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1.
Int J Mol Sci ; 25(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38474294

RESUMO

Platinum compounds are very active in first-line treatments of ovarian carcinoma. In fact, high rates of complete remission are achieved, but most patients eventually relapse with resistant disease. Many mechanisms underlying the platinum-resistant phenotype have been reported. However, there are no data in the same isogenic cell system proficient and deficient in homologous recombination (HR) on platinum-acquired resistance that might unequivocally clarify the most important mechanism associated with resistance. We generated and characterized cisplatin (DDP)-resistant murine ovarian ID8 cell lines in a HR-deficient and -proficient background. Specific upregulation of the NER pathway in the HR-proficient and -resistant cells and partial restoration of HR in Brca1-/--resistant cells were found. Combinations of different inhibitors of the DNA damage response pathways with cisplatin were strongly active in both resistant and parental cells. The data from the ID8 isogenic system are in line with current experimental and clinical evidence and strongly suggest that platinum resistance develops in different ways depending on the cell DNA repair status (i.e., HR-proficient or HR-deficient), and the upregulation and/or restoration of repair pathways are major determinants of DDP resistance.


Assuntos
Cisplatino , Neoplasias Ovarianas , Humanos , Feminino , Animais , Camundongos , Cisplatino/farmacologia , Platina , Recidiva Local de Neoplasia , Neoplasias Ovarianas/metabolismo , Recombinação Homóloga , Resistencia a Medicamentos Antineoplásicos , Linhagem Celular Tumoral
2.
J Biol Chem ; 296: 100664, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33865852

RESUMO

The formation of neurofibrillary tangles and amyloid plaques accompanies the progression of Alzheimer's disease. Tangles are made of fibrillar aggregates formed by the microtubule-associated protein tau, whereas plaques comprise fibrillar forms of amyloid-beta (Aß). Both form toxic oligomers during aggregation and are thought to interact synergistically to each promote the accumulation of the other. Recent in vitro studies have suggested that the monomeric nonphosphorylated full-length tau protein hinders the aggregation of Aß1-40 peptide, but whether the same is true for the more aggregation-prone Aß1-42 was not determined. We used in vitro and in vivo techniques to explore this question. We have monitored the aggregation kinetics of Aß1-42 by thioflavine T fluorescence in the presence or the absence of different concentrations of nonphosphorylated tau. We observed that elongation of Aß1-42 fibrils was inhibited by tau in a dose-dependent manner. Interestingly, the fibrils were structurally different in the presence of tau but did not incorporate tau. Surface plasmon resonance indicated that tau monomers bound to Aß1-42 oligomers (but not monomers) and hindered their interaction with the anti-Aß antibody 4G8, suggesting that tau binds to the hydrophobic central core of Aß recognized by 4G8. Tau monomers also antagonized the toxic effects of Aß oligomers in Caenorhabditis elegans. This suggests that nonphosphorylated tau might have a neuroprotective effect by binding Aß1-42 oligomers formed during the aggregation and shielding their hydrophobic patches.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Amiloide/antagonistas & inibidores , Caenorhabditis elegans/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Fármacos Neuroprotetores/farmacologia , Fragmentos de Peptídeos/antagonistas & inibidores , Proteínas tau/farmacologia , Peptídeos beta-Amiloides/toxicidade , Animais , Caenorhabditis elegans/efeitos dos fármacos , Humanos , Cinética , Larva/efeitos dos fármacos , Fragmentos de Peptídeos/toxicidade
3.
J Biol Chem ; 296: 100490, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33662396

RESUMO

Fatal familial insomnia (FFI), genetic Creutzfeldt-Jakob disease (gCJD), and Gerstmann-Sträussler-Scheinker (GSS) syndrome are neurodegenerative disorders linked to prion protein (PrP) mutations. The pathogenic mechanisms are not known, but increasing evidence points to mutant PrP misfolding and retention in the secretory pathway. We previously found that the D178N/M129 mutation associated with FFI accumulates in the Golgi of neuronal cells, impairing post-Golgi trafficking. In this study we further characterized the trafficking defect induced by the FFI mutation and tested the 178N/V129 variant linked to gCJD and a nine-octapeptide repeat insertion associated with GSS. We used transfected HeLa cells, embryonic fibroblasts and primary neurons from transgenic mice, and fibroblasts from carriers of the FFI mutation. In all these cell types, the mutant PrPs showed abnormal intracellular localizations, accumulating in the endoplasmic reticulum (ER) and Golgi. To test the efficiency of the membrane trafficking system, we monitored the intracellular transport of the temperature-sensitive vesicular stomatite virus glycoprotein (VSV-G), a well-established cargo reporter, and of endogenous procollagen I (PC-I). We observed marked alterations in secretory trafficking, with VSV-G accumulating mainly in the Golgi complex and PC-I in the ER and Golgi. A redacted version of mutant PrP with reduced propensity to misfold did not impair VSV-G trafficking, nor did artificial ER or Golgi retention of wild-type PrP; this indicates that both misfolding and intracellular retention were required to induce the transport defect. Pharmacological activation of Src family kinase (SFK) improved intracellular transport, suggesting that mutant PrP impairs secretory trafficking through corruption of SFK-mediated signaling.


