Vasconcellos LRC, Martimiano L, Dantas DP, Fonseca FM, Mata-Santos H, Travassos L, Mendez-Otero R, Bozza MT, Pimentel-Coelho PM. Intracerebral Injection of Heme Induces Lipid Peroxidation, Neuroinflammation, and Sensorimotor Deficits. Stroke. 2021 May;52(5):1788-1797.
DOI: 10.1161/STROKEAHA.120.031911
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Background and purpose: Heme is a red blood cell component released in the brain parenchyma following intracerebral hemorrhage. However, the study of the pathophysiological mechanisms triggered by heme in the brain is hampered by the lack of well-established in vivo models of intracerebral heme injection. This study aims to optimize and characterize a protocol of intrastriatal heme injection in mice, with a focus on the induction of lipid peroxidation, neuroinflammation and, ultimately, sensorimotor deficits. We also evaluated the involvement of NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3), an inflammasome sensor, in the behavior deficits induced by heme in this model.
Methods: Mice were injected with heme in the striatum for the evaluation of neuroinflammation and brain damage through histological and biochemical techniques. Immunoblot was used to evaluate the expression of proteins involved in heme/iron metabolism and antioxidant responses and the activation of the MAPK (mitogen-activated protein kinase) signaling pathway. For the assessment of neurological function, we followed-up heme-injected mice for 2 weeks using the rotarod, elevated body swing, and cylinder tests. Mice injected with the vehicle (sham), or autologous blood were used as controls.
Results: Heme induced lipid peroxidation and inflammation in the brain. Moreover, heme increased the expression of HO-1 (heme oxygenase-1), ferritin, p62, and superoxide dismutase 2, and activated the MAPK signaling pathway promoting pro-IL (interleukin)-1β production and its cleavage to the active form. Heme-injected mice exhibited signs of brain damage and reactive astrogliosis around the injection site. Behavior deficits were observed after heme or autologous blood injection in comparison to sham-operated controls. In addition, behavior deficits and IL-1β production were reduced in Nlrp3 knockout mice in comparison to wild-type mice.
Conclusions: Our results show that intracerebral heme injection induces neuroinflammation, and neurological deficits, in an NLRP3-dependent manner, suggesting that this is a feasible model to evaluate the role of heme in neurological.
Keywords: behavior; blood cells; cerebral hemorrhage; heme; inflammation.
da Fonseca-Martins AM, de Souza Lima-Gomes P, Antunes MM, de Moura RG, Covre LP, Calôba C, Rocha VG, Pereira RM, Menezes GB, Gomes DCO, Saraiva EM, de Matos Guedes HL. Leishmania Parasites Drive PD-L1 Expression in Mice and Human Neutrophils With Suppressor Capacity. Front Immunol. 2021 Jun 15;12:598943.
DOI: 10.3389/fimmu.2021.598943
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Neutrophils play an important role in the outcome of leishmaniasis, contributing either to exacerbating or controlling the progression of infection, a dual effect whose underlying mechanisms are not clear. We recently reported that CD4+ and CD8+ T cells, and dendritic cells of Leishmania amazonensis-infected mice present high expression of PD-1 and PD-L1, respectively. Given that the PD-1/PD-L1 interaction may promote cellular dysfunction, and that neutrophils could interact with T cells during infection, we investigated here the levels of PD-L1 in neutrophils exposed to Leishmania parasites. We found that both, promastigotes and amastigotes of L. amazonensis induced the expression of PD-L1 in the human and murine neutrophils that internalized these parasites in vitro. PD-L1-expressing neutrophils were also observed in the ear lesions and the draining lymph nodes of L. amazonensis-infected mice, assessed through cell cytometry and intravital microscopy. Moreover, expression of PD-L1 progressively increased in neutrophils from ear lesions as the disease evolved to the chronic phase. Co-culture of infected neutrophils with in vitro activated CD8+ T cells inhibits IFN-γ production by a mechanism dependent on PD-1 and PD-L1. Importantly, we demonstrated that in vitro infection of human neutrophils by L braziliensis induced PD-L1+ expression and also PD-L1+ neutrophils were detected in the lesions of patients with cutaneous leishmaniasis. Taken together, these findings suggest that the Leishmania parasite increases the expression of PD-L1 in neutrophils with suppressor capacity, which could favor the parasite survival through impairing the immune response.
