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1.
Cell Death Dis ; 14(8): 500, 2023 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-37542079

RESUMO

In the adult mammalian brain, neural stem cells (NSCs) located in highly restricted niches sustain the generation of new neurons that integrate into existing circuits. A reduction in adult neurogenesis is linked to ageing and neurodegeneration, whereas dysregulation of proliferation and survival of NSCs have been hypothesized to be at the origin of glioma. Thus, unravelling the molecular underpinnings of the regulated activation that NSCs must undergo to proliferate and generate new progeny is of considerable relevance. Current research has identified cues promoting or restraining NSCs activation. Yet, whether NSCs depend on external signals to survive or if intrinsic factors establish a threshold for sustaining their viability remains elusive, even if this knowledge could involve potential for devising novel therapeutic strategies. Kidins220 (Kinase D-interacting substrate of 220 kDa) is an essential effector of crucial pathways for neuronal survival and differentiation. It is dramatically altered in cancer and in neurological and neurodegenerative disorders, emerging as a regulatory molecule with important functions in human disease. Herein, we discover severe neurogenic deficits and hippocampal-based spatial memory defects accompanied by increased neuroblast death and high loss of newly formed neurons in Kidins220 deficient mice. Mechanistically, we demonstrate that Kidins220-dependent activation of AKT in response to EGF restraints GSK3 activity preventing NSCs apoptosis. We also show that NSCs with Kidins220 can survive with lower concentrations of EGF than the ones lacking this molecule. Hence, Kidins220 levels set a molecular threshold for survival in response to mitogens, allowing adult NSCs growth and expansion. Our study identifies Kidins220 as a key player for sensing the availability of growth factors to sustain adult neurogenesis, uncovering a molecular link that may help paving the way towards neurorepair.


Assuntos
Células-Tronco Adultas , Células-Tronco Neurais , Adulto , Animais , Humanos , Camundongos , Células-Tronco Adultas/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Hipocampo/metabolismo , Mamíferos , Células-Tronco Neurais/metabolismo , Neurogênese/fisiologia , Neurônios/metabolismo
2.
Nature ; 619(7968): 129-134, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37380770

RESUMO

While sleeping, many vertebrate groups alternate between at least two sleep stages: rapid eye movement and slow wave sleep1-4, in part characterized by wake-like and synchronous brain activity, respectively. Here we delineate neural and behavioural correlates of two stages of sleep in octopuses, marine invertebrates that evolutionarily diverged from vertebrates roughly 550 million years ago (ref. 5) and have independently evolved large brains and behavioural sophistication. 'Quiet' sleep in octopuses is rhythmically interrupted by approximately 60-s bouts of pronounced body movements and rapid changes in skin patterning and texture6. We show that these bouts are homeostatically regulated, rapidly reversible and come with increased arousal threshold, representing a distinct 'active' sleep stage. Computational analysis of active sleep skin patterning reveals diverse dynamics through a set of patterns conserved across octopuses and strongly resembling those seen while awake. High-density electrophysiological recordings from the central brain reveal that the local field potential (LFP) activity during active sleep resembles that of waking. LFP activity differs across brain regions, with the strongest activity during active sleep seen in the superior frontal and vertical lobes, anatomically connected regions associated with learning and memory function7-10. During quiet sleep, these regions are relatively silent but generate LFP oscillations resembling mammalian sleep spindles11,12 in frequency and duration. The range of similarities with vertebrates indicates that aspects of two-stage sleep in octopuses may represent convergent features of complex cognition.


Assuntos
Sistema Nervoso Central , Tegumento Comum , Octopodiformes , Sono , Vigília , Animais , Mamíferos/fisiologia , Octopodiformes/fisiologia , Sono/fisiologia , Sono REM/fisiologia , Vigília/fisiologia , Tegumento Comum/inervação , Tegumento Comum/fisiologia , Movimento/fisiologia , Fatores de Tempo , Medida de Potenciais de Campo Local , Aprendizagem/fisiologia , Sistema Nervoso Central/anatomia & histologia , Sistema Nervoso Central/fisiologia , Nível de Alerta/fisiologia
3.
Oncogenesis ; 12(1): 20, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37045830

