Vitamin D interacts with Esr1 and Igf1 to regulate molecular pathways relevant to Alzheimer’s disease

International audienceAbstractBackgroundIncreasing evidence suggests a potential therapeutic benefit of vitamin D supplementation against Alzheimer’s disease (AD). Although studies have shown improvements in cognitive performance and decreases in markers of the pathology after chronic treatment, the mechanisms by which vitamin D acts on brain cells are multiple and remain to be thoroughly studied. We analyzed the molecular changes observed after 5 months of vitamin D3 supplementation in the brains of transgenic 5xFAD (Tg) mice, a recognized mouse model of AD, and their wild type (Wt) littermates. We first performed a kinematic behavioural examination at 4, 6 and 8 months of age (M4, M6 and M8) followed by a histologic assessment of AD markers. We then performed a comparative transcriptomic analysis of mRNA regulation in the neocortex and hippocampus of 9 months old (M9) female mice.ResultsTranscriptomic analysis of the hippocampus and neocortex of both Wt and Tg mice at M9, following 5 months of vitamin D3 treatment, reveals a large panel of dysregulated pathways related to i) immune and inflammatory response, ii) neurotransmitter activity, iii) endothelial and vascular processes and iv) hormonal alterations. The differentially expressed genes are not all direct targets of the vitamin D-VDR pathway and it appears that vitamin D action engages in the crosstalk with estrogen and insulin signaling. The misexpression of the large number of genes observed in this study translates into improved learning and memory performance and a decrease in amyloid plaques and astrogliosis in Tg animals.ConclusionsThis study underlies the multiplicity of action of this potent neurosteroid in an aging and AD-like brain. The classical and non-classical actions of vitamin D3 can act in an additive and possibly synergistic manner to induce neuroprotective activities in a context-specific way

Secretory Leukocyte Protease Inhibitor (SLPI) Is, like Its Homologue Trappin-2 (Pre-Elafin), a Transglutaminase Substrate

Human lungs contain secretory leukocyte protease inhibitor (SLPI), elafin and its biologically active precursor trappin-2 (pre-elafin). These important low-molecular weight inhibitors are involved in controlling the potentially deleterious proteolytic activities of neutrophil serine proteases including elastase, proteinase 3 and cathepsin G. We have shown previously that trappin-2, and to a lesser extent, elafin can be linked covalently to various extracellular matrix proteins by tissue transglutaminases and remain potent protease inhibitors. SLPI is composed of two distinct domains, each of which is about 40% identical to elafin, but it lacks consensus transglutaminase sequence(s), unlike trappin-2 and elafin. We investigated the actions of type 2 tissue transglutaminase and plasma transglutaminase activated factor XIII on SLPI. It was readily covalently bound to fibronectin or elastin by both transglutaminases but did not compete with trappin-2 cross-linking. Cross-linked SLPI still inhibited its target proteases, elastase and cathepsin G. We have also identified the transglutamination sites within SLPI, elafin and trappin-2 by mass spectrometry analysis of tryptic digests of inhibitors cross-linked to mono-dansyl cadaverin or to a fibronectin-derived glutamine-rich peptide. Most of the reactive lysine and glutamine residues in SLPI are located in its first N-terminal elafin-like domain, while in trappin-2, they are located in both the N-terminal cementoin domain and the elafin moiety. We have also demonstrated that the transglutamination substrate status of the cementoin domain of trappin-2 can be transferred from one protein to another, suggesting that it may provide transglutaminase-dependent attachment properties for engineered proteins. We have thus added to the corpus of knowledge on the biology of these potential therapeutic inhibitors of airway proteases

Temporal gene profiling of the 5XFAD transgenic mouse model highlights the importance of microglial activation in Alzheimer’s disease

