Galectin-3 Research Articles

Nuclear factor (NF)-κB controls expression of the immunoregulatory glycan-binding protein galectin-1

The inflammatory response is a self-limiting process which involves the sequential activation of signaling pathways leading to the production of both pro- and anti-inflammatory mediators. Galectin-1 (Gal-1), an endogenous lectin found in peripheral lymphoid organs and inflammatory sites, elicits a broad spectrum of biological functions predominantly by acting as a potent anti-inflammatory factor and as a suppressive agent for T-cell responses. However, the molecular pathways underlying Gal-1 expression and function remain poorly understood. Here we identified a regulatory loop linking Gal-1 expression and function to NF-κB activation. NF-κB-activating stimuli increased Gal-1 expression on T cells, an effect which could be selectively prevented by inhibitors of NF-κB signaling. Accordingly, transient transfection of the p65 subunit of NF-κB was sufficient to induce high Gal-1 expression. Using in silico studies and chromatin immunoprecipitation analysis we have identified a functional NF-κB binding site within the first intron of the LGALS1 gene. In addition, our results show that exogenous Gal-1 can attenuate NF-κB activation, as shown by inhibition of IκB-α degradation induced by pro-inflammatory stimuli, higher cytoplasmic retention of p65, lower NF-κB DNA binding activity and impaired transcriptional activation of target genes. The present study suggest a novel regulatory loop by which NF-κB induces expression of Gal-1, which in turn may lead to negative control of NF-κB signaling.

The down-regulation of galectin-1 expression is a specific biomarker of arsenic toxicity

Galectin-1 (GAL1) is known as a β-galactoside-binding protein that also can bind with arsenic to regulate cell functions. Using RNA interference technique, we investigated the possible mechanism involved in GAL1 modulation of arsenite-inhibited cell survival in 3T3 fibroblast and KB oral cancer cells. GAL1 gene knockdown significantly attenuated sodium arsenite (NaAsO 2) and arsenic trioxide (As 2O 3) inhibition of cell survival. However, GAL1 gene knockdown did not alter the inhibition of cell survival by antimony chloride, cadmium chloride or nickel sulfate. These results suggested the GAL1 selectively affects particular types of heavy metal elements. Flow cytometric analysis indicated GAL1 gene knockdown also suppressed As(III)-stimulated levels of sub-G1 and G2/M growth arrest in both cells. Moreover, atomic absorption spectrophotometric results showed that GAL1 gene knockdown reduced the total arsenic accumulation of both cells after the NaAsO 2 and As 2O 3 treatment. These results suggested that GAL1 gene knockdown mediates the apoptotic effects of arsenic in 3T3 and KB cells via regulation of the cellular arsenic levels. We propose that down-regulation of GAL1 expression may be a useful and specific biomarker in assessing the toxicity of arsenic exposure.

Inmunohistochemical Profile of Solid Cell Nest of Thyroid Gland

It is widely held that solid cell nests (SCN) of the thyroid are ultimobranchial body remnants. SCNs are composed of main cells and C cells. It has been suggested that main cells might be pluripotent cells contributing to the histogenesis of C cells and follicular cells, as well as to the formation of certain thyroid tumors. The present study sought to analyze the immunohistochemical profile of SCN and to investigate the potential stem cell role of SCN main cells. Tissue sections from ten cases of nodular hyperplasia (non-tumor goiter) with SCNs were retrieved from the files of the Hospital Infanta Luisa (Seville, Spain). Parathormone (PTH), calcitonin (CT), thyroglobulin (TG), thyroid transcription factor (TTF-1), galectin 3 (GAL3), cytokeratin 19 (CK 19), p63, bcl-2, OCT4, and SALL4 expression were evaluated by immunohistochemistry. Patient clinical data were collected, and tissue sections were stained with hematoxylin–eosin for histological examination. Most cells stained negative for PTH, CT, TG, and TTF-1. Some cells staining positive for TTF-1 and CT required discussion. However, bcl-2, p63, GAL3, and CK 19 protein expression was detected in main cells. OCT4 protein expression was detected in only two cases, and SALL4 expression in none. Positive staining for bcl-2 and p63, and negative staining for PTH, CT, and TG in SCN main cells are both consistent with the widely accepted minimalist definition of stem cells, thus supporting the hypothesis that they may play a stem cell role in the thyroid gland, although further research will be required into stem cell markers. Furthermore, p63 and GAL-3 staining provides a much more sensitive means of detecting SCNs than staining for carcinoembryonic antigen, calcitonin, or other markers; this may help to distinguish SCNs from their mimics.

