CRISPR/Cas9 Mediated Therapeutic Approach in Huntington’s Disease

Abstract

The pathogenic mechanisms of these diseases must be well understood for the treatment of neurological disorders such as Huntington's disease. Huntington's Disease (HD), a dominant and neurodegenerative disease, is characterized by the CAG re-expansion that occurs in the gene encoding the polyglutamine-expanded mutant Huntingtin (mHTT) protein. Genome editing approaches include zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and Clustered Regularly Interspaced Short Palindromic Repeats/Caspase 9 (CRISPR/Cas9) systems. CRISPR/Cas9 technology allows effective gene editing in different cell types and organisms. Through these systems are created isogenic control of human origin induced pluripotent stem cells (iPSCs). In human and mouse models, HD-iPSC lines can be continuously corrected using these systems. HD-iPSCs can be corrected through the CRISPR/Cas9 system and the cut-and-paste mechanism using isogenic control iPSCs. This mechanism is a piggyBac transposon-based selection system that can effectively switch between vectors and chromosomes. In studies conducted, it has been determined that in neural cells derived from HD-iPSC, there are isogenic controls as corrected lines recovered from phenotypic abnormalities and gene expression changes. It has been determined that trinucleotide repeat disorders occurring in HD can be cured by single-guide RNA (sgRNA) and normal exogenous DNA restoration, known as the single guideline RNA specific to Cas9. The purpose of this review in addition to give general information about HD, a neurodegenerative disorder is to explained the role of CRISPR/Cas9 system with iPSCs in HD treatment.

Unraveling the Puzzle of Therapeutic Peptides: A Promising Frontier in Huntington’s Disease Treatment

“…Similarly, TALEN has been shown to modify the HTT gene in an allele-specific manner, reducing the expression of mHTT and aggregation in human HD fibroblasts . Several strategies are being employed to target mutated HTT mRNA, including RNA interference (RNAi), antisense oligonucleotide (ASO), and peptide nucleic acid (PNA) for preventing toxic neurodegeneration in HD . Of these approaches, ASOs show longer t 1/2 , enhanced bioavailability, and increased neuronal and glial uptake, thus are considered promising therapeutics to manage HD. ,, They are designed to specifically degrade the mHTT mRNA, preventing the production of mHTT.…”

“…36 RNAi is also used to partially degrade mutated HTT mRNA, which helps to reduce neuropathology, improve motor behavior, and increase viability in HD. 26 However, these approaches are marred by a continuous therapeutic expression for ameliorating HD. Interestingly, intrabody gene therapy ameliorates body weight, motor function, and cognitive and neuropathological manifestation in vivo.…”

“…These approaches follow different mechanisms for biding with mutated HTT DNA and have different modes of action. CRISPR technology is still in the preclinical stage of development and has several disadvantages, such as off-target effects, complex design, difficulties in administrating, and adverse neuroimmune responses. ,− Zinc finger proteins (ZFPs) reduce the expression of the mHTT gene at both the protein and mRNA levels . The expression of ZFP suppresses mHTT in the brain in an allele-selective manner, which reduces the mHTT protein aggregation and improves the neurobehavioral outcomes, such as rotarod performance and clasping in R6/2 mice .…”

“…However, the clinical trials of three HTT-lowering ASOs were recently suspended due to their off-target effects, failure to reduce the levels of mHTT in clinical settings, and worsened clinical outcomes. − PNAs are modified ASO that selectively inhibit mHTT in an allele-selective manner . RNAi is also used to partially degrade mutated HTT mRNA, which helps to reduce neuropathology, improve motor behavior, and increase viability in HD . However, these approaches are marred by a continuous therapeutic expression for ameliorating HD.…”

Curcumin-Based Nanomedicines in the Treatment of Inflammatory and Immunomodulated Diseases: An Evidence-Based Comprehensive Review

“…Theoretically, ND can be classified according to primary clinical signals such as dementia, motor neuron disease or parkinsonism, anatomic distribution of neurodegeneration such as frontotemporal degenerations, extrapyramidal disorders or spinocerebellar degenerations or, principally, ND can be classified as their molecular abnormality. Nowadays, the most popular ND are Alzheimer’s and Parkinson’s diseases [ 113 , 114 , 115 ].…”