Displaying publications 1 - 20 of 45 in total

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  1. Wang H, Vidyadaran S, Mohd Moklas MA, Baharuldin MTH
    PMID: 29358962 DOI: 10.1155/2017/2623163
    Objective: To explore the effect of Ficus deltoidea (FD) aqueous extracts on the release of tumor necrosis factor-α (TNF-α), the expression of CD40, and the morphology of microglial cells in lipopolysaccharide- (LPS-) activated BV2 cells.

    Methods: The cytotoxicity of FD extract was assessed by MTS solution. BV2 cells were divided into 5 experimental groups, intervened, respectively, by FD (4 mg/mL) and LPS + FD (0, 1, 2, and 4 mg/mL). Besides, a blank control group was set up without any intervention. TNF-α release was assessed by enzyme linked immunosorbent assay (ELISA). The expression of CD40 was examined by flow cytometry. Immunocytochemical staining was used to show the morphology of BV2 cells.

    Results: FD extract of different concentrations (1, 2, and 4 mg/mL) had no significant toxic effects on the BV2 cells. FD suppressed the activation of microglia in morphology and reduced TNF-α production and expression of CD40 induced by LPS.

    Conclusion: FD extract has a therapeutic potential against neuroinflammatory diseases.

  2. Vidyadaran S, Ooi YY, Subramaiam H, Badiei A, Abdullah M, Ramasamy R, et al.
    Cell Immunol, 2009;259(1):105-10.
    PMID: 19577228 DOI: 10.1016/j.cellimm.2009.06.005
    A challenge for studies involving microglia cultures is obtaining sufficient cells for downstream experiments. Macrophage colony-stimulating factor (M-CSF) has been used to improve yield of microglia in culture. However, the effects of M-CSF on activation profiles of microglia cultures are still unclear. Microglia activation is characterised by upregulation of co-stimulatory molecules and an inflammatory phenotype. The aim of this study is to demonstrate whether M-CSF supplementation alters microglial responses in resting and activated conditions. Microglia derived from mixed glia cultures and the BV-2 microglia cell line were cultivated with/without M-CSF and activated with lipopolysaccharide (LPS) and beta amyloid (Abeta). We show M-CSF expands primary microglia without affecting microglial responses to LPS and Abeta, as shown by the comparable expression of MHC class II and CD40 to microglia grown without this growth factor. M-CSF supplementation in BV-2 cells had no effect on nitric oxide (NO) production. Therefore, M-CSF can be considered for improving microglia yield in culture without introducing activation artefacts.
  3. Vellasamy S, Sandrasaigaran P, Vidyadaran S, George E, Ramasamy R
    World J Stem Cells, 2012 Jun 26;4(6):53-61.
    PMID: 22993662
    To explore the feasibility of placenta tissue as a reliable and efficient source for generating mesenchymal stem cells (MSC).
  4. Vellasamy S, Sandrasaigaran P, Vidyadaran S, Abdullah M, George E, Ramasamy R
    Cell Biol Int, 2013 Mar;37(3):250-6.
    PMID: 23364902 DOI: 10.1002/cbin.10033
    Mesenchymal stem cells (MSC) generated from human umbilical cord (UC-MSC) and placenta (PLC-MSC) were assessed and compared for their immunomodulatory function on T cells proliferation by analysis of the cell cycle. Mitogen stimulated or resting T cells were co-cultured in the presence or absence of MSC. T-cell proliferation was assessed by tritiated thymidine ((3) H-TdR) assay and the mechanism of inhibition was examined bycell cycle and apoptosis assay. Both UC-MSC and PLC-MSC profoundly inhibited the proliferation of T-cell, mainly via cell-to-cell contact. MSC-mediated anti-proliferation does not lead to apoptosis,but prevented T cells from entering S phase and they therefore accumulated in the G(0) /G(1) phases. The anti-proliferative activity of MSC was related to this cell cycle arrest of T-cell. UC-MSC produced a greater inhibition than PLC-MSC in all measured parameters.
