Endogenous Activity Research Articles

Visualization of an Endogenous Mitochondrial Azoreductase Activity under Normoxic Conditions Using a Naphthalimide Azo-Based Fluorogenic Probe.

In this paper, we demonstrate the existence of an endogenous mitochondrial azoreductase (AzoR) activity that can induce the cleavage of N═N double bonds of azobenzene compounds under normoxic conditions. To this end, 100% OFF-ON azo-based fluorogenic probes derived from 4-amino-1,8-naphthalimide fluorophores were synthesized and evaluated. The in vitro study conducted with other endogenous reducing agents of the cell, including reductases, demonstrated both the efficacy and the selectivity of the probe for AzoR. Confocal experiments with the probe revealed an AzoR activity in the mitochondria of living cells under normal oxygenation conditions, and we were able to demonstrate that this endogenous AzoR activity appears to be expressed at different levels across different cell lines. This discovery provides crucial information for our understanding of the biochemical processes occurring within the mitochondria. It thus contributes to a better understanding of its function, which is implicated in numerous pathologies.

Evaluation of Antioxidants’ Ability to Enhance Hyaluronic Acid-Based Topical Moisturizers

Introduction: Hyaluronic acid (HA) is a unique molecule with multiple biological activities. In skin, HA plays an essential role as a humectant, capable of binding up to 1000 times its mass with water, leading to both skin moisturization and extracellular matrix rigidity. HA concentration and synthesis decreases significantly in aging skin, due to exogenous and endogenous factors, including photoaging and HA metabolism, respectively. A key driver for HA degradation and decrease in concentration is mediated via the induction of reactive oxygen species (ROS) and other free radicals. In this study, we evaluate antioxidant ingredients essential in the development of next-generation multi-weight HA-based topical formulations aimed at leveraging hyaluronic acid’s ability to maximize anti-aging properties. Methods: Two antioxidants, glycine saponin and glycyrrhetinic acid, were evaluated for stimulation of endogenous HA production and inhibition of endogenous hyaluronidase activity in an in vitro and cell-free assay. Results: The antioxidant glycine saponin induced endogenous HA synthesis in keratinocytes, while the antioxidant glycyrrhetinic acid demonstrated an approximately 54% reduction of hyaluronidase activity for the HA-degrading enzyme HYAL1. Conclusion: This study demonstrates the ability of two antioxidants (glycine saponin and glycyrrhetinic acid, essential in the development of the next generation of multi-weight HA plus antioxidant complex-based topical skin formulations) to limit the signs of aging skin, addressing limitations of many currently available topical HA-based formulations.

Significantly Enhanced Improvement in Dryness, Roughness, Fine Lines and Radiance Following Daily Use of a Novel Multi-Weight Hyaluronic Acid Plus Antioxidant Complex-Based Lotion Compared to a Single-Weight HA Plus Ceramide-Based Lotion

Introduction: Hyaluronic acid (HA) has become a commonly used ingredient in many topical moisturizing products due to its strong humectant properties and essential role in skin hydration; however, limitations of delivery of HA to only the surface of skin has hindered leveraging the full capacity of HA biology necessary for skin rejuvenation. Here we describe the head-to-head clinical comparison of a novel multi-weight HA plus antioxidant complex-based lotion with SPF 30 and a single-weight plus ceramide-based lotion with SPF 30 for clinical efficacy on dryness, roughness, fine facial lines, and radiance following daily use. Methods: A double-blind comparative study was conducted on 70 female subjects (n=35, multi-weight HA plus antioxidant complex-based lotion with SPF 30; n=35, single-weight plus ceramide-based lotion with SPF 30) ages 25 to 65 years with mild to moderate facial dryness and visible fine lines and wrinkles, including subjects with Fitzpatrick Skin Types I-VI, with 20% having Fitzpatrick Skin Types V-VI. Clinical grading of the face including dryness, roughness, and fine lines were assessed at baseline, 30 minutes, 2 weeks, 4 weeks, and 8 weeks after once daily application in the morning. Visible, cross-polarized (X-Pol), parallel-polarized (P-Pol) and UV fluorescence clinical images were acquired for each time point. X-Pol and P-Pol images were used to quantify skin radiance. Results: Daily use of the multi-weight HA plus antioxidant complex-based lotion with SPF 30 demonstrated significant improvements in all clinical grading assessments of dryness, fine lines, and wrinkles as early as Week 2 compared to baseline. Improvements in visible dryness (Week 2), roughness (Week 2), and fine lines (Week 8) were greater for the multi-weight HA plus antioxidant complex-based lotion with SPF 30 compared to the single-weight HA plus ceramide-based lotion with SPF 30, with overall statistical significance across all three parameters assessed favoring the multi-weight HA plus antioxidant complex-based lotion with SPF 30. For radiance, daily use of the multi-weight HA plus antioxidant complex-based lotion with SPF 30 demonstrated significant increase in radiance at Week 4 compared with baseline, while the single-weight HA plus ceramide-based lotion did not show any improvement in skin radiance compared with baseline. Conclusions: The marked improvements in dryness, roughness, fine lines, and radiance following daily utilization of the multi-weight HA plus antioxidant complex-based lotion with SPF 30 may be attributed to the inherent properties of HA. These improvements may be further attributed to the ability of multi-weight HAs to moisturize the skin surface and penetrate the upper surface layers of the skin, combined with the added benefits of key antioxidants, including glycine saponin and glycyrrhetinic acid, which have been previously shown to induce endogenous HA synthesis and inhibit endogenous hyaluronidase activity in vitro, respectively.

