1
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Ye S, Chin WC, Ni CW. A multi-depth spiral milli fluidic device for whole mount zebrafish antibody staining. Biomed Microdevices 2023; 25:30. [PMID: 37581716 PMCID: PMC10427545 DOI: 10.1007/s10544-023-00670-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Whole mount zebrafish antibody staining (ABS) is a common staining technique used to localize protein information in a zebrafish embryo or larva. Like most biological assays, the whole mount zebrafish ABS is still largely conducted manually through labor intensive and time-consuming steps which affect both consistency and throughput of the assay. In this work, we develop a milli fluidic device that can automatically trap and immobilize the fixed chorion-less zebrafish embryos for the whole mount ABS. With just a single loading step, the zebrafish embryos can be trapped by the milli fluidic device through a chaotic hydrodynamic trapping process. Moreover, a consistent body orientation (i.e., head point inward) for the trapped zebrafish embryos can be achieved without additional orientation adjustment device. Furthermore, we employed a consumer-grade SLA 3D printer assisted method for device prototyping which is ideal for labs with limited budgets. Notably, the milli fluidic device has enabled the optimization and successful implementation of whole mount zebrafish Caspase-3 ABS. We demonstrated our device can accelerate the overall procedure by reducing at least 50% of washing time in the standard well-plate-based manual procedure. Also, the consistency is improved, and manual steps are reduced using the milli fluidic device. This work fills the gap in the milli fluidic application for whole mount zebrafish immunohistochemistry. We hope the device can be accepted by the zebrafish community and be used for other types of whole mount zebrafish ABS procedures or expanded to more complicated in situ hybridization (ISH) procedure.
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Affiliation(s)
- Songtao Ye
- Quantitative and Systems Biology, University of California Merced, Merced, US
| | - Wei-Chun Chin
- Quantitative and Systems Biology, University of California Merced, Merced, US.
- Department of Bioengineering, University of California Merced, Merced, US.
| | - Chih-Wen Ni
- Quantitative and Systems Biology, University of California Merced, Merced, US
- Department of Bioengineering, University of California Merced, Merced, US
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2
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Shiu RF, Vazquez CI, Chiang CY, Chiu MH, Chen CS, Ni CW, Gong GC, Quigg A, Santschi PH, Chin WC. Nano- and microplastics trigger secretion of protein-rich extracellular polymeric substances from phytoplankton. Sci Total Environ 2020; 748:141469. [PMID: 33113698 DOI: 10.1016/j.scitotenv.2020.141469] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
The substantial increase in plastic pollution in marine ecosystems raises concerns about its adverse impacts on the microbial community. Microorganisms (bacteria, phytoplankton) are important producers of exopolymeric substances (EPS), which govern the processes of marine organic aggregate formation, microbial colonization, and pollutant mobility. Until now, the effects of nano- and micro-plastics on characteristics of EPS composition have received little attention. This study investigated EPS secretion by four phytoplankton species following exposure to various concentrations of polystyrene nano- and microplastics (55 nm nanoparticles; 1 and 6 μm microparticles). The 55 nm nanoparticles induced less growth/survival (determined on a DNA basis) and produced EPS with higher protein-to-carbohydrate (P/C) ratios than the exposure to microplastic particles. The amount of DNA from the four marine phytoplankton showed a higher negative linear correlation with increasing P/C ratios, especially in response to nanoplastic exposure. These results provide evidence that marine phytoplankton are quite sensitive to smaller-sized plastics and actively modify their EPS chemical composition to cope with the stress from pollution. Furthermore, the release of protein-rich EPS was found to facilitate aggregate formation and surface modification of plastic particles, thereby affecting their fate and colonization. Overall, this work offers new insights into the potential harm of different-sized plastic particles and a better understanding of the responding mechanism of marine phytoplankton for plastic pollution. The data also provide needed information about the fate of marine plastics and biogenic aggregation and scavenging processes.
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Affiliation(s)
- Ruei-Feng Shiu
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan
| | - Carlos I Vazquez
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Chang-Ying Chiang
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Meng-Hsuen Chiu
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA; National Life Science, Inc., Sacramento, CA 95660, USA; Kaiser Biotech, Inc., Sacramento, CA 95660, USA
| | - Chi-Shuo Chen
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chih-Wen Ni
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Gwo-Ching Gong
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan
| | - Antonietta Quigg
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553, USA; Department of Oceanography, Texas A&M University, College Station, TX 77843, USA
| | - Peter H Santschi
- Department of Oceanography, Texas A&M University, College Station, TX 77843, USA; Department of Marine and Coastal Environmental Science, Texas A&M University at Galveston, Galveston, TX 77553, USA
| | - Wei-Chun Chin
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA.
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3
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Chiang CY, Ligunas GD, Chin WC, Ni CW. Efficient Nonviral Stable Transgenesis Mediated by Retroviral Integrase. Mol Ther Methods Clin Dev 2020; 17:1061-1070. [PMID: 32462054 PMCID: PMC7240061 DOI: 10.1016/j.omtm.2020.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 04/27/2020] [Indexed: 11/28/2022]
Abstract
Efficient transgene delivery is critical for genetic manipulation and therapeutic intervention of target cells. Two well-characterized integrative systems have been described that rely on viral and nonviral vectors. However, use of viral vectors for gene therapy has been associated with several safety concerns. Here, we report a virus-free method for stable transgenesis based on the reaction of retroviral integrase. We constructed a gateway cloning compatible vector containing two truncated long terminal repeat (LTR) sequences (dLTR) that flank the transgene cassette. Notably, 5′-ACTG-3′ and blunt-end restriction cutting sites were also embedded at the end of dLTR to be recognized by HIV-1 integrase. When performing coinjection of transgene cassette and integrase mRNA into zebrafish embryos at one cell stage, there were 50% to 55% of injected embryos expressing a marker gene in a desired pattern. When applying our method in mammalian cells, there were 42% of cultured human epithelial cell lines showing stable integration. These results demonstrated that our method can successfully insert an exogenous gene into the host genome with highly efficient integration. Importantly, this system operates without most of the viral components while retaining effective stable transgenesis. We anticipate this method will provide a convenient, safe, and highly efficient way for applications in transgenesis and gene therapy.
