1
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Cho SB. Comorbidity Genes of Alzheimer's Disease and Type 2 Diabetes Associated with Memory and Cognitive Function. Int J Mol Sci 2024; 25:2211. [PMID: 38396891 PMCID: PMC10889845 DOI: 10.3390/ijms25042211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/02/2024] [Accepted: 02/10/2024] [Indexed: 02/25/2024] Open
Abstract
Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) are comorbidities that result from the sharing of common genes. The molecular background of comorbidities can provide clues for the development of treatment and management strategies. Here, the common genes involved in the development of the two diseases and in memory and cognitive function are reviewed. Network clustering based on protein-protein interaction network identified tightly connected gene clusters that have an impact on memory and cognition among the comorbidity genes of AD and T2DM. Genes with functional implications were intensively reviewed and relevant evidence summarized. Gene information will be useful in the discovery of biomarkers and the identification of tentative therapeutic targets for AD and T2DM.
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Affiliation(s)
- Seong Beom Cho
- Department of Biomedical Informatics, College of Medicine, Gachon University, 38-13, Dokgeom-ro 3 Street, Namdon-gu, Incheon 21565, Republic of Korea
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2
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Helal M, Hany N, Maged M, Abdelaziz M, Osama N, Younan YW, Ismail Y, Abdelrahman R, Ragab M. Candidate genes for marker-assisted selection for growth, carcass and meat quality traits in rabbits. Anim Biotechnol 2022; 33:1691-1710. [PMID: 33872113 DOI: 10.1080/10495398.2021.1908315] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Growth and meat production are the most relevant targets for animal breeders, there are strong relationships between animal growth regulation, body composition and meat quality. Therefore, it is essential to identify the genetic factors that are controlling growth, carcass, and meat quality traits and to explore the correlations between identified genes of those traits. Identification of candidate genes may shift rabbit breeding from classical to modern approaches, which offer great potential to accelerate genetic improvement plans, especially in developing countries. The current work reviews several genes and mutations affecting growth, carcass and meat quality traits. These candidate genes and mutations can be incorporated into MAS programs to improve rabbit breeds especially local breeds, provided that a reasonable proportion of trait additive genetic variance is explained by the significant marker. Furthermore, we highlighted the indispensable need for more researches investigating candidate genes for different traits.
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Affiliation(s)
- Mostafa Helal
- Department of Animal Production, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Nora Hany
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Marya Maged
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Mariam Abdelaziz
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Nourhan Osama
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Youstina W Younan
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Youssef Ismail
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Ramah Abdelrahman
- Biotechnolgy Program, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Mohamed Ragab
- Department of Poultry Production, Faculty of Agriculture, Kafr El-Sheikh University, Kafr El-Sheikh, Egypt
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3
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Dou J, Luo H, Sammad A, Lou W, Wang D, Schenkel F, Yu Y, Fang L, Wang Y. Epigenomics of rats' liver and its cross-species functional annotation reveals key regulatory genes underlying short term heat-stress response. Genomics 2022; 114:110449. [PMID: 35985612 DOI: 10.1016/j.ygeno.2022.110449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/28/2022] [Accepted: 08/12/2022] [Indexed: 11/04/2022]
Abstract
Molecular responses to heat stress are multifaceted and under a complex cellular post-transcriptional control. This study explores the epigenetic and transcriptional alterations induced by heat stress (42 °C for 120 min) in the liver of rats, by integrating ATAC-seq, RNA-Seq, and WGBS information. Out of 2586 differential ATAC-seq peaks induced by heat stress, 36 up-regulated and 22 down-regulated transcript factors (TFs) are predicted, such as Cebpα, Foxa2, Foxo4, Nfya and Sp3. Furthermore, 150,189 differentially methylated regions represent 2571 differentially expressed genes (DEGs). By integrating all data, 45 DEGs are concluded as potential heat stress response markers in rats. To comprehensively annotate and narrow down predicted markers, they are integrated with GWAS results of heat stress parameters in cows, and PheWAS data in humans. Besides better understanding of heat stress responses in mammals, INSR, MAPK8, RHPN2 and BTBD7 are proposed as candidate markers for heat stress in mammals.
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Affiliation(s)
- Jinhuan Dou
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Hanpeng Luo
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Abdul Sammad
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Wenqi Lou
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Di Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Flavio Schenkel
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, N1G 2W1 Guelph, Ontario, Canada
| | - Ying Yu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
| | - Lingzhao Fang
- MRC Human Genetics Unit at the Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom.
| | - Yachun Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory of Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
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4
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Grasso P. Harnessing the Power of Leptin: The Biochemical Link Connecting Obesity, Diabetes, and Cognitive Decline. Front Aging Neurosci 2022; 14:861350. [PMID: 35527735 PMCID: PMC9072663 DOI: 10.3389/fnagi.2022.861350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/21/2022] [Indexed: 12/02/2022] Open
Abstract
In this review, the current understanding of leptin’s role in energy balance, glycemic regulation, and cognitive function is examined, and its involvement in maintaining the homeostatic “harmony” of these physiologies is explored. The effects of exercise on circulating leptin levels are summarized, and the results of clinical application of leptin to metabolic disease and neurologic dysfunction are reviewed. Finally, pre-clinical evidence is presented which suggests that synthetic peptide leptin mimetics may be useful in resolving not only the leptin resistance associated with common obesity and other elements of metabolic syndrome, but also the peripheral insulin resistance characterizing type 2 diabetes mellitus, and the central insulin resistance associated with certain neurologic deficits in humans.
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Affiliation(s)
- Patricia Grasso
- Department of Medicine, Albany Medical College, Albany, NY, United States
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
- *Correspondence: Patricia Grasso,
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5
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Rodríguez-Valentín R, Torres-Mejía G, Martínez-Matsushita L, Angeles-Llerenas A, Gómez-Flores-Ramos L, Wolff RK, Baumgartner KB, Hines LM, Ziv E, Flores-Luna L, Sánchez-Zamorano LM, Ortiz-Panozo E, Slattery ML. Energy homeostasis genes modify the association between serum concentrations of IGF-1 and IGFBP-3 and breast cancer risk. Sci Rep 2022; 12:1837. [PMID: 35115550 PMCID: PMC8813998 DOI: 10.1038/s41598-022-05496-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/17/2021] [Indexed: 02/08/2023] Open
Abstract
Breast cancer is a multifactorial disease in which the interplay among multiple risk factors remains unclear. Energy homeostasis genes play an important role in carcinogenesis and their interactions with the serum concentrations of IGF-1 and IGFBP-3 on the risk of breast cancer have not yet been investigated. The aim of this study was to assess the modifying effect of the genetic variation in some energy homeostasis genes on the association of serum concentrations of IGF-1 and IGFBP-3 with breast cancer risk. We analyzed 78 SNPs from 10 energy homeostasis genes in premenopausal women from the 4-Corner’s Breast Cancer Study (61 cases and 155 controls) and the Mexico Breast Cancer Study (204 cases and 282 controls). After data harmonization, 71 SNPs in HWE were included for interaction analysis. Two SNPs in two genes (MBOAT rs13272159 and NPY rs16131) showed an effect modification on the association between IGF-1 serum concentration and breast cancer risk (Pinteraction < 0.05, adjusted Pinteraction < 0.20). In addition, five SNPs in three genes (ADIPOQ rs182052, rs822391 and rs7649121, CARTPT rs3846659, and LEPR rs12059300) had an effect modification on the association between IGFBP-3 serum concentration and breast cancer risk (Pinteraction < 0.05, adjusted Pinteraction < 0.20). Our findings showed that variants of energy homeostasis genes modified the association between the IGF-1 or IGFBP-3 serum concentration and breast cancer risk in premenopausal women. These findings contribute to a better understanding of this multifactorial pathology.
