Genetic variants in ATP2B2 as risk factors for mortality in patients unrelated but not associated with families with severe COVID-19

Introduction

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of Coronavirus Disease 2019 (COVID-19). The disease has a wide range of clinical manifestations, from asymptomatic to severe. Ancestral contribution, sex, immune response, and genetic factors influence the presentation of the disease. The objective of the present study was to validate these genetic variants in patients with severe COVID-19 who died and in survivor patients. Methods: Single nucleotide variants (SNVs) in six genes: ATPase plasma membrane Ca2+ transporting 2 (ATP2B2), transmembrane serine protease 2 (TMPRSS2), dedicator of cytokinesis 2 (DOCK2), (interferon alpha and beta receptor subunit 2) IFNAR2, tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), and tumor necrosis factor receptor superfamily, member 1B (TNFRSF1B), were explored in two groups: the first consisted of severe COVID-19-related patients (familial cases from 58 families, n = 130), and the second group of unrelated severe COVID-19 patients (n = 1045). In each study group, death was evaluated as the outcome.

Results

In non-related patients with severe COVID-19, carriers of GG genotype (rs2289274) in the ATP2B2 gene showed a high-risk probability of non-surviving (OR = 1.43). Survival analysis to 75 days indicates that carriers of GG have a higher risk than GA or AA genotypes (p = 0.0059). The haplotype GG (rs2289273-rs2289274) in ATP2B2 was found to be associated with a high risk of death in severe non-related COVID-19 patients. No significant associations were found between severe COVID-19-related patients and SNVs in ATP2B2, TMPRSS2, DOCK2, IFNAR2, TNFRSF1A, or TNFRSF1B.

Conclusions

Unrelated patients with severe COVID-19 that carry the GG genotype (rs2289274) in ATP2B2 showed a high death risk. Survival analysis to 75 days indicates that carriers of GG have a higher risk of non-survival compared to GA or AA genotypes.

Participation of Single-Nucleotide Variants in IFNAR1 and IFNAR2 in the Immune Response against SARS-CoV-2 Infection: A Systematic Review

Host genetic factors significantly influence susceptibility to SARS-CoV-2 infection and COVID-19 severity. Among these genetic factors are single-nucleotide variants (SNVs). IFNAR2 and IFNAR1 genes have been associated with severe COVID-19 in populations from the United Kingdom, Africa, and Latin America. IFNAR1 and IFNAR2 are subunits forming the type I interferon receptor (IFNAR). SNVs in the IFNAR genes impact protein function, affecting antiviral response and disease phenotypes. This systematic review aimed to describe IFNAR1 and IFNAR2 variants associated with COVID-19 susceptibility and severity. Accordingly, the current review focused on IFNAR1 and IFNAR2 studies published between January 2021 and February 2023, utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol. The electronic search was conducted in PubMed databases using Boolean operators and inclusion and exclusion criteria. Of the 170 literature pieces, 11 studies were included. We include case reports of rare SNVs, defined by minor allele frequency (MAF) < 1%, and genome-wide associated studies (GWAS). Variants in IFNAR1 and IFNAR2 could potentially be new targets for therapies that limit the infection and the resulting inflammation by SARS-CoV-2 infection.

The role of TNF receptors as mediators of chronic vasculitis in possible milder forms of the CNS tuberculosis

INTRODUCTION

Central nervous system (CNS) tuberculosis (TB) is the most severe form of TB due to its high mortality and functional sequelae. There are several differential diagnoses for TB; and, it can also cause secondary conditions, such as vasculitis.

METHODOLOGY

155 biopsies, corresponding to 155 different patients out of 5,386 registered biopsies from 2008-2013, met the criteria of unknown etiology vasculitis and evidence of cerebral vascular disease. These were analyzed to assess the presence of central nervous system TB. The selected cases were assessed with Suzaan Marais (SM) criteria for clinical tuberculosis. After that, Ziehl-Neelsen (ZN) staining and polymerase chain reaction (PCR) were performed to amplify a fragment of the insertion sequence IS6110 of M. tuberculosis. 21 patients met the criteria for definitive tuberculosis by ZN staining and PCR, and 2 met the criteria for possible tuberculosis. Tumor necrosis factor (TNF)-α, TNF-R1, and TNF-R2 were determined by immunohistochemistry in histological sections from formalin-fixed paraffin-embedded (FF-PE) tissues in the 23 selected patients.

