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1.
Cell ; 154(2): 430-41, 2013 Jul 18.
Article in English | MEDLINE | ID: mdl-23870130

ABSTRACT

NAD(+) is an important cofactor regulating metabolic homeostasis and a rate-limiting substrate for sirtuin deacylases. We show that NAD(+) levels are reduced in aged mice and Caenorhabditis elegans and that decreasing NAD(+) levels results in a further reduction in worm lifespan. Conversely, genetic or pharmacological restoration of NAD(+) prevents age-associated metabolic decline and promotes longevity in worms. These effects are dependent upon the protein deacetylase sir-2.1 and involve the induction of mitonuclear protein imbalance as well as activation of stress signaling via the mitochondrial unfolded protein response (UPR(mt)) and the nuclear translocation and activation of FOXO transcription factor DAF-16. Our data suggest that augmenting mitochondrial stress signaling through the modulation of NAD(+) levels may be a target to improve mitochondrial function and prevent or treat age-associated decline.


Subject(s)
Forkhead Transcription Factors/metabolism , Longevity , Mitochondria/metabolism , NAD/metabolism , Signal Transduction , Unfolded Protein Response , Aging , Animals , Caenorhabditis elegans/physiology , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Hepatocytes/metabolism , Mice , Poly(ADP-ribose) Polymerase Inhibitors , Reactive Oxygen Species/metabolism , Sirtuin 1/genetics , Sirtuin 1/metabolism , Sirtuins/genetics , Sirtuins/metabolism , Transcription Factors/metabolism
2.
Drug Resist Updat ; 73: 101054, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38277756

ABSTRACT

AIMS: Sirtuin 7 (SIRT7) plays an important role in tumor development, and has been characterized as a potent regulator of cellular stress. However, the effect of SIRT7 on sorafenib acquired resistance remains unclear and a possible anti-tumor mechanism beyond this process in HCC has not been clarified. We examined the therapeutic potential of SIRT7 and determined whether it functions synergistically with sorafenib to overcome chemoresistance. METHODS: Cancer Genome Atlas-liver HCC data and unbiased gene set enrichment analyses were used to identify SIRT7 as a potential effector molecule in sorafenib acquired resistance. Two types of SIRT7 chemical inhibitors were developed to evaluate its therapeutic properties when synergized with sorafenib. Mass spectrometry was performed to discover a direct target of SIRT7, DDX3X, and DDX3X deacetylation levels and protein stability were explored. Moreover, an in vivo xenograft model was used to confirm anti-tumor effect of SIRT7 and DDX3X chemical inhibitors combined with sorafenib. RESULTS: SIRT7 inhibition mediated DDX3X depletion can re-sensitize acquired sorafenib resistance by disrupting NLRP3 inflammasome assembly, finally suppressing hyperactive ERK1/2 signaling in response to NLRP3 inflammasome-mediated IL-1ß inhibition. CONCLUSIONS: SIRT7 is responsible for sorafenib acquired resistance, and its inhibition would be beneficial when combined with sorafenib by suppressing hyperactive pro-cell survival ERK1/2 signaling.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Sirtuins , Humans , Carcinoma, Hepatocellular/drug therapy , Carcinoma, Hepatocellular/genetics , Sorafenib/pharmacology , Sorafenib/therapeutic use , Liver Neoplasms/drug therapy , Liver Neoplasms/genetics , Inflammasomes/metabolism , Inflammasomes/pharmacology , Phosphorylation , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , MAP Kinase Signaling System , Drug Resistance, Neoplasm/genetics , Cell Line, Tumor , Cell Proliferation , DEAD-box RNA Helicases/genetics , DEAD-box RNA Helicases/metabolism , DEAD-box RNA Helicases/pharmacology , Sirtuins/genetics , Sirtuins/metabolism , Sirtuins/pharmacology
3.
Gastroenterology ; 164(3): 439-453, 2023 03.
Article in English | MEDLINE | ID: mdl-36402191

