EOLA1 protects lipopolysaccharide induced IL-6 production and apoptosis by regulation of MT2A in human umbilical vein endothelial cells

Abstract

Endothelial cell (EC) injury or dysfunction is believed to be mediated at least in part by lipopolysaccharide (LPS). Recent studies have shown that LPS induces apoptosis in different types of endothelium, including HUVEC. Previously we used EOLA1 (endothelial-overexpressed LPS-associated factor 1) cDNA as a bait and performed a yeast two-hybrid screening of a human liver cDNA library and identified metallothionein 2a (MT2a) as the associated protein. EOLA1 protein plays a role as a signal transduction factor. But the mechanism of EOLA1 mediated the protection of cell production of IL-6 and apopotosis in HUVEC is not known. MT2a is expressed in many kinds of cells and plays a role in inflammation. In this study, we demonstrated that LPS could induce EOLA1 expression in time-dependent and apparently contributed to the inhibition of IL-6 production and apoptosis induced by LPS treatment. We also found that deletion of EOLA1 promoted IL-6 production and apoptosis in the treatment of LPS in HUVEC. Furthermore, we demonstrated that MT2a was activated by LPS, and played a key role in LPS-induced IL-6 expression in HUVEC. We further provided the evidence that EOLA1 functioned as a negative regulator for LPS response by regulation of MT2a. These findings suggest that EOLA1 may have an important regulatory role during EC inflammatory responses.

EOLA1 Inhibits Lipopolysaccharide-Induced Vascular Cell Adhesion Molecule-1 Expression by Association with MT2A in ECV304 Cells

“…EOLA1 is weakly expressed under the steady condition and highly expressed in response to LPS in ECV304 cells. The discovery of the protein association between EOLA1 and metallothionein 2A (MT2A) has been confirmed by yeast double-hybridization and coimmunoprecipitation assay [ 2 , 5 ]. MT2A is known to have anti-inflammatory, antiendotoxin, and tumor-inhibiting effects in cell cultures [ 6 , 7 ].…”

HMBOX1 interacts with MT2A to regulate autophagy and apoptosis in vascular endothelial cells

“…Endothelial-overexpressed lipopolysaccharide (LPS)-associated factor 1 (EOLA1) interacts with MT2A in ECV304 cells 18 . This group also found that EOLA1 regulated MT2A to modulate HUVEC apoptosis during inflammatory responses 19 . In addition, in esophageal cancer cells, the interaction of esophageal cancer related gene 2 (ECRG2) and MT2A was suggested to play an important role in the carcinogenesis of esophageal cancer; ECRG2 co-localizing with MT2A was mostly in nuclei and slightly in cytoplasm 20 .…”

Exosomes from mesenchymal stromal cells reduce murine colonic inflammation via a macrophage-dependent mechanism

“…Metallothioneins are present in multiple tissues and mainly consist of 4 groups: metallothionein-1A, metallothionein-2, metallothionein-3, and metallothionein-4. It has been reported that metallothionein-2 serves as a critical regulator of numerous cell activities, including differentiation, apoptosis, autophagy, immune response, carcinogenesis, and drug resistance (28,(46)(47)(48)(49)(50). The effects of metallothionein-2 on pathophysiological processes, particularly inflammation, are subjects of many studies (51).…”

“…The effects of metallothionein-2 on pathophysiological processes, particularly inflammation, are subjects of many studies (51). A study by Liu et al showed that metallothionein-2 knockdown increased LPS-induced IL-6 production in endothelial cells (49), indicating a protective role against inflammatory responses. Takano and colleagues demonstrated that transgenic mice with metallothionein overexpression were more resistant to neutrophilic lung inflammation and lung edema induced by intratracheal challenge with LPS (52).…”