Publications by category
Journal articles
Salazar F, Brown GD (In Press). A friendly danger. Science, 362, 292-293.
Jiménez JM, Salazar M, Arancibia S, Villar J, Salazar F, Brown GD, Lavelle EC, Martínez-Pomares L, Ortiz-Quintero J, Lavandero S, et al (In Press). TLR4, but Neither Dectin-1 nor Dectin-2, Participates in the Mollusk Hemocyanin-Induced Proinflammatory Effects in Antigen-Presenting Cells from Mammals.
Frontiers in Immunology,
10Abstract:
TLR4, but Neither Dectin-1 nor Dectin-2, Participates in the Mollusk Hemocyanin-Induced Proinflammatory Effects in Antigen-Presenting Cells from Mammals
Mollusk hemocyanins have biomedical uses as carriers/adjuvants and nonspecific immunostimulants with beneficial clinical outcomes by triggering the production of proinflammatory cytokines in antigen-presenting cells (APCs) and driving immune responses toward type 1 T helper (Th1) polarization. Significant structural features of hemocyanins as a model antigen are their glycosylation patterns. Indeed, hemocyanins have a multivalent nature as highly mannosylated antigens. We have previously shown that hemocyanins are internalized by APCs through receptor-mediated endocytosis with proteins that contain C-type lectin domains, such as mannose receptor (MR). However, the contribution of other innate immune receptors to the proinflammatory signaling pathway triggered by hemocyanins is unknown. Thus, we studied the roles of Dectin-1, Dectin-2, and Toll-like receptor 4 (TLR4) in the hemocyanin activation of murine APCs, both in dendritic cells (DCs) and macrophages, using hemocyanins from Megathura crenulata (KLH), Concholepas concholepas (CCH) and Fissurella latimarginata (FLH). The results showed that these hemocyanins bound to chimeric Dectin-1 and Dectin-2 receptors in vitro; which significantly decreased when the glycoproteins were deglycosylated. However, hemocyanin-induced proinflammatory effects in APCs from Dectin-1 knock-out (KO) and Dectin-2 KO mice were independent of both receptors. Moreover, when wild-type APCs were cultured in the presence of hemocyanins, phosphorylation of Syk kinase was not detected. We further showed that KLH and FLH induced ERK1/2 phosphorylation, a key event involved in the TLR signaling pathway. We confirmed a glycan-dependent binding of hemocyanins to chimeric TLR4 in vitro. Moreover, DCs from mice deficient for MyD88-adapter-like (Mal), a downstream adapter molecule of TLR4, were partially activated by FLH, suggesting a role of the TLR pathway in hemocyanin recognition to activate APCs. The participation of TLR4 was confirmed through a decrease in IL-12p40 and IL-6 secretion induced by FLH when a TLR4 blocking antibody was used; a reduction was also observed in DCs from C3H/HeJ mice, a mouse strain with a nonfunctional mutation for this receptor. Moreover, IL-6 secretion induced by FLH was abolished in macrophages deficient for TLR4. Our data showed the involvement of TLR4 in the hemocyanin-mediated proinflammatory response in APCs, which could cooperate with MR in innate immune recognition of these glycoproteins.
Abstract.
Hatinguais R, Kay M, Salazar F, Conn DP, Williams DL, Cook PC, Willment JA, Brown GD (2023). Development of Negative Controls for Fc-C-Type Lectin Receptor Probes.
Microbiol SpectrAbstract:
Development of Negative Controls for Fc-C-Type Lectin Receptor Probes.
Fc-C-type lectin receptor (Fc-CTLRs) probes are soluble chimeric proteins constituted of the extracellular domain of a CTLR fused with the constant fraction (Fc) of the human IgG. These probes are useful tools to study the interaction of CTLRs with their ligands, with applications similar to those of antibodies, often in combination with widely available fluorescent antibodies targeting the Fc fragment (anti-hFc). In particular, Fc-Dectin-1 has been extensively used to study the accessibility of β-glucans at the surface of pathogenic fungi. However, there is no universal negative control for Fc-CTLRs, making the distinction of specific versus nonspecific binding difficult. We describe here 2 negative controls for Fc-CTLRs: a Fc-control constituting of only the Fc portion, and a Fc-Dectin-1 mutant predicted to be unable to bind β-glucans. Using these new probes, we found that while Fc-CTLRs exhibit virtually no nonspecific binding to Candida albicans yeasts, Aspergillus fumigatus resting spores strongly bind Fc-CTLRs in a nonspecific manner. Nevertheless, using the controls we describe here, we were able to demonstrate that A. fumigatus spores expose a low amount of β-glucan. Our data highlight the necessity of appropriate negative controls for experiments involving Fc-CTLRs probes. IMPORTANCE While Fc-CTLRs probes are useful tools to study the interaction of CTLRs with ligands, their use is limited by the lack of appropriate negative controls in assays involving fungi and potentially other pathogens. We have developed and characterized 2 negative controls for Fc-CTLRs assays: Fc-control and a Fc-Dectin-1 mutant. In this manuscript, we characterize the use of these negative controls with zymosan, a β-glucan containing particle, and 2 human pathogenic fungi, Candida albicans yeasts and Aspergillus fumigatus conidia. We show that A. fumigatus conidia nonspecifically bind Fc-CTLRs probes, demonstrating the need for appropriate negative controls in such assays.