ABSTRACT

BACKGROUND & AIMS: Obesity predisposes to type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD), but underlying mechanisms are incompletely understood. Potassium channel tetramerization domain-containing protein 17 (Kctd17) levels are increased in livers from obese mice and humans. In this study, we investigated the mechanism of increased Kctd17 and whether it is causal to obesity-induced metabolic complications. METHODS: We transduced Rosa26-LSL-Cas9 knockin mice with AAV8-TBG-Cre (Control), AAV8-U6-Kctd17 sgRNA-TBG-Cre (L-Kctd17), AAV8-U6-Oga sgRNA-TBG-Cre (L-Oga), or AAV8-U6-Kctd17/Oga sgRNA-TBG-Cre (DKO). We fed mice a high-fat diet (HFD) and assessed for hepatic glucose and lipid homeostasis. We generated Kctd17, O-GlcNAcase (Oga), or Kctd17/Oga-knockout hepatoma cells by CRISPR-Cas9, and Kctd17-directed antisense oligonucleotide to test therapeutic potential in vivo. We analyzed transcriptomic data from patients with NAFLD. RESULTS: Hepatocyte Kctd17 expression was increased in HFD-fed mice due to increased Srebp1c activity. HFD-fed L-Kctd17 or Kctd17 antisense oligonucleotide-treated mice show improved glucose tolerance and hepatic steatosis, whereas forced Kctd17 expression caused glucose intolerance and hepatic steatosis even in lean mice. Kctd17 induced Oga degradation, resulting in increasing carbohydrate response element-binding protein (Chrebp) protein, so concomitant Oga knockout negated metabolic benefits of hepatocyte Kctd17 deletion. In patients with NAFLD, KCTD17 messenger RNA was positively correlated with expression of Chrebp target and other lipogenic genes. CONCLUSIONS: Srebp1c-induced hepatocyte Kctd17 expression in obesity disrupted glucose and lipid metabolism by stabilizing Chrebp, and may represent a novel therapeutic target for obesity-induced T2D and NAFLD.


Subject(s)
Diabetes Mellitus, Type 2 , Glucose Intolerance , Insulin Resistance , Non-alcoholic Fatty Liver Disease , Humans , Animals , Mice , Non-alcoholic Fatty Liver Disease/metabolism , Diabetes Mellitus, Type 2/complications , Insulin Resistance/physiology , Transcription Factors/genetics , Liver/metabolism , Hepatocytes/metabolism , Obesity/complications , Glucose/metabolism , Diet, High-Fat , Mice, Inbred C57BL , Adaptor Proteins, Signal Transducing/metabolism
4.
Eur J Clin Invest ; : e14290, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39044314

ABSTRACT

BACKGROUND: Growth differentiation factor 15 (GDF15), a stress-responsive cytokine from transforming growth factor superfamily, is highly expressed in mammalian tissues, including pancreas, stomach and intestine under pathological conditions. In particular, elevated levels of GDF15 might play an important role in the development and progression of various gastrointestinal cancers (GCs), suggesting its potential as a promising target for disease prediction and treatment. METHODS: In this review, systematic reviews addressing the role of GDF15 in GCs were updated, along with the latest clinical trials focussing on the GDF15-associated digestive malignancies. RESULTS: The multiple cellular pathways through which GDF15 is involved in the regulation of physiological and pathological conditions were first summarized. Then, GDF15 was also established as a valuable clinical index, functioning as a predictive marker in diverse GCs. Notably, latest clinical treatments targeting GDF15 were also highlighted, demonstrating its promising potential in mitigating and curing digestive malignancies. CONCLUSIONS: This review unveils the pivotal roles of GDF15 and its potential as a promising target in the pathogenesis of GCs, which may provide insightful directions for future investigations.

5.
Nature ; 563(7731): 354-359, 2018 11.
Article in English | MEDLINE | ID: mdl-30356218

ABSTRACT

Nicotinamide adenine dinucleotide (NAD+) is a co-substrate for several enzymes, including the sirtuin family of NAD+-dependent protein deacylases. Beneficial effects of increased NAD+ levels and sirtuin activation on mitochondrial homeostasis, organismal metabolism and lifespan have been established across species. Here we show that α-amino-ß-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD), the enzyme that limits spontaneous cyclization of α-amino-ß-carboxymuconate-ε-semialdehyde in the de novo NAD+ synthesis pathway, controls cellular NAD+ levels via an evolutionarily conserved mechanism in Caenorhabditis elegans and mouse. Genetic and pharmacological inhibition of ACMSD boosts de novo NAD+ synthesis and sirtuin 1 activity, ultimately enhancing mitochondrial function. We also characterize two potent and selective inhibitors of ACMSD. Because expression of ACMSD is largely restricted to kidney and liver, these inhibitors may have therapeutic potential for protection of these tissues from injury. In summary, we identify ACMSD as a key modulator of cellular NAD+ levels, sirtuin activity and mitochondrial homeostasis in kidney and liver.


