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Background:People with rheumatoid arthritis (RA) have a higher risk of serious infections. The most common nosocomial infection in the United States (US) is Clostridioides difficile infection (CDI) and yet, little is known regarding the impact of comorbid RA on outcomes in persons hospitalized with CDI.Objectives:To evaluate the trends over time and predictors of inpatient mortality in hospitalized patients with CDI comparing those with and without RA.Methods:We used the National Inpatient Sample (NIS) database, the largest available all-payer database of inpatient hospitalizations in the US. Patients aged ≥18 years admitted with CDI from 2006-2018 were included. Patients with RA were identified using the International Classification of Diseases (ICD) 9 and 10 codes. Categorical variables between CDI patients with and without RA were compared using Chi-squared test. Temporal trends of hospitalization charges, length of stay (LOS) and inpatient mortality were assessed using the Cochrane Armitage test. Predictors of inpatient mortality were assessed using multivariable logistic regression adjusting for: age ≥65, sex, race, presence of RA, and Elixhauser comorbidity index.Results:There were 4,396,945 hospitalizations with a discharge diagnosis of CDI in the study period, of which 111,336 (2.5%) had a coexisting diagnosis of RA. Over the study period, the proportion of CDI patients with a diagnosis of RA increased from 1.7% in 2006 to 3.3% in 2018 with a statistically significant trend of rise (p trendp The inflation-adjusted average charge for hospitalization for CDI without RA was significantly higher than for CDI with RA ($95,863 vs $73,025, pCDI patients without RA had a significantly higher mortality over the study period than those with RA (7.8% vs 6.1%, pThe multivariable analyses found age≥65 was associated with increased inpatient mortality (adjusted odds ratio [aOR], 1.77, 95% confidence interval [CI], 1.73-1.80), whereas a diagnosis of RA was associated with a decreased mortality (aOR 0.86, 95% CI, 0.81-0.91) (Table 1).Table 1.Predictors of inpatient mortalityaOR95% C.I. for aORP-valueLowerUpperAge ≥ 651.7651.7301.801Hospitalization years -Years 2006-2011Ref -Years 2011-20140.7070.6930.721 -Years 2015-20180.5820.5690.594Elixhauser Comorbidity Index1.0561.0551.056Rheumatoid Arthritis0.8590.8100.911Female0.8700.8550.885Race -WhiteRef -African American1.0711.0441.099 -Hispanic1.1441.1081.180 -Asian/Pacific Islander1.2671.2001.337 -Native American1.0220.9101.1470.716 -Other races1.2631.2011.329aOR = Adjusted Odds Ratio; C.I.= confidence intervalConclusion:In this nationwide study, among hospitalized patients with CDI, those with comorbid RA had significantly decreased odds of inpatient mortality than those without RA. Further studies are needed to understand this association.Figure 1.Disclosure of Interests:None declared

Introduction Veno-venous extracorporeal membrane oxygenation (VV-ECMO) as bridge to recovery in critically ill COVID-19 continues to be commonly utilized strategy in cases with persistent respiratory failure refractory to traditional ventilation support Case Report We report 5 cases of severe acute respiratory syndrome coronavirus-2 infection (SARS-CoV-2) who were treated with ECMO (Table 1). All 5 cases presented with fever, cough and shortness of breath and a positive nasopharyngeal swab for SARS-CoV-2 on admission. Case 1, 2, 3 and 5 patients were hypoxemic with saturation less than 90% on admission and decompensated rapidly, whereas Case 4 decompensated after day 14. Mechanical ventilation failed to provide adequate oxygenation in all 5 cases; case 2,3 and 5 were started on recruitment measures with proning while it was not possible for case 1 owing to morbid obesity. Proning was not possible in the case 4 as patient became severely hypoxemic while patient was undergoing mechanical thrombectomy. The case 1-4 remained on ECMO for 19, 17, 17 and 2 days respectively. All except case 2 had improvement in APACHEII and SOFA score after ECMO initiation. All 5 patients had elevated inflammatory markers of serum ferritin, D-dimer, Lactate dehydrogenase (LDH), C-reactive protein (CRP) which trended down after a few days of ECMO initiation All 5 patients received high dose steroids during their stay in the ICU. Case 4 and 5 passed away after compassionate extubation. Case 1-3 had prolonged hospital course with complication of hospital acquired pneumonia requiring multiple courses of broad-spectrum antibiotics. Summary Our observational report of 5 patients reports the use of ECMO in critically ill SARS-CoV-2 with ARDS and difficult to maintain saturation despite mechanical ventilation and proning with recovery for 3 patients. However, given the lack of ECMO centers; this is not a readily available option. Further studies are warranted to investigate the role of ECMO in SARRS-CoV-2 and careful identification of appropriate candidates.

