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1.
J Anesth ; 37(1): 39-48, 2023 Feb.
Article En | MEDLINE | ID: mdl-36251094

PURPOSE: This study aimed to elucidate the effects of neuraxial analgesia on labor in women classified based on the Robson classification system. METHODS: We retrospectively reviewed the clinical data of singleton cephalic nulliparous deliveries in labor at term between January 2018 and December 2021 and compared obstetrical outcomes between deliveries with and without neuraxial analgesia in women of Robson group 1 (spontaneous labor) and group 2a (induced labor). Statistical analyses were performed using the Wilcoxon ranked-sum test, Fisher's exact test, and logistic regression model. Statistical significance was set at p < 0.05. RESULTS: We identified 2726 deliveries during the period, of which 387 deliveries (215 with analgesia and 172 without analgesia) were in Robson group 1 and 502 deliveries (258 with analgesia and 244 without analgesia) in Robson 2a. In Robson group 1 pregnancies, the cesarean section (CS) rate was higher in those who received analgesia (15%) than in those who did not (3%) (p = 0.0001). Multivariate analysis revealed that labor with analgesia was a significant risk factor for CS (p < 0.0001). Similarly, in Robson group 2a pregnancies, we observed a higher CS rate in those with analgesia than in those without analgesia (18 vs. 11%, p = 0.042). CONCLUSION: A higher CS rate was observed in deliveries with analgesia than in those without analgesia both in the Robson group 1 and group 2a pregnancies.


Analgesia, Epidural , Analgesia, Obstetrical , Analgesia , Labor, Obstetric , Pregnancy , Female , Humans , Cesarean Section , Retrospective Studies , Parity
2.
NPJ Microgravity ; 7(1): 34, 2021 Sep 17.
Article En | MEDLINE | ID: mdl-34535681

Short-chain fatty acids produced by the gut bacterial fermentation of non-digestible carbohydrates, e.g., fructo-oligosaccharide (FOS), contribute to the maintenance of skeletal muscle mass and oxidative metabolic capacity. We evaluated the effect of FOS ingestion on protein expression of soleus (Sol) and extensor digitorum longus muscles in mice exposed to microgravity (µ-g). Twelve 9-week-old male C57BL/6J mice were raised individually on the International Space Station under µ-g or artificial 1-g and fed a diet with or without FOS (n = 3/group). Regardless of FOS ingestion, the absolute wet weights of both muscles tended to decrease, and the fiber phenotype in Sol muscles shifted toward fast-twitch type following µ-g exposure. However, FOS ingestion tended to mitigate the µ-g-exposure-related decrease in oxidative metabolism and enhance glutathione redox detoxification in Sol muscles. These results indicate that FOS ingestion mildly suppresses metabolic changes and oxidative stress in antigravity Sol muscles during spaceflight.

3.
NPJ Microgravity ; 5: 16, 2019.
Article En | MEDLINE | ID: mdl-31312718

Japan Aerospace Exploration Agency (JAXA) has developed mouse habitat cage units equipped with an artificial gravity-producing centrifuge, called the Multiple Artificial-gravity Research System (MARS), that enables single housing of a mouse under artificial gravity (AG) in orbit. This is a report on a hardware evaluation. The MARS underwent improvement in water leakage under microgravity (MG), and was used in the second JAXA mouse mission to evaluate the effect of AG and diet on mouse biological system simultaneously. Twelve mice were divided into four groups of three, with each group fed a diet either with or without fructo-oligosaccharide and housed singly either at 1 g AG or MG for 30 days on the International Space Station, then safely returned to the Earth. Body weight tended to increase in AG mice and decrease in MG mice after spaceflight, but these differences were not significant. This indicates that the improved MARS may be useful in evaluating AG and dietary intervention for space flown mice.

4.
Biochem Biophys Res Commun ; 512(1): 22-28, 2019 04 23.
Article En | MEDLINE | ID: mdl-30853177

The C-terminal Ig-domain of lamin A plays critical roles in cell function via interaction with proteins, DNA, and chromatin. Mutations in this domain are known to cause various diseases including Emery-Dreifuss muscular dystrophy (EDMD) and familial partial lipodystrophy (FPLD). Here we examined the biophysical and biochemical properties of mutant Ig-domains identified in patients with EDMD and FPLD. EDMD-related mutant Ig-domain showed decreased stability to heat and denaturant. This result was also confirmed by experiments using full-length mutant lamin A, although the decrease in melting temperature was much less than that of the mutant Ig-domain alone. The unstable EDMD Ig-domain disrupted the proper assembly of lamin A, resulting in abnormal paracrystal formation and decreased viscosity. In contrast, FPLD-related mutant Ig-domains were thermally stable, although they lost DNA binding function. Alanine substitution experiments revealed a functional domain of DNA binding in the Ig-domain. Thus, the overall biophysical property of Ig-domains is closely associated with clinical phenotype.


