A bioactive ligand-conjugated iridium(III) metal-based complex as a Keap1-Nrf2 protein-protein interaction inhibitor against acetaminophen-induced acute liver injury

OGG1: An emerging multifunctional therapeutic target for the treatment of diseases caused by oxidative DNA damage

Oxidative DNA damage-related diseases, such as incurable inflammation, malignant tumors, and age-related disorders, present significant challenges in modern medicine due to their complex molecular mechanisms and limitations in identifying effective treatment targets. Recently, 8-oxoguanine DNA glycosylase 1 (OGG1) has emerged as a promising multifunctional therapeutic target for the treatment of these challenging diseases. In this review, we systematically summarize the multiple functions and mechanisms of OGG1, including pro-inflammatory, tumorigenic, and aging regulatory mechanisms. We also highlight the potential of OGG1 inhibitors and activators as potent therapeutic agents for the aforementioned life-limiting diseases. We conclude that OGG1 serves as a multifunctional hub; the inhibition of OGG1 may provide a novel approach for preventing and treating inflammation and cancer, and the activation of OGG1 could be a strategy for preventing age-related disorders. Furthermore, we provide an extensive overview of successful applications of OGG1 regulation in treating inflammatory, cancerous, and aging-related diseases. Finally, we discuss the current challenges and future directions of OGG1 as an emerging multifunctional therapeutic marker for the aforementioned challenging diseases. The aim of this review is to provide a robust reference for scientific researchers and clinical drug developers in the development of novel clinical targeted drugs for life-limiting diseases, especially for incurable inflammation, malignant tumors, and age-related disorders.

Testicular toxicity in cisplatin-treated Wistar rats is mitigated by Daflon and associated with modulation of Nrf2/HO-1 and TLR4/NF-kB signaling

BACKGROUND

Testicular toxicity is a complication of cisplatin therapy and it limits its use. Since cisplatin-induced testicular damage is mediated by inflammation and oxidative stress, evaluation of the protective role of antioxidant and anti-inflammatory molecules such as micronized purified flavonoid fraction (Daflon®) is pertinent.

AIM

Therefore, this study investigated the mitigating effect of daflon against cisplatin-induced testicular toxicity. Also, the impact of daflon on Nrf2/HO-1 and TLR4/NF-kB pathways, which are key pathways in cisplatin toxicity, was explored.

MATERIALS AND METHODS

After 2 weeks of acclimatization, 20 male albino Wistar rats were allotted at random into 4 equal groups; control, daflon-treated, cisplatin-treated, and cisplatin+daflon-treated.

RESULTS

Daflon significantly restored cisplatin-induced reductions in body weight (112.20±9.01 vs. 129.60±5.68, P= 0.0175), body weight gain (-39.80±9.52 vs. -16.80±16.53, P= 0.0154), and testicular weight (1.69±0.08 vs. 1.95±0.13, P= 0.0980) and alterations in testicular histology. In addition, daflon abrogated cisplatin-induced rise in testicular CK (55.53±2.77 vs. 37.40±3.29, P< 0.0001) and LDH (74.52±3.20 vs. 65.89±2.08, P= 0.0009) activities, and lactate content (180.50±4.19 vs. 166.20±2.78, P< 0.0001). Also, daflon alleviated cisplatin-induced suppression of GnRH (5.09±0.60 vs. 10.17±0.51, P< 0.0001), LH (1.33±0.07 vs. 2.77±0.13, P< 0.0001), FSH (0.51±0.10 vs. 1.82±0.09, P< 0.0001), and testosterone (2.39±0.11 vs. 4.70±0.33, P< 0.001) as well as lowered sperm quality. More so, daflon attenuated cisplatin-induced testicular oxidative stress, inflammation, and apoptosis evidenced by daflon-driven suppression of MDA (14.16±0.66 vs. 9.22±0.52, P< 0.0001), TNF-α (79.42±5.66 vs. 54.13±3.56, P< 0.0001), IL-1β (8.63±0.41 vs. 3.37±0.43, P< 0.0001), IL-6 (6.87±0.48 vs. 3.67±0.32, P< 0.0001), and caspase 3 activity (4.20±0.26 vs. 0.72±0.23, P< 0.0001) and DNA fragmentation (34.60±3.05 vs. 17.20±3.19, P< 0.0001), and upregulation of GSH level (0.07±0.03 vs. 0.36±0.03, P< 0.0001), and GPx (5.96±0.46 vs. 11.88±1.05, P< 0.0001), GST (5.16±0.71 vs. 11.50±0.81, P< 0.0001), SOD (1.29±0.15 vs. 2.81±0.29, P< 0.0001), and catalase activities (6.18±0.69 vs. 10.71±0.74, P< 0.0001). Furthermore, daflon upregulated testicular Nrf2 expression (40.25±2.65 vs. 66.62±4.01, P< 0.0001) and HO-1 (4.18±0.56 vs. 8.79±0.55, P< 0.0001) activity but downregulated TLR4 (11.63±0.89 vs. 7.23±0.43, P< 0.0001) and NF-kB levels (113.20±3.36 vs. 78.22±3.90, P< 0.0001) in cisplatin-treated rats.

