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New Insights into Sensory Neurons of Sea Anemones Reveal Evolutionary Links to Human Kidney Disease
Researchers from the University of Alberta (U of A) have contributed to an important study that deepens our knowledge of sensory neurons in sea anemones, uncovering connections to kidney disease in humans via a shared genetic component.
The team focused on the evolutionary origins of auditory capabilities in humans, particularly through the study of mechanosensory hair cells located on the tentacles of sea anemones. Mechanosensation encompasses both the ability to hear and the sense of touch, with hair cells serving as specialized auditory receptors found within the inner ear of vertebrates. Similarly, sea anemones possess these hair cells, which play a crucial role in detecting the movement of prey in their aquatic environment.
In their paper, published in Nature Communications, the primary author, Nagayasu Nakanishi, an associate professor of biological sciences at U of A, outlined the discovery that the polycystic kidney disease 1 (PKD-1) gene, implicated in kidney disorders in humans, is also present in sea anemones. This gene is integral to the functionality of hair cells in these organisms, enabling them to sense the flow of water around them and react accordingly.
The dual role of PKD-1 as a fluid sensor in kidney cells and a critical component for auditory function in mammals implies a primordial role for this gene in the fluid-sensing mechanisms that predate the common ancestor of mammals and sea anemones, dating back over 580 million years.
Cnidarians, a category that includes jellyfish, corals, and sea anemones, are considered the closest existing relatives to bilaterally symmetrical organisms such as humans and insects. While it is easy to underestimate the complexity of creatures like sea anemones, they share many genes with humans, including those associated with vital biological functions and severe health conditions.
These findings position cnidarians as promising subjects for studies on human evolutionary biology. Common features in bilateral animals and cnidarians suggest that many shared genetic traits were inherited from a distant common ancestor. Notably, the mechanosensory system exhibits considerable genetic similarities in the development of mechanoreceptors across these groups.
In a surprising turn, the researchers identified not just a single variety of mechanosensory neuron on the tentacles of sea anemones, as previously believed, but at least two distinct types of hair cells. This suggests a potentially more intricate mechanosensory system than previously assumed, originating from an ancestral lineage that diverged over 580 million years ago—or indicates that diversity in mechanosensory neuron types arose independently in these organisms and their close relatives like jellyfish. Such revelations mark a crucial advancement in our understanding of the evolution of mechanosensory systems in animals and the basic principles underlying human mechanosensation.
“The culmination of years of dedicated research by undergraduate and graduate students, along with our mentor Dr. Nakanishi, is reflected in this paper,” stated Baranyk, a Ph.D. student in biological sciences and the lead author. “It’s incredibly gratifying to see our findings shared with the scientific community and to provide inspiration for future research endeavors.”
Nakanishi expressed his excitement about the team’s achievements: “Witnessing our students grow as scientists through various challenges and breakthroughs in our experiments has been immensely rewarding. It’s fulfilling to see their discoveries pave the way for even more significant contributions in the field.”
Out of the six co-authors of the paper, five are linked to the U of A. In addition to Baranyk and Nakanishi, Miguel Silva, who was pursuing an M.Sc. in biological sciences, contributed, along with undergraduate co-authors Kristen Malir and Sakura Rieck who worked in the Nakanishi Lab during the study. Gracie Scheve also participated as a visiting undergraduate scholar. Silva and Malir have graduated from their respective programs.
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