👤 Kei Hori

Methylprednisolone (mPSL) pulse therapy is an essential treatment for systemic lupus erythematosus (SLE); however, it carries a risk of osteonecrosis of the femoral head (ONFH). The pathogenesis of ONFH involves neutrophil extracellular trap (NET)-mediated microcirculation disorders. In BALB/c mice with imiquimod (IMQ)-induced lupus, mPSL pulse elevated serum levels of prenylcysteine oxidase 1 (PCYOX1), an enzyme that produces NET inducers hydrogen peroxide and farnesal, resulting in increased NETs in vivo. Although ischemia was observed in the femoral head, IMQ + mPSL-treated BALB/c mice did not develop ONFH. PCYOX1 is abundant in very-low-density lipoproteins. This study aimed to demonstrate that hyperlipidemia exacerbates NET-mediated microcirculation disorders and leads to ONFH development following mPSL pulse in lupus mice. To address this, ApoE mutant hyperlipidemic and BALB/c mice with IMQ-induced lupus received mPSL pulse. NET-forming neutrophils in peripheral blood were detected by flow cytometry. ONFH was assessed microscopically. As a result, IMQ + mPSL-treated ApoE mutant but not BALB/c mice developed ONFH, exhibiting higher levels of PCYOX1 and NET-forming neutrophils in circulation. In addition, NET-forming neutrophils accumulated in the vessels surrounding the femoral head, accompanied by osteocyte necrosis. This study demonstrated that mPSL pulse in lupus mice with hyperlipidemia enhanced PCYOX1 levels and NET formation, resulting in ONFH development, suggesting that hyperlipidemia may be a risk factor for ONFH following mPSL pulse therapy in SLE. Show less

Familial hypercholesterolemia (FH) is characterized by high serum low-density lipoprotein cholesterol (LDL-C) levels from birth, tendon/skin xanthomas, and premature coronary artery disease. The prevalence of FH is 1 per 300 individuals in the general population. FH is caused by a pathogenic (rare) variant in the LDL receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. In Japan, there has been only one reported case of a family with FH caused by the known APOB p.(Arg3527Gln) variant. Those without pathogenic variants in the LDLR or PCSK9 genes account for approximately 36% of patients with FH. Novel causative genes/variants of FH have been explored in patients with FH worldwide, but no gene variants with a large effect size have been found. Polygenic hypercholesterolemia accounts for approximately 10% of patients with clinical FH. We performed whole-exome sequencing in 122 families without pathogenic variants in the LDLR and PCSK9 genes. However, we could not find novel causative genes/variants of FH via family analysis. We examined all the APOB variants and showed that the low-frequency APOB p.(Pro955Ser) variant has a moderate effect size in FH patients via functional analysis of hepatocytes. We also reported that low-frequency PCSK9 variants contribute to the severity of the FH phenotype in patients with FH harboring an LDLR pathogenic variant. Thus, the combination of low-frequency variants and age, environmental factors such as diet, or other genetic factors contribute to the severity of or variability in the FH phenotype. Show less

