The antimalarial effect of curcumin is mediated by the inhibition of glycogen synthase kinase-3β

Curcumin, a bioactive compound in Curcuma longa, exhibits various pharmacological activities, including antimalarial effects. In silico docking simulation studies suggest that curcumin possesses glycogen synthase kinase-3β (GSK3β)-inhibitory properties. The involvement of GSK3 in the antimalarial effects in vivo is yet to be demonstrated. In this study, we aimed to evaluate whether the antimalarial effects of curcumin involve phosphorylation of host GSK3β. Intraperitoneal administration of curcumin into Plasmodium berghei NK65-infected mice resulted in dose-dependent chemosuppression of parasitemia development. At the highest dose tested (30 mg/kg body weight), both therapeutic and prophylactic administrations of curcumin resulted in suppression exceeding 50% and improved median survival time of infected mice compared to control. Western analysis revealed a 5.5-fold (therapeutic group) and 1.8-fold (prophylactic group) increase in phosphorylation of Ser 9 GSK3β and 1.6-fold (therapeutic group) and 1.7-fold (prophylactic group) increase in Ser 473 Akt in liver of curcumin-treated infected animals. Following P. berghei infection, levels of pro- and anti-inflammatory cytokines, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-10, and IL-4 were elevated by 7.5-, 35.0-, 33.0-, and 2.2-fold, respectively. Curcumin treatment (therapeutic) caused a significant decrease (by 6.0- and 2.0-fold, respectively) in serum TNF-α and IFN-γ level, while IL-10 and IL-4 were elevated (by 1.4- and 1.8-fold). Findings from the present study demonstrate for the first time that the antimalarial action of curcumin involved inhibition of GSK3β

Pencirian molekul glikogen sintase kinase-3 dari Eimeria tenella

Penemuan sasaran dadah antikoksidia baharu merupakan antara usaha yang diperlukan untuk mengawal penyakit koksidiosis ayam yang disebabkan oleh spesies Eimeria. Dalam kajian ini, serpihan yang mengekodkan glikogen sintase kinase-3 (GSK-3) Eimeria tenella putatif telah diamplifikasi daripada cDNA E. tenella. Hasil pemadanan homologi menunjukkan jujukan GSK-3 E. tenella yang terjana mempunyai padanan yang tinggi dengan jujukan GSK-3 organisma lain. Domain terpulihara GSK-3 dan residu yang penting untuk aktiviti GSK-3 juga diramalkan hadir dalam jujukan GSK-3 E. tenella. Analisis struktur sekunder serta pemodelan homologi menunjukkan pembahagian struktur protein kepada domain bebenang beta pada hujung N dan domain heliks alfa pada hujung C, yang merupakan ciri enzim GSK-3. Kesemua hasil analisis ini menyokong bahawa jujukan yang dikaji mengekodkan protein GSK-3 dalam E. tenella. Walaupun darjah keterpuliharaan adalah tinggi, namun terdapat perbezaan yang bermakna diperhatikan antara GSK-3 E. tenella dan perumahnya. Residu Ser 9 yang dilaporkan penting untuk perencatan aktiviti GSK-3 didapati tidak terpulihara dalam GSK-3 E. tenella. Memandangkan Ser 9 merupakan tapak pemfosfatan bagi GSK-3β dalam haiwan vertebrata, ketiadaan residu ini dalam jujukan GSK-3 E. tenella mencadangkan bahawa pengawalaturan GSK-3 E. tenella melibatkan tapak pemfosfatan dan mekanisme yang berbeza. Tambahan pula, hasil analisis filogenetik menunjukkan bahawa GSK-3 E. tenella mempunyai pertalian yang rapat dengan protein GSK-3 tumbuh-tumbuhan. Analisis superposisi GSK-3 E. tenella dengan GSK-3β Homo sapiens pula menunjukkan bahawa perencat GSK-3 mampu berinteraksi dengan protein GSK-3 E. tenella. Keputusan kajian ini mencadangkan bahawa GSK-3 E. tenella mempunyai potensi untuk diperkembangkan sebagai sasaran dadah antikoksidia