CONCLUSION

Collectively, the ameliorative effect of daflon on cisplatin-induced testicular toxicity is associated with inhibition of oxidative stress and TLR4/NF-kB-mediated inflammatory pathways and activation of Nrf2/HO-1 signaling.

Encoding and display technologies for combinatorial libraries in drug discovery: The coming of age from biology to therapy

Drug discovery is a sophisticated process that incorporates scientific innovations and cutting-edge technologies. Compared to traditional bioactivity-based screening methods, encoding and display technologies for combinatorial libraries have recently advanced from proof-of-principle experiments to promising tools for pharmaceutical hit discovery due to their high screening efficiency, throughput, and resource minimization. This review systematically summarizes the development history, typology, and prospective applications of encoding and displayed technologies, including phage display, ribosomal display, mRNA display, yeast cell display, one-bead one-compound, DNA-encoded, peptide nucleic acid-encoded, and new peptide-encoded technologies, and examples of preclinical and clinical translation. We discuss the progress of novel targeted therapeutic agents, covering a spectrum from small-molecule inhibitors and nonpeptidic macrocycles to linear, monocyclic, and bicyclic peptides, in addition to antibodies. We also address the pending challenges and future prospects of drug discovery, including the size of screening libraries, advantages and disadvantages of the technology, clinical translational potential, and market space. This review is intended to establish a comprehensive high-throughput drug discovery strategy for scientific researchers and clinical drug developers.

Deciphering Acetaminophen-Induced Hepatotoxicity: The Crucial Role of Transcription Factors like Nuclear Factor Erythroid 2-Related Factor 2 as Genetic Determinants of Susceptibility to Drug-Induced Liver Injury

Acetaminophen (APAP) is the most commonly used over-the-counter medication throughout the world. At therapeutic doses, APAP has potent analgesic and antipyretic effects. The efficacy and safety of APAP are influenced by multifactorial processes dependent upon dosing, namely frequency and total dose. APAP poisoning by repeated ingestion of supratherapeutic doses, depletes glutathione stores in the liver and other organs capable of metabolic bioactivation, leading to hepatocellular death due to exhausted antioxidant defenses. Numerous genes, encompassing transcription factors and signaling pathways, have been identified as playing pivotal roles in APAP toxicity, with the liver being the primary organ studied due to its central role in APAP metabolism and injury. Nuclear factor erythroid 2-related factor 2 (NRF2) and its array of downstream responsive genes are crucial in counteracting APAP toxicity. NRF2, along with its negative regulator Kelch-like ECH-associated protein 1, plays a vital role in regulating intracellular redox homeostasis. This regulation is significant in modulating the oxidative stress, inflammation, and hepatocellular death induced by APAP. In this review, we provide an updated overview of the mechanisms through which NRF2 activation and signaling critically influence the threshold for developing APAP toxicity. We also describe how genetically modified rodent models for NRF2 and related genes have been pivotal in underscoring the significance of this antioxidant response pathway. While NRF2 is a primary focus, the article comprehensively explores other genetic factors involved in phase I and phase II metabolism of APAP, inflammation, oxidative stress, and related pathways that contribute to APAP toxicity, thereby providing a holistic understanding of the genetic landscape influencing susceptibility to this condition. SIGNIFICANCE STATEMENT: This review summarizes the genetic elements and signaling pathways underlying APAP-induced liver toxicity, focusing on the crucial protective role of the transcription factor NRF2. This review also delves into the genetic intricacies influencing APAP safety and potential liver harm. It also emphasizes the need for deeper insight into the molecular mechanisms of hepatotoxicity, especially the interplay of NRF2 with other pathways.