CD56 and High Molecular Weight Cytokeratin as Diagnostic Markers of Papillary Thyroid Carcinoma

BACKGROUNDThe incidence of papillary thyroid carcinoma (PTC) has been increasing recently and a precise diagnosis is essential for optimal treatment. Ancillary immunohistochemical stains are important for diagnosing some difficult cases.METHODSThe dignostic value of CD56, high molecular weight cytokeratin (HMCK), galectin-3 (GAL3), and cytokeratin 19 (CK19) were evaluated to distinguish PTC from other benign thyroid lesions (BTL). We studied 23 cases of papillary thyroid overt carcinomas, 57 papillary thyroid microcarcinomas, five follicular adenomas, five cases of Hashimoto's thyroiditis, and 12 nodular hyperplasias.RESULTSThe statistical analysis showed significantly different expressions of CD56, HMCK, GAL3, and CK19 in PTC vs other BTL. The diagnostic specificity of HMCK and CD56 (90.9% and 72.7%, respectively) was higher than that of GAL3 and CK19 (50.0% and 36.4%, respectively). However, the sensitivity of HMCK and CD56 detection (92.5% and 95.0%, respectively) was lower than that of GAL3 and CK19 (98.8% and 100.0%, respectively). The combined use of CD56, HMCK, GAL3, and CK19 showed 87.5% sensitivity, 100.0% specificity, and 100.0% positive predictive value in differentiating PTC from other BTL.CONCLUSIONSAlthough the differential diagnosis of thyroid follicular lesions are based on histological and cytomorphological criteria, CD56 and HMCK might be useful markers for diagnosing PTC.

Galectin 1 Induction Decreases Radiosensitivity of Patient-generated Primary Cell Lines via Akt Activation

Glioblastoma, grade IV malignant glioma based on the WHO classification, is one of the most common brain tumors found in adults and has a median survival time of fifteen months. The dismal prognosis associated with these tumors is largely due to their ability to grow and proliferate despite radiotherapy, which along with resection and Temozolomide is the current standard of care. A better understanding of the molecular mechanisms that define this malignant phenotype may result in new therapeutic approaches and lead to improvements in how patients are treated. Gene expression analysis of five separate data sets consisting of 676 glioma patients was performed in order to identify targets associated with survival. Galectin 1 (GAL1), a beta-galactosidase binding protein, was found to be adversely associated with survival in this patient population and is expressed in a variety of human cancers. In this study we investigated whether GAL1 mediates cell survival and radioresistance in seven different patient-generated primary cell lines. Patient-generated primary cell lines were isolated and characterized using a variety of assays such as MTS, Annexin V, and cell viability. Western Blot analysis was performed probing for a variety of proteins such as Akt and MAPKs, which play a role in cell proliferation, motility, and apoptosis. Radiation sensitivities were established by Clonogenic Survival Assays comparing the surviving fraction of patient-derived cell lines with one another. Six Gy irradiation upregulated GAL1 and activated phosho-Akt in four of the seven primary cell lines used in this study. Furthermore, the four cell lines that exhibited induction of GAL1 and Akt activation displayed markedly increased radioresistance when compared to primary cell lines that displayed no GAL1 induction and Akt activation. The combination of GAL1 upregulation and phosho-Akt activation following irradiation was associated with a significant decrease in the radiosensitivity of the patient-derived primary cell lines used in our study. Interestingly, the cell lines which showed no upregulation of GAL1 or phospho-Akt activation displayed increased sensitivity to radiation elucidating an interesting association between GAL1, phospho-Akt, and radiosensitivity. The underlying mechanism by which GAL1 may medicate radioresistance appears to be through Akt activation, a well-documents player in cell survival and apoptosis. Our findings in this study show that Galectin 1 is promising target in glioma patients and is worthy of future investigative efforts.

