Abstract
Human brain organoids generated with current technologies recapitulate histological features of the human brain, but they lack a reproducible topographic organization. During development, spatial topography is determined by gradients of signaling molecules released from discrete signaling centers. We hypothesized that introduction of a signaling center into forebrain organoids would specify the positional identity of neural tissue in a distance-dependent manner. Here, we present a system to trigger a Sonic Hedgehog (SHH) protein gradient in developing forebrain organoids that enables ordered self-organization along dorso-ventral and antero-posterior positional axes. SHH-patterned forebrain organoids establish major forebrain subdivisions that are positioned with in vivo-like topography. Consistent with its behavior in vivo, SHH exhibits long-range signaling activity in organoids. Finally, we use SHH-patterned cerebral organoids as a tool to study the role of cholesterol metabolism in SHH signaling. Together, this work identifies inductive signaling as an effective organizing strategy to recapitulate in vivo-like topography in human brain organoids.
Similar content being viewed by others
Main
Human pluripotent stem cells (hPSCs) have the intrinsic capacity to self-organize into multicellular organ-like structures called organoids1,2. Brain organoids recapitulate the cellular diversity and micro-architectural features characteristic of discrete brain regions, providing unprecedented opportunities to model human brain development and disease3,4,5. However, in these organoids, individual brain regions are ordered randomly and non-reproducibly and lack the characteristic in vivo anterior-posterior, dorso-ventral, and medio-lateral positioning that supports the emergence of complex brain structure and function1,4,6. The absence of a defined topography is a crucial shortcoming of current brain organoid technologies.
During brain development, topographic maps are generated by gradients of signaling activity that allow cells to acquire discrete regional identities as a function of their position7,8. Region-specific organoids attempt to overcome positional heterogeneity by restricting cellular identities to a single brain area, such as the optic cup9, adenohypophysis10, forebrain11, midbrain12, or hindbrain13, using bath-application of patterning factors14. More recently, several groups have created a dorso-ventral axis by fusing dorsal and ventral forebrain organoids15,16,17. While these strategies recapitulate some processes associated with long-range tissue interactions, such as cell migration, they fail to capture the full continuum of regional diversity encompassed by the human forebrain.
Sonic Hedgehog (SHH) is a signaling factor whose graded expression specifies the spatial organization of discrete progenitor domains across the neuraxis18,19. To test whether introduction of a SHH signaling gradient into developing forebrain organoids could specify positional domains, we engineered an inducible SHH-expressing hPSC line (iSHH) that could be embedded at one pole of a developing organoid (Fig. 1a). The iSHH line was generated by TALEN-mediated gene targeting into the AAVS1 locus of an hPSC line with constitutive RFP expression20,21. A constitutively active reverse tetracycline transactivator is expressed from one allele of the AAVS1 locus, while full-length human SHH is expressed from the other allele, under the control of a tetracycline response element (TRE) (Fig. 1a). This strategy resulted in titratable SHH expression (Fig. 1b) and commensurate post-translational palmitoylation (Supplementary Fig. 1a). The iSHH line induced robust expression of the SHH target gene FOXA2 during neural differentiation in the presence of doxycycline, indicating appropriate biological activity (Fig. 1c).
We next developed a method to embed iSHH cells at one pole of an hPSC spheroid, mimicking a developmental organizer. First, 1,000 iSHH cells were seeded in low-attachment round bottom microwells and allowed to aggregate for 24 h (day −2 to −1). The next day 10,000 wild-type H9 hPSC were seeded on top of the iSHH cells (day −1 to 0) and allowed to aggregate for another 24 h, resulting in a reproducible chimeric iSHH-H9 spheroid in which a small cluster of iSHH cells are embedded within a larger spheroid (Supplementary Fig. 1b, > 90% efficiency). We refer to these chimeric 3D hPSC cultures as SHH-spheroids. For the specific induction of forebrain identity, we devised a strategy that combines aspects of several previous organoid induction protocols. In brief, SHH-spheroids were cultured in the presence of inhibitors of TGFβ, BMP, and WNT (3-inhibitor protocol) for 6–8 d to promote specification of anterior forebrain identity11. After 6–8 d of differentiation, spheroids were embedded in matrigel droplets to promote neuroepithelial organization and moved to an orbital shaker upon outgrowth of neuroepithelial buds, which was typically 4–6 d4 (Supplementary Fig. 1c). Doxycycline (400 ng/ml) was added to the differentiation medium starting at day 0 to induce an asymmetric SHH signal (Fig. 1d). Under those conditions, the iSHH-organizer typically remained positioned at one end of the developing organoid, though we observed small clusters of organizer cells separated from the main organizer in 25% of instances (Supplementary Fig. 1d). To assess whether this strategy generates a gradient of SHH protein, we performed immunocytochemistry at day 4 of the differentiation. In the absence of doxycycline, no SHH protein was detectable. In the presence of doxycycline, high levels of SHH expression were detected in the region of the iSHH cells, and the abundance of SHH protein was reduced as a function of distance from the SHH-organizer (Fig. 1e,f).
Functional subdivisions in the mammalian forebrain are located at discrete positions within a Cartesian coordinate system, whose axes are arranged in the dorso-ventral, medio-lateral, and antero-posterior directions. Each of the dorso-ventral and antero-posterior domains can be identified by the expression of characteristic transcription factors. PAX6 is expressed in the dorsal forebrain and NKX2.1 in the ventral forebrain (Fig. 1g). FOXG1 is expressed in the anterior forebrain, or telencephalon, while it is absent from the posterior forebrain, or diencephalon. In contrast, OTX2 is expressed in the diencephalon (Fig. 1h). When we differentiated H9 spheroids or SHH-spheroids in the absence of doxycycline, they predominantly expressed PAX6 and FOXG1 within self-organized neuroepithelium, in agreement with previous findings11 (Fig. 1g,h). This indicates that the default identity of our 3D cultures is dorsal-anterior forebrain, which gives rise to the neocortex. SHH-spheroids grown in the presence of doxycycline (400 ng/ml) induced NKX2.1 near the organizer, while PAX6 expression was suppressed (Fig. 1g).
Surprisingly, FOXG1 expression was also suppressed near the organizer, while OTX2 expression was maintained (Fig. 1h), suggesting that SHH can lead to posterior forebrain specification. We therefore examined the expression of TCF7L2, which is expressed in the diencephalon22,23 and SIX324, which is expressed in optic recess and hypothalamus, in SHH-organoids. Both TCF7L2 and SIX3 were induced near organizer tissue (Fig. 1i), supporting a role for SHH in anterior-posterior patterning, as well as dorsoventral patterning. SHH exhibited dose-dependent induction of DKK1 (Fig. 1j), a secreted antagonist that shapes the anterior-posterior WNT gradient in vivo, that is commonly induced in regions of high WNT/β-catenin activity and that is a critical regulator of anterior-posterior patterning25,26,27. Thus, SHH might exert anterior-posterior patterning activity via regulation of WNT signaling28.
