Project description:RNA interference (RNAi) has considerable potential as a therapeutic strategy, but the development of efficient in vivo RNA delivery methods remains challenging. To this end, we designed and synthesized chemically modified interfering nanoparticles (iNOPs) composed of functionalized poly-l-lysine dendrimers modified with reducible spacers to facilitate release of small interfering RNAs (siRNAs) in vivo. We show that the novel siRNA-iNOP complexes mediate efficient gene-specific RNAi in cultured cells and in mice, where they display enhanced tissue-targeting capabilities. At a clinically feasible dose of 1 mg kg-1, apolipoprotein B (apoB) siRNA-iNOP complexes achieved ∼40-45% reduction of liver apoB mRNA and plasma apoB protein levels within 48 h of administration to mice, without apparent toxicity. Collectively, these findings demonstrate that siRNA delivery by the modified reducible iNOPs can provide a clinically significant and potentially tissue-specific new approach for RNAi therapy.
Project description:We investigated effects of the t haplotype in house mice, an autosomal male meiotic driver, on genome-wide gene expression patterns in males and females. We analysed gonads, liver and brain in adult sibling pairs differing in genotype, allowing us to identify t-associated differences in gene regulation. In testis, only 40% of differentially expressed genes mapped to the approximately 708 annotated genes comprising the t haplotype. Thus much of the activity of the t haplotype occurs in trans, and as up-regulation. Sperm maturation functions were enriched among both cis and trans acting t haplotype genes. Within the t haplotype, more down-regulation and differential exon usage was observed. In ovaries, liver, and brain, the majority of expression differences mapped to the t haplotype, and were largely independent of the differences seen in the testis. Overall, we found widespread transcriptional effects of this male meiotic driver in the house mouse genome.
Project description:The 9p21.3 cardiovascular disease locus is the most influential common genetic risk factor for coronary artery disease, accounting for ~10-15% of disease among non-African populations. The ~60kb risk haplotype is human-specific and lacks coding genes, hindering efforts to decipher its function. Genetic studies implicate the 9p21.3 locus and other risk genes to effects in the vascular wall. Here, we use genome editing to delete the entire risk on non-risk haplotype from the genomes of human iPSCs and perform genomewide transcriptional profiling along the timecourse of their differentiation into vascular smooth muscle cells (VSMCs). These studies identify a network of ~3000 genes governed by the risk haplotype in VSMCs that predict deficits in cell division, adhesion and contraction, which we confirmufunctionally. Remarkably, deleting the risk haplotype reverts VSMCs to resemble the non-risk VSMCs, suggesting that the risk region drives a cell state transition. transcriptionally and functionally. . Deleting the risk haplotype reverts these cells to reverted to the non-risk of iPSCs we show that the non-risk haplotype has little effect on locus we produce iPSCs from risk and non-risk individuals, delete each haplotype using genome editing and generate vascular smooth muscle cells (VSMCs). We show that risk VSMCs exhibit aberrant adhesion and contraction, concomitant with dramatically altered global transcriptional changes that are enriched in previously identified cardiovascular disease genes and pathways. Unexpectedly, deleting the risk haplotype rescues VSMC transcriptional identity and function, while expressing the 9p21.3-associated long non-coding RNA ANRIL induces risk phenotypes in non-risk VSMCs. This studies shows that the risk haplotype dominantly predisposes VSMCs to adopt perturbed phenotypes associated with cardiovascular disease and establishes haplotype-edited iPSCs as powerful tools for functionally annotating human-specific variation in non-coding genomic regions.
Project description:Constructing high-quality haplotype-resolved genome assemblies has substantially improved the ability to detect and characterize genetic variants. A targeted approach providing readily access to the rich information from haplotype-resolved genome assemblies will be appealing to groups of basic researchers and medical scientists focused on specific genomic regions. Here, using the 4.5 megabase, notoriously difficult-to-assemble major histocompatibility complex (MHC) region as an example, we demonstrated an approach to construct haplotype-resolved assembly of the targeted genomic region with the CRISPR-based enrichment. Compared to the results from haplotype-resolved genome assembly, our targeted approach achieved comparable completeness and accuracy with reduced computing complexity, sequencing cost, as well as the amount of starting materials. Moreover, using the targeted assembled personal MHC haplotypes as the reference both improves the quantification accuracy for sequencing data and enables allele-specific functional genomics analyses of the MHC region. Given its highly efficient use of resources, our approach can greatly facilitate population genetic studies of targeted regions, and may pave a new way to elucidate the molecular mechanisms in disease etiology.