Reciprocal Interactions between Lactoferrin and Bacterial Endotoxins and Their Role in the Regulation of the Immune Response

Lactoferrin (Lf), an iron-binding glycoprotein expressed in most biological fluids, represents a major component of the mammalian innate immune system. Lf's multiple activities rely not only on its capacity to bind iron, but also to interact with molecular and cellular components of both host and pathogens. Lf can bind and sequester lipopolysaccharide (LPS), thus preventing pro-inflammatory pathway activation, sepsis and tissue damage. However, Lf-bound LPS may retain the capacity to induce cell activation via Toll-like receptor 4-dependent and -independent mechanisms. This review discusses the complex interplay between Lf and LPS and its relevance in the regulation of the immune response.     

Comparison of anticancer activity between lactoferrin nanoliposome and lactoferrin in Caco-2 cells in vitro

The anticancer activities of Lactoferrin (Lf) and Lf nanoliposomes in Caco-2 cells were observed in this study, and mitochondrial function (MTT assay), count kit-8(CCK-8), detection of intracellular reactive oxygen species (ROS) and apoptosis induction (AO/EB staining) assays were used to evaluate the anticancer activity. MTT results demonstrated that Lf nanoliposomes and Lf reduced the mitochondrial activity of cells in a manner of dose and time effect, and the viabilities of Caco-2 cell were significantly decreased in vitro following exposure to Lf nanoliposomes at the concentrations of 5 and 10 mg/mL. LDH leakage and ROS significantly increased in cells exposed to Lf nanoliposomes (⩾5 mg/mL), while Lf induced ROS only at higher doses (10 mg/mL). CCK-8 evaluation of cell proliferation and AO/EB double staining supported the anti-proliferative effects of Lf liposomes. Our findings demonstrated that the presence of Lf nanoliposome is more significant than Lf in inhibiting human tumor cells proliferation. Therefore, it can be concluded that Lf nanoliposomes are a potential therapeutic modality in the management of tumors.     

Design and Fungicidal Activity of Mucoadhesive Lactoferrin Tablets for the Treatment of Oropharyngeal Candidosis

Lactoferrin (Lf) is a potential drug candidate for the treatment of oropharyngeal Candida infections. However, for an effective therapeutic treatment an appropriate dosage form is required. Therefore a mucoadhesive tablet for buccal application was developed. Tablets of sufficient strength could be produced on high speed tabletting machines, but they could only be obtained when the protein contained at least 7% moisture. The tablet contained sodium alginate both for its release-controlling properties as well as for its mucoadhesive properties. Furthermore, phosphate buffer was added to keep the pH of the saliva in the mouth within the range of 6.5 to 7.5. In this pH range, Lf has shown to have its highest activity against Candida growth inhibition. The tablet formulation containing Lf had the same antifungal properties as compared with Lf alone, because in most cases identical inhibitory concentrations were observed against several clinical isolates of Candida albicans and Candida glabrata. In human volunteers the tablets, containing 250 mg Lf and placed in each pouch, were able to keep the Lf concentration in the saliva at effective levels for at least 2 hr, while the pH of the saliva remained within the desired range. We concluded that the developed mucoadhesive tablet can improve the therapeutic efficacy of Lf and that it is suitable for further clinical research.     

Design and fungicidal activity of mucoadhesive lactoferrin tablets for the treatment of oropharyngeal candidosis

Lactoferrin (Lf) is a potential drug candidate for the treatment of oropharyngeal Candida infections. However, for an effective therapeutic treatment an appropriate dosage form is required. Therefore a mucoadhesive tablet for buccal application was developed. Tablets of sufficient strength could be produced on high speed tabletting machines, but they could only be obtained when the protein contained at least 7% moisture. The tablet contained sodium alginate both for its release-controlling properties as well as for its mucoadhesive properties. Furthermore, phosphate buffer was added to keep the pH of the saliva in the mouth within the range of 6.5 to 7.5. In this pH range, Lf has shown to have its highest activity against Candida growth inhibition. The tablet formulation containing Lf had the same antifungal properties as compared with Lf alone, because in most cases identical inhibitory concentrations were observed against several clinical isolates of Candida albicans and Candida glabrata . In human volunteers the tablets, containing 250 mg Lf and placed in each pouch, were able to keep the Lf concentration in the saliva at effective levels for at least 2 hr, while the pH of the saliva remained within the desired range. We concluded that the developed mucoadhesive tablet can improve the therapeutic efficacy of Lf and that it is suitable for further clinical research.     

