Human milk oligosaccharides regulate human macrophage polarization and activation in response to Staphylococcus aureus.

Human milk oligosaccharides (HMOs) are present in high numbers in milk of lactating women. They are beneficial to gut health and the habitant microbiota, but less is known about their effect on cells from the immune system. In this study, we investigated the direct effect of three structurally different HMOs on human derived macrophages before challenge with Staphylococcus aureus (S. aureus). The study demonstrates that individual HMO structures potently affect the activation, differentiation and development of monocyte-derived macrophages in response to S. aureus. 6´-Sialyllactose (6'SL) had the most pronounced effect on the immune response against S. aureus, as illustrated by altered expression of macrophage surface markers, pointing towards an activated M1-like macrophage-phenotype. Similarly, 6'SL increased production of the pro-inflammatory cytokines TNF-α, IL-6, IL-8, IFN-γ and IL-1ß, when exposing cells to 6'SL in combination with S. aureus compared with S. aureus alone. Interestingly, macrophages treated with 6'SL exhibited an altered proliferation profile and increased the production of the classic M1 transcription factor NF-κB. The HMOs also enhanced macrophage phagocytosis and uptake of S. aureus. Importantly, the different HMOs did not notably affect macrophage activation and differentiation without S. aureus exposure. Together, these findings show that HMOs can potently augment the immune response against S. aureus, without causing inflammatory activation in the absence of S. aureus, suggesting that HMOs assist the immune system in targeting important pathogens during early infancy.

Partial Substitution of Meat with Insect (Alphitobius diaperinus) in a Carnivore Diet Changes the Gut Microbiome and Metabolome of Healthy Rats.

Insects are suggested as a sustainable protein source of high nutritional quality, but the effects of insect ingestion on processes in the gastrointestinal tract and gut microbiota (GM) remain to be established. We examined the effects of partial substitution of meat with insect protein (Alphitobius diaperinus) in a four-week dietary intervention in a healthy rat model (n = 30). GM composition was characterized using' 16S rRNA gene amplicon profiling while the metabolomes of stomach, small intestine, and colon content, feces and blood were investigated by 1H-NMR spectroscopy. Metabolomics analyses revealed a larger escape of protein residues into the colon and a different microbial metabolization pattern of aromatic amino acids when partly substituting pork with insect. Both for rats fed a pork diet and rats fed a diet with partial replacement of pork with insect, the GM was dominated by Lactobacillus, Clostridium cluster XI and Akkermansia. However, Bray-Curtis dissimilarity metrics were different when insects were included in the diet. Introduction of insects in a common Western omnivore diet alters the gut microbiome diversity with consequences for endogenous metabolism. This finding highlights the importance of assessing gastrointestinal tract effects when evaluating new protein sources as meat replacements.

Rapid inflammation and early degeneration of bone and cartilage revealed in a time-course study of induced haemarthrosis in haemophilic rats.

OBJECTIVES: Detailed knowledge of the sequential cell and tissue responses following haemarthrosis is important for a deep understanding of the pathological process initiated upon extensive bleeding into the joint causing haemophilic arthropathy (HA). The underlying pathobiology driving haemarthrosis towards HA has been difficult to establish in detail, although animal models have shed light on some processes. Previous studies have focused on a single or a few distant time points and often only characterizing one tissue type of the joint. The objective of this study was, therefore, to carefully map early onset of synovitis and HA following induced haemarthrosis. METHODS: One hundred and thirty haemophilia A rats were subjected to induced haemarthrosis or a sham procedure in full anaesthesia and euthanized from 30 min to 7 days after the procedure. Pathological changes of the joints were visualized using micro-computed tomography, histology and immunohistochemistry. RESULTS: Synovitis developed within 24 h and was dominated by myeloid cell infiltrations. Cartilage and bone pathology were evident as early as 48-96 h after haemarthrosis, and the pathology rapidly progressed with extensive periosteal bone formation and formation of subchondral cysts. CONCLUSION: Fast, extensive and simultaneous cartilage and bone degeneration developed shortly after haemarthrosis, as shown by the detailed mapping of the early pathogenesis of HA. The almost immediate loss of cartilage and the pathological bone turnover suggest a direct influence of blood on these processes and are unlikely to be attributed simply to an indirect effect of inflammation.

The collagen receptor uPARAP/Endo180 as a novel target for antibody-drug conjugate mediated treatment of mesenchymal and leukemic cancers.

A key task in developing the field of personalized cancer therapy is the identification of novel molecular targets that enable treatment of cancers not susceptible to other means of specific therapy. The collagen receptor uPARAP/Endo180 is overexpressed by malignant cells in several non-epithelial cancers, notably including sarcomas, glioblastomas and subsets of acute myeloid leukemia. In contrast, in healthy adult individuals, expression is restricted to minor subsets of mesenchymal cells. Functionally, uPARAP/Endo180 is a rapidly recycling endocytic receptor that delivers its cargo directly into the endosomal-lysosomal system, thus opening a potential route of entry into receptor-positive cells. This combination of specific expression and endocytic function appears well suited for targeting of uPARAP/Endo180-positive cancers by antibody-drug conjugate (ADC) mediated drug delivery. Therefore, we utilized a specific monoclonal antibody against uPARAP/Endo180, raised through immunization of a uPARAP/Endo180 knock-out mouse, which reacts with both the human and the murine receptor, to construct a uPARAP-directed ADC. This antibody was coupled to the highly toxic dolastatin derivative, monomethyl auristatin E, via a cathepsin-labile valine-citrulline linker. With this ADC, we show strong and receptor-dependent cytotoxicity in vitro in uPARAP/Endo180-positive cancer cell lines of sarcoma, glioblastoma and leukemic origin. Furthermore, we demonstrate the potency of the ADC in vivo in a xenograft mouse model with human uPARAP/Endo180-positive leukemic cells, obtaining a complete cure of all tested mice following intravenous ADC treatment with no sign of adverse effects. Our study identifies uPARAP/Endo180 as a promising target for novel therapy against several highly malignant cancer types.