Cellular internalization of targeted and non-targeted delivery systems for contrast agents based on polyamidoamine dendrimers
RUSSIAN CHEMICAL BULLETIN
Authors: Sokol, M. B.; Faustova, M. R.; Nikolskaya, E. D.; Zhunina, O. A.; Fomicheva, M., V; Petrov, R., V; Yabbarova, N. G.
Abstract
New high-molecular-weight contrast agents based on polyamidoamine (PAMAM) dendrimers for targeted imaging of malignant tumors characterized by overexpression of human epidermal growth factor receptor (EGFR) and human alpha-fetoprotein receptor (RECAF) were designed. Conjugates of second (G2) and third (G3) generation polyamidoamine dendrimers with 1,4,7,10-tetraazocyclodecane-1,4,7,10-tetraacetic acid (DOTA) were obtained. The quantitative composition of the conjugates was determined by (HNMR)-H-1 spectroscopy. It was shown that four out of the 16 terminal NH2 groups in G2-DOTA and nine out of the 32 groups in G3-DOTA were modified with DOTA. The morphology, size, and charge of the synthesized macromolecules were characterized by dynamic light scattering and electrophoresis. Gadolinium(III) was loaded into the conjugates and the Gd content was determined by atomic emission spectroscopy. For increasing the selectivity of accumulation in the tumor cells, two recombinant proteins able to bind selectively to EGFR and RECAF, namely, human recombinant epidermal growth factor (rEGF) and human recombinant 3rd domain of alpha-fetoprotein (3dAFPpG), were conjugated with G2 and G3 dendrimers. The conjugates containing vector molecules were mainly accumulated via clathrin-dependent endocytosis, whereas G2-DOTA and G3-DOTA were absorbed via caveolin-dependent endocytosis and macropinocytosis. The dendrimer conjugates with vector molecules were intensely accumulated in A549 cells characterized by high expression of EGFR (Herl) and RECAF, whereas the accumulation of conjugates in the control K562 cells (with low expression of Her1) and in the CD14(-) population of human unstimulated mononuclear white blood cells was insignificant. The 3dAFPpG-conjugated dendrimers were partly recycled. All synthesized conjugates had a rather low toxicity in the range of 350-450 mu mol L-1 (IC50).
Genetic variation in toll like receptors 2, 7, 9 and interleukin-6 is associated with cytomegalovirus infection in late pregnancy
BMC MEDICAL GENETICS
Authors: Mhandire, Doreen Z.; Mhandire, Kudakwashe; Magadze, Mulalo; Wonkam, Ambroise; Kengne, Andre P.; Dandara, Collet
Abstract
Background Maternal cytomegalovirus (CMV) infection and/or reactivation in pregnancy is associated with a myriad of adverse infant outcomes. However, the role of host genetic polymorphisms in modulating maternal CMV status is inconclusive. This study investigated the possible association of single nucleotide polymorphisms in toll-like receptor (TLR) and cytokine genes with maternal plasma CMV DNA status in black Zimbabweans. Methods In a cross-sectional study, 110 women in late gestation who included 36 CMV infected cases and 74 CMV uninfected, age and HIV status matched controls were enrolled. Twenty single nucleotide polymorphisms in 10 genes which code for proteins involved in immunity against CMV were genotyped using Iplex GOLD SNP genotyping protocol on the Agena MassARRAY (R) system. Statistical analyses were performed using Stata SE and the 'Genetics' and 'SNPassoc' packages of the statistical package R. Results The TLR7 rs179008A > T (p < 0.001) polymorphism was associated while the TLR9 rs352139T > C (p = 0.049) polymorphism was on the borderline for association with CMV positive (CMV+) status. In contrast, the interleukin (IL)-6 rs10499563T > C (p < 0.001) and TLR2 rs1816702C > T (p = 0.001) polymorphisms were associated with CMV negative (CMV-) status. Furthermore, allele frequencies of SNPs in TLR2, TLR4, TLR9, TLR7, IL-6, IL-10, IL-28B, IL-1A and interferon AR1 (IFNAR1) genes are being reported here for the first time in a Zimbabwean population. The allele frequencies in the Zimbabwean population are generally comparable to other African populations but different when compared to European and Asian populations. Conclusions Toll-like receptor and interleukin genetic polymorphisms influence CMV status in late gestation among black Zimbabweans. This is attributable to possible modulation of immune responses to CMV reactivation in a population previously exposed to CMV infection.