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International audience; Confronted with the COVID-19 crisis, healthcare professionals have had to tackle an epidemic crisis of a huge magnitude for which they were not prepared. Medical laboratories have been on the front line, from collecting samples to performing the analysis required to diagnose this new pathology. Responding to the needs and to the urgency of the situation, the authorities relied on the network of private laboratories. In France, private laboratory medicine represents 70% of overall activity, and with a network of more than 4,000 local laboratories, private laboratory medicine has been the cornerstone of the « screen-trace-isolate » strategy. This article gives feedback from private laboratory medicine professionals, directly involved in the reorganization carried out at the pre-analytical, analytical and post-analytical stages, during the crisis from March to October 2020.

Skin-derived precursor cells (SKPs) are neural crest stem cells that persist in certain adult tissues, particularly in the skin. They can generate a large type of cell in vitro, including neurons. SKPs were induced to differentiate into sensory neurons (SNs) by molecules that were previously shown to be important for the generation of SNs: purmorphamine, CHIR99021, BMP4, GDNF, BDNF, and NGF. We showed that the differentiation of SKPs induced the upregulation of neurogenins. At the end of the differentiation protocol, transcriptional analysis was performed on BRN3A and a marker of pain-sensing nerve cell PRDM12 genes: 1000 times higher for PRDM12 and 2500 times higher for BRN3A in differentiated cells than they were in undifferentiated SKPs. Using immunostaining, we showed that 65% and 80% of cells expressed peripheral neuron markers BRN3A and PERIPHERIN, respectively. Furthermore, differentiated cells expressed TRPV1, PAR2, TRPA1, substance P, CGRP, HR1. Using calcium imaging, we observed that a proportion of cells responded to histamine, SLIGKV (a specific agonist of PAR2), polygodial (a specific agonist of TRPA1), and capsaicin (a specific agonist of TRPV1). In conclusion, SKPs are able to differentiate directly into functional SNs. These differentiated cells will be very useful for further in vitro studies.

PAR2 activation in basal keratinocytes stimulates inflammation via the Ca2+-dependent production of mediators such as IL-1β, TNF-α, and TSLP. In this study, we investigated PAR2 calcium signaling and the consequent production of inflammatory mediators in differentiated human primary keratinocytes (DhPKs). Stimulation with the PAR2-activating peptide SLIGKV promoted Ca2+ store depletion in both undifferentiated human primary keratinocytes and DhPKs. SLIGKV-evoked Ca2+ store depletion did not trigger the store-operated Ca2+ entry (i.e., SOCE) through ORAI1 in DhPKs compared with undifferentiated human primary keratinocytes. The inhibition of phospholipase C and the concomitant inhibition of TRPV1 and inositol triphosphate receptor in DhPKs abrogated the SLIGKV-evoked Ca2+ store depletion; NF-κB activity; and the production of inflammatory mediators such as IL-1β, TNF-α, and TSLP. Taken together, these results indicate a key role for both InsP3R and TRPV1 in Ca2+ internal stores in the PAR2-evoked Ca2+ release and consequent skin inflammation in DhPKs. These findings may provide clues to understanding the pathological role of DhPKs in skin disorders in which PAR2 is known to be involved, such as atopic dermatitis, Netherton syndrome, and psoriasis.

National audience; Cet article présente les premiers résultats de la conception et du développement d’un capteur microonde basé sur un résonateur à stub quart d’onde. L’idée de ce travail est d’utiliser des tubes à essai standards tels que ceux utilisés au CHRU de Brest remplis d’une solution aqueuse de glucose pour en déterminer sa concentration. L’interaction entre le champ électromagnétique et la solution (eau/glucose) à mesurer peut être observée en mesurant les variations des paramètres S entre 2 et 8 GHz. La technique présentée ci-après peut être utilisée pour d’autres liquides et solutions aqueuses.