Galectin-3

Galectin-3

The increase of plasma galectin-9 in a patient with insulin allergy: a case report

Allergic reaction to insulin is known to be associated with eosinophilia and hyper IgE. Recent report showed that eosinophilia is related with the increased synthesis of galectin-9 (GAL-9) and osteopontin (OPN). Here, we examined plasma levels of GAL-9 and OPN first time in a case of 65-year old patient with insulin allergy. Insulin aspart & insulin aspart 30 mix were given to the patient and an elevation of the eosinophil count (8440/μl, 17.6 fold) and a moderate increase of IgE (501 U/ml, reference range: 10-350 U/ml), eotaxin-3 (168 pg/ml, 2 fold), histamine (0.95 ng/ml, 5.3 fold) were found 33 days later. The plasma levels of GAL-9 and OPN were 22.5 and 1.7 fold higher than the cut-off point, respectively. After one month cessation of insulin therapy, elevations of the eosinophil count (3,480/μl; 7.3 fold), and OPN (1.4 fold) still occurred but the GAL-9 levels became normal. Therefore, we noted the increases of GAL-9 and OPN in plasma for the first time in a patient with insulin allergy and propose that GAL-9 reflects the conditions of allergy more accurately.

Differential expression of galectin-3 in the hypospadiac male rats induced by Di-n-butyl phthalate

Objective To verify the differential expression of galectin-3 in the genital tubercle (GT) of hypospadiac rats induced by maternal exposure to Di-n-butyl phthalate (DBP) and normal control rats in order to further explore the mechanism of hypospadias. Methods Twenty pregnant SD rats were randomly divided into two groups which were given DBP and soybean oil gavage at the dose of 800 mg/(kg·d) and 2 ml/d separately during the 14-18th day of pregnancy. Fetal rats per fossa, birth weight ( BW) , ano-genital distance (AGD), hapospadias incidence, and harvested GT of fetal rats at GD19.The expression of galectin-3 was analyzed by Western blotting and immunohistochemistry. Results The incidence of hypospadias was 40% , the rat offspring per litter in experiment group was significantly less than in control group (P < 0.05), (experiment group of 8.90 ± 1.25, control group of 13.20 ± 1.46) , BW and AGD/ BW of male offspring in control group were (6.72 ±0.42) g, (0.66 ±0.07) mra/g, those in experiment group were (5.12 ±0.24) g, (0.57 ±0.03) mm/g, and the expression of galectin-3 had statistically significant difference (P < 0.05). Galectin-3 was mainly located in the cytoplasm of epithelium, and staining intensity in control group was stronger than in experimental group. Conclusion Maternal exposure to DBP can reduce the galectin-3 expression in GT epithelium, affect cellular proliferation, apoptosis and urethral fold fusion, and finally result in the occurrence of hypospadias. Key words: Galectin-3; Di-n-butyl phthalate; Hypospadias; Genital tubercle

Galectin-3 secreted by human umbilical cord blood-derived mesenchymal stem cells reduces amyloid-β42 neurotoxicity in vitro

In this study, we found that expression and secretion of galectin-3 (GAL-3) were upregulated by amyloid-β42 (Aβ42) exposure in human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) without cell death. Aβ42-exposed rat primary cortical neuronal cells co-treated with recombinant GAL-3 were protected from neuronal death in a dose-dependent manner. hUCB-MSCs were cocultured with Aβ42-exposed rat primary neuronal cells or the neuroblastoma cell line, SH-SY5Y in a Transwell chamber. Coculture of hUCB-MSCs reduced cell death of Aβ42-exposed neurons and SH-SY5Y cells. This neuroprotective effect of hUCB-MSCs was reduced significantly by GAL-3 siRNA. These data suggested that hUCB-MSC-derived GAL-3 is a survival factor against Aβ42 neurotoxicity.

