Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Circadian control of the secretory pathway maintains collagen homeostasis

Abstract

Collagen is the most abundant secreted protein in vertebrates and persists throughout life without renewal. The permanency of collagen networks contrasts with both the continued synthesis of collagen throughout adulthood and the conventional transcriptional/translational homeostatic mechanisms that replace damaged proteins with new copies. Here, we show circadian clock regulation of endoplasmic reticulum-to-plasma membrane procollagen transport by the sequential rhythmic expression of SEC61, TANGO1, PDE4D and VPS33B. The result is nocturnal procollagen synthesis and daytime collagen fibril assembly in mice. Rhythmic collagen degradation by CTSK maintains collagen homeostasis. This circadian cycle of collagen synthesis and degradation affects a pool of newly synthesized collagen, while maintaining the persistent collagen network. Disabling the circadian clock causes abnormal collagen fibrils and collagen accumulation, which are reduced in vitro by the NR1D1 and CRY1/2 agonists SR9009 and KL001, respectively. In conclusion, our study has identified a circadian clock mechanism of protein homeostasis wherein a sacrificial pool of collagen maintains tissue function.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Circadian regulation of the tendon collagen ECM.
Fig. 2: Rhythmic expression of genes regulating collagen trafficking and fibre assembly.
Fig. 3: Circadian clock-regulated PC-I trafficking and collagen fibre assembly in culture.
Fig. 4: Golgi and post-Golgi transport of PC-I is rhythmic.
Fig. 5: Mathematical prediction of PC-I and collagen-I secretion.
Fig. 6: Time-series proteomics analysis of proteins in mouse tendons.
Fig. 7: Dysregulated collagen fibre homeostasis in the absence of a circadian rhythm.
Fig. 8: Circadian clock-deficient tendons have abnormal collagen homeostasis.

Similar content being viewed by others

Data availability

The mouse tail tendon time-series microarray data17 have been deposited to the ArrayExpress repository with the dataset identifier (ArrayExpress accession number E-MTAB-7743). The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository [1] with the dataset identifier PXD013450. All other data supporting the study are available from the corresponding authors on reasonable request. Source data for Figs. 13, 68 and Extended Data Figs. 19 are available online.

Code availability

The code for the secretory pathway model was written in Mathematica (version 11.3) and is available from GitHub at https://github.com/bcalvr/Col1_005.

References

  1. Thul, P. J. et al. A subcellular map of the human proteome. Science 356, eaal3321 (2017).

    Article  PubMed  CAS  Google Scholar 

  2. Parry, D. A. & Craig, A. S. Quantitative electron microscope observations of the collagen fibrils in rat-tail tendon. Biopolymers 16, 1015–1031 (1977).

    Article  CAS  PubMed  Google Scholar 

  3. Wickstrom, S. A. & Fassler, R. Regulation of membrane traffic by integrin signaling. Trends Cell Biol. 21, 266–273 (2011).

    Article  PubMed  CAS  Google Scholar 

  4. Kalson, N. S. et al. A structure-based extracellular matrix expansion mechanism of fibrous tissue growth. eLife 4, e05958 (2015).

  5. Verzijl, N. et al. Effect of collagen turnover on the accumulation of advanced glycation end products. J. Biol. Chem. 275, 39027–39031 (2000).

    Article  CAS  PubMed  Google Scholar 

  6. Thorpe, C. T. et al. Aspartic acid racemization and collagen degradation markers reveal an accumulation of damage in tendon collagen that is enhanced with aging. J. Biol. Chem. 285, 15674–15681 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Heinemeier, K. M., Schjerling, P., Heinemeier, J., Magnusson, S. P. & Kjaer, M. Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb 14C. FASEB J. 27, 2074–2079 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Sivan, S. S. et al. Collagen turnover in normal and degenerate human intervertebral discs as determined by the racemization of aspartic acid. J. Biol. Chem. 283, 8796–8801 (2008).