Anti-malarial and anti-inflammatory effects of Gleichenia truncata mediated through inhibition of GSK3ß

Gleichenia truncata is a highland fern from the Gleicheniaceae family known for its traditional use among indigenous communities in Asia to treat fever. The scientific basis of its effect has yet to be documented. A yeast-based kinase assay conducted in our laboratory revealed that crude methanolic extract (CME) of G. truncata exhibited glycogen synthase kinase-3 (GSK3)-inhibitory activity. GSK3β is now recognized to have a pivotal role in the regulation of inflammatory response during bacterial infections. We have also previously shown that lithium chloride (LiCl), a GSK3 inhibitor suppressed development of Plasmodium berghei in a murine model of malarial infection. The present study is aimed at evaluating G. truncata for its anti-malarial and anti-inflammatory effects using in vivo malarial and melioidosis infection models respectively. In a four-day suppressive test, intraperitoneal injections of up to 250 mg/kg body weight (bw) G. truncata CME into P.berghei-infected mice suppressed parasitaemia development by >60%. Intraperitoneal administration of 150 mg/kg bw G. truncata CME into Burkholderia pseudomallei-infected mice improved survivability by 44%. G. truncata CME lowered levels of pro-inflammatory cytokines (TNF-α, IFN-γ) in serum and organs of B. pseudomallei-infected mice. In both infections, increased phosphorylations (Ser9) of GSK3β were detected in organ samples of animals administered with G. truncata CME compared to controls. Taken together, results from this study strongly suggest that the anti-malarial and anti-inflammatory effects elicited by G. truncata in part were mediated through inhibition of GSK3β. The findings provide scientific basis for the ethnomedicinal use of this fern to treat inflammation-associated symptoms

Anti-malarial and anti-inflammatory effects of Gynura procumbens are mediated by kaempferol via inhibition of glycogen synthase kinase-3ß (GSK3ß)

Gynura procumbens is a medicinal plant, traditionally used to treat inflammation and fever. A yeast-based assay detected GSK3â-inhibitory activity in the aqueous extract of G. procumbens. GSK3â is now known to have a central role in the modulation of host inflammatory response during bacterial infections. In this study, we investigated the involvement of GSK3â in the anti-malarial and anti-inflammatory effects of an aqueous extract of G. procumbens. Our results showed that G. procumbens inhibited growth of P. falciparum 3D7. Consecutive four-day administration of 250 mg/kg body weight (b.w.) G. procumbens resulted in strong chemosuppression and improved survivability in P. berghei-infected mice. B. pseudomallei-infected mice treated with G. procumbens (50 mg/kg b.w.) showed increased survivability. TNF-á and IFN-ã levels in liver and serum of B. pseudomallei-infected mice were lowered by G. procumbens treatment. IL-10 level was higher in serum of G. procumbens-administered infected mice. G. procumbens treatment of P. berghei-and B. pseudomallei-infected animals each resulted in increased hepatic GSK3â (Ser9) phosphorylation. It is noteworthy that kaempferol (one of the compounds in G. procumbens) also inhibited the growth of P. falciparum 3D7; showed strong chemosuppression and improved survivability in P. berghei-infected mice at 5 mg/kg b.w. B. pseudomallei-infected mice treated with kaempferol (10 mg/kg b.w.) showed improved survivability. Concomitantly, the described effects due to kaempferol also involved enhanced GSK3â (Ser9) phosphorylation as observed with G. procumbens. In summary, the observed anti-malarial and anti-inflammatory effects of G. procumbens involved inhibition of GSK3â and kaempferol may in part be responsible for the pharmacological effects

Economic Growth and Internet Usage Impact on Publication Productivity among ASEAN’s and World’s Best Universities

