Novichoks are highly toxic chemical warfare agents (CWAs), which gained significant attention after being used in the assassination attempt of Sergei Skripal (2018, Salisbury). Since then, only a limited number of experimental studies on Novichoks were conducted with focus on their physicochemical properties, toxicology and pharmacology. Their stability on various matrices has received even minor consideration. Herein, we present a comprehensive study on the fate of A232, a prominent Novichok agent, on a variety of previously unexamined environmental and urban matrices, using solid and solution state ³¹P NMR techniques. The matrices studied included limestone soil, desert soil, silicate sand, asphalt, fresh and old concrete and sawdust, all in dry and wet forms. A232 was found to be highly persistent on most matrices, with degradation being very slow or nonexistent. Once degradation occurred, its products stemmed from either a PN bond or a PF bond cleavage or double hydrolysis of both leaving groups, depending on the matrix. The results indicate that A232 poses significant, long-term threat to the environment across a diverse range of realistic scenarios. Importantly, A232 adsorbed on solid support was rapidly and completely hydrolyzed to a nontoxic product once treated with only a few equivalents of NaOH.

Background

Neutrophils are critical first responders of the innate immune system, rapidly recruited to sites of infection or sterile injury. Upon activation by pathogen- or damage-associated molecular patterns, neutrophils initiate antimicrobial responses, including cytokine release, phagocytosis, and the formation of neutrophil extracellular traps (NETs). While NETosis plays a protective role, excessive NET formation can exacerbate inflammation and tissue damage. Pulmonary exposure to ricin, a potent toxin derived from Ricinus communis, results in acute lung injury characterized by neutrophil infiltration, cytokine production, vascular leakage, and pulmonary edema. This study investigated the contribution of NETosis to ricin-induced lung pathology and explored the therapeutic potential of targeting NETosis with a long acting recombinant DNase I (PRX-119) to attenuate lung injury.

Methods

CD1 outbreed mice were pulmonary exposed to ricin, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected at various time points post-exposure. NETosis was assessed by immunofluorescence and Western blot analysis of markers, including peptidyl arginine deiminase 4 (PAD4), citrullinated histone H3 (citH3) and myeloperoxidase (MPO). Therapeutic intervention included administration of a NET-degrading DNase agent in combination with an anti-ricin antibody. Cell-free DNA levels, NETosis markers, neutrophil infiltration, lung histopathology, vascular permeability and the expression of pro- and anti-inflammatory mediators were evaluated. Weight loss and survival were also monitored and compared between anti-ricin monotherapy and combined anti-ricin and plant-produced human recombinant long acting (LA) DNase I (PRX-119), a novel NET degradation therapy.

Results

Ricin exposure led to elevated pulmonary levels of PAD4, citH3 and MPO, accompanied by extensive NET formation in both BALF and lung tissue. Mice receiving combined therapy with a newly developed DNase I - based agent (PRX-119) and an anti-ricin antibody treatment exhibited significantly improved survival and reduced weight loss compared to antibody monotherapy. The combined treatment not only significantly reduced NETosis markers, but also improved lung histopathology, reduced vascular leakage and pulmonary edema and altered the levels of proteins involved with pro- or anti-inflammatory effects, Dkk-1, CD93 and Periostin.

Conclusions

These findings demonstrate for the first time that NETosis plays a significant pathological role in ricin-induced lung injury. Moreover, they underscore the therapeutic potential of combining advanced NET-degrading agents, specifically PRX-119, an advanced DNAse I under development, with toxin-neutralizing antibodies as a promising strategy to reduce acute lung damage and enhance clinical outcomes.

