Targeted isolation, identification, and antioxidant evaluation of aromatic polyketides from a plant-derived fungus Ophiobolus cirsii LZU-1509.

There are >350 species of the Ophiobolus genus, which is not yet very well-known and lacks research reports on secondary metabolites. Three new 3,4-benzofuran polyketides 1-3, a new 3,4-benzofuran polyketide racemate 4, two new pairs of polyketide enantiomers (±)-5 and (±)-7, two new acetophenone derivatives 6 and 8, and three novel 1,4-dioxane aromatic polyketides 9-11, were isolated from a fungus Ophiobolus cirsii LZU-1509 derived from an important medicinal and economic crop Anaphalis lactea. The isolation was guided by LC-MS/MS-based GNPS molecular networking analysis. The planar structures and relative configurations were mainly elucidated by NMR and HR-ESI-MS data. Their absolute configurations were determined by using X-ray diffraction analysis and via comparing computational and experimental ECD, NMR, and specific optical rotation data. 9 possesses an unreported 5/6/6/6/5 five-ring framework with a 1,4-dioxane, and 10 and 11 feature unprecedented 6/6/6/5 and 6/6/5/6 four-ring frames containing a 1,4-dioxane. The biosynthetic pathways of 9-11 were proposed. 1-11 were nontoxic in HT-1080 and HepG2 tumor cells at a concentration of 20 µM, whereas 3 and 5 exerted higher antioxidant properties in the hydrogen peroxide-stimulated model in the neuron-like PC12 cells. They could be potential antioxidant agents for neuroprotection.

Glutathione-triggered prodrugs: Design strategies, potential applications, and perspectives.

The burgeoning prodrug strategy offers a promising avenue toward improving the efficacy and specificity of cytotoxic drugs. Elevated intracellular levels of glutathione (GSH) have been regarded as a hallmark of tumor cells and characteristic feature of the tumor microenvironment. Considering the pivotal involvement of elevated GSH in the tumorigenic process, a diverse repertoire of GSH-triggered prodrugs has been developed for cancer therapy, facilitating the attenuation of deleterious side effects associated with conventional chemotherapeutic agents and/or the attainment of more efficacious therapeutic outcomes. These prodrug formulations encompass a spectrum of architectures, spanning from small molecules to polymer-based and organic-inorganic nanomaterial constructs. Although the GSH-triggered prodrugs have been gaining increasing interests, a comprehensive review of the advancements made in the field is still lacking. To fill the existing lacuna, this review undertakes a retrospective analysis of noteworthy research endeavors, based on a categorization of these molecules by their diverse recognition units (i.e., disulfides, diselenides, Michael acceptors, and sulfonamides/sulfonates). This review also focuses on explaining the distinct benefits of employing various chemical architecture strategies in the design of these prodrug agents. Furthermore, we highlight the potential for synergistic functionality by incorporating multiple-targeting conjugates, theranostic entities, and combinational treatment modalities, all of which rely on the GSH-triggering. Overall, an extensive overview of the emerging field is presented in this review, highlighting the obstacles and opportunities that lie ahead. Our overarching goal is to furnish methodological guidance for the development of more efficacious GSH-triggered prodrugs in the future. By assessing the pros and cons of current GSH-triggered prodrugs, we expect that this review will be a handful reference for prodrug design, and would provide a guidance for improving the properties of prodrugs and discovering novel trigger scaffolds for constructing GSH-triggered prodrugs.

Association between magnesium, copper, and potassium intakes with risk of rheumatoid arthritis: a cross-sectional study from National Health and Nutrition Examination Survey (NHANES).

BACKGROUND: The relationship between Mg (magnesium), Cu (copper), and K (potassium) intakes and the risk of rheumatoid arthritis (RA) remains limited. The aim of present study was to examine the associations between Mg, Cu and K intakes with RA. METHODS: Using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2018, we examined the association between Mg, Cu and K intakes and the risk of RA among US adults. After adjustment for age, sex, race, BMI, educational level, smoking history, alcohol consumption, family Poverty Income Ratio (PIR), diabetes and total daily energy intake, logistic regression models and smooth curve fitting were applied to examine the associations of Mg, Cu and K intakes with RA. RESULTS: A total of 18,338 participants were included (1,008 participants with RA). The multivariate adjusted ORs (95% CI) of RA were [0.66 (0.51, 0.84)], [0.76 (0.60, 0.97)], and [0.75 (0.58, 0.97)] in the highest versus lowest quartile of magnesium intakes, respectively. A nonlinear association between Cu intakes and RA was found. When Cu intake (ln) was between 0.6-2.2 mg, the risk of RA reduced by 26% for every 1 mg increase of intake in Cu [0.74 (0.58, 0.96)]. CONCLUSIONS: Higher Mg, Cu and K intakes may be inversely associated with the risk of RA among US adults, and an inverse L-shaped association between dietary Cu and RA was found.

