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Cited by 39Hippo pathway signaling and YAP/TAZLiver physiology and pathologyCellular Mechanics and Interactions

Bile canaliculi remodeling activates YAP via the actin cytoskeleton during liver regeneration

Open access
Meyer, Kirstin, Morales‐Navarrete, Hernan, Seifert, Sarah, Wilsch‐Braeuninger, Michaela, Dahmen, Uta, Tanaka, Elly M, Brusch, Lutz, Kalaidzidis, Yannis +1 more·2020·Molecular Systems Biology
DOI 10.15252/msb.20198985PMC PMC7036714
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Abstract

The mechanisms of organ size control remain poorly understood. A key question is how cells collectively sense the overall status of a tissue. We addressed this problem focusing on mouse liver regeneration. Using digital tissue reconstruction and quantitative image analysis, we found that the apical surface of hepatocytes forming the bile canalicular network expands concomitant with an increase in F‐actin and phospho‐myosin, to compensate an overload of bile acids. These changes are sensed by the Hippo transcriptional co‐activator YAP, which localizes to apical F‐actin‐rich regions and translocates to the nucleus in dependence of the integrity of the actin cytoskeleton. This mechanism tolerates moderate bile acid fluctuations under tissue homeostasis, but activates YAP in response to sustained bile acid overload. Using an integrated biophysical–biochemical model of bile pressure and Hippo signaling, we explained this behavior by the existence of a mechano‐sensory mechanism that activates YAP in a switch‐like manner. We propose that the apical surface of hepatocytes acts as a self‐regulatory mechano‐sensory system that responds to critical levels of bile acids as readout of tissue status.

AI snapshot

Written from the paper’s full text.

TL;DR

During mouse liver regeneration, the bile canalicular network expands and increases apical F-actin/phospho-myosin, and this apical actin-rich compartment recruits and activates YAP in a switch-like manner. The authors propose that hepatocytes use the apical surface as a mechano-sensory system that reads bile acid overload and controls regenerative growth.

Key findings

  • After partial hepatectomy (PH), bile canaliculi (BC) dilate and branch early: BC diameter increased on average 21% at 1.5 days post-PH (up to 27% in zone 11; untreated 1.96–2.27 μm vs. 2.40–2.61 μm at 1.5 days), and remained 11% larger on average at 5 days. EM at 1.8 days post-PH showed BC perimeter and total membrane length increased 1.5-fold and 1.4-fold, respectively.
  • Apical acto-myosin changes accompany BC expansion: after PH, apical pMLC rose early and stayed elevated by about 70% until ~2.8 days, while apical F-actin showed a maximum increase of 17 ± 10% at 1.5 days versus untreated mice. Sham operation alone reduced apical F-actin by up to 37 ± 9%.
  • YAP activation correlates with BC remodeling: nuclear YAP increased specifically in regenerating livers from 0.5 day post-PH and ceased with the proliferative wave at ~3–4 days; nuclear YAP increased 2.5-fold at 2 days post-PH by fractionation. YAP was enriched apically, with immunogold density 4.2-fold higher in apical than basolateral regions.
  • Bile acid and actin perturbations modulate YAP: 200 μM deoxycholic acid increased nuclear YAP 1.7-fold and pMLC 1.57-fold in primary hepatocytes; the Rho kinase inhibitor Y27 reduced the DCA effect by 47%. In vivo, fasudil dilated BC diameter by 15.6% (zone 18) after PH and reduced nuclear YAP during regeneration by up to 52%. A biophysical-biochemical model predicted a ~2-fold increase in apical tension, correlated with pMLC (r = 0.94), and a switch-like YAP response above ~1.75-fold relative mechanical stimulus.

