Michael Shiloh, MD, PhD

This work was a collaborative effort between @utswinfdis.bsky.social @utswim.bsky.social and @scripps.edu, and I’m grateful to Ben Cravatt and the Cravatt lab for their contributions. Supported by @niaidnews.bsky.social

This work uses cysteine-directed activity-based protein profiling to map infection-induced proteome changes in human macrophages and identify host proteins that regulate intracellular Mtb replication.

Cysteine Reactivity Profiling Identifies Host Regulators of Mycobacterium tuberculosis Replication in Human Macrophages Innate immune cells, such as monocytes and macrophages, provide the earliest defense against intracellular pathogen infection by initiating signaling pathways and restricting pathogen replication. However, the full complement of proteins that mediate cell-autonomous immunity remains incompletely defined. Here, we applied cysteine-directed activity-based protein profiling (ABPP) to map proteome-wide cysteine reactivity changes in THP-1 monocytes and primary human monocyte-derived macrophages during Mycobacterium tuberculosis (Mtb) infection. Across both cell types, we quantified 148 cysteine residues with altered reactivity. Knockdown of a subset of proteins harboring infection-induced reactivity significantly altered Mtb replication in THP-1 monocytes, linking proteins with reactive cysteines to antimicrobial defense. These data define previously unrecognized host protein changes during Mtb infection and provide a resource for investigating post-translational events that regulate innate immune responses to intracellular bacteria.

Our paper, Cysteine Reactivity Profiling Identifies Host Regulators of Mycobacterium tuberculosis Replication in Human Macrophages, is now out. Congratulations to John Neff and Kristen DeMeester on their many years of dedication to bring this project to completion.
pubs.acs.org/doi/full/10....

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Assistant/Associate Professor, Microbiology and Molecular Genetics - McGovern Medical School in Texas, United States | Faculty & Physicians at UTHealth Houston Apply for Assistant/Associate Professor, Microbiology and Molecular Genetics - McGovern Medical School job with UTHealth Houston in Texas, United States. Faculty & Physicians at UTHealth Houston

My alma mater is hiring a microbiologist! Assistant/Associate Prof. 👇👇

Many thanks to @niaidnews.bsky.social for their support for this work. This project was done at UTSW @utswim.bsky.social in the Division of Infectious Diseases @utswinfdis.bsky.social.

Together, these results identify USP15 as a conserved and targetable suppressor of xenophagy. Inhibiting USP15 could boost the host’s own ability to control Mtb, indicating a potential path for host-directed TB therapy to augment existing antibiotics or shorten treatment duration.

A selective small-molecule USP15 inhibitor mimicked the genetic effects of knocking down USP15 in most human donors tested, lowering Mtb burden without harming the host cells.

We saw the same effects in primary mouse macrophages and in human monocyte-derived macrophages. Even partial knockdown of USP15 reduced Mtb growth and increased LC3 targeting.

The picture became clearer when we looked at PARKIN. This E3 ligase normally promotes K63 ubiquitination of Mtb, leading to it's destruction. Depleting PARKIN reversed the enhanced antibacterial effects seen in USP15-deficient cells, pointing to a direct antagonism between PARKIN and USP15.

Restoring wild-type USP15 to macrophages genetically lacking USP15 rescued Mtb growth, while a catalytically inactive mutant did not — highlighting the importance of USP15's enzymatic activity for its immune-suppressive role.

LC3B (green) surrounding intracellular Mtb (red) in macrophages lacking USP15

Without USP15, K63 ubiquitin piled onto Mtb-associated structures, LC3 recruitment increased, and bacterial replication was reduced. Blocking autophagy initiation removed this benefit, showing the effect depends on canonical autophagy.

We screened murine deubiquitinases for effects on intracellular Mtb growth. One stood out — USP15. Knocking it down or knocking it slowed the growth of Mtb in macrophages.

Macrophages can mark Mtb-associated structures with K63-linked ubiquitin, drawing in LC3 and the autophagy machinery to degrade the bacteria. But some host enzymes remove these marks, tipping the balance in favor of the pathogen.

Deubiquitinase USP15 restricts autophagy and macrophage immunity to Mycobacterium tuberculosis Autophagy enables macrophages to degrade intracellular Mycobacterium tuberculosis (Mtb), and this defense depends on E3 ubiquitin ligases such as PARKIN and SMURF1, which tag Mtb-associated structures...

Congratulations to Kathryn Rahlwes and the rest of the team on the new preprint from our group. We identify USP15, a deubiquitinase, as a key brake on macrophage immunity to Mycobacterium tuberculosis (Mtb). Remove it, and macrophages control Mtb far more effectively.
www.biorxiv.org/content/10.1...