Subject(s)
Carboxy-Lyases/metabolism , Conserved Sequence , Evolution, Molecular , Health , Mitochondria/physiology , NAD/biosynthesis , Animals , Caenorhabditis elegans/cytology , Caenorhabditis elegans/enzymology , Caenorhabditis elegans/metabolism , Carboxy-Lyases/antagonists & inhibitors , Carboxy-Lyases/chemistry , Carboxy-Lyases/deficiency , Cell Line , Choline , Disease Models, Animal , Female , Gene Knockdown Techniques , Hepatocytes/cytology , Hepatocytes/drug effects , Homeostasis/drug effects , Humans , Kidney/cytology , Kidney/drug effects , Liver/cytology , Liver/drug effects , Longevity/drug effects , Male , Methionine/deficiency , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/physiopathology , Non-alcoholic Fatty Liver Disease/prevention & control , Rats , Sirtuins/metabolism
6.
Cell Mol Life Sci ; 80(3): 69, 2023 Feb 23.
Article in English | MEDLINE | ID: mdl-36821008

ABSTRACT

Animal models have been utilized to understand the pathogenesis of Zellweger spectrum disorders (ZSDs); however, the link between clinical manifestations and molecular pathways has not yet been clearly established. We generated peroxin 5 homozygous mutant zebrafish (pex5-/-) to gain insight into the molecular pathogenesis of peroxisome dysfunction. pex5-/- display hallmarks of ZSD in humans and die within one month after birth. Fasting rapidly depletes lipids and glycogen in pex5-/- livers and expedites their mortality. Mechanistically, deregulated mitochondria and mechanistic target of rapamycin (mTOR) signaling act together to induce metabolic alterations that deplete hepatic nutrients and accumulate damaged mitochondria. Accordingly, chemical interventions blocking either the mitochondrial function or mTOR complex 1 (mTORC1) or a combination of both improve the metabolic imbalance shown in the fasted pex5-/- livers and extend the survival of animals. In addition, the suppression of oxidative stress by N-acetyl L-cysteine (NAC) treatment rescued the apoptotic cell death and early mortality observed in pex5-/-. Furthermore, an autophagy activator effectively ameliorated the early mortality of fasted pex5-/-. These results suggest that fasting may be detrimental to patients with peroxisome dysfunction, and that modulating the mitochondria, mTORC1, autophagy activities, or oxidative stress may provide a therapeutic option to alleviate the symptoms of peroxisomal diseases associated with metabolic dysfunction.


Subject(s)
Fasting , Mitochondria , Peroxisome-Targeting Signal 1 Receptor , Zebrafish , Animals , Humans , Autophagy/physiology , Mechanistic Target of Rapamycin Complex 1/metabolism , Mitochondria/metabolism , Peroxisomes/metabolism , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , Zebrafish/genetics , Zebrafish/metabolism , Peroxisome-Targeting Signal 1 Receptor/genetics , Peroxisome-Targeting Signal 1 Receptor/metabolism
7.
Genes Dev ; 30(11): 1255-60, 2016 06 01.
Article in English | MEDLINE | ID: mdl-27298334

ABSTRACT

Various tumors develop addiction to glutamine to support uncontrolled cell proliferation. Here we identify the nuclear receptor liver receptor homolog 1 (LRH-1) as a key regulator in the process of hepatic tumorigenesis through the coordination of a noncanonical glutamine pathway that is reliant on the mitochondrial and cytosolic transaminases glutamate pyruvate transaminase 2 (GPT2) and glutamate oxaloacetate transaminase 1 (GOT1), which fuel anabolic metabolism. In particular, we show that gain and loss of function of hepatic LRH-1 modulate the expression and activity of mitochondrial glutaminase 2 (GLS2), the first and rate-limiting step of this pathway. Acute and chronic deletion of hepatic LRH-1 blunts the deamination of glutamine and reduces glutamine-dependent anaplerosis. The robust reduction in glutaminolysis and the limiting availability of α-ketoglutarate in turn inhibit mTORC1 signaling to eventually block cell growth and proliferation. Collectively, these studies highlight the importance of LRH-1 in coordinating glutamine-induced metabolism and signaling to promote hepatocellular carcinogenesis.


