Displaying publications 1 - 20 of 71 in total

  1. Tan JK, Jaafar F, Makpol S
    BMC Complement Altern Med, 2018 Nov 29;18(1):314.
    PMID: 30497457 DOI: 10.1186/s12906-018-2383-6
    BACKGROUND: Replicative senescence of human diploid fibroblasts (HDFs) has been used as a model to study mechanisms of cellular aging. Gamma-tocotrienol (γT3) is one of the members of vitamin E family which has been shown to increase proliferation of senescent HDFs. However, the modulation of protein expressions by γT3 in senescent HDFs remains to be elucidated. Therefore, this study aimed to determine the differentially expressed proteins (DEPs) in young and senescent HDFs; and in vehicle- and γT3-treated senescent HDFs using label-free quantitative proteomics.

    METHODS: Whole proteins were extracted and digested in-gel with trypsin. Peptides were detected by Orbitrap liquid chromatography mass spectrometry. Mass spectra were identified and quantitated by MaxQuant software. The data were further filtered and analyzed statistically using Perseus software to identify DEPs. Functional annotations of DEPs were performed using Panther Classification System.

    RESULTS: A total of 1217 proteins were identified in young and senescent cells, while 1218 proteins in vehicle- and γT3-treated senescent cells. 11 DEPs were found in young and senescent cells which included downregulation of platelet-derived growth factor (PDGF) receptor beta and upregulation of tubulin beta-2A chain protein expressions in senescent cells. 51 DEPs were identified in vehicle- and γT3-treated senescent cells which included upregulation of 70 kDa heat shock protein, triosephosphate isomerase and malate dehydrogenase protein expressions in γT3-treated senescent cells.

    CONCLUSIONS: PDGF signaling and cytoskeletal structure may be dysregulated in senescent HDFs. The pro-proliferative effect of γT3 on senescent HDFs may be mediated through the stimulation of cellular response to stress and carbohydrate metabolism. The expressions and roles of these proteins in relation to cellular senescence are worth further investigations. Data are available via ProteomeXchange with identifier PXD009933.

  2. Jaafar F, Abdullah A, Makpol S
    Sci Rep, 2018 Jul 11;8(1):10471.
    PMID: 29992988 DOI: 10.1038/s41598-018-28708-z
    Tocotrienol-rich fraction (TRF) is palm vitamin E that consists of tocopherol and tocotrienol. TRF is involved in important cellular regulation including delaying cellular senescence. A key regulator of cellular senescence, Sirtuin 1 (SIRT1) is involved in lipid metabolism. Thus, SIRT1 may regulate vitamin E transportation and bioavailability at cellular level. This study aimed to determine the role of SIRT1 on cellular uptake and bioavailability of TRF in human diploid fibroblasts (HDFs). SIRT1 gene in young HDFs was silenced by small interference RNA (siRNA) while SIRT1 activity was inhibited by sirtinol. TRF treatment was given for 24 h before or after SIRT1 inhibition. Cellular concentration of TRF isomers was determined according to the time points of before and after TRF treatment at 0, 24, 48, 72 and 96 h. Our results showed that all tocotrienol isomers were significantly taken up by HDFs after 24 h of TRF treatment and decreased 24 h after TRF treatment was terminated but remained in the cell up to 72 h. The uptake of α-tocopherol, α-tocotrienol and β-tocotrienol was significantly higher in senescent cells as compared to young HDFs indicating higher requirement for vitamin E in senescent cells. Inhibition of SIRT1 gene increased the uptake of all tocotrienol isomers but not α-tocopherol. However, SIRT1 inhibition at protein level decreased tocotrienol concentration. In conclusion, SIRT1 may regulate the cellular uptake and bioavailability of tocotrienol isomers in human diploid fibroblast cells while a similar regulation was not shown for α-tocopherol.
  3. Roslan NH, Makpol S, Mohd Yusof YA
    Asian Pac. J. Cancer Prev., 2019 May 25;20(5):1309-1319.