Lactoferrin-lipopolysaccharide (LPS) binding as key to antibacterial and antiendotoxic effects

Lactoferrin (Lf), a multifunctional protein of the innate immune response, seems to act as a permeabilizing agent of Gram negative bacteria, apparently due to its interaction with enterobacterial lipopolysaccharide (LPS) on the bacterial surface. In both human and bovine Lf, a six residue sequence lying in an 18-loop region of the lactoferricin domain is key to Lf-LPS binding. There is much evidence that, by its action on LPS, Lf destabilizes the bacterial membrane and therefore increases bacterial permeability. By itself, Lf is not an effective antibacterial agent, but it permits the penetration of the bacterial membrane by some antibacterial substances whose hydrophobicity otherwise limits their efficacy. Additionally, Lf neutralizes free LPS by keeping the latter from forming complexes that activate TLR-4 signaling pathways. Such pathways, when over-activated, lead to the abundant production of pro-inflammatory mediators such as tumor necrosis factor (TNF) with fatal consequences to the host. The effect of Lf in reducing inflammation and destabilizing Gram negative bacteria has clinical implications in the control of sepsis, multiple organ dysfunction and bacterial invasion.     

Protective effects of lactoferrin against intestinal mucosal damage induced by lipopolysaccharide in human intestinal Caco-2 cells

Indirect evidence suggests that lactoferrin (Lf), a major iron-binding protein in human milk, induces enterocyte growth and proliferation, depending on its concentration and affects the function and permeability of the intestinal mucosa. The bacterial endotoxin (lipopolysaccharide, LPS) is known to cause mucosal hyperpermeability in vivo. However, protective effects of Lf against LPS-mediated intestinal mucosal damage and barrier function in epithelial cells are not yet fully clarified. The aim of this study was to investigate whether Lf can reduce the cellular injury and alter epithelial hyperpermeability caused by LPS in human intestinal Caco-2 cells. When cell viability was measured by a WST-1 assay (tetrazolium salt-based assay), the protective effects against LPS-induced damage to Caco-2 cells were observed at doses of 800 and 1000 microg/ml Lf. The barrier function of Caco-2 monolayer tight junctions was assessed by measuring transepithelial electrical resistance (TEER) and permeability of FITC-labeled dextran 4000 (FD-4). The treatment of Caco-2 cells with Lf at doses of 400 and 1000 microg/ml significantly increased TEER as compared to treatment with LPS alone for 2 h (p<0.05). Further, at doses of 400 and 1000 microg/ml, Lf inhibited the enhancement of LPS-mediated permeability in Caco-2 cell monolayer. The results of this study suggest that Lf may have protective effects against LPS-mediated intestinal mucosal damage and impairment of barrier function in intestinal epithelial cells.     

Inhibition of HSV cell-to-cell spread by lactoferrin and lactoferricin

The milk protein lactoferrin (Lf) has multiple functions, including immune stimulation and antiviral activity towards herpes simplex virus 1 and 2 (HSV-1 and HSV-2); antiviral activity has also been reported for the N-terminal pepsin-derived fragment lactoferricin (Lfcin). The anti-HSV mode of action of Lf and Lfcin is assumed to involve, in part, their interaction with the cell surface glycosaminoglycan heparan sulfate, thereby blocking of viral entry. In this study we investigated the ability of human and bovine Lf and Lfcin to inhibit viral cell-to-cell spread as well as the involvement of cell surface glycosaminoglycans during viral cell-to-cell spread. Lf and Lfcin from both human and bovine origin, inhibited cell-to-cell spread of both HSV-1 and HSV-2. Inhibition of cell-to-cell spread by bovine Lfcin involved cell surface chondroitin sulfate. Based on transmission electron microscopy studies, human Lfcin, like bovine Lfcin, was randomly distributed intracellularly, thus differences in their antiviral activity could not be explained by differences in their distribution. In contrast, the cellular localization of iron-saturated (holo)-Lf appeared to differ from that of apo-Lf, indicating that holo- and apo-Lf may exhibit different antiviral mechanisms.     