Imaging of Carbonic Anhydrase Level in Epilepsy with an Environment-Sensitive Fluorescent Probe.

Carbonic anhydrases (CAs) participate in various physiological and pathological activities by catalyzing the interconversion between carbon dioxide and bicarbonate ions. Under normal circumstances, they guarantee that the relevant biological reactions in our body occur within an appropriate time scale. Abnormal expression or activity alteration of CAs is closely related to the pathogenesis of diverse diseases. This work reports an inhibitor-directed fluorescent probe FMRs-CA for the detection of CAs. Excellent selectivity, favorable biocompatibility, and desirable blood-brain barrier (BBB) penetration endow the probe with the ability to image the fluctuation of CAs in cells and mice. We achieved in situ visualization of the increased CAs in hypoxic cells with this probe. Additionally, probe FMRs-CA was mainly enriched within the liver and gradually metabolized by the liver. With the help of FMRs-CA, the increase of CAs in epileptic mouse brains was revealed first from the perspective of imaging, providing the mechanism connection between abnormal CA expressions and epilepsy.

Aloe-emodin alleviates doxorubicin-induced cardiotoxicity via inhibition of ferroptosis.

Aloe-emodin (AE), a novel ferroptosis inhibitor, alleviates the doxorubicin (DOX)-induced cardiotoxicity in H9c2 rat cardiomyocytes. The inhibition of ferroptosis and the protective effect against cardiotoxicity were evaluated via MTT assay in H9c2 cells. The molecular mechanism of action (MOA) of nuclear factor erythroid 2-related factor 2 (Nrf2) activation, including transactivation of multiple downstream cytoprotective genes, were further assessed by Western blot, luciferase reporter assay and qRT-PCR analyses. Fluorescent imaging was performed to detect the change of intracellular reactive oxygen species, mitochondrial membrane potential and lipid peroxidation. In addition, an infrared spectroscopy was employed to detect the AE-Fe (II) complex. AE, alleviates oxidative stress in DOX-induced H9c2 cells by activating Nrf2 and increasing the expression of Nrf2 downstream antioxidant genes, SLC7A11 and GPX4. Furthermore, AE complexes bivalent iron and regulates the intracellular iron-related genes. In conclusion, the discovery of AE as a novel ferroptosis inhibitor and its MOA provides a new perspective for further exploration of cardio-protective agents in cancer patients during chemotherapy.

Simultaneous arthroscopic cystectomy and unicompartmental knee arthroplasty for the management of partial knee osteoarthritis with a popliteal cyst: A case report.

Introduction: Popliteal cysts are secondary to degenerative changes in the knee joint. After total knee arthroplasty (TKA), 56.7% of patients with popliteal cysts at 4.9 years follow-up remained symptomatic in the popliteal area. However, the result of simultaneous arthroscopic cystectomy and unicompartmental knee arthroplasty (UKA) was uncertain. Case presentation: A 57-year-old man was admitted to our hospital with severe pain and swelling in his left knee and the popliteal area. He was diagnosed with severe medial unicompartmental knee osteoarthritis (KOA) with a symptomatic popliteal cyst. Subsequently, arthroscopic cystectomy and unicompartmental knee arthroplasty (UKA) were performed simultaneously. A month after the operation, he returned to his normal life. There was no progression in the lateral compartment of the left knee and no recurrence of the popliteal cyst at the 1-year follow-up. Conclusion: For KOA patients with a popliteal cyst seeking UKA, simultaneous arthroscopic cystectomy and UKA are feasible with great success if managed appropriately.

Efficacy and Safety of the Chinese Herbal Compound TJAOA101 in Treating Diminished Ovarian Reserve: A Protocol for Multicenter, Prospective, and Pre-Post Study.

