New paper online at Cell Calcium

Derek's paper is now online at Cell Calcium (McMahon, et al., https://doi.org/10.1016/j.ceca.2021.102499). 

Years of tenacious work revealed important changes in T2R signaling that occur with airway epithelial squamous de-differentiation. This paper is a tour-de-force of live cell imaging of indicator dyes and genetically encoded targeted probes for subcellular calcium imaging.  We're very proud of this work, and it may reveal novel pathogenic mechanisms in disease where airway de-differentiation occurs, such as COPD, asthma, or chronic rhinosinusitis.  

Rather than activating calcium in cilia to increase NO production and ciliary beating, T2R activation in non-ciliated airway cells induces strong nuclear calcium responses that propagate to the mitochondria.  This results in mitochondrial depolarization, caspase activation, and apoptotic cell death. This may be a last-resort defense against bacterial infection. However, it may also increase susceptibility of de-differentiated or remodeled epithelia to damage by bacterial metabolites. Moreover, the T2R-activated apoptosis pathway occurs in airway cancer cells. T2Rs may thus contribute to microbiome-tumor cell crosstalk in airway cancers. Targeting T2Rs may be useful for activating cancer cell apoptosis while sparing surrounding tissue.  

Congrats, Derek!

New paper online at Molecular Oncology

Ryan's paper is now online at Molecular Oncology (Carey, et al., https://doi.org/10.1002/1878-0261.13131).  

This paper goes from sub-cellular calcium imaging to patient outcomes, showing important roles for T2Rs in head and neck cancer.  We're very proud of this awesome paper!  Congrats Ryan!

New paper online at Nutrients

Ryan Carey has a paper with out today in Nutrients: "Neuropeptide Y Reduces Nasal Epithelial T2R Bitter Taste Receptor–Stimulated Nitric Oxide Production" Great work, Ryan!  https://doi.org/10.3390/nu13103392

In a nutshell, NPY may be elevated in the airways in sinus diseases or in asthma. NPY is also one of few negative regulators of airway cilia beating (via NPY2R receptors and PKC). This paper shows the same NPY2R/PKC pathway reduces cilia bitter receptor NO, linking NPY with impaired innate defense.

Airway neuropeptides (NPY, VIP, SubP, etc.) have diverse effects via GPCRs on airway epithelial & immune cells. While likely important for airway physiology & pathophysiology, we still don't know enough about how they influence these cells. Because T2R bitter receptor signaling to eNOS and production of NO controls other responses (like macrophage phagocytosis), NPY (or related PP or PYY) may also reduce T2R-mediated responses in other tissues (but likely depends on NPYRs expressed there). How do other neuropeptides regulate T2R responses in the airway? Stay tuned.

Congrats Zoey!

Congratulations to Zoey on an excellent PGG post-rotation talk to end her first year of grad school.  That's a huge accomplishment in normal times let alone a pandemic.  Way to go, Zoey!

Welcome Jenn!

Year-out Penn med student Jenn Jolivert joined the lab to help work on bitter receptors in head and neck cancer over the year.  Welcome Jenn!  We hope you have a great research experience!

Farewell, Li Eon!

Today was Li Eon's last day.  He is leaving for a position as the scientific director of the Citrin Foundation in Singapore. We are sad to see him go, but we are excited about this new opportunity and new direction in his career path.  Li Eon joined us as a postdoc in 2018 and became a master of primary airway epithelial cell culture.  He was an expert on all things cilia, and wrote an excellent review last year in AJP Lung.  We expect him to do great things in his career and look forward to hearing about all of his future accomplishments.  We wish the best to Li Eon as he takes this next exciting step in his life.  We will work hard to continue all of the great projects he started during his time in the lab.

Welcome Zoey!

Pharmacology grad student Zoey Miller joined the lab to work on bitter taste receptor signaling in head and neck cancer.  Welcome Zoey!  We hope you have a great time in the lab and we look forward to all the great things you will do.

New preprints online

Two new preprints from the lab are up on bioRxiv: 

 
"The bitter end: T2R bitter receptor agonists elevate nuclear calcium and induce apoptosis in non-ciliated airway epithelial cells" by Derek McMahon, et al., available here.

and

"T2R bitter taste receptors regulate apoptosis and may be associated with survival in head and neck squamous cell carcinoma" by Ryan Carey, et al., available here.

First, postdoc Derek McMahon shows bitter receptors (T2Rs) in non-ciliated airway cells regulate nuclear calcium to induce caspase activation. There are important implications for airway diseases w/ squamous remodeling (eg, CRS, CF, etc.). Similar mechanisms occur in airway cancer cells. We hypothesize that airway tumor-microbiome crosstalk may occur via T2R activation by bacterial homoserine lactones, quinolones, etc. There is a lot to explore further! Derek's paper is also a technical tour de force of live cell imaging of indicator dyes, targeted biosensors to measure sub-cellular calcium, etc. There is lots of tenacious work in there. Nuclear calcium and nuclear GPCRs are very unexplored in airway epithelium.

