Critical role of Lkb1 in the maintenance of alveolar macrophage self-renewal and immune homeostasis
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE167349 | GEO | 2021/03/01
REPOSITORIES: GEO
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Project description:The rapid transit from hypoxia to normoxia in the lung that follows the first breath in newborn mice coincides with alveolar macrophage (AM) differentiation. However, whether sensing of oxygen affects AM maturation and function has not been previously explored. We have generated mice whose AMs show a deficient ability to sense oxygen after birth by deleting Vhl, a negative regulator of HIF transcription factors, in the CD11c compartment (CD11c∆Vhl mice). VHL-deficient AMs show an immature-like phenotype and an impaired self-renewal capacity in vivo that persists upon culture ex vivo. VHL-deficient phenotype is intrinsic in AMs derived from monocyte precursors in mixed bone marrow chimeras. Moreover, unlike control Vhlfl/fl, AMs from CD11c∆Vhl mice do not revert pulmonary alveolar proteinosis when transplanted into Csf2rb-/- mice, demonstrating that VHL contributes to AM-mediated surfactant clearance. Thus, our results suggest that optimal AM terminal differentiation, self-renewal, and homeostatic function requires their oxygen sensing capacity.
2018-06-27 | GSE108975 | GEO
Project description:Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, irreversible, and lethal lung disease. The initiation of IPF involves microinjuries to and/or dysfunction of the alveolar epithelium, but factors that determine fibrosis progression or normal tissue repair are largely unknown. We previously demonstrated that autophagy inhibition-mediated epithelial-mesenchymal transition (EMT) in human alveolar epithelial type II (ATII) cells augments local myofibroblast differentiation in pulmonary fibrosis by paracrine signalling. Here, we report that liver kinase B1 (LKB1) inactivation in ATII cells induces autophagy inhibition and EMT as a consequence. In IPF lungs, this is caused by a downregulation of CAB39L, a key subunit within the LKB1 complex. 3D co-cultures of ATII cells and lung fibroblast MRC5 coupled with RNA sequencing (RNA-seq) confirmed that paracrine signalling between LKB1-depleted ATII cells and fibroblasts augmented myofibroblast differentiation. Together these data suggest that reduced autophagy caused by LKB1 inhibition can induce EMT in ATII cells and contribute to fibrosis via aberrant epithelial–fibroblast crosstalk.
2023-08-09 | GSE205969 | GEO
Project description:LKB1 is among the most frequently altered tumor suppressors in lung adenocarcinoma. Inactivation of Lkb1 accelerates the growth and progression of oncogenic KRAS-driven lung tumors in mouse models. However, the molecular mechanisms by which LKB1 constrains lung tumorigenesis and whether the aggressive cancer state that stems from Lkb1 deficiency can be reverted remains unknown. To identify the processes governed by LKB1 in vivo, we generated an allele which enables Lkb1 inactivation during tumor development and subsequent Lkb1 restoration in established tumors. Restoration of Lkb1 in oncogenic KRAS-driven lung tumors suppressed proliferation and promoted tumor stasis. Lkb1 restoration activated targets of C/EBP transcription factors and drove the transition of neoplastic cells from a progenitor-like state to a less proliferative alveolar type II cell-like state. We show that C/EBP transcription factors govern a subset of genes that are induced by LKB1 and depend upon NKX2-1. We also demonstrate that a defining factor of the alveolar type II lineage, C/EBPα, constrains oncogenic KRAS-driven lung tumor growth. Thus, we uncover a role for a critical tumor suppressor in the regulation of key lineage-specific transcription factors, thereby constraining lung tumor development through the enforcement of differentiation.
2021-12-23 | PXD026738 | Pride
Project description:Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, irreversible, and lethal lung disease. The initiation of IPF involves microinjuries to and/or dysfunction of the alveolar epithelium, but factors that determine fibrosis progression or normal tissue repair are largely unknown. We previously demonstrated that autophagy inhibition-mediated epithelial-mesenchymal transition (EMT) in human alveolar epithelial type II (ATII) cells augments local myofibroblast differentiation in pulmonary fibrosis by paracrine signalling. Here, we report that liver kinase B1 (LKB1) inactivation in ATII cells induces autophagy inhibition and EMT as a consequence. In IPF lungs, this is caused by a downregulation of CAB39L, a key subunit within the LKB1 complex. 3D co-cultures of ATII cells and lung fibroblast MRC5 coupled with RNA sequencing (RNA-seq) confirmed that paracrine signalling between LKB1-depleted ATII cells and fibroblasts augmented myofibroblast differentiation. Together these data suggest that reduced autophagy caused by LKB1 inhibition can induce EMT in ATII cells and contribute to fibrosis via aberrant epithelial–fibroblast crosstalk.
