Ca2+/Calmodulin induces translocation of membrane-associated TSC2 to the nucleus where it suppresses CYP24A1 expression

Tuberous sclerosis complex 2 (TSC2) is a tumor-suppressor protein. A loss of TSC2 function induces hyperactivation of mechanistic target of rapamycin (mTOR). The C-terminal region of TSC2 contains a calmodulin (CaM) binding region and the CaM-TSC2 interaction contributes to proper mTOR activity. However, other downstream signaling pathways/effectors activated by the CaM-TSC2 complex have not been fully elucidated. In this study, we found that activation of Ca2+/CaM signaling resulted in the translocation of membrane-associated TSC2 to the nucleus and suppressed the transcriptional activity of the vitamin D receptor (VDR). TSC2 was released from the membrane in an activated CaM-dependent state in rat brain and HeLa cells. It subsequently formed a transcriptional complex to partially suppress the transcription of CYP24A1, a well-known VDR target gene. These data suggest, in part, that TSC2 attenuates VDR-associated transcriptional regulation via Ca2+/CaM signaling.

Brown Rice Inhibits Development of Nonalcoholic Fatty Liver Disease in Obese Zucker (fa/fa) Rats by Increasing Lipid Oxidation Via Activation of Retinoic Acid Synthesis

BACKGROUND

White rice and its unrefined form, brown rice, contain numerous compounds that are beneficial to human health. However, the starch content of rice can contribute to obesity, a main risk factor for nonalcoholic fatty liver disease (NAFLD).

OBJECTIVES

We investigated the effect of rice consumption on NAFLD and its underlying molecular mechanism.

METHODS

We randomly divided 7-week-old male obese Zucker (fa/fa) rats, an animal model of NAFLD, into 3 groups (n = 10 each) fed 1 of 3 diets for 10 weeks: a control diet (Cont; AIN-93G diet; 53% cornstarch), a white rice diet (WR; AIN-93G diet with cornstarch replaced with white rice powder), or a brown rice diet (BR; AIN-93G diet with cornstarch replaced with brown rice powder). Liver fat accumulation and gene expression related to lipid and vitamin A metabolisms, including retinoic acid (RA) signaling, were analyzed.

RESULTS

Hepatic lipid values were significantly decreased in the BR group compared with the Cont group, by 0.4-fold (P < 0.05). The expression of genes related to hepatic fatty acid oxidation, such as carnitine palmitoyltransferase 2, was approximately 2.1-fold higher in the BR group than the Cont group (P < 0.05). The expression of peroxisomal acyl-coenzyme A oxidase 1 and acyl-CoA dehydrogenase medium chain was also significantly increased, by 1.6-fold, in the BR group compared with the Cont group (P < 0.05). The expression of VLDL-secretion-related genes, such as microsomal triglyceride transfer protein, was also significantly higher in the BR group (2.4-fold; P < 0.05). Furthermore, aldehyde dehydrogenase 1 family member A1, an RA synthase gene, was 2-fold higher in the BR group than the Cont group (P < 0.05).

CONCLUSIONS

Brown rice prevented development of NAFLD in obese Zucker (fa/fa) rats. The beneficial effects of pregelatinized rice on NAFLD could be manifested as increased fatty acid oxidation and VLDL secretion, which are regulated by RA signaling.

Niclosamide activates the AMP-activated protein kinase complex containing the β2 subunit independently of AMP

AMP-activated protein kinase (AMPK) regulates cellular energy homeostasis by suppressing anabolic processes and activating catabolic processes. AMPK activators are an important therapeutic target for metabolic syndrome due to favorable physiological effects of AMPK activation on metabolism. Recent studies show that niclosamide, an FDA-approved anthelmintic drug that exerts an uncoupling effect on the mitochondria of the parasite, improves blood glucose levels and reduces hepatic steatosis in mice via AMPK activation. Niclosamide is thought to activate AMPK by increasing AMP/ATP ratio through mitochondrial uncoupling, but details of its action remain unclear. In this study, we found that niclosamide also activates the AMPK complex, which contains the AMP-insensitive γ subunit. Further, niclosamide shows greater AMPK activation for the AMPK complex containing β2 subunit, but not the β1 subunit. This effect was inhibited by substituting the Ser108 residue of the β2 subunit to alanine. Niclosamide displays a novel AMPK activation mechanism independent of the increase in AMP/ATP ratio.

