Identifying prognostic biomarkers for palbociclib add-on therapy in fulvestrant-resistant breast cancer using cell-free DNA sequencing

BACKGROUND

The FUTURE trial (UMIN000029294) demonstrated the safety and efficacy of adding palbociclib after fulvestrant resistance in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced and metastatic breast cancer (ABC/MBC). In this planned sub-study, cancer panel sequencing of cell-free DNA (cfDNA) was utilized to explore prognostic and predictive biomarkers for further palbociclib treatment following fulvestrant resistance.

MATERIALS AND METHODS

Herein, 149 cfDNA samples from 65 patients with fulvestrant-resistant disease were analysed at the time of palbociclib addition after fulvestrant resistance (baseline), on day 15 of cycle 1, and at the end of treatment using the assay for identifying diverse mutations in 34 cancer-related genes.

RESULTS

During the course of treatment, mutations in ESR1, PIK3CA, FOXA1, RUNX1, TBX3, and TP53 were the most common genomic alterations observed. Analysis of genomic mutations revealed that before fulvestrant introduction, baseline PIK3CA mutations were marginally lower in metastatic aromatase inhibitor (AI)-treated patients compared to adjuvant AI-treated patients (P = 0.063). Baseline PIK3CA mutations were associated with poorer progression-free survival [hazard ratio: 1.62, P = 0.04]. Comparative analysis between baseline and early-changing gene mutations identified poor prognostic factors including early-changing MAP3K1 mutations (hazard ratio: 4.66, P = 0.04), baseline AR mutations (hazard ratio: 3.53, P = 0.04), and baseline PIK3CA mutations (hazard ratio: 3.41, P = 0.02). Notably, the relationship between ESR1 mutations and mutations in PIK3CA, MAP3K1, and TP53 weakened as treatment progressed. Instead, PIK3CA mutations became correlated with TP53 and FOXA1 mutations.

CONCLUSIONS

Cancer panel testing for cfDNA identified prognostic and predictive biomarkers for palbociclib add-on therapy after acquiring fulvestrant resistance in patients with HR+/HER2- ABC/MBC.

Mitotic Spindle Positioning (MISP) Facilitates Colorectal Cancer Progression by Forming a Complex with Opa Interacting Protein 5 (OIP5) and Activating the JAK2-STAT3 Signaling Pathway

Patients with inflammatory bowel disease (IBD) who experience long-term chronic inflammation of the colon are at an increased risk of developing colorectal cancer (CRC). Mitotic spindle positioning (MISP), an actin-binding protein, plays a role in mitosis and spindle positioning. MISP is found on the apical membrane of the intestinal mucosa and helps stabilize and elongate microvilli, offering protection against colitis. This study explored the role of MISP in colorectal tumorigenesis using a database, human CRC cells, and a mouse model for colitis-induced colorectal tumors triggered by azoxymethane (AOM)/dextran sodium sulfate (DSS) treatment. We found that MISP was highly expressed in colon cancer patient tissues and that reduced MISP expression inhibited cell proliferation. Notably, MISP-deficient mice showed reduced colon tumor formation in the AOM/DSS-induced colitis model. Furthermore, MISP was found to form a complex with Opa interacting protein 5 (OIP5) in the cytoplasm, influencing the expression of OIP5 in a unidirectional manner. We also observed that MISP increased the levels of phosphorylated STAT3 in the JAK2-STAT3 signaling pathway, which is linked to tumorigenesis. These findings indicate that MISP could be a risk factor for CRC, and targeting MISP might provide insights into the mechanisms of colitis-induced colorectal tumorigenesis.

The neutrophil-osteogenic cell axis promotes bone destruction in periodontitis

The immune-stromal cell interactions play a key role in health and diseases. In periodontitis, the most prevalent infectious disease in humans, immune cells accumulate in the oral mucosa and promote bone destruction by inducing receptor activator of nuclear factor-κB ligand (RANKL) expression in osteogenic cells such as osteoblasts and periodontal ligament cells. However, the detailed mechanism underlying immune-bone cell interactions in periodontitis is not fully understood. Here, we performed single-cell RNA-sequencing analysis on mouse periodontal lesions and showed that neutrophil-osteogenic cell crosstalk is involved in periodontitis-induced bone loss. The periodontal lesions displayed marked infiltration of neutrophils, and in silico analyses suggested that the neutrophils interacted with osteogenic cells through cytokine production. Among the cytokines expressed in the periodontal neutrophils, oncostatin M (OSM) potently induced RANKL expression in the primary osteoblasts, and deletion of the OSM receptor in osteogenic cells significantly ameliorated periodontitis-induced bone loss. Epigenomic data analyses identified the OSM-regulated RANKL enhancer region in osteogenic cells, and mice lacking this enhancer showed decreased periodontal bone loss while maintaining physiological bone metabolism. These findings shed light on the role of neutrophils in bone regulation during bacterial infection, highlighting the novel mechanism underlying osteoimmune crosstalk.

IGLL5 controlled by super-enhancer affects cell survival and MYC expression in mature B-cell lymphoma

IGLL5 is shown to be located near super-enhancer (SE) in B-cell tumors, and this gene is frequently mutated and a target of translocation in B-cell tumors. These results suggest roles of the IGLL5 in tumorigenesis; however, its functional properties have been unclear. We found that two mature B-cell lymphoma cell lines expressed IGLL5 mRNA with Cλ1 segment. JQ1 treatment resulted in down-expression of IGLL5, indicating that IGLL5 is controlled by SE. IGLL5 knockdown induced cell death with down-expression of MYC. Our results suggested that IGLL5 might have a role in survival of mature B-cell tumors and involvement in MYC expression. (100 words).

[Veno-venous extracorporeal membrane oxygenation for capillary leak syndrome during induction chemotherapy in acute myeloid leukemia]

A 44-year-old woman was diagnosed with acute myeloid leukemia (RUNX1::RUNX1T1 translocation) and received induction chemotherapy with idarubicin hydrochloride and cytosine arabinoside. The pneumonia that had been present since admission worsened, and a drug-induced skin rash appeared. On day 17, she presented with respiratory failure and shock, complicated by hemoconcentration and hypoalbuminemia. This was considered capillary leak syndrome due to pneumonia and drug allergy, so she was started on pulse steroid therapy and IVIG, and was intubated on the same day. On day 18, venovenous-extracorporeal membrane oxygenation (VV-ECMO) was started due to worsening blood gas parameters despite ventilatory management. Bronchoalveolar lavage fluid was serous, and both blood and sputum cultures yielded negative. The patient was weaned from VV-ECMO on day 26 as the pneumonia improved with recovery of hematopoiesis. She was disoriented, and a CT scan on day 28 revealed cerebral hemorrhage. Her strength recovered with rehabilitation. After induction chemotherapy, RUNX1::RUNX1T1 mRNA was not detected in bone marrow. The patient received consolidation chemotherapy, and has maintained complete remission. Severe respiratory failure during induction chemotherapy for acute leukemia can be fatal, but VV-ECMO may be lifesaving.

Comparison of the outcomes of patients with primary central nervous system lymphoma between the neurosurgery and hematology/oncology departments based on the relative dose intensity of methotrexate

Primary central nervous system lymphoma (PCNSL) is an extranodal type of lymphoma, which is treated with methotrexate (MTX)-based induction therapy. Although PCNSL is a hematological malignancy, patients with PCNSL may be treated at neurosurgery or hematology/oncology departments; however, the outcomes of PCNSL treatment have not been compared between these two departments. The present study compared the outcomes of 26 patients with newly diagnosed PCNSL that were treated at the Department of Neurological Surgery or Department of Hematology/Oncology (Wakayama Medical University Hospital, Wakayama, Japan) between January 2011 and December 2021. The relative dose intensity (RDI) and relative treatment intensity of MTX were assessed as indicators of the intensity of chemotherapy. The median RDI of MTX was 67 and 93% in the neurosurgery and hematology/oncology groups, respectively (P<0.001). The proportion of patients that achieved a complete response after high-dose MTX-based therapy was significantly higher in the hematology/oncology group than in the neurosurgery group (P=0.038). The estimated 2-year overall survival was 72 and 100% in the neurosurgery and hematology/oncology groups, respectively (P=0.046). As with the difference in the outcomes observed between pediatrics and hematology departments for adolescents with acute lymphoblastic leukemia, the outcomes of patients with PCNSL may differ between neurosurgery and hematology/oncology departments.

Predicting habitual water intake from lifestyle questions

OBJECTIVE

Previous studies have used selective recall and descriptive dietary record methods, requiring considerable effort for assessing food and water intake. This study created a simplified lifestyle questionnaire to predict habitual water intake (SQW), accurately and quickly assessing the habitual water intake. We also evaluated the validity using descriptive dietary records as a cross-sectional study.

SUBJECTS AND METHODS

First, we used crowdsourcing and machine learning to collect data, predict water intake records, and create questionnaires. We collected 305 lifestyle-related questions as predictor variables and selective recall methods for assessing water intake as an outcome variable. Random forests were used for the machine learning models because of their interpretability and accurate estimation. Random forest and single regression correlation analysis were augmented by the synthetic minority oversampling that trained the model. We separated the data by sex and evaluated our model using unseen hold-out testing data, predicting the individual and overall habitual water intake from various sources, including non-alcoholic beverages, alcohol, and food.

