Vascular Biology |
From the Department of Cardiovascular Medicine (M.S., S.S., Y.H., R.N.) and the Department of Geriatric Medicine (M.Y., Y.O.), University of Tokyo, Graduate School of Medicine, Tokyo, Japan.
Correspondence to Dr Masataka Sata, Department of Cardiovascular Medicine, University of Tokyo, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. E-mail sata-2im{at}h.u-tokyo.ac.jp
| Abstract |
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Key Words: Fas apoptosis balloon injury smooth muscle cells intima
| Introduction |
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Fas is a death receptor that transmits apoptosis-inducing signals when activated by its ligand (FasL).16 The Fas/FasL system was first identified in the immune system.17,18 However, at present, there is a large body of evidence indicating that the Fas/FasL interaction controls cell death in a wide variety of cell types under physiological and pathological conditions.17,1924 Cultured VSMCs express abundant Fas on their surface and undergo apoptosis when stimulated by membrane-bound FasL.12,25 Fas was found to be expressed on apoptotic cells in atherosclerotic lesions,7 and it has been proposed that Fas-mediated apoptosis might be involved in the pathogenesis of atherosclerosis.7,26,27
For a better understanding of the pathogenesis of vascular diseases, genetically modified mice have been used.28 Significant neointima-like hyperplasia was noted in several models of vascular injury prepared according to the perivascular approach.2931 However, in no mouse model was medial cell apoptosis (which plays a pivotal role in vascular remodeling after balloon angioplasty) induced rapidly after the injury.3,4,11 We recently developed a new mouse model of vascular injury, which may resemble the balloon angioplasty model.32 This vascular injury results in medial smooth muscle cell apoptosis after 1 to 7 hours and marked enlargement of the lumen, followed by robust VSMC proliferation and an intimal lesion.32 The neointima continues to grow for 3 weeks; thereafter, no significant change in the size of the neointima is observed. Neointimal hyperplasia is exclusively composed of
-smooth muscle actinpositive cells.32
In the present study, we took advantage of mouse genetics to study the potential involvement of the Fas/FasL system in acute and chronic VSMC apoptosis and in the development of vascular lesions. We induced endovascular injury in wild-type, gld (Fas ligand-/-), and lpr (Fas-/-) mice. There was no significant difference in the number of acute and chronic apoptotic cells or in the size of neointimal hyperplasia among the 3 groups. These results suggest the existence of a Fas-independent pathway that mediates acute and chronic smooth muscle cell apoptosis, at least in response to mechanical overexpansion of the artery.
| Methods |
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Mouse Femoral Injury Model
Transluminal mechanical injury of the femoral artery was induced by inserting a large wire, as previously described.32 A copy of the tutorial video of the surgical procedure can be obtained by request to M.S., or the video can be viewed online at http://plaza.umin.ac.jp/
msata/. Briefly, either the left or right femoral artery was exposed by blunt dissection. The femoral artery and vein were looped together proximally and distally with 6-0 silk suture (Natsume Co) for temporary vascular control during the procedure. A straight spring wire (0.38-mm diameter, No. C-SF-15-15, Cook) was carefully inserted into the femoral artery toward the iliac artery via a small branch between the rectus femoris and vastus medialis muscles. The wire was left in place for 1 minute to denude and dilate the artery. Then, the wire was removed, and the silk suture at the proximal portion of the muscular branch artery was secured. Blood flow in the femoral artery was restored by releasing the sutures placed in the proximal and distal femoral portions. The skin incision was closed with a 5-0 silk suture (Natsume Co). The mice were euthanized by intraperitoneal administration of an overdose of Nembutal. Soon after they died, the mice were perfused at a constant pressure via the left ventricle with 0.9% NaCl solution, followed by perfusion fixation in freshly depolymerized 4% paraformaldehyde in PBS (pH 7.4). The femoral artery was carefully excised, further fixed in 4% paraformaldehyde overnight at 4°C, and embedded in paraffin.
