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BACKGROUND: Sepsis presents a challenge due to its complex immune responses, where balance between inflammation and anti-inflammation is critical for survival. Glucocorticoid-induced leucine zipper (GILZ) is key protein in achieving this balance, suppressing inflammation and mediating glucocorticoid response. This study aims to investigate GILZ transcript variants in sepsis patients and explore their potential for patient stratification and optimizing glucocorticoid therapy. METHODS: Sepsis patients meeting the criteria outlined in Sepsis-3 were enrolled, and RNA was isolated from whole blood samples. Quantitative mRNA expression of GILZ transcript variants in both sepsis patient samples (n = 121) and the monocytic U937 cell line (n = 3), treated with hydrocortisone and lipopolysaccharides, was assessed using quantitative PCR (qPCR). RESULTS: Elevated expression of GILZ transcript variant 1 (GILZ TV 1) serves as a marker for heightened 30-day mortality in septic patients. Increased levels of GILZ TV 1 within the initial day of sepsis onset are associated with a 2.2-[95% CI 1.2-4.3] fold rise in mortality, escalating to an 8.5-[95% CI 2.0-36.4] fold increase by day eight. GILZ TV1 expression is enhanced by glucocorticoids in cell culture but remains unaffected by inflammatory stimuli such as LPS. In septic patients, GILZ TV 1 expression increases over the course of sepsis and in response to hydrocortisone treatment. Furthermore, a high expression ratio of transcript variant 1 relative to all GILZ mRNA TVs correlates with a 2.3-fold higher mortality rate in patients receiving hydrocortisone treatment. CONCLUSION: High expression of GILZ TV 1 is associated with a higher 30-day sepsis mortality rate. Moreover, a high expression ratio of GILZ TV 1 relative to all GILZ transcript variants is a parameter for identifying patient subgroups in which hydrocortisone may be contraindicated.
Assuntos
Hidrocortisona , Sepse , Fatores de Transcrição , Humanos , Sepse/tratamento farmacológico , Sepse/mortalidade , Hidrocortisona/uso terapêutico , Hidrocortisona/administração & dosagem , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Fatores de Transcrição/análise , Fatores de Transcrição/genéticaRESUMO
The variability in mortality in sepsis could be a consequence of genetic variability. The glucocorticoid system and the intermediate TSC22D3 gene product-glucocorticoid-induced leucine zipper-are clinically relevant in sepsis, which is why this study aimed to clarify whether TSC22D3 gene polymorphisms contribute to the variance in sepsis mortality. Blood samples for DNA extraction were obtained from 455 patients with a sepsis diagnosis according to the Sepsis-III criteria and from 73 control subjects. A SNP TaqMan assay was used to detect single-nucleotide polymorphisms (SNPs) in the TSC22D3 gene. Statistical and graphical analyses were performed using the SPSS Statistics and GraphPad Prism software. C-allele carriers of rs3747406 have a 2.07-fold higher mortality rate when the sequential organ failure assessment (SOFA) score is higher than eight. In a multivariate COX regression model, the SNP rs3747406 with a SOFA score ≥ 8 was found to be an independent risk factor for 30-day survival in sepsis. The HR was calculated to be 2.12, with a p-value of 0.011. The wild-type allele was present in four out of six SNPs in our cohort. The promoter of TSC22D3 was found to be highly conserved. However, we discovered that the C-allele of rs3747406 poses a risk for sepsis mortality for SOFA Scores higher than 6.
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Escores de Disfunção Orgânica , Sepse , Humanos , Glucocorticoides , Zíper de Leucina , Polimorfismo de Nucleotídeo Único , Sepse/genéticaRESUMO
Sepsis is a common life-threatening disease caused by dysregulated immune response and metabolic acidosis which lead to organ failure. An abnormal expression of aquaporins plays an important role in organ failure. Additionally, genetic variants in aquaporins impact on the outcome in sepsis. Thus, we investigated the polymorphism (rs17553719) and expression of aquaporin-3 (AQP3) and correlated these measurements with the survival of sepsis patients. Accordingly, we collected blood samples on several days (plus clinical data) from 265 sepsis patients who stayed in different ICUs in Germany. Serum plasma, DNA, and RNA were then separated to detect the promotor genotypes of AQP3 mRNA expression of AQP3 and several cytokines. The results showed that the homozygote CC genotype exhibited a significant decrease in 30-day survival (38.9%) compared to the CT (66.15%) and TT genotypes (76.3%) (p = 0.003). Moreover, AQP3 mRNA expression was significantly higher and nearly doubled in the CC compared to the CT (p = 0.0044) and TT genotypes (p = 0.018) on the day of study inclusion. This was accompanied by an increased IL-33 concentration in the CC genotype (day 0: p = 0.0026 and day 3: p = 0.008). In summary, the C allele of the AQP3 polymorphism (rs17553719) shows an association with increased AQP3 expression and IL-33 concentration accompanied by decreased survival in patients with sepsis.
