Mohammad Tariqur Rahman
University of Malaya
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Publication
Featured researches published by Mohammad Tariqur Rahman.
The Scientific World Journal | 2013
Nazmul Haque; Mohammad Tariqur Rahman; Noor Hayaty Abu Kasim; Aied M. Alabsi
Cell-based regenerative therapies, based on in vitro propagation of stem cells, offer tremendous hope to many individuals suffering from degenerative diseases that were previously deemed untreatable. Due to the self-renewal capacity, multilineage potential, and immunosuppressive property, mesenchymal stem cells (MSCs) are considered as an attractive source of stem cells for regenerative therapies. However, poor growth kinetics, early senescence, and genetic instability during in vitro expansion and poor engraftment after transplantation are considered to be among the major disadvantages of MSC-based regenerative therapies. A number of complex inter- and intracellular interactive signaling systems control growth, multiplication, and differentiation of MSCs in their niche. Common laboratory conditions for stem cell culture involve ambient O2 concentration (20%) in contrast to their niche where they usually reside in 2–9% O2. Notably, O2 plays an important role in maintaining stem cell fate in terms of proliferation and differentiation, by regulating hypoxia-inducible factor-1 (HIF-1) mediated expression of different genes. This paper aims to describe and compare the role of normoxia (20% O2) and hypoxia (2–9% O2) on the biology of MSCs. Finally it is concluded that a hypoxic environment can greatly improve growth kinetics, genetic stability, and expression of chemokine receptors during in vitro expansion and eventually can increase efficiency of MSC-based regenerative therapies.
Food and Chemical Toxicology | 2008
Nor Suhada Anuar; Shafiyyah Solehah Zahari; Ibrahim Adham Taib; Mohammad Tariqur Rahman
The traditional use of papaya to treat many diseases, especially skin conditions and its prohibition for consumption during pregnancy has prompted us to determine whether papaya extracts both from green and ripe fruits improve wound healing and also produce foetal toxicity. Aqueous extracts of green papaya epicarp (GPE) and ripe papaya epicarp (RPE) were applied on induced wounds on mice. GPE treatment induced complete healing in shorter periods (13 days) than that required while using RPE (17 days), sterile water (18 days) and Solcoseryl ointment (21 days). Extracts were administered orally (1 mg/g body weight/day) to pregnant mice from day 10 and onwards after conception. 3 (n=7) mice and 1 (n=6) mice given RPE and misoprostol, an abortive drug, respectively experienced embryonic resorption while this effect was observed in none of the mice given GPE (n=5) and water (n=5). The average body weight of live pups delivered by mice given GPE (1.12+/-0.04 g) was significantly lower than those delivered by mice given water (1.38+/-0.02 g). In SDS-PAGE, proteins were distributed in three bands (Mr range approximately 8-29 kDa). Band intensity at Mr approximately 28-29 kDa was higher in GPE than in RPE. In contrast, band intensity at low Mr (approximately 8 kDa) was found to be higher in RPE than in GPE. Notably, the band corresponding to Mr approximately 23-25 kDa was absent in RPE. These differences in composition may have contributed to the different wound healing and abortive effects of green and ripe papaya.
International Journal of Biological Sciences | 2015
Nazmul Haque; Noor Hayaty Abu Kasim; Mohammad Tariqur Rahman
Mesenchymal stem cells (MSCs) are considered a potential tool for cell based regenerative therapy due to their immunomodulatory property, differentiation potentials, trophic activity as well as large donor pool. Poor engraftment and short term survival of transplanted MSCs are recognized as major limitations which were linked to early cellular ageing, loss of chemokine markers during ex vivo expansion, and hyper-immunogenicity to xeno-contaminated MSCs. These problems can be minimized by ex vivo expansion of MSCs in hypoxic culture condition using well defined or xeno-free media i.e., media supplemented with growth factors, human serum or platelet lysate. In addition to ex vivo expansion in hypoxic culture condition using well defined media, this review article describes the potentials of transient adaptation of expanded MSCs in autologous serum supplemented medium prior to transplantation for long term regenerative benefits. Such transient adaptation in autologous serum supplemented medium may help to increase chemokine receptor expression and tissue specific differentiation of ex vivo expanded MSCs, thus would provide long term regenerative benefits.
