Cartilage oligomeric matrix protein is a novel notch ligand driving embryonic stem cell differentiation towards the smooth muscle lineage

Abstract

Cartilage oligomeric matrix protein (COMP), a protective component of vascular extracellular matrix (ECM), maintains the homeostasis of mature vascular smooth muscle cells (VSMCs). However, whether COMP modulates the differentiation of stem cells towards the smooth muscle lineage is still elusive. Firstly, purified mouse COMP directly induced mouse embryonic stem cell (ESC) differentiation into VSMCs both in vitro and in vivo, while the silencing of endogenous COMP markedly inhibited ESC-VSMC differentiation. RNA-Sequencing revealed that Notch signaling was significantly activated by COMP during ESC-VSMC differentiation, whereas the inhibition of Notch signaling attenuated COMP-directed ESC-VSMC differentiation. Furthermore, COMP deficiency inhibited Notch activation and VSMC differentiation in mice. Through silencing distinct Notch receptors, we identified that Notch1 mainly mediated COMP-initiated ESC-VSMC differentiation. Mechanistically, COMP N-terminus directly interacted with the EGF11-12 domain of Notch1 and activated Notch1 signaling, as evidenced by co-immunoprecipitation and mammalian two-hybrid assay. In conclusion, COMP served as a potential ligand of Notch1, thereby driving ESC-VSMC differentiation.

Cartilage oligomeric matrix protein is an endogenous β-arrestin-2-selective allosteric modulator of AT1 receptor counteracting vascular injury

“…The cDNA encoding the mouse AT1a (NCBI Reference sequence: NM_177322.3) receptor was subcloned in-frame into the Flag vector to generate the indicated plasmids. For the co-IP assay, COS-7 cells were transfected with these plasmids and then incubated with the purified COMP protein 75 for 30 min. The cell lysates were incubated with an anti-Flag antibody or control IgG followed by Protein A/G agarose beads, and COMP protein expression was examined using western blot analysis.…”

Cartilage Oligomeric Matrix Protein–Derived Peptides Secreted by Cartilage Do Not Induce Responses Commonly Observed during Osteoarthritis

“…To screen for the possible functions of the peptides, we selected a single concentration of 100 nM for most of the assays. We based our choice on the maximum amount of peptides that 10 μg/mL of the parent protein COMP would release if COMP was completely cleaved, as COMP demonstrates bioactive effects in vitro at this concentration 17 , 18 and COMP is present in this concentration range in human serum. 19 …”

Vascular Smooth Muscle Cell Development and Cardiovascular Malformations

“…Notch3 was also required to maintain the smooth muscle gene expression profile and the morphological characteristics of the pulmonary artery after birth [72] . Our lab recently found that cartilage oligomeric matrix protein interacts with the activated Notch1 signaling pathway to drive ESC differentiation into VSMCs [73] …”

“…[72] Our lab recently found that cartilage oligomeric matrix protein interacts with the activated Notch1 signaling pathway to drive ESC differentiation into VSMCs. [73] Notch signaling is crucial for the NC precursors to differentiate into proper OFT patterns and in aortic arch artery formation. Suppressing Notch activity in these cells in mice causes malformation of the smooth muscle layer of the aortic arteries, resulting in congenital heart defects, namely, pulmonary artery stenosis and aortic arch patterning defects.…”