Receptor-targeted gene delivery using multivalent phagemid particles.

Although growth factor- and antibody-targeted filamentous phage have recently been demonstrated to transduce mammalian cells, there is a significant need to increase transduction efficiency so as to improve the usefulness of targeted phage vectors for gene therapy and ligand discovery. Here, we describe the use of multivalent phagemid vectors that are specifically designed for ligand-targeted mammalian cell transduction. This phagemid system has certain advantages over phage vectors, such as larger insert size and vector stability, and it retains the multivalent display necessary for efficient cell binding and internalization. Immunoblotting revealed that the most efficient multivalent display (exceeding that of a phage vector) was achieved in the phagemid system when epidermal growth factor (EGF) was fused to the C-terminal domain of the pIII coat protein. We compared phagemid particles displaying EGF at high or low valence by rescuing the vector with R408d3 (pIII deleted) or wild-type R408 helper phage, respectively. More efficient display of EGF correlated with increased internalization, vector potency, and transduction efficiency ( approximately 9%). The findings described here support our original hypothesis that phage-based vectors can be modified for more efficient gene transfer and suggest that directed evolution may be applied to increase their potential even further.

Genetic selection of phage engineered for receptor-mediated gene transfer to mammalian cells.

Although phage display is a powerful way of selecting ligands against purified target proteins, it is less effective for selecting functional ligands for complex targets like living cells. Accordingly, phage display has had limited utility in the development of targeting agents for gene therapy vectors. By adapting a filamentous bacteriophage for gene delivery to mammalian cells, however, we show here that it is possible to screen phage libraries for functional ligands capable of delivering DNA to cells. For example, when targeted with epidermal growth factor (EGF), M13 bacteriophage were capable of delivering a green fluorescent protein (GFP) gene to EGF receptor bearing cells in a ligand-, time-, and phage concentration-dependent manner. The EGF-targeted phage transduced COS-1 cells in a highly specific manner as demonstrated by competition with excess free EGF or alternatively with anti-EGF receptor antibodies. We further demonstrate that EGF-phage can be selected, by their ability to transduce EGF receptor bearing cells from libraries of peptide display phage. When phage were incubated with COS-1 cells, EGF ligand-encoding sequences were recovered by PCR from FACsorted, GFP-positive cells and the EGF-displaying phage were enriched 1 million-fold by four rounds of selection. These data suggest the feasibility of applying molecular evolution to phage gene delivery to select novel cell-specific DNA-targeting ligands. The same approach could be used to select genetically altered phage that are specifically designed and evolved as gene therapy vectors.

Cytoskeletal reorganization induced by engagement of the NG2 proteoglycan leads to cell spreading and migration.

Cells expressing the NG2 proteoglycan can attach, spread, and migrate on surfaces coated with NG2 mAbs, demonstrating that engagement of NG2 can trigger the cytoskeletal rearrangements necessary for changes in cell morphology and motility. Engagement of different epitopes of the proteoglycan results in distinct forms of actin reorganization. On mAb D120, the cells contain radial actin spikes characteristic of filopodial extension, whereas on mAb N143, the cells contain cortical actin bundles characteristic of lamellipodia. Cells that express NG2 variants lacking the transmembrane and cytoplasmic domains are unable to spread or migrate on NG2 mAb-coated surfaces, indicating that these portions of the molecule are essential for NG2-mediated signal transduction. Cells expressing an NG2 variant lacking the C-terminal half of the cytoplasmic domain can still spread normally on mAbs D120 and N143, suggesting that the membrane-proximal cytoplasmic segment is responsible for this process. In contrast, this variant migrates poorly on mAb D120 and exhibits abnormal arrays of radial actin filaments decorated with fascin during spreading on this mAb. The C-terminal portion of the NG2 cytoplasmic domain, therefore, may be involved in regulating molecular events that are crucial for cell motility.

High-affinity binding of basic fibroblast growth factor and platelet-derived growth factor-AA to the core protein of the NG2 proteoglycan.