Congrats @samuelalvarez.bsky.social and the entire team on this work characterizing established (i.e. M cells) and new cells in the mucosal immune system! The new cells we named WISP cells as they are found in both adenoid and tonsils. Read the paper to find out so much more!

A Diagnostic Stewardship Success: Implementing a Urine Culture Reflex Policy in the Emergency Department of a Large Safety-Net Hospital AbstractBackground. Urinalyses and urine cultures (UCs) are frequently ordered simultaneously in emergency departments (EDs) to increase efficiency and dec

Similar to this study.
academic.oup.com/ofid/article...

Quantifying Dissemination of Antibiotic Resistance Genes in Air from a Dairy Farm and Swine Farm Farms are a suspected source of dissemination of antibiotic resistance genes (ARGs) to the atmosphere, but their contribution remains poorly quantified. This study investigated the concentrations, emi...

Quantifying Dissemination of Antibiotic Resistance Genes in Air from a Dairy Farm and Swine Farm, led by PhD student David Kormos, now published! We found ARGs in a range of particle sizes, indicating potential for inhalation exposure and long-range transport.

pubs.acs.org/doi/10.1021/...

Mycobacterium tuberculosis sulfolipid-1 (Sl-1) increases the excitability of mouse and human TRPV1-positive sensory neurons in a YM254890-reversible fashion Cough is a hallmark sign of tuberculosis and key driver of transmission. While traditionally attributed to host-driven inflammation, we previously demonstrated that Mycobacterium tuberculosis lipid ex...

Congrats to Dhananjay Naik from @tedpricethepainguy.bsky.social's lab at UT Dallas on their new preprint deeply characterizing the nociceptive activity of SL-1 on mouse & human neurons.
www.biorxiv.org/content/10.1...

Enjoyed celebrating John Neff’s PhD graduation ceremony yesterday.

I get the cartoonist's point, but, if I'm going to be pedantic (and scientifically accurate), since measles is an airborne disease with the highest transmissibility of all pathogens, the girl on the left would have been exposed/infected in the top left panel.

I wish I could find it online, but 30 years ago my PhD advisor had a cartoon on his door (maybe New Yorker?), with 3 spinning-wheels. On one was "eggs, butter, fat, sugar, coffee, etc.", then "causes, cures, etc." and the last "cancer, heart disease, stroke, etc." So, I think the answer is "yes".

Thank you Olivier!

Thank you Kat!

Ted Lasso Thank You GIF - Ted lasso Thank you Mercy buckets - Discover & Share GIFs Click to view the GIF

This project would not have been possible without the financial support of @niaidnews.bsky.social ws.bsky.social, @bwfund.bsky.social nd.bsky.social, and @thewelchfoundation.bsky.social. 14/14
tenor.com/view/ted-las...

All credit belongs to Kubra Naqvi, PhD (not yet on Bluesky), who led this project from the start. We are also indebted to our chemistry collaborators at @unileiden.bsky.social and neuroscience collaborators @utdpaincenter.bsky.social. 13/14

Mycobacterial Phenolic Glycolipid Triggers ATP-Mediated Neuronal P2X3 Signaling and Cough Cough drives respiratory pathogen transmission, yet how microbes directly engage host sensory neurons to trigger cough is largely unknown. We previously demonstrated that the Mycobacterium tuberculosi...

Please check out and share our preprint relating to the aerobiology of one of the most successful human pathogens, Mtb. 12/14 @idsainfo.bsky.social sky.social @utswinfdis.bsky.social is.bsky.social @carlzimmer.com
#InfectiousDisease #Purinergic #DrugDiscovery
www.biorxiv.org/content/10.1...

We propose that Mtb evolved to produce multiple neuron activating molecules to co-opt the host cough reflex, thus facilitating its own spread from person to person. Therapeutically, P2X3 antagonists may help reduce airborne transmission of Mtb. 11/14

An image showing the role of ATP in neuronal activation

PGL triggers rapid extracellular ATP release from host cells through pannexin channels. ATP then binds neuronal P2X3 purinergic receptors. Blocking P2X3 with a specific antagonist inhibits PGL-mediated neuronal activity. ⚠️. #anti-tussive 10/14

A picture of animals and their mycobacterial hosts

PGL is also made by other mycobacteria, like M. bovis, M. leprae, M. marinum and M. kansasii. By organically synthesizing PGL analogs, we found that neuroactivity is proportional to saccharide chain length & structure. Mtb PGL triggers the most robust activity with the lowest EC50, 30 pM! 9/14