Methodologies for Generating Brain Organoids to Model Viral Pathogenesis in the CNS

Abstract

(1) Background: The human brain is of interest in viral research because it is often the target of viruses. Neurological infections can result in consequences in the CNS, which can result in death or lifelong sequelae. Organoids modeling the CNS are notable because they are derived from stem cells that differentiate into specific brain cells such as neural progenitors, neurons, astrocytes, and glial cells. Numerous protocols have been developed for the generation of CNS organoids, and our goal was to describe the various CNS organoid models available for viral pathogenesis research to serve as a guide to determine which protocol might be appropriate based on research goal, timeframe, and budget. (2) Methods: Articles for this review were found in Pubmed, Scopus and EMBASE. The search terms used were “brain + organoid” and “CNS + organoid” (3) Results: There are two main methods for organoid generation, and the length of time for organoid generation varied from 28 days to over 2 months. The costs for generating a population of organoids ranged from USD 1000 to 5000. (4) Conclusions: There are numerous methods for generating organoids representing multiple regions of the brain, with several types of modifications for fine-tuning the model to a researcher’s specifications. Organoid models of the CNS can serve as a platform for characterization and mechanistic studies that can reduce or eliminate the use of animals, especially for viruses that only cause disease in the human CNS.

Human Brain Organoids as Models for Central Nervous System Viral Infection

“…Additionally, the diversity in protocols, for both unguided whole brain and guided brain-region specific organoid generation, could be another cause of heterogenic results. However, both whole brain and region-specific organoid models have a role in generating and testing hypotheses, with region-specific organoid models being best applied to testing-specific hypotheses [ 18 ]. For instance, in whole brain organoids, SARS-CoV-2 was found to mainly infect ChP cell clusters, leading to the hypothesis that SARS-CoV-2 disrupts the ChP barrier, which was tested by subsequent studies in ChP organoids.…”

“…A large variety of available protocols describe either the generation of an organoid that models the whole brain through non-guided differentiation, known as cerebral organoids, or the formation of specific regions of the human brain, such as the forebrain, hindbrain, telencephalon, and choroid plexus (ChP) organoids [ 16 , 17 ]. Both methods of organoid generation have been deployed in the field of virology [ 18 ]. Brain organoid models are a suitable reflection of the human brain, as their development parallels the development of the human brain, with different cell types arising over the course of organoid maturation [ 17 ].…”

“…Recently, other reviews have been published discussing the potential and methodology of brain organoids for virology research [ 12 , 18 , 31 , 32 , 33 , 34 ]. These reviews focus on the application of brain organoids and other human stem cell models for a specific virus, multiple viruses [ 12 , 31 , 32 , 33 , 34 ], or on the types of brain organoid generation protocols used for virology [ 18 ]. In this review, we include all research on viral CNS infections using iPSC and ESC human brain organoids.…”

Vascularized human brain organoid on-chip

“…The cost for generating a batch of organoids is currently estimated to be around USD 1000 to 5000. 228 This is mainly due to the long culturing period that might take years, as well as the use of expensive materials such as Matrigel and the medium. Thus, there have been ongoing efforts attempting to find better alternatives to reduce the time and cost for producing brain organoids.…”

Host–Pathogen Interactions: Organotypic Cultures to Unravel the Mysteries of the Primordial Hostility among Organisms

“…In their review, Marrazzo et al [ 28 ] discussed the use of brain organoids as valuable models for ZIKV infection, underlining the advantages of these models in accelerating research. As described by Hopkins et al [ 29 ], brain organoids represent invaluable models in studying several pathogenic disorders that affect the brain and the nervous system. In their review, they thoroughly discussed the effectiveness and advantages of the use of these models and recognized the existing cost and technology limitations.…”