LDL oxidation by THP-1 monocytes: Implication of HNP-1, SgIII and DMT-1

SCG3 Protein Expression in Glioma Associates With less Malignancy and Favorable Clinical Outcomes

Introduction: Secretogranin III (SCG3) physiologically participates in neurotransmitter storage/transport and is widely expressed in neuroendocrine tumors. However, there is no report on SCG3 protein expression in gliomas. Methods: The method of immunohistochemical staining on a glioma tissue microarray was utilized to detect SCG3 protein expression and investigate the correlations of its expression with clinicopathological and genetic features in gliomas. The RNA-seq data of SCG3 in The Cancer Genome Atlas database was exploited to explore these correlations at the transcriptional level. Results: There were 57.5% (130/226) glioma cases having SCG3 cytoplasmic staining in the tissue microarray. SCG3 expression inversely correlated with malignancy grade at both transcriptional and protein levels. The highest level was observed in oligodendroglial tumors, especially in oligodendrogliomas (ODs) with IDH-mutation/1p19q-codeletion. The lowest SCG3 expression was observed in glioblastomas (GBMs), especially in the mesenchymal subtype. Nearly a half of GBM cases (44.4%, 64/144) had any discernible SCG3 staining, and were defined as SCG3-positive by the microarray study. SCG3-positive GBM cases exhibited improved overall survival as compared with the SCG3-negative cases (29.3 vs. 14.5 months; Hazard ratio, 0.364; 95% CI, 0.216-0.612; p < 0.001). A multivariate Cox regression analysis also revealed SCG3 positivity as an independent favorable prognosticator in GBM patients. Conclusion: SCG3 protein expression inversely correlates with glioma malignancy and predicts favorable outcomes in GBM patients.

The oncoprotein HBXIP up-regulates SCG3 through modulating E2F1 and miR-509-3p in hepatoma cells

Hepatitis B X-interacting protein (HBXIP) is an important oncoprotein in hepatocarcinogenesis. Here, we found that the expression levels of HBXIP were positively associated with those of Secretogranin III (SCG3) in clinical hepatocellular carcinoma tissues. We identified that HBXIP up-regulated the expression of SCG3 through modulating both E2F transcription factor 1 (E2F1) and miR-509-3p. HBXIP suppressed miR-509-3p through activating NF-κB. In function, we showed that SCG3 increased the proliferation of hepatoma cells and HBXIP enhanced the proliferation of the cells via SCG3 in vitro and in vivo. Thus, we conclude that HBXIP facilitates the proliferation of hepatoma cells through up-regulating SCG3.

Leukocyte and leukocyte subset counts reveal compensatory mechanisms in coronary heart disease

BACKGROUND

Leukocyte number in the circulation plays a central role in inflammatory diseases, such as coronary heart disease (CHD). Increased counts are correlated with the intensity of the peri-infarction inflammatory response and adverse outcomes. We investigated leukocyte and leukocyte subset counts in dyslipidaemia patients and their relationship with LDL oxidation.

METHODS

Dyslipidaemia patients (207) were selected for blood counts and LDL-C testing. The level of HNP-1and myeloperoxidase in subsets of leukocytes and their relationship with LDL oxidation were compared between 24 CHD patients and 24 normal controls.

RESULTS

In dyslipidaemia patients, total leukocyte and neutrophil counts increased with LDL-C (p=0.001). Monocyte counts showed the opposite trend (p=0.001). Although serum HNP-1 levels were not different between CHD patients and normal controls (p=0.558), neutrophil HNP-1 mRNA levels were 2.13-fold greater than those of normal controls. However, monocyte HNP-1 mRNA levels were lower (p=0.005). The distribution of myeloperoxidase in monocytes and neutrophils is different, myeloperoxidase locates mainly in the cytoplasm of monocytes, on the cell membrane of neutrophils.

CONCLUSIONS

Leukocyte and leukocyte subset counts may correlate with LDL-C levels and LDL oxidation. The monocyte-neutrophil interaction reveals a potential compensatory mechanism associated with LDL oxidation in CHD that may be a prognostic factor of CHD.