RESULTS

Granulomatous TB was present in almost half of the cases. TNF-R1 and TNF-R2 were expressed mainly in blood vessels, histiocytes, and macrophages. TNF-R2 expression was higher than the other markers, which suggests an anti-inflammatory response against M. tuberculosis.

CONCLUSIONS

The histopathological presentation of TB is not always limited to granulomas, abscesses, or meningitis; there are also clinical presentations characterized only with chronic inflammation of nervous and vascular tissue.

Apocynin, an NADPH Oxidase Enzyme Inhibitor, Prevents Amebic Liver Abscess in Hamster

Amebiasis is an intestinal infection caused by Entamoeba histolytica. Amebic liver abscess (ALA) is the most common extraintestinal complication of amebiasis. In animal models of ALA, neutrophils have been shown to be the first cells to come into contact with Entamoeba histolytica during the initial phase of ALA. One of the multiple mechanisms by which neutrophils exhibit amebicidal activity is through reactive oxygen species (ROS) and the enzyme NADPH oxidase (NOX2), which generates and transports electrons to subsequently reduce molecular oxygen into superoxide anion. Previous reports have shown that ROS release in the susceptible animal species (hamster) is mainly stimulated by the pathogen, in turn provoking such an exacerbated inflammatory reaction that it is unable to be controlled and results in the death of the animal model. Apocynin is a natural inhibitor of NADPH oxidase. No information is available on the role of NOX in the evolution of ALA in the hamster, a susceptible model. Our study showed that administration of a selective NADPH oxidase 2 (NOX2) enzyme inhibitor significantly decreases the percentage of ALA, the size of inflammatory foci, the number of neutrophils, and NOX activity indicated by the reduction in superoxide anion (O2-) production. Moreover, in vitro, the apocynin damages amoebae. Our results showed that apocynin administration induces a decrease in the activity of NOX that could favor a decrease in ALA progression.

LDH-A Promotes Metabolic Rewiring in Leucocytes from the Intestine of Rats Treated with TNBS

Although the aetiology of inflammatory bowel diseases (IBDs) is still unknown, one of their main characteristics is that the immune system chronically affects the permeability of the intestinal lamina propria, in turn altering the composition of the microbiota. In this study, the TNBS rat model of colitis was used because it contains a complex inflammatory milieu of polymorphonuclear cells (PMN) and lymphocytes infiltrating the lamina propria. The aim of the present study was to investigate six dehydrogenases and their respective adaptations in the tissue microenvironment by quantifying enzymatic activities measured under substrate saturation conditions in epithelial cells and leukocytes from the lamina propria of rats exposed to TNBS. Our results show that in the TNBS group, an increased DAI score was observed due to the presence of haemorrhagic and necrotic areas in the colon. In addition, the activities of G6PDH and GADH enzymes were significantly decreased in the epithelium in contrast to the increased activity of these enzymes and increased lactate mediated by the LDH-A enzyme in leukocytes in the lamina propria of the colon. Over the past years, evidence has emerged illustrating how metabolism supports aspect of cellular function and how a metabolic reprogramming can drive cell differentiation and fate. Our findings show a metabolic reprogramming in colonic lamina propria leukocytes that could be supported by increased superoxide anion.

Characterization of the lung microbiome and inflammatory cytokine levels in women exposed to environmental risk factors: A pilot study

INTRODUCTION

Lung microbiome dysbiosis affects the immune system balance and promotes lung inflammation. We aimed to characterize and compare the lung bacteriome composition and the cytokine profile in women with normal lung function exposed to risk factors for chronic lung diseases (tobacco smoking and biomass-burning smoke exposure).

METHODS

We included women with biomass-burning smoke exposure (BE, n = 11) and current smokers women (TS, n = 10). The bacteriome composition was performed in induced sputum, sequencing the 16 rRNA gene. Cytokine levels were measured using enzyme-linked immunosorbent assay multiplex assay in the supernatant of induced sputum. For quantitative variables, we used medians and minimum and maxim values. For the amplicon sequence variants (ASV) differential abundance testing between groups.

RESULTS

At the taxa level, the phylum Proteobacteria was found in a higher proportion in the TS group concerning BE (p = .045); however, after the false discovery rate adjustment, this difference was not retained (p = .288). We found a higher concentration of IL-1β in the TS group than in the BE group (248.6 vs. 177.9 pg/mL, p = .010). Women with high biomass-burning smoke exposure in an hour per day had a positive correlation with the abundance of Bacteroidota (ρ = 0.71, p = .014) and Fusobacteriota (ρ = 0.73, p = .011). FEV1/FVC had a positive correlation with an abundance of Bacteroidota, Proteobacteria, and Fusobacteria (ρ = 0.74, p = .009, ρ = 0.85, p = .001, and ρ = 0.83, p = .001, respectively). In tobacco smoking, women had a positive correlation (ρ = 0.77, p = .009) between cigarettes per day and Firmicutes' abundance.

