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Phetsanthad A, Vu NQ, Yu Q, Buchberger AR, Chen Z, Keller C, Li L. Recent advances in mass spectrometry analysis of neuropeptides. MASS SPECTROMETRY REVIEWS 2023; 42:706-750. [PMID: 34558119 PMCID: PMC9067165 DOI: 10.1002/mas.21734] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/22/2021] [Accepted: 08/28/2021] [Indexed: 05/08/2023]
Abstract
Due to their involvement in numerous biochemical pathways, neuropeptides have been the focus of many recent research studies. Unfortunately, classic analytical methods, such as western blots and enzyme-linked immunosorbent assays, are extremely limited in terms of global investigations, leading researchers to search for more advanced techniques capable of probing the entire neuropeptidome of an organism. With recent technological advances, mass spectrometry (MS) has provided methodology to gain global knowledge of a neuropeptidome on a spatial, temporal, and quantitative level. This review will cover key considerations for the analysis of neuropeptides by MS, including sample preparation strategies, instrumental advances for identification, structural characterization, and imaging; insightful functional studies; and newly developed absolute and relative quantitation strategies. While many discoveries have been made with MS, the methodology is still in its infancy. Many of the current challenges and areas that need development will also be highlighted in this review.
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Affiliation(s)
- Ashley Phetsanthad
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Nhu Q. Vu
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Qing Yu
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705, USA
| | - Amanda R. Buchberger
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Zhengwei Chen
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Caitlin Keller
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705, USA
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D-Alanine in the islets of Langerhans of rat pancreas. Biochem Biophys Res Commun 2014; 447:328-33. [PMID: 24721429 DOI: 10.1016/j.bbrc.2014.03.153] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 03/31/2014] [Indexed: 11/24/2022]
Abstract
Relatively high levels of D-alanine (D-Ala), an endogenous D-amino acid, have been found in the endocrine systems of several animals, especially in the anterior pituitary; however, its functional importance remains largely unknown. We observed D-Ala in islets of Langerhans isolated from rat pancreas in significantly higher levels than in the anterior/intermediate pituitary; specifically, 180±60 fmol D-Ala per islet (300±100 nmol/gislet), and 10±2.5 nmol/g of wet tissue in pituitary. Additionally, 12±5% of the free Ala in the islets was in the d form, almost an order of magnitude higher than the percentage of D-Ala found in the pituitary. Surprisingly, glucose stimulation of the islets resulted in D-Ala release of 0.6±0.5 fmol per islet. As D-Ala is stored in islets and released in response to changes in extracellular glucose, D-Ala may have a hormonal role.
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Romanova EV, Aerts JT, Croushore CA, Sweedler JV. Small-volume analysis of cell-cell signaling molecules in the brain. Neuropsychopharmacology 2014; 39:50-64. [PMID: 23748227 PMCID: PMC3857641 DOI: 10.1038/npp.2013.145] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 04/26/2013] [Accepted: 05/06/2013] [Indexed: 12/19/2022]
Abstract
Modern science is characterized by integration and synergy between research fields. Accordingly, as technological advances allow new and more ambitious quests in scientific inquiry, numerous analytical and engineering techniques have become useful tools in biological research. The focus of this review is on cutting edge technologies that aid direct measurement of bioactive compounds in the nervous system to facilitate fundamental research, diagnostics, and drug discovery. We discuss challenges associated with measurement of cell-to-cell signaling molecules in the nervous system, and advocate for a decrease of sample volumes to the nanoliter volume regimen for improved analysis outcomes. We highlight effective approaches for the collection, separation, and detection of such small-volume samples, present strategies for targeted and discovery-oriented research, and describe the required technology advances that will empower future translational science.
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Affiliation(s)
- Elena V Romanova
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jordan T Aerts
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Callie A Croushore
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jonathan V Sweedler
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Romanova EV, Lee JE, Kelleher NL, Sweedler JV, Gulley JM. Comparative peptidomics analysis of neural adaptations in rats repeatedly exposed to amphetamine. J Neurochem 2012; 123:276-87. [PMID: 22860605 PMCID: PMC3463764 DOI: 10.1111/j.1471-4159.2012.07912.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/02/2012] [Accepted: 08/03/2012] [Indexed: 01/29/2023]
Abstract
Repeated exposure to amphetamine (AMPH) induces long-lasting behavioral changes, referred to as sensitization, that are accompanied by various neuroadaptations in the brain. To investigate the chemical changes that occur during behavioral sensitization, we applied a comparative proteomics approach to screen for neuropeptide changes in a rodent model of AMPH-induced sensitization. By measuring peptide profiles with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and comparing signal intensities using principal component analysis and variance statistics, subsets of peptides are found with significant differences in the dorsal striatum, nucleus accumbens, and medial prefrontal cortex of AMPH-sensitized male Sprague-Dawley rats. These biomarker peptides, identified in follow-up analyses using liquid chromatography and tandem mass spectrometry, suggest that behavioral sensitization to AMPH is associated with complex chemical adaptations that regulate energy/metabolism, neurotransmission, apoptosis, neuroprotection, and neuritogenesis, as well as cytoskeleton integrity and neuronal morphology. Our data contribute to a growing number of reports showing that in addition to the mesolimbic dopamine system, which is the best known signaling pathway involved with reinforcing the effect of psychostimulants, concomitant chemical changes in other pathways and in neuronal organization may play a part in the overall effect of chronic AMPH exposure on behavior.
