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1.
Acta Neuropathol Commun ; 12(1): 73, 2024 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-38715119

RESUMEN

BACKGROUND: Neuroinflammation and Alzheimer's disease (AD) co-pathology may contribute to disease progression and severity in dementia with Lewy bodies (DLB). This study aims to clarify whether a different pattern of neuroinflammation, such as alteration in microglial and astroglial morphology and distribution, is present in DLB cases with and without AD co-pathology. METHODS: The morphology and load (% area of immunopositivity) of total (Iba1) and reactive microglia (CD68 and HLA-DR), reactive astrocytes (GFAP) and proteinopathies of alpha-synuclein (KM51/pser129), amyloid-beta (6 F/3D) and p-tau (AT8) were assessed in a cohort of mixed DLB + AD (n = 35), pure DLB (n = 15), pure AD (n = 16) and control (n = 11) donors in limbic and neocortical brain regions using immunostaining, quantitative image analysis and confocal microscopy. Regional and group differences were estimated using a linear mixed model analysis. RESULTS: Morphologically, reactive and amoeboid microglia were common in mixed DLB + AD, while homeostatic microglia with a small soma and thin processes were observed in pure DLB cases. A higher density of swollen astrocytes was observed in pure AD cases, but not in mixed DLB + AD or pure DLB cases. Mixed DLB + AD had higher CD68-loads in the amygdala and parahippocampal gyrus than pure DLB cases, but did not differ in astrocytic loads. Pure AD showed higher Iba1-loads in the CA1 and CA2, higher CD68-loads in the CA2 and subiculum, and a higher astrocytic load in the CA1-4 and subiculum than mixed DLB + AD cases. In mixed DLB + AD cases, microglial load associated strongly with amyloid-beta (Iba1, CD68 and HLA-DR), and p-tau (CD68 and HLA-DR), and minimally with alpha-synuclein load (CD68). In addition, the highest microglial activity was found in the amygdala and CA2, and astroglial load in the CA4. Confocal microscopy demonstrated co-localization of large amoeboid microglia with neuritic and classic-cored plaques of amyloid-beta and p-tau in mixed DLB + AD cases. CONCLUSIONS: In conclusion, microglial activation in DLB was largely associated with AD co-pathology, while astrocytic response in DLB was not. In addition, microglial activity was high in limbic regions, with prevalent AD pathology. Our study provides novel insights into the molecular neuropathology of DLB, highlighting the importance of microglial activation in mixed DLB + AD.


Asunto(s)
Enfermedad de Alzheimer , Astrocitos , Enfermedad por Cuerpos de Lewy , Microglía , Enfermedades Neuroinflamatorias , Humanos , Enfermedad por Cuerpos de Lewy/patología , Enfermedad por Cuerpos de Lewy/metabolismo , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/metabolismo , Femenino , Masculino , Anciano , Anciano de 80 o más Años , Enfermedades Neuroinflamatorias/patología , Enfermedades Neuroinflamatorias/metabolismo , Microglía/patología , Microglía/metabolismo , Astrocitos/patología , Astrocitos/metabolismo , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo , Antígenos CD/metabolismo , Péptidos beta-Amiloides/metabolismo , Persona de Mediana Edad , Antígenos de Diferenciación Mielomonocítica/metabolismo , Encéfalo/patología , Encéfalo/metabolismo , Molécula CD68
2.
Acta Neuropathol ; 147(1): 67, 2024 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-38581586