Assuntos
Mutação , Proteínas Priônicas/metabolismo , Quinases da Família src/metabolismo , Animais , Células Cultivadas , Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Modelos Animais de Doenças , Retículo Endoplasmático/metabolismo , Ativação Enzimática , Doença de Gerstmann-Straussler-Scheinker/genética , Doença de Gerstmann-Straussler-Scheinker/metabolismo , Doença de Gerstmann-Straussler-Scheinker/patologia , Complexo de Golgi/metabolismo , Humanos , Insônia Familiar Fatal/genética , Insônia Familiar Fatal/metabolismo , Insônia Familiar Fatal/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Proteínas Priônicas/genética , Dobramento de Proteína , Via Secretória , Quinases da Família src/química
4.
J Am Soc Nephrol ; 32(5): 1114-1130, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33722931

RESUMO

BACKGROUND: Podocyte dysfunction and loss are major determinants in the development of proteinuria. FSGS is one of the most common causes of proteinuria, but the mechanisms leading to podocyte injury or conferring protection against FSGS remain poorly understood. The cytosolic protein M-Sec has been involved in the formation of tunneling nanotubes (TNTs), membrane channels that transiently connect cells and allow intercellular organelle transfer. Whether podocytes express M-Sec is unknown and the potential relevance of the M-Sec-TNT system in FSGS has not been explored. METHODS: We studied the role of the M-Sec-TNT system in cultured podocytes exposed to Adriamycin and in BALB/c M-Sec knockout mice. We also assessed M-Sec expression in both kidney biopsies from patients with FSGS and in experimental FSGS (Adriamycin-induced nephropathy). RESULTS: Podocytes can form TNTs in a M-Sec-dependent manner. Consistent with the notion that the M-Sec-TNT system is cytoprotective, podocytes overexpressed M-Sec in both human and experimental FSGS. Moreover, M-Sec deletion resulted in podocyte injury, with mitochondrial abnormalities and development of progressive FSGS. In vitro, M-Sec deletion abolished TNT-mediated mitochondria transfer between podocytes and altered mitochondrial bioenergetics. Re-expression of M-Sec reestablishes TNT formation and mitochondria exchange, rescued mitochondrial function, and partially reverted podocyte injury. CONCLUSIONS: These findings indicate that the M-Sec-TNT system plays an important protective role in the glomeruli by rescuing podocytes via mitochondrial horizontal transfer. M-Sec may represent a promising therapeutic target in FSGS, and evidence that podocytes can be rescued via TNT-mediated horizontal transfer may open new avenues of research.


Assuntos
Glomerulosclerose Segmentar e Focal/metabolismo , Podócitos/metabolismo , Fatores de Necrose Tumoral/metabolismo , Idoso , Animais , Técnicas de Cultura de Células , Modelos Animais de Doenças , Doxorrubicina , Feminino , Glomerulosclerose Segmentar e Focal/etiologia , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Nanotubos , Podócitos/patologia
5.
Clin Chem Lab Med ; 59(11): 1832-1843, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34225393

RESUMO

OBJECTIVES: The search in the urinary sediment (U-sed) of fat particles with peculiar morphology is a simple and inexpensive tool for the diagnosis of Fabry disease (FD) nephropathy. In this study we investigated the morphology of a high number of such fat particles with the aim to obtain a morphological classification to be used for their identification. METHODS: Study of the morphology of fat particles in the U-sed of a cohort of FD patients using: bright field plus phase contrast microscopy (BF + PC), polarized light microscopy (POL), and transmission electron microscopy (TEM). Comparison of these results with those obtained for the fat particles seen in the U-sed of a control group (CG) of patients with non-FD glomerulopathies. RESULTS: FD: 18 U-sed from six patients (three samples/patient) were prospectively investigated and 506 fat particles identified. With BF + PC, these were classified in eight morphological categories (seven of which were confirmed by TEM), and with POL in 10 others. CG: eight U-sed from eight patients were investigated and 281 fat particles identified. These fell into four BF + PC morphological categories and into eight POL categories. While some categories were significantly more frequent in FD others were more frequent in the CG. CONCLUSIONS: Our study demonstrates that 1. The morphology of fat particles found in the U-sed of FD patients is much wider and complex than that described so far 2. Several significant differences exist in the morphology of such fat particles between FD and CG patients.


