Systemic inflammatory cytokine profiles in patients with gout during flare, intercritical and treat-to-target phases: TNFSF14 as new biomarker.

INTRODUCTION: Untreated gout is characterised by monosodium urate (MSU) crystal accumulation responsible for recurrent flares that are commonly separated by asymptomatic phases. Both phases are inflammatory conditions of variable intensity. Gout flares are self-limited inflammatory reactions involving multiple mediators. This study aimed to characterise the inflammatory profiles of gout at different phases. METHODS: Using the Olink targeted proteomics, levels of 92 inflammation-related proteins were measured in plasma samples of a prospective gout population (GOUTROS), collected at gout flare (T1), the intercritical phase (T2) and after reaching the target serum urate level under urate-lowering therapy (T3). Results were validated in an independent cohort (OLT1177-05) with plasmas collected at T1 and T2. Ex vivo and in vitro experiments were performed to assess the inflammatory properties of new biomarkers. RESULTS: In total, 21 inflammatory new biomarkers were differentially expressed during the three time-points of gout disease. The levels of four of these proteins (interleukin 6 (IL-6), colony-stimulating factor 1, vascular endothelial growth factor A and tumour necrosis factor superfamily 14 (TNFSF14)) were increased during gout flare in an independent cohort. IL-6 and TNFSF14 had the highest fold change in expression during T1 versus T2 or T3. TNFSF14 was produced at the inflamed joint and enhanced the inflammatory response induced by lipopolysaccharide and MSU crystal stimulation. Conversely, TNFSF14 blockade reduced the inflammatory response. Additionally, single nucleotide polymorphisms of TNFSF14 affected the ability of myeloid cells to produce inflammatory cytokines. CONCLUSION: Gout flare involves multiple inflammatory mediators that may be used as potential therapeutic targets.

Expression, Prognostic Value and Correlation with HPV Status of Hypoxia-Induced Markers in Sinonasal Squamous Cell Carcinoma.

(1) Background: In head and neck squamous cell carcinoma, tumor hypoxia has been associated with radio/chemoresistance and poor prognosis, whereas human papillomavirus (HPV)-positive status has a positive impact on treatment response and survival outcomes. The aim of this study was to evaluate the expression and the potential prognostic value of hypoxia-induced endogenous markers in patients treated for squamous cell carcinoma of the nasal cavity and paranasal sinuses (SNSCC), and their correlation with HPV status. (2) Methods: In this monocentric study, patients treated in a curative intent for a SNSCC were screened retrospectively. Protein expression of CA-IX, GLUT-1, VEGF, VEGF-R1, and HIF-1α was determined by immunohistochemical staining, scored, and then correlated with overall survival (OS) and locoregional recurrence free survival (LRRFS). HPV status was assessed and correlated with hypoxic markers. (3) Results: 40 patients were included. A strong expression of CA-IX, GLUT-1, VEGF, and VEGF-R1 was detected in 30%, 32.5%, 50%, and 37.5% of cases, respectively. HIF-1α was detected in 27.5% of cases. High CA-IX expression was associated in univariate analysis with poor OS (p = 0.035), but there was no significant association between GLUT-1, VEGF, VEGF-R1, and HIF-1α expression, and OS/LRRFS. There was no correlation found between HPV status and hypoxia-induced endogenous markers (all p > 0.05). (4) Conclusions: This study provides data on the expression of hypoxia-induced endogenous markers in patients treated for SNSCC and underlines the potential role of CA-IX as a prognostic biomarker for SNSCC.

Nanopore Discrimination of Coagulation Biomarker Derivatives and Characterization of a Post-Translational Modification.

One of the most important health challenges is the early and ongoing detection of disease for prevention, as well as personalized treatment management. Development of new sensitive analytical point-of-care tests are, therefore, necessary for direct biomarker detection from biofluids as critical tools to address the healthcare needs of an aging global population. Coagulation disorders associated with stroke, heart attack, or cancer are defined by an increased level of the fibrinopeptide A (FPA) biomarker, among others. This biomarker exists in more than one form: it can be post-translationally modified with a phosphate and also cleaved to form shorter peptides. Current assays are long and have difficulties in discriminating between these derivatives; hence, this is an underutilized biomarker for routine clinical practice. We use nanopore sensing to identify FPA, the phosphorylated FPA, and two derivatives. Each of these peptides is characterized by unique electrical signals for both dwell time and blockade level. We also show that the phosphorylated form of FPA can adopt two different conformations, each of which have different values for each electrical parameter. We were able to use these parameters to discriminate these peptides from a mix, thereby opening the way for the potential development of new point-of-care tests.

