Targeting TGF-beta overexpression: maximizing the antifibrotic actions of angiotensin II blockade in anti-Thy1 glomerulonephritis

Salvia miltiorrhiza Depresses Plasminogen Activator Inhibitor-1 Production Through Inhibition of Angiotensin II

The purpose of this study was to investigate the effect of Salvia miltiorrhiza on the production of plasminogen activator inhibitor-1(PAI-1) induced by angiotensin II (Ang II) in renal mesangial cells. Rat mesangial cells were exposed to 100 nM Ang II. Meanwhile, different concentrations of Salvia miltiorrhiza injection were added to Mesangial Cells. PAI-1 mRNA was measured by semi-quantification reverse transcriptase polymerase chain reaction (RT-PCR) and PAI-1 protein by Western blotting. ELISA was used to detect the expression of transforming growth factor β1(TGF-β1) in serum free MEM medium. The level of cellular reactive oxygen species (ROS) was measured by confocal laser scanning microscopy. Salvia miltiorrhiza notably attenuated expression of PAI-1 induced by Ang II in a concentration-dependent manner. Meanwhile, it suppressed the production of TGF-β1and cellular ROS in mesangial cells. These effects were due to Salvia miltiorrhiza's ability of inhibiting the activities of angiotensin II. Therefore, Salvia miltiorrhiza can be used to retard progression of glomerular sclerosis.

ACE Inhibition in Anti-Thy1 Glomerulonephritis Limits Proteinuria but Does Not Improve Renal Function and Structural Remodeling

Background/Aims

ACE inhibitor (ACE-I) treatment effectively inhibits proteinuria and ameliorates the course of various renal diseases. In experimental glomerulonephritis, however, angiotensin II (AngII) infusion has also been shown to be renoprotective. We evaluated the long-term (28 days) course of anti-Thy1 glomerulonephritis in animals with suppressed AngII formation by ACE-I treatment.

Methods

Brown Norway rats received perindopril (2.8 mg/kg/day, n = 12), dihydropyridine calcium-antagonist amlodipine (Ca-A; 13 mg/kg/day, n = 6) or were left untreated (n = 14). All animals were monitored for blood pressure, proteinuria, and creatinine clearance after anti-Thy1 injection. Renal histology was assessed at day 7 and 28.

Results

Systolic blood pressure was equally reduced by ACE-I and Ca-A treatment. AngII suppression prevented development of proteinuria, but did not protect against glomerular microaneurysm formation or reduction in creatinine clearance. After resolution of the microaneurysms, animals with suppressed AngII production showed a modest increase in glomerulosclerosis and vasculopathic thickening of intrarenal vessels.

Conclusions

In anti-Thy1 glomerulonephritis, suppression of AngII formation does not protect against the induction of glomerular damage and is associated with mild aggravation of adverse renal fibrotic remodeling. Proteinuria, however, is effectively prevented by ACE-I treatment. Ca-A treatment did not affect the course of glomerulonephritis, indicating that ACE-I effects are blood pressure independent.

Chinese herbal formula Qilong-Lishui granule improves puromycin aminonucleoside-induced renal injury through regulation of bone morphogenetic proteins

BACKGROUND

The Chinese herbal formula Qilong-Lishui granule (QLG) is an effective natural product for treatment of renal disorder. It was composed of six Chinese herbs according to our clinical practice in the treatment of patients with kidney disease. However, molecular and cellular mechanisms of QLG are still unclear. Therefore, the objective of the current study is to investigate molecular and cellular mechanisms of QLG in puromycin aminonucleoside (PAN)-induced nephrotic syndrome.

METHOD

Wistar rats were divided into six groups of sham operation, PAN model, PAN model with high-dosage QLG (QLG-H), PAN model with median-dosage QLG (QLG-M), PAN model with low-dosage QLG (QLG-L), and PAN model with fosinopril (FP). The PAN model was induced by jugular vein injection of PAN at a dose of 5 mg/100 g body weight. Quantities of 24 h urinary protein excretion were examined on days 5, 10, 15, 20, 25 and 30. All rats were sacrificed on day 31 for blood biochemistry, kidney histology and reverse transcriptase-polymerase chain reaction analysis.

RESULTS

PAN-induced nephrotic syndrome was successfully produced in rats. Treatment of QLG significantly reduced protein excretion and blood urea nitrogen and creatinine. QLG and FP treatments also improved protein content in blood, and reduced total cholesterol and triglyceride in blood. Moreover, QLG and FP improved the damage of interstitial induced by PAN. Furthermore, CYP and FP were able to reverse BMPRII and Smad1 mRNAs abundance caused by PAN.

CONCLUSION

QLG attenuates PAN-induced kidney injury possibly through the bone morphogenetic protein signal transduction pathway.

