Temporal-Focusing Multiphoton Excitation Single-Molecule Localization Microscopy Using Spontaneously Blinking Fluorophores

Single-molecule localization microscopy (SMLM) based on temporal-focusing multiphoton excitation (TFMPE) and single-wavelength excitation is used to visualize the three-dimensional (3D) distribution of spontaneously blinking fluorophore-labeled subcellular structures in a thick specimen with a nanoscale-level spatial resolution. To eliminate the photobleaching effect of unlocalized molecules in out-of-focus regions for improving the utilization rate of the photon budget in 3D SMLM imaging, SMLM with single-wavelength TFMPE achieves wide-field and axially confined two-photon excitation (TPE) of spontaneously blinking fluorophores. TPE spectral measurement of blinking fluorophores is then conducted through TFMPE imaging at a tunable excitation wavelength, yielding the optimal TPE wavelength for increasing the number of detected photons from a single blinking event during SMLM. Subsequently, the TPE fluorescence of blinking fluorophores is recorded to obtain a two-dimensional TFMPE-SMLM image of the microtubules in cancer cells with a localization precision of 18 ± 6 nm and an overall imaging resolution of approximately 51 nm, which is estimated based on the contribution of Nyquist resolution and localization precision. Combined with astigmatic imaging, the system is capable of 3D TFMPE-SMLM imaging of brain tissue section of a 5XFAD transgenic mouse with the pathological features of Alzheimer's disease, revealing the distribution of neurotoxic amyloid-beta peptide deposits.

Crucial Roles of Leaving Group and Open-Shell Cation in Photoreaction of (Coumarin-4-yl)methyl Derivatives

Photoreactions of (coumarin-4-yl)methyl derivatives have been extensively studied in many fields of chemistry, including organic synthesis and photoinduced drug delivery systems. The identification of the reaction intermediates involved in the photoreactions is crucial not only for elucidating the reaction mechanism but also for the application of the photoreactions. In this study, the photoreactions of 7-diethylamino(coumarin-4-yl)methyl thioester 1a [-SC(O)CH3], thionoester 1b [-OC(S)CH3], and ester 1c [-OC(O)CH3] were investigated to clarify the intermediary species and their chemical behavior. While a radical pair [i.e., 7-diethylamino(coumarin-4-yl)methyl radical and CH3C(O)S•] plays an important role in the photoreactions of 1a and 1b, an ion pair [i.e., 7-diethylamino(coumarin-4-yl)methyl cation, and CH3CO2-] was the key in the photoreaction of 1c. 18O-isotope-labeling of 1c revealed a negligible recombination process within the ion pair. The unprecedented observation was rationalized by the open-shell character of the 7-diethylamino(coumarin-4-yl)methyl cation, whose formation was confirmed through product analysis and transient absorption spectroscopy.

Limb-Clasping Response in NMDA Receptor Palmitoylation-Deficient Mice

Proper regulation of N-methyl-D-aspartate-type glutamate receptor (NMDA receptor) expression is responsible for excitatory synaptic functions in the mammalian brain. NMDA receptor dysfunction can cause various neuropsychiatric disorders and neurodegenerative diseases. Posttranslational protein S-palmitoylation, the covalent attachment of palmitic acid to intracellular cysteine residues via thioester bonds, occurs in the carboxyl terminus of GluN2B, which is the major regulatory NMDA receptor subunit. Mutations of three palmitoylatable cysteine residues in the membrane-proximal cluster of GluN2B to non-palmitoylatable serine (3CS) lead to the dephosphorylation of GluN2B Tyr1472 in the hippocampus and cerebral cortex, inducing a reduction in the surface expression of GluN2B-containig NMDA receptors. Furthermore, adult GluN2B 3CS homozygous mice demonstrated a definite clasping response without abnormalities in the gross brain structure, other neurological reflexes, or expression levels of synaptic proteins in the cerebrum. This behavioral disorder, observed in the GluN2B 3CS knock-in mice, indicated that complex higher brain functions are coordinated through the palmitoylation-dependent regulation of NMDA receptors in excitatory synapses.

Development of a Two-Photon-Responsive Chromophore, 2-(p-Aminophenyl)-5,6-dimethoxy-1-(hydroxyinden-3-yl)methyl Derivative, as a Photoremovable Protecting Group

Photoremovable protecting groups (PPGs) are powerful tools that are widely used to investigate biological events in cells. An important requirement for PPGs is the efficient release of bioactive molecules by using visible to near-infrared light in the biological window (650-1350 nm). In this study, we report a new two-photon (2P)-responsive PPG, 2-(p-aminophenyl)-5,6-dimethoxy-1-(hydroxyinden-3-yl)methyl, with a donor-π-donor cyclic stilbene structure. The 2P cross section was approximately 40-50 GM at ∼700 nm. The quantum yield of the uncaging process of caged benzoate was greater than 0.7, demonstrating that the 2P uncaging efficiency was approximately 30 GM at around 700 nm. This newly developed 2P-responsive chromophore can be used in future biological experiments. The mechanism of the photo-uncaging reaction via the carbocation intermediate was elucidated using transient absorption spectroscopy and product analysis.

Sequential C-F Bond Transformation of the Difluoromethylene Unit in Perfluoroalkyl Groups: A Combination of Fine-Tuned Phenothiazine Photoredox Catalyst and Lewis Acid

A sequential process via photoredox catalysis and Lewis acid mediation for C-F bond transformation of the CF2 unit in perfluoroalkyl groups has been achieved to transform perfluoroalkylarenes into complex fluoroalkylated compounds. A phenothiazine-based photocatalyst promotes the defluoroaminoxylation of perfluoroalkylarenes with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) under visible light irradiation, affording the corresponding aminoxylated products. These products undergo a further defluorinative transformation with various organosilicon reagents mediated by AlCl3 to provide highly functionalized perfluoroalkyl alcohols. Our novel phenothiazine catalyst works efficiently in the defluoroaminoxylation. Transient absorption spectroscopy revealed that the catalyst regeneration step is crucial for the photocatalytic aminoxylation.

Bidirectional Neuronal Actuation by Uncaging with Violet and Green Light

We have developed a photochemical protecting group that enables wavelength selective uncaging using green versus violet light. Change of the exocyclic oxygen of the laser dye coumarin-102 to sulfur, gave thio-coumarin-102, a new chromophore with an absorption ratio at 503/402 nm of 37. Photolysis of thio-coumarin-102 caged γ-aminobutyric acid was found to be highly wavelength selective on neurons, with normalized electrical responses >100-fold higher in the green versus violet channel. When partnered with coumarin-102 caged glutamate, we could use whole cell violet and green irradiation to fire and block neuronal action potentials with complete orthogonality. Localized irradiation of different dendritic segments, each connected to a neuronal cell body, in concert with 3-dimenional Ca2+ imaging, revealed that such inputs could function independently. Chemical signaling in living cells always involves a complex balance of multiple pathways, use of (thio)-coumarin-102 caged compounds will enable arbitrarily timed flashes of green and violet light to interrogate two independent pathways simultaneously.

Behavioral analysis of kainate receptor KO mice and the role of GluK3 subunit in anxiety

Kainate receptors (KARs) are one of the ionotropic glutamate receptors in the central nervous system (CNS) comprised of five subunits, GluK1-GluK5. There is a growing interest in the association between KARs and psychiatric disorders, and there have been several studies investigating the behavioral phenotypes of KAR deficient mice, however, the difference in the genetic background has been found to affect phenotype in multiple mouse models of human diseases. Here, we examined GluK1-5 single KO mice in a pure C57BL/6N background and identified that GluK3 KO mice specifically express anxiolytic-like behavior with an alteration in dopamine D2 receptor (D2R)-induced anxiety, and reduced D2R expression in the striatum. Biochemical studies in the mouse cortex confirmed that GluK3 subunits do not assemble with GluK4 and GluK5 subunits, that can be activated by lower concentration of agonists. Overall, we found that GluK3-containing KARs function to express anxiety, which may represent promising anti-anxiety medication targets.

