ABSTRACT
Tissue homeostasis requires lineage fidelity of stem cells. Dysregulation of cell fate specification and differentiation leads to various diseases, yet the cellular and molecular mechanisms governing these processes remain elusive. We demonstrate that YAP/TAZ activation reprograms airway secretory cells, which subsequently lose their cellular identity and acquire squamous alveolar type 1 (AT1) fate in the lung. This cell fate conversion is mediated via distinctive transitional cell states of damage-associated transient progenitors (DATPs), recently shown to emerge during injury repair in mouse and human lungs. We further describe a YAP/TAZ signaling cascade to be integral for the fate conversion of secretory cells into AT1 fate, by modulating mTORC1/ATF4-mediated amino acid metabolism in vivo. Importantly, we observed aberrant activation of the YAP/TAZ-mTORC1-ATF4 axis in the altered airway epithelium of bronchiolitis obliterans syndrome, including substantial emergence of DATPs and AT1 cells with severe pulmonary fibrosis. Genetic and pharmacologic inhibition of mTORC1 activity suppresses lineage alteration and subepithelial fibrosis driven by YAP/TAZ activation, proposing a potential therapeutic target for human fibrotic lung diseases.
Subject(s)
Adaptor Proteins, Signal Transducing , YAP-Signaling Proteins , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Amino Acids, Essential , Animals , Cell Differentiation , Mechanistic Target of Rapamycin Complex 1/genetics , Mechanistic Target of Rapamycin Complex 1/metabolism , MiceABSTRACT
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by various disabling symptoms including exercise intolerance and is diagnosed in the absence of a specific cause, making its clinical management challenging. A better understanding of the molecular mechanism underlying this apparent bioenergetic deficiency state may reveal insights for developing targeted treatment strategies. We report that overexpression of Wiskott-Aldrich Syndrome Protein Family Member 3 (WASF3), here identified in a 38-y-old woman suffering from long-standing fatigue and exercise intolerance, can disrupt mitochondrial respiratory supercomplex formation and is associated with endoplasmic reticulum (ER) stress. Increased expression of WASF3 in transgenic mice markedly decreased their treadmill running capacity with concomitantly impaired respiratory supercomplex assembly and reduced complex IV levels in skeletal muscle mitochondria. WASF3 induction by ER stress using endotoxin, well known to be associated with fatigue in humans, also decreased skeletal muscle complex IV levels in mice, while decreasing WASF3 levels by pharmacologic inhibition of ER stress improved mitochondrial function in the cells of the patient with chronic fatigue. Expanding on our findings, skeletal muscle biopsy samples obtained from a cohort of patients with ME/CFS showed increased WASF3 protein levels and aberrant ER stress activation. In addition to revealing a potential mechanism for the bioenergetic deficiency in ME/CFS, our study may also provide insights into other disorders associated with fatigue such as rheumatic diseases and long COVID.
Subject(s)
COVID-19 , Fatigue Syndrome, Chronic , Animals , Female , Humans , Mice , COVID-19/metabolism , Fatigue Syndrome, Chronic/diagnosis , Mitochondria/metabolism , Post-Acute COVID-19 Syndrome , Respiration , Wiskott-Aldrich Syndrome Protein Family/metabolism , Mice, TransgenicABSTRACT
Doxorubicin is a widely used chemotherapeutic agent that causes dose-dependent cardiotoxicity in a subset of treated patients, but the genetic determinants of this susceptibility are poorly understood. Here, we report that a noncanonical tumor suppressor activity of p53 prevents cardiac dysfunction in a mouse model induced by doxorubicin administered in divided low doses as in the clinics. While relatively preserved in wild-type (p53+/+ ) state, mice deficient in p53 (p53-/- ) developed left ventricular (LV) systolic dysfunction after doxorubicin treatment. This functional decline in p53-/- mice was associated with decreases in cardiac oxidative metabolism, mitochondrial mass, and mitochondrial genomic DNA (mtDNA) homeostasis. Notably, mice with homozygous knockin of the p53 R172H (p53172H/H ) mutation, which like p53-/- state lacks the prototypical tumor suppressor activities of p53 such as apoptosis but retains its mitochondrial biogenesis capacity, showed preservation of LV function and mitochondria after doxorubicin treatment. In contrast to p53-null state, wild-type and mutant p53 displayed distinct mechanisms of transactivating mitochondrial transcription factor A (TFAM) and p53-inducible ribonucleotide reductase 2 (p53R2), which are involved in mtDNA transcription and maintenance. Importantly, supplementing mice with a precursor of NAD+ prevented the mtDNA depletion and cardiac dysfunction. These findings suggest that loss of mtDNA contributes to cardiomyopathy pathogenesis induced by doxorubicin administered on a schedule simulating that in the clinics. Given a similar mtDNA protection role of p53 in doxorubicin-treated human induced pluripotent stem cell (iPSC)-derived cardiomyocytes, the mitochondrial markers associated with cardiomyopathy development observed in blood and skeletal muscle cells may have prognostic utility.
