Role of protein kinase R in the killing of Leishmania major by macrophages in response to neutrophil elastase and TLR4 via TNF and IFN

In cutaneous leishmaniasis, Leishmania amazonensis activates macrophage double-stranded, RNA-activated protein kinase R (PKR) to promote parasite growth. In our study, Leishmania major grew normally in RAW cells, RAW-expressing dominant-negative PKR (PKR-DN) cells, and macrophages of PKR-knockout mice, revealing that PKR is dispensable for L. major growth in macrophages. PKR activation in infected macrophages with poly I:C resulted in parasite death. Fifty percent of L. major-knockout lines for the ecotin-like serine peptidase inhibitor (ISP2; Δisp2/isp3), an inhibitor of neutrophil elastase (NE), died in RAW cells or macrophages from 129Sv mice, as a result of PKR activation. Inhibition of PKR or NE or neutralization of Toll-like receptor 4 or 2(TLR4 or TLR2) prevented the death of Δisp2/isp3. Δisp2/isp3 grew normally in RAW-PKR-DN cells or macrophages from 129Sv pkr−/−, tlr2−/−, trif−/−, and myd88−/− mice, associating NE activity, PKR, and TLR responses with parasite death. Δisp2/isp3 increased the expression of mRNA for TNF-α by 2-fold and of interferon β (IFNβ) in a PKR-dependent manner. Antibodies to TNF-α reversed the 95% killing by Δisp2/isp3, whereas they grew normally in macrophages from IFN receptor–knockout mice. We propose that ISP2 prevents the activation of PKR via an NE-TLR4-TLR2 axis to control innate responses that contribute to the killing of L. major.—Faria, M. S., Calegari-Silva, T. C., de Carvalho Vivarini, A., Mottram, J. C., Lopes, U. G., Lima, A. P. C. A. Role of protein kinase R in the killing of Leishmania major by macrophages in response to neutrophil elastase and TLR4 via TNFα and IFNβ

The Utility of Capsicum annuum L. in Internal Medicine and In Dentistry: A Comprehensive Review

Capsaicin is a chili peppers extract, genus Capsicum, commonly used as a food spice. Since ancient times, Capsaicin has been used as a "homeopathic remedy" for treating a wild range of pathological conditions but without any scientific knowledge about its action. Several studies have demonstrated its potentiality in cardiovascular, nephrological, nutritional, and other medical fields. Capsaicin exerts its actions thanks to the bond with transient receptor potential vanilloid subtype 1 (TRPV1). TRPV1 is a nociceptive receptor, and its activation starts with a neurosensitive impulse, responsible for a burning pain sensation. However, constant local application of Capsaicin desensitized neuronal cells and leads to relief from neuropathic pain. In this review, we analyze the potential adjuvant role of Capsaicin in the treatment of different pathological conditions either in internal medicine or dentistry. Moreover, we present our experience in five patients affected by oro-facial pain consequent to post-traumatic trigeminal neuropathy, not responsive to any remedy, and successfully treated with topical application of Capsaicin. The topical application of Capsaicin is safe, effective, and quite tolerated by patients. For these reasons, in addition to the already-proven beneficial actions in the internal field, it represents a promising method for the treatment of neuropathic oral diseases

Lutzomyia longipalpis Saliva Induces Heme Oxygenase-1 Expression at Bite Sites

Sand flies bite mammalian hosts to obtain a blood meal, driving changes in the host inflammatory response that support the establishment of Leishmania infection. This effect is partially attributed to components of sand fly saliva, which are able to recruit and activate leukocytes. Our group has shown that heme oxygenase-1 (HO-1) favors Leishmania survival in infected cells by reducing inflammatory responses. Here, we show that exposure to sand fly bites is associated with induction of HO-1 in vivo. Histopathological analyses of skin specimens from human volunteers experimentally exposed to sand fly bites revealed that HO-1 and Nrf2 are produced at bite sites in the skin. These results were recapitulated in mice ears injected with a salivary gland sonicate (SGS) or exposed to sand fly bites, indicating that vector saliva may be a key factor in triggering HO-1 expression. Resident skin macrophages were the main source HO-1 at 24–48 h after bites. Additionally, assays in vivo after bites and in vitro after stimulation with saliva both demonstrated that HO-1 production by macrophages was Nrf2-dependent. Collectively, our data demonstrates that vector saliva induces early HO-1 production at the bite sites, representing a major event associated with establishment of naturally-transmitted Leishmania infections