Activation of peroxisome proliferator-activated receptor gamma/small heterodimer partner pathway prevents high fat diet-induced obesity and hepatic steatosis in Sprague-Dawley rats fed soybean meal

Soybeans are a complete nutritional resource and soybean proteins are known to affect lipid metabolism via multiple mechanisms. Soybean meal (SBM) is produced after extraction of soybean oil and in this study, we investigated the ability whether the SBM could prevent high fat diet-induced obesity and understand the underlying mechanisms. Male Sprague-Dawley rats, aged 5 weeks, were randomly divided into three groups (n=8 each) and fed one of three diets for 28 days: Cont (AIN-93G), HFD (high fat diet with 40% of calories derived from fat) and HFD+SBM (HFD with 30% SBM). White adipose tissue weight as well as plasma and hepatic triglycerides were significantly decreased in HFD+SBM rats. Expression of hepatic SREBP-1 and its target genes was significantly decreased in HFD+SBM rats. Meanwhile, expression of SHP gene expression was significantly increased in HFD+SBM, and there was a negative correlation between SHP and SREBP-1 expression. Together these results suggest that hepatic SREBP-1 gene expression is negatively regulated by SHP. Expression of PPARG, the transcriptional factor that regulates SHP expression, was increased in HFD+SBM rats. Furthermore, expression of genes controlled by PPARG/SHP, such as those involved in hepatic gluconeogenesis, was also significantly decreased in HFD+SBM rats. Therefore, in addition to the previous findings of SBM on obesity here we show an additional mechanism which by changing the expression of genes involved in lipid metabolism via the PPARG/SHP pathway in the liver.

Metabolic abnormalities induced by mitochondrial dysfunction in skeletal muscle of the renal carcinoma Eker (TSC2+/-) rat model

Tuberous sclerosis complex 2 (TSC2) is a mediator of insulin signal transduction, and a loss of function in TSC2 induces hyperactivation of mTORC1 pathway, which leads to tumorigenesis. We have previously demonstrated that Eker rat model, which is heterozygous for a TSC2 mutation, exhibits hyperglycemia and hyperketonemia. The present study was to investigate whether these changes also can affect metabolism in skeletal muscle of the Eker rat. Wild-type (TSC2+/+) and Eker (TSC2+/-) rats underwent an oral glucose tolerance test, and the latter showed decrease in whole-body glucose utilization. Additionally, reductions in the expression of glycolysis-, lipolysis-, and ketone body-related genes in skeletal muscle were observed in Eker rats. Furthermore, ATP content and mitochondrial DNA copy number were lower in skeletal muscle of Eker rats. These data demonstrate that heterozygous to mutation TSC2 not only affects the liver metabolism, but also skeletal muscle metabolism, via mitochondrial dysfunction.

The tuberous sclerosis complex model Eker (TSC2+/-) rat exhibits hyperglycemia and hyperketonemia due to decreased glycolysis in the liver

Tuberous sclerosis complex (TSC) presents as benign tumors that affect the brain, kidneys, lungs and skin. The inactivation of TSC2 gene, through loss of heterozygosity is responsible for tumor development in TSC. Since TSC patients are carriers of heterozygous a TSC2; mutation, to reveal the risk factors which these patients carry prior to tumor development is important. In this experiment, Eker rat which carry a mutation in this TSC2 gene were analyzed for their metabolic changes. Wild-type (TSC2+/+) and heterozygous mutant TSC2 (TSC2+/-) Eker rats were raised for 100 days. As a result, the Eker rats were found to exhibit hyperglycemia and hyperketonemia. However the high ketone body production in the liver was observed without accompanying increased levels of plasma free fatty acids or insulin. Further, production of the ketone body β-hydroxybutyrate was inhibited due to the low NADH/NAD(+) ratio resulting from the restraint on glycolysis, which was followed by inhibition of the malate-aspartate shuttle and TCA cycle. Therefore, we conclude that glycolysis is restrained in the livers of TSC2 heterozygous mutant rats, and these defects lead to abnormal production of acetoacetate.

Activation of Nrf2/Keap1 signaling and autophagy induction against oxidative stress in heart in iron deficiency

We investigated the effects of dietary iron deficiency on the redox system in the heart. Dietary iron deficiency increased heart weight and accumulation of carbonylated proteins. However, expression levels of heme oxygenase-1 and LC3-II, an antioxidant enzyme and an autophagic marker, respectively, in iron-deficient mice were upregulated compared to the control group, resulting in a surrogate phenomenon against oxidative stress.

[Epithelioid angiomyolipoma : a case report]

A 63-year-old woman with a right renal tumor diagnosed by ultrasound, consulted our hospital in October 2008. The findings of her physical examination were unremarkable. The results of urinalysis and other routine blood tests were normal. The urinary cytology was negative for malignant cells. Dynamic computed tomography showed a right renal mass (diameter, 7.5 cm), which was enhanced in the early phase and washed out in the late phase. We initially thought that the patient had renal cell carcinoma. Therefore, laparoscopic right nephrectomy was performed in October 2008. The tumor section was found to be encapsulated, and focal hemorrhage and necrosis were observed. Histological examination of the tumor by hematoxylin-eosin staining revealed that it contained polygonal cells, eosinophilic cytoplasm and large nuclei. Immunohistochemical staining of anticytokeratin antibodies AE1/AE3 and CAM5.2 (markers for renal cell carcinoma) was negative. However, immunohistochemical staining of HMB-45, a marker for melanoma, was positive. The patient was finally diagnosed with epithelioid angiomyolipoma. She did not show any evidence of tumor recurrence for 25 months after the surgery.

