Biology subjects

Skinner, A.

Publications and source records attributed to Skinner, A..

5 recordsLinked to original sources

bioRxiv2021

A novel bivalent DNA vaccine encoding both spike protein receptor-binding domain and nucleocapsid protein of SARS-CoV-2 to elicit T cell and neutralising antibody responses that cross react with variants

Although the efficacy of vaccines targeting SARS-CoV-2 is apparent now that the approved mRNA and adenovirus vector vaccines are in widespread use, the longevity of the protective immune response and its efficacy against emerging variants remains to be determined. We have therefore designed a DNA vaccine encoding both the SARS-CoV-2 spike receptorbinding domain ( RBD) and nucleocapsid proteins, the latter of which is highly conserved amongst beta coronaviruses. The vaccine elicits strong pro-inflammatory CD4+ Th1 and CD8+ T-cell responses to both proteins in mice and rats, with responses being significantly enhanced by fusing the nucleocapsid sequence to a modified Fc domain. We have shown that the vaccine also stimulates high titre antibody responses to RBD in mice that efficiently neutralise in pseudotype and live virus neutralisation assays and show cross reactivity with spike proteins from the variants B.1.1.7 (Alpha), B.1.351 (Beta) and B.1.617.2 (Delta). The vaccine also showed good protection in a viral challenge model in ACE2 receptor transgenic mice. This DNA platform can be easily adapted to target variant proteins and we show that a vaccine variant encoding the Beta variant sequence stimulates cross-reactive humoral and T cell responses. These data support the translation of this DNA vaccine platform into the clinic, thereby offering a particular advantage for rapidly targeting emerging SARS-CoV-2 variants.

immunology↗

bioRxiv2020

Translesion Synthesis by MmLV-, AMV-, and HIV-Reverse Transcriptases Using RNA Templates Containing Inosine, Guanosine, and Their 8-oxo-7,8-Dihydropurine Derivatives.

Inosine is ubiquitous and essential in many biological processes, including RNA-editing. In addition, oxidative stress on RNA has been a topic of increasing interest due, in part, to its potential role in the development/progression of disease. In this work we probed the ability of three reverse transcriptases to catalyze the synthesis of cDNA in the presence of RNA templates containing inosine (I), 8-oxo-7,8-dihydroinosine (8oxo-I), guanosine (G), or 8-oxo-7,8-dihydroguanosine (8-oxoG), and explored the impact that these purine derivatives have as a function of position. To this end, we used 29-mers of RNA (as template) containing the modifications at position-18 and reverse transcribed DNA using 17-mers, 18-mers, or 19-mers (as primers). Generally reactivity of the viral RTs, MMLV / AMV / HIV, towards cDNA synthesis was similar for templates containing G or I, as well as for those with 8-oxoG or 8-oxoI. Notable differences are 1) that templates containing I enabled the incorporation of dT when using 17-mers (for exploring incorporation of dNTPs opposite the site of interest); 2) that the use of 18-mers of DNA (to explore cDNA synthesis past the lesion) led to DNA elongation inhibition in the case when a G:dA wobble pair was present, while the presence of I, 8-oxoI, or 8-oxoG led to full synthesis of the corresponding cDNA, with the latter two displaying a more efficient process; 3) that HIV-RT is more sensitive to modified base pairs in the vicinity of cDNA synthesis; and 4) that the presence of a modification two positions away from transcription initiation has an adverse impact on the overall process. Steady-state kinetics were established to determine substrate specificities towards canonical dNTPs (N = G, C, T, A). Overall we found evidence that RNA templates containing inosine are likely to incorporate dC > dT > > dA, where reactivity in the presence of dA was found to be pH dependent (process abolished at pH 7.3); and that the absence of the C2-exocyclic amine, as displayed with templates containing 8-oxoI, leads to increased selectivity towards incorporation of dA over dC. The data will be useful in assessing the impact that the presence of inosine and/or oxidatively generated lesions have on viral processes and adds to previous reports where I codes exclusively like G.

biochemistry↗

bioRxiv2019

O-linked mucin-type glycosylation regulates the transcriptional programme downstream of EGFR in breast cancer

