BBA - Molecular Basis of Disease (v.1862, #10)
Editorial Board (i).
Transcriptional profiling of CD11c-positive microglia accumulating around amyloid plaques in a mouse model for Alzheimer's disease by Willem Kamphuis; Lieneke Kooijman; Sjoerd Schetters; Marie Orre; Elly M. Hol (1847-1860).
Amyloid plaques in Alzheimer's disease (AD) mice are surrounded by activated microglia. The functional role of microglia activation in AD is not well understood; both detrimental and beneficial effects on AD progression have been reported. Here we show that the population of activated microglia in the cortex of the APPswe/PS1dE9 mouse AD model is divided into a CD11c-positive and a CD11c-negative subpopulation.Cd11c transcript levels and number of CD11c-positive microglia increase sharply when plaques start to occur and both parameters continue to rise in parallel with the age-related increasing plaque load. CD11c cells are localized near plaques at all stages of the disease development and constitute 23% of all activated microglia. No differences between these two populations were found in terms of proliferation, immunostaining intensity of Iba1, MHC class II, CD45, or immunoproteasome subunit LMP7/β5i. Comparison of the transcriptome of isolated CD11c-positive and CD11c-negative microglia from the cortex of aged APPswe/PS1dE9 with WT microglia showed that gene expression changes had a similar general pattern. However, a differential expression was found for genes involved in immune signaling (Il6, S100a8/Mrp8, S100a9/Mrp14, Spp1, Igf1), lysosome activation, and carbohydrate- and cholesterol/lipid-metabolism (Apoe). In addition, the increased expression of Gpnmb/DC-HIL, Tm7sf4/DC-STAMP, and Gp49a/Lilrb4, suggests a suppressive/tolerizing influence of CD11c cells.We show that amyloid plaques in the APP/PS1 model are associated with two distinct populations of activated microglia: CD11c-positive and CD11c-negative cells. Our findings imply that CD11c-positive microglia can potentially counteract amyloid deposition via increased Aβ-uptake and degradation, and by containing the inflammatory response.
Keywords: Microglia; Aβ; Gene expression; Inflammation; CD11C; CD11b;
CYP4F2 affects phenotypic outcome in adrenoleukodystrophy by modulating the clearance of very long-chain fatty acids by Catherine E. van Engen; Rob Ofman; Inge M.E. Dijkstra; Tessa Jacobs van Goethem; Eveline Verheij; Jennifer Varin; Michel Vidaud; Ronald J.A. Wanders; Patrick Aubourg; Stephan Kemp; Mathieu Barbier (1861-1870).
X-linked adrenoleukodystrophy (ALD) is a severe neurodegenerative disorder caused by the accumulation of very long-chain fatty acids (VLCFA) due to mutations in the ABCD1 gene. The phenotypic spectrum ranges from a fatal cerebral demyelinating disease in childhood (cerebral ALD) to a progressive myelopathy without cerebral involvement in adulthood (adrenomyeloneuropathy). Because ABCD1 mutations have no predictive value with respect to clinical outcome a role for modifier genes was postulated. We report that the CYP4F2 polymorphism rs2108622 increases the risk of developing cerebral ALD in Caucasian patients. The rs2108622 polymorphism (c.1297G > A) results in an amino acid substitution valine for methionine at position 433 (p.V433M). Using cellular models of VLCFA accumulation, we show that p.V433M decreases the conversion of VLCFA into very long-chain dicarboxylic acids by ω-oxidation, a potential escape route for the deficient peroxisomal β-oxidation of VLCFA in ALD. Although p.V433M does not affect the catalytic activity of CYP4F2 it reduces CYP4F2 protein levels markedly. These findings open perspectives for therapeutic interventions in a disease with currently limited treatment options.Display Omitted
Keywords: Adrenoleukodystrophy; Modifier gene; Dicarboxylic acids; Cytochrome P450; Omega-oxidation; Peroxisomes;
Aberrant protein phosphorylation in Alzheimer disease brain disturbs pro-survival and cell death pathways by M. Perluigi; E. Barone; F. Di Domenico; D.A. Butterfield (1871-1882).