Targeting therapeutic nanoparticles to the brain poses a challenge due to the restrictive nature of the blood–brain barrier (BBB). Here we report the development of mRNA-loaded lipid nanoparticles (LNPs) functionalized with BBB-interacting small molecules, thereby enhancing brain delivery and gene expression. Screening brain-targeted mRNA-LNPs in central nervous system (CNS) in vitro models and through intravenous administration in mice demonstrated that acetylcholine-conjugated LNPs achieved superior brain tropism and gene expression, outperforming LNP modifications with nicotine, glucose, memantine, cocaine, tryptophan, and other small molecules. An artificial intelligence (AI)-based model designed to predict the BBB permeability of small-molecule ligands showed strong alignment with our experimental results, providing in vivo validation of its predictive capacity. Cell-specific biodistribution analysis in Cre-reporter Ai9 mice showed that acetylcholine-functionalized LNPs preferentially transfected neurons and astrocytes following either intravenous or intracerebral administration. Mechanistic studies suggest that acetylcholine-LNP uptake is mediated by the functional engagement of acetylcholine receptors (AchRs) followed by endocytosis, which synergistically enhances intracellular mRNA delivery. Moreover, acetylcholine-LNPs successfully crossed a human BBB-on-a-chip model, enabling transgene expression in human iPSC-derived neurons. Their effective penetration and transfection in human brain organoids further support their potential activity in human-based systems. These findings establish a predictive and modular framework for engineering CNS-targeted LNPs, advancing precision gene delivery for brain disorders.

The global escalation of antimicrobial resistance (AMR) among Gram-negative bacteria poses a severe threat to public health. Traditional antibiotic development struggles to keep pace with emerging resistant strains, necessitating innovative strategies to enhance therapeutic options. This review explores the potential of drug repurposing as a strategic approach to combat Gram-negative bacterial infections, focusing on clinically approved drugs with antibacterial properties or the capacity to enhance antibiotic efficacy through direct or host-directed mechanisms. Within the review, a special section is dedicated to the potential usage of repurposed drugs against bacteria that can be used as biological warfare agents, exposure to which may lead to mass casualties, in particular if these pathogens are resistant to antibiotics. Repurposed drugs exhibit diverse antibacterial mechanisms, including membrane disruption, efflux pump inhibition, iron metabolism interference, quorum sensing suppression, and biofilm inhibition. Additionally, many agents demonstrated host-directed therapeutic effects by modulating inflammatory responses, enhancing autophagy, or boosting innate immune functions. Drug repurposing offers a promising avenue to mitigate the AMR crisis by providing rapid, cost-effective therapeutic solutions. Combining repurposed drugs with existing antibiotics or employing them as host-directed therapies holds significant potential for treating infections caused by multidrug-resistant Gram-negative pathogens. Continued research and clinical validation are essential to translate these findings into effective treatment regimens.

Increasing the molecular rigidity of bioactive compounds by intramolecular hydrogen bonds (IMHB) may affect both pharmacodynamics (PD) and pharmacokinetics (PK) by an increase in molecular recognition, lipophilicity and membrane permeability. Recently, in our study on opioids lipophilicity, we suggested two types of IMHBs, i.e., O–H⋯N and N⁺-H^…O, which may exist in 14-oxymorphinan structures and may explain some trends and even apparent anomalies in their pharmacologically relevant molecular properties. In the present study we show, both experimentally and computationally, that these IMHBs indeed exist in the three FDA-approved opioid antagonists, Naloxone, Naltrexone and Nalmefene, as well as in their 3-O- and 14-O-methylated derivatives. Since the charged form of these morphinans is the biologically active species, we propose that the charge-assisted IMHB (CAHB) N⁺-H^…O, which is herein studied for the first time, plays an important role in the bioactivity of this subfamily of opioids.

The present study describes the ability of different water soluble pillararenes (PAs) to complex and solubilize Idebenone (IDE), as a model drug, and the results are compared to previously reported complexes of IDE with cyclodextrins (CDs). We show that P[5]As strongly bind IDE, with the CDs showing lower binding and P[6]As exhibiting the weakest binding. The differences between the weak and strong complexes reached above two orders of magnitude in the binding constants. The solubility-permeability interplay was then investigated to determine the best structures for potential improvement of bioavailability under different circumstances. For unsaturated solutions, using an in-vitro BBB permeability model, the highest permeability was obtained with the weakest complexes, demonstrating the solubility-permeability interplay whereby higher binding leads to lower permeability. However, when saturated solutions/suspensions were used, with the oral in-vitro permeapad® permeability model, stronger complexes led to higher permeabilities and drug flux. By comparing to cyclodextrins we show that PAs may be a significant addition to the CDs family, commonly used for bioavailability improvement in pharmaceutical applications.

