Journal of Molecular Neuroscience

, Volume 64, Issue 4, pp 611–618 | Cite as

The Potential Role of Toll-Like Receptor 4 in Mediating Dopaminergic Cell Loss and Alpha-Synuclein Expression in the Acute MPTP Mouse Model of Parkinson’s Disease

  • Giuseppina Mariucci
  • Rita Pagiotti
  • Francesco Galli
  • Luigina Romani
  • Carmela Conte


Toll-like receptors (TLRs) may have a role in Parkinson’s disease (PD). In this study, we aimed at investigating the dopaminergic cell loss and alpha-synuclein (α-SYN) expression in TLR4-deficient mice (TLR4−/−) acutely exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a pharmacological PD model. TLR4 ablation restrained the number of dopaminergic neurons in the substantia nigra (SN), as assessed by tyrosine hydroxylase (TH) protein expression. Intriguingly, TLR4−/− mice showed massive α-SYN protein accumulation in the midbrain along with high α-SYN mRNA levels in cerebral cortex, striatum, hippocampus, and cerebellum. Contrary to expectations, the high levels of α-SYN do not correlate with greater dopaminergic neuronal loss. The levels of nigral α-SYN protein in TLR4−/− mice further, but not significantly, increased during MPTP treatment. Contrariwise, MPTP treatment significantly induced the mRNA expression of α-SYN in examined brain regions of WT and TLR4−/− mice. Protein levels of GATA2, a transcription factor proposed to control α-SYN gene expression, did not change in TLR4−/− mice at baseline and after MPTP treatment. These findings suggest a role for TLR4 in mediating dopaminergic cell loss and in the constitutive expression of brain α-SYN. However, further exploration is needed in order to establish the actual role of α-SYN in the relative absence of TLR4.


Parkinson’s disease Toll-like receptor 4 Thyrosine hydroxylase Alpha-synuclein GATA2 







Central nervous system


Central nervous system




Danger-associated molecular patterns


Pathogen-associated molecular patterns


Multiple system atrophy




Parkinson’s disease


Pattern recognition receptors


Substantia nigra


Substantia nigra pars compacta


Toll-like receptors


Tyrosine hydroxylase


TLR4-deficient mice


Wild-type mice



We thank Prof Luigina Romani (University of Perugia) for the generous gift of TLR4−/− mice.

This study was supported by grants from the Fondazione Cassa di Risparmio di Perugia for Scientific and Technological Research (no. 2016.0031.021) and from the University of Perugia (Ricerca di base 2014; Ricerca di base 2015).

Compliance with Ethical Standards

Experiments were performed according to the Italian Approved Animal Welfare Assurance 245-2011-B

Conflict of Interest

The authors declare that they have no conflict of interest.


