Dose-dependent effects of intranasal lipopolysaccharide administration on alpha-synuclein levels in the olfactory epithelium and neuroinflammation in the olfactory bulbs of mice

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Abstract

BACKGROUND: Olfactory dysfunction is a prodromal symptom of many neurodegenerative diseases. Neuroinflammatory and neurodegenerative processes in the olfactory bulbs may be initiated by infectious agents in the nasal cavity, particularly bacterial lipopolysaccharide (LPS). The molecular mechanisms mediating the effects of this endotoxin on the olfactory epithelium and the development of pathological processes in the olfactory bulbs remain insufficiently studied.

AIM: This study aimed to investigate the effects of different doses of intranasally administered lipopolysaccharide on the intensity of immunopositive staining of the olfactory epithelium with antibodies against alpha-synuclein (α-syn) and the adaptor protein MyD88, as well as of olfactory bulbs with antibodies against α-syn and glial fibrillary acidic protein (GFAP).

METHODS: The study included 18 male BALB/c mice weighing 20–33 g. Animals received unilateral intranasal injections of sterile saline 10 μL daily (control) or lipopolysaccharide at a high (0.1 μg/mL) or low (0.01 μg/mL) concentration. After 28 days, the brains and nasal structure complexes were excised and frozen using dry ice. Serial cryostat sections (14 μm) were prepared and stained with methylene blue and antibodies against α-syn, MyD88, and GFAP. The intensity of immunolabeling was quantitatively assessed using Image-Pro Insight 8.0 software.

RESULTS: Unilateral intranasal administration of lipopolysaccharide solution to mice resulted in a dose-dependent increase in α-syn levels in receptor cells, olfactory nerve bundles, and olfactory bulb glomeruli, along with a dose-dependent increase in MyD88 in the receptor epithelium and GFAP in the glomerular layer of the olfactory bulb ipsilateral to endotoxin administration.

CONCLUSION: The observed morphological and immunohistochemical changes in the olfactory bulbs following intranasal lipopolysaccharide administration indicate the development of dose-dependent neuroinflammation in the glomerular layer. Neuroinflammation in the olfactory bulb appears to be initiated by LPS-induced upregulation of α-syn expression in receptor neurons projecting to the bulbs, mediated by activation of MyD88, which participates in intracellular signaling downstream of Toll-like receptors and interleukin-1 receptor family members.

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About the authors

Kseniya S. Sergeeva

Udmurt State University

Email: ksui1@yandex.ru
ORCID iD: 0000-0002-3358-9611
SPIN-code: 8561-7850
Russian Federation, Izhevsk

Tatyana N. Sergeeva

Udmurt State University

Email: tnbio@ya.ru
ORCID iD: 0000-0001-8273-8348
SPIN-code: 9300-2217
Russian Federation, Izhevsk

Ivan A. Cherenkov

Udmurt State University

Email: ivch@ya.ru
ORCID iD: 0000-0002-9565-4271
SPIN-code: 1669-0353

Cand. Sci. (Biology), Associate Professor

Russian Federation, Izhevsk

Valeriy G. Sergeyev

Udmurt State University; Izhevsk State Medical Academy

Author for correspondence.
Email: cellbio@ya.ru
ORCID iD: 0000-0002-5211-1832
SPIN-code: 1476-3236