RESULTS

We found a 0.60 Spearman's correlation coefficient for total water intake between the predicted and the selective recall method values, reflecting the target value to be achieved. This question set was then used for feasibility tests. The descriptive dietary record method helped to obtain a ground-truth value. We categorized the data by gender, season, and source: non-alcoholic beverages, alcohol, food, and total water intake, and the correlation was confirmed. Consequently, our results showed a Pearson's correlation coefficient of 0.50 for total water intake between the predicted and the selective recall method values.

CONCLUSIONS

We hypothesize that dissemination of SQW can lead to better health management by easily determining the habitual water intake.

Identification of an intronic enhancer regulating RANKL expression in osteocytic cells

The bony skeleton is continuously renewed throughout adult life by the bone remodeling process, in which old or damaged bone is removed by osteoclasts via largely unknown mechanisms. Osteocytes regulate bone remodeling by producing the osteoclast differentiation factor RANKL (encoded by the TNFSF11 gene). However, the precise mechanisms underlying RANKL expression in osteocytes are still elusive. Here, we explored the epigenomic landscape of osteocytic cells and identified a hitherto-undescribed osteocytic cell-specific intronic enhancer in the TNFSF11 gene locus. Bioinformatics analyses showed that transcription factors involved in cell death and senescence act on this intronic enhancer region. Single-cell transcriptomic data analysis demonstrated that cell death signaling increased RANKL expression in osteocytic cells. Genetic deletion of the intronic enhancer led to a high-bone-mass phenotype with decreased levels of RANKL in osteocytic cells and osteoclastogenesis in the adult stage, while RANKL expression was not affected in osteoblasts or lymphocytes. These data suggest that osteocytes may utilize a specialized regulatory element to facilitate osteoclast formation at the bone surface to be resorbed by linking signals from cellular senescence/death and RANKL expression.

Susceptibility to adriamycin-induced hepatotoxicity in mice depends on PRKDC polymorphism

Adriamycin (ADR) is an effective chemotherapy drug for various cancers but has serious side effects. ADR-induced liver damage is a common problem during therapy, but the underlying mechanism remains to be fully understood. In contrast, ADR-induced glomerular damage is well studied in rodents, and sensitivity to ADR-induced nephropathy is because of the R2140C polymorphism of Prkdc gene. To investigate whether strain differences or sensitivity to ADR-induced liver damage are related to Prkdc polymorphism, this study compared the sensitivity to ADR-induced liver damage among C57BL/6J (B6J), B6-Prkdc^R2140C, and BALB/c mice. Although B6J exhibits resistance to ADR-induced liver injury, BALB/c and B6-Prkdc^R2140C are more susceptible to liver injury, which is exacerbated by the presence of R2140C mutation in PRKDC.

Dietary omega-3 fatty acid does not improve male infertility caused by lysophospholipid acyltransferase 3 (LPLAT3/AGPAT3) deficiency

Docosahexaenoic acid (DHA), an omega-3 fatty acid, usually presents as a constituent of phospholipids in the cellular membrane. Lysophospholipid acyltransferase 3 (LPLAT3; AGPAT3) is the primary enzyme that incorporates DHA into phospholipids. LPLAT3-KO mice show male infertility and visual dysfunction accompanied by decreased phospholipids (PLs) containing DHA (PL-DHA) in the testis and retina, respectively. In this study, we evaluated the effect of diets consisting mainly of triacylglycerol-bound DHA (fish oil) and PL-bound DHA (salmon roe oil) on the amount of PL-DHA in a broad range of tissues and on reproductive functions. Both diets elevated phosphatidylcholines (PCs)-containing DHA in most tissues of wild type (WT) mice. Although LPLAT3-KO mice acquired a minimal amount of PC-DHA in the testes and sperm by eating either of the diets, reproductive function did not improve. The present study suggests that DHA-rich diets do not restore sufficient PL-DHA to improve male infertility in LPLAT3-KO mice. Alternatively, PL-DHA can be biosynthesized by LPLAT3 but not by external supplementation, which may be necessary for normal reproductive function.

Mice lacking nucleotide sugar transporter SLC35A3 exhibit lethal chondrodysplasia with vertebral anomalies and impaired glycosaminoglycan biosynthesis

SLC35A3 is considered an uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) transporter in mammals and regulates the branching of N-glycans. A missense mutation in SLC35A3 causes complex vertebral malformation (CVM) in cattle. However, the biological functions of SLC35A3 have not been fully clarified. To address these issues, we have established Slc35a3-/-mice using CRISPR/Cas9 genome editing system. The generated mutant mice were perinatal lethal and exhibited chondrodysplasia recapitulating CVM-like vertebral anomalies. During embryogenesis, Slc35a3 mRNA was expressed in the presomitic mesoderm of wild-type mice, suggesting that SLC35A3 transports UDP-GlcNAc used for the sugar modification that is essential for somite formation. In the growth plate cartilage of Slc35a3-/-embryos, extracellular space was drastically reduced, and many flat proliferative chondrocytes were reshaped. Proliferation, apoptosis and differentiation were not affected in the chondrocytes of Slc35a3-/-mice, suggesting that the chondrodysplasia phenotypes were mainly caused by the abnormal extracellular matrix quality. Because these histological abnormalities were similar to those observed in several mutant mice accompanying the impaired glycosaminoglycan (GAG) biosynthesis, GAG levels were measured in the spine and limbs of Slc35a3-/-mice using disaccharide composition analysis. Compared with control mice, the amounts of heparan sulfate, keratan sulfate, and chondroitin sulfate/dermatan sulfate, were significantly decreased in Slc35a3-/-mice. These findings suggest that SLC35A3 regulates GAG biosynthesis and the chondrodysplasia phenotypes were partially caused by the decreased GAG synthesis. Hence, Slc35a3-/- mice would be a useful model for investigating the in vivo roles of SLC35A3 and the pathological mechanisms of SLC35A3-associated diseases.

Molecular and Pathological Analyses of IARS1-Deficient Mice: An IARS Disorder Model

Most mitochondrial diseases are hereditary and highly heterogeneous. Cattle born with the V79L mutation in the isoleucyl-tRNA synthetase 1 (IARS1) protein exhibit weak calf syndrome. Recent human genomic studies about pediatric mitochondrial diseases also identified mutations in the IARS1 gene. Although severe prenatal-onset growth retardation and infantile hepatopathy have been reported in such patients, the relationship between IARS mutations and the symptoms is unknown. In this study, we generated hypomorphic IARS1^V79L mutant mice to develop an animal model of IARS mutation-related disorders. We found that compared to wild-type mice, IARS^V79L mutant mice showed a significant increase in hepatic triglyceride and serum ornithine carbamoyltransferase levels, indicating that IARS1^V79L mice suffer from mitochondrial hepatopathy. In addition, siRNA knockdown of the IARS1 gene decreased mitochondrial membrane potential and increased reactive oxygen species in the hepatocarcinoma-derived cell line HepG2. Furthermore, proteomic analysis revealed decreased levels of the mitochondrial function-associated protein NME4 (mitochondrial nucleoside diphosphate kinase). Concisely, our mutant mice model can be used to study IARS mutation-related disorders.

Ameliorated Renal Pathological Feature in MRL/MpJ-Faslpr/lpr Background Interleukin-36 Receptor-Deficient Mice

Systemic autoimmune diseases frequently induce lupus nephritis, causing altered balance and expression of interleukin 36 receptor (IL-36R) ligands, including agonists (IL-36α, β, γ) and antagonists (IL-36Ra, IL-38), in kidneys. Here, we established and analyzed a mouse model of lupus nephritis, MRL/MpJ-Faslpr/lpr with IL-36R-knockout (KO), compared to wild-type (WT) mice. In both genotypes, indices for immune abnormalities and renal functions were comparable, although female WT mice showed higher serum autoantibody levels than males. IL-36R ligand expression did not differ significantly between genotypes at the mRNA level or in IL-36α and IL-38 scores. However, glomerular lesions, especially mesangial matrix expansion, were significantly ameliorated in both sexes of IL-36R-KO mice compared to WT mice. Cell infiltration into the tubulointerstitium with the development of tertiary lymphoid structures was comparable between genotypes. However, the positive correlation with the IL-36α score in WT mice was not evident in IL-36R-KO mice. Fibrosis was less in female IL-36R-KO mice than in WT mice. Importantly, some IL-36α+ nuclei co-localized with acetylated lysine and GCN5 histone acetyltransferase, in both genotypes. Therefore, IL-36R ligands, especially IL-36α, contribute to the progression of renal pathology in lupus nephritis via IL-36R-dependent and IL-36R-independent pathways.

Mesenchymal loss of p53 alters stem cell capacity and models human soft tissue sarcoma traits

Soft tissue sarcomas (STSs) are a heterogeneous group of tumors that originate from mesenchymal cells. p53 is frequently mutated in human STS. In this study, we found that the loss of p53 in mesenchymal stem cells (MSCs) mainly causes adult undifferentiated soft tissue sarcoma (USTS). MSCs lacking p53 show changes in stem cell properties, including differentiation, cell cycle progression, and metabolism. The transcriptomic changes and genetic mutations in murine p53-deficient USTS mimic those seen in human STS. Furthermore, single-cell RNA sequencing revealed that MSCs undergo transcriptomic alterations with aging-a risk factor for certain types of USTS-and that p53 signaling decreases simultaneously. Moreover, we found that human STS can be transcriptomically classified into six clusters with different prognoses, different from the current histopathological classification. This study paves the way for understanding MSC-mediated tumorigenesis and provides an efficient mouse model for sarcoma studies.

