Cooperative Armoring of CAR and TCR T Cells by T Cell-Restricted IL15 and IL21 Universally Enhances Solid Tumor Efficacy

PURPOSE

Chimeric antigen receptor (CAR) and T-cell receptor (TCR) T-cell therapies are effective in a subset of patients with solid tumors, but new approaches are needed to universally improve patient outcomes. Here, we developed a technology to leverage the cooperative effects of IL15 and IL21, two common cytokine-receptor gamma chain family members with distinct, pleiotropic effects on T cells and other lymphocytes, to enhance the efficacy of adoptive T cells.

EXPERIMENTAL DESIGN

We designed vectors that induce the constitutive expression of either membrane-tethered IL15, IL21, or IL15/IL21. We used clinically relevant preclinical models of transgenic CARs and TCRs against pediatric and adult solid tumors to determine the effect of the membrane-tethered cytokines on engineered T cells for human administration.

RESULTS

We found that self-delivery of these cytokines by CAR or TCR T cells prevents functional exhaustion by repeated stimulation and limits the emergence of dysfunctional natural killer (NK)-like T cells. Across different preclinical murine solid tumor models, we observed enhanced regression with each individual cytokine but the greatest antitumor efficacy when T cells were armored with both.

CONCLUSIONS

The coexpression of membrane-tethered IL15 and IL21 represents a technology to enhance the resilience and function of engineered T cells against solid tumors and could be applicable to multiple therapy platforms and diseases. See related commentary by Ruffin et al., p. 1431.

Topoisomerases as anticancer targets

Many cancer type-specific anticancer agents have been developed and significant advances have been made toward precision medicine in cancer treatment. However, traditional or nonspecific anticancer drugs are still important for the treatment of many cancer patients whose cancers either do not respond to or have developed resistance to cancer-specific anticancer agents. DNA topoisomerases, especially type IIA topoisomerases, are proved therapeutic targets of anticancer and antibacterial drugs. Clinically successful topoisomerase-targeting anticancer drugs act through topoisomerase poisoning, which leads to replication fork arrest and double-strand break formation. Unfortunately, this unique mode of action is associated with the development of secondary cancers and cardiotoxicity. Structures of topoisomerase-drug-DNA ternary complexes have revealed the exact binding sites and mechanisms of topoisomerase poisons. Recent advances in the field have suggested a possibility of designing isoform-specific human topoisomerase II poisons, which may be developed as safer anticancer drugs. It may also be possible to design catalytic inhibitors of topoisomerases by targeting certain inactive conformations of these enzymes. Furthermore, identification of various new bacterial topoisomerase inhibitors and regulatory proteins may inspire the discovery of novel human topoisomerase inhibitors. Thus, topoisomerases remain as important therapeutic targets of anticancer agents.

Single-transducer dual-frequency ultrasound generation to enhance acoustic cavitation

Dual- or multiple-frequency ultrasound stimulation is capable of effectively enhancing the acoustic cavitation effect over single-frequency ultrasound. Potential application of this sonoreactor design has been widely proposed such as on sonoluminescence, sonochemistry enhancement, and transdermal drug release enhancement. All currently available sonoreactor designs employed multiple piezoelectric transducers for generating single-frequency ultrasonic waves separately and then these waves were mixed and interfered in solutions. The purpose of this research is to propose a novel design of generating dual-frequency ultrasonic waves with single piezoelectric elements, thereby enhancing acoustic cavitation. Macroscopic bubbles were detected optically, and they were quantified at either a single-frequency or for different frequency combinations for determining their efficiency for enhancing acoustic cavitation. Visible bubbles were optically detected and hydrogen peroxide was measured to quantify acoustic cavitation. Test water samples with different gas concentrations and different power levels were used to determine the efficacy of enhancing acoustic cavitation of this design. The spectrum obtained from the backscattered signals was also recorded and examined to confirm the occurrence of stable cavitation. The results confirmed that single-element dual-frequency ultrasound stimulation can enhance acoustic cavitation. Under certain testing conditions, the generation of bubbles can be enhanced up to a level of five times higher than the generation of bubbles in single-frequency stimulation, and can increase the hydrogen peroxide production up to an increase of one fold. This design may serve as a useful alternative for future sonoreactor design owing to its simplicity to produce dual- or multiple-frequency ultrasound.

Image display for collision avoidance of radiation therapy: treatment planning

Patient treatment in a medical linear accelerator is characterized by many angular and translational movements of the gantry and couch. The direction and orientation of each treatment beam is specified by a set of gantry, turntable, and collimator angles. It is possible that some selected treatment field configurations will result in gantry/couch or gantry/patient collisions that remain undetected during the treatment planning process. In this work, a digital camera has been used to record all the workable gantry/ patient set-up images, and a Windows programming language is used to edit and display these images on a personal computer for the treatment planner to screen the treatment plans. These graphical displays enable the planner to be aware of any potential collision hazards by an actual visualization of each selected gantry/turntable or gantry/patient angle configuration.

Correlates of financial satisfaction

The objectives of this study are to 1) assess the effects of major correlates of global subjective well-being on financial satisfaction, and 2) use empirical data to present the consequences of violating basic regression assumptions. Analyzing data from the General Social Surveys, 1972-1996 (Davis & Smith, 1996a) this study found that among Americans age forty-five and above, most of the major correlates of global subjective well-being show similar effects on financial satisfaction. The study's findings confirm a nonlinear effect of income on financial satisfaction. Comparing results from different analytical methods, this study also alerts researchers to the importance of taking into account the level of measurements of study variables, which have tended to be overlooked by previous subjective well-being research.

Impaired abdominal wall development and deficient wound healing in mice lacking aortic carboxypeptidase-like protein

Aortic carboxypeptidase-like protein (ACLP) is a member of a diverse group of proteins that contain a domain with similarity to that of the Dictyostelium discoideum protein discoidin I. The discoidin domain has been identified in mammalian milk fat globule membrane proteins, blood coagulation factors, and receptor tyrosine kinases, where it may facilitate cell aggregation, adhesion, or cell-cell recognition. Here we show that ACLP is a secreted protein that associates with the extracellular matrix (ECM). During mouse embryogenesis, ACLP is abundantly expressed in the ECM of collagen-rich tissues, including the vasculature, dermis, and the developing skeleton. We deleted the ACLP gene in mice by homologous recombination. The majority of ACLP(-/-) mice die perinatally due to gastroschisis, a severe disruption of the anterior abdominal wall and herniation of the abdominal organs. ACLP(-/-) mice that survived to adulthood developed nonhealing skin wounds. Following injury by a dermal punch biopsy, ACLP(-/-) mice exhibited deficient wound healing compared with controls. In addition, dermal fibroblasts isolated from ACLP(-/-) 18.5-day-postconception embryos exhibited a reduced proliferative capacity compared with wild-type cells. These results indicate that ACLP is an ECM protein that is essential for embryonic development and dermal wound healing processes.

Targeted expression of heme oxygenase-1 prevents the pulmonary inflammatory and vascular responses to hypoxia

Chronic hypoxia causes pulmonary hypertension with smooth muscle cell proliferation and matrix deposition in the wall of the pulmonary arterioles. We demonstrate here that hypoxia also induces a pronounced inflammation in the lung before the structural changes of the vessel wall. The proinflammatory action of hypoxia is mediated by the induction of distinct cytokines and chemokines and is independent of tumor necrosis factor-alpha signaling. We have previously proposed a crucial role for heme oxygenase-1 (HO-1) in protecting cardiomyocytes from hypoxic stress, and potent anti-inflammatory properties of HO-1 have been reported in models of tissue injury. We thus established transgenic mice that constitutively express HO-1 in the lung and exposed them to chronic hypoxia. HO-1 transgenic mice were protected from the development of both pulmonary inflammation as well as hypertension and vessel wall hypertrophy induced by hypoxia. Significantly, the hypoxic induction of proinflammatory cytokines and chemokines was suppressed in HO-1 transgenic mice. Our findings suggest an important protective function of enzymatic products of HO-1 activity as inhibitors of hypoxia-induced vasoconstrictive and proinflammatory pathways.

