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1.
Int J Mol Sci ; 22(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34445792

RESUMO

Otolin-1 is a scaffold protein of otoliths and otoconia, calcium carbonate biominerals from the inner ear. It contains a gC1q domain responsible for trimerization and binding of Ca2+. Knowledge of a structure-function relationship of gC1q domain of otolin-1 is crucial for understanding the biology of balance sensing. Here, we show how natural variants alter the structure of gC1q otolin-1 and how Ca2+ are able to revert some effects of the mutations. We discovered that natural substitutions: R339S, R342W and R402P negatively affect the stability of apo-gC1q otolin-1, and that Q426R has a stabilizing effect. In the presence of Ca2+, R342W and Q426R were stabilized at higher Ca2+ concentrations than the wild-type form, and R402P was completely insensitive to Ca2+. The mutations affected the self-association of gC1q otolin-1 by inducing detrimental aggregation (R342W) or disabling the trimerization (R402P) of the protein. Our results indicate that the natural variants of gC1q otolin-1 may have a potential to cause pathological changes in otoconia and otoconial membrane, which could affect sensing of balance and increase the probability of occurrence of benign paroxysmal positional vertigo (BPPV).


Assuntos
Proteínas da Matriz Extracelular/genética , Mutação/genética , Domínios Proteicos/genética , Sequência de Aminoácidos , Vertigem Posicional Paroxística Benigna/genética , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Humanos
2.
FASEB J ; 35(9): e21837, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34383985

RESUMO

Overwhelming evidence indicates that excessive stimulation of innate immune receptors of the NOD-like receptor (NLR) family causes significant damage to multiple tissues, yet the role of these proteins in bone metabolism is not well known. Here, we studied the interaction between the NLRP3 and NLRC4 inflammasomes in bone homeostasis and disease. We found that loss of NLRP3 or NLRC4 inflammasome attenuated osteoclast differentiation in vitro. At the tissue level, lack of NLRP3, or NLRC4 to a lesser extent, resulted in higher baseline bone mass compared to wild-type (WT) mice, and conferred protection against LPS-induced inflammatory osteolysis. Bone mass accrual in mutant mice correlated with lower serum IL-1ß levels in vivo. Unexpectedly, the phenotype of Nlrp3-deficient mice was reversed upon loss of NLRC4 as bone mass was comparable between WT mice and Nlrp3;Nlrc4 knockout mice. Thus, although bone homeostasis is perturbed to various degrees by the lack of NLRP3 or NLRC4, this tissue appears to function normally upon compound loss of the inflammasomes assembled by these receptors.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Reabsorção Óssea/metabolismo , Osso e Ossos/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Animais , Diferenciação Celular/fisiologia , Homeostase/fisiologia , Inflamação/metabolismo , Interleucina-1beta/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Osteoclastos/metabolismo , Osteólise/metabolismo
3.
Int J Mol Sci ; 22(12)2021 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-34208313

RESUMO

Intrahepatic cholangiocarcinoma (iCCA) is a heterogeneous bile duct cancer with a poor prognosis. Integrin αvß6 (ß6) has been shown to be upregulated in iCCA and is associated with its subclassification and clinicopathological features. In the present study, two ITGB6-knockout HuCCT1 CCA cell lines (ITGB6-ko cells) were established using the clustered regulatory interspaced short palindromic repeats (CRISPR), an associated nuclease 9 (Cas9) system, and single-cell cloning. RNA sequencing analysis, real-time polymerase chain reaction (PCR), and immunofluorescent methods were applied to explore possible downstream factors. ITGB6-ko cells showed significantly decreased expression of integrin ß6 on flow cytometric analysis. Both cell lines exhibited significant inhibition of cell migration and invasion, decreased wound-healing capability, decreased colony formation ability, and cell cycle dysregulation. RNA sequencing and real-time PCR analysis revealed a remarkable decrease in podocalyxin-like protein 2 (PODXL2) expression in ITGB6-ko cells. Colocalization of PODXL2 and integrin ß6 was also observed. S100 calcium-binding protein P and mucin 1, which are associated with CCA subclassification, were downregulated in ITGB6-ko cells. These results describe the successful generation of ITGB6-ko CCA cell clones with decreased migration and invasion and downregulation of PODXL2, suggesting the utility of integrin ß6 as a possible therapeutic target or diagnostic marker candidate.


