Mitochondriotropic antioxidant based on caffeic acid AntiOxCIN4 activates Nrf2-dependent antioxidant defenses and quality control mechanisms to antagonize oxidative stress-induced cell damage

Mitochondrial Dysfunction in Endothelial Progenitor Cells: Unraveling Insights from Vascular Endothelial Cells

Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.

Mitochondria dysfunction induced by decyl-TPP mitochondriotropic antioxidant based on caffeic acid AntiOxCIN6 sensitizes cisplatin lung anticancer therapy due to a remodeling of energy metabolism

The pharmacological interest in mitochondria is very relevant since these crucial organelles are involved in the pathogenesis of multiple diseases, such as cancer. In order to modulate cellular redox/oxidative balance and enhance mitochondrial function, numerous polyphenolic derivatives targeting mitochondria have been developed. Still, due to the drug resistance emergence in several cancer therapies, significant efforts are being made to develop drugs that combine the induction of mitochondrial metabolic reprogramming with the ability to generate reactive oxygen species, taking into consideration the varying metabolic profiles of different cell types. We previously developed a mitochondria-targeted antioxidant (AntiOxCIN6) by linking caffeic acid to lipophilic triphenylphosphonium cation through a 10-carbon aliphatic chain. The antioxidant activity of AntiOxCIN6 has been documented but how the mitochondriotropic compound impact energy metabolism of both normal and cancer cells remains unknown. We demonstrated that AntiOxCIN6 increased antioxidant defense system in HepG2 cells, although ROS clearance was ineffective. Consequently, AntiOxCIN6 significantly decreased mitochondrial function and morphology, culminating in a decreased capacity in complex I-driven ATP production without affecting cell viability. These alterations were accompanied by an increase in glycolytic fluxes. Additionally, we demonstrate that AntiOxCIN6 sensitized A549 adenocarcinoma cells for CIS-induced apoptotic cell death, while AntiOxCIN6 appears to cause metabolic changes or a redox pre-conditioning on lung MRC-5 fibroblasts, conferring protection against cisplatin. We propose that length and hydrophobicity of the C10-TPP+ alkyl linker play a significant role in inducing mitochondrial and cellular toxicity, while the presence of the antioxidant caffeic acid appears to be responsible for activating cytoprotective pathways.

Phytochemicals and quaternary phosphonium ionic liquids: Connecting the dots to develop a new class of antimicrobial agents

INTRODUCTION

The infections by multidrug-resistant bacteria are a growing threat to human health, and the efficacy of the available antibiotics is gradually decreasing. As such, new antibiotic classes are urgently needed.

OBJECTIVES

This study aims to evaluate the antimicrobial activity, safety and mechanism of action of phytochemical-based triphenylphosphonium (TPP+) conjugates.

METHODS

A library of phytochemical-based TPP+ conjugates was repositioned and extended, and its antimicrobial activity was evaluated against a panel of Gram-positive (methicillin-resistant Staphylococcus aureus - MRSA) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii) and fungi (Candida albicans, Cryptococcus neoformans var. grubii). The compounds' cytotoxicity and haemolytic profile were also evaluated. To unravel the mechanism of action of the best compounds, the alterations in the surface charge, bacterial membrane integrity, and cytoplasmic leakage were assessed.

RESULTS

Structure-activity-toxicity data revealed the contributions of the different structural components (phenolic ring, carbon-based spacers, carboxamide group, alkyl linker) to the compounds' bioactivity and safety. Dihydrocinnamic derivatives 5 m and 5n stood out as safe, potent and selective antibacterial agents against S. aureus (MIC < 0.25 µg/mL; CC50 > 32 µg/mL; HC10 > 32 µg/mL). Mechanistic studies suggest that the antibacterial activity of compounds 5 m and 5n may result from interactions with the bacterial cell wall and membrane.

CONCLUSIONS

Collectively, these studies demonstrate the potential of phytochemical-based TPP+ conjugates as a new class of antibiotics.

