In a significant advancement for sensory biology, researchers at the Tufts University School of Medicine and the Graduate School of Biomedical Sciences (GSBS) have unlocked new insights into how the human nose maintains its sense of smell. By developing an innovative, three-dimensional model to observe nerve tissue regeneration, the team has overturned long-held assumptions regarding the role of certain stem cells. Their findings suggest that a specific type of stem cell, previously dismissed by many in the scientific community as largely dormant, is actually a vital engine in the preservation and repair of olfactory neurons.<\/p>\n
Unlike the central nervous system, which possesses a notoriously limited capacity for self-repair, the sensory neurons residing in the nasal cavity demonstrate a remarkable, lifelong ability to regenerate. This continuous renewal process is essential, as these cells are frequently exposed to the harsh, unpredictable conditions of the outside world. However, this delicate biological process is not invincible. The onset of viral infections\u2014most notably COVID-19\u2014prolonged exposure to environmental toxins, or the natural progression of aging can severely diminish the function of these cells or impair their ability to replicate. When these regenerative mechanisms falter, the result is often a partial or complete loss of smell, a condition that can profoundly impact a patient\u2019s quality of life, nutritional intake, and psychological well-being.<\/p>\n
To better understand the complexities of this regenerative failure, the Tufts research team, led by senior author Brian Lin, a research assistant professor in the Department of Developmental, Molecular and Chemical Biology, devised a new, three-dimensional olfactory tissue mouse model. This organoid system serves as a sophisticated, accessible platform for scientists to investigate the cellular dialogue that governs the birth of new neurons. Their study, which was recently published in the journal Cell Reports Methods<\/em>, provides a granular look at the symbiotic relationship between two specific types of stem cells: horizontal basal cells (HBCs) and globose basal cells (GBCs).<\/p>\n The research highlights a sophisticated level of interdependence between these cell populations. According to Lin, the scientific community had historically characterized HBCs as being largely quiescent or dormant, waiting in reserve for catastrophic injury. However, the data collected from the new 3D model tells a different story. "Our research suggests that these two stem cells may be interdependent," Lin explains. "One type that we thought was largely dormant\u2014HBCs\u2014may actually play a crucial role in supporting the production of new neurons and the repair of damaged tissue."<\/p>\n Through the use of the 3D organoid, the team identified a specific subpopulation of HBCs, distinguished by their production of the protein KRT5, which acts as a proactive facilitator in the generation of new olfactory neurons. By selectively depleting these KRT5-expressing cells from the organoid cultures, the researchers observed a significant impairment in the creation of new nerve tissue. This evidence solidifies the role of HBCs as essential, active participants in the regenerative process rather than mere bystanders.<\/p>\n The team also utilized the model to explore the biological reality of aging. By comparing olfactory cells harvested from mice of varying ages, the researchers were able to witness the gradual decline in regenerative capacity in real-time. "We found a decline in the ability of the older mice cells to generate new neurons," says Lin. "We think this is due to a decrease in the GBC population as we age, but we need to do more work to test this hypothesis and, if so, develop ways to rejuvenate them."<\/p>\n A primary objective of this project was to ensure that the scientific insights gained were accessible to a wide range of laboratories, particularly those operating under constraints of limited funding or specialized equipment. The lead author of the study, Juliana Gutschow Gameiro, who conducted this work while a visiting Ph.D. student at GSBS from the State University of Londrina in Brazil, was instrumental in this effort. Under Lin\u2019s guidance, she focused on creating a methodology that could be easily replicated by researchers worldwide.<\/p>\n The urgency for such a tool has never been greater. The COVID-19 pandemic brought the loss of smell to the forefront of global public health concerns, and the condition remains a hallmark of other chronic illnesses, such as Parkinson\u2019s disease. Consequently, a growing number of researchers from diverse fields\u2014many of whom are not specialists in stem cell biology\u2014have turned their attention to the study of olfactory epithelial cells. <\/p>\n "We wanted to develop an easy-to-use model so that non-stem cell biologists and those working in labs with limited resources could use it to better understand how olfactory neurons regenerate and what happens that causes that process to diminish or fail completely," Lin says. By democratizing the tools of discovery, the Tufts team hopes to accelerate the pace of research into olfactory dysfunction, allowing labs across the globe to contribute to the growing body of knowledge surrounding sensory loss.<\/p>\n While the current mouse-tissue model represents a major leap forward, the ultimate goal of the Tufts team is to translate these findings into a human-derived organoid. Such a model would be transformative for pre-clinical research, providing a bridge between basic cellular discovery and clinical drug development. Human olfactory organoids could be utilized to screen potential therapeutics designed to restore or protect the sense of smell in patients who have suffered permanent loss due to infection, trauma, or degenerative disease.<\/p>\n The development of organoids\u2014miniature, simplified versions of organs grown in a lab setting\u2014has already revolutionized research in other areas of medicine, including lung and kidney studies. These models offer a more accurate representation of human biology than traditional cell cultures and are significantly faster, cheaper, and more ethical than relying on whole-animal models for testing drug safety and efficacy.<\/p>\n However, the creation of a human olfactory organoid faces a unique set of technical hurdles. Extracting pure olfactory tissue from human subjects is a delicate and difficult process. Typically, this involves an anesthetized procedure where a small brush, similar to a COVID-19 testing swab, is inserted deep into the nasal cavity to collect cells. Unlike the clear differentiation observed in the mouse model, the human samples collected via this method contain a mixture of respiratory and olfactory stem cells that are notoriously difficult to isolate.<\/p>\n The research team\u2019s current challenge is to develop a technique that is both cost-effective and efficient for separating these human stem cells and successfully coaxing them to grow and differentiate in a laboratory environment. If they succeed, it would open the door to personalized medicine, where doctors might eventually be able to grow a patient\u2019s own olfactory tissue in the lab to test which drugs could effectively stimulate their specific regenerative pathways.<\/p>\n By proving that even "dormant" stem cells play an active role in maintaining our ability to smell, the Tufts researchers have provided a vital new roadmap for future investigations. As the team continues to refine their model and move toward human applications, the prospect of restoring the sense of smell for millions of people worldwide\u2014whether they have lost it to the lingering effects of a virus or the natural wear and tear of time\u2014becomes an increasingly tangible goal. The integration of this 3D organoid into the broader scientific landscape marks a critical milestone in the ongoing effort to decode the complex biology of the human nose and provide relief for those living in a world deprived of scent.<\/p>\n","protected":false},"excerpt":{"rendered":" In a significant advancement for sensory biology, researchers at the Tufts University School of Medicine and the Graduate School of Biomedical Sciences (GSBS) have unlocked new insights into how the human nose maintains its sense of smell. By developing an innovative, three-dimensional model to observe nerve tissue regeneration, the team has overturned long-held assumptions regarding […]<\/p>\n","protected":false},"author":1,"featured_media":3512,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[650],"tags":[780,652,451,2485,5679,656,1166,666,658,659,651],"class_list":["post-3513","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-health-and-wellness","tag-behind","tag-fitness","tag-health","tag-hidden","tag-mechanisms","tag-model","tag-regeneration","tag-reveals","tag-sense","tag-smell","tag-wellness"],"_links":{"self":[{"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/posts\/3513","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=3513"}],"version-history":[{"count":0,"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/posts\/3513\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=\/wp\/v2\/media\/3512"}],"wp:attachment":[{"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3513"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3513"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xesi.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3513"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}An Easy-To-Use Model for Global Research<\/h3>\n
The Path Toward Human Organoids<\/h3>\n