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Background/Aims: Nephropathy related with renin can be alleviated with ACE-inhibitors or AT1R blockers, whereas they might be ineffective after long-term administration because of a feedback production of enhanced renin. Therefore, it is urgent to develop a new category of anti-nephropathy medicine directly targeting renin. Riligustilide (C20), originally isolated from the Chinese herb Ligusticumporteri, a rhizome, was confirmed effective against many diseases. Methods: The therapeutic effect of C20 on renal injury and its underlying mechanism were investigated in three different nephrotic models, which were spontaneously hypertension rats (SHR) model, diabetic nephropathy in BTBR ob/ob mice model and 5/6-nephrectomized (5/6NX) rats model. Results: The intensity of kidney fibrosis was extensively decreased in the C20-treated rats compared to the vehicle animals. C20 significantly alleviated renal injury much more in 5/6 NX rats than in vehicle group. The rats in 5/6 NX without administrated C20 developed albuminuria earlier with more severe symptoms. Additionally, our findings showed that C20 down-regulated the renin expression and relocation of CREB-CBP complex in vivo and in vitro. Conclusion: C20 plays importantly reno-protective roles most likely through the relocation of CREB-CBP complex. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is a significant global public health problem depicting a rising prevalence worldwide. As a serious complication of diabetes, diabetes-associated cognitive decline is attracting increasing attention. However, the underlying mechanisms are yet to be fully determined. Both endoplasmic reticulum (ER) stress and autophagy have been reported to modulate neuronal survival and death and be associated with several neurodegenerative diseases. Here, a streptozotocin-induced diabetic mouse model and primary cultured mouse hippocampal neurons were employed to investigate the possible role of ER stress and autophagy in diabetes-induced neuronal apoptosis and cognitive impairments, and further explore the potentialmolecular mechanisms. ER stress markers GRP78 and CHOPwere both enhanced in diabetic mice, as was phosphorylation of PERK, IRE1a, and JNK. In addition, the results indicated an elevated level of autophagy in diabetic mice, as demonstrated by up-regulated expressions of autophagy markers LC3-II, beclin 1 and down-regulated level of p62, and increased formation of autophagic vacuoles and LC3-II aggregates. Meanwhile, we found that these effects could be abolished by ER stress inhibitor 4-phenylbutyrate or JNK inhibitor SP600125 in vitro. Furthermore, neuronal apoptosis of diabetic mice was attenuated by pretreatment with 4-phenylbutyrate, while aggravated by application of inhibitor of autophagy bafilomycin A1 in vitro. These results suggest that ER stress pathway may be involved in diabetes-mediated neurotoxicity and promote the following cognitive impairments. More important, autophagy was induced by diabetes possibly through ER stress-mediated JNK pathway, which may protect neurons against ER stress-associated cell damages. [ABSTRACT FROM AUTHOR]

Background: The association between serum selenium level and gestational diabetes mellitus (GDM) is controversial. The aim of our study was to systematically review available literature linking selenium to GDM for a comprehensive understanding of the relationship between serum selenium level and GDM in human. Methods: PubMed, The Cochrane Library and Medline were searched for studies published up to August 2016. Manual searches of references of the relevant original studies were carried out. Pooled estimates were measured using the fixed or random effect model. Overall effect was reported in a standard mean difference (SMD). All data were analyzed with Review Manager 5.3 and Stata 12.0. Results: Of 44 references reviewed, seven studies involving 569 patients met our inclusion criteria and contributed to meta-analysis. All the studies were used to evaluate the relationship between serum selenium level and GDM. Selenium level was significantly lower in women with GDM than those without GDM (SMD = -1.17; 95% CI: -1.98 to -0.35, P = 0.005). Subgroup analysis showed that such trend was consistent within the non-Caucasian population (Asia: SMD = -2.82; 95% CI: -5.21 to -0.43, P = 0.02; Africa: SMD = -0.56; 95% CI: -1.07 to -0.05, P = 0.03) and in the third trimester (SMD = -1.78; 95% CI: -3.04 to -0.52, P = 0.006), but not within the Caucasian population (Europe: SMD = -0.6; 95% CI: -1.98 to 0.78, P = 0.39) or in the second trimester (SMD = -0.68; 95% CI: -1.6 to 0.25, P = 0.15). Conclusions: The available evidences suggested that serum selenium level was lower in women with GDM than those with normal glucose tolerance, especially within the non-Caucasian population and in the third trimester. However, well-designed prospective studies are needed to understand dynamic associations between selenium status and GDM risk. [ABSTRACT FROM AUTHOR]

