P-selectin deficiency promotes liver senescence in sickle cell disease mice.

Sickle cell disease (SCD) is caused by a homozygous mutation in the ß-globin gene, which leads to erythrocyte sickling, vasoocclusion, and intense hemolysis. P-selectin inhibition has been shown to prevent vasoocclusive events in patients with SCD; however, the chronic effect of P-selectin inhibition in SCD remains to be determined. Here, we used quantitative liver intravital microscopy in our recently generated P-selectin-deficient SCD mice to show that chronic P-selectin deficiency attenuates liver ischemia but fails to prevent hepatobiliary injury. Remarkably, we find that this failure in resolution of hepatobiliary injury in P-selectin-deficient SCD mice is associated with the increase in cellular senescence and reduced epithelial cell proliferation in the liver. These findings highlight the importance of investigating the long-term effects of chronic P-selectin inhibition therapy on liver pathophysiology in patients with SCD.

Intravital imaging reveals inflammation as a dominant pathophysiology of age-related hepatovascular changes.

Aging is the most significant risk factor for the majority of chronic diseases, including liver disease. The cellular, molecular, and pathophysiological mechanisms that promote age-induced hepatovascular changes are unknown due to our inability to visualize changes in liver pathophysiology in live mice over time. We performed quantitative liver intravital microscopy (qLIM) in live C57BL/6J mice to investigate the impact of aging on the hepatovascular system over a 24-mo period. qLIM revealed that age-related hepatic alterations include reduced liver sinusoidal blood flow, increased sinusoidal vessel diameter, and loss of small hepatic vessels. The ductular cell structure deteriorates with age, along with altered expression of hepatic junctional proteins. Furthermore, qLIM imaging revealed increased inflammation in the aged liver, which was linked to increased expression of proinflammatory macrophages, hepatic neutrophils, liver sinusoidal endothelial cells, senescent cells, and procoagulants. Finally, we detected elevated NF-κB pathway activity in aged livers. Overall, these findings emphasize the importance of inflammation in age-related hepatic vasculo-epithelial alterations and highlight the utility of qLIM in studying age-related effects in organ pathophysiology.

Defenestrated endothelium delays liver-directed gene transfer in hemophilia A mice.

Hemophilia A is an inherited bleeding disorder caused by defective or deficient coagulation factor VIII (FVIII) activity. Until recently, the only treatment for prevention of bleeding involved IV administration of FVIII. Gene therapy with adeno-associated vectors (AAVs) has shown some efficacy in patients with hemophilia A. However, limitations persist due to AAV-induced cellular stress, immunogenicity, and reduced durability of gene expression. Herein, we examined the efficacy of liver-directed gene transfer in FVIII knock-out mice by AAV8-GFP. Surprisingly, compared with control mice, FVIII knockout (F8TKO) mice showed significant delay in AAV8-GFP transfer in the liver. We found that the delay in liver-directed gene transfer in F8TKO mice was associated with absence of liver sinusoidal endothelial cell (LSEC) fenestration, which led to aberrant expression of several sinusoidal endothelial proteins, causing increased capillarization and decreased permeability of LSECs. This is the first study to link impaired liver-directed gene transfer to liver-endothelium maladaptive structural changes associated with FVIII deficiency in mice.

Antioxidant activity of extracts from Euryale ferox seed.

Euryale ferox has been widely used in traditional oriental medicine to treat a variety of illness. However, very little is known about the cellular actions by which this plant mediates its therapeutic effects. Various aspects of antioxidant activity were evaluated in total extracts and fractions derived from Euryale ferox. Total extracts (IC50 5.6 microg/ml) showed relatively high level radical scavenging activity toward 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and also enhanced viability of Chinese hamster lung fibroblast (V79-4) cells under exposure to oxidative agents. Upon further fractionation, the highest levels of DPPH radical scavenging and lipid peroxidation inhibitory activities were found in the ethyl acetate and butanol fractions. The ethyl acetate fractions, the butanol fractions, and total extracts of Euryale ferox also dose-dependently enhanced the activities of superoxide dismutase, catalase and glutathione peroxidase in V79-4 cells. Of these three antioxidant enzymes, glutathione peroxidase activity was most strongly induced. Taken together, our findings show that Euryale ferox contains a significant antioxidant activity and that specific components in the ethyl acetate and butanol fractions may play an important role in mediating these antioxidant properties.

