SLC40A1 Mediates Ferroptosis and Cognitive Dysfunction in Type 1 Diabetes

Cognitive dysfunction often accompanies diabetes. Both hypoglycemia and hyperglycemia cause cognitive dysfunctions. However, the underlying pathophysiology remains unclear. Recent evidence show that ferroptosis primarily triggers nerve cell death, Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). The present study aimed to investigate whether ferroptosis is a vital pathogenic pathway in diabetes-induced cognitive dysfunction. Type 1 diabetic rat model was created by intraperitoneal injection of streptozotocin (STZ). Significant cognitive dysfunction was observed in the diabetic rats as evidenced by increase in latency period to find a hidden platform and decreased cumulative time spent in the target quadrant (TQ) in the Morris water maze test. We detected the amplitude of low-frequency fluctuation (ALFF) of the BOLD (Blood Oxygenation Level-Dependent) signal using resting-state functional magnetic resonance imaging (rs-fMRI). Consequently, we found that the ALFF values, as well as the T2 relaxation time of the bilateral hippocampus, were reduced in Type 1 diabetic rats. We detected Fe²⁺ level and lipid peroxidation products (malondialdehyde (MDA) and 4-Hydroxynonenal (4-HNE)) in the hippocampus. Mitochondria and neuron injury in the STZ-induced diabetic rats were determined using a Transmission Electron Microscope and Nissl body staining. Iron overload and ferroptosis were detected in the hippocampus. Furthermore, mRNA microarray analysis revealed 201 dysregulated mRNAs in STZ-induced type 1 diabetes (T1D). Pathway enrichment analyses indicated that differentially expressed mRNAs associated-coding genes were associated with ferroptosis. Among ferroptosis signaling pathway genes, Slc40a1 gene (ferroportin) was downregulated. We show that ferroptosis is associated with diabetic cognitive dysfunction and Slc40a1 mediates ferroptosis in T1D.