Background

In many species, including human, stress is accompanied by disruption of reproductive functions. The endocrine stress-response is activated and regulated by members of the corticotropin releasing factor (CRF) protein family. Stress stimuli may affect reproductive functions locally, recruiting autocrine/paracrine strategies. Yet, the molecular mechanisms mediating these effects are not fully understood.

Methods

To explore the molecular mechanism mediating the ovarian stress response, we used three different models: (1) ICR mice subjected to chronic variable stress (CVS) procedure for 4 weeks. The stress procedure consisted of 9 different stressors per week, approximately 2 stressors per day both in the dark and the light phases. (2) wild-type mice undergoing intraovarian injection of the CRF receptor antagonist, β-asstressin, and (3) CRF-R1 knockout mice.

Results

We report herein that ovulation rate was significantly elevated, and the litter size was substantially increased, in the following estrous cycle of female mice subjected to mild chronic variable stress (CVS). These females exhibited lower serum estrogen levels associated with reduced ovarian 17β-HSD3 expression. Exploration of the involvement of a neuroregulatory mechanism in this event revealed upregulation of the corticotropin releasing factor type 1 receptor (CRFR1) in the theca-interstitial cells of large ovarian follicles. In agreement, CRFR1 knockout mice, as well as wild-type females undergoing intraovarian injection of the CRF receptor antagonist, β-asstressin, displayed reduced ovulation rate, enhanced estrogen secretion and an increase in 17β-HSD3 expression.

Conclusions

Our findings show a direct gonadal response to neuroendocrine and central stress-response regulators. The mechanism of this unexpected beneficial effect of CVS on reproduction may provide a neuro-endocrine background to the well-known “Baby Boom” phenomenon.

Fluorinated diketones (FDKs) are electrophilic moieties holding unique molecular properties that make them potential reversible and multifaceted covalent warheads for drug design. To further explore this potential, the multicomponent equilibrium systems of various fluorinated monoketones (FMKs) and FDKs in the presence of the relevant nucleophilic amino acids serine, cysteine, and lysine are studied. These equilibrium systems are investigated using ¹⁹ F- and ¹³C- NMR spectroscopy, and reveal that for both cysteine and lysine most of the FMKs and FDKs studied may potentially serve as electrophilic warheads for reversible covalent drugs.

The global surge in antimicrobial resistance presents a critical threat to public health, emphasizing the urgent need for the development of new and more effective bacterial vaccines. Since the success of mRNA vaccines during the COVID-19 pandemic, this vaccine strategy has rapidly advanced, with most efforts focused on cancer immunotherapy and targeting viral pathogens. Recently, mRNA vaccines have entered the early phases of clinical development for bacterial diseases. However, bacteria present greater biological complexity compared with viruses, posing additional challenges for vaccine design, such as antigen selection, immune response and mRNA construct design. Here, we discuss critical aspects in the development of bacterial mRNA vaccines, from antigen selection to construct design. We also highlight the current preclinical landscape and discuss remaining translational challenges and future potential for mRNA vaccines against bacterial infections.

Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, exert their potent neuroparalytic effects by specifically targeting presynaptic cholinergic nerve terminals. BoNTs consist of a heavy chain that mediates high-affinity neuronal binding and endocytosis, and a light chain that, once translocated into the cytosol, acts as a zinc-dependent metalloprotease. The light chain cleaves SNARE proteins essential for synaptic vesicle fusion, thereby inhibiting acetylcholine release and leading to flaccid paralysis. This intoxication spans foodborne, wound, and infant botulism, all characterized by commonly observed heat-resistant endospores that enable bacterial survival under adverse conditions. BoNT intoxication induces flaccid paralysis, and both natural and synthetic neurotoxins disrupt neuronal communication by targeting synaptic components. However, BoNTs differ in their origin, mechanism of action, structure, and interactions. Clinical harnessing of non-poisoning low doses of BoNT/A and BoNT/B serotypes is used for alleviating symptoms of diverse diseases. Molecular engineering and clinical formulation enabled BoNTs optimization into pharmacologically safe and targeted therapeutic agents that replicate the selective neuronal silencing observed in their natural forms.