Injection of Anti-Fas Antibody
Agonistic anti-Fas antibody (clone Jo2) was purchased from PharMingen.33 The antibody was diluted in PBS and administered intravenously to 8-week-old male C3H/HeJ and C3H-lpr (Fas-/-) mice through the tail vein at 0.5 µg/g. The liver tissues were removed at death, fixed with 4% paraformaldehyde in PBS (pH 7.4), and embedded in paraffin. Three hours after the injection, surviving mice were euthanized by intraperitoneal administration of an overdose of Nembutal, after which the liver tissues were excised. Paraffin-embedded sections were stained with hematoxylin and eosin.
Morphometric Analysis
Cross sections (5 µm) were deparaffinized, stained with hematoxylin and eosin, and mounted with mounting media (Mount Quick, Daido). The image was digitized by a Fujix Digital Camera (HC-300/OL, Fujifilm Co) on a Provis AX80 microscope (Olympus). Morphometric analysis was performed by using software for image analysis (LIA32 for Windows 95, version 0.372, Kazukiyo Yamamoto) on a PC computer (Presario 2295, Compaq). All data are expressed as the mean±SEM.
Staining by TdT-Mediated dUTP Nick End-Labeling
The 4% paraformaldehydefixed sections (5 µm) were deparaffinized and rehydrated. The tissue was then treated with 20 µg/mL proteinase K for 30 minutes. Terminal deoxynucleotidyl transferase (TdT) enzyme and fluorescein-dUTP were added to the tissue sections in accordance with the instructions provided by the manufacturer (In Situ Death Detection Kit, Roche Molecular Biochemicals). Nuclei were counterstained with Hoechst 33258 (Sigma Chemical Co) and mounted with Vectashield mounting media (Vector Laboratories, Inc). Specimens were examined and photographed by using a Provis AX80 microscope (Olympus) equipped with an epifluorescence optical lens.
Immunohistochemistry
Paraffin-embedded sections (5 µm thick) were deparaffinized and blocked with 1% rabbit serum. Endothelial cells, T lymphocytes, polymorphonuclear cells, and macrophages were revealed by immunostaining with anti-CD31 antibody (clone MEC13.3, PharMingen), anti-CD3
hamster monoclonal antibody (Santa Cruz Biotechnology), anti-CD11b monoclonal antibody (clone M1/70, Serotec), and anti-F4/80 monoclonal antibody (clone A3-1, Serotec), respectively, followed by the avidin-biotin complex technique and Vector Red substrate (Vector Laboratories, Inc). Smooth muscle cells were identified by immunostaining with an alkaline phosphataseconjugated monoclonal antibody to
-smooth muscle actin (clone 1A4, Sigma). Sections were counterstained with hematoxylin.
Statistical Analysis
All results are expressed as the mean±SEM The means were statistically compared by ANOVA, followed by the Student t test. A value of P<0.05 was considered statistically significant.
| Results |
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At 4 hours after injury, a similar frequency of apoptosis was detected in wild-type, gld (FasL-/-), and lpr (Fas-/-) mice. There was no significant difference in the number of apoptotic cells among the 3 groups of mice (Figure 1B), indicating that the Fas/FasL system was not involved in VSMC apoptosis induced by vascular injury.
Development of Lesions in FasL- or Fas-Deficient Mice
Four weeks after the injury, a concentric neointimal lesion was found where the large wire had been placed in all mice examined (Figure 2).32 FasL- and Fas-deficient mice developed lesions similar to those developed by wild-type mice (n=6 per group, Figure 2). There was no significant difference in the degree of the neointima (intima/media area ratio was as follows: wild type 1.4 ±0.3, gld 1.0±0.2, and lpr 1.3±0.2) or in the vessel size (circumference of external elastic lamina was as follows: wild type 1.00±0.08 mm, gld 1.07±0.08 mm, and lpr 1.07±0.05 mm) among the 3 groups. .