The present study analyzes by RT-qPCR the expression of microRNA (miRNA)-27a-3p, miRNA-124-3p, miRNA-132-3p, and miRNA-143-3p in the locus coeruleus (LC), entorhinal cortex (EC), CA1 region of the hippocampus (CA1), and dentate gyrus (DG) of middle-aged (MA) individuals with no brain lesions and of cases at Braak and Braak stages I-II and II-IV of neurofibrillary tangle (NFT) pathology. The most affected region is the LC in which miRNA-27a-3p, miRNA-124-3p, and miRNA-143-3p show a trend to increase at stages I-II and are significantly up-regulated at stages III-IV when compared with MA. Only miRNA-143-3p is up-regulated in the EC at stages III-IV when compared with MA and with stages I-II. No modifications in the expression levels of miRNA-27a-3p, miRNA-124-3p, miRNA-132-3p, and miRNA-143-3p are found in CA1 at any stage, whereas miRNA-124-3p is significantly down-regulated in DG at stages I-II. Accompanying in situ hybridization reveals miRNA-27a-3p, miRNA-124-3p, and miRNA-143-3 localization in neurons, indicating that changes in miRNA expression are not a direct effect of changes in the numbers of neurons and glial cells. Present observations show for the first time important miRNA de-regulation in the LC at the first stages of NFT. Since the LC is the main noradrenergic input to the cerebral cortex, key regulator of mood and depression, and one of the first nuclei affected in aging and Alzheimer's disease (AD), these findings provide insights for additional study of the LC in aging and AD.

Traditionally ST-elevation myocardial infarction (STEMI) with multivessel coronary artery disease is treated with percutaneous coronary intervention (PCI) to culprit lesion only. The benefit of multivessel (MV) PCI among STEMI patients without cardiogenic shock is unclear.PubMed, EMBASE, and Cochrane Database were searched from 1996 to 2019, for studies of patients with STEMI without cardiogenic shock, who underwent PCI. Only randomized controlled trials comparing culprit PCI to MV PCI vs culprit vessel PCI were included for pairwise meta-analysis. All-cause mortality, cardiac mortality, reinfarction, revascularization and major adverse cardiovascular events (MACE) were compared. Trial sequential analysis (TSA) was performed for outcome variables.Nine randomized controlled trials contributed 6930 patients meeting inclusion criteria. Three thousand three hundred seventy-six underwent MV PCI, and 3554 underwent culprit PCI. Our analysis demonstrated no significant difference in all-cause mortality. MV PCI had a lower risk of cardiac mortality, reinfarction, MACE and repeat revascularization compared to culprit PCI (P values0.05). TSA showed futility for further trials to detect all-cause mortality benefit and lack of firm evidence of benefit in cardiac mortality and re-infarction, but firm evidence of benefit in revascularization and MACE.In conclusion, MV PCI strategy was beneficial in reducing cardiac mortality, reinfarction, repeat revascularization, and MACE but there was no all-cause mortality benefit when compared to culprit only PCI strategy. Evidence for benefit in cardiac mortality and re-infarction is not robust per TSA.