NG2 is a transmembrane chondroitin sulfate proteoglycan that is expressed by immature progenitor cells in several developmental lineages and by some types of malignant cells. In vitro studies have suggested that NG2 participates in growth factor activation of the platelet-derived growth factor-alpha receptor. In this study the ability of recombinant NG2 core protein to interact with several different growth factors (epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF)-AA, PDGF-BB, vascular endothelial growth factor (VEGF)165 and transforming growth factor (TGF)-beta1) was investigated using two different assay systems: enzyme-linked immunosorbent assay-type solid-phase binding and an optical biosensor (BIAcore) system. High-affinity binding of bFGF and PDGF-AA to the core protein of NG2 could be demonstrated with both types of assays. Using both the BIAcore software analysis program and nonlinear regression analysis of the solid phase binding data, KD values in the low nanomolar range were obtained for binding of each of these growth factors to NG2. The results further indicate that NG2 contains at least two binding sites for each of these two growth factors. PDGF-BB, TGF-beta1, VEGF, and EGF exhibited little or no binding to NG2 in either type of assay. These data suggest that NG2 can have an important role in organizing and presenting some types of mitogenic growth factors at the cell surface.

NG2 proteoglycan-binding peptides target tumor neovasculature.

NG2 is the rat homologue of the human melanoma proteoglycan, also known as the high molecular weight melanoma-associated antigen. This developmentally regulated membrane-spanning chondroitin sulfate proteoglycan is expressed primarily by glial, muscle, and cartilage progenitor cells. Upon maturation, these cell types down-regulate NG2 expression. In adult animals, the expression of NG2 is restricted to tumor cells and angiogenic tumor vasculature, making this proteoglycan a potential target for directing therapeutic agents to relevant sites of action. To this end, we have identified specific NG2-binding peptides by screening a phage-displayed random peptide library on purified NG2. Several rounds of biopanning on NG2 resulted in the specific enrichment of two phage-displayed decapeptides, TAASGVRSMH and LTLRWVGLMS. The binding of these phages to NG2 was inhibitable both by soluble NG2 and by glutathione S-transferase (GST) fusion proteins containing the cognate peptide sequences. In addition, direct binding between GST-TAASGVRSMH and GST-LTLRWVGLMS fusion proteins and NG2 was demonstrated in solid-phase binding assays. Interestingly, these NG2-binding fusion proteins cross-inhibited each other's binding to NG2, suggesting that the two sequences bind to the same or overlapping sites on the proteoglycan. Upon injection into tumor-bearing mice, NG2-binding phages specifically homed to tumor vasculature in wild-type mice but did not localize to the tumor vasculature in NG2 knockout mice. The in vivo targeting capability of these sequences suggests that they can be used for tumor targeting.

Lifetime use of alternative therapy: a study of Florida residents.

BACKGROUND: Clinically relevant questions remain about who uses alternative medicine, which treatments they use and why. METHODS: The random digit dialing survey method was used to ask Florida residents about their lifetime use of 11 different alternative therapies. The response rate was 54% (n=1,012). RESULTS: Sixty-two percent of respondents had used one or more of these alternative therapies. Women, unmarried persons, those with regular physicians, and those with poor self-rated health were the highest users. Home remedies were used by 31% of the respondents, followed by special diets (24%), relaxation techniques (20%), and herbal medicines (18%). Acupuncture, biofeedback, energy healing, and hypnosis were used by less than 5% of the sample. CONCLUSIONS: Most respondents used an alternative therapy at some time. Ethnic diversity may be a useful marker for more diversity in alternative therapy. These results affirm the need for accelerated physician education in alternative medicine to help physicians respond appropriately to patients' inquiries about alternative therapy.

Expression of the NG2 proteoglycan enhances the growth and metastatic properties of melanoma cells.

The human homologue of NG2, the human melanoma proteoglycan (HMP), is expressed on most human melanomas. To investigate the role of this proteoglycan in melanoma progression, we have attempted to identify functionally important molecular ligands for NG2. Immunohistochemical analysis of cell lines that endogenously express NG2/HMP suggests that NG2/HMP associates with CD44 and alpha4beta1 integrin, two molecules previously implicated in melanoma progression. Transfection of rat NG2 into the NG2-negative B16 mouse melanoma cell line also resulted in a highly colocalized pattern of expression between the transfected rat NG2 and the endogenously expressed mouse CD44 and alpha4beta1 integrin molecules. In functional assays, expression of NG2 decreased the adhesion of B16 melanoma cells to CD44 monoclonal antibodies, hyaluronic acid, the C-terminal 40-kDa fibronectin fragment, and the CS1 fibronectin peptide, suggesting that NG2 may negatively modulate CD44- and alpha4beta1-mediated binding events. Expression of NG2 increased the proliferation of melanoma cells in culture and increased tumorigenicity in vivo. Moreover, NG2 expression led to increased lung metastasis of B16F1 and B16F10 melanoma cells in experimental metastasis studies. Together, these studies demonstrate that NG2 is capable of modulating the adhesion, proliferation, and metastatic potential of melanoma cells.

