Author response: GSK3 inhibition rescues growth and telomere dysfunction in dyskeratosis congenita iPSC-derived type II alveolar epithelial cells
Year: 2022
Type: peer-review
Abstract: Article Figures and data Abstract Editor's evaluation Introduction Results Discussion Materials and methods Appendix 1 Appendix 2 Data availability References Decision letter Author response Article and author information Metrics Abstract Dyskeratosis congenita (DC) is a rare genetic disorder characterized by deficiencies in telomere maintenance leading to very short telomeres and the premature onset of certain age-related diseases, including pulmonary fibrosis (PF). PF is thought to derive from epithelial failure, particularly that of type II alveolar epithelial (AT2) cells, which are highly dependent on Wnt signaling during development and adult regeneration. We use human induced pluripotent stem cell-derived AT2 (iAT2) cells to model how short telomeres affect AT2 cells. Cultured DC mutant iAT2 cells accumulate shortened, uncapped telomeres and manifest defects in the growth of alveolospheres, hallmarks of senescence, and apparent defects in Wnt signaling. The GSK3 inhibitor, CHIR99021, which mimics the output of canonical Wnt signaling, enhances telomerase activity and rescues the defects. These findings support further investigation of Wnt agonists as potential therapies for DC-related pathologies. Editor's evaluation This study reports a new cell line model for Dyskeratosis congenita. The authors characterized this model by examining its ability to form organoids and its defects in telomeres. Transcriptomics analysis unveiled defects in Wnt signaling, and treatment with a Wnt agonist could rescue these defects and enhance telomerase activity. Overall, the study is well designed and executed, the data presented are clear and convincing and the conclusions should be of great interest to researchers studying Dyskeratosis congenita and telomere biology. https://doi.org/10.7554/eLife.64430.sa0 Decision letter Reviews on Sciety eLife's review process Introduction Dyskeratosis congenita (DC) is a rare genetic disorder characterized by bone marrow failure, skin abnormalities, elevated risk of certain cancers, and liver and pulmonary fibrosis (PF). These pathologies are caused by abnormally shortened and uncapped telomeres arising from deficiencies in telomere maintenance, typically due to defects in the action of telomerase. Significant progress has been made in treating the bone marrow failure of DC patients, particularly via transplantation, but PF remains a major life-limiting pathology (Agarwal, 2018; Dietz et al., 2011). PF is a subtype of interstitial pneumonia that is chronic and progressive, replacing the normal lace-like alveolar architecture with patchy, hyperproliferative fibrous tissue (Lederer and Martinez, 2018). Current therapies are only modestly effective and do not reverse the underlying fibrosis, and lung transplantation is not always an option (King et al., 2014; Lederer and Martinez, 2018; Richeldi et al., 2014; Valapour et al., 2020). While much of the early work in PF pathogenesis focused on unraveling the contributions of fibroblasts, genetic studies of families with a predisposition to PF argue that defects in alveolar epithelial cells and telomeres are key drivers of disease (Alder et al., 2015; Armanios et al., 2007; Bullard et al., 2005; Cogan et al., 2015; Haschek and Witschi, 1979; Kropski et al., 2015; Maitra et al., 2010; Thomas et al., 2002; Wang et al., 2009). Recent work in mice shows that dysfunctional type II alveolar epithelial (AT2) cells, the putative stem cells of alveoli (Barkauskas et al., 2013), can lead to a progressive chronic fibrotic response similar to that seen in patients (Nureki et al., 2018). Furthermore, many of the same genes which when mutated cause DC have also been linked to familial PF (Alder et al., 2015; Armanios et al., 2007; Cogan et al., 2015; Kropski et al., 2017). In sporadic PF, both age and short telomeres are risk factors, and these risks are linked because age is associated with telomere shortening in the lung, particularly in AT2 cells (Alder et al., 2008; Everaerts et al., 2018). Consistent with a role for telomere dysfunction in driving PF, AT2 cells in sporadic PF express hallmarks of senescence and have shorter telomeres in fibrotic regions than those in non-fibrotic regions (Disayabutr et al., 2016; Kropski et al., 2015; Snetselaar et al., 2017). Additionally, two human Mendelian randomization studies argue that short telomeres are a cause of PF (Duckworth