Mass Spectrometry-Based Precise Identification of Citrullinated Histones via Limited Digestion and Biotin Derivative Tag Enrichment.

Histone citrullination is an essential epigenetic post-translational modification (PTM) that affects many important physiological and pathological processes, but effective tools to study histone citrullination are greatly limited due to several challenges, including the small mass shift caused by this PTM and its low abundance in biological systems. Although previous studies have reported frequent occurrences of histone citrullination, these methods failed to provide a high-throughput and site-specific strategy to detect histone citrullination. Recently, we developed a biotin thiol tag that enabled precise identification of protein citrullination coupled with mass spectrometry.

Targeted degradation of MERTK and other TAM receptor paralogs by heterobifunctional targeted protein degraders.

TAM receptors (TYRO3, AXL, and MERTK) comprise a family of homologous receptor tyrosine kinases (RTK) that are expressed across a range of liquid and solid tumors where they contribute to both oncogenic signaling to promote tumor proliferation and survival, as well as expressed on myeloid and immune cells where they function to suppress host anti-tumor immunity. In recent years, several strategies have been employed to inhibit TAM kinases, most notably small molecule tyrosine kinase inhibitors and inhibitory neutralizing monoclonal antibodies (mAbs) that block receptor dimerization. Targeted protein degraders (TPD) use the ubiquitin proteasome pathway to redirect E3 ubiquitin ligase activity and target specific proteins for degradation.

Enabling Global Analysis of Protein Citrullination via Biotin Thiol Tag-Assisted Mass Spectrometry.

Citrullination is a key post-translational modification (PTM) that affects protein structures and functions. Although it has been linked to various biological processes and disease pathogenesis, the underlying mechanism remains poorly understood due to a lack of effective tools to enrich, detect, and localize this PTM. Herein, we report the design and development of a biotin thiol tag that enables derivatization, enrichment, and confident identification of citrullination via mass spectrometry.

High-resolution magnetic resonance and mass spectrometry imaging of the human larynx.

High-resolution, noninvasive and nondestructive imaging of the subepithelial structures of the larynx would enhance microanatomic tissue assessment and clinical decision making; similarly, in situ molecular profiling of laryngeal tissue would enhance biomarker discovery and pathology readout. Towards these goals, we assessed the capabilities of high-resolution magnetic resonance imaging (MRI) and matrix-assisted laser desorption/ionisation-mass spectrometry (MALDI-MS) imaging of rarely reported paediatric and adult cadaveric larynges that contained pathologies. The donors were a 13-month-old male, a 10-year-old female with an infraglottic mucus retention cyst and a 74-year-old female with advanced polypoid degeneration and a mucus retention cyst.

Proteome-wide and matrisome-specific alterations during human pancreas development and maturation.

The extracellular matrix (ECM) is unique to each tissue and capable of guiding cell differentiation, migration, morphology, and function. The ECM proteome of different developmental stages has not been systematically studied in the human pancreas. In this study, we apply mass spectrometry-based quantitative proteomics strategies using N,N-dimethyl leucine isobaric tags to delineate proteome-wide and ECM-specific alterations in four age groups: fetal (18-20 weeks gestation), juvenile (5-16 years old), young adults (21-29 years old) and older adults (50-61 years old).

Integrated Label-Free and 10-Plex DiLeu Isobaric Tag Quantitative Methods for Profiling Changes in the Mouse Hypothalamic Neuropeptidome and Proteome: Assessment of the Impact of the Gut Microbiome.

Gut microbiota can regulate host physiological and pathological status through gut-brain communications or pathways. However, the impact of the gut microbiome on neuropeptides and proteins involved in regulating brain functions and behaviors is still not clearly understood. To address the problem, integrated label-free and 10-plex DiLeu isobaric tag-based quantitative methods were implemented to compare the profiling of neuropeptides and proteins in the hypothalamus of germ-free (GF)- vs conventionally raised (ConvR)-mice.