    Article  CAS  PubMed  Google Scholar 

  9. Dideriksen, K. et al. Effect of acute exercise on patella tendon protein synthesis and gene expression. Springerplus 2, 109 (2013).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  10. Langberg, H., Skovgaard, D., Petersen, L. J., Bulow, J. & Kjaer, M. Type I collagen synthesis and degradation in peritendinous tissue after exercise determined by microdialysis in humans. J. Physiol. 521, 299–306 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Pedersen, B. J., Schlemmer, A., Rosenquist, C., Hassager, C. & Christiansen, C. Circadian rhythm in type I collagen formation in postmenopausal women with and without osteopenia. Osteoporos. Int. 5, 472–477 (1995).

    Article  CAS  PubMed  Google Scholar 

  12. Bollen, A. M., Martin, M. D., Leroux, B. G. & Eyre, D. R. Circadian variation in urinary excretion of bone collagen cross-links. J. Bone Miner. Res. 10, 1885–1890 (1995).

    Article  CAS  PubMed  Google Scholar 

  13. Cermakian, N. & Sassone-Corsi, P. Multilevel regulation of the circadian clock. Nat. Rev. Mol. Cell Biol. 1, 59–67 (2000).

    Article  CAS  PubMed  Google Scholar 

  14. Dudek, M. et al. The chondrocyte clock gene Bmal1 controls cartilage homeostasis and integrity. J. Clin. Invest. 126, 365–376 (2016).

    Article  PubMed  Google Scholar 

  15. Dudek, M. et al. The intervertebral disc contains intrinsic circadian clocks that are regulated by age and cytokines and linked to degeneration. Ann. Rheum. Dis. 76, 576–584 (2017).

    Article  CAS  PubMed  Google Scholar 

  16. Bunger, M. K. et al. Progressive arthropathy in mice with a targeted disruption of the Mop3/Bmal-1 locus. Genesis 41, 122–132 (2005).

    Article  CAS  PubMed  Google Scholar 

  17. Yeung, C. Y. et al. Gremlin-2 is a BMP antagonist that is regulated by the circadian clock. Sci. Rep. 4, 5183 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Sulli, G. et al. Pharmacological activation of REV-ERBs is lethal in cancer and oncogene-induced senescence. Nature 553, 351–355 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Hirota, T. et al. Identification of small molecule activators of cryptochrome. Science 337, 1094–1097 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Sherratt, M. J., Graham, H. K., Kielty, C. M. & Holmes, D. F. Mass-mapping of ECM macromolecules by scanning transmission electron microscopy. Methods Mol. Biol. 522, 151–161 (2009).

    Article  CAS  PubMed  Google Scholar 

  21. Janich, P., Arpat, A. B., Castelo-Szekely, V., Lopes, M. & Gatfield, D. Ribosome profiling reveals the rhythmic liver translatome and circadian clock regulation by upstream open reading frames. Genome Res. 25, 1848–1859 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  22. Meacock, S. L., Greenfield, J. J. & High, S. Protein targeting and translocation at the endoplasmic reticulum membrane—through the eye of a needle? Essays Biochem. 36, 1–13 (2000).

    Article  CAS  PubMed  Google Scholar 

  23. Saito, K. et al. TANGO1 facilitates cargo loading at endoplasmic reticulum exit sites. Cell 136, 891–902 (2009).

    Article  CAS  PubMed  Google Scholar 

  24. Cancino, J. et al. Control systems of membrane transport at the interface between the endoplasmic reticulum and the Golgi. Dev. Cell 30, 280–294 (2014).

    Article  CAS  PubMed  Google Scholar 

  25. Banushi, B. et al. Regulation of post-Golgi LH3 trafficking is essential for collagen homeostasis. Nat. Commun. 7, 12111 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Kreft, L. et al. ConTra v3: a tool to identify transcription factor binding sites across species, update 2017. Nucleic Acids Res. 45, W490–W494 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Bromme, D., Okamoto, K., Wang, B. B. & Biroc, S. Human cathepsin O2, a matrix protein-degrading cysteine protease expressed in osteoclasts. Functional expression of human cathepsin O2 in Spodoptera frugiperda and characterization of the enzyme. J. Biol. Chem. 271, 2126–2132 (1996).

    Article  CAS  PubMed  Google Scholar 

  28. Everts, V. et al. Cathepsin K deficiency in pycnodysostosis results in accumulation of non-digested phagocytosed collagen in fibroblasts. Calcif. Tissue Int. 73, 380–386 (2003).