RESUMO

Spry2 is a molecular modulator of tyrosine kinase receptor signaling pathways that has cancer-type-specific effects. Mammalian Spry2 protein undergoes tyrosine and serine phosphorylation in response to growth factor stimulation. Spry2 expression is distinctly altered in various cancer types. Inhibition of the proteasome functionality results in reduced intracellular Spry2 degradation. Using in vitro and in vivo assays, we show that protein kinase D (PKD) phosphorylates Spry2 at serine 112 and interacts in vivo with the C-terminal half of this protein. Importantly, missense mutation of Ser112 decreases the rate of Spry2 intracellular protein degradation. Either knocking down the expression of all three mammalian PKD isoforms or blocking their kinase activity with a specific inhibitor contributes to the stabilization of Spry2 wild-type protein. Downregulation of CSN3, a component of the COP9/Signalosome that binds PKD, significantly increases the half-life of Spry2 wild-type protein but does not affect the stability of a Spry2 after mutating Ser112 to the non-phosphorylatable residue alanine. Our data demonstrate that both PKD and the COP9/Signalosome play a significant role in control of Spry2 intracellular stability and support the consideration of the PKD/COP9 complex as a potential therapeutic target in tumors where Spry2 expression is reduced.

4.
Int J Mol Sci ; 24(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36982724

RESUMO

Aquaporin-4 (AQP4) plays a crucial role in brain water circulation and is considered a therapeutic target in hydrocephalus. Congenital hydrocephalus is associated with a reaction of astrocytes in the periventricular white matter both in experimental models and human cases. A previous report showed that bone marrow-derived mesenchymal stem cells (BM-MSCs) transplanted into the lateral ventricles of hyh mice exhibiting severe congenital hydrocephalus are attracted by the periventricular astrocyte reaction, and the cerebral tissue displays recovery. The present investigation aimed to test the effect of BM-MSC treatment on astrocyte reaction formation. BM-MSCs were injected into the lateral ventricles of four-day-old hyh mice, and the periventricular reaction was detected two weeks later. A protein expression analysis of the cerebral tissue differentiated the BM-MSC-treated mice from the controls and revealed effects on neural development. In in vivo and in vitro experiments, BM-MSCs stimulated the generation of periventricular reactive astrocytes overexpressing AQP4 and its regulatory protein kinase D-interacting substrate of 220 kDa (Kidins220). In the cerebral tissue, mRNA overexpression of nerve growth factor (NGF), vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1 (HIF1α), and transforming growth factor beta 1 (TGFß1) could be related to the regulation of the astrocyte reaction and AQP4 expression. In conclusion, BM-MSC treatment in hydrocephalus can stimulate a key developmental process such as the periventricular astrocyte reaction, where AQP4 overexpression could be implicated in tissue recovery.


Assuntos
Hidrocefalia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Camundongos , Humanos , Animais , Astrócitos/metabolismo , Aquaporina 4/genética , Aquaporina 4/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Células-Tronco Mesenquimais/metabolismo , Hidrocefalia/terapia , Hidrocefalia/metabolismo , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo
5.
J Clin Pathol ; 76(5): 327-332, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-34903610

RESUMO

AIMS: The aim of this study is to extend the analysis of the Lung Cancer Biomarker Testing Registry (LungPath), by analysing the techniques used in the determination of epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1) and programmed death ligand-1 (PD-L1) for the diagnostic of patients with advanced non-small-cell lung cancer (NSCLC). METHODS: Information of the technique used for the determination of EGFR, ALK, ROS1 and PD-L1 was recorded from March 2018 to January 2019 from 44 centres, but only 34 centres matched with the 38 centres previously analysed, allowing to analyse the techniques used in 8970 matched determinations of EGFR, ALK, ROS1 and PD-L1. Therefore, a by-centre analysis studied the level of implementation of the techniques in the 44 centres, while a by-determination analysis made it possible to assess the overall frequency of the techniques used on the 9134 matched samples. RESULTS: By-centre analysis showed that only 46.5% and 25.6% of the centres used reflex strategies for ALK and ROS1 determination, respectively. By-determination analysis showed that 94.4% of EGFR determinations were performed by PCR, 80.7% of ALK determinations were performed by IHC with clone D5F3, while 55.7% of ROS1 determinations were performed by IHC with clone D4D6. 22C3 were the PD-L1 clone more used (43.5%) followed by SP263 clone (31.1%). CONCLUSIONS: The real-world evidence obtained from LungPath shows the effort of Spanish hospitals in performing biomarker determination in NSCLC with different methodologies despite that next-generation sequencing (NGS) utilisation in the year of the analysis was low. Biomarker determination results could be optimised with the incorporation of sequencing methods such as NGS in pathology departments.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Antígeno B7-H1 , Proteínas Tirosina Quinases , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/análise , Estudos Prospectivos , Proteínas Proto-Oncogênicas/metabolismo , Receptores ErbB/genética , Pulmão/patologia , Sistema de Registros
6.
Proc Natl Acad Sci U S A ; 119(29): e2204527119, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35858325