et al., 2020; Telomeres Mendelian Randomization Collaboration et al., 2017). Murine studies also argue that telomere dysfunction and senescence in AT2 cells can drive PF (Naikawadi et al., 2016; Povedano et al., 2015; Yao et al., 2019). Although causality is thus evident, exactly how AT2 cell telomere dysfunction leads to PF is poorly understood. Previous work in our lab using mouse and human induced pluripotent stem (iPS) cell-derived organoid models of DC intestinal defects uncovered a positive feedback loop by which telomere capping and canonical Wnt signaling support one another under normal conditions to maintain the intestinal stem cell niche (Woo et al., 2016; Yang et al., 2017). In the setting of telomere dysfunction, this virtuous cycle becomes vicious: the resulting suppression of Wnt signaling interferes with stem cell function directly, and it also amplifies telomere dysfunction by diminishing Wnt-dependent expression of telomere maintenance factors, including the catalytic subunit of telomerase, TERT, and several of the telomere-protective shelterins. These studies demonstrated that Wnt pathway agonists (including GSK3 inhibitors, which mimic the inhibition of GSK3 by Wnts) can rescue these defects, raising the possibility that Wnt agonism could be of therapeutic benefit in DC. Given how telomere dysfunction in AT2 cells appears to drive PF, we wondered if Wnt agonism might be of benefit in PF. Wnt signaling is important for lung epithelial cell development (Frank et al., 2016; Goss et al., 2009; Li et al., 2002; Li et al., 2005; Maretto et al., 2003; Okubo and Hogan, 2004; Ostrin et al., 2018; Shu et al., 2005) and regeneration of the adult lung in response to injury (Nabhan et al., 2018; Zacharias et al., 2018). On the one hand, there is evidence that Wnts may drive PF; for example, they have been found to be upregulated in patients with PF (Chilosi et al., 2003; Königshoff et al., 2008; Königshoff et al., 2009). On the other hand, when the canonical Wnt transcriptional effector β-catenin is deleted in AT2 cells, mice are sensitized to bleomcyin induced PF (Tanjore et al., 2013). Wnt signaling is complex and context dependent (Wiese et al., 2018), and the exact spatial, temporal, and cell-type specificity of Wnt signaling in PF remains an area of intense investigation. It is difficult to extrapolate from observational pathologic studies of fully developed PF to the potential functional impact of Wnts at earlier stages of the disease, and the large number of interacting cell types in PF lungs also makes it challenging to identify primary drivers in such studies. Furthermore, differences between mouse and human telomere biology together with the generally lower susceptibility of mice to PF make mouse modeling difficult. We therefore generated AT2 cell organoids by directed differentiation of human iPSCs (iPSC-derived AT2 [iAT2] cells) to explore how telomere dysfunction might impact their function (Jacob et al., 2017; Jacob et al., 2019). By comparing iAT2s that are isogenic except for an introduced mutation in the gene most often mutated in DC, X-linked DKC1, we show that mutant iAT2 cells become senescent in concert with telomere shortening and uncapping. iAT2 cells with short, uncapped telomeres exhibit gene expression changes consistent with decreased Wnt signaling, and treatment with GSK3 inhibitors, such as CHIR99021, rescues their growth and telomere dysfunction. These findings raise the possibility that Wnt agonists may be of benefit in rescuing the stem cell and telomere defects of AT2 cells associated with PF in DC patients. Results Engineering a DKC1 mutation into iPS cells To model the AT2 cells from DC patients, we engineered a well-characterized, causal DC mutation in DKC1 (DKC1 A386T) (Agarwal et al., 2010; Batista et al., 2011; Woo et al., 2016) into the BU3 NKX2.1::GFP SFTPC::TdTomato (NGST) human iPS cell line (Jacob et al., 2017). We established an isogenic pair of cell lines: an introduced mutant line and a corresponding unedited wild-type (WT) line (Figure 1—figure supplement 1A-C). Both iPS lines maintained markers of pluripotency and normal karyotypes after the introduction of the DKC1 A386T mutation (Figure 1—figure supplement 1D). Previous work (Agarwal et al., 2010; Batista et al., 2011; Woo et al., 2016) established that iPS cells with the DKC1 A386T mutation exhibit decreased telomerase activity resulting in telomere shortening with passage. We confirmed that telomerase activity was reduced, and telomeres shortened with successive passages, in the BU3 NGST DKC1 