Comparison of arterial wall integration of different flow diverters in rabbits: The CICAFLOW study.

BACKGROUND AND PURPOSE: New coated flow diverters (FDs) claim antithrombotic properties and increased arterial wall integration. The aim of this study is to compare in vivo endothelial coverage of coated and uncoated FD in the context of different antiplatelet regimens. METHODS: Different FDs (Silk Vista - SV, Pipeline with Shield technology - PED shield and Surpass Evolve - SE) were implanted in the aorta of rabbits, all 3 in each animal with 3 different antiplatelet regimens: no antiplatelet therapy, aspirin alone, or aspirin and ticagrelor. Four weeks after FD implantation, angiography, flat-panel CT, and optical coherence tomography (OCT) were performed before harvesting the aorta. Extensive histopathology analyses were performed including environmental scanning electron microscopy (ESEM), multiphoton microscopy (MPM) and histological staining with qualitative and/or quantitative assessment of device coverage. RESULTS: All 23 FDs that were implanted remained patent without hyperplasia. Qualitative stent coverage assessment revealed that there were no statistically significant differences between the FD groups (p = 0.19, p = 0.45, p = 0.40, and p = 0.84 for OCT, ESEM, MPM and histology, respectively). Quantitative neointimal measurement of histological sections also showed similar results in all 3 FD groups (p = 0.70). However, there were significant differences between the 3 groups of antiplatelet regimens (p = 0.07) with a higher rate in the no antiplatelet group (p = 0.05 versus aspirin alone and p = 0.03 versus aspirin and ticagrelor). CONCLUSION: Our study provides evidence that FD integration into the arterial wall is similar with coated (PED shield) and uncoated devices (SV, SE), regardless of the antiplatelet regimen. FD integration with specific surface coverage should be promoted. TRIAL REGISTRATION: APAFIS #2022011215518538.

Longitudinal follow-up of autophagy and inflammation in brain of APPswePS1dE9 transgenic mice.

BACKGROUND: In recent years, studies have sought to understand the mechanisms involved in the alteration of autophagic flux in Alzheimer's disease (AD). Alongside the recent description of the impairment of lysosomal acidification, we wanted to study the relationships between inflammation and autophagy, two physiological components deregulated in AD. Therefore, a longitudinal study was performed in APPswePS1dE9 transgenic mice at three, six and twelve months of age. METHODS: Autophagic markers (Beclin-1, p62 and LC3) and the activation of mammalian Target of Rapamycin (mTOR) signaling pathway were quantified by western blot. Cytokine levels (IL-1ß, TNF-α and IL-6) were measured by ELISA. Transmission electron microscopy was performed to detect autophagic vacuoles. Mann-Whitney tests were used to compare wild-type (WT) versus APPswePS1dE9 mice. Longitudinal changes in parameters were analyzed with a Kruskal-Wallis test followed by a post-hoc Dunn's test. Correlation between two parameters was assessed using a Spearman test. RESULTS: Compared to 12-month old WT mice, 12-month old APPswePS1dE9 mice had higher levels of IL-1ß and TNF-α, a greater inhibition of the mTOR signaling pathway and lower levels of Beclin-1 expression both in cortex and hippocampus. Regarding the relationship of the various parameters in 12-month old APPswePS1dE9 mice, Beclin-1 rates were positively correlated with IL-1ß and TNF-α levels. And, on the contrary, TNF-α levels were inversely correlated with the levels of mTOR activation. Altogether, these results suggest that inflammation could induce autophagy in APPswePS1dE9 mice. However, these transgenic mice displayed a large accumulation of autophagic vesicles within dystrophic neurons in cortex and hippocampus, indicating a terminal failure in the autophagic process. CONCLUSIONS: This first demonstration of relationships between inflammation and autophagy in in vivo models of AD should be taken into account in new therapeutic strategies to prevent inflammation and/or stimulate autophagy in advanced neurodegenerative process such as AD.

Preclinical in vitro and in vivo results of the new silk vista flow diverter with P8RI coating.

