SPTLC2 variants are associated with early-onset ALS and FTD due to aberrant sphingolipid synthesis

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a devastating, incurable neurodegenerative disease. A subset of ALS patients manifests with early-onset and complex clinical phenotypes. We aimed to elucidate the genetic basis of these cases to enhance our understanding of disease etiology and facilitate the development of targeted therapies.

METHODS

Our research commenced with an in-depth genetic and biochemical investigation of two specific families, each with a member diagnosed with early-onset ALS (onset age of <40 years). This involved whole-exome sequencing, trio analysis, protein structure analysis, and sphingolipid measurements. Subsequently, we expanded our analysis to 62 probands with early-onset ALS and further included 440 patients with adult-onset ALS and 1163 healthy controls to assess the prevalence of identified genetic variants.

RESULTS

We identified heterozygous variants in the serine palmitoyltransferase long chain base subunit 2 (SPTLC2) gene in patients with early-onset ALS. These variants, located in a region closely adjacent to ORMDL3, bear similarities to SPTLC1 variants previously implicated in early-onset ALS. Patients with ALS carrying these SPTLC2 variants displayed elevated plasma ceramide levels, indicative of increased serine palmitoyltransferase (SPT) activity leading to sphingolipid overproduction.

INTERPRETATION

Our study revealed novel SPTLC2 variants in patients with early-onset ALS exhibiting frontotemporal dementia. The combination of genetic evidence and the observed elevation in plasma ceramide levels establishes a crucial link between dysregulated sphingolipid metabolism and ALS pathogenesis. These findings expand our understanding of ALS's genetic diversity and highlight the distinct roles of gene defects within SPT subunits in its development.

De Novo Variants Found in Three Distinct Schizophrenia Populations Hit a Common Core Gene Network Related to Microtubule and Actin Cytoskeleton Gene Ontology Classes

Schizophrenia (SZ) is a heterogeneous and debilitating psychiatric disorder with a strong genetic component. To elucidate functional networks perturbed in schizophrenia, we analysed a large dataset of whole-genome studies that identified SNVs, CNVs, and a multi-stage schizophrenia genome-wide association study. Our analysis identified three subclusters that are interrelated and with small overlaps: GO:0007017~Microtubule-Based Process, GO:00015629~Actin Cytoskeleton, and GO:0007268~SynapticTransmission. We next analysed three distinct trio cohorts of 75 SZ Algerian, 45 SZ French, and 61 SZ Japanese patients. We performed Illumina HiSeq whole-exome sequencing and identified de novo mutations using a Bayesian approach. We validated 88 de novo mutations by Sanger sequencing: 35 in French, 21 in Algerian, and 32 in Japanese SZ patients. These 88 de novo mutations exhibited an enrichment in genes encoding proteins related to GO:0051015~actin filament binding (p = 0.0011) using David, and enrichments in GO: 0003774~transport (p = 0.019) and GO:0003729~mRNA binding (p = 0.010) using Amigo. One of these de novo variant was found in CORO1C coding sequence. We studied Coro1c haploinsufficiency in a Coro1c+/- mouse and found defects in the corpus callosum. These results could motivate future studies of the mechanisms surrounding genes encoding proteins involved in transport and the cytoskeleton, with the goal of developing therapeutic intervention strategies for a subset of SZ cases.

MAST4 promotes primary ciliary resorption through phosphorylation of Tctex-1

The primary cilium undergoes cell cycle-dependent assembly and disassembly. Dysregulated ciliary dynamics are associated with several pathological conditions called ciliopathies. Previous studies showed that the localization of phosphorylated Tctex-1 at Thr94 (T94) at the ciliary base critically regulates ciliary resorption by accelerating actin remodeling and ciliary pocket membrane endocytosis. Here, we show that microtubule-associated serine/threonine kinase family member 4 (MAST4) is localized at the primary cilium. Suppressing MAST4 blocks serum-induced ciliary resorption, and overexpressing MAST4 accelerates ciliary resorption. Tctex-1 binds to the kinase domain of MAST4, in which the R503 and D504 residues are key to MAST4-mediated ciliary resorption. The ciliary resorption and the ciliary base localization of phospho-(T94)Tctex-1 are blocked by the knockdown of MAST4 or the expression of the catalytic-inactive site-directed MAST4 mutants. Moreover, MAST4 is required for Cdc42 activation and Rab5-mediated periciliary membrane endocytosis during ciliary resorption. These results support that MAST4 is a novel kinase that regulates ciliary resorption by modulating the ciliary base localization of phospho-(T94)Tctex-1. MAST4 is a potential new target for treating ciliopathies causally by ciliary resorption defects.

Hydrogen sulfide and polysulfides induce GABA/glutamate/D-serine release, facilitate hippocampal LTP, and regulate behavioral hyperactivity

Hydrogen sulfide (H2S) and polysulfides (H2Sn, n ≥ 2) are signaling molecules produced by 3-mercaptopyruvate sulfurtransferase (3MST) that play various physiological roles, including the induction of hippocampal long-term potentiation (LTP), a synaptic model of memory formation, by enhancing N-methyl-D-aspartate (NMDA) receptor activity. However, the presynaptic action of H2S/H2Sn on neurotransmitter release, regulation of LTP induction, and animal behavior are poorly understood. Here, we showed that H2S/H2S2 applied to the rat hippocampus by in vivo microdialysis induces the release of GABA, glutamate, and D-serine, a co-agonist of NMDA receptors. Animals with genetically knocked-out 3MST and the target of H2S2, transient receptor potential ankyrin 1 (TRPA1) channels, revealed that H2S/H2S2, 3MST, and TRPA1 activation play a critical role in LTP induction, and the lack of 3MST causes behavioral hypersensitivity to NMDA receptor antagonism, as in schizophrenia. H2S/H2Sn, 3MST, and TRPA1 channels have therapeutic potential for psychiatric diseases and cognitive deficits.

Impairment of serine transport across the blood-brain barrier by deletion of Slc38a5 causes developmental delay and motor dysfunction

Brain L-serine is critical for neurodevelopment and is thought to be synthesized solely from glucose. In contrast, we found that the influx of L-serine across the blood-brain barrier (BBB) is essential for brain development. We identified the endothelial Slc38a5, previously thought to be a glutamine transporter, as an L-serine transporter expressed at the BBB in early postnatal life. Young Slc38a5 knockout (KO) mice exhibit developmental alterations and a decrease in brain L-serine and D-serine, without changes in serum or liver amino acids. Slc38a5-KO brains exhibit accumulation of neurotoxic deoxysphingolipids, synaptic and mitochondrial abnormalities, and decreased neurogenesis at the dentate gyrus. Slc38a5-KO pups exhibit motor impairments that are affected by the administration of L-serine at concentrations that replenish the serine pool in the brain. Our results highlight a critical role of Slc38a5 in supplying L-serine via the BBB for proper brain development.

Epitope Mapping of Anti-Mouse CCR3 Monoclonal Antibodies (C3Mab-6 and C3Mab-7)

One of G protein-coupled receptors, CC chemokine receptor 3 (CCR3), is expressed in eosinophils, basophils, a subset of Th2 lymphocytes, mast cells, and airway epithelial cells. CCR3 levels in the serum of colorectal cancer patients are significantly higher than in control groups. Moreover, CCR3 is essential for recruiting eosinophils into the lung. Therefore, CCR3 is considered both a therapeutic target for colorectal cancer and allergic diseases. Previously, we established anti-mouse CCR3 (mCCR3) monoclonal antibodies (mAbs), C₃Mab-6 (rat IgG₁, kappa) and C₃Mab-7 (rat IgG₁, kappa), by immunizing a rat with an N-terminal peptide of mCCR3. These mAbs can be used in flow cytometry and enzyme-linked immunosorbent assays. In this study, we performed the epitope mapping of C₃Mab-6 and C₃Mab-7 using alanine scanning. The reactivity between these mAbs and point mutants of mCCR3 were analyzed using flow cytometry. The results indicated that Phe3, Asn4, Thr5, Asp6, Glu7, Lys9, Thr10, and Glu13 of mCCR3 are essential for C₃Mab-6 binding, whereas Phe15 and Glu16 are essential for C₃Mab-7 binding.

