After graduating from Hangzhou Foreign Language School Hang Yang studied undergrad and doctoral degree at the University of Toronto, Canada. At the age of 29, he published a paper on Cell Stem Cell, and served as a co-communication worker.
Figure | Yang Donghe (Source: Yang Donghe)
It is reported that this study has established a comprehensive multi-lineage development map of human embryonic heart for the first time, providing a variety of methods for differentiation of embryonic heart cells in vitro. It is also shown that the process of studying the development of the multi-lineage heart region of human embryonic stem cell differentiation technology and single-cell transcriptome sequencing technology is combined. These findings have the possibility of clinical application, such as those used to study congenital heart disease and chamber-specific cardiomyopathy, as well as to develop novel cell therapies.
Specifically: First, based on this study, a cardiac organoid model of multi-cell types and multi-chamber can be used to simulate developmental processes and disease occurrence. In this study, the differentiation methods of most cardiomyocyte species have been explained. Then, after establishing organoid models, they can be used to conduct electrophysiological research, gene regulation research, and disease models.
Second, differentiated left ventricular cardiomyocytes can be used to treat myocardial infarction. The specific strategy is to transplant the mature left ventricular cells into the myocardial infarction model after biochemical and metabolic maturation of left ventricular cells to promote therapeutic effects.
(Source: Cell Stem Cell)
Embryonic multi-lineage heart region development, which is of great significance to the study of cardiovascular diseases
Previous studies have shown that the heart of mammalians contains a variety of functionally specific cardiomyocytes, which can be roughly classified as working cells with contraction function and self-regulatory cells with automatic rhythmicity.
According to mouse embryo lineage tracking and retrospective analysis, it was found that cardiomyocytes in different regions and with specific functions developed from different core regions. These different heart areas can be roughly classified as the first heart area, the first second heart area and the second heart area.
Previous studies have shown that in embryonic development, these different heart region cells present different anatomical and gene expression characteristics.
For example, in the early embryonic stage of mice, the first-born heart region cells are located on the ventral side of the crescent body of the heart, and highly express genes such as Hand1, Tbx5 and Hcn4. The second heart-generating cell is located on the dorsal side of the first heart-generating cell and highly expresses genes such as Isl1, Hoxa1, Hoxb1, Tbx1 and Fgf10.
As the embryo develops, the first heart region mainly develops into left ventricular cardiomyocytes and atrioventricular cardiomyocytes; the first second heart region develops into right ventricular cardiomyocytes and outflow tract cardiomyocytes; the latter second heart region produces atrial cardiomyocytes and sinus venous derived structures.
In recent years, studies on early mouse gastrulation have shown that when gastrulation is formed, precursors of these different core lineages have been produced. Therefore, the development of embryonic multi-lineage heart zones is of great significance to the study of heart development and cardiovascular diseases.
Previous studies have shown that cardiomyocyte subtypes originating from different heart regions are affected by multiple chamber-specific cardiovascular diseases. For example, arrhythmic right ventricular cardiomyopathy, left heart arrhythmia syndrome and various valve diseases mostly occur in specific chambers and cardiomyocytes.
Therefore, in order to better study these heart diseases with cell-source specificity and develop effective therapies, it is very necessary to develop in vitro systems to accurately study the development of each cell subtype.
To a certain extent, the animal model provides this study with a model to study the development of the heart region.However, due to the lack of early human fetal tissue, the academic community knows little about the development of human heart zone.
Although there have been studies that from human embryonic stem cells , structures similar to the first and second heart regions can be differentiated in vitro. However, the comprehensive multi-linear, multi-developmental stage development map of human heart region has not been described.
Therefore, in order to use human pluripotent stem cells to simulate the lineage development of the first, second and second heart regions of multi-stage human embryos, the team first analyzed the single-cell transcriptome of mouse mesoderm cells. After
analysis, two important signaling pathways, BMP and Nodal signaling pathways, were found, which were specifically expressed in the first and second heart regions of mice. By manipulating these two signaling pathways, the research team differentiated from human embryonic stem cells into the first heart region, the first second heart region and the second heart region of the post-second heart region, and then used single-cell sequencing to describe their transcriptome in detail.
Based on these single-cell transcriptome data, the researchers combined the single-cell sequencing data of human gastrulation phase to elaborate the following rules for the first time: the mesoderm subtypes of the heart region differentiated by stem cells have different temporalities, which is consistent with recent mouse retrospective studies. After
, it differentiated daughter cells from these different cardiac mesoderm cells, and for the first time the human multicentric region, multi-developmental stage transcription submap was drawn through single-cell sequencing.
(Source: Cell Stem Cell)
By analyzing the single-cell transcriptome of daughter cells, the research team found that BMP and retinoic acid (RA) signaling act on daughter cells of different lineages.
specifically: the first heart zone is not regulated by RA, the second heart zone is regulated by RA, and the first second heart zone is regulated by these two signal paths at the same time. After understanding the signaling pathways of daughter cells, by manipulating specific signaling pathways in stages, the researchers finally differentiated the subtypes of cardiomyocytes that express key molecules and electrophysiological characteristics from different daughter cell subtypes.
Finally, the team used machine learning and integrated analysis technology to compare the differentiated myocardial subtypes in vitro, their corresponding mice, and human cell transcriptomes. The results showed that the subtype of cardiomyocyte population differentiated from multifunctional stem cells is highly similar to the cells in these animals.
Recently, a related paper was published on Cell Stem Cell (IF 24.6). Yang Donghe served as a member and co-communication, and Gordon M. Keller, professor of the Department of Medical Biological Physics at the University of Toronto, serves as the corresponding author of co- .
