Aspirin prevents adhesion of T lymphoblasts to vascular smooth muscle cells.

In the development of atherosclerosis, inflammatory cells adhere to and migrate into the vascular walls by interacting with vascular smooth muscle cells. To investigate the mechanism of aspirin's anti-atherogenic activity, we examined whether aspirin inhibits the adhesion of lymphocytes to human aortic smooth muscle cells (AoSMC). Aspirin inhibited T-cell adhesion to AoSMC activated by interleukin 1beta (IL-1beta) in a dose-dependent manner. Antibodies to the adhesion molecules ICAM-1 or VCAM-1, but not to E-selectin, prevented T-cell adhesion. ICAM-1 and VCAM-1 expression stimulated by IL-1beta was reduced by the treatment with aspirin, whereas the expression of E-selectin was unaffected. Nuclear factor kappaB (NF-kappaB) activity was enhanced by IL-1beta and reduced by aspirin, indicating that decreased ICAM-1 and VCAM-1 expression was due to reduced NF-kappaB activity.Thus, aspirin inhibits the adhesion of Jurkat T cells to IL-1beta-activated AoSMC by reducing NF-kappaB activity and decreasing expression of ICAM-1 and VCAM-1, and may prevent the development of atherosclerosis.

Klotho protein promotes adipocyte differentiation.

Mice with homozygous disruption of the klotho exhibit multiple age-related disorders and have barely detectable amounts of white adipose tissue. Although klotho expression in cultured adipocytes has been reported, little is known about its function in adipocytes. In the present study, we investigated the role of klotho on adipocyte differentiation. Adipocyte differentiation was induced by incubation of confluent 3T3-L1 cells with insulin, dexamethasone, and 1-methyl-3-isobutyl-xanthin. Klotho-siRNA and expression vector were produced for klotho suppression and overexpression, respectively. Klotho protein was purified for determination of the hormonal effect of klotho. Klotho mRNA and protein expression increased up to the 3rd d of differentiation. A peroxisome proliferator-activated receptor-gamma agonist increased klotho expression during the early period of adipocyte differentiation. The mRNA expression of adipocyte differentiation markers, such as CCAAT/enhancer-binding protein (C/EBP)alpha, C/EBPbeta, C/EBPdelta, peroxisome proliferator-activated receptor-gamma, and fatty acid binding protein 4, was decreased by klotho suppression, and increased 1.9- to 3.8-fold by klotho overexpression. The results of Oil Red O staining also suggested that klotho overexpression promoted adipocyte differentiation. Klotho protein stimulation resulted in a 2.4- to 4.6-fold increase in mRNA expression of differentiation markers compared with control, and the time course depended on adipocyte induction status. Western blot analysis showed that protein levels of C/EBPalpha and C/EBPdelta were increased by Klotho protein stimulation. These results suggest that klotho works as a hormonal factor to promote adipocyte differentiation in the early days, during the period of transient proliferation in the differentiation process, and that klotho may play an essential role in adipocyte differentiation.

Anti-apoptotic and anti-senescence effects of Klotho on vascular endothelial cells.

Klotho-mutated mice manifest multiple age-related disorders that are observed in humans. A recent study suggested that Klotho protein might function as an anti-aging hormone in mammals. Because it has been reported that apoptosis and senescence in vascular endothelial cells are closely related to the progression of atherosclerosis, we investigated Klotho's ability to interfere with apoptosis and cellular senescence in human umbilical vascular endothelial cells (HUVEC). Klotho overexpression decreased H(2)O(2)-induced apoptosis in COS-1 cells and Jurkat cells. Klotho protein also reduced H(2)O(2)- and etoposide-induced apoptosis in HUVEC. Caspase-3 and caspase-9 activity was lower in Klotho-treated HUVEC than in control cells. Senescence-associated beta-gal staining showed that Klotho protein interferes with H(2)O(2)-induced premature cellular senescence. The expression of p53 and p21 was lower in Klotho-treated cells. Our study suggests that Klotho acts as a humoral factor to reduce H(2)O(2)-induced apoptosis and cellular senescence in vascular cells.

[Angiotensin type 1 receptor blocker reduced proteinuria in patients of focal glomerular sclerosis].

We report three cases of focal glomerular sclerosis (FGS) with proteinuria that improved with the administration of angiotensin type 1 receptor blocker (ARB, losartan or valsartan). These three patients were a 41-year-old male (case 1), a 22-year-old male (case 2) and a 47-year-old male (case 3), who showed proteinuria, renal dysfunction, and hyperlipidemia. In case 1, proteinuria and renal dysfunction were improved by losartan administration and low protein diet therapy. In case 2, losartan with steroid and immunosuppressant led to the complete remission of proteinuria, improvement of renal dysfunction and reduction of the glomerular injury score from repeat biopsy specimen by approximately 20%. In case 3, proteinuria was reduced by valsartan administration with steroid and immunosuppressant therapy. ARB treatment with steroid and immunosuppressant might be more effective on the reduction of proteinuria in FGS patients.

Klotho protein activates the PKC pathway in the kidney and testis and suppresses 25-hydroxyvitamin D3 1alpha-hydroxylase gene expression.

Homozygous Klotho mutant (kl-/-) mice exhibit a variety of phenotypes resembling human aging, including arteriosclerosis, infertility, skin atrophy, osteoporosis, and short life span. Calcium abnormality, one of the phenotypes in kl-/- mice, is thought to be due to the elevated gene expression of 25-hydroxyvitamin D3 1alpha-hydroxylase in the kidney. We studied 25-hydroxy-vitamin D3 1alpha-hydroxylase gene expression using a Klotho plasmid that we had previously constructed for Klotho protein production. It was found that Klotho protein medium upregulated cAMP and the PKC pathway, and suppressed 25-hydroxyvitamin D3 1alpha-hydrox-ylase in kidney cells. However, both cAMP and PKC are known to elevate 25-hydroxyvitamin D3 1alpha-hydroxylase gene expression, therefore, another unknown calcium regulation pathway using Klotho protein medium might exist. Furthermore, we found that activation of the PKC pathway by Klotho was observed only in the kidney and testis, where the Klotho gene is expressed, although activation of the cAMP pathway was observed in any kind of cell. These data suggest that calcium regulation through 25-hydroxyvitamin D3 1alpha-hydroxylase by Klotho depends on non-cAMP and a non-PKC pathway and that the Klotho protein may have different signaling pathways, depending on the Klotho gene expression in different cells and organs.