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The neointima was exclusively composed of smooth muscle cells in wild-type, gld, and lpr mice, as determined by immunostaining for
-smooth muscle actin (Figure 3). In all mice, the luminal side of the intima was almost completely reendothelialized at 4 weeks, as determined by anti-CD31 staining (Figure 3). No capillary formation was detected in the intima, excluding the possibility that neointimal formation had resulted from recanalized thrombosis. Macrophages were detected in the adventitia and occasionally in the intima, as determined by immunostaining for F4/80. Macrophage accumulation in the adventitia was more prominent in gld and lpr mice than in wild-type mice (Figure 3). However, we observed no macrophage infiltration in the media. Polymorphonuclear cells and T lymphocytes were seldom detected in the intima (data not shown).
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Chronic VSMC Apoptosis in the Vascular Lesion in the Absence of FasL/Fas Interaction
TUNEL staining revealed that at 4 weeks after injury, a small fraction of the VSMCs was undergoing apoptotic cell death in the neointima as well as in the media (Figure 4). The frequency of apoptosis in the chronic lesions was markedly smaller than that observed 4 hours after the wire injury. The number of apoptotic cells in gld (FasL-/-) or lpr (Fas-/-) mice was not significantly different from that found in wild-type mice, indicating that a Fas-independent pathway mediates VSMC apoptosis in the vascular lesions induced by acute mechanical injury (Table). .
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Lack of Fas-Mediated Apoptosis in Fas-Deficient Mice
To demonstrate lack of Fas-mediated apoptosis in lpr mice, wild-type mice and lpr mice were challenged with an agonistic anti-Fas antibody.33 Consistent with the results of a previous report,33 the present study found that intravenous injection of the anti-Fas antibody killed all wild-type mice (n=3) within 3 hours, whereas no lpr mouse died. Histological examination revealed fulminant liver injury with diffuse hemorrhage and massive apoptosis of hepatocytes in the liver of wild-type mice, whereas the liver of the lpr mice appeared intact (data not shown). These findings demonstrate that the lpr mice used in the present study were in fact deficient in Fas-mediated apoptosis.
| Discussion |
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Numerous studies have shown that Fas is implicated in VSMC apoptosis in vascular lesions.7,26,27,34 VSMCs abundantly express Fas,12,25 whose expression is regulated by cytokines7,25 and a tumor suppressor gene, p53.34 Fas expression was also identified on apoptotic VSMCs in human atherosclerotic plaques.7,8 Our results indicate the existence of other molecular pathways that may mediate acute and chronic VSMC apoptosis, at least in lesions induced by the mechanical overexpansion of the artery.
It has been suggested that Fas-mediated signaling contributes to inflammatory responses in vessel walls and, therefore, may promote atherogenesis.35,36 It has been demonstrated that the activation of Fas in peritoneal exudate cells provokes inflammatory responses by stimulating the release of interleukin-1.35 Overexpression of the Fas-associated death domain protein in VSMCs seeded within balloon-injured rat carotid arteries has been shown to result in chemokine expression and the recruitment of macrophages.36 In the present study, we did not observe any attenuation of inflammatory responses in mice deficient in FasL or Fas after the vascular injury. On the contrary, the accumulation of macrophages in the adventitia was more pronounced in FasL-/- and Fas-/- mice. Moreover, it is well known that Fas-deficient mice spontaneously develop generalized degenerative vascular lesions and necrotizing arteritis, which are preceded by infiltration of mononuclear cells and granulocytes.37 More recently, it has been shown that FasL-deficient mice display enhanced macrophage and T-cell infiltration and intima hyperplasia during vascular remodeling in flow-restricted vessels with an intact endothelium.30,38 These data do not support the hypothesis that the Fas/FasL system plays a major role in promoting inflammatory responses in the vessel wall after acute mechanical injury.
