Biology subjects

Oliveira, A. C.

Publications and source records attributed to Oliveira, A. C..

9 recordsLinked to original sources

bioRxiv2026

TREM2 Orchestrates Myeloid Cell Programming and Immune Dysregulation in Pulmonary Hypertension

Pulmonary hypertension (PH) is a progressive and fatal disease characterized by pulmonary vascular remodeling, inflammation, and immune dysregulation. Myeloid-derived suppressor cells (MDSCs) and macrophages contribute to PAH pathobiology; however, the molecular regulators of their pathological activation remain poorly defined. The triggering receptor expressed on myeloid cells 2 (TREM2) is an immunomodulatory receptor that shapes myeloid cell metabolism, survival, and immunosuppressive function, yet its role in PH has not been investigated. Methods: Single-cell RNA sequencing (scRNA-seq) data from human pulmonary artery tissue (GSE210248; n=3 PAH, n=3 donors) were analyzed to characterize TREM2 expression across cell populations. Wild-type (WT) and global TREM2 knockout (TREM2 KO) mice were exposed to chronic hypoxia (10% FiO2, 28 days). Hemodynamic, histological, flow cytometric, and ex vivo functional assessments were performed. TREM2 expression was measured by flow cytometry in circulating MDSCs from PAH patients (n=22) and healthy controls (n=13). Results: TREM2 was markedly enriched in monocyte/macrophage populations in PH pulmonary arteries and TREM2-high immune cells exhibited transcriptional downregulation of chemotaxis programs and upregulation of antigen processing and MHC II presentation pathways. TREM2 deficiency significantly attenuated hypoxia-induced RVSP increase, right ventricular dysfunction, pulmonary inflammation, and vascular remodeling. MDSCs from TREM2 KO mice exerted significantly less suppression of CD4+ and CD8+ T cell proliferation. TREM2 was significantly elevated in circulating MDSCs from PAH patients and showed a directional association with hemodynamic severity. Conclusions: TREM2 is a novel regulator of myeloid-driven immunosuppression and vascular remodeling in PAH and warrants investigation as a therapeutic target and biomarker.

immunology↗

bioRxiv2026

A microbiome-derived metabolite from Staphylococcus epidermidis inhibits Staphylococcus aureus biofilm formation and virulence

Staphylococcus epidermidis is a common member of the healthy skin microbiome that contributes to barrier function and protection against pathogen colonization. In contrast, Staphylococcus aureus is a major human pathogen and the leading cause of skin and soft tissue infections, owing in part to its robust biofilm-forming capacity and increasing antimicrobial resistance. We previously demonstrated that S. epidermidis cell-free conditioned media (CFCM) inhibit S. aureus biofilm formation by altering bacterial gene expression without affecting growth. Here, we identify the metabolite responsible for this activity. Bioactivity-guided fractionation of S. epidermidis CFCM revealed pyroglutamic acid (PCA) as the active antibiofilm compound. Commercially sourced PCA inhibited S. aureus biofilm formation and reduced adhesion to epithelial cells. In a murine skin infection model, PCA treatment significantly attenuated disease severity, accelerated wound healing, and reduced bacterial burden. Analysis of S. epidermidis CFCM by chromatography, nuclear magnetic resonance spectroscopy, and mass spectrometry confirmed the presence of PCA and identified it as the bioactive constituent responsible for antibiofilm activity. Together, these findings uncover a previously unrecognized mechanism by which S. epidermidis suppresses S. aureus virulence and highlight the potential of microbiome-derived metabolites as therapeutics for the prevention and treatment of S. aureus skin infections.

microbiology↗

bioRxiv2023

Vagus nerve mediated liver-brain axis is a major regulator of the metabolic landscape in the liver

BackgroundThe liver serves as a major energetic reservoir for other tissues and its metabolic function is controlled by humoral and neural factors. The vagus nerve innervating the gastrointestinal tract plays an important role in regulating peripheral metabolism and energy expenditure. Although the liver receives vagus nerve fibers, the impact of this circuitry in the regulation of hepatic metabolism is still poorly understood. MethodsHerein, we used a combination of quantitative proteomics and in vivo imaging techniques to investigate the impact of the vagus nerve on liver metabolism. ResultsVagus nerve shapes the metabolic framework of the liver, as surgical ablation (vagotomy; VNX) of this circuitry led to a significant alteration of the hepatic proteome landscape. Differential protein expression and pathway enrichment analyses showed that glycolytic and fatty acid biosynthesis were increased following VNX, whereas {beta}-oxidation was decreased. This metabolic shift facilitated lipid accumulation in hepatocytes. Furthermore, VNX worsened liver steatosis following high-carbohydrate or high-fat dietary challenges. ConclusionsThis study describes the liver-brain axis mediated by the vagus nerve as an important regulator of the hepatic metabolic landscape. HighlightsO_LIVagus nerve is a novel regulator of the hepatic metabolic landscape. C_LIO_LIAblation of vagus nerve neural circuit by vagotomy resulted in a metabolic shift towards glycolysis and fatty acid biosynthesis. C_LIO_LILipid accumulation was increased in vagotomized mice fed with a standard diet. C_LIO_LILiver steatosis was increased following dietary challenges with high-carbohydrate or high-fat diets. C_LIO_LIVagus nerve can be a promising new target for NAFLD treatment. C_LI

