Utilizing noncatalytic ACE2 protein mutant as a competitive inhibitor to treat SARS-CoV-2 infection

Introduction

Angiotensin converting-enzyme 2 (ACE2) is an enzyme catalyzing the conversion of angiotensin 2 into angiotensin 1-7. ACE2 also serves as the receptor of several coronaviruses, including SARS-CoV-1 and SARS-CoV-2. Therefore, ACE2 could be utilized as a therapeutic target for treating these coronaviruses, ideally lacking enzymatic function.

Methods

Based on structural analysis, specific mutations were introduced to generate mutants of ACE2 and ACE2-Fc (fusion protein of ACE2 and Fc region of IgG1). The enzyme activity, binding affinity, and neutralization abilities were measured.

Results and discussion

As predicted, five mutants (AMI081, AMI082, AMI083, AMI084, AMI090) have completely depleted ACE2 enzymatic activities. More importantly, enzyme-linked receptor-ligand assay (ELRLA) and surface plasmon resonance (SPR) results showed that 2 mutants (AMI082, AMI090) maintained binding activity to the viral spike proteins of SARS-CoV-1 and SARS-CoV-2. In An in vitro neutralization experiment using a pseudovirus, SARS-CoV-2 S1 spike protein-packed lentivirus particles, was also performed, showing that AMI082 and AMI090 significantly reduced GFP transgene expression. Further, in vitro virulent neutralization assays using SARS-CoV-2 (strain name: USA-WA1/2020) showed that AMI082 and AMI090 had remarkable inhibitory effects, indicated by comparable IC50 to wildtype ACE2 (5.33 µg/mL). In addition to the direct administration of mutant proteins, an alternative strategy for treating COVID-19 is through AAV delivery to achieve long-lasting effects. Therefore, AAV5 encoding AMI082 and AMI090 were packaged and transgene expression was assessed. In summary, these ACE2 mutants represent a novel approach to prevent or treat COVID-19 and other viruses with the same spike protein.

Evaluation of recombinant baculovirus clearance during rAAV production in Sf9 cells using a newly developed fluorescent-TCID50 assay

Introduction

Recombinant adeno-associated virus (rAAV) vectors provide a safe and efficient means for in vivo gene delivery, although its large-scale production remains challenging. Featuring high manufacturing speed, flexible product design, and inherent safety and scalability, the baculovirus/Sf9 cell system offers a practical solution to the production of rAAV vectors in large quantities and high purity. Nonetheless, removal and inactivation of recombinant baculoviruses during downstream purification of rAAV vectors remain critical prior to clinical application.

Methods

The present study utilized a newly developed fluorescent-TCID50 (F-TCID50) assay to determine the infectious titer of recombinant baculovirus (rBV) stock after baculovirus removal and inactivation, and to evaluate the impact of various reagents and solutions on rBV infectivity.

Results and discussion

The results showed that a combination of sodium lauryl sulfate (SLS) and Triton X-100 lysis, AAVx affinity chromatography, low pH hold (pH3.0), CsCl ultracentrifugation, and NFR filtration led to effective removal and/or inactivation of recombinant baculoviruses, and achieved a log reduction value (LRV) of more than 18.9 for the entire AAV purification process. In summary, this study establishes a standard protocol for downstream baculovirus removal and inactivation and a reliable F-TCID50 assay to detect rBV infectivity, which can be widely applied in AAV manufacturing using the baculovirus system.

Systematic comparison of rAAV vectors manufactured using large-scale suspension cultures of Sf9 and HEK293 cells

Recombinant adeno-associated virus (rAAV) vectors could be manufactured by plasmid transfection into human embryonic kidney 293 (HEK293) cells or baculovirus infection of Spodoptera frugiperda (Sf9) insect cells. However, systematic comparisons between these systems using large-scale, high-quality AAV vectors are lacking. rAAV from Sf9 cells (Sf9-rAAV) at 2-50 L and HEK293 cells (HEK-rAAV) at 2-200 L scales were characterized. HEK-rAAV had ∼40-fold lower yields but ∼10-fold more host cell DNA measured by droplet digital PCR and next-generation sequencing, respectively. The electron microscope observed a lower full/empty capsid ratio in HEK-rAAV (70.8%) than Sf9-rAAV (93.2%), while dynamic light scattering and high-performance liquid chromatography analysis showed that HEK-rAAV had more aggregation. Liquid chromatography tandem mass spectrometry identified different post-translational modification profiles between Sf9-rAAV and HEK-rAAV. Furthermore, Sf9-rAAV had a higher tissue culture infectious dose/viral genome than HEK-rAAV, indicating better infectivity. Additionally, Sf9-rAAV achieved higher in vitro transgene expression, as measured by ELISA. Finally, after intravitreal dosing into a mouse laser choroidal neovascularization model, Sf9-rAAV and HEK-rAAV achieved similar efficacy. Overall, this study detected notable differences in the physiochemical characteristics of HEK-rAAV and Sf9-rAAV. However, the in vitro and in vivo biological functions of the rAAV from these systems were highly comparable. Sf9-rAAV may be preferred over HEK293-rAAV for advantages in yields, full/empty ratio, scalability, and cost.

[The correlation between burst suppression on electroencephalogram during laparoscopic surgery and emergence delirium in elderly patients]

