ABSTRACT
Monogenic blood diseases are among the most common genetic disorders worldwide. These diseases result in significant pediatric and adult morbidity, and some can result in death prior to birth. Novel ex vivo hematopoietic stem cell (HSC) gene editing therapies hold tremendous promise to alter the therapeutic landscape but are not without potential limitations. In vivo gene editing therapies offer a potentially safer and more accessible treatment for these diseases but are hindered by a lack of delivery vectors targeting HSCs, which reside in the difficult-to-access bone marrow niche. Here, we propose that this biological barrier can be overcome by taking advantage of HSC residence in the easily accessible liver during fetal development. To facilitate the delivery of gene editing cargo to fetal HSCs, we developed an ionizable lipid nanoparticle (LNP) platform targeting the CD45 receptor on the surface of HSCs. After validating that targeted LNPs improved messenger ribonucleic acid (mRNA) delivery to hematopoietic lineage cells via a CD45-specific mechanism in vitro, we demonstrated that this platform mediated safe, potent, and long-term gene modulation of HSCs in vivo in multiple mouse models. We further optimized this LNP platform in vitro to encapsulate and deliver CRISPR-based nucleic acid cargos. Finally, we showed that optimized and targeted LNPs enhanced gene editing at a proof-of-concept locus in fetal HSCs after a single in utero intravenous injection. By targeting HSCs in vivo during fetal development, our Systematically optimized Targeted Editing Machinery (STEM) LNPs may provide a translatable strategy to treat monogenic blood diseases before birth.
Subject(s)
Gene Editing , Hematopoietic Stem Cells , Nanoparticles , Animals , Hematopoietic Stem Cells/metabolism , Gene Editing/methods , Nanoparticles/chemistry , Mice , Female , Pregnancy , Lipids/chemistry , Leukocyte Common Antigens/metabolism , Leukocyte Common Antigens/genetics , Humans , Genetic Therapy/methods , CRISPR-Cas Systems , LiposomesABSTRACT
Delivery of mRNA-based therapeutics to the perinatal brain holds great potential in treating congenital brain diseases. However, nonviral delivery platforms that facilitate nucleic acid delivery in this environment have yet to be rigorously studied. Here, we screen a diverse library of ionizable lipid nanoparticles (LNPs) via intracerebroventricular (ICV) injection in both fetal and neonatal mice and identify an LNP formulation with greater functional mRNA delivery in the perinatal brain than an FDA-approved industry standard LNP. Following in vitro optimization of the top-performing LNP (C3 LNP) for codelivery of an adenine base editing platform, we improve the biochemical phenotype of a lysosomal storage disease in the neonatal mouse brain, exhibit proof-of-principle mRNA brain transfection in vivo in a fetal nonhuman primate model, and demonstrate the translational potential of C3 LNPs ex vivo in human patient-derived brain tissues. These LNPs may provide a clinically translatable platform for in utero and postnatal mRNA therapies including gene editing in the brain.
Subject(s)
Brain Diseases , Nanoparticles , Mice , Humans , Animals , Gene Editing , Lipids , Liposomes , RNA, Messenger/genetics , RNA, Small Interfering/geneticsABSTRACT
In utero hematopoietic cell transplantation (IUHCT) is an experimental treatment for congenital hemoglobinopathies, including Sickle cell disease and thalassemias. One of the principal advantages of IUHCT is the predisposition of the developing fetus toward immunologic tolerance. This allows for engraftment across immune barriers without immunosuppression and, potentially, decreased susceptibility to graft-versus-host disease (GVHD). We demonstrate fetal resistance to GVHD following T cell-replete allogeneic hematopoietic cell transplantation compared with the neonate. We show that this resistance is associated with elevated fetal serum interleukin-10 conducive to the induction of regulatory T cells (Tregs). Finally, we demonstrate that the adoptive transfer of Tregs from IUHCT recipients to neonates uniformly prevents GVHD, recapitulating the predisposition to tolerance observed after fetal allotransplantation. These findings demonstrate fetal resistance to GVHD following hematopoietic cell transplantation and elucidate Tregs as important contributors.