RESUMO

Mice with insulin receptor (IR)-deficient astrocytes (GFAP-IR knockout [KO] mice) show blunted responses to insulin and reduced brain glucose uptake, whereas IR-deficient astrocytes show disturbed mitochondrial responses to glucose. While exploring the functional impact of disturbed mitochondrial function in astrocytes, we observed that GFAP-IR KO mice show uncoupling of brain blood flow with glucose uptake. Since IR-deficient astrocytes show higher levels of reactive oxidant species (ROS), this leads to stimulation of hypoxia-inducible factor-1α and, consequently, of the vascular endothelial growth factor angiogenic pathway. Indeed, GFAP-IR KO mice show disturbed brain vascularity and blood flow that is normalized by treatment with the antioxidant N-acetylcysteine (NAC). NAC ameliorated high ROS levels, normalized angiogenic signaling and mitochondrial function in IR-deficient astrocytes, and normalized neurovascular coupling in GFAP-IR KO mice. Our results indicate that by modulating glucose uptake and angiogenesis, insulin receptors in astrocytes participate in neurovascular coupling.


Assuntos
Astrócitos , Encéfalo , Insulina , Neovascularização Fisiológica , Acoplamento Neurovascular , Animais , Astrócitos/metabolismo , Encéfalo/irrigação sanguínea , Proteína Glial Fibrilar Ácida/genética , Glucose/metabolismo , Insulina/metabolismo , Camundongos , Camundongos Knockout , Espécies Reativas de Oxigênio/metabolismo , Receptor de Insulina/genética , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
7.
Sci Rep ; 12(1): 5227, 2022 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-35347207

RESUMO

Coleoid cephalopods camouflage on timescales of seconds to match their visual surroundings. To date, studies of cephalopod camouflage-to-substrate have been focused primarily on benthic cuttlefish and octopus, because they are readily found sitting on the substrate. In contrast to benthic cephalopods, oval squid (Sepioteuthis lessoniana species complex) are semi-pelagic animals that spend most of their time in the water column. In this study, we demonstrate that in captivity, S. lessoniana Sp.2 (Shiro-ika, white-squid) from the Okinawa archipelago, Japan, adapts the coloration of their skin using their chromatophores according to the background substrate. We show that if the animal moves between substrates of different reflectivity, the body patterning is changed to match. Chromatophore matching to substrate has not been reported in any loliginid cephalopod under laboratory conditions. Adaptation of the chromatophore system to the bottom substrate in the laboratory is a novel experimental finding that establishes oval squid as laboratory model animals for further research on camouflage.


Assuntos
Cromatóforos , Octopodiformes , Animais , Decapodiformes , Japão
8.
J Clin Pathol ; 75(3): 193-200, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33722840

