Label-free quantitative proteomics analysis for type 2 diabetes mellitus early diagnostic marker discovery using data-independent acquisition mass spectrometry (DIA-MS)

Type-2 diabetes mellitus (T2DM) therapy requires early diagnosis and complication avoidance. Unfortunately, current diagnostic markers do not meet these needs. Data-independent acquisition mass spectrometry (DIA-MS) offers a solution for clinical diagnosis, providing reliable and precise sample quantification. This study utilized DIA-MS to investigate proteomic differential expression in the serum of recently diagnosed T2DM patients. The study conducted a comparative protein expression analysis between healthy and recently diagnosed T2DM groups (discovery cohort). A candidate protein was then validated using enzyme-linked immune assay (ELISA) on serum samples collected from T2DM patients (n = 87) and healthy control (n = 60) (validation cohort). A total of 1074 proteins were identified, and 90 were significantly dysregulated between the two groups, including 32 newly associated with T2DM. Among these proteins, the expression of S100 calcium-binding protein A6 (S100A6) was validated by ELISA. It showed a significant increase in T2DM samples compared to the control group. It was evaluated as a biomarker using the receiver operating characteristic (ROC) curve, consistent with the DIA-MS results. Novel proteins are reported to be involved in the development and progression of T2DM. Further studies are required to investigate the differential expression of candidate marker proteins in a larger population of T2DM patients.

TMT-based quantitative proteomic analysis of cumulus cells derived from vitrified porcine immature oocytes following in vitro maturation

As the immature oocytes are submitted to cryopreservation, their surrounding cumulus cells (CCs) will inevitably suffer, which may have some adverse effects on subsequent oocyte maturation and development. So far, little is known about the molecular differences in CCs of immature oocytes after vitrification. The aim of this study therefore was to analyze the protein profile of CCs derived from vitrified porcine immature oocytes following in vitro maturation, using TMT-based quantitative proteomic approach. A total of 5910 proteins were identified, and 88 of them presented significant difference, with 46 up-regulated and 42 down-regulated proteins. Gene Ontology enrichment analysis revealed that cell cycle phase transition, mitotic cell cycle phase transition, positive regulation of cell differentiation and regulation of oogenesis were significantly down-regulated within the biological process. After Kyoto Encyclopedia of Genes and Genomes pathway analysis, some up-regulated proteins were significantly enriched in TGF-beta signaling pathway and 4 pathways related to steroid hormones. Furthermore, 10 selected proteins were quantified and verified by a parallel reaction monitoring technique, indicating a high reliability of the TMT results. In conclusion, vitrification affects protein profile of CCs as well as their biological functions, which will offer a new perspective to understand the reasons for decline in maturation quality of vitrified immature oocytes.