Differential Expression of Immune Response Genes in Asymptomatic Chronic Chagas Disease Patients Versus Healthy Subjects

Infection by the Trypanosoma cruzi parasite causes Chagas disease and triggers multiple immune mechanisms in the host to combat the pathogen. Chagas disease has a variable clinical presentation and progression, producing in the chronic phase a fragile balance between the host immune response and parasite replication that keeps patients in a clinically silent asymptomatic stage for years. Since the parasite is intracellular and replicates within cells, the cell-mediated response of the host adaptive immunity plays a critical role. This function is mainly orchestrated by T lymphocytes, which recognize parasite antigens and promote specific functions to control the infection. However, little is known about the immunological markers associated with this asymptomatic stage of the disease. In this large-scale analysis, the differential expression of 106 immune system-related genes has been analyzed using high-throughput qPCR in T. cruzi antigen-stimulated PBMC from chronic Chagas disease patients with indeterminate form (IND) and healthy donors (HD) from endemic and non-endemic areas of Chagas disease. This analysis revealed that there were no differences in the expression level of most genes under study between healthy donors from endemic and non-endemic areas determined by PCA and differential gene expression analysis. Instead, PCA revealed the existence of different expression profiles between IND patients and HD (p < 0.0001), dependent on the 32 genes included in PC1. Differential gene expression analysis also revealed 23 upregulated genes (expression fold change > 2) and 11 downregulated genes (expression fold change < 0.5) in IND patients versus HD. Enrichment analysis showed that several upregulated genes in IND patients participate in relevant immunological pathways such as antigen-dependent B cell activation, stress induction of HSP regulation, NO2-dependent IL12 pathway in NK cells, and cytokine-inflammatory response. The antigen-specific differential gene expression profile detected in these patients and the relevant immunological pathways that seem to be activated could represent potential biomarkers of the asymptomatic form of Chagas disease, helpful to diagnosis and infection control.

Early Transcriptional Liver Signatures in Experimental Visceral Leishmaniasis

Transcriptional analysis of complex biological scenarios has been used extensively, even though sometimes the results of such analysis may prove imprecise or difficult to interpret due to an overwhelming amount of information. In this study, a large-scale real-time qPCR experiment was coupled to multivariate statistical analysis in order to describe the main immunological events underlying the early L. infantum infection in livers of BALB/c mice. High-throughput qPCR was used to evaluate the expression of 223 genes related to immunological response and metabolism 1, 3, 5, and 10 days post infection. This integrative analysis showed strikingly different gene signatures at 1 and 10 days post infection, revealing the progression of infection in the experimental model based on the upregulation of particular immunological response patterns and mediators. The gene signature 1 day post infection was not only characterized by the upregulation of mediators involved in interferon signaling and cell chemotaxis, but also the upregulation of some inhibitory markers. In contrast, at 10 days post infection, the upregulation of many inflammatory and Th1 markers characterized a more defined gene signature with the upregulation of mediators in the IL-12 signaling pathway. Our results reveal a significant connection between the expression of innate immune response and metabolic and inhibitory markers in early L. infantum infection of the liver.

Impact of Differentiated Macrophage-Like Cells on the Transcriptional Toxicity Profile of CuO Nanoparticles in Co-Cultured Lung Epithelial Cells

To mimic more realistic lung tissue conditions, co-cultures of epithelial and immune cells are one comparatively easy-to-use option. To reveal the impact of immune cells on the mode of action (MoA) of CuO nanoparticles (NP) on epithelial cells, A549 cells as a model for epithelial cells have been cultured with or without differentiated THP-1 cells, as a model for macrophages. After 24 h of submerged incubation, cytotoxicity and transcriptional toxicity profiles were obtained and compared between the cell culture systems. Dose-dependent cytotoxicity was apparent starting from 8.0 µg/cm² CuO NP. With regard to gene expression profiles, no differences between the cell models were observed concerning metal homeostasis, oxidative stress, and DNA damage, confirming the known MoA of CuO NP, i.e., endocytotic particle uptake, intracellular particle dissolution within lysosomes with subsequent metal ion deliberation, increased oxidative stress, and genotoxicity. However, applying a co-culture of epithelial and macrophage-like cells, CuO NP additionally provoked a pro-inflammatory response involving NLRP3 inflammasome and pro-inflammatory transcription factor activation. This study demonstrates that the application of this easy-to-use advanced in vitro model is able to extend the detection of cellular effects provoked by nanomaterials by an immunological response and emphasizes the use of such models to address a more comprehensive MoA.

Impact of Endocytosis and Lysosomal Acidification on the Toxicity of Copper Oxide Nano- and Microsized Particles: Uptake and Gene Expression Related to Oxidative Stress and the DNA Damage Response

The toxicity of the copper oxide nanoparticles (CuO NP) has been attributed to the so-called "Trojan horse"-type mechanism, relying on the particle uptake and extensive intracellular release of copper ions, due to acidic pH in the lysosomes. Nevertheless, a clear distinction between extra- and intracellular-mediated effects is still missing. Therefore, the impact of the endocytosis inhibitor hydroxy-dynasore (OH-dyn), as well as bafilomycin A1 (bafA1), inhibiting the vacuolar type H⁺-ATPase (V-ATPase), on the cellular toxicity of nano- and microsized CuO particles, was investigated in BEAS 2 B cells. Selected endpoints were cytotoxicity, copper uptake, glutathione (GSH) levels, and the transcriptional DNA damage and (oxidative) stress response using the high-throughput reverse transcription quantitative polymerase chain reaction (RT-qPCR). OH-dyn markedly reduced intracellular copper accumulation in the cases of CuO NP and CuO MP; the modulation of gene expression, induced by both particle types affecting especially HMOX1, HSPA1A, MT1X, SCL30A1, IL8 and GADD45A, were completely abolished. BafA1 lowered the intracellular copper concentration in case of CuO NP and strongly reduced transcriptional changes, while any CuO MP-mediated effects were not affected by bafA1. In conclusion, the toxicity of CuO NP depended almost exclusively upon dynamin-dependent endocytosis and the intracellular release of redox-active copper ions due to lysosomal acidification, while particle interactions with cellular membranes appeared to be not relevant.

Pigs are useful for the molecular study of bone inflammation and regeneration in humans

Pigs are used with increased frequency to model different kinds of orthopedic surgical conditions. In order to show the full potential of porcine models in orthopedic research, it is therefore required to examine the expression of bone regulatory genes in pigs affected by orthopedic surgery and compare it to the expression in humans and mice as mice, are one of the most applied animal species in orthopedics today. In the present study, the local molecular response to drilling of a tibial implant cavity, and the subsequent insertion of a steel implant was examined in a porcine model. Pigs were euthanized five days after drilling of the bone. The molecular response of 73 different genes was analyzed using a high-throughput quantitative polymerase chain reaction platform and compared to histopathology. Histologically, it was found that bone remodeling was initiated on day 5 after surgery and was associated with upregulation of several genes involved in bone degradation and formation ( CTSK, ACP5, IBSP, RANK, RANKL and COL1A1). Interleukin-6 and several acute-phase proteins (C3, SAA and ITIH4) were significantly upregulated, indicating their importance in the initial process of healing and osseointegration. All tested bone morphogenic proteins (BMP2, -4 and -7) including their inhibitor noggin were also significantly upregulated. Surprisingly, vascular endothelial growth factor A was not found to be regulated five days after surgery while several other vascular growth factors (ANGPT1, ANGPT2 and PTN) were upregulated. The pig was found to be a useful model for elucidation of bone regulatory genes in humans.