Context-dependent modification of PFKFB3 in hematopoietic stem cells promotes anaerobic glycolysis and ensures stress hematopoiesis

Metabolic pathways are plastic and rapidly change in response to stress or perturbation. Current metabolic profiling techniques require lysis of many cells, complicating the tracking of metabolic changes over time after stress in rare cells such as hematopoietic stem cells (HSCs). Here, we aimed to identify the key metabolic enzymes that define differences in glycolytic metabolism between steady-state and stress conditions in murine HSCs and elucidate their regulatory mechanisms. Through quantitative 13C metabolic flux analysis of glucose metabolism using high-sensitivity glucose tracing and mathematical modeling, we found that HSCs activate the glycolytic rate-limiting enzyme phosphofructokinase (PFK) during proliferation and oxidative phosphorylation (OXPHOS) inhibition. Real-time measurement of ATP levels in single HSCs demonstrated that proliferative stress or OXPHOS inhibition led to accelerated glycolysis via increased activity of PFKFB3, the enzyme regulating an allosteric PFK activator, within seconds to meet ATP requirements. Furthermore, varying stresses differentially activated PFKFB3 via PRMT1-dependent methylation during proliferative stress and via AMPK-dependent phosphorylation during OXPHOS inhibition. Overexpression of Pfkfb3 induced HSC proliferation and promoted differentiated cell production, whereas inhibition or loss of Pfkfb3 suppressed them. This study reveals the flexible and multilayered regulation of HSC glycolytic metabolism to sustain hematopoiesis under stress and provides techniques to better understand the physiological metabolism of rare hematopoietic cells.

Rev1 overexpression accelerates N-methyl-N-nitrosourea (MNU)-induced thymic lymphoma by increasing mutagenesis

Rev1 has two important functions in the translesion synthesis pathway, including dCMP transferase activity, and acts as a scaffolding protein for other polymerases involved in translesion synthesis. However, the role of Rev1 in mutagenesis and tumorigenesis in vivo remains unclear. We previously generated Rev1-overexpressing (Rev1-Tg) mice and reported that they exhibited a significantly increased incidence of intestinal adenoma and thymic lymphoma (TL) after N-methyl-N-nitrosourea (MNU) treatment. In this study, we investigated mutagenesis of MNU-induced TL tumorigenesis in wild-type (WT) and Rev1-Tg mice using diverse approaches, including whole-exome sequencing (WES). In Rev1-Tg TLs, the mutation frequency was higher than that in WT TL in most cases. However, no difference in the number of nonsynonymous mutations in the Catalogue of Somatic Mutations in Cancer (COSMIC) genes was observed, and mutations involved in Notch1 and MAPK signaling were similarly detected in both TLs. Mutational signature analysis of WT and Rev1-Tg TLs revealed cosine similarity with COSMIC mutational SBS5 (aging-related) and SBS11 (alkylation-related). Interestingly, the total number of mutations, but not the genotypes of WT and Rev1-Tg, was positively correlated with the relative contribution of SBS5 in individual TLs, suggesting that genetic instability could be accelerated in Rev1-Tg TLs. Finally, we demonstrated that preleukemic cells could be detected earlier in Rev1-Tg mice than in WT mice, following MNU treatment. In conclusion, Rev1 overexpression accelerates mutagenesis and increases the incidence of MNU-induced TL by shortening the latency period, which may be associated with more frequent DNA damage-induced genetic instability.

Elevated stress response marks deeply quiescent reserve cells of gastric chief cells

Gastrointestinal tract organs harbor reserve cells, which are endowed with cellular plasticity and regenerate functional units in response to tissue damage. However, whether the reserve cells in gastrointestinal tract exist as long-term quiescent cells remain incompletely understood. In the present study, we systematically examine H2b-GFP label-retaining cells and identify a long-term slow-cycling population in the gastric corpus but not in other gastrointestinal organs. The label-retaining cells, which reside near the basal layers of the corpus, comprise a subpopulation of chief cells. The identified quiescent cells exhibit induction of Atf4 and its target genes including Atf3, a marker of paligenosis, and activation of the unfolded protein response, but do not show elevated expression of Troy, Lgr5, or Mist. External damage to the gastric mucosa induced by indomethacin treatment triggers proliferation of the quiescent Atf4+ population, indicating that the gastric corpus harbors a specific cell population that is primed to facilitate stomach regeneration.

Factors associated with COVID-19 booster vaccine hesitancy: a nationwide, cross-sectional survey in Japan

OBJECTIVES

COVID-19 vaccine hesitancy/fatigue is increasing as the pandemic enters the endemic phase. The present study aimed to explore current perceptions about COVID-19 booster vaccination among the Japanese public.

STUDY DESIGN

This was a cross-sectional study.

METHODS

This cross-sectional study used data from the Japan COVID-19 and Society Internet Survey conducted in September 2021 and September 2022. The public's perceptions of COVID-19 vaccination and factors associated with COVID-19 booster vaccine hesitancy were analyzed.

RESULTS

In total, 56,735 respondents were included. In the Japan COVID-19 and Society Internet Survey 2021, 75.1% of the participants (21,126/28,118) had completed the primary vaccination series. In the 2022 survey, 74.1% of the respondents (21,216/28,617) completed the primary series of vaccination with booster doses. The proportion of fear toward COVID-19 and obtaining information about COVID-19 has decreased from 2021 to 2022. Factors independently associated with booster vaccine hesitancy were young age (range: 18-29 years; adjusted odds ratio [aOR]: 6.56), history of COVID-19 (aOR: 1.82), distrust of the Japanese government's COVID-19 prevention measures (aOR: 1.55), lack of confidence in COVID-19 vaccine efficacy (aOR: 1.30), lack of confidence in COVID-19 vaccine safety (aOR: 1.62), low reliance on the COVID-19 vaccine (aOR: 1.92), and belief in COVID-19 conspiracy theories (aOR: 1.77).

CONCLUSIONS

Providing clear and trustworthy information is critically important, especially targeted and tailored messages for the young generation, to promoting COVID-19 booster vaccination. Policymakers should therefore develop consistent and transparent communication strategies and the ability to respond promptly and flexibly to mitigate the negative impact of COVID-19 on the public while preparing for the next pandemic.

UTX inactivation in germinal center B cells promotes the development of multiple myeloma with extramedullary disease

UTX/KDM6A, a histone H3K27 demethylase and a key component of the COMPASS complex, is frequently lost or mutated in cancer; however, its tumor suppressor function remains largely uncharacterized in multiple myeloma (MM). Here, we show that the conditional deletion of the X-linked Utx in germinal center (GC) derived cells collaborates with the activating BrafV600E mutation and promotes induction of lethal GC/post-GC B cell malignancies with MM-like plasma cell neoplasms being the most frequent. Mice that developed MM-like neoplasms showed expansion of clonal plasma cells in the bone marrow and extramedullary organs, serum M proteins, and anemia. Add-back of either wild-type UTX or a series of mutants revealed that cIDR domain, that forms phase-separated liquid condensates, is largely responsible for the catalytic activity-independent tumor suppressor function of UTX in MM cells. Utx loss in concert with BrafV600E only slightly induced MM-like profiles of transcriptome, chromatin accessibility, and H3K27 acetylation, however, it allowed plasma cells to gradually undergo full transformation through activation of transcriptional networks specific to MM that induce high levels of Myc expression. Our results reveal a tumor suppressor function of UTX in MM and implicate its insufficiency in the transcriptional reprogramming of plasma cells in the pathogenesis of MM.