RESUMEN

Transcription factor EB (TFEB) is a master regulator of genes involved in the maintenance of autophagic and lysosomal homeostasis, processes which have been implicated in the pathogenesis of GBA-related and sporadic Parkinson's disease (PD), and dementia with Lewy bodies (DLB). TFEB activation results in its translocation from the cytosol to the nucleus. Here, we investigated TFEB subcellular localization and its relation to intracellular alpha-synuclein (aSyn) accumulation in post-mortem human brain of individuals with either incidental Lewy body disease (iLBD), GBA-related PD/DLB (GBA-PD/DLB) or sporadic PD/DLB (sPD/DLB), compared to control subjects. We analyzed nigral dopaminergic neurons using high-resolution confocal and stimulated emission depletion (STED) microscopy and semi-quantitatively scored the TFEB subcellular localization patterns. We observed reduced nuclear TFEB immunoreactivity in PD/DLB patients compared to controls, both in sporadic and GBA-related cases, as well as in iLBD cases. Nuclear depletion of TFEB was more pronounced in neurons with Ser129-phosphorylated (pSer129) aSyn accumulation in all groups. Importantly, we observed previously-unidentified TFEB-immunopositive perinuclear clusters in human dopaminergic neurons, which localized at the Golgi apparatus. These TFEB clusters were more frequently observed and more severe in iLBD, sPD/DLB and GBA-PD/DLB compared to controls, particularly in pSer129 aSyn-positive neurons, but also in neurons lacking detectable aSyn accumulation. In aSyn-negative cells, cytoplasmic TFEB clusters were more frequently observed in GBA-PD/DLB and iLBD patients, and correlated with reduced GBA enzymatic activity as well as increased Braak LB stage. Altered TFEB distribution was accompanied by a reduction in overall mRNA expression levels of selected TFEB-regulated genes, indicating a possible early dysfunction of lysosomal regulation. Overall, we observed cytoplasmic TFEB retention and accumulation at the Golgi in cells without apparent pSer129 aSyn accumulation in iLBD and PD/DLB patients. This suggests potential TFEB impairment at the early stages of cellular disease and underscores TFEB as a promising therapeutic target for synucleinopathies.


Asunto(s)
Enfermedad por Cuerpos de Lewy , Humanos , alfa-Sinucleína/metabolismo , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Encéfalo/patología , Neuronas Dopaminérgicas/metabolismo , Cuerpos de Lewy/patología , Enfermedad por Cuerpos de Lewy/patología
3.
Nat Commun ; 14(1): 2057, 2023 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-37045813

RESUMEN

Mutations in glucocerebrosidase cause the lysosomal storage disorder Gaucher's disease and are the most common risk factor for Parkinson's disease. Therapies to restore the enzyme's function in the brain hold great promise for treating the neurological implications. Thus, we developed blood-brain barrier penetrant therapeutic molecules by fusing transferrin receptor-binding moieties to ß-glucocerebrosidase (referred to as GCase-BS). We demonstrate that these fusion proteins show significantly increased uptake and lysosomal efficiency compared to the enzyme alone. In a cellular disease model, GCase-BS rapidly rescues the lysosomal proteome and lipid accumulations beyond known substrates. In a mouse disease model, intravenous injection of GCase-BS leads to a sustained reduction of glucosylsphingosine and can lower neurofilament-light chain plasma levels. Collectively, these findings demonstrate the potential of GCase-BS for treating GBA1-associated lysosomal dysfunction, provide insight into candidate biomarkers, and may ultimately open a promising treatment paradigm for lysosomal storage diseases extending beyond the central nervous system.


Asunto(s)
Enfermedad de Gaucher , Enfermedad de Parkinson , Animales , Ratones , Enfermedad de Gaucher/genética , Glucosilceramidasa/genética , Glucosilceramidasa/metabolismo , Encéfalo/metabolismo , Neuronas/metabolismo , Enfermedad de Parkinson/metabolismo , Lisosomas/metabolismo , Mutación , alfa-Sinucleína/metabolismo
4.
J Cell Physiol ; 237(9): 3578-3586, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35678366

RESUMEN

The insulin signaling pathway controls cell growth and metabolism, thus its deregulation is associated with both cancer and diabetes. Phosphatidylinositol 3-kinase (PI3K) contributes to the cascade of phosphorylation events occurring in the insulin pathway by activating the protein kinase B (PKB/AKT), which phosphorylates several substrates, including those involved in glucose uptake and storage. PI3K inactivating mutations are associated with insulin resistance while activating mutations are identified in human cancers. Here we show that RNAi-induced depletion of the Drosophila PI3K catalytic subunit (Dp110) results in diabetic phenotypes such as hyperglycemia, body size reduction, and decreased glycogen content. Interestingly, we found that hyperglycemia produces chromosome aberrations (CABs) triggered by the accumulation of advanced glycation end-products and reactive oxygen species. Rearing PI3KRNAi flies in a medium supplemented with pyridoxal 5'-phosphate (PLP; the catalytically active form of vitamin B6) rescues DNA damage while, in contrast, treating PI3KRNAi larvae with the PLP inhibitor 4-deoxypyridoxine strongly enhances CAB frequency. Interestingly, PLP supplementation rescues also diabetic phenotypes. Taken together, our results provide a strong link between impaired PI3K activity and genomic instability, a crucial relationship that needs to be monitored not only in diabetes due to impaired insulin signaling but also in cancer therapies based on PI3K inhibitors. In addition, our findings confirm the notion that vitamin B6 is a good natural remedy to counteract insulin resistance and its complications.


