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1.
Nucleic Acids Res ; 51(5): e27, 2023 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-36651281

RESUMEN

Guanine (G)-rich nucleic acids are prone to assemble into four-stranded structures, so-called G-quadruplexes. Abnormal GGGGCC repeat elongations, and in particular their folding states, are associated with amyotrophic lateral sclerosis and frontotemporal dementia. Due to methodological constraints however, most studies of G quadruplex structures are restricted to in vitro conditions. Evidence of how GGGGCC repeats form into G-quadruplexes in vivo is sparse. We devised a readout strategy, exploiting the sensitivity of trans-cis isomerization of cyanine dyes to local viscosity and sterical constraints. Thereby, folding states of cyanine-labeled RNA, and in particular G-quadruplexes, can be identified in a sensitive manner. The isomerization kinetics, monitored via fluorescence blinking generated upon transitions between a fluorescent trans isomer and a non-fluorescent cis isomer, was first characterized for RNA with GGGGCC repeats in aqueous solution using fluorescence correlation spectroscopy and transient state (TRAST) monitoring. With TRAST, monitoring the isomerization kinetics from how the average fluorescence intensity varies with laser excitation modulation characteristics, we could then detect folding states of fluorescently tagged RNA introduced into live cells.


Asunto(s)
Demencia Frontotemporal , G-Cuádruplex , Humanos , Colorantes Fluorescentes , Demencia Frontotemporal/genética , Isomerismo , ARN/química
2.
Heart Vessels ; 39(4): 359-364, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37978052

RESUMEN

Acute kidney injury (AKI) frequently occurs after cardiac surgery. Recently, transcatheter aortic valve implantation (TAVI), a less invasive option for aortic stenosis (AS), has been increasingly performed, particularly in elderly patients. We retrospectively investigated and compared the incidence and risk factors of postoperative AKI in patients who underwent surgical aortic valve replacement (SAVR) and TAVI. This was a retrospective single-center study. Seven days postoperatively, data were obtained from medical records. Patients were classified into SAVR and TAVI groups based on age, according to the policy of the Japanese Circulation Society. A total of 155 patients underwent surgery for AS between January 2020 and December 2021. Variables included age, sex, risk score, preoperative left ventricular ejection fraction, hypertension, and renal dysfunction. AKI was defined in accordance with the Kidney Disease: Improving Global Outcomes criteria. A total of 33 SAVR and 79 TAVI procedures were included in this study. The incidences of AKI in the SAVR and TAVI groups were 45.5% and 43.0%, respectively. No significant differences existed between the two groups. Weight (p = 0.0392) and pre-renal dysfunction (p = 0.0308) affected the incidence of AKI in the SAVR group, whereas no such variables were identified in the TAVI group. Within the current age-based treatment selection criteria for AS, no significant difference in the incidence of AKI was observed between the two procedures.Although preoperative renal function may be associated with postoperative AKI, further studies are required to select the optimal surgical procedure for patients with renal dysfunction.


Asunto(s)
Lesión Renal Aguda , Estenosis de la Válvula Aórtica , Implantación de Prótesis de Válvulas Cardíacas , Reemplazo de la Válvula Aórtica Transcatéter , Humanos , Anciano , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Reemplazo de la Válvula Aórtica Transcatéter/métodos , Estudios Retrospectivos , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas/métodos , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular Izquierda , Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/complicaciones , Factores de Riesgo , Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/epidemiología , Lesión Renal Aguda/etiología
3.
Int J Mol Sci ; 24(6)2023 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-36982587

RESUMEN

Transactive response element DNA/RNA-binding protein 43 kDa (TDP-43) is the causative protein of amyotrophic lateral sclerosis (ALS); several ALS-associated mutants of TDP-43 have been identified. TDP-43 has several domains: an N-terminal domain, two RNA/DNA-recognition motifs, and a C-terminal intrinsically disordered region (IDR). Its structures have been partially determined, but the whole structure remains elusive. In this study, we investigate the possible end-to-end distance between the N- and C-termini of TDP-43, its alterations due to ALS-associated mutations in the IDR, and its apparent molecular shape in live cells using Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS). Furthermore, the interaction between ALS-associated TDP-43 and heteronuclear ribonucleoprotein A1 (hnRNP A1) is slightly stronger than that of wild-type TDP-43. Our findings provide insights into the structure of wild-type and ALS-associated mutants of TDP-43 in a cell.