Antioxidant and anticancer activity of extract from Betula platyphylla var. japonica.

The antioxidant and anticancer properties of a medicinal plant, Betula platyphylla var. japonica were investigated. The total methanol extract of B. platyphylla var. japonica had protective effects against hydrogen peroxide (H2O2) in the Chinese hamster lung fibroblast (V79-4) cell line and induced apoptotic cell death in human promyelocytic leukemia (HL-60) cells, a cancer cell line. B. platyphylla var. japonica extract significantly increased cell viability against H2O2. The extract also showed high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (IC50 2.4 microg/ml) and lipid peroxidation inhibitory activity (IC50 below 4.0 microg/ml). Furthermore, B. platyphylla var. japonica extract reduced the number of V79-4 cells arrested in G2/M in response to H2O2 treatment and increased the activities of several cellular antioxidant enzymes, including superoxide dismutase, catalase and glutathione peroxidase. Treatment with B. platyphylla var. japonica extract induced cytotoxicity and apoptosis in HL-60 cells, as shown by nucleosomal DNA fragmentation, increases in the subdiploid cell population, and fluorescence microscopy. B. platyphylla var. japonica extract gradually increased the expression of pro-apoptotic Bax and led to the activation of caspase-3 and cleavage of PARP. These findings suggest that B. platyphylla var. japonica exhibits potential antioxidant and anticancer properties.

Induction of apoptosis by momordin I in promyelocytic leukemia (HL-60) cells.

We studied the effect of momordin I, a compound purified from a plant, Ampelopsis japonica, on cell proliferation and induction of apoptosis in human promyelocytic leukemia (HL-60) cells. Momordin I was cytotoxic to HL-60 cells with an IC50 of 19.0 microg/ml. The antiproliferative effects of momordin I appear to be attributable to its induction of apoptotic cell death, as momordin I induced nuclear morphology changes and internucleosomal DNA fragmentation and it increased the proportion of hypodiploid cells. Momordin I treatment also gradually decreased the expression of.the anti-apoptotic protein Bcl-2, but increased the expression of the pro-apoptotic protein Bax. In addition, momordin I treatment increased the activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase. In this study we showed that momordin I induced apoptosis of HL-60 cells by reduction of the Bcl-2:Bax ratio and by activation of caspase-3. These results provide important information towards understanding the mechanism by which momordin I induces apoptosis.

Apoptosis of mink lung epithelial cells by co-treatment of low-dose staurosporine and transforming growth factor-beta1 depends on the enhanced TGF-beta signaling and requires the decreased phosphorylation of PKB/Akt.

We demonstrate how co-treatment of low-dose staurosporine (STS) and TGF-beta1, which alone have little effect on cell death, markedly induces apoptosis in Mv1Lu mink lung epithelial cells, but not in its clonal variant R1B cells lacking functional TGF-beta signaling. This process was associated with mitochondria-dependent apoptosis and the enhanced TGF-beta/Smad signaling in Mv1Lu cells. When R1B cells were infected with adenovirus carrying wild-type ALK5, a functional TGF-beta type I receptor gene, the apoptotic cell death was significantly restored in these cells following co-treatment of low-dose STS and TGF-beta1. Treatment of Mv1Lu cells with both low-dose STS and TGF-beta1 decreased the activity of phospho-Akt, which is involved in cell survival signal. In addition, pre-treatments of PI3 kinase inhibitors, LY294002 and wortmannin, further increased the apoptosis of MvlLu cells induced by co-treatment of low-dose STS and TGF-beta1. And overexpression of constitutively active Akt (myr-Akt) using adenoviral expression system inhibited the apoptotic cell death of Mv1Lu cells by about 50% upon co-treatment of low-dose STS and TGF-beta1. These results suggest that co-treatment of low-dose STS and TGF-beta1 induces apoptosis of mink lung epithelial cells by enhancing TGF-beta signaling and in part suppressing cytoprotective signaling.