Complete Biochemical Characterization of Pantaphos Biosynthesis Highlights an Unusual Role for a SAM-Dependent Methyltransferase.

Pantaphos is small molecule virulence factor made by the plant pathogen Pantoea ananatis. An 11 gene operon, designated hvr for high virulence, is required for production of this phosphonic acid natural product, but the metabolic steps used in its production have yet to be established. Herein, we determine the complete biosynthetic pathway using a combination of bioinformatics, in vitro biochemistry and in vivo heterologous expression. Only 6 of the 11 hvr genes are needed to produce pantaphos, while a seventh is likely to be required for export. Surprisingly, the pathway involves a series of O-methylated intermediates, which are then hydrolyzed to produce the final product. The methylated intermediates are produced by an irreversible S-adenosylmethione (SAM)-dependent methyltransferase that is required to drive a thermodynamically unfavorable dehydration in the preceding step, a function not previously attributed to members of this enzyme class. Methylation of pantaphos by the same enzyme is also likely to limit its toxicity in the producing organism. The pathway also involves a novel flavin-dependent monooxygenase that differs from homologous proteins due to its endogenous flavin-reductase activity. Heterologous production of pantaphos by Escherichia coli strains expressing the minimal gene set strongly supports the in vitro biochemical data.

Changes in Cortisol and in Oxidative/Nitrosative Stress Indicators after ADHD Treatment.

Although ADHD is one of the most prevalent diseases during childhood, we still do not know its precise origin; oxidative/nitrosative stress and the hypothalamic-pituitary-adrenal axis are suggested contributors. Methylphenidate, among others, is the main drug used in ADHD patients, but its effects on relevant markers and structures remain unclear. This study, involving 59 patients diagnosed with ADHD according to DSM-5 criteria, aimed to assess changes in cortisol levels (using cortisol awakening response, CAR) and oxidative/nitrosative status with the treatment. Blood samples before and 3 months after treatment with methylphenidate were used to measure oxidative and inflammatory markers, as well as the endogenous antioxidant activity, while saliva samples tracked cortisol awakening response (CAR). The results showed a treatment-related improvement in the redox profile, with the reduction in advanced oxidation protein products (AOPP), lipid peroxidation (LPO), and nitrite plus nitrate (NOx) levels, and the increase in the enzymatic activities of glutathione reductase (GRd) and catalase (CAT). Moreover, the area under the curve (AUC) of CAR increased significantly, indicating increased reactivity of the HPA axis. These results support, for the first time, the involvement of the endogenous antioxidant system in the pathophysiology of ADHD.

Endogenous Signaling Molecule Activating (ESMA) CARs: A Novel CAR Design Showing a Favorable Risk to Potency Ratio for the Treatment of Triple Negative Breast Cancer.