Assuntos
Doença de Fabry , Nefropatias , Doença de Fabry/diagnóstico , Humanos , Microscopia de Contraste de Fase
6.
Part Fibre Toxicol ; 18(1): 23, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34134756

RESUMO

BACKGROUND: Widespread use of silver in its different forms raises concerns about potential adverse effects after ingestion, the main exposure route for humans. The aim of this study was to investigate in CD-1 (ICR) male mice the tissue distribution and in vivo effects of 4-week oral exposure to 0.25 and 1 mg Ag/kg bw 10 nm citrate coated silver nanoparticles (AgNPs) and 1 mg Ag/kg bw silver acetate (AgAc) at the end of treatment (EoT) and after 4 weeks of recovery. RESULTS: There were no treatment-related clinical signs and mortality, and no significant effects on body and organ weights at the EoT and after recovery. Treatment-related changes in hematology and clinical chemistry were found after recovery, the most relevant being a dose-dependent lymphopenia and increased triglycerides in AgNP-treated mice, and increased levels of urea in all treated groups, associated with decreased albumin only in AgAc-treated mice. At the EoT the highest silver concentration determined by Triple Quadrupole ICP-MS analysis was found in the brain, followed by testis, liver, and spleen; much lower concentrations were present in the small intestine and kidney. Tissue silver concentrations were slightly higher after exposure to AgAc than AgNPs and dose dependent for AgNPs. After recovery silver was still present in the brain and testis, highlighting slow elimination. No histopathological changes and absence of silver staining by autometallography were observed in the organs of treated mice. At the EoT GFAP (astrocytes) immunoreactivity was significantly increased in the hippocampus of AgNP-treated mice in a dose-dependent manner and Iba1 (microglial cells) immunoreactivity was significantly increased in the cortex of 1 mg/kg bw AgNP-treated mice. After recovery, a significant reduction of Iba1 was observed in the cortex of all treated groups. TEM analysis of the hippocampus revealed splitting of basement membrane of the capillaries and swelling of astrocytic perivascular end-feet in 1 mg/kg bw AgNP- and AgAc-treated mice at the EoT. CONCLUSIONS: Our study revealed accumulation and slow clearance of silver in the brain after oral administration of 10 nm AgNPs and AgAc at low doses in mice, associated with effects on glial cells and ultrastructural alterations of the Blood-Brain Barrier.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Administração Oral , Animais , Encéfalo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Distribuição Tecidual
7.
Hum Mol Genet ; 27(14): 2477-2489, 2018 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-29718201

RESUMO

Marinesco-Sjögren syndrome (MSS) is a rare, early onset, autosomal recessive multisystem disorder characterized by cerebellar ataxia, cataracts and myopathy. Most MSS cases are caused by loss-of-function mutations in the gene encoding SIL1, a nucleotide exchange factor for the molecular chaperone BiP which is essential for correct protein folding in the endoplasmic reticulum. Woozy mice carrying a spontaneous Sil1 mutation recapitulate key pathological features of MSS, including cerebellar atrophy with degeneration of Purkinje cells and progressive myopathy. Because the PERK branch of the unfolded protein response is activated in degenerating neurons of woozy mice, and inhibiting PERK-mediated translational attenuation has shown protective effects in protein-misfolding neurodegenerative disease models, we tested the therapeutic efficacy of GSK2606414, a potent inhibitor of PERK. Mice were chronically treated with GSK2606414 starting from a presymptomatic stage, and the effects were evaluated on biochemical, histopathological and clinical readouts. GSK2606414 delayed Purkinje cell degeneration and the onset of motor deficits, prolonging the asymptomatic phase of the disease; it also reduced the skeletal muscle abnormalities and improved motor performance during the symptomatic phase. The protein but not the mRNA level of ORP150, a nucleotide exchange factor which can substitute for SIL1, was increased in the cerebellum of GSK2606414-treated woozy mice, suggesting that translational recovery promoted the synthesis of this alternative BiP co-factor. Targeting PERK signaling may have beneficial disease-modifying effects in carriers of SIL1 mutations.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/genética , Proteínas de Choque Térmico HSP70/genética , Degeneração Neural/genética , Degenerações Espinocerebelares/terapia , eIF-2 Quinase/genética , Adenina/administração & dosagem , Adenina/análogos & derivados , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/fisiopatologia , Modelos Animais de Doenças , Retículo Endoplasmático/genética , Retículo Endoplasmático/patologia , Heterozigoto , Humanos , Indóis/administração & dosagem , Mutação com Perda de Função/genética , Camundongos , Atividade Motora/fisiologia , Degeneração Neural/fisiopatologia , Dobramento de Proteína , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/patologia , Degenerações Espinocerebelares/genética , Degenerações Espinocerebelares/patologia , Resposta a Proteínas não Dobradas/genética
8.
Neuroimage ; 184: 490-495, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30240904