MBTD1 preserves adult hematopoietic stem cell pool size and function

Mbtd1 (mbt domain containing 1) encodes a nuclear protein containing a zinc finger domain and four malignant brain tumor (MBT) repeats. We previously generated Mbtd1-deficient mice and found that MBTD1 is highly expressed in fetal hematopoietic stem cells (HSCs) and sustains the number and function of fetal HSCs. However, since Mbtd1-deficient mice die soon after birth possibly due to skeletal abnormalities, its role in adult hematopoiesis remains unclear. To address this issue, we generated Mbtd1 conditional knockout mice and analyzed adult hematopoietic tissues deficient in Mbtd1. We observed that the numbers of HSCs and progenitors increased and Mbtd1-deficient HSCs exhibited hyperactive cell cycle, resulting in a defective response to exogenous stresses. Mechanistically, we found that MBTD1 directly binds to the promoter region of FoxO3a, encoding a forkhead protein essential for HSC quiescence, and interacts with components of TIP60 chromatin remodeling complex and other proteins involved in HSC and other stem cell functions. Restoration of FOXO3a activity in Mbtd1-deficient HSCs in vivo rescued cell cycle and pool size abnormalities. These findings indicate that MBTD1 is a critical regulator for HSC pool size and function, mainly through the maintenance of cell cycle quiescence by FOXO3a.

The pathogenetic significance of exhausted T cells in a mouse model of mature B cell neoplasms

Dysfunctional anti-tumor immunity has been implicated in the pathogenesis of mature B cell neoplasms, such as multiple myeloma and B cell lymphoma; however, the impact of exhausted T cells on disease development remains unclear. Therefore, the present study investigated the features and pathogenetic significance of exhausted T cells using a mouse model of de novo mature B cell neoplasms, which is likely to show immune escape similar to human patients. The results revealed a significant increase in PD-1+ Tim-3- and PD-1+ Tim-3+ T cells in sick mice. Furthermore, PD-1+ Tim-3+ T cells exhibited direct cytotoxicity with a short lifespan, showing transcriptional similarities to terminally exhausted T cells. On the other hand, PD-1+ Tim-3- T cells not only exhibited immunological responsiveness but also retained stem-like transcriptional features, suggesting that they play a role in the long-term maintenance of anti-tumor immunity. In PD-1+ Tim-3- and PD-1+ Tim-3+ T cells, the transcription factors Tox and Nr4a2, which reportedly contribute to the progression of T cell exhaustion, were up-regulated in vivo. These transcription factors were down-regulated by IMiDs in our in vitro T cell exhaustion analyses. The prevention of excessive T cell exhaustion may maintain effective anti-tumor immunity to cure mature B cell neoplasms.

Targeting Poly(ADP)ribose polymerase in BCR/ABL1-positive cells

BCR/ABL1 causes dysregulated cell proliferation and is responsible for chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph1-ALL). In addition to the deregulatory effects of its kinase activity on cell proliferation, BCR/ABL1 induces genomic instability by downregulating BRCA1. PARP inhibitors (PARPi) effectively induce cell death in BRCA-defective cells. Therefore, PARPi are expected to inhibit growth of CML and Ph1-ALL cells showing downregulated expression of BRCA1. Here, we show that PARPi effectively induced cell death in BCR/ABL1 positive cells and suppressed colony forming activity. Prevention of BCR/ABL1-mediated leukemogenesis by PARP inhibition was tested in two in vivo models: wild-type mice that had undergone hematopoietic cell transplantation with BCR/ABL1-transduced cells, and a genetic model constructed by crossing Parp1 knockout mice with BCR/ABL1 transgenic mice. The results showed that a PARPi, olaparib, attenuates BCR/ABL1-mediated leukemogenesis. One possible mechanism underlying PARPi-dependent inhibition of leukemogenesis is increased interferon signaling via activation of the cGAS/STING pathway. This is compatible with the use of interferon as a first-line therapy for CML. Because tyrosine kinase inhibitor (TKI) monotherapy does not completely eradicate leukemic cells in all patients, combined use of PARPi and a TKI is an attractive option that may eradicate CML stem cells.

p130Cas is required for androgen-dependent postnatal development regulation of submandibular glands

Salivary glands develop through epithelial-mesenchymal interactions and are formed through repeated branching. The Crk-associated substrate protein (p130Cas) serves as an adapter that forms a complex with various proteins via integrin and growth factor signaling, with important regulatory roles in several essential cellular processes. We found that p130Cas is expressed in ductal epithelial cells of the submandibular gland (SMG). We generated epithelial tissue-specific p130Cas-deficient (p130Cas^Δepi-) mice and aimed to investigate the physiological role of p130Cas in the postnatal development of salivary glands. Histological analysis showed immature development of granular convoluted tubules (GCT) of the SMG in male p130Cas^Δepi- mice. Immunofluorescence staining showed that nuclear-localized androgen receptors (AR) were specifically decreased in GCT cells in p130Cas^Δepi- mice. Furthermore, epidermal growth factor-positive secretory granules contained in GCT cells were significantly reduced in p130Cas^Δepi- mice with downregulated AR signaling. GCTs lacking p130Cas showed reduced numbers and size of secretory granules, disrupted subcellular localization of the cis-Golgi matrix protein GM130, and sparse endoplasmic reticulum membranes in GCT cells. These results suggest that p130Cas plays a crucial role in androgen-dependent GCT development accompanied with ER-Golgi network formation in SMG by regulating the AR signaling.

Differentiated embryonic chondrocyte expressed gene-1 is a central signaling component in the development of collagen-induced rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases and affects almost 1% of the population. Differentiated embryo-chondrocyte expressed gene-1 (DEC1) has been associated with both osteogenesis and osteoclastogenesis. RA condition is marked by inflammatory hyperplasia, and DEC1 is known to support inflammatory reactions and implicated in antiapoptosis and cell invasion. Here, our goal was to test the hypothesis that DEC1 enhances RA development induced by collagen-induced arthritis (CIA), a well-recognized protocol for developing RA animal models. DEC1^+/+ and DEC1^-/- mice were subjected to CIA protocol, and the development of RA condition was monitored. We found that CIA robustly induced RA phenotypes (e.g., synovial hyperplasia) and greatly increased the expression of proinflammatory cytokines such as TNF-α. However, these changes were detected in DEC1^+/+ but not DEC1^-/- mice. Interestingly, these very cytokines strongly induced DEC1, and such a dual role of DEC1, as an inducer for and being induced by proinflammatory cytokines, constitutes a DEC1-amplifying circuit for inflammation. Knockdown of DEC1 in human MH7A cells strongly decreased cell migration and invasion as well as the expression of genes related to RA phenotypes. The combination of DEC1-directed migration and invasion in vitro with synovial hyperplasia in vivo mechanistically establishes cellular bases on how DEC1 is involved in the development of RA phenotypes. In addition to inflammatory signaling, DEC1 functionally interacted with PI3KCA(p110α)/Akt/GSK3β, Wnt/β-catenin, and NFATc1. Such engagement in multiple signaling pathways suggests that DEC1 plays coordinated and integral roles in developing RA, one of the most common autoimmune diseases.

