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Balashova OA, Panoutsopoulos AA, Visina O, Selhub J, Knoepfler PS, Borodinsky LN. Noncanonical function of folate through folate receptor 1 during neural tube formation. Nat Commun 2024; 15:1642. [PMID: 38388461 PMCID: PMC10883926 DOI: 10.1038/s41467-024-45775-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/02/2024] [Indexed: 02/24/2024] Open
Abstract
Folate supplementation reduces the occurrence of neural tube defects (NTDs), birth defects consisting in the failure of the neural tube to form and close. The mechanisms underlying NTDs and their prevention by folate remain unclear. Here we show that folate receptor 1 (FOLR1) is necessary for the formation of neural tube-like structures in human-cell derived neural organoids. FOLR1 knockdown in neural organoids and in Xenopus laevis embryos leads to NTDs that are rescued by pteroate, a folate precursor that is unable to participate in metabolism. We demonstrate that FOLR1 interacts with and opposes the function of CD2-associated protein, molecule essential for apical endocytosis and turnover of C-cadherin in neural plate cells. In addition, folates increase Ca2+ transient frequency, suggesting that folate and FOLR1 signal intracellularly to regulate neural plate folding. This study identifies a mechanism of action of folate distinct from its vitamin function during neural tube formation.
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Affiliation(s)
- Olga A Balashova
- Department of Physiology & Membrane Biology, Shriners Hospitals for Children Northern California, University of California Davis, School of Medicine, Sacramento, CA, 95817, USA.
| | - Alexios A Panoutsopoulos
- Department of Physiology & Membrane Biology, Shriners Hospitals for Children Northern California, University of California Davis, School of Medicine, Sacramento, CA, 95817, USA
| | - Olesya Visina
- Department of Physiology & Membrane Biology, Shriners Hospitals for Children Northern California, University of California Davis, School of Medicine, Sacramento, CA, 95817, USA
| | - Jacob Selhub
- Tufts-USDA Human Nutrition Research Center on Aging, Boston, MA, USA
| | - Paul S Knoepfler
- Department of Cell Biology & Human Anatomy, Shriners Hospitals for Children Northern California, University of California Davis, School of Medicine, Sacramento, CA, 95817, USA
| | - Laura N Borodinsky
- Department of Physiology & Membrane Biology, Shriners Hospitals for Children Northern California, University of California Davis, School of Medicine, Sacramento, CA, 95817, USA.
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Balashova OA, Panoutsopoulos AA, Visina O, Selhub J, Knoepfler PS, Borodinsky LN. Non-canonical function of folate/folate receptor 1 during neural tube formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.19.549718. [PMID: 37503108 PMCID: PMC10370062 DOI: 10.1101/2023.07.19.549718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Folate supplementation reduces the occurrence of neural tube defects, one of the most common and serious birth defects, consisting in the failure of the neural tube to form and close early in pregnancy. The mechanisms underlying neural tube defects and folate action during neural tube formation remain unclear. Here we show that folate receptor 1 (FOLR1) is necessary for the formation of neural tube-like structures in human-cell derived neural organoids. Knockdown of FOLR1 in human neural organoids as well as in the Xenopus laevis in vivo model leads to neural tube defects that are rescued by pteroate, a folate precursor that binds to FOLR1 but is unable to participate in metabolic pathways. We demonstrate that FOLR1 interacts with and opposes the function of CD2-associated protein (CD2AP), a molecule that we find is essential for apical endocytosis and the spatiotemporal turnover of the cell adherens junction component C-cadherin in neural plate cells. The counteracting action of FOLR1 on these processes is mediated by regulating CD2AP protein level via a degradation-dependent mechanism. In addition, folate and pteroate increase Ca 2+ transient frequency in the neural plate in a FOLR1-dependent manner, suggesting that folate/FOLR1 signal intracellularly to regulate neural plate folding. This study identifies a mechanism of action of folate distinct from its vitamin function during neural tube formation.