Given that a SHH protein gradient could specify distinct dorso-ventral and antero-posterior positional domains, we next sought to determine whether the resulting forebrain subdivisions were aligned according to an anatomically appropriate topography. The position of the presumptive forebrain subdivisions in vivo can be defined by their distance from the SHH source in the hypothalamus. The neocortex (PAX6+/FOXG1+) represents the anterior and dorsal subdivision of the forebrain, which is located most distal from the SHH source. Just ventral to the neocortex is the lateral ganglionic eminence (LGE), characterized by the co-expression of GSH2 and FOXG1, followed by the medial ganglionic eminence (MGE), characterized by co-expression of NKX2.1 and FOXG1, the antero-dorsal hypothalamus, characterized by expression of NKX2.2, and finally the ventro-posterior hypothalamus, characterized by the expression of NKX2.1 and absence of FOXG1, representing the brain region located most ventral and proximal to the SHH source (Fig. 2a).
When differentiated in the presence of doxycycline (400 ng/ml), SHH-spheroids formed at least five topographically distinct presumptive forebrain domains. Quantification of the distance of forebrain domains from the SHH-organizer (Supplementary Fig. 2), identified by protein expression, revealed that the positioning of these domains mimics the pattern observed in vivo (Fig. 2b). Topographic organization could be triggered in a similar manner in at least five additional hPSC or iPSC lines using the same H9-based iSHH organizer, though the specific growth rates and size of regional domains could differ (Supplementary Fig. 3). We next identified presumptive neocortical (FOXG1+/PAX6+), LGE (GSH2+), MGE (FOXG1+/NKX2.1+), anterior hypothalamic (NKX2.2+) and ventro-posterior hypothalamic (NKX2.1+/FOXG1–) regions by immunocytochemistry (Fig. 2c). FOXG1 expression was absent from the organizer tissue itself, but robust expression of NKX2.1 was observed in at least a subset of the organizer cells, suggesting hypothalamic identity29 (Supplementary Fig. 4a). The resulting topographic patterning is in contrast to the patterning exerted by bath application of SHH agonist to forebrain organoids, which results in subpallium-restricted identities15,16. Topographic patterning could also be achieved in the absence of matrigel (Supplementary Fig. 4b). SHH-spheroids differentiated in the absence of doxycycline expressed markers of dorsal-anterior forebrain, including PAX6 and FOXG1, with a small proportion of GSH2 expressing cells. These 3D cultures in the absence of doxycycline did not express the ventral identity genes NKX2.1 and NKX2.2 (Fig. 2d).
Interestingly, tissue cytoarchitecture differed between areas that are proximal (hypothalamic-like) and distal (telencephalic-like) to the SHH source. At day 20, PAX6+ distal neuroepithelia acquired circular, rosette-like morphologies (Fig. 2e, inset), consistent with the self-organizing radial structures described for forebrain organoids4,11. In contrast, the NKX2.1+ proximal region contained many thin and highly extended neuroepithelia (Fig. 2e, inset) as observed previously for 3D structures of early hypothalamic lineages10,30. This appears to be restricted to diencephalic NKX2.1+ regions, as presumptive MGE domains (FOXG1+/NKX2.1+) typically acquired circular, rosette-like morphologies (Fig. 2c and Supplementary Fig. 4c). Our data indicate that an asymmetric SHH cue enables the ordered patterning and topographical organization of brain regions without interfering in the self-organization process, which leads to the establishment of region-specific tissue microarchitectures. We term these 3D cultures SHH-organoids.
To explore the degree to which topography is maintained over time, we cultured SHH-organoids for up to 70 d. FOXG1+ and OTX2+ domains remained largely discrete at this stage, typically with the OTX2+ domain located proximal to the organizer, while the FOXG1+ domain was located distal to the organizer (Supplementary Fig. 5a). Radially organized PAX6, TBR2, TBR1 cerebral cortex-like tissue and DARPP32+ striatum-like tissue emerged in distal domains (Supplementary Fig. 5b–d), while hypothalamic-like tissue, expressing LHX6, OTP, POMC, and TH, was found in the immediate vicinity of the organizer cells (Supplementary Fig. 5d–f). In some instances organoid topography was more difficult to discern because the organizer seemed to have dispersed throughout the tissue. In addition, tissue necrosis in the center of those larger organoids may degrade organization over time.
The identity of LHX6+ cells including the presence of cortical interneurons was further defined by differentiating SHH-organoids using an LHX6-citrine hPSC line. As expected, LHX6+ , putative hypothalamic precursors, emerge near the organizer, with some cells co-expressing NKX2.1 (Supplementary Fig. 6a). A subset of LHX6+ cells co-expresses FOXG1 (Supplementary Fig. 6b), while a subset is negative for FOXG1, suggesting the presence of both MGE and hypothalamic LHX6 lineages. Some FOXG1+/LHX6+ cells exhibit a leading-process morphology characteristic of migrating interneurons (Supplementary Fig. 6c). Cells expressing SST, PV, or CR were observed in SHH-organoids (Supplementary Fig. 6d–f), suggesting the emergence of diverse interneuron populations. However, PV+ cells did not co-express LHX6 indicating that those PV+ cells many not represent cortical interneurons.
We next sought insight into the mechanisms by which a SHH signaling gradient establishes forebrain topography. Using the suppression of PAX6 as a read-out of SHH signaling activity, we compared the radial extent of PAX6 suppression in 2D versus 3D cultures. High-doxycycline conditions (2 μg/ml) were used in assessing SHH activity. In 3D cultures, we observe the suppression of PAX6 expression at an average distance of 335 ± 54 μm from the organizer tissue (Fig. 3a). Interestingly, this range is similar to the distances reported for SHH signaling in vivo based on studies across multiple tissues of the developing mouse or chick embryos31,32,33. However, in 2D cultures in which a similar 1:10 ratio of iSHH to wild-type cells is maintained, we saw suppression of PAX6 at much shorter average distances (75 ± 31 μm) from the SHH source tissue (Fig. 3a).
The observation that the range of SHH signaling activity is restricted in 2D raises the question how SHH establishes long-range gradients in 3D. We generated 2 theoretical models based on known mechanisms of SHH signaling in vivo (Fig. 3b). The first model is a concentration-dependent model. In this model, SHH signaling activity is determined by the local concentration of SHH morphogen, and is dependent on mechanisms that can transport SHH protein over long distances, such as diffusion, facilitated transport, or cell-to-cell relay31,33,34,35,36,37. The second model is a temporal model. In this model, SHH signaling is restricted to tissue immediately adjacent to the source, which is relieved of SHH signaling as tissue grows away from the source38. Tissue that grows away from a SHH source will record a brief duration of signaling activity, while tissue that remains near the SHH source will record a long duration of signaling activity. This temporal model does not rely on transport of SHH over long distances.
