Serum exosomal microRNA let-7i-3p as candidate diagnostic biomarker for Kawasaki disease patients with coronary artery aneurysm.

Kawasaki disease (KD) is a systemic vasculitis syndrome that leads to coronary artery aneurysm (CAA). While echocardiography is the most important imaging modality for coronary artery assessment, a specific diagnostic biomarker complementary for CAA has not been reported. We aimed to analyze the profiles of exosomal miRNAs extracted from the serum of KD patients and controls to identify candidate biomarkers for CAA. Serum samples from 39 healthy children, 42 CAA patients, 38 coronary artery dilatation (CAD) patients and 45 virus-infected patients including 24 EBV patients and 21 ADV patients were randomly selected. Next generation sequencing was used to analyze serum exosomal miRNA to detect differentially expressed miRNAs. Biomarker candidates were validated by qRT-PCR. One hundred (and) ninety-six differentially expressed miRNAs (DEMs) were detected in CAA patients and healthy children. There were 70 DEMs and 140 DEMs in CAA patients versus CAD patients, and in CAA patients versus virus-infected patients, respectively. We selected the three most upregulated (let-7i-3p, miR-17-3p, and miR-210-5p) and the three most downregulated miRNAs (miR-6743-5p, miR-1246, and miR-6834-5p) in the DEMs, which were expressed differentially in CAA patients versus healthy children, and in CAA patients versus virus-infected patients, not in virus-infected patients versus healthy children, as biomarker candidates. Excluded DEMs of CAD and virus-infected patients, let-7i-3p was detected by sequence data analysis as a biomarker candidate for CAA patients, and then validated by qRT-PCR in a larger set of clinical samples. As a biomarker candidate, let-7i-3p provides an additional means of diagnosing CAA patients. Additionally, miRNA biomarkers complement ultrasonic imaging, allowing for greater diagnostic precision. © 2019 IUBMB Life, 2019.

Differential protein analysis of serum exosomes post-intravenous immunoglobulin therapy in patients with Kawasaki disease.

BACKGROUND: Kawasaki disease, which is characterised by systemic vasculitides accompanied by acute fever, is regularly treated by intravenous immunoglobulin to avoid lesion formation in the coronary artery; however, the mechanism of intravenous immunoglobulin therapy is unclear. Hence, we aimed to analyse the global expression profile of serum exosomal proteins before and after administering intravenous immunoglobulin. METHODS: Two-dimensional electrophoresis coupled with mass spectrometry analysis was used to identify the differentially expressed proteome of serum exosomes in patients with Kawasaki disease before and after intravenous immunoglobulin therapy. RESULTS: Our analysis revealed 69 differential protein spots in the Kawasaki disease group with changes larger than 1.5-fold and 59 differential ones in patients after intravenous immunoglobulin therapy compared with the control group. Gene ontology analysis revealed that the acute-phase response disappeared, the functions of the complement system and innate immune response were enhanced, and the antibacterial humoral response pathway of corticosteroids and cardioprotection emerged after administration of intravenous immunoglobulin. Further, we showed that complement C3 and apolipoprotein A-IV levels increased before and decreased after intravenous immunoglobulin therapy and that the insulin-like growth factor-binding protein complex acid labile subunit displayed reverse alteration before and after intravenous immunoglobulin therapy. These observations might be potential indicators of intravenous immunoglobulin function. CONCLUSIONS: Our results show the differential proteomic profile of serum exosomes of patients with Kawasaki disease before and after intravenous immunoglobulin therapy, such as complement C3, apolipoprotein A-IV, and insulin-like growth factor-binding protein complex acid labile subunit. These results may be useful in the identification of markers for monitoring intravenous immunoglobulin therapy in patients with Kawasaki disease.

Plasminogen kringle 5 induces endothelial cell apoptosis by triggering a voltage-dependent anion channel 1 (VDAC1) positive feedback loop.