CONCLUSION

Compared to biomass-burning smoke-exposed women, current smokers have poor lung function and high levels of IL-1β in sputum. Women with biomass-burning smoke exposure present an increased abundance of Bacteroidota and Fusobacteriota.

CD4+/IL‑4+ lymphocytes of the lamina propria and substance P promote colonic protection during acute stress

Life stress may influence symptom onset and severity in certain gastrointestinal disorders in association with a dysregulated intestinal barrier. It has been widely accepted that stress triggers the hypothalamus‑pituitary‑adrenal (HPA) axis, releasing corticosterone, which promotes intestinal permeability. In response, colonic inflammation alters mucosal immune homeostasis and destroys the colonic architecture, leading to severe intestinal diseases. Endogenous substance P (SP) does not inhibit the initial extent of the HPA axis response to restraint stress, but it reduces the duration of the stress, suggesting that SP plays an important role in the transition between acute and chronic stress. The present study aimed to investigate the effect of two groups of mice exposed to stress, including acute and chronic stress. The corticosterone was evaluated by ELISA, colon samples were obtained to detected polymorphonuclear cells by hematoxylin and eosin staining, goblet and mast cells were identified by immunocytochemistry and cytokine‑producing CD4+ T cells were analyzed by flow cytometry assays, adhesion proteins in the colon epithelium by western blotting and serum SP levels by ELISA. The results demonstrated an increase in the number of polymorphonuclear, goblet and mast cells, a decrease in claudin‑1 expression and an elevation in E‑cadherin expression during acute stress. Increased E‑cadherin expression was also detected during chronic stress. Moreover, it was found that acute stress caused a shift towards a predominantly anti‑inflammatory immune response (T helper 2 cells), as shown by the increase in the percentage of CD4+/IL‑6+ and CD4+/IL4+ lymphocytes in the lamina propria and the increase in serum SP. In conclusion, this response promoted colonic protection during acute stress.

The SNP rs13147758 in the HHIP Gene Is Associated With COPD Susceptibility, Serum, and Sputum Protein Levels in Smokers

Background

Genetic association studies have identified single nucleotide polymorphisms (SNPs) related to chronic obstructive pulmonary disease (COPD) susceptibility. The aim of this study was to identify HHIP genetic variants associated with COPD, pulmonary function, and serum and sputum HHIP protein levels in Mexican mestizo smokers.

Materials and Methods

Association analysis was performed by carrying out a case-control study in Mexican mestizo smokers comprised of two groups: tobacco-smoking subjects with COPD (COPD-TS, n = 222) and smokers without COPD (SWOC, n = 333). We evaluated three SNPs (rs13147758, rs1828591, and rs13118928) in the HHIP gene. Allele discrimination was accomplished by qPCR using TaqMan probes, and determination of protein levels in the serum and sputum supernatants (SS) was performed using ELISA.

Results

Statistically significant differences were observed in the rs13147758 GG genotype (adjusted p = 0.014, OR = 1.95) and the rs13147758-rs1828591 GA haplotype (p = 6.6E-06, OR = 2.65) in the case-control comparison. HHIP protein levels were elevated in SS samples from the COPD-TS group compared to those from the SWOC group (p = 0.03). Based on genotype analysis, HHIP protein levels were lower in the serum samples of rs13147758 GG genotype carriers in the COPD-TS group than in the serum samples of rs13147758 GG genotype carriers from the SWOC group (p < 0.05), but there were no differences in the sputum samples.

Conclusion

The rs13147758 GG genotype and the rs13147758-rs1828591 GA haplotype are associated with susceptibility to COPD. Furthermore, an association in protein levels was observed between the HHIP rs13147758 genotype and COPD in Mexican mestizo smokers.

Participation of HHIP Gene Variants in COPD Susceptibility, Lung Function, and Serum and Sputum Protein Levels in Women Exposed to Biomass-Burning Smoke

BACKGROUND

A variety of organic materials (biomass) are burned for cooking and heating purposes in poorly ventilated houses; smoke from biomass combustion is considered an environmental risk factor for chronic obstructive pulmonary disease COPD. In this study, we attempted to determine the participation of single-nucleotide variants in the HHIP (hedgehog-interacting protein) gene in lung function, HHIP serum levels, and HHIP sputum supernatant levels in Mexican women with and without COPD who were exposed to biomass-burning smoke.

