A C-terminally truncated form of β-catenin acts as a novel regulator of Wnt/β-catenin signaling in planarians

β-Catenin, the core element of the Wnt/β-catenin pathway, is a multifunctional and evolutionarily conserved protein which performs essential roles in a variety of developmental and homeostatic processes. Despite its crucial roles, the mechanisms that control its context-specific functions in time and space remain largely unknown. The Wnt/β-catenin pathway has been extensively studied in planarians, flatworms with the ability to regenerate and remodel the whole body, providing a 'whole animal' developmental framework to approach this question. Here we identify a C-terminally truncated β-catenin (β-catenin4), generated by gene duplication, that is required for planarian photoreceptor cell specification. Our results indicate that the role of β-catenin4 is to modulate the activity of β-catenin1, the planarian β-catenin involved in Wnt signal transduction in the nucleus, mediated by the transcription factor TCF-2. This inhibitory form of β-catenin, expressed in specific cell types, would provide a novel mechanism to modulate nuclear β-catenin signaling levels. Genomic searches and in vitro analysis suggest that the existence of a C-terminally truncated form of β-catenin could be an evolutionarily conserved mechanism to achieve a fine-tuned regulation of Wnt/β-catenin signaling in specific cellular contexts

The CD200R1 Microglial inhibitory receptor as a therapeutic target in the MPTP model of Parkinson's disease

Background It is suggested that neuroinflammation, in which activated microglial cells play a relevant role, contributes to the development of Parkinson's disease (PD). Consequently, the modulation of microglial activation is a potential therapeutic target to be taken into account to act against the dopaminergic neurodegeneration occurring in this neurological disorder. Several soluble and membrane-associated inhibitory mechanisms contribute to maintaining microglial cells in a quiescent/surveillant phenotype in physiological conditions. However, the presence of activated microglial cells in the brain in PD patients suggests that these mechanisms have been somehow overloaded. We focused our interest on one of the membrane-associated mechanisms, the CD200-CD200R1 ligand-receptor pair. Methods The acute MPTP experimental mouse model of PD was used to study the temporal pattern of mRNA expression of CD200 and CD200R1 in the context of MPTP-induced dopaminergic neurodegeneration and neuroinflammation. Dopaminergic damage was assessed by tyrosine hydroxylase (TH) immunoreactivity, and neuroinflammation was evaluated by the mRNA expression of inflammatory markers and IBA1 and GFAP immunohistochemistry. The effect of the modulation of the CD200-CD200R1 system on MPTP-induced damage was determined by using a CD200R1 agonist or CD200 KO mice. Results MPTP administration resulted in a progressive decrease in TH-positive fibres in the striatum and TH-positive neurons in the substantia nigra pars compacta, which were accompanied by transient astrogliosis, microgliosis and expression of pro- and anti-inflammatory markers. CD200 mRNA levels rapidly decreased in the ventral midbrain after MPTP treatment, while a transient decrease of CD200R1 mRNA expression was repeatedly observed in this brain area at earlier and later phases. By contrast, a transient increase in CD200R1 expression was observed in striatum. The administration of a CD200R1 agonist resulted in the inhibition of MPTP-induced dopaminergic neurodegeneration, while microglial cells showed signs of earlier activation in CD200-deficient mice. Conclusions Collectively, these findings provide evidence for a correlation between CD200-CD200R1 alterations, glial activation and neuronal loss. CD200R1 stimulation reduces MPTP-induced loss of dopaminergic neurons, and CD200 deficiency results in earlier microglial activation, suggesting that the potentiation of CD200R1 signalling is a possible approach to controlling neuroinflammation and neuronal death in PD

Parkinsonian neurotoxicants impair the anti-inflammatory response induced by IL4 in glial cells: involvement of the CD200-CD200R1 ligand-receptor pair