Assuntos
Moléculas de Adesão Celular/metabolismo , Movimento Celular , Colangiocarcinoma/patologia , Técnicas de Inativação de Genes , Cadeias beta de Integrinas/genética , Sialoglicoproteínas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Ligação ao Cálcio/metabolismo , Moléculas de Adesão Celular/genética , Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular/genética , Colangiocarcinoma/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Cadeias beta de Integrinas/metabolismo , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Proteínas de Neoplasias/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sialoglicoproteínas/genética , Ensaio Tumoral de Célula-Tronco , Regulação para Cima/genética
4.
Br J Anaesth ; 127(3): 447-457, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34266661

RESUMO

BACKGROUND: Infant anaesthesia causes acute brain cell apoptosis, and later in life cognitive deficits and behavioural alterations, in non-human primates (NHPs). Various brain injuries and neurodegenerative conditions are characterised by chronic astrocyte activation (astrogliosis). Glial fibrillary acidic protein (GFAP), an astrocyte-specific protein, increases during astrogliosis and remains elevated after an injury. Whether infant anaesthesia is associated with a sustained increase in GFAP is unknown. We hypothesised that GFAP is increased in specific brain areas of NHPs 2 yr after infant anaesthesia, consistent with prior injury. METHODS: Eight 6-day-old NHPs per group were exposed to 5 h isoflurane once (1×) or three times (3×), or to room air as a control (Ctr). Two years after exposure, their brains were assessed for GFAP density changes in the primary visual cortex (V1), perirhinal cortex (PRC), hippocampal subiculum, amygdala, and orbitofrontal cortex (OFC). We also assessed concomitant microglia activation and hippocampal neurogenesis. RESULTS: Compared with controls, GFAP densities in V1 were increased in exposed groups (Ctr: 0.208 [0.085-0.427], 1×: 0.313 [0.108-0.533], 3×: 0.389 [0.262-0.652]), whereas the density of activated microglia was unchanged. In addition, GFAP densities were increased in the 3× group in the PRC and the subiculum, and in both exposure groups in the amygdala, but there was no increase in the OFC. There were no differences in hippocampal neurogenesis among groups. CONCLUSIONS: Two years after infant anaesthesia, NHPs show increased GFAP without concomitant microglia activation in specific brain areas. These long-lasting structural changes in the brain caused by infant anaesthesia exposure may be associated with functional alterations at this age.


Assuntos
Anestesia por Inalação/efeitos adversos , Anestésicos Inalatórios/toxicidade , Encéfalo/efeitos dos fármacos , Gliose/induzido quimicamente , Isoflurano/toxicidade , Microglia/efeitos dos fármacos , Administração por Inalação , Fatores Etários , Anestésicos Inalatórios/administração & dosagem , Animais , Animais Recém-Nascidos , Apoptose/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação ao Cálcio/metabolismo , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Gliose/metabolismo , Gliose/patologia , Isoflurano/administração & dosagem , Macaca mulatta , Masculino , Proteínas dos Microfilamentos/metabolismo , Microglia/metabolismo , Microglia/patologia , Fatores de Tempo
5.
Int J Mol Sci ; 22(14)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34299000

RESUMO

Parkinson's disease (PD) is the most common movement disorder, characterized by progressive degeneration of the nigrostriatal pathway, which consists of dopaminergic cell bodies in substantia nigra and their neuronal projections to the striatum. Moreover, PD is associated with an array of non-motor symptoms such as olfactory dysfunction, gastrointestinal dysfunction, impaired regulation of the sleep-wake cycle, anxiety, depression, and cognitive impairment. Inflammation and concomitant oxidative stress are crucial in the pathogenesis of PD. Thus, this study aimed to model PD via intrastriatal injection of the inflammagen lipopolysaccharide (LPS)to investigate if the lesion causes olfactory and motor impairments, inflammation, oxidative stress, and alteration in synaptic proteins in the olfactory bulb, striatum, and colon. Ten µg of LPS was injected unilaterally into the striatum of 27 male C57BL/6 mice, and behavioural assessment was conducted at 4 and 8 weeks post-treatment, followed by tissue collection. Intrastriatal LPS induced motor impairment in C57BL/6 mice at 8 weeks post-treatment evidenced by reduced latency time in the rotarod test. LPS also induced inflammation in the striatum characterized by increased expression of microglial marker Iba-1 and astrocytic marker GFAP, with degeneration of dopaminergic neuronal fibres (reduced tyrosine hydroxylase immunoreactivity), and reduction of synaptic proteins and DJ-1 protein. Additionally, intrastriatal LPS induced inflammation, oxidative stress and alterations in synaptic proteins within the olfactory bulb, although this did not induce a significant impairment in olfactory function. Intrastriatal LPS induced mild inflammatory changes in the distal colon, accompanied by increased protein expression of 3-nitrotyrosine-modified proteins. This model recapitulated the major features of PD such as motor impairment and degeneration of dopaminergic neuronal fibres in the striatum, as well as some pathological changes in the olfactory bulb and colon; thus, this model could be suitable for understanding clinical PD and testing neuroprotective strategies.