Galectin 1 and tumor

Galectin 1 as a member of galectin family is widely found in a variety of tumor tissues and cells, and always shows high expression status. Through the intracellular signal transduction, galectin 1 participates in many processes of tumor development and progression such as tumor cells adhesion, proliferation, apoptosis and so on. Therefore, to better understand the signal transduction mechanisms of galectin 1 in tumor development and progression would be likely to treat galectin1 as a novel target for tumor therapy. Key words: Neoplasms; Galectins

The expression of galectin-3 and osteopontin in esophageal carcinoma

Objective To investigate the galectin-3 (Gal-3) and osteopontin (OPN) expression in esophageal carcinoma and analyze its clinical significance.Methods Thirty-seven patients who suffered from esophageal carcinoma were selected from 2006 to 2008.There were 28 males and 9 females,aged from 41 to 82 vears old.The levels of Gal-3 mRNA and OPN mRNA in tissues were detected by Fluorescent PCR,and the levels of Gal-3 and OPN in blood plasma were measured by ELISA.Result The expression of Gal-3 mRNA and OPN mRNA were significantly different between the esophageal carcinoma,side of carcinoma and normal esophagus tissues (F=11.934,F=4.269,P<0.05);The expression of galectin-3 and osteopontin were correlated with pathological grading (F=3.216,P<O.05),but not with the patient's age,gender and pathologic type.In metastasis group,the Gal-3 mRNA and OPN mRNA expression levels were significantly higher that that in un-metastasis group (P<O.05).Conclusion Different expression of Gal-3 and OPN may be related to the incidence.development and metastasis of esophageal cancer.Detection of Gal-3 and OPN of preoperative peripheral blood could be one of the important indicators,which could determine micrometastasis of esophageal carcinoma before operation. Key words: Galectin-3; Osteopontin; Esophageal neoplasms; Micrometastasis

Galectin-1 is a powerful marker to distinguish chondroblastic osteosarcoma and conventional chondrosarcoma

The clinical management of osteosarcoma differs significantly from that of chondrosarcoma; therefore, it is extremely important to diagnose these 2 types of bone tumor accurately. In the absence of a specific marker, differential diagnosis by histochemistry is sometimes impossible, especially between chondroblastic osteosarcoma and conventional chondrosarcoma. We analyzed 165 bone sarcomas by immunohistochemical staining of tissue microarrays for expression of the galectin-1 (GAL1) lectin and by Western blot experiments. We found that GAL1 was abundant in normal human osteoblasts from benign proliferations and in osteosarcomas, including chondroblastic osteosarcomas, but not in chondrosarcomas. There was a highly significant statistical difference in the percentage of stained cells (P < 10(-4)) and in the staining intensity (P < 10(-3)) of chondroblastic osteosarcomas compared to conventional chondrosarcomas. This discriminatory potential of GAL1 staining for osteosarcoma-derived tumors was confirmed by Western blotting. We propose a diagnostic test for bone tumors that takes into account the optimal discriminative values for the percentage of cells stained and the intensity of staining. The positive and negative predictive values were 85.7% (trust interval of 63.7%-97%) and 90% (trust interval of 80%-95.9%), respectively, demonstrating the pertinence of the test. Altogether, our data indicate that GAL1 is a powerful diagnostic marker that distinguishes chondroblastic osteosarcomas from conventional chondrosarcomas.

