Galectin-1, an alternative signal for T cell death, is increased in activated macrophages

Control of Mycobacterium avium subsp. paratuberculosis load within infected bovine monocyte-derived macrophages is associated with host genetics

The genetic loci influencing individual resistance to Mycobacterium avium subsp. paratuberculosis (MAP) infection are still largely unknown. In the current study, we searched for genetic loci associated with resistance to MAP infection by evaluating the performance of monocyte-derived macrophages (MDMs) isolated from the peripheral blood of 75 healthy Holsteins cows and infected ex vivo with MAP. Bacterial load (log colony-forming units, log CFUs) within MDMs was quantified at 2 h and 7 days p. i. using a BACTEC MGIT 960 instrument. In addition, the expression levels of some genes with important roles in the innate immune response including epiregulin (EREG), complement component C3 (C3), galectin-9 (Gal9), and nitric oxide (NO^-) were measured in the supernatant of the infected cells. DNA from peripheral blood samples of the animals included in the study was isolated and genotyped with the EuroG MD bead Chip (44,779 single nucleotide-polymorphisms, SNPs). Linear mixed models were used to calculate the heritability (h² ) estimates for each indicator of MDM performance, MAP load within MDMs and EREG, C3, Gal9, and NO^-expression. After performing a genome-wide association study, the only phenotypes that showed SNPs with a significant association were the bacterial load within MDMs at 2 h (h² = 0. 87) and 7 days (h² = 0.83) p.i. A total of 6 SNPs, 5 candidate genes, and one microRNA on the Bos taurus chromosomes BTA2, BTA17, BTA18, and BTA21 were associated with MAP load at 2 h p.i. Overlap was seen in two SNPs associated with the log CFUs at 2 h and 7 d p.i. The identified SNPs had negative regression coefficients, and were, therefore, associated with a low bacterial load within MDMs. Some of the identified SNPs were located within QTLs previously associated with longevity, reproductive, and udder health traits. Some of the identified candidate genes; Oxysterol Binding Protein Like 6, Cysteine and Serine Rich Nuclear Protein 3, and the Coiled-Coil Domain Containing 92 regulate cellular cholesterol trafficking and efflux, apoptosis, and interferon production, respectively. Taken together, our results define a heritable and distinct immunogenetic profile in MAP-infected macrophages designed to limit bacterial load early after infection.

Immunohistochemical Analysis of Galectins-1, -3, and -7 in Periapical Granulomas, Radicular Cysts, and Residual Radicular Cysts

INTRODUCTION

Galectins play important roles in immunoinflammatory responses, but their participation in the development of periapical lesions remains unclear. This study aimed to evaluate the expressions of galectins-1, -3, and -7 in periapical lesions, correlating them with the intensity of the inflammatory infiltrate and the pattern of the cystic epithelium.

METHODS

Twenty periapical granulomas (PGs), 20 radicular cysts (RCs), and 20 residual radicular cysts (RRCs) were submitted to immunohistochemistry using anti-galectin-1, -3, and -7 antibodies. The percentage of immunopositive cells in epithelial and connective tissues was determined.

RESULTS

In connective tissue, PGs exhibited higher cytoplasmic/membrane expression of galectins-1 and -7 than RCs and RRCs (P < .05). There was higher nuclear expression of galectin-1 in PGs compared with RCs and RRCs (P < .05). The expression of galectins-1 and -7 in connective tissue was higher in lesions with grade III inflammation (P < .05). No significant differences in galectin-3 immunoexpression were observed for any of the parameters evaluated (P > .05). In the epithelial component, a higher nuclear expression of galectin-7 was detected in RRCs (P < .05), and a higher cytoplasmic/membrane expression of this protein was found in cysts with hyperplastic epithelium (P < .05). Positive correlations were observed between the nuclear and cytoplasmic/membrane expression of galectin-1 in connective tissue (P < .05) as well as between the nuclear and cytoplasmic/membrane expression of galectin-7 in epithelial tissue of cysts (P < .05).

CONCLUSIONS

Galectins-1 and -7 may play important roles in the pathogenesis of PGs, RCs, and RRCs. On the other hand, the present results suggest only a minor involvement of galectin-3 in the development of these lesions.