BACKGROUND: Flow diverting stents (FDS) have transformed the treatment of intracranial aneurysms; however, their metallic structure associated with their intra-luminal positioning hamper angiographic and clinical outcomes. Therefore, there is a need to develop FDS with optimized surfaces that reduce thrombogenicity while promoting the healing process and endothelialization. METHODS: P8RI, a peptide mimicking the CD31 protein, was previously developed and grafted onto Silk Vista (SV) FDS. P8RI-SV and bare-SV were used in vitro in a blood loop model to test their hemocompatibility using human whole blood and in vivo using the rabbit elastase model for optical coherence tomography (OCT) comparisons of neointimal formation at day 5 and day 28. RESULTS: After blood loop incubation, P8RI-SV showed significant reduction in fibrin binding (p=0.004) and platelet adhesion (p=0.041) compared with bare-SV. Similarly, derivative markers measured in blood, thromboxane B2 (platelet activation) and Thrombin-Antithrombin III complexes (coagulation activation), were also significantly reduced in the P8RI-SV group (both p=0.002). In vivo, complete or near-complete occlusion was reached in all aneurysms (n=6) at day 28. Excellent rate of stent-coverage ratio was obtained at day 5 (89.3% (79.1%-98.7%)) comparable to the observation at day 28 (91.8% (79.1%-100%); p=0.44). These rates were significantly higher compared with bare-SV at day 5 (77.8% (58.3%-86.8%); p<0.001) and at day 28 (67.7% (52.6%-88.9%); p<0.0001). CONCLUSION: In vitro results confirm enhanced hemocompatibility with a significant anti-thrombotic effect of the P8RI-SV. In vivo results provide evidence of rapid neo-intimal growth reaching near-complete tissue healing as early as day 5 in a rabbit model.

WEB shape modifications: angiography-histopathology correlations in rabbits.

BACKGROUND: WEB Shape Modification (WSM) over time is frequent after aneurysm treatment. In this study, we explored the relationship between histopathological changes and angiographic evolution over time in experimental aneurysms in rabbits treated with the Woven EndoBridge (WEB) procedure. METHODS: Quantitative WSM was assessed using flat-panel computed tomography (FPCT) during follow-up by calculating height and width ratio (HR, WR), defined as the ratio between either measurement at an index time point and the measurement immediately after WEB implantation. The index time point varied from 1 day to 6 months. HR and WR were evaluated with angiographic and histopathological assessments of aneurysm healing. RESULTS: Final HR of devices varied from 0.30 to 1.02 and final WR varied from 0.62 to 1.59. Altogether, at least 5% of HR and WR variations were observed in 37/40 (92.5%) and 28/40 (70%) WEB devices, respectively, at the time of final assessment. There was no significant correlation between complete or incomplete occlusion groups and HR or WR (p=0.15 and p=0.43). Histopathological analysis revealed a significant association between WR and aneurysm healing and fibrosis 1 month following aneurysm treatment (both p<0.05). CONCLUSION: Using longitudinal FPCT assessment, we observed that WSM affects both the height and width of the WEB device. No significant association was found between WSM and aneurysm occlusion status. Although presumably a multifactorial phenomenon, the histopathological analysis highlighted a significant association between width variations, aneurysm healing and fibrosis in the first month following aneurysm treatment.

Involvement of interleukin-1ß in the autophagic process of microglia: relevance to Alzheimer's disease.

BACKGROUND: Autophagy is a major pathway of protein and organelle degradation in the lysosome. Autophagy exists at basal constitutive level and can be induced as a defense mechanism under stress conditions. Molecular relationships between autophagy and inflammation at the periphery were recently evidenced, highlighting a role of autophagy in the regulation of inflammation. Impairment of autophagy (with accumulation of autophagic vacuoles) and substantial inflammation are found in neurodegenerative diseases such as Alzheimer's Disease (AD). However, the links between autophagy and inflammation in AD remain to be determined. METHODS: Here, we examined the inflammatory reaction and autophagy in murine tri-cultures of neurons, astrocytes, and microglia. Tri-cultures were exposed to various inflammatory stresses (lipopolysaccharide (LPS), amyloid peptide (Aß42) with or without cytokines) for 48 hours. Furthermore, the relationships between inflammation and autophagy were also analyzed in astrocyte- and microglia-enriched cultures. Data for multiple variable comparisons were analyzed by a one-way ANOVA followed by a Newman-keuls' test. RESULTS: Aß42 induced a low inflammation without accumulation of acidic vesicles contrary to moderate or severe inflammation induced by LPS or the cytokine cocktail (IL-1ß, TNF-α, and IL-6) or IL-1ß alone which led to co-localization of p62 and LC3, two markers of autophagy, with acidic vesicles stained with Lyso-ID Red dye. Moreover, the study reveals a major role of IL-1ß in the induction of autophagy in tri-cultures in the presence or absence of Aß42. However, the vulnerability of the autophagic process in purified microglia to IL-1ß was prevented by Aß42. CONCLUSION: These findings show a close relationship between inflammation and autophagy, in particular a major role of IL-1ß in the induction of the microglial autophagy which could be the case in AD. New therapeutic strategies could target inflammasome and autophagy in microglia to maintain its role in the amyloid immunosurveillance.