physiology↗

bioRxiv2022

Cell dichotomous role of STING in pulmonary hypertension

RationalePatients with constitutive activation of DNA sensing pathway through stimulator of interferon genes (STING), such as those with STING-Associated Vasculopathy with onset in Infancy (SAVI), frequently have complications related to pulmonary hypertension (PH). However, the role of STING-signaling in adult PH patients is heretofore undescribed. ObjectiveTo investigate the role of STING in PH development. Methods and ResultsPH was induced in global STING deficient or cell-specific STING deficient mice using either bleomycin or chronic hypoxia exposure. PH development was evaluated with right ventricular systolic pressure, Fulton index, histological and flow cytometric measurements. STING expression in patient lungs were examined using both immunohistochemistry and flow cytometry. Herein, we describe how STING overactivation in a SAVI mouse model results in a baseline elevation in pulmonary pressures, while global STING deficiency protects mice from PH development. Furthermore, STING-associated PH appears to be independent of type I Interferon (IFN) signaling. We further demonstrate a cellular dichotomous role of STING in PH development with STING expression by smooth muscle cells contributing to PH, and its activation on myeloid cells being pivotal in severe disease prevention. Finally, we demonstrate a STING-PD-L1 axis as necessary for disease progression, suggesting future potential therapeutic applications. ConclusionsOverall, these data provide concrete evidence of STING involvement in PH, establishing biologic plausibility for STING-related therapies in PH treatment. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=198 HEIGHT=200 SRC="FIGDIR/small/518422v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@7f5b50org.highwire.dtl.DTLVardef@143e485org.highwire.dtl.DTLVardef@4fe1a4org.highwire.dtl.DTLVardef@66fe26_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2021

A switch in the development: microRNA arm usage screening in zebrafish suggests an important role of arm switching events in ontogenesis

In metazoan, regulatory molecules tightly control gene expression. Among them, microRNAs (miRNAs) are key regulators of several important features, like cell proliferation, differentiation, and homeostasis. During miRNA biogenesis, the canonical strand that loads onto RISC can be switched, in a process called "arm switching." Due to the miRNA-to-target pairing peculiarities, switching events can lead to changes on the gene-targeted repertoire, promoting the modulation of a distinct set of biological routes. To understand how these events affect cell regulation, we conducted an extensive and detailed in silico analysis of RNA-seq datasets from several tissues and key developmental stages of zebrafish. We identified interesting patterns of miRNA arm switching occurrence, mainly associated with the control of protein coding genes during embryonic development. Additionally, our data show that miRNA isoforms (isomiRs) play an important role in differential arm usage. Our findings provide new insights on how such events emerge and coordinate gene expression regulation, opening perspectives for novel investigations in the area.

bioinformatics↗

bioRxiv2020

Equine hyperimmune globulin raised against the SARS-CoV-2 spike glycoprotein has extremely high neutralizing titers

We used the trimeric spike (S) glycoprotein (residues 1-1208) in the prefusion conformation to immunize horses for production of hyperimmune globulins against SARS-CoV-2. Serum antibody titers measured by anti-spike ELISA were above 1:1,000,000, and neutralizing antibody titer was 1:14,604 (average PRNT90), which is 140-fold higher than the average neutralizing titer of plasma from three convalescent COVID-19 patients analyzed for comparison. Using the same technology routinely used for industrial production of other horse hyperimmune products, plasma from immunized animals was pepsin digested to remove the Fc portion and purified, yielding a F(ab)2 preparation with PRNT90 titers 150-fold higher than the neutralizing titers in human convalescent plasma. Repeating the hyperimmunization in a second group of horses confirmed the very high neutralizing titers in serum and in a GMP clinical F(ab)2 lot. Virus-neutralizing activity in samples from mice that received the F(ab)2 preparation was detected even three days after injection, indicating an appropriate half-life for therapeutic intervention. These results supported the design of a clinical trial (identifier NCT04573855) to evaluate safety and efficacy of this horse F(ab)2 preparation.

immunology↗

bioRxiv2019

The subtle balance of insulin and thyroxine on survival and development of primordial follicles cultured in vitro enclosed in ovarian tissue

