Broad Protection against Invasive Fungal Disease from a Nanobody Targeting the Active Site of Fungal ß-1,3-Glucanosyltransferases.

Invasive fungal disease accounts for about 3.8 million deaths annually, an unacceptable rate that urgently prompts the discovery of new knowledge-driven treatments. We report the use of camelid single-domain nanobodies (Nbs) against fungal ß-1,3-glucanosyltransferases (Gel) involved in ß-1,3-glucan transglycosylation. Crystal structures of two Nbs with Gel4 from Aspergillus fumigatus revealed binding to a dissimilar CBM43 domain and a highly conserved catalytic domain across fungal species, respectively. Anti-Gel4 active site Nb3 showed significant antifungal efficacy in vitro and in vivo prophylactically and therapeutically against different A. fumigatus and Cryptococcus neoformans isolates, reducing the fungal burden and disease severity, thus significantly improving immunocompromised animal survival. Notably, C. deneoformans (serotype D) strains were more susceptible to Nb3 and genetic Gel deletion than C. neoformans (serotype A) strains, indicating a key role for ß-1,3-glucan remodelling in C. deneoformans survival. These findings add new insight about the role of ß-1,3-glucan in fungal biology and demonstrate the potential of nanobodies in targeting fungal enzymes to combat invasive fungal diseases.

Selective Detection of Active Extracellular Granzyme A by Using a Novel Fluorescent Immunoprobe with Application to Inflammatory Diseases.

Granzymes (Gzms), a family of serine proteases, expressed by immune and nonimmune cells, present perforin-dependent and independent intracellular and extracellular functions. When released in the extracellular space, GzmA, with trypsin-like activity, is involved in the pathophysiology of different inflammatory diseases. However, there are no validated specific systems to detect active forms of extracellular GzmA, making it difficult to assess its biological relevance and potential use as a biomarker. Here, we have developed fluorescence-energy resonance-transfer (FRET)-based peptide probes (FAM-peptide-DABCYL) to specifically detect GzmA activity in tissue samples and biological fluids in both mouse and human samples during inflammatory diseases. An initial probe was developed and incubated with GzmA and different proteases like GzmB and others with similar cleavage specificity as GzmA like GzmK, thrombin, trypsin, kallikrein, or plasmin. After measuring fluorescence, the probe showed very good specificity and sensitivity for human and mouse GzmA when compared to GzmB, its closest homologue GzmK, and with thrombin. The specificity of this probe was further refined by incubating the samples in a coated plate with a GzmA-specific antibody before adding the probe. The results show a high specific detection of soluble GzmA even when compared with other soluble proteases with very similar cleavage specificity like thrombin, GzmK, trypsin, kallikrein, or plasmin, which shows nearly no fluorescence signal. The high specific detection of GzmA was validated, showing that using pure proteins and serum and tissue samples from GzmA-deficient mice presented a significant reduction in the signal compared with WT mice. The utility of this system in humans was confirmed, showing that GzmA activity was significantly higher in serum samples from septic patients in comparison with healthy donors. Our results present a new immunoprobe with utility to detect extracellular GzmA activity in different biological fluids, confirming the presence of active forms of the soluble protease in vivo during inflammatory and infectious diseases.

Multiparametric in vitro and in vivo analysis of the safety profile of self-assembling peptides.

Self-assembling peptides (SAPs) have gained significant attention in biomedicine because of their unique properties and ability to undergo molecular self-assembly driven by non-covalent interactions. By manipulating their composition and structure, SAPs can form well-ordered nanostructures with enhanced selectivity, stability and biocompatibility. SAPs offer advantages such as high chemical and biological diversity and the potential for functionalization. However, studies concerning its potentially toxic effects are very scarce, a limitation that compromises its potential translation to humans. This study investigates the potentially toxic effects of six different SAP formulations composed of natural amino acids designed for nervous tissue engineering and amenable to ready cross-linking boosting their biomechanical properties. All methods were performed in accordance with the relevant guidelines and regulations. A wound-healing assay was performed to evaluate how SAPs modify cell migration. The results in vitro demonstrated that SAPs did not induce genotoxicity neither skin sensitization. In vivo, SAPs were well-tolerated without any signs of acute systemic toxicity. Interestingly, SAPs were found to promote the migration of endothelial, macrophage, fibroblast, and neuronal-like cells in vitro, supporting a high potential for tissue regeneration. These findings contribute to the development and translation of SAP-based biomaterials for biomedical applications.

CAR Immunotherapy for the treatment of infectious diseases: a systematic review.

Immunotherapy treatments aim to modulate the host's immune response to either mitigate it in inflammatory/autoimmune disease or enhance it against infection or cancer. Among different immunotherapies reaching clinical application during the last years, chimeric antigen receptor (CAR) immunotherapy has emerged as an effective treatment for cancer where different CAR T cells have already been approved. Yet their use against infectious diseases is an area still relatively poorly explored, albeit with tremendous potential for research and clinical application. Infectious diseases represent a global health challenge, with the escalating threat of antimicrobial resistance underscoring the need for alternative therapeutic approaches. This review aims to systematically evaluate the current applications of CAR immunotherapy in infectious diseases and discuss its potential for future applications. Notably, CAR cell therapies, initially developed for cancer treatment, are gaining recognition as potential remedies for infectious diseases. The review sheds light on significant progress in CAR T cell therapy directed at viral and opportunistic fungal infections.

Fluorogenic Granzyme A Substrates Enable Real-Time Imaging of Adaptive Immune Cell Activity.

Cytotoxic immune cells, including T lymphocytes (CTLs) and natural killer (NK) cells, are essential components of the host response against tumors. CTLs and NK cells secrete granzyme A (GzmA) upon recognition of cancer cells; however, there are very few tools that can detect physiological levels of active GzmA with high spatiotemporal resolution. Herein, we report the rational design of the near-infrared fluorogenic substrates for human GzmA and mouse GzmA. These activity-based probes display very high catalytic efficiency and selectivity over other granzymes, as shown in tissue lysates from wild-type and GzmA knock-out mice. Furthermore, we demonstrate that the probes can image how adaptive immune cells respond to antigen-driven recognition of cancer cells in real time.