PUMA mediates ER stress-induced apoptosis in portal hypertensive gastropathy

Mucosal apoptosis has been demonstrated to be an essential pathological feature in portal hypertensive gastropathy (PHG). p53-upregulated modulator of apoptosis (PUMA) was identified as a BH3-only Bcl-2 family protein that has an essential role in apoptosis induced by a variety of stimuli, including endoplasmic reticulum (ER) stress. However, whether PUMA is involved in mucosal apoptosis in PHG remains unclear, and whether PUMA induces PHG by mediating ER stress remains unknown. The aim of the study is to investigate whether PUMA is involved in PHG by mediating ER stress apoptotic signaling. To identify whether PUMA is involved in PHG by mediating ER stress, gastric mucosal injury and apoptosis were studied in both PHG patients and PHG animal models using PUMA knockout (PUMA-KO) and PUMA wild-type (PUMA-WT) mice. The induction of PUMA expression and ER stress signaling were investigated, and the mechanisms of PUMA-mediated apoptosis were analyzed. GES-1 and SGC7901 cell lines were used to further identify whether PUMA-mediated apoptosis was induced by ER stress in vitro. Epithelial apoptosis and PUMA were markedly induced in the gastric mucosa of PHG patients and mouse PHG models. ER stress had a potent role in the induction of PUMA and apoptosis in PHG models, and the apoptosis was obviously attenuated in PUMA-KO mice. Although the targeted deletion of PUMA did not affect ER stress, mitochondrial apoptotic signaling was downregulated in mice. Meanwhile, PUMA knockdown significantly ameliorated ER stress-induced mitochondria-dependent apoptosis in vitro. These results indicate that PUMA mediates ER stress-induced mucosal epithelial apoptosis through the mitochondrial apoptotic pathway in PHG, and that PUMA is a potentially therapeutic target for PHG.     

PPAR gamma-dependent anti-inflammatory action of rosiglitazone in human monocytes: suppression of TNF alpha secretion is not mediated by PTEN regulation

Thiazolidinediones (TZDs) are insulin-sensitising drugs that are ligands for the nuclear receptor PPAR gamma. They have been shown to inhibit PMA-stimulated secretion of TNFalpha from human monocytes, although only at concentrations well in excess of circulating levels observed during TZD therapy, suggesting a mechanism of action independent of PPAR gamma activation. Here we show that insulin-sensitising concentrations of the TZD rosiglitazone partially inhibit serum- or LPS- (but not PMA-) stimulated TNF alpha secretion from primary human monocytes, with an IC(50) of around 50nM. We also show that the observed effects are independent of PPAR gamma-mediated regulation of the lipid phosphatase PTEN. Reversed stimulus specificity, IC(50) in the insulin-sensitising range, and the fact that partial inhibition of TNF alpha secretion is also observed with a structurally unrelated PPAR gamma agonist, GW7845, demonstrate a mechanism of action distinct from that observed with higher TZD concentrations. These findings thus represent the first report of a PPAR gamma-dependent and therapeutically relevant anti-inflammatory action of TZDs in isolated human monocytes.     

Pepsinogen C: a type 2 cell-specific protease

Pepsinogen C, also known as progastricsin or pepsinogen II, is an aspartic protease expressed primarily in gastric chief cells. Prior microarray studies of an in vitro model of type 2 cell differentiation indicated that pepsinogen C RNA was highly induced, comparable to surfactant protein RNA induction. Using second-trimester human fetal lung, third-trimester postnatal and adult lung, and a model of type 2 cell differentiation, we examined the specificity of pepsinogen C expression in lung. Pepsinogen C RNA and protein were only detected in >22 wk gestation samples of neonatal lung or in adult lung tissue. By immunohistochemistry and in situ hybridization, pepsinogen C expression was restricted to type 2 cells. Pepsinogen C expression was rapidly induced during type 2 cell differentiation and rapidly quenched with dedifferentiation of type 2 cells after withdrawal of hormones. In all samples, pepsinogen C expression occurred concomitantly with or in advance of processing of surfactant protein-B to its mature 8-kDa form. Our results indicate that pepsinogen C is a type 2 cell-specific marker that exhibits tight developmental regulation in vivo during human lung development, as well as during in vitro differentiation and dedifferentiation of type 2 cells.     