On-Tissue Derivatization with Girard's Reagent P Enhances N-Glycan Signals for Formalin-Fixed Paraffin-Embedded Tissue Sections in MALDI Mass Spectrometry Imaging.

Glycosylation is a major protein post-translational modification whose dysregulation has been associated with many diseases. Herein, an on-tissue chemical derivatization strategy based on positively charged hydrazine reagent (Girard's reagent P) coupled with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was developed for analysis of N-glycans from FFPE treated tissue sections. The performance of the proposed approach was evaluated by analysis of monosaccharides, oligosaccharides, N-glycans released from glycoproteins, as well as MS imaging of N-glycans from human cancer tissue sections.

Subresidue-Resolution Footprinting of Ligand-Protein Interactions by Carbene Chemistry and Ion Mobility-Mass Spectrometry.

The knowledge of ligand-protein interactions is essential for understanding fundamental biological processes and for the rational design of drugs that target such processes. Carbene footprinting efficiently labels proteinaceous residues and has been used with mass spectrometry (MS) to map ligand-protein interactions. Nevertheless, previous footprinting studies are typically performed at the residue level, and therefore, the resolution may not be high enough to couple with conventional crystallography techniques.

Mass Spectrometry Imaging of N-Glycans from Formalin-Fixed Paraffin-Embedded Tissue Sections Using a Novel Subatmospheric Pressure Ionization Source.

N-linked glycosylation, featuring various glycoforms, is one of the most common and complex protein post-translational modifications (PTMs) controlling protein structures and biological functions. It has been revealed that abnormal changes of protein N-glycosylation patterns are associated with many diseases. Hence, unraveling the disease-related alteration of glycosylation, especially the glycoforms, is crucial and beneficial to improving our understanding about the pathogenic mechanisms of various diseases.

Comprehensive urinary metabolomic characterization of a genetically induced mouse model of prostatic inflammation.

Dysfunction of the lower urinary tract commonly afflicts the middle-aged and aging male population. The etiology of lower urinary tract symptoms (LUTS) is multifactorial. Benign prostate hyperplasia, fibrosis, smooth muscle contractility, and inflammation likely contribute.

Mass Spectrometric Imaging Reveals Temporal and Spatial Dynamics of Bioactive Lipids in Arteries Undergoing Restenosis.

Restenosis, or renarrowing of the arterial lumen, is a common recurrent disease following balloon angioplasty and stenting treatments for cardiovascular disease. A major technical barrier for deciphering restenotic mechanisms is the dynamic, spatial profiling of bioactive lipids in the arterial wall, especially in small animals. Here, applying matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI), we conducted the first lipidomic study of temporal-spatial profiling in a small animal model of angioplasty-induced restenosis.

Razor-printed sticker microdevices for cell-based applications.

Tape-based razor-printing is a flexible and affordable ultra-rapid prototyping approach for microscale device fabrication. However, integration of this prototyping approach into cell-based assay development has been limited to proof of principle demonstrations. This is in large part due to lack of an established or well-characterized option for biocompatible adhesive tape.

Restenosis Inhibition and Re-differentiation of TGFβ/Smad3-activated Smooth Muscle Cells by Resveratrol.

To date, there is no periadventitial drug delivery method available in the clinic to prevent restenotic failure of open vascular reconstructions. Resveratrol is a promising anti-restenotic natural drug but subject to low bioavailability when systemically administered. In order to reconcile these two prominent issues, we tested effects of periadventitial delivery of resveratrol on all three major pro-restenotic pathologies including intimal hyperplasia (IH), endothelium impairment, and vessel shrinkage.

Comparative analysis of three Callicarpa herbs using high performance liquid chromatography with diode array detector and electrospray ionization-trap mass spectrometry method.

Three Callicarpa species, namely Callicarpa nudiflora Hook. et Arn., Callicarpa macrophylla Vahl.