Replication Study of the Association of GAS6 and PROS1 Polymorphisms with Behçet's Disease in a Japanese Population

PURPOSE

To investigate whether polymorphisms of GAS6 and PROS1, which each encode protein ligands for a family of tyrosine kinase receptors, are associated with Behçet's disease (BD) in a Japanese population.

METHODS

We recruited 734 Japanese patients with BD and 1789 Japanese healthy controls. In all participants, we genotyped two single-nucleotide polymorphisms (SNPs) reportedly associated with BD: rs9577873 in GAS6 and rs4857037 in PROS1.

RESULTS

We found that GAS6 rs9577873 was not significantly associated with BD. In contrast, PROS1 rs4857037, specifically the A allele, was associated with increased risk for BD. The A allele was also significantly associated with BD under additive and recessive genetic models. Expression analysis revealed that this allele was significantly associated with increased PROS1 expression.

CONCLUSIONS

Our findings suggest that increased PROS1 expression related to the A risk allele of rs4857037 affects tyrosine kinase receptor signaling, contributing to the development of BD.

Platelet volume indices correlate to severity of heart failure and have prognostic value for both cardiac and thrombotic events in patients with congenital heart disease

Introduction

Patients with heart failure are reported to have activated platelets leading to thrombotic events. Consequently, immature giant platelets are produced, and platelet distribution width (PDW) and mean platelet volume (MPV) increase. These platelet indices are easily, reasonably, and safely available by routine blood test and recently have been proposed as potential markers of cardiac events. However, little is known about the usefulness of platelet indices in patients with congenital heart disease (CHD).

Purpose

To test whether the hypothesis that PDW and MPV correlate to the severity of heart failure and have prognostic value in both future heart failure-related admission and thrombosis formation in patients with CHD.

Methods

We performed a retrospective, single-centre study that included 400 patients with CHD (median age, 34 years [range: 12–76]; 49% males; 35% single ventricular morphology), who were admitted in our institute between April 2014 and June 2017. We reviewed patients' medical records to assess their clinical information including medical history, blood sample data, and echocardiologic parameters. At first, we assessed the correlation between platelet indices and patients' clinical parameters. Next, we compared platelet indices before and after treatment for heart failure. Finally, using logistic regression and Kaplan-Meier analyses, we assessed prognostic factors of future heart failure-related admission and thrombosis formation.

Results

In multivariate analysis, a significant correlation was found between PDW and logBNP (brain natriuretic peptide) (p<0.001), haemoglobin (p=0.01), D-dimer (p=0.019), Fontan operation (p<0.001) and male sex (p<0.001); as well as between MPV and logBNP (p<0.001), D-dimer (p<0.001) and Fontan operation (p=0.002). Throughout treatment of heart failure, significant reduction was found both in PDW (average value before treatment = 14.2, after treatment = 13.2, p=0.002) and MPV (before = 11.2, after = 10.8, p=0.004). In multivariate logistic regression analysis, predictors of future heart failure-related admissions were PDW (hazard ratio [HR]: 1.365; 95% confidence interval [CI]: 1.005–1.768), MPV (HR: 1.472; 95% CI: 1.055–2.052), age (HR: 1.063; 95% CI: 1.010–1.119), and SpO2 under 85% (HR: 5.089; 95% CI: 1.350–19.18). Using the same analysis, predictors of thrombotic formation were PDW (HR: 1.998; 95% CI: 1.461–2.630), MPV (HR: 1.792; 95% CI: 1.155–2.781), logBNP (HR: 1.196, 95% CI: 1.085–1.320), D-dimer (HR: 1.024; 95% CI: 1.007–1.042) and male sex (HR: 3.071; 95% CI: 1.079–8.737). In addition, during median follow-up of 28 months, the Kaplan-Meier analysis showed an improvement in both heart failure and thrombosis-free survival in the low PDW, as well as the low MPV group.

Conclusion

Platelet volume indices correlate to severity of heart failure and have prognostic value for both cardiac and thrombotic events in patients with congenital heart disease.

Funding Acknowledgement

Type of funding source: None

Usefulness of Combined Measurement of Serum Soluble IL-2R and Angiotensin-Converting Enzyme in the Detection of Uveitis Associated with Japanese Sarcoidosis

Purpose

Angiotensin-converting enzyme (ACE) is conventionally used as a biomarker in the diagnosis of uveitis associated with sarcoidosis, but its sensitivity is relatively low. In this study, we investigated whether serum soluble interleukin-2 receptor (sIL-2R) is also useful as a diagnostic marker, in addition to ACE, in the detection of uveitis associated with sarcoidosis.

Patients and Methods

Data were analyzed from 126 patients with uveitis (52 sarcoidosis and 74 non-sarcoid uveitis) and 12 with primary intraocular lymphoma (PIOL) who had their serum sIL-2R and ACE levels measured.

Results

Serum sIL-2R level was elevated in 69.2% of patients with sarcoid uveitis, 5.4% of those with non-sarcoid uveitis, and 16.7% of those with PIOL. The sensitivity and specificity of an elevated sIL-2R level for the detection of sarcoidosis were 69.2% and 93.0%, respectively. In contrast, serum ACE levels were elevated only in patients with sarcoid uveitis, with a sensitivity of 44.2% and specificity of 100%. Furthermore, serum sIL-2R and/or ACE level was elevated in 75.0% of patients with sarcoid uveitis, which is higher than those who had elevated serum ACE level only (44.2%, P = 0.0025). The sensitivity and specificity of elevated sIL-2R and/or ACE in detecting sarcoid uveitis were 75.0% and 93.0%, respectively. The PPV was 0.87, and the NPV was 0.86.

Conclusion

Compared with the sensitivity of serum ACE levels alone, combined measurement of both serum sIL-2R and ACE levels improves sensitivity in the detection of uveitis associated with sarcoidosis. Nevertheless, serum ACE alone remains useful thanks to its high specificity in the differentiation of uveitis patients, with sarcoidosis from those without sarcoidosis.

Genetic control of CCL24, POR, and IL23R contributes to the pathogenesis of sarcoidosis

Sarcoidosis is a genetically complex systemic inflammatory disease that affects multiple organs. We present a GWAS of a Japanese cohort (700 sarcoidosis cases and 886 controls) with replication in independent samples from Japan (931 cases and 1,042 controls) and the Czech Republic (265 cases and 264 controls). We identified three loci outside the HLA complex, CCL24, STYXL1-SRRM3, and C1orf141-IL23R, which showed genome-wide significant associations (P < 5.0 × 10⁻⁸) with sarcoidosis; CCL24 and STYXL1-SRRM3 were novel. The disease-risk alleles in CCL24 and IL23R were associated with reduced CCL24 and IL23R expression, respectively. The disease-risk allele in STYXL1-SRRM3 was associated with elevated POR expression. These results suggest that genetic control of CCL24, POR, and IL23R expression contribute to the pathogenesis of sarcoidosis. We speculate that the CCL24 risk allele might be involved in a polarized Th1 response in sarcoidosis, and that POR and IL23R risk alleles may lead to diminished host defense against sarcoidosis pathogens.

Akira Meguro et al. report a genome-wide association study for sarcoidosis—a systemic inflammatory disease—in the Japanese population. They identify 3 non-HLA loci with genome-wide significance, 2 of which have not been previously associated with sarcoidosis in any population.

HLA-A26 is a risk factor for Behçet's disease ocular lesions

BACKGROUND

How HLA-A26 modulates Behçet's disease (BD) ocular lesions such as iridocyclitis and retinochorioiditis has not been scrutinized.

METHODS

Ministry of Health, Labour and Welfare of Japan provided us a database of BD patients who were registered from 2003 to 2014. We selected patients who satisfied International Criteria for BD and whose data for HLA-A26 was available.

RESULTS

Eligible 557 patients consisting of 238 men (42.7%) and 319 women (57.3%), whose median age was 38 years old (interquartile range 29-47) were analyzed. Prevalence of general ocular lesions, iridocyclitis, retinochorioiditis, and chronic lesions were 43.1%, 30.7%, 34.1%, and 17.4%, respectively. The prevalence of ocular lesions was higher among HLA-A26 carriers compared to that among HLA-A26 non-carriers with odds ratio (OR) of 2.5 (95% confidence interval (95% CI) 1.8-3.5, p < .001) for general ocular lesions, OR of 2.5 (95% CI 1.7-3.6, p < .001) for iridocyclitis, OR of 2.8 (95% CI 1.9-4.0, p < .001) for retinochorioiditis, and OR of 2.7 (95% CI 1.7-4.3, p < .001) for 'chronic ocular lesion following iridocyclitis or retinochorioiditis'. The HLA-A26 had a similar impact on ocular lesions between HLA-B51 positive and negative cases (Breslow-Day test, p > .05). However, the HLA-A26 had a larger impact on iridocyclitis for men compared to women (Breslow-Day test, p = .040). The male HLA-A26 carriers had higher risk of iridocyclitis with OR of 3.4 (95% CI 2.0-5.9, p < .001), while the OR for women was 1.5 (95% CI 0.9-2.6, p = .146).

CONCLUSION

HLA-A26 carriers had higher risk for iridocyclitis and retinochorioiditis. However, the impact was more prominent for men.

The influence of HLA-B51 on clinical manifestations among Japanese patients with Behçet's disease: A nationwide survey

Objectives: To scrutinize the influence of HLA-B51 to each clinical manifestation of patients with Behçet's disease (BD) using a database of the Ministry of Health, Labour and Welfare of Japan.Methods: The database of newly registered patients with BD was obtained from the Japanese Ministry of Health, Labour and Welfare. Patients who met International Criteria for Behçet's Disease (ICBD) and had data for HLA-B51 were selected and analyzed.Results: Among the 3044 analyzable cases, 1334 (43.8%) were men and 1710 (56.2%) were women; the median age was 38 years (IQR 29-48). HLA-B51 was positive for 1334 (44.5%). Prevalence of selected manifestations was 98.5% for oral ulceration, 85.5% for skin lesion, 42.1% for ocular lesion, 69.1% for genital ulceration, and 29.0% for gastrointestinal symptom. HLA-B51-positive patients had higher risk for ocular lesion (OR 1.59, 95%CI: 1.37-1.84; p < .001) and lower risk for genital ulceration (OR 0.72, 95%CI: 0.62-0.84; p < .001) and gastrointestinal symptom (OR 0.65, 95%CI: 0.55-0.77; p < .001). No significant difference was observed for other organ involvement; oral ulceration, skin lesion, positive pathergy test, arthritis, epididymitis, vascular lesion, or neurological manifestation. Subgroup analyses revealed that HLA-B51 was not related to genital ulceration in the cases with an ICBD score of 6 or higher and that HLA-B51 tended to more largely affect the risk of three manifestations for men compared to that for women.Conclusion: HLA-B51 positive is a risk factor for ocular lesion and vice versa for genital ulceration and gastrointestinal symptoms in patients with Japanese BD.

The ocular involvement did not accompany with the genital ulcer or the gastrointestinal symptoms at the early stage of Behçet's disease

OBJECTIVES

This study aimed to identify patients with high-probability of ocular involvement of Behçet's disease (BD).

METHODS

The Japanese Ministry of Health, Labour and Welfare provided dataset of ongoing nationwide BD registration project. A patient who had confirmed BD and who was suspected to have BD was registered. We mainly analyzed newly registered patients who had the data for all demographic and diagnostic parameters regardless of fulfilment of any diagnostic criteria.

RESULTS

Among 3213 patients with confirmed or possible BD, 1382 (43.0%) were men and 1831 (57.0%) were women with a median age of 38 years (interquartile range (IQR) 30-49 years). The median duration between onset and registration was 0 year (IQR 0-3). A binomial multivariable logistic regression analysis revealed that being female (odds ratio (OR) 0.63, 95% confidence interval (CI) 0.53-0.75, p < .001), duration since onset (OR 1.33 per 10 years, 95% CI 1.18-1.51, p < .001), genital ulceration (OR 0.28, 95% CI 0.23-0.34, p < .001), and gastrointestinal symptoms (OR 0.36, 95% CI 0.30-0.44, p < .001) were related to the ocular lesion. Analyses based on data of 2800 patients who satisfied International criteria of BD, age-, sex-, duration-based subgroup analyses, analyses targeting iridocyclitis and retino-uveitis, and analysis including patients with missing data confirmed that the four factors were associated with the probability of eye involvement.

CONCLUSION

The ocular involvement did not accompany with genital ulcer or gastrointestinal symptoms at the early stage of BD.

Distinct clinical features between acute and chronic progressive parenchymal neuro-Behçet disease: meta-analysis

Neuro-Behçet’s disease (NBD) is subcategorized into parenchymal-NBD (P-NBD) and non-parenchymal-NBD types. Recently, P-NBD has been further subdivided into acute P-NBD (A-P-NBD) and chronic progressive P-NBD (CP-P-NBD). Although an increasing number of studies have reported the various clinical features of A-P-NBD and CP-P-NBD over the last two decades, there was a considerable inconsistency. Two investigators systematically searched four electrical databases to detect studies that provided sufficient data to assess the specific characteristics of A-P-NBD and CP-P-NBD. All meta-analysis was carried out by employing the random-model generic inverse variance method. We included 11 reports consisted of 184 A-P-NBD patients and 114 CP-P-NBD patients. While fever (42% for A-P-NBD, 5% for CP-P-NBD, p < 0.001, I² = 93%) was more frequently observed in A-P-NBD cases; sphincter disturbances (9%, 34%, P = 0.005, I² = 87%), ataxia (16%, 57%, P < 0.001, I² = 92%), dementia (7%, 61%, P < 0.001, I² = 97%), confusion (5%, 18%, P = 0.04, I² = 76%), brain stem atrophy on MRI (4%, 75%, P < 0.001, I² = 98%), and abnormal MRI findings in cerebellum (7%, 54%, P = 0.02, I² = 81%) were more common in CP-P-NBD. Cerebrospinal fluid cell count (94/mm³, 11/mm³, P = 0.009, I² = 85%) was higher in A-P-NBD cases. We demonstrated that A-P-NBD and CP-P-NBD had clearly different clinical features and believe that these data will help future studies investigating P-NBD.

The expression patterns of Pax7 in satellite cells during overload-induced rat adult skeletal muscle hypertrophy

AIM

Activated satellite cells (SCs) have the ability to reacquire a quiescent, undifferentiated state. Pax7 plays a crucial role in allowing activated SCs to undergo self-renewal. Because the increase in the SC population is induced during overload-induced skeletal muscle hypertrophy, it is possible that Pax7-regulated SC self-renewal is involved in the modulation of the SC population during the functional overload of skeletal muscles. However, the characteristics of the expression patterns of Pax7 in SCs during the functional overload of adult skeletal muscles are poorly understood.

METHODS

Using immunohistochemical approaches, we examined the temporal and spatial expression patterns of Pax7 expressed in SCs during the functional overloading of rat skeletal muscles.

RESULTS

The time course of Pax7 expression in SCs was similar to that of the expression of the differentiation regulatory factor myogenin during the early stage of functional overload. However, the percentage of SCs that expressed Pax7 was markedly higher than that of the SCs that expressed myogenin. Coexpression of Pax7 and myogenin was not detected in SCs. In addition, the expression of cyclin-dependent kinase inhibitor p21, which regulates cell cycle arrest and differentiation, was not detected in Pax7-positive SCs.

CONCLUSION

These results suggest that Pax7-regulated self-renewal of SCs may be induced during the early stage of functional overload and may contribute to modulating the SC population in hypertrophied muscles. Furthermore, it was suggested that the numbers of SCs which underwent self-renewal may be higher than that of SCs which were provided as the additional myonuclei for hypertrophying myofibres.

Alterations of M-cadherin, neural cell adhesion molecule and beta-catenin expression in satellite cells during overload-induced skeletal muscle hypertrophy

AIM

Neural cell adhesion molecule (NCAM) and M-cadherin are cell adhesion molecules expressed on the surface of skeletal muscle satellite cell (SC). During myogenic morphogenesis, M-cadherin participates in mediating terminal differentiation and fusion of myoblasts by forming a complex with beta-catenin and that NCAM contributes to myotube formation by fusion of myoblasts. Hypertrophy and hyperplasia of functionally overloaded skeletal muscle results from the fusion with SCs into the existing myofibres or new myofibre formation by SC-SC fusion. However, the alterations of NCAM, M-cadherin and beta-catenin expressions in SCs in response to functional overload have not been investigated.

METHODS

Using immunohistochemical approaches, we examined the temporal and spatial expression patterns of these factors expressed in SCs during the functional overload of skeletal muscles.

RESULTS

Myofibres with SCs showing NCAM+/M-cadherin-, NCAM+/M-cadherin+ or NCAM-/M-cadherin+ were detected in overloaded muscles. The percentage changes of myofibres with SCs showing NCAM+/M-cadherin-, NCAM+/M-cadherin+ or NCAM-/M-cadherin+ were elevated in day-3 post-overloaded muscles, and then only the percentage changes of myofibres with SCs showing NCAM-/M-cadherin+ were significantly increased in day-7 post-overload muscles (P < 0.05). Both beta-catenin and M-cadherin were co-localized throughout quiescent, proliferation and differentiation stages of SCs.

CONCLUSION

These results suggested that the expressions of NCAM, M-cadherin and beta-catenin in SCs may be controlled by distinct regulatory mechanisms during functional overload, and that interactions among NCAM, M-cadherin and beta-catenin in SCs may play important roles to contribute to overload-induced muscle hypertrophy via fusion with each other or into the existing myofibres of SCs.

Localization of MyoD, myogenin and cell cycle regulatory factors in hypertrophying rat skeletal muscles

AIM

MyoD, myogenin, proliferating cell nuclear antigen (PCNA) and cyclin-dependent kinase inhibitor p21 (p21) proteins are key molecules in inducing the growth of myogenic cells in vitro. However, it has not been determined which cell types express these factors in hypertrophying skeletal muscles in vivo.

METHODS

Using immunohistochemical techniques, we examined the spatial and temporal expression patterns of MyoD, myogenin, PCNA and p21 proteins in functionally overloaded rat plantaris muscles induced by ablation of the soleus and gastrocnemius muscles.

RESULTS

MyoD and myogenin were detected in myonuclei located inside the dystrophin-positive plasma membrane of myofibres, m-cadherin-positive satellite cell nuclei and nuclei located in the interstitial spaces between myofibres on days 1, 3, 5 and 7 post-surgery. Entry of satellite cells into the cell cycle was indicated by the expression of PCNA on day 3 post-surgery, and withdrawal from the cell cycle was observed by the expression of p21 in satellite cell nuclei on day 5 post-surgery. However, the expression of both PCNA and p21 in satellite cell nuclei disappeared on day 7 post-surgery.

CONCLUSION

These results indicate that proliferated satellite cell-derived myoblasts and undefined myogenic cells located in the interstitial spaces may contribute to an increase in myonuclear number and/or hyperplasia. Furthermore, we provide evidence that all of myonuclei, satellite cells and undefined myogenic cells express both MyoD and myogenin proteins. These results suggest that continual expression of MyoD and myogenin proteins in these cells is an essential molecular event which induces the successful hypertrophy of skeletal muscles.

Magnetic fields (MF) of 50 Hz at 1.2 microT as well as 100 microT cause uncoupling of inhibitory pathways of adenylyl cyclase mediated by melatonin 1a receptor in MF-sensitive MCF-7 cells

Magnetic fields (MF) of 60 Hz at 1.2 microT were previously shown to inhibit the antiproliferative effect of melatonin on MCF-7 cells (Liburdy,R.P., 1993, J. Pimeal Res. 14, 89-97). In addition, three laboratories (Blackman,C.F. and Benane,S.G., 1998; Luben,R.A. and Morgan,A.P., 1998; Morris,J.E., Chrisler,W.B., Miller,D.L., Sasser,L.B. and Anderson,L.E., 1998; 20th Annual Meeting of the Bioelectromagnetics Society, At. Pete Beach, FL) independently reported results consistent with this finding. In this study, we investigated the molecular basis of the biological effects of MF using MCF-7 cells. Only 1a melatonin receptors were identified by the [125I]melatonin binding assay and RT-PCR analysis. Moreover, preceding exposures to MF of 100 microT for 3, 5 and 7 days blocked the melatonin-induced inhibition of cAMP accumulation in a time-dependent manner, while none of the melatonin receptor functions or GTPase and adenylyl cyclase activities were affected. Estrogen-evoked cell proliferation was not altered by MF either. Exposure to 1.2 microT MF exerted the same effects on the melatonin-signaling pathway as that to 100 microT. Thus, this is the first study to provide evidence that MF may cause uncoupling of signal transduction from melatonin receptors to adenylyl cyclase.

Induction of apoptosis in mouse thymocytes by cadmium

In the thymus apoptosis is an important process in T cell maturation and differentiation. Cadmium (Cd) is an ubiquitous toxic metal that is capable of modulating immune responses. To investigate the induction of apoptosis and immunomodulation by environmental chemicals, we cultured mouse thymocytes with Cd and/or dexamethasone (DEX). DNA fragmentation was analyzed by gel electrophoresis, ELISA and flow cytometry. Treatment with either Cd or DEX induced DNA fragmentation in the thymocytes. Exposure to 10 microM Cd killed thymocytes by apoptosis rather than necrosis. However, no synergistic or additive effect was observed in the induction of apoptosis when DEX was added to the Cd. These results suggest that Cd may modulate the function of the thymus by the induction of apoptosis through mechanisms that differ from those used by DEX.

Zinc stimulates DNA synthesis during its antiapoptotic action independently with increments of an antiapoptotic protein, Bcl-2, in porcine kidney LLC-PK(1) cells

Cadmium, an environmental pollutant, caused nephroptosis that was inhibitable by zinc. The mechanism of the antiapoptotic action of zinc is poorly understood. In this study, we found the stimulation of DNA synthesis, as assessed by bromodeoxyuridine incorporation, during prevention by zinc of apoptosis, suggesting that the proliferactive nature of zinc contributes to its inhibition of apoptosis. This finding was consistent with the result that the cells driven by dialyzed fetal bovine serum were resistant to apoptotic stimuli of cadmium. Furthermore, zinc activated the expression of endogenous Bcl-2 proteins. However, overexpression of Bcl-2 proteins by transfection did not facilitate zinc-mediated DNA synthesis. Thus, one possible role of zinc in the prevention of apoptosis is to promote DNA synthesis independently with activation of antiapoptotic proteins Bcl-2.

Cadmium-bound metallothionein induces apoptosis in rat kidneys, but not in cultured kidney LLC-PK1 cells

The ability of cadmium-bound metallothionein(Cd-MT) to induce apoptosis was investigated in vivo and in vitro. Administration of purified Cd-MT (0.15 mg MT bound Cd per kg body weight) to the rat induces DNA fragmentation, a biochemical characteristic of apoptosis in the kidney at 16 h, which was detectable by ethidium bromide staining on an agarose gel. It was still detected 24 h after administration. Induction of apoptosis by Cd-MT was specific to kidney; it was not observed in cerebrum, cerebellum, heart, lung, liver, testis, dorsolateral prostate, and ventral prostate. In contrast, addition of Cd-MT (0.01-100 microM) to the cultured porcine kidney LLC-PK1 cells failed to induce apoptosis under the condition where cadmium chloride (10 microM) did. There was no additivity of induction of apoptosis by CdCl2 (10 microM) in the presence of Cd-MT (0.01-100 microM). To examine the effect of intracellular MT on cadmium-induced apoptosis in cultured cells, new cell lines were established, which constitutively produce MT, being termed as Cd(r)-LLC-PK1 cells since Cd-MT exogenously added had much less permeability to the cultured cells. Followed by exposure of wild-type LLC-PK1 cells to 50 microM CdCl2 for 24 h, the surviving cells(Cd(r)-LLC-PK1 cells) induce MT at the level of 1.9 microg/2 x 10(6) cells. In Cd(r)-LLC-PK1 cells, 10 microM CdCl2 failed to induce apoptosis, but 60 microM CdCl2 could exert the apoptotic response, indicating that intracellular MT which was induced by CdCl2 did not facilitate CdCl2-elicited apoptosis. Furthermore, chromatin in rat kidneys was condensed by Cd-MT, but not that in LLC-PK1 cells. Thus, Cd-MT induces apoptosis in rat kidneys, but not in the cultured renal cells, suggesting that the ionic form of cadmium was required for programmed cell death.

Expression and localization of brain ankyrin isoforms and related proteins during early developmental stages of rat nervous system

Expression and localization of two isoforms of brain ankyrin, 440- and 220-kDa ankyrinB, were studied in the developing nervous system of the rat fetus. The 440-kDa ankyrinB appeared on as early as embryonic day 13, and its level increased progressively toward the day of birth, which was similar to the expression pattern of growth-associated protein (GAP)-43, a well-established axonal protein. On the other hand, 220-kDa ankyrinB was expressed at a low level but constitutively throughout the latter prenatal period and was a major isoform even before embryonic day 14. Whereas the localization of 440-kDa ankyrinB was essentially confined to the axons, judging from the similarity with that of GAP-43, 220-kDa ankyrinB showed a rather general distribution in neural tissue. The localization of L1, known as an ankyrinB-binding protein, was similar to that of 440-kDa ankyrinB in the brain tissue, whereas it was similar to that of 220-kDa ankyrinB in cultured neurons, suggesting that the interaction of L1 with brain ankyrins in neurons is affected by their environment.

c-myc is not involved in cadmium-elicited apoptotic pathway in porcine kidney LLC-PK1 cells

Cadmium chloride can induce DNA fragmentation, a biochemical characteristics of apoptosis in renal epithelial LLC-PK1 cells. Studies of cadmium cytotoxicity demonstrated that cadmium activates c-myc transcription. In this study, we investigated whether c-myc is a necessary component of cadmium-induced apoptosis. By kinetic analysis, transient activation of c-myc transcript by cadmium occurred before DNA fragmentation was induced by the metal, indicating an apparent correlation between induction of c-myc mRNA and promotion of apoptosis. However, even when using actinomycin D to block transcriptional activation of c-myc, or antisense oligodeoxynucleotide complementary to c-myc to block translation of c-myc, cadmium could still induce apoptosis. Thus, our data show that cadmium elicits apoptosis by a mechanism other than regulation of c-myc expression: transcriptional activation of c-myc during apoptosis is not always involved in the cell-death events.

Apoptosis in rat renal proximal tubular cells induced by cadmium

Cadmium chloride can induce DNA fragmentation, a biochemical characteristic of apoptosis in renal epithelial LLC-PK, cells. This study was extended to determine the in vivo effects of this heavy metal on apoptosis. Nephrotoxicity was induced by a single intravenous administration of cadmium-metallothionein (0.15 mg metallothionein-bound cadmium/kg body weight) to male Jcl:Wistar rats. DNA fragmentation was seen in the kidney 12 h after injection of cadmium-metallothionein without a concurrent release of lactate dehydrogenase in urine. Cycloheximide (3 mg/kg) inhibited cadmium-induced DNA fragmentation, suggesting that protein synthesis might be required for the induction of cell death by this metal. Apoptotic cells were identified in proximal tubular cells by in situ DNA 3'-end labeling. Furthermore, chromatin condensation in the apoptotic population of renal proximal tubular cells was noted. Data thus suggest that cadmium produces biochemical and morphological alterations in kidney, which are characteristic features seen in apoptosis.

Cadmium-induced DNA fragmentation is inhibitable by zinc in porcine kidney LLC-PK1 cells

DNA fragmentation was induced by the addition of cadmium (10 microM) to cultured LLC-PK1 cells, resulting in cell death. The cells were able to survive exposures of 10 microM cadmium without change in morphology, but most had rounded by 40 microM. Other metals tested such as Cu2+, Co2+, Ni2+, and Pb2+ had much lower ability to induce DNA fragmentation in LLC-PK1 cells under the same conditions as used for cadmium, indicating that the fragmentation seen in kidney cells is cadmium-specific. DNA fragmentation induced by 10 microM cadmium was completely inhibited using an equimolar concentration of a cell-permeant chelator specific for heavy metals, N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine. Furthermore, the apoptotic mechanism evoked by 10 microM cadmium was blocked by 50 microM zinc which when used alone has no capacity for DNA fragmentation.

The rat angiotensin II AT1A receptor couples with three different signal transduction pathways

To examine whether the subpopulation of the rat type 1 angiotensin II (AII) receptor (AT1A) couples with a single or multiple signal transduction pathways, we constructed Chinese hamster ovary (CHO) cell lines producing the recombinant receptor. The expressed AT1A receptor exhibits typical pharmacological characteristics of the AT1 receptor, known to mediate the main physiological function of AII. Addition of AII to the CHO cells induced a rapid, transient increase in intracellular free Ca2+ concentrations ([Ca2+]i) followed by a lower, sustained phase. Nicardipine, a blocker of voltage-dependent L-type Ca2+ channels, attenuated the transient [Ca2+]i response and abolished the sustained phase. The transient phase was also reduced dose-dependently by the phospholipase C inhibitor neomycin. Furthermore, AII inhibited forskolin-evoked cAMP accumulation. These data suggest, although another subpopulation named AT1B is present, that the rat AT1A receptor can independently couple with all three signal transduction pathways known to be induced by AII: i.e., i) activation of phospholipase C resulting in InsP3 generation with a subsequent release of intracellularly stored Ca2+, ii) activation of dihydropyridine-sensitive voltage-dependent Ca2+ channels, and iii) inhibition of adenylate cyclase activity.

Molecular cloning of the receptor for human antidiuretic hormone

Antidiuresis, the recovery of water from the lumen of the renal collecting tubule, is regulated by the hypothalamic release of antidiuretic hormone (ADH), which binds to specific receptors on renal collecting tubule cells, stimulates adenylyl cyclase and promotes the cyclic AMP-mediated incorporation of water pores into the luminal surface of these cells. We report here the isolation of the human ADH receptor gene using a genomic expression cloning approach. The gene was used to clone the complementary DNA from a human renal library. The deduced amino-acid sequence of the receptor yields a hydropathy profile characteristic of receptors with seven putative transmembrane regions. This and the comparison with other cloned receptors indicates that the ADH receptor is a member of the superfamily of G-protein-coupled receptors.

Radioimmunoimaging of tumors with radioactive antibody against a glycoprotein (GP68) found in developing mouse brain

The in vivo localization of a polyclonal antibody (pAb) against a glycoprotein with a molecular mass of 68 kDa (GP68), which was found in developing mouse brain, was studied in murine tumor models to evaluate potential applications of this antibody for in vivo radioimmunodetection and/or therapy of cancer. The tissue distribution of 125I-labeled GP68 pAb 3 days after i.v. injection into mice bearing four different kinds of solid tumor revealed a high uptake ratio by adenocarcinoma 755 and Lewis 3LL lung cancer. In contrast, the uptake ratio was low in mice bearing Ehrlich solid tumor and sarcoma-180 (S-180). These uptake ratios accorded well with the in vitro binding activity of this antibody with the tumor cells. In an immunoscintigraphic study, adenocarcinoma 755 was successfully visualized with 67Ga-labeled GP68 pAb. The results of these biodistribution and in vivo radioimmunoscintigraphic studies suggest that GP68 antibody may be applicable to the diagnosis and/or therapy of cancer.

Tissue distribution of radioiodinated neoglycoproteins and mammalian lectins

Quantitation of tissue distribution of radioiodinated neoglycoproteins 1 h after intravenous injection into mice allowed to evaluate their suitability to uncover potential selectivity in tracer retention. Variations within the panel of neoglycoproteins were introduced to the carbohydrate determinant, its density and linkage to the carrier. Five arrays of neoglycoproteins, encompassing up to twelve different carbohydrate moieties were used. The individual response on the level of organ content showed differences, accounted for by carbohydrate structure and density. However, increase in sugar density eventually caused general decrease in tissue retention, emphasizing the importance of synthetic parameters. Attachment of sugar residues to the spacer via primarily the C-6 group of monosaccharides led to rather prolonged survival in circulation of the resulting neoglycoprotein compared to the application of neoglycoproteins with p-aminophenyl glycosides as derivatives for coupling. Besides applying neoglycoproteins tissue uptake was also measured for several organs, when four mammalian lectins were employed as radiotracers. These lectins bind to cellular carbohydrate ligands, namely beta-galactosides, alpha-fucosides or heparin. Differences were measured for retention in liver, kidneys, spleen, stomach, thymus and bone marrow. The distinct properties of different tissues with respect to binding of neoglycoproteins as well as to endogenous lectins, exhibiting a certain degree of selectivity, are a step within the framework to attempt to therapeutically exploit the carrier potential of probes by recognitive protein-carbohydrate interactions.

Stimulation of Na-K-Cl cotransport in cultured vascular endothelial cells by atrial natriuretic peptide

Vascular endothelial cells have been shown to contain atrial natriuretic peptide (ANP)-sensitive Na-K-Cl cotransport system whose activity is regulated by intracellular cGMP levels. Addition of ANP to culture medium stimulated 86Rb+ uptake in bovine endothelial cells with a concomitant increase in cGMP contents. This action of ANP was mimicked by 8-bromo-cGMP and completely diminished by furosemide. These results indicate that ANP selectively activates the Na-K-Cl cotransporter in vascular endothelial cells via cGMP and offer new insight into the physiological significance of endothelial ANP receptors.

Mechanism of activation of particulate guanylate cyclase by atrial natriuretic peptide as deduced from radiation inactivation analysis

The interaction between the receptor (Rc) for atrial natriuretic peptide (ANP) and the effector enzyme particulate guanylate cyclase (GC) has been studied by radiation inactivation. Irradiation of bovine lung membranes produced an increase in GC activity at low radiation doses followed by a dose-dependent reduction at higher doses. This deviation from linearity in the inactivation curve disappeared when lung membranes were pretreated with ANP. Essentially identical results were also obtained with adrenal membranes. Based on these radiation inactivation data, the following dissociative mechanism of activation of particulate guanylate cyclase by ANP has been proposed: Rc.GC(inactive) + ANP----Rc.ANP + GC(active).

Inhibition of atrial natriuretic peptide-induced cyclic GMP accumulation in the bovine endothelial cells with anti-atrial natriuretic peptide receptor antiserum

Using an antiserum raised against the purified atrial natriuretic peptide (ANP) receptor that has a disulfide-linked homodimeric structure and represents one subtype of the multiple ANP receptors, we showed that the receptor is coupled to the guanylate cyclase activation; formerly, this type of ANP receptor is not considered to be coupled to the cyclase. The specificity of the antiserum was determined by immunoblot analysis and immunoprecipitation. The anti-receptor antiserum did not compete with 125I-ANP for binding to the receptor but it lowered the affinity of the receptor. When added to bovine endothelial cell cultures, the antiserum blocked the cyclic GMP response of the cells triggered by ANP. These results indicate that the subtype of the ANP receptor recognized by the antiserum is responsible for the activation of particulate guanylate cyclase as well as the double function type receptor that has been assumed to contain both the receptor domain and the catalytic domain for cGMP synthesis on the same molecule. The presence of dissociative complexes of ANP receptor and particulate guanylate cyclase was also demonstrated by radiation inactivation analysis.

Lack of atrial natriuretic peptide receptors in human aldosteronoma

The effect of synthetic alpha-human atrial natriuretic peptide (ANP) on aldosterone secretion was studied in human aldosterone producing adrenocortical adenoma obtained surgically from a patient with primary aldosteronism and in human apparently normal adjacent adrenal cortical tissues obtained from a patient with pheochromocytoma, in vitro. Apparently normal adrenal cortical tissue responded to ANP with the known inhibition of aldosterone secretion. In contrast, the aldosterone producing adenoma did not respond to ANP. When stimulated by either ACTH or angiotensin II, there is no inhibition by ANP in the adenoma tissue, whereas normal tissue was inhibited. Immunohistochemical examination utilizing an ANP-receptor antiserum demonstrated that there was no evidence of binding site in the cortical adenoma, in contrast, zona glomerulosa cells in the cortical tissues adjacent to either aldosterone producing adenoma or pheochromocytoma were densely stained. This apparent lack of ANP-receptors is an associated finding with the hypersecretion of aldosterone in the aldosterone producing adenoma.

Presence of functional receptors for atrial natriuretic peptide in human pheochromocytoma

Pheochromocytoma, a catecholamine-secreting adrenomedullary tumor, has been shown to contain the functional receptor for human atrial natriuretic peptide(h-ANP). Release of catecholamines from tissue slices of pheochromocytoma was inhibited by h-ANP in a dose-dependent manner. Binding assays using 125I-ANP revealed a single class of high affinity binding sites for ANP. When covalently tagged with 125I-ANP and electrophoresed under non-reducing and reducing conditions, the receptor migrated as a 140-kDa band and a 70-kDa band, respectively, reflecting its disulfide-linked subunit structure. The presence of ANP receptor in pheochromocytoma was further demonstrated by immunohistochemistry; the tumor was positively stained with an antireceptor antiserum. The antiserum was also useful to establish the zona glomerulosa localization of ANP receptor in the normal human adrenal gland.

Purification of atrial natriuretic peptide receptor from bovine lung. Evidence for a disulfide-linked subunit structure

The receptor for atrial natriuretic peptide (ANP) was purified to apparent homogeneity from bovine lung by a combination of detergent extraction, ammonium sulfate precipitation, and affinity chromatography on ANP-Affi-Gel 10. The Mr of the purified receptor is about 140,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After reduction, the protein migrated as a single band with an Mr near 70,000. NH2-terminal sequence analysis of the purified material revealed only one sequence, indicating that the ANP receptor is composed of two probably identical subunits held together by disulfide bond(s), although it remains possible that one of the subunits is blocked at the NH2 terminus. Antibody was produced to the nonreduced Mr = 140,000 species and shown to interact with detergent-solubilized forms of the lung and kidney ANP receptor.

Physical and functional association of the atrial natriuretic peptide receptor with particulate guanylate cyclase as demonstrated using detergent extracts of bovine lung membranes

Coupling of the atrial natriuretic peptide (ANP) receptor to particulate guanylate cyclase has been demonstrated kinetically and chromatographically using bovine lung plasma membranes and their detergent extracts. Addition of ANP to the membrane suspension stimulated guanylate cyclase activity 2-5-fold indicating the presence of ANP-sensitive particulate guanylate cyclase. The enzyme retained the ability to respond to ANP even after solubilization with digitonin. Characterization of the solubilized enzyme by gel filtration and affinity chromatography revealed that the ANP receptor and particulate guanylate cyclase exist as a functionally but not covalently linked stable complex.