Evaluation and comparison of cytotoxicity, genotoxicity, and apoptotic effects of poly-l-lysine/plasmid DNA micro- and nanoparticles.

The principal impediment to gene therapy is the development of efficient, nontoxic gene carriers that can handle and deliver foreign genetic materials into various cell types, including healthy and cancerous cells. Poly-l-lysine (PLL) polymers are one of the most favorable gene carriers among nonviral vectors, and PLL had low transfection and safety issues. The purpose of this study was to measure cellular toxicity, DNA damage, and apoptotic effects of PLL nanoparticles. Neuro2A mammalian cells were cultured and exposed to PLL/DNA complexes at different polymer/DNA ratios (C/P ratio 2 and 6) for 24 h. To evaluate metabolic activity, genotoxicity, and apoptotic influences of PLL nanoparticle, the following experimental methods were employed, in order: 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), DNA damage (COMET analysis) assay, and sub-G1 peak apoptosis assay. Our data indicate that toxicity is concentration dependent and a high concentration of polymer declined the metabolic activity. In addition, largest complexes (C/P 6 in HEPES buffered saline buffer) have slighter negative impact on metabolic activity. In agreement with our cytotoxicity data, apoptotic assay result represented that increase in size of PLL/DNA complexes decrease the number of apoptotic cells. Also, there was a remarkable increase in percent tail DNA of Neuro2A cells treated with higher concentration of PLL and its polyplexes. The present study demonstrated that PLL/DNA complexes caused cytotoxic, apoptotic, and genotoxic effects in a dose-dependent and weight ratio-dependent manner, which also affected the size of polyplexes.

E-selectin and L-selectin polymorphisms in patients with periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is a multifactorial disease in which environmental and genetic determinant factors contribute to individual subjects susceptibility. A DNA polymorphism in the regulating region of adhesion molecule genes is suggested to modulate the molecules physiological effects. The aim of this study was to investigate the genetic association between the E-selectin Ser128Arg and L-selectin Phe206Leu polymorphisms and periodontitis. MATERIAL AND METHODS: DNA was isolated from the whole blood of 88 patients with periodontitis and 139 healthy individuals. All samples were genotyped for the E-selectin Ser128Arg and L-selectin Phe206Leu polymorphisms using the polymerase chain reaction with sequence specific primers. RESULTS: Our findings revealed a significant difference in the Ser128Arg polymorphism of E-selectin, but not in the L-selectin polymorphism, between periodontal patients and controls. The 128Arg allele was present more frequently in patients than in healthy individuals (31.25% vs. 12.2%, p < 0.0001). In addition, there was an association between the presence of the 128Arg allele and periodontitis (odds ratio 2.9; 95% confidence interval: 1.75-4.4, p < 0.0001). No significant association was found between the polymorphisms tested and the subgroups of periodontal disease (i.e. chronic periodontitis and aggressive periodontitis). CONCLUSION: The findings of this study showed that the Ser128Arg polymorphism of E-selectin might contribute to the susceptibility of Iranian individuals to periodontitis.