Figure | Related papers (Source: Cell Stem Cell)
review experts pointed out that researchers found key signaling pathways from the occurrence of mouse germ layer lineages and successfully applied these findings to the human embryonic stem cell system.
This work provides detailed data and detailed cross-species comparisons to understand the establishment of mammalian heart lineages and the fate regulation mechanism of pluripotent stem cells. is an important supplement to mammalian heart lineage development theory and will promote the development of early cardiac embryonic development and stem cell regenerative medicine related fields.
At the same time, cross-species analysis in the study, as well as comparative analysis of in vivo and in vitro cells, will also provide new ideas and research objects for heart area research.
In the field of stem cells, the first time it was reported to establish embryonic stem cells to differentiate right ventricular cells
According to reports, for this project establishment stage is more difficult. The team initially believed that differentiation of all cardiac lineages from human embryonic stem cells was a big problem, and even if differentiation of different cardiac mother cells was not sure whether they could differentiate into different types of cardiac myocardial cell subspecies in vitro.
various uncertainties and the lack of scientific research funds for this project have led to relatively bumpy project establishment in the first year. However, the research team still believes that the project is of great significance to development. If the project is successful, it can prove the possibility of studying high-precision embryo development in vitro.
In the project establishment stage, the researchers summarized multiple retrospective studies of mice in recent years and reanalysed the latest single-cell sequencing data in the embryonic intestinal stage of mice, thereby determining the gene expression maps of each heart region mother cell subspecies and several important specifically expressed signaling pathways.
The first important breakthrough in this stage was the discovery of the TGF-beta signaling pathway in mouse data specifically expressed in mother cells in different heart regions, which allowed them to successfully differentiate mesoderm cells from human embryonic stem cells, thus giving them some confidence in this topic. After
, the team summarized experimental data and bioinformatic analysis results, correlated myocardial subtypes developed from different heart regions with different types of heart disease, and finally received funding from Canadian Institute of Health Research and cell therapy company Bluerock Therapeutics. After obtaining scientific research funds, the researchers first performed single-cell sequencing of different heart zone mesoderm cells, thereby confirming the existence of the first heart zone, the first second heart zone and the second heart zone mesoderm subtype.
uses stem cells to simulate embryonic development in vitro, which has the huge advantage that cells can be independently differentiated and the desired cell type can be isolated and purified, so as to conduct more in-depth research.
Then, through transcriptome analysis technology, the research team successively determined the highly expressed cell membrane proteins in each heart region's mesoderm subtype. In addition, it also uses flow technology to separate and separate the core lineages in order to study the independent differentiation and development of each lineage. After the isolated heart zone mother cells were found, the research began to go smoothly. Consistent with the team's conjecture, each purified heart zone mother cell will differentiate into different daughter cells. By analyzing the transcriptome of daughter cells, it further confirmed that these human embryonic stem cells induced cardiac subcellular cells express similar genes to those in mouse embryos.
When analyzing heart cells in a deeper manner, Yang Donghe, who was the first student, found that the former second cardiac region subcellular cells highly expressed genes acting on Bmp signaling pathway, which is consistent with the study of the former second cardiac region in mice in recent years.
According to this discovery, he used some experiments to inhibit or enhance the role of this signal pathway in the previous second heart region. Finally, it was found that strengthening this signaling pathway could allow the anterior second heart region to roughly differentiate into right ventricular cardiomyocytes.
It said: "In the field of stem cells, we reported the first successful method of establishing embryonic stem cells to differentiate right ventricular cells. Using a similar method, we differentiated other myocardial subtypes from other heart zone subtypes. Later, we also analyzed all the transcription groups of myocardial subtypes differentiated from human embryonic stem cells and compared them with mouse cardiomyocytes and human cardiomyocytes, thus drawing the following conclusion: cells differentiated in vitro are roughly the same as those developed in vivo."
"forced" from bioinformatics analysis
What made Yang Donghe more memorable is that it was the differences between his colleagues on the understanding of the topic at the beginning of the project, as well as the experience of overcoming experimental problems and self-biological information analysis during the epidemic. html When l2
first started the project, a relatively senior colleague thought that Yang Donghe's experimental vision might be difficult to achieve. However, he insisted on his own thinking, that is, to find important signal pathways from high-throughput sequencing , so as to simulate the development of the heart in vitro.
Yang Donghe said: "This experience made me realize that doing scientific research requires a certain amount of confidence and persistence in my own ideas. With strong theoretical support, some radical cutting-edge projects can be done. "
The second unforgettable experience is that the topic was affected by emergencies during the epidemic. In his Ph.D. 2-3 In the grade, the outbreak of the North American epidemic directly affected the progress of the experiment. At the same time, the collaborators who helped them analyze bioinformatics went to other countries after graduation, which led to a partial interruption of the bioinformatic analysis of the project. Under heavy pressure, Yang Donghe began to analyze bioinformatics from students during the epidemic isolation period and finally completed the study.
For the future, Yang Donghe said that the first is to combine myocardial subspecies differentiation methods and induce pluripotent stem cell to study different heart diseases. The second is to establish a multi-lineage heart region epigenetic map, and then combine the existing transcriptome data to further study the molecular basis of heart region differentiation. in career planning, he said: "I will go to the United States for post-blog research soon, hoping to have the opportunity to cooperate with domestic research groups. ”
Reference materials:
1.Yang, D., Gomez-Garcia, J., Funakoshi, S., Tran, T., Fernandes, I., Bader, G. D., ... & Keller, G. M. (2022). Modeling human multi-lineage heart field development with pluripotent stem cells. Cell Stem Cell, 29(9), 1382-1401.
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