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Affiliation(s)
- Rocío Rodríguez-Valentín
- Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico
| | - Gabriela Torres-Mejía
- Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico.
| | | | - Angélica Angeles-Llerenas
- Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico
| | - Liliana Gómez-Flores-Ramos
- Cátedras CONACYT-Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico
| | - Roger K Wolff
- Department of Medicine, University of Utah, Salt Lake City, UT, 84108, USA
| | - Kathy B Baumgartner
- Department of Epidemiology and Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, 40202, USA
| | - Lisa M Hines
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Elad Ziv
- Department of Medicine, Institute of Human Genetics, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Lourdes Flores-Luna
- Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico
| | - Luisa Ma Sánchez-Zamorano
- Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico
| | - Eduardo Ortiz-Panozo
- Center for Population Health Research, National Institute of Public Health, 62100, Cuernavaca, Morelos, Mexico
| | - Martha L Slattery
- Department of Medicine, University of Utah, Salt Lake City, UT, 84108, USA
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6
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Intervertebral Disc and Adipokine Leptin-Loves Me, Loves Me Not. Int J Mol Sci 2020; 22:ijms22010375. [PMID: 33396484 PMCID: PMC7795371 DOI: 10.3390/ijms22010375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 12/25/2022] Open
Abstract
Leptin—the most famous adipose tissue-secreted hormone—in the human body is mostly observed in a negative connotation, as the hormone level increases with the accumulation of body fat. Nowadays, fatness is becoming another normal body shape. Fatness is burdened with numerous illnesses—including low back pain and degenerative disease of lumbar intervertebral disc (IVD). IVD degeneration and IVD inflammation are two indiscerptible phenomena. Irrespective of the underlying pathophysiological background (trauma, obesity, nutrient deficiency), the inflammation is crucial in triggering IVD degeneration. Leptin is usually depicted as a proinflammatory adipokine. Many studies aimed at explaining the role of leptin in IVD degeneration, though mostly in in vitro and on animal models, confirmed leptin’s “bad reputation”. However, several studies found that leptin might have protective role in IVD metabolism. This review examines the current literature on the metabolic role of different depots of adipose tissue, with focus on leptin, in pathogenesis of IVD degeneration.
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7
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Leptin in hippocampus mediates benefits of mild exercise by an antioxidant on neurogenesis and memory. Proc Natl Acad Sci U S A 2019; 116:10988-10993. [PMID: 31085646 DOI: 10.1073/pnas.1815197116] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Regular exercise and dietary supplements with antioxidants each have the potential to improve cognitive function and attenuate cognitive decline, and, in some cases, they enhance each other. Our current results reveal that low-intensity exercise (mild exercise, ME) and the natural antioxidant carotenoid astaxanthin (AX) each have equivalent beneficial effects on hippocampal neurogenesis and memory function. We found that the enhancement by ME combined with AX in potentiating hippocampus-based plasticity and cognition is mediated by leptin (LEP) made and acting in the hippocampus. In assessing the combined effects upon wild-type (WT) mice undergoing ME with or without an AX diet for four weeks, we found that, when administrated alone, ME and AX separately enhanced neurogenesis and spatial memory, and when combined they were at least additive in their effects. DNA microarray and bioinformatics analyses revealed not only the up-regulation of an antioxidant gene, ABHD3, but also that the up-regulation of LEP gene expression in the hippocampus of WT mice with ME alone is further enhanced by AX. Together, they also increased hippocampal LEP (h-LEP) protein levels and enhanced spatial memory mediated through AKT/STAT3 signaling. AX treatment also has direct action on human neuroblastoma cell lines to increase cell viability associated with increased LEP expression. In LEP-deficient mice (ob/ob), chronic infusion of LEP into the lateral ventricles restored the synergy. Collectively, our findings suggest that not only h-LEP but also exogenous LEP mediates effects of ME on neural functions underlying memory, which is further enhanced by the antioxidant AX.
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8
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Marwarha G, Claycombe-Larson K, Lund J, Ghribi O. Palmitate-Induced SREBP1 Expression and Activation Underlies the Increased BACE 1 Activity and Amyloid Beta Genesis. Mol Neurobiol 2018; 56:5256-5269. [PMID: 30569418 DOI: 10.1007/s12035-018-1451-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 12/07/2018] [Indexed: 12/22/2022]
Abstract
Numerous cross-sectional and longitudinal studies have implicated saturated fat-enriched diets in the etio-pathogenesis of Alzheimer's disease (AD). Emerging evidence shows that saturated fat-enriched diets, such as palmitate-enriched diets, increase amyloid-beta (Aβ) production, the histopathological hallmark of AD. However, the molecular mechanisms that underlie the deleterious effects of palmitate-enriched diets in the augmentation of Aβ genesis are yet to be characterized. Sterol response element binding protein 1 (SREBP1) is a transcription factor that is modulated by saturated fatty acids, such as palmitate, and consequently regulates the expression of genes that code for proteins involved in almost all facets of lipid metabolism. Herein, we determined the role of changes in SREBP1 expression and transcriptional activity in the palmitate-induced effects on Aβ genesis and BACE1 expression, the enzyme that catalyzes the rate-limiting step in Aβ biosynthesis. We demonstrate that palmitate-induced SREBP1 activation directly regulates BACE1 expression at the transcriptional level in the mouse hippocampus and mouse Neuro-2a (N2a) neuroblastoma cells. Chromatin immunoprecipitation (ChIP) studies show that palmitate increases the binding of SREBP1 to the Bace1 promoter region in the mouse hippocampus and mouse N2a neuroblastoma cells. Ectopic expression of the dominant negative SREBP1 mutant and knocking-down SREBP1 expression significantly reduced the palmitate-induced increase in BACE1 expression and subsequent Aβ genesis in mouse N2a neuroblastoma cells. Our study unveils SREBP1 activation as a novel molecular player in the palmitate-induced upregulation of BACE1 expression and subsequent Aβ genesis.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, 1301 North Columbia Road, Grand Forks, ND, 58202, USA
| | - Kate Claycombe-Larson
- U.S. Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND, 58203, USA
| | - Jonah Lund
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, 1301 North Columbia Road, Grand Forks, ND, 58202, USA
| | - Othman Ghribi
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, 1301 North Columbia Road, Grand Forks, ND, 58202, USA.
