Suchergebnisse

Cognitive decline in Alzheimer's disease (AD) is highly related to synaptic dysfunction and neuronal loss. In AD, the hyperphosphorylation of tau compromises axonal transport and leads to the generation of dystrophic neurites, contributing to synaptic impairment. In addition to phospho-tau, AD brains accumulate amyloid-beta. This study evaluated the effect of the brain-penetrant microtubule-stabilizing agent, Epothilone D (EpoD) in the progression of the disease in a double transgenic mouse model of amyloidosis. Young APP/PS1 mice were weekly treated with intraperitoneal injections of EpoD (2 mg/kg) or vehicle solution for 3 months. Memory performance was tested using object-recognition tasks, Y-maze and Morris water maze. EpoD-treated mice improved their performance of cognitive tests, while hippocampal phospho-tau and Aβ levels, especially soluble oligomers, decreased significantly. β/γ-secretase activities were not affected by EpoD in vitro. A significant amelioration of synaptic/neuritic pathology was found. Remarkably, EpoD exerted a neuroprotective effect on SOM-interneurons, a highly AD-vulnerable GABAergic subpopulation. In conclusion, EpoD improved microtubule dynamics and axonal transport in an AD-like context, reducing tau and Abeta accumulation, and promoting neuronal and cognitive protection. These results underline the crosstalk between cytoskeleton pathology and proteinopathy. Therefore, microtubule-stabilizing drugs could be candidates for slowing AD progression at both tau and Aβ pathologies. ; Supported by PI18/01557 (to AG) and PI18/01556 (to JV) grants from ISCiii of Spain, co-financed by FEDER funds from European Union, CIBERNED collaborative grant (to AG and JV), and by PPIT.UMA.B1.2017/26 grant (to RSV). Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

Neuronal loss is the best neuropathological substrate that correlates with cortical atrophy and dementia in Alzheimer's disease (AD). Defective GABAergic neuronal functions may lead to cortical network hyperactivity and aberrant neuronal oscillations and in consequence, generate a detrimental alteration in memory processes. In this study, using immunohistochemical and stereological approaches, we report that the two major and non‐overlapping groups of inhibitory interneurons (SOM‐cells and PV‐cells) displayed distinct vulnerability in the perirhinal cortex of APP/PS1 mice and AD patients. SOM‐positive neurons were notably sensitive and exhibited a dramatic decrease in the perirhinal cortex of 6‐month‐old transgenic mice (57% and 61% in areas 36 and 35, respectively) and, most importantly, in AD patients (91% in Braak V–VI cases). In addition, this interneuron degenerative process seems to occur in parallel, and closely related, with the progression of the amyloid pathology. However, the population expressing PV was unaffected in APP/PS1 mice while in AD brains suffered a pronounced and significant loss (69%). As a key component of cortico‐hippocampal networks, the perirhinal cortex plays an important role in memory processes, especially in familiarity‐based memory recognition. Therefore, disrupted functional connectivity of this cortical region, as a result of the early SOM and PV neurodegeneration, might contribute to the altered brain rhythms and cognitive failures observed in the initial clinical phase of AD patients. Finally, these findings highlight the failure of amyloidogenic AD models to fully recapitulate the selective neuronal degeneration occurring in humans. ; This study was supported by Instituto de Salud Carlos III (ISCiii) of Spain, co‐financed by FEDER funds from European Union, through grants PI18/01557 (to AG) and PI18/01556 (to JV), and CIBERNED (to AG and JV), by Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucia Proyecto de Excelencia (CTS‐2035) (to JV and AG); by Malaga University grant PPIT.UMA.B1.2017/26 (to RSV). CND and JJFV were supported by FPI (Junta Andalucía) and FPU (Spanish Ministry of Science, Innovation and Universities) PhD fellowships, respectively. MMO held a Garantia Juvenil (Junta Andalucia) contract. RSV and JAGL held a postdoctoral contract from the University of Malaga, and AGA from CIBERNED. ; Peer reviewed