新型血管生成抑制剂Borrelidin抗肿瘤作用及其合成的研究进展

Borrelidin是从娄彻氏链霉菌代谢产物中分离得到的十八元大环内酯化合物,具有良好的抗菌、抗疟和抗病毒等活性。近年报道其具有血管生成抑制活性(IC50=0.8nM),是潜在的血管生成抑制剂,使Borrelidin再受瞩目,而血管生成抑制剂是目前抗肿瘤药物研究的热点之一,加之Borrelidin结构新颖独特,在药物科研开发领域再度引起了科技工作者的兴趣。本文就Borrelidin的抗肿瘤活性、作用机制及其合成的相关研究进行综述。     

应用Stainer培养基与TFF系统制备白喉类毒素

目的  验证WHO推荐的Stainer培养基与切向流过滤(TFF)系统能否制备符合我国现行规程要求的精制白喉类毒素.方法   用PW8菌株、Stainer培养基进行了三批白喉杆菌产毒培养,用TFF微孔过滤和超滤系统分别进行了澄清与浓缩.毒素经甲醛脱毒后,用TFF超滤系统对类毒素进行了超滤精制,得到三批精制白喉类毒素,按我国现行规程主要技术指标进行评价  .结果   产毒效价分别为180Lf/ml、210Lf/ml和155Lf/ml.精制类毒素纯度分别为1900Lf/mgPN、1860Lf/mgPN、1760Lf/mgPN.毒性试验和毒性逆转试验全部合格.结论   应用Stainer培养基与TFF系统可获得符合我国现行规程要求的精制白喉类毒素.     

甾体生物碱澳洲茄胺的研究进展

澳洲茄胺是来源于茄属植物的一种甾体生物碱,具有多重药理活性,特别是较强的抗肿瘤活性。综述近年来有关其药理活性、作用机制及其合成研究的进展,并对该类化合物作为抗肿瘤药物的开发潜力和发展前景进行展望。     

The therapeutic potential of lactoferrin

Lactoferrin (Lf), a natural defence iron-binding protein, is present in exocrine secretions that are commonly exposed to normal flora: milk, tears, nasal exudate, saliva, bronchial mucus, gastrointestinal fluids, cervicovaginal mucus and seminal fluid. Additionally, Lf is produced in polymorphonuclear leukocytes and is deposited by these circulating cells in septic sites. A principal function of Lf is that of scavenging non-protein-bound iron in body fluids and inflamed areas so as to suppress free radical-mediated damage and decrease accessibility of the metal to invading bacterial, fungal and neoplastic cells. Adequate sources of bovine and recombinant human Lf are now available for development of commercial applications. Among the latter are use of Lf in food preservation, fish farming, infant milk formula and oral hygiene. Other readily accessible body compartments for Lf administration include skin, throat and small intestine. Further research is needed for possible medicinal use in colon and systemic tissues. Although Lf is a natural product and should be highly biocompatible, possible hazards have been documented.     

吴茱萸碱类衍生物的生物活性研究进展

吴茱萸碱是一类从传统中药吴茱萸中分离得到的咔啉喹唑啉酮类生物碱,具有抗肿瘤、抗炎、抗肥胖、抗阿尔茨海默病、抗菌、杀虫等作用.近年来,吴茱萸碱因其较低的细胞毒性、广泛的生物活性及优良的理化性质而成为药物研发领域的热点,尤其在抗肿瘤先导化合物的寻找研究中取得了较大的进展.本文将从生物活性、作用机制及抗肿瘤活性相关的衍生物设计合成等方面对吴茱萸碱的研究进展作一综述.     

The therapeutic potential of lactoferrin

Lactoferrin (Lf), a natural defence iron-binding protein, is present in exocrine secretions that are commonly exposed to normal flora: milk, tears, nasal exudate, saliva, bronchial mucus, gastrointestinal fluids, cervicovaginal mucus and seminal fluid. Additionally, Lf is produced in polymorphonuclear leukocytes and is deposited by these circulating cells in septic sites. A principal function of Lf is that of scavenging non-protein-bound iron in body fluids and inflamed areas so as to suppress free radical-mediated damage and decrease accessibility of the metal to invading bacterial, fungal and neoplastic cells. Adequate sources of bovine and recombinant human Lf are now available for development of commercial applications. Among the latter are use of Lf in food preservation, fish farming, infant milk formula and oral hygiene. Other readily accessible body compartments for Lf administration include skin, throat and small intestine. Further research is needed for possible medicinal use in colon and systemic tissues. Although Lf is a natural product and should be highly biocompatible, possible hazards have been documented.     

