In the effort to understand brain function in both healthy and disease states, it is important to identify the active structures of cell-to-cell signaling neuropeptides and elucidate their cellular signaling pathways. This information enables the design of therapeutic compounds to modulate these pathways for treating a variety of human health conditions. Neuropeptides can undergo a subtle post-translational modification (PTM) that isomerizes one amino acid residue from the L-stereoisomer to the D-stereoisomer. L- to D-residue isomerization alters the three-dimensional structure of the resulting D-amino acid-containing peptide (DAACP), often leading to significantly higher biological potency and stability relative to the all-L-residue analogue. A related PTM is the formation of isoaspartate from aspartate residues to form isoaspartate-containing peptides (IsoAspPs), a modification that has been implicated in a number of neurological disorders. However, both L- to D-residue isomerization and isoaspartate formation are difficult to detect because these modifications do not change a compound?s mass or chemical composition, rendering these PTMs ?invisible? to most peptide characterization approaches. The central hypothesis is that DAACPs and IsoAspPs are present as cell-to-cell signaling peptides in many animals, including mammals, but have been mischaracterized due to technological deficiencies in detecting peptide residue isomerization. There is currently an unmet requirement for methods to detect and predict the occurrence of these functionally important PTMs. This need is addressed with a DAACP and IsoAspP discovery funnel, a new technology designed to study the synthesis and signaling of peptides that undergo isomerization, with the long-term objective being to use this information to establish the neurobiological role these PTMs play in healthy organisms and in neurological disorders.
Aim 1 will develop a non-targeted method to screen for DAACPs and IsoAspPs in a variety of animals and biological tissues. The method will be used to fully characterize the suite of DAACPs and IsoAspPs present in the central nervous system of the model organism Aplysia californica, as well as in central nervous, endocrine, and heart tissues of mouse. Simultaneously, Aim 2 will create a method to identify DAACPs and IsoAspPs at the level of the single cell using on-slide enzymatic digestion coupled to sensitive single cell mass spectrometry techniques. Finally, Aim 3 will fully characterize the biosynthesis and signaling of known DAACPs in Aplysia, including identifying the first L/D-isomerase enzyme that acts on cell-to-cell signaling peptides, which will allow for the identification of homologous enzymes in other animals, including mammals. Together, these efforts will define the importance of cell-to-cell signaling DAACPs and IsoAspPs and characterize their synthesis and function throughout the nervous system. The tools developed will have wide applicability to many future investigations of cell-to-cell signaling molecules.

Public Health Relevance

Many neurological diseases are caused by an improper regulation of cell-to-cell signaling molecules, and fully characterizing these signaling molecules and their functions is important to understanding cellular communication in both normal and diseased states. A suite of analytical approaches are being developed to detect and fully characterize peptide signaling molecules that contain two subtle but biologically important modifications, L- to D-residue isomerization and isoaspartate formation. Fully understanding the role of these modifications in neurobiology will provide new insights into brain function, and reveal new diagnostic and therapeutic targets.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS031609-23A1
Application #
9538462
Study Section
Enabling Bioanalytical and Imaging Technologies Study Section (EBIT)
Program Officer
Talley, Edmund M
Project Start
1993-05-01
Project End
2023-03-31
Budget Start
2018-04-01
Budget End
2019-03-31
Support Year
23
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Tai, Hua-Chia; Checco, James W; Sweedler, Jonathan V (2018) Non-targeted Identification of D-Amino Acid-Containing Peptides Through Enzymatic Screening, Chiral Amino Acid Analysis, and LC-MS. Methods Mol Biol 1719:107-118
Yang, Ning; Anapindi, Krishna D B; Rubakhin, Stanislav S et al. (2018) Neuropeptidomics of the Rat Habenular Nuclei. J Proteome Res 17:1463-1473
Anapindi, Krishna D B; Romanova, Elena V; Southey, Bruce R et al. (2018) Peptide identifications and false discovery rates using different mass spectrometry platforms. Talanta 182:456-463
Zhang, Guo; Yuan, Wang-Ding; Vilim, Ferdinand S et al. (2018) Newly Identified Aplysia SPTR-Gene Family-Derived Peptides: Localization and Function. ACS Chem Neurosci 9:2041-2053
Checco, James W; Zhang, Guo; Yuan, Wang-Ding et al. (2018) Aplysia allatotropin-related peptide and its newly identified d-amino acid-containing epimer both activate a receptor and a neuronal target. J Biol Chem 293:16862-16873
Monroe, Eric B; Annangudi, Suresh P; Wadhams, Andinet A et al. (2018) Exploring the Sea Urchin Neuropeptide Landscape by Mass Spectrometry. J Am Soc Mass Spectrom 29:923-934
Checco, James W; Zhang, Guo; Yuan, Wang-Ding et al. (2018) Molecular and Physiological Characterization of a Receptor for d-Amino Acid-Containing Neuropeptides. ACS Chem Biol 13:1343-1352
Do, Thanh D; Checco, James W; Tro, Michael et al. (2018) Conformational investigation of the structure-activity relationship of GdFFD and its analogues on an achatin-like neuropeptide receptor of Aplysia californica involved in the feeding circuit. Phys Chem Chem Phys 20:22047-22057
Yang, Ning; Anapindi, Krishna D B; Romanova, Elena V et al. (2017) Improved identification and quantitation of mature endogenous peptides in the rodent hypothalamus using a rapid conductive sample heating system. Analyst 142:4476-4485
Zhang, Guo; Vilim, Ferdinand S; Liu, Dan-Dan et al. (2017) Discovery of leucokinin-like neuropeptides that modulate a specific parameter of feeding motor programs in the molluscan model, Aplysia. J Biol Chem 292:18775-18789

Showing the most recent 10 out of 68 publications