Chlorogenic acid as an indispensible partner of caffeic acid in coffee via selective regulation of prooxidative actions of caffeic acid

Chlorogenic acid (CGA) and caffeic acid (CA) are two major phenolic acids in coffee. Though the International Agency for Research on Cancer has classified CA as a Group2B carcinogen, coffee consumption seems generally safe within the usual levels of intake and is more likely to benefit health than to harm it. We thus speculated that CGA may effectively suppress the carcinogenic potential of CA. In a molar ratio achievable in vivo, this study shows that CGA can inhibit (i) copper reduction caused by CA, (ii) CA oxidation caused by copper, (iii) the formation of hydroxyl radicals by CA and copper, and (iv) DNA damage induced by CA, quercetin or (-)-epigallocatechin-3-gallate in the presence of copper. CA tends to undergo autoxidation to produce hydrogen peroxide and quinone, which further reacts with proteins to form quinoproteins. This autoxidation at a tolerable level normally induces beneficial adaptive responses. This study shows that CGA is less efficient than CA in producing hydrogen peroxide and quinoprotein; however, together they synergistically produce hydrogen peroxide and quinoprotein in vitro at a molar ratio achievable in vivo. In conclusion, CGA can selectively regulate the prooxidant activities of CA depending on whether copper is involved or not. CGA could be viewed as an indispensable partner of CA in coffee, given its dual role in suppressing the carcinogenic potential of CA and boosting CA autoxidation which is beneficial for disease prevention.

Brusatol induces ferroptosis in oesophageal squamous cell carcinoma by repressing GSH synthesis and increasing the labile iron pool via inhibition of the NRF2 pathway

Brusatol (Bru), a bioactive compound found in Brucea sumatrana, exerts antitumour effects on several malignancies. However, the role and molecular mechanism of Bru in squamous cell carcinoma of the oesophagus (ESCC) remain unclear. Here, we found that Bru decreased the survival of ESCC cells. Subsequently, the ferroptosis inhibitors, deferoxamine and liproxstatin-1, rescued Bru-induced cell death, indicating that ferroptosis plays a major role in Bru-induced cell death. Furthermore, Bru promoted lipid peroxidation, glutathione (GSH) depletion, and ferrous iron overload in vitro. Consistent with these in vitro results, Bru significantly inhibited tumour growth in KYSE150 xenograft nude mice by triggering ferroptosis. Mechanistically, nuclear factor E2-related factor 2 (NRF2) inactivation via increased ubiquitin-proteasome degradation was found to be a vital determinant of ferroptosis induced by Bru. Notably, Bru significantly decreases GSH synthesis, iron storage, and efflux by downregulating the expression of NRF2 target genes (glutamate-cysteine ligase catalytic subunit (GCLC), solute carrier family 7 member 11 (SLC7A11), ferritin heavy chain 1 (FTH1), and solute carrier family 40 member 1 (SLC40A1)), resulting in the accumulation of lethal lipid-based reactive oxygen species (ROS) and intracellular enrichment of chelated iron. Taken together, our findings indicate that ferroptosis is a novel mechanism underlying Bru-induced antitumour activity and will hopefully provide a valuable compound for ESCC treatment.

Nurturing through Nutrition: Exploring the Role of Antioxidants in Maternal Diet during Pregnancy to Mitigate Developmental Programming of Chronic Diseases

Chronic diseases represent one of the major causes of death worldwide. It has been suggested that pregnancy-related conditions, such as gestational diabetes mellitus (GDM), maternal obesity (MO), and intra-uterine growth restriction (IUGR) induce an adverse intrauterine environment, increasing the offspring's predisposition to chronic diseases later in life. Research has suggested that mitochondrial function and oxidative stress may play a role in the developmental programming of chronic diseases. Having this in mind, in this review, we include evidence that mitochondrial dysfunction and oxidative stress are mechanisms by which GDM, MO, and IUGR program the offspring to chronic diseases. In this specific context, we explore the promising advantages of maternal antioxidant supplementation using compounds such as resveratrol, curcumin, N-acetylcysteine (NAC), and Mitoquinone (MitoQ) in addressing the metabolic dysfunction and oxidative stress associated with GDM, MO, and IUGR in fetoplacental and offspring metabolic health. This approach holds potential to mitigate developmental programming-related risk of chronic diseases, serving as a probable intervention for disease prevention.

