Retroviral Danger from Within: TLR7 Is in Control

In this issue of Immunity, Yu et al. (2012) outline a fascinating model in which TLR7-mediated antibody production acts as a dominant immunosurveillance mechanism against endogenous retroviruses (ERVs), with additional support of TLR3 and TLR9 that function to prevent ERV-mediated malignancy

Mechanisms of immune modulation in the tumor microenvironment and implications for targeted therapy

Cancer; Immunosuppression mechanisms; Tumor microenvironmentCáncer; Mecanismos de inmunosupresión; Microambiente tumoralCàncer; Mecanismes d'immunosupressió; Microambient tumoralThe efficacy of cancer therapies is limited to a great extent by immunosuppressive mechanisms within the tumor microenvironment (TME). Numerous immune escape mechanisms have been identified. These include not only processes associated with tumor, immune or stromal cells, but also humoral, metabolic, genetic and epigenetic factors within the TME. The identification of immune escape mechanisms has enabled the development of small molecules, nanomedicines, immune checkpoint inhibitors, adoptive cell and epigenetic therapies that can reprogram the TME and shift the host immune response towards promoting an antitumor effect. These approaches have translated into series of breakthroughs in cancer therapies, some of which have already been implemented in clinical practice. In the present article the authors provide an overview of some of the most important mechanisms of immunosuppression within the TME and the implications for targeted therapies against different cancers

Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses

<p>Abstract</p> <p>Background</p> <p>Hereditary Hemochromatosis (HH) is a genetic disease associated with iron overload, in which individuals homozygous for the mutant C282Y <it>HFE </it>associated allele are at risk for the development of a range of disorders particularly liver disease. Conformational diseases are a class of disorders associated with the expression of misfolded protein. HFE C282Y is a mutant protein that does not fold correctly and consequently is retained in the Endoplasmic Reticulum (ER). In this context, we sought to identify ER stress signals associated with mutant C282Y HFE protein expression, which may have a role in the molecular pathogenesis of HH.</p> <p>Results</p> <p>Vector constructs of Wild type HFE and Mutant C282Y HFE were made and transfected into HEK293 cell lines. We have shown that expression of C282Y HFE protein triggers both an unfolded protein response (UPR), as revealed by the increased GRP78, ATF6 and CHOP expression, and an ER overload response (EOR), as indicated by NF-κB activation. Furthermore, C282Y HFE protein induced apoptotic responses associated with activation of ER stress. Inhibition studies demonstrated that tauroursodeoxycholic acid, an endogenous bile acid, downregulates these events. Finally, we found that the co-existence of both C282Y HFE and Z alpha 1-antitrypsin protein (the protein associated with the liver disease of Z alpha 1-antitrypsin deficiency) expression on ER stress responses acted as potential disease modifiers with respect to each other.</p> <p>Conclusion</p> <p>Our novel observations suggest that both the ER overload response (EOR) and the unfolded protein response (UPR) are activated by mutant C282Y HFE protein.</p

TNF-α–dependent loss of IKKβ-deficient myeloid progenitors triggers a cytokine loop culminating in granulocytosis

Loss of IκB kinase (IKK) β-dependent NF-κB signaling in hematopoietic cells is associated with increased granulopoiesis. Here we identify a regulatory cytokine loop that causes neutrophilia in Ikkβ−deficient mice. TNF-α–dependent apoptosis of myeloid progenitor cells leads to the release of IL-1β, which promotes Th17 polarization of peripheral CD4+ T cells. Although the elevation of IL-17 and the consecutive induction of granulocyte colony-stimulating factor compensate for the loss of myeloid progenitor cells, the facilitated induction of Th17 cells renders Ikkβ-deficient animals more susceptible to the development of experimental autoimmune encephalitis. These results unravel so far unanticipated direct and indirect functions for IKKβ in myeloid progenitor survival and maintenance of innate and Th17 immunity and raise concerns about long-term IKKβ inhibition in IL-17–mediated diseases

Intracellular DNA sensing by neutrophils and amplification of the innate immune response.

Peer reviewed: TrueAs the first responders, neutrophils lead the innate immune response to infectious pathogens and inflammation inducing agents. The well-established pathogen neutralizing strategies employed by neutrophils are phagocytosis, the action of microbicide granules, the production of ROS, and the secretion of neutrophil extracellular traps (NETs). Only recently, the ability of neutrophils to sense and respond to pathogen-associated molecular patterns is being appreciated. This review brings together the current information about the intracellular recognition of DNA by neutrophils and proposes models of signal amplification in immune response. Finally, the clinical relevance of DNA sensing by neutrophils in infectious and non-infectious diseases including malignancy are also discussed

Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses-3

<p><b>Copyright information:</b></p><p>Taken from "Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses"</p><p>http://www.biomedcentral.com/1471-2121/8/30</p><p>BMC Cell Biology 2007;8():30-30.</p><p>Published online 24 Jul 2007</p><p>PMCID:PMC1947972.</p><p></p> luciferase reporter gene vector (ATF6-luc) (B) CHOP-promoter luciferase reporter gene vector (CHOP-luc), with or without pZeoSv2(data not shown). As positive control or treatment, five hours post transfection cells were incubated with 2.5 μM thapsigargin or 300 μM TUDCA for 24 h. Cells were incubated for 24 h in serum-complete medium. Luciferase production in cell lysates was measured by luminometry. Levels are expressed as light units (LU) per microgram of total protein. C282Y HFE activated ATF-6 and CHOP-luc expression (**, p = 0.0039 and **, p = 0.0011 respectively) compared to WT HFE. Treatment with TUDCA significantly decreased ATF6-luc and CHOP-luc expression (#, p = 0.0175 and ##, p = 0.0067 respectively) compared to WT HFE. Z A1AT transfection significantly increased ATF6-luc and CHOP-luc expression (*, p = 0.02 and **, p = 0.0059) compared to WT HFE. Assays were performed in triplicate and are representative of at least three separate experiments

Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses-5

<p><b>Copyright information:</b></p><p>Taken from "Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses"</p><p>http://www.biomedcentral.com/1471-2121/8/30</p><p>BMC Cell Biology 2007;8():30-30.</p><p>Published online 24 Jul 2007</p><p>PMCID:PMC1947972.</p><p></p>ciferase reporter gene vector. As positive control, five hours post transfection cells were stimulated with 2.5 μM thapsigargin for 24 h. Cells were incubated for 24 h in serum-complete medium. Luciferase production in cell lysates was measured by luminometry. Levels are expressed as light units (LU) per microgram of total protein. C282Y HFE decreased -luc expression (**, = 0.004) compared to WT HFE. Treatment with TUDCA significantly increased -luc expression (#, = 0.0238) compared to WT HFE. Z A1AT transfection significantly decreased -luc expression **, = 0.0029 compared to WT HFE transfected with M A1AT. Assays were performed in triplicate and are representative of at least three separate experiments. () HEK293 cells (1 × 10) were transfected with C282Y HFE (M) with or without Z A1AT expression plasmids. Transfected cells were untreated or treated with 300 μM TUDCA, and cytosolic extracts were prepared 24 h posttransfection. () Ten-microgram of protein was assayed for cytochrome release, and () caspase-3 activation by western blotting (= 3). Incubation with TUDCA markedly inhibited cytochrome release and processing of procaspse-3. () Blots were stripped and probed with β-Actin to confirm equal loading. () Measurement of caspase-3 activity in the lysates of HEK293 cells (1 × 10) transfected with C282Y HFE (M) and either Z A1AT HFE or M A1AT expression plasmids. Transfected cells were untreated or treated with 300 μM TUDCA. Positive control of 2.5 μM thapsigargin used. Z A1AT increased C282Y HFE (M) caspase-3 activity compared to M A1AT (*, = 0.0379) and treatment with 300 μM TUDCA significantly decreased C282Y HFE (M) induced caspase-3 activity compared to untreated (#, = 0.0214)

Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses-2

<p><b>Copyright information:</b></p><p>Taken from "Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses"</p><p>http://www.biomedcentral.com/1471-2121/8/30</p><p>BMC Cell Biology 2007;8():30-30.</p><p>Published online 24 Jul 2007</p><p>PMCID:PMC1947972.</p><p></p>r luciferase reporter gene vector (-luc) with or without pZeoSv2(data not shown), pMA1AT, or pZA1AT. As positive control or treatment, five hours post transfection cells were incubated with 2.5 μM thapsigargin or 300 μM TUDCA acid for 24 h. Cells were incubated for 24 h in serum-complete medium. Luciferase production in cell lysates was measured by luminometry. Levels are expressed as light units (LU) per microgram of total protein. C282Y HFE activated -luc expression (**, p = 0.0011) compared to WT HFE. Treatment with TUDCA significantly decreased grp78-LUC expression (##, p = 0.0006) compared to WT HFE. Z A1AT transfection significantly increased grp78-LUC expression (*, p = 0.016) compared to N HFE. Assays were performed in triplicate and are representative of at least three separate experiments. (B) GRP78/BIP protein production was analyzed by western blot in cytosolic extracts (10 μg) from HEK293 cells transfected with pcDNA3.1 (lane 1), WT HFE (lane 2), C282Y HFE (lane 3) or HEK293 cells stimulated with 2.5 μM thapsigargin (lane 4; n = 3). (C) GRP78/BIP protein production were analyzed by western blot in cytosolic extracts (10 μg) from HEK293 cells transfected with C282Y HFE untreated (lane 1) treated with 200 μM TUDCA (lane 2) 300 μM TUDCA (lane 3). (D) GRP78/BIP protein production were analyzed by western blot in cytosolic extracts (10 μg) from HEK293 cells transfected with pZA1AT with pcDNA3.1 (lane 1), WT HFE (lane 2) or C282Y HFE (lane 3) or HEK293 cells stimulated with 2.5 μM thapsigargin (lane 4; n = 3). Blots were stripped and probed for β-Actin to confirm equal loading

Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses-4

<p><b>Copyright information:</b></p><p>Taken from "Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses"</p><p>http://www.biomedcentral.com/1471-2121/8/30</p><p>BMC Cell Biology 2007;8():30-30.</p><p>Published online 24 Jul 2007</p><p>PMCID:PMC1947972.</p><p></p>apsigargin, and cytosolic extracts were prepared 24 h posttransfection. Ten-microgram of protein was assayed for cytochrome release (A), and caspase-3 activation (B) by western blotting (n = 3). C282Y HFE (M) induced cytochrome release and processing of procaspase-3 compared to EV, WT HFE or 2.5 μM thapsigargin treated cells. (C) To confirm equal loading blots were stripped and probed for β-Actin. (D) Measurement of caspase-3 activity in the lysates of HEK293 cells (1 × 10) transfected with control (empty vector), WT HFE or C282Y HFE expression vectors, and positive control of 2.5 μM thapsigargin was used. C282Y HFE significantly increased caspase-3 activity (*, p = 0.0363) (n = 3)