Background and Objectives: Neuropeptide Y (NPY) family peptides and dipeptidyl peptidase-4 (DPP-4) are involved in gastrointestinal regulation and may contribute to obesity and type 2 diabetes mellitus (T2DM) pathophysiology. This study investigates their expression in jejunal muscular tissue and associations with gastrointestinal symptoms in patients with obesity, with (OB+/DM+) and without T2DM (OB+/DM−). Materials and Methods: This cross-sectional study includes forty-four patients undergoing laparoscopic Roux-en-Y gastric bypass divided based on T2DM status. Gastrointestinal symptoms were assessed using the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire, and jejunal tissue samples were analyzed for DPP-4, NPY, peptide YY (PYY), and pancreatic polypeptide (PP) mRNA and protein levels. Results: DPP-4, NPY, PYY, and PP gene expression in jejunal muscular tissue was similar between groups. In the OB+/DM+ group, PP protein was higher, while DPP-4 and PYY were lower compared to the OB+/DM− group. Significant positive correlations between DPP-4 and NPY, PYY, and PP were found in the OB+/DM− group, while only DPP-4 and PYY correlated in the OB+/DM+ group. Gastrointestinal symptoms in the OB+/DM− group showed positive correlations with PP (abdominal pain), DPP-4 (indigestion), and NPY (constipation). Conclusions: The study demonstrates significant differences in DPP-4, PYY, and PP protein expression between patients with obesity, with or without T2DM. Peptide correlations with gastrointestinal symptoms in non-diabetic patients suggest distinct regulatory mechanisms, warranting further research.

Colorectal cancer (CRC) encompasses biologically diverse cellular phenotypes with distinct microRNA (miRNA) expression patterns. Assessing whether cell-model-derived alterations recur in extracellular vesicles (EVs) and human tumors may help prioritize candidates with broader relevance to CRC. We performed small RNA sequencing of non-malignant HCoEpiC cells, differentiated enterocyte-like Caco-2 cells, less differentiated HCT116 cells, and their corresponding EVs. miRNAs showing concordant dysregulation in both CRC cell lines relative to HCoEpiC, with greater absolute log₂ fold changes in HCT116, were prioritized and evaluated in human colorectal tissues and TCGA-COAD/READ. Seven of 29 prioritized cellular miRNAs met the EV selection criteria. Of the 26 candidates measurable in the patient-tissue dataset, eight showed FDR-significant, directionally concordant differences between CRC and healthy colorectal tissues, including five concordantly dysregulated across cells, EVs, and patient tissues. Analysis of 11 matched TCGA tumor–non-tumor pairs reproduced reduced miR-30a-3p, miR-30c-2-3p, and miR-1271-5p and increased miR-140-5p expression. Target-based enrichment and exploratory miRNA-mRNA correlation analyses identified associations with CRC-relevant signaling and MYC-related, cell-cycle, DNA-repair, and metabolic programs. No significant associations with the evaluated clinicopathological features or overall survival were detected. Collectively, these findings identify a reproducible subset of CRC-associated miRNA alterations and highlight reduced miR-30a-3p and miR-30c-2-3p expression as a recurrent family-level pattern warranting mechanistic investigation.