MicroRNA Regulation of Macrophage Polarization in Muscle Regeneration

肌肉再生中巨噬细胞极化的 MicroRNA 调节

• 批准号: 8391644
• 负责人: PAULA K SHIREMAN
• 金额: --
• 依托单位: SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8391644
• 关键词: Acute; Adjuvant; Adverse effects; Affect; Afghanistan; Amaze; Amputation; Animals; Area; Biological; Bone Marrow; Bone Marrow Cells; CC chemokine receptor 2; Cell Differentiation process; Cell physiology; Cell surface; Cells; Chronic; Complex; Data; Defect; Development; Disease; Event; Gene Expression; Goals; Healed; Human; Immune; Impairment; In Vitro; Individual; Inflammation; Inflammatory; Injury; Lead; Leg; Leukocytes; Limb Salvage; Limb structure; Mediating; Medical; Messenger RNA; MicroRNAs; Modeling; Mus; Muscle; Muscle Fibers; Natural regeneration; Oligonucleotides; Outcome; Patients; Population; Process; Proliferating; RNA; Recovery; Regulation; Research; Resolution; Role; Skeletal Muscle; Skeletal muscle injury; Skin; Soldier; Stem cells; Surface; System; Testing; Therapeutic; Tissue Engineering; Tissues; Trauma; Travel; Untranslated RNA; Veterans; War; Wild Type Mouse; Wound Healing; angiogenesis; arm; base; chemokine; combat; cytokine; defined contribution; design; healing; improved; in vivo; injured; innovation; locked nucleic acid; loss of function; macrophage; monocyte; mouse model; muscle regeneration; novel; novel therapeutics; regenerative; research study; satellite cell; soft tissue; tissue regeneration; tissue repair; wound

DESCRIPTION (provided by applicant): Stem cells and tissue regeneration have great therapeutic promise for treatment of a wide variety of medical conditions. For example and relevant to the current application, extremity injuries compromise 50-60% of all combat casualties observed in Iraqi/Afghanistan War Veterans resulting in large soft tissue defects (muscle and skin) and high amputation rates. Skeletal muscle, while being the tissue most vulnerable to ischemic damage in the extremities, also has an amazing potential to regenerate due to satellite cells. Satellite cells are stem cells that reside in skeletal muscle and with muscle injury, can proliferate and fuse together or with damaged muscle fibers to regenerate muscle; macrophages are critical to this process. Multiple types of macrophages participate in the regenerative process; classically activated (M1), wound healing (M2a) and regulatory (M2c) macrophage subsets are present in skin wounds and regenerating skeletal muscle; promoting inflammation, tissue repair and resolution of inflammation, respectively. However, the regulation of macrophage specialization (polarization) by microRNAs (miRNAs), and the consequential effects of macrophage subsets on muscle regeneration have not been elucidated. MiRNAs are small, noncoding RNAs that inhibit gene expression, thereby regulating many processes, including immune cell differentiation. A better understanding of the mechanisms of skeletal muscle regeneration and skin wound healing, and the influence of macrophage polarization on these events, could lead to new and adjunct therapies for limb salvage. Our long-term goal is to define the influence of inflammation, including the chemokine system, in angiogenesis, wound healing and skeletal muscle regeneration. We have extensively studied the importance of the CC Chemokine Receptor 2 (CCR2) in muscle regeneration. CCR2 is crucial for monocyte/macrophage recruitment and differentiation. Following muscle injury, CCR2-/- mice have impairments in macrophage recruitment, angiogenesis and muscle regeneration compared to wild type (WT) mice. Importantly, macrophage recruitment and muscle regeneration defects can be reversed in CCR2-/- mice by providing WT bone marrow, thus, CCR2 expression on bone marrow-derived cells is critical for normal muscle regeneration and macrophages are the likely BM-derived cell that mediates this outcome. The following 3 specific aims will be tested: 1) Define the in vitro regulation of macrophage polarization by selected miRNAs (miR-21 and -147). 2) Establish the mRNA targets of selected miRNAs (miR-21 and -147) during macrophage polarization and 3) Determine the biological effects of individual miRNAs on in vivo macrophage subsets and coordinated biological events during wound healing. By modulating macrophage polarization via increased or decreased miRNA expression, we seek to improve wound healing and decrease the adverse affects of acute and chronic inflammation present in many diseases that affect the Veteran population. The proposed studies are innovative because they will help define the contribution of miRNAs to macrophage polarization and subsequent muscle regeneration and wound healing. The combination of in vitro and in vivo studies will collectively identify miRNAs important for macrophage polarization, determine the mRNA targets, and assess any effects on muscle regeneration and wound healing. Given the availability of locked-nucleic-acid-modified oligonucleotide (LNA-antimiR), RNA oligonucleotides complementary to specific miRNAs that can be used in animals to decrease miRNA expression, a new therapeutic class of agents could become available for humans. The significance of this research is that a better understanding of the mechanisms of skeletal muscle regeneration and wound healing could lead to the design of novel primary or adjuvant treatments for improved limb salvage using miRNA- altering compounds.

