The PRMT response to inflammation : substrate methylation and alternative splicing

Protein arginine N-methyltransferases (PRMTs) are a family of enzymes involved in signaling pathways and gene expression by methylating arginine residues of substrate proteins. PRMT2 has been demonstrated to play a role in the NF-κB signaling pathway. Moreover, our lab recently revealed association using proteomic techniques between PRMT2 and splicing factors including Src-associated in mitosis 68 kDa protein (SAM68) that mediates the alternative splicing of BCL-X involved in the NF-κB mediated inflammatory pathway. I wanted to investigate if the PRMT activity plays a role in response to inflammation under the treatment of inflammatory cytokine tumor necrosis factor-α (TNF-α) or pro-inflammatory bacterial lipopolysaccharide (LPS) in A549 cells. My proteomic experiments revealed that TNF-α and LPS cause similar changes to arginine methylation for proteins primarily involved in mRNA processing, RNA splicing, and nuclear transport, indicating that these two inflammatory stimuli share mutual downstream pathways involving methyltransferase activity. Among the proteins that showed hypermethylation upon treatment relative to control in mass spectrometry analysis, GAP SH3 domain-binding protein 2 (G3BP2) showed consistently in all three replicates on average a 1.5-fold increase in methylation at the R468 site in both TNF-α and LPS-treated cells. G3BP2 binds to IκB-α and prevents NF-κB translocation into the nucleus for subsequent signaling. G3BP2 methylation was necessary for signaling to occur in the Wnt/β-catenin signaling pathway. Methylation of G3BP2 might also have similar role in the inflammatory pathway that demands further study. Moreover, consistent with an inflammatory response, proteins particularly involved in innate immunity and viral response increased upon TNF-α treatment that could be related to the observed change in methylation of proteins involved in RNA processing. Our finding that PRMT2 interacts with SAM68, prompted me to investigate the potential role of PRMT2 in BCL-X alternative splicing. I found that reduced expression of PRMT2 by siRNA caused a decrease in the BCL-X(L)/BCL-X(s) ratio, suggesting that PRMT2 may contribute to BCL-X alternative splicing. This effect was replicated in TNF-α or LPS stimulated cells when PRMT2 expression was reduced by shRNA, and reversed when PRMT2 expression was increased. These results indicate that PRMT2 may play a role during inflammation in alternative splicing regulation.Pharmaceutical Sciences, Faculty ofGraduat

Anti-diarrhoeal and CNS Depressant Activity of Methanolic Extract of Saccharum spontaneum Linn.

Preliminary phytochemical screening of the methanolic extract of the whole plant of Saccharum spontaneum Linn. (Family- Gramineae) revealed the presence of alkaloids, flavonoids, reducing sugar, tannins and saponins. The antidiarrhoeal activity of the extract (200 and 400 mg/kg) was assessed on experimental animal and a dose dependent decrease in the total number of faecal dropping was obsereved in castor oil induced diarrhoea in mice. The plant extract was also assessed for effect on the central nervous system (CNS) using a number of neuropharmacological experimental models in mice. The extract produced a dosedependent reduction of the onset and duration of pentobarbitone-induced hypnosis, reduction of locomotor and exploratory activities in the open field and hole cross tests. These results suggest that the extract possesses antidiarrhoeal and CNS depressant activity

Stamford Journal of Pharmaceutical Sciences In-vitro Antioxidant and Cytotoxicity Studies of Annona squamosa Linn.

n-Hexane, chloroform and methanol soluble extracts of the leaves of Annona squamosa were screened for their possible antioxidant activitiy by DPPH free radical scavenging and cytotoxicity by brine shrimp lethality bioassay. In DPPH radical scavenging assay, methanol soluble extract was found to be the most potent with an IC50 value of 103.5 µg/ml. The amount of total phenolics was also found to the highest in the methanol soluble extract (283.16 ± 8.90 mg/g), followed by chloroform soluble extract (216.90 ± 4.48 mg/g). Here BHT and ascorbic acid were used as standards with IC50 values 8.2 µg/ml and 25 µg/ml respectively. In the brine shrimp lethality bioassay, the most significant cytotoxicity was observed with chloroform soluble extract with an LC50 of 4.16 µg/ml where vincristine sulphate was used as standard (LC50 0.29 µg/ml)

Methocel K4M Premium Matrix Tablets

In the present study Ciprofloxacin HCl sustained release matrix tablet was prepared by utilizing different grades of hydroxypropyl methylcellulose (HPMC) polymers such as Methocel K4M CR, Methocel K4M Premium & Methocel K15M CR by direct compression method. Different amount of Methocel K15M CR was used to develop matrix builder in the three proposed formulations (F1-F3) for the study of release rate retardant effect at 5%, 6%, and 7 % of total weight of tablet matrix respectively. The dissolution study of Methocel K15M CR based tablet matrices of those proposed formulations were carried out in the simulated gastric medium (pH 1.3) for 8 hours using USP dissolution apparatus II. Similarly Methocel K4M premium was used to develop matrix builder in another three proposed formulations (F4-F6). It was found that formulations F-4 (15%), F-5 (17%) and F-6 (18.3%) met the desired release rate of Ciprofloxacin HCl for 8hrs period. Th

Stamford Journal of Pharmaceutical Sciences In Vitro Nitric Oxide Scavenging Activity of Ethanol Leaf Extracts of Four Bangladeshi Medicinal Plants

The ethanol leaf extracts of four medicinal plants named Hibiscus mutabilis, Leucas aspera, Ixora coccinea and Polyalthia longifolia were examined for their possible regulatory effect on nitric oxide (NO) levels using sodium nitroprusside as a NO donor in vitro. Most of the extracts tested demonstrated direct scavenging of NO and exhibited significant activity and the potency of scavenging activity was in the following order: Leucas aspera> Ixora coccinea> Hibiscus mutabilis> Polyalthia longifolia. All the evaluated extracts exhibited a dose-dependent NO scavenging activity. The ethanolic leaf extract of Leucas aspera showed the greatest NO scavenging effect of 80.50 % at 320 µg/ml with IC50 value of 94.15 µg/ml as compared to the positive control ascorbic acid where 74.56 % scavenging was observed at similar concentration with IC50 value of 62.48 µg/mL. The maximum NO scavenging of Ixora coccinea, Hibiscus mutabilis and Polyalthia longifolia were 79.65 %, 78.60 % and 70.67 % with IC50 values of 43.72 µg/ml, 147.64 µg/ml and 167.08 µg/ml respectively. The present results suggest that these plants might be potent and novel therapeutic agents for scavenging of NO and the regulation of pathological conditions caused by excessive generation of NO and its oxidation product