Colitogenic role of tumour necrosis factor (TNF) receptors in trinitrobenzene sulphonic acid colitis: TNF-R1 ablation does not affect systemic inflammatory response

Tumour necrosis factor (TNF)-α plays a critical role in the pathogenesis of T helper type 1-mediated colitis such as Crohn's disease. However, the roles of its two receptors in mediating pathology remain largely unknown. In this study, trinitrobenzene sulphonic acid (TNBS) was used to induce colitis in TNF-receptor single or double knock-out (DKO) BALB/c mice and in wild-type counterparts. TNF-R1(-/-) mice had significantly less weight loss, reduced mortality, colon shortening and oedema, colon histological damage and lower levels of colon myeloperoxidase compared with wild-type (WT) BALB/c mice. A similar manifestation was also observed in TNF-R2(-/-) and TNF-R1(-/-) TNF-R2(-/-) (TNF-R DKO) mice. Strikingly, systemic inflammatory response (including splenomegaly and monocyte expansion) was found in WT and TNF-R1(-/-) mice after TNBS, instead of TNF-R2(-/-) and TNF-R DKO mice. Attenuated pathology of colitis in TNF-R1(-/-) or TNF-R2(-/-) mice correlated with lower amounts of interleukin (IL)-6, IL-1β, monocyte chemotactic protein (MCP)-1, IL-12p70 and interferon (IFN)-γ production in the colons. Importantly, ablation of TNF-R1 or TNF-R2 reduced the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling (TUNEL)-positive apoptotic epithelial cells in the affected colons compared with WT TNBS-instilled controls, which might be due to the heightened ratio of Bcl-2/Bax and reduced activity of nuclear factor (NF)-κB. These findings suggest that either TNF-R1 or TNF-R2 plays a pathogenic role in the pathology of colitis and TNF signalling via TNF-R1 or TNF-R2 alone is not sufficient for inducing mucosal damage.

Meta-analysis: the significance of screening for JAK2V617F mutation in Budd-Chiari syndrome and portal venous system thrombosis

BACKGROUND

It is important to evaluate whether screening for JAK2V617F mutation should be routinely performed in patients with Budd-Chiari syndrome (BCS) and portal venous system thrombosis (PVST). However, the prevalence of JAK2V617F mutation in such patients is substantially varied, and its association with development of myeloproliferative disorders (MPD) is deficiently identified.

AIMS

To estimate the prevalence of JAK2V617F mutation and to explore the significance of screening for JAK2V617F mutation in these patients.

METHODS

All observational studies regarding the prevalence of JAK2V617F mutation in patients with BCS and PVST were identified via PubMed and MEDLINE databases. Primary items were the proportions of JAK2V617F mutation and MPD.

RESULTS

Twenty-three studies fulfilled the inclusion criteria. Regardless of underlying aetiological factors, the pooled prevalence of JAK2V617F mutation was 37% and 24% in patients with BCS and PVST respectively. After pre-existing MPD was excluded, the pooled prevalence was decreased to 26% and 19%. Heterogeneity among studies was significant for the prevalence of JAK2V617F mutation. Compared with healthy subjects and patients with thrombosis in other sites, the prevalence of JAKV617F mutation was significantly higher in patients with BCS and PVST. The prevalence of MPD was significantly higher in patients with JAK2V617F mutation than those without.

CONCLUSIONS

JAK2V617F mutation is frequently found in patients with BCS and PVST, but there is a huge variation of prevalence among the included studies. Additionally, it is more specific to thrombosis in splanchnic areas and strongly associated with the development of MPD in these patients. Further studies are needed to evaluate whether the screening test should be widely performed in Asian countries and cirrhotic patients.

Effect of maternal undernutrition on vascular expression of micro and messenger RNA in newborn and aging offspring

The aim of this study was to test the hypothesis that maternal undernutrition (MUN) alters offspring vascular expression of micro-RNAs (miRNAs), which, in turn, could regulate the expression of a host of genes involved with angiogenesis and extracellular matrix remodeling. The expression of miRNA and mRNA in the same aortic specimens in 1-day-old (P1) and 12-mo-old offspring aortas of dams, which had 50% food restriction from gestation day 10 to term, was determined by specific rat miRNA and DNA arrays. MUN significantly downregulated the expression of miRNAs 29c, 183, and 422b in the P1 group and 200a, 129, 215, and 200b in the 12-mo group, and upregulated the expression of miRNA 189 in the P1 group and 337 in the 12-mo group. The predicted target genes of the miRNAs altered in the two age groups fell into the categories of: 1) structural genes, such as collagen, elastin, and enzymes involved in ECM remodeling; and 2) angiogenic factors. MUN primarily altered the expression of mRNAs in the functional category of cell cycle/mitosis in the P1 group and anatomic structure and apoptosis in the 12-mo age group. Several of the predicted target genes of miRNAs altered in response to MUN were identified by the DNA array including integrin-beta(1) in the P1 aortas and stearoyl-CoA desaturase-1 in the 12-mo age groups. These results are consistent with the hypothesis that MUN modulation of offspring gene expression may be mediated in part by a miRNA mechanism.