    PMID: 31127882
    BACKGROUND: Colorectal cancer (CRC) is one of the major causes of morbidity and mortality. According to National Cancer Registry, the incidence of colorectal cancer in Peninsular Malaysia increases with age. The incidence is highest among Chinese population but lower among Indians and Malays. Many reviews have suggested that obesity may be associated with a higher risk (>50%) of colorectal cancer.
    METHODS: This study collects a comprehensive data from the literature review available from respective journals on dietary intervention and the chemo-protective mechanisms of a few natural resources in obesity -associated colon cancer based on previous and current studies.
    RESULTS: In obesity-associated colon cancer, the genes of interest and pathways that are mainly involved include NFκB, P13K/Akt, and MAPK pathways, and FTO, leptin, Cyclin D, MMPs, and STAT3 genes. Dietary modification is one of the alternative steps in early prevention of colon cancer. It has been proposed that the components present in certain foods may have the ability to protect against many diseases including the prevention of cancer.
    CONCLUSION: There are many factors that lead to obesity-associated colon cancer and the mechanisms behind it is still undergoing intensive research. This review aims to scrutinize research as well as reviews that have been previously reported on obesity associated colorectal cancer and the beneficial effects of including antioxidants-rich foods such as vegetables and fruits in the diet to reduce the risk of obesity associated colorectal cancer.
    KEYWORDS: Obesity; colon cancer; pathways; natural phytochemicals
  4. Mohd Sahardi NFN, Makpol S
    PMID: 31531114 DOI: 10.1155/2019/5054395
    Currently, the age of the population is increasing as a result of increased life expectancy. Ageing is defined as the progressive loss of physiological integrity, which can be characterized by functional impairment and high vulnerability to various types of diseases, such as diabetes, hypertension, Alzheimer's disease (AD), Parkinson's disease (PD), and atherosclerosis. Numerous studies have reported that the presence of oxidative stress and inflammation contributes to the development of these diseases. In general, oxidative stress could induce proinflammatory cytokines and reduce cellular antioxidant capacity. Increased oxidative stress levels beyond the production of antioxidant agents cause oxidative damage to biological molecules, including DNA, protein, and carbohydrates, which affects normal cell signalling, cell growth, differentiation, and apoptosis and leads to disease pathogenesis. Since oxidative stress and inflammation contribute to these diseases, ginger (Zingiber officinale Roscoe) is one of the potential herbs that can be used to reduce the level of oxidative stress and inflammation. Ginger consists of two major active components, 6-gingerol and 6-shogaol, which are essential for preventing oxidative stress and inflammation. Thus, this paper will review the effects of ginger on ageing and degenerative diseases, including AD, PD, type 2 diabetes mellitus (DM), hypertension, and osteoarthritis.
  5. Saberbaghi T, Abbasian F, Mohd Yusof YA, Makpol S
    PMID: 23573154 DOI: 10.1155/2013/780504
    In this study, the effects of Chlorella vulgaris (CV) on replicative senescence of human diploid fibroblasts (HDFs) were investigated. Hot water extract of CV was used to treat HDFs at passages 6, 15, and 30 which represent young, presenescence, and senescence ages, respectively. The level of DNA damage was determined by comet assay while apoptosis and cell cycle profile were determined using FACSCalibur flow cytometer. Our results showed direct correlation between increased levels of damaged DNA and apoptosis with senescence in untreated HDFs (P < 0.05). Cell cycle profile showed increased population of untreated senescent cells that enter G0/G1 phase while the cell population in S phase decreased significantly (P < 0.05). Treatment with CV however caused a significant reduction in the level of damaged DNA and apoptosis in all age groups of HDFs (P < 0.05). Cell cycle analysis showed that treatment with CV increased significantly the percentage of senescent HDFs in S phase and G2/M phases but decreased the population of cells in G0/G1 phase (P < 0.05). In conclusion, hot water extract of Chlorella vulgaris effectively decreased the biomarkers of ageing, indicating its potential as an antiageing compound.
