LOSS OF GLIA-ENRICHED LONG NON-CODING RNA INFLUENCES THE GLUTAMATERGIC SYNAPSES

The vast majority of the human genome consists of non-coding regions, including various types of non-coding RNAs (ncRNAs). In this study, we focused on the characterization of long non-coding RNAs (lncRNAs) that are highly expressed in the central nervous system (CNS). Using in-house single-cell RNA-seq data from the human prefrontal cortex and the RNA Atlas, we identified a novel lncRNA “Cns-lnc”.

Cns-lnc has a conserved mouse homolog, and RT-qPCR analysis across adult mouse organs and brain regions revealed CNS-specific expression, with highest levels in the cortex. Notably, Cns-lnc expression decreases with aging in mice. Subcellular localization analysis showed predominant nuclear localization, suggesting a regulatory role in gene expression. In vitro experiments further demonstrated that Cns-lnc is highly expressed in primary cortical astrocytes. Knockdown of Cns-lnc in primary mouse cortical astrocytes led to upregulation of immune response–related genes and downregulation of genes involved in astrocytic synaptic support and nervous system development. Functionally, Cns-lnc knockdown reduced the expression of glutamate transporters at both mRNA and protein levels, resulting in impaired glutamate uptake. In addition, knockdown decreased the mRNA expression of NMDA receptor subunits, leading to attenuated glutamate-induced NMDA receptor–mediated calcium signaling. Consistently, co-culture of primary mouse cortical neurons with Cns-lnc–deficient astrocytes increased neuronal activity, while glutamate-induced toxicity did not affect neuronal viability.

Overall, our findings highlight Cns-lnc as an important regulator of astrocyte function at glutamatergic synapses, with potential implications for synaptic regulation in the adult brain.