Dr. Sci. (Biology), Associate Professor

Russian Federation, Izhevsk; Izhevsk

References

  1. Fatuzzo I, Niccolini GF, Zoccali F, et al. Neurons, nose, and neurodegenerative diseases: Olfactory function and cognitive impairment. Int J Mol Sci. 2023;24(3):2117. doi: 10.3390/ijms24032117 EDN: YQBCWE
  2. Torres-Pasillas G, Chi-Castañeda D, Carrillo-Castilla P, et al. Olfactory dysfunction in Parkinson’s disease, its functional and neuroanatomical correlates. NeuroSci. 2023;4(2):134–151. doi: 10.3390/neurosci4020013 EDN: NNFHDF
  3. Son G, Jahanshahi A, Yoo SJ, et al. Olfactory neuropathology in Alzheimer’s disease: a sign of ongoing neurodegeneration. BMB Rep. 2021;54(6):295–304. doi: 10.5483/BMBRep.2021.54.6.055 EDN: HNZFGT
  4. Abele M, Riet A, Hummel T, et al. Olfactory dysfunction in cerebellar ataxia and multiple system atrophy. J Neurol. 2003;250(12):1453–1455. doi: 10.1007/s00415-003-0248-4 EDN: EUMZWJ
  5. Huang X, Wu J, Zhang N, et al. Smell loss is associated with cognitive impairment in amyotrophic lateral sclerosis patients. CNS Neurosci Ther. 2024;30(7):e14851. doi: 10.1111/cns.14851 EDN: OBHYFB
  6. Patino J, Karagas NE, Chandra S, et al. Olfactory dysfunction in Huntington’s disease. J Huntingtons Dis. 2021;10(4):413–422. doi: 10.3233/JHD-210497 EDN: JRUYBH
  7. Franco R, Garrigós C, Lillo J. The olfactory trail of neurodegenerative diseases. Cells. 2024;13(7):615. doi: 10.3390/cells13070615 EDN: IUWZPW
  8. Chen F, Liu W, Liu P, et al. α-Synuclein aggregation in the olfactory bulb induces olfactory deficits by perturbing granule cells and granular-mitral synaptic transmission. NPJ Parkinsons Dis. 2021;7(1):114. doi: 10.1038/s41531-021-00259-7 EDN: OLQWSI
  9. Flores-Cuadrado A, Saiz-Sanchez D, Mohedano-Moriano A, et al. Astrogliosis and sexually dimorphic neurodegeneration and microgliosis in the olfactory bulb in Parkinson’s disease. NPJ Parkinsons Dis. 2021;7(1):11. doi: 10.1038/s41531-020-00154-7 EDN: CTPWMC
  10. Li KL, Huang HY, Ren H, Yang XL. Role of exosomes in the pathogenesis of inflammation in Parkinson’s disease. Neural Regen Res. 2022;17(9):1898–1906. doi: 10.4103/1673-5374.335143 EDN: VEPVNK
  11. Tonelli LH, Postolache TT. Airborne inflammatory factors: “from the nose to the brain”. Front Biosci (Schol Ed). 2010;2(1):135–152. doi: 10.2741/s52
  12. Niu H, Wang Q, Zhao W, et al. IL-1β/IL-1R1 signaling induced by intranasal lipopolysaccharide infusion regulates alpha-Synuclein pathology in the olfactory bulb, substantia nigra and striatum. Brain Pathol. 2020;30(6):1102–1118. doi: 10.1111/bpa.12886 EDN: STHSNG
  13. Tomlinson JJ, Shutinoski B, Dong L, et al. Holocranohistochemistry enables the visualization of α-synuclein expression in the murine olfactory system and discovery of its systemic anti-microbial effects. J Neural Transm (Vienna). 2017;124(6):721–738. doi: 10.1007/s00702-017-1726-7 EDN: KXQYWC
  14. Ciesielska A, Matyjek M, Kwiatkowska K. TLR4 and CD14 trafficking and its influence on LPS-induced pro-inflammatory signaling. Cell Mol Life Sci. 2021;78(4):1233–1261. doi: 10.1007/s00018-020-03656-y EDN: TLETKQ
  15. Liu M, Kang W, Hu Z, et al. Targeting MyD88: Therapeutic mechanisms and potential applications of the specific inhibitor ST2825. Inflamm Res. 2023;72(10-11):2023–2036. doi: 10.1007/s00011-023-01801-4 EDN: VYNSPP
  16. Corps KN, Islam Z, Pestka JJ, Harkema JR. Neurotoxic, inflammatory, and mucosecretory responses in the nasal airways of mice repeatedly exposed to the macrocyclic trichothecene mycotoxin roridin A: dose-response and persistence of injury. Toxicol Pathol. 2010;38(3):429–451. doi: 10.1177/0192623310364026 EDN: NYVRRR
  17. Guo L, Cheng J, Lian S, et al. Structural basis of amine odorant perception by a mammal olfactory receptor. Nature. 2023;618(7963):193–200. doi: 10.1038/s41586-023-06106-4 EDN: SGXXSK