Robust protein-based engineering of hepatocyte-like cells from human mesenchymal stem cells

BACKGROUND

Cells of interest can be prepared from somatic cells by forced expression of lineage-specific transcription factors, but it is required to establish a vector-free system for their clinical use. Here, we report a protein-based artificial transcription system for engineering hepatocyte-like cells from human umbilical cord-derived mesenchymal stem cells (MSCs).

METHODS

MSCs were treated for 5 days with 4 artificial transcription factors (4F), which targeted hepatocyte nuclear factor (HNF)1α, HNF3γ, HNF4α, and GATA-binding protein 4 (GATA4). Then, engineered MSCs (4F-Heps) were subjected to epigenetic analysis, biochemical analysis and flow cytometry analysis with antibodies to marker proteins of mature hepatocytes and hepatic progenitors such as delta-like homolog 1 (DLK1) and trophoblast cell surface antigen 2 (TROP2). Functional properties of the cells were also examined by injecting them to mice with lethal hepatic failure.

RESULTS

Epigenetic analysis revealed that a 5-day treatment of 4F upregulated the expression of genes involved in hepatic differentiation, and repressed genes related to pluripotency of MSCs. Flow cytometry analysis detected that 4F-Heps were composed of small numbers of mature hepatocytes (at most 1%), bile duct cells (~19%) and hepatic progenitors (~50%). Interestingly, ~20% of 4F-Heps were positive for cytochrome P450 3A4, 80% of which were DLK1-positive. Injection of 4F-Heps significantly increased survival of mice with lethal hepatic failure, and transplanted 4F-Heps expanded to more than 50-fold of human albumin-positive cells in the mouse livers, well consistent with the observation that 4F-Heps contained DLK1-positive and/or TROP2-positive cells.

CONCLUSION

Taken together with observations that 4F-Heps were not tumorigenic in immunocompromised mice for at least 2 years, we propose that this artificial transcription system is a versatile tool for cell therapy for hepatic failures.

Identification of SARS-CoV-2 Mpro inhibitors containing P1' 4-fluorobenzothiazole moiety highly active against SARS-CoV-2

COVID-19 caused by SARS-CoV-2 has continually been serious threat to public health worldwide. While a few anti-SARS-CoV-2 therapeutics are currently available, their antiviral potency is not sufficient. Here, we identify two orally available 4-fluoro-benzothiazole-containing small molecules, TKB245 and TKB248, which specifically inhibit the enzymatic activity of main protease (M^pro) of SARS-CoV-2 and significantly more potently block the infectivity and replication of various SARS-CoV-2 strains than nirmatrelvir, molnupiravir, and ensitrelvir in cell-based assays employing various target cells. Both compounds also block the replication of Delta and Omicron variants in human-ACE2-knocked-in mice. Native mass spectrometric analysis reveals that both compounds bind to dimer M^pro, apparently promoting M^pro dimerization. X-ray crystallographic analysis shows that both compounds bind to M^pro's active-site cavity, forming a covalent bond with the catalytic amino acid Cys-145 with the 4-fluorine of the benzothiazole moiety pointed to solvent. The data suggest that TKB245 and TKB248 might serve as potential therapeutics for COVID-19 and shed light upon further optimization to develop more potent and safer anti-SARS-CoV-2 therapeutics.

Genetic background strongly influences the transition to chronic kidney disease of adriamycin nephropathy in mice

Animal models of podocytopathy and chronic kidney diseases (CKD) help elucidate these pathologies. Adriamycin (ADR)-induced nephropathy is a common rodent model of podocytopathy. BALB/c mice are sensitive to ADR, whereas C57BL/6 (B6) mice, the most commonly used strain, are resistant to ADR. Therefore, mouse strains with the B6 genetic background cannot be used as an ADR nephropathy model. We previously generated DNA-dependent protein kinase catalytic subunit (Prkdc) mutant B6 mice (B6-Prkdc^R2140C) carrying the R2140C mutation that causes ADR nephropathy. However, whether ADR nephropathy in the novel strain progresses to CKD after ADR administration has not been evaluated. Therefore, we examined whether the B6-Prkdc^R2140C mice develop CKD after ADR administration. We also evaluated whether differences existed in the genetic background in ADR nephropathy by comparing the B6-Prkdc^R2140C mice with BALB/c mice. Our findings demonstrated that B6-Prkdc^R2140C progresses to CKD and is resistant to nephropathy compared with the BALB/c mice. The B6-Prkdc^R2140C and BALB/c mice differed in the expression of genes related to inflammatory mediators, and further analysis is required to identify factors that contribute to resistance to nephropathy.

A protein kinase D inhibitor suppresses AKT on T cells and antagonizes cancer immunotherapy by anti-PD-1

Antibodies that block the interaction between PD-1 and PD-1 ligands (anti-PD-1) are in clinical use for the treatment of cancer, yet their efficacy is limited. Pre-approved therapies that enhance the effect of anti-PD-1 in combination are beneficial. Small-molecule inhibitors that attenuate T cell receptor signaling are reported to prevent T cell exhaustion and induce memory T cells with stem cell potential, resulting in a durable effector T cell response in combination with anti-PD-1. In search of such targets, we focused on protein kinase D (PKD), which is suggested to be suppressive in both tumor growth and TCR signaling. We report that CRT0066101, a PKD inhibitor (PKDi), suppressed the growth of mouse tumors at a sub-micromolar concentration in vitro. Despite its inhibitory effects on tumors, a single treatment of tumor-bearing mice with PKDi did not inhibit, but rather accelerated tumor growth, and reversed the therapeutic effect of anti-PD-1. Mice treated with PKDi showed reduced T cell infiltration and defects in the generation of effector T cells, compared to those treated with anti-PD-1, suggesting that PKDi inhibited ongoing antitumor responses. Mechanistically, PKDi inhibited phosphorylation of AKT, a primary checkpoint that is reactivated by anti-PD-1. In conclusion, PKD is fundamentally required for T cell reactivation by anti-PD-1; therefore, inhibition of PKD is not appropriate for combination therapy with anti-PD-1. On the other hand, a single dose of PKDi was shown to strongly suppress experimental autoimmunity in mice, indicating that PKDi could be useful for the treatment of immune-related adverse events that are frequently reported in anti-PD-1 therapy.

Peripheral-dominant liver fibrosis and tumor distribution in a mouse model of congestive hepatopathy

AIM

Congestive hepatopathy often leads to liver fibrosis and hepatocellular carcinoma. Imaging modalities provided clinical evidence that elevation of liver stiffness and tumor occurrence are mainly induced in the periphery of the liver in patients with congestive hepatopathy. However, clinical relevance of liver stiffness and liver fibrosis is unclear because liver congestion itself increases liver stiffness in congestive hepatopathy. It also unclear which factors configure such regional disparity of tumor development in patients with congestive hepatopathy. To answer these questions, we evaluated the macroscopic spatial distribution of liver fibrosis and tumors in the murine model of congestive hepatopathy.

METHODS

Chronic liver congestion was induced by partial ligation of the suprahepatic inferior vena cava. Distribution of liver congestion, fibrosis, and tumors in partial ligation of the suprahepatic inferior vena cava mice were assessed by histological findings, laser microdissection (LMD)-based qPCR and enhanced computed tomography. LMD-based RNA-sequencing was performed to identify causal factors that promote tumor development in congestive hepatopathy.

RESULTS

Liver fibrosis was mainly induced in the periphery of the liver and co-localized with distribution of liver congestion. Liver tumors were also induced in the periphery of the liver where liver congestion and fibrosis occurred. LMD-based RNA-sequencing revealed the upregulation of extracellular matrix/collagen fibril-, wound healing-, angiogenesis-, morphogenesis-, and cell motility-related signaling pathways in periphery of liver compared with liver center.

CONCLUSIONS

Our findings showed the experimental relevance of liver congestion, fibrosis, and tumor development in congestive hepatopathy, and may provide important locational information. Macroscopic regional disparity observed in this murine model should be considered to manage patients with congestive hepatopathy.

Potent and biostable inhibitors of the main protease of SARS-CoV-2

Potent and biostable inhibitors of the main protease (Mpro) of SARS-CoV-2 were designed and synthesized based on an active hit compound 5h (2). Our strategy was based not only on the introduction of fluorine atoms into the inhibitor molecule for an increase of binding affinity for the pocket of Mpro and cell membrane permeability but also on the replacement of the digestible amide bond by a surrogate structure to increase the biostability of the compounds. Compound 3 is highly potent and blocks SARS-CoV-2 infection in vitro without a viral breakthrough. The derivatives, which contain a thioamide surrogate in the P2-P1 amide bond of these compounds (2 and 3), showed remarkably preferable pharmacokinetics in mice compared with the corresponding parent compounds. These data show that compounds 3 and its biostable derivative 4 are potential drugs for treating COVID-19 and that replacement of the digestible amide bond by its thioamide surrogate structure is an effective method.