Microwave-Assisted Organic Synthesis,structure–activity relationship,kinetics and molecular docking studies of non-cytotoxic benzamide derivatives as selective butyrylcholinesterase inhibitors

A series of benzamide derivatives 1–12 with various functional groups (–H, –Br, –F, –OCH₃, –OC₂H₅, and –NO₂) was synthesized using an economic, and facile Microwave-Assisted Organic Synthesis, and evaluated for acetylcholinesterase (ACHE) and butyrylcholinesterase (BCHE) activity in vitro. Structure–activity relationship showed that the substitution of –Br group influenced the inhibitory activity against BCHE enzyme. Synthesized compounds were found to be selective inhibitors of BCHE. In addition, all compounds 1–12 were found to be non-cytotoxic, as compared to the standard cycloheximide (IC₅₀ = 0.8 ± 0.2 µM). Among them, compound 3 revealed the most potent BCHE inhibitory activity (IC₅₀ = 0.8 ± 0.6 µM) when compared with the standard galantamine hydrobromide (IC₅₀ = 40.83 ± 0.37 µM). Enzyme kinetic studies indicated that compounds 1, 3–4, and 7–8 showed a mixed mode of inhibition against BCHE, while compounds 2, 5–6 and 9 exhibited an uncompetitive pattern of inhibition. Molecular docking studies further highlighted the interaction of these inhibitors with catalytically important amino acid residues, such as Glu197, Hip438, Phe329, and many others.     

Mechanism of inhibition of PP2A activity and abnormal hyperphosphorylation of tau by I2(PP2A)/SET

Protein phosphatase-2A (PP2A) activity, which is compromised in Alzheimer disease brain, is regulated by two endogenous inhibitors, one of them being I(2)(PP2A), a 277 amino acid long protein also known as SET. Here we report that both the amino terminal fragment (I(2NTF); aa 1-175) and the carboxy terminal fragment (I(2CTF); aa 176-277) of I(2)(PP2A) inhibit PP2A by binding to its catalytic subunit PP2Ac and cause hyperphosphorylation of tau. The C-terminal acidic region in I(2CTF) and Val 92 in I(2NTF) are essential for their association with PP2Ac and inhibition of the phosphatase activity.     

The ?4817 G>A (rs2238136) variant of the vitamin D receptor gene: a probable risk factor for colorectal cancer

Vitamin D appears to have anti-tumor activities in the large bowel. Our aim was to investigate whether -4817 G>A (rs2238136) polymorphism located at 5'-untranslated region (5'-UTR) of the human vitamin D receptor (VDR) gene was associated with colorectal cancer (CRC) risk. We conducted a case-control study and VDR genotypes, determined by Bpu10I restriction endonuclease digestion of PCR-amplified DNA, were performed on 327 cases with CRC and 327 controls. The distribution of VDR -4817 G>A genotypes and alleles differed significantly between cases with CRC and controls even after adjustment for confounding factors such as age, BMI, sex, and smoking status. Individuals carrying the "AA" genotype had a 2.09-fold increased risk compared with those with "GG" genotype (P?=?0.016, OR?=?2.09, 95% CI?=?1.15-3.78) and a 1.87-fold increased risk compared with those with "GG and GA" genotypes (P?=?0.033, OR?=?1.87, 95% CI?=?1.05-3.33) for CRC. Furthermore, the VDR "A" allele was significantly overrepresented in cases with CRC than controls (P?=?0.044; OR?=?1.28, 95% CI?=?1.01-1.63). Interestingly, the analysis of the SNP revealed that all these associations were stronger for women subjects than for all subjects combined. These data indicated for the first time a direct association between "AA" genotype of VDR gene -4817 G>A polymorphism and CRC, with a stronger association for female subjects. However, our findings remain to be confirmed in other populations.     

