ABSTRACT
Catalytically inactive dCas9 fused to transcriptional activators (dCas9-VPR) enables activation of silent genes. Many disease genes have counterparts, which serve similar functions but are expressed in distinct cell types. One attractive option to compensate for the missing function of a defective gene could be to transcriptionally activate its functionally equivalent counterpart via dCas9-VPR. Key challenges of this approach include the delivery of dCas9-VPR, activation efficiency, long-term expression of the target gene, and adverse effects in vivo. Using dual adeno-associated viral vectors expressing split dCas9-VPR, we show efficient transcriptional activation and long-term expression of cone photoreceptor-specific M-opsin (Opn1mw) in a rhodopsin-deficient mouse model for retinitis pigmentosa. One year after treatment, this approach yields improved retinal function and attenuated retinal degeneration with no apparent adverse effects. Our study demonstrates that dCas9-VPR-mediated transcriptional activation of functionally equivalent genes has great potential for the treatment of genetic disorders.
Subject(s)
CRISPR-Cas Systems , Genetic Therapy , Animals , Blindness/genetics , Blindness/therapy , Mice , Transcription Factors/genetics , Transcriptional ActivationABSTRACT
One major obstacle in cancer therapy is chemoresistance leading to tumor recurrence and metastasis. Cancer stem cells, in particular glioblastoma stem cells, are highly resistant to chemotherapy, radiation, and immune recognition. In case of immune recognition, several survival mechanisms including, regulation of autophagy, proteases, and cell surface major histocompatibility complex class I molecules, are found in glioblastoma stem cells. In different pathways, cathepsins play a crucial role in processing functional proteins that are necessary for several processes and proper cell function. Consequently, strategies targeting these pathways in glioblastoma stem cells are promising approaches to interfere with tumor cell survival and will be discussed in this review.
