Horizontal mitochondrial transfer as a novel bioenergetic tool for mesenchymal stromal/stem cells: molecular mechanisms and therapeutic potential in a variety of diseases.

Intercellular mitochondrial transfer (MT) is a newly discovered form of cell-to-cell signalling involving the active incorporation of healthy mitochondria into stressed/injured recipient cells, contributing to the restoration of bioenergetic profile and cell viability, reduction of inflammatory processes and normalisation of calcium dynamics. Recent evidence has shown that MT can occur through multiple cellular structures and mechanisms: tunneling nanotubes (TNTs), via gap junctions (GJs), mediated by extracellular vesicles (EVs) and other mechanisms (cell fusion, mitochondrial extrusion and migrasome-mediated mitocytosis) and in different contexts, such as under physiological (tissue homeostasis and stemness maintenance) and pathological conditions (hypoxia, inflammation and cancer). As Mesenchimal Stromal/ Stem Cells (MSC)-mediated MT has emerged as a critical regulatory and restorative mechanism for cell and tissue regeneration and damage repair in recent years, its potential in stem cell therapy has received increasing attention. In particular, the potential therapeutic role of MSCs has been reported in several articles, suggesting that MSCs can enhance tissue repair after injury via MT and membrane vesicle release. For these reasons, in this review, we will discuss the different mechanisms of MSCs-mediated MT and therapeutic effects on different diseases such as neuronal, ischaemic, vascular and pulmonary diseases. Therefore, understanding the molecular and cellular mechanisms of MT and demonstrating its efficacy could be an important milestone that lays the foundation for future clinical trials.

Cytotoxicity, Mitochondrial Functionality, and Redox Status of Human Conjunctival Cells after Short and Chronic Exposure to Preservative-Free Bimatoprost 0.03% and 0.01%: An In Vitro Comparative Study.

Prostaglandin analogues (PGAs), including bimatoprost (BIM), are generally the first-line therapy for glaucoma due to their greater efficacy, safety, and convenience of use. Commercial solutions of preservative-free BIM (BIM 0.03% and 0.01%) are already available, although their topical application may result in ocular discomfort. This study aimed to evaluate the in vitro effects of preservative-free BIM 0.03% vs. 0.01% in the human conjunctival epithelial (HCE) cell line. Our results showed that long-term exposure to BIM 0.03% ensues a significant decrease in cell proliferation and viability. Furthermore, these events were associated with cell cycle arrest, apoptosis, and alterations of ΔΨm. BIM 0.01% does not exhibit cytotoxicity, and no negative influence on conjunctival cell growth and viability or mitochondrial activity has been observed. Short-time exposure also demonstrates the ability of BIM 0.03% to trigger reactive oxygen species (ROS) production and mitochondrial hyperpolarisation. An in silico drug network interaction was also performed to explore known and predicted interactions of BIM with proteins potentially involved in mitochondrial membrane potential dissipation. Our findings overall strongly reveal better cellular tolerability of BIM 0.01% vs. BIM 0.03% in HCE cells.

Synergistic Activity of Ketoconazole and Miconazole with Prochloraz in Inducing Oxidative Stress, GSH Depletion, Mitochondrial Dysfunction, and Apoptosis in Mouse Sertoli TM4 Cells.

Triazole and imidazole fungicides represent an emerging class of pollutants with endocrine-disrupting properties. Concerning mammalian reproduction, a possible causative role of antifungal compounds in inducing toxicity has been reported, although currently, there is little evidence about potential cooperative toxic effects. Toxicant-induced oxidative stress (OS) may be an important mechanism potentially involved in male reproductive dysfunction. Thus, to clarify the molecular mechanism underlying the effects of azoles on male reproduction, the individual and combined potential of fluconazole (FCZ), prochloraz (PCZ), miconazole (MCZ), and ketoconazole (KCZ) in triggering in vitro toxicity, redox status alterations, and OS in mouse TM4 Sertoli cells (SCs) was investigated. In the present study, we demonstrate that KCZ and MCZ, alone or in synergistic combination with PCZ, strongly impair SC functions, and this event is, at least in part, ascribed to OS. In particular, azoles-induced cytotoxicity is associated with growth inhibitory effects, G0/G1 cell cycle arrest, mitochondrial dysfunction, reactive oxygen species (ROS) generation, imbalance of the superoxide dismutase (SOD) specific activity, glutathione (GSH) depletion, and apoptosis. N-acetylcysteine (NAC) inhibits ROS accumulation and rescues SCs from azole-induced apoptosis. PCZ alone exhibits only cytostatic and pro-oxidant properties, while FCZ, either individually or in combination, shows no cytotoxic effects up to 320 µM.

