AUTHOR=Chen Sainan , Diao Jiale , Yue Zifan , Wei Ruili 

TITLE=Identification and validation of ferroptosis-related genes and immune cell infiltration in thyroid associated ophthalmopathy

JOURNAL=Frontiers in Genetics

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2023.1118391

DOI=10.3389/fgene.2023.1118391

ISSN=1664-8021

ABSTRACT=<p>Thyroid associated ophthalmopathy (TAO) is an orbital autoimmune inflammatory disease that is commonly associated with thyroid dysfunction. Although the etiology of TAO is unclear, ROS accumulation and oxidative stress have been closely linked to the pathogenesis of TAO. Ferroptosis is an iron-dependent programmed cell death characterized by intracellular labile iron levels, excessive accumulation of reactive oxygen species (ROS) and lipid peroxidation. Currently, there are few reports regarding the role of ferroptosis in TAO. This article aimed to identify ferroptosis-related genes (FRGs) with diagnostic and therapeutic potential in TAO and explore their relationship with immune cells and lncRNAs. GSE58331 was downloaded from Gene Expression Omnibus (GEO) database. A total of 162 DEGs were identified between 27 TAO samples and 22 health samples from GSE58331, among which six FRGs (<italic>CYBB, CTSB, SLC38A1, TLR4, PEX3</italic>, and <italic>ABCC1</italic>) were obtained. The AUC of <italic>SLC38A1, TLR4, PEX3</italic> in lacrimal gland tissues was greater than 80 which suggested high diagnostic value in TAO. The result of immune cell infiltrate analysis indicated increased infiltration of monocytes (<italic>p</italic> &lt; 0.001), macrophages M0(<italic>p</italic> = 0.039), mast cells activated (<italic>p</italic> = 0.008), and neutrophils (<italic>p</italic> = 0.045) in orbital tissues from TAO patients. Meanwhile, mast cells resting (<italic>p</italic> = 0.043) and macrophages M2 (<italic>p</italic> = 0.02) showed reduced infiltration in TAO samples. There were no gender differences in immune cell infiltration in the TAO patients. Two differentially expressed lncRNAs, <italic>LINC01140</italic> and <italic>ZFHX4-AS1</italic>, in TAO groups were identified as ferroptosis-related lncRNAs. <italic>CYBB-LINC01140-TLR4, CYBB- LINC01140- SLC38A1, TLR4- LINC01140- SLC38A1,</italic> and <italic>CTSB- ZFHX4-AS1- CYBB</italic> may be potential RNA regulatory pathways in TAO. Targeted drugs and transcription factors for differential expressed FRGs were also screened out in our study. <italic>In vitro,</italic> experiments revealed that <italic>CTSB, P</italic>EX3, ABC<italic>C1</italic> and <italic>ZFHX4-AS1(lncRNA)</italic> were differentially expressed in orbital fibroblasts (OFs) between TAO groups and healthy controls at the transcriptional level.</p>