Interaction of activated Rab5 with actin-bundling proteins, L- and T-plastin and its relevance to endocytic functions in mammalian cells

Rab5 is a GTP-binding protein that is crucial for endocytic machinery functions. We previously identified L-plastin as a binding protein for Rab5, using an affinity column with constitutively active Rab5. L- and T-plastin are isoforms of a plastin protein family belonging to actin-bundling proteins that are implicated in the regulation of cell morphology, lamellipodium protrusion, bacterial invasion and tumor progression. However, the physiological relevance of Rab5 binding to plastin has remained unclear. Here, we show that L- and T-plastin interacted only with activated Rab5 and that they co-localized with Rab5 on the plasma membrane and endosome. Rab5 activity was also higher in both L- and T-plastin over-expressing Cos-1 cells. Furthermore, expression of L- and T-plastin increased the rate of fluid-phase endocytosis. These findings imply that the Rab5 is either activated or the activity is sustained by interaction with plastin, and that this interaction influences endocytic activity.

Iron deficiency down-regulates the Akt/TSC1-TSC2/mammalian Target of Rapamycin signaling pathway in rats and in COS-1 cells

Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity.

[Primary signet-ring cell carcinoma of the urinary bladder: a case report]

We report a case of signet-ring cell carcinoma of the urinary bladder. A 60-year-old man was hospitalized because of total macrohematuria. Cystoscopic examination revealed a non-papillary sessile tumor on the posterior wall of the urinary bladder. The pathological diagnosis was stage pT1 signet ring cell carcinoma. Upper gastrointestinal endoscopy and computed tomographic scanning revealed no involvement of other organs. Radical cystectomy and creation of an ileal neobladder were performed. The histopathological stage was pT3aN0M0. Adjuvant chemotherapy (TS-1) was performed and the patient is currently free from disease at eight months after the surgery. This disease is usually diagnosed at an advanced stage and has a poor prognosis. To our knowledge, this is the first case report on the creation of an ileal neobladder for the treatment of primary signet-ring cell carcinoma of the urinary bladder.

Rab5 affinity chromatography without nonhydrolyzable GTP analogues

Rab5 is an important small GTPase involved in endocytosis and membrane trafficking. Rab5-binding proteins can be identified using Rab5 affinity chromatography with nonhydrolyzable GTP analogues such as GTPgammaS or GppNHp. However, this method requires significant quantities of the GTP analogue and is thus time-consuming and expensive. In the present report we show a faster and more cost-effective method that does not use a GTP analogue but uses constitutively the active Rab5 mutant (Rab5Q79L) as a ligand. To validate this method, the binding of EEA-1 was confirmed and several novel Rab5-binding proteins were also identified by 2-dimensional electrophoresis and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS).

Application of SYPRO Ruby- and Flamingo-stained polyacrylamide gels to Western blot analysis

Western blot analysis has been a useful method for analysis of expression levels of specific proteins and is conducted after sodium dodecyl sulfate (SDS) or native polyacrylamide gel electrophoresis without staining the gel. However, when it is necessary to analyze the gel, duplicate polyacrylamide gels usually must be prepared, one of which is stained, leading to the consumption of precious sample. Thus, we developed a convenient and efficient Western blotting method using a stained gel. This simple modification should be beneficial for analyzing samples that are limited in quantity and/or samples for which the stained gel serves as the loading control.

Change of epigenetic control of cystathionine beta-synthase gene expression through dietary vitamin B12 is not recovered by methionine supplementation

BACKGROUND/AIMS

Vitamin B12 (B-12) is an essential cofactor for methionine synthase, and methionine is critical for the methylation of various biological molecules including DNA. Whether changes in B-12 levels can alter specific gene expression through DNA methylation and whether dietary methionine has any effect on general DNA methylation status still remains controversial.

METHODS

We raised severely B-12-deficient rats as well severely-B-12 deficient rats but supplemented with 5% methionine. mRNA levels of methionine cycle-related enzymes were analyzed.

RESULTS

Gene expression patterns changed under B-12-deficient conditions but were recovered by dietary methionine supplementation to B-12-deficient rats. However, cystathionine beta-synthase mRNA levels, which had decreased under B-12-deficient conditions, did not recover with supplementary dietary methionine. The CpG island of the cystathionine beta-synthase promoter was hypomethylated in B-12-deficient rats, and showed no recovery after methionine addition.

