BioMetals (v.23, #3)

This is a short preface of this Special Issue Lactoferrin, it described the major points of key reporters in ‘The 9th International Conference on LF Structure, Function and Applications’ in Beijing in late Autumn 2009, and the major articles published in this issue. A panaroma and the lastest advances of lactoferrin R&D during past two years (2007–2009) was tried to extract.
Keywords: Lactoferrin; Research and development; Advances

Lactoferrin: the path from protein to gene by Christina T. Teng (359-364).
This review focuses on the basic research that was performed on the lactoferrin protein and gene that was conducted in my laboratory over the past 25 years. This manuscript will outline how we discovered that lactoferrin is a target gene for estrogen, and how the first mouse lactoferrin cDNA, promoter and gene was cloned. Additionally, study was further extended to investigating the human lactoferrin protein and gene. Lastly the expression of lactoferrin in various tissues of both human and rodent under various physiological conditions were examined.
Keywords: Gene; Estrogen regulation; Reproduction; Cancer; Methylation and SNPs; Promoter

A critical review of the roles of host lactoferrin in immunity by Dominique Legrand; Joël Mazurier (365-376).
Lactoferrin (Lf) is an essential element of innate immunity, which refers to antigen-nonspecific defense mechanisms that a host uses immediately or within hours after exposure to an antigen. Following infection, Lf is released from neutrophils (PMNs) in blood and inflamed tissues and, such as other soluble pattern-recognition receptors of the innate immunity, Lf recognizes unique microbial molecules called pathogen-associated molecular patterns (PAMPs): LPS from the gram-negative cell wall and bacterial unmethylated CpG DNA. However, unlike classical PAMPs receptors involved in the activation of immune cells, Lf may act either as a competitor for these receptors or as a partner molecule, depending on the physiological status of the organism. These immunomodulatory properties are explained by the ability of Lf to interact with proteoglycans and receptors on the surface of mammalian cells: cells of the innate (NK cells, neutrophils, macrophages, basophils, neutrophils and mast cells) and adaptive [lymphocytes and antigen-presenting cells (APCs)] immune systems, and also epithelial and endothelial cells. Through these interactions, Lf is able to modulate the migration, maturation and functions of immune cells, and thus to influence both adaptive and innate immunities. The understanding of the roles of the host-expressed Lf in immunity comes from in vivo and in vitro studies with exogenous Lf which, although informative, rarely reflect the pathological, or non-pathological, conditions in the organism. In this review, the data from the literature will be critically analyzed in order to present a real picture of the regulatory roles of host Lf in immunity.
Keywords: Lactoferrin; Immunity; Immunomodulation; Immune cells; Lipopolysaccharides

The lactoferrin receptor complex in gram negative bacteria by Amanda J. Beddek; Anthony B. Schryvers (377-386).
Bacteria that inhabit the respiratory and genitourinary tracts of mammals encounter an iron-deficient environment on the mucosal surface where iron is complexed by the host iron-binding proteins transferrin and lactoferrin. Lactoferrin is also present in high concentrations at sites of inflammation where the cationic anti-microbial peptide lactoferricin is produced by proteolysis of lactoferrin. Several members of the Neisseriaceae and Moraxellaceae families express surface receptors, capable of specifically binding host lactoferrin and extracting the iron from lactoferrin as a source of iron for growth. The receptor is comprised of an integral outer membrane protein, lactoferrin binding protein A (LbpA), and a largely exposed surface lipoprotein, lactoferrin binding protein B (LbpB). LbpA is essential for mediating growth using lactoferrin as a sole iron source whereas LbpB only plays a facilitating role. LbpB, with the presence of a large tract of negatively charged residues, appears to protect the bacterial cell from the bactericidal effects of the lactoferricin. The lactoferrin receptors in these species appear to be essential for survival and thus may serve as potential vaccine targets.
Keywords: Lactoferrin; Iron utilisation; Lactoferrin binding; Lactoferricin; Gram negative bacteria; Neisseria; Moraxella

Immunoregulatory role of lactoferrin-lipopolysaccharide interactions by Patrizia Puddu; Daniela Latorre; Piera Valenti; Sandra Gessani (387-397).
Lactoferrin (Lf) is a mammalian exclusive protein widely distributed in milk and exocrine secretions exhibiting multifunctional properties. Many of the proven or proposed functions of Lf, apart from its iron binding activity, depend on its capacity to bind to other macromolecules. Lf can bind and sequester lipopolysaccharide (LPS), thus preventing pro-inflammatory pathway activation, sepsis and tissue damage. However, the interplay between Lf and LPS is complex, and may result in different outcomes, including both suppression of the inflammatory response and immune activation. These findings are critically relevant in the development of Lf-based therapeutic interventions in humans. Understanding the molecular basis and functional consequences of Lf-LPS interaction will provide insights for determining its role in health and disease.
Keywords: Lactoferrin; Lipopolysaccharide; Inflammation; Immune response

