1
|
McPhee M, Lee J, Salsman J, Pinelli M, Di Cara F, Rosen K, Dellaire G, Ridgway ND. Nuclear lipid droplets in Caco2 cells originate from nascent precursors and in situ at the nuclear envelope. J Lipid Res 2024; 65:100540. [PMID: 38570093 PMCID: PMC11077042 DOI: 10.1016/j.jlr.2024.100540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024] Open
Abstract
Intestinal epithelial cells convert excess fatty acids into triglyceride (TAG) for storage in cytoplasmic lipid droplets and secretion in chylomicrons. Nuclear lipid droplets (nLDs) are present in intestinal cells but their origin and relationship to cytoplasmic TAG synthesis and secretion is unknown. nLDs and related lipid-associated promyelocytic leukemia structures (LAPS) were abundant in oleate-treated Caco2 but less frequent in other human colorectal cancer cell lines and mouse intestinal organoids. nLDs and LAPS in undifferentiated oleate-treated Caco2 cells harbored the phosphatidate phosphatase Lipin1, its product diacylglycerol, and CTP:phosphocholine cytidylyltransferase (CCT)α. CCTα knockout Caco2 cells had fewer but larger nLDs, indicating a reliance on de novo PC synthesis for assembly. Differentiation of Caco2 cells caused large nLDs and LAPS to form regardless of oleate treatment or CCTα expression. nLDs and LAPS in Caco2 cells did not associate with apoCIII and apoAI and formed dependently of microsomal triglyceride transfer protein expression and activity, indicating they are not derived from endoplasmic reticulum luminal LDs precursors. Instead, undifferentiated Caco2 cells harbored a constitutive pool of nLDs and LAPS in proximity to the nuclear envelope that expanded in size and number with oleate treatment. Inhibition of TAG synthesis did affect the number of nascent nLDs and LAPS but prevented their association with promyelocytic leukemia protein, Lipin1α, and diacylglycerol, which instead accumulated on the nuclear membranes. Thus, nLD and LAPS biogenesis in Caco2 cells is not linked to lipoprotein secretion but involves biogenesis and/or expansion of nascent nLDs by de novo lipid synthesis.
Collapse
Affiliation(s)
- Michael McPhee
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jonghwa Lee
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jayme Salsman
- Depts of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Marinella Pinelli
- Dept of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Francesca Di Cara
- Dept of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kirill Rosen
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Graham Dellaire
- Depts of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Neale D Ridgway
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada.
| |
Collapse
|
2
|
Riaz TA, Junjappa RP, Handigund M, Ferdous J, Kim HR, Chae HJ. Role of Endoplasmic Reticulum Stress Sensor IRE1α in Cellular Physiology, Calcium, ROS Signaling, and Metaflammation. Cells 2020; 9:E1160. [PMID: 32397116 PMCID: PMC7290600 DOI: 10.3390/cells9051160] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 04/27/2020] [Accepted: 05/06/2020] [Indexed: 12/14/2022] Open
Abstract
Inositol-requiring transmembrane kinase endoribonuclease-1α (IRE1α) is the most prominent and evolutionarily conserved unfolded protein response (UPR) signal transducer during endoplasmic reticulum functional upset (ER stress). A IRE1α signal pathway arbitrates yin and yang of cellular fate in objectionable conditions. It plays several roles in fundamental cellular physiology as well as in several pathological conditions such as diabetes, obesity, inflammation, cancer, neurodegeneration, and in many other diseases. Thus, further understanding of its molecular structure and mechanism of action during different cell insults helps in designing and developing better therapeutic strategies for the above-mentioned chronic diseases. In this review, recent insights into structure and mechanism of activation of IRE1α along with its complex regulating network were discussed in relation to their basic cellular physiological function. Addressing different binding partners that can modulate IRE1α function, UPRosome triggers different downstream pathways depending on the cellular backdrop. Furthermore, IRE1α are in normal cell activities outside the dominion of ER stress and activities under the weather of inflammation, diabetes, and obesity-related metaflammation. Thus, IRE1 as an ER stress sensor needs to be understood from a wider perspective for comprehensive functional meaning, which facilitates us with assembling future needs and therapeutic benefits.
Collapse
Affiliation(s)
- Thoufiqul Alam Riaz
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Jeonbuk National University, Jeonju 54907, Korea; (T.A.R.); (R.P.J.)
| | - Raghu Patil Junjappa
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Jeonbuk National University, Jeonju 54907, Korea; (T.A.R.); (R.P.J.)
| | - Mallikarjun Handigund
- Department of Laboratory Medicine, Jeonbuk National University, Medical School, Jeonju 54907, Korea;
| | - Jannatul Ferdous
- Department of Radiology and Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Korea;
| | - Hyung-Ryong Kim
- College of Dentistry, Dankook University, Cheonan 31116, Korea
| | - Han-Jung Chae
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Jeonbuk National University, Jeonju 54907, Korea; (T.A.R.); (R.P.J.)
