Identity of nuclear high-mobility-group protein, HMG-1, and sulfoglucuronyl carbohydrate-binding protein, SBP-1, in brain

Doxorubicin induced immune abnormalities and inflammatory responses via HMGB1, HIF1-α and VEGF pathway in progressive of cardiovascular damage

Background

Doxorubicin (DOX) is a commonly used treatment for cancer and the mechanism of DOX-induced cardiomyocyte damage in cardiovascular disease is not fully understood. High-mobility group box 1 (HMGB1), strong induce proinflammatory cytokines via damage associated molecular pattern (DAMP) which its interaction with the receptor of advanced glycation end products (RAGE), that affect cytokine release, and angiogenesis via the role of HMBG1, HIF-1α and VEGF as an important regulator in these cardiac failure processes. Hypoxia-inducible factor-1α (HIF-1α) is plays an important role in the cellular response to systemic oxygen levels of cells and VEGF is an angiogenic factor and can stimulate cellular responses on the surface of endothelial cells will be described

Objective

The aim of this article is to comprehensively review the role of HMGB1, HIF-1α, and VEGF in DOX-induced Cardiovascular Disease and its molecular mechanisms.

Methods

The data in this study were collect by search the keyword combinations of medical subject headings (MeSH) of “HMGB1”, “HIF-1 α”, “VEGF”, “DOX” and “Cardiovascular disease” and relevant reference lists were manually searched in PubMed, EMBASE and Scopus database. All relevant articles in data base above were included and narratively discussed in this review article.

Results

Several articles were revealed that molecular mechanisms of the DOX in cardiomyocyte damage and related to HMGB1, HIF-1α and VEGF and may potential treatment and prevention to cardiovascular disease in DOX intervention.

Conclusion

HMGB1, HIF-1α and VEGF has a pivotal regulator in DOX-induce cardiomyocyte damage and predominantly acts through different pathways. The role of HMGB1 in DOX-induced myocardial damage suggests that HMGB1 is a mediator of DOX-induced damage. In addition, DOX can inhibit HIF-1α activity where DOX can decrease HIF-1α expression and HIF-1α is also responsible for upregulation of several angiogenic factors, including VEGF. VEGF plays an important role in angiogenesis and anti-angiogenesis both in vitro and in vivo and reduces the side effects of DOX markedly. In addition, the administration of anti-angiogenesis will show an inhibitory effect on angiogenesis mediated by the VEGF signaling pathway and triggered by DOX in cells.

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The effect of Doxorubicin (DOX) induced cardiovascular damage via several pathways.

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Cardiovascular damage can involve HMGB1, HIF-1α, and VEGF.

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HMGB1, HIF-1α, and VEGF as a pivotal regulator in DOX-induce cardiomyocyte damage.

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HMGB1, HIF-1α, and VEGF in cardiovascular diseases will be predominantly acting through different pathways.

Proteins Binding to the Carbohydrate HNK-1: Common Origins?

The human natural killer (HNK-1) carbohydrate plays important roles during nervous system development, regeneration after trauma and synaptic plasticity. Four proteins have been identified as receptors for HNK-1: the laminin adhesion molecule, high-mobility group box 1 and 2 (also called amphoterin) and cadherin 2 (also called N-cadherin). Because of HNK-1′s importance, we asked whether additional receptors for HNK-1 exist and whether the four identified proteins share any similarity in their primary structures. A set of 40,000 sequences homologous to the known HNK-1 receptors was selected and used for large-scale sequence alignments and motif searches. Although there are conserved regions and highly conserved sites within each of these protein families, there was no sequence similarity or conserved sequence motifs found to be shared by all families. Since HNK-1 receptors have not been compared regarding binding constants and since it is not known whether the sulfated or non-sulfated part of HKN-1 represents the structurally crucial ligand, the receptors are more heterogeneous in primary structure than anticipated, possibly involving different receptor or ligand regions. We thus conclude that the primary protein structure may not be the sole determinant for a bona fide HNK-1 receptor, rendering receptor structure more complex than originally assumed.

