Neutralizing anti-IFN-γ IgG was increased in patients with systemic lupus erythematosus and associated with susceptibility to infection

OBJECTIVES

Systemic lupus erythematosus (SLE) is a complicated autoimmune disease, in which infection is a leading cause of death. Some SLE patients clinically presented with recurrent and refractory infections, which manifested as adult-onset immunodeficiency syndrome due to the production of anti-interferon-γ (anti-IFN-γ) autoantibodies. This study aimed to investigate the role of anti-IFN-γ autoantibodies concerning severe infections in SLE patients.

METHODS

We detected serum levels of anti-IFN-γ IgG/IgM isotypes in SLE patients with severe infections (n = 55), SLE patients without severe infections (n = 120), rheumatoid arthritis (n = 24), ankylosing spondylitis (n = 24), and healthy controls (n = 60). The relationship between anti-IFN-γ autoantibodies and clinical characteristics and laboratory parameters were analyzed. We further evaluated the neutralizing ability of anti-IFN-γ IgG.

RESULTS

The level of anti-IFN-γ IgG was significantly elevated in SLE patients with severe infections compared with the other groups (all p < 0.01), and the positive rates of anti-IFN-γ IgG in SLE patients with and without severe infections were 29.1% and 10.8%, respectively. Further analysis indicated that the levels of anti-IFN-γ IgG were positively associated with the SLEDAI score (r = 0.6420, p < 0.001), and it could predict the susceptibility to severe infections in SLE patients. Moreover, the inhibition and function assay showed that purified IgG from anti-IFN-γ IgG-positive SLE patients could neutralize IFN-γ, and further impair IFN-γ-induced STAT1 phosphorylation.

CONCLUSIONS

The neutralizing anti-IFN-γ IgG might increase the susceptibility to infection in SLE patients, which has important implications for the treatment. Key Points • The role of anti-IFN-γ autoantibodies concerning severe infections in SLE patients remains unknown. • The results of this study reveals that anti-IFN-γ IgG levels were significantly elevated in SLE patients with severe infections. • This study suggests that neutralizing anti-IFN-γ IgG might increase the susceptibility to infection in SLE patients.

The amino acid variants in HLA II molecules explain the major association with adult-onset Still's disease in the Han Chinese population

Adult-onset Still's disease (AOSD) is a rare autoinflammatory disease with systemic involvement, and its pathophysiology remains unclear. Genome-wide association studies (GWAS) in the Chinese population have revealed an association between AOSD and the major histocompatibility complex (MHC) locus; however, causal variants in the MHC remain undetermined. In the present study, we identified independent amino-acid polymorphisms in human leukocyte antigen (HLA) molecules that are associated with Han Chinese patients with AOSD by fine-mapping the MHC locus. Through conditional analyses, we identified position 34 in HLA-DQα1 (p = 1.44 × 10^-14) and Asn in HLA-DRβ1 position 37 (p = 5.12 × 10^-11) as the major determinants for AOSD. Moreover, we identified the associations for three main HLA class II alleles: HLA-DQB1*06:02 (OR = 2.70, p = 3.02 × 10^-14), HLA-DRB1*15:01 (OR = 2.44, p = 3.66 × 10^-13), and HLA-DQA1*01:02 (OR = 1.97, p = 1.09 × 10^-9). This study reveals the relationship between functional variations in the class II HLA region and AOSD, implicating the MHC locus in the pathogenesis of AOSD.

Clinical performance of automated chemiluminescent methods for anticardiolipin and anti-β2-glycoprotein I antibodies detection in a large cohort of Chinese patients with antiphospholipid syndrome

INTRODUCTION

To assess the clinical performance and correlations of automated chemiluminescence assay (CIA) and enzyme-linked immunosorbent assay (ELISA) for detecting antiphospholipid (aPL) antibodies in the diagnosis of antiphospholipid syndrome (APS).

METHODS

The study recruited 505 subjects, including 192 with APS, 193 with connective tissue diseases other than APS, and 120 healthy donors. We measured anticardiolipin (aCL) and anti-β2-glycoprotein I (anti-β2GPI) antibodies IgG, IgM, and IgA in all the samples using both CIA and ELISA.

RESULTS

Total agreement between the two methods ranged from 83.50% for anti-β2GPI IgG antibodies to 92.76% for anti-β2GPI IgM antibodies in all the groups. Anti-β2GPI and aCL IgG assays showed the highest Spearman's rho coefficients (anti-β2GPI IgG = 0.742, aCL IgG = 0.715). Anti-β2GPI IgG CIA showed the highest sensitivity for diagnosis of APS at 80.21%, which was significantly higher than the sensitivity of anti-β2GPI IgG ELISA (52.08%). For diagnosis of APS, anti-β2GPI IgG CIA had the best discrimination power with the area under the curves (AUC) of 0.922, followed by aCL IgG CIA (AUC of 0.905). While the CIA AUC was slightly higher in all cases, the difference was not statistically significant.

CONCLUSION

CIA measurements had a good agreement and correlation with comparative ELISA assays. The CIA anti-β2GPI IgG however was significantly more sensitive for APS diagnosis. The two assay methodologies showed comparable predictive powers and support the value of the CIA method for improved diagnosis and management of patients with APS.