Introduction We present a case of COVID-19 causing hypercoagulability and inflammatory stress leading to STEMI in a patient who went on to develop persistent cardiogenic shock requiring LVA) implantation. Case Report 57-year-old lady developed COVID-19 infection in May 2020. In June 2020, she presented with chest pain, was noted to have STEMI on EKG, complicated by cardiac arrest with ROSC in 14 minutes. She was in cardiogenic shock as well and was started on veno-arterial ECMO. She underwent left anterior descending artery stent placement. Further hospitalization was complicated by persistent cardiogenic shock and complete heart block and underwent pacemaker and cardiac-defibrillator implantation. She developed pulmonary edema, acute kidney injury requiring hemodialysis, shock liver, and persistent cardiogenic shock. She was weaned off VA-ECMO after 4 days but continued to have severely reduced cardiac function. RHC revealed severe volume overload, pulmonary venous hypertension, low cardiac output, and right heart dysfunction. Echo showed severe LV dysfunction with an EF of 15%. A femoral intra-aortic balloon pump(IABP) was placed on July 7, 2020. An attempt was made to wean her off of IABP on July 10th,however, it was unsuccessful and she was transitioned to axillary intra-aortic balloon pump. She remained IABP dependent thereafter and on July 15th, given persistent cardiogenic shock, decision was made to pursue advanced heart failure therapies. After multi-disciplinary discussion, the decision to pursue LVAD implantation was made. She underwent a successful LVAD implantation on July 20th . She failed an extubation trial and underwent tracheostomy on July 23rd . Post LVAD, she developed atrial fibrillation and was started on digoxin and amiodarone. Her symptoms improved and she was subsequently discharged to rehabilitation in late August on amiodarone, digoxin, metoprolol, prasugrel, warfarin, spironolactone and lisinopril. The detailed timeline is shown in figure 1. Summary Hypercoagulability and severe inflammatory stress leading to life-threatening illness is a significant complication of COVID-19 infection. A low threshold for suspecting and treating hypercoagulability and inflammatory induced myocardial ischemia and injury and cardiogenic shock is a reasonable strategy to decrease acute as well as chronic morbidity and mortality.

Introduction Heart failure patients with difficult to manage volume status and recurrent heart failure exacerbation benefit from CardioMemsTM placement. This helps in remote monitoring of pulmonary artery (PA) pressure and diuretic dosing can be changed on the basis of these readings preventing hospitalizations. During the COVID-19 pandemic, a stay-at-home order was issued by the state government, which may have led to heart failure deterioration secondary to poor follow up and change in dietary habits. Hypothesis We aim to evaluate changes in the mean PA pressure during stay-at-home order during COVID-19 pandemic as patients are not seen in clinic and there are presumed changes in dietary habits. Methods We identified 26 patients with a history of CardioMemsTM implant using our heart failure clinic database. We extracted their daily available PA pressure reading before the COVID-19 pandemic and during pandemic. Results The characteristics of the patients are described in Table 1. 26 cases with were identified with sufficient CardioMemsTM readings. Average age was 69.7 years with 38.5% females. There were 54% patients with systolic heart failure. Number of COVID-19 cases rose to almost 700 in 1 month. With regression analysis, we observed a trend towards increase in the mean PA pressure readings during the pandemic (R2 = 0.09, P-value

Streptobacillus moniliformis is a pleomorphic bacillus found in the oral cavity of rodents. Rat bite can transmit these bacteria to humans and can lead to bacteremia as well as infective endocarditis. We present an unusual case rat-bite endocarditis and septic emboli. 24 year-old-female presented

Transcatheter aortic valve replacement (TAVR) is an evolving treatment for symptomatic aortic stenosis (AS). We present a case of aorta to right ventricle (RV) fistula as a rare complication of TAVR. 90-year-old male with history of systolic heart failure and severe AS presented to hospital with

Amlodipine toxicity is commonly reported medication involved in overdose. Its management involves early action with aggressive measures. We describe such a case managed successfully. 64-year-old female was admitted to hospital with severe hypotension and junctional rhythm 36 hours following

Hydralazine-induced lupus syndrome (HILS) is an uncommon drug reaction that typically manifests as fever, myalgia, serositis, and arthralgia. This is a rare presentation of HILS with pericardial effusion. A 57-year-old male with hypertension and chronic kidney disease presented with a four-week

International audience; Cerebellar damage and granular and Purkinje cell loss in sporadic Creutzfeldt-Jakob disease (sCJD) highlight a critical involvement of the cerebellum during symptomatic progression of the disease. In this project, global proteomic alterations in the cerebellum of brain from the two most prevalent subtypes (MM1 and VV2) of sCJD were studied. Two-dimensional gel electrophoresis (2DE) coupled mass spectrometric identification revealed 40 proteins in MM1 and 43 proteins in VV2 subtype to be differentially expressed. Of those, 12 proteins showed common differential expression in their expression between two subtypes. Differentially expressed proteins mainly belonged to (i) cell cycle, gene expression and cell death; (ii) cellular stress response/oxidative stress (OS) and (iii) signal transduction and synaptic functions, related molecular functions. We verified 10 differentially expressed proteins at transcriptional and translational level as well. Interestingly, protein deglycase DJ-1 (an antioxidative protein) showed an increase in its messenger RNA (mRNA) expression in both MM1 and VV2 subtypes but protein expression only in VV2 subtype in cerebellum of sCJD patients. Nuclear translocalization of DJ-1 confirmed its expressional alteration due to OS in sCJD. Downstream experiments showed the activation of nuclear factor erythroid-2 related factor 2 (Nrf2)/antioxidative response element (ARE) pathway. DJ-1 protein concentration was significantly increased during the clinical phase in cerebrospinal fluid of sCJD patients and also at presymptomatic and symptomatic stages in cerebellum of humanized PrP transgenic mice inoculated with sCJD (MM1 and VV2) brain. These results suggest the implication of oxidative stress during the pathophysiology of sCJD.

