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1.
Cell ; 173(3): 706-719.e13, 2018 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-29677514

RESUMO

Cytoplasmic FUS aggregates are a pathological hallmark in a subset of patients with frontotemporal dementia (FTD) or amyotrophic lateral sclerosis (ALS). A key step that is disrupted in these patients is nuclear import of FUS mediated by the import receptor Transportin/Karyopherin-ß2. In ALS-FUS patients, this is caused by mutations in the nuclear localization signal (NLS) of FUS that weaken Transportin binding. In FTD-FUS patients, Transportin is aggregated, and post-translational arginine methylation, which regulates the FUS-Transportin interaction, is lost. Here, we show that Transportin and arginine methylation have a crucial function beyond nuclear import-namely to suppress RGG/RG-driven phase separation and stress granule association of FUS. ALS-associated FUS-NLS mutations weaken the chaperone activity of Transportin and loss of FUS arginine methylation, as seen in FTD-FUS, promote phase separation, and stress granule partitioning of FUS. Our findings reveal two regulatory mechanisms of liquid-phase homeostasis that are disrupted in FUS-associated neurodegeneration.


Assuntos
Arginina/química , Proteína FUS de Ligação a RNA/química , beta Carioferinas/química , Transporte Ativo do Núcleo Celular , Motivos de Aminoácidos , Citoplasma/metabolismo , Metilação de DNA , DNA Complementar/metabolismo , Densitometria , Degeneração Lobar Frontotemporal/metabolismo , Células HeLa , Homeostase , Humanos , Carioferinas/química , Espectroscopia de Ressonância Magnética , Metilação , Chaperonas Moleculares/química , Mutação , Doenças Neurodegenerativas/metabolismo , Ligação Proteica , Domínios Proteicos
2.
Cell ; 169(1): 132-147.e16, 2017 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-28340339

RESUMO

The accumulation of irreparable cellular damage restricts healthspan after acute stress or natural aging. Senescent cells are thought to impair tissue function, and their genetic clearance can delay features of aging. Identifying how senescent cells avoid apoptosis allows for the prospective design of anti-senescence compounds to address whether homeostasis can also be restored. Here, we identify FOXO4 as a pivot in senescent cell viability. We designed a FOXO4 peptide that perturbs the FOXO4 interaction with p53. In senescent cells, this selectively causes p53 nuclear exclusion and cell-intrinsic apoptosis. Under conditions where it was well tolerated in vivo, this FOXO4 peptide neutralized doxorubicin-induced chemotoxicity. Moreover, it restored fitness, fur density, and renal function in both fast aging XpdTTD/TTD and naturally aged mice. Thus, therapeutic targeting of senescent cells is feasible under conditions where loss of health has already occurred, and in doing so tissue homeostasis can effectively be restored.


Assuntos
Envelhecimento/patologia , Antibióticos Antineoplásicos/efeitos adversos , Peptídeos Penetradores de Células/farmacologia , Doxorrubicina/efeitos adversos , Envelhecimento/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacologia , Apoptose , Proteínas de Ciclo Celular , Linhagem Celular , Sobrevivência Celular , Senescência Celular/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacologia , Feminino , Fibroblastos/citologia , Fatores de Transcrição Forkhead/química , Fatores de Transcrição Forkhead/metabolismo , Humanos , Corpos de Inclusão/efeitos dos fármacos , Corpos de Inclusão/metabolismo , Corpos de Inclusão/patologia , Rim/efeitos dos fármacos , Rim/fisiologia , Fígado/efeitos dos fármacos , Fígado/fisiologia , Masculino , Camundongos , Síndromes de Tricotiodistrofia/tratamento farmacológico , Proteína Supressora de Tumor p53/metabolismo
3.
Mol Cell ; 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38981483

