Evroula Hapeshi ^1* Victoria Samanidou ² Yiannis Sarigiannis ¹ CHRISTOS PETROU ¹ Panagiotis Vorkas ³

• ¹ University of Nicosia, Nicosia, Cyprus
• ² Aristotle University of Thessaloniki, Thessaloniki, Greece
• ³ Imperial College London, London, United Kingdom

necessitating their inclusion in combined BFI panels. Further research is needed to determine the 54 sources of these metabolites in urine after protein-rich meals (La Barbera et al., 2024). 55Most applied proteomics studies are conducted with heterogeneous cell populations, leading to 56 a loss of protein content information specific to individual cells. Analyzing cells individually can 57 eliminate this dilution effect, but single-cell proteomic analysis is challenging due to the low protein 58 levels available for sample preparation and mass spectrometric analysis. A robust, Thermal inkjet 59 (TIJ)-enabled, label-free single-cell proteomic workflow has been introduced, which is accessible to 60 the research community due to its affordability and reliance on commonly available components 61 (Stanisheuski et al., 2024). This method has successfully achieved the label-free identification of up to 62 1,300 proteins from a single cell in a single run. The protocol's development and applicability for 63 proteomics of single cells from various cell lines, mixed cell suspensions, and glioblastoma tumor 64 spheroids have been demonstrated. This cost-effective and reliable single-cell proteomics workflow 65 can be adopted by other laboratories interested in studying cells at the individual level (Stanisheuski et 66 al., 2024). 67In recent years, peptidomic strategies have been used to study modifications of antimicrobial 68 peptides (AMPs) to enhance their activity. N-capping and C-capping, involving specific amino acids 69 or unconventional motifs, can alter peptide secondary structure and improve activity against 70 pharmacological targets. These capping motifs help prevent peptide degradation and optimize peptide 71 variants. Brango-Vanegas et al. ( 2024) discuss strategies for creating N-and C-cap motifs to refine 72 AMPs. Understanding these effects could allow customization of AMPs for specific infections or drug 73 delivery, addressing the need for new anti-infectives amid rising antimicrobial resistance. Capping 74 motifs are promising for developing next-generation AMP therapeutics with better efficacy and safety 75 (Brango-Vanegas et al., 2024). 76Recently, the scientific community has focused on applying peptidomics, proteomics, and 77 metabolomics in clinical contexts, such as discovering disease biomarkers and developing drugs. The 78 carcinogenic effects of environmental chemicals are linked to their metabolic activation and DNA 79 damage. In breast cancer, the potency of these compounds is influenced by their composition and the 80 overexpression of AhR and SULT1A1 proteins, with SULT1A1 as a potential biomarker for targeted 81 therapy. Baker et al. (2024) explored the role of the Aryl hydrocarbon Receptor (AhR) in breast cancer 82 and the development of therapeutic molecules. The study showed that CYP1 metabolism occurs at the 83 phenyl head group, with certain substituents reducing cytotoxicity. Further research examined the 84 selectivity and activation of the AhR/CYP1/SULT1A1 axis in breast cancer using cell line models 85 (Baker et al., 2024). 86The results clearly indicate that applying peptidomics, proteomics, and metabolomics in clinical 87 and food science is essential for evaluating and understanding proteins, peptides, and metabolites in 88 clinical samples and food digestion, as well as their impact on human health. In the future, more 89 selective and sensitive strategies in peptidomics, proteomics, and metabolomics will be developed and 90 applied for discovering disease biomarkers, drug development, and identifying novel therapeutic 91 targets. Additionally, these strategies will be used in food research to identify bioactive peptides and 92 biomarkers related to food digestion. 93