The neurodevelopmental regulatory role and clinical value of hsa-circ-CORO1C–hsa-miR-708-3p–JARID2 + LNPEP axis in early-onset schizophrenia

Genes discovered by previous epigenetic studies of schizophrenia have focused solely on diagnostics or pathology, potentially leading to a disconnection between them. Using these molecules to identify the disease is considered insufficient. MicroRNAs (miRNAs) binding to messenger RNAs (mRNAs) can lead to mRNA degradation, while circular RNAs (circRNAs), by binding to miRNAs as sponge, can reduce the inhibitory effect of miRNAs on mRNAs. CircRNAs, miRNAs, and mRNAs form the multi-molecular axis that can bind and regulate expression between each other, thereby affecting biological function. This study focused on early-onset schizophrenia (EOS), aiming to identify the multi-molecular axis consisting of circRNAs, miRNAs, and mRNAs with both neurobiological function and diagnostic value to assist in disease identification. In the discovery cohort of 10 drug-naïve, first-episode patients with EOS and 10 matched healthy controls (HCs), differentially expressed (DE) circRNAs and miRNAs were identified via Illumina high-throughput sequencing. In the validation cohort-1 (40 EOS v.s. 50 HCs), the candidate circRNAs and miRNAs were further screened using Real-time polymerase chain reaction, Sanger sequencing, and RNase R assay. Combining dual-luciferase reporter assay with overexpression/knockdown experiments, the axis consisting of circRNAs-miRNAs-mRNAs with binding and regulatory relationships has been established. Subsequently, the functions of genes on the axis were explored through zebrafish embryo manipulation and neural differentiation. The clinical value of the entire axis was assessed in the validation cohort-2 (84 EOS v.s. 67 HCs). Patients with EOS exhibited expression profiles of 487 DE circRNAs and 101 DE miRNAs compared to HCs. The binding relationships and regulatory effects of hsa-circ-CORO1C on hsa-miR-708-3p, hsa-miR-708-3p on target JARID2 and LNPEP were elucidated. Among them, hsa-miR-708-3p caused aberrant phenotypes including significant craniocerebral malformation and impaired neuron axon growth. JARID2 and LNPEP could facilitate neuronal differentiation and augment synaptic formation. In addition to their neurobiological functions, the combined diagnostic efficacy of the whole axis, where hsa-circ-CORO1C could serve as a sponge for hsa-miR-708-3p to alleviate its suppressive effects on JARID2 and LNPEP, surpassed any individual gene we found in EOS. Our study demonstrated a multi-molecular axis, hsa-circ-CORO1C-hsa-miR-708-3p-JARID2 + LNPEP, in EOS for the first time. By integrating evidence from genetic, neurophenotypic, and clinical perspectives, we have expanded the comprehension of the pathological mechanism and provided the reference for identifying reliable objective diagnostic biomarkers for EOS.