(1) Background: Arboviruses of medical and veterinary significance have been identified on all seven continents, with every human and animal population at risk for exposure. Like arboviruses, chronic neurodegenerative diseases, like Alzheimer’s and Parkinson’s disease, are found wherever there are humans. Significant differences in baseline gene and protein expression have been determined between human-induced pluripotent stem cell lines derived from non-Parkinson’s disease individuals and from individuals with Parkinson’s disease. It was hypothesized that these inherent differences could impact cerebral organoid responses to viral infection. (2) Methods: In this study, cerebral organoids from a non-Parkinson’s and Parkinson’s patient were infected with Chikungunya virus and observed for two weeks. (3) Results: Parkinson’s organoids lost mass and exhibited a differential antiviral response different from non-Parkinson’s organoids. Neurotransmission data from both infected non-Parkinson’s and Parkinson’s organoids had dysregulation of IL-1, IL-10, and IL-6. These cytokines are associated with mood and could be contributing to persistent depression seen in patients following CHIKV infection. Both organoid types had increased expression of CXCL10, which is linked to demyelination. (4) Conclusions: The differential antiviral response of Parkinson’s organoids compared with non-Parkinson’s organoids highlights the need for more research in neurotropic infections in a neurologically compromised host.

Arboviruses of medical and veterinary significance have been identified on all 7 continents with every human and animal population at risk for exposure. Like arboviruses, chronic neurodegenerative diseases like Alzheimer’s and Parkinson’s disease are found wherever there are humans. Viral parkinsonism has been documented for a variety of human pathogens though there are few studies that evaluate the effects of viral infection on degenerative neurological diseases. Significant differences in baseline gene and protein expression have been determined between Human Induced Pluripotent Stem Cell lines derived from a non-Parkinson’s disease individual and from an individual with reported Parkinson’s disease. While the organoids generated from each cell line were physically indistinguishable, significant differences were observed in gene and protein expression for neurotransmission and immunity. It was hypothesized that these inherent differences would impact cerebral organoid responses to viral infection. In this preliminary observational study, cerebral organoids from a non-Parkinson’s and Parkinson’s patient were infected with Chikungunya virus and observed for 2 weeks. Parkinson’s organoids lost mass and exhibited a dysfunctional antiviral response. Neurotransmission data from both non-Parkinson’s and Parkinson’s organoids had dysregulation of IL-1, IL-10, IL-6. These cytokines are associated with mood and could be contributing to persistent depression seen in patients following CHIKV infection. Both organoid types had increased expression of CCR5 and CXCL10 which are linked to demyelination, highlighting a potential mechanism for virus-associated parkinsonism. The dysfunctional antiviral response of Parkinson’s organoids highlights the need for more research in neurotropic infections in a neurologically compromised host.

The development of 3D cerebral brain organoids which accurately resemble aspects of the human brain permits a more accurate characterization of physiological processes and neurological diseases. Cerebral organoids can be grown from stem cell lines with various genetic backgrounds allowing multiple neurodegenerative diseases to be modeled. While dysfunction in neurotransmission of patients with neurodegenerative diseases is expected, the impact of chronic neurodegeneration on the response to viral infection of the CNS is poorly understood. For instance, several mosquito-borne viruses like Dengue virus and West Nile Virus cause post-viral parkinsonism. How CNS infection might impact a host with inherent CNS dysfunction such as Parkinson’s Disease in poorly understood. This preliminary, observational study aimed to understand dysfunction in intrinsic and innate expression of a patient with a neurodegenerative disease and a non-affected individual in relation to potential viral infection in the CNS. Cerebral organoids were generated from human induced pluripotent stem cells with a normal genetic background or with idiopathic Parkinson’s Disease. After differentiation and maturation, organoid size, gene expression and immunofluorescence were evaluated to assess neurotransmission and innate immunity. While there was no significant difference in size of the organoids with a normal or Parkinson’s genetic background, gene expression studies identified multiple differences in innate immunity and neurotransmission. Immunofluorescence also identified differences in protein expression related to neurotransmission and innate immunity. Of note, organoids derived from a Parkinson’s patient exhibited endogenous up-regulation of dopamine and muscarinic acetylcholine receptors, GABA, glycine, and glutamate targets, and the majority of cytokines. This expression pattern suggests a chronic state of neuroexcitation and neuroinflammation in this population of organoids.