Generation and Downstream Analysis of Single-Cell and Single-Nuclei Transcriptomes in Brain Organoids

Summary

Here, we introduce a comprehensive protocol for the generation and downstream analysis of human brain organoids using single-cell and single-nucleus RNA sequencing.

Abstract

Over the past decade, single-cell transcriptomics has significantly evolved and become a standard laboratory method for simultaneous analysis of gene expression profiles of individual cells, allowing the capture of cellular diversity. In order to overcome limitations posed by difficult-to-isolate cell types, an alternative approach aiming at recovering single nuclei instead of intact cells can be utilized for sequencing, making transcriptome profiling of individual cells universally applicable. These techniques have become a cornerstone in the study of brain organoids, establishing them as models of the developing human brain. Leveraging the potential of single-cell and single-nucleus transcriptomics in brain organoid research, this protocol presents a step-by-step guide encompassing key procedures such as organoid dissociation, single-cell or nuclei isolation, library preparation and sequencing. By implementing these alternative approaches, researchers can obtain high-quality datasets, enabling the identification of neuronal and non-neuronal cell types, gene expression profiles, and cell lineage trajectories. This facilitates comprehensive investigations into cellular processes and molecular mechanisms shaping brain development.

Introduction

Over the last years, organoid technologies have emerged as a promising tool to culture organ-like tissues^1,2,3. Especially for organs that cannot be easily accessed, such as the human brain, organoids offer the opportunity to gain insights into development and disease manifestation⁴. As such, brain organoids have been widely used as an experimental model to investigate various human brain disorders, including developmental, psychiatric, or even neurodegenerative diseases^4,5,

Protocol

The described protocol is performed in a biosafety level 1 laboratory of the Max Delbrück Center for Molecular Medicine (approval number: 138/08), in accordance with the requirements and in compliance with EU and national rules on ethics in research.

1. Derivation of forebrain organoids from induced pluripotent stem cells (iPSCs)

NOTE: This protocol was tested for several different iPSC lines cultured in a variety of stem cell media from differen.......

Discussion

Transcriptomic analysis of single cells and single nuclei has emerged as a pivotal tool for understanding gene regulatory mechanisms within complex tissues. Both methods enable transcriptome studies of brain organoids. To ensure an overall successful experiment, the quality of the starting material is of high relevance. Therefore, it is necessary to cut the organoids regularly to prevent the formation of a necrotic core²⁶. It is also possible to eliminate this issue with an Air-Liquid Interface cu.......

Materials

Name	Company	Catalog Number	Comments
1,4-DITHIO-DL-THREIT-LSG., F. D. MOL.-BIOL., ~1 M IN H2O (DTT)	Sigma	43816-10ML
1.5 ml DNA low binding tubes	VWR	525-0130	microcentrifuge tube
10x Cellranger pipeline			analysis pipline
15 ml Falcon	Falcon		Centrifuge tube
2-Mercaptoethanol (BME)	Life Technologies	21985023
50 ml Falcon	Falcon		Centrifuge tube
A83-01	Bio Technologies	379762
Antibiotic/Antimycotic Solution (100X)	Life Technologies	15240062
B-27 Plus Supplement	Life Technologies	17504044
B-27 Supplement without vitamin A	Life Technologies	12587010
Bovine serum albumin, fatty acid free (BSA)	Sigma Aldrich	A8806-5G
cAMP	Biogems	6099240
cAMP	Biogems	6099240
C-CHIP NEUBAUER IMPROVED	VWR	DHC-N01
Cell strainer 40 µm	Neolab	352340
Cell strainer 70 µm (white) Nylon	Sigma	CLS431751-50EA
Chromium Controller & Next GEM Accessory Kit	10X Genomics	1000204
Chromium Next GEM Chip G Single Cell Kit, 16 rxns	10X Genomics	1000127
Chromium Next GEM Single Cell 3' Kit v3.1	10X Genomics	1000268
Complete,  EDTA-free Protease Inhibitor Cocktaill	Roche	11873580001
DAPI	MERCK Chemicals	0000001722
DMEM/F12	Life Technologies	11320074
Dounce tissue grinder set 2 mL complete	Sigma Aldrich	10536355
Essential E8 Flex Medium	Life Technologies	A2858501
EVE Cell Counting Slides	VWR	EVS-050 ( 734-2676)
Foetal bovine serum tetracycline free (FBS)	PAN Biotech	P30-3602
Geltrex LDEV-Free (coating)	Life Technologies	A1413302
gentleMACS	Miltenyi Biotec		dissociation maschine
GlutaMAX supplements	Life Technologies	35050038
Heparin sodium cell culture tested	Sigma	H3149-10KU
human recombinant BDNF	StemCell Technologies	78005.3
human recombinant GDNF	StemCell Technologies	78058.3
Insulin Solution Human	Sigma Aldrich	I2643-25MG
Knockout serum replacement	Life Technologies	10828028
LDN193189 Hydrochloride 98%	Sigma Aldrich	130-106-540
MEM non-essential amino acid (100x)	Sigma Aldrich	M7145-100ml
MgCl2 Magnesium Chloride (1M) RNAse free	Thermo Scientific	AM9530G
mTeSR Plus	StemCell Technologies	100-0276	stem cell medium
mTeSR1	StemCell Technologies	85850	stem cell medium
N2 Supplement	StemCell Technologies	17502048
Neural Tissue Dissociation Kit	Miltenyi Biotec B.V. & Co. KG	130-092-628
Neurobasal Plus	Life Technologies	A3582901
NextSeq500 system	Illumina		Sequencer
NP-40 Surfact-Amps Detergent Solution	Life Technologies	28324
PBS Dulbecco’s	Invitrogen	14190169
PenStrep (Penicillin - Streptomycin)	Life Technologies	15140122
Percoll	Th. Geyer	10668276
Pluronic (R) F-127	Sigma Aldrich	P2443-1KG
RiboLock RNase Inhibitor	Life Technologies	EO0382
Rock Inhibitor (Y-27632 dihydrochloride) SB	Biomol	Cay10005583-10
SB 431542	Biogems	3014193
Sodium chloride NaCl (5M), RNase-free-100 mL	Invitrogen	AM9760G
StemFlex Medium	Thermo Scientific	A3349401	stem cell medium
StemMACS iPS-Brew XF	Miltenyi Biotec	130-104-368	stem cell medium
TC-Platte 96 Well, round bottom	Sarstedt	83.3925.500
TISSUi006-A	TissUse GmbH	https://hpscreg.eu/cell-line/TISSUi006-A
Trypan Blue	T8154-20ml	Sigma
TrypLE Express Enzyme, no phenol red	Life Technologies	12604013	Trypsin-based reagent
UltraPure 1M Tris-HCl Buffer, pH 7.5	Life Technologies	15567027
XAV939	Enzo Life sciences	BML-WN100-0005