Clinical features and current treatments of adult-onset Still's disease: a multicentre survey of 517 patients in China

OBJECTIVES

As a rare systemic autoinflammatory disease, adult-onset Still's disease (AOSD) has heterogeneous clinical manifestations, response to treatment and outcome. This study tried to assess the clinical characteristics, laboratory tests, and treatments of Chinese AOSD patients, and make a retrospective analysis.

METHODS

We collected from 7 hospitals in China a total of 517 Chinese patients with AOSD who satisfied the Yamaguchi criteria. We retrospectively evaluated their clinical features, laboratory tests, treatments and compared them with published data from different studies. All the data in this study were from medical records and further statistic analyses.

RESULTS

We evaluated a total of 517 AOSD patients, 72% female, average age of onset was 37.7; spiking fever, rash and arthralgia occurred in 472 (91.3%), 413 (79.9%), 378 (73.1%) cases, respectively. There were 439/513 (85.6%) cases with leukocytosis and 456/476 (95.8%) cases with raised serum ferritin. The highest frequently used medications and regimens for remission were glucocorticoids (498/517, 96.3%), methotrexate (273/517, 52.8%) and hydroxychloroquine (174/517, 33.7%). 84.4%. 357/423 of AOSD cases were able to achieve initial remission with different regimens, mostly including glucocorticoids, methotrexate or hydroxychloroquine. 47.2% of them (244/517) received 30<D≤60 mg/d of prednisone to reach final clinical remission. Further analysis indicated that risk factors, such as skin rash, pericarditis, splenomegaly and delayed diagnosis, are highly related to the dosage of prednisone for remission.

CONCLUSIONS

Glucocorticoids are mostly selected to induce remission in China and half of them required ~0.5-1mg/kgbw prednisone. In patients with skin rash, pericarditis, splenomegaly or delayed diagnosis, a higher dosage of prednisone was needed to obtain remission.

Hydroxychloroquine Improves Obesity-Associated Insulin Resistance and Hepatic Steatosis by Regulating Lipid Metabolism

The burden of obesity and associated cardiometabolic diseases has been considered as an important risk factor for lupus patients. Therefore, whether obesity is involved in the over-activation of autoimmune response has attracted more and more attention. Hydroxychloroquine is a synthetic antimalarial drug and has been the clinical treatment of rheumatic diseases irreplaceable first-line drugs. Hydroxychloroquine has been suggested to have beneficial effects on lipids and insulin sensitivity, which may contribute in lowering high cardiovascular risk in SLE patients. However, its mechanism on insulin sensitivity and lipid disorders is far from being completely understood. In the present study, the therapeutic effects of hydroxychloroquine were evaluated under pathological conditions in vivo. Obesity was induced in C57BL/6 mice fed with high-fed diet, or in mice fed with high-fat diet and hydroxychloroquine. In addition, healthy mice that received normal chow diet were also monitored. The present results revealed that hydroxychloroquine reduced weight, hepatic steatosis, glucose, and insulin resistance. Furthermore, hydroxychloroquine downregulated the expression of peroxisome proliferator-activated receptor gamma in the liver. According to these present results, genes about lipid metabolism went down in high-fat mice liver. Hydroxychloroquine shows potential in ameliorating obesity-induced pathology, which acts though PPARγ to facilitate the healthy function of hepatic tissues. This evidence shows that hydroxychloroquine plays a role in improving obesity-induced lipotoxicity and insulin resistance though the peroxisome proliferator-activated receptor gamma pathway.

Endophenotypes: A conceptual link between anorexia nervosa and autism spectrum disorder

The paper, by translating the concept and the two models of endophenotype (EP), strengthens the hypothesis that there exists a linkage between anorexia nervosa (AN) and autism spectrum disorder (ASD). Specifically, the paper synthesizes empirical research that supported the idea that individuals with AN and individuals with ASD share similarities with respect to their neurocognitive EPs and temperament EPs. The paper then introduces an innovative structure to emphasize the subtle difference between neurocognitive EPs and temperament EPs in relation to AN and ASD. This structure constitutes the categorization of the shared neurocognitive EPs to the liability-index model of EP and the shared temperament EPs to the mediational model of EP. The paper argues that the shared neurocognitive EPs under the liability index model of EP are trait markers signaling the effects of genes on the phenotypes of AN and ASD; whereas, the shared temperament EPs under the mediational model of EP are state markers describing the symptomatic status of AN and ASD. The proposition of the paper suggests clinicians and researchers should target the atypical state markers (i.e., temperament EPs) shared between AN and ASD when tailoring environment-based treatments for individuals with AN who exhibit autistic behaviors and individuals with ASD who display disordered eating behaviors or anorexic symptoms.