Assuntos
Aquaporinas , Sepse , Humanos , Aquaporina 3/genética , Aquaporinas/genética , Aquaporinas/metabolismo , Genótipo , Interleucina-33/genética , Interleucina-33/metabolismo , RNA Mensageiro/metabolismo , Sepse/genética , Sepse/metabolismoRESUMO
Sepsis involves an immunological systemic response to a microbial pathogenic insult, leading to a cascade of interconnected biochemical, cellular, and organ-organ interaction networks. Potential drug targets can depict aquaporins, as they are involved in immunological processes. In immune cells, AQP3 and AQP9 are of special interest. In this study, we tested the hypothesis that these aquaporins are expressed in the blood cells of septic patients and impact sepsis survival. Clinical data, routine laboratory parameters, and blood samples from septic patients were analyzed on day 1 and day 8 after sepsis diagnosis. AQP expression and cytokine serum concentrations were measured. AQP3 mRNA expression increased over the duration of sepsis and was correlated with lymphocyte count. High AQP3 expression was associated with increased survival. In contrast, AQP9 expression was not altered during sepsis and was correlated with neutrophil count, and low levels of AQP9 were associated with increased survival. Furthermore, AQP9 expression was an independent risk factor for sepsis lethality. In conclusion, AQP3 and AQP9 may play contrary roles in the pathophysiology of sepsis, and these results suggest that AQP9 may be a novel drug target in sepsis and, concurrently, a valuable biomarker of the disease.
Assuntos
Aquaporinas , Sepse , Humanos , Aquaporina 3/genética , Aquaporina 3/metabolismo , Aquaporinas/genética , Aquaporinas/metabolismo , Sepse/genéticaRESUMO
Hemoadsorption with CytoSorb® becomes increasingly established in treatment of various, predominantly inflammation-associated diseases. In septic shock, results suggest improvements in hemodynamics and organ function. However, little is known about the in vivo adsorption properties for various antibiotics. We present the case of a 61-year-old female patient with known Ulrich Turner syndrome who treated supportively with CytoSorb® and with linezolid due to a Staphylococcus epidermidis bloodstream infection as part of her intensive care treatment for septic shock. After establishment of a new adsorber, 600 mg of linezolid administered over 1 h. Linezolid levels measured before adsorber inlet (cpre) and after adsorber outlet (cpost) at 0, 15, 60, 120 and 480 min after starting infusion. Out of the ten samples, only the cpre samples 60 min (3.25 mg/l) and 120 min (4.7 mg/l) showed sufficiently high linezolid levels (therapeutic range 3-9 mg/l). After 480 min, cpre decreased to 2.8 mg/l, cpost increased to 1.85 mg/l, and thus clearance decreased to 67.86 ml/min (from 200 ml/min at 60 min), with greatly reduced adsorption capacity of CytoSorb® after 8 h. A loading dose (additional 600 mg) would have been urgently needed. Linezolid therapy under hemadsorption with CytoSorb® requires a clear indication and close monitoring of levels to avoid underdosing.