Asunto(s)
Esclerosis Amiotrófica Lateral , Humanos , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/metabolismo , Proteínas de Unión al ADN/metabolismo , Mutación , Conformación Molecular , ARN
4.
Int J Mol Sci ; 24(9)2023 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-37176129

RESUMEN

Sensitivity to opioids varies widely among individuals. To identify potential candidate single-nucleotide polymorphisms (SNPs) that may significantly contribute to individual differences in the minimum effective concentration (MEC) of an opioid, fentanyl, we conducted a three-stage genome-wide association study (GWAS) using whole-genome genotyping arrays in 350 patients who underwent laparoscopic-assisted colectomy. To estimate the MEC of fentanyl, plasma and effect-site concentrations of fentanyl over the 24 h postoperative period were estimated with a pharmacokinetic simulation model based on initial bolus doses and subsequent patient-controlled analgesia doses of fentanyl. Plasma and effect-site MECs of fentanyl were indicated by fentanyl concentrations, estimated immediately before each patient-controlled analgesia dose. The GWAS revealed that an intergenic SNP, rs966775, that mapped to 5p13 had significant associations with the plasma MEC averaged over the 6 h postoperative period and the effect-site MEC averaged over the 12 h postoperative period. The minor G allele of rs966775 was associated with increases in these MECs of fentanyl. The nearest protein-coding gene around this SNP was DRD1, encoding the dopamine D1 receptor. In the gene-based analysis, the association was significant for the SERP2 gene in the dominant model. Our findings provide valuable information for personalized pain treatment after laparoscopic-assisted colectomy.


Asunto(s)
Fentanilo , Laparoscopía , Humanos , Estudio de Asociación del Genoma Completo , Dolor Postoperatorio/etiología , Dolor Postoperatorio/genética , Analgésicos Opioides/uso terapéutico , Polimorfismo de Nucleótido Simple , Colectomía
5.
Exp Cell Res ; 403(2): 112600, 2021 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-33862101

RESUMEN

The mechanism that mediates the interaction between the contractile ring and the plasma membrane during cytokinesis remains elusive. We previously found that ERM (Ezrin/Radixin/Moesin) proteins, which usually mediate cellular pole contraction, become over-accumulated at the cell equator and support furrow ingression upon the loss of other actin-membrane associated proteins, anillin and supervillin. In this study, we addressed the molecular basis of the exchangeability between ezrin and other actin-membrane associated proteins in mediating cortical contraction during cytokinesis. We found that depletion of anillin and supervillin caused over-accumulation of the membrane-associated FERM domain and actin-binding C-terminal domain (C-term) of ezrin at the cleavage furrow, respectively. This finding suggests that ezrin differentially shares its binding sites with these proteins on the actin cytoskeleton or inner membrane surface. Using chimeric mutants, we found that ezrin C-term, but not the FERM domain, can substitute for the corresponding anillin domains in cytokinesis and cell proliferation. On the other hand, either the membrane-associated or the actin/myosin-binding domains of anillin could not substitute for the corresponding ezrin domains in controlling cortical blebbing at the cell poles. Our results highlight specific designs of actin- or membrane-associated moieties of different actin-membrane associated proteins with limited exchangeability, which enables them to support diverse cortical activities on the shared actin-membrane interface during cytokinesis.


Asunto(s)
Actinas/genética , Citocinesis/genética , Proteínas del Citoesqueleto/genética , Proteínas de la Membrana/genética , Proteínas de Microfilamentos/genética , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/ultraestructura , Actinas/metabolismo , Sitios de Unión , Línea Celular Tumoral , Membrana Celular/química , Membrana Celular/genética , Membrana Celular/metabolismo , Proliferación Celular , Proteínas del Citoesqueleto/metabolismo , Regulación de la Expresión Génica , Genes Reporteros , Células HeLa , Humanos , Luciferasas/genética , Luciferasas/metabolismo , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Proteínas de Microfilamentos/antagonistas & inhibidores , Proteínas de Microfilamentos/metabolismo , Unión Proteica , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal
6.
J Anesth ; 36(3): 335-340, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35243545

