Rosa Villanueva- Departamento de Psiquiatría y Salud Mental, Hospital Universitario La Paz, La Paz, Madrid, Spain
Tridimensional cultures of human induced pluripotent cells (iPSCs) experimentally directed to neural differentiation, termed “brain organoids” are now employed as an in vitro assay that recapitulates early developmental stages of nervous tissue differentiation. Technical progress in culture methodology enabled the generation of regionally specialized organoids with structural and neurochemical characters of distinct encephalic regions. The technical process of organoid elaboration is undergoing progressively implementation, but current robustness of the assay has attracted the attention of psychiatric research to substitute/complement animal experimentation for analyzing the pathophysiology of psychiatric disorders. Numerous morphological, structural, molecular and functional insights of psychiatric disorders have been uncovered by comparing brain organoids made with iPSCs obtained from control healthy subjects and psychiatric patients. Brain organoids were also employed for analyzing the response to conventional treatments, to search for new drugs, and to anticipate the therapeutic response of individual patients in a personalized manner. In this review, we gather data obtained by studying cerebral organoids made from iPSCs of patients of the three most frequent serious psychiatric disorders: schizophrenia, major depression disorder, and bipolar disorder. Among the data obtained in these studies, we emphasize: (i) that the origin of these pathologies takes place in the stages of embryonic development; (ii) the existence of shared molecular pathogenic aspects among patients of the three distinct disorders; (iii) the occurrence of molecular differences between patients bearing the same disorder, and (iv) that functional alterations can be activated or aggravated by environmental signals in patients bearing genetic risk for these disorders.
Introduction
Preclinical psychiatric research has attempted for decades to generate animal models that replicate mental disorders (1-3). The advances obtained in the study of the human genome, and the alterations detected in patients with different neuropsychiatric pathologies have contributed to consolidating the generation of genetically modified animal models to uncover pathogenic mechanisms of behavioral alterations. However, the structural complexity of the nervous system and human behavior compared to other mammals (4–8) together with the polygenic nature of the genome alterations detected in psychiatric disorders (9), limited the progress of psychiatry based on preclinical studies using animal models. It must be taken into account that rodents, used more frequently in biomedical research, from an evolutionary point of view are more than 90 million years older in their origin compared to humans and have enormous structural and functional differences (10).
From initial studies in the middle of the last century, modeling neural tissue differentiation by in vitro assays, constituted a promising tool to overcome limitations of animal models for the study neuropsychiatric disorders. The conventional 2D in vitro approaches enabled the study of morphological, molecular, and electrophysiological features of neurons and glia, providing remarkable insights in the mechanisms that regulate normal and abnormal neural tissue differentiation, as well as, for the identification of alterations induced in response to drug administration [(see 11–14)].
In addition, the use of mixed cultures containing combinations of wild-type or abnormal, (i.e., genetically modified), neural cells were of great help to explore basic neuropathological mechanisms. Data obtainable from conventional two-dimensional cultures include aspects such as of neurite outgrowth, synaptogenesis, the release of neurotransmisors, being also useful to design protocols that direct differentiation of stem cell towards neuron and glia subtypes (15, 16). A major weakness of two-dimensional cultures (2D-cultures) came from their impossibility to replicate the complex architecture of neurons and glia in distinct brain regions that is of critical importance for function (17).
Attempts to develop three-dimensional cultures to study the structure and function of specific neural circuits, employed substrate scaffolds that support the formation of neural networks (18). In the last decade, advances in tissue bioengineering generated efficient 3D multicellular culture systems, termed “organoids” where cells growing in matrix substrates are able to self-organizing and re-capitulate, quite accurately, functional and structural development of the adult organs [reviewed by Goldrick et al. (19)]. Many methodology variations to the basic organoid technology has been introduce in the last years to adapt the assay to unravel specific questions (20). Among these variations are the formation of 3D cultures free of matrix scaffold, termed “spheroids,” or the combination of organoids obtained from distinct cell sources to explore interactions involving distinct cell types, that has been termed “assembloids” (21, 22). Overall, organoids provided a great methodological advance to study the bases of multiple human pathologies including neuropsychiatric disorders and, most important, to test the effects of different treatments in a personalized fashion [(see 11, 12, 14)]. The progress achieved in the organoid technology in the last years has open the possibility to employ brain organoids in the next future, as biological chips for artificial intelligence (23, 24). The term of “organoid intelligence” has been proposed for this potential application (24).
First approaches in the design of three-dimensional cell cultures have been carried out using stem cells obtained largely from experimental animals. However, in the first decade of this century, the contribution of the Japanese Nobel awarded Shinya Yamanaka and other research groups in cell reprogramming has led to a revolution in the application of organoids to the study of human pathology. Takahashi and Yamanaka (25) managed to generate pluripotent stem cells by transfecting fibroblasts obtained from the skin of adult subjects with a cocktail of 4 genes, which encode for transcription factors. These cells were called “induced pluripotent stem cells” (iPSCs) and grown under appropriate conditions are capable of differentiating into all cell lines, including specific neuron subtypes and glia (26). The procedures to obtain IPSCs have been implemented in subsequent studies, allowing the use of different cells from adult tissues as a source to obtain iPSCs (27).
Since the studies by Lancaster et al. (28), it has been found that brain organoids replicate the establishment of interneuronal connections and the production of neurotransmitters. In addition, it has been verified that according to culture protocols (29) brain organoids can be designed to replicate the structural and neurochemical characteristics of specific regions of the CNS [(see 7, 30, 31)], including diencephalon (32), brain stem (33), cerebellum (34), spinal cord (35, 36) and even to develop models of the cerebral cortex (37, 38). Furthermore, the combination of optogenetic techniques transfecting neural progenitors with genes that encode markers that are stimulated by light, allows highly sophisticated functional studies to be carried out (39).
Despite the extraordinary utility of organoids for the study of human brain development and pathology (40), they show weakness that need to be taken into account for appropriate modeling human diseases. From the technical point of view, a major shortcoming of current organoid methods is the lack of blood vessels in the culture. Due to insufficient surface diffusion, the interior of the organoid is under hypoxia resulting in central cell death. This causes slow tissue growth and developmental variability among distinct samples. Numerous efforts have been done to design procedures that ameliorate tissue nutrition. A relatively simple protocol is to slice organoids in thinner samples to bypass the diffusion limit and prevent cell death over long-term cultures. This method sustains development and neurogenesis in the organoid allowing the study of late stage cortical development (37).