RESUMO

Metabolic enzymes can adapt during energy stress, but the consequences of these adaptations remain understudied. Here, we discovered that hexokinase 1 (HK1), a key glycolytic enzyme, forms rings around mitochondria during energy stress. These HK1-rings constrict mitochondria at contact sites with the endoplasmic reticulum (ER) and mitochondrial dynamics protein (MiD51). HK1-rings prevent mitochondrial fission by displacing the dynamin-related protein 1 (Drp1) from mitochondrial fission factor (Mff) and mitochondrial fission 1 protein (Fis1). The disassembly of HK1-rings during energy restoration correlated with mitochondrial fission. Mechanistically, we identified that the lack of ATP and glucose-6-phosphate (G6P) promotes the formation of HK1-rings. Mutations that affect the formation of HK1-rings showed that HK1-rings rewire cellular metabolism toward increased TCA cycle activity. Our findings highlight that HK1 is an energy stress sensor that regulates the shape, connectivity, and metabolic activity of mitochondria. Thus, the formation of HK1-rings may affect mitochondrial function in energy-stress-related pathologies.

4.
Mol Cell ; 83(22): 4141-4157.e11, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37977121

RESUMO

Biomolecular condensates have emerged as a major organizational principle in the cell. However, the formation, maintenance, and dissolution of condensates are still poorly understood. Transcriptional machinery partitions into biomolecular condensates at key cell identity genes to activate these. Here, we report a specific perturbation of WNT-activated ß-catenin condensates that disrupts oncogenic signaling. We use a live-cell condensate imaging method in human cancer cells to discover FOXO and TCF-derived peptides that specifically inhibit ß-catenin condensate formation on DNA, perturb nuclear ß-catenin condensates in cells, and inhibit ß-catenin-driven transcriptional activation and colorectal cancer cell growth. We show that these peptides compete with homotypic intermolecular interactions that normally drive condensate formation. Using this framework, we derive short peptides that specifically perturb condensates and transcriptional activation of YAP and TAZ in the Hippo pathway. We propose a "monomer saturation" model in which short interacting peptides can be used to specifically inhibit condensate-associated transcription in disease.


Assuntos
Neoplasias , beta Catenina , Humanos , beta Catenina/genética , beta Catenina/metabolismo , Transdução de Sinais , Via de Sinalização Hippo , Peptídeos/genética
5.
Cell ; 156(5): 963-74, 2014 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-24581495

RESUMO

Protein folding in the cell relies on the orchestrated action of conserved families of molecular chaperones, the Hsp70 and Hsp90 systems. Hsp70 acts early and Hsp90 late in the folding path, yet the molecular basis of this timing is enigmatic, mainly because the substrate specificity of Hsp90 is poorly understood. Here, we obtained a structural model of Hsp90 in complex with its natural disease-associated substrate, the intrinsically disordered Tau protein. Hsp90 binds to a broad region in Tau that includes the aggregation-prone repeats. Complementarily, a 106-Å-long substrate-binding interface in Hsp90 enables many low-affinity contacts. This allows recognition of scattered hydrophobic residues in late folding intermediates that remain after early burial of the Hsp70 sites. Our model resolves the paradox of how Hsp90 specifically selects for late folding intermediates but also for some intrinsically disordered proteins-through the eyes of Hsp90 they look the same.


Assuntos
Proteínas tau/química , Doença de Alzheimer/tratamento farmacológico , Sequência de Aminoácidos , Proteínas de Choque Térmico HSP90/química , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Dobramento de Proteína , Espalhamento a Baixo Ângulo , Difração de Raios X , Proteínas tau/metabolismo
6.
Mol Cell ; 74(1): 73-87.e8, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30876805

RESUMO

The Hsp90 chaperone machinery in eukaryotes comprises a number of distinct accessory factors. Cns1 is one of the few essential co-chaperones in yeast, but its structure and function remained unknown. Here, we report the X-ray structure of the Cns1 fold and NMR studies on the partly disordered, essential segment of the protein. We demonstrate that Cns1 is important for maintaining translation elongation, specifically chaperoning the elongation factor eEF2. In this context, Cns1 interacts with the novel co-factor Hgh1 and forms a quaternary complex together with eEF2 and Hsp90. The in vivo folding and solubility of eEF2 depend on the presence of these proteins. Chaperoning of eEF2 by Cns1 is essential for yeast viability and requires a defined subset of the Hsp90 machinery as well as the identified eEF2 recruiting factor Hgh1.