Abstract 301: Galectin-1 modulates PI3 kinase activity

Abstract The purpose of these experiments was to study the role that Galectin-1 (GAL1) has in Phosphoinositide 3-kinase (PI3K) signaling. GAL1 protein levels have been identified to be significantly upregulated in gliomas. GAL1 levels have also been closely associated with patient survival. The PI3K enzyme converts phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol (3,4,5)-trisphosphate (PIP3). PIP3 serves as a membrane anchor leading to the activation of AKT. PI3K/AKT signaling is important in cancer cell biology because induction of this pathway is associated with increased cell survival, cell cycle progression, and growth. A PIP3 Mass ELISA was performed on cell lysates isolated from wild type (WT) and GAL1 knockdown cells with and without Inslulin-like growth factor 1 (IGF1) stimulation. Briefly, cells were stimulated with 5mM IGF1 followed by cell lysis. Lysates were compared by ELISA for PIP3 levels. Following this an in vitro PI3K assay was done. This assay is designed to measure the activity of a purified PI3K enzyme by detecting PIP2 to PIP3 conversion. Enzyme was incubated with Gal1 alone, LY294002 PI3K inhibitor, or with both Gal1 and the inhibitor. Controls included enzyme only, enzyme with inhibitor, no enzyme, and no substrate. In order to investigate whether a physical interaction was occurring between Gal1 and PI3K, Co-IP experiments were performed. These experiments involved isolation of cell lysates from WT LN229 cells and GAL1 knockdown LN229 cells. Following pulldown, Co-IP's were run on an SDS-PAGE gel, transferred to blots, and probed for GAL1 and p85 α or β. Previous experiments demonstrated a possible role for GAL1 in PI3K signaling and AKT activation. In the PIP3 mass ELISA experiment, WT cells demonstrated elevated cellular PIP3 levels in response to IGF1 stimulation, as expected. GAL1 knockdown cells did not show any increase in PIP3 levels in response to stimulation. We next examined if GAL1 was having a direct effect on PI3K activity. In vitro PI3K reactions showed a specific upregulation of PI3K activity in response to addition of GAL1. In response to 1000-fold changes in GAL1 concentration there was an approximate 2-fold increase in PI3K (p85α/p110α) activity. GAL1 also demonstrated an ability to overcome LY294002 inhibition of the enzyme. Enzyme incubated with both inhibitor and 5uM GAL1 showed 4 times the conversion as compared to enzyme with inhibitor alone. Interaction studies indicate that there is not a physical interaction between GAL1 and either p85 α or β. Future studies characterizing the role of GAL1 in PI3K signaling include repeating the PI3K assay with other PI3K class I isoforms to examine differences. Fluorescence Resonance Energy Transfer (FRET) experiments will also be performed to further test for a physical interaction between PI3K and GAL1. In conclusion GAL1 has demonstrated an ability to effect PI3K activity, and thereby PI3K signaling. However, a physical interaction between GAL1 and PI3K was not observed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 301.

Abstract 357: Induction of galectin-1 decreases radiosensitivity of patient-generated primary cell lines through AKT activation

Abstract Glioblastoma, grade IV malignant glioma based on the WHO classification, is one of the most common brain tumors found in adults and has an average survival time of twelve to sixteen months. The dismal prognosis associated with these tumors is largely due to their ability to grow and proliferate despite radiotherapy, which along with resection and Temozolomide is the current standard of care. A better understanding of the molecular mechanisms that define this malignant phenotype may result in new therapeutic targets and lead to improvements in how patients are treated. Galectin 1(GAL1), a beta-galactosidase binding protein, is strongly expressed in a variety of human cancers and has been shown to be upregulated by irradiation. In this study, we investigated the role of GAL1 upregulation following irradiation in a variety of patient-generated primary cell lines and its role in cell survival. Patient-generated primary cell lines were characterized using a variety of assays such as MTS, Annexin V, and cell viability. Western Blot analysis was performed probing for a variety of proteins implicated in proliferation, motility, and apoptosis. Radiation sensitivities were established by performing Clonogenic Survival Assays comparing the surviving fraction of patient-derived cell lines with established stable cell lines. 6 Gy irradiation upregulated Galectin 1 protein levels in the majority of primary cells used in our study. Furthermore, cell lines which Gal1was upregulated also displayed induction of Phospho-AKT and were significantly less sensitive to irradiation. The combination of GAL1 upregulation and Phosho-AKT induction following irradiation was associated with a significant decrease in the radiosensitization of the patient-derived primary cell lines used in our study. Interestingly, the patient-derived cell lines which showed no upregulation of GAL1 or Phospho-AKT induction displayed markedly increased sensitivity to radiation elucidating an interesting association between GAL1, Phospho-AKT, and radiation-sensitivity. The underlying mechanism by which GAL1 may medicate radioresistence seems to be through AKT activation, a well-documented protein involved in cell survival. Additional studies are ongoing to validate Galectin 1 as a target for radiation sensitization. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 357.