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Sepse , Choque Séptico , Antibacterianos , Citocinas , Feminino , Humanos , Linezolida , Pessoa de Meia-Idade , Choque Séptico/tratamento farmacológicoRESUMO
The "normal" immune response to an insult triggers a highly regulated response determined by the interaction of various immunocompetent cells with pro- and anti-inflammatory cytokines. Under pathologic conditions, the massive elevation of cytokine levels ("cytokine storm") could not be controlled until the recent development of hemoadsorption devices that are able to extract a variety of different DAMPs, PAMPs, and metabolic products from the blood. CytoSorb® has been approved for adjunctive sepsis therapy since 2011. This review aims to summarize theoretical knowledge, in vitro results, and clinical findings to provide the clinician with pragmatic guidance for daily practice. English-language and peer-reviewed literature identified by a selective literature search in PubMed and published between January 2016 and May 2021 was included. Hemoadsorption can be used successfully as adjunct to a complex therapeutic regimen for various conditions. To the contrary, this nonspecific intervention may potentially worsen patient outcomes in complex immunological processes. CytoSorb® therapy appears to be safe and useful in various diseases (e.g., rhabdomyolysis, liver failure, or intoxications) as well as in septic shock or cytokine release syndrome, although a conclusive assessment of treatment benefit is not possible and no survival benefit has yet been demonstrated in randomized controlled trials.
Assuntos
Síndrome da Liberação de Citocina/terapia , Citocinas , Choque Séptico/terapia , Animais , Antibacterianos , COVID-19 , Síndrome da Liberação de Citocina/imunologia , Citocinas/sangue , Bases de Dados Factuais , Humanos , Hiperbilirrubinemia , Rabdomiólise , Sepse/sangue , Choque Séptico/imunologiaRESUMO
PURPOSE: Liver function of intensive care patients is routinely monitored by static blood pathology. For specific indications, liver specific cytochrome activity may be measured by the commercially available maximum liver function capacity (LiMAx) test via quantification of the cytochrome P450 1A2 (CYP1A2) dependent C-methacetin metabolism. Sedation with the volatile anesthetic isoflurane was suspected to abrogate the correlation of LiMAx test with global liver function. We hypothesized that isoflurane has a CYP1A2-activity and LiMAx test result decreasing effect. METHODS: In this monocentric, observational clinical study previously liver healthy intensive care patients, scheduled to be changed from propofol to isoflurane sedation, were enrolled. LiMAx testing was done before, during and after termination of isoflurane sedation. RESULTS: The mean LiMAx value decreased during isoflurane sedation. Septic patients (n = 11) exhibited lower LiMAx values compared to non-septic patients (n = 11) at all time points. LiMAx values decreased with isoflurane from 140 ± 82 to 30 ± 34 µg kg-1 h-1 in the septic group and from 253 ± 92 to 147 ± 131 µg kg-1 h-1 in the non-septic group while laboratory markers did not imply significant hepatic impairment. Lactate increased during isoflurane inhalation without clinical consequence. CONCLUSION: Sepsis and isoflurane have independently demonstrated an effect on reducing the hepatic CYP1A2-activity. A network model was constructed that could explain the mechanism through the influence of isoflurane on hypoxia inducible factor (HIF-1α) by upregulation of the hypoxia-inducible pathway and the downregulation of CYP1A2-activity via the ligand-inducible pathway. Thus, the increased anaerobic metabolism may result in lactate accumulation. The influence of isoflurane sedation on the validated correlation of global liver function with CYP1A2-activity measured by LiMAx testing needs to be investigated in more detail.
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BACKGROUND: Sepsis is often associated with liver dysfunction, which is an indicator of poor outcomes. Specific diagnostic tools that detect hepatic dysfunction in its early stages are scarce. So far, the immune modulatory effects of hemoadsorption with CytoSorb® on liver function are unclear. METHOD: We assessed the hepatic function by using the dynamic LiMAx® test and biochemical parameters in 21 patients with sepsis or septic shock receiving CytoSorb® in a prospective, observational study. Points of measurement: T1: diagnosis of sepsis or septic shock; T2 and T3: 24 h and 48 h after the start of CytoSorb®; T4: 24 h after termination of CytoSorb®. RESULTS: The hepatic biotransformation capacity measured by LiMAx® was severely impaired in up to 95 % of patients. Despite a rapid shock reversal under CytoSorb®, a significant improvement in LiMAx® values appeared from T3 to T4. This decline and recovery of liver function were not reflected by common parameters of hepatic metabolism that remained mostly within the normal range. CONCLUSIONS: Hepatic dysfunction can effectively and safely be diagnosed with LiMAx® in ventilated ICU patients under CytoSorb®. Various static liver parameters are of limited use since they do not adequately reflect hepatic dysfunction and impaired hepatic metabolism.