Human plasminogen kringle 5 (K5) is known to display its potent anti-angiogenesis effect through inducing endothelial cell (EC) apoptosis, and the voltage-dependent anion channel 1 (VDAC1) has been identified as a receptor of K5. However, the exact role and underlying mechanisms of VDAC1 in K5-induced EC apoptosis remain elusive. In the current study, we showed that K5 increased the protein level of VDAC1, which initiated the mitochondrial apoptosis pathway of ECs. Our findings also showed that K5 inhibited the ubiquitin-dependent degradation of VDAC1 by promoting the phosphorylation of VDAC1, possibly at Ser-12 and Thr-107. The phosphorylated VDAC1 was attenuated by the AKT agonist, glycogen synthase kinase (GSK) 3ß inhibitor, and siRNA, suggesting that K5 increased VDAC1 phosphorylation via the AKT-GSK3ß pathway. Furthermore, K5 promoted cell surface translocation of VDAC1, and binding between K5 and VDAC1 was observed on the plasma membrane. HKI protein blocked the impact of K5 on the AKT-GSK3ß pathway by competitively inhibiting the interaction of K5 and cell surface VDAC1. Moreover, K5-induced EC apoptosis was suppressed by VDAC1 antibody. These data show for the first time that K5-induced EC apoptosis is mediated by the positive feedback loop of "VDAC1-AKT-GSK3ß-VDAC1," which may provide new perspectives on the mechanisms of K5-induced apoptosis.

[Effect of small interfering RNA on matrix metalloproteinase-9 expression in vascular endothelial cells stimulated by serum from children with Kawasaki disease].

OBJECTIVE: To investigate the matrix metalloproteinase-9 (MMP-9) expression in vascular endothelial cells stimulated by the serum obtained from children with Kawasaki disease (KD) during the acute phase in the absence and presence of MMP-9 small interfering RNA (siRNA). METHODS: MMP-9 siRNA plasmids were constructed and transduced into vascular endothelial cells (ECV-304) by liposomal transfection. ECV-304 were cultured in 6 different conditional media: KD serum + siRNA negative control, normal serum, KD serum + MMP-9 siRNA1 (pSilencer3.1-MMP1), KD serum + MMP-9 siRNA2 (pSilencer3.1-MMP2), KD serum + gamma-globulin, and KD serum. RT-PCR and Western blot were used to detect MMP-9 expression at mRNA and protein levels in ECV-304. RESULTS: The mRNA and protein expression of MMP-9 in ECV-304 cultured with 10% serum from KD patients (2.49 +/- 0.03, 1.20 +/- 0.04) and KD serum + siRNA negative control plasmid (2.45 +/- 0.03, 1.15 +/- 0.03) were significantly higher than those cultured with 10% serum from normal control children (1.21 +/- 0.03, 0.52 +/- 0.03, respectively; all P < 0.01) and the increased MMP-9 expression could be significantly inhibited by MMP-9 siRNA1, MMP-9 siRNA2 and gamma-globulin (100 mg/ml, all P < 0.01). CONCLUSIONS: The increase of MMP-9 expression in vascular endothelial cells induced by the serum from KD patients might take part in the formation of coronary artery lesions. Two customized MMP-9 siRNA plasmids (pSilencer3.1-MMP1 and pSilencer3.1-MMP2) can significantly inhibit both MMP-9 mRNA and protein expression.

[Detection and analysis of SARS coronavirus-specific antibodies in sera from non-SARS children].

OBJECTIVE: To examine the presence of severe acute respiratory syndrome (SARS) coronavirus-specific antibodies in the sera from non-SARS children. METHODS: Indirect immunofluorescent assay and double-antigen sandwich enzyme-linked immunosorbent assay (ELISA) were used to detect the virus-specific antibodies in sera of 1,060 non-SARS children in Guangzhou. RESULTS: All the serum samples from the 1,060 non-SARS children were negative for both IgG and IgM antibodies against SARS coronavirus as determined by indirect immunofluorescent assay, with only two serum samples showing weak positivity for SARS coronavirus-specific antibodies identified by double-antigen sandwich ELISA. CONCLUSION: No SARS coronavirus-specific antibody are present in the sera of non-SARS children.