Assuntos
Astrócitos/metabolismo , Colo/metabolismo , Corpo Estriado/metabolismo , Neurônios Dopaminérgicos/metabolismo , Lipopolissacarídeos/metabolismo , Bulbo Olfatório/metabolismo , Doença de Parkinson/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Escala de Avaliação Comportamental , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Colo/patologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/patologia , Proteína Glial Fibrilar Ácida/metabolismo , Imuno-Histoquímica , Inflamação/metabolismo , Inflamação/patologia , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo , Microglia/metabolismo , Microglia/patologia , Bulbo Olfatório/efeitos dos fármacos , Bulbo Olfatório/patologia , Estresse Oxidativo/efeitos dos fármacos , Doença de Parkinson/patologia , Doença de Parkinson/psicologia , Proteína Desglicase DJ-1/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Substância Negra/metabolismo , Substância Negra/patologia , Tirosina 3-Mono-Oxigenase/metabolismo , alfa-Sinucleína/metabolismo
6.
Int J Mol Sci ; 22(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203170

RESUMO

Acidovorax avenae is a flagellated, pathogenic bacterium to various plant crops that has also been found in human patients with haematological malignancy, fever, and sepsis; however, the exact mechanism for infection in humans is not known. We hypothesized that the human innate immune system could be responsive to the purified flagellin isolated from A. avenae, named FLA-AA. We observed the secretion of inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-8 by treating FLA-AA to human dermal fibroblasts, as well as macrophages. This response was exclusively through TLR5, which was confirmed by using TLR5-overexpression cell line, 293/hTLR5, as well as TLR5-specific inhibitor, TH1020. We also observed the secretion of inflammatory cytokine, IL-1ß, by the activation of NLRC4 with FLA-AA. Overall, our results provide a molecular basis for the inflammatory response caused by FLA-AA in cell-based assays.


Assuntos
Comamonadaceae/química , Flagelina/farmacologia , Imunidade Inata/fisiologia , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Imunidade Inata/genética , Interleucina-18/metabolismo , Interleucina-6/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
7.
Hum Genet ; 140(9): 1367-1377, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34255152

RESUMO

Spermatozoa are polarized cells with a head and a flagellum joined together by the connecting piece. Flagellum integrity is critical for normal sperm function, and flagellum defects consistently lead to male infertility. Multiple morphological abnormalities of the flagella (MMAF) is a distinct sperm phenotype consistently leading to male infertility due to a reduced or absent sperm motility associated with severe morphological and ultrastructural flagellum defects. Despite numerous genes recently described to be recurrently associated with MMAF, more than half of the cases analyzed remain unresolved, suggesting that many yet uncharacterized gene defects account for this phenotype. By performing a retrospective exome analysis of the unsolved cases from our initial cohort of 167 infertile men with a MMAF phenotype, we identified one individual carrying a homozygous frameshift variant in CFAP206, a gene encoding a microtubule-docking adapter for radial spoke and inner dynein arm. Immunostaining experiments in the patient's sperm cells demonstrated the absence of WDR66 and RSPH1 proteins suggesting severe radial spokes and calmodulin and spoke-associated complex defects. Using the CRISPR-Cas9 technique, we generated homozygous Cfap206 knockout (KO) mice which presented with male infertility due to functional, structural and ultrastructural sperm flagellum defects associated with a very low rate of embryo development using ICSI. Overall, we showed that CFAP206 is essential for normal sperm flagellum structure and function in human and mouse and that bi-allelic mutations in CFAP206 cause male infertility in man and mouse by inducing morphological and functional defects of the sperm flagellum that may also cause ICSI failures.


Assuntos
Proteínas do Citoesqueleto , Mutação da Fase de Leitura , Homozigoto , Infertilidade Masculina , Cauda do Espermatozoide/metabolismo , Animais , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Infertilidade Masculina/genética , Infertilidade Masculina/metabolismo , Masculino , Camundongos
8.
Nutrients ; 13(6)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207745