Tactics with Prebiotics for the Treatment of Metabolic Dysfunction-Associated Fatty Liver Disease via the Improvement of Mitophagy

Mitophagy/autophagy plays a protective role in various forms of liver damage, by renovating cellular metabolism linking to sustain liver homeostasis. A characterized pathway for mitophagy is the phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1)/Parkin-dependent signaling pathway. In particular, PINK1-mediated mitophagy could play an indispensable role in improving the metabolic dysfunction-associated fatty liver disease (MAFLD) which could precede to steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma. In addition, the PI3K/AKT/mTOR pathway might regulate the various characteristics of cellular homeostasis including energy metabolism, cell proliferation, and/or cell protection. Therefore, targeting mitophagy with the alteration of PI3K/AKT/mTOR or PINK1/Parkin-dependent signaling to eliminate impaired mitochondria might be an attractive strategy for the treatment of MAFLD. In particular, the efficacy of prebiotics for the treatment of MAFLD has been suggested to be useful via the modulation of the PI3K/AKT/mTOR/AMPK pathway. Additionally, several edible phytochemicals could activate mitophagy for the improvement of mitochondrial damages, which could also be a promising option to treat MAFLD with providing liver protection. Here, the potential therapeutics with several phytochemicals has been discussed for the treatment of MAFLD. Tactics with a viewpoint of prospective probiotics might contribute to the development of therapeutic interventions.

Health Benefits of Coffee Consumption for Cancer and Other Diseases and Mechanisms of Action

Coffee is one of the most widely consumed beverages worldwide, and epidemiology studies associate higher coffee consumption with decreased rates of mortality and decreased rates of neurological and metabolic diseases, including Parkinson's disease and type 2 diabetes. In addition, there is also evidence that higher coffee consumption is associated with lower rates of colon and rectal cancer, as well as breast, endometrial, and other cancers, although for some of these cancers, the results are conflicting. These studies reflect the chemopreventive effects of coffee; there is also evidence that coffee consumption may be therapeutic for some forms of breast and colon cancer, and this needs to be further investigated. The mechanisms associated with the chemopreventive or chemotherapeutic effects of over 1000 individual compounds in roasted coffee are complex and may vary with different diseases. Some of these mechanisms may be related to nuclear factor erythroid 2 (Nrf2)-regulated pathways that target oxidative stress or pathways that induce reactive oxygen species to kill diseased cells (primarily therapeutic). There is evidence for the involvement of receptors which include the aryl hydrocarbon receptor (AhR) and orphan nuclear receptor 4A1 (NR4A1), as well as contributions from epigenetic pathways and the gut microbiome. Further elucidation of the mechanisms will facilitate the potential future clinical applications of coffee extracts for treating cancer and other inflammatory diseases.

A Mitochondrion-Targeting Protein (B2) Primes ROS/Nrf2-Mediated Stress Signals, Triggering Apoptosis and Necroptosis in Lung Cancer

The betanodavirus B2 protein targets mitochondria and triggers mitochondrion-mediated cell death signaling in lung cancer cells; however, its molecular mechanism remains unknown. In this study, we observed that B2 triggers hydrogen peroxide/Nrf2-involved stress signals in the dynamic regulation of non-small lung cancer cell (NSCLC)-programmed cell death. Here, the B2 protein works as a necrotic inducer that triggers lung cancer death via p53 upregulation and RIP3 expression, suggesting a new perspective on lung cancer therapy. We employed the B2 protein to target A549 lung cancer cells and solid tumors in NOD/SCID mice. Tumors were collected and processed for the hematoxylin and eosin staining of tissue and cell sections, and their sera were used for blood biochemistry analysis. We observed that B2 killed an A549 cell-induced solid tumor in NOD/SCID mice; however, the mutant ΔB2 did not. In NOD/SCID mice, B2 (but not ΔB2) induced both p53/Bax-mediated apoptosis and RIPK3-mediated necroptosis. Finally, immunochemistry analysis showed hydrogen peroxide /p38/Nrf2 stress strongly inhibited the production of tumor markers CD133, Thy1, and napsin, which correlate with migration and invasion in cancer cells. This B2-triggered, ROS/Nrf2-mediated stress signal triggered multiple signals via pathways that killed A549 lung cancer tumor cells in vivo. Our results provide novel insight into lung cancer management and drug therapy.

