Association of caspase-1 polymorphisms with Chagas cardiomyopathy among individuals in Santa Cruz, Bolivia

Cytokine Networks as Targets for Preventing and Controlling Chagas Heart Disease

Chagas disease, a neglected disease caused by the protozoan Trypanosoma cruzi, is endemic in 21 Latin American countries, affecting 6-8 million people. Increasing numbers of Chagas disease cases have also been reported in non-endemic countries due to migration, contamination via blood transfusions or organ transplantation, characterizing Chagas as an emerging disease in such regions. While most individuals in the chronic phase of Chagas disease remain in an asymptomatic clinical form named indeterminate, approximately 30% of the patients develop a cardiomyopathy that is amongst the deadliest cardiopathies known. The clinical distinctions between the indeterminate and the cardiac clinical forms are associated with different immune responses mediated by innate and adaptive cells. In this review, we present a collection of studies focusing on the human disease, discussing several aspects that demonstrate the association between chemokines, cytokines, and cytotoxic molecules with the distinct clinical outcomes of human infection with Trypanosoma cruzi. In addition, we discuss the role of gene polymorphisms in the transcriptional control of these immunoregulatory molecules. Finally, we discuss the potential application of cytokine expression and gene polymorphisms as markers of susceptibility to developing the severe form of Chagas disease, and as targets for disease control.

CASP1 Gene Polymorphisms and BAT1-NFKBIL-LTA-CASP1 Gene-Gene Interactions Are Associated with Restenosis after Coronary Stenting

In the present study, we evaluated the association of the BAT1, NFKBIL, LTA, and CASP1 single nucleotide polymorphisms and the gene−gene interactions with risk of developing restenosis after coronary stenting. The allele and genotype determination of the polymorphisms (BAT1 rs2239527 C/G, NFKBIL1 rs2071592 T/A, LTA rs1800683 G/A, CASP1 rs501192 A/G, and CASP1 rs580253 A/G) were performed by 5’exonuclease TaqMan assays in 219 patients: 66 patients with restenosis and 153 without restenosis. The distribution of rs2239527 C/G, rs2071592 T/A, and rs1800683 G/A polymorphisms was similar in patients with and without restenosis. Nonetheless, under recessive (OR = 2.73, pCRes = 0.031) and additive models (OR = 1.65, pCAdd = 0.039), the AA genotype of the rs501192 A/G polymorphism increased the restenosis risk. Under co-dominant, dominant, recessive, and additive models, the AA genotype of the rs580253 A/G was associated with a high restenosis risk (OR = 5.38, pCCo-Dom = 0.003; OR = 2.12, pCDom = 0.031; OR = 4.32, pCRes = 0.001; and OR = 2.16, 95%CI: 1.33−3.52, pCAdd = 0.001, respectively). In addition, we identified an interaction associated with restenosis susceptibility: BAT1-NFKBIL1-LTA-CASP1 (OR = 9.92, p < 0.001). In summary, our findings demonstrate that the rs501192 A/G and rs580253 A/G polymorphisms, as well as the gene−gene interactions between BAT1-NFKBIL1-LTA-CASP1, are associated with an increased restenosis risk after coronary stenting.

Identification of Differentially Methylated CpG Sites in Fibroblasts from Keloid Scars

As a part of an abnormal healing process of dermal injuries and irritation, keloid scars arise on the skin as benign fibroproliferative tumors. Although the etiology of keloid scarring remains unsettled, considerable recent evidence suggested that keloidogenesis may be driven by epigenetic changes, particularly, DNA methylation. Therefore, genome-wide scanning of methylated cytosine-phosphoguanine (CpG) sites in extracted DNA from 12 keloid scar fibroblasts (KF) and 12 control skin fibroblasts (CF) (six normal skin fibroblasts and six normotrophic fibroblasts) was conducted using the Illumina Human Methylation 450K BeadChip in two replicates for each sample. Comparing KF and CF used a Linear Models for Microarray Data (Limma) model revealed 100,000 differentially methylated (DM) CpG sites, 20,695 of which were found to be hypomethylated and 79,305 were hypermethylated. The top DM CpG sites were associated with TNKS2, FAM45B, LOC723972, GAS7, RHBDD2 and CAMKK1. Subsequently, the most functionally enriched genes with the top 100 DM CpG sites were significantly (p ≤ 0.05) associated with SH2 domain binding, regulation of transcription, DNA-templated, nucleus, positive regulation of protein targeting to mitochondrion, nucleoplasm, Swr1 complex, histone exchange, and cellular response to organic substance. In addition, NLK, CAMKK1, LPAR2, CASP1, and NHS showed to be the most common regulators in the signaling network analysis. Taken together, these findings shed light on the methylation status of keloids that could be implicated in the underlying mechanism of keloid scars formation and remission.

