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Morozko EL, Ochaba J, Hernandez SJ, Lau A, Sanchez I, Orellana I, Kopan L, Crapser J, Duong JH, Overman J, Yeung S, Steffan JS, Reidling J, Thompson LM. Longitudinal Biochemical Assay Analysis of Mutant Huntingtin Exon 1 Protein in R6/2 Mice. J Huntingtons Dis 2019; 7:321-335. [PMID: 30452420 DOI: 10.3233/jhd-180329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 11/15/2022]
Abstract
BACKGROUND Biochemical analysis of mutant huntingtin (mHTT) aggregation species in HD mice is a common measure to track disease. A longitudinal and systematic study of how tissue processing affects detection of conformers has not yet been reported. Understanding the homeostatic flux of mHTT over time and under different processing conditions would aid in interpretation of pre-clinical assessments of disease interventions. OBJECTIVE Provide a systematic evaluation of tissue lysis methods and molecular and biochemical assays in parallel with behavioral readouts in R6/2 mice to establish a baseline for HTT exon1 protein accumulation. METHODS Established biochemical methods were used to process tissue from R6/2 mice of specific ages following behavior tasks. Aggregation states and accumulation of mHTT exon 1 protein were evaluated using multiple break and assay methods to determine potential conformational flux assay specificity in detection of mHTT species, and tissue specificity of conformers. RESULTS Detection of mHTT exon 1 protein species varied based on biochemical processing and analysis providing a baseline for subsequent studies in R6/2 mice. Insoluble, high molecular weight species of mHTT exon 1 protein increased and tracked with onset of behavioral impairments in R6/2 mice using multiple assay methods. CONCLUSIONS Conformational flux from soluble monomer to high molecular weight, insoluble species of mHTT exon 1 protein was generally consistent for multiple assay methods throughout R6/2 disease progression; however, the results support the use of multiple biochemical techniques to detect mHTT exon 1 protein species for preclinical assessments in HD mouse models expressing mHTT exon 1 protein.
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Affiliation(s)
- Eva L Morozko
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Joseph Ochaba
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA.,University of California, Irvine, Psychiatry & Human Behavior, Irvine, CA, USA
| | - Sarah J Hernandez
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Alice Lau
- University of California, Irvine, Psychiatry & Human Behavior, Irvine, CA, USA
| | - Isabella Sanchez
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Iliana Orellana
- Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA
| | - Lexi Kopan
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Joshua Crapser
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Janet H Duong
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Julia Overman
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA
| | - Silvia Yeung
- Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA
| | - Joan S Steffan
- University of California, Irvine, Psychiatry & Human Behavior, Irvine, CA, USA.,Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA
| | - Jack Reidling
- Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA
| | - Leslie M Thompson
- University of California, Irvine, Neurobiology and Behavior, Irvine, CA, USA.,University of California, Irvine, Psychiatry & Human Behavior, Irvine, CA, USA.,Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA
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Abstract
STATEMENT OF THE PROBLEM Dual-cured cements have been used with castable ceramic restorations, but the tensile bond strengths of these materials have not been thoroughly researched. PURPOSE OF THE STUDY This study compared the tensile bond strengths between Dicor castable ceramics and enamel of four dual-cure cements: Twinlook, Optec Dual-Cure Luting Cement, Clearfil CR Inlay, and Dual Cement. MATERIAL AND METHODS Truncated cones made of Dicor castable ceramics were cemented to enamel of freshly extracted anterior teeth with these four cements. Before testing, all specimens were immersed in water at 37 degrees C for 24 hours, and thermocycled 1000 times in 5 degrees C and 55 degrees C water, with a dwell time of 30 seconds each. Tensile force was used to separate each specimen with the Instron universal testing machine. RESULTS Clearfil CR Inlay cement exhibited the highest mean tensile bond strength (18.4 MPa), followed by Dual (18.3 MPa), Twinlook (15.2 MPa), and Optec Dual-Cure luting (14.9 MPa) cements. One-way analysis of variance did not reveal any significant differences (p = 0.05) among groups. A majority of the fracture was adhesive at the ceramic and cement interface. CONCLUSION All four dual-cured cements formed strong bonds between enamel and Dicor cement, ranging from 14.90 MPa to 18.35 MPa, and there was no statistically significant difference.
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Affiliation(s)
- J C Chang
- Department of Prosthodontics, University of Texas Dental Branch, Houston 77030, USA
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