Background/Objectives: Endometrial cancer (EC) is the second most frequent gynecological malignant tumor in postmenopausal women. Pathogenic mechanisms related to the onset and development of the disease are still unknown. To identify dysregulated proteins associated with EC we exploited a combined in vitro/in silico approach analyzing the proteome of exosomes with advanced MS techniques and annotating their results by using Chymeris1 AI tools. Methods: To this aim in this pilot study, we performed a deep proteomics analysis with high resolution MS (HRMS), advanced computational tools and western blotting for proteomics data validation. Results: That allowed us to identify 3628 proteins in serum albumin-depleted exosomes from 10 patients with EC compared to 10 healthy controls. This is the largest number of proteins identified in EC serum EVs. After quantification and statistical analysis, we identified 373 significantly (p < 0.05) dysregulated proteins involved in neutrophil and platelet degranulation pathways. A more detailed bioinformatics analysis revealed 61 dysregulated enzymes related to metabolic and catabolic pathways linked to tumor invasion. Through this analysis, we identified 49 metabolic and catabolic pathways related to tumor growth. Conclusions: Altogether, data shed light on the metabolic pathways involved in tumors. This is very important for understanding the metabolism of EC and for the development of new therapies.

Tonsils are secondary lymphoid organs that play a crucial role in the immunological response, with B cells being a major component involved in both innate and adaptive immunity. Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome and obstructive sleep apnea syndrome (OSAS) are both common pediatric conditions involving tonsillar pathology. In both syndromes, the molecular pathways dysregulated in tonsillar B cells are still to be understood. The study aimed to unravel and compare the proteomic profiles of tonsillar CD19+ B cells isolated from pediatric patients with PFAPA (n = 6) and OSAS (n = 6) to identify disease-specific molecular signatures. B cells were isolated from the tonsillar tissue using magnetic microbeads (with a purity of 93.50%). Proteomic analysis was performed by nanoLC-MS/MS with both data-dependent (DDA) and data-independent acquisition (DIA) methods, followed by comprehensive bioinformatic analysis. By merging DDA and DIA datasets, a total of 18.078 unique proteins were identified. Differential expression analysis revealed 83 proteins increased and 49 proteins decreased in OSAS B cells compared to PFAPA B cells (fold change ≥ 1.5 or ≤0.6, p < 0.05). Distinct pathway enrichments were highlighted, including alterations in the regulation of PTEN gene transcription, circadian gene expression, inflammasome pathways (IPAF and AIM2), and the metabolism of angiotensinogen to angiotensin. Specific proteins such as p53, Hdac3, RPTOR, MED1, Caspase-1, Cathepsin D, Chymase, and TLR2 (validated by WB) were shown to be differentially expressed. These findings reveal distinct proteomic signatures in tonsillar B cells from patients with PFAPA and OSAS, offering novel insights into the pathophysiology and potential avenues for biomarker discovery.

Endometrial cancers (ECs) are mainly adenocarcinomas arising from the uterine endometrium. In this work, we employed data-independent acquisition (DIA) mass spectrometry (MS)-based label-free quantification (LFQ-MS) proteomics to analyze the proteome of tissue washings collected from 25 control (CTRL) subjects, 25 patients with low-grade type 1 endometrial cancer (EC), and 24 patients with high-grade type 1 EC. Following quantification and statistical analysis, we identified 42 proteins able to discriminate CTRL from EC patients, and 151 proteins differentiating high-grade EC cases from low-grade EC cases. Notably, PRRC2A and SYDE2 effectively distinguished both EC patients from controls and advanced EC cases from low-grade EC cases. Validation by Western blot analysis in an independent cohort comprising 19 CTRL patients, 19 patients with low-grade EC, and 19 patients with high-grade EC confirmed the upregulation of PRRC2A and SYDE2. These proteins are implicated in the translocation of SLC2A4, the regulation of MECP2, and extracellular matrix (ECM) proteoglycan pathways, all of which are associated with tumor growth. Our results demonstrate that DIA-based proteomic analysis of tissue washings enables the identification of potential biomarkers for endometrial cancer (EC). Moreover, this study highlights tissue washings as a promising biological fluid for biomarker discovery in EC.

Pathogenic variants in MT-RNR1 are classically associated with aminoglycoside-induced sensorineural hearing loss through disruption of the mitochondrial 12S rRNA decoding center. Their contribution to pediatric neurological disease remains poorly defined. We identified a novel homoplasmic MT-RNR1 variant, m.1014A>G, in a patient with drug-resistant focal epilepsy beginning at 9 months of age who remained undiagnosed after trio whole-exome sequencing filtered using an extensive epilepsy gene panel. The variant was also detected in her mother. Structural modeling suggests that the variant, affecting a highly conserved region of the mitochondrial 12S rRNA, may alter the mitochondrial small ribosomal subunit assembly. To investigate its pathogenicity, we performed comprehensive functional studies in patient-derived fibroblasts. Unlike canonical MT-RNR1 variants, m.1014A>G did not confer aminoglycoside toxicity. Functional in vitro studies on patients’ fibroblasts demonstrated increased 12S/16S rRNA ratios, reduced abundance of both mitoribosomal subunit proteins, decreased levels of mitochondrially encoded respiratory-chain subunits, and impaired oxidative phosphorylation. These abnormalities were accompanied by mitochondrial network fragmentation, increased mitochondria–lysosome colocalization suggestive of enhanced mitophagy and reduced mitochondrial DNA copy number. Altogether, the findings are consistent with defective mitoribosome assembly and altered mitochondrial translation, resulting in a bioenergetic defect. Our study points to a previously unrecognized candidate pathogenic mechanism associated with MT-RNR1 and may expand the phenotypic spectrum of MT-RNR1-related disorders to include maternally inherited infantile-onset epileptic encephalopathy. These findings highlight the importance of dedicated mitochondrial DNA analysis in children with unexplained early-onset epilepsy despite negative nuclear genomic testing.