Label-Free Quantitation of Endogenous Peptides.

Liquid chromatography-mass spectrometry (LC-MS)-based peptidomics methods allow for the detection and identification of many peptides in a complex biological mixture in an untargeted manner. Quantitative peptidomics approaches allow for comparisons of peptide abundance between different samples, allowing one to draw conclusions about peptide differences as a function of experimental treatment or physiology. While stable isotope labeling is a powerful approach for quantitative proteomics and peptidomics, advances in mass spectrometry instrumentation and analysis tools have allowed label-free methods to gain popularity in recent years.

Proteomic Identification of Seasonally Expressed Proteins Contributing to Heart Function and the Avoidance of Skeletal Muscle Disuse Atrophy in a Hibernating Mammal.

Hibernation in the thirteen-lined ground squirrel () takes place over 4-6 months and is characterized by multiday bouts of hypothermic torpor (5-7 °C core body temperature) that are regularly interrupted every 1-2 weeks by brief (12-24 h) normothermic active periods called interbout arousals. Our goal was to gain insight into the molecular mechanisms that underlie the hibernator's ability to preserve heart function and avoid the deleterious effects of skeletal muscle disuse atrophy over prolonged periods of inactivity, starvation, and near-freezing body temperatures. To achieve this goal, we performed organelle enrichment of heart and skeletal muscle at five seasonal time points followed by LC-MS-based label-free quantitative proteomics.

Effects of Anesthetic Administration on Rat Hypothalamus and Cerebral Cortex Peptidome.

Prohormone-derived neuropeptides act as cell-cell signaling molecules to mediate a wide variety of biological processes in the animal brain. Mass spectrometry-based peptidomic experiments are valuable approaches to gain insight into the dynamics of individual peptides under different physiological conditions or experimental treatments. However, the use of anesthetics during animal procedures may confound experimental peptide measurements, especially in the brain, where anesthetics act.

Short-Term Administration of Common Anesthetics Does Not Dramatically Change the Endogenous Peptide Profile in the Rat Pituitary.

Cell-cell signaling peptides (e.g., peptide hormones, neuropeptides) are among the largest class of cellular transmitters and regulate a variety of physiological processes.

Peptidomics analysis reveals changes in small urinary peptides in patients with interstitial cystitis/bladder pain syndrome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic and debilitating pain disorder of the bladder and urinary tract with poorly understood etiology. A definitive diagnosis of IC/BPS can be challenging because many symptoms are shared with other urological disorders. An analysis of urine presents an attractive and non-invasive resource for monitoring and diagnosing IC/BPS.

Identifying Receptors for Neuropeptides and Peptide Hormones: Challenges and Recent Progress.

Intercellular signaling events mediated by neuropeptides and peptide hormones represent important targets for both basic science and drug discovery. For many bioactive peptides, the protein receptors that transmit information across the receiving cell membrane are not known, severely limiting these signaling pathways as potential therapeutic targets. Identifying the receptor(s) for a given peptide of interest is complicated by several factors.