Blood cell oxidative stress precedes hemolysis in whole blood–liver slice co-cultures of rat, dog, and human tissues

A novel in vitro model to investigate time-dependent and concentration-dependent responses in blood cells and hemolytic events is studied for rat, dog, and human tissues. Whole blood is co-cultured with a precision-cut liver slice. Methimazole (MMI) was selected as a reference compound, since metabolism of its imidazole thione moiety is linked with hematologic disorders and hepatotoxicity. An oxidative stress response occurred in all three species, marked by a decline in blood GSH levels by 24 h that progressed, and preceded hemolysis, which occurred at high MMI concentrations in the presence of a liver slice with rat (≥ 1000 μM at 48 h) and human tissues (≥ 1000 μM at 48 h, ≥ 750 μM at 72 h) but not dog. Human blood-only cultures exhibited a decline of GSH levels but minimal to no hemolysis. The up-regulation of liver genes for heme degradation ( Hmox1 and Prdx1), iron cellular transport ( Slc40a1), and GSH synthesis and utilization ( mGST1 and Gclc) were early markers of the oxidative stress response. The up-regulation of the Kupffer cell lectin Lgals3 gene expression indicated a response to damaged red blood cells, and Hp (haptoglobin) up-regulation is indicative of increased hemoglobin uptake. Up-regulation of liver IL-6 and IL-8 gene expression suggested an activation of an inflammatory response by liver endothelial cells. In summary, MMI exposure led to an oxidative stress response in blood cells, and an up-regulation of liver genes involved with oxidative stress and heme homeostasis, which was clearly separate and preceded frank hemolysis.

181: Plasma Galectin 3 Is Increased in Terminal Heart Failure Patients and Is Elevated in Patients Not Surviving Mechanical Circulatory Support

We previously screened patients supported by ventricular assist devices (VAD) for plasma biomarkers related to the regulation of the myocardial extracellular matrix (ECM). We found that galectin 3 (GAL3), a profibrotic, beta-galactosidase binding lectin, was increased in terminal heart failure (HF) patients and appeared to be higher in patients, who died during VAD-support. Therefore, we analysed a large cohort of patients supported by left ventricular assist devices (VAD) and correlated GAL3 plasma levels and outcome.

Galectin-1 and Its Involvement in Hepatocellular Carcinoma Aggressiveness

Hepatocellular carcinoma is one of the most common cancers worldwide. Despite several efforts to elucidate hepatocellular carcinoma molecular pathogenesis, it is still not fully understood. To acquire further insights into the molecular mechanisms of hepatocellular carcinoma, we performed a systematic functional genomic approach on human HuH-7 and JHH-6 cells. The subsequent analysis of the differentially expressed genes in human specimens revealed a molecular signature of 11 genes from which we selected the LGALS1 gene, which was overexpressed in hepatocellular carcinoma. The expression analysis in humans of Galectin-1 (Gal-1), the protein encoded by LGALS1, showed a Gal-1 preferential accumulation in the stromal tissue around hepatocellular carcinoma tumors. Moreover, a significant association between increased expression of Gal-1 in hepatocellular carcinoma and the presence of metastasis was observed. Interestingly, Gal-1 overexpression resulted in an increase of cell migration and invasion. In conclusion, this study provides a portfolio of targets useful for future investigations into molecular marker-discovery studies on a large number of patients and functional assays. In addition, our data provide evidence that Gal-1 plays a role in hepatocellular carcinoma cell migration and invasion, and we suggest that further studies should be conducted to fully establish the role of Gal-1 in hepatocellular carcinoma pathogenesis and evaluate Gal-1 as a potential molecular therapeutic target.