Neural glycomics: the sweet side of nervous system functions

The success of investigations on the structure and function of the genome (genomics) has been paralleled by an equally awesome progress in the analysis of protein structure and function (proteomics). We propose that the investigation of carbohydrate structures that go beyond a cell's metabolism is a rapidly developing frontier in our expanding knowledge on the structure and function of carbohydrates (glycomics). No other functional system appears to be suited as well as the nervous system to study the functions of glycans, which had been originally characterized outside the nervous system. In this review, we describe the multiple studies on the functions of LewisX, the human natural killer cell antigen-1 (HNK-1), as well as oligomannosidic and sialic (neuraminic) acids. We attempt to show the sophistication of these structures in ontogenetic development, synaptic function and plasticity, and recovery from trauma, with a view on neurodegeneration and possibilities to ameliorate deterioration. In view of clinical applications, we emphasize the need for glycomimetic small organic compounds which surpass the usefulness of natural glycans in that they are metabolically more stable, more parsimonious to synthesize or isolate, and more advantageous for therapy, since many of them pass the blood brain barrier and are drug-approved for treatments other than those in the nervous system, thus allowing a more ready access for application in neurological diseases. We describe the isolation of such mimetic compounds using not only Western NIH, but also traditional Chinese medical libraries. With this review, we hope to deepen the interests in this exciting field.

Spatial and temporal diversity of glycome expression in mammalian brain

Mammalian brain glycome remains a relatively poorly understood area compared to other large-scale "omics" studies, such as genomics and transcriptomics due to the inherent complexity and heterogeneity of glycan structure and properties. Here, we first performed spatial and temporal analysis of glycome expression patterns in the mammalian brain using a cutting-edge experimental tool based on liquid chromatography-mass spectrometry, with the ultimate aim to yield valuable implications on molecular events regarding brain functions and development. We observed an apparent diversity in the glycome expression patterns, which is spatially well-preserved among nine different brain regions in mouse. Next, we explored whether the glycome expression pattern changes temporally during postnatal brain development by examining the prefrontal cortex (PFC) at different time point across six postnatal stages in mouse. We found that glycan expression profiles were dynamically regulated during postnatal developments. A similar result was obtained in PFC samples from humans ranging in age from 39 d to 49 y. Novel glycans unique to the brain were also identified. Interestingly, changes primarily attributed to sialylated and fucosylated glycans were extensively observed during PFC development. Finally, based on the vast heterogeneity of glycans, we constructed a core glyco-synthesis map to delineate the glycosylation pathway responsible for the glycan diversity during the PFC development. Our findings reveal high levels of diversity in a glycosylation program underlying brain region specificity and age dependency, and may lead to new studies exploring the role of glycans in spatiotemporally diverse brain functions.

Isomeric Separation and Recognition of Anionic and Zwitterionic N-glycans from Royal Jelly Glycoproteins

Royal jelly has received attention because of its necessity for the development of queen honeybees as well as claims of benefits on human health; this product of the hypopharyngeal glands of worker bees contains a large number of proteins, some of which have been claimed to have various biological effects only in their glycosylated state. However, although there have been glycomic and glycoproteomic analyses in the past, none of the glycan structures previously defined would appear to have potential to trigger specific biological functions. In the current study, whole royal jelly as well as single protein bands were subject to off-line LC-MALDI-TOF MS glycomic analyses, complemented by permethylation, Western blotting and arraying data. Similarly to recent in-depth studies on other insect species, previously overlooked glucuronic acid termini, sulfation of mannose residues and core β-mannosylation of the N-glycans were found; additionally, a relatively rare zwitterionic modification with phosphoethanolamine is present, in contrast to the phosphorylcholine occurring in lepidopteran species. Indicative of tissue-specific remodelling of glycans in the Golgi apparatus of hypopharyngeal gland cells, only a low amount of fucosylated or paucimannosidic glycans were detected as compared with other insect samples or even bee venom. The unusual modifications of hybrid and multiantennary structures defined here may not only have a physiological role in honeybee development, but represent epitopes recognized by pentraxins with roles in animal innate immunity.

