Arterial stiffening and SMC mechanobiology in Hutchinson-Guilford Progeria Syndrome

哈钦森-吉尔福德早衰综合症中的动脉硬化和 SMC 力学生物学

• 批准号: 9816369
• 负责人: Richard Assoian
• 金额: $ 42.22万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9816369
• 关键词: Abbreviations; Acceleration; Address; Affect; Age; Aorta; Apolipoprotein E; Appearance; Arteries; Atherosclerosis; Blood Pressure; Cardiovascular Diseases; Cardiovascular Pathology; Cell Differentiation process; Cells; Cellular biology; Cessation of life; Characteristics; Child; Cholesterol; Coupling; Data; Defect; Disease; Down-Regulation; Enzymes; Event; Extracellular Matrix; Farnesyl Transferase Inhibitor; Fibronectins; Gene Chips; Gene Expression; Genes; Human; Human Characteristics; In Vitro; Knockout Mice; Lead; Link; LoxP-flanked allele; MYH11 gene; Mechanics; Modeling; Molecular; Mus; Mutation; Myocardial Infarction; Names; Patients; Phenocopy; Phenotype; Premature aging syndrome; Progeria; Property; Protein-Lysine 6-Oxidase; Proteins; Risk Factors; Smooth Muscle; Smooth Muscle Actin Staining Method; Smooth Muscle Myocytes; Stretching; Stroke; Syndrome; Tamoxifen; Teenagers; Testing; Traction Force Microscopy; Transgenic Organisms; Vascular Smooth Muscle; Vasoconstrictor Agents; age related; aged; arterial stiffness; autosomal dominant mutation; cell age; experimental study; human disease; in vivo; in vivo Model; interest; lead candidate; mouse model; mutant; normal aging; novel; osteopontin; premature; rare genetic disorder; response; sex

SUMMARY Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic disease of premature aging caused by an autosomal dominant mutation in LMNA, the gene encoding laminA. The mutant protein, LmnAG608G has been named "Progerin." Children with HGPS typically die in their teenage years as a consequence of CVD (atherosclerosis, myocardial infarction and/or stroke). Remarkably, CVD and death occurs in the absence of high cholesterol, but the arteries of HGPS patients are abnormally stiff, and arterial stiffness has been identified as a cholesterol-independent risk factor for CVD. Moreover, we previously showed that in vivo inhibition of arterial stiffening reduces atherosclerosis in apoE-null mice. Because Progerin is aberrantly farnesylated, therapies for HGPS have focused farnesyltransferase inhibitors (FTIs), but those studies do not directly address the cardiovascular pathology that is thought to trigger early death in HGPS. We recently obtained the LMNAG609G mouse that corresponds to the LMNAG608G mutation in human HGPS and show here that this mouse phenocopies the human disease in showing premature arterial stiffening. Immunostaining of arterial sections and an ECM expression array have identified two lead candidates for this premature arterial stiffening, and those will be studied here. We also found that HGPS arteries are deficient in their response to vasoconstrictors, and our preliminary results link this contractility defect to a striking uncoupling of two well established smooth muscle differentiation/CArG genes: expression of smooth muscle myosin heavy chain (SM-MHC) is reduced in HGPS while smooth muscle actin (SMA) levels are relatively normal. Importantly, we have been able to recapitulate this in vivo phenotype of uncoupled SM-MHC vs. SMA expression in primary smooth muscle cells (SMCs) from WT and HGPS aortas. SM-MHC is among the most important regulators of the high contractility state in differentiated SMCs. Thus, these findings, and related traction force microscopy (TFM) experiments in Preliminary Studies, lead us to a new model for premature arterial stiffening in HGPS: the expression of mutant LaminA (Progerin) leads to a preferential downregulation of SM-MHC, and this locks HGPS SMCs into a novel intermediate tensional state in which they behave more like a de-differentiated SMC, producing ECM proteins and ECM remodeling enzymes that lead to an acceleration of arterial stiffening. Aim 1 will use age-matched WT and HGPS mice to test for causal relationships between i) ECM remodeling events and premature arterial stiffening and ii) SM-MHC expression and arterial ECM remodeling. Aim 2 will use isolated SMCs to identify molecular mechanisms and causal relationships between HGPS, SM-MHC expression, cellular contractility, and ECM remodeling. It will also establish molecular mechanisms by which expression of Progerin, and possibly WT LaminA, affects SM-MHC gene expression. Aim 3 will test for similarities and differences between arterial stiffening, ECM remodeling and SM-MHC/SMA expression in normal aging vs. HGPS.

概括 哈钦森-吉尔福德早衰综合症 (HGPS) 是一种罕见的过早衰老遗传性疾病，由 LMNA（编码 laminA 的基因）的常染色体显性突变。突变蛋白 LmnAG608G 已被 命名为“Progerin”。患有 HGPS 的儿童通常会在青少年时期因心血管疾病而死亡 （动脉粥样硬化、心肌梗塞和/或中风）。值得注意的是，CVD 和死亡发生在缺乏 高胆固醇，但HGPS患者的动脉异常僵硬，动脉僵硬已 被确定为 CVD 的胆固醇独立危险因素。此外，我们之前表明，在体内 抑制动脉硬化可减少 apoE 缺失小鼠的动脉粥样硬化。因为早老蛋白异常 法尼基化后，HGPS 的治疗重点关注法尼基转移酶抑制剂 (FTI)，但这些研究并没有 直接解决被认为会引发 HGPS 过早死亡的心血管病理学问题。 我们最近获得了与人类 HGPS 中的 LMNAG608G 突变相对应的 LMNAG609G 小鼠，并且 此处显示，这只小鼠的表型模仿了人类疾病，表现出动脉过早硬化。 动脉切片的免疫染色和 ECM 表达阵列已确定了该研究的两个主要候选者 动脉过早硬化，这些将在这里进行研究。我们还发现 HGPS 动脉缺乏 他们对血管收缩剂的反应，以及我们的初步结果将这种收缩性缺陷与惊人的 两个成熟的平滑肌分化/CArG基因的解偶联：平滑肌的表达 HGPS 中肌球蛋白重链 (SM-MHC) 减少，而平滑肌肌动蛋白 (SMA) 水平相对较低 普通的。重要的是，我们已经能够重现未偶联 SM-MHC 与 SMA 的体内表型 WT 和 HGPS 主动脉的原代平滑肌细胞 (SMC) 中的表达。 SM-MHC 是其中最 分化的 SMC 中高收缩状态的重要调节因子。因此，这些发现以及相关 初步研究中的牵引力显微镜（TFM）实验为我们提供了一种新的早产儿模型 HGPS 中的动脉硬化：突变体 LaminA (Progerin) 的表达导致优先下调 SM-MHC，这将 HGPS SMC 锁定在一种新颖的中间张力状态，在这种状态下它们的行为更加 就像去分化的 SMC，产生 ECM 蛋白和 ECM 重塑酶，从而导致 加速动脉硬化。目标 1 将使用年龄匹配的 WT 和 HGPS 小鼠来测试因果关系 i) ECM 重塑事件与动脉过早硬化和 ii) SM-MHC 表达之间的关系 和动脉 ECM 重塑。目标 2 将使用分离的 SMC 来识别分子机制和因果关系 HGPS、SM-MHC 表达、细胞收缩性和 ECM 重塑之间的关系。它还将 建立 Progerin 和可能的 WT LaminA 表达影响 SM-MHC 的分子机制 基因表达。目标 3 将测试动脉硬化、ECM 重塑之间的异同 和 SM-MHC/SMA 在正常衰老中的表达与 HGPS 的比较。