UTX deficiency in neural stem/progenitor cells results in impaired neural development, fetal ventriculomegaly, and postnatal death

Recent studies have demonstrated that epigenetic modifications are deeply involved in neurogenesis; however, the precise mechanisms remain largely unknown. To determine the role of UTX (also known as KDM6A), a demethylase of histone H3K27, in neural development, we generated Utx-deficient mice in neural stem/progenitor cells (NSPCs). Since Utx is an X chromosome-specific gene, the genotypes are sex-dependent; female mice lose both Utx alleles (Utx^Δ/Δ ), and male mice lose one Utx allele yet retain one Uty allele, the counterpart of Utx on the Y chromosome (Utx^Δ/Uty ). We found that Utx^Δ/Δ mice exhibited fetal ventriculomegaly and died soon after birth. Immunofluorescence staining and EdU labeling revealed a significant increase in NSPCs and a significant decrease in intermediate-progenitor and differentiated neural cells. Molecular analyses revealed the downregulation of pathways related to DNA replication and increased H3K27me3 levels around the transcription start sites in Utx^Δ/Δ NSPCs. These results indicate that UTX globally regulates the expression of genes required for proper neural development in NSPCs, and UTX deficiency leads to impaired cell cycle exit, reduced differentiation, and neonatal death. Interestingly, although Utx^Δ/Uty mice survived the postnatal period, most died of hydrocephalus, a clinical feature of Kabuki syndrome, a congenital anomaly involving UTX mutations. Our findings provide novel insights into the role of histone modifiers in neural development and suggest that Utx^Δ/Uty mice are a potential disease model for Kabuki syndrome.

In utero transplantation of myoblasts and adipose-derived mesenchymal stem cells to murine models of Duchenne muscular dystrophy does not lead to engraftment and frequently results in fetal death

Introduction

Duchenne muscular dystrophy (DMD) is a progressive disease that leads to damage of muscle and myocardium due to genetic abnormalities in the dystrophin gene. In utero cell transplantation that might facilitate allogenic transplantation is worth considering to treat this disease.

Methods

We performed allogeneic in utero transplantation of GFP-positive myoblasts and adipose-derived mesenchymal stem cells into murine DMD model animals. The transplantation route in this study was fetal intraperitoneal transplantation and transplacental transplantation. Transplanted animals were examined at 4-weeks old by immunofluorescence staining and RT-qPCR.

Results

No GFP-positive cells were found by immunofluorescence staining of skeletal muscle and no GFP mRNA was detected by RT-qPCR in any animal, transplantation method and cell type. Compared with previous reports, myoblast transplantation exhibited an equivalent mortality rate, but adipose-derived stem cell (ASC) transplantation produced a higher mortality rate.

Conclusions

In utero transplantation of myoblasts or ASCs to murine models of DMD does not lead to engraftment and, in ASC transplantation primarily, frequently results in fetal death.

Effects of interleukin-6 inhibition with ziltivekimab in patients at high risk of atherosclerotic events in Japan: results from the phase 2 RESCUE-2 trial

Introduction

In the US phase 2 RESCUE trial, ziltivekimab, a fully human monoclonal antibody against the ligand of the pro-inflammatory cytokine interleukin-6, was shown to reduce biomarkers of inflammation in patients with chronic kidney disease (CKD) and elevated levels of high-sensitivity C-reactive protein (hsCRP), a marker of inflammation and cardiac risk.1 Here, we present outcomes from the phase 2 RESCUE-2 trial of ziltivekimab in a patient population from Japan.

Purpose

To evaluate the efficacy and safety of ziltivekimab 15 mg and 30 mg compared with placebo in Japanese patients with non-dialysis-dependent CKD (NDD-CKD).

Methods

We conducted a randomized, double-blind, placebo-controlled trial in 36 patients aged ≥20 years with stage 3–5 NDD-CKD and hsCRP ≥2 mg/L. Patients were randomly assigned to receive subcutaneous ziltivekimab 15 mg (n=11) or 30 mg (n=12), or placebo (n=13) at weeks 0, 4 and 8. The primary endpoint was percentage change in hsCRP levels from baseline to end of treatment (EOT) (average of week 10 and week 12 values); secondary endpoints included percentage change from baseline to EOT in levels of fibrinogen, serum amyloid A (SAA), N-terminal pro B-type natriuretic peptide (NT-proBNP) and lipids. Analysis of endpoints was performed using Wilcoxon two-sample test; differences between treatment groups were calculated using the Hodges–Lehmann estimator.

Results

Baseline characteristics are shown in the Table. At EOT, median hsCRP levels were reduced by 96% and 93% in the ziltivekimab 15 mg and 30 mg groups, respectively, compared with 27% for placebo (both p<0.001 vs placebo). At both doses, ziltivekimab provided rapid and sustained suppression of hsCRP over the 12-week treatment period (Figure). Statistically significant reductions in levels of the inflammatory markers SAA (15 mg: 71%; 30 mg: 58%; placebo: 30%; both p<0.01 vs placebo) and fibrinogen (38%; 34%; 2%; both p<0.0001 vs placebo) were also observed. Ziltivekimab was well tolerated, did not result in persistent neutropenia or thrombocytopenia, and had minimal effect on liver enzyme levels. There was a non-significant increase in low-density lipoprotein levels and a neutral effect on high-density lipoprotein levels. There was a limited, but statistically significant (p<0.05 vs placebo) increase in triglycerides, whereby levels increased in some patients and decreased in others.

Conclusion

Ziltivekimab effectively reduced inflammatory biomarkers associated with atherosclerosis in patients from Japan with CKD and residual inflammatory risk as measured by hsCRP. A significant reduction of more than 90% in hsCRP levels for both doses of ziltivekimab was demonstrated, with a safety profile similar to placebo. Overall, the results of the RESCUE-2 trial in Japan are consistent with the efficacy and safety results of the US-based RESCUE trial.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was funded by Novo Nordisk A/S. Medical writing support was provided by Johanna Scheinost PhD, PharmaGenesis Oxford Central, Oxford, UK, with funding from Novo Nordisk A/S.

