LKB1-AMPK axis negatively regulates ferroptosis by inhibiting fatty acid synthesis.
Ontology highlight
ABSTRACT:
SUBMITTER: Li C
PROVIDER: S-EPMC7471309 | biostudies-literature | 2020 Sep
REPOSITORIES: biostudies-literature
Publications
LKB1-AMPK axis negatively regulates ferroptosis by inhibiting fatty acid synthesis.
Li Changzhi C Dong Xuan X Du Wenjing W Shi Xin X Chen Kangjie K Zhang Wei W Gao Minghui M
Signal transduction and targeted therapy 20200903 1
Similar Datasets
Project description:The receptor-interacting serine/threonine-protein kinases RIPK1 and RIPK3 play important roles in necroptosis that are closely linked to the inflammatory response. Although the activation of necroptosis is well characterized, the mechanism that tunes down necroptosis is largely unknown. Here we find that Parkin (also known as PARK2), an E3 ubiquitin ligase implicated in Parkinson's disease and as a tumour suppressor, regulates necroptosis and inflammation by regulating necrosome formation. Parkin prevents the formation of the RIPK1-RIPK3 complex by promoting polyubiquitination of RIPK3. Parkin is phosphorylated and activated by the cellular energy sensor AMP-activated protein kinase (AMPK). Parkin deficiency potentiates the RIPK1-RIPK3 interaction, RIPK3 phosphorylation and necroptosis. Parkin deficiency enhances inflammation and inflammation-associated tumorigenesis. These findings demonstrate that the AMPK-Parkin axis negatively regulates necroptosis by inhibiting RIPK1-RIPK3 complex formation; this regulation may serve as an important mechanism to fine-tune necroptosis and inflammation.
| S-EPMC6679774 | biostudies-literature
Project description:Background/objectivesFerroptosis is a type of regulated cell death that involves iron-dependent accumulation of lipid peroxides. Because fibroblast-like synoviocytes (FLSs) in patients with rheumatoid arthritis (RA) have a hyperplastic and inflammatory phenotype, selective induction of FLS cell death is considered a potential treatment strategy for RA. Liver kinase B1 (LKB1)-activated AMP-activated protein kinase (AMPK) signaling regulates the inflammation and migration of RA FLSs, contributing to RA pathogenesis. Here, we aimed to determine the effect of LKB1 knockdown on the ferroptosis pathway in RA FLSs.MethodsSynovial tissues from patients with RA (n = 5) were transfected with siRNA targeting LKB1. Cell viability was evaluated via 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and Annexin V/7-aminoactinomycin D (7-AAD) staining. Ferroptosis was assessed using boron-dipyrromethene (BODIPY) lipid probes, a ferrous ion detection kit, and a glutathione detection assay. Expression of hallmarks of various cell death pathways was analyzed using western blot.ResultsRA FLS cell death significantly increased after transfection with LKB1 siRNA (p < 0.01). Lipid peroxidation was upregulated and the expression levels of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) were suppressed in LKB1-deficient cells. Additionally, LKB1 inhibition made RA FLSs highly sensitive to ferroptosis. When RA FLSs were incubated with an activator of AMPK, LKB1 knockdown-mediated inhibition was restored through upregulated expression of GPX4 and SLC7A11.Conclusionsthese findings suggest that LKB1-AMPK signaling is essential to protect RA FLSs against ferroptosis.
| S-EPMC11853117 | biostudies-literature
Project description:Altered protein ubiquitination is associated with cancer. The novel tripartite motif (TRIM) family of E3 ubiquitin ligases have been reported to play crucial roles in the development, growth, and metastasis of various tumors. The TRIM family member TRIM27 acts as a potential promoter of tumor development in a wide range of cancers. However, little is known regarding the biological features and clinical relevance of TRIM27 in glioblastoma (GBM). Here, we report findings of elevated TRIM27 expression in GBM tissues and GBM cell lines. Further functional analysis showed that TRIM27 deletion inhibited GBM cell growth both in vitro and in vivo. Furthermore, we found that TRIM27 promoted the growth of GBM cells by enhancing the Warburg effect. Additionally, the inactivation of the LKB1/AMPK/mTOR pathway was critical for the oncogenic effects of TRIM27 in GBM. Mechanistically, TRIM27 could directly bind to LKB1 and promote the ubiquitination and degradation of LKB1, which in turn enhanced the Warburg effect and GBM progression. Collectively, these data suggest that TRIM27 contributes to GNM pathogenesis by inhibiting the LKB1/AMPK/mTOR axis and may be a promising candidate as a potential diagnostic and therapeutic marker for patients with GBM.