    Article  CAS  PubMed  Google Scholar 

  29. Stefanovic, L., Longo, L., Zhang, Y. & Stefanovic, B. Characterization of binding of LARP6 to the 5′ stem-loop of collagen mRNAs: implications for synthesis of type I collagen. RNA Biol. 11, 1386–1401 (2014).

    Article  PubMed  Google Scholar 

  30. Park, E. & Rapoport, T. A. Mechanisms of Sec61/SecY-mediated protein translocation across membranes. Annu. Rev. Biophys. 41, 21–40 (2012).

    Article  CAS  PubMed  Google Scholar 

  31. Van den Berg, B. et al. X-ray structure of a protein-conducting channel. Nature 427, 36–44 (2004).

    Article  PubMed  CAS  Google Scholar 

  32. Raote, I. et al. TANGO1 builds a machine for collagen export by recruiting and spatially organizing COPII, tethers and membranes. eLife 7, e32723 (2018).

  33. Ishida, Y. & Nagata, K. Hsp47 as a collagen-specific molecular chaperone. Methods Enzymol. 499, 167–182 (2011).

    Article  CAS  PubMed  Google Scholar 

  34. Schwanhausser, B. et al. Global quantification of mammalian gene expression control. Nature 473, 337–342 (2011).

    Article  PubMed  CAS  Google Scholar 

  35. Humphries, S. M., Lu, Y., Canty, E. G. & Kadler, K. E. Active negative control of collagen fibrillogenesis in vivo. Intracellular cleavage of the type I procollagen propeptides in tendon fibroblasts without intracellular fibrils. J. Biol. Chem. 283, 12129–12135 (2008).

    Article  CAS  PubMed  Google Scholar 

  36. Lin, Y. et al. Sodium laurate, a novel protease- and mass spectrometry-compatible detergent for mass spectrometry-based membrane proteomics. PLoS ONE 8, e59779 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  37. Hoyle, N. P. et al. Circadian actin dynamics drive rhythmic fibroblast mobilization during wound healing. Sci. Transl. Med. 9, eaal2774 (2017).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  38. Hojima, Y., McKenzie, J. A., van der Rest, M. & Prockop, D. J. Type I procollagen N-proteinase from chick embryo tendons. Purification of a new 500-kDa form of the enzyme and identification of the catalytically active polypeptides. J. Biol. Chem. 264, 11336–11345 (1989).

    CAS  PubMed  Google Scholar 

  39. Hojima, Y., van der Rest, M. & Prockop, D. J. Type I procollagen carboxyl-terminal proteinase from chick embryo tendons. Purification and characterization. J. Biol. Chem. 260, 15996–16003 (1985).

    CAS  PubMed  Google Scholar 

  40. Canty, E. G. et al. Coalignment of plasma membrane channels and protrusions (fibripositors) specifies the parallelism of tendon. J. Cell Biol. 165, 553–563 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Choo, K. H., Tan, T. W. & Ranganathan, S. SPdb—a signal peptide database. BMC Bioinform. 6, 249 (2005).

    Article  CAS  Google Scholar 

  42. Vitaterna, M. H. et al. Mutagenesis and mapping of a mouse gene, Clock, essential for circadian behavior. Science 264, 719–725 (1994).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Dierickx, P. et al. SR9009 has REV-ERB-independent effects on cell proliferation and metabolism. Proc. Natl Acad. Sci. USA 116, 12147–12152 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  44. Toyama, B. H. & Hetzer, M. W. Protein homeostasis: live long, won’t prosper. Nat. Rev. Mol. Cell Biol. 14, 55–61 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Szczesny, S. E., Fetchko, K. L., Dodge, G. R. & Elliott, D. M. Evidence that interfibrillar load transfer in tendon is supported by small diameter fibrils and not extrafibrillar tissue components. J. Orthop. Res. 35, 2127–2134 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  46. Hansen, U. & Bruckner, P. Macromolecular specificity of collagen fibrillogenesis: fibrils of collagens I and XI contain a heterotypic alloyed core and a collagen I sheath. J. Biol. Chem. 278, 37352–37359 (2003).

    Article  CAS  PubMed  Google Scholar 

  47. Iozzo, R. V. Matrix proteoglycans: from molecular design to cellular function. Annu. Rev. Biochem. 67, 609–652 (1998).

