Problem Embryonic loss is a major contributor to infertility. Understanding factors affecting embryonic loss will help increase fertility.
Method of study We investigated if ovine Mx1 (oMx1) mediated secretion by ovine glandular epithelial (oGE) cells using small interfering RNA (siRNA). Effects on secretion were examined through the conventional endoplasmic reticulum-Golgi pathway using β2- microglobulin (β2MG) as a marker, and interferon-stimulated gene 15 (ISG15) as a marker for unconventional secretion.
Results Mx1 siRNA reduced oMx1 mRNA levels at 12 and 24 hr after IFN-τ treatment (P < 0.05), without affecting levels of oMx2, ISG15, 2′,5′-oligoadenylate synthetas or β2MG. Mx1 siRNA reduced Mx1 protein levels at 48 and 120 hr after treatment (P < 0.05) and protein levels remained low at 120 hr. Transient oMx1 knock-down reduced secretion of oMx1 (P < 0.01). ISG15 protein in secretions was reduced without affecting intracellular levels (P < 0.05). Levels of β2MG in secretions were not affected by Mx1 siRNA.
Conclusion We showed that oMx1 protein is secreted by oGE cells and that reduction in oMx1 protein levels by siRNA reduced secretion of ISG15, but not β2MG. Results support the hypothesis that oMx1 is a regulator of secretion through unconventional secretory pathway(s).