Aberrant mucin type O-linked glycosylation is a common occurrence in cancer. This type of O-linked glycosylation is not limited to mucins but can occur on many cell surface glycoproteins where only a small number of sites may be present. Upon EGF ligation, EGFR induces a signaling cascade but can also translocate to the nucleus where it can directly regulate gene transcription. Here we show that upon EGF binding, human breast cancer cells carrying different O-linked glycans respond by transcribing different gene expression signatures. This is not a result of changes in signal transduction but due to the differential nuclear translocation of EGFR in the two glyco-phenotypes. This is regulated by the formation of an EGFR/galectin-3/MUC1/{beta}-catenin complex at the cell surface that is present in cells carrying short core-1-based O-glycans characteristic of tumour cells but absent in core-2-carrying cells.

cancer biology↗

bioRxiv2017

A Positive Feedback Loop Ensures Propagation of ROS Production and JNK Signaling Throughout Drosophila Tissue Regeneration

Regenerating tissue must initiate the signaling that drives regenerative growth, and sustain that signaling long enough for regeneration to complete. How these key signals are sustained is unclear. To gain a comprehensive view of the changes in gene expression that occur during regeneration, we performed wholegenome mRNAseq of actively regenerating tissue from damaged Drosophila wing imaginal discs. We used genetic tools to ablate the wing primordium to induce regeneration, and carried out transcriptional profiling of the regeneration blastema by fluorescent labeling and sorting the blastema cells, thus identifying differentially expressed genes. Importantly, by using genetic mutants of several of these differentially expressed genes we have confirmed that they have roles in regeneration. Using this approach, we show that high expression of the gene moladietz (mol), which encodes the Duox-maturation factor NIP, is required during regeneration to produce reactive oxygen species (ROS), which in turn sustain JNK signaling during regeneration. We also show that JNK signaling upregulates mol expression, thereby activating a positive feedback signal that ensures the prolonged JNK activation required for regenerative growth. Thus, by wholegenome transcriptional profiling of regenerating tissue we have identified a positive feedback loop that regulates the extent of regenerative growth.\n\nAuthor summaryRegenerating tissue must initiate the signaling that drives regenerative growth, and then sustain that signaling long enough for regeneration to complete. Drosophila imaginal discs, the epithelial structures in the larva that will form the adult animal during metamorphosis, have been an important model system for tissue repair and regeneration for over 60 years. Here we show that damage-induced JNK signaling leads to the upregulation of a gene called moladietz, which encodes a co-factor for an enzyme, NADPH dual oxidase (DUOX), that generates reactive oxygen species (ROS), a key tissue-damage signal. High expression of moladietz induces continuous production of ROS in the regenerating tissue. The sustained production of ROS then continues to activate JNK signaling throughout the course of regeneration, ensuring maximal tissue regrowth.

developmental biology↗

bioRxiv2017

Evaluating Clinical Stop-Smoking Services Globally: Proposal For A Minimum Data Set

Background and aimsBehavioural and pharmacological support for smoking cessation improves the chances of success and represents a highly cost-effective way of preventing chronic disease and premature death. There are a large number of clinical stop-smoking services around the world. These could be connected into a global network to provide data to assess what treatment components are most effective, for what populations, in what settings. This requires data to be collected according to a minimum standard set of data items. This paper sets out a proposal for this global minimum data set.\n\nMethodsWe reviewed sets of data items used in clinical services that have already benefited from standardised approaches to using data. We identified client and treatment data items that may directly or indirectly influence outcome, and outcome variables that were practicable to obtain in clinical practice. We then consulted service providers in countries that may have an interest in taking part in a global network of smoking cessation services, and revised the sets of data items according to their feedback.\n\nResultsThree sets of data items are proposed. The first is a set of features characterising treatments offered by a service. The second is a core set of data items describing clients characteristics, engagement with the service, and outcomes. The third is an extended set of client data items to be captured in addition to the core data items wherever resources permit.\n\nConclusionsWe propose minimum standards for capturing data from clinical smoking cessation services globally. This could provide a basis for meaningful evaluations of different smoking cessation treatments in different populations in a variety of settings across many countries.

epidemiology↗