Protein phosphorylation of serine, threonine, and tyrosine residues is one of the most prevalent post-translational modifications fundamental in mediating diverse cellular functions in living cells. Aberrant protein phosphorylation is currently recognized as a critical step in the pathogenesis and progression of Alzheimer disease (AD). Changes in the pattern of protein phosphorylation of different brain regions are suggested to promote AD transition from a presymptomatic to a symptomatic state in response to accumulating amyloid β-peptide (Aβ).Several experimental approaches have been utilized to profile alteration of protein phosphorylation in the brain, including proteomics. Among central pathways regulated by kinases/phosphatases those involved in the activation/inhibition of both pro survival and cell death pathways play a central role in AD pathology.We discuss in detail how aberrant phosphorylation could contribute to dysregulate p53 activity and insulin-mediated signaling. Taken together these results highlight that targeted therapeutic intervention, which can restore phosphorylation homeostasis, either acting on kinases and phosphatases, conceivably may prove to be beneficial to prevent or slow the development and progression of AD.
Keywords: Protein phosphorylation; Alzheimer disease; p53; Insulin; Proteomics;
Baicalein inhibits α-synuclein oligomer formation and prevents progression of α-synuclein accumulation in a rotenone mouse model of Parkinson's disease by Qi Hu; Vladimir N. Uversky; Mengyang Huang; Huicong Kang; Feng Xu; Xiaoyan Liu; Lifei Lian; Qiming Liang; Hong Jiang; Anding Liu; Cuntai Zhang; Francisco Pan-Montojo; Suiqiang Zhu (1883-1890).
Parkinson's disease (PD) is a progressive neurodegenerative disease. α-Synuclein (α-syn) oligomers play a critical role in the progression of PD. Baicalein, a typical flavonoid compound, can inhibit the formation of the α-syn oligomers, and disaggregate existing α-syn oligomers in vitro. However, whether baicalein could inhibit or disaggregate α-syn oligomers in vivo has not been investigated. Therefore, this study was designed to investigate the inhibitory effects of baicalein on α-syn oligomers in vivo and to explore the possible mechanisms of such inhibition. A chronic PD mouse model was created by continuous intragastric administration of rotenone (5 mg/kg, 12 weeks). Baicalein (100 mg/kg) was intraperitoneally injected from 7 week to 12 week. Our result showed that the amount of α-syn, changes in the levels of the striatal neurotransmitters, and the behavioral changes found in the chronic PD mouse model were prevented after the baicalein injections. Although baicalein did not decrease α-syn mRNA expression, α-syn oligomers were significantly decreased in the ileum, thoracic spinal cord, and midbrain. Furthermore, transmission electron microscopy analysis showed that baicalein could prevent α-syn monomers from the oligomer formation in vitro. Taken together, these results suggest that baicalein could prevent the progression of α-syn accumulation in PD mouse model partly by inhibiting formation of the α-syn oligomers.
Keywords: Baicalein; Flavonoid; Parkinson's disease; Neurodegenerative disease; α-Synuclein; Rotenone;
Dexamethasone-induced muscular atrophy is mediated by functional expression of connexin-based hemichannels by Luis A. Cea; Elisa Balboa; Carlos Puebla; Aníbal A. Vargas; Bruno A. Cisterna; Rosalba Escamilla; Tomás Regueira; Juan C. Sáez (1891-1899).
Long-term treatment with high glucocorticoid doses induces skeletal muscle atrophy. However, the molecular mechanism of such atrophy remains unclear. We evaluated the possible involvement of connexin-based hemichannels (Cx HCs) in muscle atrophy induced by dexamethasone (DEX), a synthetic glucocorticoid, on control (Cx43fl/flCx45fl/fl) and Cx43/Cx45 expression-deficient (Cx43fl/flCx45fl/fl:Myo-Cre) skeletal myofibers. Myofibers of Cx43fl/flCx45fl/fl mice treated with DEX (5 h) expressed several proteins that form non-selective membrane channels (Cx39, Cx43, Cx45, Panx1, P2X7 receptor and TRPV2). After 5 h DEX treatment in vivo, myofibers of Cx43fl/flCx45fl/fl mice showed Evans blue uptake, which was absent in myofibers of Cx43fl/flCx45fl/fl:Myo-Cre mice. Similar results were obtained in vitro using ethidium as an HC permeability probe, and DEX-induced dye uptake in control myofibers was blocked by P2X7 receptor inhibitors. DEX also induced a significant increase in basal intracellular Ca2 + signal and a reduction in resting membrane potential in Cx43fl/flCx45fl/fl myofibers, changes that were not elicited by myofibers deficient in Cx43/Cx45 expression. Moreover, treatment with DEX induced NFκB activation and increased mRNA levels of TNF-α in control but not in Cx43/Cx45 expression-deficient myofibers. Finally, a prolonged DEX treatment (7 days) increased atrogin-1 and Murf-1 and reduced the cross sectional area of Cx43fl/flCx45fl/fl myofibers, but these parameters remained unaffected in Cx43fl/flCx45fl/fl:Myo-Cre myofibers. Therefore, DEX-induced expression of Cx43 and Cx45 plays a critical role in early sarcolemma changes that lead to atrophy. Consequently, this side effect of chronic glucocorticoid treatment might be avoided by co-administration with a Cx HC blocker.
