Di Pietro, C. | bioRxiv Science

bioRxiv2026

An N, S-acetylated L-cysteine-cysteamine conjugate hinders pyocyanin redox cycling to weaken Pseudomonas aeruginosa biofilm and dampens LPS-driven acute pulmonary inflammation

The persistence of P. aeruginosa infections is largely driven by the secretion of several factors during invasion, including the redox-active phenazine pyocyanin (PYO), which promotes biofilm formation and oxidative stress. Biofilms contribute to chronic infections and antibiotic resistance, limiting the efficacy of conventional therapies. We found that a synthetic compound, I-152, a conjugate of N-acetyl-L-cysteine (NAC) and S-acetylcysteamine (also known as S-acetyl-{beta}-mercaptoethylamine; SMEA), effectively restored colistin susceptibility against P. aeruginosa by altering biofilm nanomechanical properties. These perturbations in matrix integrity were associated with I-152s ability to hinder the phenazine redox cycle, shifting PYO to a reduced state as well as enabling S-conjugate formation. The compound decreased PYO accumulation in bacterial cultures and PYO-generated reactive oxygen species (ROS) in macrophage cells. Together with PYO, LPS is another driver of ROS-dependent inflammatory signaling in the host, which leads to an uncontrolled cytokine response and organ damage, especially in patients with cystic fibrosis. I-152 treatment downregulated the expression of LPS-induced inflammatory cytokines, i.e., IL-6 and TNF-, in bone marrow-derived macrophages (BMDM) isolated from transgenic CFTR-/- and CFTR+/+ mice. Consistently, I-152 partially counteracted the inflammatory response in the P. aeruginosa LPS-induced acute lung injury murine model. Taken together, these results support I-152 as an adjunctive treatment for P. aeruginosa respiratory infections through a dual mechanism: combating antimicrobial resistance in biofilms and dampening host inflammation in the respiratory system. HighlightsO_LII-152 potentiates colistin activity against P. aeruginosa by compromising the biofilm surface C_LIO_LII-152 rewires the pyocyanin (PYO) redox state and forms covalent adducts with it C_LIO_LIPYO accumulation and PYO-induced ROS generation in macrophages is impaired by I-152 C_LIO_LIEx vivo, I-152 dampens excessive pro-inflammatory response to P. aeruginosa LPS in CFTR-/- and CFTR+/+ BM-derived macrophages C_LIO_LII-152 (140 mg/Kg) attenuates LPS-driven inflammation and lung damage in CFTR+/+ mice C_LI

pharmacology and toxicology↗

bioRxiv2025

Towards an armed oncolytic virus approach to glioblastoma treatment.

Glioblastoma (GBM) is among the most aggressive and lethal human tumors. The current standard of care--surgical resection followed by chemotherapy--offers limited efficacy, as recurrence remains frequent and severe, underscoring the urgent need for novel therapeutic strategies. Photodynamic therapy (PDT) and oncolytic virotherapy have emerged as promising alternatives. PDT utilizes light-sensitive molecules to generate reactive oxygen species (ROS), selectively inducing tumor cell death, while oncolytic virotherapy employs viruses to lyse tumor cells and activate anti-tumor immune responses. Notably, Talimogene laherparepvec (T-VEC), an HSV-1-based oncolytic virus (oHSV1), is already approved for treating unresectable melanoma. To explore a combinatorial approach for GBM, we engineered highly neuroattenuated oHSV1 variants with a genetic background similar to T-VEC, expressing KillerRed (KR)--a photosensitizing protein--alone or in combination with immunotherapeutic factors. Our results demonstrate potent cytolytic effects of these recombinant viruses in multiple murine and human GBM cell lines, as well as in primary tumor cells. In a syngeneic C57BL/6J mouse model, oHSV1 administration alone or carried by monocytes induced extensive tumor necrosis, accompanied by infiltration of CD3+ immune cells.

cancer biology↗