Total coumarins of Pileostegia tomentella induces cell death in SCLC by reprogramming metabolic patterns, possibly through attenuating β-catenin/AMPK/SIRT1

BACKGROUND

Small-cell lung cancer (SCLC) is a high malignant and high energy-consuming type of lung cancer. Total coumarins of Pileostegia tomentella (TCPT) from a traditional folk medicine of Yao minority, is a potential anti-cancer mixture against SCLC, but the pharmacological and molecular mechanism of TCPT remains largely unknown.

METHODS

Screening of viability inhibition of TCPT among 7 cell lines were conducted by using CCK-8 assays. Anti-proliferative activities of TCPT in SCLC were observed by using colony formation and flow cytometry assays. Morphological changes were observed by transmission electron microscope and Mito-Tracker staining. High Throughput RNA-seq analysis and bio-informatics analysis were applied to find potential targeted biological and signaling pathways affected by TCPT. The mRNA expression of DEGs and protein expression of signalling proteins and metabolic enzymes were verified by qPCR and Western blot assays. Activity of rate-limiting enzymes and metabolite level were detected by corresponding enzyme activity and metabolites kits. Xenograft nude mice model of SCLC was established to observe the in vivo inhibition, metabolism reprogramming and mechanism of TCPT.

RESULTS

TCPT treatment shows the best inhibition in SCLC cell line H1688 rather than other 5 lung cancer cell lines. Ultrastructural investigation indicates TCPT induces mitochondria damage such as cytoplasm shrinkage, ridges concentration and early sight of autolysosome, as well as decrease of membrane potential. Results of RNA-seq combined bio-informatics analysis find out changes of metabolism progression affected the most by TCPT in SCLC cells, and these changes might be regulated by β-catenin/AMPK/SIRT1 axis. TCPT might mainly decline the activity and expression of rate-limiting enzymes, OGDH, PDHE1, and LDHA/B to reprogram aerobic oxidation pattern, resulting in reduction of ATP production in SCLC cells. Xenograft nude mice model demonstrates TCPT could induce cell death and inhibit growth in vivo. Assimilate to the results of in vitro model, TCPT reprograms metabolism by decreasing the activity and expression of rate-limiting enzymes (OGDH, PDHE1, and LDHA/B), and attenuates the expression of β-catenin, p-β-catenin, AMPK and SIRT1 accordance with in vitro data.

CONCLUSION

Our results demonstrated TCPT induces cell death of SCLC by reprograming metabolic patterns, possibly through attenuating master metabolic pathway axis β-catenin/AMPK/SIRT1.

Mitochondria-targeted anti-oxidant AntiOxCIN4 improved liver steatosis in Western diet-fed mice by preventing lipid accumulation due to upregulation of fatty acid oxidation, quality control mechanism and antioxidant defense systems

