Development and Application of Synthetic Affinity Ligands for the Purification of Ferritin-Based Influenza Antigens

A recently developed novel recombinant influenza antigen vaccine has shown great success in preclinical studies in ferrets and mice. It provides broader protection, and is efficient to manufacture compared to the conventional trivalent influenza vaccines (TIV). Each strain of the recombinant antigen has a constant self-assembled bacterial ferritin core which, if used as a target for affinity chromatography, could lead to a universal purification method. Ferritin in silico models were used to explore potential target binding sites against ligands synthesized by the four-component Ugi reaction. Two ligands, SJ047 and SJ055, were synthesized in solution, characterized by 1H, 13C, and 2D NMR spectroscopy, and subsequently immobilized on the PEG-functionalized beads. Ligands SJ047 and SJ055 displayed apparent Kd values of 2.04 × 10–7 M and 1.91 × 10–8 M, respectively, against the ferritin. SJ047 and SJ055-functionalized resins were able to purify hemagglutinin (New Caledonia)-ferritin expressed in a crude Human Embryonic Kidney (HEK) cell supernatant in a single step to a purity of 85 ± 0.5% (97 ± 1% yield) and 87.5 ± 0.5% (95.5 ± 1.5% yield), respectively. Additionally, SJ047 and SJ055-functionalized resins purified the recombinant antigens when spiked at known concentrations into HEK supernatants. All three strains, hemagglutinin (New Caledonia)-ferritin, hemagglutinin (California)-ferritin, and hemagglutinin (Singapore)-ferritin were purified, thereby offering an ideal alternate platform for affinity chromatography. Following elution from the affinity adsorbents, absorbance at 350 nm showed that there was no aggregation of the recombinant antigens and dynamic light scattering studies further confirmed the structural integrity of the recombinant antigen. The use of Ugi ligands coupled to a PEG-spacer arm to target the ferritin core of the strain is entirely novel and provides an efficient purification of these recombinant antigens. This approach represents a potentially universal method to purify any ferritin-based vaccine

Contribution of Saudi Neurosurgeons to the International Neurosurgical Literature: a Bibliometric Analysis of Trends Over the Last Three Decades

This review is a bibliometric analysis of the contribution of neurosurgeons from the Kingdom of Saudi Arabia (KSA) to the international neurosurgical literature over the last three decades. The study aimed at determining changes in publication trends over time and assessing the impact of these changes on citation numbers. All publications in the PubMed-indexed neurosurgical journals that were authored by at least one Saudi neurosurgeon were selected. The articles were divided into two study groups according to publication year whether during the last decade (2011- 2020) or the previous two decades (1991- 2010). Changes in publication trends were determined by comparing the bibliometric characteristics of the articles in both groups. The impact of the changes on citation numbers was assessed by correlating the annual citation rates for the articles with their bibliometric qualities. A total of 352 publications were suitable for the review (200 articles published during 2011- 2020, and 152 during 1991- 2010). Temporal changes in the publishing journals and first authors’ centres and regions were observed. The articles that were published in the last decade were associated with a significantly higher annual publication rate, a greater number of authors, centres, and countries, and a larger sample size compared to those published in the previous two decades. They also had a lower percentage of Saudi total and first authorship as well as a smaller proportion of case reports. The annual citation rate was significantly impacted by the duration from publication, sample size, and study type during both study periods. However, only during the last decade, the annual citation rate was positively influenced by the journal’s impact factor, number of authors, centres, countries, and percentage of Saudi authorship. We conclude that KSA neurosurgeons’ contribution to international neurosurgical journals had increased considerably over the last decade. The publications were authored by neurosurgeons from a wider range of centres and regions than in the past. A bigger portion of publications had become more multi-authored, multi-centred, and multi-national as well as reported larger sample sizes and lesser rates of case reports. The changes in publication trends correlated positively with the articles’ annual citation rates. The findings could be considered encouraging

Bespoke affinity ligands for the purification of therapeutic proteins

This article provides an overview of the current challenges and trends in bioprocessing, with a focus on recent advances in the affinity purification of the principal classes of biotherapeutics, including monoclonal antibodies, glycoproteins, vaccines and erythropoietin. Affinity chromatography is usually applied during large-scale protein purification; it involves affinity ligands of biological or synthetic origin. The high productivity that is currently achieved during upstream processing is placing an increasing burden on the downstream production phase which suffers from limited capacities. Consequently, while genetic engineering is helping to increase the stability and capacity of natural ligands, in silico approaches combined with combinatorial chemistry may be used to implement economical purification strategies based on synthetic ligands for the improvement of downstream processing and biomanufacturing

Targeting allosteric sites of human aromatase: a comprehensive in-silico and in-vitro workflow to find potential plant-based anti-breast cancer therapeutics

Recent findings suggested several allosteric pockets on human aromatase that could be utilised for the development of new modulators able to inhibit this enzyme in a new mechanism. Herein, we applied an integrated in-silico-based approach supported by in-vitro enzyme-based and cell-based validation assays to select the best leads able to target these allosteric binding sites from a small library of plant-derived natural products. Chrysin, apigenin, and resveratrol were found to be the best inhibitors targeting the enzyme’s substrate access channel and were able to produce a competitive inhibition with IC50 values ranged from 1.7 to 15.8 µM. Moreover, they showed a more potent antiproliferative effect against ER+ (MCF-7) than ER- one (MDA-MB-231) cell lines. On the other hand, both pomiferin and berberine were the best hits for the enzyme’s haem-proximal cavity producing a non-competitive inhibition (IC50 15.1 and 21.4 µM, respectively) and showed selective antiproliferative activity towards MCF-7 cell lines