  6. Makpol S, Abdul Rahim N, Hui CK, Ngah WZ
    Oxid Med Cell Longev, 2012;2012:785743.
    PMID: 22919441 DOI: 10.1155/2012/785743
    In this study, we determined the molecular mechanism of γ-tocotrienol (GTT) in preventing cellular aging by focusing on its anti-apoptotic effect in stress-induced premature senescence (SIPS) model of human diploid fibroblasts (HDFs). Results obtained showed that SIPS exhibited senescent-phenotypic characteristic, increased expression of senescence-associated β-galactosidase (SA β-gal) and promoted G(0)/G(1) cell cycle arrest accompanied by shortening of telomere length with decreased telomerase activity. Both SIPS and senescent HDFs shared similar apoptotic changes such as increased Annexin V-FITC positive cells, increased cytochrome c release and increased activation of caspase-9 and caspase-3 (P < 0.05). GTT treatment resulted in a significant reduction of Annexin V-FITC positive cells, inhibited cytochrome c release and decreased activation of caspase-9 and caspase-3 (P < 0.05). Gene expression analysis showed that GTT treatment down regulated BAX mRNA, up-regulated BCL2A1 mRNA and decreased the ratio of Bax/Bcl-2 protein expression (P < 0.05) in SIPS. These findings suggested that GTT inhibits apoptosis by modulating the upstream apoptosis cascade, causing the inhibition of cytochrome c release from the mitochondria with concomitant suppression of caspase-9 and caspase-3 activation. In conclusion, GTT delays cellular senescence of human diploid fibroblasts through the inhibition of intrinsic mitochondria-mediated pathway which involved the regulation of pro- and anti-apoptotic genes and proteins.
  7. Hussein SZ, Mohd Yusoff K, Makpol S, Mohd Yusof YA
    PMID: 22919407 DOI: 10.1155/2012/109636
    Natural honey is well known for its therapeutic value and has been used in traditional medicine of different cultures throughout the world. The aim of this study was to investigate the anti-inflammatory effect of Malaysian Gelam honey in inflammation-induced rats. Paw edema was induced by a subplantar injection of 1% carrageenan into the rat right hind paw. Rats were treated with the nonsteroidal anti-inflammatory drug (NSAID) Indomethacin (10 mg/kg, p.o.) or Gelam honey at different doses (1 or 2 g/kg, p.o.). The increase in footpad thickness was considered to be edema, which was measured using a dial caliper. Plasma and paw tissue were collected to analyze the production of inflammatory mediators, such as NO, PGE(2), TNF-α, and IL-6, as well as iNOS and COX-2. The results showed that Gelam honey could reduce edema in a dose-dependent fashion in inflamed rat paws, decrease the production of NO, PGE(2), TNF-α, and IL-6 in plasma, and suppress the expression of iNOS, COX-2, TNF-α, and IL-6 in paw tissue. Oral pretreatment of Gelam honey at 2 g/kg of body weight at two time points (1 and 7 days) showed a significantly decreased production of proinflammatory cytokines, which was similar to the effect of the anti-inflammatory drug Indomethacin (NSAID), both in plasma and tissue. Thus, our results suggest that Gelam honey has anti-inflammatory effects by reducing the rat paw edema size and inhibiting the production of proinflammatory mediators. Gelam honey is potentially useful for treating inflammatory conditions.
  8. Zaman WS, Makpol S, Sathapan S, Chua KH
    J Tissue Eng Regen Med, 2014 Jan;8(1):67-76.
