsia. Recent evidence suggests a wider significance in repair of glomerular injury and in common, yet serious, conditions, including diabetic nephropathy. Study of endothelial cell fenestrations is challenging because of limited availability of suitable in vitro models and by the requirement for electron microscopy to image these sub-100-nm structures. However, extensive evidence, from glomerular development in rodents to in vitro studies in human GEnC, points to vascular endothelial growth factor (VEGF) as a key inducer of fenestrations. In systemic endothelial fenestrations, the intracellular pathways through which VEGF acts to induce fenestrations include a key role for the fenestral diaphragm protein plasmalemmal vesicle-associated protein-1 (PV-1). The role of PV-1 in GEnC is less clear, not least because of controversy over existence of GEnC fenestral diaphragms. In this article, the structure-function relationships of GEnC fenestrations will be evaluated in depth, their role in health and disease explored, and the outlook for future study and therapeutic implications of these peculiar structures will be approached.

scholarly journals Emergent role of SARAF and store-operated Ca2+ entry in angiogenesis

2021 ◽  
Vol 154 (9) ◽  
Author(s):  
Isabel María Galeano-Otero ◽  
Raquel Del Toro ◽  
Tarik Smani
Keyword(s):  
Endothelial Cell ◽  
Ex Vivo ◽  
Critical Role ◽  
Basal Medium ◽  
Aortic Ring ◽  
Tube Formation ◽  
Multistep Process ◽  
And Migration

Angiogenesis is a multistep process that controls endothelial cell (EC) functioning to form new blood vessels from preexisting vascular beds. This process is tightly regulated by pro-angiogenic factors, such as vascular endothelial growth factor (VEGF), which promotes signaling pathways involving the increase in the intracellular Ca2+ concentration ([Ca2+]i). Recent evidence suggests that store-operated Ca2+ entry (SOCE) might play a role in angiogenesis. However, little is known regarding the role of SARAF, SOCE-associated regulatory factor in this process. The aim of this study is to examine the role of SARAF in angiogenesis. In vitro angiogenesis was studied using human umbilical endothelial cells (HUVECs) for tube formation assay and vessel sprouting using rat aortic ring by Matrigel assay supplemented with endothelial cell basal medium enriched with different growth factors (VEGF, FGF, b-EGF, and IGF). HUVECs migration was evaluated by wound healing assay, and HUVECs proliferation using Ki67+ marker. Ex vivo angiogenesis was examined by whole mount mice retina on P6 in neonatal mice injected with increasing concentrations of a SOCE inhibitor, GSK-7975A, on P3, P4, and P5. We observed that SOCE inhibition with GSK-7975A blocks aorta sprouting, as well as HUVEC tube formation and migration. The intraperitoneal injection of GSK-7975A also delays the development of retinal vasculature assessed at postnatal day 6 in mice since it reduces vessel length and the number of junctions while it increases lacunarity. Moreover, we found that knockdown of SARAF using siRNA impairs VEGF-mediated [Ca2+]i increase and HUVEC tube formation, proliferation, and migration. Our data show for the first that SOCE inhibition prevents angiogenesis using different approaches and we provide evidence indicating that SARAF plays a critical role in angiogenesis.

Endothelial cell monolayers as a tool for studying microvascular pathophysiology

1997 ◽  
Vol 273 (6) ◽  
pp. G1189-G1199 ◽  
Author(s):  
Peter R. Kvietys ◽  
D. Neil Granger
Keyword(s):  
Endothelial Cell ◽  
In Vitro Model ◽  
Cultured Cells ◽  
Critical Role ◽  
In Vitro Models ◽  
Cell Monolayers ◽  
Biological Responses ◽  
Vitro Model

Endothelial cells contribute to a variety of biological responses that facilitate organ function. This critical role of the endothelial cell has resulted in the development of different in vitro models that utilize monolayers of cultured cells to simulate conditions that exist in the intact animal. This review focuses on endothelial cell monolayers as a model system for research on certain pathophysiological conditions affecting the gastrointestinal tract. The advantages and limitations of endothelial cell monolayers are addressed, along with evolving technologies and strategies that hold promise for extending the utility of this in vitro model for studies of gastrointestinal function and disease.

scholarly journals Endothelial reticulon-4B (Nogo-B) regulates ICAM-1–mediated leukocyte transmigration and acute inflammation

Blood ◽  
2011 ◽  
Vol 117 (7) ◽  
pp. 2284-2295 ◽  
Author(s):  
Annarita Di Lorenzo ◽  
Thomas D. Manes ◽  
Alberto Davalos ◽  
Paulette L. Wright ◽  
William C. Sessa
Keyword(s):  
Bone Marrow ◽  
Endothelial Cell ◽  
Critical Role ◽  
Vascular Endothelial Cell ◽  
Intercellular Adhesion Molecule ◽  
Immune Functions ◽  
Intercellular Adhesion Molecule 1 ◽  
Leukocyte Transmigration