  5. Tong CK, Vellasamy S, Tan BC, Abdullah M, Vidyadaran S, Seow HF, et al.
    Cell Biol Int, 2011 Mar;35(3):221-6.
    PMID: 20946106 DOI: 10.1042/CBI20100326
    MSCs (mesenchymal stem cells) promise a great potential for regenerative medicine due to their unique properties of self-renewal, high plasticity, modulation of immune response and the flexibility for genetic modification. Therefore, the increasing demand for cellular therapy necessitates a larger-scale production of MSC; however, the technical and ethical issues had put a halt on it. To date, studies have shown that MSC could be derived from human UC (umbilical cord), which is once considered as clinical waste. We have compared the two conventional methods which are classic enzymatic digestion and explant method with our newly tailored enzymatic-mechanical disassociation method to generate UC-MSC. The generated UC-MSCs from the methods above were characterized based on their immunophenotyping, early embryonic transcription factors expression and mesodermal differentiation ability. Our results show that enzymatic-mechanical disassociation method increase the initial nucleated cell yield greatly (approximately 160-fold) and maximized the successful rate of UC-MSC generation. Enzymatic-mechanical disassociation-derived UC-MSC exhibited fibroblastic morphology and surface markers expression of CD105, CD73, CD29, CD90 and MHC class I. Furthermore, these cells constitutively express early embryonic transcription factors (Nanog, Oct-4, Sox-2 and Rex-1), as confirmed by RT-PCR, indicating their multipotency and high self-renewal capacity. They are also capable of differentiating into osteoblasts and adipocytes when given an appropriate induction. The present study demonstrates a new and efficient approach in generating MSC from UC, hence serving as ideal alternative source of mesenchymal stem cell for clinical and research use.
  6. Tong CK, Vidyadaran S
    Exp Biol Med (Maywood), 2016 Sep;241(15):1669-75.
    PMID: 27555616 DOI: 10.1177/1535370216664430
    Microglia begin colonizing the developing brain as early as embryonic day 9, prior to the emergence of neurons and other glia. Their ontogeny is also distinct from other central nervous system cells, as they derive from yolk sac hematopoietic progenitors and not neural progenitors. In this review, we feature these unique characteristics of microglia and assess the spatiotemporal similarities between microglia colonization of the central nervous system and embryonic neurogenesis. We also infer to existing evidence for microglia function from embryonic through to postnatal neurodevelopment to postulate roles for microglia in neurogenesis.
  7. Tan SW, Ramasamy R, Abdullah M, Vidyadaran S
    Cell Immunol, 2011;271(2):205-9.
    PMID: 21839427 DOI: 10.1016/j.cellimm.2011.07.012
    Anti-inflammatory actions of the vitamin E fragment tocotrienol have not been described for microglia. Here, we screened palm α-, γ- and δ-tocotrienol isoforms and Tocomin® 50% (contains spectrum of tocotrienols and tocopherols) for their ability to limit nitric oxide (NO) production by BV2 microglia. Microglia were treated with varying doses of tocotrienols for 24h and stimulated with 1 μg/ml lipopolysaccharide (LPS). All tocotrienol isoforms reduced NO release by LPS-stimulated microglia, with 50 μM being the most potent tocotrienol dose. Of the isoforms tested, δ-tocotrienol lowered NO levels the most, reducing NO by approximately 50% at 48 h post-LPS treatment (p
  8. Tan SW, Israf Ali DAB, Khaza'ai H, Wong JW, Vidyadaran S
    Cell Immunol, 2020 11;357:104200.
