Bio-Chemoinformatics-Driven Analysis of nsp7 and nsp8 Mutations and Their Effects on Viral Replication Protein Complex Stability

The nonstructural proteins 7 and 8 (nsp7 and nsp8) of SARS-CoV-2 are highly important proteins involved in the RNA-dependent polymerase (RdRp) protein replication complex. In this study, we analyzed the global mutation of nsp7 and nsp8 in 2022 and 2023 and analyzed the effects of mutation on the viral replication protein complex using bio-chemoinformatics. Frequently occurring variants are found to be single amino acid mutations for both nsp7 and nsp8. The most frequently occurring mutations for nsp7 which include L56F, L71F, S25L, M3I, D77N, V33I and T83I are predicted to cause destabilizing effects, whereas those in nsp8 are predicted to cause stabilizing effects, with the threonine to isoleucine mutation (T89I, T145I, T123I, T148I, T187I) being a frequent mutation. A conserved domain database analysis generated critical interaction residues for nsp7 (Lys-7, His-36 and Asn-37) and nsp8 (Lys-58, Pro-183 and Arg-190), which, according to thermodynamic calculations, are prone to destabilization. Trp-29, Phe-49 of nsp7 and Trp-154, Tyr-135 and Phe-15 of nsp8 cause greater destabilizing effects to the protein complex based on a computational alanine scan suggesting them as possible new target sites. This study provides an intensive analysis of the mutations of nsp7 and nsp8 and their possible implications for viral complex stability.

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.

Protocol for screening cellular outputs activated by optogenetically controlled temporal PI3K signaling activation patterns

PI3K signaling elicits distinct outputs in response to different patterns of extracellular stimulation. Here, we present a protocol for screening cellular outputs activated by optogenetically controlled temporal PI3K signaling activation patterns in 96-well plates. We describe steps for establishing PPAP2-stable cells, probe expression, and blue light irradiation. We then detail procedures for analysis of translation activity. This protocol can be applied for purposes, such as examining the effect of PI3K signaling on the efficacy of anticancer drugs. For complete details on the use and execution of this protocol, please refer to Ueda et al. (2022).1.

Split Luciferase-Fragment Reconstitution for Unveiling RNA Localization and Dynamics in Live Cells

The intracellular distribution and dynamics of RNAs play pivotal roles in various physiological phenomena. The ability to monitor the amount and localization of endogenous RNAs in living cells allows for elucidating the mechanisms of various intracellular events. Protein-based fluorescent RNA probes are now widely used to visualize and analyze RNAs in living cells. However, continuously monitoring the temporal changes in RNA localization and dynamics in living cells is challenging. In this study, we developed a bioluminescent probe for spatiotemporal monitoring of RNAs in living cells by using a split-luciferase reconstitution technique. The probe consists of split fragments of a bioluminescent protein, NanoLuc, connected with RNA-binding protein domains generated from a custom-made mutation of a PUM-HD. The probe showed rapid luminescence intensity changes in response to an increase or decrease in the amount of a target RNA in vitro. In live-cell imaging, temporal alteration of the intracellular distribution of endogenous β-actin mRNA was visualized in response to extracellular stimulation. Furthermore, the application of the probe to the visualization of the specific localization of β-actin mRNA in primary hippocampal neurons was conducted. These results demonstrate the capability of the bioluminescent RNA probe to monitor the changes in localization, dynamics, and the amount of target RNA in living cells.

Lactate biosensors for spectrally and spatially multiplexed fluorescence imaging

L-Lactate is increasingly appreciated as a key metabolite and signaling molecule in mammals. However, investigations of the inter- and intra-cellular dynamics of L-lactate are currently hampered by the limited selection and performance of L-lactate-specific genetically encoded biosensors. Here we now report a spectrally and functionally orthogonal pair of high-performance genetically encoded biosensors: a green fluorescent extracellular L-lactate biosensor, designated eLACCO2.1, and a red fluorescent intracellular L-lactate biosensor, designated R-iLACCO1. eLACCO2.1 exhibits excellent membrane localization and robust fluorescence response. To the best of our knowledge, R-iLACCO1 and its affinity variants exhibit larger fluorescence responses than any previously reported intracellular L-lactate biosensor. We demonstrate spectrally and spatially multiplexed imaging of L-lactate dynamics by coexpression of eLACCO2.1 and R-iLACCO1 in cultured cells, and in vivo imaging of extracellular and intracellular L-lactate dynamics in mice.