Abstract.
Author URL.
Dambuza IM, Warris A, Salazar F (2023). Unmasking a fungal fire.
PLOS Pathogens,
19(5), e1011355-e1011355.
Abstract:
Unmasking a fungal fire
Immune checkpoint inhibitor (ICI) therapy represents a breakthrough cancer treatment by stimulating dysfunctional T cells in the tumour environment to kill cancer cells. Beyond effects on anticancer immunity, ICI therapy may be associated with increased susceptibility to or more rapid resolution of chronic infections, particularly those caused by human fungal pathogens. In this concise review, we summarise recent observations and findings that implicate immune checkpoint blockade in fungal infection outcomes.
Abstract.
Salazar F, Bignell E, Brown GD, Cook PC, Warris A (2022). Pathogenesis of Respiratory Viral and Fungal Coinfections.
Clin Microbiol Rev,
35(1).
Abstract:
Pathogenesis of Respiratory Viral and Fungal Coinfections.
Individuals suffering from severe viral respiratory tract infections have recently emerged as "at risk" groups for developing invasive fungal infections. Influenza virus is one of the most common causes of acute lower respiratory tract infections worldwide. Fungal infections complicating influenza pneumonia are associated with increased disease severity and mortality, with invasive pulmonary aspergillosis being the most common manifestation. Strikingly, similar observations have been made during the current coronavirus disease 2019 (COVID-19) pandemic. The copathogenesis of respiratory viral and fungal coinfections is complex and involves a dynamic interplay between the host immune defenses and the virulence of the microbes involved that often results in failure to return to homeostasis. In this review, we discuss the main mechanisms underlying susceptibility to invasive fungal disease following respiratory viral infections. A comprehensive understanding of these interactions will aid the development of therapeutic modalities against newly identified targets to prevent and treat these emerging coinfections.
Abstract.
Author URL.
Villar J, Salazar ML, Jiménez JM, Campo MD, Manubens A, Gleisner MA, Ávalos I, Salazar-Onfray F, Salazar F, Mitchell DA, et al (2021). C-type lectin receptors MR and DC-SIGN are involved in recognition of hemocyanins, shaping their immunostimulatory effects on human dendritic cells.
Eur J Immunol,
51(7), 1715-1731.
Abstract:
C-type lectin receptors MR and DC-SIGN are involved in recognition of hemocyanins, shaping their immunostimulatory effects on human dendritic cells.
Hemocyanins are used as immunomodulators in clinical applications because they induce a strong Th1-biased cell-mediated immunity, which has beneficial effects. They are multiligand glycosylated molecules with abundant and complex mannose-rich structures. It remains unclear whether these structures influence hemocyanin-induced immunostimulatory processes in human APCs. We have previously shown that hemocyanin glycans from Concholepas concholepas (CCH), Fissurella latimarginata (FLH), and Megathura crenulata (KLH), participate in their immune recognition and immunogenicity in mice, interacting with murine C-type lectin receptors (CLRs). Here, we studied the interactions of these hemocyanins with two major mannose-binding CLRs on monocyte-derived human DCs: MR (mannose receptor) and DC-SIGN (DC-specific ICAM-3-grabbing nonintegrin). Diverse analyses showed that hemocyanins are internalized by a mannose-sensitive mechanism. This process was calcium dependent. Moreover, hemocyanins colocalized with MR and DC-SIGN, and were partly internalized through clathrin-mediated endocytosis. The hemocyanin-mediated proinflammatory cytokine response was impaired when using deglycosylated FLH and KLH compared to CCH. We further showed that hemocyanins bind to human MR and DC-SIGN in a carbohydrate-dependent manner with affinity constants in the physiological concentration range. Overall, we showed that these three clinically valuable hemocyanins interact with human mannose-sensitive CLRs, initiating an immune response and promoting a Th1 cell-driving potential.
Abstract.
Author URL.
Speakman EA, Dambuza IM, Salazar F, Brown GD (2020). T Cell Antifungal Immunity and the Role of C-Type Lectin Receptors.
Trends Immunol,
41(1), 61-76.
Abstract:
T Cell Antifungal Immunity and the Role of C-Type Lectin Receptors.
Fungi can cause disease in humans, from mucocutaneous to life-threatening systemic infections. Initiation of antifungal immunity involves fungal recognition by pattern recognition receptors such as C-type lectin receptors (CLRs). These germline-encoded receptors trigger a multitude of innate responses including phagocytosis, fungal killing, and antigen presentation which can also shape the development of adaptive immunity. Recently, studies have shed light on how CLRs directly or indirectly modulate lymphocyte function. Moreover, CLR-mediated recognition of commensal fungi maintains homeostasis and prevents invasion from opportunistic commensals. We present an overview of current knowledge of antifungal T cell immune responses, with emphasis on the role of C-type lectins, and discuss how these receptors modulate these responses at different levels.