    Article  CAS  PubMed  Google Scholar 

  48. Wenstrup, R. J. et al. Type V collagen controls the initiation of collagen fibril assembly. J. Biol. Chem. 279, 53331–53337 (2004).

    Article  CAS  PubMed  Google Scholar 

  49. Danielson, K. G. et al. Targeted disruption of decorin leads to abnormal collagen fibril morphology and skin fragility. J. Cell Biol. 136, 729–743 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Benjamini, Y. & Y., H. Controlling the false discovery rate: a practical and powerful approach to multiple testing. J. R. Stat. Soc. B 57, 289–300 (1995).

    Google Scholar 

  51. Blitz, E. et al. Bone ridge patterning during musculoskeletal assembly is mediated through SCX regulation of Bmp4 at the tendon–skeleton junction. Dev. Cell 17, 861–873 (2009).

    Article  PubMed  PubMed Central  Google Scholar 

  52. Storch, K. F. et al. Intrinsic circadian clock of the mammalian retina: importance for retinal processing of visual information. Cell 130, 730–741 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  53. Yoo, S. H. et al. PERIOD2::LUCIFERASE real-time reporting of circadian dynamics reveals persistent circadian oscillations in mouse peripheral tissues. Proc. Natl Acad. Sci. USA 101, 5339–5346 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  54. Yeung, C. Y. et al. Chick tendon fibroblast transcriptome and shape depend on whether the cell has made its own collagen matrix. Sci. Rep. 5, 13555 (2015).

    Article  PubMed  PubMed Central  Google Scholar 

  55. Alvarez, M. B. et al. Immortalization and characterization of osteoblast cell lines generated from wild-type and Nmp4-null mouse bone marrow stromal cells using murine telomerase reverse transcriptase (mTERT). J. Cell. Physiol. 227, 1873–1882 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  56. Livak, K. J. & Schmittgen, T. D. Analysis of relative gene expression data using real-time quantitative PCR and the 2 \(-\Delta\Delta{C_{\mathrm{T}}}\) method. Methods 25, 402–408 (2001).

    Article  CAS  PubMed  Google Scholar 

  57. Starborg, T. et al. Using transmission electron microscopy and 3View to determine collagen fibril size and three-dimensional organization. Nat. Protoc. 8, 1433–1448 (2013).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  58. Kalson, N. S. et al. An experimental model for studying the biomechanics of embryonic tendon: evidence that the development of mechanical properties depends on the actinomyosin machinery. Matrix Biol. 29, 678–689 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Bekker-Jensen, D. B. et al. An optimized shotgun strategy for the rapid generation of comprehensive human proteomes. Cell Syst. 4, 587–599 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  60. Goeminne, L. J., Gevaert, K. & Clement, L. Peptide-level robust ridge regression improves estimation, sensitivity, and specificity in data-dependent quantitative label-free shotgun proteomics. Mol. Cell. Proteomics 15, 657–668 (2016).

    Article  CAS  PubMed  Google Scholar 

  61. Tyanova, S. et al. The Perseus computational platform for comprehensive analysis of (prote)omics data. Nat. Methods 13, 731–740 (2016).

    Article  CAS  PubMed  Google Scholar 

  62. Kammers, K., Cole, R. N., Tiengwe, C. & Ruczinski, I. Detecting significant changes in protein abundance. EuPA Open Proteom. 7, 11–19 (2015).

    Article  CAS  PubMed  Google Scholar 

  63. Smyth, G. K. Linear models and empirical Bayes methods for assessing differential expression in microarray experiments. Stat. Appl. Genet. Mol. Biol. 3, Article3 (2004).

    Article  Google Scholar 

  64. Wu, G., Anafi, R. C., Hughes, M. E., Kornacker, K. & Hogenesch, J. B. MetaCycle: an integrated R package to evaluate periodicity in large scale data. Bioinformatics 32, 3351–3353 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  65. Ihaka, R. & Gentleman, R. R: a language for data analysis and graphics. J. Comput. Graph. Stat. 5, 299–314 (1996).

