Project description:Despite advances in nuclease-based genome editing technologies, correcting human disease-causing genomic inversions remains a challenge. Here, we describe the potential use of a recombinase-based system to correct a 140 kb int1h inversion frequently found in patients diagnosed with Hemophilia A. With the use of directed molecular evolution, we developed a linked heterodimeric recombinase system (RecF8) achieving 30% inversion of the target sequence in human tissue culture cells. Transient RecF8 treatment of endothelial cells, differentiated from int1h patient derived iPSCs, resulted in prominent correction of the inversion and restored Factor VIII mRNA expression. Our data suggest that the development of designer-recombinases represent an efficient and specific mean towards treatment of large gene inversions causing monogenic diseases.
Project description:Despite advances in nuclease-based genome editing technologies, correcting human disease-causing genomic inversions remains a challenge. Here, we describe the potential use of a recombinase-based system to correct the 140 kb inversion of the F8 gene frequently found in patients diagnosed with severe Hemophilia A. Employing substrate-linked directed molecular evolution, we developed a coupled heterodimeric recombinase system (RecF8) achieving 30% inversion of the target sequence in human tissue culture cells. Transient RecF8 treatment of endothelial cells, differentiated from patient derived induced pluripotent stem cells (iPSCs) of a hemophilic donor, resulted in 12% correction of the inversion and restored Factor VIII mRNA expression. Our data suggests that designer-recombinases may represent efficient and specific means towards treatment of monogenic diseases caused by large gene inversions.
Project description:Confirmation of the nuclease acivities at the On- and Off-target sites; Hemophilia A (HA) is caused by genetic mutations in the blood coagulation factor VIII (FVIII). Genome editing approaches can be used to target the mutated site itself in patient-derived induced pluripotent stem cells (iPSCs). However, these approaches can be hampered by difficulty preparing thousands of editing platforms for each corresponding variant found in HA patients. Here, we report a universal approach to correct the various mutations in HA patient iPSCs by the targeted insertion of the FVIII gene into the human H11 site via CRISPR/Cas9. We derived corrected clones from two types of patient iPSCs with frequencies of up to 64% and 66%, respectively, without detectable unwanted off-target mutations. Moreover, we demonstrated that endothelial cells differentiated from the corrected iPSCs successfully secreted functional protein in vitro and functionally rescued the disease phenotype in vivo. This strategy may provide a universal therapeutic method for correcting all genetic variants found in HA patients.
Project description:The piperazine derivatives most frequently consumed for recreational purposes are 1-benzylpiperazine (BZP), 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP), and 1-(4-methoxyphenyl)piperazine (MeOPP). Currently it is unclear whether piperazine designer drugs induce mechanisms of hepatotoxicity and, if so, whether they act by a common mechanism. We performed a gene array study with rat hepatocytes incubated with the four designer drugs for 24 h in order to detail the global programme of gene expression Primary rat hepatocytes were cultured in collagen sandwich and incubated with the piperazine designer drugs. After 24 h, the RNA was extracted and the Affymetrix microarray analysis was performed.
Project description:To investigate the gene expression in dendritic cells after treating hemiphilic mice with HBSS, plasma derived or recombinant factor VIII Gene expression in dendritic cells were measured 24 hours post treatment
Project description:von Willebrand factor (VWF) is the protective carrier of procoagulant factor VIII (FVIII) in the shear forces of the circulation, prolonging its half‐life and delivering it to the developing thrombus. VWF∙FVIII complex formation is characterized by catch‐bond behavior in which force first decelerates then accelerates bond dissociation. Patients with mutations in VWF at the FVIII binding site phenocopies hemophilia A and the most common mutations involve cysteine residues of multiple disulfides. Thirteen VWF disulfide bonds at the FVIII binding site exist in formed and unformed states, and binding of FVIII results in partial formation of 12 of the VWF bonds. The VWF∙FVIII bond stiffens in response to force and this property is ablated when VWF disulfide bonds are prevented from forming, resulting in slip‐bond behavior. These findings demonstrate that FVIII binding to VWF involves dynamic changes in the covalent states of several VWF disulfides that are required for productive interaction.
Project description:To investigate the gene expression in dendritic cells after treating hemiphilic mice with HBSS, plasma derived or recombinant factor VIII Gene expression in dendritic cells were measured 24 hours post treatment Hemophilic mice with treated with either (HBSS, rFVIII or pdFVIII) 24 hours post treatment the spleens were isolated and CD11+ DCs were purified. The gene expression in the DCs were then investigated by microarray studies.