Intrauterine growth retardation aggravates the course of acute mesangioproliferative glomerulonephritis in the rat

Intrauterine growth retardation (IUGR) aggravates the course of acute mesangioproliferative glomerulonephritis (GN) in the rat. Observational studies in children suggest that IUGR may be associated with a severe course of kidney diseases such as IgA nephropathy. We tested the hypothesis that IUGR leads to aggravation of acute mesangioproliferative GN in former IUGR rats. IUGR was induced in Wistar rats by isocaloric protein restriction in pregnant dams. Litter size was reduced to six male neonates in low protein animals (LP) and normal protein animals (NP). At 8 weeks GN was induced by injection of an anti-Thy-1.1 antibody. Rats were killed on days 4 and 14 after induction of GN and kidneys were investigated for inflammation and sclerosis using real-time polymerase chain reaction and histological methods. On day 4 after induction of GN, LP animals showed more glomerulosclerosis and tubulointerstitial lesions. On day 14, inflammatory markers (expression of monocyte chemoattractant protein 1, osteopontin, tumor necrosis factor and interleukin-6), extracellular matrix accumulation and markers of sclerosis (plasminogen activator inhibitor-1 expression, transforming growth factor-beta1 expression, score for glomerulosclerosis, glomerular deposition of collagen I and collagen IV) were more severe in LP animals. Some degree of induction of inflammatory and profibrotic markers was also present in non-nephritic LP animals. However, these rats did not display marked glomerulosclerosis or interstitial fibrosis. We conclude that after IUGR inflammatory damage is aggravated and the reparation of the kidney is impaired during the course of acute mesangioproliferative GN, leading to more sclerotic lesions.

Adrenomedullin reduces mesangial cell number and glomerular inflammation in experimental mesangioproliferative glomerulonephritis

BACKGROUND

Adrenomedullin (ADM) is a vasodilator peptide that is abundantly expressed in the kidney. ADM has antiproliferative effects on glomerular mesangial cells (MC) in vitro. Whether or not treatment with ADM can reduce MC proliferation in vivo [i.e., in mesangioproliferative glomerulonephritis (GN)] is unknown. We tested the hypothesis that ADM substitution reduces MC proliferation in GN.

METHODS

GN in rats was induced by injection of an anti-Thy-1.1 antibody. Rats received osmotic minipumps, which continuously delivered rat ADM (500 ng/hour, N = 11), or vehicle (N = 13) from day 3 to day 6 after GN induction. Rats were sacrificed 6 days after induction of GN. On kidney sections, cells staining positive for proliferating cell nuclear antigen, mesangial cells, monocytes, and apoptotic cells were counted. Parameters of inflammation and fibrosis were measured in renal cortex and sieved glomeruli by real-time polymerase chain reaction (PCR).

RESULTS

Systolic blood pressure, diuresis, albuminuria, creatinine clearance, microaneurysm formation, and mesangial matrix expansion were not influenced by ADM infusion. However, ADM treatment significantly reduced the number of MC, showed a tendency to reduce total glomerular cell proliferation, and significantly increased apoptosis. ADM-treated GN animals showed significantly less glomerular monocyte infiltration. ADM treatment normalized transforming growth factor (TGF)-beta1 mRNA expression and reduced monocyte chemoattractant protein-1 (MCP-1), osteopontin, plasminogen activator inhibitor-1 (PAI-1), collagen I, and collagen III mRNA expression significantly.

CONCLUSION

Exogenous ADM infusion reduces MC number and glomerular monocyte infiltration in the state of mesangial proliferation during acute experimental mesangioproliferative GN. These findings indicate that ADM can influence the course of mesangioproliferative GN.

Laser capture microdissection and real-time PCR for analysis of glomerular endothelin-1 gene expression in mesangiolysis of rat anti-Thy 1.1 and murine Habu Snake Venom glomerulonephritis

Molecular analysis of pathologic changes in glomeruli requires methods allowing rapid and exact detection of alterations in gene expression. Here, we analyzed endothelin-1 (ET-1) mRNA expression in mesangiolytic glomeruli during the course of a rat and murine model of mesangioproliferative glomerulonephritis (GN). A novel method combining laser capture microdissection (LCM), which permits the precise removal of selected mesangiolytic glomeruli, with a highly sensitive real-time RT-PCR technique was used. Anti-Thy 1.1. GN was introduced in male Sprague-Dawley rats (1.0 mg/kg body weight of OX-7 IV) and Habu Snake Venom GN was introduced in C57BL6 mice (habu snake venom toxin 6 mg/kg body weight IV). The degree of mesangiolysis during both GNs was analyzed using a semiquantitative scoring system. Mesangiolytic glomeruli were microdissected at different days of the diseases (day 2, 6, and 12 in anti-Thy 1.1 GN and days 1, 3, 7, and 14 in Habu Snake Venom GN) and from normal control animals. After RNA extraction and cDNA synthesis, ET-1 gene expression was measured by real-time RT-PCR. In parallel, in anti-Thy 1.1. GN ET-1 mRNA expression was analyzed using semiquantitative nonradioactive in situ hybridization; ET-1 protein expression was investigated by immunohistochemistry. Mesangiolysis peaked at day 6 in anti-Thy1.1 GN and at day 1 in Habu Snake Venom GN. Mesangiolytic glomeruli were easily microdissected on cryostat sections in both models; quantification of mRNA with RT-PCR was reliable and reproducible. Glomerular ET-1 mRNA expression increased during the course of anti-Thy 1.1 GN and Habu Snake Venom GN peaked when mesangiolysis was most pronounced. This was seen by RT-PCR after glomerular LCM and by in situ hybridization; in parallel, glomerular ET-1 protein expression was increased. Combination of LCM and RT-PCR is a reliable method for quantification of localized gene expression in isolated renal structures. The above data argue for an important role of ET-1 in pathogenesis and/or repair of mesangiolysis in experimental mesangioproliferative GN.