scholarly journals Imaging Three-Dimensional Brain Organoid Architecture from Meso- to Nanoscale across Development

2021 ◽  
Author(s):  
Juan Eduardo Rodriguez-Gatica ◽  
Vira Iefremova ◽  
Liubov Sokhranyaeva ◽  
Si Wah Christina Au Yeung ◽  
Yannik Breitkreuz ◽  
...  

AbstractOrganoids are human stem cell-derived three-dimensional cultures offering a new avenue to model human development and disease. Brain organoids allow studying various aspects of human brain development in the finest details in vitro in a tissue-like context. However, spatial relationships of subcellular structures such as synaptic contacts between distant neurons are hardly accessible by conventional light microscopy. This limitation can be overcome by systems that quickly image the entire organoid in three dimensions and in super-resolution. To that end we have developed a setup combining tissue expansion and light sheet fluorescence microscopy for imaging and quantifying diverse spatial parameters during organoid development. This technique enables zooming from a mesoscopic perspective into super-resolution within a single imaging session, thus revealing cellular and subcellular structural details in three spatial dimensions, including unequivocal delineation of mitotic cleavage planes as well as the alignment of pre- and postsynaptic proteins. We expect light sheet fluorescence expansion microscopy (LSFEM) to facilitate qualitative and quantitative assessment of organoids in developmental and disease-related studies.Summary statementThe combination of light sheet fluorescence and expansion microscopy enables imaging of mature human brain organoids in toto and down to synaptic resolution

2021 ◽  
Author(s):  
Tatsuya Osaki ◽  
Yoshiho Ikeuchi

AbstractMacroscopic axonal connections in the human brain distribute information and neuronal activity across the brain. Although this complexity previously hindered elucidation of functional connectivity mechanisms, brain organoid technologies have recently provided novel avenues to investigate human brain function by constructing small segments of the brain in vitro. Here, we describe the neural activity of human cerebral organoids reciprocally connected by a bundle of axons. Compared to conventional organoids, connected organoids produced significantly more intense and complex oscillatory activity. Optogenetic manipulations revealed that the connected organoids could re-play and recapitulate over time temporal patterns found in external stimuli, indicating that the connected organoids were able to form and retain temporal memories. Our findings suggest that connected organoids may serve as powerful tools for investigating the roles of macroscopic circuits in the human brain – allowing researchers to dissect cellular functions in three-dimensional in vitro nervous system models in unprecedented ways.


2020 ◽  
Vol 14 ◽  
Author(s):  
Takeshi K. Matsui ◽  
Yuichiro Tsuru ◽  
Ken-ichiro Kuwako

Human brain organoids are three-dimensional self-organizing tissues induced from pluripotent cells that recapitulate some aspects of early development and some of the early structure of the human brain in vitro. Brain organoids consist of neural lineage cells, such as neural stem/precursor cells, neurons, astrocytes and oligodendrocytes. Additionally, brain organoids contain fluid-filled ventricle-like structures surrounded by a ventricular/subventricular (VZ/SVZ) zone-like layer of neural stem cells (NSCs). These NSCs give rise to neurons, which form multiple outer layers. Since these structures resemble some aspects of structural arrangements in the developing human brain, organoid technology has attracted great interest in the research fields of human brain development and disease modeling. Developmental brain disorders have been intensely studied through the use of human brain organoids. Relatively early steps in human brain development, such as differentiation and migration, have also been studied. However, research on neural circuit formation with brain organoids has just recently began. In this review, we summarize the current challenges in studying neural circuit formation with organoids and discuss future perspectives.


