Clinical and mutational spectrum of Charcot-Marie-Tooth disease type 2Z caused by MORC2 variants in Japan

BACKGROUND AND PURPOSE

The microrchidia family CW-type zinc finger 2 gene (MORC2) was newly identified as a causative gene of Charcot-Marie-Tooth disease (CMT) type 2Z in 2016. We aimed to describe the clinical and mutational spectrum of patients with CMT harboring MORC2 mutations in Japan.

METHODS

We analyzed samples from 781 unrelated patients clinically diagnosed with CMT using deoxyribonucleic acid microarray or targeted resequencing by next-generation sequencing, and samples from 434 mutation-negative patients were subjected to whole-exome sequencing. We extracted MORC2 variants from these whole-exome sequencing data and classified them according to American College of Medical Genetics standards and guidelines.

RESULTS

We identified MORC2 variants in 13 patients. As the second most common causative gene of CMT type 2 after MFN2, MORC2 variants were detected in 2.7% of patients with CMT type 2. The mean age of onset was 10.3 ± 8.7 years, and the inheritance pattern was mostly sporadic (11/13 patients, 84.6%). The clinical phenotype was typically length-dependent polyneuropathy, and electrophysiological studies revealed sensory-dominant axonal neuropathy. Mental retardation was identified in 4/13 patients (30.8%). p.Arg190Trp, as a mutational hotspot, was observed in eight unrelated families. We also identified two novel probably pathogenic variants, p.Cys345Tyr and p.Ala369Val, and one novel uncertain significance variant, p.Tyr332Cys.

CONCLUSIONS

Our study is the largest report of patients harboring MORC2 variants. We revealed a clinical and mutational spectrum of Japanese patients with MORC2 variants. More attention should be paid to cognitive impairment, and the responsible mechanism requires further research for elucidation.

Clinical and mutational spectrum of Japanese patients with Charcot-Marie-Tooth disease caused by GDAP1 variants

BACKGROUND

Mutations in GDAP1 are responsible for heterogeneous clinical and electrophysiological phenotypes of Charcot-Marie-Tooth disease (CMT), with autosomal dominant or recessive inheritance pattern. The aim of this study is to identify the clinical and mutational spectrum of CMT patients with GDAP1 variants in Japan.

MATERIALS AND METHODS

From April 2007 to October 2014, using three state-of-art technologies, we conducted gene panel sequencing in a cohort of 1,030 patients with inherited peripheral neuropathies (IPNs), and 398 mutation-negative cases were further analyzed with whole-exome sequencing.

RESULTS

We identified GDAP1 variants from 10 patients clinically diagnosed with CMT. The most frequent recessive variant in our cohort (5/10), c.740C>T (p.A247V), was verified to be associated with a founder event. We also detected three novel likely pathogenic variants: c.928C>T (p.R310W) and c.546delA (p.E183Kfs*23) in Case 2 and c.376G>A (p.E126K) in Case 8. Nerve conduction study or sural nerve biopsy of all 10 patients indicated axonal type peripheral neuropathy.

CONCLUSION

We identified GDAP1 variants in approximately 1% of our cohort with IPNs, and established a founder mutation in half of these patients. Our study originally described the mutational spectrum and clinical features of GDAP1-related CMT patients in Japan.

Immunosuppression Modification by Everolimus With Minimization of Calcineurin Inhibitors Recovers Kidney Graft Function Even in Patients With Very Late Conversion and Also With Poor Graft Function

BACKGROUND

Although kidney graft survival within 5 years after transplantation is now achieved in >95% of recipients, chronic graft deterioration remains a factor limiting long-term survival. Chronic nephrotoxicity induced by calcineurin inhibitors (CNIs) is one of the major causes of chronic graft injury; thus, minimization of CNIs by administration of everolimus (EVR) is expected to relieve their toxic effects.

METHODS

Fifty-six kidney transplant recipients receiving CNI-based immunosuppression (tacrolimus, n = 34; cyclosporine, n = 22) were analyzed. The average posttransplant period at conversion was 7.4 years and no less than 3 years. Conversion of immunosuppression was accomplished by reducing CNI by 40% in dose and beginning EVR at 1 or 1.5 mg. Changes in graft function were examined, and adverse effects were evaluated.

RESULTS

Significant improvement in graft function was observed quickly after EVR administration, and it had persisted for 1 year after conversion as a 7% increase in estimated glomerular filtration rate. No obvious acute rejection was observed. Further analyses concerning "timing of EVR conversion" and "graft function at conversion" were performed. Graft function was significantly improved even in patients with late conversion at 2 to 10 years. The estimated glomerular filtration rate was significantly improved even in patients with poor function.