RESUMO

It has recently been hypothesized that vitamin K could play a role in COVID-19. We aimed to test the hypotheses that low vitamin K status is a common characteristic of patients hospitalized with COVID-19 compared to population controls and that low vitamin K status predicts mortality in COVID-19 patients. In a cohort of 138 COVID-19 patients and 138 population controls, we measured plasma dephosphorylated-uncarboxylated Matrix Gla Protein (dp-ucMGP), which reflects the functional vitamin K status in peripheral tissue. Forty-three patients died within 90 days from admission. In patients, levels of dp-ucMGP differed significantly between survivors (mean 877; 95% CI: 778; 995) and non-survivors (mean 1445; 95% CI: 1148; 1820). Furthermore, levels of dp-ucMGP (pmol/L) were considerably higher in patients (mean 1022; 95% CI: 912; 1151) compared to controls (mean 509; 95% CI: 485; 540). Cox regression survival analysis showed that increasing levels of dp-ucMGP (reflecting low vitamin K status) were associated with higher mortality risk (sex- and age-adjusted hazard ratio per doubling of dp-ucMGP was 1.49, 95% CI: 1.03; 2.24). The association attenuated and became statistically insignificant after adjustment for co-morbidities (sex, age, CVD, diabetes, BMI, and eGFR adjusted hazard ratio per doubling of dp-ucMGP was 1.22, 95% CI: 0.82; 1.80). In conclusion, we found that low vitamin K status was associated with mortality in patients with COVID-19 in sex- and age-adjusted analyses, but not in analyses additionally adjusted for co-morbidities. Randomized clinical trials would be needed to clarify a potential role, if any, of vitamin K in the course of COVID-19.


Assuntos
COVID-19/mortalidade , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Hospitalização , Deficiência de Vitamina K/mortalidade , Vitamina K/sangue , Adulto , Idoso , Biomarcadores/sangue , Coagulação Sanguínea , COVID-19/complicações , COVID-19/metabolismo , Proteínas de Ligação ao Cálcio/sangue , Estudos de Coortes , Proteínas da Matriz Extracelular/sangue , Feminino , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Análise de Regressão , SARS-CoV-2 , Trombose/metabolismo , Deficiência de Vitamina K/sangue , Deficiência de Vitamina K/complicações , Adulto Jovem
9.
Anticancer Res ; 41(7): 3689-3698, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34230168

RESUMO

BACKGROUND/AIM: SPARC-related modular calcium-binding protein 2 (SMOC2), a secreted matricellular protein, is reported to be involved in cancer progression such as cell cycle, angiogenesis, and invasion. In this study, we aimed to investigate the expression of SMOC2 in various gastric lesions and assessed its prognostic value in a large cohort of gastric cancer (GC) patients. PATIENTS AND METHODS: SMOC2 mRNA levels were measured by quantitative real-time PCR using 26 matched fresh-frozen GC samples. SMOC2 protein expression was determined by immunohistochemistry on tissue microarrays including 734 GC specimens and its correlations with clinicopathological features and survival were evaluated. RESULTS: The transcription level of SMOC2 was higher in GC samples compared to normal mucosa (p=0.006). Its expression levels were associated with the intestinal stem cell (ISC) marker, LGR5, but there were no correlations with EPHB2 and OLFM4 or the candidate cancer stem cell markers CD133 and CD44. SMOC2 expression was significantly increased in the intestinal metaplasia and was further increased in gastric adenomas and early gastric cancers (EGC). In total, 34% of GCs were positive for SMOC2, and SMOC2 positivity was higher in old (p=0.001) and male (p<0.001) patients, and in well-differentiated GC (p<0.001). SMOC2 expression had a negative association with perineural invasion (p<0.001) and tumor stage (p<0.001). In survival analysis, SMOC2-positive GC patients had much better clinical outcomes in overall survival rates (p<0.001) compared to SMOC2-negative GC patients. The prognostic impact of SMOC2 remained significant both in intestinal (p<0.001) and diffuse-type GC (p<0.001). Remarkably, a multivariate analysis demonstrated SMOC2 as an independent prognostic marker [hazard ratio (HR)=0.732, p=0.045] along with venous invasion (p=0.012), tumor stage (p<0.001) and CDX2 (p=0.028). CONCLUSION: Our results suggest that SMOC2 can be a prognostic marker for better clinical outcomes in GC.


Assuntos
Biomarcadores Tumorais/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Mucosa Intestinal/metabolismo , Intestinos/patologia , Células-Tronco Neoplásicas/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Idoso , Feminino , Humanos , Mucosa Intestinal/patologia , Masculino , Estadiamento de Neoplasias/métodos , Células-Tronco Neoplásicas/patologia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
10.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200172

