Mechanisms of Altered Gastrointestinal Dysfunction

胃肠功能障碍的改变机制

• 批准号: 8732649
• 负责人: George Nicholas Verne
• 金额: $ 33.71万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8732649
• 关键词: Abdominal Pain; Biological; Biological Factors; Colon; Constipation; Development; Diarrhea; Disease; Down-Regulation; Epigenetic Process; Figs - dietary; Fluorescent in Situ Hybridization; Functional disorder; Gene Targeting; Genes; Glutamate Receptor; Glutamates; Goals; Hypersensitivity; Intestines; Intrathecal Injections; Irritable Bowel Syndrome; Knowledge; Lead; Methods; MicroRNAs; Modeling; N-Methyl-D-Aspartate Receptors; Neurotransmitters; Nociception; Nociceptive Stimulus; Oligonucleotide Probes; Oligonucleotides; Opioid; Opioid Receptor; Pain; Pathway interactions; Patients; Pharmaceutical Preparations; Process; Property; Rattus; Receptor Signaling; Role; Signal Pathway; Signal Transduction; Stimulus; Stream; Symptoms; Technology; Testing; Therapeutic; Tissues; United States National Institutes of Health; Up-Regulation; Visceral; base; chronic abdominal pain; chronic pain; follow-up; gastrointestinal; glutamine receptor; in vivo; inhibitor/antagonist; innovation; locked nucleic acid; novel therapeutic intervention; public health relevance; receptor; receptor expression; relating to nervous system; translational study

DESCRIPTION (provided by applicant): Patients with irritable bowel syndrome (IBS) suffer from chronic abdominal pain and associated GI symptoms - diarrhea, constipation, bloating & urgency. Those with severe symptoms may also have visceral hypersensitivity to nociceptive stimuli, suggesting aberrant neural pain processing mechanisms. Indeed, we found a significant subset (~35%) of IBS patients with visceral hypersensitivity to noxious experimental stimuli (e.g., colonic distension); but the mechanism was unclear. We found a clue to that mechanism during our previous NIH-supported study (R01NS053090); we identified unique microRNAs (miRNAs) in colon tissues of this subset. Here we will follow up on that clue by testing the following hypothesis: Aberrant expression of key miRNAs dysregulates expression of downstream miRNA targets (opioid receptors; NMDA receptors) which contributes to visceral hypersensitivity in IBS patients. To determine the intra- and inter-cellular roles of unique miRNAs in the epigenetic regulation of down- stream receptor target genes, our lab has developed innovative methods. These methods combine unique miRNA recognition properties of locked nucleic acid (LNA) modified oligonucleotide probes with fluorescence in situ hybridization (FISH) using tyramide signal amplification (TSA) technology. We will use in vivo intrathecal injection of miRNA inhibitors (LNAs) or miRNA mimics (precursors) to experimentally regulate expression of specific miRNAs that target opioid (Aim 1) and glutamate (Aim 2) receptors in our validated rat model of visceral hypersensitivity (Zhou et al., Pain, 2008). Thus, we will use a combination of strategies to develop a comprehensive high-confidence model of miRNA targeting networks for opioid and glutamine receptors. In Aim 1 we will determine whether increased miR-29a/b cluster and miR-29b-1-5p expression enhances visceral hypersensitivity via downregulation of opioid signaling pathways. In Aim 2, we will determine whether decreased miR-23a/b cluster and 125b-1-3p expression facilitates visceral hypersensitivity via upregulation of glutamate signaling mechanisms. Our proposed studies should identify critical contributions of aberrantly expressed miRNAs that target downstream opioid and glutamate receptors in intestinal tissues of IBS patients with visceral hypersensitivity This will bridge an important gap in our knowledge of the underlying mechanisms of dysregulation of nociceptive pathways that lead to chronic pain and altered visceral nociception in patients who suffer from common functional GI disorders. More importantly, the results should lead to the development of innovative therapeutic strategies via development of synthesized oligonucleotides that inhibit or mimic specific miRNAs that modulate epigenetic regulation of down-stream target genes (e.g. opioid or glutamate receptors) that drive visceral nociception. The ultimate goal of the proposed translational studies is to develop new therapies for treating our patients with IBS and other functional GI disorders.

描述（由申请人提供）：肠易激综合症（IBS）患者患有慢性腹痛和相关胃肠道症状 - 腹泻、便秘、腹胀和尿急。那些症状严重的人也可能对伤害性刺激有内脏过敏反应，这表明神经疼痛处理机制存在异常。事实上，我们发现 IBS 患者中有一个显着的子集（约 35%）对有害实验刺激（例如结肠扩张）内脏过敏；但其机制尚不清楚。我们在之前 NIH 支持的研究 (R01NS053090) 中发现了该机制的线索；我们在这个亚群的结肠组织中鉴定出了独特的 microRNA (miRNA)。在这里，我们将通过测试以下假设来追踪这一线索：关键 miRNA 的异常表达会失调下游 miRNA 靶标（阿片受体；NMDA 受体）的表达，从而导致 IBS 患者内脏过敏。 为了确定独特 miRNA 在下游受体靶基因表观遗传调控中的细胞内和细胞间作用，我们的实验室开发了创新方法。这些方法将锁核酸 (LNA) 修饰的寡核苷酸探针的独特 miRNA 识别特性与使用酪酰胺信号放大 (TSA) 技术的荧光原位杂交 (FISH) 相结合。我们将在体内鞘内注射 miRNA 抑制剂 (LNA) 或 miRNA 模拟物（前体），通过实验调节在我们经过验证的内脏超敏反应大鼠模型中靶向阿片类药物 (Aim 1) 和谷氨酸 (Aim 2) 受体的特定 miRNA 的表达 (Zhou et al., Pain, 2008)。因此，我们将采用多种策略组合来开发针对阿片类药物和谷氨酰胺受体的 miRNA 靶向网络的综合高置信度模型。 在目标 1 中，我们将确定 miR-29a/b 簇和 miR-29b-1-5p 表达的增加是否通过下调阿片类信号通路来增强内脏超敏反应。在目标 2 中，我们将确定 miR-23a/b 簇和 125b-1-3p 表达的减少是否通过谷氨酸信号传导机制的上调促进内脏过敏。我们提出的研究应该确定异常表达的 miRNA 的关键作用，这些 miRNA 靶向内脏过敏性肠易激综合征患者肠道组织中的下游阿片类药物和谷氨酸受体。这将弥补我们对伤害性途径失调的潜在机制的认识上的一个重要空白，这些机制导致患有常见功能性胃肠道疾病的患者发生慢性疼痛和内脏伤害性感受改变。更重要的是，这些结果应该通过开发合成寡核苷酸来开发创新的治疗策略，这些寡核苷酸抑制或模拟特定的 miRNA，调节驱动内脏伤害感受的下游靶基因（例如阿片类药物或谷氨酸受体）的表观遗传调控。拟议转化研究的最终目标是开发新疗法来治疗肠易激综合症和其他功能性胃肠道疾病患者。