Exposure to pesticides such as rotenone is a risk factor for Parkinson's disease. Dopaminergic neurons are especially sensitive to the toxicity of compounds that inhibit the mitochondrial respiratory chain such as rotenone and 1-methyl-4-phenylpyridinium (MPP+). However, there is scarce information on their effects on glia. To evaluate whether these neurotoxicants affect the immune response of glia, primary mouse mixed glial and microglial cultures were treated with interleukin (IL) 4 in the absence and presence of MPP+ or rotenone. Using qRTPCR or western blot, we determined the expression of anti-inflammatory markers, the CD200R1 microglial receptor and its ligand CD200, and genes regulating glycolysis and oxidative metabolism. ATP and lactate levels were additionally determined as an index of cell metabolism. Microglial phagocytosis was also evaluated. MPP+ and rotenone clearly abrogated the IL4-induced expression of anti-inflammatory markers in mixed glial cultures. CD200 and CD200R1 expression and microglia phagocytosis were also affected by the neurotoxicants. Changes in the mRNA expression of the molecules regulating glycolysis and oxidative metabolism, as well as in ATP levels and lactate release suggested that metabolic reprogramming in response to MPP+ and rotenone differs between microglial and mixed glial cultures. These findings support the hypothesis that parkinsonian neurotoxicants may impair brain immune response altering glial cell metabolism

Mesoporous silica particles are phagocytosed by microglia and induce a mild inflammatory response in vitro

Aim: Mesoporous silica particles (MSPs) are broadly used drug delivery carriers. In this study, the authors analyzed the responses to MSPs of astrocytes and microglia, the two main cellular players in neuroinflammation. Materials & methods: Primary murine cortical mixed glial cultures were treated with rhodamine B-labeled MSPs. Results: MSPs are avidly internalized by microglial cells and remain inside the cells for at least 14 days. Despite this, MSPs do not affect glial cell viability or morphology, basal metabolic activity or oxidative stress. MSPs also do not affect mRNA levels of key proinflammatory genes; however, in combination with lipopolysaccharide, they significantly increase extracellular IL-1β levels. Conclusion: These results suggest that MSPs could be novel tools for specific drug delivery to microglial cells. Plain language summary Mesoporous silica particles (MSPs) are broadly used drug delivery carriers. In this study, the authors analyzed the responses of two types of brain cells, astrocytes and microglia, to MSPs. Mouse astrocytes and microglia were kept alive in cultures and were treated with MSPs that were labeled with a red fluorescent agent to facilitate visualization under the microscope. MSPs are avidly internalized by microglial cells and remain inside the cells for at least 14 days. Despite this, MSPs do not affect glial cell viability or morphology, basal metabolic activity or oxidative stress. When given alone, MSPs do not affect mRNA levels of key proinflammatory genes. However, MSPs given in combination with lipopolysaccharide, a strong proinflammatory agent, significantly increase extracellular levels of IL-1β, one of the proinflammatory mediators studied. These results suggest that MSPs could be novel tools for specific drug delivery to microglial cells

Stroke-associated pneumonia according to mCDC criteria: impact on prognosis and antibiotic therapy

