Community-Wide Experimental Evaluation of the PROSS Stability-Design Method

Recent years have seen a dramatic improvement in protein-design methodology. Nevertheless, most methods demand expert intervention, limiting their widespread adoption. By contrast, the PROSS algorithm for improving protein stability and heterologous expression levels has been successfully applied to a range of challenging enzymes and binding proteins. Here, we benchmark the application of PROSS as a stand-alone tool for protein scientists with no or limited experience in modeling. Twelve laboratories from the Protein Production and Purification Partnership in Europe (P4EU) challenged the PROSS algorithm with 14 unrelated protein targets without support from the PROSS developers. For each target, up to six designs were evaluated for expression levels and in some cases, for thermal stability and activity. In nine targets, designs exhibited increased heterologous expression levels either in prokaryotic and/or eukaryotic expression systems under experimental conditions that were tailored for each target protein. Furthermore, we observed increased thermal stability in nine of ten tested targets. In two prime examples, the human Stem Cell Factor (hSCF) and human Cadherin-Like Domain (CLD12) from the RET receptor, the wild type proteins were not expressible as soluble proteins in E. coli, yet the PROSS designs exhibited high expression levels in E. coli and HEK293 cells, respectively, and improved thermal stability. We conclude that PROSS may improve stability and expressibility in diverse cases, and that improvement typically requires target-specific expression conditions. This study demonstrates the strengths of community-wide efforts to probe the generality of new methods and recommends areas for future research to advance practically useful algorithms for protein science.

Tagging Proteins with Fluorescent Reporters Using the CRISPR/Cas9 System and Double-Stranded DNA Donors

Macromolecular complexes govern the majority of biological processes and are of great biomedical relevance as factors that perturb interaction networks underlie a number of diseases, and inhibition of protein-protein interactions is a common strategy in drug discovery. Genome editing technologies enable precise modifications in protein coding genes in mammalian cells, offering the possibility to introduce affinity tags or fluorescent reporters for proteomic or imaging applications in the bona fide cellular context. Here we describe a streamlined procedure which uses the CRISPR/Cas9 system and a double-stranded donor plasmid for efficient generation of homozygous endogenously GFP-tagged human cell lines. Establishing cellular models that preserve native genomic regulation of the target protein is instrumental to investigate protein localization and dynamics using fluorescence imaging but also to affinity purify associated protein complexes using anti-GFP antibodies or nanobodies.

MACVIA-LR (Fighting Chronic Diseases for Active and Healthy Ageing in Languedoc-Roussillon): A Success Story of the European Innovation Partnership on Active and Healthy Ageing

The Région Languedoc Roussillon is the umbrella organisation for an interconnected and integrated project on active and healthy ageing (AHA). It covers the 3 pillars of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA): (A) Prevention and health promotion, (B) Care and cure, (C) and (D) Active and independent living of elderly people. All sub-activities (poly-pharmacy, falls prevention initiative, prevention of frailty, chronic respiratory diseases, chronic diseases with multimorbidities, chronic infectious diseases, active and independent living and disability) have been included in MACVIA-LR which has a strong political commitment and involves all stakeholders (public, private, patients, policy makers) including CARSAT-LR and the Eurobiomed cluster. It is a Reference Site of the EIP on AHA. The framework of MACVIA-LR has the vision that the prevention and management of chronic diseases is essential for the promotion of AHA and for the reduction of handicap. The main objectives of MACVIA-LR are: (i) to develop innovative solutions for a network of Living labs in order to reduce avoidable hospitalisations and loss of autonomy while improving quality of life, (ii) to disseminate the innovation. The three years of MACVIA-LR activities are reported in this paper.

Developmental determinants in non-communicable chronic diseases and ageing

Prenatal and peri-natal events play a fundamental role in health, development of diseases and ageing (Developmental Origins of Health and Disease (DOHaD)). Research on the determinants of active and healthy ageing is a priority to: (i) inform strategies for reducing societal and individual costs of an ageing population and (ii) develop effective novel prevention strategies. It is important to compare the trajectories of respiratory diseases with those of other chronic diseases.

Polymorphism at the avpr1a locus in male prairie voles correlated with genetic but not social monogamy in field populations

Integrative studies of genetics, neurobiology and behaviour indicate that polymorphism in specific genes contributes to variation observed in some complex social behaviours. The neuropeptide arginine vasopressin plays an important role in the regulation of a variety of social behaviours, including social attachment of males to females, through its action on the vasopressin 1a receptor (V1aR). In socially monogamous prairie voles (Microtus ochrogaster), polymorphism in the length of microsatellite DNA within the regulatory region of the gene (avpr1a) encoding the V1aR predicts differences among males in neural expression of V1aRs and partner preference under laboratory conditions. However, understanding the extent to which V1aR mediates variation in prairie vole social and reproductive behaviour observed in nature requires investigating the consequences of avpr1a polymorphism and environmental influences under ecologically relevant conditions. We examined the relationship between avpr1a length polymorphism and monogamy among male prairie voles living in 0.1 ha enclosures during a time similar to their natural lifespan. We found no evidence that avpr1a genotype of males predicts variation in social monogamy measured in the field but some indices of social monogamy were affected by population density. Parentage data indicated that a male's avpr1a genotype significantly influenced the number of females with which he sired offspring and the total number of offspring sired. Total brain concentrations of V1aR mRNA were not associated with either male behaviour or avpr1a genotype. These data show that melding ecological field studies with neurogenetics can substantially augment our understanding of the effects of genes and environment on social behaviours.