# Vascular networks genetically engineered for protein drug delivery

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2021 · $662,263

## Abstract

PROJECT SUMMARY/ABSTRACT
Hemophilia A is an inherited bleeding disorder caused by mutations in the F8 gene encoding coagulation factor
VIII (FVIII). Current treatment involves repeated i.v. infusions of FVIII concentrates throughout the life of the
patient, which creates tremendous discomfort and morbidity. Alternatively, we seek to develop a novel
technology for sustained FVIII delivery. Recently, we developed a non-viral ex vivo gene therapy approach for
hemophilia A. We used a piggyBac DNA transposon system to insert 70 copies of the F8 gene into human
pluripotent stem cells (PSCs). We differentiated these modified F8-PSCs into endothelial cells (iECs; natural
producers of FVIII) and demonstrated the production of exceedingly high levels of FVIII. After subcutaneous
engraftment of our human F8-iECs into immunodeficient hemophilic (SCID-f8ko) mice, we achieved up to 600%
circulating levels of FVIII, effectively correcting the clotting deficiency. Notwithstanding this progress, our open-
graft approach has some inherent limitations for translation: 1) immune rejection of non-autologous cells, and 2)
concerns over cell dissemination and safety. To address these limitations, we have teamed up with Dr. Minglin
Ma (Cornell), who has extensive experience with devices for encapsulation and transplantation of cells in mice
and dogs. We propose a technology entailing a novel retrievable encapsulation device. We will assemble our
F8-iECs into stable 3D vascular organoids and will then embed multiple organoids into an alginate hydrogel
inside a tubular encapsulation device (1-mm diameter; variable length). Based on our preliminary data,
we hypothesize that our device will protect the cells from immune rejection and produce FVIII that will reach the
bloodstream at therapeutic levels upon implantation into the peritoneal cavity. To test these hypotheses, we
propose three Specific Aims. In Aim-1, we will genetically engineer vascular organoids for the production of
clinically relevant levels of FVIII. We will develop a new promoterless exon-trap sensor cassette to avoid intra-
exon integration of our piggyBac transposon. We will then insert multiple F8 copies into NIH-eligible PSC lines
to generate universal clones for high FVIII production. In Aim-2, we will establish an encapsulation device
configuration for optimal FVIII production and determine the safety and long-term efficacy in immunocompetent
hemophilic mice. We will evaluate cell survival, BDD-FVIII activity in plasma, correction of coagulation deficiency,
risk of teratoma formation, and reversibility of the treatment. In Aim-3, we will evaluate the safety and long-term
efficacy of our devices in dogs. We will first generate canine-specific FVIII-secreting vascular organoids. We will
then transplant our devices (I.P.) in healthy dogs for up to 6 months and evaluate scalability, safety, retrievability,
and FVIII production. Lastly, we will test our allogeneic devices in hemophilia A dogs and establis...

## Key facts

- **NIH application ID:** 10297294
- **Project number:** 2R01HL128452-06A1
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** Minglin Ma
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $662,263
- **Award type:** 2
- **Project period:** 2015-08-15 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10297294

## Citation

> US National Institutes of Health, RePORTER application 10297294, Vascular networks genetically engineered for protein drug delivery (2R01HL128452-06A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10297294. Licensed CC0.

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