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9
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Schommer J, Marwarha G, Nagamoto-Combs K, Ghribi O. Palmitic Acid-Enriched Diet Increases α-Synuclein and Tyrosine Hydroxylase Expression Levels in the Mouse Brain. Front Neurosci 2018; 12:552. [PMID: 30127714 PMCID: PMC6087752 DOI: 10.3389/fnins.2018.00552] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/20/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Accumulation of the α-synuclein (α-syn) protein and depletion of dopaminergic neurons in the substantia nigra are hallmarks of Parkinson's disease (PD). Currently, α-syn is under scrutiny as a potential pathogenic factor that may contribute to dopaminergic neuronal death in PD. However, there is a significant gap in our knowledge on what causes α-syn to accumulate and dopaminergic neurons to die. It is now strongly suggested that the nature of our dietary intake influences both epigenetic changes and disease-related genes and may thus potentially increase or reduce our risk of developing PD. Objective: In this study, we determined the extent to which a 3 month diet enriched in the saturated free fatty acid palmitate (PA) influences levels of α-syn and tyrosine hydroxylase, the rate limiting enzyme in dopamine synthesis in mice brains. Methods: We fed the m-Thy1-αSyn (m-Thy1) mouse model for PD and its matched control, the B6D2F1/J (B6D2) mouse a PA-enriched diet or a normal diet for 3 months. Levels of α-syn, tyrosine hydroxylase, and the biogenic amines dopamine and dopamine metabolites, serotonin and noradrenaline were determined. Results: We found that the PA-enriched diet induces an increase in α-syn and TH protein and mRNA expression levels in m-Thy1 transgenic mice. We also show that, while it didn't affect levels of biogenic amine content in the B6D2 mice, the PA-enriched diet significantly reduces dopamine metabolites and increases the level of serotonin in m-Thy1 mice. Conclusion: Altogether, our results demonstrate that a diet rich in the saturated fatty acid palmitate can modulate levels of α-syn, TH, dopamine, and serotonin which all are proteins and neurochemicals that play key roles in increasing or reducing the risk for many neurodegenerative diseases including PD.
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Affiliation(s)
- Jared Schommer
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Gurdeep Marwarha
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Kumi Nagamoto-Combs
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Othman Ghribi
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
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10
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Marwarha G, Schommer J, Lund J, Schommer T, Ghribi O. Palmitate-induced C/EBP homologous protein activation leads to NF-κB-mediated increase in BACE1 activity and amyloid beta genesis. J Neurochem 2018; 144:761-779. [PMID: 29315574 PMCID: PMC6371812 DOI: 10.1111/jnc.14292] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/29/2017] [Accepted: 12/23/2017] [Indexed: 12/12/2022]
Abstract
The etiology of Alzheimer's disease (AD) is egregiously comprehended, but epidemiological studies have posited that diets rich in the saturated fatty acid palmitic acid (palmitate) are a significant risk factor. The production and accumulation of amyloid beta peptide (Aβ) is considered the core pathological molecular event in the pathogenesis of AD. The rate-limiting step in Aβ genesis from amyloid-β precursor protein (AβPP) is catalyzed by the enzyme β-site amyloid precursor protein cleaving enzyme 1 (BACE1), the expression and enzymatic activity of which is significantly up-regulated in the AD brain. In this study, we determined the molecular mechanisms that potentially underlie the palmitate-induced up-regulation in BACE1 expression and augmented Aβ production. We demonstrate that a palmitate-enriched diet and exogenous palmitate treatment evoke an increase in BACE1 expression and activity leading to enhanced Aβ genesis in the mouse brain and SH-SY5Y-APPSwe cells, respectively, through the activation of the transcription factor NF-κB. Chromatin immunoprecipitation (ChIP) assays and luciferase reporter assays revealed that palmitate enhances BACE1 expression by increasing the binding of NF-κB in the BACE1 promoter followed by an enhancement in the transactivation of the BACE1 promoter. Elucidation and delineation of upstream molecular events unveiled a critical role of the endoplasmic reticulum stress-associated transcription factor, C/EBP homologous protein (CHOP) in the palmitate-induced NF-κB activation, as CHOP knock-down cells and Chop-/- mice do not exhibit the same degree of NF-κB activation in response to the palmitate challenge. Our study delineates a novel CHOP-NF-κB signaling pathway that mediates palmitate-induced up-regulation of BACE1 expression and Aβ genesis.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203
| | - Jared Schommer
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203
| | - Jonah Lund
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203
| | - Trevor Schommer
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203
| | - Othman Ghribi
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203
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11
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Lambertz IU, Luo L, Berton TR, Schwartz SL, Hursting SD, Conti CJ, Fuchs-Young R. Early Exposure to a High Fat/High Sugar Diet Increases the Mammary Stem Cell Compartment and Mammary Tumor Risk in Female Mice. Cancer Prev Res (Phila) 2017; 10:553-562. [DOI: 10.1158/1940-6207.capr-17-0131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/21/2017] [Accepted: 08/30/2017] [Indexed: 11/16/2022]
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12
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Marwarha G, Rostad S, Lilek J, Kleinjan M, Schommer J, Ghribi O. Palmitate Increases β-site AβPP-Cleavage Enzyme 1 Activity and Amyloid-β Genesis by Evoking Endoplasmic Reticulum Stress and Subsequent C/EBP Homologous Protein Activation. J Alzheimers Dis 2017; 57:907-925. [PMID: 28304295 PMCID: PMC5389045 DOI: 10.3233/jad-161130] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Epidemiological studies implicate diets rich in saturated free fatty acids (sFFA) as a potential risk factor for developing Alzheimer's disease (AD). In particular, high plasma levels of the sFFA palmitic acid (palmitate) were shown to inversely correlate with cognitive function. However, the cellular mechanisms by which sFFA may increase the risk for AD are not well known. Endoplasmic reticulum (ER) stress has emerged as one of the signaling pathways initiating and fostering the neurodegenerative changes in AD by increasing the aspartyl protease β-site AβPP cleaving enzyme 1 (BACE1) and amyloid-β (Aβ) genesis. In this study, we determined the extent to which palmitate increases BACE1 and Aβ levels in vitro and in vivo as well as the potential role of ER stress as cellular mechanism underlying palmitate effects. We demonstrate, in palmitate-treated SH-SY5Y neuroblastoma cells and in the hippocampi of palmitate-enriched diet-fed mice, that palmitate evokes the activation of the C/EBP Homologous Protein (CHOP), a transcription factor that is specifically responsive to ER stress. Induction of CHOP expression is associated with increased BACE1 mRNA, protein and activity levels, and subsequent enhanced amyloidogenic processing of amyloid-β protein precursor (AβPP) that culminates in a substantial increase in Aβ genesis. We further show that CHOP is an indispensable molecular mediator of palmitate-induced upregulation in BACE1 activity and Aβ genesis. Indeed, we show that Chop-/- mice and CHOP knocked-down SH-SY5Y neuroblastoma cells do not exhibit the same commensurate degree of palmitate-induced increase in BACE1 expression levels and Aβ genesis.
