Project description:Many cancer cells require more glycolytic adenosine triphosphate production due to a mitochondrial respiratory defect. However, the roles of mitochondrial defects in cancer development and progression remain unclear. To address the role of transcriptomic regulation by mitochondrial defects in liver cancer cells, we performed gene expression profiling for three different cell models of mitochondrial defects: cells with chemical respiratory inhibition (rotenone, thenoyltrifluoroacetone, antimycin A, and oligomycin), cells with mitochondrial DNA depletion (Rho0), and liver cancer cells harboring mitochondrial defects (SNU354 and SNU423). By comparing gene expression in the three models, we identified 10 common mitochondrial defectâ??related genes that may be responsible for retrograde signaling from cancer cell mitochondria to the intracellular transcriptome. The concomitant expression of the 10 common mitochondrial defect genes is significantly associated with poor prognostic outcomes in liver cancers, suggesting their functional and clinical relevance. Among the common mitochondrial defect genes, we found that nuclear protein 1 (NUPR1) is one of the key transcription regulators. Knockdown of NUPR1 suppressed liver cancer cell invasion, which was mediated in a Ca2+ signalingâ??dependent manner. In addition, by performing an NUPR1-centric network analysis and promoter binding assay, granulin was identified as a key downstream effector of NUPR1. We also report association of the NUPR1â??granulin pathway with mitochondrial defectâ??derived glycolytic activation in human liver cancer. Conclusion: Mitochondrial respiratory defects and subsequent retrograde signaling, particularly the NUPR1â??granulin pathway, play pivotal roles in liver cancer progression. 15 samples
Project description:Many cancer cells require more glycolytic adenosine triphosphate production due to a mitochondrial respiratory defect. However, the roles of mitochondrial defects in cancer development and progression remain unclear. To address the role of transcriptomic regulation by mitochondrial defects in liver cancer cells, we performed gene expression profiling for three different cell models of mitochondrial defects: cells with chemical respiratory inhibition (rotenone, thenoyltrifluoroacetone, antimycin A, and oligomycin), cells with mitochondrial DNA depletion (Rho0), and liver cancer cells harboring mitochondrial defects (SNU354 and SNU423). By comparing gene expression in the three models, we identified 10 common mitochondrial defect–related genes that may be responsible for retrograde signaling from cancer cell mitochondria to the intracellular transcriptome. The concomitant expression of the 10 common mitochondrial defect genes is significantly associated with poor prognostic outcomes in liver cancers, suggesting their functional and clinical relevance. Among the common mitochondrial defect genes, we found that nuclear protein 1 (NUPR1) is one of the key transcription regulators. Knockdown of NUPR1 suppressed liver cancer cell invasion, which was mediated in a Ca2+ signaling–dependent manner. In addition, by performing an NUPR1-centric network analysis and promoter binding assay, granulin was identified as a key downstream effector of NUPR1. We also report association of the NUPR1–granulin pathway with mitochondrial defect–derived glycolytic activation in human liver cancer. Conclusion: Mitochondrial respiratory defects and subsequent retrograde signaling, particularly the NUPR1–granulin pathway, play pivotal roles in liver cancer progression.
Project description:Mitochondrial fusion and fission, which are strongly related to normal mitochondrial function, are referred to as mitochondrial dynamics. Mitochondrial fusion defects in the liver cause a non-alcoholic steatohepatitis-like phenotype and liver cancer. However, whether mitochondrial fission defect directly impair liver function and stimulate liver disease progression, too, is unclear. Dynamin-related protein 1 (DRP1) is a key factor controlling mitochondrial fission. We hypothesized that DRP1 defects are a causal factor directly involved in liver disease development and stimulate liver disease progression. Drp1 defects directly promoted endoplasmic reticulum (ER) stress, hepatocyte death, and subsequently induced infiltration of inflammatory macrophages. Drp1 deletion increased the expression of numerous genes involved in the immune response and DNA damage in Drp1LiKO mouse primary hepatocytes. We administered lipopolysaccharide (LPS) to liver-specific Drp1-knockout (Drp1LiKO) mice and observed an increased inflammatory cytokine expression in the liver and serum caused by exaggerated ER stress and enhanced inflammasome activation. This study indicates that Drp1 defect-induced mitochondrial dynamics dysfunction directly regulates the fate and function of hepatocytes and enhances LPS-induced acute liver injury in vivo.