Abstract.
Author URL.
Awuah D, Alobaid M, Latif A, Salazar F, Emes RD, Ghaemmaghami AM (2019). The Cross-Talk between miR-511-3p and C-Type Lectin Receptors on Dendritic Cells Affects Dendritic Cell Function.
The Journal of Immunology,
203(1), 148-157.
Abstract:
The Cross-Talk between miR-511-3p and C-Type Lectin Receptors on Dendritic Cells Affects Dendritic Cell Function
Abstract
. MicroRNAs are small, noncoding RNAs that function as posttranscriptional modulators of gene expression by binding target mRNAs and inhibiting translation. They are therefore crucial regulators of several biological as well as immunological events. Recently, miR-511-3p has been implicated in the development and differentiation of APCs, such as dendritic cells (DCs), and regulating several human diseases. Interestingly, miR-511-3p is embedded within the human MRC1 gene that encodes the mannose receptor. In this study, we sought to examine the impact of miR-511-3p up- or downregulation on human DC surface phenotype, cytokine profile, immunogenicity (using IDO activity as a surrogate), and downstream T cell polarization. Using gene silencing and a selection of microRNA mimics, we could successfully suppress or induce the expression of miR-511-3p in DCs. Consequently, we show for the first time, to our knowledge, that inhibition and/or overexpression of miR-511-3p has opposing effects on the expression levels of two key C-type lectin receptors, namely the mannose receptor and DC-specific ICAM 3 nonintegrin at protein and mRNA levels, thereby affecting C-type lectin receptor–induced modulation of IDO activity in DCs. Furthermore, we show that downregulation of miR-511-3p drives an anti-inflammatory DC response characterized by IL-10 production. Interestingly, the miR-511-3plow DCs also promoted IL-4 secretion and suppressed IL-17 in cocultures with autologous T cells. Together, our data highlight the potential role of miR-511 in regulating DC function and downstream events leading to Th polarization and immune modulation.
Abstract.
Salazar F, Brown GD (2018). Antifungal innate immunity: a perspective from last 10 years.
Journal of Innate Immunity,
10, 373-397.
Abstract:
Antifungal innate immunity: a perspective from last 10 years
Fungal pathogens can rarely cause disease in immunocompetent individuals. However, commensal and normally non-pathogenic environmental fungi can cause life threatening infections in immunocompromised individuals. Over the last few decades, there has been a huge increase in the incidence of invasive opportunistic fungal infections along with a worrying increase in antifungal drug resistance. As a consequence, research focused on understanding the molecular and cellular basis of antifungal immunity has expanded tremendously in the last few years. This review will provide an overview of the most exciting recent advances in innate antifungal immunity, discoveries that are helping to pave the way for the development of new strategies that are desperately needed to combat these devastating diseases.
Abstract.
Riabov V, Salazar F, Htwe SS, Gudima A, Schmuttermaier C, Barthes J, Knopf-Marques H, Klüter H, Ghaemmaghami AM, Vrana NE, et al (2017). Generation of anti-inflammatory macrophages for implants and regenerative medicine using self-standing release systems with a phenotype-fixing cytokine cocktail formulation. Acta Biomaterialia, 53, 389-398.
Salazar F, Awuah D, Negm OH, Shakib F, Ghaemmaghami AM (2017). The role of indoleamine 2,3-dioxygenase-aryl hydrocarbon receptor pathway in the TLR4-induced tolerogenic phenotype in human DCs.
Scientific Reports,
7(1).
Abstract:
The role of indoleamine 2,3-dioxygenase-aryl hydrocarbon receptor pathway in the TLR4-induced tolerogenic phenotype in human DCs
AbstractA controlled inflammatory response is required for protection against infection, but persistent inflammation causes tissue damage. Dendritic cells (DCs) have a unique capacity to promote both inflammatory and anti-inflammatory processes. One key mechanism involved in DC-mediated immunosuppression is the expression of tryptophan-metabolizing enzyme indoleamine 2,3-dioxygenase (IDO). IDO has been implicated in diverse processes in health and disease but its role in endotoxin tolerance in human DCs is still controversial. Here we investigated the role of IDO in shaping DCs phenotype and function under endotoxin tolerance conditions. Our data show that TLR4 ligation in LPS-primed DCs, induced higher levels of both IDO isoforms together with the transcription factor aryl-hydrocarbon receptor (AhR), compared to unprimed controls. Additionally, LPS conditioning induced an anti-inflammatory phenotype in DCs - with an increase in IL-10 and higher expression of programmed death ligand (PD-L)1 and PD-L2 - which were partially dependent on IDO. Furthermore, we demonstrated that the AhR-IDO pathway was responsible for the preferential activation of non-canonical NF-κB pathway in LPS-conditioned DCs. These data provide new insight into the mechanisms of the TLR4-induced tolerogenic phenotype in human DCs, which can help the better understanding of processes involved in induction and resolution of chronic inflammation and tolerance.
