THBS1: a potential biomarker for atrial fibrillation

Circ_0079480 facilitates proliferation, migration and fibrosis of atrial fibroblasts in atrial fibrillation by sponing miR-338-3p to activate the THBS1/TGF-β1/Smad3 signaling

BACKGROUND

Atrial fibrosis is associated with the pathogenesis of atrial fibrillation (AF). This study aims to discuss the function of circ_0079480 in atrial fibrosis and its underlying mechanism.

METHODS

In vitro and in vivo models of atrial fibrosis were established by using angiotensin II (Ang II) to treat human atrial fibroblasts (HAFs) and C57/B6J mice. qRT-PCR and western blot were used to examine the mRNA and protein expression levels. CCK-8, EdU, cell strach, and transwell assays were performed to determine the proliferation and migration of HAFs. Dual-luciferase reporter and RIP/RNA pull-down assays were explored to identify the interaction of miR-338-3p and circ_0079480/THBS1. HE and Masson's trichrome staining experiments were performed to analyze the histopathological change in mice atrial tissues.

RESULTS

Circ_0079480 expression was increased in AF patients' atrial tissues and Ang II-treated HAFs. Silencing circ_0079480 inhibited cell proliferation and migration and reduced fibrosis-associated gene expression in Ang II-treated HAFs. Circ_0079480 could target miR-338-3p to repress its expression. MiR-338-3p inhibitor blocked the inhibitory effects of circ_0079480 knockdown on HAFs proliferation, migration, and fibrosis. Thrombospondin-1 (THBS1) was confirmed as a downstream target of miR-338-3p, and circ_0079480 could sponge miR-338-3p to upregulate THBS1 expression. Moreover, silencing THBS1 suppressed Ang II-induced proliferation, migration, and fibrosis in HAFs. More importantly, depletion of circ_0079480 inactivated the THBS1/TGF-β1/Smad3 signaling by upregulating miR-338-3p. Mice experiments also confirmed the suppression of circ_0079480 knockdown on atrial fibrosis.

CONCLUSION

Circ_0079480 acts as a sponge of miR-338-3p to upregulate THBS1 expression and activate the TGF-β1/Smad3 signaling, finally promoting Ang II-induced atrial fibrosis.

Association of THBS1 genetic variants and mRNA expression with the risks of ischemic stroke and long-term death after stroke

Background

Thrombospondin-1 (THBS1) derived from platelets and acted as a critical mediator of hemostasis promoting platelet activation in thrombus formation. The biological connection of genetic variants and mRNA expression of THBS1 with ischemic stroke (IS) warrants further validation with population-based evidence.

Objective

To evaluate the association of single nucleotide polymorphisms (SNPs) and mRNA expression of THBS1 with the risks of IS and long-term death after stroke.

Methods

A case-control study consisted of 4,584 IS patients recruited from five hospitals in Jiangsu, China, and 4,663 age-gender-matched controls free of IS. A cohort study enrolled 4,098 participants free of stroke and lasted from 2009 to 2022. Early collected 3158 IS patients aged between 35 and 80 years were followed up an average of 5.86-year to follow up their long-term death outcomes. Two tagSNPs of the THBS1 gene, rs2236471 and rs3743125, were genotyped in all subjects and THBS1 mRNA expression of peripheral leukocyte was measured using RT-qPCR in 314 IS cases and 314 controls.

Results

There is no significant difference in genotype and haplotype frequencies of rs2236741 and rs3743125 between IS cases and controls (all P > 0.05). Furthermore, the cohort studies did not observe significant associations between THBS1 variants and the risk of IS incidence or long-term death after IS (all P > 0.05). The THBS1 mRNA expression level (2^–ΔΔCT) in IS cases was approximately equal to that in controls (1.01 vs. 0.99, P = 0.833). In addition, THBS1 mRNA expression had no significant association with all-cause death, stroke death, and IS death of IS patients (all P > 0.05).

Conclusion

Therefore, our study suggested that there is no significant association of THBS1 polymorphisms and mRNA expression level with the risk of IS and long-term death after IS.

Identification of immune-related hub genes and miRNA-mRNA pairs involved in immune infiltration in human septic cardiomyopathy by bioinformatics analysis

Abstract

Septic cardiomyopathy (SCM) is a serious complication caused by sepsis that will further exacerbate the patient's prognosis. However, immune-related genes (IRGs) and their molecular mechanism during septic cardiomyopathy are largely unknown. Therefore, our study aims to explore the immune-related hub genes (IRHGs) and immune-related miRNA-mRNA pairs with potential biological regulation in SCM by means of bioinformatics analysis and experimental validation.

Method

Firstly, screen differentially expressed mRNAs (DE-mRNAs) from the dataset GSE79962, and construct a PPI network of DE-mRNAs. Secondly, the hub genes of SCM were identified from the PPI network and the hub genes were overlapped with immune cell marker genes (ICMGs) to further obtain IRHGs in SCM. In addition, receiver operating characteristic (ROC) curve analysis was also performed in this process to determine the disease diagnostic capability of IRHGs. Finally, the crucial miRNA-IRHG regulatory network of IRHGs was predicted and constructed by bioinformatic methods. Real-time quantitative reverse transcription-PCR (qRT-PCR) and dataset GSE72380 were used to validate the expression of the key miRNA-IRHG axis.

Result

The results of immune infiltration showed that neutrophils, Th17 cells, Tfh cells, and central memory cells in SCM had more infiltration than the control group; A total of 2 IRHGs were obtained by crossing the hub gene with the ICMGs, and the IRHGs were validated by dataset and qRT-PCR. Ultimately, we obtained the IRHG in SCM: THBS1. The ROC curve results of THBS1 showed that the area under the curve (AUC) was 0.909. Finally, the miR-222-3p/THBS1 axis regulatory network was constructed.

Conclusion

In summary, we propose that THBS1 may be a key IRHG, and can serve as a biomarker for the diagnosis of SCM; in addition, the immune-related regulatory network miR-222-3p/THBS1 may be involved in the regulation of the pathogenesis of SCM and may serve as a promising candidate for SCM therapy.