| |
Collapse
|
3
|
Iqbal J, Jahangir Z, Al-Qarni AA. Microsomal Triglyceride Transfer Protein: From Lipid Metabolism to Metabolic Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:37-52. [DOI: 10.1007/978-981-15-6082-8_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
4
|
Dai F, Dong S, Rong Z, Xuan Q, Chen P, Chen M, Fan Y, Gao Q. Expression of inositol-requiring enzyme 1β is downregulated in azoxymethane/dextran sulfate sodium-induced mouse colonic tumors. Exp Ther Med 2019; 17:3181-3188. [PMID: 30936991 DOI: 10.3892/etm.2019.7317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/22/2018] [Indexed: 12/28/2022] Open
Abstract
Inflammatory bowel disease (IBD) is a risk factor in colon cancer. Endoplasmic reticulum (ER) stress is associated with IBD and cancer. In the current study an azoxymethane (AOM) and dextran sulfate sodium (DSS)-induced mouse colonic tumor model was established to analyze the expression of ER stress chaperone molecules. Female C57BL/6 mice were intraperitoneally injected with 12 mg/kg AOM. On the 7th day following AOM injection, mice were treated with 1% DSS supplemented to the drinking water for 7 days, then followed by 14 days of normal drinking water. The cycle of 7 days DSS plus 14 days normal water was repeated twice and colonic tumors were evaluated for their number and size. Mice in the control group were injected with saline and received normal drinking water for the course of the experiment. mRNA levels of cytokines, inositol-requiring enzyme (IRE)1α and 1β, their downstream targets X-box binding protein (XBP)1u, XBP1s and mucin (MUC) 2 and interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-α were detected by reverse transcription-quantitative polymerase chain reaction. IRE1α, IRE1β and MUC2 protein expression was evaluated by immunohistochemistry, and IRE1α and IRE1β levels were further assessed by western blot analysis. It was observed that tumors developed in the distal colon of mice treated with AOM/DSS. IL-6, IL-8 and TNF-α mRNA levels were significantly increased in mice of the tumor group compared with mice of the control group. There were no significant differences in IRE1α mRNA and protein expression between the two groups and XBP1s mRNA levels were increased in the tumor compared with the control group. IRE1β and MUC2 mRNA levels were significantly decreased in the tumor compared with the control group (decreased by 42 and 30%, respectively). IRE1β and MUC2 proteins were predominately expressed in colonic epithelial cells and expression was decreased in the tumor compared with the control group. In conclusion, the downregulation of IRE1β and MUC2 may reduce the ability of colon tissues to resist inflammation, thus promoting the occurrence and development of colonic tumors.
Collapse
Affiliation(s)
- Faliang Dai
- Department of Gastroenterology and Hepatology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing 100144, P.R. China.,Department of Gastroenterology and Hepatology, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China.,Department of Surgery, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China.,Department of Minimally Invasive Interventional Oncology, Caoxian People's Hospital, Heze, Shandong 274400, P.R. China
| | - Shizhen Dong
- Department of Clinical Laboratory Diagnosis, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Zhenhua Rong
- Department of Minimally Invasive Interventional Oncology, Caoxian People's Hospital, Heze, Shandong 274400, P.R. China
| | - Qingxia Xuan
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China.,Department of Ultrasound, Women and Children Health Care Center of Luoyang, Luoyang, Henan 471000, P.R. China
| | - Pan Chen
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Menglu Chen
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Yonggang Fan
- Department of Surgery, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Qiang Gao
- Department of Gastroenterology and Hepatology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing 100144, P.R. China.,Department of Gastroenterology and Hepatology, The First Affiliated Hospital and Clinical Medical College, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| |
Collapse
|
5
|
Pena RN, Noguera JL, García-Santana MJ, González E, Tejeda JF, Ros-Freixedes R, Ibáñez-Escriche N. Five genomic regions have a major impact on fat composition in Iberian pigs. Sci Rep 2019; 9:2031. [PMID: 30765794 PMCID: PMC6375979 DOI: 10.1038/s41598-019-38622-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 12/18/2018] [Indexed: 12/22/2022] Open
Abstract
The adipogenic nature of the Iberian pig defines many quality attributes of its fresh meat and dry-cured products. The distinct varieties of Iberian pig exhibit great variability in the genetic parameters for fat deposition and composition in muscle. The aim of this work is to identify common and distinct genomic regions related to fatty acid composition in Retinto, Torbiscal, and Entrepelado Iberian varieties and their reciprocal crosses through a diallelic experiment. In this study, we performed GWAS using a high density SNP array on 382 pigs with the multimarker regression Bayes B method implemented in GenSel. A number of genomic regions showed strong associations with the percentage of saturated and unsaturated fatty acid in intramuscular fat. In particular, five regions with Bayes Factor >100 (SSC2 and SSC7) or >50 (SSC2 and SSC12) explained an important fraction of the genetic variance for miristic, palmitoleic, monounsaturated (>14%), oleic (>10%) and polyunsaturated (>5%) fatty acids. Six genes (RXRB, PSMB8, CHGA, ACACA, PLIN4, PLIN5) located in these regions have been investigated in relation to intramuscular composition variability in Iberian pigs, with two SNPs at the RXRB gene giving the most consistent results on oleic and monounsaturated fatty acid content.
Collapse
Affiliation(s)
- R N Pena
- Departament de Ciència Animal, Universitat de Lleida-Agrotecnio Center, 25198, Lleida, Spain
| | - J L Noguera
- IRTA, Genètica i Millora Animal, 25198, Lleida, Spain
| | | | - E González
- Tecnología de los alimentos, Universidad de Extremadura, 06006, Badajoz, Spain
| | - J F Tejeda
- Tecnología de los alimentos, Universidad de Extremadura, 06006, Badajoz, Spain
| | - R Ros-Freixedes
- Departament de Ciència Animal, Universitat de Lleida-Agrotecnio Center, 25198, Lleida, Spain.,The Roslin Institute, Edinburgh University, Easter Bush, EH25 9RG, UK
| | - N Ibáñez-Escriche
- Institute for Animal Science and Technology, Universitat Politècnica de València, 46022, Valencia, Spain.
