Muthi Ikawati

Abnormal development of placenta in HtrA1-deficient mice

Abnormal levels of High temperature requirement A1 (HtrA1) protein have been repeatedly observed in sera and placentas of preeclampsia patients. To understand the functions of HtrA1 in placentation and in the etiology of preeclampsia, we established HtrA1(-/-) mice. HtrA1(-/-) mice show intrauterine growth retardation, and their placentas are small due to a reduced size of the junctional zone and aberrant vascularization in the labyrinth at the mid-gestation stage. HtrA1 is expressed by Tpbpa-positive trophoblast precursors in the outer ectoplacental cone and junctional zone from embryonic day 7.5 to 10.5. In the HtrA1(-/-) placenta, Tpbpa-positive cell precursors are decreased in the early stage. Spongiotrophoblasts and glycogen trophoblast cells, both of which differentiate from Tpbpa-positive precursors, are consequently decreased in the junctional zone. Fewer spiral artery-associated trophoblast giant cells, another cell type derived from Tpbpa-positive precursors, invade the decidua and associate with maternal arteries in the HtrA1(-/-) placenta than in the wild type placenta. Maternal arteries in the HtrA1(-/-) decidua have narrower lumens, thicker arterial walls, and more vascular smooth muscle cells remaining in the walls than those in the wild type decidua, indicating impaired remodeling of maternal arteries. These results indicate that HtrA1 plays important roles in the differentiation of trophoblasts from Tpbpa-positive precursors in the ectoplacental cone. Insufficient levels of HtrA1 cause poor placental development and intrauterine growth retardation, due to aberrant trophoblast differentiation and consequent defects in maternal artery remodeling, and may contribute to the onset of preeclampsia.

Immunomodulatory Effects of Ethanolic Extract of Thyphonium flagelliforme (Lodd) Blume in Rats Induced by Cyclophosphamide

The present study aimed to examine the immunomodulatory effect of ethanolic extract of Typhonium flagelliforme (Lodd) Blume in cyclophosphamide-treated rats. The immunomodulatory effects were determined by lymphocytes proliferation, phagocytic activity of macrophages, plasma cytokines of tumor necrosis factor-α, interleukin-1α, interleukin-10 levels, and killer T cells (CD8+ T cells) counts. The results showed that the administration of ethanolic extract of T flagelliforme reduced immunosupessive effect on lymphocyte proliferation, increase the number and phagocytic activity of macrophages in cyclophosphamide-treated rats. Moreover, the ethanolic extract of T flagelliforme also significantly (P < .05) improved the immune system activities especially the proliferation of CD8+T cells and reduced the suppressive effects on cytokines such as tumor necrosis factor-α and interleukin-1α. In conclusion, the ethanolic extract of T flagelliforme has immunomodulatory properties in cyclophosphamide-treated rats. The results suggest that T flagelliforme can reduce immunosuppresive effect caused by a chemotherapeutic agent.

Loss of HtrA1 serine protease induces synthetic modulation of aortic vascular smooth muscle cells

Homozygous mutations of human HTRA1 cause cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). HtrA1-/- mice were examined for arterial abnormalities. Although their cerebral arteries were normal, the thoracic aorta was affected in HtrA1-/- mice. The number of vascular smooth muscle cells (VSMCs) in the aorta was increased in HtrA1-/- mice of 40 weeks or younger, but decreased thereafter. The cross-sectional area of the aorta was increased in HtrA1-/- mice of 40 weeks or older. Aortic VSMCs isolated from HtrA1-/- mice rapidly proliferated and migrated, produced high MMP9 activity, and were prone to oxidative stress-induced cell death. HtrA1-/- VSMCs expressed less smooth muscle α-actin, and more vimentin and osteopontin, and responded to PDGF-BB more strongly than wild type VSMCs, indicating that HtrA1-/- VSMCs were in the synthetic phenotype. The elastic lamina was disrupted, and collagens were decreased in the aortic media. Calponin in the media was decreased, whereas vimentin and osteopontin were increased, suggesting a synthetic shift of VSMCs in vivo. Loss of HtrA1 therefore skews VSMCs toward the synthetic phenotype, induces MMP9 expression, and expedites cell death. We propose that the synthetic modulation is the primary event that leads to the vascular abnormalities caused by HtrA1 deficiency.