Objective: To investigate the relationship between intraoperative electroencephalogram burst suppression (BS) and emergence delirium (ED) in elderly patients undergoing elective laparoscopic surgery under total intravenous anesthesia (TIVA). Methods: From October 2017 to September 2019, a total of 358 elderly patients who underwent elective laparoscopic surgery under TIVA at Xiangya Hospital, Central South University, were included. Patients were divided into two groups based on the confusion assessment method for the intensive care unit (CAM-ICU) assessment conducted before leaving the post-anesthesia care unit (PACU): the ED group [n=63, 46 males, 17 females, average age of (70.8±0.6) years] and the non-ED group [n=295, 220 males, 75 females, average age of (69.7±0.2) years]. Preoperative general information, intraoperative conditions, and intraoperative electroencephalogram BS status were collected. A multivariate logistic regression model was employed to identify risk factors associated with ED. Results: In the ED group, the duration of surgery, intraoperative blood loss, the burst suppression ratio (BSR)>10% lasting for more than 1 minute were (224.4±9.6) min, (240.8±33.9) ml, 36.5% (23/63), respectively, which were higher than those of the non-ED group [(204.7±3.6) min, (150.5±9.2) ml, 21.7% (64/295), all P<0.05]. Multivariate logistic regression analysis revealed that a longer duration of education was a protective factor for ED (OR=0.904, 95%CI: 0.833-0.982,P=0.016), whereas increased intraoperative blood loss (OR=1.002, 95%CI: 1.000-1.003, P=0.013) and BSR>10% lasting for more than 1 minute (OR=2.131, 95%CI: 1.004-4.524,P=0.049) were identified as risk factors for ED. Conclusion: In elderly patients undergoing laparoscopic surgery under TIVA, intraoperative electroencephalogram BS may be a risk factor for ED.

MiR-942-5p alleviates septic acute kidney injury by targeting FOXO3

OBJECTIVE

Sepsis refers to the systemic inflammatory response caused by infection. Acute kidney injury (AKI) in sepsis is very common, and there are many complicated mechanisms for the occurrence of septic AKI. This article aimed to study the role of miR-942-5p in inflammation and apoptosis of septic AKI and its potential mechanism.

MATERIALS AND METHODS

Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was performed to detect the expression of RNAs. The protein expression was detected using Western blot. The contents of inflammatory factors in the cell supernatant were detected using commercial enzyme-linked immunosorbent assay (ELISA) kits. Cell Counting Kit-8 (CCK-8) assay was utilized to compare the cell viability of each group. Terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry were used to observe cell apoptosis.

RESULTS

MiR-942-5p expression was reduced in lipopolysaccharide (LPS)-treated HK-2 cells. MiR-942-5p mimic could observably increase miR-942-5p expression. The overexpression of miR-942-5p dramatically inhibits the expression of inflammatory factors and Bax, but increase Bcl-2 expression. MiR-942-5p overexpression greatly reversed the LPS-induced decrease in viability of HK-2 cells. In addition, we observed that LPS can markedly increase the number of apoptosis, while miR-942-5p mimic can reduce it.

CONCLUSIONS

Taken together, our results demonstrated that miR-942-5p expression was reduced in the LPS-treated HK-2 cells, and miR-942-5p overexpression can inhibit LPS-induced inflammation and apoptosis of HK-2 cells via targeting FOXO3.

Influences of up-regulation of miR-126 on septic inflammation and prognosis through AKT/Rac1 signaling pathway

OBJECTIVE

To explore the influences of the up-regulation of micro ribonucleic acid (miR)-126 on septic inflammation and prognosis through the AKT/Rac1 signaling pathway.

MATERIALS AND METHODS

Human pulmonary microvascular endothelial cells (HMVECs) were cultured and transfected with miR-126 mimics. The HMVECs in the logarithmic growth phase in different groups were incubated with thrombin. The transmembrane resistivity of HMVECs was detected as the permeability via Electric Cell-substrate Impedance Sensing (ECIS) system. The endothelial cell space was observed via immunofluorescence. The mouse model of sepsis was then established and the serum was extracted to detect interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The survival curve was plotted based on the death time. The Statistical Product and Service Solutions (SPSS) 22.0 was used for statistical analysis, and p<0.05 suggested that the difference was statistically significant.

RESULTS

Thrombin could significantly increase the permeability of HMVECs, while the overexpression of miR-126 markedly inhibited the increased permeability. The overexpression of miR-126 also reduced the endothelial cell space induced by thrombin. In addition, the serum IL-6 and TNF-α levels of sepsis mice in miR-126 overexpression group were significantly decreased compared to those in the control group. Moreover, the death rate of mice exogenously expressing miR-126 was lower than that in the control group.

CONCLUSIONS

The up-regulation of miR-126 inhibited the septic inflammation and improved the prognosis of sepsis mice through the AKT/Rac1 signaling pathway.

A longitudinal study on α-synuclein in plasma neuronal exosomes as a biomarker for Parkinson's disease development and progression

BACKGROUND AND PURPOSE

The identification of reliable diagnostic and prognostic biomarkers for Parkinson's disease (PD) is urgently needed. Here, we explored the potential use of α-synuclein (α-syn) in plasma neuronal exosomes as a biomarker for early PD diagnosis and disease progression.

METHODS

This study included both cross-sectional and longitudinal designs. The subjects included 36 patients with early-stage PD, 17 patients with advanced PD, 20 patients with idiopathic rapid eye movement sleep behavior disorder and 21 healthy controls (HCs). α-syn levels were measured by electrochemiluminescence immunoassay. A subgroup of patients with early-stage PD (n = 18) participated in a follow-up examination with repeated blood collection and clinical assessments after an average of 22 months.

RESULTS

The α-syn levels in plasma neuronal exosomes were significantly higher in patients with early-stage PD compared with HCs (P = 0.007). Differences in α-syn levels between patients with idiopathic rapid eye movement sleep behavior disorder and HCs did not reach statistical significance (P = 0.08). In addition, Spearman correlation analysis revealed that neuronal exosomal α-syn concentrations were correlated with Movement Disorders Society Unified Parkinson's Disease Rating Scale III/(I + II + III) scores, Non-Motor Symptom Questionnaire scores and Sniffin' Sticks 16-item test scores of patients with PD (P < 0.05). After a mean follow-up of 22 months in patients with early-stage PD, a Cox regression analysis adjusted for age and gender showed that longitudinally increased α-syn rather than baseline α-syn levels were associated with higher risk for motor symptom progression in PD (P = 0.039).

CONCLUSIONS

Our results suggested that α-syn in plasma neuronal exosomes may serve as a biomarker to aid early diagnosis of PD and also as a prognostic marker for PD progression.

Health-Related Quality of Life in Patients Treated with Continuous Ambulatory Peritoneal Dialysis and Automated Peritoneal Dialysis in Singapore

OBJECTIVE

This study aimed to compare the health-related quality of life (HRQOL) in patients with end-stage renal disease (ESRD) treated with continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) in Singapore.