Assuntos
Proteínas de Choque Térmico HSP90/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Chaperonas Moleculares/metabolismo , Elongação Traducional da Cadeia Peptídica , Fator 2 de Elongação de Peptídeos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Cristalografia por Raios X , Peptidil-Prolil Isomerase F , Ciclofilinas/genética , Ciclofilinas/metabolismo , Proteínas de Choque Térmico HSP90/química , Proteínas de Choque Térmico HSP90/genética , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/genética , Modelos Moleculares , Chaperonas Moleculares/química , Chaperonas Moleculares/genética , Ressonância Magnética Nuclear Biomolecular , Fator 2 de Elongação de Peptídeos/química , Fator 2 de Elongação de Peptídeos/genética , Ligação Proteica , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Relação Estrutura-Atividade
7.
Neuropsychobiology ; : 1-17, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38776887

RESUMO

INTRODUCTION: An increasing body of evidence suggests a strong relationship between gut health and mental state. Lately, a connection between butyrate-producing bacteria and sleep quality has been discussed. The PROVIT study, as a randomized, double-blind, 4-week, multispecies probiotic intervention study, aims at elucidating the potential interconnection between the gut's metabolome and the molecular clock in individuals with major depressive disorder (MDD). METHODS: The aim of the PROVIT-CLOCK study was to analyze changes in core clock gene expression during treatment with probiotic intervention versus placebo in fasting blood and the connection with the serum- and stool-metabolome in patients with MDD (n = 53). In addition to clinical assessments in the PROVIT study, metabolomics analyses with 1H nuclear magnetic resonance spectroscopy (stool and serum) and gene expression (RT-qPCR) analysis of the core clock genes ARNTL, PER3, CLOCK, TIMELESS, NR1D1 in peripheral blood mononuclear cells of fasting blood were performed. RESULTS: The gene expression levels of the clock gene CLOCK were significantly altered only in individuals receiving probiotic add-on treatment. TIMELESS and ARNTL gene expression changed significantly over the 4-week intervention period in both groups. Various positive and negative correlations between metabolites in serum/stool and core clock gene expression levels were observed. CONCLUSION: Changing the gut microbiome by probiotic treatment potentially influences CLOCK gene expression. The preliminary results of the PROVIT-CLOCK study indicate a possible interconnection between the gut microbiome and circadian rhythm potentially orchestrated by metabolites.

8.
Int J Mol Sci ; 25(9)2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38732266

RESUMO

Metabolic syndrome (MS) is a widespread disease in developed countries, accompanied, among others, by decreased adiponectin serum levels and perturbed lipoprotein metabolism. The associations between the serum levels of adiponectin and lipoproteins have been extensively studied in the past under healthy conditions, yet it remains unexplored whether the observed associations also exist in patients with MS. Therefore, in the present study, we analyzed the serum levels of lipoprotein subclasses using nuclear magnetic resonance spectroscopy and examined their associations with the serum levels of adiponectin in patients with MS in comparison with healthy volunteers (HVs). In the HVs, the serum levels of adiponectin were significantly negatively correlated with the serum levels of large buoyant-, very-low-density lipoprotein, and intermediate-density lipoprotein, as well as small dense low-density lipoprotein (LDL) and significantly positively correlated with large buoyant high-density lipoprotein (HDL). In patients with MS, however, adiponectin was only significantly correlated with the serum levels of phospholipids in total HDL and large buoyant LDL. As revealed through logistic regression and orthogonal partial least-squares discriminant analyses, high adiponectin serum levels were associated with low levels of small dense LDL and high levels of large buoyant HDL in the HVs as well as high levels of large buoyant LDL and total HDL in patients with MS. We conclude that the presence of MS weakens or abolishes the strong associations between adiponectin and the lipoprotein parameters observed in HVs and disturbs the complex interplay between adiponectin and lipoprotein metabolism.