Stress-induced galectin-1 influences immune tolerance in the spleen and thymus by modulating CD45 immunoreactive lymphocytes

Galectin-1 (Gal-1) is differentially expressed in normal and pathological tissues and regulates immune cell homeostasis. Restraint stress increases serum Gal-1 in rats. However, the function of stress-induced Gal-1 in serum is unknown. We determined if stress-induced Gal-1 in serum accumulates in immunocompetent organs as protection from physiological and/or psychological stress. Western blotting showed that the intensity of Gal-1 bands in stressed groups was significantly higher than that in controls. RT-PCR analysis indicated that the Gal-1 mRNA level did not increase after restraint stress. The numbers of Gal-1 immunoreactive cells in the splenic periarterial lymphatic sheath (PLS) and the thymus medulla of the stressed group were increased compared with those in controls. Furthermore, stress-induced Gal-1 immunoreactive cells corresponded to CD45 immunoreactive lymphocytes (CD45⁺) in the PLS of the spleen and the medulla of the thymus. Thus, stress-induced Gal-1 immediately accumulates in the spleen and thymus, and may modulate the immune response through apoptosis by binding to CD45⁺ lymphocytes in immune organs following physiological and/or psychological stress.

Grafted Activated Schwann Cells Support Survival of Injured Rat Spinal Cord White Matter

BACKGROUND AND OBJECTIVE

The influence of cultured Schwann cells on injured spinal cord in rats is examined.

METHODS

Focal injury of spinal cord white matter at the T10 level was produced using our original non-laminectomy method with a high-pressure air stream. Schwann cells from 7-day predegenerated rat sciatic nerves were cultured, transducted with green fluorescent protein and injected into the cisterna magna (experimental group) 3 times: immediately after spinal cord injury and 3 and 7 days later. Neurons in the brainstem and motor cortex were labeled with FluoroGold (FG) delivered caudally from the injury site a week before the end of the experiment. The functional outcome and morphologic features of neuronal survival were analyzed during a 12-week follow-up. The lesions were visualized and analyzed using magnetic resonance imaging. The maximal distance of expansion of implanted cells in the spinal cord was measured and the number of FG-positive neurons in the brain was counted.

RESULTS

Rats treated with Schwann cells presented significant improvement of locomotor performance and spinal cord morphology compared with the control group. The distance covered by Schwann cells was 7 mm from the epicenter of the injury. The number of brainstem and motor cortex FG-positive neurons in the experimental group was significantly higher than in the control group.

CONCLUSIONS

The data show that activated Schwann cells are able to induce the repair of injured spinal cord white matter. The route of application of cells via the cisterna magna seemed to be useful for their delivery in spinal cord injury therapy.

Proteomics in hematologic malignancies

Basic science research in hematology has been determining the functions of gene products using classical approaches that typically involve studying one or a few genes at a time. Proteomics, defined as the study of protein properties on a large scale, provides tools to globally analyze malignant hematologic cells. A major challenge in cancer therapy is the identification of drugs that kill tumor cells while preserving normal cells. Differential display via proteomics enables analysis of direct as well as side-effects of drugs at a molecular level. Proteomics also allows a better understanding of cell signaling pathways involved during apoptosis in hematologic cells. Storing the information in a 2D electrophoresis database enhances the efficiency of proteome research on malignant cells. Finally, the work needed to be carried out on proteomic analysis prior to routine clinical adoption is discussed, and the necessity for multi-institutional collaborations is emphasized.

Nanoparticle based galectin-1 gene silencing, implications in methamphetamine regulation of HIV-1 infection in monocyte derived macrophages

Galectin-1, an adhesion molecule, is expressed in macrophages and implicated in human immunodeficiency virus (HIV-1) viral adsorption. In this study, we investigated the effects of methamphetamine on galectin-1 production in human monocyte derived macrophages (MDM) and the role of galectin-1 in methamphetamine potentiation of HIV-1 infection. Herein we show that levels of galectin-1 gene and protein expression are significantly increased by methamphetamine. Furthermore, concomitant incubation of MDM with galectin-1 and methamphetamine facilitates HIV-1 infection compared to galectin-1 alone or methamphetamine alone. We utilized a nanotechnology approach that uses gold nanorod (GNR)-galectin-1 siRNA complexes (nanoplexes) to inhibit gene expression for galectin-1. Nanoplexes significantly silenced gene expression for galectin-1 and reversed the effects of methamphetamine on galectin-1 gene expression. Moreover, the effects of methamphetamine on HIV-1 infection were attenuated in the presence of the nanoplex in MDM.

Morphine and galectin-1 modulate HIV-1 infection of human monocyte-derived macrophages

Morphine is a widely abused, addictive drug that modulates immune function. Macrophages are a primary reservoir of HIV-1; therefore, they play a role in the development of this disease, as well as impact the overall course of disease progression. Galectin-1 is a member of a family of β-galactoside-binding lectins that are soluble adhesion molecules and that mediate direct cell-pathogen interactions during HIV-1 viral adhesion. Because the drug abuse epidemic and the HIV-1 epidemic are closely interrelated, we propose that increased expression of galectin-1 induced by morphine may modulate HIV-1 infection of human monocyte-derived macrophages (MDMs). In this article, we show that galectin-1 gene and protein expression are potentiated by incubation with morphine. Confirming previous studies, morphine alone or galectin-1 alone enhance HIV-1 infection of MDMs. Concomitant incubation with exogenous galectin-1 and morphine potentiated HIV-1 infection of MDMs. We used a nanotechnology approach that uses gold nanorod-galectin-1 small interfering RNA complexes (nanoplexes) to inhibit gene expression for galectin-1. We found that nanoplexes silenced gene expression for galectin-1, and they reversed the effects of morphine on galectin-1 expression. Furthermore, the effects of morphine on HIV-1 infection were reduced in the presence of the nanoplex.

