Local Tumor Treatment in Combination with Systemic Ipilimumab Immunotherapy Prolongs Overall Survival in Patients with Advanced Malignant Melanoma.

Immune checkpoint inhibition with ipilimumab has revolutionized cancer immunotherapy and significantly improved outcomes of patients with advanced malignant melanoma. Local peripheral treatments (LPT), such as radiotherapy or electrochemotherapy, have been shown to modulate systemic immune responses, and preliminary data have raised the hypothesis that the combination of LPT with systemic immune checkpoint blockade might be beneficial. Clinical data from 127 consecutively treated melanoma patients at four cancer centers in Germany and Switzerland were analyzed. Patients received either ipilimumab (n = 82) or ipilimumab and additional LPT (n = 45) if indicated for local tumor control. The addition of LPT to ipilimumab significantly prolonged overall survival (OS; median OS 93 vs. 42 weeks, unadjusted HR, 0.46; P = 0.0028). Adverse immune-related events were not increased by the combination treatment, and LPT-induced local toxicities were in most cases mild. In a multivariable Cox regression analysis, we show that the effect of added LPT on OS remained statistically significant after adjusting for BRAF status, tumor stage, tumor burden, and central nervous system metastases (adjusted HR, 0.56; 95% confidence interval, 0.31-1.01, P = 0.05). Our data suggest that the addition of LPT to ipilimumab is safe and effective in patients with metastatic melanoma irrespective of clinical disease characteristics and known risk factors. Induction of antitumor immune responses is most likely the underlying mechanism and warrants prospective validation. Cancer Immunol Res; 4(9); 744-54. ©2016 AACR.

Imatinib Triggers Phagolysosome Acidification and Antimicrobial Activity against Mycobacterium bovis Bacille Calmette-Guérin in Glucocorticoid-Treated Human Macrophages.

Glucocorticoids are extensively used to treat inflammatory diseases; however, their chronic intake increases the risk for mycobacterial infections. Meanwhile, the effects of glucocorticoids on innate host responses are incompletely understood. In this study, we investigated the direct effects of glucocorticoids on antimycobacterial host defense in primary human macrophages. We found that glucocorticoids triggered the expression of cathelicidin, an antimicrobial critical for antimycobacterial responses, independent of the intracellular vitamin D metabolism. Despite upregulating cathelicidin, glucocorticoids failed to promote macrophage antimycobacterial activity. Gene expression profiles of human macrophages treated with glucocorticoids and/or IFN-γ, which promotes induction of cathelicidin, as well as antimycobacterial activity, were investigated. Using weighted gene coexpression network analysis, we identified a module of highly connected genes that was strongly inversely correlated with glucocorticoid treatment and associated with IFN-γ stimulation. This module was linked to the biological functions autophagy, phagosome maturation, and lytic vacuole/lysosome, and contained the vacuolar H(+)-ATPase subunit a3, alias TCIRG1, a known antimycobacterial host defense gene, as a top hub gene. We next found that glucocorticoids, in contrast with IFN-γ, failed to trigger expression and phagolysosome recruitment of TCIRG1, as well as to promote lysosome acidification. Finally, we demonstrated that the tyrosine kinase inhibitor imatinib induces lysosome acidification and antimicrobial activity in glucocorticoid-treated macrophages without reversing the anti-inflammatory effects of glucocorticoids. Taken together, we provide evidence that the induction of cathelicidin by glucocorticoids is not sufficient for macrophage antimicrobial activity, and identify the vacuolar H(+)-ATPase as a potential target for host-directed therapy in the context of glucocorticoid therapy.

Vitamin D every day to keep the infection away?

Within the last decade, vitamin D has emerged as a central regulator of host defense against infections. In this regard, vitamin D triggers effective antimicrobial pathways against bacterial, fungal and viral pathogens in cells of the human innate immune system. However, vitamin D also mediates potent tolerogenic effects: it is generally believed that vitamin D attenuates inflammation and acquired immunity, and thus potentially limits collateral tissue damage. Nevertheless, several studies indicate that vitamin D promotes aspects of acquired host defense. Clinically, vitamin D deficiency has been associated with an increased risk for various infectious diseases in epidemiological studies; yet, robust data from controlled trials investigating the use of vitamin D as a preventive or therapeutic agent are missing. In this review, we summarize the current knowledge regarding the effect of vitamin D on innate and acquired host defense, and speculate on the difficulties to translate the available molecular medicine data into practical therapeutic or preventive recommendations.

Vitamin D regulates cytokine patterns secreted by dendritic cells to promote differentiation of IL-22-producing T cells.

One central mechanism, by which vitamin D regulates human immune responses, is the direct modulation of dendritic cells (DCs). However, the effect of vitamin D on several key DC functions, such as the secretion of central inflammatory cytokines, remains controversial. Moreover, whether vitamin D treatment of DCs regulates their ability to promote differentiation of IL-17-/IL-22-producing T cell subsets, such as Th17 and Th22 cell, is not known. Here, we report that vitamin D treatment during differentiation of monocytes into DCs markedly enhanced their ability to secrete TNF-α, IL-6, IL-1ß and IL-23. Cytokines secreted by vitamin D-treated DC were significantly more potent in driving differentiation of IL-22-producing T cells, but not IL-17-producing T cells, as compared to secreted cytokines of not-vitamin D-treated DCs. Finally, we found that the differentiation of IL-22-producing T cells mediated by supernatants of vitamin D-treated DCs was dependent on TNF-α IL-6 and IL-23. In summary, our study suggests a novel role of vitamin D in regulating DC-mediated immune responses in humans.

CD40 ligand and interferon-γ induce an antimicrobial response against Mycobacterium tuberculosis in human monocytes.