    PMID: 22552847 DOI: 10.1002/term.1501
    In the field of cell-based therapy and regenerative medicine, clinical application is the ultimate goal. However, one major concern is: does in vitro manipulation during culture expansion increases tumourigenicity risk on the prepared cells? Therefore, the aim of this study was to investigate the effect of long-term in vitro expansion on human adipose-derived stem cells (ASCs). The ASCs were harvested from lipo-aspirate samples and cultured until passage 20 (P20), using standard culture procedures. ASCs at P5, P10, P15 and P20 were analysed for morphological changes, DNA damage (Comet assay), tumour suppressor gene expression level (quantitative PCR), p53 mutation, telomerase activity, telomere length determination and in vivo tumourigenicity test. Our data showed that ASCs lost their fibroblastic feature in long-term culture. The population doubling time of ASCs increased with long-term culture especially at P15 and P20. There was an increase in DNA damage at later passages (P15 and P20). No significant changes were observed in both p53 and p21 genes expression throughout the long-term culture. There was also no p53 mutation detected and no significant changes were recorded in the relative telomerase activity (RTA) and mean telomere length (TRF) in ASCs at all passages. In vivo implantation of ASCs at P15 and P20 into the nude mice did not result in tumour formation after 4 months. The data showed that ASCs have low risk of tumourigenicity up to P20, with a total population doubling of 42 times. This indicates that adipose tissue should be a safe source of stem cells for cell-based therapy.
  9. Safwani WK, Makpol S, Sathapan S, Chua KH
    Cell Tissue Bank, 2013 Jun;14(2):289-301.
    PMID: 22476937 DOI: 10.1007/s10561-012-9309-1
    Adipose tissue is a source of multipotent stem cells and it has the ability to differentiate into several types of cell lineages such as neuron cells, osteogenic and adipogenic cells. Most studies on human adipose-derived stem cells (ASCs) have been carried out at the early passages. For clinical usage, ASCs need to be expanded in vitro for a period of time to get sufficient cells for transplantation into patients. However, the impact of long-term culture on ASCs molecular characteristics has not been established yet. Several studies have also shown that osteogenic and adipogenic cells have the ability to switch pathways during in vitro culture as they share the same progenitor cells. This data is important to ensure their functionality and efficacy before being used clinically in the treatment of bone diseases. Therefore, we aim to investigate the effect of long-term culture on the adipogenic, stemness and osteogenic genes expression during osteogenic induction of ASCs. In this study, the molecular characteristics of ASCs during osteogenic induction in long-term culture was analysed by observing their morphological changes during induction, analysis of cell mineralization using Alizarin Red staining and gene expression changes using quantitative RT-PCR. Morphologically, cell mineralization at P20 was less compared to P5, P10 and P15. Adipogenesis was not observed as negative lipid droplets formation was recorded during induction. The quantitative PCR data showed that adipogenic genes expression e.g. LPL and AP2 decreased but PPAR-γ was increased after osteogenic induction in long-term culture. Most stemness genes decreased at P5 and P10 but showed no significant changes at P15 and P20. While most osteogenic genes increased after osteogenic induction at all passages. When compared among passages after induction, Runx showed a significant increased at P20 while BSP, OSP and ALP decreased at later passage (P15 and P20). During long-term culture, ASCs were only able to differentiate into immature osteogenic cells.
  10. Abukhadir SS, Mohamed N, Makpol S, Muhammad N
    PMID: 23049610 DOI: 10.1155/2012/656025
    The study determines the effects of palm vitamin E on the gene expression of bone-formation-related genes in nicotine-treated rats. Male rats were divided into three groups: normal saline olive oil (NSO), nicotine olive oil (NO), and nicotine palm vitamin E (NE). The treatment was carried out in 2 phases. During the first 2 months, the NSO group received normal saline while the NO and NE groups received nicotine 7 mg/kg, 6 days a week, intraperitoneally. The following 2 months, normal saline and nicotine administration was stopped and was replaced with oral supplementation of olive oil for the NSO and NO groups and oral supplementation of palm vitamin E (60 mg/kg) for the NE group. Both femurs were harvested to determine the gene expression of bone morphogenetic protein-2 (BMP-2), Osterix (OSX), and Runt-related transcription factor 2 (RUNX2). Nicotine significantly downregulated the gene expression. This effect was reversed by palm vitamin E treatment. In conclusion, palm vitamin E may play a role in osteoblast differentiation and can be considered as an anabolic agent to treat nicotine-induced osteoporosis.