2021 ◽  
Vol 13 ◽  
Author(s):  
Gabriella Gagliano ◽  
Tyler Nelson ◽  
Nahima Saliba ◽  
Sofía Vargas-Hernández ◽  
Anna-Karin Gustavsson

The function of the neuronal synapse depends on the dynamics and interactions of individual molecules at the nanoscale. With the development of single-molecule super-resolution microscopy over the last decades, researchers now have a powerful and versatile imaging tool for mapping the molecular mechanisms behind the biological function. However, imaging of thicker samples, such as mammalian cells and tissue, in all three dimensions is still challenging due to increased fluorescence background and imaging volumes. The combination of single-molecule imaging with light sheet illumination is an emerging approach that allows for imaging of biological samples with reduced fluorescence background, photobleaching, and photodamage. In this review, we first present a brief overview of light sheet illumination and previous super-resolution techniques used for imaging of neurons and synapses. We then provide an in-depth technical review of the fundamental concepts and the current state of the art in the fields of three-dimensional single-molecule tracking and super-resolution imaging with light sheet illumination. We review how light sheet illumination can improve single-molecule tracking and super-resolution imaging in individual neurons and synapses, and we discuss emerging perspectives and new innovations that have the potential to enable and improve single-molecule imaging in brain tissue.


2019 ◽  
Vol 6 (1) ◽  
pp. 9 ◽  
Author(s):  
Eyal Karzbrun ◽  
Orly Reiner

Brain organoids have recently emerged as a three-dimensional tissue culture platform to study the principles of neurodevelopment and morphogenesis. Importantly, brain organoids can be derived from human stem cells, and thus offer a model system for early human brain development and human specific disorders. However, there are still major differences between the in vitro systems and in vivo development. This is in part due to the challenge of engineering a suitable culture platform that will support proper development. In this review, we discuss the similarities and differences of human brain organoid systems in comparison to embryonic development. We then describe how organoids are used to model neurodevelopmental diseases. Finally, we describe challenges in organoid systems and how to approach these challenges using complementary bioengineering techniques.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yi-Fan Wang ◽  
Cong Liu ◽  
Peng-Fei Xu

AbstractOrganoid has become a novel in vitro model to research human development and relevant disorders in recent years. With many improvements on the culture protocols, current brain organoids could self-organize into a complicated three-dimensional organization that mimics most of the features of the real human brain at the molecular, cellular, and further physiological level. However, lacking positional information, an important characteristic conveyed by gradients of signaling molecules called morphogens, leads to the deficiency of spatiotemporally regulated cell arrangements and cell–cell interactions in the brain organoid development. In this review, we will overview the role of morphogen both in the vertebrate neural development in vivo as well as the brain organoid culture in vitro, the strategies to apply morphogen concentration gradients in the organoid system and future perspectives of the brain organoid technology.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dwaipayan Adhya ◽  
George Chennell ◽  
James A. Crowe ◽  
Eva P. Valencia-Alarcón ◽  
James Seyforth ◽  
...  

Abstract Background The inability to observe relevant biological processes in vivo significantly restricts human neurodevelopmental research. Advances in appropriate in vitro model systems, including patient-specific human brain organoids and human cortical spheroids (hCSs), offer a pragmatic solution to this issue. In particular, hCSs are an accessible method for generating homogenous organoids of dorsal telencephalic fate, which recapitulate key aspects of human corticogenesis, including the formation of neural rosettes—in vitro correlates of the neural tube. These neurogenic niches give rise to neural progenitors that subsequently differentiate into neurons. Studies differentiating induced pluripotent stem cells (hiPSCs) in 2D have linked atypical formation of neural rosettes with neurodevelopmental disorders such as autism spectrum conditions. Thus far, however, conventional methods of tissue preparation in this field limit the ability to image these structures in three-dimensions within intact hCS or other 3D preparations. To overcome this limitation, we have sought to optimise a methodological approach to process hCSs to maximise the utility of a novel Airy-beam light sheet microscope (ALSM) to acquire high resolution volumetric images of internal structures within hCS representative of early developmental time points. Results Conventional approaches to imaging hCS by confocal microscopy were limited in their ability to image effectively into intact spheroids. Conversely, volumetric acquisition by ALSM offered superior imaging through intact, non-clarified, in vitro tissues, in both speed and resolution when compared to conventional confocal imaging systems. Furthermore, optimised immunohistochemistry and optical clearing of hCSs afforded improved imaging at depth. This permitted visualization of the morphology of the inner lumen of neural rosettes. Conclusion We present an optimized methodology that takes advantage of an ALSM system that can rapidly image intact 3D brain organoids at high resolution while retaining a large field of view. This imaging modality can be applied to both non-cleared and cleared in vitro human brain spheroids derived from hiPSCs for precise examination of their internal 3D structures. This process represents a rapid, highly efficient method to examine and quantify in 3D the formation of key structures required for the coordination of neurodevelopmental processes in both health and disease states. We posit that this approach would facilitate investigation of human neurodevelopmental processes in vitro.