Background Postoperative cognitive dysfunction is increasingly recognized as an important clinical syndrome. Inhalation anesthetics are commonly used during surgery, and it has been proposed that inhalation anesthetics impair cognitive function. However, there are few clinical interventions and treatments available to prevent this disorder. GTS-21, a selective agonist of alpha 7 nicotinic acetylcholine receptor, has been indicated to exert neuroprotective effects in the experimental animal models of neurodegenerative diseases. Therefore, we hypothesized that pretreatment with GTS-21 attenuates isoflurane-induced cognitive decline in aged rats. Methods In the present study, 20-mo-old rats were administered GTS-21or an equal volume of saline by intraperitoneal injection 30 min before exposure to isoflurane. Then the rats were exposed to 1.3% isoflurane for 4 h. Spatial learning and memory of the rats were assessed at 2 wk after isoflurane exposure. The expression levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-a in the hippocampus and cerebral cortex were determined by enzyme-linked immunosorbent assay. Simultaneously, neuronal apoptosis in the hippocampus was also observed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and Nissl staining. Results We found that exposure to isoflurane induces learning and memory deficits of old rats. IL-1β in the hippocampus was increased at 4 h after isoflurane exposure. Isoflurane also increased neuroapoptosis in the hippocampus and decreased neuronal density in the CA1 region. And GTS-21 pretreatment effectively alleviated these changes. Conclusions The study demonstrated that pretreatment with a7 nicotinic acetylcholine receptor agonist GTS-21 attenuates isoflurane-induced learning and memory impairment in aged rats. [ABSTRACT FROM AUTHOR]

Leptin is an adipose tissue-derived hormone that plays a critical role in energy homeostasis. Vitamin D has been shown to regulate energy metabolism, but the relationship between vitamin D and leptin is unclear. Leptin expression and secretion was reduced in vitamin D receptor (VDR)-null mice and increased in transgenic (Tg) mice overexpressing the VDR in adipocytes; however, as leptin is mainly determined by fat mass, it is unclear whether the vitamin D hormone directly regulates leptin expression. To address this question, we determined the effect of vitamin D on leptin expression in vivo and ex vivo. One-week treatment of WT mice with the vitamin D analog RO-27-5646 led to a significant increase in adipose leptin mRNA transcript and serum leptin levels. Moreover, in adipose tissue cultures, 1,25-dihydroxyvitamin D markedly stimulated mRNA expression and secretion of leptin, but not resistin, in adipose tissues obtained from WT mice, but not from VDR-null mice, and leptin upregulation induced by 1,25-dihydroxyvitamin D was more robust in adipose tissues obtained from VDR Tg mice compared with WT mice. These data demonstrate that 1,25-dihydroxyvitamin D stimulates adipose leptin production in a VDR-dependent manner, suggesting that vitamin D may affect energy homeostasis through direct regulation of leptin expression. [ABSTRACT FROM AUTHOR]

Our previous studies demonstrated a high fat diet-resistant lean phenotype of vitamin D receptor (VDR)-null mutant mice mainly due to increased energy expenditure, suggesting an involvement of the VDR in energy metabolism. Here, we took a transgenic approach to further define the role of VDR in adipocyte biology. We used the aP2 gene promoter to target the expression of the human (h) VDR in adipocytes in mice. In contrast to the VDR-null mice, the aP2-hVDR Tg mice developed obesity compared with the wild-type counterparts without changes in food intake. The increase in fat mass was mainly due to markedly reduced energy expenditure, which was correlated with decreased locomotive activity and reduced fatty acid β-oxidation and lipolysis in the adipose tissue in the transgenic mice. Consistently, the expression of genes involved in the regulation of fatty acid transport, thermogenesis, and lipolysis were suppressed in the transgenic mice. Taken together, these data con- firm an important role of the VDR in the regulation of energy metabolism. [ABSTRACT FROM AUTHOR]

