Mitochondria Play Essential Roles in Intracellular Protection against Oxidative Stress-Which Molecules among the ROS Generated in the Mitochondria Can Escape the Mitochondria and Contribute to Signal Activation in Cytosol?

Questions about which reactive oxygen species (ROS) or reactive nitrogen species (RNS) can escape from the mitochondria and activate signals must be addressed. In this study, two parameters, the calculated dipole moment (debye, D) and permeability coefficient (Pm) (cm s-1), are listed for hydrogen peroxide (H2O2), hydroxyl radical (•OH), superoxide (O2•-), hydroperoxyl radical (HO2•), nitric oxide (•NO), nitrogen dioxide (•NO2), peroxynitrite (ONOO-), and peroxynitrous acid (ONOOH) in comparison to those for water (H2O). O2•- is generated from the mitochondrial electron transport chain (ETC), and several other ROS and RNS can be generated subsequently. The candidates which pass through the mitochondrial membrane include ROS with a small number of dipoles, i.e., H2O2, HO2•, ONOOH, •OH, and •NO. The results show that the dipole moment of •NO2 is 0.35 D, indicating permeability; however, •NO2 can be eliminated quickly. The dipole moments of •OH (1.67 D) and ONOOH (1.77 D) indicate that they might be permeable. This study also suggests that the mitochondria play a central role in protecting against further oxidative stress in cells. The amounts, the long half-life, the diffusion distance, the Pm, the one-electron reduction potential, the pKa, and the rate constants for the reaction with ascorbate and glutathione are listed for various ROS/RNS, •OH, singlet oxygen (1O2), H2O2, O2•-, HO2•, •NO, •NO2, ONOO-, and ONOOH, and compared with those for H2O and oxygen (O2). Molecules with negative electrical charges cannot directly diffuse through the phospholipid bilayer of the mitochondrial membranes. Short-lived molecules, such as •OH, would be difficult to contribute to intracellular signaling. Finally, HO2• and ONOOH were selected as candidates for the ROS/RNS that pass through the mitochondrial membrane.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

CRISPR-Based Epigenome Editing and Genome Wide Screening Define Mediators of Chemotherapy Response in Glioblastoma

PURPOSE/OBJECTIVE(S)

Alkylating chemotherapies exhibit survival benefit for patients with glioblastoma (GBM), the most common malignant primary brain tumor. CRISPRoff is a programmable epigenetic memory writer that stably and heritably silences any gene through DNA methylation. Epigenetic silencing of MGMT via promoter methylation is predictive of response to alkylating agents as well as prognostic for progression free and overall survival. Here we performed epigenome editing using CRISPRoff to stably silence MGMT through induced promoter methylation, as a therapeutically tractable approach for potentiating GBM to temozolomide (TMZ) or lomustine (CCNU). We then used genome-wide engineered CRISPR/Cas9 systems to broadly define sensitizers of GBM cells to alkylating agents, as a platform to discover novel sensitizing targets.

MATERIALS/METHODS

Targeted epigenome editing was performed through electroporation of modified mRNAs encoding CRISPRoff machinery comprising deactivated Cas9 fused to a DNA methyltransferase complex, combined with sgRNAs, into MGMT unmethylated GBM cell lines (LN18, T98G) and then treated with either vehicle, TMZ, or CCNU. Parallel experiments were performed through electroporation of sgRNA/Cas9 ribonucleoproteins. Gene silencing was assessed using bisulfite targeted sequencing, RT-qPCR, and western blot. Drug sensitization was determined using luminescent cell viability assays. Genome-wide CRISPR interference (CRISPRi) screens were performed in triplicate cultures.

RESULTS

Epigenomic silencing of the MGMT promoter through CRISPRoff-induced methylation reduced MGMT transcript levels by 96.7% and generated up to 88-fold sensitization to TMZ mediated cell death in GBM cells, with IC50 superior to GBM cells with baseline methylated MGMT. In addition, CRISPRoff of MGMT induced 20-fold sensitization to CCNU. CRISPRoff methylation of MGMT was equivalent to CRISPR/Cas9 homozygous deletion of the MGMT gene for drug sensitization and was superior to polyclonal Cas9 mediated deletion of MGMT by a factor of 10. To define additional mediators of chemotherapy response in GBM, CRISPRi screens revealed 185 and 266 genetic sensitizers to TMZ treatment in LN18 and T98G cells, respectively, in addition to validating MGMT. One hundred eighty and 238 sensitizers to CCNU were identified in LN18 and T98G cells, respectively. TMZ sensitizing genes conserved across cell lines were enriched for the ATR (i.e., BCRA2), DNA repair (i.e., REV1), and cell cycle pathways (i.e., PSMD13), while CCNU sensitizing genes were enriched for the Fanconi anemia pathway (i.e., FANCI, FANCD2). In contrast, gene hits that resulted in resistance to alkylating agents were enriched for the mismatch repair pathway (i.e., MSH2, PMS2).

