Steroid Responsive Mechanisms in the Ear

描述（由申请人提供）：虽然糖皮质激素已用于控制听力损失数十年，但对其控制下的耳的细胞机制知之甚少。了解这些类固醇反应机制对于我们理解正常耳蜗功能以及设计适当的临床治疗至关重要。因此，本研究的长期目标是充分表征耳的类固醇驱动的细胞和分子机制。这项研究的进展表明，MRL/MpJ-Fas 1 pr自身免疫小鼠的听力损失通过糖皮质激素泼尼松龙和盐皮质激素醛固酮调节耳蜗基因表达来响应类固醇治疗。因此，我们的工作假设是，两种类固醇反应机制存在于耳：盐皮质激素受体介导的直接钠和钾转运（稳态）基因表达，和糖皮质激素受体介导的间接炎症基因抑制机制。计划中的研究将通过类固醇治疗来表征这些类固醇驱动的细胞和分子过程，这些类固醇治疗将选择性地分离这些受体并测量耳蜗稳态和炎症基因及其控制的蛋白质的变化。研究耳朵的这些类固醇机制的具体目的是： 目标1：确定盐皮质激素醛固酮和糖皮质激素泼尼松龙对内耳离子稳态和炎症基因表达的剂量依赖性控制。 目标二：确定最有效的控制内耳离子稳态和炎症基因表达过程的两种类固醇的组合剂量。 目的3：确定耳蜗的细胞和分子功能是由每个类固醇受体介导的。 目的4：确定是否有效的内耳稳态和抗炎基因的表达可以诱导中耳类固醇交付。 在所有研究中，1）将通过听性脑干反应测听来评估内耳功能。在某些实验中将测量耳蜗内电位。2)通过光学和电子显微镜评估内耳形态; 3）通过血清免疫复合物、血细胞比容和抗核抗体评估全身性自身免疫疾病; 4）通过ELISA评估耳蜗特异性自身抗体，和5）通过ELISA、Western印迹、细胞因子RNA表达和定量RT-PCR评估类固醇介导的耳蜗基因产物。这些研究的结果将提供关于类固醇控制下的耳朵的细胞和分子机制的新发现。这也将为开发比目前使用的更有效的类固醇疗法奠定重要基础。

DESCRIPTION (provided by applicant): Although glucocorticoids have been employed for decades for control of hearing loss, little is known of the cellular mechanisms of the ear that are under their control. Knowledge of these steroid-responsive mechanisms is critical for our understanding of normal cochlear function, as well as the design of appropriate clinical therapies. Therefore, the long term goal of this research is to fully characterize the steroid-driven cellular and molecular mechanisms of the ear. Progress on this study has shown that hearing loss in the MRL/MpJ-Fas1pr autoimmune mouse responds to steroid treatments by regulating cochlear gene expression with both the glucocorticoid prednisolone and the mineralocorticoid aldosterone. Therefore, our working hypothesis is that two steroid-responsive mechanisms exist in the ear: a direct sodium and potassium transport (homeostatic) gene expression mediated by the mineralocorticoid receptor, and an indirect inflammatory gene suppression mechanism mediated by the glucocorticoid receptor. The planned studies will characterize these steroid driven cellular and molecular processes with steroid treatments that will selectively isolate these receptors and measure changes in cochlear homeostatic and inflammatory genes and proteins they control. The specific aims to investigate these steroid mechanisms of the ear are: Aim 1: Determine the dose-dependent control of inner ear ion homeostatic and inflammatory gene expression by the mineralocorticoid aldosterone and the glucocorticoid prednisolone. Aim 2: Determine the most effective control of both inner ear ion homeostatic and inflammatory gene expression processes by combination doses of the two steroids. Aim 3: Determine which cochlear cellular and molecular functions are mediated by each steroid receptor. Aim 4: Determine if effective inner ear homeostatic and anti-inflammatory gene expression can be induced by middle ear steroid delivery. In all studies, 1) inner ear function will be assessed by auditory brainstem response audiometry. The endocochlear potential will be measured in some experiments. 2) inner ear morphology will be assessed by light and electron microscopy; 3) systemic autoimmune disease will be assessed by serum immune complexes, hematocrits, and antinuclear antibodies; 4) cochlear specific autoantibodies will be assessed with ELISA, and 5) steroid-mediated cochlear gene products will be assessed with ELISA, Western blot, cytokine RNA expression, and quantitative RT-PCR. The results from these studies will provide new findings regarding the cellular and molecular mechanisms of the ear that are under the control of steroids. This also will lay important groundwork for the potential development of steroid therapies more effective than those currently employed.