| |
Collapse
|
6
|
Meng Z, Gwag T, Sui Y, Park SH, Zhou X, Zhou C. The atypical antipsychotic quetiapine induces hyperlipidemia by activating intestinal PXR signaling. JCI Insight 2019; 4:125657. [PMID: 30728326 DOI: 10.1172/jci.insight.125657] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/03/2019] [Indexed: 12/11/2022] Open
Abstract
Quetiapine, one of the most prescribed atypical antipsychotics, has been associated with hyperlipidemia and an increased risk for cardiovascular disease in patients, but the underlying mechanisms remain unknown. Here, we identified quetiapine as a potent and selective agonist for pregnane X receptor (PXR), a key nuclear receptor that regulates xenobiotic metabolism in the liver and intestine. Recent studies have indicated that PXR also plays an important role in lipid homeostasis. We generated potentially novel tissue-specific PXR-KO mice and demonstrated that quetiapine induced hyperlipidemia by activating intestinal PXR signaling. Quetiapine-mediated PXR activation stimulated the intestinal expression of cholesterol transporter Niemann-Pick C1-Like 1 (NPC1L1) and microsomal triglyceride transfer protein (MTP), leading to increased intestinal lipid absorption. While NPC1L1 is a known PXR target gene, we identified a DR-1-type PXR-response element in the MTP promoter and established MTP as a potentially novel transcriptional target of PXR. Quetiapine's effects on PXR-mediated gene expression and cholesterol uptake were also confirmed in cultured murine enteroids and human intestinal cells. Our findings suggest a potential role of PXR in mediating adverse effects of quetiapine in humans and provide mechanistic insights for certain atypical antipsychotic-associated dyslipidemia.
Collapse
Affiliation(s)
- Zhaojie Meng
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Taesik Gwag
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Yipeng Sui
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Se-Hyung Park
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Xiangping Zhou
- Department of Neurology, SUNY Upstate Medical College, Syracuse, New York, USA
| | - Changcheng Zhou
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| |
Collapse
|
7
|
Klepsch V, Gerner RR, Klepsch S, Olson WJ, Tilg H, Moschen AR, Baier G, Hermann-Kleiter N. Nuclear orphan receptor NR2F6 as a safeguard against experimental murine colitis. Gut 2018; 67:1434-1444. [PMID: 28779026 PMCID: PMC6204953 DOI: 10.1136/gutjnl-2016-313466] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 04/26/2017] [Accepted: 05/19/2017] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Nuclear receptors are known to regulate both immune and barrier functions in the GI tract. The nuclear orphan receptor NR2F6 has been shown to suppress the expression of proinflammatory cytokines in T lymphocytes. NR2F6 gene expression is reduced in patients with IBS or UC, but its functional role and tissue dependency in healthy and inflamed gut have not yet been investigated. DESIGN Intestinal inflammation was induced in wild-type, Nr2f6-deficient, Rag1-deficient or bone marrow-reconstituted mice by administration of chemical (dextran sodium sulfate (DSS)) and immunogenic (T cell transfer) triggers. Disease phenotypes were investigated by survival, body weight, colon length and analysis of immune cell infiltrates. Additionally, histology, intestinal permeability, tight junction proteins, bacterial fluorescence in situ hybridisation, apoptosis, cell proliferation and mucus production were investigated. RESULTS Nr2f6-deficient mice were highly susceptible to DSS-induced colitis characterised by enhanced weight loss, increased colonic tissue destruction and immune cell infiltration together with enhanced intestinal permeability and reduced Muc2 expression. T cell transfer colitis and bone marrow reconstitution experiments demonstrated that disease susceptibility was not dependent on the expression of Nr2f6 in the immune compartment but on the protective role of NR2F6 in the intestinal epithelium. Mechanistically, we show that NR2F6 binds to a consensus sequence at -2 kb of the Muc2 promoter and transactivates Muc2 expression. Loss of NR2F6 alters intestinal permeability and results in spontaneous late-onset colitis in Nr2f6-deficient mice. CONCLUSION We have for the first time identified a fundamental and non-redundant role of NR2F6 in protecting gut barrier homeostasis.
Collapse
Affiliation(s)
- Victoria Klepsch
- Translational Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Innsbruck, Tirol, Austria
| | - Romana R Gerner
- Department of Internal Medicine I, Gastroenterology, Endocrinology & Metabolism, Medical University Innsbruck, Innsbruck, Tirol, Austria
| | - Sebastian Klepsch
- Translational Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Innsbruck, Tirol, Austria
| | - William J Olson
- Translational Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Innsbruck, Tirol, Austria
| | - Herbert Tilg
- Department of Internal Medicine I, Gastroenterology, Endocrinology & Metabolism, Medical University Innsbruck, Innsbruck, Tirol, Austria
| | - Alexander R Moschen
- Department of Internal Medicine I, Gastroenterology, Endocrinology & Metabolism, Medical University Innsbruck, Innsbruck, Tirol, Austria
| | - Gottfried Baier
- Translational Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Innsbruck, Tirol, Austria
| | - Natascha Hermann-Kleiter
- Translational Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Innsbruck, Tirol, Austria
| |
Collapse
|
8
|
Jiang Y, Zhou Y, Zheng Y, Guo H, Gao L, Chen P, Feng D, Qi R, Li X, Chang Y, Chu FF, Gao Q. Expression of inositol-requiring enzyme 1β is downregulated in colorectal cancer. Oncol Lett 2017; 13:1109-1118. [PMID: 28454221 PMCID: PMC5403352 DOI: 10.3892/ol.2017.5590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/12/2016] [Indexed: 12/22/2022] Open
Abstract
The endoplasmic reticulum stress inositol-requiring enzyme (IRE) 1α/X-box binding protein (XBP) 1 signaling pathway is involved in the tumorigenesis of breast and prostate cancer. Mucin 2 (MUC2) protects colon tissues from the formation of tumors. In human colorectal cancer (CRC) the role of IRE1α, and its analogue, IRE1β, has yet to be elucidated. In the present study, the expression levels of IRE1α, IRE1β, un-spliced XBP1u, spliced XBP1s and MUC2 in surgically resected cancerous and adjacent non-cancerous tissues from patients with CRC were investigated. The IRE1α, IRE1β, XBP1u, XBP1s and MUC2 mRNA expression levels were determined using reverse transcription-quantitative polymerase chain reaction, and the protein expression levels were detected using immunohistochemistry and western blotting. The association between the expression levels of IRE1α, IRE1β and MUC2 and the clinicopathological features of patients with CRC was subsequently analyzed. The mRNA expression levels of IRE1β and MUC2 were decreased by ~2.1 and ~4.5-fold in CRC tissues, respectively, as compared with the adjacent normal tissues. The protein expression levels of IRE1β and MUC2 were decreased by ~8.0 and ~2.0-fold in the CRC tissues, respectively. IRE1β mRNA expression levels were positively correlated with MUC2 mRNA expression levels. IRE1β expression levels were revealed to be significantly associated with lymph node metastasis, tumor stage and histological differentiation. However, IRE1α, XBP1u and XBP1s mRNA and IRE1α protein expression levels were not observed to significantly differ between cancerous tissues and the adjacent normal tissues. The results indicated that the expression of IRE1β, but not IRE1α, may protect colon tissue from developing CRC by inducing MUC2 expression. Therefore, decreased IRE1β expression levels may be associated with the development of CRC through the inhibition of MUC2 expression.