Circulating Tumor Cells in Cancer Diagnostics and Prognostics by Single-Molecule and Single-Cell Characterization.

Circulating tumor cells (CTCs) represent an interesting source of biomarkers for diagnosis, prognosis, and the prediction of cancer recurrence, yet while they are extensively studied in oncobiology research, their diagnostic utility has not yet been demonstrated and validated. Their scarcity in human biological fluids impedes the identification of dangerous CTC subpopulations that may promote metastatic dissemination. In this Perspective, we discuss promising techniques that could be used for the identification of these metastatic cells. We first describe methods for isolating patient-derived CTCs and then the use of 3D biomimetic matrixes in their amplification and analysis, followed by methods for further CTC analyses at the single-cell and single-molecule levels. Finally, we discuss how the elucidation of mechanical and morphological properties using techniques such as atomic force microscopy and molecular biomarker identification using nanopore-based detection could be combined in the future to provide patients and their healthcare providers with a more accurate diagnosis.

Surgical Management of Sinonasal Cancers: A Comprehensive Review.

Surgery plays an important role in the treatment of sinonasal cancer. Many surgical approaches have been described, including open, endoscopic, or combined approaches. The choice is based on several criteria: general criteria related to the oncological results and morbidity of each technique, specific criteria related to the tumor (tumor extensions, tumor pathology), the patient, or the surgeon himself. The aims of this review are (i) to provide a complete overview of the surgical techniques available for the management of sinonasal malignant tumors, with a special focus on recent developments in the field of transnasal endoscopic surgery; (ii) to summarize the criteria that lead to the choice of one technique over another. In particular, the oncological outcomes, the morbidity of the different techniques, and the specificities of each histologic subtype will be discussed based on a comprehensive literature review.

Author Correction: Loss of MTX2 causes mandibuloacral dysplasia and links mitochondrial dysfunction to altered nuclear morphology.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Loss of MTX2 causes mandibuloacral dysplasia and links mitochondrial dysfunction to altered nuclear morphology.

Mandibuloacral dysplasia syndromes are mainly due to recessive LMNA or ZMPSTE24 mutations, with cardinal nuclear morphological abnormalities and dysfunction. We report five homozygous null mutations in MTX2, encoding Metaxin-2 (MTX2), an outer mitochondrial membrane protein, in patients presenting with a severe laminopathy-like mandibuloacral dysplasia characterized by growth retardation, bone resorption, arterial calcification, renal glomerulosclerosis and severe hypertension. Loss of MTX2 in patients' primary fibroblasts leads to loss of Metaxin-1 (MTX1) and mitochondrial dysfunction, including network fragmentation and oxidative phosphorylation impairment. Furthermore, patients' fibroblasts are resistant to induced apoptosis, leading to increased cell senescence and mitophagy and reduced proliferation. Interestingly, secondary nuclear morphological defects are observed in both MTX2-mutant fibroblasts and mtx-2-depleted C. elegans. We thus report the identification of a severe premature aging syndrome revealing an unsuspected link between mitochondrial composition and function and nuclear morphology, establishing a pathophysiological link with premature aging laminopathies and likely explaining common clinical features.

Monocytopenia, monocyte morphological anomalies and hyperinflammation characterise severe COVID-19 in type 2 diabetes.

Early in the COVID-19 pandemic, type 2 diabetes (T2D) was marked as a risk factor for severe disease and mortality. Inflammation is central to the aetiology of both conditions where variations in immune responses can mitigate or aggravate disease course. Identifying at-risk groups based on immunoinflammatory signatures is valuable in directing personalised care and developing potential targets for precision therapy. This observational study characterised immunophenotypic variation associated with COVID-19 severity in T2D. Broad-spectrum immunophenotyping quantified 15 leucocyte populations in peripheral circulation from a cohort of 45 hospitalised COVID-19 patients with and without T2D. Lymphocytopenia and specific loss of cytotoxic CD8+ lymphocytes were associated with severe COVID-19 and requirement for intensive care in both non-diabetic and T2D patients. A morphological anomaly of increased monocyte size and monocytopenia restricted to classical CD14Hi CD16- monocytes was specifically associated with severe COVID-19 in patients with T2D requiring intensive care. Increased expression of inflammatory markers reminiscent of the type 1 interferon pathway (IL6, IL8, CCL2, INFB1) underlaid the immunophenotype associated with T2D. These immunophenotypic and hyperinflammatory changes may contribute to increased voracity of COVID-19 in T2D. These findings allow precise identification of T2D patients with severe COVID-19 as well as provide evidence that the type 1 interferon pathway may be an actionable therapeutic target for future studies.