Cancer prevention by bovine lactoferrin: from animal studies to human trial by Hiroyuki Tsuda; Takahiro Kozu; Gen Iinuma; Yasuo Ohashi; Yutaka Saito; Daizo Saito; Takayuki Akasu; David B. Alexander; Mitsuru Futakuchi; Katsumi Fukamachi; Jiegou Xu; Tadao Kakizoe; Masaaki Iigo (399-409).
Colorectal cancer (CRC) is one of the most frequently diagnosed cancers and, despite improved colonoscopic screening, CRC is a leading cause of death from cancer. Administration of bovine lactoferrin (bLF) suppresses carcinogenesis in the colon and other organs of test animals, and recently it was shown that ingestion of bLF inhibits the growth of adenomatous polyps in human patients. Here we review work which established bLF as an anti-carcinogenic agent in laboratory animals and the results of a clinical trial which demonstrated that bLF can reduce the risk of colon carcinogenesis in humans.
Keywords: Bovine lactoferrin; Chemoprevention; Colorectal cancer

Lactoferrin efficacy versus ferrous sulfate in curing iron deficiency and iron deficiency anemia in pregnant women by Rosalba Paesano; Francesca Berlutti; Miriam Pietropaoli; Fabrizio Pantanella; Enrica Pacifici; William Goolsbee; Piera Valenti (411-417).
Iron deficiency (ID) and iron deficiency anemia (IDA) are the most common iron disorders throughout the world. ID and IDA, particularly caused by increased iron requirements during pregnancy, represent a high risk for preterm delivery, fetal growth retardation, low birth weight, and inferior neonatal health. Oral administration of ferrous sulfate to cure ID and IDA in pregnancy often fails to increase hematological parameters, causes adverse effects and increases inflammation. Recently, we have demonstrated safety and efficacy of oral administration of 30% iron saturated bovine lactoferrin (bLf) in pregnant women suffering from ID and IDA. Oral administration of bLf significantly increases the number of red blood cells, hemoglobin, total serum iron and serum ferritin already after 30 days of the treatment. The increasing of hematological values by bLf is related to the decrease of serum IL-6 and the increase of serum hepcidin, detected as prohepcidin, whereas ferrous sulfate increases IL-6 and fails to increase hematological parameters and prohepcidin. bLf is a more effective and safer alternative than ferrous sulfate for treating ID and IDA in pregnant women.
Keywords: Iron deficiency; Iron deficiency anemia; Lactoferrin; Pregnant women; Inflammation

Periodontitis, periodontopathic bacteria and lactoferrin by Hiroyuki Wakabayashi; Ichiro Kondo; Tetsuo Kobayashi; Koji Yamauchi; Tomohiro Toida; Keiji Iwatsuki; Hiromasa Yoshie (419-424).
Lactoferrin (LF) is a component of saliva and is suspected to be a defense factor against oral pathogens including Streptococcus mutans and Candida albicans. Periodontitis is a very common oral disease caused by periodontopathic bacteria. Antimicrobial activities and other biological effects of LF against representative periodontopathic bacteria, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia, have been widely studied. Association of polymorphisms in LF with incidence of aggressive periodontitis and the role of LF in the gingival crevicular fluid as a marker of periodontitis severity have also been reported. Periodontopathic bacteria reside as a biofilm in supragingival and subgingival plaque. Our recent study indicated that LF exhibits antibacterial activity against planktonic forms of P. gingivalis and P. intermedia at higher concentrations, and furthermore, LF effectively inhibits biofilm formation and reduces the established biofilm of these bacteria at physiological concentrations. A small-scale clinical study indicated that oral administration of bovine LF reduces P. gingivalis and P. intermedia in the subgingival plaque of chronic periodontitis patients. LF seems to be a biofilm inhibitor of periodontopathic bacteria in vitro and in vivo.
Keywords: Lactoferrin; Periodontitis; Periodontopathic bacteria; Plaque; Biofilm