Keywords: Leishmania; PD-L1; human cutaneous leishmaniasis; murine leishmaniasis; neutrophils; skin; supression.
Silva RCMC, Panis C, Pires BRB. Lessons from transmissible cancers for immunotherapy and transplant. Immunol Med. 2021 Dec 28:1-16.
DOI: 10.1080/25785826.2021.2018783
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The emergence of horizontal transmission of cancer between vertebrates is an issue that interests scientists and medical society. Transmission requires: (i) a mechanism by which cancer cells can transfer to another organism and (ii) a repressed immune response on the part of the recipient. Transmissible tumors are unique models to comprehend the responses and mechanisms mediated by the major histocompatibility complex (MHC), which can be transposed for transplant biology. Here, we discuss the mechanisms involved in immune-mediated tissue rejection, making a parallel with transmissible cancers. We also discuss cellular and molecular mechanisms involved in cancer immunotherapy and anti-rejection therapies.
Keywords: Transmissible cancer, MHC, transplant, immunotherapy
Oliveira-Maciel D, Dos-Santos JS, Oliveira-Silva G, Mello MF, da Fonseca-Martins AM, Carneiro MPD, Ramos TD, Firmino-Cruz L, Gomes DCO, Rossi-Bergmann B, de Matos Guedes HL. MPLA and AddaVax® Adjuvants Fail to Promote Intramuscular LaAg Vaccine Protectiveness against Experimental Cutaneous Leishmaniasis. Microorganisms. 2021 Jun 11;9(6):1272.
DOI: 10.3390/microorganisms9061272
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There is so far no vaccine approved for human leishmaniasis, mainly because of the lack of appropriate adjuvants. This study aimed to evaluate in mice the capacity of a mixture of monophosphoryl lipid A (MPLA) and AddaVax® adjuvants in enhancing the efficacy of a Leishvacin®-like vaccine comprised of Leishmania amazonensis whole antigens (LaAg). For that, mice were immunized with LaAg plus MPLA/AddaVax® by the intramuscular route (i.m.) prior to challenge with 2 × 105 and 2 × 106 living parasites. Immunization with LaAg alone reduced the lesion growth of the 2 × 105-challenged mice only in the peak of infection, but that was not accompanied by reduced parasite load, and thus not considered protective. Mice given a 2 × 106 -challenge were not protected by LaAg. The association of LaAg with MPLA/AddaVax® was able to enhance the cutaneous hypersensitivity response compared with LaAg alone. Despite this, there was no difference in proliferative cell response to antigen ex vivo. Moreover, regardless of the parasite challenge, association of LaAg with MPL/AddaVax® did not significantly enhance protection in comparison with LaAg alone. This work demonstrated that MPL/AddaVax® is not effective in improving the efficacy of i.m. LaAg vaccine against cutaneous leishmaniasis.
Keywords: Leishmania amazonensis; LaAg vaccine; adjuvants; MPLA; AddaVax®; intramuscular; immunization; C57BL/6
Ferreira AC, Soares VC, de Azevedo-Quintanilha IG, Dias SDSG, Fintelman-Rodrigues N, Sacramento CQ, Mattos M, de Freitas CS, Temerozo JR, Teixeira L, Damaceno Hottz E, Barreto EA, Pão CRR, Palhinha L, Miranda M, Bou-Habib DC, Bozza FA, Bozza PT, Souza TML. SARS-CoV-2 engages inflammasome and pyroptosis in human primary monocytes. Cell Death Discov. 2021 Mar 1;7(1):43.
DOI: 10.1038/s41420-021-00428-w
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Infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with leukopenia and uncontrolled inflammatory response in critically ill patients. A better comprehension of SARS-CoV-2-induced monocyte death is essential for the identification of therapies capable to control the hyper-inflammation and reduce viral replication in patients with 2019 coronavirus disease (COVID-19). Here, we show that SARS-CoV-2 engages inflammasome and triggers pyroptosis in human monocytes, experimentally infected, and from patients under intensive care. Pyroptosis associated with caspase-1 activation, IL-1ß production, gasdermin D cleavage, and enhanced pro-inflammatory cytokine levels in human primary monocytes. At least in part, our results originally describe mechanisms by which monocytes, a central cellular component recruited from peripheral blood to respiratory tract, succumb to control severe COVID-19.
