Evaluation of placental protein modifications in normotensive and spontaneously hypertensive rats

Hypertension in pregnancy is often associated to placental deficiency. Therefore several physiopathological modifications occur to sustain fetal well-being through protective mechanisms. Here, we used spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) counterpart to evaluate in late gestation (d 20) modification of placental proteins involved in adaptation to hypertension. Placenta from WKY and SHR was excised for the evaluation of protein changes by Western blot analysis and zymography. In particular, we showed in SHR placentas an increase in angiotensin receptor type 1 and a decrease in angiotensin converting enzyme. Conversely, inducible nitric oxide synthase expression was increased, while constitutive endothelial nitric oxide synthase was similar in both groups. Placentas from SHR showed a reduced protein expression in both peroxisome proliferators-activated receptors-alpha and -gamma. Pro-metalloproteinase-9 activity was not significantly modified, whereas both pro-metalloproteinase-2 and its active form present a higher activity in SHR placentas. Moreover, at the end of pregnancy, cyclooxygenase-2 expression decreased in SHR placentas. These data may provide new insights into the placental adaptive mechanisms that take place during pregnancy in SHR.     

Time-course analyses addressing the acquisition of DBA lectin reactivity in mouse lymphoid organs and uterus during the first week of pregnancy

Terminal differentiation of uterine natural killer (uNK) cells is induced in humans and mice at the time of endometrial decidualization. In mice, commitment to this lineage is first recognized at gestation day (gd)5.5 when small, non-granulated lymphocytes in the mesometrial decidua basalis become histochemically reactive with the lectin Dolichlos biflorus agglutinin (DBA). Transplantation experiments in mice have shown that the self-renewing progenitors of uNK cells are present in peripheral rather than uterine tissues. While lymphoid tissues of virgin mice lack DBA lectin reactive putative uNK cell precursors or progenitors, peripheral organs have not been systematically examined in female mice during early pregnancy while the uNK cell population is becoming established. Here we report such a study in gd0.5–7.5 random bred mice. Only mesenteric lymph nodes showed a transient gain in DBA lectin reactive lymphocytes between gd0.5 and 4.5. These cells had cytoplasmic but almost no surface DBA lectin reactivity. This study indicates that the decidual environment is unique and locally promotes DBA lectin surface expression in terminally differentiating uNK cells.     

Serum and synovial fluid IgG,IgA and IgM antigammaglobulins in rheumatoid arthritis

Antigammaglobulins of IgG, IgA and IgM classes were measured in normal individuals and in patients with osteoarthritis or rheumatoid arthritis. Serum IgG and IgA and synovial fluid IgG antigammaglobulin levels were significantly higher in patients with rheumatoid arthritis than in other individuals, with highest levels occurring in patients with positive latex fixation tests. IgM antigammaglobulins were elevated only in patients with latex positive rheumatoid arthritis. Increased serum levels of IgG, IgA and IgM antigammaglobulins were each associated with clinical findings of severe rheumatoid arthritis. Increased levels of serum and synovial fluid IgG and IgM antigammaglobulins were each associated with diminished serum and synovial fluid complement levels.     

Coordination of hypothalamic and pituitary T3 production regulates TSH expression

Type II deiodinase (D2) activates thyroid hormone by converting thyroxine (T4) to 3,5,3′-triiodothyronine (T3). This allows plasma T4 to signal a negative feedback loop that inhibits production of thyrotropin-releasing hormone (TRH) in the mediobasal hypothalamus (MBH) and thyroid-stimulating hormone (TSH) in the pituitary. To determine the relative contributions of these D2 pathways in the feedback loop, we developed 2 mouse strains with pituitary- and astrocyte-specific D2 knockdown (pit-D2 KO and astro-D2 KO mice, respectively). The pit-D2 KO mice had normal serum T3 and were systemically euthyroid, but exhibited an approximately 3-fold elevation in serum TSH levels and a 40% reduction in biological activity. This was the result of elevated serum T4 that increased D2-mediated T3 production in the MBH, thus decreasing Trh mRNA. That tanycytes, not astrocytes, are the cells within the MBH that mediate T4-to-T3 conversion was defined by studies using the astro-D2 KO mice. Despite near-complete loss of brain D2, tanycyte D2 was preserved in astro-D2 KO mice at levels that were sufficient to maintain both the T4-dependent negative feedback loop and thyroid economy. Taken together, these data demonstrated that the hypothalamic-thyroid axis is wired to maintain normal plasma T3 levels, which is achieved through coordination of T4-to-T3 conversion between thyrotrophs and tanycytes.     

Involvement of A1 adenosine receptors in the acquisition of fertilizing capacity

Ejaculated mammalian spermatozoa acquire competence to fertilize oocytes by a two-step process: capacitation followed by acrosome reaction. The biochemical and biophysical modifications occurring in vivo in the female reproductive tract can be reproduced in vitro, and previous studies have suggested a capacitative role for adenosine A(1) receptor (A(1)R). Mice with a targeted disruption of the Adora 1 gene (A(1)R-/- mice) provide a useful model for better understanding the role of the A(1)R in fertility. Murine spermatozoa express A(1)R in the head, neck, midpiece region, and tail. The number of capacitated spermatozoa incubated in human tubal fluid was significantly reduced in A(1)R-/- compared with A(1)R+/+ and A(1)R+/- spermatozoa. The difference between A(1) R+/+ and A(1)R-/- mouse spermatozoa was mainly in the time necessary to reach the maximum percentage of capacitation. A(1)R+/+ murine sperm obtained the full state of capacitation within 90 minutes whereas A(1)R-/- sperm required 240 minutes. Caffeine, a known antagonist of A(1) and A(2A) adenosine receptors, lowered the number of capacitated sperm and affected the time of capacitation in a dose-dependent manner, mimicking the effects of the lack of A(1) receptors. Although number, motility, and viability of A(1)R-/- murine sperm was not significantly different from A(1)R+/+ mouse spermatozoa, a significant reduction of the number of pups produced by A(1)R-/- male mice suggests that A(1) receptors must be fully operative to accomplish the optimal degree of capacitation and thereby fertilization.