CONCLUSION

We integrate targeted epigenome editing with unbiased genome-wide approaches to build a novel discovery and therapeutic platform in glioblastoma, a framework that is well suited for targeting diseases with known or suspected epigenetic vulnerabilities.

Identifying Gene-Treatment Interactions and Targetable Radiation Vulnerabilities in Glioblastoma through Coupling of In Vivo CRISPR Perturbation and Single Cell Transcriptomics

PURPOSE/OBJECTIVE(S)

Glioblastoma (GBM) is an incurable brain tumor comprised of dynamic malignant cell states and microenvironment components that underlie treatment resistance. Here we use genome-wide CRISPR/Cas9 functional genomics to define biological drivers and therapeutic vulnerabilities across human and mouse GBM models. To interrogate these mechanisms in the context of the tumor microenvironment and in vivo physiology, we established in vivo Perturb-seq intracranially, a technique coupling functional genomics with single cell transcriptomics, where each cell is an individual experiment.

MATERIALS/METHODS

Orthotopic intracranial tumor models were established using human (GBM6, GBM43) or mouse (GL261, SB28) GBM cells stably expressing CRISPR interference (CRISPRi) machinery. Perturb-seq target selection for phenotyping of gene-treatment interactions was performed using genome-wide CRISPRi screens ± radiotherapy in cell cultures. Dual sgRNA lentivirus libraries were transduced either ex vivo prior to intracranial GBM cell transplantation or in vivo using intratumor convection enhanced delivery (CED). Transcriptional phenotyping was performed using single-cell RNA-seq with CRISPR direct capture following focal brain radiotherapy (2 Gy x 5) or mock treatment. GBM cell states were validated using single-nucleus RNA-seq data from 86 primary-recurrent patient-matched GBMs. Mechanistic and functional validation was performed using small molecule inhibitors, immunohistochemistry, clonogenic assays, and in vivo survival experiments.

RESULTS

In vivo Perturb-seq ± radiotherapy of 48 genes underlying GBM radiotherapy responses, which were enriched for DNA damage response and metabolic pathways, was performed in > 425,000 single cells. Radiotherapy induced 16 distinct GBM cell states, and genetic perturbations reprogrammed these cell states in a treatment-dependent fashion. Quantitative modeling of gene/radiotherapy interactions using high dimensional manifolds revealed in vivo-specific genetic dependencies. We revealed a critical role for Prkdc, the catalytic subunit of DNA-dependent protein kinase (DNA-PK), as a radiotherapy sensitizer through regulation of cell intrinsic growth and oxidative stress pathways, and cell extrinsic interferon and signaling pathways that altered cell-cell interactions in vivo. These pathways were also disrupted in single-nucleus RNA-seq analysis of post-radiotherapy human GBM tumors. Inhibition of Prkdc using a Food and Drug Administration approved small molecule sensitized GBM cells to radiotherapy and extended survival in mice harboring human intracranial xenografts.

CONCLUSION

We establish in vivo Perturb-seq in orthotopic GBM models as a platform for simultaneous functional genomic discovery and characterization of therapeutic targets, revealing an underappreciated role for Prkdc in GBM tumors in vivo that is targetable using small molecules. These tools are adaptable for a wide range of disease models and treatment modalities.

Quenching effect of cerium oxide nanoparticles on singlet oxygen: validation of the potential for reaction with multiple reactive oxygen species

Here we studied cerium oxide nanoparticles (nanoceria) as an agent for the future treatment of oxidative damage by validating and evaluating its scavenging activity towards reactive oxygen species (ROS) in vitro. Nanoceria has been shown to mimic the activities of superoxide dismutase and catalase, degrading superoxide (O2•-) and hydrogen peroxide (H2O2). We examined the antioxidative activity of nanoceria, focusing on its ability to quench singlet oxygen (1O2) in an aqueous solution. Electron paramagnetic resonance (EPR) was used to determine the rates of second-order reactions between nanoceria and three ROS (1O2, O2•-, and H2O2) in aqueous solution, and its antioxidative abilities were demonstrated. Nanoceria shows a wide range of ultraviolet-light absorption bands and thus 1O2 was produced directly in a nanoceria suspension using high-frequency ultrasound. The quenching or scavenging abilities of nanoceria for 1O2 and hypoxanthine-xanthine oxidase reaction-derived O2•- were examined by EPR spin-trapping methods, and the consumption of H2O2 was estimated by the EPR oximetry method. Our results indicated that nanoceria interact not only with two previously reported ROS but also with 1O2. Nanoceria were shown to degrade O2•- and H2O2, and their ability to quench 1O2 may be one mechanism by which they protect against oxidative damage such as inflammation.