Familial hypercholesterolemia (FH) causes corneal arcus (CA) and xanthomas via lipid particle deposition. Lipoprotein(a) [Lp(a)] consists of an apolipoproteinB100 and apolipoprotein(a). As apolipoprotein(a) accumulates within extracellular connective tissues, it may associate with CA and tendon xanthoma. To elucidate the association between elevated Lp(a) and FH-related physical features and evaluate their independent and joint prognostic utility on cardiovascular risk. We retrospectively analyzed 484 clinically diagnosed FH patients, evaluating both Lp(a) and physical features. Physical features were compared in individuals with and without Lp(a) ≥ 30 mg/dL. The occurrence of major adverse cardiovascular events (MACE = cardiovascular death + acute coronary syndrome + ischemic stroke) was compared in those stratified according to Lp(a) ≥ 30 mg/dL and physical features. The median value of Lp(a) was 18.4 mg/dL; subjects with Lp(a) ≥ 30 mg/dL were more likely to exhibit CA and greater Achilles tendon thickness (ATT). Receiver operating characteristic analysis suggested 14.0 mm as an optimal cut-off value of ATT predicting Lp(a) ≥ 30 mg/dL (C-statistic = 0.58). Even after adjusting for age, sex, untreated low-density lipoprotein cholesterol level, and FH-related pathogenic variants, the co-existence of CA and ATT ≥ 14.0 mm was independently associated with Lp(a) ≥30 mg/dL (odds ratio = 2.31; 95% CI = 1.22-4.38; P = .010). During a 15-year observational period (median = 1835 days), MACE occurred more frequently in subjects with Lp(a) ≥ 30 mg/dL (log-rank P = .026). This Lp(a)-associated cardiovascular risk was further elevated among those with both CA and ATT ≥ 14.0 mm (log-rank P = .042), whereas the presence of physical stigmata did not worsen cardiovascular outcome when Lp(a) was < 30 mg/dL. Assessment of CA and ATT in FH identifies those more likely to have higher Lp(a) levels. The presence of these triads is associated with the highest risk of MACE and potentially guides intensification of antiatherosclerotic therapies. Show less

Extracellular tau has been highlighted in the pathogenesis of Alzheimer disease (AD), which is the most common neurodegenerative disease. Pathological analyses as well as model animal studies suggest that amyloid-β peptide (Aβ) deposition facilitates the spreading of tau aggregation pathology via extracellular tau. However, the precise mechanism of tau secretion remains unknown. Here, we show that the overexpression of amyloid precursor protein (APP) enhances the secretion of tau phosphorylated at threonine 181 in mouse neuroblastoma Neuro2a cells. Moreover, we found that soluble amyloid precursor protein β (sAPPβ), which is generated by β-site APP cleaving enzyme 1 (BACE1), mediates tau secretion. Our results demonstrate that BACE1-mediated cleavage of APP plays pathological roles in AD pathogenesis by not only Aβ production, but by the spreading of tau aggregation pathology via sAPPβ in AD patients. Show less

Primary chylomicronemia (PCM) is a rare and intractable disease characterized by marked accumulation of chylomicrons in plasma. The levels of plasma triglycerides (TGs) typically range from 1,000 - 15,000 mg/dL or higher.PCM is caused by defects in the lipoprotein lipase (LPL) pathway due to genetic mutations, autoantibodies, or unidentified causes. The monogenic type is typically inherited as an autosomal recessive trait with loss-of-function mutations in LPL pathway genes (LPL, LMF1, GPIHBP1, APOC2, and APOA5). Secondary/environmental factors (diabetes, alcohol intake, pregnancy, etc.) often exacerbate hypertriglyceridemia (HTG). The signs, symptoms, and complications of chylomicronemia include eruptive xanthomas, lipemia retinalis, hepatosplenomegaly, and acute pancreatitis with onset as early as in infancy. Acute pancreatitis can be fatal and recurrent episodes of abdominal pain may lead to dietary fat intolerance and failure to thrive.The main goal of treatment is to prevent acute pancreatitis by reducing plasma TG levels to at least less than 500-1,000 mg/dL. However, current TG-lowering medications are generally ineffective for PCM. The only other treatment options are modulation of secondary/environmental factors. Most patients need strict dietary fat restriction, which is often difficult to maintain and likely affects their quality of life.Timely diagnosis is critical for the best prognosis with currently available management, but PCM is often misdiagnosed and undertreated. The aim of this review is firstly to summarize the pathogenesis, signs, symptoms, diagnosis, and management of PCM, and secondly to propose simple diagnostic criteria that can be readily translated into general clinical practice to improve the diagnostic rate of PCM. In fact, these criteria are currently used to define eligibility to receive social support from the Japanese government for PCM as a rare and intractable disease.Nevertheless, further research to unravel the molecular pathogenesis and develop effective therapeutic modalities is warranted. Nationwide registry research on PCM is currently ongoing in Japan with the aim of better understanding the disease burden as well as the unmet needs of this life-threatening disease with poor therapeutic options. Show less