Lamin Type A/chemistry , Muscular Dystrophy, Emery-Dreifuss/metabolism , Amino Acid Substitution , Biophysical Phenomena , DNA/chemistry , DNA/metabolism , Humans , In Vitro Techniques , Lamin Type A/genetics , Lamin Type A/metabolism , Lipodystrophy, Familial Partial/genetics , Lipodystrophy, Familial Partial/metabolism , Microscopy, Electron, Transmission , Models, Molecular , Muscular Dystrophy, Emery-Dreifuss/genetics , Mutation , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Fragments/metabolism , Protein Domains , Protein Stability , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
5.
JA Clin Rep ; 3(1): 44, 2017.
Article En | MEDLINE | ID: mdl-29457088

BACKGROUND: Pulmonary embolism (PE) resulting from venous thromboembolism is a leading cause of maternal mortality in pregnancy. In patients with massive PE and hemodynamic instability, the treatment options often considered are thrombolytics, inferior vena caval filters, or embolectomy. We report here the case of a patient with massive PE at 28 weeks' gestation, who underwent emergency pulmonary embolectomy via cardiopulmonary bypass. CASE PRESENTATION: A 35-year old primigravida with a history of massive PE at 25 weeks of gestation was referred to our hospital at 28 weeks of gestation, following treatment failure after insertion of an inferior vena cava filter and heparin administration. Emergency thrombectomy was performed, and intracardiac echography was used for intraoperative fetal heart rate monitoring. However, the patient developed hemodynamic collapse following anesthesia induction; hence, emergency cardiopulmonary bypass (CPB) was performed via median sternotomy. Thrombectomy and tricuspid valve plication were performed under cardiac arrest. After confirming postoperative hemostasis, heparin administration was resumed. At 40 weeks of gestation, labor was induced under epidural analgesia. Both mother and child were discharged with no complications. CONCLUSION: In conclusion, intracardiac echography is useful for fetal heart rate monitoring during emergency cardiac surgery in pregnancy. Careful CPB management is important to maintain uteroplacental blood flow. Although there is no consensus on the delivery methods in such cases, epidural analgesia during labor was useful in reducing cardiac load and wound traction.

6.
PLoS Curr ; 72015 Oct 29.
Article En | MEDLINE | ID: mdl-26579332

BACKGROUND: Dysferlin is a sarcolemmal protein that is defective in Miyoshi myopathy and limb-girdle muscular dystrophy type 2B, and is involved in sarcolemmal repair. Primary cultured myoblasts and myotubes established from patient muscle biopsies have been widely utilized to explore the molecular mechanism of dysferlinopathy. OBJECTIVES: The purpose of this study was to explore the possible utility of dermal fibroblasts from dysferlin-deficient patients and SJL mice as a tool for studying dysferlinopathy. METHODS: Dysferlin protein expression in fibroblasts from dysferlin-deficient patients and SJL mice was analyzed by immunoblotting and immunocytochemistry. The membrane wound-repair assay was performed on the fibroblasts using a confocal microscope equipped with a UV-laser. The membrane blebbing assay using hypotonic shock, in which normal membrane blebbing is detected only in the presence of dysferlin, was also performed using human and mouse fibroblasts. RESULTS: Mis-sense mutated dysferlin was expressed at a very low level in fibroblasts from a dysferlinopathy patient, and lower expression level of truncated dysferlin was observed in SJL mouse fibroblast. Fibroblasts from patients with dysferlinopathy and SJL mice showed attenuated membrane repair and did not form membrane blebs in response to hypoosmotic shock. Proteosomal inhibitior increased mis-sense mutated or truncated dysferlin levels, and restored membrane blebbing, however, proteosomal inhibition failed to improve levels of dysferlin with non-sense or frame-shift mutation. CONCLUSION: Fibroblasts from dysferlinopathy patients and SJL mice showed attenuated plasma membrane repair, and could be a tool for studying dysferlinopathy.