ETS1 governs pathological tissue-remodeling programs in disease-associated fibroblasts

Fibroblasts, the most abundant structural cells, exert homeostatic functions but also drive disease pathogenesis. Single-cell technologies have illuminated the shared characteristics of pathogenic fibroblasts in multiple diseases including autoimmune arthritis, cancer and inflammatory colitis. However, the molecular mechanisms underlying the disease-associated fibroblast phenotypes remain largely unclear. Here, we identify ETS1 as the key transcription factor governing the pathological tissue-remodeling programs in fibroblasts. In arthritis, ETS1 drives polarization toward tissue-destructive fibroblasts by orchestrating hitherto undescribed regulatory elements of the osteoclast differentiation factor receptor activator of nuclear factor-κB ligand (RANKL) as well as matrix metalloproteinases. Fibroblast-specific ETS1 deletion resulted in ameliorated bone and cartilage damage under arthritic conditions without affecting the inflammation level. Cross-tissue fibroblast single-cell data analyses and genetic loss-of-function experiments lent support to the notion that ETS1 defines the perturbation-specific fibroblasts shared among various disease settings. These findings provide a mechanistic basis for pathogenic fibroblast polarization and have important therapeutic implications.

OP0110 CELL-TYPE-SPECIFIC TRANSCRIPTOME ARCHITECTURE UNDERLYING THE ESTABLISHMENT AND EXACERBATION OF SYSTEMIC LUPUS ERYTHEMATOSUS

Background

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with unknown etiology involving multiple immune cells and has diverse clinical phenotypes. This heterogeneous nature has hampered a better understanding of SLE pathogenesis and the development of effective therapeutic agents. While recent single-cell RNA sequencing studies of SLE identified several important cell subpopulations, they were limited by sparse expression information at single-cell level and small sample sizes.

Objectives

This study aimed to elucidate the dysregulated gene expression pattern linked to multiple clinical statuses of SLE with a fine cellular resolution and higher sensitivity. We also attempted to resolve a complex interaction between risk variants and the transcriptome dysregulation seen in SLE patients.

Methods

We conducted a large-scale bulk transcriptome study of 6,386 RNA-sequencing data including 27 purified immune cell types in peripheral blood from 136 SLE and 89 healthy donors in the Immune Cell Gene Expression Atlas from the University of Tokyo (ImmuNexUT) cohort1. At enrollment, SLE patients had diverse clinical manifestations (disease activity, organ involvement and treatment profiles) and 22 patients were re-evaluated after belimumab treatment.

Results

We first profiled two distinct cell-type-specific transcriptomic signatures: disease-state and disease-activity signatures, reflecting disease establishment and exacerbation, respectively.

After confirming the high replicability of both signatures in independent cohorts, we identified candidates of biological processes unique to each signature: e.g., upregulated E2F transcriptional activity in Th1, CD8+ memory T-lineage and NK cells, and dynamic increase of IL21 and CXCL13 in Th1 cells in an active phase of SLE. Pathway analysis highlighted the importance of immunometabolic process for SLE (e.g., oxidative phosphorylation) in cell-type-specific resolution.

Moreover, we demonstrated cell-type-specific contributions to diverse organ involvement, e.g., Th1 for mucocutaneous, monocyte-lineage cells for musculoskeletal, neutrophil-lineage cells for renal activity, respectively.

We also observed the strong associations of disease-activity signatures with treatment effect: (i) belimumab suppressed activity signatures from B-lineage cells, especially in good responders and (ii) mycophenolate mofetil substantially suppressed activity signatures from plasmablast, Th1, and central memory CD8 cells.

However, through stratified LD score regression using large-scale SLE-GWASs, we revealed that disease-activity signatures were less enriched around SLE risk variants than disease-state signatures. Consistent with this result, the directions of SLE risk alleles’ expression quantitative trait locus (eQTL) effects were significantly concordant with the directions of disease-state signatures, but not with those of activity signatures. These findings suggested that the current genetic case-control studies may not well capture clinically vital biology linked to drug target discovery for SLE. Meanwhile, we also detected some examples of activity signatures that might contribute to the disease risk by modulating risk allele’s eQTL effects.

Figure 1.

Conclusion

We identified comprehensive gene signatures reflecting the establishment and exacerbation of SLE, which provide essential foundations for future genomic, genetic, and clinical studies.

References

[1]Ota, M. et al. Dynamic landscape of immune cell-specific gene regulation in immune-mediated diseases. Cell 2021;184:3006-21.e17.

Acknowledgements

This study was supported by Chugai Pharmaceutical Co., Ltd., Tokyo, Japan; the Ministry of Education, Culture, Sports; and the Japan Agency for Medical Research and Development (AMED) (JP21tm0424221 and JP21zf0127004).

Disclosure of Interests

Masahiro Nakano: None declared, Mineto Ota Grant/research support from: Mineto Ota belongs to the Social Cooperation Program, Department of functional genomics and immunological diseases, supported by Chugai Pharmaceutical., Yusuke Takeshima Grant/research support from: Yusuke Takeshima belonged to the Social Cooperation Program, Department of functional genomics and immunological diseases, supported by Chugai Pharmaceutical., Yukiko Iwasaki: None declared, Hiroaki Hatano: None declared, Yasuo Nagafuchi Grant/research support from: Yasuo Nagafuchi belongs to the Social Cooperation Program, Department of functional genomics and immunological diseases, supported by Chugai Pharmaceutical., Kwangwoo Kim: None declared, So-Young Bang: None declared, Hye Soon Lee: None declared, Hirofumi Shoda: None declared, Xuejun Zhang: None declared, Sang-Cheol Bae: None declared, Chikashi Terao: None declared, Kazuhiko Yamamoto: None declared, Tomohisa Okamura Grant/research support from: Tomohisa Okamura belongs to the Social Cooperation Program, Department of functional genomics and immunological diseases, supported by Chugai Pharmaceutical., Kazuyoshi Ishigaki: None declared, Keishi Fujio Speakers bureau: Keishi Fujio receives speaker fees from Chugai Pharmaceutical., Consultant of: Keishi Fujio receives consulting honoraria from Chugai Pharmaceutical., Grant/research support from: Keishi Fujio receives research support from Chugai Pharmaceutical.

The versatile electric condition in mouse embryos for genome editing using a three-step square-wave pulse electroporator

Technique for Animal Knockout system by Electroporation (TAKE) is a simple and efficient method to generate genetically modified (GM) mice using the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) systems. To reinforce the versatility of electroporation used for gene editing in mice, the electric condition was optimized for vitrified-warmed mouse embryos, and applied to the fresh embryos from widely used inbred strains (C57BL/6NCr, BALB/cCrSlc, FVB/NJcl, and C3H/HeJJcl). The electric pulse settings (poring pulse: voltage, 150 V; pulse width, 1.0 ms; pulse interval, 50 ms; number of pulses, +4; transfer pulse: voltage, 20 V; pulse width, 50 ms; pulse interval, 50 ms; number of pulses, ±5) were optimal for vitrified-warmed mouse embryos, which could efficiently deliver the gRNA/Cas9 complex into the zygotes without zona pellucida thinning process and edit the target locus. These electric condition efficiently generated GM mice in widely used inbred mouse strains. In addition, electroporation using the electrode with a 5 mm gap could introduce more than 100 embryos within 5 min without specific pretreatment and sophisticated technical skills, such as microinjection, and exhibited a high developmental rate of embryos and genome-editing efficiency in the generated offspring, leading to the rapid and efficient generation of genome editing mice. The electric condition used in this study is highly versatile and can contribute to understanding human diseases and gene functions by generating GM mice more easily and efficiently.

Validity of a selective recall method for assessing water intake and its relationship with hydration status

OBJECTIVE

We previously established a descriptive dietary record method that accurately quantifies habitual water intake from food and beverages, to ascertain the relationship between water intake and health. Here, we verified the validity of a selective recall method, which is easy for users to answer and analyze.

PATIENTS AND METHODS

Japanese men and women aged 20-44 years (n = 16) and 45-64 years (n = 16) participated over three working days and one non-working day. The day following each of the surveyed days, participants collected their first morning urine for urinalysis and completed a selective recall and descriptive dietary record questionnaire.

RESULTS

The two methods of determining water intake were positively correlated (r = 0.94, p < 0.0001). Water intake volumes from non-alcoholic beverages (r = 0.94, p < 0.0001), alcoholic beverages (r = 1.00, p < 0.0001), and food (r = 0.72, p < 0.0001), calculated using the two methods, exhibited strong correlation. No correlation was observed between urinalysis parameters and total water intake. A significant, negative correlation was observed between urine osmolarity and total water intake in men (r = -0.55, p = 0.0011) and women (r = -0.51, p = 0.0032) aged 20-44 years.

CONCLUSIONS

Selective recall is a valid method for assessing water intake from food and beverages.

Providing mammography in workplaces improved screening rates: cluster randomized controlled trial

Background

Despite sufficient evidence on the importance of breast cancer screening, the screening rate has remained less than 50% in Japan. To promote behavioral change of individuals, it is important to reduce barriers to taking screening. The purpose of this study was to examine the effect of an environmental approach providing opportunities for mammography (MMG) in workplaces.

Methods

Female employees aged 40 years or older were eligible. Supermarket stores were randomly assigned into two groups, the intervention arm (leaflet and MMG) and the control arm (leaflet). From May to July 2018, participants in the intervention arm were given a leaflet informing the subsidies for breast cancer screening and were provided the opportunity to have MMG in their workplace. Participants in the control group were given the same leaflet, but they had to take the screening outside the workplace as usual. The primary outcome was the breast cancer screening rate in 2018, evaluated using self-administered questionnaires. The odds ratio (OR) and 95% confidence intervals (CIs) for the screening rate in the intervention arm compared with the control arm was estimated using multilevel logistic regression.

