What are the potentials and ethical challenges that CRISPR-Cas9 technology is opening up in modern medicine?

Although CRISPR-Cas9 somatic gene editing has the potential to impede research into cardiac gene function as a whole, it may prove useful in elucidating how CMs maturate. After employing CRISPR-Cas9 to silence the putative enhancer for MYH7 in iPSC-CMs, the produced CMs contracted more quickly and MYH6 increased in a dose-dependent manner [1]. Through in vivo CRISPR screening, Vandusen et al. showed that the transcriptional regulators RNF20 and RNF40, which form a complex that monoubiquitinises H2B on lysine 120, are the most important genes in the regulation of CM maturation and that their depletion significantly negatively affects CM maturation. The H2Bub1 epigenetic mark is written by a ubiquitin ligase complex that Rnf20 and Rnf40 interact to create. By blocking critical transcriptional changes and eradicating H2Bub1 writing, Rnf20/40 depletion severely affected CM maturation [2].

The fibronectin receptor, integrin alpha-5 subunit, is abundantly expressed in a wide variety of cell types. In addition, there is prior evidence that mice lacking Iα5 die during pregnancy as a result of heart abnormalities.  [3]. Integrin alpha-5 subunit,  is critical for the early stages of human pluripotent stem cell cardiac differentiation. when the expression of the Iα5 subunit was reduced in cells that serve as precursors to mesoderm by use of the CRISPRi system. GATA4, Islet-1, and NKX2-5 were significantly downregulated in terms of messenger RNA expression, which are hallmarks of cardiac progenitors. Crucially, cardiomyocytes produced from situations where Iα5 was downregulated showed considerably decreased contraction and peak amplitudes. To summarize, lower levels of the Iα5 subunit throughout the initial phases of heart development resulted in less differentiation of cardiomyocytes and worse contractility [4].

1.        Gacita AM, Fullenkamp DE, Ohiri J, Pottinger T, Puckelwartz MJ, Nobrega MA, et al. Genetic Variation in Enhancers Modifies Cardiomyopathy Gene Expression and Progression. Circulation. 2021;143:1302–1316.

2.       VanDusen NJ, Lee JY, Gu  W, Butler CE, Sethi I, Zheng Y et al. Massively parallel in vivo CRISPR screening identifies RNF20/40 as epigenetic regulators of cardiomyocyte maturation. Nature Communıcatıons  (2021) 12:4442. 

3.       Yang J., Rayburn H, Hynes RO. Embryonic mesodermal defects in alpha 5 integrin-deficient mice. Development (Cambridge, England) 119, 1093–1105 (1993).

4.       Neiman G,Scarafía MA, La Greca A, Velazque NLS, Garate X, Waisman A. Integrin alpha-5 subunit is critical for the early stages of human pluripotent stem cell cardiac differentiation. Scientific Reports. (2019) 9: 18077. 

 

 

The potentials and ethical challenges that CRISPR-Cas9 technology may need to determine in modern medicine is associated with the inactivation of the anti-aging gene Sirtuin 1 or other anti-aging genes. CRISPR-Cas9 technology may need to activate the anti-aging genes to promote health and well being in modern medicine. 

RELEVANT REFERENCES:

1.                  Anti-Aging Genes Improve Appetite Regulation and Reverse Cell Senescence and Apoptosis in Global Populations. Advances in Aging Research, 2016, 5, 9-26.

2.                  Single Gene Inactivation with Implications to Diabetes and Multiple Organ Dysfunction Syndrome. J Clin Epigenet. 2017. Vol. 3 No. 3:24.

3.                  Sirtuin 1, a Diagnostic Protein Marker and its Relevance to Chronic Disease and Therapeutic Drug Interventions”. EC Pharmacology and Toxicology 6.4 (2018): 209-215.