Med1 inhibits ferroptosis and alleviates liver injury in acute liver failure via Nrf2 activation

BACKGROUND

Extensive hepatocyte mortality and the absence of specific medical therapy significantly contribute to the unfavorable prognosis of acute liver failure (ALF). Ferroptosis is a crucial form of cell death involved in ALF. In this study, we aimed to determine the impact of Mediator complex subunit 1 (Med1) on ferroptosis and its potential hepatoprotective effects in ALF.

RESULTS

Med1 expression is diminished in the liver of lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced ALF mice, as well as in hepatocytes damaged by H2O2 or TNF-α/D-GalN in vitro. Med1 overexpression mitigates liver injury and decreases the mortality rate of ALF mice by ferroptosis inhibition. The mechanism by which Med1 inhibits erastin-induced ferroptosis in hepatocytes involves the upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant genes heme oxygenase-1 (HO-1), glutamate cysteine ligase catalytic (GCLC), and NAD(P)H quinone oxidoreductase 1 (NQO1). Furthermore, Med1 overexpression suppresses the transcription of proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the liver of mice with LPS/D-GalN-induced ALF.

CONCLUSION

Overall, our research findings indicate that Med1 suppresses ferroptosis and alleviates liver injury in LPS/D-GalN-induced ALF through the activation of Nrf2. These findings substantiate the therapeutic viability of targeting the Med1-Nrf2 axis as a means of treating individuals afflicted with ALF.

MYC Oncogene: A Druggable Target for Treating Cancers with Natural Products

Various diseases, including cancers, age-associated disorders, and acute liver failure, have been linked to the oncogene, MYC. Animal testing and clinical trials have shown that sustained tumor volume reduction can be achieved when MYC is inactivated, and different combinations of therapeutic agents including MYC inhibitors are currently being developed. In this review, we first provide a summary of the multiple biological functions of the MYC oncoprotein in cancer treatment, highlighting that the equilibrium points of the MYC/MAX, MIZ1/MYC/MAX, and MAD (MNT)/MAX complexes have further potential in cancer treatment that could be used to restrain MYC oncogene expression and its functions in tumorigenesis. We also discuss the multifunctional capacity of MYC in various cellular cancer processes, including its influences on immune response, metabolism, cell cycle, apoptosis, autophagy, pyroptosis, metastasis, angiogenesis, multidrug resistance, and intestinal flora. Moreover, we summarize the MYC therapy patent landscape and emphasize the potential of MYC as a druggable target, using herbal medicine modulators. Finally, we describe pending challenges and future perspectives in biomedical research, involving the development of therapeutic approaches to modulate MYC or its targeted genes. Patients with cancers driven by MYC signaling may benefit from therapies targeting these pathways, which could delay cancerous growth and recover antitumor immune responses.

Covalent inhibition of epidermal growth factor receptor using a long-lived iridium(III)-afatinib probe

The overexpression and overactivation of epidermal growth factor receptor (EGFR) are frequently observed in human cancers, including squamous cell carcinoma and adenocarcinoma. In this study, a covalent EGFR probe was developed by conjugating afatinib to an iridium(III) scaffold. Complex 1 showed enhanced luminescence in living epidermoid squamous carcinoma A431 cells compared to other cell lines, via engaging EGFR as confirmed via CETSA and knockdown experiments. Moreover, complex 1 inhibited downstream targets of EGFR in cellulo with repression persisting after removal of the complex, indicating an irreversible mode of inhibition. Finally, complex 1 showed potent antiproliferative activity against A431 cells with comparable potency to afatinib alone. To our knowledge, complex 1 is the first EGFR covalent inhibitor based on an iridium scaffold reported in the literature, with the potential to be further explored as a theranostic agent in the future.