Aberrant EVI1 splicing contributes to EVI1-rearranged leukemia

Detailed genomic and epigenomic analyses of MECOM (the MDS1 and EVI1 complex locus) have revealed that inversion or translocation of chromosome 3 drives inv(3)/t(3;3) myeloid leukemias via structural rearrangement of an enhancer that upregulates transcription of EVI1. Here, we identify a novel, previously unannotated oncogenic RNA-splicing derived isoform of EVI1 that is frequently present in inv(3)/t(3;3) acute myeloid leukemia (AML) and directly contributes to leukemic transformation. This EVI1 isoform is generated by oncogenic mutations in the core RNA splicing factor SF3B1, which is mutated in >30% of inv(3)/t(3;3) myeloid neoplasm patients and thereby represents the single most commonly cooccurring genomic alteration in inv(3)/t(3;3) patients. SF3B1 mutations are statistically uniquely enriched in inv(3)/t(3;3) myeloid neoplasm patients and patient-derived cell lines compared with other forms of AML and promote mis-splicing of EVI1 generating an in-frame insertion of 6 amino acids at the 3' end of the second zinc finger domain of EVI1. Expression of this EVI1 splice variant enhanced the self-renewal of hematopoietic stem cells, and introduction of mutant SF3B1 in mice bearing the humanized inv(3)(q21q26) allele resulted in generation of this novel EVI1 isoform in mice and hastened leukemogenesis in vivo. The mutant SF3B1 spliceosome depends upon an exonic splicing enhancer within EVI1 exon 13 to promote usage of a cryptic branch point and aberrant 3' splice site within intron 12 resulting in the generation of this isoform. These data provide a mechanistic basis for the frequent cooccurrence of SF3B1 mutations as well as new insights into the pathogenesis of myeloid leukemias harboring inv(3)/t(3;3).

A novel role of helix-loop-helix transcriptional factor Bhlhe40 in osteoclast activation

The basic helix-loop-helix transcriptional factor, Bhlhe40 has been shown as a crucial regulator of immune response, tumorigenesis, and circadian rhythms. We identified Bhlhe40 as a possible regulator of osteoclast differentiation and function by shRNA library screening and found that Bhlhe40 was required for osteoclast activation. Bhlhe40 expression was induced in bone marrow macrophages (BMMs) by RANKL, whereas the expression of its homolog Bhlhe41 was decreased in osteoclastogenesis. μCT analysis of tibias revealed that Bhlhe40 knockout (KO) mice exhibited increased bone volume phenotype. Bone morphometric analysis showed that osteoclast number and bone resorption were decreased in Bhlhe40 KO mice, whereas significant differences in the osteoblast parameters were not seen between wild-type (WT) and Bhlhe40 KO mice. In vitro culture of BMMs showed that Bhlhe40 deficiency did not cause difference in osteoclast formation. In contrast, bone resorption activity of Bhlhe40 KO osteoclasts was markedly reduced in comparison with that of WT osteoclasts. Analysis of potential target genes of Bhlhe40 using data-mining platform ChIP-Atlas (http://chip-atlas.org) revealed that predicted target genes of Bhlhe40 were related to proton transport and intracellular vesicle acidification. We then analyzed the expression of proton pump, the vacuolar (V)-ATPases which are responsible for bone resorption. The expression of V-ATPases V1c1 and V0a3 was suppressed in Bhlhe40 KO osteoclasts. In addition, Lysosensor yellow/blue DND 160 staining demonstrated that vesicular acidification was attenuated in vesicles of Bhlhe40 KO osteoclasts. Furthermore, analysis with pH-sensitive fluorescent probe showed that proton secretion was markedly suppressed in Bhlhe40 KO osteoclasts compared to that in WT osteoclasts. Our findings suggest that Bhlhe40 plays a novel important role in the regulation of acid production in osteoclastic bone resorption.

Deletion of epithelial cell-specific p130Cas impairs the maturation stage of amelogenesis

Amelogenesis consists of secretory, transition, maturation, and post-maturation stages, and the morphological changes of ameloblasts at each stage are closely related to their function. p130 Crk-associated substrate (Cas) is a scaffold protein that modulates essential cellular processes, including cell adhesion, cytoskeletal changes, and polarization. The expression of p130Cas was observed from the secretory stage to the maturation stage in ameloblasts. Epithelial cell-specific p130Cas-deficient (p130Cas^Δepi-) mice exhibited enamel hypomineralization with chalk-like white mandibular incisors in young mice and attrition in aged mouse molars. A micro-computed tomography analysis and Vickers micro-hardness testing showed thinner enamel, lower enamel mineral density and hardness in p130Cas^Δepi- mice in comparison to p130Cas^flox/flox mice. Scanning electron microscopy, and an energy dispersive X-ray spectroscopy analysis indicated the disturbance of the enamel rod structure and lower Ca and P contents in p130Cas^Δepi- mice, respectively. The disorganized arrangement of ameloblasts, especially in the maturation stage, was observed in p130Cas^Δepi- mice. Furthermore, expression levels of enamel matrix proteins, such as amelogenin and ameloblastin in the secretory stage, and functional markers, such as alkaline phosphatase and iron accumulation, and Na⁺/Ca²⁺+K⁺-exchanger in the maturation stage were reduced in p130Cas^Δepi- mice. These findings suggest that p130Cas plays important roles in amelogenesis (197 words).

The Loss of H3K27 Histone Demethylase Utx in T Cells Aggravates Allergic Contact Dermatitis

The pathogenesis of allergic contact dermatitis (ACD) requires the activation of Ag-specific T cells, including effector and regulatory T cells. The differentiation and function of these T cells is epigenetically regulated through DNA methylation and histone modifications. However, the roles of altered histone H3K27 methylation in T cells in the development of ACD remain unknown. Two types of histone H3K27 demethylases, Utx and Jmjd3, have been reported in mammals. To determine the role of the histone H3K27 demethylase expression of T cells in the development of ACD, we generated T cell-specific, Utx-deficient (Utx KO) mice or Jmjd3-deficient (Jmjd3 KO) mice. Unlike control mice, Utx KO mice had severer symptoms of ACD, whereas Jmjd3 KO mice showed symptoms identical to those in control mice. In Utx KO mice with ACD, the massive infiltration of myeloid cells, including neutrophils and dendritic cells, has been observed. In addition, the expression of proinflammatory cytokines in CD4⁺ T cells of the draining lymph nodes (LNs) and in CD8⁺ T cells of the skin was increased in Utx KO mice, whereas the ratio of Foxp3⁺ regulatory CD4⁺ T cells to Foxp3^- conventional CD4⁺ T cells was decreased in both the draining LNs and the skin of Utx KO mice with ACD. Furthermore, Foxp3⁺ regulatory CD4⁺ T cells of Utx KO mice with ACD expressed a decreased level of CCR4 (a skin-tropic chemokine receptor) in comparison with control. Thus, in CD4⁺ T cells, Utx could potentially be involved in the regulation of the pathogenesis of ACD.

