Beneficial Effect of Tempol, a Membrane-Permeable Radical Scavenger, on Inflammation and Osteoarthritis in In Vitro Models

Innovative Nanotechnology in Drug Delivery Systems for Advanced Treatment of Posterior Segment Ocular Diseases

Funduscopic diseases, including diabetic retinopathy (DR) and age-related macular degeneration (AMD), significantly impact global visual health, leading to impaired vision and irreversible blindness. Delivering drugs to the posterior segment of the eye remains a challenge due to the presence of multiple physiological and anatomical barriers. Conventional drug delivery methods often prove ineffective and may cause side effects. Nanomaterials, characterized by their small size, large surface area, tunable properties, and biocompatibility, enhance the permeability, stability, and targeting of drugs. Ocular nanomaterials encompass a wide range, including lipid nanomaterials, polymer nanomaterials, metal nanomaterials, carbon nanomaterials, quantum dot nanomaterials, and so on. These innovative materials, often combined with hydrogels and exosomes, are engineered to address multiple mechanisms, including macrophage polarization, reactive oxygen species (ROS) scavenging, and anti-vascular endothelial growth factor (VEGF). Compared to conventional modalities, nanomedicines achieve regulated and sustained delivery, reduced administration frequency, prolonged drug action, and minimized side effects. This study delves into the obstacles encountered in drug delivery to the posterior segment and highlights the progress facilitated by nanomedicine. Prospectively, these findings pave the way for next-generation ocular drug delivery systems and deeper clinical research, aiming to refine treatments, alleviate the burden on patients, and ultimately improve visual health globally.

Reactive oxygen species-scavenging nanomaterials for the prevention and treatment of age-related diseases

With increasing proportion of the elderly in the population, age-related diseases (ARD) lead to a considerable healthcare burden to society. Prevention and treatment of ARD can decrease the negative impact of aging and the burden of disease. The aging rate is closely associated with the production of high levels of reactive oxygen species (ROS). ROS-mediated oxidative stress in aging triggers aging-related changes through lipid peroxidation, protein oxidation, and DNA oxidation. Antioxidants can control autoxidation by scavenging free radicals or inhibiting their formation, thereby reducing oxidative stress. Benefiting from significant advances in nanotechnology, a large number of nanomaterials with ROS-scavenging capabilities have been developed. ROS-scavenging nanomaterials can be divided into two categories: nanomaterials as carriers for delivering ROS-scavenging drugs, and nanomaterials themselves with ROS-scavenging activity. This study summarizes the current advances in ROS-scavenging nanomaterials for prevention and treatment of ARD, highlights the potential mechanisms of the nanomaterials used and discusses the challenges and prospects for their applications.

Novel Findings on CCR1 Receptor in CNS Disorders: A Pathogenic Marker Useful in Controlling Neuroimmune and Neuroinflammatory Mechanisms in Parkinson's Disease

Parkinson's disease (PD) is recognized as the second most common neurodegenerative disease worldwide. Even if PD etiopathogenesis is not yet fully understood, in recent years, it has been advanced that a chronic state of inflammation could play a decisive role in the development of this pathology, establishing the close link between PD and neuroinflammation. In the broad panorama of inflammation and its several signaling pathways, the C-C chemokine receptor type 1 (CCR1) could play a key pathogenic role in PD progression, and could constitute a valuable target for the development of innovative anti-PD therapies. In this study, we probed the neuroprotective properties of the CCR1 antagonist BX471 compound in a mouse model of MPTP-induced nigrostriatal degeneration. BX471 treatments were performed intraperitoneally at a dose of 3 mg/kg, 10 mg/kg, and 30 mg/kg, starting 24 h after the last injection of MPTP and continuing for 7 days. From our data, BX471 treatment strongly blocked CCR1 and, as a result, decreased PD features, also reducing the neuroinflammatory state by regulating glial activation, NF-κB pathway, proinflammatory enzymes, and cytokines overexpression. Moreover, we showed that BX471's antagonistic action on CCR1 reduced the infiltration of immune cells, including mast cells and lymphocyte T activation. In addition, biochemical analyses carried out on serum revealed a considerable increase in circulating levels of CCR1 following MPTP-induced PD. In light of these findings, CCR1 could represent a useful pathological marker of PD, and its targeting could be a worthy candidate for the future development of new immunotherapies against PD.