    Google Scholar 

Download references

Acknowledgements

The research was funded by Wellcome (grant nos. 110126/Z/15/Z and 203128/Z/16/Z to K.E.K.), the MRC (grant no. MR/P010709/1 to Q.J.M.) and Arthritis Research UK (grant no. 20875 to Q.J.M.). V.M. was supported by a studentship from the Sir Richard Stapley Educational Trust. J.S. was funded by a Biotechnology and Biological Sciences Research Council (BBSRC) David Phillips Fellowship (grant no. BB/L024551/1). B.C. is supported by a Wellcome four-year PhD studentship (grant no. 210062/Z/17/Z). H.R.-H. is supported by a University of Manchester four-year PhD studentship. The authors would like to thank R. Schweitzer (Shriners Hospital for Children) for the ScxCre mice; A. Hallworth, R. Hodgkiss and M. Jackson and the University of Manchester Biological Support Facility for assistance with animal welfare and husbandry; and M. Dudek and N. Yang (University of Manchester) for assistance with bioluminescence imaging. The proteomics was performed at the Biological Mass Spectrometry Facility in the Faculty of Biology, Medicine and Health (University of Manchester) with the assistance of S. Warwood and R. O’Cualain, and electron microscopy was performed in the Electron Microscopy Facility, Faculty of Biology, Medicine and Health (University of Manchester).

Author information

Authors and Affiliations

Authors

Contributions

J.C., A.P., C.-Y.C.Y. and R.G. designed and performed experiments, interpreted data and drafted the manuscript. D.F.H., Y.L., B.C. and H.R.-H. designed and performed experiments and interpreted data. V.M., J.S. and A.A. contributed materials and analysis tools. O.J. and T.S. supervised the mathematical aspects of the research. Q.J.M. and K.E.K. conceived the project and supervised the experiments. K.E.K. wrote the manuscript.

Corresponding authors

Correspondence to Qing Jun Meng or Karl E. Kadler.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Electron microscopy and biomechanics.

a, Collagen fibril diameter distributions measured from transverse TEM images of tail tendons sampled through a circadian period. Mice were housed in 12-hour dark/12-hour light cycles. ZT, zeitgeber time (hours into light). Fibrils (n = 1400) were measured for each panel. Black lines show 3-Gaussian fit curves. b, Typical scanning transmission electron microscopy image of fibrils from mechanically disrupted tendon. A set of 50 similar STEM images were acquired for each of 30 tendon samples. Bar, 500 nm. c, Representative mass-per-unit-length distribution measured from scanning transmission electron microscopy images of mechanically disrupted whole tendons. Time point shown is ZT12. The data shown is for n- = 997 fibrils from a single Achilles tendon. All mass-per-unit-length distributions from 30 tendon samples showed a characteristic prominent D1 peak. Percentage of D1 fibrils at all time points over 24 h is shown in Fig. 1e. d, Elastic modulus of Achilles tendon is not time-of-day dependent. Bars show mean ± s.e.m., n = 4 biological replicates, unpaired t-test, p = 0.46. e, Representative hysteresis curves from cyclic loading show the energy loss is greater in tendons taken at ZT15 compared with ZT3, n = 4 biological replicates, n = 5 hysteresis cycles for each displacement rate for each tendon sample. f, Time constants derived from stress–relaxation from an initial 1 N load of Achilles tendon sampled at ZT3 compared to ZT15 (T1, T2 and T3). Bars show mean ± s.e.m., n = 4 biological replicates; the p-values were 0.114, 0.026 and 0.75 for the time constants T1, T2 and T3, respectively. g, Comparison of energy loss values of Achilles tendons at ZT3 versus ZT15 for a 5-fold range of strain rates showing a consistent ~ 40% greater energy loss at ZT15 compared with ZT3. Bars show mean ± s.e.m., n = 4 biological replicates, p-values using the unpaired t-test are 0.27, 0.26, 0.21, 0.004, 0.01 for displacement rates of 1, 2, 3, 4 and 5 mm/min, respectively. See also Statistical Source Extended Data Fig. 1.