Photoexcitation of (diarylmethylene)amino benziodoxolones for alkylamination of styrene derivatives with carboxylic acids

The alkylamination of alkenes using pristine carboxylic acids was achieved by the photoexcitation of (diarylmethylene)amino benziodoxolones (DABXs), which serve as both an oxidant and an aminating reagent (an iminyl radical precursor). The developed method is a simple photochemical reaction without the need for external photosensitizers and shows a broad substrate scope for aliphatic carboxylic acids leading to the formation of primary, secondary, and tertiary alkyl radicals, thus enabling the facile synthesis of various structurally complex amines. Mechanistic investigations including transient absorption spectroscopy measurements using a laser flash photolysis (LFP) method disclosed the unique photochemical reactivity of DABXs, which undergoes homolysis of their I-N bonds to give an iminyl radical and ortho-iodobenzoyloxy radical, the latter of which participates in the single-electron oxidation of carboxylates.

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.

Brain-enriched guanylate kinase-associated protein, a component of the post-synaptic density protein complexes, contributes to learning and memory

Brain-enriched guanylate kinase-associated protein (BEGAIN) is highly enriched in the post-synaptic density (PSD) fraction and was identified in our previous study as a protein associated with neuropathic pain in the spinal dorsal horn. PSD protein complexes containing N-methyl-D-aspartate receptors are known to be involved in neuropathic pain. Since these PSD proteins also participate in learning and memory, BEGAIN is also expected to play a crucial role in this behavior. To verify this, we first examined the distribution of BEGAIN in the brain. We found that BEGAIN was widely distributed in the brain and highly expressed in the dendritic regions of the hippocampus. Moreover, we found that BEGAIN was concentrated in the PSD fraction of the hippocampus. Furthermore, immunoelectron microscopy confirmed that BEGAIN was localized at the asymmetric synapses. Behavioral tests were performed using BEGAIN-knockout (KO) mice to determine the contribution of BEGAIN toward learning and memory. Spatial reference memory and reversal learning in the Barns circular maze test along with contextual fear and cued fear memory in the contextual and cued fear conditioning test were significantly impaired in BEGAIN-KO mice compared to with those in wild-type mice. Thus, this study reveals that BEGAIN is a component of the post-synaptic compartment of excitatory synapses involved in learning and memory.

Photoinduced α-Aminoalkylation of Sulfonylarenes with Alkylamines

α-Aminoalkylation of sulfonylarenes with alkylamines was found to be induced by photoirradiation. Here various types of alkylamines, such as trialkylamines, dialkylamines, N,N-dialkylanilines and N-alkylanilines as well as sulfonylarenes containing an azole, azine, heterole or benzene ring are available. The reaction proceeds through a homolytic aromatic substitution (HAS) process consisting of addition of an α-aminoalkyl radical to a sulfonylarene and elimination of the sulfonyl radical to give the α-arylalkylamine, where photoirradiation is considered to induce homolysis of sulfonylarenes leading to the generation of α-aminoalkyl radicals that make a radical chain operative.

Photochemically Induced Hydrogen Atom Transfer and Intramolecular Radical Cyclization Reactions with Oxazolones

Photochemically induced intramolecular hydrogen atom transfer in oxazolones is reported. An acetal or thioacetal function at the side chain acts as a hydrogen donor while the photochemical exited oxazolone is the acceptor. A one-step process─the electron and the proton are simultaneously transferred─is productive, while electron transfer followed by proton transfer is inefficient. Radical combination then takes place, leading to the formation of a C-C or C-N bond. The regioselectivity of the reaction is explained by the diradical/zwitterion dichotomy of radical intermediates at the singlet state. In the present case, the zwitterion structure plays a central role, and intramolecular electron transfer favors spin-orbit coupling and thus the intersystem crossing to the singlet state. The reaction of corresponding thioacetal derivatives is less efficient. In this case, photochemical electron transfer is competitive. The photoproducts resulting from C-C bond formation easily undergo stepwise thermal decarboxylation in which zwitterionic and polar transition states are involved. A computational study of this step has also been performed.

Energetically More Stable Singlet Cyclopentane-1,3-diyl Diradical with π-Single Bonding Character than the Corresponding σ-Single Bonded Compound

Carbon-carbon σ-single bonds are crucial for constructing molecules like ethane derivatives (R3C-CR3), which are composed of tetrahedral four-coordinate carbons. Molecular functions, such as light absorption or emission, originate from the π-bonds existing in ethylene derivatives (R2C═CR2). In this study, a relatively stable cyclopentane-1,3-diyl species with π-single bonding system (C-π-C) with planar four-coordinate carbons is constructed. This diradicaloid is energetically more stable than the corresponding σ-single bonding system. The π-electron single bonding system provides deeper insights into the chemical bonding and the physical properties derived from the small energy gaps between the bonding and antibonding molecular orbitals.

Very-long-chain fatty acids are crucial to neuronal polarity by providing sphingolipids to lipid rafts

Fatty acids have long been considered essential to brain development; however, the involvement of their synthesis in nervous system formation is unclear. We generate mice with knockout of GPSN2, an enzyme for synthesis of very-long-chain fatty acids (VLCFAs) and investigate the effects. Both GPSN2-/- and GPSN2+/- mice show abnormal neuronal networks as a result of impaired neuronal polarity determination. Lipidomics of GPSN2-/- embryos reveal that ceramide synthesis is specifically inhibited depending on FA length; namely, VLCFA-containing ceramide is reduced. We demonstrate that lipid rafts are highly enriched in growth cones and that GPSN2+/- neurons lose gangliosides in their membranes. Application of C24:0 ceramide, but not C16:0 ceramide or C24:0 phosphatidylcholine, to GPSN2+/- neurons rescues both neuronal polarity determination and lipid-raft density in the growth cone. Taken together, our results indicate that VLCFA synthesis contributes to physiological neuronal development in brain network formation, in particular neuronal polarity determination through the formation of lipid rafts.

An intact pituitary vasopressin system is critical for building a robust circadian clock in the suprachiasmatic nucleus

The circadian clock is a biological timekeeping system that oscillates with a circa-24-h period, reset by environmental timing cues, especially light, to the 24-h day-night cycle. In mammals, a "central" clock in the hypothalamic suprachiasmatic nucleus (SCN) synchronizes "peripheral" clocks throughout the body to regulate behavior, metabolism, and physiology. A key feature of the clock's oscillation is resistance to abrupt perturbations, but the mechanisms underlying such robustness are not well understood. Here, we probe clock robustness to unexpected photic perturbation by measuring the speed of reentrainment of the murine locomotor rhythm after an abrupt advance of the light-dark cycle. Using an intersectional genetic approach, we implicate a critical role for arginine vasopressin pathways, both central within the SCN and peripheral from the anterior pituitary.

Production of marmoset eggs and embryos from xenotransplanted ovary tissues

The common marmoset (Callithrix jacchus) has attracted attention as a valuable primate model for the analysis of human diseases. Despite the potential for primate genetic modification, however, its widespread lab usage has been limited due to the requirement for a large number of eggs. To make up for traditional oocyte retrieval methods such as hormone administration and surgical techniques, we carried out an alternative approach by utilizing ovarian tissue from deceased marmosets that had been disposed of. This ovarian tissue contains oocytes and can be used as a valuable source of follicles and oocytes. In this approach, the ovarian tissue sections were transplanted under the renal capsules of immunodeficient mice first. Subsequent steps consist of development of follicles by hormone administrations, induction of oocyte maturation and fertilization, and culture of the embryo. This method was first established with rat ovaries, then applied to marmoset ovaries, ultimately resulting in the successful acquisition of the late-stage marmoset embryos. This approach has the potential to contribute to advancements in genetic modification research and disease modeling through the use of primate models, promoting biotechnology with non-human primates and the 3Rs principle in animal experimentation.