As chimeric antigen receptor (CAR) T cell therapy continues to gain attention as a valuable treatment option against different cancers, strategies to improve its potency and decrease the side effects associated with this therapy have become increasingly relevant. Herein, we report an alternative CAR design that incorporates transmembrane domains with the ability to recruit endogenous signaling molecules, eliminating the need for stimulatory signals within the CAR structure. These endogenous signaling molecule activating (ESMA) CARs triggered robust cytotoxic activity and proliferation of the T cells when directed against the triple-negative breast cancer (TNBC) cell line MDA-MB-231 while exhibiting reduced cytokine secretion and exhaustion marker expression compared to their cognate standard second generation CARs. In a NOD SCID Gamma (NSG) MDA-MB-231 xenograft mouse model, the lead candidate maintained longitudinal therapeutic efficacy and an enhanced T cell memory phenotype. Profound tumor infiltration by activated T cells repressed tumor growth, further manifesting the proliferative capacity of the ESMA CAR T cell therapy. Consequently, ESMA CAR T cells entail promising features for improved clinical outcome as a solid tumor treatment option.

Light and endogenous enzyme triggered plasmonic antennas for accurate subcellular molecular imaging with enhanced spatial resolution.

Developing accurate tumor-specific molecular imaging approaches holds great potential for evaluating cancer progression. However, traditional molecular imaging approaches still suffer from restricted tumor specificity due to the "off-tumor" signal leakage. In this work, we proposed light and endogenous APE1-triggered plasmonic antennas for accurate tumor-specific subcellular molecular imaging with enhanced spatial resolution. Light activation ensures subcellular molecular imaging and endogenous enzyme activation ensures tumor-specific molecular imaging. In addition, combined with the introduction of plasmon enhanced fluorescence (PEF), off-tumor signal leakage at the subcellular level was effectively reduced, resulting in the significantly enhanced discrimination ratio of tumor/normal cells (∼11.57-fold) which is better than in previous reports, demonstrating great prospects of these plasmonic antennas triggered by light and endogenous enzymes for tumor-specific molecular imaging at the subcellular level.

Photothermal synergistic nitric oxide controlled release injectable self-healing adhesive hydrogel for biofilm eradication and wound healing.

The development of injectable self-healing adhesive hydrogel dressings with excellent bactericidal activity and wound healing ability is urgently in demand for combating biofilm infections. Herein, a multifunctional hydrogel (QP/QT-MB) with near-infrared (NIR) light-activated mild photothermal/gaseous antimicrobial activity was developed based on the dynamic reversible borate bonds and hydrogen bonds crosslinking between quaternization chitosan (QCS) derivatives alternatively containing phenylboronic acid and catechol-like moieties in conjunction with the in situ encapsulation of BNN6-loaded mesoporous polydopamine (MPDA@BNN6 NPs). Given the dynamic reversible cross-linking feature, the versatile hybrid hydrogel exhibited injectability, flexibility, and rapid self-healing ability. The numerous phenylboronic acid and catechol-like moieties on the QCS backbone confer the hydrogel with specific bacterial affinity, desirable tissue adhesion, and antioxidant stress ability that enhance bactericidal activity and facilitate the regeneration of infection wounds. Under NIR irradiation, the QP/QT-MB hydrogels exhibited a desirable mild photothermal effect and NIR-activity controllable NO delivery, combined with the endogenous contact antimicrobial activity of hydrogel, contributing jointly to induce dispersal of biofilms and disruption of the bacterial plasma membranes, ultimately leading to bacteria inactivation and biofilm elimination. In vivo experiments demonstrated that the fabricated QP/QT-MB hydrogel platform was capable of inducing efficient eradication of the S. aureus biofilm in a severely infected wound model and accelerating infected wound repair by promoting collagen deposition, angiogenesis, and suppressing inflammatory responses. Additionally, the QP/QT-MB hydrogel demonstrated excellent biocompatibility in vitro and in vivo. Collectively, the hydrogel (QP/QT-MB) reveals great potential application prospects as a promising alternative in the field of biofilm-associated infection treatment.