The prognosis of patients with high-grade or advanced-stage endometrial cancer remains poor. As cancer stem-like cells (CSCs) are thought to be associated with endometrial cancers, it is essential to investigate the molecular mechanisms that regulate endometrial CSCs. Dual-specificity phosphatase 6 (DUSP6) functions as a negative-feedback regulator of MAPK-ERK1/2 signaling, but its role in endometrial cancer remains unknown. We investigated whether DUSP6 is involved in cancer cell stemness using endometrial cancer cell lines and specimens from endometrial cancer patients. DUSP6 induced the expression of CSC-related genes including ALDH1, Nanog, SOX2 and Oct4A, increased the population of cells in the G0/G1 phase, and promoted sphere formation ability. DUSP6 knockdown resulted in reduced cell invasion and metastasis, whereas DUSP6 overexpression inhibited apoptosis under serum-free conditions. Moreover, DUSP6 decreased phosphorylated ERK1/2 and increased phosphorylated Akt levels, which potentially induces CSC features. In patients with endometrial cancers, DUSP6 expression was determined using immunohistochemistry, and based on the results, the patients were dichotomized into high- and low-DUSP6-expression groups. Progression-free survival and overall survival were significantly shorter in the high-DUSP6-expression group. These results suggest that DUSP6 has potential value as a biomarker of CSCs and as a target of therapies designed to eliminate CSCs in endometrial cancer. Show less

The establishment of axon-dendrite polarity is fundamental for radial migration of neurons during cortex development of mammals. We demonstrate that the E3 ubiquitin ligases WW-Containing Proteins 1 and 2 (Wwp1 and Wwp2) are indispensable for proper polarization of developing neurons. We show that knockout of Wwp1 and Wwp2 results in defects in axon-dendrite polarity in pyramidal neurons, and their aberrant laminar cortical distribution. Knockout of miR-140, encoded in Wwp2 intron, engenders phenotypic changes analogous to those upon Wwp1 and Wwp2 deletion. Intriguingly, transcription of the Wwp1 and Wwp2/miR-140 loci in neurons is induced by the transcription factor Sox9. Finally, we provide evidence that miR-140 supervises the establishment of axon-dendrite polarity through repression of Fyn kinase mRNA. Our data delineate a novel regulatory pathway that involves Sox9-[Wwp1/Wwp2/miR-140]-Fyn required for axon specification, acquisition of pyramidal morphology, and proper laminar distribution of cortical neurons. Show less

Hyperglycemia induces nonconcordant regulation of renal mitochondrial respiratory complexes, increases oxidative stress, and causes diabetic nephropathy. Hypertension is a complication associated with diabetes and involves glomerular hyperfiltration, the effects of which on mitochondrial respiratory complexes are not well understood. To investigate the effect of glomerular hyperfiltration on renal mitochondrial respiratory complexes, we used the 5/6 nephrectomized BKS. Cg-Dock7 Show less