Assuntos
Adiponectina , Lipoproteínas , Síndrome Metabólica , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adiponectina/sangue , Estudos de Casos e Controles , Voluntários Saudáveis , Lipoproteínas/sangue , Lipoproteínas HDL/sangue , Lipoproteínas LDL/sangue , Espectroscopia de Ressonância Magnética , Síndrome Metabólica/sangue
9.
J Biol Chem ; 298(9): 102287, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35868560

RESUMO

The tumor suppressor p53 is involved in the adaptation of hepatic metabolism to nutrient availability. Acute deletion of p53 in the mouse liver affects hepatic glucose and triglyceride metabolism. However, long-term adaptations upon the loss of hepatic p53 and its transcriptional regulators are unknown. Here we show that short-term, but not chronic, liver-specific deletion of p53 in mice reduces liver glycogen levels, and we implicate the transcription factor forkhead box O1 protein (FOXO1) in the regulation of p53 and its target genes. We demonstrate that acute p53 deletion prevents glycogen accumulation upon refeeding, whereas a chronic loss of p53 associates with a compensational activation of the glycogen synthesis pathway. Moreover, we identify fasting-activated FOXO1 as a repressor of p53 transcription in hepatocytes. We show that this repression is relieved by inactivation of FOXO1 by insulin, which likely mediates the upregulation of p53 expression upon refeeding. Strikingly, we find that high-fat diet-induced insulin resistance with persistent FOXO1 activation not only blunted the regulation of p53 but also the induction of p53 target genes like p21 during fasting, indicating overlapping effects of both FOXO1 and p53 on target gene expression in a context-dependent manner. Thus, we conclude that p53 acutely controls glycogen storage in the liver and is linked to insulin signaling via FOXO1, which has important implications for our understanding of the hepatic adaptation to nutrient availability.


Assuntos
Proteína Forkhead Box O1 , Homeostase , Glicogênio Hepático , Fígado , Proteína Supressora de Tumor p53 , Animais , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/metabolismo , Deleção de Genes , Glucose/metabolismo , Hepatócitos/metabolismo , Insulina/metabolismo , Fígado/metabolismo , Glicogênio Hepático/metabolismo , Camundongos , Triglicerídeos/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
10.
Breast Cancer Res ; 25(1): 119, 2023 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-37803350

RESUMO

BACKGROUND: Triple negative breast cancer (TNBC) is a particularly aggressive and difficult-to-treat subtype of breast cancer that requires the development of novel therapeutic strategies. To pave the way for such developments it is essential to characterize new molecular players in TNBC. MicroRNAs (miRNAs) constitute interesting candidates in this regard as they are frequently deregulated in cancer and contribute to numerous aspects of carcinogenesis. METHODS AND RESULTS: Here, we discovered that miR-4649-5p, a miRNA yet uncharacterized in breast cancer, is associated with better overall survival of TNBC patients. Ectopic upregulation of the otherwise very low endogenous expression levels of miR-4646-5p significantly decreased the growth, proliferation, and migration of TNBC cells. By performing whole transcriptome analysis and physical interaction assays, we were able to identify the phosphatidylinositol phosphate kinase PIP5K1C as a direct target of miR-4649-5p. Downregulation or pharmacologic inhibition of PIP5K1C phenocopied the growth-reducing effects of miR-4649-5p. PIP5K1C is known to play an important role in migration and cell adhesion, and we could furthermore confirm its impact on downstream PI3K/AKT signaling. Combinations of miR-4649-5p upregulation and PIP5K1C or AKT inhibition, using the pharmacologic inhibitors UNC3230 and capivasertib, respectively, showed additive growth-reducing effects in TNBC cells. CONCLUSION: In summary, miR-4649-5p exerts broad tumor-suppressive effects in TNBC and shows potential for combined therapeutic approaches targeting the PIP5K1C/PI3K/AKT signaling axis.