International audienceBackground: The 5XFAD early onset mouse model of Alzheimer's disease (AD) is gaining momentum. Behavioral, electrophysiological and anatomical studies have identified age-dependent alterations that can be reminiscent of human AD. However, transcriptional changes during disease progression have not yet been investigated. To this end, we carried out a transcriptomic analysis on RNAs from the neocortex and the hippocampus of 5XFAD female mice at the ages of one, four, six and nine months (M1, M4, M6, M9). Results: Our results show a clear shift in gene expression patterns between M1 and M4. At M1, 5XFAD animals exhibit region-specific variations in gene expression patterns whereas M4 to M9 mice share a larger proportion of differentially expressed genes (DEGs) that are common to both regions. Analysis of DEGs from M4 to M9 underlines the predominance of inflammatory and immune processes in this AD mouse model. The rise in inflammation, sustained by the overexpression of genes from the complement and integrin families, is accompanied by an increased expression of transcripts involved in the NADPH oxidase complex, phagocytic processes and IFN-γ related pathways. Conclusions: Overall, our data suggest that, from M4 to M9, sustained microglial activation becomes the predominant feature and point out that both detrimental and neuroprotective mechanisms appear to be at play in this model. Furthermore, our study identifies a number of genes already known to be altered in human AD, thus confirming the use of the 5XFAD strain as a valid model for understanding AD pathogenesis and for screening potential therapeutic molecules

Development of an anti-inflammatory therapeutic strategy for the treatment of long diseases based on the administration of anti-proteases

Les travaux de cette thèse ont porté sur l’étude des propriétés fonctionnelles d’inhibiteurs recombinants polyvalents ciblant les trois protéases à sérine du neutrophile (élastase, protéase 3, cathepsine G), libérées massivement au cours des inflammations pulmonaires. Ces inhibiteurs, dérivés de molécules naturelles (élafine, trappine-2, SLPI), interagissent fortement avec les trois protéases à sérine, sous forme soluble ou liée aux membranes des neutrophiles et possèdent des propriétés anti-bactériennes indépendantes de leurs capacités inhibitrices. De plus, nous avons montré que ces inhibiteurs peuvent être ancrés à différentes protéines de structure par transglutamination tout en conservant leurs propriétés inhibitrices. Par leurs différentes propriétés, ces inhibiteurs représentent des molécules particulièrement attractives dans le cadre du développement d’une stratégie thérapeutique basée sur l’administration d’anti-protéases par aérosol pour le traitement de maladies pulmonaires inflammatoires.In this study, we have analysed the properties of recombinant polyvalent inhibitors of the three neutrophil serine proteinases (elastase, proteinase 3, cathepsin G), massively released during inflammatory events in various lung diseases. These inhibitors, derived from natural endogeneous inhibitors (elafin, trappin-2, SLPI), interact tightly with both free and membrane-bound neutrophil serine proteinases and possess antimicrobial properties that are independent from their inhibitory capacity. We have also shown that these polyvalent inhibitors can be covalently bound to the extracellular matrix proteins by a transglutaminase and that they retain their inhibitory properties in these conditions. With their various biological properties, these inhibitors are attractive molecules for the development of an aerosol-based therapeutic strategy for the treatment of inflammatory lung diseases

MT5-MMP, just a new APP processing proteinase in Alzheimer's disease?

International audienceWe have recently identified in a transgenic mouse model of Alzheimer's ă disease (AD) membrane-type 5-MMP (MT5-MMP) as a new player in ă Alzheimer's pathogenesis, which displays pro-amyloidogenic features and ă proteolytic processing of amyloid precursor protein (APP). Another group ă has reported that MT5-MMP processing of APP may release a novel ă neurotoxic APP fragment. Although MT5-MMP-mediated APP processing ă appears to be a key pathogenic step, we hypothesize that MT5-MMP may ă also contribute to AD pathogenesis through complementary mechanisms that ă involve the activation of pro-inflammatory pathways and/or APP ă trafficking

Développement d'une stratégie thérapeutique anti-inflammatoire en pathologie pulmonaire basée sur l'administration d'anti-protéases