The isobaric vapor−liquid equilibrium (VLE) data of the binary system N,N-dimethylaniline 2-amino-3-methylpyridine were collected at (5.158 and 8.041) kPa. The activity coefficients of the system were correlated with the Van Laar and UNIQUAC models. The results showed that the calculated values of the vapor phase mole fraction and boiling temperature by the two models agreed well with the experimental data. Furthermore, the activity coefficients at infinite dilution were also presented. The VLE data were shown to be thermodynamically consistent by both the Herington consistency and point consistency tests. [ABSTRACT FROM AUTHOR]

We have investigated the molecular mechanism whereby 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] inhibits adipogenesis in vitro. 1,25(OH)2D3 blocks 3T3-L1 cell differentiation into adipocytes in a dose-dependent manner; however, the inhibition is ineffective 24–48 h after the differentiation is initiated, suggesting that 1,25(OH)2D3 inhibits only the early events of the adipogenic program. Treatment of 3T3-L1 cells with 1,25(OH)2D3 does not block the mitotic clonal expansion or C/EBPβ induction; rather, 1,25(OH)2D3 blocks the expression of C/EBPα, peroxisome proliferator-activated receptor-γ (PPARγ), sterol regulatory element-binding protein-l, and other downstream adipocyte markers. The inhibition by 1,25(OH)2D3 is reversible, since removal of 1,25(OH)2D3 from the medium restores the adipogenic process with only a temporal delay. Interestingly, although the vitamin D receptor (VDR) protein is barely detectable in 3T3-L1 preadipocytes, its levels are dramatically increased during the early phase of adipogenesis, peaking at 4–8 h and subsiding afterward throughout the rest of the differentiation program; 1,25(OH)2D3 treatment appears to stabilize the VDR protein levels. Consistently, adenovirus-mediated overexpression of human (h) VDR in 3T3-L1 cells completely blocks the adipogenic program, confirming that VDR is inhibitory. Inhibition of adipocyte differentiation by 1,25(OH)2D3 is ameliorated by troglitazone, a specific PPARγ antagonist; conversely, hVDR partially suppresses the transacting activity of PPARγ but not of C/EBPβ or C/EBPα. Moreover, 1,25(OH)2D3 markedly suppresses C/EBPα and PPARγ mRNA levels in mouse epididymal fat tissue culture. Taken together, these data indicate that the blockade of 3T3-L1 cell differentiation by 1,25(OH)2D3 occurs at the postclonal expansion stages and involves direct suppression of C/EBPα and PPARγ upregulation, antagonization of PPARγ activity, and stabilization of the inhibitory VDR protein. [ABSTRACT FROM AUTHOR]

We recently showed that vitamin D receptor (VDR) inactivation results in deregulated stimulation of the renin-angiotensin system (RAS). To address further the relation between RAS activation and the abnormalities in electrolyte and volume homeostasis, we studied the effect of the ANG II type I receptor antagonist losartan and the angiotensin-converting enzyme inhibitor captopril on VDR-null mice. Treatment with losartan or captopril normalized the water intake and urine excretion of VDR-null mice. However, the increase in salt excretion in VDR-null mice was not affected by either drug, suggesting that this abnormality is independent of the RAS. Northern blot and immunohistochemical analyses revealed that both drugs caused a drastic stimulation of renin expression in wild-type and VDR-null mice, but renin expression remained much higher in the treated VDR-null mice than in the treated wild-type mice, suggesting that the ANG II feedback mechanism remains intact in the mutant mice. These data firmly established a causative relation between RAS overstimulation and the abnormal volume homeostasis in VDR-null mice and demonstrated that vitamin D repression of renin expression is independent of the ANG II feedback regulation in vivo. [ABSTRACT FROM AUTHOR]

Presents a study which examined the mechanism involved in the inverse relationship between vitamin D levels and the blood pressure and/or plasma renin activity. Role of renin-angiotensin system in the regulation of blood pressure, electrolyte and volume homeostasis; Analysis of vitamin D receptor-null mice; Consequence of the inhibition of 1,25 (OH)[sub2]D[sub3] biosynthesis; Link between the elevation of renin expression and hypocalcemia.