Brn3a controls the soma localization and axonal extension patterns of developing spinal dorsal horn neurons

The spinal dorsal horn comprises heterogeneous neuronal populations, that interconnect with one another to form neural circuits modulating various types of sensory information. Decades of evidence has revealed that transcription factors expressed in each neuronal progenitor subclass play pivotal roles in the cell fate specification of spinal dorsal horn neurons. However, the development of subtypes of these neurons is not fully understood in more detail as yet and warrants the investigation of additional transcription factors. In the present study, we examined the involvement of the POU domain-containing transcription factor Brn3a in the development of spinal dorsal horn neurons. Analyses of Brn3a expression in the developing spinal dorsal horn neurons in mice demonstrated that the majority of the Brn3a-lineage neurons ceased Brn3a expression during embryonic stages (Brn3a-transient neurons), whereas a limited population of them continued to express Brn3a at high levels after E18.5 (Brn3a-persistent neurons). Loss of Brn3a disrupted the localization pattern of Brn3a-persistent neurons, indicating a critical role of this transcription factor in the development of these neurons. In contrast, Brn3a overexpression in Brn3a-transient neurons directed their localization in a manner similar to that in Brn3a-persistent neurons. Moreover, Brn3a-overexpressing neurons exhibited increased axonal extension to the ventral and ventrolateral funiculi, where the axonal tracts of Brn3a-persistent neurons reside. These results suggest that Brn3a controls the soma localization and axonal extension patterns of Brn3a-persistent spinal dorsal horn neurons.

Pathogenesis, Clinical Features, and Treatment of Patients with Myelin Oligodendrocyte Glycoprotein (MOG) Autoantibody-Associated Disorders Focusing on Optic Neuritis with Consideration of Autoantibody-Binding Sites: A Review

Although there is a substantial amount of data on the clinical characteristics, diagnostic criteria, and pathogenesis of myelin oligodendrocyte glycoprotein (MOG) autoantibody-associated disease (MOGAD), there is still uncertainty regarding the MOG protein function and the pathogenicity of anti-MOG autoantibodies in this disease. It is important to note that the disease characteristics, immunopathology, and treatment response of MOGAD patients differ from those of anti-aquaporin 4 antibody-positive neuromyelitis optica spectrum disorders (NMOSDs) and multiple sclerosis (MS). The clinical phenotypes of MOGAD are varied and can include acute disseminated encephalomyelitis, transverse myelitis, cerebral cortical encephalitis, brainstem or cerebellar symptoms, and optic neuritis. The frequency of optic neuritis suggests that the optic nerve is the most vulnerable lesion in MOGAD. During the acute stage, the optic nerve shows significant swelling with severe visual symptoms, and an MRI of the optic nerve and brain lesion tends to show an edematous appearance. These features can be alleviated with early extensive immune therapy, which may suggest that the initial attack of anti-MOG autoantibodies could target the structures on the blood-brain barrier or vessel membrane before reaching MOG protein on myelin or oligodendrocytes. To understand the pathogenesis of MOGAD, proper animal models are crucial. However, anti-MOG autoantibodies isolated from patients with MOGAD do not recognize mouse MOG efficiently. Several studies have identified two MOG epitopes that exhibit strong affinity with human anti-MOG autoantibodies, particularly those isolated from patients with the optic neuritis phenotype. Nonetheless, the relations between epitopes on MOG protein remain unclear and need to be identified in the future.

Molecular and Crystal Structure, Spectroscopy, and Photochemistry of a Dispiro Compound Bearing the Tetraoxane Pharmacophore

The molecular structure and photochemistry of dispiro[cyclohexane-1,3'-[1,2,4,5]tetraoxane-6',2''-tricyclo[3.3.1.13,7 ]decan]-4-one (TX), an antiparasitic 1,2,4,5-tetraoxane was investigated using matrix isolation IR and EPR spectroscopies, together with quantum chemical calculations undertaken at the DFT(B3LYP)/6-311++G(3df,3pd) level of theory, with and without Grimme's dispersion correction. Photolysis of the matrix-isolated TX, induced by in situ broadband (λ>235 nm) or narrowband (λ in the range 220-263 nm) irradiation, led to new bands in the infrared spectrum that could be ascribed to two distinct photoproducts, oxepane-2,5-dione, and 4-oxohomoadamantan-5-one. Our studies show that these photoproducts result from initial photoinduced cleavage of an O-O bond, with the formation of an oxygen-centered diradical that regioselectivity rearranges to a more stable (secondary carbon-centered)/(oxygen-centered) diradical, yielding the final products. Formation of the diradical species was confirmed by EPR measurements, upon photolysis of the compound at λ=266 nm, in acetonitrile ice (T=10-80 K). Single-crystal X-ray diffraction (XRD) studies demonstrated that the TX molecule adopts nearly the same conformation in the crystal and matrix-isolation conditions, revealing that the intermolecular interactions in the TX crystal are weak. This result is in keeping with observed similarities between the infrared spectrum of the crystalline material and that of matrix-isolated TX. The detailed structural, vibrational, and photochemical data reported here appear relevant to the practical uses of TX in medicinal chemistry, considering its efficient and broad parasiticidal properties.

Vasopressin expressed in hypothalamic CRF neurons causes impaired water diuresis in secondary adrenal insufficiency

Patients with secondary adrenal insufficiency can present with impaired free water excretion and hyponatremia, which is due to the enhanced secretion of vasopressin (AVP) despite increased total body water. AVP is produced in magnocellular neurons in the paraventricular nucleus of the hypothalamus (PVH) and supraoptic nucleus and in parvocellular corticotropin-releasing factor (CRF) neurons in the PVH. This study aimed to elucidate whether magnocellular AVP neurons or parvocellular CRF neurons co-expressing AVP are responsible for the pathogenesis of hyponatremia in secondary adrenal insufficiency. The number of CRF neurons expressing copeptin, an AVP gene product, was significantly higher in adrenalectomized AVP-floxed mice (AVPfl/fl) than in sham-operated controls. Adrenalectomized AVPfl/fl mice supplemented with aldosterone showed impaired water diuresis, under ad libitum access to water or after acute water loading. They became hyponatremic after acute water loading, and it was revealed under the condition that aquaporin-2 (AQP2) protein levels were increased in the kidney. Furthermore, translocation of AQP2 to the apical membrane was markedly enhanced in renal collecting duct epithelial cells. Remarkably, all these abnormalities observed in the mouse model for secondary adrenal insufficiency were ameliorated in CRF-AVP-/- mice that lacked AVP in CRF neurons. Our study demonstrates that CRF neurons in the PVH are responsible for the pathogenesis of impaired water excretion in secondary adrenal insufficiency.

Phosphorylation of phase-separated p62 bodies by ULK1 activates a redox-independent stress response

NRF2 is a transcription factor responsible for antioxidant stress responses that is usually regulated in a redox-dependent manner. p62 bodies formed by liquid-liquid phase separation contain Ser349-phosphorylated p62, which participates in the redox-independent activation of NRF2. However, the regulatory mechanism and physiological significance of p62 phosphorylation remain unclear. Here, we identify ULK1 as a kinase responsible for the phosphorylation of p62. ULK1 colocalizes with p62 bodies, directly interacting with p62. ULK1-dependent phosphorylation of p62 allows KEAP1 to be retained within p62 bodies, thus activating NRF2. p62^S351E/+ mice are phosphomimetic knock-in mice in which Ser351, corresponding to human Ser349, is replaced by Glu. These mice, but not their phosphodefective p62^S351A/S351A counterparts, exhibit NRF2 hyperactivation and growth retardation. This retardation is caused by malnutrition and dehydration due to obstruction of the esophagus and forestomach secondary to hyperkeratosis, a phenotype also observed in systemic Keap1-knockout mice. Our results expand our understanding of the physiological importance of the redox-independent NRF2 activation pathway and provide new insights into the role of phase separation in this process.

Light-Mediated Synthesis of 2-(4-Methoxyphenyl)-1-pyrroline via Intramolecular Reductive Cyclization of a Triplet Alkylnitrene

Irradiation of p-methoxyazidobutyrophenone (1) in methanol yielded 2-(4-methoxyphenyl)-1-pyrroline (2) and several other photoproducts. However, in the presence of tris(trimethylsilyl)silane (TTMSS), 2 is formed selectively. Transient absorption and ESR spectroscopy verify that the irradiation of 1 forms triplet alkylnitrene ³1N through intramolecular energy transfer from the triplet ketone (T_1K). DFT calculations indicate that ³1N abstracts H atoms from TTMSS but not methanol, which explains the selectivity. Thus, triplet alkylnitrenes can undergo selective reductive cyclization via H atom abstraction from TTMSS.