Thyroid hormones have presented a positive hormonal interaction on follicular development of secondary follicles and oocytes from antral follicles; however, the effect of thyroid hormones on primordial follicles is unclear. Here we investigated the in vitro effects of combined insulin and thyroxine on caprine primordial follicle survival and development. Ovarian tissues were cultured for 1 or 7 days using 10 ng/ml (low) or 10 {micro}g/ml (high) insulin in the absence or presence of thyroxine at 0.5, 1 or 2 {micro}g/ml. Thereafter, follicular survival and development, gene expression related to apoptosis (Bcl2/Bax), insulin and thyroid receptors, and estradiol and reactive oxygen species production were evaluated. In low-insulin conditions, supplementation with 2 {micro}g/ml thyroxine maintained follicular survival similar to non-cultured control, while 0.5 {micro}g/ml thyroxine enhanced the survival (P<0.05) in comparison to thyroxine-free treatment. Only treatments containing low-insulin and thyroxine at 0.5 or 2 {micro}g/ml increased (P<0.05) reactive oxygen species production from day 1 to day 7. Contrarily to high-insulin containing medium, the presence of thyroxine in low-insulin medium yielded higher stromal cell density (P<0.05). There were higher (P<0.05) estradiol production and Bcl2/Bax ratio in low-insulin versus high-insulin treatments on day 1 and 7, respectively. High levels of both insulin and thyroxine showed better follicular development (P<0.05), yielding great follicle and oocyte diameter. Finally, the high-insulin level led to insulin and thyroid receptors expression reduction as compared to non-cultured control. In conclusion, the combination of low concentrations of insulin and thyroxine better maintained follicle survival, while high levels ensured better follicular development.

physiology↗

bioRxiv2019

From 3D to 3D: isolation of mesenchymal stem/stromal cells into a three-dimensional human platelet lysate matrix

Mesenchymal stem/stromal cells (MSCs) are considered an important candidate in cell therapy and tissue engineering approaches. The culture of stem cells in a 3D environment is known to better resemble the in vivo situation and to promote therapeutically relevant effects in isolated cells. Therefore, the aim of this study was to develop an approach for the isolation of MSCs from adipose tissue into a 3D environment. Furthermore, the use of cryoprotective medium for cryopreservation of whole adipose tissue was evaluated. For the isolation of MSCs, a novel human platelet lysate-based hydrogel was used as matrix and the migration, yield, viability and metabolic activity of cells from the 3D matrix were compared to cells from 2D explant culture. Also, the surface marker profile and differentiation capacity of MSCs from the 3D matrix were evaluated and compared to MSCs from isolation by enzymatic treatment. We found that cryopreservation of whole adipose tissue is feasible, and therefore adipose tissue can be stored and is available for MSC isolation on demand. Also, we demonstrate the isolation of MSCs into the 3D matrix and that cells from this condition display a similar phenotype and differentiation capacity like MSCs derived by traditional isolation procedure. The presented approach allows, for the first time, to isolate MSCs directly into a soft 3D hydrogel environment, avoiding any contact to a 2D plastic culture surface.\n\nSignificance StatementIn this paper we present a new method for the isolation of mesenchymal stem cells. Usually, these cells grow on two-dimensional plastic surfaces which is far away from their physiologic environment. Our new method allows for the first time the direct outgrowth of cells from primary tissue into a three-dimensional environment, avoiding any contact to a two-dimensional plastic surface. In future, this will allow an entirely three-dimensional in vitro cultivation of stem cells. Using 3D isolated cells will probably also increase the physiologic relevance of in vitro models.

cell biology↗

bioRxiv2019

Yellow Fever Vaccine Protects Resistant and Susceptible Mice Against Zika Virus Infection

Zika virus (ZIKV) emerged as an important infectious disease agent in Brazil in 2016. Infection usually leads to mild symptoms but severe congenital neurological disorders and Guillain-Barre syndrome have been reported following ZIKV exposure. The development of an effective vaccine against Zika virus is a public health priority, encouraging the preclinical and clinical studies of different vaccine strategies. Here, we describe the protective effect of an already licensed attenuated yellow fever vaccine (17DD) on type-I interferon receptor knockout mice (A129) and immunocompetent (BALB/c) mice infected with ZIKV. Yellow fever virus vaccination results in robust protection against ZIKV, with decreased mortality in the A129 mice, a reduction in the cerebral viral load in all mice, and weight loss prevention in the BALB/c mice. Despite the limitation of yellow fever (17DD) vaccine to elicit antibody production and neutralizing activity against ZIKV, we found that YF immunization prevented the development of neurological impairment induced by intracerebral virus inoculation in adult. Although we used two vaccine doses in our protocol, a single dose was protective, reducing the cerebral viral load. Different Zika virus vaccine models have been tested; however, our work shows that an efficient and certified vaccine, available for use for several decades, effectively protects mice against Zika virus infection. These findings open the possibility for using an available and inexpensive vaccine to a large-scale immunization in the event of a Zika virus outbreak.

immunology↗