Akt participation in the Wnt signaling pathway through Dishevelled

Inactivation of glycogen synthase kinase 3beta (GSK3beta) and the resulting stabilization of free beta-catenin are critical steps in the activation of Wnt target genes. While Akt regulates GSK3alpha/beta in the phosphatidylinositide 3-OH kinase signaling pathway, its role in Wnt signaling is unknown. Here we report that expression of Wnt or Dishevelled (Dvl) increased Akt activity. Activated Akt bound to the Axin-GSK3beta complex in the presence of Dvl, phosphorylated GSK3beta and increased free beta-catenin levels. Furthermore, in Wnt-overexpressing PC12 cells, dominant-negative Akt decreased free beta-catenin and derepressed nerve growth factor-induced differentiation. Therefore, Akt acts in association with Dvl as an important regulator of the Wnt signaling pathway.

Trends in financial satisfaction among middle-age and old-age Americans, 1972-1996

Using data from the General Social Surveys (1972-1996), this study decomposes the trends in financial satisfaction into intercohort and intracohort patterns to assess the intracohort change and cohort replacement effects on financial satisfaction. The results suggest that a positive intracohort component of financial satisfaction trends, indicating more financial satisfaction with time; and a negative intercohort component, indicating that younger cohorts are less satisfied financially. The multivariate analysis further suggests that the change in financial satisfaction trends is mostly due to a strong intercohort replacement effect. That is, the change in financial satisfaction trends can be largely accounted for by the intercohort replacement effect of younger cohorts' being less satisfied financially.

CLIF, a novel cycle-like factor, regulates the circadian oscillation of plasminogen activator inhibitor-1 gene expression

The onset of myocardial infarction occurs frequently in the early morning, and it may partly result from circadian variation of fibrinolytic activity. Plasminogen activator inhibitor-1 activity shows a circadian oscillation and may account for the morning onset of myocardial infarction. However, the molecular mechanisms regulating this circadian oscillation remain unknown. Recent evidence indicates that basic helix-loop-helix (bHLH)/PAS domain transcription factors play a crucial role in controlling the biological clock that controls circadian rhythm. We isolated a novel bHLH/PAS protein, cycle-like factor (CLIF) from human umbilical vein endothelial cells. CLIF shares high homology with Drosophila CYCLE, one of the essential transcriptional regulators of circadian rhythm. CLIF is expressed in endothelial cells and neurons in the brain, including the suprachiasmatic nucleus, the center of the circadian clock. In endothelial cells, CLIF forms a heterodimer with CLOCK and up-regulates the PAI-1 gene through E-box sites. Furthermore, Period2 and Cryptochrome1, whose expression show a circadian oscillation in peripheral tissues, inhibit the PAI-1 promoter activation by the CLOCK:CLIF heterodimer. These results suggest that CLIF regulates the circadian oscillation of PAI-1 gene expression in endothelial cells. In addition, the results potentially provide a molecular basis for the morning onset of myocardial infarction.

Striated muscle preferentially expressed genes alpha and beta are two serine/threonine protein kinases derived from the same gene as the aortic preferentially expressed gene-1

Aortic preferentially expressed gene (APEG)-1 is a 1.4-kilobase pair (kb) mRNA expressed in vascular smooth muscle cells and is down-regulated by vascular injury. An APEG-1 5'-end cDNA probe identified three additional isoforms. The 9-kb striated preferentially expressed gene (SPEG)alpha and the 11-kb SPEGbeta were found in skeletal muscle and heart. The 4-kb brain preferentially expressed gene was detected in the brain and aorta. We report here cloning of the 11-kb SPEGbeta cDNA. SPEGbeta encodes a 355-kDa protein that contains two serine/threonine kinase domains and is homologous to proteins of the myosin light chain kinase family. At least one kinase domain is active and capable of autophosphorylation. In the genome, all four isoforms share the middle three of the five exons of APEG-1, and they differ from each other by using different 5'- and 3'-ends and alternative splicing. We show that the expression of SPEGalpha and SPEGbeta is developmentally regulated in the striated muscle during C2C12 myoblast to myotube differentiation in vitro and cardiomyocyte maturation in vivo. This developmental regulation suggests that both SPEGalpha and SPEGbeta can serve as sensitive markers for striated muscle differentiation and that they may be important for adult striated muscle function.

Thioredoxin facilitates the induction of heme oxygenase-1 in response to inflammatory mediators

Heme oxygenase (HO)-1 is a stress response protein that is regulated by oxidative stress. HO-1 catalyzes the generation of biliverdin, carbon monoxide, and iron from heme. Lipopolysaccharide (LPS) and interleukin (IL)-1beta induce HO-1 through the binding of nuclear proteins to AP-1 motifs in enhancer regions upstream from the transcription start site. The DNA binding activity of AP-1 proteins depends on the reduction of cysteines in their DNA-binding domains. We found that agents that disrupt free sulfhydryl groups abolish AP-1 binding activity in nuclear proteins obtained from rat aortic smooth muscle cells and macrophages stimulated with IL-1beta or LPS. Thioredoxin (TRX) may regulate the redox status of nuclear transcription factors in response to oxidative stimuli, thus we determined the role of TRX in the physiologic regulation of HO-1. TRX underwent nuclear translocation in cells stimulated with IL-1beta and LPS. We transfected macrophages with a heterologous promoter construct containing two AP-1 sites from an upstream enhancer region in the HO-1 promoter. Recombinant TRX induced promoter activity to a level analogous to that induced by LPS, and this TRX response was abolished by mutation of the AP-1 sites. An inhibitor of TRX reductase, used to prevent TRX translocation in the reduced state, decreased HO-1 induction by IL-1beta and LPS. These data provide the first evidence that TRX contributes to the induction of HO-1 by inflammatory mediators.

Prevention of hypoxia-induced pulmonary hypertension by enhancement of endogenous heme oxygenase-1 in the rat

We investigated the role of heme oxygenase (HO)-1 in the development of hypoxia-induced pulmonary hypertension. HO catalyzes the breakdown of heme to the antioxidant bilirubin and the vasodilator carbon monoxide. Hypoxia is a potent but transient inducer of HO-1 in vascular smooth muscle cells in vitro and in the lung in vivo. By using agonists of HO-1, we sustained a high expression of HO-1 in the lungs of rats for 1 week. We report that this in vivo enhancement of HO-1 in the lung prevented the development of hypoxic pulmonary hypertension and inhibited the structural remodeling of the pulmonary vessels. The mechanism(s) underlying this effect may involve a direct vasodilating and antiproliferative action of endogenous carbon monoxide, as well as an indirect effect of carbon monoxide on the production of vasoconstrictors. These results provide evidence that enhancement of endogenous adaptive responses may be used to prevent hypoxia-induced pulmonary hypertension.