RESUMEN

PURPOSE: To investigate the paths of thoracic epidural catheters in children, this retrospective study was performed. METHODS: We investigated 73 children aged 4 to 12 (mean ± SD 7.8 ± 2.3) years, who underwent the Nuss procedure for pectus excavatum repair under combined general and epidural anesthesia over a 5-year period at Tokyo Metropolitan Police Hospital. Following induction of general anesthesia, we inserted a radiopaque epidural catheter via the T5/6 or T6/7 interspace and advanced for 5 cm cephalad in the thoracic epidural space. We evaluated the paths of the epidural catheters on plain chest radiographs after surgery. RESULTS: The median level for the catheter tip location was T3 (range C6-T7), while the median number of vertebrae crossed by the catheter tips was 2.5. In most children, the catheters advanced straight for the first 2-3 cm (1-1.5 vertebrae) in the thoracic epidural space. However, they continued to advance straight in only 25 children, while they exhibited curved or coiled paths in the remaining 48. The catheter tips were located at higher levels in children with straight epidural catheter paths [median (range) T2 (C6-T4)] than in those with curved or coiled paths after the initial 2-3 cm [median (range) T4 (T2-T7)] (p < 0.0001). CONCLUSIONS: Our findings indicate that the course of epidural catheters in children is unpredictable after the first 2-3 cm in the thoracic epidural space. Clinicians should be aware of such findings, although further studies are required for confirmation.


Asunto(s)
Anestesia Epidural , Tórax en Embudo , Anestesia Epidural/métodos , Cateterismo/métodos , Catéteres , Niño , Tórax en Embudo/cirugía , Humanos , Estudios Retrospectivos
7.
Biochem Biophys Res Commun ; 559: 203-209, 2021 06 25.
Artículo en Inglés | MEDLINE | ID: mdl-33951500

RESUMEN

Optineurin produces intracellular multi-functions involving autophagy, vesicular trafficking, and negative regulation of inflammation signaling through interaction with various proteins such as ATG8/LC3, Rab8, and polyubiquitin. Optineurin is a component of cytoplasmic inclusion bodies (IBs) in motor neurons from amyotrophic lateral sclerosis (ALS), and its mutation E478G, has been identified in patients with ALS. However, the mechanism by which polyubiquitin binding modulates the interaction partners of OPTN and ALS-associated IB formation is still unclear. To address this issue, we analyzed the interaction of Optineurin with Rab8 and LC3 in the absence and presence of linear polyubiquitin chains using fluorescence cross-correlation spectroscopy and IB formation efficiency of the E478G mutant of Optineurin during Rab8 depletion using fluorescence microscopy. Here, we hypothesize that linear polyubiquitin binding to Optineurin dynamically induces LC3 association and Rab8 dissociation, likely through a conformational change of Optineurin, and the dynamic conformational change may prevent the aggregate formation of mutant Optineurin.


Asunto(s)
Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Transporte de Membrana/química , Proteínas de Transporte de Membrana/metabolismo , Poliubiquitina/metabolismo , Esclerosis Amiotrófica Lateral/genética , Animales , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Proteínas de Transporte de Membrana/genética , Ratones , Modelos Biológicos , Mutación/genética , Agregado de Proteínas , Unión Proteica , Conformación Proteica , Estabilidad Proteica , Transporte de Proteínas , Proteínas de Unión al GTP rab/metabolismo
8.
Langmuir ; 37(1): 437-444, 2021 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-33351626

RESUMEN

Membranes are ubiquitous structures in cells. The effects of membranes on various functional molecules have been reported, but their behaviors under macromolecular crowding and cell-sized confinement have not fully been understood. In this study, we model an intracellular environment by crowding micrometer-sized droplets and investigate the effects of membrane properties on molecular diffusion. The molecular diffusion inside small droplets covered with a lipid layer of phosphatidylcholine (PC) becomes slower compared with that of the corresponding bulk solutions under a crowding condition of polysaccharide dextran but not of its monomer unit, glucose. The addition of a poly(ethylene glycol) conjugated lipid (PEGylated lipid) to the PC membrane significantly alters the degree of slow diffusion observed inside small droplets of concentrated dextran. Interestingly, the change is not monotonic against dextran concentration; that is, the PEGylated membrane increases and decreases the degree of slow diffusion with increasing dextran concentration. We explain the nonmonotonic alternation from the increase in effective dextran concentration and the hindered temporal adsorption of dextran to the membrane. Because diffusion alteration by adding PEGylated lipid is observed for condensed small droplets of linear polymer PEG and hydrophilic protein bovine serum albumin, the phenomenon is general for other polymer systems as well. Furthermore, our findings may facilitate the understanding of intracellular molecular behaviors based on membrane effects as well as the development of numerous applications using polymer droplets.

