A protein complex primarily recognized for its role in maintaining the structural integrity of tissues has been discovered to perform a surprising second job: acting as a cleanup crew for the body. New research reveals that E-cadherin, a protein essential for keeping epithelial cells connected in sealed layers, is instrumental in helping these cells engulf and dispose of neighboring dead cells.<\/p>\n
The discovery, published in the journal Nature Communications<\/em>, offers significant new insights into the complex mechanics of tissue maintenance and the potential origins of chronic inflammation. By identifying how tissues efficiently clear out cellular debris\u2014the remnants of dying cells that often trigger inflammatory responses\u2014researchers may have uncovered a critical mechanism that, when it fails, could lead to a range of chronic health conditions.<\/p>\n Epithelial cells form the protective, continuous layers that line our skin, gut, airways, and various internal organs. To maintain these vital barriers, cells rely on the E-cadherin complex, a molecular system that acts as a form of "cellular glue." By linking neighboring cells together, E-cadherin provides the structural strength required for these tissues to remain intact and perform their physiological duties.<\/p>\n A research team led by Verena Ruprecht, an ICREA Research Professor, sought to understand how these tissues manage the inevitable presence of dying cells. Working with living zebrafish and mouse embryos\u2014models that allow for high-resolution, real-time imaging\u2014the team observed that the same molecular machinery responsible for cell-to-cell adhesion also congregates at the precise point where a dying cell makes contact with the surrounding healthy tissue.<\/p>\n This observation led the researchers to test whether E-cadherin and its associated proteins were attaching to the dying cell in the same manner they would attach to a neighboring epithelial cell. In a series of ingenious experiments, the team challenged the tissue. First, they introduced dying cells that had been intentionally stripped of E-cadherin; the epithelial tissue successfully engulfed these cells just as it would have with normal, intact dying cells. <\/p>\n Taking the inquiry a step further, the researchers introduced fat droplets that lacked any proteins but carried a specific "eat-me" signal typically found on the surface of dying cells. The epithelial cells engulfed these synthetic droplets with equal efficiency. <\/p>\n "We were intrigued to find out that epithelial cells repurpose their molecular adhesion machinery\u2014the ‘glue’ that normally holds them together\u2014to engulf dying cells," says Professor Ruprecht, the senior author of the study. This indicates that the machinery is not merely reactive to specific protein signatures on the dying cell, but is instead an adaptive system capable of being redirected toward clearance.<\/p>\n Engulfing a target roughly the same size as the cell itself poses a formidable mechanical challenge. Epithelial cells must remain tightly packed to maintain a seal, yet they must also possess the flexibility to reshape themselves to accommodate the engulfment process without compromising the integrity of the tissue barrier.<\/p>\n Using advanced live-imaging techniques, the researchers mapped the process of engulfment. They discovered that the epithelial cells exhibit a remarkable form of functional polarity: the upper and lower surfaces of a single cell act in different ways. While the lower surface undergoes significant deformation, stretching and bending around the dying cell to draw it inside, the upper surface\u2014which is often exposed to the external environment or a lumen\u2014remains strikingly steady.<\/p>\n Measurements taken throughout the process confirmed that the upper surface area changed very little, ensuring that the barrier remained closed and protected. Professor Ruprecht compares this coordinated effort to a line of dancers performing a synchronized routine. "Their upper bodies remain steady while their feet perform increasingly complicated movements when a dying cell appears," she explains. "It’s the same dancer with a different choreography."<\/p>\n To understand the mechanical underpinnings of this cleanup process, the research team delved into the specific components of the E-cadherin complex. They identified two key roles played by proteins within this assembly: a "rope" and a "brake."<\/p>\n One protein component acts much like a tether or rope, connecting the molecular assembly to the cell\u2019s internal cytoskeleton. This connection is vital, as it allows the cell to transmit the physical force necessary to pull the dying cell into its interior. When researchers engineered cells that lacked this tethering protein, or specifically removed the region of the protein that attaches to the skeleton, the cells lost the ability to swallow the dead material entirely.