IARS2 regulates proliferation, migration, and angiogenesis of human umbilical vein endothelial cells

SUMMARY OBJECTIVE: In this study, we aimed at investigating the role of isoleucyl-tRNA synthetase in the growth, migration, and angiogenesis of human umbilical vein endothelial cells and the underlying molecular mechanism. METHODS: To assess the role of isoleucyl-tRNA synthetase, we silenced isoleucyl-tRNA synthetase in human umbilical vein endothelial cells using lentiviral 2 specific short hairpin RNAs (short hairpin RNAs 1 and 2) and examined silencing efficiency using real time quantitative polymerase chain reaction and western blot analyses. Short hairpin RNAs 1-isoleucyl-tRNA synthetase had greater knockdown efficiency, it was used in the entire downstream analysis. Short hairpin RNAs 1- isoleucyl-tRNA synthetase silencing effects on cell proliferation, cell colony generation, cell migration, as well as angiogenesis were assessed using cell counting kit-8, colony development, cell migration, and angiogenesis tube formation assays, respectively. RESULTS: Compared to the control group, anti-isoleucyl-tRNA synthetase short hairpin RNAs significantly silenced isoleucyl-tRNA synthetase expression in human umbilical vein endothelial cells, and suppressed their proliferation, migration, and angiogenic capacity. To characterize the underlying mechanism, western blot analyses showed that isoleucyl-tRNA synthetase knockdown suppressed phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3β, and β-catenin. CONCLUSIONS: We have shown, for the first time, the critical role of isoleucyl-tRNA synthetase in human umbilical vein endothelial cells. Our data show that isoleucyl-tRNA synthetase knockdown suppresses human umbilical vein endothelial cell proliferation, migration, and angiogenesis. We have also shown that isoleucyl-tRNA synthetase knockdown suppresses phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3β, and β-catenin. Together, these data highlight isoleucyl-tRNA synthetase as a potential antitumor anti-angiogenic target.

Cloning, soluble expression and mutant activity analysis of lactate dehydrogenase gene from Plasmodium falciparum / 生物工程学报

To establish a platform for high throughput screening and in vitro evaluating novel metabolic enzyme-targeted inhibitors towards anti-malarial drugs, a lactate dehydrogenase gene of Plasmodium falciparum (PfLDH) was amplified from the Hainan isolate FCC1/HN. The fusion expression vectors, pGEX-2TK and pET-29a( + ), were utilized to introduce the PfLDH gene into strains of Escherichia coli, BL21 and BL21 (DE3), for over-expression. Consequently, the enzymatic activity of PfLDH was successfully detected in the suspension of lytic bacteria. The PfLDH gene cloned in pGEX-2TK was mainly expressed as inclusion bodies, while the same gene cloned in pET-29a( + ) was nearly expressed in a soluble form of PfLDH, demonstrating the latter vehicle might be more suitable for the large-scale preparation of recombinant PfLDH. Furthermore, according to the electrophoregram of SDS-PAGE and the sequencing data, a series of truncated PfLDH sequences generated randomly from gene amplification were screened and cloned, from which four pre-matured genes with a terminator mutation, PfLDH-delta271, -delta236, -delta167 and -delta53 coding for 45, 80, 149 and 263 amino acid residues, were individually recovered. Through the gene expression and enzymatic activity measurement, the effect of pre-matured terminator mutation on the activity of PfLDH was evaluated, which should pave the way for probing the relationship between structure and function of PfLDH.

Establishment of stably expressed human RANTES gene in prunella vulgaris cell clone / 生物工程学报

To express interesting human genes in herbal cells for boosting their specific pharmacological activities, RANTES gene cloned from human peripheral blood lymphocyte (PBL) mRNA was introduced into A. tumefaciens strain LBA4404 harboring pAL4404 plasmid via tumor-inducing (Ti) plasmid-derived intermediate expression vector pROKII. In vitro cultured P. vulgaris cells were transformed by leaf-disk cocultivation procedure. Integration of RANTES gene in the genome of transformed cells was confirmed by Southern blotting, and expression of RANTES gene in transformed cells was analyzed by RT-PCR amplification, Western blotting and enzyme-linked immunosorbent assay (ELISA). The peroxidase activity of PBL was utilized as a detection index of cellular chemotropism induction by recombinant RANTES. The results have shown the RANTES gene was integrated in transgenic P. vulgaris cells, and RANTES gene-stably expressed cell clones were available, which could pave the way to obtain transgenic P. vulgaris plants demonstrating specific pharmacological activities.