CRISPR-Cas9 delivery by AAV holds promise for gene therapy but faces critical barriers due to its potential immunogenicity and limited payload capacity. Here, we demonstrate genome engineering in postnatal mice using AAV-split-Cas9, a multi-functional platform customizable for genome-editing, transcriptional regulation, and other previously impracticable AAV-CRISPR-Cas9 applications. We identify crucial parameters that impact efficacy and clinical translation of our platform, including viral biodistribution, editing efficiencies in various organs, antigenicity, immunological reactions, and physiological outcomes. These results reveal that AAV-CRISPR-Cas9 evokes host responses with distinct cellular and molecular signatures, but unlike alternative delivery methods, does not induce detectable cellular damage in vivo. Our study provides a foundation for developing effective genome therapeutics Overall design: mRNA-Seq from muscles (9 samples; 3 mice x 3 conditions) and lymph nodes (9 samples; 3 mice x 3 conditions).
A multifunctional AAV-CRISPR-Cas9 and its host response.
Specimen part, Cell line, Subject
View SamplesLoss of immune function and an increased incidence of myeloid leukemia are two of the most clinically significant consequences of aging of the hematopoietic system. To better understand the mechanisms underlying hematopoietic aging, we evaluated the cell intrinsic functional and molecular properties of highly purified long-term hematopoietic stem cells (LT-HSCs) from young and old mice. We found that LT-HSC aging was accompanied by cell autonomous changes, including increased stem cell self-renewal, differential capacity to generate committed myeloid and lymphoid progenitors, and diminished lymphoid potential. Expression profiling revealed that LT-HSC aging was accompanied by the systemic down-regulation of genes mediating lymphoid specification and function and up-regulation of genes involved in specifying myeloid fate and function. Moreover, LT-HSCs from old mice expressed elevated levels of many genes involved in leukemic transformation. These data support a model in which age-dependent alterations in gene expression at the stem cell level presage downstream developmental potential and thereby contribute to age-dependent immune decline, and perhaps also to the increased incidence of leukemia in the elderly.
Cell intrinsic alterations underlie hematopoietic stem cell aging.
No sample metadata fields
View SamplesWe report age-related gene expression of Treg cells isolated from injured muscle and spleen. Male C57BL/6 Foxp3-GFP reporter mice were injured intramuscularly with cardiotoxin. Tregs were sorted directly into Trizol from injured muscle and spleen 4 days post-injury. Overall design: Gene expression profiling of muscle and splenic Tregs from 2- vs >6-month old mice (biological duplicate for each).
Poor Repair of Skeletal Muscle in Aging Mice Reflects a Defect in Local, Interleukin-33-Dependent Accumulation of Regulatory T Cells.
Sex, Age, Subject
View SamplesIt has been known for some time that muscle repair potential becomes increasingly compromised with advancing age, and that this age-related defect is associated with reduced activity of muscle satellite cells and with the presence of chronic, low grade inflammation in the muscle. Working from the hypothesis that a heightened inflammatory tone in aged muscle could contribute to poor regenerative capacity, we developed genetic systems to inducibly alter inflammatory gene expression in satellite cells or muscle fibers by modulation of the activity of nuclear factor B (NF-B), a master transcriptional regulator of inflammation whose activity is upregulated in many cell types and tissues with age. These studies revealed that activation of NF-B activity in muscle fibers, but not in satellite cells, drives muscle dysfunction and that lifelong inhibition of NF-B activity in myofibers preserves muscle regenerative potential with aging via cell-non-autonomous effects on satellite cell function. Further analysis of differential gene expression in muscles with varying NF-B activity identified a secreted phospholipase (PLA2G5) as a myofiber-expressed NF-B-regulated gene that governs muscle regenerative capacity with age. Together, these data suggest a model in which NF-B activation in muscle fibers increases PLA2G5 expression and drives the impairment in regenerative function characteristic of aged muscle. Importantly, inhibition of NF-B function reverses this impairment, suggesting that FDA-approved drugs, like salsalate, a prodrug form of sodium salicylate, may provide new therapeutic avenues for elderly patients with reduced capacity to recover effectively from muscle injury.
Age-associated NF-κB signaling in myofibers alters the satellite cell niche and re-strains muscle stem cell function.
Age
View SamplesWe report gene expression of Treg cells isolated from injured muscle in IL-33 vs PBS treated mice. Male Foxp3-GFP C57BL/6 reporter (2 months old) mice were injured intramuscularly with cardiotoxin/rIL-33 (0.3 ug/muscle). Tregs were sorted directly into Trizol from injured muscle 4 days post-injury. Overall design: Gene expression profiling of muscle Tregs from IL-33 vs PBS injured mice.
Poor Repair of Skeletal Muscle in Aging Mice Reflects a Defect in Local, Interleukin-33-Dependent Accumulation of Regulatory T Cells.
Sex, Age, Treatment, Subject
View SamplesThis work examines sarcoma formation within discrete subsets of KRAS(G12V)-expressing p16p19null myogenic and mesenchymal cells found normally in skeletal muscle. We show that prospectively isolated skeletal muscle precursor cells (SMPs) within the satellite cell pool can serve as cancer cells-of-origin for mouse rhabdomyosarcomas (soft tissue sarcomas with features of myogenic differentiation). Alternatively, non-myogenic progenitors (ScaPCs) induce sarcomas lacking myogenic differentiation markers.
Sarcomas induced in discrete subsets of prospectively isolated skeletal muscle cells.
Specimen part
View SamplesNovel fluorescence-activated cell sorting (FACS) strategies to prospectively purify functionally distinct cell populations from the human myofiber-associated (hMFA) cell compartment, including human Skeletal Muscle Precursor cells (hSMPs):
Isolation of progenitors that exhibit myogenic/osteogenic bipotency in vitro by fluorescence-activated cell sorting from human fetal muscle.
No sample metadata fields
View SamplesMultipotent stromal cells (MSC) and their osteoblastic lineage cell (OBC) derivatives are part of the bone marrow (BM) niche and contribute to hematopoietic stem cell (HSC) maintenance. During myeloproliferative neoplasm (MPN) development, MSCs are stimulated to overproduce functtionally altered OBCs, which accumulate in the BM cavity as myelofibrotic cells. These MPN-expanded OBCs, in turn, impair the maintenance of normal HSCs but not of leukemic stem cells.
Myeloproliferative neoplasia remodels the endosteal bone marrow niche into a self-reinforcing leukemic niche.
Specimen part, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A special population of regulatory T cells potentiates muscle repair.
Sex, Age, Specimen part, Treatment, Time
View SamplesA phenotypically and functionally distinct population of CD4+ Foxp3+ T cells (Tregs) rapidly accumulates in acutely injured skeletal muscle of mice, just as invading myeloid-lineage cells switch from a pro-inflammatory to a pro-regenerative state. Analysis of gene expression of Tregs and CD4+Foxp3- T cells (Tconvs) from injured muscle and spleen revealed that the transcriptome of muscle Treg cells is distinct from that of splenic Tregs. A set of genes is uniquely expressed by muscle Tregs, while another set is over-expressed by the two muscle populations vis--vis their two spleen counterparts.
A special population of regulatory T cells potentiates muscle repair.
Sex, Age, Specimen part, Treatment, Time
View Samples