Unraveling the role of CACNA1F, RASAL1, GARIN4, and TRIM56 in common opioid side effects via transcriptomic analysis of differentiated neuron-like SH-SY5Y cells

Opioids remain indispensable for pain management but their use is limited by significant side effects, including respiratory depression, constipation, tolerance, addiction, and immunosuppression. Although much is known about their mechanism of action, the effects of acute opioid exposure on transcriptional responses have not yet been fully characterized. We performed a transcriptomic analysis of differentiated neuron-like SH-SY5Y cells exposed to five opioid ligands, namely, morphine, TRV130, metamorphine, β-endorphin, and naloxone. After incubation for 15 minutes, the cells were harvested and processed for RNA sequencing via the Illumina NovaSeq 6000 platform. Differential gene expression analysis was performed with DESeq2, and pathway enrichment was conducted via GO, KEGG and Reactome. Individual comparisons between each opioid-treated group and the control group revealed no statistically significant transcriptional changes. However, when all the agonist-treated samples were pooled and compared with the control samples, we identified several significantly downregulated genes (adjusted p < 0.05). Specifically, we observed alterations in the expression of the genes CACNA1F, RASAL1, GARIN4, and TRIM56, which are involved in calcium signaling, synaptic plasticity, the immune response, and reproductive function. CACNA1F downregulation may affect neuronal excitability and retinal signaling; RASAL1 suppression could impact synaptic maturation and memory; GARIN4 is associated with sperm morphology; and TRIM56 downregulation has an immunomodulatory effect, all of which aligns with known opioid-induced side effects. Our findings demonstrate that even short-term opioid exposure can initiate subtle but functionally relevant transcriptional changes. These early responses highlight the potential of transcriptomic profiling to uncover the molecular mechanisms underlying opioid pharmacodynamics and side effects. This approach offers deeper insights into opioid action and supports the development of safer analgesics with fewer systemic adverse effects.