To experimentally test these models, we embedded the iSHH organizer within a circumscribed ring of GFP-expressing hPSCs. This was achieved by sequential plating of 1,000 iSHH cells, followed by 1,000 GFP cells 8 h later, followed by 10,000 H9 cells the next day. We reasoned that if the activity of SHH extends past the GFP boundary, this would support a long-range concentration-dependent mechanism. On the other hand, if the GFP boundary expands coincident with the extent of SHH activity, this would support a temporal model in which tissue growth rather than protein transport establishes long-range SHH activity (Fig. 3b). After growing SHH-GFP-organoids for 20 d in doxycycline (2 μg/ml), we observed that the GFP-expressing cells stayed within 285 ± 44 μm to the SHH organizer cells. The activity of SHH, determined as suppression of PAX6 expression, extended to 430 ± 96 μm, past the green boundary (Fig. 3c). These data provide evidence for a concentration-dependent signaling mechanism in which SHH protein is transported long distances away from producing cells. Still, because the long-range SHH signal degrades in 2D culture while a short-range signal persists, our data do not exclude the possibility of a concurrent short-range signaling mechanism in which the activity SHH is restricted to the immediate vicinity of producing cells. In fact, during limb patterning, SHH is known to act by both short- and long-range signaling mechanisms, and such an interplay of short- and long-range signaling may also be critical during forebrain development29,39,40,41.
The reproducible topography of SHH-organoids might make them suitable as a tool to study signaling mechanisms during early forebrain patterning. Cholesterol is integrally linked to the SHH pathway in many ways. Cholesterol is an agonist of the smoothened receptor42,43. SHH long-range signaling is dependent on the cholesterol post-translational modification of SHH34,35,44, cholesterol rich lipid rafts36,45,46, and can be facilitated by cholesterol-rich macromolecular soluble complexes47,48.
To explore the multifaceted relationship of cholesterol to SHH signaling, we treated SHH-organoids (400 ng/ml doxycycline) from days 0–10 with small molecules that inhibit cholesterol synthesis at different points along the biosynthetic pathway (Fig. 4a). AY9944 is a specific inhibitor of 7-dehydrocholesterol reductase (DHCR7), which facilitates the terminal step of cholesterol synthesis. Lovastatin is an inhibitor of HMG-CoA reductase, an early step in cholesterol biosynthesis. Cyclopamine, a Smoothened antagonist that blocks all SHH activity, was used as a control. At day 20 in the no drug condition, SHH-organoids established distinct positional domains marked by the expression of PAX6, GSH2, NKX2.2, and NKX2.1 at discrete distances from the SHH-organizer (Fig. 4b). As expected, SHH-organoids grown in the presence of cyclopamine (1 μM49) were nearly uniform for PAX6 expression, with some GSH2 expression, consistent with a near complete inhibition of SHH signaling activity (Fig. 4b,c). AY9944 (1.25 μM50) treatment reduced the efficacy and range of SHH signaling activity, shifting the organoid to a more dorsal identity. NKX2.2 induction was largely blocked, while cells just adjacent to the organizer expressed GSH2 and PAX6 (Fig. 4b,c). Lovastatin (5 μM50) treatment caused similar, but milder effects, than AY9944. There was a partial block in NKX2.2 induction, with concomitant increase in GSH2 expression (Fig. 4b,c), consistent with a dorsal shift and reduction in the efficacy and range of SHH signaling activity. Notably, the organizer cells retained diencephalic NKX2.1 expression in the presence of AY9944 or lovastatin but not cyclopamine (Supplementary Fig. 7a), suggesting that inhibition of cholesterol synthesis has minimal impact on local SHH activity.
In addition to the effects on patterning, all drugs affected organoid growth. Overall organoid size was reduced in all treatment conditions (Fig. 4b,c). However, AY9944 and lovastatin did not reduce the size of the organizer itself (Supplementary Fig. 7b), consistent with the interpretation that cholesterol-synthesis inhibition has differential effects on local and long-range SHH activity. To dissociate growth and patterning phenotypes, we analyzed organoids at day 6, during the early stages of SHH patterning, and prior to the major phase of tissue growth (which occurs after matrigel embedding). We used NKX2.2, a direct target of GLI51, as a read-out of SHH signaling activity. By measuring the distance at which NKX2.2 is expressed from the SHH producing cells, we could infer the distance of SHH signaling activity. Lovastatin reduced the distance at which NKX2.2 is induced from the organizer in a dose-dependent manner (Fig. 4d). AY9944 strongly inhibited NKX2.2 induction at all concentrations tested (Supplementary Fig. 7c). Neither AY9944 nor lovastatin grossly perturbed processing of SHH peptide length (Supplementary Fig. 7d). Together, these data support a model in which inhibition of cholesterol synthesis by lovastatin or AY9944 result in a complex developmental phenotype characterized by impaired growth and a reduction in the range of SHH signaling activity, though perhaps in distinct ways.
This study reveals that an asymmetric morphogenetic cue provides positional information from which in vivo-like topography can emerge in brain organoids. Furthermore, we present evidence that SHH uses a long-range signaling mechanism during forebrain organoid development, recapitulating its in vivo behavior40. The emergence of long-range activity in 3D that is not present in 2D cultures highlights the importance of tissue geometry on the spatial dynamics of signaling activity.
The strategy of generating topographically patterned organoids allowed us to investigate how alterations in cholesterol metabolism perturb SHH-dependent patterning. Our data suggest that while both AY9944 and lovastatin impair SHH-dependent patterning, they may do so in different ways. AY9944 has previously been shown to block Smoothened activation50, consistent with the reduction in NKX2.2 induction at day 6 (Supplementary Fig. 7c). On the other hand, lovastatin reduced the range of SHH signaling at day 6 without reducing the intensity of signaling. While future studies are required to determine mechanism of action, there are multiple possible explanations for this observation. First, statin treatment could disrupt lipid raft integrity52,53,54,55,56, which is required for long-range hedgehog signaling46 and perhaps SHH oligomerization at the membrane57,58. Second, statins could lead to removal of the C-terminal SHH cholesterol modification, which is required for long-range signaling34,35,44. While it is unlikely that statins block the initial cholesterylation of SHH during auto-cleavage59, SHH can subsequently lose its C-terminal cholesterol through proteolytic cleavage, or ‘shedding’, at the cell membrane60. Notably, disruption of lipid rafts by sterol-reduction, either with statins or methyl-β-cyclodextrin, increases shedding of multiple membrane-associated proteins, including SHH52,53,60. Third, statin treatment could reduce the formation of cholesterol-rich multimeric SHH complexes involved in long-range transport47,48. Finally, it is possible that statins perturb SHH patterning through isoprenoid pathway inhibition or off-target effects given the high concentration of drug used. Statins have been reported to be associated with fetal maldevelopment, including holoprosencephaly, in a small number of cases61. Our data suggest that some of these cases may be due to impaired SHH signaling, although caution must be exercised given the high concentration of statin used in our experiments (5 μM) compared to the typical plasma concentration of statin (15–20 nM)62.