  11. Wan Safwani WK, Makpol S, Sathapan S, Chua KH
    Biotechnol. Appl. Biochem., 2011 Jul-Aug;58(4):261-70.
    PMID: 21838801 DOI: 10.1002/bab.38
    One of the advantages of human adipose-derived stem cells (ASCs) in regenerative medicine is that they can be harvested in abundance. However, the stemness biomarkers, which marked the safety and efficacy of ASCs in accordance with the good manufacturing practice guidelines, is not yet well established. This study was designed to investigate the effect of long-term culture on the stemness properties of ASCs using quantitative real-time polymerase chain reaction and flow cytometry. Results showed the growth rate of ASCs was at its peak when they reached P10 (population doubling; PD = 26) but started to decrease when they were expanded to P15 (PD = 36) and P20 (PD = 46). The ASCs can be culture expanded with minimal alteration in the stemness genes and cluster of differentiation (CD) markers expression up to P10. Expression level of Sox2, Nestin, and Nanog3 was significantly decreased at later passage. CD31, CD45, CD117, and human leukocyte antigen DR, DQ, and DP were lowly expressed at P5 and P10 but their expressions increased significantly at P15 or P20. The differentiation ability of ASCs (adipogenesis, osteogenesis, and neurogenesis) also decreased in long-term culture. Our findings suggested that P10 (PD = 26) should be the "cutoff point" for clinical usage because ASCs at passage 15 onward showed significant changes in the stemness genes, CD markers expression, and differentiation capability.
  12. Safwani WK, Makpol S, Sathapan S, Chua KH
    Appl. Biochem. Biotechnol., 2012 Apr;166(8):2101-13.
    PMID: 22391697 DOI: 10.1007/s12010-012-9637-4
    Human adipose-derived stem cells (ASCs) have generated a great deal of excitement in regenerative medicine. However, their safety and efficacy issue remain a major concern especially after long-term in vitro expansion. The aim of this study was to investigate the fundamental changes of ASCs in long-term culture by studying the morphological feature, growth kinetic, surface marker expressions, expression level of the senescence-associated genes, cell cycle distribution and ß-galactosidase activity. Human ASCs were harvested from lipoaspirate obtained from 6 patients. All the parameters mentioned above were measured at P5, P10, P15 and P20. Data were subjected to one-way analysis of variance with a Tukey post hoc test to determine significance difference (P < 0.05). The data showed that growth of ASCs reduced in long-term culture and the ß-galactosidase activity was significantly increased at later passage (P20). The morphology of ASCs in long-term culture showed the manifestation of senescent feature at P15 and P20. Significant alteration in the senescence-associated genes expression levels was observed in MMP1, p21, Rb and Cyclin D1 at P15 and P20. Significant increase in CD45 and HLA DR DQ DP surface marker was observed at P20. While cell cycle analysis showed significant decrease in percentage of ASCs at S and G2/M phase at later passage (P15). Our data showed ASCs cultured beyond P10 favours the senescence pathway and its clinical usage in cell-based therapy may be limited.
  13. Wan Safwani WK, Makpol S, Sathapan S, Chua KH
    PMID: 22221649 DOI: 10.1186/1477-5751-11-3
    Adipose tissue is a source of multipotent adult stem cells and it has the ability to differentiate into several types of cell lineages such as neuron cells, osteogenic cells and adipogenic cells. Several reports have shown adipose-derived stem cells (ASCs) have the ability to undergo cardiomyogenesis. Studies have shown 5-azacytidine can successfully drive stem cells such as bone marrow derived stem cells to differentiate into cardiomyogenic cells. Therefore, in this study, we investigated the effect 5-azacytidine on the cardiogenic ability of ASCs.
  14. Hussein SZ, Yusoff KM, Makpol S, Yusof YA
    Molecules, 2011 Jul 27;16(8):6378-95.
