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Sharma S, Verma S, Kapoor M, Saini A, Nehru B. Alzheimer's disease like pathology induced six weeks after aggregated amyloid-beta injection in rats: increased oxidative stress and impaired long-term memory with anxiety-like behavior. Neurol Res 2016; 38:838-50. [PMID: 27431920 DOI: 10.1080/01616412.2016.1209337] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Amyloid-beta (Aβ) peptide deposition into insoluble plaques is a pathological hallmark of Alzheimer's disease (AD), but soluble oligomeric Aβ is considered to be more potent and has been hypothesized to directly impair learning and memory. Also, evidences from some clinical studies indicated that Aβ oligomer formation is the major cause for early AD onset. However, the biochemical mechanism involved in the oligomer-induced toxicity is not very well addressed. So, thise present study was undertaken to study the effects of single intracerebroventricular (icv) injection of protofibrillar Aβ 1-42 on the behavioral and biochemical profile in rats. METHODS Rats were divided into two groups (n = 8 per group): (1) sham control group and (2) Aβ 1-42 injected group. A single dose of protofibrillar Aβ 1-42 (5 ul) through icv injection was bilaterally administered into the dorsal hippocampus, while sham control animals were administered with 5 µl of vehicle. RESULTS The results demonstrated that the protofibrillar Aβ significantly inhibited long-term memory retention and increased anxiety levels as shown by the behavioral studies. The amyloid deposits were present inside the brain even six weeks after injection as confirmed by thioflavin-T staining and the neurodegeneration induced by these deposits was confirmed by Nissl's staining in hippocampal and cortical regions. The amyloid aggregates induced reactive oxygen species (ROS) production, acetylcholinesterase activity, nitrite levels, lipid peroxidation, and inhibited antioxidant enzyme activity in hippocampus, cortex, and striatum regions of rat brain after six weeks. DISCUSSION The present study indicated that protofibrillar Aβ 1-42 injection altered long term memory, induced anxiety-like behavior and also developed Alzheimer's disease like pathology in rats.
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Key Words
- AChE, Acetylcholinesterase
- AD, Alzheimer’s disease
- APP, Amyloid precursor protein
- Alzheimer’s disease
- Amyloid beta 1-42
- Anxiety
- Aβ, Amyloid beta
- CA1, Cornus ammonis
- DCFH-DA, 2,7-dichlorofluorescein diacetate
- DMSO, Dimethylsulphoxide
- LPO, lipid peroxidation
- LTP, Long term potentiation
- MDA, Malondialdehyde
- Memory retention
- NFT, neurofibrillary tangle
- Oxidative stress
- ROS, Reactive oxygen species
- SOD, Superoxide dismutase
- TBA, Thiobarbituric acid
- Th-T, Thioflavin-T
- icv, intracerebroventricular
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Affiliation(s)
- Sheetal Sharma
- a Department of Biophysics, Basic Medical Sciences Block II , Panjab University , Chandigarh , India
| | - Sonia Verma
- a Department of Biophysics, Basic Medical Sciences Block II , Panjab University , Chandigarh , India
| | - Monika Kapoor
- a Department of Biophysics, Basic Medical Sciences Block II , Panjab University , Chandigarh , India
| | - Avneet Saini
- a Department of Biophysics, Basic Medical Sciences Block II , Panjab University , Chandigarh , India
| | - Bimla Nehru
- a Department of Biophysics, Basic Medical Sciences Block II , Panjab University , Chandigarh , India
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Rojas JM, Matsen ME, Mundinger TO, Morton GJ, Stefanovski D, Bergman RN, Kaiyala KJ, Taborsky GJ, Schwartz MW. Glucose intolerance induced by blockade of central FGF receptors is linked to an acute stress response. Mol Metab 2015; 4:561-8. [PMID: 26266088 PMCID: PMC4529498 DOI: 10.1016/j.molmet.2015.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 05/22/2015] [Accepted: 05/27/2015] [Indexed: 01/19/2023] Open
Abstract