  1. Addis MF, Tanca A, Pagnozzi D, Crobu S, Fanciulli G, Cossu-Rocca P, Uzzau S (2009) Generation of high-quality protein extracts from formalin-fixed, paraffin-embedded tissues. Proteomics 9:3815–3823CrossRefPubMedGoogle Scholar
  2. Arroyo DS, Soria JA, Gaviglio EA, Rodriguez-Galan MC, Iribarren P (2011) Toll-like receptors are key players in neurodegeneration. Int Immunopharmacol 11:1415–1421. CrossRefPubMedPubMedCentralGoogle Scholar
  3. Bartels T, Choi JG, Selkoe DJ (2011) α-Synuclein occurs physiologically as a helically folded tetramer that resists aggregation. Nature 477:107–110. CrossRefPubMedPubMedCentralGoogle Scholar
  4. Brenner S, Wersinger C, Gasser T (2015) Transcriptional regulation of the α-synuclein gene in human brain tissue. Neurosci Lett 599:140–145. CrossRefPubMedGoogle Scholar
  5. Carty M, Bowie AG (2011) Evaluating the role of toll-like receptors in diseases of the central nervous system. Biochem Pharmacol 81:825–837. CrossRefPubMedGoogle Scholar
  6. Caso JR, Pradillo JM, Hurtado O, Lorenzo P, Moro MA, Lizasoain I (2007) Toll-like receptor 4 is involved in brain damage and inflammation after experimental stroke. Circulation 115:1599–2608. CrossRefPubMedGoogle Scholar
  7. Chao Y, Wong SC, Tan EK (2014) Evidence of inflammatory system involvement in Parkinson’s disease. Biomed Res Int 2014(308654):1–9. Google Scholar
  8. Conte C, Roscini L, Sardella R, Mariucci G, Scorzoni S, Beccari T, Corte L (2017) Toll like receptor 4 affects the cerebral biochemical changes induced by MPTP treatment. Neurochem Res 42:493–500. CrossRefPubMedGoogle Scholar
  9. Drouin-Ouellet J, St-Amour I, Saint-Pierre M, Lamontagne-Proulx J, Kriz J, Barker RA, Cicchetti F (2015) Toll-like receptor expression in the blood and brain of patients and a mouse model of Parkinson’s disease. Int J Neuropsychopharmacol 18:1–15. doi:
  10. El-Agnaf OM, Salem SA, Paleologou KE, Cooper LJ, Fullwood NJ, Gibson MJ, Curran MD, Court JA, Mann DM, Ikeda S, Cookson MR, Hardy J, Allsop D (2003) Alpha-synuclein implicated in Parkinson’s disease is present in extracellular biological fluids, including human plasma. FASEB J 17:1945–1947. CrossRefPubMedGoogle Scholar
  11. Fahn S, Przedborski S (2005) Parkinsonism. In: Rowland LP (ed) Merritt’s neurology. Lippincott Williams & Wilkins, New York, pp 828–846Google Scholar
  12. Fellner L, Irschick R, Schanda K, Reind M, Klimaschewski L, Poewe W, Wenning GK, Stefanova N (2013) Toll-like receptor 4 is required for α-synuclein dependent activation of microglia and astroglia. Glia 61:349–360. CrossRefPubMedPubMedCentralGoogle Scholar
  13. Halliday GM, Stevens CH (2011) Glia: initiators and progressors of pathology in Parkinson’s disease. Mov Disord 26:6–17. CrossRefPubMedGoogle Scholar
  14. Hirsch EC, Hunot S (2009) Neuroinflammation in Parkinson’s disease: a target for neuroprotection? Lancet Neurol 8:382–397. CrossRefPubMedGoogle Scholar
  15. Iwai A, Masliah E, Yoshimoto M, Ge N, Flanagan L, de Silva HA, Kittel A, Saitoh T (1995) The precursor protein of non-a beta component of Alzheimer’s disease amyloid is a presynaptic protein of the central nervous system. Neuron 14:467–475. CrossRefPubMedGoogle Scholar
  16. Jellinger KA (2012) Neuropathology of sporadic Parkinson’s disease: evaluation and changes of concepts. Mov Disord 27:8–30. ReviewCrossRefPubMedGoogle Scholar