METHODS

In a case-control study (COPD-BS, n = 186, BBES, n = 557) in Mexican women, three SNPs (rs13147758, rs1828591, and rs13118928) in the HHIP gene were analyzed by qPCR; serum and supernatant sputum protein levels were determined through ELISA.

RESULTS

The rs13118928 GG genotype is associated with decreased risk (p = 0.021, OR = 0.51, CI95% = 0.27-0.97) and the recessive genetic model (p = 0.0023); the rs1828591-rs13118928 GG haplotype is also associated with decreased risk (p = 0.04, OR = 0.65, CI95% 0.43-0.98). By the dominant model (rs13118928), the subjects with one or two copies of the minor allele (G) exhibited higher protein levels. Additionally, two correlations with the AG genotype were identified: BBES with FEV1 (p = 0.03, r2 = 0.53) and COPD-BS with FEV1/FVC (p = 0.012, r2 = 0.54).

CONCLUSIONS

Single-nucleotide variants in the HHIP gene are associated with decreased COPD risk, higher HHIP serum levels, and better lung function in Mexican women exposed to biomass burning.

Single Nucleotide and Copy-Number Variants in IL4 and IL13 Are Not Associated with Asthma Susceptibility or Inflammatory Markers: A Case-Control Study in a Mexican-Mestizo Population

BACKGROUND

Asthma is a complex and chronic inflammatory airway disease. Asthma's etiology is unknown; however, genetic and environmental factors could affect disease susceptibility. We designed a case-control study aimed to evaluate the role of single-nucleotide polymorphisms (SNP), and copy-number variants (CNV) in the IL4 and IL13 genes in asthma susceptibility and their participation in plasma cytokine levels depending on genotypes Methods: We include 486 subjects, divided into asthma patients (AP, n = 141) and clinically healthy subjects (CHS, n = 345). We genotyped three SNP, two in the IL4 and two in the IL13 gene; also, two CNVs in IL4. The IL-4, IL-13 and IgE plasma levels were quantified.

RESULTS

Biomass-burning smoke exposure was higher in the AP group compared to CHS (47.5% vs. 20.9%; p < 0.01, OR = 3.4). No statistical differences were found in the genetic association analysis. In both CNV, we only found the common allele. For the analysis of IL-4, IL-13, and IgE measures stratified by genotypes, no significant association or correlation was found.

CONCLUSION

In the Mexican-mestizo population, SNPs neither CNVs in IL4 nor IL13 are associated with asthma susceptibility or involved serum cytokine levels. Biomass-burning smoke is a risk factor in asthma susceptibility.

Effect of SNPs in HSP Family Genes, Variation in the mRNA and Intracellular Hsp Levels in COPD Secondary to Tobacco Smoking and Biomass-Burning Smoke

Heat shock proteins (HSP) genes are a superfamily responsible for encoding highly conserved proteins that are important for antigen presentation, immune response regulation, and cellular housekeeping processes. These proteins can be increased by cellular stress related to pollution, for example, smoke from biomass burning and/or tobacco smoking. Single nucleotide polymorphisms (SNPs) in these genes could affect the levels of their proteins, as well as the susceptibility to developing lung diseases, such as chronic obstructive pulmonary disease (COPD), related to the exposure to environmental factors.

Methods: The subjects included were organized into two comparison groups: 1,103 smokers (COPD patients, COPD-S = 360; smokers without COPD, SWOC = 743) and 442 never-smokers who were chronically exposed to biomass smoke (COPD patients, COPD-BS = 244; exposed without COPD, BBES = 198). Eight SNPs in three HSP genes were selected and genotyped: four in HSPA1A, two in HSPA1B, and two in HSPA1L. Sputum expectoration was induced to obtain pulmonary cells and relative quantification of mRNA expression. Subsequently, the intracellular protein levels of total Hsp27, phosphorylated Hsp27 (Hsp27p), Hsp60, and Hsp70 were measured in a sample of 148 individuals selected based on genotypes.

