Molecular Mechanisms of Impaired Angiogenesis in Aging Gastric Mucosa

老化胃粘膜血管生成受损的分子机制

• 批准号: 7929333
• 负责人: ANDRZEJ S TARNAWSKI
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7929333
• 关键词: 5' -AMP-activated protein kinase; Acetylation; Acute; Age Reporting; Age-Years; Aging; Albumins; American; Angiogenesis Inhibition; Angiogenesis Inhibitors; Angiogenic Factor; Angiostatins; Antibodies; Apoptosis; Area; Arthritis; Asses; Binding; Biochemical; Blood Vessels; Blood capillaries; CREB1 gene; Cell Nucleus; Cell physiology; Cells; Characteristics; Chronic; Cicatrix; Clinical; Complementary DNA; Connective Tissue; DNA Binding; Dermal; Down-Regulation; Duodenal Ulcer; Economics; Endostatins; Endothelial Cells; Enzymes; Epithelial; Equilibrium; Ethanol; Exhibits; Extravasation; Fluorescein; Funding; Gastric mucosa; Gastric ulcer; Gastritis; Gelatinase B; Gene Activation; Gene Expression; Genes; Genetic Transcription; Goals; Granulation Tissue; HIF1A gene; Healed; Health; Heat shock proteins; Heat-Shock Proteins 90; Human; Hypoxia; Hypoxia Inducible Factor; Image; Imagery; Impaired wound healing; Impairment; Importins; In Vitro; Incidence; Indomethacin; Infarction; Injury; Investigation; Literature; Mediating; Molecular; Morbidity - disease rate; Myocardium; Natural regeneration; Non-Steroidal Anti-Inflammatory Agents; Nuclear; Nutrient; Organ; Oxygen; Pain; Patients; Peptic Ulcer; Pericytes; Permeability; Phosphorylation; Physiological; Plasmids; Population; Predisposition; Prevalence; Properdin; Proteins; Publications; Rattus; Relative (related person); Research; Research Design; Resolution; Role; STAT3 gene; Serum; Site; Small Interfering RNA; Stimulus; Stomach; Structure; Techniques; Technology; Testing; Therapeutic Intervention; Time; Tissues; Transcriptional Activation; Ulcer; Up-Regulation; Vascular Endothelial Growth Factor Receptor-2; Vascular Endothelial Growth Factors; Vascular Permeabilities; Veterans; Work; Wound Healing; age related; alcohol response; alpha Karyopherins; angiogenesis; annexin A5; autocrine; base; capillary; density; gene therapy; healing; high risk; hypoxia inducible factor 1; improved; in vivo; indexing; injured; instrument; mortality; mouse model; mutant; neutralizing antibody; novel; novel therapeutic intervention; novel therapeutics; overexpression; patient population; promoter; protein expression; protein kinase P; receptor; response; response to injury; stem; transcription factor; treatment strategy

DESCRIPTION (provided by applicant): ABSTRACT Background/Rationale: Gastric mucosa of aging humans and rats (aging gastric mucosa) exhibits increased susceptibility to injury and delayed healing. Healing of gastric injury requires re-establishment of mucosal blood vessels through the formation of new vessels (angiogenesis). Previous studies showed that healing of gastric injury in aging rats is delayed and impaired vs. young rats; but the underlying mechanisms are not explained, and angiogenesis in aging gastric mucosa has not been examined before. Our long-term objectives are: 1) to identify the molecular mechanisms of impaired angiogenesis in aging gastric mucosa and based on these findings 2) to develop new therapeutic strategies for treatment and reversing aging- related impaired angiogenesis and delayed healing. Our overall hypothesis is that an imbalance between angiogenic and anti-angiogenic factors suppresses angiogenesis and inhibits healing of injury in aging gastric mucosa. In this project, we will examine the mechanisms responsible for this imbalance and its consequences, ultimately demonstrating that manipulating this imbalance can improve angiogenesis and healing. We hypothesize that the mechanisms underlying impaired angiogenesis in aging gastric mucosa are: 1) Aging-related