Gene expression profiles of Lkb1 WT and KO hematopoietic stem cells (HSCs)
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE24765 | GEO | 2010/12/01
SECONDARY ACCESSION(S): PRJNA132207
REPOSITORIES: GEO
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Project description:LKB1 encodes a Ser/Thr kinase and acts as an evolutionarily conserved sensor of cellular energy status in eukaryotic cells. LKB1 functions as the major upstream kinase to phosphorylate AMPK and 12 other AMPK-related kinases, which is required for their activation in many cellular contexts. Once activated, AMPK and AMPK-related kinases phosphorylate a diverse array of downstream effectors to switch on ATP-generating catabolic processes and switch off ATP-consuming anabolic processes, thus restoring energy balance during periods of energetic stress. To study the role and mechanisms of Lkb1 in the regulation of hematopoietic stem cell (HSC) biology, we performed transcriptome analysis of sorted LSK (Lin-, Sca-1+, c-Kit+) cells from Lkb1 WT and KO bone marrows at 1 day post-completing tamoxifen injection (DPI). To identify more proximal molecular effects, we chose 1 DPI due to the modest phenotypes in Lkb1 KO mice, yet documentation of efficient Lkb1 deletion in LSK cells at this very early time point. We treated Lkb1 L/L rosa26CreERT2 and Lkb1 L/L mice (C57BL/Ka-CD45.2:Thy-1.1 background) with Tamoxifen for 5 days to somatically delete Lkb1 in adult mice, and generated Lkb1 WT and KO mice. At 1 DPI, we prepared single-cell suspensions from bone marrow (from femoral and tibial bones), and stained and sorted LSK populations using FACSAria (Becton Dickinson, Mountain View, CA). The RNA was extracted from sorted LSK cells, amplified and subjected to gene profiling. The samples include 3 Lkb1 WT (Lkb1 WT 5-7) and 4 Lkb1 KO (Lkb1 KO 4-7) replicates.
2010-12-01 | E-GEOD-24765 | biostudies-arrayexpress
Project description:The 5' AMP-activated protein kinase (AMPK) is a master energy sensing kinase that is regulated by phosphorylation of Thr172 in its activation loop. Three kinases can phosphorylate AMPK at Thr172: the tumor suppressor LKB1, CAMKK2 and TAK1. While LKB1- and CAMKK2-mediated AMPK Thr172 phosphorylation have been well-characterized, much less is known about TAK1-dependent AMPK phosphorylation. An important target of TAK1 is IκB kinase (IKK) which controls NF-B transcription factor activation. Here, we tested the hypothesis that IKK acted downstream of TAK1 to activate AMPK by phosphorylating Thr172. IKK was required for phosphorylation of Thr172 in AMPK in response to treatment with IL-1 or TNF- treatment or by TAK1 overexpression. Additionally, IKK regulated basal AMPK Thr172 phosphorylation in several cancer cell types independently of TAK1, indicating that other modes of IKK activation could lead to AMPK activation. We found that IKK directly phosphorylated AMPK at Thr172 independently of LKB1 or energy stress. This finding indicated that while LKB1 activates AMPK as a sensor of energetic stress, IKK activated AMPK in response to extracellular inflammatory signals and through distinct pathways downstream of IKK activation. Accordingly, in LKB1-deficient cells, IKK inhibition caused a reduction in AMPK Thr172 phosphorylation in response to the mitochondrial inhibitor phenformin. This response led to enhanced apoptosis and suggests that IKK inhibition in combination with phenformin could be used clinically to treat patients with LKB1-deficient cancers.
2018-07-16 | PXD009897 | Pride
Project description:5’-AMP-Activated Protein Kinase (Ampk) is an energy gatekeeper that responds to decreases in available ATP by inhibiting energy-consuming processes like protein synthesis and promoting energy-generating processes like glucose uptake. Recently, our lab showed that Lkb1, a previously unstudied kinase in B cell immunology and the main upstream kinase of Ampk, had a critical and unexpected role in B cell activation and germinal center formation. In T cells knockout of the downstream target Ampk, only partially phenocopies Lkb1 deletion, so we sought to determine whether the role of Lkb1 in B cells depends on Ampk. We find Ampk is activated upon B cell stimulation in vitro. Surprisingly, however, Ampk activation occurs in the absence of energetic stress, and B cells continue to grow and divide despite Ampk activity. We performed an IP-MS substrate screen to identify Ampk targets and only identified a limited repertoire of canonical targets, and many non-canonical targets. Despite activation of Ampk and the major role of Lkb1 in B cell activation, B cell specific deletion of Ampk does not significantly affect B cell activation, differentiation, carbon handling, gene expression, or humoral immune responses. The only major effect of Ampk loss was accelerated downregulation of IgD during stimulation, which was preceded by downregulation of the IgD regulator Zfp318. Early activation of Ampk by pharmacological means also has little impact on B cell function, although treatment with the biguanide Phenformin critically impairs germinal center formation and class switch recombination in vivo, but does not significantly impair antigen-specific antibody responses. Combined, our results suggest an unexpected and unexplained activation of Ampk in B cells.