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.

Class 3 PI3K coactivates the circadian clock to promote rhythmic de novo purine synthesis

Metabolic demands fluctuate rhythmically and rely on coordination between the circadian clock and nutrient-sensing signalling pathways, yet mechanisms of their interaction remain not fully understood. Surprisingly, we find that class 3 phosphatidylinositol-3-kinase (PI3K), known best for its essential role as a lipid kinase in endocytosis and lysosomal degradation by autophagy, has an overlooked nuclear function in gene transcription as a coactivator of the heterodimeric transcription factor and circadian driver Bmal1-Clock. Canonical pro-catabolic functions of class 3 PI3K in trafficking rely on the indispensable complex between the lipid kinase Vps34 and regulatory subunit Vps15. We demonstrate that although both subunits of class 3 PI3K interact with RNA polymerase II and co-localize with active transcription sites, exclusive loss of Vps15 in cells blunts the transcriptional activity of Bmal1-Clock. Thus, we establish non-redundancy between nuclear Vps34 and Vps15, reflected by the persistent nuclear pool of Vps15 in Vps34-depleted cells and the ability of Vps15 to coactivate Bmal1-Clock independently of its complex with Vps34. In physiology we find that Vps15 is required for metabolic rhythmicity in liver and, unexpectedly, it promotes pro-anabolic de novo purine nucleotide synthesis. We show that Vps15 activates the transcription of Ppat, a key enzyme for the production of inosine monophosphate, a central metabolic intermediate for purine synthesis. Finally, we demonstrate that in fasting, which represses clock transcriptional activity, Vps15 levels are decreased on the promoters of Bmal1 targets, Nr1d1 and Ppat. Our findings open avenues for establishing the complexity for nuclear class 3 PI3K signalling for temporal regulation of energy homeostasis.

Akaike's Information Criterion for Stoichiometry Inference of Supramolecular Complexes

"How do we decide the stoichiometry of host-guest complexes?" This question has long been answered by the Job plot since its first report in 1928. However, as the Job plot was claimed to be misleading in 2016, the question became an open question again and called for renewed investigations. An information-theoretic approach, called Akaike's information criterion, is introduced in this study to select the best model of host-guest complexes, which can rank the models with weight of evidence. A few test cases with unique cylindrical hosts were examined to demonstrate the applicability of the information-theoretic method. Consequently, reasonable views over the thermodynamic behaviors of dumbbell-and-cylinder complexes were obtained. Akaike's information criterion can be a useful and superior alternative to statistical null hypothesis testing, which was proposed as a remedy in place of the Job plot.

Optogenetic decoding of Akt2-regulated metabolic signaling pathways in skeletal muscle cells using transomics analysis

Insulin regulates various cellular metabolic processes by activating specific isoforms of the Akt family of kinases. Here, we elucidated metabolic pathways that are regulated in an Akt2-dependent manner. We constructed a transomics network by quantifying phosphorylated Akt substrates, metabolites, and transcripts in C2C12 skeletal muscle cells with acute, optogenetically induced activation of Akt2. We found that Akt2-specific activation predominantly affected Akt substrate phosphorylation and metabolite regulation rather than transcript regulation. The transomics network revealed that Akt2 regulated the lower glycolysis pathway and nucleotide metabolism and cooperated with Akt2-independent signaling to promote the rate-limiting steps in these processes, such as the first step of glycolysis, glucose uptake, and the activation of the pyrimidine metabolic enzyme CAD. Together, our findings reveal the mechanism of Akt2-dependent metabolic pathway regulation, paving the way for Akt2-targeting therapeutics in diabetes and metabolic disorders.