Study of p53 expression and post-transcriptional modifications after GSM-900 radiofrequency exposure of human amniotic cells.

The potential effects of radiofrequency (RF) exposure on the genetic material of cells are very important to determine since genome instability of somatic cells may be linked to cancer development. In response to genetic damage, the p53 protein is activated and can induce cell cycle arrest allowing more time for DNA repair or elimination of damaged cells through apoptosis. The objective of this study was to investigate whether the exposure to RF electromagnetic fields, similar to those emitted by mobile phones of the second generation standard, Global System for Mobile Communications (GSM), may induce expression of the p53 protein and its activation by post-translational modifications in cultured human cells. The potential induction of p53 expression and activation by GSM-900 was investigated after in vitro exposure of human amniotic cells for 24 h to average specific absorption rates (SARs) of 0.25, 1, 2, and 4 W/kg in the temperature range of 36.3-39.7 °C. The exposures were carried out using a wire-patch cell (WPC) under strictly controlled conditions of temperature. Expression and activation of p53 by phosphorylation at serine 15 and 37 were studied using Western blot assay immediately after three independent exposures of cell cultures provided from three different donors. Bleomycin-exposed cells were used as a positive control. According to our results, no significant changes in the expression and activation of the p53 protein by phosphorylation at serine 15 and 37 were found following exposure to GSM-900 for 24 h at average SARs up to 4 W/kg in human embryonic cells.

Use of high-plex data provides novel insights into the temporal artery processes of giant cell arteritis.

Objective: To identify the key coding genes underlying the biomarkers and pathways associated with giant cell arteritis (GCA), we performed an in situ spatial profiling of molecules involved in the temporal arteries of GCA patients and controls. Furthermore, we performed pharmacogenomic network analysis to identify potential treatment targets. Methods: Using human formalin-fixed paraffin-embedded temporal artery biopsy samples (GCA, n = 9; controls, n = 7), we performed a whole transcriptome analysis using the NanoString GeoMx Digital Spatial Profiler. In total, 59 regions of interest were selected in the intima, media, adventitia, and perivascular adipose tissue (PVAT). Differentially expressed genes (DEGs) (fold-change > 2 or < -2, p-adjusted < 0.01) were compared across each layer to build a spatial and pharmacogenomic network and to explore the pathophysiological mechanisms of GCA. Results: Most of the transcriptome (12,076 genes) was upregulated in GCA arteries, compared to control arteries. Among the screened genes, 282, 227, 40, and 5 DEGs were identified in the intima, media, adventitia, and PVAT, respectively. Genes involved in the immune process and vascular remodeling were upregulated within GCA temporal arteries but differed across the arterial layers. The immune-related functions and vascular remodeling were limited to the intima and media. Conclusion: This study is the first to perform an in situ spatial profiling characterization of the molecules involved in GCA. The pharmacogenomic network analysis identified potential target genes for approved and novel immunotherapies.

DC2 and keratinocyte-associated protein 2 (KCP2), subunits of the oligosaccharyltransferase complex, are regulators of the gamma-secretase-directed processing of amyloid precursor protein (APP).