OBJECTIVE: Diminished ovarian reserve (DOR) can lead to early menopause, poor fecundity, and an increased risk of disorders such as osteoporosis, cardiovascular disease, and cognitive impairment, seriously affecting the physical and mental health of women. There is still no safe and effective strategy or method to combat DOR. We have developed a novel Chinese herbal formula, Tongji anti-ovarian aging 101 (TJAOA101), to treat DOR. However, its safety and efficacy need to be further validated. METHODS: In this prospective and pre-post clinical trial, 100 eligible patients aged 18-45 diagnosed with DOR will be recruited. All participants receive TJAOA101 twice a day for 3 months. Then, comparisons before and after treatment will be analyzed, and the outcomes, including anti-mullerian hormone (AMH) and follicle-stimulating hormone (FSH) levels and the antral follicle count (AFC), the recovery rate of menopause, and the Kupperman index (KMI), will be assessed at baseline, every month during medication (the intervention period), and 1, 3 months after medication (the follow-up period). Assessments for adverse events will be performed during the intervention and follow-up periods. CONCLUSION: A multicenter, prospective study will be conducted to further confirm the safety and efficacy of TJAOA101 in treating DOR and to provide new therapeutic strategies for improving the quality of life in DOR patients.

Puromycin Prodrug Activation by Thioredoxin Reductase Overcomes Its Promiscuous Cytotoxicity.

Overexpression of the selenoprotein thioredoxin reductase (TrxR) has been documented in malignant tissues and is of pathological significance for many types of tumors. The antibiotic puromycin (Puro) is a protein synthesis inhibitor causing premature polypeptide chain termination during translation. The well-defined action mechanism of Puro makes it a useful tool in biomedical studies. However, the nonselective cytotoxicity of Puro limits its therapeutic applications. We report herein the construction and evaluation of two Puro prodrugs, that is, S1-Puro with a five-membered cyclic disulfide trigger and S2-Puro with a linear disulfide trigger. S1-Puro is selectively activated by TrxR and shows the TrxR-dependent cytotoxicity to cancer cells, while S2-Puro is readily activated by thiols. Furthermore, S1-Puro displays higher stability in plasma than S2-Puro. We expect that this prodrug strategy may promote the further development of Puro as a therapeutic agent.

Hemin as a General Static Dark Quencher for Constructing Heme Oxygenase-1 Fluorescent Probes.

The development of small-molecule probes suitable for live-cell applications remains challenging yet highly desirable. We report the first fluorescent probe, RBH, for imaging the heme oxygenase-1 (HO-1) activity in live cells after discovering hemin as a universal dark quencher. Hemin works via a static quenching mechanism and shows high quenching efficiency (>97 %) with fluorophores across a broad spectrum (λex =400-700 nm). The favorable properties of RBH (e.g. long excitation/emission wavelengths, fast response rate and high magnitude of signal increase) enable its use for determining HO-1 activity in complex biological samples. As HO-1 is involved in regulating antioxidant defence, iron homeostasis and gasotransmitter carbon monoxide production, we expect RBH to be a powerful tool for dissecting its functions. Also, the discovery of hemin as a general static dark quencher provides a straightforward strategy for constructing novel fluorescent probes for diverse biological species.

The biological activities of quinolizidine alkaloids.

Quinolizidine alkaloids isolated from various marine and terrestrial animals and plants are primarily composed of lupinine-, matrine-, and sparteine-type alkaloids. Matrine, phenanthroquinolizidines, bis-quinolizidines, and small molecules from amphibian skins are representative compounds of such alkaloids. Quinolizidine alkaloids harbor anticancer, antibacterial, antiinflammatory, antifibrosis, antiviral, and anti-arrhythmia. In this chapter, we comprehensively outline the biological activity and pharmacological action of quinolizidine alkaloids and discuss new avenues toward the discovery of novel and more efficient drugs based on these naturally occurring compounds. It is urgent for basic research and clinical practice to conduct more targeted comprehensive research based on the lead drugs of quinolizidine alkaloids with significant pharmacological activity.

Naphthalimide Fluorescent Skeleton for Facile and Accurate Quantification of Glutathione.

Glutathione (GSH), the most prevalent nonprotein thiol in biological systems, acts as both an antioxidant to manipulate intracellular redox homeostasis and a nucleophile to detoxify xenobiotics. The fluctuation of GSH is closely related to the pathogenesis of diverse diseases. This work reports the construction of a nucleophilic aromatic substitution-type probe library based on the naphthalimide skeleton. After an initial evaluation, the compound R13 was identified as a highly efficient GSH fluorescent probe. Further studies demonstrate that R13 could readily quantify GSH in cells and tissues via a straightforward fluorometric assay with a comparable accuracy to the results from the HPLC. We then used R13 to quantify the content of GSH in mouse livers after X-ray irradiation, revealing that irradiation-induced oxidative stress leads to the increase of oxidized GSH (GSSG) and depletion of GSH. In addition, probe R13 was also applied to investigate the alteration of the GSH level in the Parkinson's mouse brains, showing a decrease of GSH and an increase of GSSG in Parkinson's mouse brains. The convenience of the probe in quantifying GSH in biological samples facilitates further understanding of the fluctuation of the GSH/GSSG ratio in diseases.