Protective effects of 2-aminoethylthiosulfuric acid and structurally analogous organosulfur compounds against ionizing radiation

High efficacy and minimal toxicity radioprotectors are desirable options for the hazards posed by nuclear medical and energy technologies and the dangers presented by nuclear weapons in an unstable global situation. Although cysteamine is an effective radioprotector, it has considerable toxicity. In this study, the protective effects of the less toxic organosulfur compounds 2-aminoethylthiosulfate (AETS), thiotaurine (TTAU), and hypotaurine (HTAU) against X-ray damage in mice were compared with that of cysteamine. Intraperitoneal injection of either AETS or cysteamine (2.2 mmol/kg body weight) 30 min before X-ray irradiation (7.0 Gy) provided 100% survival for 30 days, limited the decrease in erythrocytes and neutrophils over 9 days, and reduced damage to bone marrow and spleen over 9 days. Neither TTAU nor HTAU provided any protection. In mice, 30 min after AETS administration, non-protein thiol content increased in the spleen, indicating cysteamine generation by AETS hydrolysis, the active protective species of AETS. All examined compounds scavenged ^•OH under diffusion control in aqueous solution, which is inconsistent with the difference in the protective effects among the compounds. The results indicate that AETS protects animals from ionizing radiation by several mechanisms, including scavenging ^•OH as cysteamine.

Calmodulinopathy is a common cause of critical cardiac phenotypes in fetus and infancy

Background

Cardiac calmodulinopathy is a life-threatening arrhythmia syndrome which presents several phenotypes of inherited primary arrhythmia syndrome (IPAS), and caused by mutations in calmodulin-encoded genes (CALM1–3). We aimed clarify the frequency and their clinical characteristics of calmodulinopathy in our IPAS cohort.

Methods

By using next generation sequencing, we screened arrhythmia related genes including calmodulin-encoding genes in 322 unrelated symptomatic children (0–12 years) who were suspected as IPAS; they included 40 cases with lethal arrhythmic attacks (LAE) under 6-year-old. After gene screening, we investigated their physiological and clinical characteristics about mutation carriers.

Results

Among 322 children, we identified 6 mutations of calmodulin-encoded genes in 9 probands (2.8%); one CALM1 in 2 probands (N98S), and 5 CALM2 in 7 probands (E46K, D96V, D96G, N98S, E141K). Their clinical diagnoses were long QT syndrome (LQTS, n=4), catecholaminergic polymorphic ventricular tachycardia (CPVT, n=3) and both (n=2). Their age of diagnosis ranges at 0–9 with the median of 5 years. There were three major clinical phenotypes; 1) CALM2-D96V, and E141K: two infants with advanced atrio-ventricular block, significant QTc prolongation, severe heart failure from their fetal period – both of them deceased within 1.5-year-old. Their clinical phenotypes resembled classical Timothy syndrome caused by CACNA1C mutations. 2) CALM1-N98S (n=2), CALM2-N98S (n=2), and CALM2-D96G: four preschoolers with LAEs and one syncope: all of them were 3–5 years old. In addition, a T wave morphology of CALM2-D96G carrier was very similar to LQT1. 3) CALM2-E46K (n=2): two were first diagnosed with neurological and developmental disorders, and showed phenotype of CPVT: their cardiac phenotypes were milder compared with that of 1) or 2). Overall, these phenotypes seemed to be mutation specific (indicated in figure). Their cardiac features were severer, and the onset of LAEs was earlier compared with other genotypes of LQTS/CPVT. As the treatment, β-blocker was effective for control of LAEs.

Conclusion

Cardiac calmodulinopathy presented serious and potentially lethal phenotypes in fetus or infancy. To prevent cardiac death in them, we must correctly diagnose and start the treatment as earlier as possible.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): MEXT KAKENHI from the Ministry of Education, Culture, Sports, Science, and Technology of Japan

Commentary for an article on spin trapping of superoxide and hydroxyl radical: Practical aspect

This commentary describes a highly cited paper by Eli Finkelstein, Gerald M. Rosen, and Elmer J. Raukman that appeared in Archives of Biochemistry and Biophysics published in 1980. They reviewed many reports being regularly appearing in the literature describing spin trapping and hydroxyl radicals from various sources and contributed to the development and progress that has been made in oxidative stress research.

Characteristics and outcome of suspected cerebrovascular disease in dogs: 66 cases (2009-2016)

OBJECTIVES

To characterise the clinical signs of suspected cerebrovascular disease in dogs.

MATERIALS AND METHODS

Medical records of one hospital were searched from November 2009 to December 2016 for dogs that suffered of cerebrovascular disease. We diagnosed cerebrovascular disease based on acute onset, clinical signs and magnetic resonance imaging findings. The medical history, clinical signs, concurrent disease, area of infarction, cerebrospinal fluid results, month at onset and outcome were investigated in the cerebrovascular disease group and in a control group (dogs with brain disorders other than cerebrovascular disease).