CONCLUSIONS

Dietary B-12 can affect epigenetic machinery by regulating DNA methylation status and dietary methionine may have small effects on DNA methylation.

Tuberous sclerosis complex 2 loss-of-function mutation regulates reactive oxygen species production through Rac1 activation

The products of the TSC1 (hamartin) and TCS2 (tuberin) tumor suppressor genes negatively regulate cell growth by inhibiting mTOR signaling. Recent research has led to the postulation that tuberin and/or hamartin are involved in tumor migration, presumably through Rho activation. Here we show that LEF-8 cells, which contain a Y1571 missense mutation in tuberin, express higher Rac1 activity than tuberin negative and positive cells. We also provide evidence of obvious lamellipodia formation in LEF-8 cells. Since the production of TSC2(Y1571H) cannot form a hetero-complex with hamartin, we further analyzed another mutant, TSC2(R611Q), which also lacks the ability to form a complex with hamartin. Introducing both forms of mutated TSC2 into COS-1 cells increased Rac1 activity as well as cell motility. We also found these two mutants interacted with Rac1. We further demonstrated that the introduction of mutated TSC2 into COS-1 cells can generate higher reactive oxygen species (ROS). These results indicate that loss-of-function mutated tuberin can activate Rac1 and thereby increase ROS production.

CCR2 signaling contributes to ischemia-reperfusion injury in kidney

Examined were CCR2-deficient mice to clarify the contribution of macrophages via monocyte chemoattractant protein 1 (MCP-1 or CCL2)/CCR2 signaling to the pathogenesis of renal ischemia-reperfusion injury. Also evaluated was the therapeutic effects via the inhibition of MCP-1/CCR2 signaling with propagermanium (3-oxygermylpropionic acid polymer) and RS-504393. Renal artery and vein of the left kidney were occluded with a vascular clamp for 60 min. A large number of infiltrated cells and marked acute tubular necrosis in outer medulla after renal ischemia-reperfusion injury was observed. Ischemia-reperfusion induced the expression of MCP-1 mRNA and protein in injured kidneys, followed by CCR2-positive macrophages in interstitium in wild-type mice. The expression of MCP-1 was decreased in CCR2-deficient mice compared with wild-type mice. The number of interstitial infiltrated macrophages was markedly smaller in the CCR2-deficient mice after ischemia-reperfusion. CCR2-deficient mice decreased the number of interstitial inducible nitric oxide synthase-positive cells after ischemia-reperfusion. The area of tubular necrosis in CCR2-deficient mice was significantly lower than that of wild-type mice after ischemia-reperfusion. In addition, CCR2-deficient mice diminished KC, macrophage inflammatory protein 2, epithelial cell-derived neutrophil-activating peptide 78, and neutrophil-activating peptide 2 expression compared with wild-type mice accompanied with the reduction of interstitial granulocyte infiltration. Similarly, propagermanium and RS-504393 reduced the number of interstitial infiltrated cells and tubular necrosis up to 96 h after ischemia-reperfusion injury. These results revealed that MCP-1 via CCR2 signaling plays a key role in the pathogenesis of renal ischemia-reperfusion injury through infiltration and activation of macrophages, and it offers a therapeutic target for ischemia-reperfusion.

Gene therapy expressing amino-terminal truncated monocyte chemoattractant protein-1 prevents renal ischemia-reperfusion injury

Ischemia-reperfusion is closely associated with tissue damage in various organs, including kidney. Despite clinical investigations, useful therapy for renal ischemia-reperfusion injury is not available so far. This study evaluated therapeutic effects of gene therapy expressing an amino-terminal deletion mutant of MCP-1 called 7ND to inhibit monocyte chemoattractant protein (MCP)-1/CCR2 signaling in vivo on renal ischemia-reperfusion injury. 7ND gene was transferred into the femoral muscle of Balb/c mice. Renal artery and vein of the left kidney were occluded with a vascular clamp for 60 min. A large number of infiltrated cells were observed, as was marked acute tubular necrosis in outer medulla after renal ischemia-reperfusion injury in control mice, while these lesions were significantly decreased in 7ND gene-transfected mice. Macrophages in the interstitial region, most of which were CCR2-positive, were markedly decreased in 7ND gene-transfected mice after reperfusion. Although macrophages infiltrated around MCP-1-positive cells in control mice, the smaller number of F4/80-positive cells could infiltrate into the neighbor of MCP-1-positive cells in 7ND-treated mice. These results provide evidence that gene therapy by 7ND is potentially a powerful therapeutic approach to inhibit MCP-1/CCR2 signaling, resulting in rescue from renal ischemia-reperfusion injury.

