👤 Kota Nakajima

Neural pathways related to total calorie intake have been extensively studied. However, it remains unclear how these mechanisms control food selection. Male mice were subjected to glucoprivation through the intraperitoneal (i.p.) administration of 2-deoxy-d-glucose (2DG) and were examined for food selection between a high-carbohydrate diet (HCD) and a high-fat diet (HFD) in a diet choice paradigm. This involved the chemogenetic or optogenetic modulation of the neural activity of AMP-activated protein kinase (AMPK)-regulated corticotropin-releasing hormone (CRH) neurons, melanocortin-4 receptor (MC4R) neurons in the paraventricular nucleus of the hypothalamus (PVH), and neuropeptide Y (NPY) neurons projecting to the PVH. Glucoprivation induced by 2DG administration in mice influenced two distinct neural pathways in the PVH that separately promote the intake of an HCD or an HFD. Injection of 2DG activated PVH-projecting NPY neurons in the nucleus of the solitary tract (NTS) and ventrolateral medulla (VLM), resulting in a rapid increase in HCD intake through stimulation of PVH AMPK-regulated CRH neurons and recovery from glucoprivation. In contrast, PVH-projecting NPY neurons in the NTS, VLM, and arcuate nucleus of the hypothalamus (ARC) promoted HFD intake by inhibiting MC4R neurons in the PVH, reflecting the strong innate preference for an HFD in mice. The ARC NPY neurons specifically promoted HFD selection. Our findings reveal a previously unrecognized mechanism for food selection between HCD and HFD during glucoprivation. Show less

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by high levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of early onset atherosclerosis. Evinacumab, an angiopoietin-like protein 3 (ANGPTL3)-inhibiting monoclonal antibody, lowers LDL-C independently of LDL receptor activity. However, its effects on other lipid-related markers remain poorly investigated in real-world clinical practice. We herein report a 54-year-old Japanese woman with genetically confirmed compound heterozygous familial hypercholesterolemia (FH) treated with evinacumab in combination with other lipid-lowering agents. Lipoprotein apheresis was continued every two weeks throughout the treatment. Serum sampling before and after evinacumab administration found that, following evinacumab initiation, LDL-C decreased from 324 to 205 mg/dL (reduction of 119 mg/dL, -36.7%) and triglycerides from 155 to 51 mg/dL (reduction of 103 mg/dL, -66.8%). Notably, atherosclerosis-related markers showed substantial reductions, with remnant-like particle cholesterol (RLP-C) decreasing from 10.5 to ＜2.0 mg/dL, small dense LDL-C (sdLDL-C) from 80.2 to 22.1 mg/dL, and malondialdehyde-modified LDL (MDA-LDL) from 105 to 87 mg/dL. Apolipoproteins (ApoB, ApoC2, ApoC3, ApoE, and ApoA5) decreased as well. No significant changes were observed in lipoprotein (a), free fatty acids, interleukin-6, or high-sensitivity C-reactive protein levels. This is the first clinical report to comprehensively evaluate the lipid-modifying effects of evinacumab in a Japanese HoFH patient. In this case, evinacumab was highly efficacious against atherosclerosis-related markers and apolipoproteins, beyond simple LDL-C reduction, suggesting additional cardiovascular benefits. These findings provide mechanistic insights that may inform therapeutic strategies for the management of HoFH. Show less

