# Exosomal circ_0093708 as a potential ferroptosis biomarker in cerebral ischemia–reperfusion injury

## TL;DR

This study identifies exosomal circ_0093708 as a potential biomarker for ferroptosis in cerebral ischemia–reperfusion injury, offering new diagnostic and therapeutic insights.

## Contribution

The study introduces exosomal circ_0093708 as a novel ferroptosis biomarker in cerebral ischemia–reperfusion injury.

## Key findings

- Exosomal circ_0093708 shows high diagnostic accuracy (AUC = 0.93) for ferroptosis in cerebral ischemia–reperfusion injury.
- DUSP1 is upregulated during ferroptosis and its inhibition aggravates the condition.
- Circ_0093708 interacts with miR-101-3p and DUSP1, suggesting a regulatory role in ferroptosis.

## Abstract

Ferroptosis plays a critical role in neuronal injury following cerebral infarction. However, effective therapeutic strategies targeting ferroptosis after cerebral ischemia–reperfusion injury (CI/RI) remain limited. Exosome-based therapy holds significant promise in this context. This study aims to identify key exosomal markers of ferroptosis.

By integrating and analyzing multiple GSE datasets, we identified ferroptosis-associated key genes. These findings were further validated in external databases, cellular models, and animal experiments using malondialdehyde (MDA), glutathione (GSH), iron, reactive oxygen species (ROS) assays, qRT-PCR, Western blotting. By further establishing a ferroptosis model and inhibiting DUSP1 with drugs, we further explored the potential function of DUSP1 in ferroptosis. The role of miR-101-3p was assessed in CI/RI models, while the diagnostic value of exosomal circular RNA was evaluated using receiver operating characteristic curve analysis.

Combined differential analysis revealed PTGS2 and DUSP1 as ferroptosis-associated genes potentially regulated by exosomal circRNAs. In cellular and animal models, ferroptosis post-CI/RI was confirmed by elevated MDA, iron, and ROS levels, alongside reduced GSH. DUSP1 expression was significantly upregulated during ferroptosis, as demonstrated by qRT-PCR, Western blotting, and immunofluorescence. In the simple ferroptosis model, the expression of DUSP1 increases and inhibiting DUSP1 can aggravate ferroptosis. Conversely, miR-101-3p was downregulated in CI/RI, consistent with database predictions. Notably, exosomal circ_0093708 exhibited high diagnostic accuracy (Area under the curve = 0.93, sensitivity = 90%, specificity = 90%). Bioinformatics analysis suggested binding interactions among circ_0093708, miR-101-3p, and DUSP1.

Exosomal circ_0093708 is linked to DUSP1 and PTGS2 expression by sponging miR-101-3p, positioning it as a potential biomarker for ferroptosis in CI/RI.