CONCLUSIONS

We concluded that this modification to the immunosuppressive regimen, as expected, reduced CNI nephrotoxicity. Our results showed that even patients with very late conversion or poor graft function also benefited from EVR conversion with CNI minimization.

Pathological classification of human iPSC-derived neural stem/progenitor cells towards safety assessment of transplantation therapy for CNS diseases

The risk of tumorigenicity is a hurdle for regenerative medicine using induced pluripotent stem cells (iPSCs). Although teratoma formation is readily distinguishable, the malignant transformation of iPSC derivatives has not been clearly defined due to insufficient analysis of histology and phenotype. In the present study, we evaluated the histology of neural stem/progenitor cells (NSPCs) generated from integration-free human peripheral blood mononuclear cell (PBMC)-derived iPSCs (iPSC-NSPCs) following transplantation into central nervous system (CNS) of immunodeficient mice. We found that transplanted iPSC-NSPCs produced differentiation patterns resembling those in embryonic CNS development, and that the microenvironment of the final site of migration affected their maturational stage. Genomic instability of iPSCs correlated with increased proliferation of transplants, although no carcinogenesis was evident. The histological classifications presented here may provide cues for addressing potential safety issues confronting regenerative medicine involving iPSCs.

Identification and functional activity of a staphylocoagulase type XI variant originating from staphylococcal food poisoning isolates

Staphylocoagulase, an extracellular protein secreted by Staphylococcus aureus, has been used as an epidemiological marker. At least 12 serotypes and 24 genotypes subdivided on the basis of nucleotide sequence have been reported to date. In this study, we identified a novel staphylocoagulase nucleotide sequence, coa310, from staphylococcal food poisoning isolates that had the ability to coagulate plasma, but could not be typed using the conventional method. The protein encoded by coa310 contained the six fundamental conserved domains of staphylocoagulase. The full-length nucleotide sequence of coa310 shared the highest similarity (77·5%) with that of staphylocoagulase-type (SCT) XIa. The sequence of the D1 region, which would be responsible for the determination of SCT, shared the highest similarity (91·8%) with that of SCT XIa. These results suggest that coa310 is a novel variant of SCT XI. Moreover, we demonstrated that coa310 encodes a functioning coagulase, by confirming the coagulating activity of the recombinant protein expressed from coa310. This is the first study to directly demonstrate that Coa310, a putative SCT XI, has coagulating activity. These findings may be useful for the improvement of the staphylocoagulase-typing method, including serotyping and genotyping.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to identify a novel variant of staphylocoagulase type XI based on its nucleotide sequence and to demonstrate coagulating activity in the variant using a recombinant protein. Elucidation of the variety of staphylocoagulases will provide suggestions for further improvement of the staphylocoagulase-typing method and contribute to our understanding of the epidemiologic characterization of Staphylococcus aureus.

Forced expression of PDX-1 gene makes hepatoma cells to acquire glucose-responsive insulin secretion while maintaining hepatic characteristic

Evidence shows that forced expression of the PDX1 gene converts hepatoma cells, mouse liver epithelial cells (MLECs) and HepaRG cells, into insulin—producing cells, β—cells, or islets of Langerhans. However, no reports have investigated the characteristics of mouse or human hepatocytes introduced with the PDX1 gene over prolonged observation periods. In this study, we immunohistologically and molecularly investigated the alternative processes induced by PDX1 gene introduction in mouse and human hepatocytes over prolonged observation periods using immunocytochemistry, immunofluorescence, polymerase chain reaction (PCR), Western blotting, and flow cytometry (FCM) analysis. Immunocytochemical and immunofluorescent observations showed that MLECs and HepaRG cells on 2 and 21 days after introduction of the PDX1 gene comprised cells double—positive for insulin and albumin. Additionally, they showed MAFA expression and glucose—responsive insulin secretion with glucokinase expression. However mouse embryonic fibroblasts introduced with PDX1—GFP could not acquire glucose—responsive insulin secretion and glucokinase expression. Subsequently, we hypothesized that the number of albumin—positive MLECs and HepaRG cells would decrease after introduction of PDX1 due to the conversion of MLECs and HepaRG cells into insulin—producing cells. However, FCM analysis indicated that the number of albumin—positive MLECs and HepaRG cells was not altered by the introduction of PDX1. We thought that MLECs and HepaRG cells introduced with the PDX1 gene could acquire a functional insulin secretory capacity without conversion to β—cells, or islets of Langerhans, and the acquisition could need glucokinase expression.