| S-EPMC11301283 | biostudies-literature
Project description:Defective autophagy and lipotoxicity are the hallmarks of nonalcoholic fatty liver disease. However, the precise molecular mechanism for the defective autophagy in lipotoxic conditions is not fully known. In the current study, we elucidated that activation of the mammalian target of rapamycin complex 1 (mTORC1)-G9a-H3K9me2 axis in fatty acid-induced lipotoxicity blocks autophagy by repressing key autophagy genes. The fatty acid-treated cells show mTORC1 activation, increased histone methyltransferase G9a levels, and suppressed autophagy as indicated by increased accumulation of the key autophagic cargo SQSTM1/p62 and decreased levels of autophagy-related proteins LC3II, Beclin1, and Atg7. Our chromatin immunoprecipitation analysis showed that decrease in autophagy was associated with increased levels of the G9a-mediated repressive H3K9me2 mark and decreased RNA polymerase II occupancy at the promoter regions of Beclin1 and Atg7 in fatty acid-treated cells. Inhibition of mTORC1 in fatty acid-treated cells decreased G9a-mediated H3K9me2 occupancy and increased polymerase II occupancy at Beclin1 and Atg7 promoters. Furthermore, mTORC1 inhibition increased the expression of Beclin1 and Atg7 in fatty acid-treated cells and decreased the accumulation of SQSTM1/p62. Interestingly, the pharmacological inhibition of G9a alone in fatty acid-treated cells decreased the H3K9me2 mark at Atg7 and Beclin1 promoters and restored the expression of Atg7 and Beclin1. Taken together, our findings have identified the mTORC1-G9a-H3K9me2 axis as a negative regulator of the autophagy pathway in hepatocellular lipotoxicity and suggest that the G9a-mediated epigenetic repression is mechanistically a key step during the repression of autophagy in lipotoxic conditions.
| S-EPMC9957777 | biostudies-literature
Project description:N-methyl-D-aspartate receptors (NMDARs) are ligand-gated, voltage-dependent channels of the ionotropic glutamate receptor family. The present study explored whether NMDAR activation induced ferroptosis in vascular endothelial cells and its complicated mechanisms in vivo and in vitro. Various detection approaches were used to determine the ferroptosis-related cellular iron content, lipid reactive oxygen species (LOS), siRNA molecules, RNA-sequence, MDA, GSH, and western blotting. The AMPK activator Acadesine (AICAR), HMGB1 inhibitor glycyrrhizin (GLY), PP2A inhibitor LB-100, and NMDAR inhibitor MK801 were used to investigate the involved in vivo and in vitro pathways. The activation of NMDAR with L-glutamic acid (GLU) or NMDA significantly promoted cellular ferroptosis, iron content, MDA, and the PTGS2 expression, while decreasing GPX4 expression and GSH concentration in human umbilical vein endothelial cells (HUVECs), which was reversed by ferroptosis inhibitors Ferrostatin-1(Fer-1), Liproxstatin-1 (Lip-1), or Deferoxamine (DFO). RNA-seq revealed that ferroptosis and SLC7A11 participate in NMDA or GLU-mediated NMDAR activation. The PP2A-AMPK-HMGB1 pathway was majorly associated with NMDAR activation-induced ferroptosis, validated using the PP2A inhibitor LB-100, AMPK activator AICAR, or HMGB1 siRNA. The role of NMDAR in ferroptosis was validated in HUVECs induced with the ferroptosis activator errasin or RSL3 and counteracted by the NMDAR inhibitor MK-801. The in vivo results showed that NMDA- or GLU-induced ferroptosis and LOS production was reversed by MK-801, LB-100, AICAR, MK-801, and GLY, confirming that the PP2A-AMPK-HMGB1 pathway is involved in NMDAR activation-induced vascular endothelium ferroptosis. In conclusion, the present study demonstrated a novel role of NMDAR in endothelial cell injury by regulating ferroptosis via the PP2A-AMPK-HMGB1 pathway.