Epitope Mapping of the Novel Anti-Human CCR9 Monoclonal Antibody (C9Mab-11) by 2 × Alanine Scanning

We recently developed a novel anti-human C-C chemokine receptor 9 (hCCR9) monoclonal antibody (mAb), C₉Mab-11, which is applicable to flow cytometry, western blotting, and enzyme-linked immunosorbent assay (ELISA). This study aims to identify the binding epitope of C₉Mab-11 by using 1 × and 2 × alanine (or glycine) substituted-hCCR9 peptides (1 × and 2 × Ala-scan) by ELISA. According to the 1 × Ala-scan analysis, the response of C₉Mab-11 was diminished against M13A of the hCCR9 peptide, but was not eliminated. In the 2 × Ala-scan analysis, the reactions were abolished in the substitution of P11A-N12A, N12A-M13A, and M13A-A14G of hCCR9 N-terminal peptides. The results indicate that the binding epitope of C₉Mab-11 includes Pro11, Asn12, Met13, and Ala14 of hCCR9, with the region around Met13 being particularly important. The successful identification of the C₉Mab-11 epitope might be useful for the future pathophysiological analysis of hCCR9.

Epitope Mapping of an Anti-EpCAM Monoclonal Antibody (EpMab-37) Using the Alanine Scanning Method

The epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein, and plays critical roles in cell adhesion, proliferation, and tumorigenesis. EpCAM has been considered as a promising target for tumor diagnosis and therapy. Anti-EpCAM monoclonal antibodies (mAbs) have been developed for EpCAM-overexpressed tumors, and several clinical trials have demonstrated promising outcomes. We previously established an anti-EpCAM mAb, EpMab-37 (mouse IgG₁, kappa), using the Cell-Based Immunization and Screening method. EpMab-37 was revealed to recognize the conformational epitope of EpCAM. In this study, we determined the critical epitope of EpMab-37 by flow cytometry using the 1 × alanine scanning (1 × Ala-scan) and the 2 × alanine scanning (2 × Ala-scan) method. We first performed flow cytometry by 1 × Ala-scan using one alanine (or glycine)-substituted EpCAM mutants, which were expressed on Chinese hamster ovary-K1 cells, and found that the EpMab-37 did not recognize the R163A mutant of EpCAM. We next performed flow cytometry by 2 × Ala-scan using two alanine (or glycine) residues-substituted EpCAM mutants, and confirmed that EpMab-37 did not recognize R163A-including mutants of EpCAM. The results indicated that the critical binding epitope of EpMab-37 includes Arg163 of EpCAM.

Epitope Mapping Using the Cell-Based 2 × Alanine Substitution Method About the Anti-mouse CXCR6 Monoclonal Antibody, Cx6Mab-1

An anti-mouse CXC chemokine receptor 6 (mCXCR6) monoclonal antibody (mAb), Cx₆Mab-1, was developed recently. Cx₆Mab-1 is applicable for flow cytometry, Western blotting, and enzyme-linked immunosorbent assay. The purpose of this study is to determine the binding epitope of Cx₆Mab-1 using 2 × alanine mutated mCXCR6. Analysis of flow cytometry revealed that Cx₆Mab-1 did not recognize S8A-A9G, L10A-Y11A, D12A-G13A, and H14A-Y15A mutants of mCXCR6. The results clearly indicate that the binding epitope of Cx₆Mab-1 includes Ser8, Ala9, Leu10, Tyr11, Asp12, Gly13, His14, and Tyr15 of mCXCR6. The successful determination of the Cx₆Mab-1 epitope might contribute to the pathophysiological investigation of mCXCR6.

Antitumor Activities in Mouse Xenograft Models of Canine Fibroblastic Tumor by Defucosylated Mouse-Dog Chimeric Anti-HER2 Monoclonal Antibody (H77Bf)

Human epidermal growth factor receptor 2 (HER2) is a cell surface type I transmembrane glycoprotein that is overexpressed on a variety of solid tumors and transduces the oncogenic signaling upon homo- and heterodimerization with HER families. Anti-HER2 monoclonal antibodies (mAbs) including trastuzumab and its antibody-drug conjugate have been shown to improve patients' survival in HER2-positive breast, gastric, and lung cancers. Canine tumors have advantages as naturally occurring tumor models, and share biological and histological characteristics with human tumors. In this study, we generated a defucosylated version of mouse-dog chimeric anti-HER2 mAb (H77Bf) derived from H₂Mab-77 (mouse IgG₁, kappa). H77Bf possesses the high binding affinity (a dissociation constant: 8.7 × 10^-10 M) for a dog HER2 (dHER2)-expressing canine fibroblastic tumor cell line (A-72). H77Bf exhibited antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity for A-72 cells. Moreover, intraperitoneal administration of H77Bf significantly suppressed the development of A-72 tumor compared with the control dog IgG in a mouse xenograft model. These results indicate that H77Bf exerts antitumor activities against dHER2-expressing canine cancers, which could provide a valuable information for canine cancer treatment.

Defucosylated Mouse-Dog Chimeric Anti-Human Epidermal Growth Factor Receptor 2 Monoclonal Antibody (H77Bf) Exerts Antitumor Activities in Mouse Xenograft Models of Canine Osteosarcoma

Human epidermal growth factor receptor 2 (HER2) has been studied in many human cancer types, and its overexpression and/or gene mutation contribute to the poor prognosis. Therefore, HER2 is an important therapeutic target in various cancer types, including breast and gastric cancers. We previously developed an anti-HER2 monoclonal antibody (mAb), H₂Mab-77 (mouse IgG₁, kappa), which detects HER2 and dog HER2 (dHER2) with high sensitivity and specificity. In this study, we produced a defucosylated mouse-dog chimeric anti-HER2 mAb (H77Bf), and investigated the reactivity against canine osteosarcoma D-17 cells by flow cytometry. Furthermore, we showed that H77Bf exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against D-17 cells in vitro and exhibited the potent antitumor activity in vivo. These results suggest that H77Bf exerts antitumor effects against dHER2-expressing canine tumors and could be valuable as part of an antibody treatment regimen for them.

Establishment of a Sensitive Monoclonal Antibody Against Mouse CCR9 (C9Mab-24) for Flow Cytometry

The CC chemokine receptor 9 (CCR9), also known as CD199, is one of chemokine receptors. The CC chemokine ligand 25 (CCL25) is known to be the only ligand for CCR9. The CCR9-CCL25 interaction plays important roles in chemotaxis of lymphocytes and tumor cell migration. Therefore, CCR9-CCL25 axis is a promising target for tumor therapy and diagnosis. In this study, we established a sensitive and specific monoclonal antibody (mAb) against mouse CCR9 (mCCR9) using N-terminal peptide immunization method. The established anti-mCCR9 mAb, C₉Mab-24 (rat immunoglobulin [IgG]_2a, kappa), reacted with mCCR9-overexpressed Chinese hamster ovary-K1 (CHO/mCCR9) and mCCR9-endogenously expressed cell line, RL2, through flow cytometry. Kinetic analyses using flow cytometry showed that the dissociation constants (K_D) of C₉Mab-24 for CHO/mCCR9 and RL2 cell lines were 6.0 × 10^-9 M and 4.7 × 10^-10 M, respectively. Results indicated that C₉Mab-24 is useful for detecting mCCR9 through flow cytometry, thereby providing a possibility for targeting mCCR9-expressing cells in vivo experiments.

Epitope Mapping of Anti-Mouse CCR3 Monoclonal Antibodies Using Flow Cytometry

The CC chemokine receptor 3 (CCR3) is a receptor for CC chemokines, including CCL5/RANTES, CCL7/MCP-3, and CCL11/eotaxin. CCR3 is expressed on the surface of eosinophils, basophils, a subset of Th2 lymphocytes, mast cells, and airway epithelial cells. CCR3 and its ligands are involved in airway hyperresponsiveness in allergic asthma, ocular allergies, and cancers. Therefore, CCR3 is an attractive target for those therapies. Previously, anti-mouse CCR3 (mCCR3) monoclonal antibodies (mAbs), C₃Mab-3 (rat IgG_2a, kappa), and C₃Mab-4 (rat IgG_2a, kappa) were developed using the Cell-Based Immunization and Screening (CBIS) method. In this study, the binding epitope of these mAbs was investigated using flow cytometry. A CCR3 extracellular domain-substituted mutant analysis showed that C₃Mab-3, C₃Mab-4, and a commercially available mAb (J073E5) recognized the N-terminal region (amino acids 1-38) of mCCR3. Next, alanine scanning was conducted in the N-terminal region. The results revealed that the Ala2, Phe3, Asn4, and Thr5 of mCCR3 are involved in C₃Mab-3 binding, whereas Ala2, Phe3, and Thr5 are essential to C₃Mab-4 binding, and Ala2 and Phe3 are crucial to J073E5 binding. These results reveal the involvement of the N-terminus of mCCR3 in the recognition of C₃Mab-3, C₃Mab-4, and J073E5.

