Natural killer cell accumulation in tumors is dependent on IFN-gamma and CXCR3 ligands

Several studies have correlated high numbers of tumor-infiltrating natural killer (NK) cells with a good prognosis for cancer patients. Our study aimed at identifying factors controlling intratumoral NK cell accumulation in s.c. injected NK cell sensitive tumor models and at studying their effect on survival time of recipient mice. We observed that fewer NK cells infiltrated the tumors in IFN-gamma receptor knockout (IFN-gammaR(-/-)) mice compared with wild-type controls that correlated with decreased survival rate. Exogenous application of IFN-gamma in the tumor augmented levels of ligands of the chemokine receptor CXCR3, increased NK cell accumulation, and prolonged survival. Furthermore, our data show that CD27(high) NK cells, which under steady-state conditions express CXCR3, preferentially accumulated in the tumor tissue. Accordingly, significantly lower numbers of tumor-infiltrating NK cells were detected in CXCR3(-/-) mice, and the capacity of adoptively transferred CXCR3(-/-) NK cells to accumulate in the tumor was severely impaired. Finally, exogenous application of the CXCR3 ligand CXCL10 in the tumor or ectopic expression of CXCL10 by tumor cells increased the numbers of NK cells in the tumors and prolonged NK cell-dependent survival. Our results identify IFN-gamma and the expression of CXCR3 on NK cells as prerequisites for NK cell infiltration into tumors. Exploiting strategies to augment NK cell accumulation in the tumor might lead to the development of effective antitumor therapies.     

Regulatory T cells control macrophage accumulation and activation in lymphoma

Strategies of manipulating immunosuppressive regulatory T cells (Treg) in cancer patients are currently evaluated in clinical trials. Treg suppress immune responses of tumor‐specific T cells; yet, relatively little is known about the impact of Treg on innate immune cells in tumor models in vivo. Many tumors lose expression of MHC class I. Therefore, our study aimed at defining strategies to strengthen immune responses against a high tumor burden of the MHC class I‐deficient mouse lymphoma RMA‐S. We demonstrate that Treg depletion in mice led to tumor rejection that was dependent on T cells, NK cells and IFN‐γ. In the absence of Treg elevated levels of IFN‐γ were produced by tumor‐infiltrating T cells and NK cells. Tumor rejection observed in the absence of Treg correlated with a substantial IFN‐γ‐dependent increase in the numbers of tumor‐infiltrating leukocytes. The most abundant cell population in the tumors was macrophages. Tumor‐infiltrating macrophages from Treg‐depleted mice expressed increased amounts of MHC class II, produced highly enhanced levels of pro‐inflammatory cytokines and inhibited tumor cell proliferation. It was reported that tumor‐infiltrating macrophages have multi‐faceted functions promoting or counteracting tumor growth. In our study, high numbers of macrophages infiltrating RMA‐S tumors in the absence of Treg correlated with tumor rejection suggesting that macrophages are additional targets for Treg‐mediated immune suppression in cancer.     

An unrestrained proinflammatory M1 macrophage population induced by iron impairs wound healing in humans and mice

Uncontrolled macrophage activation is now considered to be a critical event in the pathogenesis of chronic inflammatory diseases such as atherosclerosis, multiple sclerosis, and chronic venous leg ulcers. However, it is still unclear which environmental cues induce persistent activation of macrophages in vivo and how macrophage-derived effector molecules maintain chronic inflammation and affect resident fibroblasts essential for tissue homeostasis and repair. We used a complementary approach studying human subjects with chronic venous leg ulcers, a model disease for macrophage-driven chronic inflammation, while establishing a mouse model closely reflecting its pathogenesis. Here, we have shown that iron overloading of macrophages--as was found to occur in human chronic venous leg ulcers and the mouse model--induced a macrophage population in situ with an unrestrained proinflammatory M1 activation state. Via enhanced TNF-α and hydroxyl radical release, this macrophage population perpetuated inflammation and induced a p16(INK4a)-dependent senescence program in resident fibroblasts, eventually leading to impaired wound healing. This study provides insight into the role of what we believe to be a previously undescribed iron-induced macrophage population in vivo. Targeting this population may hold promise for the development of novel therapies for chronic inflammatory diseases such as chronic venous leg ulcers.     

Elevated blood markers 1 year before manifestation of malignant glioma

We detected distinct plasma concentration profiles of S100B, neuropeptide Y, and secretagogin in 3 of 191 patients enrolled in a previous study investigating brain-tissue–related markers in the blood of patients with atrial fibrillation. Intriguingly, 2 of these 3 patients, both of whom were without neurological symptoms at the time of blood sampling, were diagnosed with malignant glioma (MG) approximately 1 year later. To our knowledge, this is the first report indicating that distinct blood biomarker profiles may be detected long before clinical manifestation of MG.     

