Disrupted neuroglial metabolic coupling after peripheral surgery

Immune-related events in the periphery can remotely affect brain function, contributing to neurodegenerative processes and cognitive decline. In mice, peripheral surgery induces a systemic inflammatory response associated with changes in hippocampal synaptic plasticity and transient cognitive decline, however, the underlying mechanisms remain unknown. Here we investigated the effect of peripheral surgery on neuronal-glial function within hippocampal neuronal circuits of relevance to cognitive processing in male mice at 6, 24, and72hpostsurgery. At 6hwedetect theproinflammatorycytokineIL-6inthehippocampus, followedupbyalterations in them RNA and protein expression of astrocyticandneuronal proteinsnecessaryfor optimal energysupplytothebrainandfor thereuptakeandrecycling of glutamate in the synapse. Similarly, at 24 h postsurgery the mRNA expression of structural proteins (GFAP and AQP4) was compromised. At this time point, functional analysis in astrocytes revealed a decrease in resting calcium signaling. Examination of neuronal activity by whole-cell patch-clamp shows elevated levels of glutamatergic transmission and changes in AMPA receptor subunit composition at 72 h postsurgery. Finally, lactate, an essential energy substrate produced by astrocytes and critical for memory formation, decreases at 6 and 72 h after surgery. Based on temporal parallels with our previous studies, we propose that the previously reported cognitive decline observed at 72 h postsurgery in mice might be the consequence of temporal hippocampal metabolic, structural, and functional changes in astrocytes that lead to a disruption of the neuroglial metabolic coupling and consequently to a neuronal dysfunction.This work was supported by a “Ramón y Cajal” fellowship (RYC-2014-15792 to A.G.-C.) from Spanish “Ministerio de Economía y Competitividad”, the Swedish Research Council, the confocal microscope used in the study by Knut and Alice Wallenberg Foundation (Grant KAW2008.0149), and NIH/NIA R01AG057525 to N.T

Nuevas aproximaciones terapéticas para el tratamiento de la Ataxia de Friedreich: HBSP y BDNF