PPARgamma gene polymorphism is associated with exercise-mediated changes of insulin resistance in healthy men

Exercise training improves insulin sensitivity, but individual responses vary greatly. Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a regulator of adipose cell differentiation and plays an important role in systemic insulin action. We investigated whether PPARgamma gene polymorphism affects insulin resistance in response to exercise in Japanese healthy men. The exercise program at an individual intensity of 50% of the maximal heart rate was performed for 20 to 60 min/d, and 2 to 3 days per week to attain a level of physical activity of 700 kcal/wk. The program was conducted for 3 months without any dietary intervention, and the clinical and metabolic characteristics were examined before and after the exercise program. Body mass index (BMI) did not change significantly after the exercise program, whereas percentage of body fat (% body fat), fasting plasma glucose (FPG), and serum leptin levels decreased significantly. Pro12Ala polymorphism in PPARgamma gene was performed on genomic DNA isolated from human leukocytes and examined with polymerase chain reaction (PCR) and subsequent restriction enzyme analysis using BstU-I. In this study, the Ala allele did not correlate with fasting immunoreactive insulin (IRI) and homeostasis model assessment-insulin resistance index (HOMA-R) at baseline, but did so with the changes in IRI and HOMA-R after exercise (DeltaIRI, Pro/Pro 0.55 +/- 3.49 microU/mL v Pro/Ala -2.83 +/- 1.47 microU/mL, P <.05; DeltaHOMA-R, Pro/Pro 0.09 +/- 0.86 v Pro/Ala -0.61 +/- 0.32, P <.05). This result suggests that the Ala allele is associated with improvement in insulin resistance after exercise. We conclude that PPARgamma gene polymorphism may be a reliable indicator of whether exercise will have a beneficial effect as part of the treatment of insulin resistance syndrome.

Lowered blood concentration of tacrolimus and its recovery with changes in expression of CYP3A and P-glycoprotein after high-dose steroid therapy

BACKGROUND

In a living-donor liver transplant patient continuously receiving tacrolimus (FK506), pulse steroid therapy for 3 days caused the blood concentration of FK506 to decrease, followed by a gradual recovery to presteroid levels within 2 weeks. We conducted a study in rats to clarify the mechanism of the changes in the blood concentration of FK506 during and after steroid therapy.

METHODS

Rats were intraperitoneally treated with a low dose (1 mg/kg per day) or a high dose (75 mg/kg per day) of dexamethasone (DEX) for 4 days and, at 1.5 hours after the last dose, were given FK506 (2 mg/kg) intravenously (IV) or orally (PO). Blood concentrations of FK506 and changes in the expression levels of P-glycoprotein and CYP3A2 in the liver and intestine were monitored.

RESULTS

In the low-dose DEX group, the blood concentrations of FK506 after PO administration of FK506 were significantly lowered compared with those in the untreated group, while there was no such difference after IV administration. In the high-dose DEX group, the blood concentrations of FK506 after either IV or PO administration were significantly lowered. Consequently, the bioavailability of FK506 was decreased by DEX treatment, and the total clearance was significantly increased by high-dose DEX treatment. The pharmacokinetic parameters gradually recovered within 2 weeks after high-dose DEX treatment. In the high-dose DEX group, the protein levels of P-glycoprotein and CYP3A2 in the liver and intestine increased just after the treatment then decreased to normal levels within 2 weeks.

CONCLUSION

Our results indicate that the decrease in the blood FK506 concentration caused by high-dose steroid therapy is a consequence of the induction of P-glycoprotein and CYP3A in the liver and intestine, and these changes were reversed within 2 weeks after cessation of steroid therapy.

Role of Cytokines and Chemokines in Renal Ischemia-Reperfusion Injury

Cytokines and chemokines produced by renal tubular epithelial cells and infiltrated cells are critical factors in inflammatory processes of renal ischemia-reperfusion injury. In vitro studies reveal that renal tubular epithelial cells have the potential to produce diverse cytokines, chemokines and other mediators, such as tumor necrosis factor-alpha, interleukin-1 (IL-1), monocyte chemoattractant protein-1, IL-8, platelet-derived growth factor, regulated upon activation, normal T cell expressed and secreted, endothelin-1 and vascular endothelial growth factor (VEGF). Huge numbers of in vivo studies show that cytokines, chemokines and adhesion molecules in diseased kidney together govern critical aspects of ischemia-reperfusion injury. Leukocyte­endothelial cell interactions are critical processes of leukocytic infiltration, which are pathologically key factors in inflammatory processes of renal ischemia-reperfusion injury. Leukocyte­endothelial interactions are regulated by a cascade of molecular steps of cytokines, chemokines and adhesion molecules. In contrast, the intracellular cascades of cytokine and chemokine expression in the renal ischemia-reperfusion injury remain to be investigated. p38 mitogen-activated protein kinase is one of the essential mediators in cytokine and chemokine expression through the activation of nuclear factor-kappaB and activating protein-1. Moreover, hypoxia-inducible factor-1 (HIF-1) is a transcription factor activated by reductions in oxygen concentration. HIF-1­related gene expression, such as erythropoietin or VEGF, results in protection of ischemia reperfusion injury. This review focuses on the contribution of cytokines, chemokines and their related molecules to the inflammatory cascade in renal ischemia-reperfusion injury. (c) 2002 Prous Science. All rights reserved.