METHODS

The data used in this study were from two cross-sectional surveys of ESRD patients. HRQOL was assessed using the Kidney Disease Quality of Life (KDQOL) instrument. Socio-demographic characteristics and clinical data were collected. The physical component summary (PCS) and mental component summary (MCS) scores, kidney disease component summary (KDCS) score and its three scales (symptoms, effects, burden), and one health utility score [EuroQol 5-dimension (EQ-5D)] were calculated and compared between CAPD and APD using multivariate linear regression.

RESULTS

In total, 266 patients were included, with 145 on CAPD (mean age 60.8 years) and 121 on APD (mean age 57.4 years). After adjustment for all variables collected, APD patients had significant higher scores in PCS and KDQOL symptoms than CAPD patients, suggesting that APD was associated with better physical health and milder dialysis-related symptoms.

CONCLUSION

The HRQOL of CAPD and APD patients was largely equivalent in Singapore, but APD patients seemed to experience better physical health and be less bothered by dialysis-related symptoms.

[Clinical study of aged patients with secondary benign paroxysmal positional vertigo]

Objective: To investigate the clinical features and evaluate the efficacy of manual reduction in treatment of age patients with secondary benign paroxysmal positional vertigo (s-BPPV). Methods: Thirty-two cases of aged patients ( the s-BPPV group: including 19 cases of female and 13 males, age from 60 to 86 years old)with secondary benign paroxysmal positional vertigo from Jul. 2013 to Sep. 2015 in our hospital were retrospectively analyzed. The results were compared with 121 patients( the primary group: including 82 cases of female and 39males, aged from 60 to 86 years old)with aged primary benign paroxysmal positional vertigo(p -BPPV). All the patients were followed up for 12 months. Statistical data analysis was carried out with SPSS 19.0. Results: 20.92%(32/153)of all the observed elderly patients with BPPV was the aged s-BPPV. The sex ratio and onset age had no significant difference between the two groups(χ(2)=0.79, P>0.05; t=0.37, P>0.05). The rate of two or more semicircular canal involvement in the secondary group(21.88%) was higher than that in primary group(6.61%)(χ(2)=6.67, P<0.05). Bilateral semicircular canals were involved in 5 of the 32 cases in secondary group(15.63%) and 4 of the 121 cases in aged primary group(3.31%), The difference was significant(χ(2)=6.94, P<0.05). The effective rate after first manual reduction was 57.50%(23/40)in secondary group and 82.31%(107/130)in primary group, the difference was significant(χ(2)=10.46, P<0.05). The total effective rate were 87.50%(35/40) after more than once manual reduction in secondary group and 91.54%(119/130) in primary group, the difference was not significant(χ(2)= 0.59, P>0.05). The numbers of circulation of the first successful manual reduction management were (3.9±1.3)times in secondary group and (2.1±1.1)times in primary group, the difference was significant(t=3.15, P<0.05). The recurrence rate was 37.50%(15/40) in the secondary group and 16.15%(21/130)in primary group after during follow-up for 12 months, the difference was statistically significant(χ(2)=8.35, P<0.05). Conclusions: It's shown that the aged patients with secondary BPPV is not rare in clinical practice, sudden deafness and head trauma are frequent more than other reasons. The aged patients with secondary BPPV are prone to injury in multi-semicircular and bilateral canal compared with the primary BPPV. The effective rate after first manual reduction of secondary BPPV is lower than primary BPPV, it's needed more circulation of first success in manual reduction management. The total effective rates are not significant in two groups and recurrence rate is relatively high in secondary group.

Abstract P1-04-02: Improving immunotherapy response by epigenetic modulation

The presence of predicted neo-antigens in any given tumor is highly correlated with total somatic mutational burden of the same tumor genome. However, many potential neo-antigens are never transcribed, translated, or presented as antigens, partially because they lie in regions of the genome that are transcriptionally-repressed by cytosine methylation of promoter-CpG islands. Treatment with DNA methyltransferase inhibitors (DNMTi) can hypothetically lead to re-expression of many potential neo-antigens. Furthermore, the presence of neo-antigens have been linked to immunotherapy outcomes in patients. Our hypothesis is that tumors with reduced mutational burden can be maximized for neo-antigen presentation by activating transcription and translation of these sequences through DNMTi treatment. Our preliminary results showed that the DNMTi guadecitabine (SGI-110), a second-generation hypomethylating agent, treatment decreases methyl-cytosine in genomic DNA both in vitro and in vivo. In addition, SGI-110 treatment enhances MHC-II expression on murine mammary carcinoma MMTV-Neu cells upon IFN-γ stimulation in vitro and increases T-cell infiltration in vivo. Currently, we are performing whole-exome-sequencing and RNA-sequencing to track somatic mutations from DNA to RNA. We will further track somatic mutations from RNA→ MHC-presented peptide sequences using MHC immunoprecipitation followed by mass spectroscopy analysis. In addition, we will explore the role of guadecitabine therapeutic priming on response to αPD-L1 immunotherapy. These studies will provide a pre-clinical data to evaluate the potential for combined epigenetic and immune-therapy in a clinical trial for breast cancer.

Citation Format: Luo N, Estrada VM, Sanders ME, Balko JM. Improving immunotherapy response by epigenetic modulation [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-04-02.

Tea Consumption and Health-Related Quality of Life in Older Adults

BACKGROUND

Although tea consumption has been reported to have various health benefits in humans, its association with health-related quality of life (HRQOL) has not been investigated directly. We aimed to examine the relationship between tea consumption and HRQOL among older Chinese adults.

METHODS

We analyzed community-based cross-sectional data of 5,557 older Chinese individuals aged 60 years or older who participated in the Weitang Geriatric Diseases study. Information on tea consumption and HRQOL assessed by the European Quality of Life-5 dimensions (EQ-5D) were collected by questionnaires. We estimated the relationship of tea consumption and the EQ-5D index score using linear regression models and the association between tea consumption and self-reported EQ-5D health problems using logistic regression models.