9.
BMC Musculoskelet Disord ; 22(1): 407, 2021 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-33941145

RESUMEN

BACKGROUND: Less experienced clinicians sometimes make misdiagnosis of hip fractures. We developed computer-aided diagnosis (CAD) system for hip fractures on plain X-rays using a deep learning model trained on a large dataset. In this study, we examined whether the accuracy of the diagnosis of hip fracture of the residents could be improved by using this system. METHODS: A deep convolutional neural network approach was used for machine learning. Pytorch 1.3 and Fast.ai 1.0 were applied as frameworks, and an EfficientNet-B4 model (a pre-trained ImageNet model) was used. We handled the 5295 X-rays from the patients with femoral neck fracture or femoral trochanteric fracture from 2009 to 2019. We excluded cases in which the bilateral hips were not included within an image range, and cases of femoral shaft fracture and periprosthetic fracture. Finally, we included 5242 AP pelvic X-rays from 4851 cases. We divided these 5242 images into two images per image, and prepared 5242 images including fracture site and 5242 images without fracture site. Thus, a total of 10,484 images were used for machine learning. The accuracy, sensitivity, specificity, F-value, and area under the curve (AUC) were assessed. Gradient-weighted class activation mapping (Grad-CAM) was used to conceptualize the basis for the diagnosis of the fracture by the deep learning algorithm. Secondly, we conducted a controlled experiment with clinicians. Thirty-one residents;young doctors within 2 years of graduation from medical school who rotate through various specialties, were tested using 300 hip fracture images that were randomly extracted from the dataset. We evaluated the diagnostic accuracy with and without the use of the CAD system for each of the 300 images. RESULTS: The accuracy, sensitivity, specificity, F-value, and AUC were 96.1, 95.2, 96.9%, 0.961, and 0.99, respectively, with the correct diagnostic basis generated by Grad-CAM. In the controlled experiment, the diagnostic accuracy of the residents significantly improved when they used the CAD system. CONCLUSIONS: We developed a newly CAD system with a deep learning algorithm from a relatively large dataset from multiple institutions. Our system achieved high diagnostic performance. Our system improved the diagnostic accuracy of residents for hip fractures. LEVEL OF EVIDENCE: Level III, Foundational evidence, before-after study. CLINICAL RELEVANCE: high.


Asunto(s)
Aprendizaje Profundo , Fracturas de Cadera , Algoritmos , Inteligencia Artificial , Fracturas de Cadera/diagnóstico por imagen , Fracturas de Cadera/epidemiología , Humanos , Redes Neurales de la Computación
10.
Anal Chem ; 91(4): 2586-2590, 2019 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-30624050

RESUMEN

Molecular crowding creates a unique environment in cells and imposes physical constraints such as the excluded volume effect, water activity, and dielectric constant that can affect the structure and function of biomolecules. It is therefore important to develop a method for quantifying the effects of molecular crowding in cells. In this study, we developed a Förster resonance energy transfer (FRET) probe based on a guanine-quadruplex (G4) DNA motif that shows distinct FRET signals in response to crowding conditions in the presence of salt and poly(ethylene glycol). FRET efficiencies varied in different solutions, reflecting the dependence of G4 stability and topology on salt concentration and water activity. In living cells, FRET signals in the nucleus were higher than those in the cytosol; the signals in membraneless nuclear compartments (i.e., nucleolus) were especially high, suggesting that a decrease in water activity is important for the crowding effect in the nucleus. Thus, the use of DNA sensors with variable structures can elucidate the local effects of molecular crowding in cells.