A386T iPS cell line when compared to its WT control (Figure 1—figure supplement 2A-C). iAT2 cells with short telomeres fail to form alveolospheres and grow in size We next differentiated these paired iPS cell lines into iAT2 cells using the protocol developed by Jacob et al. (see Figure 1A for differentiation strategy, Figure 1—figure supplement 3A, B for representative sorting strategies). Using iPSCs 35 passages after the introduction of the mutation yielded iAT2s that initially grew in a similar fashion to WT, but which over time developed a growth defect characterized by lower alveolosphere formation efficiency as well as smaller alveolospheres. The phenotype became apparent by 50 days of culture (D50) and was dramatic by D70 (Figure 1A–C). In contrast, using iPSCs only five passages after the introduction of the mutation yielded iAT2s with less dramatic defects in alveolosphere growth and size at D70 (Figure 1—figure supplement 4A-C). These data indicate that the defects observed were due to progressive telomere shortening after introducing the DKC1 mutation, and not the immediate effects of telomerase deficiency (or other potential deficiencies) caused by the DKC1 A386T mutation per se. Figure 1 with 4 supplements see all Download asset Open asset Dyskeratosis congenita induced pluripotent stem cell (iPSC)-derived type II alveolar epithelial cells (iAT2s) fail to form alveolospheres with successive passaging. (A) Differentiation protocol used to probe the effects of the DKC1 A386T mutation on iAT2 cells. D.E., definitive endoderm specification; Ant., anteriorization. (B) Representative images of differentiating wild type and DKC1 A386T mutant bearing iAT2 alveolospheres (scale bars, 100 µm as indicated for iPS and NKX2.1+ progenitors; 1 mm for all alveolosphere images). (C) Quantifications of alveolosphere area and formation efficiency on D70 (n = 4; ** p<0.01, **** p<0.0001, and Student’s t-test). (D) Quantification of the percentage SFTPC+ cells and the number of SFTPC+ cells produced with passage of the iAT2 cells shows DKC1 A386T iAT2 alveolospheres accumulate fewer SFTPC+ cells (n = 4; ** p<0.01, and Student’s t-test). (E) RNA-seq of sorted SFTPC+ iAT2 cells at different passages shows AT2 cell genes are not grossly affected by the DKC1 A386T mutation (n = 4, W = wild type, M = mutant). Figure 1—source data 1 Source Data for Figure 1C-E. Figure 1C-SourceData-FormationEfficiency&OrganoidArea.pzfx – Raw counts of organoid counts normalized to number of cells input to calculate formation efficiency as well as area measurements along with statistical tests. Figure 1D-SourceData-SFTPC%&SFTPCCumYield.pzfx – Percentage SFTPC+ along the differentiation of the induced pluripotent stem cell-derived type II alveolar epithelial cells (iAT2s) from sort flow plots along with cumulative yield of surfactant protein C calculated as the number of SFTPC+ cells produced over the experiment over time. Figure 1E-SourceData-AT2Markers.pzfx – Raw counts from RNA-seq of iAT2s over the differentiation specifically looking at AT2 markers. https://cdn.elifesciences.org/articles/64430/elife-64430-fig1-data1-v2.zip Download elife-64430-fig1-data1-v2.zip Surfactant protein C (SFTPC) is a highly specific marker of AT2 cells (Kalina et al., 1992), and the yield of SFTPC::TdTomato+ (SFTPC+) cells was reduced significantly at D70 in DKC1 mutant cultures, while the percentage of SFTPC+ cells generated at each time point was not different, suggesting that there is a defect in AT2 cell proliferation or survival (Figure 1D). Sorted SFTPC+ cells from iAT2 cell alveolospheres maintained expression of multiple AT2 specific genes suggesting that the introduced mutation did not affect lineage specification (Figure 1E). Thus, DC iPS cells can generate iAT2 cell alveolospheres; however, these alveolospheres lose the capacity to self-renew with successive passaging. DC iAT2 cells derived from iPS cells 35 passages after introduction of the mutation develop hallmarks of senescence at late passage (D70) To better understand the AT2 cell defects, we further compared the WT and mutant iAT2 alveolospheres at different passages. RNA-seq-based gene expression analyses over successive passages of sorted SFTPC+ cells from iAT2 alveolospheres showed decreases in proliferation markers (MKI67 and MCM2) as well as an increase in expression of the cell cycle inhibitor CDKN1A (p21), and these changes were most pronounced in mutant alveolospheres (Figure 2A). Immunofluorescence microscopy based analyses of D70 mutant iAT2 alveolospheres showed an increase