1,720,999 research outputs found
The role of the mitochondria and the endoplasmic reticulum contact sites in the development of the immune responses
Full text linkAbstractMitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are dynamic modules enriched in subset of lipids and specialized proteins that determine their structure and functions. The MERCs regulate lipid transfer, autophagosome formation, mitochondrial fission, Ca2+ homeostasis and apoptosis. Since these functions are essential for cell biology, it is therefore not surprising that MERCs also play a critical role in organ physiology among which the immune system stands by its critical host defense function. This defense system must discriminate and tolerate host cells and beneficial commensal microorganisms while eliminating pathogenic ones in order to preserve normal homeostasis. To meet this goal, the immune system has two lines of defense. First, the fast acting but unspecific innate immune system relies on anatomical physical barriers and subsets of hematopoietically derived cells expressing germline-encoded receptors called pattern recognition receptors (PRR) recognizing conserved motifs on the pathogens. Second, the slower but very specific adaptive immune response is added to complement innate immunity. Adaptive immunity relies on another set of specialized cells, the lymphocytes, harboring receptors requiring somatic recombination to be expressed. Both innate and adaptive immune cells must be activated to phagocytose and process pathogens, migrate, proliferate, release soluble factors and destroy infected cells. Some of these functions are strongly dependent on lipid transfer, autophagosome formation, mitochondrial fission, and Ca2+ flux; this indicates that MERCs could regulate immunity.</jats:p
Granzymes in health and diseases: the good, the bad and the ugly
Full text linkGranzymes are a family of serine proteases, composed of five human members: GA, B, H, M and K. They were first discovered in the 1980s within cytotoxic granules released during NK cell- and T cell-mediated killing. Through their various proteolytic activities, granzymes can trigger different pathways within cells, all of which ultimately lead to the same result, cell death. Over the years, the initial consideration of granzymes as mere cytotoxic mediators has changed due to surprising findings demonstrating their expression in cells other than immune effectors as well as new intracellular and extracellular activities. Additional roles have been identified in the extracellular milieu, following granzyme escape from the immunological synapse or their release by specific cell types. Outside the cell, granzyme activities mediate extracellular matrix alteration via the degradation of matrix proteins or surface receptors. In certain contexts, these processes are essential for tissue homeostasis; in others, excessive matrix degradation and extensive cell death contribute to the onset of chronic diseases, inflammation, and autoimmunity. Here, we provide an overview of both the physiological and pathological roles of granzymes, highlighting their utility while also recognizing how their unregulated presence can trigger the development and/or worsening of diseases
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Characterization of host substrate of SARS-CoV-2 NSP3 and NSP5 using a degradome approach
No full textreservedINTRODUCTION: The COVID-19 disease emerged in December 2019 and caused a global threat to the global population. The causative virus, SARS-CoV-2 belongs to the Coronaviridae virus family. The SARS-CoV-2, once attached, internalizes its virus particle into the cell. Then, the virus particle opens and releases its RNA genome. This viral RNA is directly translated into a single long polypeptide (pp1a and pp1ab) that must be proteolytically processed to produce the set of viral proteins among which non-structural protein NSP3 (papain like proteases) and NSP5 (main protease 3-chymotrypsin-like) are the only two viral proteases. These proteases are essential to the viral replication and life cycle. The immune system antiviral response depends on the recognition of viral components and the severity of the disease is directly related to both host and virus genetic makeup. Degradome analysis allows to characterize the function of proteases by the exhaustive identification of their substrates to determine the cellular pathways upon which the proteases exert control. OBJECTIVE: we aim at better evaluating the host cells and pathogens interaction during SARS-CoV-2 infection by characterizing NSP3 and NSP5 degradomes. This degradomic analysis will better our understand SARS-CoV-2 pathophysiology and to help in developing alternative treatments more efficient against genetic variants in a long term. METHODS: we develop an inducible expression system for NSP3 and NSP5 proteases. We generated doxycycline (Dox)-inducible THP1, a monocyte cell line, and A549, a type II pneumocyte line, to investigate NSP3 and NSP5 degradome respectively in immune and pneumocyte cells, which are relevant for the pathophysiology of COVID 19. RESULTS: cells were electroporated with pLVX-Tet3G encoding for the Tet-3G transcriptional activator and selected with antibiotic. Selected cells were cloned by limiting dilution. To evaluate the Dox inducibility of the clones, a sample of each clone was transduced with pLVX TRE3G Luc, encoding for the firefly luciferase reporter under the control of the Tet-3G responsive promoter, and selected with antibiotic. Then, Firefly luciferase activity was tested with by glow luciferase assay. For each cell line, 2 Dox-inducible clones were selected, one with a medium and the other with a higher inducibility. The 4 selected clones were transfected with pLVX TREG-NSP3 and pLVX TREG-NSP5 encoding for wild type or catalytically inactive mutant forms of the proteases, selected with antibiotic and protease expression tested by Western Blot analysis. Our preliminary data suggest that we could express NSP3 and NSP5 in our inducible cell expression system. In sequence the degradome characterization will be performed.INTRODUCTION: The COVID-19 disease emerged in December 2019 and caused a global threat to the global population. The causative virus, SARS-CoV-2 belongs to the Coronaviridae virus family. The SARS-CoV-2, once attached, internalizes its virus particle into the cell. Then, the virus particle opens and releases its RNA genome. This viral RNA is directly translated into a single long polypeptide (pp1a and pp1ab) that must be proteolytically processed to produce the set of viral proteins among which non-structural protein NSP3 (papain like proteases) and NSP5 (main protease 3-chymotrypsin-like) are the only two viral proteases. These proteases are essential to the viral replication and life cycle. The immune system antiviral response depends on the recognition of viral components and the severity of the disease is directly related to both host and virus genetic makeup. Degradome analysis allows to characterize the function of proteases by the exhaustive identification of their substrates to determine the cellular pathways upon which the proteases exert control. OBJECTIVE: we aim at better evaluating the host cells and pathogens interaction during SARS-CoV-2 infection by characterizing NSP3 and NSP5 degradomes. This degradomic analysis will better our understand SARS-CoV-2 pathophysiology and to help in developing alternative treatments more efficient against genetic variants in a long term. METHODS: we develop an inducible expression system for NSP3 and NSP5 proteases. We generated doxycycline (Dox)-inducible THP1, a monocyte cell line, and A549, a type II pneumocyte line, to investigate NSP3 and NSP5 degradome respectively in immune and pneumocyte cells, which are relevant for the pathophysiology of COVID 19. RESULTS: cells were electroporated with pLVX-Tet3G encoding for the Tet-3G transcriptional activator and selected with antibiotic. Selected cells were cloned by limiting dilution. To evaluate the Dox inducibility of the clones, a sample of each clone was transduced with pLVX TRE3G Luc, encoding for the firefly luciferase reporter under the control of the Tet-3G responsive promoter, and selected with antibiotic. Then, Firefly luciferase activity was tested with by glow luciferase assay. For each cell line, 2 Dox-inducible clones were selected, one with a medium and the other with a higher inducibility. The 4 selected clones were transfected with pLVX TREG-NSP3 and pLVX TREG-NSP5 encoding for wild type or catalytically inactive mutant forms of the proteases, selected with antibiotic and protease expression tested by Western Blot analysis. Our preliminary data suggest that we could express NSP3 and NSP5 in our inducible cell expression system. In sequence the degradome characterization will be performed
Characterization of the effect of T cell killing ability and resistance to environmental ROS on the efficiency of CAR-T cell Immunotherapy
No full textreservedChimeric Antigens Receptor (CAR) T cells adoptive transfer represents a revolutionary strategy in cancer treatment.
Indeed, anti-CD19 CAR T cells therapy has dramatically changed the fate of patients with relapsed/refractory
(r/r)diffuse large B-cell lymphoma (DLBCL) and related aggressive lymphomas with a reported 52-82% immediate
responses. However, only 40% of the patients with these hematologic malignancies achieve complete tumor
eradication and prolonged remission and sadly the effectiveness of CAR-T cell therapy against solid tumors is even
lower. Indeed, although anti-IL13Rα2-specific CAR- T cells represent a safe approach to treat (GBM), multiple
clinical trials have demonstrated that CAR-T cells monotherapy are not highly effective against these solid tumors.