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Affiliation(s)
| | | | | | | | | | - Othman Ghribi
- Correspondence to: Dr. Othman Ghribi, Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, North Dakota 58202, USA. Tel.: +1 701 777 2522; Fax: +1 701 777 4490; E-mail:
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13
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Marwarha G, Claycombe-Larson K, Schommer J, Ghribi O. Maternal low-protein diet decreases brain-derived neurotrophic factor expression in the brains of the neonatal rat offspring. J Nutr Biochem 2017; 45:54-66. [PMID: 28432877 PMCID: PMC5466833 DOI: 10.1016/j.jnutbio.2017.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 02/08/2017] [Accepted: 03/16/2017] [Indexed: 01/15/2023]
Abstract
Prenatal exposure to a maternal low-protein (LP) diet has been known to cause cognitive impairment, learning and memory deficits. However, the underlying mechanisms have not been identified. Herein, we demonstrate that a maternal LP diet causes, in the brains of the neonatal rat offspring, an attenuation in the basal expression of the brain-derived neurotrophic factor (BDNF), a neurotrophin indispensable for learning and memory. Female rats were fed either a 20% normal protein (NP) diet or an 8% LP 3 weeks before breeding and during the gestation period. Maternal LP diet caused a significant reduction in the Bdnf expression in the brains of the neonatal rats. We further found that the maternal LP diet reduced the activation of the cAMP/protein kinase A/cAMP response element binding protein (CREB) signaling pathway. This reduction was associated with a significant decrease in CREB binding to the Bdnf promoters. We also show that prenatal exposure to the maternal LP diet results in an inactive or repressed exon I and exon IV promoter of the Bdnf gene in the brain, as evidenced by fluxes in signatory hallmarks in the enrichment of acetylated and trimethylated histones in the nucleosomes that envelop the exon I and exon IV promoters, causing the Bdnf gene to be refractory to transactivation. Our study is the first to determine the impact of a maternal LP diet on the basal expression of BDNF in the brains of the neonatal rats exposed prenatally to an LP diet.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Kate Claycombe-Larson
- U.S. Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58203, USA
| | - Jared Schommer
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Othman Ghribi
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA.
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14
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Abstract
Organotypic slicing of brain tissue from young rodents has been used as a powerful model system for biomedical research [1], [2], [3]. Organotypic slicing complements cell culture and in vivo studies in multiple facets. This system can be useful for investigating manipulation of cellular signaling pathways without the hindrance of the blood-brain barrier while sacrificing fewer animals in the process. It also allows for preserved cellular connectivity and local intact circuitry which is a drawback of isolated cell cultures. Studies on age-related diseases have mainly used embryonic or early postnatal organotypic slice tissue. Excluding synaptic plasticity studies that are usually carried-out over a few hours and use adult mice or rats, a handful of studies performed on adult animals have had success for survival of slices [4], [5]. Here we describe a method for culturing organotypic slices with high viability from hippocampus of aged mice and rabbits. Our method permits slices from mice as old as 16 months and rabbits as old as years of age to survive ex vivo up to 8 weeks [6], [7], [8], [9]. Such a slice system may be relevant to investigating age-related brain diseases.
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15
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Uysal N, Agilkaya S, Sisman AR, Camsari UM, Gencoglu C, Dayi A, Aksu I, Baykara B, Cingoz S, Kiray M. Exercise increases leptin levels correlated with IGF-1 in hippocampus and prefrontal cortex of adolescent male and female rats. J Chem Neuroanat 2017; 81:27-33. [DOI: 10.1016/j.jchemneu.2017.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 01/19/2017] [Accepted: 02/02/2017] [Indexed: 02/07/2023]
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16
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Vieira MNN, Lyra E Silva NM, Ferreira ST, De Felice FG. Protein Tyrosine Phosphatase 1B (PTP1B): A Potential Target for Alzheimer's Therapy? Front Aging Neurosci 2017; 9:7. [PMID: 28197094 PMCID: PMC5281585 DOI: 10.3389/fnagi.2017.00007] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/12/2017] [Indexed: 01/21/2023] Open
Abstract
Despite significant advances in current understanding of mechanisms of pathogenesis in Alzheimer's disease (AD), attempts at drug development based on those discoveries have failed to translate into effective, disease-modifying therapies. AD is a complex and multifactorial disease comprising a range of aberrant cellular/molecular processes taking part in different cell types and brain regions. As a consequence, therapeutics for AD should be able to block or compensate multiple abnormal pathological events. Here, we examine recent evidence that inhibition of protein tyrosine phosphatase 1B (PTP1B) may represent a promising strategy to combat a variety of AD-related detrimental processes. Besides its well described role as a negative regulator of insulin and leptin signaling, PTB1B recently emerged as a modulator of various other processes in the central nervous system (CNS) that are also implicated in AD. These include signaling pathways germane to learning and memory, regulation of synapse dynamics, endoplasmic reticulum (ER) stress and microglia-mediated neuroinflammation. We propose that PTP1B inhibition may represent an attractive and yet unexplored therapeutic approach to correct aberrant signaling pathways linked to AD.
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Affiliation(s)
- Marcelo N N Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Natalia M Lyra E Silva
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's UniversityKingston, ON, Canada
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17
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Jamal S, Goyal S, Shanker A, Grover A. Integrating network, sequence and functional features using machine learning approaches towards identification of novel Alzheimer genes. BMC Genomics 2016; 17:807. [PMID: 27756223 PMCID: PMC5070370 DOI: 10.1186/s12864-016-3108-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/20/2016] [Indexed: 01/01/2023] Open
Abstract
Background Alzheimer’s disease (AD) is a complex progressive neurodegenerative disorder commonly characterized by short term memory loss. Presently no effective therapeutic treatments exist that can completely cure this disease. The cause of Alzheimer’s is still unclear, however one of the other major factors involved in AD pathogenesis are the genetic factors and around 70 % risk of the disease is assumed to be due to the large number of genes involved. Although genetic association studies have revealed a number of potential AD susceptibility genes, there still exists a need for identification of unidentified AD-associated genes and therapeutic targets to have better understanding of the disease-causing mechanisms of Alzheimer’s towards development of effective AD therapeutics. Results In the present study, we have used machine learning approach to identify candidate AD associated genes by integrating topological properties of the genes from the protein-protein interaction networks, sequence features and functional annotations. We also used molecular docking approach and screened already known anti-Alzheimer drugs against the novel predicted probable targets of AD and observed that an investigational drug, AL-108, had high affinity for majority of the possible therapeutic targets. Furthermore, we performed molecular dynamics simulations and MM/GBSA calculations on the docked complexes to validate our preliminary findings. Conclusions To the best of our knowledge, this is the first comprehensive study of its kind for identification of putative Alzheimer-associated genes using machine learning approaches and we propose that such computational studies can improve our understanding on the core etiology of AD which could lead to the development of effective anti-Alzheimer drugs. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3108-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Salma Jamal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.,Department of Bioscience and Biotechnology, Banasthali University, Tonk, Rajasthan, 304022, India