Lactoferrin as an effector molecule in the skeleton by Jillian Cornish; Dorit Naot (425-430).
Lactoferrin is a pleiotropic factor with potent antimicrobial and immunomodulatory activities. In recent years, studies have shown that lactoferrin also acts on the skeleton to promote bone growth. Lactoferrin stimulates the proliferation and differentiation of the bone forming cells, the osteoblasts, and acts as a survival factor for these cells. Lactoferrin also inhibits osteoclastogenesis, reducing the number of cells that can actively resorb bone, thus producing a greater overall increase in bone volume. In vivo, local injection of lactoferrin results in substantial increases in bone area, establishing lactoferrin as an effector molecule in the skeleton. Investigations of the mechanism of action of lactoferrin in bone cells showed that the mitogenic effect of lactoferrin in osteoblasts is mediated mainly through LRP1, a member of the low density lipoprotein receptor-related proteins. Lactoferrin induces activation of p42/44 MAPK signaling as well as PI3-kinase-dependent phosphorylation of Akt in osteoblasts. Differential gene expression studies indicated a possible role for the activation of IGF1, Ptgs2 and Nfatc1 in mediating the mitogenic activity of lactoferrin in osteoblasts. Lactoferrin is a positive regulator of bone with a possible physiological role in bone growth and healing. There is a growing interest in the potential use of lactoferrin for the improvement of bone health, and in a number of recent studies dietary lactoferrin supplementation improved bone mineral density and bone strength. Lactoferrin appears to be a promising candidate for the development of an anabolic therapeutic factor for osteoporosis.
Keywords: Lactoferrin; Bone; Osteoblast; Osteoclast; Anabolic

The investigation of the recombinant bovine lactoferrin-derived antimicrobial protein (rBLfA) demonstrates that the inter-lobe region of bovine lactoferrin contributes to iron binding stability and antimicrobial activity against Staphylococcus aureus. rBLfA containing N-lobe (amino acid residues 1–333) and inter-lobe region (residues 334–344) was expressed in Pichia pastoris at shaking flask and fermentor level. The recombinant intact bovine lactoferrin (rBLf) and N-lobe (rBLfN) were expressed in the same system as control. The physical–chemical parameters of rBLfA, rBLfN and rBLf including amino acid residues, molecular weight, isoelectric point, net positive charge and instability index were computed and compared. The simulated tertiary structure and the calculated surface net charge showed that rBLfA maintained original structure and exhibited a higher cationic feature than rBLf and rBLfN. The three proteins showed different iron binding stability and antimicrobial activity. rBLfA released iron in the pH range of 7.0–3.5, whereas rBLfN lost its iron over the pH range of 7.0–4.0 and iron release from rBLf occurred in the pH range of 5.5–3.0. However, the minimum inhibition concentration of rBLfA against S. aureus ATCC25923 was 6.5 μmol/L, compared with 12.5 and 25 μmol/L that of rBLfN and rBLf, respectively. These results revealed that S. aureus was more sensitive to rBLfA than rBLfN and rBLf. It appeared that the strong cationic character of inter-lobe region related positively to the higher anti-S. aureus activity.
Keywords: Bovine lactoferrin; Inter-lobe region; Iron binding; Antimicrobial activity; Recombinant expression

Discrimination and evaluation of lactoferrin and delta-lactoferrin gene expression levels in cancer cells and under inflammatory stimuli using TaqMan real-time PCR by Esthelle Hoedt; Stephan Hardivillé; Christophe Mariller; E. Elass; Jean-Paul Perraudin; Annick Pierce (441-452).
The lactoferrin gene is known to be expressed either constitutively or under inducible conditions such as hormonal stimuli or inflammation. Its transcription from alternative promoters leads to two products, lactoferrin (Lf) and delta-lactoferrin (ΔLf) mRNAs the expressions of which are altered during oncogenesis. The comparison of the two enhancer/promoter regions revealed that the two isoforms might be differentially trans-activated. Nevertheless, concomitant expression of both transcripts has been found in some normal tissues and in a subset of breast cancer cell lines and biopsies. Moreover, we found putative inflammatory response elements in both P1 and P2 promoter regions suggesting that both Lf and ΔLf might be upregulated under inflammatory stimuli. Therefore, a duplex Taqman gene expression assay has been developed and used to profile mRNA expression of the Lf gene in the case of cancer and under inflammatory conditions. Discrimination between the two transcripts is achieved by using a primer pairs/probe set within exon 1β for ΔLf and a primer pairs/probe set within exon 1 and exon 2 for Lf. In this study, we confirmed that Lf/ΔLf Taqman gene expression assay is a powerful tool to investigate the expression of both Lf and ΔLf transcripts. We also showed that lymphocytes and leukocytes isolated from fresh human blood expressed an extremely high level of ΔLf messengers. An extensive series of cancer cell lines has been studied confirming that both P1 and P2 promoter regions of the Lf gene are downregulated or silenced in the case of cancer. Furthermore, using stimulation by bacterial lipopolysaccharides (LPS), we showed that in MDA-MB-231 and HT-29 epithelial cells, Lf expression is strongly increased with a higher expression level in MDA-MB-231 whereas ΔLf expression is not. These results suggest that the NF-κB/cRel response elements present in the P1 promoter region are functional whereas those present in the P2 promoter region are not and show that ΔLf is not regulated in inflammatory conditions.
Keywords: Lactoferrin; Delta-lactoferrin; TaqMan real-time PCR; Q-PCR; Cancer; LPS