While psoriasis has been extensively studied as a prevalent dermatological disease, its impact on central nervous system is relatively unknown. We have employed MRI techniques in order to study the effect of mentally-induced itch and to reveal if any differences exist between psoriasis patients and healthy subjects. Fourteen patients with chronic psoriasis and fifteen healthy controls were asked to watch two itch inducing videos consisting of people scratching themselves in the scanner. Considering functional connectivity, our results showed that an interconnected network of brain regions was more connected in patients than in healthy controls. This network involves many regions among which the cerebellum, the antero-posterior cingulate gyrus, the thalami and the para-hippocampal and hippocampal gyri play a central role. This network mostly gathers regions involved in either itching or chronic pain sensation but not only. We show that this network can be easily divided into two subnetworks for which the variations observed are not in the same proportions when compared to healthy subjects. Our analysis of DTI images showed that chronic itch can also affect the microstructure of white matter by increasing the fractional anisotropy measure in several tracts connecting the above mentioned areas for patients.With cautious interpretations and further replication of these results, we propose that the subnetwork encoding the perception and control of itch sensation is much more affected than the rest of the network representing mentalizing and empathy. With an approach consisting of measuring microstructural changes at a local level in the brain, we also contradict the findings obtained with global measures which stated that chronic psoriasis cannot alter the anatomy of the brain. This confirms that itchy pathophysiological conditions have similar effects on functional and structural connectivity as those observed in chronic pain.

National audience; Cet article propose une caractérisation électromagnétique de solutions aqueuses contenant du glucose en concentrations variables. La nouveauté de notre travail réside dans des mesures large-bande, y compris à des fréquences relativement élevées. En outre, le comportement singulier sur une large bande de fréquence lié à la présence de glucose est ensuite observé de nouveau dans un milieu complexe : le sang humain.

International audience; This article proposes an Electromagnetic characterization of aqueous solutions containing glucose in various concentrations. Results concerning blood are also presented. Novelty of this work relies in its high frequency measurements together with its broadband character. Indeed, measurements from 100 MHz up to 50 Ghz are shown and detailed (up to 20GHz for blood). Results are discussed and a possible application is detailed.

International audience; : Due to the close interactions between the skin and peripheral nervous system, there is increasing evidence that the cutaneous innervation is an important modulator of the normal wound healing process. The communication between sensory neurons and skin cells involves a variety of molecules (neuropeptides, neurohormones, and neurotrophins) and their specific receptors expressed by both neuronal and nonneuronal skin cells. It is well established that neurotransmitters and nerve growth factors released in skin have immunoregulatory roles and can exert mitogenic actions; they could also influence the functions of the different skin cell types during the wound healing process.

In the mammalian brain, thyroid hormones regulate myelination. Their actions are mediated by interactions with nuclear receptors that function as ligand-regulated transcription factors. Two genes, α and β, encode different isoforms, of which only the β and α1 isoforms are authentic nuclear triiodothyronine (T3)-receptors (NT3R). In agreement with the important role of T3 on myelination and oligodendrocyte generation, the presence of NT3Rs has been reported in oligodendrocytes and their precursors. We and others have shown that both progenitors and oligodendrocytes in vitro express the α1 and α2 isoforms, but the expression of the β1 isoform is confined to differentiated oligodendrocytes, suggesting that they have different functions. To establish if this is the case during development in vivo, we have studied NT3R isoform expression in glial cells isolated by density gradient centrifugation from rat brains of various ages. We report the presence of the α1 NT3R and its variant α2, but not that of the β1 isoform, in newborn rat glial progenitors. The pattern of expression of β1, both at the level of mRNA and protein, parallels the increase in the number of oligodendrocytes. We found a significant change in the kinetic parameters of [125I]-T3 binding to NT3Rs in these cells during the first month of life, consisting of an increase in the binding capacity that peaks with myelination, and a significative decrease in Kd that coincides with the switch from the α to the β1 isoform. Thus, the expression of NT3R isoforms in the rat oligodendrocyte lineage changes radically from the α to the β1 isoform during the period when oligodendrocytes differentiate from progenitors., INSERM/CSIC de coopération biomédicale franco-espagnole.