One-step isolation of lactoferrin using immobilized monoclonal antibodies

Precision engineered peptide targeting leukocyte extracellular traps mitigate acute kidney injury in Crush syndrome

Crush syndrome induced by skeletal muscle compression causes fatal rhabdomyolysis-induced acute kidney injury (RIAKI) that requires intensive care, including hemodialysis. However, access to crucial medical supplies is highly limited while treating earthquake victims trapped under fallen buildings, lowering their chances of survival. Developing a compact, portable, and simple treatment method for RIAKI remains an important challenge. Based on our previous finding that RIAKI depends on leukocyte extracellular traps (ETs), we aimed to develop a novel medium-molecular-weight peptide to provide clinical treatment of Crush syndrome. We conducted a structure-activity relationship study to develop a new therapeutic peptide. Using human peripheral polymorphonuclear neutrophils, we identified a 12-amino acid peptide sequence (FK-12) that strongly inhibited neutrophil extracellular trap (NET) release in vitro and further modified it by alanine scanning to construct multiple peptide analogs that were screened for their NET inhibition ability. The clinical applicability and renal-protective effects of these analogs were evaluated in vivo using the rhabdomyolysis-induced AKI mouse model. One candidate drug [M10Hse(Me)], wherein the sulfur of Met10 is substituted by oxygen, exhibited excellent renal-protective effects and completely inhibited fatality in the RIAKI mouse model. Furthermore, we observed that both therapeutic and prophylactic administration of M10Hse(Me) markedly protected the renal function during the acute and chronic phases of RIAKI. In conclusion, we developed a novel medium-molecular-weight peptide that could potentially treat patients with rhabdomyolysis and protect their renal function, thereby increasing the survival rate of victims affected by Crush syndrome.

Separation Technologies for Whey Protein Fractionation

Whey is a by-product of cheese, casein, and yogurt manufacture. It contains a mixture of proteins that need to be isolated and purified to fully exploit their nutritional and functional characteristics. Protein-enriched fractions and highly purified proteins derived from whey have led to the production of valuable ingredients for many important food and pharmaceutical applications. This article provides a review on the separation principles behind both the commercial and emerging techniques used for whey protein fractionation, as well as the efficacy and limitations of these techniques in isolating and purifying individual whey proteins. The fractionation of whey proteins has mainly been achieved at commercial scale using membrane filtration, resin-based chromatography, and the integration of multiple technologies (e.g., precipitation, membrane filtration, and chromatography). Electromembrane separation and membrane chromatography are two main emerging techniques that have been developed substantially in recent years. Other new techniques such as aqueous two-phase separation and magnetic fishing are also discussed, but only a limited number of studies have reported their application in whey protein fractionation. This review offers useful insights into research directions and technology screening for academic researchers and dairy processors for the production of whey protein fractions with desired nutritional and functional properties.

Total Knee Arthroplasty with a Ti6Al4V/PEEK Prosthesis on an Osteoarthritis Rat Model: Behavioral and Neurophysiological Analysis

Arthroplasty is a surgical procedure to restore the function of the joint of patient suffering from knee osteoarthritis. However, postoperative functional deficits are reported even after a rehabilitation program. In order to determine the origin of functional deficits of patient suffering from knee osteoarthritis and total knee arthroplasty, we developed a rodent model including a chemically-induced-osteoarthritis and designed a knee prosthesis (Ti6Al4V/PEEK) biomechanically and anatomically adapted to rat knee joint. Dynamic Weight-Bearing, gait kinematics, H-reflex from vastus medialis muscle and activities from metabosensitive III and IV afferent fibers in femoral nerve were assessed at 1 and 3 months post-surgery. Results indicate that knee osteoarthritis altered considerably the responses of afferent fibers to their known activators (i.e., lactic acid and potassium chloride) and consequently their ability to modulate the spinal sensorimotor loop, although, paradoxically, motor deficits seemed relatively light. On the contrary, results indicate that, after the total knee arthroplasty, the afferent responses and the sensorimotor function were slightly altered but that motor deficits were more severe. We conclude that neural changes attested by the recovery of the metabosensitive afferent activity and the sensorimotor loop were induced when a total knee replacement was performed and that these changes may disrupt or delay the locomotor recovery.