A most promising modification of the tridimensional culture assays of special interest for drug screening, is the so-called “organ-on-a-chip” (41). In this assay, cells are cultured in micro-channels subjected to controlled fluid flow within a microfluidic device that is provided with biosensors to monitor biomarkers secreted by the organoids (42, 43). In addition to detect modifications induced by selected drug treatments, this assay enables to explore interactions between distinct organoids growing within channels interconnected together (“multiorgans microdevice”) or to generate a network of microvessels by adding growing vascular progenitors in connection with the organoid (44). Over-all, the organ-on-chip technology is a fast-moving field of research, and we could anticipate, that distinct types of these organ chip models will be manufactured and standardized in the next future [(see 42, 45)].
In clinical medicine, the use of non-neural organoids offers the possibility of being used as a personalized test for therapeutic planning of tumor pathology and degenerative diseases, and the application of neural tissue organoids to the study of psychiatric disorders is promising. Since iPSCs are obtained from patients, the differentiated components in the organoid share their alterations, including genetic abnormalities. In addition, the response to drug administration could replicate, at least in part, that caused if it were administered to the patient.
There are however major limitations of organoid technology when applied to gain clinical insights of psychiatric disorders. The first one is the inability of organoids for modeling cognitive and behavioral symptoms that are core features of psychiatric disorders. In some way, this is the same that happens in animal models. Another major limitation refers to the importance of environmental biopsychosocial factors such as life experiences or substance abuse in the evolution of psychiatric disorders. While some environmental factors such as drug abuse could be tested in the organoid assay, most of them are out of the organoid resolution. A further limitation of organoid studies came from the implication of different brain regions in the pathophysiology of psychiatric diseases. However, different strategies have been proposed to solve, at least in part, these limitations. As mentioned above, “assembloids” and/or organ-on-chip models (46) has been developed for this purpose. In addition, it is now possible investigating the functional effect of organoid implantation in the brain of host experimental animals. This is a novel aspect in the experimental use of brain organoids, which combines the formation of human organoids with animal experimentation. Models of implantation of mature organoids in the brain of adult or newborn experimental animals are being developed (47). Organoids have been shown to integrate into the cerebral cortex of host animals and have a specific influence on functional aspects of the selected brain area (48, 49). At present, there is only tentative data on the possible relevance of this experimental approach. However, it should be mentioned that within the field of neurology, neurological deficits due to traumatic cortical lesions in mice have been alleviated by implanting human organoids in the injured area (50). These results have raised ethical concerns due to the risk that chimeric animals may experience a certain degree of humanization that generates an increased perception of suffering (51, 52).
In summary, the use of brain organoids from psychiatric patients allows at least the following data to be obtained:
1. Detecting functional and structural alterations of nervous organs complementary to those obtained by imaging studies and in autopsy samples.
2. Exploring the effect of new drugs on the alterations present in organoids.
3. Verifying, in a personalized fashion, the effect and efficacy of the different possible treatments for the patient’s disorder (53).
4. Investigating the functional effect of their implantation in the brain of host experimental animals.
In this essay, we gather data obtained through the use of brain organoids regarding three highly prevalent pathologies in psychiatric clinic, including schizophrenia, major depression disorder, and bipolar disorder.
Schizophrenia
The elaboration of brain organoids through the use of iPSCs from schizophrenic patients has confirmed that it is a mental disorder associated with the development of the CNS, as well as confirming the alterations detected in postmortem studies and improving our knowledge about them (54). The most notable alterations of these organoids deal with neuronal development that included impaired differentiation of dopaminergic cells and lack of maturation of glutamatergic cells (55). From the cellular point of view, neurons with less dendritic branching and reduced synaptic connectivity are formed, and migration of neuroblasts within the tissue is deficient (56, 57). Functionally, electrophysiological alterations have been described due to abnormalities of Na+ channels, increased GABA-ergic neurotransmission (58) that generate imbalance between activating and inhibitory signaling (59, 60), and mitochondrial alterations accompanied by increased oxidative stress (61, 62). The later has been proposed to be a central feature of SCZD since transfer of normal mitochondria to SCZD-iPSCs cells improved differentiation of glutamatergic neurons and, in vivo similar treatment rescued attentional deficits in a rodent model of schizophrenia (63).
Consistent with the morphological and functional alterations, differences in the expression of a high number of genes and non-coding micro RNAs (mi-RNAs) with respect to controls have been also detected (56, 64). The panel of regulated genes includes components of the Wnt and cAMP signaling pathways (56), and regulation of the FGFR1 receptor (65, 66). Members of these signaling pathways play important roles in basic aspects of neural development and differentiation in the embryo. Other characteristic molecular alterations are the overexpression of the nuclear protein called disrupted in schizophrenia 1 (DIC 1); the reduction of the synaptic protein PSD95, that is a marker of excitatory synapses (67), and the mitotic arrest defient-1 gene (MAD1), that regulates neuronal migration (68). It is important to note that those proteins also regulate basic aspects of CNS development and neurotransmission.
Remarkably, not all the alterations have been observed in all the patients analyzed (67). Some of the alterations, such as MAD1 deficiency, or the increase expression of DISC 1, have been found also in other mental disorders such as major depression and bipolar disorder (69). We do not know if there is a common causal factor shared by these alterations, but it is known that major depression has a high incidence among schizophrenic patients (70).
Given that there are genetic variations between patients, the existence of different causal factors which converge in basic alterations of neural development, giving rise to a similar phenotype has been suggested (71). The heat shock-induced transcription factor, HSF1, has been identified as a protective factor in response to stress signals during embryonic development of the cerebral cortex whose regulation is deficient in iPSCs from schizophrenics (72). This fact would make the developing CNS of schizophrenics more vulnerable to different kinds of damaging agents (alcohol, hypoxia, convulsive pathology of the mother, etc.). In this same sense, it has been seen that organoids of schizophrenic patients are particularly vulnerable to exposure to the cytokine TNF alpha (tumor necrosis factor) generated by immune cells, suggesting that environmental factors, including maternal immune activation due to infections during pregnancy, can act as a trigger in fetuses with a genetic background of SCZD (73).
