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Abstract How macrophages in the tissue environment integrate multiple stimuli depends on the genetic background of the host, but this is still poorly understood. We investigate IL-4 activation of male C57BL/6 and BALB/c strain specific in vivo tissue-resident macrophages (TRMs) from the peritoneal cavity. C57BL/6 TRMs are more transcriptionally responsive to IL-4 stimulation, with induced genes associated with more super enhancers, induced enhancers, and topologically associating domains (TAD) boundaries. IL-4-directed epigenomic remodeling reveals C57BL/6 specific enrichment of NF-κB, IRF, and STAT motifs. Additionally, IL-4-activated C57BL/6 TRMs demonstrate an augmented synergistic response upon in vitro lipopolysaccharide (LPS) exposure, despite naïve BALB/c TRMs displaying a more robust transcriptional response to LPS. Single-cell RNA sequencing (scRNA-seq) analysis of mixed bone marrow chimeras indicates that transcriptional differences and synergy are cell intrinsic within the same tissue environment. Hence, genetic variation alters IL-4-induced cell intrinsic epigenetic reprogramming resulting in strain specific synergistic responses to LPS exposure.

Introdução: O Vírus da Imunodeficiência Humana (HIV) infecta os linfócitos T que expressam o receptor CD4 em sua superfície, comprometendo o sistema imunológico do indivíduo, predispondo-o a outras infecções¹. Uma delas é causada pelo citomegalovírus (CMV), que pode afetar órgãos como os olhos, provocando retinite², complicação caracterizada por lesões na retina3. Os antivirais ganciclovir e valganciclovir são utilizados para o tratamento da retinite por CMV em pessoas vivendo com HIV/Aids (PVHA). O ganciclovir é administrado pela via intravenosa, necessitando de ambiente ambulatorial ou hospitalar. O valganciclovir, pró-fármaco com biodisponibilidade equivalente ao ganciclovir, está disponível na forma de comprimido revestido e pode ser administrado pelo próprio indivíduo. Muitos custos diferentes incidem sobre os dois tratamentos e, na perspectiva da Avaliação de Tecnologias em Saúde, a fim de comparar os dois tratamentos, é necessária uma avaliação econômica para apontar qual seria a opção mais vantajosa na perspectiva do Sistema Único de Saúde. Objetivo: Realizar uma avaliação econômica comparando ganciclovir e valganciclovir para o tratamento da retinite por CMV em PVHA. Material e Método: Para a construção do modelo econômico, foram considerados os custos médicos diretos para o tratamento de retinite por CMV com os medicamentos ganciclovir 1mg/mL bolsa com 250mL e valganciclovir 450mg comprimido revestido. Os esquemas posológicos consideraram um indivíduo com 70kg e as médias de duração de tratamento descritas em literatura. As evidências de eficácia e segurança foram buscadas nas bases de dados LILACS (via Pubmed), EMBASE e Cochrane. A busca por preços foi realizada no Banco de Preços em Saúde (BPS) e Sistema de Gerenciamento da Tabela de Procedimentos, Medicamentos e Órteses, Próteses e Materiais Especiais do SUS (SIGTAP). Resultados: A busca por evidências concluiu que os dois medicamentos apresentam eficácia e segurança equivalentes4, por isso foi realizada uma avaliação de custo-minimização (ACM). Quanto à duração do tratamento, foram considerados 21 dias de terapia de indução para ambos os antivirais, 112 dias de terapia de manutenção para o ganciclovir e 150 dias de terapia de manutenção para o Valganciclovir5. O custo do tratamento com o ganciclovir, por paciente ao ano, foi estimado em R$29.861,19. O custo com o valganciclovir foi estimado em R$38.741,76. A ACM revelou que o tratamento com valganciclovir custa R$8.880,57 a mais que o tratamento com ganciclovir. Conclusões: A ACM não considerou aspectos importantes, como liberação de leitos ambulatoriais e hospitalares, além de questões como qualidade de vida e acessibilidade geográfica. Embora o uso de ganciclovir tenha apresentado um menor custo em relação ao valganciclovir, esse resultado pode estar superestimado devido à ausência de desfechos relacionados às preferências dos pacientes e ao custo de oportunidade associado à ocupação de leitos hospitalares.

Dental socket repair theoretically involves a constructive inflammatory immune response, which evolves from an initial M1 prevalence to a subsequent M2 dominance. In this scenario, the MEK1/2 signaling pathway is allegedly involved in M2 polarization. This study aimed to evaluate the impact of MEK1/2 pharmacological inhibition in the local host response and repair outcome. C57Bl/6-WT 8-week-old male mice were submitted to the extraction of the right upper incisor and treated (or not, control group) with MEK1/2 inhibitor PD0325901 (10 mg/kg/24 h/IP, MEK1/2i group) and analyzed at 0, 3, 7, and 14 days using microcomputed tomography, histomorphometry, birefringence, immunohistochemistry, and PCR array analysis. The results demonstrate that MEK1/2 inhibition limits the development of M2 response over time, being associated with lower expression of M2, MSCs, and bone markers, lower levels of growth and osteogenic factors, along with a higher expression of iNOS, IL-1b, IL-6, and TNF-α, as well inflammatory chemokines, indicating a predominantly M1 pro-inflammatory environment. This modulation of local inflammatory immune response is associated with impaired bone formation as demonstrated by microtomographic and histomorphometric data. The results show that MEK1/2 inhibition delays bone repair after tooth extraction, supporting the concept that M2 macrophages are essential elements for host response regulation and proper repair.