RESULTS

The EQ-5D index score was higher for habitual tea drinkers than their counterparts. In multivariate linear analyses controlling for socio-demographic conditions, health conditions, and lifestyle habits, the differences in ED-5D index score between individuals with and without tea drinking habits was 0.012 (95% confidence interval, 0.006-0.017). In multivariate logistic analyses, habitual tea drinking was inversely associated with reporting of problems in EQ-5D dimensions mobility (odds ration [OR], 0.44; 95% CI: 0.23-0.84); pain/discomfort (OR, 0.74; 95% CI: 0.61-0.90); and anxiety/depression (OR, 0.60; 95% CI: 0.38-0.97). These associations were more evident for black or oolong tea than green tea.

CONCLUSION

Habitual tea consumption was associated with better HRQOL in older adults.

ARHGAP10, downregulated in ovarian cancer, suppresses tumorigenicity of ovarian cancer cells

Rho GTPase-activating proteins (RhoGAPs) are implicated in the development and progression of ovarian cancer. ARHGAP10 is a member of RhoGAP proteins and inactivates Cdc42 by converting GTP-bound form to GDP-bound form. Here, we aimed to evaluate ARHGAP10 expression profile and functions in ovarian cancer. The decreased expression of ARHGAP10 was found in 77.3% (58/75) of ovarian cancer tissues, compared with their non-tumorous counterparts. Furthermore, overall survival in ovarian cancer patients with higher expression of ARHGAP10 was longer than those with lower expression. Ectopic expression of ARHGAP10 in two ovarian cancer cell lines with lower expression of ARHGAP10 (A2780 and HO-8910) dramatically suppressed cell proliferation in vitro. In nude mice, its stable overexpression significantly inhibited the tumorigenicity of A2780 cells. We further demonstrated that overexpression of ARHGAP10 significantly inhibited cell adhesion, migration and invasion, resulted in cell arrest in G1 phase of cell cycle and a significant increase of apoptosis. Moreover, ARHGAP10 interacted with Cdc42 and overexpression of ARHGAP10 inhibited the activity of Cdc42 in A2780 cells. Gene set enrichment analysis on The Cancer Genome Atlas dataset showed that KEGG cell cycle, replication and base excision repair (BER) pathways were correlatively with the ARHGAP10 expression, which was further confirmed in ovarian cancer cells by western blotting. Hence, ARHGAP10 may serve as a tumor suppressor through inactivating Cdc42, as well as inhibiting cell cycle, replication and BER pathways. Our data suggest an important role of ARHGAP10 in the molecular etiology of cancer and implicate the potential application of ARHGAP10 in cancer therapy.

Do Chinese have similar health-state preferences? A comparison of mainland Chinese and Singaporean Chinese

BACKGROUND

Little is known about whether health-state preferences differ among Chinese populations. This study compared the preference values for EQ-5D-5L health states between mainland Chinese and Singaporean Chinese.

METHODS

The preference values for ten EQ-5D-5L health states were elicited from general population samples of mainland Chinese and Singaporeans. In computer-assisted self-interviews, each participant completed five time trade-off (TTO) tasks to value five different EQ-5D-5L health states. The difference in TTO values between mainland Chinese and Singaporean Chinese was examined using random-effects linear regression and logistic regression models.

RESULTS

A total of 194 eligible mainland Chinese and 145 eligible Singaporean Chinese provided data for this study. All ten health states considered, the mean TTO value was 0.18 for Singaporean Chinese and 0.35 for mainland Chinese, with the unadjusted and adjusted difference [95% confidence interval (CI)] being -0.17 (-0.28, -0.07) and -0.16 (-0.27, -0.05). Singaporean Chinese had substantially lower TTO values than mainland Chinese for states with severe or extreme problems, with the adjusted difference being -0.30 (95% CI -0.42, -0.17). On the other hand, Singaporean Chinese and mainland Chinese had similar TTO values for states with mild or moderate problems, with the adjusted (95% CI) difference being 0.04 (-0.07, 0.15). Logistic regression analysis showed that Singaporean Chinese were more likely to rate health states with severe or extreme problems as worse than death compared to mainland Chinese.

CONCLUSIONS

Mainland Chinese and Singaporean Chinese have different preferences for EQ-5D-5L health states, supporting the development of local value sets for the EQ-5D-5L instrument for the two populations.

TIFA, an inflammatory signaling adaptor, is tumor suppressive for liver cancer

TIFA (TNF receptor associated factor (TRAF)-interacting protein with a Forkhead-associated (FHA) domain), also called T2BP, was first identified using a yeast two-hybrid screening. TIFA contains a FHA domain, which directly binds phosphothreonine and phosphoserine, and a consensus TRAF6-binding motif. TIFA-mediated oligomerization and poly-ubiquitinylation of TRAF6 mediates signaling downstream of the Tumor necrosis factor alpha receptor 1 (TNFaR-I) and interleukin-1/Toll-like receptor 4 (TLR4) pathways. Examining TIFA expression in hepatocellular carcinoma (HCC) tissues microarrays, we noted marked decreases TIFA reactivity in tumor versus control samples. In agreement, we found that HCC cell lines show reduced TIFA expression levels versus normal liver controls. Reconstituting TIFA expression in HCC cell lines promoted two independent apoptosis signaling pathways: the induction of p53 and cell cycle arrest, and the activation of caspase-8 and caspase-3. In contrast, the expression of a non-oligomerizing mutant of TIFA impacted cells minimally, and suppression of TIFA expression protected cells from apoptosis. Mice bearing TIFA overexpression hepatocellular xenografts develop smaller tumors versus TIFA mutant tumors; terminal deoxynucleotidyl transferase dUTP nick end labeling staining demonstrates increased cell apoptosis, and decreased proliferation, reflecting cell cycle arrest. Interestingly, p53 has a greater role in decreased proliferation than cell death, as it appeared dispensable for TIFA-induced cell killing. The findings demonstrate a novel suppressive role of TIFA in HCC progression via promotion of cell death independent of p53.

Health-related quality of life of Asian patients with end-stage renal disease (ESRD) in Singapore

BACKGROUND

This study aimed to identify factors associated with the health-related quality of life (HRQOL) of multiethnic Asian end-stage renal disease (ESRD) patients treated with dialysis. The role of dialysis modality was also explored.