Dysregulated expression of secretogranin III is involved in neurotoxin-induced dopaminergic neuron apoptosis

The neurotoxins paraquat (PQ) and dopamine (DA or 6-OHDA) cause apoptosis of dopaminergic neurons in the substantia nigra pars compacta (SNpc), reproducing an important pathological feature of Parkinson's disease (PD). Secretogranin III (SCG3), a member of the multifunctional granin family, plays a key role in neurotransmitter storage and transport and in secretory granule biogenesis, which involves the uptake of exogenous toxins and endogenous "toxins" in neuroendocrine cells. However, the molecular mechanisms of neurotoxin-induced apoptosis in dopaminergic neurons and the role of SCG3-associated signaling pathways in neuroendocrine regulation are unclear. To address this, we used PQ- and DA-induced apoptosis in SH-SY5Y human dopaminergic cells as an in vitro model to investigate the association between SCG3 expression level and apoptosis. SCG3 was highly expressed in SH-SY5Y cells, and SCG3 mRNA and protein levels were dramatically decreased after PQ treatment. Apoptosis induced by PQ is associated with caspase activation and decreased SCG3 expression, and restoration of SCG3 expression is observed after treatment with caspase inhibitors. Overexpressed SCG3 in nonneuronal cells and endogenous SCG3 in SH-SY5Y cells are cleaved into specific fragments by recombinant caspase-3 and -7, but the fragments were not detected in PQ-treated SH-SY5Y cells. Therefore, SCG3 may be involved in apoptosis signal transduction as a caspase substrate, leading to loss of its original biological functions. In addition, SCG3 may be a pivotal component of the neuroendocrine pathway and play an important role in neuronal communication and neurotransmitter release, possibly representing a new potential target in the course of PD pathogenesis.

Acute ST-segment elevation myocardial infarction is associated with decreased human antimicrobial peptide LL-37 and increased human neutrophil peptide-1 to 3 in plasma

AIM

Increasing evidence indicates that antimicrobial peptides, human neutrophil peptide-1, -2, and -3 (HNP1-3) and human antimicrobial peptide LL-37 are involved in the pathophysiology of atherosclerosis; however, little is known about their circulating protein levels in acute myocardial infarction (AMI). We therefore investigated whether their plasma levels are associated with stable coronary artery disease (CAD) and acute ST-segment elevation myocardial infarction (STEMI).

METHODS

Systemic or local (culprit artery) blood samples were obtained from 112 consecutive male subjects including no CAD (n = 31) controls, stable CAD (n = 44) and STEMI (n = 47). Plasma HNP1-3 and LL-37 levels were measured by the ready-to-use solid-phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle.

RESULTS

Systemic HNP1-3 in STEMI was increased compared with no CAD (p = 0.000) and stable CAD (p = 0.008), and systemic HNP1-3 in stable CAD was higher than in no CAD (p = 0.004). Systemic LL-37 in STEMI was decreased compared with no CAD (p = 0.009) and stable CAD (p =0.001) and restored within 1 day following STEMI (p = 0.000). Local LL-37 levels in STEMI were higher than systemic levels (p = 0.013). The areas under the ROC curve of systemic HNP1-3 and LL-37 for STEMI were 0.717 (95% CI: 0.624, 0.811; p = 0.000) and 0.702 (95% CI: 0.609, 0.795; p = 0.000), respectively. In addition, ischemia time in the STEMI group correlated with systemic and local levels of HNP1-3 (rs = -0.360, p = 0.013; rs = 0.608, p = 0.000, respectively), and was also associated with systemic and local levels of hs-CRP (rs = 0.408, p = 0.004; rs = 0.425, p = 0.003, respectively), but not with those of LL-37 (all p > 0.05).

CONCLUSION

STEMI was associated with transiently decreased LL-37, but persistently increased HNP1-3 in the systemic circulation and the diagnostic accuracy for STEMI were moderate. Future studies should pay more attention to their prognostic values for myocardial infarction.