Assuntos
MicroRNAs , Neoplasias de Mama Triplo Negativas , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica
11.
J Transl Med ; 21(1): 54, 2023 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-36710341

RESUMO

BACKGROUND: Clear cell sarcomas (CCSs) are translocated aggressive malignancies, most commonly affecting young adults with a high incidence of metastases and a poor prognosis. Research into the disease is more feasible when adequate models are available. By establishing CCS cell lines from a primary and metastatic lesion and isolating healthy fibroblasts from the same patient, the in vivo process is accurately reflected and aspects of clinical multistep carcinogenesis recapitulated. METHODS: Isolated tumor cells and normal healthy skin fibroblasts from the same patient were compared in terms of growth behavior and morphological characteristics using light and electron microscopy. Tumorigenicity potential was determined by soft agar colony formation assay and in vivo xenograft applications. While genetic differences between the two lineages were examined by copy number alternation profiles, nuclear magnetic resonance spectroscopy determined arginine methylation as epigenetic features. Potential anti-tumor effects of a protein arginine N-methyltransferase type I (PRMT1) inhibitor were elicited in 2D and 3D cell culture experiments using cell viability and apoptosis assays. Statistical significance was calculated by one-way ANOVA and unpaired t-test. RESULTS: The two established CCS cell lines named MUG Lucifer prim and MUG Lucifer met showed differences in morphology, genetic and epigenetic data, reflecting the respective original tissue. The detailed cell line characterization especially in regards to the epigenetic domain allows investigation of new innovative therapies. Based on the epigenetic data, a PRMT1 inhibitor was used to demonstrate the targeted antitumor effect; normal tissue cells isolated and immortalized from the same patient were not affected with the IC50 used. CONCLUSIONS: MUG Lucifer prim, MUG Lucifer met and isolated and immortalized fibroblasts from the same patient represent an ideal in vitro model to explore the biology of CCS. Based on this cell culture model, novel therapies could be tested in the form of PRMT1 inhibitors, which drive tumor cells into apoptosis, but show no effect on fibroblasts, further supporting their potential as promising treatment options in the combat against CCS. The data substantiate the importance of tailored therapies in the advanced metastatic stage of CCS.


Assuntos
Sarcoma de Células Claras , Humanos , Sarcoma de Células Claras/genética , Sarcoma de Células Claras/metabolismo , Sarcoma de Células Claras/patologia , Linhagem Celular , Inibidores Enzimáticos , Arginina/genética , Arginina/metabolismo , Arginina/uso terapêutico , Epigênese Genética , Linhagem Celular Tumoral , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Proteína-Arginina N-Metiltransferases/uso terapêutico , Proteínas Repressoras/genética
12.
Cell Mol Life Sci ; 79(6): 326, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35635656

RESUMO

Signaling trough p53is a major cellular stress response mechanism and increases upon nutrient stresses such as starvation. Here, we show in a human hepatoma cell line that starvation leads to robust nuclear p53 stabilization. Using BioID, we determine the cytoplasmic p53 interaction network within the immediate-early starvation response and show that p53 is dissociated from several metabolic enzymes and the kinase PAK2 for which direct binding with the p53 DNA-binding domain was confirmed with NMR studies. Furthermore, proteomics after p53 immunoprecipitation (RIME) uncovered the nuclear interactome under prolonged starvation, where we confirmed the novel p53 interactors SORBS1 (insulin receptor signaling) and UGP2 (glycogen synthesis). Finally, transcriptomics after p53 re-expression revealed a distinct starvation-specific transcriptome response and suggested previously unknown nutrient-dependent p53 target genes. Together, our complementary approaches delineate several nodes of the p53 signaling cascade upon starvation, shedding new light on the mechanisms of p53 as nutrient stress sensor. Given the central role of p53 in cancer biology and the beneficial effects of fasting in cancer treatment, the identified interaction partners and networks could pinpoint novel pharmacologic targets to fine-tune p53 activity.


Assuntos
Transdução de Sinais , Proteína Supressora de Tumor p53 , Carcinoma Hepatocelular/metabolismo , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Humanos , Neoplasias Hepáticas/metabolismo , Nutrientes , Transdução de Sinais/fisiologia , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
13.
Proc Natl Acad Sci U S A ; 117(15): 8503-8514, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32234784