Tesis doctoral inédita, leída en Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 15/07/2013La ataxia de Friedreich (AF) es una enfermedad principalmente neurodegerativa, de herencia autosómica recesiva, con una prevalencia en Europa de 1-2 enfermos por cada 40.000 habitantes. Está causada por una deficiencia en la proteína denominada frataxina, debido mayoritariamente a una mutación de expansión del trinucleótido GAA localizado en el primer intrón del gen. Esta mutación provoca una caída en los niveles de transcripción y por tanto una déficit de proteína funcional que queda por debajo del 25-30% de los niveles normales. En la actualidad existen algunas dudas y controversias acerca de las funciones desempeñadas por la frataxina, y como su deficiencia dispara un proceso neurodegenerativo. En la actualidad la AF no tiene cura. Hemos desarrollado distintos modelos celulares de carácter neuronal de deficiencia de frataxina para la búsqueda de fármacos y genes terapéuticos promotores para el tratamiento de la AF. Estos modelos se basan tanto en células de neuroblastoma diferenciados a células similares a neuronas, cultivos primarios de neuronas de corteza de ratón y células progenitoras neuronales procedentes de biopsias de epitelio mucosa olfativa procedentes de pacientes afectados con AF. En primer lugar hemos observado que el péptido no eritropoyéticos derivado de la eritropoyetina (EPO), denominado HBSP por derivar de la hélice B de la EPO, y recientemente renombrado como ARA290, es capaz, al igual que la EPO, de aumentar los niveles de frataxina, tanto in vitro como in vivo y que parece estar mediado por la vía de Shh. En segundo lugar, hemos realizado una búsqueda de factores de crecimiento con potencial terapéutico en el contexto de la AF, y hemos observado que el factor neurotrófico derivado de cerebro (BDNF; Brain-Derived Neurotrophic factor), así como su análogo 7,8- dihidroxiflavona (7,8-DHF) son capaces de proteger frente a la deficiencia de frataxina, y que además de la activación de vías de señalización de supervivencia también aumentan los niveles de frataxina posiblemente mediante la vía de Shh. Por último, hemos realizado ensayos in vivo de terapia génica con un vector herpesviral portador del gen de BDNF (HSV-BDNF) en ratones en los que hemos inducido una deficiencia de frataxina en el cerebelo, consiguiendo un rescate de los marcadores apoptóticos y de la atrofia de las células de Purkinje, y una mejora significativa en la coordinación motora. En conclusión, nuestros estudios apuntan a nuevas dianas terapéuticas que podrían ser muy prometedoras para el tratamiento de la AF.Friedreich's ataxia (FA) is a mainly neurodegerative autosomal recessive hereditary disease, with a prevalence in Europe of 1-2 patients per 40,000 inhabitants. It is caused by a deficiency in a protein called frataxin, which is mostly due to a GAA trinucleotide expansion located in the first intron of the gene. This mutation causes a decrease in transcrition levels and results in a deficit with functional protein levels below 25-30% of normal levels. At present there are some doubts and controversies about the functional roles performed by frataxin, and how its deficiency triggers a neurodegenerative process. There is no cure for FA. We have developed different neuronal cell models of frataxin deficiency for the search of promising drugs and therapeutic genes for the treatment of FA. These models are based on human neuron-like cells obtained from the differentiation of neuroblastoma cells, mouse primary cortical neurons and stem cells from biopsies of the olfactory mucosa from FA patients. Firstly, we have found that a non erythropoietic peptide derived from erythropoietin (EPO), called HBSP or more recently ARA290, is capable of increasing frataxin levels, both in vitro and in vivo, and that this effect appears to be mediated by the Sonic hedgehog (Shh) pathway. Secondly, we have searched for trophic factors with therapeutic potential in FA. Brainderived neurotrophic factor (BDNF) and its analogue 7,8-dihydroxyflavone (7,8-DHF) can rescue frataxin deficiency by activation of survival signaling pathways. Furthermore, BDNF and 7,8-DHF also increase frataxin levels, a process also involving the Shh pathway. Finally, we have performed an in vivo assay of gene therapy using a herpes viral vector encoding BDNF gene (HSV-BDNF) in mice, where we have induced frataxin deficiency in the cerebellum, obtaining a rescue of apoptotic markers, Purkinje cells, and a significant improvement in the motor coordination of treated mice. In conclusion, our studies point to some new therapeutic targets which may be promising for the treatment of FA

DNA repair pathways are altered in neural cell models of frataxin deficiency

Friedreich's ataxia (FRDA) is a hereditary and predominantly neurodegenerative disease caused by a deficiency of the protein frataxin (FXN). As part of the overall efforts to understand the molecular basis of neurodegeneration in FRDA, a new human neural cell line with doxycycline-induced FXN knockdown was established. This cell line, hereafter referred to as iFKD-SY, is derived from the human neuroblastoma SH-SY5Y and retains the ability to differentiate into mature neuron-like cells. In both proliferating and differentiated iFKD-SY cells, the induction of FXN deficiency is accompanied by increases in oxidative stress and DNA damage, reduced aconitase enzyme activity, higher levels of p53 and p21, activation of caspase-3, and subsequent apoptosis. More interestingly, FXN-deficient iFKD-SY cells exhibit an important transcriptional deregulation in many of the genes implicated in DNA repair pathways. The levels of some crucial proteins involved in DNA repair appear notably diminished. Furthermore, similar changes are found in two additional neural cell models of FXN deficit: primary cultures of FXN-deficient mouse neurons and human olfactory mucosa stem cells obtained from biopsies of FRDA patients. These results suggest that the deficiency of FXN leads to a down-regulation of DNA repair pathways that synergizes with oxidative stress to provoke DNA damage, which may be involved in the pathogenesis of FRDA. Thus, a failure in DNA repair may be considered a shared common molecular mechanism contributing to neurodegeneration in a number of hereditary ataxias including FRDA.Spanish National Research Plan (SAF2012-38042 and SAF2015-69361-R) and the Autonomous Government of Madrid (Comunidad Aut´onoma de Madrid, CAM (S2010/BMD-2331)). S.P.-L. was supported by the Centre for Biomedical Network Research on Rare Diseases (Centro de Investigación Biomédica en Red sobre Enfermedades Raras, CIBERER). J.M.-L was supported by a fellowship from the Spanish Ministry of Science and Innovation (FPI AP2007-00896

