transforming-growth-factor-alpha and Kidney-Diseases

Topics: Animals; Biomarkers; Bone Regeneration; Humans; Immunoenzyme Techniques; Kidney Diseases; Osteogenesis; Pulmonary Fibrosis; Transforming Growth Factor alpha; Transforming Growth Factor beta; Wound Healing

Although acetaminophen (APAP) is a commonly used analgesic antipyretic drug, hepatotoxicity and nephrotoxicity are common after the overdose. The main mechanism of APAP toxicity is oxidative stress based. Stress may induce the production of heme oxygenase 1 (HO)-1 which is regulated by interleukin (IL)-10 and inhibit the production of tumor necrosis factor-alpha (TNF-α). HO-1 expression is further regulated by nuclear factor erythroid 2-related factor 2 (Nrf2) and the transcription factor BTB and CNC homology 1 (BACH1). Drug-induced toxicity can be relieved by several natural products, which are preferred due to their dietary nature and less adverse reactions. Of these natural products, omega-3 (ω-3) fatty acids are known for anti-inflammatory and antioxidant actions. However, effects of ω-3fatty acids on APAP-induced hepatic and renal toxicity are not well addressed. We designed this study to test the potential protecting actions of ω-3 fatty acids (270 mg/kg Eicosapentaenoic acid and 180 mg/kg docosahexaenoic acid, orally, for 7 days) in hepatotoxicity and nephrotoxicity induced by APAP (2 g/kg, once orally on day 7) in rats. Moreover, we focused on the molecular mechanism underlying APAP hepatotoxicity and nephrotoxicity. Pre-treatment with ω-3 fatty acids enhanced liver and kidney functions indicated by decreased serum aminotransferases activities and serum creatinine and urea concentrations. These results were further confirmed by histopathological examination. Moreover, ω-3 fatty acids showed antioxidant properties confirmed by decreased malondialdehyde level and increased total antioxidant capacity. Antioxidant Nrf2, its regulators (HO-1 and BACH1) and the anti-inflammatory cytokine (IL-10) were up-regulated by APAP administration as a compensatory mechanism and they were normalized by ω-3 fatty acids. ω-3 fatty acids showed anti-inflammatory actions through down-regulating nuclear factor kappa B (NF-ĸB) and its downstream TNF-α. Moreover, Western blot analysis showed that ω-3 fatty acids promoted Nrf2 translocation to the nucleus; BACH1 exit from the nucleus and inhibited NF-ĸB nuclear translocation. These findings suggested the protecting actions of ω-3 fatty acids against APAP-induced hepatic and renal toxicity through regulation of antioxidant Nrf2 and inflammatory NF-ĸB pathways.

Topics: Acetaminophen; Animals; Anti-Inflammatory Agents; Basic-Leucine Zipper Transcription Factors; Cell Nucleus; Chemical and Drug Induced Liver Injury; Down-Regulation; Fatty Acids, Omega-3; Heme Oxygenase (Decyclizing); Kidney; Kidney Diseases; Liver; Male; NF-E2-Related Factor 2; NF-kappa B; Protective Agents; Rats, Sprague-Dawley; Repressor Proteins; Signal Transduction; Transforming Growth Factor alpha

