GRIA2, also known as Glutamate receptor, ionotropic, AMPA2 (alpha 2), encodes the GluA2 subunit of AMPA receptors (AMPARs). AMPARs are tetrameric ligand-gated channels, and GluA2 is crucial as post-transcriptional editing at the Q607 site makes heteromultimeric AMPARs Ca2+-impermeable, influencing current-voltage relationships. This gene is involved in glutamatergic synaptic transmission, which is vital for normal neural function [2].

In the context of diseases, GRIA2 has been implicated in multiple conditions. In lower extremity artery restenosis post-percutaneous transluminal angioplasty (PTA), GRIA2 is highly differentially expressed in restenotic arterial plaques. Its overexpression promotes the proliferation and migration of vascular smooth muscle cells (VSMCs) through upregulation of ENPP3, suggesting its role in the restenosis mechanism [1]. In neurodevelopmental disorders, heterozygous de novo GRIA2 mutations in patients can lead to intellectual disability (ID), autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). Functional expression studies show that these mutations decrease agonist-evoked current mediated by mutant subunits [2]. A novel de novo missense mutation in a patient with epilepsy, developmental delay, and failure to thrive led to a gain-of-function in GluA2-containing AMPARs, and the antiseizure drug perampanel was effective in treating the patient [4]. Also, a de novo missense variant in GRIA2 was found in a patient with epileptic encephalopathy, autism spectrum disorder, and global developmental delay [6]. In methamphetamine-use disorder, serum GRIA2 is higher in patients, and miR-181a acts as a negative regulator of GRIA2 [5]. Moreover, GRIA2 is a useful diagnostic marker for solitary fibrous tumour, with high expression in a large proportion of these tumours [3].

In conclusion, GRIA2 is essential for normal neural function through its role in glutamatergic synaptic transmission. Its dysregulation is associated with various diseases, including lower extremity artery restenosis, neurodevelopmental disorders, and methamphetamine-use disorder. The study of GRIA2 in these disease models helps in understanding the disease mechanisms and potentially developing new treatment strategies.

References:

1. Zhou, Mi, Qi, Lixing, Gu, Yongquan. 2021. GRIA2/ENPP3 Regulates the Proliferation and Migration of Vascular Smooth Muscle Cells in the Restenosis Process Post-PTA in Lower Extremity Arteries. In Frontiers in physiology, 12, 712400. doi:10.3389/fphys.2021.712400. https://pubmed.ncbi.nlm.nih.gov/34504438/

2. Salpietro, Vincenzo, Dixon, Christine L, Guo, Hui, Kullmann, Dimitri M, Houlden, Henry. 2019. AMPA receptor GluA2 subunit defects are a cause of neurodevelopmental disorders. In Nature communications, 10, 3094. doi:10.1038/s41467-019-10910-w. https://pubmed.ncbi.nlm.nih.gov/31300657/

3. Vivero, Marina, Doyle, Leona A, Fletcher, Christopher D M, Mertens, Fredrik, Hornick, Jason L. 2014. GRIA2 is a novel diagnostic marker for solitary fibrous tumour identified through gene expression profiling. In Histopathology, 65, 71-80. doi:10.1111/his.12377. https://pubmed.ncbi.nlm.nih.gov/24456377/

4. Coombs, Ian D, Ziobro, Julie, Krotov, Volodymyr, Cull-Candy, Stuart G, Farrant, Mark. 2022. A gain-of-function GRIA2 variant associated with neurodevelopmental delay and seizures: Functional characterization and targeted treatment. In Epilepsia, 63, e156-e163. doi:10.1111/epi.17419. https://pubmed.ncbi.nlm.nih.gov/36161652/

5. Zhang, Kai, Wang, Qingzhong, Jing, Xuxiu, Yu, Shunying, Zhao, Min. 2016. miR-181a is a negative regulator of GRIA2 in methamphetamine-use disorder. In Scientific reports, 6, 35691. doi:10.1038/srep35691. https://pubmed.ncbi.nlm.nih.gov/27767084/

6. Latsko, Maeson S, Koboldt, Daniel C, Franklin, Samuel J, White, Peter, Wilson, Richard K. 2022. De novo missense mutation in GRIA2 in a patient with global developmental delay, autism spectrum disorder, and epileptic encephalopathy. In Cold Spring Harbor molecular case studies, 8, . doi:10.1101/mcs.a006172. https://pubmed.ncbi.nlm.nih.gov/35534222/