In the PEMA-FL study in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), pemafibrate was shown to significantly decrease low-density lipoprotein cholesterol (LDL-C) levels. We aimed to investigate the mechanisms of pemafibrate-induced LDL-C reduction in patients with MASLD by conducting an additional sub-analysis of the PEMA-FL study. The PEMA-FL study randomized 118 patients with MASLD to receive pemafibrate or placebo for 72 weeks. This sub-analysis examined the percentage change in LDL-C and related lipid markers by tertile of baseline LDL-C levels and the correlation between these changes in the pemafibrate group. Pemafibrate significantly decreased LDL-C levels approximately 25% (p＜0.001 at all timepoints) from baseline in the highest tertile of baseline LDL-C levels (≥ 137.5 mg/dL), with similar trends for non-high-density lipoprotein cholesterol (non-HDL-C) and apolipoprotein B (ApoB) levels. Lipoprotein (a) [Lp(a)] levels decreased only in patients with the highest baseline LDL-C levels. Regardless of the baseline LDL-C levels, pemafibrate altered the LDL particle profile (increased LDL particle size and decreased the number); reduced lathosterol, β-sitosterol, and campesterol; and increased angiopoietin-like protein 3 (ANGPTL3). The percentage change in LDL-C positively correlated with that in ApoB, non-HDL-C, Lp(a), lathosterol, β-sitosterol, and campesterol but not HDL-C and ANGPTL3. Pemafibrate reduced LDL-C, ApoB, and non-HDL-C levels in patients with MASLD, and the effect was greater in those with higher baseline LDL-C levels. Pemafibrate may clinically benefit patients with MASLD by improving LDL-C levels and the LDL particle profile. Show less

A chimeric protein of heparanase and Ig-Fc was designed as a novel tool to expand the detection of structurally heterogeneous heparan sulfate (HS) and related glycosaminoglycans. The whole mouse heparanase gene was combined with the gene segment encoding the mouse IgG1 hinge-Fc domain. A point mutation E335A was inserted to disable putative HS degradation activity. Chimeric proteins consisted of the latent form of the enzyme devoid of HS degradation activity. The chimeric proteins bound to heparin, Show less

Congenital hypogonadotropic hypogonadism (CHH) can cause delayed secondary sexual characteristics and contribute to juvenile osteoporosis, with multiple causative genes having been reported. We treated a 27-year-old man diagnosed with central hypogonadism, presenting with delayed secondary sexual characteristics and juvenile osteoporosis, using bone resorption inhibitors and testosterone therapy. Genetic testing revealed missense variants both in the fibroblast growth factor receptor 1 ( Show less

Fibroblast growth factor receptors (FGFRs) are a highly conserved family of transmembrane receptor tyrosine kinases with multiple roles in the regulation of key cellular processes. Specific FGFR mutations have been observed in several types of cancers, including gastric carcinoma and cholangiocarcinoma. Dose escalation data of 24 Japanese patients with solid tumors treated with Tasurgratinib (previously known as E7090), a potent, selective FGFR1-3 inhibitor, was reported in a phase I, first-in-human, single-center study. Based on the safety, pharmacokinetic, and pharmacodynamic profiles observed in this study, the recommended dose of 140 mg once daily was selected for the expansion part (Part 2), a multicenter expansion of the dose-finding study restricted to patients with tumors harboring FGFR gene alterations. Safety and preliminary efficacy were assessed in Part 2. Pharmacodynamic pharmacogenomic markers (serum phosphate, FGF23, and 1,25-(OH) Show less

Colorectal cancer (CRC) remains a significant global health concern, demanding a more profound comprehension of its molecular foundations for the development of improved therapeutic strategies. This study aimed to elucidate the role of protein phosphatase 6 (PP6), a member of the type 2A protein phosphatase family, in CRC. Protein phosphatase 6 functions as a heterotrimer with a catalytic subunit (PP6c), regulatory subunits (PP6Rs; PP6R1, PP6R2, and PP6R3), and scaffold subunits (ANKRD28, ANKRD44, and ANKRD52). Elevated PP6c expression has been identified in CRC tissues compared to normal mucosa, aligning with its potential involvement in CRC pathogenesis. PP6c knockdown resulted in decreased colony-forming ability and in vivo proliferation of various CRC cell lines. Transcriptome analysis revealed that PP6c knockdown resulted in altered expression of genes associated with cancer stemness. Notably, the PP6c-PP6R3 complex is a key player in regulating cancer stem cell (CSC) markers. Additionally, increased PP6c expression was observed in CSC-like cells induced by sphere formation, implicating the role of PP6c in CSC maintenance. This study highlights the role of PP6c in CRC and suggests that it is a potential therapeutic target disrupting a pathway critical for CRC progression and stem cell maintenance. Show less