RESUMO

AIM: The aim of this study was to describe the testing rate and frequency of molecular alterations observed in the Lung Cancer Biomarker Testing Registry (LungPath). METHODS: A descriptive study of NSCLC biomarker determinations collected from March 2018 to January 2019, from 38 Spanish hospitals, was carried out. Only adenocarcinoma and not otherwise specified histologies were included for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1) and programmed death ligand-1 (PD-L1) expression. The testing rate and the positivity rate were calculated. Multivariate logistic regression was used to explore the joint relationship between independent explanatory factors and both testing and positivity rates. Two models were adjusted: one with sample type and histology as independent factors, and the other adding the testing rate or the positivity rate of the other biomarkers. RESULTS: 3226 patient samples were analysed, where EGFR, ALK, ROS1 and PD-L1 information was collected (a total of 12 904 determinations). Overall, 9118 (71.4%) determinations were finally assessed. EGFR (91.4%) and ALK (80.1%) were the mainly tested biomarkers. Positivity rates for EGFR, ALK, ROS1 and PD-L1 were 13.6%, 3.4%, 2.0% and 49.2%, respectively. Multivariate models showed a lower testing rate for ALK in surgical pieces, fine-needle aspiration or other types of samples versus biopsies. CONCLUSIONS: Despite the high testing rate in EGFR and ALK in NSCLC, the real-world evidence obtained from the LungPath demonstrates that ROS1 and PD-L1 were not determined in a significant portion of patients. LungPath provides crucial information to improve the coverage in molecular testing in lung cancer, to monitor the positivity rate and the introduction of new biomarker testing in clinical practice.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Neoplasias Pulmonares/diagnóstico , Quinase do Linfoma Anaplásico/análise , Antígeno B7-H1/análise , Carcinoma Pulmonar de Células não Pequenas/patologia , Receptores ErbB/análise , Humanos , Modelos Logísticos , Pulmão/patologia , Neoplasias Pulmonares/patologia , Técnicas de Diagnóstico Molecular , Estudos Prospectivos , Proteínas Tirosina Quinases/análise , Proteínas Proto-Oncogênicas/análise , Sistema de Registros , Espanha
9.
Sci Transl Med ; 13(613): eabe7104, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34586830

RESUMO

Huntington's disease (HD) is a hereditary neurodegenerative disorder of the basal ganglia for which disease-modifying treatments are not yet available. Although gene-silencing therapies are currently being tested, further molecular mechanisms must be explored to identify druggable targets for HD. Cytoplasmic polyadenylation element binding proteins 1 to 4 (CPEB1 to CPEB4) are RNA binding proteins that repress or activate translation of CPE-containing transcripts by shortening or elongating their poly(A) tail. Here, we found increased CPEB1 and decreased CPEB4 protein in the striatum of patients and mouse models with HD. This correlated with a reprogramming of polyadenylation in 17.3% of the transcriptome, markedly affecting neurodegeneration-associated genes including PSEN1, MAPT, SNCA, LRRK2, PINK1, DJ1, SOD1, TARDBP, FUS, and HTT and suggesting a new molecular mechanism in neurodegenerative disease etiology. We found decreased protein content of top deadenylated transcripts, including striatal atrophy­linked genes not previously related to HD, such as KTN1 and the easily druggable SLC19A3 (the ThTr2 thiamine transporter). Mutations in SLC19A3 cause biotin-thiamine­responsive basal ganglia disease (BTBGD), a striatal disorder that can be treated with a combination of biotin and thiamine. Similar to patients with BTBGD, patients with HD demonstrated decreased thiamine in the cerebrospinal fluid. Furthermore, patients and mice with HD showed decreased striatal concentrations of thiamine pyrophosphate (TPP), the metabolically active form of thiamine. High-dose biotin and thiamine treatment prevented TPP deficiency in HD mice and attenuated the radiological, neuropathological, and motor HD-like phenotypes, revealing an easily implementable therapy that might benefit patients with HD.


Assuntos
Doença de Huntington , Poliadenilação , Fatores de Transcrição/genética , Fatores de Poliadenilação e Clivagem de mRNA/genética , Humanos , Doença de Huntington/genética , Doença de Huntington/terapia , Proteínas de Membrana Transportadoras , Transcriptoma
10.
Ecol Evol ; 11(16): 11449-11456, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34429932

RESUMO

Allopatry has traditionally been viewed as the primary driver of speciation in marine taxa, but the geography of the marine environment and the larval dispersal capabilities of many marine organisms render this view somewhat questionable. In marine fishes, one of the earliest and most highly cited empirical examples of ecological speciation with gene flow is the slippery dick wrasse, Halichoeres bivittatus. Evidence for this cryptic or incipient speciation event was primarily in the form of a deep divergence in a single mitochondrial locus between the northern and southern Gulf of Mexico, combined with a finding that these two haplotypes were associated with different habitat types ("tropical" vs. "subtropical") in the Florida Keys and Bermuda, where they overlap. Here, we examine habitat assortment in the Florida Keys using a broader sampling of populations and habitat types than were available for the original study. We find no evidence to support the claim that haplotype frequencies differ between habitat types, and little evidence to support any differences between populations in the Keys. These results undermine claims of ecological speciation with gene flow in Halichoeres bivittatus. Future claims of this type should be supported by multiple lines of evidence that illuminate potential mechanisms and allow researchers to rule out alternative explanations for spatial patterns of genetic differences.