7.
PLoS One ; 9(9): e106721, 2014.
Article En | MEDLINE | ID: mdl-25198651

Defects in dystroglycan glycosylation are associated with a group of muscular dystrophies, termed dystroglycanopathies, that include Fukuyama congenital muscular dystrophy (FCMD). It is widely believed that abnormal glycosylation of dystroglycan leads to disease-causing membrane fragility. We previously generated knock-in mice carrying a founder retrotransposal insertion in fukutin, the gene responsible for FCMD, but these mice did not develop muscular dystrophy, which hindered exploring therapeutic strategies. We hypothesized that dysferlin functions may contribute to muscle cell viability in the knock-in mice; however, pathological interactions between glycosylation abnormalities and dysferlin defects remain unexplored. To investigate contributions of dysferlin deficiency to the pathology of dystroglycanopathy, we have crossed dysferlin-deficient dysferlin(sjl/sjl) mice to the fukutin-knock-in fukutin(Hp/-) and Large-deficient Largemyd/myd mice, which are phenotypically distinct models of dystroglycanopathy. The fukutin(Hp/-) mice do not show a dystrophic phenotype; however, (dysferlin(sjl/sjl): fukutin(Hp/-)) mice showed a deteriorated phenotype compared with (dysferlinsjl/sjl: fukutin(Hp/+)) mice. These data indicate that the absence of functional dysferlin in the asymptomatic fukutin(Hp/-) mice triggers disease manifestation and aggravates the dystrophic phenotype. A series of pathological analyses using double mutant mice for Large and dysferlin indicate that the protective effects of dysferlin appear diminished when the dystrophic pathology is severe and also may depend on the amount of dysferlin proteins. Together, our results show that dysferlin exerts protective effects on the fukutin(Hp/-) FCMD mouse model, and the (dysferlin(sjl/sjl): fukutin(Hp/-)) mice will be useful as a novel model for a recently proposed antisense oligonucleotide therapy for FCMD.


Dystroglycans/metabolism , Membrane Proteins/genetics , Models, Biological , Muscle Proteins/genetics , Muscle, Skeletal/pathology , Walker-Warburg Syndrome/genetics , Animals , Dysferlin , Humans , Mice , Mice, Transgenic , Walker-Warburg Syndrome/metabolism
8.
Sci Rep ; 3: 2899, 2013 Oct 11.
Article En | MEDLINE | ID: mdl-24113164

Cancer cells often develop drug resistance. In cisplatin-resistant HeLa cisR cells, fibroblast growth factor 13 (FGF13/FHF2) gene and protein expression was strongly upregulated, and intracellular platinum concentrations were kept low. When the FGF13 expression was suppressed, both the cells' resistance to platinum drugs and their ability to keep intracellular platinum low were abolished. Overexpression of FGF13 in parent cells led to greater resistance to cisplatin and reductions in the intracellular platinum concentration. These cisplatin-resistant cells also showed increased resistance to copper. In preoperative cervical cancer biopsy samples from poor prognoses patients after cisplatin chemoradiotherapy, FGF13-positive cells were detected more abundantly than in the biopsy samples from patients with good prognoses. These results suggest that FGF13 plays a pivotal role in mediating resistance to platinum drugs, possibly via a mechanism shared by platinum and copper. Our results point to FGF13 as a novel target and useful prognostic guide for cancer therapy.


Antineoplastic Agents/pharmacology , Cisplatin/pharmacology , Drug Resistance, Neoplasm/genetics , Fibroblast Growth Factors/genetics , Gene Expression Regulation, Neoplastic , Uterine Cervical Neoplasms/genetics , Adult , Alternative Splicing , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Cisplatin/therapeutic use , Female , Gene Knockdown Techniques , HeLa Cells , Humans , Middle Aged , Neoplasm Staging , RNA, Messenger/genetics , RNA, Messenger/metabolism , Treatment Outcome , Up-Regulation , Uterine Cervical Neoplasms/drug therapy , Uterine Cervical Neoplasms/mortality , Uterine Cervical Neoplasms/pathology
9.
Masui ; 62(8): 924-8, 2013 Aug.
Article Ja | MEDLINE | ID: mdl-23984565

We retrospectively examined the transversus abdominis plane (TAP) block performed in 8 infants (range, 1-115 days) from July 2010 to March 2011. Ultrasound images clearly visualized the fascial plane between the transversus abdominis and the internal oblique muscle and it was possible to confirm proper administration of local anesthetics into the plane in all patients. Complications resulting from opioid overdose were noted in two cases. One infant required reintubation. Another infant developed delayed emergence from anesthesia. We should tailor the dose of systemic opioid, considering the fact that the simultaneous administration of nerve block and systemic opioids may cause sedation and respiratory depression in young infants.