Abstract.
Aldajani WA, Salazar F, Sewell HF, Knox A, Ghaemmaghami AM (2016). Expression and regulation of immune-modulatory enzyme indoleamine 2,3-dioxygenase (IDO) by human airway epithelial cells and its effect on T cell activation. Oncotarget, 7(36), 57606-57617.
Rostam HM, Singh S, Salazar F, Magennis P, Hook A, Singh T, Vrana NE, Alexander MR, Ghaemmaghami AM (2016). The impact of surface chemistry modification on macrophage polarisation. Immunobiology, 221(11), 1237-1246.
Salazar F, Hall L, Negm OH, Awuah D, Tighe PJ, Shakib F, Ghaemmaghami AM (2016). The mannose receptor negatively modulates the Toll-like receptor 4–aryl hydrocarbon receptor–indoleamine 2,3-dioxygenase axis in dendritic cells affecting T helper cell polarization. Journal of Allergy and Clinical Immunology, 137(6), 1841-1851.e2.
Ebensperger LA, León C, Ramírez-Estrada J, Abades S, Hayes LD, Nova E, Salazar F, Bhattacharjee J, Becker MI (2015). Immunocompetence of breeding females is sensitive to cortisol levels but not to communal rearing in the degu (Octodon degus). Physiology & Behavior, 140, 61-70.
Arancibia S, Espinoza C, Salazar F, Del Campo M, Tampe R, Zhong T-Y, De Ioannes P, Moltedo B, Ferreira J, Lavelle EC, et al (2014). A Novel Immunomodulatory Hemocyanin from the Limpet Fissurella latimarginata Promotes Potent Anti-Tumor Activity in Melanoma. PLoS ONE, 9(1), e87240-e87240.
Harrington H, Cato P, Salazar F, Wilkinson M, Knox A, Haycock JW, Rose F, Aylott JW, Ghaemmaghami AM (2014). Immunocompetent 3D Model of Human Upper Airway for Disease Modeling and in Vitro Drug Evaluation. Molecular Pharmaceutics, 11(7), 2082-2091.
Salazar F, Ghaemmaghami AM (2013). Allergen Recognition by Innate Immune Cells: Critical Role of Dendritic and Epithelial Cells. Frontiers in Immunology, 4
Salazar F, Sewell HF, Shakib F, Ghaemmaghami AM (2013). The role of lectins in allergic sensitization and allergic disease. Journal of Allergy and Clinical Immunology, 132(1), 27-36.
Arancibia S, Campo MD, Nova E, Salazar F, Becker MI (2012). Enhanced structural stability of Concholepas hemocyanin increases its immunogenicity and maintains its non-specific immunostimulatory effects. European Journal of Immunology, 42(3), 688-699.
Del Campo M, Arancibia S, Nova E, Salazar F, González A, Moltedo B, De Ioannes P, Ferreira J, Manubens A, Becker MI, et al (2011). [Hemocyanins as immunostimulants].
Rev Med Chil,
139(2), 236-246.
Abstract:
[Hemocyanins as immunostimulants].
Hemocyanins, the giant oxygen transporter glycoproteins of diverse mollusks, are xenogenic to the mammalian immune system and they display a remarkable immuno-genicity. Therefore they are ideal non-specific immunostimulants to treat some types of cancer. They are used as an alternative therapy for superficial urinary bladder cancer (SBC), that has been traditionally treated with Bacillus Calmette-Guerin (BCG). In contrast to BCG, hemocyanins do not cause side-effects, making them ideal for long-term repetitive treatments. Hemocyanins have also been exploited as carriers to develop antibodies against hapten molecules and peptides, as carrier-adjuvants for cutting-edge vaccines against cancer, drug addiction, and infectious diseases and in the diagnosis of parasitic diseases, such as Schistosomiasis. The hemocyanin from Megathura crenulata, also known as keyhole limpet hemocyanin (KLH), has been used for over thirty years for the purposes described above. More recently, hemoc yanin from the Chilean mollusk Concholepas concholepas (CCH) has proved to be a reliable alternative to KLH, either as carrier protein, and as a likely alternative for the immunotherapy of SBC. Despite KLH and CCH differ significantly in their origin and structure, we have demonstrated that both hemocyanins stimulate the immune system of mammals in a similar way by inducing a potent Thl-polarized cellular and humoral response.
Abstract.
Author URL.
Manubens A, Salazar F, Haussmann D, Figueroa J, Del Campo M, Pinto JM, Huaquín L, Venegas A, Becker MI (2010). Concholepas hemocyanin biosynthesis takes place in the hepatopancreas, with hemocytes being involved in its metabolism. Cell and Tissue Research, 342(3), 423-435.
Chapters
Arancibia S, Salazar F, Ins M (2012). Hemocyanins in the Immunotherapy of Superficial Bladder Cancer. In (Ed) Bladder Cancer - from Basic Science to Robotic Surgery, InTech.
