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Fulltext Neuroprotective mechanisms of orientin against hydrogen peroxide-induced oxidative damage in SH-SY5Y cells

Lam, Kit Ying, Ling, Anna Pick Kiong, Sasmita, Andrew Octavian, Koh, Rhun Yian, Wong, Ying Pei, Voon, Kenny Gah Leong, et al.

Journal of Biochemistry, Microbiology and Biotechnology, 2018;6(1):10-18.
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Natural products or plant derivatives could be used to prevent or treat neurodegenerative diseases (ND). Oxidative stress has been highly implicated in the progression of ND;thus, this leads to the study on the effects of orientin in regulating Nrf2/Keap-1 redox signalling, PI3K/Akt survival and MAPK/ERK apoptosis pathways in the hydrogen peroxide (H2O2)-induced oxidative damage in SH-SY5Y cells. The cells were treated with half maximum non-toxic dose (½ MNTD) or maximum non-toxic dose (MNTD) of orientin and subsequently with H2O2. Cells were then subjected to the measurement of nitric oxide (NO), intracellular calcium (Ca2+), mitochondrial membrane potential (MMP) and annexin V/propidium iodide apoptosis assays. Regulation of the signalling pathways was analysed by Western blotting. Results showed that ½ MNTD of orientin reduced the NO levels. The intracellular Ca2+ level was also reduced by ½ MNTD and MNTD of orientin. The orientin treatment at ½ MNTD and MNTD restored the loss of MMP. Pre-treatment of orientin reduced the early and late apoptotic cells as well as necrotic cells. Orientin was found to up-regulate the Nrf2/Keap-1 and PI3K/Akt pathways whilst down-regulate the MAPK/ERK pathway. The findings from this study will be useful for the prevention of ND in the near future.
Madecassoside activates anti‑neuroinflammatory mechanisms by inhibiting lipopolysaccharide‑induced microglial inflammation

Sasmita AO, Ling APK, Voon KGL, Koh RY, Wong YP

Int J Mol Med, 2018 May;41(5):3033-3040.
PMID: 29436598 DOI: 10.3892/ijmm.2018.3479

Neurodegeneration is typically preceded by neuroinflammation generated by the nervous system to protect itself from tissue damage, however, excess neuroinflammation may inadvertently cause more harm to the surrounding tissues. Attenuating neuroinflammation with non‑steroidal anti‑inflammatory drugs can inhibit neurodegeneration. However, such treatments induce chronic side effects, including stomach ulcers. Madecassoside, a triterpene derived from Centella asiatica, is considered to be an alternative treatment of inflammation. In the present study, the anti‑neuroinflammatory properties of madecassoside were assessed in BV2 microglia cells, which were pre‑treated with madecassoside at a maximum non‑toxic dose (MNTD) of 9.50 µg/ml and a ½ MNTD of 4.75 µg/ml for 3 h and stimulated with 0.1 µg/ml lipopolysaccharide (LPS). The effect of madecassoside was assessed by determining reactive oxygen species (ROS) levels in all groups. Furthermore, the expression of pro‑ and anti‑neuroinflammatory genes and proteins were analyzed using reverse transcription‑quantitative polymerase chain reaction and western blotting, respectively. The results demonstrated that ROS levels in cells treated with the MNTD of madecassoside were significantly reduced compared with cells treated with LPS alone (P<0.05). The expression of pro‑neuroinflammatory genes, including inducible nitric oxide synthase, cyclooxygenase‑2, signal transducer and activator of transcription 1 and nuclear factor‑κB, were significantly downregulated in a dose‑independent manner following treatment with madecassoside. Conversely, the anti‑neuroinflammatory component heme oxygenase 1 was significantly upregulated by 175.22% in the MNTD‑treated group, compared with cells treated with LPS alone (P<0.05). The gene expression profiles of pro‑ and anti‑inflammatory genes were also consistent with the results of western blotting. The results of the present study suggest that madecassoside may be a potent anti‑neuroinflammatory agent. The antioxidative properties of madecassoside, which serve a major role in anti‑neuroinflammation, indicate that this compound may be a functional natural anti‑neuroinflammatory agent, therefore, further in vivo or molecular studies are required.
Cancer Antibody Engineering: Comparison of Mammalian, Yeast, Bacterial, Plants, Cell-free and Hybridoma Expression Systems

Ng MG, Tan HY, Ng PY, Koh RY, Voon KGL, Chye SM

Curr Pharm Biotechnol, 2024 Jul 12.
PMID: 39005118 DOI: 10.2174/0113892010307146240626080746

BACKGROUND: Cancer is a significant issue worldwide. Generally, commercially available treatments, such as surgery, radiotherapy, and chemotherapy, are associated with undesirable complications. Hence, immunotherapy serves as a crucial alternative to those treatment options.
OBJECTIVE: This modality is aimed to boost the immune system through the application of engineered antibodies, which can be produced using recombinant DNA technology.
RESULTS: The discussion of the technologies leads to an introduction of the single-chain variable fragment (scFv). Thereafter, the advantages, disadvantages, and challenges associated with different expression systems, such as mammalian cells, yeast cells, bacterial cells, plant cells, and phage display were discussed comprehensively.
CONCLUSION: Furthermore, conventional approaches such as hybridoma and modern approaches such as cell-free protein synthesis (CFPS) and simple colony assays are included. In short, this article has compiled evidence relating to each display system and may serve as a reference for those who aim to explore antibody engineering using one of the methods listed in this article.
The Mechanism of Action of Salsolinol in Brain: Implications in Parkinson's Disease

Voon SM, Ng KY, Chye SM, Ling APK, Voon KGL, Yap YJ, et al.