The unique function of p130Cas in regulating the bone metabolism

p130 Crk-associated substrate (Cas) functions as an adapter protein and plays important roles in certain cell functions, such as cell proliferation, spreading, migration, and invasion. Furthermore, it has recently been reported to have a new function as a mechanosensor. Since bone is a tissue that is constantly under gravity, it is exposed to mechanical stress. Mechanical unloading, such as in a microgravity environment in space or during bed rest, leads to a decrease in bone mass because of the suppression of bone formation and the stimulation of bone resorption. Osteoclasts are multinucleated bone-resorbing giant cells that recognize bone and then form a ruffled border in the resorption lacuna. p130Cas is a molecule located downstream of c-Src that is important for the formation of a ruffled border in osteoclasts. Indeed, osteoclast-specific p130Cas-deficient mice exhibit osteopetrosis due to osteoclast dysfunction, similar to c-Src-deficient mice. Osteoblasts subjected to mechanical stress induce both the phosphorylation of p130Cas and osteoblast differentiation. In osteocytes, mechanical stress regulates bone mass by shuttling p130Cas between the cytoplasm and nucleus. Oral squamous cell carcinoma (OSCC) cells express p130Cas more strongly than epithelial cells in normal tissues. The knockdown of p130Cas in OSCC cells suppressed the cell growth, the expression of receptor activator of NF-κB ligand, which induces osteoclast formation, and bone invasion by OSCC. Taken together, these findings suggest that p130Cas might be a novel therapeutic target molecule in bone diseases, such as osteoporosis, rheumatoid arthritis, bone loss due to bed rest, and bone invasion and metastasis of cancer.

Pathological Role of Pin1 in the Development of DSS-Induced Colitis

Inflammatory bowel diseases (IBDs) are serious disorders of which the etiologies are not, as yet, fully understood. In this study, Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) protein was shown to be dramatically upregulated in the colons of dextran sodium sulfate (DSS)-induced ulcerative colitis model mice. Interestingly, Pin1 knockout (KO) mice exhibited significant attenuation of DSS-induced colitis compared to wild-type (WT) mice, based on various parameters, including body weight, colon length, microscopic observation of the intestinal mucosa, inflammatory cytokine expression, and cleaved caspase-3. In addition, a role of Pin1 in inflammation was suggested because the percentage of M1-type macrophages in the colon was decreased in the Pin1 KO mice while that of M2-type macrophages was increased. Moreover, Pin1 KO mice showed downregulation of both Il17 and Il23a expression in the colon, both of which have been implicated in the development of colitis. Finally, oral administration of Pin1 inhibitor partially but significantly prevented DSS-induced colitis in mice, raising the possibility of Pin1 inhibitors serving as therapeutic agents for IBD.

Progress of genome editing technology and developmental biology useful for radiation research

Following the development of genome editing technology, it has become more feasible to create genetically modified animals such as knockout (KO), knock-in, and point-mutated animals. The genome-edited animals are useful to investigate the roles of various functional genes in many fields of biological science including radiation research. Nevertheless, some researchers may experience difficulty in generating genome-edited animals, probably due to the requirement for equipment and techniques for embryo manipulation and handling. Furthermore, after obtaining F0 generation, genome-edited animals generally need to be expanded and maintained for analyzing the target gene function. To investigate genes essential for normal birth and growth, the generation of conditional KO (cKO) animals in which a tissue- or stage-specific gene mutation can be introduced is often required. Here, we describe the basic principle and application of genome editing technology including zinc-finger nuclease, transcription-activator-like effector nuclease, and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated protein (Cas) systems. Recently advanced developmental biology methods have enabled application of the technology, especially CRISPR/Cas, to zygotes, leading to the prompt production of genome-edited animals. For pre-implantation embryos, genome editing via oviductal nucleic acid delivery has been developed as an embryo manipulation- or handling-free method. Examining the gene function at F0 generation is becoming possible by employing triple-target CRISPR technology. This technology, in combination with a blastocyst complementation method enables investigation of even birth- and growth-responsible genes without establishing cKO strains. We hope that this review is helpful for understanding and expanding genome editing-related technology and for progressing radiation research.

DEC1 deficiency results in accelerated osteopenia through enhanced DKK1 activity and attenuated PI3KCA/Akt/GSK3β signaling

BACKGROUND

Human differentiated embryonic chondrocyte expressed gene 1 (DEC1) has been implicated in enhancing osteogenesis, a desirable outcome to counteract against deregulated bone formation such as retarded bone development, osteopenia and osteoporosis.

METHODS AND RESULTS

DEC1 knockout (KO) and the age-matched wild-type (WT) mice were tested for the impact of DEC1 deficiency on bone development and osteopenia as a function of age. DEC1 deficiency exhibited retarded bone development at the age of 4 weeks and osteopenic phenotype in both 4- and 24-week old mice. However, the osteopenia was more severe in the 24-week age groups. Mechanistically, DEC1 deficiency downregulated the expression of bone-enhancing genes such as Runx2 and β-catenin accompanied by upregulating DKK1, an inhibitor of the Wnt/β-catenin signaling pathway. Consistently, DEC1 deficiency favored the attenuation of the integrated PI3KCA/Akt/GSK3β signaling, a pathway targeting β-catenin for degradation. Likewise, the attenuation was greater in the 24-week age group. These changes, however, were reversed by in vivo treatment with lithium chloride, a stabilizer of β-catenin, and confirmed by gain-of-function study with DEC1 transfection into DEC1 KO bone marrow mesenchymal stem cells and loss-of-function study with siDEC1 lentiviral infection into the corresponding WT cells.

CONCLUSION

DEC1 is a positive regulator with a broad activity spectrum in both bone development and maintenance, and the osteopenic phenotype accelerated by DEC1 deficiency is achieved by enhanced DKK1 activity and attenuated PI3KCA/Akt/GSK3β signaling.

EFFECT OF ADDING HOME-BASED MODERATE-INTENSITY EXERCISE ON METABOLIC FUNCTIONS IN OLDER ADULTS WITH NON-COMMUNICABLE DISEASES WHO REGULARLY PERFORM GYM-BASED MODERATE-INTENSITY EXERCISE

CONTEXT

Physical activity is important for the management of metabolic functions; however, little is known whether performing home-based moderate-intensity exercise (MIE) obtains further improvement on metabolic functions in adults with non-communicable diseases (NCDs) who already perform regular gym-based MIE.

OBJECTIVE

The purpose of this study was to examine the effect of adding home-based MIE on metabolic functions in older adults with NCDs who have regularly performed gym-based MIE.

DESIGN

This was a single-center randomized controlled study. The observation period was set for 24 weeks.

SUBJECTS AND METHODS

Twenty-one older adults (age, 60-79 years) with uncomplicated NCDs, who have performed 30-40 min MIE, 2-3 days/week at a hospital gym for over 1 year, were randomly divided into two groups: performing home-based MIE, comprising aerobic and resistance exercises, at least 20 min/day, 3 days/week (HOME, n = 11), or not performing home-based MIE (CON, n = 10). All participants completed the study and continued their gym-based MIE as usual.

RESULTS

After 24 weeks, there were no significant differences in the values of any outcomes. Conversely, the decrease in waist circumference (WC) was larger in the HOME group (-2.17 [-3.98, -0.36] cm) than in the CON group (0.57 [-1.42, 2.56] cm) (p < 0.05), although not in other outcomes.

CONCLUSIONS

Although further studies are needed, we found that adding home-based MIE had a positive effect on WC, but little effect on other metabolic functions in older adults with NCDs who have continued regular gym-based MIE.