A novel bovine lactoferrin peptide,FKCRRWQWRM, suppresses Candida cell growth and activates neutrophils

Abstract: To identify potent new antifungal agents, the Candida cell growth inhibitory activities of six lactoferrin (Lf) peptides consisting of 6–25 amino acid residues (peptide 1, FKCRRWQWRMKKLGAPSITCVRRAF = lactoferricin B; peptide 2, FKCRRWQWRM; peptide 2′, FKARRWQWRM; peptide 3, GAPSITCVRRAF; peptide 4, RRWQWR; and peptide 5, RWQWRM) were examined. Of these, peptide 2 strongly suppressed the multiplication of Candida cells, but other peptides showed only weak activities. In two strains of C. albicans, the minimum inhibitory concentration 100 of peptide 2 (17.3 ± 2.2 µm and 17.5 ± 2.4 µm ) was close to that of miconazole (13.0 ± 1.7 µm and 13.1 ± 1.6 µm ) but markedly different from that of amphotericin B (0.52 ± 0.09 µm and 0.56 ± 0.11 µm ). The suppression of Candida cell growth was additively increased by a combination of peptide 2 with amphotericin B and miconazole. Peptides 1, 3, 4 and 5 and Lf suppressed iron uptake by Candida cells, inversely correlated with their Candida cell growth inhibition activities. However, iron uptake was not inhibited by peptide 2. In addition, peptide 2 upregulated Candida cell killing activity of polymorphonuclear leukocytes (PMN) increasing their superoxide generation, protein kinase C activity, p38 MAPK activity and the expression of p47^phox. These results indicated that the main antimicrobial activity of the Lf peptides is dependent on the N‐terminal half of Lf and that the PMN upregulatory activity of peptide 2 and additive function of peptide 2 with antifungal drugs are useful for prophylaxis and control of candidiasis.     

Human lactoferrin: a novel therapeutic with broad spectrum potential.

Lactoferrin (Lf), a natural defence iron-binding protein, has been found to possess antibacterial, antimycotic, antiviral, antineoplastic and anti-inflammatory activity. The protein is present in exocrine secretions that are commonly exposed to normal flora: milk, tears, nasal exudate, saliva, bronchial mucus, gastrointestinal fluids, cervico-vaginal mucus and seminal fluid. Additionally, Lf is a major constituent of the secondary specific granules of circulating polymorphonuclear neutrophils (PMNs). The apoprotein is released on degranulation of the PMNs in septic areas. A principal function of Lf is that of scavenging free iron in fluids and inflamed areas so as to suppress free radical-mediated damage and decrease the availability of the metal to invading microbial and neoplastic cells. Mechanisms of action of Lf in addition to iron deprivation are also described. Administration of exogenous human or bovine Lf to hosts with various infected or inflamed sites has resulted in some prophylactic or therapeutic effects. However, an adverse response to the protein might occur if it were to stimulate antibody production or if it were to provide iron to the invading pathogen. The recombinant form of human Lf has become available and development of the product for use in a wide range of medical conditions can now be anticipated.     

Regulation of PKB/Akt-pathway in the chemopreventive effect of lactoferrin against diethylnitrosamine-induced hepatocarcinogenesis in rats

BackgroundAbnormal activation of protein kinase B (PKB) is associated with many cancers. This makes inhibition of PKB signaling pathway a promising strategy for cancer therapy. Lactoferrin (Lf) has been reported for its inhibition of tumor growth and metastasis, however, the mechanism is not completely understood. Its anti-hepatocarcinogenic activity has not taken the deserved recognition despite the additional advantages of Lf as an antiviral against hepatitis C virus, the main cause of hepatocellular carcinoma (HCC), and as a targeting ligand for delivering chemotherapeutics to hepatoma cells.MethodsThis study evaluated the anti-hepatocarcinogenic effect of Lf, and the role of PKB in this effect using diethylnitrosamine (DENA)-induced HCC rat model, and a primary cell culture prepared from the induced hepatic lesions (DENA?HCC cell culture).ResultsUp-regulation of activated PKB in the hepatocytes of rats with DENA-induced HCC was observed, as measured biochemically in the liver homogenate, and localized immunohistochemically. This was accompanied by increment of hepatocytes proliferation, and expression of vascular endothelial growth factor and endothelial nitric oxide synthase. Involvement of PKB in DENA-induced HCC was confirmed by the observed decrease in cell proliferation in DENA?HCC cell culture that was treated with PKB inhibitor. In Lf-treated rats, a dose-dependent chemopreventive effect was observed, with decreased expression and activation of PKB, amelioration of the other DENA-induced alterations, and stimulation of apoptosis. In vitro, Lf blocked PKB activator-induced cell proliferation.ConclusionThese findings support the chemopreventive activity of Lf against HCC, and suggest regulation of PKB-pathway as a potential mechanism underlying this effect.     