RESUMO

Megakaryocytes (MKs) differentiate from hematopoietic stem cells and produce platelets at the final stage of differentiation. MKs directly interact with bone cells during bone remodeling. However, whether MKs are involved in regulating bone metabolism through indirect regulatory effects on bone cells is unclear. Here, we observed increased osteoclast differentiation of bone marrow-derived macrophages (BMMs) cultured in MK-cultured conditioned medium (MK CM), suggesting that this medium contains factors secreted from MKs that affect osteoclastogenesis. To identify the MK-secreted factor, DNA microarray analysis of the human leukemia cell line K562 and MKs was performed, and S100 calcium-binding protein P (S100P) was selected as a candidate gene affecting osteoclast differentiation. S100P was more highly expressed in MKs than in K562 cells, and showed higher levels in MK CM than in K562-cultured conditioned medium. In BMMs cultured in the presence of recombinant human S100P protein, osteoclast differentiation was promoted and marker gene expression was increased. The resorption area was significantly larger in S100P protein-treated osteoclasts, demonstrating enhanced resorption activity. Overall, S100P secreted from MKs promotes osteoclast differentiation and resorption activity, suggesting that MKs indirectly regulate osteoclast differentiation and activity through the paracrine action of S100P.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Diferenciação Celular , Megacariócitos/metabolismo , Proteínas de Neoplasias/metabolismo , Osteoclastos/citologia , Osteogênese , Proteínas de Ligação ao Cálcio/genética , Células Cultivadas , Humanos , Células K562 , Megacariócitos/citologia , Proteínas de Neoplasias/genética , Osteoclastos/metabolismo
11.
FASEB J ; 35(8): e21791, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34320240

RESUMO

Chemical neurotransmission typically occurs through synapses. Previous ultrastructural examinations of monoamine neuron axon terminals often failed to identify a pre- and postsynaptic coupling, leading to the concept of "volume" transmission. Whether this results from intrinsic properties of these neurons remains undefined. We find that dopaminergic neurons in vitro establish a distinctive axonal arbor compared to glutamatergic or GABAergic neurons in both size and propensity of terminals to avoid direct contact with target neurons. While most dopaminergic varicosities are active and contain exocytosis proteins like synaptotagmin 1, only ~20% of these are synaptic. The active zone protein bassoon was found to be enriched in dopaminergic terminals that are in proximity to a target cell. Finally, we found that the proteins neurexin-1αSS4- and neuroligin-1A+B play a critical role in the formation of synapses by dopamine (DA) neurons. Our findings suggest that DA neurons are endowed with a distinctive developmental connectivity program.


Assuntos
Axônios/fisiologia , Proteínas de Ligação ao Cálcio/metabolismo , Moléculas de Adesão Celular Neuronais/metabolismo , Corpo Estriado/citologia , Dopamina/metabolismo , Neurônios Dopaminérgicos/fisiologia , Moléculas de Adesão de Célula Nervosa/metabolismo , Animais , Proteínas de Ligação ao Cálcio/genética , Moléculas de Adesão Celular Neuronais/genética , Diferenciação Celular , Técnicas de Cocultura/métodos , Dopamina/genética , Regulação da Expressão Gênica , Proteínas de Fluorescência Verde , Imuno-Histoquímica , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Moléculas de Adesão de Célula Nervosa/genética , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo
12.
Nat Commun ; 12(1): 3689, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34140486

RESUMO

Calcium imaging is a powerful tool for recording from large populations of neurons in vivo. Imaging in rhesus macaque motor cortex can enable the discovery of fundamental principles of motor cortical function and can inform the design of next generation brain-computer interfaces (BCIs). Surface two-photon imaging, however, cannot presently access somatic calcium signals of neurons from all layers of macaque motor cortex due to photon scattering. Here, we demonstrate an implant and imaging system capable of chronic, motion-stabilized two-photon imaging of neuronal calcium signals from macaques engaged in a motor task. By imaging apical dendrites, we achieved optical access to large populations of deep and superficial cortical neurons across dorsal premotor (PMd) and gyral primary motor (M1) cortices. Dendritic signals from individual neurons displayed tuning for different directions of arm movement. Combining several technical advances, we developed an optical BCI (oBCI) driven by these dendritic signalswhich successfully decoded movement direction online. By fusing two-photon functional imaging with CLARITY volumetric imaging, we verified that many imaged dendrites which contributed to oBCI decoding originated from layer 5 output neurons, including a putative Betz cell. This approach establishes new opportunities for studying motor control and designing BCIs via two photon imaging.


Assuntos
Interfaces Cérebro-Computador , Cálcio/metabolismo , Dendritos/fisiologia , Microscopia Intravital/instrumentação , Microscopia Intravital/métodos , Córtex Motor/diagnóstico por imagem , Imagem Multimodal/métodos , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Dendritos/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Implantes Experimentais , Macaca mulatta , Masculino , Modelos Neurológicos , Atividade Motora/fisiologia , Córtex Motor/fisiologia , Neurônios/fisiologia , Fótons
13.
Nature ; 595(7866): 261-265, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34135511