Functional roles of glycoconjugates in the maintenance of stemness and differentiation process of neural stem cells

Neural stem cells (NSCs) possess a high proliferative potential and capacity for self-renewal with retention of multipotency to differentiate into brain-forming cells. NSCs have gained a considerable attention because of their potential application in treatment strategies on the basis of transplantation for neurodegenerative disorders and nerve injuries. Although several signaling pathways have been reportedly involved in the fate determination process of NSCs, the molecular mechanisms underlying the maintenance of neural cell stemness and differentiation process remain largely unknown. Glycoconjugates expressed in the NSC niche in the brain offer markers of NSCs; moreover, they serve as cell regulators, which are actively involved in the modulation of signal transduction. The glycans function on NCS surfaces by recruiting growth factor receptors to specific microdomains as components of glycolipids, thereby mediating the ligand-receptor interactions both indirectly and directly as components of proteoglycans and interacting with specific lectin-type receptors as components of ligand glycoproteins. In this review, we outline current knowledge of the possible functional mechanisms of glycoconjugates to determine cell fates, which are associated with their expression pattern and structural characteristic features.

DHA Suppresses Primary Macrophage Inflammatory Responses via Notch 1/ Jagged 1 Signaling

Persistent macrophages were observed in the lungs of murine offspring exposed to maternal LPS and neonatal hyperoxia. Maternal docosahexaenoic acid (DHA) supplementation prevented the accumulation of macrophages and improved lung development. We hypothesized that these macrophages are responsible for pathologies observed in this model and the effects of DHA supplementation. Primary macrophages were isolated from adult mice fed standard chow, control diets, or DHA supplemented diets. Macrophages were exposed to hyperoxia (O₂) for 24 h and LPS for 6 h or 24 h. Our data demonstrate significant attenuation of Notch 1 and Jagged 1 protein levels in response to DHA supplementation in vivo but similar results were not evident in macrophages isolated from mice fed standard chow and supplemented with DHA in vitro. Co-culture of activated macrophages with MLE12 epithelial cells resulted in the release of high mobility group box 1 and leukotriene B₄ from the epithelial cells and this release was attenuated by DHA supplementation. Collectively, our data indicate that long term supplementation with DHA as observed in vivo, resulted in deceased Notch 1/Jagged 1 protein expression however, DHA supplementation in vitro was sufficient to suppress release LTB₄ and to protect epithelial cells in co-culture.

Moonlighting proteins in cancer

Since the 1980s, growing evidence suggested that the cellular localization of proteins determined their activity and biological functions. In a classical view, a protein is characterized by the single cellular compartment where it primarily resides and functions. It is now believed that when proteins appear in different subcellular locations, the cells surpass the expected activity of proteins given the same genomic information to fulfill complex biological behavior. Many proteins are recognized for having the potential to exist in multiple locations in cells. Dysregulation of translocation may cause cancer or contribute to poorer cancer prognosis. Thus, quantitative and comprehensive assessment of dynamic proteins and associated protein movements could be a promising indicator in determining cancer prognosis and efficiency of cancer treatment and therapy. This review will summarize these so-called moonlighting proteins, in terms of a coupled intracellular cancer signaling pathway. Determination of the detailed biological intracellular and extracellular transit and regulatory activity of moonlighting proteins permits a better understanding of cancer and identification of potential means of molecular intervention.