<\/p>\n The second component acts as a brake on the cell\u2019s contractile machinery. Interestingly, the researchers found that removing this "brake" did not accelerate the process. Instead, it had a counterintuitive effect: the cell became overly stiff, losing the essential plasticity required to move around and consume the dying cell. This finding highlights the delicate balance of forces required for successful cellular clearance; the process is not simply about exerting maximum force, but about regulating that force with precision.<\/p>\n To determine if this process is a universal biological feature, the team expanded their study to include mouse embryos. By blocking E-cadherin in these models, they observed that dying cells were left to accumulate, failing to be cleared by the surrounding tissue. This result mirrored the findings in zebrafish, providing strong evidence that the mechanism is conserved across vertebrate evolution.<\/p>\n This work builds upon earlier research by Professor Ruprecht, which demonstrated that embryos use epithelial tissues to cooperatively remove dying cells as a form of early innate immune defense. Because embryos are transparent, they provide a unique window into these events, allowing scientists to observe cellular behavior at a level of detail that remains currently impossible within the complex, opaque environment of an adult human body.<\/p>\n A lingering question for the scientific community is whether this E-cadherin-dependent mechanism continues to function in adult organisms, including humans. While the researchers have yet to confirm this, there is compelling evidence to suggest it might.<\/p>\n In adult humans and other mammals, epithelial tissues are known to perform consistent clearance of dying cells in regions such as the retina, the colon, the airways, and the mammary gland. Furthermore, E-cadherin is ubiquitous throughout the body\u2019s epithelial tissues, and its structural composition has remained remarkably stable throughout evolution. These factors make it a prime candidate for a broadly utilized, ancient cleanup mechanism that serves to protect tissues from the damage caused by lingering debris.<\/p>\n The implications for human health are substantial. When dead cells are not efficiently removed, they eventually rupture, spilling their internal contents into the surrounding tissue. This release can provoke chronic inflammation, a condition linked to a wide array of diseases, ranging from autoimmune disorders to cancer and cardiovascular disease. <\/p>\n The findings emphasize that efficient tissue cleanup is not just about identifying the right chemical signals. It is a physical, structural feat that requires cells to undergo dramatic, controlled deformation while maintaining the integrity of the body\u2019s vital barriers. "Studying the mechanisms of how dying cells can be removed efficiently from tissues is of very high relevance to human health," concludes Professor Ruprecht.<\/p>\n The research was led by joint first authors Hanna-Maria H\u00e4kkinen, Marta Batet Palau, and Laura F. Bianchi, and supervised by Professor Ruprecht. The study received funding from the Spanish Ministry of Science and Innovation, the Human Frontier Science Program, the European Union’s Horizon Europe program, and the "la Caixa" Foundation, with additional support from the European Social Fund. The project utilized the advanced core facilities for light microscopy, tissue engineering, and protein technologies at the Centre for Genomic Regulation (CRG). As this research continues to develop, it may open new avenues for therapeutic interventions that bolster the body’s natural, yet complex, ability to maintain tissue health from within.<\/p>\n","protected":false},"excerpt":{"rendered":" A protein complex primarily recognized for its role in maintaining the structural integrity of tissues has been discovered to perform a surprising second job: acting as a cleanup crew for the body. New research reveals that E-cadherin, a protein essential for keeping epithelial cells connected in sealed layers, is instrumental in helping these cells engulf […]<\/p>\n","protected":false},"author":1,"featured_media":2268,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[370],"tags":[2024,1161,4163,60,4162,61,441,1647,371,372,1460],"class_list":["post-2269","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science-and-nature","tag-biological","tag-cellular","tag-cleanup","tag-found","tag-glue","tag-nature","tag-play","tag-role","tag-science","tag-space","tag-unexpected"],"_links":{"self":[{"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/posts\/2269","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2269"}],"version-history":[{"count":0,"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/posts\/2269\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/media\/2268"}],"wp:attachment":[{"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2269"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2269"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Cellular Glue Takes on a Cleanup Role<\/h3>\n
How Cells Eat Without Breaking the Barrier<\/h3>\n
A Molecular Rope and Brake<\/h3>\n
The Same Mechanism Appears in Mammals<\/h3>\n
Could the Same Process Work in Adult Tissues?<\/h3>\n