Cisplatin (DDP) is a potent chemotherapeutic; however, it can also cause acute kidney injury (AKI). Because of the complexity of the toxicity it induces, few effective methods exist for ameliorating any form of DDP-induced AKI. Recent research has suggested that the complement system is a potential molecular target for such amelioration. In the study here, in vivo (male ICR mice) and in vitro (HK-2 cells) models of DDP-induced AKI were established to investigate the potential therapeutic effects of Vitamin D (VD) against this form of AKI. Endpoints assessed in vivo/in vitro included overall renal function, degree of renal damage, and complement receptor C5aR expression using histology, immunohistochemistry, immunofluorescence, RT-PCR, and Western blots. The data indicated that the use of VD treatment could reduce renal pathological damage along with expression of TNFα, IL-1b, IL-18, and C5aR; however, an over-expression of C5aR weakened the protective effects of VD/VD receptor (VDR) against oxidative damage and inflammatory cell infiltration. Using a luciferase reporter gene assay and ChIP analysis, it was demonstrated that C5aR was transcriptionally inhibited by VDR. In conclusion, VD/VDR could delay DDPinduced AKI by inhibiting the expression of C5aR through transcriptional regulation and reducing the production of downstream pro-inflammatory cytokines. The present study revealed the regulatory mechanism of VD/VDR in acute renal inflammation and provides new insights into its therapeutic function in DDP-induced AKI. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article on ischemic postconditioning during primary percutaneous coronary intervention in volume 128.

Phospholipase D (PLD) is a critical component of intracellular signal transduction and has been implicated in many important biological processes. It has been observed that there are abnormalities in PLD expression in many human cancers, and PLD is thus recognized as a potential diagnostic biomarker as well as a target for drug discovery. We report for the first time a phospholipid-modified nanoprobe for ratiometric upconversion fluorescence (UCF) sensing and bioimaging of PLD activity. The nanoprobe can be synthesized by a facile one-step self-assembly of a phospholipid monolayer composed of polyethylene glycol) PEG)ylated phospholipid and rhodamine B-labeled phospholipid on the surface of upconversion nanopartides (UCNPs) NaYF4: 20%Yb, 2%Er. The fluorescence resonance energy transfer (FRET) process from the UCF emission at 540 nm of the UCNPs to the absorbance of the rhodamine B occurs in the nanoprobe. The PLD-mediated hydrolysis of the phosphodiester bond makes rhodamine B apart from the UCNP surface, leading to the inhibition of FRET. Using the unaffected UCF emission at 655 nm as an internal standard, the nanoprobe can be used for ratiometric UCF detection of PLD activity with high sensitivity and selectivity. The PLD activity in cell lysates is also detennined by the nanoprobe, confirming that PLD activity in a breast cancer cell is at least 7-fold higher than in normal cell. Moreover, the nanoprobe has been successfully applied to monitoring PLD activity in living cells by UCF bioimaging. The results reveal that the nanoprobe provides a simple, sensitive, and robust platform for point-of-care diagnostics and drug screening in biomedical applications. [ABSTRACT FROM AUTHOR]

Left ventricular hypertrophy (LVH) is causally related to increased morbidity and mortality following acute myocardial infarction (AMI) via still unknown mechanisms. Although rapamycin exerts cardioprotective effects against myocardial ischemia/reperfusion (MI/R) injury in normal animals, whether rapamycin-elicited cardioprotection is altered in the presence of LVH has yet to be determined. Pressure overload induced cardiac hypertrophied mice and sham-operated controls were exposed to AMI by coronary artery ligation, and treated with vehicle or rapamycin 10 min before reperfusion. Rapamycin produced marked cardioprotection in normal control mice, whereas pressure overload induced cardiac hypertrophied mice manifested enhanced myocardial injury, and was refractory to rapamycin-elicited cardioprotection evidenced by augmented infarct size, aggravated cardiomyocyte apoptosis, and worsening cardiac function. Rapamycin alleviated MI/R injury via ERK-dependent antioxidative pathways in normal mice, whereas cardiac hypertrophied mice manifested markedly exacerbated oxidative/nitrative stress after MI/R evidenced by the increased iNOS/gp91phox expression, superoxide production, total NO metabolites, and nitrotyrosine content. Moreover, scavenging superoxide or peroxynitrite by selective gp91phox assembly inhibitor gp91ds-tat or ONOO- scavenger EUK134 markedly ameliorated MI/R injury, as shown by reduced myocardial oxidative/nitrative stress, alleviated myocardial infarction, hindered cardiomyocyte apoptosis, and improved cardiac function in aortic-banded mice. However, no additional cardioprotective effects were achieved when we combined rapamycin and gp91ds-tat or EUK134 in ischemic/reperfused hearts with or without LVH. These results suggest that cardiac hypertrophy attenuated rapamycin-induced cardioprotection by increasing oxidative/nitrative stress and scavenging superoxide/peroxynitrite protects the hypertrophied heart from MI/R. [ABSTRACT FROM AUTHOR]