METHODS

Data used in this study were from two cross-sectional surveys of Singaporean ESRD patients on haemodialysis (HD) or peritoneal dialysis (PD). In both surveys, participants were assessed using the kidney disease quality of life (KDQOL) instrument and questions assessing socio-demographic characteristics. Clinical data including co-morbidity (measured by Charlson comorbidity index [CCI]), albumin level, haemoglobin level, and dialysis-related variables (e.g. dialysis vintage and dialysis adequacy) were retrieved from medical records. The 36-item KDQOL (KDQOL-36) was used to generate three summary scores (physical component summary [PCS], mental component summary [MCS] and kidney disease component summary [KDCS]) and two health utility scores (Short Form 6-dimension [SF-6D] and EuroQol 5-dimension [EQ-5D]). Linear regression analysis was performed to examine the association of factors with each of the HRQOL scale scores.

RESULTS

Five hundred and two patients were included in the study (mean age 57.1 years; male 52.4 %; HD 236, PD 266). Mean [standard deviation (SD)] PCS, MCS and KDCS scores were 37.9 (9.7), 46.4 (10.8) and 57.6 (18.1), respectively. Mean (SD) health utility score was 0.66 (0.12) for SF-6D and 0.60 (0.21) for EQ-5D. In multivariate regression analysis, factors found to be significantly associated with better HRQOL included: young (<45 years) or old age (>60 years), low CCI (<5), high albumin (≥37 g/l) and high haemoglobin (≥11 g/dl) with PCS; long dialysis vintage (≥3.5 years) with MCS; old age, Malay ethnicity and PD modality with KDCS; low CCI, high albumin and high haemoglobin with EQ-5D and high albumin with SF-6D.

CONCLUSIONS

Clinical characteristics are better predictors of HRQOL in ESRD patients than socio-demographics in Singapore. Dialysis modality has no impact on the health utility of those patients.

Association of PELI1 polymorphisms in systemic lupus erythematosus susceptibility in a Chinese population

Objective

Studies in animal models have indicated that Pellino 1 is involved in inflammatory and autoimmune diseases, such as systemic lupus erythematosus (SLE). The current study was designed to determine whether PELI1 confers genetic susceptibility to SLE in humans, as assessed in a Chinese Han population.

Methods

Blood samples were drawn from patients diagnosed with SLE and healthy volunteers. Three single nucleotide polymorphism (SNP) loci with a minor allele frequency of at least 0.05 were chosen to evaluate the correlation between PELI1 genotype and the incidence of SLE.

Results

There was a significant difference in the frequency distribution of the rs329497 allele between the SLE patients and the healthy controls (A vs. G; Bonferroni corrected p = 0.036, odds ratio = 0.75, 95% confidence interval = 0.60–0.94). No differences in the genotype and allele frequencies of other SNP loci were observed between the two groups. Furthermore, the alleles and genotypes of the three SNPs were not associated with lupus nephritis.

Conclusion

In the Chinese Han population, PELI1 SNPs may be associated with SLE susceptibility.

Cross-cultural measurement equivalence of the EQ-5D-5L items for English-speaking Asians in Singapore

PURPOSE

To investigate how the response labels of the 5-level EQ-5D (EQ-5D-5L) items are interpreted and used by English-speaking Chinese and non-Chinese Singaporeans, as a means to assessing whether those items are cross-culturally equivalent health-status measures in this Asian population.

METHODS

In face-to-face interviews, Chinese, Malay and Indian visitors to a primary care institution in Singapore were asked to rate the relative severity conveyed by EQ-5D-5L response labels, each containing the keyword of 'no(t),' 'slight(ly),' 'moderate(ly),' 'severe(ly),' or 'unable'/'extreme(ly),' using a 0-100 numerical rating scale. Participants were also asked to describe 25 hypothetical health states using the EQ-5D-5L response labels. Differences between Chinese and Malay/Indian participants in label interpretation and selection were examined using multivariate regression analysis to adjust for participant characteristics.

RESULTS

The differences in adjusted mean severity scores for individual EQ-5D-5L labels between Chinese (n = 148) and non-Chinese (Malay: n = 53; Indian: n = 56) participants ranged from 0.0 to 9.0. The relative severity of the labels to the participants supported the ordinality of the EQ-5D-5L response labels and was similar across ethnic groups. Chinese and non-Chinese participants selected similar response labels to describe each hypothetical health state, with the adjusted odds ratios of selecting any type of the five response labels for non-Chinese versus Chinese participants ranging from 0.92 to 1.15 (p > 0.05 for all).

CONCLUSIONS

The EQ-5D-5L items are likely to generate equivalent health outcomes between English-speaking Chinese and non-Chinese Singaporeans.

Immunological changes after ASIT in AD allergen-specific immunotherapy and their potential correlation with clinical response in patients with atopic dermatitis patients sensitized to house dust mite

BACKGROUND

Allergen-specific immunotherapy (ASIT) is the main treatment for inducing long-term immunological and clinical tolerance in patients with IgE-mediated allergic diseases. Recent open-label and controlled studies on the efficacy of ASIT in patients with atopic dermatitis (AD) have provided promising results. However, data about possible relationship between the improvement of clinical symptoms and changes of serum cytokines are limited.

METHODS

Seventy-nine patients with moderate to severe AD sensitized to house dust mite (HDM) were enrolled. Fifty-eight patients were treated with ASIT and 11 controls received only symptomatic treatment. The disease activity in AD patients was evaluated by using the patient-oriented eczema measure (POEM) system. Serum interleukin (IL)-4, IL-10, interferon (IFN)-γ, transforming growth factor (TGF) β1, total IgE, HDM-specific IgE (s-IgE) and HDM-specific IgG4 (s-IgG4) were measured before and after 2 years of therapy.