Manipulation of an electron by photoirradiation in the electron-catalyzed cross-coupling reaction

An electron has recently been shown to catalyze the cross-coupling reaction of organometallic compounds with aryl halides. In terms of green and sustainable chemistry, the electron catalysis is much more desirable than the inevitably used transition metal catalysis but a high temperature of more than 100°C is required to achieve it. Here, we disclose that visible light photoirradiation accelerates the electron-catalyzed reaction of arylzinc reagents with aryl halides with the aid of a photoredox catalysis. Photoexcitation of a photoredox catalyst and an anion radical intermediate respectively affects the supply and transfer of the electron catalyst, promoting the cross-coupling reaction to proceed at room temperature. The supply of the electron catalyst by the photoredox catalysis makes the scope of aryl halides wider.

Generation and Characterization of a Tetraradical Embedded in a Curved Cyclic Paraphenylene Unit

Unique spin-spin (magnetic) interactions, ring-size effects on ground-state spin multiplicity, and in-plane aromaticity has been found in localized 1,3-diradicals embedded in curved benzene structures such as cycloparaphenylene (CPP). In this study, we characterized the magnetic interactions in a tetraradical consisting of two localized 1,3-diradical units connected by p-quaterphenyl within a curved CPP skeleton by electron paramagnetic resonance (EPR) spectroscopy and quantum chemical calculations. Persistent triplet species with zero-field splitting parameters similar to those of a triplet 1,3-diphenylcyclopentane-1,3-diyl diradical were observed by continuous wave (CW) or pulsed X-band EPR measurements. The quintet state derived from the ferromagnetic interaction between the two triplet diradical moieties was not detected at 20 K under glassy matrix conditions. At the B3LYP/6-31G(d) level of theory, the singlet state was lower in energy than the triplet and quintet states. These findings will aid in the development of open-shell species for material science application.

Critical Role of the Presynaptic Protein CAST in Maintaining the Photoreceptor Ribbon Synapse Triad

The cytomatrix at the active zone-associated structural protein (CAST) and its homologue, named ELKS, being rich in glutamate (E), leucine (L), lysine (K), and serine (S), belong to a family of proteins that organize presynaptic active zones at nerve terminals. These proteins interact with other active zone proteins, including RIMs, Munc13s, Bassoon, and the β subunit of Ca²⁺ channels, and have various roles in neurotransmitter release. A previous study showed that depletion of CAST/ELKS in the retina causes morphological changes and functional impairment of this structure. In this study, we investigated the roles of CAST and ELKS in ectopic synapse localization. We found that the involvement of these proteins in ribbon synapse distribution is complex. Unexpectedly, CAST and ELKS, in photoreceptors or in horizontal cells, did not play a major role in ribbon synapse ectopic localization. However, depletion of CAST and ELKS in the mature retina resulted in degeneration of the photoreceptors. These findings suggest that CAST and ELKS play critical roles in maintaining neural signal transduction in the retina, but the regulation of photoreceptor triad synapse distribution is not solely dependent on their actions within photoreceptors and horizontal cells.

Excited-State Intramolecular Proton Transfer in Salicylidene-α-Hydroxy Carboxylate Derivatives: Direct Detection of the Triplet Excited State of the cis-Keto Tautomer

Excited-state intramolecular hydrogen transfer on the triplet surface of salicylideneaniline derivatives has received much less attention than the corresponding ultrafast process on the singlet surface. To enhance the understanding of this triplet reactivity, the photochemical properties of a series of salicylidene-α-hydroxy acid salts with different substituents on the phenol moiety (1-3) were characterized. UV/vis absorption and phosphorescence measurements in ethanol revealed that 1-3 exist as both enol and keto tautomers, with the enol form being predominant. Irradiation of 1 at 310 nm in ethanol glass (77 K) yielded an absorption band with a λ_max at ∼405 nm, which was assigned to the trans-keto tautomer (trans-1K). In contrast, laser flash photolysis of 1-3 in methanol or acetonitrile resulted in a transient absorption with λ_max at 440-460 nm. This transient, which decayed on the microsecond timescale and was significantly shorter lived in methanol than in acetonitrile, was assigned to the triplet excited state (T₁) of the cis-keto tautomer (cis-1K-3K) and residual absorption of trans-1K-3K by comparison with TD-DFT calculations. The assignment of the T₁ of cis-1K was further supported by quenching studies with anthracene and 2,5-dimethyl-2,4-hexadiene. Laser flash photolysis of 1 in the temperature range of 173-293 K gave an activation barrier of 6.7 kcal/mol for the decay of the T₁ of cis-1K. In contrast, the calculated activation barrier for cis-1K to undergo a 1,5-H atom shift to reform 1 was smaller, indicating that intersystem crossing of the T₁ of cis-1K is the rate-determining step in the regeneration of 1.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Neurexins in serotonergic neurons regulate neuronal survival, serotonin transmission, and complex mouse behaviors

Extensive serotonin (5-hydroxytryptamine, 5-HT) innervation throughout the brain corroborates 5-HT's modulatory role in numerous cognitive activities. Volume transmission is the major mode for 5-HT transmission but mechanisms underlying 5-HT signaling are still largely unknown. Abnormal brain 5-HT levels and function have been implicated in autism spectrum disorder (ASD). Neurexin (Nrxn) genes encode presynaptic cell adhesion molecules important for the regulation of synaptic neurotransmitter release, notably glutamatergic and GABAergic transmission. Mutations in Nrxn genes are associated with neurodevelopmental disorders including ASD. However, the role of Nrxn genes in the 5-HT system is poorly understood. Here, we generated a mouse model with all three Nrxn genes disrupted specifically in 5-HT neurons to study how Nrxns affect 5-HT transmission. Loss of Nrxns in 5-HT neurons reduced the number of serotonin neurons in the early postnatal stage, impaired 5-HT release, and decreased 5-HT release sites and serotonin transporter expression. Furthermore, 5-HT neuron-specific Nrxn knockout reduced sociability and increased depressive-like behavior. Our results highlight functional roles for Nrxns in 5-HT neurotransmission, 5-HT neuron survival, and the execution of complex behaviors.

A new beta cell-specific mitophagy reporter mouse shows that metabolic stress leads to accumulation of dysfunctional mitochondria despite increased mitophagy

AIMS/HYPOTHESIS

Mitophagy, the selective autophagy of mitochondria, is essential for maintenance of mitochondrial function. Recent studies suggested that defective mitophagy in beta cells caused diabetes. However, because of technical difficulties, the development of a convenient and reliable method to evaluate mitophagy in beta cells in vivo is needed. The aim of this study was to establish beta cell-specific mitophagy reporter mice and elucidate the role of mitophagy in beta cell function under metabolically stressed conditions induced by a high-fat diet (HFD).

METHODS

Mitophagy was assessed using newly generated conditional mitochondrial matrix targeting mitophagy reporter (CMMR) mice, in which mitophagy can be visualised specifically in beta cells in vivo using a fluorescent probe sensitive to lysosomal pH and degradation. Metabolic stress was induced in mice by exposure to the HFD for 20 weeks. The accumulation of dysfunctional mitochondria was examined by staining for functional/total mitochondria and reactive oxygen species (ROS) using specific fluorescent dyes and antibodies. To investigate the molecular mechanism underlying mitophagy in beta cells, overexpression and knockdown experiments were performed. HFD-fed mice were examined to determine whether chronic insulin treatment for 6 weeks could ameliorate mitophagy, mitochondrial function and impaired insulin secretion.

RESULTS

Exposure to the HFD increased the number of enlarged (HFD-G) islets with markedly elevated mitophagy. Mechanistically, HFD feeding induced severe hypoxia in HFD-G islets, which upregulated mitophagy through the hypoxia-inducible factor 1-ɑ (Hif-1ɑ)/BCL2 interacting protein 3 (BNIP3) axis in beta cells. However, HFD-G islets unexpectedly showed the accumulation of dysfunctional mitochondria due to excessive ROS production, suggesting an insufficient capacity of mitophagy for the degradation of dysfunctional mitochondria. Chronic administration of insulin ameliorated hypoxia and reduced ROS production and dysfunctional mitochondria, leading to decreased mitophagy and restored insulin secretion.

CONCLUSIONS/INTERPRETATION

We demonstrated that CMMR mice enabled the evaluation of mitophagy in beta cells. Our results suggested that metabolic stress induced by the HFD caused the aberrant accumulation of dysfunctional mitochondria, which overwhelmed the mitophagic capacity and was associated with defective maintenance of mitochondrial function and impaired insulin secretion.