A Biomimetic Multifunctional Nanoframework for Symptom Relief and Restorative Treatment of Acute Liver Failure

Acute liver failure (ALF) is a rare and serious condition characterized by major hepatocyte death and liver dysfunction. Owing to the limited therapeutic options, this disease generally has a poor prognosis and a high mortality rate. When ALF cannot be reversed by medications, liver transplantation is often needed. However, transplant rejection and the shortage of donor organs still remain major challenges. Most recently, stem cell therapy has emerged as a promising alternative for the treatment of liver diseases. However, the limited cell delivery routes and poor stability of live cell products have greatly hindered the feasibility and therapeutic efficacy of stem cell therapy. Inspired by the functions of mesenchymal stem cells (MSCs) primarily through the secretion of several factors, we developed an MSC-inspired biomimetic multifunctional nanoframework (MBN) that encapsulates the growth-promoting factors secreted by MSCs via combination with hydrophilic or hydrophobic drugs. The red blood cell (RBC) membrane was coated with the MBN to enhance its immunological tolerance and prolong its circulation time in blood. Importantly, the MBN can respond to the oxidative microenvironment, where it accumulates and degrades to release the payload. In this work, two biomimetic nanoparticles, namely, rhein-encapsulated MBN (RMBN) and N-acetylcysteine (NAC)-encapsulated MBN (NMBN), were designed and synthesized. In lipopolysaccharide (LPS)/d-galactosamine (D-GalN)-induced and acetaminophen (APAP)-induced ALF mouse models, RMBN and NMBN could effectively target liver lesions, relieve the acute symptoms of ALF, and promote liver cell regeneration by virtue of their strong antioxidative, anti-inflammatory, and regenerative activities. This study demonstrated the feasibility of the use of an MSC-inspired biomimetic nanoframework for treating ALF.

Half sandwich-type osmium, ruthenium, iridium and rhodium complexes with bidentate glycosyl heterocyclic ligands induce cytostasis in platinum-resistant ovarian cancer cells and bacteriostasis in Gram-positive multiresistant bacteria

The toxicity of and resistance to platinum complexes as cisplatin, oxaliplatin or carboplatin calls for the replacement of these therapeutic agents in clinical settings. We have previously identified a set of half sandwich-type osmium, ruthenium and iridium complexes with bidentate glycosyl heterocyclic ligands exerting specific cytostatic activity on cancer cells but not on non-transformed primary cells. The apolar nature of the complexes, conferred by large, apolar benzoyl protective groups on the hydroxyl groups of the carbohydrate moiety, was the main molecular feature to induce cytostasis. We exchanged the benzoyl protective groups to straight chain alkanoyl groups with varying length (3 to 7 carbon units) that increased the IC50 value as compared to the benzoyl-protected complexes and rendered the complexes toxic. These results suggest a need for aromatic groups in the molecule. The pyridine moiety of the bidentate ligand was exchanged for a quinoline group to enlarge the apolar surface of the molecule. This modification decreased the IC50 value of the complexes. The complexes containing [(η6-p-cymene)Ru(II)], [(η6-p-cymene)Os(II)] or [(η5-Cp*)Ir(III)] were biologically active unlike the complex containing [(η5-Cp*)Rh(III)]. The complexes with cytostatic activity were active on ovarian cancer (A2780, ID8), pancreatic adenocarcinoma (Capan2), sarcoma (Saos) and lymphoma cell lines (L428), but not on primary dermal fibroblasts and their activity was dependent on reactive oxygen species production. Importantly, these complexes were cytostatic on cisplatin-resistant A2780 ovarian cancer cells with similar IC50 values as on cisplatin-sensitive A2780 cells. In addition, the quinoline-containing Ru and Os complexes and the short chain alkanoyl-modified complexes (C3 and C4) proved to be bacteriostatic in multiresistant Gram-positive Enterococcus and Staphylococcus aureus isolates. Hereby, we identified a set of complexes with submicromolar to low micromolar inhibitory constants against a wide range of cancer cells, including platinum resistant cells and against multiresistant Gram-positive bacteria.