Project description:Nupr1 is a chromatin protein which cooperates with KrasG12D to induce PanIN formation in mice, though the molecular mechanisms underlying this effect remain to be fully characterized. In the current study, we find that Nupr1 acts as a gene modifier of the effect of KrasG12D-induced senescence by regulating Dnmt1 expression, changing the genome-wide levels of DNA methylation and activating the growth regulatory FoxO3a-Skp2-p27Kip1-pRb-E2F pathway. Congruently, 5-aza-2'-deoxycytydine, a general inhibitor of DNA methylation, reverses the KrasG12D-induced PanIN development through an effect on oncogene-induced senescence. Therefore, mechanistically this data reveals that epigenetic events modulate the functional outcome of genetic mutations during the progression of pancreatic cancer. The fact that small drug inhibitors of these epigenetic pathways reverse the effects triggered by genetic changes lends significant biomedical relevance to this knowledge for the future design of novel therapies aimed at controlling the progression of pancreatic cancer. The pancreatic gene expression profile of Nupr1 (+/+) Kras-G12D mouse was compared to the Nupr1 (-/-) Kras-G12D mouse.
Project description:In the advanced stages of cancer, autophagy is thought to promote tumor progression through its ability to mitigate various cellular stresses. However, the details of how autophagy is homeostatically regulated in such tumors are unknown. Here, we report that NUPR1 (nuclear protein 1, transcriptional regulator), a transcriptional coregulator, is aberrantly expressed in a subset of cancer cells and predicts low overall survival rates for lung cancer patients. NUPR1 regulates the late stages of autolysosome processing through the induction of the SNARE protein SNAP25, which forms a complex with the lysosomal SNARE associated protein VAMP8. NUPR1 depletion deregulates autophagic flux and impairs autolysosomal clearance, inducing massive cytoplasmic vacuolization and premature senescence in vitro and tumor suppression in vivo. Collectively, our data show that NUPR1 is a potent regulator of autolysosomal dynamics and is required for the progression of some epithelial cancers.
Project description:Hepatic steatosis is the result of an imbalance between nutrient delivery and metabolism in the liver. It is the first hallmark of Non-alcoholic fatty liver disease (NAFLD) and is characterized by the accumulation of excess lipids in the liver that can drive liver failure, inflammation, and cancer. Mitochondria control the fate and function of cells and compelling evidence implicates these multifunctional organelles in the appearance and progression of liver dysfunction, although it remains to be elucidated which specific mitochondrial functions are actually causally linked to NAFLD. In this study, we identified Mitochondrial Fission Process 1 protein (MTFP1) as a key regulator of mitochondrial and metabolic activity in the liver. Deletion of Mtfp1 in hepatocytes is physiologically benign in mice yet leads to the upregulation of oxidative phosphorylation (OXPHOS) complexes and mitochondrial respiration, independently of mitochondrial biogenesis. Consequently, hepatocyte-specific knockout mice are protected against high fat diet-induced hepatic steatosis and metabolic dysregulation. Additionally, we find that deletion of Mtfp1 in liver mitochondria inhibits mitochondrial permeability transition pore opening in hepatocytes, conferring protection against apoptotic liver damage in vivo and ex vivo. Our work uncovers novel functions of MTFP1 in the liver, positioning this gene as an unexpected regulator of OXPHOS and a therapeutic candidate for NAFLD.