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Gut ischemia is a frequent but underdiagnosed complication, especially in critically ill intensive care patients, and represents a special diagnostic challenge that can only be solved in an interdisciplinary manner. We report a case of a 54-year-old woman with acute mesenteric ischemia (AMI) as a cause of septic shock diagnosed by intravital microscopy (IVM) 2 days before visible necrotic changes in a multimodality approach. We show that intravital microscopy can be a serious alternative for the early diagnosis of mesenteric ischemia in the hands of the skilled. We use this case to discuss the value and clinical perspective of IVM in the intensive care setting.
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The COP9 signalosome complex (CSN) is a crucial regulator of ubiquitin ligases. Defects in CSN result in embryonic impairment and death in higher eukaryotes, whereas the filamentous fungus Aspergillus nidulans survives without CSN, but is unable to complete sexual development. We investigated overall impact of CSN activity on A. nidulans cells by combined transcriptome, proteome and metabolome analysis. Absence of csn5/csnE affects transcription of at least 15% of genes during development, including numerous oxidoreductases. csnE deletion leads to changes in the fungal proteome indicating impaired redox regulation and hypersensitivity to oxidative stress. CSN promotes the formation of asexual spores by regulating developmental hormones produced by PpoA and PpoC dioxygenases. We identify more than 100 metabolites, including orsellinic acid derivatives, accumulating preferentially in the csnE mutant. We also show that CSN is required to activate glucanases and other cell wall recycling enzymes during development. These findings suggest a dual role for CSN during development: it is required early for protection against oxidative stress and hormone regulation and is later essential for control of the secondary metabolism and cell wall rearrangement.
Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/metabolismo , Parede Celular/metabolismo , Regulação Fúngica da Expressão Gênica , Hormônios/metabolismo , Complexos Multiproteicos/metabolismo , Estresse Oxidativo , Peptídeo Hidrolases/metabolismo , Transdução de Sinais , Aspergillus nidulans/genética , Complexo do Signalossomo COP9 , Proteínas Fúngicas/genética , Deleção de Genes , Perfilação da Expressão Gênica , Metaboloma , Complexos Multiproteicos/genética , Peptídeo Hidrolases/genética , ProteomaRESUMO
BACKGROUND AND PURPOSE: Hemoadsorption with CytoSorb® offers a possible therapeutic approach in septic shock, but modes of application and dosing are still undetermined. MATERIALS AND METHODS: Data from surgical patients with septic shock, treated with hemoadsorption adjunctive to renal replacement therapy were analyzed retrospectively. The 28-day mortality was compared to predicted mortality. RESULTS: In 70 patients (70.6 ± 13.3 years), hemoadsorption was applied for 85.6 ± 53.8 h. The APACHE ll (30.2 ± 6.3) calculated to a predicted mortality of 73.3%, while the observed mortality was significantly lower (50%, p < 0.05). The amount of blood purified was higher in survivors than in non-survivors (8.5 ± 4.4 vs. 6.1 ± 3.6 l/kgBW, p = 0.017). We identified three clusters of <6 l/kgBW, 6-13 l/kgBW and ≥ 13 l/kgBW with a linear dose-response relation between blood purification volume and survival, which was best in the highest volume cluster (83.3%; p = 0.045). CONCLUSIONS: The application of CytoSorb® seems to be effective in various conditions of septic shock. In a cohort of most severely ill patients the observed mortality was lower than predicted and decreased linearly with blood purification volumes inadvertently exceeding 6 l/kg BW. These results suggest that hemoadsorption might improve survival provided that the applied dose is high enough.
Assuntos
Choque Séptico , APACHE , Citocinas , Humanos , Estudos Retrospectivos , Choque Séptico/terapiaRESUMO
LiMAx 13C-methacetin breath test results should be interpreted with caution in patients sedated with isoflurane.
RESUMO
BACKGROUND: Sepsis and septic shock are still life-threatening diseases with a high mortality rate. We report a complex case of peritonitis with pericarditis and acute liver failure caused by septic shock. Potentially hepatotoxic antibiotic therapy levels were monitored using the liver maximum capacity (LiMAx®) test, and standard treatment was supplemented by adjunctive hemoadsorption with CytoSorb®. Case Presentation. The case features a 29-year-old woman with a history of Crohn's disease and cachexia. Peritonitis caused by Enterococcus faecium was diagnosed later due to an ileum perforation. The hematogenic spread led to pericarditis. In addition, sepsis-related acute liver failure complicated antimicrobial therapy further. The combination of standard therapy, anti-infective medication, and blood purification was associated with inflammation control, hemodynamic stabilization, and a concomitant decrease in vasopressor support. An efficient, sustained reduction in plasma bilirubin levels was achieved while maintaining liver function. CONCLUSIONS: This case shows how complex infectious diseases with an atypical infectious focus resulting in septic shock can be successfully treated. A combination of antimicrobial (tigecycline and caspofungin) and long-term adjunctive hemoadsorption therapy was administered while hepatotoxic antibiotic medication was monitored by liver function testing.