Subject(s)
Cardiotoxicity/metabolism , Cardiotoxicity/prevention & control , Doxorubicin/toxicity , Tumor Suppressor Protein p53/metabolism , Animals , Apoptosis/physiology , Cardiomyopathies/metabolism , DNA, Mitochondrial/genetics , DNA-Binding Proteins , Heart Diseases/metabolism , Humans , Induced Pluripotent Stem Cells/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mitochondria, Heart/metabolism , Mitochondrial Proteins , Mutation , Myocytes, Cardiac/metabolism , Organelle Biogenesis , Primary Cell Culture , Transcription Factors , Tumor Suppressor Protein p53/geneticsABSTRACT
Although exercise is linked with improved health, the specific molecular mechanisms underlying its various benefits require further clarification. Here we report that exercise increases the nuclear localization and activity of p53 by acutely down-regulating coiled-coil-helix-coiled-coil-helix domain 4 (CHCHD4), a carrier protein that mediates p53 import into the mitochondria. This response to exercise is lost in transgenic mice with constitutive expression of CHCHD4. Mechanistically, exercise-induced nuclear transcription factor FOXO3 binds to the CHCHD4 promoter and represses its expression, preventing the translocation of p53 to the mitochondria and thereby increasing p53 nuclear localization. The synergistic increase in nuclear p53 and FOXO3 by exercise can facilitate their known interaction in transactivating Sirtuin 1 (SIRT1), a NAD+-dependent histone deacetylase that mediates adaptation to various stresses. Thus, our results reveal one mechanism by which exercise could be involved in preventing cancer and potentially other diseases associated with aging.
Subject(s)
Cell Nucleus/metabolism , Forkhead Box Protein O3/metabolism , Mitochondrial Membrane Transport Proteins/metabolism , Physical Conditioning, Animal , Tumor Suppressor Protein p53/metabolism , Active Transport, Cell Nucleus , Animals , Cell Nucleus/genetics , Forkhead Box Protein O3/genetics , Humans , Mice , Mice, Knockout , Mitochondrial Membrane Transport Proteins/genetics , Response Elements , Sirtuin 1/genetics , Sirtuin 1/metabolism , Tumor Suppressor Protein p53/geneticsABSTRACT
There is growing evidence that alterations in metabolism may contribute to tumorigenesis. Here, we report on members of families with the Li-Fraumeni syndrome who carry germline mutations in TP53, the gene encoding the tumor-suppressor protein p53. As compared with family members who are not carriers and with healthy volunteers, family members with these mutations have increased oxidative phosphorylation of skeletal muscle. Basic experimental studies of tissue samples from patients with the Li-Fraumeni syndrome and a mouse model of the syndrome support this in vivo finding of increased mitochondrial function. These results suggest that p53 regulates bioenergetic homeostasis in humans. (Funded by the National Heart, Lung, and Blood Institute and the National Institutes of Health; ClinicalTrials.gov number, NCT00406445.).
