Nanotechnology could be defined as the technology that has allowed for the control, manipulation, study, and manufacture of structures and devices in the "nanometer" size range. These nano-sized objects, e.g., "nanoparticles", take on novel properties and functions that differ markedly from those seen from items made of identical materials. The small size, customized surface, improved solubility, and multi-functionality of nanoparticles will continue to open many doors and create new biomedical applications. Indeed, the novel properties of nanoparticles offer the ability to interact with complex cellular functions in new ways. This rapidly growing field requires crossdisciplinary research and provides opportunities to design and develop multifunctional devices that can target, diagnose, and treat devastating diseases such as cancer. This article presents an overview of nanotechnology for the biologist and discusses the attributes of our novel XPclad © nanoparticle formulation that has shown efficacy in treating solid tumors, for single dose vaccination, and oral delivery of therapeutic proteins.

Ghrelin, a recently described endogenous ligand for the growth hormone secretagogue receptor (GHS-R), is produced by stomach cells and is a potent circulating orexigen, controlling energy expenditure, adiposity, and growth hormone secretion. However, the functional role of ghrelin in regulation of immune responses remains undefined. Here we report that GHS-R and ghrelin are expressed in human T lymphocytes and monocytes, where ghrelin acts via GHS-R to specifically inhibit the expression of proinflammatory anorectic cytokines such as IL-1β, IL-6, and TNF-α. Ghrelin led to a dose-dependent inhibition of leptin-induced cytokine expression, while leptin upregulated GHS-R expression on human T lymphocytes. These data suggest the existence of a reciprocal regulatory network by which ghrelin and leptin control immune cell activation and inflammation. Moreover, ghrelin also exerts potent anti-inflammatory effects and attenuates endotoxin-induced anorexia in a murine endotoxemia model. We believe this to be the first report demonstrating that ghrelin functions as a key signal, coupling the metabolic axis to the immune system, and supporting the potential use of ghrelin and GHS-R agonists in the management of disease-associated cachexia.

ABSTRACT

We have sequenced a region from the pgm locus of Yersinia pestis KIM6؉ that confers sensitivity to the bacteriocin pesticin to certain strains of Escherichia coli and Y. pestis. The Y. pestis sequence is 98% identical to the pesticin receptor from Yersinia enterocolitica and is homologous to other TonB-dependent outer membrane proteins. Y. pestis strains with an in-frame deletion in the pesticin receptor gene (psn) were pesticin resistant and no longer expressed a group of iron-regulated outer membrane proteins, IrpB to IrpD. In addition, this strain as well as a Y. pestis strain with a mutation constructed in the gene (irp2) encoding the 190-kDa iron-regulated protein HMWP2 could not grow at 37؇C in a defined, iron-deficient medium. However, the irp2 mutant but not the psn mutant could be cross-fed by supernatants from various Yersinia cultures grown under iron-deficient conditions. An analysis of the proteins synthesized by the irp2 mutant suggests that HMWP2 may be indirectly required for maximal expression of the pesticin receptor. HMWP2 likely participates in synthesis of a siderophore which may induce expression of the receptor for pesticin and the siderophore.

Ghrelin, a recently described endogenous ligand for the growth hormone secretagogue receptor (GHS-R), is produced by stomach cells and is a potent circulating orexigen, controlling energy expenditure, adiposity, and growth hormone secretion. However, the functional role of ghrelin in regulation of immune responses remains undefined. Here we report that GHS-R and ghrelin are expressed in human T lymphocytes and monocytes, where ghrelin acts via GHS-R to specifically inhibit the expression of proinflammatory anorectic cytokines such as IL-1β, IL-6, and TNF-α. Ghrelin led to a dose-dependent inhibition of leptin-induced cytokine expression, while leptin upregulated GHS-R expression on human T lymphocytes. These data suggest the existence of a reciprocal regulatory network by which ghrelin and leptin control immune cell activation and inflammation. Moreover, ghrelin also exerts potent anti-inflammatory effects and attenuates endotoxin-induced anorexia in a murine endotoxemia model. We believe this to be the first report demonstrating that ghrelin functions as a key signal, coupling the metabolic axis to the immune system, and supporting the potential use of ghrelin and GHS-R agonists in the management of disease-associated cachexia.