Concerning the evaluation of the therapeutic efficacy of drugs using brain organoids, it has been observed that treatments with the antipsychotic loxapine improves the connectivity of neurons by increasing the expression of glutamate receptors and reducing the deficiency in the expression of members of the WNT family (56).
Major depression disorder
Major depression disorder (MDD) is a highly prevalent disorder in western countries, but its molecular bases are not yet fully established (74). Genetic epidemiological studies support a genetic basis with multiple subtype variations for this disorder (75). Clinical and pharmacologic studies support disruption of serotonergic neurotransmission as a central factor causal of the disorder and selective serotonin reuptake inhibitors (SSRIs) are considered first choice treatment. Numerous efforts were paid to design culture conditions to generate serotoninergic neuron from human iPSCs to explore alterations in MDD patients (76). However, the high number of patients resistant to SSRIs treatment (77), directed brain organoid-based research to elucidate the bases of resistance in order to unravel the pathophysiology of the disorder and to identify effective treatments.
When iPSCs from treatment-resistant patients have been studied, intensification of the response to serotonergic stimuli was detected in forebrain neurons associated with hyperactivity of excitatory serotonergic receptors (5-HT2A and 5-HT7) that did not appear in organoids from subjects normal or from MDD patients responding to SSRIs (78). This functional difference in treatment-resistant patients is associated with structural changes in serotonergic neurons, including increased growth of neuronal cell extensions and negative regulation of protocadherin alpha 6 and 8 genes involved in cell adhesion (79). An important aspect is that experimental silencing of protocadherin genes in organoids from healthy subjects replicated the branching expansion of serotonergic neurons detected in the MDDs of patients resistant to SSRIs, and protocadherin-KO mice display apparently depressive behaviors (80). Overall, studies suggest an important role for protocadherins in resistance to SSRI treatments.
In recent years, the glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, Ketamine, has been used as a promising antidepressant with a very rapid (hours) and sustained response over time (more than 1 week) despite the fact that its half-life is very short (2 h). Using a brain organoid model, Cavalleri et al. (81) have observed that after the administration of ketamine there is an increase in the size of the soma and in the pattern of dendritic branching of dopaminergic neurons. These rapid-induced structural changes (6 h) are maintained for days, which could explain the sustainability of the treatment effects over time (82). On the other hand, the effect of ketamine was inhibited by adding rapamycin, which is a specific inhibitor of the receptor called mTOR involved in anabolic processes, and also by inhibitors of brain-derived neural growth factor, BDNF (81).
An alternative approach to the analysis of the mechanisms of action of antidepressants on MDD patients using brain organoids is the application of this technology to detect adverse effects on the embryo and fetuses of antidepressant drug treatments administered to pregnant women (83). Using this approach, Zohng et al. (84) have verified that treatments with 60 ng/mL of paroxetine decrease dendritic density and the population of oligodendrocytes in brain organoids of healthy subjects.
Bipolar disorder
Bipolar disorder (BD) is a chronic psychiatric condition characterized by severe swings in mood, alternating periods of major depression and manic or hypomanic periods. The familial distribution, as well as the incidence between twin brothers, has revealed the hereditary profile of this pathology.
The use of brain organoids and iPSCs in the study of this pathology has focused on two fundamental aspects of the alteration: the characterization of the molecular bases involved in the pathogenesis; and in the analysis of the effect and mechanism of action of the drugs used to stabilize mood [lithium, valproic acid, lamotrigine (85)].
Although the samples analyzed are limited, and the results are often heterogeneous, modern genetic studies using iPSCs from families or individuals with BP detected a very large number of genes regulated differently from healthy controls, which often appear also altered in other psychiatric disorders such as MDD or SCZD (86, 87).
The organoids derived from BD patients develop a smaller size, have fewer neurons, and form less excitable and less complex networks than the controls (85). In these organoids, genes that code for membrane receptors and ion channels appear over-expressed, and Ca++ signaling is significantly disturbed (88), in addition to regulating a very large number of genes involved in maturation and neuronal plasticity. Regulated genes include members of the Wnt signaling pathway and other genes that appear also modified in organoids or in postmortem samples derived from SCZD patients (87, 89).
Mood stabilizers, especially lithium, are the treatment of choice for BD to which most patients respond, and it has been considered that clarifying their mechanism of action could provide relevant information to characterize the pathogenesis of the disease. Consistent with this interpretation, lithium pretreatment of BD organoids has been observed to modify Ca++ fluxes, and the expression of genes that confer topographic identity to telencephalic neurons during development (88). In addition, prolonged lithium treatments are associated with transcriptional regulation of more than 100 genes, and functionally attenuate the loss of excitability in BD organoids while having opposite effects in organoids from healthy control subjects (85). One significant aspect is that the response of iPSCs to mood stabilizers correlates with the response to treatment of the BP patients from whom they are derived (85, 90).
Preliminary studies using rat cerebellar neurons exposed to mood stabilizers (lithium and valproic acid) and subjected to glutamate excitotoxicity have shown that mood stabilizers have a neuroprotective effect mediated by the regulation of microRNAs [miR-34a, miR-147b, miR-182, miR-222, miR-495, and miR-690 (91)]. Out of all these microRNAs, miR-34a is overexpressed in organoids derived from BD patients and its experimental overexpression in organoids from healthy subjects alters neuronal morphology, represses their differentiation and reduces the expression of synaptic proteins (92). In a complementary fashion, silencing miR-34a promotes the expansion of dendritic arborization. Based on these effects, it has been proposed that this micro-RNA could constitute a central element on which different BD-inducing agents act to trigger this psychiatric disorder (92). MicroRNAs are small units of RNA that do not directly code for protein formation but rather modify the synthesis of specific target proteins by repressing the translation of the corresponding messenger RNA. Several factors regulated by miR-34a have been identified that support the idea of a critical position of this micro-RNA in the molecular cascade involved in the pathogenesis of BP. One of these targets is the cellular cytoskeleton regulatory phosphoprotein, called “collapsin response mediator protein-2” (CRMP2) (93). CRMP2 is involved in the formation of dendritic spines.