Abstract The reticulon (Rtn) family of proteins are localized primarily to the endoplasmic reticulum (ER) of most cells. The Rtn-4 family, (aka Nogo) consists of 3 splice variants of a common gene called Rtn-4A, Rtn-4B, and Rtn-4C. Recently, we identified the Rtn-4B (Nogo-B) protein in endothelial and smooth muscle cells of the vessel wall, and showed that Nogo-B is a regulator of cell migration in vitro and vascular remodeling and angiogenesis in vivo. However, the role of Nogo-B in inflammation is still largely unknown. In the present study, we use 2 models of inflammation to show that endothelial Nogo-B regulates leukocyte transmigration and intercellular adhesion molecule-1 (ICAM-1)–dependent signaling. Mice lacking Nogo-A/B have a marked reduction in neutrophil and monocyte recruitment to sites of inflammation, while Nogo-A/B−/− mice engrafted with wild-type (WT) bone marrow still exhibit impaired inflammation compared with WT mice engrafted with Nogo-A/B−/− bone marrow, arguing for a critical role of host Nogo in this response. Using human leukocytes and endothelial cells, we show mechanistically that the silencing of Nogo-B with small interfering RNA (siRNA) impairs the transmigration of neutrophils and reduces ICAM-1–stimulated phosphorylation of vascular endothelial-cell cadherin (VE-cadherin). Our results reveal a novel role of endothelial Nogo-B in basic immune functions and provide a key link in the molecular network governing endothelial-cell regulation of diapedesis.

scholarly journals Salvianolic Acid A Protects Against Diabetic Nephropathy through Ameliorating Glomerular Endothelial Dysfunction via Inhibiting AGE-RAGE Signaling

2017 ◽  
Vol 44 (6) ◽  
pp. 2378-2394 ◽  
Author(s):  
Biyu Hou ◽  
Guifen Qiang ◽  
Yuerong Zhao ◽  
Xiuying Yang ◽  
Xi Chen ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Endothelial Cell ◽  
Early Stage ◽  
Cell Permeability ◽  
Glomerular Endothelial Cell ◽  
Salvianolic Acid ◽  
Structural Deterioration ◽  
Salvianolic Acid A

Background/Aims: Glomerular endothelium dysfunction leads to the progression of renal architectonic and functional abnormalities in early-stage diabetic nephropathy (DN). Advanced glycation end products (AGEs) and receptor for AGEs (RAGE) are proved to play important roles in diabetic nephropathy. This study investigated the role of Salvianolic acid A (SalA) on early-stage DN and its possible underlying mechanism. Methods: In vitro AGEs formation and breaking rate were measured to illustrate the effect of SalA on AGEs. Type 2 diabetic nephropathy rats were induced by high-fat diet and low-dose streptozocin (STZ). After eight-week treatment with SalA 1 mg/kg/day, 24h-urine protein, creatinine clearance was tested and renal structural injury was assessed by PAS and PASM staining. Primary glomerular endothelial cell permeability was evaluated after exposed to AGEs. AGEs-induced RhoA/ROCK and subsequently activated disarrange of cytoskeleton were assessed by western blot and immunofluorescence. Results: Biochemical assay and histological examination demonstrated that SalA markedly reduced endothelium loss and glomerular hyperfiltration, suppressed glomerular hypertrophy and mesangial matrix expansion, eventually reduced urinary albumin and ameliorated renal function. Further investigation suggested that SalA exerted its renoprotective effects through inhibiting AGE-RAGE signaling. It not only inhibited formation of AGEs and increased its breaking in vitro, but also reduced AGEs accumulation in vivo and downregulated RAGE expression. SalA restored glomerular endothelial permeability through suppressing AGEs-induced rearrangement of actin cytoskeleton via AGE-RAGE-RhoA/ ROCK pathway. Moreover, SalA attenuated oxidative stress induced by AGEs, subsequently alleviated inflammation and restored the disturbed autophagy in glomerular endothelial cell and diabetic rats via AGE-RAGE-Nox4 axis. Conclusion: Our study indicated that SalA restored glomerular endothelial function and alleviated renal structural deterioration through inhibiting AGE-RAGE, thus effectively ameliorated early-stage diabetic nephropathy. SalA might be a promising therapeutic agent for the treatment of diabetic nephropathy.

scholarly journals The role of anti-endothelial cell antibodies in Kawasaki disease -in vitro and in vivo studies

2002 ◽  
Vol 130 (2) ◽  
pp. 233-240 ◽  
Author(s):  
E. GRUNEBAUM ◽  
M. BLANK ◽  
S. COHEN ◽  
A. AFEK ◽  
J. KOPOLOVIC ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Kawasaki Disease ◽  
In Vivo Studies

scholarly journals NLRP7 Promotes Choriocarcinoma Growth and Progression through the Establishment of an Immunosuppressive Microenvironment

