Dexamethasone induces aberrant macrophage immune function and apoptosis

Glucocorticoids (GCs) are known potent clinical drugs, however, their mode of action is still complex and debatable. Macrophages are the most important target of GCs and play a key role in tumor immunity in vivo, but their relationship is also controversial. In the present study, the lentivirus system was used to overexpress and knock down the level of transcription factor Krüppel-like factor 9 (KLF9). The results revealed that dexamethasone (Dex) induced ROS generation and mitochondria-dependent apoptosis in RAW 264.7 cells via the KLF9. In addition, overexpression of KLF9 significantly increased apoptosis of RAW 264.7 cells. Notably, ELISA assay revealed that increased expression of KLF9 inhibited LPS-induced COX-2 expression and reduced COX-2-derived prostaglandin E2 and pro-inflammatory cytokine secretion. Furthermore, a co-culture system was used to reveal that overexpression of KLF9 in RAW 264.7 cells promoted HepG2 cell survival. In summary, it is reported that KLF9 promoted apoptosis of proinflammatory macrophages, and suppressed the antitumor effects, which can be selectively targeted by GCs as a novel mechanism to suppress antineoplastic activity.

Thyroid hormones in fetal growth and prepartum maturation

The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are essential for normal growth and development of the fetus. Their bioavailability in utero depends on development of the fetal hypothalamic-pituitary-thyroid gland axis and the abundance of thyroid hormone transporters and deiodinases that influence tissue levels of bioactive hormone. Fetal T4 and T3 concentrations are also affected by gestational age, nutritional and endocrine conditions in utero, and placental permeability to maternal thyroid hormones, which varies among species with placental morphology. Thyroid hormones are required for the general accretion of fetal mass and to trigger discrete developmental events in the fetal brain and somatic tissues from early in gestation. They also promote terminal differentiation of fetal tissues closer to term and are important in mediating the prepartum maturational effects of the glucocorticoids that ensure neonatal viability. Thyroid hormones act directly through anabolic effects on fetal metabolism and the stimulation of fetal oxygen consumption. They also act indirectly by controlling the bioavailability and effectiveness of other hormones and growth factors that influence fetal development such as the catecholamines and insulin-like growth factors (IGFs). By regulating tissue accretion and differentiation near term, fetal thyroid hormones ensure activation of physiological processes essential for survival at birth such as pulmonary gas exchange, thermogenesis, hepatic glucogenesis, and cardiac adaptations. This review examines the developmental control of fetal T4 and T3 bioavailability and discusses the role of these hormones in fetal growth and development with particular emphasis on maturation of somatic tissues critical for survival immediately at birth.

Pitting type of pretibial edema in a patient with silent thyroiditis successfully treated by angiotensin II receptor blockade

Patient: Female, 56

Final Diagnosis: Thyroiditis – silent

Symptoms: Palpitations • pretibial pitting edema • short of breath • sweating

Medication: —

Clinical Procedure: —

Specialty: Endocrinology and Metabolic

Decreased expression of a novel prostaglandin transporter, OAT-PG, facilitates renocortical PGE2 accumulation during rat pregnancy

BACKGROUND

Prostaglandin (PG)-specific organic anion transporter (OAT-PG) is a recently identified renal transporter involved in the local clearance of prostaglandin E2 (PGE2). Since the renal biosynthesis of PGE2 is not increased during pregnancy, this transporter expression would affect the gestational changes in the renal PGE2 content.

METHODS

Kidneys from rats at different gestational stages were used to examine gestational changes in the renocortical PGE2 concentration. The renal expression of OAT-PG and the enzymes for PGE2 synthesis was also examined sequentially, together with the gestational changes in renal renin production.

RESULTS

The renocortical PGE2 concentration was significantly increased during midterm to late pregnancy, with a maximum increase of 47.6 ± 11.5% from the virgin value. Although the expression of the enzymes, such as cyclooxygenases and PG synthases, was not increased, that of OAT-PG was significantly decreased throughout pregnancy, inversely correlating with changes in the renocortical PGE2 concentration. Renal renin production was significantly increased during pregnancy.

CONCLUSION

This study demonstrated for the first time that the tissue PGE2 concentration was increased in pregnant rat kidneys, which may be associated with the gestational rise in glomerular filtration rate. The decreased expression of OAT-PG was thought to be responsible for the increased tissue PGE2 content.

Maternal undernourished fetal kidneys exhibit differential regulation of nephrogenic genes including downregulation of the Notch signaling pathway

Maternal undernutrition results in offspring nephron number reduction and hypertension that are hypothesized to begin as compensatory changes in fetal gene expression during gestation. To evaluate mechanisms of dysregulated nephrogenesis, pregnant Sprague Dawley rats were 50% food restricted from embryonic day (E) 10 to E20. At E20, fetal male kidneys were examined by microarray analysis. A total of 476 differentially expressed transcripts were detected including those regulating development and differentiation, mitosis and cell cycle, chromatin assembly, and steroid hormone regulation. Differentially regulated genes were detected in MAPK/ERK, Wnt, and Notch signaling pathways. Validation of the microarray results was performed for the Notch signaling pathway, an important pathway in nephron formation. Protein expression of Notch pathway factors by Western blotting showed significantly decreased Notch2 and downstream effector Hey1 protein expression, while Ctbp1 co-repressor was increased. These data together show that maternal undernutrition results in developmental disruption in fetal nephrogenesis gene expression signaling.