Long-chain polyunsaturated fatty acids (LCPUFAs) are essential for both fetal and placental development. We characterized the FA composition and gene expression levels of FA-metabolizing enzymes in rabbit placentas. Total FA compositions from term rabbit placentas (n = 7), livers, and plasma (both n = 4) were examined: among LCPUFAs with more than three double bonds, dihomo-γ-linolenic acid (DGLA) was the most abundant (11.4 ± 0.69 %, mean ± SE), while arachidonic acid was the second-most rich component (6.90 ± 0.56 %). DGLA was barely detectable (<1 %) in livers and plasma from term rabbits, which was significantly lower than in placentas (both p < 0.0001). Compared with the liver, transcript levels of the LCPUFA-metabolizing enzymes FADS2 and ELOVL5 were 7- and 4.5-fold higher in placentas (both p < 0.05), but levels of FADS1 and ELOVL2 were significantly lower (both p < 0.01). Our results suggest a placenta-specific enzyme expression pattern and LCPUFA profile in term rabbits, which may support a healthy pregnancy. Show less

This study aims to elucidate the clinical and molecular characteristics, treatment outcomes and prognostic factors of patients with histone H3 K27-mutant diffuse midline glioma. We retrospectively analyzed 93 patients with diffuse midline glioma (47 thalamus, 24 brainstem, 12 spinal cord and 10 other midline locations) treated at 24 affiliated hospitals in the Kansai Molecular Diagnosis Network for CNS Tumors. Considering the term "midline" areas, which had been confused in previous reports, we classified four midline locations based on previous reports and anatomical findings. Clinical and molecular characteristics of the study cohort included: age 4-78 years, female sex (41%), lower-grade histology (56%), preoperative Karnofsky performance status (KPS) scores ≥ 80 (49%), resection (36%), adjuvant radiation plus chemotherapy (83%), temozolomide therapy (76%), bevacizumab therapy (42%), HIST1H3B p.K27M mutation (2%), TERT promoter mutation (3%), MGMT promoter methylation (9%), BRAF p.V600E mutation (1%), FGFR1 mutation (14%) and EGFR mutation (3%). Median progression-free and overall survival time was 9.9 ± 1.0 (7.9-11.9, 95% CI) and 16.6 ± 1.4 (13.9-19.3, 95% CI) months, respectively. Female sex, preoperative KPS score ≥ 80, adjuvant radiation + temozolomide and radiation ≥ 50 Gy were associated with favorable prognosis. Female sex and preoperative KPS score ≥ 80 were identified as independent good prognostic factors. This study demonstrated the current state of clinical practice for patients with diffuse midline glioma and molecular analyses of diffuse midline glioma in real-world settings. Further investigation in a larger population would contribute to better understanding of the pathology of diffuse midline glioma. Show less

MYD88 p.L265P mutation occurs in over 90% of Waldenström's macroglobulinemia (WM), which is characterized by lymphoplasmacytic lymphoma (LPL) with monoclonal IgM. WM requires careful diagnosis due to overlapping features with other B-cell malignancies. Bing-Neel syndrome (BNS), a rare complication of WM, involves central nervous system (CNS) invasion. This report describes two cases of morphologically low-grade B-cell lymphoma in the bone marrow accompanied by the presence of a large B-cell lymphoma in the brain and a common MYD88 p.L265P mutation, which were eventually established as BNS mimickers. Although the two components in these cases showed the same identical light-chain restriction, different immunoglobulin heavy-chain rearrangement peaks indicated distinct lymphoma stem cells for CNS and bone marrow lesions. These clinical cases emphasize the challenges in diagnosing BNS. Based on the findings, biopsy is recommended for accurate identification of the clonal relationship and MYD88 mutation status. Show less

To support in vivo and in vitro studies of intravascular triglyceride metabolism in mice, we created rat monoclonal antibodies (mAbs) against mouse LPL. Two mAbs, mAbs 23A1 and 31A5, were used to develop a sandwich ELISA for mouse LPL. The detection of mouse LPL by the ELISA was linear in concentrations ranging from 0.31 ng/ml to 20 ng/ml. The sensitivity of the ELISA made it possible to quantify LPL in serum and in both pre-heparin and post-heparin plasma samples (including in grossly lipemic samples). LPL mass and activity levels in the post-heparin plasma were lower in Gpihbp1 Show less