Glycoinositolphospholipids from Leishmania braziliensis and L. infantum: Modulation of Innate Immune System and Variations in Carbohydrate Structure

The essential role of the lipophosphoglycan (LPG) of Leishmania in innate immune response has been extensively reported. However, information about the role of the LPG-related glycoinositolphospholipids (GIPLs) is limited, especially with respect to the New World species of Leishmania. GIPLs are low molecular weight molecules covering the parasite surface and are similar to LPG in sharing a common lipid backbone and a glycan motif containing up to 7 sugars. Critical aspects of their structure and functions are still obscure in the interaction with the vertebrate host. In this study, we evaluated the role of those molecules in two medically important South American species Leishmania infantum and L. braziliensis, causative agents of visceral (VL) and cutaneous Leishmaniasis (CL), respectively. GIPLs derived from both species did not induce NO or TNF-α production by non-primed murine macrophages. Additionally, primed macrophages from mice (BALB/c, C57BL/6, TLR2−/− and TLR4−/−) exposed to GIPLs from both species, with exception to TNF-α, did not produce any of the cytokines analyzed (IL1-β, IL-2, IL-4, IL-5, IL-10, IL-12p40, IFN-γ) or p38 activation. GIPLs induced the production of TNF-α and NO by C57BL/6 mice, primarily via TLR4. Pre incubation of macrophages with GIPLs reduced significantly the amount of NO and IL-12 in the presence of IFN-γ or lipopolysaccharide (LPS), which was more pronounced with L. braziliensis GIPLs. This inhibition was reversed after PI-specific phospholipase C treatment. A structural analysis of the GIPLs showed that L. infantum has manose rich GIPLs, suggestive of type I and Hybrid GIPLs while L. braziliensis has galactose rich GIPLs, suggestive of Type II GIPLs. In conclusion, there are major differences in the structure and composition of GIPLs from L. braziliensis and L. infantum. Also, GIPLs are important inhibitory molecules during the interaction with macrophages

Tissue and host species-specific transcriptional changes in models of experimental visceral leishmaniasis [version 2; referees : 4 approved]

Background: Human visceral leishmaniasis, caused by infection with Leishmania donovani or L. infantum, is a potentially fatal disease affecting 50,000-90,000 people yearly in 75 disease endemic countries, with more than 20,000 deaths reported. Experimental models of infection play a major role in understanding parasite biology, host-pathogen interaction, disease pathogenesis, and parasite transmission. In addition, they have an essential role in the identification and pre-clinical evaluation of new drugs and vaccines. However, our understanding of these models remains fragmentary. Although the immune response to Leishmania donovani infection in mice has been extensively characterized, transcriptomic analysis capturing the tissue-specific evolution of disease has yet to be reported. Methods: We provide an analysis of the transcriptome of spleen, liver and peripheral blood of BALB/c mice infected with L. donovani. Where possible, we compare our data in murine experimental visceral leishmaniasis with transcriptomic data in the public domain obtained from the study of L. donovani-infected hamsters and patients with human visceral leishmaniasis. Digitised whole slide images showing the histopathology in spleen and liver are made available via a dedicated website, www.leishpathnet.org. Results: Our analysis confirms marked tissue-specific alterations in the transcriptome of infected mice over time and identifies previously unrecognized parallels and differences between murine, hamster and human responses to infection. We show commonality of interferon-regulated genes whilst confirming a greater activation of type 2 immune pathways in infected hamsters compared to mice. Cytokine genes and genes encoding immune checkpoints were markedly tissue specific and dynamic in their expression, and pathways focused on non-immune cells reflected tissue specific immunopathology. Our data also addresses the value of measuring peripheral blood transcriptomics as a potential window into underlying systemic disease. Conclusions: Our transcriptomic data, coupled with histopathologic analysis of the tissue response, provide an additional resource to underpin future mechanistic studies and to guide clinical research