| | - Sukriti Goyal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.,Department of Bioscience and Biotechnology, Banasthali University, Tonk, Rajasthan, 304022, India
| | - Asheesh Shanker
- Bioinformatics Programme, Centre for Biological Sciences, Central University of South Bihar, BIT Campus, Patna, Bihar, India
| | - Abhinav Grover
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
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18
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Marwarha G, Claycombe K, Schommer J, Collins D, Ghribi O. Palmitate-induced Endoplasmic Reticulum stress and subsequent C/EBPα Homologous Protein activation attenuates leptin and Insulin-like growth factor 1 expression in the brain. Cell Signal 2016; 28:1789-805. [PMID: 27555288 DOI: 10.1016/j.cellsig.2016.08.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/05/2016] [Accepted: 08/18/2016] [Indexed: 12/11/2022]
Abstract
The peptide hormones Insulin-like growth factor-1 (IGF1) and leptin mediate a myriad of biological effects - both in the peripheral and central nervous systems. The transcription of these two hormones is regulated by the transcription factor C/EBPα, which in turn is negatively regulated by the transcription factor C/EBP Homologous Protein (CHOP), a specific marker of endoplasmic reticulum (ER) stress. In the peripheral system, disturbances in leptin and IGF-1 levels are implicated in a variety of metabolic diseases including obesity, diabetes, atherosclerosis and cardiovascular diseases. Current research suggests a positive correlation between consumption of diets rich in saturated free fatty acids (sFFA) and metabolic diseases. Induction of ER stress and subsequent dysregulation in the expression levels of leptin and IGF-1 have been shown to mediate sFFA-induced metabolic diseases in the peripheral system. Palmitic acid (palmitate), the most commonly consumed sFFA, has been shown to be up-taken by the brain, where it may promote neurodegeneration. However, the extent to which palmitate induces ER stress in the brain and attenuates leptin and IGF1 expression has not been determined. We fed C57BL/6J mice a palmitate-enriched diet and determined effects on the expression levels of leptin and IGF1 in the hippocampus and cortex. We further determined the extent to which ER stress and subsequent CHOP activation mediate the palmitate effects on the transcription of leptin and IGF1. We demonstrate that palmitate induces ER stress and decreases leptin and IGF1 expression by inducing the expression of CHOP. The molecular chaperone 4-phenylbutyric acid (4-PBA), an inhibitor of ER stress, precludes the palmitate-evoked down-regulation of leptin and IGF1 expression. Furthermore, the activation of CHOP in response to ER stress is pivotal in the attenuation of leptin and IGF1 expression as knocking-down CHOP in mice or in SH-SY5Y and Neuro-2a (N2a) cells rescues the palmitate-induced mitigation in leptin and IGF1 expression. Our study implicates for the first time ER stress-induced CHOP activation in the brain as a mechanistic link in the palmitate-induced negative regulation of leptin and IGF1, two neurotrophic cytokines that play an indispensable role in the mammalian brain.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Kate Claycombe
- U.S. Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58203, USA
| | - Jared Schommer
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - David Collins
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Othman Ghribi
- Department of Biomedical Sciences, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA.
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19
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McGuire MJ, Ishii M. Leptin Dysfunction and Alzheimer's Disease: Evidence from Cellular, Animal, and Human Studies. Cell Mol Neurobiol 2016; 36:203-17. [PMID: 26993509 DOI: 10.1007/s10571-015-0282-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/01/2015] [Indexed: 12/13/2022]
Abstract
There is accumulating evidence from epidemiological studies that changes in body weight are associated with Alzheimer's disease (AD) from mid-life obesity increasing the risk of developing AD to weight loss occurring at the earliest stages of AD. Therefore, factors that regulate body weight are likely to influence the development and progression of AD. The adipocyte-derived hormone leptin has emerged as a major regulator of body weight mainly by activating hypothalamic neural circuits. Leptin also has several pleotropic effects including regulating cognitive function and having neuroprotective effects, suggesting a potential link between leptin and AD. Here, we will examine the relationship between leptin and AD by reviewing the recent evidence from cellular and animal models to human studies. We present a model where leptin has a bidirectional role in AD. Not only can alterations in leptin levels and function worsen cognitive decline and progression of AD pathology, but AD pathology, in of itself, can disrupt leptin signaling, which together would lead to a downward spiral of progressive neurodegeneration and worsening body weight and systemic metabolic deficits. Collectively, these studies serve as a framework to highlight the importance of understanding the molecular mechanisms underlying the body weight and systemic metabolic deficits in AD, which has the potential to open new avenues that may ultimately lead to novel therapeutic targets and diagnostic tools.
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Affiliation(s)
- Matthew J McGuire
- Feil Family Brain and Mind Research Institute, Joan and Sanford I. Weill Medical College of Cornell University, New York, NY, 10065, USA
| | - Makoto Ishii
- Feil Family Brain and Mind Research Institute, Joan and Sanford I. Weill Medical College of Cornell University, New York, NY, 10065, USA.
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20
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Ghasemi M, Zendehbad B, Zabihi H, Hosseini M, Hadjzadeh MAR, Hayatdavoudi P. Beneficial Effect of Leptin on Spatial Learning and Memory in Streptozotocin-Induced Diabetic Rats. Balkan Med J 2016; 33:102-7. [PMID: 26966625 DOI: 10.5152/balkanmedj.2015.15084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 08/20/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Diabetes mellitus is a chronic disease which may be accompanied by cognitive impairments. The expression of the obesity gene (ob) is decreased in insulin-deficient diabetic animals and increased after the administration of insulin or leptin. Plasma leptin levels are reduced in the streptozotocin (STZ)-induced diabetic rats. Therefore, the deleterious effects of diabetes on memory may be due to the reduction of leptin. AIMS Investigate the effect of subcutaneous injection of leptin on spatial learning and memory in STZ-induced diabetic rats. STUDY DESIGN Animal experimentation. METHODS The rats were divided into three groups: 1-control, 2- diabetic, and 3- diabetic-leptin. Diabetes was induced in groups 2 and 3 by STZ injection (55 mg/kg) intraperitoneally (i.p). The animals received leptin (0.1 mg/kg) or saline subcutaneously (s.c) for 10 days before behavioral studies. Then, they were examined in the Morris water maze over 3 blocks after 3 days of the last injection of leptin. RESULTS The travelled path length and time spent to reach the platform significantly increased in the diabetic group (p<0.001) and decreased with leptin treatment (p<0.01 & p<0.001 respectively); also, a significant increase in path length and time was observed between the diabetic-leptin group and the diabetic group (p<0.01, p<0.001, respectively) in the probe test. CONCLUSION Leptin can exert positive effects on memory impairments in diabetic rats.