Collapse
Affiliation(s)
- Yalin Jiang
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China.,Department of Clinical Laboratory, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Yunfeng Zhou
- Shenzhen University Health Science Center, Shenzhen, Guangdong 518060, P.R. China
| | - Yufeng Zheng
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Hong Guo
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Lei Gao
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Pan Chen
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Dandan Feng
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Ran Qi
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Xiaozhen Li
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Yongchao Chang
- Department of Clinical Laboratory, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Fong-Fong Chu
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Qiang Gao
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| |
Collapse
|
9
|
Bao MH, Luo HQ, Chen LH, Tang L, Ma KF, Xiang J, Dong LP, Zeng J, Li GY, Li JM. Impact of high fat diet on long non-coding RNAs and messenger RNAs expression in the aortas of ApoE(-/-) mice. Sci Rep 2016; 6:34161. [PMID: 27698357 PMCID: PMC5048419 DOI: 10.1038/srep34161] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/07/2016] [Indexed: 12/13/2022] Open
Abstract
Atherosclerosis is a chronic multifactorial inflammatory disease with high prevalence worldwide, and has become the leading cause of death. The present study was designed to investigate the impact of high-fat diet on ApoE(−/−) mice exhibiting atherosclerosis by detecting the genome-wide expression profile of lncRNAs and mRNAs. A total of 354 differentially expressed lncRNAs were identified (≥2.0 folds). Simultaneously, 357 differentially expressed mRNAs from the same chip were found. The expression differences of lncRNAs and mRNAs were consistent in both qPCR and microarray detection. Annotation results of the mRNAs which correlated with lncRNAs showed that the commonly related pathways were metabolism and inflammation. Hypergeometric distribution analysis indicated that the differentially expressed lncRNAs had been mostly regulated by transcription factors (TFs) such as Myod1, Rxra, Pparg, Tcf3, etc. Additional lncRNA-target-TFs network analysis was conducted for the top 20 differentially expressed lncRNAs. The results indicated Hnf4a, Ppara, Vdr, and Runx3 as the TFs most likely to regulate the production of these lncRNAs, and might play roles in inflammatory and metabolic processes in atherosclerosis. In a nutshell, the present study identified a panel of dysregulated lncRNAs and mRNAs that may be potential biomarkers or drug targets relevant to the high-fat diet related atherogenesis.
Collapse
Affiliation(s)
- Mei-Hua Bao
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Huai-Qing Luo
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Li-Hua Chen
- The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Liang Tang
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Kui-Fen Ma
- The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Ju Xiang
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Li-Ping Dong
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Jie Zeng
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Guang-Yi Li
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China
| | - Jian-Ming Li
- Department of Anatomy, Histology and Embryology, Institute of of Neuroscience, Changsha Medical University, Changsha, 410219, China.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.,Department of Anatomy, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China
| |
Collapse
|
10
|
Costabile BK, Kim YK, Iqbal J, Zuccaro MV, Wassef L, Narayanasamy S, Curley RW, Harrison EH, Hussain MM, Quadro L. β-Apo-10'-carotenoids Modulate Placental Microsomal Triglyceride Transfer Protein Expression and Function to Optimize Transport of Intact β-Carotene to the Embryo. J Biol Chem 2016; 291:18525-35. [PMID: 27402843 DOI: 10.1074/jbc.m116.738336] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Indexed: 11/06/2022] Open
Abstract
β-Carotene is an important source of vitamin A for the mammalian embryo, which depends on its adequate supply to achieve proper organogenesis. In mammalian tissues, β-carotene 15,15'-oxygenase (BCO1) converts β-carotene to retinaldehyde, which is then oxidized to retinoic acid, the biologically active form of vitamin A that acts as a transcription factor ligand to regulate gene expression. β-Carotene can also be cleaved by β-carotene 9',10'-oxygenase (BCO2) to form β-apo-10'-carotenal, a precursor of retinoic acid and a transcriptional regulator per se The mammalian embryo obtains β-carotene from the maternal circulation. However, the molecular mechanisms that enable its transfer across the maternal-fetal barrier are not understood. Given that β-carotene is transported in the adult bloodstream by lipoproteins and that the placenta acquires, assembles, and secretes lipoproteins, we hypothesized that the aforementioned process requires placental lipoprotein biosynthesis. Here we show that β-carotene availability regulates transcription and activity of placental microsomal triglyceride transfer protein as well as expression of placental apolipoprotein B, two key players in lipoprotein biosynthesis. We also show that β-apo-10'-carotenal mediates the transcriptional regulation of microsomal triglyceride transfer protein via hepatic nuclear factor 4α and chicken ovalbumin upstream promoter transcription factor I/II. Our data provide the first in vivo evidence of the transcriptional regulatory activity of β-apocarotenoids and identify microsomal triglyceride transfer protein and its transcription factors as the targets of their action. This study demonstrates that β-carotene induces a feed-forward mechanism in the placenta to enhance the assimilation of β-carotene for proper embryogenesis.