In secondary hyperparathyroidism (SHPT), enhanced parathyroid levels of transforming growth factor-α (TGFα) increase EGF receptor (EGFR) activation causing parathyroid hyperplasia, high parathyroid hormone (PTH) and also reductions in vitamin D receptor (VDR) that limit vitamin D suppression of SHPT. Since anti-EGFR therapy is not an option in human SHPT, we evaluated ADAM17 as a therapeutic target to suppress parathyroid hyperplasia because ADAM17 is required to release mature TGFα, the most potent EGFR-activating ligand.. Computer analysis of the ADAM17 promoter identified TGFα and C/EBPβ as potential regulators of the ADAM17 gene. Their regulation of ADAM17 expression, TGFα/EGFR-driven growth and parathyroid gland (PTG) enlargement were assessed in promoter-reporter assays in A431 cells and corroborated in rat and human SHPT, using erlotinib as anti-EGFR therapy to suppress TGFα signals, active vitamin D to induce C/EBPβ or the combination.. While TGFα induced ADAM17-promoter activity by 2.2-fold exacerbating TGFα/EGFR-driven growth, ectopic C/EBPβ expression completely prevented this vicious synergy. Accordingly, in advanced human SHPT, parathyroid ADAM17 levels correlated directly with TGFα and inversely with C/EBPβ. Furthermore, combined erlotinib + calcitriol treatment suppressed TGFα/EGFR-cell growth and PTG enlargement more potently than erlotinib in part through calcitriol induction of C/EBPβ to inhibit ADAM17-promoter activity, mRNA and protein. Importantly, in rat SHPT, the correction of vitamin D deficiency effectively reversed the resistance to paricalcitol induction of C/EBPβ to suppress ADAM17 expression and PTG enlargement, reducing PTH by 50%.. In SHPT, correction of vitamin D and calcitriol deficiency induces parathyroid C/EBPβ to efficaciously attenuate the severe ADAM17/TGFα synergy, which drives PTG enlargement and high PTH.

Topics: ADAM Proteins; ADAM17 Protein; Animals; Antineoplastic Agents; Apoptosis; Blotting, Western; Calcitriol; CCAAT-Enhancer-Binding Protein-beta; Cell Proliferation; Cells, Cultured; ErbB Receptors; Erlotinib Hydrochloride; Gene Expression Regulation; Humans; Hyperparathyroidism, Secondary; Hyperplasia; Immunoenzyme Techniques; Kidney Diseases; Parathyroid Glands; Parathyroid Hormone; Rats; Real-Time Polymerase Chain Reaction; Receptors, Calcitriol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor alpha; Vitamin D; Vitamins

The mechanisms of progression of chronic kidney disease (CKD) are poorly understood. Epidemiologic studies suggest a strong genetic component, but the genes that contribute to the onset and progression of CKD are largely unknown. Here, we applied an experimental model of CKD (75% excision of total renal mass) to six different strains of mice and found that only the FVB/N strain developed renal lesions. We performed a genome-scan analysis in mice generated by back-crossing resistant and sensitive strains; we identified a major susceptibility locus (Ckdp1) on chromosome 6, which corresponds to regions on human chromosome 2 and 3 that link with CKD progression. In silico analysis revealed that the locus includes the gene encoding the EGF receptor (EGFR) ligand TGF-α. TGF-α protein levels markedly increased after nephron reduction exclusively in FVB/N mice, and this increase preceded the development of renal lesions. Furthermore, pharmacologic inhibition of EGFR prevented the development of renal lesions in the sensitive FVB/N strain. These data suggest that variable TGF-α expression may explain, in part, the genetic susceptibility to CKD progression. EGFR inhibition may be a therapeutic strategy to counteract the genetic predisposition to CKD.

Topics: Animals; Chromosome Mapping; Chronic Disease; Genetic Predisposition to Disease; Kidney Diseases; Kidney Failure, Chronic; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mutation; Nephrons; Transforming Growth Factor alpha

To investigate the antagonizing effect of Hirsutella sinensis (HS) on renal tubular epithelial-myofibroblast transdifferentiation (TEMT) and its possible pathogenic mechanism in rats with chronic aristolochic acid nephropathy (CAAN).. Eighteen male Sprague-Dawley rats were equally divided into 3 groups, the model (M) group, the intervention (I) group and the control (C) group. The 24 h urinary protein (UP) in rats was measured before intervention and at the end of the 1st, 4th, 8th, and 12th week, and creatinine clearance rate (CCr) was measured before intervention and at the end of the 12th week respectively. All rats were sacrificed at the end of the 12th week, their kidney was taken for examining the degree of fibrosis in renal interstitial with Masson's stain and determining mRNA and protein expressions of transforming growth factor-beta1 (TGF-beta1), Snail, alpha-smooth muscle actin (alpha-SMA) and cytokeratin in renal tissue by Real-time RT-PCR and immunohistochemistry staining, respectively.. Compared with the C group, CCr was significantly lower, while 24 h UP was higher; the relative area of interstitial fibrosis was significantly larger in the M group; besides, the mRNA and protein expressions of TGF-beta1, Snail and alpha-SMA were significantly up-regulated (P < 0.01 or P < 0.05), and those of cytokeratin were significantly down-regulated (P < 0.01) in renal tissue of the M group. While in the I group, all the above-mentioned abnormalities were restored to some extent (P < 0.05) and showed significant difference (all P < 0.05) as compared with those in the M group.. HS can downregulate TGF-beta1 and Snail expressions in renal tissue, antagonize TEMT and renal interstitial fibrosis, and improve renal function in CAAN rats.