The UFM1 system regulates ER-phagy through the ufmylation of CYB5R3

Protein modification by ubiquitin-like proteins (UBLs) amplifies limited genome information and regulates diverse cellular processes, including translation, autophagy and antiviral pathways. Ubiquitin-fold modifier 1 (UFM1) is a UBL covalently conjugated with intracellular proteins through ufmylation, a reaction analogous to ubiquitylation. Ufmylation is involved in processes such as endoplasmic reticulum (ER)-associated protein degradation, ribosome-associated protein quality control at the ER and ER-phagy. However, it remains unclear how ufmylation regulates such distinct ER-related functions. Here we identify a UFM1 substrate, NADH-cytochrome b5 reductase 3 (CYB5R3), that localizes on the ER membrane. Ufmylation of CYB5R3 depends on the E3 components UFL1 and UFBP1 on the ER, and converts CYB5R3 into its inactive form. Ufmylated CYB5R3 is recognized by UFBP1 through the UFM1-interacting motif, which plays an important role in the further uyfmylation of CYB5R3. Ufmylated CYB5R3 is degraded in lysosomes, which depends on the autophagy-related protein Atg7- and the autophagy-adaptor protein CDK5RAP3. Mutations of CYB5R3 and genes involved in the UFM1 system cause hereditary developmental disorders, and ufmylation-defective Cyb5r3 knock-in mice exhibit microcephaly. Our results indicate that CYB5R3 ufmylation induces ER-phagy, which is indispensable for brain development.

Tris(4'-Nitrobiphenyl)amine─An Octupolar Chromophore with High Two-Photon Absorption Cross-Section and Its Application for Uncaging of Calcium Ions in the Near-Infrared Region

Compounds with high two-photon absorption (2PA) performance in the near-infrared region have attracted great attention because of their application in the material and biological science. In this study, we have developed a simple and novel octupolar chromophore, tris(4'-nitrobiphenyl)amine 1, with three nitro peripheral groups attached to a triphenylamine core via biphenyl linkers. A mono-branched analogue 2 has also been prepared to investigate the effects of octupolar and dipolar systems on photophysical and 2PA behaviors. Compound 1, despite having a much simpler structure than the previous three-branched scaffolds, exhibits comparable σ₂ values, reaching 1330 GM at 730 nm and 900 GM at 820 nm in toluene. Combined with an outstanding σ₂/MW ratio (2.2 GM g^-1 mol) and a high fluorescence quantum yield (0.51), 1 displays potential as a promising two-photon (2P) probe for bioimaging. Subsequently, the ethylene glycol tetraacetic acid-substituted derivatives featuring octupolar (3 and 5) or dipolar (4 and 6) character have been synthesized and their one-photon (1P) and 2P photochemical reactions have been examined. Finally, 1P- and 2P-triggered uncaging of Ca²⁺ from these calcium chelators has been confirmed.

Effects of Arterial Stiffness on Cerebral WM Integrity in Older Adults: A Neurite Orientation Dispersion and Density Imaging and Magnetization Transfer Saturation Imaging Study

BACKGROUND AND PURPOSE

Arterial stiffness is reported to be able to cause axonal demyelination or degeneration. The present study aimed to use advanced MR imaging techniques to examine the effect of arterial stiffness on the WM microstructure among older adults.

MATERIALS AND METHODS

Arterial stiffness was measured using the cardio-ankle vascular elasticity index (CAVI). The high-CAVI (mean CAVI ≥ 9 points) and the low-CAVI groups (mean CAVI < 9 points) were created. The neuronal fiber integrity of the WM was evaluated by neurite orientation dispersion and density imaging and magnetization transfer saturation imaging. Tract-Based Spatial Statistics and the tracts-of-interest analysis were performed. Specific WM regions (corpus callosum, internal capsule, anterior thalamic radiation, corona radiata, superior longitudinal fasciculus, forceps minor, and inferior fronto-occipital fasciculus) were selected in the tracts-of-interest analysis.

RESULTS

In Tract-Based Spatial Statistics, the high-CAVI group showed a significantly lower myelin volume fraction value in the broad WM and significantly higher radial diffusivity and isotropic volume fraction values in the corpus callosum, forceps minor, inferior fronto-occipital fasciculus, internal capsule, corona radiata, and anterior thalamic radiation than the low-CAVI group. In tracts-of-interest analysis using multivariate linear regression, significant associations were found between the mean CAVI and radial diffusivity in the anterior thalamic radiation and the corona radiata; isotropic volume fraction in the anterior thalamic radiation and the corona radiata; and myelin volume fraction in the superior longitudinal fasciculus (P < .05). Additionally, partial correlation coefficients were observed for the significant associations of executive function with radial diffusivity and myelin volume fraction (P < .05).

CONCLUSIONS

Arterial stiffness could be associated with demyelination rather than axonal degeneration.

2-Arylquinolines as novel anticancer agents with dual EGFR/FAK kinase inhibitory activity: synthesis, biological evaluation, and molecular modelling insights

In this study, different assortments of 2-arylquinolines and 2,6-diarylquinolines have been developed. Recently, we have developed a new series of 6,7-dimethoxy-4-alkoxy-2-arylquinolines as Topoisomerase I (TOP1) inhibitors with potent anticancer activity. Utilising the SAR outputs from this study, we tried to enhance anticancer and TOP1 inhibitory activities. Though target quinolines demonstrated potent antiproliferative effect, specifically against colorectal cancer DLD-1 and HCT-116, they showed weak TOP1 inhibition which may be attributable to their non-coplanarity. Thereafter, screening against kinase panel revealed their dual inhibitory activity against EGFR and FAK. Quinolines 6f, 6h, 6i, and 20f were the most potent EGFR inhibitors (IC50s = 25.39, 20.15, 22.36, and 24.81 nM, respectively). Meanwhile, quinolines 6f, 6h, 6i, 16d, and 20f exerted the best FAK inhibition (IC50s = 22.68, 14.25, 18.36, 17.36, and 15.36 nM, respectively). Finally, molecular modelling was employed to justify the promising EGFR/FAK inhibition. The study outcomes afforded the first reported quinolines with potent EGFR/FAK dual inhibition.

Reduction of noise induced by power supply lines using phase-locked loop

An experimental implementation for the reduction of power-line noise in delicate signal detection is presented. This implementation improves the signal-to-noise ratio without limiting the bandwidth of the measurement. A sinusoidal wave and its harmonics, both synchronized with the frequency of the power line, are used to cancel out the power supply noise induced in the measurement signal. The wave and the harmonics are generated via a phase-locked loop implementation. Their amplitude and phase are adjusted, and then they are added to the measurement signal using a series of operational amplifiers to compensate for the noise. Although we applied this method to the particular case of scanning tunneling microscopy measurements, considerably improving the image quality, our implementation can be applied to other measurement systems for which noise from the power lines can compromise the signal detection.

Involvement of growth differentiation factor 15 in paradoxical relationship between body mass index and mortality in patients with suspected or known coronary artery disease; The ANOX Study

Background

Obesity is a well-established risk factor for type 2 diabetes mellitus, hypertension and dyslipidemia, leading to coronary artery disease (CAD). Nevertheless, body mass index (BMI) is inversely associated with cardiovascular (CV) mortality in patients with cardiac disorders, termed “obesity paradox”. However, the underlying mechanism remains unclear.

Purpose

To clarify important factors involved in the pathogenesis of obesity paradox.

Methods

Using data from a multicenter, prospective cohort of 2,418 patients with suspected or known CAD enrolled in the ANOX study, we assessed the relationship between BMI at baseline and the incidence of CV death over 3 years, and investigated the involvement of several endocrine factors which were previously reported to have some roles in obesity and heart diseases, such as adiponectin, N-terminal pro-brain natriuretic peptide (NT-proBNP) and growth differentiation factor 15 (GDF-15), in the relationship between BMI and CV death.