The beneficial effects of lymphocytapheresis for treatment of nephrotic syndrome

A considerable permeability factor (or factors) derived from circulating T cells has a crucial role in proteinuria of nephrotic syndrome (NS). We attempted to remove pathogenic T cells through lymphocytapheresis (LCAP) in 6 patients with primary NS, 2 patients with minimal change nephrotic syndrome (MCNS), 2 patients with focal segmental glomerulosclerosis (FSGS), 1 patient with membranous nephropathy (MN), and 1 patient with MN and FSGS using Cellsorba (Asahi Medical Co., Osaka, Japan). LCAP was performed 2 times in 2 consecutive weeks and was followed with corticosteroid therapy with or without cyclosporine A in 5 patients. Two patients with MCNS, 1 with FSGS, and 1 with MN and FSGS showed a dramatic decrease of proteinuria (-30% and -94%) in their urine protein/creatinine ratio. Three out of 4 patients had a complete or partial remission (proteinuria <1g/day) within 8 weeks following immunosuppressive therapy. During the LCAP, T cells, especially activated T cells, decreased significantly in the response group. The other 2 patients, 1 with FSGS and 1 with MN, however, had no response to LCAP and following immunosuppressive therapy or low-density lipoprotein apheresis and suffered from end-stage renal failure or death by pneumonia. These results suggested that LCAP might have a beneficial effect on the treatment of NS, especially MCNS and in some patients with FSGS, despite varying responses to LCAP and concomitant immunosuppressive therapy.

Diurnal variation of hemodynamic indices in non-dipper hypertensive patients

The purpose of this study was to elucidate the underlying mechanisms of blunted nocturnal blood pressure reduction in non-dipper hypertensive patients. We studied the diurnal variations in systemic hemodynamic indices and baroreflex sensitivity. In 45 subjects with essential hypertension (24 men; mean age, 49+/-1 years), intra-arterial pressure was monitored telemetrically. Non-dippers were defined as those with a nocturnal reduction of systolic blood pressure of less than 10% of daytime systolic blood pressure. Stroke volume was determined using Wesseling's pulse contour method, calibrated with indocyanine green dilution. Baroreflex sensitivity was calculated as deltapulse interval/deltasystolic blood pressure on spontaneous variations. The mean values of the hemodynamic parameters were calculated every 30 min. Twenty-six subjects were classified as non-dippers. Daytime blood pressure was not significantly different between dippers (149+/-4/87+/-3 mmHg) and non-dippers (147+/-3/82+/-2 mmHg), while the nighttime blood pressure was significantly reduced in dippers (131+/-3/77+/-2 mmHg) but not in non-dippers (145+/-3/80+/-2 mmHg). Nocturnal decreases in both cardiac index and stroke index were smaller in non-dippers (-12.0+/-1.2% and 1.5+/-1.0%) than in dippers (-17.5+/-1.4% and -2.2+/-1.1%). Baroreflex sensitivity significantly increased at nighttime both in dippers (6.5+/-0.6 to 8.0+/-0.7 ms/mmHg) and in non-dippers (5.1+/-0.3 to 6.4+/-0.4 ms/mmHg). Neither daytime nor nighttime baroreflex sensitivity was significantly different between the groups. We conclude that the hemodynamics of non-dipper essential hypertension are characterized by an inadequate nocturnal decrease in cardiac index and stroke index, suggestive of relative volume expansion or malsuppressed sympathetic activity.

Up-regulation of monocyte chemoattractant protein-1 in tubulointerstitial lesions of human diabetic nephropathy

BACKGROUND

We previously described that monocyte chemoattractant protein-1 (MCP-1) plays an important role in progressive glomerular and interstitial damage in inflammatory renal diseases. However, the expression of MCP-1 in diabetic nephropathy remains to be investigated.

METHODS

We examined whether locally expressed MCP-1 participates in human diabetic nephropathy via recruiting and activating monocytes/macrophages (Mphi). Urinary and serum MCP-1 levels were measured by enzyme-linked immunosorbent assay in 45 patients with diabetic nephropathy. The presence of MCP-1 in diseased kidneys was determined by immunohistochemical and in situ hybridization analyses.

