Modified CLEC3A-Derived Antimicrobial Peptides Lead to Enhanced Antimicrobial Activity against Drug-Resistant Bacteria.

Antimicrobial peptides (AMPs) represent a promising alternative to conventional antibiotics. Sequence changes can significantly improve the therapeutic properties of antimicrobial peptides. In our study, we apply different sequence modifications to enhance the performance of the CLEC3A-derived AMPs HT-16 and HT-47. We truncated their sequences, inserting a triple-glycine linker, adding an N-terminal tryptophan residue, and generating a D-amino acid variant, resulting in the generation of seven new peptides. We investigated their antimicrobial activity against gram-positive and gram-negative bacteria, their cytotoxicity to murine cells, and the biostability of the modified peptides in serum. We identified a novel antimicrobial peptide, WRK-30, with enhanced antimicrobial potency against S. aureus and MRSA. Additionally, WRK-30 was less cytotoxic to eukaryotic cells, allowing its application in higher concentrations in an in vivo setting. In conclusion, we identified a novel CLEC3A-derived antimicrobial peptide WRK-30 with significantly improved therapeutic properties and the potential to widen the repertoire of conventional antibiotics.

Measuring capillary blood glucose concentration: Is the first blood drop really the right blood drop?

BACKGROUND: Capillary blood glucose (CBG) is fundamental for diabetes mellitus management. However, it is still unclear whether the first or the subsequent blood drops most accurately reflect patients' blood glucose levels. METHODS: 128 healthy volunteers were included in this prospective cohort study from November 2021 to December 2021. Capillary blood glucose concentrations of the first four blood drops, measured using glucose meters were compared with venous blood concentrations of the respective donors, measured using an in-lab hexokinase method. ANOVA, the Spearman correlation coefficient and Bland-Altman plots were used to analyze the data. RESULTS: The mean plasma glucose concentration was 90.46 mg/dl with an SD of ± 14.416 (5.02 ± 0.8 mmol/l). There were statistically strong correlations among the glucose concentrations of all capillary blood drops (correlation coefficients of r > 0.8). The first capillary blood drops showed the lowest mean difference to plasma blood glucose concentrations (+4.92 mg/dl; +0.27 mmol/l), followed by the third drop (+7.28 mg/dl; +0.4 mmol/l), second drop (+7.30 mg/dl; +0.4 mmol/l) and fourth drop (+8.87 mg/dl; +0.49 mmol/l). CONCLUSION: There is a strong correlation and good agreement between the different capillary blood drops, making all blood drops equally suitable for blood glucose monitoring. In practice, the given setting (clinical or patient self-monitoring) should be considered upon choosing a specific blood drop.

The cartilage-specific lectin C-type lectin domain family 3 member A (CLEC3A) enhances tissue plasminogen activator-mediated plasminogen activation.

C-type lectin domain family 3 member A (CLEC3A) is a poorly characterized protein belonging to the superfamily of C-type lectins. Its closest homologue tetranectin binds to the kringle 4 domain of plasminogen and enhances its association with tissue plasminogen activator (tPA) thereby enhancing plasmin production, but whether CLEC3A contributes to plasminogen activation is unknown. Here, we recombinantly expressed murine and human full-length CLEC3As as well as truncated forms of CLEC3A in HEK-293 Epstein-Barr nuclear antigen (EBNA) cells. We analyzed the structure of recombinant CLEC3A by SDS-PAGE and immunoblot, glycan analysis, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, size-exclusion chromatography, circular dichroism spectroscopy, and electron microscopy; compared the properties of the recombinant protein with those of CLEC3A extracted from cartilage; and investigated its tissue distribution and extracellular assembly by immunohistochemistry and immunofluorescence microscopy. We found that CLEC3A mainly occurs as a monomer, but also forms dimers and trimers, potentially via a coiled-coil α-helix. We also noted that CLEC3A can be modified with chondroitin/dermatan sulfate side chains and tends to oligomerize to form higher aggregates. We show that CLEC3A is present in resting, proliferating, and hypertrophic growth-plate cartilage and assembles into an extended extracellular network in cultures of rat chondrosarcoma cells. Further, we found that CLEC3A specifically binds to plasminogen and enhances tPA-mediated plasminogen activation. In summary, we have determined the structure, tissue distribution, and molecular function of the cartilage-specific lectin CLEC3A and show that CLEC3A binds to plasminogen and participates in tPA-mediated plasminogen activation.