Asunto(s)
Daño del ADN , Fosfatidilinositol 3-Quinasa , Vitamina B 6 , Animales , Daño del ADN/efectos de los fármacos , Modelos Animales de Enfermedad , Drosophila/efectos de los fármacos , Drosophila/metabolismo , Glucosa/farmacología , Humanos , Hiperglucemia , Insulina/metabolismo , Resistencia a la Insulina , Fosfatidilinositol 3-Quinasa/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fosfato de Piridoxal/farmacología , Vitamina B 6/farmacología
5.
Int J Mol Sci ; 22(21)2021 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-34769443

RESUMEN

Several variants of the enzyme pyridox(am)ine 5'-phosphate oxidase (PNPO), responsible for a rare form of vitamin B6-dependent neonatal epileptic encephalopathy known as PNPO deficiency (PNPOD), have been reported. However, only a few of them have been characterised with respect to their structural and functional properties, despite the fact that the knowledge of how variants affect the enzyme may clarify the disease mechanism and improve treatment. Here, we report the characterisation of the catalytic, allosteric and structural properties of recombinantly expressed D33V, R161C, P213S, and E50K variants, among which D33V (present in approximately 10% of affected patients) is one of the more common variants responsible for PNPOD. The D33V and E50K variants have only mildly altered catalytic properties. In particular, the E50K variant, given that it has been found on the same chromosome with other known pathogenic variants, may be considered non-pathogenic. The P213S variant has lower thermal stability and reduced capability to bind the FMN cofactor. The variant involving Arg161 (R161C) largely decreases the affinity for the pyridoxine 5'-phosphate substrate and completely abolishes the allosteric feedback inhibition exerted by the pyridoxal 5'-phosphate product.


Asunto(s)
Encefalopatías Metabólicas/genética , Epilepsia/genética , Hipoxia-Isquemia Encefálica/genética , Mutación , Fosfato de Piridoxal/análogos & derivados , Piridoxaminafosfato Oxidasa/deficiencia , Piridoxaminafosfato Oxidasa/genética , Convulsiones/genética , Vitamina B 6/metabolismo , Encefalopatías Metabólicas/metabolismo , Encefalopatías Metabólicas/patología , Epilepsia/metabolismo , Epilepsia/patología , Humanos , Hipoxia-Isquemia Encefálica/metabolismo , Hipoxia-Isquemia Encefálica/patología , Recién Nacido , Enfermedades Metabólicas/etiología , Enfermedades Metabólicas/metabolismo , Enfermedades Metabólicas/patología , Fosfato de Piridoxal/metabolismo , Piridoxaminafosfato Oxidasa/metabolismo , Convulsiones/metabolismo , Convulsiones/patología , Relación Estructura-Actividad
6.
Pharmaceuticals (Basel) ; 14(8)2021 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-34451834