RESUMO

Ionotropic glutamate delta receptors 1 (GluD1) and 2 (GluD2) exhibit the molecular architecture of postsynaptic ionotropic glutamate receptors, but assemble into trans-synaptic adhesion complexes by binding to secreted cerebellins that in turn interact with presynaptic neurexins1-4. It is unclear whether neurexin-cerebellin-GluD1/2 assemblies serve an adhesive synapse-formation function or mediate trans-synaptic signalling. Here we show in hippocampal synapses, that binding of presynaptic neurexin-cerebellin complexes to postsynaptic GluD1 controls glutamate receptor activity without affecting synapse numbers. Specifically, neurexin-1-cerebellin-2 and neurexin-3-cerebellin-2 complexes differentially regulate NMDA (N-methyl-D-aspartate) receptors and AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors by activating distinct postsynaptic GluD1 effector signals. Of note, minimal GluD1 and GluD2 constructs containing only their N-terminal cerebellin-binding and C-terminal cytoplasmic domains, joined by an unrelated transmembrane region, fully control the levels of NMDA and AMPA receptors. The distinct signalling specificity of presynaptic neurexin-1 and neurexin-35,6 is encoded by their alternatively spliced splice site 4 sequences, whereas the regulatory functions of postsynaptic GluD1 are mediated by conserved cytoplasmic sequence motifs spanning 5-13 residues. Thus, GluDs are signalling molecules that regulate NMDA and AMPA receptors by an unexpected transduction mechanism that bypasses their ionotropic receptor architecture and directly converts extracellular neurexin-cerebellin signals into postsynaptic receptor responses.


Assuntos
Glutamato Desidrogenase/metabolismo , Receptores Ionotrópicos de Glutamato/metabolismo , Transdução de Sinais , Motivos de Aminoácidos , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Membrana Celular/metabolismo , Potenciais Pós-Sinápticos Excitadores , Feminino , Masculino , Camundongos , Proteínas do Tecido Nervoso/metabolismo , Moléculas de Adesão de Célula Nervosa/metabolismo , Precursores de Proteínas/metabolismo , Receptores de AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/metabolismo
14.
Genes (Basel) ; 12(5)2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34062726

RESUMO

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease that afflicts multiple organs, especially kidneys and joints. In addition to genetic predisposition, it is now evident that DNA methylation and microRNAs (miRNAs), the two major epigenetic modifications, are critically involved in the pathogenesis of SLE. DNA methylation regulates promoter accessibility and gene expression at the transcriptional level by adding a methyl group to 5' cytosine within a CpG dinucleotide. Extensive evidence now supports the importance of DNA hypomethylation in SLE etiology. miRNAs are small, non-protein coding RNAs that play a critical role in the regulation of genome expression. Various studies have identified the signature lupus-related miRNAs and their functional contribution to lupus incidence and progression. In this review, the mutual interaction between DNA methylation and miRNAs regulation in SLE is discussed. Some lupus-associated miRNAs regulate DNA methylation status by targeting the DNA methylation enzymes or methylation pathway-related proteins. On the other hand, DNA hyper- and hypo-methylation are linked with dysregulated miRNAs expression in lupus. Further, we specifically discuss the genetic imprinting Dlk1-Dio3 miRNAs that are subjected to DNA methylation regulation and are dysregulated in several autoimmune diseases, including SLE.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Epigênese Genética , Impressão Genômica , Iodeto Peroxidase/genética , Lúpus Eritematoso Sistêmico/genética , Proteínas de Membrana/genética , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Metilação de DNA , Humanos , Iodeto Peroxidase/metabolismo , Proteínas de Membrana/metabolismo , MicroRNAs/genética
15.
Nat Commun ; 12(1): 3474, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34108458

RESUMO

Sodium/proton exchanger 1 (NHE1) is an electroneutral secondary active transporter present on the plasma membrane of most mammalian cells and plays critical roles in regulating intracellular pH and volume homeostasis. Calcineurin B-homologous protein 1 (CHP1) is an obligate binding partner that promotes NHE1 biosynthetic maturation, cell surface expression and pH-sensitivity. Dysfunctions of either protein are associated with neurological disorders. Here, we elucidate structures of the human NHE1-CHP1 complex in both inward- and inhibitor (cariporide)-bound outward-facing conformations. We find that NHE1 assembles as a symmetrical homodimer, with each subunit undergoing an elevator-like conformational change during cation exchange. The cryo-EM map reveals the binding site for the NHE1 inhibitor cariporide, illustrating how inhibitors block transport activity. The CHP1 molecule differentially associates with these two conformational states of each NHE1 monomer, and this association difference probably underlies the regulation of NHE1 pH-sensitivity by CHP1.