  18. Kim Y, McInnes J, Kim J, et al. Olfactory deficit and gastrointestinal dysfunction precede motor abnormalities in alpha-Synuclein G51D knock-in mice. Proc Natl Acad Sci U S A. 2024;121(39):e2406479121. doi: 10.1073/pnas.2406479121 EDN: KMGBDT
  19. Hasegawa-Ishii S, Shimada A, Imamura F. Lipopolysaccharide-initiated persistent rhinitis causes gliosis and synaptic loss in the olfactory bulb. Sci Rep. 2017;7(1):11605. doi: 10.1038/s41598-017-10229-w
  20. Asano H, Hasegawa-Ishii S, Arae K, et al. Infiltration of peripheral immune cells into the olfactory bulb in a mouse model of acute nasal inflammation. J Neuroimmunol. 2022;368:577897. doi: 10.1016/j.jneuroim.2022.577897 EDN: UHXEKT
  21. Ubina T, Agnew-Svoboda W, Figueroa ZA, et al. Protocol for the longitudinal study of neuroinflammation and reactive astrocytes in Lcn2CreERT2 mice. STAR Protoc. 2024;5(4):103322. doi: 10.1016/j.xpro.2024.103322 EDN: HNFHLE
  22. Zhao Y, Huang Y, Cao Y, Yang J. Astrocyte-mediated neuroinflammation in neurological conditions. Biomolecules. 2024;14(10):1204. doi: 10.3390/biom14101204 EDN: GKELWT
  23. Wyss-Coray T, Mucke L. Inflammation in neurodegenerative disease—a double-edged sword. Neuron. 2002;35(3):419–432. doi: 10.1016/s0896-6273(02)00794-8 EDN: MAHIWZ
  24. Guo S, Wang H, Yin Y. Microglia polarization from M1 to M2 in neurodegenerative diseases. Front Aging Neurosci. 2022;14:815347. doi: 10.3389/fnagi.2022.815347 EDN: YCJYRW
  25. Fan YY, Huo J. A1/A2 astrocytes in central nervous system injuries and diseases: Angels or devils? Neurochem Int. 2021;148:105080. doi: 10.1016/j.neuint.2021.105080 EDN: LGOVMR
  26. Beatman EL, Massey A, Shives KD, et al. Alpha-synuclein expression restricts RNA viral infections in the brain. J Virol. 2015;90(6):2767–2782. doi: 10.1128/JVI.02949-15
  27. He Q, Yu W, Wu J, et al. Intranasal LPS-mediated Parkinson’s model challenges the pathogenesis of nasal cavity and environmental toxins. PLoS One. 2013;8(11):e78418. doi: 10.1371/journal.pone.0078418
  28. Loria F, Vargas JY, Bousset L, et al. α-Synuclein transfer between neurons and astrocytes indicates that astrocytes play a role in degradation rather than in spreading. Acta Neuropathol. 2017;134(5):789–808. doi: 10.1007/s00401-017-1746-2 EDN: VTLTSM
  29. Lee HJ, Suk JE, Patrick C, et al. Direct transfer of alpha-synuclein from neuron to astroglia causes inflammatory responses in synucleinopathies. J Biol Chem. 2010;285(12):9262–9272. doi: 10.1074/jbc.M109.081125
  30. Isik S, Yeman Kiyak B, Akbayir R, et al. Microglia mediated neuroinflammation in Parkinson’s disease. Cells. 2023;12(7):1012. doi: 10.3390/cells12071012 EDN: BBWEAD
  31. Ma K, Guo J, Wang G, et al. Toll-like receptor 2-mediated autophagy promotes microglial cell death by modulating the microglial M1/M2 phenotype. Inflammation. 2020;43(2):701–711. doi: 10.1007/s10753-019-01152-5 EDN: BLKOHA
  32. Choi I, Zhang Y, Seegobin SP, et al. Microglia clear neuron-released α-synuclein via selective autophagy and prevent neurodegeneration. Nat Commun. 2020;11(1):1386. doi: 10.1038/s41467-020-15119-w EDN: GGBNEU
  33. Jha MK, Jo M, Kim JH, Suk K. Microglia-astrocyte crosstalk: an intimate molecular conversation. Neuroscientist. 2019;25(3):227–240. doi: 10.1177/1073858418783959
  34. Dutta D, Jana M, Majumder M, et al. Selective targeting of the TLR2/MyD88/NF-κB pathway reduces α-synuclein spreading in vitro and in vivo. Nat Commun. 2021;12(1):5382. doi: 10.1038/s41467-021-25767-1 EDN: GMFFJT
  35. Dong Z, Yang Z, Wang C. Expression of TLR2 and TLR4 messenger RNA in the epithelial cells of the nasal airway. Am J Rhinol. 2005:19(3):236–239.
  36. MacRedmond RE, Greene CM, Dorscheid DR, et al. Epithelial expression of TLR4 is modulated in COPD and by steroids, salmeterol and cigarette smoke. Respir Res. 2007;8(1):84. doi: 10.1186/1465-9921-8-84