RESUMEN

The disturbed metabolism of vitamins B1 or B6, which are essential for neurotransmitters homeostasis, may cause seizures. Our study aims at revealing therapeutic potential of vitamins B1 and B6 by estimating the short- and long-term effects of their combined administration with the seizure inductor pentylenetetrazole (PTZ). The PTZ dose dependence of a seizure and its parameters according to modified Racine's scale, along with delayed physiological and biochemical consequences the next day after the seizure are assessed regarding sexual dimorphism in epilepsy. PTZ sensitivity is stronger in the female than the male rats. The next day after a seizure, sex differences in behavior and brain biochemistry arise. The induced sex differences in anxiety and locomotor activity correspond to the disappearance of sex differences in the brain aspartate and alanine, with appearance of those in glutamate and glutamine. PTZ decreases the brain malate dehydrogenase activity and urea in the males and the phenylalanine in the females. The administration of vitamins B1 and B6 24 h before PTZ delays a seizure in female rats only. This desensitization is not observed at short intervals (0.5-2 h) between the administration of the vitamins and PTZ. With the increasing interval, the pyridoxal kinase (PLK) activity in the female brain decreases, suggesting that the PLK downregulation by vitamins contributes to the desensitization. The delayed effects of vitamins and/or PTZ are mostly sex-specific and interacting. Our findings on the sex differences in sensitivity to epileptogenic factors, action of vitamins B1/B6 and associated biochemical events have medical implications.

7.
Life (Basel) ; 11(5)2021 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-34068845

RESUMEN

Cysteine sulfinic acid decarboxylase catalyzes the last step of taurine biosynthesis in mammals, and belongs to the fold type I superfamily of pyridoxal-5'-phosphate (PLP)-dependent enzymes. Taurine (2-aminoethanesulfonic acid) is the most abundant free amino acid in animal tissues; it is highly present in liver, kidney, muscle, and brain, and plays numerous biological and physiological roles. Despite the importance of taurine in human health, human cysteine sulfinic acid decarboxylase has been poorly characterized at the biochemical level, although its three-dimensional structure has been solved. In the present work, we have recombinantly expressed and purified human cysteine sulfinic acid decarboxylase, and applied a simple spectroscopic direct method based on circular dichroism to measure its enzymatic activity. This method gives a significant advantage in terms of simplicity and reduction of execution time with respect to previously used assays, and will facilitate future studies on the catalytic mechanism of the enzyme. We determined the kinetic constants using L-cysteine sulfinic acid as substrate, and also showed that human cysteine sulfinic acid decarboxylase is capable to catalyze the decarboxylation-besides its natural substrates L-cysteine sulfinic acid and L-cysteic acid-of L-aspartate and L-glutamate, although with much lower efficiency.

8.
EcoSal Plus ; 9(2)2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33787481

RESUMEN

Vitamin B6 is an ensemble of six interconvertible vitamers: pyridoxine (PN), pyridoxamine (PM), pyridoxal (PL), and their 5'-phosphate derivatives, PNP, PMP, and PLP. Pyridoxal 5'-phosphate is a coenzyme in a variety of enzyme reactions concerning transformations of amino and amino acid compounds. This review summarizes all known and putative PLP-binding proteins found in the Escherichia coli MG1655 proteome. PLP can have toxic effects since it contains a very reactive aldehyde group at its 4' position that easily forms aldimines with primary and secondary amines and reacts with thiols. Most PLP is bound either to the enzymes that use it as a cofactor or to PLP carrier proteins, protected from the cellular environment but at the same time readily transferable to PLP-dependent apoenzymes. E. coli and its relatives synthesize PLP through the seven-step deoxyxylulose-5-phosphate (DXP)-dependent pathway. Other bacteria synthesize PLP in a single step, through a so-called DXP-independent pathway. Although the DXP-dependent pathway was the first to be revealed, the discovery of the widespread DXP-independent pathway determined a decline of interest in E. coli vitamin B6 metabolism. In E. coli, as in most organisms, PLP can also be obtained from PL, PN, and PM, imported from the environment or recycled from protein turnover, via a salvage pathway. Our review deals with all aspects of vitamin B6 metabolism in E. coli, from transcriptional to posttranslational regulation. A critical interpretation of results is presented, in particular, concerning the most obscure aspects of PLP homeostasis and delivery to PLP-dependent enzymes.


Asunto(s)
Piridoxina , Vitamina B 6 , Escherichia coli/genética , Fosfato de Piridoxal , Vitaminas
9.
Pol J Vet Sci ; 23(3): 465-468, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33006862

RESUMEN

Staphylococcus pseudintermedius (SP) and methicillin-resistant SP (MRSP) is one of the most important veterinary pathogens in the dog. Herein, from a total of 126 S. pseudintermediusstrains, 23 MRSP (18%) were identified. Multi-Locus Sequence Typing (MLST) revealed that most of MRSP strains belonged to ST71 (26%), which have been already reported in Italy and other countries. Interestingly, nine new sequence types (39%), from 1053 up to 1061, were described for the first time. Moreover, the isolated MRSP strains showed relevant antibiotic resistance profiles. This report highlights the circulation of new sequence types of MRSP in Italy and underlines the need of a global epidemiological surveillance to limit the increasing spread of multidrug-resistant MRSPstrains worldwide, since they may represent a considerable concern for dog's health.


