CircRNA-3302 promotes endothelial-to-mesenchymal transition via sponging miR-135b-5p to enhance KIT expression in Kawasaki disease

Human cytomegalovirus pUL135 protein affects endothelial cell function via CD2AP in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is a kind of pediatric vasculitis, whose pathogenesis has not been elucidated until now. Many scholars believe that KD is one type of infectious diseases in the susceptible groups. However, no recognized pathogens are confirmed. Human cytomegalovirus (HCMV) is a ubiquitous human herpes virus, which can infect varieties of cells including endothelial cells. Studies reported that the viral protein pUL135 is very important for virus replication, reactivation and immune escape. Therefore, we hypothesize that HCMV pUL135 may have a pathogenic effect on KD.

METHODS

We first determined pUL135 levels in the serum from KD patients. Next, we examined the effects and mechanisms of pUL135 on endothelial cell proliferation and migration. Finally, we assessed the effect of pUL135 on cardiac inflammation in a KD murine model.

RESULTS

Data showed that pUL135 level was significantly increased in the serum from KD patients compared with the healthy and fever controls. And pUL135 expression in endothelial cells remarkably inhibited cell proliferation, migration and tube formation. Moreover, expression of pUL135 obviously affected actin cytoskeleton. Mechanism investigation substantiated that pUL135 mediated endothelial cell dysfunction via regulating CD2AP. Ultimately, we found that HCMV pUL135 aggravated coronary arteritis in the Candida albicans cell wall extracts (CAWS)-induced KD mouse model.

CONCLUSION

Our findings imply that HCMV pUL135-mediated endothelial dysfunction plays an important role in exacerbating coronary artery injury in KD conditions.

circZNF532 promotes endothelial-to-mesenchymal transition in diabetic retinopathy by recruiting TAF15 to stabilize PIK3CD

Endothelial-to-mesenchymal transition (EndMT) is a pivotal event in diabetic retinopathy (DR). This study explored the role of circRNA zinc finger protein 532 (circZNF532) in regulating EndMT in DR progression. Human retinal microvascular endothelial cells (HRMECs) were exposed to high glucose (HG) to induce the DR cell model. Actinomycin D-treated HRMECs were used to confirm the mRNA stability of phosphoinositide-3 kinase catalytic subunit δ (PIK3CD). The interaction between TATA-box-binding protein-associated factor 15 (TAF15) and circZNF532/PIK3CD was subsequently analyzed using RNA immunoprecipitation (RIP), RNA pull-down. It was found that HG treatment accelerated EndMT process, facilitated cell migration and angiogenesis, and enhanced PIK3CD and p-AKT levels in HRMECs, whereas si-circZNF532 transfection neutralized these effects. Further data showed that circZNF532 recruited TAF15 to stabilize PIK3CD, thus elevating PIK3CD expression. Following rescue experiments suggested that PIK3CD overexpression partially negated the inhibitory effect of circZNF532 silencing on EndMT, migration, and angiogenesis of HG-treated HRMECs. In conclusion, our results suggest that circZNF532 recruits TAF15 to stabilize PIK3CD, thereby facilitating EndMT in DR.

Hsa_circ_0081065 exacerbates IH-induced EndMT via regulating miR-665/HIF-1α signal axis and HIF-1α nuclear translocation

CircRNAs play an important role in various physiological and pathological biological processes. Despite their widespread involvement, the function of circRNAs in intermittent hypoxia (IH) remain incompletely understood. This study aims to clarify the molecular mechanism of it in IH. Differentially expressed circRNAs were identified by transcriptome sequencing analysis in intermittent hypoxia (IH) model. GO and KEGG enrichment analys were performed on the identified differentially expressed circRNAs. The circular characteristics of hsa_circ_0081065 in human umbilical vein endothelial cells (HUVECs) were detected by RT-qPCR. The sublocalization of hsa_circ_0081065 was examined by FISH. The effect of hsa_circ_0081065 on endothelial to mesenchymal transition (EndMT) was estimated by detecting the expression of EndMT related markers. Various techniques, including RNA-pull down, RIP, EMSA, dual-luciferase reporter assay and immunofluorescence staining were used to investigate the relationship among hsa_circ_0081065, miR-665 and HIF-1α. A total of 13,304 circRNAs were identified in HUVECs treatment with IH, among which 73 were differentially expressed, including 24 upregulated circRNAs and 49 downregulated circRNAs. Notably, hsa_circ_0081065 demonstrated a significantly upregulation. Hsa_circ_0081065 exhibited the circular characteristics of circRNA and was predominantly localized in the cytoplasm. Knockdown of hsa_circ_0081065 inhibited EndMT. Mechanically, we demonstrated that hsa_circ_0081065 acts as a sponge for miR-665 to up-regulate HIF-1α and exacerbate HIF-1α nuclear translocation in HUVECs. We have demonstrated that hsa_circ_0081065 is significantly upregulated in HUVECs treated with IH. Our findings indicate that hsa_circ_0081065 exacerbates IH-induced EndMT through the regulation of the miR-665/HIF-1α signal axis and facilitating HIF-1α nuclear translocation. These results provide a theoretical basis for considering of EndMT as a potential therapeutic target for OSAHS intervention.

CircRNA7632 down-regulation alleviates endothelial cell dysfunction in Kawasaki disease via regulating IL-33 expression

Kawasaki disease (KD) is a form of idiopathic vasculitis frequently accompanied by coronary artery lesions, which involves endothelial dysfunction. Recent studies have demonstrated that circular RNAs (circRNAs) are implicated in many cardiovascular diseases. However, few studies have examined the role of circRNAs on endothelial dysfunction in KD. In this study, we investigated the role of circ7632 on endothelial-mesenchymal transition (EndoMT) in KD and then explored the underlying mechanism. Children diagnosed with KD and age-matched healthy controls (HC) were included. Sera samples were collected. Primary human umbilical vein endothelial cells (HUVECs) were obtained and incubated with 15% HC and KD serum for 48 h. The mRNA and protein expression of mesenchymal markers vimentin and α-smooth muscle actin (α-SMA) and endothelial marker zonula occludens-1 (ZO-1) in HUVECs transfected with plasmid-circ7632 and si-circ7632 were detected by RT-qPCR and Western blot analysis. CCK8, scratch test, and migration test were performed to examine the effect of circ7632 on the cell proliferation and migration. The circ7632 level was higher in HUVECs treated by KD serum than in HUVECs treated with HC serum. Overexpression of circ7632 significantly increased vimentin and α-SMA expression, decreased ZO-1 expression, and also decreased cell proliferation. Down-regulation of circ7632 expression got the opposite results. RNA-seq analysis, and confirmatory experiment displayed that down-regulation of circ7632 decreased IL-33 expression, and IL-33 silencing mitigated KD serum-mediated EndoMT. Our study revealed that circ7632 level was elevated in KD serum-treated HUVECs. Circ7632 down-regulation could alleviate EndoMT likely through decreasing IL-33 expression. The circ7632 may become a potential therapeutic target for KD.