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2. Fig. 1. Intranasal administration of lipopolysaccharide induces a dose-dependent increase in immunopositive α-syn (alpha-synuclein) and MyD88 levels in the olfactory epithelium: a, immunopositive staining for α-syn and MyD88 in olfactory epithelial cells following intranasal administration of sterile buffered saline (Контр), low-dose lipopolysaccharide (ЛПСм), and high-dose lipopolysaccharide (ЛПСб). Arrows indicate the region of dendritic knob localization in receptor neurons; asterisks indicate olfactory nerve fiber bundles. Rectangles mark regions of interest selected for quantification of immunostaining intensity; magnification ×40; scale bar: α-syn, 20 μm; MyD88, 45 μm; b, intensity of immunopositive labeling for MyD88 and α-syn measured in standardized areas in control and experimental groups, expressed as a percentage relative to control animals, with values taken as 100%. Data are presented as mean ± standard deviation. Significance was determined using one-way analysis of variance (ANOVA); * p < 0.05; ** p < 0.01; *** p < 0.001 (n = 6 per group).

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3. Fig. 2. Asymmetric enhancement of α-syn (alpha-synuclein) immunopositive staining in olfactory nerve fibers (indicated by arrows) in the half of the nasal septum (НП) facing the nasal cavity into which lipopolysaccharide was administered (marked with an asterisk). ПХ, septal cartilage. Magnification ×40. Scale bar = 65 μm.

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4. Fig. 3. Intranasal administration of lipopolysaccharide induces a dose-dependent increase in cytosis and immunopositive α-syn (alpha-synuclein) and GFAP (glial fibrillary acidic protein) expression in the glomerular layer of the olfactory bulb: a, cells of the glomerular layer of the olfactory bulb stained with methylene blue (МС) and immunopositive labeling for α-syn (α-син) and GFAP (GFAP) in cells and processes within the glomerular layer of the olfactory bulb on the side of intranasal administration of saline (Контр), low-dose lipopolysaccharide (ЛПСм), and high-dose lipopolysaccharide (ЛПСб); selected glomeruli are indicated by arrows; magnification ×40; scale bar = 60 μm; b, number of MB-stained cells and intensity of immunopositive α-syn and GFAP labeling measured in identical regions of control and experimental animals, expressed as a percentage relative to control animals, with values taken as 100%. Data are presented as mean ± standard deviation. Significance was determined using one-way analysis of variance (ANOVA); * p < 0.05; ** p < 0.01; *** p < 0.001 (n = 6 per group).

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