Electrical recognition of the twenty proteinogenic amino acids using an aerolysin nanopore.

Efforts to sequence single protein molecules in nanopores1-5 have been hampered by the lack of techniques with sufficient sensitivity to discern the subtle molecular differences among all twenty amino acids. Here we report ionic current detection of all twenty proteinogenic amino acids in an aerolysin nanopore with the help of a short polycationic carrier. Application of molecular dynamics simulations revealed that the aerolysin nanopore has a built-in single-molecule trap that fully confines a polycationic carrier-bound amino acid inside the sensing region of the aerolysin. This structural feature means that each amino acid spends sufficient time in the pore for sensitive measurement of the excluded volume of the amino acid. We show that distinct current blockades in wild-type aerolysin can be used to identify 13 of the 20 natural amino acids. Furthermore, we show that chemical modifications, instrumentation advances and nanopore engineering offer a route toward identification of the remaining seven amino acids. These findings may pave the way to nanopore protein sequencing.

Multimodal techniques failed to detect cytomegalovirus in human glioblastoma samples.

The role of the human cytomegalovirus (HCMV) in gliomagenesis is largely debated. Contradictory data exist regarding the sensitivity and specificity of HCMV detection techniques, including immunohistochemistry (IHC), in situ hybridization (ISH), and RNA and DNA sequencing. The aim of this study is to detect HCMV in glioblastoma (GBM) tumor samples using IHC, ISH, and real-time PCR (qPCR), as well as to correlate the findings with serological status and HCMV DNA load in blood. Forty-seven patients with histopathological diagnosis of GBM and HCMV serological status were retrospectively reviewed. HCMV DNA quantification in whole blood was performed in 31 patients. The detection of HCMV in tumor samples was performed using IHC in 42 cases, ISH in 10 cases, and qPCR in 29 cases. All but two patients were taking high steroid doses at the time of biological testing. HCMV seroprevalence was 68%. Active infection with HCMV DNA detected in blood was diagnosed in 6 out of 21 (28%) seropositive patients. HCMV was not detected in GBM samples using IHC or ISH, while qPCR was positive in one case (also positive for blood HCMV DNA). These data do not support a crucial role of HCMV in GBM tumorigenesis. HCMV might be reactivated in GBM patients, due to steroid treatment.

Identification of single amino acid differences in uniformly charged homopolymeric peptides with aerolysin nanopore.

There are still unmet needs in finding new technologies for biomedical diagnostic and industrial applications. A technology allowing the analysis of size and sequence of short peptide molecules of only few molecular copies is still challenging. The fast, low-cost and label-free single-molecule nanopore technology could be an alternative for addressing these critical issues. Here, we demonstrate that the wild-type aerolysin nanopore enables the size-discrimination of several short uniformly charged homopeptides, mixed in solution, with a single amino acid resolution. Our system is very sensitive, allowing detecting and characterizing a few dozens of peptide impurities in a high purity commercial peptide sample, while conventional analysis techniques fail to do so.

Imbalanced Angiogenesis in Peripartum Cardiomyopathy　- Diagnostic Value of Placenta Growth Factor.

BACKGROUND: Concentrations of the anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1) are altered in peripartum cardiomyopathy (PPCM). In this study we investigated changes in the angiogenesis balance in PPCM.Methods and Results:Plasma concentrations of sFlt-1 and the pro-angiogenic placenta growth factor (PlGF) were determined in patients with PPCM during the post-partum phase (n=83), in healthy women at delivery (n=30), and in patients with acute heart failure (AHF; n=65). Women with cardiac failure prepartum or associated with any form of hypertension, including pre-eclampsia, were excluded. Compared with non-pregnant women, in women with AHF and PPCM, median PlGF concentrations were greater (19 [IQR 16-22] and 98 [IQR 78-126] ng/mL, respectively; P<0.001) and the sFlt-1/PlGF ratio was lower (9.8 [6.6-11.3] and 1.2 [0.9-2.8], respectively; P<0.001). The sFlt-1/PlGF ratio was lower in PPCM than in normal deliveries (1.2 [0.9-2.8] vs. 94.8 [68.8-194.1], respectively; P<0.0001). The area under the curve for PlGF (cut-off value: 50ng/mL) and/or the sFlt-1/PlGF ratio (cut-off value: 4) to distinguish PPCM from either normal delivery or AHF was >0.94. Median plasma concentrations of the anti-angiogenic factor relaxin-2 were lower in PPCM and AHF (0.3 [IQR 0.3-1.7] and 0.3 [IQR 0.3-1] ng/mL, respectively) compared with normal deliveries (1,807 [IQR 1,101-4,050] ng/mL; P<0.001). CONCLUSIONS: Plasma of PPCM patients shows imbalanced angiogenesis. High PlGF and/or low sFlt-1/PlGF may be used to diagnose PPCM.