Abdominal Muscles/innervation , Nerve Block/methods , Abdominal Muscles/diagnostic imaging , Analgesics, Opioid/administration & dosage , Anesthetics, Local/administration & dosage , Humans , Infant , Infant, Newborn , Retrospective Studies , Ultrasonography
10.
Masui ; 62(4): 390-4, 2013 Apr.
Article Ja | MEDLINE | ID: mdl-23697187

BACKGROUND: Rapid and transient uterine relaxation is sometimes required for fetal distress or difficult delivery due to uterine hyperactivity during cesarean section. For its rapid onset and short duration, intravenous nitroglycerin (NTG) is commonly used for this purpose. But its suitable dose is unclear. METHODS: We evaluated the effect of NTG 200 microg on uterine relaxation in 14 parturients who required rapid uterine relaxation during cesarean delivery from October 2010 to March 2011. We assessed the softness of the uterus, maternal hemodynamic changes after NTG administration, blood loss, uterine contraction after delivery, and Apgar scores. RESULTS: Obstetricians graded the uterus as "moderately soft" in 9, and "very soft" in 5 patients, respectively. Uterine contraction after delivery was good with intravenous oxytocin or dinoprost. Blood loss was acceptable. Six patients exhibited moderate but transient hypotension, and in two of which blood pressure was immediately restored with phenylephrine 100 microg. Four patients complained of nausea and 1 patient complained of headache, but all of which were transient. Median Apgar scores at 1 and 5 minutes were 8.0 and 8.5, respectively. CONCLUSIONS: This study indicated that an intravenous administration of NTG 200 microg was effective for rapid uterine relaxation during cesarean delivery.


Cesarean Section , Nitroglycerin/administration & dosage , Uterus/drug effects , Vasodilator Agents/pharmacology , Female , Humans , Injections, Intravenous , Nitroglycerin/pharmacology , Pregnancy , Uterine Contraction/drug effects
11.
Masui ; 62(4): 406-9, 2013 Apr.
Article Ja | MEDLINE | ID: mdl-23697190

BACKGROUND: Ultrasound guided nerve block has become popular in pediatric practice. We applied this technique to infants undergoing pyloromyotomy. METHODS: We retrospectively reviewed the hospital records of infants who underwent pyloromyotomy with the aid of the ultrasound guided nerve block from July 2010 to March 2011. RESULTS: Rectus sheath block was performed in 4 infants. In one infant ilioinguinal/hypogastric nerve block was also placed for simultaneous repair of inguinal hernia. There were no complications attributable to the ultrasound guided nerve block. CONCLUSIONS: We performed ultrasound guided nerve block safely in infants undergoing pyloromyotomy.


Nerve Block/methods , Pyloric Stenosis/surgery , Abdominal Muscles/diagnostic imaging , Humans , Infant , Infant, Newborn , Retrospective Studies , Ultrasonography
12.
PLoS Curr ; 4: e5035add8caff4, 2012 Nov 05.
Article En | MEDLINE | ID: mdl-23145354