Methods

  • Mouse models: 8–12-week-old male C57BL/6JOlaHsd mice underwent partial hepatectomy (PH), sham operation, bile duct ligation (BDL), hepatocyte-specific mosaic YAP knockout, or fasudil/saline treatment; livers were analyzed at time points from 0.5 to 7 days.
  • Imaging and biochemical assays: high-resolution confocal microscopy with 3D BC reconstruction, immunofluorescence for CD13, F-actin, pMLC, YAP, and PCNA; electron microscopy and correlative light EM; subcellular fractionation; Western blot; YAP co-immunoprecipitation with mass spectrometry; primary mouse hepatocyte sandwich cultures with DCA and actin inhibitors; qPCR for YAP target genes.
  • Modeling: a biophysical model inferred apical cortical tension from measured BC diameter, coupled to a biochemical model of YAP regulation with 16 parameters, of which 9 were estimated by fitting quasi-steady-state solutions to 120 nuclear and total YAP data points.

Limitations

  • The paper states that the precise molecular mechanisms underlying the actin cytoskeleton’s mechano-sensing readout by YAP are unclear, and that other mechanisms/pathways sensing apical membrane size, membrane tension, cell–cell junction integrity, or the actin cytoskeleton are not excluded; it also notes that it is technically impossible to measure pressure within the BC directly.
  • The paper states that the absolute requirement of the Hippo pathway in liver regeneration is unclear, and that YAP has pleiotropic functions beyond proliferation, so downstream links remain to be resolved.
  • Evident from the text: the mechanical stimulus is inferred from a model rather than directly measured, and some in vitro inhibitor effects on YAP target genes were discordant with nuclear YAP translocation (e.g., latrunculin A increased nuclear YAP but reduced target gene expression).

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.15252/msb.20198985

Cites

65 of 65 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

5 of 32 cited sources checked · 5 supported · 0 flagged

  • Findingown data

    Deoxycholic acid is sufficient to stimulate YAP nuclear translocation, producing a 1.7-fold increase compared with DMSO control cells.

    “DCA was sufficient to stimulate YAP nuclear translocation (1.7‐fold increase as compared to DMSO control cells, Fig 5B), consistent with earlier observations (Anakk et al, 2013).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Anakk et al, 2013 source
  • Premisecitation

    Bile pressure forms a gradient within the lobule varying ~30-fold from the CV to the PV area.

    “Bile pressure forms a gradient within the lobule varying ~ 30‐fold from the CV to the PV area (Meyer et al, 2017).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Meyer et al, 2017 source
  • Findingown data

    Expansion of the bile canaliculi network during regeneration is associated with a concomitant increase in apical F-actin and phospho-myosin light chain levels, signs of increased acto-myosin contractility.

    “Overall, the expansion of the BC network during regeneration is associated with a concomitant increase in apical F‐actin and pMLC levels, i.e., signs of increased acto‐myosin contractility.”
    Quote in the paperSubstantial claim
  • Findingown data

    Electron microscopy confirmed bile canaliculi expansion after partial hepatectomy.

    “The EM analysis (Fig 1C) confirmed the BC expansion (Fig 1A).”
    Quote in the paperSubstantial claim
  • Findingcitation

    The observed structural changes of the bile canaliculi network precede the reported temporal profile of hepatocyte proliferation, which starts at 1.5 days post-partial hepatectomy and peaks at 2 days.

    “Interestingly, the observed structural changes preceded the reported temporal profile of hepatocyte proliferation, which starts at 1.5 days post‐PH and peaks at 2 days (Zou et al, 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zou et al, 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims. 43
  • Classified as probably not a substantial claim. 14

  • May combine two claims.

    Premisecitation

    Fasudil efficiently inhibits bile canaliculi contractility and bile flow in vivo.

    “We have previously shown that Fasudil efficiently inhibits BC contractility and bile flow in vivo (Meyer et al, 2017).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Meyer et al, 2017 source

  • May combine two claims.

    Premisecitation

    Bile flow through BC is driven by both the osmotic pressure of actively pumped bile salts and osmolytes, and contractility of BC.

    “Bile flow through BC is driven by both the osmotic pressure of actively pumped bile salts and osmolytes, and contractility of BC (Watanabe et al, 2014; Meyer et al, 2017).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Watanabe et al, 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Meyer et al, 2017 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    BA are also regulators of the Hippo pathway, acting via the induction of the scaffold protein IQGAP1.