A key feature of the patterning strategy presented here is the establishment of well-ordered positional domains during early organoid development. In future studies it will be important to determine the extent to which the topography of these domains can be retained during long-term in vitro culture for the study of region-specific neuronal diversity as well as connectivity and function. It is possible that additional tissue engineering approaches will be required to facilitate the maintenance of topography over time and to prevent increasing cell mixing or inappropriate migration, processes that could blur the boundaries between positional domains over time. For example, manipulating soluble ECM components has been used to improve the maintenance of radially organized structures within organoids over time63.
For disease modeling, current organoid technologies have been successful at modeling cortical progenitor dynamics that ultimately result in changes in brain size. Pre-patterning and fusion of pallial- and subpallial-specific spheroids have been used to study specific phenotypes related to cortical interneuron migration and connectivity16. The establishment of forebrain topography in organoids shown here opens the possibility of studying a wide range of phenotypes in a single organoid system. In particular, it would be interesting to study complex neurodevelopmental diseases that have been hypothesized to alter or derive from regional specification during forebrain patterning, including autism64, epilepsy65, or suprasellar pediatric gliomas66. In the future it will important to develop strategies such as bio-engineering approaches to reduce the variability of topography in long-term cultures. Finally, it will be exciting to test whether our strategy could be used as a general approach to establish topographies across all regions of the CNS beyond the forebrain.
Methods
hPSC maintenance and monolayer differentiation
hPSC (H9 and derivatives (EF1α::GFP (GFP), EF1 α::RFP; TRE-SHH (iSHH), MEL1, HUES6, HUES8, LHX6-citrine67) and iPSC (J1 and 348) were maintained with Essential 8 medium or Essential 8 flex (E8, Thermo, A15117001 or A28558501) in feeder-free conditions on vitronectin (VTN-N) substrate (Thermo, A14700). hPSCs were passaged as clumps with EDTA solution (0.5 M EDTA/PBS). For neural monolayer differentiation, hPSCs were dissociated to single cells and plated on matrigel substrate (BD Biosciences, 354234) in E8 at a density of 250,000 cells/cm2 in the presence of ROCK inhibitor (Y-27632, 10 μM, Tocris 1254) (day −1). From days 0 to 7, cells were cultured in Essential 6 medium (E6, Thermo, A1516401) in the presence of TGFβ and BMP inhibitors (LDN193189, 100 nM, Stem Cell Technologies, 72142; SB431542, 10 μM, Tocris, 1614). From days 7 to 12, cells were cultured in E6 alone. Floorplate was specified by addition of SHH (200 ng/ml, R&D Systems 464-SH) and CHIR99021 (0.7 μM, Tocris 4423). Medium was changed every day during the differentiation.
SHH inducible line
The iSHH hPSC was generated according to a previously described gene targeting strategy21. Briefly, two donor constructs were targeted to the first intron of the AAVS1 locus using TALEN-facilitated homologous recombination. One construct contained a constitutively expressed reverse tetracycline transactivator (M2rtTA) and the second construct contained a tetracycline inducible (TRE) SHH cassette. The SHH cassette was generated using full length human SHH cDNA (Genecopoeia T1004). Targeting was performed in a constitutive RFP expressing line (WA09 derived, EF1α::RFP) so iSHH cells could be visualized20.
SHH-spheroid aggregation
1,000 iSHH cells were dissociated to single cell and aggregated in low-attachment round bottom microwells for 24 h in the presence of ROCK inhibitor (Y-27632, 10 μM) and WNT inhibitor (XAV939, 5 μM). For Fig. 3c, the GFP boundary was established by first plating iSHH cells and allowing them to aggregate for 8 h. 1,000 GFP cells were then plated on top and allowed to aggregate overnight. The next day, 10,000 wildtype H9 hPSCs were dissociated to single cell and allowed to aggregate on top of the iSHH cells, in E8 medium with ROCK inhibitor (Y-27632, 10 μM) and WNT inhibitor (XAV939, 5 μM, Tocris 3748).
SHH-organoid differentiation
SHH-spheroids were cultured in E6 with 3-inhibitors (LDN193189, 100 nM; SB431542, 10 μM; XAV939, 5 μM) plus doxycycline (400 ng/mL) until spheroid tissue began to brighten and have smooth edges, typically 6–8 d. SHH-spheroids were then embedded in matrigel drops and cultured in a N2/B27 based organoid medium as previously described68, except NeuroBrew B21 (Miltenyi Biotec) was substituted for B27. SHH-spheroids were moved to an orbital shaker once formation of translucent, neuroepithelial buds was observed, typically 4–7 d after embedding. Organoids that failed to form translucent, neuroepithelial buds were discarded. Half of the medium was changed every other day.
Histology and immunocytochemistry
Day 20 organoids were fixed in 4% PFA overnight at 4 °C, and washed three times with PBS the next day. After fixation, tissue was cryoprotected in 30% sucrose/PBS and sectioned at 30μm on a cryostat (Leica 3050 S). Sections were blocked for 30 min in 10% FBS, 1% BSA, 0.3%triton in PBS, and incubated as floating section in primary antibody overnight (see Supplementary Table 1). The next day, sections were washed with PBS and incubated as floating section in secondary antibody for 3 h at room temperature. Day 6 organoids were fixed in 4% PFA for 2 h at 4 °C, and washed three times with PBS. After fixation, tissue was cryoprotected in 30% sucrose/PBS and sectioned at 20 μm and mounted directly onto slides prior to immunofluorescence assays.
Quantification of organoid patterning and SHH activity
Organoid topography was quantified by first dividing each image into a grid of 20 μm × 20 μm squares (day 20 analysis) or 5 μm × 5 μm squares (day 6 analysis) that form a Cartesian coordinate grid. Each square is a discrete region of interest (ROI) that is associated with an x and y coordinate. The origin of the grid was calculated for each image as the “center of mass” of the iSHH-organizer cells: CMx = Σ mixi / M and CMy = Σ miyi / M, where m is the gray value intensity of iSHH cells for individual ROIs, x or y is the coordinate, and M is the total intensity for all ROIs, and the sum includes all x or y coordinates in the image. Next, ROI’s that were positive for expression of a given protein (e.g. PAX6) were defined by thresholding staining intensity and determining ROIs with positive immunoreactivity. The linear distance from the origin to each ROI (sqrt((ROIx – CMx)2 + (ROIy – CMy)2)) was calculated. We attempted to analyze every sixth section for each regional marker per organoid (2–5 sections typically), thus sampling the organoids in 150 μm intervals using uniform random sampling.