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Affiliation(s)
- Chang-Ying Chiang
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, USA
| | - Gloria Denise Ligunas
- Program of Quantitative and Systems Biology, University of California, Merced, Merced, CA, USA
| | - Wei-Chun Chin
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, USA.,Program of Quantitative and Systems Biology, University of California, Merced, Merced, CA, USA
| | - Chih-Wen Ni
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, USA.,Program of Quantitative and Systems Biology, University of California, Merced, Merced, CA, USA
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4
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Shmukler BE, Huston NC, Thon JN, Ni CW, Kourkoulis G, Lawson ND, Paw BH, Alper SL. Homozygous knockout of the piezo1 gene in the zebrafish is not associated with anemia. Haematologica 2015; 100:e483-5. [PMID: 26294733 DOI: 10.3324/haematol.2015.132449] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Boris E Shmukler
- Renal Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Nicholas C Huston
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jonathan N Thon
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chih-Wen Ni
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA, USA
| | - George Kourkoulis
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA, USA
| | - Nathan D Lawson
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA, USA
| | - Barry H Paw
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA Hematology-Oncology Division, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Seth L Alper
- Renal Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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5
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Ni CW, Kim CW, Jang I, Jo H, Lawson ND. Abstract 234: Ramp2 Is a Novel Flow-sensitive Gene Both In vitro and in vivo. Arterioscler Thromb Vasc Biol 2015. [DOI: 10.1161/atvb.35.suppl_1.234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ramp2 is a member of ramps (receptor activity modified proteins) family, which comprises a single transmembrane domain and involves in protein transport. Specifically, ramp2 is required to transport calcitonin-receptor-like receptor (CRLR) to the plasma membrane, which can function as an adrenomedullin receptor. In addition, ramp2 significantly expresses in endothelial cells but the function of ramp2 in endothelium in response to blood flow has not been reported yet. Here, we first report the expression of ramp2 is significantly altered by different flow conditions. In cultured HUVECs, ramp2 mRNA level decreases over 90% (p<0.01) in oscillatory shear (OS) flow compared to laminar shear (LS). Similarly, ramp2 is down-regulated (reduced 79%, p<0.01) under low and oscillatory shear condition in vivo when performing partial carotid ligation in mouse model. Moreover, a very similar result was obtained from deep sequencing data acquired in zebrafish. Zebrafish embryos were left untreated or injected with tnnt2 morpholinos at one-cell stage that in turn prevents heart beating and stops blood flow. We developed a method to acquire endothelial-enriched mRNAs from these embryos at 2 days post fertilization (dpf), and then samples were subjected to deep sequencing analysis. The data showed that ramp2 decreases 60% (p<0.01) at no flow condition, which is consistent with the observation in mouse and cultured human cells. Together, these data suggests that ramp2 is a novel flow-sensitive gene despite the detail function and significance is still to be determined.
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Affiliation(s)
- Chih-Wen Ni
- Biomedical Engineering, Khalifa Univ, Abu Dhabi, United Arab Emirates
| | | | - Inhwan Jang
- Biomedical Engineering, Emory Univ, Atlanta, GA
| | - Hanjoong Jo
- Biomedical Engineering, Emory Univ, Atlanta, GA
| | - Nathan D Lawson
- Program of Gene Function and Expression, UMass Med Sch, Worcester, MA
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6
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Butko E, Distel M, Pouget C, Weijts B, Kobayashi I, Ng K, Mosimann C, Poulain FE, McPherson A, Ni CW, Stachura DL, Del Cid N, Espín-Palazón R, Lawson ND, Dorsky R, Clements WK, Traver D. Gata2b is a restricted early regulator of hemogenic endothelium in the zebrafish embryo. Development 2015; 142:1050-61. [PMID: 25758220 PMCID: PMC4360177 DOI: 10.1242/dev.119180] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/29/2015] [Indexed: 12/13/2022]
Abstract
The adult blood system is established by hematopoietic stem cells (HSCs), which arise during development from an endothelial-to-hematopoietic transition of cells comprising the floor of the dorsal aorta. Expression of aortic runx1 has served as an early marker of HSC commitment in the zebrafish embryo, but recent studies have suggested that HSC specification begins during the convergence of posterior lateral plate mesoderm (PLM), well before aorta formation and runx1 transcription. Further understanding of the earliest stages of HSC specification necessitates an earlier marker of hemogenic endothelium. Studies in mice have suggested that GATA2 might function at early stages within hemogenic endothelium. Two orthologs of Gata2 exist in zebrafish: gata2a and gata2b. Here, we report that gata2b expression initiates during the convergence of PLM, becoming restricted to emerging HSCs. We observe Notch-dependent gata2b expression within the hemogenic subcompartment of the dorsal aorta that is in turn required to initiate runx1 expression. Our results indicate that Gata2b functions within hemogenic endothelium from an early stage, whereas Gata2a functions more broadly throughout the vascular system.