    PMID: 21796076 DOI: 10.3390/molecules16066378
    Two types of monofloral Malaysian honey (Gelam and Nenas) were analyzed to determine their antioxidant activities and total phenolic and flavonoid contents, with and without gamma irradiation. Our results showed that both types of honey can scavenge free radicals and exhibit high antioxidant-reducing power; however, Gelam honey exhibited higher antioxidant activity (p < 0.05) than Nenas honey, which is in good correlation (r = 0.9899) with its phenolic contents. Interestingly, we also noted that both irradiated honeys have higher antioxidant activities and total phenolic and flavonoid contents compared to nonirradiated honeys by Folin-Ciocalteu and UV-spectrophotometry methods, respectively. However, HPLC analysis for phenolic compounds showed insignificant increase between irradiated and nonirradiated honeys. The phenolic compounds such as: caffeic acid, chlorogenic acid, ellagic acid, p- coumaric acid, quercetin and hesperetin as indicated by HPLC method were found to be higher in Gelam honey versus Nenas honey. In conclusion, irradiation of honey causes enhanced antioxidant activities and flavonoid compounds.
  15. Zainuddin A, Chua KH, Abdul Rahim N, Makpol S
    BMC Mol. Biol., 2010;11:59.
    PMID: 20707929 DOI: 10.1186/1471-2199-11-59
    Several genes have been used as housekeeping genes and choosing an appropriate reference gene is important for accurate quantitative RNA expression in real time RT-PCR technique. The expression levels of reference genes should remain constant between the cells of different tissues and under different experimental conditions. The purpose of this study was to determine the effect of different experimental treatments on the expression of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA so that the reliability of GAPDH as reference gene for quantitative real time RT-PCR in human diploid fibroblasts (HDFs) can be validated. HDFs in 4 different treatment groups viz; young (passage 4), senescent (passage 30), H2O2-induced oxidative stress and gamma-tocotrienol (GTT)-treated groups were harvested for total RNA extraction. Total RNA concentration and purity were determined prior to GAPDH mRNA quantification. Standard curve of GAPDH expression in serial diluted total RNA, melting curve analysis and agarose gel electrophoresis were used to determine the reliability of GAPDH as reference gene.
  16. Zaman WS, Makpol S, Santhapan S, Chua KH
    Med. J. Malaysia, 2008 Jul;63 Suppl A:61-2.
    PMID: 19024984
    It is crucial to know whether stem cells retain its stemnness properties after advance in vitro manipulation. The objective of this study was to investigate the stemness gene expression of human adipose tissue derived stem cells (ADSCs) in long-term culture using quantitative RT-PCR technique. Our data showed that the expression level of Sox-2, Rex-1, FGF-4, Nanog, Nestin, BST-1, FZD-9 and Oct-4 were decreased gradually in long-term culture. This could mean that the ability of ADSCs to differentiate into other cell lineages reduce after extensive culture.
  17. Hussein SZ, Mohd Yusoff K, Makpol S, Mohd Yusof YA
    PLoS ONE, 2013;8(8):e72365.
    PMID: 24015236 DOI: 10.1371/journal.pone.0072365
    The activation of nuclear factor kappa B (NF-κB) plays a major role in the pathogenesis of a number of inflammatory diseases. In this study, we investigated the anti-inflammatory mechanism of Gelam honey in inflammation induced rats via NF-κB signalling pathway. Rats paw edema was induced by subplantar injection of 1% carrageenan into the right hind paw. Rats were pre-treated with Gelam honey at different doses (1 or 2 g/kg, p.o.) and NSAID Indomethacin (10 mg/kg, p.o.), in two time points (1 and 7 days). Our results showed that Gelam honey at both concentrations suppressed the gene expressions of NF-κB (p65 & p50) and IκBα in inflamed rats paw tissues. In addition, Gelam honey inhibited the nuclear translocation and activation of NF-κB and decreased the cytosolic degradation of IκBα dose dependently in inflamed rats paw tissues. The immunohistochemical expressions of pro-inflammatory mediators COX-2 and TNF-α were also decreased in inflamed rats paw tissues when treated with Gelam honey. The results of our findings suggest that Gelam honey exhibits its inhibitory effects by attenuating NF-κB translocation to the nucleus and inhibiting IκBα degradation, with subsequent decrease of inflammatory mediators COX-2 and TNF-α.
