Pasteur Institute of Iran

The increasing prevalence of highly antibiotic-resistant pathogen Pseudomonas aeruginosa, necessitates the exploration of novel therapeutic alternatives. This study aimed to isolate and characterize a bacteriophage with potential applications against P. aeruginosa wound infection.

The lytic phage ZAM-Pa99 was isolated from hospital sewage and subjected to comprehensive analysis, including morphological characterization, physicochemical properties, growth dynamics, biofilm degradation, genome sequencing, and bioinformatics analysis. ZAM-Pa99 was classified as a newly characterized isolate within the Pbunavirus genus, demonstrating a broad lytic host range (80% efficacy) against the tested clinical strains. This result aligns with in silico host-range predictions, which reflect the high sequence similarity of its receptor-binding proteins with those of relatedPbunavirus phages. Genomic analysis (65,139 bp) was crucial for identifying its therapeutic safety profile, confirming the absence of virulence factors or antimicrobial resistance genes. Importantly, multi-tool proteomic analysis resolved a canonical lysis cassette including a confirmed endolysin, a holin candidate and an identified tailspike-like receptor-binding protein with strong putative depolymerase activity. This mechanism correlated with functional results: ZAM-Pa99 achieved up to 95% degradation of 1-day-old P. aeruginosa biofilms, maintaining high efficacy against 3- and 5-day-old mature structures, results that were quantified and visually confirmed.

ZAM-Pa99's promising characteristics, including its broad host range, biofilm-degrading ability, and lack of harmful genes, make it a promising candidate for phage-based therapy against P. aeruginosa infections. These findings contribute to a growing body of evidence supporting the potential of bacteriophages as valuable nature's weapons for combating antibiotic-resistant pathogens.

Mycobacterium tuberculosis infects one-fourth of the global population, and current challenges such as latent infections, multidrug-resistant strains, and the limited efficacy of the BCG vaccine emphasize the urgent need for next-generation vaccines. This study aimed to introduce novel vaccine candidates, immunoreactive epitopes, and a novel multi-epitope vaccine (MEV).

New immunogenic targets were identified based on different characteristics, including subcellular localization, antigenicity, non-similarity to the host proteome, sequence conservation, prevalence, and B-cell and T-cell epitopes. In the next step, IFN-γ releasing immunoreactive epitopes with a high similarity to TCR-interacting epitopes were identified. The MEV was generated using shortlisted epitopes and the C-terminal fragment of Clostridium perfringens enterotoxin (CPE). Finally, the interactions of MEV epitopes with human MHC I and MHC II alleles were investigated.

In the first step, a total of seven proteins with desired immunogenic properties were introduced as novel immunogenic targets. Comparison of surface-exposed proteins to 4718 immunoreactive linear B-cell epitopes of M. tuberculosis resulted in identification of 719 non-redundant immunoreactive epitopes. Finally, seven immunoreactive, IFN-γ releasing epitopes with significant homology to TCR binding epitopes were employed to design a MEV. This MEV showed desirable structural and immunogenic properties. Moreover, it revealed promising interactions with human MHC I and MHC II alleles in molecular docking.

This study suggests PE/PPE proteins and TCR-recognized immunoreactive peptides as promising vaccine components against tuberculosis. In addition, the designed MEV with the C-terminal fragment of CPE may represent a potential candidate for future development as a mucosal vaccine against M. tuberculosis .

This study investigated whether photobiomodulation (PBM) preconditioning at 650 nm or 810 nm modifies the regenerative potential of exosomes secreted by human adipose-derived stem cells (HADSCs) during full-thickness acute skin wound healing in rats. Although both wavelengths have been shown to enhance ADSC viability, proliferation, and exosome release in vitro, their in vivo reparative efficacy remains incompletely defined. We had 4 groups: untreated controls, animals treated with exosomes from non-preconditioned HADSCs, and two groups receiving exosomes derived from HADSCs exposed to either 650-nm or 810-nm PBM. Exosomes were administered at a concentration of 150 μg/mL and a total dose of 450 μg per animal. Wound tissues were harvested on day 8 for biomechanical testing, stereological evaluation of tissue components, and analysis of miR-21, VEGF-A, and HIF-1α expression. The EXO 650, and EXO 810 groups demonstrated 119%, and 105% increases in Stress High Load capacity compared to control group (both p < 0.001). The EXO 650 and EXO 810 wavelengths resulted in 58% and 67% increase in fibroblast population (p < 0.01, p < 0.001). EXO 650 and EXO 810 wavelengths showed 43%, and 64% increases in the number of new blood vessels (p < 0.01, p < 0.001) over control values. Molecular signaling analysis via fold-change quantification indicates that Exo 650 and Exo 810 wavelengths achieved 1.65-fold, and 1.55-fold increases in VEGF-A expression relative to the control group (p < 0.001, p < 0.01). For miR-21, the Exo 650 and Exo 810 wavelengths achieved 1.45-fold, and 1.4-fold increases (both p < 0.001). In conclusion, Exosomes from HADSCs preconditioned with 650 or 810 nm PBM accelerated the proliferative phase of wound healing, improving biomechanical strength, fibroblast density, and angiogenesis versus controls. These effects were associated with reduced inflammation and upregulation of the miR-21/VEGF-A/HIF-1α axis. No significant differences were observed between the two wavelengths.