RESUMO

Alzheimer's disease (AD), the most common form of dementia, is a progressive neurodegenerative disorder associated with aberrant production of beta-amyloid (Aß) peptide depositing in brain as amyloid plaques. While animal models allow investigation of disease progression and therapeutic efficacy, technology to fully dissect the pathological mechanisms of this complex disease at cellular and vascular levels is lacking. X-ray phase contrast tomography (XPCT) is an advanced non-destructive 3D multi-scale direct imaging from the cell through to the whole brain, with exceptional spatial and contrast resolution. We exploit XPCT to simultaneously analyse disease-relevant vascular and neuronal networks in AD mouse brain, without sectioning and staining. The findings clearly show the different typologies and internal structures of Aß plaques, together with their interaction with patho/physiological cellular and neuro-vascular microenvironment. XPCT enables for the first time a detailed visualization of amyloid-angiopathy at capillary level, which is impossible to achieve with other approaches. XPCT emerges as added-value technology to explore AD mouse brain as a whole, preserving tissue chemistry and structure, enabling the comparison of physiological vs. pathological states at the level of crucial disease targets. In-vivo translation will permit to monitor emerging therapeutic approaches and possibly shed new light on pathological mechanisms of neurodegenerative diseases.


Assuntos
Doença de Alzheimer/patologia , Encéfalo/patologia , Imageamento Tridimensional/métodos , Neuroimagem/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Transgênicos
9.
J Neuroinflammation ; 16(1): 9, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30651101

RESUMO

BACKGROUND: Phagocytosis is a key function of myeloid cells and is highly involved in brain ischemic injury. It has been scarcely studied in vivo, thus preventing a deep knowledge of the processes occurring in the ischemic environment. Structured illumination microscopy (SIM) is a superresolution technique which helps study phagocytosis, a process involving the recruitment of vesicles sized below the resolution limits of standard confocal microscopy. METHODS: Mice underwent permanent occlusion of the middle cerebral artery and were sacrificed at 48 h or 7 days after insult. Immunofluorescence for CD11b, myeloid cell membrane marker, and CD68, lysosomal marker was done in the ischemic area. Images were acquired using a SIM system and verified with SIM check. Lysosomal distribution was measured in the ischemic area by the gray level co-occurrence matrix (GLCM). SIM dataset was compared with transmission electron microscopy images of macrophages in the ischemic tissue at the same time points. Cultured microglia were stimulated with LPS to uptake 100 nm fluorescent beads and imaged by time-lapse SIM. GLCM was used to analyze bead distribution over the cytoplasm. RESULTS: SIM images reached a resolution of 130 nm and passed the quality control diagnose, ruling out possible artifacts. After ischemia, GLCM applied to the CD68 images showed that myeloid cells at 48 h had higher angular second moment (ASM), inverse difference moment (IDM), and lower entropy than myeloid cells at 7 days indicating higher lysosomal clustering at 48 h. At this time point, lysosomal clustering was proximal (< 700 nm) to the cell membrane indicating active target internalization, while at 7 days, it was perinuclear, consistent with final stages of phagocytosis or autophagy. Electron microscopy images indicated a similar pattern of lysosomal distribution thus validating the SIM dataset. GLCM on time-lapse SIM from phagocytic microglia cultures revealed a temporal decrease in ASM and IDM and increase in entropy, as beads were uptaken, indicating that GLCM informs on the progression of phagocytosis. CONCLUSIONS: GLCM analysis on SIM dataset quantitatively described different phases of macrophage phagocytic behavior revealing the dynamics of lysosomal movements in the ischemic brain indicating initial active internalization vs. final digestion/autophagy.


Assuntos
Encéfalo/diagnóstico por imagem , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Infarto da Artéria Cerebral Média/patologia , Células Mieloides/fisiologia , Imagem Óptica/métodos , Fagocitose/fisiologia , Animais , Animais Recém-Nascidos , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Antígeno CD11b/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Lipopolissacarídeos/farmacologia , Lisossomos/patologia , Lisossomos/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Microglia/ultraestrutura , Microscopia Eletrônica de Transmissão , Células Mieloides/ultraestrutura , Medula Espinal/citologia , Fatores de Tempo
10.
Brain ; 141(9): 2685-2699, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30084913

RESUMO

Traumatic brain injury is a risk factor for subsequent neurodegenerative disease, including chronic traumatic encephalopathy, a tauopathy mostly associated with repetitive concussion and blast, but not well recognized as a consequence of severe traumatic brain injury. Here we show that a single severe brain trauma is associated with the emergence of widespread hyperphosphorylated tau pathology in a proportion of humans surviving late after injury. In parallel experimental studies, in a model of severe traumatic brain injury in wild-type mice, we found progressive and widespread tau pathology, replicating the findings in humans. Brain homogenates from these mice, when inoculated into the hippocampus and overlying cerebral cortex of naïve mice, induced widespread tau pathology, synaptic loss, and persistent memory deficits. These data provide evidence that experimental brain trauma induces a self-propagating tau pathology, which can be transmitted between mice, and call for future studies aimed at investigating the potential transmissibility of trauma associated tau pathology in humans.