Absence of TXNIP in humans leads to lactic acidosis and low serum methionine linked to deficient respiration on pyruvate

Thioredoxin-interacting protein (TXNIP) is an a-arrestin that can bind to and inhibit the antioxidant protein thioredoxin (TXN). TXNIP expression is induced by glucose and promotes b-cell apoptosis in the pancreas, and deletion of its gene in mouse models protects against diabetes. TXNIP is currently studied as a potential new target for antidiabetic drug therapy. In this study, we describe a family with a mutation in the TXNIP gene leading to nondetectable expression of TXNIP protein. Symptoms of affected family members include lactic acidosis and low serum methionine levels. Using patient-derived TXNIP-deficient fibroblasts and myoblasts, we show that oxidative phosphorylation is impaired in these cells when given glucose and pyruvate but normalized with malate. Isolated mitochondria from these cells appear to have normal respiratory function. The cells also display a transcriptional pattern suggestive of a high basal activation of the Nrf2 transcription factor. We conclude that a complete lack of TXNIP in human is nonlethal and leads to specific metabolic distortions that are, at least in part, linked to a deficient respiration on pyruvate. The results give important insights into the impact of TXNIP in humans and thus help to further advance the development of antidiabetic drugs targeting this protein.“Ministerio of Economía y Competitividad” (grant BFU2016-77634-R and “Ramón y Cajal” fellowship RYC-2014-15792), Diabetesfonden, and Alicia Koplowitz Foundation to A.G.-C. A.Wr. is a Ragnar Söderberg fellow in Medicine (M77/13

Altered Secretome and ROS Production in Olfactory Mucosa Stem Cells Derived from Friedreich’s Ataxia Patients

© 2020 by the authors.Friedreich’s ataxia is the most common hereditary ataxia for which there is no cure or approved treatment at present. However, therapeutic developments based on the understanding of pathological mechanisms underlying the disease have advanced considerably, with the implementation of cellular models that mimic the disease playing a crucial role. Human olfactory ecto-mesenchymal stem cells represent a novel model that could prove useful due to their accessibility and neurogenic capacity. Here, we isolated and cultured these stem cells from Friedreich´s ataxia patients and healthy donors, characterizing their phenotype and describing disease-specific features such as reduced cell viability, impaired aconitase activity, increased ROS production and the release of cytokines involved in neuroinflammation. Importantly, we observed a positive effect on patient-derived cells, when frataxin levels were restored, confirming the utility of this in vitro model to study the disease. This model will improve our understanding of Friedreich´s ataxia pathogenesis and will help in developing rationally designed therapeutic strategies.This work was supported by grants of the Spanish National Research Plan (SAF 2015–69361-R), L’association Française de l’Ataxie de Friedreich and Fundación Ataxia en Movimiento. Frida Loria received funding from the Marie Skłodowska-Curie Action COFUND 2015 (EU project 713366—InterTalentum).Peer reviewe

Altered secretome and ros production in olfactory mucosa stem cells derived from friedreich's ataxia patients

Friedreich’s ataxia is the most common hereditary ataxia for which there is no cure or approved treatment at present. However, therapeutic developments based on the understanding of pathological mechanisms underlying the disease have advanced considerably, with the implementation of cellular models that mimic the disease playing a crucial role. Human olfactory ecto-mesenchymal stem cells represent a novel model that could prove useful due to their accessibility and neurogenic capacity. Here, we isolated and cultured these stem cells from Friedreich´s ataxia patients and healthy donors, characterizing their phenotype and describing disease-specific features such as reduced cell viability, impaired aconitase activity, increased ROS production and the release of cytokines involved in neuroinflammation. Importantly, we observed a positive e ect on patient-derived cells, when frataxin levels were restored, confirming the utility of this in vitro model to study the disease. This model will improve our understanding of Friedreich´s ataxia pathogenesis and will help in developing rationally designed therapeutic strategies.Spanish National Research Plan (SAF 2015–69361-R), L’association Française de l’Ataxie de Friedreich and Fundación Ataxia en Movimiento. Frida Loria received funding from the Marie Skłodowska-Curie Action COFUND 201