In skeletal muscle, Mitsugumin 53 (MG53), also known as muscle-specific tripartite motif 72, reportedly interacts with dysferlin to regulate membrane repair. To better understand the interactions between dysferlin and MG53, we conducted immunoprecipitation (IP) and pull-down assays. Based on IP assays, the C2A domain in dysferlin associated with MG53. MG53 reportedly exists as a monomer, a homodimer, or an oligomer, depending on the redox state. Based on pull-down assays, wild-type dysferlin associated with MG53 dimers in a Ca2+-dependent manner, but MG53 oligomers associated with both wild-type and C2A-mutant dysferlin in a Ca2+-independent manner. In pull-down assays, a pathogenic missense mutation in the C2A domain (W52R-C2A) inhibited the association between dysferlin and MG53 dimers, but another missense mutation (V67D-C2A) altered the calcium sensitivity of the association between the C2A domain and MG53 dimers. In contrast to the multimers, the MG53 monomers did not interact with wild-type or C2A mutant dysferlin in pull-down assays. These results indicated that the C2A domain in dysferlin is important for the Ca2+-dependent association with MG53 dimers and that dysferlin may associate with MG53 dimers in response to the influx of Ca2+ that occurs during membrane injury. To examine the biological role of the association between dysferlin and MG53, we co-expressed EGFP-dysferlin with RFP-tagged wild-type MG53 or RFP-tagged mutant MG53 (RFP-C242A-MG53) in mouse skeletal muscle, and observed molecular behavior during sarcolemmal repair; it has been reported that the C242A-MG53 mutant forms dimers, but not oligomers. In response to membrane wounding, dysferlin accumulated at the injury site within 1 second; this dysferlin accumulation was followed by the accumulation of wild-type MG53. However, accumulation of RFP-C242A MG53 at the wounded site was impaired relative to that of RFP-wild-type MG53. Co-transfection of RFP-C242A MG53 inhibited the recruitment of dysferlin to the sarcolemmal injury site. We also examined the molecular behavior of GFP-wild-type MG53 during sarcolemmal repair in dysferlin-deficient mice which show progressive muscular dystrophy, and found that GFP-MG53 accumulated at the wound similar to wild-type mice. Our data indicate that the coordination between dysferlin and MG53 plays an important role in efficient sarcolemmal repair.

13.
Clin Exp Metastasis ; 29(4): 327-38, 2012 Apr.
Article En | MEDLINE | ID: mdl-22274590

As malignant breast cancers progress, they acquire the ability to spread to other regions of the body, including bone and lung, but the molecular mechanism underlying the increase in metastatic potential is not fully understood. Here we studied murine 4T1E/M3 highly bone marrow metastatic breast cancer cells, which we established previously. These cells show upregulated expression of bone morphogenetic protein (BMP) 7 and BMP receptors, as well as augmented phosphorylation of Smad1/5/8. Both anchorage-independent cell growth measured in colony forming assays and cell migration measured in wound healing assays were suppressed in 4T1E/M3 cells following treatment with a neutralizing anti-BMP7 antibody or knockdown of BMP7 gene expression. In addition, metastasis of 4T1E/M3 cells to the spine and lung and intracellular levels of phosphorylated Smad1/5/8 were suppressed by knocking down BMP7. Conversely, overexpression of BMP7 in the weakly metastatic parental 4T1E cells augmented their anchorage-independent growth, migration and metastasis to spine and lung. Taken together, our results strongly suggest that augmented autocrine BMP7 signaling leads to increases in the anchorage-independent cell growth, migration and metastatic potential in our bone marrow metastatic breast cancer model.


Autocrine Communication , Bone Marrow Neoplasms/metabolism , Bone Marrow Neoplasms/secondary , Bone Morphogenetic Protein 7/metabolism , Mammary Neoplasms, Animal/metabolism , Mammary Neoplasms, Animal/pathology , Animals , Bone Marrow Neoplasms/pathology , Bone Morphogenetic Protein 7/antagonists & inhibitors , Bone Morphogenetic Protein 7/deficiency , Bone Morphogenetic Protein 7/genetics , Female , Mice , Mice, Inbred BALB C , Tumor Cells, Cultured
14.
J Cell Sci ; 123(Pt 22): 3893-900, 2010 Nov 15.
Article En | MEDLINE | ID: mdl-20980393

Mutations in LMNA, which encodes A-type nuclear lamins, cause various human diseases, including myopathy, cardiomyopathy, lipodystrophy and progeria syndrome. To date, little is known about how mutations in a single gene cause a wide variety of diseases. Here, by characterizing an antibody that specifically recognizes the phosphorylation of Ser458 of A-type lamins, we uncover findings that might contribute to our understanding of laminopathies. This antibody only reacts with nuclei in muscle biopsies from myopathy patients with mutations in the Ig-fold motif of A-type lamins. Ser458 phosphorylation is not seen in muscles from control patients or patients with any other neuromuscular diseases. In vitro analysis confirmed that only lamin A mutants associated with myopathy induce phosphorylation of Ser458, whereas lipodystrophy- or progeria-associated mutants do not. We also found that Akt1 directly phosphorylates Ser458 of lamin A with myopathy-related mutations in vitro. These results suggest that Ser458 phosphorylation of A-type lamins correlates with striated muscle laminopathies; this might be useful for the early diagnosis of LMNA-associated myopathies. We propose that disease-specific phosphorylation of A-type lamins by Akt1 contributes to myopathy caused by LMNA mutations.


