The Complement C3a−C3aR Axis Promotes Development of Thoracic Aortic Dissection via Regulation of MMP2 Expression This information is current as Weihong Ren, Yan Liu, Xuerui Wang, Chunmei Piao, of September 24, 2021. Youcai Ma, Shulan Qiu, Lixin Jia, Boya Chen, Yuan Wang, Wenjian Jiang, Shuai Zheng, Chang Liu, Nan Dai, Feng Lan, Hongjia Zhang, Wen-chao Song and Jie Du J Immunol 2018; 200:1829-1838; Prepublished online 24 January 2018; Downloaded from doi: 10.4049/jimmunol.1601386 http://www.jimmunol.org/content/200/5/1829 Supplementary http://www.jimmunol.org/content/suppl/2018/01/24/jimmunol.160138 http://www.jimmunol.org/ Material 6.DCSupplemental References This article cites 54 articles, 21 of which you can access for free at: http://www.jimmunol.org/content/200/5/1829.full#ref-list-1 Why The JI? Submit online. by guest on September 24, 2021 • Rapid Reviews! 30 days* from submission to initial decision • No Triage! 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The Journal of Immunology The Complement C3a–C3aR Axis Promotes Development of Thoracic Aortic Dissection via Regulation of MMP2 Expression Weihong Ren,*,†,1 Yan Liu,*,1 Xuerui Wang,‡,1 Chunmei Piao,* Youcai Ma,* Shulan Qiu,* Lixin Jia,* Boya Chen,* Yuan Wang,* Wenjian Jiang,* Shuai Zheng,* Chang Liu,* Nan Dai,* Feng Lan,* Hongjia Zhang,* Wen-chao Song,x and Jie Du* Thoracic aortic dissection (TAD), once ruptured, is devastating to patients, and no effective pharmaceutical therapy is available. Anaphylatoxins released by complement activation are involved in a variety of diseases. However, the role of the complement Downloaded from system in TAD is unknown. We found that plasma levels of C3a, C4a, and C5a were significantly increased in patients with TAD. Elevated circulating C3a levels were also detected in the developmental process of mouse TAD, which was induced by b-amino- propionitrile monofumarate (BAPN) treatment, with enhanced expression of C1q and properdin in mouse dissected aortas. These findings indicated activation of classical and alternative complement pathways. Further, expression of C3aR was obviously increased in smooth muscle cells of human and mouse dissected aortas, and knockout of C3aR notably inhibited BAPN- induced formation and rupture of TAD in mice. C3aR antagonist administered pre- and post-BAPN treatment attenuated the http://www.jimmunol.org/ development of TAD. We found that C3aR knockout decreased matrix metalloproteinase 2 (MMP2) expression in BAPN-treated mice. Additionally, recombinant C3a stimulation enhanced MMP2 expression and activation in smooth muscle cells that were subjected to mechanical stretch. Finally, we generated MMP2-knockdown mice by in vivo MMP2 short hairpin RNA delivery using recombinant adeno-associated virus and found that MMP2 deficiency significantly reduced the formation of TAD. Therefore, our study suggests that the C3a–C3aR axis contributes to the development of TAD via regulation of MMP2 expression. Targeting the C3a–C3aR axis may represent a strategy for inhibiting the formation of TAD. The Journal of Immunology, 2018, 200: 1829–1838. horacic aortic dissection (TAD) is the most common acute space of the thoracic aorta, leading to separation of the layers thoracic aortic syndrome, with high morbidity and mor- within the aortic wall, which characterizes TAD. Microscopically, by guest on September 24, 2021 T tality. At the macroscopic level, blood enters the medial the pathology of TAD shows medial degeneration in the form of smooth muscle cell (SMC) loss and elastic fiber fragmentation or depletion (1–3). Clinically, the risk factors for TAD are divided *Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-Related Car- into two categories: conditions that increase aortic wall stress and diovascular Diseases, Ministry of Education, Beijing Collaborative Innovative Re- those that lead to medial degeneration (4). Medial changes, which † search Center for Cardiovascular Diseases, Beijing 100029, China; Department of can result from excessive protease-mediated destruction of the Pathology, Aviation General Hospital of China Medical University, Beijing 100012, China; ‡Beijing Hospital of Traditional Chinese Medicine, Capital Medical Univer- extracellular matrix (ECM), weaken the aortic wall and make it sity, Beijing 100010, China; and xDepartment of Pharmacology and Institute for prone to rupture. Proteolytic