Browsing by Author "Tognarelli Torres, Eduardo Ignacio"

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    Expression of heme oxygenase-1 in dendritic cells elicits T cell activation and confers protective immunity against HSV in an in vivo skin infection model
    (2023) Tognarelli Torres, Eduardo Ignacio; González Muñoz, Pablo Alberto; Pontificia Universidad Católica de Chile. Facultad de Ciencias Biológicas
    Los virus herpes simple tipo 1 (HSV-1) y tipo 2 (HSV-2) son altamente prevalentes en la población, en parte debido a su frecuente diseminación, aún desde individuos asintomáticos. La infección por HSV puede producir diversas manifestaciones clínicas incluyendo lesiones en piel, ceguera, o incluso encefalitis severa. Un aspecto importante de HSV es su capacidad para interferir con la viabilidad y función de células dendríticas (DC), células presentadoras de antígeno que inician y modulan la respuesta inmune en la interfase entre inmunidad innata y adaptativa. Una enzima del hospedero que participa en respuesta inducida frente a estrés es hemo oxigenasa-1 (HO-1), que se ha visto posee actividad antiviral contra HSV en células epiteliales y neuronales. En este estudio, buscamos evaluar si HO-1 puede modular positivamente la viabilidad de DCs y su función frente a la infección por HSV, lo cual podría ser clave para establecer inmunidad protectora contra estos virus. Nuestros hallazgos indican que HO-1 reduce la infección en DC por HSV-1 y HSV-2, y provee protección contra la muerte celular que inducen estos virus en estas células. La sobreexpresión de HO-1 en DCs no promueve un incremento de los marcadores de maduración y activación, por el contrario, aumentan la presencia de marcadores inhibitorios. Las DCs que expresan HO-1 y están infectadas con HSV, en ensayos de co-cultivo activaron células T CD4 vírgenes hacia fenotipos T regulador (Treg), determinado por la expresión de FoxP3 y OX40, y T helper (Th17) por la secreción de IL-17. La mejora de la función de DCs producto de la expresión de HO-1 se debería a un defecto en el ciclo de replicación de HSV por una disminución en la liberación de partículas infecciosas desde DCs, sin causar un efecto sobre la replicación del genoma y síntesis proteica viral. En un modelo de encefalitis, la transferencia de DCs que expresan HO-1 e infectadas con HSV causó que los animales susceptibles sufrieran un adelanto y aumento de la severidad de la patología. Mientras que, en un modelo de infección en piel, la transferencia de estas DCs demoró el inicio de la enfermedad y redujo el puntaje clínico de la infección por HSV. Adicionalmente, la inducción por HO-1 promueve la migración de DCs a linfonodos popliteos (pLNs) y estimuló células T CD4 Th17 y Tregs. Finalmente, se encontraron en lesiones de piel células Th17, mientras que hubo presencia de T CD8 y Treg a tiempos tempranos y tardíos, respectivamente. Estos resultados sugieren que la expresión de HO-1 en DCs promueve control viral, junto con una respuesta antinflamatoria contra HSV que puede proveer protección en un modelo animal de infección.