Omega-3 Fatty Acid Therapy: A Review of Study Design Flaws, Quality, and Composition

There is marked heterogeneity in the clinical response to omega-3 fatty acid therapy with many authors documenting futility in large-scale trials, secondary re-analysis, and meta-analysis. The question of failure in the context of omega-3 therapy is multifactorial and complicated by the observation that fish intake has been broadly linked to significant risk reductions across a range of conditions. The question that remains is how can we resolve the discrepancy between pre-clinical evidence and epidemiology, which dually emphasize the benefit of omega-3 therapy against the limited success of large-scale clinical trials and smaller scale clinical studies that do not consistently report benefit and may even report harm, especially as it pertains to atrial fibrillation. We present three primary considerations that may clarify the supposed failures of omega-3 therapy: 1) correction for omega-3:omega-6 ratio and competition, 2) variation in the fatty acid composition and quality of omega-3 products, and 3) fundamental concerns pertaining to the omega-3 vehicle and its impact on omega-3 metabolism. While the predominant source of omega-3 therapy is supplements, they are typically not regulated prior to market like drugs and have significant variability in fatty acid composition, vehicle, oxidation, and quality control. Further, the individual response to omega-3 therapy is likely variable and dependent on ambient dietary conditions and inherited differences in endogenous desaturase activity, which has infrequently been accounted for in large studies. The net effect of these concerns should engender pharmaceutical and consumer companies alike to consider 1) refining trial design and 2) consider the role of oxidation in the failure of omega-3 products.

Integration of Endogenous Opioid System Research in the Interprofessional Diagnosis and Treatment of Obesity and Eating Disorders.

This third and final chapter in our trilogy introduces the clinical distinctions and phenotypical similarities between obesity and eating disorders. Research elaborating on the shared neurobiological substrates for obesity and eating disorders is discussed. We present an interprofessional model of treatment for both disordered eating and for obesity. Additionally, this chapter establishes the translational importance of research connecting endogenous opioid activity with both obesity and eating disorders, with an emphasis on clinical interventions. We conclude with a discussion of future directions for research.

Schisandra chinensis in Liver Disease: Exploring the Mechanisms and Therapeutic Promise of an Ancient Chinese Botanical

Background: Schisandra chinensis is a traditional Chinese herbal medicine that has been used for centuries for liver health. The active lignans in Schisandra, including schisandrin and gomisins, have exhibited anti-inflammatory, antioxidant, and hepatoprotective properties in preliminary studies. With rising rates of chronic liver diseases globally, there is interest in the potential therapeutic role of Schisandra. Purpose: To comprehensively review the current evidence for Schisandra chinensis in treating liver injury and disease and synthesize implications for future human research. Main body: Schisandra extracts decreased inflammatory cytokines and oxidative stress markers and increased endogenous antioxidant activity in animal models, suggesting utility in mitigating liver inflammation and damage. Additional preclinical studies demonstrated attenuated liver enzyme levels, necrosis, and fibrosis progression in chemical-induced hepatotoxicity with Schisandra treatment. Enhanced cytochrome P450 activity, glutathione production, and glycogen synthesis were also observed, improving detoxification and regeneration capacity. Small human trials in hepatitis and nonalcoholic fatty liver disease showed improved liver enzymes and symptoms with Schisandra supplementation but were limited in quality and sample size. Conclusion: Schisandra chinensis has biologically relevant mechanisms that warrant further human research on its role as a hepatoprotective phytotherapy. Well-designed, large-scale clinical trials are needed to establish efficacy and safety for liver disease applications.

Mesenchymal Stem Cell Engineering.

Mesenchymal stem cells (MSC) are multipotent stem cells that display the capacity to generate the tissue in which they reside. MSC have been used as progenitor cells to engineer cartilage implants that can be used to repair chondral and osteochondral lesions, or as trophic producers of bioactive factors to initiate endogenous regenerative activities in the arthritic joint. Targeted gene therapy might further enhance the capacity of MSC for chondrogenesis. By using a clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins genomic manipulation technique, target gene-modified MSC would be a promising therapeutic option for regeneration of diseased joints in the treatment of RA.

Uncovering the roles of sirtuin activity and food availability during the onset of the heat shock response in the California mussel (Mytilus californianus): Implications for antioxidative stress responses.