    “Besides signal messengers, BA are also regulators of the Hippo pathway, acting via the induction of the scaffold protein IQGAP1 (Anakk et al, 2013).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Anakk et al, 2013 source

  • May combine two claims.

    Findingown data

    Nuclear YAP starts as an immediate response to liver resection as early as 0.5 day post-partial hepatectomy, ceases with the proliferative wave at about 3-4 days, and occurs throughout the entire central vein-portal vein axis.

    “It started as an immediate response to liver resection, as early as 0.5 day post‐PH, ceased with the proliferative wave at about 3–4 days (Fig 3C), and occurred throughout the entire CV‐PV axis (Fig 3D).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    During regeneration, the major fraction of YAP remains cytoplasmic, but YAP is also detectable in nuclei of proliferating hepatocytes.

    “The major fraction of YAP was still cytoplasmic, but, in addition, it was also detectable in nuclei of proliferating hepatocytes (Fig 3B, Appendix Fig S4B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    In livers of untreated mice, YAP is highly expressed in cholangiocytes but at low levels in hepatocytes, where it is primarily cytosolic.

    “Consistent with earlier reports (Yimlamai et al, 1999), YAP was highly expressed in cholangiocytes but at low levels in hepatocytes in the livers of untreated mice (Fig 3A) where it was primarily cytosolic, as expected for non‐proliferating cells (LaQuaglia et al, 2009).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Yimlamai et al, 1999

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites LaQuaglia et al, 2009

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    The bile canaliculi network dilates and branches as early as 0.8 day post-partial hepatectomy throughout the entire central vein-portal vein axis and reverses to normal at about 3-5 days post-partial hepatectomy.

    “The BC network dilated and branched as early as 0.8 day post‐PH (Fig 1A) throughout the entire CV‐PV axis and reversed to normal at ~ 3–5 days post‐PH.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Upon partial hepatectomy, apical F-actin intensity is higher than after sham operation and fluctuates at baseline levels compared with untreated mice, with a maximum increase of 17 ± 10% at 1.5 days.

    “However, upon PH, the F‐actin intensity was higher than after sham operation and fluctuated at baseline levels as compared to untreated mice, with a maximum increase of 17 ± 10% (mean ± s.e.m) at 1.5 days (Fig 2B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Bile canaliculi diameter increases by up to 27% in zone 11 and on average by 21% throughout the entire central vein-portal vein axis at 1.5 days after partial hepatectomy compared with untreated liver.

    “Spatial quantification revealed an increase in BC diameter by up to 27% (zone 11) and on average by 21% throughout the entire CV‐PV axis at 1.5 days after PH as compared to the untreated liver (1.96–2.27 μm in untreated liver; 2.40–2.61 μm at 1.5 days post‐PH; Fig 1B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    After bile duct ligation, bile canaliculi expansion occurs already at 1 day post-ligation throughout the entire central vein-portal vein axis, preceding hepatocyte proliferation.

    “As in regeneration, the expansion occurred already at 1 day post‐BDL throughout the entire CV‐PV axis, preceding hepatocyte proliferation (Georgiev et al, 2015).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Georgiev et al, 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    After partial hepatectomy, bile canaliculi lack the typical smooth and regular appearance and acquire a rough surface texture.

    “In addition, the BC lacked the typical smooth and regular appearance at this resolution and acquired a rough surface texture (Fig 1A, compare BC in PV area of untreated vs. 1.5 days post‐PH).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    At 5 days post-partial hepatectomy, bile canaliculi diameter is still increased, but only by 11% on average.

    “At 5 days post‐PH, the BC diameter was still increased, but only by 11% on average (BC diameter at 5 days post‐PH, 2.14–2.51 μm).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Both bile canaliculi perimeter and total membrane length increase to a similar extent, 1.5-fold and 1.4-fold respectively, after partial hepatectomy.

    “Both BC perimeter and total membrane length increased to a similar extent, 1.5 and 1.4‐fold, respectively (Fig 1D and E).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Comparison of inferred cortical tension and experimentally measured apical pMLC levels shows a high correlation (Pearson r = 0.94), supporting the predictive power of the model.