Subject(s)
Energy Metabolism/genetics , Exercise/physiology , Genes, p53 , Li-Fraumeni Syndrome/metabolism , Mitochondria, Muscle/metabolism , Phosphocreatine/metabolism , Animals , Case-Control Studies , Disease Models, Animal , Female , Germ-Line Mutation , Heterozygote , Humans , Li-Fraumeni Syndrome/genetics , Male , Mice , Muscle, Skeletal/metabolism , Oxygen Consumption/genetics , Oxygen Consumption/physiology , Pilot Projects , Weight Lifting/physiologyABSTRACT
p53, a critical tumor suppressor, regulates mitochondrial respiration, but how a nuclear protein can orchestrate the function of an organelle encoded by two separate genomes, both of which require p53 for their integrity, remains unclear. Here we report that the mammalian homolog of the yeast mitochondrial disulfide relay protein Mia40 (CHCHD4) is necessary for the respiratory-dependent translocation of p53 into the mitochondria. In the setting of oxidative stress, increased CHCHD4 expression partitions p53 into the mitochondria and protects its genomic integrity while decreasing p53 nuclear localization and transcriptional activity. Conversely, decreased CHCHD4 expression prevents the mitochondrial translocation of p53 while augmenting its nuclear localization and activity. Thus, the mitochondrial disulfide relay system allows p53 to regulate two spatially segregated genomes depending on oxidative metabolic activity.
Subject(s)
Disulfides/metabolism , Mitochondria/metabolism , Mitochondrial Membrane Transport Proteins/metabolism , Tumor Suppressor Protein p53/metabolism , Animals , Blotting, Western , Cell Nucleus/metabolism , DNA Repair , DNA, Mitochondrial/genetics , DNA, Mitochondrial/metabolism , HCT116 Cells , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Microscopy, Confocal , Mitochondrial Membrane Transport Proteins/genetics , Mitochondrial Precursor Protein Import Complex Proteins , Mutation , Protein Binding , Protein Transport , RNA Interference , Tumor Suppressor Protein p53/geneticsABSTRACT
Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal types of cancer, and novel treatment regimens are direly needed. Epigenetic regulation contributes to the development of various cancer types, but its role in the development of and potential as a therapeutic target for PDAC remains underexplored. Here, we show that PRMT1 is highly expressed in murine and human pancreatic cancer and is essential for cancer cell proliferation and tumorigenesis. Deletion of PRMT1 delays pancreatic cancer development in a KRAS-dependent mouse model, and multi-omics analyses reveal that PRMT1 depletion leads to global changes in chromatin accessibility and transcription, resulting in reduced glycolysis and a decrease in tumorigenic capacity. Pharmacological inhibition of PRMT1 in combination with gemcitabine has a synergistic effect on pancreatic tumor growth in vitro and in vivo. Collectively, our findings implicate PRMT1 as a key regulator of pancreatic cancer development and a promising target for combination therapy.
Subject(s)
Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Animals , Humans , Mice , Carcinoma, Pancreatic Ductal/drug therapy , Carcinoma, Pancreatic Ductal/genetics , Cell Line, Tumor , Epigenesis, Genetic , Gemcitabine , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolism , Protein-Arginine N-Methyltransferases/therapeutic use , Repressor Proteins/genetics , Repressor Proteins/metabolismABSTRACT
Adipose tissues serve as an energy reservoir and endocrine organ, yet the mechanisms that coordinate these functions remain elusive. Here, we show that the transcriptional coregulators, YAP and TAZ, uncouple fat mass from leptin levels and regulate adipocyte plasticity to maintain metabolic homeostasis. Activating YAP/TAZ signalling in adipocytes by deletion of the upstream regulators Lats1 and Lats2 results in a profound reduction in fat mass by converting mature adipocytes into delipidated progenitor-like cells, but does not cause lipodystrophy-related metabolic dysfunction, due to a paradoxical increase in circulating leptin levels. Mechanistically, we demonstrate that YAP/TAZ-TEAD signalling upregulates leptin expression by directly binding to an upstream enhancer site of the leptin gene. We further show that YAP/TAZ activity is associated with, and functionally required for, leptin regulation during fasting and refeeding. These results suggest that adipocyte Hippo-YAP/TAZ signalling constitutes a nexus for coordinating adipose tissue lipid storage capacity and systemic energy balance through the regulation of adipocyte plasticity and leptin gene transcription.