Biological Trace Element Research | 2018
Mohammad Tariqur Rahman; Muhammad Manjurul Karim
Nutritional immunity describes mechanisms for withholding essential transition metals as well as directing the toxicity of these metals against infectious agents. Zinc is one of these transition elements that are essential for both humans and microbial pathogens. At the same time, Zn can be toxic both for man and microbes if its concentration is higher than the tolerance limit. Therefore a “delicate” balance of Zn must be maintained to keep the immune cells surveilling while making the level of Zn either to starve or to intoxicate the pathogens. On the other hand, the invading pathogens will exploit the host Zn pool for its survival and replication. Apparently, different sets of protein in human and bacteria are involved to maintain their Zn need. Metallothionein (MT)—a group of low molecular weight proteins, is well known for its Zn-binding ability and is expected to play an important role in that Zn balance at the time of active infection. However, the differences in structural, functional, and molecular control of biosynthesis between human and bacterial MT might play an important role to determine the proper use of Zn and the winning side. The current review explains the possible involvement of human and bacterial MT at the time of infection to control and exploit Zn for their need.
Journal of Trace Elements in Medicine and Biology | 2009
Pegah Maghdooni Bagheri; Mohammad Tariqur Rahman; Sofie Van Soest; Marc De Ley
The expression pattern of functional members of the metallothionein (MT) gene family was studied in the haematopoietic precursor cell lines, K562, DAMI, MEG-01, and ELF-153 in order to strengthen the proposed function of MT in differentiation. Cells were cultured in RPMI 1640 with 10% (v/v) foetal calf serum, with or without different zinc supplements. Expression of MT isogenes was analysed by quantitative real-time PCR (RT-PCR) using mRNA extracted from cultured cells. The more mature K562, DAMI, and MEG-01 cell lines exhibited transcription of all MT isogenes, except MT-3 and MT-4. Relative quantitative expression of MT isogenes in the mature cell lines such as K562, DAMI, and MEG-01 was higher than in the immature ELF-153 cell line. Immunohistochemical staining (IHC) reveals an increased MT protein biosynthesis in more mature cell lines such as K562, DAMI and MEG-01 greater than in the immature ELF-153 cell line. Real-time PCR and immunohistochemical staining for investigating the effect of phorbol ester and hemin (haematopoietic differentiation stimuli) on expression of MT isogenes in K562 cells reveals that phorbol ester induces increased MT transcription and biosynthesis. Therefore, to our knowledge, the role of MT in differentiation in human haematopoietic precursor cell lines is here reported for the first time.
Skin Pharmacology and Physiology | 2016
Jazli Aziz; Hafiz Shezali; Zamri Bin Radzi; Noor Azlin Yahya; Noor Hayaty Abu Kassim; Jan T. Czernuszka; Mohammad Tariqur Rahman
Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.
Pharmaceutical Biology | 2015
Abdulrazaq Bidemi Nafiu; Mohammad Tariqur Rahman
Abstract Context: Carica papaya L. (Caricaceae) fruit was shown to exhibit wound healing properties. Objectives: We investigated anti-inflammatory and antioxidant potential of papaya fruit phosphate-buffered saline extract (PE) during wound healing and enhancement of the potentials due to trace ions addition. Materials and methods: Rat excision wounds were topically treated twice/day with 20 µL of PE (5 mg extract/mL), 0.5 µg Se2+ added PE (PES), or 100 µM Zn2+ added PE (PEZ). Control groups were treated with deionized water (negative) and deproteinized calf blood extract ointment (Solcoseryl®, positive). Lipid peroxidation (LPX), antioxidant, proinflammatory, and arginine metabolic enzymes were estimated in the wound excised on days 4 and 10 post wounding. Results: PE (5 mg/mL; 9.80 ± 0.33 d) and PES (PE + 0.5 µg Se2+; 8.90 ± 0.23 d) significantly (p < 0.05) reduced the average time for complete wound closure compared with the negative (13.00 ± 0.37 d) and positive (9.80 ± 0.33 d) controls, respectively. Biochemical evaluations of LPX product (malondialdehyde), antioxidant (catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx)), and pro-inflammatory (cyclooxygenase-2 and myeloperoxidase (MPO)) enzyme activities and metabolites (nitrite and urea), on days 4 and 10 post wounding, confirmed the anti-inflammatory and antioxidant properties of PE and PES in this study. Discussion and conclusion: Treatment of excision wounds with papaya extract, especially with the addition of selenium for 10 d, reduced inflammation associated oxidative damage apparently via cyclooxygenase specific inhibition, arginine metabolism, and up-regulation of antioxidant enzymes.