Publications by year
In Press
Salazar F, Brown GD (In Press). A friendly danger. Science, 362, 292-293.
Jiménez JM, Salazar M, Arancibia S, Villar J, Salazar F, Brown GD, Lavelle EC, Martínez-Pomares L, Ortiz-Quintero J, Lavandero S, et al (In Press). TLR4, but Neither Dectin-1 nor Dectin-2, Participates in the Mollusk Hemocyanin-Induced Proinflammatory Effects in Antigen-Presenting Cells from Mammals.
Frontiers in Immunology,
10Abstract:
TLR4, but Neither Dectin-1 nor Dectin-2, Participates in the Mollusk Hemocyanin-Induced Proinflammatory Effects in Antigen-Presenting Cells from Mammals
Mollusk hemocyanins have biomedical uses as carriers/adjuvants and nonspecific immunostimulants with beneficial clinical outcomes by triggering the production of proinflammatory cytokines in antigen-presenting cells (APCs) and driving immune responses toward type 1 T helper (Th1) polarization. Significant structural features of hemocyanins as a model antigen are their glycosylation patterns. Indeed, hemocyanins have a multivalent nature as highly mannosylated antigens. We have previously shown that hemocyanins are internalized by APCs through receptor-mediated endocytosis with proteins that contain C-type lectin domains, such as mannose receptor (MR). However, the contribution of other innate immune receptors to the proinflammatory signaling pathway triggered by hemocyanins is unknown. Thus, we studied the roles of Dectin-1, Dectin-2, and Toll-like receptor 4 (TLR4) in the hemocyanin activation of murine APCs, both in dendritic cells (DCs) and macrophages, using hemocyanins from Megathura crenulata (KLH), Concholepas concholepas (CCH) and Fissurella latimarginata (FLH). The results showed that these hemocyanins bound to chimeric Dectin-1 and Dectin-2 receptors in vitro; which significantly decreased when the glycoproteins were deglycosylated. However, hemocyanin-induced proinflammatory effects in APCs from Dectin-1 knock-out (KO) and Dectin-2 KO mice were independent of both receptors. Moreover, when wild-type APCs were cultured in the presence of hemocyanins, phosphorylation of Syk kinase was not detected. We further showed that KLH and FLH induced ERK1/2 phosphorylation, a key event involved in the TLR signaling pathway. We confirmed a glycan-dependent binding of hemocyanins to chimeric TLR4 in vitro. Moreover, DCs from mice deficient for MyD88-adapter-like (Mal), a downstream adapter molecule of TLR4, were partially activated by FLH, suggesting a role of the TLR pathway in hemocyanin recognition to activate APCs. The participation of TLR4 was confirmed through a decrease in IL-12p40 and IL-6 secretion induced by FLH when a TLR4 blocking antibody was used; a reduction was also observed in DCs from C3H/HeJ mice, a mouse strain with a nonfunctional mutation for this receptor. Moreover, IL-6 secretion induced by FLH was abolished in macrophages deficient for TLR4. Our data showed the involvement of TLR4 in the hemocyanin-mediated proinflammatory response in APCs, which could cooperate with MR in innate immune recognition of these glycoproteins.
Abstract.
2023
Hatinguais R, Kay M, Salazar F, Conn DP, Williams DL, Cook PC, Willment JA, Brown GD (2023). Development of Negative Controls for Fc-C-Type Lectin Receptor Probes.
Microbiol SpectrAbstract:
Development of Negative Controls for Fc-C-Type Lectin Receptor Probes.
Fc-C-type lectin receptor (Fc-CTLRs) probes are soluble chimeric proteins constituted of the extracellular domain of a CTLR fused with the constant fraction (Fc) of the human IgG. These probes are useful tools to study the interaction of CTLRs with their ligands, with applications similar to those of antibodies, often in combination with widely available fluorescent antibodies targeting the Fc fragment (anti-hFc). In particular, Fc-Dectin-1 has been extensively used to study the accessibility of β-glucans at the surface of pathogenic fungi. However, there is no universal negative control for Fc-CTLRs, making the distinction of specific versus nonspecific binding difficult. We describe here 2 negative controls for Fc-CTLRs: a Fc-control constituting of only the Fc portion, and a Fc-Dectin-1 mutant predicted to be unable to bind β-glucans. Using these new probes, we found that while Fc-CTLRs exhibit virtually no nonspecific binding to Candida albicans yeasts, Aspergillus fumigatus resting spores strongly bind Fc-CTLRs in a nonspecific manner. Nevertheless, using the controls we describe here, we were able to demonstrate that A. fumigatus spores expose a low amount of β-glucan. Our data highlight the necessity of appropriate negative controls for experiments involving Fc-CTLRs probes. IMPORTANCE While Fc-CTLRs probes are useful tools to study the interaction of CTLRs with ligands, their use is limited by the lack of appropriate negative controls in assays involving fungi and potentially other pathogens. We have developed and characterized 2 negative controls for Fc-CTLRs assays: Fc-control and a Fc-Dectin-1 mutant. In this manuscript, we characterize the use of these negative controls with zymosan, a β-glucan containing particle, and 2 human pathogenic fungi, Candida albicans yeasts and Aspergillus fumigatus conidia. We show that A. fumigatus conidia nonspecifically bind Fc-CTLRs probes, demonstrating the need for appropriate negative controls in such assays.