Cardiovascular basic helix loop helix factor 1, a novel transcriptional repressor expressed preferentially in the developing and adult cardiovascular system

We have cloned a cardiovascular-restricted basic helix-loop-helix factor that interacts with arylhydrocarbon receptor nuclear translocator (ARNT) in a yeast two-hybrid screen. Cardiovascular helix-loop-helix factor 1 (CHF1) is distantly related to the hairy family of transcriptional repressors. We analyzed its expression pattern during mouse embryo development. At day 8.5, the expression of CHF1 is first detected in the primitive ventricle of the primordial heart tube and persists throughout gestation. In rat hearts, this expression is down-regulated after birth, concurrent with terminal differentiation of cardiomyocytes. In the developing vasculature, CHF1 first appears in the dorsal aorta at day 9.0, which precedes the reported expression of smooth muscle cell markers, and persists into adulthood. In an in vitro system of smooth muscle cell differentiation, CHF1 mRNA was barely detectable in undifferentiated cells but was induced highly in differentiated smooth muscle cells. To determine whether CHF1 might affect the function of ARNT, we performed transfection studies. Co-transfection of CHF1 inhibited ARNT/EPAS1-dependent transcription by 85%, and this inhibition is dose-dependent. In electrophoretic mobility studies, CHF1 inhibited the binding of the ARNT/EPAS1 heterodimer to its target site. Our data suggest that CHF1 functions as a transcriptional repressor and may play an important role in cardiovascular development.

Induction of high mobility group I architectural transcription factors in proliferating vascular smooth muscle in vivo and in vitro

Proliferation of vascular smooth muscle cells (VSMCs) is a hallmark of arteriosclerosis. Architectural transcription factors of the high mobility group (HMG)-I family have been implicated in the control of cell proliferation and gene expression. We studied the pattern of HMG-I mRNA and protein expression in proliferating VSMCs. HMG-I(Y) and HMGI-C mRNAs were barely detectable by Northern analysis in samples prepared from uninjured rat carotid arteries. In contrast, these mRNAs were induced dramatically in carotid arteries 2 and 5-6 days after balloon injury. By in situ hybridization at 6 days after injury, the induced mRNAs localized to smooth muscle cells of the developing neointima, and immunocytochemical analysis showed that HMG-I(Y) protein was expressed in the nuclei of these cells. To confirm this association between HMG-I protein induction and cell growth, we assessed HMG-I(Y) and HMGI-C mRNA expression in rat aortic smooth muscle cells (RASMCs) in primary culture. The HMG-I mRNAs were barely detectable in quiescent RASMCs but were induced markedly by serum stimulation. This induction of mRNA by serum was time dependent and peaked at 9 h. Western blot analysis confirmed that HMG-I(Y) protein induction also occurred in vitro. To our knowledge, this is the first demonstration of induction of HMG-I protein expression in proliferating RASMCs in vivo and in vitro. This demonstration suggests that the HMG-I proteins may play an important role in smooth muscle cell proliferation.

Genetic variation at nine STR loci in populations from the Philippines and Thailand living in Taiwan

In order to apply a set of nine STR loci and the amelogenin locus in forensic testing, we have performed a population study on individuals from the Philippines and Thailand living in Taiwan (273 Philippine and 146 Thai individuals were typed by commercially available kits and an automated sequencer). A total of 73 alleles for all systems for both populations could be observed in these two populations. No new intermediate fragments were found. Allele frequencies showed no deviation from Hardy-Weinberg equilibrium. The mean exclusion power (MEP) ranged from 0.327 (TPOX) to 0.706 (FGA), the discriminating power (DP) ranged from 0.790 (TPOX) to 0.963 (FGA) for Philippinos, MEP ranged from 0.247 (TPOX) to 0.723 (FGA), DP ranged from 0.761 (TPOX) to 0.968 (FGA) for Thais, the combined MEP is > 0.9988 and the combined DP is > 0.9999999993 for both Philippinos and Thais.

Generation of a dominant-negative mutant of endothelial PAS domain protein 1 by deletion of a potent C-terminal transactivation domain

Endothelial PAS domain protein 1 (EPAS1) is a basic helix-loop-helix/PAS domain transcription factor that is preferentially expressed in vascular endothelial cells. EPAS1 shares high homology with hypoxia-inducible factor-1alpha (HIF-1alpha) and, like HIF-1alpha, has been shown to bind to the HIF-1-binding site and to activate its downstream genes such as vascular endothelial growth factor (VEGF) and erythropoietin. In this report, we show that EPAS1 increased VEGF gene expression through the HIF-1-binding site. This transactivation was enhanced further by cotransfection of an aryl hydrocarbon receptor nuclear translocator expression plasmid. Deletion analysis of EPAS1 revealed a potent activation domain (amino acids 486-639) essential for EPAS1 to transactivate the VEGF promoter. We confirmed the ability of this domain to activate transcription using a Gal4 fusion protein system. Because a truncated EPAS1 protein lacking the transactivation domain at amino acids 486-639 eliminated induction of the VEGF promoter by wild-type EPAS1, the truncated protein functions as a dominant-negative mutant. Most important, infection of the cells with an adenoviral construct expressing this mutant inhibited the induction of VEGF mRNA under conditions that mimic hypoxia. Our results suggest that EPAS1 is an important regulator of VEGF gene expression. Since VEGF plays a crucial role in angiogenesis, the ability of dominant-negative EPAS1 to inhibit VEGF promoter activity raises the possibility of a novel approach to inhibiting pathological angiogenesis.

Genomic cloning and promoter analysis of aortic preferentially expressed gene-1. Identification of a vascular smooth muscle-specific promoter mediated by an E box motif

Aortic preferentially expressed gene-1 (APEG-1) was originally identified as a 1.4-kilobase (kb) transcript preferentially expressed in differentiated vascular smooth muscle cells (VSMC). Its expression is markedly down-regulated in de-differentiated VSMC, suggesting a role for APEG-1 in VSMC differentiation. We have now determined that APEG-1 is a single-copy gene in the human, rat, and mouse genomes and have mapped human APEG-1 to chromosome 2q34. To study the molecular mechanisms regulating its expression, we characterized the genomic organization and promoter of mouse APEG-1. APEG-1 spans 4.5 kb in the mouse genome and is composed of five exons. Using reporter gene transfection analysis, we found that a 2. 7-kb APEG-1 5'-flanking sequence directed a high level of promoter activity only in VSMC. Its activity was minimal in five other cell types. A repressor region located within an upstream 685-base pair sequence suppressed the activity of this 2.7-kb promoter. Further deletion and mutation analyses identified an E box motif as a positive regulatory element, which was bound by nuclear protein prepared from VSMC. In conjunction with its flanking sequence, this E box motif confers VSMC-specific enhancer activity to a heterologous SV40 promoter. To our knowledge, this is the first demonstration of an E box motif that mediates gene expression restricted to VSMC.

Hypoxia induces severe right ventricular dilatation and infarction in heme oxygenase-1 null mice

Heme oxygenase (HO) catalyzes the oxidation of heme to generate carbon monoxide (CO) and bilirubin. CO increases cellular levels of cGMP, which regulates vascular tone and smooth muscle development. Bilirubin is a potent antioxidant. Hypoxia increases expression of the inducible HO isoform (HO-1) but not the constitutive isoform (HO-2). To determine whether HO-1 affects cellular adaptation to chronic hypoxia in vivo, we generated HO-1 null (HO-1(-/-)) mice and subjected them to hypoxia (10% oxygen) for five to seven weeks. Hypoxia caused similar increases in right ventricular systolic pressure in wild-type and HO-1(-/-) mice. Although ventricular weight increased in wild-type mice, the increase was greater in HO-1(-/-) mice. Similarly, the right ventricles were more dilated in HO-1(-/-) mice. After seven weeks of hypoxia, only HO-1(-/-) mice developed right ventricular infarcts with organized mural thrombi. No left ventricular infarcts were observed. Lipid peroxidation and oxidative damage occurred in right ventricular cardiomyocytes in HO-1(-/-), but not wild-type, mice. We also detected apoptotic cardiomyocytes surrounding areas of infarcted myocardium by terminal deoxynucleotide transferase-mediated dUTP nick end-labeling (TUNEL) assays. Our data suggest that in the absence of HO-1, cardiomyocytes have a maladaptive response to hypoxia and subsequent pulmonary hypertension. J.Clin. Invest. 103:R23-R29 (1999).