Assuntos
Lesões Encefálicas Traumáticas/complicações , Tauopatias/etiologia , Tauopatias/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Animais , Encéfalo/patologia , Concussão Encefálica/patologia , Lesões Encefálicas Traumáticas/fisiopatologia , Córtex Cerebral/patologia , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Doenças Neurodegenerativas/patologia , Fosforilação , Proteínas tau/metabolismo , Proteínas tau/fisiologia
11.
Diabetologia ; 59(7): 1542-1548, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27121168

RESUMO

AIMS/HYPOTHESIS: We investigated the significance of microangiopathy in the development of foot ulcer, which is still disputed. METHODS: We assessed microangiopathy by histological analysis of the capillary ultrastructure using transmission electron microscopy and capillary density and arteriolar morphology in paraffin-embedded sections from the skin of type 2 diabetic patients: 30 neuroischaemic patients (Isc) revascularised with peripheral angioplasty and 30 neuropathic patients (Neu) with foot ulcer, compared with ten non-diabetic volunteers. RESULTS: In the diabetic patients, capillaries in the dermal papillary layer were fewer (-22.2%, 159 ± 43 vs 205 ± 52 mm(2) in non-diabetic volunteers, p < 0.01). They also showed detrimental remodelling, with a 2.2-fold increase in capillary basement membrane thickness (3.44 ± 1.19 vs 1.53 ± 0.34 µm in non-diabetic volunteers, p < 0.001) and a 57.7% decrease in lumen area (14.6 ± 11.1 vs 34.7 ± 27.5 µm(2), p < 0.001). No differences were observed between the diabetic Isc or Neu patients. Isc were more prone to develop arteriolar occlusion than Neu (16.8 ± 6.9% vs 6.7 ± 3.7%, respectively, p < 0.001). No patient had been amputated at 30 days and healing time was significantly longer in Isc (180 ± 120 vs 64 ± 50 days in Neu, p < 0.001). CONCLUSIONS/INTERPRETATION: Capillary microangiopathy is present in equal measure in neuroischaemic and neuropathic diabetic foot skin. The predominance of arteriolar occlusions with neuroischaemia indicated the existence of an additional 'small vessel disease' that did not affect an effective revascularisation and did not worsen the prognosis of major amputations but slowed the healing process of the neuroischaemic foot ulcer. TRIAL REGISTRATION: ClinicalTrials.gov NCT02610036.


Assuntos
Diabetes Mellitus Tipo 2/patologia , Angiopatias Diabéticas/patologia , Úlcera do Pé/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Microscopia Eletrônica de Transmissão , Pessoa de Meia-Idade , Estudos Prospectivos
12.
Blood ; 123(23): 3543-52, 2014 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24665135

RESUMO

Poor prognosis and limited therapeutic options characterize immunoglobulin light-chain (AL) amyloidosis with major heart involvement. Reliable experimental models are needed to study light-chain (LC)/heart interactions and to explore strategies for prevention of cardiac damage. We have exploited the nematode Caenorhabditis elegans as a novel tool, because its pharynx is evolutionarily related to the vertebrate heart. Our data demonstrate that the pharyngeal pumping of C elegans is significantly and selectively reduced by LCs from AL patients suffering from cardiomyopathy, but not by amyloid LCs with different organ tropism or nonamyloidogenic LCs from multiple myeloma. This functional alteration is dependent on the LC concentration and results in persistent pharyngeal dysfunction and in a significant reduction of the worms' lifespan. These manifestations are paralleled by an increase of mitochondrial reactive oxygen species and can be prevented by treatment with antioxidant agents. In conclusion, these data indicate that this nematode-based assay is a promising surrogate model for investigating the heart-specific toxicity of amyloidogenic LCs and for a rapid screening of new therapeutic strategies.


Assuntos
Amiloidose/diagnóstico , Caenorhabditis elegans , Cardiopatias/diagnóstico , Cadeias Leves de Imunoglobulina/imunologia , Adulto , Idoso , Amiloidose/imunologia , Animais , Bioensaio , Cardiotoxinas/isolamento & purificação , Cardiotoxinas/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Feminino , Cardiopatias/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/imunologia , Faringe/citologia , Faringe/efeitos dos fármacos , Faringe/fisiologia
13.
J Pathol ; 235(5): 731-44, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25408545

RESUMO

Idiopathic focal segmental glomerulosclerosis (FSGS) is a progressive and proteinuric kidney disease that starts with podocyte injury. Podocytes cover the external side of the glomerular capillary by a complex web of primary and secondary ramifications. Similar to dendritic spines of neuronal cells, podocyte processes rely on a dynamic actin-based cytoskeletal architecture to maintain shape and function. Brain-derived neurotrophic factor (BDNF) is a pleiotropic neurotrophin that binds to the tropomyosin-related kinase B receptor (TrkB) and has crucial roles in neuron maturation, survival, and activity. In neuronal cultures, exogenously added BDNF increases the number and size of dendritic spines. In animal models, BDNF administration is beneficial in both central and peripheral nervous system disorders. Here we show that BDNF has a TrkB-dependent trophic activity on podocyte cell processes; by affecting microRNA-134 and microRNA-132 signalling, BDNF up-regulates Limk1 translation and phosphorylation, and increases cofilin phosphorylation, which results in actin polymerization. Importantly, BDNF effectively repairs podocyte damage in vitro, and contrasts proteinuria and glomerular lesions in in vivo models of FSGS, opening a potential new perspective to the treatment of podocyte disorders.