Imaging and Manipulation of Plasma Membrane Fatty Acid Clusters Using TOF-SIMS Combined Optogenetics

The plasma membrane (PM) serves multiple functions to support cell activities with its heterogeneous molecular distribution. Fatty acids (FAs) are hydrophobic components of the PM whose saturation and length determine the membrane's physical properties. The FA distribution contributes to the PM's lateral heterogeneity. However, the distribution of PM FAs is poorly understood. Here, we proposed the FA cluster hypothesis, which suggested that FAs on the PM exist as clusters. By the optogenetic tool translocating the endoplasmic reticulum (ER), we were able to manipulate the distribution of PM FAs. We used time-of-flight combined secondary ion mass spectrometry (TOF-SIMS) to image PM FAs and discovered that PM FAs were presented and distributed as clusters and are also manipulated as clusters. We also found the existence of multi-FA clusters formed by the colocalization of more than one FA. Our optogenetic tool also decreased the clustering degree of FA clusters and the formation probability of multi-FA clusters. This research opens up new avenues and perspectives to study PM heterogeneity from an FA perspective. This research also suggests a possible treatment for diseases caused by PM lipid aggregation and furnished a convenient tool for therapeutic development.

Mechanistic insights into cancer drug resistance through optogenetic PI3K signaling hyperactivation

Hyperactivation of phosphatidylinositol 3-kinase (PI3K) signaling is a prominent feature in cancer cells. However, the mechanism underlying malignant behaviors in the state remains unknown. Here, we describe a mechanism of cancer drug resistance through the protein synthesis pathway, downstream of PI3K signaling. An optogenetic tool (named PPAP2) controlling PI3K signaling was developed. Melanoma cells stably expressing PPAP2 (A375-PPAP2) acquired resistance to a cancer drug in the hyperactivation state. Proteome analyses revealed that expression of the antiapoptotic factor tumor necrosis factor alpha-induced protein 8 (TNFAIP8) was upregulated. TNFAIP8 upregulation was mediated by protein translation from preexisting mRNA. These results suggest that cancer cells escape death via upregulation of TNFAIP8 expression from preexisting mRNA even though alkylating cancer drugs damage DNA.

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

N-Heterocyclic carbene-based C-centered Au(I)-Ag(I) clusters with intense phosphorescence and organelle-selective translocation in cells

Photoluminescent gold clusters are functionally variable chemical modules by ligand design. Chemical modification of protective ligands and introduction of different metals into the gold clusters lead to discover unique chemical and physical properties based on their significantly perturbed electronic structures. Here we report the synthesis of carbon-centered Au(I)-Ag(I) clusters with high phosphorescence quantum yields using N-heterocyclic carbene ligands. Specifically, a heterometallic cluster [(C)(Au^I-L)₆Ag^I₂]⁴⁺, where L denotes benzimidazolylidene-based carbene ligands featuring N-pyridyl substituents, shows a significantly high phosphorescence quantum yield (Φ = 0.88). Theoretical calculations suggest that the carbene ligands accelerate the radiative decay by affecting the spin-orbit coupling, and the benzimidazolylidene ligands further suppress the non-radiative pathway. Furthermore, these clusters with carbene ligands are taken up into cells, emit phosphorescence and translocate to a particular organelle. Such well-defined, highly phosphorescent C-centered Au(I)-Ag(I) clusters will enable ligand-specific, organelle-selective phosphorescence imaging and dynamic analysis of molecular distribution and translocation pathways in cells.

Photoluminescent gold clusters have unique chemical and physical properties based on their perturbed electronic structures. Here, the authors report the synthesis of carbon-centered Au(I)-Ag(I) clusters with high phosphorescence quantum yields using N-heterocyclic carbene ligands.

Increased spine PIP3 is sequestered from dendritic shafts

Phosphatidylinositol 3,4,5-trisphosphate (PIP3) is a lipid second messenger that is crucial for the synaptic plasticity underlying learning and memory in pyramidal neurons in the brain. Our previous study uncovered PIP3 enrichment in the dendritic spines of hippocampal pyramidal neurons in the static state using a fluorescence lifetime-based PIP3 probe. However, the extent to which PIP3 enrichment is preserved in different states has not been fully investigated. Here, we revealed that PIP3 accumulation in dendritic spines is strictly controlled even in an active state in which PIP3 is increased by glutamate stimulation and high potassium-induced membrane depolarization. Time-course PIP3 analysis clarified the gradual PIP3 accumulation in dendritic spines over days during neuronal development. Collectively, these results deepen our understanding of PIP3 dynamics in dendritic spines, and the dysregulation of the PIP3 gradient between dendritic spines and shafts could cause neuronal diseases and mental disorders, such as autism spectrum disorder.