Antibiotics; Infections; Stroke-associated pneumoniaAntibióticos; Infecciones; Neumonía asociada a ictusAntibiòtics; Infeccions; Pneumònia associada a ictusObjective: The modified Centers for Disease Control and Prevention (mCDC) criteria have been proposed for diagnosing and managing stroke-associated pneumonia (SAP). The objective was to investigate the impact of SAP on stroke outcome depending on whether or not it conforms to mCDC criteria. Our secondary objective was to identify the responsible factors for antibiotic initiation in stroke patients. Methods: We conducted a prospective, multicenter, observational study of ischemic stroke patients with moderate to severe stroke (NIHSS≥4) admitted within 24 h. For 7 days, mCDC criteria were assessed daily, and infections and antibiotics were recorded. Pneumonias were divided into those fulfilling mCDC criteria (mCDC-SAP) or not (other pneumonias, OPn). The effect of each type of pneumonia on 3-month outcome was evaluated in separated logistic regression models. Factors associated with antibiotic initiation were explored using a random forest analysis. Results: Of the 342 patients studied, infections were diagnosed in 72 (21.6%), including 39 (11.7%) cases of pneumonia. Of them, 25 (7.5%) fulfilled mCDC criteria. Antibiotics were used in 92% of mCDC-SAP and 64.3% of OPn. In logistic regression analysis, mCDC-SAP, but not OPn, was an independent predictor of poor outcome [OR, 4.939 (1.022–23.868)]. The random forest analysis revealed that fever had the highest importance for antibiotic initiation. Interpretation: The mCDC criteria might be useful for detecting clinically relevant SAP, which is associated with poor outcomes. Isolated signs of infection were more important for antibiotic initiation than compliance with pre-defined criteria. Therefore, adherence to mCDC criteria might result in antibiotic saving without compromising clinical outcome.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. Study supported by Fundació La Marató de TV3 (201706-30-31), Instituto de Salud Carlos III (PI17/02130 and PI21/00949), co-financed by the Fondo Europeo de Desarrollo Regional. Some centres take part in Spanish Stroke Research Network RICORS-ICTUS (RD21/0006/0024, RD21/0006/0007 and RD21/0006/0015)

Toxic and nutritional factors trigger Leber hereditary optic neuropathy due to a mitochondrial tRNA mutation

Leber hereditary optic neuropathy is a mitochondrial disease mainly due to pathologic mutations in mitochondrial genes related to the respiratory complex I of the oxidative phosphorylation system. Genetic, physiological, and environmental factors modulate the penetrance of these mutations. We report two patients suffering from this disease and harboring a m.15950G > A mutation in the mitochondrial DNA-encoded gene for the threonine transfer RNA. We also provide evidences supporting the pathogenicity of this mutation

Medicalized Hotel as an Alternative to Hospital Care for Management of Noncritical COVID-19

Background: Since the first wave of COVID-19, alternatives to conventional hospitalization have been proposed for the provision of different levels of care, ranging from shelter during quarantine to hospital-level medical care. Objective: To describe the adaptation of a hotel by a hospital-at-home team to provide hospital-level care to patients with COVID-19 during the first wave of the pandemic in Barcelona, Spain. Methods: Hospital Clínic de Barcelona (HCB) is a 750-bed, public, tertiary teaching hospital serving 560 000 persons in the metropolitan area of Barcelona, Spain. In March 2020, the hospital-at-home unit was instructed to medicalize a hotel ('health hotel' [HH]) in downtown Barcelona. The aim of this initiative was to help decongest hospitals in the area by admitting patients with low dependency (Barthel Index score >60) and mild to severe COVID-19 from emergency departments or COVID-19 hospital wards, according to Centers for Disease Control and Prevention clinical guideline

Spanish cohort of VEXAS syndrome : clinical manifestations, outcome of treatments and novel evidences about UBA1 mosaicism

The vacuoles, E1-enzyme, X linked, autoinflammatory and somatic (VEXAS) syndrome is an adult-onset autoinflammatory disease (AID) due to postzygotic UBA1 variants. To investigate the presence of VEXAS syndrome among patients with adult-onset undiagnosed AID. Additional studies evaluated the mosaicism distribution and the circulating cytokines. Gene analyses were performed by both Sanger and amplicon-based deep sequencing. Patients' data were collected from their medical charts. Cytokines were quantified by Luminex. Genetic analyses of enrolled patients (n=42) identified 30 patients carrying UBA1 pathogenic variants, with frequencies compatible for postzygotic variants. All patients were male individuals who presented with a late-onset disease (mean 67.5 years; median 67.0 years) characterised by cutaneous lesions (90%), fever (66.7%), pulmonary manifestations (66.7%) and arthritis (53.3%). Macrocytic anaemia and increased erythrocyte sedimentation rate and ferritin were the most relevant analytical abnormalities. Glucocorticoids ameliorated the inflammatory manifestations, but most patients became glucocorticoid-dependent. Positive responses were obtained when targeting the haematopoietic component of the disease with either decitabine or allogeneic haematopoietic stem cell transplantation. Additional analyses detected the UBA1 variants in both haematopoietic and non-haematopoietic tissues. Finally, analysis of circulating cytokines did not identify inflammatory mediators of the disease. Thirty patients with adult-onset AID were definitively diagnosed with VEXAS syndrome through genetic analyses. Despite minor interindividual differences, their main characteristics were in concordance with previous reports. We detected for the first time the UBA1 mosaicism in non-haematopoietic tissue, which questions the previous concept of myeloid-restricted mosaicism and may have conceptual consequences for the disease mechanisms