Assuntos
Citoesqueleto de Actina/efeitos dos fármacos , Actinas/metabolismo , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Glomerulosclerose Segmentar e Focal/prevenção & controle , MicroRNAs/metabolismo , Podócitos/efeitos dos fármacos , Células 3T3 , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/patologia , Fatores de Despolimerização de Actina/metabolismo , Animais , Modelos Animais de Doenças , Regulação da Expressão Gênica , Glomerulosclerose Segmentar e Focal/induzido quimicamente , Glomerulosclerose Segmentar e Focal/genética , Glomerulosclerose Segmentar e Focal/metabolismo , Glomerulosclerose Segmentar e Focal/patologia , Larva/efeitos dos fármacos , Larva/metabolismo , Quinases Lim/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/genética , Fosforilação , Podócitos/metabolismo , Podócitos/patologia , Polimerização , Proteinúria/metabolismo , Proteinúria/prevenção & controle , Interferência de RNA , Receptor trkB/metabolismo , Proteínas Recombinantes/farmacologia , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Transfecção , Peixe-Zebra
14.
J Neurochem ; 135(1): 109-24, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25940956

RESUMO

Changes in the homeostasis of tumor necrosis factor α (TNFα) have been demonstrated in patients and experimental models of amyotrophic lateral sclerosis (ALS). However, the contribution of TNFα to the development of ALS is still debated. TNFα is expressed by glia and neurons and acts through the membrane receptors TNFR1 and TNFR2, which may have opposite effects in neurodegeneration. We investigated the role of TNFα and its receptors in the selective motor neuron death in ALS in vitro and in vivo. TNFR2 expressed by astrocytes and neurons, but not TNFR1, was implicated in motor neuron loss in primary SOD1-G93A co-cultures. Deleting TNFR2 from SOD1-G93A mice, there was partial but significant protection of spinal motor neurons, sciatic nerves, and tibialis muscles. However, no improvement of motor impairment or survival was observed. Since the sciatic nerves of SOD1-G93A/TNFR2-/- mice showed high phospho-TAR DNA-binding protein 43 (TDP-43) accumulation and low levels of acetyl-tubulin, two indices of axonal dysfunction, the lack of symptom improvement in these mice might be due to impaired function of rescued motor neurons. These results indicate the interaction between TNFR2 and membrane-bound TNFα as an innovative pathway involved in motor neuron death. Nevertheless, its inhibition is not sufficient to stop disease progression in ALS mice, underlining the complexity of this pathology. We show evidence of the involvement of neuronal and astroglial TNFR2 in the motor neuron degeneration in ALS. Both concur to cause motor neuron death in primary astrocyte/spinal neuron co-cultures. TNFR2 deletion partially protects motor neurons and sciatic nerves in SOD1-G93A mice but does not improve their symptoms and survival. However, TNFR2 could be a new target for multi-intervention therapies.


Assuntos
Esclerose Lateral Amiotrófica/metabolismo , Neurônios Motores/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Esclerose Lateral Amiotrófica/genética , Animais , Astrócitos/metabolismo , Axônios/metabolismo , Morte Celular/fisiologia , Células Cultivadas , Técnicas de Cocultura , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Camundongos , Neuroglia/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/deficiência
15.
Kidney Int ; 86(5): 979-90, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24827776

RESUMO

A functionally active endocannabinoid system is present within the kidney. The cannabinoid receptor type 2 (CB2) is expressed by both inflammatory cells and podocytes, and its activation has beneficial effects in experimental diabetic nephropathy. To further explore the role of CB2 in diabetic nephropathy, we studied renal functional and structural abnormalities in streptozotocin-induced diabetic CB2 knockout mice. In diabetic mice, deletion of the CB2 receptor albuminuria, the downregulation of podocin and nephrin, mesangial expansion, overexpression of extracellular matrix components, monocyte infiltration, and reduced renal function were all exacerbated. To investigate the relative contributions of podocytes and monocytes to the phenotype of diabetic knockout mice, bone marrow transplantation experiments were performed. The lack of CB2 on bone marrow-derived cells was shown to be important in driving the enhanced glomerular monocyte accrual found in diabetic knockout mice. Absence of CB2 on resident glomerular cells had a major role in worsening diabetic nephropathy, both functional and structural abnormalities, likely by enhanced MCP-1 and CB1 signaling. Studies in cultured podocytes demonstrated that CB2 expression is not altered by a high glucose milieu but is downregulated by mechanical stretch, mimicking glomerular capillary hypertension. Thus, CB2 deletion worsens diabetic nephropathy, independent of bone marrow-derived cells.