Asunto(s)
Enfermedades de los Perros/microbiología , Resistencia a la Meticilina , Meticilina/farmacología , Otitis Externa/veterinaria , Infecciones Cutáneas Estafilocócicas/veterinaria , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Animales , Enfermedades de los Perros/epidemiología , Perros , Italia/epidemiología , Otitis Externa/epidemiología , Otitis Externa/microbiología , Piodermia/epidemiología , Piodermia/microbiología , Piodermia/veterinaria , Infecciones Cutáneas Estafilocócicas/epidemiología , Infecciones Cutáneas Estafilocócicas/microbiología
10.
Sci Rep ; 10(1): 13621, 2020 08 12.
Artículo en Inglés | MEDLINE | ID: mdl-32788630

RESUMEN

Defects of vitamin B6 metabolism are responsible for severe neurological disorders, such as pyridoxamine 5'-phosphate oxidase deficiency (PNPOD; OMIM: 610090), an autosomal recessive inborn error of metabolism that usually manifests with neonatal-onset severe seizures and subsequent encephalopathy. At present, 27 pathogenic mutations of the gene encoding human PNPO are known, 13 of which are homozygous missense mutations; however, only 3 of them have been characterised with respect to the molecular and functional properties of the variant enzyme forms. Moreover, studies on wild type and variant human PNPOs have so far largely ignored the regulation properties of this enzyme. Here, we present a detailed characterisation of the inhibition mechanism of PNPO by pyridoxal 5'-phosphate (PLP), the reaction product of the enzyme. Our study reveals that human PNPO has an allosteric PLP binding site that plays a crucial role in the enzyme regulation and therefore in the regulation of vitamin B6 metabolism in humans. Furthermore, we have produced, recombinantly expressed and characterised several PNPO pathogenic variants responsible for PNPOD (G118R, R141C, R225H, R116Q/R225H, and X262Q). Such replacements mainly affect the catalytic activity of PNPO and binding of the enzyme substrate and FMN cofactor, leaving the allosteric properties unaltered.


Asunto(s)
Encefalopatías Metabólicas/genética , Hipoxia-Isquemia Encefálica/genética , Fosfato de Piridoxal/metabolismo , Piridoxaminafosfato Oxidasa/química , Piridoxaminafosfato Oxidasa/deficiencia , Piridoxaminafosfato Oxidasa/metabolismo , Convulsiones/genética , Regulación Alostérica , Sitio Alostérico , Dominio Catalítico , Cristalografía por Rayos X , Mononucleótido de Flavina/metabolismo , Variación Genética , Humanos , Modelos Moleculares , Conformación Proteica , Piridoxaminafosfato Oxidasa/genética
11.
J Appl Microbiol ; 129(5): 1261-1271, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32445616

RESUMEN

AIMS: To conduct biological investigations and to evaluate the antimicrobial and antioxidant activities of the essential oils (EOs) extracted from Juniperus communis, J. scopulorum and J. horizontalis; to screen their mechanisms of action by conducting the cell membrane permeability assay (CMP); and to determine the possible cytotoxicity of the three EOs against human neuroblastoma cells (SH-SY5Y). METHODS AND RESULTS: The antifungal activity was tested against four phytopathogenic fungi (Monilinia fructicola, Aspergillus niger, Penicillium expansum and Botrytis cinerea). The antibacterial activity was evaluated against two Gram-positive (G+ve) (Bacillus megaterium and Clavibacter michiganensis) and three Gram-negative (G-ve) bacterial strains (Pseudomonas fluorescens, P. syringae pv. phaseolicola and Xanthomonas campestris). Results showed that the three tested EOs have antifungal activity against M. fructicola and P. expansum and effective antibacterial activity against P. syringae pv. phaseolicola and B. megaterium. Moreover, the three EOs were evaluated for their ability to inhibit the growth of SH-SY5Y cells with MTT assay. J. communis EO was the more effective with an IC50 of 53·7 µg ml-1 . The antioxidant capacity of the three EO did not differ as measured by the DPPH assay. CONCLUSIONS: The three tested juniper EOs showed promising antimicrobial and antioxidant activity and cytotoxic effects against human neuroblastoma cell line. SIGNIFICANCE AND IMPACT OF THE STUDY: The outfindings from this research showed promising antimicrobial effects of the three oils against the majority of the tested phytopathogens with a potential to utilize them as natural alternatives to synthetic drugs, the cause of global environmental problems, pathogen resistance and difficulty to control many post-harvest plant diseases.