Lutzomyia longipalpis Saliva Induces Heme Oxygenase-1 Expression at Bite Sites

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2018-12-19T16:23:43Z No. of bitstreams: 1 Luz NF. Lutzomyia longipalpis saliva...2018.pdf: 1955626 bytes, checksum: f84660a8c004e77cec0bb334c37bb074 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2018-12-19T16:46:42Z (GMT) No. of bitstreams: 1 Luz NF. Lutzomyia longipalpis saliva...2018.pdf: 1955626 bytes, checksum: f84660a8c004e77cec0bb334c37bb074 (MD5)Made available in DSpace on 2018-12-19T16:46:42Z (GMT). No. of bitstreams: 1 Luz NF. Lutzomyia longipalpis saliva...2018.pdf: 1955626 bytes, checksum: f84660a8c004e77cec0bb334c37bb074 (MD5) Previous issue date: 2018Fundação de Amparo a Pesquisa do Estado da Bahia (FAPESB) e Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and by the Intramural Research Program of the NIH, National Institute of Allergy and Infectious Diseases. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. NL is a fellowship recipient from CAPES Brazil; PM is a fellowship recipient from FAPESB; AV is a fellowship recipient from Programa Nacional de Pós-Doutorado/CAPES; CdO, UL, CB and VMB are senior investigators of CNPq.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Malaria and Vector Research. Vector Molecular Biology Section. Rockville, MD, United States.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Malaria and Vector Research. Vector Molecular Biology Section. Rockville, MD, USA.Federal University of Rio de Janeiro. Carlos Chagas Filho Biophysics Institute. Laboratory of Molecular Parasitology, Center of Health Science. Rio de Janeiro, RJ, Brazil.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Malaria and Vector Research. Vector Molecular Biology Section. Rockville, MD, USA.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Parasitic Diseases, Immunobiology Section. Bethesda, MD, USA.Fundação Oswaldo Cruz. Teresina, PI, Brasil.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Malaria and Vector Research. Vector Molecular Biology Section. Rockville, MD, USA.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil.Federal University of Rio de Janeiro. Carlos Chagas Filho Biophysics Institute. Laboratory of Molecular Parasitology, Center of Health Science. Rio de Janeiro, RJ, Brazil.Uniformed Services University of the Health Sciences. Infectious Diseases Division. Bethesda, MD, USA.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Fundação José Silveira, Bahia. Multinational Organization Network Sponsoring Translational and Epidemiological Research. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Malaria and Vector Research. Vector Molecular Biology Section. Rockville, MD, USA.National Institutes of Health. National Institute of Allergy and Infectious Diseases. Laboratory of Malaria and Vector Research. Vector Molecular Biology Section. Rockville, MD, United States.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil.Sand flies bite mammalian hosts to obtain a blood meal, driving changes in the host inflammatory response that support the establishment of Leishmania infection. This effect is partially attributed to components of sand fly saliva, which are able to recruit and activate leukocytes. Our group has shown that heme oxygenase-1 (HO-1) favors Leishmania survival in infected cells by reducing inflammatory responses. Here, we show that exposure to sand fly bites is associated with induction of HO-1 in vivo. Histopathological analyses of skin specimens from human volunteers experimentally exposed to sand fly bites revealed that HO-1 and Nrf2 are produced at bite sites in the skin. These results were recapitulated in mice ears injected with a salivary gland sonicate (SGS) or exposed to sand fly bites, indicating that vector saliva may be a key factor in triggering HO-1 expression. Resident skin macrophages were the main source HO-1 at 24-48 h after bites. Additionally, assays in vivo after bites and in vitro after stimulation with saliva both demonstrated that HO-1 production by macrophages was Nrf2-dependent. Collectively, our data demonstrates that vector saliva induces early HO-1 production at the bite sites, representing a major event associated with establishment of naturally-transmitted Leishmania infections