Jmjd3 Plays Pivotal Roles in the Proper Development of Early-Born Retinal Lineages: Amacrine, Horizontal, and Retinal Ganglion Cells

Purpose

Trimethylation of histone H3 at lysine 27 (H3K27me3) is a critical mediator of transcriptional gene repression, and Jmjd3 and Utx are the demethylases specific to H3K27me3. Using an in vitro retinal explant culture system, we previously revealed the role of Jmjd3 in the development of rod bipolar cells; however, the roles of Jmjd3 in the development of early-born retinal cells are unknown due to limitations concerning the use of retinal explant culture systems. In this study, we investigated the roles of Jmjd3 in the development of early-born retinal cells.

Methods

We examined retina-specific conditional Jmjd3 knockout (Jmjd3-cKO) mice using immunohistochemistry and quantitative reverse transcription PCR and JMJD3 binding to a target locus by chromatin immunoprecipitation analysis.

Results

We observed reductions in amacrine cells (ACs) and horizontal cells (HCs), as well as lowered expression levels of several transcription factors involved in the development of ACs and HCs in the Jmjd3-cKO mouse retina. JMJD3 bound the promoter regions of these transcription factors. Notably, an elevated number of retinal ganglion cells (RGCs) was observed at embryonic stages, whereas RGCs were moderately reduced at later postnatal stages in the Jmjd3-cKO retina. We also observed reduced expression of Eomes, which is required for the maintenance of RGCs, as well as lower H3K27me3 level and lower JMJD3 binding in the promoter region of Eomes in RGC-enriched cells.

Conclusions

The results indicated that Jmjd3 has critical roles in the development of early-born retinal subtypes, and suggested biphasic roles of Jmjd3 in RGC production and maintenance.

Mutant ASXL1 induces age-related expansion of phenotypic hematopoietic stem cells through activation of Akt/mTOR pathway

Somatic mutations of ASXL1 are frequently detected in age-related clonal hematopoiesis (CH). However, how ASXL1 mutations drive CH remains elusive. Using knockin (KI) mice expressing a C-terminally truncated form of ASXL1-mutant (ASXL1-MT), we examined the influence of ASXL1-MT on physiological aging in hematopoietic stem cells (HSCs). HSCs expressing ASXL1-MT display competitive disadvantage after transplantation. Nevertheless, in genetic mosaic mouse model, they acquire clonal advantage during aging, recapitulating CH in humans. Mechanistically, ASXL1-MT cooperates with BAP1 to deubiquitinate and activate AKT. Overactive Akt/mTOR signaling induced by ASXL1-MT results in aberrant proliferation and dysfunction of HSCs associated with age-related accumulation of DNA damage. Treatment with an mTOR inhibitor rapamycin ameliorates aberrant expansion of the HSC compartment as well as dysregulated hematopoiesis in aged ASXL1-MT KI mice. Our findings suggest that ASXL1-MT provokes dysfunction of HSCs, whereas it confers clonal advantage on HSCs over time, leading to the development of CH.

Dual Regulation of Histone Methylation by mTOR Complexes Controls Glioblastoma Tumor Cell Growth via EZH2 and SAM

Epigenetic regulation known for DNA methylation and histone modification is critical for securing proper gene expression and chromosomal function, and its aberration induces various pathologic conditions including cancer. Trimethylation of histone H3 on lysine 27 (H3K27me3) is known to suppress various genes related to cancer cell survival and the level of H3K27me3 may have an influence on tumor progression and malignancy. However, it remains unclear how histone methylation is regulated in response to genetic mutation and microenvironmental cues to facilitate the cancer cell survival. Here, we report a novel mechanism of the specific regulation of H3K27me3 by cooperatively two mTOR complexes, mTORC1 and mTORC2 in human glioblastoma (GBM). Integrated analyses revealed that mTORC1 upregulates the protein expression of enhancer of zeste homolog 2, a main component of polycomb repressive complex 2 which is known as H3K27-specific methyltransferase. The other mTOR complex, mTORC2, regulates production of S-adenosylmethionine, an essential substrate for histone methylation. This cooperative regulation causes H3K27 hypermethylation which subsequently promotes tumor cell survival both in vitro and in vivo xenografted mouse tumor model. These results indicate that activated mTORC1 and mTORC2 complexes cooperatively contribute to tumor progression through specific epigenetic regulation, nominating them as an exploitable therapeutic target against cancer. IMPLICATIONS: A dynamic regulation of histone methylation by mTOR complexes promotes tumor growth in human GBM, but at the same time could be exploitable as a novel therapeutic target against this deadly tumor.

H3K27me3 demethylase UTX regulates the differentiation of a subset of bipolar cells in the mouse retina

Di- and trimethylation of lysine 27 on histone 3 (H3K27me2/3) is a critical gene repression mechanism. We previously showed that down-regulation of the H3K27 demethylase, Jumonji domain-containing protein 3 (JMJD3), resulted in a reduced number of protein kinase C (PKC)α-positive rod ON-bipolar cells. In this work, we focused on the role of another H3K27 demethylase, ubiquitously transcribed tetratricopeptide repeat X chromosome (UTX), in retinal development. UTX was expressed in the retinal progenitor cells of the embryonic mouse retina and was observed in the inner nuclear layer during late retinal development and in the mature retina. The short hairpin RNA-mediated knockdown of Utx in a mouse retinal explant led to a reduced number of PKCα-positive rod ON-bipolar cells. However, other retinal subtypes were unaffected by this knockdown. Using a retina-specific knockout of Utx in mice, the in vivo effects of UTX down-regulation were examined. Again, the number of PKCα-positive rod ON-bipolar cells was reduced, and no other apparent phenotypes, including retinal progenitor proliferation, apoptosis or differentiation, were observed. Finally, we examined retina-specific Utx and Jmjd3 double-knockout mice and found that although the number of rod ON-bipolar cells was reduced, no additional effects from the loss of Utx and Jmjd3 were observed. Taken together, our data show that UTX contributes to retinal differentiation in a lineage-specific manner.

Kdm6a Deficiency Activates Inflammatory Pathways, Promotes M2 Macrophage Polarization, and Causes Bladder Cancer in Cooperation with p53 Dysfunction

PURPOSE

Epigenetic deregulation is deeply implicated in the pathogenesis of bladder cancer. KDM6A (Lysine (K)-specific demethylase 6A) is a histone modifier frequently mutated in bladder cancer. However, the molecular mechanisms of how KDM6A deficiency contributes to bladder cancer development remains largely unknown. We hypothesized that clarification of the pathogenic mechanisms underlying KDM6A-mutated bladder cancer can help in designing new anticancer therapies.

EXPERIMENTAL DESIGN

We generated mice lacking Kdm6a in the urothelium and crossed them with mice heterozygous for p53, whose mutation/deletion significantly overlaps with the KDM6A mutation in muscle-invasive bladder cancer (MIBC). In addition, BBN (N-butyl-N-(4-hydroxybutyl) nitrosamine), a cigarette smoke-like mutagen, was used as a tumor-promoting agent. Isolated urothelia were subjected to phenotypic, pathologic, molecular, and cellular analyses. The clinical relevance of our findings was further analyzed using genomic and clinical data of patients with MIBC.