International audience; A high priority in the prion field is to identify pre-symptomatic events and associated profile of molecular changes. In this study, we demonstrate the pre-symptomatic dysregulation of cytoskeleton assembly and its associated cofilin-1 pathway in strain and brain region-specific manners in MM1 and VV2 subtype-specific Creutzfeldt-Jakob disease at clinical and pre-clinical stage. At physiological level, PrPC interaction with cofilin-1 and phosphorylated form of cofilin (p-cofilin(Ser3)) was investigated in primary cultures of mouse cortex neurons (PCNs) of PrPC wild-type and knockout mice (PrP-/-). Short-interfering RNA downregulation of active form of cofilin-1 resulted in the redistribution/downregulation of PrPC, increase of activated form of microglia, accumulation of dense form of F-actin, and upregulation of p-cofilin(Ser3). This upregulated p-cofilin(Ser3) showed redistribution of expression predominantly in the activated form of microglia in PCNs. At pathological level, cofilin-1 expression was significantly altered in cortex and cerebellum in both humans and mice at pre-clinical stage and at early symptomatic clinical stage of the disease. Further, to better understand the possible mechanism of dysregulation of cofilin-1, we also demonstrated alterations in upstream regulators; LIM kinase isoform 1 (LIMK1), slingshot phosphatase isoform 1 (SSH1), RhoA-associated kinase (Rock2), and amyloid precursor protein (APP) in sporadic Creutzfeldt-Jakob disease MM1 mice and in human MM1 and VV2 frontal cortex and cerebellum samples. In conclusion, our findings demonstrated for the first time a key pre-clinical response of cofilin-1 and the associated pathway in prion disease.

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most prevalent form of human prion disease and it is characterized by the presence of neuronal loss, spongiform degeneration, chronic inflammation and the accumulation of misfolded and pathogenic prion protein (PrPSc). The molecular mechanisms underlying these alterations are largely unknown, but the presence of intracellular neuronal calcium (Ca2+) overload, a general feature in models of prion diseases, is suggested to play a key role in prion pathogenesis. Here we describe the presence of massive regulation of Ca2+ responsive genes in sCJD brain tissue, accompanied by two Ca2+-dependent processes: endoplasmic reticulum stress and the activation of the cysteine proteases Calpains 1/2. Pathogenic Calpain proteins activation in sCJD is linked to the cleavage of their cellular substrates, impaired autophagy and lysosomal damage, which is partially reversed by Calpain inhibition in a cellular prion model. Additionally, Calpain 1 treatment enhances seeding activity of PrPSc in a prion conversion assay. Neuronal lysosomal impairment caused by Calpain over activation leads to the release of the lysosomal protease Cathepsin S that in sCJD mainly localises in axons, although massive Cathepsin S overexpression is detected in microglial cells. Alterations in Ca2+ homeostasis and activation of Calpain-Cathepsin axis already occur at pre-clinical stages of the disease as detected in a humanized sCJD mouse model. Altogether our work indicates that unbalanced Calpain-Cathepsin activation is a relevant contributor to the pathogenesis of sCJD at multiple molecular levels and a potential target for therapeutic intervention. Electronic supplementary material The online version of this article (doi:10.1186/s40478-017-0431-y) contains supplementary material, which is available to authorized users.

