Whey proteins have beneficial effects on intestinal enteroendocrine cells stimulating cell growth and increasing the production and secretion of incretin hormones

Whey protein has been indicated to curb diet-induced obesity, glucose intolerance and delay the onset of type 2 diabetes mellitus. Here the effects of intact crude whey, intact individual whey proteins and beta-lactoglobulin hydrolysates on an enteroendocrine (EE) cell model were examined. STC-1 pGIP/neo cells were incubated with several concentrations of yogurt whey (YW), cheese whey (CW), beta-lactoglobulin (BLG), alpha-lactalbumin (ALA) and bovine serum albumin (BSA). The findings demonstrate that BLG stimulates EE cell proliferation, and also GLP-1 secretion (an effect which is lost following hydrolysis with chymotrypsin or trypsin). ALA is a highly potent GLP-1 secretagogue which also increases the intracellular levels of GLP-1. Conversely, whey proteins and hydrolysates had little impact on GIP secretion. This appears to be the first investigation of the effects of the three major proteins of YW and CW on EE cells. The anti-diabetic potential of whey proteins should be further investigated.

A role for whey acidic protein four-disulfide-core 12 (WFDC12) in the regulation of the inflammatory response in the lung

Introduction: Secretory leucocyte protease inhibitor and elafin are members of the whey acidic protein (WAP), or WAP four disulfide-core (WFDC), family of proteins and have multiple contributions to innate defence including inhibition of neutrophil serine proteases and inhibition of the inflammatory response to lipopolysaccharide (LPS). This study aimed to explore potential activities of WFDC12, a previously uncharacterised WFDC protein expressed in the lung. Methods: Recombinant expression and purification of WFDC12 were optimised in Escherichia coli. Antiprotease, antibacterial and immunomodulatory activities of recombinant WFDC12 were evaluated and levels of endogenous WFDC12 protein were characterised by immunostaining and ELISA. Results: Recombinant WFDC12 inhibited cathepsin G, but not elastase or proteinase-3 activity. Monocytic cells pretreated with recombinant WFDC12 before LPS stimulation produced significantly lower levels of the pro-inflammatory cytokines interleukin-8 and monocyte chemotactic protein-1 compared with cells stimulated with LPS alone. Recombinant WFDC12 became conjugated to fibronectin in a transglutaminase-mediated reaction and retained antiprotease activity. In vivo WFDC12 expression was confirmed by immunostaining of human lung tissue sections. WFDC12 levels in human bronchoalveolar lavage fluid from healthy and lung-injured patients were quantitatively compared, showing WFDC12 to be elevated in both patients with acute respiratory distress syndrome and healthy subjects treated with LPS, relative to healthy controls. Conclusions: Together, these results suggest a role for this lesser known WFDC protein in the regulation of lung inflammation.

Targeting translocator protein (18 kDa) (TSPO) dampens pro-inflammatory microglia reactivity in the retina and protects from degeneration

BACKGROUND: Reactive microglia are commonly seen in retinal degenerative diseases, and neurotoxic microglia responses can contribute to photoreceptor cell death. We and others have previously shown that translocator protein (18 kDa) (TSPO) is highly induced in retinal degenerations and that the selective TSPO ligand XBD173 (AC-5216, emapunil) exerts strong anti-inflammatory effects on microglia in vitro and ex vivo. Here, we investigated whether targeting TSPO with XBD173 has immuno-modulatory and neuroprotective functions in two mouse models of acute retinal degeneration using bright white light exposure.

METHODS: BALB/cJ and Cx3cr1 (GFP/+) mice received intraperitoneal injections of 10 mg/kg XBD173 or vehicle for five consecutive days, starting 1 day prior to exposure to either 15,000 lux white light for 1 h or 50,000 lux focal light for 10 min, respectively. The effects of XBD173 treatment on microglia and Müller cell reactivity were analyzed by immuno-stainings of retinal sections and flat mounts, fluorescence-activated cell sorting (FACS) analysis, and mRNA expression of microglia markers using quantitative real-time PCR (qRT-PCR). Optical coherence tomography (OCT), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) stainings, and morphometric analyses were used to quantify the extent of retinal degeneration and photoreceptor apoptosis.

RESULTS: Four days after the mice were challenged with bright white light, a large number of amoeboid-shaped alerted microglia appeared in the degenerating outer retina, which was nearly completely prevented by treatment with XBD173. This treatment also down-regulated the expression of TSPO protein in microglia but did not change the TSPO levels in the retinal pigment epithelium (RPE). RT-PCR analysis showed that the microglia/macrophage markers Cd68 and activated microglia/macrophage whey acidic protein (Amwap) as well as the pro-inflammatory genes Ccl2 and Il6 were reduced after XBD173 treatment. Light-induced degeneration of the outer retina was nearly fully blocked by XBD173 treatment. We further confirmed these findings in an independent mouse model of focal light damage. Retinas of animals receiving XBD173 therapy displayed significantly more ramified non-reactive microglia and more viable arrestin-positive cone photoreceptors than vehicle controls.

CONCLUSIONS: Targeting TSPO with XBD173 effectively counter-regulates microgliosis and ameliorates light-induced retinal damage, highlighting a new pharmacological concept for the treatment of retinal degenerations.

Eppin: A Novel Protein Possessing Antimicrobial Properties Against Oral Pathogens

Background: Epididymal protease inhibitor (eppin) is a dual motif protein belonging to the whey acidic protein (WAP) family. Although expressed in numerous different tissues, to date, its functional characterisation is limited. It has been shown to exhibit antibacterial activity against Gram-negative bacteria (Escherichia coli) and antiprotease activity against some proteases of the serine protease family. We are interested in determining the role of eppin in innate immune defence. Objectives: This study aims to determine eppin's potential function in the innate immune response in the oral cavity by investigating the antimicrobial activity of eppin against relevant oral pathogens. Methods: Eppin was recombinantly expressed in E. coli cells and purified by immobilised metal affinity chromatography (IMAC). The antimicrobial effects of the protein were then assessed against two oral pathogens, Fusobacterium nucleatum and Candida albicans, using a double layer radial diffusion assay. Results: Eppin displayed antimicrobial activities against both oral pathogens tested and these activities were shown to be comparable to the well characterised antimicrobial peptide, LL-37. The antifungal effects of eppin were shown to be more potent than those of the human cathelicidin, LL-37. Conclusions: Eppin has been shown to possess both antibacterial and antifungal properties against oral pathogens, suggesting an important role for this protein in the innate immune response in the oral cavity. This study furthers our knowledge of the physiological role exerted by eppin and its possible role in the modulation of chronic diseases such as periodontitis and oral candidiasis.