KEAP1-NRF2 protein-protein interaction inhibitors: Design, pharmacological properties and therapeutic potential

The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is considered the master regulator of the phase II antioxidant response. It controls a plethora of cytoprotective genes related to oxidative stress, inflammation, and protein homeostasis, among other processes. Activation of these pathways has been described in numerous pathologies including cancer, cardiovascular, respiratory, renal, digestive, metabolic, autoimmune, and neurodegenerative diseases. Considering the increasing interest of discovering novel NRF2 activators due to its clinical application, initial efforts were devoted to the development of electrophilic drugs able to induce NRF2 nuclear accumulation by targeting its natural repressor protein Kelch-like ECH-associated protein 1 (KEAP1) through covalent modifications on cysteine residues. However, off-target effects of these drugs prompted the development of an innovative strategy, the search of KEAP1-NRF2 protein-protein interaction (PPI) inhibitors. These innovative activators are proposed to target NRF2 in a more selective way, leading to potentially improved drugs with the application for a variety of diseases that are currently under investigation. In this review, we summarize known KEAP1-NRF2 PPI inhibitors to date and the bases of their design highlighting the most important features of their respective interactions. We also discuss the preclinical pharmacological properties described for the most promising compounds.

Dehydroeburicoic Acid, a Dual Inhibitor against Oxidative Stress in Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a complicated disease which can lead to hepatocellular carcinoma; however, there is a lack of satisfactory therapeutics. Dehydroeburicoic acid (DEA) (1), a triterpenoid isolated from Antrodia cinnamomea, has been reported to act against ALD, but its mechanisms of action are still not clear. In this study, we report for the first time the use of DEA (1) as a dual inhibitor of the Keap1-Nrf2 protein-protein interaction (PPI) and GSK3β in an in vitro ALD cell model. DEA (1) engages Keap1 to disrupt the Keap1-Nrf2 PPI and inhibits GSK3β to restore Nrf2 activity in a Keap1-independent fashion. DEA (1) promotes Nrf2 nuclear translocation to activate downstream antioxidant genes. Importantly, DEA (1) restores the mitochondrial dysfunction induced by ethanol and generates antioxidant activity in the ALD cell model with minimal toxicity. We anticipate that DEA (1) could be a potential scaffold for the further development of clinical agents for treating ALD.

Multistage-Responsive Gene Editing to Sensitize Ion-Interference Enhanced Carbon Monoxide Gas Therapy

As a promising therapeutic modality targeting cancer, gas therapy still faces critical challenges, especially in enhancing therapeutic efficacy and avoiding gas poisoning risks. Here, a pH/glutathione (GSH) dual stimuli-responsive CRISPR/Cas9 gene-editing nanoplatform combined with calcium-enhanced CO gas therapy for precise anticancer therapy, is established. In the tumor microenvironment (TME), the fast biodegradation of the CaCO₃ layer via pH-induced hydrolyzation allows glucose oxidase (GOx) to catalyze glucose for H₂ O₂ production, which further reacts with manganese carbonyl (MnCO) and achieves the precise release of CO gas. Simultaneously, in situ Ca²⁺ overload from CaCO₃ degradation disturbs mitochondrial Ca²⁺ homeostasis, resulting in Ca²⁺ -driven reactive oxygen species (ROS) formation and subsequent mitochondrial apoptosis signaling pathway activation. Subsequently, by GSH-induced cleavage of a disulfide bond, the released Cas9/sgRNA (RNP) can achieve nuclear factor E2-related factor 2 (Nrf2) gene ablation to sensitize gas therapy by interfering with ROS signaling. This therapeutic modality endows codelivery of CRISPR, ions, and gas with smart control features, which demonstrates great potential for future clinical applications in precise nanomedicine.

Inhibition of fucosylation by 2-fluorofucose attenuated acetaminophen-induced liver injury via its anti-inflammation and anti-oxidative stress effects

Fucosylation is a common glycan terminal modification, which has been reported to be inhibited by 2-fluorofucose (2FF) both in vivo and in vitro. The present study aimed to investigate the effect of 2FF on acetaminophen (APAP)-induced acute liver injury, and further clarified the possible mechanisms. In the present study, inhibition of fucosylation by 2FF relieved APAP-induced acute liver injury in vivo. Pretreatment with 2FF remarkably suppressed APAP-induced oxidative stress and mitochondria damage. 2FF markedly enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and simultaneously promoted the expression of downstream proteins including HO-1 and NQO1. Furthermore, pretreatment with 2FF significantly suppressed the expression of inflammation-associated proteins, such as COX2 and iNOS. The data from lectin blot assay revealed that the alteration of α1,6-fucosylation was involved in APAP-induced acute liver injury. The second part of this study further confirmed that the enhancements to antioxidant capacity of 2FF pretreatment and α1,6-fucose deficiency were related to Nrf2/keap1 and NF-κB signaling pathways in HepG2 cells. Taken together, the current study suggested that 2FF might have a potential therapeutic effect for APAP-induced acute liver injury.

