Unbiased Identification of Angiogenin as an Endogenous Antimicrobial Protein With Activity Against Virulent Mycobacterium tuberculosis

Abstract

Tuberculosis is a highly prevalent infectious disease with more than 1.5 million fatalities each year. Antibiotic treatment is available, but intolerable side effects and an increasing rate of drug-resistant strains of Mycobacterium tuberculosis (Mtb) may hamper successful outcomes. Antimicrobial peptides (AMPs) offer an alternative strategy for treatment of infectious diseases in which conventional antibiotic treatment fails. Human serum is a rich resource for endogenous AMPs. Therefore, we screened a library generated from hemofiltrate for activity against Mtb. Taking this unbiased approach, we identified Angiogenin as the single compound in an active fraction. The antimicrobial activity of endogenous Angiogenin against extracellular Mtb could be reproduced by synthetic Angiogenin. Using computational analysis, we identified the hypothetical active site and optimized the lytic activity by amino acid exchanges. The resulting peptide-Angie1-limited the growth of extra‐ and intracellular Mtb and the fast-growing pathogens Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Toward our long-term goal of evaluating Angie1 for therapeutic efficacy in vivo, we demonstrate that the peptide can be efficiently delivered into human macrophages via liposomes and is not toxic for zebrafish embryos. Taken together, we define Angiogenin as a novel endogenous AMP and derive the small, bioactive fragment Angie1, which is ready to be tested for therapeutic activity in animal models of tuberculosis and infections with fast-growing bacterial pathogens.

Multi-omics provide evidence for an anti-inflammatory immune signature and metabolic alterations in patients with Long COVID Syndrome – an exploratory study

“…Down-regulation of CD14 may thus indicate less M1-like macrophage responses in LCS patients. Angiogenin (ANG) is an angiogenic protein also described as anti-bacterial protein secreted by macrophages ( 26 ). Proteoglycan-4 (PRG4) is mainly expressed by fibroblast-like cells but serves as an important regulator of inflammation ( 27 ) and has been described to act as an essential regulator of synovial macrophage polarization and inflammatory macrophage joint infiltration ( 28 ).…”

“…The osmolyte taurine, which has been attributed with anti-inflammatory and anti-oxidative properties (36), was significantly increased in LCS patients compared to the other two groups. The metabolite most significantly up-regulated in LCS patients was hypaphorine (TrpBetaine), an anti-inflammatory alkaloid (25) described to induce sleep in mice (26), which might thus also relate to the chronic fatigue symptoms in LCS. Inversely, hypoxanthine levels, which are among others indicative of tissue hypoxia as found during acute inflammation, were strongly increased in the recovered group, while LCS patients showed similar levels to the healthy group.…”

Angiogenin and Copper Crossing in Wound Healing

“…In this review, we will focus on the role of the angiogenin protein, a potent endogenous angiogenic factor that exhibits antimicrobial properties and an ability to bind copper ions [ 22 , 23 , 24 ]. Copper is also a known angiogenic factor that regulates different steps of the wound healing process, including the expression of VEGF and ANG [ 25 , 26 ].…”

Gran1: A Granulysin-Derived Peptide with Potent Activity against Intracellular Mycobacterium tuberculosis

“…Live-dead staining (BacLight, Invitrogen, Carlsbad, CA, USA) of bacterial suspensions with fluorochromic substrates revealed a viability of the bacteria >90% [47]. Prior to use, thawed aliquots were sonicated in a water bath for 10 min at 40 kHz and 110 W at room temperature to disrupt small aggregates of bacteria [48].…”

“…For in vitro studies, 1 × 10 5 macrophages were incubated with Gran1 for 24 h in a 96-well plate, followed by an addition of 10% PrestoBlue (Thermo Fisher, Waltham, MA, USA) for 20 min. Reduction of the non-fluorescent resazurin-based PrestoBlue to fluorescent resorufin by mitochondrial enzymes of viable cells allowed for the calculation of cytotoxicity as described [48].…”