Tumor necrosis factor (TNF) ligand family members are synthesized as transmembrane proteins, and cleavage of the membrane-anchored proteins from the cell surface is frequently observed. The TNF-related ligands APRIL and BLyS and their cognate receptors BCMA/TACI form a two ligand/two receptor system that has been shown to participate in B-and T-cell stimulation. In contrast to BLyS, which is known to be cleaved from the cell surface, we found that APRIL is processed intracellularly by furin convertase. Blockage of protein transport from the endoplasmic reticulum to the Golgi apparatus by Brefeldin A treatment abrogated APRIL processing, whereas monensin, an inhibitor of post-Golgi transport, did not interfere with cleavage of APRIL, but blocked secretion of processed APRIL. Thus, APRIL shows a unique maturation pathway among the TNF ligand family members, as it not detectable as a membrane-anchored protein at the cell surface, but is processed in the Golgi apparatus prior to its secretion.
Summary Donation after circulatory death (DCD) has become an accepted practice in many countries and remains a focus of intense interest in the transplant community. The present study is aimed at providing a description of the current situation of DCD in European countries. Specific questionnaires were developed to compile information on DCD practices, activities and post‐transplant outcomes. Thirty‐five countries completed the survey. DCD is practiced in 18 countries: eight have both controlled DCD (cDCD) and uncontrolled DCD (uDCD) programs, 4 only cDCD and 6 only uDCD. All these countries have legally binding and/or nonbinding texts to regulate the practice of DCD. The no‐touch period ranges from 5 to 30 min. There are variations in ante and post mortem interventions used for the practice of cDCD. During 2008–2016, the highest DCD activity was described in the United Kingdom, Spain, Russia, the Netherlands, Belgium and France. Data on post‐transplant outcomes of patients who receive DCD donor kidneys show better results with grafts obtained from cDCD versus uDCD donors. In conclusion, DCD is becoming increasingly accepted and performed in Europe, importantly contributing to the number of organs available and providing acceptable post‐transplantation outcomes.
The TNF-like ligands APRIL and BLyS are close relatives and share the capacity to bind the receptors TACI and BCMA. BLyS has been shown to play an important role in B cell homeostasis and autoimmunity, but the biological role of APRIL remains less well defined. Analysis of T cells revealed an activation-dependent increase in APRIL mRNA expression. We therefore generated mice expressing APRIL as a transgene in T cells. These mice appeared normal and showed no signs of B cell hyperplasia. Transgenic T cells revealed a greatly enhanced survival in vitro as well as enhanced survival of staphylococcal enterotoxin B-reactive CD4 + T cells in vivo, which both directly correlate with elevated Bcl-2 levels. Analysis of humoral responses to T cell-dependent antigens in the transgenic mice indicated that APRIL affects only IgM but not IgG responses. In contrast, T cell-independent type 2 (TI-2) humoral response was enhanced in APRIL transgenic mice. As TACI was previously reported to be indispensable for TI-2 antibody formation, these results suggest a role for APRIL/TACI interactions in the generation of this response. Taken together, our data indicate that APRIL is involved in the induction and/or maintenance of T and B cell responses.
The TNF-like ligands APRIL and BLyS are close relatives and share the capacity to bind the receptors TACI and BCMA. BLyS has been shown to play an important role in B cell homeostasis and autoimmunity, but the biological role of APRIL remains less well defined. Analysis of T cells revealed an activation-dependent increase in APRIL mRNA expression. We therefore generated mice expressing APRIL as a transgene in T cells. These mice appeared normal and showed no signs of B cell hyperplasia. Transgenic T cells revealed a greatly enhanced survival in vitro as well as enhanced survival of staphylococcal enterotoxin B-reactive CD4 + T cells in vivo, which both directly correlate with elevated Bcl-2 levels. Analysis of humoral responses to T cell-dependent antigens in the transgenic mice indicated that APRIL affects only IgM but not IgG responses. In contrast, T cell-independent type 2 (TI-2) humoral response was enhanced in APRIL transgenic mice. As TACI was previously reported to be indispensable for TI-2 antibody formation, these results suggest a role for APRIL/TACI interactions in the generation of this response. Taken together, our data indicate that APRIL is involved in the induction and/or maintenance of T and B cell responses.
M cells assist mucosal immune surveillance by transcytosis of particles to underlying lymphoid tissue, but the mechanisms of M cell differentiation are poorly understood. To develop a better defined cell culture model of M cell differentiation, we treated human (Caco-2BBe) and rat (IEC-6) intestinal epithelial cell lines with lymphotoxin beta receptor (LTβR) and TNF receptor (TNFR) agonists. Treated cells were studied for regulation of genes associated with M cell and FollicleAssociated Epithelium (FAE). We found that LTβR and TNFR agonists induce transcription of FAE specific genes (Ccl20 and Lamb3) in Caco2-BBe cells and IEC-6 cells as well as rodent M cell specific genes such as Sgne-1/Scg5, Cldn4, and Gp2. The cytokines have distinct but complementary effects; TNFR agonists mainly induced FAE specific genes, while the LTβR agonist induced M cell specific genes. The combination of cytokines showed additive induction of the FAE-associated Ccl20, Lamb3 and a surprising induction of CD137/Tnfrsf9. On the other hand TNF agonists appeared to suppress expression of some LTβR-induced genes. Functionally, cytokine treatment led to the reorganization of microvilli and Claudin-4 redistribution. These studies suggest complex interactions between these cytokines in the context of either inflammation or tissue differentiation.
RNA interference is an endogenous mechanism present in most eukaryotic cells that enables degradation of specific mRNAs. Pharmacological exploitation of this mechanism for therapeutic purposes attracted a whole amount of attention in its initial years, but was later hampered due to difficulties in delivery of the pharmacological agents to the appropriate organ or tissue. Advances in recent years have to a certain level started to address this specific issue. Genetic diseases are caused by aberrations in gene sequences or structure; these particular abnormalities are in theory easily addressable by RNAi therapeutics. Sequencing of the human genome has largely contributed to the identification of alterations responsible for genetic conditions, thus facilitating the design of compounds that can address these diseases. This review addresses the currently on-going programs with the aim of developing RNAi and other antisense compounds for the treatment of genetic conditions and the pros and cons that these products may encounter along the way. The authors have focused on those programs that have reached clinical trials or are very close to do so.
States are encouraged to include provisions on extraterritorial jurisdiction in their laws on transplant-related crimes and to collaborate with professionals and international authorities in the development of a global registry of transnational transplant activities. These actions would assist in the identification and evaluation of illicit activities and provide information that would help in developing strategies to deter and prevent them.
For many years, there has been an ongoing search for new compounds that can selectively alter gene expression as a new way to treat human disease by addressing targets that are otherwise "undruggable" with traditional pharmaceutical approaches involving small molecules or proteins. RNA interference (RNAi) strategies have raised a lot of attention and several compounds are currently being tested in clinical trials. Viruses are the obvious target for RNAi-therapy, as most are difficult to treat with conventional drugs, they become rapidly resistant to drug treatment and their genes differ substantially from human genes, minimizing side effects. Antisense strategy offers very high target specificity, i.e., any viral sequence could potentially be targeted using the complementary oligonucleotide sequence. Consequently, new antisense-based therapeutics have the potential to lead a revolution in the anti-infective drug development field. Additionally, the relatively short turnaround for efficacy testing of potential RNAi molecules and that any pathogen is theoretically amenable to rapid targeting, make them invaluable tools for treating a wide range of diseases. This review will focus on some of the current efforts to treat infectious disease with RNAi-based therapies and some of the obstacles that have appeared on the road to successful clinical intervention.
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