Abstract.
Author URL.
Dambuza IM, Warris A, Salazar F (2023). Unmasking a fungal fire.
PLOS Pathogens,
19(5), e1011355-e1011355.
Abstract:
Unmasking a fungal fire
Immune checkpoint inhibitor (ICI) therapy represents a breakthrough cancer treatment by stimulating dysfunctional T cells in the tumour environment to kill cancer cells. Beyond effects on anticancer immunity, ICI therapy may be associated with increased susceptibility to or more rapid resolution of chronic infections, particularly those caused by human fungal pathogens. In this concise review, we summarise recent observations and findings that implicate immune checkpoint blockade in fungal infection outcomes.
Abstract.
2022
Salazar F, Bignell E, Brown GD, Cook PC, Warris A (2022). Pathogenesis of Respiratory Viral and Fungal Coinfections.
Clin Microbiol Rev,
35(1).
Abstract:
Pathogenesis of Respiratory Viral and Fungal Coinfections.
Individuals suffering from severe viral respiratory tract infections have recently emerged as "at risk" groups for developing invasive fungal infections. Influenza virus is one of the most common causes of acute lower respiratory tract infections worldwide. Fungal infections complicating influenza pneumonia are associated with increased disease severity and mortality, with invasive pulmonary aspergillosis being the most common manifestation. Strikingly, similar observations have been made during the current coronavirus disease 2019 (COVID-19) pandemic. The copathogenesis of respiratory viral and fungal coinfections is complex and involves a dynamic interplay between the host immune defenses and the virulence of the microbes involved that often results in failure to return to homeostasis. In this review, we discuss the main mechanisms underlying susceptibility to invasive fungal disease following respiratory viral infections. A comprehensive understanding of these interactions will aid the development of therapeutic modalities against newly identified targets to prevent and treat these emerging coinfections.
Abstract.
Author URL.
2021
Villar J, Salazar ML, Jiménez JM, Campo MD, Manubens A, Gleisner MA, Ávalos I, Salazar-Onfray F, Salazar F, Mitchell DA, et al (2021). C-type lectin receptors MR and DC-SIGN are involved in recognition of hemocyanins, shaping their immunostimulatory effects on human dendritic cells.
Eur J Immunol,
51(7), 1715-1731.
Abstract:
C-type lectin receptors MR and DC-SIGN are involved in recognition of hemocyanins, shaping their immunostimulatory effects on human dendritic cells.
Hemocyanins are used as immunomodulators in clinical applications because they induce a strong Th1-biased cell-mediated immunity, which has beneficial effects. They are multiligand glycosylated molecules with abundant and complex mannose-rich structures. It remains unclear whether these structures influence hemocyanin-induced immunostimulatory processes in human APCs. We have previously shown that hemocyanin glycans from Concholepas concholepas (CCH), Fissurella latimarginata (FLH), and Megathura crenulata (KLH), participate in their immune recognition and immunogenicity in mice, interacting with murine C-type lectin receptors (CLRs). Here, we studied the interactions of these hemocyanins with two major mannose-binding CLRs on monocyte-derived human DCs: MR (mannose receptor) and DC-SIGN (DC-specific ICAM-3-grabbing nonintegrin). Diverse analyses showed that hemocyanins are internalized by a mannose-sensitive mechanism. This process was calcium dependent. Moreover, hemocyanins colocalized with MR and DC-SIGN, and were partly internalized through clathrin-mediated endocytosis. The hemocyanin-mediated proinflammatory cytokine response was impaired when using deglycosylated FLH and KLH compared to CCH. We further showed that hemocyanins bind to human MR and DC-SIGN in a carbohydrate-dependent manner with affinity constants in the physiological concentration range. Overall, we showed that these three clinically valuable hemocyanins interact with human mannose-sensitive CLRs, initiating an immune response and promoting a Th1 cell-driving potential.
Abstract.
Author URL.
2020
Speakman EA, Dambuza IM, Salazar F, Brown GD (2020). T Cell Antifungal Immunity and the Role of C-Type Lectin Receptors.
Trends Immunol,
41(1), 61-76.
Abstract:
T Cell Antifungal Immunity and the Role of C-Type Lectin Receptors.
Fungi can cause disease in humans, from mucocutaneous to life-threatening systemic infections. Initiation of antifungal immunity involves fungal recognition by pattern recognition receptors such as C-type lectin receptors (CLRs). These germline-encoded receptors trigger a multitude of innate responses including phagocytosis, fungal killing, and antigen presentation which can also shape the development of adaptive immunity. Recently, studies have shed light on how CLRs directly or indirectly modulate lymphocyte function. Moreover, CLR-mediated recognition of commensal fungi maintains homeostasis and prevents invasion from opportunistic commensals. We present an overview of current knowledge of antifungal T cell immune responses, with emphasis on the role of C-type lectins, and discuss how these receptors modulate these responses at different levels.