Development of a Novel Anti-Mouse CCR6 Monoclonal Antibody (C6Mab-13) by N-Terminal Peptide Immunization

The CC chemokine receptor 6 (CCR6) is a G protein-coupled receptor family member that is highly expressed in B lymphocytes, certain subsets of effector and memory T cells, and immature dendritic cells. CCR6 has only one chemokine ligand, CCL20. The CCL20-CCR6 axis has been recognized as a therapeutic target for autoimmune diseases and tumor. This study developed specific monoclonal antibodies (mAbs) against mouse CCR6 (mCCR6) using the peptide immunization method. The established anti-mCCR6 mAb, C₆Mab-13 (rat IgG₁, kappa), reacted with mCCR6-overexpressed Chinese hamster ovary-K1 (CHO/mCCR6), and mCCR6-endogenously expressed P388 (mouse lymphoid neoplasma) and J774-1 (mouse macrophage-like) cells in flow cytometry. The dissociation constant (K_D) of C₆Mab-13 for CHO/mCCR6 cells was determined to be 2.8 × 10^-9 M, indicating that C₆Mab-13 binds to mCCR6 with high affinity. In summary, C₆Mab-13 is useful for detecting mCCR6-expressing cells through flow cytometry.

Development of a Sensitive Anti-Human CCR9 Monoclonal Antibody (C9Mab-11) by N-Terminal Peptide Immunization

The C-C chemokine receptor 9 (CCR9) belongs to the G-protein-coupled receptor superfamily, and is highly expressed on the T cells and intestinal cells. CCR9 regulates various immune responses by binding to the C-C chemokine ligand, CCL25, and is involved in inflammatory diseases and tumors. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CCR9 is necessary for treatment and diagnosis. In this study, we established a specific anti-human CCR9 (hCCR9) mAb; C₉Mab-11 (mouse IgG_2a, kappa), using the synthetic peptide immunization method. C₉Mab-11 reacted with hCCR9-overexpressed Chinese hamster ovary-K1 (CHO/hCCR9) and hCCR9-endogenously expressed MOLT-4 (human T-lymphoblastic leukemia) cells in flow cytometry. The dissociation constant (K_D) of C₉Mab-11 for CHO/hCCR9 and MOLT-4 cells were determined to be 1.2 × 10^-9 M and 4.9 × 10^-10 M, respectively, indicating that C₉Mab-11 possesses a high affinity for both exogenously and endogenously hCCR9-expressing cells. Furthermore, C₉Mab-11 clearly detected hCCR9 protein in CHO/hCCR9 cells using western blot analysis. In summary, C₉Mab-11 can be a useful tool for analyzing hCCR9-related biological responses.

Epitope Mapping of an Anti-Mouse CCR2 Monoclonal Antibody (C2Mab-6) Using Enzyme-Linked Immunosorbent Assay

CC chemokine receptor type-2 (CCR2) is a member of the G protein-coupled receptors, and is mainly expressed on cell surface of immune cells. CCR2 binds to its ligand, C-C motif chemokine 2 (also named as monocyte chemoattractant protein-1), which involves in the tumor progression by modulating the tumor microenvironment. Therefore, the monoclonal antibody (mAb) targeting CCR2 could be one of the strategies for cancer treatment. In this study, we investigated the critical epitope of C₂Mab-6, an anti-mouse CCR2 (mCCR2) mAb developed by N-terminal peptides immunization. We first performed enzyme-linked immunosorbent assay (ELISA) using N-terminal peptides of mCCR2 and demonstrated that C₂Mab-6 recognizes 1-19 amino acids of mCCR2. We further performed ELISA using 20 alanine-substituted peptides of mCCR2. C₂Mab-6 lost the reaction to the alanine-substituted peptides of D3A, N4A, M6A, P8A, Q9A, and F10A. These results indicate that the binding epitope of C₂Mab-6 includes Asp3, Asn4, Met6, Pro8, Gln9, and Phe10 of mCCR2.

Antitumor Activity of an Anti-EGFR/HER2 Bispecific Antibody in a Mouse Xenograft Model of Canine Osteosarcoma

The overexpression of epidermal growth factor receptors (EGFRs) has been reported in various human tumors, including breast, gastric, lung, colorectal, and pancreatic cancers. Humanized anti-EGFR and anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibodies (mAbs) have been shown to improve patients' survival. Canine tumors resemble human tumors in the initiation and progression. We previously established a defucosylated mouse-dog chimeric anti-EGFR mAb (E134Bf) and a mouse-dog chimeric anti-HER2 mAb (H77Bf), which exerted antitumor activities in canine tumor xenograft models. Here, we produced E134Bf antibody fused to H77Bf single chain Fv at the light chains (E134Bf-H77scFv). The bispecific E134Bf-H77scFv recognized dog EGFR (dEGFR) and dog HER2 (dHER2)-overexpressed Chinese hamster ovary-K1 cells by flow cytometry. E134Bf-H77scFv also reacted with dEGFR/dHER2-positive canine osteosarcoma D-17 cells, and possesses a high binding-affinity (K_D: 1.3 × 10^-9 M). Furthermore, E134Bf-H77scFv exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against D-17 cells in the presence of canine mononuclear cells and complement, respectively. Moreover, administration of E134Bf-H77scFv suppressed the development of D-17 xenograft tumor in mice early compared with the control dog IgG, E134Bf and H77Bf alone. These results indicate that E134Bf-H77scFv exerts antitumor activities against dEGFR/dHER2-positive canine tumors, and could be a valuable treatment regimen for canine tumors.

Increasing the class of foundational medication for heart failure is associated with improved prognosis in hospitalized patients with heart failure with reduced or mildly reduced ejection fraction

Aim

To clarify the association between changes in the number of foundational medications for heart failure (FMHF) during hospitalization for worsening heart failure and post-discharge prognosis.

Methods and results

We retrospectively analyzed a combined dataset of three large-scale registries of hospitalized patients with heart failure in Japan (NARA-HF, WET-HF, and REALITY-AHF) and included patients already diagnosed with heart failure with reduced or mildly reduced left ventricular ejection fraction (HFr/mrEF) before admission. Patients were stratified by changes in the number of prescribed FMHF classes, namely angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, beta blockers, and mineralocorticoid receptor blockers, from admission to discharge. The primary endpoint was defined as the combined endpoint of heart failure rehospitalization and all-cause death within 1-year of discharge. The cohort consisted of 1,113 patients, and 482 combined endpoints were observed. In total, 413 (37.1%) patients were on increased FMHF (increased group), 607 (54.5%) remained unchanged (unchanged group), and 93 (8.4%) had a decreased number of FMHF (decreased group) at discharge compared to the time of admission. In multivariable analysis, the increased group was associated with a significantly lower incidence of the primary endpoint compared with the unchanged group (hazard ratio 0.56, 95% confidence interval 0.45–0.60; P&lt;0.001) and decreased group (hazard ratio 0.58, 95% confidence interval 0.40–0.84; P=0.004).

Conclusion

Increasing the number of FMHF cases during heart failure hospitalization is associated with a better prognosis in patients with HFr/mrEF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): REALITY registry was funded by the Cardiovascular Research Fund of Japan.WET-HF registry was supported by a Grant-in-Aid for Young Scientists (Y.S. JSPS KAKENHI, 18K15860).

KLMab-1: An Anti-human KLRG1 Monoclonal Antibody for Immunocytochemistry

Immune checkpoint molecules have received attention as targets of cancer immunotherapy. Killer cell lectin-like receptor subfamily G member 1 (KLRG1) is one of the immune checkpoint molecules expressed in CD4⁺ T, CD8⁺ T, and natural killer (NK) cells. KLRG1 exhibits antiviral and antitumor immunity, and its expression in T and NK cells is upregulated by viral infectious diseases and some tumors. Thus, monoclonal antibodies (mAbs) for KLRG1 would be useful tools for the diagnosis and immunotherapy against viral infectious diseases and cancers. We have developed anti-human KLRG1 (hKLRG1) mAb (clone KLMab-1, mouse IgG₁, kappa) by the Cell-Based Immunization and Screening method. We have also demonstrated that KLMab-1 recognizes both exogenous and endogenous hKLRG1 in flow cytometry. In this study, we first showed that KLMab-1 and its recombinant mAb (recKLMab-1) bound to exogenous hKLRG1 overexpressed in Chinese hamster ovary (CHO)-K1 cells, but not in parental CHO-K1 cells, in immunocytochemistry. We next showed that both mAbs detected endogenous hKLRG1 expressed in human NK cells. These results demonstrate that KLMab-1 and recKLMab-1 are available for immunocytochemistry.