Subject(s)
Carcinogenesis/metabolism , Carcinogenesis/pathology , Glutamine/metabolism , Liver Neoplasms/metabolism , Liver Neoplasms/physiopathology , Mitochondria/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Animals , Carcinogenesis/chemically induced , Diethylnitrosamine , Gene Expression Regulation, Neoplastic , Glutaminase/genetics , Glutaminase/metabolism , Liver/enzymology , Liver/metabolism , Liver/physiopathology , Liver Neoplasms/chemically induced , Liver Neoplasms/enzymology , Male , Mechanistic Target of Rapamycin Complex 1 , Mice , Mice, Knockout , Multiprotein Complexes/genetics , Multiprotein Complexes/metabolism , Receptors, Cytoplasmic and Nuclear/genetics , Signal Transduction , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism
8.
Int J Mol Sci ; 25(2)2024 Jan 09.
Article in English | MEDLINE | ID: mdl-38255882

ABSTRACT

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide. Targeted therapy against the epidermal growth factor receptor (EGFR) is a promising treatment approach for NSCLC. However, resistance to EGFR tyrosine kinase inhibitors (TKIs) remains a major challenge in its clinical management. EGFR mutation elevates the expression of hypoxia-inducible factor-1 alpha to upregulate the production of glycolytic enzymes, increasing glycolysis and tumor resistance. The inhibition of glycolysis can be a potential strategy for overcoming EGFR-TKI resistance and enhancing the effectiveness of EGFR-TKIs. In this review, we specifically explored the effectiveness of pyruvate dehydrogenase kinase inhibitors and lactate dehydrogenase A inhibitors in combating EGFR-TKI resistance. The aim was to summarize the effects of these natural products in preclinical NSCLC models to provide a comprehensive understanding of the potential therapeutic effects. The study findings suggest that natural products can be promising inhibitors of glycolytic enzymes for the treatment of EGFR-TKI-resistant NSCLC. Further investigations through preclinical and clinical studies are required to validate the efficacy of natural product-based glycolytic inhibitors as innovative therapeutic modalities for NSCLC.


Subject(s)
Biological Products , Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/drug therapy , Lung Neoplasms/drug therapy , Biological Products/pharmacology , Biological Products/therapeutic use , ErbB Receptors , Glycolysis
9.
J Cell Mol Med ; 27(9): 1157-1167, 2023 05.
Article in English | MEDLINE | ID: mdl-36992609

ABSTRACT

Growth and differentiation factor 15 (GDF15) is a member of the transforming growth factor-ß (TGF-ß) superfamily. GDF15 has been linked with several metabolic syndrome pathologies such as obesity and cardiovascular diseases. GDF15 is considered to be a metabolic regulator, although its precise mechanisms of action remain to be determined. Glial cell-derived neurotrophic factor family receptor alpha-like (GRAL), located in the hindbrain, has been identified as the receptor for GDF15 and signals through the coreceptor receptor tyrosine kinase (RET). Administration of GDF15 analogues in preclinical studies using various animal models has consistently been shown to induce weight loss through a reduction in food intake. GDF15, therefore, represents an attractive target to combat the current global obesity epidemic. In this article, we review current knowledge on GDF15 and its involvement in metabolic syndrome.


Subject(s)
Metabolic Syndrome , Animals , Growth Differentiation Factor 15/genetics , Glial Cell Line-Derived Neurotrophic Factor Receptors , Obesity/metabolism , Weight Loss
10.
Mol Psychiatry ; 27(4): 2030-2041, 2022 04.
Article in English | MEDLINE | ID: mdl-35165395

ABSTRACT

Cerebellar deficits with Purkinje cell (PCs) loss are observed in several neurologic disorders. However, the underlying mechanisms as to how the cerebellum is affected during development remain unclear. Here we demonstrated that specific inactivation of murine Ebp1 in the central nervous system causes a profound neuropathology characterized by reduced cerebellar volume and PCs loss with abnormal dendritic development, leading to phenotypes including motor defects and schizophrenia (SZ)-like behaviors. Loss of Ebp1 leads to untimely gene expression of Fbxw7, an E3 ubiquitin ligase, resulting in aberrant protein degradation of PTF1A, thereby eliciting cerebellar defects. Reinstatement of Ebp1, but not the Ebp1-E183Ter mutant found in SZ patients, reconstituted cerebellar architecture with increased PCs numbers and improved behavioral phenotypes. Thus, our findings indicate a crucial role for EBP1 in cerebellar development, and define a molecular basis for the cerebellar contribution to neurologic disorders such as SZ.