Curcumin is a natural polyphenol with powerful antioxidant and anti-inflammatory properties. The present study evaluated the protective effect of curcumin on myocardial injury in rats as well as the mechanisms underlying these effects, and examined the expression of nuclear factor-κB (NF-κB), peroxisome proliferator-activated receptor-γ (PPAR-γ) and B-cell leukemia/lymphoma-2 (Bcl-2) following myocardial infarction. A rat model of myocardial infarction was successfully established. Hematoxylin and eosin staining showed cellular atrophy and hyperchromatic cytoplasm in the myocardial infarction area. The myocardial cells displayed lysis and breakage of cardiac muscle fibers, karyopyknosis and karyorrhexis associated with infiltration of inflammatory cells and proliferation of fibrous tissue. Curcumin treatment at a dosage of 150 mg/kg/body weight resulted in an increase in surviving cells, fewer apoptotic cells, decreased proliferation of fibrous tissue and reduced infiltration of inflammatory cells, though necrosis was still present compared with the rats without curcumin treatment. The immunohistochemical assay demonstrated that curcumin treatment inhibited the expression of NF-κB, but increased the expression of PPAR-γ. The results of the reverse transcription-polymerase chain reaction indicated that curcumin treatment significantly increased the mRNA expression levels of Bcl-2 (P<0.01). Therefore, curcumin antagonizes cardiomyocyte apoptosis and inhibits inflammatory cell infiltration following myocardial infarction, which may be associated with its inhibitory effects on the expression of NF-κB, and activating effects on the expression of PPAR-γ and Bcl-2 in myocardial cells. Curcumin may be useful in clinical practice for saving more living heart muscle in the area of myocardial infarction and improving cardiac function following the elective opening of obstructed coronary arteries [ABSTRACT FROM AUTHOR]

The negative feedbackmechanism is essential tomaintain effective immunity and tissue homeostasis. 1,25-dihydroxyvitamin D (1,25[OH]2D3) modulates innate immune response, but the mechanism remains poorly understood. In this article, we report that vitamin D receptor signaling attenuates TLR-mediated inflammation by enhancing the negative feedback inhibition. Vitamin D receptor inactivation leads to hyperinflammatory response in mice and macrophage cultures when challenged with LPS, because of microRNA-155 (miR-155) overproduction that excessively suppresses suppressor of cytokine signaling 1, a key regulator that enhances the negative feedback loop. Deletion of miR-155 attenuates vitamin D suppression of LPS-induced inflammation, confirming that 1,25(OH)2D3 stimulates suppressor of cytokine signaling 1 by downregulating miR-155. 1,25(OH)2D3 downregulates bic transcription by inhibiting NF-κB activation, which is mediated by a κB cis-DNA element located within the first intron of the bic gene. Together, these data identify a novel regulatory mechanism for vitamin D to control innate immunity. [ABSTRACT FROM AUTHOR]

The multikinase inhibitor sorafenib is the first oral agent to show activity against human hepatocellular carcinoma (HCC). Although the clinical application of sorafenib has shown good tolerability in the studied populations, it also causes multiple human dose-limiting toxicities. Thus, there is a strong need to reduce the overall dose of sorafenib. We have reported that the epidermal growth factor receptor variant III (EGFRvIII) expression can decrease the sensitivity of HCC cells to chemotherapeutic drugs. Therefore, we sought to explore whether EGFRvIII can affect the sensitivity of HCC cells to sorafenib. In this study, we observed that EGFRvIII expression significantly decreased the sensitivity of HCC cells to sorafenib. To enhance the antitumor effect and reduce the overall dose of sorafenib, we evaluated the combined effects of CH12, a monoclonal antibody against EGFRvIII, and sorafenib on the growth of HCC cells expressing EGFRvIII in vitro and in vivo. The results showed that, when CH12 was combined with sorafenib, the tumor growth suppression effect was significantly increased, and the concentration of sorafenib required for growth inhibition was substantially reduced. Mechanistically, the combination could more noticeably downregulate the phosphorylation of constitutively active extracellular signal--regulated kinase (ERK), Akt (Thr308), and signal transducer and activator of transcription 3 (STAT3) than sorafenib alone. Collectively, these findings demonstrate that CH12 interacts additively with sorafenib to strongly inhibit the tumor growth of HCC xenografts expressing EGFRvIII by enhancing the sorafenib-mediated inhibition of the MEK/ERK, phosphoinositide 3-kinase/AKT, and STAT3 pathways. [ABSTRACT FROM AUTHOR]