Quality Control of Photosystem II: THYLAKOID UNSTACKING IS NECESSARY TO AVOID FURTHER DAMAGE TO THE D1 PROTEIN AND TO FACILITATE D1 DEGRADATION UNDER LIGHT STRESS IN SPINACH THYLAKOIDS*

Photosystem II is vulnerable to light damage. The reaction center-binding D1 protein is impaired during excessive illumination and is degraded and removed from photosystem II. Using isolated spinach thylakoids, we investigated the relationship between light-induced unstacking of thylakoids and damage to the D1 protein. Under light stress, thylakoids were expected to become unstacked so that the photodamaged photosystem II complexes in the grana and the proteases could move on the thylakoids for repair. Excessive light induced irreversible unstacking of thylakoids. By comparing the effects of light stress on stacked and unstacked thylakoids, photoinhibition of photosystem II was found to be more prominent in stacked thylakoids than in unstacked thylakoids. In accordance with this finding, EPR spin trapping measurements demonstrated higher production of hydroxyl radicals in stacked thylakoids than in unstacked thylakoids. We propose that unstacking of thylakoids has a crucial role in avoiding further damage to the D1 protein and facilitating degradation of the photodamaged D1 protein under light stress.In the chloroplasts of higher plants and green algae, thylakoid membranes are closely associated and stack to form grana. Under electron microscopy, cylindrical grana consisting of 10–20 layers of thylakoids have been observed. They have a diameter of 300–600 nm and are interconnected by lamellae of several hundred nm in length (1, 2). The structure of grana in the chloroplasts of higher plants is well known, but the precise role of grana is incompletely understood. Their possible functions in primary photochemical reactions and subsequent events have been discussed extensively (3–9). Photosystem I (PSI)³ and II (PSII) complexes are segregated from each other in thylakoids, showing lateral heterogeneity in their distribution. The PSII complex is a multisubunit pigment-protein complex responsible for the photochemical oxidation of water and reduction of plastoquinone (8, 10–13). It comprises >25 protein subunits and other low molecular weight cofactors, including chlorophylls, carotenoids, plastoquinones, and manganeses. In the chloroplasts of higher plants, PSII complexes and the associated light-harvesting antenna complex LHCII are not present throughout the thylakoid membranes but are abundant in the grana (2, 14). A densely packed array of PSII complexes in the grana was visualized by electron microscopy (8, 15). Grana formation is more prominent in shade leaves (or shade plants) than in sun leaves (or sun plants), so it has been suggested that enrichment of the PSII·LHCII complex in grana is a strategy of plants to collect excitation energy by PSII under weak light (16). The grana structure probably provides an organized environment for PSII. PSI and ATP synthase are located exclusively in the stroma-exposed thylakoids, including the stroma thylakoids, grana end membranes, and grana margins, because these complexes protrude into the stroma. Cytochrome b₆/f complexes without this protrusion are present uniformly throughout the thylakoids (3). It has been suggested that separation of PSI and PSII complexes on the thylakoids through grana formation is important to prevent “spillover” of excitation energy from PSII to PSI, which lowers photosynthesis efficiency (17).An active PSII complex comprises a homodimer of PSII monomers (13). When thylakoids are exposed to excessive visible light, the PSII dimer dissociates into two monomers (18), but the most significant change takes place inside the monomeric PSII, where the reaction center-binding D1 protein is photodamaged and degraded by specific proteases (19, 20). The photodamage to the D1 protein is a photooxidative process. This is caused by reactive oxygen species (ROS), most probably singlet oxygen (¹O₂) or the hydroxyl radical (HO^•) produced by overreduction of the acceptor side of PSII under excessive illumination or by endogenous cationic radicals, such as the oxidized forms of the primary electron donor P680 and the secondary electron donor Tyr_Z (Tyr¹⁶¹ of D1) to PSII (21). Strong illumination of the grana may readily cause damage to the PSII complexes by ROS and endogenous cationic radicals, because the grana is rich in PSII complexes. Segregation of PSI and PSII in the stacked thylakoids should make the electron transport between PSI and PSII a rate-limiting step in the electron flow, and overexcitation of PSII under these conditions may stimulate ROS production at the acceptor side of PSII. Close association of LHCII with the PSII core complexes should also stimulate ROS generation in the grana. Unstacking of the thylakoids, which is also expected to lead to random distribution of PSI and PSII on the thylakoids and dissociation of the LHCII from the PSII core, may be important to avoid photodamage to PSII.In the proteolysis of the damaged D1 protein in the chloroplasts of higher plants, the N-terminal Thr of the D1 protein is dephosphorylated, and the subsequent degradation produces 23- and 9-kDa fragments as the primary cleavage products (19, 20). The protease(s) and phosphatase(s) involved in these steps are presumably localized in the stroma thylakoids, grana end membranes, and grana margin. Lateral migration of the damaged PSII complexes from the grana to the membrane regions where the damaged PSII complexes are repaired is therefore important for degradation of the D1 protein. Thylakoid unstacking, if it occurs under light stress, should stimulate diffusion of the protein complexes on the thylakoids, thereby stimulating D1 turnover.First, we examined if excessive visible light can induce unstacking of the thylakoids. Second, we studied the effects of strong illumination on stacked and unstacked thylakoids to see if they showed different responses to excessive light. We strongly suggest that unstacking of the thylakoids caused by light stress is necessary to avoid further photodamage to the D1 protein and to facilitate degradation and removal of the photodamaged D1 protein from PSII complexes.     