The effects of brain organoid exposure to valproic acid are of particular clinical interest because its administration during pregnancy has been associated with a high incidence of autism spectrum syndrome in offsprings. In forebrain organoids, valproic acid, at high doses, has inhibitory effects on growth and neurogenesis, recapitulating the teratogenic effect of its administration during pregnancy (94).
Beside to the aforementioned alterations in neurons, BD organoids show alterations in astrocytes that cause less functional support for neurons and a reduction in their excitability. This effect is associated with a high production of interleukin-6 (IL-6) (95). IL6 proinflammatory signaling has no effect on iPSCs from healthy subjects, and does not appear to be a specific aspect of BD as it is also observed in iPSCs from schizophrenic patients (96). According to this last study, the action of IL6 is carried out on microglial cells and is consistent with the role of maternal inflammatory processes as a trigger for both psychiatric conditions (96).
Conclusions and prospects
Brain organoids emerge as a new methodological approach for the study of the nervous system that in combination with animal experimentation and large-scale genome-wide studies might provide in the next years a great advance in understanding the pathophysiology of psychiatric disorders providing also insights on new therapeutic approaches for those disorders.
From the numerous data obtained so far by employing iPSCs gathered in this essay we would emphasize four major conclusions: (i) that the origin of these pathologies takes place in the stages of embryonic development; (ii) the existence of shared molecular pathogenic aspects among patients of the three distinct disorders; (iii) the occurrence of molecular differences between patients bearing the same disorder; and, (iv) that functional alterations can be activated or aggravated by environmental signals in patients bearing genetic risk for these disorders.
In recent years, the abundance of shared symptomatology among psychiatric patients with distinct diagnosis together with the occurrence of considerable overlapping patterns of gene alterations in distinct mental disorders has led to a re-evaluation of the traditional categorical diagnostic classification of psychiatric nosology (DSM and ICD) for the advance of psychiatry (97). There is a growing consensus that a “transdiagnostic” approach focused in the analysis of common underlying mechanisms involved in multiple psychiatric disorders may be useful for a better understanding psychiatric disorders (98). Organoids can be used to investigate common mechanisms such as synaptic dysfunction, or neurogenesis deficits that may underlie multiple psychiatric conditions providing new criteria complementary to the information employed in transdiagnostic psychiatry (99). In this context, organoids can also serve as models for testing potential therapeutic interventions, which target these shared mechanisms rather than focusing on specific diagnostic.
Author contributions
The author confirms being the sole contributor of this work and has approved it for publication.
Conflict of interest
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Publisher’s note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
References
1. Callaway, E. Rat models on the rise in autism research. Nature. (2011). doi: 10.1038/nature.2011.9415
2. Forrest, AD, and Coto, CA, and, Siegel, SJ. (2014). Animal models of psychosis: current state and future directions. Curr Behav Neurosci Rep 1, 100–116, doi: 10.1007/s40473-014-0013-2
3. Białoń, M, and Wąsik, A. (2022). Advantages and Limitations of Animal Schizophrenia Models. Int J Mol Sci. 23: 5968. doi: 10.3390/ijms23115968
4. Howland, JG, Greenshaw, AJ, and Winship, IR. Practical aspects of animal models of psychiatric disorders. Can J Psychiatr. (2019) 64:3–4. doi: 10.1177/0706743718771833
5. Konopka, G, Friedrich, T, Davis-Turak, J, Winden, K, Oldham, MC, Gao, F, et al. Human-specific transcriptional networks in the brain. Neuron. (2012) 75:601–17. doi: 10.1016/j.neuron.2012.05.034
6. La Manno, G, Gyllborg, D, Codeluppi, S, Nishimura, K, Salto, C, Zeisel, A, et al. Molecular diversity of midbrain development in mouse, human, and stem cells. Cells. (2016) 167:566–580.e19. doi: 10.1016/j.cell.2016.09.027
7. Matsui, T.K., and Tsuru, Y., and, Kuwako, K.I. (2020). Challenges in modeling human neural circuit formation via brain organoid technology. Front Cell Neurosci 14::607399. doi: 10.3389/fncel.2020.607399
8. Tabata, H, Yoshinaga, S, and Nakajima, K. Cytoarchitecture of mouse and human subventricular zone in developing cerebral neocortex. Exp Brain Res. (2012) 216:161–8. doi: 10.1007/s00221-011-2933-3
9. Trubetskoy, V, Pardiñas, AF, Qi, T, Panagiotaropoulou, G, Awasthi, S, Bigdeli, TB, et al. Mapping genomic loci implicates genes and synaptic biology in schizophrenia. Nature. (2022) 604:502–8. doi: 10.1038/s41586-022-04434-5
10. Nei, M, Xu, P, and Glazko, G. Estimation of divergence times from multiprotein sequences for a few mammalian species and several distantly related organisms. Proc Natl Acad Sci U S A. (2001) 98:2497–502. doi: 10.1073/pnas.051611498
11. Alciati, A, Reggiani, A, Caldirola, D, and Perna, G. Human-induced pluripotent stem cell technology: toward the future of personalized psychiatry. J Pers Med. (2022) 12:1340. doi: 10.3390/jpm12081340
12. Dixon, TA, and Muotri, AR. Advancing preclinical models of psychiatric disorders with human brain organoid cultures. Mol Psychiatry. (2023) 28:83–95. doi: 10.1038/s41380-022-01708-2
13. Duval, K, Grover, H, Han, LH, Mou, Y, Pegoraro, AF, Fredberg, J, et al. Modeling physiological events in 2D vs. 3D cell culture. Physiology. (2017) 32:266–77. doi: 10.1152/physiol.00036.2016
14. Villanueva, R. Application of stem cells to the knowledge and treatment of psychiatric diseases. Actas Esp Psiquiatr. (2017) 45:303–6.