Results: In the smokers’ group, by a dominant model analysis, we found associations between rs1008438 (CA+AA; p = 0.006, OR = 1.52), rs6457452 (CT+TT; p = 0.000015, OR = 1.99), and rs2763979 (CT+TT; p = 0.007, OR = 1.60) and the risk to COPD. Among those exposed to biomass-burning smoke, only rs1008438 (CA+AA; p < 0.01, OR = 2.84) was associated. Additionally, rs1008438 was associated with disease severity in the COPD-S group (AA; p = 0.02, OR = 2.09). An increase in the relative expression level of HSPA1A was found (12-fold change) in the COPD-BS over the BBES group. Differences in Hsp27 and Hsp60 proteins levels were found (p < 0.05) in the comparison of COPD-S vs. SWOC. Among biomass-burning smoke-exposed subjects, differences in the levels of all proteins (p < 0.05) were detected.

Conclusion: SNPs in HSP genes are associated with the risk of COPD and severe forms of the disease. Differences in the intracellular Hsp levels are altered depending on the exposition source.

17β-estradiol replacement therapy induces eNOS, nNOS and estrogen receptor β in hypophysectomized rats with inflamed footpads

Nitric oxide (NO) plays a key role in inflammation. It is partly produced by three forms of NOS: eNOS of inflammatory cells, nNOS of neural cells and iNOS (inducible isoform). Estrogens can cause an anti-inflammatory effect, although it is not yet clear through which NOS isoforms. The aim of this study was to evaluate the role of the different NOS isoforms, as well as estrogen receptors (ERs) α and β, on the anti-inflammatory effects of estrogens. To avoid the influence of endogenous glucocorticoids or sexual hormones, male rats were hypophysectomized. Animals were segregated into two control groups (no-treatment control group and SHAM-operated animals) and three hypophysectomized groups (no-hormonal treatment, with estradiol-17β, or with testosterone replacement treatment). Freund's complete adjuvant (1 mg) was administered to the footpad of all animals. Measurements were made based on footpad inflammation (with a plethysmometer) such as eNOS, nNOS, iNOS and ER α and β protein expression (by immunohistochemistry principle/method) on days 1, 7 and 14. Only estradiol decreased inflammation, accompanied by increased levels of eNOS and nNOS and differential expression of ERs α and β in the inflammatory infiltrate. The higher levels of estradiol-induced eNOS and nNOS ocurred perhaps through the activation of ER β.

Computational Study of the Binding Modes of Diverse DPN Analogues on Estrogen Receptors (ER) and the Biological Evaluation of a New Potential Antiestrogenic Ligand

Estrogen (17β-estradiol) is essential for normal growth and differentiation in the mammary gland. In the last three decades, previous investigations have revealed that Estrogen Receptor Alpha (ERα) plays a critical role in breast cancer. More recently, observations regarding the widespread expression of ERβ-like proteins in normal and neoplastic mammary tissues have suggested that ERβ is also involved in the mentioned pathology. Design of new drugs both steroidal and nonsteroidal that target any of these receptors represents a promise to treat breast cancer although it remains a challenge due to the sequence similarity between their catalytic domains. In this work, we propose a new set of compounds that could effectively target the estrogen receptors ERα and ERβ. These ligands were designed based on the chemical structure of the ERβ-selective agonist Diarylpropionitrile (DPN). The designed ligands were submitted to in silico ADMET studies, yielding in a filtered list of ligands that showed better drug-like properties. Molecular dynamics simulations of both estrogen receptors and docking analysis were carried-out employing the designed compounds, from which two were chosen due to their promising characteristics retrieved from theoretical results (docking analysis or targeting receptor predictions). They were chemically synthetized and during the process, two precursor ligands were also obtained. These four ligands were subjected to biological studies from which it could be detected that compound mol60b dislplayed inhibitory activity and its ability to activate the transcription via an estrogenic mechanism of action was also determined. Interestinly, this observation can be related to theoretical binding free energy calculations, where the complex: ERβ-mol60b showed the highest energy ΔGbind value in comparison to others.

N-(2'-Hydroxyphenyl)-2-propylpentanamide (OH-VPA), a histone deacetylase inhibitor, induces the release of nuclear HMGB1 and modifies ROS levels in HeLa cells