Objective Central administration of ligands for fibroblast growth factor receptors (FGFRs) such as fibroblast growth factor-19 (FGF19) and FGF21 exert glucose-lowering effects in rodent models of obesity and type 2 diabetes (T2D). Conversely, intracerebroventricular (icv) administration of the non-selective FGFR inhibitor (FGFRi) PD173074 causes glucose intolerance, implying a physiological role for neuronal FGFR signaling in glucose homeostasis. The current studies were undertaken to identify neuroendocrine mechanisms underlying the glucose intolerance induced by pharmacological blockade of central FGFRs. Methods Overnight fasted, lean, male, Long-Evans rats received icv injections of either PD173074 or vehicle (Veh) followed 30 min later by performance of a frequently sampled intravenous glucose tolerance test (FSIGT). Minimal model analysis of glucose and insulin data from the FSIGT was performed to estimate insulin-dependent and insulin-independent components of glucose disposal. Plasma levels of lactate, glucagon, corticosterone, non-esterified free fatty acids (NEFA) and catecholamines were measured before and after intravenous (iv) glucose injection. Results Within 20 min of icv PD173074 injection (prior to the FSIGT), plasma levels of lactate, norepinephrine and epinephrine increased markedly, and each returned to baseline rapidly (within 8 min) following the iv glucose bolus. In contrast, plasma glucagon levels were not altered by icv FGFRi at either time point. Consistent with a previous report, glucose tolerance was impaired following icv PD173074 compared to Veh injection and, based on minimal model analysis of FSIGT data, this effect was attributable to reductions of both insulin secretion and the basal insulin effect (BIE), consistent with the inhibitory effect of catecholamines on pancreatic β-cell secretion. By comparison, there were no changes in glucose effectiveness at zero insulin (GEZI) or the insulin sensitivity index (SI). To determine if iv glucose (given during the FSIGT) contributed to the rapid resolution of the sympathoadrenal response induced by icv FGFRi, we performed an additional study comparing groups that received iv saline or iv glucose 30 min after icv FGFRi. Our finding that elevated plasma catecholamine levels returned rapidly to baseline irrespective of whether rats subsequently received an iv bolus of saline or glucose indicates that the rapid reversal of sympathoadrenal activation following icv FGFRi was unrelated to the subsequent glucose bolus. Conclusions The effect of acute inhibition of central FGFR signaling to impair glucose tolerance likely involves a stress response associated with pronounced, but transient, sympathoadrenal activation and an associated reduction of insulin secretion. Whether this effect is a true consequence of FGFR blockade or involves an off-target effect of the FGFR inhibitor requires additional study. icv FGFR antagonist causes glucose intolerance in rats. This effect is associated with robust sympathoadrenal activation. The sympathoadrenal response is rapid in onset, but clears rapidly. Reduced insulin secretion contributes to FGFR inhibitor-induced glucose intolerance.
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Key Words
- AIRg, acute insulin response to glucose
- AUC, area under the curve
- BIE, basal insulin effect
- CNS, central nervous system
- Central FGF receptors
- DI, disposition index
- FGF receptor inhibitor PD173074
- FGF, fibroblast growth factor
- FGF19, Fibroblast growth factor-19
- FGFR, fibroblast growth factor receptor
- FGFRi, FGFR inhibitor
- FSIGT, frequently sampled intravenous glucose tolerance test
- Frequently sampled intravenous glucose tolerance test
- GE, glucose effectiveness
- GEZI, glucose effectiveness at zero insulin
- Glucose metabolism
- Ibasal, basal insulin
- Kg, glucose disappearance constant
- Minimal model
- NEFA, non-esterified free fatty acids
- SG, glucose effectiveness at basal insulin
- SI, insulin sensitivity
- Sympathoadrenal response
- icv, intracerebroventricular
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Affiliation(s)
- Jennifer M Rojas
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Miles E Matsen
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Thomas O Mundinger
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Gregory J Morton
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Karl J Kaiyala
- Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Gerald J Taborsky
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA ; Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Michael W Schwartz
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