Keywords: Connexons; Membrane leakage; Ethidium bromide; Purinergic receptors; Glucocorticoids;
Chronic venous disease – Part II: Proteolytic biomarkers in wound healing by Daniela Ligi; Giovanni Mosti; Lidia Croce; Joseph D. Raffetto; Ferdinando Mannello (1900-1908).
Venous leg ulcers (VLU) are characterized by sustained proteolytic microenvironment impairing the healing process. Wound fluid (WF) reflect the biomolecular activities occurring within the wound area; however, it is unclear if WF from different healing phases have different proteolytic profiles and how VLU microenvironment affects the wound healing mechanisms. We investigated the proteolytic network of WF from distinct VLU phases, and in WF- and LPS-stimulated THP-1 monocytes treated with glycosaminoglycan sulodexide, a well known therapeutic approach for VLU healing.WF were collected from patients with VLU during inflammatory (Infl) and granulating (Gran) phases. WF and THP-1 supernatants were analyzed for nine matrix metalloproteinases (MMP) and four tissue inhibitors of metalloproteinases (TIMP) by multiplex immunoassays. Our results demonstrated that: 1) WF from Infl VLU contained significantly increased concentrations of MMP-2, MMP-9, MMP-12, TIMP-1, and TIMP-2 compared to Gran WF; 2) WF from Gran VLU showed significantly increased levels of MMP-1, MMP-7, MMP-13, and TIMP-4 compared to Infl WF; 3) LPS- and WF-stimulation of THP-1 cells significantly increased the expression of several MMP compared to untreated cells; 4) Sulodexide treatment of both LPS- and WF-stimulated THP-1 significantly down-regulated the release of several MMPs. Our study provides evidence-based medicine during treatment of patients with VLU. WF from Infl and Gran VLU have different MMP and TIMP signatures, consistent with their clinical state. The modulation of proteolytic pathways in wound microenvironment by glycosaminoglycan sulodexide, provide insights for translating research into clinical practice during VLU therapy.Display Omitted
Keywords: Chronic Venous Insufficiency; Wound healing; Glycosaminoglycan; Venous leg ulcer; Matrix metalloproteinase; Tissue inhibitors of metalloproteinase;
Mitochondrial traffic jams in Alzheimer's disease - pinpointing the roadblocks by Sónia C. Correia; George Perry; Paula I. Moreira (1909-1917).
The vigorous axonal transport of mitochondria, which serves to distribute these organelles in a dynamic and non-uniform fashion, is crucial to fulfill neuronal energetic requirements allowing the maintenance of neurons structure and function. Particularly, axonal transport of mitochondria and their spatial distribution among the synapses are directly correlated with synaptic activity and integrity. Despite the basis of Alzheimer's disease (AD) remains enigmatic, axonal pathology and synaptic dysfunction occur prior the occurrence of amyloid-β (Aβ) deposition and tau aggregation, the two classical hallmarks of this devastating neurodegenerative disease. Importantly, the early stages of AD are marked by defects on axonal transport of mitochondria as denoted by the abnormal accumulation of mitochondria within large swellings along dystrophic and degenerating neuritis. Within this scenario, this review is devoted to identify the molecular “roadblocks” underlying the abnormal axonal transport of mitochondria and consequent synaptic “starvation” and neuronal degeneration in AD. Understanding the molecular nature of defective mitochondrial transport may provide a new avenue to counteract AD pathology.