Subject(s)
Adaptor Proteins, Signal Transducing , Adipocytes , Adipose Tissue , Energy Metabolism , Hippo Signaling Pathway , Leptin , Protein Serine-Threonine Kinases , Signal Transduction , YAP-Signaling Proteins , Animals , Leptin/metabolism , Protein Serine-Threonine Kinases/metabolism , Mice , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , YAP-Signaling Proteins/metabolism , Adipose Tissue/metabolism , Adipocytes/metabolism , Cell Cycle Proteins/metabolism , Cell Cycle Proteins/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Transcriptional Coactivator with PDZ-Binding Motif Proteins/metabolism , Phosphoproteins/metabolism , Phosphoproteins/genetics , Tumor Suppressor Proteins/metabolism , Tumor Suppressor Proteins/genetics , Trans-Activators/metabolism , Trans-Activators/geneticsABSTRACT
Zinc finger protein tristetraprolin (TTP) modulates macrophage inflammatory activity by destabilizing cytokine mRNAs. In this study, through a screen of TTP-bound mRNAs in activated human macrophages, we have identified CCL3 mRNA as the most abundantly bound TTP target mRNA and have characterized this interaction via conserved AU-rich elements. Compared to the wild-type cells, TTP(-/-) macrophages produced higher levels of LPS-induced CCL3. In addition, the plasma level of CCL3 in TTP(-/-) mice was markedly higher than that in wild-type mice. To determine the in vivo significance of TTP-regulated CCL3, we generated CCL3(-/-)TTP(-/-) double-knockout mice. Along with decreased proinflammatory cytokines in their paw joints, there were significant functional and histologic improvements in the inflammatory arthritis of TTP(-/-) mice when CCL3 was absent, although cachexia, reflecting systemic inflammation, was notably unaffected. Furthermore, the marked exacerbation of aortic plaque formation caused by TTP deficiency in the APOE(-/-) mouse model of atherosclerosis was also rescued by disrupting CCL3. Taken together, our data indicate that the interaction between TTP and CCL3 mRNA plays an important role in modulating localized inflammatory processes in tissues that are dissociated from the systemic manifestations of chronic inflammation.
Subject(s)
Chemokine CCL3/metabolism , Inflammation/metabolism , Macrophages/metabolism , Tristetraprolin/metabolism , Animals , Arthritis, Experimental/immunology , Arthritis, Experimental/metabolism , Base Sequence , Chemokine CCL3/genetics , Chemokine CCL3/immunology , Female , Humans , Immunoprecipitation , Inflammation/immunology , Macrophages/immunology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Molecular Sequence Data , RNA, Messenger/analysis , RNA, Small Interfering , Reverse Transcriptase Polymerase Chain Reaction , Transfection , Tristetraprolin/immunologyABSTRACT
Fucoidan, a sulfated polysaccharide extracted from brown seaweed, has been proposed to effectively treat and prevent various viral infections. However, the mechanisms behind its antiviral activity are not completely understood. We investigate here the global transcriptional changes in bone marrow-derived dendritic cells (BMDCs) using RNA-Seq technology. Through both analysis of differentially expressed genes (DEG) and gene set enrichment analysis (GSEA), we found that fucoidan-treated BMDCs were enriched in virus-specific response pathways, including that of SARS-CoV-2, as well as pathways associated with nucleic acid-sensing receptors (RLR, TLR, NLR, STING), and type I interferon (IFN) production. We show that these transcriptome changes are driven by well-known regulators of the inflammatory response against viruses, including IRF, NF-κB, and STAT family transcription factors. Furthermore, 435 of the 950 upregulated DEGs are classified as type I IFN-stimulated genes (ISGs). Flow cytometric analysis additionally showed that fucoidan increased MHCII, CD80, and CD40 surface markers in BMDCs, indicative of greater antigen presentation and co-stimulation functionality. Our current study suggests that fucoidan transcriptionally activates PRR signaling, type I IFN production and signaling, ISGs production, and DC maturation, highlighting a potential mechanism of fucoidan-induced antiviral activity.