Brain immune response as therapeutic target in the treatment of Parkinson’s disease

[eng] Neuroinflammation is present in practically all neurological disorders. Microglial cells, the main representatives of the endogenous immune system of the brain, play a key role in neuroinflammation, although peripheral immune cells can also be involved. In the last years, a considerable effort has been focused on the study of the modulation of the inflammatory response as a possible therapeutic strategy in neurological diseases. Parkinson’s disease (PD) is the second most common neurodegenerative disease and is mainly characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and an abnormal intracellular accumulation of α-synuclein protein, known as Lewy bodies. Mounting evidence suggests that dopaminergic cell death is influenced by the innate immune system. Activated microglia has been described in the post-mortem brains of PD patients; however, the pathogenic role of the immune system in PD remains enigmatic. In the present thesis, we have studied one of the inhibitory mechanisms suggested to be involved in the control of the inflammatory response in microglial cells: CD200 ligand (mainly expressed in neurons and astrocytes) - CD200R1 receptor (mainly microglial) interaction. The aim of this thesis was to study the involvement of the microglial inhibitory immune receptor CD200R1 in the modulation of neuroinflammation and its potential as therapeutic target in PD. In vitro, the disruption of the CD200-CD200R1 system potentiated the pro-inflammatory response of glial cells. Mesencephalic cultures from CD200-deficient mice showed a higher microglial proportion and increased sensitivity of dopaminergic neurons to the neurotoxin 1-methyl-4- phenylpyridinium (MPP+). The parkinsonian neurotoxins MPP+ and rotenone impaired the immune response of glial cells to pro- and anti-inflammatory stimuli and changed CD200 and CD200R1 expression. In vivo, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) experimental mouse model of PD dopaminergic neurodegeneration and glial activation were associated to changes in CD200 and CD200R1 expression: mainly a transient increase in striatal CD200R1 and a sustained decrease in CD200full in the ventral midbrain. When we potentiated the CD200-CD200R1 system by administering a CD200R1 agonist, we observed partial protection in dopaminergic neurons of the SNpc, which was accompanied by an attenuated microglial activation. On the contrary, CD200-deficient mice showed a more reactive microglial phenotype at early stages after MPTP administration, although it was not associated to an exacerbated neurodegeneration. Post-mortem brain samples from substantia nigra, frontal cortex and hippocampus of PD patients had particular changes in the expression of the mRNA variants and protein isoforms of the CD200-CD200R1 system. In conclusion, these results suggest that the CD200-CD200R1 system is a potential target to control microglial activation in PD, and that the mechanisms of control of microglial activation may be used to modulate microglial activation and its potential neurotoxicity on neurodegenerative diseases.[spa] La neuroinflamació està present en pràcticament tots els desordres neurològics i la micròglia hi juga un paper clau. La malaltia de Parkinson (MP) és la segona malaltia neurodegenerativa més comú i està caracteritzada per la pèrdua de neurones dopaminèrgiques de la part compacta de la substancia negra (SNpc) i la presència de cossos de Lewy. Hi ha evidència de que la neurodegeneració dopaminèrgica està influenciada pel sistema immunitari innat. En aquesta tesi, hem estudiat un dels mecanismes inhibitoris suggerits d’estar involucrats en el control de la resposta inflamatòria de la micròglia: el lligand CD200 (principalment neuronal i astrocític) i el receptor CD200R1 (principalment microglial). La finalitat era estudiar el rol de CD200R1 en la modulació de la neuroinflamació i el seu potencial com a diana terapèutica en la MP. In vitro, la disrupció del sistema CD200-CD200R1 va potenciar la resposta pro-inflamatòria glial. Cultius mesencefàlics de ratolins deficients en CD200 van mostra una major proporció de micròglia i una sensibilitat incrementada de les neurones dopaminèrgiques al 1-metil-4- fenilpiridina (MPP+). Les neurotoxines parkinsonianes MPP+ i rotenona van alterar la resposta glial a estímuls inflamatoris i van modificar l’expressió de CD200 i CD200R1. In vivo, en el model de ratolí de la MP amb 1-metil-4-fenil,6-tetrahidropiridina (MPTP) la mort dopaminèrgica i l’activació glial es van associar a un increment transitori de CD200R1 estriatal i una disminució sostinguda de CD200full en el mesencèfal ventral. L’administració d’un agonista de CD200R1 va protegir parcialment les neurones dopaminèrgiques de la SNpc i va atenuar l’activació microglial. Contràriament, ratolins deficients en CD200 van mostrar un fenotip microglial més reactiu en estadis inicials després de l’administració del MPTP, encara que no es va associar a una neurodegeneració exacerbada. A mostres de cervell post-mortem de la SN, còrtex frontal i hipocamp de pacients amb MP es van observar canvis en l’expressió de les variants de RNA i les isoformes proteiques del sistema CD200-CD200R1. En conclusió, aquests resultats suggereixen que el sistema CD200-CD200R1 és una diana potencial pel control de l’activació microglial en la MP, i que els mecanismes de control de l’activació microglial podrien ser usats per modular l’activació microglial i el seu potencial neurotòxic en les malalties neurodegeneratives