Sirtuins are a class of NAD+-dependent deacylases, with known regulatory roles in energy metabolism and cellular stress responses in vertebrates. Previous work using marine mussels have suggested a similar role in invertebrates, providing a potential mechanism linking food availability and thermal sensitivity in Mytilids. Sirtuin inhibitors affect mussels' recovery from environmental stressors, including acute heat shock and well-fed mussels exposed to sirtuin inhibitors and/or acute heat shock respond differently than poorly fed mussels, at the protein and whole-organism levels. While this implies a relationship between sirtuins, food availability, and temperature, the direct effects of sirtuin inhibitors (nicotinamide and suramin) on sirtuin activity or their putative effectors have not been explicitly tested. In this study, adult Mytilus californianus were acclimated to a low or high food availability and exposed to one of the following treatments: control, acute heat shock, sirtuin inhibitors, or acute heat shock and sirtuin inhibitors. Mussels increased sirtuin activity during early recovery (5h) from sirtuin inhibition and acute heat shock, but only if acclimated to a high food availability. Redox balance was also impacted in mussels acclimated to high food availability and exposed to sirtuin inhibitors, signifying interactions between ration, acute heat shock, and sirtuin inhibitors. Additionally, we found a correlation between sirtuin and superoxide dismutase activities, suggesting a potential regulatory role of oxidative stress by sirtuins. Following prolonged recovery (17h), we found increased sirtuin activity in mussels acclimated to low food availability, indicating that endogenous sirtuin activity may be related to food availability in mussels.

Pain, Fear, Anxiety, and Stress: Relations to the Endogenous Opioid System.

Pain, fear, stress, and anxiety are separate yet interrelated phenomena. Each of these concepts has an extensive individual body of research, with some more recent work focusing on points of conceptual overlap. The role of the endogenous opioid system in each of these phenomena is only beginning to be examined and understood. Research examining the ways in which endogenous opioids (e.g., beta-endorphin; βE) may mediate the relations among pain, fear, stress, and anxiety is even more nascent. This chapter explores the extant evidence for endogenous opioid activity as an underpinning mechanism of these related constructs, with an emphasis on research examining βE.

Antioxidant interaction between α-tocopherol and γ-oryzanol in HepG2 cells.

Minor constituents exhibit certain antioxidant interactions in vitro, and the effects in different media are different. However, it is not clear whether there are antioxidant interactions in cells after digestion and absorption. We utilized the cellular antioxidant evaluation model in HepG2 cells to study the antioxidant interaction between α-tocopherol and γ-oryzanol, and the interaction mechanism of a binary mixture was also illustrated. A cellular antioxidant assay (CAA) model and a combined index (CI) method were firstly used to explore the antioxidant activity and interaction of the binary mixture in HepG2 cells. The CAA value was positively correlated with the single addition concentration, while the results displayed a biphasic tendency with increasing concentrations of the binary mixture. The combination of TO11 (1 μg mL-1 α-tocopherol and 10 μg mL-1 γ-oryzanol) showed the greatest antioxidant activity and synergistic effect, and the maximum CAA value reached up to 94.84 ± 4.2. Then the mechanism of the synergistic antioxidant effect of the binary mixture was explained from three aspects including cellular uptake, intracellular reactive oxygen species (ROS) level and endogenous enzyme activity. The results demonstrated that the antioxidant interaction of the binary mixture in cells was related to cellular uptake of minor constituents, and the combination of TO11 exerted a synergistic effect by scavenging ROS and up-regulating glutathione peroxidase (GSH-Px) activity, resulting in the strongest cellular antioxidant activity. This study throws light on the nature of antioxidant interaction between minor constituents, which may contribute to the development of related functional foods and rational dietary collocation.

Endogenous Opioid Activity as the Mechanism of Action for Mitragyna speciosa (Kratom): The Current State of the Evidence.

Kratom (Mitragyna speciosa) is a substance derived from botanical compounds native to Southeast Asia. This substance has been cultivated predominantly in Thailand, Malaysia, Vietnam, and Myanmar, where it has historically been used in traditional medicine as a near panacea for several health problems. Such ritualistic use of kratom has been present for centuries; however, recreational use appears to have increased globally, especially in the United States. Pharmacodynamic and pharmacokinetic studies have found that kratom demonstrates a unique parabolic, dose-dependent pattern of effects ranging from stimulation to opioid and analgesic effects. Pharmacological research indicates that kratom is both a mu opioid receptor (μ-OR; MOR) and a kappa opioid receptor (κ-OR; KOR) agonist, which mediates its analgesic effects. Other research suggests that kratom may simultaneously act on dopaminergic and serotonergic receptors, which mediate its stimulant effects. This chapter reviews the literature related to the structural, functional, and cultural characteristics of kratom use. We begin with an overview of current and historical patterns of kratom, followed by a review of data on the pharmacodynamics and pharmacokinetics of kratom thus far.

