👤 Natalie J Hannan

Neurodegenerative diseases such as Huntington's Disease (HD) have a significant impact on healthcare accessibility and costs. A fatal genetic condition, characterized by the progressive loss of striatal neurons, HD is hindered by the lack of endogenous repair in the adult brain. Recent efforts toward protecting neural circuits through neurotrophic support using brain-derived neurotrophic factor (BDNF) have been suboptimal due to the protein's short half-life and limited diffusion. Addressing this, adeno-associated viral vectors (AAV) can be employed as a delivery tool to spatially transduce cells, enabling the localised production of BDNF with consequential neuron protection and/or plasticity, yet present their own constraints. To overcome these known challenges of AAV gene delivery, an injectable, physiologically stable hydrogel-mimic of the brain's extracellular matrix was fabricated to encapsulate the AAVs. This smart system both shielded and constrained the AAV; optimising transfection and therefore elevated and sustained BDNF presentation at the target site. Here, we achieved high neuroprotection using AAVDJ-BDNF delivered through a hydrogel formed via self-assembling peptide nanoscaffolds. These findings support the notion that the spatiotemporal release of BDNF to striatal neurons, facilitated by engineered biomaterial delivery systems, demonstrates tremendous promise by enhancing the efficacy of gene therapy targeted at slowing neurodegenerative disease progression. Show less

Cell-free RNA (cfRNA) transcripts known to be expressed by the fetal brain are detectable by quantitative reverse transcription PCR (RT-qPCR) in amniotic fluid and represent potential biomarkers of neurodevelopment. The aim of this study was to compare the cfRNA yields from amniotic fluid (AF) collected in a commercial RNA stabilization product with the traditional method of freezing alone. Thirteen women undergoing elective Cesarean birth at term without labor had whole AF collected at the time of uterine incision, prior to membrane rupture. Patient samples were split between Streck RNA blood collection tubes (BCT) and plain sterile polypropylene centrifuge tubes. Cell-free RNA from the AF supernatant was extracted according to a previously published protocol. RT qPCR was performed for the reference gene GAPDH, and three genes associated with neurodevelopment (NRXN3, NTRK3, and ZBTB18). The yield from samples collected in Streck RNA BCT and plain centrifuge tubes were compared with the paired t test. GAPDH, NRXN3 and ZBTB18 amplified successfully in all samples, but NTRK3 did not. The RNA yield was significantly lower in samples collected in the Streck RNA BCT compared with the traditional storage method of freezing alone for all three successfully amplified genes (p < 0.0001). Selected cfRNA neurodevelopment transcripts are consistently detectable in third trimester AF. There appears to be no benefit in collecting AF in Streck RNA BCT for quantitative studies of AF cell-free RNA. Show less

Preeclampsia is a serious pregnancy complication. Soluble endoglin (sEng) is released from the placenta and contributes to the maternal endothelial dysfunction seen in preeclampsia. Recently oxysterols, which activate the Liver X Receptor (LXR), have been implicated in producing sEng, by upregulating matrix metalloproteinase-14 (MMP14; cleaves endoglin to produce sEng) and down-regulating tissue inhibitor of metalloproteinase-3 (TIMP-3; inhibitor of MMP14). The functional experiments in that study were performed on JAR cells (human choriocarcinoma cell line) and placental explants. We characterized LXR in severe preeclamptic placentas, and assessed whether oxysterols increase release of sEng from primary human umbilical vein endothelial cells (HUVECs), primary trophoblasts and placental explants. Given pravastatin is thought to block oxysterol production and inhibit the LXR, we examined whether pravastatin reduces sEng release. LXRα and β were localized to the syncytiotrophoblast and villous tips and were significantly up-regulated in preeclamptic placenta. Oxysterols upregulated sEng production in HUVECs and placental explants although the increases were far more modest than that recently reported. Oxysterols did not upregulate sEng in primary trophoblasts. Furthermore, mRNA expression of MMP14 and TIMP-3 were not altered by oxysterols in any tissue. Surprisingly, pravastatin did not decrease oxysterol-induced upregulation of sEng. LXR is up-regulated in preeclamptic placenta. Oxysterols upregulate sEng production from human tissues, but the increase is modest, suggesting this may not be the main mechanism for the very significant elevations in sEng seen in preeclampsia. Pravastatin does not decrease sEng production. Oxysterols modestly up-regulate sEng production which is not quenched by pravastatin. Show less

Little is known about the degree to which behavioural, biological, and genetic traits contribute to within-person variation in serum cholesterol. Materials and Methods The authors studied within-person variation in serum total and high density lipoprotein (HDL) cholesterol in 458 participants of 27 dietary intervention studies in Wageningen, The Netherlands, from 1976 to 1995. For a median of 4 days between blood draws, the geometric mean of the within-person standard deviation was 0.13 mmol/l ( approximately 5 mg/dl, coefficient of variation = 3.0%) for total cholesterol and 0.04 mmol/l ( approximately 1.5 mg/dl, coefficient of variation = 3.0%) for HDL cholesterol. In mixed-model linear regressions using within-person variance as the dependent variable and including lipid concentration and covariates listed below, within-person variance of both total cholesterol and HDL cholesterol was higher for greater number of days between blood draws and for self-selected diet rather than investigator-controlled diet. Within-person variance of total cholesterol only was higher for non-standardized versus standardized phlebotomy protocol and for female sex. The authors found evidence that the APOA4 -347 (12/22 genotype) and MTP -493 (11 genotype) polymorphisms may increase the within-person variation in total cholesterol. Under certain study design (self-selected diet, use of non-standardized phlebotomy protocol) or participant characteristics (female, certain polymorphisms) within-person lipid variance is increased and required sample size will be greater. These findings may have important implications for the time and cost of such interventions. Show less