Obesity is recognized as an independent risk factor for abdominal aortic aneurysm (AAA). While mutations in the melanocortin-4 receptor (MC4R) gene is the most common cause of obesity caused by mutations in a single gene, the link between MC4R function and vascular disease has still remained unclear. Here, by using melanocortin-4 receptor (MC4R) deficient mice, we confirmed MC4R deficiency promotes AAA and atherosclerosis. We demonstrated the contribution of two novel factors towards vascular vulnerability in this model: leptin signaling in vascular smooth muscle cells (VSMCs) and loss of MC4R signaling in macrophages. Leptin was shown to promote vascular vulnerability via PI3K-dependent upregulation of Spp1 expression in VSMC. Additionally, Ang II-induced AAA incidence was significantly reduced when MC4R gene expression was myeloid cell-specifically rescued in MC4R deficient (MC4R Show less

Why apolipoprotein AV (APOA5) deficiency causes hypertriglyceridemia has remained unclear, but we have suspected that the underlying cause is reduced amounts of lipoprotein lipase (LPL) in capillaries. By routine immunohistochemistry, we observed reduced LPL staining of heart and brown adipose tissue (BAT) capillaries in Apoa5-/- mice. Also, after an intravenous injection of LPL-, CD31-, and GPIHBP1-specific mAbs, the binding of LPL Abs to heart and BAT capillaries (relative to CD31 or GPIHBP1 Abs) was reduced in Apoa5-/- mice. LPL levels in the postheparin plasma were also lower in Apoa5-/- mice. We suspected that a recent biochemical observation - that APOA5 binds to the ANGPTL3/8 complex and suppresses its capacity to inhibit LPL catalytic activity - could be related to the low intracapillary LPL levels in Apoa5-/- mice. We showed that an ANGPTL3/8-specific mAb (IBA490) and APOA5 normalized plasma triglyceride (TG) levels and intracapillary LPL levels in Apoa5-/- mice. We also showed that ANGPTL3/8 detached LPL from heparan sulfate proteoglycans and GPIHBP1 on the surface of cells and that the LPL detachment was blocked by IBA490 and APOA5. Our studies explain the hypertriglyceridemia in Apoa5-/- mice and further illuminate the molecular mechanisms that regulate plasma TG metabolism. Show less

Diffuse midline glioma (DMG), H3 K27M-altered, is a tumor with a poor prognosis mainly found in children. An adolescent patient presented with thalamic hemorrhage, which initially could not be diagnosed as DMG by pathological analysis. A neoplasm in the lateral ventricle close to the previous thalamic hemorrhagic lesion was detected 12 months after the hemorrhage. Thus, endoscopic resection was performed, and a diagnosis was made. Gene expression profiling demonstrated mutation in genes, such as Show less

RA is an autoimmune disease characterized by destructive polyarthritis. CD4+ T cells are pivotal to its pathogenesis, and our previous study revealed the expression of fibroblast growth factor receptor 1 (FGFR1) is modulated by MTX treatment in CD4+ T cells of RA patients; however, the roles of FGFR1 in CD4+ T cells in the pathogenesis of RA is unclear. Therefore, in this study, we aimed to characterize FGFR1-positive CD4+ T cells in RA patients. The abundance of FGFR1-positive CD4+ T cells in peripheral blood and synovium was determined. Single-cell RNA sequencing (scRNA-seq) was performed on synovial CD4+ T cells to characterize FGFR1-positive cells. In addition, T cell activation status and cytokine production were determined using flow cytometry. The percentage of FGFR1-positive CD4+ T cells in the peripheral blood was higher in RA patients than in healthy controls (P =0.0035). They were also present in the synovium of active RA patients. The results of scRNA-seq revealed that peripheral Th (Tph) cells preferentially expressed FGFR1. Additionally, these FGFR1-positive Tph cells displayed a terminal effector cell phenotype. Consistent with this finding, FGFR1-positive CD4+ T cells in peripheral blood expressed IL-21 and IFN-γ. Our study provides evidence that FGFR1 marks terminal effector Tph cells in patients with RA. Show less

