8 research outputs found

    Rescue of mitochondrial function in parkin-mutant Fibroblasts using drug loaded PMPC-PDPA polymersomes and tubular polymersomes

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    Mutations in parkin cause autosomal recessive Parkinsonism and mitochondrial defects. A recent drug screen identified a class of steroid-like hydrophobic compounds able to rescue mitochondrial function in parkin-mutant fibroblasts. Whilst these possess therapeutic potential, the size and high hydrophobicity of some may limit their ability to penetrate the blood-brain barrier from systemic circulation, something that could be improved by novel drug formulations. In the present study, the steroid-like compounds Ursolic Acid (UA) and Ursocholanic Acid (UCA) were successfully encapsulated within nanoscopic polymersomes formed by poly(2-(methacryloyloxy)ethyl phosphorylcholine)–poly(2-di-isopropylamino)ethyl methacrylate) (PMPC-PDPA) and separated into spherical and tubular morphologies to assess the effects of nanoparticle mediated delivery on drug efficacy. Following incubation with either morphology, parkin-mutant fibroblasts demonstrated time and concentration dependent increases in intracellular ATP levels, resembling those resulting from treatment with nascent UA and UCA formulated in 0.1% DMSO, as used in the original drug screen. Empty PMPC-PDPA polymersomes did not alter physiological measures related to mitochondrial function or induce cytotoxicity. In combination with other techniques such as ligand functionalisation, PMPC-PDPA nanoparticles of well-defined morphology may prove a promising platform for tailoring the pharmacokinetic profile and organ specific bio-distribution of highly hydrophobic compounds

    Induction of renal tumorigenesis with elevated levels of somatic loss of heterozygosity in Tsc1+/- mice on a Blm-deficient background

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    A Bloom’s deficient mouse model (Blmm3/m3) has been shown to induce colorectal tumorigenesis when crossed with Apc+/Min mice. Here, we investigated whether the Blmm3/m3 genotype could induce tumorigenesis in extracolonic tissues in tuberous sclerosis 1–deficient (Tsc1+/) mice that are predisposed to renal cystadenomas and carcinomas. Genotyping of offspring from Tsc1+/ Blm+/m3 intercrosses showed that a f24% excess of Tsc1+/ over Tsc1+/+ mice died before weaning (P = 0.016), although Blm deficiency had no cumulative effect on Tsc1+/ survival. Tsc1+/ Blmm3/m3 mice had significantly more macroscopic and microscopic renal lesions at 3 to 6 months compared with Tsc1+/ Blm+/m3 mice (P =0.0003 and 0.0203, respectively), and their tumors showed significantly increased levels of somatic loss of heterozygosity (LOH) of the wild-type Tsc1 (Tsc1wt) allele compared with those from Tsc1+/ Blm+/+ mice (P < 0.0001). Tsc1+/ Blm+/m3 mice did not show significantly more renal lesions compared with Tsc1+/ Blm+/+ animals; however, their lesions still showed significantly increased levels of somatic LOH of the Tsc1wt allele (P = 0.03). Ninety-five percent (19 of 20) of lesions from Tsc1+/ Blm+/m3 mice retained the wild-type Blm (Blmwt) allele, indicating that the increased somatic LOH at Tsc1 was mediated by Blm haploinsufficiency. Renal lesions from a Blm-deficient background stained positively with anti-phospho-S6 ribosomal protein (Ser240/244), suggesting that these lesions develop through the normal pathway of Tsc-associated tumorigenesis. This work shows the use of the Blmm3/m3 mice for inducing renal tumorigenesis, and the high levels (f87%) of LOH in the resultant tumors will help facilitate mapping of loci involved in tumor progression. (Cancer Res 2005; 65(22): 10179-82

    Identification of six new susceptibility loci for invasive epithelial ovarian cancer.

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