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Liu P, Zhang J, Wang Y, Wang C, Qiu X, Chen DQ. Natural Products Against Renal Fibrosis via Modulation of SUMOylation. Front Pharmacol 2022; 13:800810. [PMID: 35308200 PMCID: PMC8931477 DOI: 10.3389/fphar.2022.800810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 02/08/2022] [Indexed: 12/29/2022] Open
Abstract
Renal fibrosis is the common and final pathological process of kidney diseases. As a dynamic and reversible post-translational modification, SUMOylation and deSUMOylation of transcriptional factors and key mediators significantly affect the development of renal fibrosis. Recent advances suggest that SUMOylation functions as the promising intervening target against renal fibrosis, and natural products prevent renal fibrosis via modulating SUMOylation. Here, we introduce the mechanism of SUMOylation in renal fibrosis and therapeutic effects of natural products. This process starts by summarizing the key mediators and enzymes during SUMOylation and deSUMOylation and its regulation role in transcriptional factors and key mediators in renal fibrosis, then linking the mechanism findings of SUMOylation and natural products to develop novel therapeutic candidates for treating renal fibrosis, and concludes by commenting on promising therapeutic targets and candidate natural products in renal fibrosis via modulating SUMOylation, which highlights modulating SUMOylation as a promising strategy for natural products against renal fibrosis.
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Affiliation(s)
- Peng Liu
- Shunyi Hospital, Beijing Hospital of Traditional Chinese Medicine, Beijing, China
| | - Jing Zhang
- Institute of Plant Resources, Yunnan University, Kunming, China
| | - Yun Wang
- Shunyi Hospital, Beijing Hospital of Traditional Chinese Medicine, Beijing, China
| | - Chen Wang
- Shunyi Hospital, Beijing Hospital of Traditional Chinese Medicine, Beijing, China
| | - Xinping Qiu
- Shunyi Hospital, Beijing Hospital of Traditional Chinese Medicine, Beijing, China
| | - Dan-Qian Chen
- Department of Emergency, China-Japan Friendship Hospital, Beijing, China
- *Correspondence: Dan-Qian Chen,
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Kong MS, Hashimoto-Tane A, Kawashima Y, Sakuma M, Yokosuka T, Kometani K, Onishi R, Carpino N, Ohara O, Kurosaki T, Phua KK, Saito T. Inhibition of T cell activation and function by the adaptor protein CIN85. Sci Signal 2019; 12:12/567/eaav4373. [PMID: 30723173 DOI: 10.1126/scisignal.aav4373] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
T cell activation is initiated by signaling molecules downstream of the T cell receptor (TCR) that are organized by adaptor proteins. CIN85 (Cbl-interacting protein of 85 kDa) is one such adaptor protein. Here, we showed that CIN85 limited T cell responses to TCR stimulation. Compared to activated wild-type (WT) T cells, those that lacked CIN85 produced more IL-2 and exhibited greater proliferation. After stimulation of WT T cells with their cognate antigen, CIN85 was recruited to the TCR signaling complex. Early TCR signaling events, such as phosphorylation of ζ-chain-associated protein kinase 70 (Zap70), Src homology 2 (SH2) domain-containing leukocyte protein of 76 kDa (SLP76), and extracellular signal-regulated kinase (Erk), were enhanced in CIN85-deficient T cells. The inhibitory function of CIN85 required the SH3 and PR regions of the adaptor, which associated with the phosphatase suppressor of TCR signaling-2 (Sts-2) after TCR stimulation. Together, our data suggest that CIN85 is recruited to the TCR signaling complex and mediates inhibition of T cell activation through its association with Sts-2.