RESULTS

We found that Kdm6a deficiency activated cytokine and chemokine pathways, promoted M2 macrophage polarization, increased cancer stem cells and caused bladder cancer in cooperation with p53 haploinsufficiency. We also found that BBN treatment significantly enhanced the expression of proinflammatory molecules and accelerated disease development. Human bladder cancer samples with decreased KDM6A expression also showed activated proinflammatory pathways. Notably, dual inhibition of IL6 and chemokine (C-C motif) ligand 2, upregulated in response to Kdm6a deficiency, efficiently suppressed Kdm6a-deficient bladder cancer cell growth.

CONCLUSIONS

Our findings provide insights into multistep carcinogenic processes of bladder cancer and suggest molecular targeted therapeutic approaches for patients with bladder cancer with KDM6A dysfunction.

Loss of Endothelium-Derived Wnt5a Is Associated With Reduced Pericyte Recruitment and Small Vessel Loss in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a life-threatening disorder of the pulmonary circulation associated with loss and impaired regeneration of microvessels. Reduced pericyte coverage of pulmonary microvessels is a pathological feature of PAH and is caused partly by the inability of pericytes to respond to signaling cues from neighboring pulmonary microvascular endothelial cells (PMVECs). We have shown that activation of the Wnt/planar cell polarity pathway is required for pericyte recruitment, but whether production and release of specific Wnt ligands by PMVECs are responsible for Wnt/planar cell polarity activation in pericytes is unknown.

METHODS

Isolation of pericytes and PMVECs from healthy donor and PAH lungs was carried out with 3G5 or CD31 antibody-conjugated magnetic beads. Wnt expression profile of PMVECs was documented via quantitative polymerase chain reaction with a Wnt primer library. Exosome purification from PMVEC media was carried out with the ExoTIC device. Hemodynamic profile, right ventricular function, and pulmonary vascular morphometry were obtained in a conditional endothelium-specific Wnt5a knockout ( Wnt5a^ECKO) mouse model under normoxia, chronic hypoxia, and hypoxia recovery.

RESULTS

Quantification of Wnt ligand expression in healthy PMVECs cocultured with pericytes demonstrated a 35-fold increase in Wnt5a, a known Wnt/planar cell polarity ligand. This Wnt5a spike was not seen in PAH PMVECs, which correlated with an inability to recruit pericytes in Matrigel coculture assays. Exosomes purified from media demonstrated an increase in Wnt5a content when healthy PMVECs were cocultured with pericytes, a finding that was not observed in exosomes of PAH PMVECs. Furthermore, the addition of either recombinant Wnt5a or purified healthy PMVEC exosomes increased pericyte recruitment to PAH PMVECs in coculture studies. Although no differences were noted in normoxia and chronic hypoxia, Wnt5a^ECKO mice demonstrated persistent pulmonary hypertension and right ventricular failure 4 weeks after recovery from chronic hypoxia, which correlated with significant reduction, muscularization, and decreased pericyte coverage of microvessels.

CONCLUSIONS

We identify Wnt5a as a key mediator for the establishment of pulmonary endothelium-pericyte interactions, and its loss could contribute to PAH by reducing the viability of newly formed vessels. We speculate that therapies that mimic or restore Wnt5a production could help prevent loss of small vessels in PAH.

The loss of dopaminergic neurons in DEC1 deficient mice potentially involves the decrease of PI3K/Akt/GSK3β signaling

Here we study the effects of differentiated embryonic chondrocyte gene 1(DEC1) deficiency on midbrain dopaminergic(DA) neurons in the substantia nigra pars compacta(SNpc) through behavioral, histological and molecular analysis. We have found that compared to the age-matched WT mice, DEC1 deficient mice show a decrease in locomotor activity and motor coordination, which shows the main features of Parkinson's disease(PD). But there is no significant difference in spatial learning and memory skills between WT and DEC1 KO mice. Compared to the age-matched WT mice, DEC1 deficient mice exhibit the loss of DA neurons in the SNpc and reduction of dopamine and its metabolites in the striatum. The activated caspase-3 and TH/TUNEL⁺ cells increase in the SNpc of 6- and 12-month-old DEC1 KO mice compared to those of the age-matched WT mice. But we haven't found any NeuN/TUNEL⁺ cell increase in the hippocampus of the above two types of mice at the age of 6 months. Furthermore, DEC1 deficiency leads to a significant inhibition of PI3K/Akt/GSK3β signaling pathway. Additionally, LiCl could rescue the DA neuron loss of midbrain in the 6-month-old DEC1 KO mice. Taken together, the loss of DA neurons in the DEC1 deficient mice potentially involves the downregulation of PI3K/Akt/GSK3β signaling.

Accumulation of versican facilitates wound healing: Implication of its initial ADAMTS-cleavage site

Versican is a large chondroitin sulfate/dermatan sulfate proteoglycan in the extracellular matrix, and is expressed at high levels in tissues during development and remodeling in pathological conditions. Its core protein is cleaved at a region close to the N-terminal end of CSβ domain by several members of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, i.e., ADAMTS-1, 4, 5, 9, 15, and 20. Here, using a CRISPR/Cas9 system, we generated knock-in mice (V1R), which express an ADAMTS cleavage-resistant versican. Some V1R homozygote mice, termed R/R, exhibit syndactyly and organ hemorrhage. In wound healing experiments, R/R wound shows accumulation of versican and activated TGFβ-signaling in the early stage, leading to faster healing than wild type wound. Immunostaining for Ki67, CD31, smooth muscle α-actin, periostin demonstrates higher levels of overall cell proliferation and an increased number of endothelial cells and myofibroblasts. Immunostaining for CD11b and qRT-PCR for macrophage markers revealed increased levels of inflammatory cell infiltration, especially those of M1 macrophages. Cultured R/R dermal fibroblasts revealed increased deposition of versican, type I and III collagens, and hyaluronan, and upregulation of Smad2/3 signaling. Taken together, these results demonstrate that the cleavage site determines versican turnover and that versican plays a central role in the provisional matrix during the wound repair.

Mechanical regulation of bone homeostasis through p130Cas-mediated alleviation of NF-κB activity

Mechanical loading plays an important role in bone homeostasis. However, molecular mechanisms behind the mechanical regulation of bone homeostasis are poorly understood. We previously reported p130Cas (Cas) as a key molecule in cellular mechanosensing at focal adhesions. Here, we demonstrate that Cas is distributed in the nucleus and supports mechanical loading-mediated bone homeostasis by alleviating NF-κB activity, which would otherwise prompt inflammatory processes. Mechanical unloading modulates Cas distribution and NF-κB activity in osteocytes, the mechanosensory cells in bones. Cas deficiency in osteocytes increases osteoclastic bone resorption associated with NF-κB-mediated RANKL expression, leading to osteopenia. Upon shear stress application on cultured osteocytes, Cas translocates into the nucleus and down-regulates NF-κB activity. Collectively, fluid shear stress-dependent Cas-mediated alleviation of NF-κB activity supports bone homeostasis. Given the ubiquitous expression of Cas and NF-κB together with systemic distribution of interstitial fluid, the Cas-NF-κB interplay may also underpin regulatory mechanisms in other tissues and organs.