Rebalancing NOX2/Nrf2 to limit inflammation and oxidative stress across gut-brain axis in migraine

Migraine is one of the most common neurological illnesses, and it is characterized by complicated neurobiology. It was confirmed the influence of inflammation and oxidative stress in migraines and also in distal organs such as the intestine. Indeed, the constant bidirectional communication between the Central Nervous System (CNS) and the gastrointestinal (GI) tract, known as the gut-brain axis, has become an attractive target involved in different human disorders. Herein, we explored the role of NADPH oxidase 2 (NOX2) in nitroglycerin (NTG)-induced migraine in mice models to discover the mechanism by which, during migraine attack, oxidative stress is sustained within trigeminal neurons and GI. Considering the inverse relationship between NOX2 and Nrf2, Nrf2 upregulation seems to be a promising approach to decrease NOX2 expression and consequently limit oxidative stress and inflammation spread in neurological and non-neurological diseases. With this aim, we exploited tempol's Nrf2-inducer ability to better understand the involvement of Nrf2/NOX2 axis in migraine and associated GI comorbidities. Behavioral tests confirmed that tempol, in a dose-dependent manner, moderated clinical signs of migraine and abdominal pain. Moreover, we demonstrated that the decrease in migraine-related symptomatology was strongly linked to the modulation of Nrf2/NOX2 signaling pathway in the brain and colon. In the brain, the rebalancing of Nrf2/NOX2 prevented neuronal loss, decreased glia reactivity while inhibiting NF-κB and NLRP3 inflammasome activation. In the colon, Nrf2 upregulation and consequent NOX2 decrease reduced the histological damage, mast cells infiltration as well as tumor necrosis factor (TNF)-α and interleukin (IL)-1β release. Furthermore, the attenuation of inflammation and oxidative stress led to the restoration of the intestinal barrier through TJs replacement. Taken as a whole, data suggested that the regulation of Nrf2/NOX2 balance is a successful way to reduce neurological and related intestinal impairments during migraine and could be of relevance for migraine-like attacks in humans.

Glucose fluctuations aggravated the late sodium current induced ventricular arrhythmias via the activation of ROS/CaMKII pathway

BACKGROUND

Recent evidence revealed that glucose fluctuation might be more likely to cause arrhythmia than persistent hyperglycemia, whereas its mechanisms were elusive. We aimed to investigate the effect of glucose fluctuation on the occurrence of ventricular arrhythmia and its mechanism.

METHODS

Streptozotocin (STZ) induced diabetic rats were randomized to five groups: the controlled blood glucose (C-STZ) group, uncontrolled blood glucose (U-STZ) group, fluctuated blood glucose (GF-STZ) group, and GF-STZ rats with 100 mg/kg Tempol (GF-STZ + Tempol) group or with 5 mg/kg KN93 (GF-STZ + KN93) group. Six weeks later, the susceptibility of ventricular arrhythmias and the electrophysiological dysfunctions of ventricular myocytes were evaluated using electrocardiogram and patch-clamp technique, respectively. The levels of reactive oxygen species (ROS) and oxidized CaMKII (ox-CaMKII) were determined by fluorescence assay and Western blot, respectively. Neonatal rat cardiomyocytes and H9C2 cells in vitro were used to explore the underlying mechanisms.

RESULTS

The induction rate of ventricular arrhythmias was 10%, 55%, and 90% in C-STZ group, U-STZ group, and GF-STZ group, respectively (P < 0.05). The electrophysiological dysfunctions of ventricular myocytes, including action potential duration at repolarization of 90% (APD90), APD90 short-term variability (APD90-STV), late sodium current (INa-L), early after depolarization (EAD) and delayed after depolarizations (DAD), as well as the levels of ROS and ox-CaMKII, were significantly increased in GF-STZ group. In vivo and ex vivo, inhibition of ROS or ox-CaMKII reversed these effects. Inhibition of INa-L also significantly alleviated the electrophysiological dysfunctions. In vitro, inhibition of ROS increase could significantly decrease the ox-CaMKII activation induced by glucose fluctuations.

CONCLUSIONS

Glucose fluctuations aggravated the INa-L induced ventricular arrhythmias though the activation of ROS/CaMKII pathway.