15. Cervetto, C, Pistollato, F, Amato, S, Mendoza-de Gyves, E, Bal-Price, A, Maura, G, et al. Assessment of neurotransmitter release in human iPSC-derived neuronal/glial cells: a missing in vitro assay for regulatory developmental neurotoxicity testing. Reprod Toxicol. (2023) 117:108358. doi: 10.1016/j.reprotox.2023.108358
16. Logan, S, Arzua, T, Canfield, SG, Seminary, ER, Sison, SL, Ebert, AD, et al. Studying human neurological disorders using induced pluripotent stem cells: from 2D monolayer to 3D organoid and blood brain barrier models. Compr Physiol. (2019) 9:565–611. doi: 10.1002/cphy.c180025
17. Nam, KH, Yi, SA, Jang, HJ, Han, JW, and Lee, J. In vitro modeling for inherited neurological diseases using induced pluripotent stem cells: from 2D to organoid. Arch Pharm Res. (2020) 43:877–89. doi: 10.1007/s12272-020-01260-z
18. Yan, M, Wang, L, Wu, Y, Wang, L, and Lu, Y. Three-dimensional highly porous hydrogel scaffold for neural circuit dissection and modulation. Acta Biomater. (2023) 157:252–62. doi: 10.1016/j.actbio.2022.12.011
19. Goldrick, C, Guri, I, Herrera-Oropeza, G, O’Brien-Gore, C, Roy, E, Wojtynska, M, et al. 3D multicellular systems in disease modelling: from organoids to organ-on-chip. Front Cell Dev Biol. (2023) 11:1083175. doi: 10.3389/fcell.2023.1083175
20. Saglam-Metiner, P, Devamoglu, U, Filiz, Y, Akbari, S, Beceren, G, Goker, B, et al. Spatio-temporal dynamics enhance cellular diversity, neuronal function and further maturation of human cerebral organoids. Commun Biol. (2023) 6:173. doi: 10.1038/s42003-023-04547-1
21. Birey, F, Andersen, J, Makinson, CD, Islam, S, Wei, W, Huber, N, et al. Assembly of functionally integrated human forebrain spheroids. Nature. (2017) 545:54–9. doi: 10.1038/nature22330
22. Schmidt, C. The rise of the assembloid. Nature. (2021) 597:S22–3. doi: 10.1038/d41586-021-02628-x
23. Magliaro, C, and Ahluwalia, A. To brain or not to brain. Front Sci. (2023) 1:1148873. doi: 10.3389/fsci.2023.1148873
24. Smirnova, L, Caffo, BS, Gracias, DH, Huang, Q, Pantoja, IEM, Tang, B, et al. Organoid intelligence (OI): the new frontier in biocomputing and intelligence-in-a-dish. FrontSci. (2023) 1:1017235. doi: 10.3389/fsci.2023.1017235
25. Takahashi, K, and Yamanaka, S. Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cells. (2006) 126:663–76. doi: 10.1016/j.cell.2006.07.024
26. Abdullah, A.I., and Pollock, A., and, Sun, T. (2012). The path from skin to brain: generation of functional neurons from fibroblasts. Mol Neurobiol, 45, 586–595, doi: 10.1007/s12035-012-8277-6
27. Park, B, Yoo, KH, and Kim, C. Hematopoietic stem cell expansion and generation: the ways to make a breakthrough. Blood Res. (2015) 50:194–203. doi: 10.5045/br.2015.50.4.194
28. Lancaster, MA, Renner, M, Martin, CA, Wenzel, D, Bicknell, LS, Hurles, ME, et al. Cerebral organoids model human brain development and microcephaly. Nature. (2013) 501:373–9. doi: 10.1038/nature12517
29. Mayhew, CN, and Singhania, R. A review of protocols for brain organoids and applications for disease modeling. STAR Protoc. (2022) 4:101860. doi: 10.1016/j.xpro.2022.101860
30. Parr, CJC, Yamanaka, S, and Saito, H. An update on stem cell biology and engineering for brain development. Mol Psychiatry. (2017) 22:808–19. doi: 10.1038/mp.2017.66
31. Zhang, Z, Wang, X, Park, S, Song, H, and Ming, GL. Development and application of brain region-specific organoids for investigating psychiatric disorders. Biol Psychiatry. (2023) 93:594–605. doi: 10.1016/j.biopsych.2022.12.015
32. Jo, J, Xiao, Y, Sun, AX, Cukuroglu, E, Tran, HD, Göke, J, et al. Midbrain-like organoids from human pluripotent stem cells contain functional dopaminergic and neuromelanin-producing neurons. Cell Stem Cell. (2016) 19:248–57. doi: 10.1016/j.stem.2016.07.005
33. Eura, N, Matsui, TK, Luginbühl, J, Matsubayashi, M, Nanaura, H, Shiota, T, et al. Brainstem organoids from human pluripotent stem cells. Front Neurosci. (2020) 14:538. doi: 10.3389/fnins.2020.00538
34. Muguruma, K, Nishiyama, A, Kawakami, H, Hashimoto, K, and Sasai, Y. Self-organization of polarized cerebellar tissue in 3D culture of human pluripotent stem cells. Cell Rep. (2015) 10:537–50. doi: 10.1016/j.celrep.2014.12.051
35. Ogura, T, Sakaguchi, H, Miyamoto, S, and Takahashi, J. Three-dimensional induction of dorsal, intermediate and ventral spinal cord tissues from human pluripotent stem cells. Development. (2018) 145:dev162214. doi: 10.1242/dev.162214
36. Xue, W, Li, B, Liu, H, Xiao, Y, Li, B, Ren, L, et al. Generation of dorsoventral human spinal cord organoids via functionalizing composite scaffold for drug testing. iScience. (2022) 26:105898. doi: 10.1016/j.isci.2022.105898
37. Qian, X, Su, Y, Adam, CD, Deutschmann, AU, Pather, SR, Goldberg, EM, et al. Sliced human cortical organoids for modeling distinct cortical layer formation. Cell Stem Cell. (2020) 26:766–781.e9. doi: 10.1016/j.stem.2020.02.002
38. Walsh, R., Giacomelli, E., Ciceri, G., Rittenhouse, C., Galimberti, M., Wu, Y., et al.et.al. (2023). Generation of human cerebral organoids with a structured outer subventricular zone. bioRxiv doi: 10.1101/2023.02.17.528906
