Perivascular cell-specific knockout of the stem cell pluripotency gene Oct4 inhibits angiogenesis

Abstract

The stem cell pluripotency factor Oct4 serves a critical protective role during atherosclerotic plaque development by promoting smooth muscle cell (SMC) investment. Here, we show using Myh11-CreER T2 lineage-tracing with inducible SMC and pericyte (SMC-P) knockout of Oct4 that Oct4 regulates perivascular cell migration and recruitment during angiogenesis. Knockout of Oct4 in perivascular cells significantly impairs perivascular cell migration, increases perivascular cell death, delays endothelial cell migration, and promotes vascular leakage following corneal angiogenic stimulus. Knockout of Oct4 in perivascular cells also impairs perfusion recovery and decreases angiogenesis following hindlimb ischemia. Transcriptomic analyses demonstrate that expression of the migratory gene Slit3 is reduced following loss of Oct4 in cultured SMCs, and in Oct4-deficient perivascular cells in ischemic hindlimb muscle. Together, these results provide evidence that Oct4 plays an essential role within perivascular cells in injury- and hypoxia-induced angiogenesis.

Pericyte Bridges in Homeostasis and Hyperglycemia

“…The goal of the present studies was to examine whether pericyte detachment from the microvasculature and formation of cellular bridges are potentially key early events in diabetes that may set the stage for subsequent vascular compromise. We establish the phenotypic identity of these cell bridges using immunolabeling for Myh11, a pericyte-specific marker, and then confirmed these results using a lineage-tracing genetic reporter driven by the Myh11 promoter (16). Next, we tested whether pericyte bridges could be reversibly enriched through acute elevation of blood glucose or delivery of exogenous chemokines known to be elevated in the diabetic microenvironment (17,18).…”

Pericyte Bridges in Homeostasis and Hyperglycemia: Reconsidering Pericyte Dropout and Microvascular Structures

“…show that: (1) pericyte-like bridging cells are, indeed, pericytes, and they retained their identity in the stimuli investigated,(2) the observed increase in pericyte bridges occurs in the absence of other microvascular remodeling events such as angiogenesis or regression that have been documented in hyperglycemia, (3) this increase in pericyte bridges is a reversible process by delivery of insulin, (4) pericytes are capable of active movement in adult vasculature and pericyte-specific deletion of KLF4, a transcription factor implicated in restricting cell migration, increases the abundance of pericyte bridges in the retina, and (5) pericyte bridges always colocalize with a basement membrane bridge, while endothelial cells never do.Our conclusion that pericyte-like cells are indeed pericytes is established based on their traced lineage from Myh11 promoter activity and expression of Myh11 protein, a contractile myosin previously shown in vascularized tissues to exhibit exclusive expression in smooth muscle cells and pericytes17 . Previous literature concluded that pericyte-like cells bridging capillaries were pericytes based on expression of NG2 14 or PDGFRβ 18 , both nonexclusive cell markers.…”

“…Previously, the Myosin Heavy Chain 11 (Myh11) promotor has been used in an inducible lineage tracing reporter mouse model to track the lineage of smooth muscle cells 37 . Myh11 lineage cells also colabel with the majority of NG2 or PDGFRβ expressing pericytes 17 , and have been used to study them. We hypothesized that pericyte bridges are marked in this mouse model, and the exclusivity of Myh11 expression could be leveraged to visualize pericyte morphology with higher confidence of cell identity than with NG2 or PDGFRβ as markers.…”

“…To begin to answer these questions, we first evaluated the phenotypic identity of these cell bridges using immunolabeling of a pericyte-specific marker and confirmed with a lineagetracing genetic reporter mouse driven by the same promoter, which enabled pericytes and their progeny to be fluorescently tagged with a high degree of specificity 17 . Given that all prior studies of these bridging cells have relied exclusively on non-specific proteins like NG2 and PDGFRβ 18 (which can be expressed by other cell types 19 , such as macrophages and microglia), we regarded this as a critical first step.…”

Oct4 Regulates the Transition of Cancer Stem-Like Cells to Tumor Endothelial-Like Cells in Human Liver Cancer

“…In these cases, Oct4 has been reported as a master regulator for the endothelial lineage transition from human iPSCs (Margariti et al, 2012;Li et al, 2013;Yoo et al, 2013). In addition, Hess et al (2019) demonstrated that Oct4 plays an essential role within the perivascular cells in injury-and hypoxia-induced angiogenesis. All these reports together indicate that Oct4 participates in angiogenesis as a master regulator in normal stem cells.…”