K12/SECTM1, an interferon-γ regulated molecule, synergizes with CD28 to costimulate human T cell proliferation

CD7 is a cell-surface molecule, expressed on T lymphocytes and NK cells, which functions as a costimulatory receptor for T cell proliferation. SECTM1 has been proposed as a ligand for CD7. However, the expression pattern of this molecule in human immune cells and role in human T cell function remain unclear. In the present study, using human rSECTM1, we demonstrate that SECTM1 strongly costimulates CD4 and CD8 T cell proliferation and induces IFN-γ production, likely via a CD7-dependent mechanism. In addition, SECTM1 synergizes with suboptimal anti-CD28 to strongly augment T cell functions. We found a robust induction of IL-2 production when SECTM1 and anti-CD28 signals were present with TCR ligation. Furthermore, addition of SECTM1 into a MLR significantly enhanced proliferation of alloantigen-activated T cells, whereas blockade of SECTM1 inhibited T cell proliferation in a two-way MLR assay. Simultaneously blocking the effect of SECTM1, along with CTLA-4/Fc, diminishes two-way MLR. Finally, we demonstrated that expression of SECTM1 is not detected in monocytes and imMoDCs at the protein level. However, it is strongly induced by IFN-γ in monocytes and imMoDCs, and this induction is STAT1-dependent. These results indicate that SECTM1 is a broadly expressed, IFN-γ-inducible molecule, which functions as a potent costimulatory ligand for T cell activation and is synergistic with anti-CD28.

The Galectin-1 level in serum as a novel marker for stress

Galectin-1(Gal-1), a carbohydrate-binding protein with an affinity for beta-galactoside, is widely expressed in various normal and pathological tissues and it also plays an important role in regulating immune cell homeostasis and tumorigenesis. This study investigated the effects of restraint stress on serum Gal-1 by Western blot analyses and enzyme-linked immunosorbent assays. The Gal-1 levels of the restraint-stress group were significantly higher than those of the control group. However, this increase by stress was not obvious in adolescent rats. The pattern of these changes was similar to that of corticosterone. Furthermore, this Gal-1 increase in the serum was prevented by pre-treatment with a neurotoxin 6-hydroxydopamine (6-OHDA), which destroys the noradrenergic nerve terminals. However, a bilateral adrenalectomy (ADX) had no effect on the Gal-1 increase. These results suggest that Gal-1 is a candidate stress marker protein and that the stress-induced increase of Gal-1 in serum is regulated by the sympathetic nervous system under stress conditions.

Transplantation of Schwann cells and/or olfactory ensheathing glia into the contused spinal cord: Survival, migration, axon association, and functional recovery

Schwann cells (SCs) and olfactory ensheathing glia (OEG) have shown promise for spinal cord injury repair. We sought their in vivo identification following transplantation into the contused adult rat spinal cord at 1 week post-injury by: (i) DNA in situ hybridization (ISH) with a Y-chromosome specific probe to identify male transplants in female rats and (ii) lentiviral vector-mediated expression of EGFP. Survival, migration, and axon-glia association were quantified from 3 days to 9 weeks post-transplantation. At 3 weeks after transplantation into the lesion, a 60-90% loss of grafted cells was observed. OEG-only grafts survived very poorly within the lesion (<5%); injection outside the lesion led to a 60% survival rate, implying that the injury milieu was hostile to transplanted cells and or prevented their proliferation. At later times post-grafting, p75(+)/EGFP(-) cells in the lesion outnumbered EGFP(+) cells in all paradigms, evidence of significant host SC infiltration. SCs and OEG injected into the injury failed to migrate from the lesion. Injection of OEG outside of the injury resulted in their migration into the SC-injected injury site, not via normal-appearing host tissue but along the pia or via the central canal. In all paradigms, host axons were seen in association with or ensheathed by transplanted glia. Numerous myelinated axons were found within regions of grafted SCs but not OEG. The current study details the temporal survival, migration, axon association of SCs and OEG, and functional recovery after grafting into the contused spinal cord, research previously complicated due to a lack of quality, long-term markers for cell tracking in vivo.