Lactoferrin is a multi-functional metal-binding glycoprotein that exhibits many biological functions of interest to many researchers from the fields of clinical medicine, dentistry, pharmacology, veterinary medicine, nutrition and milk science. To date, a number of academic reports concerning the biological activities of lactoferrin have been published and are easily accessible through public data repositories. However, as the literature is expanding daily, this presents challenges in understanding the larger picture of lactoferrin function and mechanisms. In order to overcome the “analysis paralysis” associated with lactoferrin information, we attempted to apply a text mining method to the accumulated lactoferrin literature. To this end, we used the information extraction system GENPAC (provided by Nalapro Technologies Inc., Tokyo). This information extraction system uses natural language processing and text mining technology. This system analyzes the sentences and titles from abstracts stored in the PubMed database, and can automatically extract binary relations that consist of interactions between genes/proteins, chemicals and diseases/functions. We expect that such information visualization analysis will be useful in determining novel relationships among a multitude of lactoferrin functions and mechanisms. We have demonstrated the utilization of this method to find pathways of lactoferrin participation in neovascularization, Helicobacter pylori attack on gastric mucosa, atopic dermatitis and lipid metabolism.
Keywords: Lactoferrin; Text mining; Neovascularization; Angiogenesis; Helicobacter pylori ; Atopic dermatitis; Lipid metabolism

Bovine lactoferrin inhibits Influenza A virus induced programmed cell death in vitro by Agostina Pietrantoni; Eleonora Dofrelli; Antonella Tinari; Maria Grazia Ammendolia; Simona Puzelli; Concetta Fabiani; Isabella Donatelli; Fabiana Superti (465-475).
Influenza is one of the main plagues worldwide. The statistical likelihood of a new pandemic outbreak, together with the alarming emergence of influenza virus strains that are resistant to available antiviral medications, highlights the need for new antiviral drugs. Lactoferrin, a 80 kDa bi-globular iron-binding glycoprotein, is a pleiotropic factor with potent antimicrobial and immunomodulatory activities. Although the antiviral effect of lactoferrin is one of its major biological functions, the mechanism of action is still under debate. In this research, we have analyzed the effect of bovine lactoferrin (bLf) on Influenza A virus infection in vitro. Our results showed that (i) Influenza virus infected cells died as a result of apoptosis, (ii) bLf treatment inhibited programmed cell death by interfering with function of caspase 3, a major virus-induced apoptosis effector, and (iii) bLf efficiently blocked nuclear export of viral ribonucleoproteins so preventing viral assembly. These results provide further insights on the antiviral activity of bLf and suggest novel strategies for treatment of Influenza virus infection.
Keywords: Bovine lactoferrin; Influenza virus; MDCK cells; Apoptosis

The skeleton is formed by two different mechanisms. In intramembranous ossification, osteoblasts form bone directly, whereas in endochondral ossification, chondrocytes develop a cartilage template, prior to osteoblast-mediated skeletogenesis. Lactoferrin is an iron-binding glycoprotein belonging to the transferrin family. It is known to promote the growth and differentiation of osteoblasts. In this study, we investigated the effects of bovine lactoferrin on the chondrogenic differentiation of ATDC5 chondroprogenitor cells. This mouse embryonic carcinoma-derived clonal cell line provides an in vitro model of chondrogenesis. Lactoferrin treatment of differentiating ATDC5 cells promoted cell proliferation in the initial stage of the differentiation process. However, lactoferrin treatment resulted in inhibition of hypertrophic differentiation, characterized by suppression of alkaline phosphatase activity, aggrecan synthesis and N-cadherin expression. This inhibitory effect was accompanied by sustained Sox9 expression, as well as increased Smad2/3 expression and phosphorylation, suggesting that lactoferrin regulates chondrogenic differentiation by up-regulating the Smad2/3-Sox9 signaling pathway.
Keywords: Hypertrophic differentiation; Aggrecan; Alkaline phosphatase; Sox9; Smad2/3; N-cadherin