Collapse
Affiliation(s)
- Brianna K Costabile
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Youn-Kyung Kim
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Jahangir Iqbal
- Departments of Cell Biology and Pediatrics, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York 11203, and
| | - Michael V Zuccaro
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Lesley Wassef
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Sureshbabu Narayanasamy
- College of Pharmacy and Department of Human Nutrition, The Ohio State University, Columbus, Ohio 43210
| | | | - Earl H Harrison
- Department of Human Nutrition, The Ohio State University, Columbus, Ohio 43210
| | - M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York 11203, and
| | - Loredana Quadro
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901,
| |
Collapse
|
11
|
Levy E. Insights from human congenital disorders of intestinal lipid metabolism. J Lipid Res 2014; 56:945-62. [PMID: 25387865 DOI: 10.1194/jlr.r052415] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Indexed: 12/24/2022] Open
Abstract
The intestine must challenge the profuse daily flux of dietary fat that serves as a vital source of energy and as an essential component of cell membranes. The fat absorption process takes place in a series of orderly and interrelated steps, including the uptake and translocation of lipolytic products from the brush border membrane to the endoplasmic reticulum, lipid esterification, Apo synthesis, and ultimately the packaging of lipid and Apo components into chylomicrons (CMs). Deciphering inherited disorders of intracellular CM elaboration afforded new insight into the key functions of crucial intracellular proteins, such as Apo B, microsomal TG transfer protein, and Sar1b GTPase, the defects of which lead to hypobetalipoproteinemia, abetalipoproteinemia, and CM retention disease, respectively. These "experiments of nature" are characterized by fat malabsorption, steatorrhea, failure to thrive, low plasma levels of TGs and cholesterol, and deficiency of liposoluble vitamins and essential FAs. After summarizing and discussing the functions and regulation of these proteins for reader's comprehension, the current review focuses on their specific roles in malabsorptions and dyslipidemia-related intestinal fat hyperabsorption while dissecting the spectrum of clinical manifestations and managements. The influence of newly discovered proteins (proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 protein) on fat absorption has also been provided. Finally, it is stressed how the overexpression or polymorphism status of the critical intracellular proteins promotes dyslipidemia and cardiometabolic disorders.
Collapse
Affiliation(s)
- Emile Levy
- Research Centre, CHU Sainte-Justine and Department of Nutrition, Université de Montréal, Montreal, Quebec H3T 1C5, Canada
| |
Collapse
|
12
|
Maurel M, Chevet E, Tavernier J, Gerlo S. Getting RIDD of RNA: IRE1 in cell fate regulation. Trends Biochem Sci 2014; 39:245-54. [PMID: 24657016 DOI: 10.1016/j.tibs.2014.02.008] [Citation(s) in RCA: 428] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
Inositol-requiring enzyme 1 (IRE1) is the most conserved transducer of the unfolded protein response (UPR), a homeostatic response that preserves proteostasis. Intriguingly, via its endoribonuclease activity, IRE1 produces either adaptive or death signals. This occurs through both unconventional splicing of XBP1 mRNA and regulated IRE1-dependent decay of mRNA (RIDD). Whereas XBP1 mRNA splicing is cytoprotective in response to endoplasmic reticulum (ER) stress, RIDD has revealed many unexpected features. For instance, RIDD cleaves RNA at an XBP1-like consensus site but with an activity divergent from XBP1 mRNA splicing and can either preserve ER homeostasis or induce cell death. Here we review recent findings on RIDD and propose a model of how IRE1 RNase activity might control cell fate decisions.
Collapse
Affiliation(s)
- M Maurel
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| | - E Chevet
- INSERM U1053, Université Bordeaux Segalen, 33000 Bordeaux, France; Centre Régional de Lutte Contre le Cancer Eugène Marquis, 35000 Rennes, France
| | - J Tavernier
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - S Gerlo
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| |
Collapse
|
13
|
Chiang DY, Cuthbertson DW, Ruiz FR, Li N, Pereira FA. A coregulatory network of NR2F1 and microRNA-140. PLoS One 2013; 8:e83358. [PMID: 24349493 PMCID: PMC3857795 DOI: 10.1371/journal.pone.0083358] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 11/11/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Both nuclear receptor subfamily 2 group F member 1 (NR2F1) and microRNAs (miRNAs) have been shown to play critical roles in the developing and functional inner ear. Based on previous studies suggesting interplay between NR2F1 and miRNAs, we investigated the coregulation between NR2F1 and miRNAs to better understand the regulatory mechanisms of inner ear development and functional maturation. RESULTS Using a bioinformatic approach, we identified 11 potential miRNAs that might coregulate target genes with NR2F1 and analyzed their targets and potential roles in physiology and disease. We selected 6 miRNAs to analyze using quantitative real-time (qRT) -PCR and found that miR-140 is significantly down-regulated by 4.5-fold (P=0.004) in the inner ear of NR2F1 knockout (Nr2f1(-/-)) mice compared to wild-type littermates but is unchanged in the brain. Based on this, we performed chromatin-immunoprecipitation followed by qRT-PCR and confirmed that NR2F1 directly binds and regulates both miR-140 and Klf9 in vivo. Furthermore, we performed luciferase reporter assay and showed that miR-140 mimic directly regulates KLF9-3'UTR, thereby establishing and validating an example coregulatory network involving NR2F1, miR-140, and Klf9. CONCLUSIONS We have described and experimentally validated a novel tissue-dependent coregulatory network for NR2F1, miR-140, and Klf9 in the inner ear and we propose the existence of many such coregulatory networks important for both inner ear development and function.