Regulation of neuronal and glial galectin-1 expression by peripheral and central axotomy of rat primary afferent neurons

Galectin-1 (Gal1) is an endogenously-expressed protein important for the embryonic development of the full complement of primary sensory neurons and their synaptic connections in the spinal cord. Gal1 also promotes axonal regeneration following peripheral nerve injury, but the regulation of Gal1 by axotomy in primary afferent neurons has not yet been examined. Here, we show by immunohistochemistry and in situ hybridization that Gal1 expression is differentially regulated by peripheral nerve injury and by dorsal rhizotomy. Following peripheral nerve injury, the proportion of Gal1-positive DRG neurons was increased. An increase in the proportion of large-diameter DRG neurons immunopositive for Gal1 was paralleled by an increase in the depth of immunoreactivity in the dorsal horn, where Gal1-positive terminals are normally restricted to laminae I and II. Dorsal rhizotomy did not affect the proportions of neurons containing Gal1 mRNA or protein, but did deplete the ipsilateral dorsal horn of Gal1 immunoreactivity, indicating that it is transported centrally by dorsal root axons. Dorsal rhizotomy also resulted in an increase in Gal1 mRNA the nerve peripheral to the PNS-CNS interface (likely within Schwann cells and/or macrophages), and to a lesser extent within deafferented spinal cord regions undergoing Wallerian degeneration. This latter increase was notable in the dorsal columns and along the prior trajectories of myelinated afferents into the deeper dorsal horn. These results show that neuronal and glial expressions of Gal1 are tightly correlated with regenerative success. Thus, the differential expression pattern of Gal1 following peripheral axotomy and dorsal rhizotomy suggests that endogenous Gal1 may be a factor important to the regenerative response of injured axons.

Inhibition by Artocarpus tonkinensis of the Development of Collagen-Induced Arthritis in Rats

Extracts of the leaves and roots from the tree Artocarpus tonkinensis A Cheval (family Moraceae) are used in traditional Vietnamese medicine in order to treat backache as well as rheumatic joint diseases. We prepared an ethyl acetate (EtOAc) extract from this plant and tested its anti-inflammatory properties in an experimental arthritis model, collagen-induced arthritis (CIA). CIA was induced in Dark Agouti rats by means of immunization with collagen type II (CII) emulsified in incomplete Freund's adjuvant. Starting at the day of immunization, the rats were treated daily with intraperitoneal injections of Artocarpus extract. Arthritis progression was measured by means of clinical scoring of paws and anti-CII antibody titres were measured by means of ELISA. In vitro, lymph node (LN) cell cultures were treated with Artocarpus extract and the apoptosis-inducing effect was determined with FACS staining by using annexin V and propidium iodide as well as the TUNEL method. Treatment of the rats with Artocarpus extract decreased arthritis incidence and severity and delayed disease onset. When treatment was started after the onset of arthritis, a tendency towards arthritis amelioration was observed. In vitro, Artocarpus extract acted as a T-cell modulator, inhibiting mitogen-induced T-cell proliferation and inducing apoptosis of activated LN-derived lymphocytes. Thus, we have demonstrated that an EtOAc extract of Artocarpus, a plant traditionally used in Vietnamese folk medicine for treating arthritic conditions, has beneficial effects in an experimental arthritis model. This effect is likely to be T cell-dependent and mediated through apoptosis induction in activated cells.

Regulated expression and effect of galectin-1 on Trypanosoma cruzi-infected macrophages: modulation of microbicidal activity and survival

Galectin-1 is a beta-galactoside-binding protein with potent anti-inflammatory and immunoregulatory effects. However, its expression and function have not been assessed in the context of an infectious disease. The present study documents, for the first time, the regulated expression of galectin-1 in the context of an infectious process and its influence in the modulation of macrophage microbicidal activity and survival. A biphasic modulation in parasite replication and cell viability was observed when macrophages isolated from Trypanosoma cruzi-infected mice were exposed to increasing concentrations of galectin-1. While low concentrations of this protein increased parasite replication and did not affect macrophage survival, higher inflammatory doses of galectin-1 were able to commit cells to apoptosis and inhibited parasite replication. Furthermore, galectin-1 at its lowest concentration was able to down-regulate critical mediators for parasite killing, such as interleukin 12 (IL-12) and nitric oxide, while it did not affect IL-10 secretion. Finally, endogenous galectin-1 was found to be up-regulated and secreted by the J774 macrophage cell line cultured in the presence of trypomastigotes. This result was extended in vivo by Western blot analysis, flow cytometry, and reverse transcription-PCR using macrophages isolated from T. cruzi-infected mice. This study documents the first association between galectin-1's immunoregulatory properties and its role in infection and provides new clues to the understanding of the mechanisms implicated in host-parasite interactions during Chagas' disease and other parasite infections.