Henry Miller stated that “to relieve a full bladder is one of the great human joys”. Urination is critically important in health and ailments of the lower urinary tract cause high pathological burden. Although there have been advances in understanding the central circuitry in the brain that facilitates urination1,2,3, there is a lack of in-depth mechanistic insight into the process. In addition to central control, micturition reflexes that govern urination are all initiated by peripheral mechanical stimuli such as bladder stretch and urethral flow4. The mechanotransduction molecules and cell types that function as the primary stretch and pressure detectors in the urinary tract mostly remain unknown. Here we identify expression of the mechanosensitive ion channel PIEZO2 in lower urinary tract tissues, where it is required for low-threshold bladder-stretch sensing and urethral micturition reflexes. We show that PIEZO2 acts as a sensor in both the bladder urothelium and innervating sensory neurons. Humans and mice lacking functional PIEZO2 have impaired bladder control, and humans lacking functional PIEZO2 report deficient bladder-filling sensation. This study identifies PIEZO2 as a key mechanosensor in urinary function. These findings set the foundation for future work to identify the interactions between urothelial cells and sensory neurons that control urination.
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The raw data that support the findings of this study are available from the corresponding authors upon reasonable request.
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We thank D. Barucha-Goebel, A. R. Foley and S. Donkervoort for help with the clinical assessments; G. Averion, C. Jones and K. Brooks for experimental assistance; S. Ma and S. Simpson-Dworschak for early work on the project; E. Lacefield for helpful discussions; and the Scripps Histology Core for sample preparation. This work was supported by the Howard Hughes Medical Institute; the NIH grants R35 NS105067 to A.P., F32 DK121494 to K.L.M. and R01 NS108439 to L.S.; and the NIH Intramural Research Program funding from the National Center for Complementary and Integrative Health (A.T.C.) and from the National Institute of Neurological Disorders and Stroke (A.T.C. and C.G.B.).
The authors declare no competing interests.
Peer review information Nature thanks Eric Honoré, Jon Levine and Mark Nelson for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Fig. 1 The bladder urothelium expresses multiple mechanosensitive proteins, and PIEZO2 is not required for sensory neuron pinch responses.
a, FISH in bladder tissue with probes against Krt20 (green) and Piezo1 (white). DAPI in blue. b, FISH in bladder tissue with probes against Krt20 (green) and Tmem63b (white). DAPI in blue. c, Z-projection of the standard deviation of responses from genital pinch in WT and d, Piezo2cKO DRG. e, Quantification of peak responses during pinch shown as percent of baseline (each data point is one cell). n = 3 DRGs, 40 cells for WT, 4 DRGs and 69 cells for Piezo2cKO DRGs.
a, Hoxb8-cre;Ai9 bladder tissue, fixed, frozen and mounted to show tdTomato (red) throughout the tissue, labelled with DAPI (blue). Scale is 100 μm. Expression was evaluated in two mice. b, Example pressure and urethra activity traces from three wild-type males and c, three Hoxb8-cre;Piezo2fl/fl knockout male littermates. d, Heat map of individual bladder contraction events in wild-type and e, knockout male mice, with corresponding urethra activity below in f and g respectively. h, Bladder contraction intervals for males. i, Bladder pressures five seconds before peak contraction for males. Note: 1,200 s was the length of one recording. These dots represent recording periods in which the animal had no successful urination events. j, Total bladder pressure for males and k, sum of urethra activity during bladder contractions. n = 6 males per group. P < 0.0001 for graphs in h, i, j and k, two-sided Student’s t-test with Welch’s correction. l, Body weights from a subset of mice whose bladder weights are shown in Fig. 2t, and m, bladder weights from animals in l, shown as a percentage of body weight. Red horizontal lines indicate means, vertical red bars indicate +/− standard deviation (shown where possible).
a, Upk2-cre;Ai9 bladder tissue fixed, frozen and mounted to show tdTomato (red) throughout the urothelium, labelled with DAPI (blue). Expression was evaluated in two mice. b, Scn10a-cre;Ai9 bladder tissue fixed, frozen and mounted to show tdTomato (red) is not present. Expression was evaluated in two mice. Thin cryosections made neuronal endings difficult to visualize. Scale: 200 μm, applies to a and b. c, Scn10a-cre;Ai9 DRG tissue showing tdTomato (red) in the majority of neurons, and d, a cell backlabelled with CTB-Alexa 488 injected into bladder. e, Merge of c and d, DAPI in blue. 9/9 backlabelled bladder cells analysed from two mice were tdTomato positive. f, Quantification of freshly excised bladder weights from four Upk2-cre;Piezo2fl/fl knockout and wild-type littermates. Age-matched littermates were 10–11 months old, which could account for greater variability. g, Bladder weights from age-matched Scn10a-cre;Piezo2fl/fl knockout mice and wild-type littermates, 7–8 months old. Red lines indicate mean values.
Clinical assessments and notes for all Piezo2-deficient patients interviewed. These represent the answers given by patients during clinician interviews, which sometimes differed from the patient’s own answers to the questionnaire (Table 1). Patient numbers correspond to the numbers shown in Table 1. Not all patients returned the questionnaire.
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Marshall, K.L., Saade, D., Ghitani, N. et al. PIEZO2 in sensory neurons and urothelial cells coordinates urination. Nature 588, 290–295 (2020). https://doi.org/10.1038/s41586-020-2830-7
Nature Reviews Urology (2020)