Keywords: Alzheimer's disease; Mitochondrial bioenergetics; Mitochondrial dynamics; Mitochondrial transport; Amyloid-β; Tau; Synapse;
Inhibition of IL-6 trans-signaling in the brain increases sociability in the BTBR mouse model of autism by Hongen Wei; Yuehong Ma; Jianrong Liu; Caiyun Ding; Guorong Jin; Yi Wang; Fengyun Hu; Li Yu (1918-1925).
Autism is a severe neurodevelopmental disorder with a large population prevalence, characterized by abnormal reciprocal social interactions, communication deficits, and repetitive behaviors with restricted interests. The BTBR T + Itpr3 tf (BTBR) mice have emerged as strong candidates to serve as models of a range of autism-relevant behaviors. Increasing evidences suggest that interleukin (IL)-6, one of the most important neuroimmune factors, was involved in the pathophysiology of autism. It is of great importance to further investigate whether therapeutic interventions in autism can be achieved through the manipulation of IL-6. Our previous studies showed that IL-6 elevation in the brain could mediate autistic-like behaviors, possibly through the imbalances of neural circuitry and impairments of synaptic plasticity. In this study, we evaluate whether inhibiting IL-6 signaling in the brain is sufficient to modulate the autism-like behaviors on the BTBR mice. The results showed that chronic infusion of an analog of the endogenous IL-6 trans-signaling blocker sgp130Fc protein increased the sociability in BTBR mice. Furthermore, no change was observed in the number of excitatory synapse, level of synaptic proteins, density of dentitic spine and postsynaptic density in BTBR cortices after inhibiting IL-6 trans-signaling. However, inhibition of IL-6 trans-signaling increased the evoked glutamate release in synaptoneurosomes from the cerebral cortex of BTBR mice. Our findings suggest that inhibition of excessive production of IL-6 may have selective therapeutic efficacy in treating abnormal social behaviors in autism.
Keywords: Autism; Sociability; IL-6; BTBR; Glutamate release;
Novel miR-5582-5p functions as a tumor suppressor by inducing apoptosis and cell cycle arrest in cancer cells through direct targeting of GAB1, SHC1, and CDK2 by Hyun-Ju An; Seo-Young Kwak; Je-Ok Yoo; Jae-Sung Kim; In-Hwa Bae; Myung-Jin Park; Mee-Yon Cho; Joon Kim; Young-Hoon Han (1926-1937).
MicroRNAs (miRNAs) play pivotal roles in tumorigenesis as either tumor suppressors or oncogenes. In the present study, we discovered and demonstrated the tumor suppressive function of a novel miRNA miR-5582-5p. miR-5582-5p induced apoptosis and cell cycle arrest in cancer cells, but not in normal cells. GAB1, SHC1, and CDK2 were identified as direct targets of miR-5582-5p. Knockdown of GAB1/SHC1 or CDK2 phenocopied the apoptotic or cell cycle arrest-inducing function of miR-5582-5p, respectively. The expression of miR-5582-5p was lower in tumor tissues than in adjacent normal tissues of colorectal cancer patients, while the expression of the target proteins exhibited patterns opposite to that of miR-5582-5p. Intratumoral injection of a miR-5582-5p mimic or induced expression of miR-5582-5p in tumor cells suppressed tumor growth in HCT116 xenografts. Collectively, our results suggest a novel tumor suppressive function for miR-5582-5p and its potential applicability for tumor control.Display Omitted
Keywords: MicroRNA; miR-5582-5p; Tumor suppressor; GAB1; SHC1; CDK2;
Basement membrane protein ladinin-1 and the MIF-CD44-β1 integrin signaling axis are implicated in laryngeal cancer metastasis by Marko Klobučar; Mirela Sedić; Peter Gehrig; Jonas Grossmann; Mario Bilić; Lana Kovač-Bilić; Krešimir Pavelić; Sandra Kraljević Pavelić (1938-1954).