Subject(s)
COVID-19 , Dendritic Cells , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Humans , Polysaccharides/metabolism , Polysaccharides/pharmacology , SARS-CoV-2ABSTRACT
RATIONALE: Exercise capacity is a physiological characteristic associated with protection from both cardiovascular and all-cause mortality. p53 regulates mitochondrial function and its deletion markedly diminishes exercise capacity, but the underlying genetic mechanism orchestrating this is unclear. Understanding the biology of how p53 improves exercise capacity may provide useful insights for improving both cardiovascular as well as general health. OBJECTIVE: The purpose of this study was to understand the genetic mechanism by which p53 regulates aerobic exercise capacity. METHODS AND RESULTS: Using a variety of physiological, metabolic, and molecular techniques, we further characterized maximum exercise capacity and the effects of training, measured various nonmitochondrial and mitochondrial determinants of exercise capacity, and examined putative regulators of mitochondrial biogenesis. As p53 did not affect baseline cardiac function or inotropic reserve, we focused on the involvement of skeletal muscle and now report a wider role for p53 in modulating skeletal muscle mitochondrial function. p53 interacts with Mitochondrial Transcription Factor A (TFAM), a nuclear-encoded gene important for mitochondrial DNA (mtDNA) transcription and maintenance, and regulates mtDNA content. The increased mtDNA in p53(+/+) compared to p53(-/-) mice was more marked in aerobic versus glycolytic skeletal muscle groups with no significant changes in cardiac tissue. These in vivo observations were further supported by in vitro studies showing overexpression of p53 in mouse myoblasts increases both TFAM and mtDNA levels whereas depletion of TFAM by shRNA decreases mtDNA content. CONCLUSIONS: Our current findings indicate that p53 promotes aerobic metabolism and exercise capacity by using different mitochondrial genes and mechanisms in a tissue-specific manner.
Subject(s)
DNA, Mitochondrial/metabolism , Exercise Tolerance , Mitochondria, Muscle/metabolism , Muscle, Skeletal/metabolism , Myoblasts, Skeletal/metabolism , Physical Exertion , Tumor Suppressor Protein p53/metabolism , Animals , Binding Sites , Cell Line , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Exercise Tolerance/genetics , Glycolysis/genetics , High Mobility Group Proteins/genetics , High Mobility Group Proteins/metabolism , Liver/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Muscle Contraction , Muscle Strength , Mutation , Myocardium/metabolism , Oxygen Consumption , RNA Interference , Response Elements , Swimming , Time Factors , Transduction, Genetic , Transfection , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/genetics , Up-Regulation , Ventricular Function, LeftABSTRACT
Rheumatoid arthritis (RA) is a common autoimmune disease characterized by immune cell infiltration of the synovium, leading to the loss of cartilage, bone, and joint function. Although regulatory T (Treg) cells are thought to modulate the initiation and progression of RA, a consensus has yet to be reached regarding the function and composition of Treg cells in RA patients. To address these discrepancies, we analyzed not only the total Treg frequency but also that of Treg subpopulations in the peripheral blood of RA patients and healthy controls by flow cytometry. We found that the total Treg population was not significantly different between RA and control subjects. However, the effector Treg cell subgroup, defined as CD45RA-CD25hi, showed markedly decreased frequency in RA patients. In addition, the total Treg population from RA patients showed a significant decline in the expression of CD25. Both the naïve and effector Treg subgroups also showed marked reduction of CD25 expression in RA patients compared to controls. These data suggest that the decreased frequency of effector Treg cells and overall reduction of CD25 expression in Treg cells in the peripheral blood may be evidence of altered Treg homeostasis associated with RA pathogenesis.