Sarmentosin promotes USP17 and regulates Nrf2-mediated mitophagy and cellular oxidative stress to alleviate APAP-induced acute liver failure

BACKGROUND

An overdose of acetaminophen (APAP), the main cause of acute liver failure (ALF), induces oxidative stress that ultimately causes mitochondrial impairment and hepatotoxicity. The nuclear factor erythroid 2-related factor 2 (Nrf2) was widely recognized as an anti-oxidative stress mechanism. The present study was aimed at investigating whether sarmentosin, extract from traditional Chinese medicine, protects the liver against APAP-induced injury via activating Nrf2 and subsequently decreasing oxidative stress.

METHODS

Male ICR mice were treated with sarmentosin oral administration for 1 week and injected APAP (300 mg/kg. i.p.) for acute liver injury model. The liver and serum of mice for histological and biochemistry analysis. AML12 and LO2 cells were used in vitro assays.

RESULTS

We found that sarmentosin moderately increased accumulation of Nrf2 via upregulating USP17-mediated ubiquitin inhibition at the early stage of hepatocytes damage. The Nrf2 separating from bonding protein Keap1 translocated into nucleus and activated downstream gene of antioxidants. Mitophagy, a unique autophagy can remove Reactive Oxygen Species (ROS) damaged mitochondria, was elevated in this progress to maintain mitochondria function and ROS homeostasis.

CONCLUSION

In summary, our research revealed that sarmentosin could alleviate APAP-induced liver acute injury through USP17-mediated Nrf2 overexpression and PINK1-dependent mitophagy.

Exploring the Therapeutic Effects of Black Ginseng on Non-alcoholic Fatty Liver Disease by Using Network Pharmacology and Molecular Docking

This study aimed to investigate the therapeutic effect of BG on non-alcoholic fatty liver disease (NAFLD) using network pharmacology combined with the molecular docking strategy. The saponin composition of BG was analyzed by liquid chromatography-mass spectrometry (LC-MS) instrument. Then the network pharmacology was applied to explore the potential targets and related mechanisms of BG in the treatment of NAFLD. After screening out key targets, molecular docking was used to predict the binding modes between ginsenoside and target. Finally, a methionine and choline deficiency (MCD) diet-induced NAFLD mice model was established to further confirm the therapeutic effect of BG on NAFLD. Twenty-four ginsenosides were annotated based on the MS and tandem MS information. Ten proteins were screened out as key targets closely related to BG treatment of NAFLD. The molecular docking showed that most of the ginsenosides had good binding affinities with ALT1. The validation experiment revealed that BG administration could reduce serum ALT, and AST levels and improve the MCD diet-induced histological changes in liver tissue. Moreover, BG could upregulate the phosphorylation level of AKT in the liver of NAFLD mice, thereby exerting the therapeutic effect on NAFLD. Further studies on the active ginsenosides as well as their synergistic action on NAFLD will be required to reveal the underlying mechanisms in-depth. This study demonstrates that network pharmacological prediction in conjunction with molecular docking is a viable technique for screening the active chemicals and related targets of BG that can be applied to other herbal medicines.

Homocysteine-targeting compounds as a new treatment strategy for diabetic wounds via inhibition of the histone methyltransferase SET7/9

In hypoxia and hyperglycemia, SET7/9 plays an important role in controlling HIF-1α methylation and regulating the transcription of HIF-1α target genes, which are responsible for angiogenesis and wound healing. Here, we report the Ir(III) complex Set7_1a bearing acetonitrile (ACN) ligands as a SET7/9 methyltransferase inhibitor and HIF-1α stabilizer. Interestingly, Set7_1a could engage SET7/9 and strongly inhibit SET7/9 activity, especially after preincubation with homocysteine (Hcy), which is elevated in diabetes. We hypothesize that Set7_1a exchanges ACN subunits for Hcy to disrupt the interaction between SET7/9 and SAM/SAH, which are structurally related to Hcy. Inhibition of SET7/9 methyltransferase activity by Set7_1a led to reduced HIF-1α methylation at the lysine 32 residue, causing increased HIF-1α level and recruitment of HIF-1α target genes that promote angiogenesis, such as VEGF, GLUT1, and EPO, in hypoxia and hyperglycemia. Significantly, Set7_1a improved wound healing in a type 2 diabetic mouse model by activating HIF-1α signaling and downstream proangiogenic factors. To our knowledge, this is the first Hcy-targeting iridium compound shown to be a SET7/9 antagonist that can accelerate diabetic wound healing. More importantly, this study opens a therapeutic avenue for the treatment of diabetic wounds by the inhibition of SET7/9 lysine methyltransferase activity.