Wearable blood flowmeter appcessory with low-power laser Doppler signal processing for daily-life healthcare monitoring

A new appcessory for monitoring peripheral blood flow in daily life consists of a wearable laser Doppler sensor device and a cooperating smart phone application. Bluetooth Low Energy connects them wirelessly. The sensor device features ultralight weight of 15 g and an intermittent signal processing technique that reduces power consumption to only 7 mW at measurement intervals of 0.1 s. These features enable more than 24-h continuous monitoring of peripheral blood flow in daily life, which can provide valuable vital-sign information for healthcare services.

Hepatocytes buried in the cirrhotic livers of patients with biliary atresia proliferate and function in the livers of urokinase-type plasminogen activator-NOG mice

The pathogenesis of biliary atresia (BA), which leads to end-stage cirrhosis in most patients, has been thought to inflame and obstruct the intrahepatic and extrahepatic bile ducts. BA is not believed to be caused by abnormalities in parenchymal hepatocytes. However, there has been no report of a detailed analysis of hepatocytes buried in the cirrhotic livers of patients with BA. Therefore, we evaluated the proliferative potential of these hepatocytes in immunodeficient, liver-injured mice [the urokinase-type plasminogen activator (uPA) transgenic NOD/Shi-scid IL2rγnull (NOG); uPA-NOG strain]. We succeeded in isolating viable hepatocytes from the livers of patients with BA who had various degrees of fibrosis. The isolated hepatocytes were intrasplenically transplanted into the livers of uPA-NOG mice. The hepatocytes of only 3 of the 9 BA patients secreted detectable amounts of human albumin in sera when they were transplanted into mice. However, human leukocyte antigen-positive hepatocyte colonies were detected in 7 of the 9 mice with hepatocyte transplants from patients with BA. We demonstrated that hepatocytes buried in the cirrhotic livers of patients with BA retained their proliferative potential. A liver that was reconstituted with hepatocytes from patients with BA was shown to be a functioning human liver with a drug-metabolizing enzyme gene expression pattern that was representative of mature human liver and biliary function, as ascertained by fluorescent dye excretion into the bile canaliculi. These results imply that removing the primary etiology via an earlier portoenterostomy may increase the quantity of functionally intact hepatocytes remaining in a cirrhotic liver and may contribute to improved outcomes.

Novel enhanced green fluorescent protein-expressing NOG mouse for analyzing the microenvironment of xenograft tissues

The interaction between transplanted cells and host tissues is important for the growth and maintenance of transplanted cells. To analyze the mechanisms of these interactions, a systemic fluorescent protein-expressing mouse is a useful recipient. In this study, we generated a novel NOG strain, which strongly expresses enhanced green fluorescent protein (EGFP; PgkEGFP-NOG), especially in the liver, kidney, gastrointestinal tract, and testis. Because the host tissues expressed EGFP, xenotransplanted human cancer cells were clearly identified as EGFP-negative colonies in PgkEGFP-NOG mice. Immunohistochemical analysis revealed that EGFP-expressing stromal tissues formed a complicated tumor microenvironment within xenograft tissues. Moreover, a similar microenvironment was observed in human iPS cell-derived teratomas. Collectively, these results indicated that a suitable microenvironment is essential for the growth and maintenance of xenotransplanted cells and that PgkEGFP-NOG mice represent a useful animal model for analyzing the mechanisms of microenvironment formation.

Sicca syndrome in patients infected with human immunodeficiency virus-1

Abstract We investigated human immunodeficiency virus-1 (HIV-1)-associated sicca syndrome. The average saliva production in HIV-infected patients was 15.9 ± 6.3 ml, and the average tear production was 9.8 ± 4.5 mm. In particular, 6 patients (42.9%) showed a significant decrease in tear production. This sicca syndrome mimicked autoimmune Sjögren's syndrome (SS) because of the presence of dry eye, dry mouth, hyperamylasemia, and hypergammaglobulinemia; however, no antinuclear antibodies, anti-SS-A, or anti-SS-B were detected in sera from HIV-1-infected patients. In addition, no relationship was observed between saliva and tear production and CD4, HIV-RNA. Hepatitis C virus (HCV) and human T-lymphotrophic virus (HTLV-1) are considered to be possible causative agents of SS. However, coinfection with HCV did not affect the decrease of saliva and tear production, and only one patient was coinfected with HTLV-1. Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are also potential causative agents of SS, and they are sometimes detected in the saliva of HIV-1-infected patients. However, the detection of EBV and CMV in the saliva was not related to the decrease in saliva production. Furthermore, HIV therapy (highly active anti-retroviral therapy; HAART) did not affect the state of sicca syndrome. The pathogenesis of sicca syndrome in HIV-1-infected patients is not clear, but we did find some infiltration of CD8 lymphocytes in salivary gland biopsy. Usually, CD8 lymphocytosis is found in peripheral blood in HIV-infected patients. Diffuse infiltrative lymphocytosis syndrome by predominant CD8 lymphocytes is occasionally found in HIV-infected patients. Such CD8 infiltration may induce the destruction of both the salivary and lacrimal glands.