Cross-Disorder Analysis of Genic and Regulatory Copy Number Variations in Bipolar Disorder, Schizophrenia, and Autism Spectrum Disorder

BACKGROUND

We aimed to determine the similarities and differences in the roles of genic and regulatory copy number variations (CNVs) in bipolar disorder (BD), schizophrenia (SCZ), and autism spectrum disorder (ASD).

METHODS

Based on high-resolution CNV data from 8708 Japanese samples, we performed to our knowledge the largest cross-disorder analysis of genic and regulatory CNVs in BD, SCZ, and ASD.

RESULTS

In genic CNVs, we found an increased burden of smaller (<100 kb) exonic deletions in BD, which contrasted with the highest burden of larger (>500 kb) exonic CNVs in SCZ/ASD. Pathogenic CNVs linked to neurodevelopmental disorders were significantly associated with the risk for each disorder, but BD and SCZ/ASD differed in terms of the effect size (smaller in BD) and subtype distribution of CNVs linked to neurodevelopmental disorders. We identified 3 synaptic genes (DLG2, PCDH15, and ASTN2) as risk factors for BD. Whereas gene set analysis showed that BD-associated pathways were restricted to chromatin biology, SCZ and ASD involved more extensive and similar pathways. Nevertheless, a correlation analysis of gene set results indicated weak but significant pathway similarities between BD and SCZ or ASD (r = 0.25-0.31). In SCZ and ASD, but not BD, CNVs were significantly enriched in enhancers and promoters in brain tissue.

CONCLUSIONS

BD and SCZ/ASD differ in terms of CNV burden, characteristics of CNVs linked to neurodevelopmental disorders, and regulatory CNVs. On the other hand, they have shared molecular mechanisms, including chromatin biology. The BD risk genes identified here could provide insight into the pathogenesis of BD.

Defucosylated mouse‑dog chimeric anti‑HER2 monoclonal antibody exerts antitumor activities in mouse xenograft models of canine tumors

Human epidermal growth factor receptor 2 (HER2) overexpression has been reported in various types of cancer, including breast, gastric, lung, colorectal and pancreatic cancer. A humanized anti-HER2 monoclonal antibody (mAb), trastuzumab, has been shown to improve survival of patients in HER2-positive breast and gastric cancer. An anti-HER2 mAb, H₂Mab-77 (mouse IgG₁, kappa) was previously developed. In the present study, a defucosylated version of mouse-dog chimeric anti-HER2 mAb (H77Bf) was generated. H77Bf possesses a high binding-affinity [a dissociation constant (K_D): 7.5×10⁻¹⁰ M, as determined by flow cytometric analysis] for dog HER2-overexpressed CHO-K1 (CHO/dHER2) cells. H77Bf highly exerted antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) for CHO/dHER2 cells by canine mononuclear cells and complement, respectively. Moreover, administration of H77Bf significantly suppressed the development of CHO/dHER2 ×enograft tumor in mice compared with the control dog IgG. H77Bf also possesses a high binding-affinity (K_D: 7.2×10⁻¹⁰ M) for a canine mammary gland tumor cell line (SNP), and showed high ADCC and CDC activities for SNP cells. Intraperitoneal administration of H77Bf in mouse xenograft models of SNP significantly suppressed the development of SNP xenograft tumors compared with the control dog IgG. These results indicated that H77Bf exerts antitumor activities against dHER2-positive canine cancers, and could be valuable treatment regimen for canine cancers.

AB0401 THE BASELINE SERUM SOLUBLE TNF RECEPTOR LEVELS ARE ASSOCIATED WITH THE RESPONSE OF RHEUMATOID ARTHRITIS PATIENTS TO JAKinibs

Background

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the multiple joints.

The elucidation of the pathogenesis of RA has progressed dramatically in recent decades, and among the many cytokines involved in the pathogenesis of RA, interleukin (IL)-6 and TNF-α are known to be the major pro-inflammatory cytokines that are abundant in the bloodstream and synovial tissue. JAK inhibitors (JAKinibs) such as tofacitinib and baricitinib are used in the treatment of RA by inhibiting JAK, which in turn inhibits the signaling of various cytokines including IL-6. However, predictors of the response to JAKinibs are still required.

Objectives

We aimed to combine soluble TNF receptor (sTNFR) I, sTNFR II, IL-6, soluble IL-6R (sIL-6R) and soluble gp130 (sgp130) levels to identify groups of JAKinibs responses in RA patients.

Methods

This research is a retrospective study. We reviewed medical records of RA patients initiating JAKinibs between July 2013 and July 2021 in our hospital. The Simplified Disease Activity Index (SDAI) was evaluated at baseline and 3, 6 months after JAKinibs administration. Clinical remission was defined when SDAI decreased ≤ 3.3. Of the 125 patients treated with JAKinibs, 89 patients with 6 months follow-up, valid SDAI and serum available were enrolled. Serum samples were tested for IL-6 (Human IL-6 Quantikine ELISA Kit, R&D systems), sIL-6R (Human soluble IL-6R alpha Quantikine ELISA Kit, R&D systems) and sgp130 (Human soluble gp130 Quantikine ELISA Kit, R&D systems), sTNFR I (Human TNF RI/TNFRSF1A Quantikine ELISA Kit DRT100) and sTNFR II (Human sTNF RII/TNFRSF1B Quantikine ELISA Kit DRT200) using specific ELISAs according to the manufacturer’s instructions. The statistical analyses were performed with EZR 1.55, and p values less than 0.05 were considered significant.

Results

The median age of patients was 62 (IQR: 51 - 72) years and the median of disease duration was 6.0 (2.0 - 16.0) years. Twenty-seven (30.3%) patients were biologics and Jakinibs naive. The baseline SDAI was median 18.9 (12.7 - 27.9). When comparing SDAI-remission group (clinical remission: CR) and non-remission group, there were no significant differences in any of the baseline clinical parameters. There was no significant difference in the serum levels of IL-6, sIL-6R and sgp130 between the CR and non-CR groups, but the serum levels of sTNFR I and sTNFR II in the CR group were significantly lower than non-CR group. Univariate logistic regression analysis suggested Biologics and JAKinibs naive (odds ratio (OR) 3.58, p = 0.015), baseline Log sTNFR II levels (OR 0.013, P=0.034) as predictors of SDAI remission treated with JAKinibs at 6 months. Although not significant, Stage IV (OR 0.211, P=0.082) and baseline Log sTNFR I serum levels (OR 0.013, P=0.065) were associated with clinical remission.

Conclusion

RA patients could be easily stratified prior to JAKinibs intervention with serum sTNFR II and sTNFR I levels, not but IL-6 axis cytokines (IL-6, sIL-6R and sgp130).

Univariate logistic regression analysis for clinical remission in patients treated with JAKinibs.　Odds Ratio[95% C.I.]P ValueAge, year0.973[0.942 - 1.010]0.104Female (%)0.820[0.231 - 2.910]0.759BMI0.968[0.847 - 1.110]0.627Duration, year0.952[0.897 - 1.010]0.110StageIreferrenceII0.857[0.218 - 3.370]0.825III0.444[0.072 - 2.740]0.382IV0.211[0.036 - 1.220]0.082Biologic/JAKi naïve3.580[1.280 - 9.950]0.015JAKi Drug-Baricitinibreferrence-Tofacitinib1.780[0.659 - 4.800]0.256MTX use1.640[0.532 - 5.30]0.390PSL use0.476[0.176 - 1.290]0.143SASP use0.783[0.268 - 2.290]0.654IGU use0.328[0.039 - 2.750]0.304BUC use0.436[0.051 - 3.760]0.450TAC use0.233[0.029 - 1.910]0.1750W IL-6, pg/mL0.991[0.977 - 1.000]0.1980W sIL-6R, ng/mL0.983[0.947 - 1.02]0.3690W sgp130, ng/mL0.998[0.994 - 1.000]0.4440W sTNFR II/I ratio0.808[0.222 - 2.940]0.7460W Log sTNFR II, pg/mL0.002[0.0000653 - 0.634]0.0340W Log sTNFR I, pg/mL0.013[0.000126 - 1.300]0.065

Disclosure of Interests

None declared

AB0362 NEUTROPHIL COUNT REDUCTION 1 MONTH AFTER INITIATING SARILUMAB AND BASELINE SERUM SOLUBLE gp130 LEVELS CAN INDEPENDENTLY PREDICT CLINICAL REMISSION WITHIN 3 MONTH IN RHEUMATOID ARTHRITIS PATIENTS

Background

IL-6 contributes significantly to the chronic inflammatory process of rheumatoid arthritis (RA) and is elevated in serum and synovial fluid of RA patients.