    PMID: 32979761 DOI: 10.1016/j.cellimm.2020.104200
    Tocopherols long dominated studies on vitamin E, although interest has shifted to tocotrienols. It was previously shown that δ-tocotrienol derived from palm oil reduced nitric oxide released by BV2 microglia as early as 18 h after lipopolysaccharide stimulation. The current study measured δ-tocotrienol uptake by BV2 over a 24 h incubation period and its anti-inflammatory effects on primary microglia. Uptake of 17.5 μg/mL δ-tocotrienol by BV2 microglia began as early as 5 min and rose steeply to 21 ± 3% of the amount administered at 24 h. The amount of δ-tocotrienol retained in the lipopolysaccharide-stimulated microglia at 24 h was 14 ± 2%, with no substantial difference seen in unstimulated microglia. The same δ-tocotrienol regimen reduced nitric oxide levels by 82% at 24 h after lipopolysaccharide stimulation (p 
  9. Seow SL, Naidu M, Sabaratnam V, Vidyadaran S, Wong KH
    Int J Med Mushrooms, 2017;19(5):405-418.
    PMID: 28845770 DOI: 10.1615/IntJMedMushrooms.v19.i5.30
    In Malaysia and China, the sclerotium of Lignosus rhinocerotis is used by local communities and traditional medicine practitioners as a general tonic and remedy to treat a variety of ailments, including inflammation-associated disorders. In this study, 10 samples from different preparations of L. rhinocerotis sclerotium, including a hot aqueous extract (HAE), an ethanol extract (EE), fractions from the HAE and EE, and crude polysaccharides, were tested for their in vitro cytotoxic and nitric oxide (NO) inhibitory activities in lipopolysaccharide (LPS)--stimulated BV2 microglia. Of the 10 samples tested, HAE was the least cytotoxic toward BV2 microglia, with a half-maximal inhibitory concentration of 176.23 ± 2.64 mg/mL at 24 hours of incubation and 20.01 ± 1.69 mg/ mL at 48 hours of incubation. The inhibition of NO production was explored by pretreatment of BV2 microglia with samples at 2 incubation time points (4 and 24 hours) before the stimulation by LPS for 24 hours. After 24 hours of pretreatment, 8 of the 10 samples inhibited NO production by 50% or more, and cytotoxic effects were not observed. Among the 8 active samples, 500 µg/mL of HAE, 250 µg/mL of an n-butanol fraction of the HAE, and 250 µg/mL of an ethyl acetate fraction of HAE showed maximum inhibition of NO production by 88.95%, 86.50%, and 85.93%, respectively. These results suggest that the L. rhinocerotis sclerotium may contain secondary metabolites that have the potential to inhibit NO production.
  10. Selvaraju TR, Khaza'ai H, Vidyadaran S, Abd Mutalib MS, Vasudevan R
    Bosn J Basic Med Sci, 2014 Nov 16;14(4):195-204.
    PMID: 25428670 DOI: 10.17305/bjbms.2014.4.91
    Tocotrienol rich fraction (TRF) is an extract of palm oil, which consists of 25% alpha tocopherol (α-TCP) and 75% tocotrienols. TRF has been shown to possess potent antioxidant, anti-inflammatory, anticancer, neuroprotection, and cholesterol lowering activities. Glutamate is the main excitatory amino acid neurotransmitter in the central nervous system of mammalian, which can be excitotoxic, and it has been suggested to play a key role in neurodegenerative disorders like Parkinson's and Alzheimer's diseases. In this present study, the effects of vitamin E (TRF and α-TCP) in protecting astrocytes against glutamate injury were elucidated. Astrocytes induced with 180 mM of glutamate lead to significant cell death. However, glutamate mediated cytotoxicity was diminished via pre and post supplementation of TRF and α-TCP. Hence, vitamin E acted as a potent antioxidant agent in recovering mitochondrial injury due to elevated oxidative stress, and enhanced better survivability upon glutamate toxicity.
  11. Sarmadi VH, Tong CK, Vidyadaran S, Abdullah M, Seow HF, Ramasamy R
    Med J Malaysia, 2010 Sep;65(3):209-14.
