Construction of a plasmid for expression of rat platelet-derived growth factor C and its effects on proliferation, migration and adhesion of endothelial progenitor cells

Expression and function of PDGF-C in development and stem cells

Platelet-derived growth factor C (PDGF-C) is a relatively new member of the PDGF family, discovered nearly 20 years after the finding of platelet-derived growth factor A (PDGF-A) and platelet-derived growth factor B (PDGF-B). PDGF-C is generally expressed in most organs and cell types. Studies from the past 20 years have demonstrated critical roles of PDGF-C in numerous biological, physiological and pathological processes, such as development, angiogenesis, tumour growth, tissue remodelling, wound healing, atherosclerosis, fibrosis, stem/progenitor cell regulation and metabolism. Understanding PDGF-C expression and activities thus will be of great importance to various research disciplines. In this review, however, we mainly discuss the expression and functions of PDGF-C and its receptors in development and stem cells.

Effects of small interfering RNA-mediated silencing of susceptibility genes of non-syndromic cleft lip with or without cleft palate on cell proliferation and migration

BACKGROUND

Non-syndrome cleft lip with or without cleft palate (NSCL/P) is the most common congenital defect with a complex etiology involving both genetic and environmental factors. Our previous research has identified susceptibility genes of NSCL/P using whole-exome sequencing. The study was to determine the effects of small interfering RNA (siRNA)-mediated silencing of genes on cell proliferation and migration to confirm the roles of the genes in NSCL/P.

METHODS

We silenced the genes by RNA interference (RNAi) with siRNA in human oral keratinocyte (HOK). We used the Cell Counting Kit-8 (CCK8) assay to determine cell proliferation and the wound healing assay to determine cell migration.

RESULTS

Migration of HOK was inhibited by RNAi-induced silencing of adenosine triphosphate binding cassette transporter A4 (ABCA4), erythropoietin produces hepatocyte A receptor 3 (EPHA3), alpha-parvin (PARVA), and platelet-derived growth factor C (PDGFC). The change of proliferation was not found. Treated with siRNA-mediated silencing of type IV collagen (COL4A2), eukaryotic translation initiation factor 2B subunit (EIF2B3), fibroblast growth factor receptor 2 (FGFR2), kinesin family member 20B (KIF20B), β-lactamase serine-like protein (LACTB), SEC16 homolog A (SEC16A) and thyroid adenoma target gene (THADA) had no effects on cell proliferation and migration of HOK.

CONCLUSIONS

We suggest mutations of the four susceptibility genes ABCA4, EPHA3, PARVA and PDGFC are involved in NSCL/P through inhibiting cell migration. The study provides new candidates for future study of NSCL/P.

Platelet‑derived growth factor D promotes the angiogenic capacity of endothelial progenitor cells

Neovascularization and re-endothelialization rely on endothelial progenitor cells (EPCs). However, the recruitment and angiogenic roles of EPCs are subject to regulation through the vascular microenvironment, which remains largely unknown. Platelet-derived growth factor D (PDGF-D) is a new member of the PDGF family that binds the PDGFR-β homodimer. However, it remains unknown whether and how it affects the angiogenic capacity of EPCs and participates in tube-like formation. EPCs were derived from rat bone marrow cells, and the gain-of-function approach was used to study the effects of PDGF-D on the biological activities of EPCs. EPCs that stably express PDGF-D were generated by lentiviral-mediated transduction, and the expression levels were evaluated by western blotting and reverse transcription, followed by real-time quantitative polymerase chain reaction (RT-qPCR). The biological activities of EPCs evaluated in the present study included proliferation, adhesion, migration, tube formation and senescence. Furthermore, the downstream signaling of PDGF-D was explored by western blot analysis. The results revealed that the lentiviral-mediated expression of PDGF-D in the microenvironment promoted the migration, proliferation, adhesion and tube formation of EPCs. In addition, PDGF-D suppressed the senescence of EPCs. Mechanistically, PDGF-D induced the phosphorylation of several signaling molecules, including STAT3, AKT, ERK1/2, mTOR and GSK-3β, suggesting that PDGF-D enhanced the angiogenic function of EPCs through PDGF receptor-dependent and -independent signaling pathways. In conclusion, PDGF-D promotes the angiogenic capacity of EPCs, including proliferation, migration, adhesion and tube formation, and thereby contributes to angiogenesis.

Vascular stem/progenitor cells: functions and signaling pathways

Vascular stem/progenitor cells (VSCs) are an important source of all types of vascular cells needed to build, maintain, repair, and remodel blood vessels. VSCs, therefore, play critical roles in the development, normal physiology, and pathophysiology of numerous diseases. There are four major types of VSCs, including endothelial progenitor cells (EPCs), smooth muscle progenitor cells (SMPCs), pericytes, and mesenchymal stem cells (MSCs). VSCs can be found in bone marrow, circulating blood, vessel walls, and other extravascular tissues. During the past two decades, considerable progress has been achieved in the understanding of the derivation, surface markers, and differentiation of VSCs. Yet, the mechanisms regulating their functions and maintenance under normal and pathological conditions, such as in eye diseases, remain to be further elucidated. Owing to the essential roles of blood vessels in human tissues and organs, understanding the functional properties and the underlying molecular basis of VSCs is of critical importance for both basic and translational research.

Platelet-derived growth factor-C and -D in the cardiovascular system and diseases

The cardiovascular system is among the first organs formed during development and is pivotal for the formation and function of the rest of the organs and tissues. Therefore, the function and homeostasis of the cardiovascular system are finely regulated by many important molecules. Extensive studies have shown that platelet-derived growth factors (PDGFs) and their receptors are critical regulators of the cardiovascular system. Even though PDGF-C and PDGF-D are relatively new members of the PDGF family, their critical roles in the cardiovascular system as angiogenic and survival factors have been amply demonstrated. Understanding the functions of PDGF-C and PDGF-D and the signaling pathways involved may provide novel insights into both basic biomedical research and new therapeutic possibilities for the treatment of cardiovascular diseases.