Subject(s)
Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Humans , Infant, Newborn , Graft vs Host Disease/etiology , Graft vs Host Disease/prevention & control , Hematopoietic Stem Cell Transplantation/adverse effects , Immune Tolerance , Fetus , T-Lymphocytes, RegulatoryABSTRACT
BACKGROUND: Enteral nutrition is a critical intervention that supports the growth of children with pulmonary hypoplasia (PH). We explored the experiences of caregivers and providers caring for children with PH to better understand gaps in knowledge transfer and identify barriers and facilitators to caregiving to inform interventions that may improve support. METHODS: This qualitative study included 10 interviews with caregivers and 10 clinical team members at a single integrated care program for children with PH. An inductive and iterative coding strategy was employed to produce a codebook. After cluster analysis, themes were generated to capture participant sentiments. RESULTS: Themes were defined along a care continuum (1) initiation, (2) adaptation, and (3) maintenance that represented distinct phases of adjustment to enteral nutrition support (1) in the perinatal period and initial neonatal intensive care unit (NICU) admission, (2) from discharge planning through the family's first days at home and establishment of a stable feeding regime, and (3) through long-term follow-up and weaning. Notable subthemes included uncertainty, partnerships in training, and obstacles to adaptation. CONCLUSIONS: Among children with PH, the caregiver-provider relationship during the perinatal and NICU course is critical to promoting caregiver adaptation to the needs of the child. Ongoing considerations to support resource alignment and transition to a stable feeding regimen may facilitate caregiver adjustment to a "new normal," culminating in successful growth and/or weaning. These findings will inform interventions focused on training curricula, discharge planning, and the provision of follow-up in the context of an integrated care program for PH.
Subject(s)
Caregivers , Enteral Nutrition , Caregivers/education , Child , Family , Humans , Infant , Infant, Newborn , Intensive Care Units, Neonatal , Qualitative ResearchABSTRACT
Animals with elodont dentition and unfused mandible symphyses are hypothesized to have symmetric incisor morphology. Since these animals maintain their teeth by gnawing, they may provide physiologic feedback on mechanical function when unilateral mandible defects are created that manifest as ipsilateral changes in tooth structure. This defect model would potentially generate important information on the functional/mechanical properties of implants. Rats' and rabbits' mandibles and teeth are analyzed with µCT at baseline and post-intervention (n = 8 for each). Baseline incisors were compared. In a unilateral mandible pilot study, defects-ranging from critical size defect to complete ramus osteotomies-were created to assess effect on dentition (rats, n = 7; rabbits, n = 6). Within 90% confidence intervals, animals showed no baseline left/right differences in their incisors. There are apparent dental changes associated with unilateral defect type and location. Thus, at baseline, animals exhibit statistically significant incisor symmetry and there is an apparent relationship between mandible defect and incisor growth. The baseline symmetry proven here sets the stage to study the degree to which hemi-mandible destabilizing procedures result in measurable & reproducible disruption of dental asymmetry. In a validated model, an implant designed to function under load that prevents incisor asymmetry would provide supporting evidence that the implant has clinically useful load-bearing function.
ABSTRACT
In utero base editing has the potential to correct disease-causing mutations before the onset of pathology. Mucopolysaccharidosis type I (MPS-IH, Hurler syndrome) is a lysosomal storage disease (LSD) affecting multiple organs, often leading to early postnatal cardiopulmonary demise. We assessed in utero adeno-associated virus serotype 9 (AAV9) delivery of an adenine base editor (ABE) targeting the Idua GâA (W392X) mutation in the MPS-IH mouse, corresponding to the common IDUA GâA (W402X) mutation in MPS-IH patients. Here we show efficient long-term W392X correction in hepatocytes and cardiomyocytes and low-level editing in the brain. In utero editing was associated with improved survival and amelioration of metabolic, musculoskeletal, and cardiac disease. This proof-of-concept study demonstrates the possibility of efficiently performing therapeutic base editing in multiple organs before birth via a clinically relevant delivery mechanism, highlighting the potential of this approach for MPS-IH and other genetic diseases.