Laryngeal squamous cell carcinoma (LSCC) is the most common form of malignant disease in the head and neck region characterized by frequent occurrence of metastases in the neck lymph nodes early in the disease onset. In the presented study, we performed quantitative proteomic profiling of patient-matched primary tumor and adjacent non-tumorous tissues derived from metastatic LSCC as to identify new protein candidates with potential diagnostic and therapeutic significance. Obtained results revealed for the first time involvement of the basement membrane protein ladinin-1 in laryngeal cancer metastases. Alterations in the cellular microenvironment that propel metastatic events in laryngeal cancer include activation of MIF-CD44-β1 integrin signal transduction pathway and induction of downstream signaling mediated by NF-κB and Src tyrosine kinase, which ultimately impinge on cytoskeletal dynamics and architecture resulting in increased cellular motility and invasiveness. In this context, particularly interesting finding is upregulation of several actin-binding proteins novel to laryngeal cancer pathogenesis including coronin-1C and plastin-2, whose functional significance in laryngeal carcinogenesis has yet to be established. We also detected for the first time a complete loss of afamin in metastatic laryngeal cancer tissues, which warrants further studies into its use as a possible marker for monitoring disease progression and/or treatment outcome.
Keywords: Squamous larynx cancer; Metastases; Proteomics; Ladinin-1; Src tyrosine kinase; Cytoskeleton;
Role of sphingomyelinase in mitochondrial ceramide accumulation during reperfusion by I. Ramírez-Camacho; R. Bautista-Pérez; F. Correa; M. Buelna-Chontal; N.G. Román-Anguiano; M. Medel-Franco; O.N. Medina-Campos; J. Pedraza-Chaverri; A. Cano-Martínez; C. Zazueta (1955-1963).
Ceramide accumulation in mitochondria has been associated with reperfusion damage, but the underlying mechanisms are not clearly elucidated. In this work we investigate the role of sphingomyelinases in mitochondrial ceramide accumulation, its effect on reactive oxygen species production, as well as on mitochondrial function by using the sphingomyelinase inhibitor, tricyclodecan-9-yl-xanthogenate (D609). Correlation between neutral sphingomyelinase (nSMase) activity and changes in ceramide content were performed in whole tissue and in isolated mitochondria from reperfused hearts. Overall results demonstrated that D609 treatment attenuates cardiac dysfuncion, mitochondrial injury and oxidative stress. Ceramide was accumulated in mitochondria, but not in the microsomal fraction of the ischemic-reperfused (I/R) group. In close association, the activity of nSMase increased, whereas glutathione (GSH) levels diminished in mitochondria after reperfusion. On the other hand, reduction of ceramide levels in mitochondria from I/R + D609 hearts correlated with diminished nSMase activity, coupling of oxidative phosphorylation and with mitochondrial integrity maintenance. These results suggest that mitochondrial nSMase activity contributes to compartmentation and further accumulation of ceramide in mitochondria, deregulating their function during reperfusion.
Keywords: Ceramide; Mitochondria; Sphingomyelinase;
Chronic venous disease – Part I: Inflammatory biomarkers in wound healing by Daniela Ligi; Giovanni Mosti; Lidia Croce; Joseph D. Raffetto; Ferdinando Mannello (1964-1974).
Venous leg ulcers (VLUs) produce wound fluid (WF), as a result of inflammatory processes within the wound. It is unclear if WF from different healing phases of VLU has a peculiar biochemical profile and how VLU microenvironment affects the wound healing mechanisms. This study was conducted to evaluate the cytokine/chemokine profiles in WF from distinct VLU phases, in WF- and LPS-stimulated monocytes and treated with glycosaminoglycan Sulodexide, a therapeutic option for VLU healing.WF and plasma were collected from patients with VLU during active inflammatory (Infl) and granulating (Gran) phases. Demographics, clinical characteristics and pain measurements were evaluated. WF, plasma, and THP-1 supernatants were analyzed for 27 inflammatory mediators by multiplex immunoassay. Our results demonstrated that: 1) pain was significantly increased in patients with Infl compared to Gran VLU; 2) cytokine profile of Infl WF was found to be statistically different from that Gran WF, as well significantly increased respect to plasma; 3) LPS- and WF-stimulation of THP-1 cells significantly increased the expression of several cytokines compared to untreated cells; 4) Sulodexide treatment of both LPS- and WF-stimulated THP-1 monocytes was able to significantly down-regulate the release of peculiar inflammatory mediators.Our study highlighted the importance to understand biomolecular processes underlying CVI when providing treatment for chronic VLU. Identification of inflammatory biomarkers in leg ulcer microenvironment, may provide useful tools for predicting healing outcome and developing targeted therapies.Display Omitted
Keywords: Chronic venous insufficiency; Inflammation; Glycosaminoglycan; Sulodexide; Venous leg ulcer; Wound healing;
Staphylococcus aureus protein A enhances osteoclastogenesis via TNFR1 and EGFR signaling by Andrea Mendoza Bertelli; María Victoria Delpino; Santiago Lattar; Constanza Giai; Mariángeles Noto Llana; Norberto Sanjuan; James E. Cassat; Daniel Sordelli; Marisa I. Gómez (1975-1983).