Bisphenol A Deranges the Endocannabinoid System of Primary Sertoli Cells with an Impact on Inhibin B Production.

Bisphenol A (BPA) is an endocrine disruptor that negatively affects spermatogenesis, a process where Sertoli cells play a central role. Thus, in the present study we sought to ascertain whether BPA could modulate the endocannabinoid (eCB) system in exposed mouse primary Sertoli cells. Under our experimental conditions, BPA turned out to be cytotoxic to Sertoli cells with an half-maximal inhibitory concentration (IC50) of ~6.0 µM. Exposure to a non-cytotoxic dose of BPA (i.e., 0.5 µM for 48 h) increased the expression levels of specific components of the eCB system, namely: type-1 cannabinoid (CB1) receptor and diacylglycerol lipase-α (DAGL-α), at mRNA level, type-2 cannabinoid (CB2) receptor, transient receptor potential vanilloid 1 (TRPV1) receptors, and DAGL-ß, at protein level. Interestingly, BPA also increased the production of inhibin B, but not that of transferrin, and blockade of either CB2 receptor or TRPV1 receptor further enhanced the BPA effect. Altogether, our study provides unprecedented evidence that BPA deranges the eCB system of Sertoli cells towards CB2- and TRPV1-dependent signal transduction, both receptors being engaged in modulating BPA effects on inhibin B production. These findings add CB2 and TRPV1 receptors, and hence the eCB signaling, to the other molecular targets of BPA already known in mammalian cells.

Effects of reduced natural background radiation on Drosophila melanogaster growth and development as revealed by the FLYINGLOW program.

Natural background radiation of Earth and cosmic rays played a relevant role during the evolution of living organisms. However, how chronic low doses of radiation can affect biological processes is still unclear. Previous data have indicated that cells grown at the Gran Sasso Underground Laboratory (LNGS, L'Aquila) of National Institute of Nuclear Physics (INFN) of Italy, where the dose rate of cosmic rays and neutrons is significantly reduced with respect to the external environment, elicited an impaired response against endogenous damage as compared to cells grown outside LNGS. This suggests that environmental radiation contributes to the development of defense mechanisms at cellular level. To further understand how environmental radiation affects metabolism of living organisms, we have recently launched the FLYINGLOW program that aims at exploiting Drosophila melanogaster as a model for evaluating the effects of low doses/dose rates of radiation at the organismal level. Here, we will present a comparative data set on lifespan, motility and fertility from different Drosophila strains grown in parallel at LNGS and in a reference laboratory at the University of L'Aquila. Our data suggest the reduced radiation environment can influence Drosophila development and, depending on the genetic background, may affect viability for several generations even when flies are moved back to normal background radiation. As flies are considered a valuable model for human biology, our results might shed some light on understanding the effect of low dose radiation also in humans.

Apoptotic effects of bovine apo-lactoferrin on HeLa tumor cells.

Lactoferrin (Lf), a cationic iron-binding glycoprotein of 80 kDa present in body secretions, is known as a compound with marked antimicrobial activity. In the present study, the apoptotic effect of iron-free bovine lactoferrin (apo-bLf) on human epithelial cancer (HeLa) cells was examined in association with reactive oxygen species and glutathione (GSH) levels. Apoptotic effect of iron-free bovine lactoferrin inhibited the growth of HeLa cells after 48 hours of treatment while the diferric-bLf was ineffective in the concentration range tested (from 1 to 12.5 µM). Western blot analysis showed that key apoptotic regulators including Bax, Bcl-2, Sirt1, Mcl-1, and PARP-1 were modulated by 1.25 µM of apo-bLf. In the same cell line, apo-bLf induced apoptosis together with poly (ADP-ribose) polymerase cleavage, caspase activation, and a significant drop of NAD+ . In addition, apo-bLf-treated HeLa cells showed a marked increase of reactive oxygen species level and a significant GSH depletion. On the whole, apo-bLf triggered apoptosis of HeLa cells upon oxygen radicals burst and GSH decrease.