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    Heme Oxygenase-1 Expression in Dendritic Cells Contributes to Protective Immunity against Herpes Simplex Virus Skin Infection
    (MDPI, 2023) Tognarelli Torres, Eduardo Ignacio; Duarte Peñaloza, Luisa Fernanda; Farías León, Mónica Andrea; Cancino Prado, Felipe Andrés; Corrales Bonilla, Nicolas; Ibañez Irribarra, Francisco Javier; Riedel Soria, Claudia; Bueno Ramírez, Susan; Kalergis Parra,Alexis Mikes; González Muñoz, Pablo Alberto
    Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections are highly prevalent in the human population and produce mild to life-threatening diseases. These viruses interfere with the function and viability of dendritic cells (DCs), which are professional antigen-presenting cells that initiate and regulate the host's antiviral immune responses. Heme oxygenase-1 (HO-1) is an inducible host enzyme with reported antiviral activity against HSVs in epithelial cells and neurons. Here, we sought to assess whether HO-1 modulates the function and viability of DCs upon infection with HSV-1 or HSV-2. We found that the stimulation of HO-1 expression in HSV-inoculated DCs significantly recovered the viability of these cells and hampered viral egress. Furthermore, HSV-infected DCs stimulated to express HO-1 promoted the expression of anti-inflammatory molecules, such as PDL-1 and IL-10, and the activation of virus-specific CD4(+) T cells with regulatory (Treg), Th17 and Treg/Th17 phenotypes. Moreover, HSV-infected DCs stimulated to express HO-1 and then transferred into mice, promoted the activation of virus-specific T cells and improved the outcome of HSV-1 skin infection. These findings suggest that stimulation of HO-1 expression in DCs limits the deleterious effects of HSVs over these cells and induces a favorable virus-specific immune response in the skin against HSV-1.
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    Herpes simplex virus 2 infection: molecular association with HIV and novel microbicides to prevent disease.
    (2015) Suazo, P. A.; Tognarelli Torres, Eduardo Ignacio; Kalergis Parra, Alexis Mikes; González Muñoz, Pablo Alberto
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    Herpes simplex virus evasion of early host antiviral responses
    (2019) Tognarelli Torres, Eduardo Ignacio; Palomino Poblete, Tomás Francisco; Corrales Bonilla, Nicolás; Bueno Ramírez, Susan; Kalergis Parra. Alexis Mikes; González Muñoz, Pablo Alberto
    Herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) have co-evolved with humans for thousands of years and are present at a high prevalence in the population worldwide. HSV infections are responsible for several illnesses including skin and mucosal lesions, blindness and even life-threatening encephalitis in both, immunocompetent and immunocompromised individuals of all ages. Therefore, diseases caused by HSVs represent significant public health burdens. Similar to other herpesviruses, HSV-1 and HSV-2 produce lifelong infections in the host by establishing latency in neurons and sporadically reactivating from these cells, eliciting recurrences that are accompanied by viral shedding in both, symptomatic and asymptomatic individuals. The ability of HSVs to persist and recur in otherwise healthy individuals is likely given by the numerous virulence factors that these viruses have evolved to evade host antiviral responses. Here, we review and discuss molecular mechanisms used by HSVs to evade early innate antiviral responses, which are the first lines of defense against these viruses. A comprehensive understanding of how HSVs evade host early antiviral responses could contribute to the development of novel therapies and vaccines to counteract these viruses.
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    Immune-modulation by the human respiratory syncytial virus: focus on dendritic cells
    (2019) Tognarelli Torres, Eduardo Ignacio; Bueno Ramírez, Susan; González Muñoz, Pablo Alberto
    The human respiratory syncytial virus (hRSV) is the leading cause of pneumonia in infants and produces a significant burden in the elderly. It can also infect and produce disease in otherwise healthy adults and recurrently infect those previously exposed to the virus. Importantly, recurrent infections are not necessarily a consequence of antigenic variability, as described for other respiratory viruses, but most likely due to the capacity of this virus to interfere with the host's immune response and the establishment of a protective and long-lasting immunity. Although some genes encoded by hRSV are known to have a direct participation in immune evasion, it seems that repeated infection is mainly given by its capacity to modulate immune components in such a way to promote non-optimal antiviral responses in the host. Importantly, hRSV is known to interfere with dendritic cell (DC) function, which are key cells involved in establishing and regulating protective virus-specific immunity. Notably, hRSV infects DCs, alters their maturation, migration to lymph nodes and their capacity to activate virus-specific T cells, which likely impacts the host antiviral response against this virus. Here, we review and discuss the most important and recent findings related to DC modulation by hRSV, which might be at the basis of recurrent infections in previously infected individuals and hRSV-induced disease. A focus on the interaction between DCs and hRSV will likely contribute to the development of effective prophylactic and antiviral strategies against this virus.