    “Comparison of the inferred cortical tension and our experimentally measured apical pMLC levels shows a high correlation (Pearson correlation r = 0.94, Appendix Fig S9B), supporting the predictive power of the model.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cytochalasin D, latrunculin A, and SMIFH2 induce nuclear YAP translocation, mimicking the effect of deoxycholic acid, whereas other tested drugs are either ineffective or inhibitory (Y27).

    “Cytochalasin D, latrunculin A, and SMIFH2 induced nuclear YAP translocation (Fig 5E), mimicking the effect of DCA, whereas the other drugs were either ineffective or inhibitory (Y27).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Fasudil strongly dilates bile canaliculi diameter in mice after partial hepatectomy (15.6%, zone 18) and moderately in the liver of sham-operated mice (9.3%, zone 15).

    “Spatial analysis showed that fasudil strongly dilated the BC diameter in mice after PH (15.6%, zone 18) and moderately in the liver of sham OP mice (9.3%, zone 15; Fig 6B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The density of immunogold particles is on average 4.2-fold higher in the apical than the basolateral region, demonstrating that YAP is enriched at the apical compartment during regeneration.

    “The density of immunogold particles was on average 4.2‐fold higher in the apical than the basolateral region (Appendix Fig S5C), demonstrating that YAP is enriched at the apical compartment during regeneration.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Deoxycholic acid induces strong dilation of bile canaliculi and up-regulation of YAP, as observed during regeneration in vivo.

    “DCA also induced a strong dilation of BC (Fig 5A, compare Control vs. DCA) and up‐regulation of YAP (Appendix Fig S7A), as observed during regeneration in vivo (Appendix Fig S4C).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Y27 and cytochalasin D have opposite effects on YAP target genes, decreasing and increasing YAP target gene expression, respectively.

    “Consistently, Y27 and cytochalasin D have opposite effects, decreasing and increasing YAP target genes, respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Both Y27 and Fasudil reduce phospho-myosin light chain levels compared with the control.

    “In contrast, both Y27 and Fasudil reduced pMLC levels in comparison with the control.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Sham operation alone causes a small increase in nuclear YAP levels that is also reduced by fasudil.

    “Note that the sham operation alone caused a small increase in nuclear YAP levels that was also reduced by fasudil (Fig 6D, green lines).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Apical YAP localization is detectable throughout the central vein-portal vein axis, both in PCNA-positive and PCNA-negative hepatocytes, and is specific to regenerating liver compared with untreated and sham-operated mice.

    “The apical localization was detectable throughout the CV‐PV axis, both in PCNA‐positive and in PCNA‐negative hepatocytes, and was specific to regenerating liver as compared to untreated and sham‐operated mice (Appendix Fig S5A).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Incubation of hepatocytes with the Rho kinase inhibitor Y-27632 potently reduces phospho-myosin light chain levels and blocks the increase in nuclear YAP, reducing the effect of deoxycholic acid by 47%.

    “Incubation of hepatocytes with the Rho kinase inhibitor Y‐27632 (Y27) potently reduced pMLC levels (Fig 5C, Appendix Fig S7B) and blocked the increase in nuclear YAP, reducing the effect of DCA by 47% (Fig 5A and B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    During regeneration, restoration of the liver-to-body weight ratio re-establishes metabolic homeostasis, the structure of the BC network reverts to normal, and YAP returns to its physiological state (cytoplasmic localization).

    “During regeneration, the restoration of the liver‐to‐body weight ratio also re‐establishes the metabolic homeostasis, the structure of the BC network reverts to normal, and YAP returns to its physiological state (cytoplasmic localization).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Liver resection induces structural and functional changes of the BC network, including expansion of the apical surface of hepatocytes and increase in acto-myosin contractility.

    “We demonstrate that liver resection induces structural and functional changes of the BC network, including expansion of the apical surface of hepatocytes and increase in acto‐myosin contractility.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Tissue resection by partial hepatectomy induces a BA overload which elevates osmotic pressure and cortical tension of bile canaliculi, and concomitant changes of apical acto-myosin properties recruit YAP to the apical cortex where it is activated for nuclear translocation.