2023-08-09 | GSE205965 | GEO
Project description:Inherited mutation in LKB1 results in the Peutz-Jeghers syndrome (PJS), characterized by intestinal hamartomas and a modestly increased frequency of gastrointestinal and breast cancer1. Somatic inactivation of LKB1 occurs in human lung adenocarcinoma2-4, but its tumor suppressor role in this tissue is unknown. Here we show that somatic Lkb1 deficiency strongly cooperates with somatic K-rasG12D activating mutation to accelerate the development of mouse lung tumorigenesis. Lkb1 deficiency in the setting of K-rasG12D mutation (K-ras Lkb1L/L) was associated with decreased tumor latency and increased tumor aggressiveness including metastasis. Furthermore, tumors from K-ras Lkb1L/L mice demonstrated histologies--squamous, adenosquamous and large cell--not seen with K-rasG12D mutation, Ink4a/Arf inactivation, or p53 inactivation alone or in combination. Experiments in vitro suggest that LKB1 suppresses lung tumorigenesis and progression through both p16INK4a-ARF-p53 dependent and independent mechanisms. These data indicate that LKB1 regulates lung tumor progression and differentiation. Keywords: cancer research To analyze the role of LKB1 in lung cancer progression and differentiation, we have dissected the lung tumors from mice with/without lkb1 loss and performed the microarray analyses to compare their gene expression pattern. In addition, we have also performed microarray analysis in both A549 and H2126 cell lines after reconsistitution of either wt-lkb1 or the kinase dead form of lkb1 (lkb1-KD) to confirm what we observed from in vivo studies.
2007-08-28 | E-GEOD-6135 | biostudies-arrayexpress
Project description:Background: LKB1 is among the most frequently altered tumor suppressors in lung adenocarcinoma. Inactivation of Lkb1 accelerates the growth and progression of oncogenic KRAS-driven lung tumors in mouse models. However, the molecular mechanisms by which LKB1 constrains lung tumorigenesis and whether the aggressive cancer state that stems from Lkb1 deficiency can be reverted remains unknown. Purpose: To determine whether the restoration of Lkb1 drives changes in cell state and/or abundance within established oncogenic KRAS-driven lung tumors. Approach: To control LKB1 function in vivo, we generated an Lkb1XTR allele, which enables Cre-mediated disruption of Lkb1 expression during tumor development and subsequent FLPo-ERT2-mediated reactivation of Lkb1 within established tumors. Lung tumors were initiated in KT;Lkb1XTR/XTR (non-restorable) and KT;Lkb1XTR/XTR;FLPo-ERT2 (restorable) mice with Lenti-Cre. Following tumor development, lung tumor-bearing were treated with either corn oil vehicle or tamoxifen for two weeks prior to isolating total viable cells by FACS for single cell RNA-seq. Results: Lkb1 restoration did not result in any dramatic changes in the relative abundance of stromal cell types beyond a significant increase in a rare population of putative mast cells. There was a marked shift in the epithelial compartment from an indeterminate state to an alveolar type II epithelial-like identity in response to Lkb1 restoration. Conclusions: The acute transcriptional response to Lkb1 restoration is largely limited to the neoplastic epithelial compartment.
2021-12-23 | GSE179501 | GEO
Project description:Background: LKB1 is among the most frequently altered tumor suppressors in lung adenocarcinoma. Inactivation of Lkb1 accelerates the growth and progression of oncogenic KRAS-driven lung tumors in mouse models. However, the molecular mechanisms by which LKB1 constrains lung tumorigenesis and whether the aggressive cancer state that stems from Lkb1 deficiency can be reverted remains unknown.Purpose: To assess the acute transcriptional response to Lkb1 restoration within established lung tumors in a genetically engineered mouse model of oncogenic KRAS-driven lung adenocarcinoma. Approach: To control LKB1 function in vivo, we generated an Lkb1XTR allele, which enables Cre-mediated disruption of Lkb1 expression during tumor development and subsequent FLPo-ERT2-mediated reactivation of Lkb1 within established tumors. Lung tumors were initiated in KrasLSL-G12D/+;R26LSL-tdTomato (KT; Lkb1 wild-type), KT;Lkb1XTR/XTR (non-restorable), and KT;Lkb1XTR/XTR;FLPo-ERT2 (restorable) mice with Lenti-Cre. Prior isolating neoplastic cells by FACS for gene expression profiling by RNA-seq, lung tumor-bearing were treated with either corn oil vehicle or tamoxifen for two weeks following tumor development. Results: Lkb1 restoration resulted in higher expression of markers of alveolar type II epithelial cells as well as gene sets relating to immunomodulation and lipid metabolism export, which are important functions of mature alveolar type II epithelial cells. Conclusions: LKB1 promotes the expression of C/EBP target genes and consequently drives features of alveolar type II epithelial cell differentiation.