RESULTS

A total of 122 CVD cases were extracted from the 5312 patients that visited during the study period. Of these 122 cases, 66 (1.2%) matched the subject selection criteria of our study and were included in the analysis. Forebrain infarction was observed in 51 of 66 cases, of which 24 (47.1%) suffered from seizures. The number of dogs diagnosed with cerebrovascular disease was disproportionately high in August (nine of 59 cases) and December (13 of 59 cases). In the outcome survey, deterioration was observed in 11 of 55 cases.

CLINICAL SIGNIFICANCE

Seizure is an important clinical sign of cerebrovascular disease in dogs. There was a significant seasonal variation in the number of dogs diagnosed with cerebrovascular disease in Japan. Clinical features observed in this report differ from those of previous reports and highlight the need for additional research in this area.

Effects of reaction environments on radical-scavenging mechanisms of ascorbic acid

The effects of reaction environments on the radical-scavenging mechanisms of ascorbic acid (AscH2) were investigated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) as a reactivity model of reactive oxygen species. Water-insoluble DPPH• was solubilized by β-cyclodextrin (β-CD) in water. The DPPH•-scavenging rate of AscH2 in methanol (MeOH) was much slower than that in phosphate buffer (0.05 M, pH 7.0). An organic soluble 5,6-isopropylidene-l-ascorbic acid (iAscH2) scavenged DPPH• much slower in acetonitrile (MeCN) than in MeOH. In MeOH, Mg(ClO4)2 significantly decelerated the DPPH•-scavenging reaction by AscH2 and iAscH2, while no effect of Mg(ClO4)2 was observed in MeCN. On the other hand, Mg(ClO4)2 significantly accelerated the reaction between AscH2 and β-CD-solubilized DPPH• (DPPH•/β-CD) in phosphate buffer (0.05 M, pH 6.5), although the addition of 0.05 M Mg(ClO4)2 to the AscH2-DPPH•/β-CD system in phosphate buffer (0.05 M, pH 7.0) resulted in the change in pH of the phosphate buffer to be 6.5. Thus, the DPPH•-scavenging reaction by iAscH2 in MeCN may proceed via a one-step hydrogen-atom transfer, while an electron-transfer pathway is involved in the reaction between AscH2 and DPPH•/β-CD in phosphate buffer solution. These results demonstrate that the DPPH•-scavenging mechanism of AscH2 are affected by the reaction environments.

In vivo ESR imaging of redox status in mice after X-ray irradiation, measured by acyl-protected hydroxylamine probe, ACP

More detailed investigations on the in vivo redox status are needed to elucidate the mechanisms contributing to damage caused by ionizing radiation. In the present study, the in vivo redox status of mice was examined using in vivo electron spin resonance (ESR) imaging after an intraperitoneal injection of 1-acetoxy-3-carbamoyl-2,2,5,5-tetramethylpyrrolidine (ACP) as a probe. ACP is easily hydrolyzed to its hydroxylamine form in the mouse body, and the interconversion between hydroxylamine and the corresponding nitroxyl radical reflects the biological redox status. Liver damage, based on changes in liver weight and plasma aspartate aminotransferase levels, was detected in mice 4 days after X-ray irradiation at 7.5 Gy. ESR imaging showed that the signal intensity of the nitroxyl radical was high at the liver area in both damaged and healthy mice after administration of ACP. Whereas the signal decayed at the liver area for healthy mouse, the decay was negligible in damaged mice. Unlike healthy mouse, signal in the chest for damaged mouse increased with time. The distribution of the sum of hydroxylamine and the nitroxyl radical was similar in damaged and healthy mice. X-ray irradiation slightly lowered the reduction activity of the liver microsomal fraction for the nitroxyl radical. Thiobarbituric acid reactive substances in the liver were higher in damaged mice than in healthy mice; however, no significant differences were noted in reduced glutathione. The present results indicate that the redox status of mice exposed to X-ray irradiation is more oxidative than that in healthy mice.

Splice site mutation of LMNA causes severe dilated cardiomyopathy via strong dominant reduction of total lamin expression

Objective

LMNA is a known causative gene of dilated cardiomyopathy (DCM) and familial cardiac conduction disturbance (CCD). Genetic variants affecting the pre-mRNA splicing process often lead to premature stop codons and result in nonsense-mediated mRNA decay (NMD), followed by degradation of mutated alleles. The misssense variant LMNA c. 936G&gt;C was previously reported in a French family affected by muscular dystrophy, CCD, and DCM, but no detailed analysis has been performed. We so far identified the same variant in two Japanese families affected by CCD and DCM. In this study, we investigated the molecular consequences of the variant located at the last codon of LMNA exon5 to demonstrate its pathogenicity.

Methods

Genomic DNA and total RNA were isolated from patients' peripheral blood lymphocytes or cardiac tissue. LMNA-coding exons were screened by direct sequencing. Complementary DNAs (cDNAs) were generated by reverse transcription PCR from RNA. Quantitative PCR (qPCR) was performed to quantify the LMNA cDNA amount by using specific primers for lamins A and C. The protein expressions of both isoforms were analyzed by western blotting.

