Molecular evolution of PCSK family: Analysis of natural selection rate and gene loss

Hallmarks of the metabolic secretome

The identification of novel secreted factors is advancing at an unprecedented pace. However, there is a critical need to consolidate and integrate this knowledge to provide a framework of their diverse mechanisms, functional significance, and inter-relationships. Complicating this effort are challenges related to nonstandardized methods, discrepancies in sample handling, and inconsistencies in the annotation of unknown molecules. This Review aims to synthesize the rapidly expanding field of the metabolic secretome, encompassing the five major types of secreted factors: proteins, peptides, metabolites, lipids, and extracellular vesicles. By systematically defining the functions and detection of the components within the metabolic secretome, this Review provides a primer into the advances of the field, and how integration of the techniques discussed can provide a deeper understanding of the mechanisms underlying metabolic homeostasis and its disorders.

[CircPCSK5 is highly expressed in gastric cancer and promotes cancer cell proliferation, invasion and epithelial-mesenchymal transition]

OBJECTIVE

To investigate the expression of circPCSK5 in gastric cancer (GC) and its role in regulation of the proliferation, invasion and epithelial-mesenchymal transition (EMT) of GC cells.

METHODS

High-throughput sequencing was performed in 3 pairs of GC and adjacent gastric mucosa tissues to obtain the differential expression profile of circRNA. The expression of circPCSK5 was detected in 62 patients undergoing radical surgery for GC using RT-qPCR, and the correlation between circPCSK5 expression level and clinicopathological data of the patients was analyzed. The overall survival and disease-free survival of the patients were assessed with Kaplan-Meier survival analysis, and the independent risk factors affecting the patients' prognosis were analyzed using Cox proportional hazards regression model. The stability and subcellular localization of circPCSK5 were assessed using RNase R and actinomycin D assays, fluorescence in situ hybridization and nucleocytoplasmic separation assay. CCK-8 assay, EdU assay and Transwell assay were employed to examine the changes in proliferation, migration and invasion of GC cells with circPCSK5 knockdown or overexpression; Western blotting and RT-qPCR assays were used to detect the expression levels of EMT markers in the transfected cells.

RESULTS

The expression of circPCSK5 was significantly upregulated in GC tissues and cells (P < 0.001, P < 0.01). The expression level of circPCSK5 was positively correlated with tumor size, vascular invasion, lymph node metastasis and AJCC stage of GC (P < 0.05). The overall survival and disease-free survival were significantly lower in GC patients with high circPCSK5 expression than in those with low circPCSK5 expression (P < 0.001). High circPCSK5 expression was an independent risk factor for a poor prognosis of GC patients (P < 0.05). Knockdown of circPCSK5 significantly inhibited the proliferation, migration and invasion of HGC27 cells (P < 0.01), increased the expressions of E-cadherin, and decreased the expression of N-cadherin and vimentin (P < 0.01). CircPCSK5 overexpression promoted the proliferation, migration and invasion of MKN45 cells (P < 0.01), reduced E-cadherin expression and increased N-cadherin and vimentin expressions (P < 0.01).

CONCLUSION

CircPCSK5 is highly expressed in GC and promotes the proliferation, invasion and EMT of GC cells, suggesting its potential as a prognostic biomarker and therapeutic target for GC.

Proprotein convertase subtilisin/kexin type 9 is associated with atherosclerosis in patients with Behcet's disease

OBJECTIVES

The incidence of cardiovascular disease is increased in patients with Behcet's disease (BD). Proprotein convertase subtilisin/kexin type 9 (PCSK9) causes the acceleration of atherosclerosis. We aimed to investigate whether there is a relationship between PCSK9 with carotid artery intima-media thickness (cIMT), a marker of subclinical atherosclerosis, and BD disease activity.

METHODS

Fifty-eight patients with BD and 58 age-, gender-, and body mass index (BMI)-matched healthy control subjects were included in the study. The disease activity of the patients was estimated. Individuals' cIMT values were measured, and PCSK9 levels were studied.

RESULTS

Patients with BD' cIMT (0.51 ± 0.1 vs 0.41 ± 0.1 mm, p < .001) and PCSK9 (623.2 ± 101.7 ± 10.1 vs 528.3 ± 242.7 ng/ml, p = .007), values were significantly higher than the control group. In stepwise regression analysis, there was an independent relationship between cIMT with PCSK9 (β = 0.179, p < .050). There was no independent relationship between disease activities with PCSK9. Based on the ROC curve analysis, the PCSK9 optimal cutoff value for cIMT was 595.1 ng/ml, sensitivity 66.7%, specificity 64.7% (AUC = 0.672; 95% CI: 0.530-0.815, p = .040).

CONCLUSION

There is a strong independent association between subclinical atherosclerosis and PCSK9 in patients with BD. There may be no independent association between PCSK9 and disease activity.