N-(2'-Hydroxyphenyl)-2-propylpentanamide (OH-VPA) is a valproic acid (VPA) derivative with improved antiproliferative activity toward breast cancer (MCF-7, MDA-MB-231, and SKBr3) and human cervical cancer cell lines (HeLa) compared to that of VPA. However, the pharmacological mechanism of OH-VPA activity remains unknown. High-mobility group box 1 (HMGB1) is an important enzyme that is highly expressed in tumor cells and has a subcellular localization that is dependent on its acetylation or oxidative state. Therefore, in this study, we analyzed changes in HMGB1 sub-cellular localization and reactive oxygen species (ROS) as well as changes in HeLa cell viability in response to treatment with various concentrations of OH-VPA. This compound is formed by the covalent bond coupling VPA to a phenol group, which is capable of acting as a free radical scavenger due to its chemical similarities to quercetin. Our results show that OH-VPA induces nuclear to cytoplasmic translocation of HMGB1, as demonstrated by confocal microscopy observations and infrared spectra that revealed high quantities of acetylated HMGB1 in HeLa cells. Cells treated with 0.8 mM OH-VA exhibited decreased viability and increased ROS levels compared with the lower OH-VPA concentrations tested. Therefore, the antiproliferative mechanism of OH-VPA may be related to histone deacetylase (HDAC) inhibition, as is the case for VPA, which promotes high HMBG1 acetylation, which alters its subcellular localization. In addition, OH-VPA generates an imbalance in cellular ROS levels due to its biochemical activity.

TNF promoter polymorphisms are associated with genetic susceptibility in COPD secondary to tobacco smoking and biomass burning

Background

Smoking and smoke from biomass burning (BB) are the main environmental risk factors for COPD. Clinical differences have been described between COPD related to smoking and related to wood smoke, but no studies have shown genetic differences between patients exposed to these two risk factors.

Methods

To investigate a possible association of tumor necrosis factor (TNF) promoter polymorphisms, we conducted a case–control study. A total of 1,322 subjects were included in four groups: patients with a diagnosis of COPD secondary to smoking (COPD-S, n=384), patients with COPD secondary to biomass burning (COPD-BB, n=168), smokers without COPD (SWOC, n=674), and biomass burning-exposed subjects (BBES n=96). Additionally, a group of 950 Mexican mestizos (MMs) was included as a population control. Three single nucleotide polymorphisms (SNPs) were selected in the TNF gene (rs1800629, rs361525, and rs1800750) and one SNP in the lymphotoxin alpha gene (rs909253).

Results

Statistically significant differences were found with genotype GA of the rs1800629: COPD-S vs SWOC, (p<0.001, odds ratio [OR] =2.55, 95% CI=1.53–4.27); COPD-S vs COPD-BB (p,0.01). When performing the comparison of the less severe (G1: I + II) and the more severe (G2: III + IV) levels, differences were identified in G1 (p<0.05, OR=1.94, 95% CI=1.04–3.63) and G2 (p<0.001, OR=3.68, 95% CI=1.94–3.07) compared with SWOC. Regarding genotype GA of rs361525, it has been associated when comparing COPD-BB vs BBES (p=0.0079, OR=5.99, 95% CI=1.38–53.98).

Conclusion

The heterozygous genotype GA of polymorphisms rs1800629 and rs361525 in the TNF promoter are associated with the risk of COPD.

[Association between IGF system and PAPP-A in coronary atherosclerosis]

Atherosclerosis is a condition that involves multiple pathophysiological mechanisms and whose knowledge has not been fully elucidated. Often, scientific advances on the atherogenic pathophysiology generate that molecules not previously considered in the scene of this disease, were attributed actions on the onset or progression of it. A representative example is the study of a new mechanism involved in the atherogenic process, consisting of the association between the insulin-like growth factor (IGF) system and pregnancy-associated plasma protein-A (PAPP-A). Insulin-like growth factor system is a family of peptides that include 3 peptide hormones, 4 transmembrane receptors and 6 binding proteins. Insulin-like growth factor-1 (IGF-1) is the main ligand of the IGF system involved in coronary atherosclerosis. IGF-1 exerts its effects via activation of the IGF-1R receptor on vascular smooth muscle cells or macrophages. In vascular smooth muscle cells promotes migration and prevents apoptosis which increases plaque stability while in macrophages reduces reverse cholesterol transport leading to the formation of foam cells. Regulation of IGF-1 endothelial bioavailability is carried out by IGFBP proteases, mainly by PAPP-A. In this review, we address the mechanisms between IGF system and PAPP-A in atherosclerosis with emphasis on molecular effects on vascular smooth muscle cells and macrophages.

