LAMP-2 gene expression in peripheral leukocytes is increased in patients with coronary artery disease

Autophagy-mediated expression clusters are involved in immunity regulation of coronary artery disease

BACKGROUND

The association between autophagy and immunity, including infiltrating immunocytes, immune reaction gene-sets, and HLAs (human leukocyte antigen) gene, remains unclear. The present study aimed to provide a valid diagnostic tool for coronary artery disease (CAD), and explore the pathological mechanisms of CAD based on the association between autophagy and immunity.

METHODS

First, the overlap between differentially expressed genes (DEGs) and autophagy-related genes (ARGs) was identified. Subsequently, machine learning was conducted to screen risk genes closely related to CAD. Diverse autophagy phenotype-related clusters were identified using unsupervised clustering. The connections between different clusters and immune characteristics were evaluated as well.

RESULTS

The present study identified 27 differentially expressed autophagy-related genes (DEAGRs) in CAD samples compared with healthy conrtrols. A classifier constructing by 9 DEARGs was regarded as an effective diagnostic tool for CAD. Furthermore, three distinct autophagy phenotype - related clusters were identified, each cluster exhibited different immune characteristics. Finally, the gene ontology (GO) analysis of 901 autophagy phenotype-related genes showed that immune response, protein phosphorylation, and innate immune response were remarkable enrichment components.

CONCLUSIONS

This study identified an effective classifier constituted by 9-DEARGs that has good diagnostic performance for CAD, and revealed that autophagy and the immunity may be common critical factors in the occurrence and development of CAD.

Altered expression of lysosomal hydrolase, acid α-glucosidase, gene in coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a common complex disease caused by atherosclerosis. Autophagy is a cellular degradation process that delivers long-lived macromolecules and dysfunctional organelles into lysosomes for digestion. Autophagy regulates lipid and cholesterol metabolism. We have previously shown that expression of autophagic and lysosomal genes is altered in CAD patients. In this study, we investigated gene expression of a lysosomal hydrolase, acid α-glucosidase (GAA), in CAD patients and controls.

METHODS

GAA gene expression was examined in large cohorts of CAD patients (n=248) and ethnically matched controls (n=208). GAA enzymatic activity, protein levels, and transcript levels were determined and compared between CAD patients and controls.

RESULTS

GAA activities in CAD patients were significantly elevated (P<0.05) compared with controls. Consistently, GAA transcription levels were also significantly increased in CAD patients (P<0.01). Multivariate logistic regression analyses (GAA transcript level, hypertension, diabetes, and smoking) revealed that GAA transcript levels were strongly associated with CAD (odds ratio 5.93, 95% confidence interval 2.98-11.78, P=3.89×10(-7)). GAA protein levels were insignificantly increased in CAD patients (P>0.05), likely due to assay insensitivity.

CONCLUSION

Compared with controls, GAA gene expression levels in CAD patients were significantly increased, suggesting that GAA may be involved in the CAD development.

Lysosome-associated protein 1 (LAMP-1) and lysosome-associated protein 2 (LAMP-2) in a larger family carrier of Fabry disease

This study investigated the potential relationship between the expression levels of lysosome-associated membrane proteins (LAMP) 1 and 2 and responses to enzyme replacement therapy (ERT) in the members of a single family with Fabry disease (FD). LAMP levels were assessed by flow cytometry in leukocytes from 17 FD patients who received an eight-month course of ERT course and 101 healthy individuals. We found that phagocytic cells from the FD patients had higher expression levels of both LAMP-1 and LAMP-2, relative to the levels in phagocytes from the healthy controls (p=0.001). Furthermore, the LAMP-1 and LAMP-2 levels in phagocytes from the FD carriers continuously decreased with ERT administration to reach levels similar to those in healthy controls. We suggest that LAMP-1 and LAMP-2 could be used as additional markers with which to assess ERT effectiveness in FD.

Age-related decrease of the LAMP-2 gene expression in human leukocytes

OBJECTIVE

Autophagy is a highly conserved degradation pathway in cells, which has been involved in many physiological processes and implicated in human age-related diseases. However, autophagy activities have not been systemically investigated with human tissues and cells.

METHODS

Lysosomal associated membrane protein-2 (LAMP-2) protein is critical for autophagy and chaperone-mediated autophagy. We examined LAMP-2 gene expression and protein levels in the peripheral leukocytes from healthy subjects over 40 years old.

RESULTS

Compared to those in group of 40-44 years, the LAMP-2 transcript and protein levels in groups of 65-69 (P<0.01) and over 70 years (P<0.001) were significantly decreased. No significant difference in LAMP-2 transcript and protein levels were observed between male and female groups.

CONCLUSIONS

Our data revealed that there was a progressive and age-related decrease of the LAMP-2 gene expression in the peripheral leukocytes of healthy subjects, indicating a trend of decreasing autophagy activities with aging.

Alterations of autophagic-lysosomal system in the peripheral leukocytes of patients with myocardial infarction

BACKGROUND

Myocardial infarction (MI) is a common and multifactorial disease. To date, causal genes and underlying mechanisms remain largely unknown. Autophagic-lysosomal system, a highly conserved degradative process in cells, has been implicated in lipid metabolism. In this study, we explored the alterations of the autophagic-lysosomal system in patients with acute MI.

METHODS

Gene expression of lysosomal associated membrane protein 2 (LAMP-2), a lysosomal marker gene, and microtubule-associated protein 1 light chain 3 (LC3), an autophagy marker gene, in the peripheral leukocytes of MI patients were examined at transcription and protein levels by RT-PCR assay and western blot analysis, respectively.

RESULTS

Compared to age- and sex-matched healthy controls (n=146), levels of LC3 gene expression and LC3-II protein, a cleaved form of LC3 protein, were significantly decreased in MI patients (n=81). LAMP-2 gene expression and protein levels were significantly increased. Decreased LC3 gene expression (OR, 2.150, 95%CI, 1.050-4.405, P=0.036) or increased LAMP-2 gene expression (OR, 3.317, 95%CI, 1.588-6.931, P<0.001) levels were associated with MI.

CONCLUSIONS

Our findings indicated that in the peripheral leukocytes of MI patients, autophagy activity is reduced and lysosomal accumulation is increased, which may contribute to the MI pathogenesis. Further genetic analyses of autophagic-lysosomal genes are warranted.