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Diabetic retinopathy(DR)has been traditionally considered a purely microvascular disease in the retina. Currently, mainstream therapies focus only on advanced vascular complications and a single molecular target-vascular endothelial growth factor(VEGF). However, the research is shifting towards a more comprehensive view that DR is a neurovascular disease caused by neurovascular unit(NVU)injury. In the early stage of DR, diabetic retinal neurodegeneration(DRN)dominates and may precede the retinal microvascular abnormalities. Moreover, neuronal apoptosis can further lead to microvascular injury and blood-retinal barrier(BRB)disruption. Therefore, it makes sense to develop new therapeutic strategies to prevent or reverse DRN. However, no drug targeting DRN has been approved for clinical use. In recent years, it has become a trend to study the protective effect of traditional Chinese medicine on the retina. The primary research focuses on Chinese herb monomers. This article reviews the research status of representative monomers in DRN to provide references for the early treatment of DR and development of new drugs.

Previously, we described a large collection of Drosophila strains that each carry an artificial exon containing a T2AGAL4 cassette inserted in an intron of a target gene based on CRISPR-mediated homologous recombination. These alleles permit numerous applications and have proven to be very useful. Initially, the homologous recombination-based donor constructs had long homology arms (>500 bps) to promote precise integration of large constructs (>5 kb). Recently, we showed that in vivo linearization of the donor constructs enables insertion of large artificial exons in introns using short homology arms (100–200 bps). Shorter homology arms make it feasible to commercially synthesize homology donors and minimize the cloning steps for donor construct generation. Unfortunately, about 58% of Drosophila genes lack a suitable coding intron for integration of artificial exons in all of the annotated isoforms. Here, we report the development of new set of constructs that allow the replacement of the coding region of genes that lack suitable introns with a KozakGAL4 cassette, generating a knock-out/knock-in allele that expresses GAL4 similarly as the targeted gene. We also developed custom vector backbones to further facilitate and improve transgenesis. Synthesis of homology donor constructs in custom plasmid backbones that contain the target gene sgRNA obviates the need to inject a separate sgRNA plasmid and significantly increases the transgenesis efficiency. These upgrades will enable the targeting of nearly every fly gene, regardless of exon–intron structure, with a 70–80% success rate.