List of Taqman assays used in this study. (PPTX 53 kb)

Increased rPrP aggregation induced by sCJD brain homogenates. Recombinant prion protein was incubated with brain homogenates from control and sCJD brains (n = 4) and subjected to Western-blot with PrP SAF70 antibody. (PPTX 195 kb)

Calpain substrates levels in sCJD. (A) qPCR analysis of CAPNS1/CAPN4 in the frontal cortex and cerebellum of controls and sCJD MM and VV2 cases. (B) Western-blot and densitometry analysis of Neurofilament Light (NF-L) and γ-Tubulin in the frontal cortex and cerebellum of control, sCJD MM1 and sCJD VV2 cases. ANOVA test followed by post-test Tukey’s Multiple Comparison Test was used to compare the values from different groups. P values for the comparisons of the three groups are indicated in the figure:*p

There is an increasing demand for the understanding of pathophysiology on neurodegeneration diseases at early stages. Changes in endocytic machinery and the cytoskeleton-associated response are the first alterations observed in Creutzfeldt-Jakob disease (CJD) and Alzheimer's disease AD brain. In this study, we performed a targeted search for endocytic pathway proteins in the different regions of the brain. We found late endosome marker Rab7a which was significantly upregulated in the frontal cortex region in the rapid progressive CJD form (MM1) and rapid progressive AD (rpAD) forms. However, Rab9 expression was significantly downregulated only in CJD-MM1 brain frontal cortex region. In the cerebellum, Rab7a expression showed significant upregulation in both subtype MM1 and VV2 CJD forms, in contrast to Rab9 which showed significant downregulation in both subtype MM1 and VV2 CJD forms at terminal stage of the disease. To check regulatory response at pre-symptomatic stage of the disease, we checked the regulatory interactive response of Rab7a, Rab9, and known biomarkers PrP(C) and tau forms in frontal cortex at pre-symptomatic stage of the disease in tg340 mice expressing about fourfold of human PrP-M129 with PrP-null background that had been inoculated with human sCJD MM1 brain tissue homogenates (sCJD MM1 mice). In addition, we analyzed 5XFAD mice, exhibiting five mutations in the APP and presenilin genes related to familial Alzheimer's disease (FAD), to validate specific regulatory response of Rab7a, Rab9, tau, and phosphorylated form of tau by immunostaining 5XFAD mice in comparison with the wild-type age-matched mice brain. The cortical region of 5XFAD mice brain showed accumulated form of Rab7a in puncta that co-label for p-Tau, indicating colocalization by using confocal laser-scanning microscopy and was confirmed by using reverse co-immunoprecipitation. Furthermore, synthetic RNA (siRNA) against the Rab7a gene decreased expression of Rab7a protein, in cortical primary neuronal cultures of PrP(C) wild type. This depleted expression of Rab7a led to the increased accumulation of PrP(C) in Rab9-positive endosomal compartments and consequently an increased co-localization between PrP(C)/Rab9; however, total tau level decreased. Interestingly, siRNA against tau gene in cortical primary neuronal cultures of PrP(C) wild-type mice showed enhanced Rab7a and Rab9 expression and increase formation of dendritic spines. The work described highlighted the selective involvement of late endosomal compartment marker Rab7a in CJD, slow and rapid progressive forms of AD pathogenesis.

Inhibition of RT-QuIC reaction by Doxycycline. RT-QuIC assay performed in the presence of sCJD brain homogenates (n = 3) as seeding material, previously treated with recombinant Calpain in the presence (+DOX) of absence (−DOX) of Doxycycline (DOX). Relative Fluorescence Units (RFU) are shown. (PPTX 47 kb)

ER stress in the frontal cortex of sCJD cases. ER stress and Ca2+ induced genes in sCJD MM1 by (A) Western-blot (grp78, hsp27, BDNF, Fas and Bcl-2) and (B) Bcl-2/Bax ratio in the frontal cortex of control and sCJD MM1 cases obtained from the densitometric analysis of both proteins detected by western-blot analysis. Unpaired t-test (95% CI) was used for the comparisons of the two groups. *p