Staphylococcus aureus is a major causative agent of osteomyelitis in adults and children. The increasing incidence of antimicrobial resistant isolates and the morbidity of this type of infection denote that alternative therapeutic approaches are required. S. aureus protein A interacts with TNFR1 and EGFR expressed at the surface of host cells. Given the importance of TNF-α and EGFR/RANKL crosstalk in enhancing osteoclast differentiation, the aim of this study was to determine the role of protein A in the induction of osteoclastogenesis and bone resorption during staphylococcal osteomyelitis. We determined that protein A plays a critical role in osteoclast differentiation and activation by initiating TNFR1 and EGFR mediated signaling. Moreover, we demonstrated that protein A significantly contributes to increased osteoclast differentiation and activation as well as cortical bone destruction during the course of disease using experimental models of osteomyelitis. Our findings strongly suggest targeting protein A and TNFR1 as an adjunctive strategy to control bone damage during the initial course of S. aureus osteomyelitis.
Keywords: Staphylococcus aureus; Protein A; Osteoclastogenesis; TNFR1; EGFR;
Peripheral biomarkers of stroke: Focus on circulatory microRNAs by Murali Vijayan; P. Hemachandra Reddy (1984-1993).
Stroke is the second leading cause of death in the world. Stroke occurs when blood flow stops, and that stoppage results in reduced oxygen supply to neurons in the brain. The occurrence of stroke increases with age, but anyone at any age can suffer from stroke. Recent research has implicated multiple cellular changes in stroke patients, including oxidative stress and mitochondrial dysfunction, inflammatory responses, and changes in mRNA and proteins. Recent research has also revealed that stroke is associated with modifiable and non-modifiable risk factors. Stroke can be controlled by modifiable risk factors, including diet, cardiovascular, hypertension, smoking, diabetes, obesity, metabolic syndrome, depression and traumatic brain injury. Stroke is the major risk factor for vascular dementia (VaD) and Alzheimer's disease (AD). The purpose of this article is to review the latest developments in research efforts directed at identifying 1) latest developments in identifying biomarkers in peripheral and central nervous system tissues, 2) changes in microRNAs (miRNAs) in patients with stroke, 3) miRNA profile and function in animal brain, and 4) protein biomarkers in ischemic stroke. This article also reviews research investigating circulatory miRNAs as peripheral biomarkers of stroke.
Keywords: Stroke; Vascular dementia; Alzheimer's disease; Circulatory microRNA; Serum; Plasma; Protein biomarker;
pH-sensitive K+ channel TREK-1 is a novel target in pancreatic cancer by Daniel R.P. Sauter; Christiane E. Sørensen; Markus Rapedius; Andrea Brüggemann; Ivana Novak (1994-2003).
Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers and new therapeutic targets are urgently needed. One of the hallmarks of cancer is changed pH-homeostasis and potentially pH-sensors may play an important role in cancer cell behavior. Two-pore potassium channels (K2P) are pH-regulated channels that conduct a background K+ current, which is involved in setting the plasma membrane potential (Vm). Some members of the K2P superfamily were reported as crucial players in driving tumor progression. The aim of this study was to investigate pH-regulated K+ currents in PDAC cells and determine possible effects on their pathological phenotype. Using a planar high-throughput patch-clamp system (SyncroPatch 384PE) we identified a pH-regulated K+ current in the PDAC cell line BxPC-3. The current was inhibited by extracellular acidification and intracellular alkalization. Exposure to a set of different K+ channel inhibitors, and the TREK-1 (K2P2.1)–specific activator BL1249, TREK-1 was identified as the main component of pH-regulated current. A voltage-sensor dye (VF2.1.Cl) was used to monitor effects of pH and BL1249 on Vm in more physiological conditions and TREK-1–mediated current was found as critical player in setting Vm. We assessed a possible role of TREK-1 in PDAC progression using cell proliferation and migration assays and observed similar trends with attenuated proliferation/migration rates in acidic (pH < 7.0) and alkaline (pH > 7.4) conditions. Notably, BL1249 inhibited both PDAC cell proliferation and migration indicating that hyperpolarization of Vm attenuates cancer cell behavior. TREK-1 may therefore be a promising novel target for PDAC therapy.
