Caracterització dels heteròmers cb1-5-ht2a al neuroepiteli olfactiu de consumidors de cànnabis i pacients amb esquizofrènia: implicacions clíniques i cognitives

• Autores: Daniel Guinart Mulero
• Directores de la Tesis: Liliana Galindo Guarin (dir. tes.), V. Pérez Solá (codir. tes.), Patricia Robledo Montoya (codir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2021
• Idioma: catalán
• Tribunal Calificador de la Tesis: Benedicto Crespo Facorro (presid.), Daniel Bergè Baquero (secret.), Sergi Ferre (voc.)
• Programa de doctorado: Programa de Doctorado en Psiquiatría por la Universidad Autónoma de Barcelona
• Materias:
  • Ciencia política
    • Opinión publica
      • Información
• Enlaces
  • Tesis en acceso abierto en: TDX
• Resumen

  • A clear link between etiology, pathophysiology and biological processes in schizophrenia, and its relation to specific behavioral or cognitive symptoms, remains largely to be traced. However, both the serotoninergic and the cannabinoid system have been related to the pathophysiology of schizophrenia, and studies in mice show that CB1R and 5-HT2AR form heteromers that are expressed and functionally active in the brain, where they specifically mediate the memory impairment induced by cannabis. An additional challenge in neuropsychiatric research derives from the lack of access to viable in vivo neurological tissue. However, recently, due to its accessibility and cellular composition, the olfactory neuroepithelium (ON) has emerged as a promising tool to explore the cellular and molecular processes underlying neuropsychiatric disorders. Thus, in this thesis we aimed to study the cellular, molecular, and electrophysiological properties of olfactory neuroepithelial cells in healthy control subjects and cannabis users, determine the expression and functionality of CB1-5-HT2A heteromers in olfactory neuroepithelium cells of healthy controls and cannabis users, evaluate the formation and functionality of CB1-5-HT2A heteromers in the olfactory neuroepithelium of schizophrenic patients (cannabis users and non-cannabis users), as compared to healthy controls (cannabis users and non-cannabis users), correlate the expression of CB1-5-HT2A heteromers with features related to the use of cannabis, cognitive performance, neurological soft signs, and clinical variables, and explore the in vitro effects of antipsychotic treatment in olfactory neuroepithelium cells from healthy controls and chronic cannabis users on the functionality of CB1-5-HT2A heteromers. After successful non-invasive exfoliation, we found that ON cells of healthy control subjects and cannabis users express proteins associated with neuronal markers and genes related to neuronal precursors. We also found that the ON of healthy control subjects and cannabis users show similar cell differentiation and sodium channel functionality, and that functional CB1R-5-HT2AR heteromers are expressed in the ON of healthy controls, cannabis users and schizophrenia patients, and that CB1R-5-HT2AR heteromer formation is increased in cannabis users and schizophrenia patients, with and without a history of chronic cannabis use. Additionally, we report that a significant link exists between cannabis use and the formation of CB1R-5-HT2AR heteromers and a significant correlation occurs in the general population between the expression of CB1R-5-HT2AR heteromers and attention and NSS, all of which shows that the CB1R-5-HT2AR heteromer is a potentially relevant biomarker of neurocognitive alterations in a population consisting of healthy controls, cannabis users and schizophrenia patients (cannabis and non-cannabis users) and highlights the potential role of the ON as a tool to explore biomarkers of neuropsychiatric disorders. Interestingly, we found that the molecular signature of CB1R-5-HT2AR heteromers is altered in schizophrenia patients, and this effect is prevented by cannabis use and suggest that treatment with clozapine, but not aripiprazole, may induce alterations in the functionality of CB1R-5HT2AR heteromers through changes in the quaternary structure of the heteromer, and cannabis use prevents these changes. Taken together, our data put forward that the CB1R-5-HT2AR heteromer could be a molecular marker of the interaction between antipsychotic medication and cannabis use in schizophrenia with relevance for neurocognitive performance. Nonetheless, our design was cross-sectional, so it is unknown if results may change over time. Other neuropsychiatric control groups would have been needed to elucidate the diagnostic specificity of our findings. Lastly, future studies will need to include subjects free of antipsychotic treatment.