Alteration of autophagy related genes in sCJD. (A) Altered expression of genes involved in autophagy in the cortex of the tg340-PRNP129MM mice at 120 (pre-clinical) and 180 (clinical) days after inoculation with sCJD MM1 brain homogenates. (B) qPCR analysis of the autophagy activators hspa8 and hspb8 in the sCJD infected tg340-PRNP129MM mice at 180 dpi. (C) Western.-blot and densitometric analysis of the autophagy related proteins DJ-1, LC3, ATG5 and LAMP2 in the frontal cortex of control and sCJD MM1 and sCJD VV2 cases. (D) qPCR analysis of the autophagy-related genes HSPA8, HSPB8, PARK (DJ-1) and LAMP2 in the frontal cortex of control and sCJD MM1 and sCJDVV2 cases. Unpaired t-test (95% CI) was used for the comparisons of the two groups. ANOVA test followed by post-test Tukey’s Multiple Comparison Test was used to compare the values from different groups. P values for the comparisons of the three groups are indicated in the figure:*p

Cathepsin S and GAPDH levels in lysosomal and cytoplasmic enriched fractions derived from prion protein peptide treatment. (PPTX 88 kb)

Partial UPR activation in the frontal cortex of sCJD cases. (A) Western-blot and densitometric analysis of UPR proteins CHOP, ATF4, P-IRE-1, IRE-1, XBP1 and ATF6 in the frontal cortex of control and sCJD MM1 cases. (B) Immunohistochemical detection of CHOP in the frontal cortex of control and sCJD MM1 cases. (B) Immunohistochemical detection of CHOP in the cortex of control and sCJD MM1 inoculated tg340-PRNP129MM mice. Brain slices were counterstained with DAPI. (PPTX 4 kb)

The correlation between masses identified on implantable cardiac devices and device related infective endocarditis (DRE) is not well established. This was a retrospective analysis including patients with prior implantable cardiac devices who underwent trans-esophageal echocardiograms (TEE) from

Fatal familial insomnia is a rare disease caused by a D178N mutation in combination with methionine (Met) at codon 129 in the mutated allele of PRNP (D178N-129M haplotype). FFI is manifested by sleep disturbances with insomnia, autonomic disorders and spontaneous and evoked myoclonus, among other symptoms. This study describes new neuropathological and biochemical observations in a series of eight patients with FFI. The mediodorsal and anterior nuclei of the thalamus have severe neuronal loss and marked astrocytic gliosis in every case, whereas the entorhinal cortex is variably affected. Spongiform degeneration only occurs in the entorhinal cortex. Synaptic and fine granular proteinase K digestion (PrPres) immunoreactivity is found in the entorhinal cortex but not in the thalamus. Interleukin 6, interleukin 10 receptor alpha subunit, colony stimulating factor 3 receptor and toll-like receptor 7 mRNA expression increases in the thalamus in FFI. PrPc levels are significantly decreased in the thalamus, entorhinal cortex and cerebellum in FFI. This is accompanied by a particular PrPc and PrPres band profile. Altered PrP solubility consistent with significantly reduced PrP levels in the cytoplasmic fraction and increased PrP levels in the insoluble fraction are identified in FFI cases. Amyloid-like deposits are only seen in the entorhinal cortex. The RT-QuIC assay reveals that all the FFI samples of the entorhinal cortex are positive, whereas the thalamus is positive only in three cases and the cerebellum in two cases. The present findings unveil particular neuropathological and neuroinflammatory profiles in FFI and novel characteristics of natural prion protein in FFI, altered PrPres and Scrapie PrP (abnormal and pathogenic PrP) patterns and region-dependent putative capacity of PrP seeding.

International audience; Small GTPases of the Arf family mainly activate the formation of coated carrier vesicles. We showed that classI Arf1 interacts specifically with full length GPI-anchored cellular prion protein (PrPC). Several recent reports have also demonstrated a missing link between the endoplasmic reticulum and the Golgi-complex role for proper folding, but the exact molecular mechanism is not yet fully understood. In the present study, we identified and characterized the interactive role of Arf1 during PrPC intracellular distribution under pathophysiological conditions. PrPC interaction with Arf1 was investigated in cortical primary neuronal cultures of PrPC wild type and knockout mice (PrP-/-). Arf1 and PrPC co-binding affinity was confirmed using reverse co-immunoprecipitation, co-localization affinity using confocal laser-scanning microscopy. Treatment with brefeldin-A modulated Arf1 expression and resulted in down-regulation and redistribution of PrPC into cytosolic region. In the pre-symptomatic stage of the disease, Arf1 expression was significantly downregulated in the frontal cortex in tg340 mice expressing about fourfold of human PrP-M129 with PrP null background that had been inoculated with human sCJD MM1 brain tissue homogenates (sCJD MM1 mice). In addition, the frontal cortex of CJD human brain demonstrated significant binding capacity of Arf1 protein using co-immunoprecipitation analysis. We also examined Arf1 expression in the brain of CJD patients with the subtypesMM1 and VV2 and found that it was regulated in a region-specific manner. In the frontal cortex, Arf1 expression was not significantly changed in either MM1 or VV2 subtype. Interestingly, Arf1 expression was significantly reduced in the cerebellum in both subtypes as compared to controls. Furthermore, we observed altered RhoA activity, which in turn affects myosin light-chain (MLC) phosphorylation and Arf1-dependent PI3K pathway. Together, our findings underscore a key early symptomatic role of Arf1 in neurodegeneration. Targeting the Arf/Rho/MLC signaling axis might be a promising strategy to uncover the missing link which probably influences disease progression and internal homeostasis of misfolded proteins.