HMGB1 contributes to regeneration after spinal cord injury in adult zebrafish

High mobility group box 1 (HMGB1, also called amphoterin) facilitates neurite outgrowth in early development, yet can exacerbate pathology and inhibit regeneration by inducing adverse neuroinflammation when released from dying cells, suggesting that HMGB1 plays a critical, yet undefined role in neuroregeneration. We explored whether HMGB1 contributes to recovery after complete spinal cord transection in adult zebrafish. Quantitative PCR and in situ hybridization revealed that HMGB1 mRNA levels decreased between 12 h to 11 days after spinal cord injury (SCI), then returned to basal levels by 21 days. Western blot and immunohistological analyses indicated that the time course of HMGB1 protein expression after SCI parallels that of mRNA. Immunofluorescence staining revealed that HMGB1 translocates from nuclei into the cytoplasm of spinal motoneurons at 4 and 12 h (acute stage) following SCI, then accumulates in the nuclei of motoneurons during the ensuing chronic stage (after 6 days following SCI). Immunohistology of transgenic zebrafish, expressing green fluorescent protein in blood vessels, showed enhanced HMGB1 expression in blood vessels in the vicinity of motoneurons. Application of anti-sense HMGB1 morpholinos inhibited locomotor recovery by 34 % and decreased axonal regeneration by 34 % compared to fish treated with a control morpholino. The present study shows that HMGB1 expression increases in both endothelial cells and motoneurons, suggesting that HMGB1 promotes recovery from SCI not only through enhancing neuroregeneration, but also by increasing angiogenesis. The inflammatory effects of HMGB1 are minimized through the decrease in HMGB1 expression during the acute stage.

HMGB1 in development and diseases of the central nervous system

High mobility group box 1 (HMGB1) is widely expressed in cells of vertebrates in two forms: a nuclear "architectural" factor and a secreted inflammatory factor. During early brain development, HMGB1 displays a complex temporal and spatial distribution pattern in the central nervous system. It facilitates neurite outgrowth and cell migration critical for processes, such as forebrain development. During adulthood, HMGB1 serves to induce neuroinflammation after injury, such as lesions in the spinal cord and brain. Receptor for advanced glycation end products and Toll-like receptors signal transduction pathways mediate HMGB1-induced neuroinflammation and necrosis. Increased levels of endogenous HMGB1 have also been detected in neurodegenerative diseases. However, in Huntington's disease, HMGB1 has been reported to protect neurons through activation of apurinic/apyrimidinic endonuclease and 5'-flap endonuclease-1, whereas in other neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis, HMGB1 serves as a risk factor for memory impairment, chronic neurodegeneration, and progression of neuroinflammation. Thus, HMGB1 plays important and double-edged roles during neural development and neurodegeneration. The HMGB1-mediated pathological mechanisms have remained largely elusive. Knowledge of these mechanisms is likely to lead to therapeutic targets for neurological diseases.

HNK-1 epitope-carrying tenascin-C spliced variant regulates the proliferation of mouse embryonic neural stem cells

Neural stem cells (NSCs) possess high proliferative potential and the capacity for self-renewal with retention of multipotency to differentiate into neuronal and glial cells. NSCs are the source for neurogenesis during central nervous system development from fetal and adult stages. Although the human natural killer-1 (HNK-1) carbohydrate epitope is expressed predominantly in the nervous system and involved in intercellular adhesion, cell migration, and synaptic plasticity, the expression patterns and functional roles of HNK-1-containing glycoconjugates in NSCs have not been fully recognized. We found that HNK-1 was expressed in embryonic mouse NSCs and that this expression was lost during the process of differentiation. Based on proteomics analysis, it was revealed that the HNK-1 epitopes were almost exclusively displayed on an extracellular matrix protein, tenascin-C (TNC), in the mouse embryonic NSCs. Furthermore, the HNK-1 epitope was found to be present only on the largest isoform of the TNC molecules. In addition, the expression of HNK-1 was dependent on expression of the largest TNC variant but not by enzymes involved in the biosynthesis of HNK-1. By knocking down HNK-1 sulfotransferase or TNC by small interfering RNA, we further demonstrated that HNK-1 on TNC was involved in the proliferation of NSCs via modulation of the expression level of the epidermal growth factor receptor. Our finding provides insights into the function of HNK-1 carbohydrate epitopes in NSCs to maintain stemness during neural development.