Results

We analyzed 1624 participants (mean age was 53 years) from 25 supermarket stores (intervention: 578 patients in 8 stores, control: 1046 patients in 17 stores). The screening rate in the intervention arm was 312 (54%) and was 125 (12%) in the control arm. The OR (and 95% CIs) was 7.81 (5.03-12.12) in the final model adjusted store level effects (i.e., stores and screening rate in 2017 at each store) and individual age and current smoking.

Conclusions

In a worksite-based cluster-randomized controlled trial conducted in a Japanese population, an environmental approach providing MMG opportunities in workplaces significantly increased the self-reported breast cancer screening rate within one year. (UMIN000030465)

Key messages

Providing the opportunity of mammography in Japanese supermarket stores improved the breast cancer screening rate. An environmental approach reducing barriers to screening may be more effective than conventional approaches in improving breast cancer screening rate.

OPG Production Matters Where It Happened

Osteoprotegerin (OPG) is a circulating decoy receptor for RANKL, a multifunctional cytokine essential for the differentiation of tissue-specific cells in bone and immune systems such as osteoclasts, medullary thymic epithelial cells (mTECs), and intestinal microfold cells (M cells). However, it is unknown whether OPG functions only at the production site or circulates to other tissues acting in an endocrine fashion. Here we explore the cellular source of OPG by generating OPG-floxed mice and show that locally produced OPG, rather than circulating OPG, is crucial for bone and immune homeostasis. Deletion of OPG in osteoblastic cells leads to severe osteopenia without affecting serum OPG. Deletion of locally produced OPG increases mTEC and M cell numbers while retaining the normal serum OPG level. This study shows that OPG limits its functions within the tissue where it was produced, illuminating the importance of local regulation of the RANKL system.

Impact of Proteinuria and Low eGFR on Lifetime Risk of Cardiovascular Disease Death: A Pooled Analysis of Data From the Evidence for Cardiovascular Prevention From Observational Cohorts in Japan Study

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): H20–Junkankitou [Seishuu]–Ippan–013; H23–Junkankitou [Seishuu]–Ippan–005; H26-Junkankitou [Seisaku]-Ippan-001; H29–Junkankitou–Ippan–003 and 20FA1002

OnBehalf

EPOCH-JAPAN

Introduction

Absolute risk of Lifetime risk (LTR) is useful estimate for risk communication compared with short term risk or relative risk especially for young people. Proteinuria is leading cause of end-stage kidney disease (ESKD) and independent risk factor for cardiovascular disease (CVD). Although nonproteinuric renal disease is global burden of ESKD, it has been poorly focused. To date, there have been no reports of impact of proteinuria and low eGFR on LTR with the outcome of CVD death in Asian population.

Purpose

We aimed to estimate LTR of CVD death stratified by the status of proteinuria and low eGFR.

Methods

We used modified Kaplan-Meier approach to estimate the remaining lifetime risk of cardiovascular death based on EPOCH-JAPAN(Evidence for Cardiovascular Prevention From Observational Cohorts in Japan) database. LTR was estimated at each index age starting from 40 years for those with proteinuria and without proteinuria stratified by low eGFR, which is defined as eGFR &lt;60 ml/min/1.73 m². Participants were classified into three groups, which were those with proteinuria (Proteinuria (+)), those without proteinuria with low eGFR (Proteinuria (-)/Low eGFR (+)), those without proteinuria without low eGFR (Proteinuria (-)/Low eGFR (-)).

Results

A total of 47,292 participants from 9 cohorts was included in the analysis. Mean follow-up period was 14.6 years with 690,463 person years and total CVD death was 1,075 in men and 1,193 in women. The LTRs at the index age of 40 years were as follows: 17.7% (95% confidence interval: 15.4 – 19.0%) in Proteinuria (-)/Low eGFR (-) group, 26.2% (20.2 – 31.1%) in Proteinuria (-)/low eGFR (+) group, 24.5% (15.1 – 29.3%) in Proteinuria (+) group for men; 15.3%(13.7 – 16.5%), 29.9%(14.7 – 46.8%) , 28.3%(19.4 – 34.7%) for women.

Conclusions

We observed that those without proteinuria with low eGFR have equivalently high LTR with those with proteinuria. These results indicate that even in the absence of proteinuria, low eGFR has high impact on LTR. Lifestyle modification from young age is necessary to prevent from renal dysfunction.

A single amino acid substitution in PRKDC is a determinant of sensitivity to Adriamycin-induced renal injury in mouse

Adriamycin (ADR)-induced nephropathy is frequently utilized in rodent models of podocytopathy. However, the application of this model in mice is limited to a few strains, such as BALB/c mice. The most commonly used mouse strain, C57BL/6 (B6), is resistant to ADR-induced nephropathy, as are all mouse strains with a B6 genetic background. Reportedly, the R2140C variant of the Prkdc gene is the cause of susceptibility to ADR-induced nephropathy in mice. To verify this hypothesis, we produced Prkdc mutant B6 mice, termed B6-Prkdc^R2140C, that possess the R2140C mutation. After administration of ADR, B6-Prkdc^R2140C mice exhibited massive proteinuria and glomerular and renal tubular injuries. In addition, there was no significant difference in the severity between B6-Prkdc^R2140C and BALB/c. These findings demonstrated that B6-Prkdc^R2140C show ADR-induced nephropathy susceptibility at a similar level to BALB/c, and that the PRKDC R2140C variant causes susceptibility to ADR-induced nephropathy. In future studies, ADR-induced nephropathy may become applicable to various kinds of genetically modified mice with a B6 background by mating with B6-Prkdc^R2140C.

New inducible mast cell-deficient mouse model (Mcpt5/Cma1DTR)

Mast cell-deficient mice are helpful for understanding the roles of mast cells in vivo. To date, a dozen mouse models for mast cell deficiency have been reported. However, mice with a specific depletion of all populations of mast cells have not been reported. We generated knock-in mice, termed Mcpt5/Cma1^DTR mice, expressing human diphtheria toxin A (DT) receptor under the endogenous promoter of Mcpt5 (also known as Cma1), which encodes mouse mast cell protease-5. Flow cytometry and histological analysis showed that intraperitoneal injection of DT induced almost complete depletion of mast cells in heterozygote Mcpt5/Cma1^DTR/+ mice. The deletion rates of mast cells in peritoneal cavity, mesentery, abdominal skin, ear skin, and glandular stomach were 99.9%, 100%, 98.7%, 97.7%, and 100%, respectively. Passive cutaneous anaphylaxis reaction also revealed mast cell deficiency in ear skin after DT treatment. Other than mast cells, a small percentage of marginal zone B cells in Mcpt5/Cma1^DTR/+ mice were killed by DT treatment. In conclusion, the Mcpt5/Cma1^DTR/+ mouse model is valuable for achieving conditional depletion of all populations of mast cells without inducing a marked reduction in other cells.

TRIM28 Expression on Dendritic Cells Prevents Excessive T Cell Priming by Silencing Endogenous Retrovirus

Acquired immune reaction is initiated by dendritic cells (DCs), which present Ags to a few naive Ag-specific T cells. Deregulation of gene expression in DCs may alter the outcome of the immune response toward immunodeficiency and/or autoimmune diseases. Expression of TRIM28, a nuclear protein that mediates gene silencing through heterochromatin, decreased in DCs from old mice, suggesting alteration of gene regulation. Mice specifically lacking TRIM28 in DCs show increased DC population in the spleen and enhanced T cell priming toward inflammatory effector T cells, leading to acceleration and exacerbation in experimental autoimmune encephalomyelitis. TRIM28-deficient DCs were found to ectopically transcribe endogenous retrovirus (ERV) elements. Combined genome-wide analysis revealed a strong colocalization among the decreased repressive histone mark H3K9me3-transcribed ERV elements and the derepressed host genes that were related to inflammation in TRIM28-deficient DCs. This suggests that TRIM28 occupancy of ERV elements critically represses expression of proximal inflammatory genes on the genome. We propose that gene silencing through repressive histone modification by TRIM28 plays a role in maintaining the integrity of precise gene regulation in DCs, which prevents aberrant T cell priming to inflammatory effector T cells.

Stepwise cell fate decision pathways during osteoclastogenesis at single-cell resolution

Osteoclasts are the exclusive bone-resorbing cells, playing a central role in bone metabolism, as well as the bone damage that occurs under pathological conditions^1,2. In postnatal life, haematopoietic stem-cell-derived precursors give rise to osteoclasts in response to stimulation with macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand, both of which are produced by osteoclastogenesis-supporting cells such as osteoblasts and osteocytes^1-3. However, the precise mechanisms underlying cell fate specification during osteoclast differentiation remain unclear. Here, we report the transcriptional profiling of 7,228 murine cells undergoing in vitro osteoclastogenesis, describing the stepwise events that take place during the osteoclast fate decision process. Based on our single-cell transcriptomic dataset, we find that osteoclast precursor cells transiently express CD11c, and deletion of receptor activator of nuclear factor-κB specifically in CD11c-expressing cells inhibited osteoclast formation in vivo and in vitro. Furthermore, we identify Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (Cited2) as the molecular switch triggering terminal differentiation of osteoclasts, and deletion of Cited2 in osteoclast precursors in vivo resulted in a failure to commit to osteoclast fate. Together, the results of this study provide a detailed molecular road map of the osteoclast differentiation process, refining and expanding our understanding of the molecular mechanisms underlying osteoclastogenesis.