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Affiliation(s)
- Mohsen Ghasemi
- Department of Physiology, North Khorasan University of Medical Sciences Faculty of Medicine, Bojnurd, Iran
| | - Bamdad Zendehbad
- Department of Physiology, Neurocognitive Research Center, Mashhad University of Medical Sciences Faculty of Medicine, Mashhad, Iran
| | - Hoda Zabihi
- Department of Physiology, Neurocognitive Research Center, Mashhad University of Medical Sciences Faculty of Medicine, Mashhad, Iran
| | - Mahmoud Hosseini
- Department of Physiology, Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences Faculty of Medicine, Mashhad, Iran
| | - Mousa Al Reza Hadjzadeh
- Department of Physiology, Neurocognitive Research Center, Mashhad University of Medical Sciences Faculty of Medicine, Mashhad, Iran
| | - Parichehr Hayatdavoudi
- Department of Physiology, Neurocognitive Research Center, Mashhad University of Medical Sciences Faculty of Medicine, Mashhad, Iran
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Perianes-Cachero A, Canelles S, Aguado-Llera D, Frago LM, Toledo-Lobo MV, Carrera I, Cacabelos R, Chowen JA, Argente J, Arilla-Ferreiro E, Barrios V. Reduction in Aβ-induced cell death in the hippocampus of 17β-estradiol-treated female rats is associated with an increase in IGF-I signaling and somatostatinergic tone. J Neurochem 2015; 135:1257-71. [DOI: 10.1111/jnc.13381] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 09/11/2015] [Accepted: 09/14/2015] [Indexed: 12/23/2022]
Affiliation(s)
- Aránzazu Perianes-Cachero
- Neurobiochemistry Group; Unit of Biochemistry and Molecular Biology; Facultad de Medicina; Universidad de Alcalá; Alcalá de Henares Spain
| | - Sandra Canelles
- Department of Endocrinology; Hospital Infantil Universitario Niño Jesús; Instituto de Investigación La Princesa; Madrid Spain
- Centro de Investigación Biomédica en Red de Fisiopatología Obesidad y Nutrición (CIBEROBN); Instituto de Salud Carlos III; Madrid Spain
| | - David Aguado-Llera
- Neurobiochemistry Group; Unit of Biochemistry and Molecular Biology; Facultad de Medicina; Universidad de Alcalá; Alcalá de Henares Spain
| | - Laura M. Frago
- Department of Endocrinology; Hospital Infantil Universitario Niño Jesús; Instituto de Investigación La Princesa; Madrid Spain
- Centro de Investigación Biomédica en Red de Fisiopatología Obesidad y Nutrición (CIBEROBN); Instituto de Salud Carlos III; Madrid Spain
| | - María Val Toledo-Lobo
- Department of Biomedicine and Biotechnology; Universidad de Alcalá; Alcalá de Henares and Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS); Madrid Spain
| | - Iván Carrera
- Department of Neuroscience; EuroEspes Biotechnology; Polígono de Bergondo; A Coruña Spain
| | - Ramón Cacabelos
- EuroEspes Biomedical Research Center; Institute for CNS Disorders and Chair of Genomic Medicine; University of Camilo José Cela; Villanueva de la Cañada Spain
| | - Julie A Chowen
- Department of Endocrinology; Hospital Infantil Universitario Niño Jesús; Instituto de Investigación La Princesa; Madrid Spain
- Centro de Investigación Biomédica en Red de Fisiopatología Obesidad y Nutrición (CIBEROBN); Instituto de Salud Carlos III; Madrid Spain
| | - Jesús Argente
- Department of Endocrinology; Hospital Infantil Universitario Niño Jesús; Instituto de Investigación La Princesa; Madrid Spain
- Centro de Investigación Biomédica en Red de Fisiopatología Obesidad y Nutrición (CIBEROBN); Instituto de Salud Carlos III; Madrid Spain
| | - Eduardo Arilla-Ferreiro
- Neurobiochemistry Group; Unit of Biochemistry and Molecular Biology; Facultad de Medicina; Universidad de Alcalá; Alcalá de Henares Spain
| | - Vicente Barrios
- Department of Endocrinology; Hospital Infantil Universitario Niño Jesús; Instituto de Investigación La Princesa; Madrid Spain
- Centro de Investigación Biomédica en Red de Fisiopatología Obesidad y Nutrición (CIBEROBN); Instituto de Salud Carlos III; Madrid Spain
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Suman S, Kallakury BVS, Fornace AJ, Datta K. Protracted upregulation of leptin and IGF1 is associated with activation of PI3K/Akt and JAK2 pathway in mouse intestine after ionizing radiation exposure. Int J Biol Sci 2015; 11:274-83. [PMID: 25678846 PMCID: PMC4323367 DOI: 10.7150/ijbs.10684] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/25/2014] [Indexed: 01/15/2023] Open
Abstract
Ionizing radiation is a known risk factor for gastrointestinal (GI) pathologies including cancer. Hormones and related signaling crosstalk, which could contribute to radiation-induced persistent pathophysiologic changes in the small intestine and colon, remain to be explored. The current study assessed perturbation of GI homeostasis-related hormones and signaling pathways at the systemic as well as at the tissue level in small intestine and colon. Mice (6-8 week old C57BL/6J) were exposed to 2 Gy γ radiation, serum and tissue samples were collected, and insulin like growth factor 1 (IGF-1) and leptin signaling were assessed two or twelve months after radiation exposure. Serum levels of IGF-1, IGF binding protein 3 (IGFBP3), leptin, and adiponectin were altered at these times after irradiation. Radiation was associated with increased IGF1 receptor (IGF1R) and obesity (leptin) receptor (Ob-R), decreased adiponectin receptor 1 (Adipo-R1) and 2 (Adipo-R2), and increased Ki-67 levels in small intestine and colon at both time points. Immunoblot analysis further showed increased IGF1R and Ob-R, and decreased Adipo-R2. Additionally, upregulation of PI3K/Akt and JAK2 signaling, which are downstream of IGF1 and leptin, was also observed in irradiated samples at both time points. These results when considered along with increased cell proliferation in the small intestine and colon demonstrate for the first time that ionizing radiation can persistently increase IGF1 and leptin and activate downstream proliferative pathways, which may contribute to GI functional alterations and carcinogenesis.
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Affiliation(s)
- Shubhankar Suman
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, USA
| | - Bhaskar V S Kallakury
- 2. Department of Pathology, Georgetown University Medical Center, Washington DC, USA
| | - Albert J Fornace
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, USA. ; 3. Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia
| | - Kamal Datta
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, USA
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Wang Y, Wang YX, Liu T, Law PY, Loh HH, Qiu Y, Chen HZ. μ-Opioid receptor attenuates Aβ oligomers-induced neurotoxicity through mTOR signaling. CNS Neurosci Ther 2014; 21:8-14. [PMID: 25146548 DOI: 10.1111/cns.12316] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 12/19/2022] Open
Abstract
AIMS μ-opioid receptor (OPRM1) exerts many functions such as antinociception, neuroprotection, and hippocampal plasticity. A body of evidence has shown that OPRM1 activation could stimulate downstream effectors of mechanistic/mammalian target of rapamycin (mTOR). However, it is not clear whether OPRM1 protects neurons against β-amyloid peptide (Aβ) neurotoxicity through mTOR signaling. METHODS The effects of OPRM1 activation on Aβ oligomers-induced neurotoxicity were assessed by cell viability and neurite outgrowth assay in primary cultured cortical neurons. The activities of mTOR, protein kinase B (Akt) and p70 ribosomal S6 kinase (p70 S6k) upon OPRM1 activation by morphine were measured by immunoblotting their phosphorylation status. RESULTS Morphine dose-dependently attenuated Aβ oligomers-induced neurotoxicity. Aβ oligomers downregulated mTOR signaling. Morphine significantly rescued mTOR signaling by reversal of Aβ oligomers' effect on mTOR and its upstream signaling molecule Akt, as well as its downstream molecule p70 S6k. Moreover, the neuroprotective effect of morphine could be reversed by OPRM1 selective antagonist and phosphatidylinositol 3-kinases (PI3K), Akt and mTOR inhibitors. Furthermore, endogenous opioids-enkaphalins also attenuated Aβ oligomers-induced neurotoxicity. CONCLUSIONS Our findings demonstrated OPRM1 activation attenuated Aβ oligomers-induced neurotoxicity through mTOR signaling. It may provide new insight into the pathological process and useful strategy for therapeutic interventions against Aβ neurotoxicity.