The Spiritual Involvement and Beliefs Scale. Development and testing of a new instrument.

BACKGROUND: Spirituality is receiving greater attention in the medical literature, especially in the family practice journals. A widely applicable instrument to assess spirituality has been lacking, however, and this has hampered research on the relationship between spirituality and health in the clinical setting. METHODS: A new instrument, called the Spiritual Involvement and Beliefs Scale, was designed to be widely applicable across religious traditions, to assess actions as well as beliefs to address key components not assessed in other available measures, and to be easily administered and scored. The instrument is a questionnaire containing 26 items in a modified Likert-type format. Following careful pretesting, the instrument was administered to 50 family practice patients and 33 family practice educators. The validity and reliability of the instrument were then evaluated. RESULTS: By several measures, instrument reliability and validity are very good, with high internal consistency (Cronbach's alpha = .92); strong test-retest reliability (r = .92); a clear four-factor structure; and a high correlation (r = .80) with another established measure of spirituality, the Spiritual Well-Being Scale. CONCLUSIONS: The Spiritual Involvement and Beliefs Scale (SIBS) appears to have good reliability and validity. Compared with other instruments that assess spirituality, the SIBS has several theoretical advantages, including broader scope, use of terms that avoid cultural-religious bias, and assessment of both beliefs and actions. More testing is underway to further assess its usefulness.

Patient ethnicity and diagnosis of emotional disorders in women.

BACKGROUND AND OBJECTIVES: Ethnic background and family resources have not been sufficiently examined in relation to emotional disorders and their treatment in primary care settings. This study examined the diagnosis and management of psychological disorders in family practice patients to explore how ethnicity may affect the diagnosis and treatment of emotional disorders. METHODS: A random sample of family practice patients was selected from 1 year of office visits. The charts of 100 African-American and 100 Caucasian women were audited for primary and secondary diagnoses, presenting symptoms, prescriptions, psychotherapy referrals, history of domestic violence and substance use, and family and demographic characteristics. Chi-square tests of association and multiple regression were used to analyze the data. RESULTS: Ethnic background was significantly associated with a diagnosis of a psychiatric disorder; 44% of Caucasian patients were diagnosed with an emotional disorder, compared with 24% of African-Americans. Proportionately more Caucasian patients with psychiatric diagnoses were treated with psychotropic medications. Patient race, marital status, and insurance status explained 15% of the variance in psychiatric diagnoses. CONCLUSIONS: Women's ethnicity is significantly associated with the diagnosis of emotional disorders and their treatment.

A central segment of the NG2 proteoglycan is critical for the ability of glioma cells to bind and migrate toward type VI collagen.

Previous studies have established that the NG2 proteoglycan binds directly to type VI collagen. To further our understanding of the biochemical and functional significance of this interaction we have used NG2 cDNA to construct a series of NG2 mutants with deletions spaced throughout the entire length of the 260-kDa NG2 core protein. Following transfection of these mutant cDNAs into B28 glioma cells, we determined the ability of mutant NG2 molecules to anchor type VI collagen on the cell surface. Eight of 11 transfectant populations were able to anchor type VI collagen. The three NG2 variants incapable of anchoring type VI collagen have deletions clustered within the central one-third of the NG2 ectodomain. These deletions identify a 469-amino-acid domain of NG2 responsible for binding of type VI collagen. Functional consequences of the NG2-type VI collagen interaction were explored by testing the relative ability of NG2-transfected and untransfected glioma cells to migrate toward type VI collagen. NG2-expressing cells exhibited a greater migratory response toward type VI collagen than their NG2-negative counterparts. This enhanced migration could be specifically inhibited with NG2 antibodies. Furthermore, glioma cells expressing NG2 in which the collagen-binding domain was deleted failed to exhibit this enhanced migration, whereas NG2 mutants in which non-collagen-binding regions were deleted continued to exhibit increased chemotaxis toward the type VI collagen. These comparisons confirm the importance of the central collagen-binding domain in mediating functionally important interactions between NG2 and type VI collagen.