Abstract.
Author URL.
2019
Awuah D, Alobaid M, Latif A, Salazar F, Emes RD, Ghaemmaghami AM (2019). The Cross-Talk between miR-511-3p and C-Type Lectin Receptors on Dendritic Cells Affects Dendritic Cell Function.
The Journal of Immunology,
203(1), 148-157.
Abstract:
The Cross-Talk between miR-511-3p and C-Type Lectin Receptors on Dendritic Cells Affects Dendritic Cell Function
Abstract
. MicroRNAs are small, noncoding RNAs that function as posttranscriptional modulators of gene expression by binding target mRNAs and inhibiting translation. They are therefore crucial regulators of several biological as well as immunological events. Recently, miR-511-3p has been implicated in the development and differentiation of APCs, such as dendritic cells (DCs), and regulating several human diseases. Interestingly, miR-511-3p is embedded within the human MRC1 gene that encodes the mannose receptor. In this study, we sought to examine the impact of miR-511-3p up- or downregulation on human DC surface phenotype, cytokine profile, immunogenicity (using IDO activity as a surrogate), and downstream T cell polarization. Using gene silencing and a selection of microRNA mimics, we could successfully suppress or induce the expression of miR-511-3p in DCs. Consequently, we show for the first time, to our knowledge, that inhibition and/or overexpression of miR-511-3p has opposing effects on the expression levels of two key C-type lectin receptors, namely the mannose receptor and DC-specific ICAM 3 nonintegrin at protein and mRNA levels, thereby affecting C-type lectin receptor–induced modulation of IDO activity in DCs. Furthermore, we show that downregulation of miR-511-3p drives an anti-inflammatory DC response characterized by IL-10 production. Interestingly, the miR-511-3plow DCs also promoted IL-4 secretion and suppressed IL-17 in cocultures with autologous T cells. Together, our data highlight the potential role of miR-511 in regulating DC function and downstream events leading to Th polarization and immune modulation.
Abstract.
2018
Salazar F, Brown GD (2018). Antifungal innate immunity: a perspective from last 10 years.
Journal of Innate Immunity,
10, 373-397.
Abstract:
Antifungal innate immunity: a perspective from last 10 years
Fungal pathogens can rarely cause disease in immunocompetent individuals. However, commensal and normally non-pathogenic environmental fungi can cause life threatening infections in immunocompromised individuals. Over the last few decades, there has been a huge increase in the incidence of invasive opportunistic fungal infections along with a worrying increase in antifungal drug resistance. As a consequence, research focused on understanding the molecular and cellular basis of antifungal immunity has expanded tremendously in the last few years. This review will provide an overview of the most exciting recent advances in innate antifungal immunity, discoveries that are helping to pave the way for the development of new strategies that are desperately needed to combat these devastating diseases.
Abstract.
2017
Riabov V, Salazar F, Htwe SS, Gudima A, Schmuttermaier C, Barthes J, Knopf-Marques H, Klüter H, Ghaemmaghami AM, Vrana NE, et al (2017). Generation of anti-inflammatory macrophages for implants and regenerative medicine using self-standing release systems with a phenotype-fixing cytokine cocktail formulation. Acta Biomaterialia, 53, 389-398.
Salazar F, Awuah D, Negm OH, Shakib F, Ghaemmaghami AM (2017). The role of indoleamine 2,3-dioxygenase-aryl hydrocarbon receptor pathway in the TLR4-induced tolerogenic phenotype in human DCs.
Scientific Reports,
7(1).
Abstract:
The role of indoleamine 2,3-dioxygenase-aryl hydrocarbon receptor pathway in the TLR4-induced tolerogenic phenotype in human DCs
AbstractA controlled inflammatory response is required for protection against infection, but persistent inflammation causes tissue damage. Dendritic cells (DCs) have a unique capacity to promote both inflammatory and anti-inflammatory processes. One key mechanism involved in DC-mediated immunosuppression is the expression of tryptophan-metabolizing enzyme indoleamine 2,3-dioxygenase (IDO). IDO has been implicated in diverse processes in health and disease but its role in endotoxin tolerance in human DCs is still controversial. Here we investigated the role of IDO in shaping DCs phenotype and function under endotoxin tolerance conditions. Our data show that TLR4 ligation in LPS-primed DCs, induced higher levels of both IDO isoforms together with the transcription factor aryl-hydrocarbon receptor (AhR), compared to unprimed controls. Additionally, LPS conditioning induced an anti-inflammatory phenotype in DCs - with an increase in IL-10 and higher expression of programmed death ligand (PD-L)1 and PD-L2 - which were partially dependent on IDO. Furthermore, we demonstrated that the AhR-IDO pathway was responsible for the preferential activation of non-canonical NF-κB pathway in LPS-conditioned DCs. These data provide new insight into the mechanisms of the TLR4-induced tolerogenic phenotype in human DCs, which can help the better understanding of processes involved in induction and resolution of chronic inflammation and tolerance.