Les travaux de cette thèse ont porté sur l étude des propriétés fonctionnelles d inhibiteurs recombinants polyvalents ciblant les trois protéases à sérine du neutrophile (élastase, protéase 3, cathepsine G), libérées massivement au cours des inflammations pulmonaires. Ces inhibiteurs, dérivés de molécules naturelles (élafine, trappine-2, SLPI), interagissent fortement avec les trois protéases à sérine, sous forme soluble ou liée aux membranes des neutrophiles et possèdent des propriétés anti-bactériennes indépendantes de leurs capacités inhibitrices. De plus, nous avons montré que ces inhibiteurs peuvent être ancrés à différentes protéines de structure par transglutamination tout en conservant leurs propriétés inhibitrices. Par leurs différentes propriétés, ces inhibiteurs représentent des molécules particulièrement attractives dans le cadre du développement d une stratégie thérapeutique basée sur l administration d anti-protéases par aérosol pour le traitement de maladies pulmonaires inflammatoires.In this study, we have analysed the properties of recombinant polyvalent inhibitors of the three neutrophil serine proteinases (elastase, proteinase 3, cathepsin G), massively released during inflammatory events in various lung diseases. These inhibitors, derived from natural endogeneous inhibitors (elafin, trappin-2, SLPI), interact tightly with both free and membrane-bound neutrophil serine proteinases and possess antimicrobial properties that are independent from their inhibitory capacity. We have also shown that these polyvalent inhibitors can be covalently bound to the extracellular matrix proteins by a transglutaminase and that they retain their inhibitory properties in these conditions. With their various biological properties, these inhibitors are attractive molecules for the development of an aerosol-based therapeutic strategy for the treatment of inflammatory lung diseases.TOURS-Bibl.électronique (372610011) / SudocSudocFranceF

Emerging Alternative Proteinases in APP Metabolism and Alzheimer’s Disease Pathogenesis: A Focus on MT1-MMP and MT5-MMP

International audienceProcessing of amyloid beta precursor protein (APP) into amyloid-beta peptide (Aβ) by β-secretase and γ-secretase complex is at the heart of the pathogenesis of Alzheimer's disease (AD). Targeting this proteolytic pathway effectively reduces/prevents pathology and cognitive decline in preclinical experimental models of the disease, but therapeutic strategies based on secretase activity modifying drugs have so far failed in clinical trials. Although this may raise some doubts on the relevance of β-and γ-secretases as targets, new APP-cleaving enzymes, including meprin-β, legumain (δ-secretase), rhomboid-like protein-4 (RHBDL4), caspases and membrane-type matrix metalloproteinases (MT-MMPs/η-secretases) have confirmed that APP processing remains a solid mechanism in AD pathophysiology. This review will discuss recent findings on the roles of all these proteinases in the nervous system, and in particular on the roles of MT-MMPs, which are at the crossroads of pathological events involving not only amyloidogenesis, but also inflammation and synaptic dysfunctions. Assessing the potential of these emerging proteinases in the Alzheimer's field opens up new research prospects to improve our knowledge of fundamental mechanisms of the disease and help us establish new therapeutic strategies

Matrix metalloproteinases as new targets in Alzheimer's disease: Opportunities and Challenges

International audienceAlthough matrix metalloproteinases (MMPs) are implicated in the regulation of numerous physiological processes, evidences of their pathological roles have also been obtained in the last decades, making MMPs attractive therapeutic targets for several diseases. Recent discoveries of their involvement in central nervous system (CNS) disorders, and in particular in Alzheimer's disease (AD), have paved the way to consider MMP modulators as promising therapeutic strategies. Over the past few decades, diverse approaches have been undertaken in the design o

Matrix metalloproteinases as new targets in Alzheimer's disease: Opportunities and Challenges

International audienceAlthough matrix metalloproteinases (MMPs) are implicated in the regulation of numerous physiological processes, evidences of their pathological roles have also been obtained in the last decades, making MMPs attractive therapeutic targets for several diseases. Recent discoveries of their involvement in central nervous system (CNS) disorders, and in particular in Alzheimer's disease (AD), have paved the way to consider MMP modulators as promising therapeutic strategies. Over the past few decades, diverse approaches have been undertaken in the design o

Matrix metalloproteinases as new targets in Alzheimer's disease: Opportunities and Challenges

International audienceAlthough matrix metalloproteinases (MMPs) are implicated in the regulation of numerous physiological processes, evidences of their pathological roles have also been obtained in the last decades, making MMPs attractive therapeutic targets for several diseases. Recent discoveries of their involvement in central nervous system (CNS) disorders, and in particular in Alzheimer's disease (AD), have paved the way to consider MMP modulators as promising therapeutic strategies. Over the past few decades, diverse approaches have been undertaken in the design o