Secretase-Independent and RhoGTPase/PAK/ERK-Dependent Regulation of Cytoskeleton Dynamics in Astrocytes by NSAIDs and Derivatives

Institut de Neurociènces, Universitat Autònoma de Barcelona, Spain.
Journal of Alzheimer's disease: JAD (Impact Factor: 4.15). 10/2010; 22(4):1135-55. DOI: 10.3233/JAD-2010-101332
Source: PubMed


Profens like ibuprofen, R-flurbiprofen, or CHF5074 are being considered for the treatment of Alzheimer's disease because epidemiological data indicates that non-steroidal anti-inflammatory drugs are protective against neurodegeneration. Rho-GTPases are small G proteins, including RhoA, Cdc42, and Rac1, which control cytoskeleton dynamics. Because ibuprofen promotes axon growth via RhoA in neurons, we examined whether profens modulate astrocyte plasticity via Rho-GTPases. We report that ibuprofen (100-500 μM), R-flurbiprofen (100-500 μM), and CHF5074 (10-30 μM) caused a concentration-dependent stellation of astrocytes in primary cultures, associated with the reorganization of GFAP and actin filaments. The stellation was independent of COX2, α-, β- or γ-secretase as judged by the lack of effect of inhibitors of these enzymes. RhoA, PAK, and Cdc42, but not Rac1, accounted for the profen-mediated stellation, as concluded from the joint analyses of activities and reversal experiments with adenoviral or pharmacological manipulations. Ibuprofen accelerated migration in a scratch-wound assay, while R-flurbiprofen had no effect and CHF5074 caused deceleration. Cell polarity regulation by Cdc42 and ERK1/2 may underlie the paradoxical effects of profens on migration. We conclude that profens regulate cytoskeleton dynamics in astrocytes via Rho-GTPases, PAK, and ERK1/2. Since migration is a hallmark of astrocyte response during inflammation we propose that, in addition to (or instead of) lowering amyloid-β42 via secretases, ibuprofen and its derivatives may prevent Alzheimer's disease instead of AD by modulating astrocyte reactivity through Rho-GTPase/PAK/ERK-dependent signaling.