Viana AS, Nunes Botelho AM, Moustafa AM, Boge CLK, Pires Ferreira AL, da Silva Carvalho MC, Guimarães MA, Costa BSS, de Mattos MC, Maciel SP, Echevarria-Lima J, Narechania A, O'Brien K, Ryan C, Gerber JS, Carvalho BTF, Figueiredo AMS, Planet PJ. Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus Associated with Bacteremia and Monocyte Evasion, Rio de Janeiro, Brazil. Emerg Infect Dis. 2021;27(11):2825-2835.
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We typed 600 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 51 hospitals in the Rio de Janeiro, Brazil, metropolitan area during 2014–2017. We found that multiple new clonal complex (CC) 5 sequence types had replaced previously dominant MRSA lineages in hospitals. Whole-genome analysis of 208 isolates revealed an emerging sublineage of multidrug-resistant MRSA, sequence type 105, staphylococcal cassette chromosome mec II, spa t002, which we designated the Rio de Janeiro (RdJ) clone. Using molecular clock analysis, we hypothesized that this lineage began to expand in the Rio de Janeiro metropolitan area in 2009. Multivariate analysis supported an association between bloodstream infections and the CC5 lineage that includes the RdJ clone. Compared with other closely related isolates, representative isolates of the RdJ clone more effectively evaded immune function related to monocytic cells, as evidenced by decreased phagocytosis rate and increased numbers of viable unphagocytosed (free) bacteria after in vitro exposure to monocytes.
Keywords: Brazil; MRSA; MRSA and other staphylococci; Rio de Janeiro; Staphylococcus aureus; antimicrobial resistance; bacteremia; bacteria; bacterial infection; bloodstream infections; drug resistance; methicillin-resistant Staphylococcus aureus; molecular epidemiology; monocyte evasion; monocytes; multidrug-resistance; phagocytosis; phylogenetics.
Gavino-Leopoldino D, Figueiredo CM, da Silva MOL, Barcellos LG, Neris RLS, Pinto LDM, Araújo SMB, Ladislau L, Benjamim CF, Da Poian AT, Clarke JR, Figueiredo CP, Assunção-Miranda I. Skeletal Muscle Is an Early Site of Zika Virus Replication and Injury, Which Impairs Myogenesis. J Virol. 2021 Oct 27;95(22):e0090421
DOI: 10.1128/JVI.00904-21
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Zika virus (ZIKV) infection became a worldwide concern due to its correlation with the development of microcephaly and other neurological disorders. ZIKV neurotropism is well characterized, but the role of peripheral viral amplification to brain infection remains unknown. Here, we found that ZIKV replicates in human primary skeletal muscle myoblasts, impairing its differentiation into myotubes but not interfering with the integrity of the already-formed muscle fibers. Using mouse models, we showed ZIKV tropism to muscle tissue either during embryogenesis after maternal transmission or when infection occurred after birth. Interestingly, ZIKV replication in the mouse skeletal muscle started immediately after ZIKV inoculation, preceding viral RNA detection in the brain and causing no disruption to the integrity of the blood brain barrier, and remained active for more than 2 weeks, whereas replication in the spleen and liver were not sustained over time. In addition, ZIKV infection of the skeletal muscle induces necrotic lesions, inflammation, and fiber atrophy. We also found a reduction in the expression of regulatory myogenic factors that are essential for muscle repair after injury. Taken together, our results indicate that the skeletal muscle is an early site of viral amplification and lesion that may result in late consequences in muscle development after ZIKV infection.
IMPORTANCE Zika Virus (ZIKV) neurotropism and its deleterious effects on central nervous system have been well characterized. However, investigations of the initial replication sites for the establishment of infection and viral spread to neural tissues remain underexplored. A complete description of the range of ZIKV-induced lesions and others factors that can influence the severity of the disease is necessary to prevent ZIKV’s deleterious effects. ZIKV has been shown to access the central nervous system without significantly affecting blood-brain barrier permeability. Here, we demonstrated that skeletal muscle is an earlier site of ZIKV replication, contributing to the increase of peripheral ZIKV load. ZIKV replication in muscle promotes necrotic lesions and inflammation and also impairs myogenesis. Overall, our findings showed that skeletal muscle is involved in pathogenesis and opens new fields in the investigation of the long-term consequences of early infection.
Keywords: Zika virus replication; muscle inflammation; myogenesis; pathogenesis; skeletal muscle; viral dissemination.
