CRISPR-Cas Epigenetic Editing

CRISPR-Cas epigenetic editing is a modified form of CRISPR genome editing technology designed to modify the epigenome rather than the genome. The CRISPR-Cas systems used for epigenetic editing affect gene expression without cutting DNA.

Epigenetic editing, also referred to as epigenome editing or epigenome engineering, is the targeted modification of epigenetic marks on DNA and histones, often with the goal of changing the transcription level of a gene or genes. Epigenetic marks such as DNA methylation and histone acetylation contribute to transcriptional regulation, are maintained through cell division and form a cellular memory of transcriptional states.

CRISPR-Cas epigenetic editing is a modified form of the genome editing platform, such as a version of CRISPR-Cas9 that does not cut DNA but affects gene expression levels. Gene expression levels depend on DNA methylation levels and whether chromatin conformation is in an active or repressed state. Epigenetic editing, also referred to as epigenome editing or epigenome engineering, is the targeted modification of epigenetic marks on DNA and histones, often with the goal of changing the transcription level of a gene or genes. Epigenetic marks such as DNA methylation and histone acetylation contribute to transcriptional regulation, are maintained through cell division and form a cellular memory of transcriptional states. Epigenetic editing with CRISPR-Cas9CRISPR-Cas9 uses the nuclease dead Cas9 (dCas9) to target the genome and instead of altering the genetic sequence, the system alters the epigenome by bringing transcriptional activators, repressors and chromatin modifiers to the desired genomic region. This technique allows researchers to study how epigenetic marks like DNA methylation, histone acetylation and chromatin modifier proteins affect gene expression in cultured mammalian cells and live mice . Programmable gene regulation via CRISPR-Cas epigenetic editing has potential clinical applications .

Chroma Medicine, based on MIT research, aims to treat diseases and complex conditions. The company developed an epigenetic editor that represses the expression of PCSK9, a key target gene for treatment of hypercholesterolemia. Chroma is also using epigenetic editors for multiplexed editing in healthy donor-derived T cells.

Tune Therapeutics uses their platform, TEMPO, comprised of a target (dCas9) and an effector module which can be varied in an iterative process to fine tune gene expression. The company uses TEMPO in drug discovery and selection, screening for activators or repressors of gene expression in a variety of cells types and disease states. Tune maintains collaborations with Duke University. The company reported repressed transcription of PCSK9 which resulted in lower LDL cholesterol in Non-Human Primates. Tune reported that epigenetic modifications to CAR T-cells which target HER2 enhanced their activity against solid tumors in engrafted mice.

CRISPR-Cas9CRISPR-Cas epigenetic editing is a modified form of the genome editing platform, such as a version of CRISPR-Cas9 that does not cut DNA but affects gene expression levels. Gene expression levels depend on DNA methylation levels and whether chromatin conformation is in an active or repressed state. Epigenetic editing, also referred to as epigenome editing or epigenome engineering, is the targeted modification of epigenetic marks on DNA and histones, often with the goal of changing the transcription level of a gene or genes. Epigenetic marks such as DNA methylation and histone acetylation contribute to transcriptional regulation, are maintained through cell division and form a cellular memory of transcriptional states. Epigenetic editing with CRISPR-Cas9 uses the nuclease dead Cas9 (dCas9) to target the genome and instead of altering the genetic sequence, the system alters the epigenome by bringing transcriptional activators, repressors and chromatin modifiers to the desired genomic region. This technique allows researchers to study how epigenetic marks like DNA methylation, histone acetylation and chromatin modifier proteins affect gene expression in cultured mammalian cells and live mice . Programmable gene regulation via CRISPR-Cas9CRISPR-Cas epigenetic editing has potential clinical applications .

Epic Bio (Epicrispr Biotechnologies) used their GEMS platform to develop a potential treatment for FSHD, EPI-321 has a catalytically inactive Cas protein fused to gene-suppressing modulators and gRNA targeting the D4Z4 repetitive DNA array. The company reported suppression of DUX4 using their system in mice with humanized muscle tissue.

Epic Bio uses CasMINI, a modified form of Cas12f, licensed from Stanford for human use. The company’s pipeline includes treatments for FSHD, hypercholesterolemia, alpha-1 antitrypsin deficiency, retinitis pigmentosa 4 and autosomal dominant retinitis pigmentosa 11.

Facioscapulohumeral (FSH) Muscular Dystrophy is an epigenetic disease. Abnormal chromatin structure leads to aberrant activation of DUX4-FL, which is normally repressed, leads to disease pathology. Peter L. Jones and his team, now at University of Nevada used dCas9 fused to the KRAB repressor to silence DUX4-FL in muscle cell lines . A method of turning down gene expression by fusing dCas9 with DNA methyltransferase Dnmt3a, which adds methyl groups to target regions of DNA was described by Rudolph Jaenisch’s group .

Epic Bio used their GEMS platform to develop a potential treatment for FSHD, EPI-321 has a catalytically inactive Cas protein fused to gene-suppressing modulators and gRNA targeting the D4Z4 repetitive DNA array. The company reported suppression of DUX4 using their system in mice with humanized muscle tissue.