2021-12-23 | GSE179500 | GEO
Project description:Respiratory infections, like the current pandemic SARS-CoV-2 virus, target the epithelial cells in the respiratory tract. However, alveolar macrophages (AMs) are tissue-resident macrophages located within the alveoli of the lung and they play a key role in the early phases of an immune response to respiratory infections. We expect that AMs are the first immune cells to encounter the SARS-CoV-2 and therefore their reaction to SARS-CoV-2 infection will have a profound impact upon the outcome of the infection. Interferons (IFNs) are antiviral cytokines and the first cytokine produced upon viral infection. Here, we challenge AMs with SARS-CoV-2 and to our surprise find that the AMs are incapable of recognising SARS-CoV-2 and produce IFN. This is in contrast to respiratory pathogens, such as influenza A virus and Sendai virus. Callenge of AMs with those viruses resulted in a robust IFN response. The absence of IFN production by AMs upon challenge could explain the initial asymptotic phase of SARS-CoV-2 infections and argues against the AMs as the source of proinflamatory cytokines later in infection.
2020-10-20 | PXD021685 | Pride
Project description:Background: LKB1 is among the most frequently altered tumor suppressors in lung adenocarcinoma. Inactivation of Lkb1 accelerates the growth and progression of oncogenic KRAS-driven lung tumors in mouse models. However, the molecular mechanisms by which LKB1 constrains lung tumorigenesis and whether the aggressive cancer state that stems from Lkb1 deficiency can be reverted remains unknown. By bulk gene expression profiling, Lkb1 restoration promotes the expression of markers and functions of alveolar type II cells, suggesting that LKB1 may govern a cell-state transition within the neoplastic epithelial compartment. Purpose: To determine whether the restoration of Lkb1 drives changes in cell state and/or abundance within established oncogenic KRAS-driven lung tumors. Approach: To control LKB1 function in vivo, we generated an Lkb1XTR allele, which enables Cre-mediated disruption of Lkb1 expression during tumor development and subsequent FLPo-ERT2-mediated reactivation of Lkb1 within established tumors. Lung tumors were initiated in KT;Lkb1XTR/XTR (non-restorable) and KT;Lkb1XTR/XTR;FLPo-ERT2 (restorable) mice with Lenti-Cre. Following tumor development, lung tumor-bearing were treated with either corn oil vehicle or tamoxifen for two weeks prior to isolating specifically neoplastic cells by FACS for single cell RNA-seq. Results: Single cell analysis revealed that the neoplastic epithelial compartment was composed of alveolar type I- and type II-like subpopulations, a Krt8+ transitional state, an actively proliferating subpopulations, and an indeterminate subpopulation partially resembling the alveolar type II-like identity. Dynamic inference analyses indicated that the indeterminate population represents an intermediate state along the alveolar type II to alveolar type I trans-differentiation trajectory. Notably, the indeterminate cluster was more proliferative than the alveolar type II-like subpopulation and exhibited higher expression of Sox9, which is a marker of distal lung epithelial progenitors. There was a marked shift in the epithelial compartment from the indeterminate state to alveolar type II epithelial-like identity in response to Lkb1 restoration. Conclusions: LKB1 governs the transition between a proliferative progenitor-like population and mature alveolar type II-like identity within oncogenic KRAS-driven lung tumors
2021-12-23 | GSE179502 | GEO
Project description:Background: LKB1 is among the most frequently altered tumor suppressors in lung adenocarcinoma. Inactivation of Lkb1 accelerates the growth and progression of oncogenic KRAS-driven lung tumors in mouse models. However, the molecular mechanisms by which LKB1 constrains lung tumorigenesis and whether the aggressive cancer state that stems from Lkb1 deficiency can be reverted remains unknown. Restoration of Lkb1 in established lung tumors promotes the expression of C/EBP target genes as well as features of alveolar type II cell differentiation, which requires the activity of C/EBP transcription factors in the developmental setting. Purpose: To determine the extent to which the disruption of C/EBP transcription factors recapitulates the transcriptional changes induced by the inactivation of Lkb1.Approach: To assess the changes gene expression induced by CRISPR/Cas9-mediated disruption of either C/EBP transcription factors or Lkb1, we induced lung tumors in KrasLSL-G12D/+;R26LSL-tdTomato;H11LSL-Cas9 mice using Lenti-sgNeo1/sgNT/sgNeo2/Cre (sgInert), Lenti-sgLkb1/Cre (sgLkb1), or Lenti-sgCebpa/sgCebpb/sgCebpd/Cre (sgCebpa/b/d). Neoplastic cells were then isolated from lung tumors by FACS for gene expression profiling by RNA-seq. Results: The disruption of C/EBP transcription factors partially recapitulates the gene expression changes induced by Lkb1 inactivation. Among the genes that are jointly dependent upon C/EBP transcription factors and LKB1 is an enrichment of NKX2-1-dependent target genes. Conclusions: C/EBP transcription factors likely operate downstream of LKB1 in an indirect manner, collaborating with another key developmental regulator, NKX2-1, to enforce alveolar type II cell differentiation to constrain tumor growth.
2021-12-23 | GSE179558 | GEO