CRISPR/Cas9- A viable alternative in the treatment of Cystic Fibrosis - A review Anithashree.S, Saraswati.S Department Of Biotechnology. Maharani Lakshmi Ammanni College For Women Autonomous, Bangalore. INTRODUCTION •
Cystic fibrosis (CF) is a rare autosomal recessive disorder which affects the pulmonary and digestive system.
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CFT R gene encodes an anionic ATP bound channel which maintains the homeostasis of fluids and electrolytes in apical membrane of exocrine epithelial cells.
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Mutation in this gene lead to accumulation of thick viscous mucus in the pulmonary and gastrointestinal ducts. T he inhibition of ciliary function in the lungs leads to severe pneumonia and bronchitis, which reduces the life expectancy to 40. (Jeffrey et.al., 2017)
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Mutations are classified into 6 types , the common one being a deletion ) in exon 11 (CFTR F508del) which leads to misfolding in CFT R thus impairing exocytic trafficking and is retained in endoplasmic reticulum causing its early degradation.
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Incidence among Caucasians is reported to be 1 in 2500-3000. T he incidence among migrant Indian populations in U.S.A and U.K was lower , from 1:10,000 to 1:40,000. The frequency of common mutation F508del among Indian children was between 19% and 34%. (Kabra et.al.,2007)
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T he different methods of treatment employed that are FDA approved are CFTR modulators( Potentiators, correctors, amplifiers, stabilisers), gene therapy (viral vectors, non viral vectors, Adeno-Associated vectors )
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Other methods of treatment that are still in clinical trial level are Stem cell therapy, CRISPR-mediated genome editing, read through therapies and NMD inhibitors, mRNA mediated Therapy, Antisenseoligonucleotide-mediated(Pranke et.al., 2019)
(Pranke et.al.,2019)
OUR PERSPECTIVE (Marangi M et.al.,2018)
(Hodge et.al.,2018) •
Why CRISPR Cas9 method? T hree important components of CRISPR are guide RNA, Cas9 nuclease, repair template.
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CRISPR is introduced into the cell through non viral vectors, aerosol delivery devices which have nanoparticles, lipofectamine mediated transfection (target :intestinal cells) (Pranke et.al., 2019)
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Once introduced into the cell CRISPR recognises the DNA with mutation using a PAM sequence.
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Cas9 binds with gRNA and gets activated; it, in turn, binds to the DNA, later cleaves and replaces the region using template. The DNA is then corrected either using HDR or NHEJ repair system, and the expressed CFT R protein starts functioning properly.
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T his bacterial derived RNA guided endonuclease is cost effective and could potentially serve as a viable alternative in treatment of CF.
ACKNOWLEDGEMENT •
My sincere thanks to Dr S.Saraswati, Department of Biotechnology Maharani Lakshmi Ammanni College for Women Autonomous Bangalore for her invaluable guidance in writing this review.
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I would also thank Dr Babitha HOD, Biotechnology, Dr.Jolitha A.B., Coordinator, PG Biotechnology and Dr Sushma Bavle, Principal Maharani Lakshmi Ammanni College for Women Autonomous for the ir continuous support.