Reviews of Environmental Contamination and Toxicology | 2016
Mohammad Tariqur Rahman; Marc De Ley
Human exposure to arsenic (As) can lead to oxidative stress that can become evident in organs such as the skin, liver, kidneys and lungs. Several intracellular antioxidant defense mechanisms including glutathione (GSH) and metallothionein (MT) have been shown to minimize As cytotoxicity. The current review summarizes the involvement of MT as an intracellular defense mechanism against As cytotoxicity, mostly in blood. Zinc (Zn) and selenium (Se) supplements are also proposed as a possible remediation of As cytotoxicity. In vivo and in vitro studies on As toxicity were reviewed to summarize cytotoxic mechanisms of As. Intracellular antioxidant defense mechanisms of MT are linked in relation to As cytotoxicity. Arsenic uses a different route, compared to major metal MT inducers such as Zn, to enter/exit blood cells. A number of in vivo and in vitro studies showed that upregulated MT biosynthesis in blood components are related to toxic levels of As. Despite the cysteine residues in MT that aid to bind As, MT is not the preferred binding protein for As. Nonetheless, intracellular oxidative stress due to As toxicity can be minimized, if not eliminated, by MT. Thus MT induction by essential metals such as Zn and Se supplementation could be beneficial to fight against As toxicity.
BMC Complementary and Alternative Medicine | 2015
Jazli Aziz; Noor Lide Abu Kassim; Noor Hayaty Abu Kasim; Nazmul Haque; Mohammad Tariqur Rahman
BackgroundUse of Carica papaya leaf extracts, reported to improve thrombocyte counts in dengue patients, demands further analysis on the underlying mechanism of its thrombopoietic cytokines inductionMethodsIn vitro cultures of peripheral blood leukocytes (PBL) and stem cells from human exfoliated deciduous teeth (SHED) were treated with unripe papaya pulp juice (UPJ) to evaluate its potential to induce thrombopoietic cytokines (IL-6 and SCF)ResultsIn vitro scratch gap closure was significantly faster (p < .05) in SHED culture treated with UPJ. IL-6 concentration was significantly increased (p < .05) in SHED and PBL culture supernatant when treated with UPJ. SCF synthesis in SHED culture was also significantly increased (p < .05) when treated with UPJConclusionIn vitro upregulated synthesis of IL −6 and SCF both in PBL and SHED reveals the potential mechanism of unripe papaya to induce thrombopoietic cytokines synthesis in cells of hematopoietic and mesenchymal origin.
Archive | 2017
Mohammad Tariqur Rahman; Nazmul Haque; Noor Hayaty Abu Kasim; Marc De Ley
Toxic heavy metals, toxic organic compounds, reactive oxygen species (ROS), infections, and temperature are well-known metallothionein (MT) inducers in human blood. The current review aims to summarize synthesis, function, and fate of human blood MT in response to the known MT inducers. Part of the MTs that are synthesized in different organs such as the liver, kidney, and spleen is transported and stored in different blood cells and in plasma. Cells of the circulatory system also synthesize MT. From the circulation, MT returns to the kidney where the metal-bound MTs are degraded to release the metal ion that in turn induces MT expression therein. The blood MTs play important roles in metal detoxification, transportation, and storage. By neutralizing ROS, MTs protect blood cells from oxidative stress-induced cytotoxicity and genotoxicity. Arguably, MTs are also involved in immune suppression. Given the permeating distribution of blood MT throughout the body as well as its diverse role in the protection against harmful environmental factors and in metal homeostasis, MT could be better recognized as a major public health protein.