Earliest signs of an immune response found in developing embryos

February 10, 2021

Researchers at the Centre for Genomic Regulation (CRG) reveal that newly formed embryos clear dying cells to maximise their chances of survival. It is the earliest display of an innate immune response found in vertebrate animals to date.

The findings, which are published today in the journal Nature, may aid future efforts to understand why some embryos fail to form in the earliest stages of development, and lead to new clinical efforts in treating infertility or early miscarriages.

An embryo is fragile in the first hours after its formation. Rapid cell division and environmental stress make them prone to cellular errors, which in turn cause the sporadic death of embryonic stem cells. This is assumed to be one of the major causes of embryonic developmental failure before implantation.

Living organisms can remove cellular errors using immune cells which are dedicated to carry out this function, but a newly-formed embryo cannot create these specialised cells. To find out whether embryos can remove dying cells before the formation of an immune system, the researchers used high resolution time-lapse imaging technology to monitor zebrafish and mouse embryos, two established scientific models used to study vertebrate development.

They found that epithelial cells - which collectively form the first tissue on the surface of an embryo - can recognise, ingest and destroy defective cells. It is the first time this biological process, known as epithelial phagocytosis, has been shown to clear cellular errors in newly formed vertebrate embryos.

"Long before the formation of the organs, one of the first tasks performed by a developing embryo is to create a protective tissue," says Dr. Esteban Hoijman, first and co-corresponding author of the paper.

According to Dr. Hoijman, epithelial phagocytosis was a surprisingly efficient process thanks to the presence of arm-like protrusions on the surface of epithelial cells. "The cells cooperate mechanically; like people distributing food around the dining table before tucking into their meal, we found that epithelial cells push defective cells towards other epithelial cells, speeding up the removal of dying cells," he adds.

"Here we propose a new evolutionarily conserved function for epithelia as efficient scavengers of dying cells in the earliest stages of vertebrate embryogenesis," says Dr. Verena Ruprecht, group Leader in the Cell & Developmental Biology program at the CRG and senior author of the paper. "Our work may have important clinical applications by one day leading to improved screening methods and embryo quality assessment standards used in fertility clinics."

According to the authors, the discovery that embryos exhibit an immune response earlier than previously thought warrants further exploration on the role of mechanical cooperation as a physiological tissue function, which remains poorly understood, in other important biological processes such as homeostasis and tissue inflammation.
-end-
The study is published today in the journal Nature. The team was led by the CRG in Barcelona in collaboration with the Pompeu Fabra University (UPF) and the Institute of Photonic Sciences (ICFO), as well as the University Paris-Diderot.

Center for Genomic Regulation

Related Epithelial Cells Articles from Brightsurf:

New way to target some rapidly dividing cancer cells, leaving healthy cells unharmed
Scientists at Johns Hopkins Medicine and the University of Oxford say they have found a new way to kill some multiplying human breast cancer cells by selectively attacking the core of their cell division machinery.

Moffitt researchers identify protein that causes epithelial cancers to spread
In a new article published in the July issue of Cancer Research, Elsa Flores, Ph.D., and her team discovered a key protein that oscillates its expression through microRNA regulation to facilitate cancer spread to distant organs.

Epithelial GPS: Position of RNAi machinery is associated with epithelial identity
Researchers at the Medical University of South Carolina show in a new report that the RNA interference machinery, normally thought to reside in the nucleus or cytoplasm, predominantly localizes to these apical junctions and influences cell biology in the colon.

Nutrient deficiency in tumor cells attracts cells that suppress the immune system
A study led by IDIBELL researchers and published this week in the American journal PNAS shows that, by depriving tumor cells of glucose, they release a large number of signaling molecules.

Scientists modify CAR-T cells to target multiple sites on leukemia cells
In a preclinical study, scientists engineer new CAR-T cells to attack three sites on leukemia cells, instead of one.

Size matters: How cells pack in epithelial tissues
Small-cell clones in proliferating epithelia -- tissues that line all body surfaces -- organize very differently than their normal-sized counterparts, according to a recent study from the Stowers Institute for Medical Research.

Closing the gap -- a two-tier mechanism for epithelial barrier
Scientists from Japan's National Institute for Physiological Sciences and their collaborators report in a new study published in The Journal of Cell Biology that epithelial barrier is composed of two molecular systems with distinct barrier properties.

Dead cells disrupt how immune cells respond to wounds and patrol for infection
Immune cells prioritise the clearance of dead cells overriding their normal migration to sites of injury.

Revealed: How the 'Iron Man' of immune cells helps T cells fight infection
The immune system's killer T cells are crucial in fighting viral infections.

White blood cells related to allergies may also be harnessed to destroy cancer cells
A new Tel Aviv University study finds that white blood cells which are responsible for chronic asthma and modern allergies may be used to eliminate malignant colon cancer cells.

Read More: Epithelial Cells News and Epithelial Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.