High mobility group-I(Y) protein facilitates nuclear factor-kappaB binding and transactivation of the inducible nitric-oxide synthase promoter/enhancer

Nitric oxide (NO), a free radical gas whose production is catalyzed by the enzyme NO synthase, participates in the regulation of multiple organ systems. The inducible isoform of NO synthase (iNOS) is transcriptionally up-regulated by inflammatory stimuli; a critical mediator of this process is nuclear factor (NF)-kappaB. Our objective was to determine which regulatory elements other than NF-kappaB binding sites are important for activation of the iNOS promoter/enhancer. We also wanted to identify transcription factors that may be functioning in conjunction with NF-kappaB (subunits p50 and p65) to drive iNOS transcription. Deletion analysis of the iNOS promoter/enhancer revealed that an AT-rich sequence (-61 to -54) downstream of the NF-kappaB site (-85 to -76) in the 5'-flanking sequence was important for iNOS induction by interleukin-1beta and endotoxin in vascular smooth muscle cells. This AT-rich sequence, corresponding to an octamer (Oct) binding site, bound the architectural transcription factor high mobility group (HMG)-I(Y) protein. Electrophoretic mobility shift assays showed that HMG-I(Y) and NF-kappaB subunit p50 bound to the iNOS promoter/enhancer to form a ternary complex. The formation of this complex required HMG-I(Y) binding at the Oct site. The location of an HMG-I(Y) binding site typically overlaps that of a recruited transcription factor. In the iNOS promoter/enhancer, however, HMG-I(Y) formed a complex with p50 while binding downstream of the NF-kappaB site. Furthermore, overexpression of HMG-I(Y) potentiated iNOS promoter/enhancer activity by p50 and p65 in transfection experiments, suggesting that HMG-I(Y) contributes to the transactivation of iNOS by NF-kappaB.

Induction of high mobility group-I(Y) protein by endotoxin and interleukin-1beta in vascular smooth muscle cells. Role in activation of inducible nitric oxide synthase

Nonhistone chromosomal proteins of the high mobility group (HMG) affect the transcriptional regulation of certain mammalian genes. For example, HMG-I(Y) controls cytokine-mediated promoters that require transcription factors, such as nuclear factor-kappaB, for maximal expression. Even though a great deal is known about how HMG-I(Y) facilitates expression of other genes, less is known about the regulation of HMG-I(Y) itself, especially in cells in primary culture. Therefore we investigated the effect of endotoxin and the cytokine interleukin-1beta on HMG-I(Y) expression in vascular smooth muscle cells. Induction of HMG-I(Y) peaked after 48 h of interleukin-1beta stimulation (6.2-fold) in cells in primary culture, and this increase in mRNA corresponded to an increase in HMG-I(Y) protein. Moreover, immunohistochemical staining revealed a dramatic increase in HMG-I(Y) protein expression in vascular smooth muscle cells after endotoxin stimulation in vivo. This increase in HMG-I(Y) expression (both in vitro and in vivo) mirrored an up-regulation of inducible nitric oxide synthase, a cytokine-responsive gene. The functional significance of this coinduction is underscored by our finding that HMG-I(Y) potentiated the response of inducible nitric oxide synthase to nuclear factor-kappaB transactivation. Taken together, these studies suggest that induction of HMG-I(Y), and subsequent transactivation of iNOS, may contribute to a reduction in vascular tone during endotoxemia and other systemic inflammatory processes.

Embryonic expression suggests an important role for CRP2/SmLIM in the developing cardiovascular system

Proteins of the LIM family are critical regulators of development and differentiation in various cell types. We have described the cloning of cysteine-rich protein 2/smooth muscle LIM protein (CRP2/SmLIM), a LIM-only protein expressed in differentiated vascular smooth muscle cells. As a first step toward understanding the potential functions of CRP2/SmLIM, we analyzed its expression after gastrulation in developing mice and compared the expression of CRP2/SmLIM with that of the other 2 members of the CRP subclass, CRP1 and CRP3/MLP. In situ hybridization in whole-mount and sectioned embryos showed that CRP2/SmLIM was expressed in the sinus venosus and the 2 cardiac chambers at embryonic day 9. Vascular expression of CRP2/SmLIM was first seen at embryonic day 10. At subsequent time points, CRP2/SmLIM expression decreased in the heart but remained high in the vasculature. CRP1 was expressed both in vascular and nonvascular tissues containing smooth muscle cells, whereas CRP3/MLP was expressed only in tissues containing striated muscle. These patterns of expression were maintained in the adult animal and suggest an important role for this gene family in the development of smooth and striated muscle.

Validity and reliability of the Leisure Assessment Inventory

The validity and reliability of the Leisure Assessment Inventory, a tool developed to measure leisure behavior as it applies to adults with mental retardation, was examined. Leisure behavior was assessed using four indexes: Leisure Activity Participation, Leisure Preference, Leisure Interest, and Leisure Constraints. The inventory was administered to 92 adults, ages 30 and older, with mild to moderate mental retardation. Two indexes (Leisure Activity Participation and Leisure Interest) demonstrated higher reliability from test to retest whereas the remaining two (Leisure Preference and Leisure Constraints) showed only moderate consistency. Overall findings provide evidence of the inventory's stability, consistency, convergent and discriminant validity, and construct validity.

Aortic carboxypeptidase-like protein, a novel protein with discoidin and carboxypeptidase-like domains, is up-regulated during vascular smooth muscle cell differentiation

Phenotypic modulation of vascular smooth muscle cells plays an important role in the pathogenesis of arteriosclerosis. In a screen of proteins expressed in human aortic smooth muscle cells, we identified a novel gene product designated aortic carboxypeptidase-like protein (ACLP). The approximately 4-kilobase human cDNA and its mouse homologue encode 1158 and 1128 amino acid proteins, respectively, that are 85% identical. ACLP is a nonnuclear protein that contains a signal peptide, a lysine- and proline-rich 11-amino acid repeating motif, a discoidin-like domain, and a C-terminal domain with 39% identity to carboxypeptidase E. By Western blot analysis and in situ hybridization, we detected abundant ACLP expression in the adult aorta. ACLP was expressed predominantly in the smooth muscle cells of the adult mouse aorta but not in the adventitia or in several other tissues. In cultured mouse aortic smooth muscle cells, ACLP mRNA and protein were up-regulated 2-3-fold after serum starvation. Using a recently developed neural crest cell to smooth muscle cell in vitro differentiation system, we found that ACLP mRNA and protein were not expressed in neural crest cells but were up-regulated dramatically with the differentiation of these cells. These results indicate that ACLP may play a role in differentiated vascular smooth muscle cells.

Molecular cloning, characterization, and promoter analysis of the mouse Crp2/SmLim gene. Preferential expression of its promoter in the vascular smooth muscle cells of transgenic mice

Several members of the LIM protein family have important roles in development and differentiation. We recently isolated a rat cDNA encoding a new member of this family, CRP2/SmLIM, that contains two LIM domains and is expressed preferentially in vascular smooth muscle cells (VSMC). To study the molecular mechanisms that regulate VSMC-specific transcription of the Crp2/SmLim gene, we cloned the cDNA and gene of mouse Crp2/SmLim. Mouse Crp2/SmLim is a single copy gene of six exons and five introns spanning approximately 20 kilobases of genomic DNA. By 5'-rapid amplification of cDNA ends and S1 nuclease protection assay, we determined that the transcription start site is an A residue 80 base pairs 5' of the translation initiation codon. A TATA-like sequence is located 27 base pairs 5' of the transcription start site, and there are potential cis-acting elements (GATA, Sp1, AP-2, E box, CCAC box, and GArC motif) in the 5'-flanking sequence. In transient transfection assays in rat aortic smooth muscle cells in primary culture, 5 kilobases of the Crp2/SmLim 5'-flanking sequence generated a high level of luciferase reporter gene activity. By deletion analysis and gel mobility shift assay, we found that the region between bases -74 and -39 of this 5 kilobase DNA fragment binds Sp1 and confers basal promoter activity in the Crp2/SmLim gene. In vitro, the 5-kilobase fragment was active in multiple cell types. In vivo, however, the 5-kilobase fragment directed high level expression of the lacZ reporter gene preferentially in the VSMC of transgenic mice, indicating the presence of VSMC-specific element(s) in this fragment.

