1
|
Nitzahn M, Truong B, Khoja S, Vega-Crespo A, Le C, Eliav A, Makris G, Pyle AD, Häberle J, Lipshutz GS. CRISPR-Mediated Genomic Addition to CPS1 Deficient iPSCs is Insufficient to Restore Nitrogen Homeostasis. Yale J Biol Med 2021; 94:545-557. [PMID: 34970092 PMCID: PMC8686786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CPS1 deficiency is an inborn error of metabolism caused by loss-of-function mutations in the CPS1 gene, catalyzing the initial reaction of the urea cycle. Deficiency typically leads to toxic levels of plasma ammonia, cerebral edema, coma, and death, with the only curative treatment being liver transplantation; due to limited donor availability and the invasiveness and complications of the procedure, however, alternative therapies are needed. Induced pluripotent stem cells offer an alternative cell source to partial or whole liver grafts that theoretically would not require immune suppression regimens and additionally are amenable to genetic modifications. Here, we genetically modified CPS1 deficient patient-derived stem cells to constitutively express human codon optimized CPS1 from the AAVS1 safe harbor site. While edited stem cells efficiently differentiated to hepatocyte-like cells, they failed to metabolize ammonia more efficiently than their unedited counterparts. This unexpected result appears to have arisen in part due to transgene promoter methylation, and thus transcriptional silencing, in undifferentiated cells, impacting their capacity to restore the complete urea cycle function upon differentiation. As pluripotent stem cell strategies are being expanded widely for potential cell therapies, these results highlight the need for strict quality control and functional analysis to ensure the integrity of cell products.
Collapse
Affiliation(s)
- Matthew Nitzahn
- Molecular Biology Institute, David Geffen School of
Medicine at UCLA, Los Angeles, CA, USA,Department of Surgery, David Geffen School of Medicine
at UCLA, Los Angeles, CA, USA
| | - Brian Truong
- Department of Surgery, David Geffen School of Medicine
at UCLA, Los Angeles, CA, USA,Department of Molecular and Medical Pharmacology, David
Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Suhail Khoja
- Department of Surgery, David Geffen School of Medicine
at UCLA, Los Angeles, CA, USA
| | - Agustin Vega-Crespo
- Department of Molecular and Medical Pharmacology, David
Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Colleen Le
- Department of Surgery, David Geffen School of Medicine
at UCLA, Los Angeles, CA, USA
| | - Adam Eliav
- Department of Surgery, David Geffen School of Medicine
at UCLA, Los Angeles, CA, USA
| | - Georgios Makris
- Division of Metabolism and Children’s Research Center,
University Children’s Hospital Zurich, Switzerland
| | - April D. Pyle
- Department of Microbiology, Immunology, and Molecular
Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA,Eli and Edythe Broad Stem Cell Center, David Geffen
School of Medicine at UCLA, Los Angeles, CA, USA
| | - Johannes Häberle
- Division of Metabolism and Children’s Research Center,
University Children’s Hospital Zurich, Switzerland
| | - Gerald S. Lipshutz
- Molecular Biology Institute, David Geffen School of
Medicine at UCLA, Los Angeles, CA, USA,Department of Surgery, David Geffen School of Medicine
at UCLA, Los Angeles, CA, USA,Department of Molecular and Medical Pharmacology, David
Geffen School of Medicine at UCLA, Los Angeles, CA, USA,Department of Psychiatry, David Geffen School of
Medicine at UCLA, Los Angeles, CA, USA,Intellectual and Developmental Disabilities Research
Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA,Semel Institute for Neuroscience, David Geffen School
of Medicine at UCLA, Los Angeles, CA, USA,To whom all correspondence should be addressed:
Gerald S. Lipshutz, David Geffen School of Medicine at UCLA, Los Angeles, CA
90095-7054;
| |
Collapse
|