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Affiliation(s)
- Yan Wang
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Marwarha G, Raza S, Meiers C, Ghribi O. Leptin attenuates BACE1 expression and amyloid-β genesis via the activation of SIRT1 signaling pathway. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1587-95. [PMID: 24874077 DOI: 10.1016/j.bbadis.2014.05.015] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/13/2014] [Accepted: 05/16/2014] [Indexed: 02/07/2023]
Abstract
The aspartyl protease β-site AβPP-cleaving enzyme 1 (BACE1) catalyzes the rate-limiting step in Aβ production, a peptide at the nexus of neurodegenerative cascades in Alzheimer Disease (AD). The adipocytokine leptin has been demonstrated to reduce Aβ production and decrease BACE1 activity and expression levels. However, the signaling cascades involved in the leptin-induced mitigation in Aβ levels and BACE1 expression levels have not been elucidated. We have demonstrated that the transcription factor nuclear factor - kappa B (NF-κB) positively regulates BACE1 transcription. NF-κB activity is tightly regulated by the mammalian sirtuin SIRT1. Multiple studies have cogently evinced that leptin activates the metabolic master regulator SIRT1. In this study, we determined the extent to which SIRT1 expression and activity regulate the leptin-induced attenuation in BACE1 expression and Aβ levels in cultured human neuroblastoma SH-SY5Y cells. This study also elucidated and delineated the signal transduction pathways involved in the leptin induced mitigation in BACE1 expression. Our results demonstrate for the first time that leptin attenuates the activation and transcriptional activity of NF-κB by reducing the acetylation of the p65 subunit in a SIRT1-dependent manner. Furthermore, our data shows that leptin reduces the NF-κB-mediated transcription of BACE1 and consequently reduces Amyloid-β genesis. Our study provides a valuable insight and a novel mechanism by which leptin reduces BACE1 expression and Amyloid-β production and may help design potential therapeutic interventions.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Shaneabbas Raza
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Craig Meiers
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Othman Ghribi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202, USA.
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25
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Kwak JW, Jeong H, Han SH, Kim Y, Son SM, Mook-Jung I, Hwang D, Park JW. Phosphokinase antibody arrays on dendron-coated surface. PLoS One 2014; 9:e96456. [PMID: 24802362 PMCID: PMC4011796 DOI: 10.1371/journal.pone.0096456] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 04/08/2014] [Indexed: 12/04/2022] Open
Abstract
Monitoring protein phosphorylation at the cellular level is important to understand the intracellular signaling. Among the phosphoproteomics methods, phosphokinase antibody arrays have emerged as preferred tools to measure well-characterized phosphorylation in the intracellular signaling. Here, we present a dendron-coated phosphokinase antibody array (DPA) in which the antibodies are immobilized on a dendron-coated glass slide. Self-assembly of conically shaped dendrons well-controlled in size and structure resulted in precisely controlled lateral spacing between the immobilized phosphosite-specific antibodies, leading to minimized steric hindrance and improved antigen-antibody binding kinetics. These features increased sensitivity, selectivity, and reproducibility in measured amounts of protein phosphorylation. To demonstrate the utility of the DPA, we generated the phosphorylation profiles of brain tissue samples obtained from Alzheimer's disease (AD) model mice. The analysis of the profiles revealed signaling pathways deregulated during the course of AD progression.
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Affiliation(s)
- Ju-Won Kwak
- Department of Chemistry, POSTECH, Pohang, Republic of Korea
| | - Hyobin Jeong
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, Republic of Korea
| | - Sun-Ho Han
- Department of Biochemistry and Biomedical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Youngkyu Kim
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, Republic of Korea
| | - Sung Min Son
- Department of Biochemistry and Biomedical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical Sciences, Seoul National University, Seoul, Republic of Korea
- * E-mail: (IM-J); (DH); (JWP)
| | - Daehee Hwang
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, Republic of Korea
- Center for Plant Aging Research, Institute for Basic Science, DGIST, Daegu, Republic of Korea
- * E-mail: (IM-J); (DH); (JWP)
| | - Joon Won Park
- Department of Chemistry, POSTECH, Pohang, Republic of Korea
- * E-mail: (IM-J); (DH); (JWP)
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Stegeman H, Kaanders JHAM, Verheijen MMG, Peeters WJM, Wheeler DL, Iida M, Grénman R, van der Kogel AJ, Span PN, Bussink J. Combining radiotherapy with MEK1/2, STAT5 or STAT6 inhibition reduces survival of head and neck cancer lines. Mol Cancer 2013; 12:133. [PMID: 24192080 PMCID: PMC3842630 DOI: 10.1186/1476-4598-12-133] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 10/31/2013] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Kinases downstream of growth factor receptors have been implicated in radioresistance and are, therefore, attractive targets to improve radiotherapy outcome in head and neck squamous cell carcinoma (HNSCC) patients. METHODS An antibody-based array was used to quantify the expression levels of multiple phospho-kinases involved in growth factor signaling in nine untreated or irradiated HNSCC lines. Radiosensitivity was assessed with clonogenic cell survival assays and correlated with the expression levels of the phospho-kinases. Inhibitors of the kinases that were associated with radiosensitivity were tested for their ability to increase radiosensitivity in the 3 most radioresistant HNSCC lines. RESULTS The basal expression of phosphorylated Yes, Src and STAT5A, and the expression after radiotherapy of phosphorylated AKT, MSK1/2, Src, Lyn, Fyn, Hck, and STAT6, were correlated with radiosensitivity in the panel of HNSCC lines. In combination with radiotherapy, inhibitors of AKT, p38 and Src Family Kinases (SFK) were variably able to reduce survival, whereas MEK1/2, STAT5 and STAT6 inhibition reduced survival in all cell lines. The combined effect of radiotherapy and the kinase inhibitors on cell survival was mostly additive, although also supra-additive effects were observed for AKT, MEK1/2, p38 and STAT5 inhibition. CONCLUSIONS Kinases of the AKT, MAPK, STAT and SFK pathways correlated with radiosensitivity in a panel of HNSCC lines. Particularly inhibitors against MEK1/2, STAT5 and STAT6 were able to decrease survival in combination with radiotherapy. Hence, inhibitors against these kinases have the potential to improve radiotherapy outcome in HNSCC patients and further research is warranted to confirm this in vivo.
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Affiliation(s)
- Hanneke Stegeman
- Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500, HB Nijmegen, The Netherlands.
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Harvey J. Leptin regulation of neuronal morphology and hippocampal synaptic function. Front Synaptic Neurosci 2013; 5:3. [PMID: 23964236 PMCID: PMC3734345 DOI: 10.3389/fnsyn.2013.00003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/12/2013] [Indexed: 12/14/2022] Open
Abstract
The central actions of the hormone leptin in regulating energy homeostasis via the hypothalamus are well documented. However, evidence is growing that this hormone can also modify the structure and function of synapses throughout the CNS. The hippocampus is a region of the forebrain that plays a crucial role in associative learning and memory and is an area also highly vulnerable to neurodegenerative processes. Recent studies indicate that leptin is a potential cognitive enhancer as it modulates the cellular processes underlying hippocampal-dependent learning and memory including dendritic morphology, glutamate receptor trafficking and activity-dependent synaptic plasticity. Here, we review the recent evidence implicating the hormone leptin as a key regulator of hippocampal synaptic function and discuss the role of leptin receptor-driven lipid signaling pathways involved in this process.