Subject(s)
Arthritis, Rheumatoid/blood , Arthritis, Rheumatoid/immunology , Interleukin-2 Receptor alpha Subunit/metabolism , T-Lymphocytes, Regulatory/immunology , Adult , Case-Control Studies , Humans , Lymphocyte CountABSTRACT
Germline mutations of TP53, which cause the cancer predisposition disorder Li-Fraumeni syndrome (LFS), can increase mitochondrial activity as well as fatty acid ß-oxidation (FAO) in mice. Increased fatty acid metabolism can promote cancer malignancy, but its specific contribution to tumorigenesis in LFS remains unclear. To investigate this, we crossed LFS mice carrying the p53 R172H knock-in mutation (p53172H/H , homolog of the human TP53 R175H LFS mutation) with myoglobin-knockout (MB-/- ) mice known to have decreased FAO. MB-/- p53172H/H double-mutant mice also showed mildly reduced FAO in thymus, a common site of T lymphoma development in LFS mice, in association with an approximately 40% improvement in cancer-free survival time. RNA sequencing profiling revealed that the p53 R172H mutation promotes mitochondrial metabolism and ribosome biogenesis, both of which are suppressed by the disruption of MB. The activation of ribosomal protein S6, involved in protein translation and implicated in cancer promotion, was also inhibited in the absence of MB. To further confirm the role of FAO in lymphomagenesis, mitochondrial FAO enzyme, carnitine palmitoyltransferase 2 (CPT2), was specifically disrupted in T cells of p53172H/H mice using a Cre-loxP-mediated strategy. The heterozygous knockout of CPT2 resulted in thymus FAO haploinsufficiency and an approximately 30% improvement in survival time, paralleling the antiproliferative signaling observed with MB disruption. Thus, this study demonstrates that moderating FAO in LFS can suppress tumorigenesis and improve cancer-free survival with potential implications for cancer prevention. PREVENTION RELEVANCE: Mildly inhibiting the increased fatty acid oxidation observed in a mouse model of Li-Fraumeni syndrome, a cancer predisposition disorder caused by inherited mutations of TP53, dampens aberrant pro-tumorigenic cell signaling and improves the survival time of these mice, thereby revealing a potential strategy for cancer prevention in patients.
Subject(s)
Carcinogenesis/metabolism , Carnitine O-Palmitoyltransferase/metabolism , Fatty Acids/metabolism , Li-Fraumeni Syndrome/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Carcinogenesis/genetics , Carnitine O-Palmitoyltransferase/genetics , Case-Control Studies , Cells, Cultured , Disease Models, Animal , Disease-Free Survival , Energy Metabolism , Female , Gene Knock-In Techniques , Genetic Predisposition to Disease , Germ-Line Mutation , Heterozygote , Humans , Li-Fraumeni Syndrome/complications , Li-Fraumeni Syndrome/genetics , Li-Fraumeni Syndrome/mortality , Male , Mice , Mice, Knockout , Middle Aged , Myoblasts , Myoglobin/genetics , Oxidation-Reduction , Primary Cell Culture , Prospective Studies , Tumor Suppressor Protein p53/genetics , Young AdultABSTRACT
Microbial adhesion is critical for parasitic infection and colonization of host cells. To study the host-parasite interaction in vitro, we established a flow cytometry-based assay to measure the adherence of Trichomonas vaginalis to epithelial cell line SiHa. SiHa cells and T. vaginalis were detected as clearly separated, quantifiable populations by flow cytometry. We found that T. vaginalis attached to SiHa cells as early as 30 min after infection and the binding remained stable up to several hours, allowing for analysis of drug treatment efficacy. Importantly, NADPH oxidase inhibitor DPI treatment induced the detachment of T. vaginalis from SiHa cells in a dose-dependent manner without affecting host cell viability. Thus, this study may provide an understanding for the potential development of therapies against T. vaginalis and other parasite infections.
ABSTRACT
Despite the advancements in vaccination research and practices, influenza viruses remain a global health concern. Inducing a robust immune response by vaccination is especially challenging in the elderly, the immunocompromised, and persons with chronic illnesses. Polysaccharides derived from food may act as a safe and readily accessible means to boost the immune system during vaccination. In this study, we investigated whether crude polysaccharides derived from carrot pomace (CPP) could stimulate innate immune cell function and promote influenza vaccine immunogenicity. In bone marrow-derived dendritic cells (BMDCs), CPP increased the fraction of CD11c+MHCII+ cells and the expression of co-stimulatory molecules CD40 and CD80, indicative of enhanced maturation and activation. Functionally, CPP-treated BMDCs promoted inflammatory cytokine production in splenic lymphocytes. In a mouse model of immunosuppression induced by cyclophosphamide, animals given CPP before and after an influenza vaccine challenge showed increased frequencies of dendritic cells and natural killer cells in the spleen, in addition to the recovery of vaccine-specific antibody titers. Moreover, innate myeloid cells in CPP-fed mice showed evidence of phenotypic modification via markedly enhanced interleukin(IL)-12 and interferon(IFN)-γ production in response to lipopolysaccharide(LPS) stimulation ex vivo. Our findings suggest that the administration of carrot pomace polysaccharides can significantly enhance the efficacy of influenza vaccination.