Brain immune response as therapeutic target in the treatment of parkinson's disease

Tesis llevada a cabo para conseguir el grado de Doctor por la Universidad de Barcelona.--2019-07-22.--Excelente Cum Laudem[EN] Neuroinflammation is present in practically all neurological disorders. Microglial cells, the main representatives of the endogenous immune system of the brain, play a key role in neuroinflammation, although peripheral immune cells can also be involved. In the last years, a considerable effort has been focused on the study of the modulation of the inflammatory response as a possible therapeutic strategy in neurological diseases. Parkinson’s disease (PD) is the second most common neurodegenerative disease and is mainly characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and an abnormal intracellular accumulation of α-synuclein protein, known as Lewy bodies. Mounting evidence suggests that dopaminergic cell death is influenced by the innate immune system. Activated microglia has been described in the post-mortem brains of PD patients; however, the pathogenic role of the immune system in PD remains enigmatic. In the present thesis, we have studied one of the inhibitory mechanisms suggested to be involved in the control of the inflammatory response in microglial cells: CD200 ligand (mainly expressed in neurons and astrocytes) - CD200R1 receptor (mainly microglial) interaction. The aim of this thesis was to study the involvement of the microglial inhibitory immune receptor CD200R1 in the modulation of neuroinflammation and its potential as therapeutic target in PD. In vitro, the disruption of the CD200-CD200R1 system potentiated the pro-inflammatory response of glial cells. Mesencephalic cultures from CD200-deficient mice showed a higher microglial proportion and increased sensitivity of dopaminergic neurons to the neurotoxin 1-methyl-4- phenylpyridinium (MPP+). The parkinsonian neurotoxins MPP+ and rotenone impaired the immune response of glial cells to pro- and anti-inflammatory stimuli and changed CD200 and CD200R1 expression. In vivo, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) experimental mouse model of PD dopaminergic neurodegeneration and glial activation were associated to changes in CD200 and CD200R1 expression: mainly a transient increase in striatal CD200R1 and a sustained decrease in CD200full in the ventral midbrain. When we potentiated the CD200-CD200R1 system by administering a CD200R1 agonist, we observed partial protection in dopaminergic neurons of the SNpc, which was accompanied by an attenuated microglial activation. On the contrary, CD200-deficient mice showed a more reactive microglial phenotype at early stages after MPTP administration, although it was not associated to an exacerbated neurodegeneration. xx Post-mortem brain samples from substantia nigra, frontal cortex and hippocampus of PD patients had particular changes in the expression of the mRNA variants and protein isoforms of the CD200-CD200R1 system. In conclusion, these results suggest that the CD200-CD200R1 system is a potential target to control microglial activation in PD, and that the mechanisms of control of microglial activation may be used to modulate microglial activation and its potential neurotoxicity on neurodegenerative diseases.