| S-EPMC10794209 | biostudies-literature
Project description:Acute kidney injury (AKI) is a common and life-threatening condition associated with cell death, where ferroptosis plays a critical role. Chemerin, primarily produced in white adipose tissue, has multiple biological functions in renal pathophysiology. However, to date, whether and how chemerin regulates the progression of AKI remain unclear. Here, we found that chemerin expression was reduced in both AKI model mice and cells. Similarly, serum chemerin levels were also decreased in AKI patients. The administration of recombinant chemerin improves renal function in ischemia-reperfusion (I/R) model mice. Chemerin significantly attenuates ferroptosis in kidneys. In TCMK-1 cells, chemerin knockdown further aggravates ferroptosis. Mechanistically, chemerin activates AMP-activated protein kinase (AMPK), which induces the phosphorylation of nuclear factor erythroid 2-related factor 2 (NRF2) in renal tubular cells. Subsequently, NRF2 translocates into the nucleus, where it stimulates the expression of cystine/glutamate antiporter solute carrier (SLC7A11). As a result, cystine uptake and glutathione (GSH) biosynthesis in renal tubular cells were increased, which confers cells with higher capacity against ferroptosis. Overall, our findings indicate that chemerin plays a protective role in AKI by repressing ferroptosis in renal tubular cells, which is likely due to the activation in the AMPK/NRF2/SLC7A11 axis.
| S-EPMC11659585 | biostudies-literature
Project description:Cellular senescence provides a protective barrier against tumorigenesis in precancerous or normal tissues upon distinct stressors. However, the detailed mechanisms by which tumor cells evade premature senescence to malignant progression remain largely elusive. Here we reported that RBM4 adversely impacted cellular senescence to favor glutamine-dependent survival of esophageal squamous cell carcinoma (ESCC) cells by dictating the activity of LKB1, a critical governor of cancer metabolism. The level of RBM4 was specifically elevated in ESCC compared to normal tissues, and RBM4 overexpression promoted the malignant phenotype. RBM4 contributed to overcome H-RAS- or doxorubicin-induced senescence, while its depletion caused P27-dependent senescence and proliferation arrest by activating LKB1-AMPK-mTOR cascade. Mechanistically, RBM4 competitively bound LKB1 to disrupt the LKB1/STRAD/MO25 heterotrimeric complex, subsequently recruiting the E3 ligase TRIM26 to LKB1, promoting LKB1 ubiquitination and degradation in nucleus. Therefore, such molecular process leads to bypassing senescence and sustaining cell proliferation through the activation of glutamine metabolism. Clinically, the ESCC patients with high RBM4 and low LKB1 have significantly worse overall survival than those with low RBM4 and high LKB1. The RBM4 high/LKB1 low expression confers increased sensitivity of ESCC cells to glutaminase inhibitor CB-839, providing a novel insight into mechanisms underlying the glutamine-dependency to improve the efficacy of glutamine inhibitors in ESCC therapeutics.