We recently isolated an exon-4-deleted epidermal growth factor receptor (EGFR) variant, termed de4 EGFR. Because the extracellular domain alteration of receptors often influences the antitumor effect of therapeutic antibodies, it is essential to test the sensitivity of de4 EGFR+ tumors to anti-EGFR antibodies. Therefore, in this study, the antitumor activities of mAb CH12, an anti-EGFRvIII antibody developed in our laboratory, as well as a U.S. Food and Drug Administration-approved anti-EGFR antibody, cetuximab (C225), were characterized on de4 EGFR+ models. The results of FACS assays showed that CH12 bound to de4 EGFR with a higher avidity than did C225. Interestingly, CH12, but not C225, significantly inhibited the metastasis and growth of U87MG-de4 EGFR xenografts, with a growth-inhibition ratio of 46.48% in vivo, and prolonged the survival of the tumor-bearing mice by 37.2%. Treatment with CH12 significantly suppressed tumor proliferation and angiogenesis with increased tumor apoptosis. Mechanistically, de4 EGFR protein expression was virtually undetectable in the U87MG-de4 EGFR xenografts treated with CH12. This may account for the observed reduction of Akt and Erk phosphorylation, cyclin D1, Bcl-2, and Bcl-xL expression and the increase of p27 and E-cadherin expression. Intriguingly, LAMP-1, a major component of the lysosome, was significantly up-regulated in the CH12- treated group but not in the C225-treated group, suggesting its contribution to the degradation of de4 EGFR. Taken together, our data demonstrated that mAb CH12 is a promising therapeutic agent for treating de4 EGFR+ gliomas. [ABSTRACT FROM AUTHOR]

Surface molecular imprinting in particular over nanosized support materials, is very suitable for a template of bulky structure like protein. Inspired by the surface template immobilization method reported previously, we herein demonstrate an alternative strategy for enhancing specific recognition of core-shell protein-imprinted nanoparticles through pre-functionalizing the cores with noncovalent template sorption groups. For proof of this concept, silica nanoparticles chosen as the core materials were modified consecutively with 3-aminopropyltrimethoxysilane and maleic anhydride to introduce polymerizable double bonds and terminal carboxyl groups, hence capable of physically adsorbing the print protein. With lysozyme as a template, thin protein-imprinted shells were fabricated according to our newly developed approach for surface protein imprinting over nanoparticles. The rebinding experiments confirmed that the introduction of the carboxyl groups could remarkably improve the imprinting effect in relation to a significantly increased imprinting factor and specific rebinding capacity. Moreover, in contrast to the harsh template removal conditions required for the covalent template coupling approach, the template removal during the imprinted particle synthesis as well as desorption after rebinding could be mildly achieved via washing with salt solution. [ABSTRACT FROM AUTHOR]

We recently showed that losartan and paricalcitol are synergistic in the treatment of diabetic nephropathy in a model of type 1 diabetes. To test this strategy in a model of type 2 diabetes, we treated 2-month-old diabetic Lprdb/db mice with losartan, paricalcitol, or a combination of losartan and paricalcitol for 3 months. Vehicle-treated diabetic mice developed progressive albuminuria and glomerular abnormalities with mesangial expansion and glomerulosclerosis compared to their non-diabetic littermate control mice. Accompanying damage of the glomerular filtration barrier was a marked reduction in podocyte number as well as reduced expression of slit diaphragm proteins. Further, there was increased glomerular expression of extracellular matrix proteins, monocyte chemoattractant protein-1 and transforming growth factor-β. Losartan or paricalcitol each alone moderately ameliorated albuminuria and glomerular damage. However, their combined use showed a dramatic therapeutic synergism, manifested by prevention of progressive albuminuria, restoration of the glomerular filtration barrier, reversal of the decline in slit diaphragm proteins, reduced synthesis of extracellular matrix proteins, and reduction of glomerulosclerosis. These effects were accompanied by blockade of the compensatory increase of renin production and angiotensin I/II accumulation in the kidney. Thus, our study further shows that vitamin D analogs can increase the efficacy of AT1 receptor blockade, leading to a more effective prevention of kidney disease in type 2 diabetes. [ABSTRACT FROM AUTHOR]

