Targeting S. aureus Extracellular Vesicles: A New Putative Strategy to Counteract Their Pathogenic Potential.

Long-term inflammatory skin disease atopic dermatitis is characterized by dry skin, itching, and eczematous lesions. During inflammation skin barrier protein impairment promotes S. aureus colonisation in the inflamed skin, worsening AD patient's clinical condition. Proteomic analysis revealed the presence of several immune evasion proteins and virulence factors in S. aureus extracellular vesicles (EVs), suggesting a possible role for these proteins in the pathophysiology of atopic dermatitis. The objective of this study is to assess the efficacy of a wall fragment obtained from a patented strain of C. acnes DSM28251 (c40) and its combination with a mucopolysaccharide carrier (HAc40) in counteract the pathogenic potential of EVs produced by S. aureus ATCC 14458. Results obtained from in vitro studies on HaCaT keratinocyte cells showed that HAc40 and c40 treatment significantly altered the size and pathogenicity of S. aureus EVs. Specifically, EVs grew larger, potentially reducing their ability to interact with the target cells and decreasing cytotoxicity. Additionally, the overexpression of the tight junctions mRNA zona occludens 1 (ZO1) and claudin 1 (CLDN1) following EVs exposure was decreased by HAc40 and c40 treatment, indicating a protective effect on the epidermal barrier's function. These findings demonstrate how Hac40 and c40 may mitigate the harmful effects of S. aureus EVs. Further investigation is needed to elucidate the exact mechanisms underlying this interaction and explore the potential clinical utility of c40 and its mucopolysaccharide carrier conjugate HAc40 in managing atopic dermatitis.

Ozonated Oil in Liposome Eyedrops Reduces the Formation of Biofilm, Selection of Antibiotic-Resistant Bacteria, and Adhesion of Bacteria to Human Corneal Cells.

The recent attention to the risk of potential permanent eye damage triggered by ocular infections has been leading to a deeper investigation of the current antimicrobials. An antimicrobial agent used in ophthalmology should possess the following characteristics: a broad antimicrobial spectrum, prompt action even in the presence of organic matter, and nontoxicity. The objective of this study is to compare the antimicrobial efficacy of widely used ophthalmic antiseptics containing povidone-iodine, chlorhexidine, and liposomes containing ozonated sunflower oil. We determined the minimum inhibitory concentration (MIC) on various microbial strains: Staphylococcus aureus (ATCC 6538), methicillin-resistant Staphylococcus aureus (ATCC 33591), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aeruginosa (ATCC 9027), and Escherichia coli (ATCC 873). Furthermore, we assessed its efficacy in controlling antibiotic resistance, biofilm formation, and bacterial adhesion. All three antiseptic ophthalmic preparations showed significant anti-microbicidal and anti-biofilm activity, with the liposomes containing ozonated sunflower oil with the highest ability to control antibiotic resistance and bacteria adhesion to human corneal cells.

A Wall Fragment of Cutibacterium acnes Preserves Junctional Integrity Altered by Staphylococcus aureus in an Ex Vivo Porcine Skin Model.

(1) Background alteration of the skin microbiota, dysbiosis, causes skin barrier impairment resulting in disease development. Staphylococcus aureus, the main pathogen associated with dysbiosis, secretes several virulence factors, including α-toxin that damages tight junctions and compromises the integrity of the skin barrier. The use of members of the resident microbiota to restore the skin barrier, bacteriotherapy, represents a safe treatment for skin conditions among innovative options. The aim of this study is the evaluation of a wall fragment derived from a patented strain of Cutibacterium acnes DSM28251 (c40) alone and conjugated to a mucopolysaccharide carrier (HAc40) in counteracting S. aureus pathogenic action on two tight junction proteins (Claudin-1 and ZO-1) in an ex vivo porcine skin infection model. Methods: skin biopsies were infected with live S. aureus strains ATCC29213 and DSM20491. Tissue was pre-incubated or co-incubated with c40 and HAc40. (3) Results: c40 and HAc40 prevent and counteract Claudin-1 and Zo-1 damage (4) Conclusions: c40 and the functional ingredient HAc40 represent a potential non-pharmacological treatment of skin diseases associated with cutaneous dysbiosis of S. aureus. These findings offer numerous avenues for new research.

