Search

CRISPR/Cas9 is a powerful genome editing system that has remarkably facilitated gene knockout and targeted knock-in. To accelerate the practical use of CRISPR/Cas9, however, it remains crucial to improve the efficiency, precision, and specificity of genome editing, particularly targeted knock-in, achieved with this system. To improve genome editing efficiency, researchers should first have a molecular assay that allows sensitive monitoring of genome editing events with simple procedures. In the current study, we demonstrate that genome editing events occurring in L1CAM, an X-chromosome gene encoding a cell surface protein, can be readily monitored using flow cytometry (FCM) in multiple human cell lines including neuroblastoma cell lines. The abrogation of L1CAM was efficiently achieved using Cas9 nucleases which disrupt exons encoding the L1CAM extracellular domain, and was easily detected by FCM using anti-L1CAM antibodies. Notably, L1CAM-abrogated cells could be quantified by FCM in four days after transfection with a Cas9 nuclease, which is much faster than an established assay based on the PIGA gene. In addition, the L1CAM-based assay allowed us to measure the efficiency of targeted knock-in (correction of L1CAM mutations) accomplished through different strategies, including a Cas9 nuclease-mediated method, tandem paired nicking, and prime editing. Our L1CAM-based assay using FCM enables rapid and sensitive quantification of genome editing efficiencies and will thereby help researchers improve genome editing technologies.

Abstract Tandem paired nicking (TPN) is a method of genome editing that enables precise and relatively efficient targeted knock-in without appreciable restraint by p53-mediated DNA damage response. TPN is initiated by introducing two site-specific nicks on the same DNA strand using Cas9 nickases in such a way that the nicks encompass the knock-in site and are located within a homologous region between a donor DNA and the genome. This nicking design results in the creation of two nicks on the donor DNA and two in the genome, leading to relatively efficient homology-directed recombination between these DNA fragments. In this study, we sought to identify the optimal design of TPN experiments that would improve the efficiency of targeted knock-in, using multiple reporter systems based on exogenous and endogenous genes. We found that efficient targeted knock-in via TPN is supported by the use of 1700–2000-bp donor DNAs, exactly 20-nt-long spacers predicted to be efficient in on-target cleavage, and tandem-paired Cas9 nickases nicking at positions close to each other. These findings will help establish a methodology for efficient and precise targeted knock-in based on TPN, which could broaden the applicability of targeted knock-in to various fields of life science.

Abstract Various biomarkers have been proposed for sepsis; however, only a few become the standard. We previously reported that plasma histidine-rich glycoprotein (HRG) levels decreased in septic mice, and supplemental infusion of HRG improved survival in mice model of sepsis. Moreover, our previous clinical study demonstrated that HRG levels in septic patients were lower than those in noninfective systemic inflammatory response syndrome patients, and it could be a biomarker for sepsis. In this study, we focused on septic patients and assessed the differences in HRG levels between the non-survivors and survivors. We studied ICU patients newly diagnosed with sepsis. Blood samples were collected within 24 h of ICU admission, and HRG levels were determined using an enzyme-linked immunosorbent assay. Ninety-nine septic patients from 11 institutes in Japan were included. HRG levels were significantly lower in non-survivors (n = 16) than in survivors (n = 83) (median, 15.1 [interquartile ranges, 12.7–16.6] vs. 30.6 [22.1–39.6] µg/ml; p

Abstract Background Respiratory compromise (RC) including hypoxia and hypoventilation is likely to be missed in the postoperative period. Integrated pulmonary index (IPI) is a comprehensive respiratory parameter evaluating ventilation and oxygenation. It is calculated from four parameters: end-tidal carbon dioxide, respiratory rate, oxygen saturation measured by pulse oximetry (SpO2), and pulse rate. We hypothesized that IPI monitoring can help predict the occurrence of RC in patients at high-risk of hypoventilation in post-anesthesia care units (PACUs). Methods This prospective observational study was conducted in two centers and included older adults (≥ 75-year-old) or obese (body mass index ≥ 28) patients who were at high-risk of hypoventilation. Monitoring was started on admission to the PACU after elective surgery under general anesthesia. We investigated the onset of RC defined as respiratory events with prolonged stay in the PACU or transfer to the intensive care units; airway narrowing, hypoxemia, hypercapnia, wheezing, apnea, and any other events that were judged to require interventions. We evaluated the relationship between several initial parameters in the PACU and the occurrence of RC. Additionally, we analyzed the relationship between IPI fluctuation during PACU stay and the occurrences of RC using individual standard deviations of the IPI every five minutes (IPI-SDs). Results In total, 288 patients were included (199 elderly, 66 obese, and 23 elderly and obese). Among them, 18 patients (6.3 %) developed RC. The initial IPI and SpO2 values in the PACU in the RC group were significantly lower than those in the non-RC group (6.7 ± 2.5 vs. 9.0 ± 1.3, p

