Biology subjects

Iovino, F.

Publications and source records attributed to Iovino, F..

5 recordsLinked to original sources

bioRxiv2026

Bioengineered extracellular vesicles mitigate neuroinflammation by neutralizing pneumolysin and delaying disease onset in experimental pneumococcal meningitis

Bacterial meningitis is a life-threatening neurological disorder frequently caused by a Streptococcus pneumoniae (the pneumococcus) infection of the brain. Standard treatment consists of antibiotics to eliminate bacteria and dexamethasone to reduce inflammation. Despite this, mortality reaches 20% in treated individuals, and half of the survivors suffer long-term neurological sequelae. This is largely due to the poor capacity of antibiotics to reach the brain and the lack of antimicrobial treatment capable of neutralizing the pneumococcal toxin pneumolysin (Ply). To address these limitations, we isolated extracellular vesicles (EVs) derived from human HEK293T cells and evaluated their therapeutic potential in pneumococcal meningitis. Alongside wild-type EVs (WT.EVs), we bioengineered EVs to express RVG peptides (RVG.EV) for targeting neuronal acetylcholine receptors, signal incompetent IL-6 signal transducer (IL-6ST) decoy receptors (IL-6.EV) to block the pro-inflammatory signalling of IL-6, or EVs expressing both RVG peptides and IL-6ST (DB.EV). In vitro, all EVs reduced pneumococcal adhesion to neurons and mitigated cytotoxicity by binding and sequestering Ply. In a bacteremia-derived pneumococcal meningitis model, EV treatment significantly increased the survival of the mice without affecting bacterial load in the brain or the periphery. Among all groups, RVG.EV treatment was most effective in reducing pro-inflammatory cytokine release in the periphery and brain. These findings highlight the therapeutic potential of bioengineered EVs, particularly RVG peptides expressing EVs, as an adjunctive treatment for pneumococcal meningitis thanks to their (i) sequestration and neutralization of Ply, (ii) increased blood-brain barrier crossing, and (iii) dampening of inflammation.

neuroscience↗

bioRxiv2025

Bacteriophage-derived endolysins restore antibiotic susceptibility in penicillin- and erythromycin-resistant Streptococcus pneumoniae infections

Streptococcus pneumoniae, the pneumococcus, is a cause of major illness globally. Invasive pneumococcal disease (IPD) is characterized by pneumococci invading blood (bacteremia), lungs (pneumonia), or brain and cerebrospinal fluid (meningitis). Meningitis remains an important global health concern because half of the survivors experience long-term neurological damage. The antibiotics commonly used to treat pneumococcal infections are {beta}-lactams and macrolides, however, S. pneumoniae is nowadays often resistant to one or several antibiotics, therefore novel antimicrobials are needed. Here, we found that the bacteriophage-derived Cpl-1 endolysin showed consistent antibacterial activity against {beta}-lactam- and macrolide-resistant pneumococcal clinical strains grown in human blood and human cerebrospinal fluid. Exploiting synergistic and additive mechanisms, supplementation of cpl-1 to either penicillin or erythromycin rescued human neuronal cells from the cytotoxicity of antibiotic-resistant pneumococcal infections. Finally, systemic administration of cpl-1 supplemented to penicillin in mice infected with penicillin-resistant pneumococci successfully reduced bacteremia, and, thanks to the efficient penetration across the blood-brain barrier, abolished bacterial load in the brain, resulting in increased (89%) survival accompanied by an asymptomatic course of infection. These findings strongly indicate that cpl-1 can restore antibiotic sensitivity against {beta}-lactam- and macrolide-resistant S. pneumoniae, representing a fundamental adjunct therapy to standard-of-care antibiotics against multidrug-resistant IPD.

microbiology↗

bioRxiv2023

Spatio-temporal brain invasion pattern of Streptococcus pneumoniae and dynamic changes of the cellular environment in meningitis pathogenesis.