Non-alcoholic fatty liver disease (NAFLD) is a health concern affecting 24% of the population worldwide. Although the pathophysiologic mechanisms underlying disease are not fully clarified, mitochondrial dysfunction and oxidative stress are key players in disease progression. Consequently, efforts to develop more efficient pharmacologic strategies targeting mitochondria for NAFLD prevention/treatment are underway. The conjugation of caffeic acid anti-oxidant moiety with an alkyl linker and a triphenylphosphonium cation (TPP+), guided by structure-activity relationships, led to the development of a mitochondria-targeted anti-oxidant (AntiOxCIN4) with remarkable anti-oxidant properties. Recently, we described that AntiOxCIN4 improved mitochondrial function, upregulated anti-oxidant defense systems, and cellular quality control mechanisms (mitophagy/autophagy) via activation of the Nrf2/Keap1 pathway, preventing fatty acid-induced cell damage. Despite the data obtained, AntiOxCIN4 effects on cellular and mitochondrial energy metabolism in vivo were not studied. In the present work, we proposed that AntiOxCIN4 (2.5 mg/day/animal) may prevent non-alcoholic fatty liver (NAFL) phenotype development in a C57BL/6J mice fed with 30% high-fat, 30% high-sucrose diet for 16 weeks. HepG2 cells treated with AntiOxCIN4 (100 μM, 48 h) before the exposure to supraphysiologic free fatty acids (FFAs) (250 μM, 24 h) were used for complementary studies. AntiOxCIN4 decreased body (by 43%), liver weight (by 39%), and plasma hepatocyte damage markers in WD-fed mice. Hepatic-related parameters associated with a reduction of fat liver accumulation (by 600%) and the remodeling of fatty acyl chain composition compared with the WD-fed group were improved. Data from human HepG2 cells confirmed that a reduction of lipid droplets size and number can be a result from AntiOxCIN4-induced stimulation of fatty acid oxidation and mitochondrial OXPHOS remodeling. In WD-fed mice, AntiOxCIN4 also induced a hepatic metabolism remodeling by upregulating mitochondrial OXPHOS, anti-oxidant defense system and phospholipid membrane composition, which is mediated by the PGC-1α-SIRT3 axis. AntiOxCIN4 prevented lipid accumulation-driven autophagic flux impairment, by increasing lysosomal proteolytic capacity. AntiOxCIN4 improved NAFL phenotype of WD-fed mice, via three main mechanisms: a) increase mitochondrial function (fatty acid oxidation); b) stimulation anti-oxidant defense system (enzymatic and non-enzymatic) and; c) prevent the impairment in autophagy. Together, the findings support the potential use of AntiOxCIN4 in the prevention/treatment of NAFLD.

NRF2 and Mitochondrial Function in Cancer and Cancer Stem Cells

The NRF2–KEAP1 system is a fundamental component of the cellular response that controls a great variety of transcriptional targets that are mainly involved in the regulation of redox homeostasis and multiple cytoprotective mechanisms that confer adaptation to the stress conditions. The pleiotropic response orchestrated by NRF2 is particularly relevant in the context of oncogenic activation, wherein this transcription factor acts as a key driver of tumor progression and cancer cells’ resistance to treatment. For this reason, NRF2 has emerged as a promising therapeutic target in cancer cells, stimulating extensive research aimed at the identification of natural, as well as chemical, NRF2 inhibitors. Excitingly, the influence of NRF2 on cancer cells’ biology extends far beyond its mere antioxidant function and rather encompasses a functional crosstalk with the mitochondrial network that can influence crucial aspects of mitochondrial homeostasis, including biogenesis, oxidative phosphorylation, metabolic reprogramming, and mitophagy. In the present review, we summarize the current knowledge of the reciprocal interrelation between NRF2 and mitochondria, with a focus on malignant tumors and cancer stem cells.

GSK-J4, a Specific Histone Lysine Demethylase 6A Inhibitor, Ameliorates Lipotoxicity to Cardiomyocytes via Preserving H3K27 Methylation and Reducing Ferroptosis

Changes in modern lifestyle provoke a series of metabolic stresses such as hyperlipidemia. Excessive free fatty acids induce cardiomyocyte metabolic reprogramming and rearrangement of the lipid content of cardiomyocyte and promote oxidative stress. As a newly defined lipid peroxidation-related cell death pathway, the role of ferroptosis in metabolic stress-induced cardiomyocyte injury is poorly revealed. Our work indicates that GSK-J4, a histone lysine demethylase 6A/6B dual inhibitor, can alleviate palmitic acid (PA)-induced hypersensitivity to ferroptosis by suppressing H3K27 demethylation. Mechanistically, PA stimulation reduces the H3K27me3 level and hence promotes the expression of ACSL4, a key lipid modulator of ferroptosis. GSK-J4 pretreatment significantly preserves the H3K27me3 level and reduces the ACSL4 level. GSK-J4 also reduces reactive oxygen species to alleviate oxidative stress, which further decreases lipid peroxidation. Taken together, our data suggest that cardiomyocyte undergoes epigenetic reprogramming under metabolic challenges, rearranging lipid content, and sensitizing to ferroptosis. GSK-J4 can be a potential drug for treating hyperlipidemia-induced cardiomyocyte injury by targeting epigenetic modulations.