Relationship between anthropometric measures and body composition among Muslim females of West Bengal, India

The human body composition is assessed to determine percent body fat (PBF), fat mass (FM), and lean body mass or fat free mass (FFM). The topological distribution of body fat has been the subject of many studies in the world and India. To the best of our knowledge the present paper is the first report on the body composition in terms of PBF and FM, and their relationship with anthropometric measures in Muslim females in India. The present study examines anthropometric measurements and their relationship with the body composition among Muslim females of West Bengal, India. A cross-sectional study of 100 female, Muslim students of Howrah and Kolkata was undertaken to compare the relationships of biceps and triceps skinfold, waist, hip and upper arm circumference, waist hip ratio and conicity index with their body composition variables (PBF and FM). All anthropometric measures displayed significant (p < 0.05) correlation with body composition measures. The triceps skinfold, however, demonstrated a significant correlation with PBF (r = 0.90) and FM (r = 0.93). The greatest amount of variation of PBF (81.3 %) and FM (89.2 %) was explained by the triceps skinfold. In addition, a considerable amount of variation of PBF (72.8 %) and FM (86.0 %) was explained by the mid upper arm circumference. In conclusion, the present study displays a tendency of regional adiposity in the upper arm, triceps skinfold and mid upper arm circumference are much more strongly associated with body fat.     

Correction to: Music of metagenomics—a review of its applications,analysis pipeline,and associated tools

Functional & Integrative Genomics -     

Identification and partial characterization of a highly active and stable phospholipase D from Brassica juncea seeds

Phospholipase D (PLD) activity has been identified in some new plant sources i.e. Brassica juncea (mustard) seeds, Zingibar officinale (ginger) rhizomes and Azadirachta indica (neem) leaves with the aim of identifying PLDs that possess high catalytic activity and stability. PLD from mustard seeds (PLD(ms)) exhibited the highest PLD specific activity, which was highly pH and temperature tolerant. PLD(ms) unlike many plant PLDs exhibited high thermal stability. The activity of PLD(ms) is optimum in the millimolar concentration of calcium ions and is independent of phosphatidylinositol-4,5-bisphosphate (PIP2). An active and stable enzyme like PLD(ms) may be utilized in the lipid industry.