Keywords: K2P channel; K+ channel; BL1249; Pancreatic adenocarcinoma; Proliferation; Migration;
Proteomic analysis of FUS interacting proteins provides insights into FUS function and its role in ALS by Marisa Kamelgarn; Jing Chen; Lisha Kuang; Alexandra Arenas; Jianjun Zhai; Haining Zhu; Jozsef Gal (2004-2014).
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease. Mutations in the Fused in Sarcoma/Translocated in Liposarcoma (FUS/TLS) gene cause a subset of familial ALS cases and are also implicated in sporadic ALS. FUS is typically localized to the nucleus. The ALS-related FUS mutations cause cytoplasmic mis-localization and the formation of stress granule-like structures. Abnormal cytoplasmic FUS localization was also found in a subset of frontotemporal dementia (FTLD) cases without FUS mutations. To better understand the function of FUS, we performed wild-type and mutant FUS pull-downs followed by proteomic identification of the interacting proteins. The FUS interacting partners we identified are involved in multiple pathways, including chromosomal organization, transcription, RNA splicing, RNA transport, localized translation, and stress response. FUS interacted with hnRNPA1 and Matrin-3, RNA binding proteins whose mutations were also reported to cause familial ALS, suggesting that hnRNPA1 and Matrin-3 may play common pathogenic roles with FUS. The FUS interactions displayed varied RNA dependence. Numerous FUS interacting partners that we identified are components of exosomes. We found that FUS itself was present in exosomes, suggesting that the secretion of FUS might contribute to the cell-to-cell spreading of FUS pathology. FUS interacting proteins were sequestered into the cytoplasmic mutant FUS inclusions that could lead to their mis-regulation or loss of function, contributing to ALS pathogenesis. Our results provide insights into the physiological functions of FUS as well as important pathways where mutant FUS can interfere with cellular processes and potentially contribute to the pathogenesis of ALS.
Keywords: ALS; FUS; Proteomics; Protein interaction network; Neurodegeneration;
Increased aquaporin 1 and 5 membrane expression in the lens epithelium of cataract patients by Olatz Barandika; Maitane Ezquerra-Inchausti; Ander Anasagasti; Ainara Vallejo-Illarramendi; Irantzu Llarena; Lucia Bascaran; Txomin Alberdi; Giacomo De Benedetti; Javier Mendicute; Javier Ruiz-Ederra (2015-2021).
In this work we have analyzed the expression levels of the main aquaporins (AQPs) expressed in human lens epithelial cells (HLECs) using 112 samples from patients treated with cataract surgery and 36 samples from individuals treated with refractive surgery, with transparent lenses as controls. Aquaporin-1 (AQP1) is the main AQP, representing 64.1% of total AQPs in HLECs, with aquaporin-5 (AQP5) representing 35.9% in controls. A similar proportion of each AQP in cataract was found. Although no differences were found at the mRNA level compared to controls, a significant 1.65-fold increase (p = 0.001) in AQP1protein expression was observed in HLECs from cataract patients, with the highest differences being found for nuclear cataracts (2.1-fold increase; p < 0.001). A similar trend was found for AQP5 (1.47-fold increase), although the difference was not significant (p = 0.161). Moreover we have shown increased membrane AQP5 protein expression in HLECs of patients with cataracts. No association of AQP1 or AQP5 expression levels with age or sex was observed in either group. Our results suggest regulation of AQP1 and AQP5 at the post-translational level and support previous observations on the implication of AQP1 and 5 in maintenance of lens transparency in animal models. Our results likely reflect a compensatory response of the crystalline lens to delay cataract formation by increasing the water removal rate.
Keywords: Cataract; Lens transparency; Aquaporins; AQP1; AQP5;