Streptococcus pneumoniae (the pneumococcus) is the major cause of bacterial meningitis globally, and pneumococcal meningitis is associated with increased risk of long-term neurological sequelae. These include several sensorimotor functions that are controlled by specific brain regions which, during bacterial meningitis, are damaged by the vast neuroinflammation and bacterial toxins. Little is known about the invasion pattern of the pneumococcus into the brain. Using a bacteremia-derived meningitis mouse model, we combined 3D whole brain imaging with brain microdissection to show that all brain regions were equally affected during disease progression, with pneumococci in close association to the microvasculature. In the hippocampus, the invasion provoked a dynamic microglial response, while the dentate gyrus showed a significant loss of neuroblasts. Our results indicate that, even before symptom occur, the bacterial load throughout the brain causes neuroinflammation and cell death, a pathological scenario which ultimately leads to a failing regeneration of new neurons.

neuroscience↗

bioRxiv2022

Dysfunctional glymphatic system with disrupted aquaporin-4 expression pattern on astrocytes causes bacterial product accumulation in the CSF during pneumococcal meningitis

BackgroundPneumococcal meningitis, inflammation of the meninges due to an infection of the Central Nervous System caused by Streptococcus pneumoniae (the pneumococcus), is the most common form of community-acquired bacterial meningitis globally. The brain is separated from the systemic circulation by the blood-brain barrier (BBB), and meningitis triggers the host immune response increasing the BBB permeability, allowing peripheral immune cells to reach the cerebrospinal fluid (CSF), and increasing debris production. The glymphatic system is a glial-dependent clearance pathway that drives the exchange of compounds between the brain parenchyma and the CSF regulating the waste clearance away from the brain. Aquaporin-4 (AQP4)-water channels on astrocytic end feet regulate the solute transport of the glymphatic system. MethodsWistar rats, either subjected to pneumococcal meningitis or to artificial-CSF (sham), received Evans blue albumin (EBA) intracisternal. Overall, the meningitis group presented a significant impairment of the glymphatic system by retaining the EBA in the brain without consistently releasing the EBA into the bloodstream compared to the sham non-infected group. Through western blot and immunofluorescence microscopy analysis using rat CSF and brain tissue sections, an increased accumulation of pneumococci was detected over time in the CSF, and because of a loss of drainage between CSF and brain interstitial space, such bacterial accumulation was not observed in the brain parenchyma. Western blot analysis for Iba1, TMEM119 and IFN-{gamma} in rat brain homogenates and NSE in serum showed increased neuroinflammation and neuronal damage in the brain over time during pneumococcal infection. Neurological impairment upon neuronal cell damage caused by meningitis with a malfunctioning glymphatic system was also demonstrated through open-field behavioral tests comparing rats from sham and meningitis groups. Lastly, protein expression analysis of AQP4 revealed no differences in AQP4 between the brains of the rats from the meningitis group and those from the sham non-infected rats. Importantly, confocal microscopy analysis showed a detachment of the astrocytic end feet from the BBB vascular endothelium with consequent misplacement of AQP4-water channels. ConclusionsThese findings clearly indicate that pneumococcal meningitis decreases the glymphatic systems functionality, increasing the neurotoxic waste debris in the brain ultimately leading to brain-wide neuroinflammation and neuronal damage. Finally, our results clearly showed that during pneumococcal meningitis, the glymphatic system does not function because of a detachment of the astrocytic end feet from the BBB vascular endothelium, which leads to a misplacement of AQP4 with consequent the loss of the AQP4-water channels functionality.

neuroscience↗

bioRxiv2020

Neuronal death in pneumococcal meningitis is triggered by pneumolysin and pilus-1 interactions with β-actin

Neuronal damage is a major consequence of bacterial meningitis, but little is known about mechanisms that lead to neuronal death. Streptococcus pneumoniae (pneumococcus) is a leading cause of bacterial meningitis and many survivors develop neurological sequelae after the acute infection has resolved, possibly due to neuronal damage. Here, we studied mechanisms for pneumococcal interactions with neurons. Using human primary neurons and co-immunoprecipitation assays, we showed that pneumococci interact with the cytoskeleton protein {beta}-actin through the pilus-1 adhesin RrgA and the cytotoxin pneumolysin (Ply), thereby promoting adhesion and uptake into neurons and neuronal death. Using our bacteremia-derived meningitis mouse model, we observed that RrgA- and Ply-expressing pneumococci co-localize with neuronal {beta}-actin. We found that pneumococcal-infected neurons show increased intracellular Ca2+ levels depending on RrgA and mainly Ply which likely cause actin cytoskeleton disassembly leading to neuronal damage. Finally, neuronal death caused by pneumococcal infection could be inhibited using antibody against {beta}-actin.

microbiology↗