Subject(s)
Daucus carota/chemistry , Dendritic Cells/immunology , Immunogenicity, Vaccine/drug effects , Influenza Vaccines/immunology , Polysaccharides/pharmacology , Animals , Immunity, Innate/drug effects , Mice , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & controlABSTRACT
The physiological effects of the many germline mutations of TP53, encoding the tumor suppressor protein p53, are poorly understood. Here we report generating a p53 R178C knockin mouse modeling the human TP53 R181C mutation, which is notable for its prevalence and prior molecular characterization. Consistent with its weak cancer penetrance in humans, homozygous p53178C/C mice show a modest increase in tumorigenesis but, surprisingly, are lean with decreased body fat content. They display evidence of increased lipolysis and upregulation of fatty acid metabolism in their inguinal white adipose tissue (iWAT). Gene expression and chromatin immunoprecipitation sequencing (ChIP-seq) analyses show that the mutant p53 bound and transactivated Beta-3-Adrenergic Receptor (ADRB3), a gene that is known to promote lipolysis and is associated with obesity. This study reveals that a germline mutation of p53 can affect fat metabolism, which has been implicated in cancer development.
Subject(s)
Germ-Line Mutation/genetics , Lipolysis/genetics , Sequence Homology, Amino Acid , Tumor Suppressor Protein p53/genetics , 3T3-L1 Cells , Adipocytes/metabolism , Adipose Tissue, White/pathology , Animals , Base Sequence , Fatty Acids/blood , Gene Expression Regulation , Homozygote , Humans , Li-Fraumeni Syndrome/genetics , Metabolomics , Mice , Mice, Inbred C57BL , Phenotype , Principal Component Analysis , Receptors, Adrenergic, beta-3/genetics , Signal TransductionABSTRACT
Circulating monocytes and plaque macrophages mediate inflammation in the pathogenesis of atherosclerosis. We purified these cells from patients undergoing carotid endarterectomy for advanced atherosclerosis and examined their in vivo transcriptomes using the serial analysis of gene expression (SAGE) technique. We observed striking differences in transcriptional regulators as monocytes transformed into plaque macrophages in contrast to monocytes and lung macrophages from normal subjects. Consistent with its role in moderating inflammation, tristetraprolin (TTP, ZFP36) was among the most highly expressed macrophage transcriptional regulators. Interestingly, the mRNAs of a subset of the macrophage transcriptional regulators specifically interacted with TTP, revealing a network of genes that may be important in controlling macrophage inflammatory activity. Giving functional significance to this interaction, the knockdown of TTP increased both cognate macrophage gene mRNAs and inflammatory tumor necrosis factor protein release. In contrast, transient overexpression of TTP resulted in decreased levels of the same genes supporting its role in regulating macrophage gene expression. Together, our results indicate that the in vivo gene expression analyses of cells involved in pathogenesis can provide biological insights for functional studies with potential clinical implications.
