Effect Of STMN2 On Ras-MAPK Signaling In Granulosa Cells Of Hks

STMN2, a microtubule-destabilizing protein expressed in the nucleus, affects mitotic spindle formation by promoting depolymerization or preventing polymerization of microtubules. Studies have revealed that STMN2 expression in pituitary gland of laying hens is significantly higher than that in hens not laying eggs. The Ras-MAPK signaling pathway is one of the most important signaling pathways within cells, involved in regulation of multiple physiological processes and playing an important role in animal breeding. Through literature review, it was found that STNM2 expression is significantly elevated in poultry granulosa cells, and it’s suspected that STNM2 may regulate mitosis of these cells via the Ras-MAPK signaling pathway. So we investigated the effect of different levels of STMN2 expression on m RNA and protein levels of components of the Ras-MAPK signaling pathway, including erk1, erk2, ras, elk-1; and we also tested the effect of Ras-MAPK activation or inhibition on STMN2 m RNA and protein expression. By revealing the interaction between STMN2 and the Ras-MAPK signaling pathway, we seek to provide theoretical basis to improve yield of the HKs.8-month-old healthy laying HKs were selected for this study, and primary granulosa cells were cultured.STMN2 in these cells were overexpressed or suppressed by infection with STMN2-overexpressing or STMN2-suppressing adenoviruses, with corresponding empty vector and uninfected cells as control. Then m RNA and protein levels of key components of the Ras-MAPK signaling pathway were assessed by fluorescence quantitative PCR and Western blot. Then the primary granulosa cells were also treated with activator or inhibitor of the Ras-MAPK signaling pathway to see their effect on STMN2 m RNA and protein expression.Results:1. The effect of STMN2 overexpression on key components of the Ras-MAPK signaling pathway Compared to the empty vector group and control group, the STMN2 overexpressing group showed significantly higher m RNA expression of erk1, erk2, ras(p<0.01) and elk-1(p<0.05); and significantly higher protein expression of erk1, erk2, p-erk1, p-erk2 and ras(p<0.01) but elk-1.2. The effect of STMN2 suppression on key components of the Ras-MAPK signaling pathway Compared to the empty vector group and control group, the STMN2 suppression showed significantly lower m RNA expression of erk1, elk-1(p<0.01), ras, and erk2(p<0.01); and significantly lower expression of all tested proteins.3. The effect of Ras-MAPK signaling pathway on STMN2 expression Compared to the activator and control group, the inhibitor group showed significantly lower expression of STMN2 m RNA and protein(p<0.05); while the activator group showed significantly higher STMN2 m RNA and protein expression compared to the inhibitor and control group(p<0.05).These results indicated that STMN2 and Ras-MAPK signaling pathway regulate each other, and STMN2 may promote growth, development, and proliferation of granulosa cells, by regulating the Ras-MAPK signaling pathway.