钩藤的主要成分及生物活性研究进展

目的较全面地论述近年来国内外对中药材钩藤的研究进展。方法对相关文献进行归纳和总结,对钩藤的主要成分和生物活性进行综述。结果钩藤中含有多种化学成分并表现出多种生物活性。结论钩藤具有很好的开发价值,应加强对其活性成分的机制研究。     

Lactoferrin-appended solid lipid nanoparticles of paclitaxel for effective management of bronchogenic carcinoma

Abstract

Lung cancer is a dreadful disease which claims to be more life threatening as compared to total sum up of colon, prostate and breast cancers. Thus, there is an urgent need to develop an effective delivery approach for its management. Paclitaxel (PTX) is one of the well-known choice as antineoplasitic agent used for the treatment of different types of human cancers such as non-small-cell lung, head and neck cancers, leukemia, breast, ovarian and melanoma. Lactoferrin (Lf), a “multifunctional protein” is crucial for natural immunity which is secreted by exocrine glands. Lf receptors are expressed on the apical surface on bronchial epithelial cells. These over-expressed LF receptors can be utilized for the transportation of Lf-conjugated drug or nanocarrier devices. The present study was aimed to develop PTX-loaded Lf-coupled solid lipid nanoparticles (SLNs) for the treatment of lung cancer. PTX-loaded SLNs were prepared, characterized and then coupled with Lf using carbodiimide chemistry. The formulations were characterized by transmission electron microscopy, particle size, polydispersity index and zeta potential, whereas Lf conjugation was confirmed by FT-IR and ¹H NMR and efficiency of prepared system was evaluated by in vitro, ex vivo and in vivo evaluations. The ex vivo cytotoxicity studies on human bronchial epithelial cell lines, BEAS-2B, revealed superior anticancer activity of Lf-coupled SLNs than plain SLNs and free PTX. In vivo biodistribution studies showed higher concentrations of PTX accumulated in lungs via Lf-coupled SLNs than plain SLNs and free PTX. These studies suggested that Lf-coupled PTX-loaded SLNs could be used as potential targeting carrier for delivering anticancer drug to the lungs with the minimal side effects.     

Lactoferrin: structure, function and applications

Lactoferrin (LF) is an 80 kDa iron-binding glycoprotein of the transferrin family that is expressed in most biological fluids and is a major component of the mammalian innate immune system. Its protective effects range from direct antimicrobial activities against a large panel of microorganisms, including bacteria, viruses, fungi and parasites, to anti-inflammatory and anticancer activities. These extensive activities are made possible by mechanisms of action utilising not only the capacity of LF to bind iron but also interactions of LF with molecular and cellular components of both host and pathogens. This review summarises the putative antimicrobial mechanisms, clinical applications and heterologous expression models for LF.     

Studies on lactoferrin nanoparticles of gambogic acid for oral delivery

Abstract

Purpose: Lactoferrin (Lf), a mammalian cationic iron-binding glycoprotein belonging to the transferrin (Tf) family, has been widely used in a variety of fields ranging from treating infant diarrhea and supporting newborn growth to food and pharmaceutical applications. In this study, Lf nanoparticles were firstly used as carriers of gambogic acid (GA) to enhance oral absorption and anti-cancer activity, hence reducing the related toxic effect.

Methods: Gambogic acid-lactoferrin nanoparticles (GL-NPs) were prepared by the nanoparticle albumin-bound (NAB) technology. The formed nanoparticles were characterized by DSC, TEM, etc. In situ intestinal perfusion experiment was performed to clarify the absorption mechanism of GL-NPs. Furthermore in vivo and in vitro anti-tumor activities of GL-NPs were also investigated.

Results: GL-NPs was successfully prepared with about 150?nm mean size, +20?mV ζ potential, 92.3?±?7.2% encapsulation efficiency and 9.04?±?0.7% DL; GL-NPs also exhibited a better stability and a desirable slow release in vitro experiment. The results of in situ intestinal perfusion showed a transformation of GA absorption from passive diffusion into active transport or facilitated diffusion by GL-NPs. MTT assay of GL-NPs showed almost an equal anti-proliferative effect with arginine solution of GA (Arg-GA) in HepG2 cell. The inhibitory rate against S180 tumor mice after oral administration of GL-NPs was up to 86.01% which was1.39-folds of intravenous injection of Arg-GA.

Conclusion: The in vitro results showed that the NAB technology was feasible for industrial production of Lf nanoparticles and the in vivo results proved that the effective GL-NPs is a promising approach for the oral delivery of GA. These obtained research works have also paved the preliminary way for the study of Lf as an oral drug delivery carrier.