enzymes, such as matrix metal- Translational Medicine and Therapeutics, Perelman School of Medicine, University loproteinases (MMPs), can primarily degrade various compo- of Pennsylvania, Philadelphia, PA 19104 nents of the ECM (5) and are implicated in the pathogenesis of 1W.R., Y.L., and X.W. contributed equally to this work. aortic aneurysm and dissection (6–10). MMP9, which is pre- ORCIDs: 0000-0001-8938-3420 (X.W.); 0000-0002-2975-7336 (C.P.); 0000-0003- 3421-3226 (Y.M.); 0000-0002-9143-4909 (S.Z.); 0000-0002-9038-4014 (F.L.). dominantly released from macrophages and neutrophils, has been well studied in the process of TAD and aneurysm. Genetic Received for publication August 9, 2016. Accepted for publication December 28, 2017. and pharmaceutical depletion of MMP9 can protect against the b This work was supported by the Beijing Nova Program (Grant Z151100000315067), effects of -aminopropionitrile monofumarate (BAPN), together the National Natural Science Foundation of China (Grants 81770250, 91339000, with angiotensin II–induced TAD (9). MMP2, which is mainly 81400194, and 81770468), the Chinese Ministry of Science and Technology (Grant from SMCs, increases immediately after the onset of aortic 2016YFC0903000), the Beijing Natural Science Foundation (Grants 7142030 and 7162030), and the Program for Changjiang Scholars and Innovative Research Team dissection (11). Using neutralizing Ab against MMP2 or in University (Grant IRI1074). knockout of MMP2 can prevent aneurysms in Marfan mice Address correspondence and reprint requests to Dr. Jie Du, Beijing Institute of Heart (12, 13). Therefore, rigorous regulation of MMP expression and Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, 2 Anzhen Road, activity is crucial for homeostasis of the ECM. MMP expression Chaoyang District, Beijing 100029, China. E-mail address: [email protected] can be regulated by multiple factors, including proinflammatory The online version of this article contains supplemental material. cytokines, growth factors, and hypoxia (4, 14). Abbreviations used in this article: AAA, abdominal aortic aneurysm; AP, alternative pathway; BAPN, b-aminopropionitrile monofumarate; CP, classical pathway; ECM, Infiltration of various immune cells has been found in the media extracellular matrix; KO, knockout; LP, lectin pathway; MMP, matrix metalloprotei- and adventitia of dissected aortic specimens and may contribute to nase; MRI, magnetic resonance imaging; qPCR, quantitative PCR; SMC, smooth aortic rupture (1). The complement system is an important driver muscle cell; TAD, thoracic aortic dissection; WT, wild-type. of inflammation and is capable of eliciting a proinflammatory Copyright Ó 2018 by The American Association of Immunologists, Inc. 0022-1767/18/$35.00 response by recruitment of immune cells. Complement is activated www.jimmunol.org/cgi/doi/10.4049/jimmunol.1601386 1830 KNOCKOUT OF C3aR PREVENTS DEVELOPMENT OF TAD through three pathways, including the classical pathway (CP), the Magnetic resonance imaging (MRI) was performed using an M2 compact lectin pathway (LP), and the alternative pathway (AP). All three MRI system (Aspect Imaging, Shoham, Israel) with mice in the prone pathways converge at a central enzyme, C3 convertase, which position on top of a microscopy single-loop surface coil (diameter = 35 mm). Morphology of the thoracic aorta was assessed by imaging, as previously enzymatically cleaves C3 (15, 16). Among the three pathways, AP described (24). is involved in elastase-induced development of abdominal aortic Measurement of plasma anaphylatoxin levels aneurysm (AAA), in which the AP C3 convertase components factor B and properdin play a critical role (17, 18). The anaphy- Plasma levels of anaphylatoxin C3a, C4a, and C5a in patients with TAD and latoxin C3a, which is released by C3 cleavage, is regarded as a healthy controls were determined using a BD Cytometric Bead Array proinflammatory stimulator in a variety of diseases (19, 20). (BBA) Human Anaphylatoxin Kit (BD Biosciences, Franklin Lakes, NJ), according to the instruction manual. Plasma from BAPN- or vehicle-treated Blockade of C3a and C5a activity together protects against de- mice was collected, and C3a levels were determined by ELISA (Uscn, velopment of AAA in mice, but inhibition of C3a or C5a alone has Wuhan, China), as previously described (25, 26). no effect (17). The pathogenesis