In vitro system for differentiating pluripotent neural crest cells into smooth muscle cells

The change in vascular smooth muscle cells (SMC) from a differentiated to a dedifferentiated state is the critical phenotypic response that promotes occlusive arteriosclerotic disease. Despite its importance, research into molecular mechanisms regulating smooth muscle differentiation has been hindered by the lack of an in vitro cell differentiation system. We identified culture conditions that promote efficient differentiation of Monc-1 pluripotent neural crest cells into SMC. Exclusive Monc-1 to SMC differentiation was indicated by cellular morphology and time-dependent induction of the SMC markers smooth muscle alpha-actin, smooth muscle myosin heavy chain, calponin, SM22alpha, and APEG-1. The activity of the SM22alpha promoter was low in Monc-1 cells. Differentiation of these cells into SMC caused a 20-30-fold increase in the activity of the wild-type SM22alpha promoter and that of a hybrid promoter containing three copies of the CArG element. By gel mobility shift analysis, we identified new DNA-protein complexes in nuclear extracts prepared from differentiated Monc-1 cells. One of the new complexes contained serum response factor. This Monc-1 to SMC model should facilitate the identification of nodal regulators of smooth muscle development and differentiation.

Human EZF, a Krüppel-like zinc finger protein, is expressed in vascular endothelial cells and contains transcriptional activation and repression domains

Members of the erythroid Krüppel-like factor (EKLF) multigene family contain three C-terminal zinc fingers, and they are typically expressed in a limited number of tissues. EKLF, the founding member, transactivates the beta-globin promoter by binding to the CACCC motif. EKLF is essential for expression of the beta-globin gene as demonstrated by gene deletion experiments in mice. Using a DNA probe from the zinc finger region of EKLF, we cloned a cDNA encoding a member of this family from a human vascular endothelial cell cDNA library. Sequence analysis indicated that our clone, hEZF, is the human homologue of the recently reported mouse EZF and GKLF. hEZF is a single-copy gene that maps to chromosome 9q31. By gel mobility shift analysis, purified recombinant hEZF protein bound specifically to a probe containing the CACCC core sequence. In co-transfection experiments, we found that sense but not antisense hEZF decreased the activity of a reporter plasmid containing the CACCC sequence upstream of the thymidine kinase promoter by 6-fold. In contrast, EKLF increased the activity of the reporter plasmid by 3-fold. By fusing hEZF to the DNA-binding domain of GAL4, we mapped a repression domain in hEZF to amino acids 181-388. We also found that amino acids 91-117 of hEZF confer an activation function on the GAL4 DNA-binding domain.

Down-regulation of the cyclin A promoter by transforming growth factor-beta1 is associated with a reduction in phosphorylated activating transcription factor-1 and cyclic AMP-responsive element-binding protein

Transforming growth factor (TGF)-beta1 prevents cell cycle progression by inhibiting several regulators, including cyclin A. To study the mechanisms by which TGF-beta1 down-regulates cyclin A gene expression, we transfected reporter plasmids driven by the cyclin A promoter into mink lung epithelial cells in the absence and presence of TGF-beta1. The TGF-beta1-induced down-regulation of cyclin A promoter activity appeared to be mediated via the activating transcription factor (ATF) site, because mutation of this site abolished down-regulation. Surprisingly, although TGF-beta1 treatment for 24 h markedly decreased cyclin A promoter activity, it did not decrease the abundance of the ATF-binding proteins ATF-1 and cyclic AMP-responsive binding protein (CREB). However, we detected 90 and 78% reductions (by Western analysis) in phosphorylated CREB and ATF-1, respectively, in mink lung epithelial cells treated with TGF-beta1. TGF-beta1-induced down-regulation of cyclin A promoter activity was reversed by okadaic acid (a phosphatase inhibitor) and by cotransfection with plasmids expressing the cAMP-dependent protein kinase catalytic subunit or the simian virus small tumor antigen (Sm-t, an inhibitor of PP2A). These data indicate that TGF-beta1 may down-regulate cyclin A promoter activity by decreasing phosphorylation of CREB and ATF-1.

Collagen VIII is expressed by vascular smooth muscle cells in response to vascular injury

To identify genes involved in vascular remodeling, we applied differential mRNA display analysis to the rat carotid artery balloon injury model. One polymerase chain reaction product showing increased expression at days 2 to 14 after vascular injury was nearly identical to the mouse alpha 1 chain of type VIII collagen, a heterotrimeric short-chain collagen of uncertain function expressed by a limited number of cell types. By Northern analysis, expression of both chains of the type VIII collagen heterotrimer increased: collagen alpha 1 (VIII) mRNA expression was almost 4-fold higher than control by 7 days after vascular injury, and collagen alpha 2 (VIII) mRNA expression reached a maximum of almost 6-fold above baseline by 3 days after injury. By immunohistochemical analysis, type VIII collagen expression increased in the media and neointima in a localized pattern consistent with the distribution of activated dedifferentiated vascular smooth muscle cells (VSMCs). Cultured VSMCs expressed higher levels of type VIII collagen in response to serum and growth factors, notably platelet-derived growth factor (PDGF)-BB. VSMCs adhered significantly less to type VIII collagen than to type I collagen substrata and showed greater PDGF-BB-stimulated migration (by 2.2-fold) on type VIII collagen than on type I collagen. We hypothesize that increased expression of type VIII collagen by VSMCs after arterial injury may contribute to vascular remodeling through the promotion of VSMC migration.

Induction of heme oxygenase-1 expression in vascular smooth muscle cells. A link to endotoxic shock

Endotoxic shock is a life-threatening consequence of severe Gram-negative infection characterized by vascular smooth muscle cell relaxation and severe hypotension. The production of nitric oxide (NO), through the inducible NO synthase pathway, has been implicated as a major contributor in this process. We now demonstrate that heme oxygenase (HO), an enzyme that generates carbon monoxide (CO) in the course of heme metabolism, may also be involved in the hemodynamic compromise of endotoxic shock. Inducible HO (HO-1) mRNA levels are dramatically increased in aortic tissue from rats receiving endotoxin, and this increase in vascular HO-1 message is associated with an 8.9-fold increase in HO enzyme activity in vivo. Immunocytochemical staining localizes an increase in HO-1 protein within smooth muscle cells of both large (aorta) and small (arterioles) blood vessels. Furthermore, zinc protoporphyrin IX, an inhibitor of HO activity, abrogates endotoxin-induced hypotension in rats. Studies performed in rat vascular smooth muscle cells in vitro show that the induction of HO-1 mRNA is regulated at the level of gene transcription, and this induction is independent of NO production. Taken together, these studies suggest that the up-regulation of HO-1, and the subsequent production of CO, contributes to the reduction in vascular tone during endotoxic shock.

Degradation of E2A proteins through a ubiquitin-conjugating enzyme, UbcE2A

The helix-loop-helix E2A proteins (E12 and E47) govern cellular growth and differentiation. To identify binding partners that regulate the function of these ubiquitous transcription factors, we screened for proteins that interacted with the C terminus of E12 by the yeast interaction trap. UbcE2A, a rat enzyme that is highly homologous to and functionally complements the yeast ubiquitin-conjugating enzyme UBC9, was identified and cloned. UbcE2A appears to be an E2A-selective ubiquitin-conjugating enzyme because it interacts specifically with a 54-amino acid region in E47-(477-530) distinct from the helix-loop-helix domain. In contrast, most of the UbcE2A protein is required for interaction with an E2A protein. The E2A proteins appear to be degraded by the ubiquitin-proteasome pathway because the E12 half-life of 60 min is extended by the proteasome inhibitor MG132, and E12 is multi-ubiquitinated in vivo. Finally, antisense UbcE2A reduces E12 degradation. By participating in the degradation of the E2A proteins, UbcE2A may regulate cell growth and differentiation.