The renin-angiotensin system (RAS) is a major mediator of renal injury in diabetic nephropathy. Our previous studies demonstrated that 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] plays a renoprotective role by suppressing the RAS, with renin and angiotensinogen (AGT) as the main targets. The mechanism whereby 1 ,25(OH)2D3 transcriptionally suppresses renin gene expression has been elucidated; however, how vitamin D regulates AGT remains unknown. Exposure of mesangial cells or podocytes to high glucose (HG; 30 mM) markedly stimulated AGT expression. In mesangial cells, the stimulation was inhibited by 1,25(OH)2D3 (20 nM) or NF-κB inhibitor BAY 11-7082, suggesting the involvement of NF-κB in HG-induced AGT expression and the interaction between 1,25(OH)2D3 and NF-κB in the regulation. Plasmid pNF-κB-Luc luciferase reporter assays showed that 1,25(OH)2D3 blocked HG-induced NF-κB activity. EMSA and ChIP assays demonstrated increased p65/p50 binding to a NF-κB binding site at -1734 in the AGT gene prumoter upon high glucose stimulation, and the binding was disrupted by 1,25(OH)2D3 treatment. Overexpression of p65/p50 overcame 1,25(OH)2D3 suppression, and mutation of this NF-κB binding site blunted 1,25(OH)2D3 suppression of the promoter activity. In mice lacking the vitamin D receptor, AGT mRNA expression in the kidney was markedly increased compared with wild-type mice, and AGT induction in diabetic mice was suppressed by treatment with a vitamin D analog. These data indicate that 1,25(OH)2D3 suppresses hyperglycemia-induced AGT expression by blocking NF-κB-mediated pathway. [ABSTRACT FROM AUTHOR]

Recent studies have established that vitamin D plays multiple biological roles beyond calcium metabolism; however, whether vitamin D is involved in energy metabolism is unknown. To address this question, we characterized the metabolic phenotypes of vitamin D receptor (VDR)-null mutant mice. Under a normocalcemic condition, VDR-null mice displayed less body fat mass and lower plasma triglyceride and cholesterol levels compared with wild-type (WT) mice; when placed on a high-fat diet, VDR-null mice showed a slower growth rate and accumulated less fat mass globally than WT mice, even though their food intake and intestinal lipid transport capacity were the same as WT mice. Consistent with the lower adipose mass, plasma leptin levels were lower and white adipocytes were histologically smaller in VDR-null mice than WT mice. The rate of fatty acid β-oxidation in the white adipose tissue was higher, and the expression of uncoupling protein (UCP) 1, UCP2 and UCP3 was markedly upregulated in VDR-null mice, suggesting a higher energy expenditure in the mutant mice. Experiments using primary brown fat culture confirmed that 1 ,25-dihydroxyvitarnin D1 directly suppressed the expression of the UCPs. Consistently, the energy expenditure, oxygen consumption, and CO2 production in VDR-null mice were markedly higher than in WT mice. These data indicate that vitamin D is involved in energy metabolism and adipocyte biology in vivo in part through regulation of β-oxidation and UCP expression. [ABSTRACT FROM AUTHOR]