Rpl30 and Hmgb1 are required for neurulation in golden hamster

Neural tube defects (NTDs) are a group of severe congenital malformations resulting from the failure of neurulation. Genes influencing neurulation have been investigated for their contribution to NTDs. Ribosomal protein (Rp) is an abundant and belongs to a high conservative gene family, which has the complex task of coordinating protein biosynthesis in order to maintain cell homeostasis and survival. However, the mechanisms of Rp in the NTDs are unknown. Understanding the mechanisms will lead to new insights into NTDs. In this report, we constructed a cDNA library from neural tube of golden hamster and screened the cDNA library by a subsection screening method (SSS). Our results demonstrate a possible essential role of the RPL30 cDNA gene during neurulation and in the risk of NTDs. Our study also suggests that another gene, HMGB1, may be significantly associated with neurulation and the risk of NTDs.

Analysis of proinflammatory activity of highly purified eukaryotic recombinant HMGB1 (amphoterin)

HMGB1 (amphoterin) is a 30-kDa heparin-binding protein that mediates transendothelial migration of monocytes and has proinflammatory cytokine-like activities. In this study, we have investigated proinflammatory activities of both highly purified eukaryotic HMGB1 and bacterially produced recombinant HMGB1 proteins. Mass analyses revealed that recombinant eukaryotic HMGB1 has an intrachain disulphide bond. In mass analysis of tissue-derived HMGB1, two forms were detected: the carboxyl terminal glutamic acid residue lacking form and a full-length form. Cell culture studies indicated that both eukaryotic and bacterial HMGB1 proteins induce TNF-alpha secretion and nitric oxide release from mononuclear cells. Affinity chromatography analysis revealed that HMGB1 binds tightly to proinflammatory bacterial substances. A soluble proinflammatory substance was separated from the bacterial recombinant HMGB1 by chloroform-methanol treatment. HMGB1 interacted with phosphatidylserine in both solid-phase binding and cell culture assays, suggesting that HMGB1 may regulate phosphatidylserine-dependent immune reactions. In conclusion, HMGB1 polypeptide has a weak proinflammatory activity by itself, and it binds to bacterial substances, including lipids, that may strengthen its effects.

HMGB1 expression and release by bone cells

Immune and bone cells are functionally coupled by pro-inflammatory cytokine intercellular signaling networks common to both tissues and their crosstalk may contribute to the etiologies of some immune-associated bone pathologies. For example, the receptor activator of NF-kappaB ligand (RANKL)/osteoprotegerin (OPG)/receptor activator of NF-kappaB (RANK) signaling axis plays a critical role in dendritic cell (DC) function as well as bone remodeling. The expression of RANKL by immune cells may contribute to bone loss in periodontitis, arthritis, and multiple myeloma. A recent discovery reveals that DCs release the chromatin protein high mobility group box 1 (HMGB1) as a potent immunomodulatory cytokine mediating the interaction between DCs and T-cells, via HMGB1 binding to the membrane receptor for advanced glycation end products (RAGE). To determine whether osteoblasts or osteoclasts express and/or release HMGB1 into the bone microenvironment, we analyzed tissue, cells, and culture media for the presence of this molecule. Our immunohistochemical and immunocytochemical analyses demonstrate HMGB1 expression in primary osteoblasts and osteoclasts and that both cells express RAGE. HMGB1 is recoverable in the media of primary osteoblast cultures and cultures of isolated osteoclast precursors and osteoclasts. Parathyroid hormone (PTH), a regulator of bone remodeling, attenuates HMGB1 release in cultures of primary osteoblasts and MC3T3-E1 osteoblast-like cells but augments this release in the rat osteosarcoma cell line UMR 106-01, both responses primarily via activation of adenylyl cyclase. PTH-induced HMGB1 discharge by UMR cells exhibits similar release kinetics as reported for activated macrophages. These data confirm the presence of the HMGB1/RAGE signaling axis in bone.