The oligosaccharyltransferase complex catalyzes the transfer of oligosaccharide from a dolichol pyrophosphate donor en bloc onto a free asparagine residue of a newly synthesized nascent chain during the translocation in the endoplasmic reticulum lumen. The role of the less known oligosaccharyltransferase (OST) subunits, DC2 and KCP2, recently identified still remains to be determined. Here, we have studied DC2 and KCP2, and we have established that DC2 and KCP2 are substrate-specific, affecting amyloid precursor protein (APP), indicating that they are not core components required for N-glycosylation and OST activity per se. We show for the first time that DC2 and KCP2 depletion affects APP processing, leading to an accumulation of C-terminal fragments, both C99 and C83, and a reduction in full-length mature APP. This reduction in mature APP levels was not due to a block in secretion because the levels of sAPPα secreted into the media were unaffected. We discover that DC2 and KCP2 depletion affects only the γ-secretase complex, resulting in a reduction of the PS1 active fragment blocking Aß production. Conversely, we show that the overexpression of DC2 and KCP2 causes an increase in the active γ-secretase complex, particularly the N-terminal fragment of PS1 that is generated by endoproteolysis, leading to a stimulation of Aß production upon overexpression of DC2 and KCP2. Our findings reveal that components of the OST complex for the first time can interact with the γ-secretase and affect the APP processing pathway.

The new indirubin derivative inhibitors of glycogen synthase kinase-3, 6-BIDECO and 6-BIMYEO, prevent tau phosphorylation and apoptosis induced by the inhibition of protein phosphatase-2A by okadaic acid in cultured neurons.

Alterations in glycogen synthase kinase-3ß (GSK3ß) and protein phosphatase-2A (PP2A) have been proposed to be involved in the abnormal tau phosphorylation and aggregation linked to Alzheimer's disease (AD). Interconnections between GSK3ß and PP2A signaling pathways are well established. Targeting tau kinases was proposed to represent a therapeutic strategy for AD. However, which tau kinases should be blocked and to what extent, keeping in mind that kinases have physiological roles? Because most kinase inhibitors are relatively specific and many of them interfere with the cell cycle, it is necessary to develop more specific tau kinase inhibitors devoid of cell toxicity. Here, we used the PP2A inhibition by okadaic acid (OKA) in primary cultured cortical neurons as an in vitro model of increased tau phosphorylation and apoptosis. We tested the effects of two newly characterized indirubin derivative inhibitors of GSK3, 6-BIDECO (6-bromoindirubin-3'-[O-(N,N-diethylcarbamyl)-oxime] and 6-BIMYEO (6-bromoindirubin-3'-[O-(2-morpholin-1-ylethyl)-oxime] hydrochloride) on OKA-induced tau phosphorylation and neuronal apoptosis. Both compounds exhibit higher selectivity toward GSK3 compared with other tau kinases (for 6-BIDECO, IC50 is 0.03 µM for GSK3, >10 µM for CDK1, and 10 µM for CDK5; for 6-BIMYEO, IC50 is 0.11 µM for GSK3, 1.8 µM for CDK1, and 0.9 µM for CDK5). We show that 6-BIDECO and 6-BIMYEO used at micromolar concentrations are not neurotoxic and potently reversed tau phosphorylation and apoptosis induced by OKA. The neuroprotection by these compounds should be further validated in animal models of AD.

Uterus tolerance to extended cold ischemic storage after auto-transplantation in ewes.

OBJECTIVE: To assess how the uterus tolerates extended cold ischemic storage before auto-transplantation in ewes. STUDY DESIGN: Fourteen uterine auto-transplantations were performed in ewes from November 2014 to June 2015 at the Analysis and Research Laboratory of Limoges, France. The animals were divided into 2 groups: 7 after 3h of cold ischemia timeand 7 after 24h. Transplant was assessed ≥8days after transplantation. Histology and apoptosis analyses (TUNEL method and indirect immunohistochemistry of cleaved Caspase 3) were performed before uterus retrieval (control), after 90min following reperfusion and ≥8days after transplantation. RESULTS: Twelve uterine auto-transplantations were successfully performed. The histological analysis at 90min following reperfusion revealed a moderate inflammation of the endometrium and serosa in the 3-h group and severe inflammation in the 24-h group, but no significant apoptotic signal was found in either group. Seven ewes were alive at ≥8days after transplantation: the macroscopic and histological analyses revealed two viable uteri in the 3-h group and three in the 24-h group. In each group one uterus was necrotic. CONCLUSION: These first results in ewes suggest that the uterus is an organ with a good tolerance to extended cold ischemic storage before transplantation.

The Role of Endoproteolytic Processing in Neurodegeneration.