Subject(s)
Cerebellar Diseases , DNA-Binding Proteins/metabolism , RNA-Binding Proteins/metabolism , Schizophrenia , Animals , Cerebellar Diseases/metabolism , Cerebellum/pathology , Humans , Mice , Purkinje Cells/metabolism , RNA-Binding Proteins/genetics , Schizophrenia/metabolism
11.
EMBO Rep ; 22(5): e50766, 2021 05 05.
Article in English | MEDLINE | ID: mdl-33749979

ABSTRACT

SIRT7 is a NAD+ -dependent deacetylase that controls important aspects of metabolism, cancer, and bone formation. However, the molecular targets and functions of SIRT7 in the kidney are currently unknown. In silico analysis of kidney transcripts of the BXD murine genetic reference population revealed a positive correlation between Sirt7 and Slc12a7 mRNA expression, suggesting a link between the corresponding proteins that these transcripts encode, SIRT7, and the K-Cl cotransporter KCC4, respectively. Here, we find that protein levels and activity of heterologously expressed KCC4 are significantly modulated depending on its acetylation status in Xenopus laevis oocytes. Moreover, SIRT7 interacts with KCC4 in a NAD+ -dependent manner and increases its stability and activity in HEK293 cells. Interestingly, metabolic acidosis increases SIRT7 expression in kidney, as occurs with KCC4. In contrast, total SIRT7-deficient mice present lower KCC4 expression and an exacerbated metabolic acidosis than wild-type mice during an ammonium chloride challenge. Altogether, our data suggest that SIRT7 interacts with, stabilizes and modulates KCC4 activity through deacetylation, and reveals a novel role for SIRT7 in renal physiology.


Subject(s)
Sirtuins , Symporters , Acetylation , Animals , HEK293 Cells , Humans , Kidney , Mice , Sirtuins/genetics , Sirtuins/metabolism , Symporters/genetics , Symporters/metabolism , K Cl- Cotransporters
12.
Cell Mol Life Sci ; 79(2): 99, 2022 Jan 28.
Article in English | MEDLINE | ID: mdl-35089423

ABSTRACT

Angiotensin II (AngII) has potent cardiac hypertrophic effects mediated through activation of hypertrophic signaling like Wnt/ß-Catenin signaling. In the current study, we examined the role of protein arginine methyltransferase 7 (PRMT7) in cardiac function. PRMT7 was greatly decreased in hypertrophic hearts chronically infused with AngII and cardiomyocytes treated with AngII. PRMT7 depletion in rat cardiomyocytes resulted in hypertrophic responses. Consistently, mice lacking PRMT7 exhibited the cardiac hypertrophy and fibrosis. PRMT7 overexpression abrogated the cellular hypertrophy elicited by AngII, while PRMT7 depletion exacerbated the hypertrophic response caused by AngII. Similar with AngII treatment, the cardiac transcriptome analysis of PRMT7-deficient hearts revealed the alteration in gene expression profile related to Wnt signaling pathway. Inhibition of PRMT7 by gene deletion or an inhibitor treatment enhanced the activity of ß-catenin. PRMT7 deficiency decreases symmetric dimethylation of ß-catenin. Mechanistic studies reveal that methylation of arginine residue 93 in ß-catenin decreases the activity of ß-catenin. Taken together, our data suggest that PRMT7 is important for normal cardiac function through suppression of ß-catenin activity.


Subject(s)
Cardiomegaly/genetics , Myocardium/metabolism , Myocytes, Cardiac/metabolism , Protein-Arginine N-Methyltransferases/genetics , beta Catenin/genetics , Angiotensins , Animals , Cardiomegaly/chemically induced , Cardiomegaly/metabolism , Fibrosis , Gene Expression Profiling/methods , Humans , Male , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Myocardium/pathology , Protein-Arginine N-Methyltransferases/deficiency , RNA-Seq/methods , Wnt Signaling Pathway/genetics , beta Catenin/metabolism
13.
Small ; 18(1): e2106487, 2022 01.
Article in English | MEDLINE | ID: mdl-34854561

ABSTRACT

Cell-laden structures are widely applied for a variety of tissue engineering applications, including tissue restoration. Cell-to-cell interactions in bioprinted structures are important for successful tissue restoration, because cell-cell signaling pathways can regulate tissue development and stem cell fate. However, the low degree of cell-cell interaction in conventional cell-laden bioprinted structures is challenging for the therapeutic application of this modality. Herein, a microfluidic device with cell-laden methacrylated gelatin (GelMa) bioink and alginate as a matrix hydrogel is used to fabricate a functional hybrid structure laden with cell-aggregated microbeads. This approach effectively increases the degree of cell-to-cell interaction to a level comparable to cell spheroids. The hybrid structure is obtained using a one-step process without the exhausting procedure. It consists of cell bead fabrication and an extrusion process for the cell-bead laden structure. Different flow rates are appropriately selected to develop cell-laden struts with homogeneously distributed cell beads for each hydrogel in the process. The hybrid struts exhibit significantly higher cellular activities than those of conventional alginate/GelMa struts, which are bioprinted using similar cell densities and bioink formulations. Furthermore, hybrid struts with adipose stem cells are implanted into mice, resulting in significantly higher myogenesis in comparison to normally bioprinted struts.


