Modulation of central endocannabinoid system results in gastric mucosal protection in the rat.

Previous findings showed that inhibitors of fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), degrading enzymes of anandamide (2-AEA) and 2-arachidonoylglycerol (2-AG), reduced the nonsteroidal anti-inflammatory drug-induced gastric lesions. The present study aimed to investigate: i./whether central or peripheral mechanism play a major role in the gastroprotective effect of inhibitors of FAAH, MAGL and AEA uptake, ii./which peripheral mechanism(s) may play a role in mucosal protective effect of FAAH, MAGL and uptake inhibitors. METHODS: Gastric mucosal damage was induced by acidified ethanol. Gastric motility was measured in anesthetized rats. Catalepsy and the body temperature were also evaluated. Mucosal calcitonin gene-related peptide (CGRP), somatostatin concentrations and superoxide dismutase (SOD) activity were measured. The compounds were injected intraperitoneally (i.p.) or intracerebroventricularly (i.c.v.). RESULTS: 1. URB 597, JZL184 (inhibitors of FAAH and MAGL) and AM 404 (inhibitor of AEA uptake) decreased the mucosal lesions significantly given either i.c.v. or i.p. 2. URB 937, the peripherally restricted FAAH inhibitor failed to exert significant action injected i.p. 3. Ethanol-induced decreased levels of mucosal CGRP and somatostatin were reversed by URB 597, JZL 184 and AM 404, the decreased SOD activity was elevated significantly by URB 597 and JZL 184. 4. Neither compounds given i.c.v. influenced gastric motility, elicited catalepsy, or hypothermia. CONCLUSION: Elevation of central endocannabinoid levels by blocking their degradation or uptake via stimulation of mucosal defensive mechanisms resulted in gastroprotective action against ethanol-induced mucosal injury. These findings might suggest that central endocannabinoid system may play a role in gastric mucosal defense and maintenance of mucosal integrity

Exotoxin A eEF2 complex structure indicates ADP ribosylation by ribosome mimicry

The bacteria causing diphtheria, whooping cough, cholera and other diseases secrete mono ADP ribosylating toxins that modify intracellular proteins. Here, we describe four structures of a catalytically active complex between a fragment of Pseudomonas aeruginosa exotoxin A ETA and its protein substrate, translation elongation factor 2 eEF2 . The target residue in eEF2, diphthamide a modified histidine , spans across a cleft and faces the two phosphates and a ribose of the non hydrolysable NAD analogue, amp; 946;TAD. This suggests that the diphthamide is involved in triggering NAD cleavage and interacting with the proposed oxacarbenium intermediate during the nucleophilic substitution reaction, explaining the requirement of diphthamide for ADP ribosylation. Diphtheria toxin may recognize eEF2 in a manner similar to ETA. Notably, the toxin bound amp; 946;TAD phosphates mimic the phosphate backbone of two nucleotides in a conformational switch of 18S rRNA, thereby achieving universal recognition of eEF2 by ET

Epigenetic regulation of CIITA expression in human T-cells

In humans, T-cells accomplish expression of MHC-II molecules through induction of CIITA upon activation. Here we show that CIITA promoter accessibility in T-cells is epigenetically regulated. In unstimulated T-cells, CIITA-PIII chromatin displays relative high levels of repressive histone methylation marks (3Me-K27-H3 and 3Me-K20-H4) and low levels of acetylated histones H3 (Ac-H3) and H4 (Ac-H4). These repressive histone marks are replaced by histone methylation marks associated with transcriptional active genes (3Me-K4-H3) and high levels of Ac-H3 and Ac-H4 in activated T-cells. This is associated with concomitant recruitment of RNA polymerase II. In T-leukemia cells, devoid of CIITA expression, similar repressive histone methylation marks and low levels of acetylated histone H3 correlated with lack of CIITA expression. This in contrast to CIITA expressing T-lymphoma cells, which display high levels of Ac-H3 and 3Me-K4-H3, and relative low levels of the 3Me-K27-H3 and 3Me-K20-H4 marks. Of interest was the observation that the levels of histone acetylation and methylation modifications in histones H3 and H4 were also noted in chromatin of the downstream CIITA-PIV promoter as well as the upstream CIITA-PI and CIITA-PII promoters both in normal T-cells and in malignant T-cells. Together our data show that CIITA chromatin in T-cells expressing CIITA display similar histone acetylation and methylation characteristics associated with an open chromatin structure. The opposite is true for T-cells lacking CIITA expression, which display histone modifications characteristic of condensed chromatin.Stemcel biology/Regenerative medicine (incl. bloodtransfusion