Endoproteolysis is a normal post-translational process in the eukaryotic cell that plays a role in protein evolution allowing protein catabolism and the generation of amino acids. Endoproteolytic cleavage regulates many crucial cellular processes including the activity of many proteins, their protein-protein interactions and the amplification of cell signals. Not surprisingly, disruption or alternation of endoproteolytic cleavage may be the root cause of many human diseases such as Alzheimer's disease, Huntington's disease and prion diseases. Most neurodegenerative diseases (ND) are caused by the build-up of misfolded proteins and the promotion of aggregation events. A common event that occurs in these ND is the alteration of endoproteolytic cleavage due to genetic mutations of the associated-proteases or target substrate. Endoproteolytic cleavage resulting in protein truncation has significant effects on the structure and function of a protein representing a common feature of ND. In this review, we will discuss the endoproteolytic cleavage events that lead to ND, namely Alzheimer's disease, Huntington's disease and prion diseases.

Maladaptative Autophagy Impairs Adipose Function in Congenital Generalized Lipodystrophy due to Cavin-1 Deficiency.

CONTEXT: Mutations in PTRF encoding cavin-1 are responsible for congenital generalized lipodystrophy type 4 (CGL4) characterized by lipoatrophy, insulin resistance, dyslipidemia, and muscular dystrophy. Cavin-1 cooperates with caveolins to form the plasma membrane caveolae, which are involved in cellular trafficking and signalling and in lipid turnover. OBJECTIVE: We sought to identify PTRF mutations in patients with CGL and to determine their impact on insulin sensitivity, adipose differentiation, and cellular autophagy. DESIGN AND PATIENTS: We performed phenotyping studies and molecular screening of PTRF in two unrelated families with CGL. Cellular studies were conducted in cultured skin fibroblasts from the two probands and from control subjects, and in murine 3T3-F442A preadipocytes. Knockdown of cavin-1 or ATG5 was obtained by small interfering RNA-mediated silencing. RESULTS: We identified two new PTRF homozygous mutations (p.Asp59Val or p.Gln157Hisfs*52) in four patients with CGL4 presenting with generalized lipoatrophy and associated metabolic abnormalities. In probands' fibroblasts, cavin-1 expression was undetectable and caveolin-1 and -2 barely expressed. Ultrastructural analysis revealed a loss of membrane caveolae and the presence of numerous cytoplasmic autophagosomes. Patients' cells also showed increased autophagic flux and blunted insulin signaling. These results were reproduced by PTRF knockdown in control fibroblasts and in 3T3-F442A preadipocytes. Cavin-1 deficiency also impaired 3T3-F442A adipocyte differentiation. Suppression of autophagy by small interfering RNA-mediated silencing of ATG5 improved insulin sensitivity and adipocyte differentiation. CONCLUSIONS: This study showed that cavin-1 deficiency resulted in maladaptative autophagy that contributed to insulin resistance and altered adipocyte differentiation. These new pathophysiological mechanisms could open new therapeutic perspectives for adipose tissue diseases including CGL4.

Inflammatory Stress on Autophagy in Peripheral Blood Mononuclear Cells from Patients with Alzheimer's Disease during 24 Months of Follow-Up.

Recent findings indicate that microglia in Alzheimer's disease (AD) is senescent whereas peripheral blood mononuclear cells (PBMCs) could infiltrate the brain to phagocyte amyloid deposits. However, the molecular mechanisms involved in the amyloid peptide clearance remain unknown. Autophagy is a physiological degradation of proteins and organelles and can be controlled by pro-inflammatory cytokines. The purpose of this study was to evaluate the impact of inflammation on autophagy in PBMCs from AD patients at baseline, 12 and 24 months of follow-up. Furthermore, PBMCs from healthy patients were also included and treated with 20 µM amyloid peptide 1-42 to mimic AD environment. For each patient, PBMCs were stimulated with the mitogenic factor, phytohaemagglutin (PHA), and treated with either 1 µM C16 as an anti-inflammatory drug or its vehicle. Autophagic markers (Beclin-1, p62/sequestosome 1 and microtubule-associated protein-light chain 3: LC3) were quantified by western blot and cytokines (Interleukin (IL)-1ß, Tumor necrosis Factor (TNF)-α and IL-6) by Luminex X-MAP® technology. Beclin-1 and TNF-α levels were inversely correlated in AD PBMCs at 12 months post-inclusion. In addition, Beclin-1 and p62 increased in the low inflammatory environment induced by C16. Only LC3-I levels were inversely correlated with cognitive decline at baseline. For the first time, this study describes longitudinal changes in autophagic markers in PBMCs of AD patients under an inflammatory environment. Inflammation would induce autophagy in the PBMCs of AD patients while an anti-inflammatory environment could inhibit their autophagic response. However, this positive response could be altered in a highly aggressive environment.