39. Alich, TC, Röderer, P, Szalontai, B, Golcuk, K, Tariq, S, Peitz, M, et al. Bringing to light the physiological and pathological firing patterns of human induced pluripotent stem cell-derived neurons using optical recordings. Front Cell Neurosci. (2023) 16:1039957. doi: 10.3389/fncel.2022.1039957
40. Bose, S, Clevers, H, and Shen, X. Promises and challenges of organoid-guided precision medicine. Med. (2021) 2:1011–26. doi: 10.1016/j.medj.2021.08.005
41. Ingber, DE. Human organs-on-chips for disease modelling, drug development and personalized medicine. Nat Rev Genet. (2022) 23:467–91. doi: 10.1038/s41576-022-00466-9
42. Kim, J, Yoon, T, Kim, P, Bekhbat, M, Kang, SM, Rho, HS, et al. Manufactured tissue-to-tissue barrier chip for modeling the human blood-brain barrier and regulation of cellular trafficking. Lab Chip. (2023). doi: 10.1039/d3lc00124e
43. Zhang, YS, Aleman, J, Shin, SR, Kilic, T, Kim, D, Mousavi Shaegh, SA, et al. Multisensor-integrated organs-on-chips platform for automated and continual in situ monitoring of organoid behaviors. Proc Natl Acad Sci U S A. (2017) 114:E2293–302. doi: 10.1073/pnas.1612906114
44. Winkelman, MA, and Dai, G. Bioengineered perfused human brain microvascular networks enhance neural progenitor cell survival, neurogenesis, and maturation. Sci Adv. (2023) 9:eaaz9499. doi: 10.1126/sciadv.aaz9499
45. Monteduro, AG, Rizzato, S, Caragnano, G, Trapani, A, Giannelli, G, and Maruccio, G. Organs-on-chips technologies—a guide from disease models to opportunities for drug development. Biosens Bioelectron. (2023) 231:115271. doi: 10.1016/j.bios.2023.115271
46. Knight, E, and Przyborski, S. Advances in 3D cell culture technologies enabling tissue-like structures to be created in vitro. J Anat. (2015) 227:746–56. doi: 10.1111/joa.12257
47. Velasco, S. Modeling brain disorders using transplanted organoids: beyond the short circuit. Cell Stem Cell. (2022) 29:1617–8. doi: 10.1016/j.stem.2022.11.002
48. Jgamadze, D, Lim, JT, Zhang, Z, Harary, PM, Germi, J, Mensah-Brown, K, et al. Structural and functional integration of human forebrain organoids with the injured adult rat visual system. Cell Stem Cell. (2023) 30:137–152.e7. doi: 10.1016/j.stem.2023.01.004
49. Revah, O, Gore, F, Kelley, KW, Andersen, J, Sakai, N, Chen, X, et al. Maturation and circuit integration of transplanted human cortical organoids. Nature. (2022) 610:319–26. doi: 10.1038/s41586-022-05277-w
50. Bao, Z, Fang, K, Miao, Z, Li, C, Yang, C, Yu, Q, et al. Human cerebral organoid implantation alleviated the neurological deficits of traumatic brain injury in mice. Oxidative Med Cell Longev. (2021) 2021:6338722–16. doi: 10.1155/2021/6338722
51. Bassil, K, and Horstkötter, D. Ethical implications in making use of human cerebral organoids for investigating stress-related mechanisms and disorders. Camb Q Healthc Ethics. (2023) 17:1–13. doi: 10.1017/S0963180123000038
52. Chen, HI, Wolf, JA, Blue, R, Song, MM, Moreno, JD, Ming, GL, et al. Transplantation of human brain organoids: revisiting the science and ethics of brain chimeras. Cell Stem Cell. (2019) 25:462–72. doi: 10.1016/j.stem.2019.09.002
53. Avior, Y, Ron, S, Kroitorou, D, Albeldas, C, Lerner, V, Corneo, B, et al. Depression patient-derived cortical neurons reveal potential biomarkers for antidepressant response. Transl Psychiatry. (2021) 11:201. doi: 10.1038/s41398-021-01319-5
54. Nascimento, JM, Saia-Cereda, VM, Zuccoli, GS, Reis-de-Oliveira, G, Carregari, VC, Smith, BJ, et al. Proteomic signatures of schizophrenia-sourced iPSC-derived neural cells and brain organoids are similar to patients' postmortem brains. Cell Biosci. (2022) 12:189. doi: 10.1186/s13578-022-00928-x
55. Robicsek, O, Karry, R, Petit, I, Salman-Kesner, N, Müller, FJ, Klein, E, et al. Abnormal neuronal differentiation and mitochondrial dysfunction in hair follicle-derived induced pluripotent stem cells of schizophrenia patients. Mol Psychiatry. (2013) 18:1067–76. doi: 10.1038/mp.2013.67
56. Brennand, KJ, Simone, A, Jou, J, Gelboin-Burkhart, C, Tran, N, Sangar, S, et al. Modelling schizophrenia using human induced pluripotent stem cells. Nature. (2011) 473:221–5. doi: 10.1038/nature09915
57. Lee, J, Song, S, Lee, J, Kang, J, Choe, EK, Lee, TY, et al. Impaired migration of autologous induced neural stem cells from patients with schizophrenia and implications for genetic risk for psychosis. Schizophr Res. (2022) 246:225–34. doi: 10.1016/j.schres.2022.06.027
58. Page, SC, Sripathy, SR, Farinelli, F, Ye, Z, Wang, Y, Hiler, DJ, et al. Electrophysiological measures from human iPSC-derived neurons are associated with schizophrenia clinical status and predict individual cognitive performance. Proc Natl Acad Sci U S A. (2022) 119:e2109395119. doi: 10.1073/pnas.2109395119
59. Sawada, T, Chater, TE, Sasagawa, Y, Yoshimura, M, Fujimori-Tonou, N, Tanaka, K, et al. Developmental excitation-inhibition imbalance underlying psychoses revealed by single-cell analyses of discordant twins-derived cerebral organoids. Mol Psychiatry. (2020) 25:2695–711. doi: 10.1038/s41380-020-0844-z