11.
Mol Psychiatry ; 26(11): 6411-6426, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34002021

RESUMO

Several psychiatric, neurologic and neurodegenerative disorders present increased brain ventricles volume, being hydrocephalus the disease with the major manifestation of ventriculomegaly caused by the accumulation of high amounts of cerebrospinal fluid (CSF). The molecules and pathomechanisms underlying cerebral ventricular enlargement are widely unknown. Kinase D interacting substrate of 220 kDa (KIDINS220) gene has been recently associated with schizophrenia and with a novel syndrome characterized by spastic paraplegia, intellectual disability, nystagmus and obesity (SINO syndrome), diseases frequently occurring with ventriculomegaly. Here we show that Kidins220, a transmembrane protein effector of various key neuronal signalling pathways, is a critical regulator of CSF homeostasis. We observe that both KIDINS220 and the water channel aquaporin-4 (AQP4) are markedly downregulated at the ventricular ependymal lining of idiopathic normal pressure hydrocephalus (iNPH) patients. We also find that Kidins220 deficient mice develop ventriculomegaly accompanied by water dyshomeostasis and loss of AQP4 in the brain ventricular ependymal layer and astrocytes. Kidins220 is a known cargo of the SNX27-retromer, a complex that redirects endocytosed plasma membrane proteins (cargos) back to the cell surface, thus avoiding their targeting to lysosomes for degradation. Mechanistically, we show that AQP4 is a novel cargo of the SNX27-retromer and that Kidins220 deficiency promotes a striking and unexpected downregulation of the SNX27-retromer that results in AQP4 lysosomal degradation. Accordingly, SNX27 silencing decreases AQP4 levels in wild-type astrocytes whereas SNX27 overexpression restores AQP4 content in Kidins220 deficient astrocytes. Together our data suggest that the KIDINS220-SNX27-retromer-AQP4 pathway is involved in human ventriculomegaly and open novel therapeutic perspectives.


Assuntos
Hidrocefalia , Animais , Aquaporina 4/genética , Aquaporina 4/metabolismo , Epêndima/metabolismo , Humanos , Hidrocefalia/genética , Hidrocefalia/metabolismo , Lisossomos/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Nexinas de Classificação/genética
12.
Ecol Evol ; 11(24): 18719-18732, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35003704

RESUMO

Hemidactylus mabouia is one of the most successful, widespread invasive reptile species and has become ubiquitous across tropical urban settings in the Western Hemisphere. Its ability to thrive in close proximity to humans has been linked to the rapid disappearance of native geckos. However, aspects of Hemidactylus mabouia natural history and ecomorphology, often assumed to be linked with this effect on native populations, remain understudied or untested. Here, we combine data from ∂15N and ∂13C stable isotopes, stomach contents, and morphometric analyses of traits associated with feeding and locomotion to test alternate hypotheses of displacement between H. mabouia and a native gecko, Phyllodactylus martini, on the island of Curaçao. We demonstrate substantial overlap of invertebrate prey resources between the species, with H. mabouia stomachs containing larger arthropod prey as well as vertebrate prey. We additionally show that H. mabouia possesses several morphological advantages, including larger sizes in feeding-associated traits and limb proportions that could offer a propulsive locomotor advantage on vertical surfaces. Together, these findings provide the first support for the hypotheses that invasive H. mabouia and native P. martini overlap in prey resources and that H. mabouia possess ecomorphological advantages over P. martini. This work provides critical context for follow-up studies of H. mabouia and P. martini natural history and direct behavioral experiments that may ultimately illuminate the mechanisms underlying displacement on this island and act as a potential model for other systems with Hemidactylus mabouia invasions.

