Cortex Dictamni induces retinitis pigmentosa in zebrafish by inhibiting pde6a post-transcriptional activity via mmu-mir-6240-p3_2

Ethnopharmacological relevance: Cortex Dictamni (CD) is the dried root skin of Dictamnus dasycarpus Turcz, widely used in the field of traditional Chinese medicine. mainly for the treatment of skin diseases. Recent adverse reactions to CD limited the clinical application in combination with other traditional Chinese medicines.Aim of the study: To investigate the retinitis pigmentosa (RP) effects of CD using the zebrafish model and elucidate the underlying molecular mechanism of CD-induced RP in zebrafish.Materials and methods: The 3-dpf zebrafish larvae were divided into control and CD group. RNA sequencing followed, with qRT-PCR validating miRNAs and mRNAs. Dual luciferase reporter assay confirmed mmu-mir-6240-p3_2's interaction with pde6a. HT22 cells were transfected, treated with CD, and evaluated for migration, invasion, malondialdehyde level, superoxide dismutase and acetylcholine activities.Results: The results showed 6228 differentially expressed genes and 66 miRNAs differentially expressed in zebrafish exposed to CD. The personal correlation coefficient results showed that mmu-mir-6240-p3_2 had the highest correlation coefficient with pde6a and had a negative regulatory relationship. The results of dual luciferase reporter gene further showed that pde6a gene was the direct target of mmu-mir-6240-p3_2. Cell experiment results showed that inhibiting mir-6240-p3_2 can upregulate pde6a expression, alleviate HT22 cell injury, and reverse the inhibition of cell migration and invasion induced by CD.Conclusions: CD induces RP in zebrafish by inhibiting pde6a post-transcriptional activity via mmu-mir-6240-p3_2. These findings have important implications for understanding the potential side effects of CD and for developing safer therapeutic strategies involving traditional Chinese medicines.