Dual CRISPR-Cas3 system for inducing multi-exon skipping in DMD patient-derived iPSCs

DMD患者さん由来iPS細胞で複数のエクソンスキッピングを誘導するデュアルCRISPR-Cas3システムの開発. 京都大学プレスリリース. 2023-08-25.Exploring New Avenues in DMD Treatment: CRISPR-Cas3's Multi-Exon Skipping Approach. 京都大学プレスリリース. 2023-08-28.To restore dystrophin protein in various mutation patterns of Duchenne muscular dystrophy (DMD), the multi-exon skipping (MES) approach has been investigated. However, only limited techniques are available to induce a large deletion to cover the target exons spread over several hundred kilobases. Here, we utilized the CRISPR-Cas3 system for MES induction and showed that dual crRNAs could induce a large deletion at the dystrophin exon 45–55 region (∼340 kb), which can be applied to various types of DMD patients. We developed a two-color SSA-based reporter system for Cas3 to enrich the genome-edited cell population and demonstrated that MES induction restored dystrophin protein in DMD-iPSCs with three distinct mutations. Whole-genome sequencing and distance analysis detected no significant off-target deletion near the putative crRNA binding sites. Altogether, dual CRISPR-Cas3 is a promising tool to induce a gigantic genomic deletion and restore dystrophin protein via MES induction

Low immunogenicity of LNP allows repeated administrations of CRISPR-Cas9 mRNA into skeletal muscle in mice

筋ジストロフィーのゲノム編集治療を目指したLNP-mRNA輸送システムの開発. 京都大学プレスリリース. 2021-12-08.Nanotechnology for genome editing in multiple muscles simultaneously. 京都大学プレスリリース. 2021-12-08.Genome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal muscle tissues. In general, AAV vectors are used for in vivo delivery, but AAV injections cannot be repeated because of neutralization antibodies. Here we report a chemically defined lipid nanoparticle (LNP) system which is able to deliver Cas9 mRNA and sgRNA into skeletal muscle by repeated intramuscular injections. Although the expressions of Cas9 protein and sgRNA were transient, our LNP system could induce stable genomic exon skipping and restore dystrophin protein in a DMD mouse model that harbors a humanized exon sequence. Furthermore, administration of our LNP via limb perfusion method enables to target multiple muscle groups. The repeated administration and low immunogenicity of our LNP system are promising features for a delivery vehicle of CRISPR-Cas9 to treat skeletal muscle disorders

Anthropometrics estimates renal function

In recumbent elderly patients, creatinine clearance (eCCr) estimated by the Cockcroft-Gault (CG) equation may not necessarily reflect renal function. We aimed to develop a novel formula to revise the CG equation using anthropometric measurements in bedridden elderly patients and evaluate its clinical utility. The subjects included 77 bedridden Japanese patients aged ≥ 65, hospitalized at Naruto Yamakami Hospital. The actual CCr (mCCr) value was measured using the 24-hour urine collection method. Anthropometric data, such as skeletal muscle mass, body fat mass (BFM), and triceps skinfold thickness (TSF), were collected. We established a novel formula to estimate CCr(BFM) or CCr(TSF) by correcting the eCCr(Enz + 0.2) value with BFM or TSF. The stage of classification of renal dysfunctions in patients with eGFR(BFM) or eGFR(TSF) was equivalent to the GFR(control) based on the mCCr. Notably, the novel equation for eCCr based on TSF (eCCr(TSF)), dubbed the “Naruto” formula, can be useful to evaluate renal function in bedridden elderly patients without expensive equipment or additional costs. In this study, mCCr was considered to be the true renal function of the patient, but whether and to what extent mCCr correlates with inulin clearance is unknown

イオン ビーム スパッタホウ ニ ヨル Fe-Coケイ ハクマク ノ サクセイ ト ソノ ジキ トクセイ

Iron-cobalt alloy thin films (O～54at. % Co-Fe) were deposited by using an ion beam sputtering apparatus, and their magnetic properties were investigated in detail. All of the films have large saturation magnetization above 20 kG. The films deposited at substrate temperature Ts of about 75℃ have large perpendicular magnetic anisotropy field H_ (>110 Oe) and high coercive force Hc (>50 Oe). While, the increase of Ts leads a significant decrease in both H_ and Hc.The perpendicular magnetic anisotropy of the film deposited at Ts above 250℃ disappears completely, and the films with Co content of 50-54 at. % have the lowest Hc as low as 50e. The increase of Ts from 75℃ to 250℃ also causes the change in the internal stress of the films from compressive stress to tensile stress along with a growth of crystallites in the films. Anealing the films in a vacuum has nearly the same effect on the changes of the magnetic properties and internal stress of the films as the increase of Ts. These changes in magnetic properties with Ts or annealing temperature are considered to be mainly caused by the change of stress induced magnetic anisotropy energy, since the Fe-Co alloy film has a large positive magnetostriction constant

Crystallization and preliminary X-ray crystallographic analysis of rat calcineurin B homologous protein 1

Calcineurin B homologous protein 1 from rat was expressed in E. coli, purified and crystallized. A full set of X-ray diffraction data has been collected to 2.2 Å resolution using a synchrotron-radiation source