RESULTS

The mean patient-oriented eczema measure system (POEM) score of AD patients with ASIT significantly decreased after 2 years of treatment, compared to that in patients without ASIT. After ASIT, the serum levels of IL-10, TGF-β1, IFN-γ and s-IgG4 increased, while the level of IL-4 decreased. The change in the POEM score was negatively correlated with changes of serum concentration of TGF-β1, s-IgG4 and IFN-γ. Furthermore, s-IgG4 levels were positively correlated with changes in the IL-10 levels. No correlation between POEM score and serum IL-10 or IL-4 was observed.

CONCLUSION

Clinical symptoms and the quality of life of AD with HDM sensitization could be improved after 2 years of ASIT. Changes in serum IL-10, TGF-β1, s-IgG4 and IFN-γ might be considered as biomarkers to assist clinical evaluation of the therapeutic effects of ASIT in patients with AD.

Caspase-9 mediates Puma activation in UCN-01-induced apoptosis

The protein kinase inhibitor 7-hydroxystaurosporine (UCN-01) is one of the most potent and frequently used proapoptotic stimuli. The BH3-only molecule of Bcl-2 family proteins has been reported to contribute to UCN-01-induced apoptosis. Here we have found that UCN-01 triggers Puma-induced mitochondrial apoptosis pathway. Our data confirmed that Akt-FoxO3a pathway mediated Puma activation. Importantly, we elucidate the detailed mechanisms of Puma-induced apoptosis. Our data have also demonstrated that caspase-9 is a decisive molecule of Puma induction after UCN-01 treatment. Caspase-9 mediates apoptosis through two kinds of feedback loops. On the one hand, caspase-9 enhances Puma activation by cleaving Bcl-2 and Bcl-xL independent of caspase-3. On the other hand, caspase-9 directly activated caspase-3 in the presence of caspase-3. Caspase-3 could cleave XIAP in an another positive feedback loop to further sensitize cancer cells to UCN-01-induced apoptosis. Therefore, caspase-9 mediates Puma activation to determine the threshold for overcoming chemoresistance in cancer cells.

Role of the DSC1 channel in regulating neuronal excitability in Drosophila melanogaster: extending nervous system stability under stress

Voltage-gated ion channels are essential for electrical signaling in neurons and other excitable cells. Among them, voltage-gated sodium and calcium channels are four-domain proteins, and ion selectivity is strongly influenced by a ring of amino acids in the pore regions of these channels. Sodium channels contain a DEKA motif (i.e., amino acids D, E, K, and A at the pore positions of domains I, II, III, and IV, respectively), whereas voltage-gated calcium channels contain an EEEE motif (i.e., acidic residues, E, at all four positions). Recently, a novel family of ion channel proteins that contain an intermediate DEEA motif has been found in a variety of invertebrate species. However, the physiological role of this new family of ion channels in animal biology remains elusive. DSC1 in Drosophila melanogaster is a prototype of this new family of ion channels. In this study, we generated two DSC1 knockout lines using ends-out gene targeting via homologous recombination. DSC1 mutant flies exhibited impaired olfaction and a distinct jumpy phenotype that is intensified by heat shock and starvation. Electrophysiological analysis of the giant fiber system (GFS), a well-defined central neural circuit, revealed that DSC1 mutants are altered in the activities of the GFS, including the ability of the GFS to follow repetitive stimulation (i.e., following ability) and response to heat shock, starvation, and pyrethroid insecticides. These results reveal an important role of the DSC1 channel in modulating the stability of neural circuits, particularly under environmental stresses, likely by maintaining the sustainability of synaptic transmission.

Voltage-gated sodium and calcium channels are four-domain proteins that are essential for electrical signaling in neurons and other excitable cells. Recent genomic and functional analyses reveal a novel family of four-domain, Ca²⁺-selective cation channels in a variety of invertebrates, from sea anemones to insects. The amino acid sequences and gating properties of these channels appear to be intermediate between sodium and calcium channels; as such, these channels could potentially be an important evolutionary link between sodium and calcium channels. Despite the intriguing nature of this family of cation channels, their role in animal physiology remains mysterious. In this study, taking advantage of the genetic tractability of the fruit fly, Drosophila melanogaster, we examined the physiological role of such a channel, called DSC1, in this model insect. We generated two DSC1 knockout lines and conducted behavioral and electrophysiological analyses. Our results show that the DSC1 channel contributes to neuronal excitability regulation and plays a unique role in retaining stability of the nervous system function in response to environmental stresses, including heat shock and starvation. Interestingly, the DSC1 knockout flies were also more susceptible to pyrethroid insecticides, which are used globally as a major weapon against the malaria-carrying mosquitoes.

Prostaglandin A2 enhances cellular insulin sensitivity via a mechanism that involves the orphan nuclear receptor NR4A3

We have previously reported that members of the NR4A family of orphan nuclear receptors can augment insulin's ability to stimulate glucose transport in adipocytes. In the current study, we endeavored to test for an insulin-sensitizing effect in muscle cells and to identify a potential transactivator. Lentiviral constructs were used to engineer both hyperexpression and shRNA silencing of NR4A3 in C2C12 myocytes. The NR4A3 hyper-expression construct led to a significant increase in glucose transport rates in the presence of maximal insulin while the NR4A3 knock-down exhibited a significant reduction in insulin-stimulated glucose transport rates. Consistently, insulin-mediated AKT phosphorylation was increased by NR4A3 hyperexpression and decreased following shRNA NR4A3 suppression. Then, we examined effects of prostaglandin A2 (PGA2) on insulin action and NR4A3 transactivation. PGA2 augmented insulin-stimulated glucose uptake in C2C12 myocytes and AKT phosphorylation after 12-h treatment, without significant effects on basal transport or basal AKT phosphorylation. More importantly, we demonstrated that PGA2 led to a greater improvement in insulin-stimulated glucose rates in NR4A3 overexpressing C2C12 myocytes, when compared with Lac-Z controls stimulated with insulin and PGA2. Moreover, the sensitizing effect of PGA2 was significantly diminished in NR4A3 knockdown myocytes compared to scramble controls. These results show for the first time that: (i) PGA2 augments insulin action in myocytes as manifested by enhanced stimulation of glucose transport and AKT phosphorylation; and (ii) the insulin sensitizing effect is dependent upon the orphan nuclear receptor NR4A3.

