Swaddle Abstract Although several tissues and chemokines orchestrate coronary formation, the guidance cues for coronary growth remain unclear.Here, we profile the juvenile zebrafish epicardium during coronary vascularization and identify hapln1a + cells enriched with vascular-regulating genes.hapln1a + cells not only envelop vessels but also form linear structures ahead of coronary sprouts.Live-imaging demonstrates that coronary growth occurs along these pre-formed structures, with depletion of hapln1a + cells blocking this growth.
hapln1a + cells also pre-lead coronary sprouts during regeneration and hapln1a + cell loss inhibits revascularization.Further, we identify serpine1 expression in hapln1a + cells adjacent to coronary sprouts, and serpine1 inhibition blocks vascularization and revascularization.Moreover, we observe the hapln1a substrate, hyaluronan, forming linear structures along and preceding coronary vessels.Depletion of hapln1a + cells or serpine1 activity inhibition disrupts hyaluronan structure.
Our studies reveal that hapln1a + cells Short Wellingtons and serpine1 are required for coronary production by establishing a microenvironment to facilitate guided coronary growth.