Dietary Flavonoids and Adult Neurogenesis: Potential Implications for Brain Aging.

Adult neurogenesis deficiency has been proposed to be a common hallmark in different age-related neurodegenerative diseases. The administration of flavonoids is currently reported as a potentially beneficial strategy for preventing brain aging alterations, including adult neurogenesis decline. Flavonoids are a class of plant-derived dietary polyphenols that have drawn attention for their neuroprotective and pro-cognitive effects. Although they undergo extensive metabolism and localize in the brain at low concentrations, flavonoids are now believed to improve cerebral vasculature and interact with signal transduction cascades involved in the regulation of adult neurogenesis. Furthermore, many dietary flavonoids have been shown to reduce oxidative stress and neuroinflammation, improving the neuronal microenvironment where adult neurogenesis occurs. The overall goal of this review is to summarize the evidence supporting the role of flavonoids in modulating adult neurogenesis as well as to highlight how these dietary agents may be promising candidates in restoring healthy brain function during physiological and pathological aging.

Adherence to Antibiotic Prescription of Dental Patients: The Other Side of the Antimicrobial Resistance.

Since non-adherence to antibiotic therapy can cause several problems, including antimicrobial resistance (AMR) and treatment failures, the present study evaluated adherence to oral antibiotic therapy and AMR awareness among consecutively enrolled dental patients. Data concerning age, gender, socioeconomic status, education level, cohabitation, and general health were retrieved from medical records. AMR awareness was investigated through direct questions and adherence to antibiotic treatment was assessed through a modified Italian version of the Morisky medical scale-8 items. Participants' characteristics were analyzed in relation to treatment adherence and AMR, using a Χ2 independence test (significance level of α <0.1). Dental patients generally showed a low (51.82%) adherence to oral antibiotic therapy, and medium and high adherence was reported only by 29.37% and 18.81% of participants. Treatment adherence was similar in relation to participants' gender and age but significantly lower in subjects with only secondary school graduation and higher in participants with higher education levels. Non-cohabitants were significantly more adherent than cohabitants. AMR awareness was declared by 42.15% of males and 38.70% of females: 56.52% of dental patients aware of AMR were 18−38 years old, 35.20% were 39−59 years old, and 26.95% were aged between 60 and 80. Further studies are needed to develop adequate strategies, expanding dental patients' knowledge of AMR, thus optimizing the benefits and reducing the risks of antibiotic administration in dental patients.

Low-Density Lipoprotein Receptor-Related Protein 8 at the Crossroad between Cancer and Neurodegeneration.

The low-density-lipoprotein receptors represent a family of pleiotropic cell surface receptors involved in lipid homeostasis, cell migration, proliferation and differentiation. The family shares common structural features but also has significant differences mainly due to tissue-specific interactors and to peculiar proteolytic processing. Among the receptors in the family, recent studies place low-density lipoprotein receptor-related protein 8 (LRP8) at the center of both neurodegenerative and cancer-related pathways. From one side, its overexpression has been highlighted in many types of cancer including breast, gastric, prostate, lung and melanoma; from the other side, LRP8 has a potential role in neurodegeneration as apolipoprotein E (ApoE) and reelin receptor, which are, respectively, the major risk factor for developing Alzheimer's disease (AD) and the main driver of neuronal migration, and as a γ-secretase substrate, the main enzyme responsible for amyloid formation in AD. The present review analyzes the contributions of LDL receptors, specifically of LRP8, in both cancer and neurodegeneration, pointing out that depending on various interactions and peculiar processing, the receptor can contribute to both proliferative and neurodegenerative processes.

Bidirectional Control between Cholesterol Shuttle and Purine Signal at the Central Nervous System.