Results

We detected the heterozygous LMNA c.936 G&gt;C (p. Q312H) variant at the end of exon 5 by genomic DNA sequencing in two unrelated Japanese families (figure. pedigree) affected by DCM and CCD. In a genomic database survey, we did not find the variant in either gnomAD, TogoVar, or the Human Genetic Variation Database. The two commonly used splice site predictor tools, NetGene2 and FSPLICE, estimated that this site was a splice donor site. Sequencing of cDNA demonstrated that the mutated allele was absent. By qPCR assay, we confirmed a 90% reduction in LMNA cDNA. Western blot analysis revealed that lamin A and C expression was reduced far more than 50% (figure. western blot).

Conclusions

We report a LMNA missense mutation found in two families, which disrupts a normal splicing site, leads to NMD, and resulted in severe cardiac laminopathy. The drastic reductions of lamin expression at the cDNA and protein levels suggested that other co-existing mechanisms may also have suppressed the expression of the healthy wild type allele.

Pedigree and western blot assay

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science KAKENHI

Elimination of senescent cells targeting Senescence associated glycoprotein (SAGP) improved the ageing-associated diseases and extended the lifespan

 

Cellular senescence entails an irreversible growth arrest and a pro-inflammatory secretory phenotype, which contributes to aging-associated disorders such as atherosclerosis and diabetes, however, underlying mechanisms are largely unknown. In this study, we identified a novel protein, senescence-associated glycoprotein (SAGP), as a biomarker of cellular senescence and we also found that elimination of senescent cells targeting SAGP attenuated aging-associated disorders such as atherosclerosis, diabetes and frailty.

First, we identified that SAGP as a senescent marker by microarray analysis of senescent human endothelial cells compared with young endothelial cells. The expression of SAGP was significantly increased in the aorta of chronological aging mice and ApoE-knockout mice. Then we measured SAGP expression in the patients registered in our hospital and found that mean SAGP expression was significantly higher in patients with atherosclerotic diseases compared to patients without atherosclerotic diseases. These data suggest that SAGP would become the novel marker of cellular senescence and/or aging-associated disorders.

We found SAGP co-localized with lysosome and bound to V-ATPase, proton pump in the acid organelles such as lysosome. The electron microscopy analysis revealed that the dysfunctional lysosomes were accumulated in SAGP knockdown endothelial cell. The genetic deletion of SAGP resulted in the increase of lysosomal pH and the suppression of mitochondrial autophagy, mitophagy. And this associated with the high level of mitochondrial reactive oxygen species (ROS) and promoted premature senescence in human endothelial cells. These data suggest that SAGP was induced by the lysosomal stress in the senescent cells to protects senescent cells by maintaining the lysosomal homeostasis.

Recently, it is reported that elimination of senescent cells (senolysis) reversibly improved pathological aging phenotypes and also extended the lifespan. We established senolytic therapy targeting SAGP. We generated SAGP-DTR (diphtheria toxin receptor) transgenic mice, in which we could eliminate the SAGP- positive senescent cells using DT (diphtheria toxin). We found elimination of SAGP positive senescent cells significantly reduced the atherosclerotic plaque burden in the aorta of ApoE-KO mice and improved the glucose metabolism of dietary obese mice, indicating that SAGP could be a useful target for senolytic therapy. For clinical implication, we then developed a cytotoxic vaccine targeting SAGP. Treatment with SAGP vaccine successfully eliminated SAGP positive senescent cells and attenuated atherosclerosis and metabolic dysfunction. Surprisingly, administration of SAGP vaccine to Zmpste24-KO mice, premature aging mice, extended the lifespan. These data indicate that targeting SAGP-positive cells could be a novel strategy for senolytic therapy.

Effect of SAGP vaccine

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research by Japan Society for the Promotion of Science (JSPS)

Social frailty provides additive prognostic impact on one-year outcome in aged patients with congestive heart failure

Background

Frailty is associated with multisystem declines in physiologic reserve and increased vulnerability to stressors, resulting in increased risks of adverse clinical outcomes in patients with heart failure (HF). Although frailty is conceptualized as an accumulation of deficits in multiple areas, most of the studies have focused mainly on physical frailty, and the social domains is one of the least investigated area.

Objectives

We prospectively evaluated the incidence and prognostic implication of social frailty (SF) in older patients with HF.

Methods

The FRAGILE-HF is a multicenter, prospective cohort study including patients hospitalized for HF and aged ≥65 years old. We defined SF by Makizako's 5 items, which are 5 questions proposed and validated to be associated with future disability. The primary endpoint of this study was a composite of death from any cause and rehospitalization due to HF. The impact of SF on all-cause mortality alone was also evaluated.