描述（由申请人提供）： 干细胞和组织再生对于治疗多种医疗状况具有巨大的治疗前景。例如，与当前的应用相关，在伊拉克/阿富汗战争退伍军人中观察到的所有战斗伤亡中，四肢损伤占 50-60%，导致大的软组织缺陷（肌肉和皮肤）和高截肢率。骨骼肌虽然是四肢最容易遭受缺血性损伤的组织，但由于卫星细胞的作用，也具有惊人的再生潜力。卫星细胞是存在于骨骼肌中的干细胞，在肌肉损伤时可以增殖并融合在一起或与受损的肌纤维融合以再生肌肉；巨噬细胞对此过程至关重要。多种类型的巨噬细胞参与再生过程；经典活化（M1）、伤口愈合（M2a）和调节（M2c）巨噬细胞亚群存在于皮肤伤口和再生骨骼肌中；分别促进炎症、组织修复和炎症消退。然而，microRNA (miRNA) 对巨噬细胞特化（极化）的调节以及巨噬细胞亚群对肌肉再生的影响尚未阐明。 miRNA 是小型非编码 RNA，可抑制基因表达，从而调节许多过程，包括免疫细胞分化。更好地了解骨骼肌再生和皮肤伤口愈合的机制，以及巨噬细胞极化对这些事件的影响，可能会导致新的保肢疗法和辅助疗法。我们的长期目标是确定炎症（包括趋化因子系统）对血管生成、伤口愈合和骨骼肌再生的影响。我们广泛研究了 CC 趋化因子受体 2 (CCR2) 在肌肉再生中的重要性。 CCR2 对于单核细胞/巨噬细胞的招募和分化至关重要。与野生型 (WT) 小鼠相比，肌肉损伤后，CCR2-/- 小鼠的巨噬细胞募集、血管生成和肌肉再生均受到损害。重要的是，通过提供 WT 骨髓，可以逆转 CCR2-/- 小鼠中的巨噬细胞募集和肌肉再生缺陷，因此，骨髓来源细胞上的 CCR2 表达对于正常肌肉再生至关重要，而巨噬细胞可能是介导此结果的 BM 来源细胞。将测试以下 3 个具体目标： 1) 定义选定 miRNA（miR-21 和 -147）对巨噬细胞极化的体外调节。 2) 在巨噬细胞极化过程中建立所选 miRNA（miR-21 和 -147）的 mRNA 靶标，以及 3) 确定单个 miRNA 对体内巨噬细胞亚群的生物学效应以及伤口愈合过程中协调的生物学事件。通过增加或减少 miRNA 表达来调节巨噬细胞极化，我们寻求改善伤口愈合并减少影响退伍军人群体的许多疾病中存在的急性和慢性炎症的不利影响。拟议的研究具有创新性，因为它们将有助于确定 miRNA 对巨噬细胞极化以及随后的肌肉再生和伤口愈合的贡献。体外和体内研究的结合将共同鉴定对巨噬细胞极化重要的 miRNA，确定 mRNA 靶标，并评估对肌肉再生和伤口愈合的影响。鉴于锁核酸修饰寡核苷酸 (LNA-antimiR) 的可用性，即与特定 miRNA 互补的 RNA 寡核苷酸，可用于动物体内降低 miRNA 表达，一类新的治疗药物可能可用于人类。这项研究的意义在于，更好地了解骨骼肌再生和伤口愈合的机制可能会导致设计新的主要或辅助治疗方法，以使用改变 miRNA 的化合物来改善保肢效果。