Induction of antiproliferative effect by diosgenin through activation of p53, release of apoptosis-inducing factor (AIF) and modulation of caspase-3 activity in different human cancer cells.

Previously, we demonstrated that a plant steroid, diosgenin, altered cell cycle distribution and induced apoptosis in the human osteosarcoma 1547 cell line. The objective of this study was to investigate if the antiproliferative effect of diosgenin was similar for different human cancer cell lines such as laryngocarcinoma HEp-2 and melanoma M4Beu cells. Moreover, this work essentially focused on the mitochondrial pathway. We found that diosgenin had an important and similar antiproliferative effect on different types of cancer cells. In addition, our new results show that diosgenin-induced apoptosis is caspase-3 dependent with a fall of mitochondrial membrane potential, nuclear localization of AIF and poly (ADP-ribose) polymerase cleavage. Diosgenin treatment also induces p53 activation and cell cycle arrest in the different cell lines studied.

BAD and Bcl-2 regulation are early events linking neuronal endoplasmic reticulum stress to mitochondria-mediated apoptosis.

The mechanism of endoplasmic reticulum (ER)-mediated apoptosis in neurons was examined. Using primary cortical neurons, we show that nordihydroguaiaretic acid (NDGA) and brefeldin A (BFA), two ER stressors, induce early ER stress as shown by Western blotting of the eukaryotic initiation factor-2alpha (eIF2alpha), an ER stress marker. This event was associated with an enhancement of neuronal apoptosis as demonstrated by the time-dependent increase in caspase-3 activity and by nuclear fragmentation. The study of the apoptotic signaling showed the translocation of cytochrome c from the mitochondrial matrix to the cytosol. Further evaluation of the apoptotic process revealed that NDGA and BFA induced a rapid dephosphorylation of BAD and decrease expression of Bcl-2. Altogether, our results indicate that neuronal ER stress is associated with an apoptotic cascade involving the mitochondria.

Autophagy dysfunction and its link to Alzheimer's disease and type II diabetes mellitus.

Epidemiological data testifies the increasing incidence of Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). Some associations were made between occidental lifestyle and development of these pathologies, moreover AD and T2DM are linked since each pathology is a causative risk factor for the other. Interestingly, autophagy, a catabolic pathway whose efficiency declines with age is importantly impaired in the affected tissues. Autophagy regulation is dependent of cell metabolic status and consequently on the 5'AMP-activated protein kinase (AMPK) and mammalian target of rapamycin signaling pathways. These pathways are altered with aging and molecular, pharmacological and physiological interventions increase lifespan in various organismal models and favours healthy aging diminishing the occurrence of age-related diseases such as diabetes, cancer, cardiovascular and neurodegenerative pathologies. Decreasing calorie intake has been known for a long time to have a beneficial effect on longevity and health. Some drug agonists of AMPK are known to mimic these effects such as metformin or resveratrol, a polyphenol extracted from plants and present in red wine, a component of the French paradox related diet. In this review, we present the epidemiological and pathogenesis links existing between AD and T2DM with an insight into the perturbations of the autophagic process highlighting the crucial role of the AMPK in development of age and metabolic related diseases. Hence, in a last part we will discuss the possible interventions susceptible to combat both T2DM and AD.

Impairment of autophagy in the central nervous system during lipopolysaccharide-induced inflammatory stress in mice.