Collapse
Affiliation(s)
- David Y. Chiang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - David W. Cuthbertson
- Bobby R. Alford Department of Otolaryngology- Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, United States of America
| | - Fernanda R. Ruiz
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Na Li
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Fred A. Pereira
- Bobby R. Alford Department of Otolaryngology- Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, United States of America
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| |
Collapse
|
14
|
Iskander KN, Osuchowski MF, Stearns-Kurosawa DJ, Kurosawa S, Stepien D, Valentine C, Remick DG. Sepsis: multiple abnormalities, heterogeneous responses, and evolving understanding. Physiol Rev 2013; 93:1247-88. [PMID: 23899564 DOI: 10.1152/physrev.00037.2012] [Citation(s) in RCA: 284] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sepsis represents the host's systemic inflammatory response to a severe infection. It causes substantial human morbidity resulting in hundreds of thousands of deaths each year. Despite decades of intense research, the basic mechanisms still remain elusive. In either experimental animal models of sepsis or human patients, there are substantial physiological changes, many of which may result in subsequent organ injury. Variations in age, gender, and medical comorbidities including diabetes and renal failure create additional complexity that influence the outcomes in septic patients. Specific system-based alterations, such as the coagulopathy observed in sepsis, offer both potential insight and possible therapeutic targets. Intracellular stress induces changes in the endoplasmic reticulum yielding misfolded proteins that contribute to the underlying pathophysiological changes. With these multiple changes it is difficult to precisely classify an individual's response in sepsis as proinflammatory or immunosuppressed. This heterogeneity also may explain why most therapeutic interventions have not improved survival. Given the complexity of sepsis, biomarkers and mathematical models offer potential guidance once they have been carefully validated. This review discusses each of these important factors to provide a framework for understanding the complex and current challenges of managing the septic patient. Clinical trial failures and the therapeutic interventions that have proven successful are also discussed.
Collapse
Affiliation(s)
- Kendra N Iskander
- Department of Pathology, Boston University School of Medicine, Boston, Massachusetts, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Soh J, Iqbal J, Queiroz J, Fernandez-Hernando C, Hussain MM. MicroRNA-30c reduces hyperlipidemia and atherosclerosis in mice by decreasing lipid synthesis and lipoprotein secretion. Nat Med 2013; 19:892-900. [PMID: 23749231 PMCID: PMC4121125 DOI: 10.1038/nm.3200] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 04/16/2013] [Indexed: 02/07/2023]
Abstract
Hyperlipidemia is a risk factor for various cardiovascular and metabolic disorders. Overproduction of lipoproteins, a process critically dependent on microsomal triglyceride transfer protein (MTP), can contribute to hyperlipidemia. We show that microRNA-30c (miR-30c) interacts with the 3′-untranslated region of the MTP mRNA and induces degradation leading to reductions in its activity and media apolipoprotein B. Further, miR-30c reduces hyperlipidemia and atherosclerosis in Western diet fed mice by decreasing lipid synthesis and secretion of triglyceride-rich apoB-containing lipoproteins. Therefore, miR-30c coordinately reduces lipid biosynthesis and lipoprotein secretion to control hepatic and plasma lipids and might be useful in treating hyperlipidemias and associated disorders.
Collapse
Affiliation(s)
- James Soh
- School of Graduate Studies, Molecular and Cell Biology Program, State University of New York Downstate Medical Center, Brooklyn, New York, USA
| | | | | | | | | |
Collapse
|
16
|
Pan X, Munshi MK, Iqbal J, Queiroz J, Sirwi AA, Shah S, Younus A, Hussain MM. Circadian regulation of intestinal lipid absorption by apolipoprotein AIV involves forkhead transcription factors A2 and O1 and microsomal triglyceride transfer protein. J Biol Chem 2013; 288:20464-76. [PMID: 23729668 DOI: 10.1074/jbc.m113.473454] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have shown previously that Clock, microsomal triglyceride transfer protein (MTP), and nocturnin are involved in the circadian regulation of intestinal lipid absorption. Here, we clarified the role of apolipoprotein AIV (apoAIV) in the diurnal regulation of plasma lipids and intestinal lipid absorption in mice. Plasma triglyceride in apoAIV(-/-) mice showed diurnal variations similar to apoAIV(+/+) mice; however, the increases in plasma triglyceride at night were significantly lower in these mice. ApoAIV(-/-) mice absorbed fewer lipids at night and showed blunted response to daytime feeding. To explain reasons for these lower responses, we measured MTP expression; intestinal MTP was low at night, and its induction after food entrainment was less in apoAIV(-/-) mice. Conversely, apoAIV overexpression increased MTP mRNA in hepatoma cells, indicating transcriptional regulation. Mechanistic studies revealed that sequences between -204/-775 bp in the MTP promoter respond to apoAIV and that apoAIV enhances expression of FoxA2 and FoxO1 transcription factors and their binding to the identified cis elements in the MTP promoter at night. Knockdown of FoxA2 and FoxO1 abolished apoAIV-mediated MTP induction. Similarly, knockdown of apoAIV in differentiated Caco-2 cells reduced MTP, FoxA2, and FoxO1 mRNA levels, cellular MTP activity, and media apoB. Moreover, FoxA2 and FoxO1 expression showed diurnal variations, and their expression was significantly lower in apoAIV(-/-) mice. These data indicate that apoAIV modulates diurnal changes in lipid absorption by regulating forkhead transcription factors and MTP and that inhibition of apoAIV expression might reduce plasma lipids.
Collapse
Affiliation(s)
- Xiaoyue Pan
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA.