Results

In Kaplan-Meier analyses, the lower quartiles of BMI and the higher quartiles of adiponectin levels were paradoxically associated with the higher cumulative incidence of CV death. To clarify the important factors involved in the paradoxical association between BMI or adiponectin and mortality, we first investigated independent determinants for BMI and adiponectin levels respectively, using multiple stepwise regression analyses among many clinical factors, and then narrow down the prognostic factors commonly associated with BMI and adiponectin, which were age, hemoglobin and NT-proBNP. Interestingly, circulating levels of GDF15 were significantly correlated with NT-proBNP levels, and the presence of anemia raised the gradient of the correlation line in a scatter plot (without anemia, r=0.139, p&lt;0.0001; with anemia, r=0.228, p&lt;0.0001). Moreover, the highest GDF15 quartile showed significantly lower BMI and higher adiponectin levels compared to the lower quartiles (p&lt;0.001 and p&lt;0.001, respectively, by Student t-test). In Cox proportional hazard models, hazard ratios (HRs) of BMI (per 1-unit increase) were 0.90 (95% confidence interval [CI], 0.85–0.96) for CV death. Additional adjustment for hemoglobin, NT-proBNP, adiponectin or GDF15 diminished the statistical significance (HR, 0.92 [95% CI, 0.87–0.99], 0.95 [0.89–1.01], 0.92 [0.87–0.99], or 0.93 [0.87–0.99], respectively).

Conclusions

The lower BMI and the higher adiponectin levels were paradoxically associated with the higher incidence of CV death in patients with CAD. This paradox may be mediated by cardiac endocrine factors induced by cardiac stresses, including GDF-15 in addition to natriuretic peptides.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The ANOX study is supported by a Grant-in-Aid for Clinical Research from the National Hospital Organization.

Association of beta blocker use with new-onset heart failure and mortality in atrial fibrillation without pre-existing heart failure: the Fushimi AF registry

Background

Heart failure (HF) is one of the major complications in atrial fibrillation (AF). We previously reported that not a few AF patients without pre-existing HF (defined as prior HF hospitalization, New York Heart Association functional class≥2, or left ventricular ejection fraction (LVEF)&lt;40%) subsequently developed new-onset HF. Beta blockers are the established therapy for HF, but it remains unclear whether beta blockers prevent new-onset HF and improve outcomes in AF patients without preexisting HF.

Methods

In the Fushimi AF registry, 778 of 3,262 patients without pre-existing HF were receiving beta blockers at baseline. We investigated the incidence of new-onset HF defined as cardiac death or HF hospitalization, and all-cause death in a propensity-matched cohort (N=1,198; mean age, 71 years; 39% female; mean LVEF, 66%). Additionally, annual follow-up prescription data before the onset of events were collected in 294 of patients with beta blockers and 395 of those without beta blockers. We also investigated the association of starting or stopping beta blockers with the incidence of new-onset HF and all-cause death.

Results

During the median follow-up of 5.8 years, new-onset HF and all-cause death occurred in 77 (12.9%) and 118 (19.7%) of patients with beta blockers, and 70 (11.7%) and 131 (21.9%) of those without beta blockers, respectively. Incidence of new-onset HF was comparable between patients with and without beta blockers (Figure 1), and incidence of all-cause death was also comparable between the two groups (Figure 2). In exploratory subgroup analyses, there was no interaction in the association of beta blockers with the incidence of events, except for pulse rate for new-onset HF and left atrial size for all-cause death. Hazard ratio of beta blockers for new-onset HF tended to be lower in patients with higher pulse rates (&gt;84 bpm) (Figure 1), and that for all-cause death was lower in those without left atrial enlargement (Figure 2). Of patients with follow-up prescription data, beta blockers were stopped in 55 (18.7%) and started in 97 (24.6%) patients, respectively. Patients with starting beta blockers had higher pulse rate (78.5±17.3 vs 74.9±13.9 bpm; p=0.03) and more symptomatic AF (58.8% vs 46.0%; p=0.03) compared to those without starting beta blockers, while there was no difference in baseline characteristics between those with and without stopping beta blockers. During the follow-up, the incidences of new-onset HF and all-cause death were also comparable between the patients with and without stopping beta blockers and those with and without starting beta blockers.

Conclusion

Beta blockers were not associated with the incidence of new-onset HF and all-cause death in AF patients without pre-existing HF. However, the exploratory subgroup analyses suggested the existence of subjects who may benefit from beta blockers.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boehringer Ingelheim, Bayer Healthcare, Pfizer, Bristol-Myers Squibb, Astellas Pharma, AstraZeneca, Daiichi Sankyo, Novartis Pharma, MSD, Sanofi-Aventis, and Takeda Pharmaceutical.

Vascular endothelial factor C and D in patients with heart failure with preserved, mildly reduced, and reduced ejection fraction: the PREHOSP-CHF study

Background

The lymphatic system has been suggested to play an important role in cardiovascular diseases including heart failure (HF). Vascular endothelial growth factor C (VEGF-C) and D (VEGF-D) are key regulators of lymphangiogenesis, and we recently reported the association of low VEGF-C with the risk of all-cause death and high VEGF-D with the risk of HF hospitalization in patients with HF.

Purpose

To investigate the association of VEGF-C and VEGF-D with prognosis in patients with HF with preserved ejection fraction (EF) (HFpEF: EF≥50%), mildly reduced EF (HFmrEF: EF, 40–49%), and reduced EF (HFrEF: EF&lt;40%).

Methods

The PREHOSP-CHF study is a multicenter prospective cohort study to determine the predictive value of angiogenesis-related biomarkers in HF. A total of 1,024 patients (mean age 75.5±12.6 years; 58.7% male) admitted to acute decompensated HF were included in the analyses. Serum levels of VEGF-C and VEGF-D, as well as N-terminal pro B-type natriuretic peptide (NT-proBNP), high sensitivity cardiac troponin-I (hs-cTnI), high sensitivity C reactive protein, were measured at the time of discharge. Patients were followed-up over two years.

Results

The numbers of HFpEF, HFmrEF, and HFrEF were 429 (41.9%), 186 (18.2%), and 409 (39.9%), respectively. HFpEF patients were older, more likely to be female, and had more hypertension, atrial fibrillation, and anemia, but less coronary artery disease. NT-proBNP and hs-cTnI levels increased with decreasing EF. VEGF-C levels decreased with increasing EF (median [interquartile range]: HFpEF, 4508 [3318–5919] pg/ml; HFmrEF, 4719 [3663–6203] pg/ml; HFrEF, 5023 [3804–6382] pg/ml), whereas VEGF-D levels were comparable among the three EF groups (HFpEF, 404.6 [293.1–560.3] pg/ml; HFmrEF, 386.0 [298.5–556.3] pg/ml; HFrEF, 414.2 [296.1–557.3] pg/ml). In multivariate stepwise logistic regression analyses, anemia and high NT-proBNP were independently associated with low VEGF-C levels, and high NT-proBNP was independently associated with high VEGF-D levels, across all the EF groups. During the follow-up, incidences of all-cause death and HF hospitalizations were similar among the three EF groups (log-rank P=0.6 for all-cause death, and log-rank P=0.3 for HF hospitalization). On multivariate Cox proportional hazard analyses including established risk factors and cardiovascular biomarkers, VEGF-C levels tended to be inversely associated with the incidence of all-cause death in patients with HFpEF and HFrEF (Figure). On the contrary, VEGF-D levels were significantly and positively associated with the incidence of HF hospitalization in patients with HFpEF, and tended to be positively associated with it in patients with HFmrEF and HFrEF (Figure).

Conclusions

Low VEGF-C was associated with the risk of all-cause death in patients with HFpEF and HFrEF, while high VEGF-D was associated with the risk of HF hospitalization especially in HFpEF.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Grant-in-Aid for Clinical Research from the National Hospital Organization

Clinical characteristics and outcomes of atrial fibrillation patients with peripheral artery disease: the Fushimi AF Registry

Background

Atrial fibrillation (AF) represents the common arrhythmia and increases the risk of thromboembolism. Risk assessment for thromboembolism is important for the management of AF patients. Peripheral artery disease (PAD) is identified as a risk factor for thromboembolism in CHA2DS2-VASc score. However, there are little data on clinical characteristics and cardiovascular events of AF patients with PAD.

Purpose

In this study, we investigated the clinical characteristics and outcomes of AF patients with PAD.