ELF-MF attenuates quercetin-induced apoptosis in K562 cells through modulating the expression of Bcl-2 family proteins.

This study investigated the effects of sinusoidal ELF-MF (1 mT; 50 Hz) on the apoptosis induced by four different compounds, namely vinblastine, etoposide, quercetin, and resveratrol, in human K562 chronic myeloid leukemia cells. The exposure to ELF-MF did not affect growth and viability of untreated K562 cells and did not influence the anti-proliferative effects of resveratrol, vinblastine, and etoposide. On the contrary, in quercetin-treated cells, exposure to ELF-MF significantly reduced the percentage of apoptotic cells and the caspase-3 activity and modified the cell cycle profile especially after 48 h of exposure. In addition, the simultaneous treatments for 24 h with quercetin plus ELF-MF increased Bcl-2 protein expression and prevented quercetin-induced downregulation of Mcl-1 and Bcl-xL. Finally, an increase of HSP70 expression was also observed after prolonged ELF-MF treatment. The ELF-MF-dependent modulation of the expression of anti-apoptotic Bcl-2 family and Hsp70 proteins could act as a pro-survival mechanism in K562 cells.

Mitochondrial Extracellular Vesicles (mitoEVs): Emerging mediators of cell-to-cell communication in health, aging and age-related diseases.

Mitochondria are metabolic and signalling hubs that integrate a plethora of interconnected processes to maintain cell homeostasis. They are also dormant mediators of inflammation and cell death, and with aging damages affecting mitochondria gradually accumulate, resulting in the manifestation of age-associated disorders. In addition to coordinate multiple intracellular functions, mitochondria mediate intercellular and inter-organ cross talk in different physiological and stress conditions. To fulfil this task, mitochondrial signalling has evolved distinct and complex conventional and unconventional routes of horizontal/vertical mitochondrial transfer. In this regard, great interest has been focused on the ability of extracellular vesicles (EVs), such as exosomes and microvesicles, to carry selected mitochondrial cargoes to target cells, in response to internal and external cues. Over the past years, the field of mitochondrial EVs (mitoEVs) has grown exponentially, revealing unexpected heterogeneity of these structures associated with an ever-expanding mitochondrial function, though the full extent of the underlying mechanisms is far from being elucidated. Therefore, emerging subsets of EVs encompass exophers, migrasomes, mitophers, mitovesicles, and mitolysosomes that can act locally or over long-distances to restore mitochondrial homeostasis and cell functionality, or to amplify disease. This review provides a comprehensive overview of our current understanding of the biology and trafficking of MitoEVs in different physiological and pathological conditions. Additionally, a specific focus on the role of mitoEVs in aging and the onset and progression of different age-related diseases is discussed.

Mechanism of non-competitive inhibition of the SARS-CoV-2 3CL protease dimerization: Therapeutic and clinical promise of the lichen secondary metabolite perlatolinic acid.

In response to the COVID-19 pandemic, identifying effective treatments against SARS-CoV-2 has become of utmost importance. This study elucidates the mechanism by which perlatolinic acid, a lichen-derived secondary metabolite, non-competitively inhibits the dimerization of the SARS-CoV-2 3CL protease, a pivotal enzyme in the virus lifecycle. Utilising a combination of kinetic parameter determination, inhibition assays, and molecular docking studies, we demonstrate that perlatolinic acid effectively disrupts the enzymatic function by binding at the dimer interface with a measured K i value of 0.67 µM, thereby impeding the protease catalytic activity essential for viral replication. Molecular docking studies further corroborate the binding specificity of perlatolinic acid to the dimer interface, which is attributed to the loss of key interactions essential for dimerization, consequently impairing catalytic activity, highlighting its potential as a scaffold for developing broad-spectrum antiviral drugs. Despite a dose-dependent cytotoxicity of perlatolinic acid, its TC 50 is approximately 43 times higher than the K i value. Our findings suggest that perlatolinic acid holds significant promise as a lead compound for the development of new therapeutics against COVID-19, warranting further investigation and clinical evaluation. In conclusion, the study sheds light on the therapeutic potential of natural compounds in combating SARS-CoV-2, paving the way for the exploration of lichen secondary metabolites as a reservoir of potential antiviral agents.