An in vitro model for osteoarthritis using long-cultured inflammatory human macrophages repeatedly stimulated with TLR agonists

Osteoarthritis (OA) is characterized by an abundance of inflammatory M1-like macrophages damaging local tissues. The search for new potential drugs for OA suffers from the lack of appropriate methods of long-lasting inflammation. Here we developed and characterized an in vitro protocol of long-lasting culture of primary human monocyte-derived macrophages differentiated with a combination of M-CSF+GM-CSF that optimally supported long-cultured macrophages (LC-Mϕs) for up to 15 days, unlike their single use. Macrophages repeatedly stimulated for 15 days with the TLR2 ligand Pam3CSK4 (LCS-Mϕs), showed sustained levels over time of IL-6, CCL2, and CXCL8, inflammatory mediators that were also detected in the synovial fluids of OA patients. Furthermore, macrophages isolated from the synovia of two OA patients showed an expression profile of inflammation-related genes similar to that of LCS-Mϕs, validating our protocol as a model of chronically activated inflammatory macrophages. Next, to confirm that these LCS-Mϕs could be modulated by anti-inflammatory compounds, we employed dexamethasone and/or celecoxib, two drugs widely used in OA treatment, that significantly inhibited the production of inflammatory mediators. This easy-to-use in vitro protocol of long-lasting inflammation with primary human macrophages could be useful for the screening of new compounds to improve the therapy of inflammatory disorders.

Exercise induces superoxide and NOX4 contribution in endothelium-dependent dilation in coronary arterioles from a swine model of chronic myocardial ischemia

Exercise training is an effective, nonpharmacologic therapy and preventative measure for ischemic heart disease. While recent studies have examined reactive oxygen species (ROS) as mediators of exercise training-enhanced coronary blood flow, specific oxidants and their sources have yet to be fully elucidated. We investigated the hypothesis that NADPH oxidase (NOX)-derived superoxide anion would contribute to vasodilation effects in the coronary microcirculation of swine and that these effects would be impaired by chronic ischemia and rescued with exercise training. Adult Yucatan miniature swine were instrumented with an ameroid occluder around the proximal left circumflex coronary artery, resulting in a collateral-dependent myocardial region. Eight weeks post-operatively, swine were randomly assigned to either a sedentary or exercise training (treadmill run; 5 days/week for 14 weeks) protocol. Coronary arterioles were isolated from nonoccluded and collateral-dependent myocardial regions and pressure myography was performed. Exercise training resulted in enhanced endothelium-dependent dilation after occlusion. Scavenging of superoxide via the superoxide dismutase (SOD)-mimetic, tempol, attenuated dilation in both nonoccluded and collateral-dependent arterioles of exercise-trained, but not sedentary swine. NOX1/4 inhibition with GKT136901 attenuated dilation after exercise training but only in collateral-dependent arterioles. High performance liquid chromatography revealed that neither ischemia nor exercise training significantly altered basal or bradykinin-stimulated superoxide levels. Furthermore, superoxide production was not attributable to NOX isoforms nor mitochondria. Immunoblot analyses revealed significantly decreased NOX2 protein after exercise with no differences in NOX1, NOX4, p22phox, SOD proteins. Taken together, these data provide evidence that superoxide and NOX4 independently contribute to enhanced endothelium-dependent dilation following exercise training.

Terfezia boudieri and Terfezia claveryi inhibit the LPS/IFN-γ-mediated inflammation in RAW 264.7 macrophages through an Nrf2-independent mechanism