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Affiliation(s)
- Jenni Harvey
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee Dundee, UK
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Fadel JR, Jolivalt CG, Reagan LP. Food for thought: the role of appetitive peptides in age-related cognitive decline. Ageing Res Rev 2013; 12:764-76. [PMID: 23416469 DOI: 10.1016/j.arr.2013.01.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 01/25/2023]
Abstract
Through their well described actions in the hypothalamus, appetitive peptides such as insulin, orexin and leptin are recognized as important regulators of food intake, body weight and body composition. Beyond these metabolic activities, these peptides also are critically involved in a wide variety of activities ranging from modulation of immune and neuroendocrine function to addictive behaviors and reproduction. The neurological activities of insulin, orexin and leptin also include facilitation of hippocampal synaptic plasticity and enhancement of cognitive performance. While patients with metabolic disorders such as obesity and diabetes have greater risk of developing cognitive deficits, dementia and Alzheimer's disease (AD), the underlying mechanisms that are responsible for, or contribute to, age-related cognitive decline are poorly understood. In view of the importance of these peptides in metabolic disorders, it is not surprising that there is a greater focus on their potential role in cognitive deficits associated with aging. The goal of this review is to describe the evidence from clinical and pre-clinical studies implicating insulin, orexin and leptin in the etiology and progression of age-related cognitive decline. Collectively, these studies support the hypothesis that leptin and insulin resistance, concepts normally associated with the hypothalamus, are also applicable to the hippocampus.
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Affiliation(s)
- Jim R Fadel
- Department of Pharmacology, Physiology and Neuroscience, School of Medicine, University of South Carolina, 6439 Garners Ferry Road, Columbia, SC 29208, USA
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Cai Z, Yan LJ. Rapamycin, Autophagy, and Alzheimer's Disease. JOURNAL OF BIOCHEMICAL AND PHARMACOLOGICAL RESEARCH 2013; 1:84-90. [PMID: 23826514 PMCID: PMC3697866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive impairment and multiple pathological lesions. At the molecular level, AD is characterized by overt amyloid β (Aβ) production and tau hyper-phosphorylation. Hence, pharmacological agents that can attenuate Aβ accumulation and tau hyper-phosphorylation have potential promise for treatment of AD. Rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), is believed to be one of such pharmacological agents. It is neuroprotective in neurodegenerative diseases and its primary action is thought to be via enhancement of autophagy, a biological process that not only facilitates the clearance of mutant proteins but also significantly reduces the build-up of toxic protein aggregates such as Aβ. Since rapamycin enhancement of autophagy has been associated with abrogation of AD pathological processes such as clearance of Aβ and neurofibrillary tangles (NTFs) as well as reduction of tau hyper-phosphorylation and improvement of cognition, rapamycin is emerging as a potential therapeutic compound for AD.
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Affiliation(s)
- Zhiyou Cai
- Department of Neurology, Lu'an People's Hospital, the Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, Anhui Province, China, 237005
| | - Liang-Jun Yan
- Department of Pharmacology and Neuroscience and Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Marwarha G, Ghribi O. Leptin signaling and Alzheimer's disease. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2012; 1:245-265. [PMID: 23383396 PMCID: PMC3560472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/09/2012] [Indexed: 06/01/2023]
Abstract
Leptin, an adipocytokine produced in the peripheral system as well as in the brain, is implicated in obesity, food intake, glucose homeostasis, and energy expenditure. Leptin expression levels and signaling pathways may also be linked to the pathophysiology of neurodegenerative diseases including Alzheimer's disease. Epidemiological studies have demonstrated that higher circulating leptin levels are associated with lower risk of dementia including Alzheimer's disease, and lower circulating levels of leptin have been reported in patients with Alzheimer's disease. Leptin receptors are highly expressed in the hippocampus, a brain area involved in learning and memory and severely affected during the course of Alzheimer's disease. In laboratory studies, several in vivo and in vitro studies have shown that leptin supplementation decreases amyloid-β (Aβ) production and tau phosphorylation, two major biochemical events that play a key role in the pathogenesis of Alzheimer's disease. In this review, we will review the structure of leptin, the type of receptors of leptin in the brain, the various biological functions attributed to this adipocytokine, the signaling pathways that govern leptin actions, and the potential role of leptin in the pathophysiology of Alzheimer's disease. Leptin exerts its functions by binding to the leptin receptor (ObR). This binding can involve several signaling pathways including JAK/STAT pathway, ERK pathway and the PI3K/Akt/mTOR Pathway. Modulation of these pathways leads to the regulation of a multitude of functions that define the intricate involvement of leptin in various physiological tasks. In this review, we will specifically relate the potential involvement of leptin signaling in Alzheimer's disease based on work published by several laboratories including ours. All this work points to leptin as a possible target for developing supplementation therapies for reducing the progression of Alzheimer's disease.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences Grand Forks, North Dakota, 58202
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Marwarha G, Dasari B, Ghribi O. Endoplasmic reticulum stress-induced CHOP activation mediates the down-regulation of leptin in human neuroblastoma SH-SY5Y cells treated with the oxysterol 27-hydroxycholesterol. Cell Signal 2011; 24:484-492. [PMID: 21983012 DOI: 10.1016/j.cellsig.2011.09.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/23/2011] [Accepted: 09/25/2011] [Indexed: 10/17/2022]
Abstract
Epidemiological studies have suggested an inverse relationship between the adipocytokine leptin and the onset of Alzheimer's disease (AD), and leptin supplementation decreases amyloid-β (Aβ) production and tau phosphorylation (p-tau), two major biochemical events that play a key role in the pathogenesis of AD. We have previously shown that the cholesterol oxidized product 27-hydroxycholesterol (27-OHC) inhibits leptin expression, an effect that correlated with increased levels of Aβ and p-tau. We have also shown that 27-OHC induces endoplasmic reticulum (ER) stress, a cellular response that is implicated in AD and confers leptin resistance. However the extent to which ER stress is involved in 27-OHC-induced attenuation in leptin expression has not been determined. In this study we determined the involvement of ER stress in the 27-OHC-induced attenuation of leptin expression in SH-SY5Y human neuroblastoma cells. We demonstrate that 27-OHC-induced ER stress attenuates leptin expression by activating C/EBP Homologous Protein (CHOP) which negatively regulates C/EBPα, a transcription factor required for leptin expression. The molecular chaperone 4-phenylbutyric acid (4-PBA) precludes 27-OHC-evoked ER stress and down-regulation of leptin. Furthermore, we demonstrate that the activation of the transcription factor CHOP in response to ER stress is pivotal in the attenuation of leptin expression as knocking-down CHOP alleviates the attenuation in leptin expression. Our study implicates ER stress as the mechanistic link in the 27-OHC-induced negative regulation of leptin, a hormone that has potential therapeutic effects in AD by reducing Aβ and phosphorylated tau accumulation.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - Bhanu Dasari
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - Othman Ghribi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA.
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