Performances of rapid and connected salivary RT-LAMP diagnostic test for SARS-CoV-2 infection in ambulatory screening.

In the context of social events reopening and economic relaunch, sanitary surveillance of SARS-CoV-2 infection is still required. Here, we evaluated the diagnostic performances of a rapid, extraction-free and connected reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay on saliva. Nasopharyngeal (NP) swabs and saliva from 443 outpatients were collected simultaneously and tested by reverse-transcription quantitative PCR (RT-qPCR) as reference standard test. Seventy-one individuals (16.0%) were positive by NP and/or salivary RT-qPCR. Sensitivity and specificity of salivary RT-LAMP were 85.9% (95%CI 77.8-94.0%) and 99.5% (98.7-100%), respectively. Performances were similar for symptomatic and asymptomatic participants. Moreover, SARS-CoV-2 genetic variants were analyzed and no dominant mutation in RT-LAMP primer region was observed during the period of the study. We demonstrated that this RT-LAMP test on self-collected saliva is reliable for SARS-CoV-2 detection. This simple connected test with optional automatic results transfer to health authorities is unique and opens the way to secure professional and social events in actual context of economics restart.

Pharmacoproteomic approach to the study of drug mode of action, toxicity, and resistance: applications in diabetes and cancer.

Proteomics is a powerful technique for investigating protein expression profiles in biological systems and their modifications in response to stimuli or to particular physiological or pathophysiological conditions. It is therefore a technique of choice for the study of drug mode of action, side-effects, toxicity and resistance. It is also a valuable approach for the discovery of new drug targets. All these proteomic applications to pharmacological issues may be called pharmacoproteomics. The pharmacoproteomic approach could be particularly useful for the identification of molecular alterations implicated in type 2 diabetes and for further characterization of existing or new drugs. In oncology, proteomics is widely used for the identification of tumour-specific protein markers, and pharmacoproteomics is used for the evaluation of chemotherapy, particularly for the characterization of drug-resistance mechanisms. The large amount of data generated by pharmacoproteomic screening requires the use of bioinformatic tools to insure a pertinent interpretation. Herein, we review the applications of pharmacoproteomics to the study of type 2 diabetes and to chemoresistance in different types of cancer and the current state of this technology in these pathologies. We also suggest a number of bioinformatic solutions for proteomic data management.

Hyaluronan, a major non-protein glycosaminoglycan component of the extracellular matrix in human bone marrow, mediates dexamethasone resistance in multiple myeloma.

Originating from a post-switch memory B cell or plasma cell compartment in peripheral lymphoid tissues, malignant multiple myeloma (MM) cells accumulate in the bone marrow of patients with MM. In this favourable microenvironment, their growth and survival are dependent upon both soluble factors and physical cell-to-cell and cell-to-extracellular-matrix contacts. In this study, hyaluronan (HA), a major non-protein glycosaminoglycan component of the extracellular matrix in mammalian bone marrow, acted as a survival factor against dexamethasone (Dex)-induced apoptosis in MM cell lines. These effects were mediated through an interleukin 6 (IL-6) autocrine pathway, involving signal transducers and activators of transcription-3 phosphorylation on IL-6-dependent XG-1 and XG-6 cell lines. HA promoted accumulation of IL-6 in the culture medium without affecting IL-6 gene expression, suggesting that HA protects, stabilizes and concentrates IL-6 close to its site of secretion, thus favouring its autocrine activity. In contrast, in the IL-6-independent RPMI8226 cell line, HA survival effect was mediated through a gp80-IL-6 receptor-independent pathway, resulting in the upregulation of Bcl-2 anti-apoptotic protein expression and nuclear factor-kappaB activation. Taken together, these data suggest that HA antagonizes Dex-induced apoptosis of MM cells by favouring the autocrine activity of different cytokines or growth factors. As HA is a major component of the bone marrow extracellular matrix, these findings support the idea that HA could play a major role in the survival of MM cells in vivo, and could explain why MM cells accumulate in the bone marrow of patients with MM and escape conventional chemotherapy.

Role of insulin receptor dimerization domains in ligand binding, cooperativity, and modulation by anti-receptor antibodies.

To define the structures within the insulin receptor (IR) that are required for high affinity ligand binding, we have used IR fragments consisting of four amino-terminal domains (L1, cysteine-rich, L2, first fibronectin type III domain) fused to sequences encoded by exon 10 (including the carboxyl terminus of the alpha-subunit). The fragments contained one or both cysteine residues (amino acids 524 and 682) that form disulfides between alpha-subunits in native IR. A dimeric fragment designated IR593.CT (amino acids 1-593 and 704-719) bound (125)I-insulin with high affinity comparable to detergent-solubilized wild type IR and mIR.Fn0/Ex10 (amino acids 1-601 and 650-719) and greater than that of dimeric mIR.Fn0 (amino acids 1-601 and 704-719) and monomeric IR473.CT (amino acids 1-473 and 704-719). However, neither IR593.CT nor mIR.Fn0 exhibited negative cooperativity (a feature characteristic of the native insulin receptor and mIR.Fn0/Ex10), as shown by failure of unlabeled insulin to accelerate dissociation of bound (125)I-insulin. Anti-receptor monoclonal antibodies that recognize epitopes in the first fibronectin type III domain (amino acids 471-593) and inhibit insulin binding to wild type IR inhibited insulin binding to mIR.Fn0/Ex10 but not IR593.CT or mIR.Fn0. We conclude the following: 1) precise positioning of the carboxyl-terminal sequence can be a critical determinant of binding affinity; 2) dimerization via the first fibronectin domain alone can contribute to high affinity ligand binding; and 3) the second dimerization domain encoded by exon 10 is required for ligand cooperativity and modulation by antibodies.