Histone deacetylases (HDACs) are enzymes that regulate several processes, such as transcription, cell proliferation, differentiation and development. HDACs are classified as either Zn 2+ -dependent or NAD + -dependent enzymes. Over the years, experimental and clinical evidence has demonstrated that HDAC modulation is a critical process in neurodegenerative and psychiatric disorders. Nevertheless, most of the studies have focused on the role of Zn 2+ -dependent HDACs in the development of these diseases, although there is growing evidence showing that the NAD + -dependent HDACs, known as sirtuins, are also very promising targets. This possibility has been strengthened by reports of decreased levels of NAD + in CNS disorders, which can lead to alterations in sirtuin activation and therefore result in increased pathology. In this review, we discuss the role of sirtuins in neurodegenerative and neuropsychiatric disorders as well the possible rationale for them to be considered as pharmacological targets in future therapeutic interventions.LINKED ARTICLES: This article is part of a themed issue on Building Bridges in Neuropharmacology. To view the other articles in this section visit http://onlinelibrary.

Periodontitis is an inflammatory disease induced by a dysbiotic oral microbiome. Probiotics of the genus Bifidobacterium may restore the symbiotic microbiome and modulate the immune response, leading to periodontitis control. We evaluated the effect of two strains of Bifidobacterium able to inhibit Porphyromonas gingivalis interaction with host cells and biofilm formation, but with distinct immunomodulatory properties, in a mice periodontitis model. Experimental periodontitis (P+) was induced in C57Bl/6 mice by a microbial consortium of human oral organisms. B. bifidum 1622A [B+ (1622)] and B. breve 1101A [B+ (1101)] were orally inoculated for 45 days. Alveolar bone loss and inflammatory response in gingival tissues were determined. The microbial consortium induced alveolar bone loss in positive control (P + B-), as demonstrated by microtomography analysis, although P. gingivalis was undetected in oral biofilms at the end of the experimental period. TNF-α and IL-10 serum levels, and Treg and Th17 populations in gingiva of SHAM and P + B- groups did not differ. B. bifidum 1622A, but not B. breve 1101A, controlled bone destruction in P+ mice. B. breve 1101A upregulated transcription of Il-1β, Tnf-α, Tlr2, Tlr4, and Nlrp3 in P-B+(1101), which was attenuated by the microbial consortium [P + B+(1101)]. All treatments downregulated transcription of Il-17, although treatment with B. breve 1101A did not yield such low levels of transcripts as seen for the other groups. B. breve 1101A increased Th17 population in gingival tissues [P-B+ (1101) and P + B+ (1101)] compared to SHAM and P + B-. Administration of both bifidobacteria resulted in serum IL-10 decreased levels. Our data indicated that the beneficial effect of Bifidobacterium is not a common trait of this genus, since B. breve 1101A induced an inflammatory profile in gingival tissues and did not prevent alveolar bone loss. However, the properties of B. bifidum 1622A suggest its potential to control periodontitis.

Objective: Astrocytes play a significant role in the pathology of Multiple Sclerosis (MS). Nevertheless, for ethical reasons, most of the studies in these cells were performed on the Experimental Autoimmune Encephalomyelitis model. As there are significant differences between human and mouse cells, we aimed here to better characterize astrocytes from patients with MS (PwMS), focusing mainly on mitochondrial function and cell metabolism. Methods: We obtained and characterized induced pluripotent stem cell (iPSC)-derived astrocytes from three PwMS and three unaffected controls and performed functional assays including electron microscopy, flow cytometry, cytokine measurement, gene expression, in situ respiration, and metabolomics. Results: We detected several differences in MS astrocytes including: (i) enrichment of genes associated with mitophagy and neurodegeneration, (ii) increased mitochondrial fission and decreased mitochondrial to nuclear DNA ratio, indicating disruption of mitochondrial content, (iii) increased production of superoxide and MS-related proinflammatory chemokines, (iv) increased electron transport capacity and proton leak, in line with the increased oxidative stress, and (v) a distinct metabolic profile, with a deficiency in amino acid catabolism and increased sphingolipid metabolism, which have already been linked to MS. Interpretation: To our knowledge, this is the first study thoroughly describing the metabolic profile of iPSC-derived astrocytes from PwMS, and validating this model as a powerful tool to study disease mechanisms and to perform non-invasive drug targeting assays in vitro. Our findings recapitulate several disease features described in patients and provide new mechanistic insights into the metabolic rewiring of astrocytes in MS, which could be targeted in future therapeutic studies.

