NR1H2,也称为LXRβ(肝脏X受体β),是一种重要的核受体,属于核受体超家族。NR1H2基因编码的蛋白质是胆固醇代谢的关键调节因子,它在维持细胞内胆固醇平衡方面发挥着重要作用。NR1H2与LXRα(肝脏X受体α,由NR1H3基因编码)共同组成肝脏X受体(LXR)家族,两者在细胞中表达不同,LXRα主要在代谢活跃的组织中表达,而LXRβ则更为广泛地表达。
LXRβ是一种配体依赖性转录因子,可以被内源性的氧化胆固醇代谢产物(如24-羟基胆固醇、25-羟基胆固醇和27-羟基胆固醇)激活。当细胞内胆固醇水平升高时,LXRβ与这些氧化胆固醇结合,形成LXRβ/retinoid X receptor(RXR)异源二聚体,进而结合到DNA上的LXR反应元件(LXRE),激活下游基因的转录。这些下游基因参与胆固醇的摄取、代谢、排泄以及胆汁酸的合成等过程,从而降低细胞内的胆固醇水平,维持胆固醇的动态平衡。
NR1H2基因的遗传变异与多种疾病的发生发展密切相关。例如,NR1H2基因的变异与阿尔茨海默病的发生风险相关[1]。NR1H2基因的变异还与胰岛素分泌异常相关,这可能会增加患2型糖尿病的风险[2,3]。此外,NR1H2基因的变异还与妊娠并发症——子痫前症的发生相关[4]。NR1H2基因的变异还可能影响男性生育能力[5]。
NR1H2基因的变异还可能影响脑胆固醇代谢和神经元发育,这可能与自闭症谱系障碍(ASD)的发生相关[6]。NR1H2基因的变异还可能影响鸟类的内分泌功能[7]。NR1H2基因的变异还可能影响膀胱外翻-尿道上裂复合征(BEEC)的发生[8]。
NR1H2基因的研究为理解胆固醇代谢的生物学功能和疾病发生机制提供了重要的线索。NR1H2基因的研究也为治疗和预防与胆固醇代谢相关的疾病提供了新的思路和策略。
参考文献:
1. Adighibe, Omanma, Arepalli, Sampath, Duckworth, Jaime, Hardy, John, Wavrant-De Vrièze, Fabienne. 2005. Genetic variability at the LXR gene (NR1H2) may contribute to the risk of Alzheimer's disease. In Neurobiology of aging, 27, 1431-4. doi:. https://pubmed.ncbi.nlm.nih.gov/16207502/
2. Ketterer, Caroline, Müssig, Karsten, Machicao, Fausto, Häring, Hans-Ulrich, Staiger, Harald. 2010. Genetic variation within the NR1H2 gene encoding liver X receptor β associates with insulin secretion in subjects at increased risk for type 2 diabetes. In Journal of molecular medicine (Berlin, Germany), 89, 75-81. doi:10.1007/s00109-010-0687-1. https://pubmed.ncbi.nlm.nih.gov/21042792/
3. Sadeghi, Mohammad Bagher, Nakhaee, Alireza, Saravani, Ramin, Sargazi, Saman. 2021. Significant association of LXRβ (NR1H2) polymorphisms (rs28514894, rs2303044) with type 2 diabetes mellitus and laboratory characteristics. In Journal of diabetes and metabolic disorders, 20, 261-270. doi:10.1007/s40200-021-00740-3. https://pubmed.ncbi.nlm.nih.gov/34178836/
4. Mouzat, Kevin, Mercier, Eric, Polge, Anne, Lumbroso, Serge, Gris, Jean-Christophe. 2011. A common polymorphism in NR1H2 (LXRbeta) is associated with preeclampsia. In BMC medical genetics, 12, 145. doi:10.1186/1471-2350-12-145. https://pubmed.ncbi.nlm.nih.gov/22029530/
5. Shi, Rui, Li, Yingmin, Zhu, Weihao, Cong, Bin, Shi, Weibo. 2024. The Regulation of Frontal Cortex Cholesterol Metabolism Abnormalities by NR3C1/NRIP1/NR1H2 Is Involved in the Occurrence of Stress-Induced Depression. In International journal of molecular sciences, 25, . doi:10.3390/ijms25158075. https://pubmed.ncbi.nlm.nih.gov/39125645/
6. Jarvis, Sheba, Williamson, Catherine, Bevan, Charlotte L. 2019. Liver X Receptors and Male (In)fertility. In International journal of molecular sciences, 20, . doi:10.3390/ijms20215379. https://pubmed.ncbi.nlm.nih.gov/31671745/
7. Menteşe Babayiğit, Tuğba, Gümüş-Akay, Güvem, Uytun, Merve Çikili, Yürümez, Esra, Öztop, Didem Behice. 2024. Investigation of Liver X Receptor Gene Variants and Oxysterol Dysregulation in Autism Spectrum Disorder. In Children (Basel, Switzerland), 11, . doi:10.3390/children11050551. https://pubmed.ncbi.nlm.nih.gov/38790546/
8. Köllges, Ricarda, Stegmann, Jil, Schneider, Sophia, Ludwig, Kerstin U, Reutter, Heiko. 2023. Exome Survey and Candidate Gene Re-Sequencing Identifies Novel Exstrophy Candidate Genes and Implicates LZTR1 in Disease Formation. In Biomolecules, 13, . doi:10.3390/biom13071117. https://pubmed.ncbi.nlm.nih.gov/37509153/