    “Tissue resection by partial hepatectomy induces a BA overload which elevates osmotic pressure and cortical tension of bile canaliculi. Concomitant changes of apical acto‐myosin properties recruit YAP to the apical cortex where it is activated for nuclear translocation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Latrunculin A reduces YAP target gene expression despite increasing nuclear YAP levels, indicating that nuclear translocation is not sufficient for target gene expression in this system.

    “However, latrunculin A reduced YAP target gene expression despite increasing nuclear YAP levels, indicating that nuclear translocation is not sufficient for target gene expression in this system.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The stimulatory effect of deoxycholic acid on YAP nuclear translocation requires the acto-myosin system, but the partial effect of Y-27632 argues that there may also be an actin-independent component in bile acid-induced YAP activation.

    “These results suggest that the stimulatory effect of DCA requires the acto‐myosin system, but the partial effect of Y27 argues that there may be an actin‐independent component involved in BA‐induced YAP activation as well (e.g., by sensing osmotic pressure, membrane area/tension, cell–cell junctions).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The mechanism tolerates moderate bile acid fluctuations under tissue homeostasis but activates YAP in response to sustained bile acid overload.

    “This mechanism tolerates moderate bile acid fluctuations under tissue homeostasis, but activates YAP in response to sustained bile acid overload.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    To account for spatial heterogeneities of proliferation within the liver lobule, the entire central vein-portal vein axis was imaged at 17 time points during regeneration and upon sham surgery.

    “To account for previously reported spatial heterogeneities of proliferation within the liver lobule (Wu et al, 2015), we imaged the entire CV‐PV axis at 17 time points (0.5–7 days) during regeneration (Fig 3A and B) and upon sham surgery (Appendix Fig S4A and B).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Wu et al, 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationown data

    The in vitro collagen sandwich hepatocyte system recapitulates some properties of hepatocytes in the regenerating liver and is suitable for studying YAP regulation.

    “Thus, the in vitro system recapitulates some of the properties of hepatocytes in the regenerating liver and, thus, proves suitable for studying YAP regulation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Primary mouse hepatocytes cultured in collagen sandwich re-polarize forming bile canaliculi in vitro and exhibit a cholestatic-like phenotype.

    “When cultured in collagen sandwich, these cells re‐polarize forming BC in vitro (Zeigerer et al, 2012) and exhibit a cholestatic‐like phenotype (Rippin et al, 2016), mimicking aspects of the metabolic state of the regenerative liver.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Zeigerer et al, 2012

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Rippin et al, 2016

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Upon PH without removal of the gall bladder, the total bile salt pool in the body is only marginally reduced, since intra-hepatic BA account for just 2-4% of the total pool.

    “Upon PH without removal of the gall bladder, the total bile salt pool in the body is only marginally reduced, since intra‐hepatic BA account for just 2–4% of the total pool (Setchell et al, 2008).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Setchell et al, 2008

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationcitation

    The liver remnant needs to transport the full bile salt pool through a reduced BC network, leading to increased bile salt flux per liver weight and consequently increased osmotic pressure, fluid inflow, fluid pressure, dilation of the apical membrane, and acto-myosin tension in the BC.

    “Therefore, the liver remnant needs to transport the full bile salt pool through a reduced BC network, leading to an increased bile salt flux per liver weight (Vos et al, 1997) and, consequently, increased osmotic pressure, fluid inflow, increased fluid pressure, dilation of the apical membrane, and acto‐myosin tension in the BC.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Vos et al, 1997

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Such variation in bile pressure needs to be balanced by the tension of the acto-myosin system.

    “Such variation needs to be balanced by the tension of the acto‐myosin system.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    MAL/SRF transcription factors are suitable candidates for mechano-sensing because they respond to actin dynamics and regulate YAP/TAZ target genes.

    “For example, the MAL/SRF transcription factors are also suitable candidates since they respond to actin dynamics and regulate YAP/TAZ target genes (Foster et al, 2007).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Foster et al, 2007

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Peptide identifications were accepted if they could be established at >95.0% probability, protein identifications at greater than 99.0%, and contained at least two identified peptides.