Asunto(s)
Antiinfecciosos/farmacología , Antioxidantes/farmacología , Juniperus/química , Aceites Volátiles/farmacología , Aceites de Plantas/farmacología , Bacterias/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Hongos/efectos de los fármacos , Humanos , Juniperus/clasificación , Pruebas de Sensibilidad Microbiana , Enfermedades de las Plantas/microbiología
12.
FEBS J ; 287(22): 4952-4970, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32147931

RESUMEN

Bacillus subtilis is able to use γ-aminobutyric acid (GABA) found in the soil as carbon and nitrogen source, through the action of GABA aminotransferase (GabT) and succinic semialdehyde dehydrogenase (GabD). GABA acts as molecular effector in the transcriptional activation of the gabTD operon by GabR. GabR is the most studied member of the MocR family of prokaryotic pyridoxal 5'-phosphate (PLP)-dependent transcriptional regulators, yet crucial aspects of its mechanism of action are unknown. GabR binds to the gabTD promoter, but transcription is activated only when GABA is present. Here, we demonstrated, in contrast with what had been previously proposed, that three repeated nucleotide sequences in the promoter region, two direct repeats and one inverted repeat, are specifically recognized by GabR. We carried out in vitro and in vivo experiments using mutant forms of the gabTD promoter. Our results showed that GABA activates transcription by changing the modality of interaction between GabR and the recognized sequence repeats. A hypothetical model is proposed in which GabR exists in two alternative conformations that, respectively, prevent or promote transcription. According to this model, in the absence of GABA, GabR binds to DNA interacting with all three sequence repeats, overlapping the RNA polymerase binding site and therefore preventing transcription activation. On the other hand, when GABA binds to GabR, a conformational change of the protein leads to the release of the interaction with the inverted repeat, allowing transcription initiation by RNA polymerase.


Asunto(s)
4-Aminobutirato Transaminasa/genética , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Regiones Promotoras Genéticas/genética , Secuencias Repetitivas de Ácidos Nucleicos/genética , Succionato-Semialdehído Deshidrogenasa/genética , Ácido gamma-Aminobutírico/farmacología , 4-Aminobutirato Transaminasa/metabolismo , Bacillus subtilis/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Mutación , Operón/genética , Unión Proteica/efectos de los fármacos , Homología de Secuencia de Ácido Nucleico , Succionato-Semialdehído Deshidrogenasa/metabolismo , Activación Transcripcional/efectos de los fármacos , Ácido gamma-Aminobutírico/metabolismo
15.
Neuron ; 104(5): 869-884.e11, 2019 12 04.
Artículo en Inglés | MEDLINE | ID: mdl-31648898

RESUMEN

Age-related neurodegenerative disorders are characterized by a slow, persistent accumulation of aggregated proteins. Although cells can elicit physiological responses to enhance cellular clearance and counteract accumulation, it is unclear how pathogenic proteins evade this process in disease. We find that Parkinson's disease α-synuclein perturbs the physiological response to lysosomal stress by impeding the SNARE protein ykt6. Cytosolic ykt6 is normally autoinhibited by a unique farnesyl-mediated regulatory mechanism; however, during lysosomal stress, it activates and redistributes into membranes to preferentially promote hydrolase trafficking and enhance cellular clearance. α-Synuclein aberrantly binds and deactivates ykt6 in patient-derived neurons, thereby disabling the lysosomal stress response and facilitating protein accumulation. Activating ykt6 by small-molecule farnesyltransferase inhibitors restores lysosomal activity and reduces α-synuclein in patient-derived neurons and mice. Our findings indicate that α-synuclein creates a permissive environment for aggregate persistence by inhibiting regulated cellular clearance and provide a therapeutic strategy to restore protein homeostasis by harnessing SNARE activity.