| S-EPMC10119322 | biostudies-literature
Project description:Dysregulation of de novo lipogenesis (DNL) has recently gained strong attention as being one of the critical factors that contribute to the assessment of non-alcoholic fatty liver disease (NAFLD). NAFLD is often diagnosed in patients with dyslipidemias and type 2 diabetes; thus, an interesting correlation can be deduced between high hematic free fatty acids and glucose excess in the DNL dysregulation. In the present study, we report that, in a cellular model of NAFLD, the coexistence of elevated glucose and FFA conditions caused the highest cellular lipid accumulation. Deepening the molecular mechanisms of the DNL dysregulation-RT-qPCR and immunoblot analysis demonstrated increased expression of mitochondrial citrate carrier (CiC), cytosolic acetyl-CoA carboxylase 1 (ACACA), and diacylglycerol acyltransferase 2 (DGAT2) involved in fatty acids and triglycerides synthesis, respectively. XBP-1, an endoplasmic reticulum stress marker, and SREBP-1 were the transcription factors connected to the DNL activation. Quercetin (Que), a flavonoid with strong antioxidant properties, and noticeably reduced the lipid accumulation and the expression of SREBP-1 and XBP-1, as well as of their lipogenic gene targets in steatotic cells. The anti-lipogenic action of Que mainly occurs through a strong phosphorylation of ACACA, which catalyzes the committing step in the DNL pathway. The high level of ACACA phosphorylation in Que-treated cells was explained by the intervention of AMPK together with the reduction of enzymatic activity of PP2A phosphatase. Overall, our findings highlight a direct anti-lipogenic effect of Que exerted through inhibition of the DNL pathway by acting on ACACA/AMPK/PP2A axis; thus, suggesting this flavonoid as a promising molecule for the NAFLD treatment.
| S-EPMC8834998 | biostudies-literature
Project description:Lipid metabolism is important for health and insulin action, yet the fundamental process of regulating lipid metabolism during muscle contraction is incompletely understood. Here, we show that liver kinase B1 (LKB1) muscle-specific knockout (LKB1 MKO) mice display decreased fatty acid (FA) oxidation during treadmill exercise. LKB1 MKO mice also show decreased muscle SIK3 activity, increased histone deacetylase 4 expression, decreased NAD? concentration and SIRT1 activity, and decreased expression of genes involved in FA oxidation. In AMP-activated protein kinase (AMPK)?2 KO mice, substrate use was similar to that in WT mice, which excluded that decreased FA oxidation in LKB1 MKO mice was due to decreased AMPK?2 activity. Additionally, LKB1 MKO muscle demonstrated decreased FA oxidation in vitro. A markedly decreased phosphorylation of TBC1D1, a proposed regulator of FA transport, and a low CoA content could contribute to the low FA oxidation in LKB1 MKO. LKB1 deficiency did not reduce muscle glucose uptake or oxidation during exercise in vivo, excluding a general impairment of substrate use during exercise in LKB1 MKO mice. Our findings demonstrate that LKB1 is a novel molecular regulator of major importance for FA oxidation but not glucose uptake in muscle during exercise.
| S-EPMC3636614 | biostudies-literature
Project description:Acute kidney injury (AKI) is a common and life-threatening condition associated with cell death, where ferroptosis plays a critical role. Chemerin, primarily produced in white adipose tissue, has multiple biological functions in renal pathophysiology. However, to date, whether and how chemerin regulates the progression of AKI remain unclear. Here, we found that chemerin expression was reduced in both AKI model mice and cells. Similarly, serum chemerin levels were also decreased in AKI patients. The administration of recombinant chemerin improves renal function in ischemia-reperfusion (I/R) model mice. Chemerin significantly attenuates ferroptosis in kidneys. In TCMK-1 cells, chemerin knockdown further aggravates ferroptosis. Mechanistically, chemerin activates AMP-activated protein kinase (AMPK), which induces the phosphorylation of nuclear factor erythroid 2-related factor 2 (NRF2) in renal tubular cells. Subsequently, NRF2 translocates into the nucleus, where it stimulates the expression of cystine/glutamate antiporter solute carrier (SLC7A11). As a result, cystine uptake and glutathione (GSH) biosynthesis in renal tubular cells were increased, which confers cells with higher capacity against ferroptosis. Overall, our findings indicate that chemerin plays a protective role in AKI by repressing ferroptosis in renal tubular cells, which is likely due to the activation in the AMPK/NRF2/SLC7A11 axis.
2024-12-01 | GSE283126 | GEO