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BACKGROUND: Sepsis-treatment is one of the major challenges in our time. Especially fungal infections play an important role in patient's morbidity and mortality. In patients with septic shock, liver function is often significantly impaired and therefore also hepatic drug metabolism is altered. CASE PRESENTATION: We report about a 56-year-old man suffering from invasive fungal infection with multiorgan failure, after complicated medical history due to symptomatic infrarenal aortic aneurysm. On the first postoperative day, a CT scan was undertaken due to massive back pain showing renal infarction on both sides. As qualitative and quantitative renal function was impaired, hemodialysis was started immediately. Subsequently, the patient developed a compartment syndrome of the left leg and underwent fasciotomy. On admission day 7, the patient presented with hematochezia leading to colonoscopy. During this procedure, an ischemic colitis was observed. As conservative treatment failed, the patient underwent Hartmann's procedure due to progredient ischemia followed by a worsening of the clinical status due to sepsis. The patient suffered from an invasive fungal infection with Candida spp. and Aspergillus spp. Systemic antifungal treatment was initiated. Although azoles are considered first-line treatment in these cases we chose the echinocandin caspofungin for its presumed lower impact on liver function compared to azoles like voriconazole or Amphothericin B. However, caspofungin is also metabolised in the liver and can cause hepatotoxic effects. Therefore we measured metabolic liver function capacity using LiMAx®and adapted the patient's dose of caspofungin to the evaluated liver function capacity to achieve an effective and liver-protective level of the active drug. After complicated medical history with 15 weeks of hospital stay, the patient was discharged in general good condition. CONCLUSIONS: To our knowledge, this is the first report that relates antimycotic drug dosing to a functional liver test. We provide a new approach for sepsis treatment considering liver function capacity to optimize dosage of hepatically metabolised drugs with potential hepatotoxic effects.
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Aspergillus fumigatus is a medically important opportunistic pathogen and a major cause of respiratory allergy. The species has long been considered an asexual organism. However, genome analysis has revealed the presence of genes associated with sexual reproduction, including a MAT-2 high-mobility group mating-type gene and genes for pheromone production and detection (Galagan et al., personal communication; Nierman et al., personal communication). We now demonstrate that A. fumigatus has other key characteristics of a sexual species. We reveal the existence of isolates containing a complementary MAT-1 alpha box mating-type gene and show that the MAT locus has an idiomorph structure characteristic of heterothallic (obligate sexual outbreeding) fungi. Analysis of 290 worldwide clinical and environmental isolates with a multiplex-PCR assay revealed the presence of MAT1-1 and MAT1-2 genotypes in similar proportions (43% and 57%, respectively). Further population genetic analyses provided evidence of recombination across a global sampling and within North American and European subpopulations. We also show that mating-type, pheromone-precursor, and pheromone-receptor genes are expressed during mycelial growth. These results indicate that A. fumigatus has a recent evolutionary history of sexual recombination and might have the potential for sexual reproduction. The possible presence of a sexual cycle is highly significant for the population biology and disease management of the species.
