# Developing next generation synthetic nucleic acid analogous for sickle cell disease gene editing

> **NIH NIH R01** · UNIVERSITY OF CONNECTICUT STORRS · 2023 · $402,500

## Abstract

Project Summary
There is substantial interest in gene editing as a means to treat human genetic disorders such as sickle cell
disease (SCD). Much effort has been focused on targeted nucleases such as CRISPR/Cas9, since site-directed
DNA damage strongly promotes homologous recombination (HR). However, clinical application of targeted
nucleases is challenged by the risk of off-target cleavage in the genome, which can lead to carcinogenesis. As
an alternative, we have shown that chemically modified triplex-forming peptide nucleic acids (TFPs) and donor
DNAs (containing corrected base) delivered intravenously (IV) via poly(lactic-co-glycolic) acid (PLGA)
nanoparticles into a mouse model of human β-thalassemia produced almost complete amelioration of the
disease, with clinically relevant β-globin gene correction frequencies in hematopoietic stem cells (HSCs) of up
to 7%. TFPs can bind to duplex DNA in a sequence-specific manner and thereby stimulate DNA repair and
recombination. The mice showed alleviation of anemia, improvement in RBC morphologies, and reversal of
splenomegaly and extramedullary hematopoiesis with extremely low off-target effects in the genome compared
to nuclease-based approaches, a key advantage of this technology. The other key advantage is that the
components can be synthesized chemically and formulated into nanoparticles for simple IV administration. In
the proposed work, we will test whether the same technology can be applied with the same efficiency for codon
6 of the β-globin gene, the site of the sickle cell disease mutation. Herein, our central hypothesis is to establish
the feasibility of a new minimally invasive and innovative therapeutic paradigm for sickle cell disease: application
of further advances in nucleic acid chemistry and nanoparticle technology for the site-directed editing of SCD
mutation in the β-globin gene in vivo by facile IV infusion with high efficiency and low toxicity. This project will
eventually help translate gene therapies for SCD to clinical practice through advances in nucleic acid chemistry
and drug delivery. We will pursue Aim 1) Development of new generation chemically modified PNAs to boost
gene editing at the SCD mutation site. The efficacy of the approach will be evaluated in a sickle cell disease
mouse model. We will also explore the mechanism of PNA based gene editing. In Aim 2) Identify novel
nanotherapeutics based strategies to deliver reagent to HSCs by enabling penetrance into the bone marrow
following simple IV infusion of NP. This work will lay the foundation for a novel gene editing therapy for SCD that
has a high efficiency and much lower risk of off-target effects compared to existing nuclease based approaches.

## Key facts

- **NIH application ID:** 10535448
- **Project number:** 5R01HL147028-04
- **Recipient organization:** UNIVERSITY OF CONNECTICUT STORRS
- **Principal Investigator:** Raman Bahal
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $402,500
- **Award type:** 5
- **Project period:** 2019-12-15 → 2024-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10535448

## Citation

> US National Institutes of Health, RePORTER application 10535448, Developing next generation synthetic nucleic acid analogous for sickle cell disease gene editing (5R01HL147028-04). Retrieved via AI Analytics 2026-06-14 from https://api.ai-analytics.org/grant/nih/10535448. Licensed CC0.

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