A method of turning down gene expression by fusing dCas9 with DNA methyltransferase Dnmt3a, which adds methyl groups to target regions of DNA was described by Rudolph Jaenisch’s group .

Facioscapulohumeral (FSH) Muscular Dystrophy is an epigenetic disease. Abnormal chromatin structure leads to aberrant activation of DUX4-FL, which is normally repressed, leads to disease pathology. Peter L. Jones and his team, now at University of Nevada used dCas9 fused to the KRAB repressor to silence DUX4-FL in muscle cell lines . A method of turning down gene expression by fusing dCas9 with DNA methyltransferase Dnmt3a, which adds methyl groups to target regions of DNA was described by Rudolph Jaenisch’s group .

Tune Therapeutics used epigenome editing in non-human primates, to decrease the expression levels of, PCSK9, a gene associated with cholesterol. The company used their CRISPR-based platform, TEMPO, to target PCSK9 and turn down gene expression and reported that LDL-cholesterol levels in the blood were decreased by 56 percent.

Epigenetic CRISPR-Cas9 epigenetic editing is a modified form of the genome editing platform CRISPR-Cas9 that does not cut DNA but affects gene expression levels. Gene expression levels depend on DNA methylation levels and whether chromatin conformation is in an active or repressed state. Epigenetic editing with CRISPR-Cas9 uses the nuclease dead Cas9 (dCas9) to target the genome and instead of altering the genetic sequence, the system alters the epigenome by bringing transcriptional activators, repressors and chromatin modifiers to the desired genomic region. This technique allows researchers to study how epigenetic marks like DNA methylation, histone acetylation and chromatin modifier proteins affect gene expression in cultured mammalian cells and live mice . Programmable gene regulation via Epigenetic CRISPR-Cas9 epigenetic editing has potential clinical applications .

Epigenetic CRISPR/Cas9 is a modified form of the gene editing technology CRISPR, designed to activate genes without cutting DNA by adding or removing methyl groups in specific positions.

Epigenetic CRISPR-Cas9 is a modified form of the genome editing platform CRISPR-Cas9 that does not cut DNA but affects gene expression levels. Gene expression levels depend on DNA methylation levels and whether chromatin conformation is in an active or repressed state. Epigenetic CRISPR-Cas9 uses the nuclease dead Cas9 (dCas9) to target the genome and instead of altering the genetic sequence, the system alters the epigenome by bringing transcriptional activators, repressors and chromatin modifiers to the desired genomic region. This technique allows researchers to study how epigenetic marks like DNA methylation, histone acetylation and chromatin modifier proteins affect gene expression in cultured mammalian cells and live mice . Programmable gene regulation via Epigenetic CRISPR-Cas9 has potential clinical applications .

This technique allows researchers to see how changes affect gene expression and has been tested in cultured mouse cells and live mice.

Juan Carlos Izpisua Belmonte of the Salk Institute for Biological Studies, California and his team designed guide RNAs to bring transcriptional activators with dCas9 to activate genes of interest . Instead of fixing the mutated gene in a disease, their approach is to upregulate other genes in the disease pathway that can compensate for the malfunctioning gene. In mouse models for kidney disease and muscular dystrophy their approach improved kidney and muscle function.

Acetylation modifications to histones, the proteins, which package DNA into chromatin change the conformation of the chromatin. Charles Gersbach and Timothy Reddy at Duke University, fused human acetyltransferase, p300 to dCas9. The fusion protein causes histone H3 lysine 27 to become acetylated at target sites, which activated target genes .

DNA methylation is a modification to DNA which regulates the expression of genes. Ronggui Hu’s lab at the Shanghai Institutes for Biological Sciences developed an epigenetic CRISPR-Cas9 system that includes the CpG demethylase enzyme, Tet1 to demethylate the promoter regions of target genes .

Hypermethylation and inactivity of the FMR1 gene is responsible for Fragile X Syndrome, the most common form of intellectual disability in males. Rudolph Jaenisch’s group at the Whitehead Institute for Biomedical Research, Cambridge, developed a version of dCas9-Tet1 which they used to activate FMR1 in induced pluripotent stem cells (iPSCs) from patients with Fragile X Syndrome . When the iPSCs with reactivated FMR1 were differentiated into neurons, neural function was rescued and remained rescued after transplant into mouse brain. Jaenisch’s group also showed that they could also use their system to activate FMR1 in post-mitotic neurons.

Facioscapulohumeral (FSH) Muscular Dystrophy is an epigenetic disease. Abnormal chromatin structure leads to aberrant activation of DUX4-FL, which is normally repressed, leads to disease pathology. Peter L. Jones and his team, now at University of Nevada used dCas9 fused to the KRAB repressor to silence DUX4-FL in muscle cell lines . A method of turning down gene expression by fusing dCas9 with DNA methyltransferase Dnmt3a, which adds methyl groups to target regions of DNA was described by Rudolph Jaenisch’s group .