Results

Among 1,240 hospitalized HF patients, 5 simple questions revealed that 825 (66.5%) were in SF. During 1-year observation period after the discharge, the combined endpoint was observed in 399 (32.2%) patients, and 145 (11.7%) patients died. Kaplan-Meier analysis showed that SF patients had significantly higher rates of both the combined endpoint and all-cause mortality than those without SF (Log-rank test: p&lt;0.05 for both, Figures). Moreover, SF remained independently associated with higher event rate of the combined endpoint (hazard ratio: 1.30; 95% confidence interval: 1.02 to 1.66; p=0.038) and all-cause mortality (hazard ratio: 1.53; 95% confidence interval: 1.01 to 2.30; p=0.044), even after adjusting for other covariates. Significant incremental prognostic value was shown when information on social frailty was added to known risk factors for combined endpoint (NRI: 0.189, 95% confidence interval: 0.063–0.316, p=0.003) and all-cause mortality (NRI: 0.234, 95% confidence interval: 0.073–0.395, p=0.004).

Conclusions

Among older hospitalized patients with heart failure, two-thirds of the population was with SF. Evaluating SF provides additive prognostic information in elderly patients with heart failure.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Novartis Pharma Research Grants, Japan Heart Foundation Research Grant

Semi-Dirac Transport and Anisotropic Localization in Polariton Honeycomb Lattices

Compression dramatically changes the transport and localization properties of graphene. This is intimately related to the change of symmetry of the Dirac cone when the particle hopping is different along different directions of the lattice. In particular, for a critical compression, a semi-Dirac cone is formed with massless and massive dispersions along perpendicular directions. Here we show direct evidence of the highly anisotropic transport of polaritons in a honeycomb lattice of coupled micropillars implementing a semi-Dirac cone. If we optically induce a vacancylike defect in the lattice, we observe an anisotropically localized polariton distribution in a single sublattice, a consequence of the semi-Dirac dispersion. Our work opens up new horizons for the study of transport and localization in lattices with chiral symmetry and exotic Dirac dispersions.

A large kinetic isotope effect in the reaction of ascorbic acid with 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO˙) in aqueous buffer solutions

A large kinetic isotope effect (KIE, kH/kD) of 12.8 was observed for the hydrogen-transfer reaction from ascorbic acid to 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO˙) in a phosphate buffer solution (0.05 M, pH/pD 7.0) at 298 K. The isotopic difference in the activation energies (6.8 kJ mol-1) determined from the temperature dependence of the KIE suggests that quantum mechanical tunneling may partly play a role in the reaction, although the isotopic ratio of the Arrhenius prefactor (AH/AD = 0.86) is within the semiclassical limits.

5892Elimination of cells expressing Senescence associated glycoprotein (SAGP) attenuates the atherosclerotic diseases

Cellular senescence is defined as a state of irreversible growth arrest and is accompanied by changes of both cell morphology and gene expression. Although accumulation of senescent vascular endothelial cells impair the vessel homeostasis and promote atherosclerotic diseases, underlying mechanisms are largely unknown. In this study, we identified a novel protein, senescence-associated glycoprotein (SAGP), as a biomarker of cellular senescence and we found modulation of SAGP or elimination of senescent cells targeting SAGP would become a novel therapy for atherosclerotic diseases.

We found that SAGP expression was significantly increased in human endothelial cells undergoing replicative senescence compared with young endothelial cells. We also found SAGP expression in aorta was significantly increased both in chronological aging mice or ApoE knockout mice. Furthermore, we measured SAGP expression in patients registered in our hospital and found that mean SAGP expression was significantly higher in patients with atherosclerotic diseases compared to patients without atherosclerotic diseases.These data suggest that SAGP would become a novel cellular senescence and/or atherosclerotic disease marker.

Genetic deletion of SAGP resulted in high level of mitochondrial reactive oxygen species (ROS) and promoted premature senescence in human endothelial cells. And this associated with suppression of mitochondrial autophagy, mitophagy. We found SAGP co-localized with lysosome by immunocytochemistry. In addition, the electron microscopy analysis revealed that the dysfunctional lysosomes were accumulated in SAGP knockdown endothelial cell, suggesting that SAGP maintain lysosomal homeostasis.

Next, wegenerated ApoE-KO/ SAGP overexpression mice and found that atherosclerotic plaque burden was attenuated in these double-transgenic mice. In contrast, SAGP/ApoE double knockout mice showed progression in atherosclerosis. These data suggest that modulation of SAGPwould become a new therapeutic target for atherosclerotic diseases.

SAGP vaccine

Recently, it is reported that elimination of senescent cells (senolysis) reversibly improved pathological aging phenotypes and also extended the lifespan. We have taken another approach for atherosclerotic diseases, senolytic therapy targeting SAGP. We generated SAGP-DTR (diphtheria toxin receptor) transgenic mice, in which we could eliminate the SAGP- positive senescent cells using DT (diphtheria toxin). We found elimination of SAGP positive senescent cells significantly reduced the atherosclerotic plaque burden, indicating that SAGP would become a useful target for senolytic therapy. We then developed a cytotoxic vaccine targeting SAGP. Treatment with SAGP vaccine successfully eliminated SAGP positive senescent cells. Administration of SAGP vaccine to ApoE-KO mice significantly reduced atherogenesis. These data indicate that targeting SAGP-positive cells could become a strategy for senolytic therapy.