Enzymes catalyzing the reduction reaction of xenobiotics are mainly members of the aldo-keto reductase (AKR) and short-chain dehydrogenase/reductase (SDR) superfamilies. The intestine, together with the liver, is responsible for first-pass effects and is an organ that determines the bioavailability of orally administered drugs. In this study, we evaluated the mRNA and protein expression levels of 12 AKR isoforms (AKR1A1, AKR1B1, AKR1B10, AKR1B15, AKR1C1, AKR1C2, AKR1C3, AKR1C4, AKR1D1, AKR1E2, AKR7A2, and AKR7A3) and 7 SDR isoforms (CBR1, CBR3, CBR4, DCXR, DHRS4, HSD11B1, and HSD17B12) in each region of the human intestine using next-generation sequencing and data-independent acquisition proteomics. At both the mRNA and protein levels, most AKR isoforms were highly expressed in the upper regions of the intestine, namely the duodenum and jejunum, and then declined toward the rectum. Among the members in the SDR superfamily, CBR1 and DHRS4 were highly expressed in the upper regions, whereas the expression levels of the other isoforms were almost uniform in all regions. Significant positive correlations between mRNA and protein levels were observed in AKR1A1, AKR1B1, AKR1B10, AKR1C3, AKR7A2, AKR7A3, CBR1, and CBR3. The mRNA level of AKR1B10 was highest, followed by AKR7A3 and CBR1, each accounting for more than 10% of the sum of all AKR and SDR levels in the small intestine. This expression profile in the human intestine was greatly different from that in the human liver, where AKR1C isoforms are predominantly expressed. SIGNIFICANCE STATEMENT: In this study comprehensively determined the mRNA and protein expression profiles of aldo-keto reductase (AKR) and short-chain dehydrogenase/reductase isoforms involved in xenobiotic metabolism in the human intestine and found that most of them are highly expressed in the upper region, where AKR1B10, AKR7A3, and CBR1 are predominantly expressed. Since the intestine is significantly involved in the metabolism of orally administered drugs, the information provided here is valuable for pharmacokinetic studies in drug development. Show less

Nabumetone, a nonsteroidal anti-inflammatory prodrug, is converted to a pharmacologically active metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA); however, it is 11-fold more efficiently converted to 4-(6-methoxy-2-naphthyl)butan-2-ol (MNBO) via a reduction reaction in human hepatocytes. The goal of this study was to identify the enzyme(s) responsible for MNBO formation from nabumetone in the human liver. MNBO formation by human liver microsomes (HLM) was 5.7-fold higher than in the liver cytosol. In a panel of 24 individual HLM samples with quantitative proteomics data, the 17β-hydroxysteroid dehydrogenase 12 (HSD17B12) protein level had the high correlation coefficient (r = 0.80, P < 0.001) among 4457 proteins quantified in microsomal fractions during MNBO formation. Recombinant HSD17B12 expressed in HEK293T cells exhibited prominent nabumetone reductase activity, and the contribution of HSD17B12 to the activity in the HLM was calculated as almost 100%. MNBO formation in HepG2 and Huh7 cells was significantly decreased by the knockdown of HSD17B12. We also examined the role of HSD17B12 in drug metabolism and found that recombinant HSD17B12 catalyzed the reduction reactions of pentoxifylline and S-warfarin, suggesting that HSD17B12 prefers compounds containing a methyl ketone group on the alkyl chain. In conclusion, our study demonstrated that HSD17B12 is responsible for the formation of MNBO from nabumetone. Together with the evidence for pentoxifylline and S-warfarin reduction, this is the first study to report that HSD17B12, which is known to metabolize endogenous compounds, such as estrone and 3-ketoacyl-CoA, plays a role as a drug-metabolizing enzyme. Show less

