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21
result(s) for
"Shing, Vivian"
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Boosting NAD+ blunts TLR4-induced type I IFN in control and systemic lupus erythematosus monocytes
by
Wu, Kaiyuan
,
Singh, Komudi
,
Meadows, Allison M.
in
Alzheimer's disease
,
Autophagy
,
Biomedical research
2022
BACKGROUNDFasting and NAD+-boosting compounds, including NAD+ precursor nicotinamide riboside (NR), confer antiinflammatory effects. However, the underlying mechanisms and therapeutic potential are incompletely defined.METHODSWe explored the underlying biology in myeloid cells from healthy volunteers following in vivo placebo or NR administration and subsequently tested the findings in vitro in monocytes extracted from patients with systemic lupus erythematosus (SLE).RESULTSRNA-Seq of unstimulated and LPS-activated monocytes implicated NR in the regulation of autophagy and type I IFN signaling. In primary monocytes, NR blunted LPS-induced IFN-β production, and genetic or pharmacological disruption of autophagy phenocopied this effect. Given that NAD+ is a coenzyme in oxidoreductive reactions, metabolomics was performed and identified that NR increased the inosine level. Inosine supplementation similarly blunted autophagy and IFN-β release. Finally, because SLE exhibits type I IFN dysregulation, we assessed the NR effect on monocytes from patients with SLE and found that NR reduced autophagy and IFN-β release.CONCLUSIONWe conclude that NR, in an NAD+-dependent manner and in part via inosine signaling, mediated suppression of autophagy and attenuated type I IFN in myeloid cells, and we identified NR as a potential adjunct for SLE management.TRIAL REGISTRATIONClinicalTrials.gov registration numbers NCT02812238, NCT00001846, and NCT00001372.FUNDINGThis work was supported by the NHLBI and NIAMS Intramural Research divisions.
Journal Article
Boosting NAD.sup.+ blunts TLR4-induced type I IFN in control and systemic lupus erythematosus monocytes
by
Meadows, Allison M
,
Wu, Kaiyuan
,
Singh, Komudi
in
Care and treatment
,
Cellular signal transduction
,
Health aspects
2022
BACKGROUND. Fasting and [NAD.sup.+]-boosting compounds, including [NAD.sup.+] precursor nicotinamide riboside (NR), confer antiinflammatory effects. However, the underlying mechanisms and therapeutic potential are incompletely defined. METHODS. We explored the underlying biology in myeloid cells from healthy volunteers following in vivo placebo or NR administration and subsequently tested the findings in vitro in monocytes extracted from patients with systemic lupus erythematosus (SLE). RESULTS. RNA-Seq of unstimulated and LPS-activated monocytes implicated NR in the regulation of autophagy and type I IFN signaling. In primary monocytes, NR blunted LPS-induced IFN-[beta] production, and genetic or pharmacological disruption of autophagy phenocopied this effect. Given that [NAD.sup.+] is a coenzyme in oxidoreductive reactions, metabolomics was performed and identified that NR increased the inosine level. Inosine supplementation similarly blunted autophagy and IFN-[beta] release. Finally, because SLE exhibits type I IFN dysregulation, we assessed the NR effect on monocytes from patients with SLE and found that NR reduced autophagy and IFN-[beta] release. CONCLUSION. We conclude that NR, in an [NAD.sup.+]-dependent manner and in part via inosine signaling, mediated suppression of autophagy and attenuated type I IFN in myeloid cells, and we identified NR as a potential adjunct for SLE management. TRIAL REGISTRATION. ClinicalTrials.gov registration numbers NCT02812238, NCT00001846, and NCT00001372. FUNDING. This work was supported by the NHLBI and NIAMS Intramural Research divisions.
Journal Article
The mitochondrial thiolase ACAT1 regulates monocyte/macrophage type I interferon via epigenetic control
2024
Lipid-derived acetyl-CoA is shown to be the major carbon source for histone acetylation. However, there is no direct evidence demonstrating lipid metabolic pathway contribututions to this process. Mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1) catalyzes the final step of ß-oxidation, the aerobic process catabolizing fatty acids (FA) into acetyl-CoA. To investigate this in the context of immunometabolism, we generated macrophage cell line lacking ACAT1.