Source data

Extended Data Fig. 2 Time-series transcriptomics.

a,b, Expression of core clock genes (Npas2, Per1, Per2, Per3, Arntl, Cry1, and Cry2) mRNA. Transcripts were detected by microarray over a 48-h period. If present, multiple probe sets are shown, n = 2 mice. Metacycle analyses BHQ (Benjamini–Hochberg q-63) values indicated on top right-hand corner. ArrayExpress Accession number E-MTAB-7743 and ref. 17. c, Expression of fibrillar collagen genes in wild-type mouse tail tendon tissue detected by different probe sets in a time series microarray study were not rhythmic, n = 2 mice. Grey shadow indicates subjective night phase. ArrayExpress Accession number E-MTAB-7743 and ref. 17. See also Statistical Source Extended Data Fig. 2.

Source data

Extended Data Fig. 3 Rhythmic ribosome docking.

a, Images of electron microscopy of transverse sections across mouse tendons fibroblasts in vivo showing the endoplasmic reticulum (ER) at different time points, n = 2 biological repeats. Bars 500 nm. b, Quantification of ribosome docking onto ER show differences at ZT2 and ZT15.5 in tendon fibroblasts in vivo, n = 2 biological repeats with 37 (ZT2) and 20 ZT15.5 regions scored across the two samples. Samples were scored by two independent researchers, all samples were blinded (p = 0.00000000034, two-tailed unpaired t-test). The mean and SD for each sample is shown. c, The transcription factor binding site prediction tool Contra v3 http://bioit2.irc.ugent.be/contra/v3 was used to search for binding sites in the promoter and upstream sequences of the genes shown. The default (pragmatic) positional weight matrices (PWMs) score matching stringency in a 500 base promoter region was used. E-box: Ebox, CLOCK/BMAL, Myc, Myc/Max. Cry1/Cry2 binding sites are E-boxes/CLOCK/BMAL and ROR/REV-ERB. D-box: E4BP, NFIL3, ATF2, CEBP. GRE: GRE, NR3C1. ROR: RORA, RORB, RORC. See also Statistical Source Extended Data Fig. 3.

Source data

Extended Data Fig. 4 Rhythmic collagen fibril assembly.

a, MEFs were synchronized and collagen-I deposition was assessed by indirect immunofluorescence every 4 h during 60 h. Representative images from n = 3 for each time point are shown with similar results. Culture of synchronized cells was cultured in the presence of 1 mM DMOG as a control for no collagen secretion. Bars, 10 µm. b, Metacycle analyses values are shown (n = 3 independent experiments; mean ± SD). See also Statistical Source Extended Data Fig. 4.

Source data

Extended Data Fig. 5 Collagen-I intracellular localization.

a, MEFs were synchronized and collagen-I co-localization with GM130 was assessed by indirect immunofluorescence every 4 h during 24 h (up to 15 h post synchronization shown). Arrows point to the Golgi. Bars 10 µm. n = 4 biological repeats. b, Enlarged frames. c, Quantification of the co-localization of collagen-I and GM130 after circadian clock synchronization. d, Quantification of the co-localization of HSP47 and GM130 after circadian clock synchronization. N = 4 independent experiments, mean ± s.e.m. See also Statistical Source Extended Data Fig. 5.

Source data

Extended Data Fig. 6 Secretory pathway protein knockdown.