Asunto(s)
Lisosomas/metabolismo , Neuronas/metabolismo , Enfermedad de Parkinson/metabolismo , Proteínas R-SNARE/metabolismo , alfa-Sinucleína/metabolismo , Animales , Células Cultivadas , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Transporte de Proteínas/fisiología , Estrés Fisiológico/fisiología
16.
Ultrason Sonochem ; 55: 1-7, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31084783

RESUMEN

We report the sonochemical synthesis of hydrogenated metallic microparticles through room-temperature ultrasonic irradiation of aqueous metallic slurries. The role of saturating gases and of reduction-oxidation mechanism on promoting the hydride formation is investigated. The method is then applied to study the synthesis of different metallic hydrides (Mn, Ti) and the hydrogenation of La(Fe,Mn,Si)13, an intermetallic compound with magnetocaloric properties used in magnetic refrigeration applications. The samples were characterized by X-ray diffraction to identify the presence of hydrogenated phases, by differential scanning calorimetry to evaluate hydrogen release and temperature stability of the hydrides and by electron microscopy to identify morphological modifications induced by acoustic cavitation. The hydrogenation of metallic microparticles and intermetallic compounds is reported for the first time by means of this experimental technique which could represent a new tool for fast and cheap hydrogenation of materials for different technological applications, such as hydrogen storage and magnetic refrigeration.

17.
Front Mol Biosci ; 6: 6, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30863751

RESUMEN

Plants, algae and most bacteria synthesize 5-aminolevulinic acid (ALA), the universal precursor of tetrapyrroles such as heme, chlorophyll and coenzyme B12, by a two-step transformation involving the NADPH-dependent glutamyl-tRNA reductase (HemA), which reduces tRNA-bound glutamate to glutamate-1-semialdehyde (GSA), and the pyridoxamine 5'-phosphate-dependent glutamate-1-semialdehyde-2,1-aminomutase (HemL), responsible for the isomerization of GSA into ALA. Since GSA is a very unstable compound at pH values around neutrality, the formation of a HemA-HemL complex has been proposed to occur, allowing for direct channeling of this intermediate from HemA to HemL. Experimental evidence of the formation of this complex has been obtained with the enzymes from Escherichia coli and Chlamydomonas reinhardtii. However, its isolation has never been attained, probably because HemA is degraded when intracellular heme accumulates. In this work, we devised a co-expression and co-purification strategy of HemA and HemL from Acinetobacter baumannii, which allowed the isolation of the HemA-HemL complex. Our results indicate that HemA is stabilized when co-expressed with HemL. The addition of citrate throughout the expression and purification procedure further promotes the formation of the HemA-HemL complex, which can be isolated in fair amount for functional and structural studies. This work lays the bases for a rational design of HemA-HemA inhibitors to be developed as antibacterial agents against A. baumannii, a multidrug resistant opportunistic pathogen responsible for a broad range of severe nosocomial infections.

18.
Plant Biol (Stuttg) ; 21(3): 507-514, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-29779248

RESUMEN

This work aims to study seeds of the endemic species Astragalus aquilanus from four different populations of central Italy. We investigated seed morpho-colorimetric features (shape and size) and chemical differences (through infrared spectroscopy) among populations and between dark and light seeds. Seed morpho-colorimetric quantitative variables, describing shape, size and colour traits, were measured using image analysis techniques. Fourier transform infrared (FT-IR) spectroscopy was used to attempt seed chemical characterisation. The measured data were analysed by step-wise linear discriminant analysis (LDA). Moreover, we analysed the correlation between the four most important traits and six climatic variables extracted from WorldClim 2.0. The LDA on seeds traits shows clear differentiation of the four populations, which can be attributed to different chemical composition, as confirmed by Wilk's lambda test (P < 0.001). A strong correlation between morphometric traits and temperature (annual mean temperature, mean temperature of the warmest and coolest quarter), colorimetric traits and precipitation (annual precipitation, precipitation of wettest and driest quarter) was observed. The characterisation of A. aquilanus seeds shows large intraspecific plasticity both in morpho-colorimetric and chemical composition. These results confirm the strong relationship between the type of seed produced and the climatic variables.