In Figs. 2c and 4d ROI frequencies are plotted as a function of distance from the center of mass. In Fig. 3c the GFP shell distance is defined as the radial distance from the center of mass at which the ratio of GFP ROIs / DAPI ROIs drops below 35%. The SHH-activity distance is the radial distance from the center of mass to the edge of the PAX6-negative territory, defined as the distance at which the ratio of PAX6-negative ROIs / DAPI ROIs dropped below 95% (PAX6-negative ROIs were obtained by subtracting PAX6 thresholded pixels from DAPI thresholded pixels). The 35 and 95% parameters were determined prior to analysis as accurately cut off values by comparing with manual distance measurements. Area measurements in Fig. 4b are determined by calculating the number of positive ROIs positive for a given gene (e.g. PAX6) divided by the ROIs positive for DAPI. Exclusion criteria for analysis: 1) organoid batches that failed to induce FOXG1 expression (Supplementary Fig. 2b), 2) organoids containing a split organizer, in which we observe two independent patterning centers (Supplementary Fig. 2c), 3) Sections that lacked organizer cells, a center of mass could not be defined, and 4) sections that had large necrotic centers as this could confound distance analysis.
The distance of SHH patterning activity in Fig. 3a was obtained by measuring the distance of lines from the edge of PAX6 territory to the nearest organizer cells. At least 5 lines were measured per section. All quantifications were performed using ImageJ.
Microscopy was performed using a standard inverted epifluorescence microscope (Olympus IX71 or Zeiss Axio Observer). Images were acquired using Cell Sens (Olympus) or Zen Pro (Zeiss) software. Min, max and gamma (midtone) adjustments were applied uniformly to images during processing with Adobe Photoshop Creative Cloud.
RNA extraction and RT-PCR
RNA was extracted using TRIzol (Invitrogen, 15596026) followed by chloroform extraction. RNA was precipitated in isopropanol and resuspended in nuclease free ddH2O. cDNA synthesis was performed using 1 μg of RNA (iScript, Bio-Rad, 1708840). RT-PCR was performed with EvaGreen Supermix (Bio-Rad, 1725202). Three to four individual samples were combined into a single replicate when collecting RNA from spheroids.
Visualization of SHH protein gradient
SHH-spheroids were fixed in 4% PFA for 6 h at 4 C, then washed three times in PBS. Standard immunocytochemistry was performed on wholemount SHH-spheroids using anti-SHH primary antibody (1:100, clone 5E1, DSHB). Secondary antibody was amplified using a tyramide signal amplification kit (Thermo, B40941). Fluorescence labeled spheroids were visualized using an inverted epifluorescence microscope. Gradients were quantified using line scans that transected the organizer tissue. Quantifications were performed using ImageJ.
Cell-based SHH palmitoylation assay
Synthesis of [I125]iodopalmitate was carried out as previously described69,70,71. iSHH hPSC were dissociated to single cell and seeded as a confluent monolayer on matrigel substrate at a density of 250,000 cells / cm2 and differentiated for 9 d in E6 with LDN193189, (100 nM) and SB431542 (10 μM) at increasing concentrations of doxycycline (0, 125, 250, 500, 1000, 2000 ng/ml). On day 9, iSHH cells were incubated for 1 h at 37 °C with DMEM containing 2% dialyzed FBS and then labeled for 4 h with 10 μCi of [I125]iodopalmitate. The cells were lysed and subjected to immunoprecipitation with an anti-SHH antibody, and the immunoprecipitates were diluted in 100 μl of 2 × SDS-PAGE sample buffer containing 10 mM DTT. The samples were analyzed on a 12.5% SDS-PAGE gel, followed by phosphorimaging on a Typhoon FLA-7000 phosphorimager. An aliquot of each immunoprecipitate was analyzed for SHH protein expression by Western blotting.
SHH western blot
Cells were harvested and washed with PBS. Cell pellets were lysed in RIPA buffer (Boston Bioproducts Inc. NC9517624) supplemented with protease inhibitors (Thermo 78425) and ran through a syringe several times. Lysate was incubated for 30 min on ice and then centrifuged to isolate the supernatant. For quantification of protein concentration, 3 ul of lysate was added to 300 ul of Precision Red (Cytoskeleton, Inc. ADV02-A) and absorbance (600 nm) was read on a plate reader and the concentration was calculated by: (Abssample – Absbackground) x 12.5. For Western blots, 10 μg of protein was resuspended in 2X Laemmli buffer and denatured at 100 C for 5 min. Samples were loaded and run on a 4–12% pre-cast Bis-Tris gel (Thermo NP0322BOX) and transferred overnight onto Nitrocellulose membrane (Thermo 88018). Membranes were blocked in 5% milk and primary antibodies were incubated overnight at 4 C. Blots were visualized using ECL (Perkin Elmer NEL104001EA).
Statistical analysis
All reported measurements are from distinct samples. When comparing samples across treatment groups, samples were collected, processed, and analyzed in parallel. In the figure legends, “N” refers to an independent biological replicate (e.g. single organoid or single monolayer culture). “Organoid” refers to an individual, distinct organoid from 1 well of culture dish. “Batch” refers to a group of organoids that were differentiated in the same dish on the same day. See Life Sciences Reporting Summary for more details. Statistical tests and biological replicates for each experiment are listed in the figure legends and in Supplementary Table 2.
Reporting Summary
Further information on research design is available in the Nature Research Reporting Summary linked to this article.
Data Availability
The data that support the findings of this study are available from the corresponding author upon reasonable request.
References
Kelava, I. & Lancaster, M. A. Stem cell models of human brain development. Cell Stem Cell 18, 736–748 (2016).
Sasai, Y., Eiraku, M. & Suga, H. In vitro organogenesis in three dimensions: self-organising stem cells. Development 139, 4111–4121 (2012).
Lancaster, M. A. & Knoblich, J. A. Organogenesis in a dish: modeling development and disease using organoid technologies. Science 345, 1247125 (2014).
Lancaster, M. A. et al. Cerebral organoids model human brain development and microcephaly. Nature 501, 373–379 (2013).
Quadrato, G., Brown, J. & Arlotta, P. The promises and challenges of human brain organoids as models of neuropsychiatric disease. Nat. Med. 22, 1220–1228 (2016).
Renner, M. et al. Self-organized developmental patterning and differentiation in cerebral organoids. EMBO J. 36, 1316–1329 (2017).
O’Leary, D. D., Chou, S. J. & Sahara, S. Area patterning of the mammalian cortex. Neuron 56, 252–269 (2007).
Sagner, A. & Briscoe, J. Morphogen interpretation: concentration, time, competence, and signaling dynamics. Wiley Interdiscip. Rev. Dev. Biol. 6, https://doi.org/10.1002/wdev.271 (2017).
Eiraku, M. et al. Self-organizing optic-cup morphogenesis in three-dimensional culture. Nature 472, 51–56 (2011).