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Affiliation(s)
- Emerald Butko
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Martin Distel
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Claire Pouget
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Bart Weijts
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Isao Kobayashi
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Kevin Ng
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Christian Mosimann
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Fabienne E Poulain
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Adam McPherson
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Chih-Wen Ni
- University of Massachusetts at Worcester, Worcester, MA 01605, USA
| | - David L Stachura
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Natasha Del Cid
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Raquel Espín-Palazón
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Nathan D Lawson
- University of Massachusetts at Worcester, Worcester, MA 01605, USA
| | - Richard Dorsky
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Wilson K Clements
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA Department of Hematology, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - David Traver
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093, USA
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7
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Kanthi Y, Hyman M, Liao H, Baek A, Visovatti S, Sutton N, Takabe W, Ni CW, Jo H, Pinsky D. Abstract 13: Suppression of Atherosclerosis by CD39. Arterioscler Thromb Vasc Biol 2014. [DOI: 10.1161/atvb.34.suppl_1.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Atherosclerotic plaque rupture and thrombosis remains the leading cause of death in the United States. We investigated the role of CD39, a potent ecto-enzymatic regulator of platelet activation and leukocyte trafficking, in atherosclerosis. We generated mice deficient in CD39 on a hyperlipidemic,
apoE
-/-
background and noted a two-fold higher plaque burden in when compared to
apoE
-/-
controls (
P
=0.003). We noted higher levels of circulating markers of platelet activation, soluble P-selectin (39%) and RANTES (60%), in the CD39-deficient mice (
P
=0.003 and
P
=0.015, respectively, n=7-11). CD39-haploinsufficient mice had 1.8-fold greater enhanced platelet reactivity in response to ADP compared to controls (
P
=0.03, n=3-8). Macrophages from CD39-deficient mice had significantly higher lipoprotein uptake
in vitro
. Correspondingly, CD39 overexpression in RAW cells inhibited scavenger receptor expression and lipoprotein uptake.
Altered fluid mechanics contribute to atherosclerosis, with non-laminar shear stress enhancing regional plaque formation as seen in arterial bifurcations. We examined coronal sections of aortas from
apoE
−/−
mice and observed that CD39 is poorly expressed in the endothelium in regions of turbulent blood flow, where plaque develops, supporting our hypothesis that endothelial CD39 can be induced by fluid phase shear forces. HUVEC treated with physiologic laminar shear stress (LS) (15 dynes/cm
2
) had a 5.9-fold increase in CD39 protein (
P
=0.004, N=3-7) and a concordant increase in nucleotidase activity (
P
=0.03 N=3) compared to static controls (SS). We identified Krüppel like factor 2 (KLF2) as an upstream candidate for transcriptional regulation of CD39 induction by fluid shear forces. Silencing KLF2
in vitro
led to a 55% decrease in CD39 mRNA induction with LS vs SS controls (
P
=0.002, N=3-4). Chromatin immunoprecipitation revealed that KLF2 binds to the CD39 (
P
=0.01, N=3) and this binding was further enhanced under laminar shear stress (
P
=0.0007, N=3). These data show that CD39, an anti-thrombotic, anti-inflammatory enzyme is a critical regulator of atherosclerosis by modulating platelet, macrophage and endothelial function and mechanistically identify KLF2 as a direct, upstream regulator of CD39 expression.
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Affiliation(s)
- Yogendra Kanthi
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Michigan Health System, Ann Arbor, MI
| | - Matthew Hyman
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Pennsylvania, Philadelphia, PA
| | - Hui Liao
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Michigan Health System, Ann Arbor, MI
| | - Amy Baek
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Michigan Health System, Ann Arbor, MI
| | - Scott Visovatti
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Michigan Health System, Ann Arbor, MI
| | - Nadia Sutton
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Michigan Health System, Ann Arbor, MI
| | - Wakako Takabe
- Div of Cardiology, Biomedical Engineering, Emory, Atlanta, GA
| | - Chih-Wen Ni
- Div of Cardiology, Biomedical Engineering, Emory Univ Sch of Medicine, Atlanta, GA
| | - Hanjoong Jo
- Div of Cardiology, Biomedical Engineering, Emory Univ Sch of Medicine, Atlanta, GA
| | - David Pinsky
- Dept of Internal Medicine, Div of Cardiovascular Medicine, Univ of Michigan Health System, Ann Arbor, MI
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8
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Ni CW, Smith T, Lawson ND. Abstract 174: Lacking Gata2 in Endothelial Cells Induces Apoptosis During Vascular Development. Arterioscler Thromb Vasc Biol 2014. [DOI: 10.1161/atvb.34.suppl_1.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gata2 is a transcription factor implicated in hematopoietic development. Previously, we utilized zinc-finger nucleases to generate a zebrafish mutant in gata2a, which reveals a novel role for this gene in vascular development. In particular, gata2a mutant embryos exhibit defects in blood flow circulation due to the formation of shunts within trunk blood vessels, although artery and vein identity appears normal. Here, we show that endothelial cells in gata2a mutant embryos specifically undergo apoptosis as revealed by positive staining of activated caspase-3 at 30hpf but not 24hpf. This endothelial apoptosis can be rescued by re-constitution of gata2a or overexpression of a well-known anti-apoptotic protein, bcl2l1. Interestingly, knocking-down p53 has no effect on the rescue of apoptosis in gata2a mutants, suggesting a p53 independent pathway of apoptosis. Furthermore, we find that mouse retinal vascular endothelial cells lacking gata2 also appear to undergo apoptosis, which prevent angiogenic sprouting from the superficial to media layer of retina vasculature. These findings reveal a new role of gata2 in vascular development whereby gata2 retains an anti-apoptotic function in endothelial cells.
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Affiliation(s)
- Chih-Wen Ni
- Biomedical Engineering, Khalifa Univ, Abu Dhabi, United Arab Emirates
| | - Tom Smith
- Program of Gene Function and Expression, Univ of Massachusetts Med Sch, Worcester, MA
| | - Nathan D Lawson
- Program of Gene Function and Expression, Univ of Massachusetts Med Sch, Worcester, MA
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9
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Abstract
Background The understanding of endothelial cell biology has been facilitated by the availability of primary endothelial cell cultures from a variety of sites and species; however, the isolation and maintenance of primary mouse aortic endothelial cells (MAECs) remain a formidable challenge. Culturing MAECs is difficult as they are prone to phenotypic drift during culture. Therefore, there is a need to have a dependable in vitro culture system, wherein the primary endothelial cells retain their properties and phenotypes. Methods Here, we developed an effective method to prepare immortalized MAEC (iMAEC) lines. Primary MAECs, initially isolated from aortic explants, were immortalized using a retrovirus expressing polyoma middle T-antigen. Immortalized cells were then incubated with DiI-acetylated-low density lipoprotein and sorted via flow cytometry to isolate iMAECs. Results iMAECs expressed common markers of endothelial cells, including PECAM1, eNOS, VE-cadherin, and von Willebrand Factor. iMAECs aligned in the direction of imposed laminar shear and retained the ability to form tubes. Using this method, we have generated iMAEC lines from wild-type and various genetically modified mice such as p47phox-/-, eNOS-/-, and caveolin-1-/-. Conclusion In summary, generation of iMAEC lines from various genetically modified mouse lines provides an invaluable tool to study vascular biology and pathophysiology.
