Biology subjects

Schots, A.

Publications and source records attributed to Schots, A..

5 recordsLinked to original sources

bioRxiv2025

Precision Glycoform Engineering: Combining plant and in vitro systems for tailored biopharmaceutical production

Protein biopharmaceuticals play a key role in providing effective, targeted, and personalized therapies for diverse diseases, while also preventing and mitigating a broad range of infections. N-glycosylation is a key post-translational modification influencing the biological activity of many protein-based therapeutics, yet structure-function relationships of N-glycans remain poorly understood due to challenges in producing homogeneous glycoforms. Current go-to production hosts, mammalian and yeast cells, often yield heterogeneous glycan profiles and require extensive genetic manipulation. Alternative production hosts such as the plant Nicotiana benthamiana, provide more homogeneous glycosylation and flexibility through transient expression, but are limited in the generation of certain glycoforms. In vitro glycoengineering can overcome these limitations but is time consuming and requires expensive resources. In this study, we show that by combining in planta and in vitro glycoengineering strategies, we can quickly produce a wide range of homogeneous glycoforms of pharmaceutical proteins with high mannose, paucimannose, hybrid and complex N-glycan structures. Using N. benthamiana as a transient expression host, we produced two pharmaceutical glycoproteins -- the monoclonal antibody rituximab and the helminth vaccine candidate OoASP-1 -- and modified them in vitro using Escherichia coli produced glycoenzymes. The combination of these two glycoengineering systems minimizes the amount of time and resources required, while maintaining high glycan homogeneity. This scalable, flexible, and cost-effective platform opens the door to glycan structure-function relationship studies and can support rational design of next-generation biopharmaceuticals.

bioengineering↗

bioRxiv2025

Le click c'est chic: a plug-and-play virus-like particle vaccination platform enabled by non-canonical amino acid incorporation and click chemistry in the tobacco BY-2 cell-free protein synthesis system

Non-canonical amino acids (ncaas) can provide recombinant proteins with novel exciting functionalities beyond the limits of nature, such as orthogonal reaction groups. Notably, ncaa introduction can be used in vaccinology to enhance the adaptability and immunogenicity of putative vaccine candidates. Cell-free protein synthesis (CFPS) represents the most promising methodology to introduce ncaa into recombinant proteins of interest. However, traditionally used prokaryotic CFPS systems show limitations to produce complex proteins requiring post-translational modifications, whilst eukaryotic CFPS systems have historically been difficult to scale and show low protein yields. In this work, we establish the site-specific introduction of ncaas into complex proteins with the high-yielding and scalable eukaryotic tobacco BY-2 CFPS system (BYL), commercialised as ALiCE(R). The tyrosine transferase from Escherichia coli (eTyrT) was tested for amber suppression-mediated ncaa incorporation in BYL. eTyrT showed high incorporation yields of up to 2mg/ml recombinant protein for the azido-tyrosine and alkyne-tyrosine ncaas, with linear scalability up to 10ml without any losses in protein yield. We applied ncaa incorporation in BYL to enable click chemistry bioconjugation of the receptor binding domain (RBD) of influenza hemagglutinin to pre-assembled hepatitis B core (HBc) virus-like particles (VLPs). BYL efficiently produced the alkyne-modified RBD and azido-modified HBc VLPs, and their conjugation via copper-catalysed azide-alkyne cycloaddition (CuAAC) led to structurally intact, RBD-coated particles. VLP-RBD conjugates could efficiently hemagglutinate chicken erythrocytes where the individual proteins could not, proving both the sialic-acid binding activity of the RBD and its multivalent presentation by the HBc VLP. Finally, when used to vaccinate mice the conjugated RBD-VLPs showed a greater protection against live influenza challenge than free RBD. This research thus enables ncaa introduction for recombinant proteins produced in BYL, constructing a novel plug-and-play vaccine platform and further expanding the capabilities of BYL to produce vaccine candidates and other proteins of interest.

molecular biology↗

bioRxiv2020

Conserved codon adaptation in highly expressed genes is associated with higher regularity in mRNA secondary structures

The redundancy of the genetic code allows for a regulatory layer to optimize protein synthesis by modulating translation and degradation of mRNAs. Patterns in synonymous codon usage in highly expressed genes have been studied in many species, but scarcely in conjunction with mRNA secondary structure. Here, we analyzed over 2,000 expression profiles covering a range of strains, treatments, and developmental stages of five model species (Escherichia coli, Arabidopsis thaliana, Saccharomyces cerevisiae, Caenorhabditis elegans, and Mus musculus). By comparative analyses of genes constitutively expressed at high and low levels, we revealed a conserved shift in codon usage and predicted mRNA secondary structures. Highly abundant transcripts and proteins, as well as high protein per transcript ratios, were consistently associated with less variable and shorter stretches of weak mRNA secondary structures (loops). Genome-wide recoding showed that codons with the highest relative increase in highly expressed genes, often C-ending and not necessarily the most frequent, enhanced formation of uniform loop sizes. Our results point at a general selective force contributing to the optimal expression of abundant proteins as less variable secondary structures promote regular ribosome trafficking with less detrimental collisions, thereby leading to an increase in mRNA stability and a higher translation efficiency.

bioinformatics↗

bioRxiv2020

The helminth glycoprotein omega-1 improves metabolic homeostasis in obese mice through type-2 immunity-independent inhibition of food intake