The Analyst ◽  
2021 ◽  
Author(s):  
Yucheng Sun ◽  
Seungah Lee ◽  
Seong Ho Kang

The contact distance between mitochondria (Mito) and endoplasmic reticulum (ER) has received considerable attention owing to their crucial function in maintaining lipid and calcium homeostasis. Herein, cubic spline algorithm-based depth-dependent...


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Lillian K Fritz-Laylin ◽  
Megan Riel-Mehan ◽  
Bi-Chang Chen ◽  
Samuel J Lord ◽  
Thomas D Goddard ◽  
...  

Leukocytes and other amoeboid cells change shape as they move, forming highly dynamic, actin-filled pseudopods. Although we understand much about the architecture and dynamics of thin lamellipodia made by slow-moving cells on flat surfaces, conventional light microscopy lacks the spatial and temporal resolution required to track complex pseudopods of cells moving in three dimensions. We therefore employed lattice light sheet microscopy to perform three-dimensional, time-lapse imaging of neutrophil-like HL-60 cells crawling through collagen matrices. To analyze three-dimensional pseudopods we: (i) developed fluorescent probe combinations that distinguish cortical actin from dynamic, pseudopod-forming actin networks, and (ii) adapted molecular visualization tools from structural biology to render and analyze complex cell surfaces. Surprisingly, three-dimensional pseudopods turn out to be composed of thin (<0.75 µm), flat sheets that sometimes interleave to form rosettes. Their laminar nature is not templated by an external surface, but likely reflects a linear arrangement of regulatory molecules. Although we find that Arp2/3-dependent pseudopods are dispensable for three-dimensional locomotion, their elimination dramatically decreases the frequency of cell turning, and pseudopod dynamics increase when cells change direction, highlighting the important role pseudopods play in pathfinding.


2018 ◽  
Vol 45 (3) ◽  
pp. 0307006 ◽  
Author(s):  
谢新林 Xie Xinlin ◽  
陈蓉 Chen Rong ◽  
赵宇轩 Zhao Yuxuan ◽  
费鹏 Fei Peng

2019 ◽  
Vol 25 (3) ◽  
pp. 753-761 ◽  
Author(s):  
Warren Colomb ◽  
Matthew Osmond ◽  
Charles Durfee ◽  
Melissa D. Krebs ◽  
Susanta K. Sarkar

AbstractThe absence of quantitative in vitro cell–extracellular matrix models represents an important bottleneck for basic research and human health. Randomness of cellular distributions provides an opportunity for the development of a quantitative in vitro model. However, quantification of the randomness of random cell distributions is still lacking. In this paper, we have imaged cellular distributions in an alginate matrix using a multiview light sheet microscope and developed quantification metrics of randomness by modeling it as a Poisson process, a process that has constant probability of occurring in space or time. We imaged fluorescently labeled human mesenchymal stem cells embedded in an alginate matrix of thickness greater than 5 mm with $\sim\! {\rm 2}{\rm. 9} \pm {\rm 0}{\rm. 4}\,\mu {\rm m}$ axial resolution, the mean full width at half maximum of the axial intensity profiles of fluorescent particles. Simulated randomness agrees well with the experiments. Quantification of distributions and validation by simulations will enable quantitative study of cell–matrix interactions in tissue models.


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