title: Monocytes of patients with amyotrophic lateral sclerosis linked to gene mutations display altered TDP-43 subcellular distribution.
abstract: OBJECTIVE
  Cytoplasmic accumulation of the nuclear protein transactive response DNA-binding protein 43 (TDP-43) is an early determinant of motor neuron degeneration in most amyotrophic lateral sclerosis (ALS) cases. We previously disclosed this accumulation in circulating lymphomonocytes (CLM) of ALS patients with mutant TARDBP, the TDP-43-coding gene, as well as of a healthy individual carrying the parental TARDBP mutation. Here, we investigate TDP-43 subcellular localization in CLM and in the constituent cells, lymphocytes and monocytes, of patients with various ALS-linked mutant genes.
  
  
  METHODS
  TDP-43 subcellular localization was analysed with western immunoblotting and immunocytofluorescence in CLM of healthy controls (n = 10), patients with mutant TARDBP (n = 4, 1 homozygous), valosin-containing protein (VCP; n = 2), fused in sarcoma/translocated in liposarcoma (FUS; n = 2), Cu/Zn superoxide dismutase 1 (SOD1; n = 6), chromosome 9 open reading frame 72 (C9ORF72; n = 4), without mutations (n = 5) and neurologically unaffected subjects with mutant TARDBP (n = 2).
  
  
  RESULTS
  TDP-43 cytoplasmic accumulation was found (P < 0.05 vs. controls) in CLM of patients with mutant TARDBP or VCP, but not FUS, in line with TDP-43 subcellular localization described for motor neurons of corresponding groups. Accumulation also characterized CLM of the healthy individuals with mutant TARDBP and of some patients with mutant SOD1 or C9ORF72. In 5 patients, belonging to categories described to carry TDP-43 mislocalization in motor neurons (3 C9ORF72, 1 TARDBP and 1 without mutations), TDP-43 cytoplasmic accumulation was not detected in CLM or in lymphocytes but was in monocytes.
  
  
  CONCLUSIONS
  In ALS forms characterized by TDP-43 mislocalization in motor neurons, monocytes display this alteration, even when not manifest in CLM. Monocytes may be used to support diagnosis, as well as to identify subjects at risk, of ALS and to develop/monitor targeted treatments.
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.
authors.forename: G
authors.identifier: http://orcid.org/0000-0002-3966-8695
authors.initials: G
authors.lastname: De Marco
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Lomartire
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.|ALS Center, University of Turin and AOU Città della Salute e della Scienza, Turin, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Calvo
authors.affiliation: Molecular Biotechnology Center, University of Turin, Turin, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Risso
authors.affiliation: Molecular Biotechnology Center, University of Turin, Turin, Italy.
authors.forename: E
authors.initials: E
authors.lastname: De Luca
authors.affiliation: Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Mostert
authors.affiliation: Department of Neuroscience, Sant'Agostino Estense Hospital, University of Modena, Modena, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Mandrioli
authors.affiliation: Department of Neurosciences, Ophthalmology, Genetics, Rehabilitation and Child Health, IRCCS AOU San Martino IST, University of Genoa, Genoa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Caponnetto
authors.affiliation: Department of Neurology, AOU and University of Cagliari, Cagliari, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Borghero
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.|ALS Center, University of Turin and AOU Città della Salute e della Scienza, Turin, Italy.
authors.forename: U
authors.initials: U
authors.lastname: Manera
authors.affiliation: ALS Center, University of Turin and AOU Città della Salute e della Scienza, Turin, Italy.|Department of Neurosciences, Ophthalmology, Genetics, Rehabilitation and Child Health, IRCCS AOU San Martino IST, University of Genoa, Genoa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Canosa
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.|ALS Center, University of Turin and AOU Città della Salute e della Scienza, Turin, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Moglia
authors.affiliation: Molecular Genetics Unit, Department of Clinical Pathology, AOU Città della Salute e della Scienza, University of Turin, Turin, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Restagno
authors.affiliation: Department of Neuroscience, Sant'Agostino Estense Hospital, University of Modena, Modena, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Fini
authors.affiliation: Clinical Hemato-Oncology, European Institute of Oncology (IEO), Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Tarella
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.
authors.forename: M T
authors.initials: MT
authors.lastname: Giordana
authors.affiliation: Department of Oncology, University of Turin, Turin, Italy.
authors.forename: M T
authors.initials: MT
authors.lastname: Rinaudo
authors.affiliation: 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy.|ALS Center, University of Turin and AOU Città della Salute e della Scienza, Turin, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Chiò
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D009154:Mutation
chemical_list: D004268:DNA-Binding Proteins; C000598624:TARDBP protein, human
keywords: amyotrophic lateral sclerosis; gene mutations; monocytes; transactive response DNA-binding protein 43 subcellular localization