The In-Vivo Use of Superparamagnetic Iron Oxide Nanoparticles to Detect Inflammation Elicits a Cytokine Response but Does Not Aggravate Experimental Arthritis

BackgroundSuperparamagnetic Iron Oxide Nanoparticles (SPION) are used in diagnostic imaging of a variety of different diseases. For such in-vivo application, an additional coating with a polymer, for example polyvinyl alcohol (PVA), is needed to stabilize the SPION and prevent aggregation. As the particles are foreign to the body, reaction against the SPION could occur. In this study we investigated the effects that SPION may have on experimental arthritis after intra-articular (i.a.) or intravenous (i.v.) injection.MethodsPVA-coated SPION were injected either i.a. (6 or 24 μg iron) or i.v. (100 μg or 1 mg iron) into naïve Toll-like receptor-4 deficient (TLR4-/-) or wild-type C57Bl/6 mice, or C57Bl/6 mice with antigen-induced arthritis. As control, some mice were injected with PVA or PBS. MR imaging was performed at 1 and 7 days after injection. Mice were sacrificed 2 hours and 1, 2, 7, 10 and 14 days after injection of the SPION, and RNA from synovium and liver was isolated for pro-inflammatory gene expression analysis. Serum cytokine measurements and whole knee joint histology were also performed.ResultsInjection of a high dose of SPION or PVA into naïve knee joints resulted in an immediate upregulation of pro-inflammatory gene expression in the synovium. A similar gene expression profile was observed after SPION or PVA injection into knee joints of TLR4-/- mice, indicating that this effect is not due to LPS contamination. Histological analysis of the knee joints also revealed synovial inflammation after SPION injection. Two hours after i.v. injection of SPION or PVA into naïve mice, an upregulation of pro-inflammatory gene expression was detected in the liver. Administration of SPION or PVA into arthritic mice via i.a. injection did not result in an upregulation in gene expression and also no additional effects were observed on histology. MR imaging and histology showed long-term retention of SPION in the inflamed joint. However, 14 days after the injections no long-term effects were evident for gene expression, histology or serum cytokine concentrations.ConclusionsInjection of SPION, either locally or systemically, gives an acute inflammatory response. In the long term, up to 14 days after the injection, while the SPION reside in the joint, no further activating effects of SPION were observed. Hence, we conclude that SPION do not aggravate arthritis and can therefore be used safely to detect joint inflammation by MR imaging.     

Factors Influencing Antiretroviral Adherence and Virological Outcomes in People Living with HIV in the Highlands of Papua New Guinea

Adherence to antiretroviral therapy (ART) is paramount for virological suppression and positive treatment outcomes. ART has been rapidly scaled up in Papua New Guinea (PNG) in recent years, however clinical monitoring of HIV+ individuals on ART is limited. A cross-sectional study was conducted at two major sexual health clinics in high HIV prevalence provinces in the Highlands Region of PNG to assess ART adherence, factors affecting adherence and the relationship between ART adherence and virological outcomes. Ninety-five HIV+ individuals were recruited and administered a questionnaire to gather demographic and ART adherence information whilst clinical data and pill counts were extracted from patient charts and blood was collected for viral load testing. Bivariate analysis was performed to identify independent predictors of ART adherence. Fourteen percent (n = 12) of participants showed evidence of virological failure. Although the majority of participants self-reported excellent ART adherence in the last seven days (78.9%, 75/91), pill count measurements indicated only 40% (34/84) with >95% adherence in the last month. Taking other medications while on ART (p = 0.01) and taking ART for ≥1 year (p = 0.037) were positively associated with adherence by self-report and pill count, respectively. Participants who had never heard of drug resistance were more likely to show virological failure (p = 0.033). Misconception on routes of HIV transmission still persists in the studied population. These findings indicate that non-adherence to ART is high in this region of PNG and continued education and strategies to improve adherence are required to ensure the efficacy of ART and prevent HIV drug resistance.     

Induction of Neuronal Morphology in the 661W Cone Photoreceptor Cell Line with Staurosporine

Purpose

RGC-5 cells undergo differentiation into a neuronal phenotype with low concentrations of staurosporine. Although the RGC-5 cell line was initially thought to be of retinal ganglion cell origin, recent evidence suggests that the RGC-5 line could have been the result of contamination with 661W mouse cone photoreceptor cells. This raised the possibility that a cone photoreceptor cell line could be multipotent and could be differentiated to a neuronal phenotype.

Methods

661W and RGC-5 cells, non-neuronal retinal astrocytes, retinal endothelial cells, retinal pericytes, M21 melanoma cells, K562 chronic myelogenous leukemia cells, and Daudi Burkitt lymphoma cells, were differentiated with staurosporine. The resulting morphology was quantitated using NeuronJ with respect to neurite counts and topology.

Results

Treatment with staurosporine induced similar-appearing morphological differentiation in both 661W and RGC-5 cells. The following measures were not significantly different between 661W and RGC-5 cells: number of neurites per cell, total neurite field length, number of neurite branch points, and cell viability. Neuronal-like differentiation was not observed in the other cell lines tested.

Conclusions

661W and RGC-5 cells have virtually identical and distinctive morphology when differentiated with low concentrations of staurosporine. This result demonstrates that a retinal neuronal precursor cell with cone photoreceptor lineage can be differentiated to express a neuronal morphology.     

Partial protein domains: evolutionary insights and bioinformatics challenges

Protein domains are generally thought to correspond to units of evolution. New research raises questions about how such domains are defined with bioinformatics tools and sheds light on how evolution has enabled partial domains to be viable.With the rapid expansion in the number of determined protein sequences - over 92 million in UniProt in March 2015 - an ever-increasing number of biologists are using bioinformatics tools for annotation of these sequences. One widely used strategy is to identify occurrences of Pfam families within the sequence of interest [1]. A Pfam family is a multiple sequence alignment of the occurrences of a particular domain both in different species and in different regions of the same protein. The concept underpinning Pfam is that proteins typically comprise one or more domains (regions), each of which is an evolutionary unit that generally has a well-defined biological function. A significant sequence similarity between a query protein and a Pfam family provides the basis for annotations. Two recent articles [2,3] in Genome Biology evaluate the implications of having the query sequence only matching part of a Pfam family, which is an intriguing finding, given that a Pfam family is considered to be an evolutionary unit.     

The RNA helicase,eIF4A‐1, is required for ovule development and cell size homeostasis in Arabidopsis

eIF4A is a highly conserved RNA‐stimulated ATPase and helicase involved in the initiation of mRNA translation. The Arabidopsis genome encodes two isoforms, one of which (eIF4A‐1) is required for the coordination between cell cycle progression and cell size. A T‐DNA mutant eif4a1 line, with reduced eIF4A protein levels, displays slow growth, reduced lateral root formation, delayed flowering and abnormal ovule development. Loss of eIF4A‐1 reduces the proportion of mitotic cells in the root meristem and perturbs the relationship between cell size and cell cycle progression. Several cell cycle reporter proteins, particularly those expressed at G2/M, have reduced expression in eif4a1 mutant meristems. Single eif4a1 mutants are semisterile and show aberrant ovule growth, whereas double eif4a1 eif4a2 homozygous mutants could not be recovered, indicating that eIF4A function is essential for plant growth and development.