Assuntos
Aspergillus fumigatus/genética , Aspergillus fumigatus/fisiologia , Genes Fúngicos/genética , Genes Fúngicos Tipo Acasalamento , Genoma Fúngico , Sexo , Sequência de Aminoácidos , Sequência de Bases , Primers do DNA , Componentes do Gene , Genética Populacional , Genômica/métodos , Repetições de Microssatélites/genética , Dados de Sequência Molecular , Polimorfismo de Fragmento de Restrição , Reprodução/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
The signalosome (CSN) is a conserved multiprotein complex involved in regulation of eukaryotic development and is also required to activate ribonucleotide reductase for DNA synthesis. In Aspergillus nidulans, csnD/csnE are key regulators of sexual development. Here, we investigated whether the csnD/csnE genes are involved in the DNA damage response in this fungus. The growth of the csnD/csnE deletion mutants was reduced by subinhibitory concentrations of hydroxyurea, camptothecin, 4-nitroquinoline oxide, and methyl methanesulfonate. A. nidulans increases csnD/csnE mRNA levels when it is challenged by different DNA-damaging agents. There is no significant transcriptional induction of the csnE promoter fused with lacZ gene in the presence of DNA-damaging agents, suggesting that increased mRNA accumulation is due to increased mRNA stability. Septation was not inhibited in the csnD/csnE deletion mutants while DeltauvsB DeltacsnE presented an increase in septation upon DNA damage caused by methyl methanesulfonate, suggesting that uvsB(ATR) and csnE genetically interact during checkpoint-dependent inhibition of septum formation. The double DeltacsnD/DeltacsnE DeltanpkA mutants were more sensitive to DNA-damaging agents than were the respective single mutants. Our results suggest that csnD/csnE genes are involved in the DNA damage response and that NpkA and UvsB(ATR) genetically interact with the signalosome.
Assuntos
Aspergillus nidulans/genética , Dano ao DNA/fisiologia , Reparo do DNA/genética , Genes Fúngicos , Complexos Multiproteicos/genética , Peptídeo Hidrolases/genética , Aspergillus nidulans/fisiologia , Complexo do Signalossomo COP9 , Reparo do DNA/fisiologia , RNA Mensageiro/metabolismo , Reprodução/genética , Ribonucleotídeo Redutases/biossíntese , Ribonucleotídeo Redutases/genéticaAssuntos
COVID-19 , Oxigenação por Membrana Extracorpórea , Hemoperfusão , Citocinas , Humanos , SARS-CoV-2RESUMO
Cand1 inhibits cullin RING ubiquitin ligases by binding unneddylated cullins. The Cand1 N-terminus blocks the cullin neddylation site, whereas the C-terminus inhibits cullin adaptor interaction. These Cand1 binding sites can be separated into two functional polypeptides which bind sequentially. C-terminal Cand1 can directly bind to unneddylated cullins in the nucleus without blocking the neddylation site. The smaller N-terminal Cand1 cannot bind to the cullin neddylation region without C-terminal Cand1. The separation of a single cand1 into two independent genes represents the in vivo situation of the fungus Aspergillus nidulans, where C-terminal Cand1 recruits smaller N-terminal Cand1 in the cytoplasm. Either deletion results in an identical developmental and secondary metabolism phenotype in fungi, which resembles csn mutants deficient in the COP9 signalosome (CSN) deneddylase. We propose a two-step Cand1 binding to unneddylated cullins which initiates at the adaptor binding site and subsequently blocks the neddylation site after CSN has left.
Assuntos
Aspergillus nidulans/metabolismo , Proteínas Culina/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fusão Gênica Artificial , Aspergillus nidulans/genética , Aspergillus nidulans/crescimento & desenvolvimento , Proteínas de Ciclo Celular/metabolismo , Núcleo Celular/metabolismo , Proteínas Culina/química , Proteínas Culina/genética , Citoplasma/metabolismo , Proteínas Fúngicas/química , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Ligação Proteica , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Fatores de Transcrição/química , Técnicas do Sistema de Duplo-Híbrido , Ubiquitinação , Ubiquitinas/metabolismoRESUMO
Fruit body formation in filamentous fungi is a complex and yet hardly understood process. We show here that protein turnover control is crucial for Aspergillus nidulans development. Deletion of genes encoding COP9 signalosome (CSN) subunits 1, 2, 4, or 5 resulted in identical blocks in fruit body formation. The CSN multiprotein complex controls ubiquitin-dependent protein degradation in eukaryotes. Six CSN subunits interacted in a yeast two-hybrid analysis, and the complete eight-subunit CSN was recruited by a functional tandem affinity purification tag fusion of subunit 5 (CsnE). The tagged CsnE was unable to recruit any CSN subunit in a strain deleted for subunit 1 or subunit 4. Mutations in the JAMM metalloprotease core of CsnE resulted in mutant phenotypes identical to those of csn deletion strains. We propose that a correctly assembled CSN including a functional JAMM links protein turnover to fungal sexual development.