C-carbon tracing combined with mass spectrometry confirmed incorporation of FA-derived carbons into histone H3 and this incorporation was reduced in ACAT1 KO macrophage cells. RNA-seq identified a subset of genes downregulated in ACAT1 KO cells including STAT1/2 and interferon stimulated genes (ISGs). CHIP analysis demonstrated reduced acetyl-H3 binding to STAT1 promoter/enhancer regions. Increasing histone acetylation rescued STAT1/2 expression in ACAT1 KO cells. Concomitantly, ligand triggered IFNβ release was blunted in ACAT1 KO cells and rescued by reconstitution of ACAT1. Furthermore, ACAT1 promotes FA-mediated histone acetylation in an acetylcarnitine shuttle-dependent manner. In patients with obesity, levels of ACAT1 and histone acetylation are abnormally elevated. Thus, our study identified a novel link between ACAT1 mediated FA metabolism and epigenetic modification on STAT1/2 that uncovers a regulatory role of lipid metabolism in innate immune signaling and opens novel avenues for interventions in human diseases such as obesity.
Journal Article
Study of Microalgae Biofixation with Bacteria Carbonic Anhydrase for Carbon Capture and Utilization
by
Wong, Sum-Yi Sammie
,
Lam, Wai-Yu Vivian
,
Kwok, Ho-Pan
in
Algae
,
Alternative energy sources
,
Atmospheric carbon dioxide
2024
Climate change has been significantly affecting human activities due to the accumulation of greenhouse gases, such as carbon dioxide. Biofixation of carbon dioxide (CO2) has been investigated to reduce the atmospheric CO2 level and slow the rapid increase in the global temperature. Carbon capture and utilization (CCU) can be performed by either physio-chemical or biological methods. The latter takes place in ambient temperature and mild conditions, such that there is no need for high pressure and high energy consumption nor hazardous chemicals. Biofixation by microalgae has been utilized to capture CO2 and the microalgae biomass collected after the process can be further utilized in renewable biofuel generation. On the other hand, microbial enzymes, such as carbonic anhydrase (CA), have been investigated to speed up the whole biofixation process by increasing the conversion rate of CO2 into bicarbonate (HCO3−) in a culture medium and the latter can be readily used by microalgae to increase CO2 removal. In this study, in the presence of 20% CO2 (v/v) gas in air and 5 mL CA enzyme extract (0.5 mg mL−1 protein), we can significantly increase the biofixation rate using marine green microalgae, Tetraselmis sp. Results showed that the biofixation rate can be increased from 0.64 g L−1 day−1 (no CA and at 0.04% CO2) to 4.26 g L−1 day−1. The effects of different experimental conditions such as pH, nutrient levels and working CO2 concentration levels on Tetraselmis sp. growth and CO2 biofixation (CO2 removal) rate have been investigated. This study demonstrates a new alternative approach for effective carbon capture and utilization (CCU) using microalgae which can be applied to achieve the goal of carbon neutrality.
Journal Article
A clinico-genomic prognostic model for primary myelodysplastic neoplasm in Asia
by
Chin, Lynn
,
Wu, Tony K. Y.
,
Kwong, Yok-Lam
in
692/308/2056
,
692/699/1541/1990/1673
,
Adolescent
2025
A personalized prognostic model that takes into account the unique molecular features of primary myelodysplastic neoplasm (MDS) in Asia patients is lacking. Diagnostic clinicopathologic features, cytogenetic changes, and gene mutations of ethnic Asian patients with primary MDS were analyzed. Variables were evaluated for associations with overall survival (OS), leukemia-free survival (LFS), and time to progression to secondary AML (TTP-sAML). Prognostic scores were built as a weighted sum of prognostic variables for each patient. The cohort comprised 1225 patients, with at least one gene mutation identified in 1177 patients (96%). Genomic factors associated with inferior outcomes included monosomy 7, del(5q), and
GNAS
and
TP53
mutations for OS; trisomy 19, del(5q), monosomy 7, and
GNAS
,
PTPN11
and
TP53
mutations for LFS; and i(17q), del(5q), and
NPM1
,
NRAS
,
GNAS
,
IDH2
,
SF3B1
and
RUNX1
mutations for TTP-sAML. The Asian Prognostic Scoring System (APSS) was determined, stratifying patients into six prognostic risk categories. The APSS, compared with the International Prognostic Scoring System molecular (IPSS-M), showed superior concordance indices (C-indices) for OS (0.73
versus
0.57), LFS (0.72
versus
0.59), and TTP-sAML (0.75
versus
0.65) for this Asian cohort. In conclusion, the APSS enhanced prognostication of primary MDS in Asia.