2019-06-16 | GSE121025 | GEO
Project description:Adipose tissue is a metabolic and endocrine organ that secretes numerous bioactive molecules called adipocytokines. Among these, adiponectin has been argued to have a crucial role in obesity-associated breast cancer. The key molecule of adiponectin signaling is AMP-activated protein kinase (AMPK), mainly activated by Liver Kinase B1 (LKB1). Here, we demonstrated how the ERalfa/LKB1 interaction may negatively interfere with the capability of LKB1 to phosphorylate AMPK and then inhibit its downstream signaling TSC2/mTOR/p70S6k. In MCF-7 cells upon adiponectin AMPK signaling was not working, keeping its downstream protein Acetyl-CoA Carboxylase (ACC) still active. In contrast, in MDA-MB-231 cells the phosphorylation of AMPK and ACC was enhanced with consequent inhibition of both lipogenesis and cell growth. Thus, upon adiponectin, ERalfa signaling switched the energy balance of breast cancer cells towards a lipogenic phenotype. In other words, adiponectin in all the concentrations tested played an inhibitory role on ERalpha-negative breast cancer cell growth and progression either in vitro or in vivo. In contrast, low adiponectin levels, similar to those circulating in obese patients, worked on ERalfa-positive cells as a growth factor, stimulating their growth and progression. The latter effect seems to be blunted in vivo only in the presence of high adiponectin concentration. Based on the present results, it can be concluded that if we prospectively address adiponectin as a pharmacological tool, a separate therapeutic treatment should be carefully assessed in ERalfa-positive and negative breast-cancer patients.
2020-02-27 | E-MTAB-6120 | biostudies-arrayexpress
Project description:Transcriptional profiling to assess atrial gene expression in atrial LKB1 KO vs. AMPK KO vs. WT mice.
2022-04-05 | GSE200144 | GEO
Project description:RNA-Seq was performed on pancreatic islets from four transgenic mouse strains affecting LKB1 and AMPK. A conditional LKB1 knockout strain was generated. Double conditional knockouts for AMPK alpha1 and AMPK alpha2 were also generated. These conditional strains were crossed with RIP-Cre (driven by rat insulin promoter) or Ins1-Cre mice to generate LKB1 knockout and AMPK double knockout strains.
2014-10-25 | E-MTAB-2791 | biostudies-arrayexpress
Project description:Diacylglycerol lipase-beta (DAGLB) serves as a principal 2-arachidonoylglycerol (2-AG) biosynthetic enzyme regulating endocannabinoid and eicosanoid metabolism in immune cells including macrophages and dendritic cells. Genetic or pharmacological inactivation of DAGLb ameliorates inflammation and hyper-nociception in preclinical models of pathogenic pain. These beneficial effects have been assigned principally to reductions in downstream pro-inflammatory lipid signaling, leaving alternative mechanisms of regulation largely underexplored. Here, we apply quantitative chemical- and phospho-proteomics to discover that disruption of DAGLb in primary macrophages leads to LKB1-AMPK signaling activation, resulting in reprogramming of the phosphoproteome and bioenergetics. Notably, AMPK inhibition reversed the antinociceptive effects of DAGLb blockade, thereby directly supporting DAGLβ-AMPK crosstalk in vivo. Our findings uncover signaling between endocannabinoid biosynthetic enzymes and ancient energy sensing kinases to mediate cell biological and pain responses.