Suga, H. et al. Self-formation of functional adenohypophysis in three-dimensional culture. Nature 480, 57–62 (2011).
Kadoshima, T. et al. Self-organization of axial polarity, inside-out layer pattern, and species-specific progenitor dynamics in human ES cell-derived neocortex. Proc. Natl Acad. Sci. USA 110, 20284–20289 (2013).
Jo, J. et al. Midbrain-like organoids from human pluripotent stem cells contain functional dopaminergic and neuromelanin-producing neurons. Cell Stem Cell 19, 248–257 (2016).
Muguruma, K., Nishiyama, A., Kawakami, H., Hashimoto, K. & Sasai, Y. Self-organization of polarized cerebellar tissue in 3D culture of human pluripotent stem cells. Cell Rep. 10, 537–550 (2015).
Qian, X. et al. Brain-region-specific organoids using mini-bioreactors for modeling ZIKV exposure. Cell 165, 1238–1254 (2016).
Bagley, J. A., Reumann, D., Bian, S., Levi-Strauss, J. & Knoblich, J. A. Fused cerebral organoids model interactions between brain regions. Nat. Methods 14, 743–751 (2017).
Birey, F. et al. Assembly of functionally integrated human forebrain spheroids. Nature 545, 54–59 (2017).
Xiang, Y. et al. Fusion of Regionally Specified hPSC-Derived Organoids Models Human Brain Development and Interneuron Migration. Cell Stem Cell 21, 383–398.e387 (2017).
Lupo, G., Harris, W. A. & Lewis, K. E. Mechanisms of ventral patterning in the vertebrate nervous system. Nat. Rev. Neurosci. 7, 103–114 (2006).
Jessell, T. M. Neuronal specification in the spinal cord: inductive signals and transcriptional codes. Nat. Rev. Genet. 1, 20–29 (2000).
Fattahi, F. et al. Deriving human ENS lineages for cell therapy and drug discovery in Hirschsprung disease. Nature 531, 105–109 (2016).
Gonzalez, F. et al. An iCRISPR platform for rapid, multiplexable, and inducible genome editing in human pluripotent stem cells. Cell Stem Cell 15, 215–226 (2014).
Shiraishi, A., Muguruma, K. & Sasai, Y. Generation of thalamic neurons from mouse embryonic stem cells. Development 144, 1211–1220 (2017).
Merchan, P., Bardet, S. M., Puelles, L. & Ferran, J. L. Comparison of pretectal genoarchitectonic pattern between quail and chicken embryos. Front. Neuroanat. 5, 23 (2011).
Oliver, G. et al. Six3, a murine homologue of the sine oculis gene, demarcates the most anterior border of the developing neural plate and is expressed during eye development. Development 121, 4045–4055 (1995).
Shinya, M., Eschbach, C., Clark, M., Lehrach, H. & Furutani-Seiki, M. Zebrafish Dkk1, induced by the pre-MBT Wnt signaling, is secreted from the prechordal plate and patterns the anterior neural plate. Mech. Dev. 98, 3–17 (2000).
Houart, C. et al. Establishment of the telencephalon during gastrulation by local antagonism of Wnt signaling. Neuron 35, 255–265 (2002).
Kiecker, C. & Niehrs, C. A morphogen gradient of Wnt/beta-catenin signalling regulates anteroposterior neural patterning in Xenopus. Development 128, 4189–4201 (2001).
Maroof, A. M. et al. Directed differentiation and functional maturation of cortical interneurons from human embryonic stem cells. Cell Stem Cell 12, 559–572 (2013).
Blaess, S., Szabo, N., Haddad-Tovolli, R., Zhou, X. & Alvarez-Bolado, G. Sonic hedgehog signaling in the development of the mouse hypothalamus. Front. Neuroanat. 8, 156 (2014).
Merkle, F. T. et al. Generation of neuropeptidergic hypothalamic neurons from human pluripotent stem cells. Development 142, 633–643 (2015).
Briscoe, J., Chen, Y., Jessell, T. M. & Struhl, G. A hedgehog-insensitive form of patched provides evidence for direct long-range morphogen activity of sonic hedgehog in the neural tube. Mol. Cell 7, 1279–1291 (2001).
Honig, L. S. Positional signal transmission in the developing chick limb. Nature 291, 72–73 (1981).
Fan, C. M. & Tessier-Lavigne, M. Patterning of mammalian somites by surface ectoderm and notochord: evidence for sclerotome induction by a hedgehog homolog. Cell 79, 1175–1186 (1994).
Zeng, X. et al. A freely diffusible form of Sonic hedgehog mediates long-range signalling. Nature 411, 716–720 (2001).
Lewis, P. M. et al. Cholesterol modification of sonic hedgehog is required for long-range signaling activity and effective modulation of signaling by Ptc1. Cell 105, 599–612 (2001).
Chen, M. H., Li, Y. J., Kawakami, T., Xu, S. M. & Chuang, P. T. Palmitoylation is required for the production of a soluble multimeric Hedgehog protein complex and long-range signaling in vertebrates. Genes Dev. 18, 641–659 (2004).
Sanders, T. A., Llagostera, E. & Barna, M. Specialized filopodia direct long-range transport of SHH during vertebrate tissue patterning. Nature 497, 628–632 (2013).
Harfe, B. D. et al. Evidence for an expansion-based temporal Shh gradient in specifying vertebrate digit identities. Cell 118, 517–528 (2004).
Zhang, Y. & Alvarez-Bolado, G. Differential developmental strategies by Sonic hedgehog in thalamus and hypothalamus. J. Chem. Neuroanat. 75, 20–27 (2016).
McGlinn, E. & Tabin, C. J. Mechanistic insight into how Shh patterns the vertebrate limb. Curr. Opin. Genet. Dev. 16, 426–432 (2006).
Ericson, J. et al. Sonic hedgehog induces the differentiation of ventral forebrain neurons: a common signal for ventral patterning within the neural tube. Cell 81, 747–756 (1995).
Huang, P. et al. Cellular cholesterol directly activates Smoothened in Hedgehog signaling. Cell 166, 1176–1187 e1114 (2016).
Byrne, E. F. X. et al. Structural basis of Smoothened regulation by its extracellular domains. Nature 535, 517–522 (2016).
Tian, H., Jeong, J., Harfe, B. D., Tabin, C. J. & McMahon, A. P. Mouse Disp1 is required in sonic hedgehog-expressing cells for paracrine activity of the cholesterol-modified ligand. Development 132, 133–142 (2005).
Rietveld, A., Neutz, S., Simons, K. & Eaton, S. Association of sterol- and glycosylphosphatidylinositol-linked proteins with Drosophila raft lipid microdomains. J. Biol. Chem. 274, 12049–12054 (1999).
Katanaev, V. L. et al. Reggie-1/flotillin-2 promotes secretion of the long-range signalling forms of Wingless and Hedgehog in Drosophila. EMBO J. 27, 509–521 (2008).