The ability of T cells to activate antimicrobial pathways in infected macrophages is essential to host defence against many intracellular pathogens. Here, we compared the ability of two T-cell-mediated mechanisms to trigger antimicrobial responses against Mycobacterium tuberculosis in humans, CD40 activation and the release of interferon-γ (IFN-γ). Given that IFN-γ activates a vitamin D-dependent antimicrobial response, we focused on induction of the key components of this pathway. We show that activation of human monocytes via CD40 ligand (CD40L) and IFN-γ, alone, and in combination, induces the CYP27b1-hydroxylase, responsible for the conversion of 25-hydroxyvitamin D (25D) to the bioactive 1,25-dihydroxyvitamin D (1,25D), and the vitamin D receptor (VDR). The activation of the vitamin D pathway by CD40L and IFN-γ results in up-regulated expression of the antimicrobial peptides, cathelicidin and DEFB4, as well as induction of autophagy. Finally, activation of monocytes via CD40L and IFN-γ results in an antimicrobial activity against intracellular M. tuberculosis. Our data suggest that at least two parallel T-cell-mediated mechanisms, CD40L and IFN-γ, activate the vitamin D-dependent antimicrobial pathway and trigger antimicrobial activity against intracellular M. tuberculosis, thereby contributing to human host defence against intracellular infection.

Sustained glutamate receptor activation down-regulates GABAB receptors by shifting the balance from recycling to lysosomal degradation.

Metabotropic GABA(B) receptors are abundantly expressed at glutamatergic synapses where they control excitability of the synapse. Here, we tested the hypothesis that glutamatergic neurotransmission may regulate GABA(B) receptors. We found that application of glutamate to cultured cortical neurons led to rapid down-regulation of GABA(B) receptors via lysosomal degradation. This effect was mimicked by selective activation of AMPA receptors and further accelerated by coactivation of group I metabotropic glutamate receptors. Inhibition of NMDA receptors, blockade of L-type Ca(2+) channels, and removal of extracellular Ca(2+) prevented glutamate-induced down-regulation of GABA(B) receptors, indicating that Ca(2+) influx plays a critical role. We further established that glutamate-induced down-regulation depends on the internalization of GABA(B) receptors. Glutamate did not affect the rate of GABA(B) receptor endocytosis but led to reduced recycling of the receptors back to the plasma membrane. Blockade of lysosomal activity rescued receptor recycling, indicating that glutamate redirects GABA(B) receptors from the recycling to the degradation pathway. In conclusion, the data indicate that sustained activation of AMPA receptors down-regulates GABA(B) receptors by sorting endocytosed GABA(B) receptors preferentially to lysosomes for degradation on the expense of recycling. This mechanism may relieve glutamatergic synapses from GABA(B) receptor-mediated inhibition resulting in increased synaptic excitability.

A member of the highly conserved FWL (tomato FW2.2-like) gene family is essential for soybean nodule organogenesis.

A soybean homolog of the tomato FW2.2 gene, here named GmFWL1 (Glycine max FW2.2-like 1), was found to respond strongly to inoculation with the nitrogen-fixing symbiotic bacterium Bradyrhizobium japonicum. In tomato, the FW2.2 gene is hypothesized to control 30% of the variance in fruit weight by negatively regulating cell division. In the present study, the induction of GmFWL1 expression in root hair cells and nodules in response to B. japonicum inoculation was documented using quantitative RT-PCR and transcriptional fusions to both beta-glucuronidase (GUS) and green fluorescent protein (GFP). RNAi-mediated silencing of GmFWL1 expression resulted in a significant reduction in nodule number, with a concomitant reduction in nuclear size and changes in chromatin structure. The reduction in nuclear size is probably due to a change in DNA heterochromatinization, as the ploidy level of wild-type and RNAi-silenced nodule cells was similar. GmFWL1 was localized to the plasma membrane. The data suggest that GmFWL1 probably acts indirectly, perhaps through a cellular cascade, to affect chromatin structure/nuclei architecture. As previously proposed in tomato, this function may be a result of effects on plant cell division.

Large-scale analysis of putative soybean regulatory gene expression identifies a Myb gene involved in soybean nodule development.

Nodulation is the result of a symbiosis between legumes and rhizobial bacteria in soil. This symbiosis is mutually beneficial, with the bacteria providing a source of nitrogen to the host while the plant supplies carbon to the symbiont. Nodule development is a complex process that is tightly regulated in the host plant cell through networks of gene expression. In order to examine this regulation in detail, a library of quantitative reverse transcription-polymerase chain reaction primer sets was developed for a large number of soybean (Glycine max) putative regulatory genes available in the current expressed sequence tag collection. This library contained primers specific to soybean transcription factor genes as well as genes involved in chromatin modification and translational regulation. Using this library, we analyzed the expression of this gene set during nodule development. A large number of genes were found to be differentially expressed, especially at the later stages of nodule development when active nitrogen fixation was occurring. Expression of these putative regulatory genes was also analyzed in response to the addition of nitrate as a nitrogen source. This comparative analysis identified genes that may be specifically involved in nitrogen assimilation, metabolism, and the maintenance of active nodules. To address this possibility, the expression of one such candidate was studied in more detail by expressing in soybean roots promoter beta-glucuronidase and green fluorescent protein fusions. This gene, named Control of Nodule Development (CND), encoded a Myb transcription factor gene. When the CND gene was silenced, nodulation was reduced. These results, associated with a strong expression of the CND gene in the vascular tissues, suggest a role for CND in controlling soybean nodulation.

Melorheostosis of the hand in a 7-year-old girl.

Melorheostosis of the hand is rare. We report a 7-year-old girl who presented with a contracture of the left hand. Diagnosis was made by conventional radiography and bone scintigraphy. MRI proved to be a very useful tool to visualize the soft-tissue changes. This is especially important when surgical repair is considered.