Subject(s)
Hydrogels , Tissue Engineering , Alginates , Animals , Lab-On-A-Chip Devices , Mice , Printing, Three-Dimensional , Tissue Scaffolds
14.
Am J Nephrol ; 53(5): 407-415, 2022.
Article in English | MEDLINE | ID: mdl-35443245

ABSTRACT

INTRODUCTION: The patient-to-nurse ratio is highly variable among dialysis facilities. However, there is little known about the association between nurse caseload and hemodialysis (HD) patient outcomes. We evaluated the association between patient-to-nurse ratio and mortality in the Korean patients undergoing HD. METHODS: We used HD quality assessment data and National Health Insurance Service claim data from the year of 2013 for collecting demographic and clinical data. Altogether, 21,817 patients who participated in the HD quality assessment in 2013 were included in the study. Nurse caseload was defined as the number of HD sessions performed by a nurse per working day. The patients were divided into two groups according to the nurse caseload as follows: low nurse caseload group (≤6.0) and high nurse caseload group (>6.0). We analyzed mortality risk based on nurse caseload using the Cox proportional hazard model. RESULTS: The mean age was 59.1 years, and males accounted for 58.5%. The mean hemoglobin was 10.6 g/dL and albumin was 3.99 g/dL. At the mean follow-up duration of 51.7 (20.6) months, the ratio between low and high groups was 69.6% (15,184 patients) versus 30.4% (6,633 patients). The patients in the high nurse caseload group were older and showed lower levels of hemoglobin, albumin, calcium, and iron saturation and higher levels of phosphorus than those in the low nurse caseload group. A high nurse caseload was associated with a lower survival rate. In the adjusted Cox analysis, a high nurse caseload was an independent risk factor for all-cause mortality (hazard ratio 1.08; 95% confidence interval, 1.02-1.14; p = 0.01). CONCLUSION: High nurse caseload was associated with an increased mortality risk among the patients undergoing HD. Further prospective studies are needed to determine whether a caseload of nursing staff can improve the prognosis of HD patients.


Subject(s)
Kidney Failure, Chronic , Albumins , Cohort Studies , Hemoglobins , Humans , Kidney Failure, Chronic/therapy , Male , Middle Aged , Proportional Hazards Models , Renal Dialysis , Republic of Korea
15.
Proc Natl Acad Sci U S A ; 116(49): 24852-24860, 2019 12 03.
Article in English | MEDLINE | ID: mdl-31748268

ABSTRACT

ErbB3-binding protein 1 (EBP1) is implicated in diverse cellular functions, including apoptosis, cell proliferation, and differentiation. Here, by generating genetic inactivation of Ebp1 mice, we identified the physiological roles of EBP1 in vivo. Loss of Ebp1 in mice caused aberrant organogenesis, including brain malformation, and death between E13.5 and 15.5 owing to severe hemorrhages, with massive apoptosis and cessation of cell proliferation. Specific ablation of Ebp1 in neurons caused structural abnormalities of brain with neuron loss in [Nestin-Cre; Ebp1flox/flox ] mice. Notably, global methylation increased with high levels of the gene-silencing unit Suv39H1/DNMT1 in Ebp1-deficient mice. EBP1 repressed the transcription of Dnmt1 by binding to its promoter region and interrupted DNMT1-mediated methylation at its target gene, Survivin promoter region. Reinstatement of EBP1 into embryo brain relived gene repression and rescued neuron death. Our findings uncover an essential role for EBP1 in embryonic development and implicate its function in transcriptional regulation.


Subject(s)
DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Embryonic Development/genetics , Embryonic Development/physiology , Gene Silencing/physiology , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Animals , Apoptosis , Cell Cycle , Cell Proliferation , DNA (Cytosine-5-)-Methyltransferase 1/metabolism , Female , Gene Expression Regulation, Developmental , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Models, Animal , Transcription, Genetic
16.
Am J Med Genet A ; 185(12): 3866-3871, 2021 12.
Article in English | MEDLINE | ID: mdl-34325486