Subject(s)
Carotid Artery Diseases/metabolism , Intracranial Arteriosclerosis/metabolism , Macrophages/metabolism , Transcription Factors/blood , Tristetraprolin/physiology , Aged , Carotid Artery Diseases/pathology , Cell Line , Female , Gene Library , Humans , Intracranial Arteriosclerosis/pathology , Macrophages/pathology , Male , Middle Aged , Monocytes/metabolism , RNA, Messenger/metabolism , RNA, Small Interfering/pharmacology , Transcription Factors/antagonists & inhibitors , Tristetraprolin/antagonists & inhibitors , Tristetraprolin/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Inheritance of germline mutations in the tumor suppressor gene TP53 causes Li-Fraumeni syndrome (LFS), a cancer predisposition disorder. The arginine to histidine substitution at amino acid position 337 of p53 (R337H) is a founder mutation highly prevalent in southern and southeastern Brazil and is considered an LFS mutation. Although this mutation is of significant clinical interest, its role in tumorigenesis using animal models has not been described. Here, we generate a knockin mouse model containing the homologous R337H mutation (mouse R334H). De novo tumorigenesis was not significantly increased in either heterozygous (p53334R/H ) or homozygous (p53334H/H ) p53 R334H knockin mice compared with wild-type mice. However, susceptibility to diethylnitrosamine (DEN)-induced liver carcinogenesis was increased in a mutant allele dose-dependent manner. In parallel, p53334H/H mice exposed to DEN exhibited increased DNA damage but decreased cell-cycle regulation in the liver. Oligomerization of p53, which is required for transactivation of target genes, was reduced in R334H liver, consistent with its decreased nuclear activity compared with wild-type. By modeling a TP53 mutation in mice that has relatively weak cancer penetrance, this study provides in vivo evidence that the human R337H mutation can compromise p53 activity and promote tumorigenesis.Significance: A germline mutation in the oligomerization domain of p53 decreases its transactivation potential and renders mice susceptible to carcinogen-induced liver tumorigenesis. Cancer Res; 78(18); 5375-83. ©2018 AACR.
Subject(s)
Carcinogenesis/genetics , Liver Neoplasms/pathology , Tumor Suppressor Protein p53/genetics , Alleles , Animals , Brazil , Cell Transformation, Neoplastic/genetics , DNA Damage , Fibroblasts/metabolism , Gene Knock-In Techniques , Genetic Predisposition to Disease , Germ-Line Mutation , Homozygote , Humans , Liver/metabolism , Liver Neoplasms/chemically induced , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Mutation , Transcriptional ActivationABSTRACT
Translational studies using genomic techniques in cardiovascular diseases are still in their infancy. Access to disease-associated cardiovascular tissues from patients has been a major impediment to progress in contrast to the diagnostic advances made by oncologists using gene expression on readily available tumor samples. Nonetheless, progress is being made for atherosclerosis by carefully designed experiments utilizing diseased tissue or surrogate specimens. This review details the rationale and findings of a study utilizing freshly isolated blood mononuclear cells from patients undergoing carotid endarterectomy due to atherosclerotic stenosis and from matched healthy subjects. By querying this cardiovascular tissue surrogate, the messenger RNA levels of the Finkel-Biskis-Jenkins osteosarcoma gene in circulating monocytes were found to correlate with atherosclerosis severity in patients and with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) therapy in healthy subjects. The major finding of this investigation is discussed in relation to observations from other human atherosclerosis gene expression studies. These distinct studies converge to demonstrate the unequivocal importance of inflammation in atherosclerosis. Although the clinical utility of the specific findings remains open, the identification of similar genes by different investigations serves to validate our report. They also provide us with insights into pathogenesis that may impact future translational applications.
Subject(s)
Atherosclerosis/genetics , Gene Expression Profiling/methods , Monocytes/metabolism , Atherosclerosis/blood , Biomarkers/blood , Humans , RNA, Messenger/blood , Ribosomal Proteins/genetics , Vasculitis/complications , Vasculitis/geneticsABSTRACT
Li-Fraumeni syndrome (LFS) is a cancer predisposition disorder caused by germline mutations in TP53 that can lead to increased mitochondrial metabolism in patients. However, the implications of altered mitochondrial function for tumorigenesis in LFS are unclear. Here, we have reported that genetic or pharmacologic disruption of mitochondrial respiration improves cancer-free survival in a mouse model of LFS that expresses mutant p53. Mechanistically, inhibition of mitochondrial function increased autophagy and decreased the aberrant proliferation signaling caused by mutant p53. In a pilot study, LFS patients treated with metformin exhibited decreases in mitochondrial activity concomitant with activation of antiproliferation signaling, thus reproducing the effects of disrupting mitochondrial function observed in LFS mice. These observations indicate that a commonly prescribed diabetic medicine can restrain mitochondrial metabolism and tumorigenesis in an LFS model, supporting its further consideration for cancer prevention in LFS patients.