APEG-1, a novel gene preferentially expressed in aortic smooth muscle cells, is down-regulated by vascular injury

Despite the importance of phenotypic alterations in arterial smooth muscle cells (ASMC) during the pathogenesis of arteriosclerosis, little is known about genes that define differentiated ASMC. Using differential mRNA display, we isolated a novel gene preferentially expressed in the rat aorta and termed this gene APEG-1. The cDNA of rat APEG-1 contained an open reading frame encoding 113 amino acids, which would predict a basic protein of 12.7 kDa. The amino acid sequence of rat APEG-1 was highly conserved among human and mouse homologues (97 and 98%, respectively). Using an APEG-1 fusion protein containing an N-terminal c-Myc tag, we identified APEG-1 as a nuclear protein. By in situ hybridization, APEG-1 mRNA was expressed in rat ASMC. Although APEG-1 was expressed highly in differentiated ASMC in vivo, its expression was quickly down-regulated and disappeared in dedifferentiated ASMC in culture. In vivo, APEG-1 mRNA levels decreased by more than 80% in response to vascular injury as ASMC changed from a quiescent to a proliferative phenotype. Taken together, these data indicate that APEG-1 is a novel marker for differentiated ASMC and may have a role in regulating growth and differentiation of this cell type.

Induction of apoptosis by pyrrolidinedithiocarbamate and N-acetylcysteine in vascular smooth muscle cells

Pyrrolidinedithiocarbamate (PDTC) and N-acetylcysteine (NAC) have been used as antioxidants to prevent apoptosis in lymphocytes, neurons, and vascular endothelial cells. We report here that PDTC and NAC induce apoptosis in rat and human smooth muscle cells. In rat aortic smooth muscle cells, PDTC induced cell shrinkage, chromatin condensation, and DNA strand breaks consistent with apoptosis. In addition, overexpression of Bcl-2 suppressed vascular smooth muscle cell death caused by PDTC and NAC. The viability of rat aortic smooth muscle cells decreased within 3 h of treatment with PDTC and was reduced to 30% at 12 h. The effect of PDTC and NAC on smooth muscle cells was not species specific because PDTC and NAC both caused dose-dependent reductions in viability in rat and human aortic smooth muscle cells. In contrast, neither PDTC nor NAC reduced viability in human aortic endothelial cells. The use of antioxidants to induce apoptosis in vascular smooth muscle cells may help prevent their proliferation in arteriosclerotic lesions.

Suppression of interleukin-1beta-induced nitric-oxide synthase promoter/enhancer activity by transforming growth factor-beta1 in vascular smooth muscle cells. Evidence for mechanisms other than NF-kappaB

Nitric-oxide synthases (NOS) utilize L-arginine to produce NO, a potent vasodilator that contributes to the regulation of vascular tone. We demonstrated previously that transforming growth factor (TGF)-beta1 down-regulates inducible NOS after its induction by interleukin (IL)-1beta by decreasing the rate of inducible NOS gene transcription. In the present study we transfected reporter plasmids containing various lengths of the inducible NOS 5'-flanking region into primary cultured rat aortic smooth muscle cells and stimulated the cells with IL-1beta or vehicle. IL-1beta increased the activity of the plasmid containing -1485 to +31 of the inducible NOS gene by more than 10-fold, indicating the presence of IL-1beta-responsive elements. Further deletion analysis revealed that a construct containing -234 to +31 of the inducible NOS gene contained the majority of promoter/enhancer activity after IL-1beta stimulation. Mutation of the NF-kappaB site within this region partially reduced IL-1beta-inducible activity; however, a large portion of activity remained independent of the NF-kappaB site. TGF-beta1 suppressed promoter/enhancer activity after IL-1beta stimulation, and this suppression was complete in the construct with a mutated NF-kappaB site. In addition, TGF-beta1 did not decrease the binding of nuclear proteins to the NF-kappaB site. These data suggest that the ability of TGF-beta1 to suppress inducible NOS promoter/enhancer activity occurs through a site(s) other than the NF-kappaB motif in vascular smooth muscle cells.

[The effect of RU486 on contractility of rabbit oviduct smooth muscle]

An investigation on the effect of RU486 on isolated ovicluct smooth muscle contraction of pseudopregant rabbits was carried out by using the mechanical-electrical transducer of Galson recorder. The results showed that: (1) RU486 acted directly on the oviduct smooth muscle by increasing contractile frequency, without changing tension and amplitude. This effect is similar to that found in the in vivo experiment. (2) RU486 partially inhibited Ca(2+)-induced smooth muscle contraction and also showed significant synergistic effect of Verapamil and antagonistic effect of NE on muscle contractility. However, RU486 is unable to exert any effect on Forskolin-stimulated contraction. Thus it appears that the RU486 effect on oviduct smooth muscle contraction is a result of affecting intracellular free calium, due possibly to interference of Ca2+ influx and/or endoplasmic reticulum Ca2+ release and Ca(2+)-Ip3 transducing mechanism.

Molecular cloning and characterization of SmLIM, a developmentally regulated LIM protein preferentially expressed in aortic smooth muscle cells

Differentiated, quiescent vascular smooth muscle cells assume a dedifferentiated, proliferative phenotype in response to injury, one of the hallmarks of arteriosclerosis. Members of the LIM family of zinc-finger proteins are important in the differentiation of various cells including striated muscle. We describe here the molecular cloning and characterization of a developmentally regulated smooth muscle LIM protein, SmLIM, that is expressed preferentially in the rat aorta. This 194-amino acid protein has two LIM domains, and comparisons of rat SmLIM with its mouse and human homologues reveal high levels of amino acid sequence conservation (100 and 99%, respectively). SmLIM is a nuclear protein and maps to human chromosome 3. SmLIM mRNA expression was high in aorta but not in striated muscle and low in other smooth muscle tissues such as intestine and uterus. In contrast with arterial tissue, SmLIM mRNA was barely detectable in venous tissue. The presence of SmLIM expression within aortic smooth muscle cells was confirmed by in situ hybridization. In vitro, SmLIM mRNA levels decreased by 80% in response to platelet-derived growth factor-BB in rat aortic smooth muscle cells. In vivo, SmLIM mRNA decreased by 60% in response to vessel wall injury during periods of maximal smooth muscle cell proliferation. The down-regulation of SmLIM by phenotypic change in vascular smooth muscle cells suggests that it may be involved in their growth and differentiation.

Arrest of endotoxin-induced hypotension by transforming growth factor beta1

Septic shock is a cytokine-mediated process typically caused by a severe underlying infection. Toxins generated by the infecting organism trigger a cascade of events leading to hypotension, to multiple organ system failure, and frequently to death. Beyond supportive care, no effective therapy is available for the treatment of septic shock. Nitric oxide (NO) is a potent vasodilator generated late in the sepsis pathway leading to hypotension; therefore, NO represents a potential target for therapy. We have previously demonstrated that transforming growth factor (TGF) beta1 inhibits inducible NO synthase (iNOS) mRNA and NO production in vascular smooth muscle cells after its induction by cytokines critical in the sepsis cascade. Thus, we hypothesized that TGF-beta1 may inhibit iNOS gene expression in vivo and be beneficial in the treatment of septic shock. In a conscious rat model of septic shock produced by Salmonella typhosa lipopolysaccharide (LPS), TGF-beta1 markedly reduced iNOS mRNA and protein levels in several organs. In contrast, TGF-beta1 did not decrease endothelium-derived constitutive NOS mRNA in organs of rats receiving LPS. We also performed studies in anesthetized rats to evaluate the effect of TGF-beta1 on the hemodynamic compromise of septic shock; after an initial 25% decrease in mean arterial pressure, TGF-beta1 arrested LPS-induced hypotension and decreased mortality. A decrease in iNOS mRNA and protein levels in vascular smooth muscle cells was demonstrated by in situ hybridization and NADPH diaphorase staining in rats treated with TGF-beta1. Thus these studies suggest that TGF-beta1 inhibits iNOS in vivo and that TGF-beta1 may be of future benefit in the therapy of septic shock.