ABSTRACT

Beta-propeller protein-associated neurodegeneration (BPAN) is associated with mutations in the autophagy gene WDR45. The aim of this study was to demonstrate autophagic defects in a patient with BPAN. We assayed autophagic markers using western blot analysis and immunocytochemistry and applied transmission electron microscopy (TEM) to visualize the autophagic structures in fibroblasts from a 7-year-old Korean female with WDR45 splice-site mutation (c.977-1G>A; NM_007075.3). The protein and mRNA expression levels of WDR45 gene were decreased in the patient-derived fibroblasts. The amount of increase in LC3-II upon treatment with an autophagy inducer and inhibitor was reduced in mutant cells compared to control cells, suggesting decreased autophagic flux. TEM showed the accumulation of large vacuoles in mutant cells with a decrease of autophagosomes. Our study demonstrated that the WDR45 mutation in this patient impaired autophagy and provided additional insight into ultrastructural changes of autophagic structures.


Subject(s)
Brain/metabolism , Carrier Proteins/genetics , Genetic Predisposition to Disease , Neurodegenerative Diseases/genetics , Autophagy/genetics , Brain/ultrastructure , Carrier Proteins/ultrastructure , Child , Female , Fibroblasts/metabolism , Gene Expression Regulation/genetics , Humans , Microscopy, Electron, Transmission , Mutation/genetics , Neurodegenerative Diseases/pathology , Protein Isoforms/genetics
17.
Eur Heart J ; 41(9): 995-1005, 2020 03 01.
Article in English | MEDLINE | ID: mdl-31529020

ABSTRACT

AIMS: Nuclear receptors and their cofactors regulate key pathophysiological processes in atherosclerosis development. The transcriptional activity of these nuclear receptors is controlled by the nuclear receptor corepressors (NCOR), scaffolding proteins that form the basis of large corepressor complexes. Studies with primary macrophages demonstrated that the deletion of Ncor1 increases the expression of atherosclerotic molecules. However, the role of nuclear receptor corepressors in atherogenesis is unknown. METHODS AND RESULTS: We generated myeloid cell-specific Ncor1 knockout mice and crossbred them with low-density lipoprotein receptor (Ldlr) knockouts to study the role of macrophage NCOR1 in atherosclerosis. We demonstrate that myeloid cell-specific deletion of nuclear receptor corepressor 1 (NCOR1) aggravates atherosclerosis development in mice. Macrophage Ncor1-deficiency leads to increased foam cell formation, enhanced expression of pro-inflammatory cytokines, and atherosclerotic lesions characterized by larger necrotic cores and thinner fibrous caps. The immunometabolic effects of NCOR1 are mediated via suppression of peroxisome proliferator-activated receptor gamma (PPARγ) target genes in mouse and human macrophages, which lead to an enhanced expression of the CD36 scavenger receptor and subsequent increase in oxidized low-density lipoprotein uptake in the absence of NCOR1. Interestingly, in human atherosclerotic plaques, the expression of NCOR1 is reduced whereas the PPARγ signature is increased, and this signature is more pronounced in ruptured compared with non-ruptured carotid plaques. CONCLUSIONS: Our findings show that macrophage NCOR1 blocks the pro-atherogenic functions of PPARγ in atherosclerosis and suggest that stabilizing the NCOR1-PPARγ binding could be a promising strategy to block the pro-atherogenic functions of plaque macrophages and lesion progression in atherosclerotic patients.


Subject(s)
Atherosclerosis , Macrophages , Nuclear Receptor Co-Repressor 1 , PPAR gamma , Animals , Atherosclerosis/genetics , Atherosclerosis/prevention & control , Foam Cells , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Nuclear Receptor Co-Repressor 1/genetics , PPAR gamma/genetics , Receptors, LDL
18.
Int J Mol Sci ; 22(23)2021 Dec 05.
Article in English | MEDLINE | ID: mdl-34884947

ABSTRACT

Brown adipose tissue (BAT) is a major site for uncoupling protein 1 (UCP1)-mediated non-shivering thermogenesis. BAT dissipates energy via heat generation to maintain the optimal body temperature and increases energy expenditure. These energetic processes in BAT use large amounts of glucose and fatty acid. Therefore, the thermogenesis of BAT may be harnessed to treat obesity and related diseases. In mice and humans, BAT levels decrease with aging, and the underlying mechanism is elusive. Here, we compared the transcriptomic profiles of both young and aged BAT in response to thermogenic stimuli. The profiles were extracted from the GEO database. Intriguingly, aging does not cause transcriptional changes in thermogenic genes but upregulates several pathways related to the immune response and downregulates metabolic pathways. Acute severe CE upregulates several pathways related to protein folding. Chronic mild CE upregulates metabolic pathways, especially related to carbohydrate metabolism. Our findings provide a better understanding of the effects of aging and metabolic responses to thermogenic stimuli in BAT at the transcriptome level.