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Rojas JM, Bruinstroop E, Printz RL, Alijagic-Boers A, Foppen E, Turney MK, George L, Beck-Sickinger AG, Kalsbeek A, Niswender KD. Central nervous system neuropeptide Y regulates mediators of hepatic phospholipid remodeling and very low-density lipoprotein triglyceride secretion via sympathetic innervation. Mol Metab 2015; 4:210-21. [PMID: 25737956 PMCID: PMC4338317 DOI: 10.1016/j.molmet.2015.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/29/2014] [Accepted: 01/09/2015] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE Elevated very low-density lipoprotein (VLDL)-triglyceride (TG) secretion from the liver contributes to an atherogenic dyslipidemia that is associated with obesity, diabetes and the metabolic syndrome. Numerous models of obesity and diabetes are characterized by increased central nervous system (CNS) neuropeptide Y (NPY); in fact, a single intracerebroventricular (icv) administration of NPY in lean fasted rats elevates hepatic VLDL-TG secretion and does so, in large part, via signaling through the CNS NPY Y1 receptor. Thus, our overarching hypothesis is that elevated CNS NPY action contributes to dyslipidemia by activating central circuits that modulate liver lipid metabolism. METHODS Chow-fed Zucker fatty (ZF) rats were pair-fed by matching their caloric intake to that of lean controls and effects on body weight, plasma TG, and liver content of TG and phospholipid (PL) were compared to ad-libitum (ad-lib) fed ZF rats. Additionally, lean 4-h fasted rats with intact or disrupted hepatic sympathetic innervation were treated with icv NPY or NPY Y1 receptor agonist to identify novel hepatic mechanisms by which NPY promotes VLDL particle maturation and secretion. RESULTS Manipulation of plasma TG levels in obese ZF rats, through pair-feeding had no effect on liver TG content; however, hepatic PL content was substantially reduced and was tightly correlated with plasma TG levels. Treatment with icv NPY or a selective NPY Y1 receptor agonist in lean fasted rats robustly activated key hepatic regulatory proteins, stearoyl-CoA desaturase-1 (SCD-1), ADP-ribosylation factor-1 (ARF-1), and lipin-1, known to be involved in remodeling liver PL into TG for VLDL maturation and secretion. Lastly, we show that the effects of CNS NPY on key liporegulatory proteins are attenuated by hepatic sympathetic denervation. CONCLUSIONS These data support a model in which CNS NPY modulates mediators of hepatic PL remodeling and VLDL maturation to stimulate VLDL-TG secretion that is dependent on the Y1 receptor and sympathetic signaling to the liver.
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Key Words
- AGPAT, 1-acyl-glycerol-3-phosphate acyltransferase
- ARF-1, ADP-ribosylation factor-1
- ApoB, apolipoprotein B
- CNS, central nervous system
- Cyto, cytoplasmic
- DAG, diacylglycerol
- DGAT, diacylglycerol acyltransferase
- ER, endoplasmic reticulum
- FFA(s), free fatty acid(s)
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- HDAC-1, histone deacetylase-1
- Lipin-1
- NE, norepinephrine
- NPY Y1 receptor
- NPY, neuropeptide Y
- Nuc, nuclear
- PA, phosphatidic acid
- PAP-1, phosphatidic acid phosphatase-1
- PF, pair-fed
- PL, phospholipid
- PLD, phospholipase D
- POMC, proopiomelanocortin
- Phospholipid
- RPL13A, ribosomal protein L13a
- RT-PCR, real-time PCR
- SCD-1, stearoyl-CoA desaturase-1
- SNS, sympathetic nervous system
- Sham, sham-denervation
- Sx, sympathetic denervation
- Sympathetic denervation
- TG, triglyceride
- Triglyceride
- VLDL
- VLDL, very low-density lipoprotein
- Veh, vehicle
- ZF, Zucker fatty
- ad-lib, ad-libitum
- icv, intracerebroventricular
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Affiliation(s)
- Jennifer M. Rojas
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Eveline Bruinstroop
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard L. Printz
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Aldijana Alijagic-Boers
- Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Ewout Foppen
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Maxine K. Turney
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Leena George
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Annette G. Beck-Sickinger
- Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, Leipzig University, Leipzig, Germany
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Kevin D. Niswender
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
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