16 results on '"Lok-Yi Chan"'
Search Results
2. High-Throughput Mass Spectrometric Analysis of the Whole Proteome and Secretome From Sinorhizobium fredii Strains CCBAU25509 and CCBAU45436
- Author
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Hafiz Mamoon Rehman, Wai-Lun Cheung, Kwong-Sen Wong, Min Xie, Ching-Yee Luk, Fuk-Ling Wong, Man-Wah Li, Sau-Na Tsai, Wing-Ting To, Lok-Yi Chan, and Hon-Ming Lam
- Subjects
Sinorhizobium fredii ,proteome ,secretome ,nodulation outer proteins ,soybean ,Microbiology ,QR1-502 - Abstract
Sinorhizobium fredii is a dominant rhizobium on alkaline-saline land that can induce nitrogen-fixing symbiotic root nodules in soybean. Two S. fredii strains, CCBAU25509 and CCBAU45436, were used in this study to facilitate in-depth analyses of this species and its interactions with soybean. We have previously completed the full assembly of the genomes and detailed transcriptomic analyses for these two S. fredii strains, CCBAU25509 and CCBAU45436, that exhibit differential compatibility toward some soybean hosts. In this work, we performed high-throughput Orbitrap analyses of the whole proteomes and secretomes of CCBAU25509 and CCBAU45436 at different growth stages. Our proteomic data cover coding sequences in the chromosome, chromid, symbiotic plasmid, and other accessory plasmids. In general, we found higher levels of protein expression by genes in the chromosomal genome, whereas proteins encoded by the symbiotic plasmid were differentially accumulated in bacteroids. We identified secreted proteins from the extracellular medium, including seven and eight Nodulation Outer Proteins (Nops) encoded by the symbiotic plasmid of CCBAU25509 and CCBAU45436, respectively. Differential host restriction of CCBAU25509 and CCBAU45436 is regulated by the allelic type of the soybean Rj2(Rfg1) protein. Using sequencing data from this work and available in public databases, our analysis confirmed that the soybean Rj2(Rfg1) protein has three major allelic types (Rj2/rfg1, rj2/Rfg1, rj2/rfg1) that determine the host restriction of some Bradyrhizobium diazoefficiens and S. fredii strains. A mutant defective in the type 3 protein secretion system (T3SS) in CCBAU25509 allowed this strain to nodulate otherwise-incompatible soybeans carrying the rj2/Rfg1 allelic type, probably by disrupting Nops secretion. The allelic forms of NopP and NopI in S. fredii might be associated with the restriction imposed by Rfg1. By swapping the NopP between CCBAU25509 and CCBAU45436, we found that only the strains carrying NopP from CCBAU45436 could nodulate soybeans carrying the rj2/Rfg1 allelic type. However, no direct interaction between either forms of NopP and Rfg1 could be observed.
- Published
- 2019
- Full Text
- View/download PDF
3. Effects of statins on the inducible degrader of low-density lipoprotein receptor in familial hypercholesterolemia
- Author
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Melody Lok-Yi Chan, Sammy Wing-Ming Shiu, Ching-Lung Cheung, Anskar Yu-Hung Leung, and Kathryn Choon-Beng Tan
- Subjects
ubiquitin-protein ligases ,lipid metabolism ,statin therapy ,familial hypercholesterolemia ,low-density lipoprotein ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
The inducible degrader of low-density lipoprotein receptor (IDOL) is an E3 ubiquitin ligase involved in the post-transcriptional regulation of LDL receptor (LDLR). Statins lower plasma LDL by activating transcription of hepatic LDLR expression, and we have determined whether statins modulate IDOL expression and influence LDLR protein abundance. IDOL expression in monocytes and serum IDOL level was determined in statin-treated familial hypercholesterolemia (FH) patients and compared with control subjects. Serum IDOL level was also evaluated in a group of untreated FH patients before and after the initiation of statin. The mechanism underlying the inhibitory effect of statin on IDOL expression was investigated in vitro. In statin-treated FH patients, serum IDOL level and its expression in monocytes was reduced compared with control (P < 0.05). In contrast, untreated FH patients had higher serum levels of IDOL and proprotein convertase subtilisin/kexintype 9 (PCSK9) than control (P < 0.05), and serum IDOL level decreased after statin therapy (P < 0.05) whereas an increase was observed in PCSK9 level (P < 0.01). In vitro, atorvastatin significantly decreased IDOL abundance in a dose-dependent manner in cultured macrophages and hepatocytes with a concomitant increase in LDLR expression. The transcription of IDOL was restored by adding either an LXR agonist T0901317 or oxysterol 22(R)-hydroxycholesterol, indicating that statin inhibited IDOL expression by reducing LXR activation. The LXR-IDOL-LDLR axis can be modulated by statins in vitro and in vivo. Statins inhibit IDOL expression by reducing LXR activation and upregulate LDLR, and statins exert the opposite effect on IDOL and PCSK9.