Sarilumab (SRL), a human anti-human IL-6 receptor alpha monoclonal antibody that blocks the signaling originated by the IL-6/IL-6R complex like tocilizumab (TCZ),is an effective treatment. Recently, an association between the therapeutic effect of TCZ and neutropenia after TCZ initiation was reported[1]. Neutropenia is a common adverse event of SRL in patients with RA, but the relationship between reduced neutrophil count and clinical response to SRL is still inconclusive. In EULAR 2020, we reported the association between serum soluble gp130 levels before SRL treatment and the efficacy of SRL[2]. It is also unclear whether there is a relationship between IL-6 axis cytokines and SRL-induced neutropenia.

Objectives

The purpose of this study was to determine whether neutropenia at 1 month by SRL predicts clinical remission within 3 months and whether there is an association between IL-6 axis cytokines levels and SRL-induced neutropenia.

Methods

This research is a retrospective study. We reviewed medical records of RA patients initiating SRL between February 2018 and August 2021 in our hospital. The Clinical Disease Activity Index (CDAI) was evaluated at baseline (before initiating SRL) and 3 months after administration. Clinical remission was defined when CDAI decreased ≤ 2.8. Of the 66 patients treated with SRL, 42 patients with 3 months follow-up, valid CDAI and serum available were enrolled. The ratio of neutrophil counts 1 month after initiating SRL to those at baseline (neutrophil ratio) was also calculated. Serum samples were tested for IL-6 (Human IL-6 Quantikine ELISA Kit, R&D systems), sIL-6R (Human soluble IL-6R alpha Quantikine ELISA Kit, R&D systems) and sgp130 (Human soluble gp130 Quantikine ELISA Kit, R&D systems) using specific ELISAs according to the manufacturer’s instructions. The statistical analyses were performed with EZR 1.55, and p values less than 0.05 were considered significant.

Results

The median age of patients was 69.0 (IQR: 59.3 - 73.8) years and the median of disease duration was 9.0 (3.0 - 16.0) years. Eighteen (42.9%) patients were biologics and Jakinibs naive. The baseline CDAI was median 16.7 (11.5 - 25.8). When comparing CDAI-remission group (clinical remission: CR) and non-CR group, Patients in the CR group had significantly shorter disease duration, were more Biologic and JAKinib naive, and had greater neutropenia 1 month after starting SRL (0.71 vs 0.94, P=0.0252). There was no significant difference in the baseline serum levels of IL-6, sIL-6R between the CR and non-CR groups, but baseline serum sgp130 levels in the CR group tended to be higher than in the non-CR group (264.9 vs 234.2 ng/mL, P=0.0592). Univariate logistic regression analysis suggested Biologics and JAKinibs naive (odds ratio (OR) 6.68, p = 0.0317), baseline serum sgp130 levels (OR 8.608, P=0.0312) as predictors of CDAI remission treated with SRL at 3 months. Although not significant, neutrophil ratio ≤ 0.8 was associated with achieving remission (OR 6.67, P=0.0537). Univariate logistic regression for neutrophil ratio ≤ 0.8 did not show any relevant factors, including higher baseline serum sgp130 levels (OR 1.25, P=0.782).

Conclusion

A 20% or greater decrease in neutrophil count after 1 month of SRL treatment and a high baseline serum sgp130 level independently predict clinical remission within 3 months.

References

[1]Nakajima T, Watanabe R, Hashimoto M, Murata K, Murakami K, Tanaka M, et al. Neutrophil count reduction 1 month after initiating tocilizumab can predict clinical remission within 1 year in rheumatoid arthritis patients. Rheumatol Int. 2021;1rin

[2]Yoshikawa T, Furukawa T, Tamura M, Hashimoto T, Morimoto M, Azuma N, et al. FRI0113 THE BASELINE SOLUBLE GP130 IS ASSOCIATED WITH THE RESPONSE OF RHEUMATOID ARTHRITIS PATIENTS TO SARILUMAB. Ann Rheum Dis. 2020;79(Suppl 1):637.1-637.

Disclosure of Interests

None declared

Differential genetic associations and expression of PAPST1/SLC35B2 in bipolar disorder and schizophrenia

Lithium's inhibitory effect on enzymes involved in sulfation process, such as inhibition of 3'(2')-phosphoadenosine 5'-phosphate (PAP) phosphatase, is a possible mechanism of its therapeutic effect for bipolar disorder (BD). 3'-Phosphoadenosine 5'-phosphosulfate (PAPS) is translocated from cytosol to Golgi lumen by PAPS transporter 1 (PAPST1/SLC35B2), where it acts as a sulfa donor. Since SLC35B2 was previously recognized as a molecule that facilitates the release of D-serine, a co-agonist of N-methyl-D-aspartate type glutamate receptor, altered function of SLC35B2 might be associated with the pathophysiology of BD and schizophrenia (SCZ). We performed genetic association analyses of the SLC35B2 gene using Japanese cohorts with 366 BD cases and 370 controls and 2012 SCZ cases and 2170 controls. We then investigated expression of SLC35B2 mRNA in postmortem brains by QPCR using a Caucasian cohort with 33 BD and 34 SCZ cases and 34 controls and by in situ hybridization using a Caucasian cohort with 37 SCZ and 29 controls. We found significant associations between three SNPs (rs575034, rs1875324, and rs3832441) and BD, and significantly reduced SLC35B2 mRNA expression in postmortem dorsolateral prefrontal cortex (DLPFC) of BD. Moreover, we observed normalized SLC35B2 mRNA expression in BD subgroups who were medicated with lithium. While there was a significant association of SLC35B2 with SCZ (SNP rs2233437), its expression was not changed in SCZ. These findings indicate that SLC35B2 might be differentially involved in the pathophysiology of BD and SCZ by influencing the sulfation process and/or glutamate system in the central nervous system.

Contribution of astrocytic histamine N-methyltransferase to histamine clearance and brain function in mice

Brain histamine acts as a neurotransmitter in the regulation of various brain activities. Previous studies have shown that histamine N-methyltransferase (HNMT), a histamine-metabolizing enzyme, controls brain histamine concentration and brain function. However, the relative contribution of astrocytic or neuronal HNMT to the regulation of the histaminergic system is still inconclusive. Here, we phenotyped astrocytes-specific HNMT knockout (cKO) mice to clarify the involvement of astrocytic HNMT in histamine clearance and brain function. First, we performed histological examinations using HNMT reporter mice and showed a wide distribution of HNMT in the brain and astrocytic HNMT expression. Then, we created cKO mice by Cre-loxP system and confirmed that HNMT expression in cKO primary astrocytes was robustly decreased. Although total HNMT level in the cortex was not substantially different between control and cKO brains, histamine concentration after histamine release was elevated in cKO cortex. In behavioral tests, impaired motor coordination and lower locomotor activity were observed in the cKO mice. However, anxiety-like behaviors, depression-like behaviors, and memory functions were not altered by astrocytic HNMT disruption. Although sleep analysis demonstrated that the quantity of wakefulness and sleep did not change, the increased power density of delta frequency during wakefulness indicated lower cortical activation in cKO mice. These results demonstrate that astrocytic HNMT contributes to histamine clearance after histamine release in the cortex and plays a role in the regulation of motor coordination, locomotor activity, and vigilance state.

Effects of C-factor on dentin bonding using various adhesive systems

Aims and Background

This study evaluated the effect of C-factor on the bond strength of a resin composite to floor and wall dentin using various adhesive systems.

