Evidence for the Involvement of Tyrosine Kinase ZAP 70 in Nuclear Retinoid Receptor-dependent Transactivation in T Lymphocytes

Pharmacogenetics of steroid-responsive acute graft-versus-host disease

Glucocorticoids are central to effective therapy of acute graft-versus-host disease (GVHD). However, only about half of the patients respond to steroids in initial therapy. Based on postulated mechanisms for anti-inflammatory effectiveness, we explored genetic variations in glucocorticoid receptor, co-chaperone proteins, membrane transporters, inflammatory mediators, and variants in the T-cell receptor complex in hematopoietic cell transplant recipients with acute GVHD requiring treatment with steroids and their donors toward response at day 28 after initiation of therapy. A total of 300 recipient and donor samples were analyzed. Twenty-three SNPs in 17 genes affecting glucocorticoid pathways were included in the analysis. In multiple regression analysis, donor SNP rs3192177 in the ZAP70 gene (O.R. 2.8, 95% CI: 1.3-6.0, P=.008) and donor SNP rs34471628 in the DUSPI gene (O.R. 0.3, 95% CI: 0.1-1.0, P=.048) were significantly associated with complete or partial response. However, after adjustment for multiple testing, these SNPs did not remain statistically significant. Our results, on this small, exploratory, hypothesis generating analysis suggest that common genetic variation in glucocorticoid pathways may help identify subjects with differential response to glucocorticoids. This needs further assessment in larger datasets and if validated could help identify subjects for alternative treatments and design targeted treatments to overcome steroid resistance.

Monitoring the immune response to vaccination with an inactivated vaccine associated to bovine neonatal pancytopenia by deep sequencing transcriptome analysis in cattle

Bovine neonatal pancytopenia (BNP) is a new fatal, alloimmune/alloantibody mediated disease of new-born calves induced by ingestion of colostrum from cows, which had been vaccinated with a specific vaccine against the Bovine Virus Diarrhoea Virus (BVDV). The hypothesis of pathogenic MHC class I molecules in the vaccine had been put up, but no formal proof of specific causal MHC class I alleles has been provided yet. However, the unique features of the vaccine obviously result in extremely high specific antibody titres in the vaccinated animals, but apparently also in further molecules inducing BNP. Thus, a comprehensive picture of the immune response to the vaccine is essential. Applying the novel approach of next generation RNA sequencing (RNAseq), our study provides a new holistic, comprehensive analysis of the blood transcriptome regulation after vaccination with the specific BVDV vaccine. Our RNAseq approach identified a novel cytokine-like gene in the bovine genome that is highly upregulated after vaccination. This gene has never been described before in any other species and might be specific to ruminant immune response. Furthermore, our data revealed a very coordinated immune response to double-stranded (ds) RNA or a dsRNA analogue after vaccination with the inactivated single-stranded (ss) RNA vaccine. This would suggest either a substantial contamination of the vaccine with dsRNA from host cells after virus culture or a dsRNA analogue applied to the vaccine. The first option would highlight the potential risks associated with virus culture on homologous cells during vaccine production; the latter option would emphasise the potential risks associated with immune stimulating adjuvants used in vaccine production.

LIM kinase 1 - dependent cofilin 1 pathway and actin dynamics mediate nuclear retinoid receptor function in T lymphocytes

Background

It is known that retinoid receptor function is attenuated during T cell activation, a phenomenon that involves actin remodeling, suggesting that actin modification may play a role in such inhibition. Here we have investigated the role of actin dynamics and the effect of actin cytoskeleton modifying agents on retinoid receptor-mediated transactivation.

Results

Agents that disturb the F-actin assembly or disassembly attenuated receptor-mediated transcription indicating that actin cytoskeletal homeostasis is important for retinoid receptor function. Overexpression or siRNA-induced knockdown of cofilin-1 (CFL1), a key regulator of F-actin assembly, induced the loss of receptor function. In addition, expression of either constitutively active or inactive/dominant-negative mutants of CFL1or CFL1 kinase LIMK1 induced loss of receptor function suggesting a critical role of the LIMK1-mediated CFL1 pathway in receptor-dependent transcription. Further evidence of the role of LMK1/CFL1-mediated actin dynamics, was provided by studying the effect of Nef, an actin modifying HIV-1 protein, on receptor function. Expression of Nef induced phosphorylation of CFL1 at serine 3 and LIMK1 at threonine 508, inhibited retinoid-receptor mediated reporter activity, and the expression of a number of genes that contain retinoid receptor binding sites in their promoters. The results suggest that the Nef-mediated inhibition of receptor function encompasses deregulation of actin filament dynamics by LIMK1 activation and phosphorylation of CFL1.