Women's health care: cross-cultural encounters within the medical system.

Women, particularly minority women, have inadequate health care and treatment outcomes caused by a number of extrinsic and intrinsic factors. Salient external systems factors addressed in this article include the lack of health insurance and the inadequate organization and delivery of health care services, for example, difficult-to-reach clinic locations and limited hours of operation. The multiple family roles of women often necessitate alterations in adherence and treatment activities to fulfill competing time and resource demands. Furthermore, culturally widespread lay therapeutic activities, and more culturally limited ethnomedical practices, are routinely employed by patients, yet often are unknown or not acknowledged by physicians. Internal factors, that is, beliefs and attitudes and their behavioral outcomes, are described for African-American, Latino-American, Haitian-American, Asian-American and Native American patients. Suggestions are made for the enhancement of interethnic physician-patient communication. The medical encounter is the nexus for many factors that influence the quality of women's health care.

An alternatively spliced, 5'-truncated MAP1B isoform is expressed in the developing chick nervous system.

Our laboratory has previously characterized a keratan sulfate proteoglycan, named claustrin, and shown by molecular cloning that claustrin and the mouse MAP1B protein share high homology, with claustrin representing a 5'-truncated fragment of MAP1B. In the present study, we examine further the relationship between claustrin and MAP1B, and also describe the isolation of a cDNA encoding the 3'-region of MAP1B, which shares 3'-untranslated sequence, but not coding sequence, with claustrin. We call this partial cDNA 3'-MAP1B-related clone (3'-MRC), since it is homologous to the 3'-region of the mouse MAP1B sequence. We show by Northern analysis that distinct mRNAs are recognized by the claustrin and 3'-MRC cDNAs, and by RT-PCR that mRNAs encoding these distinct MAP1B-related molecules are present in embryonic chick brain and cardiac and smooth muscle. Our data also suggest a higher level of expression of claustrin mRNA in astrocyte cultures, when compared to 3'-MRC. Our data therefore provide new evidence that alternatively spliced variants of MAP1B are expressed in brain, and that at least one of these variants encodes the claustrin proteoglycan.

NG2 proteoglycan and the actin-binding protein fascin define separate populations of actin-containing filopodia and lamellipodia during cell spreading and migration.

The transmembrane proteoglycan NG2 is able to interact both with components of the extracellular matrix and with the actin cytoskeleton. An examination of the distribution of NG2 during cell spreading suggests that NG2 can associate with two distinct types of actin-containing cytoskeletal structures, depending on the nature of the stimulus derived from the substratum. On fibronectin-coated dishes, cell surface NG2 associates exclusively with stress fibers developing within the cell. On poly-L-lysine-coated dishes, cell surface NG2 is associated with radial processes extending from the cell periphery. Spreading on fibronectin/poly-L-lysine mixtures, as well as on matrix components such as laminin, tenascin, and type VI collagen, produces cells with mosaic characteristics, i.e., NG2 is associated with both types of structures. NG2-positive radial processes are distinct from a second population of radial structures that contain fascin. NG2-positive extensions appear to be individual self-contained units (filopodia), whereas fascin is associated with actin ribs within sheets of membrane (lamellipodia). NG2- and fascin-positive structures are often localized to opposite poles of spreading cells, suggesting a possible role for the two classes of cellular extensions in the establishment of cell polarity during morphogenesis or migration. Time lapse imaging confirms the presence of lamellipodia on the leading edges of migrating cells, while numerous filopodia are present on trailing edges.

Binding of the NG2 proteoglycan to type VI collagen and other extracellular matrix molecules.