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Affiliation(s)
- Elena V. Romanova
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801, USA
| | - Ji Eun Lee
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801, USA
| | - Neil L. Kelleher
- Department of Chemistry, Department of Molecular Biosciences, and The Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Rd., Evanston, IL USA
| | - Jonathan V. Sweedler
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Joshua M. Gulley
- Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel St., Champaign, IL 61820, USA
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Romanova EV, Lee JE, Kelleher NL, Sweedler JV, Gulley JM. Mass spectrometry screening reveals peptides modulated differentially in the medial prefrontal cortex of rats with disparate initial sensitivity to cocaine. AAPS JOURNAL 2010; 12:443-54. [PMID: 20490734 DOI: 10.1208/s12248-010-9204-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 05/03/2010] [Indexed: 01/06/2023]
Abstract
To better understand why certain individuals are more vulnerable to cocaine abuse and addiction, we identify peptide markers associated with individual variation in sensitivity to the behavioral effects of cocaine. Previous studies in rats show that low, compared to high, cocaine responders are more sensitive to cocaine-induced behavioral plasticity (sensitization), exhibit enhanced conditioning to cocaine's rewarding effects, and are more motivated to self administer cocaine. In the current study, we combine matrix-assisted laser desorption/ionization mass spectrometry with multivariate statistical methods to analyze tissue extracts from rat dorsal striatum, nucleus accumbens, and medial prefrontal cortex (mPFC) to examine trends in peptide changes that coincide with behavioral phenotype. Peptide profiles of these three regions from individual animals were characterized via mass spectrometry. Resulting mass peaks that were statistically different between these groups were identified using principal component analysis. The mass peaks were then identified in pooled samples via multistage liquid chromatography mass spectrometry. A total of 74 peptides from 28 proteins were sequenced from defined brain regions. Statistically significant changes in peak intensities for seven peptides were found in the mPFC of rats given a single injection of 10 mg/kg cocaine, with low cocaine responders showing approximately 2-fold increase in peak intensities for the acetylated N terminus peptides of stathmin and Hint 1, as well as truncated ATP synthase. These results suggest that distinct peptide profiles in the mPFC are associated with individuals that exhibit reduced sensitivity to the behavioral effects of cocaine.
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Affiliation(s)
- Elena V Romanova
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, Illinois 61801, USA
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Zimmerman TA, Rubakhin SS, Romanova EV, Tucker KR, Sweedler JV. MALDI mass spectrometric imaging using the stretched sample method to reveal neuropeptide distributions in aplysia nervous tissue. Anal Chem 2009; 81:9402-9. [PMID: 19835365 PMCID: PMC2837479 DOI: 10.1021/ac901820v] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuropeptides are a diverse set of complex cell-cell signaling molecules that modulate behavior, learning, and memory. Their spatially heterogeneous distributions, large number of post-translational modifications, and wide range of physiologically active concentrations make their characterization challenging. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging is well-suited to characterizing and mapping neuropeptides in the central nervous system. Because matrix application can cause peptide migration within tissue samples, application parameters for MALDI typically represent a compromise between attaining the highest signal quality and preserving native spatial distributions. The stretched sample approach minimizes this trade-off by fragmenting the tissue section into thousands of spatially isolated islands, each approximately 40 mum in size. This inhibits analyte migration between the pieces and, at the same time, reduces analyte-salt adduct formation. Here, we present methodological improvements that enable the imaging of stretched tissues and reveal neuropeptide distributions in nervous tissue from Aplysia californica. The distributions of known neuropeptides are shown to correspond with previous immunohistochemical results, demonstrating that the stretched imaging method is well-suited for working with easily redistributed molecules and heterogeneous tissues and reduces adducts from physiological salts.
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Affiliation(s)
- Tyler A. Zimmerman
- Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801
| | - Stanislav S. Rubakhin
- Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801
| | - Elena V. Romanova
- Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801
| | - Kevin R. Tucker
- Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801
| | - Jonathan V. Sweedler
- Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801
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