Emerging CRISPR Therapies for Precision Gene Editing and Modulation in the Cardiovascular Clinic.

Purpose Of Review: Outline the growing suite of novel genome editing tools powered by CRISPR-Cas9 technology that are rapidly advancing towards the clinic for the treatment of cardiovascular disorders.

Recent Findings: A diversity of new genome editors and modulators are being developed for therapies across myriad human diseases. Recent breakthroughs have improved the efficacy, safety, specificity, and delivery of CRISPR-mediated therapies that could impact heart disease in the next decade, though several challenges remain.

TRP Channels in Excitotoxicity.

Glutamate excitotoxicity is a central mechanism contributing to cellular dysfunction and death in various neurological disorders and diseases, such as stroke, traumatic brain injury, epilepsy, schizophrenia, addiction, mood disorders, Huntington's disease, Alzheimer's disease, Parkinson's disease, multiple sclerosis, pathologic pain, and even normal aging-related changes. This detrimental effect emerges from glutamate binding to glutamate receptors, including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, -methyl-d-aspartate receptors, kainate receptors, and GluD receptors. Thus, excitotoxicity could be prevented by targeting glutamate receptors and their downstream signaling pathways.

CRISPR Activation Reverses Haploinsufficiency and Functional Deficits Caused by Truncation Variants.

Background: truncation variants (TTNtvs) are the most common genetic lesion identified in individuals with dilated cardiomyopathy, a disease with high morbidity and mortality rates. TTNtvs reduce normal TTN (titin) protein levels, produce truncated proteins, and impair sarcomere content and function. Therapeutics targeting TTNtvs have been elusive because of the immense size of TTN, the rarity of specific TTNtvs, and incomplete knowledge of TTNtv pathogenicity.

Reading Frame Repair of Truncation Variants Restores Titin Quantity and Functions.

Background: Titin truncation variants (TTNtvs) are the most common inheritable risk factor for dilated cardiomyopathy (DCM), a disease with high morbidity and mortality. The pathogenicity of TTNtvs has been associated with structural localization as A-band variants overlapping myosin heavy chain-binding domains are more pathogenic than I-band variants by incompletely understood mechanisms. Demonstrating why A-band variants are highly pathogenic for DCM could reveal new insights into DCM pathogenesis, titin (TTN) functions, and therapeutic targets.

Actinin BioID reveals sarcomere crosstalk with oxidative metabolism through interactions with IGF2BP2.

Actinins are strain-sensing actin cross-linkers that are ubiquitously expressed and harbor mutations in human diseases. We utilize CRISPR, pluripotent stem cells, and BioID to study actinin interactomes in human cardiomyocytes. We identify 324 actinin proximity partners, including those that are dependent on sarcomere assembly.

Development of a Cardiac Sarcomere Functional Genomics Platform to Enable Scalable Interrogation of Human Variants.

Background: Pathogenic variants are a cause of hypertrophic and dilated cardiomyopathies, which promote heart failure by incompletely understood mechanisms. The precise functional significance for 87% of variants remains undetermined, in part, because of a lack of functional genomics studies. The knowledge of which and how variants cause hypertrophic and dilated cardiomyopathies could improve heart failure risk determination, treatment efficacy, and therapeutic discovery, and provide new insights into cardiomyopathy pathogenesis, as well.