Comparison of Siglec-1 protein networks and expression patterns in sperm and male reproductive tracts of mice, rats, and humans.

Background: Sialic acid-binding immunoglobulin-like lectin 1 (Siglec-1) is a transmembrane glycoprotein involved in the sialic acid (Sia)-dependent regulation of the immune system. Siglec-1 expression has recently been identified in the male reproductive tract (MRT) of several species, including humans, cattle, horses, and sheep, and may play a role in modulating fertility in a Sia-dependent manner. Materials and Methods: In this study, protein-protein interaction (PPI) analysis of Siglec-1 was conducted to identify associated network protein conservation, and the expression of Siglec-1 in the MRT of mice and rats, including their accessory sex glands and spermatozoa was determined by immunostaining. Results: Network analysis of proteins with Siglec-1 in mice and rats demonstrated significant similarity to human Siglec-1 networks, suggesting a similar conservation of network proteins between these species and, hence, a potential conservation role in immune modulation and function. Specific immunostaining patterns of mouse and rat testes, epididymis, ductus deferens, accessory sex gland tissues, and sperm were detected using human Siglec-1. These results confirmed that the human Siglec-1 antibody could cross-react with mouse and rat Siglec-1, suggesting that the specific expression patterns of Siglec-1 in the MRT and sperm of both mice and rats are similar to those observed in other species. Conclusions: The conservation of Siglec-1 expression patterns in sperm and within the MRT and the similarity of protein networks for Siglec-1 across species suggest that Siglec-1 may function in a similar manner across species. These results also suggest that rodents may serve as a valuable model system for exploring the function of Siglecs in the reproductive system across species and their potential role in modulating fertility in a Sia-dependent manner.

Synthetic chemically modified mrna-based delivery of cytoprotective factor promotes early cardiomyocyte survival post-acute myocardial infarction.

To extend the temporal window for cytoprotection in cardiomyocytes undergoing apoptosis after hypoxia and myocardial infarction (MI), a synthetic chemically modified mRNA (modRNA) was used to drive delivery of insulin-like growth factor-1 (IGF1) within the area at risk in an in vivo murine model of MI. Delivery of IGF1 modRNA, with a polyethylenimine-based nanoparticle, augmented secreted and cell-associated IGF1, promoting cardiomyocyte survival and abrogating cell apoptosis under hypoxia-induced apoptosis conditions. Translation of modRNA-IGF1 was sufficient to induce downstream increases in the levels of Akt and Erk phosphorylation. Downregulation of IGF1 specific miRNA-1 and -133 but not miR-145 expression was also confirmed. As a proof of concept, intramyocardial delivery of modRNA-IGF1 but not control modRNA-GFP significantly decreased the level of TUNEL positive cells, augmented Akt phosphorylation, and decreased caspase-9 activity within the infarct border zone 24 h post-MI. These findings demonstrate the potential for an extended cytoprotective effect of transient IGF1 driven by synthetic modRNA delivery.

Effect of apocynin on NADPH oxidase-mediated oxidative stress-LOX-1-eNOS pathway in human endothelial cells exposed to high glucose.

Hyperglycemia-induced generation of reactive oxygen species contributes to the development of proatherogenic changes and vasculopathy in diabetes. NADPH oxidase has been recognized as a major source of reactive oxygen species in the vasculature and the lectin-like oxLDL receptor-1 (LOX-1) appears to play a crucial role in the pathogenesis of diabetic endothelial dysfunction. The present study aimed to examine the relationships between the hyperglycemia-mediated NADPH oxidase-LOX-1 pathway activation and nitric oxide-mediated endothelial function. In addition, we investigated effect of the NADPH oxidase inhibitor, apocynin on these consequences. In human umbilical artery endothelial cells (HUAECs), the effect of high glucose on expressional regulations and functional consequences of NADPH oxidase subunits, LOX-1 and endothelial nitric oxide synthase (eNOS), in the absence and presence of apocynin (10 micromol/l) were evaluated. HUAECs were cultured under normal (5.5 mmol/l) or high glucose (30mmol/l) concentrations for 48 h in the absence and presence of apocynin. Our results showed that high glucose significantly enhanced the activity and the protein expression of NADPH oxidase subunits, Nox2 and p47(phox). High glucose markedly increased LOX-1 mRNA level and this was functionally reflected on the augmented uptake of Dil-labelled LDL (5 micromol/l, 3h) by HUAECs. Furthermore, high glucose attenuated eNOS protein and total nitrite levels. However, apocynin inhibited all these changes. Collectively, our study demonstrates that high glucose-induced oxidative stress via NADPH oxidase activation and this contributed to LOX-1 upregulation and eNOS downregulation in human endothelial cells. Apocynin efficiently reversed these consequences, suggesting its potential role as a vasculoprotective agent.