  17. Kaisho T, Akira S (2004) Pleiotropic function of toll-like receptors. Microbes Infect 6:1388–1394. CrossRefPubMedGoogle Scholar
  18. Konat GW, Kielian T, Marriott I (2006) The role of toll-like receptors in CNS response to microbial challenge. J Neurochem 99:1–12. CrossRefPubMedPubMedCentralGoogle Scholar
  19. Kong Y, Le Y (2011) Toll-like receptors in inflammation of the central nervous system. Int Immunopharmacol 11:1407–1414. CrossRefPubMedGoogle Scholar
  20. Lashuel HA, Overk CR, Oueslati A, Masliah E (2013) The many faces of α-synuclein: from structure and toxicity to therapeutic target. Nat Rev Neurosci 14:38–48. CrossRefPubMedPubMedCentralGoogle Scholar
  21. Lee HJ, Patel S, Lee SJ (2005) Intravesicular localization and exocytosis of alpha-synuclein and its aggregates. J Neurosci 25:6016–6024. CrossRefPubMedGoogle Scholar
  22. Lehnardt S, Massillon L, Follett P, Jensen FE, Ratan R, Rosenberg PA, Volpe JJ, Vartanian T (2003) Activation of innate immunity in the CNS triggers neurodegeneration through a toll-like receptor 4-dependent pathway. Proc Natl Acad Sci U S A 100:8514–8519. CrossRefPubMedPubMedCentralGoogle Scholar
  23. Letiembre M, Liu Y, Walter S, Hao W, Pfander T, Wrede A, Schulz-Schaeffer W, Fassbender K (2009) Screening of innate immune receptors in neurodegenerative diseases: a similar pattern. Neurobiol Aging 30:759–768. CrossRefPubMedGoogle Scholar
  24. Marques O, Outeiro TF (2012) Alpha-synuclein: from secretion to dysfunction and death. Cell Death Dis 3:e350. CrossRefPubMedPubMedCentralGoogle Scholar
  25. Mogensen TH (2009) Pathogen recognition and inflammatory signaling in innate immune defenses. Clin Microbiol Rev 22:240–273. CrossRefPubMedPubMedCentralGoogle Scholar
  26. Noelker C, Morel L, Lescot T, Osterloh A, Alvarez-Fischer D, Breloer M, Henze C, Depboylu C, Skrzydelski D, Michel PP, Dodel RC, Lu L, Hirsch EC, Hunot S, Hartmann A (2013) Toll like receptor 4 mediates cell death in a mouse MPTP model of Parkinson disease. Sci Rep 3:1393. CrossRefPubMedPubMedCentralGoogle Scholar
  27. Norris EH, Giasson BI, Lee VM (2004) Alpha-synuclein: normal function and role in neurodegenerative diseases. Curr Top Dev Biol 60:17–54. CrossRefPubMedGoogle Scholar
  28. Okun E, Griffioen KJ, Lathia JD, Tang SC, Mattson MP, Arumugam TV (2009) Toll-like receptors in neurodegeneration. Brain Res Rev 59:278–292. CrossRefPubMedGoogle Scholar
  29. Owens T (2005) Toll-like receptors on astrocytes: patterning for immunity. J Neuroimmunol 159(1–2):1–2. CrossRefPubMedGoogle Scholar
  30. Panaro MA, Lofrumento DD, Saponaro C, De Nuccio F, Cianciulli A, Mitolo V, Nicolardi G (2008) Expression of TLR4 and CD14 in the central nervous system (CNS) in a MPTP mouse model of Parkinson’s-like disease. Immunopharmacol Immunotoxicol 30:729–740. CrossRefPubMedGoogle Scholar
  31. Pasare C, Medzhitov R (2003) Toll-like receptors: balancing host resistance with immune tolerance. Curr Opin Immunol 15:677–682. CrossRefPubMedGoogle Scholar
  32. Paxinos G, Franklin KBJ (2001) A multimodal, multidimensional atlas of the C57BL/6J mouse brain. In: The mouse brain in stereotaxic coordinates, 2nd edn. Academic Press, San Diego. Google Scholar
  33. Piccinini AM, Midwood KS (2010) DAMPening inflammation by modulating TLR signaling. Mediat Inflamm 2010:1–21. CrossRefGoogle Scholar