    PMID: 21939170
    We have previously shown that mesenchymal stem cells (MSC) inhibit tumour cell proliferation, thus promising a novel therapy for treating cancers. In this study, MSC were generated from human bone marrow samples and characterised based on standard immunophenotyping. When MSC were co-cultured with BV173 and Jurkat tumour cells, the proliferation of tumour cells were profoundly inhibited in a dose dependent manner mainly via cell to cell contact interaction. Further cell cycle analysis reveals that MSC arrest tumour cell proliferation in G0/G1 phase of cell cycle thus preventing the entry of tumour cells into S phase of cell cycle.
  12. Sandrasaigaran P, Algraittee SJR, Ahmad AR, Vidyadaran S, Ramasamy R
    Cytotechnology, 2018 Jun;70(3):1037-1050.
    PMID: 29497876 DOI: 10.1007/s10616-017-0182-4
    Mesenchymal stem cells (MSCs) exert potent immuno-regulatory activities on various immune cells and also differentiate into various mesodermal lineages besides retaining a distinct self-renewal ability. Such exclusive characteristics had enabled MSCs to be recognised as an ideal source for cell-based treatment in regenerative medicine and immunotherapy. Thus, considering MSCs for treating degenerative disease of organs with limited regenerative potential such as cartilage would serve as an ideal therapy. This study explored the feasibility of generating human cartilage-derived MSCs (hC-MSCs) from sports injured patients and characterised based on multipotent differentiation and immunosuppressive activities. Cartilage tissues harvested from a non-weight bearing region during an arthroscopy procedure were used to generate MSCs. Despite the classic morphology of fibroblast-like cells and a defined immunophenotyping, MSCs expressed early embryonic transcriptional markers (SOX2, REX1, OCT4 and NANOG) and differentiated into chondrocytes, adipocytes and osteocytes when induced accordingly. Upon co-culture with PHA-L activated T-cells, hC-MSCs suppressed the proliferation of the T-cells in a dose-dependent manner. Although, hC-MSCs did not alter the activation profile of T cells significantly, yet prevented the entering of activated T cells into S phase of the cell cycle by cell cycle arrest. The present study has strengthened the evidence of tissue-resident mesenchymal stem cells in human cartilage tissue. The endogenous MSCs could be an excellent tool in treating dysregulated immune response that associated with cartilage since hC-MSCs exerted both immunosuppressive and regenerative capabilities.
  13. Rati Selvaraju T, Khaza'ai H, Vidyadaran S, Sokhini Abd Mutalib M, Ramachandran V, Hamdan Y
    Int J Vitam Nutr Res, 2014;84(3-4):140-51.
    PMID: 26098478 DOI: 10.1024/0300-9831/a000201
    Glutamate is the major mediator of excitatory signals in the mammalian central nervous system. Extreme amounts of glutamate in the extracellular spaces can lead to numerous neurodegenerative diseases. We aimed to clarify the potential of the following vitamin E isomers, tocotrienol-rich fraction (TRF) and α-tocopherol (α-TCP), as potent neuroprotective agents against glutamate-induced injury in neuronal SK-N-SH cells. Cells were treated before and after glutamate injury (pre- and post-treatment, respectively) with 100-300 ng/ml TRF/α-TCP. Exposure to 120 mM glutamate significantly reduced cell viability to 76% and 79% in the pre- and post-treatment studies, respectively; however, pre- and post-treatment with TRF/α-TCP attenuated the cytotoxic effect of glutamate. Compared to the positive control (glutamate-injured cells not treated with TRF/α-TCP), pre-treatment with 100, 200, and 300 ng/ml TRF significantly improved cell viability following glutamate injury to 95.2%, 95.0%, and 95.6%, respectively (p<0.05).The isomers not only conferred neuroprotection by enhancing mitochondrial activity and depleting free radical production, but also increased cell viability and recovery upon glutamate insult. Our results suggest that vitamin E has potent antioxidant potential for protecting against glutamate injury and recovering glutamate-injured neuronal cells. Our findings also indicate that both TRF and α-TCP could play key roles as anti-apoptotic agents with neuroprotective properties.