P4764Relationship of the duration of pulmonary vein isolation-refractory non-paroxysmal atrial fibrillation to the middle- to long-term outcome of the ExTRa Mapping-guided ablation

Introduction

It is reported that for patients with non-paroxysmal (persistent or long-standing persistent) atrial fibrillation (Non-PAF), extended ablation to atrial walls in addition to pulmonary vein isolation (PVI) did not improve the long-term outcome. On the other hand, modulation of Non-PAF drivers (or perpetuators) has been proposed as one of the alternative effective ablation strategies for Non-PAF.

Purpose

To clarify whether the rotor ablation under online real-time high-density phase mapping system is effective for PVI-refractory Non-PAF ablation.

Methods

Under such circumstances, our academic group had recently developed the online real-time high-density phase mapping system (ExTRa Mapping™) by industrial alliance. The phase map moving images were based on 41 intra-atrial bipolar signals recorded by a 20-pole spiral-shaped catheter (2.5 cm in diameter) and on in silicorapid prediction of spatio-temporal atrial excitations (artificial intelligence system). Then we applied the ExTRa Mapping to clinical practice in order to directly visualize rotors in patients with Non-PAF, and investigated the middle- to long-term outcome of the ExTRa Mapping-guided rotor ablation (ExTRa-ABL).

Results

Thirty-eight patients (63±8 y/o, 30 males) with Non-PAF demonstrating refractoriness to PVI were enrolled in this study. Ablation for cavo-tricuspid isthmus and/or superior vena cava isolation was additionally performed at physicians' discretion. After these procedures, the ExTRa-ABL was performed in order to modify Non-PAF substrates, causing rotor control. The modification of the rotors was evaluated by re-mapping with the use of the ExTRa Mapping at the end of each ablation session. Patients were followed at 1, 3, 6 months and every year after the procedure. All of them were followed for 21±8 months. During the follow-up period, Non-PAF was recurred in only 8 of 38 (21%). Furthermore, we found if PVI-refractory Non-PAF duration was shorter than 6 years, the non-recurrence rate remained ≥80% (see Figure), which was markedly better outcome comparing with previous reports with regard to Non-PAF ablation.

Figure 1

Conclusion

Comparing with conventional Non-PAF ablation strategies, our novel approach with the use of the online real-time high-density phase mapping system might improve medium- to long-term outcome of PVI-refractory Non-PAF treatment.

Reactivity of redox sensitive paramagnetic nitroxyl contrast agents with reactive oxygen species

The reactivity of nitroxyl free radicals, 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) and 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CmP), with reactive oxygen species (ROS) were compared as typical 6-membered and 5-membered ring nitroxyl compounds, respectively. The reactivity of the hydroxylamine forms of both these nitroxyl radicals (TEMPOL-H and CmP-H) was also assessed. Two free radical species of ROS, hydroxyl radical (^•OH) and superoxide (O₂^•−), were subjected to a competing reaction. ^•OH was generated by UV irradiation from an aqueous H₂O₂ solution (H₂O₂-UV system), and O₂^•− was generated by a reaction between hypoxanthine and xanthine oxidase (HX-XO system). ^•OH and O₂^•− generated by the H₂O₂-UV and HX-XO systems, respectively, were measured by electron paramagnetic resonance (EPR) spin-trapping, and the amount of spin adducts generated by each system was adjusted to be equal. The time courses of the one-electron oxidation of TEMPOL, CmP, TEMPOL-H, and CmP-H in each ROS generation system were compared. A greater amount of TEMPOL was oxidized in the HX-XO system compared with the H₂O₂-UV system, whereas the reverse was observed for CmP. Although the hydroxylamine forms of the tested nitroxyl radicals were oxidized evenly in the H₂O₂-UV and HX-XO systems, the amount of oxidized CmP-H was approximately 3 times greater compared with TEMPOL-H.

Gerinnungsbestimmungen am Zentrifugalanalysator - Messungen mit chromogenen Substraten und mit der Fibringerinnung

Ziel aller traditionellen Gerinnungstests ist die Fibrinogenumwandlung in Fibrin durch Thrombin. Die Gerinnselbildung wird entweder mechanisch oder photooptisch gemessen. Die Entwicklung chromogener Substrate zur Bestimmung von Gerinnungsenzymen hat eine spektrophotometrische Erfassung der Enzymreaktionen ermöglicht, die zur Automatisierung der Analysen mittels Zentrifugalanalysatoren im klinisch chemischen Laboratorium geführt hat.

