Variants in proinflammatory genes IL1RL1, IL1B and IRF4 are associated with overweight in a pediatric Brazilian population

Genome-wide association study on overweight in Brazilian children with asthma: Old stories and new discoveries

INTRODUCTION

Overweight and obesity are chronic and multifactorial diseases with a strong genetic component contributing to weight gain across all age groups. This study aimed to conduct a Genome-wide Association Study (GWAS) on a cohort of 1,004 Brazilian children (5-11 years old) to identify specific DNA regions associated with susceptibility to overweight.

METHODS

The GWAS was performed on children participating in the SCAALA (Asthma and Allergy Social Changes in Latin America) program, with participants classified as either overweight or non-overweight. Genotyping was carried out using the Illumina 2.5 Human Omni bead chip. Using ELISA, cytokine levels (IL-5, IL-13, IL-10, and IFN) were measured in the blood culture supernatant. Furthermore, pathway analyses were conducted utilizing the Gene Ontology tool.

RESULTS

Our analysis revealed eight significant signals distributed across the genome. The most prominent single nucleotide variant (SNV) was identified in the IL1R1 gene, followed by three variants in the LOC105377841 region (located between the ADH5P4 and EYS genes), as well as variants in the KNTC1, RAPTOR, and DSCAM genes. Among the identified variants, three (IL1R1, RAPTOR, and DSCAM) are associated with immune mechanisms, one (ST18) is linked to the death pathway, and one (KNTC1) is associated with mitotic spindle assembly. The genetic risk score analysis demonstrated that having one or more variants among the six analyzed significantly increased the risk of being overweight by eightfold.

CONCLUSIONS

Our study uncovered genetic loci within pathways with strong biological plausibility, including identifying a novel region (LOC105377841) not previously associated with overweight. Understanding the genetic variants involved in overweight and obesity is crucial for advancing our knowledge of these diseases, particularly within mixed populations such as the Brazilian population.

Toxic effect and mRNA mechanism of moon dust simulant induced pulmonary inflammation in rats

Moon dust presents a significant hazard to manned moon exploration missions, yet our understanding of its toxicity remains limited. The objective of this study is to investigate the pattern and mechanism of lung inflammation induced by subacute exposure to moon dust simulants (MDS) in rats. SD rats were exposed to MDS and silica dioxide through oral and nasal inhalation for 6 hours per day continuously for 15 days. Pathological analysis indicated that the toxicity of MDS was lower than that of silica dioxide. MDS led to a notable recruitment and infiltration of macrophages in the rat lungs. Material characterization and biochemical analysis revealed that SiO2, Fe2O3, and TiO2 could be crucial sources of MDS toxicity. The study revealed that MDS-induced oxidative stress response can lead to pulmonary inflammation, which potentially may progress to lung fibrosis. Transcriptome sequencing revealed that MDS suppresses the PI3K-AKT signaling pathway, triggers the Tnfr2 non-classical NF-kB pathway and IL-17 signaling pathway, ultimately causing lung inflammation and activating predominantly antioxidant immune responses. Moreover, the study identified the involvement of upregulated genes IL1b, csf2, and Sod2 in regulating immune responses in rat lungs, making them potential key targets for preventing pulmonary toxicity related to moon dust exposure. These findings are expected to aid in safeguarding astronauts against the hazardous effects of moon dust and offer fresh insights into the implications and mechanisms of moon dust toxicity.

Immunogenetic Aspects of Sarcopenic Obesity

Sarcopenic obesity (SO) is a combination of obesity and sarcopenia, with diagnostic criteria defined as impaired skeletal muscle function and altered body composition (e.g., increased fat mass and reduced muscle mass). The mechanism of SO is not yet perfectly understood; however, the pathogenesis includes aging and its complications, chronic inflammation, insulin resistance (IR), and hormonal changes. Genetic background is apparent in the pathogenesis of isolated obesity, which is most often polygenic and is characterized by the additive effect of various genetic factors. The genetic etiology has not been strictly established in SO. Still, many data confirm the existence of pathogenic gene variants, e.g., Fat Mass and Obesity Associated Gene (FTO), beta-2-adrenergic receptor (ADRB2) gene, melanocortin-4 receptor (MC4R) and others with obesity. The literature on the role of these genes is scarce, and their role has not yet been thoroughly established. On the other hand, the involvement of systemic inflammation due to increased adipose tissue in SO plays a significant role in its pathophysiology through the synthesis of various cytokines such as monocyte chemoattractant protein-1 (MCP-1), IL-1Ra, IL-15, adiponectin or CRP. The lack of anti-inflammatory cytokine (e.g., IL-15) can increase SO risk, but further studies are needed to evaluate the exact mechanisms of implications of various cytokines in SO individuals. This manuscript analyses various immunogenetic and non-genetic factors and summarizes the recent findings on immunogenetics potentially impacting SO development.