Obesity-induced downregulation of miR-192 exacerbates lipopolysaccharide-induced acute lung injury by promoting macrophage activation.

BACKGROUND: Macrophage activation may play a crucial role in the increased susceptibility of obese individuals to acute lung injury (ALI). Dysregulation of miRNA, which is involved in various inflammatory diseases, is often observed in obesity. This study aimed to investigate the role of miR-192 in lipopolysaccharide (LPS)-induced ALI in obese mice and its mechanism of dysregulation in obesity. METHODS: Human lung tissues were obtained from obese patients (BMI ≥ 30.0 kg/m2) and control patients (BMI 18.5-24.9 kg/m2). An obese mouse model was established by feeding a high-fat diet (HFD), followed by intratracheal instillation of LPS to induce ALI. Pulmonary macrophages of obese mice were depleted through intratracheal instillation of clodronate liposomes. The expression of miR-192 was examined in lung tissues, primary alveolar macrophages (AMs), and the mouse alveolar macrophage cell line (MH-S) using RT-qPCR. m6A quantification and RIP assays helped determine the cause of miR-192 dysregulation. miR-192 agomir and antagomir were used to investigate its function in mice and MH-S cells. Bioinformatics and dual-luciferase reporter gene assays were used to explore the downstream targets of miR-192. RESULTS: In obese mice, depletion of macrophages significantly alleviated lung tissue inflammation and injury, regardless of LPS challenge. miR-192 expression in lung tissues and alveolar macrophages was diminished during obesity and further decreased with LPS stimulation. Obesity-induced overexpression of FTO decreased the m6A modification of pri-miR-192, inhibiting the generation of miR-192. In vitro, inhibition of miR-192 enhanced LPS-induced polarization of M1 macrophages and activation of the AKT/ NF-κB inflammatory pathway, while overexpression of miR-192 suppressed these reactions. BIG1 was confirmed as a target gene of miR-192, and its overexpression offset the protective effects of miR-192. In vivo, when miR-192 was overexpressed in obese mice, the activation of pulmonary macrophages and the extent of lung injury were significantly improved upon LPS challenge. CONCLUSIONS: Our study indicates that obesity-induced downregulation of miR-192 expression exacerbates LPS-induced ALI by promoting macrophage activation. Targeting macrophages and miR-192 may provide new therapeutic avenues for obesity-associated ALI.

[Assessment of the sufficiency of Moscow population with folic acid, depending on the combined effect of polymorphism of MTHFR and FTO genes].

The results of assessing the sufficiency of folic acid of the residents of the Moscow region have been presented depending on rs1801133 MTHFR gene polymorphism and rs9939609 FTO gene polymorphism. A total of 326 people were examined, including 74 men and 252 women aged 20 to 65 years. The results of determining the level of folic acid in blood serum showed insufficiency of this vitamin among the population of the Moscow region of the Russian Federation. The expressed vitamin deficit (level <3,0 ng/ml) was detected in 24.2% of the surveyed residents, in 22.8% folic acid level was at the lower bound of the norm (3.0-4.5 ng/ml). The results of genotyping showed a statistically significant association of low folic acid level with rs1801133 MTHFR gene polymorphism in carriers of A allele of rs9939609 FTO gene polymorphism both in the homozygous state (genotype AA) and in the heterozygous (genotype AT) state, OR=4.26; CI (1.40-12.9), p=0.008, as well as with rs9939609 FTO gene polymorphism in carriers of the T allele of rs1801133 MTHFR gene polymorphism both in the homozygous (genotype TT) and heterozygous (CT genotype) state, OR=3.29; CI (1.07-10.1), p=0.03. In carriers of 3 alleles of risk of folic acid deficiency [rs9939609 FTO gene polymorphism and rs1801133 MTHFR gene polymorphism (genotypes CT/AA and TT/AT)] blood serum level of folic acid was below the norm, that indicated folate deficiency in this category of persons.