Axonal transport of the cellular prion protein is increased during axon regeneration

The cellular prion protein, PrPc, is a glycosylphosphatidylinositol-anchored cell surface glycoprotein and a protease-resistant conformer of the protein may be the infectious agent in transmissible spongiform encephalopathies. PrPc is localized on growing axons in vitro and along fibre bundles that contain elongating axons in developing and adult brain. To determine whether the growth state of axons influenced the expression and axonal transport of PrPc, we examined changes in the protein following post-traumatic regeneration in the hamster sciatic nerve. Our results show (1) that PrPc in nerve is significantly increased during nerve regeneration; (2) that this increase involves an increase in axonally transported PrPc; and (3) that the PrPc preferentially targeted for the newly formed portions of the regenerating axons consists of higher molecular weight glycoforms. These results raise the possibility that PrPc may play a role in the growth of axons in vivo, perhaps as an adhesion molecule interacting with the extracellular environment through specialized glycosylation.

On peptidede novo sequencing: a new approach

A procedure is presented for the automatic determination of the amino acid sequence of peptides by processing data obtained from mass spectrometry analysis. This is a basic and relevant problem in the field of proteomics. Furthermore, it has an even higher conceptual and applicative interest in peptide research, as well as in other connected fields. The analysis does not rely on known protein databases, but on the computation of all amino acid sequences compatible with the given spectral data. By formulating a mathematical model for such combinatorial problems, the structural limitations of known methods are overcome, and efficient solution algorithms can be developed. The results are very encouraging both from the accuracy and computational points of view.

Glycans and neural cell interactions

Carbohydrate-carrying molecules in the nervous system have important roles during development, regeneration and synaptic plasticity. Carbohydrates mediate interactions between recognition molecules, thereby contributing to the formation of a complex molecular meshwork at the cell surface and in the extracellular matrix. The tremendous structural diversity of glycan chains allows for immense combinatorial possibilities that might underlie the fine-tuning of cell-cell and cell-matrix interactions.

Regulated expression and subcellular localization of HMGB1, a chromatin protein with a cytokine function

High mobility group box protein 1 (HMGB1) has been considered as a ubiquitous nuclear protein with an architectural function, but even early reports have described its presence outside of the nucleus. Today, we have only started to understand the extranuclear and extracellular functions of HMGB1: we know that it participates in developmental and differentiation processes, triggers and modulates many of the inflammatory cascades in the body, and may even be involved in the metastatic invasion programme of cancer cells. Given such diverse roles, it is important to know which cells express HMGB1, where, and how much. The present review deals with the expression pattern of HMGB1 and provides evidence that, far from being housekeeping, the HMGB1 gene is tightly regulated. This can have implications for therapeutic intervention on inflammatory diseases as well as cancer.

Amphoterin as an extracellular regulator of cell motility: from discovery to disease

Amphoterin is a ubiquitous and highly conserved protein previously considered solely as a chromatin-associated, nuclear molecule. Amphoterin is released into the extracellular space by various cell types, and plays an important role in the regulation of cell migration, differentiation, tumorigenesis and inflammation. This paper reviews recent research on the mechanistic background underlying the biology of secreted amphoterin, with an emphasis on the role of amphoterin as an autocrine/paracrine regulator of cell migration.

The Effects of Cholesterol-3-sulfate (CH-3S) on the Phosphorylation of Human C3a (hC3a) in Vitro and on the Ability of hC3a to Induce Vascular Permeability in Rats