in DNA damage marked by 53BP1 foci (Figure 2B), and an increased fraction of cells expressing p21 protein (Figure 2C), but no increase in apoptosis (Figure 2—figure supplement 1A-C). Measuring telomere length using qPCR, DC, and WT iAT2 cells showed no significant change in average telomere length with passage, although average telomere lengths in mutants trended shorter than in WT (Figure 2—figure supplement 2A). However, measuring telomere lengths using TeSLA (Lai et al., 2017), which is more sensitive for the detection of short telomeres than most other techniques, revealed that DC iAT2 cells had a preponderance of short telomeres at D70 (Figure 2E–F). Consistent with this, DC iAT2 alveolospheres showed an increased number of telomere dysfunction induced foci (TIFs), a hallmark of uncapped telomeres (i.e., telomeres that signal DNA damage responses and cell cycle checkpoint arrest Takai et al., 2003; Figure 2D). These findings indicate that the short and uncapped telomeres that accumulate with passage of DC iAT2 cells lead them to senesce. Figure 2 with 2 supplements see all Download asset Open asset Dyskeratosis congenita induced pluripotent stem cell-derived type II alveolar epithelial cells (iAT2s) 35 passages after introduction of the mutation at D70 show hallmarks of senescence. (A) Gene expression profiling of iAT2 cells at D28 and D50 shows no difference between wild type and DKC1 A386T in expression of markers of proliferation and a cell cycle inhibitor, while at D70 cells, there is a significant decrease in MCM2 and MKI67 as well as a significant increase in CDKN1A (p21) (n = 4, **** p<0.0001, DEseq2 pairwise contrast statistics). (B) At D70, DKC1 A386T mutant iAT2 cells have a higher fraction of cells with 53BP1 foci (n = 4, * p<0.05, and Student’s t-test; scale bars, 10 µm; insets highlight cells with 53BP1 foci as noted by the white arrowheads). (C) At D70, DKC1 A386T mutant iAT2s have a higher fraction of cells positive for p21 (n = 4, * p<0.05, and student’s t-test; scale bars, 10 µm). (D) At D70, DKC1 A386T mutant iAT2s have a higher fraction of cells with telomere dysfunction induced foci (TIFs) (n = 4, * p<0.05, and Student’s t-test; scale bars, 10 µm; insets highlight cells with TIFs, each one noted by a white arrowhead). (E) Representative TeSLA of DKC1 A386T iAT2 alveolospheres shows telomeres shorten with passage. (F) Quantification of DKC1 A386T iAT2 cell telomere lengths shows a preponderance of short telomeres appears as the iAT2 cells approach D70, red colored data points highlight telomeres under the 1.6 kb threshold (n = 2, ‘shortest 20%’ reports the 20th percentile of telomere length, in Kb). Figure 2—source data 1 Source data for Figure 2. Figure 2A-SourceData-iAT2-SenescentGeneExpression.pzfx – Raw counts from RNA-seq of induced pluripotent stem cell-derived type II alveolar epithelial cells over the differentiation specifically looking at specific senescence related genes. Figure 2B-SourceData-53BP1PositiveCounts.pzfx – Raw counts of 53BP1 positive cells along with statistics. Figure 2C-SourceData-p21PositiveCounts.pzfx – Raw counts of p21 positive cells along with statistics. Figure 2D-SourceData-TIFPhenotype.pzfx – Raw counts of telomere dysfunction induced foci positive cells along with statistics. Figure 2E,F-SourceData-2020-08-31-TeSLABlotMerged-Cropped.tiff – Uncropped raw image of TeSLA blot along the differentiation showing where the crop was placed for Figure 2E. This is the same blot as used in Figure 4—figure supplement 3B. Figure 2E,F-SourceData-2020-08-31-TeSLABlotMerged.tiff – Uncropped raw image of TeSLA blot along the differentiation showing where the crop was placed for Figure 2E. This is the same blot as used in Figure 4—figure supplement 3B. Figure 2E,F-SourceData-TeSLADKC1A386TAlongDiff.pzfx – Raw counts from TeSLA quant software analysis of cropped blot looking at telomere length along the differentiation along with statistical analysis. https://cdn.elifesciences.org/articles/64430/elife-64430-fig2-data1-v2.zip Download elife-64430-fig2-data1-v2.zip RNA-seq reveals pathways differentially expressed in DC iAT2 cells, including those related to Wnt signaling To further understand changes in the DC iAT2 cells, we more broadly evaluated RNA-seq-based gene expression changes of sorted SFTPC+ iAT2 cells. (Figure 3A). We found very few significantly differentially expressed genes when comparing WT and mutant cells at D28 and D50, but a large number of differentially expressed genes at D70 (Figure 3B), arguing that the gene expression changes seen at D70 are