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2999
Author(s):  
Deborah Reynaud ◽  
Roland Abi Nahed ◽  
Nicolas Lemaitre ◽  
Pierre-Adrien Bolze ◽  
Wael Traboulsi ◽  
...  
Keyword(s):  
Immune Response ◽  
Tumor Cells ◽  
Major Gene ◽  
Critical Role ◽  
Orthotopic Model ◽  
Independent Manner ◽  
Maternal Immune Response ◽  
The Impact

The inflammatory gene NLRP7 is the major gene responsible for recurrent complete hydatidiform moles (CHM), an abnormal pregnancy that can develop into gestational choriocarcinoma (CC). However, the role of NLRP7 in the development and immune tolerance of CC has not been investigated. Three approaches were employed to define the role of NLRP7 in CC development: (i) a clinical study that analyzed human placenta and sera collected from women with normal pregnancies, CHM or CC; (ii) an in vitro study that investigated the impact of NLRP7 knockdown on tumor growth and organization; and (iii) an in vivo study that used two CC mouse models, including an orthotopic model. NLRP7 and circulating inflammatory cytokines were upregulated in tumor cells and in CHM and CC. In tumor cells, NLRP7 functions in an inflammasome-independent manner and promoted their proliferation and 3D organization. Gravid mice placentas injected with CC cells invalidated for NLRP7, exhibited higher maternal immune response, developed smaller tumors, and displayed less metastases. Our data characterized the critical role of NLRP7 in CC and provided evidence of its contribution to the development of an immunosuppressive maternal microenvironment that not only downregulates the maternal immune response but also fosters the growth and progression of CC.

scholarly journals The role of the PZP domain of AF10 in acute leukemia driven by AF10 translocations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Brianna J. Klein ◽  
Anagha Deshpande ◽  
Khan L. Cox ◽  
Fan Xuan ◽  
Mohamad Zandian ◽  
...  
Keyword(s):  
Critical Role ◽  
Cellular Transformation ◽  
Acute Leukemias ◽  
Hematopoietic Stem ◽  
Nucleosome Core ◽  
Stem And Progenitor Cells ◽  
Transforming Activity

AbstractChromosomal translocations of the AF10 (or MLLT10) gene are frequently found in acute leukemias. Here, we show that the PZP domain of AF10 (AF10PZP), which is consistently impaired or deleted in leukemogenic AF10 translocations, plays a critical role in blocking malignant transformation. Incorporation of functional AF10PZP into the leukemogenic CALM-AF10 fusion prevents the transforming activity of the fusion in bone marrow-derived hematopoietic stem and progenitor cells in vitro and in vivo and abrogates CALM-AF10-mediated leukemogenesis in vivo. Crystallographic, biochemical and mutagenesis studies reveal that AF10PZP binds to the nucleosome core particle through multivalent contacts with the histone H3 tail and DNA and associates with chromatin in cells, colocalizing with active methylation marks and discriminating against the repressive H3K27me3 mark. AF10PZP promotes nuclear localization of CALM-AF10 and is required for association with chromatin. Our data indicate that the disruption of AF10PZP function in the CALM-AF10 fusion directly leads to transformation, whereas the inclusion of AF10PZP downregulates Hoxa genes and reverses cellular transformation. Our findings highlight the molecular mechanism by which AF10 targets chromatin and suggest a model for the AF10PZP-dependent CALM-AF10-mediated leukemogenesis.

scholarly journals The Inflammatory Role of Pro-Resolving Mediators in Endometriosis: An Integrative Review

2021 ◽  
Vol 22 (9) ◽  
pp. 4370
Author(s):  
Cássia de Fáveri ◽  
Paula M. Poeta Fermino ◽  
Anna P. Piovezan ◽  
Lia K. Volpato
Keyword(s):  
Intracellular Signaling ◽  
Inflammatory Responses ◽  
Therapeutic Potential ◽  
Critical Role ◽  
Integrative Review ◽  
Inflammatory Factors ◽  
Resolvin D1 ◽  
Endogenous Factors

The pathogenesis of endometriosis is still controversial, although it is known that the inflammatory immune response plays a critical role in this process. The resolution of inflammation is an active process where the activation of endogenous factors allows the host tissue to maintain homeostasis. The mechanisms by which pro-resolving mediators (PRM) act in endometriosis are still little explored. Thus, this integrative review aims to synthesize the available content regarding the role of PRM in endometriosis. Experimental and in vitro studies with Lipoxin A4 demonstrate a potential inhibitory effect on endometrial lesions’ progression, attenuating pro-inflammatory and angiogenic signals, inhibiting proliferative and invasive action suppressing intracellular signaling induced by cytokines and estradiol, mainly through the FPR2/ALX. Investigations with Resolvin D1 demonstrated the inhibition of endometrial lesions and decreased pro-inflammatory factors. Annexin A1 is expressed in the endometrium and is specifically present in women with endometriosis, although the available studies are still inconsistent. Thus, we believe there is a gap in knowledge regarding the PRM pathways in patients with endometriosis. It is important to note that these substances’ therapeutic potential is evident since the immune and abnormal inflammatory responses play an essential role in endometriosis development and progression.

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