Cyclosporin A-treated Dendritic Cells may affect the outcome of organ transplantation by decreasing CD4+CD25+ regulatory T cell proliferation

http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602010000300010&lng=es&nrm=isoOne of the mechanisms for generation of tolerance involves immature dendritic cells (DCs) and a subpopulation of regulatory CD4+ CD25+ T lymphocytes (TREG). The purpose of this work was to analyze how Cyclosporine A (CsA), a widely used immunosuppressive drug, may affect TREG proliferation. Purified and activated murine DCs obtained from bone marrow precursors differentiated with rGMCSF were co-cultured with purified CFSE-labeled TREG from OTII mice, and their phenotype and proliferation analyzed by flow cytometry. Our data indicate that DCs differentiated in the presence of CsA show an altered phenotype, with a lower expression of MHC-II and a lower activating capacity. Additionally, these CsA-treated DCs show decreased production of IL-2 and IL-12 and increased IL-10 secretion when stimulated with LPS, indicating an effect on the polarization of the immune response. Interestingly, CsA-treated DCs show an anti-tolerogenic effect since they reduce the proliferation of TREG cells from 72 to 47%. Further inhibition to a 24% of TREG proliferation was obtained as a direct effect of CsA on TREG. In conclusion, the anti-tolerogenic effect of CsA should be considered in the planning of immunosuppression in the context of clinical transplantation

Towards autotrophic tissue engineering: Photosynthetic gene therapy for regeneration

Artículo científicoThe use of artificial tissues in regenerative medicine is limited due to hypoxia. As a strategy to overcome this drawback, we have shown that photosynthetic biomaterials can produce and provide oxygen independently of blood perfusion by generating chimeric animal-plant tissues during dermal regeneration. In this work, we demonstrate the safety and efficacy of photosynthetic biomaterials in vivo after engraftment in a fully immunocompetent mouse skin defect model. Further, we show that it is also possible to genetically engineer such photosynthetic scaffolds to deliver other key molecules in addition to oxygen. As a proof-of-concept, biomaterials were loaded with gene modified microalgae expressing the angiogenic recombinant protein VEGF. Survival of the algae, growth factor delivery and regenerative potential were evaluated in vitro and in vivo. This work proposes the use of photosynthetic gene therapy in regenerative medicine and provides scientific evidence for the use of engineered microalgae as an alternative to deliver recombinant molecules for gene therapy

Normal tissue homeostasis and impairment of selective inflammatory responses in dendritic cells deficient for ATF6α

The initiation of adaptive immunity relies on the performance of dendritic cells (DCs), which are specialized leukocytes with professional antigen presenting capabilities. As such, the molecular mechanisms safeguarding DC homeostasis are matter of intense research. Sensors of the unfolded protein response (UPR) of the endoplasmic reticulum, a three-pronged signaling pathway that maintains the fidelity of the cellular proteome, have emerged as regulators of DC biology. The archetypical example is the IRE1/XBP1s axis, which supports DC development and survival of the conventional type 1 DC (cDC1) subtype. However, the role of additional UPR sensors in DC biology, such as the ATF6α branch, has not been clearly elucidated. Even though Xbp1 is transcriptionally induced by ATF6α under ER stress, it is unclear if cDCs also co-opt the ATF6α branch in tissues. Here, we examine the role of ATF6α in cDC homeostasis in vivo and upon innate stimulation in vitro. In steady state, animals lacking ATF6α in CD11c+ cells (Itgax Cre x Atf6fl/fl mice) display normal cDC frequencies in spleen, intestine, liver, and lung. Also, ATF6α deficient cDCs express normal levels of Xbp1 mRNA and additional UPR components. However, a reduction of lung monocytes is observed in Itgax Cre x Atf6fl/fl conditional deficient animals suggesting that ATF6α may play a role in the biology of monocyte subsets. Notably, in settings of DC activation, ATF6α contributes to the production of IL-12 and IL-6 to inflammatory stimuli. Thus, although ATF6α may be dispensable for tissue cDC homeostasis in steady state, the transcription factor plays a role in the acquisition of selective immunogenic features by activated DCs

The Life Span Determinant p66Shc Localizes to Mitochondria Where It Associates with Mitochondrial Heat Shock Protein 70 and Regulates Trans-membrane Potential