2024-01-02 | GSE249312 | GEO
Project description:Hepatocellular carcinoma (HCC) is the first cause of death in cirrhotic patients. Liver cirrhosis at a high risk of HCC has abnormal S-Adenosylmethionine (SAMe) levels. Catabolism of SAMe is mainly mediated by Glycine N-methyltransferase (GNMT), Lack in GNMT expression leads to epigenetic regulation of critical carcinogenesis pathways and mounting evidence assigns an essential role of GNMT in HCC. Methods: Here we have studied the role of LKB1-AMPK and RAS in the proliferation and transformation of GNMT-deficient HCC. Results. GNMT-deficient HCC was characterized by LKB1-AMPK misconnection, leading to resistance of apoptosis response mediated by a positive regulation of cAMP-PKA-CaMKKM-NM-2 cascade. Additionally, Ras-mediated hyperactivation of LKB1 contributes to the proliferation of GNMT-deficient HCC in an ERK/p90RSK-dependent manner. The observed LKB1-induced Ras activation, was due to the regulation of RASGRP3 expression. Notably, the human HCC tumors with poorer prognosis showed the lowest levels of GNMT, p-AMPKM-NM-1(Thr172) and the highest activation of Ras/LKB1/RASGRP3 axis. The present data suggest a correlation between LKB1 and RAS activity in a context of HCC with low GNMT expression, indicating that activation of the RAS/LKB1/RASGRP3 cascade might possess an important prognostic role in human liver cancer. Furthermore, these findings open the possibility to design new therapeutic strategies for the treatment of liver cancer. HCC induced wild-type or Gnmt knockout mice at 3 weeks old were used for RNA extraction and hybridization on Illumina microarrays. The study comprises three groups of samples: OKER cell line(n=3), GNMT-KO mouse hepatocytes (n=3) ,GNMT-WT mouse hepatocytes(n=3)
2012-06-30 | E-GEOD-34838 | biostudies-arrayexpress
Project description:The phosphorylation state of human HA-tagged-SIK2, adenovirally introduced in murine hepatocytes (C57/BL/6 strain) was analysed in unstimulated and in response to glucagon- or insulin- treated conditions. Background:- LKB1 is a master kinase that regulates metabolism and growth through AMPK and 12 other closely-related kinases. Liver-specific ablation of LKB1 causes increased glucose production in hepatocytes in vitro and hyperglycaemia in fasting mice in vivo. The salt-inducible kinases (SIK1, 2 and 3), members of the AMPK-related kinase family, play a key role as gluconeogenic suppressor downstream of LKB1 in the liver. A selective SIK inhibitor (HG-9-91-01) promotes dephosphorylation of transcriptional co-activators CRTC2/3 resulting in enhanced gluconeogenic gene expression and glucose production in hepatocytes, an effect that is abolished when an HG-9-91-01-insensitive-mutant-SIK is introduced or LKB1 is ablated. Although SIK2 was proposed as a key regulator of insulin-mediated suppression of gluconeogenesis, we provide genetic evidence that liver-specific ablation of SIK2 alone has no effect on gluconeogenesis and insulin does not modulate SIK2 phosphorylation/activity. Collectively, we demonstrate that the LKB1-SIK pathway functions as a key gluconeogenic gatekeeper in the liver.
2014-08-08 | PXD001032 | Pride
Project description:Purpose: Mutations in STK11 (LKB1) occur in 17% of lung adenocarcinoma (LUAD) and drive a suppressive (cold) tumor immune microenvironment (TME) and resistance to immunotherapy. The mechanisms underpin the establishment and maintenance of a cold TME in LKB1 mutant LUAD remain poorly understood and the identification of downstream effectors is critical to inform therapeutic strategies to invigorate antitumor immunity. In this study, we investigated the association between inactivation of AMPK, one of the downstream substrates of LKB1, and immune evasion in human LUAD as well as the causal role of AMPK on TME in genetically engineered mouse model (GEMM) of LUAD. Experimental Design: We modeled AMPK inactivation in vivo using GEMM by deleting both AMPKα1 (Prkaa1) and AMPKα2 (Prkaa2) in KrasG12D-driven LUAD (KAA). Furthermore, we investigated the impact of AMPK inactivation on immune cell infiltration and global gene-expression programs of murine LUAD. Gene expression signature from AMPK-deficient murine LUAD was further compared to that of Lkb1 deficient murineLUAD as well as human LUAD with either LKB1 mutation or attenuated AMPK phosphorylation. Results: Inactivation of both AMPKα1 and AMPKα2 accelerates KrasG12D-driven LUAD. AMPK-deficient tumors are characterized with reduced infiltration of CD8+/CD4+ T cells and gene signatures associated with compromised immune microenvironment, which resembles LKB1-deficient murine and human LUAD (KL) as well as LKB1-wildtype LUAD with reduced AMPK phosphorylation. Attenuation of the MHC Class 1 component ß2 microglobulin (ß2M) was identified as a shared feature in KL and KAA murine LUAD as well as in human LUAD with either LKB1 mutations or reduced AMPK phosphorylation. Furthermore, reactivation of AMPK by expression of constitutive active form of AMPKα1 leads to restoration of ß2M level in LKB1 mutant LUAD cells. Conclusions: The results identify attenuation of the LKB1 substrate AMPK as an important mechanism for decreased MHC Class 1 expression and immune evasion in LKB1 mutant LUAD. Translational relevance: LKB1 loss-of-function mutations rank as the third most common genetic alterations found in lung adenocarcinoma and associated with immune evasion. In the current study, on the basis of GEMM of LUAD we established the causal relationship between inactivation of the LKB1 substrate AMPK and immune evasion. Furthermore we find that the status of AMPK phosphorylation is more sensitive than LKB1 mutation in predicting impaired tumor immune microenvironment and likely also for the resistance to immunotherapy. The results also suggest that restoration of AMPK activity could increase the number of patients benefiting from immunotherapy.
2022-01-26 | GSE175479 | GEO