Methods

The Fushimi AF Registry, a community-based prospective survey, was designed to enroll all of the AF patients who visited the participating medical institutions in Fushimi-ku, Kyoto, Japan. The inclusion criterion of the registry is the documentation of AF at 12-lead electrocardiogram or Holter monitoring at any time, and there are no exclusion criteria. We started to enroll patients from March 2011 and follow up data including prescription status were available in 4,464 patients from March 2011 to August 2021. Median follow-up period was 1,848 days.

Results

Of 4,464 patients, 183 patients had PAD (4.1%; PAD group). The mean age was higher in PAD group than no-PAD group (PAD group vs. no-PAD group: 76.7 vs. 73.5; p&lt;0.01). Patients with PAD had more co-morbidities such as stroke, systemic embolism, congestive heart failure, hypertension, diabetes mellitus, dyslipidemia coronary artery disease and chronic kidney disease than those without PAD. Thus, CHADS2 score, CHA2DS2-VASc score and HAS-BLED score were higher in PAD group than no-PAD group (2.81 vs. 2.00; p&lt;0.01, 5.17 vs. 3.30; p&lt;0.01, 2.42 vs. 1.71; p&lt;0.01, respectively). The proportion of patients with oral anticoagulant was similar between the two groups and the proportion of patients with antiplatelet drug was higher in PAD group than no-PAD group (59.0% vs. 55.6%; p=0.36, 62.9% vs. 24.7%; p&lt;0.01, respectively). The incidences of all-cause death, cardiac death and myocardial infarction were higher in PAD group than no-PAD group (11.4 vs. 4.6 per 100 person-years; log-rank p&lt;0.01, 1.7 vs. 0.8 per 100 person-years; log-rank p&lt;0.01, 1.2 vs. 0.2 per 100 person-years; log-rank p&lt;0.01). However, the incidence of stroke or systemic embolism was similar between the two groups (2.9 vs. 2.2 per 100 person-years, log-rank p=0.19). Finally, the incidence of composite of cardiac death, stroke, systemic embolism or myocardial infarction was higher in PAD group than no-PAD group (6.0 vs. 3.0 per 100 person-years; log-rank p&lt;0.01).

Conclusion

AF patients with PAD had significantly higher risk for death and cardiac events, whereas the incidence of thromboembolism was similar between AF patients with and without PAD.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Agency for Medical Research and Development

Associations of soluble fms-like tyrosine kinase-1 with cardiovascular events and stroke in patients with atrial fibrillation and suspected or known coronary artery disease: the EXCEED-J study

Background

Atrial fibrillation (AF) increases the risk of stroke. Soluble fms-like tyrosine kinase-1 (sFlt-1), a vascular endothelial growth factor (VEGF) antagonist, has been suggested as a marker of endothelial dysfunction, which are associated with both AF and coronary artery disease (CAD). Recently, we demonstrated that sFlt-1 is independently associated with major adverse cardiovascular (CV) events (MACE) in patients with suspected or known CAD. However, the prognostic utility of sFlt-1 in patients with AF remains unknown.

Methods

Using data from a multicenter, prospective cohort of 3255 patients with suspected or known CAD, we investigated whether AF modifies the prognostic utility of sFlt-1. Heparin-free serum levels of sFlt-1, N-terminal pro-brain natriuretic peptide, high-sensitivity cardiac troponin-I, high-sensitivity C-reactive protein, cystatin C, neutrophil gelatinase-associated lipocalin, VEGF, and placental growth factor were measured in 324 patients with AF and 2931 patients without AF. The primary outcome was MACE defined as a composite of CV death, nonfatal myocardial infarction, and nonfatal stroke. The secondary outcomes were all-cause death, CV death, stroke, heart failure (HF) hospitalization, and coronary/peripheral artery revascularization. The biomarkers were natural log-transformed for use as continuous variables.

Results

After adjustment for potential clinical confounders including anticoagulant drug use, sFlt-1 was significantly associated with MACE (hazard ratio for 1 standard deviation increase [HR], 1.55; 95% confidence interval [CI], 1.14–2.08), CV death (HR, 1.68; 95% CI, 1.10–2.48), and stroke (HR, 1.89; 95% CI, 1.16–3.10), but not with all-cause death (HR, 1.32; 95% CI, 0.99–1.73), HF hospitalization (HR, 0.97; 95% CI, 0.73–1.25), or revascularization (HR, 0.99; 95% CI, 0.74–1.28) in patients with AF, whereas sFlt-1 was significantly associated with MACE (HR, 1.19; 95% CI, 1.02–1.37), all-cause death (HR, 1.19; 95% CI, 1.05–1.34), CV death (HR, 1.26; 95% CI, 1.03–1.48), and HF hospitalization (HR, 1.26; 95% CI, 1.11–1.42), but not with stroke (HR, 1.06; 95% CI, 0.81–1.33) or revascularization (HR, 1.01; 95% CI, 0.95–1.07) in patients without AF. Among other biomarkers, only VEGF was significantly associated with MACE (HR, 1.55; 95% CI, 1.02–2.44), and no biomarkers were significantly associated with CV death or stroke in patients with AF. sFlt-1 added incremental prognostic information for MACE (P=0.005 for net reclassification improvement [NRI], P=0.026 for integrated discrimination improvement [IDI]) and stroke (P=0.034 for NRI, P=0.018 for IDI), but not for CV death (P=0.021 for NRI, P=0.134 for IDI), to the model with potential clinical confounders in patients with AF.

Conclusions

sFlt-1 independently predicted MACE and stroke in patients with AF and suspected or known CAD. sFlt-1 may serve as a novel prognostic biomarker to stratify the risk of MACE and stroke in patients with AF.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Health Labour Sciences Research Grant (2013-2014), AMED (2015-2017, Grant Number JP17ek0210008)

Association of cardiothoracic ratio with heart failure hospitalization in patients with atrial fibrillation: the Fushimi AF Registry

Background

Chest radiography is the most common diagnostic imaging test in clinical medicine, and the cardiothoracic ratio (CTR) is a readily available and non-invasive tool with which to assess the volume status and cardiomegaly. However, it remains unknown whether CTR on chest radiography is associated with the incidence of HF hospitalization in AF patients remains unclear.

Methods

The Fushimi AF Registry is a community-based prospective survey of AF patients in Fushimi-ku, Kyoto, Japan. The inclusion criterion of the registry is the documentation of AF at 12-lead electrocardiogram or Holter monitoring at any time, and there are no exclusion criteria. We started to enroll patients from March 2011, and follow-up data were available for 4,489 patients by the end of August 2021. In the present study, 3,727 patients with available data of CTR were examined. We divided the patients into two groups according to their CTR at baseline; Higher group (CTR ≥50.0%, n=2,696) and Lower group (CTR &lt;50.0%, n=1,031), and compared the clinical background and outcomes between the two groups.

Results

The proportion of female was grater in Higher group, and the patients in Higher group were older. The patients in Higher group had higher prevalence of HF, hypertension and chronic kidney disease. During the median follow-up of 3,033 days, in Kaplan-Meier analysis, the incidence rates of HF hospitalization were higher in Higher group (Higher group: 2.5% per person-year vs. Lower group: 1.1%; p&lt;0.01). Multivariate Cox proportional hazards regression analysis revealed that higher CTR (≥50.0%) was an independent determinant of the incidence of HF hospitalization. Furthermore, when we divided the patients into four groups based on the quartile of CTR; Q1 (CTR&lt;49.0%), Q2 (49.0≤CTR&lt;53.8%), Q3 (53.8≤CTR&lt;59.0%), Q4 (59.0%≤CTR), the incidence of HF hospitalization was more frequent in patients with higher CTR, regardless of the presence or absence of prior hospitalization for HF (Figure).

Conclusion

In Japanese AF patients, patients with higher CTR had significantly higher incidence of HF hospitalization, regardless of the prevalence of prior hospitalization for HF.

Funding Acknowledgement

Type of funding sources: None.

Serum amyloid A-low-density-lipoprotein complex and mortality in patients with suspected or known coronary artery disease: the ANOX study

Background

Serum amyloid A-low-density-lipoprotein (SAA-LDL) is a complex formed from the oxidative interaction between SAA and LDLs. A relatively small-scale study has shown that circulating SAA-LDL levels may serve as a prognostic marker in patients with stable coronary artery disease (CAD). However, the prognostic value of SAA-LDL should be confirmed in a larger-scale cohort study.

