title: Interplay between TDP-43 and docosahexaenoic acid-related processes in amyotrophic lateral sclerosis.
abstract: BACKGROUND
  Docosahexaenoic acid (DHA), a key lipid in nervous system homeostasis, is depleted in the spinal cord of sporadic amyotrophic lateral sclerosis (sALS) patients. However, the basis for such loss was unknown.
  
  
  METHODS
  DHA synthetic machinery was evaluated in spinal cord samples from ALS patients and controls by immunohistochemistry and western blot. Further, lipid composition was measured in organotypic spinal cord cultures by gas chromatography and liquid chromatography coupled to mass spectrometry. In these samples, mitochondrial respiratory functions were measured by high resolution respirometry. Finally, Neuro2-A and stem cell-derived human neurons were used for evaluating mechanistic relationships between TDP-43 aggregation, oxidative stress and cellular changes in DHA-related proteins.
  
  
  RESULTS
  ALS is associated to changes in the spinal cord distribution of DHA synthesis enzymatic machinery comparing ten ALS cases and eight controls. We found increased levels of desaturases (ca 95% increase, p<0.001), but decreased amounts of DHA-related β-oxidation enzymes in ALS samples (40% decrease, p<0.05). Further, drebrin, a DHA-dependent synaptic protein, is depleted in spinal cord samples from ALS patients (around 40% loss, p<0.05). In contrast, chronic excitotoxicity in spinal cord increases DHA acid amount, with both enhanced concentrations of neuroprotective docosahexaenoic acid-derived resolvin D, and higher lipid peroxidation-derived molecules such as 8-iso-prostaglandin-F2-α (8-iso-PGF2α) levels. Since α-tocopherol improved mitochondrial respiratory function and motor neuron survival in these conditions, it is suggested that oxidative stress could boost motor neuron loss. Cell culture and metabolic flux experiments, showing enhanced expression of desaturases (FADS2) and β-oxidation enzymes after H2O2 challenge suggest that DHA production can be an initial response to oxidative stress, driven by TDP-43 aggregation and drebrin loss. Interestingly, these changes were dependent on cell type used, since human neurons exhibited losses of FADS2 and drebrin after oxidative stress. These features (drebrin loss and FADS2 alterations) were also produced by transfection by aggregation prone C-terminal fragments of TDP-43.
  
  
  CONCLUSIONS
  sALS is associated with tissue-specific DHA-dependent synthetic machinery alteration. Furthermore, excitotoxicity sinergizes with oxidative stress to increase DHA levels, which could act as a response over stress, involving the expression of DHA synthetic enzymes. Later on, this allostatic overload could exacerbate cell stress by contributing to TDP-43 aggregation. This, at its turn, could blunt this protective response, overall leading to DHA depletion and neuronal dysfunction.
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: dcacabelos@mex.udl.cat.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cacabelos
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: victoria.ayala@mex.udl.cat.
authors.forename: Victòria
authors.initials: V
authors.lastname: Ayala
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: anabgs@mex.udl.cat.
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Granado-Serrano
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: mariona.jove@udl.cat.
authors.forename: Mariona
authors.initials: M
authors.lastname: Jové
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: pascual.tc92@gmail.com.
authors.forename: Pascual
authors.initials: P
authors.lastname: Torres
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: jboada@mex.udl.cat.
authors.forename: Jordi
authors.initials: J
authors.lastname: Boada
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: rosanna.cabre@mex.udl.cat.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Cabré
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: omar.ramirez78@mex.udl.cat.
authors.forename: Omar
authors.initials: O
authors.lastname: Ramírez-Núñez
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: hugonzalo@gmail.com.
authors.forename: Hugo
authors.initials: H
authors.lastname: Gonzalo
authors.affiliation: Departament de Tecnologia d'Aliments, XaRTA-TPV, Escola Tècnica Superior d' Enginyeria Agrària, UdL, Avda Rovira Roure, 85, 25008 Lleida, Spain. Electronic address: asocan@hotmail.com.
authors.forename: Aranzazu
authors.initials: A
authors.lastname: Soler-Cantero
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: jceserrano@mex.udl.cat.
authors.forename: José Carlos Enrique
authors.initials: JC
authors.lastname: Serrano
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: mjosep.bellmunt@cmb.udl.cat.
authors.forename: Maria Josep
authors.initials: MJ
authors.lastname: Bellmunt
authors.affiliation: Departament de Tecnologia d'Aliments, XaRTA-TPV, Escola Tècnica Superior d' Enginyeria Agrària, UdL, Avda Rovira Roure, 85, 25008 Lleida, Spain. Electronic address: maripaz@tecal.udl.cat.
authors.forename: María Paz
authors.initials: MP
authors.lastname: Romero
authors.affiliation: Departament de Tecnologia d'Aliments, XaRTA-TPV, Escola Tècnica Superior d' Enginyeria Agrària, UdL, Avda Rovira Roure, 85, 25008 Lleida, Spain. Electronic address: motilva@tecal.udl.cat.
authors.forename: María José
authors.initials: MJ
authors.lastname: Motilva
authors.affiliation: Department of Neuropathology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan. Electronic address: nonaka-tk@igakuken.or.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nonaka
authors.affiliation: Departament de Tecnologia d'Aliments, XaRTA-TPV, Escola Tècnica Superior d' Enginyeria Agrària, UdL, Avda Rovira Roure, 85, 25008 Lleida, Spain. Electronic address: hasegawa-ms@igakuken.or.jp.
authors.forename: Masato
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Institut de Neuropatologia, Hospital Universitari de Bellvitge - IDIBELL, Universitat de Barcelona, Spain; CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), Instituto Carlos III, Spanish Ministry of Health, Spain. L'Hospitalet de Llobregat, c/La Feixa Llarga, S/N 08908 Hospitalet de Llobregat, Barcelona, Spain. Electronic address: 8082ifa@gmail.com.
authors.forename: Isidre
authors.initials: I
authors.lastname: Ferrer
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: reinald.pamplona@mex.udl.cat.
authors.forename: Reinald
authors.initials: R
authors.lastname: Pamplona
authors.affiliation: Departament de Medicina Experimental, Facultat de Medicina, IRBLLEIDA-UDL, Avda Rovira Roure, 44, 25008 Lleida, Spain. Electronic address: manuel.portero@mex.udl.cat.
authors.forename: Manuel
authors.initials: M
authors.lastname: Portero-Otín
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000201:enzymology / Q000473:pathology*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004281:Docosahexaenoic Acids / Q000378:metabolism* / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D028361:Mitochondrial Diseases / Q000378:metabolism / Q000473:pathology; D009447:Neuroblastoma / Q000473:pathology; D016877:Oxidants / Q000494:pharmacology; D051381:Rats; D013116:Spinal Cord / Q000378:metabolism*; D013234:Stem Cells / Q000187:drug effects / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D005227:Fatty Acids; D016877:Oxidants; C000598624:TARDBP protein, human; D004281:Docosahexaenoic Acids; D006861:Hydrogen Peroxide
keywords: Lipidomic; Mitochondria; Motor neuron; Oxidative stress; Polyunsaturated fatty acids; TDP-43