Desert truffles have been used as traditional treatments for numerous inflammatory disorders. However, the molecular mechanisms underlying their anti-inflammatory effects in RAW 264.7 macrophages have yet to be fully elucidated. The present study investigated the anti-inflammatory activities of two main desert truffles, Terfezia boudieri and T. claveryi, and the underlying mechanisms associated with their anti-inflammatory activities in RAW 264.7 macrophages stimulated with lipopolysaccharide/interferon-gamma (LPS/IFN-γ). Our results demonstrated that treatment with T. boudieri and T. claveryi extracts effectively suppressed the inflammatory response in LPS/IFN-γ-stimulated RAW 264.7 macrophages. Specifically, T. boudieri extract was found to reduce the production of nitric oxide and inhibit the expression of various pro-inflammatory markers, including inducible nitric oxide synthase, cyclooxygenase-2 (COX-2), tumor necrosis factor-α, and interleukin-6 (IL-6) at both the mRNA and protein levels. Similarly, T. claveryi extract exhibited comparable inhibitory effects, except for the expression of IL-6 and COX-2 at the protein level, where no significant effect was observed. Moreover, both studied extracts significantly downregulated the microRNA expression levels of miR-21, miR-146a, and miR-155, suggesting that T. boudieri and T. claveryi suppress the inflammatory response in LPS/IFN-γ-stimulated RAW 264.7 cells through an epigenetic mechanism. Furthermore, our study reveals a new mechanism for the anti-inflammatory properties of desert truffle extracts. We show for the first time that Terfezia extracts do not rely on the nuclear factor erythroid 2-related factor 2 pathway, previously linked to anti-inflammatory responses. This expands our understanding of natural product anti-inflammatory mechanisms and could have important implications for developing new therapies. To account for differences in truffle effects, extracts prepared were subjected to secondary metabolites profiling using UPLC-MS. UPLC-MS led to the annotation of 87 secondary metabolites belonging to various classes, including amino acids, carbohydrates, alkaloids, amides, fatty acids, sterols, and phenolic compounds. Therefore, these results indicate that T. boudieri and T. claveryi exhibit anti-inflammatory activities through suppressing multiple inflammatory mediators and cytokines and may be potential anti-inflammatory agents.

Efficacy of the Radical Scavenger, Tempol, to Reduce Inflammation and Oxidative Stress in a Murine Model of Atopic Dermatitis

Atopic dermatitis (AD) is the most common chronically relapsing inflammatory skin disease, predominantly common in children; it is characterized by an eczematous pattern generally referable to skin dryness and itchy papules that become excoriated and lichenified in the more advanced stages of the disease. Although the pathophysiology of AD is not completely understood, numerous studies have demonstrated the complex interaction between genetic, immunological, and environmental factors, which acts to disrupt skin barrier function. Free radicals play a key role by directly damaging skin structure, inducing inflammation and weakening of the skin barrier. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) is a membrane-permeable radical scavenger, known to be a stable nitroxide, which exhibits excellent antioxidant effects in several human disorders, such as osteoarthritis and inflammatory bowel diseases. Considering the few existing studies on dermatological pathologies, this study aimed to evaluate tempol, in a cream formulation, in a murine model of AD. Dermatitis was induced in mice via dorsal skin application of 0.5% Oxazolone, three times a week for two weeks. After induction, mice were treated with tempol-based cream for another two weeks at three different doses of 0.5%, 1% and 2%. Our results demonstrated the ability of tempol, at the highest percentages, to counteract AD by reducing the histological damage, decreasing mast cell infiltration, and improving the skin barrier properties, by restoring the tight junction (TJs) and filaggrin. Moreover, tempol, at 1% and 2%, was able to modulate inflammation by reducing the nuclear factor kappa-light-chain-enhancer of the activated B cell (NF-κB) pathway, as well as tumor necrosis factor (TNF)-α and interleukin (IL)-1β expression. Topical treatment also attenuated oxidative stress by modulating nuclear factor erythroid 2-related factor 2 (Nrf2), manganese superoxide dismutase (MnSOD), and heme oxygenase I (HO-1) expression levels. The obtained results demonstrate the numerous advantages provided by the topical administration of a tempol-based cream formulation, in reducing inflammation and oxidative stress through modulation of the NF-κB/Nrf2 signaling pathways. Therefore, tempol could represent an alternative anti-atopic approach to treating AD, thereby improving skin barrier function.