    “Peptide identifications were accepted if they could be established at > 95.0% probability—protein identifications at greater than 99.0%—and contained at least two identified peptides.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    The organization of all hepatocytes connected via the BC permits communication of global tissue properties, e.g., metabolic status, to each individual cell within the lobule, to control cell behavior collectively.

    “Such organization permits the communication of global tissue properties, e.g., metabolic status, to each individual cell within the lobule, to control cell behavior collectively.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: All hepatocytes are connected via the BC, bridging the sub-cellular to the tissue level.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Elevated BA levels promote hepatocyte proliferation, whereas deprivation of BA results in a regenerative delay.

    “Whereas elevated BA levels promote hepatocyte proliferation, deprivation of BA results in a regenerative delay (Huang et al, 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Huang et al, 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    In total, data from two independent co-IP experiments were analyzed, and unspecific proteins detected in IgG control conditions were removed from the protein list.

    “In total, data from two independent co‐IP experiments were analyzed. Unspecific proteins detected in IgG control conditions were removed from the protein list.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Key for the signaling function of the BC network is the dynamic nature of the apical plasma membrane and its associated actin cytoskeleton of hepatocytes, which can promptly respond to metabolic changes.

    “Key for the signaling function of the BC network is the dynamic nature of the apical plasma membrane and its associated actin cytoskeleton of hepatocytes, which can promptly respond to metabolic changes.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The function of BA as regulators of liver regeneration has been demonstrated early on and mainly attributed to their signaling function via nuclear receptors.

    “The function of BA as regulators of liver regeneration has been demonstrated early on and mainly attributed to their signaling function via nuclear receptors (Huang et al, 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Huang et al, 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A wide array of apical actin interacting, polarity, and cell junction-associated proteins have been reported to regulate the Hippo pathway.

    “A wide array of apical actin interacting, polarity, and cell junction‐associated proteins have already been reported to regulate the Hippo pathway (Chen et al, 1980; Oka et al, 2015).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Chen et al, 1980

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Oka et al, 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    For quantification of YAP protein in liver tissue fractions, YAP signal was normalized to the fraction marker (GAPDH, histone H3, TRF2) and each condition (sham, PH) was normalized to the untreated control.

    “For quantification of YAP protein in liver tissue fractions, YAP signal was normalized to the fraction marker (GAPDH, histone H3, TRF2) and each condition (sham, PH) was normalized to the untreated control.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    Our reported YAP interactors, including actin and cell-cell junction-associated proteins, provide a list of candidate molecular players potentially involved.

    “Our reported YAP interactors, including actin and cell–cell junction‐associated proteins, provides a list of candidate molecular players potentially involved.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Changes of pressure need to be sensed, evoking the need for a mechano-sensory system.

    “This implies that changes of pressure need to be sensed, evoking the need for a mechano‐sensory system.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The rate of water flow into BC is subject to complex regulation in response to BA transport and aquaporin-mediated permeability, leading to changes in osmotic pressure and bile flow.

    “The rate of water flow into BC is subjected to a complex regulation in response to BA transport but also aquaporin‐mediated permeability, leading to changes in osmotic pressure and bile flow (Marinelli et al, 2016).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Marinelli et al, 2016

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    The BC network represents a self-regulatory mechano-sensory system that adapts to the overall metabolic demand of the body and acts as readout of tissue status.

    “Thus, the BC network represents a self‐regulatory mechano‐sensory system that adapts to the overall metabolic demand of the body and acts as readout of tissue status.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Fluctuations of BA concentrations in the physiological range could be compensated by the metabolic activity of hepatocytes, whereas large and sustained changes, as after PH, trigger the Hippo pathway in a switch-like manner to induce regeneration.

    “This means that fluctuations of BA concentrations in the physiological range could be compensated by the metabolic activity of hepatocytes, whereas large and sustained changes, as after PH, trigger the Hippo pathway in a switch‐like manner to induce regeneration.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    These changes occur as a compensatory response to BA overload induced by tissue resection and are sensed by YAP, which is enriched at the apical domain of hepatocytes and translocates to the nucleus dependent on the integrity of the actin cytoskeleton.