Journal Article
Adiponectin is Protective against Oxidative Stress Induced Cytotoxicity in Amyloid-Beta Neurotoxicity
by
Ho, Jessica Wing-Man
,
Cheng, Kenneth King-Yip
,
Ho, Philip Wing-Lok
in
Activation
,
Adapters
,
Adaptor Proteins, Signal Transducing - metabolism
2012
Beta-amyloid (Aβ ) neurotoxicity is important in Alzheimer's disease (AD) pathogenesis. Aβ neurotoxicity causes oxidative stress, inflammation and mitochondrial damage resulting in neuronal degeneration and death. Oxidative stress, inflammation and mitochondrial failure are also pathophysiological mechanisms of type 2 diabetes (T(2)DM) which is characterized by insulin resistance. Interestingly, T(2)DM increases risk to develop AD which is associated with reduced neuronal insulin sensitivity (central insulin resistance). We studied the potential protective effect of adiponectin (an adipokine with insulin-sensitizing, anti-inflammatory and anti-oxidant properties) against Aβ neurotoxicity in human neuroblastoma cells (SH-SY5Y) transfected with the Swedish amyloid precursor protein (Sw-APP) mutant, which overproduced Aβ with abnormal intracellular Aβ accumulation. Cytotoxicity was measured by assay for lactate dehydrogenase (LDH) released upon cell death and lysis. Our results revealed that Sw-APP transfected SH-SY5Y cells expressed both adiponectin receptor 1 and 2, and had increased AMP-activated protein kinase (AMPK) activation and enhanced nuclear factor-kappa B (NF-κB) activation compared to control empty-vector transfected SH-SY5Y cells. Importantly, adiponectin at physiological concentration of 10 µg/ml protected Sw-APP transfected SH-SY5Y cells against cytotoxicity under oxidative stress induced by hydrogen peroxide. This neuroprotective action of adiponectin against Aβ neurotoxicity-induced cytotoxicity under oxidative stress involved 1) AMPK activation mediated via the endosomal adaptor protein APPL1 (adaptor protein with phosphotyrosine binding, pleckstrin homology domains and leucine zipper motif) and possibly 2) suppression of NF-κB activation. This raises the possibility of novel therapies for AD such as adiponectin receptor agonists.
Journal Article
The effects of a real‐time temperature monitoring non‐ablative monopolar radiofrequency technology on vulvovaginal atrophy symptoms in postmenopausal Chinese women
2024
Background Vulvovaginal atrophy (VVA) includes a wide range of conditions affecting the reproductive and urinary systems, often requiring careful evaluation and management for optimal health. Aims This study aims to evaluate the symptom management effects of a real time temperature‐monitored non‐ablative RF device for the treatment of postmenopausal Chinese women with VVA symptoms. Methods This pilot study involved 24 postmenopausal Chinese women with one or more VVA symptoms, who wished to remain sexually active. VHIS, VAS, and FSFI were used to track and evaluate various aspects of the patient's condition. Analyses were conducted at the end of the study to verify the statistical significance of the treatment's results. Results All patients reported substantial, statistically significant, improvements on every VVA symptom tracked. Approximately 80% of the patients reported total symptom reversal at 12‐week post‐treatment follow‐up. Conclusion This pilot study demonstrated that non‐ablative, monopolar RF technology equipped with real time temperature monitoring is feasible and safe in the treatment of postmenopausal women with VVA symptoms, and efficacious at up to 12 weeks post‐treatment.
