Novel Role of MAPK14 in Regulation of VSMC Contractile Phenotype

MAPK14 在 VSMC 收缩表型调节中的新作用

• 批准号: 8828776
• 负责人: Xiaochun Long
• 金额: $ 38.91万
• 依托单位: ALBANY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2019-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8828776
• 关键词: Address; Affect; Aorta; Arterial Disorder; Biological Assay; Blood Pressure; Blood Vessels; Carotid Arteries; Cell Differentiation process; Chemicals; Data; Development; Disease; Disease model; Endothelial Cells; Exhibits; Family; Gene Expression; Genes; Health; Human; In Vitro; Injury; Knockout Mice; Lesion; Ligation; Link; MAPK14 gene; Mediating; Modeling; Molecular; Mus; Nuclear Translocation; Pathway interactions; Phenotype; Phosphorylation; Phosphotransferases; Process; Protein Isoforms; RNA Interference; Regulation; Reporter; Resistance; Role; SB 203580; Serum Response Factor; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Smooth Muscle Myocytes; Subfamily lentivirinae; Therapeutic; Transducers; Transgenic Mice; Untranslated RNA; Vascular Diseases; Veins; Work; attenuation; base; combat; design; in vivo; inhibitor/antagonist; innovation; insight; knock-down; mouse model; myocardin; novel; novel strategies; novel therapeutics; programs

DESCRIPTION (provided by applicant): Vascular smooth muscle cells (VSMC) exhibit phenotypic plasticity that contributes to human vascular disease. Serum response factor (SRF) and the Myocardin family of coactivators (e.g., MRTFA) have emerged as key inducers of the VSMC contractile phenotype. Although much work exists on SRF-MRTFA-dependent gene expression, a critical gap exists with respect to our understanding of signaling pathways that converge upon SRF-MRTFA to negatively affect VSMC gene expression. We and others have proposed p38MAPK signaling as a critical signal transducer of TGF¿1-induced VSMC differentiation; however, all studies to date have relied upon the exclusive use of chemical inhibitors of p38MAPK (e.g., SB203580). Since such inhibitors likely have unknown effects un-related to p38MAPK, we performed small interference RNA knockdown studies of p38MAPK¿ (MAPK14), the major isoform of p38MAPK in VSMC targeted by SB compounds. Rather than inhibiting VSMC gene expression, as predicted by prior studies using SB compounds, we found knockdown of MAPK14 stimulates VSMC contractile gene expression. Using several well-defined vascular injury models, we found total and phosphorylated MAPK14 are enriched in the neointima of the vessel wall where phenotypically altered VSMC reside suggesting MAPK14 expression is somehow linked to the synthetic VSMC phenotype. New, exciting data show VSMC-specific Mapk14 knockout mice exhibit induced VSMC contractile gene expression and are completely resistant to injury-induced neointimal formation. Mechanistically, we have found that MAPK14 regulates MRTFA nucleo-cytoplasmic shuttling, a critical determinant of SRF-dependent VSMC contractile gene expression. Our most recent finding reveals depletion of MAPK14 up-regulates a novel Smooth muscle and Endothelial cell enriched long Non-Coding RNA (SENCR), that exerts positive effects on the VSMC contractile phenotype. Based on these findings, we have formulated the global hypothesis that MAPK14 antagonizes VSMC contractile phenotype and promotes vascular disease through dysregu- lation of MRTFA nuclear translocation and inhibition of SENCR. Three inter-related specific aims are pro- posed to address this hypothesis using novel mouse models and innovative concepts. In Aim 1, we will elucidate the role of MAPK14 in VSMC phenotypic plasticity leading to vascular disease. In Aim 2, we will elucidate the integrative role of MAPK14 and MRTFA in regulating VSMC differentiation. In Aim 3, we will elucidate the regulation and function of MAPK14-dependent inhibition of SENCR in VSMC. Collectively, these studies will illuminate an important and heretofore unrecognized role for MAPK14 in negatively regulating VSMC differentiation, thus providing fresh insight into the molecular control of VSMC phenotype. These studies also challenge the paradigm of p38MAPK as a pro-VSMC differentiation signaling pathway and will link this pathway to the antagonism of two key downstream targets (MRTFA and SENCR). Information gained through these studies has intriguing therapeutic potential for designing novel strategies to combat vascular diseases.

描述（由申请人提供）：血管平滑肌细胞（VSMC）表现出表型可塑性，有助于人类血管疾病。血清反应因子（SRF）和共激活因子（如MRTFA）的心肌素家族已成为VSMC收缩表型的关键诱导剂。尽管对SRF-MRTFA依赖性基因表达的研究已经开展了大量工作，但我们对汇聚在SRF-MRTFA上并对VSMC基因表达产生负面影响的信号通路的理解还存在一个关键的空白。我们和其他人提出p38MAPK信号是TGF¿1诱导的VSMC分化的关键信号换能器；然而，迄今为止的所有研究都依赖于p38MAPK的化学抑制剂（例如SB203580）的独家使用。由于这些抑制剂可能具有与p38MAPK无关的未知作用，因此我们对SB化合物靶向的VSMC中p38MAPK的主要亚型p38MAPK¿（MAPK14）进行了小干扰RNA敲低研究。与先前使用SB化合物的研究预测的抑制VSMC基因表达不同，我们发现MAPK14的敲低会刺激VSMC收缩基因的表达。通过几种明确的血管损伤模型，我们发现总MAPK14和磷酸化的MAPK14在血管壁的新内膜中富集，这表明MAPK14的表达在某种程度上与合成的VSMC表型有关。新的令人兴奋的数据显示，VSMC特异性Mapk14基因敲除小鼠表现出诱导的VSMC收缩基因表达，并且完全抵抗损伤诱导的新内膜形成。在机制上，我们发现MAPK14调节MRTFA核细胞质穿梭，这是srf依赖性VSMC收缩基因表达的关键决定因素。我们最近的研究发现，MAPK14的缺失上调了一种新的平滑肌和内皮细胞丰富的长链非编码RNA (SENCR)，这对VSMC收缩表型有积极影响。基于这些发现，我们提出了MAPK14通过失调MRTFA核易位和抑制senr来对抗VSMC收缩表型并促进血管疾病的全球假设。提出了三个相互关联的具体目标，以解决这一假设，使用新的小鼠模型和创新的概念。在Aim 1中，我们将阐明MAPK14在导致血管疾病的VSMC表型可塑性中的作用。在Aim 2中，我们将阐明MAPK14和MRTFA在调节VSMC分化中的综合作用。在Aim 3中，我们将阐明mapk14依赖性的SENCR抑制在VSMC中的调控和功能。总的来说，这些研究将阐明MAPK14在负调控VSMC分化中的重要作用，从而为VSMC表型的分子控制提供新的见解。这些研究也挑战了p38MAPK作为促vsmc分化信号通路的范式，并将该通路与两个关键下游靶点（MRTFA和senr）的拮抗联系起来。通过这些研究获得的信息对于设计对抗血管疾病的新策略具有有趣的治疗潜力。