Variable alteration of regional tissue oxygen pressure in rat hippocampus by acute swimming exercise

One of the events in the brain is an increasing cerebral blood flow during exercise. The tissue oxygen level may be increased because blood flow correlates with tissue oxygen level. However, it is little known whether the tissue oxygen pressure in hippocampal region (Hip-pO2) will be affected by exercise.

AIMS

The aim of this study is to examine Hip-pO2 levels in the hippocampus and its changes during exercise.

MAIN METHODS

We applied improved Clark-type electrodes to measure Hip-pO2 level in the hippocampus of rats that were subjected to three groups, 2h swimming without weights (low intensity, n=6), 2h swimming with a 5 g weight (moderate intensity, n=6), and 2h swimming with a 10 g weight (high intensity, n=6).

KEY FINDINGS

Exercise affected the Hip-pO2 level, the responses varied with the exercise intensity and duration. Interestingly during and after the Low intensity swimming the Hip-pO2 level showed long lasting enhancement (10-20% above resting level). But the moderate and high intensity swimming increased Hip-pO2 level at the start of the swimming (50%, P<0.05 and slightly above resting level, respectively, at 10 min of 2h swimming) and then began to decrease (at 120 min and 10 min of 2h swimming, respectively), and suppressed the Hip-pO2 levels during post exercise resting period (2h) (85-95% of resting level, NS and 60-70% of resting level P<0.05, respectively).

SIGNIFICANCE

We propose that exercise-induced hippocampal hyper/hypo oxygen condition may participate in beneficial exercise effects on brain function.

The human hepatic cell line HepaRG as a possible cell source for the generation of humanized liver TK-NOG mice

Humanized-liver mice, in which the liver has been repopulated with human hepatocytes, have been used to study aspects of human liver physiology such as drug metabolism, toxicology and hepatitis infection. However, the procurement of human hepatocytes is a major problem in producing humanized-liver mice because of the finite nature of the patient-derived resource.

In order to overcome this limitation, the human hepatic cell line HepaRG® were evaluated as promising donor cells for liver reconstitution in the TK-NOG mouse model.

We demonstrate that, in vivo, transplanted confluent culture or differentiated HepaRG® cells proliferated and differentiated toward both hepatocyte-like and biliary-like cells within the recipient liver. In contrast, proliferative HepaRG® cells could engraft TK-NOG mouse liver but could differentiate only toward biliary-like cells. The differentiation to hepatocyte-like cells was characterized by the detection of human albumin in the recipient mouse serum and was confirmed by immunohistochemical staining for human leukocyte antigen, human albumin, cytochrome P450 3A4, and multidrug resistance-associated protein 2. Biliary-like cells were characterized by positive staining for cytokeratin-19.

These results indicated that the differentiated HepaRG® cells are a possible cell source for generating humanized-liver mice, which are a useful model for in vivo studies of liver physiology.

Albumin gene targeting in human embryonic stem cells and induced pluripotent stem cells with helper-dependent adenoviral vector to monitor hepatic differentiation

Although progresses in developing differentiation procedures have been achieved, it remains challenging to generate hES/iPS cell-derived mature hepatocytes. We performed knock-in of a monomeric Kusabira orange (mKO1) cassette in the albumin (ALB) gene, in human embryonic stem (hES) cells and induced pluripotent stem (hiPS) cells, with the use of the helper-dependent adenovirus vector (HDAdV). Upon induction into the hepatic lineages, these knock-in hES/iPS cells differentiated into cells that displayed several known hepatic functions. The mKO1 knock-in (ALB/mKo1) hES/hiPS cells were used to visualize hepatic differentiation in vitro. mKO1 reporter expression recapitulated endogenous ALB transcriptional activity. ALB/mKo1 [Hi] population isolated by flow cytometry was confirmed to be enriched with ALB mRNA. Expression profile analyses revealed that characteristic hepatocyte genes and genes related to drug metabolism and many aspects of liver function were highly enriched in the ALB/mKo1 [Hi] population. Our data demonstrate that ALB/mKo1 knock-in hES/iPS cells are valuable resources for monitoring in vitro hepatic differentiation, isolation and analyses of hES and hiPS cells-derived hepatic cells that actively transcribing ALB. These knock-in hES/iPS cell lines could provide further insights into the mechanism of hepatic differentiation and molecular signatures of the hepatic cells derived from hES/iPS cells.