Materials and Methods

Four dentin substrates (flat wall, flat floor, cavity wall, or cavity floor) were prepared on human molars. Each specimen was restored with one of three adhesives; Clearfil SE Bond, Single Bond, or Clearfil tri-S Bond followed by buildup or filling using Z100 resin composite. The specimen was cut perpendicular to the bonded surface parallel to the floor or wall to obtain beams after light curing at 24,000 mJ/cm². The microtensile bond strength to wall specimens or the cavity floor was determined. Data were analyzed.

Results

All adhesive systems exhibited the highest bond strength to flat wall group (p < 0.05). The bond strength to the cavity group was significantly lower than that to the respective flat group regardless of the bonding system (p < 0.05). There was no significant difference in bond strength with Clearfil SE Bond and Clearfil tri-S Bond between the cavity wall and cavity floor (p > 0.05).

Conclusion

The findings suggested that the strength of bonding to the cavity floor and cavity wall was affected by C-factor regardless of the adhesive system. Bonding to flat wall was higher than flat floor regardless of the adhesive system. Self-etching system provided uniform bond to the cavity wall and cavity floor dentin. However, total etching system reduced bond to the cavity floor than to the cavity wall.

Histamine and Microglia

Microglia, a category of glial cells in the central nervous system (CNS), have attracted much attention because of their important role in neuroinflammation. Many translational studies are currently ongoing to discover novel drugs targeting microglia for the treatment of various CNS disorders, such as Alzheimer's disease, Parkinson's disease (PD), and depression. Recent studies have shown that brain histamine, a neurotransmitter essential for the regulation of diverse brain functions, controls glial cells and neurons. In vitro studies using primary microglia and microglial cell lines have reported that histamine receptors are expressed in microglia and control microglial functions, including chemotaxis, migration, cytokine secretion, and autophagy. In vivo studies have demonstrated that histamine-related reagents could ameliorate abnormal symptoms in animal models of human diseases, such as amyotrophic lateral sclerosis (ALS), PD, and brain ischemia. Several human studies have revealed alterations in histamine receptor levels in ALS and PD, emphasizing the importance of the CNS histamine system, including histamine-dependent microglial modulation, as a therapeutic target for these disorders. In this review article, we summarize histamine-related research focusing on microglial functions.

[The development of online role-play for pharmacological education]

The role-play for pharmacological education has been developed by Yanagita et al. since 2010 and incorporated into the curriculum of more than 20 medical or pharmaceutical universities in Japan. This case and communication based active learning course provides the practice to acqire fundamental competences for drug therapy, through role playing of medical professionals and patients in simulated clinical settings. The online pharmacological role-play for the first time was performed at Tohoku Medical and Pharmaceutical University Faculty of Medicine during the state of emergency in Japan. We found that the online role-play was as useful as face-to-face role-plays to train appropriate drug prescriptions and communication skills in medical students. In this review, we described the course design, preparation, and operation of online role-play for pharmacological education. We also explained the differences, advantages, and disadvantages between online and face-to-face setting. Finally, we gave examples on-going challenges to the effective use of the online role-play as a core curricular model of pharmacological and pharmacotherapeutic education.

Validation of the HFA-PEFF and the H2FPEF scores for the diagnosis of heart failure with preserved ejection fraction in Japanese patients:a report from the Japanese multicentre registry

Background

The standard diagnosis of heart failure (HF) with preserved ejection fraction (HFpEF) is based on the following: 1) symptoms of HF, 2) preserved left ventricular (LV) ejection fraction (LVEF, &gt;50%), and 3) presence of LV diastolic dysfunction confirmed by echocardiography or cardiac catheterisation. However, there are limits to the diagnostic accuracy of individual parameters, and what cut-off values should be applied and how they should be combined remain unclear. Diagnostic algorithms for HFpEF such as the HFA-PEFF algorithm and the H2FPEF score have been proposed; however, previous validation studies were conducted in stable chronic HF and did not include an invasive haemodynamic assessment. Thus, the diagnostic accuracy for HFpEF lacked robustness. Moreover, information on their applicability in the Asian population is limited.

Purpose

The aim of this study was to investigate these scores' diagnostic validity for HFpEF in Japanese patients recently hospitalised due to acute decompensated HF.

Methods

We examined patients with HFpEF recently hospitalised with acute decompensated HF whose HFA-PEFF and H2FPEF scores could be calculated at discharge from a nationwide HFpEF-specific multicentre registry (HFpEF group) and control patients who underwent echocardiography to investigate the cause of dyspnoea in our hospital (Non-HFpEF group). We calculated the HFA-PEFF and the H2FPEF scores among the studied population. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were computed to compare the diagnostic accuracy of these scores.

Results

The studied population included 372 consecutive patients (194 HFpEF group and 178 Non-HFpEF group; HFpEF prevalence, 52%). The HFA-PEFF score classified 155 (42%) of all patients into the high likelihood category (5–6 points) and only 19 (5%) into the low likelihood category (0–1 point). A high HFA-PEFF score could diagnose HFpEF with a high specificity of 84% and a positive predictive value (PPV) of 82%, and a low HFA-PEFF score could rule out HFpEF with a high sensitivity of 99% and a negative predictive value (NPV) of 89%. The H2FPEF score classified 86 (23%) of all patients into the high likelihood category (6–9 points) and 84 (23%) into the low likelihood category (0–1 point). HFpEF could be diagnosed with a high H2FPEF score (specificity, 97%; PPV, 94%) or ruled out with a low H2FPEF score (sensitivity, 97%; NPV, 93%). The diagnostic accuracy for the HFA-PEFF and H2FPEF scores was 0.82 (95% confidence interval [CI] 0.78–0.86) and 0.89 (95% CI 0.86–0.93), respectively, by the AUC of the ROC curve (P=0.004) (Figure 1A). In the HFA-PEFF sub-scores, the functional score showed little diagnostic value, while the morphological and biomarker scores showed moderate diagnostic value (Figure 1B).

Conclusions

The H2FPEF score may be more useful than the HFA-PEFF score in diagnosing HFpEF in Japanese patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS KAKENHI) Figure 1

“Target Heart Rate” calculated aiming at zero overlap of mitral E and A waves is useful for prediction of long-term outcome for patients with heart failure and reduced ejection fraction

Background

Lower heart rate (HR) is associated with more favourable long-term outcome in patients with heart failure with reduced ejection fraction (HFrEF). However, an optimal threshold of HR remains unclear. Targeted HR (THR), defined by echocardiographic deceleration time (DCT) to eliminated overlap of E and A waves, may aid in risk stratification of HFrEF patients.

Purpose

In this study, we aimed to clarify the impact of on long-term clinical outcome in patients with HFrEF.

Methods

In the multicenter WET-HF registry, 4000 consecutive patients hospitalized for acute decompensated HF (ADHF) were registered between 2006 and 2017. Among them, the patients with EF ≥40% or a history of atrial fibrillation were excluded. THR was calculated based on their DCT value measured in compensated HF phase during the index admission. The following formula was applied; THR (bpm)=93 - 0.13 × deceleration time (DCT, msec). A total of 876 patients with HFrEF were included in the present analysis (age: 72 [60–81], male: 69%) and the patients were divided into the 2 groups of HR at discharge ≤ THR (L group) and &gt; THR (H group). The primary endpoint (PE) was defined as the composite of all-cause death and ADHF re-admission.

Results

Compared to the H group, the L group showed higher prevalence of males (74% vs. 66%, P=0.025) with higher body mass index (BMI, 23.2 vs. 22.2, P=0.016), hemoglobin (Hb, 12.9 vs. 12.4, P=0.031), albumin (Alb, 3.7 vs. 3.6, P=0.039) and larger left atrial diameter (LAD, 44 mm vs. 41 mm, P=0.002) and tricuspid regurgitation pressure gradient (TRPG, 29 mmHg vs. 27 mmHg, P=0.012). Age, estimated glomerular filtration rate (eGFR), LVEF (29% vs. 30%, P=NS) and E/e' (17.7 vs. 16.8, P=NS) were similar for both groups. At discharge, HR was lower in L group (66 [60–71] bpm vs. 80 [74–86] bpm, P&lt;0.001), albeit there were no significant differences in b-blocker prescription (90% vs. 85%, P=0.069) or its dose (3.75 [1.25–7.25] mg vs. 2.5 [1.25–5] mg, P=0.11).

In the survival analysis, the L group showed a significantly lower rate of PE (P=0.03), whereas there was no significant difference in the incidence of PE between the patients with HR at discharge ≥70 bpm and &lt;70 bpm (P=NS).