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Affiliation(s)
| | | | | | - Hanjoong Jo
- Wallace H, Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory University, 1760 Haygood Drive, Health Science Research Building, E-170, Atlanta, GA 30322, USA.
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10
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Fazeli G, Stopper H, Schinzel R, Ni CW, Jo H, Schupp N. Angiotensin II induces DNA damage via AT1 receptor and NADPH oxidase isoform Nox4. Mutagenesis 2012; 27:673-81. [PMID: 22844079 DOI: 10.1093/mutage/ges033] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Epidemiological studies revealed increased renal cancer incidences and higher cancer mortalities in hypertensive individuals. Activation of the renin-angiotensin-aldosterone system leads to the formation of reactive oxygen species (ROS). In vitro, in renal cells, and ex vivo, in the isolated perfused mouse kidney, we could show DNA-damaging potential of angiotensin II (Ang II). Here, the pathway involved in the genotoxicity of Ang II was investigated. In kidney cell lines with properties of proximal tubulus cells, an activation of NADPH oxidase and the production of ROS, resulting in the formation of DNA strand breaks and micronuclei induction, was observed. This DNA damage was mediated by the Ang II type 1 receptor (AT1R), together with the G protein G ( α-q/11 ) . Subsequently, phospholipase C (PLC) was activated and intracellular calcium increased. Both calcium stores of the endoplasmic reticulum and extracellular calcium were involved in the genotoxicity of Ang II. Downstream, a role for protein kinase C (PKC) could be detected, because its inhibition hindered Ang II from damaging the cells. Although PKC was activated, no involvement of its known target, the NADPH oxidase isoform containing the Nox2 subunit, could be found, as tested by small-interfering RNA down-regulation. Responsible for the DNA-damaging activity of Ang II was the NADPH oxidase isoform containing the Nox4 subunit. In summary, in kidney cells the DNA-damaging activity of Ang II depends on an AT1R-mediated activation of NADPH oxidase via PLC, PKC and calcium signalling, with the NADPH subunit Nox4 playing a crucial role.
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Affiliation(s)
- Gholamreza Fazeli
- Institute of Pharmacology and Toxicology, Versbacher Str. 9, University of Würzburg, 97078 Würzburg, Germany
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11
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Takabe W, Ni CW, Son DJ, Alberts-Grill N, Jo H. Abstract 363: Lim Domain Only 4 Is a Shear-Sensitive Protein, Playing a Critical Role in Endothelial Inflammation and Atherosclerosis. Arterioscler Thromb Vasc Biol 2012. [DOI: 10.1161/atvb.32.suppl_1.a363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recently, we have shown that disturbed flow, characterized by low and oscillatory shear stress, caused by a partial ligation of mouse left carotid artery (LCA) rapidly induces atherosclerosis. Using the partial ligation model and genome-wide microarray study with aortic endothelial RNAs obtained directly from the flow-disturbed carotid arteries, we previously identified mechanosensitive genes in mouse endothelial RNA including
LIM domain only 4
(
lmo4
). Here we report that LMO4 is a shear-sensitive protein that regulates endothelial inflammation.
Lmo4
was up-regulated by disturbed flow in mouse LCA compared to the contralateral right CA (RCA) exposed to stable flow. At protein levels, LMO4 expression was significantly higher not only in LCA in our surgical model but also in the lesser curvature (flow-disturbed and athero-prone region of mouse aortic arch) compared to the greater curvature (stable-flow and ather-protected region). In addition, immunohistochemical staining of LMO4 in human coronary arteries revealed that its expression is detectable only in intimal endothelial cells, but not in medial cells. While LMO4 is known as a potential oncogene and associated with growth, migration and invasion of breast cancer cells, its role in cardiovascular system is not known to our knowledge. We tested a hypothesis that LMO4 is a mechanosensitive gene and plays a critical role in regulation of endothelial cell biology. LMO4 protein expression was robustly induced by oscillatory shear stress (OS) compared to laminar shear (LS) in human umbilical vein endothelial cells (HUVEC). Treatment of HUVEC with siRNA against LMO4 significantly inhibited OS-induced inflammation and migration, but not apoptosis and cell cycle progression. Further, LMO4 siRNA treatment significantly blunted expression of VCAM-1 and interleukin-8 induced by OS in endothelial cells. These results suggest that LMO4 is a shear-induced gene that plays a critical role in OS-induced endothelial inflammation and migration, and potentially in atherosclerosis.
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Affiliation(s)
| | - Chih-Wen Ni
- Dept of Medicine, Univ of Massachusetts, Worcester, MA
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12
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Abstract
Atherosclerosis is an inflammatory disease preferentially occurring in curved or branched arterial regions, whereas straight parts of the arteries are protected, suggesting a close relationship between flow and atherosclerosis. However, evidence directly linking disturbed flow to atherogenesis is just emerging, thanks to the recent development of suitable animal models. In this article, we review the status of various animal, in vitro, and ex vivo models that have been used to study flow-dependent vascular biology and atherosclerosis. For animal models, naturally flow-disturbed regions such as branched or curved arterial regions as well as surgically created models, including arterio-venous fistulas, vascular grafts, perivascular cuffs, and complete, incomplete, or partial ligation of arteries, are used. Although in vivo models provide the environment needed to mimic the complex pathophysiological processes, in vitro models provide simple conditions that allow the study of isolated factors. Typical in vitro models use cultured endothelial cells exposed to various flow conditions, using devices such as cone-and-plate and parallel-plate chambers. Ex vivo models using isolated vessels have been used to bridge the gap between complex in vivo models and simple in vitro systems. Here, we review these flow models in the context of the role of oxidative stress in flow-dependent inflammation, a critical proatherogenic step, and atherosclerosis.