Type 2 immunity plays an essential role in the maintenance of metabolic homeostasis and its disruption during obesity promotes meta-inflammation and insulin resistance. Infection with the helminth parasite Schistosoma mansoni and treatment with its soluble egg antigens (SEA) can induce a type 2 immune response in metabolic organs and improve insulin sensitivity and glucose tolerance in obese mice, yet a causal relationship remains unproven. Here, we investigated the effects and underlying mechanisms of the T2 ribonuclease omega-1 (ω1), one of the major S. mansoni immunomodulatory glycoproteins, on metabolic homeostasis. Male C57Bl6/J mice were fed a high-fat diet for 12 weeks followed by bi-weekly injection of SEA, ω1 or vehicle for 4 additional weeks. Whole-body metabolic homeostasis and energy expenditure were assessed by glucose/insulin tolerance tests and indirect calorimetry, respectively. Tissue-specific immune cell phenotypes were determined by flow cytometry. We show that treatment of obese mice with plant-produced recombinant ω1, harboring similar glycan motifs as present on the native molecule, decreased body fat mass and improved systemic insulin sensitivity and glucose tolerance in a time-and dose-dependent manner. This effect was associated with an increase in white adipose tissue (WAT) type 2 T helper cells, eosinophils and alternatively-activated macrophages, without affecting type 2 innate lymphoid cells. In contrast to SEA, the metabolic effects of ω1 were still observed in obese STAT6-deficient mice with impaired type 2 immunity, indicating that its metabolic effects are independent of the type 2 immune response. Instead, we found that ω1 inhibited food intake, without affecting locomotor activity, WAT thermogenic capacity or whole-body energy expenditure, an effect also occurring in leptin receptor-deficient obese and hyperphagic db/db mice. Altogether, we demonstrate that while the helminth glycoprotein ω1 can induce type 2 immunity, it improves whole-body metabolic homeostasis in obese mice by inhibiting food intake via a STAT6-independent mechanism.Author summary The obesity-induced chronic low-grade inflammation, notably in adipose tissue, contributes to insulin resistance and increased risk of type 2 diabetes. We have previously shown that infection with parasitic helminth worms was associated with protection against obesity-related metabolic dysfunctions both in mice and humans. We have also reported that treatment of obese mice with an extract of Schistosoma mansoni eggs (SEA) improves insulin sensitivity and glucose tolerance, a beneficial effect that was associated with a helminth-specific type 2 immune response in metabolic organs. Here, we studied the effects of omega-1 (ω1), a single immunomodulatory molecule from SEA, on metabolic health in obese mice, and investigated the role of the host immune response elicited. We found that ω1 induced a helminth-characteristic type 2 immune response in adipose tissue and improved both insulin sensitivity and glucose tolerance in obese mice. Yet, in contrast to SEA, ω1’s immunomodulatory properties were dispensable for its metabolic effects. Instead, we show that ω1 inhibited food intake, a feature accounting for most of the improvements in metabolic health. Together, our findings indicate that helminth molecules may improve metabolic health through multiple distinct mechanisms, and further characterization of such molecules could lead to new therapeutic strategies to combat obesity.List of abbreviationsAAMAlternatively activated macrophageALATAlanine aminotransferaseBATBrown adipose tissueDCDendritic cellEEEnergy expenditureGTTGlucose tolerance testHEKHuman embryonic kidneyHFDHigh-fat dietHOMA-IRHomeostatic model assessment of insulin resistanceIFN-γInterferon gammaILInterleukinILCInnate lymphoid cellITTInsulin tolerance testLBMLean body massLFDLow-fat dietNAFLDNon-alcoholic fatty liver diseaseNASHNon-alcoholic steatohepatitispLeX-ω1Recombinant omega-1 from LeX-glyco-engineered Nicotiana benthamiana plantsPMAPhorbol myristate acetatepWT-ω1Recombinant omega-1 from wild-type N. benthamiana plantsSEASchistosoma mansoni soluble egg antigensSTATSignal transducer and activator of transcriptionSVFStromal vascular fractionThT helperTNFTumor necrosis factorUCP1Uncoupling protein 1WATWhite adipose tissueWTWild-typeView Full Text

immunology↗

bioRxiv2017

GM-CSF negatively regulates early IL-10 mediated responses

Inflammatory disorders are becoming more prevalent in the Western world. Treatment of these diseases relies on the intervention in inflammatory responses thereby restoring immune homeostasis. One cytokine that has the potential to restore immune homeostasis is the anti-inflammatory cytokine interleukin-10 (IL-10). But until now IL-10 treatment has not been as successful as anticipated. A reason for this may be that IL-10 responsiveness depends on the environment of the inflamed tissue. In this study we describe that granulocyte-macrophage colony-stimulating factor (GM-CSF) is a key cytokine that negatively regulates IL-10-mediated responses. Dendritic cells differentiated from bone marrow with GM-CSF have a reduced ability to respond to IL-10. Dendritic cells are impaired in their up-regulation of IL-10-induced SOCS3 expression and are unable to suppress LPS-induced TNF- expression at an early time point. Furthermore, GM-CSF treatment partially replicates this phenotype in macrophages. Surprisingly, GM-CSF seems to regulate IL-10 activity in macrophages without affecting STAT3 activation. Still, GM-CSF induces constitutive phosphorylation of glycogen synthase kinase 3{beta}, a signalling component downstream of the PI3K/Akt pathway. Knowledge on the exact mechanism by which GM-CSF negatively regulates IL-10 activity could give novel insights on the integration of signal transduction pathways elicited by different cytokines. Ultimately this knowledge could provide us with new therapeutic strategies to treat inflammatory disorders.

immunology↗