Animal trials have demonstrated the potential of a new drug strategy to heal the wounds associated with diabetes, especially in the feet,which often lead to chronic damage, sometimes treatable only by amputation. Leung CH and Lin L at the University of Macau, China, and Ma DL at the Hong Kong Baptist University tested the new therapy on a mouse model of type 2 diabetes. The treatment uses a homocysteine-targeting metal complex that inhibits a key enzyme SET7/9 involved in the processes that cause diabetic wounds. The treatment activated a molecular signalling cascade involved in generating the new blood vessels needed for wounds to heal. It could help address the urgent need for better treatments for this serious problem.

Interference Reduction Biosensing Strategy for Highly Sensitive microRNA Detection

MicroRNAs are potential biomarkers for human cancers and other diseases due to their roles as post-transcriptional regulators for gene expression. However, the detection of miRNAs by conventional methods such as RT-qPCR, in situ hybridization, northern blot-based platforms, and next-generation sequencing is complicated by short length, low abundance, high sequence homology, and susceptibility to degradation of miRNAs. In this study, we developed a nicking endonuclease-mediated interference reduction rolling circle amplification (NEM-IR-RCA) strategy for the ultrasensitive and highly specific detection of miRNA-21. This method exploits the advantages of the optical properties of long-lived iridium(III) probes, in conjunction with time-resolved emission spectroscopy (TRES) and exponential rolling circle amplification (E-RCA). Under the NEM-IR-RCA-based signal enhancement processes, the limit of detection of miRNA-21 was down to 0.0095 fM with a linear range from 0.05 to 100 fM, which is comparable with the conventional RT-qPCR. Unlike RT-qPCR, the strategy was performed at a lower and constant temperature without heating/cooling cycles and reverse transcription. The strategy could clearly discriminate between matched and mismatched targets, demonstrating high specificity. Moreover, the potential application of this method was demonstrated in cancer cells and mouse serum samples, showing good agreement with RT-qPCR results. Apart from miRNA-21 detection, this platform could be also adapted for detecting other miRNAs, such as let-7a and miRNA-22, indicating its excellent potential for biomedical research and clinical diagnostics.

Immune-responsive gene 1 protects against liver injury caused by concanavalin A via the activation Nrf2/HO-1 pathway and inhibition of ROS activation pathways

Itaconate is produced by an enzyme encoded by the immune-responsive gene 1 (IRG1) and exerts antibacterial, anti-inflammatory, and antioxidant effects via multiple mechanisms. However, the role of IRG1/itaconate in liver injury caused by Concanavalin A (Con A) is not fully understood. In this study, we explored the therapeutic effect of IRG1/four-octyl itaconate (4-OI), a derivative of itaconate, on liver injury caused by Con A and its possible underlying mechanisms. In vivo experiments, we found that Con A promoted IRG1 expression in the liver tissue. Deletion of IRG1 in mice aggravated Con A-induced liver injury. Compared to wild-type (WT) mice, the inflammatory response, hepatocyte apoptosis, and serum cytokine levels were significantly increased, while the antioxidant capacity was significantly attenuated in IRG1^-/- mice. In addition, we found that Con A promoted the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome, caspase-1, and gasdermin D activation, and pyroptosis was more obvious in IRG1^-/- mice, while 4-OI inhibited pyroptosis. In vivo experiments showed that Con A promoted hepatocyte apoptosis by promoting reactive oxygen species (ROS) expression, and 4-OI reduced ROS-mediate apoptosis in NCTC 1469 cells. In RAW264.7 cells, we demonstrated that 4-OI inhibited the inflammatory response by promoting the nuclear factor erythroid 2 [NF-E2]-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway and inhibiting the nuclear factor-kappa B (NF-κB)/mitogen-activated protein kinases signaling pathway. To further confirm that Nrf2 is the target of itaconate, we pretreated WT mice with ML385, an Nrf2 inhibitor, and found that ML385 could weaken the protection of 4-OI in Con A-induced liver injury mouse model. Furthermore, when we knocked down the Nrf2 gene in NCTC 1469 and RAW264.7 cells, the effect of 4-OI in inhibiting inflammation and apoptosis also decreased. In conclusion, our study shows the importance of IRG1 in inflammation and oxidative stress, and suggests that it plays a vital protective role in Con A-induced liver injury. These findings indicate IRG1/itaconate is a potential therapeutic strategy for immune liver injury, which requires further clinical exploration.