Asunto(s)
Fabaceae/fisiología , Semillas/fisiología , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura
19.
Biochemistry ; 57(51): 6984-6996, 2018 12 26.
Artículo en Inglés | MEDLINE | ID: mdl-30500180

RESUMEN

Serine hydroxymethyltransferase (SHMT) catalyzes the reversible conversion of l-serine and tetrahydrofolate into glycine and 5,10-methylenetetrahydrofolate. This enzyme, which plays a pivotal role in one-carbon metabolism, is involved in cancer metabolic reprogramming and is a recognized target of chemotherapy intervention. In humans, two isoforms of the enzyme exist, which are commonly termed cytosolic SHMT1 and mitochondrial SHMT2. Considerable attention has been paid to the structural, mechanistic, and metabolic features of these isozymes. On the other hand, a detailed comparison of their catalytic and regulatory properties is missing, although this aspect seems to be considerably important, considering that SHMT1 and SHMT2 reside in different cellular compartments, where they play distinct roles in folate metabolism. Here we performed a full kinetic characterization of the serine hydroxymethyltransferase reaction catalyzed by SHMT1 and SHMT2, with a focus on pH dependence and substrate inhibition. Our investigation, which allowed the determination of all kinetic parameters of serine hydroxymethyltransferase forward and backward reactions, uncovered a previously unobserved substrate inhibition by l-serine and highlighted several interesting differences between SHMT1 and SHMT2. In particular, SHMT2 maintains a pronounced tetrahydrofolate substrate inhibition even at the alkaline pH characteristic of the mitochondrial matrix, whereas with SHMT1 this is almost abolished. At this pH, SHMT2 also shows a catalytic efficiency that is much higher than that of SHMT1. These observations suggest that such different properties represent an adaptation of the isoforms to the respective cellular environments and that substrate inhibition may be a form of regulation.


Asunto(s)
Glicina Hidroximetiltransferasa/metabolismo , Citosol/enzimología , Glicina/metabolismo , Glicina Hidroximetiltransferasa/antagonistas & inhibidores , Glicina Hidroximetiltransferasa/química , Humanos , Concentración de Iones de Hidrógeno , Isoenzimas/antagonistas & inhibidores , Isoenzimas/química , Isoenzimas/metabolismo , Cinética , Mitocondrias/enzimología , Modelos Biológicos , Serina/metabolismo , Especificidad por Sustrato , Tetrahidrofolatos/metabolismo
20.
Pol J Vet Sci ; 21(3): 639-642, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30468352

RESUMEN

In the present study on Bubalus bubalis of the Campania Region (Italy) the serum levels of derivatives of reactive oxygen metabolites (d-ROMs), anti-ROM and oxidative stress index (Osi) were evaluated. These data were then related to the seropositive status of the animals against alpha-herpesviruses, precisely Bubaline herpesvirus 1 (BuHV-1) and Bovine herpesvirus 1 (BoHV-1). Clinically healthy Mediterranean buffaloes were selected for this study. The serum samples of these animals were taken, and d-ROMs, anti-ROM and Osi were measured using commercially available tests. The preliminary data demonstrated that animals seropositive to both BuHV-1 and BoHV-1 present more oxidative stress than seronegative animals, as revealed by a significant increase in d-ROMs. Our results provide, for the first time, insight into the reac- tive oxygen species (ROS) modulation induced by the herpesvirus in Bubalus bubalis.


Asunto(s)
Alphaherpesvirinae/inmunología , Búfalos/sangre , Infecciones por Herpesviridae/veterinaria , Animales , Infecciones por Herpesviridae/sangre , Infecciones por Herpesviridae/inmunología , Infecciones por Herpesviridae/metabolismo , Especies Reactivas de Oxígeno , Estudios Seroepidemiológicos
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