Mechanosensitive phosphorylation of NFATC4 at S213/S217 drives fibroblast-to-myofibroblast transition and fibrosis
Safwen Kadri, Laura F. Mattner, Zhen Zeng, Sai Rama Sridatta Prakki, Arun Kumar Verma, Umut Cetin, Christoph H. Mayr, Meshal Ansari, Xin Wei, Sara Asgharpour, Anita A. Wasik, Nikolaus Kneidinger, Mircea-Gabriel Stoleriu, Jürgen Behr, Julien Polleux, Ali Önder Yildirim, Laurens J. De Sadeleer, Wim A. Wuyts, Gerald Burgstaller, Matthias Mann, Martin Mück-Häusl, Herbert B. Schiller
Safwen Kadri, Laura F. Mattner, Zhen Zeng, Sai Rama Sridatta Prakki, Arun Kumar Verma, Umut Cetin, Christoph H. Mayr, Meshal Ansari, Xin Wei, Sara Asgharpour, Anita A. Wasik, Nikolaus Kneidinger, Mircea-Gabriel Stoleriu, Jürgen Behr, Julien Polleux, Ali Önder Yildirim, Laurens J. De Sadeleer, Wim A. Wuyts, Gerald Burgstaller, Matthias Mann, Martin Mück-Häusl, Herbert B. Schiller
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Research Article Cell biology Pulmonology

Mechanosensitive phosphorylation of NFATC4 at S213/S217 drives fibroblast-to-myofibroblast transition and fibrosis

Abstract

Mechanosensitive feedback between tissue stiffness and cellular contractile forces instructs cell identity. To characterize phosphorylation-mediated mechanosensing, we charted the global phosphoproteome dynamics of primary human lung fibroblasts on fibronectin-coated polydimethylsiloxane substrates of defined stiffness. We identified a key signaling threshold at 2–8 kPa, above which cells activated cytoskeletal remodeling, ECM secretion, and transition to a CTHRC1+/ACTA2+ myofibroblast state, accompanied by stiffness-dependent phosphorylation of the transcription factor NFATC4 at S213/S217. In micro-CT staged pulmonary fibrosis tissues, NFATC4 expression increased progressively, colocalizing with CTHRC1 and ACTA2 in myofibroblasts. Transcription factor regulon inference from a multicohort pulmonary fibrosis atlas confirmed elevated NFATC4 activity in disease fibroblasts, revealing a core 119-gene NFATC4-dependent fibrotic program with CTHRC1 as a top target. Phosphomimetic S213D/S217D mutants drove myofibroblast differentiation on soft substrates independently of TGFB, while phospho-dead S213A/S217A mutants blocked differentiation even on stiff matrix with TGFB, establishing the phospho-switch as both necessary and sufficient. Stiff matrix and TGFB converged on this JNK- and calcineurin-dependent switch to amplify the fibrotic response. This positions NFATC4 S213/S217 as a mechanosensitive checkpoint for CTHRC1+ myofibroblast fate and a candidate therapeutic target in multiorgan fibrosis.

Authors

Safwen Kadri, Laura F. Mattner, Zhen Zeng, Sai Rama Sridatta Prakki, Arun Kumar Verma, Umut Cetin, Christoph H. Mayr, Meshal Ansari, Xin Wei, Sara Asgharpour, Anita A. Wasik, Nikolaus Kneidinger, Mircea-Gabriel Stoleriu, Jürgen Behr, Julien Polleux, Ali Önder Yildirim, Laurens J. De Sadeleer, Wim A. Wuyts, Gerald Burgstaller, Matthias Mann, Martin Mück-Häusl, Herbert B. Schiller

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Figure 6

NFATC4 knockdown alters nuclear morphology and positioning on fibronectin micropatterns.

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NFATC4 knockdown alters nuclear morphology and positioning on fibronect...
(A) CCL-151 fibroblasts transfected with siNC or siNFATC4 were seeded on L-shaped fibronectin micropatterns and stained for pMYL9 (active myosin, green), paxillin (PXN; focal adhesions, red), and DAPI (nuclei, blue). siNC nuclei are positioned toward the adhesion-free corner and appear compact, whereas siNFATC4 nuclei are centrally located and more spheroid. Scale bar: 40 μm. (B) Schematic of the morphometric parameters used: cell area, semi-axes, orientation angle (α), circularity, and roundness. (C) Scatterplots of nucleus angle versus nucleus area for CCL-151 (siNC, n = 52; siNFATC4, n = 78) and MLT-018 (siNC, n = 108; siNFATC4, n = 100). (D) Quantification of nucleus area, circularity, and roundness in CCL-151 cells (siNC, n = 52; siNFATC4, n = 78). (E) Nucleus angle comparison between siNC and siNFATC4 in CCL-151 and MLT-018 cells. Statistics: *P < 0.05, ***P < 0.001; paired 2-tailed Student’s t test on per-run means (n = 3). Data are presented as mean ± SD. Box-and-whisker plots show median, IQR, and whiskers to 1.5× IQR. Pink lung icon, CCL-151; black lung icon, MLT-018.