Weight Loss, Xanthine Oxidase, and Serum Urate Levels: A Prospective Longitudinal Study of Obese Patients.

OBJECTIVE: The mechanisms by which weight loss decreases serum uric acid (SUA) levels are poorly known. We aimed to investigate the role played by xanthine oxidase (XOD), metabolic status, and low-grade inflammation in decreased SUA levels induced by weight loss in obese patients. METHODS: Data were from a series of consecutive patients with severe obesity involved in a bariatric surgery program. Measurements of body composition and biologic samples were obtained before surgery and 6 months after surgery. RESULTS: Among the 154 patients (mean ± SD age 41.0 ± 12.3 years, body mass index [BMI] 47.8 ± 7.2 kg/m(2) , 81% female), the mean ± SD weight loss at 6 months was 31.3 ± 7.8 kg. Reduction in SUA levels was modest (-10%): 4.98 ± 1.21 mg/dl at 6 months versus 5.52 ± 1.33 mg/dl at baseline (P < 0.001). The decrease in SUA levels was greatest (-18%) in hyperuricemic patients (n = 48). In these patients, circulating XOD activity decreased with weight loss (P < 0.0001). Multiple linear regression analysis revealed decreased SUA levels associated with decreased triglyceride levels (P = 0.0001) and BMI (P = 0.02) but not XOD activity, adipokine levels (leptin and adiponectin), insulin resistance, or levels of inflammatory variables (interleukin 6, orosomucoid, fibrinogen, and high-sensitivity C-reactive protein). CONCLUSION: In obese patients, weight loss was associated with a decrease in both SUA levels and XOD activity. Our findings suggest that reduced SUA levels are not mediated by decreased XOD activity or improved insulin resistance but could be partly due to a reduction in triglyceride levels.

Elevated Plasma B-Type Natriuretic Peptide Concentrations Directly Inhibit Circulating Neprilysin Activity in Heart Failure.

OBJECTIVES: This study sought to hypothesize that elevated B-type natriuretic peptide (BNP) could act as an endogenous neprilysin inhibitor. BACKGROUND: A hallmark of acute decompensated heart failure (ADHF) is the overproduction of natriuretic peptides (NPs) by stretched cardiomyocytes. Various strategies have been developed to potentiate the beneficial effect of the NPs, including the recent use of neprilysin angiotensin receptor inhibitors. Contrary to rodents, human BNP is poorly sensitive to neprilysin degradation while retaining affinity to neprilysin. METHODS: We enrolled 638 patients presenting to the emergency department with acute dyspnea of which 468 had ADHF and 169 had dyspnea of noncardiac origin. We also included 46 patients with stable chronic heart failure (HF) and 10 age-matched healthy subjects. Plasma samples were collected within 4 h after emergency department admission. BNP, neprilysin concentration and activity, and the neprilysin substrate substance P concentration were measured. RESULTS: We found that when plasma BNP rose above 916 pg/ml, neprilysin activity was markedly reduced (p < 0.0001) and stratified 95% of the population into 2 groups: BNP <916 pg/ml/neprilysin activity ≥ 0.21 nmol/ml/min and BNP ≥916 pg/ml/neprilysin activity <0.21 nmol/ml/min with very different prognoses. In vitro, BNP was responsible for neprilysin inhibition. Neprilysin activity was inversely correlated with the concentration of substance P (ρ = -0.80; p < 0.0001). CONCLUSIONS: Besides being an effector of the cardiac response to cardiomyocyte stretching in ADHF, elevated plasma BNP is also an endogenous neprilysin inhibitor. A biologically relevant BNP threshold discriminates 2 populations of HF patients with different vasoactive peptide profiles and outcome. If confirmed, this may identify an important threshold for managing HF patients.

