The Centriole as a Differentiation Ratchet: A Hypothesis and an Experimental Roadmap Built on the Naturally Acentriolar Adult Cardiomyocytes of Human, Mouse and Rat

The adult mammalian heart does not regenerate. After myocardial infarction, cardiomyocytes are lost permanently because the surviving cells are terminally differentiated and post-mitotic. Regenerative vertebrates such as zebrafish and newts retain proliferative, centriole-bearing cardiomyocytes and repair the heart completely, whereas mammals lose this capacity within the first postnatal week. I propose that the centriole functions as a differentiation ratchet: a heritable structural input that couples proliferative potential to centriole integrity through the mitotic surveillance pathway (MSP). The strongest natural evidence comes from the heart. Shortly after birth, mammalian cardiomyocytes undergo programmed centrosome disassembly, with pericentriolar material relocating to the nuclear envelope. Pharmacological depletion of centrioles is sufficient to drive the post-mitotic transition in human cardiomyocytes, and failure of this step is pathogenic: a mutation in the centrosomal gene RTTN causes infantile dilated cardiomyopathy. Because the adult cardiomyocyte is one of the few naturally and permanently acentriolar somatic cells, it offers a ready-made testbed for asking whether the ratchet can be reversed. A single-nucleus transcriptomic analysis of the developing human heart (fetal, young and adult) presented here shows that this shutdown is actively installed during maturation rather than a passive decay: adult cardiomyocytes reduce their centriolar program—PLK4, CEP192, SASS6, STIL and NEK2 are all down-regulated—while the p53 effector p21 (CDKN1A) is elevated, the signature of a p53-maintained post-mitotic lock. The roadmap proceeds in three steps, all conducted in cell culture: (i) release the G0 lock and assess TRIM37 and PLK1 status; (ii) restore a licensed centriole from an autologous low-entropy adult stem cell, with PLK1 and Ect2 co-delivery; and (iii) enforce a strict safety gate that includes TRIM37, p53 pathway, and contractile function assessment. Eight pre-registered, falsifiable hypotheses are stated below, and the principal risks are analyzed.