In Alzheimer's disease (AD), and other tauopathies, microtubule destabilization compromises axonal and synaptic integrity contributing to neurodegeneration. These diseases are characterized by the intracellular accumulation of hyperphosphorylated tau leading to neurofibrillary pathology. AD brains also accumulate amyloid-beta (Aβ) deposits. However, the effect of microtubule stabilizing agents on Aβ pathology has not been assessed so far. Here we have evaluated the impact of the brain-penetrant microtubule-stabilizing agent Epothilone D (EpoD) in an amyloidogenic model of AD. Three-month-old APP/PS1 mice, before the pathology onset, were weekly injected with EpoD for 3 months. Treated mice showed significant decrease in the phospho-tau levels and, more interesting, in the intracellular and extracellular hippocampal Aβ accumulation, including the soluble oligomeric forms. Moreover, a significant cognitive improvement and amelioration of the synaptic and neuritic pathology was found. Remarkably, EpoD exerted a neuroprotective effect on SOM-interneurons, a highly AD-vulnerable GABAergic subpopulation. Therefore, our results suggested that EpoD improved microtubule dynamics and axonal transport in an AD-like context, reducing tau and Aβ levels and promoting neuronal and cognitive protection. These results underline the existence of a crosstalk between cytoskeleton pathology and the two major AD protein lesions. Therefore, microtubule stabilizers could be considered therapeutic agents to slow the progression of both tau and Aβ pathology. ; This study was supported by Instituto de Salud Carlos III (ISCiii) of Spain, co-financed by FEDER funds from European Union, through grants PI15/00796 and PI18/01557 (both to AG), PI15/00957 and PI18/01556 (both to JV), and CIBERNED (CB06/05/1116 to AG and CB06/05/0094 to JV); by Malaga University grant PPIT.UMA.B1.2017/26 (to RSV). JJFV and CMC were supported by FPU PhD fellowships (Spanish Ministry of Science, Innovation and Universities). RSV held a postdoctoral contract from Malaga University. IMG is recipient of a senior postdoctoral contract from Ramon y Cajal Program (Spain Government).

Alzheimer's disease (AD) constitutes the most prominent form of dementia among elderly individuals worldwide. Disease modeling using murine transgenic mice was first initiated thanks to the discovery of heritable mutations in amyloid precursor protein (APP) and presenilins (PS) genes. However, due to the repeated failure of translational applications from animal models to human patients, along with the recent advances in genetic susceptibility and our current understanding on disease biology, these models have evolved over time in an attempt to better reproduce the complexity of this devastating disease and improve their applicability. In this review, we provide a comprehensive overview about the major pathological elements of human AD (plaques, tauopathy, synaptic damage, neuronal death, neuroinflammation and glial dysfunction), discussing the knowledge that available mouse models have provided about the mechanisms underlying human disease. Moreover, we highlight the pros and cons of current models, and the revolution offered by the concomitant use of transgenic mice and omics technologies that may lead to a more rapid improvement of the present modeling batter ; This research was funded by INSTITUTO DE SALUD CARLOS III (ISCiii) of Spain, cofinanced by FEDER funds from European Union, through grants PI21/00915 (to AG) and PI21/00914 (to JV); by JUNTA DE ANDALUCIA CONSEJERÍA DE ECONOMÍA Y CONOCIMIENTO through grants UMA18-FEDERJA-211 (to AG), UMA20-FEDERJA-104 (to IMG), P18-RT-2233 (to AG) and US-1262734 (to JV) co-financed by Programa Operativo FEDER 2014–2020 and CONSEJERIA DE SALUD grant PI-0276-2018 (to JAGL); by SPANISH MINISTER OF SCIENCE AND INNOVATION grant PID2019-108911RA-100 (to DBV), BEATRIZ GALINDO PROGRAM BAGAL18/00052 (to DBV), Alzheimer Association AARG-22-928219 (to DBV), grant PID2019-107090RA-100 (to IMG) and RAMON Y CAJAL PROGRAM RYC-2017-21879 (to IMG); and by MALAGA UNIVERSITY grant B1-2019_07 (to ESM), grant B1-2020_04 (to JAGL), grant B1-2019_06 (to IMG) and NASARD grant 27565 2018 (to ...