a, Relative expression of Sec61a1 and Sec61a2 mRNA was reduced in MEFs after CRISPR–Cas9-mediated deletion of both Sec61a1 and Sec61a2 compared to control wild-type MEFs (representative results from n = 3 biological repeats; mean and SD errors are shown *p = 0.0159, p = 0.0143 for Sec61a1 levels; ***p = 0.0007, p = 0.0002 for Sec61a2 levels, two-tailed unpaired t-test). b, Immunofluorescence analysis of collagen-I entry into the ER (detected via the marker calnexin) showed little co-localization of collagen-I and calnexin in Sec61a1 and Sec61a2 KO MEFs compared to wild-type MEFs. c, Relative expression of Mia3 mRNA was reduced in MEFs treated with siRNA targeting Mia3 compared to cells treated with scrambled control siRNA (representative results each showing similar degree of knockdown, n = 3 independent experiments, mean and SD errors are shown; ***p = 0.0004 for KD#2 and #9, two-tailed unpaired t-test). d, Relative expression of Pde4d mRNA was reduced in MEFs treated with siRNA targeting Pde4d compared to cells treated with scrambled control siRNA (n = 3 independent experiments; mean and SD errors shown, ***p = 0.0001, two-tailed unpaired t-test). e, Western blot analysis of MEFs treated with siRNAs targeting Pde4d showed depletion of PDE4D protein (Pde4d KD). Levels of GAPDH protein served as a loading control. f, Relative expression of Vps33b mRNA was significantly reduced in MEFs treated with CRISPR/Cas9n targeting Vps33b compared to control. Controls were wild-type MEFs that underwent electroporation with Cas9 protein but without gRNA (n = 3 biologically independent experiments; mean and SD errors are shown, **p = 0.021, two-tailed t-test). g, Relative expression of Vps33b mRNA in iTTFs after CRISPR/Cas9-mediated deletion of Vps33b (n = 3 biologically independent experiments; mean and SD errors shown, **p = 0.024, two-tailed t-test). h, Western blot analysis of VPS33b protein from Vps33b KO immortalized tail tendon fibroblasts (iTTFs). Vinculin protein served as a loading control. i, TEM of mouse tail tendons prepared in PBS, n = 2. Bar, 1 µm. j, TEM of mouse tail tendons after disruption in SL-DOC and collection by centrifugation, n = 2. Bar, 1 µm. k, Diameter distribution of collagen fibrils in unextracted tendon (untreated) and after extraction by SL-DOC (pellet). l, Hydroxyproline content of dissected tail tendons from mice incubated with SL-DOC. Data are expressed in percentage of total collagen extracted from tendons demonstrating that SL-DOC extracts ~ 18% of total collagen in the tendon (n = 2 animals). See also Statistical Source Extended Data Fig. 6 and Unprocessed Blots Extended Fig. 6.

Source data

Extended Data Fig. 7 Rhythmic procollagen synthesis.

a, The 141 rhythmic proteins were separated into CT1-12 (day) and CT13-24 (night). The numbers of proteins in each group are shown. These two lists were analysed using ENRICHR, the significance of the enrichment of proteins within an ontology is shown on the right and is computed using Fisher’s exact test63. b, Gene ontology terms based on molecular function for each group are shown. c,d, Achilles and tail tendon tissues were harvested at the day phase (ZT3, day) or night phase (ZT15, night) and labelled with 14C-proline for 1 h in the presence of exogenous L-ascorbate. Higher incorporation of 14C was observed in the night phase in both Achilles (n = 6 animals; *p = 0.0423 two-tailed unpaired t-test) and tail tendons (tendons isolated from n = 3 animals; *p = 0.0395 two-tailed unpaired t-test). The central point indicates the mean values for each time point. e, Phosphoimager analysis of 1 h 14C-proline labelling of mouse Achilles tendon. Proteins were extracted into neutral buffer containing NP40 buffer extraction. Higher incorporation of 14C is observed in the night phase. f, Western blot analysis of the samples shown in e. Collagen-I was observed with an anti-collagen-I antibody. e and f are representative blots from two independent experiments consisting of all 8 time points. See also Statistical Source Data Extended Fig. 7 and Unprocessed Blots Extended Fig. 7.

Source data

Extended Data Fig. 8 Rhythmic signal peptide-containing proteins.

a, Peptides in the time-series proteomics analysis (tail tendons from n = 4 independent animals) that contained a signal peptide were identified by overlapping the dataset with the signal peptide database41. The abundance of all signal peptide containing proteins was plotted as a function of circadian time (black). The abundance of the subset of rhythmic proteins (blue) exhibits two peaks at CT7–11 and CT27–31. b, A heat map of the twenty rhythmic signal peptide-containing proteins. See also Statistical Source Extended Data Fig. 8.