Recent studies have highlighted the mechanisms controlling the formation of cerebral cholesterol, which is synthesized in situ primarily by astrocytes, where it is loaded onto apolipoproteins and delivered to neurons and oligodendrocytes through interactions with specific lipoprotein receptors. The "cholesterol shuttle" is influenced by numerous proteins or carbohydrates, which mainly modulate the lipoprotein receptor activity, function and signaling. These molecules, provided with enzymatic/proteolytic activity leading to the formation of peptide fragments of different sizes and specific sequences, could be also responsible for machinery malfunctions, which are associated with neurological, neurodegenerative and neurodevelopmental disorders. In this context, we have pointed out that purines, ancestral molecules acting as signal molecules and neuromodulators at the central nervous system, can influence the homeostatic machinery of the cerebral cholesterol turnover and vice versa. Evidence gathered so far indicates that purine receptors, mainly the subtypes P2Y2, P2X7 and A2A, are involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer's and Niemann-Pick C diseases, by controlling the brain cholesterol homeostasis; in addition, alterations in cholesterol turnover can hinder the purine receptor function. Although the precise mechanisms of these interactions are currently poorly understood, the results here collected on cholesterol-purine reciprocal control could hopefully promote further research.

Cutaneous Ulcer Caused by Apixaban Treatment Is Resolved after Replacement with Dabigatran.

Nowadays, novel oral anticoagulants (NOACs) have shown improved safety profile and efficacy compared to vitamin K antagonists in the prevention of thromboembolic events occurring during different pathological conditions. However, there are concerns and safety issues, mostly related to adverse events following interactions with other drugs, in real-world practice. We report the case of an 83-year-old woman who developed a non-bleeding leg ulcer not caused by trauma or other evident pathological conditions after 10 days of treatment with apixaban 5 mg/q.d. She was switched from apixaban to dabigatran and the leg ulcer rapidly improved and completely cicatrized in 40 days. The resolution of the ulcer and the toleration of dabigatran therapy suggest an apixaban-specific reaction; however, the pathological mechanism of ulcer onset is currently unclear. Careful evaluation of hospital databases of Molise region (Southern Italy) hospitals identified two similar cases between 2019 and 2021. These cases underline the necessity of careful post-marketing surveillance, considering the rapidly increasing number of patients treated with NOACs and patient's risk factors such as old age, high polypharmacy rate, co-morbidities, and peculiar genetic background related to NOACs pharmacokinetic features.

Assessment of the Diagnostic Performance of a Novel SARS-CoV-2 Antigen Sealing Tube Test Strip (Colloidal Gold) as Point-of-Care Surveillance Test.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant outbreaks have highlighted the need of antigen-detecting rapid diagnostic tests (Ag-RDTs) that can be used at the point-of-care (POC). Although many Ag-RDTs have been approved for SARS-CoV-2 detection, studies demonstrating the clinical performance of Ag-RDTs against variants of concern, especially the new Omicron variant, are limited. The aim of this study was to evaluate the diagnostic sensitivity and specificity of the AMAZING COVID-19 Antigen Sealing Tube Test Strip (Colloidal Gold) in 584 early symptomatic and asymptomatic participants (age range 0-90 years). The performance of this Ag-RDT was assessed by comparing its results with reverse transcription RT-PCR (rRT-PCR). One hundred twenty positive samples were also analyzed with rRT-PCR to discriminate Omicron and Delta/Kappa variants (72.50% Omicron; 27.50% Delta/Kappa). Overall, the Ag-RDT showed high positive and negative percent values of 92.52% (95% CI, 86.61-95.95%) and 98.05% (95% CI, 96.41-98.95%), respectively, as well as an overall diagnostic accuracy of 96.92% (95% CI, 95.17-98.16%). Taken together, these data indicate that this inexpensive and simple-to-use Ag-RDT presents excellent analytical performance and can reliably detect Omicron and Delta/Kappa variants.

α-Synuclein filaments from transgenic mouse and human synucleinopathy-containing brains are major seed-competent species.