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Oikawa D, Kitamura A, Kinjo M, Iwawaki T. Direct association of unfolded proteins with mammalian ER stress sensor, IRE1β. PLoS One 2012; 7:e51290. [PMID: 23236464 PMCID: PMC3517461 DOI: 10.1371/journal.pone.0051290] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 11/01/2012] [Indexed: 12/13/2022] Open
Abstract
IRE1, an ER-localized transmembrane protein, plays a central role in the unfolded protein response (UPR). IRE1 senses the accumulation of unfolded proteins in its luminal domain and transmits a signal to the cytosolic side through its kinase and RNase domains. Although the downstream pathways mediated by two mammalian IRE1s, IRE1α and IRE1β, are well documented, their luminal events have not been fully elucidated. In particular, there have been no reports on how IRE1β senses the unfolded proteins. In this study, we performed a comparative analysis to clarify the luminal event mediated by the mammalian IRE1s. Confocal fluorescent microscopy using GFP-fused IRE1s revealed that IRE1β clustered into discrete foci upon ER stress. Also, fluorescence correlation spectroscopy (FCS) analysis in living cells indicated that the size of the IRE1β complex is robustly increased upon ER stress. Moreover, unlike IRE1α, the luminal domain of IRE1β showed anti-aggregation activity in vitro, and IRE1β was coprecipitated with the model unfolded proteins in cells. Strikingly, association with BiP was drastically reduced in IRE1β, while IRE1α was associated with BiP and dissociated upon ER stress. This is the first report indicating that, differently from IRE1α, the luminal event mediated by IRE1β involves direct interaction with unfolded proteins rather than association/dissociation with BiP, implying an intrinsic diversity in the sensing mechanism of mammalian sensors.
Collapse
Affiliation(s)
- Daisuke Oikawa
- Iwawaki lab, Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma, Japan
- Research Fellow of the Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo, Japan
- Iwawaki Initiative Research Unit, Advanced Science Institute, RIKEN, Wako, Saitama, Japan
- * E-mail: (DO); (TI)
| | - Akira Kitamura
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Kita-ku, Sapporo, Japan
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Kita-ku, Sapporo, Japan
| | - Takao Iwawaki
- Iwawaki lab, Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma, Japan
- Iwawaki Initiative Research Unit, Advanced Science Institute, RIKEN, Wako, Saitama, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- * E-mail: (DO); (TI)
| |
Collapse
|
18
|
Iqbal J, Queiroz J, Li Y, Jiang XC, Ron D, Hussain MM. Increased intestinal lipid absorption caused by Ire1β deficiency contributes to hyperlipidemia and atherosclerosis in apolipoprotein E-deficient mice. Circ Res 2012; 110:1575-84. [PMID: 22556338 DOI: 10.1161/circresaha.112.264283] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
RATIONALE High fasting serum lipid levels are significant risk factors for atherosclerosis. However, the contributions of postprandial excursions in serum lipoproteins to atherogenesis are less well-characterized. OBJECTIVE This study aims to delineate whether changes in intestinal lipid absorption associated with loss of inositol-requiring enzyme 1β (Ire1β) would affect the development of hyperlipidemia and atherosclerosis in Apoe(-/-) mice. METHODS AND RESULTS We used Ire1β-deficient mice to assess the contribution of intestinal lipid absorption to atherosclerosis. Here, we show that Ire1b(-/-)/Apoe(-/-) mice contain higher levels of intestinal microsomal triglyceride transfer protein, absorb more lipids, exhibit hyperlipidemia, and have higher levels of atherosclerotic plaques compared with Apoe(-/-) mice when fed chow and western diets. CONCLUSIONS These studies indicate that Ire1β regulates intestinal lipid absorption and that increased intestinal lipoprotein production contributes to atherosclerosis.
Collapse
Affiliation(s)
- Jahangir Iqbal
- Department of Cell Biology, Box 5, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Dai K, Hussain MM. NR2F1 disrupts synergistic activation of the MTTP gene transcription by HNF-4α and HNF-1α. J Lipid Res 2012; 53:901-908. [PMID: 22357705 DOI: 10.1194/jlr.m025130] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regulation of microsomal triglyceride transfer protein (MTP) expression mainly occurs at the transcriptional level. We have previously shown that MTTP gene expression was repressed in nondifferentiated intestinal cells by nuclear receptor 2 family 1 (NR2F1). However, mechanisms involved in the repression of MTP by NR2F1 were not elucidated. Here, we show that MTP expression requires hepatic nuclear factor (HNF)-4α transcription factor. Different HNF-1 proteins synergistically enhance MTP promoter activity along with HNF-4α by binding to different cis elements. NR2F1 does not alter individual effects of HNF-4α and HNF-1 proteins on the MTTP gene promoter. However, NR2F1 suppresses synergistic activation of the MTP promoter by HNF-4α/HNF-1α by binding to a direct repeat 1 (DR1) element. This suppression is further enhanced in the presence of nuclear receptor corepressor 1. In short, these studies identified a novel mechanism of MTP repression that involves binding of NR2F1 to the DR1 element and recruitment of corepressors. In this mechanism, NR2F1 does not affect activities of individual transcription factors; instead, it abrogates synergistic activation by HNF-4α and HNF-1 proteins.