Evaluation of subcutaneous glucose monitoring systems under routine environmental conditions in patients with type 1 diabetes

Continuous and flash glucose monitoring (GM) systems have been established in diabetes care. We compared the sensor performance of 3 commercially available GM systems. A total of 12 patients with type 1 diabetes were included in a single‐centre, open‐label study in which the sensor performance of the Abbott FreeStyle libre (Abbott), Dexcom G4 Platinum (Dexcom) and Medtronic MiniMed 640G (Medtronic) systems over 12 hours was compared during mimicked real‐life conditions (meals, exercise, hypo‐ and hyperglycaemia). Sensor performance was determined by fulfilment of ISO 15197:2013 criteria, calculating mean absolute relative difference (MARD), and was also illustrated using Parkes error grid and Bland–Altman plots. Sensor performance during changes in metabolic variables (lactate, betahydroxybutyrate, glucagon, non‐esterified‐fatty‐acids) was determined by Spearman's rank correlation coefficient testing. The systems fulfilled ISO 15197:2013 criteria by 73.2% (Abbott), 56.1% (Dexcom) and 52.0% (Medtronic). The MARDs ± standard deviation in the entire glycaemic range were 13.2% ± 10.9% (Abbott), 16.8% ± 12.3% (Dexcom) and 21.4% ± 17.6% (Medtronic), respectively. All sensors performed less accurately during hypoglycaemia and best during hyperglycaemia. We did not observe an influence of metabolic variables on sensor performance.     

Differential tissue expression and activation of p38 MAPK α, β, γ, and δ isoforms in rheumatoid arthritis

Objective

Activation of p38 MAPK is a key signaling step in chronic inflammation. Inhibition of p38 MAPK is considered to be a promising future strategy to control inflammatory diseases, but studies of compounds to inhibit this kinase have so far been limited to investigation of their side effects. We undertook the present study to investigate which specific molecule, among 4 different isoforms of p38 MAPK (α, β, γ, and δ), is predominantly expressed and activated in inflammation. Such knowledge could allow more specific targeting of p38 MAPK in inflammatory disease.

Methods

Studies were performed on inflamed tissue from patients with rheumatoid arthritis, as a prototype of inflammatory disease. The expression and activation of the α, β, γ, and δ isoforms of p38 MAPK were examined by immunoblotting, immunoprecipitation, and immunohistochemistry.

Results

Immunoblot analysis revealed that α and γ were the predominantly expressed p38 MAPK isoforms, whereas the other 2 isoforms were less frequently present. By immunohistochemistry, the expression of all p38 MAPK isoforms was localized to the synovial lining layer as well as to blood vessels. Colabeling with cell‐specific markers revealed that macrophages expressed the α and γ isoforms, synovial fibroblasts the β and γ isoforms, and granulocytes the δ isoform, whereas T lymphocytes were rarely positive for any p38 MAPK isoform. Double‐labeling with isoform‐specific antibody and pan‐p38 antibody against the phosphorylated form of p38 MAPK showed activation of the α and γ isoforms. Occasional activation of the β isoform was also noted in the synovial lining and the endothelium, whereas the δ isoform, although expressed in pericytes around blood vessels, was not phosphorylated. This phosphorylation pattern was confirmed in immunoprecipitation studies in which activated p38 MAPK from synovial tissue extracts was identified as p38 MAPKα and ‐γ but not p38 MAPKβ or ‐δ.

Conclusion

These data show that the α and γ isoforms of p38 MAPK dominate in chronic inflammation. Effective strategies to inhibit p38 MAPK should therefore aim to specifically target either or both of these isoforms.

     

Evidence for tissue-specific cytosine-methylation of plastid DNA from Zea mays

Summary Total DNA isolated from leaves, etiolated seedlings, roots, endosperm or embryos of Zea mays was digested separately with each of the restriction enzymes HpaII, MspI and HhaI, and the resulting fragment patterns, which were specific for the plastid rRNA operon, were analyzed by Southern hybridization. While most of the fragment patterns were consistent with previously established physical maps, the partial resistance shown by one HpaII site and one HhaI site, both of which reside in the 16S/23S rDNA spacer region, was observed in DNA isolated from embryo, root tissue and endosperm. The partially resistant HpaII site was susceptible to cleavage with restriction enzyme MspI. From this and from the known inhibition of restriction enzyme Hhal at methylated HhaI sites, we conclude that the partial resistance of the two sites is caused by C-specific methylation of plastid DNA in the respective tissues. The tissue specificity of this DNA methylation is likely to reflect a differential expression of plastome encoded genes.     

Altered dimerization of metabotropic glutamate receptor 3 in schizophrenia.

BACKGROUND: Metabotropic glutamate receptors (mGlus) may be involved in the pathophysiology of schizophrenia. Group II mGlus (mGlu2 and mGlu3) have attracted considerable interest since the development of potent specific agonists that exhibit atypical antipsychotic-like activity and reports of a genetic association between the mGlu3 gene and schizophrenia. METHODS: In this postmortem study, mGlu3 protein levels in Brodmann area 10 of prefrontal cortex from schizophrenic (n = 20) and control (n = 35) subjects were analyzed by western immunoblotting using a novel specific mGlu3 antibody and an antibody for the vesicular glutamate transporter 1 (VGluT1). RESULTS: We report a significant decrease in the dimeric/oligomeric forms of mGlu3 in schizophrenic patients compared with control subjects, whereas total mGlu3 and VGluT1 levels were not altered significantly. CONCLUSIONS: This is the first experimental evidence that mGlu3 receptor levels are altered in schizophrenia and supports the hypothesis that neurotransmission involving this particular excitatory amino acid receptor is impaired in schizophrenia.