Assembled α-synuclein in nerve cells and glial cells is the defining pathological feature of neurodegenerative diseases called synucleinopathies. Seeds of α-synuclein can induce the assembly of monomeric protein. Here, we used sucrose gradient centrifugation and transiently transfected HEK 293T cells to identify the species of α-synuclein from the brains of homozygous, symptomatic mice transgenic for human mutant A53T α-synuclein (line M83) that seed aggregation. The most potent fractions contained Sarkosyl-insoluble assemblies enriched in filaments. We also analyzed six cases of idiopathic Parkinson's disease (PD), one case of familial PD, and six cases of multiple system atrophy (MSA) for their ability to induce α-synuclein aggregation. The MSA samples were more potent than those of idiopathic PD in seeding aggregation. We found that following sucrose gradient centrifugation, the most seed-competent fractions from PD and MSA brains are those that contain Sarkosyl-insoluble α-synuclein. The fractions differed between PD and MSA, consistent with the presence of distinct conformers of assembled α-synuclein in these different samples. We conclude that α-synuclein filaments are the main driving force for amplification and propagation of pathology in synucleinopathies.

Silver staining (Campbell-Switzer) of neuronal α-synuclein assemblies induced by multiple system atrophy and Parkinson's disease brain extracts in transgenic mice.

Synucleinopathies [Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA)] share filamentous α-synuclein assemblies in nerve cells and glial cells. We compared the abilities of brain extracts from MSA and PD patients to induce neuronal α-synuclein assembly and neurodegeneration following intracerebral injection in heterozygous mice transgenic for human mutant A53T α-synuclein. MSA extracts were more potent than PD extracts in inducing α-synuclein assembly and in causing neurodegeneration. MSA assemblies were Campbell-Switzer- and Gallyas-silver-positive, whereas PD assemblies were only Campbell-Switzer-positive, in confirmation of previous findings. However, induced α-synuclein inclusions were invariably Campbell-Switzer-positive and Gallyas-negative, irrespective of whether MSA or PD brain extracts were injected. The α-synuclein inclusions of non-injected homozygous mice transgenic for A53T α-synuclein were also Campbell-Switzer-positive and Gallyas-negative. These findings demonstrate that transgene expression and its intracellular environment dominated over the silver staining properties of the conformers of assembled α-synuclein.

Beta-sheet assembly of Tau and neurodegeneration in Drosophila melanogaster.

The assembly of Tau into abundant ß-sheet-rich filaments characterizes human tauopathies. A pathological pathway leading from monomeric to filamentous Tau is believed to be at the heart of these diseases. However, in Drosophila models of Tauopathy, neurodegeneration has been observed in the absence of abundant Tau filaments. Here we investigated the role of Tau assembly into ß-sheets by expressing wild-type and Δ306-311 human Tau-383 in the retina and brain of Drosophila. We analyzed both lines for eye abnormalities, brain vacuolization, Tau phosphorylation and assembly, as well as climbing activity and survival. Flies expressing wild-type Tau-383 showed MC-1 staining, Tau hyperphosphorylation, and neurodegeneration. By contrast, flies expressing Δ306-311 Tau-383 had less MC-1 staining, reduced Tau hyperphosphorylation, and no detectable neurodegeneration. Their climbing ability and lifespan were similar to those of nontransgenic flies. Fluorescence spectroscopy after addition of Thioflavin T, a dye that interacts with ß-sheets, showed no signal when Δ306-311 Tau-383 was incubated with heparin. These findings demonstrate that the assembly of Tau into ß-sheets is necessary for neurodegeneration.

Complexity and Selectivity of γ-Secretase Cleavage on Multiple Substrates: Consequences in Alzheimer's Disease and Cancer.