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Affiliation(s)
- Mei Suen Kong
- Laboratory for Cell Signaling, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan.,Institute for Research in Molecular Medicine, Main Campus, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia
| | - Akiko Hashimoto-Tane
- Laboratory for Cell Signaling, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Kawashima
- Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan.,Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan
| | - Machie Sakuma
- Laboratory for Cell Signaling, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Tadashi Yokosuka
- Laboratory for Cell Signaling, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Kohei Kometani
- Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Reiko Onishi
- Laboratory for Cell Signaling, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Nick Carpino
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-8434, USA
| | - Osamu Ohara
- Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan.,Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan.,Lymphocyte Differentiation, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kia Kien Phua
- Institute for Research in Molecular Medicine, Main Campus, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia
| | - Takashi Saito
- Laboratory for Cell Signaling, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan. .,Cell Signaling, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
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Novosylna O, Doyle A, Vlasenko D, Murphy M, Negrutskii B, El'skaya A. Comparison of the ability of mammalian eEF1A1 and its oncogenic variant eEF1A2 to interact with actin and calmodulin. Biol Chem 2017; 398:113-124. [PMID: 27483363 DOI: 10.1515/hsz-2016-0172] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/26/2016] [Indexed: 11/15/2022]
Abstract
The question as to why a protein exerts oncogenic properties is answered mainly by well-established ideas that these proteins interfere with cellular signaling pathways. However, the knowledge about structural and functional peculiarities of the oncoproteins causing these effects is far from comprehensive. The 97.5% homologous tissue-specific A1 and A2 isoforms of mammalian translation elongation factor eEF1A represent an interesting model to study a difference between protein variants of a family that differ in oncogenic potential. We propose that the different oncogenic impact of A1 and A2 might be explained by differences in their ability to communicate with their respective cellular partners. Here we probed this hypothesis by studying the interaction of eEF1A with two known partners - calmodulin and actin. Indeed, an inability of the A2 isoform to interact with calmodulin is shown, while calmodulin is capable of binding A1 and interferes with its tRNA-binding and actin-bundling activities in vitro. Both A1 and A2 variants revealed actin-bundling activity; however, the form of bundles formed in the presence of A1 or A2 was distinctly different. Thus, a potential inability of A2 to be controlled by Ca2+-mediated regulatory systems is revealed.
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Ono S, Kume S, Yasuda-Yamahara M, Yamahara K, Takeda N, Chin-Kanasaki M, Araki H, Sekine O, Yokoi H, Mukoyama M, Uzu T, Araki SI, Maegawa H. O-linked β-N-acetylglucosamine modification of proteins is essential for foot process maturation and survival in podocytes. Nephrol Dial Transplant 2017; 32:1477-1487. [DOI: 10.1093/ndt/gfw463] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/02/2016] [Indexed: 11/14/2022] Open
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Swiatecka-Urban A. Endocytic Trafficking at the Mature Podocyte Slit Diaphragm. Front Pediatr 2017; 5:32. [PMID: 28286744 PMCID: PMC5324021 DOI: 10.3389/fped.2017.00032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 02/03/2017] [Indexed: 12/16/2022] Open
Abstract
Endocytic trafficking couples cell signaling with the cytoskeletal dynamics by organizing a crosstalk between protein networks in different subcellular compartments. Proteins residing in the plasma membrane are internalized and transported as cargo in endocytic vesicles (i.e., endocytosis). Subsequently, cargo proteins can be delivered to lysosomes for degradation or recycled back to the plasma membrane. The slit diaphragm is a modified tight junction connecting foot processes of the glomerular epithelial cells, podocytes. Signaling at the slit diaphragm plays a critical role in the kidney while its dysfunction leads to glomerular protein loss (proteinuria), manifesting as nephrotic syndrome, a rare condition with an estimated incidence of 2-4 new cases per 100,000 each year. Relatively little is known about the role of endocytic trafficking in podocyte signaling and maintenance of the slit diaphragm integrity. This review will focus on the role of endocytic trafficking at the mature podocyte slit diaphragm.
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Affiliation(s)
- Agnieszka Swiatecka-Urban
- Department of Nephrology, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA; Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Nagai K, Doi T. CIN85: Implications for the Development of Proteinuria in Diabetic Nephropathy. Diabetes 2016; 65:3532-3534. [PMID: 27879403 DOI: 10.2337/dbi16-0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Kojiro Nagai
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Toshio Doi
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
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Ubelmann F, Burrinha T, Salavessa L, Gomes R, Ferreira C, Moreno N, Guimas Almeida C. Bin1 and CD2AP polarise the endocytic generation of beta-amyloid. EMBO Rep 2016; 18:102-122. [PMID: 27895104 DOI: 10.15252/embr.201642738] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/14/2016] [Accepted: 10/19/2016] [Indexed: 01/31/2023] Open
Abstract
The mechanisms driving pathological beta-amyloid (Aβ) generation in late-onset Alzheimer's disease (AD) are unclear. Two late-onset AD risk factors, Bin1 and CD2AP, are regulators of endocytic trafficking, but it is unclear how their endocytic function regulates Aβ generation in neurons. We identify a novel neuron-specific polarisation of Aβ generation controlled by Bin1 and CD2AP We discover that Bin1 and CD2AP control Aβ generation in axonal and dendritic early endosomes, respectively. Both Bin1 loss of function and CD2AP loss of function raise Aβ generation by increasing APP and BACE1 convergence in early endosomes, however via distinct sorting events. When Bin1 levels are reduced, BACE1 is trapped in tubules of early endosomes and fails to recycle in axons. When CD2AP levels are reduced, APP is trapped at the limiting membrane of early endosomes and fails to be sorted for degradation in dendrites. Hence, Bin1 and CD2AP keep APP and BACE1 apart in early endosomes by distinct mechanisms in axon and dendrites. Individuals carrying variants of either factor would slowly accumulate Aβ in neurons increasing the risk for late-onset AD.