Synthesis and discovery of Baylis-Hillman adducts as potent and selective thioredoxin reductase inhibitors for cancer treatment.

The selenoprotein thioredoxin reductase (TrxR) is of paramount importance in maintaining cellular redox homeostasis, and aberrant upregulation of TrxR is frequently observed in various cancers due to their elevated oxidative stress in cells. Thus, it seems promising and feasible to target the ablation of intracellular TrxR for the treatment of cancers. We report herein the design and synthesis of a series of Baylis-Hillman adducts, and identified a typical adduct that possesses the superior cytotoxicity against HepG2 cells over other types of cancer cells. The biological investigation shows the selected typical adduct selectively targets TrxR in HepG2 cells, which thereafter results in the collapse of intracellular redox homeostasis. Further mechanistic studies reveal that the selected typical adduct arrests the cell cycle in G1/G0 phase. Importantly, the malignant metastasis of HepG2 cells is significantly restrained by the selected typical adduct. With well-defined molecular target and mechanism of action, the selected typical adduct, even other Baylis-Hillman skeleton-bearing compounds, merits further development as candidate or ancillary agent for the treatment of various cancers.

Isolation and Identification of Novel Antioxidant Polyketides from an Endophytic Fungus Ophiobolus cirsii LZU-1509.

Sixteen new polyketides, ophicirsins A-P (1-16), including four novel carbon skeletons (5-9, 14, 15, and 16), were isolated from the extract of an endophytic fungus Ophiobolus cirsii LZU-1509. The unique frameworks of ophicirsin N (14) and O (15) feature a different cyclic ether connected with an aromatic ring system. Ophicirsin P (16) is characterized by the unprecedented heterozygote of a polyketide and an alkaloid. The absolute stereochemistries of those polyketides were characterized via single-crystal X-ray diffraction analysis and the experimental and computational electric circular dichroism spectra comparison. Theoretical reaction pathways in the fermentation to generate different novel skeletons starting from acetyl CoA and malonyl CoA helped to assign their structures. Compounds 1-16 appear almost nontoxic in HepG2 and HT-1080 tumor cells. Their antioxidant effects were further evaluated, and 15 exhibits an excellent protection activity in hydrogen peroxide-stimulated oxidative damage in neuron-like PC12 cells via screening all compounds. Moreover, 15 displays a greater ability to scavenge the 2,2-diphenyl-1-picrylhydrazyl free radicals than resveratrol. Taken together, these findings suggest that the novel polyketides could serve as potential antioxidant agents for neuroprotection.

Mitochondria-targeted iridium-based photosensitizers enhancing photodynamic therapy effect by disturbing cellular redox balance.

Photodynamic therapy (PDT) is a non-invasive, light-activated treatment approach that has been broadly employed in cancer. Cyclometallic iridium (Ш) complexes are candidates for ideal photosensitizers due to their unique photophysical and photochemical features, such as high quantum yield, large Stokes shift, strong resistance to photobleaching, and high cellular permeability. We evaluated a panel of iridium complexes and identified PC9 as a powerful photosensitizer to kill cancer cells. PC9 shows an 8-fold increase of cytotoxicity to HeLa cells under light irradiation. Further investigation discloses that PC9 has a strong mitochondrial-targeting ability and can inhibit the antioxidant enzyme thioredoxin reductase, which contributes to improving PDT efficacy. Our data indicate that iridium complexes are efficient photosensitizers with distinct physicochemical properties and cellular actions, and deserve further development as promising agents for PDT.

Thioredoxin Signaling Pathways in Cancer.

Significance: Thioredoxin (Trx) is a powerful antioxidant that reduces protein disulfides to maintain redox stability in cells and is involved in regulating multiple redox-dependent signaling pathways. Recent Advance: The current accumulation of findings suggests that Trx participates in signaling pathways that interact with various proteins to manipulate their dynamic regulation of structure and function. These network pathways are critical for cancer pathogenesis and therapy. Promising clinical advances have been presented by most anticancer agents targeting such signaling pathways. Critical Issues: We herein link the signaling pathways regulated by the Trx system to potential cancer therapeutic opportunities, focusing on the coordination and strengths of the Trx signaling pathways in apoptosis, ferroptosis, immunomodulation, and drug resistance. We also provide a mechanistic network for the exploitation of therapeutic small molecules targeting the Trx signaling pathways. Future Directions: As research data accumulate, future complex networks of Trx-related signaling pathways will gain in detail. In-depth exploration and establishment of these signaling pathways, including Trx upstream and downstream regulatory proteins, will be critical to advancing novel cancer therapeutics. Antioxid. Redox Signal. 38, 403-424.