Assuntos
Diabetes Mellitus Experimental/complicações , Nefropatias Diabéticas/etiologia , Glomérulos Renais/metabolismo , Receptor CB2 de Canabinoide/deficiência , Estreptozocina , Acetilglucosamina/urina , Albuminúria/etiologia , Albuminúria/metabolismo , Animais , Transplante de Medula Óssea , Linhagem Celular , Proliferação de Células , Quimiocina CCL2/metabolismo , Quimiotaxia de Leucócito , Creatinina/sangue , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Experimental/fisiopatologia , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Nefropatias Diabéticas/fisiopatologia , Matriz Extracelular/metabolismo , Feminino , Glomérulos Renais/patologia , Glomérulos Renais/fisiopatologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Monócitos/metabolismo , Podócitos/metabolismo , Receptor CB2 de Canabinoide/genética , Receptores CCR2/metabolismo , Fatores de Tempo
16.
Nat Commun ; 15(1): 6359, 2024 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-39069558

RESUMO

Systemic light chain (LC) amyloidosis (AL) is a disease where organs are damaged by an overload of a misfolded patient-specific antibody-derived LC, secreted by an abnormal B cell clone. The high LC concentration in the blood leads to amyloid deposition at organ sites. Indeed, cryogenic electron microscopy (cryo-EM) has revealed unique amyloid folds for heart-derived fibrils taken from different patients. Here, we present the cryo-EM structure of heart-derived AL amyloid (AL59) from another patient with severe cardiac involvement. The double-layered structure displays a u-shaped core that is closed by a ß-arc lid and extended by a straight tail. Noteworthy, the fibril harbours an extended constant domain fragment, thus ruling out the variable domain as sole amyloid building block. Surprisingly, the fibrils were abundantly concatenated with a proteinaceous polymer, here identified as collagen VI (COLVI) by immuno-electron microscopy (IEM) and mass-spectrometry. Cryogenic electron tomography (cryo-ET) showed how COLVI wraps around the amyloid forming a helical superstructure, likely stabilizing and protecting the fibrils from clearance. Thus, here we report structural evidence of interactions between amyloid and collagen, potentially signifying a distinct pathophysiological mechanism of amyloid deposits.


Assuntos
Amiloide , Microscopia Crioeletrônica , Amiloidose de Cadeia Leve de Imunoglobulina , Miocárdio , Humanos , Amiloide/metabolismo , Amiloide/química , Amiloide/ultraestrutura , Amiloidose de Cadeia Leve de Imunoglobulina/metabolismo , Amiloidose de Cadeia Leve de Imunoglobulina/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Miocárdio/ultraestrutura , Colágeno/metabolismo , Colágeno/ultraestrutura , Colágeno/química , Pessoa de Meia-Idade , Amiloidose/metabolismo , Amiloidose/patologia , Masculino
17.
Nanoscale ; 15(19): 8740-8753, 2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37097471

RESUMO

Gold nanoparticles (GNPs) are considered promising candidates for healthcare applications, however, their toxicity after long-term exposure to the material remains uncertain. Since the liver is the main filter organ for nanomaterials, this work was aimed at evaluating hepatic accumulation, internalisation and overall safety of well-characterised and endotoxin-free GNPs in healthy mice from 15 minutes to 7 weeks after a single administration. Our data demonstrate that GNPs were rapidly segregated into lysosomes of endothelial cells (LSEC) or Kupffer cells regardless of coating or shape but with different kinetics. Despite the long-lasting accumulation in tissues, the safety of GNPs was confirmed by liver enzymatic levels, as they were rapidly eliminated from the blood circulation and accumulated in the liver without inducing hepatic toxicity. Our results demonstrate that GNPs have a safe and biocompatibile profile despite their long-term accumulation.


Assuntos
Ouro , Nanopartículas Metálicas , Camundongos , Animais , Ouro/toxicidade , Células Endoteliais , Nanopartículas Metálicas/toxicidade , Fígado , Células de Kupffer
18.
Front Immunol ; 14: 1128582, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37228592

RESUMO

Introduction: Gene therapy holds promise to cure various diseases at the fundamental level. For that, efficient carriers are needed for successful gene delivery. Synthetic 'non-viral' vectors, as cationic polymers, are quickly gaining popularity as efficient vectors for transmitting genes. However, they suffer from high toxicity associated with the permeation and poration of the cell membrane. This toxic aspect can be eliminated by nanoconjugation. Still, results suggest that optimising the oligonucleotide complexation, ultimately determined by the size and charge of the nanovector, is not the only barrier to efficient gene delivery. Methods: We herein develop a comprehensive nanovector catalogue comprising different sizes of Au NPs functionalized with two different cationic molecules and further loaded with mRNA for its delivery inside the cell. Results and Discussion: Tested nanovectors showed safe and sustained transfection efficiencies over 7 days, where 50 nm Au NPs displayed the highest transfection rates. Remarkably, protein expression was increased when nanovector transfection was performed combined with chloroquine. Cytotoxicity and risk assessment demonstrated that nanovectors are safe, ascribed to lesser cellular damage due to their internalization and delivery via endocytosis. Obtained results may pave the way to design advanced and efficient gene therapies for safely transferring oligonucleotides.