Cloning and functional analysis of the promoter for KDR/flk-1, a receptor for vascular endothelial growth factor

KDR/flk-1 is one of two receptors for vascular endothelial growth factor, a potent angiogenic peptide. KDR/flk-1 is an early marker for endothelial cell progenitors, and its expression is restricted to endothelial cells in vivo. To investigate the molecular mechanisms regulating expression of KDR/flk-1, we cloned and characterized the promoter of the human KDR/flk-1 gene. The transcription start site was localized by primer extension and ribonuclease protection to a nucleotide 303 base pairs (bp) 5' of the initiation methionine codon. The 5'-flanking sequence is rich in G and C residues and contains five Sp1 elements but no TATA consensus sequence. By reporter gene transfection experiments, we found that approximately 4 kilobases of KDR/flk-1 5'-flanking sequence directed high level luciferase activity in bovine aortic endothelial cells; further deletion analysis revealed positive regulatory elements between bp -225 to -164, -95 to -77, -77 to -60, and +105 to +127. Mutation of an atypical GATA sequence between bp +105 and +127 did not affect promoter activity, suggesting that GATA elements are not essential for the high level promoter activity of this gene. Consistent with endothelial cell-restricted expression of KDR/flk-1 mRNA, we found that the 4-kilobase flanking sequence directed high level promoter activity in endothelial cells but not in other cell types. To our knowledge this is the first report characterizing the KDR/flk-1 promoter. Understanding the KDR/flk-1 promoter will allow us to investigate endothelial cell-specific gene regulation and to uncover methods for targeting gene delivery specifically to endothelial cells.

The ATF site mediates downregulation of the cyclin A gene during contact inhibition in vascular endothelial cells

Contact inhibition mediates monolayer formation and withdrawal from the cell cycle in vascular endothelial cells. In studying the cyclins--key regulators of the cell cycle--in bovine aortic endothelial cells (BAEC), we found that levels of cyclin A mRNA decreased in confluent BAEC despite the presence of 10% fetal calf serum. We then transfected into BAEC a series of plasmids containing various lengths of the human cyclin A 5' flanking sequence and the luciferase gene. Plasmids containing 3,200, 516, 406, 266, or 133 bp of the human cyclin A promoter directed high luciferase activity in growing but not confluent BAEC. In contrast, a plasmid containing 23 bp of the cyclin A promoter was associated with a 65-fold reduction in activity in growing BAEC, and the promoter activities of this plasmid were identical in both growing and confluent BAEC. Mutation of the activating transcription factor (ATF) consensus sequence at bp -80 to -73 of the cyclin A promoter decreased its activity, indicating the critical role of the ATF site. We identified by gel mobility shift analysis protein complexes that bound to the ATF site in nuclear extracts from growing but not confluent BAEC and identified (with antibodies) ATF-1 as a binding protein in nuclear extracts from growing cells. Also, ATF-1 mRNA levels decreased in confluent BAEC. Taken together, these data suggest that the ATF site and its cognate binding proteins play an important role in the downregulation of cyclin A gene expression during contact inhibition.

Disappearance of cyclin A correlates with permanent withdrawal of cardiomyocytes from the cell cycle in human and rat hearts

The regulated expression of cyclins controls the cell cycle. Because cardiomyocytes in adult mammals withdraw permanently from the cell cycle and thus cannot regenerate after injury, we examined cyclin expression during development by comparing cyclin A-E mRNA levels in fetal and adult human hearts. Cyclin B mRNA was detectable in adult hearts, although at a level markedly lower than that in fetal hearts. Levels of cyclin C, D1, D2, D3, and E mRNA were essentially identical in the two groups. In contrast, cyclin A mRNA was undetectable in adult hearts whereas cyclin A mRNA and protein were readily detectable in fetal hearts and cardiomyocytes, respectively. We then measured cyclin A mRNA and protein levels in rat hearts at four stages of development (fetal and 2, 14, and 28 d). Cyclin A mRNA and protein levels decreased quickly after birth (to 37% at day 2) and became undetectable within 14 d, an observation consistent with reports that cardiomyocytes stop replicating in rats by the second to third postnatal week. This disappearance of cyclin A gene expression in human and rat hearts at the time cardiomyocytes become terminally differentiated suggests that cyclin A downregulation is important in the permanent withdrawal of cardiomyocytes from the cell cycle.

Induction of vascular endothelial growth factor gene expression by interleukin-1 beta in rat aortic smooth muscle cells

Vascular endothelial growth factor (VEGF) is a potent and specific mitogen for vascular endothelial cells and promotes neovascularization in vivo. To determine whether interleukin-1 beta (IL-1 beta), which is present in atherosclerotic lesions, induces VEGF gene expression in vascular smooth muscle cells, we performed RNA blot analysis on rat aortic smooth muscle cells (RASMC) with a rat VEGF cDNA probe. IL-1 beta increased VEGF mRNA levels in RASMC in a time- and dose-dependent manner. As little as 0.1 ng/ml IL-1 beta increased VEGF mRNA levels by 2-fold and 10 ng/ml IL-1 beta increased VEGF mRNA by 4-fold. We also measured the half-life of VEGF mRNA and performed nuclear run-on experiments before and after addition of IL-1 beta to see if IL-1 beta increased VEGF mRNA levels by stabilizing the mRNA or by increasing its rate of transcription. The normal, 2-h half-life of VEGF mRNA in RASMC was lengthened to 3.2 h (60%) by IL-1 beta, and IL-1 beta increased the rate of VEGF gene transcription by 2.1-fold. In immunoblot experiments with an antibody specific for VEGF, we found that IL-1 beta increased VEGF protein levels in RASMC by 3.3-fold. Together these data indicate that IL-1 beta induces VEGF gene expression in smooth muscle cells. This IL-1 beta-induced expression of VEGF may accelerate the progression of atherosclerotic lesions by promoting the development of new blood vessels.

Tissue-specific expression of Ran isoforms in the mouse

Ran genes encode a family of well-conserve small nuclear GTPases (Ras-related nuclear proteins), whose function is implicated in both normal cell cycle progression and the transport of RNA and proteins between the nucleus and the cytoplasm. Previous studies of Ran proteins have utilized cell-free systems, yeasts, and cultured mammalian cells. We have now characterized patterns of Ran gene expression in the mouse. Serum starvation suppressed Ran gene transcription in mouse 3T3 cells. Ran mRNA reappeared in cells within 3 h after refeeding. A single Ran mRNA species was detected at low levels in most somatic tissues of the adult mouse. In testis, this Ran mRNA was abundant, as were other larger transcripts. Analysis of testis-derived Ran cDNA clones revealed the presence of two transcripts, one specifying an amino acid sequence identical to that of human Ran/TC4 and one specifying an amino acid sequence 94% identical. Northern blotting and reverse transcriptase-PCR assays with oligonucleotide probes and primers specific for each transcript demonstrated that the isoform identical to Ran/TC4 was expressed in both somatic tissues and testis, while the variant form was transcribed only in testis. The existence of tissue-specific Ran isoforms may help to rationalize the diverse roles suggested for Ran by previous biochemical studies.