Asunto(s)
Núcleo Celular/metabolismo , Citoplasma/metabolismo , ADN/química , G-Cuádruplex , Animales , Carbocianinas/química , Bovinos , ADN/genética , Sondas de ADN/química , Sondas de ADN/genética , Transferencia Resonante de Energía de Fluorescencia , Colorantes Fluorescentes/química , Células HeLa , Humanos , Espacio Intracelular/metabolismo , Oligodesoxirribonucleótidos/química , Oligodesoxirribonucleótidos/genética , Polietilenglicoles/química , Potasio/química , Albúmina Sérica Bovina/química , Sodio/química
11.
Biochem Biophys Res Commun ; 509(2): 577-584, 2019 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-30600183

RESUMEN

Encapsulation of guest molecules into the hollow spaces of crystals has been applied for a variety of purposes such as structure determination, separation, and catalysis of the guest. Although host-guest studies have been developed mainly in crystals of small molecules, those of biomacromolecules have recently been applied. In those reports, a huge hollow space in the protein crystal is commonly used for encapsulation of the guest. Our previous study revealed that cylindrical hemocyanins stack inside the crystal as a linear hollow structure. The diameter of the linear hollow is approximately 110 Å, which is large enough for most proteins to pass through. In the present study, we evaluated the potential of hemocyanin crystals as a host to encapsulate biomacromolecules. Confocal microscopy revealed that hemocyanin crystals encapsulate proteins of molecular mass up to 250 kDa, i.e., 27 kDa green fluorescence protein, 105 kDa allophycocyanin, 220 kDa C-phycocyanin, and 250 kDa phycoerythrin, and DNAs up to 200-bp long, whereas 440 kDa ferritin not. Further analysis revealed that hemocyanin crystals prefer a negatively charged guest rather than a positive charge to encapsulate. Moreover, a photobleaching experiment showed that the guest does not move once entrapped. This knowledge of the host-guest study using the hollow hemocyanin crystal should be of significance for further application of hollow proteinaceous crystals as a host.


Asunto(s)
Cristalización/métodos , Decapodiformes/química , Hemocianinas/química , Animales , Proteínas Fluorescentes Verdes/química , Modelos Moleculares , Ficocianina/química , Ficoeritrina/química , Porosidad
12.
Biochem Biophys Res Commun ; 497(1): 279-284, 2018 02 26.
Artículo en Inglés | MEDLINE | ID: mdl-29438711

RESUMEN

Heat shock protein 47 kDa (HSP47), an ER-resident and collagen-specific molecular chaperone, recognizes collagenous hydrophobic amino acid sequences (Gly-Pro-Hyp) and assists in secretion of correctly folded collagen. Elevated collagen production is correlated with HSP47 expression in various diseases, including fibrosis and keloid. HSP47 knockdown ameliorates liver fibrosis by inhibiting collagen secretion, and inhibition of the interaction of HSP47 with procollagen also prevents collagen secretion. Therefore, a high-throughput system for screening of drugs capable of inhibiting the interaction between HSP47 and collagen would aid the development of novel therapies for fibrotic diseases. In this study, we established a straightforward method for rapidly and quantitatively measuring the interaction between HSP47 and collagen in solution using fluorescence correlation spectroscopy (FCS). The diffusion rate of HSP47 labeled with Alexa Fluor 488 (HSP47-AF), a green fluorescent dye, decreased upon addition of type I or III collagen, whereas that of dye-labeled protein disulfide isomerase (PDI) or bovine serum albumin (BSA) did not, indicating that specific binding of HSP47 to collagen could be detected using FCS. Using this method, we calculated the dissociation constant of the interaction between HSP47 and collagen. The binding ratio between HSP47-AF and collagen did not change in the presence of sodium chloride, confirming that the interaction was hydrophobic in nature. In addition, we observed dissociation of collagen from HSP47 at low pH and re-association after recovery to neutral pH. These observations indicate that this system is appropriate for detecting the interaction between HSP47 and collagen, and could be applied to high-throughput screening for drugs capable of suppressing and/or curing fibrosis.