Furthermore, it has been suggested that Fas may promote VSMC proliferation in vascular lesions.7,8 Recent studies have demonstrated the role of Fas in the transduction of growth-promoting signals in T cells,39 cardiomyocytes,40 fibroblasts,41 and hepatocytes.42 Schneider et al43 have demonstrated that adenovirus-mediated overexpression of exogenous FasL facilitates VSMC accumulation in hypercholesterolemic rabbits, and they have suggested that vascular expression of FasL may contribute to the progression of atherosclerosis.43 In the present study, mice deficient in Fas or FasL developed neointima hyperplasia similar to that observed in wild-type mice, excluding the possibility that Fas/FasL signaling mediated the VSMC proliferation in the vascular lesions. Moreover, we previously reported that overexpression of FasL induced massive VSMC apoptosis in vitro25 and that adenovirus-mediated gene delivery of FasL into the balloon-injured artery potently limited the size of the lesion.12,14 Taken together, the present findings indicate that endogenous Fas/FasL interaction is not a major determinant for VSMC proliferation, at least in response to mechanical overexpansion of the artery.
In conclusion, the present results indicate that VSMC apoptosis after acute mechanical injury can occur independently of the Fas-death pathway. Fas-independent pathways appear to exist for these phenomena, although further study is required to evaluate the role of the Fas/FasL system in apoptosis, proliferation, and inflammation in other types of vascular diseases, such as atherosclerosis and transplantation-associated arteriosclerosis.
| Acknowledgments |
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Received July 27, 2001; accepted September 7, 2001.
| References |
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2. Han DKM, Haudenschild CC, Hong MK, Tinkle BT, Leon MB, Liau G. Evidence for apoptosis in human atherogenesis and in a rat vascular injury model. Am J Pathol. 1995; 147: 267277.[Abstract]
3.
Perlman H, Maillard L, Krasinski K, Walsh K, Evidence for the rapid onset of apoptosis in medial smooth muscle cells following balloon injury. Circulation. 1997; 95: 981987.
4.
Pollman MJ, Hall JL, Gibbons GH, Determinants of vascular smooth muscle cell apoptosis after balloon angioplasty injury. Circ Res. 1999; 84: 113121.
5.
Walsh K, Isner JM. Apoptosis in inflammatory-fibroproliferative disorders of the vessel wall. Cardiovasc Res. 2000; 45: 756765.
6.
Walsh K, Smith RC, Kim HS. Vascular cell apoptosis in remodeling, restenosis, and plaque rupture. Circ Res. 2000; 87: 184188.
7.
Geng Y-J, Henderson LE, Levesque EB, Muszynski M, Libby P. Fas is expressed in human atherosclerotic intima and promotes apoptosis of cytokine-primed human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol. 1997; 17: 22002208.
8. Cai W, Devaux B, Schaper W, Schaper J. The role of Fas/APO 1 and apoptosis in the development of human atherosclerotic lesions. Atherosclerosis. 1997; 131: 177186.[Medline] [Order article via Infotrieve]
9. Fukuo K, Inoue T, Morimoto S, Nakahashi T, Yasuda O, Kitano S, Sasada R, Ogihara T. Nitric oxide mediates cytotoxicity and basic fibroblast growth factor release in cultured vascular smooth muscle cells: a possible mechanism of neovascularization in atherosclerotic plaques. J Clin Invest. 1995; 95: 669676.[Medline] [Order article via Infotrieve]
10. Fukuo K, Nakahashi T, Nomura S, Hata S, Suhara T, Shimizu M, Tamatani M, Morimoto S, Kitamura Y, Ogihara T. Possible participation of Fas-mediated apoptosis in the mechanism of atherosclerosis. Gerontology. 1997; 43: 3542.[Medline] [Order article via Infotrieve]
11. Rivard A, Luo Z, Perlman H, Fabre J, Nguyen T, Walsh K. Early cell loss following angioplasty results in a disproportionate decrease in gene transfer to the vessel wall. Hum Gene Ther. 1999; 10: 711721.[Medline] [Order article via Infotrieve]
12.
Sata M, Perlman H, Muruve DA, Silver M, Ikebe M, Libermann TA, Oettgen P, Walsh K. Fas ligand gene transfer to the vessel wall inhibits neointima formation and overrides the adenovirus-mediated T cell response. Proc Natl Acad Sci U S A. 1998; 95: 12131217.
13.