Liposomalization of lactoferrin enhanced its anti-tumoral effects on melanoma cells by Anca Roseanu; Paula E. Florian; Magdalena Moisei; Livia E. Sima; Robert W. Evans; Mihaela Trif (485-492).
A number of studies have reported the anti-tumoral activity of lactoferrin, a property mediated by a variety of mechanisms such as inhibitory effects on tumor cell growth, NK cell activation, and enhancement of apoptosis. Liposomes are known to be an efficient drug delivery system which can enhance the therapeutic potential of the encapsulated compounds. We have used positively charged liposomes composed of phosphatidylcholine (PC), dioleoylphosphatidylethanolamine (DOPE), cholesterol (Chol) and stearylamine (SA) (6:1:2:1 M ratio) as a carrier system for bovine iron-free Lf (ApoBLf), and compared the in vitro effect of free and liposome-entrapped ApoBLf on the growth and morphology of murine melanoma B16-F10 cells. Liposomal formulation of ApoBLf was found to enhance the capacity of the protein to inhibit the cell proliferation by affecting cell cycle progression. The effect appeared to be due to the capacity of liposomes to increase the uptake of the protein and its accumulation into cells and probably to protect it from degradation, as revealed by fluorescence microscopy and flow cytometry. Our results demonstrate the ability of liposomes to improve the anti-tumor activity of Lf and suggest that liposomal protein may have a potential therapeutic use in the prevention and/or treatment of cancer diseases.
Keywords: Lactoferrin; Liposomes; Melanoma cells; Antitumoral

The human lactoferrin-derived peptide hLF1-11 primes monocytes for an enhanced TLR-mediated immune response by Anne M. van der Does; Sylvia J. P. Bogaards; Luigi Jonk; Marty Wulferink; Markwin P. Velders; Peter H. Nibbering (493-505).
Earlier we reported that the peptide corresponding to the first eleven N-terminal amino acids of human lactoferrin (hLF1-11) is active against multi-drug resistant pathogens in mice. The mechanisms underlying this anti-infective activity remain unclear. Since hLF1-11 is ineffective against pathogens at physiological salt concentrations and hLF1-11 directs differentiation of monocytes toward a macrophage subset with enhanced effector functions, we investigated the effects of hLF1-11 on human and murine monocytes. Results revealed that human and murine monocytes exposed for 1 h to hLF1-11 and then stimulated with the Toll-like receptor (TLR)-ligand LPS for 18 h, displayed enhanced cytokine and chemokine production as compared to control (peptide-treated) monocytes. We also found that expression of mRNA, cell-surface receptor expression, and NF-κB activation by hLF1-11-exposed human monocytes were enhanced as compared to control (peptide-treated) monocytes. Furthermore, the kinetics of the cytokine production was unchanged as mRNA levels and protein levels paralleled the enhanced response of hLF1-11-exposed monocytes to LPS. The cytokine production by human monocytes in response to TLR4, TLR5, and TLR7 stimulation, but not to TLR2 stimulation, was elevated by hLF1-11. In concordance, translocation of NF-κB subunits to the nucleus was enhanced in hLF1-11-exposed monocytes after TLR stimulation, except for TLR2, as compared to control (peptide-exposed) monocytes. In conclusion, monocytes were primed by hLF1-11 for an enhanced inflammatory response upon TLR4, TLR5, and TLR7 stimulation, but not TLR2 stimulation. Such effects of hLF1-11 on monocyte reactivity should be taken into account when considering the clinical development of this peptide for a therapeutic intervention in patients.
Keywords: Antimicrobial peptide; Lactoferrin; Monocytes; TLR; NF-κB

E2F1-directed activation of Bcl-2 is correlated with lactoferrin-induced apoptosis in Jurkat leukemia T lymphocytes by Shin-Hee Lee; Hye-Min Hwang; Chul-Woong Pyo; Dae Hyun Hahm; Sang-Yun Choi (507-514).
Lactoferrin (Lf) has been shown to control the proliferation of a variety of mammalian cells. Recently, we reported that human Lf induces apoptosis via a c-Jun N-terminal kinases (JNK)-associated Bcl-2 pathway that stimulates programmed cell death. In order to gain insight into the mechanism underlying Lf-triggered apoptotic features, we attempted to determine the mechanisms whereby the Lf-induced Bcl-2 family proteins exert their pro- or anti-apoptotic effects in Jurkat leukemia T lymphocytes. Treatment of the cells with high concentrations of Lf resulted in a significant reduction in in vitro growth and cell viability. As the levels of Lf increased, greater quantities of CDK6 and hyper-phosphorylated retinoblastoma protein were produced, resulting in the induction of E2F1-dependent apoptosis. Simultaneously, PARP and caspases were efficiently cleaved during Lf-induced apoptosis. The E2F1-induced apoptotic process occurred preferentially in p53-deficient Jurkat leukemia cells. Therefore, we attempted to determine whether E2F1-regulated Bcl-2 family proteins involved in the apoptotic process were relevant to Lf-induced apoptosis. We found that Lf increased the interaction of Bcl-2 with the pro-apoptotic protein Bad, whereas the total protein levels did not change significantly. Our results, collectively, suggest that Lf exploits the control mechanism of E2F1-regulated target genes or Bcl-2 family gene networks involved in the apoptotic process in Jurkat human leukemia T lymphocytes.
Keywords: Lactoferrin; Iron; Apoptosis; Jurkat; Bcl-2