Inflammasome genetics and complex diseases: a comprehensive review

The inflammasome is a cytoplasmic multiprotein complex responsible for the activation of inflammatory caspases (caspase-1, -4, and -5) in response to pathogen- and/or damage-associated molecular patterns or to homeostasis-altering molecular pathways, and for the consequent release of the pro-inflammatory cytokines interleukin (IL)-1ß and IL-18. Taking in account the complexity of inflammasome activation and that several regulatory steps are involved in maintaining its physiologic role in homeostasis and innate immune response, it does not surprise that several genetic variants in inflammasome components have been associated with common pathologies in the general population, such as autoimmune disorders, cardiovascular diseases, obesity and associated metabolic syndrome, neurodegenerative diseases, and cancer. Moreover, the susceptibility to infectious agents and/or to develop severe complications during infections also has been related to inflammasome genetics. In this work, we revised genetic association studies about polymorphisms of main inflammasome genes in sterile as well as infectious diseases, trying to depict the genetic contribution of inflammasome in disease pathogenesis.

MicroRNA‑186‑5p is expressed highly in ethanol‑induced cardiomyocytes and regulates apoptosis via the target gene XIAP

Ethanol has a toxic effect on the heart, resulting in cardiomyocyte damage. Long-term high intake of ethanol leads to a non-ischemic dilated cardiomyopathy termed alcoholic cardiomyopathy (ACM). However, the pathogenesis of alcoholic cardiomyopathy remains unclear. The apoptosis of cardiomyocytes serves an important role in the pathogenesis of ACM. X-linked inhibitor of apoptosis protein (XIAP) is an important anti-apoptotic protein in human tissue cells. To the best of our knowledge, no studies have reported on its function in ethanol-induced cardiomyopathy. Previous works have screened the ACM-associated differentially expressed microRNAs (miRs), including miR-186-5p and miR-488-3p. TargetScan bioinformatics software was used to predict 949 target genes associated with miR-186-5p, and XIAP was demonstrated to be a target of miR-186-5p. The present study firstly analyzed the levels of apoptosis in ethanol-treated cardiomyocytes using flow cytometry. Alterations in the expression levels of miR-186-5p and XIAP were subsequently evaluated in ethanol-treated AC16 cardiomyocytes to assess the specific molecular mechanisms of ethanol-induced cardiomyocyte apoptosis. The levels of apoptosis in AC16 cardiomyocytes increased following ethanol treatment, and further increased with the rise in concentration and action time of ethanol. The expression levels of miR-186-5p were upregulated, and the expression levels of XIAP were downregulated in ethanol-treated cardiomyocytes. miR-186-5p may regulate ethanol-induced apoptosis in cardiomyocytes using XIAP as the direct target gene. This study provides a novel therapeutic target for the prevention and treatment of ACM.

Improved DNA extraction technique from clot for the diagnosis of Chagas disease

Background

The detection of Trypanosoma cruzi genetic material in clinical samples is considered an important diagnostic tool for Chagas disease. We have previously demonstrated that PCR using clot samples yields greater sensitivity than either buffy coat or whole blood samples. However, phenol-chloroform DNA extraction from clot samples is difficult and toxic. The objective of the present study was to improve and develop a more sensitive method to recover parasite DNA from clot samples for the diagnosis of Chagas disease.

Methodology/Principal findings

A total of 265 match pair samples of whole blood–guanidine (GEB) and clot samples were analyzed; 150 were from Chagas seropositive subjects. DNA was extracted from both whole blood-guanidine samples, using a previously standardized methodology, and from clot samples, using a newly developed methodology based on a combination of the FastPrep technique and the standard method for GEB extraction. A qPCR targeting the nuclear satellite sequences was used to compare the sample source and the extraction method. Of the 150 samples from Chagas positive individuals by serology, 47 samples tested positive by qPCR with DNA extracted by both GEB and clot, but an additional 13 samples tested positive only in DNA extracted from clot. No serology-negative samples resulted positive when tested by qPCR.

Conclusions

The new methodology for DNA extraction from clot samples improves the molecular diagnosis of Chagas disease.

Detection of nucleic acid has become an important tool for the diagnosis of Chagas disease. Whole blood samples are usually the source of DNA and qPCR the preferred technique to demonstrate the presence of T. cruzi DNA. Although DNA extracted from clot samples has shown higher sensitivity than from whole blood, DNA extraction is performed using phenol-chloroform, which has biohazard issues. We theorize that a clot traps parasites, making it a better source of DNA for Chagas diagnosis using PCR. The present study describes a new DNA extraction methodology from clot samples which avoids the use of phenol-chloroform. The new methodology was compared to the internationally standardized diagnostic method, which is based on extraction of DNA from whole blood preserved with guanidine EDTA and a commercial kit.