Castanospermine suppresses CD44 ectodomain cleavage as revealed by transmembrane bioluminescent sensors

Cluster of differentiation 44 (CD44) is a single-pass transmembrane glycoprotein that is a widely distributed cell-surface adhesion molecule. CD44 undergoes ectodomain cleavage by membrane-associated metalloproteinases in breast cancer cells. Cleavage plays a critical role in cancer cell migration by mediating the interaction between CD44 and the extracellular matrix. To explore inhibitors of CD44 ectodomain cleavage, we developed two bioluminescent sensors for the detection of CD44 ectodomain cleavage. The sensors were designed as two-transmembrane proteins with split-luciferase fragments, one of which was cyclized by protein trans-splicing of a DnaE intein. These two sensors emit light by the cyclization or the spontaneous complementation of the luciferase fragments. The luminescence intensities decreased by cleavage of the ectodomain in breast cancer cells. The sensors revealed that castanospermine, an α-glucosidase inhibitor, suppressed the ectodomain cleavage of endogenous CD44 in breast cancer cells. Castanospermine also inhibited breast cancer cell invasion. Thus, the sensors are beneficial tools for evaluating the effects of different inhibitors.

A Series of Furimazine Derivatives for Sustained Live-Cell Bioluminescence Imaging and Application to the Monitoring of Myogenesis at the Single-Cell Level

Bioluminescence (BL) imaging, which utilizes light emitted through the enzymatic reaction of luciferase oxidizing its substrate luciferin, enables sensitive and noninvasive monitoring of life phenomena. Herein, we developed a series of caged furimazine (FMZ) derivatives by introducing a protective group at the C-3 position and a hydroxy group at the C-6 phenyl ring to realize long-term live-cell BL imaging based on the NanoLuc (NLuc)/NanoKAZ (NKAZ)-FMZ system. The membrane permeability and cytotoxicity of the substrates were evaluated and related to their hydrophobicity. Among the series, the derivative with the bulkiest protective group (adamantanecarbonyl group) and a hydroxy substituent (named Ad-FMZ-OH) showed significantly prolonged and constant BL signal in cells expressing NLuc compared to the native FMZ substrate. This derivative enabled continuous BL imaging at the single-cell level for 24 h. Furthermore, we applied Ad-FMZ-OH to BL imaging of myocyte fusion and succeeded in the consecutive and sensitive monitoring at a single-cell level over a day. In summary, NLuc/NKAZ-caged FMZ derivatives have the potential to be applied to live-cell BL imaging of various life phenomena that require long-term observation.

Discovery of a Phase-Separating Small Molecule That Selectively Sequesters Tubulin in Cells

Phase-separated membraneless organelles or biomolecular condensates play diverse functions in cells, however recapturing their characteristics using small organic molecules has been a challenge. In the present study, cell-lysate-based screening of 843 self-assembling small molecules led to the discovery of a simple organic molecule, named huezole, that forms liquid droplets to selectively sequester tubulin. Remarkably, this small molecule enters cultured human cells and prevents cell mitosis by forming tubulin-concentrating condensates in cells. The present study demonstrates the feasibility of producing a synthetic condensate out of non-peptidic small molecules for exogenous control of cellular processes. The modular structure of huezole provides a framework for designing a class of organelle-emulating small molecules.

A non-peptidic small molecule, R-huezole, phase separates to selectively sequester tubulin proteins to control the cell cycle. Its modular structure provides a framework for designing bioactive molecules to mimic membraneless organelles in cells.

Recent advances of vibrational spectroscopy and chemometrics for forensic biological analysis

Biological materials found at a crime scene are crucially important evidence for forensic investigation because they provide contextual information about a crime and can be linked to the donor-individuals through combination with DNA analysis. Applications of vibrational spectroscopy to forensic biological analysis have been emerging because of its advantageous characteristics such as the non-destructivity, rapid measurement, and quantitative evaluation, compared to most current methods based on histological observation or biochemical techniques. This review presents an overview of recent developments in vibrational spectroscopy for forensic biological analysis. We also emphasize chemometric techniques, which can elicit reliable and advanced analytical outputs from highly complex spectral data from forensic biological materials. The analytical subjects addressed herein include body fluids, hair, soft tissue, bones, and bioagents. Promising applications for various analytical purposes in forensic biology are presented. Simultaneously, future avenues of study requiring further investigation are discussed.