60. Gao, R, and Penzes, P. Common mechanisms of excitatory and inhibitory imbalance in schizophrenia and autism spectrum disorders. Curr Mol Med. (2015) 15:146–67. doi: 10.2174/1566524015666150303003028
61. Ahmad, R., Sportelli, V., Ziller, M., and Spengler, D., and, Hoffmann, A. (2018). Tracing early neurodevelopment in schizophrenia with induced pluripotent stem cells. Cells, 7,:140, doi: 10.3390/cells7090140
62. Brennand, K, Savas, JN, Kim, Y, Tran, N, Simone, A, Hashimoto-Torii, K, et al. Phenotypic differences in HiPSC NPCs derived from patients with schizophrenia. Mol Psychiatry. (2015) 20:361–8. doi: 10.1038/mp.2014.22
63. Robicsek, O, Ene, HM, Karry, R, Ytzhaki, O, Asor, E, McPhie, D, et al. Isolated mitochondria transfer improves neuronal differentiation of schizophrenia-derived induced pluripotent stem cells and rescues deficits in a rat model of the disorder. Schizophr Bull. (2018) 44:432–42. doi: 10.1093/schbul/sbx077
64. Choudhary, A, Peles, D, Nayak, R, Mizrahi, L, and Stern, S. Current progress in understanding schizophrenia using genomics and pluripotent stem cells: a meta-analytical overview. Schizophr Res. (2022):S0920-9964(22)00406-6. doi: 10.1016/j.schres.2022.11.001
65. Narla, ST, Lee, YW, Benson, CA, Sarder, P, Brennand, KJ, Stachowiak, EK, et al. Common developmental genome deprogramming in schizophrenia—role of integrative nuclear FGFR1 signaling (INFS). Schizophr Res. (2017) 185:17–32. doi: 10.1016/j.schres.2016.12.012
66. Stachowiak, EK, Benson, CA, Narla, ST, Dimitri, A, Chuye, LEB, Dhiman, S, et al. Cerebral organoids reveal early cortical maldevelopment in schizophrenia—computational anatomy and genomics, role of FGFR1. Transl Psychiatry. (2017) 7:6. doi: 10.1038/s41398-017-0054-x
67. Brennand, KJ, Simone, A, Jou, J, Gelboin-Burkhart, C, Tran, N, Sangar, S, et al. Modelling Schizophrenia Using Human Induced Pluripotent Stem Cells. Nature. (2011) 473:221–225.
68. Goo, BS, Mun, DJ, Kim, S, Nhung, TTM, Lee, SB, Woo, Y, et al. Schizophrenia-associated mitotic arrest deficient-1 (MAD1) regulates the polarity of migrating neurons in the developing neocortex. Mol Psychiatry. (2023) 28:856–70. doi: 10.1038/s41380-022-01856-5
69. Nagel, M, Jansen, PR, Stringer, S, Watanabe, K, de Leeuw, CA, Bryois, J, et al. Meta-analysis of genome-wide association studies for neuroticism in 449, 484 individuals identifies novel genetic loci and pathways. Nat Genet. (2018) 50:920–7. doi: 10.1038/s41588-018-0151-7
70. Li, Z, Xue, M, Zhao, L, Zhou, Y, Wu, X, Xie, X, et al. Comorbid major depression in first-episode drug-naïve patients with schizophrenia: analysis of the depression in schizophrenia in China (DISC) study. J Affect Disord. (2021) 294:33–8. doi: 10.1016/j.jad.2021.06.075
71. Notaras, M, Lodhi, A, Dündar, F, Collier, P, Sayles, NM, Tilgner, H, et al. Schizophrenia is defined by cell-specific neuropathology and multiple neurodevelopmental mechanisms in patient-derived cerebral organoids. Mol Psychiatry. (2022) 27:1416–34. doi: 10.1038/s41380-021-01316-6
72. Hashimoto-Torii, K, Torii, M, Fujimoto, M, Nakai, A, El Fatimy, R, Mezger, V, et al. Roles of heat shock factor 1 in neuronal response to fetal environmental risks and its relevance to brain disorders. Neuron. (2014) 82:560–72. doi: 10.1016/j.neuron.2014.03.002
73. Benson, CA, Powell, HR, Liput, M, Dinham, S, Freedman, DA, Ignatowski, TA, et al. Immune factor, TNFα, disrupts human brain organoid development similar to schizophrenia-schizophrenia increases developmental vulnerability to TNFα. Front Cell Neurosci. (2020) 14:233. doi: 10.3389/fncel
74. Villanueva, R. Neurobiology of major depressive disorder. Neural Plast. (2013) 2013:873278. doi: 10.1155/2013/873278
75. Flint, J, and Kendler, KS. The Genetics of Major Depression. Neuron. (2014) 81:1214. doi: 10.1016/j.neuron.2014.02.033
76. Vadodaria, KC, Marchetto, MC, Mertens, J, and Gage, FH. Generating human serotonergic neurons in vitro: methodological advances. BioEssays. (2016) 38:1123–9. doi: 10.1002/bies.201600127
77. Fries, GR, Saldana, VA, Finnstein, J, and Rein, T. Molecular pathways of major depressive disorder converge on the synapse. Mol Psychiatry. (2023) 28:284–97. doi: 10.1038/s41380-022-01806-1
78. Vadodaria, KC, Ji, Y, Skime, M, Paquola, A, Nelson, T, Hall-Flavin, D, et al. Serotonin-induced hyperactivity in SSRI-resistant major depressive disorder patient-derived neurons. Mol Psychiatry. (2019) 24:795–807. doi: 10.1038/s41380-019-0363-y
79. Vadodaria, KC, Ji, Y, Skime, M, Paquola, AC, Nelson, T, Hall-Flavin, D, et al. Altered serotonergic circuitry in SSRI-resistant major depressive disorder patient-derived neurons. Mol Psychiatry. (2019) 24:808–18. doi: 10.1038/s41380-019-0377-5
80. Chen, WV, Nwakeze, CL, Denny, CA, O’Keeffe, S, Rieger, MA, Mountoufaris, G, et al. Pcdhαc2 is required for axonal tiling and assembly of serotonergic circuitries in mice. Science. (2017) 356:406–11. doi: 10.1126/science.aal3231
81. Cavalleri, L, Merlo Pich, E, Millan, MJ, Chiamulera, C, Kunath, T, Spano, PF, et al. Ketamine enhances structural plasticityin mouse mesencephalic and human IPSC-derived dopaminergic neurons via AMPAR-driven BDNF and MTOR signaling. Mol Psychiatry. (2018) 23:812–23. doi: 10.1038/mp.2017.241