Asunto(s)
Colágeno/química , Proteínas del Choque Térmico HSP47/química , Imagen Molecular/métodos , Mapeo de Interacción de Proteínas/métodos , Espectrometría de Fluorescencia/métodos , Unión Proteica , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Especificidad por Sustrato
13.
Genes Cells ; 22(6): 521-534, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28497562

RESUMEN

The mechanism and cause of motor neuronal cell death in amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disorder, are unknown; gain of function of oligomers and aggregation of misfolded proteins, including carboxyl-terminal fragments (CTFs) of TAR RNA/DNA-binding protein 43 kDa (TDP-43), have been proposed as important causative factors in the onset of ALS. We recently reported that a nuclear localization signal (NLS)-tagged 25-kDa CTF of TDP-43 (TDP25) could decrease the cell-death proportion compared with that promoted by TDP25. Here, we show oligomeric states of NLS-TDP25 and its detailed localization property using super-resolution fluorescence microscopy, FRET, fluorescence recovery after photobleaching, and fluorescence correlation spectroscopy analysis. NLS-TDP25 efficiently formed a nucleolar cap structure via RNA binding in the presence of actinomycin D, but TDP25 did not. Although cytoplasmic inclusion bodies including TDP25 had a disordered and immobile structure, NLS-TDP25 in the nucleolus was ordered and dynamic. In the diffuse state, TDP25 formed fewer oligomers and interacted with the molecular chaperone, HSP70; however, NLS-TDP25 formed oligomers. These results suggested that NLS-tagged TDP25 can change its structure to use ordered oligomeric but nontoxic state. Moreover, the structure of ordered oligomers as well as nuclear sequestration may be important in mediating cytotoxicity in ALS pathology.


Asunto(s)
Esclerosis Amiotrófica Lateral/metabolismo , Núcleo Celular/metabolismo , Proteínas de Unión al ADN/metabolismo , Señales de Localización Nuclear/metabolismo , Fragmentos de Péptidos/metabolismo , Animales , Muerte Celular , Núcleo Celular/genética , Proteínas de Unión al ADN/química , Transferencia Resonante de Energía de Fluorescencia , Ratones
14.
Int J Mol Sci ; 19(4)2018 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-29570669

RESUMEN

Neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease, Parkinson's disease, and Huntington's disease, are devastating proteinopathies with misfolded protein aggregates accumulating in neuronal cells. Inclusion bodies of protein aggregates are frequently observed in the neuronal cells of patients. Investigation of the underlying causes of neurodegeneration requires the establishment and selection of appropriate methodologies for detailed investigation of the state and conformation of protein aggregates. In the current review, we present an overview of the principles and application of several methodologies used for the elucidation of protein aggregation, specifically ones based on determination of fluctuations of fluorescence. The discussed methods include fluorescence correlation spectroscopy (FCS), imaging FCS, image correlation spectroscopy (ICS), photobleaching ICS (pbICS), number and brightness (N&B) analysis, super-resolution optical fluctuation imaging (SOFI), and transient state (TRAST) monitoring spectroscopy. Some of these methodologies are classical protein aggregation analyses, while others are not yet widely used. Collectively, the methods presented here should help the future development of research not only into protein aggregation but also neurodegenerative diseases.


Asunto(s)
Amiloide/química , Proteínas/química , Fluorescencia , Humanos , Pliegue de Proteína , Espectrometría de Fluorescencia
15.
Int J Mol Sci ; 19(2)2018 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-29415503

RESUMEN

The E. coli GroEL/GroES chaperonin complex acts as a folding cage by producing a bullet-like asymmetric complex, and GroEL exists as double rings regardless of the presence of adenosine triphosphate (ATP). Its mammalian chaperonin homolog, heat shock protein, HSP60, and co-chaperonin, HSP10, play an essential role in protein folding by capturing unfolded proteins in the HSP60/HSP10 complex. However, the structural transition in ATPase-dependent reaction cycle has remained unclear. We found nucleotide-dependent association and dissociation of the HSP60/HSP10 complex using various analytical techniques under near physiological conditions. Our results showed that HSP60 exist as a significant number of double-ring complexes (football- and bullet-type complexes) and a small number of single-ring complexes in the presence of ATP and HSP10. HSP10 binds to HSP60 in the presence of ATP, which increased the HSP60 double-ring formation. After ATP is hydrolyzed to Adenosine diphosphate (ADP), HSP60 released the HSP10 and the dissociation of the double-ring to single-rings occurred. These results indicated that HSP60/HSP10 undergoes an ATP-dependent transition between the single- and double-rings in their system that is highly distinctive from the GroEL/GroES system particularly in the manner of complex formation and the roles of ATP binding and hydrolysis in the reaction cycle.