RESUMO

The specific interaction of importins with nuclear localization signals (NLSs) of cargo proteins not only mediates nuclear import but also, prevents their aberrant phase separation and stress granule recruitment in the cytoplasm. The importin Transportin-1 (TNPO1) plays a key role in the (patho-)physiology of both processes. Here, we report that both TNPO1 and Transportin-3 (TNPO3) recognize two nonclassical NLSs within the cold-inducible RNA-binding protein (CIRBP). Our biophysical investigations show that TNPO1 recognizes an arginine-glycine(-glycine) (RG/RGG)-rich region, whereas TNPO3 recognizes a region rich in arginine-serine-tyrosine (RSY) residues. These interactions regulate nuclear localization, phase separation, and stress granule recruitment of CIRBP in cells. The presence of both RG/RGG and RSY regions in numerous other RNA-binding proteins suggests that the interaction of TNPO1 and TNPO3 with these nonclassical NLSs may regulate the formation of membraneless organelles and subcellular localization of numerous proteins.


Assuntos
Núcleo Celular/metabolismo , Sinais de Localização Nuclear , Fragmentos de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , beta Carioferinas/metabolismo , Transporte Ativo do Núcleo Celular , Arginina/química , Arginina/metabolismo , Citoplasma/metabolismo , Glicina/química , Glicina/metabolismo , Células HeLa , Humanos , Fragmentos de Peptídeos/química , Ligação Proteica , Conformação Proteica , Proteínas de Ligação a RNA/química , Serina/química , Serina/metabolismo , Tirosina/química , Tirosina/metabolismo , beta Carioferinas/química
14.
Int J Mol Sci ; 24(13)2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37445857

RESUMO

The association between serum levels of endothelial lipase (EL) and the serum levels and composition of apolipoprotein B (apoB)-containing lipoproteins in healthy subjects and patients with metabolic syndrome (MS) remained unexplored. Therefore, in the present study, we determined the serum levels and lipid content of apoB-containing lipoproteins using nuclear magnetic resonance (NMR) spectroscopy and examined their association with EL serum levels in healthy volunteers (HVs) and MS patients. EL was significantly negatively correlated with the serum levels of cholesterol in large very low-density lipoprotein (VLDL) particles, as well as with total-cholesterol-, free-cholesterol-, triglyceride-, and phospholipid-contents of VLDL and intermediate-density lipoprotein particles in MS patients but not in HVs. In contrast, EL serum levels were significantly positively correlated with the serum levels of apoB, triglycerides, and phospholipids in large low-density lipoprotein particles in HVs but not in MS patients. EL serum levels as well as the serum levels and lipid content of the majority of apoB-containing lipoprotein subclasses were markedly different in MS patients compared with HVs. We conclude that EL serum levels are associated with the serum levels and lipid content of apoB-containing lipoproteins and that these associations are markedly affected by MS.


Assuntos
Síndrome Metabólica , Humanos , Voluntários Saudáveis , Lipoproteínas/metabolismo , Colesterol , Triglicerídeos , Lipoproteínas VLDL/metabolismo , Lipase , Apolipoproteínas B/metabolismo , Fosfolipídeos , Lipoproteínas LDL/metabolismo
15.
Int J Mol Sci ; 24(9)2023 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-37175716

RESUMO

Molecular diagnostics in healthcare relies increasingly on genomic and transcriptomic methodologies and requires appropriate tissue specimens from which nucleic acids (NA) of sufficiently high quality can be obtained. Besides the duration of ischemia and fixation type, NA quality depends on a variety of other pre-analytical parameters, such as storage conditions and duration. It has been discussed that the improper dehydration of tissue during processing influences the quality of NAs and the shelf life of fixed tissue. Here, we report on establishing a method for determining the amount of residual water in fixed, paraffin-embedded tissue (fixed by neutral buffered formalin or a non-crosslinking fixative) and its correlation to the performance of NAs in quantitative real-time polymerase chain reaction (qRT-PCR) analyses. The amount of residual water depended primarily on the fixative type and the dehydration protocol and, to a lesser extent, on storage conditions and time. Moreover, we found that these parameters were associated with the qRT-PCR performance of extracted NAs. Besides the cross-linking of NAs and the modification of nucleobases by formalin, the hydrolysis of NAs by residual water was found to contribute to reduced qRT-PCR performance. The negative effects of residual water on NA stability are not only important for the design and interpretation of research but must also be taken into account in clinical diagnostics where the reanalysis of archived tissue from a primary tumor may be required (e.g., after disease recurrence). We conclude that improving the shelf life of fixed tissue requires meticulous dehydration and dry storage to minimize the degradative influence of residual water on NAs.


