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Glomerular mesangial cells (MCs) proliferate and produce extracellular matrix proteins in many progressive renal diseases. Recently, histone deacetylase inhibitors (HDIs) were shown to have antiproliferative and antifibrogenic effects in some in vitro and in vivo models. Using the [3H]-thymidine incorporation test, we have found that the HDI trichostatin A (TSA) effectively inhibits MC growth at nontoxic nanomolar concentrations. Similarly, the HDI valproic acid also inhibited MCs proliferation. Cell-cycle analysis indicated an arrest in [G.sub.0]/[G.sub.1] phase in response to TSA, which was accompanied by elevation in synthesis of the cyclin-dependent kinase inhibitors (CDKIs) p21/Waf1 and p27/Kip1. TSA treatment suppressed m-smooth muscle actin, transforming growth factor-[beta]1, and collagen protein synthesis by MCs and induced myofibroblast-like appearance of proliferating MCs. In the in vivo model of the anti-Thyl.1-induced glomemlonephritis, TSA and valproic acid treatments significantly suppressed proteinuria. Collectively, these data suggest a therapeutic potential for HDIs in the treatment of mesangial proliferative diseases and glomemlosclerosis. mesangial cells; proliferation; trichostatin A; valproic acid; smooth muscle [alpha]-actin; collagen IV doi: 10.1152/ajprenal.00107.2009

One of the most common side effects of treatment with cyclosporin A (CsA) is hypertrichosis. This study shows that calcineurin activity is associated with hair keratinocyte differentiation in vivo, affecting nuclear factor of activated T cells (NFAT1) activity in these cells. Treatment of nude or C57BL/6 depilated normal mice with CsA inhibited the expression of keratinocyte terminal differentiation markers associated with catagen, along with the inhibition of calcineurin and NFAT1 nuclear translocation. This was associated with induction of hair growth in nude mice and retardation of spontaneous catagen induction in depilated normal mice. Furthermore, calcineurin inhibition blocked the expression of [p21.sup.waf/cip1] and[ p27.sup.kip1], which are usually induced with differentiation. This was also associated with an increase in interleukin-1[alpha] expression (nude mice), a decrease in transforming growth factor-[beta] (nude and normal mice), and no change in keratinocyte growth factor expression in the skin. Retardation of catagen in CsA-treated mice was accompanied by significant alterations in apoptosis-related gene product expression in hair follicle keratinocytes. The ratio of the anti-apoptotic Bcl-2 to proapoptotic Bax expression increased, and expression of p53 and interleukin-1[beta] converting enzyme activity decreased. These data provide the first evidence that calcineurin is functionally active in follicular keratinocytes and that inhibition of the calcineurin-NFAT1 pathway in these cells in vivo by CsA enhances hair growth. catagen; epithelial cells; terminal differentiation; apoptosis; hypertrichosis; nuclear factor of activated T cells

Delayed branching of endothelial capillary-like cords in glycated collagen I is mediated by early induction of PAI-1. Am J Physiol Renal Physiol 281: F71-F80, 2001.--Development of micro- and macrovascular disease in diabetes mellitus (DM) warrants a thorough investigation into the repertoire of endothelial cell (EC) responses to diabetic environmental cues. Using human umbilical vein EC (HUVEC) cultured in three-dimensional (3-D) native collagen I (NC) or glycated collagen I (GC), we observed capillary cord formation that showed a significant reduction in branching when cells were cultured in GC. To gain insight into the molecular determinants of this phenomenon, HUVEC subjected to GC vs. NC were studied using a PCR-selected subtraction approach. Nine different genes were identified as up- or downregulated in response to GC; among those, plasminogen activator inhibitor-1 (PAI-1) mRNA was found to be upregulated by GC. Western blot analysis of HUVEC cultured on GC showed an increase in PAI-1 expression. The addition of a neutralizing anti-PAI-1 antibody to HUVEC cultured in GC restored the branching pattern of formed capillary cords. In contrast, supplementation of culture medium with the constitutively active PAI-1 reproduced defective branching patterns in HUVEC cultured in NC. Ex vivo capillary sprouting in GC was unaffected in PAI-1 knockout mice but was inhibited in wild-type mice. This difference persisted in diabetic mice. In conclusion, the PCR-selected subtraction technique identified PAI-1 as one of the genes characterizing an early response of HUVEC to the diabetic-like interstitial environment modeled by GC and responsible for the defective branching of endothelial cells. We propose that an upregulation of PAI-1 is causatively linked to the defective formation of capillary networks during wound healing and eventual vascular dropout characteristic of diabetic nephropathy. glycation end products; extracellular matrix; diabetic nephropathy; angiogenesis; cDNA differential display; plasminogen activator inhibitor-1

Glomerular hemodynamics in severe obesity. Am J Physiol Renal Physiol 278: F817-F822, 2000.--Differential solute clearances were used to characterize glomerular function in 12 nondiabetic subjects with severe obesity (body mass index [is greater than] 38). Nine healthy subjects served as the control group. In the obese group, glomerular filtration rate (GFR) and renal plasma flow (RPF) exceeded the control value by 51 and 31%, respectively. Consequently, filtration fraction increased. The augmented RPF suggested a state of renal vasodilatation involving, mainly or solely, the afferent arteriole. Albumin excretion rate and fractional albumin clearance increased by 89 and 78%, respectively. Oral glucose tolerance tests were suggestive of insulin resistance. Insulin resistance was positively correlated with GFR (r = 0.88, P [is less than] 0.001) and RPF (r = 0.72, P [is less than] 0.001). Mean arterial pressure was higher than in the control group. Fractional clearances of dextrans of broad size distribution tended to be lowered. The determinants of the GFR were estimated qualitatively by using a theoretical model of dextran transport through a heteroporous membrane. This analysis suggests that the high GFR in very obese subjects may be the result of an increase in transcapillary hydraulic pressure difference ([Delta]P). An abnormal transmission of increased arterial pressure to the glomerular capillaries through a dilated afferent arteriole could account for the augmentation in [[Delta]P]. dextran; glomerular barrier; hyperfiltration; insulin resistance; transcapillary hydraulic pressure difference