Measuring the number of papers which are published each year, publication productivity is the factor which shows the reputation of universities and countries. However, the effect of growing economy and using internet on the publication productivity in Asian countries has not been discovered yet. The present research is going to figure out the publication productivity among the elite universities in Asian countries and also ten top universities around the world in the last twenty years (from 1993 to 2012). Furthermore, the current research is aimed to study the relationship among publication, gross domestic product (GDP) and internet usage. It is worth to mention that the publication of the top Ten Malaysian Universities was regarded for the similar period of time. To get the exact numbers of documents like papers, conference articles, review papers and letters which are published by the universities in the last twenty years, the writer of the same paper used the Science Direct database. Moreover, the data for GDP and the number of internet usage was collected through the World Bank database (World Data Bank).To compare all kinds of publications,one-way ANOVA was used and to investigate the impact of economic growth and internet usage on publication productivity, multiple regression analysis was applied.The results showed that the rate of publication growth was 1.9, 20.9, and 65.5 in top universities in the world, ASEAN countries and Malaysia, respectively.The results also showed that there was a positive and significant correlation between GDP and the number of internet users with the number of publications in ASEAN and Malaysian universities. Internet usage had much more influence in comparison with the GDP in predicting the number of publications among these groups except for top ten Malaysian universities from 2003 to 2012. In summary, publication trends in top ten Malaysian and ASEAN universities are promising. However, policy makers and science managers should spend much more percentage of their GDP on Internet facilities and research studies that their outputs lead to more rapid economic growth and internet usage

A predicted structure of the cytochrome c oxidase from Burkholderia pseudomallei

Cytochrome c oxidase, the terminal enzyme of the respiratory chains of mitochondria and aerobic bacteria, catalyzes electron transfer from cytochrome c to molecular oxygen. The enzyme belongs to the haem-copper-containing oxidases superfamily. A recombinant plasmid carrying a 2.0 kb insert from a Burkholderia pseudomallei genomic library was subjected to automated DNA sequencing utilizing a primer walking strategy. Analysis of the 2002 bp insert revealed a 1536 bp open reading frame predicted to encode a putative cytochrome c oxidase. Further analysis using sequence alignments and tertiary structure analysis tools demonstrated that the hypothetical B. pseudomallei cytochrome c oxidase is similar to cytochrome c oxidases from other organisms such as Thermus thermophilus (36% protein sequence identity), Paracoccus denitrificans and bovine heart mitochondrial, the latter two which crystal structures available. The deduced 512 residue protein sequence includes the six canonical histidine residues involved in binding the low spin heme B and the binuclear center CuB/hemeA. The predicted tertiary structure of the hypothetical protein is consistent with previous models of electron transfer for cytochrome c oxidase

Assessment of the inhibitory mechanism of action for a yeast cell-based screening system targeting glycogen synthase kinase-3ß (GSK-3ß)

Background and Objective: Glycogen Synthase Kinase-3 (GSK-3) is one of the prior targets for drug discovery due to its involvement in many cell signaling and metabolism. It has been implicated in several critical diseases such as diabetes, Alzheimer’s disease, cancer and inflammation. To date, many GSK-3 inhibitors have been identified and classified into different type such as inorganic atom, ATP competitive and non-ATP competitive types. Many laboratories worldwide are still actively screening for bioactive compounds for GSK-3 inhibitory activity using diverse screening systems. This study assessed an assay developed using a yeast cell-based system specifically targeting GSK-3β for preliminary screening and cost effectiveness. Methodology: In this study, the GSK-3 homologues in yeast (MCK1, MDS1, MRK1 and YOL128C) were knocked out and inserted with mammalian GSK-3β. In order to determine the inhibitory mechanism, known GSK-3β inhibitors were tested and evaluated. Results: The GSK-3β inhibitor I and staurosporine showed inhibition on GSK-3β activity at a concentration of 1 and 20 μg disc–1, respectively. Other known inhibitors, such as indirubin-3’-monoxime, kenpaullone, GSK-3 inhibitor IV and enzastaurin showed no detectable inhibition in this study. Conclusion: The GSK-3β inhibitor I and staurosporine interacted with the same amino acid on GSK-3β which is Cys199 while other inhibitors have no interactions with Cys199 as reported in docking study. This study suggests that this yeast cell-based system can be used to screen GSK-3β inhibitors that is targeting on Cys199 residue

Anti-malarial activities of two actinomycete isolates from sabah soil involved inhibition of glycogen synthase kinase 3ß

Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition, our study suggests that DBP is in part the bioactive component contributing to the antimalarial activity displayed by H11809 acting through the inhibition of GSK3β