A review of the proposed role of neutrophils in rodent amebic liver abscess models

Host invasion by Entamoeba histolytica, the pathogenic agent of amebiasis, can lead to the development of amebic liver abscess (ALA). Due to the difficulty of exploring host and amebic factors involved in the pathogenesis of ALA in humans, most studies have been conducted with animal models (e.g., mice, gerbils, and hamsters). Histopathological findings reveal that the chronic phase of ALA in humans corresponds to lytic or liquefactive necrosis, whereas in rodent models there is granulomatous inflammation. However, the use of animal models has provided important information on molecules and mechanisms of the host/parasite interaction. Hence, the present review discusses the possible role of neutrophils in the effector immune response in ALA in rodents. Properly activated neutrophils are probably successful in eliminating amebas through oxidative and non-oxidative mechanisms, including neutrophil degranulation, the generation of free radicals (O₂⁻, H₂O₂, HOCl) and peroxynitrite, the activation of NADPH-oxidase and myeloperoxidase (MPO) enzymes, and the formation of neutrophil extracellular traps (NETs). On the other hand, if amebas are not eliminated in the early stages of infection, they trigger a prolonged and exaggerated inflammatory response that apparently causes ALAs. Genetic differences in animals and humans are likely to be key to a successful host immune response.

Intermittent fasting favored the resolution of Salmonella typhimurium infection in middle-aged BALB/c mice

Intermittent fasting (IF) reportedly increases resistance and intestinal IgA response to Salmonella typhimurium infection in mature mice. The aim of this study was to explore the effect of aging on the aforementioned improved immune response found with IF. Middle-aged male BALB/c mice were submitted to IF or ad libitum (AL) feeding for 40 weeks and then orally infected with S. typhimurium. Thereafter, infected animals were all fed AL (to maximize their viability) until sacrifice on day 7 or 14 post-infection. We evaluated body weight, bacterial load (in feces, Peyer's patches, spleen and liver), total and specific intestinal IgA, lamina propria IgA+ plasma cells, plasma corticosterone, and messenger RNA (mRNA) expression of α-chain, J-chain, and the polymeric immunoglobulin receptor (pIgR) in liver and intestinal mucosa. In comparison with the infected AL counterpart, the infected IF group (long-term IF followed by post-infection AL feeding) generally had lower intestinal and systemic bacterial loads as well as higher total IgA on both post-infection days. Both infected groups showed no differences in corticosterone levels, body weight, or food and caloric intake. The increase in intestinal IgA was associated with enhanced pIgR mRNA expression in the intestine (day 7) and liver. Thus, to maintain body weight and caloric intake, IF elicited metabolic signals that possibly induced the increased hepatic and intestinal pIgR mRNA expression found. The increase in IgA probably resulted from intestinal IgA transcytosis via pIgR. This IgA response along with phagocyte-induced killing of bacteria in systemic organs (not measured) may explain the resolution of the S. typhimurium infection.

The consumption of n-3 polyunsaturated fatty acids differentially modulates gene expression of peroxisome proliferator-activated receptor alpha and gamma and hypoxia-inducible factor 1 alpha in subcutaneous adipose tissue of obese adolescents

The aim of this study was to evaluate the effect of long-chain omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation on metabolic state and gene expression in subcutaneous adipose tissues of obese adolescents. Obese adolescents (n = 26, 10 girls and 16 boys) aged 12.4 ± 2.1 years were assigned to a 12-week regimen of n-3 PUFA intake. Five times per day, subjects received a food supplement consisting of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (3 g per day, 944 mg EPA, and 2,088 mg DHA). Blood parameters were measured, and subcutaneous adipose tissue biopsies were analyzed to determine gene expression at baseline and after 12 weeks. Student's t test and the Wilcoxon signed-rank test were used to estimate differences in arithmetic means of pre- and post-dietary supplementation for various anthropometric, biochemical, clinical, and gene expression parameters. After 12 weeks, n-3 PUFA consumption was associated with decreased body mass index (29.7 ± 4.6 vs. 27.8 ± 4.4 kg/m(2); P < 0.001), waist circumference (93.2 ± 9.9 vs. 90.5 ± 10.0 cm; P < 0.003), hip circumference (102.9 ± 10.9 vs. 101.1 ± 10.9 cm; P < 0.014), and blood triglyceride levels (220.8 ± 27.4 vs. 99.7 ± 32.7 mg/dL; P < 0.001). Fatty acid supplementation/n3 PUFA supplementation was associated with a downregulated expression of the genes encoding PPARγ and PGC-1α (P < 0.001), and an upregulated expression of the genes encoding PPARα (P < 0.007) and SREBP1 (P < 0.021). The expressions of SOD2 (P < 0.04), CAT (P < 0.001), GPX3 (P < 0.032) and HIF-1α protein also decreased. Our study demonstrated that n-3 PUFA consumption and dietary restriction improved the anthropometric parameters and decreased the triglycerides levels of the adolescents, suggesting a reduction in hypoxia in subcutaneous adipose tissue.

