Non-muscle myosin-II-B filament regulation of paracellular resistance in cervical epithelial cells is associated with modulation of the cortical acto-myosin

Characterization of RAGE and CK2 Expressions in Human Fetal Membranes

At the feto-maternal interface, fetal membranes (FM) play a crucial role throughout pregnancy. FM rupture at term implicates different sterile inflammation mechanisms including pathways activated by the transmembrane glycoprotein receptor for advanced glycation end-products (RAGE) belonging to the immunoglobulin superfamily. As the protein kinase CK2 is also implicated in the inflammation process, we aimed to characterize the expressions of RAGE and the protein kinase CK2 as a candidate regulator of RAGE expression. The amnion and choriodecidua were collected from FM explants and/or primary amniotic epithelial cells throughout pregnancy and at term in spontaneous labor (TIL) or term without labor (TNL). The mRNA and protein expressions of RAGE and the CK2α, CK2α', and CK2β subunits were investigated using reverse transcription quantitative polymerase chain reaction and Western blot assays. Their cellular localizations were determined with microscopic analyses, and the CK2 activity level was measured. RAGE and the CK2α, CK2α', and CK2β subunits were expressed in both FM layers throughout pregnancy. At term, RAGE was overexpressed in the amnion from the TNL samples, whereas the CK2 subunits were expressed at the same level in the different groups (amnion/choriodecidua/amniocytes, TIL/TNL), without modification of the CK2 activity level and immunolocalization. This work paves the way for future experiments regarding the regulation of RAGE expression by CK2 phosphorylation.

Estrogen modulation of epithelial permeability in cervical-vaginal cells of premenopausal and postmenopausal women

OBJECTIVE

To understand how menopause affects estrogen regulation of epithelial permeability.

DESIGN

Experimental study using human normal epithelial vaginal-ectocervical cells obtained from premenopausal and postmenopausal women. Endpoints were paracellular permeability (determined in terms of the resistance of the lateral intercellular space [RLIS] and tight junctions [RTJ]); cellular G-actin; nonmuscle myosin type II-B (NMMII-B) filamentation and magnesium-adenosine triphosphatase activity; and occludin expression (in terms of expression of the functional 65-kd and truncated 50-kd forms).

RESULTS

Estrogen induced an early transient decrease in RLIS that correlated in time with increases in cellular G-actin and NMMII-B magnesium-adenosine triphosphatase activity and with decreases in NMMII-B filamentation and a slower decrease in RTJ that correlated with up-regulation of the 50-kd form of occludin. Estrogen modulation of G-actin NMMII-B and occludin could be described in terms of interaction with the estrogen receptor mechanism. The potency of estrogen effects was similar in cells of premenopausal and postmenopausal women, but the effects occurred earlier in cells of premenopausal women. RLIS returned to baseline faster in cells of postmenopausal women, and the effect was associated with faster reversal of estrogen changes in NMMII-B despite the continued presence of estrogen in the culture medium, suggesting that desensitization of the actin-myosin effects to estrogen actions occur distal to the estrogen receptor.

CONCLUSIONS

The results suggest that the transient estrogen decrease in RLIS is mediated by modulation of actomyosin, and it is affected by the aging process. In contrast, the late persistent decrease in RTJ is mediated by occludin degradation and is unrelated to aging.