[ES] La neuroinflamación está presente en prácticamente todos los desórdenes neurológicos. Las células microgliales, los principales representantes del sistema immune endógeno del cerebro, juegan un papel clave en la neuroinflamación, aunque células del sistema immune periférico también pueden estar involucradas. En los últimos años, un considerable número de estudios se ha centrado en la modulación de la respuesta inflamatoria como posible estrategia terapéutica en las enfermedades neurológicas. La Enfermedad de Parkinson es la segunda enfermedad neurodegenerativa más común y está caracterizada principalmente por la pérdida de neuronas dopaminérgicas de la sustancia nigra pars compacta (SNpc) y una acumulación intracelular anormal de la proteína o-sinucleina, conocida como Cuerpos de Lewy. Evidencias científicas sugieren que la muerte de células dopaminérgicas está influenciada por el sistema immune innato. La microglia activada se ha descrito en muestras cerebrales post-mortem de pacientes diagnosticados de la Enfermedad de Parkinson; aún y así el rol patogénico del sistema immune en la Enfermedad de Parkinson permanece enigmático. En la presente tesis, hemos estudiado uno de los mecanismos inhibitorios sugerido de estar involucrado en el control de la respuesta inflamatoria microglial: la interacción del ligando CD200 (expresado principalmente en neuronas y astrocitos) con el receptor CD200Rl (principalmente microglial). El principal objetivo de esta tesis fue estudiar la implicación del receptor immune inhibitorio microglial CD200R1 en la modulación de fa neuroinflamación y su potencial como diana terapéutica en la Enfermedad de Parkinson. In vitro, la disrupción del sistema CD200-CD200Rl potenció la respuesta pro­ inflamatoria de las células gliales. Cultivos de mesencéfalo de ratones deficientes en CD200 mostró una proporción mayor de microglia y una sensibilidad incrementada de las neuronas dopaminérgicas a la neurotoxina 1-metil-4-fenilpiridinio (MPP+ ). Las neurotoxinas parkinsonianas MPP+ y rotenona alteraron la respuesta immune de las células gliales a estímulos pro- y anti- inflamatorios y produjeron cambios en la expresión de CD200 y CD200Rl. In vivo, en el modelo experimental de ratón de la Enfermedad de Parkinson 1-metil-4-fenil-1,2,3,6 tetrahidropiridina (MPTP) la neurodegeneración dopaminérgica y la activación glial se asociaron a cambios en la expresión de CD200 y CD20DR1: principalmente una subida de la expresión de CD200Rl en el estriado y una disminución sostenida de la expresión de CD200 en el mesencéfalo ventral. Cuando potenciamos el sistema CD200-CD200R1 con la administración de un agonista CD200Rl, observamos una protección parcial de las neuronas dopaminérgicas en la SNpc acompañada de una atenuación de la activación microglial. Por el contrario, ratones deficientes en CD200 mostraron un fenotipo microglial más reactivo a estadios tempranos después de la administración del MPTP, aunque esto no se asoció a una exacerbación de la neurodegeneración. Muestras cerebrales post-mortem de la sustancia nigra, córtex frontal e hipocampo de pacientes con la Enfermedad de Parkinson mostraron cambios particulares en la expresión de las variantes de ARNm y las isoformas proteicas que componen el sistema CD200-CD200Rl