Regulation of Mineralocorticoid Receptor Action

盐皮质激素受体作用的调节

• 批准号: 10436926
• 负责人: Celso Enrique Gomez-Sanchez
• 金额: --
• 依托单位: G V SONNY MONTGOMERY VA MEDCIAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10436926
• 关键词: Address; Affect; Affinity; Alcohol Oxidoreductases; Aldosterone; Amino Acids; Angiotensins; Antibodies; Area; Binding; Blood Pressure; Brain; CXCR3 gene; Cardiovascular system; Cell Line; Cells; Complications of Diabetes Mellitus; Congestive Heart Failure; Corticosterone; Cortisone; Cultured Cells; Dahl Hypertensive Rats; Data; Development; Diet; Distal; Dominant-Negative Mutation; Enzymes; Epithelial; Essential Hypertension; Gene Expression; Genomics; Glucocorticoid Receptor; Heart; Histocytochemistry; Hormones; Human; Hydrocortisone; Hydroxysteroid Dehydrogenases; Hyperaldosteronism; Hypertension; Immunofluorescence Immunologic; Intercalated Cell; Kidney; Ligand Binding Domain; Ligands; Luciferases; Measures; Mediating; Mineralocorticoid Receptor; Mouse Mammary Tumor Virus; Movement; Nephrons; Normal Range; Organ; Pathogenicity; Pathologic; Patients; Phosphorylation; Phosphotransferases; Plasma; Positioning Attribute; Post-Translational Protein Processing; Potassium; Protein Tyrosine Kinase; Rattus; Receptor Activation; Regulation; Reporter Genes; Reporting; Role; Serine; Site; Sleep Apnea Syndromes; Sodium; Sodium Chloride; Specificity; Steroids; System; TBK1 gene; Threonine; Time; Tissues; Transactivation; Water; cell type; inorganic phosphate; kidney cell; non-genomic; normotensive; overexpression; receptor; receptor binding; response; serine receptor; side effect; steroid hormone; transcription factor; vector

The mineralocorticoid receptor (MR) is a transcription factor expressed in many cells that regulates the expression of genes in involved myriad cell type-specific functions. Inappropriate activation of the MR causes hypertension and pathological tissue remodeling even in conditions of normal aldosterone levels. Activity of the MR is regulated by post-translational modifications including phosphorylation of serines and threonines. Phosphorylation activates or suppresses MR activity depending upon the amino acid involved. The kinase ULK1 was recently reported to phosphorylate serine 843 of the MR, thereby suppressing its activity, and to be expressed with the MR only in intercalated cells of the distal nephron. Our own specific antibodies reveal more extensive co-expression of ULK1 and MR in the kidney. ULK1 expression is widespread in the body and in multiple cell lines. Other kinases also have the potential to phosphorylate the MR at S843, thus inhibit MR activity. The MR has similar affinity for aldo, cortisol or corticosterone. Specificity for aldo is conferred by conversion of cortisol and corticosterone to the inactive cortisone and 11-dehydrocorticosterone by the 11β-hydroxysteroid dehydrogenase 2 (11-HSD2), however this enzyme is not present in most non-epithelial aldo target tissues. Cortisol and corticosterone are also converted to 20β-dihydro-cortisol and -corticosterone by carbonyl reductase 1 (Cbr1). We that found the 20β-dihydro metabolites do not activate the MR, thus providing an alternative mechanism for MR specificity for aldo where 11-HSD2 is not expressed. Hypotheses: 1) Phosphorylation of the MR at serine 843 is an important negative regulator of MR action that occurs in multiple tissues. 2) Reduction of the 20-keto of corticosterone and cortisol by carbonyl reductase 1 regulates ligand selectivity for the MR by converting corticosterone and cortisol into the inactive metabolites 20β-dihydrocorticosterone (20β-DHC) and 20β-dihydrocortisol. Both potentially modulate MR activity. Specific Aim 1: Study the role of phosphorylation of the MR at serine 843 (human) on genomic and non- genomic activity of the MR. Study the effects of over-expression and suppression of several kinases, ULK1, ULK2, TBK1, NEK2 and PAK1, with putative ability to phosphorylate the MR at S843 in cells expressing an MR reporter gene system. Study the distribution and co-localization of the MR with ULK1, ULK2 and other kinases that catalyze S843 phosphorylation in the kidney, heart, vessels and brain. Specific Aim 2: Study the role of the 20-keto reduction of cortisol and corticosterone on MR ligand selectivity. Determine the dynamics of the 20-keto reduction of corticosterone and cortisol by the human and rat Cbr1 in cells. Measure the conversion of corticosterone to 20β-dihydrocorticosterone in various tissues including in micropunches from specific areas of the rat brain where we demonstrate that Cbr1 and MR are co-expressed by immunofluorescent histochemistry. Measure plasma levels of corticosterone and 20β-DHC in plasma and tissues of rats fed different amounts of salt. The mechanisms for the cell-specific modulation of MR activity will never be known if not explored and are crucial for the development of rational therapy with minimal side effects for inappropriate MR activation.