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Affiliation(s)
- Florent Ubelmann
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Tatiana Burrinha
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Laura Salavessa
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Ricardo Gomes
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Cláudio Ferreira
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Nuno Moreno
- Advance Imaging Lab, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Cláudia Guimas Almeida
- Neuronal Trafficking in Aging Lab, CEDOC, Chronic Diseases Research Centre, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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Hasegawa Y, Yoshida D, Nakamura Y, Sakakibara SI. Spatiotemporal distribution of SUMOylation components during mouse brain development. J Comp Neurol 2015; 522:3020-36. [PMID: 24639124 DOI: 10.1002/cne.23563] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/03/2014] [Accepted: 02/11/2014] [Indexed: 02/03/2023]
Abstract
Posttranslational modification of proteins might play an important role in brain cellular dynamics via the rapid turnover or functional change of critical proteins controlling neuronal differentiation or synaptic transmission. Small ubiquitin-like modifier protein (SUMO) is a family of ubiquitin-like small proteins that are covalently attached to target proteins to modify their function posttranslationally. Many cellular processes, such as transcription and protein trafficking, are regulated by SUMOylation, but its functional significance in the brain remains unclear. Although developmental regulation of SUMOylation levels in rat brain was recently demonstrated, no comparative immunohistochemical analysis of the cellular distribution profiles of SUMOylation components, including SUMO1, SUMO2/3, and Ubc9, has been undertaken so far. The present study used immunohistochemical and immunoblot analysis with the different developmental stages of mice and demonstrated the developmentally regulated distribution of SUMO1, SUMO2/3, and Ubc9 in the brain. During embryonic development, SUMOylation by SUMO1 and SUMO2/3 occurred in the nucleoplasm of nestin-positive neural stem cells. Although the total amount of SUMO-modified proteins decreased during postnatal brain development, intense and persistent accumulation of SUMO2/3 was detected throughout life in neural progenitor populations in neurogenic regions, including the subventricular zone and the hippocampal subgranular zone. In contrast, many neurons in the adult brain accumulated SUMO1 rather than SUMO2/3. Heavy immunoreactivity of SUMO1 was found in large projection neurons in the brainstem, whereas SUMO2/3 was almost absent from these areas. This heterogeneous distribution implies that both proteins play a specific and unique role in the brain.
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Affiliation(s)
- Yuta Hasegawa
- Laboratory for Molecular Neurobiology, Graduate School of Human Sciences, Waseda University, Saitama, 359-1192, Japan
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An update: the role of Nephrin inside and outside the kidney. SCIENCE CHINA-LIFE SCIENCES 2015; 58:649-57. [PMID: 25921941 DOI: 10.1007/s11427-015-4844-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 02/27/2015] [Indexed: 12/18/2022]
Abstract
Nephrin is a key molecule in podocytes to maintain normal slit diaphragm structure. Nephin interacts with many other podocyte and slit diaphragm protein and also mediates important cell signaling pathways in podocytes. Loss of nephrin during the development leads to the congenital nephrotic syndrome in children. Reduction of nephrin expression is often observed in adult kidney diseases including diabetic nephropathy and HIV-associated nephropathy. The critical role of nephrin has been confirmed by different animal models with nephrin knockout and knockdown. Recent studies demonstrate that knockdown of nephrin expression in adult mice aggravates the progression of unilateral nephrectomy and Adriamycin-induced kidney disease. In addition to its critical role in maintaining normal glomerular filtration unit in the kidney, nephrin is also expressed in other organs. However, the exact role of nephrin in kidney and extra-renal organs has not been well characterized. Future studies are required to determine whether nephrin could be developed as a drug target to treat patients with kidney disease.