Das von Instrumentation Laboratory (IL) entwickelte Automated Coagulation Laboratory (ACL)-System bietet Zentrifugalanalysatoren, die nicht nur Fibringerinnungstests, sondern auch chromogene Substrattests weitgehend automatisch durchführen (ACL 200, und 300 und 300 Research). Die Tests sind bei den 200und 300-Geräten vorprogrammiert, mit dem 300-Research-Gerät ist dagegen diese Vorprogrammierung zu umgehen. Somit können mit dem Gerät fast unbegrenzt neue Einphasenoder Zweiphasentests unter Verwendung von Gerinnungsverfahren oder chromogenen Substraten entwickelt werden. Das ACL-System ist einfach zu bedienen, hat eine ausgezeichnete Präzision und Reproduzierbarkeit und wirkt durch Automatisierung und niedrige Testvolumina kostendämpfend.

CCAT1 and CCAT2 long noncoding RNAs, located within the 8q.24.21 'gene desert', serve as important prognostic biomarkers in colorectal cancer

Background

8q24.21 is a frequently amplified genomic region in colorectal cancer (CRC). This region is often referred to as a 'gene desert' due to lack of any important protein-coding genes, highlighting the potential role of noncoding RNAs, including long noncoding RNAs (lncRNAs) located around the proto-oncogene MYC. In this study, we have firstly evaluated the clinical significance of altered expression of lncRNAs mapped to this genomic locus in CRC.

Patients and methods

A total of 300 tissues, including 280 CRC and 20 adjacent normal mucosa specimens were evaluated for the expression of 12 lncRNAs using qRT-PCR assays. We analyzed the associations between lncRNA expression and various clinicopathological features, as well as with recurrence free survival (RFS) and overall survival (OS) in two independent cohorts.

Results

The expression of CCAT1, CCAT1-L, CCAT2, PVT1, and CASC19 were elevated in cancer tissues (P = 0.039, <0.001, 0.018, <0.001, 0.002, respectively). Among these, high expression of CCAT1 and CCAT2 was significantly associated with poor RFS (P = 0.049 and 0.022, respectively) and OS (P = 0.028 and 0.015, respectively). These results were validated in an independent patient cohort, in which combined expression of CCAT1 and CCAT2 expression was significantly associated with a poor RFS (HR:2.60, 95% confidence interval [CI]: 1.04-6.06, P = 0.042) and a poor OS (HR:8.38, 95%CI: 2.68-37.0, P < 0.001). We established a RFS prediction model which revealed that combined expression of CCAT1, CCAT2, and carcinoembryonic antigen was a significant determinant for efficiently predicting RFS in stage II (P = 0.034) and stage III (P = 0.001) CRC patients.

Conclusions

Several lncRNAs located in 8q24.21 locus are highly over-expressed in CRC. High expression of CCAT1 and CCAT2 significantly associates with poor RFS and OS. The expression of these two lncRNAs independently, or in combination, serves as important prognostic biomarkers in CRC.

Aluminium ion-promoted radical-scavenging reaction of methylated hydroquinone derivatives

The effect of the aluminium ion (Al(3+)) on the scavenging reaction of a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙), as a reactivity model of reactive oxygen species, with hydroquinone (QH2) and its methylated derivatives (MenQH2, n = 1-4) was investigated using stopped-flow and electrochemical techniques in a hydroalcoholic medium. The second-order rate constants (k) for the DPPH˙-scavenging reaction of the hydroquinones increased with the increasing number of methyl substituents. Upon addition of Al(3+), the k values significantly increased depending on the concentration of Al(3+). Such an accelerating effect of Al(3+) on the DPPH˙-scavenging rates of the hydroquinones results from the remarkable positive shift of the one-electron reduction potential (Ered) of DPPH˙ in the presence of Al(3+). These results demonstrate that Al(3+), a strong Lewis acid, can act as a radical-scavenging promoter by stabilising the one-electron reduced species of the radical, although Al(3+) is reported not only to act as a pro-oxidant but also to strongly interact with biomolecules, showing toxicities.

Analysis of redox states of protic and aprotic solutions irradiated by low linear energy transfer carbon-ion beams using a 2,2-diphenyl-1-picrylhydrazyl radical

The redox states of protic and aprotic solutions were evaluated after carbon-ion irradiation.

Role of Mitochondrial Reactive Oxygen Species in the Activation of Cellular Signals, Molecules, and Function

Mitochondria are a major source of intracellular energy and reactive oxygen species in cells, but are also increasingly being recognized as a controller of cell death. Here, we review evidence of signal transduction control by mitochondrial superoxide generation via the nuclear factor-κB (NF-κB) and GATA signaling pathways. We have also reviewed the effects of ROS on the activation of MMP and HIF. There is significant evidence to support the hypothesis that mitochondrial superoxide can initiate signaling pathways following transport into the cytosol. In this study, we provide evidence of TATA signal transductions by mitochondrial superoxide. Oxidative phosphorylation via the electron transfer chain, glycolysis, and generation of superoxide from mitochondria could be important factors in regulating signal transduction, cellular homeostasis, and cell death.