Panakova, D., Sprong, H., Marois, E., Thiele, C. & Eaton, S. Lipoprotein particles are required for Hedgehog and Wingless signalling. Nature 435, 58–65 (2005).
Palm, W. et al. Lipoproteins in Drosophila melanogaster–assembly, function, and influence on tissue lipid composition. PLoS Genet. 8, e1002828 (2012).
Gaspard, N. et al. An intrinsic mechanism of corticogenesis from embryonic stem cells. Nature 455, 351–357 (2008).
Blassberg, R., Macrae, J. I., Briscoe, J. & Jacob, J. Reduced cholesterol levels impair Smoothened activation in Smith-Lemli-Opitz syndrome. Hum. Mol. Genet. 25, 693–705 (2016).
Lei, Q. et al. Wnt signaling inhibitors regulate the transcriptional response to morphogenetic Shh-Gli signaling in the neural tube. Dev. Cell 11, 325–337 (2006).
von Tresckow, B. et al. Depletion of cellular cholesterol and lipid rafts increases shedding of CD30. J. Immunol. 172, 4324–4331 (2004).
Murai, T. et al. Low cholesterol triggers membrane microdomain-dependent CD44 shedding and suppresses tumor cell migration. J. Biol. Chem. 286, 1999–2007 (2011).
Kirsch, C., Eckert, G. P. & Mueller, W. E. Statin effects on cholesterol micro-domains in brain plasma membranes. Biochem. Pharmacol. 65, 843–856 (2003).
Hering, H., Lin, C. C. & Sheng, M. Lipid rafts in the maintenance of synapses, dendritic spines, and surface AMPA receptor stability. J. Neurosci. 23, 3262–3271 (2003).
Zhuang, L., Kim, J., Adam, R. M., Solomon, K. R. & Freeman, M. R. Cholesterol targeting alters lipid raft composition and cell survival in prostate cancer cells and xenografts. J. Clin. Invest. 115, 959–968 (2005).
Therond, P. P. Release and transportation of Hedgehog molecules. Curr. Opin. Cell Biol. 24, 173–180 (2012).
Vyas, N. et al. Nanoscale organization of hedgehog is essential for long-range signaling. Cell 133, 1214–1227 (2008).
Cooper, M. K., Porter, J. A., Young, K. E. & Beachy, P. A. Teratogen-mediated inhibition of target tissue response to Shh signaling. Science 280, 1603–1607 (1998).
Dierker, T., Dreier, R., Petersen, A., Bordych, C. & Grobe, K. Heparan sulfate-modulated, metalloprotease-mediated sonic hedgehog release from producing cells. J. Biol. Chem. 284, 8013–8022 (2009).
Edison, R. J. & Muenke, M. Central nervous system and limb anomalies in case reports of first-trimester statin exposure. N. Engl. J. Med. 350, 1579–1582 (2004).
Bellosta, S., Paoletti, R. & Corsini, A. Safety of statins: focus on clinical pharmacokinetics and drug interactions. Circulation 109, III50–57 (2004).
Lancaster, M. A. et al. Guided self-organization and cortical plate formation in human brain organoids. Nat. Biotechnol. 35, 659–666 (2017).
Mariani, J. et al. FOXG1-dependent dysregulation of GABA/glutamate neuron differentiation in autism spectrum disorders. Cell 162, 375–390 (2015).
Cobos, I. et al. Mice lacking Dlx1 show subtype-specific loss of interneurons, reduced inhibition and epilepsy. Nat. Neurosci. 8, 1059–1068 (2005).
Fontebasso, A. M. et al. Recurrent somatic mutations in ACVR1 in pediatric midline high-grade astrocytoma. Nat. Genet. 46, 462–466 (2014).
Dimidschstein, J. et al. A viral strategy for targeting and manipulating interneurons across vertebrate species. Nat. Neurosci. 19, 1743–1749 (2016).
Lancaster, M. A. & Knoblich, J. A. Generation of cerebral organoids from human pluripotent stem cells. Nat. Protoc. 9, 2329–2340 (2014).
Buglino, J. A. & Resh, M. D. Hhat is a palmitoylacyltransferase with specificity for N-palmitoylation of Sonic Hedgehog. J. Biol. Chem. 283, 22076–22088 (2008).
Berthiaume, L., Peseckis, S. M. & Resh, M. D. Synthesis and use of iodo-fatty acid analogs. Methods Enzymol. 250, 454–466 (1995).
Alland, L., Peseckis, S. M., Atherton, R. E., Berthiaume, L. & Resh, M. D. Dual myristylation and palmitylation of Src family member p59fyn affects subcellular localization. J. Biol. Chem. 269, 16701–16705 (1994).
Acknowledgements
We would like to thank S. Anderson for providing the LHX6-citrine hPSC line. M. Ross, S. Irion, M. Tomishima and members of the Studer lab for their valuable input on experimental design and feedback on manuscript. This work was supported in part through NYSTEM contract C030137 (L.S.) and through the NIH Cancer Center support grant P30 CA008748. G.C. is supported by a Ruth L. Kirschstein F30 M.D./Ph.D. pre-doctoral fellowship (F30 MH113343–01A1) and a training grant from the National Institute of General Medical Sciences (T32GM007739) to the Weill Cornell/Rockefeller/Sloan-Kettering Tri-Institutional MD-PhD Program.
Author information
Authors and Affiliations
Contributions
G.Y.C.: Conception and study design, Organoid protocol development, hPSC cell line engineering, differentiation and characterization assays and writing of manuscript. L.S.: Conception and study design, data analysis and interpretation, writing of manuscript. J.J.A.: SHH protein analysis. M.D.R.: SHH protein analysis. J.T. SHH protein analysis, hPSC cell line engineering. R.M.W.: Organoid protocol development and analysis. D.C.: cell line engineering.
Corresponding author
Ethics declarations
Competing interests
The Memorial Sloan-Kettering Cancer Center has filed a provisional patent application (US PRO 62/538,350) on the methods described in the manuscript with G. Cederquist and L. Studer listed as inventors. L.S. is a scientific co-founder of Bluerock Therapeutics.
Additional information
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Integrated supplementary information
Supplementary Figure 1 Additional data related to Fig. 1.
(a) Schematic of [I125]Iodopalmitate labeling experiment (left). SHH produced from the iSHH line is palmitoylated at levels proportional to the amount of SHH protein expressed, suggesting that overexpression does not saturate processing machinery. (b) Reproducibility of organizer plating and formation of SHH-H9 spheroids. 1,000 iSHH cells are plated in low-attachment microwells and allowed to aggregate overnight. 10,000 wildtype hPSCs are plated on top of the iSHH organizer cells. (c) Spheroids are embedded in matrigel, and the day of embedding is critical to efficient neuroepithelial growth. SHH organoids (no dox) embedded on day 5 exhibit no neuroepithelial growth (“Failed,” N = 3 organoids), while SHH organoids embedded on day 6 exhibit efficient neuroepithelial formation (–DOX N = 3 organoids; +DOX N = 4 organoids). (d) Typically, the iSHH organizer remains clustered at one pole during differentiation, though in ~ 25% of instances the organizer can split into multiple distinct clusters. Scale bars: 200 μm.