- Published
- 2022
- Full Text
- View/download PDF
4. Vascular-targeted TNFα improves tumor blood vessel function and enhances antitumor immunity and chemotherapy in colorectal cancer
- Author
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Lu, Lan, Jie Li, Zhi, Fei Li, Long, Ka Kei Wu, William, Shen, Jing, Zhang, Lin, Lok Yi Chan, Ruby, Yu, Le, Wei Liu, Ya, Xiang Ren, Shun, Ming Chan, Kam, and Hin Cho, Chi
- Published
- 2015
- Full Text
- View/download PDF
5. Genetic and metabolic determinants of low-density lipoprotein in familial hypercholesterolemia
- Author
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Lok-yi Chan
- Published
- 2020
- Full Text
- View/download PDF
6. Increased Detection of Emergent Recombinant Norovirus GII.P16-GII.2 Strains in Young Adults, Hong Kong, China, 2016–2017
- Author
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Nelson Lee, Sonja Jacobsen, Kirsty Kwok, Paul K.S. Chan, Raymond Lai, Lok-Yi Chan, Martin C.W. Chan, Ting Fan Leung, Tin-Nok Hung, E. Anthony S. Nelson, and Sandra Niendorf
- Subjects
Male ,0301 basic medicine ,Epidemiology ,viruses ,lcsh:Medicine ,medicine.disease_cause ,Communicable Diseases, Emerging ,Disease Outbreaks ,recombinant norovirus ,fluids and secretions ,Increased Detection of Emergent Recombinant Norovirus GII.P16-GII.2 Strains in Young Adults, Hong Kong, China ,Genotype ,Pandemic ,older children ,GII ,Young adult ,Child ,Phylogeny ,Caliciviridae Infections ,education.field_of_study ,Dispatch ,virus diseases ,Middle Aged ,Gastroenteritis ,viral load ,Infectious Diseases ,Child, Preschool ,Hong Kong ,Female ,Seasons ,Viral load ,Reassortant Viruses ,Adult ,young adults ,Microbiology (medical) ,China ,medicine.medical_specialty ,Adolescent ,030106 microbiology ,Population ,Biology ,lcsh:Infectious and parasitic diseases ,Young Adult ,03 medical and health sciences ,Molecular genetics ,medicine ,Humans ,lcsh:RC109-216 ,education ,Aged ,lcsh:R ,Norovirus ,Infant ,Virology ,030104 developmental biology - Abstract
A new recombinant norovirus GII.P16-GII.2 outnumbered pandemic GII.4 as the predominant GII genotype in the winter of 2016–2017 in Hong Kong, China. Half of hospitalized case-patients were older children and adults, including 13 young adults. This emergent norovirus targets a wider age population compared with circulating pandemic GII.4 strains.
