MALT1 accelerates proatherogenic vascular smooth muscle cell growth, invasion and synthetic phenotype switching via nuclear factor-B signaling-dependent way

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) modulates T helper cell differentiation and nuclear factor-& kappa;B (NF-& kappa;B) pathway-mediated inflammation and potentially regulates lipid metabolism, which are all critical factors involved in atherosclerosis. The present study aimed to investigate the effect of MALT1 on the cellular functions of proatherogenic vascular smooth muscle cells (VSMCs). Therefore, to establish a human proatherogenic VSMC model, VSMCs were treated with different doses of oxidized low-density lipoprotein (oxLDL). Subsequently, the effect of MALT1 overexpression or knockdown in proatherogenic VSMCs treated with or without NF-& kappa;B activator was also explored. The results showed that treatment of proatherogenic VSMCs with oxLDL significantly elevated the mRNA and protein expression levels of MALT1 in a dose-dependent manner. Furthermore, MALT1 overexpression enhanced cell viability, invasion and phenotype switching and reduced apoptosis in proatherogenic VSMCs. However, MALT1 knockdown exerted the opposite effect on the above cellular functions. Additionally, the results revealed that MALT1 could positively regulate the NF-& kappa;B pathway in proatherogenic VSMCs. Moreover, treatment of proatherogenic VSMCs with NF-& kappa;B activator not only exacerbated the dysregulation of cellular functions, but also hampered the effect of MALT1 knockdown on attenuating cell growth, invasion and synthetic phenotype switching, thus suggesting that NF-& kappa;B was essential for the regulation of MALT1-triggered functions in proatherogenic VSMCs. In conclusion, the current study suggested that MALT1 could exacerbate cell viability, mobility and synthetic phenotype switching of proatherogenic VSMCs in a NF-& kappa;B signaling-dependent manner. Therefore, MALT1 could be considered as a potential therapeutic target for atherosclerosis.