Purpose: Aging leads to immune dysfunction, including altered T-cell phenotypes such as the ­CD5 low state. This study investigated how the exon switch regulates CD5 expression in aging in an interleukin-10 (IL-10)-dominated environment and the involvement of CCAAT/enhancer-binding protein beta (CEBP-β) in this process. Methods: The expression of messenger RNA (mRNA) was analyzed for E1A and E1B in T cells from young and older adults. The effect of IL-10 treatment on the exon switch was assessed by measuring the E1A and E1B mRNA expression in young T cells. MatInspector analysis identified CEBP-β binding sites upstream of E1A and E1B start sites.The effect of IL-10 on CEBP-β isoforms expression was assessed using western blot, and that on CEBP-β binding onto the E1A and E1B upstream was assessed using chromatin immunoprecipitation assays. The short hairpin RNA (shRNA) silencing of CEBP-β was performed to confirm its role in E1A/E1B expression. Results: Older individuals showed increased E1B and decreased E1A mRNA expression. IL-10 treatment of young T cells persuaded a similar shift. IL-10 changed CEBP-β binding, reducing its association with the E1B upstream region while increasing its binding to E1A. IL-10 also upregulated the liver-enriched inhibitory protein of CEBP-β. shRNA silencing of CEBP-β reduced E1B expression. Conclusion IL-10-driven exon switching alters CD5 expression in aged T cells, increasing E1B and decreasing E1A through CEBP-β regulation. These findings reveal a novel mechanism underlying fundamental immune aging and suggest potential targets for immune modulation. These insights may have clinical implications in chronic inflammatory diseases, autoimmune disorders, and cancer therapies.

BACKGROUND AND OBJECTIVES: Most studies in cardiac regeneration have explored bone marrow mesenchymal stem cells (BM-MSC) with variable therapeutic effects. Amniotic fluid MSC (AF-MSC) having extended self-renewal and multi-potent properties may be superior to bone marrow MSC (BM-MSC). However, a comparison of their cardiomyogenic potency has not been studied yet.METHODS: The 5-azacytidine (5-aza) treated AF-MSC and BM-MSC were evaluated for the expression of GATA-4, Nkx2.5 and ISL-1 transcripts and proteins by quantitative RT-PCR and Western blotting, respectively as well as for the expression of cardiomyogenic differentiation markers cardiac troponin-T (cTNT), beta myosin heavy chain (βMHC) and alpha sarcomeric actinin (ASA) by immunocytochemistry.RESULTS: The AF-MSC as compared to BM-MSC had significantly higher expression of GATA-4 (183.06±29.85 vs. 9.80±0.05; p<0.01), Nkx2.5 (8.3±1.4 vs. 1.82±0.32; p<0.05), and ISL-1 (39.59±4.05 vs. 4.36±0.39; p<0.01) genes as well as GATA-4 (2.01±0.5 vs. 0.6±0.1; p<0.05), NKx2.5 (1.9±0.14 vs. 0.8±0.2; p<0.01) and ISL-1 (1.7±0.3 vs. 0.9±0.1; p<0.05) proteins. The AF-MSC also had significantly elevated expression of cTNT (5.0×10⁴±0.6×10⁴ vs. 3.5 ×10⁴±0.8×10⁴; p<0.01), β-MHC (15.7×10⁴±0.9×10⁴ vs. 8.2×10⁴±0.6×10⁴; p<0.01) and ASA (18.6×10⁴±4.9×10⁴ vs. 13.1×10⁴±3.0×10⁴; p<0.05) than BM-MSC.CONCLUSIONS: Our data suggest that AF-MSC have greater cardiomyogenic potency than BM-MSC, and thus may be a better source of MSC for therapeutic applications in cardiac regenerative medicine.
Actinin ; Amniotic Fluid ; Antigens, Differentiation ; Azacitidine ; Blotting, Western ; Bone Marrow ; Female ; Humans ; Immunohistochemistry ; Mesenchymal Stromal Cells ; Regeneration ; Regenerative Medicine ; Therapeutic Uses ; Troponin T ; Ventricular Myosins