- Published
- 2017
- Full Text
- View/download PDF
7. High-Throughput Mass Spectrometric Analysis of the Whole Proteome and Secretome From Sinorhizobium fredii Strains CCBAU25509 and CCBAU45436
- Author
-
Hon-Ming Lam, Man-Wah Li, Kwong-Sen Wong, Sau-Na Tsai, Lok-Yi Chan, Ching-Yee Luk, Min Xie, Wing-Ting To, Fuk-Ling Wong, Wai-Lun Cheung, and Hafiz Mamoon Rehman
- Subjects
Microbiology (medical) ,proteome ,Mutant ,lcsh:QR1-502 ,Biology ,Sinorhizobium fredii ,Microbiology ,Genome ,lcsh:Microbiology ,03 medical and health sciences ,Plasmid ,soybean ,Gene ,Bradyrhizobium diazoefficiens ,Original Research ,030304 developmental biology ,Genetics ,0303 health sciences ,030306 microbiology ,food and beverages ,biology.organism_classification ,secretome ,nodulation outer proteins ,Proteome ,Rhizobium - Abstract
Sinorhizobium fredii is a dominant rhizobium on alkaline-saline land that can induce nitrogen-fixing symbiotic root nodules in soybean. Two S. fredii strains, CCBAU25509 and CCBAU45436, were used in this study to facilitate in-depth analyses of this species and its interactions with soybean. We have previously completed the full assembly of the genomes and detailed transcriptomic analyses for these two S. fredii strains, CCBAU25509 and CCBAU45436, that exhibit differential compatibility toward some soybean hosts. In this work, we performed high-throughput Orbitrap analyses of the whole proteomes and secretomes of CCBAU25509 and CCBAU45436 at different growth stages. Our proteomic data cover coding sequences in the chromosome, chromid, symbiotic plasmid, and other accessory plasmids. In general, we found higher levels of protein expression by genes in the chromosomal genome, whereas proteins encoded by the symbiotic plasmid were differentially accumulated in bacteroids. We identified secreted proteins from the extracellular medium, including seven and eight Nodulation Outer Proteins (Nops) encoded by the symbiotic plasmid of CCBAU25509 and CCBAU45436, respectively. Differential host restriction of CCBAU25509 and CCBAU45436 is regulated by the allelic type of the soybean Rj2(Rfg1) protein. Using sequencing data from this work and available in public databases, our analysis confirmed that the soybean Rj2(Rfg1) protein has three major allelic types (Rj2/rfg1, rj2/Rfg1, rj2/rfg1) that determine the host restriction of some Bradyrhizobium diazoefficiens and S. fredii strains. A mutant defective in the type 3 protein secretion system (T3SS) in CCBAU25509 allowed this strain to nodulate otherwise-incompatible soybeans carrying the rj2/Rfg1 allelic type, probably by disrupting Nops secretion. The allelic forms of NopP and NopI in S. fredii might be associated with the restriction imposed by Rfg1. By swapping the NopP between CCBAU25509 and CCBAU45436, we found that only the strains carrying NopP from CCBAU45436 could nodulate soybeans carrying the rj2/Rfg1 allelic type. However, no direct interaction between either forms of NopP and Rfg1 could be observed.