Asunto(s)
Chaperonina 60/química , Chaperonina 60/metabolismo , Fenómenos Químicos , Adenosina Trifosfato/química , Adenosina Trifosfato/metabolismo , Animales , Chaperonina 10/química , Chaperonina 10/metabolismo , Humanos , Chaperonas Moleculares/química , Chaperonas Moleculares/metabolismo , Estructura Molecular , Complejos Multiproteicos/química , Complejos Multiproteicos/metabolismo , Complejos Multiproteicos/ultraestructura , Unión Proteica
16.
Biochem Biophys Res Commun ; 463(3): 401-6, 2015 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-26032495

RESUMEN

Classical nuclear localization signal (NLS) sequences have been used for artificial localization of green fluorescent protein (GFP) in the nucleus as a positioning marker or for measurement of the nuclear-cytoplasmic shuttling rate in living cells. However, the detailed mechanism of nuclear retention of GFP-NLS remains unclear. Here, we show that a candidate mechanism for the strong nuclear retention of GFP-NLS is via the RNA-binding ability of the NLS sequence. GFP tagged with a classical NLS derived from Simian virus 40 (GFP-NLS(SV40)) localized not only in the nucleoplasm, but also to the nucleolus, the nuclear subdomain in which ribosome biogenesis takes place. GFP-NLS(SV40) in the nucleolus was mobile, and intriguingly, the diffusion coefficient, which indicates the speed of diffusing molecules, was 1.5-fold slower than in the nucleoplasm. Fluorescence correlation spectroscopy (FCS) analysis showed that GFP-NLS(SV40) formed oligomers via RNA binding, the estimated molecular weight of which was larger than the limit for passive nuclear export into the cytoplasm. These findings suggest that the nuclear localization of GFP-NLS(SV40) likely results from oligomerization mediated via RNA binding. The analytical technique used here can be applied for elucidating the details of other nuclear localization mechanisms, including those of several types of nuclear proteins. In addition, GFP-NLS(SV40) can be used as an excellent marker for studying both the nucleoplasm and nucleolus in living cells.


Asunto(s)
Núcleo Celular/metabolismo , Proteínas Fluorescentes Verdes/análisis , Señales de Localización Nuclear/análisis , ARN/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Núcleo Celular/ultraestructura , Citoplasma/metabolismo , Citoplasma/ultraestructura , Recuperación de Fluorescencia tras Fotoblanqueo , Proteínas Fluorescentes Verdes/metabolismo , Ratones , Datos de Secuencia Molecular , Señales de Localización Nuclear/metabolismo , Espectrometría de Fluorescencia
17.
Genes Cells ; 19(3): 209-24, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24450587

RESUMEN

A hallmark of protein conformational disease, exemplified by neurodegenerative disorders, is the expression of misfolded and aggregated proteins. The relationship between protein aggregation and cellular toxicity is complex, and various models of experimental pathophysiology have often yielded conflicting or controversial results. In this study, we examined the biophysical properties of amyotrophic lateral sclerosis (ALS)-linked mutations of Cu/Zn superoxide dismutase 1 (SOD1) expressed in human tissue culture cells. Fluorescence correlation spectroscopy (FCS) and Förster resonance energy transfer (FRET) analyses revealed that changes in proteasome activity affected both the expression of FCS- and FRET-detected oligomers and cellular toxicity. Under normal conditions, highly aggregation-prone mutant SOD1 exhibited very little toxicity. However, when the activity of the proteasome was transiently inhibited, only upon recovery did we observe the appearance of ordered soluble oligomers, which were closely correlated with cellular toxicity. These results shed light on the importance of balance in proteostasis and suggest that transient shifts of activity in the cellular machinery can alter the course of protein conformational transitions and dysregulate modulation of proteasome activity. In neurodegenerative disorders including ALS, such changes may be a risk factor for pathogenesis.