Facilitative effect of serotonin(1A) receptor agonists on cognition in patients with schizophrenia

Disturbances of cognitive function are considered to largely affect the outcome in patients with schizophrenia. There is much attention to the role of psychotropic compounds acting on serotonin (5-HT) receptors in ameliorating cognitive deficits of the disease. Among the 5-HT receptor subtypes, the 5-HT(1A) receptor is attracting particular interests as a potential target for enhancing cognition, based on preclinical and clinical evidence. The neural network underlying the ability of 5-HT(1A) agonists to treat cognitive impairments of schizophrenia likely includes dopamine, glutamate, and gamma-aminobutyric acid neurons. Recent advances of electrophysiological measures, such as event-related potentials, have provided insights into facilitative effects on cognition of some atypical antipsychotic drugs or related compounds acting directly or indirectly on 5-HT(1A) receptors. These considerations are expected to promote the development of novel therapeutics for the betterment of functional outcome in people suffering from schizophrenia.

Efficacy and safety of bipolar electrode grasping forceps for laparoscopic myomectomy in uterine cervical myoma

INTRODUCTION

Myomectomy for cervical myoma is problematic because cervical myomas are very close to neighboring structures, such as the ureters, uterine artery, bladder and rectum. There are a few reports on laparoscopic myomectomy for cervical myomas to avoid blood loss, such as occlusion of iliac arteries and clipping of the uterine artery. We evaluated the efficacy and safety of bipolar electrode grasping forceps for laparoscopic myomectomy in uterine cervical myoma.

METHODS

From November 2006 to May 2009, eight women with uterine cervical myoma underwent laparoscopic myomectomy. We employed electrode grasping forceps with a combination of two tenaculums for separating and securing hemostatsis.

RESULTS

Seven of eight cases were successfully treated by laparoscopic myomectomy, but one patient, with a large 900-g myoma was converted to the laparotomy as a result of blood loss (1800 mL). Among the other seven cases, the average weight of the myoma was 132 g (range, 16-310 g) and the operating time was 176 min. (range, 125-255 min). No complications occurred. Of the four cases who wanted to become pregnant postoperatively, two became pregnant and delivered by Caesarean section.

CONCLUSION

These findings indicate that bipolar electrode grasping forceps using two tenaculums for traction of the myoma are useful for laparoscopic myomectomy in cervical myomas.

In vitro models of pancreatic differentiation using embryonic stem or induced pluripotent stem cells

Embryonic stem (ES) cells or induced pluripotent stem (iPS) cells are expected as a surrogate cell source for regenerative medicine. Many researchers have reported the differentiation method of insulin-expressing pancreatic β cells from ES or iPS cells. However, the detailed molecular mechanisms underlying the differentiation of ES or iPS cells into pancreatic lineages are still unclear. We have established a feeder cell-based differentiation system into pancreatic progenitor cells, and revealed the signaling pathways that are involved in the differentiation of ES cells into mesendoderm, endoderm and pancreatic progenitor cells. Recently, we demonstrated that the extracellular environment, particularly the laminin-integrin signaling and heparan sulfate proteoglycan, is important for the regionalization of definitive endoderm cells into pancreatic lineages. These results provide new insights for the differentiation mechanism of pancreatic cell lineages.

The correlation between the telomeric parameters and the clinical laboratory data in the patients with brain infarct and metabolic disorders

OBJECTIVE

To elucidate the correlation between the telomere length and subtelomeric methylated status in peripheral leukocytes and the laboratory data of inpatients with brain infarction and metabolic disorders. This is the first report describing a link between routine clinical laboratory data and genomic aging.

DESIGN

Cross-sectional population-based study.

SETTING

Chronic disease ward of Kyushu University Hospital at Beppu in Japan.

PARTICIPANTS

Inpatients with brain infarction and metabolic disorders.

MEASUREMENTS

The laboratory data of male patients were collected and the telomeric parameters in their peripheral leukocytes were determined by a Southern blot analysis with methylation-sensitive and insensitive isoschizomers. Any correlations between the laboratory data and the telomeric parameters were assessed.

RESULTS

The patients revealed a significant correlation among the fasting blood sugar, HbA1c, serum creatinine and urea nitrogen levels with the mean telomere length, expression of long telomeres ( > 9.4 kb), or the subtelomeric hypermethylation status of long telomeres.

CONCLUSION

Our results suggested that the hyperglycemia and renal function of patients with metabolic disorders correlated positively with the aging-associated telomeric changes.