Poly(ADP-ribose) Polymerase (PARP) is Critically Involved in Liver Ischemia/reperfusion-injury

BACKGROUND

Poly(ADP-ribose) polymerase (PARP) is a DNA-repairing enzyme activated by extreme genomic stress, and therefore is potently activated in the remnant liver suffering from ischemia after surgical resection. However, the impact of PARP on post-ischemic liver injury has not been elucidated yet.

MATERIALS AND METHODS

We investigated the impact of PARP on murine hepatocyte/liver injury induced by hypoxia/ischemia, respectively.

RESULTS

PJ34, a specific inhibitor of PARP, markedly protected against hypoxia/reoxygenation (H/R)-induced cell death, though z-VAD-fmk, a pan-caspase inhibitor similarly showed the protective effect. PJ34 did not affect H/R-induced caspase activity or caspase-mediated cell death. z-VAD-fmk also did not affect the production of PAR (i.e., PARP activity). Therefore, PARP- and caspase-mediated cell death occurred in a mechanism independent of each other in H/R. H/R immediately induced activation of PARP and cell death afterwards, both of which were suppressed by PJ34 or Trolox, an antioxidant. This suggests that H/R-induced cell death occurred redox-dependently through PARP activation. H/R and OS induced nuclear translocation of apoptosis inducing factor (AIF, a marker of parthanatos) and RIP1-RIP3 interaction (a marker of necroptosis), both of which were suppressed by PJ34. H/R induced PARP-mediated parthanatos and necroptosis redox-dependently. In mouse experiments, PJ34 significantly reduced serum levels of AST, ALT & LDH and areas of hepatic necrosis after liver ischemia/reperfusion, similar to z-VAD-fmk or Trolox.

CONCLUSION

PARP, activated by ischemic damage and/or oxidative stress, may play a critical role in post-ischemic liver injury by inducing programmed necrosis (parthanatos and necroptosis). PARP inhibition may be one of the promising strategies against post-ischemic liver injury.

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.

Long-term single cell bioluminescence imaging with C-3 position protected coelenterazine analogues

Bioluminescence is a powerful imaging modality for monitoring biological phenomena both in vitro and in vivo. Bioluminescence imagin (BLI) is becoming a seamless imaging technology covering the range from cells to organs of small animals. Long-term imaging at the single cell level would lead to a true understanding of the dynamics of life phenomena. This work presents a long-term single cell bioluminescence imaging technology accomplished with C-3 position protected furimazines (FMZs), a CTZ analogues, which generate intense blue emission when paired with a highly stable engineered luciferase, Nanoluc. Four types of FMZs protected at the C-3 position have been synthesized. The type and steric bulkiness of the protection group strongly contributed to storage stability and the kinetics of the bioluminescence reactions of the analogues in human living cells. In particular, two developed FMZ analogues resulted in significantly longer bioluminescence emission with higher S/N ratio than FMZ at single cell level. Long-term bioluminescence single cell imaging technology with the developed FMZ analogues will lead to seamless imaging in the range from cells to organs of small animals.

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.

Synergetic Roles of Formyl Peptide Receptor 1 Oligomerization in Ligand-Induced Signal Transduction

G protein-coupled receptors (GPCRs) transduce extracellular signals into cells by interacting with G proteins and arrestins. Emerging evidence suggests that GPCRs on the plasma membrane are in a dynamic equilibrium among monomers, dimers, and larger oligomers. Nevertheless, the role of the oligomer formation in the GPCR signal transduction remains unclear. Using multicolor single-molecule live-cell imaging, we show a dynamic interconversion between small and large oligomer states of a chemoattractant GPCR, Formyl Peptide Receptor 1 (FPR1), and its binding affinity with G protein. Full agonist stimulation increased a fraction of large FPR1 oligomers, which allowed for prolonged FPR1-G protein interaction. The G protein interaction with FPR1 was most stabilized at the full agonist-bound large FPR1 oligomers. Based on these results, we propose that G protein-mediated signal transduction may be regulated synergistically by the ligand-binding and FPR1 oligomerization. Cooperative signal control induced by receptor oligomerization is anticipated as a target for drug discovery.