The renin-angiotensin system (RAS) plays a critical role in the development of diabetic nephropathy, and blockade of the RAS is currently used for treatment of diabetic nephropathy. One major problem for the current RAS inhibitors is the compensatory renin increase, which reduces the efficacy of RAS inhibition. We have shown that vitamin D exerts renoprotective actions by transcriptionally suppressing renin. Here we demonstrated that combination therapy with an AT1 receptor blocker and a vitamin D analog markedly ameliorated renal injury in the streptozotocin (STZ)-induced diabetes model due to the blockade of the compensatory renin rise by the vitamin D analog, leading to more effective RAS inhibition. STZ-treated diabetic DBA/2J mice developed progressive albuminuria and glomerulosclerosis within 13 weeks, accompanied by increased intrarenal production of angiotensin (Ang) II, fibronection, TGF-β, and MCP-1 and decreased expression of slit diaphragm proteins. Treatment of the diabetic mice with losartan or paricalcitol (19-nor-1,25-dihydroxyvitamin D[sub2], an activated vitamin D analog) alone moderately ameliorated kidney injury; however, combined treatment with losartan and paricalcitol completely prevented albuminuria, restored glomerular filtration barrier structure, and markedly reduced glomerulosclerosis. The combined treatment suppressed the induction of fibronection, TGF-β, and MCP-1 and reversed the decline of slit diaphragm proteins nephrin, Neph-1, ZO-1, and α-actinin-4. These were accompanied by blockade of intrarenal renin and Ang II accumulation induced by hyperglycemia and losartan. These data demonstrate that inhibition of the RAS with combination of vitamin D analogs and RAS inhibitors effectively prevents renal injury in diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Transforming growth factorß1 (TGFß1) is considered to be the principal contributor to liver fibrosis. So in this study the ribozymes against TGFß1 were designed. The in vitro cleavage activities of the ribozymes were assayed through incubation of 32 p-labeled target RNAs and 32 p-labeled ribozymes in different conditions. HSC-T6 cells were transfected with the eukaryotic constructs encoding ribozyme and disable ribozyme, then the stable cell clones were used to evaluate its antifibrotic characteristic through the effect of ribozyme on biological character of activated hepatic stellate cells (HSCs). The results demonstrated that two ribozymes (Rz803 and Rz1395) could cleave target RNAs into expected products effectively, Rz803 possessed better cleavage activity in vitro. Stable transfection of Rz803 into activated HSCs reduced TGFß1 expression in mRNA and protein level efficiently. The further studies demonstrated that Rz803 reduced deposition of collagen I, suppressed HSC proliferation, but had no effect on HSC activation in transfected HSC-T6 cells. Therefore, it indicated that Rz803 could reverse the character of activated HSCs by down-regulating TGFß1 expression efficiently and diminishing TGFß1 signaling underlying activation of hepatic stellate cells. As the consequence, it would provide a potential therapeutic approach for liver fibrosis. IUBMB Life, 57: 31–39, 2005 [ABSTRACT FROM AUTHOR]

Calbindin (CaBP)-D28k and CaBP-D9k are cytosolic vitamin D-dependent calcium-binding proteins long thought to play an important role in transepithelial calcium transport. However, recent genetic studies suggest that CaBP-D28k is not essential for calcium metabolism. Genetic ablation of this gene in mice leads to no calcemic abnormalities. Genetic inactivation of the vitamin D receptor (VDR) gene leads to hypocalcemia, secondary hyperparathyroidism, rickets, and osteomalacia, accompanied by 90% reduction in renal CaBP-D9k expression but little change in CaBP-D28k. To address whether the role of CaBP-D28k in calcium homeostasis is compensated by CaBP-D9k, we generated VDR/CaBP-D28k double knockout (KO) mice, which expressed no CaBP-D28k and only 10% of CaBP-D9k in the kidney. On a regular diet, the double KO mice were more growth-retarded and 42% smaller in body weight than VDRKO mice and died prematurely at 2.5-3 months of age. Compared with VDRKO mice, the double KO mice had higher urinary calcium excretion and developed more severe secondary hyperparathyroidism and rachitic skeletal phenotype, which were manifested by larger parathyroid glands, higher serum parathyroid hormone levels, much lower bone mineral density, and more distorted growth plate with more osteoid formation in the trabecular region. On high calcium, high lactose diet, blood-ionized calcium levels were normalized in both VDRKO and the double KO mice; however, in contrast to VDRKO mice, the skeletal abnormalities were not completely corrected in the double KO mice. These results directly demonstrate that CaBP-D28k plays a critical role in maintaining calcium homeostasis and skeletal mineralization and suggest that its calcemic role can be mostly compensated by CaBP-D9k. [ABSTRACT FROM AUTHOR]