  34. Ros-Bernal F, Hunot S, Herrero MT, Parnadeau S, Corvol JC, Luc L, Alvarez-Fischer D, Carrillo-de Sauvage MA, Saurini F, Coussieu C, Kinugawa K, Prigent A, Höglinger G, Hamon M, Tronche F, Hirsch EC, Vyas S (2011) Microglial glucocorticoid receptors play a pivotal role in regulating dopaminergic neurodegeneration in parkinsonism. Proc Natl Acad Sci U S A 108:6632–6637. CrossRefPubMedPubMedCentralGoogle Scholar
  35. Scherzer CR, Grass JA, Liao Z, Pepivani I, Zheng B, Eklund AC, Ney PA, Ng J, McGoldrick M, Mollenhauer B, Bresnick EH, Schlossmacher MG (2008) GATA transcription factors directly regulate the Parkinson’s disease-linked gene alpha-synuclein. Proc Natl Acad Sci U S A 105:10907–10912. CrossRefPubMedPubMedCentralGoogle Scholar
  36. Shults CW (2006) Lewy bodies. Proc Natl Acad Sci U S A 103:1661–1668. CrossRefPubMedPubMedCentralGoogle Scholar
  37. Spillantini MG, Schmidt ML, Lee VM, Trojanowski JQ, Jakes R, Goedert M (1997) Alpha-synuclein in Lewy bodies. Nature 388:839–840. CrossRefPubMedGoogle Scholar
  38. Stefanova N, Reind M, Neumann M, Kahle PJ, Poewe W, Wenning GK (2007) Microglial activation mediates neurodegeneration related to oligodendroglial alpha synucleinopathy: implications for multiple system atrophy. Mov Disord 22:2196–2203. CrossRefPubMedGoogle Scholar
  39. Stefanova N, Fellner L, Reind M, Masliah E, Poewe W, Wenning GK (2011) Toll-like receptor 4 promotes α-synuclein clearance and survival of nigral dopaminergic neurons. Am J Pathol 179:954–963. CrossRefPubMedPubMedCentralGoogle Scholar
  40. Su X, Maguire-Zeiss KA, Giuliano R, Prifti L, Venkatesh K, Federoff HJ (2008) Synuclein activates microglia in a model of Parkinson’s disease. Neurobiol Aging 29:1690–1701. CrossRefPubMedGoogle Scholar
  41. Tang SC, Arumugam TV, Xu X, Cheng A, Mughal MR, Jo DG, Lathia JD, Siler DA, Chigurupati S, Ouyang X, Magnus T, Camandola S, Mattson MP (2007) Pivotal role for neuronal toll-like receptors in ischemic brain injury and functional deficits. Proc Natl Acad Sci U S A 104:13798–13803. CrossRefPubMedPubMedCentralGoogle Scholar
  42. Thomas B, Beal MF (2007) Parkinson’s disease. Hum Mol Genet 16:R183–R194. CrossRefPubMedGoogle Scholar
  43. Trotta T, Porro P, Calvello R, Panaro MA (2014) Biological role of toll-like receptor-4 in the brain. J Neuroimmunol 268:1–12. CrossRefPubMedGoogle Scholar
  44. Venezia S, Refolo V, Polissidis A, Stefanis L, Wenning GK, Stefanova N (2017) Toll-like receptor 4 stimulation with monophosphoryl lipid A ameliorates motor deficits and nigral neurodegeneration triggered by extraneuronal α-synucleinopathy. Mol Neurodegener 12:52.
  45. Wu DC, Jackson-Lewis V, Vila M, Tieu K, Teismann P, Vadseth C, Choi DK, Ischiropoulos H, Przedborski S (2002) Blockade of microglial activation is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson disease. J Neurosci 22:1763–1771CrossRefPubMedGoogle Scholar
  46. Zhang W, Wang T, Pei Z, Miller DS, Wu X, Block ML, Wilson B, Zhang W, Zhou Y, Hong JS, Zhang J (2005) Aggregated alpha-synuclein activates microglia: a process leading to disease progression in Parkinson’s disease. FASEB J 19:533–542. CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Pharmaceutical SciencesUniversity of PerugiaPerugiaItaly
  2. 2.Department of Experimental MedicineUniversity of PerugiaPerugiaItaly

Personalised recommendations