Conclusion

We have identified a critical role of LIMK1-mediated CFL1 pathway and actin dynamics in modulating retinoid receptor mediated function and shown that LIMK1-mediated phosphocycling of CFL1 plays a crucial role in maintaining actin homeostasis and receptor activity. We suggest that T cell activation-induced repression of nuclear receptor-dependent transactivation is in part through the modification of actin dynamics.

Expression level of lipoprotein lipase and dystrophin genes predict survival in B-cell chronic lymphocytic leukemia

Mutational status of immunoglobulin variable region genes (VH-genes) is known as the strongest predictor of long term prognosis in B-CLL. However, applications in the routine clinical practice are time consuming, and therefore some other predictions are required. In this study, we have compared prognostic values of real time PCR quantification of the expression levels of four genes previously shown to be differentially expressed in V(H)-unmutated and mutated B-CLL subtypes: ZAP-70, ZBTB20, DMD and LPL. The study included 134 B-CLL patients. Expression levels of LPL and DMD genes were significantly correlated to mutational status, while expression levels of of ZAP-70 gene correlated only in CD19+ selected cases (N = 40). No correlation was observed for ZBTB20 gene. Expression levels of LPL and DMD predicted overall survival in the entire cohort of patients. Prognostic values of LPL gene expression levels were significant even for CLL patients with stage A. Quantitative RT-PCR assays for measuring LPL gene expression are robust enough to be introduced into routine clinical practice.

Zap70 Signaling Pathway Mediates Glucocorticoid Receptor-Dependent Transcriptional Activation: Role in the Regulation of Annexin 1 Expression in T Cells

We have recently shown that Zap70 is important in retinoid receptor-dependent transactivation in T lymphocytes. We report that Zap70 signaling is also essential in dexamethasone-inducible glucocorticoid receptor (GR)-mediated transactivation in T lymphocytes. Zap70-negative Jurkat T cells and cells reconstituted with inactive Zap70 exhibited attenuated GR-mediated activation as compared with Zap70 reconstituted and wild-type cells. Lck-lacking Jurkat cells were also found to show markedly reduced GR activation, and reconstitution with Lck restored the activation. Gene array and protein analysis showed that the level of annexin 1 (ANXA1), an anti-inflammatory protein known to be induced and released by the glucocorticoid action, was significantly reduced in Zap70-negative and Zap70-inactive Jurkat cells as compared with wild-type cells. Lck-lacking cells were also found to have markedly reduced ANXA1 levels and reconstitution with Lck restored the ANXA1 expression. RNA interference-induced knockdown of Zap70 or Lck in Jurkat cells and peripheral blood T lymphocytes also resulted in the loss of ANXA1 expression. Transcriptional analysis revealed that dexamethasone-inducible GR-mediated activation of ANXA1 promoter was compromised in both Zap70 knocked down peripheral blood T cells and Zap70 or Lck-deficient/Lck-inactive Jurkat cells, indicating an essential role of these kinases in GR-mediated ANXA1 promoter activation in T lymphocytes. To summarize, our data demonstrate an important role for Zap70 signaling in GR-mediated transactivation in T lymphocytes and also point out a crucial role of this kinase in maintaining normal ANXA1 levels in these cells.

Transcriptome of local innate and adaptive immunity during early phase of infectious bronchitis viral infection

To understand the mechanistic basis of local innate and adaptive immunity against infectious bronchitis virus (IBV) at the molecular level, we examined the gene transcription profile of tracheal epithelial layers 3 d after infection of chickens with an attenuated IBV-Massachusetts strain. Results suggested that the transcription levels of 365 genes were either upregulated or downregulated (2-fold and higher) after IBV infection. Among the upregulated 250 genes, 25 were directly immune-related genes. These upregulated immune response genes included TLR2, TLR3, interferon-induced antiviral genes (Mx), and genes responsible for cytotoxic T cell killing such as Fas antigen and granzyme-A. Overall, a diversity of innate immunity and helper T cell type 1 (Th1)-biased adaptive immunity are activated in the host's early defense against IBV invasion, and they are responsible for the rapid clearance of virus from the local infection.