  18. Khor SC, Mohd Yusof YA, Wan Ngah WZ, Makpol S
    Clin Ter, 2015;166(2):e81-90.
    PMID: 25945449 DOI: 10.7417/CT.2015.1825
    BACKGROUND AND OBJECTIVE: Vitamin E has been suggested as nutritional intervention for the prevention of degenerative and age-related diseases. In this study, we aimed to elucidate the underlying mechanism of tocotrienol-rich fraction (TRF) in delaying cellular aging by targeting the proliferation signaling pathways in human diploid fibroblasts (HDFs).

    MATERIALS AND METHODS: Tocotrienol-rich fraction was used to treat different stages of cellular aging of primary human diploid fibroblasts viz. young (passage 6), pre-senescent (passage 15) and senescent (passage 30). Several selected targets involved in the downstream of PI3K/AKT and RAF/MEK/ERK pathways were compared in total RNA and protein.

    RESULTS: Different transcriptional profiles were observed in young, pre-senescent and senescent HDFs, in which cellular aging increased AKT, FOXO3, CDKN1A and RSK1 mRNA expression level, but decreased ELK1, FOS and SIRT1 mRNA expression level. With tocotrienol-rich fraction treatment, gene expression of AKT, FOXO3, ERK and RSK1 mRNA was decreased in senescent cells, but not in young cells. The three down-regulated mRNA in cellular aging, ELK1, FOS and SIRT1, were increased with tocotrienol-rich fraction treatment. Expression of FOXO3 and P21Cip1 proteins showed up-regulation in senescent cells but tocotrienol-rich fraction only decreased P21Cip1 protein expression in senescent cells.

    CONCLUSIONS: Tocotrienol-rich fraction exerts gene modulating properties that might be responsible in promoting cell cycle progression during cellular aging.

  19. Khee SG, Yusof YA, Makpol S
    Oxid Med Cell Longev, 2014;2014:725929.
    PMID: 25132913 DOI: 10.1155/2014/725929
    Emerging evidences highlight the implication of microRNAs as a posttranscriptional regulator in aging. Several senescence-associated microRNAs (SA-miRNAs) are found to be differentially expressed during cellular senescence. However, the role of dietary compounds on SA-miRNAs remains elusive. This study aimed to elucidate the modulatory role of tocotrienol-rich fraction (TRF) on SA-miRNAs (miR-20a, miR-24, miR-34a, miR-106a, and miR-449a) and established target genes of miR-34a (CCND1, CDK4, and SIRT1) during replicative senescence of human diploid fibroblasts (HDFs). Primary cultures of HDFs at young and senescent were incubated with TRF at 0.5 mg/mL. Taqman microRNA assay showed significant upregulation of miR-24 and miR-34a and downregulation of miR-20a and miR-449a in senescent HDFs (P < 0.05). TRF reduced miR-34a expression in senescent HDFs and increased miR-20a expression in young HDFs and increased miR-449a expression in both young and senescent HDFs. Our results also demonstrated that ectopic expression of miR-34a reduced the expression of CDK4 significantly (P < 0.05). TRF inhibited miR-34a expression thus relieved its inhibition on CDK4 gene expression. No significant change was observed on the expression of CCND1, SIRT1, and miR-34a upstream transcriptional regulator, TP53. In conclusion tocotrienol-rich fraction prevented cellular senescence of human diploid fibroblasts via modulation of SA-miRNAs and target genes expression.
  20. Safwani WK, Makpol S, Sathapan S, Chua K
    Arch Med Sci, 2014 Jun 29;10(3):597-606.
    PMID: 25097593 DOI: 10.5114/aoms.2014.43753
    Adipose tissue is a source of multipotent adult stem cells. Most studies on human adipose-derived stem cells (ASC) have been on the early passages. Studies in extensive expansion have not been well established yet. In this study, we aim to investigate the effects of extensive expansion on the adipogenic differentiation capability of ASC.
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