Influence of α-stat and pH-stat blood gas management strategies on cerebral blood flow and oxygenation in patients treated with therapeutic hypothermia after out-of-hospital cardiac arrest: a crossover study.

OBJECTIVES: In patients treated with therapeutic hypothermia after out-of-hospital cardiac arrest, two blood gas management strategies are used regarding the PaCO2 target: α-stat or pH-stat. We aimed to compare the effects of these strategies on cerebral blood flow and oxygenation. DESIGN: Prospective observational single-center crossover study. SETTING: ICU of University hospital. PATIENTS: Twenty-one therapeutic hypothermia-treated patients after out-of-hospital cardiac arrest more than 18 years old without history of cerebrovascular disease were included. INTERVENTIONS: Cerebral perfusion and oxygenation variables were compared in α-stat (PaCO2 measured at 37 °C) versus pH-stat (PaCO2 measured at 32-34 °C), both strategies maintaining physiological PaCO2 values: 4.8-5.6 kPa (36-42 torr). MEASUREMENTS AND MAIN RESULTS: Bilateral transcranial middle cerebral artery flow velocities using Doppler and jugular vein oxygen saturation were measured in both strategies 18 hours (14-23 hr) after the return of spontaneous circulation. Pulsatility and resistance indexes and cerebral oxygen extraction were calculated. Data are expressed as median (interquartile range 25-75) in α-stat versus pH-stat. No differences were found in temperature, arterial blood pressure, and oxygenation between α-stat and pH-stat. Significant differences were found in minute ventilation (p = 0.006), temperature-corrected PaCO2 (4.4 kPa [4.1-4.6 kPa] vs. 5.1 kPa [5.0-5.3 kPa], p = 0.0001), and temperature-uncorrected PaCO2 (p = 0.0001). No differences were found in cerebral blood velocities and pulsatility and resistance indexes in the overall population. Significant differences were found in jugular vein oxygen saturation (83.2% [79.2-87.6%] vs. 86.7% [83.2-88.2%], p = 0.009) and cerebral oxygen extraction (15% [11-20%] vs. 12% [10-16%], p = 0.01), respectively. In survivors, diastolic blood velocities were 25 cm/s (19-30 cm/s) versus 29 cm/s (23-35 cm/s) (p = 0.004), pulsatility index was 1.10 (0.97-1.18) versus 0.94 (0.89-1.05) (p = 0.027), jugular vein oxygen saturation was 79.2 (71.1-81.8) versus 83.3% (76.6-87.8) (p = 0.033), respectively. However, similar results were not found in nonsurvivors. CONCLUSIONS: In therapeutic hypothermia-treated patients after out-of-hospital cardiac arrest at physiological PaCO2, α-stat strategy increases jugular vein blood desaturation and cerebral oxygen extraction compared with pH-stat strategy and decreases cerebral blood flow velocities in survivors.

TMEM127 screening in a large cohort of patients with pheochromocytoma and/or paraganglioma.

CONTEXT: TMEM127 is a novel pheochromocytoma (PCC) susceptibility gene. OBJECTIVES: Our aim was to clearly determine the indications for TMEM127 genetic testing in patients with PCC and/or paraganglioma (PGL). PATIENTS AND METHODS: Germline DNA from 642 unrelated patients who did not carry mutations in major PCC susceptibility genes was analyzed. Five hundred fifty-nine patients were affected by PCC, 72 by PGL (22 with head and neck and 50 with thoracic or abdominal location), and 11 by both PCC and PGL. Analysis of the TMEM127 gene was performed by direct sequencing and quantitative multiplex PCR of short fluorescent fragments. RESULTS: In our cohort six mutations (0.9%) were identified. Three of them (p.Ala47Asp, p.Gln64HisfsX18, p.Tyr164X) were found in patients exhibiting clinical criteria for a hereditary disease (young age at diagnosis, bilateral PCC, or family history). The three others (p.Gln157X, p.Val68SerfsX13, p.Val90Met) were detected in patients with an apparently sporadic presentation. No mutation was found among patients with PGL, and no large chromosomal rearrangement spanning the TMEM127 gene was detected. CONCLUSIONS: Our results combined with the two previous studies suggest that direct sequencing of TMEM127 should be considered, after a negative screening of VHL, RET, SDHB, and SDHD genes, in patients with PCC.