矿物皮质激素受体（MR）是在许多调节的细胞中表达的转录因子 基因在涉及的无数细胞类型特异性功能中的表达。 MR原因的不当激活 即使在正常醛固酮水平的条件下，高血压和病理组织重塑也是如此。活动的活动 MR受翻译后修饰的调节，包括丝氨酸和苏氨酸的磷酸化。 磷酸化会根据所涉及的氨基酸而激活或抑制MR活性。激酶 最近，据报道，ULK1磷酸化MR的丝氨酸843，从而抑制其活性，并为 仅在远端肾小管的插入细胞中用MR表示。我们自己的特定抗体揭示了更多 肾脏中ULK1和MR的广泛共同表达。 ULK1表达在体内和 多个细胞系。其他激酶也有可能在S843处磷酸化MR，从而抑制MR 活动。 MR对Aldo，皮质醇或皮质酮具有相似的亲和力。阿尔多的特异性是通过转换而赋予的 11β-羟基类固醇的皮质醇和皮质酮与无活性可的松和11-氢化霉菌酮 脱氢酶2（11-HSD2），但是该酶在大多数非上皮aldo靶向时间内不存在。 皮质醇和皮质酮也被羰基转化为20β-二氢皮质醇和 - 皮质酮 还原酶1（CBR1）。发现20β-二氢代谢产物没有激活MR，因此提供了 Aldo的MR特异性的替代机制未表达11-HSD2。 假设：1）MR在丝氨酸843处的磷酸化是MR作用的重要负调节剂 发生多次。 2）减少羰基还原酶1酮皮质酮和皮质醇的20-酮1 通过将皮质酮和皮质醇转化为非活性代谢物，调节MR的配体选择性 20β-二合一皮质酮（20β-DHC）和20β-dihydrocortisol。两者都可能调节MR活性。 具体目标1：研究MR在丝氨酸843（人）基因组和非基因组中的磷酸化作用 MR的基因组活性。研究多种激酶ULK1的过表达和抑制的影响 ULK2，TBK1，NEK2和PAK1，具有表达MR的细胞中S843磷酸化MR的推定能力 记者基因系统。研究MR与ULK1，ULK2和其他激酶的分布和共定位 催化肾脏，心脏，血管和大脑中的S843磷酸化。 具体目标2：研究皮质醇和皮质酮20-酮降低对配体选择性的作用。 确定人和大鼠CBR1在中降低皮质酮和皮质醇的动力学的动力学 细胞。测量在包括在内 来自大鼠大脑特定区域的微置，我们证明了CBR1和MR共表达 通过免疫荧光组织化学。测量血浆中皮质酮和20β-DHC的血浆水平 大鼠的组织喂养不同量的盐。 如果未探索，将永远不会知道MR活性的细胞特异性调节机制 对于开发理性治疗至关重要的，对不适当的MR激活的副作用最小。