This study aimed to investigate the gene and protein expression of key inflammasome mediators in venous blood and skin biopsy samples from Brazilian psoriatic patients treated at the Pedro Ernesto University Hospital (HUPE). Samples were collected from both psoriatic patients and healthy controls. Gene expression was evaluated using quantitative reverse transcription polymerase chain reaction (qRT‒PCR), while protein levels were assessed through immunohistochemistry and multiplex immunoassays. Compared with those from control individuals, blood and skin biopsy samples from psoriatic patients had significantly higher mRNA levels of nucleotide-binding domain leucine-rich repeat (NLR) family pyrin domain containing receptor 1 (NLRP1), caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18). Immunohistochemical analysis revealed elevated protein levels of NLRP1, caspase-1, IL-1β, and IL-18 in psoriatic skin biopsies. Multiplex immunoassays revealed increased plasma levels of interferon-γ (IFN-γ), IL-1β, interleukin-17 A (IL-17 A), and tumor necrosis factor-α (TNF-α) in psoriatic patients. A positive correlation was observed between NLRP1 expression, disease severity, and the protein levels of IL-1β and TNF-α. In conclusion, in Brazilian psoriatic patients treated at HUPE, both blood and skin biopsy samples show increased expression of the NLRP1 inflammasome and its downstream mediators. Furthermore, NLRP1 expression is positively correlated with disease severity and the release of T helper 1-type cytokines, highlighting its potential role in the pathogenesis and progression of psoriasis. [ABSTRACT FROM AUTHOR]

Simple Summary: The bone-healing process involves the host inflammatory response, which in theory will mediate cell migration and the production of growth factors which will guide the repair process. In this scenario, macrophages are considered key elements in the development and resolution of inflammatory response. Interestingly, macrophages are highly responsive to microenvironment signals, which can guide their polarization into distinct functional phenotypes, denominated M1 (pro-inflammatory) and M2 (anti-inflammatory and pro-reparative). However, the factors responsible for macrophage polarization throughout bone repair remain unknown. In this study, we performed the pharmacological blockade of activated MEK1/2 kinases, intracellular elements theoretically involved in M2 polarization, to address their role in the dental socket repair process. After tooth extraction, our results demonstrate that the use of MEK1/2 inhibitor compound, namely PD0325901, limited the development of M2 response over time and resulted in an exacerbated non-resolving inflammatory response, which in turn impaired the bone repair outcome. Our results support the concept that chronic exacerbated inflammatory responses are not ideal for a proper bone repair outcome, pointing to M2 macrophages as essential elements for host response regulation and proper repair. Dental socket repair theoretically involves a constructive inflammatory immune response, which evolves from an initial M1 prevalence to a subsequent M2 dominance. In this scenario, the MEK1/2 signaling pathway is allegedly involved in M2 polarization. This study aimed to evaluate the impact of MEK1/2 pharmacological inhibition in the local host response and repair outcome. C57Bl/6-WT 8-week-old male mice were submitted to the extraction of the right upper incisor and treated (or not, control group) with MEK1/2 inhibitor PD0325901 (10 mg/kg/24 h/IP, MEK1/2i group) and analyzed at 0, 3, 7, and 14 days using microcomputed tomography, histomorphometry, birefringence, immunohistochemistry, and PCR array analysis. The results demonstrate that MEK1/2 inhibition limits the development of M2 response over time, being associated with lower expression of M2, MSCs, and bone markers, lower levels of growth and osteogenic factors, along with a higher expression of iNOS, IL-1b, IL-6, and TNF-α, as well inflammatory chemokines, indicating a predominantly M1 pro-inflammatory environment. This modulation of local inflammatory immune response is associated with impaired bone formation as demonstrated by microtomographic and histomorphometric data. The results show that MEK1/2 inhibition delays bone repair after tooth extraction, supporting the concept that M2 macrophages are essential elements for host response regulation and proper repair. [ABSTRACT FROM AUTHOR]

How macrophages in the tissue environment integrate multiple stimuli depends on the genetic background of the host, but this is still poorly understood. We investigate IL-4 activation of male C57BL/6 and BALB/c strain specific in vivo tissue-resident macrophages (TRMs) from the peritoneal cavity. C57BL/6 TRMs are more transcriptionally responsive to IL-4 stimulation, with induced genes associated with more super enhancers, induced enhancers, and topologically associating domains (TAD) boundaries. IL-4-directed epigenomic remodeling reveals C57BL/6 specific enrichment of NF-κB, IRF, and STAT motifs. Additionally, IL-4-activated C57BL/6 TRMs demonstrate an augmented synergistic response upon in vitro lipopolysaccharide (LPS) exposure, despite naïve BALB/c TRMs displaying a more robust transcriptional response to LPS. Single-cell RNA sequencing (scRNA-seq) analysis of mixed bone marrow chimeras indicates that transcriptional differences and synergy are cell intrinsic within the same tissue environment. Hence, genetic variation alters IL-4-induced cell intrinsic epigenetic reprogramming resulting in strain specific synergistic responses to LPS exposure. Genetic background affects how macrophages integrate multiple stimuli, e.g., to IL-4 in tissue environments. BALB/c macrophages show different transcriptional and epigenomic remodeling compared to C57BL/6, leading to distinct synergistic LPS responses. [ABSTRACT FROM AUTHOR]