Oxidative Stress, Cytotoxic and Inflammatory Effects of Azoles Combinatorial Mixtures in Sertoli TM4 Cells.

Triazole and imidazole fungicides are an emerging class of contaminants with an increasing and ubiquitous presence in the environment. In mammals, their reproductive toxicity has been reported. Concerning male reproduction, a combinatorial activity of tebuconazole (TEB; triazole fungicide) and econazole (ECO; imidazole compound) in inducing mitochondrial impairment, energy depletion, cell cycle arrest, and the sequential activation of autophagy and apoptosis in Sertoli TM4 cells (SCs) has recently been demonstrated. Given the strict relationship between mitochondrial activity and reactive oxygen species (ROS), and the causative role of oxidative stress (OS) in male reproductive dysfunction, the individual and combined potential of TEB and ECO in inducing redox status alterations and OS was investigated. Furthermore, considering the impact of cyclooxygenase (COX)-2 and tumor necrosis factor-alpha (TNF-α) in modulating male fertility, protein expression levels were assessed. In the present study, we demonstrate that azoles-induced cytotoxicity is associated with a significant increase in ROS production, a drastic reduction in superoxide dismutase (SOD) and GSH-S-transferase activity levels, and a marked increase in the levels of oxidized (GSSG) glutathione. Exposure to azoles also induced COX-2 expression and increased TNF-α production. Furthermore, pre-treatment with N-acetylcysteine (NAC) mitigates ROS accumulation, attenuates COX-2 expression and TNF-α production, and rescues SCs from azole-induced apoptosis, suggesting a ROS-dependent molecular mechanism underlying the azole-induced cytotoxicity.

Multi-Target Effects of ß-Caryophyllene and Carnosic Acid at the Crossroads of Mitochondrial Dysfunction and Neurodegeneration: From Oxidative Stress to Microglia-Mediated Neuroinflammation.

Inflammation and oxidative stress are interlinked and interdependent processes involved in many chronic diseases, including neurodegeneration, diabetes, cardiovascular diseases, and cancer. Therefore, targeting inflammatory pathways may represent a potential therapeutic strategy. Emerging evidence indicates that many phytochemicals extracted from edible plants have the potential to ameliorate the disease phenotypes. In this scenario, ß-caryophyllene (BCP), a bicyclic sesquiterpene, and carnosic acid (CA), an ortho-diphenolic diterpene, were demonstrated to exhibit anti-inflammatory, and antioxidant activities, as well as neuroprotective and mitoprotective effects in different in vitro and in vivo models. BCP essentially promotes its effects by acting as a selective agonist and allosteric modulator of cannabinoid type-2 receptor (CB2R). CA is a pro-electrophilic compound that, in response to oxidation, is converted to its electrophilic form. This can interact and activate the Keap1/Nrf2/ARE transcription pathway, triggering the synthesis of endogenous antioxidant "phase 2" enzymes. However, given the nature of its chemical structure, CA also exhibits direct antioxidant effects. BCP and CA can readily cross the BBB and accumulate in brain regions, giving rise to neuroprotective effects by preventing mitochondrial dysfunction and inhibiting activated microglia, substantially through the activation of pro-survival signalling pathways, including regulation of apoptosis and autophagy, and molecular mechanisms related to mitochondrial quality control. Findings from different in vitro/in vivo experimental models of Parkinson's disease and Alzheimer's disease reported the beneficial effects of both compounds, suggesting that their use in treatments may be a promising strategy in the management of neurodegenerative diseases aimed at maintaining mitochondrial homeostasis and ameliorating glia-mediated neuroinflammation.