Effect of bovine lactoferrin in Salmonella ser. Typhimurium infection in mice by Susan Mosquito; Theresa J. Ochoa; Jaime Cok; Thomas G. Cleary (515-521).
Lactoferrin (LF) has in vitro antimicrobial activity against Gram-negative bacteria. Salmonella enterica subsp. enterica serovar Typhimurium causes systemic infection and acute diarrhea in humans, mainly in children younger than 2 years of age. The aim of the study was to determine the in vivo effect of bovine LF in Salmonella ser. Typhimurium infection in mice. 58 BALB/c mice were employed. Two hours before the infection with 300 μl of 107 CFU of Salmonella ser. Typhimurium, 29 mice received LF (2 mg) and 29 placebo (buffer). After the infection, the mice received LF (10 mg/ml) ad libitum or buffer, respectively, for 7 days. Mortality, weight and clinical signs (piloerection, hunched position and reduced movement) were monitored daily. The degree of inflammation and necrosis in the intestine, liver, spleen and brain were studied with a blinded observer. The mortality in the control group (8/29) was higher than in the LF group (1/29) (Kapplan Meier P < 0.05). From the third day post-infection the control group were significantly more symptomatic (P < 0.05). The blood culture for Salmonella spp. was positive for all mice studied in the control group (17/17), but positive in the LF group in only 6/17 animals (P < 0.05). In the LF group, the pathologic studies show less inflammation and focal necrosis in the four organs studied, with the greatest difference found in the intestine. Bovine LF protects against Salmonella ser. Typhimurium infection in mice, reducing the severity, mortality and the degree of inflammation of this infection.
Keywords: Lactoferrin; Salmonella; Mice; Type three secretory system; Inflammation

Cloning, expression and characterization of Kunming mice lactoferrin and its N-lobe by Jiarong Wang; Zigang Tian; Da Teng; Yalin Yang; Jiancheng Hu; Jianhua Wang (523-530).
The lactoferrin cDNA of Kunming mice was isolated by reverse transcription polymerase chain reaction and cloned into vector pET28a(+). Its deduced amino acid sequence was analyzed and compared with lactoferrin of other species. Its secondary and tertiary structure are predicted and modeled by bioinformatics tools online. Then recombinant Kunming mice lactoferrin and its N-lobe were both expressed successfully in the Escherichia coli BL21(DE3) in the form of inclusion bodies. After purification with Ni–NTA His-Bind resin, the yield of recombinant lactoferrin was 17 mg l−1 with purity of 92.1%, and that of lactoferrin N-lobe was 20 mg l−1 with purity of 98.5%. The inhibition efficiency of refolded lactoferrin N-lobe against Staphylococcus aureus ATCC 25923 reaches 48.6% at the concentration of 25 μmol l−1. However, the refolded lactoferrin (12.5 μmol l−1) didn’t display obvious inhibition activity in the test. The expression of recombinant Kunming mice lactoferrin and its N-lobe will be helpful for the study of lactoferrin on structure, function and application in a mouse model system.
Keywords: Expression; Lactoferrin; N-lobe; Kunming mice; Escherichia coli

Bovine lactoferrin interacts with cable pili of Burkholderia cenocepacia by Maria Grazia Ammendolia; Lucia Bertuccini; Francesca Iosi; Fabio Minelli; Francesca Berlutti; Piera Valenti; Fabiana Superti (531-542).
In this study we evaluated the ability of lactoferrin, the most abundant antimicrobial protein in airway secretions, to bind the surface structures of a Burkholderia strain cystic fibrosis-isolated. Burkholderia cenocepacia is a gram-negative bacterium involved as respiratory pathogen in cystic fibrosis patient infections. This bacterium possesses filamentous structures, named cable pili that have been proposed as virulence factors because of their ability to bind to respiratory epithelia and mucin. Previously, we demonstrated that bovine lactoferrin was able to influence the efficiency of invasion of different iron-regulated morphological forms of B. cenocepacia. Bovine lactoferrin showed to efficiently inhibit invasion of alveolar epithelial cells by free-living bacteria or iron-induced aggregates or biofilm. Results of the present study demonstrate that bovine lactoferrin is also able to specifically bind to B. cenocepacia cells and show that cable pili are involved in this interaction. The attachment of bovine lactoferrin to pili led to a reduced binding of bacterial cells to mucin. Since cable pili are implicated in mediating the bacterial interactions with mucin and epithelial cells, lactoferrin binding to these structures could play an important role in neutralizing bacterial infection in cystic fibrosis patients.
Keywords: Bovine lactoferrin; Burkholderia cenocepacia ; Cable pili