Mussel-Based Biomimetic Strategies in Musculoskeletal Disorder Treatment: From Synthesis Principles to Diverse Applications

Musculoskeletal disorders are the second leading cause of disability worldwide, posing a huge global burden to the public sanitation system. Currently, tissue engineering-based approaches act as effective strategies, which are, however, challenging in limited application scenarios. Mussel-based biomimetic materials, exhibit numerous unique properties such as intense adhesion, biocompatibility, moisture resistance, and injectability, to name only a few, and have attracted extensive research interest. In particular, featuring state-of-the-art properties, mussel-inspired biomaterials have been widely explored in innumerable musculoskeletal disorder treatments including osteochondral defects, osteosarcoma, osteoarthritis, ligament rupture, and osteoporosis. Nevertheless, a comprehensive and timely discussion of their applications in musculoskeletal disorders is insufficient. In this review, we emphasize on (1) the main categories and characteristics of mussel foot proteins and their fundamental mechanisms for the spectacular adhesion in mussels; (2) the diverse synthetic methods and modification of various polymers; and (3) the emerging applications of mussel-biomimetic materials, the future perspectives, and challenges, especially in the area of musculoskeletal disorder. We envision that this review will provide a unique and insightful perspective to improve the development of a new generation of mussel biomimetic strategies.

Emerging ROS-Modulating Technologies for Augmentation of the Wound Healing Process

Reactive oxygen species (ROS) is considered a double-edged sword. The slightly elevated level of ROS helps in wound healing by inhibiting microbial infection. In contrast, excessive ROS levels in the wound site show deleterious effects on wound healing by extending the inflammation phase. Understanding the ROS-mediated molecular and biomolecular mechanisms and their effect on cellular homeostasis and inflammation thus substantially improves the possibility of exogenously augmenting and manipulating wound healing with the emerging antioxidant therapeutics. This review comprehensively delves into the relationship between ROS and critical phases of wound healing and the processes underpinning antioxidant therapies. The manuscript also discusses cutting-edge antioxidant therapeutics that act via ROS scavenging to enhance chronic wound healing.

Recent Advances in Reactive Oxygen Species (ROS)-Responsive Polyfunctional Nanosystems 3.0 for the Treatment of Osteoarthritis

Osteoarthritis (OA) is an inflammatory and degenerative joint disease with severe effects on individuals, society, and the economy that affects millions of elderly people around the world. To date, there are no effective treatments for OA; however, there are some treatments that slow or prevent its progression. Polyfunctional nanosystems have many advantages, such as controlled release, targeted therapy and high loading rate, and have been widely used in OA treatment. Previous mechanistic studies have revealed that inflammation and ROS are interrelated, and a large number of studies have demonstrated that ROS play an important role in different types of OA development. In this review article, we summarize third-generation ROS-sensitive nanomaterials that scavenge excessive ROS from chondrocytes and osteoclasts in vivo. We only focus on polymer-based nanoparticles (NPs) and do not review the effects of drug-loaded or heavy metal NPs. Mounting evidence suggests that polyfunctional nanosystems will be a promising therapeutic strategy in OA therapy due to their unique characteristics of being sensitive to changes in the internal environment.

Evaluation of a Gel Containing a Propionibacterium Extract in an In Vivo Model of Wound Healing

Inappropriate wound healing (WH) management can cause significant comorbidities, especially in patients affected by chronic and metabolic diseases, such as diabetes. WH involves several different, partially overlapping processes, including hemostasis, inflammation, cell proliferation, and remodeling. Oxidative stress in WH contributes to WH impairment because of the overexpression of radical oxygen species (ROS) and nitrogen species (RNS). This study aimed to evaluate the in vitro antioxidative action of a gel containing a Propionibacterium extract (Emorsan® Gel) and assess its skin re-epithelialization properties in a mouse model of WH. The scavenging effects of the bacterial extract were assessed in vitro through the ABTS and DPPH assays and in L-929 murine fibroblasts. The effects of the Emorsan® Gel were studied in vivo in a murine model of WH. After WH induction, mice were treated daily with vehicle or Emorsan® Gel for 6 or 12 days. According to the in vitro tests, the Propionibacterium extract exerted an inhibitory effect on ROS and RNS, consequently leading to the reduction in malondialdehyde (MDA) and nitrite levels. Before proceeding with the in vivo study, the Emorsan® Gel was verified to be unabsorbed. Therefore, the observed effects could be ascribed to a local action. The results obtained in vivo showed that through local reduction of oxidative stress and inflammation (IL-1β, TNF-α), the Emorsan® Gel significantly reduced the infiltration of mast cells into the injured wound, leading to the amelioration of symptoms such as itch and skin irritation. Therefore, the Emorsan® Gel improved the speed and percentage of wound area closure by improving the tissue remodeling process, prompting vascular–endothelial growth factor (VEGF) and transforming growth factor (TGF)- β production and reducing the expression of adhesion molecules. Emorsan® Gel, by its ability to inhibit free radicals, could reduce local inflammation and oxidative stress, thus enhancing the speed of wound healing.