Advanced Bioluminescence System for In Vivo Imaging with Brighter and Red-Shifted Light Emission

In vivo bioluminescence imaging (BLI), which is based on luminescence emitted by the luciferase-luciferin reaction, has enabled continuous monitoring of various biochemical processes in living animals. Bright luminescence with a high signal-to-background ratio, ideally red or near-infrared light as the emission maximum, is necessary for in vivo animal experiments. Various attempts have been undertaken to achieve this goal, including genetic engineering of luciferase, chemical modulation of luciferin, and utilization of bioluminescence resonance energy transfer (BRET). In this review, we overview a recent advance in the development of a bioluminescence system for in vivo BLI. We also specifically examine the improvement in bioluminescence intensity by mutagenic or chemical modulation on several beetle and marine luciferase bioluminescence systems. We further describe that intramolecular BRET enhances luminescence emission, with recent attempts for the development of red-shifted bioluminescence system, showing great potency in in vivo BLI. Perspectives for future improvement of bioluminescence systems are discussed.

Fluorescent H2 Receptor Squaramide-Type Antagonists: Synthesis, Characterization, and Applications

Fluorescence labeled ligands have been gaining importance as molecular tools, enabling receptor-ligand-binding studies by various fluorescence-based techniques. Aiming at red-emitting fluorescent ligands for the hH₂R, a series of squaramides labeled with pyridinium or cyanine fluorophores (19-27) was synthesized and characterized. The highest hH₂R affinities in radioligand competition binding assays were obtained in the case of pyridinium labeled antagonists 19-21 (pK _i: 7.71-7.76) and cyanine labeled antagonists 23 and 25 (pK _i: 7.67, 7.11). These fluorescent ligands proved to be useful tools for binding studies (saturation and competition binding as well as kinetic experiments), using confocal microscopy, flow cytometry, and high content imaging. Saturation binding experiments revealed pK _d values comparable to the pK _i values. The fluorescent probes 21, 23, and 25 could be used to localize H₂ receptors in HEK cells and to determine the binding affinities of unlabeled compounds.

Parallelized shifted-excitation Raman difference spectroscopy for fluorescence rejection in a temporary varying system

A fluorescence background is one of the common interference factors of the Raman spectroscopic analysis in the biology field. Shifted-excitation Raman difference spectroscopy (SERDS), in which a slow (typically 1 Hz) modulation to excitation wavelength is coupled with a sequential acquisition of alternating shifted-excitation spectra, has been used to separate Raman scattering from excitation-shift insensitive background. This sequential method is susceptible to spectral change and thus is limited only to stable samples. We incorporated a fast laser modulation (200 Hz) and a mechanical streak camera into SERDS to effectively parallelize the SERDS measurement in a single exposure. The developed system expands the scope of SERDS to include temporary varying system. The proof of concept is demonstrated using highly fluorescent samples, including living algae. Quantitative performance in fluorescence rejection and the robustness of the method to the dynamic spectral change during the measurement are manifested.

Enhanced bioluminescent sensor for longitudinal detection of CREB activation in living cells

Cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) is associated with memory formation and controls cell survival and proliferation via regulation of downstream gene expression in tumorigenesis. As a transcription factor, CREB binds to cAMP response elements. Phosphorylation of CREB triggers transcriptional activation of CREB downstream genes following the interaction of the kinase-inducible domain (KID) of CREB with the KID interaction domain (KIX) of CREB-binding protein. Nevertheless, because of the lack of single-cell analytical techniques, little is known about spatiotemporal regulation of CREB phosphorylation. To analyze CREB activation in single living cells, we developed genetically encoded bioluminescent sensors using luciferase-fragment complementation: the sensors are designed based on KID-KIX interaction with a single-molecule format. The luminescence intensity of the sensor, designated as CREX (a sensor of CREB activation based on KID(CREB)-KIX interaction), increased by phosphorylation of CREB. Moreover, the luminescence intensity of CREX was sufficient to detect CREB activation in live-cell bioluminescence imaging for single-cell analysis because of the higher sensitivity. CREX sensor is expected to contribute to elucidation of the spatiotemporal regulation of CREB phosphorylation by applying single-cell analysis.