  14. Ramasamy, R., Krishna, K., Maqbool, M., Vellasamy, S., Sarmadi, V. H., Abdullah, M., et al.
    MyJurnal
    Objective: Mesenchymal stem cells (MSC) are multipotent, non-haematopoietic stem cells that are
    capable of differentiating into different varieties of mature cell types such as osteoblasts, chondrocytes, adipocytes, and myoblasts. There is abundant evidence showing that MSC not only affect the differentiation of haematopoietic progenitors, but also the function of mature cells like lymphocytes and neutrophils. However the effect of MSC on neutrophil function and its responses is not well studied. Therefore, this study was conducted to assess the effect of MSC on neutrophil nitric oxide production. Method: Neutrophils from heparanised venous blood were isolated using Ficoll-Hypaque density gradient centrifugation followed by Dextran sedimentation and red blood cell (RBC) lysis. Isolated neutrophils were on average of 97% purity as determined by morphologic analysis. MSC were generated from human bone marrow and characterised by immunophenotyping (monoclonal antibodies CD105, CD73 and CD34) using a flowcytometer. In order to test the effects of MSC on neutrophil function, isolated neutrophils were co-cultured in the presence or absence of MSC at different ratios for 24 and 48 hours. The amount of nitric oxide released was used as an indication of oxidative burst and measured using the Griess assay. Result: The results indicate that MSC neither elevate the NO level when cocultured with resting neutrophils nor alone. However MSC profoundly inhibit the secretion of nitric oxide in PMA stimulated neutrophils after 24hr of incubation. Conclusion: MSC exert an immunomodulatory effect on neutrophil by suppressing neutrophil oxidative burst in vitro.
  15. Ramasamy R, Tong CK, Seow HF, Vidyadaran S, Dazzi F
    Cell Immunol, 2008 Feb;251(2):131-6.
    PMID: 18502411 DOI: 10.1016/j.cellimm.2008.04.009
    Mesenchymal stem cells (MSC) are non-haematopoietic stem cells that are capable of differentiating into tissues of mesodermal origin. MSC play an important role in supporting the development of fetal and adult haematopoiesis. More recently, MSC have also been found to exhibit inhibitory effect on T cell responses. However, there is little information on the mechanism of this immunosuppression and our study addresses this issue by targeting T cell functions at various level of immune responses. We have generated MSC from human adult bone marrow (BM) and investigated their immunoregulatory function at different phases of T cell responses. MSC showed the ability to inhibit mitogen (CD3/CD28 microbeads)-activated T cell proliferation in a dose-dependent manner. In order to evaluate the specificity of this immunosuppression, the proliferation of CD4(+) and CD8(+) cells were measured. MSC equally inhibit CD4(+) and CD8(+) subpopulations of T cells in response to PHA stimulation. However, the antiproliferative effect of MSC is not due to the inhibition of T cell activation. The expression of early activation markers of T cells, namely CD25 and CD69 were not significantly altered by MSC at 24, 48 and 72h. Furthermore, the immunosuppressive effect of MSC mainly targets T cell proliferation rather than their effector function since cytotoxicity of T cells is not affected. This work demonstrates that the immunosuppressive effect of MSC is exclusively a consequence of an anti-proliferative activity, which targets T cells of different subpopulations. For this reason, they have the potential to be exploited in the control of unwanted immune responses such as graft versus host disease (GVHD) and autoimmunity.
  16. Pan ML, Ahmad Puzi NN, Ooi YY, Ramasamy R, Vidyadaran S
    Biomedicines, 2023 Sep 27;11(10).
