In Simple Terms
Scientists have figured out how to grow tiny clusters of human brain cells in a lab. These clusters develop in ways similar to a real human brain, helping researchers understand brain development and study brain diseases better.
Introduction
In a groundbreaking study, researchers from Harvard University and the Broad Institute have successfully grown small clusters of human brain cells, known as cortical organoids, in the lab. These organoids have been cultivated from human pluripotent stem cells and have continued to grow over five years, offering a new perspective on brain development and disease.
What Are Cortical Organoids?
Cortical organoids are miniature models of brain cells, but they are not complete brains. They start from pluripotent stem cells that are chemically guided to become cortical cells. Each organoid contains over a million cells, including neurons and glial cells, which are crucial for brain development. Although they lack sensory input and connection to a body, these organoids serve as vital models for studying brain growth.
Growth Timeline
The researchers tracked the development of these organoids over several years, analyzing 424,720 individual cells across 110 organoids at different time points. The findings revealed that the gene activity patterns in the organoids change over time, mimicking the development of the human brain from prenatal stages to postnatal periods. However, this doesn’t mean an organoid at one year is equivalent to a one-year-old child’s brain; it indicates that the cells start acquiring postnatal characteristics.
Genetic Markers and Age Indicators
In addition to gene activity analysis, the researchers measured chemical changes in DNA, such as methylation, which vary with age. They identified 213 genomic sites showing age-related changes in the organoids, demonstrating how “genetic clocks” can estimate the biological age of cells.
Challenges and Conclusions
While the study shows that organoids can follow a developmental timeline similar to the human brain, it also highlights significant challenges. Culturing these cells is time-consuming and costly, with complex techniques involved. Although these studies don’t guarantee precise recreation of neurological disorders in the lab, they provide a foundation for exploring how genetic factors influence brain development.
Conclusion
Research on cortical organoids reveals the potential of human brain cells to grow and develop in a lab setting, opening new avenues for studying brain development and related diseases. These studies offer a deeper understanding of how neurons function and interact with their environment, contributing to the development of new treatments for neurological disorders.