The pathogenic role of interleukin-27 in autoimmune diabetes

Interleukin (IL)-27 is an IL-12-related cytokine that can promote both anti- and pro-inflammatory immune responses. This study investigated the potential role of IL-27 in autoimmune diabetes. We detected a high level of IL-27 in diabetic NOD mice. In addition, blockade of IL-27 significantly delayed the onset of diabetic splenocyte-transferred diabetes, while IL-27-treated diabetic splenocytes promoted the onset of the disease, compared with untreated controls. Furthermore, IL-27 up-regulated pro-inflammatory cytokines IFN-gamma and IL-17 and down-regulated anti-inflammatory cytokines IL-4, TGF-beta, and IL-10 secreted by diabetic splenocytes. These results demonstrate a pathogenic role of IL-27 in T cell-mediated autoimmune diabetes.

Controlled trials in hepatitis B virus-related decompensate liver cirrhosis: peripheral blood monocyte transplant versus granulocyte-colony-stimulating factor mobilization therapy

BACKGROUND

Liver cirrhosis represents the end stage of chronic liver injury. Currently, liver transplantation provides the only definite cure but it is beset with many problems, including lack of donors and risk of rejection. Stem cell therapy is very attractive in this setting because it has the potential to help tissue regeneration. In this study, we aimed to investigate the therapeutic effect of peripheral blood monocyte cell (PBMC) transplantation in decompensated liver cirrhosis.

METHODS

A total of 40 subjects (31 men and nine females, age range 21-71 years) was recruited to two groups. Group 1 received granulocyte-colony-stimulating factor (G-CSF) mobilization, PBMC collection by leukapheresis and PBMC transplant therapy. Group 2 received G-CSF mobilization for 4 days. At baseline and 6 months after treatment, liver function of the two groups was monitored by blood examination and ultrasonagraphy.

RESULTS

Both groups gained significant improvement in liver synthetic function, such as serum albumin and prothrombin time, from baseline to 6 months after treatment (P<0.01). However, there was no significant difference in alanine aminotransferase, aspartate aminotransferase and total bilirubin in both groups (P>0.05). Compared with group 2, a significantly improved liver function was observed in group 1, including elevated serum albumin level and a decreased CTP score (P<0.05). No major adverse effects were noted.

DISCUSSION

Autologous PBMC transplantation could be considered as a novel and alternative treatment for patients with decompensated liver cirrhosis.

Mechanisms underlying B-cell tolerance induction by antigen-immunoglobulin G gene transfer

Previous studies on the mechanisms underlying tolerance induction in diabetes have mainly focused on T cells, however B cells also have an important role in diabetes. Based on our previous studies that splenocytes, transduced with glutamic acid decarboxylase (GAD) 65 fused to immunoglobulin (Ig) G carrier, reduced antibody-mediated response in non-obese diabetic (NOD) mice, here we examined the mechanisms underlying B-cell tolerance in this system. We found that GAD-IgG-transduced splenocytes did not reduce CD40 expression on B-cells in NOD mice, but they did downregulate CD40 ligand (CD40L) expression. Furthermore, anti-CD40L injection reduced autoantibody levels in NOD mice and in vitro experiments demonstrated that CD40L blockade reduced the antigenpresenting capability of B-cells. In conclusion, the results of this study suggest that downregulation of CD40L may be one mechanism underlying the induction of B-cell tolerance in GAD-IgG-treated NOD mice.

Mechanisms of regulatory T-cell induction by antigen-IgG-transduced splenocytes

Our previous studies have demonstrated that splenocytes, transduced with glutamate decarboxylate 65 (GAD) and IgG fusion construct, protect non-obese diabetes (NOD) mice from diabetes. However, the mechanism by which this strategy prevents diabetes is not well understood. Here, we found that CD4(+)Foxp3(+)Treg cells, in vitro induced by GAD-IgG-transduced splenocytes, after transfer, were responsible for prevention of diabetes in NOD mice. Further studies suggested that GAD-IgG-transduced B cells could secrete high level of TGF-beta and stimulated CD4(+)T cells to secrete high level of IFN-gamma. Finally, we found that when TGF-beta and/or IFN-gamma were blocked, CD4(+)Foxp3(-)T cells were not converted into CD4(+)Foxp3(+)Treg cells. The results suggest that GAD-IgG-transduced B cells via TGF-beta and IFN-gamma in vitro induce the CD4(+)Foxp3(+)Treg cells which are responsible for prevention of diabetes in NOD mice by GAD-IgG-gene transfer.

