Increased Expression of sST2 in Early HIV Infected Patients Attenuated the IL-33 Induced T Cell Responses

Inflammasome Genetic Variants Are Associated with Protection to Clinical Severity of COVID-19 among Patients from Rio de Janeiro, Brazil

COVID-19 has a broad spectrum of clinical manifestations, from asymptomatic or mild/moderate symptoms to severe symptoms and death. The mechanisms underlying its clinical evolution are still unclear. Upon SARS-CoV-2 infection, host factors, such as the inflammasome system, are activated by the presence of the virus inside host cells. The search for COVID-19 risk factors is of relevance for clinical management. In this study, we investigated the impact of inflammasome single-nucleotide polymorphisms (SNPs) in SARS-CoV-2-infected individuals with distinct severity profiles at clinical presentation. Patients were divided into two groups according to disease severity at clinical presentation based on the WHO Clinical Progression Scale. Group 1 included patients with mild/moderate disease (WHO < 6; n = 76), and group 2 included patients with severe/critical COVID-19 (WHO ≥ 6; n = 357). Inpatients with moderate to severe/critical profiles were recruited and followed-up at Hospital Center for COVID-19 Pandemic – National Institute of Infectology (INI)/FIOCRUZ, RJ, Brazil, from June 2020 to March 2021. Patients with mild disease were recruited at Oswaldo Cruz Institute (IOC)/FIOCRUZ, RJ, Brazil, in August 2020. Genotyping of 11 inflammasome SNPs was determined by real-time PCR. Protection and risk estimation were performed using unconditional logistic regression models. Significant differences in NLRP3 rs1539019 and CARD8 rs2043211 were observed between the two groups. Protection against disease severity was associated with the A/A genotype (OR_adj = 0.36; P = 0.032), allele A (OR_adj = 0.93; P = 0.010), or carrier-A (OR_adj = 0.45; P = 0.027) in the NLRP3 rs1539019 polymorphism; A/T genotype (OR_adj = 0.5; P = 0.045), allele T (OR_adj = 0.93; P = 0.018), or carrier-T (OR_adj = 0.48; P = 0.029) in the CARD8 rs2043211 polymorphism; and the A-C-G-C-C (OR_adj = 0.11; P = 0.018), A-C-G-C-G (OR_adj = 0.23; P = 0.003), C-C-G-C-C (OR_adj = 0.37; P = 0.021), and C-T-G-A-C (OR_adj = 0.04; P = 0.0473) in NLRP3 genetic haplotype variants. No significant associations were observed for the other polymorphisms. To the best of our knowledge, this is the first study demonstrating an association between CARD8 and NLRP3 inflammasome genetic variants and protection against COVID-19 severity, contributing to the discussion of the impact of inflammasomes on COVID-19 outcomes.

Human Immunodeficiency Virus-Associated Myocardial Diastolic Dysfunction and Soluble ST2 Concentration in Tanzanian Adults: A Cross-Sectional Study

BACKGROUND

The aims of this study were (1) to compare the prevalence of myocardial diastolic dysfunction (DD) in antiretroviral therapy (ART)-naive people living with human immunodeficiency virus (PLWH) to human immunodeficiency virus (HIV)-uninfected adults in East Africa and (2) to determine the association between serum concentration of the cardiac biomarkers ST2 and DD.

METHODS

In this cross-sectional study, we enrolled PLWH and uninfected adults at a referral HIV clinic in Mwanza, Tanzania. Standardized history, echocardiography, and serum were obtained. Regression models were used to quantify associations.

RESULTS

We enrolled 388 ART-naive PLWH and 461 HIV-uninfected adults with an average age of 36.0 ± 10.2 years. Of PLWH in the third, fourth, and fifth decades of life, 5.0%, 12.5%, and 32.7%, respectively, had DD. PLWH had a higher prevalence of DD (adjusted odds ratio, 2.71 [95% confidence interval, 1.62-4.55]; P < .0001). PLWH also had a higher probability of dysfunction with one or fewer traditional risk factors present. Serum ST2 concentration was associated with dysfunction in PLWH but not uninfected participants (P = .04 and P = .90, respectively).