Journal Article
Frequent mutation of receptor protein tyrosine phosphatases provides a mechanism for STAT3 hyperactivation in head and neck cancer
2014
The underpinnings of STAT3 hyperphosphorylation resulting in enhanced signaling and cancer progression are incompletely understood. Loss-of-function mutations of enzymes that dephosphorylate STAT3, such as receptor protein tyrosine phosphatases, which are encoded by the PTPR gene family, represent a plausible mechanism of STAT3 hyperactivation. We analyzed whole exome sequencing (n = 374) and reverse-phase protein array data (n = 212) from head and neck squamous cell carcinomas (HNSCCs). PTPR mutations are most common and are associated with significantly increased phospho-STAT3 expression in HNSCC tumors. Expression of receptor-like protein tyrosine phosphatase T (PTPRT) mutant proteins induces STAT3 phosphorylation and cell survival, consistent with a “driver” phenotype. Computational modeling reveals functional consequences of PTPRT mutations on phospho-tyrosine–substrate interactions. A high mutation rate (30%) of PTPR s was found in HNSCC and 14 other solid tumors, suggesting that PTPR alterations, in particular PTPRT mutations, may define a subset of patients where STAT3 pathway inhibitors hold particular promise as effective therapeutic agents.
Journal Article
Methylated Septin 9 and Carcinoembryonic Antigen for Serological Diagnosis and Monitoring of Patients with Colorectal Cancer After Surgery
by
Law, Wai Lun
,
Chan, Cherry Sze Yan
,
Ng, Enders Kai On
in
38/22
,
692/4020
,
692/4020/1503/1504/1885
2019
With the increasing incidence and mortality of colorectal cancer (CRC), early and accurate diagnosis is of paramount priority to combat this cancer. Epigenetic alterations such as DNA methylation are innovative biomarkers for CRC, due to their stability, frequency, and accessibility in bodily fluids. In this study, blood samples were prospectively collected from patients before and after operation for CRC for determination of methylated septin 9 (mSEPT9) and compared to carcinoembryonic antigen (CEA). The sensitivity of using mSEPT9 methylation status for diagnosing CRC was significantly higher than using elevated CEA levels (73.2% vs 48.2%; p value < 0.001). The sensitivities of both tests increased with higher tumor staging (P = 0.004 and 0.04 respectively). Combined mSEPT9 and CEA had higher accuracy than single CEA or mSEPT9 (P = 0.009 and 0.532 separately). An increase in the methylation level of mSEPT9 detected in the post-operative samples was associated with a higher mortality rate (15.2% vs 1.8%; P = 0.024) and the presence of metastasis (27.3% vs 7.0%; P = 0.013). mSEPT9 was more sensitive than CEA for diagnosing CRC, and combined mSEPT9 and CEA was more accurate. After curative resection, detection of increased mSEPT9 methylation level may indicate adverse outcomes.
Journal Article
Tetrandrine inhibits hepatocellular carcinoma cell growth through the caspase pathway and G2/M phase
by
YU, VIVIAN W.L
,
HO, WING SHING
in
Antineoplastic Agents, Phytogenic - pharmacology
,
Apoptosis
,
Benzylisoquinolines - pharmacology
2013
Activation of p53-independent pathways plays an important role in phytochemical-induced apoptosis and is considered to be a crucial factor in the invasion and metastasis of cancer. Previous studies have shown that combined effects of Stephania tetrandra with medicinal herbs exhibit beneficial effects in cancer patients. Tetrandrine, an active component of Stephania tetrandra has been reported to have anticancer properties in cancer cells. However, the mechanism(s) of action of tetrandrine in liver cancer have yet to be fully elucidated. In this study, we investigated the effects of tetrandrine in hepatocellular carcinoma (HCC) cells. The results showed that tetrandrine inhibited HCC cell proliferation by suppression of cell cycle progression at the G2/M phase. Changes in the expression levels of Bax, Bcl, p53, survivin, PCNA, PARP and p21 were observed. In addition, tetrandrine increased caspase-3 expression and induced DNA fragmentation in Huh-7 cells. The results suggest that the anti-cancer effect of tetrandrine in Huh-7 cells may be mediated by p53-independent pathways.
Journal Article