Restriction of HIV-1 Replication in Monocytes Is Abolished by Vpx of SIVsmmPBj

Background: Human primary monocytes are refractory to infection with the human immunodeficiency virus 1 (HIV-1) or transduction with HIV-1-derived vectors. In contrast, efficient single round transduction of monocytes is mediated by vectors derived from simian immunodeficiency virus of sooty mangabeys (SIVsmmPBj), depending on the presence of the viral accessory protein Vpx. Methods and Findings: Here we analyzed whether Vpx of SIVsmmPBj is sufficient for transduction of primary monocytes by HIV-1-derived vectors. To enable incorporation of PBj Vpx into HIV-1 vector particles, a HA-Vpr/Vpx fusion protein was generated. Supplementation of HIV-1 vector particles with this fusion protein was not sufficient to facilitate transduction of human monocytes. However, monocyte transduction with HIV-1-derived vectors was significantly enhanced after delivery of Vpx proteins by virus-like particles (VLPs) derived from SIVsmmPBj. Moreover, pre-incubation with Vpx-containing VLPs restored replication capacity of infectious HIV-1 in human monocytes. In monocytes of non-human primates, single-round transduction with HIV-1 vectors was enabled. Conclusion: Vpx enhances transduction of primary human and even non-human monocytes with HIV-1-derived vectors, only if delivered in the background of SIVsmmPBj-derived virus-like particles. Thus, for accurate Vpx function the presence of SIVsmmPBj capsid proteins might be required. Vpx is essential to overcome a block of early infection steps in primary monocytes

Atomic force microscopy on chromosomes, chromatin and DNA: A review

Strappe, P ORCiD: 0000-0003-0100-0558The purpose of this review is to discuss the achievements and progress that has been made in the use of atomic force microscopy in DNA related research in the last 25 years. For this review DNA related research is split up in chromosomal-, chromatin- and DNA focused research to achieve a logical flow from large- to smaller structures. The focus of this review is not only on the AFM as imaging tool but also on the AFM as measuring tool using force spectroscopy, as therein lays its greatest advantage and future. The amazing technological and experimental progress that has been made during the last 25 years is too extensive to fully cover in this review but some key developments and experiments have been described to give an overview of the evolution of AFM use from 'imaging tool' to 'measurement tool' on chromosomes, chromatin and DNA. © 2012

Gene modification of mesenchymal stem cells and articular chondrocytes to enhance chondrogenesis

Strappe, P ORCiD: 0000-0003-0100-0558Current cell based treatment for articular cartilage and osteochondral defects are hampered by issues such as cellular dedifferentiation and hypertrophy of the resident or transplanted cells. The reduced expression of chondrogenic signalling molecules and transcription factors is a major contributing factor to changes in cell phenotype. Gene modification of chondrocytes may be one approach to redirect cells to their primary phenotype and recent advances in nonviral and viral gene delivery technologies have enabled the expression of these lost factors at high efficiency and specificity to regain chondrocyte function. This review focuses on the various candidate genes that encode signalling molecules and transcription factors that are specific for the enhancement of the chondrogenic phenotype and also how epigenetic regulators of chondrogenesis in the form of microRNA may also play an important role. © 2014 Saliya Gurusinghe and Padraig Strappe

A comparison of RS4-type resistant starch to RS2-type resistant starch in suppressing oxidative stress in high-fat-diet-induced obese rats

The anti-obesity effects of two types of resistant starch (RS) in high-fat-diet-induced obese rats were investigated. The serum triglycerides, total cholesterol and malondialdehyde concentrations were significantly reduced, and the total antioxidant capacity, superoxide dismutase levels and glutathione peroxidase activity were increased by RS2 and RS4 consumption compared to the obesity group. A significant reduction in the serum glucose level and elevations in hepatic lipid metabolic enzyme activities were observed only for RS4 administration. Moreover, the expression levels of the fatty acid synthesis associated genes ACC and Fads1, the triglyceride synthesis and metabolism-related gene SREBP-1, the adipocyte differentiation gene PPARγ, the cholesterol synthesis associated gene HMGCR, and the gluconeogenesis associated gene GAPDH were all significantly down-regulated, whilst the lipid oxidation gene Acox1 and the liver function genes Gsta2, Nqo1, and Gclm were up-regulated in both administered groups. Additionally, RS4 performed well in up-regulating the expressions of Gsta2, Gsta3, Nqo1, and Egfr, and down-regulating LXRα, Igfbp1, and PML. RS4 exhibited great advantages in reducing oxidative stress compared with RS2.Associated Grant:Agricultural Science and Technology Achievements Transformation Fund (2014GB2A100527), the National Key Research and Development Program (2016YFD0400100), the NSFC (no. 31471701), the NSFC (U1501214), the Tianjin Research Program of Application Foundation and Advanced Technology (15JCZDJC34300), and the China–European research collaboration programme (SQ2013ZOA100001