alterations in gastric microvascular endothelial cell (EC) function - reduced transcriptional activation of the VEGF gene due to: A) downregulation of importin and B) downregulation of the transcriptional factors P-CREB and P-STAT3, 2) Angiogenic imbalance due to reduced pro-angiogenic VEGF and concomitant increased anti-angiogenic endostatin in aging gastric mucosa leads to inhibition of angiogenesis, and 3) Therapeutic interventions aimed at the mechanisms: A) local VEGF gene therapy, B) upregulation and activation of importin with AICAR treatment, or C) specific neutralizing antibody against endostatin will significantly reverse impaired angiogenesis, and will improve microvascular regeneration and healing of chronic gastric ulcers in aging rats. The rationale for these hypotheses stems from our preliminary work that demonstrated in gastric mucosa of aging (vs. young) rats significantly decreased VEGF, increased endostatin, reduced angiogenesis in response to injury, and distorted and impaired mucosal healing. Furthermore, we showed that EC isolated from the gastric mucosa of aging rats exhibit reduced VEGF gene activation, impaired in vitro angiogenesis and reduced angiogenic response to hypoxia. We also demonstrated that importin is an essential requirement for VEGF gene activation and for angiogenesis since its silencing with specific siRNA significantly reduced angiogenesis in young EC. Conversely, activation of importin by treatment with AICAR significantly reversed impaired angiogenesis in aging EC. Research Design: We will examine the above hypotheses in EC isolated from gastric mucosa of young and aging rats and in vivo in gastric mucosa of aging vs. young rats following injury and ulceration. In vitro studies will include analysis of: expression of proteins involved in angiogenesis - VEGF, VEGFR2, P-VEGFR2 as well as HSP90, HIF1, HIF1, importin , AMPK, P-CREB and P-STAT3; their interactions and binding of HIF1, P-CREB and P- STAT3 to the VEGF gene. For in vivo studies, we will examine in gastric mucosa of rats, injury (erosion and ulcer) and will quantitatively asses angiogenesis during gastric ulcer healing, and determine expression of endostatin, MMP9 & others listed proteins. Significance: In 2006, ~39 million Americans (12% of population) were 65 years of age or older, and this number is projected reach ~70 million by 2030. This population is at high risk of tissue and organ injuries. Impaired angiogenesis is a key factor in delayed healing, morbidity and mortality. The central topic of our project is angiogenesis, a critical requirement for "wound healing", which is one of the VA priority areas. PUBLIC HEALTH RELEVANCE: Relevance to Veterans Health. In 2006 nearly 39 million Americans (12% of population) were 65 years of age or older, and this number is projected to grow to about 70 million by 2030. The veteran patient population is aging and patients 70 years or older constitute a significant proportion. This population is at high risk of tissue and organ injuries. Impaired angiogenesis is a key factor in delayed tissue injury healing, morbidity, and mortality. Impaired healing of wounds, both internal, such as gastric and duodenal ulcers or external, such as non-healing dermal ulcers constitute important clinical and economic problems. Gastric injury - gastritis and ulcers are frequently encountered in VA patients often as a result of chronic treatment NSAIDs for arthritis or pain. Lifetime prevalence of gastroduodenal ulcers in the US population is 3-6% but their incidence among the VA population is 2.5-fold higher. The central topic of our proposed investigations is directly related to angiogenesis that is a critical requirement for "wound healing", which is one of the VA priority areas.