There has been a great deal of research on cell division and its mechanisms; however, its processes still have many unknowns. To find novel proteins that regulate cell division, we performed the screening using siRNAs and/or the expression plasmid of the target genes and identified leucine zipper protein 1 (LUZP1). Recent studies have shown that LUZP1 interacts with various proteins and stabilizes the actin cytoskeleton; however, the function of LUZP1 in mitosis is not known. In this study, we found that LUZP1 colocalized with the chromosomal passenger complex (CPC) at the centromere in metaphase and at the central spindle in anaphase and that these LUZP1 localizations were regulated by CPC activity and kinesin family member 20A (KIF20A). Mass spectrometry analysis identified that LUZP1 interacted with death-associated protein kinase 3 (DAPK3), one regulator of the cleavage furrow ingression in cytokinesis. In addition, we found that LUZP1 also interacted with myosin light chain 9 (MYL9), a substrate of DAPK3, and comprehensively inhibited MYL9 phosphorylation by DAPK3. In line with a known role for MYL9 in the actin-myosin contraction, LUZP1 suppression accelerated the constriction velocity at the division plane in our time-lapse analysis. Our study indicates that LUZP1 is a novel regulator for cytokinesis that regulates the constriction velocity of the contractile ring. [ABSTRACT FROM AUTHOR]

Targeted knock-in supported by the CRISPR/Cas systems enables the insertion, deletion, and substitution of genome sequences exactly as designed. Although this technology is considered to have wide range of applications in life sciences, one of its prerequisites for practical use is to improve the efficiency, precision, and specificity achieved. To improve the efficiency of targeted knock-in, there first needs to be a reporter system that permits simple and accurate monitoring of targeted knock-in events. In the present study, we created such a system using the PIGP gene, an autosomal gene essential for GPI-anchor biosynthesis, as a reporter gene. We first deleted a PIGP allele using Cas9 nucleases and then incorporated a truncating mutation into the other PIGP allele in two near-diploid human cell lines. The resulting cell clones were used to monitor the correction of the PIGP mutations by detecting GPI anchors distributed over the cell membrane via flow cytometry. We confirmed the utility of these reporter clones by performing targeted knock-in in these clones via a Cas9 nickase-based strategy known as tandem paired nicking, as well as a common process using Cas9 nucleases, and evaluating the efficiencies of the achieved targeted knock-in. We also leveraged these reporter clones to test a modified procedure for tandem paired nicking and demonstrated a slight increase in the efficiency of targeted knock-in by the new procedure. These data provide evidence for the utility of our PIGP-based assay system to quantify the efficiency of targeted knock-in and thereby help improve the technology of targeted knock-in. [ABSTRACT FROM AUTHOR]

Tyrosol (Tyr) is a natural phenolic antioxidant with diverse biological activities. We compared the anti-inflammatory effects of intravenously administered Tyr versus prednisolone (PSL) in an endotoxin-induced uveitis (EIU) rat model. Intravenous administration of 100 mg/kg Tyr was performed 2 hr before, simultaneously and 2 hr after lipopolysaccharide (LPS) injection. Tyr treatment was associated with decreased inflammatory cell number, protein concentration, tumor necrosis factor (TNF)-α, PGE2 and NO levels in AqH and improvements in histopathologic evidence of EIU in ocular tissue at 24 hr after LPS injection. 100 mg/kg Tyr and 1 mg/kg PSL (administered on the same schedule as Tyr) had comparable anti-inflammatory effects. Taken together, Tyr may represent a promising therapeutic agent for the management of intraocular inflammatory diseases. [ABSTRACT FROM AUTHOR]

We evaluated the anti-inflammatory effect of tyrosol (Tyr) on endotoxin-induced uveitis (EIU) in rats. EIU was induced in male Lewis rats by subcutaneous injection of lipopolysaccharide (LPS). Tyr (10, 50 or 100 mg/kg) was intravenously injected 2 hr before, simultaneously and 2 hr after LPS injection. The aqueous humor (AqH) was collected 24 hr after LPS injection; the infiltrating cell number, protein concentration, and tumor necrosis factor (TNF)-α, prostaglandin (PG)-E2 and nitric oxide (NO) levels were determined. Histopathologic examination and immunohistochemical studies for nuclear factor (NF)-κB, inhibitor of κB (IκB)-α, cyclooxygenase (COX)-2 and inducible NO synthase (iNOS) in the iris--ciliary body (ICB) were performed at 3 or 24 hr after LPS injection. To further clarify the anti-inflammatory effects, RAW264.7 macrophages were stimulated with LPS in the presence or absence of Tyr. Tyr reduced, in a dose-dependent manner, the infiltrating cell number, protein concentration, and TNF-α, PGE2 and NO levels in AqH and improved histopathologic scores of EIU. Tyr also inhibited LPS-induced COX-2 and iNOS expression, IκB-α degradation and nuclear translocation of activated NF-κB in ICB. Tyr significantly suppressed inflammatory mediator production in the culture medium and COX-2 and iNOS expression and activated NF-κB translocation in LPS-stimulated RAW264.7 cells. These results suggest that Tyr suppresses ocular inflammation of EIU by inhibiting NF-κB activation and subsequent proinflammatory mediator production. [ABSTRACT FROM AUTHOR]