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Affiliation(s)
- Amir Rezvan
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, Georgia 30322, USA
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13
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Ni CW, Qiu H, Jo H. MicroRNA-663 upregulated by oscillatory shear stress plays a role in inflammatory response of endothelial cells. Am J Physiol Heart Circ Physiol 2011; 300:H1762-9. [PMID: 21378144 DOI: 10.1152/ajpheart.00829.2010] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mechanisms by which oscillatory shear stress (OS) induces, while high laminar shear stress (LS) prevents, atherosclerosis are still unclear. Here, we examined the hypothesis that OS induces inflammatory response, a critical atherogenic event, in endothelial cells by a microRNA (miRNA)-dependent mechanism. By miRNA microarray analysis using total RNA from human umbilical vein endothelial cells (HUVECs) that were exposed to OS or LS for 24 h, we identified 21 miRNAs that were differentially expressed. Of the 21 miRNAs, 13 were further examined by quantitative PCR, which validated the result for 10 miRNAs. Treatment of HUVECs with the miR-663 antagonist (miR-663-locked nucleic acids) blocked OS-induced monocyte adhesion, but not apoptosis. In contrast, overexpression of miR-663 increased monocyte adhesion in LS-exposed cells. Subsequent mRNA expression microarray study using HUVECs treated with miR-663-locked nucleic acids and OS revealed 32 up- and 3 downregulated genes, 6 of which are known to be involved in inflammatory response. In summary, we identified 10 OS-sensitive miRNAs, including miR-663, which plays a key role in OS-induced inflammatory responses by mediating the expression of inflammatory gene network in HUVECs. These OS-sensitive miRNAs may mediate atherosclerosis induced by disturbed flow.
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Affiliation(s)
- Chih-Wen Ni
- Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA, USA
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14
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Ni CW, Qiu H, Rezvan A, Kwon K, Nam D, Son DJ, Visvader JE, Jo H. Discovery of novel mechanosensitive genes in vivo using mouse carotid artery endothelium exposed to disturbed flow. Blood 2010; 116:e66-73. [PMID: 20551377 PMCID: PMC2974596 DOI: 10.1182/blood-2010-04-278192] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 05/19/2010] [Indexed: 02/01/2023] Open
Abstract
Recently, we showed that disturbed flow caused by a partial ligation of mouse carotid artery rapidly induces atherosclerosis. Here, we identified mechanosensitive genes in vivo through a genome-wide microarray study using mouse endothelial RNAs isolated from the flow-disturbed left and the undisturbed right common carotid artery. We found 62 and 523 genes that changed significantly by 12 hours and 48 hours after ligation, respectively. The results were validated by quantitative polymerase chain reaction for 44 of 46 tested genes. This array study discovered numerous novel mechanosensitive genes, including Lmo4, klk10, and dhh, while confirming well-known ones, such as Klf2, eNOS, and BMP4. Four genes were further validated for protein, including LMO4, which showed higher expression in mouse aortic arch and in human coronary endothelium in an asymmetric pattern. Comparison of in vivo, ex vivo, and in vitro endothelial gene expression profiles indicates that numerous in vivo mechanosensitive genes appear to be lost or dysregulated during culture. Gene ontology analyses show that disturbed flow regulates genes involved in cell proliferation and morphology by 12 hours, followed by inflammatory and immune responses by 48 hours. Determining the functional importance of these novel mechanosensitive genes may provide important insights into understanding vascular biology and atherosclerosis.
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Affiliation(s)
- Chih-Wen Ni
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
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15
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Kim J, Ahn S, Ko YG, Boo YC, Chi SG, Ni CW, Go YM, Jo H, Park H. X-linked inhibitor of apoptosis protein controls α5-integrin-mediated cell adhesion and migration. Am J Physiol Heart Circ Physiol 2010; 299:H300-9. [DOI: 10.1152/ajpheart.00180.2010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The association of integrins with caveolin-1 regulates cell adhesion. However, the vascular ramifications of this association remain to be clearly determined. We recently reported that the X chromosome-linked inhibitor of apoptosis protein (XIAP)-caveolin-1 interaction is critical to endothelial cell survival. Thus, we hypothesized that XIAP performs a crucial function in integrin/caveolin-1-mediated endothelial cell survival. In this study, we demonstrated that XIAP is recruited into the α5-integrin complex via caveolin-1 binding and mediates cell adhesion. We also determined that XIAP is critical to shear stress-stimulated ERK activation in an α5-integrin-dependent manner but is not important to VEGF-induced ERK activation. This differential activation of ERK is partly attributable to unique localizations of the receptors. Furthermore, we confirmed that XIAP is an essential molecule in the efficient recruitment of focal adhesion kinase (FAK) into the α5-integrin-associated complex. This α5-integrin-caveolin-1-XIAP-FAK multicomplex regulates endothelial cell migration via a mechanism that involves shear-dependent ERK activation. Together, our results indicate that XIAP stabilizes the α5-integrin-associated focal adhesion complex, thereby further regulating endothelial cell adhesion and migration. The findings of this study provide us with greater insight into the molecular mechanisms underlying the control of vascular function by integrins.