Lactoferrin and cancer disease prevention

Lactoferrin (LF) is an iron-binding glycoprotein that is composed of the transferrin family and is predominantly found in the products of the exocrine glands located in the gateways of the digestive, respiratory, and reproductive systems, suggesting a role in the non-specific defence against invading pathogens. Additionally, several physiological roles have been attributed to LF, namely regulation of iron homeostasis, host defence against infection and inflammation, regulation of cellular growth, and differentiation and protection against cancer development and metastasis. These findings have suggested LF's great potential therapeutic use in cancer disease prevention and/or treatment, namely as a chemopreventive agent. This review looks at the recent advances in understanding the mechanisms underlying the multifunctional roles of LF and future perspectives on its potential therapeutic applications.

Recovery of Lactoferrin and Lactoperoxidase from Sweet Whey Using Colloidal Gas Aphrons (CGAs) Generated from an Anionic Surfactant, AOT

The recovery of lactoferrin and lactoperoxidase from sweet whey was studied using colloidal gas aphrons (CGAs), which are surfactant-stabilized microbubbles (10-100 microm). CGAs are generated by intense stirring (8000 rpm for 10 min) of the anionic surfactant AOT (sodium bis-2-ethylhexyl sulfosuccinate). A volume of CGAs (10-30 mL) is mixed with a given volume of whey (1-10 mL), and the mixture is allowed to separate into two phases: the aphron (top) phase and the liquid (bottom) phase. Each of the phases is analyzed by SDS-PAGE and surfactant colorimetric assay. A statistical experimental design has been developed to assess the effect of different process parameters including pH, ionic strength, the concentration of surfactant in the CGAs generating solution, the volume of CGAs and the volume of whey on separation efficiency. As expected pH, ionic strength and the volume of whey (i.e. the amount of total protein in the starting material) are the main factors influencing the partitioning of the Lf.Lp fraction into the aphron phase. Moreover, it has been demonstrated that best separation performance was achieved at pH = 4 and ionic strength = 0.1 mol/L i.e., with conditions favoring electrostatic interactions between target proteins and CGAs (recovery was 90% and the concentration of lactoferrin and lactoperoxidase in the aphron phase was 25 times higher than that in the liquid phase), whereas conditions favoring hydrophobic interactions (pH close to pI and high ionic strength) led to lower performance. However, under these conditions, as confirmed by zeta potential measurements, the adsorption of both target proteins and contaminant proteins is favored. Thus, low selectivity is achieved at all of the studied conditions. These results confirm the initial hypothesis that CGAs act as ion exchangers and that the selectivity of the process can be manipulated by changing main operating parameters such as type of surfactant, pH and ionic strength.

Separation of alpha-lactalbumin and beta-lactoglobulin using membrane ultrafiltration

There is considerable commercial interest in the preparation of individual whey proteins as high-value food additives, nutraceuticals, and therapeutics. This study examined the use of membrane filtration for the separation of alpha-lactalbumin and beta-lactoglobulin. Stirred cell filtration experiments were performed using both cellulosic and polyethersulfone membranes to determine the optimal pH, ionic strength, and filtration conditions. Selectivities of greater than 55 could be achieved at pH 5.5 and 50 mM ionic strength using a 30-kD cellulose membrane. A diafiltration process was then designed for the protein separation. A 16-diavolume filtration yielded beta-lactoglobulin as the retentate product with a purification factor of 100 and recovery of 90%. The alpha-lactalbumin was recovered in the filtrate with a purification factor of more than 10 and nearly 99% yield. Model calculations were in good agreement with the experimental data.

On the molecular interaction between lactoferrin and the dye Red HE-3b. A novel approach for docking a charged and highly flexible molecule to protein surfaces

Lactoferrin (Lf) is a non-heme, iron binding protein present in many physiological fluids of vertebrates where its main role is the microbicidal activity. It has been isolated by different methods, including dye-affinity chromatography. Red HE-3B is one of the most common triazinic dyes applied in protein purification, but scant knowledge is available on structural details and on the energetics of its interaction with proteins. In this work we present a computational approach useful for identifying possible binding sites for Red HE-3B in apo and holo forms of Lfs from human and bovine source. A new geometrical description of Red HE-3B is introduced which greatly simplifies the conformational analysis. This approach proved to be of particular advantage for addressing conformational ensembles of highly flexible molecules. Predictions from this analysis were correlated with experimentally observed dye-binding sites, as mapped by protection from proteolysis in Red HE-3B/Lf complexes. This method could bear relevance for the screening of possible dye-binding sites in proteins whose structure is known and as a potential tool for the design of engineered protein variants which could be purified by dye-affinity chromatography.

