Dynamic changes in sumoylation related proteins SUMO1, SENP1, and UBC9 during the peri implantation period in mice

Abstract

The healthy progression and termination of pregnancy depend critically upon embryo development, acquisition of uterine receptivity, implantation, and decidualization during the peri-implantation period. Sumoylation is a post-translational modification that affects the stability, transcriptional activity, and cellular localization of proteins. In our study, we investigated the localization and expression of SUMO1 (small ubiquitin-like modifier), SENP1 (sentrin-specific protease 1), and UBC9 (SUMO-conjugated enzyme UBC9), members of the sumoylation mechanism, in the mouse uterus and implantation sites during the peri-implantation period. Localization and expressions of SUMO1, SENP1, and UBC9 were determined by immunohistochemistry and Western blot, respectively. Estrogen (E₂) and progesterone (P₄) levels were measured by ELISA. SUMO1 was at the highest level in the luminal and gland epithelium and stroma on the 5th day of pregnancy compared to other pregnancy days. SENP1 was high on the 4th but low on the 5th day of pregnancy. On the 6th and 8th days of pregnancy, expressions of SUMO1 and SENP1 were decreased, while the amount of UBC9 was similar to other days of pregnancy. According to ELISA, E₂ reached its highest level on the 4th day of pregnancy, and P₄ reached its highest level on the 8th day of pregnancy. SUMO1, SENP1, and UBC9 are expressed at different levels in the uterus and implantation sites during early pregnancy. Our findings suggest that the sumoylation mechanism may play a role in the implantation and decidualization processes of mice.

Keywords: Mouse; SENP1; SUMO1; UBC9; Uterus.

Fig. 1

SUMO1 immunohistochemistry in the luminal epithelium, the glandular epithelium, and the stroma of the uterus, implantation, and inter-implantation sites of the experimental groups. le Luminal epithelium, ge Glandular epithelium, s Stroma, e Embryo, pdz Primary decidual zone, sdz Secondary decidual zone. For figures LE, GE, and S; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy, d: inter-implantation sites of the 5th day of pregnancy, e: 6th day of pregnancy. Scale bars: 1st line 150 μm, second, third, and fourth lines 50 μm.

Fig. 2

SENP1 immunohistochemistry in the luminal epithelium, the glandular epithelium, and the stroma of the uterus, implantation, and inter-implantation sites of the experimental groups. le Luminal epithelium, ge Glandular epithelium, s Stroma, e Embryo, pdz Primary decidual zone, sdz Secondary decidual zone. For figures LE, GE, and S; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy, d: inter-implantation sites of the 5th day of pregnancy. Scale bars: 1st line 150 μm, second, third, and fourth lines 50 μm.

Fig. 3

UBC9 immunohistochemistry in the luminal epithelium, the glandular epithelium, and the stroma of the uterus, implantation, and inter-implantation sites of the experimental groups. le Luminal epithelium, ge Glandular epithelium, s Stroma, e Embryo, pdz Primary decidual zone, sdz Secondary decidual zone. For figures LE, GE, and S; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy, d: inter-implantation sites of the 5th day of pregnancy. Scale bars: 1st line 150 μm, second, third, and fourth lines 50 μm.

Fig. 4

SUMO1 Western Blot in the uterus and implantation sites of all experimental groups and analysis; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy, d: inter-implantation sites of the 5th day of pregnancy, e: 6th day of pregnancy.

Fig. 5

SENP1 Western Blot in the uterus and implantation sites of all experimental groups and analysis; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy, d: inter-implantation sites of the 5th day of pregnancy, e: 6th day of pregnancy.

Fig. 6

UBC9 Western Blot in the uterus and implantation sites of all experimental groups and analysis; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy.

Fig. 7

Estrogen levels in the uterus and implantation sites of all experimental groups and analysis; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy.

Fig. 8

Progesterone levels in the uterus and implantation sites of all experimental groups and analysis; different letters indicate a significant difference compared to that group; a: 1st day of pregnancy, b: 4th day of pregnancy, c: implantation sites of the 5th day of pregnancy.

Fig. 9

Schematic illustration of the interaction between SUMO1, SENP1, and UBC9 proteins during the peri-implantation period in the mouse uterus. The diagram integrates hormonal fluctuations (E₂ and P₄), protein expression dynamics across implantation days (1st, 4th, 5th, 6th and 8th ), and their potential roles in implantation, decidualization, and angiogenesis. Red arrows represent inhibition expression; T-bars represent decreased expression.