A rapid and label-free DNA-based interference reduction nucleic acid amplification strategy for viral RNA detection

Common reference methods for COVID-19 diagnosis include thermal cycling amplification (e.g. RT-PCR) and isothermal amplification methods (e.g. LAMP and RPA). However, they may not be suitable for direct detection in environmental and biological samples due to background signal interference. Here, we report a rapid and label-free interference reduction nucleic acid amplification strategy (IR-NAAS) that exploits the advantages of luminescent iridium(III) probes, time-resolved emission spectroscopy (TRES) and multi-branch rolling circle amplification (mbRCA). Using IR-NAAS, we established a luminescence approach for diagnosing COVID-19 RNAs sequences RdRp, ORF1ab and N with a linear range of 0.06-6.0 × 10⁵ copies/mL and a detection limit of down to 7.3 × 10⁴ copies/mL. Moreover, the developed method was successfully applied to detect COVID-19 RNA sequences from various environmental and biological samples, such as domestic sewage, and mice urine, blood, feces, lung tissue, throat and nasal secretions. Apart from COVID-19 diagnosis, IR-NAAS was also demonstrated for detecting other RNA viruses, such as H1N1 and CVA10, indicating that this approach has great potential approach for routine preliminary viral detection.

Reactive Oxygen Species Production Is Responsible for Antineoplastic Activity of Osmium, Ruthenium, Iridium and Rhodium Half-Sandwich Type Complexes with Bidentate Glycosyl Heterocyclic Ligands in Various Cancer Cell Models

Platinum complexes are used in chemotherapy, primarily as antineoplastic agents. In this study, we assessed the cytotoxic and cytostatic properties of a set of osmium(II), ruthenium(II), iridium(III) and rhodium(III) half-sandwich-type complexes with bidentate monosaccharide ligands. We identified 5 compounds with moderate to negligible acute cytotoxicity but with potent long-term cytostatic activity. These structure-activity relationship studies revealed that: (1) osmium(II) p-cymene complexes were active in all models, while rhodium(III) and iridium(III) Cp* complexes proved largely inactive; (2) the biological effect was influenced by the nature of the central azole ring of the ligands—1,2,3-triazole was the most effective, followed by 1,3,4-oxadiazole, while the isomeric 1,2,4-oxadiazole abolished the cytostatic activity; (3) we found a correlation between the hydrophobic character of the complexes and their cytostatic activity: compounds with O-benzoyl protective groups on the carbohydrate moiety were active, compared to O-deprotected ones. The best compound, an osmium(II) complex, had an IC₅₀ value of 0.70 µM. Furthermore, the steepness of the inhibitory curve of the active complexes suggested cooperative binding; cooperative molecules were better inhibitors than non-cooperative ones. The cytostatic activity of the active complexes was abolished by a lipid-soluble antioxidant, vitamin E, suggesting that oxidative stress plays a major role in the biological activity of the complexes. The complexes were active on ovarian cancer, pancreatic adenocarcinoma, osteosarcoma and Hodgkin’s lymphoma cells, but were inactive on primary, non-transformed human fibroblasts, indicating their applicability as potential anticancer agents.

Theoretical investigation of electronic structures, second-order NLO responses of cyclometalated Ir(iii) and Rh(iii) counterpart complexes: effect of metal centers

Tuning center metal is an effective manner to modulate second-order NLO responses. When the big size Ir is introduced in complexes, the superior NLO responses can be found over its Rh counterparts.