Cerebellar pleomorphic xanthoastrocytoma in a patient with neurofibromatosis type 1

We describe a case of cerebellar pleomorphic xanthoastrocytoma (PXA) occurring in a patient with neurofibromatosis type 1 (NF1). The histomorphology of this uncommon glial (astrocytic) neoplasm is discussed. The occurrence of this tumor within the posterior fossa is extremely rare. To our knowledge, this is the first reported case of a cerebellar PXA in a patient with NF1.

Blockade of melanocortin transmission inhibits cocaine reward

Melanocortins and the melanocortin-4 receptor (MC4-R) are enriched in the nucleus accumbens, a brain region that has been implicated in the rewarding action of cocaine and other drugs of abuse. In the present study we use a number of rat behavioral models to show that infusion of a melanocortin peptide antagonist into the nucleus accumbens blocks the reinforcing, incentive motivational, and locomotor sensitizing effects of cocaine. We also show that locomotor responses to repeated cocaine exposure are completely blocked in MC4-R null mutant mice and reduced in Agouti mice that overexpress an endogenous inhibitor of melanocortins in the brain. The results also demonstrate that cocaine administration increases the expression of MC4-R in the nucleus accumbens and striatum, and that MC4-R is co-localized with prodynorphin in medium spiny neurons in the nucleus accumbens. Together, these findings indicate that the behavioral actions of cocaine are dependent on activation of MC4-R, and suggest that upregulation of this receptor by drug exposure may contribute to sensitization of these behavioral responses. Modulation of cocaine reward is a novel action of the melanocortin-MC4-R system and could be targeted for the development of new medications for cocaine addiction.

Cationic niosomes as gene carriers: preparation and cellular uptake in vitro

Cationic niosomes of sorbitan monoesters were prepared using film hydration method and tested for their effect on delivery of antisense oligonucleotides (OND) in a COS-7 cell line. These formulations showed positive results on cellular uptake of antisense oligonucleotides. Especially, cationic niosomes of Span 40 and 60 have a more significant effect.

Retroviral delivery of GAD-IgG fusion construct induces tolerance and modulates diabetes: a role for CD4+ regulatory T cells and TGF-beta?

Previous studies have demonstrated that antigen-specific tolerance could be induced by lipopolysaccharide (LPS)-stimulated B cells retrovirally transduced with an immunoglobulin-antigen (or epitope-containing peptide) fusion construct. To investigate the mechanism of this gene therapy system, we now adapted this approach to immunotherapy of spontaneous diabetes in nonobese diabetic (NOD) mice, a T-cell-mediated autoimmune disease triggered, in part, by a pathogenic response to glutamate decarboxylase (GAD) 65. We demonstrate that LPS-stimulated splenocytes, retrovirally transfected with GAD-IgG fusion construct, induce a significant antigen-specific hyporesponsiveness at both cellular and humoral levels and reduce the incidence of diabetes in female NOD mice. Parallel with disease protection, we observed a prolonged increase of the numbers of CD4+CD25+ T cells in the periphery of GAD-IgG-treated mice, compared to those treated with a control IgG vector, both in the prediabetic period and persisting even 8 months after gene therapy. This increase appeared to be induced by the repeated stimulation of the antigen in the periphery instead of a result of differentiation of T-cell precursor in the thymus. Moreover, CD4+CD25+ T cells induced by GAD-IgG fusion construct were capable of suppressing the proliferative response of CD4+CD25- T cells in vitro; and ablation of the activity of CD4+CD25+ T cells by blocking antibody against CD25 could reverse GAD-specific T-cell hyporesponsiveness. These results suggested that CD4+CD25+ T-cell subset induced in GAD-IgG-treated NOD mice represented the regulatory or suppressive CD4+CD25+ T cells (Treg) and might play an important role in the induction and maintenance of tolerance in NOD mice. Furthermore, the numbers of splenic CD4+CD62L+ regulatory T cells in GAD-IgG-treated mice during the prediabetic period and serum TGF-beta levels in 34-38-week-old GAD-IgG-protected mice were also increased, compared to control IgG-treated ones. Therefore, we propose that the induction of tolerance and the prevention of diabetes incidence in NOD female mice induced by the GAD-IgG fusion construct may require CD4+ regulatory T cells, and the possible mediation of TGF-beta.