Growth hormone transgenic (GHTg) Atlantic salmon (Salmo salar) have enhanced growth when compared to their non-transgenic counterparts, and this trait can be beneficial for aquaculture production. Biological confinement of GHTg Atlantic salmon may be achieved through the induction of triploidy (3N). The growth rates of triploid GH transgenic (3NGHTg) Atlantic salmon juveniles were found to significantly vary between families in the AquaBounty breeding program. In order to characterize gene expression associated with enhanced growth in juvenile 3NGHTg Atlantic salmon, a functional genomics approach (32K cDNA microarray hybridizations followed by QPCR) was used to identify and validate liver transcripts that were differentially expressed between two fast-growing 3NGHTg Atlantic salmon families (AS11, AS26) and a slow-growing 3NGHTg Atlantic salmon family (AS25); juvenile growth rate was evaluated over a 45-day period. Of 687 microarray-identified differentially expressed features, 143 (116 more highly expressed in fast-growing and 27 more highly expressed in slow-growing juveniles) were identified in the AS11 vs. AS25 microarray study, while 544 (442 more highly expressed in fast-growing and 102 more highly expressed in slow-growing juveniles) were identified in the AS26 vs. AS25 microarray study. Forty microarray features (39 putatively associated with fast growth and 1 putatively associated with slow growth) were present in both microarray experiment gene lists. The expression levels of 15 microarray-identified transcripts were studied using QPCR with individual RNA samples to validate microarray results and to study biological variability of transcript expression. The QPCR results agreed with the microarray results for 12 of 13 putative fast-growth associated transcripts, but QPCR did not validate the microarray results for 2 putative slow-growth associated transcripts. Many of the 39 microarray-identified genes putatively associated at the transcript expression level with fast-growing 3NGHTg salmon juveniles (including APOA1, APOA4, B2M, FADSD6, FTM, and GAPDH) are involved in metabolism, iron homeostasis and oxygen transport, and immune- or stress-related responses. The results of this study increase our knowledge of family-specific impacts on growth rate and hepatic gene expression in juvenile 3NGHTg Atlantic salmon. In addition, this study provides a suite of putative rapid growth rate-associated transcripts that may contribute to the development of molecular markers [e.g. intronic, exonic or regulatory region single nucleotide polymorphisms (SNPs)] for the selection of GHTg Atlantic salmon broodstock that can be utilized to produce sterile triploids of desired growth performance for future commercial applications. Show less

Evasion of apoptosis, which enables cells to survive and proliferate under metabolic stress, is one of the hallmarks of cancer. We have recently reported that SH3GLB1/Bif-1 functions as a haploinsufficient tumor suppressor to prevent the acquisition of apoptosis resistance and malignant transformation during Myc-driven lymphomagenesis. SH3GLB1 is a membrane curvature-inducing protein that interacts with BECN1 though UVRAG and regulates the post-Golgi trafficking of membrane-integrated ATG9A for autophagy. At the premalignant stage, allelic loss of Sh3glb1 enhances Myc-induced chromosomal instability and results in the upregulation of anti-apoptotic proteins, including MCL1 and BCL2L1. Notably, we found that Sh3glb1 haploinsufficiency increases mitochondrial mass in overproliferated prelymphomatous Eμ-Myc cells. Moreover, loss of Sh3glb1 suppresses autophagy-dependent mitochondrial clearance (mitophagy) in PARK2/Parkin-expressing mouse embryonic fibroblasts (MEFs) treated with the mitochondrial uncoupler CCCP. Interestingly, PARK2-expressing Sh3glb1-deficient cells accumulate ER-associated immature autophagosome-like structures after treatment with CCCP. Taken together, we propose a model of mitophagy in which SH3GLB1 together with the class III phosphatidylinositol 3-kinase complex II (PIK3C3CII) (PIK3R4-PIK3C3-BECN1-UVRAG) regulates the trafficking of ATG9A-containing Golgi-derived membranes (A9(+)GDMs) to damaged mitochondria for autophagosome formation to counteract oncogene-driven tumorigenesis. Show less