Determination of phenylalanine enantiomers in the plasma and urine of mammals and ᴅ-amino acid oxidase deficient rodents using two-dimensional high-performance liquid chromatography

A two-dimensional (2D) HPLC system focusing on the determination of phenylalanine (Phe) enantiomers in mammalian physiological fluids has been developed. ᴅ-Phe is indicated to have potential values as a disease biomarker and therapeutic molecule in several neuronal and metabolic disorders, thus the regulation of ᴅ-Phe in mammals is a matter of interest. However, the precise determination of amino acid enantiomers is difficult in complex biological samples, and the development of an analytical method with practically acceptable sensitivity, selectivity and throughput is expected. In the present study, a 2D-HPLC system equipped with a reversed-phase column in the 1st dimension and an enantioselective column in the 2nd dimension has been designed, following the fluorescence derivatization of the target amino acid enantiomers with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). The analytical method was validated using both plasma and urine samples, and successfully applied to human, rat and mouse fluids. Trace levels of ᴅ-Phe were determined in the plasma, and the %ᴅ values were around 0.1% for all species. In the urine, relatively large amounts of ᴅ-Phe were observed, and the %ᴅ values for humans, rats and mice were 3.99, 1.76 and 5.25%, respectively. The relationships between the enzymatic activity of ᴅ-amino acid oxidase (DAO) and the amounts of intrinsic ᴅ-Phe have also been clarified, and high ᴅ-Phe amounts were observed (around 0.3% in the plasma and around 50% in the urine) in the DAO deficient rats and mice.

Hepatic Levels of DHA-Containing Phospholipids Instruct SREBP1-Mediated Synthesis and Systemic Delivery of Polyunsaturated Fatty Acids

Polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and arachidonic acid (ARA), play fundamental roles in mammalian physiology. Although PUFA imbalance causes various disorders, mechanisms of the regulation of their systemic levels are poorly understood. Here, we report that hepatic DHA-containing phospholipids (DHA-PLs) determine the systemic levels of PUFAs through the SREBP1-mediated transcriptional program. We demonstrated that liver-specific deletion of Agpat3 leads to a decrease of DHA-PLs and a compensatory increase of ARA-PLs not only in the liver but also in other tissues including the brain. Together with recent findings that plasma lysophosphatidylcholine (lysoPC) is the major source of brain DHA, our results indicate that hepatic AGPAT3 contributes to brain DHA accumulation by supplying DHA-PLs as precursors of DHA-lysoPC. Furthermore, dietary fish oil-mediated suppression of hepatic PUFA biosynthetic program was blunted in liver-specific Agpat3 deletion. Our findings highlight the central role of hepatic DHA-PLs as the molecular rheostat for systemic homeostasis of PUFAs.

GRL-0920, an Indole Chloropyridinyl Ester, Completely Blocks SARS-CoV-2 Infection

We assessed various newly generated compounds that target the main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and various previously known compounds reportedly active against SARS-CoV-2, employing RNA quantitative PCR (RNA-qPCR), cytopathicity assays, and immunocytochemistry. Here, we show that two indole-chloropyridinyl-ester derivatives, GRL-0820 and GRL-0920, exerted potent activity against SARS-CoV-2 in cell-based assays performed using VeroE6 cells and TMPRSS2-overexpressing VeroE6 cells. While GRL-0820 and the nucleotide analog remdesivir blocked SARS-CoV-2 infection, viral breakthrough occurred. No significant anti-SARS-CoV-2 activity was found for several compounds reportedly active against SARS-CoV-2 such as lopinavir, nelfinavir, nitazoxanide, favipiravir, and hydroxychroloquine. In contrast, GRL-0920 exerted potent activity against SARS-CoV-2 (50% effective concentration [EC50] = 2.8 μM) and dramatically reduced the infectivity, replication, and cytopathic effect of SARS-CoV-2 without significant toxicity as examined with immunocytochemistry. Structural modeling shows that indole and chloropyridinyl of the derivatives interact with two catalytic dyad residues of Mpro, Cys145 and His41, resulting in covalent bonding, which was verified using high-performance liquid chromatography-mass spectrometry (HPLC/MS), suggesting that the indole moiety is critical for the anti-SARS-CoV-2 activity of the derivatives. GRL-0920 might serve as a potential therapeutic for coronavirus disease 2019 (COVID-19) and might be optimized to generate more-potent anti-SARS-CoV-2 compounds.IMPORTANCE Targeting the main protease (Mpro) of SARS-CoV-2, we identified two indole-chloropyridinyl-ester derivatives, GRL-0820 and GRL-0920, active against SARS-CoV-2, employing RNA-qPCR and immunocytochemistry and show that the two compounds exerted potent activity against SARS-CoV-2. While GRL-0820 and remdesivir blocked SARS-CoV-2 infection, viral breakthrough occurred as examined with immunocytochemistry. In contrast, GRL-0920 completely blocked the infectivity and cytopathic effect of SARS-CoV-2 without significant toxicity. Structural modeling showed that indole and chloropyridinyl of the derivatives interacted with two catalytic dyad residues of Mpro, Cys145 and His41, resulting in covalent bonding, which was verified using HPLC/MS. The present data should shed light on the development of therapeutics for COVID-19, and optimization of GRL-0920 based on the present data is essential to develop more-potent anti-SARS-CoV-2 compounds for treating COVID-19.

Chd4 choreographs self-antigen expression for central immune tolerance

Autoreactive T cells are eliminated in the thymus to prevent autoimmunity by promiscuous expression of tissue-restricted self-antigens in medullary thymic epithelial cells. This expression is dependent on the transcription factor Fezf2, as well as the transcriptional regulator Aire, but the entire picture of the transcriptional program has been obscure. Here, we found that the chromatin remodeler Chd4, also called Mi-2β, plays a key role in the self-antigen expression in medullary thymic epithelial cells. To maximize the diversity of self-antigen expression, Fezf2 and Aire utilized completely distinct transcriptional mechanisms, both of which were under the control of Chd4. Chd4 organized the promoter regions of Fezf2-dependent genes, while contributing to the Aire-mediated induction of self-antigens via super-enhancers. Mice deficient in Chd4 specifically in thymic epithelial cells exhibited autoimmune phenotypes, including T cell infiltration. Thus, Chd4 plays a critical role in integrating Fezf2- and Aire-mediated gene induction to establish central immune tolerance.

d-Amino acid oxidase deficiency is caused by a large deletion in the Dao gene in LEA rats

d-Amino acids, enantiomers of l-amino acids, are increasingly recognized as physiologically active molecules as well as potential biomarkers for diseases. d-Amino acid oxidase (DAO) catalyzes the oxidative deamination of d-amino acids and is present in a wide variety of organisms from yeasts to humans. Previous studies indicated that LEA rats lacked DAO activity, and levels of d-Ser and d-Ala were markedly increased in their tissues, suggesting a mutated locus responsible for the lack of Dao activity (ldao) existed in the LEA genome. Sequence analysis identified deletion breakpoints located in intron 4-5 of the Dao gene and intron 1-2 of the Svop gene, resulting in a 54.1-kb deletion which encompassed exons 5-12 of the Dao gene and exons 2-16 of the Svop gene. We developed a novel congenic rat strain, F344-Dao^ldao, harboring the Dao^ldao mutation from LEA rats delivered onto the F344 genetic background. Compared to the parental F344 strain, in F344-Dao^ldao rats d-Ala was markedly increased in both cerebrum and cerebellum, while d-Ser content was increased in cerebellum but not cerebrum. d-Ala, d-Ser, d-Pro and d-Leu levels were also elevated in F344-Dao^ldao plasma. F344-Dao^ldao rats represent a novel model system that will aid in elucidating the physiological functions of d-amino acids in vivo. (203 words).

Genome-wide kinetic properties of transcriptional bursting in mouse embryonic stem cells

Transcriptional bursting is the stochastic activation and inactivation of promoters, contributing to cell-to-cell heterogeneity in gene expression. However, the mechanism underlying the regulation of transcriptional bursting kinetics (burst size and frequency) in mammalian cells remains elusive. In this study, we performed single-cell RNA sequencing to analyze the intrinsic noise and mRNA levels for elucidating the transcriptional bursting kinetics in mouse embryonic stem cells. Informatics analyses and functional assays revealed that transcriptional bursting kinetics was regulated by a combination of promoter- and gene body-binding proteins, including the polycomb repressive complex 2 and transcription elongation factors. Furthermore, large-scale CRISPR-Cas9-based screening identified that the Akt/MAPK signaling pathway regulated bursting kinetics by modulating transcription elongation efficiency. These results uncovered the key molecular mechanisms underlying transcriptional bursting and cell-to-cell gene expression noise in mammalian cells.

THU0225 INTEGRATIVE PLASMA METABOLOME AND TRANSCRIPTOME ANALYSIS REVEALED THE IMPORTANCE OF HISTIDINE HOMEOSTASIS IN SLE PATHOGENESIS WITH POTENTIAL FOR IMPROVED SLE PATIENTS STRATIFICATION

Background:

Recently, immunometabolism has gathered attention of many immunologists. It has been widely recognized that metabolic reprogramming in each immune cell brings different effects on different cells and is important for regulating their functions. Along with the progress of statistical genetics, serum metabolites were shown to be under genetic regulations1). Metabolic changes are now considered not only to be mere phenotypes of cells but also to be key factors for controlling immune cell differentiation, proliferation and function through regulating gene expressions eventually. Although genome-wide association studies have brought deep insights into SLE pathogenesis, the precise pathway from genome to metabolome has been largely unknown, and vice versa.