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Podocin is translocated to cytoplasm in puromycin aminonucleoside nephrosis rats and in poor-prognosis patients with IgA nephropathy. Cell Tissue Res 2015; 360:391-400. [PMID: 25676004 PMCID: PMC4544490 DOI: 10.1007/s00441-014-2100-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 12/18/2014] [Indexed: 11/02/2022]
Abstract
Podocytes serve as the final barrier to urinary protein loss through a highly specialized structure called a slit membrane and maintain foot process and glomerular basement membranes. Podocyte injury results in progressive glomerular damage and accelerates sclerotic changes, although the exact mechanism of podocyte injury is still obscure. We focus on the staining gap (podocin gap) defined as the staining difference between podocin and synaptopodin, which are normally located in the foot process. In puromycin aminonucleoside nephrosis rats, the podocin gap is significantly increased (p < 0.05) and podocin is translocated to the cytoplasm on days 7 and 14 but not on day 28. Surprisingly, the gap is also significantly increased (p < 0.05) in human kidney biopsy specimens of poor-prognosis IgA nephropathy patients. This suggests that the podocin gap could be a useful marker for classifying the prognosis of IgA nephropathy and indicating the translocation of podocin to the cytoplasm. Next, we find more evidence of podocin trafficking in podocytes where podocin merges with Rab5 in puromycin aminonucleoside nephrosis rats at day 14. In immunoelectron microscopy, the podocin positive area was significantly translocated from the foot process areas to the cytoplasm (p< 0.05) on days 7 and 14 in puromycin aminonucleoside nephrosis rats. Interestingly, podocin is also translocated to the cytoplasm in poor-prognosis human IgA nephropathy. In this paper, we demonstrate that the translocation of podocin by endocytosis could be a key traffic event of critical podocyte injury and that the podocin gap could indicate the prognosis of IgA nephropathy.
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Song Y, Jiang J, Vermeren S, Tong W. ARAP3 functions in hematopoietic stem cells. PLoS One 2014; 9:e116107. [PMID: 25542002 PMCID: PMC4277471 DOI: 10.1371/journal.pone.0116107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 12/05/2014] [Indexed: 11/25/2022] Open
Abstract
ARAP3 is a GTPase-activating protein (GAP) that inactivates Arf6 and RhoA small GTPases. ARAP3 deficiency in mice causes a sprouting angiogenic defect resulting in embryonic lethality by E11. Mice with an ARAP3 R302,303A mutation (Arap3KI/KI) that prevents activation by phosphoinositide-3-kinase (PI3K) have a similar angiogenic phenotype, although some animals survive to adulthood. Here, we report that hematopoietic stem cells (HSCs) from rare adult Arap3KI/KI bone marrow are compromised in their ability to reconstitute recipient mice and to self-renew. To elucidate the potential cell-autonomous and non-cell-autonomous roles of ARAP3 in hematopoiesis, we conditionally deleted Arap3 in hematopoietic cells and in several cell types within the HSC niche. Excision of Arap3 in hematopoietic cells using Vav1-Cre does not alter the ability of ARAP3-deficient progenitor cells to proliferate and differentiate in vitro or ARAP3-deficient HSCs to provide multi-lineage reconstitution and to undergo self-renewal in vivo. Thus, our data suggest that ARAP3 does not play a cell-autonomous role in HSPCs. Deletion of Arap3 in osteoblasts and mesenchymal stromal cells using Prx1-Cre resulted in no discernable phenotypes in hematopoietic development or HSC homeostasis in adult mice. In contrast, deletion of Arap3 using vascular endothelial cadherin (VEC or Cdh5)-driven Cre resulted in embryonic lethality, however HSCs from surviving adult mice were largely normal. Reverse transplantations into VEC-driven Arap3 conditional knockout mice revealed no discernable difference in HSC frequencies or function in comparison to control mice. Taken together, our investigation suggests that despite a critical role for ARAP3 in embryonic vascular development, its loss in endothelial cells minimally impacts HSCs in adult bone marrow.