Importantly, the escape mechanisms to this immunotherapy are driven by tumor cell complex structural variant
resulting from previous line of conventional treatments, alteration of mRNA-editing pathway, oxidative genomic
alteration, loss of tumor suppressor and only for asmall fraction the loss of the CD19 antigen in the case of lymphoma.
The immunosuppressive tumor microenvironment, the blood brain barrier and tumor heterogeneity account for the
inefficiency of CAR-T cell therapy against GBM. It is, therefore, highly likely that the capacity of cancer cell to
resist cell death favor the emergence of these variants. Moreover, cytotoxic lymphocytes kill their target in an
apoptosis-dependent manner meaning in a non-immunogenic cell death manner. Interestingly, in our laboratory we have
found that microenvironmental reactive oxygen species (ROS) strongly impact on the cytotoxic lymphocyte ability
to kill the cancer target cells. Suggesting that modulating the cytotoxic lymphocyte sensitivity to environmental
ROS could be an innovative strategy to improve CAR-T cell therapy. Therefore, the goal of my project is to characterize
the effect of T cell killing ability and resistance to environmental ROS on the efficiency of CAR-T cell Immunotherapy.
To achieve this goal, I will develop new generation of CAR-T cell with enhance killing capacity and resistance to
environmental ROS to improve CAR-T cell adoptive immunotherapy.Chimeric Antigens Receptor (CAR) T cells adoptive transfer represents a revolutionary strategy in cancer treatment.
Indeed, anti-CD19 CAR T cells therapy has dramatically changed the fate of patients with relapsed/refractory
(r/r)diffuse large B-cell lymphoma (DLBCL) and related aggressive lymphomas with a reported 52-82% immediate
responses. However, only 40% of the patients with these hematologic malignancies achieve complete tumor
eradication and prolonged remission and sadly the effectiveness of CAR-T cell therapy against solid tumors is even
lower. Indeed, although anti-IL13Rα2-specific CAR- T cells represent a safe approach to treat (GBM), multiple
clinical trials have demonstrated that CAR-T cells monotherapy are not highly effective against these solid tumors.
Importantly, the escape mechanisms to this immunotherapy are driven by tumor cell complex structural variant
resulting from previous line of conventional treatments, alteration of mRNA-editing pathway, oxidative genomic
alteration, loss of tumor suppressor and only for asmall fraction the loss of the CD19 antigen in the case of lymphoma.
The immunosuppressive tumor microenvironment, the blood brain barrier and tumor heterogeneity account for the
inefficiency of CAR-T cell therapy against GBM. It is, therefore, highly likely that the capacity of cancer cell to
resist cell death favor the emergence of these variants. Moreover, cytotoxic lymphocytes kill their target in an
apoptosis-dependent manner meaning in a non-immunogenic cell death manner. Interestingly, in our laboratory we have
found that microenvironmental reactive oxygen species (ROS) strongly impact on the cytotoxic lymphocyte ability
to kill the cancer target cells. Suggesting that modulating the cytotoxic lymphocyte sensitivity to environmental
ROS could be an innovative strategy to improve CAR-T cell therapy. Therefore, the goal of my project is to characterize
the effect of T cell killing ability and resistance to environmental ROS on the efficiency of CAR-T cell Immunotherapy.
To achieve this goal, I will develop new generation of CAR-T cell with enhance killing capacity and resistance to
environmental ROS to improve CAR-T cell adoptive immunotherapy
Mitochondria-ER Contact Sites in CD8+ T Cell: How Organellular Distance Varies Between the CD8+ T Cell Subsets.