    PMID: 37893022 DOI: 10.3390/biomedicines11102648
    (1) Background: The latest research illustrates that microglia phenotype is not the binary 'resting' and 'activated' profiles. Instead, there is wide diversity in microglia states. Similarly, when testing different stimulation protocols for BV2 microglia, we discovered differences in the response of the cells in terms of the production of intracellular ROS (iROS), nitric oxide (NO), CD40 expression, and migratory capacity. (2) Methods: BV2 microglia were treated with single interferon gamma (IFN-γ) stimulation, LPS/IFN-γ co-stimulation, and priming with IFN-γ followed by stimulation with LPS for 24 h. The responses of BV2 microglia were then assessed using the H2DCFDA test for iROS, the Griess assay for NO, immunophenotyping for CD40/CD11b/MHC II, and migration using a transwell apparatus. (3) Results: Single stimulation with IFN-γ induced NO but not ROS in BV2 microglia. Co-stimulation with LPS200IFN-γ2.5 induced a higher iROS production (a 9.2-fold increase) and CD40 expression (28031 ± 8810.2 MFI), compared to priming with primedIFN-γ50LPS100 (a 4.0-fold increase in ROS and 16764 ± 1210.8 MFI of CD40). Co-stimulation also induced cell migration. On the other hand, priming BV2 microglia (primedIFN-γ50LPS100) resulted in a higher NO production (64 ± 1.4 µM) compared to LPS200IFN-γ2.5 co-stimulation (44 ± 1.7 µM). Unexpectedly, priming inhibited BV2 migration. (4) Conclusions: Taken together, the findings from this project reveal the ability of co-stimulation and priming in stimulating microglia into an inflammatory phenotype, and the heterogeneity of microglia responses towards different stimulating approaches.
  17. Ooi YY, Ramasamy R, Vidyadaran S
    Med J Malaysia, 2008 Jul;63 Suppl A:65-6.
    PMID: 19024986
    Classically, MSC are identified by a CD45-CD106+ phenotype. In this study, we found that mouse MSC achieve this characteristic phenotype only at later passages. With increasing passages, CD45 (hematopoietic marker) expression shifts to negativity, whereas CD106 (vascular cell adhesion molecule-1) expression becomes increasingly positive. These results demonstrate that MSC cells cultured from mouse bone marrow acquire a classical MSC immunophenotype (CD45-CD106+) in later passages.
  18. Ooi YY, Rahmat Z, Jose S, Ramasamy R, Vidyadaran S
    World J Stem Cells, 2013 Jan 26;5(1):34-42.
    PMID: 23362438 DOI: 10.4252/wjsc.v5.i1.34
    To assess the capacity to isolate and expand mesenchymal stem cells (MSC) from bone marrow of CBA/Ca, ICR and Balb/c mice.
  19. Ooi YY, Ramasamy R, Rahmat Z, Subramaiam H, Tan SW, Abdullah M, et al.
    Int Immunopharmacol, 2010 Dec;10(12):1532-40.
    PMID: 20850581 DOI: 10.1016/j.intimp.2010.09.001
    The immunoregulatory properties of mesenchymal stem cells (MSC) have been demonstrated on a wide range of cells. Here, we describe the modulatory effects of mouse bone marrow-derived MSC on BV2 microglia proliferation rate, nitric oxide (NO) production and CD40 expression. Mouse bone marrow MSC were co-cultured with BV2 cells at various seeding density ratios and activated with lipopolysaccharide (LPS). We show that MSC exert an anti-proliferative effect on microglia and are potent producers of NO when stimulated by soluble factors released by LPS-activated BV2. MSC suppressed proliferation of both untreated and LPS-treated microglia in a dose-dependent manner, significantly reducing BV2 proliferation at seeding density ratios of 1:0.2 and 1:0.1 (p
  20. Omar Zaki SS, Kanesan L, Leong MYD, Vidyadaran S
    Cell Biol Int, 2019 Oct;43(10):1201-1204.
    PMID: 30811086 DOI: 10.1002/cbin.11122
    Our work cautions against the use of serum-supplemented culture media in a transwell migration assay when using chemoattractants other than FBS. At 24 h, a 5% foetal bovine serum (FBS) gradient caused BV2 microglia to migrate toward the lower compartment of the transwell apparatus. Interestingly, FBS-supplemented media in the absence of a gradient also resulted in notable microglia migration. Serum can therefore confound the interpretation of a transwell migration assay when another chemoattractant is used.
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