Mitochondrial and metabolic alterations in cancer cells.

Metabolic alterations have been observed in many cancer types. The deregulated metabolism has thus become an emerging hallmark of the disease, where the metabolism is frequently rewired to aerobic glycolysis. This has led to the concept of "metabolic reprogramming", which has therefore been extensively studied. Over the years, it has been characterized the enhancement of aerobic glycolysis, where key mutations in some of the enzymes of the TCA cycle, and the increased glucose uptake, are used by cancer cells to achieve a "metabolic phenotype" useful to gain a proliferation advantage. Many studies have highlighted in detail the signaling pathways and the molecular mechanisms responsible for the glycolytic switch. However, glycolysis is not the only metabolic process that cancer cells rely on. Oxidative Phosphorylation (OXPHOS), gluconeogenesis or the beta-oxidation of fatty acids (FAO) may be involved in the development and progression of several tumors. In some cases, these metabolisms are even more crucial than aerobic glycolysis for the tumor survival. This review will focus on the contribution of these alterations of metabolism to the development and survival of cancers. We will also analyze the molecular mechanisms by which the balance between these metabolic processes may be regulated, as well as some of the therapeutical approaches that can derive from their study.

Protocetraric and Salazinic Acids as Potential Inhibitors of SARS-CoV-2 3CL Protease: Biochemical, Cytotoxic, and Computational Characterization of Depsidones as Slow-Binding Inactivators.

The study investigated the inhibitory activity of protocetraric and salazinic acids against SARS-CoV-2 3CLpro. The kinetic parameters were determined by microtiter plate-reading fluorimeter using a fluorogenic substrate. The cytotoxic activity was tested on murine Sertoli TM4 cells. In silico analysis was performed to ascertain the nature of the binding with the 3CLpro. The compounds are slow-binding inactivators of 3CLpro with a Ki of 3.95 µM and 3.77 µM for protocetraric and salazinic acid, respectively, and inhibitory efficiency kinact/Ki at about 3 × 10-5 s-1µM-1. The mechanism of inhibition shows that both compounds act as competitive inhibitors with the formation of a stable covalent adduct. The viability assay on epithelial cells revealed that none of them shows cytotoxicity up to 80 µM, which is well below the Ki values. By molecular modelling, we predicted that the catalytic Cys145 makes a nucleophilic attack on the carbonyl carbon of the cyclic ester common to both inhibitors, forming a stably acyl-enzyme complex. The computational and kinetic analyses confirm the formation of a stable acyl-enzyme complex with 3CLpro. The results obtained enrich the knowledge of the already numerous biological activities exhibited by lichen secondary metabolites, paving the way for developing promising scaffolds for the design of cysteine enzyme inhibitors.

The Botanical Drug PBI-05204, a Supercritical CO2 Extract of Nerium Oleander, Is Synergistic With Radiotherapy in Models of Human Glioblastoma.

Glioblastoma multiforme (GBM) is the most common as well as one of the most malignant types of brain cancer. Despite progress in development of novel therapies for the treatment of GBM, it remains largely incurable with a poor prognosis and a very low life expectancy. Recent studies have shown that oleandrin, a unique cardiac glycoside from Nerium oleander, as well as a defined extract (PBI-05204) that contains this molecule, inhibit growth of human glioblastoma, and modulate glioblastoma patient-derived stem cell-renewal properties. Here we demonstrate that PBI-05204 treatment leads to an increase in vitro in the sensitivity of GBM cells to radiation in which the main mechanisms are the transition from autophagy to apoptosis, enhanced DNA damage and reduced DNA repair after radiotherapy (RT) administration. The combination of PBI-05204 with RT was associated with reduced tumor progression evidenced by both subcutaneous as well as orthotopic implanted GBM tumors. Collectively, these results reveal that PBI-05204 enhances antitumor activity of RT in preclinical/murine models of human GBM. Given the fact that PBI-05204 has already been examined in Phase I and II clinical trials for cancer patients, its efficacy when combined with standard-of-care radiotherapy regimens in GBM should be explored.

Involvement of mitochondrial activity in mediating ELF-EMF stimulatory effect on human sperm motility.