Perlman H, Sata M, Krasinski K, Dorai T, Buttyan R, Walsh K. Adenovirus-encoded hammerhead ribozyme to Bcl-2 inhibits neointimal hyperplasia and induces vascular smooth muscle cell apoptosis. Cardiovasc Res. 2000; 45: 570578.
14.
Luo Z, Sata M, Nguyen T, Kaplan JM, Akita GY, Walsh K. Adenovirus-mediated delivery of Fas ligand inhibits intimal hyperplasia after balloon injury in immunologically primed animals. Circulation. 1999; 99: 17761779.
15. Pollman MJ, Hall JL, Mann MJ, Zhang L, Gibbons GH. Inhibition of neointimal cell bcl-x expression induces apoptosis and regression of vascular disease. Nat Med. 1998; 4: 222227.[Medline] [Order article via Infotrieve]
16.
Nagata S, Golstein P. The Fas death factor. Science. 1995; 267: 14491456.
17. Nagata S. Apoptosis by death factor. Cell. 1997; 88: 355365.[Medline] [Order article via Infotrieve]
18.
Klas C, Debatin K-M, Jonker RR, Krammer PH. Activation interferes with the APO-1 pathway in mature human T cells. Int Immunol. 1993; 5: 625630.
19. Muller M, Strand S, Hug H, Heinemann E-M, Walczak H, Hofmann WJ, Stremmel W, Krammer PH, Galle PR. Drug-induced apoptosis in hepatoma cells is mediated by the CD95 (APO-1/Fas) receptor/ligand system and involves activation of wild-type p53. J Clin Invest. 1997; 99: 403413.[Medline] [Order article via Infotrieve]
20.
Hueber A-O, Zornig M, Lyon D, Suda T, Nagata S, Evan GI. Requirement for the CD95 receptor-ligand pathway in c-Myc-induced apoptosis. Science. 1997; 278: 13051309.
21. Friesen C, Herr I, Krammer H, Debatin K-M. Involvement of the CD95 (Apo-1/Fas) receptor/ligand system in drug-induced apoptosis in leukemia cells. Nat Med. 1996; 2: 574577.[Medline] [Order article via Infotrieve]
22.
Reap EA, Roof K, Maynor K, Borrero M, Booker J, Cohen P. Radiation and stress-induced apoptosis: a role for Fas/Fas ligand interaction. Proc Natl Acad Sci U S A. 1997; 94: 57505755.
23.
Rehemtulla A, Hamilton CA, Chinnaiyan AM, Dixit VM. Ultraviolet radiation-induced apoptosis is mediated by activation of CD-95 (Fas/APO-1). J Biol Chem. 1997; 272: 2578325786.
24. Sata M, Walsh K. Oxidized LDL activates Fas-mediated endothelial cell apoptosis. J Clin Invest. 1998; 102: 16821689.[Medline] [Order article via Infotrieve]
25.
Sata M, Suhara T, Walsh K. Vascular endothelial cells and smooth muscle cells differ in expression of Fas and Fas ligand and in sensitivity to Fas ligandinduced cell death: implications for vascular disease and therapy. Arterioscler Thromb Vasc Biol. 2000; 20: 309316.
26.
Fukuo K, Hata S, Suhara T, Nakahashi T, Shinto Y, Tsujimoto Y, Morimoto S, Ogihara T. Nitric oxide induces upregulation of Fas and apoptosis in vascular smooth muscle. Hypertension. 1996; 27: 823826.
27. Han DKM, Wright ME, Dixit VM, Pruitt R, Soe HS, Lynch DH, Schwartz SM. Evidence for escape of apoptosis by loss of FAS in atherosclerotic plaque smooth muscle cells. Circulation. 1996; 94 (suppl I): I-397. Abstract.
28.
Faraci FM, Sigmund CD. Vascular biology in genetically altered mice: smaller vessels, bigger insight. Circ Res. 1999; 85: 12141225.
29. Carmeliet P, Moons L, Stassen J-M, Mol MD, Bouche A, van den Oord JJ, Kockx M, Collen D. Vascular wound healing and neointima formation induced by perivascular electric injury in mice. Am J Pathol. 1997; 150: 761776.[Abstract]
30.