Probiotic Lactobacillus casei Expressing Human Lactoferrin Elevates Antibacterial Activity in the Gastrointestinal Tract by Hsiao-Ling Chen; Yi-Wen Lai; Chua-Shun Chen; Te-Wei Chu; Willie Lin; Chih-Ching Yen; Ming-Fong Lin; Ming-Yu Tu; Chuan-Mu Chen (543-554).
In this study, Lactobacillus casei was used to deliver and express human lactoferrin (hLF) to protect the host against bacterial infection. Full-length hLF cDNA was cloned into a Lactobacillus-specific plasmid to produce the L. casei transformants (rhLF/L. casei). Antimicrobial activity of recombinant hLF was examined in inhibition of bacteria growth in vitro. A mouse model was established to test in vivo antibacterial activity and protective effect of orally-administered probiotic L. casei transformant in the gastrointestinal tract. Trials were conducted in which animals were challenged with E. coli ATCC25922. E. coli colony numbers in duodenal fluid from the group fed with rhLF/L. casei were significantly lower than those of the group fed with wild-type L. casei or placebo (P < 0.01). Histopathological analyses of the small intestine, showed both decreased intestinal injury and increased villi length were observed in the mice fed with rhLF/L. casei as compared with the control groups (P < 0.01). Our results demonstrate that L. casei expressing hLF exhibited antibacterial activity both in in vitro and in vivo. It also provides a potentially large-scale production of hLF as applications for treatment of infections caused by clinically relevant pathogens.
Keywords: Human lactoferrin; Lactobacillus casei ; Probiotics; Antibacterial activity; Gastrointestinal tract

Bovine lactoferricin (LfcinB) is a cationic peptide that selectively induces apoptosis in Jurkat cells. However less is known about the influence of this kind of apoptosis on the intra-cellular ceramide metabolism and the structure–function relationship between the loop structure of LfcinB and its action of inducing apoptosis in Jurkat cells. In the present study, the artificially synthesized LfcinB and LfcinB-derived peptide (Cys 19 residue in LfcinB was replaced by Ala) was added in Jurkat cells, the nucleolus shape was observed by fluorescent microscopy, the ceramide concentration in Jurkat cells was determined by reversed phase high performance liquid chromatography (RP-HPLC). The results of MTT assay showed that LfcinB inhibited proliferation of Jurkat cells, and the inhibition rate was approximately 18.90%. Moreover, the inhibition rate of LfcinB together with MAPP was upto approximately 59.89%. The RP-HPLC result showed that LfcinB improved the ceramide level in Jurkat cells. By using the DNA fragmentation assay and observing the nucleolus shape, the result displayed deficiency of the loop structure could cause LfcinB losing the biological activity of inducing apoptosis in Jurkat cells.
Keywords: Bovine lactoferricin; Structure–function relationship; Ceramide; Apoptosis; Jurkat cells

Microbicidal effect of the lactoferrin peptides Lactoferricin17–30, Lactoferrampin265–284, and Lactoferrin chimera on the parasite Entamoeba histolytica by Fernando López-Soto; Nidia León-Sicairos; Kamran Nazmi; Jan G. Bolscher; Mireya de la Garza (563-568).
Entamoeba histolytica is a parasitic protozoan that produces amoebiasis, an intestinal disease characterized by ulcerative colitis and dysentery. In some cases, trophozoites can travel to the liver leading to hepatic abscesses and death. Recently, lactoferrin and lactoferricin B have been shown to be amoebicidal in axenic cultures. The aim of this work was to determine whether the lactoferrin-peptides lactoferricin amino acids 17–30, lactoferrampin amino acids 265–284, and lactoferrin chimera which is a fusion product of the two peptides, are capable of producing a microbicidal effect to trophozoites of E. histolytica. We evaluated the killing effect of these peptides in growth kinetics carried out in axenic culture medium to which different concentrations of peptides were added. At 50 μM of peptide concentration, lactoferricin and lactoferrampin had a moderate amoebicidal effect, since a 45–50% of trophozoites remained viable at 24 h culture. However, at 50 μM of the lactoferrin chimera 75% amoeba were killed whereas at 100 μM all cells died. These data indicate that of lactoferrin-peptides mainly the chimera have amoebicidal activity in a time- and concentration-dependent manner. The lactoferrin-peptides might be useful as therapeutic agents against amoebiasis and thereby diminish the use of metronidazole, which is extremely toxic for the host.
Keywords: Entamoeba histolytica ; Amoebicidal effect; LFcin; LFampin; LFchimera

