Cyclic Expression Patterns Research Articles

Altered cyclic expression of epithelial Na+ channel subunits and cystic fibrosis transmembrane conductance regulator in mouse endometrium by a low sodium diet.

Epithelial Na+ channel (ENaC) and cystic fibrosis transmembrane conductance (CFTR) have been shown to exhibit cyclic expression patterns in the uterus and demonstrated to play important roles in regulating uterine fluid absorption and secretion. The present study investigated the effect of a low Na+ diet on the cyclic expression of uterine ENaC subunits and CFTR in mice. Ten to 12 weeks old ICR mice with synchronized estrus cycle were fed with a low sodium diet for at least 2 weeks and the mRNA level of these ion channels was examined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Functional channel activities in primary cultures of endometrial epithelia were assessed by the short-circuit current (Isc) technique. The characteristic cyclic expression of ENaC subunits throughout the estrus cycle remained unchanged but their expression levels towards the diestrus stage were drastically elevated. The cyclic expression pattern of CFTR was disrupted with suppressed expression throughout the cycle. Isc measurements showed that treatment of cultured endometrial epithelial cells with aldosterone, the major hormone expected to be elevated during the low sodium diet, resulted in prominent increase in ENaC channel activity. The altered cyclic expression of uterine ENaC and CFTR by a low sodium diet suggests that these ion channels may be affected by elevated circulating aldosterone, which may disrupt reproductive events in the uterus.

Contralateral non-operated nerve to transected rat sciatic nerve shows increased expression of IL-1β, TGF-β1, TNF-α, and IL-10

Recent reports indicate that after a peripheral nerve injury, the uninjured contralateral nerve is also affected. Because cytokines play an important role in the peripheral nerve injury, we studied the expression of five different mRNAs (interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), transforming growth factor-β1 (TGF-β1) and interleukin-4 (IL-4)) in the contralateral, non-operated, left sciatic nerve when the right rat sciatic nerve was transected. This study extended up to 42 days after the transection. No IL-4 expression was noted. During the first 3 days, high expression of the other studied cytokines was noted in the endoneurium. At day 7, the expression diminished to the control levels. After this, a cyclic expression pattern appeared, which was most pronounced in the endoneurium at 35 days. We also show that the expression pattern in the endoneurium is different from that in the surrounding epi- and perineurium. Also, our present study shows clearly that contralateral nerves are poor controls after injury.

Cyclic expression of mRNA transcripts for connective tissue components in the mouse ovary.

In the ovary, differentiation of germinal cells into primordial follicles, functional ovulatory follicles and corpus luteum, all take place in a connective tissue matrix. We postulated that extracellular matrix (ECM) of the ovary participates actively in ovarian functions. To test this, the mRNA levels for several ECM components were determined in the mouse ovary at six distinct stages of the 4-day oestrous cycle. Northern analysis revealed statistically significant cyclic expression patterns for the mRNAs coding for type III, IV and VI collagens as well as for the small proteoglycan, biglycan, and for syndecan-1 and osteonectin. The cyclic changes observed in the mRNAs for these structural components exceeded those for matrix metalloproteinases (MMP)-2, -9 and -13, and for tissue inhibitors of matrix metalloproteinases (TIMP)-1, -2 and -3, where the changes were not statistically significant, despite their apparent role in ECM remodelling in the ovary. These observations support the hypothesis that cyclic changes in the production and degradation of ECM are part of normal ovarian function connected with follicular maturation, rupture and corpus luteum formation.

Fas ligand, Fas antigen and Bcl-2 expression in human endometrium during the menstrual cycle.

In this study, we investigate Fas ligand expression in the human endometrium during the menstrual cycle in relation to Fas antigen and Bcl-2 expression, using immunoelectron microscopy and Western blotting. Endometrial samples were obtained from 54 pre-menopausal non-pregnant women who underwent laparotomies for benign diseases. The Fas ligand, as well as the Fas antigen, were expressed on the surface of endometrial glandular cells throughout the menstrual cycle, whereas Bcl-2 showed a cyclic expression pattern, peaking during the late proliferative phase. A noteworthy finding was that both the Fas ligand and the Fas antigen were localized on Golgi apparatuses and vesicles, in addition to the cell membranes, during the late proliferative phase. These results indicate that the Fas ligand and Fas antigen which are localized on Golgi apparatus and vesicles during the late proliferative phase are incorporated into the cell membranes during the secretory phase, and are co-expressed on the cell membranes of endometrial glands throughout the menstrual cycle. The factors regulating Fas-mediated apoptosis in the human endometrium, including the level of expression of the Fas ligand and Bcl-2 are discussed.