Alterperylenol as a Novel Thioredoxin Reductase Inhibitor Induces Liver Cancer Cell Apoptosis and Ferroptosis.

Natural products are a rich resource for discovering innovational drugs. Herein, we isolated and characterized two compounds dihydroalterperylenol (DAP) and alterperylenol (AP) from Alternaria sp. MG1, an endophytic fungus isolated from Vitis quinquangularis, and investigated the underlying antitumor mechanism of AP. Mechanistically, AP inhibits the growth of HepG2 cells by targeting the selenoprotein thioredoxin reductase (TrxR) and ultimately induces cell apoptosis and ferroptosis. Compared to DAP, the α,ß-unsaturated carbonyl structure of AP is an indispensable moiety for its antitumor activity and TrxR inhibition. Specifically, inhibition of TrxR causes the extensive reactive oxygen species and consequently results in DNA damage, G2/M cell cycle arrest, and mitochondrial fission. Furthermore, ferroptosis is driven via excess toxic lipid peroxidation and elevation of intracellular iron levels via regulating iron-related proteins. In vivo validation also shows that AP owns anticancer activity in xenograft mice. Collectively, our results disclose a novel natural TrxR inhibitor AP exerting the antitumor effect via inducing cell apoptosis and ferroptosis and evidence that AP is a promising candidate agent for liver carcinoma therapy. The link of TrxR inhibition to ferroptosis further highlights the physiological importance of TrxR in regulating ferroptosis.

MiR-30b-5p attenuates the inflammatory response and facilitates the functional recovery of spinal cord injury by targeting the NEFL/mTOR pathway.

BACKGROUND: Neurofilament light chain (NEFL) has been identified as a biomarker for spinal cord injury (SCI), but its effect and underlying mechanism in SCI remain unclear. METHODS: SCI rat models were established for in vivo studies. Lipopolysaccharide (LPS)-induced cell models were used for in vitro studies. The protein and mRNA expression levels of genes were evaluated by western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The pathological changes in rats after SCI were subjected to histological examinations. The interaction of NEFL and upstream miRNAs was explored using dual-luciferase reporter gene assays. RESULTS: NEFL was highly expressed in SCI rat spinal cord tissues and LPS-stimulated PC12 cells. NEFL silencing showed an inhibitory effect on the morphological changes of SCI rats and the secretion of inflammatory factors and facilitated functional recovery of SCI rats. MiR-30b-5p was demonstrated to target NEFL and negatively regulate NEFL mRNA and protein levels. Downregulation of miR-30b-5p in SCI cell and rat models was demonstrated. MiR-30b-5p alleviated the inflammatory response in SCI rat models and LPS-stimulated PC12 cells and promoted functional recovery in rats by targeting NEFL. NEFL activated mTOR signaling. MiR-30b-5p inactivated mTOR signaling by negatively regulating NEFL. CONCLUSION: MiR-30b-5p alleviated the inflammatory response and facilitated the functional recovery of SCI rats by targeting NEFL to inactivate the mTOR pathway.

Association between Serum Cotinine Levels and Bone Mineral Density: An Analysis of the National Health and Nutrition Examination Survey (NHANES).

Purpose: To investigate the relationship between serum cotinine and lumbar bone mineral density (BMD) among 7905 participants aged 30 years and over. Method: A total of 3945 men and 3960 women from the National Health and Nutrition Examination Survey 2011-2018 were included in this cross-sectional analysis. Independent variable was serum cotinine, which is a biomarker of cigarette exposure. The outcome variable was lumbar BMD. We investigated the associations of serum cotinine levels and lumbar BMD using multivariable linear regression models. Results: Serum cotinine concentration was negatively associated with lumbar BMD after adjustment of relevant covariables (ß = -0.039, 95% CI: -0.078 to -0.014, P = 0.005). However, in the subgroup analysis stratified by gender, this negative association remained only in women (ß = -0.072, 95% CI: -0.132 to -0.012, P = 0.019). Conclusion: Our study suggested that elevated serum cotinine level correlated with decreased lumbar BMD, especially in women. This finding indicated that reducing cigarette exposure and maintaining serum cotinine at a low level may be beneficial to bone health for adults.