Topics: Actins; Animals; Aristolochic Acids; Cell Transdifferentiation; Chronic Disease; Cordyceps; Drugs, Chinese Herbal; Fibroblasts; Kidney Diseases; Kidney Tubules; Male; Phytotherapy; Random Allocation; Rats; Rats, Sprague-Dawley; RNA, Messenger; Snail Family Transcription Factors; Transcription Factors; Transforming Growth Factor alpha

A disintegrin and metalloproteinase (ADAM)17 sheds growth factors from the cell membrane, including epidermal growth factor receptor (EGFR) ligand transforming growth factor (TGF)-alpha. In mice, angiotensin II infusion induces renal fibrosis via ADAM17-mediated TGF-alpha shedding and subsequent EGFR activation. Pharmacological ADAM17 inhibition reduced renal fibrotic lesions and improved renal function, positioning ADAM17 as a promising target of intervention in renal disease. We studied ADAM17 expression in the human kidney. ADAM17 mRNA was constitutively expressed in normal adult kidneys, with highest expression in distal tubules. In human renal disease, ADAM17 was de novo expressed in proximal tubules, peritubular capillaries, and glomerular mesangium and upregulated in podocytes. Glomerular mesangial and endothelial ADAM17 were associated with mesangial matrix expansion, focal glomerulosclerosis, and glomerular macrophage infiltration (P < 0.01). Peritubular capillary and proximal tubular ADAM17 were associated with interstitial fibrosis and interstitial macrophage infiltration (P < 0.05). Both glomerular and interstitial ADAM17 were associated with decreased renal function (P < 0.05). In renal fibrosis, ADAM17 colocalized with TGF-alpha. Moreover, in cultured human podocytes and proximal tubular cells, pharmacological ADAM17 inhibition reduced constitutive TGF-alpha shedding by 78% (P < 0.005) and 100% (P < 0.05), respectively, and phorbol ester-induced TGF-alpha shedding by 84% (P < 0.005) and 92% (P = 0.005), respectively. Finally, ADAM17 inhibition reduced cellular proliferation. In conclusion, the ADAM17 expression pattern and its role in shedding TGF-alpha from cultured human kidney cells suggest a role in the development of fibrosis. Since EGFR signaling is implicated in renal fibrosis, targeting ADAM17 to reduce availability of EGFR ligand TGF-alpha may represent a promising way of intervention in human renal disease.

Topics: ADAM Proteins; ADAM17 Protein; Adolescent; Adult; Aged; Aged, 80 and over; Capillaries; Cell Line; Cell Proliferation; Child; Child, Preschool; Creatinine; Dose-Response Relationship, Drug; Female; Fibrosis; Glomerular Filtration Rate; Humans; Hydroxamic Acids; Kidney; Kidney Diseases; Kidney Tubules, Proximal; Male; Middle Aged; Podocytes; Protease Inhibitors; RNA, Messenger; Transforming Growth Factor alpha; Up-Regulation