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Affiliation(s)
- Jongmin Kim
- Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, Yongin
| | - Sunyoung Ahn
- Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, Yongin
| | - Young-Gyu Ko
- School of Life Sciences and Biotechnology, Korea University, Seoul
| | - Yong Chool Boo
- Department of Molecular Medicine and Cell and Matrix Research Institute, Kyungpook National University School of Medicine, Daegu, Korea; and
| | - Sung-Gil Chi
- School of Life Sciences and Biotechnology, Korea University, Seoul
| | - Chih-Wen Ni
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Tech and Emory University,
| | | | - Hanjoong Jo
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Tech and Emory University,
- Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia
| | - Heonyong Park
- Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, Yongin
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Nam D, Ni CW, Rezvan A, Suo J, Budzyn K, Llanos A, Harrison DG, Giddens DP, Jo H. A model of disturbed flow-induced atherosclerosis in mouse carotid artery by partial ligation and a simple method of RNA isolation from carotid endothelium. J Vis Exp 2010:1861. [PMID: 20613706 DOI: 10.3791/1861] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Despite the well-known close association, direct evidence linking disturbed flow to atherogenesis has been lacking. We have recently used a modified version of carotid partial ligation methods to show that it acutely induces low and oscillatory flow conditions, two key characteristics of disturbed flow, in the mouse common carotid artery. Using this model, we have provided direct evidence that disturbed flow indeed leads to rapid and robust atherosclerosis development in Apolipoprotein E knockout mouse. We also developed a method of endothelial RNA preparation with high purity from the mouse carotid intima. Using this mouse model and method, we found that partial ligation causes endothelial dysfunction in a week, followed by robust and rapid atheroma formation in two weeks in a hyperlipidemic mouse model along with features of complex lesion formation such as intraplaque neovascularization by four weeks. This rapid in vivo model and the endothelial RNA preparation method could be used to determine molecular mechanisms underlying flow-dependent regulation of vascular biology and diseases. Also, it could be used to test various therapeutic interventions targeting endothelial dysfunction and atherosclerosis in considerably reduced study duration.
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Affiliation(s)
- Douglas Nam
- Department of Medicine, Division of Cardiology, Emory University, USA
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17
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Bond AR, Ni CW, Jo H, Weinberg PD. Intimal cushions and endothelial nuclear elongation around mouse aortic branches and their spatial correspondence with patterns of lipid deposition. Am J Physiol Heart Circ Physiol 2009; 298:H536-44. [PMID: 19933414 DOI: 10.1152/ajpheart.00917.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Spatial variation in hemodynamic stresses acting on the arterial wall may explain the nonuniform distribution of atherosclerosis. In thoracic aortas of LDL receptor/apolipoprotein E double knockout mice, lesions develop preferentially around the entire circumference of intercostal branch ostia, regardless of age, with the highest prevalence occurring upstream. Additional chevron-shaped lesions occur further upstream of the ostia. This pattern differs from the age-related ones occurring in people and rabbits. In the present study, patterns of near-wall blood flow around intercostal ostia in wild-type mice were estimated from the morphology of endothelial nuclei, which were shown in vitro to elongate in response to elevated shear stress and to align with the flow, and wall structure was assessed from confocal and scanning electron microscopy. A triangular intimal cushion surrounded the upstream part of most ostia. Nuclear length-to-width ratios were lowest over this cushion and highest at the sides of branches, regardless of age. Nuclear orientations were consistent with flow diverging around the branch. The pattern of nuclear morphology differed from the age-related ones observed in rabbits. The intimal cushion and the distribution of shear stress inferred from these observations can partly account for the pattern of lesions observed in knockout mice. Nuclear elongation in nonbranch regions was approximately constant across animals of different size, demonstrating the existence of a mechanism by which endothelial cells compensate for the dependence of mean aortic wall shear stress on body mass.
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Affiliation(s)
- Andrew R Bond
- Department of Bioengineering, Imperial College London, London, United Kingdom
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Nam D, Ni CW, Rezvan A, Suo J, Budzyn K, Llanos A, Harrison D, Giddens D, Jo H. Partial carotid ligation is a model of acutely induced disturbed flow, leading to rapid endothelial dysfunction and atherosclerosis. Am J Physiol Heart Circ Physiol 2009; 297:H1535-43. [PMID: 19684185 DOI: 10.1152/ajpheart.00510.2009] [Citation(s) in RCA: 352] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Atherosclerosis is closely associated with disturbed flow characterized by low and oscillatory shear stress, but studies directly linking disturbed flow to atherogenesis is lacking. The major reason for this has been a lack of an animal model in which disturbed flow can be acutely induced and cause atherosclerosis. Here, we characterize partial carotid ligation as a model of disturbed flow with characteristics of low and oscillatory wall shear stress. We also describe a method of isolating intimal RNA in sufficient quantity from mouse carotid arteries. Using this model and method, we found that partial ligation causes upregulation of proatherogenic genes, downregulation of antiatherogenic genes, endothelial dysfunction, and rapid atherosclerosis in 2 wk in a p47(phox)-dependent manner and advanced lesions by 4 wk. We found that partial ligation results in endothelial dysfunction, rapid atherosclerosis, and advanced lesion development in a physiologically relevant model of disturbed flow. It also allows for easy and rapid intimal RNA isolation. This novel model and method could be used for genome-wide studies to determine molecular mechanisms underlying flow-dependent regulation of vascular biology and diseases.
