Conserved and context-dependent roles for Pdgfrb signaling during zebrafish vascular mural cell development

Abstract

Platelet derived growth factor beta and its receptor, Pdgfrb, play essential roles in the development of vascular mural cells, including pericytes and vascular smooth muscle. To determine if this role was conserved in zebrafish, we analyzed pdgfb and pdgfrb mutant lines. Similar to mouse, pdgfb and pdgfrb mutant zebrafish lack brain pericytes and exhibit anatomically selective loss of vascular smooth muscle coverage. Despite these defects, pdgfrb mutant zebrafish did not otherwise exhibit circulatory defects at larval stages. However, beginning at juvenile stages, we observed severe cranial hemorrhage and vessel dilation associated with loss of pericytes and vascular smooth muscle cells in pdgfrb mutants. Similar to mouse, pdgfrb mutant zebrafish also displayed structural defects in the glomerulus, but normal development of hepatic stellate cells. We also noted defective mural cell investment on coronary vessels with concomitant defects in their development. Together, our studies support a conserved requirement for Pdgfrb signaling in mural cells. In addition, these mutants provide an important model for definitive investigation of mural cells during early embryonic stages without confounding secondary effects from circulatory defects.

Activation of an injury-associated transient progenitor state in the epicardium is required for zebrafish heart regeneration

“…Besides these contaminating clusters, cluster 6 was identified as mural cells expressing platelet-derived growth factor receptor beta pdgfrb (Figure 2C) 29, 30 . Further analysis of the mural cells demonstrated enriched transcripts for known pericyte and vascular smooth muscle cell markers, including tropomyosin 1 ( tpm1 ), notch receptor 3 ( notch3 ), regulator of G protein signaling 5a ( rgs5a ), myosin heavy chain 11a ( myh11a ), actin alpha 2 smooth muscle ( acta2 ), transgelin ( tagln ), ATP-binding cassette sub-family C member 9 ( abcc9 ), and chemokine C-X-C motif ligand 12b ( cxcl12b ), as well as two recently identified mural cell markers NDUFA4 mitochondrial complex associated like 2a ( ndufa4l2a ) and potassium voltage-gated channel Isk-related family member 4 ( kcne4 ) 31, 32 (Figure S2C).…”

Integrated molecular analysis identifies a conserved pericyte gene signature in zebrafish

“…First, genes enriched in wild type pdgfrb:citrine -positive compared to - negative cells (log 2 fold change>1, adjp<0.05; Table S2.1 ). Second, genes reduced in pdgfrb:citrine -positive cells from pdgfrb um148 mutants, which lack pericytes (Ando et al, 2021), compared to wild type siblings at 5 dpf (log 2 fold change<-1, adjp<0.05; Table S2.2 ). Intersection of these datasets revealed 23 out of 105 pericyte genes with enrichment in pdgfrb:citrine cells and reduction in pdgfrb um148 mutants ( Fig.…”

“…These lines are referred to as: TgBAC(kcne4:sfgfp) um333 and TgBAC(ndufa4l2a:sfgfp) um382 . Imaging of larval stages was performed by confocal microscopy as described elsewhere (Ando et al, 2021).…”

“…Subsequent studies in mouse and zebrafish suggest that this is a conserved aspect of pericyte development (Ando et al, 2019; Simon et al, 2012). A number of signaling pathways have also been implicated in early pericyte development, including Platelet derived growth factor beta receptor (Pdgfrb), which is highly expressed on pericytes, and its endothelial-expressed ligand (Pdgfb), along with components of the Notch signaling pathway (Ando et al, 2021; Dieguez-Hurtado et al, 2019; Hellstrom et al, 1999; Kofler et al, 2015; Levéen et al, 1994; Lindahl et al, 1997; Wang et al, 2014). However, little is known about the stepwise acquisition of pericyte identity during embryonic development.…”

“…However, these efforts have largely focused on adult mouse tissues and studies at embryonic stages, or in other vertebrate models, are lacking. In the zebrafish embryo, which has proven useful for investigating pericyte development, only a few pericyte-specific genes have been identified, limiting the utility of this model (Ando et al, 2016; Ando et al, 2021; Ando et al, 2019). To address this issue, we have applied scRNA-seq on pdgfrb -positive cells isolated from zebrafish larvae, along with parallel integration with related datasets, to better define a pericyte gene signature.…”