Endothelial progenitor cells and pulmonary arterial hypertension

Strappe, P ORCiD: 0000-0003-0100-0558Pulmonary arterial hypertension (PAH) is a progressive disease characterised by lung endothelial cell dysfunction and vascular remodelling. A number of studies now suggest that endothelial progenitor cells (EPCs) may induce neovascularisation and could be a promising approach for cell based therapy for PAH. On the contrary EPCs may contribute to pulmonary vascular remodelling, particularly in end-stage pulmonary disease. This review article will provide a brief summary of the relationship between PAH and EPCs, the application of the EPCs to PAH and highlight the potential clinical application of the EPCs cell therapy to PAH. © 2014.Associated Grant:National Natural Science Foundation of China (No. 81270104

Splice variants of the Alzheimer's disease beta-secretase, BACE1

Strappe, P ORCiD: 0000-0003-0100-0558Cleavage of the amyloid precursor protein by enzymes commonly referred to as β- and γ-secretase constitute an important process in the pathogenesis of Alzheimer's disease (AD). The regulation of this process is therefore an important subject of investigation. Numerous sources of endogenous regulation have been identified, and one of these is the relative abundance and regulation of splice variants of the β-secretase, BACE1 (β-site amyloid precursor protein cleaving enzyme 1). In this review, we will briefly discuss the main characteristics of BACE1, review the different variants of this enzyme that have been identified to date, and highlight their possible implication in AD. © 2012 Springer-Verlag Berlin Heidelberg.Associated Grant Code:57039

Efficient transduction of equine adipose-derived mesenchymal stem cells by VSV-G pseudotyped lentiviral vectors

Strappe, P ORCiD: 0000-0003-0100-0558Equine adipose-derived mesenchymal stem cells (EADMSC) provide a unique cell-based approach for treatment of a variety of equine musculoskeletal injuries, via regeneration of diseased or damaged tissue, or the secretion of immunomodulatory molecules. These capabilities can be further enhanced by genetic modification using lentiviral vectors, which provide a safe and efficient method of gene delivery. We investigated the suitability of lentiviral vector technology for gene delivery into EADMSC, using GFP expressing lentiviral vectors pseudotyped with the G glycoprotein from the vesicular stomatitis virus (V-GFP) or, for the first time, the baculovirus gp64 envelope protein (G-GFP). In this study, we produced similarly high titre V-GFP and G-GFP lentiviral vectors. Flow cytometric analysis showed efficient transduction using V-GFP; however G-GFP exhibited a poor ability to transduce EADMSC. Transduction resulted in sustained GFP expression over four passages, with minimal effects on cell viability and doubling time, and an unaltered chondrogenic differentiation potential.Associated Grant:Australian Government’s Australian Post-Graduate Award (PhD scholarship awarded to G. Petersen

The potential role of p53 and MAPK pathways in the hepatotoxicity of deep-fried oil and in resistant starch-induced protection

In this study, rats with a fresh oil diet, a deep-fried oil diet, and a deep-fried oil and resistant starch (RS) diet were investigated for revealing the effects of deep-fried oil to the metabolic system and if RS could effectively attenuate metabolic dysfunction caused by deep-fried oil. The results showed that DO feeding led to significant increases of liver biomarkers of alanine aminotransferase (ALT) and aspartate transaminase (AST), accompanied by consistent reduction of total antioxidation (T-AOC) and glutathione peroxidase (GSH-Px) activity compared to the rats feeding with unheated canola oil (FO group) (p<0.05). Liver histology of rats in DO group exhibited membrane blebbing and boundary ambiguity, indicating DO might exert significant hepatotoxic effects. However, RS intervention (DO-RS group) significantly reversed these changes. Furthermore, the results in this study revealed that p53 and MAPK signaling pathways presented in the significantly enriched KEGG pathways list in FO versus DO group, but not in FO versus DO-RS group, suggesting RS intervention modulated these two signaling pathways. This is the first study to investigate RS intervention on the attenuation of hepatotoxicity induced by DO intake in the dietary. Practical applications: This study investigates the toxic effects of deep-fried oil consumption on health, in particular on hepatic immune system and the related mechanisms involved in this process. The main target of this research work is to contribute with useful information of deep-fried oil intake to the food industry and to find out effective ways to ameliorate the risk of deep-fried oil diet. A deep-fried oil diet can cause hepatotoxicity; in contrast, rats fed a deep-fried oil and RS diet are protected. The modulation of p53 and MAPK pathways might be one of the key regulations for RS intervention to attenuate liver dysfunction biomarkers (ALT and AST).Associated Grant:Australian Research Council-Industrial Transformation Training Centre for Functional Grains, Charles Sturt University