Understanding the Metabolic Profile of Macrophages During the Regenerative Process in Zebrafish

In contrast to mammals, lower vertebrates, including zebrafish (Danio rerio), have the ability to regenerate damaged or lost tissues, such as the caudal fin, which makes them an ideal model for tissue and organ regeneration studies. Since several diseases involve the process of transition between fibrosis and tissue regeneration, it is necessary to attain a better understanding of these processes. It is known that the cells of the immune system, especially macrophages, play essential roles in regeneration by participating in the removal of cellular debris, release of pro- and anti-inflammatory factors, remodeling of components of the extracellular matrix and alteration of oxidative patterns during proliferation and angiogenesis. Immune cells undergo phenotypical and functional alterations throughout the healing process due to growth factors and cytokines that are produced in the tissue microenvironment. However, some aspects of the molecular mechanisms through which macrophages orchestrate the formation and regeneration of the blastema remain unclear. In the present review, we outline how macrophages orchestrate the regenerative process in zebrafish and give special attention to the redox balance in the context of tail regeneration

Cell lipid biology in infections: an overview

Lipids are a big family of molecules with a vast number of functions in the cell membranes, within the cytoplasm, and extracellularly. Lipid droplets (LDs) are the most common storage organelles and are present in almost every tissue type in the body. They also have structural functions serving as building blocks of cellular membranes and may be precursors of other molecules such as hormones, and lipoproteins, and as messengers in signal transduction. Fatty acids (FAs), such as sterol esters and triacylglycerols, are stored in LDs and are used in β-oxidation as fuel for tricarboxylic acid cycle (TCA) and adenosine triphosphate (ATP) generation. FA uptake and entrance in the cytoplasm are mediated by membrane receptors. After a cytoplasmic round of α- and β-oxidation, FAs are guided into the mitochondrial matrix by the L-carnitine shuttle system, where they are fully metabolized, and enter the TCA cycle. Pathogen infections may lead to impaired lipid metabolism, usage of membrane phospholipids, and LD accumulation in the cytoplasm of infected cells. Otherwise, bacterial pathogens may use lipid metabolism as a carbon source, thus altering the reactions and leading to cellular and organelles malfunctioning. This review aims to describe cellular lipid metabolism and alterations that occur upon infections

Lymphocyte Differentiation and Effector Functions

Univ São Paulo, Inst Biomed Sci, Dept Immunol, BR-05508000 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04021001 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04021001 São Paulo, BrazilWeb of Scienc

Innate Sensing of the Gut Microbiota: Modulation of Inflammatory and Autoimmune Diseases

The mammalian gastrointestinal tract harbors a diverse microbial community with which dynamic interactions have been established over millennia of coevolution. Commensal bacteria and their products are sensed by innate receptors expressed in gut epithelia and in gut-associated immune cells, thereby promoting the proper development of mucosal immune system and host homeostasis. Many studies have demonstrated that host-microbiota interactions play a key role during local and systemic immunity. Therefore, this review will focus on how innate sensing of the gut microbiota and their metabolites through inflammasome and toll-like receptors impact the modulation of a distinct set of inflammatory and autoimmune diseases. We believe that a better understanding of the fine-tuning that governs host-microbiota interactions will further improve common prophylactic and therapeutic applications.CNPqSao Paulo State Research Funding Agency (FAPESP)FAPESP fellowshipsUniv Sao Paulo, Inst Biomed Sci, Dept Immunol, Lab Transplantat Immunobiol, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Med, Div Nephrol, Sao Paulo, BrazilUniv Sao Paulo, Renal Pathophysiol Lab, Dept Clin Med, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Med, Div Nephrol, Sao Paulo, BrazilFAPESP: 12/02270-2Web of Scienc

Editorial: Macrophages role in integrating tissue Signals and Biological Processes in Chronic inflammation and Fibrosis

Univ Sao Paulo, Immunol Dept, Sao Paulo, BrazilINSERM, Paris, FranceUniv Fed Sao Paulo, Nephrol Div, Med Dept, Sao Paulo, BrazilUniv Sao Paulo, Renal Physiol Lab, Fac Med, Sao Paulo, BrazilUniv Fed Sao Paulo, Nephrol Div, Med Dept, Sao Paulo, BrazilWeb of Scienc

The dual effect of acetate on microglial TNF-α production

Introduction: Short-Chain Fatty Acids (SCFA) are products of intestinal microbial metabolism that can reach the brain and alter microglia in health and disease contexts. However, data are conflicting on the effect of acetate, the most abundant SCFA in the blood, in these cells. Objective: The authors aimed to investigate acetate as a modulator of the inflammatory response in microglia stimulated with LPS. Method: The authors used an immortalized cell line, C8-B4, and primary cells for in vitro treatments with acetate and LPS. Cell viability was analyzed by MTT, cytokine by RT-PCR, ELISA, and flow cytometry. The authors also performed in vivo and in silico analyses to study the role of acetate and the TNF-α contribution to the development of Experimental Autoimmune Encephalomyelitis (EAE). Results: Acetate co-administered with LPS was able to exacerbate the production of pro-inflammatory cytokines at gene and protein levels in cell lines and primary culture of microglia. However, the same effects were not observed when acetate was administered alone or as pretreatment, prior to the LPS stimulus. Additionally, pharmacological inhibition of histone deacetylase concomitantly with acetate and LPS led to decreased TNF-α production. In silico analysis showed a crucial role of the TNF-α pathway in EAE development. Moreover, acetate administration in vivo during the initial phase of EAE led to a better disease outcome and reduced TNF-α production. Conclusion: Treatment with acetate was able to promote the production of TNF-α in a concomitant LPS stimulus of microglia. However, the immune modulation of microglia by acetate pretreatment may be a component in the generation of future therapies for neurodegenerative diseases

Activation and Metabolic Shifting: An Essential Process to Mesenchymal Stromal Cells Function

To elucidate the basal metabolism of Mesenchymal Stromal Cells (MSCs), as well as knowing how they are activated, can bring important clues to a successful cell-based therapy. Naive MSCs, in their niche, mainly keep the local homeostasis and the pool of tissue stem cells. Once activated, by an injury, MSCs’ response leads to a lot of physiological differences in its metabolism that are responsible for its healing process. Since endogenous MSC seems to be ineffective in pathologic and aging conditions, cell-based therapy using MSC is focused on administration of exogenous MSC in patients to exert its healing functions. From quiescent to activated state, this “Metabolic Shifting” of MSC interferes directly in its secretion and cellular-derived particle generation. We will address here the differences between the MSCs activation phases and how they can modify the MSCs metabolism and its function. Moreover, understanding MSC in their niche and its damped function in pathologic and aging processes can improve stem cell-based therapies