- Published
- 2019
- Full Text
- View/download PDF
8. Response to Alirocumab in Homozygous Familial Hypercholesterolemia: a Case Report
- Author
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Ying Wong, Sammy W.M. Shiu, Kathryn C.B. Tan, and Melody Lok-Yi Chan
- Subjects
Pediatrics ,medicine.medical_specialty ,business.industry ,Internal Medicine ,medicine ,General Medicine ,Familial hypercholesterolemia ,Cardiology and Cardiovascular Medicine ,medicine.disease ,business ,Alirocumab - Published
- 2018
- Full Text
- View/download PDF
9. Response to Alirocumab in Homozygous Familial Hypercholesterolemia: a Case Report
- Author
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Lok-Yi Chan, Melody, primary, Shiu, Sammy, additional, Wong, Ying, additional, and Tan, Kathryn, additional
- Published
- 2018
- Full Text
- View/download PDF
10. Recurrent Infections of Emergent Norovirus GII.17 in an Elderly
- Author
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Martin C.W. Chan, Rity Y. K. Wong, Kirsty Kwok, Nelson Lee, Lok-Yi Chan, Tin-Nok Hung, and Paul K.S. Chan
- Subjects
0301 basic medicine ,Microbiology (medical) ,Norovirus GII ,03 medical and health sciences ,Recurrent infections ,Infectious Diseases ,business.industry ,030106 microbiology ,Medicine ,business ,Virology - Published
- 2016
11. Genetic variations in familial hypercholesterolemia and cascade screening in East Asians
- Author
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Alan C.H. Lee, Chung-Wah Siu, CY Yeung, Kathryn C.B. Tan, Ho-Kwong Pang, Ching-Lung Cheung, Melody Lok-Yi Chan, and Jenny Y. Y. Leung
- Subjects
Adult ,Male ,LDLR gene ,0301 basic medicine ,cascade screening ,Apolipoprotein B ,Disease ,Cascade screening ,Familial hypercholesterolemia ,030105 genetics & heredity ,medicine.disease_cause ,Polymorphism, Single Nucleotide ,Hyperlipoproteinemia Type II ,03 medical and health sciences ,Asian People ,Gene Frequency ,Genetic variation ,Genetics ,medicine ,Humans ,APOB gene ,Molecular Biology ,Genetics (clinical) ,Aged ,Genetic testing ,Mutation ,familial hypercholesterolemia ,biology ,medicine.diagnostic_test ,business.industry ,Original Articles ,Middle Aged ,medicine.disease ,030104 developmental biology ,Receptors, LDL ,Apolipoprotein B-100 ,LDL receptor ,biology.protein ,Female ,Original Article ,lipids (amino acids, peptides, and proteins) ,genetic spectrum ,business - Abstract
Background Familial hypercholesterolemia (FH) is a monogenic disorder of lipoprotein metabolism leading to an increased risk of premature cardiovascular disease. Genetic testing for FH is not commonly used in Asian countries. We aimed to define the genetic spectrum of FH in Hong Kong and to test the feasibility of cascade genetic screening. Methods Ninety‐six Chinese subjects with a clinical diagnosis of FH were recruited, and family‐based cascade screening incorporating genetic testing results was performed. Results Forty‐two distinct mutations were identified in 67% of the index FH cases. The majority of causative mutations were in the LDLR gene. The three commonest mutations in the LDLR gene were NM_000527.4(LDLR): c.1241 T>G, NM_000527.4(LDLR): c.1474G>A, and NM_000527.4(LDLR): c. 682G>A, and nine novel variants were identified. The NM_000384.2(APOB): c.10579 C>T variant of the APOB gene was found in 5% of the index subjects. The presence of causative mutation significantly increased the odds of successful family recruitment for screening with an OR of 3.7 (95% CI: 1.53–9.11, p = 0.004). Conclusion Approximately two‐third of the subjects in this clinically ascertained sample of patients with FH had a discrete genetic basis. Genetic identification improves the response rate and efficiency of family screening.
- Published
- 2018
- Full Text
- View/download PDF
12. Increased Detection of Emergent Recombinant Norovirus GII.P16-GII.2 Strains in Young Adults, Hong Kong, China, 2016-2017.
- Author
-
Kwok, Kirsty, Lee, Nelson, Tin-Nok Hung, Lok-Yi Chan, Nelson, E. S. Anthony, Leung, Ting F., Lai, Raymond W. M., Chan, Paul K. S., Chan, Martin C. W., Niendorf, Sandra, Jacobsen, Sonja, Hung, Tin-Nok, Chan, Lok-Yi, and Nelson, E Anthony S
- Subjects
NOROVIRUSES ,DISEASES in young adults ,GASTROENTERITIS ,WINTER - Abstract
A new recombinant norovirus GII.P16-GII.2 outnumbered pandemic GII.4 as the predominant GII genotype in the winter of 2016-2017 in Hong Kong, China. Half of hospitalized case-patients were older children and adults, including 13 young adults. This emergent norovirus targets a wider age population compared with circulating pandemic GII.4 strains. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. Recurrent Infections of Emergent Norovirus GII.17 in an Elderly Patient.
