An Antioxidant Enzyme Therapeutic for Sepsis

Mitochondrial electron transport chain disruption and oxidative stress in lipopolysaccharide-induced cardiac dysfunction in rats and mice

Sepsis, characterized by severe systemic inflammation and an excessive immune response to infection, is frequently triggered by bacterial endotoxins like lipopolysaccharide (LPS) from Gram-negative bacteria. Moreover, sepsis-induced cardiac dysfunction remains a leading cause of mortality. This study aims to elucidate the effects of LPS-induced cardiac injury on mitochondrial damage, oxidative stress, and subsequent cardiac dysfunction. LPS injections (in rats and mice) for three days (1.5 mg/kg) impacted the body weight and increased cardiac TNF-α. Additionally, it decreased mitochondrial complexes I and II activities while complexes III and IV remained unaffected. Disturbed in mitochondrial electron transport chain leads to an increase in reactive oxygen species (ROS). Indeed, LPS treatment significantly increased mitochondrial hydrogen peroxide production, reduced the activity of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase activity. This was accompanied by decreased mitochondrial and cytosolic sulfhydryl proteins and parallel increased cellular lipid peroxidation in the presence or absence of Fe2+. LPS-treated samples had increased glutathione s-transferase activity, which may be an attempt of the cell to remove toxic lipid peroxidation products. In a more acute Langendorff-perfused rat hearts, LPS infusion (0.5 μg/mL) induced a significant elevation in left ventricular end-diastolic pressure and a decrease in left ventricular developed pressure. These findings elucidate the harmful mitochondrial and oxidative effects of LPS in cardiac tissue and could help the development of targeted therapies to mitigate the adverse effects of sepsis-induced cardiac dysfunction.

Comparison of the effects between catalase and superoxide dismutase on regulating macrophage inflammatory response and protecting osteogenic function of periodontal ligament cells

BACKGROUND

Reactive oxygen species (ROS) have been confirmed closely associated with the pathological process of periodontitis, but the specific roles played by different ROS types are still to be investigated. Catalase (CAT) and Superoxide dismutase (SOD) specifically eliminate hydrogen peroxide (H2O2) and superoxide anion (O2•-), respectively. We for the first time compare the effects and mechanisms of CAT and SOD in protecting periodontal ligament cells (PDLCs) against oxidative damage, reducing the expression of macrophage inflammatory factors, and preserving the osteogenic differentiation function of PDLCs by modulating the inflammatory environment.

METHODS

CAT or SOD in combination with lipopolysaccharide (LPS) were added to the culture medium of RAW 264.7 and PDLCs. The intracellular ROS level, lipid peroxidation and DNA damage were observed by confocal microscope. Inflammation levels were assessed by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot. A co-culture system of macrophages and PDLCs was established, and the osteogenic differentiation of PDLCs was evaluated by alkaline phosphatase staining, alizarin red S staining, RT-qPCR and Western blot. Finally, differentially expressed genes (DEGs) in CAT and SOD were detected by RNA sequencing and the biological functions and signaling pathways involved were analyzed.

RESULTS

CAT or SOD can effectively inhibit intracellular ROS levels, lipid peroxidation and DNA damage, as well as increase the levels of antioxidative molecules and decrease the levels of inflammatory factors. SOD increased the levels of antioxidative molecules more strongly, while CAT reduced inflammatory factors more effectively. The RNA sequencing results indicate that CAT exhibits stronger inhibitory effects on inflammation-related signaling pathways, which could account for the observed differences.

CONCLUSIONS

In this study, we observed differential antioxidant and anti-inflammatory effects between CAT and SOD, which may be associated with CAT's better inhibition of the activation of inflammatory pathways. Our study will provide scientific references for the future development of highly selective ROS- scavenging antioxidant drugs.

An inhalable nanoparticle enabling virulence factor elimination and antibiotics delivery for pneumococcal pneumonia therapy

Streptococcus pneumoniae (S. pneumoniae) is a major cause of community-acquired pneumonia. Current standard clinical therapies mainly focus on combating S. pneumoniae through antibiotics. However, the limited delivery of antibiotics and the undetoxified hydrogen peroxide (H2O2) virulence factor secreted by S. pneumoniae impede the therapeutic outcomes. Here we report an inhalable catalase (CAT)-tannic acid (TA) nanoassembly for local antibiotic (levofloxacin) delivery and simultaneously neutralizing the secreted H2O2 virulence factors to treat pneumococcal pneumonia. After aerosol inhalation, the inhalable formulation (denoted as CT@LVX) effectively accumulates in lung tissues through TA-mediated mucoadhesion. CAT can reduce alveolar epithelial cells apoptosis by catalyzing the decomposition of accumulated H2O2 in the infected lung tissues. In synergy with antibiotic LVX-mediated S. pneumoniae elimination, CT@LVX significantly decreases lung injury companied with reduced inflammatory, resulting in 100 % survival of mice with pneumonia. In a clinically isolated S. pneumoniae strain-induced pneumonia mouse model, CT@LVX also shows superior outcomes compared to the traditional antibiotic treatment, highlighting its potential clinical application prospects.

Innovative Formulation Platform: Paving the Way for Superior Protein Therapeutics with Enhanced Efficacy and Broadened Applications

Protein therapeutics offer high therapeutic potency and specificity; the broader adoptions and development of protein therapeutics, however, have been constricted by their intrinsic limitations such as inadequate stability, immunogenicity, suboptimal pharmacokinetics and biodistribution, and off-target effects. This review describes a platform technology that formulates individual protein molecules with a thin formulation layer of crosslinked polymers, which confers the protein therapeutics with high activity, enhanced stability, controlled release capability, reduced immunogenicity, improved pharmacokinetics and biodistribution, and ability to cross the blood brain barriers. Based on currently approved protein therapeutics, this formulating platform affords the development of a vast family of superior protein therapeutics with improved efficacy and broadened indications at significantly reduced cost.