Lamin Type A/metabolism , Muscular Dystrophies/metabolism , Adult , Animals , COS Cells , Child , Child, Preschool , Chlorocebus aethiops , Female , Humans , Immunohistochemistry , Lamin Type A/genetics , Male , Mice , Middle Aged , Muscular Dystrophies/genetics , Phosphorylation , Transfection
15.
J Clin Invest ; 119(9): 2623-33, 2009 Sep.
Article En | MEDLINE | ID: mdl-19726876

Caveolae are invaginations of the plasma membrane involved in many cellular processes, including clathrin-independent endocytosis, cholesterol transport, and signal transduction. They are characterized by the presence of caveolin proteins. Mutations that cause deficiency in caveolin-3, which is expressed exclusively in skeletal and cardiac muscle, have been linked to muscular dystrophy. Polymerase I and transcript release factor (PTRF; also known as cavin) is a caveolar-associated protein suggested to play an essential role in the formation of caveolae and the stabilization of caveolins. Here, we identified PTRF mutations in 5 nonconsanguineous patients who presented with both generalized lipodystrophy and muscular dystrophy. Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase levels were observed in these patients. Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all 3 caveolin family members, and reduction of caveolae structure. We generated expression constructs recapitulating the human mutations; upon overexpression in myoblasts, these mutations resulted in PTRF mislocalization and disrupted physical interaction with caveolins. Our data confirm that PTRF is essential for formation of caveolae and proper localization of caveolins in human cells and suggest that clinical features observed in the patients with PTRF mutations are associated with a secondary deficiency of caveolins.


Caveolin 3/deficiency , Lipodystrophy/genetics , Muscular Dystrophies/genetics , Mutation , RNA-Binding Proteins/genetics , Adolescent , Adult , Animals , Base Sequence , COS Cells , Cell Line , Child , Chlorocebus aethiops , DNA/genetics , DNA Mutational Analysis , Female , Heterozygote , Homozygote , Humans , INDEL Mutation , Lipodystrophy/etiology , Lipodystrophy/metabolism , Lipodystrophy/pathology , Male , Mice , Muscle, Skeletal/metabolism , Muscle, Skeletal/pathology , Muscular Dystrophies/etiology , Muscular Dystrophies/metabolism , Muscular Dystrophies/pathology , Mutagenesis, Insertional , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA-Binding Proteins/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Young Adult
16.
J Neuropathol Exp Neurol ; 68(6): 701-7, 2009 Jun.
Article En | MEDLINE | ID: mdl-19458539

Myotilin is a muscle-specific Z disk protein. Several missense mutations in the myotilin gene (MYOT) have been identified in limb girdle muscular dystrophy (LGMD), myofibrillar myopathy, and distal myopathy patients. All previously reported pathogenic MYOT mutations have been identified only in Exon 2. We sequenced MYOT in 138 patients diagnosed as having LGMD, myofibrillar myopathy, or distal myopathy, and identified a novel MYOT mutation in Exon 9 encoding the second immunoglobulin-like domain in 1 patient with clinically typical LGMD. By light microscopy, there were scattered fibers with rimmed vacuoles and myofibrillary disorganization in the patient's muscle biopsy; accumulation of Z disk proteins was observed by immunohistochemistry. Immunoblot analysis demonstrated that the amount of myotilin monomer was increased in the patient muscle, but that the myotilin homodimeric band was decreased. Functional analysis of the myotilin mutation using a yeast 2-hybrid system revealed defective homodimerization of the mutant myotilin and decreased interaction between mutant myotilin and alpha-actinin. The homodimerization defect was further demonstrated by immunoprecipitation. This is the first MYOT mutation outside of Exon 2 in an LGMD type 1A patient and the first MYOT mutation identified in the Japanese population. This mutation in the second immunoglobulin-like domain impairs myotilin dimerization and alters the binding between myotilin and alpha-actinin, which is known to be important for actin bundling.