Is child maltreatment a leading cause of delinquency?

This article explores the assumption that child maltreatment is a major cause of juvenile delinquency. Although this relationship is widely accepted as fact, the research that exists in the literature so far is inconclusive at best, and at worst, deeply flawed. For too long, juvenile justice resources have been channeled into the apprehension and processing of youthful offenders, while relatively few dollars have gone into the research necessary to formulate a coherent strategy for solving the juvenile crime problem. Without funding for this much-needed research, the money we do spend on the control and prevention of juvenile crime is blindly spent.

Promotion of vascular smooth muscle cell growth by homocysteine: a link to atherosclerosis

Plasma homocysteine levels are elevated in 20-30% of all patients with premature atherosclerosis. Although elevated homocysteine levels have been recognized as an independent risk factor for myocardial infarction and stroke, the mechanism by which these elevated levels cause atherosclerosis is unknown. To understand the role of homocysteine in the pathogenesis of atherosclerosis, we examined the effect of homocysteine on the growth of both vascular smooth muscle cells and endothelial cells at concentrations similar to those observed in clinical studies. As little as 0.1 mM homocysteine caused a 25% increase in DNA synthesis, and homocysteine at 1 mM increased DNA synthesis by 4.5-fold in rat aortic smooth muscle cells (RASMC). In contrast, homocysteine caused a dose-dependent decrease in DNA synthesis in human umbilical vein endothelial cells. Homocysteine increased mRNA levels of cyclin D1 and cyclin A in RASMC by 3- and 15-fold, respectively, indicating that homocysteine induced the mRNA of cyclins important for the reentry of quiescent RASMC into the cell cycle. Furthermore, homocysteine promoted proliferation of quiescent RASMC, an effect markedly amplified by 2% serum. The growth-promoting effect of homocysteine on vascular smooth muscle cells, together with its inhibitory effect on endothelial cell growth, represents an important mechanism to explain homocysteine-induced atherosclerosis.

Transforming growth factor-beta 1, but not dexamethasone, down-regulates nitric-oxide synthase mRNA after its induction by interleukin-1 beta in rat smooth muscle cells

Nitric oxide (NO), which accounts for the biologic properties of endothelium-derived relaxing factor, is synthesized from L-arginine by nitric-oxide synthase (NOS). Two classes of NOS have been identified: a constitutive, calcium-dependent isozyme (cNOS) and an inducible, calcium-independent isozyme (iNOS). NO is generated after the induction of iNOS by cytokines such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha. As a potent vasodilator, NO may have an important role in the severe hypotension of septic shock. We investigated whether dexamethasone and transforming growth factor-beta 1 (TGF-beta 1) suppress iNOS mRNA after its induction by IL-1 beta. We found that IL-1 beta induced iNOS mRNA in rat aortic smooth muscle cells (RASMC) in a dose- and time-dependent fashion. IL-1 beta promoted a dramatic and prolonged induction of RASMC iNOS mRNA that peaked at 48 h. Dexamethasone prevented this induction of iNOS mRNA only when given before the addition of IL-1 beta. In contrast, TGF-beta 1 inhibited the induction of iNOS mRNA and NO production in RASMC both before and after the addition of IL-1 beta. After 24 h of IL-1 beta stimulation, TGF-beta 1 down-regulated the iNOS mRNA that had been induced during this initial time period. In nuclear run-on experiments, we found that the down-regulation of iNOS mRNA by TGF-beta 1 in RASMC occurred at the transcriptional level. Our observation that TGF-beta 1 mediates inhibition of RASMC iNOS mRNA after its induction by cytokines may be an important insight into the treatment of septic shock.

Influence of temperature of flushing solution on lung preservation

For lung transplantation the technique of flushing the donor pulmonary vascular bed may provide advantages in lung preservation such as rapid cooling and washout of blood. However, rapid cooling of the ischemic lung may also produce adverse effects. The aim of this study was to compare methods of cold flushing and topical cooling, and to evaluate the effect of temperature of the flushing solution on lung preservation. A total of 25 rabbit lungs were studied. Using an ex vivo rabbit lung model, postischemic function was assessed by the ability of the lung to oxygenate perfused blood and by measurement of pulmonary artery and airway pressures. The lungs in group I were preserved with simple immersion at 10 degrees C for 30 hours. The lungs in groups II through V were flushed with solution containing phosphate-buffered dextran (LPD) at different temperatures (groups II and IV, 10 degrees C; groups III and V, 23 degrees C) and stored at 10 degrees C for various ischemic periods (groups II and III, 30 hours; groups IV and V, 36 hours). Pulmonary vascular resistance during flushing at 10 degrees C was significantly higher than that at 23 degrees C (p < 0.001). Flushing resulted in better preservation than topical hypothermia. Flushing at 23 degrees C resulted in superior postischemic function compared with flushing at 10 degrees C. We conclude that in lung preservation, uniform flushing with LPD solution improves the ischemic tolerance as compared with topical hypothermia, and that flushing with solutions at too low temperatures may have adverse effects on lung preservation.

Production and reversibility of right ventricular hypertrophy and right heart failure in dogs

Combined heart-lung transplantation has been used for end-stage primary pulmonary hypertension. Experience with single-lung transplantation for other conditions suggested that associated severe right ventricular dysfunction resulting from increased afterload would recover after placement of a satisfactory lung allograft. Early experience with the application of single-lung transplantation for pulmonary hypertension supports this contention. We devised a reversible canine model of chronic progressive pressure-overloaded right heart failure by pulmonary artery banding to study the echocardiographic, hemodynamic, and pathological reversibility of the failing right heart. Clinical right heart failure was defined as the development of ascites and pleural effusions. Right heart failure developed in 23 dogs 67 to 348 days after banding, and they were divided into two groups to determine its early and long-term effects. Group 1 dogs (n = 11) were either sacrificed immediately after the onset of right heart failure (n = 5) or unbanded (n = 6); group 2 dogs (n = 12) were maintained in right heart failure for 3 months and then either sacrificed (n = 6) or unbanded. Unbanded dogs in both groups were observed for 4 additional months before sacrifice. A control group of 6 normal dogs was sacrificed for pathological comparisons. After unbanding, the right ventricular systolic pressure fell from 97 +/- 17 mm Hg (group 1) and 88 +/- 31 mm Hg (group 2) to 44 +/- 11 mm Hg and 47 +/- 13 mm Hg, respectively. Despite this persistent gradient across the pulmonary artery, echocardiographic and hemodynamic measures of right ventricular function returned to normal, albeit more slowly in the group 2 dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma atrial natriuretic factor concentrations in a canine model of right heart pressure overload

Two studies were carried out in order to evaluate the plasma atrial natriuretic factor (ANF) concentrations, as well as hemodynamic and renal profiles in a chronic canine model of right heart pressure overload induced by pulmonary artery (PA) banding. In study I (n = 6), the animals were submitted to a gradual increase in pressure to clarify whether an increase in pressure or atrial distension was the main stimulus to ANF secretion. In study II (n = 6), right heart pressure overload was produced more rapidly, resulting in fluid retention and weight gain, thereby completing the model of right heart failure, and allowing an evaluation of the mechanisms involved in ANF resistance. In study I there were significant increases in right atrial pressure over baseline at 20 weeks, ANF levels at 24 weeks and right atrial area at 28 weeks following PA banding. In study II right heart pressures and ANF levels were higher than baseline at 12 weeks (p less than 0.0001), and fluid retention developed between 12-24 weeks in all dogs. The results suggest that increased right heart pressure, rather than atrial size, is a primary stimulus to ANF secretion in chronic right heart pressure overload. Despite the increases in right atrial pressure, clinical fluid retention occurred only with elevations of renin and aldosterone.