Causes of death in hospitalized patients with systemic lupus erythematosus: a 10-year multicenter nationwide Chinese cohort

To estimate the mortality and describe the causes of death in a large multicenter cohort of hospitalized patients with SLE in China. This was a retrospective study of a nationwide SLE cohort (10 centers, 29,510 hospitalized patients) from 2005 to 2014 in China. Standardized mortality ratios (SMRs) were calculated for all death and were stratified by sex and age. Chi-square test was used to determine whether the major causes of death vary in age, sex, duration of SLE, disease activity, or medications. Comparison between dead patients and survival controls was used to identify the risk factors for mortality. Logistic regression analysis was used to evaluate the risk factors for mortality. A total of 360 patients died during the study period, accounting for 1.22%. The overall SMR was 2.13 (95% CI 1.96, 2.30), with a particularly high SMR seen in subgroups characterized by younger age. Infection (65.8%) was the most common cause of death, followed by lupus nephritis (48.6%), hematological abnormality (18.1%), neuropsychiatric lupus/NPSLE (15.8%), and interstitial pneumonia (13.1%). Cardiovascular disease and malignancy contributed little to the causes of death. Infection, in particular severe pulmonary infection, emerged as the foremost risk factor for mortality, followed by lupus encephalopathy. However, lupus nephritis and hematological abnormalities occurred more frequently in survival patients. SLE patients at a younger age of diagnosis have a poorer prognosis. Infection dominated the causes of death in recent China. Ethnicity and medications might account for the differences in causes of death compared with western populations.

[Expression of B cell transposition gene 3 in pancreatic ductal adenocarcinoma and its prognostic value]

Objective: To detect the expression of B cell transposition gene 3(BTG3) in pancreatic ductal adenocarcinoma(PDAC), and explore its relationship with postoperative recurrence and metastasis of tumor. Methods: Six self-paired frozen PDAC specimens and 3 normal pancreatic tissues from the Second Hospital of Jiaxing Affiliated to Jiaxing University were collected and the expression of BTG3 was detected by qPCR. Ten normal pancreatic tissues and 52 cases of PDAC tumor and paracarcinomatous tissues from the Second Hospital of Jiaxing Affiliated to Jiaxing University were collected from June 2009 to December 2016. The expression of BTG3 and relationship among BTG3 and clinicopathological characteristics of PDAC and patients' prognosis were detected and analyzed using immunohistochemistry.χ(2) test, Kaplan-Meier method and Cox regression model were used to analyzed the data. Results: The results of qPCR showed that expression level of BTG3 in PDAC (0.63±0.17) was lower significantly than that in paracarcinomatous (0.96±0.04) and normal tissues (1.00)(t=4.673, 5.502; both P<0.05). Immunohistochemistrv showed that BTG3 mainly expressed in the cytoplasm.The high expression rate of BTG3 in PDAC tumor tissues was 25.0%(13/52), which was remarkably lower than that in paracarcinomatous tissues(65.4%) and normal liver tissues(7/10)(χ(2)=17.120 and 5.849, both P<0.05). The low expression of BTG3 in PDAC was correlated with primary tumor, and TNM stage(χ(2)=7.704, P=0.006; U=154.000, P=0.018, respectively). Survival analysis showed that disease free survival rate of patients with low expression of BTG3 was significantly less than that with high expression(χ(2)=192.493, P<0.01). The Cox multivariate analysis demonstrated that low expression of BTG3 was independent risk factors for disease free survival in patients with PDAC after a curative resection(RR=3.366, 95%CI: 1.040-10.889, P=0.043). Conclusion: BTG3 may be involved in the occurence and development of tumor, and its low expression may be associated with poor prognosis in patients with PDAC.

[Oxidative stress and autophagy in SK-N-SH cells induced by manganese chloride or 1-methyl-4-phenylpyridinium: a comparative analysis]

Objective: To investigate the effect of manganese chloride (MnCl(2)) or 1-methyl-4-phenylpyridinium (MPP (+)) on oxidative stress and autophagy in human neuroblastomaSK-N-SH cells and the mechanism of the neurotoxicity of manganese. Methods: SK-N-SH cells were treated with MnCl(2) or MPP(+) at doses of 0.062 5, 0.125, 0.25, 0.5, 1.0, and 2.0 mmol/L for 24 hours, and MTT assay was used to measure cell viability. The cells weretreated with MnCl(2) or MPP(+) at doses of 0.125, 0.25, and 0.5 mmol/L for 24 hours, and flow cytometry was used to measure the content of reactive oxygen species (ROS) in cells, a laser scanning confocal microscope was used to observe autophagosome in cells, and Western blot was used to measure the expression of autophagy-related proteins P62 and LC3-II/LC3-I. Results: Compared with the control group, the 0.0625-2.0 mmol/L MnCl(2) and 0.125-2.0 mmol/L MPP (+) treatment groups had significant reductions in the viability of SK-N-SH cells, and the 0.25-2.0 mmol/L MnCl(2) treatment groups had significantly lower viability than the groups treated with the same doses of MPP(+) (all P<0.05) . Compared with the control group, the 0.125-0.25 mmol/L MnCl(2) and 0.125-0.5 mmol/L MPP(+) treatment groups had significant increases in the content of ROS, and the 0.25-0.5 mmol/L MPP(+) treatment groups had significantly higher content of ROS than the groups treated with the same doses of MnCl(2) (all P<0.05) . Compared with the control group, the 0.25-0.5 mmol/L MnCl(2) andMPP(+) treatment groups had significant increases in autophagy-related proteins LC3-II/LC3-I and significant reductions in P62 expression; the 0.125-0.5 mmol/L MPP(+) treatment groups had significantly higher LC3-II/LC3-I than the groups treated with the same doses of MnCl(2), and the 0.125 and 0.25 mmol/L MPP (+) treatment groups had significantly lower P62 expression than the groups treated with the same doses of MnCl(2) (all P<0.05) . Conclusion: Both MnCl(2) and MPP(+) can induce oxidative stress and autophagy in SK-N-SH cells, and MPP(+) has a significantly greater inductive effect on autophagy of SK-N-SH cells than MnCl(2).