Liver-type fatty-acid-binding protein (L-FABP), which has high affinity for long-chain fatty acid oxidation products, may be an effective endogenous antioxidant. To examine the role of L-FABP in tubulointerstitial damage, we used a unilateral ureteral obstruction (UUO) model. We established human L-FABP (hL-FABP) gene transgenic (Tg) mice and compared the tubulointerstitial pathology of the Tg mice (n = 23) with that of the wild-type (WT) mice (n = 23). Mice were sacrificed on days 2, 4, 5, or 7 after UUO. Although mouse L-FABP was not expressed in WT mice, hL-FABP was expressed in the proximal tubules of the Tg mice with UUO (UUO-Tg) and in sham-operated Tg mice. The expression of renal hL-FABP was significantly increased in UUO-Tg compared with sham-operated Tg mice. The number of macrophages (F4/80) infiltrating the interstitium and the level of expression of MCP-1 and MCP-3 were significantly lower in UUO-Tg kidneys compared with UUO-WT kidneys. In UUO-Tg kidneys, the degree of the tubulointerstitial injury and the deposition of type I collagen were significantly lower than that of UUO-WT kidneys. On day 7, lipid peroxidation product accumulated in the UUO-WT kidneys but not in that of UUO-Tg kidneys. In conclusion, renal L-FABP may reduce the oxidative stress in the UUO model, ameliorating tubulointerstitial damage.

Topics: Animals; Carboxypeptidases A; Chemokine CCL2; Collagen Type I; Fatty Acid-Binding Proteins; Kidney Diseases; Kidney Tubules; Lipids; Mice; Mice, Transgenic; Oxidative Stress; Transforming Growth Factor alpha; Ureteral Obstruction

The parathyroid hyperplasia secondary to kidney disease is associated with enhanced expression of the growth promoter transforming growth factor-alpha (TGF-alpha). TGF-alpha stimulates growth through activation of its receptor, the epidermal growth factor receptor (EGFR), normally expressed in the parathyroid glands. Because enhanced coexpression of TGF-alpha and EGFR causes aggressive cellular growth, these studies utilized highly specific inhibitors of EGFR tyrosine kinase, a step mandatory for TGF-alpha-induced EGFR activation, to assess the contribution of growth signals from enhanced expression of TGF-alpha exclusively or both TGF-alpha and EGFR to the rapid parathyroid growth induced by kidney disease and exacerbated by high-phosphorus (P) and low-calcium (Ca) diets in rats. The enhancement in parathyroid gland weight and proliferating activity (proliferating cell nuclear antigen/Ki67) induced by kidney disease and aggravated by either high P or low Ca intake, within the first week after 5/6 nephrectomy, in rats, coincided with simultaneous increases (2- to 3-fold) in TGF-alpha and EGFR content. Conversely, prevention of the increases in both TGF-alpha and EGFR paralleled the efficacy of either P restriction or high-Ca intake in ameliorating uremia-induced parathyroid hyperplasia. More importantly, suppression of TGF-alpha/EGFR signaling, through prophylactic administration of potent and highly selective inhibitors of ligand-induced EGFR activation, completely prevented both high-P- and low-Ca-induced parathyroid hyperplasia as well as TGF-alpha self-upregulation. Thus enhanced parathyroid TGF-alpha/EGFR expression, self-upregulation, and growth signals occur early in kidney disease, are aggravated by low-Ca and high-P intake, and constitute the main pathogenic mechanism of the severity of parathyroid hyperplasia.

Topics: Animals; Calcium, Dietary; ErbB Receptors; Female; Hyperplasia; Kidney Diseases; Parathyroid Glands; Phosphorus, Dietary; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Transforming Growth Factor alpha; Up-Regulation

The AP-1 transcription factor, composed of Jun and Fos proteins, plays a crucial role in the fine tuning of cell proliferation. We showed previously that AP-1 complexes are activated during the proliferative response that parallels the development of renal lesions after nephron reduction, but little is known about the specific role of individual Jun/Fos components in the deterioration process. Here we used JunD knockout (JunD-/-) mice and an experimental model of chronic renal injury (75% nephron reduction) to explore the role of JunD. Nephron reduction resulted in an initial compensatory growth phase that did not require JunD. JunD, however, was essential to inhibit a second wave of cell proliferation and to halt the development of severe glomerular sclerosis, tubular dilation, and interstitial fibrosis. We show that the effects of junD inactivation are not cell autonomous and involve upregulation of the paracrine mitogen, TGF-alpha. Expression of a transgene (REM) encoding a dominant negative isoform of the EGFR, the receptor for TGF-alpha, prevented the second wave of cell proliferation and the development of renal lesions in bitransgenic JunD-/-/REM mice. We propose that JunD is part of a regulatory network that controls proliferation to prevent pathological progression in chronic renal diseases.