No full textreservedINTRODUCTION: The immune system, which encompasses the innate and adaptive immune system, protects against pathogens, maintains tissue homeostasis and promotes wound healing. CD8+ T cells, a type of lymphocyte belonging to the adaptive immune system, participate in the elimination of intracellular pathogens and tumor cells, and the maintenance of immunologic memory. The differentiation of CD8+ T cells involves several stages, from naïve T cells, over various memory subsets up to effector cells, each defined by distinct phenotypic and metabolic characteristics, which support their activation, differentiation, and specific function. Mitochondria-endoplasmic reticulum contact sites have been identified as pivotal regulators of various cellular processes, including calcium and lipid transfer, mitochondrial dynamics, and apoptosis. MERCs are therefore likely to also play a key role in CD8+ T cell differentiation and function. OBJECTIVE: The objective of this project is to characterize the MERC status across the different subsets of CD8+ T cells. Ultimately, we hope that this work will help in the development of new therapies for disease states such as viral infections and cancer or autoimmune conditions that remain unresolved because of a dysfunctional CD8+ T cell response, by tailoring CD8+ cell differentiation based on the modulation of MERCs. METHODS: We isolated CD8+ T cells from peripheral blood mononuclear cells and sorted them into five subsets using fluorescence-activated cell sorting based on surface markers (CD45RA, CXCR3, CD95). A Fluorescence Resonance Energy Transfer (FRET)-based probe was employed, utilizing energy transfer between two fluorophores to map the proximity between mitochondria and ER in in the different CD8+ T cell subsets. Conditions were optimized for effective high-content screening imaging in CD8+ T cells. RESULTS: We successfully established and optimized a protocol for MERC analysis in human CD8+ T cells, based on FRET. The characterization of the MERC status in the CD8+ T cell subsets indicated varying levels of mitochondria-ER proximities, with naïve and stem cell memory T cells exhibiting the highest ER-mitochondria interaction, as indicated by the highest FRET ratios, whereas central and effector memory T cells had the lowest, and effector T cells showed intermediate levels of mitochondria-ER proximity. CONCLUSION: Our findings demonstrate that CD8+ T cells exhibit distinct levels of proximity at the MERCs during their differentiation process. The ability to manipulate MERCs may hold potential for developing therapies aimed at optimizing CD8+ T cell responses, thus improving treatments for chronic viral infections, cancer, and autoimmune disorders.INTRODUCTION: The immune system, which encompasses the innate and adaptive immune system, protects against pathogens, maintains tissue homeostasis and promotes wound healing. CD8+ T cells, a type of lymphocyte belonging to the adaptive immune system, participate in the elimination of intracellular pathogens and tumor cells, and the maintenance of immunologic memory. The differentiation of CD8+ T cells involves several stages, from naïve T cells, over various memory subsets up to effector cells, each defined by distinct phenotypic and metabolic characteristics, which support their activation, differentiation, and specific function. Mitochondria-endoplasmic reticulum contact sites have been identified as pivotal regulators of various cellular processes, including calcium and lipid transfer, mitochondrial dynamics, and apoptosis. MERCs are therefore likely to also play a key role in CD8+ T cell differentiation and function. OBJECTIVE: The objective of this project is to characterize the MERC status across the different subsets of CD8+ T cells. Ultimately, we hope that this work will help in the development of new therapies for disease states such as viral infections and cancer or autoimmune conditions that remain unresolved because of a dysfunctional CD8+ T cell response, by tailoring CD8+ cell differentiation based on the modulation of MERCs. METHODS: We isolated CD8+ T cells from peripheral blood mononuclear cells and sorted them into five subsets using fluorescence-activated cell sorting based on surface markers (CD45RA, CXCR3, CD95). A Fluorescence Resonance Energy Transfer (FRET)-based probe was employed, utilizing energy transfer between two fluorophores to map the proximity between mitochondria and ER in in the different CD8+ T cell subsets. Conditions were optimized for effective high-content screening imaging in CD8+ T cells. RESULTS: We successfully established and optimized a protocol for MERC analysis in human CD8+ T cells, based on FRET. The characterization of the MERC status in the CD8+ T cell subsets indicated varying levels of mitochondria-ER proximities, with naïve and stem cell memory T cells exhibiting the highest ER-mitochondria interaction, as indicated by the highest FRET ratios, whereas central and effector memory T cells had the lowest, and effector T cells showed intermediate levels of mitochondria-ER proximity. CONCLUSION: Our findings demonstrate that CD8+ T cells exhibit distinct levels of proximity at the MERCs during their differentiation process. The ability to manipulate MERCs may hold potential for developing therapies aimed at optimizing CD8+ T cell responses, thus improving treatments for chronic viral infections, cancer, and autoimmune disorders
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