Project description:Hepatic steatosis is the result of an imbalance between nutrient delivery and metabolism in the liver. It is the first hallmark of Non-alcoholic fatty liver disease (NAFLD) and is characterized by the accumulation of excess lipids in the liver that can drive liver failure, inflammation, and cancer. Mitochondria control the fate and function of cells and compelling evidence implicates these multifunctional organelles in the appearance and progression of liver dysfunction, although it remains to be elucidated which specific mitochondrial functions are actually causally linked to NAFLD. Here, we identified Mitochondrial Fission Process 1 protein (MTFP1) as a key regulator of mitochondrial and metabolic activity in the liver. Deletion of Mtfp1 in hepatocytes is physiologically benign in mice yet leads to the upregulation of oxidative phosphorylation (OXPHOS) complexes and mitochondrial respiration, independently of mitochondrial biogenesis. Consequently, hepatocyte-specific knockout mice are protected against high fat diet-induced hepatic steatosis and metabolic dysregulation. Additionally, we find that deletion of Mtfp1 in liver mitochondria inhibits mitochondrial permeability transition pore opening in hepatocytes, conferring protection against apoptotic liver damage in vivo and ex vivo. Our work uncovers novel functions of MTFP1 in the liver, positioning this gene as an unexpected regulator of OXPHOS and a therapeutic candidate for NAFLD.
Project description:The initial interaction between a microbial pathogen and the host immune response influences the outcome of the battle between the host and the foreign invader. Leprosy, caused by the obligate intracellular pathogen Mycobacterium leprae, provides a model to study relevant human immune responses. Previous studies have adopted a targeted approach to investigate host response to M. leprae infection, focusing on the induction of specific molecules and pathways. By measuring the host transcriptome triggered by M. leprae infection of human macrophages, we were able to detect a host gene signature 24–48 hours after infection characterized by specific innate immune pathways involving the cell fate mechanisms autophagy and apoptosis. The top upstream regulator in the M. leprae-induced gene signature was NUPR1, which is found in the M. leprae-induced cell fate pathways. The induction of NUPR1 by M. leprae was dependent on the production of the type I interferon (IFN), IFN-β. Furthermore, NUPR1 mRNA and protein were upregulated in the skin lesions from patients with the multibacillary form of leprosy. Together, these data indicate that M. leprae induces a cell fate program which includes NUPR1 as part of the host response in the progressive form of leprosy
Project description:Ultraviolet light is the dominant environmental oxidative skin stressor and a major skin aging factor. We studied which oxidized phospholipid (OxPL) mediators Ultraviolet A (UVA) would generate in primary human keratinocytes (KC). Mass spectrometric analysis of the oxidized phospholipidome of KC immediately or 24h post stress revealed dynamic changes in abundance of 174 oxidized phosphocholine species. Exposure to UVA and to in vitro UVA - oxidized phospholipids both activated, on transcriptome and proteome level, NRF2/antioxidant response signaling and lipid metabolizing enzyme expression, whereas UVA additionally initiated the unfolded protein response (UPR). We identified Nupr1 as an upstream transcriptional regulator of UVA/OxPL mediated gene expression that is itself transcriptionally regulated by reactive lipids, which also aggregate and crosslink recombinant Nupr1 protein. Nupr1 governs the basal and stress regulated expression of cell cycle, redox reactive, autophagy- and lipid metabolizing genes in epidermal keratinocytes, making it a potential key factor in skin ROS responses, -aging and -pathology.
Project description:<p>Alcoholic hepatitis (AH) is a life-threatening condition characterized by profound hepatocellular dysfunction for which targeted treatments are urgently needed. Identification of molecular drivers is hampered by the lack of suitable animal models. By performing RNA sequencing in livers from patients with different phenotypes of alcohol-related liver disease (ALD), we describe the transcriptional programs involved in disease progression. We uncovered that development of AH is characterized by the defective activity of liver-enriched transcription factors (LETFs). The PPARG predicted activation state was found increased in early forms of ALD, while AH was associated by a marked decrease in HNF4A-dependent gene expression along with a marked expression of the fetal HNF4A isoform (P2). TGFB1, a key upstream transcriptome regulator in AH, induced the use of HNF4a P2 promoter in hepatocytes, which resulted in abnormal bile acid synthesis and defective metabolic and synthetic functions. PPARG agonists partially prevented this effect. We conclude that targeting TGFB1 and epigenetic drivers that modulate HNF4A-dependent gene expression could be beneficial to improve hepatocellular function in patients with AH.</p> <p>The study was conducted thanks to a multicenter collaboration under the National Institute of Alcohol Abuse and Alcoholism (NIAAA)-funded consortium: <b>Integrated Approaches for Identifying Molecular Targets in Alcoholic Hepatitis</b> (InTEAM).</p>