Differences between primary central nervous system lymphoma and glioblastoma: topographic analysis using voxel-based morphometry

AIM

To evaluate the diagnostic feasibility of probabilistic analysis using voxel-based morphometry (VBM) in differentiating primary central nervous system lymphoma (PCNSL) from glioblastoma (GBM).

MATERIALS AND METHODS

In total, 118 patients with GBM (57 males, 61 females; mean [± standard deviation] age, 56.9±19.3 years; median, 61 years) and 52 patients with PCNSL (37 males, 15 females; mean age, 62±13.3 years, median, 66 years) were studied retrospectively. Each patient underwent preoperative contrast-enhanced T1-weighted imaging (CE-T1WI) using a 1.5 or 3 T magnetic resonance imaging (MRI) system. To assess preferential occurrence sites, images from CE-T1WI were co-registered and spatially normalised using the MNI152 T1 template. Subsequently, a region of interest (ROI) was placed in the centre of the enhancing tumour in normalised images with 1-mm isotropic resolution. The same ROI between normalised and T1 template images was set up using an ROI manager function in ImageJ software. A spherical volume of interest (VOI) with a radius of 10 mm was determined. A probability map was created by overlaying each image with the VOI. Each VOI was removed from T1 template images for VBM analysis. VBM analysis was performed using statistical parametric mapping (SPM) 12 software under default settings.

RESULTS

VBM analysis showed significantly higher frequency in the splenium of the corpus callosum among PCNSL patients than among GBM patients (p<0.05; family-wise error correction).

CONCLUSION

Topographic analysis using VBM provides useful information for differentiating PCNSL from GBM.

Intravoxel Incoherent Motion MR Imaging of Pediatric Intracranial Tumors: Correlation with Histology and Diagnostic Utility

BACKGROUND AND PURPOSE

Intravoxel incoherent motion imaging, which simultaneously measures diffusion and perfusion parameters, is promising for brain tumor grading. However, intravoxel incoherent motion imaging has not been tested in children. The purpose of this study was to evaluate the correlation between intravoxel incoherent motion parameters and histology to assess the accuracy of intravoxel incoherent motion imaging for pediatric intracranial tumor grading.

MATERIALS AND METHODS

Between April 2013 and September 2015, 17 children (11 boys, 6 girls; 2 months to 15 years of age) with intracranial tumors were included in this retrospective study. Intravoxel incoherent motion parameters were fitted using 13 b-values for a biexponential model. The perfusion-free diffusion coefficient, pseudodiffusion coefficient, and perfusion fraction were measured in high- and low-grade tumors. These intravoxel incoherent motion parameters and the ADC were compared using the unpaired t test. The correlations between the intravoxel incoherent motion parameters and microvessel density or the MIB-1 index were analyzed using the Spearman correlation test. Receiver operating characteristic analysis was used to evaluate diagnostic performance.

RESULTS

The perfusion-free diffusion coefficient and ADC were lower in high-grade than in low-grade tumors (perfusion-free diffusion coefficient, 0.85 ± 0.40 versus 1.53 ± 0.21 × 10^-3 mm²/s, P < .001; ADC, 1.04 ± 0.33 versus 1.60 ± 0.21 × 10^-3 mm²/s, P < .001). The pseudodiffusion coefficient showed no difference between the groups. The perfusion fraction was higher in high-grade than in low-grade tumors (21.7 ± 8.2% versus 7.6 ± 4.3%, P < .001). Receiver operating characteristic analysis found that the combined perfusion-free diffusion coefficient and perfusion fraction had the best diagnostic performance for tumor differentiation (area under the curve = 0.986).

CONCLUSIONS

Intravoxel incoherent motion imaging reflects tumor histology and may be a helpful, noninvasive method for pediatric intracranial tumor grading.

Paradoxical counteraction by imatinib against cell death in myeloid progenitor 32D cells expressing p210BCR-ABL

Chronic myeloid leukemia (CML) is believed to be caused by the tyrosine kinase p210BCR-ABL, which exhibits growth-promoting and anti-apoptotic activities. However, mechanisms that allow cell differentiation in CML still remain elusive. Here we established tetracycline (Tet)-regulatable p210BCR-ABL-expressing murine 32D myeloid progenitor (32D/TetOff-p210) cells to explore p210BCR-ABL-induced cell death and differentiation. Tet-regulatable overexpression of p210BCR-ABL induced cell death due to the activation of both caspase-1 and caspase-3, coincident with the differentiation from myeloid progenitors into CD11b⁺Ly6C⁺Ly6G⁺ cells with segmented nuclei, exemplified as granulocytic myeloid-derived suppressor cells (G-MDSC), and the ability to secrete IL-1β, TNF-α, and S100A8/A9 into the culture supernatant. Treatment with imatinib almost completely abrogated all these phenotypes. Moreover, overexpression of a sensor of activated caspase-1 based on fluorescence resonance energy transfer (FRET) probe enabled us to detect activation of caspase-1 in a human CML cell line, K562. Furthermore, increased numbers of splenic G-MDSC associated with enhancement of S100A8/A9 production were observed in transgenic mice expressing p210BCR-ABL compared with that in wild-type mice. We also propose the novel mode of cell death in this 32D/TetOff-p210 system termed as myeloptosis.

A Qualitative and Quantitative Correlation Study of Lumbar Intervertebral Disc Degeneration Using Glycosaminoglycan Chemical Exchange Saturation Transfer, Pfirrmann Grade, and T1-ρ

BACKGROUND AND PURPOSE

Glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging allows the direct measurement and mapping of glycosaminoglycans. In this study, we aimed to evaluate the usefulness of gagCEST imaging in the quantitative assessment of intervertebral disc degeneration in a comparison with Pfirrmann grade and T1-ρ measurements.

MATERIALS AND METHODS

Ninety-six lumbar intervertebral discs in 24 volunteers (36.0 ± 8.5 years of age, 21 men and 3 women) were examined with both gagCEST imaging and T1-ρ measurements. The gagCEST imaging was performed at 3T with a saturation pulse with 1.0-second duration and the B₁ amplitude of 0.8 μT followed by imaging by a 2D fast spin-echo sequence. The Z-spectra were obtained at 25 frequency offsets from -3 to +3 ppm (step, 0.25 ppm). A point-by-point B₀ correction was performed with a B₀ map. The gagCEST signal and T1-ρ values were measured in the nucleus pulposus in each intervertebral disc. The Pfirrmann grades were assessed on T2-weighted images.

RESULTS

The gagCEST signal at grade I (5.36% ± 2.79%) was significantly higher than those at Pfirrmann grade II (3.15% ± 1.40%, P = .0006), grade III (0.14% ± 1.03%, P < .0001), grade IV (-1.75% ± 2.82%, P < .0001), and grade V (-1.47% ± 0.36%, P < .0001). The gagCEST signal at grade II was significantly higher than those of grade III (P < .0001), grade IV (P < .0001), and grade V (P < .0001). The gagCEST signal was significantly correlated negatively with Pfirrmann grade (P < .0001) and positively correlated with T1-ρ (P < .0001).

CONCLUSIONS

GagCEST imaging could be a reliable and quantitative technique for assessing intervertebral disc degeneration.