Assuntos
Desidratação , Ácidos Nucleicos , Humanos , Fixadores , Fixação de Tecidos/métodos , Inclusão em Parafina/métodos , Umidade , Ácidos Nucleicos/genética , Formaldeído
16.
Int J Mol Sci ; 24(3)2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36768410

RESUMO

Metabolic syndrome (MS) is characterized by endothelial- and high-density lipoprotein (HDL) dysfunction and increased endothelial lipase (EL) serum levels. We examined the associations between EL serum levels, HDL (serum levels, lipid content, and function), and endothelial function in healthy volunteers (HV) and MS patients. Flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), serum levels of HDL subclasses (measured by nuclear magnetic resonance (NMR) spectroscopy), and EL serum levels differed significantly between HV and MS patients. The serum levels of triglycerides in large HDL particles were significantly positively correlated with FMD and NMD in HV, but not in MS patients. Cholesterol (C) and phospholipid (PL) contents of large HDL particles, calculated as HDL1-C/HDL1-apoA-I and HDL1-PL/HDL1-apoA-I, respectively, were significantly negatively correlated with FMD in HV, but not in MS patients. Cholesterol efflux capacity and arylesterase activity of HDL, as well as EL, were correlated with neither FMD nor NMD. EL was significantly negatively correlated with HDL-PL/HDL-apoA-I in HV, but not in MS patients, and with serum levels of small dense HDL containing apolipoprotein A-II in MS patients, but not in HV. We conclude that MS modulates the association between HDL and endothelial function, as well as between EL and HDL. HDL cholesterol efflux capacity and arylesterase activity, as well as EL serum levels, are not associated with endothelial function in HV or MS patients.


Assuntos
Lipoproteínas HDL , Síndrome Metabólica , Humanos , Lipoproteínas HDL/metabolismo , Apolipoproteína A-I , Voluntários Saudáveis , Lipase/metabolismo , Colesterol/metabolismo , HDL-Colesterol , Fosfolipídeos/metabolismo
17.
J Biol Chem ; 297(4): 101167, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487759

RESUMO

ToxR represents an essential transcription factor of Vibrio cholerae, which is involved in the regulation of multiple, mainly virulence associated genes. Its versatile functionality as activator, repressor or coactivator suggests a complex regulatory mechanism, whose clarification is essential for a better understanding of the virulence expression system of V. cholerae. Here, we provide structural information elucidating the organization and binding behavior of the cytoplasmic DNA-binding domain of ToxR (cToxR), containing a winged helix-turn-helix (wHTH) motif. Our analysis reveals unexpected structural features of this domain expanding our knowledge of a poorly defined subfamily of wHTH proteins. cToxR forms an extraordinary long α-loop and furthermore has an additional C-terminal beta strand, contacting the N-terminus and thus leading to a compact fold. The identification of the exact interactions between ToxR and DNA contributes to a deeper understanding of this regulatory process. Our findings not only show general binding of the soluble cytoplasmic domain of ToxR to DNA, but also indicate a higher affinity for the toxT motif. These results support the current theory of ToxR being a "DNA-catcher" to enable binding of the transcription factor TcpP and thus activation of virulence-associated toxT transcription. Although, TcpP and ToxR interaction is assumed to be crucial in the activation of the toxT genes, we could not detect an interaction event of their isolated cytoplasmic domains. We therefore conclude that other factors are needed to establish this protein-protein interaction, e.g., membrane attachment, the presence of their full-length proteins and/or other intermediary proteins that may facilitate binding.