Stress modulates intestinal secretory immunoglobulin A

Stress is a response of the central nervous system to environmental stimuli perceived as a threat to homeostasis. The stress response triggers the generation of neurotransmitters and hormones from the hypothalamus pituitary adrenal axis, sympathetic axis and brain gut axis, and in this way modulates the intestinal immune system. The effects of psychological stress on intestinal immunity have been investigated mostly with the restraint/immobilization rodent model, resulting in an up or down modulation of SIgA levels depending on the intensity and time of exposure to stress. SIgA is a protein complex formed by dimeric (dIgA) or polymeric IgA (pIgA) and the secretory component (SC), a peptide derived from the polymeric immunoglobulin receptor (pIgR). The latter receptor is a transmembrane protein expressed on the basolateral side of gut epithelial cells, where it uptakes dIgA or pIgA released by plasma cells in the lamina propria. As a result, the IgA-pIgR complex is formed and transported by vesicles to the apical side of epithelial cells. pIgR is then cleaved to release SIgA into the luminal secretions of gut. Down modulation of SIgA associated with stress can have negative repercussions on intestinal function and integrity. This can take the form of increased adhesion of pathogenic agents to the intestinal epithelium and/or an altered balance of inflammation leading to greater intestinal permeability. Most studies on the molecular and biochemical mechanisms involved in the stress response have focused on systemic immunity. The present review analyzes the impact of stress (mostly by restraint/immobilization, but also with mention of other models) on the generation of SIgA, pIgR and other humoral and cellular components involved in the intestinal immune response. Insights into these mechanisms could lead to better therapies for protecting against pathogenic agents and avoiding epithelial tissue damage by modulating intestinal inflammation.

Purification and cellular localization of the Entamoeba histolytica transcarboxylase

Genome analysis of Entamoeba histolytica predicts the presence of acetyl-CoA carboxylase. Using Western blot, histochemistry, and confocal microscopy, we demonstrated the presence of a biotin-containing protein in the cytoplasm of E. histolytica, with a molecular weight of 136 kDa and biotin-carboxylase activity. This protein probably corresponds to a transcarboxylase that catalyzes the rate-limiting reaction leading to fatty acid elongation.

Repeated restraint stress reduces the number of IgA-producing cells in Peyer's patches

The few reports that have analyzed the effects of stress on the immune cells of the intestinal mucosa or the functions of these cells have tended to focus on S-IgA levels in saliva, and these studies have shown contradictory results. The principal objective of this study was to analyze the effects of repeated restraint stress on the number and distribution of immune cells in Peyer's patches (PPs) as well as the effects of glucocorticoid and catecholamine administration on the same stress-related parameters. Upon analyzing the effect of repeated restraint stress on PPs, it was found that there was no modification in the morphological structure of the PPs but that restraint stress reduced the total number of lymphocytes and the number of CD8+ T cells, B cells, and plasma cells in PPs. Only at the site of PPs where IgA-producing plasma cells are most numerous (the dome) was a decrease found in this type of cell. These effects were due at least in part to the effect of glucocorticoids and catecholamines. Since IgA produced in PPs is a natural antibody that impedes bacterial infections, repeated stress may favor the entry of pathogens through the intestine.

Mycobacterium tuberculosis virulence correlates with mitochondrial cytochrome c release in infected macrophages

Mitochondria are at the centre of molecular events involved in energy production, cell survival and apoptosis. Mitochondrial membrane potential (Deltapsim) is maintained by cellular catabolic reactions and the electron transport chain of which cytochrome c is a constituent, whereas the proton leak pathway, ATP synthesis and turnover consume it. Mitochondrial alterations such as a drop in Deltapsim, swelling and cytochrome c release have been observed in apoptosis. However, there is a paucity of information concerning mitochondrial function in the course of intracellular infections, a process that must certainly induce stress on the host cell. This work analyses the effect that two strains of mycobacteria of opposing virulence have on the mitochondria of murine macrophages in the early stages of infection. It was found that infection of J774 cells with both Mycobacterium tuberculosis H37Ra and M. tuberculosis H37Rv readily induced changes in Deltapsim as well as in mitochondrial morphology at the ultrastructural level. In addition, an increase in cytosolic ATP was found at 24 h post infection with both strains of M. tuberculosis. Interestingly, only M. tuberculosis H37Rv was able to induce cytochrome c release from mitochondria to the cytosol, thus suggesting the occurrence in M. tuberculosis H37Rv of a specific factor(s) capable of regulating cytochrome c translocation. The precise role of cytochrome c release in the context of a mycobacterial infection remains to be elucidated.