BACKGROUND: Current evidence suggests a central role for autophagy in many neurodegenerative diseases including Alzheimer's disease, Huntington's disease, Parkinson's disease and amyotrophic lateral sclerosis. Furthermore, it is well admitted that inflammation contributes to the progression of these diseases. Interestingly, crosstalks between autophagy and inflammation have been reported in vitro and at the peripheral level such as in Crohn's disease. However, the impact of systemic inflammation on autophagic components in the brain remains to be documented. Therefore, this study monitored autophagy markers after acute and chronic lipopolysaccharide (LPS)-induced inflammatory stress in mice. RESULTS: We showed that acute inflammation, 24 h post-intraperitoneal 10 mg/kg LPS, substantially increased cytokine production (Interleukin(IL)-1ß, Tumor necrosis factor (TNF)-α and IL-6), decreased the levels of autophagy markers (Beclin-1, p62 and LC3 II) and reduced p70S6K activation in cortex and hippocampus. In hippocampus, IL-1ß levels and LC3 II expression were positively and highly correlated and a negative correlation was noted between TNF-α levels and p70S6K activation. Chronic inflammation by injection of 0.5 mg/kg LPS every three days during three months led to a moderate IL-1ß production and decreased TNF-α levels. Interestingly, Beclin-1 and LC3 II levels decreased while those of p62 increased. Cortical IL-1ß levels positively correlated with Beclin-1 and LC3 II and on the contrary inversely correlated with p62. CONCLUSION: The present study is the first showing links between IL-1ß-mediated inflammation and autophagy in the brain. It could open to new therapeutic strategies in brain diseases where regulation impairment of inflammation and autophagy progress with the severity of diseases.

Tau protein phosphatases in Alzheimer's disease: the leading role of PP2A.

Tau phosphorylation is regulated by a balance between tau kinase and phosphatase activities. Disruption of this equilibrium was suggested to be at the origin of abnormal tau phosphorylation and thereby that might contributes to tau aggregation. Thus, understanding the regulation modes of tau dephosphorylation is of high interest in determining the possible causes at the origin of the formation of tau aggregates and to elaborate protection strategies to cope with these lesions in AD. Among the possible and relatively specific interventions that reverse tau phosphorylation is the stimulation of certain tau phosphatases. Here, we reviewed tau protein phosphatases, their physiological roles and regulation, their involvement in tau phosphorylation and the relevance to AD. We also reviewed the most common compounds acting on each tau phosphatase including PP2A.

PP2A blockade inhibits autophagy and causes intraneuronal accumulation of ubiquitinated proteins.

Using cultured cortical neurons, we show that the blockade of protein phosphatase 2A (PP2A), either pharmacologically by okadaic acid or by short hairpin RNA (shRNA)-mediated silencing of PP2A catalytic subunit, inhibited basal autophagy and autophagy induced in several experimental settings (including serum deprivation, endoplasmic reticulum stress, rapamycin, and proteasome inhibition) at early stages before autophagosome maturation. Conversely, PP2A upregulation by PP2A catalytic subunit overexpression stimulates neuronal autophagy. In addition, PP2A blockade resulted in the activation of the negative regulator of autophagy mammalian target of rapamycin complex 1 and 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK) and led to intraneuronal accumulation of p62- and ubiquitin-positive protein inclusions, likely due to autophagy downregulation. These data are consistent with previous findings showing that specific invalidation of the autophagy process in the nervous system of mouse resulted in the accumulation of p62- and ubiquitin-positive protein inclusion bodies. Furthermore, we showed that PP2A inhibition alters the distribution of the microtubule-associated protein 1 light chain(LC) 3-I (MAP LC3-I), a key component of the autophagy molecular machinery. Whether MAP LC3-I distribution in the cell accounts for autophagy regulation remains to be determined. These data are important to human neurodegenerative diseases, especially Alzheimer's disease, because they provide links for the first time between the pathological features of Alzheimer's disease:PP2A downregulation, autophagy disruption, and protein aggregation.

Tau protein kinases: involvement in Alzheimer's disease.

Tau phosphorylation is regulated by a balance between tau kinase and phosphatase activities. Disruption of this equilibrium was suggested to be at the origin of abnormal tau phosphorylation and thereby might contribute to tau aggregation. Thus, understanding the regulation modes of tau phosphorylation is of high interest in determining the possible causes at the origin of the formation of tau aggregates in order to elaborate protection strategies to cope with these lesions in Alzheimer's disease. Among the possible and specific interventions that reverse tau phosphorylation is the inhibition of certain tau kinases. Here, we extensively reviewed tau protein kinases, their physiological roles and regulation, their involvement in tau phosphorylation and their relevance to AD. We also reviewed the most common inhibitory compounds acting on each tau kinase.