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.

Photocleavable Cadherin Inhibits Cell-to-Cell Mechanotransduction by Light

Precise integration of individual cell behaviors is indispensable for collective tissue morphogenesis and maintenance of tissue integrity. Organized multicellular behavior is achieved via mechanical coupling of individual cellular contractility, mediated by cell adhesion molecules at the cell-cell interface. Conventionally, gene depletion or laser microsurgery has been used for functional analysis of intercellular mechanotransduction. Nevertheless, these methods are insufficient to investigate either the spatiotemporal dynamics or the biomolecular contribution in cell-cell mechanical coupling within collective multicellular behaviors. Herein, we present our effort in adaption of PhoCl for attenuation of cell-to-cell tension transmission mediated by E-cadherin. To release intercellular contractile tension applied on E-cadherin molecules with external light, a genetically encoded photocleavable module called PhoCl was inserted into the intracellular domain of E-cadherin, thereby creating photocleavable cadherin (PC-cadherin). In response to light illumination, the PC-cadherin cleaved into two fragments inside cells, resulting in attenuating mechanotransduction at intercellular junctions in living epithelial cells. Light-induced perturbation of the intercellular tension balance with surrounding cells changed the cell shape in an epithelial cell sheet. The method is expected to enable optical manipulation of force-mediated cell-to-cell communications in various multicellular behaviors, which contributes to a deeper understanding of embryogenesis and oncogenesis.

Comprehensive modeling of bloodstain aging by multivariate Raman spectral resolution with kinetics

Blood, as a cardinal biological system, is a challenging target for biochemical characterization because of sample complexity and a lack of analytical approaches. To reveal and evaluate aging process of blood compositions is an unexplored issue in forensic analysis, which is useful to elucidate the details of a crime. Here we demonstrate a spectral deconvolution model of near-infrared Raman spectra of bloodstain to comprehensively describe the aging process based on the chemical mechanism, particularly the kinetics. The bloodstain spectra monitored over several months at different temperatures are decomposed into significant spectral components by multivariate calculation. The kinetic schemes of the spectral components are explored and subsequently incorporated into the developed algorithm for the optimal spectral resolution. Consequently, the index of bloodstain aging is proposed, which can be used under different experimental conditions. This work provides a novel perspective on the chemical mechanisms in bloodstain aging and facilitates forensic applications.

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.

[3H]UR-DEBa176: A 2,4-Diaminopyrimidine-Type Radioligand Enabling Binding Studies at the Human, Mouse, and Rat Histamine H4 Receptors

Differences in sequence homology between human (h), mouse (m), and rat (r) histamine H₄ receptors (H₄R) cause discrepancies regarding affinities, potencies, and/or efficacies of ligands and therefore compromise translational animal models and the applicability of radioligands. Aiming at a radioligand enabling robust and comparative binding studies at the h/m/rH₄Rs, 2,4-diaminopyrimidines were synthesized and pharmacologically investigated. The most notable compounds identified were two (partial) agonists with comparable potencies at the h/m/rH₄Rs: UR-DEBa148 (N-neopentyl-4-(1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridin-5-yl)pyrimidin-2-amine bis(2,2,2-trifluoroacetate), 43), the most potent [pEC₅₀ (reporter gene assay) = 9.9/9.6/10.3] compound in the series being slightly G-protein biased and UR-DEBa176 [(R)-4-[3-(dimethylamino)pyrrolidin-1-yl]-N-neopentylpyrimidin-2-amine bis(2,2,2-trifluoroacetate), 46, pEC₅₀ (reporter gene assay) = 8.7/9.0/9.2], a potential "cold" form of a tritiated H₄R ligand. After radiolabeling, binding studies with [³H]UR-DEBa176 ([³H]46) at the h/m/rH₄Rs revealed comparable K_d values (41/17/22 nM), low nonspecific binding (11-17%, ∼K_d), and fast associations/dissociations (25-30 min) and disclosed [³H]UR-DEBa176 as useful molecular tool to determine h/m/rH₄R binding affinities for H₄R ligands.