Supplementary Figure 2 Quantification method for characterizing SHH-organoid topography.
(a) SHH-organoids are quantified using a grid of regions of interest (ROIs), and each ROI is associated with an X and Y coordinate. The origin is defined for each section by calculating the “center of mass” of the organizer signal. The grid is then used to define ROIs that are positive for regional markers (e.g. PAX6). The linear distance from all positive ROIs to the origin is calculated, and these data can be plotted as a frequency histogram. (b) Organoids that did not express FOXG1 (7/16 batches), or that (c) had a split organizer (10/40 organoids) were not included in the quantification. Scale bars: 200 μm.
Supplementary Figure 3 Topographic patterning in additional hPSC lines (MEL1, HUES6, HUES8) and iPSC lines (J1 and 348).
(a) The iSHH organizer can induce distinct regional domains that emerge in the anatomically correct topographic order. However, the size of domains and overall growth rate of organoids may differ between lines. Without doxycycline all lines are predominantly PAX6 and FOXG1 positive. Sparse induction of NKX2.1 and NKX2.2 was observed in MEL1 and 348 lines. +Doxycycline, N = 8 organoids, 2 batches for all lines; - Doxycycline, N = 4 organoids, 1 batch for all lines. (b) Pluripotency analysis for 348 iPSC line. Scale bars: 200 μm (a); 100 μm (b).
Supplementary Figure 4 Additional data related to Fig. 2.
(a) iSHH organizer cells (red) at least partially express NKX2.1 (green) and are negative for FOXG1, suggesting hypothalamic identity. N = 8 organoids, 2 batches. (b) SHH-dependent topographic patterning can be achieved without matrigel embedding. N = 8 organoids, 2 batches. (c) MGE-like neuroepithelium (FOXG1+/NKX2.1+) acquires a circular, rosette-like structure suggesting a radial organization. N = 6 organoids, 2 batches. Scale bars: 50 μm (a), 200 μm (b, c).
Supplementary Figure 5 Characterization of maintenance of SHH-organoid topography.
(a) OTX2 and FOXG1 regions remain largely distinct over time, and appear to retain their orientation with respect to the organizer. In some instances, the organizer tissue disperses throughout the organoid, making it difficult to determine orientation. –Dox N = 4 organoids, 1 batch; +Dox N = 8 organoids, 3 batches. (b, c) Cerebral cortex-like tissue consisting of radially organized bands of PAX6, TBR2, and TBR1 emerge in regions distal to the organizer. –Dox N = 4 organoids, 1 batch; +Dox N = 5 organoids, 2 batches. (d) Striatum-like tissue expressing DARPP32 emerges in regions distal to the organizer. LHX6 + cells are found more proximal to the organizer. –Dox N = 4 organoids, 1 batch; +Dox N = 6 organoids, 2 batches. (e, f) Hypothalamic-like cells, which express OTP, POMC, and TH, are found in the immediate vicinity of the organizer. –Dox N = 4 organoids, 1 batch; +Dox N = 3 organoids, 2 batches. Scale bars: 50μm (high magnification), 200μm (low magnification).
Supplementary Figure 6 Characterization of interneuron diversity in SHH-organoids using LHX6-citrine line.
(a) LHX6 + cells emerge in regions proximal to the organizer, and co-express NKX2.1. N = 1 organoid. (b) A subset of LHX6 + cells expresses FOXG1, consistent with striatal or cortical interneuron identity. N = 6 organoids, 2 batches. (c) Some FOXG1+/LHX6 + cells have a leading process morphology, characteristic of migrating cortical interneurons. (d–f) Diverse interneuron populations expressing somatostatin N = 3 organoids, 2 batches (d), parvalbumin N = 3 organoids, 2 batches (e), and calretinin N = 6 organoids, 2 batches (f) are observed. Parvalbumin + cells do not express LHX6, suggesting a non-MGE source of these cells. Scale bars: 50 μm (high magnification), 100 μM (intermediate magnification), 200 μm (low magnification).
Supplementary Figure 7 Additional data related to Fig. 4.
(a) AY9944 and lovastatin treated organoids retain NKX2.1 and OTX2 expression within the organizer at day 20. No Drug N = 12 organoids, 3 batches; Lova N = 11 organoids, 3 batches; AY9944 N = 12 organoids, 3 batches; Cyclopamine N = 8 organoids, 2 batches. (b) Absolute and relative quantification of organizer size in drug treated organoids at day 20. Graphs depict mean ± S.D., dots represent individual organoids. One-way ANOVA with Dunnett Test. **P=0.0038, ****P = 0.0001. No drug N = 14 organoids; Lova N = 13 organoids; AY9944 N = 16 organoids; Cyclopamine N = 14 organoids. All samples from 3 batches. (c) AY9944 strongly inhibits induction of NKX2.2 in day 6 organoids at all concentrations tested. Graph depicts mean ± S.D., dots represent individual organoids. No Drug N = 18 organoids, 3 batches; AY9944 0.31μM N = 14 organoids, 2 batches; AY9944 0.62μM N = 16 organoids, 2 batches; AY9944 1.25μM N = 15 organoids, 2 batches; Lova 2μM, 5μM, 20μM, N = 12 organoids, 2 batches each. (d) Western blot for SHH protein from day 4 hPSC-derived neural differentiations shows appropriate processing of SHH peptide length. Representative image of N = 3 experiments. Scale bars: 100 μM.
Supplementary information
Supplementary Text and Figures
Supplementary Figures 1–7 and Supplementary Tables 1 and 2
Rights and permissions
About this article
Cite this article
Cederquist, G.Y., Asciolla, J.J., Tchieu, J. et al. Specification of positional identity in forebrain organoids. Nat Biotechnol 37, 436–444 (2019). https://doi.org/10.1038/s41587-019-0085-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41587-019-0085-3
This article is cited by
-
Combined small-molecule treatment accelerates maturation of human pluripotent stem cell-derived neurons
Nature Biotechnology (2024)
-
An epigenetic barrier sets the timing of human neuronal maturation
Nature (2024)
-
Induced pluripotent stem cells (iPSCs): molecular mechanisms of induction and applications
Signal Transduction and Targeted Therapy (2024)
-
A beginner’s guide on the use of brain organoids for neuroscientists: a systematic review
Stem Cell Research & Therapy (2023)
-
Temporal morphogen gradient-driven neural induction shapes single expanded neuroepithelium brain organoids with enhanced cortical identity
Nature Communications (2023)