Molecular Approaches to Measure Bacterial Extracellular Vesicles in Tissue Samples.

Extracellular vesicles (EVs) are naturally occurring lipid-bound nanoparticles produced by all cell types. Growing work demonstrates the ability of EVs to facilitate long-distance and cross-kingdom communication. Their innate barrier crossing and cell targeting properties make them a uniquely useful starting ground for novel drug delivery platforms. To better understand the endogenous activity and therapeutic potential of EVs, recent work has measured particle circulation and distribution in vivo using several approaches. Here, we describe molecular-based methods for quantifying bacterial EV distribution in collected tissue samples for biodistribution studies. These methods are important for understanding cell-cell communication facilitated by bacterial EVs and for identifying opportunities for using bacterial EVs as a therapeutic platform.

Circadian Genes and Economic Traits in Livestock Animals

Circadian rhythms are oscillators of endogenous autonomic activity in all living organisms and regulate economic traits such as reproduction, milk characteristics and growth performance in farm animals. These rhythms are directly or indirectly controlled by the circadian clock in a 24-hour cycle. It has evolved as an adaptive system for living organisms in a cyclical natural environment. A regular circadian rhythm can be associated with good health, well-being, strong immunity, and high economic characteristics. The interaction between circadian rhythmicity and the physiology of farm animals is becoming an important focus of animal science. Understanding the circadian genes (CLOCK, BMAL, PER1, PER2, CRY1, CRY2) and actions regulating circadian oscillation in farm animals is important to improve management and increase economic traits. The study aimed to summarise the research on the effects of circadian rhythm genes on productivity and to highlight the importance of this topic

Mechanisms of Action of Flavonoids: Antioxidant, Antibacterial and Antifungal Properties

Flavonoids, a diverse group of natural polyphenolic compounds found in various sources like fruits and vegetables, have garnered attention for their diverse biological activities, including antioxidant, antibacterial, and antifungal properties. This comprehensive review delves into the mechanisms through which flavonoids combat oxidative stress and hinder the growth of bacteria and fungi. In terms of antioxidative action, flavonoids showcase their efficacy by neutralizing reactive oxygen species through hydrogen atom and electron donation, augmenting endogenous antioxidant enzyme activity, and chelating transition metal ions. Their antibacterial effects target both Gram-positive and Gram-negative bacteria, disrupting cell membranes, inhibiting key enzymatic processes, and suppressing efflux pumps, collectively impeding bacterial growth, and causing cell death. Additionally, flavonoids exhibit antifungal properties by interfering with fungal cell membrane integrity, disrupting ergosterol biosynthesis, and modulating critical signal transduction pathways, ultimately hindering fungal growth and pathogenicity. This nuanced understanding of flavonoid mechanisms not only holds promise for therapeutic development but also inspires future advancements in pharmacological research.

Exogenous Melatonin Promotes Glucoraphanin Biosynthesis by Mediating Glutathione in Hairy Roots of Broccoli (Brassica oleracea L. var. italica Planch).

To investigate the mechanism of melatonin (MT)-mediated glutathione (GSH) in promoting glucoraphanin (GRA) and sulforaphane (SF) synthesis, the gene expression pattern and protein content of hairy broccoli roots under MT treatment were analyzed by a combination of RNA-seq and tandem mass spectrometry tagging (TMT) techniques in this study. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that both proteins and mRNAs with the same expression trend were enriched in the "Glutathione metabolism (ko00480)" and "Proteasome (ko03050)" pathways, and most of the differentially expressed genes (DEGs) and differentially abundant proteins (DAPs) regulating the two pathways were downregulated. The results showed that endogenous GSH concentration and GR activity were increased in hairy roots after MT treatment. Exogenous GSH could promote the biosynthesis of GRA and SF, and both exogenous MT and GSH could upregulate the expression of the GSTF11 gene related to the sulfur transport gene, thus promoting the biosynthesis of GRA. Taken together, this study provides a new perspective to explore the complex molecular mechanisms of improving GRA and SF synthesis levels by MT and GSH regulation.