Integrin-targeting block copolymer probes for two-photon fluorescence bioimaging

Targeted molecular imaging with two-photon fluorescence microscopy (2PFM) is a powerful technique for chemical biology and, potentially, for noninvasive diagnosis and treatment of a number of diseases. The synthesis, photophysical studies, and bioimaging are reported for a versatile norbornene-based block copolymer multifunctional scaffold containing biocompatible (PEG), two-photon fluorescent dyes (fluorenyl) and targeting (cyclic-RGD peptide) moieties. The two bioconjugates, containing two different fluorenyl dyes and cRGDfK covalently attached to the polymer probe, formed a spherical micelle and self-assembled structure in water, for which size was analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Cell viability and 2PFM imaging of human epithelial U87MG cell lines that overexpress α(v)β(3) integrin was performed via incubation with the new probes, along with negative control studies using MCF-7 breast cancer cells and blocking experiments. 2PFM microscopy confirmed the high selectivity of the biocompatible probe in the integrin-rich area in the U87MF cells while blocking as well as negative control MCF-7 experiments confirmed the integrin-targeting ability of the new probes.     

Non-synonymous polymorphisms in the P2RX 4 are related to bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

In the present study we investigated whether single nucleotide polymorphisms (SNPs) in the P2RX₄, which alter the P2X₄R function, are associated with the development of osteoporosis and whether an interaction between the P2X₄R and P2X₇R confer a synergistic effect of these two receptors on osteoporosis risk. Patients with fracture (690 females and 231 males, aged ≥50 years) were genotyped for three non-synonymous P2X₄R SNPs. Bone mineral density (BMD) was measured at the total hip, lumbar spine, and femoral neck. Subject carrying the variant allele of the Tyr315Cys polymorphism showed a 2.68-fold (95 % CI, 1.20–6.02) higher risk of osteoporosis compared with wild-type subject. Furthermore, significant lower lumbar spine BMD values were observed in subjects carrying the Cys315 allele as compared with wild-type (0.85 ± 0.17 and 0.93 ± 0.17 g/cm², respectively; p < 0.001). Assuming a recessive model, carriers of the variant allele of the Ser242Gly polymorphism showed increased BMD values at the lumbar spine compare to wild-type subject (1.11 ± 0.35 and 0.92 ± 0.17 g/cm², respectively; p = 0.0045). This is the first study demonstrating an association of non-synonymous polymorphisms in the P2RX₄ and the risk of osteoporosis, suggesting a role of the P2X₄R in the regulation of bone mass.

Electronic supplementary material

The online version of this article (doi:10.1007/s11302-012-9337-0) contains supplementary material, which is available to authorized users.     

Adh 1 first intron polymorphisms in Argentinean populations of Ceratitis capitata

DNA size polymorphisms were utilized in a study of 24 natural populations of Ceratitis capitata Wiedemann (Diptera: Tephritidae) from Argentina. The first intron of alcohol dehydrogenase 1 gene (Adh₁) was amplified using exon priming intron crossing‐polymerase chain reaction. Three size variants were detected among the 307 samples analyzed. To better differentiate the size variants, further digestion of PCR products with the EcoRI restriction enzyme was carried out. Complete nucleotide sequences of the three‐allele variants were obtained and single changes, insertions, deletions, and EcoRI recognition sites were located. Population allele frequencies were analyzed and a global mean heterozygosity (He) of 0.33 was obtained. In most populations, observed allelic frequencies conformed to Hardy–Weinberg expectations. Significant differences between provinces and sampling sites within these provinces, and among some populations were found. The average number of insects exchanged among populations (Nm) was estimated and high values were observed between Argentina and populations from two African countries (Morocco and Kenya), Australia, and Hawaii (Kauai). Pest introduction sources and dispersion patterns in Argentina are discussed based on these results as well as on available bibliographical data.