Assuntos
Ouro , Nanopartículas Metálicas , RNA Mensageiro , Transfecção , Endocitose
19.
Hum Mol Genet ; 19(15): 2998-3010, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20472742

RESUMO

Uromodulin-associated kidney diseases (UAKD) are autosomal-dominant disorders characterized by alteration of urinary concentrating ability, tubulo-interstitial fibrosis, hyperuricaemia and renal cysts at the cortico-medullary junction. UAKD are caused by mutations in UMOD, the gene encoding uromodulin. Although uromodulin is the most abundant protein secreted in urine, its physiological role remains elusive. Several in vitro studies demonstrated that mutations in uromodulin lead to endoplasmic reticulum (ER) retention of mutant protein, but their relevance in vivo has not been studied. We here report on the generation and characterization of the first transgenic mouse model for UAKD. Transgenic mice that express the C147W mutant uromodulin (Tg(Umod)(C147W)), corresponding to the well-established patient mutation C148W, were compared with expression-matched transgenic mice expressing the wild-type protein (Tg(Umod)(wt)). Tg(Umod)(C147W) mice recapitulate most of the UAKD features, with urinary concentrating defect of renal origin and progressive renal injury, i.e. tubulo-interstitial fibrosis with inflammatory cell infiltration, tubule dilation and specific damage of the thick ascending limb of Henle's loop, leading to mild renal failure. As observed in patients, Tg(Umod)(C147W) mice show a marked reduction of urinary uromodulin excretion. Mutant uromodulin trafficking to the plasma membrane is indeed impaired as it is retained in the ER of expressing cells leading to ER hyperplasia. The Tg(Umod)(C147W) mice represent a unique model that recapitulates most of the features associated with UAKD. Our data clearly demonstrate a gain-of-toxic function of uromodulin mutations providing insights into the pathogenetic mechanism of the disease. These findings may also be relevant for other tubulo-interstitial or ER-storage disorders.


Assuntos
Túbulos Renais/patologia , Mucoproteínas/metabolismo , Insuficiência Renal/complicações , Insuficiência Renal/urina , Sequência de Aminoácidos , Animais , Modelos Animais de Doenças , Progressão da Doença , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/ultraestrutura , Inflamação/patologia , Espaço Intracelular/metabolismo , Túbulos Renais/ultraestrutura , Camundongos , Camundongos Transgênicos , Modelos Biológicos , Dados de Sequência Molecular , Mucoproteínas/química , Proteínas Mutantes/metabolismo , Transporte Proteico , Insuficiência Renal/patologia , Uromodulina , Privação de Água
20.
Am J Pathol ; 178(3): 1257-69, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21356376

RESUMO

The metabotropic glutamate (mGlu) receptor 1 (GRM1) has been shown to play an important role in neuronal cells by triggering, through calcium release from intracellular stores, various signaling pathways that finally modulate neuron excitability, synaptic plasticity, and mechanisms of feedback regulation of neurotransmitter release. Herein, we show that Grm1 is expressed in glomerular podocytes and that a glomerular phenotype is exhibited by Grm1(crv4) mice carrying a spontaneous recessive inactivating mutation of the gene. Homozygous Grm1(crv4/crv4) and, to a lesser extent, heterozygous mice show albuminuria, podocyte foot process effacement, and reduced levels of nephrin and other proteins known to contribute to the maintenance of podocyte cell structure. Overall, the present data extend the role of mGlu1 receptor to the glomerular filtration barrier. The regulatory action of mGlu1 receptor in dendritic spine morphology and in the control of glutamate release is well acknowledged in neuronal cells. Analogously, we speculate that mGlu1 receptor may regulate foot process morphology and intercellular signaling in the podocyte.


Assuntos
Albuminúria/patologia , Glomérulos Renais/patologia , Receptores de Glutamato Metabotrópico/deficiência , Albuminúria/complicações , Albuminúria/metabolismo , Animais , Western Blotting , Células Cultivadas , Doxorrubicina/farmacologia , Imunofluorescência , Regulação da Expressão Gênica/efeitos dos fármacos , Inativação Gênica/efeitos dos fármacos , Humanos , Córtex Renal/efeitos dos fármacos , Córtex Renal/metabolismo , Córtex Renal/patologia , Nefropatias/complicações , Nefropatias/metabolismo , Nefropatias/patologia , Glomérulos Renais/metabolismo , Glomérulos Renais/ultraestrutura , Camundongos , Fenótipo , Podócitos/efeitos dos fármacos , Podócitos/metabolismo , Podócitos/patologia , Receptores de Glutamato Metabotrópico/genética , Receptores de Glutamato Metabotrópico/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção
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