Objectives:

The aim of this study is to investigate metabolomic regulation in SLE in relation to gene expressions by integrating plasma metabolome data and transcriptome data.

Methods:

We collected plasma samples from patients with SLE (n=57) who met the 1997 American College of Rheumatology criteria for SLE. Gender- and age-matched healthy controls (HCs) (n=56) were recruited. Metabolic profiles focusing on 39 amino acids were analyzed with liquid chromatography (LC)-mass spectrometry. Transcriptome data of SLE patients were obtained from our RNA-sequencing data of each immune cell subset (total 19 subsets). Whole-genome sequencing was also performed.

Results:

Our previous experiment showed that about 160 peaks were detected from comprehensive LC-TOFMS and amino acids were useful for distinguishing SLE patients from HCs. Both partial least squares discriminant analysis (PLS-DA) and random forest, a machine learning algorithm, revealed the importance of histidine (His), one of the essential amino acids, to classify SLE patients from HCs, whose plasma level was lower in SLE patients. In addition, inverse correlation between His level and titer of ds-DNA as well as damage index (SDI) was detected. His level was correlated neither with PSL dosage nor with type I interferon (IFN) signature. Receiver operating characteristic (ROC) analysis showed the best predictability for SLE with the combination of specific amino acids including His. Our transcriptome analysis has revealed the significance of oxidative phosphorylation (OXPHOS) in B cells for SLE pathogenesis. Interestingly, OXPHOS signature was inversely correlated with His level in SLE B cells.

Conclusion:

His may be an important factor for SLE pathogenesis especially in B cells independently from IFN signal. SLC15A4, a transporter of His on lysosome, is one of the SLE GWAS SNPs and has been reported to play an important role in IFN production in B cells through regulation of TLR7/9 activation 2). We also identified that SLE patients with risk allele of SLC15A4 had tendency to show higher plasma His level, indicating His homeostasis could become a novel treatment target for SLE. Moreover, the inverse correlation of His level to SDI as well as OXPHOS signature suggests that His might play a key role for promoting organ damages in SLE.

References:

[1]Nat Genet.2017;49:568. 2)Immunity. 2014;41:375. 3)Semin Arthritis Rheum.2019;48:1142

Disclosure of Interests: :

Yukiko Iwasaki: None declared, Yusuke Takeshima: None declared, Masahiro Nakano: None declared, Mineto Ota: None declared, Yasuo Nagafuchi: None declared, Akari Suzuki: None declared, Yuta Kochi: None declared, Tomohisa Okamura: None declared, Takaho Endo: None declared, Ichiro Miki: None declared, Kazuhiro Sakurada: None declared, Kazuhiko Yamamoto Grant/research support from: Astellas, BMS, MitsubishiTanabe, Pfizer, Ayumi, Takeda, Chugai, Eisai, Taisho Toyama, UCB, and ImmunoFuture, Keishi Fujio Grant/research support from: Astellas, BMS, MitsubishiTanabe, Pfizer, Ayumi, Takeda, Chugai, Eisai, Taisho Toyama, Eli Lilly, Sanofi, and UCB

CANT1 deficiency in a mouse model of Desbuquois dysplasia impairs glycosaminoglycan synthesis and chondrocyte differentiation in growth plate cartilage

Desbuquois dysplasia (DD) type 1 is a rare skeletal dysplasia characterized by a short stature, round face, progressive scoliosis, and joint laxity. The causative gene has been identified as calcium‐activated nucleotidase 1 (CANT1), which encodes a nucleotidase that preferentially hydrolyzes UDP to UMP and phosphate. In this study, we generated Cant1 KO mice using CRISPR/Cas9‐mediated genome editing. All F0 mice possessing frameshift deletions at both Cant1 alleles exhibited a dwarf phenotype. Germline transmission of the edited allele was confirmed in an F0 heterozygous mouse, and KO mice were generated by crossing of the heterozygous breeding pairs. Cant1 KO mice exhibited skeletal defects, including short stature, thoracic kyphosis, and delta phalanx, all of which are observed in DD type 1 patients. The glycosaminoglycan (GAG) content and extracellular matrix space were reduced in the growth plate cartilage of mutants, and proliferating chondrocytes lost their typical flat shape and became round. Chondrocyte differentiation, especially terminal differentiation to hypertrophic chondrocytes, was impaired in Cant1 KO mice. These findings indicate that CANT1 is involved in the synthesis of GAG and regulation of chondrocyte differentiation in the cartilage and contribute to a better understanding of the pathogenesis of DD type 1.

Deletion of the Tensin2 SH2-PTB domain, but not the loss of its PTPase activity, induces podocyte injury in FVB/N mouse strain

Tensin2 (TNS2) is a focal adhesion-localized protein possessing N-terminal tandem protein tyrosine phosphatase (PTPase) and C2 domains, and C-terminal tandem Src homology 2 (SH2) and phosphotyrosine binding (PTB) domains. Genetic deletion of Tns2 in a susceptible murine strain leads to podocyte alterations after birth. To clarify the domain contributions to podocyte maintenance, we generated two Tns2-mutant mice with the genetic background of the susceptible FVB/NJ strain, Tns2^∆C and Tns2^CS mice, carrying a SH2-PTB domain deletion and a PTPase domain inactivation, respectively. The Tns2^∆C mice developed massive albuminuria, severe glomerular injury and podocyte alterations similarly to those in Tns2-deficient mice. In contrast, the Tns2^CS mice showed no obvious phenotypic abnormalities. These results indicate that the TNS2 SH2-PTB domain, but not its PTPase activity, plays a role in podocyte maintenance. Furthermore, in a podocyte cell line, the truncated TNS2 mutant lacking the SH2-PTB domain lost the ability to localize to focal adhesion. Taken together, these data suggest that TNS2 recruitment to focal adhesion is required to maintain postnatal podocytes on a susceptible genetic background.

Age-related and seasonal change in serum osmolarity and water intake in a healthy population

Background and aim

Few studies have clarified the seasonal and age-related change of serum osmolarity and water intake, which is thought to be associated with heat stroke and ischemic stroke. We investigated the association between them in a healthy population.

Methods

We conducted a cross-sectional study using database from Kobe Orthopedic and Biomedical Epidemiologic (KOBE) Study. Among 1138 healthy Japanese participants in the baseline survey, 1010 (women 704 and men 306) participants were eligible for the present study. Daily non-alcohol drink (NAD) intake was estimated according to food frequency questionnaire. Alcohol beverage and water in the meal or soup were excluded from the counting. Serum osmolarity (Osm/L) was calculated by Worthley’s formula: 2 (serum sodium (mEq/L)) + (blood urea nitrogen (mg/dL))/2.8 + (glucose (mg/dL))/18. The seasons the surveys were conducted were categorized into 4 groups, March-May (Spring), June-August (Summer), September-November (Autumn), and December-February (Winter). The association between serum osmolarity and daily NAD intake was analyzed using linear regression models.

Results

The seasonal change was observed in the serum osmolarity and daily NAD intake; serum osmolarity increased in spring and summer and daily NAD intake increased in summer. The serum osmolarity increased by aging in any seasons, while daily water intake didn’t. There was no significant association observed between serum osmolarity and the daily NAD intake, even after adjusting for sex, age, and season.

Conclusions

Serum osmolarity showed seasonal and age-related changes, but the serum osmolarity in subjects who had the daily habit of high NAD intake was not necessarily low.

Key messages

Serum osmolarity increased by aging and in spring and summer. Serum osmolarity was not associated with non-alcohol drink intake.

Serum modified HDL was associated with cardiovascular disease in a Japanese community-based cohort

Background

Previous studies have shown that high density lipoprotein (HDL) is protective against cardiovascular disease (CVD). However, recent studies suggested that function of HDL was more important than HDL cholesterol levels. The present study aimed to clarify the relationship between modified HDL levels and CVD incidence.

Methods

LOX-1 (lectin-like oxidized LDL receptor) is the receptor that mediates modified LDL (low density lipoprotein) activity; however, some lipoproteins with apolipoprotein A1 (Apo A-1) are also bonded to LOX-1. In this study, serum LOX-1 ligand containing Apo A-1 was defined as modified HDL, which were measured by our new development method. We conducted a nested case-control study in a Japanese cohort study, involving 11,002 community dwellers. During 4.0 years follow-up, we observed 127 new CVD onsets. For each CVD case, age and sex matched three controls were randomly selected (N = 381). Serum samples collected at baseline survey stored at − 80 °C were used for the measurement of modified HDL. We estimated multivariable-adjusted odds ratio (OR) and 95% confidence interval (CI) for the association between modified HDL levels and CVD by conditional logistic regression.

Results

Modified HDL levels were associated with increased risk of CVD (OR for one unit increase of log transformed modified HDL, 2.05: 95% CI, 1.16-3.62) after adjustment for body mass index, hypertension, diabetes, LDL cholesterol, HDL cholesterol, lipid lowering agents, chronic kidney disease, smoking and alcohol drinking. The magnitude of OR was almost equivalent to those of hypertension and diabetes, which were 2.33 (95% CI, 1.37-3.98) and 2.61 (95% CI, 1.48-4.59), respectively. On the other hands, other lipids markers showed relatively weak associations with CVD.

Conclusions

Serum modified HDL, i.e., LOX-1 ligand containing Apo A-1, might be a novel predictive marker for CVD in apparently healthy individuals.