Subject(s)
Adipose Tissue, Brown/chemistry , Diet, High-Fat/adverse effects , Dioxoles/administration & dosage , Gene Expression Profiling/methods , Adipose Tissue, Brown/drug effects , Age Factors , Animals , Carbohydrate Metabolism , Cold Temperature , Dioxoles/adverse effects , Energy Metabolism , Gene Expression Regulation/drug effects , Humans , Mice , Models, Animal , Sequence Analysis, RNA , Thermogenesis/drug effects
19.
Int J Mol Sci ; 22(10)2021 May 20.
Article in English | MEDLINE | ID: mdl-34065602

ABSTRACT

Resistance to anticancer therapeutics occurs in virtually every type of cancer and becomes a major difficulty in cancer treatment. Although 5-fluorouracil (5FU) is the first-line choice of anticancer therapy for gastric cancer, its effectiveness is limited owing to drug resistance. Recently, altered cancer metabolism, including the Warburg effect, a preference for glycolysis rather than oxidative phosphorylation for energy production, has been accepted as a pivotal mechanism regulating resistance to chemotherapy. Thus, we investigated the detailed mechanism and possible usefulness of antiglycolytic agents in ameliorating 5FU resistance using established gastric cancer cell lines, SNU620 and SNU620/5FU. SNU620/5FU, a gastric cancer cell harboring resistance to 5FU, showed much higher lactate production and expression of glycolysis-related enzymes, such as lactate dehydrogenase A (LDHA), than those of the parent SNU620 cells. To limit glycolysis, we examined catechin and its derivatives, which are known anti-inflammatory and anticancer natural products because epigallocatechin gallate has been previously reported as a suppressor of LDHA expression. Catechin, the simplest compound among them, had the highest inhibitory effect on lactate production and LDHA activity. In addition, the combination of 5FU and catechin showed additional cytotoxicity and induced reactive oxygen species (ROS)-mediated apoptosis in SNU620/5FU cells. Thus, based on these results, we suggest catechin as a candidate for the development of a novel adjuvant drug that reduces chemoresistance to 5FU by restricting LDHA.


Subject(s)
Catechin/pharmacology , Drug Resistance, Neoplasm/drug effects , Fluorouracil/pharmacology , Lactate Dehydrogenase 5/metabolism , Stomach Neoplasms/drug therapy , Apoptosis/drug effects , Catechin/analogs & derivatives , Cell Line, Tumor , Glycolysis/drug effects , Humans , Reactive Oxygen Species/metabolism , Stomach/drug effects , Stomach Neoplasms/metabolism
20.
Molecules ; 26(6)2021 Mar 12.
Article in English | MEDLINE | ID: mdl-33809377

ABSTRACT

Muscle fatigue is induced by an acute or chronic physical performance inability after excessive physical activity often associated with lactate accumulation, the end-product of glycolysis. In this study, the water-extracted roots of Sanguisorba officinalis L., a herbal medicine traditionally used for inflammation and diarrhea, reduced the activities of lactate dehydrogenase A (LDHA) in in vitro enzyme assay myoblast C2C12 cells and murine muscle tissue. Physical performance measured by a treadmill test was improved in the S. officinalis-administrated group. The analysis of mouse serum and tissues showed significant changes in lactate levels. Among the proteins related to energy metabolism-related physical performance, phosphorylated-AMP-activated protein kinase alpha (AMPKα) and peroxisome proliferator-activated receptor-coactivator-1 alpha (PGC-1α) levels were enhanced, whereas the amount of LDHA was suppressed. Therefore, S. officinalis might be a candidate for improving physical performance via inhibiting LDHA and glycolysis.


Subject(s)
Lactate Dehydrogenase 5/antagonists & inhibitors , Physical Functional Performance , Plant Extracts/administration & dosage , Plants, Medicinal/chemistry , Sanguisorba/chemistry , AMP-Activated Protein Kinases/metabolism , Administration, Oral , Animals , Cell Line , Exercise Test , Glycolysis/drug effects , Lactic Acid/metabolism , Male , Medicine, Korean Traditional , Mice , Mice, Inbred C57BL , Myoblasts, Skeletal/drug effects , Myoblasts, Skeletal/enzymology , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Physical Endurance/drug effects , Phytochemicals/administration & dosage , Phytochemicals/chemistry , Phytotherapy , Plant Extracts/chemistry
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