Lipoprotein lipase (LPL), the enzyme that carries out the lipolytic processing of triglyceride-rich lipoproteins (TRLs), is synthesized by adipocytes and myocytes and secreted into the interstitial spaces. The LPL is then bound by GPIHBP1, a GPI-anchored protein of endothelial cells (ECs), and transported across ECs to the capillary lumen. The assumption has been that the LPL that is moved into capillaries remains attached to GPIHBP1 and that GPIHBP1 serves as a platform for TRL processing. In the current studies, we examined the validity of that assumption. We found that an LPL-specific monoclonal antibody (mAb), 88B8, which lacks the ability to detect GPIHBP1-bound LPL, binds avidly to LPL within capillaries. We further demonstrated, by confocal microscopy, immunogold electron microscopy, and nanoscale secondary ion mass spectrometry analyses, that the LPL detected by mAb 88B8 is located within the EC glycocalyx, distant from the GPIHBP1 on the EC plasma membrane. The LPL within the glycocalyx mediates the margination of TRLs along capillaries and is active in TRL processing, resulting in the delivery of lipoprotein-derived lipids to immediately adjacent parenchymal cells. Thus, the LPL that GPIHBP1 transports into capillaries can detach and move into the EC glycocalyx, where it functions in the intravascular processing of TRLs. Show less

Bipolar disorder is a common mental illness occurring in approximately 1% of individuals and requires lifelong treatment. Although genetic factors are known to contribute to this disorder, the genetic architecture has not yet been completely clarified. Our initial trio-based exome sequencing study of bipolar disorder showed enrichment of de novo, loss-of-function (LOF) or protein-altering mutations in a combined group with bipolar I and schizoaffective disorders, and the identified de novo mutations were enriched in calcium-related genes. These findings suggested a role for de novo mutations in bipolar disorder. The validity of these statistical associations will be strengthened if the functional impact of the mutations on cellular function and behavior are identified. In this study, we focused on two de novo LOF mutations in calcium-related genes, EHD1 and MACF1, found in patients with bipolar disorder. We first showed that the EHD1 mutation resulted in a truncated protein with diminished effect on neurite outgrowth and inhibited endocytosis. Next, we used CRISPR/Cas9 to establish two knock-in mouse lines to model the in vivo effects of these mutations. We performed behavioral screening using IntelliCage and long-term wheel running analysis. Ehd1 mutant mice showed higher activity in the light phase. Macf1 mutant mice showed diminished attention and persistence to rewards. These behavioral alterations were similar to the phenotypes in previously proposed animal models of bipolar disorder. These findings endorse the possible role of de novo mutations as a component of the genetic architecture of bipolar disorder, which was suggested by the statistical evidence. Show less

Epithelial-mesenchymal transition (EMT) is a cellular process by which epithelial cells transform to acquire mesenchymal phenotypes. Accumulating evidence indicate the involvement of EMT in the progression of malignant diseases. Notch signaling mediates TGF-β1-induced EMT through direct transcriptional activation of Snai1. The molecular mechanism how TGF-β1 activates Notch signaling, however, remains unknown. In this study, we show a pivotal role for reactive oxygen species (ROS)-Nrf2 pathway in TGF-β1-induced Notch signaling activation and EMT development. TGF-β1 induces Nrf2 activation through ROS production. Inhibiting Nrf2 activation either by reducing ROS levels by N-acetylcysteine or by knocking down of Nrf2 by small interfering RNA attenuated both Notch signaling activation and EMT development. TGF-β1 induced the transcription of Notch4 via Nrf2-dependent promoter activation. In conclusion, our study indicates the ROS-Nrf2 pathway mediates the development of TGF-β1-induced EMT through the activation of Notch signaling. Show less

Triglyceride (TG) and cholesterol accumulation are known to occur in the liver of rats fed a histidine-excess (5%) diet, but there are few studies reporting histochemical and molecular biological analyses of the rat liver. The aim of this study was to elucidate the molecular basis of this lipid-accumulation mechanism. Lipid accumulations, tissue section images, and gene expression levels were compared in the livers of rats fed a control or histidine-excess diet for 5 wk (n=8/group). Serum levels of TGs, free fatty acids, total cholesterol, high-density lipoprotein cholesterol, glucose, albumin, and the enzyme activities of aspartate aminotransferase and alanine aminotransferase were also analyzed. In the livers of rats fed a histidine-excess diet, histochemical analyses showed what appeared to be a preliminary stage of nonalcoholic fatty liver, characterized by lipid accumulation around the central vein area and minor fibrosis. However, there were no changes in serum TG or free fatty acid levels. Quantitative PCR analyses showed the up-regulation of FAT/CD36, which is related to the uptake of fatty acids into cells, and the downregulation of two apolipoprotein genes, ApoC3 and ApoE. The mRNA levels of PPARγ, LXRα, and AMPKα in the liver were also reduced by excess histidine intake. The results of this study suggest that steatosis caused by excess histidine intake may be the result of an imbalance between lipid transport from the liver and the uptake of free fatty acids into hepatocytes. Show less