Key messages

Recent epidemiologic studies suggested that function of high-density lipoprotein (HDL) was more important than HDL cholesterol level itself to predict cardiovascular disease. Modified HDL measured by a novel cell-free, non-fluorescent method as LOX-1 ligand containing Apo A-1, was a predictive marker for CVD after adjusting for other traditional risk factors.

Presence of intimate family and cancer screening behavior: a cross-sectional study of 4237 workers

Background

Presence of intimate family is considered as one of the related factors of health behaviors. The study aim was to clarify the relationship between the presence of significant others and having a colorectal cancer screening.

Methods

This study used data of baseline survey of intervention study regarding breast cancer screening at worksites. A total of 6827 workers, aged 40 and over of the retail company, were required to fill out a self-administrated questionnaire related to cancer screening. the intimate family was defined as a person’s spouse or partner and children. Logistic regression analyses were performed to estimate odds ratios [ORs] and 95% confidence intervals [CIs] of undergoing an annual screening for colorectal cancer by the presence of spouse or partner adjusting for age. The same analysis was performed regarding the presence of children.

Results

Response rates were 70% in men and 71% in women. After excluding participants with a past history of cancer and lack of information about colorectal cancer screening or the presence of significant others, 4203 remained for the analyses. A total of 1777 participants reported that they had undergone screening for colorectal cancer within a year (42% in men and 42% in women). Screening rates of participants with/without a spouse were 45% and 30% in men, 44% and 38% in women. Screening rates of participants with/without children were 45% and 33% in men, 43% and 38% in women. ORs of undergoing annual colorectal cancer screening by the presence of spouse were 1.8 (1.3-2.5) in men and 1.3 (1.1-1.5) in women. ORs by the presence of children were 1.6 (1.2-2.1) in men and 1.1 (0.9-1.3) in women.

Conclusions

This study indicated that health behavior in cancer screening could be affected by having a spouse in both men and women. The presence of children positively related in men. Male workers with children might be under some pressure to keep their health, from a sense of responsibility of main income earner.

Key messages

Health behavior in cancer screening could be affected by having a spouse. Health behavior in cancer screening could be affected by having a child only in men.

Soluble RANKL is physiologically dispensable but accelerates tumour metastasis to bone

Receptor activator of NF-κB ligand (RANKL) is a multifunctional cytokine known to affect immune and skeletal systems, as well as oncogenesis and metastasis^1-4. RANKL is synthesized as a membrane-bound molecule, and cleaved into its soluble form by proteases^5-7. As the soluble form of RANKL does not contribute greatly to bone remodelling or ovariectomy-induced bone loss⁸, whether soluble RANKL has a role in pathological settings remains unclear. Here we show that soluble RANKL promotes the formation of tumour metastases in bone. Mice that selectively lack soluble RANKL (Tnfsf11^ΔS/ΔS)^5-7,9 have normal bone homoeostasis and develop a normal immune system but display markedly reduced numbers of bone metastases after intracardiac injection of RANK-expressing melanoma and breast cancer cells. Deletion of soluble RANKL does not affect osteoclast numbers in metastatic lesions or tumour metastasis to non-skeletal tissues. Therefore, soluble RANKL is dispensable for physiological regulation of bone and immune systems, but has a distinct and pivotal role in the promotion of bone metastases.

Mice lacking all of the Skint family genes

γδT cells develop in the thymus and play important roles in protection against infection and tumor development, but the mechanisms by which the thymic microenvironment supports γδT cell differentiation remain largely unclear. Skint1, a B7-related protein expressed in thymic epithelial cells, was shown to be essential for the development of mouse Vγ5Vδ1 γδT cells. The Skint family in mouse consists of 11 members, Skint1-11. Here we generated mutant mice lacking the entire genomic region that contains all of the Skint genes. These mice exhibited a marked reduction of Vγ5Vδ1 γδT cells in the thymus and skin, but surprisingly, had normal development of other γδT cell subsets and leukocytes including αβT, B and myeloid cells. This phenotype is essentially identical to that of Skint1-deficient mice. These results indicate that the Skint family exerts an exclusive function in regulating the development of Vγ5Vδ1 γδT cells and is dispensable for development of other leukocytes.

Ras homolog gene family H (RhoH) deficiency induces psoriasis-like chronic dermatitis by promoting TH17 cell polarization

BACKGROUND

Ras homolog gene family H (RhoH) is a membrane-bound adaptor protein involved in proximal T-cell receptor signaling. Therefore RhoH plays critical roles in the differentiation of T cells; however, the function of RhoH in the effecter phase of the T-cell response has not been fully characterized.

OBJECTIVE

We sought to explore the role of RhoH in inflammatory immune responses and investigated the involvement of RhoH in the pathogenesis of psoriasis.

METHODS

We analyzed effector T-cell and systemic inflammation in wild-type and RhoH-null mice. RhoH expression in T cells in human PBMCs was quantified by using RT-PCR.

RESULTS

RhoH deficiency in mice induced TH17 polarization during effector T-cell differentiation, thereby inducing psoriasis-like chronic dermatitis. Ubiquitin protein ligase E3 component N-recognin 5 (Ubr5) and nuclear receptor subfamily 2 group F member 6 (Nr2f6) expression levels decreased in RhoH-deficient T cells, resulting in increased protein levels and DNA binding activity of retinoic acid-related orphan receptor γt. The consequential increase in IL-17 and IL-22 production induced T cells to differentiate into TH17 cells. Furthermore, IL-22 binding protein/Fc chimeric protein reduced psoriatic inflammation in RhoH-deficient mice. Expression of RhoH in T cells was lower in patients with psoriasis with very severe symptoms.

CONCLUSION

Our results indicate that RhoH inhibits TH17 differentiation and thereby plays a role in the pathogenesis of psoriasis. Additionally, IL-22 binding protein has therapeutic potential for the treatment of psoriasis.

Appropriate management of high-flow priapism based on color Doppler ultrasonography findings in pediatric patients: four case reports and a review of the literature

INTRODUCTION

High-flow priapism in children is a very rare condition, and there is no clear consensus on its management. High-flow priapism is associated with increased cavernosal blood flow and broadly divided into two groups based on the presence or absence of arteriocavernous fistula in the corpora cavernosa.

OBJECTIVE

This study aimed to determine the appropriate management of high-flow priapism based on the existence of arteriocavernous fistula using penile color Doppler ultrasonography (CDU) findings in the pediatric population.

STUDY DESIGN

The cases of four boys aged between 6 and 11 years with high-flow priapism treated between 2009 and 2017 are reported. Two boys had prior perineal trauma, one boy had blunt penile glans trauma, and one had no obvious cause for the condition. All boys initially underwent penile CDU and were treated conservatively or via selective arterial embolization depending upon the presence or absence of an arteriocavernous fistula.

RESULTS

Penile CDU revealed an arteriocavernous fistula inside the corpus cavernosum penis in two of four boys and increased blood flow inside the corpus spongiosum in the remaining boys. The former two boys underwent selective arterial embolization and one boy underwent repeated embolization because of remaining arteriocavernous fistula feeding from the contralateral cavernosal artery, whereas the boys with no arteriocavernous fistula on CDU were managed conservatively. All boys were successfully treated within 1 month, and they had normal morning erection and no evidence of recurrent priapism at the follow-up.

DISCUSSION

Unlike low-flow priapism, high-flow priapism is not a medical emergency. Therefore, conservative therapy is an appropriate initial treatment, although selective arterial embolization can be effective for high-flow priapism with arteriocavernous fistula, with a success rate of 97% and no reported complications to date. Penile CDU is an imaging technique that can detect focal areas of turbulent flow with sensitivity close to 100%. This study has several limitations including a small number of cases, limited follow-up duration, and possibility of spontaneous arteriocavernous fistula closure in cases treated by arterial embolization.

CONCLUSION

Penile CDU could be a reliable tool to diagnose high-flow priapism and detect the presence or absence of arteriocavernous fistula. Although conservative therapy remains the first choice, selective arterial embolization may be an early treatment option when CDU reveals an arteriocavernous fistula.

Novel murine model of congenital diabetes: The insulin hyposecretion mouse

AIMS/INTRODUCTION

Diabetic animal models have made an enormous contribution to our understanding of the etiology of diabetes and the development of new medications. The aim of the present study was to develop and characterize a novel, non-obese murine strain with spontaneous diabetes - the insulin hyposecretion (ihs) mouse.

MATERIALS AND METHODS

During the development of the ICGN.B6-Tns2WT strain as the control for the ICGN-Tns2nph congenital nephrotic strain, diabetic mice were discovered and named ihs mice. Intraperitoneal insulin tolerance test, oral glucose tolerance test and an insulin secretion experiment by the pancreas perfusion system were carried out on ihs mice. The pancreatic islets were examined histologically, and the mRNA expression of pancreatic β-cell-specific genes or genes associated with monogenic diabetes was examined by RT-qPCR.

RESULTS

The ihs mice showed several distinctive diabetes-related characteristics: (i) the onset of diabetes was observed only in the male mice; (ii) there were no differences in insulin content between the ihs and control mice; (iii) impaired insulin secretion was elicited by glucose, potassium chloride and sulfonylureas; (iv) there was a significant reduction of relative β-cell volume with no signs of inflammation or fibrosis; (v) they showed a normal glycemic response to exogenous insulin; and (vi) the mice were not obese.

CONCLUSIONS

The ihs mouse provides a novel murine model of congenital diabetes that shows insulin secretion failure. This model allows not only an analysis of the progression of diabetes, but also the identification of unknown genes involved in insulin secretion.