Transcriptome sequencing of sea cucumber (Apostichopus japonicus) and the identification of gene-associated markers

Sea cucumber (Apostichopus japonicus) is an ecologically and economically important species in East and South-East Asia. This project aimed to identify large numbers of gene-associated markers and differentially expressed genes (DEGs) after lipopolysaccharides (LPS) challenge in A. japonicus using high-throughput transcriptome sequencing. A total of 162 million high-quality reads of 174 million raw reads were obtained by deep sequencing using Illumina HiSeq™ 2000 platform. Assembly of these reads generated 94 704 unigenes, with read length ranging from 200 to 16 153 bp (average length of 810 bp). A total of 36 005 were identified as coding sequences (CDSs), 32 479 of which were successfully annotated. Based on the assembly transcriptome, we identified 142 511 high-quality single nucleotide polymorphisms (SNPs). Among them, 33 775, 63 120 and 45 616 were located in sequences without predicted CDS (non-CDSs), CDSs and untranslated regions (UTRs), respectively. These putative SNPs included 82 664 transitions and 59 847 transversions. Totally, 89 375 (59.1%) were distributed in 15 473 known genes. A total of 6417 microsatellites were detected in 5970 unigenes, 3216 of which were annotated and 2481 were successfully subjected for primer design. The numbers of simple sequence repeats (SSRs) identified in non-CDSs, CDSs and UTRs were 2367, 2316 and 1734. These potential SNPs and SSRs are expected to provide abundant resources for genetic, evolutionary and ecological studies in sea cucumber. Transcriptome comparison revealed 1330, 1347 and 1291 DEGs in the coelomocytes of A. japonicus at 4 h, 24 h and 72 h after LPS challenge, respectively. Approximately 58.4% (1802) of total DEGs have been successfully annotated.

Estival distribution of dissolved metal concentrations in Liaodong Bay

The temporal and spatial distributions of Cu, Pb, Zn, and Cd in surface water of the Liaodong Bay were studied based on samples collected at 16 sites in June and August from 2001 to 2005. The temporal distribution showed decreasing trends. The concentrations of dissolved metals in the Liaodong Bay were 4.34, 3.21, 31.54, and 0.995 mug/L for Cu, Pb, Zn, and Cd, respectively. Cu and Pb were scattered near the estuaries, and Zn and Cd were mainly found near the Wuli River. Rivers were the main metals pollution sources in the Bay.

Apoptosis induced by cadmium in human lymphoma U937 cells through Ca2+-calpain and caspase-mitochondria- dependent pathways

Apoptosis induced by cadmium has been shown in many tissues in vivo and in cultured cells in vitro. However, its molecular mechanism is not fully understood. When the human histiocytic lymphoma cell line U937 was treated with cadmium for 12 h, evidence of apoptotic features, including change in nuclear morphology, DNA fragmentation, formation of DNA ladder in agarose gel electrophoresis, and phosphatidylserine externalization, were obtained. Moreover, loss of the mitochondrial membrane potential (Deltapsi(m)) was observed in the cadmium-treated cells and was inhibited by a broad caspase inhibitor (Z-VAD-FMK). Caspase inhibitors suppressed the DNA fragmentation in the order of Z-VAD-FMK > caspase-8 inhibitor > caspase-3 inhibitor. Expression of Bcl-x(L) and Bid decreased significantly in the cadmium-treated cells, although no apparent change in Bcl-2 and Bax expression was found. Tetrakis-(2-pyridylmethyl) ethylendiamine, a cell-permeable heavy metal chelator, partially reversed the increase of fluorescence of Fura-2 in the cadmium-treated cells. In addition, verapamil (70 microm), a voltage-dependent Ca(2+) channel blocker, inhibited the DNA fragmentation induced by cadmium less than 100 microm and decreased the fluorescence of Fura-2. Cadmium up-regulated the expression of type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R) but not type 2 or type 3 IP(3)R. Calpain inhibitors I and II partially prevented DNA fragmentation. No effects of Z-VAD-FMK on the expression of type 1 IP(3)R or of calpain inhibitors on the loss of Deltapsi(m) were observed. These results suggest that cadmium possibly induced apoptosis in U937 cells through two independent pathways, the Ca(2+)-calpain-dependent pathway and the caspase-mitochondria-dependent pathway.

Genotoxicity of wood dust in a human embryonic lung cell line

Wood dust exposure has been found to be an occupational hazard, being linked to an enhanced incidence of various neoplasias. Here we performed an experiment to evaluate the ability of solvent extracts of natural woods to induce chromosome aberrations in respiratory cells in culture. Human embryonic lung cells, MRC-5, grown in Dulbecco's medium were exposed to various concentrations of the dust extracts of pesticide-free (untreated) beech, oak and pine woods. Three concentrations per extract with and without metabolic activation (S9) and 100 metaphase cells per dose were examined for possible structural aberrations. Although no dose-dependent activity could be found with any extract in the presence of S9, most aberrations observed were of the chromatid type caused by oak wood. Dose-dependent chromosomal breaks caused by oak and chromatid breaks caused by both beech and oak were observed in the absence of S9. These data might support the early hypothesis that hard wood dust per se contains some in vivo genotoxic and thus possibly carcinogenic components.