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Affiliation(s)
- Douglas Nam
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, USA
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Tressel SL, Kim H, Ni CW, Chang K, Velasquez-Castano JC, Taylor WR, Yoon YS, Jo H. Angiopoietin-2 stimulates blood flow recovery after femoral artery occlusion by inducing inflammation and arteriogenesis. Arterioscler Thromb Vasc Biol 2008; 28:1989-95. [PMID: 18772493 DOI: 10.1161/atvbaha.108.175463] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Recently, we have shown that shear stress regulates the angiogenic potential of endothelial cells in vitro by an Angiopoietin-2 (Ang2)-dependent mechanism; however its pathophysiological significance in vivo was not clear. We hypothesized that Ang2 plays an important role in blood flow recovery after arterial occlusion in vivo by regulating angiogenesis and arteriogenesis. METHODS AND RESULTS C57Bl/6J mice underwent femoral artery ligation and were injected with a specific Ang2 inhibitor, L1-10, or vehicle for 10 days. Ang2 mRNA was upregulated at day 2, and Ang2 protein was upregulated at day 2, 5, and 7 in the ligated hindlimb. L1-10 treatment significantly blunted blood flow recovery. L1-10 decreased smooth muscle cell coverage of neovessels without affecting capillary density, suggesting a specific role for Ang2 in arteriogenesis. Mechanistically, L1-10 decreased expression of intercellular and vascular cell adhesion molecules as well as infiltrating monocytes/macrophages in the ischemic tissue. Although L1-10 had no effect on the number of CD11b+ cells (monocytes/macrophages) mobilized in the bone marrow, it maintained elevated numbers of circulating CD11b+ cells in the peripheral blood. CONCLUSIONS These results suggest that Ang2 induced in ischemic tissue plays a critical role in blood flow recovery by stimulating inflammation and arteriogenesis.
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Affiliation(s)
- Sarah L Tressel
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA 30322, USA
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20
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Tsai YC, Hsieh HJ, Liao F, Ni CW, Chao YJ, Hsieh CY, Wang DL. Laminar flow attenuates interferon-induced inflammatory responses in endothelial cells. Cardiovasc Res 2007; 74:497-505. [PMID: 17383622 DOI: 10.1016/j.cardiores.2007.02.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 01/19/2007] [Accepted: 02/27/2007] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Atherosclerosis is a chronic disease that involves inflammation, in which cytokines, including interferon-gamma (IFNgamma), participate. Endothelial cells (ECs) exposed to IFNgamma increase the expression of CXC chemokines. ECs subjected to laminar flow (LF) are atheroprotective, despite an unclear mechanism. This study was conducted to analyze whether ECs under LF were protected from IFNgamma-induced responses. METHODS IFNgamma-treated human umbilical cord ECs were subjected to LF in a well-defined flow chamber system. IFNgamma-induced STAT1 activation and downstream target genes were examined. RESULTS ECs exposed to IFNgamma triggered STAT1 activation via the phosphorylation of Tyr701 and Ser727 in STAT1. ECs exposed to LF alone did not activate STAT1. LF exposure of IFNgamma-treated ECs significantly attenuated IFNgamma-induced Tyr701 phosphorylation in a shear-force- and time-dependent manner, whereas Ser727 phosphorylation was unaffected. Consistently, LF inhibited IFNgamma-induced STAT1 binding to DNA. ECs treated with IFNgamma induced the expression of three T-cell-specific CXC chemokines (CXCL9, CXCL10 and CXCL11) as well as CIITA, a transcriptional regulator of major histocompatibility complex class II (MHCII). Consistently, LF exposure of IFNgamma-treated ECs reduced the expression of CXC chemokines and CIITA. CONCLUSIONS LF attenuates IFNgamma-induced responses via the suppression of STAT1 activation. Inhibition by LF of the interferon-induced ECs' response may explain some aspects of LF's atheroprotective effects on the endothelium.
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Affiliation(s)
- Yu-Chih Tsai
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
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Wung BS, Ni CW, Wang DL. ICAM-1 induction by TNFalpha and IL-6 is mediated by distinct pathways via Rac in endothelial cells. J Biomed Sci 2005; 12:91-101. [PMID: 15864742 DOI: 10.1007/s11373-004-8170-z] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Accepted: 10/08/2004] [Indexed: 10/25/2022] Open
Abstract
Atherogenesis is a chronic inflammatory response and intercellular adhesion molecule (ICAM-1) induced by cytokines plays a role in this event. In this study, the molecular mechanisms of tumor neurosis factor alpha (TNFalpha)- and IL-6-induced ICAM-1 gene expression in endothelial cells (ECs) were examined. ECs infected with adenovirus carrying the dominant negative mutant of Rac (Ad-RacN17) exhibited inhibition in both TNFalpha- and IL-6-induced ICAM-1 expression. Consistently, ECs transfected with RacN17 inhibited both TNFalpha- and IL-6-induced ICAM-1 promoter activities. Functional analysis of ICAM-1 promoter, however, indicated that the cis-acting elements in response to TNFalpha and IL-6 are different. The NFkappaB binding site in the ICAM-1 promoter region was crucial for TNFalpha-induced ICAM-1 expression but not for the induction by IL-6. ECs infected with Ad-RacN17 attenuated the TNFalpha-induced NFkappaB binding activity. In contrast, IL-6 activated a transcriptional factor, signal transducer and activator of transcription-3 (Stat3) via the phosphorylation of Tyr705 at Stat3. ECs transfected with the dominant negative mutant of Stat3 (Stat3F) demonstrated that Stat3 was required for IL-6-induced ICAM-1 gene expression. Interestingly, the phosphorylation of Tyr705 and Ser727 in Stat3 was greatly inhibited in IL-6-treated ECs previously infected with Ad-RacN17. Our data strongly indicated that ICAM-1 gene induction by TNFalpha and IL-6 is mediated mainly via NFkappaB and Stat3, respectively and Rac1 appears to play a central role in modulating cytokine-induced ICAM-1 expression in ECs.