RESULTS

Urinary MCP-1 levels were significantly elevated in patients with diabetic nephrotic syndrome and advanced tubulointerstitial lesions. Moreover, urinary levels of MCP-1 were well correlated with the number of CD68-positive infiltrating cells in the interstitium. In contrast, serum MCP-1 levels remained similar to those of healthy volunteers. Furthermore, we detected the MCP-1-positive cells in the interstitium of diabetic nephropathy via both immunohistochemical and in situ hybridization analyses.

CONCLUSION

These observations suggest that locally produced MCP-1 may be involved in the development of advanced diabetic nephropathy, especially in the formation of tubulointerstitial lesions possibly through Mphi recruitment and activation. Moreover, up-regulation of MCP-1 may be a common pathway involved in the progressive tubulointerstitial damage in diabetic nephropathy as well as inflammatory renal diseases.

A new anti-inflammatory compound, FR167653, ameliorates crescentic glomerulonephritis in Wistar-Kyoto rats

The pathophysiologic effects of FR167653 were investigated in a model of crescentic glomerulonephritis induced by a small dose of nephrotoxic serum in Wistar-Kyoto rats. The rats developed crescentic glomerulonephritis by 6 d after the administration of serum. The subcutaneous administration of FR167653 (32 mg/kg) markedly decreased the severity of the renal damage. In a group of rats treated with FR167653 daily from day 0 to day 6, glomerular damage, including crescent formation and proteinuria, was virtually absent. FR167653 markedly decreased urinary levels of monocyte chemoattractant protein-1 (MCP-1). In addition, FR167653 reduced production of MCP-1 protein and transcripts in the diseased kidneys. In a group of rats for which treatment was initiated on day 3, shortly after the appearance of glomerular abnormalities, the progression of renal disease was appreciably retarded, with partial inhibition of MCP-1. In contrast, when rats were treated only on the first day, no beneficial effects were observed and severe proliferative and necrotizing glomerulonephritis, with crescent formation, was induced by day 6, with the upregulation of MCP-1. These results suggest that FR167653 may be effective against crescentic glomerulonephritis, possibly via the inhibition of MCP-1. In addition, there was marked reduction in renal injury even when FR167653 treatment was initiated after glomerular inflammation was established, suggesting that the therapeutic application of FR167653 may be clinically useful for human renal diseases.

MIP-1alpha and MCP-1 contribute to crescents and interstitial lesions in human crescentic glomerulonephritis

BACKGROUND

The precise molecular mechanisms of macrophage (Mphi) recruitment and activation in crescentic glomerulonephritis remain to be investigated. We hypothesized that locally produced macrophage inflammatory protein (MIP)-1alpha and monocyte chemoattractant protein (MCP)-1 via the chemokine receptors participate in the pathophysiology of human crescentic glomerulonephritis by recruiting and activating Mphi.

METHODS

We investigated the levels of MIP-1alpha and MCP-1 by enzyme-linked immunosorbent assay (ELISA) in 20 healthy subjects, 20 patients with crescentic glomerulonephritis, and 41 control patients with various other renal diseases. The presence of MIP-1alpha, MCP-1, and the cognate chemokine receptor for MIP-1alpha, CCR5, in the diseased kidneys was evaluated by immunohistochemical and in situ hybridization analyses.

RESULTS

MIP-1alpha-positive cells were mainly detected in crescentic lesions, whereas MCP-1 was mainly in the interstitium. In addition, we detected CCR5-positive cells in diseased glomeruli and interstitium. Urinary MIP-1alpha was detected in crescentic glomerulonephritis, even though it was below detectable levels in healthy subjects and in patients with other renal diseases without crescents. Urinary MIP-1alpha levels in the patients with crescentic glomerulonephritis were well correlated with the percentage of cellular crescents and the number of CD68-positive infiltrating cells and CCR5-positive cells in the glomeruli. However, urinary MCP-1 levels were well correlated with the percentage of both total crescents and fibrocellular/fibrous crescents and the number of CD68-positive infiltrating cells in the interstitium. Moreover, elevated urinary levels of both MIP-1alpha and MCP-1 dramatically decreased during glucocorticoid therapy-induced convalescence.

CONCLUSIONS

These observations suggest that locally produced MIP-1alpha may be involved in the development of cellular crescents in the acute phase via CCR5 and that MCP-1 may be involved mainly in the development of interstitial lesions in the chronic phase when fibrocellular/fibrous crescents are present, possibly through Mphi recruitment and activation.