The cellular prion protein (PrPC) is a glycoprotein, anchored to the plasma membrane and abundantly expressed in the central nervous system. The expression of PrPC in the peripheral tissues is low and only little information is available on its functions in the nonneuronal tissues. The antioxidant function of PrPC during the activation of hepatic stellate cells has already been reported. Therefore, the aim of the study was to expand our knowledge on the functions of PrPC by detailed characterization of its expressional profile in the liver. In a combined strategy by using capillary immunoelectrophoresis and standard techniques, we have shown a sexually dimorphic expression of PrPC in mice and human liver tissues. Further, we showed a significant age-dependent upregulation of PrPC expression in the liver of 14- and 9-month-old mice as compared to 3 months of age. Therefore, this study may provide new insights into the gender-specific role of PrPC in the liver, which may further be linked to its protective role against oxidative stress during aging. In addition, the current study also shows an application of immunoelectrophoresis with a low coefficient of variation to analyze the miniscule amount of PrPC in the mouse liver tissue.

Accumulation of conformationally altered cellular proteins (i.e., prion protein) is the common feature of prions and other neurodegenerative diseases. Previous studies demonstrated that the lack of terminal sequence of cellular prion protein (PrPC), necessary for the addition of glycosylphosphatidylinositol lipid anchor, leads to a protease-resistant conformation that resembles scrapie-associated isoform of prion protein. Moreover, mice overexpressing the truncated form of PrPC showed late-onset, amyloid deposition, and the presence of a short protease-resistant PrP fragment in the brain similar to those found in Gerstmann–Straussler–Scheinker disease patients. Therefore, the physiopathological function of truncated_/anchorless 23–230 PrPC (Δ23–230 PrPC) has come into focus of attention. The present study aims at revealing the physiopathological function of the anchorless PrPC form by identifying its interacting proteins. The truncated_/anchorless Δ23–230 PrPC along with its interacting proteins was affinity purified using STrEP-Tactin chromatography, in-gel digested, and identified by quadrupole time-of-flight tandem mass spectrometry analysis in prion protein-deficient murine hippocampus (HpL3-4) neuronal cell line. Twenty-three proteins appeared to interact with anchorless Δ23–230 PrPC in HpL3-4 cells. Out of the 23 proteins, one novel protein, pyruvate kinase isozymes M1/M2 (PKM2), exhibited a potential interaction with the anchorless Δ23–230 form of PrPC. Both reverse co-immunoprecipitation and confocal laser-scanning microscopic analysis confirmed an interaction of PKM2 with the anchorless Δ23–230 form of PrPC. Furthermore, we provide the first evidence for co-localization of PKM2 and PrPC as well as PrPC-dependent PKM2 expression regulation. In addition, given the involvement of PrPC in the regulation of apoptosis, we exposed HpL3-4 cells to staurosporine (STS)-mediated apoptotic stress. In response to STS-mediated apoptotic stress, HpL3-4 cells transiently expressing 23–230-truncated PrPC were markedly less viable, were more prone to apoptosis and exhibited significantly higher PKM2 expressional regulation as compared with HpL3-4 cells transiently expressing full-length PrPC (1–253 PrPC). The enhanced STS-induced apoptosis was shown by increased caspase-3 cleavage. Together, our data suggest that the misbalance or over expression of anchorless Δ23–230 form of PrPC in association with the expressional regulation of interacting proteins could render cells more prone to cellular insults-stress response, formation of aggregates and may ultimately be linked to the cell death.

Additional file 1. Supplementary Information.