13.
Haematologica ; 105(3): 730-740, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31221787

RESUMO

Metastases, the major cause of death from cancer, require cells' acquisition of the ability to migrate and involve multiple steps, including local tumor cell invasion and basement membrane penetration. Certain lymphoid tumors are highly metastatic, but the mechanisms of invasion by lymphoma cells are poorly understood. We recently showed that CDCA7, a protein induced by MYC, is overexpressed in lymphoid tumors and that its knockdown decreases lymphoid tumor growth without inhibiting the proliferation of normal cells. Here we show that CDCA7 is critical for invasion and migration of lymphoma cells. Indeed, CDCA7 knockdown in lymphoma cells limited tumor cell invasion in matrigel-coated transwell plates and tumor invasion of neighboring tissues in a mouse xenograft model and in a zebrafish model of cell invasion. CDCA7 silencing markedly inhibited lymphoma cell migration on fibronectin without modifying cell adhesion to this protein. Instead, CDCA7 knockdown markedly disrupted the precise dynamic reorganization of actomyosin and tubulin cytoskeletons required for efficient migration. In particular, CDCA7 silencing impaired tubulin and actomyosin cytoskeleton polarization, increased filamentous actin formation, and induced myosin activation. Of note, inhibitors of actin polymerization, myosin II, or ROCK reestablished the migration capacity of CDCA7-silenced lymphoma cells. Given the critical role of CDCA7 in lymphoma-genesis and invasion, therapies aimed at inhibiting its expression or activity might provide significant control of lymphoma growth, invasion, and metastatic dissemination.


Assuntos
Linfoma , Peixe-Zebra , Animais , Carcinogênese , Linhagem Celular Tumoral , Movimento Celular , Citoesqueleto , Linfoma/genética , Camundongos , Invasividade Neoplásica
14.
Brain Pathol ; 30(1): 120-136, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31264746

RESUMO

Huntington's disease (HD) is an inherited progressive neurodegenerative disease characterized by brain atrophy particularly in the striatum that produces motor impairment, and cognitive and psychiatric disturbances. Multiple pathogenic mechanisms have been proposed including dysfunctions in neurotrophic support and calpain-overactivation, among others. Kinase D-interacting substrate of 220 kDa (Kidins220), also known as ankyrin repeat-rich membrane spanning (ARMS), is an essential mediator of neurotrophin signaling. In adult brain, Kidins220 presents two main isoforms that differ in their carboxy-terminal length and critical protein-protein interaction domains. These variants are generated through alternative terminal exon splicing of the conventional exon 32 (Kidins220-C32) and the recently identified exon 33 (Kidins220-C33). The lack of domains encoded by exon 32 involved in key neuronal functions, including those controlling neurotrophin pathways, pointed to Kidins220-C33 as a form detrimental for neurons. However, the functional role of Kidins220-C33 in neurodegeneration or other pathologies, including HD, has not been explored. In the present work, we discover an unexpected selective downregulation of Kidins220-C33, in the striatum of HD patients, as well as in the R6/1 HD mouse model starting at early symptomatic stages. These changes are C33-specific as Kidins220-C32 variant remains unchanged. We also find the early decrease in Kidins220-C33 levels takes place in neurons, suggesting an unanticipated neuroprotective role for this isoform. Finally, using ex vivo assays and primary neurons, we demonstrate that Kidins220-C33 is downregulated by mechanisms that depend on the activation of the protease calpain. Altogether, these results strongly suggest that calpain-mediated Kidins220-C33 proteolysis modulates onset and/or progression of HD.


Assuntos
Doença de Huntington/genética , Doença de Huntington/metabolismo , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Adulto , Idoso , Processamento Alternativo , Animais , Corpo Estriado/metabolismo , Modelos Animais de Doenças , Éxons/genética , Feminino , Hipocampo/metabolismo , Humanos , Doença de Huntington/patologia , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/metabolismo , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurônios/metabolismo , Neurônios/patologia , Ligação Proteica , Isoformas de Proteínas/genética , Transdução de Sinais
15.
Cell Death Dis ; 10(7): 535, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31296845

