Tropheryma whipplei, the Whipple's disease bacillus, induces macrophage apoptosis through the extrinsic pathway

Tropheryma whipplei, the etiological agent of Whipple's disease, is an intracellular bacterium that infects macrophages. We previously showed that infection of macrophages results in M2 polarization associated with induction of apoptosis and interleukin (IL)-16 secretion. In patients with Whipple's disease, circulating levels of apoptotic markers and IL-16 are increased and correlate with the activity of the disease. To gain insight into the understanding of the pathophysiology of this rare disease, we examined the molecular pathways involved in T. whipplei-induced apoptosis of human macrophages. Our data showed that apoptosis induction depended on bacterial viability and inhibition of bacterial protein synthesis reduced the apoptotic program elicited by T. whipplei. Induction of apoptosis was also associated with a massive degradation of both pro- and anti-apoptotic mediators. Caspase-specific inhibition experiments revealed that initiator caspases 8 and 10 were required for apoptosis, in contrast to caspases 2 and 9, in spite of cytochrome-c release from mitochondria. Finally, the effector caspases 3 and 6 were mandatory for apoptosis induction. Collectively, these data suggest that T. whipplei induces apoptosis through the extrinsic pathway and that, beside M2 polarization of macrophages, apoptosis induction contributes to bacterial replication and represents a virulence trait of this intracellular pathogen

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

Abstract 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

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

Juan Manuel Reséndiz-Hernández,1 Enrique Ambrocio-Ortiz,1 Gloria Pérez-Rubio,1 Luis Alberto López-Flores,1 Edgar Abarca-Rojano,2 Gandhi Fernando Pavón-Romero,3 Fernando Flores-Trujillo,4 Rafael de Jesús Hernández-Zenteno,4 Ángel Camarena,1 Martha Pérez-Rodríguez,5 Ana María Salazar,6 Alejandra Ramírez-Venegas,4 Ramcés Falfán-Valencia1 1HLA Laboratory, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico; 2Research and Graduate Studies Section, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico; 3Department of Allergy and Clinical Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico; 4Tobacco Smoking and COPD Research Department, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico; 5Unit of Medical Research in Immunology, CMN S-XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico; 6Department of Genomic Medicine and Environmental Toxicology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico 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. Keywords: COPD, biomass burning, SNP, TN