Expression of Piwi protein MIWI2 defines a distinct population of multiciliated cells
Gregory A. Wasserman, … , Dónal O’Carroll, Matthew R. Jones
Gregory A. Wasserman, … , Dónal O’Carroll, Matthew R. Jones
Published September 18, 2017
Citation Information: J Clin Invest. 2017;127(10):3866-3876. https://doi.org/10.1172/JCI94639.
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Concise Communication Cell biology Pulmonology

Expression of Piwi protein MIWI2 defines a distinct population of multiciliated cells

Abstract

P-element–induced wimpy testes (Piwi) proteins are known for suppressing retrotransposon activation in the mammalian germline. However, whether Piwi protein or Piwi-dependent functions occur in the mammalian soma is unclear. Contrary to germline-restricted expression, we observed that Piwi-like Miwi2 mRNA is indeed expressed in epithelial cells of the lung in adult mice and that it is induced during pneumonia. Further investigation revealed that MIWI2 protein localized to the cytoplasm of a discrete population of multiciliated airway epithelial cells. Isolation and next-generation sequencing of MIWI2-positive multiciliated cells revealed that they are phenotypically distinct from neighboring MIWI2-negative multiciliated cells. Mice lacking MIWI2 exhibited an altered balance of airway epithelial cells, demonstrating fewer multiciliated cells and an increase in club cells. During pneumococcal pneumonia, Miwi2-deficient mice exhibited increased expression of inflammatory mediators and increased immune cell recruitment, leading to enhanced bacterial clearance. Taken together, our data delineate MIWI2-dependent functions outside of the germline and demonstrate the presence of distinct subsets of airway multiciliated cells that can be discriminated by MIWI2 expression. By demonstrating roles for MIWI2 in airway cell identity and pulmonary innate immunity, these studies elucidate unanticipated physiological functions for Piwi proteins in somatic tissues.

Authors

Gregory A. Wasserman, Aleksander D. Szymaniak, Anne C. Hinds, Kazuko Yamamoto, Hirofumi Kamata, Nicole M.S. Smith, Kristie L. Hilliard, Claudia Carrieri, Adam T. Labadorf, Lee J. Quinton, Xingbin Ai, Xaralabos Varelas, Felicia Chen, Joseph P. Mizgerd, Alan Fine, Dónal O’Carroll, Matthew R. Jones

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Figure 1

Lung epithelial cells express MIWI2.

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Lung epithelial cells express MIWI2. (A) Quantitative real-time PCR of e...
(A) Quantitative real-time PCR of epithelial RNA isolated from mice infected intratracheally (i.t.) with S. pneumoniae. Data represent fold induction over vehicle-treated mice, presented as mean ± SEM, n = 7 mice per group. ***P < 0.001 as determined by unpaired t test. (B) Quantitative real-time PCR of RNA isolated from FACS-sorted cells from mice infected i.t. with S. pneumoniae. Data represent fold induction over leukocyte expression, presented as mean ± SEM, n = 6 mice per group. ***P < 0.001 as determined by 1-way ANOVA, followed by Tukey post hoc test. (C) Immunoblot analysis for HA-MIWI2 after immunoprecipitation with anti-HA antibody, or whole lung lysate from Miwi2+/+ or Miwi2HA/+ mice. Arrow indicates band at expected size of MIWI2 (98 kDa). Image is representative of an experiment performed 3 times. (D and E) Immunostaining with anti-HA antibody of lung sections from Miwi2+/+ or Miwi2HA/+ mice treated with vehicle (D) or infected i.t. with S. pneumoniae (E). Images were acquired using the ×40 objective. (F) Morphometric quantitation was performed by counting of the number of MIWI2-positive cells per airway. At least 3 fields were analyzed from 2 sections per mouse, n = 4 mice per group, presented as mean ± SEM. *P < 0.05 as determined by unpaired t test.