Taking the observation further, senior Penn NET resident Ryan Carey looked at T2Rs in squamous oral cancer cells & found similar mechanisms (T2Rs, nuclear calcium, apoptosis). Ryan's data suggests T2R agonists, particularly in high doses in accessible anatomic sites (like the oral cavity), might be therapeutic for HNSCC. Ryan analyzed The Cancer Genome Atlas and found increased T2R expression is beneficial for HNSCC survival. Perhaps T2Rs are a new type of HNSCC biomarker (requires lots of followup). This was amazing work for a resident research project!

There is a lot of new stuff for them/the lab to follow up on and new leads to pursue, but I'm very proud of their hard work, taking us further in both old & new directions for T2Rs in human epithelial biology w/ translational potential. While others have shown or suggested roles for T2Rs in apoptosis and cancers, Derek showed unique mechanisms to how/why T2Rs signal to apoptosis. Ryan showed an important relevance to a human cancer where activating T2Rs (e.g., via a mouth rinse) is very doable, not just a "what if" scenario.

New paper at AJP Lung

Our new paper on PAR-2 & calcium signaling in nasal gland cells is online at AJP-Lung. Lots of cool techniques were used, from single cell fluid secretion measurements, calcium imaging, polarized epithelial secretion, and a fluorescent GPCR biosensor.

"PAR-2-activated secretion by airway gland serous cells: role for CFTR and inhibition by Pseudomonas aeruginosa" by Derek McMahon, et al. is available here.

New cilia review online

Li Eon wrote a review for AJP Lung and the accepted version is freely available online.  It describes almost everything known about the role of cilia in bacterial, viral, and fungal host pathogen interactions.  I hope it becomes a useful resource for people in the field of respiratory infections, particularly as COVID19 draws more attention to the importance of better understanding the respiratory mucosa.  

New PAR-2 paper now online

A study done by Ryan Carey, Jenna Freund, and Ben Hariri from the lab is now online at Journal of Biological Chemistry.  In it, we show that changes in epithelial composition during deciliation driven by type 2 inflammation, cigarette smoke exposure, or retinoic acid deficiency result in altered polarization of PAR-2 receptor signaling.  Normally, the receptor resides on the basolateral side of the membrane in polarized ciliated cells.  When these cells are replaced with squamous cells, PAR-2 signaling from the apical membrane of these cells may enhance inflammatory responses to inhaled proteases produced by fungi, dust mites, or other organisms.  This may contribute to the pathophysiology of inflammatory airway diseases, many of which are characterized by alterations of airway cell composition and loss of airway cilia. 

COVID-19 temporary closure

Our lab is currently closed for the COVID-19 epidemic.  We and other labs are on a strict “work from home only” directive from Penn. This is the right call for the health and safety of all lab members and for other researchers at Penn. I hope that all grad student and postdocs as well as all other researchers are reminded, now more than ever, that their health and safety is more important than generating data. 

We will return to the lab as soon as we can to continue trying to better understand airway biology, but until then we hope everyone stays safe and healthy. Please follow the advice of the public health professionals and epidemiologists. Please practice social distancing and good hygiene to reduce the spread of this devastating virus. We hope everyone gets through this difficult time as smoothly as possible. 

Our thanks go out to the virologists and physicians working on the front lines to treat patients and develop new treatments for this virus. Out hearts go out to those suffering. Please be kind to one another and let’s all do our part to reduce virus transmission through our communities. We wish you all the best.

Macrophages use bitter taste receptors to "eat" bacteria

Our macrophage paper is online at Cellular and Molecular Life Sciences. We show that macrophages use bitter taste receptors to detect bacterial products and stimulate phagocytosis. The paper includes work from Indi and Jenna. 

Macrophages use a signal transduction pathway downstream of T2Rs similar to airway cells, but with a different physiological output (phagocytosis vs cilia beating in the airway). Targeting T2Rs in macrophages might be beneficial in certain types of bacterial infections.  Moreover, activation of T2Rs in macrophages by bitter plant products or bitter pharmaceuticals might explain some effects of homeopathic remedies or off target effects of clinical drugs.   

Congrats Indi!

Congrats to Indi for receiving a Travel Award from the American Society for Pharmacology and Experimental Therapeutics to present her work at the ASPET Annual Meeting at Experimental Biology 2020 in San Diego, CA. 

This award is presented to outstanding young scientists to enable them to present their research at one of the largest biological scientific meetings in the world. The Experimental Biology meeting is a gathering of more than 12,000 scientists from over 65 countries representing the fields of anatomy, physiology, biochemistry, pathology, and pharmacology. 

Great work!

New PAR-2 preprint on bioRxiv

We have a new preprint online at bioRxiv.  Data from Ryan, Jenna, and Ben show that squamous metaplasia and loss of cilia changes the polarity of protease-activated receptor 2 (PAR-2) signaling in nasal epithelial cells.  Altered PAR-2 polarization in dedifferentiated or remodeled epithelia may contribute to increased sensitivity to inhaled protease allergens in inflammatory airway diseases.  We also confirmed previous studies that PAR-2 can be activated by the common airway fungal pathogen Aspergillus fumigatus.  This study reveals some new insights into changes in airway biology that may contribute to type II inflammatory airway diseases like chronic rhinosinusitis.