    “These changes occur as a compensatory response to BA overload induced by tissue resection and are sensed by YAP, which is enriched at the apical domain of hepatocytes and translocates to the nucleus dependent on the integrity of the actin cytoskeleton.”
    Quote in the paperSubstantial claim
50 of 50

  • The paper relies on this without support.

    Moderate fluctuations of bile acid concentrations do not result in YAP activation.

    “In contrast, moderate fluctuations of BA concentrations, resulting, e.g., from circadian rhythm or diet (Ma et al, 1996; Eggink et al, 2014), can be buffered by the metabolic activity of hepatocytes and do not result in YAP activation.”

  • The paper relies on this without support.

    It is currently technically impossible to measure pressure within the BC.

    “It is currently technically impossible to measure pressure within the BC.”

  • The authors state this as an assumption.

    The considered reactions follow simple mass action and Michaelis–Menten kinetics.

    “Assuming simple mass action and Michaelis–Menten kinetics for the considered reactions (see Fig 7A), the model has 16 parameters.”

  • The paper relies on this without support.

    All hepatocytes are connected via the BC, bridging the sub-cellular to the tissue level.

    “A remarkable feature of liver tissue organization is that all hepatocytes are connected via the BC, bridging the sub‐cellular to the tissue level.”
4 of 4

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Fasudil administration routes disagree

    Major

    The Results describe fasudil as given by intraperitoneal injection, whereas the Methods specify intravenous administration for the same post-PH or sham experiment.

  • BC diameter is described as normal by day 5 but remains elevated

    Minor

    The text says BC network geometry reversed to normal by approximately 3-5 days after PH, but it also reports that BC diameter was still 11% higher at day 5.

2 of 2

Cites

Flagged first, then by citations

1 of the 66 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Related

Authors
Meyer, K., Morales‐Navarrete, H., Seifert, S., Wilsch‐Braeuninger, M., Dahmen, U., Tanaka, E. M., Brusch, L., Kalaidzidis, Y., & Zerial, M.
Affiliations
  • Max Planck Institute of Molecular Cell Biology and Genetics (DE)
  • Jena University Hospital (DE)
  • Research Institute of Molecular Pathology (AT)
  • Center for Information Services and High Performance Computing (DE)
  • Lomonosov Moscow State University (RU)
Corresponding author
Zerial, Marino
ORCID
Venue
Molecular Systems Biology
Publisher
Springer Science and Business Media LLC
Published
2020-02-01
Volume
16
Issue
2
Pages
e8985-e8985
ISSN
1744-4292 (ISSN-L)
DOI
10.15252/msb.20198985
PMC
PMC7036714
OpenAlex
W3008789663
Semantic Scholar
50cda9f832a00438f9eb41c2d2fd6f592f411ff0
Cited by
39
References
66
Citations by year
2026: 1 · 2025: 5 · 2024: 6 · 2023: 7 · 2022: 7 · 2021: 9 · 2020: 4
FWCI
2.86
Type
journal article
Language
en
Open access
Licence
Locations
  • Molecular Systems Biology (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • Bundesministerium für Bildung und Forschung (315757, 031L0038, 031L008A, 031L0044)
  • H2020 European Research Council (695646)
  • Max-Planck-Gesellschaft
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Hippo pathway signaling and YAP/TAZ
  • Health Sciences › Medicine › Hepatology › Liver physiology and pathology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular Mechanics and Interactions
Keywords
liver regeneration, bile canaliculi, YAP, Hippo signaling pathway, actin cytoskeleton, F-actin, mechanosensing, switch-like response
MeSH terms
YAP-Signaling Proteins, Actins, Animals, Bile Acids and Salts, Bile Canaliculi, Cell Nucleus, Cells, Cultured, Liver Regeneration, Male, Actin Cytoskeleton, Myosins, Organ Size, Cell Cycle Proteins, Protein Transport, Hepatocytes, Mechanotransduction, Cellular, Adaptor Proteins, Signal Transducing, Systems Biology, Mice

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-23.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-23.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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