How the study of the human nasal microbiome can help reveal aspects of human variation and respiratory conditions.
This web page was produced as an assignment for an undergraduate course at Davidson College.
Since the turn of the 21st century, technology has been evolving exponentially, from self-driving cars to generative A.I. to I argue that the most impressive developments, however, have been in the realm of medical technology. An interesting example of this is the blossoming field of genomics, which allows us to investigate and understand the extensive variation in humans and numerous other species through sequencing and comparing genomes. This field began to gain traction with the publishing of the first draft of the human genome in 2001, which provided a reference for future studies of the human genome [6]. This project was extremely time-consuming and expensive, requiring many years of work and collaboration from scientists all over the world. Since this project, genomic research has only become more efficient, accessible, and cheaper, making Genome-Wide Association Studies (GWAS) much easier to perform [5]. A GWAS allows researchers to analyze different variants within a genome and determine if they are related with particular risks or traits [4].
A recent GWAS study performed by Liu and colleagues in January, 2024 looks at the possible connection between genetics, health, and the human nasal microbiome [1]. Although we were previously aware that the nasal microbiome can impact an individual’s risk for respiratory infections and disorders such as asthma, this paper was the first to investigate how our genetics may influence the specific nasal biome that we develop. They used a GWAS method in order to identify the associations between nasal biome variants and variants in the genome of humans, as well as the resulting measurable traits in humans, such as risk for different diseases.
Liu et al. not only sequenced the genomes of over 1400 human participants in the study, but also the genomes of each person’s unique nasal microbiome. This project was only possible because the genomic techniques involved have become much less expensive over time. They used statistical analysis techniques on the human genome to identify different loci, which are locations in the genome, that were associated with variations in nasal biome. Once they had identified approximately 63 significant loci, the researchers performed further analysis to determine what possible impacts these human genetic variants had on the resulting nasal microbiome. They were able to narrow down two genetic loci that were highly significant in predicting the diversity and composition of the resulting nasal microbiome, demonstrating that not only does the nasal microbiome impact human health, but that an individual’s own genome can impact the microbiome that they develop.
Additionally, this study found predicted correlations between the nasal biome and risk for different respiratory conditions, in addition to some unexpected relations between nasal biomes and cardiometabolic and neuropsychiatric disease. These unexpected results demonstrate the complex and unexplored relations between the various microbiomes within the human body and possible health outcomes, even between seemingly unrelated systems. This study adds yet another piece into the constantly evolving puzzle that is the human body, filling a gap left by an important yet underappreciated microbiome that is vital to our survival. Other studies have investigated the role and composition of the oral, fecal, and gastro-intestinal microbiomes, which all contribute to human health and function [2][3]. Similarly to this study, they found unexpected relationships between the microbiomes being studied and various psychosomatic disorders, such as anxiety and depression.
While this study provided valuable information in an area which had not been thoroughly investigated before, the researchers who conducted it admitted that their data was primarily composed of Chinese North-South populations and that they lacked data on the neuropsychiatric diseases of their target population. This prevents them from strongly concluding any causal relationships between the nasal microbiome and any neurological disorders that may have been present in participants. Additionally, although this was the largest study performed in this area so far, it is still relatively small compared to other GWAS studies, and it would be valuable to conduct further research with a larger and more diverse sample size. While they identified some connections between the gut microbiome and nasal microbiome, they were not able to consider those relations adequately in this paper and they suggested that further research be performed in this area. Since the nose is one of the primary entry points for pathogens into the human body, it is an important area to study in order to understand the mechanisms of infection that can impact the whole body. It would be beneficial to investigate the connections between the various microbiomes in the human body, such as nasal, gastro-intestinal, oral, and fecal, and the acquisition of infections and other conditions.
The nose is an important yet often overlooked component of human function and health. Besides providing a mechanism for smelling and breathing, it also contains a microbiome which can contribute to the development of or resilience against various respiratory infections. This study has shed some light on this previously unexplored topic, but there is likely much more we have yet to understand about the relationships between the nasal biome and the human genome. We may be able to gain useful insights about the treatment and prevention of common human conditions and risks of respiratory infection, or we may find connections between the various microbiomes present throughout the human body but, then again, who nose?
Bibliography:
1.Liu, X. et al. A genome-wide association study reveals the relationship between human genetic variation and the nasal microbiome. Communications Biology 7, (2024).
2.Liu, X. et al. Metagenome-genome-wide association studies reveal human genetic impact on the oral microbiome. Cell Discovery 7, (2021).
3.Kurilshikov, A. et al. Large-scale association analyses identify host factors influencing human gut microbiome composition. Nature Genetics 53, 156–165 (2021).
4.Dehghan, A. Genome-wide association studies. Methods in Molecular Biology 37–49 (2018). doi:10.1007/978-1-4939-7868-7_4
5.Shi, Y., Wang, G., Lau, H. C.-H. & Yu, J. Metagenomic sequencing for microbial DNA in human samples: Emerging technological advances. International Journal of Molecular Sciences 23, 2181 (2022).
6.Lander, E. S. et al. Initial sequencing and analysis of the human genome. Nature 409, 860–921 (2001).
Contact Information:
cahiers@davidson.edu
© Copyright 2022 Department of Biology, Davidson College, Davidson, NC 28036.
First off, love the name of the article, really got me hooked. I enjoyed reading the article – I thought that you managed to make it informative yet not too complicated. I was left wondering about the categorization of the nasal biome. In most of the GWAS studies we’ve read, they usually test for a specific trait or disease associated with unusual instances of genetic variation. But here, it seems that they were just looking at different kinds of nasal microbiomes, and correlating those with different levels of genetic variation. How did they decide what constituted a specific nasal biome, and what non-obvious variables were controlled to ensure that they were only looking at genetic locations that influenced this specific trait?
I also got drawn in by the title, and the ending was pretty good too. I really enjoyed reading this article. I thought the flow from start to finish was really good, starting broad with background information about GWAS and then narrowing in to the nose microbiome. This is also a topic that I haven’t thought much about and it was interesting to learn that genomes may have control over the complexion on microbiomes in our body. I also liked that you mentioned studies of other microbiomes to inform us of the similar studies and their results. I definitely felt like I learned something interesting and actually gained a good understanding of it after reading this.