Autophagy selectively targets invading bacteria to defend cells, whereas bacterial pathogens counteract autophagy to survive in cells. The initiation of canonical autophagy involves the PIK3C3 complex, but autophagy targeting Group A Show less

We previously found downregulation of low-density lipoprotein receptor class A domain-containing protein 4 (LDLRAD4), a negative regulator of transforming growth factor (TGF)-β signaling, in glutathione S-transferase placental form (GST-P) expressing ( Show less

We have long thought that remnant lipoproteins (RLP) in plasma are significantly increased as the result of disturbed lipoprotein metabolism followed by obesity and insulin resistance. Therefore, it was believed that insulin resistance causes and enhances RLP formation. In contrast, this hypothesis states that RLP induces insulin resistance as the result of obesity associated with the excessive fat intake. The majority of plasma TG increased after fat intake is TG in RLP (RLP-TG) and the majority of postprandial RLP is VLDL remnants, not CM remnants. RLP is newly formed lipoproteins primarily for energy supply against starvation, like blood sugar after carbohydrate intake. Since RLP bearing apoE, LPL and Lp(a) function as ligands for the VLDL receptor, RLP interacts with the VLDL receptor in visceral fat adipocytes and stored as TG similar to excessive blood sugar. However, the excessive VLDL remnants induces obesity and its associated insulin resistance, which plays a major role as the initiator of metabolic domino effects, similar to blood sugar primarily serving as an energy supply to protect against starvation. Show less

To explore possible roles of heparanase in cancer-host crosstalk, we examined whether heparanase influences expression of inflammatory chemokines in colorectal cancer cells. Murine colorectal carcinoma cells incubated with heparanase upregulated MCP-1, KC, and RANTES genes and released MCP-1 and KC proteins. Heparanase-dependent production of IL-8 was detected in two human colorectal carcinoma cell lines. Addition of a heparanase inhibitor Heparastatin (SF4) did not influence MCP-1 production, while both latent and mature forms of heparanase augmented MCP-1 release, suggesting that heparanase catalytic activity was dispensable for MCP-1 production. In contrast, addition of heparin to the medium suppressed MCP-1 release in a dose-dependent manner. Similarly, targeted suppression of Ext1 by RNAi significantly suppressed cell surface expression of heparan sulfate and MCP-1 production in colon 26 cells. Taken together, it is concluded that colon 26 cells transduce the heparanase-mediated signal through heparan sulfate binding. We propose a novel function for heparanase independent of its endoglycosidase activity, namely as a stimulant for chemokine production. Show less

Jmjd1C is one of the Jmjd1 family genes that encode putative demethylases against histone H3K9 and non-histone proteins and has been proven to play an indispensable role in mouse spermatogenesis. Here, we analyzed a newly-bred transgenic mouse strain carrying a Jmjd1C loss-of-function allele in which a β-geo cassette was integrated into the intron of the Jmjd1C locus. Jmjd1C gene-trap homozygous testes exhibited malformations in postmeiotic processes and a deficiency in the long-term maintenance of undifferentiated spermatogonia. Some groups of spermatids in the homozygous testis showed abnormal organization and incomplete elongation from the first wave of spermatogenesis onwards. Moreover, histone H4K16 acetylation, which is required for the onset of chromatin remodeling, appeared to be remarkably decreased. These effects may not have been a result of the drastic decrease in gene expression related to the events but instead may have been due to the lack of interaction between JMJD1C and its partner proteins, such as MDC1 and HSP90. Additionally, significant decreases in Oct4 expression and NANOG- and OCT4-expressing spermatogonia were found in the Jmjd1C homozygous mature testis, suggesting that JMJD1C may participate in the maintenance of spermatogonial stem cell self-renewal by up-regulating Oct4 expression. These results indicate that JMJD1C has multiple functions during spermatogenesis through interactions with different partners during the spermatogenic stages. Show less