P66Shc regulates life span in mammals and is a critical component of the apoptotic response to oxidative stress. It functions as a downstream target of the tumor suppressor p53 and is indispensable for the ability of oxidative stress-activated p53 to induce apoptosis. The molecular mechanisms underlying the apoptogenic effect of p66Shc are unknown. Here we report the following three findings. (i) The apoptosome can be properly activated in vitro in the absence of p66Shc only if purified cytochrome c is supplied. (ii) Cytochrome c release after oxidative signals is impaired in the absence of p66Shc. (iii) p66Shc induces the collapse of the mitochondrial trans-membrane potential after oxidative stress. Furthermore, we showed that a fraction of cytosolic p66Shc localizes within mitochondria where it forms a complex with mitochondrial Hsp70. Treatment of cells with ultraviolet radiation induced the dissociation of this complex and the release of monomeric p66Shc. We propose that p66Shc regulates the mitochondrial pathway of apoptosis by inducing mitochondrial damage after dissociation from an inhibitory protein complex. Genetic and biochemical evidence suggests that mitochondria regulate life span through their effects on the energetic metabolism (mitochondrial theory of aging). Our data suggest that mitochondrial regulation of apoptosis might also contribute to life span determination

Luces y sombras entre familias y escuelas : una relación protagónica en el escenario educativo actual

Fil: Ferreyra, Horacio Ademar. Universidad Católica de Córdoba. Facultad de Educación; ArgentinaFil: Bonetti, Olga Concepción. Universidad Católica de Córdoba. Facultad de Educación; ArgentinaFil: Di Francesco, Adriana Carlota. Universidad Católica de Córdoba. Facultad de Educación; Argentin

Luces y sombras entre familias y escuelas: una relación protagónica en el escenario educativo actual

Fil: Ferreyra, Horacio Ademar. Universidad Católica de Córdoba. Facultad de Educación; ArgentinaFil: Bonetti, Olga Concepción. Universidad Católica de Córdoba. Facultad de Educación; ArgentinaFil: Di Francesco, Adriana Carlota. Universidad Católica de Córdoba. Facultad de Educación; Argentin

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Functional consequences of immune cell adhesion to endothelial cells

Research regarding the interactions between the endothelium and immune cells has undergone a significant expansion during the past decade. Major shifts of emphasis have been the norm, from the production of a detail catalog of the cell surface receptors and counter-receptors acting at the interface between the vascular endothelium and circulating cells to a more mechanistic account of leukocyte / endothelium interactions. The past five years has seen new, groundbreaking developments in the field, with exiting studies aimed at understanding the functional consequences of the direct contact of endothelial cells and leukocytes. Based on early work to be discussed below, new data on local chemokine production and cell-to-cell contacts, attempt to clarify the physiopathological significance of these events. The exceptional anatomical arrangement of endothelial cells insures a permanent contact of the endothelium with leukocytes, an event likely to result in cellular signals originating from direct cell contact or through the action of soluble factors produced by endothelial cells or immune cells. As we will discuss, current evidence supports the idea that endothelial cells present at vascular endothelium as well as at specialized high endothelial venules, play not only a critical role in the homing and recruitment of immune cells but that it can also influence the outcome of the immune response. Additionally, new evidence clearly corroborates the idea that B and T lymphocytes as well as NK cells can modulate endothelial cell functionm, from the production of a detail catalog of the cell surface receptors and counter-receptors acting at the interface between the vascular endothelium and circulating cells to a more mechanistic account of leukocyte/endothelium interactions. The past five years has seen new, groundbreaking developments in the field, with exiting studies aimed at understanding the functional consequences of the direct contact of endothelial cells and leukocytes. Based on early work to be discussed below, new data on local chemokine production and cell-to-cell contacts, attempt to clarify the physiopathological significance of these events. The exceptional anatomical arrangement of endothelial cells insures a permanent contact of the endothelium with leukocytes, an event likely to result in cellular signals originating from direct cell contact or through the action of soluble factors produced by endothelial cells or immune cells. As we will discuss, current evidence supports the idea that endothelial cells present at vascular endothelium as well as at specialized high endothelial venules, play not only a critical role in the homing and recruitment of immune cells but that it can also influence the outcome of the immune response. Additionally, new evidence clearly corroborates the idea that B and T lymphocytes as well as NK cells can modulate endothelial cell functio

Blocking of human T lymphocyte activation by channel antagonists

It has been established that early events in lymphocyte activation involve a rise in intracellular Ca++ as well as changes in the flux of other ions. Although a Ca++ channel has been postulated to participate in the early Ca++ rise, its presence in lymphocytes remains controversial. Also although yet undetected, electrophysiological data suggest the presence of a Ca++ activated K+ channel on human peripheral blood lymphocytes (HPBL). Here we report on the effect of specific channel blockers as an approach to the identification of these channels on HPBL. At 40 nM nifedipine, an inhibitor of voltage‐gated Ca++ channels, fully inhibits the PHA‐promoted activation of HPBL. This effect is concentration dependant with a half maximum effect at approximately 10 nM and is demonstrable whether the drug is added at the same time as or up to 18 h after the addition of the mitogen. This inhibition of activation is not seen if the lymphocytes are activated using IL‐2 instead of PHA. Charybdotoxin