It has recently been reported that the exposure of human spermatozoa to an extremely low frequency (ELF) electromagnetic field (EMF) with a square waveform of 5 mT amplitude and frequency of 50 Hz improves sperm motility. The functional relationship between the energy metabolism and the enhancement of human sperm motility induced by ELF-EMF was investigated. Sperm exposure to ELF-EMF resulted in a progressive and significant increase of mitochondrial membrane potential and levels of ATP, ADP and NAD(+) that was associated with a progressive and significant increase in the sperm kinematic parameters. No significant effects were detected on other parameters such as ATP/ADP ratio and energy charge. When carbamoyl cyanide m-chlorophenylhydrazone (CICCP) was applied to inhibit the oxidative phosphorylation in the mitochondria, the values of energy parameters and motility in the sperm incubated in the presence of glucose and exposed to ELF-EMF did not change, thus indicating that the glycolysis was not involved in mediating ELF-EMF stimulatory effect on motility. By contrast, when pyruvate and lactate were provided instead of glucose, the energy status and motility increased significantly in ELF-EMF-treated sperm. Under these culture conditions, the inhibition of glycolitic metabolism by 2-deoxy-D-glucose (DOG) again resulted in increased values of energy and kinematic parameters, indicating that gluconeogenesis was not involved in producing glucose for use in glycolysis. We concluded that the key role in mediating the stimulatory effects exerted by ELF-EMF on human sperm motility is played by mitochondrial oxidative phosphorylation rather than glycolysis.

Mitophagy: Molecular Mechanisms, New Concepts on Parkin Activation and the Emerging Role of AMPK/ULK1 Axis.

Mitochondria are multifunctional subcellular organelles essential for cellular energy homeostasis and apoptotic cell death. It is, therefore, crucial to maintain mitochondrial fitness. Mitophagy, the selective removal of dysfunctional mitochondria by autophagy, is critical for regulating mitochondrial quality control in many physiological processes, including cell development and differentiation. On the other hand, both impaired and excessive mitophagy are involved in the pathogenesis of different ageing-associated diseases such as neurodegeneration, cancer, myocardial injury, liver disease, sarcopenia and diabetes. The best-characterized mitophagy pathway is the PTEN-induced putative kinase 1 (PINK1)/Parkin-dependent pathway. However, other Parkin-independent pathways are also reported to mediate the tethering of mitochondria to the autophagy apparatuses, directly activating mitophagy (mitophagy receptors and other E3 ligases). In addition, the existence of molecular mechanisms other than PINK1-mediated phosphorylation for Parkin activation was proposed. The adenosine5'-monophosphate (AMP)-activated protein kinase (AMPK) is emerging as a key player in mitochondrial metabolism and mitophagy. Beyond its involvement in mitochondrial fission and autophagosomal engulfment, its interplay with the PINK1-Parkin pathway is also reported. Here, we review the recent advances in elucidating the canonical molecular mechanisms and signaling pathways that regulate mitophagy, focusing on the early role and spatial specificity of the AMPK/ULK1 axis.

Lactobacillus sakei Pro-Bio65 Reduces TNF-α Expression and Upregulates GSH Content and Antioxidant Enzymatic Activities in Human Conjunctival Cells.

Purpose: The study investigates the regulatory effects exhibited by lysate of Lactobacillus sakei pro-Bio65 (4%; L.SK) on the human conjunctival epithelial (HCE) cell line. Methods: Trypan blue and methylthiazol tetrazolium (MTT) methods were used to assess cell growth and viability. Mitochondrial membrane potential was assessed by JC-1 staining and cytofluorimetric detection methods. The antioxidant pattern and the intracellular reactive oxygen species (ROS) levels were analyzed by spectrophotometric and spectrofluorimetric methods. NF-κB luciferase activity was quantified by luminometric detection. NF-κB nuclear translocation, as well as mitochondrial morphology, were investigated by immunofluorescence using confocal microscopy. Cytokines and COX2 expression levels were determined by Western blot analyses. Results: This study demonstrates that L.SK exposure does not influence HCE cell proliferation and viability in vitro. L.SK paraprobiotic induces mild-low levels of intracellular ROS. It is coupled to changes in the mitochondrial membrane potential (ΔΨm), in a context of a regular mitochondrial-network organization. The negative modulation of tumor necrosis factor alpha (TNF-α) expression levels and rising antioxidant defense efficiency, mediated by the upregulation of glutathione (GSH) and increased antioxidant enzymatic activities, were observed. Conclusions: This study demonstrates that L.SK empowers the antioxidant endogenous efficiency of HCE cells, by the upregulation of the GSH content and the enzymatic antioxidant pattern, and concurrently reduces TNF-α protein expression. Translational Relevance: Although the obtained in vitro results should be confirmed by in vivo investigations, our data suggest the possibility of L.SK paraprobiotic application for promoting eye health, exploring its use as an endogen antioxidant system inducer in preventing and treating different oxidative stress-based, inflammatory, and age-related conditions.