Assuntos
Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/metabolismo , Trocador 1 de Sódio-Hidrogênio/química , Trocador 1 de Sódio-Hidrogênio/metabolismo , Sítios de Ligação , Transporte Biológico , Microscopia Crioeletrônica , Guanidinas/metabolismo , Humanos , Modelos Moleculares , Complexos Multiproteicos , Ligação Proteica , Conformação Proteica , Multimerização Proteica , Trocador 1 de Sódio-Hidrogênio/antagonistas & inibidores , Sulfonas/metabolismo
16.
Int J Mol Sci ; 22(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071277

RESUMO

Hypertrophic scars, the most common complication of burn injuries, are characterized by excessive deposition of fibroblast-derived extracellular matrix proteins. Calpain, a calcium-dependent protease, is involved in the fibroblast proliferation and extracellular matrix production observed in certain fibrotic diseases. However, its role in the formation of post-burn hypertrophic skin scars remains largely unknown. Here, calpain expression and activity were assessed in skin fibroblasts obtained directly from patients with third-degree burns, who consequently developed post-burn hypertrophic scars. Furthermore, the antifibrotic effect of calpastatin, an endogenous calpain inhibitor, was evaluated in human fibroblasts and a murine burn model. The activity, mRNA levels, and protein levels of calpain were markedly higher in fibroblasts from the burn wounds of patients than in normal cells. Selective calpain inhibition by calpastatin markedly reduced not only the proliferation of burn-wound fibroblasts but also the mRNA and protein expression of calpain, transforming growth factor-beta 1, α-smooth muscle actin, type I and type III collagens, fibronectin, and vimentin in burn-wound fibroblasts. The anti-scarring effects of calpastatin were validated using a murine burn model by molecular, histological, and visual analyses. This study demonstrates the pathological role of calpain and the antifibrotic effect of calpastatin via calpain inhibition in post-burn hypertrophic scar formation.


Assuntos
Queimaduras/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Calpaína/metabolismo , Adulto , Animais , Queimaduras/complicações , Proteínas de Ligação ao Cálcio/farmacologia , Calpaína/antagonistas & inibidores , Proliferação de Células , Cicatriz Hipertrófica/metabolismo , Colágeno Tipo III , Matriz Extracelular/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Feminino , Fibroblastos/metabolismo , Fibronectinas/metabolismo , Humanos , Hipertrofia , Masculino , Camundongos , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Pele/metabolismo , Pele/patologia , Fator de Crescimento Transformador beta1/metabolismo , Adulto Jovem
17.
FASEB J ; 35(7): e21685, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34085343

RESUMO

Leucine zipper-EF-hand containing transmembrane protein 1 (Letm1) is a mitochondrial inner membrane protein involved in Ca2+ and K+ homeostasis in mammalian cells. Here, we demonstrate that the Letm1 orthologue of Trypanosoma cruzi, the etiologic agent of Chagas disease, is important for mitochondrial Ca2+ uptake and release. The results show that both mitochondrial Ca2+ influx and efflux are reduced in TcLetm1 knockdown (TcLetm1-KD) cells and increased in TcLetm1 overexpressing cells, without alterations in the mitochondrial membrane potential. Remarkably, TcLetm1 knockdown or overexpression increases or does not affect mitochondrial Ca2+ levels in epimastigotes, respectively. TcLetm1-KD epimastigotes have reduced growth, and both overexpression and knockdown of TcLetm1 cause a defect in metacyclogenesis. TcLetm1-KD also affected mitochondrial bioenergetics. Invasion of host cells by TcLetm1-KD trypomastigotes and their intracellular replication is greatly impaired. Taken together, our findings indicate that TcLetm1 is important for Ca2+ homeostasis and cell viability in T cruzi.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Cálcio/metabolismo , Diferenciação Celular , Doença de Chagas/parasitologia , Mitocôndrias/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/crescimento & desenvolvimento , Animais , Transporte Biológico , Proteínas de Ligação ao Cálcio/antagonistas & inibidores , Proteínas de Ligação ao Cálcio/genética , Chlorocebus aethiops , Metabolismo Energético , Potencial da Membrana Mitocondrial , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/genética , Trypanosoma cruzi/metabolismo , Células Vero
18.
Res Vet Sci ; 138: 39-48, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34091228