The processing of the amyloid-ß protein precursor (AßPP) by ß- and γ-secretases is a pivotal event in the genesis of Alzheimer's disease (AD). Besides familial mutations on the AßPP gene, or upon its overexpression, familial forms of AD are often caused by mutations or deletions in presenilin 1 (PSEN1) and 2 (PSEN2) genes: the catalytic components of the proteolytic enzyme γ-secretase (GS). The "amyloid hypothesis", modified over time, states that the aberrant processing of AßPP by GS induces the formation of specific neurotoxic soluble amyloid-ß (Aß) peptides which, in turn, cause neurodegeneration. This theory, however, has recently evidenced significant limitations and, in particular, the following issues are debated: 1) the concept and significance of presenilin's "gain of function" versus "loss of function"; and 2) the presence of several and various GS substrates, which interact with AßPP and may influence Aß formation. The latter consideration is suggestive: despite the increasing number of GS substrates so far identified, their reciprocal interaction with AßPP itself, even in the AD field, is significantly unexplored. On the other hand, GS is also an important pharmacological target in the cancer field; inhibitors or GS activity are investigated in clinical trials for treating different tumors. Furthermore, the function of AßPP and PSENs in brain development and in neuronal migration is well known. In this review, we focused on a specific subset of GS substrates that directly interact with AßPP and are involved in its proteolysis and signaling, by evaluating their role in neurodegeneration and in cell motility or proliferation, as a possible connection between AD and cancer.

Adiponectin as novel regulator of cell proliferation in human glioblastoma.

Adiponectin (Acrp30) is an adipocyte-secreted hormone with pleiotropic metabolic effects, whose reduced levels were related to development and progression of several malignancies. We looked at the presence of Acrp30 receptors in human glioblastomas (GBM), hypothesizing a role for Acrp30 also in this untreatable cancer. Here we demonstrate that human GBM express Acrp30 receptors (AdipoR1 and AdipoR2), which are often co-expressed in GBM samples (70% of the analyzed tumors). To investigate the effects of Acrp30 on GBM growth, we used human GBM cell lines U87-MG and U251, expressing both AdipoR1 and AdipoR2 receptors. In these cells, Acrp30 treatment inhibits DNA synthesis and cell proliferation rate, inducing arrest in G1 phase of the cell cycle. These effects were correlated to a sustained activation of ERK1/2 and Akt kinases, upon Acrp30 treatment. Our results suggest that Acrp30 may represent a novel endogenous negative regulator of GBM cell proliferation, to be evaluated for the possible development of novel pharmacological approaches.

Amyloid-ß protein precursor regulates phosphorylation and cellular compartmentalization of microtubule associated protein tau.

Tau is a multifunctional protein detected in different cellular compartments in neuronal and non-neuronal cells. When hyperphosphorylated and aggregated in atrophic neurons, tau is considered the culprit for neuronal death in familial and sporadic tauopathies. With regards to Alzheimer's disease (AD) pathogenesis, it is not yet established whether entangled tau represents a cause or a consequence of neurodegeneration. In fact, it is unquestionably accepted that amyloid-ß protein precursor (AßPP) plays a pivotal role in the genesis of the disease, and it is postulated that the formation of toxic amyloid-ß peptides from AßPP is the primary event that subsequently induces abnormal tau phosphorylation. In this work, we show that in the brain of AD patients there is an imbalance between the nuclear and the cytoskeletal pools of phospho-tau. We observed that in non-AD subjects, there is a stable pool of phospho-tau which remains strictly confined to neuronal nuclei, while nuclear localization of phospho-tau is significantly underrepresented in neurons of AD patients bearing neurofibrillary tangles. A specific phosphorylation of tau is required during mitosis in vitro and in vivo, likely via a Grb2-ERK1/2 signaling cascade. In differentiated neuronal A1 cells, the overexpression of AßPP modulates tau phosphorylation, altering the ratio between cytoskeletal and nuclear pools, and correlates with cell death. Altogether our data provide evidence that AßPP, in addition to amyloid formation, modulates the phosphorylation of tau and its subcellular compartmentalization, an event that may lead to the formation of neurofibrillary tangles and to neurodegeneration when occurring in postmitotic neurons.