Kumar A, Lindner V. Remodeling with neointima formation in the mouse carotid artery after cessation of blood flow. Arterioscler Thromb Vasc Biol. 1997; 17: 22382244.
31. Moroi M, Zhang L, Yasuda T, Virmani R, Gold HK, Fishman MC, Huang PL. Interaction of genetic deficiency of endothelial nitric oxide, gender, and pregnancy in vascular response to injury in mice. J Clin Invest. 1998; 101: 12251232.[Medline] [Order article via Infotrieve]
32. Sata M, Maejima Y, Adachi F, Fukino K, Saiura A, Sugiura S, Aoyagi T, Imai Y, Kurihara H, Kimura K, et al. A mouse model of vascular injury that induces rapid onset of medial cell apoptosis followed by reproducible neointimal hyperplasia. J Mol Cell Cardiol. 2000; 32: 20972104.[Medline] [Order article via Infotrieve]
33. Ogasawara J, Watanabe-Fukunaga R, Adachi M, Matsuzawa A, Kasugai T, Kitamura Y, Itoh N, Suda T, Nagata S. Lethal effect of the anti-Fas antibody in mice. Nature. 1993; 364: 806809.[Medline] [Order article via Infotrieve]
34.
Bennett M, Macdonald K, Chan SW, Luzio JP, Simari R, Weissberg P. Cell surface trafficking of Fas: a rapid mechanism of p53-mediated apoptosis. Science. 1998; 282: 290293.
35. Miwa K, Asano M, Horai R, Iwakura Y, Nagata S, Suda T. Caspase 1-independent IL-1beta release and inflammation induced by the apoptosis inducer Fas ligand. Nat Med. 1998; 4: 12871792.[Medline] [Order article via Infotrieve]
36. Schaub FJ, Han DK, Liles WC, Adams LD, Coats SA, Ramachandran RK, Seifert RA, Schwartz SM, Bowen-Pope DF. Fas/FADD-mediated activation of a specific program of inflammatory gene expression in vascular smooth muscle cells. Nat Med;. 2000; 6: 790796.[Medline] [Order article via Infotrieve]
37.
Hewicker M, Trautwein G. Sequential study of vasculitis in MRL mice. Lab Anim. 1987; 21: 335341.
38. Sata M, Walsh K. Fas ligand-deficient mice display enhanced leukocyte infiltration and intima hyperplasia in flow restricted vessels. J Mol Cell Cardiol. 2000; 32: 13951400.[Medline] [Order article via Infotrieve]
39.
Desbarats J, Wade T, Wade WF, Newell MK. Dichotomy between naive and memory CD4(+) T cell responses to Fas engagement. Proc Natl Acad Sci U S A. 1999; 96: 81048109.
40. Nelson DP, Setser E, Hall DG, Schwartz SM, Hewitt T, Klevitsky R, Osinska H, Bellgrau D, Duke RC, Robbins J. Proinflammatory consequences of transgenic fas ligand expression in the heart. J Clin Invest. 2000; 105: 11991208.[Medline] [Order article via Infotrieve]
41. Freiberg RA, Spencer DM, Choate KA, Duh HJ, Schreiber SL, Crabtree GR, Khavari PA. Fas signal transduction triggers either proliferation or apoptosis in human fibroblasts. J Invest Dermatol. 1997; 108: 215219.[Medline] [Order article via Infotrieve]
42. Desbarats J, Newell MK. Fas engagement accelerates liver regeneration after partial hepatectomy. Nat Med. 2000; 6: 920923.[Medline] [Order article via Infotrieve]
43.
Schneider DB, Vassalli G, Wen S, Driscoll RM, Sassani AB, DeYoung MB, Linnemann R, Virmani R, Dichek DA. Expression of Fas ligand in arteries of hypercholesterolemic rabbits accelerates atherosclerotic lesion formation. Arterioscler Thromb Vasc Biol. 2000; 20: 298308.
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