RESUMO

Methotrexate (MTX), an antifolate drug, is widely used in chemotherapeutic protocols for metastatic and primary brain tumors and some autoimmune diseases. Its efficacy for brain tumors is limited by the high incidence of central nervous system (CNS) complications. This investigation aimed to observe the morphological effects, including astroglial and microglial responses, following systemic short-term MTX administration in adult rats. Male Wistar rats received 5 or 10 mg/kg/day of MTX by intraperitoneal route for 4 consecutive days (respectively, MTX5 and MTX10 groups) or the same volume of 0.9% saline solution (control group). On the 5th day, brain samples were collected for hematoxylin-eosin and luxol fast blue staining techniques, as well as for immunohistochemical staining for glial fibrillary acidic protein (GFAP) expression in astrocytes and Iba1 (ionized calcium binding adaptor molecule 1) for microglia in the frontal cortex, hippocampus, hypothalamus and molecular/granular layers of the cerebellum. Morphometric analyses were performed using Image Pro-Plus software. Brain levels of the proinflammatory cytokines TNF-α and IL-1ß were determined by ELISA. No signs of neuronal loss or demyelination were observed in all groups. Increased GFAP and Iba1 expression was found in all areas from the MTX groups, although it was slightly higher in the MTX10 group compared to the MTX5. Both TNF-α and IL-1ß levels were decreased in the MTX5 group compared to controls. In the MTX10 group, TNF-α decreased, although IL-1ß was increased relative to controls. MTX administration induced microglial reaction and astrogliosis in several CNS areas. In the MTX5 group, it apparently occurred in the presence of decreased proinflammatory cytokines.


Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Astrócitos/efeitos dos fármacos , Proteínas de Ligação ao Cálcio/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Gliose/fisiopatologia , Metotrexato/administração & dosagem , Proteínas dos Microfilamentos/metabolismo , Microglia/efeitos dos fármacos , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Relação Dose-Resposta a Droga , Gliose/induzido quimicamente , Gliose/patologia , Masculino , Microglia/metabolismo , Microglia/patologia , Ratos , Ratos Wistar
19.
Molecules ; 26(9)2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-34064330

RESUMO

Several genetic studies have identified a rare variant of triggering receptor expressed on myeloid cells 2 (TREM2) as a risk factor for Alzheimer's disease (AD). However, findings on the effects of TREM2 on Aß deposition are quite inconsistent in animal studies, requiring further investigation. In this study, we investigated whether elevation of TREM2 mitigates Aß pathology in TgCRND8 mice. We found that peripheral nerve injury resulted in a robust elevation of TREM2 exclusively in reactive microglia in the ipsilateral spinal cord of aged TgCRND8 mice at the age of 20 months. TREM2 expression appeared on day 1 post-injury and the upregulation was maintained for at least 28 days. Compared to the contralateral side, neither amyloid beta plaque load nor soluble Aß40 and Aß42 levels were attenuated upon TREM2 induction. We further showed direct evidence that TREM2 elevation in reactive microglia did not affect amyloid-ß pathology in plaque-bearing TgCRND8 mice by applying anti-TREM2 neutralizing antibody to selectively block TREM2. Our results question the ability of TREM2 to ameliorate established Aß pathology, discouraging future development of disease-modifying pharmacological treatments targeting TREM2 in the late stage of AD.


Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Glicoproteínas de Membrana/metabolismo , Microglia/metabolismo , Microglia/patologia , Receptores Imunológicos/metabolismo , Envelhecimento/patologia , Animais , Plexo Braquial , Proteínas de Ligação ao Cálcio/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos Transgênicos , Proteínas dos Microfilamentos/metabolismo , Nervos Periféricos/patologia , Medula Espinal/metabolismo , Medula Espinal/patologia , Corno Dorsal da Medula Espinal/patologia
20.
J Biol Chem ; 296: 100729, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33933446

RESUMO

Membrane contact sites (MCSs) formed between the endoplasmic reticulum (ER) and the plasma membrane (PM) provide a platform for nonvesicular lipid exchange. The ER-anchored tricalbins (Tcb1, Tcb2, and Tcb3) are critical tethering factors at ER-PM MCSs in yeast. Tricalbins possess a synaptotagmin-like mitochondrial-lipid-binding protein (SMP) domain and multiple Ca2+-binding C2 domains. Although tricalbins have been suggested to be involved in lipid exchange at the ER-PM MCSs, it remains unclear whether they directly mediate lipid transport. Here, using in vitro lipid transfer assays, we discovered that tricalbins are capable of transferring phospholipids between membranes. Unexpectedly, while its lipid transfer activity was markedly elevated by Ca2+, Tcb3 constitutively transferred lipids even in the absence of Ca2+. The stimulatory activity of Ca2+ on Tcb3 required intact Ca2+-binding sites on both the C2C and C2D domains of Tcb3, while Ca2+-independent lipid transport was mediated by the SMP domain that transferred lipids via direct interactions with phosphatidylserine and other negatively charged lipid molecules. These findings establish tricalbins as lipid transfer proteins, and reveal Ca2+-dependent and -independent lipid transfer activities mediated by these tricalbins, providing new insights into their mechanism in maintaining PM integrity at ER-PM MCSs.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Cálcio/metabolismo , Fosfolipídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Saccharomyces cerevisiae/citologia
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