Asunto(s)
Esclerosis Amiotrófica Lateral/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Superóxido Dismutasa/metabolismo , Esclerosis Amiotrófica Lateral/genética , Células HeLa , Humanos , Mutación , Multimerización de Proteína , Superóxido Dismutasa/genética , Superóxido Dismutasa-1
18.
Int J Mol Sci ; 16(3): 6076-92, 2015 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-25785563

RESUMEN

Cellular homeostasis is maintained by several types of protein machinery, including molecular chaperones and proteolysis systems. Dysregulation of the proteome disrupts homeostasis in cells, tissues, and the organism as a whole, and has been hypothesized to cause neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD). A hallmark of neurodegenerative disorders is formation of ubiquitin-positive inclusion bodies in neurons, suggesting that the aggregation process of misfolded proteins changes during disease progression. Hence, high-throughput determination of soluble oligomers during the aggregation process, as well as the conformation of sequestered proteins in inclusion bodies, is essential for elucidation of physiological regulation mechanism and drug discovery in this field. To elucidate the interaction, accumulation, and conformation of aggregation-prone proteins, in situ spectroscopic imaging techniques, such as Förster/fluorescence resonance energy transfer (FRET), fluorescence correlation spectroscopy (FCS), and bimolecular fluorescence complementation (BiFC) have been employed. Here, we summarize recent reports in which these techniques were applied to the analysis of aggregation-prone proteins (in particular their dimerization, interactions, and conformational changes), and describe several fluorescent indicators used for real-time observation of physiological states related to proteostasis.


Asunto(s)
Transferencia Resonante de Energía de Fluorescencia , Proteínas/química , Retículo Endoplásmico/metabolismo , Humanos , Proteínas Luminiscentes/química , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Enfermedades Neurodegenerativas/patología , Pliegue de Proteína , Proteínas/genética , Proteínas/metabolismo , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/genética , Superóxido Dismutasa/química , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo
19.
J Anesth ; 29(5): 803-4, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25940320

RESUMEN

A needle guide kit will be able to improve visibility on ultrasonic images. We examined the degree of stability using a SIVA guide. The SIVA guide is a needle guide kit in which the angle is not restricted, allowing the puncture to be made at any angle. We punctured the Blue Phantom™ with a high-frequency linear probe with a SIVA guide and measured the intensities of the needle at depths of 0.5, 1.0, 1.5, and 2.0 cm on the ultrasound image with Image J software. We set all punctures angles at 45 degrees from the Blue Phantom™. Six anesthesiologists with >7 years experience performed two punctures-one case was punctured with a SIVA guide and the other was punctured without a SIVA guide. Some significant differences were noted in the results between the two punctures at depths of 1.0, 1.5, and 2.0 cm. We were able to prove that the use of a needle guide kit could improve visibility on ultrasonic images.


Asunto(s)
Agujas , Punciones/métodos , Ultrasonografía Intervencional/métodos , Humanos , Programas Informáticos
20.
Masui ; 64(8): 883-7, 2015 Aug.
Artículo en Japonés | MEDLINE | ID: mdl-26442430

RESUMEN

BACKGROUND: At our hospital, intending to obtaining an approval from the Joint Commission International (JCI), we conducted a workshop on sedation for all staff physicians. METHODS: A sedation instructor authorized by the Japanese Association for Medical Simulation gave a lecture using the "practice guidelines for sedation and administration of analgesics for non-anesthesiologists", revised in 2002 by the American Society of Anesthesiologists, following which, a test using 10 true-false questions was conducted, while before and after the lecture a questionnaire survey on the sedation lecture was carried out RESULTS: Among 191 physicians attending the lecture, except for one person, 7 or more questions were answered correctly. From the questionnaires, the sedation lectures were also generally accepted favourably. In the test of understanding, the mistakes were mostly in the sections on "sedation evaluation" "intraoperative monitoring" "pharmaceutical knowledge" and "airway management methods". CONCLUSIONS: The sedation lecture in the hospital was effective.


Asunto(s)
Anestesiología/educación , Manejo de la Vía Aérea , Anestesia , Sedación Profunda , Rol del Médico , Guías de Práctica Clínica como Asunto , Encuestas y Cuestionarios
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