CONCLUSIONS

In a large population of young adults in sub-Saharan Africa, DD prevalence increased starting in the third decade of life. HIV was independently associated with dysfunction. Serum ST2 concentration was associated with DD in PLWH but not HIV-uninfected participants. This pathway may provide insight into the mechanisms of HIV-associated dysfunction.

The Functional Roles of IL-33/ST2 Axis in Ocular Diseases

Interleukin-33 (IL-33), an important member of the IL-1 family, plays a pivotal role in regulating immune responses via combining with its receptor suppression of tumorigenicity 2 (ST2). We have already known IL-33/ST2 axis participates in the pathogenesis of various diseases, including liver diseases, renal diseases, and neurological diseases. Recently, emerging studies are indicating that IL-33/ST2 is also involved in a wide range of ocular diseases, such as allergic eye disease, keratitis and corneal regeneration, dry eye disease, uveitis, vitreoretinal diseases, and neuromyelitis optica spectrum disorder. In this review, we will summarize and discuss the current understanding about the functional roles of IL-33/ST2 in eyes, with an attempt to explore the possible study perspectives and therapeutic alternatives in the future.

LncRNA ANRIL knockdown relieves myocardial cell apoptosis in acute myocardial infarction by regulating IL-33/ST2

Objective: To investigate the role of lncRNA ANRIL in the modulation of myocardial cell apoptosis in acute myocardial infarction (AMI).Methods: AMI mice model was established, and lncRNA ANRIL, IL-33 and ST2 expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. The apoptosis of myocardial cells was detected by TUNEL assay. RNA pull-down and RNA immunoprecipitation (RIP) assays were used to confirm the interaction between lncRNA ANRIL and USP17.Results: Compared with sham group, lncRNA ANRIL and ST2 expression levels were up-regulated, and the apoptosis of myocardial cells was increased in heart tissues of AMI group. Compared with normoxia group, the apoptosis of mouse myocardial cell HL-1 and primary murine myocardial cells was increased, and lncRNA ANRIL and ST2 expression levels were up-regulated in hypoxia group. We also found up-regulation of IL-33 in AMI group and hypoxia group. Besides, lncRNA ANRIL affected deubiquitinase USP17-mediated degradation of IL-33. Interfering lncRNA ANRIL reduced the apoptosis of myocardial cells through IL-33/ST2 pathway. In vivo experiments found that interfering lncRNA ANRIL relieved myocardial cell apoptosis and improved heart function in AMI mice.Conclusion: LncRNA ANRIL regulated myocardial cell apoptosis through IL-33/ST2 pathway.

Pleiotropic Effects of IL-33 on CD4+ T Cell Differentiation and Effector Functions

IL-33, a member of the IL-1 family of cytokines, was originally described in 2005 as a promoter of type 2 immune responses. However, recent evidence reveals a more complex picture. This cytokine is released locally as an alarmin upon cellular damage where innate cell types respond to IL-33 by modulating their differentiation and influencing the polarizing signals they provide to T cells at the time of antigen presentation. Moreover, the prominent expression of the IL-33 receptor, ST2, on GATA3+ T helper 2 cells (TH2) demonstrated that IL-33 could have a direct impact on T cells. Recent observations reveal that T-bet+ TH1 cells and Foxp3+ regulatory T (TREG) cells can also express the ST2 receptor, either transiently or permanently. As such, IL-33 can have a direct effect on the dynamics of T cell populations. As IL-33 release was shown to play both an inflammatory and a suppressive role, understanding the complex effect of this cytokine on T cell homeostasis is paramount. In this review, we will focus on the factors that modulate ST2 expression on T cells, the effect of IL-33 on helper T cell responses and the role of IL-33 on TREG cell function.