Adenoviral delivery of human CDC5 promotes G2/M progression and cell division in neonatal ventricular cardiomyocytes

Abstract

Heart failure results from the cumulative death of cardiomyocytes, and the inability of remaining cells to regenerate. Efforts toward transcriptional reprogramming of cardiomyocytes by overexpressing E1A or E2F1 have been limited by the inability of cardiomyocytes to enter and complete mitosis. Human CDC5 (hCDC5), a component of the pre-mRNA splicing complex, has been shown to regulate G2/M transit in asynchronously dividing cells. We now show that co-infection of recombinant adenoviruses expressing E1A/E1B and hCDC5 promotes cell cycle re-entry and G2/M progression in post-mitotic cardiomyocytes. Co-expression of E1A/E1B and hCDC5 induced nuclear localization of cyclin-dependent kinase 1 and cyclin B1, and was sufficient to promote mitotic entry as determined by an increase in mitotic index only in co-infected cells. E1A/E1B and hCDC5 promoted cell division, as evidenced by an increase in the number of cardiomyocytes following co-infection. Thus, overexpression of E1A/E1B and hCDC5 resulted in cell cycle re-entry, DNA synthesis, cell division, and an increase in cardiomyocyte number, suggesting the formation of new cardiomyocytes. These studies suggest that G1/S-phase transcriptional regulators, in combination with pre-mRNA splicing factors, such as CDC5, that regulate rate-limiting G2/M target genes may prove useful in developing therapies to stimulate myocardial regeneration. Gene Therapy (2006) 13, 837-843.

Splicing to Keep Cycling: The Importance of Pre-mRNA Splicing during the Cell Cycle

“…[87] (Figure 1). Depletion of CDC5L causes dramatic mitotic arrest, chromosome 220 misalignments and sustained activation of spindle assembly checkpoint [85, [88][89][90]. The mechanism can be inferred from data showing that CDC5L modulates the pre-mRNA splicing 222 of a set of genes involved in mitosis [89].…”

Leptin Signaling and Obesity

“…153 We recently found that leptin deficiency or resistance results in increased cardiomyocyte apoptosis, as assessed by TUNEL staining and caspase-3 levels. 154 Aged ob/ob and db/db mice showed increased DNA damage compared with old WT mice.…”

Heart neurons use clock genes to control myocyte proliferation

“…Increased levels of Cdk1/cyclin B1 or decreased Cdk1 phosphorylation at Tyr 15 at P7 induces cardiomyocyte proliferation and entry to mitosis ( 15 , 53 ). Therefore, the balance between Wee1 and Cdc25 to regulate Cdk1 phosphorylation is critical for cardiomyocyte mitosis ( 15 , 43 , 54 ). Our data support the idea that decreased expression of both Per1 and Per2 clock genes increases cardiomyocyte proliferation and mitosis entry through suppression of Wee1.…”

“…To test this, we checked the levels of Cdk1/ cyclin B1, a protein complex for mitosis entry whose activity is regulated by Wee1 via phosphorylation (Fig. 5A) (15,43). Both mutant hearts showed decreased levels of inactive phospho-Cdk1 (Tyr 15 ) and increased levels of active Cdk1 and cyclin B1 (Fig.…”