- Author
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Chan, Martin C. W., Lee, Nelson, Tin-Nok Hung, Lok-Yi Chan, Kirsty Kwok, Wong, Rity Y. K., and Chan, Paul K. S.
- Subjects
NOROVIRUS diseases ,OLDER patients - Abstract
A letter to the editor is presented regarding the case study of an elderly patient who was hospitalized due to recurrent GII.17 Kawasaki infections and gastroenteritis.
- Published
- 2017
- Full Text
- View/download PDF
14. The Current Role and Therapeutic Targets of Vitamin D in Gastrointestinal Inflammation and Cancer
- Author
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Hui Cai, Gan, Xing Li, Ming, Lu, Lan, Lok Yi Chan, Ruby, Hao Wang, Jian, and Hin Cho, Chi
- Abstract
Vitamin D, beyond its classical roles in the regulation of calcium and phosphorus homeostasis and bone metabolism, has been implicated in multiple pathological processes, including progression from inflammation to cancer development and also involvement in autoimmune diseases as well as cardiovascular disorders. In this review, we shall discuss the different roles of vitamin D and its therapeutic targets in different gastrointestinal diseases, focusing on colorectal cancer (CRC) and inflammatory bowel disease (IBD). To this end, vitamin D deficiency has been identified as a risk factor of CRC. On the other hand the active metabolite of vitamin D, 1, 25- dihydroxyvitamin D3 (1, 25(OH)2D3) has multiple anti-cancerous benefits including inhibition of proliferation, induction of apoptosis, promotion of differentiation and suppression of angiogenesis in tumors. In IBD, vitamin D is involved in the pathogenic process through the normalization of immune responses in the colon. With these experimental findings, well-designed and large-scale clinical trials are warranted to further define the therapeutic action of vitamin D in the prevention and/or treatment of IBD and further on CRC in humans.
- Published
- 2015
15. Astragalus saponins downregulate vascular endothelial growth factor under cobalt chloride-stimulated hypoxia in colon cancer cells.
- Author
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Pui-Ching Law, Auyeung, Kathy K., Lok-Yi Chan, and Ko, Joshua K.
- Subjects
ANALYSIS of variance ,ANIMAL experimentation ,HYPOXEMIA ,BIOPHYSICS ,CELL culture ,CELLULAR signal transduction ,CHLORIDES ,GLYCOSIDES ,IMMUNOHISTOCHEMISTRY ,RESEARCH methodology ,MEDICINAL plants ,MICE ,OXIDOREDUCTASES ,POLYMERASE chain reaction ,RESEARCH funding ,STATISTICS ,RAPAMYCIN ,DATA analysis ,VASCULAR endothelial growth factors ,REVERSE transcriptase polymerase chain reaction ,DATA analysis software ,DESCRIPTIVE statistics - Abstract
Background: Our ongoing research has revealed that total saponins extracted from the medicinal herb Radix Astragali (AST) exhibits significant growth-inhibitory and proapoptotic effects in human cancer cells. In the present study, the potential of AST in controlling angiogenesis was further investigated with elaboration of the underlying molecular mechanism in human colon cancer cell and tumor xenograft. Results: AST decreased the protein level of VEGF and bFGF in HCT 116 colon cancer cells in a time- and dose-dependent manner. Among the Akt/mTOR signal transduction molecules being examined, AST caused PTEN upregulation, reduction in Akt phosphorylation and subsequent activation of mTOR. AST also suppressed the induction of HIF-1α and VEGF under CoCl