Adenosine monophosphate-activated protein kinase (AMPK) is a sensor for cellular energy status. When the cellular energy level is decreased, AMPK is activated and functions to suppress energy-consuming processes, including protein synthesis. Recently, AMPK has received attention as an attractive molecular target for cancer therapy. Several studies have revealed that the activation of AMPK by chemical stimulators, such as metformin, induces apoptosis in a variety of hematologic malignant cells. From another perspective, these results suggest that the function of AMPK is impaired in hematologic tumor cells. However, the precise mechanisms by which this impairment occurs are not well understood. In melanoma cells, oncogenic BRAF constitutively activates the extracellular signal-regulated kinase (ERK) pathway and phosphorylates liver kinase B1, an upstream activator of 5' adenosine monophosphate-activated protein kinase (AMPK), resulting in the inactivation of liver kinase B1 and AMPK. In this study, we analyzed whether ERK is involved in the suppression of AMPK activity using established and primary human leukemia cells. We found an inverse correlation between the intensity of ERK activity and the degree of AMPK activation after stimulation with either glucose deprivation or metformin. We also found that the inhibition of ERK activity by U0126 restored AMPK activation after metformin treatment. Furthermore, a combined treatment with metformin and U0126 enhanced the antileukemic activity of metformin. Importantly, metformin induced ERK activation by suppressing the protein levels of dual specificity phosphatase 6, a negative regulator of ERK. This crosstalk between AMPK and ERK could diminish the antileukemic activity of metformin. Taken together, our present observations suggest a novel therapeutic strategy for improving the efficacy of metformin in treating leukemia. Show less

Fatty acid composition is an economically important trait in meat-producing livestock. To gain insight into the molecular genetics of fatty acid desaturase (FADS) genes in pigs, we investigated the genomic structure of the porcine FADS gene family on chromosome 2. We also examined the tissue distribution of FADS gene expression. The genomic structure of FADS family in mammals consists of three isoforms FADS1, FADS2 and FADS3. However, porcine FADS cluster in the latest pig genome assembly (Sscrofa 10.2) containing some gaps is distinct from that in other mammals. We therefore sought to determine the genomic structure, including the FADS cluster in a 200-kbp range by sequencing gap regions. The structure we obtained was similar to that in other mammals. We then investigated the porcine FADS1 transcription start site and identified a novel isoform named FADS1b. Phylogenetic analysis revealed that the three members of the FADS cluster were orthologous among mammals, whereas the various FADS1 isoforms identified in pigs, mice and cattle might be attributable to species-specific transcriptional regulation with alternative promoters. Porcine FADS1b and FADS3 isoforms were predominantly expressed in the inner layer of the subcutaneous adipose tissue. Additional analyses will reveal the effects of these functionally unknown isoforms on fatty acid composition in pig fat tissues. Show less

Although many of the factors and molecules closely associated with non-alcoholic steatohepatitis (NASH) have been reported, the role of inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) on the progression of NASH remains unclear. We therefore investigated the role of iNOS-derived NO in NASH pathogenesis with a long-term follow-up study using systemic iNOS-knockout mice under high-fat diet (HFD) conditions. iNOS-knockout and wild-type mice were fed a basal or HFD for 10 or 48 weeks. Lipid accumulation, fibrosis, and inflammation were evaluated, and various factors and molecules closely associated with NASH were analyzed. Marked fibrosis and inflammation (indicators of NASH) were observed in the livers of iNOS-knockout mice compared to wild-type mice after 48 weeks of a HFD; however, lipid accumulation in iNOS-knockout mice livers was less than in the wild-type. Increased expressions of various cytokines that are transcriptionally controlled by NF-kB in iNOS-deficient mice livers were observed during HFD conditions. iNOS-derived NO may play a protective role against the progression to NASH during an HFD by preventing fibrosis and inflammation, which are mediated by NF-kB activation in Kupffer cells. A lack of iNOS-derived NO accelerates progression to NASH without excessive lipid accumulation. Show less