Source data

Extended Data Fig. 9 SR9009 affects collagen fibril assembly.

a, Immunofluorescence analysis showed more collagen-I fibres assembled by the fibroblasts of ClockΔ19 mice. N = 3 biological repeats. Bars 10 µm. b, Kill curve of SR9009 showing that concentration of 10 µM (indicated with arrow) is well tolerated by WT and Δ19 fibroblasts. c,d, Luminometry recordings of circadian rhythms of dexamethasone-synchronized fibroblasts isolated from PER2::Luciferase (WT) and ClockΔ19::PER2::Luciferase (Δ19) mice. SR2.5, 2.5 µM SR9009. SR10, 10 µM SR9009. Arrow indicates addition of SR9009. e,f, Immunofluorescence analysis of wild-type and ClockΔ19 fibroblasts either treated with 10 µM SR9009 or mock-treated with dimethylsulfoxide (Ctrl). Blue, DAPI. Red, anti-collagen-I antibody. Number of DAPI-stained nuclei (that is number of cells) and number of fibres were blind scored from randomly-selected regions from n = 3 biological repeats by 3 observers. Number of collagen fibres per cell is shown for control and SR9009-treated fibroblasts. Fold change from qPCR analysis of gene expression is shown for control and SR9009-treated fibroblasts. *p = 0.0127, WT Ctrl vs WT + SR9009; ***p = 0.0005 Δ19Ctrl vs Δ19SR9009. Q-PCR analysis for SR9009-treated WT cells: *p = 0.0476, Sec61a2; *p = 0.0072, Mia3; **p = 0.0042, Serpinh1; *p = 0.0226, Pde4d. Q-PCR analysis for SR9009-treated Δ19 cells: **p = 0.0072, Vps33b; two-tailed paired t-test, n = 4 biological replicates. Bars show s.e.m. See also Statistical Source Data Extended Fig. 9.

Source data

Supplementary information

Supplementary Information

Supplementary Methods

Reporting Summary

Supplementary Video 1

Step-through movie of SBF-SEM of mouse Achilles tendon at 09:00. Bar, 7 µm. Z-depth, 486 µm, images recorded at 9.1 µm intervals to reduce file size.

Supplementary Video 2

Step through movie displaying individual colourised fibrils in small region of mouse tail tendon, showing merging of D1 fibrils onto larger D2 and D3 fibrils. Data gathered from SBF-SEM stack of images. Area shown is 4 × 4 µm, each frame is a longitudinal step of 100 nm through the tendon.

Supplementary Video 3

Step-through movie of SBF-SEM of mouse Achilles tendon at 09:00. Bar, 500 nm. D3 fibril highlighted with a blue line. Filled circles indicate D1 fibrils.

Supplementary Video 4

Step-through movie of SBF-SEM of mouse Achilles tendon showing diameter variability along the length of fibrils and tortuosity of D1 fibrils. Bar, 700 nm. Z-depth, 12.5 µm.

Supplementary Video 5

Step-through animation showing the relative proportion of PC-I in the ER, ER exit sites, Golgi, post-Golgi, plasma membrane and ECM starting at CT0.

Supplementary Video 6

Real-time bioluminescence microscopy of dissected Achilles tendon from wild-type PER2::Luciferase mice during 5 d.

Supplementary Video 7

Real-time bioluminescence microscopy of dissected Achilles tendon from Scx–Cre::Bmal1 lox/lox PER2::Luciferase mice during 5 d. The brightness for the Scx–Cre::Bmal1 lox/lox tendon recording was increased to enable visualization.

Supplementary Table 1

Key resources table

Source data

Source Data Fig. 1

Statistical source data

Source Data Fig. 2

Statistical source data

Source Data Fig. 2

Western blots

Source Data Fig. 3

Statistical source data

Source Data Fig. 3

Western blots

Source Data Fig. 6

Statistical source data

Source Data Fig. 7

Statistical source data

Source Data Fig. 8

Statistical source data

Source Data Extended Data Fig. 1

Statistical source data

Source Data Extended Data Fig. 2

Statistical source data

Source Data Extended Data Fig. 3

Statistical source data

Source Data Extended Data Fig. 4

Statistical source data

Source Data Extended Data Fig. 5

Statistical source data

Source Data Extended Data Fig. 6

Statistical source data

Source Data Extended Data Fig. 6

Western blots

Source Data Extended Data Fig. 7

Statistical source data

Source Data Extended Data Fig. 7

Western blots

Source Data Extended Data Fig. 8

Statistical source data

Source Data Extended Data Fig. 9

Statistical source data

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Chang, J., Garva, R., Pickard, A. et al. Circadian control of the secretory pathway maintains collagen homeostasis. Nat Cell Biol 22, 74–86 (2020). https://doi.org/10.1038/s41556-019-0441-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41556-019-0441-z

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing