The apolipoprotein(a) size, pentanucleotide repeat, C/T(+93) polymorphisms of apolipoprotein(a) gene, serum lipoprotein(a) concentrations and their relationship in a Korean population

BACKGROUND

In addition to apolipoprotein(a) [apo(a)] kringle 4 variable number of tandem repeat (K4-VNTR), pentanucleotide repeat polymorphism (PNRP) and C/T(+93) polymorphism [C/T(+93)] of apo(a) gene have been suggested to be related to lipoprotein(a) [Lp(a)] concentration. We studied the distribution of these genetic polymorphisms and their relationship with Lp(a) concentrations in a Korean population.

METHODS

One hundred thirty-two Korean adults were examined. Lp(a) was measured with enzyme-linked immunosorbent assay (ELISA). Apo(a) K4-VNTR was measured by high-resolution SDS-agarose gel separation and ECL Western blotting method. PNRP was measured after DNA amplification. The C/T(+93) ratio was measured by a amplification refractory mutation system.

RESULTS

Lp(a) was inversely correlated with K4-VNTR (r=0.732, p<0.0001), but was associated neither with any PNRP haplotype nor with C/T(+93) by multiple regression analysis, although we found a significant decrease of Lp(a) in PNRP 9/9 individuals (p<0.01). There was a strong linkage disequilibrium between 9 haplotypes of PNRP and the T haplotype of C/T(+93).

CONCLUSIONS

Inverse relationship between serum Lp(a) and K4 number of apo(a) was confirmed in normal Korean adults. PNRP 9/9 genotype appeared to have a reducing effect on Lp(a), but neither 9 haplotype heterozygotes of PNRP nor the T haplotype C/T(+93) affected Lp(a) concentrations in Koreans.

Evaluation of E1B-mutant Replicating Adenoviruses for Cancer Gene Therapy

PURPOSE

Gene-attenuated replication-competent adenoviruses are emerging as a promising new modality for the treatment of cancer. In an effort to continually improve upon cancer gene therapy, we have modified gene- attenuated replication-competent adenoviruses so as to cause them to replicate efficiently and lyse the infected cancer cells more effectively.

MATERIALS AND METHODS

We modified the E1 region of the adenovirus (Ad) systematically, generating Ad-deltaE1B19, Ad-deltaE1B55, Ad-deltaE1B19/55, and Ad-WT. The cytopathic effects (CPE) and viral replication of these four gene modified adenoviruses were compared, and the morphology and DNA fragmentation of the infected cells was evaluated.

RESULTS

Among the constructed adenoviruses, E1B 19kD-inactivated adenovirus (Ad-deltaE1B19) was the most potent, inducing the largest-sized plaques and markedCPE. Moreover, cells infected with Ad-deltaE1B19 showed complete cell lysis with disintegrated cellular structure whereas cells infected with Ad-WT maintained intact cellular and nuclear membrane with properly structured organelles. TUNEL assay was also used to monitor DNA integrity, and a more profound induction of apoptosis was observed in the Ad-deltaE1B19 infected cells in comparison to wild type adenovirus infected cells.

CONCLUSION

We demonstrate that the inactivation of the E1B19kD gene in a replicating adenovirus leads to increased CPE, rapid viral release, improved cell-to-cell viral spread and increased induction of apoptosis.

Expression profile of histone deacetylase 1 in gastric cancer tissues

Although histone deacetylases (HDACs) appear to play a crucial role in carcinogenesis, the expression status of HDACs in primary human cancer tissues has not yet been reported. In this study, we investigated the expression level of HDAC1 in 25 paired primary human gastric cancer (GC) tissues and corresponding normal tissues through semi-quantitative RT-PCR and immunoblot analysis. The HDAC1 expression pattern was also topologically examined through immunohistochemistry. Overexpression of HDAC1 mRNA was detected in 68% of GC tissues (17 of 25), and the relative density of HDAC1 mRNA in GC tissue was increased 1.8-fold versus the normal counterpart (P < 0.01). Elevated expression of HDAC1 protein was also detected in 61% of GC samples (11 of 18), which also showed an increased mRNA level of HDAC. Immunohistochemically, overexpression of HDAC1 was predominantly localized in the nuclei of most neoplastic cells, including embolic tumor cells, whereas normal glandular epithelial cells revealed only weak HDAC1 expression that was focal in distribution. Thus, the present study clearly demonstrates that HDAC1 is overexpressed in GC and probably plays a significant role in gastric carcinogenesis.

Regulation of mitochondrial sn-glycerol-3-phosphate acyltransferase activity: response to feeding status is unique in various rat tissues and is discordant with protein expression

Triacylglycerol plays a critical role in an organism's ability to withstand fuel deprivation, and dysregulation of triacylglycerol synthesis is important in the development of diseases such as obesity and diabetes. Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the initial and committed step of glycerolipid synthesis and is therefore a potential site for regulation of triacylglycerol synthesis. Because several studies suggest that triacylglycerol synthesis is linked to the mitochondrial isoform, we studied mitochondrial GPAT expression and the effect of feeding status on the regulation of mitochondrial GPAT in various rat tissues. Liver, adipose, and soleus muscle have high levels of GPAT mRNA, but low protein expression, whereas heart and adrenal, tissues with low GPAT mRNA abundance, have the highest GPAT protein expression. In addition, heart, which has the highest expression of mitochondrial GPAT protein, has low mitochondrial GPAT specific activity (0.02 nmol/min/mg). Liver and adipose have the highest mitochondrial GPAT specific activity (0.17 nmol/min/mg), but very low protein expression. Discrepancies between GPAT protein expression and activity suggest that mitochondrial GPAT may be regulated acutely. In response to a 48-h fast, liver and adipose mitochondrial GPAT protein expression and activity decrease 30-50%. After 24-h refeeding of either chow or high-sucrose diet, mitochondrial GPAT protein expression and activity overshoot normal levels 30-60%. In kidney, mitochondrial GPAT protein and activity increase 65 and 30%, respectively, with refeeding, whereas in the heart, mitochondrial GPAT activity increases 2.3-fold after a fast, with no change in protein expression. We also found that hepatic mitochondrial GPAT activity in the neonatal rat constitutes a lower percentage of the total GPAT activity than in the adult. We postulate that GPAT expression is modulated uniquely in each tissue according to specific needs for triacylglycerol storage.

Effect of the absence of heat shock protein 70.1 (hsp70.1) on retinal photoreceptors in normal and rd mice

The purposes of this study are to elucidate the retinal changes of heat shock protein 70.1 (hsp70.1) knockout mice and to compare them between in normal and in retinal degeneration (rd) mice. Eyes of hsp70.1 wild type (+/+) and knockout (-/-) mice in the C57BL/6 or FVB genetic backgrounds respectively, which were reared in the normal environment, were examined by fundus photography, electroretinography, light microscopy, terminal dUTP nick-end labeling (TUNEL) stain, and immunohistochemistry. In C57BL/6 mice, fundus photography showed no changes between hsp70.1+/+ and -/- mice at 1 and 6 months of age. Electroretinographic examination showed a tendency of decreased amplitude of a- and b-wave with aging in both genotype, but there were not different statistically. The ratios of the thickness of inner nuclear and outer nuclear layer to the retinal thickness were respectively decreased with aging in both genotype, but there were not different statstically. TUNEL assay showed a few positively labeled cells in the ganglion cell, inner nuclear and outer nuclear layers and the immunohistochemistry showed no immunopositivity of hsp70 in the inner segments of photoreceptor cell layer in both genotype. In rd mice, fundus photography showed a narrowing of the retinal vessels at the age of 4 weeks, however, there were no differences of retinal changes including pigment epithelial layer in both genotype. Electroretinographic examination at the postnatal 2, 3 and 4 weeks showed no differences between them. Loss of photoreceptor cell and outer nuclear layers showed no differences in both genotype. In conclusion, there were no differences of the retinal changes at least under the normal environmental condition in hsp70.1+/+ and -/- mice. These results show that hsp70.1-/- mice can be used to study the role of hsp70.1 to the external stress to the retina.

Expression of mucosal cyto-chemokine mRNAs in patients with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori-induced destruction of the gastroduodenal mucosal barrier is initiated with mucosal infiltration of inflammatory cells. Cytokines and chemokines have been suggested to play important roles in the migration and activation of these inflammatory cells into the mucosa. The present study aimed to investigate expression rates of cyto-chemokine mRNAs using gastric mucosal biopsy specimens.

METHODS

In 98 patients infected with Helicobacter pylori, mucosal mRNA expression rates of cytokines (IL-1 beta, IL-6, and IL-10), C-C chemokines (macrophage inflammatory protein 1 alpha (MIP-1 alpha), and macrophage inflammatory protein 1 beta (MIP-1 beta), monocyte chemotactic and activating factor (MCAF), regulated on activation, normal T cell expressed and presumably secreted (RANTES)) and C-X-C chemokines (IL-8 and growth regulated a (GRO-alpha)) were examined using reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The expression rates of mRNA for IL-8, GRO-alpha, MIP-1 alpha and RANTES were significantly more increased in H. pylori-positive patients than in H. pylori-negative patients. However, the expressions of IL-1 beta, IL-6 and IL-10 mRNA were statistically not different between two groups. After eradication of H. pylori, expressions of mRNA for three cytokines (IL-1 beta, IL-6 and IL-10), four C-C chemokines (MIP-1 alpha, MIP-1 beta, MCAF and RANTES) and two C-X-C chemokines (IL-8 and GRO-alpha) were significantly decreased.

CONCLUSION

These results suggest that C-X-C chemokines and some C-C chemokines play important roles in H. pylori-associated peptic ulcer diseases.

Combined chemotherapy and radiation versus radiation alone in the management of localized angiocentric lymphoma of the head and neck

BACKGROUND AND PURPOSE

To clarify the clinical benefit derived from the combined modality therapy (CMT) comprised of chemotherapy and involved-field radiotherapy (XRT) for stage I and II angiocentric lymphomas of the head and neck.

MATERIAL AND METHODS

Of 143 patients with angiocentric lymphoma of the head and neck treated at the Yonsei Cancer Center between 1976 and 1995, 104 patients (XRT group) received involved-field XRT alone with a median dose of 50.4 Gy (range: 20-70 Gy), while 39 patients (CMT group) received a median three cycles (range: 1-6 cycles) of chemotherapy before starting involved-field XRT. The response rate, patterns of failure, complications, and survival data of the XRT group were compared with those of the CMT group.

RESULTS

Despite a higher response rate, local failure was the most common pattern of failure in patients of the both groups. The patterns of failure, including the systemic relapse rate were not influenced by the addition of combination chemotherapy. Although both modalities were well tolerated by the majority of patients, aberrant immunologic disorders or medical illnesses, such as a hemophagocytic syndrome, sepsis, intractable hemorrhage, or the evolution of second primary malignancies were more frequently observed in patients of the CMT group. The prognosis of patients in the XRT group was relatively poor, with a 5-year overall actuarial survival rate of 38% and disease-free survival rate of 32%, respectively. However, their clinical outcome was not altered by the addition of systemic chemotherapy. Achieving complete remission was the most important prognostic factor on univariate and multivariate analyses, but treatment modality was not found to be a prognostic variable influencing survival.

CONCLUSIONS

Involved-field XRT alone for angiocentric lymphoma of the head and neck was insufficient to achieve an improved survival rate, but the combination of chemotherapy and involved-field XRT failed to demonstrate any therapeutic advantage over involved-field XRT alone.

Enantioseparation of chiral amino acids as the N(O,S)-ethoxycarbonylated diastereomeric esters by achiral dual-capillary column gas chromatography

The enantioseparation of 30 racemic amino acids in a single analysis is described for the determination of their absolute configurations. Two-phase extractive ethoxycarbonyl (EOC) reaction with ethyl chloroformate present in the dichloromethane phase was performed to recover amino acids from alkaline aqueous solutions. The resulting N(O,S)-EOC amino acids extracted into an organic solvent after acidification were reacted with a chiral alcohol such as (S)-(+)-3-methylbutan-2-ol, (S)-(+)-butan-2-ol and (S)-(+)-octan-2-ol for gas chromatographic analysis on achiral dual-capillary DB-5 and DB-17 columns of different polarities. Among the chiral reagents examined, (S)-(+)-3-methylbutan-2-ol provided the best diastereomeric structures in resolving all the racemic amino acids into their enantiomeric pairs with high resolution factors (1.2-8.0). Moreover, the temperature-programmed retention index (I) values measured on the two columns were characteristic of each enantiomer. Hence simple I matching with the reference values was useful in cross-checking for chemical identification and also chiral discrimination. When the present method was applied to a fermented dairy product (Yakult), D-alanine, D-aspartic acid, D-glutamic acid and D-proline were positively detected along with their respective L-forms in addition to glycine.

Induction of oral tolerance to Japanese cedar pollen

Oral tolerance is thought to play a role in preventing allergic responses and immune-mediated diseases. An improved mouse model of the oral tolerance to Japanese cedar pollen (JCP) as antigen was developed in order to detect induction of the tolerance, and the immunological characteristics of this model were also elucidated. Oral tolerance was induced by C3H/ HeN mice given an oral administration of 10 mg JCP 7 days before immunization with an i.p. injection of 0.1 mg JCP in complete Freunds adjuvant (CFA). The effects of oral JCP on systemic immunity were assessed by enzyme-linked immunosorbent assay (ELISA) of immunoglobulin (Ig) levels in serum collected on day 7 or 14 after immunization. Oral tolerance to JCP was adequately induced on day 7 after immunization and was more effective in C3H/HeN mice than in BALB/c mice. The tolerance was primarily concerned with the decreased serum levels of antigen-specific IgG. In these mice, oral administration of JCP also suppressed various immune responses to the antigen including delayed-type hypersensitivity (DTH), total IgE level and anti-JCP IgG1 level. The suppression of these immune responses by the oral antigen was associated with a significant reduction in interleukin-4 (IL-4) production. These findings therefore indicate that this C3H/HeN mice model has potential use in detecting the induction of oral tolerance by JCP, and suggest that this tolerance model may be effective in the treatment and prevention of allergic responses caused by the antigen.

Induction of G(2)/M phase arrest and apoptosis by a new synthetic anti-cancer agent, DW2282, in promyelocytic leukemia (HL-60) cells

We studied the effect of DW2282-,[(S)-(+)-4-phenyl-1-[N-(4-aminobenzoyl)-indoline-5-sulfonyl-4,5-dihydro-2-imidazolone].hydrochloride], a newly developed anti-cancer agent, on cell proliferation, cell cycle progression, and induction of apoptosis in human promyelocytic leukemia (HL-60) cells. DW2282, a diarylsulfonylurea compound, was cytotoxic to HL-60 cells, with an IC(50) of 1.0 microg/mL. Treatment with DW2282 fragmented DNA in a concentration- and time-dependent manner, suggesting that these cells underwent apoptosis. Flow cytometric analysis further confirmed that DW2282-treated HL-60 cells were hypodiploid, in terms of DNA content, and were arrested at the G(2)/M phase. The cell cycle arrest was reversible upon the removal of DW2282. HL-60 cells also underwent distinct morphological changes in response to DW2282 treatment, including the appearance of elongated cells with conical tails and other apoptotic characteristics. G(2)/M phase cell cycle arrest was accompanied by a decrease in the levels of cdc2, a protein that plays a critical role for progression through the G(2)/M phase. Treatment of HL-60 cells with DW2282 was also associated with decreased levels of the anti-apoptotic protein Bcl-2, activation of caspase-3, and proteolytic cleavage of poly(ADP-ribose) polymerase. Taken together, these results demonstrate that DW2282 dramatically suppressed HL-60 cell growth by inducing apoptosis after G(2)/M phase arrest. These findings are consistent with the possibility that G(2)/M phase arrest was mediated by the down-regulation of cdc2 levels in HL-60 cells. The data also suggest that DW2282 triggered apoptosis by decreasing Bcl-2 levels and activating caspase-3 protease. These results provide important new information towards understanding the mechanisms by which DW2282 and other diarylsulfonylureas mediate their therapeutic effects.

Augmented expression of peroxiredoxin I in lung cancer

Comparative proteome analysis was performed between human normal (BEAS 2B) and malignant (A549) lung epithelial cells in an attempt to identify novel biomarkers of lung cancer. Approximately 500 protein spots could be separated by mini two-dimensional electrophoresis and visualized with Coomassie blue R-250. Among those relatively abundant proteins, eight spots were changed more than twofold reproducibly and identified by peptide mass fingerprints using mass spectrometry and database search. The increased proteins in A549 were aldehyde dehydrogenase, peroxiredoxin I, fatty acid binding protein, aldoketoreductase, and destrin, whereas the decreased proteins were galectin-1, transgelin, and stathmin. Since human lung is exposed to continuous oxidative stress, antioxidant enzyme peroxiredoxin I was selected for further investigation and its augmented expression was confirmed in cancer tissues compared to normal tissues from lung cancer patients, suggesting peroxiredoxin I as a potential biomarker of lung cancer.

Folding and stability of sweet protein single-chain monellin. An insight to protein engineering

Engineered single-chain monellin (SCM) proteins were constructed by recombinant technology without disrupting the topology and sweet activity of native protein. Data from 8-anilinonaphthalene-1-sulfonic acid fluorescence, size-exclusion chromatography, and heteronuclear NMR strongly suggest the presence of a folding intermediate at 1.5 m GdnHCl for SCM protein. The structural feature of the folding intermediate from NMR data reveals that the secondary structures became mostly unstable, and protein experiences a dynamic equilibrium between native and unfolded state. All backbone amide protons exchange within 10 min, which imply that no stable hydrogen bonds exist in the secondary structural regions in the folding intermediate. From equilibrium unfolding and mutagenesis studies, the unfolding transition midpoints of mutant proteins gradually shifted toward lower denaturant concentration, indicating stability reductions of mutant proteins. Our results suggest that stability and folding pathways of SCM proteins could be regulated by a combined study of spectroscopy and mutagenesis, and these studies will provide useful information for understanding the folding kinetics of novel engineered proteins.

3-Aryl-4-aryloyl-1-(1H-imidazol-5-yl)methylpyrrole, a novel class of farnesyltransferase inhibitors

Design, synthesis and structure-activity relationship of a class of 3-aryl-4-aryloyl-1-(1H-imidazol-5-yl)methylpyrroles as farnesyltransferase inhibitors are described. Compound 7 inhibits farnesyltransferase with an IC(50) value of 4.6 nM.

Enhanced apoptosis and radiosensitization by combined 13-cis-retinoic acid and interferon-alpha2a; role of RAR-beta gene

PURPOSE

Combined use of 13-cis-retinoic acid (cRA) and interferon-alpha2a (IFNalpha) induced significant radiosensitization in human cervical cancer ME-180 cell line, whereas it failed to achieve similar radiation enhancement in HeLa cells. The differential radiosensitization could be from the difference of retinoic acid receptor (RAR) expression because RAR-beta was highly expressed in ME-180 cells in contrast to the HeLa cells where RAR-beta was not detectable. We examined the role of this gene in mediating radiosensitization by cRA and IFNalpha, and explored the mechanism of radiation-induced cell killing.

METHODS AND MATERIALS

Human cervical cancer cell lines, ME-180 and HeLa, were treated with cRA and IFNalpha followed by radiation. Apoptosis and radiosensitization were quantitated by TUNEL assay (in situ DNA nick end labeling) and colony-forming ability of surviving cells. The cells were transfected with bcl-2 gene and RAR-beta gene to test the role of these genes in mediating radiosensitization and apoptosis.

RESULTS

Synergistic radiosensitization and apoptosis was observed by combined use of cRA and IFNalpha with radiation in ME-180 cells which express high level of RAR-beta mRNA, whereas these were not seen in HeLa cells where RAR-beta mRNA is not detectable. Both radiosensitization and apoptosis were abolished by bcl-2 gene in ME-180 cells. RAR-beta gene transfection induced similar radiation enhancement and apoptosis in HeLa cells.

CONCLUSION

Apoptosis and radiation response were enhanced in the cells with high level of RAR-beta mRNA expression. The RAR-beta gene appears to mediate the radiation-induced apoptosis by cRA and IFNalpha. These findings indicate that presence of RAR-beta in the cancer cells could be exploited for patient selection in using these drugs for apoptosis and radiosensitization.

A case of persistent endometriosis after total hysterectomy with both salpingo-oophorectomy managed by radiation therapy

Persistent endometriosis after total hysterectomy and both salpingo-oophorectomy (TH with BSO) is a rare condition and the etiology is uncertain. The exact incidence of persistent endometriosis after definitive surgery is not known. In addition, the treatment of persistent endometriosis after complete surgical excision is controversial. We report a case of persistent endometriosis with vaginal and sigmoid-colonic invasion after TH with BSO. The lesions were not responsive to hormonal therapy. The patient was managed successfully by therapeutic pelvic radiation.

Mammary gland adenocarcinoma in a mandrill (Mandrillus sphinix)

A 22-year-old female mandrill (Mandrillus sphinix) with continuously growing mass at the right mammary gland area was found dead, and a postmortem examination was performed. At necropsy, an elevated firm subcutaneous mass about 5 cm in diameter was present at the right mammary gland area. Axillary, mediastinal, and tracheobronchial lymph nodes were enlarged 2 to 4 times their normal sizes. Numerous metastatic foci 2 to 5 mm in diameter were scattered in the lung. Histologically, the tumor was diagnosed as mammary gland adenocarcinoma. Metastasis to the regional lymph nodes and lung was also confirmed. This is the first reported case of a mammary gland tumor in mandrill in Asia.

Rac1 regulates heat shock responses by reorganization of vimentin filaments: identification using MALDI-TOF MS

Rac1 has been implicated in a wide variety of biological processes, including actin remodeling and various signaling cascades. Here we have examined whether Rac1 might be involved in heat shock-induced cell signaling. We found that Rat2 stable cells expressing a dominant negative Rac1 mutant, RacN17 (Rat2-RacN17), were significantly more tolerant to heat shock than control Rat2 cells, and simultaneously inhibited the activation of SAPK/JNK by heat shock compared to control Rat2 cells. However, no discernible effect was observed in typical heat shock responses including total protein synthesis and heat shock protein synthesis. To identify the proteins involved in this difference, we separated the proteins of both Rat2 and Rat2-RacN17 cell lines after heat shock using two-dimensional gel electrophoresis and identified the differentially expressed proteins by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) after in-gel trypsin digestion. Differentially expressed proteins between two cell lines were identified as vimentin. Rat2-RacN17 cells showed significant changes in vimentin as well as marked changes in vimentin reorganization by heat shock. The vimentin changes were identified as N-terminal head domain cleavage. These results suggest that Rac1 plays a pivotal role in the heat shock-induced signaling cascade by modifying intermediate vimentin filaments.

Degradation of isoxaben in soils and an aqueous system

The degradation of isoxaben [N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxybenzamide] was studied in soil and in an aqueous system. Soil studies were conducted in Erlenmeyer flasks (treated with 1 microg/g isoxaben) and mineralization studies in Biometer flasks (treated with 1 microg/g unlabeled and 14C-isoxaben) incubated at 23 C. Degradation in the aqueous system was performed in Erlenmeyer flasks under aerobic and anaerobic conditions incubated at 23 degrees C. Incubation mixtures were extracted at selected times and analyzed for isoxaben and degradation products by HPLC with product identification confirmed by GC-MS. After 8 weeks, 78% and 23% of the total isoxaben disappeared in nonsterile and sterile soils, respectively. After 12 weeks, approximately 1% of the labeled isoxaben was recovered as CO2 in the Biometer flask experiments; no volatile products were detected, and 5% and 33% of the total radioactivity was recovered from the nonsterile and sterile soils, respectively. In the aquatic system after 8 weeks, isoxaben had decreased from 1microg/g to 0.1 and 0.004 microg/g under aerobic and anaerobic conditions, respectively. Degradation products detected from the soil studies were 3-nitrophthalic acid and 4-methoxyphenol, and 3-nitrophthalic acid in the aqueous system studies. Microbial activity was considered to be a major factor in the degradation of isoxaben in this study.

The muscle-specific protein phosphatase PP1G/R(GL)(G(M))is essential for activation of glycogen synthase by exercise

In skeletal muscle both insulin and contractile activity are physiological stimuli for glycogen synthesis, which is thought to result in part from the dephosphorylation and activation of glycogen synthase (GS). PP1G/R(GL)(G(M)) is a glycogen/sarcoplasmic reticulum-associated type 1 phosphatase that was originally postulated to mediate insulin control of glycogen metabolism. However, we recently showed (Suzuki, Y., Lanner, C., Kim, J.-H., Vilardo, P. G., Zhang, H., Jie Yang, J., Cooper, L. D., Steele, M., Kennedy, A., Bock, C., Scrimgeour, A., Lawrence, J. C. Jr., L., and DePaoli-Roach, A. A. (2001) Mol. Cell. Biol. 21, 2683-2694) that insulin activates GS in muscle of R(GL)(G(M)) knockout (KO) mice similarly to the wild type (WT). To determine whether PP1G is involved in glycogen metabolism during muscle contractions, R(GL) KO and overexpressors (OE) were subjected to two models of contraction, in vivo treadmill running and in situ electrical stimulation. Both procedures resulted in a 2-fold increase in the GS -/+ glucose-6-P activity ratio in WT mice, but this response was completely absent in the KO mice. The KO mice, which also have a reduced GS activity associated with significantly reduced basal glycogen levels, exhibited impaired maximal exercise capacity, but contraction-induced activation of glucose transport was unaffected. The R(GL) OE mice are characterized by enhanced GS activity ratio and an approximately 3-4-fold increase in glycogen content in skeletal muscle. These animals were able to tolerate exercise normally. Stimulation of GS and glucose uptake following muscle contraction was not significantly different as compared with WT littermates. These results indicate that although PP1G/R(GL) is not necessary for activation of GS by insulin, it is essential for regulation of glycogen metabolism under basal conditions and in response to contractile activity, and may explain the reduced muscle glycogen content in the R(GL) KO mice, despite the normal insulin activation of GS.

The roles of PDZ-containing proteins in PLC-beta-mediated signaling

Mammalian phospholipase C-beta isozymes are activated by a heterotrimeric GTP-binding protein linked to various cell surface receptors. Recent reports suggest that PDZ domain proteins play a significant role of PDZ-containing proteins in the regulation of mammalian PLC-beta isozymes. PDZ-containing proteins mediate the clustering of receptors and signaling molecules and thereby regulate agonist-induced signal transduction in polarized cells such as neuronal and epithelial cells. NORPA, a Drosophila PLC-beta, is known to be a component of a signaling complex that includes TRP and rhodopsin through interaction with INAD, a PDZ-containing protein. Mammalian PLC-beta1 and -beta2 isoforms interact with a PDZ-containing protein NHERF which is coupled to Trp4, a Ca(2+) channel. In addition, PLC-beta3 specifically interacts with E3KARP, another protein closely related to NHERF, through its C-terminal PDZ-binding motif. E3KARP up-regulates the PLC-beta3 activation coupled to muscarinic receptor. In this review, the role of signaling complexes mediated by PDZ-containing proteins in the regulation of PLC-beta isoforms will be discussed.

Expression of interleukin-1 beta in lipopolysaccharide stimulated monocytes derived from patients with aneurysmal subarachnoid hemorrhage is correlated with cerebral vasospasm

Cerebral arterial vasospasm is a frequent complication after aneurysmal subarachnoid hemorrhage (SAH). Immunological activation may affect the development of vasospasm. This study measured the cytokines released from lipopolysaccharide-stimulated monocytes of SAH patients. We measured cerebral artery diameters before and after surgery for SAH. The activation index of interleukin-1 beta (IL-1 beta), but not tumor necrosis factor-alpha (TNF-alpha), was higher in patients with symptomatic vasospasm (5.6+/-1.7; n=11) than in patients without (1.8+/-0.4; n=11) (P=0.039). Furthermore, the IL-1 beta activation index was correlated with the degree of the postoperative angiographic vasospasm (correlation coefficient=-0.66, P=0.007). Individual variation in systemic immune activation, measured by monocyte-derived IL-1 beta expression levels after stimulation, may be associated with the development of vasospasm after aneurysmal SAH.

Retinoid-dependent antagonism of serum response factor transactivation mediated by transcriptional coactivator proteins

Transcriptional coactivators SRC-1 and p300 specifically interact with liganded-nuclear receptors and also modulate other transcription factors, including serum response factor (SRF). Here, we report that retinoids repress transactivation by SRF and specific interactions exist between the DNA binding domains of SRF and retinoic acid and retinoid X receptors. We further demonstrate that the repression may involve retinoid-dependent competition for a limiting amount of SRC-1 and p300 between SRF and retinoid receptors. We propose that the well-defined anti-proliferative action of retinoids could, at least in part, result from this novel transrepressive action on the mitogenic transcription factor SRF.