Effects of transcranial direct current stimulation on hemichannel pannexin-1 and neural plasticity in rat model of cerebral infarction

The aim of this study was to investigate the effects of transcranial direct current stimulation (TDCS) on hemichannel pannexin-1 (PX1) in cortical neurons and neural plasticity, and explore the optimal time window of TDCS therapy after stroke. Adult male Sprague-Dawley rats (n=90) were randomly assigned to sham operation, middle cerebral artery occlusion (MCAO), and TDCS groups, and underwent sham operation, unilateral middle cerebral artery (MCA) electrocoagulation, and unilateral MCA electrocoagulation plus TDCS (daily anodal and cathodal 10 Hz, 0.1 mA TDCS for 30 min beginning day 1 after stroke), respectively. Motor function was assessed using the beam walking test (BWT), and density of dendritic spines (DS) and PX1 mRNA expression were compared among groups on days 3, 7, and 14 after stroke. Effects of PX1 blockage on DS in hippocampal neurons after hypoxia-ischemia were observed. TDCS significantly improved motor function on days 7 and 14 after stroke as indicated by reduced BWT scores compared with the MCAO group. The density of DS was decreased after stroke; the TDCS group had increased DS density compared with the MCAO group on days 3, 7, and 14 (all P<0.0001). Cerebral infarction induced increased PX1 mRNA expression on days 3, 7, and 14 (P<0.0001), and the peak PX1 mRNA expression was observed on day 7. TDCS did not decrease the up-regulated PX1 mRNA expression after stroke on day 3, but did reduce the increased post-stroke PX1 mRNA expression on days 7 and 14 (P<0.0001). TDCS increased the DS density after stroke, indicating that it may promote neural plasticity after stroke. TDCS intervention from day 7 to day 14 after stroke demonstrated motor function improvement and can down-regulate the elevated PX1 mRNA expression after stroke.

Estimating the lifetime economic burden of Parkinson's disease in Singapore

BACKGROUND AND PURPOSE

We aimed to estimate the lifetime cost of Parkinson's disease (PD) from the societal perspective.

METHODS

A convenience sample of English or Chinese-speaking patients with PD was recruited from a PD and Movement Disorders Centre in Singapore to complete a financial burden questionnaire. Sociodemographic and clinical data were retrieved from hospital databases. Markov cohort model analysis was performed (cycle length, 1-year; duration, death or reached 100 years old). Patients were assumed to progress from one Markov state to the next state or death without skipping states or regressing. All model parameters were based on published local data.

RESULTS

In 195 patients with PD (median age: 68.9, male: 51.8%), the simulated lifetime cost of PD was Singapore Dollar (SGD) 60,487 (EUR purchasing power parity 56,253) per patient. Direct medical, non-medical and indirect cost accounted for 18.8%, 12.8% and 68.4% of total lifetime cost, respectively. The top three components of total lifetime cost were productivity losses (67.6%), pharmacotherapy (11.4%) and home care (8.7%). One-way sensitivity analysis and probabilistic sensitivity analyses revealed that estimates were sensitive to cost at H&Y stage 1, 2 and 2.5 and productivity losses.

CONCLUSIONS

The lifetime cost of PD is evaluated for the first time. This cost is substantial and comparable to the lifetime cost of intracerebral haemorrhage in at least one study. Our study identified several priority areas for research and policy formulation: reducing productivity losses, reducing cost of pharmacotherapy, avoiding hospitalization and reducing home care cost.

Validity of EuroQOL-5D, time trade-off, and standard gamble for age-related macular degeneration in the Singapore population

BACKGROUND/AIMS

Utility values of age-related macular degeneration (AMD) in Asian patients are unknown. This study aims to assess utility values and construct validity of the EuroQOL-5D (EQ-5D), time trade-off (TTO), and standard gamble (SG) instruments in the Singapore multi-ethnic AMD population.

METHODS

Cross-sectional, two-centre, institution-based study. Visual acuity (VA), clinical AMD severity, and utility scores on the EQ-5D, TTO, and SG were obtained from 338 AMD patients. VA was analysed in terms of the better-seeing eye (BEVA), worse-seeing eye (WEVA), and weighted average of both eyes (WVA). We evaluated SG on the perfect health-death (SG(death)) and binocular perfect vision-binocular blindness (SG(blindness)) scales. Construct validity was determined by testing a priorihypotheses relating the EQ-5D, TTO, and SG utility scores to VA and clinical AMD severity.

RESULTS

The mean utilities on the EQ-5D, TTO, SG(death), and SG(blindness) were 0.89, 0.81, 0.86, and 0.90, respectively. EQ-5D scores correlated weakly with BEVA, WEVA, and WVA (Pearson's correlation coefficients -0.291, -0.247, and -0.305 respectively, P<0.001 for all). SG(death) and SG(blindness) demonstrated no correlation with BEVA, WEVA, or WVA (Pearson's correlation coefficients, range -0.06 to -0.125). TTO showed weak association only with WEVA and WVA (correlation coefficients -0.237, -0.228, P<0.0001), but not with BEVA (correlation coefficient -0.161). Clinical AMD severity correlated with EQ-5D and SG(death), but not with TTO and SG(blindness) (P=0.004, 0.002, 0.235, and 0.069, respectively).

CONCLUSIONS

AMD has a negative impact on utilities, although utility scores were high compared with Western cohorts. EQ-5D, TTO, and SG showed suboptimal construct validity, suggesting that health status utilities may not be sufficiently robust for cost-utility analyses in this population.