Amyloid goiter presented as a subacute thyroiditis-like symptom in a patient with hypersensitivity vasculitis

We present a 25-year-old woman with amyloid goiter due to hypersensitivity vasculitis, who developed transient thyrotoxicosis resembling subacute thyroiditis. She received prednisolone (20 mg/ day) for three years for hypersensitivity vasculitis, and was diagnosed as having secondary amyloidosis by biopsies of the stomach, rectum and kidneys. She noticed neck swelling with severe right neck tenderness, palpitation, hyperhidrosis and weight loss. An elastic firm diffuse goiter was palpable, and the upper pole of the right lobe was extremely tender. Her serum free T4 and T3 levels were high, and the serum TSH was suppressed to subnormal. She was positive for serum C-reactive protein. Anti-thyroidal autoantibodies were all negative. Her thyrotoxicosis subsided spontaneously within one week. Serum titers of antibodies to various viruses were unchanged during the clinical course for two weeks, but she was positive for HLA B35. Examination of a needle-biopsy specimen of the thyroid gland showed extensive amyloid deposition and no evidence of subacute thyroiditis. We considered her transient thyrotoxicosis to be associated with amyloid goiter. The clinical course of this case was similar to the subacute thyroiditis-like syndrome, first described by Ikenoue et al. When patients with primary or secondary amyloidosis have symptoms and signs of subacute thyroiditis, but develop an unusual course, amyloid goiter should be considered.

Tumor necrosis factor receptor p55 is essential for intrahepatic granuloma formation and hepatocellular apoptosis in a murine model of bacterium-induced fulminant hepatitis

Accumulating evidence implicates tumor necrosis factor (TNF) and Fas systems in liver injury, although the interaction between these two systems remains to be investigated. In this study, we examined Propionibacterium acnes-primed TNF receptor p55-deficient (TNFRp55-/-) or Fas-deficient MRL/MpJ Lpr/Lpr mice challenged with lipopolysaccharide (LPS). Priming with P. acnes caused mononuclear cell infiltration into the hepatic lobules and granuloma formation in the livers of TNFRp55 wild-type mice. Subsequent LPS challenge caused massive liver injury and a marked increase in transaminase levels, leading to acute lethality in control wild-type mice. In contrast, the same treatment caused few pathological changes in livers of TNFRp55-/- mice, and all animals survived. P. acnes and subsequent LPS challenge induced granuloma formation and apoptotic changes, respectively, in livers of MRL/MpJ Lpr/Lpr mice. However, liver injury was 50% of that in control MRL/MpJ +/+ mice, suggesting some role of the Fas-Fas ligand system in this liver injury model. On the other hand, an agonistic anti-Fas antibody caused massive apoptosis and hemorrhagic changes of the liver without any priming with P. acnes, leading to death in both TNFRp55-/- and control wild-type mice. These results suggest that TNFRp55 but not Fas was involved in P. acnes-induced granuloma formation as well as subsequent LPS-induced liver injury and that TNFRp55 and Fas independently induced apoptosis of hepatocytes in vivo.

Intervention of crescentic glomerulonephritis by antibodies to monocyte chemotactic and activating factor (MCAF/MCP-1)

We investigated the pathophysiological role of a potent macrophage (M(phi)) chemotactic cytokine (chemokine), monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 (MCAF/MCP-1), in an animal model of crescentic glomerulonephritis. Administration of a small dose of nephrotoxic sera induced severe proliferative and necrotizing glomerulonephritis, with crescentic formation in the early phase and glomerulosclerosis in the later phase, in Wistar-Kyoto rats. MCAF/MCP-1 protein was detected immunohistochemically in glomeruli, vascular endothelial cells, and tubular epithelial cells in the early phase of injured kidney tissues but not in normal ones. Anti-MCAF/MCP-1 antibodies decreased the number of M(phi) in glomeruli, and prevented crescentic formation and the fusion of epithelial cell foot process in nephritic rats, thereby decreasing the excreted amounts of protein to normal levels on days 3 and 6. Furthermore, anti-MCAF/MCP-1 antibodies remarkably reduced glomerulosclerosis and improved renal dysfunction as well as proteinuria in the later phase (56 days). These results indicate that MCAF/MCP-1 essentially participates in the impairment of renal functions associated with crescentic glomerulonephritis by recruiting and activating M(phi).

Acid proteinases of the fore-gut in metamorphosing tadpoles of Rana catesbeiana

1. Two types of acid proteinases were found in the adult stomach of the bullfrog, Rana catesbeiana. 2. The first type of enzyme appeared in the developing stomach and esophagus and contained more than two kinds of acid proteinases. 3. These enzymes were identified as pepsin-type enzymes. 4. The second type of enzyme existed from the larva to adult stage and was also present in the adult duodenum. 5. This enzyme was different from pepsin and thought to be cathepsin E.