Topics: Animals; Cell Division; Chronic Disease; Epidermal Growth Factor; ErbB Receptors; Humans; Kidney; Kidney Diseases; Mice; Mice, Knockout; Mitogens; Paracrine Communication; Proto-Oncogene Proteins c-jun; Signal Transduction; Transcription Factor AP-1; Transforming Growth Factor alpha; Up-Regulation

We studied control of the epidermal growth factor (EGF) receptor and its ligands during kidney injury, since they may be importantly involved in repair.. The folic acid model of renal injury was used in these studies. Messenger RNA (mRNA) was evaluated by solution hybridization. Immunohistochemistry of transforming growth factor alpha (TGF-alpha) was also performed.. Twenty-four hours after folic acid induced acute renal injury, creatinine increased from 0.3 +/- 0.03 mg/dl in controls to 2.0 +/- 0.8 mg/dl in folic acid injured kidneys (n = 4, p < 0.03). mRNA for the EGF receptor was increased nearly sevenfold by 24 h, and mRNA for the receptor was increased as early as 1 h following folic acid treatment. EGF receptor ligand caused a profound downregulation of the receptors in proximal tubule basolateral membranes, but receptors returned rapidly to the membrane surface in injured kidneys. The mRNA levels for heparin-binding EGF and TGF-alpha, two EGF receptor ligands, increased within 1 h of injury. TGF-alpha mRNA increased from 1.0 +/- 0.09 (relative densitometry units) in control animals to 2.9 +/- 0.13 in folic acid treated rats at 24 h (n = 4, p < 0.01), and immunohistochemical staining for TGF-alpha increased in injured kidneys at distal nephron sites.. These studies indicate that upregulation of the EGF receptor is related to an increase in mRNA. The rapid return of receptors to the membrane surface following ligand stimulation may be useful in maintaining a mitogenic stimulus. Multiple EGF-like ligands may be important in activating the upregulated EGF receptor during repair from renal injury.

Topics: Acute Disease; Animals; Creatinine; Epidermal Growth Factor; ErbB Receptors; Folic Acid; Gene Expression; Heparin-binding EGF-like Growth Factor; Intercellular Signaling Peptides and Proteins; Ischemia; Kidney Diseases; Ligands; Male; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor alpha

Topics: Chromosomes, Human, Pair 2; Diabetes Mellitus, Type 2; DNA Primers; Gene Library; Hearing Loss, Sensorineural; Humans; Kidney Diseases; Obesity; Retinitis Pigmentosa; Syndrome; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF-alpha) is a member of the epidermal growth factor (EGF) family of proteins and, like EGF, elicits its cellular function by binding to the EGF receptor. EGF stimulation may have a role in several normal and pathologic processes in the kidney, and EGF has been implicated in the development of renal cysts in vitro and in human autosomal dominant polycystic kidney disease. We sought to determine whether renal expression of an EGF-like protein (TGF-alpha) could lead to the formation of renal cysts in vivo. We examined morphologic alterations to the normal kidney caused by renal expression of a TGF-alpha transgene linked to a mouse metallothionein promoter stably integrated into the genome of the CD1 mouse. TGF-alpha transgene expression was induced with exogenous zinc treatment starting at 4 weeks of age, and mice were killed at 8 weeks of age. The transgene was expressed at higher levels in female transgenic mice than in male transgenic mice. The augmented expression of the TGF-alpha transgene in females was associated with increased renal size and the development of renal epithelial cysts. Both male and female mice exhibited increases in glomerular size and mesangial volume density. These results provide evidence that stimulation by an endogenous EGF-like protein can lead to renal enlargement, glomerular mesangial expansion, and renal cyst formation.

Topics: Animals; Base Sequence; Cell Division; Cysts; Disease Models, Animal; DNA; Female; Gene Expression Regulation; Glomerular Mesangium; Kidney; Kidney Diseases; Male; Mice; Mice, Transgenic; Molecular Sequence Data; Transforming Growth Factor alpha