Progression of Arterial Aging: the Local MCP-1/MMP-2/TGF-beta 1 Signaling Loop

动脉老化的进展：局部 MCP-1/MMP-2/TGF-beta 1 信号环路

• 批准号: 10007327
• 负责人: Mingyi Wang
• 金额: $ 46.43万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10007327
• 关键词: Actins; Adult; Age; Aging; Angiotensin II; Angiotensin II Receptor; Animal Model; Animals; Atherosclerosis; Blood Pressure; CC chemokine receptor 2; CCL2 gene; Cells; Cellularity; Chronic; Cleaved cell; Co-Immunoprecipitations; Collagen; Collagen Type I; Complex; Cytoskeleton; Deposition; Diffuse; Down-Regulation; ETS1 gene; Elastic Fiber; Elastin Fiber; Elderly; Equilibrium; Exhibits; Extracellular Matrix; Fibrosis; Friction; Gelatinases; Genes; Genetic Transcription; Health; Human; Hypertension; Immunoblotting; In Situ; In Vitro; Incidence; Individual; Infiltration; Inflammation; Integrins; Interstitial Collagenase; Intervention; Length; Losartan; MADH2 gene; Matrix Metalloproteinase Inhibitor; Matrix Metalloproteinases; Mechanics; Molecular; Mothers; Nodal; Pathologic; Phenotype; Phosphorylation; Physiological; Play; Production; Property; Proteins; Rattus; Recombinants; Regulation; Risk Factors; Role; Signal Transduction; Signaling Molecule; Smooth Muscle Myocytes; TGFB1 gene; Therapeutic; Thoracic aorta; Time; Translations; Triad Acrylic Resin; Vascular Diseases; Vascular Smooth Muscle; aged; arterial remodeling; arterial stiffness; base; cell age; human model; in vivo; juvenile animal; mature animal; novel; novel strategies; overexpression; preservation; pressure; prevent; proendothelin 1; response; senescence; therapy design