The genetic pathways of aggressive changes of bone tumors are still poorly understood. It is very important to analyze DNA copy number alterations (DCNAs), to identify the molecular events in the step of progression to the aggressive change of bone tissue. Genome-wide array-based comparative genomic hybridization (array CGH) was used to investigate DCNAs of 14 samples from 13 aggressive bone tumors, such as giant cell tumors (GCTs) and osteosarcoma (OS), etc. Primary aggressive bone tumors had copy number gains of 17.8±12.7% in the genome, and losses of 17.3±11.4% in 287 target clones (threshold for each DCNA: ≦085, 1.15≦). Genetic unstable cases, which were defined by the total DCNAs aberration ≧30%, were identified in 9 of 13 patients (3 of 7 GCTs and all malignant tumors). High-level amplification of TGFβ2, CCND3, WI-6509, SHGC-5557, TCL1A, CREBBP, HIC1, THRA, AFM217YD10, LAMA3, RUNX1 and D22S543, were commonly observed in aggressive bone tumors. On the other hand, NRAS, D2S447, RAF1, ROBO1, MYB, MOS, FGFR2, HRAS, D13S319, D13S327, D18S552, YES1 and DCC, were commonly low. We compared genetic instability between a primary OS and its metastatic site in Case #13. Metastatic lesion showed increased 9 DCNAs of remarkable change (m/p ratio ≧1.3 folds), compared to a primary lesion. D1S214, D1S1635, EXT1, AFM137XA11, 8 M16/SP6, CCND2, IGH, 282 M15/SP6, HIC1 and LAMA3, were overexpressed. We gave attention to HIC1 (17p13.3), which was common high amplification in this series. Our results may provide several entry points for the identification of candidate genes associated with aggressive change of bone tumors. Especially, the locus 17p11-13 including HIC1 close to p53 was common high amplification in this series and review of the literature. Show less

Hereditary multiple exostoses (EXT) is an autosomal dominant disorder that is characterized by the appearance of multiple outgrowths of the long bones (exostoses) at their epiphyses. Genetical heterogeneities have segregated at least on chromosome 8, 11, and 19 and been designated EXT1, EXT2, and EXT3, respectively. Recently, the responsible genes for EXT1 and EXT2 have been isolated and appeared to define a structurally related gene family. In the present study, we have identified novel genes which share significant sequence homologies with the EXT genes. The predicted protein products of the novel EXT-related genes, EXTR and EXTR2 (for EXT-related genes 1 and 2), consist of 919 and 330 amino acid residues, respectively. These genes were transcribed ubiquitously in various tissues. Based on PCR-assisted analyses of both a human/rodent mono-chromosomal hybrid cell panel and a radiation hybrid mapping panel, EXTR1 was localized to the chromosome 8p21 region, where loss of heterozygosity has been frequently observed in various tumors, and EXTR2 was assigned to the chromosome 1p21 region, where osteopetrosis, a dominant hereditary disease of bone, has been mapped by genetic linkage analysis, implying that the protein products of these two EXT-related genes, as well as of the EXT genes, have potential tumor suppressor activity. Show less

The rare fragile site is a specific point on a chromosome that is expressed as an isochromatid gap or break under certain conditions of cell culture and is inherited in a Mendelian codominant fashion. Five folate-sensitive fragile sites were cloned, and the molecular basis of fragile site mutation was shown to be a new class of mutation, called dynamic mutation, resulting from an allelic expansion of (CCG)n repeats. The mechanism responsible for other types of rare fragile sites, i.e., distamycin A-inducible and BrdU-requiring, is unknown, although cytogenetic studies suggested that these fragile sites play a mechanistic role in breakage and recombination and may also be integration and modification sites of foreign viral DNA genomes. A distamycin A-inducible fragile site, FRA8E, is mapped to 8q24.1 in which various loci implicated in genomic instability are located. Here we identified a YAC clone spanning both FRA8E and the hereditary multiple exostosis (EXT1) gene, using fluorescence in situ hybridization (FISH) analysis of a yeast artificial chromosome (YAC) contig. By using P1 clones as probes, the FRA8E locus was further localized to a 400-kb region including the EXT1 gene. Furthermore, the integration and amplification site of human papillomavirus 16 DNA in the ASCC (argyrophil small cell carcinoma) cells were shown not to coincide with FRA8E, but to be involved in an extensively broad genomic region of 8q24.1, including the c-myc gene. Show less