[Evaluation of the bacteriostasis and the acute hemolytic activity in vitro of three sorts of resinifying agent.]

The bacteriostatic test for the anaerobic which had a direct bearing on pulpal-periapical infection and oral common aerobic bacteriosia were performed.The results indicated the bacteriosia ability of three sorts of resinify agent is in sequence:FR109>FR>GR.We found that FR and GR had no acute hemolyzation in the hemolytic test in vitro,but RF109 caused hemolysis.

[Evaluation of endoscopic retrograde cholangiopancreatography in diagnosis of chronic pancreatitis]

155 cases of chronic pancreatitis in PUMC hospital from 1952 to 1990 were investigated. Because endoscopic retrograde cholangiopancreatography (ERCP) and exocrine pancreatic function tests have been used since 1974, the diagnostic rate of chronic pancreatitis during 1974-1990 is 6.6 fold as that during 1952-1974. The pancreatic duct in 97 cases among 105 cases with chronic pancreatitis examined by ERCP was compared with CT and ultrasonography in diagnosis of chronic pancreatitis. The accuracy of diagnosis for ERCP is 84.8%, and is significantly higher than that for CT (56.0%, P < 0.01) and ultrasonography (37.8%, P < 0.001). The detective rate of abnormal pancreatic duct for ERCP is 91.4%, and is also significantly higher than that for CT (80.0%) and ultrasonography (79.7%, P < 0.05). These data indicated that the clinical features of chronic pancreatitis in China is more related to biliary diseases, rather than alcoholism. BT-PABA test and ultrasonography are valuable screen examinations, and ERCP is credible important examination in diagnosis of chronic pancreatitis.

Structural analysis of CGRP receptors on gastric smooth muscle and pancreatic acinar cells

Calcitonin gene-related peptide (CGRP) immunoreactivity is widely distributed in the central nervous system and gastrointestinal (GI) tract, and specific receptors have been described on many GI tissues. In the present study, we compared CGRP receptors on gastric smooth muscle cells with those on pancreatic acini from guinea pig with the use of chemical cross-linking techniques combined with various enzymatic digestions. 125I-labeled rat CGRP-I demonstrated temperature-dependent saturable binding to both acinar and gastric smooth muscle cell membranes. After binding, membranes were incubated with 1 mM disuccinimidyl suberate (DSS), solubilized with sodium dodecyl sulfate (SDS), and subjected to SDS-polyacrylamide gel electrophoresis. Cross-linked radioactivity was analyzed by autoradiography. A single broad radioactive band [molecular weight (M(r)) 57,000] was seen on cell membranes from both tissues and after cross-linking to intact cells. These bands were not altered by addition of dithiothreitol. This radioactive band was not detected without DSS present or with addition of 10 microM rCGRP-I. rCGRP-I inhibited cross-linking with half-maximal inhibition of 32 nM with membranes from both tissues, and there was a close correlation between its ability to inhibit binding and to inhibit cross-linking. Cross-linking was not inhibited by non-CGRP related peptides. With membranes from both tissues, N-glycanase digestion increased the mobility of the original band. Neuraminidase digestion only slightly increased the mobility of the original band; however, the subsequent addition of O-glycanase showed no additional effect on both membranes. Endoglycosidase H digestion had no effect in either tissue. The present results demonstrate that on both tissues the cell membrane receptor for CGRP is an N-linked sialoglycoprotein. The apparent M(r) of this sialoglycoprotein is 57,000, and this polypeptide does not contain disulfide-linked subunits or O-linked carbohydrates.

Antimutagenic and antitumorigenic activities of nordihydroguaiaretic acid

Nordihydroguaiaretic acid (NDGA), which occurs in the resinous exudates of many plants is used as an antioxidant in fats and oils. In this study we show that NDGA inhibited the mutagenicity of methyl methanesulfonate, benzo[a]pyrene (BP), 2-aminofluorene, and aflatoxin B1 in Salmonella typhimurium strain TA100 or TA98 in the absence and presence of rat hepatic microsomal activation system. The addition of NDGA during and after nitrosation of methylurea (MU) resulted in a dose-dependent inhibition of mutagenicity induced by nitrosation products of MU. In a two-stage skin tumorigenesis protocol using 7,12-dimethylbenz[a]anthracene (DMBA) as the initiating agent followed by twice weekly applications of 12-O-tetradecanoylphorbol-13-acetate (TPA) as tumor promoter, pretreatment of animals with NDGA prior to DMBA application, afforded significant protection against skin tumorigenicity in female SENCAR mice. In additional studies, skin application of NDGA also inhibited the binding of topically applied [3H]BP and [3H]DMBA to epidermal DNA. When assessed in the anti-tumor promotion protocol, pretreatment of animals with NDGA before each application of TPA in DMBA-initiated mouse skin, resulted in 72% decrease in the total number of tumors when compared to non-NDGA pretreated animals. The possible mechanism(s) of the antimutagenic and anti-tumorigenic activities may be due to the multiple effects of NDGA as inhibitor of the carcinogen metabolism and DNA-adduct formation, scavenger of carcinogen free radicals, and as inhibitor of TPA-induced ornithine decarboxylase activity.

Inhibition of mutagenicity in Salmonella typhimurium and skin tumor initiating and tumor promoting activities in SENCAR mice by glycyrrhetinic acid: comparison of 18 alpha- and 18 beta-stereoisomers

Licorice has been used as medicine and as sweetening agent in food products. The major water-soluble constituent of licorice is glycyrrhizin (GL), an oleanane triterpenoide, which is known to be partly hydrolyzed by glucuronidase to its aglycone glycyrrhetinic acid (GA) which exists in 18 alpha (alpha-GA) and 18 beta (beta-GA) stereoisomeric forms. In this study alpha-GA and beta-GA were found to inhibit the mutagenicity of benzo[a]pyrene (B[a]P), 2-aminofluorene and aflatoxin B1 in Salmonella typhimurium TA98 and TA100. beta-GA was more effective than alpha-GA as an antimutagen. In the two-stage skin tumorigenesis protocol using 7,12-dimethylbenz[a]anthracene (DMBA) as the tumor initiating agent followed by twice weekly applications of 12-O-tetradecanoylphorbol-13-acetate as tumor promoter, pretreatment of SENCAR mice with alpha-GA or beta-GA resulted in significant protection against tumor initiation as well as tumor promotion. As an anti-tumor initiating agent, beta-GA was found to be more effective than alpha-GA. Similarly, topical application of beta-GA was found to be more effective than alpha-GA in inhibiting the binding of both [3H]B[a]P and [3H]DMBA to epidermal DNA. However, as an anti-tumor promoter, alpha-GA and beta-GA showed comparable effects. Our results suggest that both alpha-GA and beta-GA possess substantial anti-skin tumor initiating and anti-skin tumor promoting activities.

Activities of calcitonin gene-related peptide (CGRP) and related peptides at the CGRP receptor

In guinea pig pancreatic acini rat calcitonin gene-related peptide (CGRP) increased amylase release 2-fold, salmon calcitonin had an efficacy of only 44% of that of CGRP and [Tyr0]CGRP(28-37) and human calcitonin had no actions. [Tyr0]CGRP(28-37), but not human calcitonin, antagonized the actions of CGRP in pancreatic acini with an IC50 of 3 microM. [Tyr0]CGRP(28-37) produced a parallel rightward shift in the dose-response curve for CGRP-stimulated amylase secretion. The inhibition was specific for CGRP and was reversible. Studies with 125I-CGRP demonstrated that CGRP, salmon calcitonin and [Tyr0]CGRP, but not human calcitonin, interacted with CGRP receptors on pancreatic acini. These results indicate that various CGRP-related peptides demonstrate different relationships between their abilities to occupy the CGRP receptor and to affect biologic activity, with CGRP itself being a full agonist, salmon calcitonin a partial agonist, [Tyr0]CGRP(28-37) a competitive antagonist, and human calcitonin having no actions.

Antimutagenic activity of green tea polyphenols

For centuries green tea has been a widely consumed beverage throughout the world. It is known to contain a number of pharmacologically active compounds. In this study water extracts of green tea (WEGT) and their major constituents, green tea polyphenols (GTP), were examined for antimutagenic activity. WEGT and GTP were found to significantly inhibit the reverse mutation induced by benzo[alpha]pyrene (BP), aflatoxin B1 (AFB1), 2-aminofluorene, and methanol extracts of coal tar pitch in Salmonella typhimurium TA100 and/or TA98 in the presence of a rat-liver microsomal activation system. GTP also inhibited gene forward mutation in V79 cells treated with AFB1 and BP, and also decreased the frequency of sister-chromatid exchanges and chromosomal aberrations in V79 cells treated with AFB1. The addition of GTP during and after nitrosation of methylurea resulted in a dose-dependent inhibition of mutagenicity. Studies to define the mechanism of the antimutagenic activity of GTP suggest that it may affect carcinogen metabolism, DNA adduct formation, the interaction of ultimate carcinogen or the scavenging of free radicals.

Interaction of peptides related to VIP and secretin with guinea pig pancreatic acini

The abilities of human and rat growth hormone-releasing factors (hGHRF, rGHRF), peptide histidine isoleucine or methionine (PHI, PHM) and the Gila monster venom peptides (helospectin I, helospectin II, and helodermin) to interact with guinea pig pancreatic acini were characterized and compared with vasoactive intestinal peptide (VIP) and secretin. Each peptide caused a sevenfold stimulation of amylase release, and the relative potencies were: VIP greater than helospectin I = helospectin II = helodermin = rGHRF greater than PHI = PHM greater than hGHRF greater than secretin. Each peptide inhibited 125I-labeled VIP binding, and the relative potencies agreed closely with those for stimulating enzyme secretion. Each peptide inhibited 125I-labeled secretin binding with the potencies: secretin greater than helospectin I = helospectin II = helodermin greater than rGHRF = PHI = VIP greater than PHM greater than hGHRF. Each peptide caused a 78-fold increase in adenosine 3',5'-cyclic monophosphate cAMP. VIP or rGHRF and PHI or PHM demonstrated high and low selectivity, respectively, for VIP receptors, secretin high selectivity for the secretin receptor, and helospectin I or II and helodermin a relatively high affinity for both VIP and secretin receptors. Correlation of the ability of each peptide to increase cAMP or amylase release and inhibit binding of 125I-VIP or 125I-secretin suggested all the actions of these peptides could be explained by the occupation of VIP or secretin receptors. To investigate this further, 125I-labeled helodermin was prepared, and binding was saturable, specific, and could be accounted for by the binding to VIP or secretin receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of receptors for calcitonin gene-related peptide on gastric smooth muscle cells