Abstract.
2016
Aldajani WA, Salazar F, Sewell HF, Knox A, Ghaemmaghami AM (2016). Expression and regulation of immune-modulatory enzyme indoleamine 2,3-dioxygenase (IDO) by human airway epithelial cells and its effect on T cell activation. Oncotarget, 7(36), 57606-57617.
Rostam HM, Singh S, Salazar F, Magennis P, Hook A, Singh T, Vrana NE, Alexander MR, Ghaemmaghami AM (2016). The impact of surface chemistry modification on macrophage polarisation. Immunobiology, 221(11), 1237-1246.
Salazar F, Hall L, Negm OH, Awuah D, Tighe PJ, Shakib F, Ghaemmaghami AM (2016). The mannose receptor negatively modulates the Toll-like receptor 4–aryl hydrocarbon receptor–indoleamine 2,3-dioxygenase axis in dendritic cells affecting T helper cell polarization. Journal of Allergy and Clinical Immunology, 137(6), 1841-1851.e2.
2015
Ebensperger LA, León C, Ramírez-Estrada J, Abades S, Hayes LD, Nova E, Salazar F, Bhattacharjee J, Becker MI (2015). Immunocompetence of breeding females is sensitive to cortisol levels but not to communal rearing in the degu (Octodon degus). Physiology & Behavior, 140, 61-70.
2014
Arancibia S, Espinoza C, Salazar F, Del Campo M, Tampe R, Zhong T-Y, De Ioannes P, Moltedo B, Ferreira J, Lavelle EC, et al (2014). A Novel Immunomodulatory Hemocyanin from the Limpet Fissurella latimarginata Promotes Potent Anti-Tumor Activity in Melanoma. PLoS ONE, 9(1), e87240-e87240.
Harrington H, Cato P, Salazar F, Wilkinson M, Knox A, Haycock JW, Rose F, Aylott JW, Ghaemmaghami AM (2014). Immunocompetent 3D Model of Human Upper Airway for Disease Modeling and in Vitro Drug Evaluation. Molecular Pharmaceutics, 11(7), 2082-2091.
2013
Salazar F, Ghaemmaghami AM (2013). Allergen Recognition by Innate Immune Cells: Critical Role of Dendritic and Epithelial Cells. Frontiers in Immunology, 4
Salazar F, Sewell HF, Shakib F, Ghaemmaghami AM (2013). The role of lectins in allergic sensitization and allergic disease. Journal of Allergy and Clinical Immunology, 132(1), 27-36.
2012
Arancibia S, Campo MD, Nova E, Salazar F, Becker MI (2012). Enhanced structural stability of Concholepas hemocyanin increases its immunogenicity and maintains its non-specific immunostimulatory effects. European Journal of Immunology, 42(3), 688-699.
Arancibia S, Salazar F, Ins M (2012). Hemocyanins in the Immunotherapy of Superficial Bladder Cancer. In (Ed) Bladder Cancer - from Basic Science to Robotic Surgery, InTech.
2011
Del Campo M, Arancibia S, Nova E, Salazar F, González A, Moltedo B, De Ioannes P, Ferreira J, Manubens A, Becker MI, et al (2011). [Hemocyanins as immunostimulants].
Rev Med Chil,
139(2), 236-246.
Abstract:
[Hemocyanins as immunostimulants].
Hemocyanins, the giant oxygen transporter glycoproteins of diverse mollusks, are xenogenic to the mammalian immune system and they display a remarkable immuno-genicity. Therefore they are ideal non-specific immunostimulants to treat some types of cancer. They are used as an alternative therapy for superficial urinary bladder cancer (SBC), that has been traditionally treated with Bacillus Calmette-Guerin (BCG). In contrast to BCG, hemocyanins do not cause side-effects, making them ideal for long-term repetitive treatments. Hemocyanins have also been exploited as carriers to develop antibodies against hapten molecules and peptides, as carrier-adjuvants for cutting-edge vaccines against cancer, drug addiction, and infectious diseases and in the diagnosis of parasitic diseases, such as Schistosomiasis. The hemocyanin from Megathura crenulata, also known as keyhole limpet hemocyanin (KLH), has been used for over thirty years for the purposes described above. More recently, hemoc yanin from the Chilean mollusk Concholepas concholepas (CCH) has proved to be a reliable alternative to KLH, either as carrier protein, and as a likely alternative for the immunotherapy of SBC. Despite KLH and CCH differ significantly in their origin and structure, we have demonstrated that both hemocyanins stimulate the immune system of mammals in a similar way by inducing a potent Thl-polarized cellular and humoral response.
Abstract.
Author URL.
2010
Manubens A, Salazar F, Haussmann D, Figueroa J, Del Campo M, Pinto JM, Huaquín L, Venegas A, Becker MI (2010). Concholepas hemocyanin biosynthesis takes place in the hepatopancreas, with hemocytes being involved in its metabolism. Cell and Tissue Research, 342(3), 423-435.