Epigenetic control of CCR5 transcript levels in immune cells and modulation by small molecules inhibitors

Previously, we have shown that CCR5 transcription is regulated by CREB-1. However, the ubiquitous pattern of CREB-1 expression suggests the involvement of an additional level of transcriptional control in the cell type-specific expression of CCR5. In this study we show that epigenetic changes (i.e. DNA methylation and histone modifications) within the context of the CCR5 P1 promoter region correlate with transcript levels of CCR5 in healthy and in malignant CD4(+) T lymphocytes as well as in CD14(+) monocytes. In normal naïve T cells and CD14(+) monocytes the CCR5 P1 promoter resembles a bivalent chromatin state, with both repressive and permissive histone methylation and acetylation marks. The CCR5 expressing CD14(+) monocytes however show much higher levels of acetylated histone H3 (AcH3) compared to the non-CCR5-expressing naïve T cells. Combined with a highly methylated promoter in CD14(+) monocytes, this indicates a dominant role for AcH3 in CCR5 transcription. We also show that pharmacological interference in the epigenetic repressive mechanisms that account for the lack of CCR5 transcription in T leukemic cell lines results in an increase in CREB-1 association with the CCR5 P1 chromatin. Furthermore RNA polymerase II was also recruited into CCR5 P1 chromatin resulting in CCR5 re-expression. Together, these data indicate that epigenetic modifications of DNA, and of histones, contribute to the control of CCR5 transcription in immune effector cells

Genotoxic evaluation of pirfenidone using erythrocyte rodent micronucleus assay

Background: We describe a family with a 7-year-old proband case diagnosed with systemic lupus erythematosus (SLE) plus secondary anti-phospholipid syndrome (APS) as well as two affected paternal aunts. We compared the frequency of these polymorphisms with healthy controls. Objectives: To evaluate the mode of inheritance in this familial case of APS and SLE and the possible association of plasminogen activator inhibitor-1 (PAI-1) -675 4G/5G and PAI-2 Ser413/Cys polymorphisms. To compare the genotype frequency of these polymorphisms with the results found in a Mexican Mestizo population. Methods: PAI-1 -675 4G/5G and PAI-2 Ser413/Cys were determined by the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique using Bsl I and Mwo I on four generations of the family studied. PAI-2 Ser413/Cys polymorphism was also determined in 50 healthy individuals of Mexican Mestizo origin. Results: The family pedigree demonstrated that this family did not follow a Mendelian inheritance pattern. When the PAI-2 Ser413/Cys polymorphism was examined, we found that 60% (3/5) of the relatives homozygous to Ser413/Ser were affected with SLE and/or APS (p = 0.027). The proband case was 4G/5G genotype for the PAI-1 -675 4G/5G polymorphism. No differences between healthy controls of the Mexican Mestizo population and the family studied for the PAI-2 Ser413/Cys polymorphism or PAI-1 -675 4G/5G polymorphisms were found. Conclusions: Our data indicate that this family did not follow the Mendelian inheritance pattern. The Ser413/Ser genotype demonstrated in 60% of the affected members (3/5) of this family might increase the risk for autoimmune syndromes such as APS or SLE. " 2007 Taylor & Francis on license from Scandinavian Rheumatology Research Foundation.",,,,,,"10.1080/03009740601089648",,,"http://hdl.handle.net/20.500.12104/41733","http://www.scopus.com/inward/record.url?eid=2-s2.0-34547493556&partnerID=40&md5=e7eac049d56035f38602789c05ffdbbf",,,,,,"3",,"Scandinavian Journal of Rheumatology",,"20