The coexistence of vascular smooth muscle cell (VSMC) infiltration (via invasion and proliferation) and collagen deposition within a diffusely thickened intima is a salient feature of central arterial wall inflammation that accompanies advancing age. However, the molecular and cellular mechanisms involved remain undefined. Immunostaining and immunoblotting of rat aortae demonstrate that a triad of proinflammatory molecules MCP-1, TGF-1, and MMP-2 increase within the aging aortic wall. Treating VSMCs, isolated from 8-mo-old rats (young), to MCP-1, via the CC-chemokine receptor 2 (CCR-2), produces both an increase in TGF-1 activity, up to levels of untreated VSMC from 30-mo-old (old) FXBN rats, and a concurrent increase in MMP-2 activation. Furthermore, treating young VSMCs with TGF-1 increases the levels of MCP-1 and MMP-2 activation, to levels of untreated VSMC from old rats. This autocatalytic signaling loop that enhances collagen production and invasiveness of VSMCs is effectively suppressed by silencing the MCP-1 gene, or treating with a CCR2 antagonist, or through MMP-2 inhibition. Certain levels of MCP-1, MMP-2, or TGF-1 activity trigger a feed-forward signaling mechanism that is implicated in the initiation and progression of adverse age-associated arterial wall senescent remodeling. Interventions that suppress this signaling loop may potentially lessen age-associated adverse arterial remodeling. The MMP-associated activation of TGF-1 plays an important role in the stiffening of aging VSMCs. Distinct material properties of primary VSMC cells isolated from the thoracic aorta of adult (8 months) vs. aged (30 months) F344XBN rats were seen. Individual VSMCs derived from aged animals showed a tense internal network of the actin cytoskeleton, exhibiting increased stiffness and frictional (loss) moduli than those derived from the adult animals. This discrete mechanical response was long-lived in culture and was persistent across a physiological range of matrix rigidity. Strikingly, TGF-1 emerged as a specific modifier of age-associated VSMC stiffening in vitro. TGF-1 reinforced the mechanical phenotype of arterial aging in VSMCs on multiple time and length scales through clustering of mechanosensitive 51 and v3 integrins. Taken together, these studies identify a novel nodal point for the long-range regulation of VSMC stiffness and serve as a proof-of-concept that the broad-based inhibition of TGF-1 expression, or TGF-1 signal transduction in VSMC, may be a useful therapeutic approach to mitigate the pathologic progression of central arterial wall stiffening associated with aging. Indeed, we proved that the inhibition of MMP activation decelerates the age-associated arterial proinflammation and its attendant increase in arterial pressure. Chronic administration, for 8 months, of a broad-spectrum MMP inhibitor, PD166793, via a daily gavage, to 16-month-old rats markedly blunted the expected age-associated increases in arterial pressure. This was accompanied by the following: (1) inhibition of the age-associated increases in aortic gelatinase and interstitial collagenase activity in situ; (2) preservation of the elastic fiber network integrity; (3) a reduction of collagen deposition; (4) a reduction of MCP-1 and TGF-1 activation; (5) a decrease in the activity of the profibrogenic signaling molecule SMAD 2/3 (Sma and Mad (Mothers against decapentaplegic)-2/3) phosphorylation; (6) inhibition of proendothelin 1 activation; and (7) downregulation of expression of V-Ets Avian Erythroblastosis Virus E26 Oncogene Homolog 1 ( Ets-1). Collectively, our results indicate that MMP inhibition retards age-associated arterial proinflammatory signaling, and this is accompanied by the preservation of intact elastin fibers, a reduction in collagen, and a blunting of age-associated increases in blood pressure. Our recent study has shown that a signaling relationship exists between angiotensin II (Ang II), TGF-1 and vasorin within aging VSMCs. In vivo studies in old (30-month-old) versus young (8-month-old) FXBN rats show that the aortic transcription and translation levels of vasorin markedly decreases with aging. In vitro studies of early passage VSMCs from old versus young rat aortae indicate that the abundance of vasorin protein is substantially reduced with aging. Ang II-associated reduction of vasorin protein abundance in young VSMC and age-associated changes in vasorin protein levels are reversed when treated with Losartan (Los), an Ang II receptor (AT1) antagonist, in both in vitro and in vivo conditions, suggesting constitutive activation of AT1 signaling within the aged arterial wall. Dual immunolabeling and co-immunoprecipitation demonstrate that the co-incidence and physical interaction of vasorin and TGF-1 within VSMC are significantly decreased with aging. Importantly, treating young VSMC and young animals with Ang II increases p-SMAD2/3 and collagen type I production, mimicking old cells. and are abolished or substantially mitigated by treating with Los, or through the overexpression of vasorin or exogenous recombinant human-vasorin protein. In contrast, when old VSMCs are treated with Los, decreases in the production of p-SMAD2/3 and collagen type I are seen. An imbalance in the Ang II/TGF-1/vasorin signaling cascade is created, a feature of the aged arterial wall, that enhances collagen production in VSMCs. In addition, age-associated arterial vasorin is closely associated with enhanced capacity of MMP activation. Activated MMP-2/9 can cleave the full-length of vasorin, and is blocked by MMP Inhibitor, GM6001, in vitro and PD166793, in vivo. Thus, maintaining the balance of the full-length vasorin/TGF-1 signaling is a novel approach to hinder adverse age-associated extracellular matrix remodeling, a determinant of arterial stiffening. Taken together, this complex local signaling loop of MCP-1/MMP-2/TGF-1 plays a vital role in the initiation and progression of age-associated arterial intimal cellularity, fibrosis and relevant vascular diseases. Blocking this vicious cycle is a potential therapeutic approach to preserving arterial health with advancing age

在弥漫性增厚的内膜内，血管平滑肌细胞（VSMC）浸润（通过侵袭和增殖）和胶原沉积共存是随着年龄增长而发生的中央动脉壁炎症的一个显著特征。然而，所涉及的分子和细胞机制仍未明确。大鼠主动脉的免疫染色和免疫印迹显示，促炎分子MCP-1、TGF-1和MMP-2在老化的主动脉壁内增加。通过cc趋化因子受体2 （CCR-2）将8 mo大鼠（年轻）分离的VSMC处理为MCP-1，可产生TGF-1活性的增加，达到30 mo（老年）FXBN大鼠未处理VSMC的水平，并同时增加MMP-2激活。此外，用TGF-1治疗年轻VSMC可使MCP-1和MMP-2的激活水平提高到未治疗的老年大鼠VSMC水平。通过沉默MCP-1基因，或用CCR2拮抗剂治疗，或通过抑制MMP-2，可以有效地抑制这种增强胶原生成和VSMCs侵袭性的自催化信号环。特定水平的MCP-1、MMP-2或TGF-1活性触发前馈信号机制，该机制涉及与年龄相关的不良动脉壁衰老重塑的开始和进展。抑制这一信号循环的干预措施可能会潜在地减少与年龄相关的不良动脉重塑。