Substitutions in the domain III voltage-sensing module enhance the sensitivity of an insect sodium channel to a scorpion beta-toxin

Scorpion β-toxins bind to the extracellular regions of the voltage-sensing module of domain II and to the pore module of domain III in voltage-gated sodium channels and enhance channel activation by trapping and stabilizing the voltage sensor of domain II in its activated state. We investigated the interaction of a highly potent insect-selective scorpion depressant β-toxin, Lqh-dprIT(3), from Leiurus quinquestriatus hebraeus with insect sodium channels from Blattella germanica (BgNa(v)). Like other scorpion β-toxins, Lqh-dprIT(3) shifts the voltage dependence of activation of BgNa(v) channels expressed in Xenopus oocytes to more negative membrane potentials but only after strong depolarizing prepulses. Notably, among 10 BgNa(v) splice variants tested for their sensitivity to the toxin, only BgNa(v)1-1 was hypersensitive due to an L1285P substitution in IIIS1 resulting from a U-to-C RNA-editing event. Furthermore, charge reversal of a negatively charged residue (E1290K) at the extracellular end of IIIS1 and the two innermost positively charged residues (R4E and R5E) in IIIS4 also increased the channel sensitivity to Lqh-dprIT(3). Besides enhancement of toxin sensitivity, the R4E substitution caused an additional 20-mV negative shift in the voltage dependence of activation of toxin-modified channels, inducing a unique toxin-modified state. Our findings provide the first direct evidence for the involvement of the domain III voltage-sensing module in the action of scorpion β-toxins. This hypersensitivity most likely reflects an increase in IIS4 trapping via allosteric mechanisms, suggesting coupling between the voltage sensors in neighboring domains during channel activation.

Economic burden of Parkinson's disease in Singapore

BACKGROUND

This study was carried out to evaluate the economic burden of Parkinson's disease (PD) and factors independently associated with individual components of total cost in Singapore.

METHODS

A consecutive sample of 195 patients with PD (mean age: 68.2, men: 51.8%) attending a tertiary neuroscience clinic were identified and interviewed using standardized questionnaires including a financial burden questionnaire, two Health Related Quality of Life (HRQoL) questionnaires and the Beck Depression Inventory questionnaire.

RESULTS

Annual total cost of PD from a societal perspective was SGD11345 (USD10129) per patient, with direct cost accounted for 38.5% and indirect cost 61.5%. The main cost components for direct medical cost, direct non-medical cost, and indirect cost was pharmacotherapy (50.4%), home care (76.1%), and productivity loss (97.9%), respectively. In multiple linear regression analysis, higher education, younger age and longer duration of PD were associated with higher total cost.

CONCLUSIONS

Parkinson's disease exerts a considerable burden on patients, health care system and society in Singapore. As productivity loss accounts for a large share of the economic burden imposed by PD, treatments and health care programmes with potential for returning patients to higher productivity are urgently needed.

A negative charge in transmembrane segment 1 of domain II of the cockroach sodium channel is critical for channel gating and action of pyrethroid insecticides

Voltage-gated sodium channels are the primary target of pyrethroids, an important class of synthetic insecticides. Pyrethroids bind to a distinct receptor site on sodium channels and prolong the open state by inhibiting channel deactivation and inactivation. Recent studies have begun to reveal sodium channel residues important for pyrethroid binding. However, how pyrethroid binding leads to inhibition of sodium channel deactivation and inactivation remains elusive. In this study, we show that a negatively charged aspartic acid residue at position 802 (D802) located in the extracellular end of transmembrane segment 1 of domain II (IIS1) is critical for both the action of pyrethroids and the voltage dependence of channel activation. Charge-reversing or -neutralizing substitutions (K, G, or A) of D802 shifted the voltage dependence of activation in the depolarizing direction and reduced channel sensitivity to deltamethrin, a pyrethroid insecticide. The charge-reversing mutation D802K also accelerated open-state deactivation, which may have counteracted the inhibition of sodium channel deactivation by deltamethrin. In contrast, the D802G substitution slowed open-state deactivation, suggesting an additional mechanism for neutralizing the action of deltamethrin. Importantly, Schild analysis showed that D802 is not involved in pyrethroid binding. Thus, we have identified a sodium channel residue that is critical for regulating the action of pyrethroids on the sodium channel without affecting the receptor site of pyrethroids.

A role for S6 kinase and serotonin in postmating dietary switch and balance of nutrients in D. melanogaster

Balancing intake of diverse nutrients is important for organismal growth, reproduction, and survival. A shift in an organism's optimal diet due to changes in nutritional requirements after developmental or environmental changes is referred to as dietary switch and has been observed in several species. Here we demonstrate that female Drosophila melanogaster also undergo a dietary switch following mating that leads to an increased preference for yeast, the major source of protein in their diet. We also demonstrate that S6 kinase (S6K) and serotonin production are involved in the postmating dietary switch. To further investigate the ability of D. melanogaster to balance nutrient intake, we examined the dietary preferences of adult flies following deprivation of yeast or sucrose. We observe that following conditioning on a diet deficient in either carbohydrates or yeast, D. melanogaster show a strong preference for the deficient nutrient. Furthermore, flies with activated dS6K or flies fed a serotonin precursor exhibit enhanced preference for yeast in this assay. Our results suggest that TOR signaling and serotonin may play an important role in maintaining nutrient balance in D. melanogaster. These studies may contribute to our understanding of metabolic disorders such as obesity and diabetes.

Molecular determinants on the insect sodium channel for the specific action of type II pyrethroid insecticides

Pyrethroid insecticides are classified as type I or type II based on their distinct symptomology and effects on sodium channel gating. Structurally, type II pyrethroids possess an alpha-cyano group at the phenylbenzyl alcohol position, which is lacking in type I pyrethroids. Both type I and type II pyrethroids inhibit deactivation consequently prolonging the opening of sodium channels. However, type II pyrethroids inhibit the deactivation of sodium channels to a greater extent than type I pyrethroids inducing much slower decaying of tail currents upon repolarization. The molecular basis of a type II-specific action, however, is not known. Here we report the identification of a residue G(1111) and two positively charged lysines immediately downstream of G(1111) in the intracellular linker connecting domains II and III of the cockroach sodium channel that are specifically involved in the action of type II pyrethroids, but not in the action of type I pyrethroids. Deletion of G(1111), a consequence of alternative splicing, reduced the sodium channel sensitivity to type II pyrethroids, but had no effect on channel sensitivity to type I pyrethroids. Interestingly, charge neutralization or charge reversal of two positively charged lysines (Ks) downstream of G(1111) had a similar effect. These results provide the molecular insight into the type II-specific interaction of pyrethroids with the sodium channel at the molecular level.