Cyclic and Acyclic Amine Oxide Alkyl Derivatives as Potential Adjuvants in Antimicrobial Chemotherapy against Methicillin-Resistant Staphylococcus aureus with an MDR Profile.

The dramatic intensification of antimicrobial resistance occurrence in pathogenic bacteria concerns the global community. The revitalisation of inactive antibiotics is, at present, the only way to go through this health system crisis and the use of antimicrobial adjuvants is turning out the most promising approach. Due to their low toxicity, eco-friendly characteristics and antimicrobial activity, amphoteric surfactants are good candidates. This study investigated the adjuvant potentialities of commercial acyclic and newly cyclic N-oxide surfactants combined with therapeutically available antibiotics against MDR methicillin-resistant Staphylococcus aureus (MRSA). The safety profile of the new cyclic compounds, compared to commercial surfactants, was preliminarily assessed, evaluating the cytotoxicity on human peripheral mononuclear blood cells and the haemolysis in human red blood cells. The compounds show an efficacious antimicrobial activity strongly related to the length of the carbon atom chain. In drug-drug interaction assays, all surfactants act synergistically, restoring sensitivity to oxacillin in MRSA, with dodecyl acyclic and cyclic derivatives being the most effective. After evaluating the cytotoxicity and considering the antimicrobial action, the most promising compound is the L-prolinol amine-oxide C12NOX. These findings suggest that the combination of antibiotics with amphoteric surfactants is a valuable therapeutic option for topical infections sustained by multidrug-resistant S. aureus.

Antimycotic Activity of Ozonized Oil in Liposome Eye Drops against Candida spp.

Purpose: This study aims to investigate the antifungal activity and mechanism of action of ozonized oil eye drops in liposomes (Ozodrop), commercialized as eye lubricant for the treatment of dry eye syndrome and eye inflammation. The activity was tested against four clinical Candida species: Calbicans,Cglabrata,Ckrusei, and Corthopsilosis. Methods: The antifungal activity of the eye drop solution was ascertained by microdilution method in accordance with EUCAST obtaining the minimum inhibitory concentration for Ozodrop. The mechanism of action was further investigated in Calbicans by measuring cell vitality, intracellular reactive oxygen species production, levels of cellular and mitochondrial (∆Ψm) membrane potential, and the extent of membrane lipid peroxidation. Results: All Candida isolates were susceptible to Ozodrop with minimum inhibitory concentration values ranging from 0.195% (v/v) for Cglabrata to 6.25% (v/v) for Corthopsilosis. After 1 hour of exposure at the minimum inhibitory concentration value about 30% of cells were killed, reaching about 70% at the highest Ozodrop value. After Ozodrop exposure, Calbicans showed cell membrane depolarization, increased levels of lipid peroxidation, depolarized ∆Ψm, and increased reactive oxygen species generation. Conclusions: The significant increases in reactive oxygen species production cause the accumulation of reactive oxygen species-associated damages leading to progressive Candida cell dysfunction. Translational Relevance: The antifungal activity of Ozodrop was demonstrated at concentrations several times lower than the concentration that can be retrieved in ocular surface after its application. The antifungal activity of the eye drops Ozodrop would represent an interesting off-label indication for a product basically conceived as an eye lubricant.