Atherosclerosis is caused by a monocyte-mediated infl ammatory process that, in turn, is stimulated by cytokines and adhesion molecules. Monocytes are then differentiated into macrophages, leading to the formation of arterial atherosclerotic plaques. Recently, guavirova leaf extracts from Campomanesia xanthocarpa (EG) have shown potential effects on the treatment of plaque formation by reducing cholesterol, LDL levels and serum oxidative stress. We evaluated the effect of EG on the viability of human monocytic and endothelial cell lines at three time points (24, 48 and 72 hours) and whether it can modulate the migration and in vitro expression of CD14, PECAM-1, ICAM-1, HLA-DR and CD105. Cell viability was affected only at higher concentrations and times. We observed decreased ICAM-1 expression in cells treated with 50 μg/ml EG and CD14 expression with IFN-γ and without IFN-γ. CD14 also decreased endothelial cell expression in the presence of IFN-γ and GE. We also found decreased expression of PECAM-1 when treated with EG and IFN-γ. In addition, EG-treated endothelial cells showed higher migration than the control group. Reduced expression of these markers and increased migration may lead to decreased cytokines, which may be contributing to decreased chronic infl ammatory response during atherosclerosis and protecting endothelial integrity.

Objective: Astrocytes play a significant role in the pathology of multiple sclerosis (MS). Nevertheless, for ethical reasons, most studies in these cells were performed using the Experimental Autoimmune Encephalomyelitis model. As there are significant differences between human and mouse cells, we aimed here to better characterize astrocytes from patients with MS (PwMS), focusing mainly on mitochondrial function and cell metabolism. Methods: We obtained and characterized induced pluripotent stem cell (iPSC)-derived astrocytes from three PwMS and three unaffected controls, and performed electron microscopy, flow cytometry, cytokine and glutamate measurements, gene expression, in situ respiration, and metabolomics. We validated our findings using a single-nuclei RNA sequencing dataset. Results: We detected several differences in MS astrocytes including: (i) enrichment of genes associated with neurodegeneration, (ii) increased mitochondrial fission, (iii) increased production of superoxide and MS-related proinflammatory chemokines, (iv) impaired uptake and enhanced release of glutamate, (v) increased electron transport capacity and proton leak, in line with the increased oxidative stress, and (vi) a distinct metabolic profile, with a deficiency in amino acid catabolism and increased sphingolipid metabolism, which have already been linked to MS. Interpretation: Here we describe the metabolic profile of iPSC-derived astrocytes from PwMS and validate this model as a very powerful tool to study disease mechanisms and to perform non-invasive drug targeting assays in vitro. Our findings recapitulate several disease features described in patients and provide new mechanistic insights into the metabolic rewiring of astrocytes in MS, which could be targeted in future therapeutic studies.

Este projeto recebeu suporte finaceiro através da Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP: N° de processo 2018/04326-1 e 2019/07820-0). Além disso houve apoio da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -Brasil (CAPES) -Código de Financiamento 001. RESUMOA Sirtuína 1 (SIRT1) pertence a classe 3 de histona desacetilase (HDAC3), a qual atua na diferenciação e ativação de células dendríticas (DCs). Portanto, ao modular fatores de transcrição, proteínas citoplasmáticas e componentes do metabolismo, SIRT1 pode controlar as funções das DCs e a polarização e ativação de linfócitos T.Nossa hipótese foi que a obesidade influenciaria a expressão de SIRT1 nas DCs, alterando seu fenótipo e função e, consequentemente, ativação das células T CD4+, o que exacerbaria a resposta inflamatória na obesidade. Observamos que as DCs derivadas da medula óssea, de órgãos linfoides secundários e do tecido adiposo visceral de animais obesos possuíam menor expressão de SIRT1. Além de BMDCs de animais obesos possuírem atividade de SIRT1 reduzida, quando comparado às BMDCs de animais magros. A ausência da expressão de SIRT1 nas DCs de animais obesos promoveu um impacto no metabolismo mitocondrial, sendo que a inibição de SIRT1 reduziu OXPHOS e aumentou o ECAR, contrastando com o tratamento com Resveratrol que promoveu um efeito oposto. A redução na SIRT1 aumentou a expressão de MHC-II, CD86 e CD40, aumentou da produção de IL-12p40 e diminuiu a produção de TGF-β, culminando com maior polarização de células T CD4+ para o subtipo Th1. O aumento na SIRT1 em DCs induziu uma polarização de linfócitos T para um perfil regulador (CD25+Foxp3+). Corroborando esses dados, animais seletivamente desprovidos de SIRT1 em DCs (SIRT1 ∆ ), submetidos ao modelo de obesidade induzida por dieta, tiveram maior resistência à insulina e menor tolerância à glicose. Estas alterações estavam correlacionadas com o aumento da quantidade de gordura visceral (VAT) dos animais SIRT1 ∆ e menor frequência de DCs do subtipo cDC1 e maior de cDC2. Ademais, a via de quinurenina estava reduzida em animais obesos, principalmente na ausência de SIRT1. Por fim, identificamos que SIRT1 regula positivamente a expressão de Ido1. Portanto, o presente trabalho identificou que SIRT1 controla o metabolismo e as funções de DC, via modulação da via da quinurenina e IDO1, fenótipos mais impactados na obesidade. O eixo SIRT1-IDO1 pode ser um novo alvo no tratamento da inflamação crônica presente na obesidade e de comorbidades associadas. Palavras chave: Sirtuína 1. Indoleamina 2,3 dioxigenase. Célula dendríticas.Obesidade.

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