New Publication: Neutrophil-mediated innate immune resistance to bacterial pneumonia is dependent on Tet2 function

https://bsky.app/profile/msmacrophage.bsky.social/post/3kubwknbcts2e
Click here for the full thread from Bluesky highlighting the major findings of the paper.
To see the full paper click here:
To see the commentary click here:



Bluesky thread:

Let me tell you about the #BowdishLab & friend’s most recent paper “Neutrophil-mediated innate immune resistance to bacterial pneumonia is dependent on Tet2 function”, led by Dr. C. Quin (now at @uniofaberdeen.bsky.social) @jclinical-invest.bsky.social https://www.jci.org/articles/view/171002
Tet2 is gene that is involved with methylating genes and therefore changing gene expression. Sometimes spontaneous mutations of Tet2 in hematopoetic stem cells (HSC) occur. These mutants tend to produce more myeloid cells (monocytes/neutrophils).
These myeloid producing HSCs tend to be more fit in the aging bone marrow (Darwinian survival of the fittest) and overtime, more and more of your myeloid cells are made from these Tet2 mutant clones.
In extreme cases this can lead to myelodysplastic disorders or cancer, but sub-clinical CHIP or clonal hematopoeisis of indeterminant potential occurs in many older adults.
People with CHIP (i.e., too many of their myeloid cells are made from Tet2 mutant progenitors) are prone to all sorts of conditions (e.g., heart disease) and pneumonia. We hypothesized that pneumonia risk might be due to changes in innate immune/myeloid cell function.
Mice defective in Tet2 did very poorly during Streptococcus pneumoniae infection (the most common cause of community acquired pneumonia in older adults), because their neutrophils were less able to kill bacteria.
We are excited about this @jclinical-invest.bsky.social publication because it is the first mechanistic explanation for the increased risk of pneumonia in CHIP. Generally CHIP is thought to affect macrophage function, but it clearly affects neutrophil gene expression & function as well.
Many thanks to Dr. Elsa Bou Ghahem for her most excellent Commentary https://www.jci.org/articles/view/181064 and for the great editorial & reviewer experience @jclinical-invest.bsky.social
Research Team:Candice Quin, Erica N. DeJong, Elina K. Cook, Yi Zhen Luo, Caitlyn Vlasschaert, Sanathan Sadh, Amy J.M. McNaughton, Marco M. Buttigieg, Jessica A. Breznik, Allison E. Kennedy, Kevin Zhao, Jeffrey Mewburn, Kimberly J. Dunham-Snary, Charles C.T. Hindmarch, Alexander G. Bick, Stephen L. Archer, Michael J. Rauh, Dawn M.E. Bowdish

Dr. Bowdish discusses the lab’s research on microbiota and healthy/unhealthy aging on the Agora Health Podcast

Or listen on

Apple podcasts https://podcasts.apple.com/co/podcast/how-the-microbiome-can-affect-your-overall-health-and/id1712499485?i=1000642050180&l=en-GB

Spotify: https://open.spotify.com/episode/0flH90zGfa5bXAVoy1ZiiF?si=f3680075df4b4a2a

Amazon Music: https://music.amazon.com/podcasts/2e2f7513-9491-40e9-a9dc-a31859560d1d/episodes/fce86aa3-0d05-4245-ab87-08be6b86323b/decoding-healthcare-research-how-the-microbiome-can-affect-your-overall-health-and-its-effects-on-aging-ep-15

Dr. Jessica Breznik talks about her research in the American Journal of Physiology-Gastrointestinal and Liver Physiology Podcast

In this podcast first author Dr. Jessica A. Breznik of McMaster University, discusses the recently published manuscript titled “Diet-induced obesity alters intestinal monocyte-derived and tissue-resident macrophages and increases intestinal permeability in female mice independent of tumor necrosis factor.” 

NEW & NOTEWORTHY We found that diet-induced obesity in female mice has tissue- and time-dependent effects on intestinal paracellular permeability as well as monocyte-derived and tissue-resident macrophage numbers, surface marker phenotype, and intracellular production of the cytokines IL-10 and TNF. These changes were not mediated by TNF.

Article Citation: Diet-induced obesity alters intestinal monocyte-derived and tissue-resident macrophages and increases intestinal permeability in female mice independent of tumor necrosis factorJessica A. Breznik, Jennifer Jury, Elena F. Verdú, Deborah M. Sloboda, and Dawn M. E. Bowdish

American Journal of Physiology-Gastrointestinal and Liver Physiology 2023 324:4, G305-G321

Congratulations to Pat Schenck & Jessica Breznik on winning the Farncombe Research in Progress Awards!

Jessica Breznik (co-supervised by Dr. Deborah Sloboda) won the “Best Presentation by a PhD student” while Pat Schenck (co-supervised by Dr. Mike Surette) won runner up!  What a wonderful tribute to their skills in both research and communication – well done!

Publication: Age-associated Inflammation alters the aging trajectory.

This article is written for lay/broad audiences and describes what age-associated inflammation is and why it may be key to healthy/unhealthy aging.

November is Lung Month – what do older adults need to know about pneumonia?

Dr Bowdish is the Canadian Lung Association’s spokesperson for World Pneumonia Day (November 12, 2018). Here she discusses the importance of being vaccinated for pneumonia….

She also speaks to Zoomer Magazine about pneumonia, vaccinations and the aging immune system here…

To get a sense of the other lung research going on in the Bowdish lab, see our Instagram page: house.macrophage

>

Publication: Myeloid-Derived Suppressor Cells in Aged Humans

Myeloid-Derived Suppressor Cells in Aged Humans

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells whose
immunosuppressive activities contribute to cancer and other diseases. MDSCs
appear to increase with age, and this presumably contributes to immunosuppression
and the increased incidence of certain diseases. Why MDSCs increase with
age is not entirely clear. Herein we present evidence that MDSC expansion is due
in part to age-related changes in hematopoiesis, including the acquisition of
mutations that favor myelopoiesis, which are compounded by changes in the
aging microenvironment that favor the production of MDSCs.