Previous studies have suggested that the NG2 proteoglycan interacts with type VI collagen. We have further characterized this interaction using a solid phase binding assay in which purified NG2 was shown to bind to pepsin-solubilized type VI collagen. In addition, NG2 bound a recombinant alpha2 (VI) collagen chain but did not appreciably bind to the recombinant alpha1 (VI) chain or the N-terminal domain of alpha3 (VI) (N9-N2). Binding of NG2 to type VI collagen was shown to be concentration-dependent and saturable and to depend mainly on the NG2 core protein, since chondroitinase-treated NG2 bound the collagen as well as undigested samples. In addition, the binding studies revealed several other possible ligands for NG2, including type II collagen, type V collagen, tenascin, and laminin. Binding of the proteoglycan to these molecules was also shown to be mediated by domains contained within the NG2 core protein. The ability of NG2 to bind to these extracellular matrix molecules was compared with that of the chondroitin sulfate proteoglycan decorin, revealing an almost identical binding pattern of the two proteoglycans to the different collagen types. In addition, decorin was found to effectively inhibit the ability of NG2 to bind to collagen, thus suggesting that the two proteoglycans may bind to some of the same regions on the collagen substrates. In contrast, decorin did not bind tenascin and was ineffective in inhibiting the binding of NG2 to tenascin or laminin, indicating that NG2 may bind these two molecules using a separate domain that is distinct from its collagen binding region.

Women's use of complementary medicine. Combining mainstream medicine with alternative practices.

Most female patients use some form of complementary medicine some time in their lives. Complementary medicine provides patients with alternative avenues for finding relief from chronic ailments. Patients also enjoy the more personal and holistic approach of complementary practitioners. Increasingly, schools of medicine are incorporating complementary approaches into their training programs, and third-party reimbursement is now available for some forms of complementary therapies. Research into the safety and efficacy of complementary therapies is in its infancy and therefore it is difficult for mainstream physicians to recommend complementary approaches to their patients. Nonetheless, mainstream physicians who incorporate some of the principles of complementary therapies into the own practices may be rewarded by more positive outcomes in their patients.

Advance directives. Population prevalence and demand in Florida.

The level of knowledge is examined about the prevalence of and potential demand for advance directives--living wills and health-care surrogates--by adult residents of the state of Florida. Questions about advance directives were included in random digit dialing telephone surveys of 1,000 Florida residents 18 years of age and older in November 1994 and April 1995. Surveys were completed by 52% of the November sample and 56% of the April sample. Among those responding 88% had heard of living wills and 25% of health-care surrogates; 25% had completed a living will and 8% had designated a health-care surrogate. Of those with no advance directives 73% said they would complete them if the forms were made readily available in convenient locations. Although a relatively high proportion of Florida residents have advance directives, there are independent age and socioeconomic effects in the likelihood of their completion. Advance directives are desired by many more people, but the current methods of educating and availing persons of the appropriate forms are not adequate to meet the demand.

Analysis of proteoglycan expression in developing chicken brain: characterization of a heparan sulfate proteoglycan that interacts with the neural cell adhesion molecule.

In the present study we have characterized the major proteoglycans of chick brain, focusing on their pattern of expression in development and on identifying the heparan sulfate proteoglycan (HSPG) that binds to the neural cell adhesion molecule (NCAM). The major chondroitin sulfate proteoglycans (CSPG) are a heterogeneous group of molecules with an average MW of 450 kDa. Protein core analysis reveals multiple protein cores between 100 and 350 kDa. The HSPGs are somewhat smaller, with an average MW of 350 kDa, and the major brain HSPG possesses a 250 kDa protein core. During development the relative percentage of HSPG decreases from approximately 50% of total sulfate-labeled PG at E6 to 25% by E10. In order to begin to characterize the HSPG that interacts with NCAM, we initially used an antiserum produced against a HSPG which was previously shown to copurify with NCAM (Cole and Burg: Exp Cell Res 182:44-60, 1989). This antiserum immunoprecipitated a HSPG core protein of 250 kDa, corresponding to the major HSPG of chick brain. We also show that the major brain HSPG binds to a synthetic peptide that encodes the heparan sulfate-binding domain of NCAM, and that monoclonal antibodies to a recently identified chick retinal HSPG recognize this NCAM-binding HSPG. This HSPG was immunopurified from E10 chick brain using the 6D2 monoclonal antibody, and has been shown to bind an affinity column containing the heparan sulfate-binding peptide of NCAM. Consistent with its ability to bind NCAM, we show that the intact 6D2 HSPG inhibits cell adhesion to a HBD peptide substratum, and also binds chick brain cells when employed as a substratum.