Multienzyme Active Nanozyme for Efficient Sepsis Therapy through Modulating Immune and Inflammation Inhibition

Sepsis, a life-threatening condition caused by a dysregulated immune response to infection, leads to systemic inflammation, immune dysfunction, and multiorgan damage. Various oxidoreductases play a very important role in balancing oxidative stress and modulating the immune response, but they are stored inconveniently, environmentally unstable, and expensive. Herein, we develop multifunctional artificial enzymes, CeO2 and Au/CeO2 nanozymes, exhibiting five distinct enzyme-like activities, namely, superoxide dismutase, catalase, glutathione peroxidase, peroxidase, and oxidase. These artificial enzymes have been used for the biocatalytic treatment of sepsis via inhibiting inflammation and modulating immune responses. These nanozymes significantly reduce reactive oxygen species and proinflammatory cytokines, achieving multiorgan protection. Notably, CeO2 and Au/CeO2 nanozymes with enzyme-mimicking activities can be particularly effective in restoring immunosuppression and maintaining homeostasis. The redox nanozyme offers a promising dual-protective strategy against sepsis-induced inflammation and organ dysfunction, paving the way for biocatalytic-based immunotherapies for sepsis and related inflammatory diseases.

Impact of Treatment with Antioxidants as an Adjuvant to Standard Therapy in Patients with Septic Shock: Analysis of the Correlation between Cytokine Storm and Oxidative Stress and Therapeutic Effects

Cellular homeostasis is lost or becomes dysfunctional during septic shock due to the activation of the inflammatory response and the deregulation of oxidative stress. Antioxidant therapy administered alongside standard treatment could restore this lost homeostasis. We included 131 patients with septic shock who were treated with standard treatment and vitamin C (Vit C), vitamin E (Vit E), N-acetylcysteine (NAC), or melatonin (MT), in a randomized trial. Organ damage quantified by Sequential Organ Failure Assessment (SOFA) score, and we determined levels of Interleukins (IL) IL1β, Tumor necrosis factor alpha (TNFα), IL-6, monocyte chemoattractant protein-1 (MCP-1), Transforming growth factor B (TGFβ), IL-4, IL-10, IL-12, and Interferon-γ (IFNγ). The SOFA score decreased in patients treated with Vit C, NAC, and MT. Patients treated with MT had statistically significantly reduced of IL-6, IL-8, MCP-1, and IL-10 levels. Lipid peroxidation, Nitrates and nitrites (NO3- and NO2-), glutathione reductase, and superoxide dismutase decreased after treatment with Vit C, Vit E, NAC, and MT. The levels of thiols recovered with the use of Vit E, and all patients treated with antioxidants maintained their selenium levels, in contrast with controls (p = 0.04). The findings regarding oxidative stress markers and cytokines after treatment with antioxidants allow us to consider to future the combined use of antioxidants in a randomized clinical trial with a larger sample to demonstrate the reproducibility of these beneficial effects.

UMI-77 Modulates the Complement Cascade Pathway and Inhibits Inflammatory Factor Storm in Sepsis Based on TMT Proteomics and Inflammation Array Glass Chip

Sepsis is a systemic inflammatory response syndrome caused by infection, which has no specific drug at present. UMI-77 can significantly improve the survival rate of septic mice; the detailed role of UMI-77 and its underlying mechanisms in sepsis are not clear. Inflammation array glass chip and proteomic analyses were performed to elucidate the latent mechanism of UMI-77 in the treatment of sepsis. The results showed that 7.0 mg/kg UMI-77 improved the 5 day survival rate in septic mice compared to the LPS group (60.964 vs 9.779%) and ameliorated the pathological conditions. Inflammation array glass chip analysis showed that sepsis treatment with UMI-77 may eventually through the suppression of the characteristic inflammatory storm-related cytokines such as KC, RANTES, LIX, IL-6, eotaxin, TARC, IL-1β, and so on. Proteomics analysis showed that 213 differential expression proteins and complement and coagulation cascades were significantly associated with the process for the UMI-77 treatment of sepsis. The top 10 proteins including Apoa2, Tgfb1, Serpinc1, Vtn, Apoa4, Cat, Hp, Serpinf2, Fgb, and Serpine1 were identified and verified, which play important roles in the mechanism of UMI-77 in the treatment of sepsis. Our findings indicate that UMI-77 exerts an antisepsis effect by modulating the complement cascade pathway and inhibiting inflammatory storm factors.

Functional chitosan gel coating enhances antimicrobial properties and osteogenesis of titanium alloy under persistent chronic inflammation

Titanium is widely used as surgical bone implants due to its excellent mechanical properties, corrosion resistance, and good biocompatibility. However, due to chronic inflammation and bacterial infections caused by titanium implants, they are still at risk of failure in interfacial integration of bone implants, severely limiting their broad clinical application. In this work, chitosan gels crosslinked with glutaraldehyde were prepared and successfully loaded with silver nanoparticles (nAg) and catalase nanocapsules (n (CAT)) to achieve functionalized coating on the surface of titanium alloy steel plates. Under chronic inflammatory conditions, n (CAT) significantly reduced the expression of macrophage tumor necrosis factor (TNF-α), increased the expression of osteoblast alkaline phosphatase (ALP) and osteopontin (OPN), and enhanced osteogenesis. At the same time, nAg inhibited the growth of S. aureus and E. coli. This work provides a general approach to functional coating of titanium alloy implants and other scaffolding materials.