Cytoskeletal Proteins/genetics , Exons/genetics , Muscle Proteins/genetics , Muscular Dystrophies, Limb-Girdle/genetics , Mutation, Missense/genetics , Actinin/metabolism , Animals , Arginine/genetics , COS Cells , Chlorocebus aethiops , Connectin , DNA Mutational Analysis/methods , Female , Humans , Immunoprecipitation/methods , Japan , Lysine/genetics , Male , Microfilament Proteins , Middle Aged , Molecular Sequence Data , Muscular Dystrophies, Limb-Girdle/pathology , NAD/metabolism , Protein Structure, Tertiary/genetics , Serine/metabolism , Transfection/methods , Two-Hybrid System Techniques
17.
J Clin Invest ; 118(4): 1437-49, 2008 Apr.
Article En | MEDLINE | ID: mdl-18317596

Hyperkalemic periodic paralysis (HyperKPP) produces myotonia and attacks of muscle weakness triggered by rest after exercise or by K+ ingestion. We introduced a missense substitution corresponding to a human familial HyperKPP mutation (Met1592Val) into the mouse gene encoding the skeletal muscle voltage-gated Na+ channel NaV1.4. Mice heterozygous for this mutation exhibited prominent myotonia at rest and muscle fiber-type switching to a more oxidative phenotype compared with controls. Isolated mutant extensor digitorum longus muscles were abnormally sensitive to the Na+/K+ pump inhibitor ouabain and exhibited age-dependent changes, including delayed relaxation and altered generation of tetanic force. Moreover, rapid and sustained weakness of isolated mutant muscles was induced when the extracellular K+ concentration was increased from 4 mM to 10 mM, a level observed in the muscle interstitium of humans during exercise. Mutant muscle recovered from stimulation-induced fatigue more slowly than did control muscle, and the extent of recovery was decreased in the presence of high extracellular K+ levels. These findings demonstrate that expression of the Met1592ValNa+ channel in mouse muscle is sufficient to produce important features of HyperKPP, including myotonia, K+-sensitive paralysis, and susceptibility to delayed weakness during recovery from fatigue.


Muscle, Skeletal/metabolism , Myotonia/metabolism , Myotonia/pathology , Potassium/metabolism , Sodium Channels/metabolism , Aging/physiology , Animals , Disease Progression , Electrophysiology , Gene Expression Regulation , Humans , Mice , Mice, Transgenic , Mutation/genetics , Myotonia/genetics , Oxidation-Reduction , Paralysis, Hyperkalemic Periodic/genetics , Paralysis, Hyperkalemic Periodic/metabolism , Paralysis, Hyperkalemic Periodic/pathology , Phenotype , RNA, Messenger/genetics , Sensitivity and Specificity , Sodium Channels/genetics
18.
FEBS Lett ; 582(8): 1189-96, 2008 Apr 09.
Article En | MEDLINE | ID: mdl-18325335

Affixin/beta-parvin is an integrin-linked kinase (ILK)-binding focal adhesion protein highly expressed in skeletal muscle and heart. To elucidate the possible role of affixin in skeletal muscle, we established stable C2C12 cell line expressing T7-tagged human affixin (C2C12-affixin cells). Exogenous expression of affixin promotes lamellipodium formation where affixin, ILK alphap21-activated kinase (PAK)-interactive exchange factor (PIX) and betaPIX accumulate. The association of affixin and betaPIX was confirmed by immunoprecipitation and pull down assay. In C2C12-affixin cells, an increased level of activated Rac1 but not Cdc42 was observed, and mutant betaPIX lacking guanine nucleotide exchange factor activity inhibited lamellipodium formation. These results suggest that affixin is involved in reorganization of subsarcolemmal cytoskeletal actin by activation of Rac1 through alpha and betaPIXs in skeletal muscle.


Actinin/metabolism , Cell Cycle Proteins/metabolism , Guanine Nucleotide Exchange Factors/metabolism , Muscles/metabolism , rac1 GTP-Binding Protein/metabolism , Cell Line , Fluorescent Antibody Technique , Humans , Immunoprecipitation , Muscles/cytology , Rho Guanine Nucleotide Exchange Factors
19.
Hum Mol Genet ; 16(6): 618-29, 2007 Mar 15.
Article En | MEDLINE | ID: mdl-17331981