Elucidation of the ATP7B N-domain Mg2+-ATP coordination site and its allosteric regulation.

The diagnostic of orphan genetic disease is often a puzzling task as less attention is paid to the elucidation of the pathophysiology of these rare disorders at the molecular level. We present here a multidisciplinary approach using molecular modeling tools and surface plasmonic resonance to study the function of the ATP7B protein, which is impaired in the Wilson disease. Experimentally validated in silico models allow the elucidation in the Nucleotide binding domain (N-domain) of the Mg(2+)-ATP coordination site and answer to the controversial role of the Mg(2+) ion in the nucleotide binding process. The analysis of protein motions revealed a substantial effect on a long flexible loop branched to the N-domain protein core. We demonstrated the capacity of the loop to disrupt the interaction between Mg(2+)-ATP complex and the N-domain and propose a role for this loop in the allosteric regulation of the nucleotide binding process.

Should kidney tubular markers be adjusted for urine creatinine? The example of urinary cystatin C.

BACKGROUND: Evaluation of specific urinary markers with respect to urine creatinine (uCreat) is common. However, as uCreat is a function of both glomerular filtration and tubular secretion, using uCreat for specific tubular markers, suggests that glomerular function is normal, and there is no tubular secretion. Thus, adjusting values of any tubular marker to uCreat, especially in patients with acute or even moderate chronic renal failure, can be misleading. METHODS: Using urine cystatin-C (uCST3) as a model tubular marker for following 120 kidney graft recipients daily, we evaluated the utility of either uCST3 alone or the uCST3/uCreat ratio to detect tubular damage. All positive kidney biopsies were always associated with a uCST3>0.18 mg/L. RESULTS: Using the uCST3/uCreat ratio, discrepancies regarding biopsy status were observed in nine patients (4 false positive, 5 false negative results). In two patients, variability of uCreat appeared to be the most important factor causing inconsistent uCST3/uCreat ratios. With a negative predictive value (NPV) of 85.7%, uCST3/uCreat can lead to errors in clinical interpretation. These errors can be avoided when estimates of tubular damage are based on uCST3 concentrations alone (NPV=100%). CONCLUSIONS: We recommend using the uCST3 value to evaluate the extent of renal tubular damage. Indeed, our conflicting results on uCST3/uCreat can be extended to every marker of tubular function. Evaluating a urine marker specific for renal tubular damage to a second urine marker that is itself strongly dependent upon glomerular or other renal or non-renal conditions, impairs its clinical relevance and may lead to incorrect interpretations. Correction with uCreat can be performed only in pure glomerulopathy, when specific markers of glomerular function are measured (i.e., urinary albumin). In all other cases of renal diseases, such correction is inappropriate and should be avoided. Clin Chem Lab Med 2009;47:1553-6.

Cellular prion protein coupling to TACE-dependent TNF-alpha shedding controls neurotransmitter catabolism in neuronal cells.

Despite considerable efforts to unravel the role of cellular prion protein (PrP(C)) in neuronal functions, the mechanisms by which PrP(C) takes part in the homeostasis of a defined neuronal phenotype remain poorly characterized. By taking advantage of a neuroectodermal cell line (1C11) endowed with the capacity to differentiate into serotonergic (1C11(5-HT)) or noradrenergic (1C11(NE)) neurons, we assessed the contribution of PrP(C) to bioaminergic cell functions. We established that in 1C11-derived neuronal cells antibody-mediated PrP(C) ligation triggered tumor necrosis factor (TNF)-alpha release, through recruitment of the metalloproteinase TNF-alpha converting enzyme (TACE). TNF-alpha shed in response to PrP(C) acts as a second message signal, eliciting serotonin (5-HT) or norepinephrine (NE) degradation in 1C11(5-HT) or 1C11(NE) cells, respectively. Our data thus introduced TNF-alpha as a PrP(C)-dependent modulator of neuronal metabolism. Of note, we previously reported on a control of neurotransmitter catabolism by 5-HT(2B) or alpha(1D) autoreceptors in 1C11 bioaminergic neurons, via the same TACE/TNF-alpha pathway (Ann. N Y Acad. Sci. 1091, 123). Here, we show that combined stimulation of PrP(C) and these two bioaminergic receptors add their effects on neurotransmitter degradation. Overall, these observations unveil a novel contribution of PrP(C) to the control of neuronal functions and may have implications regarding dysfunction of the bioaminergic systems in prion diseases.