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    • "The latter, in addition to tau hyperphosphorylation/aggregation and cognitive impairment9, include an altered cytoskeleton dynamics44, impaired neurogenesis and neuroinflammation21. All the above alterations are reverted to varying extents and with a high degree of specificity compared to other NSAIDs, by CHF5074252627283243. In addition, recent studies indicate the ability of CHF5074 to positively affect CSF biomarkers of neuroinflammation in MCI subjects29, further suggesting that this compound may also act as a microglial modulator capable of reducing pro-inflammatory activity, while promoting the alternative anti-inflammatory and phagocytic state of microglial cells (Porrini et al., AD/PD Conference 2013). "
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    ABSTRACT: Amyloid precursor protein (APP) intracellular domain (AICD) is a product of APP processing with transcriptional modulation activity, whose overexpression causes various Alzheimer's disease (AD)-related dysfunctions. Here we report that 1-(3',4'-dichloro-2-fluoro[1,1'-biphenyl]-4-yl)-cyclopropanecarboxylic acid) (CHF5074), a compound that favorably affects neurodegeneration, neuroinflammation and memory deficit in transgenic mouse models of AD, interacts with the AICD and impairs its nuclear activity. In neuroglioma-APPswe cells, CHF5074 shifted APP cleavage from Aβ42 to the less toxic Aβ38 peptide without affecting APP-C-terminal fragment, nor APP levels. As revealed by photoaffinity labeling, CHF5074 does not interact with γ-secretase, but binds to the AICD and lowers its nuclear translocation. In vivo treatment with CHF5074 reduced AICD occupancy as well as histone H3 acetylation levels and transcriptional output of the AICD-target gene KAI1. The data provide new mechanistic insights on this compound, which is under clinical investigation for AD treatment/prevention, as well as on the contribution of the AICD to AD pathology.
    Full-text · Article · Apr 2014 · Scientific Reports
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    • "Several in vitro and in vivo studies suggest that CHF5074 is able to inhibit brain plaque deposition and intra neuronal A␤, rescue long-term potentiation (LTP) and dendritic spine density alterations, reduce the level of microglial activation and attenuate contextual and spatial memory deficit in different transgenic mouse models of AD [2] [3] [4] [5]. In addition, recent work demonstrated that CHF5074 facilitates axon growth and astrocyte plasticity through the modulation of Rho-GTPase-dependent signaling pathway [6], thus highlighting a multi-modal mechanism of action of this compound. Importantly, CHF5074 appeared to be well tolerated by both wild-type and AD mice, even after prolonged use. "
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    ABSTRACT: CHF5074 is a non-steroidal anti-inflammatory derivative holding disease-modifying potential for the treatment of Alzheimer's disease. The aim of the present study was to characterize the electrophysiological and metabolic profile of CHF5074 in the hippocampus. Electrophysiological recordings show that CHF5074 inhibits in a dose-dependent manner the current-evoked repetitive firing discharge in CA1 pyramidal neurons. This result is paralleled by a dose-dependent reduction of field excitatory post-synaptic potentials with no effect on the paired-pulse ratio. The effects of CHF5074 were not mediated by AMPA or NMDA receptors, since the inward currents induced by local applications of AMPA and NMDA remained constant in the presence of this compound. We also suggest a possible activity of CHF5074 on ASIC1a receptor since ASIC1a-mediated current, evoked by application of a pH 5.5 solution, is reduced by pretreatment with this compound. Moreover, we demonstrate that CHF5074 treatment is able to counteract in hippocampal slices the OGD-induced increase in alanine, lactate and acetate levels. Finally, CHF5074 significantly reduced the apoptosis in hippocampal neurons exposed to OGD, as revealed by cleaved-caspase-3 immunoreactivity and TUNEL staining. Overall, the present work identifies novel mechanisms for CHF5074 in reducing metabolic acidosis, rendering this compound potentially useful also in conditions of brain ischemia.
    Full-text · Article · Mar 2014 · Pharmacological Research
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    • "In line with this view, it has been reported recently that inhibition of lipopolysaccharide-induced γ-secretase activity by DAPT interferes with immune and anti-inflammatory regulatory pathways in the brain [61], while acute DAPT administration restraints microglia activation [62,63]. Recently, it has also been proposed that ibuprofen and its derivatives, including CHF5074, besides reducing Aβ pathology and neuroinflammation, modulate astrocyte reactivity through a Rho-GTPase/PAK/ERK-dependent signalling pathway [23]. In keeping with this purported mode of action, we have previously shown that chronic treatment of Tg2576 mice with CHF5074 causes astrocyte hypertrophy and their accumulation around large Aβ deposits [21] -another mechanism that may contribute to the neuroprotective and functional recovery effects promoted by this compound. "
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    ABSTRACT: Background Alzheimer disease is a multifactorial disorder characterized by the progressive deterioration of neuronal networks. The pathological hallmarks includes extracellular amyloid plaques and intraneuronal neurofibrillary tangles, but the primary cause is only partially understood. Thus, there is growing interest in developing agents that might target multiple mechanisms leading to neuronal degeneration. CHF5074 is a nonsteroidal anti-inflammatory derivative that has been shown to behave as a γ-secretase modulator in vitro and to inhibit plaque deposition and to reverse memory deficit in vivo in transgenic mouse models of Alzheimer’s disease (AD). In the present study, the effects of a long-term (13-month) treatment with CHF5074 on indicators of brain functionality and neurodegeneration in transgenic AD mice (Tg2576) have been assessed and compared with those induced by a prototypical γ-secretase inhibitor (DAPT). Results To this end, plaque-free, 6-month-old Tg2576 mice and wild-type littermates were fed with a diet containing CHF5074 (125 and 375 ppm/day), DAPT (375 ppm/day) or vehicle for 13 months. The measured indicators included object recognition memory, amyloid burden, brain oligomeric and plasma Aβ levels, intraneuronal Aβ, dendritic spine density/morphology, neuronal cyclin A positivity and activated microglia. Tg2576 mice fed with standard diet displayed an impairment of recognition memory. This deficit was completely reverted by the higher dose of CHF5074, while no effects were observed in DAPT-treated mice. Similarly, amyloid plaque burden, microglia activation and aberrant cell cycle events were significantly affected by CHF5074, but not DAPT, treatment. Both CHF5074 and DAPT reduced intraneuronal Aβ content, also increasing Aβ40 and Aβ42 plasma levels. Conclusions This comparative analysis revealed a profoundly diverse range of clinically relevant effects differentiating the multifunctional anti-inflammatory derivative CHF5074 from the γ-secretase inhibitor DAPT and highlighted unique mechanisms and potential targets that may be crucial for neuroprotection in mouse models of AD.
    Full-text · Article · Apr 2013 · BMC Neuroscience
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