CNS Neurol Disord Drug Targets, 2020;19(10):725-740.
PMID: 32881676 DOI: 10.2174/1871527319666200902134129

1-Methyl-1,2,3,4-tetrahydroisoquinoline-6,7-diol, commonly known as salsolinol, is a compound derived from dopamine. It was first discovered in 1973 and has gained attention for its role in Parkinson's disease. Salsolinol and its derivatives were claimed to play a role in the pathogenesis of Parkinson's disease as a neurotoxin that induces apoptosis of dopaminergic neurons due to its structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its ability to induce Parkinsonism. In this article, we discussed the biosynthesis, distribution and blood-brain barrier permeability of salsolinol. The roles of salsolinol in a healthy brain, particularly the interactions with enzymes, hormone and catecholamine, were reviewed. Finally, we discussed the involvement of salsolinol and its derivatives in the pathogenesis of Parkinson's disease.
Fulltext Screening of Streptococcus suis in swine workers of selected states in Peninsular Malaysia

Lee CY, Zakaria Z, Selvarajah GT, Mustaffa-Kamal F, Voon KGL, Fong MWC, et al.

Vet World, 2024 Jan;17(1):1-7.
PMID: 38406356 DOI: 10.14202/vetworld.2024.1-7

BACKGROUND AND AIM: Streptococcus suis is a zoonotic pathogen that is highly associated with contact between live pigs and raw pig material. In view of the recent reports of human infections in Malaysia, epidemiological data on the status of S. suis in the human population, especially among people working closely with pigs and/or raw pork, should be provided. The aim of this study was to detect S. suis among individuals working in the swine industry in several major pig production areas in Peninsular Malaysia.
MATERIALS AND METHODS: Demographic information, exposure determinants, and oral swabs were collected from swine personnel, including farmers, butchers, and veterinarians. Oral swabs were subjected to bacterial isolation and conventional polymerase chain reaction (PCR) assays for S. suis detection.
RESULTS: The study included 40 participants working in the swine industry, with a predominant representation of males (62.5%) and Malaysian Chinese individuals (60.0%) who consumed pork (92.5%). Notably, none of the participants reported consuming raw or partially cooked pork. In spite of their occupational exposure risk, none of the oral swabs showed positive results for S. suis infection.
CONCLUSION: To the best of our knowledge, this is the first report and detection study of S. suis using oral swabs obtained from swine personnel in Peninsular Malaysia.
Fulltext Detection of respiratory viruses in adults with suspected COVID-19 in Kuala Lumpur, Malaysia

Chong YM, Chan YF, Jamaluddin MFH, Hasan MS, Pang YK, Ponnampalavanar S, et al.

J Clin Virol, 2021 Dec;145:105000.
PMID: 34739838 DOI: 10.1016/j.jcv.2021.105000

BACKGROUND: Reports of co-circulation of respiratory viruses during the COVID-19 pandemic and co-infections with SARS-CoV-2 vary. However, limited information is available from developing countries.
OBJECTIVES: We aimed to investigate the incidence of respiratory viruses in adult patients with suspected COVID-19 in Kuala Lumpur, Malaysia.
STUDY DESIGN: We collected 198 respiratory samples from adult patients hospitalized with suspected COVID-19 in a single teaching hospital in Kuala Lumpur in February-May 2020 and tested combined oro-nasopharyngeal swabs with the NxTAG Respiratory Pathogen Panel (Luminex) and Allplex RV Essential (Seegene) assays. Forty-five negative samples further underwent viral metagenomics analysis.
RESULTS: Of the 198 samples, 74 (37.4%) had respiratory pathogens, including 56 (28.3%) with SARS-CoV-2 and 18 (9.1%) positive for other respiratory pathogens. There were five (2.5%) SARS-CoV-2 co-infections, all with rhinovirus/enterovirus. Three samples (6.7%; 3/45) had viruses identified by metagenomics, including one case of enterovirus D68 and one of Saffold virus genotype 6 in a patient requiring ICU care. Most of the COVID-19 patients (91.1%; 51/56) had mild symptoms but 5.4% (3/56) died.
CONCLUSION: During the early COVID-19 period, common respiratory viruses other than SARS-CoV-2 only accounted for 9.1% of hospitalization cases with ARI and co-infections with SARS-CoV-2 were rare. Continued surveillance is important to understand the impact of COVID-19 and its associated public health control measures on circulation of other respiratory viruses. Metagenomics can identify unexpected or rare pathogens, such as Saffold virus, which is rarely described in adults.