Multivariate Cox hazard analysis showed that HR at discharge ≤ THR was an independent predictor of PE (hazard ratio 0.67 [0.46–0.97], P=0.037), even after adjusting for confounding factors including age, sex, BMI, Hb, Alb, and b-blocker prescription, whereas HR at discharge &lt;70 bpm was not (hazard ratio 0.94 [0.65–1.33], P=0.71).

Conclusion

THR was associated with long-term outcomes in patients with HFrEF after acute decompensation, suggesting that it may aid in tailored treatment for HR reduction in these patients.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Efficacy and Safety of Non-brain Penetrating H1-Antihistamines for the Treatment of Allergic Diseases

H₁ receptor antagonists, known as H₁-antihistamines (AHs), inactivate the histamine H₁-receptor thereby preventing histamine causing the primary symptoms of allergic diseases, such as atopic dermatitis, pollinosis, food allergies, and urticaria. AHs, which are classified into first-generation (fgAHs) and second-generation (sgAHs) antihistamines, are the first line of treatment for allergic diseases. Although fgAHs are effective, they cause adverse reactions such as potent sedating effects, including drowsiness, lassitude, and cognitive impairment; anticholinergic effects, including thirst and tachycardia. Consequently, the use of fgAHs is not recommended for allergic diseases. Today, sgAHs, which are minimally sedating and, therefore, may be used at more effective doses, are the first-line treatment for alleviating the symptoms of allergic diseases. Pharmacologically, the use of sedating fgAHs is limited to antiemetics, anti-motion sickness drugs, and antivertigo drugs. The use of histamine H₁-receptor occupancy (H₁RO) based on positron emission tomography (PET) has been developed for the evaluation of brain penetrability. Based on the results of the H₁RO-PET studies, non-brain-penetrating AHs (nbpAHs) have recently been reclassified among sgAHs. The nbpAHs are rapidly acting and exhibit minimal adverse reactions and, thus, are considered first-line drugs for allergic diseases. In this review, we will introduce recent topics on the pharmacodynamics and pharmacokinetics of AHs and make recommendations for the use of nbpAHs as first-line treatment options for allergic diseases.

Chemogenetic modulation of histaminergic neurons in the tuberomamillary nucleus alters territorial aggression and wakefulness

Designer receptor activated by designer drugs (DREADDs) techniques are widely used to modulate the activities of specific neuronal populations during behavioural tasks. However, DREADDs-induced modulation of histaminergic neurons in the tuberomamillary nucleus (HA^TMN neurons) has produced inconsistent effects on the sleep–wake cycle, possibly due to the use of Hdc-Cre mice driving Cre recombinase and DREADDs activity outside the targeted region. Moreover, previous DREADDs studies have not examined locomotor activity and aggressive behaviours, which are also regulated by brain histamine levels. In the present study, we investigated the effects of HA^TMN activation and inhibition on the locomotor activity, aggressive behaviours and sleep–wake cycle of Hdc-Cre mice with minimal non-target expression of Cre-recombinase. Chemoactivation of HA^TMN moderately enhanced locomotor activity in a novel open field. Activation of HA^TMN neurons significantly enhanced aggressive behaviour in the resident–intruder test. Wakefulness was increased and non-rapid eye movement (NREM) sleep decreased for an hour by HA^TMN chemoactivation. Conversely HA^TMN chemoinhibition decreased wakefulness and increased NREM sleep for 6 h. These changes in wakefulness induced by HA^TMN modulation were related to the maintenance of vigilance state. These results indicate the influences of HA^TMN neurons on exploratory activity, territorial aggression, and wake maintenance.

Heparan sulfate promotes differentiation of white adipocytes to maintain insulin sensitivity and glucose homeostasis

Heparan sulfate (HS), a highly sulfated linear polysaccharide, is involved in diverse biological functions in various tissues. Although previous studies have suggested a possible contribution of HS to the differentiation of white adipocytes, there has been no direct evidence supporting this. Here, we inhibited the synthesis of HS chains in 3T3-L1 cells using CRISPR–Cas9 technology, resulting in impaired differentiation of adipocytes with attenuated bone morphogenetic protein 4 (BMP4)–fibroblast growth factor 1 (FGF1) signaling pathways. HS reduction resulted in reduced glucose uptake and decreased insulin-dependent intracellular signaling. We then made heterozygous mutant mice for the Ext1 gene, which encodes an enzyme essential for the HS biosynthesis, specifically in the visceral white adipose tissue (Fabp4-Cre⁺::Ext1^flox/WT mice, hereafter called Ext1^Δ/WT) to confirm the importance of HS in vivo. The expression levels of transcription factors that control adipocyte differentiation, such as peroxisome proliferator–activated receptor gamma, were reduced in Ext1^Δ/WT adipocytes, which contained smaller, unilocular lipid droplets, reduced levels of enzymes involved in lipid synthesis, and altered expression of BMP4–FGF1 signaling molecules. Furthermore, we examined the impact of HS reduction in visceral white adipose tissue on systemic glucose homeostasis. We observed that Ext1^Δ/WT mice showed glucose intolerance because of insulin resistance. Our results demonstrate that HS plays a crucial role in the differentiation of white adipocytes through BMP4–FGF1 signaling pathways, thereby contributing to insulin sensitivity and glucose homeostasis.

AB0311 INCREASED LEVELS OF SERUM WISTERIA FLORIBUNDA AGGLUTININPOSITIVE MAC-2 BINDING PROTEIN IN RHEUMATIC DISEASES INCLUDING SLE

Background:

Mac-2 binding protein is a cell-adhesive glycoprotein of the extracellular matrix secreted as a ligand of galectin-3 (Mac-2). Recently, a Wisteria floribunda agglutinin positive-M2BP (M2BP) assay developed using a lectin-antibody sandwich immunoassay has shown promise as a new fibrotic marker in liver fibrosis and interstitial lung disease (ILD) to detect unique fibrosis-related glycoalteration.

Objectives:

The aim of this study is to evaluate the utility of serum Mac-2 binding protein glycosylation isomer (M2BPGi) levels in patients with rheumatic diseases (RD).

Methods:

We retrospectively measured serum M2BPGi levels in 68 patients with RD and 16 healthy controls (HC). There were no patients of cirrhosis and active hepatitis. Serum levels of M2BPGi were measured using HISCL M2BP glycosylation isomer Assay Kit. We examined the relationship between serum M2BPGi levels and clinical parameters in patients with RD.

Results:

In patients with RD, the median age was 62.0 years and 79.4% of them were female.

Serum M2BPGi levels were significantly higher in patients with RD than in HC (median 0.98 cutoff index [COI], 0.32 COI, respectively; P < 0.00001). Patients with SLE tended to have higher serum M2BPGi levels than other rheumatic diseases.

In patients with RD, a significant correlation was not found between serum M2BP levels and inflammation markers such as CRP or ferritin. However, serum M2BPGi levels were significantly correlated with B cell activation markers such as immunoglobulin free light chain and IgG (r = 0.588, 0.504) and T cell activation marker such as sIL-2R (r = 0.408).

Conclusion:

Most of the rheumatic diseases in this study were considered to be type I interferonopathy diseases such as rheumatoid arthritis, Sjogren’s syndrome, inflammatory myositis, scleroderma and SLE.

Serum M2BPGi was reported to have a significant correlation with SLE disease activity [SS Ahn et al. Lupus. 2018; 27: 771], and also to have a significant correlation with Gakectin-9, a novel biomarker for IFN signiture [Lucas L van den Hoogen et al. Ann Rheum Dis. 2018; 77: 1810].

So, it was suggested that serum M2BPGi may be a novel biomarker that indirectly indicates how much IFN is activated in rheumatic diseases.

Disclosure of Interests:

None declared

Genetic risks of schizophrenia identified in a matched case-control study

It has been suggested that dopaminergic neurotransmission plays important roles for the psychotic symptoms and probably etiology of schizophrenia. In our recent preliminary study, we demonstrated that the specific allele combinations of dopamine-related functional single nucleotide polymorphisms (SNPs), rs10770141, rs4680, and rs1800497 could indicate risks for schizophrenia. The present validation study involved a total of 2542 individuals who were age- and sex-matched in a propensity score matching analysis, and the results supported the statistical significances of the proposed genetic risks described in our previous reports. The estimated odds ratios were 1.24 (95% CI 1.06-1.45, p < 0.001) for rs4680, 1.73 (95% CI 1.47-2.02, p < 0.0001) for rs1800497, and 1.79 (95% CI 1.35-2.36, p < 0.0001) for rs10770141. A significant relationship was also revealed among these three polymorphisms and schizophrenia, with corresponding coefficients (p < 0.0001). In this study, we also present a new scoring model for the identification of individuals with the disease risks. Using the cut-off value of 2, our model exhibited sensitivity for almost two-thirds of all of the schizophrenia patients: odds ratio 1.87, 95% CI 1.59-2.19, p < 0.0001. In conclusion, we identified significant associations of dopamine-related genetic combinations with schizophrenia. These findings suggest that some types of dopaminergic neurotransmission play important roles for development of schizophrenia, and this type of approach may also be applicable for other multifactorial diseases, providing a potent new risk predictor.