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Affiliation(s)
- Yiwen Song
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Jing Jiang
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Sonja Vermeren
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, The University of Edinburgh, United Kingdom
| | - Wei Tong
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Ollero M, Sahali D. Inhibition of the VEGF signalling pathway and glomerular disorders. Nephrol Dial Transplant 2014; 30:1449-55. [PMID: 25480873 DOI: 10.1093/ndt/gfu368] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 10/27/2014] [Indexed: 11/14/2022] Open
Abstract
Anti-cancer therapeutic approaches targeting the vascular endothelial growth factor (VEGF) ligand (anti-VEGF) or inhibiting its receptors (RTKI) have recently been developed. In spite of the promising results achieved, a serious drawback and dose-limiting side effect is the development, among others, of renal complications. This encompasses two glomerular pathological entities, namely minimal change/focal segmental glomerulosclerosis and thrombotic micro-angiopathy, involving two distinct cell types, podocytes and endothelial cells, respectively. The mechanisms that link anti-cancer therapy by RTKI to podocyte dysfunction and nephrotic level proteinuria are still poorly understood. Nevertheless, recent findings strongly suggest a central role of RelA, the master subunit of NF-κB and c-mip, an active player in podocyte disorders. RelA, which is up-regulated following anti-VEGF therapy, is inactivated by RTKI, leading to c-mip over-expression in the podocyte. This results in severe alterations in the architecture of podocyte actin cytoskeleton and subsequent severe proteinuria. Hence, clarifying the mechanisms linking c-mip and RelA as key pathogenic factors represents a critical goal in the understanding of different glomerulopathies. In the context of VEGF-targeted anti-cancer therapy, the study of these mechanisms along with the molecular cross-talk between podocyte and endothelial cell constitutes the basis for the emerging field of onconephrology.
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Affiliation(s)
- Mario Ollero
- INSERM, U955, Equipe 21, Créteil, France Université Paris-Est Créteil Val-de-Marne, Créteil, France
| | - Djillali Sahali
- INSERM, U955, Equipe 21, Créteil, France Université Paris-Est Créteil Val-de-Marne, Créteil, France AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, Service de Néphrologie, Créteil, France
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Abstract
PURPOSE OF REVIEW In this review, we discuss the role of endocytosis, a fundamental process internalizing molecules from the plasma membrane, and its critical importance in podocyte biology. RECENT FINDINGS Endocytic clathrin and nonclathrin-coated pits have been visualized in podocytes using electron microscopy, but the functional biological relevance has not been well defined. Recent evidence suggests that loss of key clathrin endocytic regulatory apparatus, such as dynamin, synaptojanin 1 or endophilin, in genetic mouse models of disease results in severe proteinuria and foot process effacement. In addition, several genes implicated in human nephrotic syndrome directly or indirectly associate with these endocytic proteins, thus creating a protein network that is linked in actin dynamics, signalling and endocytosis. SUMMARY This review summarizes our current understanding of membrane trafficking specifically in podocytes, thus giving further novel insights into the molecular mechanisms and pathogenesis of nephrotic syndrome.
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Affiliation(s)
- Keita Soda
- Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Swiatecka-Urban A. Membrane trafficking in podocyte health and disease. Pediatr Nephrol 2013; 28:1723-37. [PMID: 22932996 PMCID: PMC3578983 DOI: 10.1007/s00467-012-2281-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 12/21/2022]
Abstract
Podocytes are highly specialized epithelial cells localized in the kidney glomerulus. The distinct cell signaling events and unique cytoskeletal architecture tailor podocytes to withstand changes in hydrostatic pressure during glomerular filtration. Alteration of glomerular filtration leads to kidney disease and frequently manifests with proteinuria. It has been increasingly recognized that cell signaling and cytoskeletal dynamics are coupled more tightly to membrane trafficking than previously thought. Membrane trafficking coordinates the cross-talk between protein networks and signaling cascades in a spatially and temporally organized fashion and may be viewed as a communication highway between the cell exterior and interior. Membrane trafficking involves transport of cargo from the plasma membrane to the cell interior (i.e., endocytosis) followed by cargo trafficking to lysosomes for degradation or to the plasma membrane for recycling. Yet, recent studies indicate that the conventional classification does not fully reflect the complex and versatile nature of membrane trafficking. While the increasing complexity of elaborate protein scaffolds and signaling cascades is being recognized in podocytes, the role of membrane trafficking is less well understood. This review will focus on the role of membrane trafficking in podocyte health and disease.
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