Isolation and characterization of immunoglobulin in yolk (IgY) specific against hen egg white lysozyme by immunoaffinity chromatography

Six hens were intramuscularly (im) immunized once a week for 3 weeks using chicken egg white lysozyme (LS) as antigen. Antibody (immunoglobulin in yolk, IgY) ELISA values of 10(3)-fold diluted yolk were almost as high as 1.879 in the sixth week and maintained a value of 0.756 in the eighth week after the initial immunization treatment. The purification efficiency (specific activity of purified IgY against LS/specific activity of antibody in yolk against LS) of IgY specific against LS isolated by laboratory-prepared LS-bound (IgY-) Sepharose 4 Fast Flow immunoaffinity column was approximately 3380. By applying various amounts (0-22 mg) of the thusly obtained IgY specific against LS to the immunoaffinity column, the binding capacity (q(m)) and dissociation constant (K(d), M(-1)) of such immunoaffinity gel for IgY against LS were found to be 0.68 mg of IgY/mL of wet gel (0.54 mg of IgY/mg of LS) and 7.13 x 10(-6) M, respectively, as determined by Langmuir-type adsorption isotherms.

Lactoferrin-mediated protection of the host from murine cytomegalovirus infection by a T-cell-dependent augmentation of natural killer cell activity

The administration of bovine lactoferrin (LF) with 1 mg/g body weight before the murine cytomegalovirus (MCMV) infection completely protected the BALB/c mice from death due to the infection. In these LF-treated mice, a significant increase in the activity was found in the NK cells but not in the cytolytic T lymphocytes which recognized an MCMV-derived peptide. Moreover, the elimination of the NK cell activity by an injection with anti-asialo GM1 antibody abrogated such augmented resistance, thus supporting the hypothesis that the LF-mediated antiviral effect in vivo is performed through the augmentation of NK cell activity. No such LF-mediated antiviral effect in vivo with the increased NK cell activity was found in athymic nude mice, whereas it was restored completely by the transfer of splenic T cells from LF-treated donors. These findings therefore suggest that T lymphocytes induce both the augmentation of NK cell activity and the resultant antiviral effect in the LF-treated hosts.

Whey protein concentrates and isolates: processing and functional properties

Substantial progress has been made in understanding the basic chemical and structural properties of the principal whey proteins, that is, beta-lactoglobulin (beta-Lg), alpha-lactalbumin (alpha-La), bovine serum albumin (BSA), and immunoglobulin (Ig). This knowledge has been acquired in terms of: (1) procedures for isolation, purification, and characterization of the individual whey proteins in buffer solutions; and (2) whey fractionation technologies for manufacturing whey protein concentrates (WPC) with improved chemical and functional properties in food systems. This article is a critical review of selected publications related to (1) whey fractionation technology for manufacturing WPC and WPI; (2) fundamental properties of whey proteins; and (3) factors that affect protein functionality, that is, composition, protein structure, and processing.

Ovine lactoferrin: isolation from colostrum and characterization

Highly purified lactoferrin was isolated from ovine colostrum by sequential purification on CM-Sephadex C-50 and Blue-Sepharose, with overall yield of 55%. The ovine lactoferrin was characterized by SDS-PAGE, its amino acid composition and N-terminal sequence to residue 30. Homology with bovine and human lactoferrins was greater than 80 and 50% respectively. Antibodies to ovine lactoferrin were raised in rabbits and used to develop an enzyme-linked immunosorbent assay (ELISA). The antiserum was not cross reactive with other colostrum proteins.

Interacting properties of bovine lactoferrin with immobilized cibacron blue F3GA in column chromatography

Bovine lactoferrin, isolated from colostral milk, interacted strongly with immobilized Cibacron blue F3GA column. Lactoferrin, adsorbed on the dye column, could not be eluted by 8 M urea, 1% Triton X-100, and 75% ethylene glycol, but was eluted by .1 M sodium hydroxide, 1 M potassium thiocyanate, 3 M potassium chloride, and free Cibacron blue F3GA. Electrostatic forces between the sulfonic groups of Cibacron blue F3GA and the basic side-chain groups in lactoferrin molecule probably are responsible for the observed interaction. The elution profile for lactoferrin differed from those of lactoperoxidase and serum albumin, which might allow efficient isolation of lactoferrin from whey via affinity chromatography.