SCFA Treatment Alleviates Pathological Signs of Migraine and Related Intestinal Alterations in a Mouse Model of NTG-Induced Migraine

Background: There is a growing realization that the gut–brain axis signaling is critical for maintaining the health and homeostasis of the Central Nervous System (CNS) and the intestinal environment. The role of Short-Chain Fatty Acids (SCFAs), such as Sodium Propionate (SP) and Sodium Butyrate (SB), has been reported to counteract inflammation activation in the central and Enteric Nervous System (ENS). Methods: In this study, we evaluated the role of the SCFAs in regulating the pathophysiology of migraine and correlated dysregulations in the gut environment in a mouse model of Nitroglycerine (NTG)-induced migraine. Results: We showed that, following behavioral tests evaluating pain and photophobia, the SP and SB treatments attenuated pain attacks provoked by NTG. Moreover, treatments with both SCFAs reduced histological damage in the trigeminal nerve nucleus and decreased the expression of proinflammatory mediators. Ileum evaluation following NTG injection reported that SCFA treatments importantly restored intestinal mucosa alterations, as well as the release of neurotransmitters in the ENS. Conclusions: Taken together, these results provide evidence that SCFAs exert powerful effects, preventing inflammation through the gut–brain axis, suggesting a new insight into the potential application of SCFAs as novel supportive therapies for migraine and correlated intestinal alterations.

Phytochemical Analysis and Anti-Inflammatory and Anti-Osteoarthritic Bioactive Potential of Verbascum thapsus L. (Scrophulariaceae) Leaf Extract Evaluated in Two In Vitro Models of Inflammation and Osteoarthritis

Osteoarthritis (OA) is a complex disease, source of pain and disability that affects millions of people worldwide. OA etiology is complex, multifactorial and joint-specific, with genetic, biological and biomechanical components. Recently, several studies have suggested a potential adjuvant role for natural extracts on OA progression, in terms of moderating chondrocyte inflammation and following cartilage injury, thus resulting in an overall improvement of joint pain. In this study, we first analyzed the phenylethanoid glycosides profile and the total amount of polyphenols present in a leaf aqueous extract of Verbascum thapsus L. We then investigated the anti-inflammatory and anti-osteoarthritic bioactive potential of the extract in murine monocyte/macrophage-like cells (RAW 264.7) and in human chondrocyte cells (HC), by gene expression analysis of specifics inflammatory cytokines, pro-inflammatory enzymes and metalloproteases. Six phenylethanoid glycosides were identified and the total phenolic content was 124.0 ± 0.7 mg gallic acid equivalent (GAE)/g of extract. The biological investigation showed that the extract is able to significantly decrease most of the cellular inflammatory markers, compared to both control cells and cells treated with Harpagophytum procumbens (Burch.) DC. ex Meisn, used as a positive control. Verbascum thapsus leaf aqueous extract has the potential to moderate the inflammatory response, representing an innovative possible approach for the inflammatory joint disease treatment.

Reactive-oxygen-species-scavenging nanomaterials for resolving inflammation

Reactive oxygen species (ROS) mediate multiple physiological functions; however, the over-accumulation of ROS causes premature aging and/or death and is associated with various inflammatory conditions. Nevertheless, there are limited clinical treatment options that are currently available. The good news is that owing to the considerable advances in nanoscience, multiple types of nanomaterials with unique ROS-scavenging abilities that influence the temporospatial dynamic behaviors of ROS in biological systems have been developed. This has led to the emergence of next-generation nanomaterial-controlled strategies aimed at ameliorating ROS-related inflammatory conditions. Accordingly, herein we reviewed recent progress in research on nanotherapy based on ROS scavenging. The underlying mechanisms of the employed nanomaterials are emphasized. Furthermore, important issues in developing cross-disciplinary nanomedicine-based strategies for ROS-based inflammatory conditions are discussed. Our review of this increasing interdisciplinary field will benefit ongoing studies and clinical applications of nanomedicine based on ROS scavenging.