描述（由申请人提供）： 摘要背景/理由：衰老的人和大鼠的胃粘膜（衰老的胃粘膜）表现出增加对损伤和延迟愈合的易感性。胃损伤的愈合需要通过形成新血管（血管生成）来重建粘膜血管。先前的研究表明，衰老大鼠胃损伤的愈合被延迟和受损与年轻大鼠。但是，没有解释潜在的机制，并且以前尚未检查胃粘膜老化的血管生成。我们的长期目标是：1）确定胃粘膜衰老中血管生成受损的分子机制，并基于这些发现2）制定新的治疗策略，以治疗和逆转与衰老相关的受损血管生成和延迟愈合。我们的总体假设是，血管生成和抗血管生成因子之间的不平衡抑制了血管生成，并抑制胃粘膜衰老的损伤愈合。在这个项目中，我们将检查导致这种不平衡及其后果的机制，最终表明操纵这种失衡可以改善血管生成和愈合。我们假设胃粘膜衰老中的血管生成的基本机制为：1）与胃微血管内皮细胞功能（EC）功能的衰老相关变化 - 降低VEGF基因的转录转录激活：降低的血管生成VEGF和伴随抗血管生成的抗血管生成性内接抑制素在衰老的胃粘膜中会导致抑制血管生成，而3）旨在进行这些机制的治疗性干预措施：a）局部VEGF基因治疗，b）与ANICAR的特定污染物的特异性侵蚀，b）血管生成，并将改善衰老大鼠慢性胃溃疡的微血管再生和愈合。这些假设的基本原理源于我们在衰老的胃粘膜（与年轻）大鼠胃粘膜中证明的初步工作，显着降低了VEGF，内静脉毒素增加，造成损伤的血管生成减少，扭曲和粘膜愈合受损。此外，我们表明，从衰老大鼠的胃粘膜中分离出来的EC表现出降低的VEGF基因激活，体外血管生成受损，对缺氧的血管生成反应降低。我们还证明了Importin是VEGF基因激活和血管生成的基本要求，因为其对特定siRNA的沉默显着降低了年轻EC的血管生成。相反，通过用AICAR治疗对导入的激活显着逆转EC衰老的血管生成受损。研究设计：我们将研究从年轻大鼠和衰老大鼠的胃粘膜中分离出的EC中的上述假设，以及在受伤和溃疡后衰老与年轻大鼠的胃粘膜中的体内。体外研究将包括以下分析：参与血管生成的蛋白质的表达-VEGF，VEGFR2，P-VEGFR2以及HSP90，HIF1，HIF1，HIF1，Importin，Ampk，P-Creb和P-STAT3；它们的相互作用以及HIF1，p-creb和p stat3与VEGF基因的结合。对于体内研究，我们将检查大鼠的胃粘膜，损伤（侵蚀和溃疡），并将在胃溃疡愈合过程中定量地囊血管生成，并确定内接抑制素，MMP9和其他列出的蛋白质的表达。意义：2006年，约有3900万美国人（占人口的12％）年龄在65岁以上，到2030年，这一数字预计约为7000万。该人口处于组织和器官损伤的高风险。血管生成受损是延迟愈合，发病率和死亡率的关键因素。我们项目的中心主题是血管生成，这是“伤口愈合”的关键要求，这是VA优先领域之一。 公共卫生相关性： 与退伍军人健康有关。 2006年，近3900万美国人（占人口的12％）年龄在65岁以上，到2030年，这一数字预计将增长到约7,000万。老将患者人口正在老龄化，患者70岁或70岁以上占很大的比例。该人群有组织和器官损伤的高风险。血管生成受损是延迟组织损伤愈合，发病率和死亡率的关键因素。内部伤口的治愈受损，例如胃溃疡和外部溃疡，例如非治疗皮肤溃疡构成了重要的临床和经济问题。胃损伤 - 胃炎和溃疡经常在VA患者中经常遇到，这是由于慢性治疗NSAID的关节炎或疼痛而导致的。美国人口中胃终生溃疡的终生患病率为3-6％，但VA人口的发病率高2.5倍。我们提出的研究的中心主题与血管生成直接相关，这是“伤口愈合”的关键要求，这是VA优先区域之一。