The mechanisms responsible for prostate cancer metastasis are incompletely understood at both the cellular and molecular levels. In this regard, chemokines are a family of small, cytokine-like proteins that induce motility of neoplastic cells, leukocytes and cancer cells. The current study evaluates the molecular mechanisms of CXCL12 and CXCR4 in prostate cancer cell migration and invasion. We report that functional CXCR4 is significantly expressed by prostate cancer cell lines, LNCaP and PC3, when compared with normal prostatic epithelial cells (PrEC). As measured using motility and invasion chamber assays, prostate cancer cells migrated and invaded through extracellular matrix components in response to CXCL12, at rates that corresponded to CXCR4 expression. Anti-CXCR4 antibodies (Abs) significantly impaired the migration and invasive potential of PC3 and LNCaP cells. CXCL12 induction also enhanced collagenase-1 (metalloproteinase-1 (MMP-1)) expression by LNCaP and PC3 cells. Collagenase-3 (MMP-13) was expressed by prostate cancer cells, but it was not expressed by PrEC cells or modulated by CXCL12. CXCL12 increased MMP-2 expression by LNCaP and PC3; however, MMP-9 expression was elevated only in PC3 cells after CXCL12-CXCR4 ligation. PC3 cells also expressed high levels of stromelysin-1 (MMP-3) after CXCL12 stimulation. CXCL12 also significantly Keywords: chemokine; metastasis; metalloproteinase; stromal cell-derived factor-1; SDF-1 Despite the obvious importance of metastasis, this process remains incompletely understood at both the cellular and molecular levels. 1 Many factors have been implicated in the process of metastasis, but the precise mechanisms for the directional migration of malignant cells into different organs is unknown. [2][3][4] In this regard, chemokines are a super family of small, cytokine-like proteins that inducethrough G-protein-coupled receptor and cytoskeletal rearrangement-the adhesion of neoplastic cells or leukocytes to endothelial cells as well as the directional migration of cancer cells. 5,6 The ability of neoplastic cells to penetrate the basement membrane and then invade the interstitial stroma to initiate the metastatic process is largely mediated by proteolysis. Many proteinases are capable of degrading extracellular matrix (ECM) components, but matrix metalloproteinases (MMPs) appear to be particularly important for matrix degradation. 6 These proteolytic enzymes are involved in connective tissue remodeling as well as in embryonic growth, ovulation, wound healing and menstruation. 7,8 Moreover, abnormal production of these proteinases is implicated in a number of pathological conditions. 9 It has been shown that CXCL12-CXCR4 interactions may play a role in the metastasis of prostate cancer to bone. 10 However, these interactions alone do not explain the metastasis pattern of prostate cancer or the potential for neoplastic prostate cells to migrate and invade other tissues. We have tested the hypothesis that prostate carcinomas use CXCR4-

A deficiency in understanding the steps responsible for colitis is the lack of comprehension for the role chemokines play in mucosal inflammation. IFN-γ-inducible protein-10 (IP-10) and CXCR3 are highly expressed at sites of colitis. Our findings show that IP-10 significantly contributes to the development of Th1 and inflammatory responses. Specifically, IP-10 inhibition in IL-10−/− mice attenuates the associated increases in serum and/or local amyloid A, IL-2, IL-6, TNF-α, IFN-γ, IL-1α, and IL-1β with colitis as compared with IL-10−/− mice that develop colitis similar to human Crohn’s disease. Correspondingly, the rate or intensity of inflammation in IL-10−/− mice treated with anti-IP-10 Abs showed improved scoring of inflammation, compared with control IL-10−/− mice. This study provides important and novel information regarding IP-10 as a target for the treatment of colitis.

Recently, our group purified a rare population of primitive Sca1+/Lin−/CD45− cells from murine bone marrow by employing multiparameter cell sorting. Based on flow cytometric and gene expression analysis, these cells have been shown to express several markers of embryonic stem cells and were accordingly termed Very Small Embryonic-Like stem cells (VSELs). In order to better characterize VSELs, we focused on their morphological parameters (e.g. diameter, nuclear to cytoplasmic ratio, cytoplasmic area) as well as expression of Oct-4. To examine the morphological features of VSELs, we employed a multi-dimensional approach, including (i) traditional flow cytometry, (ii) a novel approach, which is ImageStream (IS) cytometry and (iii) confocal microscopy. We demonstrate by all of the sensitive and precise methods employed, that VSELs are a population of very small cells, which are significantly smaller than haematopoetic stem cells (HSC) (3.63 ± 0.09 versus 6.54 ±0.17 μm in diameter). They also exhibit higher nuclear to cytoplasmic ratio and lower cytoplasmic area as compared with HSCs and mature granulocytes. Besides confirming the size characteristics, confocal microscopic analysis also confirmed that VSELs express Oct-4, a marker of pluripotent embryonic stem cells. Morphological examination reveals that VSELs are unusually small eukaryotic cells that posses several characteristics of embryonic cells. Thus, FACS-based sorting strategies should consider that adult tissues harbour small primitive cells that are larger than platelets and smaller than erythrocytes.