RESUMO

Excitotoxic neuronal death induced by high concentrations of glutamate is a pathological event common to multiple acute or chronic neurodegenerative diseases. Excitotoxicity is mediated through overactivation of the N-Methyl-D-aspartate type of ionotropic glutamate receptors (NMDARs). Physiological stimulation of NMDARs triggers their endocytosis from the neuronal surface, inducing synaptic activity and survival. However almost nothing is known about the internalization of overactivated NMDARs and their interacting proteins, and how this endocytic process is connected with neuronal death has been poorly explored. Kinase D-interacting substrate of 220 kDa (Kidins220), also known as ankyrin repeat-rich membrane spanning (ARMS), is a component of NMDAR complexes essential for neuronal viability by the control of ERK activation. Here we have investigated Kidins220 endocytosis induced by NMDAR overstimulation and the participation of this internalization step in the molecular mechanisms of excitotoxicity. We show that excitotoxicity induces Kidins220 and GluN1 traffic to the Golgi apparatus (GA) before Kidins220 is degraded by the protease calpain. We also find that excitotoxicity triggers an early activation of Rap1-GTPase followed by its inactivation. Kidins220 excitotoxic endocytosis and subsequent calpain-mediated downregulation governs this late inactivation of Rap1 that is associated to decreases in ERK activity preceding neuronal death. Furthermore, we identify the molecular mechanisms involved in the excitotoxic shutoff of Kidins220/Rap1/ERK prosurvival cascade that depends on calpain processing of Rap1-activation complexes. Our data fit in a model where Kidins220 targeting to the GA during early excitotoxicity would facilitate Rap1 activation and subsequent stimulation of ERK. At later times, activation of Golgi-associated calpain, would promote the degradation of GA-targeted Kidins220 and two additional components of the specific Rap1 activation complex, PDZ-GEF1, and S-SCAM. In this way, late excitotoxicity would turn off Rap1/ERK cascade and compromise neuronal survival.


Assuntos
Calpaína/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Fosfoproteínas/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Proteínas rap1 de Ligação ao GTP/metabolismo , Animais , Calpaína/antagonistas & inibidores , Morte Celular/efeitos dos fármacos , Morte Celular/genética , Células Cultivadas , Endocitose/efeitos dos fármacos , Endocitose/genética , Endossomos/metabolismo , Ácido Glutâmico/metabolismo , Complexo de Golgi/efeitos dos fármacos , Proteínas de Membrana/genética , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/enzimologia , Neurônios/ultraestrutura , Fosfoproteínas/genética , Ratos , Ratos Wistar , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/genética , Transdução de Sinais/genética , Proteínas rab5 de Ligação ao GTP/metabolismo , Proteínas rap1 de Ligação ao GTP/antagonistas & inibidores , Proteínas rap1 de Ligação ao GTP/genética
16.
J Alzheimers Dis Rep ; 3(1): 47-57, 2019 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-30842997

RESUMO

The nematode Caenorhabditis elegans (C. elegans) is a powerful model organism to study lifespan and aging, protein aggregation, and neurodegeneration, as well as to carry out drug screenings. The C. elegans strain aex-3/T337 expresses human pathogenic V337M mutant tau under a pan-neuronal promoter and presents uncoordinated locomotion, accumulation of phosphorylated insoluble tau, and shortened lifespan. Herein we have used this strain to assay two compounds that could affect tau aggregation and/or phosphorylation, and looked for phenotypic changes in their lifespan and motility. The first compound is Thioflavin T (ThT), a member of the tetracycline family with protein antiaggregant properties, yet to be tested in a tauopathy model. The second is a novel small molecule, NP103, a highly selective inhibitor of glycogen synthase kinase-3 (GSK-3), the main kinase contributing to pathogenic tau hyperphosphorylation. Importantly, we find that ThT extends lifespan of aex-3/T337 worms as it does with control N2 animals, showing both strains similar locomotion features under this treatment. By contrast, NP103 improves the paralysis phenotype of aex-3/T337 mutants but not their lifespan. Our results show that both treatments present beneficial effects for this model of tauopathy and encourage pursuing further investigations on their therapeutic potential for AD and other tauopathies.