The phosphorylation of human C3a (hC3a, anaphylatoxin) by two distinct protein kinases (PKA and CK-I) and the effect of cholesterol-3-sulfate (CH-3S) on this phosphorylation were biochemically investigated in vitro. It was found that (i) hC3a functions as a phosphate acceptor for PKA and CK-I, but not for CK-II; (ii) the CK-I-mediated phosphorylation of hC3a requires the presence of 3 microM CH-3S in a manner similar to the phosphorylation of HMG1 (CH-3S-binding protein) by CK-I; and (iii) CH-3S inhibits the PKA-mediated phosphorylation of hC3a in a dose-dependent manner (ID50=approximately 2 microM). As expected, hC3a containing high levels of Arg- and Lys-residues stimulated approx. 3-fold CK-II activity (phosphorylation of alpha-casein) in vitro. However, no significant effect of hC3a on CK-II activity was observed when hC3a was preincubated with CH-3S or fully phosphorylated by PKA in vitro. Furthermore, preincubation of hC3a with CH-3S diminished the ability of hC3a to induce vascular permeability in rats. The results provided here suggest that (i) hC3a is a CH-3S-binding protein; and (ii) CH-3S functions as a potent inhibitor for its physiological activities, including phosphorylation by PKA and CK-I, in vitro.

Regulation of expression of sulfoglucuronyl carbohydrate (HNK-1), Amphoterin and RAGE in retinoic acid-differentiated P19 embryonal carcinoma cells

HNK-1 antibody reactive sulfoglucuronyl carbohydrate (SGC) and SSEA-1 antibody reactive Lewis X (Lex) epitope are expressed on several glycolipids, glycoproteins, and proteoglycans of the nervous system and have been implicated in cell-cell recognition, neurite outgrowth, and/or neuronal migration during development. Interaction of SGC with its binding protein Amphoterin and interaction of Amphoterin with a cell-signaling molecule, receptor for advance glycation end product (RAGE) have been suggested to regulate neurite outgrowth and neuronal migration. The regulation of expression of SGC, Lex, Amphoterin, and RAGE was studied in embryonal carcinoma P19 cells after treatment with retinoic acid (RA). The untreated proliferating P19 cells strongly expressed the Lex epitope, which was mostly due to Lex-glycoproteins. P19 cells, when differentiated into neuron-like cells by RA, did not express the Lex epitope, but expressed increasing levels of SGC, with time in culture. Quantitative biochemical analyses showed that in the P19 cells after RA treatment, the amount of SGC-glycoproteins increased at a significantly higher level than sulfoglucuronyl glycolipid-1 (SGGL-1). The increase in the levels of SGGL-1 was due to 16-fold upregulation in the activity of lactosylceramide: N-acetylglucosaminyl-transferase (Lc3 synthase), which synthesizes the key intermediate lactotriosylceramide (Lc3Cer), for lacto- and neolacto-glycolipids. The large increase in the activity of Lc3 synthase appeared to regulate the levels of other neolacto glycolipids, such as Lc3Cer, nLc4Cer, nLc6Cer, disialosyl-nLc4Cer (LD1), and Lex-glycolipids. Strong upregulation of glucuronyl-transferase and modest twofold enhancement in the activity of the glucuronyl-sulfotransferase, which catalyze the final steps in the SGC synthesis, also would account for the large increase in the synthesis SGC-glycoproteins. RA also upregulated the synthesis of Amphoterin and RAGE in P19 cells. SGC, RAGE, and Amphoterin were co-localized in the RA-differentiated neurons. The initiation of neurite outgrowth along with co-ordinated upregulation of Amphoterin, RAGE, SGC-glycoproteins, and SGGLs in RA-treated P19 cells support the hypothesis that these molecules are involved in the neuronal process formation.

Binding of low molecular mass compounds to proteins studied by liquid chromatographic techniques

The newest achievements in the application of miscellaneous liquid chromatographic techniques such as size-exclusion, ion-exchange and reversed-phase high-performance liquid chromatography, and thin-layer chromatography for the elucidation of the various aspects of the binding of ligands to proteins are compiled and briefly discussed. Examples of employment in pharmaceutical and clinical chemistry, drug design, enzyme kinetic studies and environmental protection are presented.