82. Collo, G, Cavalleri, L, Chiamulera, C, and Pich, EM. (2R,6R)-hydroxynorketamine promotes dendrite outgrowth in human inducible pluripotent stem cell-derived neurons through AMPA receptor with timing and exposure compatible with ketamine infusion pharmacokinetics in humans. Neuroreport. (2018) 29:1425–30. doi: 10.1097/WNR.0000000000001131
83. Marinho, LSR, Chiarantin, GMD, Ikebara, JM, Cardoso, DS, de Lima-Vasconcellos, TH, Higa, GSV, et al. The impact of antidepressants on human neurodevelopment: brain organoids as experimental tools. Semin Cell Dev Biol. (2022) 144:67–76. doi: 10.1016/j.semcdb.2022.09.007
84. Zhong, XG, Harris, L, Smirnova, V, Zufferey, R, Sa, F, et al. Antidepressant paroxetine exerts developmental neurotoxicity in an iPSC-derived 3D human brain model Zhanj. Front Cell Neurosci. (2020) 14:25. doi: 10.3389/fncel.2020.00025
85. Osete, J.R., Akkouh, I.A., Levglevskyi, O., Vandenberghe, M., and de Assis, D.R., T Ueland and E Kondratskaya, et al. (2023). Transcriptional and functional effects of lithium in bipolar disorder iPSC-derived cortical spheroids. Mol Psychiatry doi: 10.1038/s41380-023-01944-0
86. Gordovez, FJA, and McMahon, FJ. The genetics of bipolar disorder. Mol Psychiatry. (2020) 25:544–59. doi: 10.1038/s41380-019-0634-7
87. Kim, KH, Liu, J, Galvin, RJS, Dage, JL, Egeland, JA, Smith, RC, et al. Transcriptomic analysis of induced pluripotent stem cells derived from patients with bipolar disorder from an old order Amish pedigree. PLoS One. (2015) 10:e0142693. doi: 10.1371/journal.pone.0142693
88. Chen, HM, DeLong, CJ, Bame, M, Rajapakse, I, Herron, TJ, McInnis, MG, et al. Transcripts involved in calcium signaling and telencephalic neuronal fate are altered in induced pluripotent stem cells from bipolar disorder patients. Transl Psychiatry. (2014) 4:e375. doi: 10.1038/tp.2014.12
89. Madison, JM, Zhou, F, Nigam, A, Hussain, A, Barker, DD, Nehme, R, et al. Characterization of bipolar disorder patient-specific induced pluripotent stem cells from a family reveals neurodevelopmental and mRNA expression abnormalities. Mol Psychiatry. (2015) 20:703–17. doi: 10.1038/mp.2015.7
90. Stern, S, Santos, R, Marchetto, MC, Mendes, APD, Rouleau, GA, Biesmans, S, et al. Neurons derived from patients with bipolar disorder divide into intrinsically different sub-populations of neurons, predicting the patients’ responsiveness to lithium. Mol Psychiatry. (2018) 23:1453–65. doi: 10.1038/mp.2016.260
91. Hunsberger, JG, Fessler, EB, Chibane, FL, Leng, Y, and Maric, D. Mood stabilizer-regulated MiRNAs in neuropsychiatric and neurodegenerative diseases: identifying associations and functions. Am J Transl Res. (2013) 5:450–64.
92. Bavamian, S, Mellios, N, Lalonde, J, Fass, DM, Wang, J, Sheridan, SD, et al. Dysregulation of miR-34a links neuronal development to genetic risk factors for bipolar disorder. Mol Psychiatry. (2015) 20:573–84. doi: 10.1038/mp.2014.176
93. Tobe, BTD, Crain, AM, Winquist, AM, Calabrese, B, Makihara, H, Zhao, WN, et al. Probing the lithium-response pathway in hiPSCs implicates the phosphoregulatory set-point for a cytoskeletal modulator in bipolar pathogenesis. Proc Natl Acad Sci U S A. (2017) 114:E4462–71. doi: 10.1073/pnas.1700111114
94. Zang, Z, Yin, H, Du, Z, Xie, R, and Yang, L. Valproic acid exposure decreases neurogenic potential of outer radial glia in human brain organoids. Front Mol Neurosci. (2022) 15:1023765. doi: 10.3389/fnmol.2022.1023765
95. Vadodaria, KC, Mendes, APD, Mei, A, Racha, V, Erikson, G, Shokhirev, MN, et al. Altered neuronal support and inflammatory response in bipolar disorder patient-derived astrocytes. Stem Cell Rep. (2021) 16:825–35. doi: 10.1016/j.stemcr.2021.02.004
96. Couch, ACM, Solomon, S, Duarte, RRR, Marrocu, A, Sun, Y, Sichlinger, L, et al. Acute IL-6 exposure triggers canonical IL6Ra signaling in hiPSC microglia, but not neural progenitor cells. Brain Behav Immun. (2023) 110:43–59. doi: 10.1016/j.bbi.2023.02.007
97. Fusar-Poli, P, Solmi, M, Brondino, N, Davies, C, Chae, C, Politi, P, et al. Transdiagnostic psychiatry: a systematic review. World Psychiatry. (2019) 18:192–207. doi: 10.1002/wps.20631
98. Dalgleish, T, Black, M, Johnston, D, and Bevan, A. Transdiagnostic approaches to mental health problems: current status and future directions. J Consult Clin Psychol. (2020) 88:179–95. doi: 10.1037/ccp0000482
Keywords: modeling psychiatric disorders, induced pluripotent stem cells, tridimensional neural cultures, brain organoids, organ-on-chip, transdiagnostic psychiatry
Citation: Villanueva R (2023) Advances in the knowledge and therapeutics of schizophrenia, major depression disorder, and bipolar disorder from human brain organoid research. Front. Psychiatry. 14:1178494. doi: 10.3389/fpsyt.2023.1178494
Edited by:
Cathrin Rohleder, University of Heidelberg, GermanyReviewed by:
Stewart Alan Anderson, University of Pennsylvania, United StatesCopyright © 2023 Villanueva. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Rosa Villanueva, rosvp@telefonica.net