Dysferlin is a type-II transmembrane protein and the causative gene of limb girdle muscular dystrophy type 2B and Miyoshi myopathy (LGMD2B/MM), in which specific loss of dysferlin labeling has been frequently observed. Recently, a novel mutant (L1341P) dysferlin has been shown to aggregate in the muscle of the patient. Little is known about the relationship between degradation of dysferlin and pathogenesis of LGMD2B/MM. Here, we examined the degradation of normal and mutant (L1341P) dysferlin. Wild-type (wt) dysferlin mainly localized to the ER/Golgi, associated with retrotranslocon, Sec61alpha, and VCP(p97), and was degraded by endoplasmic reticulum (ER)-associated degradation system (ERAD) composed of ubiquitin/proteasome. In contrast, mutant dysferlin spontaneously aggregated in the ER and induced eukaryotic translation initiation factor 2alpha (eIF2alpha) phosphorylation and LC3 conversion, a key step for autophagosome formation, and finally, ER stress cell death. Unlike proteasome inhibitor, E64d/pepstatin A, inhibitors of lysosomal proteases did not stimulate the accumulation of the wt-dysferlin, but stimulated aggregation of mutant dysferlin in the ER. Furthermore, deficiency of Atg5 and dephosphorylation of eIF2alpha, key molecules for LC3 conversion, also stimulated the mutant dysferlin aggregation in the ER. Rapamycin, which induces eIF2alpha phosphorylation-mediated LC3 conversion, inhibited mutant dysferlin aggregation in the ER. Thus, mutant dysferlin aggregates in the ER-stimulated autophagosome formation to engulf them via activation of ER stress-eIF2alpha phosphorylation pathway. We propose two ERAD models for dysferlin degradation, ubiquitin/proteasome ERAD(I) and autophagy/lysosome ERAD(II). Mutant dysferlin aggregates on the ER are degraded by the autophagy/lysosome ERAD(II), as an alternative to ERAD(I), when retrotranslocon/ERAD(I) system is impaired by these mutant aggregates.


Autophagy , Endoplasmic Reticulum/metabolism , Lysosomes/metabolism , Membrane Proteins/metabolism , Proteasome Endopeptidase Complex/metabolism , Animals , Cell Death , Cell Line, Tumor , Dysferlin , Embryo, Mammalian , Eukaryotic Initiation Factor-2/metabolism , Humans , Membrane Proteins/genetics , Mice , Phosphorylation , Protein Folding , Sirolimus/pharmacology , Ubiquitin/metabolism
20.
J Immunol ; 176(6): 3611-24, 2006 Mar 15.
Article En | MEDLINE | ID: mdl-16517730

Leukocyte extravasation is an important step of inflammation, in which integrins have been demonstrated to play an essential role by mediating the interaction of leukocytes with the vascular endothelium and the subendothelial extracellular matrix. Previously, we identified an integrin-linked kinase (ILK)-binding protein affixin (beta-parvin), which links initial integrin signals to rapid actin reorganization, and thus plays critical roles in fibroblast migration. In this study, we demonstrate that gamma-parvin, one of three mammalian parvin family members, is specifically expressed in several lymphoid and monocytic cell lines in a complementary manner to affixin. Like affixin, gamma-parvin directly associates with ILK through its CH2 domain and colocalizes with ILK at focal adhesions as well as the leading edge of PMA-stimulated U937 cells plated on fibronectin. The overexpression of the C-terminal fragment containing CH2 domain or the depletion of gamma-parvin by RNA interference inhibits the substrate adhesion of MCP-1-stimulated U937 cells and the spreading of PMA-stimulated U937 cells on fibronectin. Interestingly, the overexpression of the CH2 fragment or the gamma-parvin RNA interference also disrupts the asymmetric distribution of PTEN and F-actin observed at the very early stage of cell spreading, suggesting that the ILK-gamma-parvin complex is essential for the establishment of cell polarity required for leukocyte migration. Taken together with the results that gamma-parvin could form a complex with some important cytoskeletal proteins, such as alphaPIX, alpha-actinin, and paxillin as demonstrated for affixin and actopaxin (alpha-parvin), the results in this study suggest that the ILK-gamma-parvin complex is critically involved in the initial integrin signaling for leukocyte migration.


Actinin/metabolism , Leukocytes/metabolism , Protein Serine-Threonine Kinases/metabolism , Actinin/genetics , Animals , Cell Adhesion , Cell Line , Cell Survival , Chemokine CCL2/genetics , Chemokine CCL2/metabolism , Fibronectins/metabolism , Gene Deletion , Guanine Nucleotide Exchange Factors/metabolism , Humans , Leukocytes/cytology , Leukocytes/drug effects , Mutation/genetics , Phorbol Esters/pharmacology , Protein Binding , Protein Serine-Threonine Kinases/genetics , RNA Interference , Substrate Specificity
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