HNK-1 sulfotransferase null mice express glucuronyl glycoconjugates and show normal cerebellar granule neuron migration in vivo and in vitro

Sulfoglucuronyl carbohydrate (SGC), reactive with antibody against human natural killer cell antigen, is expressed in several glycolipids, glycoproteins and proteoglycans of the nervous system and has been implicated in cell-cell recognition, neurite outgrowth and neuronal migration during development, through its interaction with SGC-binding protein (SBP) 1. However, sulfotransferase (ST) null mutant mice, which lack SGC, were shown to have normal development with usual gross anatomy of the nervous system and other organs. Failure to observe a severe phenotype in the ST null mice prompted us to determine the compensatory molecular replacement of SGC by analyzing the carbohydrate of glycolipids and glycoproteins of the ST mutant nervous system. In the ST null mice, SGC-containing molecules were absent; instead the precursor glucuronyl carbohydrate (GC)-containing molecules accumulated. Other relevant glycolipids and proteins were not affected. The GC molecules in the mutant were localized at the same anatomical sites in the nervous system as the SGC molecules in the wild type. In vitro binding studies showed that, similar to sulfoglucuronyl glycolipids, glucuronyl glycolipids interacted with SBP-1, but with a lower binding capacity. In vitro studies with explant cultures of cerebellum indicated that neurite outgrowth and cell migration were not significantly affected in the mutant, possibly owing to interaction of SBP-1 with GC molecules. The results suggested that in vivo SBP-1-GC interaction was sufficient to allow normal neurite outgrowth and cell migration in the mutant, giving rise to a wild-type phenotype. However, the role of other compensatory molecules involved in these processes cannot be completely ruled out.

Altered expression of novel genes in the cerebral cortex following experimental brain injury

Damage to the cerebral cortex results in neurological impairments such as motor, attention, memory and executive dysfunctions. To examine the molecular mechanisms contributing to these deficits, mRNA expression was profiled using high-density cDNA microarray hybridization after experimental cortical impact injury in mice. The mRNA levels at 2 h, 6 h, 24 h, 3 days and 14 days after injury were compared with those of control animals. This revealed 86 annotated genes and 24 expression sequence tags (ESTs) as being differentially expressed with a 1.5-fold or greater change. Quantitative real-time PCR analysis was used to independently verify these results for selected genes. Seven functional classes of genes were found to be altered following injury, including transcription factors, signal transduction genes and inflammatory proteins. While a few of these genes have been previously reported to be differentially regulated following injury, the most of the genes have not been previously implicated in traumatic brain injury (TBI) pathophysiology. For example, consistent with previous reports, the transcription factor c-jun and the neurotrophic factor bdnf mRNA levels were altered as a result of TBI. Among the novel genes, the mRNA levels for the high mobility group protein 1 (hmg-1), the regulator of G-protein signaling 2 (rgs-2), the transforming growth factor beta inducible early growth response (tieg), the inhibitor of DNA binding 3 (id3), and the heterogeneous nuclear ribonucleoprotein H (hnrnp h) were changed following injury. The functional significance of these genes in neurite outgrowth, neuronal regeneration, and plasticity following injury are discussed.

Immunomodulation by parasites: high mobility group 2 (HMG-2) protein is a putative intracellular mediator for fucosylated sugars of Schistosoma mansoni

Fucosylated sugars in Schistosoma mansoni possess immunomodulatory properties. In order to gain insights to the mechanisms involved, attempts were made to identify host immune cell molecules that specifically recognize these sugars. On Western blots, specific binding of synthetic biotinylated fucose sugars to proteins of approximately 25-27kDa was observed. Three proteins were isolated by affinity chromatography and subjected to protein sequencing. The determined N-terminal sequences and that of tryptic peptides of two proteins did not show homology to known sequences in the NCBI database. The third was identified as a member of the high mobility group 2 (HMG-2) proteins. In vitro stimulation of mouse spleen cells with Lewis(x) sugars up-regulated the expression of HMG-2 mRNA. These data suggest that HMG-2 protein may function as a putative intracellular receptor/mediator for fucosylated sugars of parasites.