TRPC6 channel translocation into phagosomal membrane augments phagosomal function

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 112; no. 47; pp. E6486 - E6495
• Main Authors: Riazanski, Vladimir, Gabdoulkhakova, Aida G., Boynton, Lin S., Eguchi, Raphael R., Deriy, Ludmila V., Hogarth, D. Kyle, Loaëc, Nadège, Oumata, Nassima, Galons, Hervé, Brown, Mary E., Shevchenko, Pavel, Gallan, Alexander J., Yoo, Sang Gune, Naren, Anjaparavanda P., Villereal, Mitchel L., Beacham, Daniel W., Bindokas, Vytautas P., Birnbaumer, Lutz, Meijer, Laurent, Nelson, Deborah J.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 24.11.2015; National Acad Sciences
• Series: PNAS Plus
• Subjects: Acids - metabolism; Animals; Biological Sciences; Calcium - metabolism; Calcium Signaling - drug effects; Cell Line; Cell Membrane - drug effects; Cell Membrane - metabolism; Cystic Fibrosis Transmembrane Conductance Regulator - metabolism; Diglycerides - metabolism; Exocytosis - drug effects; Fluorescent Antibody Technique; Humans; Intracellular Membranes - drug effects; Intracellular Membranes - metabolism; Ion Channel Gating - drug effects; Macrophages, Alveolar - drug effects; Macrophages, Alveolar - metabolism; Mice; Microbial Viability - drug effects; Models, Biological; Patch-Clamp Techniques; Pertussis Toxin - pharmacology; Phagosomes - drug effects; Phagosomes - metabolism; PNAS Plus; Protein Transport - drug effects; Purines - chemistry; Purines - pharmacology; Receptors, G-Protein-Coupled - metabolism; Roscovitine; Small Molecule Libraries - chemistry; Small Molecule Libraries - pharmacology; TRPC Cation Channels - metabolism; TRPC6 Cation Channel; phagosome; alveolar macrophage; TRPC6; cystic fibrosis; roscovitine
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1518966112

Defects in the innate immune system in the lung with attendant bacterial infections contribute to lung tissue damage, respiratory insufficiency, and ultimately death in the pathogenesis of cystic fibrosis (CF). Professional phagocytes, including alveolarmacrophages (AMs), have specialized pathways that ensure efficient killing of pathogens in phagosomes. Phagosomal acidification facilitates the optimal functioning of degradative enzymes, ultimately contributing to bacterial killing. Generation of low organellar pH is primarily driven by the V-ATPases, proton pumps that use cytoplasmic ATP to load H⁺ into the organelle. Critical to phagosomal acidification are various channels derived from the plasma membrane, including the anion channel cystic fibrosis transmembrane conductance regulator, which shunt the transmembrane potential generated by movement of protons. Here we show that the transient receptor potential canonical-6 (TRPC6) calcium-permeable channel in the AMalso functions to shunt the transmembrane potential generated by proton pumping and is capable of restoring microbicidal function to compromised AMs in CF and enhancement of function in non-CF cells. TRPC6 channel activity is enhanced via translocation to the cell surface (and then ultimately to the phagosome during phagocytosis) in response to G-protein signaling activated by the small molecule (R)-roscovitine and its derivatives. These data show that enhancing vesicular insertion of the TRPC6 channel to the plasma membrane may represent a general mechanism for restoring phagosome activity in conditions, where it is lost or impaired.