#25 Pathogen Taxis, New Lung Cells and Increasing Temperature - Increasing Pandemics?
A new type of human lung cells has been discovered, how climate change could be responsible for future pandemics and how pathogens can "hitch a ride" to the sea on plastic pollution...
🫁New Lung Cells
New type of human lung cell discovered…
The newly discovered cells, RASCS (respiratory airway secretory cells) line the tiny airway branches near the alveoli structures where gaseous exchange occurs and oxygen is exchanged for carbon dioxide. An unusual feature of this cell type is their ability to regenerate. Similar to stem cells, they have properties that enable them to regenerate other cells that are essential for the functioning of the vital alveoli.
The research team from the University of Pennsylvania School of Medicine found evidence that cigarette smoking and the associated disease COPD (chronic obstructive pulmonary disease) can disrupt these cells regenerative function. Therefore suggesting that correcting this disruption could present a method to treat COPD.
“COPD is a devastating and common disease, yet we really don’t understand the cellular biology of why or how some patients develop it,” said Dr Maria Basil, a researcher in the Department of Medicine at the University of Pennsylvania. Identifying new cell types, in particular new progenitor cells, that are injured in COPD could really accelerate the development of new treatments.”
The research team found the evidence of RASCs whilst examining the gene activity signatures of lung cells sampled from healthy human donors. The team soon realised that RASCs, which don’t exist in mice, are actually secretory cells residing near alveoli. One of the functions of this new cell is to produce proteins needed for the fluid lining of the airway.
Observations of gene activity in both RASCs as well as a progenitor cell in the alveoli called AT2, showed a similarity. In addition to their secretory function, they serve as predecessors for AT2 cells. Regenerating them to maintain the AT2 population within the area and so keeping the alveoli healthy.
AT2s are commonly known to become abnormal in COPD and other lung diseases. The research team and authors of the study found evidence to suggest that defects in RASCs could be an upstream cause of the abnormalities. The importance of these new cells could be huge with their functionality and reduced functionality having knock on effects throughout the lung. Lung tissue from people with COPD as well as those without COPD but who smoke, had AT2 cells that were altered in a way that hinted at a faulty RASC-AT2 transformation.
“More research is needed, but the findings point to the possibility of future COPD treatments that work by restoring the normal RASC-to-AT2 differentiation process — or even by replenishing the normal RASC population in damaged lungs,” Professor Morrisey, one of the authors, said.
📈Increasing Temperatures and Increasing Pandemics?
Climate change could trigger the next pandemic…
As we all know, climate change is altering and negatively affecting ecosystems across the world in numerous direct and indirect ways. Global warming and climate change continues to increase, forcing wild animals to relocate. Studies suggest that as the Earth continues to warm, wild animals will relocate to a greater extent, likely into human inhabited urban areas. This drastically increases the viral jump to humans as seen with the recent COVID-19 pandemic.
This recent study sees the first comprehensive assessment of how climate change will likely restructure the global mammalian virome. This study not only focuses on the direct virology, but the geographic range shifts. With an ever increasing “intercrossing” of new animal species into different areas and climates, they predict that thousands of viruses will be shared. Resultantly their are greater opportunities for viruses like Ebola or coronaviruses to emerge in new areas.
Colin Carlson, PhD and assistant research professor said that “The closest analogy is actually the risks we see in the wildlife trade”. “We worry about markets because bringing unhealthy animals together in unnatural combinations creates opportunities for this stepwise process of emergence — like how SARS jumped from bats to civets, then civets to people. But markets aren’t special anymore; in a changing climate, that kind of process will be the reality in nature just about everywhere.”
An additional finding is the impact that the rising temperatures will have on bats. Bats account for the majority of novel viral-sharing and their ability to fly allows the virus to be spread to an even greater extent. Due to their central role in viral emergence the greatest impacts are projected for southeast Asia. With growing populations and increased globalisation the chance of a zoonotic disease being transmitted to humans is always increasing.
“At every step,” said Carlson, “our simulations have taken us by surprise. We’ve spent years double-checking those results, with different data and different assumptions, but the models always lead us to these conclusions. It’s a really stunning example of just how well we can, actually, predict the future if we try.”
However, this study is still a positive. The team went on to say how we are closer than ever to predicting and importantly preventing the next pandemic. Being able to locate the most likely location and species increases the chance of the pandemic being prevented or largely limited. “This is a big step towards prediction — now we have to start working on the harder half of the problem” said the team.
Pathogens could hitch a ride to the sea on plastic pollution…
This recent study found how land based pathogens are not only connected to microplastics in the ocean, but that microplastics can make it easier for disease causing pathogens to concentrate in specific areas of the ocean and as a result infect a variety of marine species.
The three pathogens studies were Toxoplasma gondii, Cryptosporidium (Crypto) and Giardia. Recognised as underestimated causes of illness from shellfish consumption by the WHO, they can infect both humans and animals and are found throughout the ocean.
"It's easy for people to dismiss plastic problems as something that doesn't matter for them, like, 'I'm not a turtle in the ocean; I won't choke on this thing,'". "But once you start talking about disease and health, there's more power to implement change. Microplastics can actually move germs around, and these germs end up in our water and our food” said Karen Shapiro, author of the study and infectious disease expert.
T. gondii has infected many ocean species with the disease toxoplasmosis. A notable victim of this parasite being the sea otter with many deaths connected to this species.
The authors and research team associated with the study conducted lab experiments to test the extent, if any, of the association between the selected pathogens and plastics in seawater. The team found that microfibres were an especially good “taxi” for the parasite, though both microfibres and microbeads could carry the land pathogens.
Plastic makes it easier for the pathogens to reach the sea life in several ways depending on the plastic and whether it sinks or floats. Those that float simply carry the pathogen from their sources on land, and can do so to a wide geographical region. Those that sink tend to concentrate pathogens in the benthos environment nearer the bottom of the sea. Filter feeding animals such as zooplankton, mussels and oysters have an increased likelihood of then ingesting both pathogens and plastic.
Not only are we altering natural food webs by introducing a human made material, but it carries deadly parasites too. This work further demonstrates the importance of preventing sources of microplastics to our oceans.
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🫁New Lung Cells
Basil, M., Cardenas-Diaz, F., Kathiriya, J., Morley, M., Carl, J., Brumwell, A., Katzen, J., Slovik, K., Babu, A., Zhou, S., Kremp, M., McCauley, K., Li, S., Planer, J., Hussain, S., Liu, X., Windmueller, R., Ying, Y., Stewart, K., Oyster, M., Christie, J., Diamond, J., Engelhardt, J., Cantu, E., Rowe, S., Kotton, D., Chapman, H. and Morrisey, E., 2022. Human distal airways contain a multipotent secretory cell that can regenerate alveoli. Nature, 604(7904), pp.120-126.
📈Increasing Temperatures and Increasing Pandemics?
Carlson, C., Albery, G., Merow, C., Trisos, C., Zipfel, C., Eskew, E., Olival, K., Ross, N. and Bansal, S., 2022. Climate change increases cross-species viral transmission risk. Nature,.
Zhang, E., Kim, M., Rueda, L., Rochman, C., VanWormer, E., Moore, J. and Shapiro, K., 2022. Association of zoonotic protozoan parasites with microplastics in seawater and implications for human and wildlife health. Scientific Reports, 12(1).