Rat calcitonin gene-related peptide (rat CGRP) and related peptides did not cause contraction of gastric smooth muscle cells; however, preincubation with rat CGRP or human CGRP inhibited smooth muscle contraction caused by carbachol. Rat CGRP and human CGRP were equipotent in opposing contraction with a half-maximal effect produced by 0.1 nM, but rat calcitonin-adjacent peptide (rat CAP) and human calcitonin had no effect. Rat CGRP caused an increase in cellular adenosine 3',5'-cyclic monophosphate (cAMP) of 60%, which was augmented to 155% with 1 mM isobutyl methylxanthine (IBMX). IBMX did not influence the sensitivity of the muscle cells to rat CGRP to increase cAMP, the half maximal effect being produced by 0.4 nM in the presence or absence of IBMX. Rat CGRP and human CGRP were equipotent for stimulating cAMP, but rat CAP and human calcitonin had no effect. Binding of 125I-CGRP was temperature dependent, saturable, reversible, and specific. Rat CGRP and human CGRP were equipotent at inhibiting binding of 125I-CGRP and rat CAP, and human calcitonin did not inhibit binding. For rat CGRP and human CGRP, the dose-response curves for binding of 125I-CGRP were broad, and both peptides accelerated the rate of dissociation of bound 125I-CGRP. Computer analysis of dose-response curves demonstrated two classes of binding sites for CGRP, one with a high affinity (Kd 3 nM) and another with low affinity (Kd 3,700 nM). Our results indicate that CGRP interacts with previously undescribed receptors on gastric smooth muscle cells to increase cellular cAMP and inhibit contraction.

Characterization of gastrin receptors on guinea pig pancreatic acini

Recent studies have demonstrated gastrin receptors in some pancreatic tumors and that gastrin is a potent stimulant of pancreatic Na+-H+ exchange. In the present study we used 125I-labeled gastrin (125I-gastrin) to characterize gastrin receptors on guinea pig pancreatic acini. Binding of 125I-gastrin was temperature dependent, saturable, and specific for gastrin-related peptides. Analysis demonstrated a single class of receptors with high affinity for gastrin (Kd = 1.5 nM) and a binding capacity of 1 fmol/mg protein. Binding of 125I-gastrin was inhibited with the following relative potencies (Kd): cholecystokinin octapeptide (CCK-8) (0.35 nM) greater than gastrin-17-I = gastrin-34-I (1.5 nM) greater than pentagastrin (7 nM) greater than desulfated [des(SO3)]CCK-8 (28 nM) greater than CCK-4 (508 nM) and by the receptor antagonists CBZ-CCK-27-32-NH2 (3.5 microM) greater than proglumide analogue 10 (30 microM) greater than asperlicin (265 microM) greater than Bt2-guanosine 3',5'-cyclic monophosphate (828 micron). In contrast, for both stimulation of enzyme secretion and inhibition of binding of 125I-CCK-8 the relative potencies were CCK-8 much greater than des(SO3)CCK-8 greater than gastrin-17-I = gastrin-34-I greater than pentagastrin greater than CCK-4. For each receptor antagonist the dose-inhibition curve for gastrin-stimulated amylase release was superimpossible with that for CCK-8-stimulated amylase release. Gastrin-17-I at concentrations less than 0.1 microM did not potentiate carbachol or vasoactive intestinal peptide-stimulated amylase secretion and did not affect basal or stimulated adenosine 3',5'-cyclic monophosphate or 45Ca outflux.(ABSTRACT TRUNCATED AT 250 WORDS)

Receptors for vasoactive intestinal peptide and secretin on guinea pig pancreatic acini

We investigated the abilities of VIP and secretin to occupy receptors and to increase cellular cyclic AMP using dispersed acini from guinea pig pancreas. The dose-inhibition curve for inhibition of binding of 125I-VIP by VIP was broad with detectable inhibition at 0.1 nM VIP, half-maximal inhibition at 2 nM VIP and complete inhibition at 10 microM VIP. Secretin also inhibited binding of 125I-VIP was compatible with two VIP-preferring receptors with one class having a high affinity for VIP (Kd 1.1 nM) and a low affinity for secretin (Kd 5 microM) and the other class having an intermediate affinity for VIP (Kd 470 nM). The dose inhibition curve for inhibition of binding of 125I-secretin by secretin was not broad. Half-maximal inhibition occurred with 7 nM secretin or with 10 microM VIP. Computer analysis was compatible with a single secretin-preferring receptor with a high affinity for secretin (Kd 7 nM) and a low affinity for VIP (Kd 5.9 microM). Comparison of the ability of VIP to increase cyclic AMP with or without the secretin-receptor antagonist, secretin-5-27, demonstrated only occupation of the high affinity VIP-preferring or high affinity secretin-preferring receptors increase cyclic AMP. Our results demonstrate that, in contrast to previous reports, guinea pig pancreatic acini possess 3 classes of receptors that interact with VIP and secretin. The low affinity receptor seen with 125I-VIP is not the same as the secretin-preferring receptor and does not increase cellular cyclic AMP.