Effect of recombinant galectin‐1 on the growth of immortal rat chondrocyte on chitosan‐coated PLGA scaffold

The effect of galectin-1 (GAL1) on the growth of immortal rat chondrocyte (IRC) on chitosan-modified PLGA scaffold is investigated. The experimental results showed that water absorption ratio of chitosan-modified PLGA scaffold was 70% higher than that of PLGA alone after immersion in ddH(2)O for 2 weeks, indicating that chitosan-modification significantly enhances the hydrophilicity of PLGA. The experimental results also showed that GALl efficiently and spontaneously coats the chitosan-PLGA scaffold surface to promote adhesion and growth of immortal rat chondrocyte (IRC). To investigate the effect of endogenous GAL1, the full-length GAL1 cDNAs were cloned and constructed into pcDNA3.1 vectors to generate a plasmid expressed in IRC (IRC-GAL1). The results showed that IRC-GAL1 growth was significantly higher than that of IRC on chitosan-PLGA scaffold. The GAL1-potentiated IRC growth on chitosan-PLGA scaffold was dose-dependently inhibited by TDG (specific inhibitor of GAL1 binding). These results strongly suggest that GAL1 is critical for enhancing IRC cell adhesion and growth on chitosan-PLGA scaffold. Moreover, GAL1-coating or expression tends to promote IRC cell-cell aggregation on chitosan-PLGA scaffold and significantly enhances IRC migration. These results suggest that GAL1 probably could induce tissue differentiation and facilitates cartilage reconstruction. In conclusion, the experimental results suggest that both GAL1 and chitosan are important for enhancing IRC cell adhesion and growth on PLGA scaffold, and GAL1 is a potential biomaterial for tissue engineering.

Galectin-9(Tim-3L)显著减弱小鼠移植排斥

Objective To explore the subcellular localization of Galectin-9 and its effect on allogeneic immune response.Methods The plasmid pEGFP-N1 was inserted with Galectin-9 fragment which was amplified from pBKCMV-Galectin-9 by PCR.The recombinant plagmid wag then transfected into CHO cells using JetPEI in vitro.The cells were cultured in G418 selecting mediam to obtain the stably-transfected cells.The transcription and expression of Galectin-9 gene were verified by immunohistochemical staining and RT-PCR.The solid-phase transgenic CHO cells or freshly-cultured supernatant wag added into the mixed lymphocyte response system to detect the inhibitory effect of Galectin-9.Galectin-9 protein wag administered intraperitoneally for 7d consecutively.Results The expression of Galectin-9 wag localized in the cytosol of CHO.The allogeneic mix lymphocyte proliferation was dose-dependently inhibited by the freshly-cultured supernatant from stably-transfected CHO cells.Furthermore,the supernatant from stably-transfected CHO cells dose-dependently inhibited the level of IL-2.The inhibitory effect could be reversed by Tim-3-Fc blocking.Administration of Galectin-9 significantly prolonged the survival of allogeneic cardiac transplants[(22.7±1.2)d vs(7.2±0.4)d)].Conclusion Galectin-9 may be secreted in physical situation to exert its immunomodulatory function on allogeneic immune response.Furthermore.Galectin-9 may be a novel therapeutic drug in transplant medicine.

Insecticidal action of mammalian galectin‐1 against diamondback moth (Plutella xylostella)

Previous studies showed that mammalian galectin-1 (GAL1) could interact with chitosan or chitin, one component of the peritrophic membrane (PM). This finding suggests that the PM could be a target of GAL1, which prompted the authors to explore the effect of GAL1 on larval growth and its potential mechanism. The development of Plutella xylostella (L.) larvae was significantly disturbed after they were fed recombinant GAL1. The histochemical structure and immunostaining pattern suggested that GAL1 treatment resulted in dose- and time-dependent disruption of the microvilli and abnormalities in these epithelial cells. Ultrastructural studies showed that the PM was not present in the midgut of GAL1-treated insects; instead, numerous bacteria were found in the lumen area. These results indicate that the protective function of the PM was disrupted by GAL1 treatment. Moreover, in vitro data showed that GAL1 interacts with chitosan/chitin in a dose-dependent manner, and also specifically binds to the PM in vitro. In view of the fact that the carbohydrate recognition domain of GAL1 recognises the structural motif N-acetyl lactosamine (Gal beta 1-4 GlcNAc), which is similar to that of chitin (beta-1,4 N-acetyl-D-glucosamine), it is proposed that the insecticidal mechanism of GAL1 involves direct binding with chitin to interfere with the structure of the PM.