Bactericidal effect of bovine lactoferrin, LFcin, LFampin and LFchimera on antibiotic-resistant Staphylococcus aureus and Escherichia coli by Héctor Flores-Villaseñor; Adrian Canizalez-Román; Magda Reyes-Lopez; Kamram Nazmi; Mireya de la Garza; Jorge Zazueta-Beltrán; Nidia León-Sicairos; Jan G. M. Bolscher (569-578).
Increased prevalence of antibiotic-resistant bacteria has become a major threat to the health sector worldwide due to their virulence, limited therapeutic options and distribution in both hospital and community settings. Discovery and development of new agents to combat antibiotic-resistant bacteria is thus needed. This study therefore aimed to evaluate the ability of bovine lactoferrin (LF), peptides from two antimicrobial domains lactoferricin B (LFcin17-30) and lactoferrampin (LFampin265-284) and a chimeric construct (LFchimera) containing both peptides, as potential bactericidal agents against clinical isolates of antibiotic-resistant Staphylococcus aureus and Escherichia coli. Results in kinetics of growth show that LF chimera and peptides inhibited the growth of both bacterial species. By confocal microscopy and flow cytometry it was observed that LF and FITC-labeled peptides are able to interact with these bacteria and cause membrane permeabilization, as monitored by propidium iodide staining, these effects were decreased by preincubation with lipopolysaccharide in E. coli. By electron microscopy, a clear cellular damage was observed in bacteria after treatments with LFchimera and peptides, suggesting that interaction and membrane disruption are probably involved as a mechanism of action. In conclusion, results show that LFchimera, LF and peptides have potential as bactericidal agents in the antibiotic-resistant strains of S. aureus and E. coli and also the work strongly suggest that LFcin17-30 and LFampin265-284 acts synergistically with antibiotics against multidrug resistant EPEC and MRSA in vitro.
Keywords: Lactoferrin; Lactoferrin chimera; Peptides; Bactericidal; Resistance

Porcine lactoferrin as feedstuff additive elevates avian immunity and potentiates vaccination by Che-Ming Hung; Shinn-Chih Wu; Chih-Ching Yen; Ming-Fong Lin; Yi-Wen Lai; Yu-Tang Tung; Hsiao-Ling Chen; Chuan-Mu Chen (579-587).
In this study, recombinant porcine lactoferrin (PLF) was used as feedstuff additive to investigate the effects of peripheral lymphocyte proliferation and serum antibody titers in chickens vaccinated against the infectious bursal disease (IBD) virus. Treatment groups were fed three doses of PLF powder in their diet (0.5, 1.0, and 2.0% w/w), and the IBD vaccine was administrated at 1 and 3 weeks of age. At 8, 12, and 16 weeks after vaccination, serum IBD antibody titers were measured via the micro-method and T cell proliferation rates were evaluated. The results revealed that a high dose of PLF led to significant increases in serum IgA, IgG and IBD-specific antibody titers (P < 0.05). PLF administration, at either low or high doses, enhanced the expression of IFN-γ and IL-12 in chicken T lymphocytes. These results suggest that PLF enhances cell-mediated immunity and augment the ability of IBD vaccination to strengthen subsequent anti-viral responses.
Keywords: Porcine lactoferrin; Lymphocyte proliferation; Serum antibody titer; Cytokine; Infectious bursal disease (IBD); Vaccination

Lactoferrin is an iron-binding glycoprotein that exhibits a range of health benefits including immune regulation and disease prevention derived from its structural properties. The present study employed immune cell models and a colon epithelial cell model to investigate the protective effects of bovine lactoferrin (BLf) on both immune cells and colon epithelium cells. BLf caused significant reduction of faecal genotoxin-induced DNA damage in HT29 cells, and down-regulation of lipopolysaccharide (LPS)-induced macrophage cell stress and endotoxic response, in an infection status.
Keywords: Bovine lactoferrin; Cellular model system; DNA damage; Lipopolysaccharide; Faecal water

Influence of bovine lactoferrin on selected probiotic bacteria and intestinal pathogens by Hong Tian; Ian S. Maddox; Lynnette R. Ferguson; Quan Shu (593-596).
This study investigated the effects of bovine lactoferrin (BLf) on the growth of different groups of bacteria in vitro. BLf showed a significant inhibitory effect on the growth of selected pathogens but not probiotics. BLf, in combination with probiotics, has the potential to influence the composition of the gut microflora via inhibition of intestinal pathogens with no significant effect on probiotic bacteria.
Keywords: Bovine lactoferrin; Probiotics; Pathogens; Antibacterial activity