Characterization of receptors for VIP on pancreatic acinar cell plasma membranes using covalent cross-linking

Vasoactive intestinal peptide (VIP) receptors on guinea pig pancreatic acini differ from those on all other tissues in containing a high-affinity VIP receptor and a low-affinity VIP receptor that has a high affinity for secretin. To characterize the molecular components of these receptors, 125I-VIP was covalently cross-linked to these receptors by four different cross-linking agents: disuccinimidyl suberate, ethylene glycol bis (succinimidyl succinate), dithiobis (succinimidylpropionate), and m-maleimidobenzoyl N-hydroxysuccinimide ester. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated a single major polypeptide band of Mr 45,000 and a minor polypeptide band of Mr 30,000 were cross-linked to 125I-VIP. Covalent cross-linking only occurred when a cross-linking agent was added, was inhibited by GTP, was inhibited by VIP receptor agonists or antagonists that interact with VIP receptors, and not by other pancreatic secretagogues that interact with different receptors. For inhibiting both cross-linking and binding of 125I-VIP to the major polypeptide Mr 45,000 and the minor polypeptide Mr 30,000 components, the relative potencies were VIP greater than helodermin greater than rat growth hormone releasing factor greater than peptide histidine isoleucine greater than secretin. The apparent molecular weight of the cross-linked polypeptides were unchanged by dithiothreitol. Thus the high-affinity VIP receptor on pancreatic acinar cell membranes consists of a single major polypeptide of Mr 45,000, and this polypeptide is not a subunit of a larger disulfide-linked structure. Furthermore, either the low-affinity VIP/secretin-preferring receptor was not covalently cross-linked under the experimental conditions or it consists of a major polypeptide with the same molecular weight as the high-affinity VIP receptor.

Structural features of various proglumide-related cholecystokinin receptor antagonists

Thirteen proglumide derivatives that varied in the length of the di-n-alkyl group and in the substitutions on the benzoyl moiety were tested for their ability to interact with guinea pig pancreatic cholecystokinin (CCK) receptors. Each derivative was more potent than proglumide. There was a close correlation between their abilities to inhibit CCK-stimulated amylase release and to inhibit binding of 125I-CCK. For the di-n-alkyl derivatives the relative potency was n-pentyl greater than n-hexyl greater than n-butyl greater than n-propyl. For the benzoyl moiety, adding two electron-withdrawing groups increased potency more than adding a single electron-withdrawing group or adding electron-donating groups. The 3,4-dichloro-di-n-pentyl derivative of proglumide was 1,300 times more potent than proglumide, and its action was specific, competitive, and it functioned as a CCK receptor antagonist in rat, mouse, and guinea pig pancreas. For all proglumide derivatives there was a good correlation (r = 0.84, P less than 0.001) between their abilities to inhibit CCK-stimulated amylase release and that previously reported for their abilities to inhibit CCK-induced gallbladder contraction. However, certain proglumide derivatives had a much higher affinity for the pancreatic CCK receptor than for the CCK receptor mediating gallbladder contraction. For other proglumide derivatives the pattern was reversed. These results demonstrate that both the di-n-alkyl group and the substitution on the benzoyl moiety of proglumide are equally important determinants of affinity and that derivatives such as the di-n-pentyl 3,4-dichloro analogue can be produced that are 1,300 times more potent than proglumide.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of action of calcitonin gene-related peptide in stimulating pancreatic enzyme secretion

In guinea pig pancreatic acini rat calcitonin gene-related peptide (CGRP) caused an eightfold increase in amylase release with various phosphodiesterase inhibitors present. Rat CGRP and rat [Tyro]CGRP caused half-maximal effect at 2 nM, and were threefold more potent than human CGRP. CGRP-stimulated amylase release was not inhibited by VIP-(10-28) or secretin-(5-27). CGRP stimulated cAMP and was augmented by phosphodiesterase inhibitors with the order of sensitivity being Ro-20-1724 greater than isobutylmethylxanthine greater than theophylline. CGRP did not increase 45Ca outflux or effect of 125I-VIP binding. CGRP specifically inhibited 125I-CGRP binding. The dose-response curves were broad and each peptide accelerated dissociation of bound 125I-CGRP. Computer analysis demonstrated two classes of CGRP-binding sites. Occupation of a high-affinity class (Kd 20 nM) correlated with stimulation of enzyme secretion and cAMP, and occupation of the low-affinity class (Kd 1 microM) correlated with accelerated dissociation. These studies demonstrate that CGRP interacts with specific pancreatic receptors, CGRP-stimulated cAMP is in a different compartment from that stimulated by other secretagogues, and CGRP differs from other agents that increase cAMP and amylase release in the relationship among receptor occupation, cAMP generation, and enzyme secretion.