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Affiliation(s)
- B S Wung
- Department of Applied Microbiology, National Chiayi University, Chiayi, Taiwan
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Ni CW, Hsieh HJ, Chao YJ, Wang DL. Interleukin-6-induced JAK2/STAT3 signaling pathway in endothelial cells is suppressed by hemodynamic flow. Am J Physiol Cell Physiol 2004; 287:C771-80. [PMID: 15151905 DOI: 10.1152/ajpcell.00532.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial cells (ECs) are constantly exposed to shear stress, the action of which triggers signaling pathways and cellular responses. During inflammation, cytokines such as IL-6 increase in plasma. In this study, we examined the effects of steady flow on IL-6-induced endothelial responses. ECs exposed to IL-6 exhibited STAT3 activation via phosphorylation of Tyr705. However, when ECs were subjected to shear stress, shear force-dependent suppression of IL-6-induced STAT3 phosphorylation was observed. IL-6 treatment increased the phosphorylation of JAK2, an upstream activator of STAT3. Consistently, shear stress significantly reduced IL-6-induced JAK2 activation. Pretreatment of ECs with an inhibitor of MEK1 did not alter this suppression by shear stress, indicating that extracellular signal-regulated kinase (ERK1/2) was not involved. However, pretreatment of ECs with an endothelial nitric oxide synthase inhibitor (nitro-l-arginine methyl ester) attenuated this inhibitory effect of shear stress on STAT3 phosphorylation. Shear stress-treated ECs displayed decreased nuclear transmigration of STAT3 and reduced STAT3 binding to DNA. Intriguingly, ECs exposed to IL-6 entered the cell cycle, as evidenced by increasing G2/M phase, and shear stress to these ECs significantly reduced IL-6-induced cell cycle progression. STAT3-mediated IL-6-induced cell cycle was confirmed by the inhibition of the cell cycle in ECs infected with adenovirus carrying the inactive mutant of STAT3. Our study clearly shows that shear stress exerts its inhibitory regulation by suppressing the IL-6-induced JAK2/STAT3 signaling pathway and thus inhibits IL-6-induced EC proliferation. This shear force-dependent inhibition of IL-6-induced JAK2/STAT3 activation provides new insights into the vasoprotective effects of steady flow on ECs against cytokine-induced responses.
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Affiliation(s)
- Chih-Wen Ni
- Cardiovascular Division, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan 11529
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Ni CW, Wang DL, Lien SC, Cheng JJ, Chao YJ, Hsieh HJ. Activation of PKC-epsilon and ERK1/2 participates in shear-induced endothelial MCP-1 expression that is repressed by nitric oxide. J Cell Physiol 2003; 195:428-34. [PMID: 12704652 DOI: 10.1002/jcp.10259] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Vascular endothelial cells (ECs) continuously experience hemodynamic shear stress generated from blood flow. Previous studies have demonstrated that shear stress modulates monocyte chemotactic protein-1 (MCP-1) expression in ECs. This study explored the roles of protein kinase C (PKC), extracellular signal-regulated protein kinase (ERK1/2), and nitric oxide (NO) in sheared-induced MCP-1 expression in ECs. The activation of PKC-alpha and PKC-epsilon isoforms was observed in ECs exposed to shear stress. The use of an inhibitor (calphostin C) to PKC-alpha and PKC-epsilon decreased ERK1/2 activation and MCP-1 induction by shear, whereas an inhibitor (Go6976) to PKC-alpha did not affect ERK1/2 activation or MCP-1 induction. Inhibition of ERK1/2 activation by PD98059 blocked MCP-1 induction. Transfection of ECs with an antisense to PKC-epsilon abolished the shear inducibility of MCP-1 promoter. These results demonstrate that PKC-epsilon and ERK1/2 participate in shear-induced MCP-1 expression. We also examined the regulatory role of NO in MCP-1 expression. An NO donor (NOC18) suppressed shear-induced activation of PKC-epsilon and ERK1/2, and also repressed MCP-1 induction. Consistently, overexpression of endothelial nitric oxide synthase (eNOS) to enhance the endogenous generation of NO in ECs decreased the activation of PKC-epsilon and ERK1/2, and also inhibited MCP-1 expression. Taken together, these findings suggest that PKC-epsilon and ERK1/2 are critical in the signaling pathway(s) leading to the MCP-1 expression induced by shear stress. Additionally, this study indicates that NO, by repressing PKC-epsilon activity and ERK pathway activation, attenuates shear-induced MCP-1 expression.
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Affiliation(s)
- Chih-Wen Ni
- Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan
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Abstract
Vascular endothelial cells (ECs) are constantly exposed to flow-induced shear stress. Shear stress is known to induce signaling cascades, including the extracellular signal-regulated protein kinase (ERK) pathway. STAT3 transcription factor plays a key role in cytokine stimulation. Recent studies indicate that STAT3 is involved in growth factor-induced cell cycle. In the present study, we have examined STAT3 activation of ECs under conditions of shear flow. Bovine aortic ECs cultured with serum at static state show a serum concentration-dependent phosphorylation at Tyr-705 of STAT3, whereas there is a constant basal phosphorylation at Ser-727. In ECs subjected to shear flow, a shear dose-dependent phosphorylation of Ser-727 and ERK1/2 was observed. In contrast, a concomitantly shear dose-dependent inhibition of phosphorylation at Tyr-705 was exhibited. Shear stress on ECs increased the association of ERK1/2 to STAT3. ECs treated with MEK inhibitor (U0126 or PD98059) consistently and significantly reduced the shear-induced ERK1/2 and Ser-727 phosphorylation, indicating that ERK1/2 is upstream of Ser-727 phosphorylation. Interestingly, shear-induced inhibition in Tyr-705 phosphorylation was abolished in these same inhibitor-treated ECs. Similarly, ECs transfected with a dominant positive mutant of MEK1 enhanced the phosphorylation of Ser-727 with the attenuation of the Tyr-705 phosphorylation. In contrast, when ECs were transfected with dominant positive mutant of MEKK1, JNK upstream, no change in the phosphorylation of Ser-727 and Tyr-705 was observed. These results indicate that shear flow induces the phosphorylation of Ser-727 via ERK1/2 pathway, and this Ser-727 phosphorylation inhibits Tyr-705 phosphorylation in STAT3. As a result, shear flow reduced the translocation of STAT3 into nucleus. This study shows for the first time that shear flow may play a significant role by attenuating STAT3 activation and thus may reduce inflammatory responses and/or serum-induced endothelial proliferation.
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Affiliation(s)
- Chih-Wen Ni
- Cardiovascular Division, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan 11529
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