Glyoxalase I disruption and external carbonyl stress impair mitochondrial function in human induced pluripotent stem cells and derived neurons

Carbonyl stress, a specific form of oxidative stress, is reported to be involved in the pathophysiology of schizophrenia; however, little is known regarding the underlying mechanism. Here, we found that disruption of GLO1, the gene encoding a major catabolic enzyme scavenging the carbonyl group, increases vulnerability to external carbonyl stress, leading to abnormal phenotypes in human induced pluripotent stem cells (hiPSCs). The viability of GLO1 knockout (KO)-hiPSCs decreased and activity of caspase-3 was increased upon addition of methylglyoxal (MGO), a reactive carbonyl compound. In the GLO1 KO-hiPSC-derived neurons, MGO administration impaired neurite extension and cell migration. Further, accumulation of methylglyoxal-derived hydroimidazolone (MG-H1; a derivative of MGO)-modified proteins was detected in isolated mitochondria. Mitochondrial dysfunction, including diminished membrane potential and dampened respiratory function, was observed in the GLO1 KO-hiPSCs and derived neurons after addition of MGO and hence might be the mechanism underlying the effects of carbonyl stress. The susceptibility to MGO was partially rescued by the administration of pyridoxamine, a carbonyl scavenger. Our observations can be used for designing an intervention strategy for diseases, particularly those induced by enhanced carbonyl stress or oxidative stress.

Lymph node dissection for gastric cancer: Establishment of D2 and the current position of splenectomy in Europe and Japan

Two European phase III trials comparing D1 and D2 demonstrated that D2 did not improve the overall survival and was associated with a high mortality related to splenectomy. However, a long-term follow-up study showed that the gastric cancer-related death rate was significantly higher in D1 than D2. Based on these findings, the standard surgery in Europe became D2 without pancreatico-splenectomy to prevent mortality. In contrast, the JCOG9501 phase III comparing D2 and D2 plus para-aortic nodal dissection did not showed a survival efficacy of extended lymphadenectomy, but the mortality rate was quite low in both surgeries. Subsequently, the JCOG0110 phase III study comparing D2 and spleen-preserving D2 for upper gastric cancer not invading the greater curvature clearly showed the non-inferiority of spleen preservation. Thus, spleen-preserving D2 was made the standard surgery for these tumors in Japan. However, splenectomy is often selected for complete dissection of the splenic-hilar nodes, a frequent metastatic site for upper gastric tumors invading the greater curvature. Recently, an approach involving splenic hilar nodal dissection without splenectomy has been developed.

Cooperation of LIM domain-binding 2 (LDB2) with EGR in the pathogenesis of schizophrenia

Genomic defects with large effect size can help elucidate unknown pathologic architecture of mental disorders. We previously reported on a patient with schizophrenia and a balanced translocation between chromosomes 4 and 13 and found that the breakpoint within chromosome 4 is located near the LDB2 gene. We show here that Ldb2 knockout (KO) mice displayed multiple deficits relevant to mental disorders. In particular, Ldb2 KO mice exhibited deficits in the fear-conditioning paradigm. Analysis of the amygdala suggested that dysregulation of synaptic activities controlled by the immediate early gene Arc is involved in the phenotypes. We show that LDB2 forms protein complexes with known transcription factors. Consistently, ChIP-seq analyses indicated that LDB2 binds to > 10,000 genomic sites in human neurospheres. We found that many of those sites, including the promoter region of ARC, are occupied by EGR transcription factors. Our previous study showed an association of the EGR family genes with schizophrenia. Collectively, the findings suggest that dysregulation in the gene expression controlled by the LDB2-EGR axis underlies a pathogenesis of subset of mental disorders.

Potential involvement of DSCAML1 mutations in neurodevelopmental disorders

The molecular mechanisms underlying neurodevelopmental disorders (NDDs) remain unclear. We previously identified Down syndrome cell adhesion molecule like 1 (Dscaml1) as a responsible gene for Ihara epileptic rat (IER), a rat model for human NDDs with epilepsy. However, the relationship between NDDs and DSCAML1 in humans is still elusive. In this study, we screened databases of autism spectrum disorders (ASD), intellectual disability (ID)/developmental disorders (DD) and schizophrenia for genomic mutations in human DSCAML1. We then performed in silico analyses to estimate the potential damage to the mutated DSCAML1 proteins and chose three representative mutations (DSCAML1C729R , DSCAML1R1685* and DSCAML1K2108Nfs*37 ), which lacked a cysteine residue in the seventh Ig domain, the intracellular region and the C-terminal PDZ-binding motif, respectively. In overexpression experiments in a cell line, DSCAML1C729R lost its mature N-glycosylation, whereas DSCAML1K2108Nfs*37 was abnormally degraded via proteasome-dependent protein degradation. Furthermore, in primary hippocampal neurons, the ability of the wild-type DSCAML1 to regulate the number of synapses was lost with all mutant proteins. These results provide insight into understanding the roles of the domains in the DSCAML1 protein and further suggest that these mutations cause functional changes, albeit through different mechanisms, that likely affect the pathophysiology of NDDs.

Role of an Atypical Cadherin Gene, Cdh23 in Prepulse Inhibition, and Implication of CDH23 in Schizophrenia

We previously identified quantitative trait loci (QTL) for prepulse inhibition (PPI), an endophenotype of schizophrenia, on mouse chromosome 10 and reported Fabp7 as a candidate gene from an analysis of F2 mice from inbred strains with high (C57BL/6N; B6) and low (C3H/HeN; C3H) PPI levels. Here, we reanalyzed the previously reported QTLs with increased marker density. The highest logarithm of odds score (26.66) peaked at a synonymous coding and splice-site variant, c.753G>A (rs257098870), in the Cdh23 gene on chromosome 10; the c.753G (C3H) allele showed a PPI-lowering effect. Bayesian multiple QTL mapping also supported the same variant with a posterior probability of 1. Thus, we engineered the c.753G (C3H) allele into the B6 genetic background, which led to dampened PPI. We also revealed an e-QTL (expression QTL) effect imparted by the c.753G>A variant for the Cdh23 expression in the brain. In a human study, a homologous variant (c.753G>A; rs769896655) in CDH23 showed a nominally significant enrichment in individuals with schizophrenia. We also identified multiple potentially deleterious CDH23 variants in individuals with schizophrenia. Collectively, the present study reveals a PPI-regulating Cdh23 variant and a possible contribution of CDH23 to schizophrenia susceptibility.

Organic Cation Transporters in Brain Histamine Clearance: Physiological and Psychiatric Implications

Histamine acts as a neurotransmitter in the central nervous system and is involved in numerous physiological functions. Recent studies have identified the causative role of decreased histaminergic systems in various neurological disorders. Thus, the brain histamine system has attracted attention as a therapeutic target to improve brain function. Neurotransmitter clearance is one of the most important processes for the regulation of neuronal activity and is an essential target for diverse drugs. Our previous study has shown the importance of histamine N-methyltransferase for the inactivation of brain histamine and the intracellular localization of this enzyme; the study indicated that the transport system for the movement of positively charged histamine from the extracellular to intracellular space is a prerequisite for histamine inactivation. Several studies on in vitro astrocytic histamine transport have indicated the contribution of organic cation transporter 3 (OCT3) and plasma membrane monoamine transporter (PMAT) in histamine uptake, although the importance of these transporters in in vivo histamine clearance remains unknown. Immunohistochemical analyses have revealed the expression of OCT3 and PMAT on neurons, emphasizing the importance of investigating neuronal histamine uptake. Further studies using knockout mice or fast-scan cyclic voltammetry will accelerate the research on histamine transporters. In this review article, we summarize histamine transport assays and describe the candidate transporters responsible for histamine transport in the brain.