Abstract 15510: Canonical Wnt Signaling Reverses the ‘Aged/Senescent’ Phenotype of Human Endogenous Cardiac Stem Cells
The adult human myocardium harbours endogenous, multi-potent cardiac stem cells (eCSCs), however aging/senescence of eCSCs determines their function and regenerative capacity. We assessed whether the ‘aged’ human eCSC phenotype could be reversed by promoting ‘youthful’ Wnt signalling. c-kitpos CD45neg CD31neg eCSCs were isolated from the right atrial appendage of different aged patients (32-85 years) using MACS (Miltenyi). Freshly isolated eCSCs were characterised for co-expression of ageing/senescence markers (p16INK4a, SA-β-galactosidase) with known multipotency (Oct-4, Sox2, Nanog, Bmi-1, TERT) and proliferation (Ki67) markers. Telomere length of eCSCs was determined using Q-FISH analysis. DNA damage was assessed using γ-H2AX. The growth, clonogenicity, differentiation potential and senescence associated secretory phenotype (SASP) of eCSCs from young and old patients were evaluated. The number of eCSCs isolated was similar regardless of age, gender and pathology (~45,000 eCSCs/gram of tissue). Freshly isolated eCSCs showed age-correlated increased expression of senescent markers and decreased expression of multipotency and proliferation markers. eCSCs isolated from old hearts harbour a greater proportion of eCSCs with critically short telomeres and DNA damage. ‘Aged-senescent’ eCSCs showed limited cloning and growth capacity, impaired cardiac differentiation and increased SASP expression, relative to younger eCSCs. Treatment with the canonical Wnt ligand, Wnt3a significantly increased the proliferation of ‘aged-senescent’ eCSCs to levels observed in younger eCSCs. Conversely a switch to non-canonical Wnt signalling decreased the proliferation of eCSCs while siRNA knockdown of the canonical Wnt mediator, β-catenin revealed a similar impairment effect on eCSC proliferation. In conclusion, manipulation of canonical and non-canonical Wnt signalling pathways reverses the ‘aged/senescent’ phenotype.
Author Disclosures: F.C. Lewis: None. T. Teoh: None. E. Domenj?-Vila: None. T. Theologou: None. M. Field: None. W. Awad: None. G.M. Ellison-Hughes: None.
- © 2016 by American Heart Association, Inc.