likely driven by uncapped telomeres. Gene set enrichment analyses (GSEA) revealed an upregulation of the DNA damage response, the unfolded protein response (UPR), mitochondrial related functions (oxidative phosphorylation, the respiratory electron chain), a downregulation of hypoxia related signaling, and hedgehog signaling along with other changes (see Supplementary file 1 for a full list). Ingenuity pathway analysis (IPA) revealed similar changes as well as defects in multiple pathways controlled by inflammatory cytokines like IL1β, IL6, IL17, and others (see Supplementary file 2 for the full lists). We found a marked upregulation in DC iAT2 cells of many pathways associated with PF (see Supplementary file 3 for curated list of PF related pathways, see Supplementary files 1 and 2 for the unedited analyses). These included the UPR (Lawson et al., 2008; Mulugeta et al., 2005), thyroid hormone metabolism (Yu et al., 2018), p53 signaling (Shetty et al., 2017), mitochondrial dysfunction and mitophagy (Chung et al., 2019; Yu et al., 2018), and caveolin function (Wang et al., 2006). This analysis also showed an upregulation of non-canonical Wnt signaling (Figure 3C), which correlated with a significant upregulation in WNT5A and WNT11, known non-canonical Wnt ligands (Figure 3D). Furthermore, almost every FZD gene, encoding co-receptors for canonical Wnt signaling, was downregulated in DC iAT2 cells (Figure 3E). Also, GSEA found genes with TCF7 targets in their promoters are downregulated in DC iAT2 cells at D70 (Figure 3F). IPA of master regulators at D70 revealed a decrease in genes controlled by lithium chloride (which can potentiate Wnt signaling by inhibiting GSK3) and TCF7 along with an upregulation of genes usually stimulated by Wnt pathway inhibitors (Figure 3G). GSEA also revealed a significant downregulation of targets of a that we demonstrated many of the Wnt pathway in response to uncapped telomeres (Figure Yang et al., 2017). The genes encoding of the that and maintain normal telomere are targets of the canonical Wnt transcriptional effector and two of and were downregulated in D70 DC iAT2 cells, which may to telomere telomere shortening (Figure Yang et al., 2017). These genes were confirmed to be downregulated by and DC iAT2 cells expressed lower of both and (Figure supplement These data indicate that Wnt signaling in AT2 cells is affected by shortened telomeres and that non-canonical Wnt signaling may be elevated while canonical signaling may be Figure 3 with 1 supplement see all Download asset Open asset RNA-seq of induced pluripotent stem cell-derived type II alveolar epithelial (iAT2) cells reveals a time dependent change in Wnt signaling. (A) to show how cells were for (B) plots at D50, and D70 show how the number of differentially expressed genes at (C) Gene set enrichment analyses (GSEA) at D70 comparing DKC1 A386T iAT2 cells an upregulation of non-canonical Wnt signaling and the cell (D) RNA-seq analysis shows upregulation of WNT5A and WNT11, non-canonical associated with pulmonary fibrosis p<0.05, ** p<0.01, **** p<0.0001, DEseq2 pairwise contrast statistics). (E) RNA-seq analysis shows downregulation of many FZD p<0.05, ** p<0.01, **** p<0.0001, DEseq2 pairwise contrast statistics). (F) GSEA at D70 comparing DKC1 A386T iAT2 cells reveals a downregulation of genes with TCF7 in their Ingenuity pathway analysis reveals master regulators at D70 including downregulation of associated with lithium chloride and and upregulation of associated with multiple Wnt GSEA at D70 comparing DKC1 A386T iAT2 cells reveals a downregulation of genes with and are downregulated in DKC1 A386T iAT2 cells at D70 p<0.05, ** GSK3 inhibitors rescue the growth of DC iAT2 alveolospheres Given our work showing that GSK3 inhibition telomere dysfunction and associated defects in intestinal models of DC (Woo et al., 2016; Yang et al., 2017), we to rescue the DC iAT2 alveolosphere formation defect by treatment with CHIR99021, a GSK3 inhibitor, which thus β-catenin and canonical Wnt genes (Figure the alveolosphere growth defect of iAT2 cells in a dependent fashion (Figure Furthermore, if alveolospheres were to D70 with CHIR99021, this the growth defect from (Figure 4—figure supplement We also another GSK3 inhibitor, which growth of the mutant iAT2 cells (Figure 4—figure supplement These findings that GSK3 inhibition the growth of DC iAT2 alveolospheres. Figure 4 with 3 supplements see all Download asset Open asset rescues growth and telomere defects in (DC) induced pluripotent stem cell-derived type II alveolar epithelial (iAT2) cell alveolospheres. (A) Differentiation protocol used to how growth of DC (B) Representative images of differentiating wild type (WT) and DKC1 A386T mutant bearing cells with of (scale bars, 1 mm for all alveolosphere images). (C) Quantifications of alveolosphere formation efficiency after treatment with of (n = 4, * p<0.05, **** p<0.0001, Student’s t-test). (D) D70 alveolospheres are with 3 CHIR99021, DKC1 A386T mutant iAT2 cells have a lower fraction of cells with data for no are from Figure 2 (n = * p<0.05, Student’s t-test; scale bars, 10 µm). (E) D70 alveolospheres are with 3 CHIR99021, DKC1 A386T mutant iAT2 cells have a lower fraction of p21 positive cells. data for no are from Figure 2 (n = * p<0.05, Student’s t-test; scale bars, 10 µm). (F) D70 alveolospheres are with 3 CHIR99021, DKC1 A386T mutant iAT2 cells have a lower fraction of telomere dysfunction induced foci positive cells. data for no are from Figure 2 (n = * p<0.05, Student’s t-test; scale bars, 10 µm; insets highlight cells with TIFs, each one noted by the white arrowheads). protocol for telomerase activity in iAT2 cells using (n = Figure data 1 Source data for Figure Figure – Raw counts of organoid counts normalized to number of cells input to calculate formation efficiency along with statistical tests. Figure – Raw counts of 53BP1 positive cells after treatment with along with statistics. Figure – Raw counts of p21 positive cells after treatment with along with statistics. Figure – Raw counts of telomere dysfunction induced foci positive cells after treatment with along with – Raw blot of protocol of type II alveolar epithelial (iAT2) cells with showing area that was Figure – Raw blot of of iAT2 cells with Figure – Raw blot of of iAT2 showing area that was Figure – Raw blot of of Figure – Quantifications of in Figure Download senescence markers and in DC iAT2 alveolospheres We how the telomere of DC iAT2 cells showed fewer cells with 53BP1 fewer cells, and fewer cells (Figure TeSLA revealed a increase in average telomere length but no apparent decrease in the of telomeres (Figure 4—figure supplement iAT2 cell telomerase activity was in mutant cells with to similar to those seen in WT cells (Figure these data argue that GSK3 inhibition not only rescues the growth of DC iAT2 cells, but it also rescues telomere defects, most likely upregulation of telomerase activity that could telomeres that are shorter than those that can be by it is also that telomerase is to telomere capping via et al., 2019). of during only days to D70 was to the growth defect (Figure 4—figure supplement consistent with an only increase in telomere length associated with the increased telomerase activity. Discussion We used isogenic human iPS cell lines to generate DC mutant iAT2 cells with shortened telomeres to how telomere dysfunction can affect AT2 cell We found that shortened and uncapped telomeres are associated with a defect in alveolosphere formation by iAT2 cells. This defect is characterized by senescent iAT2 cells that many pathways associated with PF including the mitochondrial and thyroid hormone signaling, and p53 signaling. DC mutant iAT2 cells also canonical Wnt signaling, and consistent with this, GSK3 inhibition rescues telomerase telomere and alveolosphere This a new model to better understand PF pathogenesis and how potential new PF affect AT2 cell function in the context of telomere dysfunction. Wnt signaling is complex and can be into two major β-catenin dependent signaling and β-catenin signaling. These can also be as by studies that show how non-canonical such as can both of Wnt signaling et al., and 2006). These therefore make the reports β-catenin dependent Wnt signaling is of benefit (Tanjore et al., or of in PF et al., et al., 2010; et al., 2011; Königshoff et al., 2008; et al., Given the of the disease both in and time and the context of Wnt signaling, these studies can often only a of the fibrotic Furthermore, there are clear differences between mice and with to telomere and lung biology and 2020; et al., 2011). These highlight the for human models of the spatial, temporal, and cell type specific of Wnt signaling in PF study also
Source: eLife
Authors: Rafael Jesus Fernandez, Zachary JG Gardner, Katherine J Slovik, Derek C Liberti, Katrina N Estep, Wenli Yang, Qijun Chen, Garrett T Santini, Javier V Perez, Sarah Root, Ranvir Bhatia, John W Tobias, Apoorva Babu, Michael P Morley, David B Frank, Edward E Morrisey, Christopher J Lengner, F Brad Johnson
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,500
OpenAlex ID: W4282921560