17.
J Exp Biol ; 222(Pt 1)2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30446538

RESUMO

Sleep is a state of immobility characterized by three key criteria: an increased threshold of arousal, rapid reversal to an alert state and evidence of homeostatic 'rebound sleep' in which there is an increase in the time spent in this quiescent state following sleep deprivation. Common European cuttlefish, Sepia officinalis, show states of quiescence during which they meet the last two of these three criteria, yet also show spontaneous bursts of arm and eye movements that accompany rapid changes in chromatophore patterns in the skin. Here, we report that this rapid eye movement sleep-like (REMS-like) state is cyclic in nature. Iterations of the REMS-like state last 2.42±0.22 min (mean±s.e.m.) and alternate with 34.01±1.49 min of the quiescent sleep-like state for durations lasting 176.89±36.71 min. We found clear evidence that this REMS-like state (i) occurs in animals younger than previously reported; (ii) follows an ultradian pattern; (iii) includes intermittent dynamic chromatophore patterning, representing fragments of normal patterning seen in the waking state for a wide range of signaling and camouflage; and (iv) shows variability in the intensity of expression of these skin patterns between and within individuals. These data suggest that cephalopods, which are mollusks with an elaborate brain and complex behavior, possess a sleep-like state that resembles behaviorally the vertebrate REM sleep state, although the exact nature and mechanism of this form of sleep may differ from that of vertebrates.


Assuntos
Cromatóforos/fisiologia , Ritmo Circadiano , Sepia/fisiologia , Sono REM , Animais , Variação Biológica Individual , Pigmentação
19.
Haematologica ; 103(10): 1669-1678, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29880607

RESUMO

Tumor formation involves the acquisition of numerous capacities along the progression from a normal cell into a malignant cell, including limitless proliferation (immortalization) and anchorage-independent growth, a capacity that correlates extremely well with tumorigenesis. Great efforts have been made to uncover genes involved in tumor formation, but most genes identified participate in processes related to cell proliferation. Accordingly, therapies targeting these genes also affect the proliferation of normal cells. To identify potential targets for therapeutic intervention more specific to tumor cells, we looked for genes implicated in the acquisition of anchorage-independent growth and in vivo tumorigenesis capacity. A transcriptomic analysis identified CDCA7 as a candidate gene. Indeed, CDCA7 protein was upregulated in Burkitt's lymphoma cell lines and human tumor biopsy specimens relative to control cell lines and tissues, respectively. CDCA7 levels were also markedly elevated in numerous T and B-lymphoid tumor cell lines. While CDCA7 was not required for anchorage-dependent growth of normal fibroblasts or non-malignant lymphocytes, it was essential but not sufficient for anchorage-independent growth of lymphoid tumor cells and for lymphomagenesis. These data suggest that therapies aimed at inhibiting CDCA7 expression or function might significantly decrease the growth of lymphoid tumors.


Assuntos
Linfoma de Burkitt/metabolismo , Carcinogênese/metabolismo , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Proteínas de Neoplasias/biossíntese , Proteínas Nucleares/biossíntese , Regulação para Cima , Linfoma de Burkitt/genética , Linfoma de Burkitt/patologia , Carcinogênese/genética , Carcinogênese/patologia , Feminino , Células HCT116 , Células HeLa , Humanos , Células Jurkat , Células K562 , Masculino , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Células U937
20.
J Evol Biol ; 31(8): 1082-1092, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29808568

RESUMO

Understanding how organismal design evolves in response to environmental challenges is a central goal of evolutionary biology. In particular, assessing the extent to which environmental requirements drive general design features among distantly related groups is a major research question. The visual system is a critical sensory apparatus that evolves in response to changing light regimes. In vertebrates, the optic tectum is the primary visual processing centre of the brain and yet it is unclear how or whether this structure evolves while lineages adapt to changes in photic environment. On one hand, dim-light adaptation is associated with larger eyes and enhanced light-gathering power that could require larger information processing capacity. On the other hand, dim-light vision may evolve to maximize light sensitivity at the cost of acuity and colour sensitivity, which could require less processing power. Here, we use X-ray microtomography and phylogenetic comparative methods to examine the relationships between diel activity pattern, optic morphology, trophic guild and investment in the optic tectum across the largest radiation of vertebrates-teleost fishes. We find that despite driving the evolution of larger eyes, enhancement of the capacity for dim-light vision generally is accompanied by a decrease in investment in the optic tectum. These findings underscore the importance of considering diel activity patterns in comparative studies and demonstrate how vision plays a role in brain evolution, illuminating common design principles of the vertebrate visual system.


Assuntos
Adaptação Ocular , Evolução Biológica , Peixes/fisiologia , Luz , Colículos Superiores/fisiologia , Animais , Ritmo Circadiano , Peixes/genética , Neurônios/fisiologia , Filogenia , Colículos Superiores/citologia , Microtomografia por Raio-X/veterinária
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