Assuntos
Proteínas de Bactérias/química , Proteínas de Ligação a DNA/química , Fatores de Transcrição/química , Vibrio cholerae/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Sequências Hélice-Volta-Hélice , Domínios Proteicos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Vibrio cholerae/genética , Vibrio cholerae/metabolismo
18.
Mol Cell ; 53(6): 941-53, 2014 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-24613341

RESUMO

Hsp90 is the most abundant molecular chaperone in the eukaryotic cell. One of the most stringent clients is the glucocorticoid receptor (GR), whose in vivo function strictly depends on the interaction with the Hsp90 machinery. However, the molecular mechanism of this interaction has been elusive. Here we have reconstituted the interaction of Hsp90 with hormone-bound GR using purified components. Our biochemical and structural analyses define the binding site for GR on Hsp90 and reveal that binding of GR modulates the conformational cycle of Hsp90. FRET experiments demonstrate that a partially closed form of the Hsp90 dimer is the preferred conformation for interaction. Consistent with this, the conformational cycle of Hsp90 is decelerated, and its ATPase activity decreases. Hsp90 cochaperones differentially affect formation of the Hsp90-GR complex, serving as control elements for cycle progression and revealing an intricate interplay of client and cochaperones as molecular modulators of the Hsp90 machine.


Assuntos
Adenosina Trifosfatases/química , Regulação Fúngica da Expressão Gênica , Proteínas de Choque Térmico HSP90/química , Modelos Moleculares , Receptores de Glucocorticoides/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Estrutura Secundária de Proteína , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais
19.
Nucleic Acids Res ; 48(2): 949-961, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31754719

RESUMO

RNA aptamers-artificially created RNAs with high affinity and selectivity for their target ligand generated from random sequence pools-are versatile tools in the fields of biotechnology and medicine. On a more fundamental level, they also further our general understanding of RNA-ligand interactions e. g. in regard to the relationship between structural complexity and ligand affinity and specificity, RNA structure and RNA folding. Detailed structural knowledge on a wide range of aptamer-ligand complexes is required to further our understanding of RNA-ligand interactions. Here, we present the atomic resolution structure of an RNA-aptamer binding to the fluorescent xanthene dye tetramethylrhodamine. The high resolution structure, solved by NMR-spectroscopy in solution, reveals binding features both common and different from the binding mode of other aptamers with affinity for ligands carrying planar aromatic ring systems such as the malachite green aptamer which binds to the tetramethylrhodamine related dye malachite green or the flavin mononucleotide aptamer.


Assuntos
Aptâmeros de Nucleotídeos/química , Conformação de Ácido Nucleico , RNA/química , Rodaminas/química , Ligantes , Espectroscopia de Ressonância Magnética , Dobramento de RNA
20.
Molecules ; 27(15)2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35897932

RESUMO

Lipoproteins are important cardiovascular (CV) risk biomarkers. This study aimed to investigate the associations of lipoprotein subclasses with micro- and macrovascular biomarkers to better understand how these subclasses relate to atherosclerotic CV diseases. One hundred and fifty-eight serum samples from the EXAMIN AGE study, consisting of healthy individuals and CV risk patients, were analysed with nuclear magnetic resonance (NMR) spectroscopy to quantify lipoprotein subclasses. Microvascular health was quantified by measuring retinal arteriolar and venular diameters. Macrovascular health was quantified by measuring carotid-to-femoral pulse wave velocity (PWV). Nineteen lipoprotein subclasses showed statistically significant associations with retinal vessel diameters and nine with PWV. These lipoprotein subclasses together explained up to 26% of variation (R2 = 0.26, F(29,121) = 2.80, p < 0.001) in micro- and 12% (R2 = 0.12, F(29,124) = 1.70, p = 0.025) of variation in macrovascular health. High-density (HDL-C) and low-density lipoprotein cholesterol (LDL-C) as well as triglycerides together explained up to 13% (R2 = 0.13, F(3143) = 8.42, p < 0.001) of micro- and 8% (R2 = 0.08, F(3145) = 5.46, p = 0.001) of macrovascular variation. Lipoprotein subclasses seem to reflect micro- and macrovascular end organ damage more precisely as compared to only measuring HDL-C, LDL-C and triglycerides. Further studies are needed to analyse how the additional quantification of lipoprotein subclasses can improve CV risk stratification and CV disease prediction.


Assuntos
Lipoproteínas , Análise de Onda de Pulso , Biomarcadores , LDL-Colesterol , Humanos , Lipoproteínas LDL , Triglicerídeos
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