Methods

Using data from a multicenter, prospective cohort of 2416 patients with suspected or known CAD enrolled in the ANOX (Development of Novel Biomarkers Related to Angiogenesis or Oxidative Stress to Predict Cardiovascular Events) study, we assessed the prognostic value of serum levels of SAA-LDL. The primary outcome was all-cause death. The secondary outcomes were cardiovascular death and major adverse cardiovascular events (MACE) defined as a composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. Patients were followed up over 3 years.

Results

Stepwise regression analysis including baseline data on potential clinical confounders (i.e., age, sex, body mass index, hypertension, dyslipidemia, diabetes, current smoking, estimated glomerular filtration rate, the Gensini score, previous myocardial infarction, previous stroke, previous heart failure hospitalization, atrial fibrillation, malignancies, anemia, antihypertensive drug use, statin use, and aspirin use) and established cardiovascular biomarkers (i.e., N-terminal pro-brain natriuretic peptide, high-sensitivity cardiac troponin I [hs-cTnI], and high-sensitivity C-reactive protein [hs-CRP]) revealed that independent determinants of SAA-LDL levels were female sex, dyslipidemia, the Gensini score, absence of statin use, hs-cTnI, and hs-CRP. After adjusting for potential clinical confounders and established cardiovascular biomarkers, the highest quartile of SAA-LDL levels (vs. the lowest quartile) was significantly associated with the incidence of all-cause death (hazard ratio [HR], 1.51; 95% confidence interval [CI], 1.02–2.26), but not with that of cardiovascular death (HR, 1.11; 95% CI, 0.59–2.10) or MACE (HR, 1.57; 95% CI, 0.97–2.57). Stratified analyses revealed that this association was pronounced in patients with low hs-cTnI (&lt;75th percentile) (HR, 1.85; 95% CI, 1.06–3.30) and in patients with low hs-CRP levels (≤1.0 mg/L) (HR, 2.30; 95% CI, 1.17–4.79).

Conclusions

Elevated SAA-LDL levels were independently associated with the risk of all-cause death in patients with suspected or known CAD. The SAA-LDL level appears to serve as a prognostic biomarker for risk stratification in relatively low-risk patients with low hs-cTnI (&lt;75th percentile) or low hs-CRP (≤1.0 mg/L).

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The ANOX study is supported by a Grant-in-Aid for Clinical Research from the National Hospital Organization.

The association of left ventricular ejection fraction with incident heart failure in patients with atrial fibrillation

Background

Atrial fibrillation (AF) increases the risk of incident heart failure (HF). Left ventricular ejection fraction (LVEF) is an important prognostic parameter in patients with HF. However, little is known regarding the association of LVEF with incident HF in patients with AF.

Purpose

The aim of this study is to investigate the relationship between LVEF at enrollment and incidence of HF hospitalization during follow-up period in patients with AF.

Methods

The Fushimi AF Registry is a community-based prospective survey of patients with AF in Fushimi-ku, Kyoto, Japan. The inclusion criterion of the registry is the documentation of AF at 12-lead electrocardiogram or Holter monitoring at any time, and there are no exclusion criteria. We started to enroll patients from March 2011, and follow-up data were available for 4,489 patients by the end of August 2021. In the present study, we investigated 3,544 patients with the data of LVEF at enrollment. We divided the patients into 4 groups stratified by LVEF (reduced LVEF [LVEF &lt;40%], mildly reduced LVEF [LVEF: 40–49%], slightly reduced LVEF [LVEF: 50–59%], and normal LVEF [LVEF ≥60%]), and compared the backgrounds and outcomes between these 4 groups.

Results

Of 3,544 patients, the mean age was 73.6±10.7 years, 1,420 (40%) were female, 1,781 (50%) were paroxysmal AF, and 1,085 (30%) had pre-existing HF. The mean CHADS2 and CHA2DS2-VASc scores were 2.1±1.3 and 3.4±1.7, respectively. The mean LVEF at enrollment was 63±12% (reduced LVEF: 197 [6%], mildly reduced LVEF: 250 [7%], slightly reduced LVEF: 532 [15%] and normal LVEF: 2,565 [72%], respectively). Patients with lower LVEF demonstrated lower prevalence of female and paroxysmal AF, and had a higher CHADS2 and CHA2DS2-VASc scores (all P&lt;0.01). A total of 605 patients were hospitalized for HF during the median follow-up period of 5.5 years, corresponding to an annual incidence of 3.4% per person-year. Kaplan-Meier curves demonstrated that LVEF at enrollment could stratify the incidence of HF hospitalization during follow-up in patients with AF (Picture 1). Multivariable Cox regression analysis revealed that lower LVEF strata were significantly associated with the increased risk of HF hospitalization even after adjustment by age, sex, type of AF and CHA2DS2-VASc score (Picture 1). An increased risk of HF hospitalization was observed even in patients with mildly reduced LVEF (adjusted hazard ratio: 2.56, 95% CI: 1.99–3.29) as well as in those with slightly reduced LVEF (adjusted hazard ratio: 1.79, 95% CI: 1.45–2.22) compared with those with normal LVEF. These results were also the case in AF patients without pre-existing HF (Picture 2).

Conclusion

LVEF at enrollment could stratify the incidence of HF hospitalization in patients with AF, suggesting the importance of measuring LVEF in all patients with AF. Even mildly (LVEF: 40–49%) or slightly (LVEF: 50–59%) reduced LVEF was independently associated with the risk of incident HF in patients with AF.

Funding Acknowledgement

Type of funding sources: None.

Brown adipose tissue dysfunction promotes heart failure via a trimethylamine N-oxide-dependent mechanism

Low body temperature predicts a poor outcome in patients with heart failure, but the underlying pathological mechanisms and implications are largely unknown. Brown adipose tissue (BAT) was initially characterised as a thermogenic organ, and recent studies have suggested it plays a crucial role in maintaining systemic metabolic health. While these reports suggest a potential link between BAT and heart failure, the potential role of BAT dysfunction in heart failure has not been investigated. Here, we demonstrate that alteration of BAT function contributes to development of heart failure through disorientation in choline metabolism. Thoracic aortic constriction (TAC) or myocardial infarction (MI) reduced the thermogenic capacity of BAT in mice, leading to significant reduction of body temperature with cold exposure. BAT became hypoxic with TAC or MI, and hypoxic stress induced apoptosis of brown adipocytes. Enhancement of BAT function improved thermogenesis and cardiac function in TAC mice. Conversely, systolic function was impaired in a mouse model of genetic BAT dysfunction, in association with a low survival rate after TAC. Metabolomic analysis showed that reduced BAT thermogenesis was associated with elevation of plasma trimethylamine N-oxide (TMAO) levels. Administration of TMAO to mice led to significant reduction of phosphocreatine and ATP levels in cardiac tissue via suppression of mitochondrial complex IV activity. Genetic or pharmacological inhibition of flavin-containing monooxygenase reduced the plasma TMAO level in mice, and improved cardiac dysfunction in animals with left ventricular pressure overload. In patients with dilated cardiomyopathy, body temperature was low along with elevation of plasma choline and TMAO levels. These results suggest that maintenance of BAT homeostasis and reducing TMAO production could be potential next-generation therapies for heart failure.

Coagulation factors promote brown adipose tissue dysfunction and abnormal systemic metabolism in obesity

Brown adipose tissue (BAT) has a role in maintaining systemic metabolic health in rodents and humans. Here, we show that metabolic stress induces BAT to produce coagulation factors, which then-together with molecules derived from the circulation-promote BAT dysfunction and systemic glucose intolerance. When mice were fed a high-fat diet (HFD), the levels of tissue factor, coagulation Factor VII (FVII), activated coagulation Factor X (FXa), and protease-activated receptor 1 (PAR1) expression increased significantly in BAT. Genetic or pharmacological suppression of coagulation factor-PAR1 signaling in BAT ameliorated its whitening and improved thermogenic response and systemic glucose intolerance in mice with dietary obesity. Conversely, the activation of coagulation factor-PAR1 signaling in BAT caused mitochondrial dysfunction in brown adipocytes and systemic glucose intolerance in mice fed normal chow. These results indicate that BAT produces endogenous coagulation factors that mediate pleiotropic effects via PAR1 signaling under metabolic stress.