Collapse
Affiliation(s)
- Kezhi Dai
- Departments of Cell Biology and Pediatrics, Program of Molecular and Cellular Biology, School of Graduate Studies, SUNY Downstate Medical Center, Brooklyn, NY
| | - M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, Program of Molecular and Cellular Biology, School of Graduate Studies, SUNY Downstate Medical Center, Brooklyn, NY.
| |
Collapse
|
20
|
Hussain MM, Rava P, Walsh M, Rana M, Iqbal J. Multiple functions of microsomal triglyceride transfer protein. Nutr Metab (Lond) 2012; 9:14. [PMID: 22353470 PMCID: PMC3337244 DOI: 10.1186/1743-7075-9-14] [Citation(s) in RCA: 182] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/21/2012] [Indexed: 02/08/2023] Open
Abstract
Microsomal triglyceride transfer protein (MTP) was first identified as a major cellular protein capable of transferring neutral lipids between membrane vesicles. Its role as an essential chaperone for the biosynthesis of apolipoprotein B (apoB)-containing triglyceride-rich lipoproteins was established after the realization that abetalipoproteinemia patients carry mutations in the MTTP gene resulting in the loss of its lipid transfer activity. Now it is known that it also plays a role in the biosynthesis of CD1, glycolipid presenting molecules, as well as in the regulation of cholesterol ester biosynthesis. In this review, we will provide a historical perspective about the identification, purification and characterization of MTP, describe methods used to measure its lipid transfer activity, and discuss tissue expression and function. Finally, we will review the role MTP plays in the assembly of apoB-lipoprotein, the regulation of cholesterol ester synthesis, biosynthesis of CD1 proteins and propagation of hepatitis C virus. We will also provide a brief overview about the clinical potentials of MTP inhibition.
Collapse
Affiliation(s)
- M Mahmood Hussain
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Paul Rava
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Meghan Walsh
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Muhammad Rana
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Jahangir Iqbal
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| |
Collapse
|
21
|
The chylomicron: relationship to atherosclerosis. Int J Vasc Med 2011; 2012:784536. [PMID: 22007304 PMCID: PMC3189596 DOI: 10.1155/2012/784536] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 08/08/2011] [Indexed: 12/20/2022] Open
Abstract
The B-containing lipoproteins are the transporters of cholesterol, and the evidence suggests that the apo B48-containing postprandial chylomicron particles and the triglyceride-rich very low density lipoprotein (VLDL) particles play an important part in the development of the plaque both directly and indirectly by their impact on LDL composition. The ratio of dietary to synthesised cholesterol is variable but tightly regulated: hence intervention with diet at best reduces serum cholesterol by <20% andusually <10%. Statins are the mainstay of cholesterol reduction therapy, but they increase cholesterol absorption, an example of the relationship between synthesis and absorption. Inhibition of cholesterol absorption with Ezetimibe, an inhibitor of Niemann Pick C1-like 1 (NPC1-L1), the major regulator of cholesterol absorption, increases cholesterol synthesis and hence the value of adding an inhibitor of cholesterol absorption to an inhibitor of cholesterol synthesis. Apo B48, the structural protein of the chylomicron particle, is synthesised in abundance so that the release of these particles is dependent on the amount of cholesterol and triglyceride available in the intestine. This paper will discuss cholesterol absorption and synthesis, chylomicron formation, and the effect of postprandial lipoproteins on factors involved in atherosclerosis.
Collapse
|
22
|
Hussain MM, Nijstad N, Franceschini L. Regulation of microsomal triglyceride transfer protein. ACTA ACUST UNITED AC 2011; 6:293-303. [PMID: 21808658 DOI: 10.2217/clp.11.21] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microsomal triglyceride transfer protein (MTP) facilitates the transport of dietary and endogenous fat by the intestine and liver by assisting in the assembly and secretion of triglyceride-rich apolipoprotein B-containing lipoproteins. Higher concentrations of apolipoprotein B lipoproteins predispose individuals to various cardiovascular and metabolic diseases such as atherosclerosis, diabetes, obesity and the metabolic syndrome. These can potentially be avoided by reducing MTP activity. In this article, we discuss regulation of MTP during development, cellular differentiation and diurnal variation. Furthermore, we focus on the regulation of MTP that occurs at transcriptional, post-transcriptional and post-translational levels. Transcriptional regulation of MTP depends on a few highly conserved cis-elements in the promoter. Several transcription factors that bind to these elements and either increase or decrease MTP expression have been identified. Additionally, MTP is regulated by macronutrients, hormones and other factors. This article will address the many ways in which MTP is regulated and advance the idea that reducing MTP levels, rather than its inhibition, might be an option to lower plasma lipids.
Collapse
Affiliation(s)
- M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, The State University of New York, Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA
| | | | | |
Collapse
|
23
|
Pan X, Zhang Y, Wang L, Hussain MM. Diurnal regulation of MTP and plasma triglyceride by CLOCK is mediated by SHP. Cell Metab 2010; 12:174-86. [PMID: 20674862 PMCID: PMC2925198 DOI: 10.1016/j.cmet.2010.05.014] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 04/02/2010] [Accepted: 05/26/2010] [Indexed: 12/11/2022]
Abstract
We examined the role of clock genes in the diurnal regulation of plasma triglyceride-rich apolipoprotein B-lipoproteins and their biosynthetic chaperone, microsomal triglyceride transfer protein (MTP). Clock(mt/mt) mice showed sustained hypertriglyceridemia and high MTP expression. CLOCK knockdown activated MTP promoter and reduced small heterodimer partner (SHP, NROB2). CLOCK upregulated SHP by binding to its E box. SHP suppressed MTP expression by binding to the HNF4alpha/LRH-1 at the MTP promoter. Cyclic expression of MTP after serum shock was abrogated by siCLOCK and siSHP. Plasma triglyceride and MTP showed reduced diurnal variations in Shp(-/-) mice. Whereas peaks and nadirs in SHP expression were inversely correlated with those of MTP, these changes were reduced in Clock(mt/mt) mice. Expression of Shp abrogated hypertriglyceridemia in Clock(mt/mt) mice. Together, these studies describe a role of Clock/Shp in the diurnal regulation of MTP and plasma triglyceride and indicate that disruptions in circadian regulation might cause hyperlipidemia.
Collapse
Affiliation(s)
- Xiaoyue Pan
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | | | | | | |
Collapse
|