2 -mimicked hypoxia. These effects were intensified by combined treatment of AST with the mTOR inhibitor rapamycin. Despite this, our data also indicate that AST could attenuate cobalt chloride-evoked COX-2 activation, while such effect on COX-2 and its downstream target VEGF was intensified when indomethacin was concurrently treated. The anti-carcinogenic action of AST was further illustrated in HCT 116 xenografted athymic nude mice. AST significantly suppressed tumor growth and reduced serum VEGF level in vivo. In the tumor tissues excised from AST-treated animals, protein level of p-Akt, p-mTOR, VEGF, VEGFR1 and VEGFR2 was down-regulated. Immunohistochemistry has also revealed that AST effectively reduced the level of COX-2 in tumor sections when compared with that in untreated control. Conclusion: Taken together, these findings suggest that AST exerts anti-carcinogenic activity in colon cancer cells through modulation of mTOR signaling and downregulation of COX-2, which together reduce VEGF level in tumor cells that could potentially suppress angiogenesis. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
16. Astragalus saponins downregulate vascular endothelial growth factor under cobalt chloride-stimulated hypoxia in colon cancer cells
- Author
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Pui-Ching Law, Lok-Yi Chan, Joshua Ka-Shun Ko, and Kathy Ka-Wai Auyeung
- Subjects
Male ,Vascular Endothelial Growth Factor A ,medicine.medical_specialty ,Angiogenesis ,Colorectal cancer ,Down-Regulation ,Mice, Nude ,Biology ,digestive system ,chemistry.chemical_compound ,Mice ,Downregulation and upregulation ,Internal medicine ,Cell Line, Tumor ,medicine ,Astragalus saponins ,PTEN ,Animals ,Humans ,Hypoxia ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Mice, Inbred BALB C ,TOR Serine-Threonine Kinases ,lcsh:Other systems of medicine ,General Medicine ,Astragalus Plant ,Cobalt ,Akt/mTOR ,COX-2 ,Saponins ,lcsh:RZ201-999 ,medicine.disease ,VEGF ,digestive system diseases ,Colon cancer ,Vascular endothelial growth factor ,Gene Expression Regulation, Neoplastic ,Vascular endothelial growth factor A ,Endocrinology ,chemistry ,Complementary and alternative medicine ,Cyclooxygenase 2 ,Colonic Neoplasms ,Cancer research ,biology.protein ,Research Article ,Signal Transduction - Abstract
Background Our ongoing research has revealed that total saponins extracted from the medicinal herb Radix Astragali (AST) exhibits significant growth-inhibitory and proapoptotic effects in human cancer cells. In the present study, the potential of AST in controlling angiogenesis was further investigated with elaboration of the underlying molecular mechanism in human colon cancer cell and tumor xenograft. Results AST decreased the protein level of VEGF and bFGF in HCT 116 colon cancer cells in a time- and dose-dependent manner. Among the Akt/mTOR signal transduction molecules being examined, AST caused PTEN upregulation, reduction in Akt phosphorylation and subsequent activation of mTOR. AST also suppressed the induction of HIF-1α and VEGF under CoCl2-mimicked hypoxia. These effects were intensified by combined treatment of AST with the mTOR inhibitor rapamycin. Despite this, our data also indicate that AST could attenuate cobalt chloride-evoked COX-2 activation, while such effect on COX-2 and its downstream target VEGF was intensified when indomethacin was concurrently treated. The anti-carcinogenic action of AST was further illustrated in HCT 116 xenografted athymic nude mice. AST significantly suppressed tumor growth and reduced serum VEGF level in vivo. In the tumor tissues excised from AST-treated animals, protein level of p-Akt, p-mTOR, VEGF, VEGFR1 and VEGFR2 was down-regulated. Immunohistochemistry has also revealed that AST effectively reduced the level of COX-2 in tumor sections when compared with that in untreated control. Conclusion Taken together, these findings suggest that AST exerts anti-carcinogenic activity in colon cancer cells through modulation of mTOR signaling and downregulation of COX-2, which together reduce VEGF level in tumor cells that could potentially suppress angiogenesis.
- Full Text
- View/download PDF
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