Density Functional Studies of Coenzyme NADPH and Its Oxidized Form NADP+ : Structures, UV-Vis Spectra, and the Oxidation Mechanism of NADPH

Disulfidptosis, A Novel Cell Death Pathway: Molecular Landscape and Therapeutic Implications

Programmed cell death is pivotal for several physiological processes, including immune defense. Further, it has been implicated in the pathogenesis of developmental disorders and the onset of numerous diseases. Multiple modes of programmed cell death, including apoptosis, pyroptosis, necroptosis, and ferroptosis, have been identified, each with their own unique characteristics and biological implications. In February 2023, Liu Xiaoguang and his team discovered "disulfidptosis," a novel pathway of programmed cell death. Their findings demonstrated that disulfidptosis is triggered in glucose-starved cells exhibiting high expression of a protein called SLC7A11. Furthermore, disulfidptosis is marked by a drastic imbalance in the NADPH/NADP+ ratio and the abnormal accumulation of disulfides like cystine. These changes ultimately lead to the destabilization of the F-actin network, causing cell death. Given that high SLC7A11 expression is a key feature of certain cancers, these findings indicate that disulfidptosis could serve as the basis of innovative anti-cancer therapies. Hence, this review delves into the discovery of disulfidptosis, its underlying molecular mechanisms and metabolic regulation, and its prospective applications in disease treatment.

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

G6PDH as a key immunometabolic and redox trigger in arthropods

The enzyme glucose-6-phosphate dehydrogenase (G6PDH) plays crucial roles in glucose homeostasis and the pentose phosphate pathway (PPP), being also involved in redox metabolism. The PPP is an important metabolic pathway that produces ribose and nicotinamide adenine dinucleotide phosphate (NADPH), which are essential for several physiologic and biochemical processes, such as the synthesis of fatty acids and nucleic acids. As a rate-limiting step in PPP, G6PDH is a highly conserved enzyme and its deficiency can lead to severe consequences for the organism, in particular for cell growth. Insufficient G6PDH activity can lead to cell growth arrest, impaired embryonic development, as well as a reduction in insulin sensitivity, inflammation, diabetes, and hypertension. While research on G6PDH and PPP has historically focused on mammalian models, particularly human disorders, recent studies have shed light on the regulation of this enzyme in arthropods, where new functions were discovered. This review will discuss the role of arthropod G6PDH in regulating redox homeostasis and immunometabolism and explore potential avenues for further research on this enzyme in various metabolic adaptations.

The yeast transcription factor Stb5 acts as a negative regulator of autophagy by modulating cellular metabolism

Macroautophagy/autophagy is a highly conserved pathway of cellular degradation and recycling that maintains cell health during homeostatic conditions and facilitates survival during stress. Aberrant cellular autophagy contributes to the pathogenesis of human diseases such as cancer, neurodegeneration, and cardiovascular, metabolic and lysosomal storage disorders. Despite decades of research, there remain unanswered questions as to how autophagy modulates cellular metabolism, and, conversely, how cellular metabolism affects autophagy activity. Here, we have identified the yeast metabolic transcription factor Stb5 as a negative regulator of autophagy. Chromosomal deletion of STB5 in the yeast Saccharomyces cerevisiae enhances autophagy. Loss of Stb5 results in the upregulation of select autophagy-related (ATG) transcripts under nutrient-replete conditions; however, the Stb5-mediated impact on autophagy occurs primarily through its effect on genes involved in NADPH production and the pentose phosphate pathway. This work provides insight into the intersection of Stb5 as a transcription factor that regulates both cellular metabolic responses and autophagy activity.Abbreviations: bp, base pairs; ChIP, chromatin immunoprecipitation; G6PD, glucose-6-phosphate dehydrogenase; GFP, green fluorescent protein; IDR, intrinsically disordered region; NAD, nicotinamide adenine dinucleotide; NADP+, nicotinamide adenine dinucleotide phosphate; NADPH, nicotinamide adenine dinucleotide phosphate (reduced); ORF, open reading frame; PA, protein A; PCR, polymerase chain reaction; PE, phosphatidylethanolamine; PPP, pentose phosphate pathway; prApe1, precursor aminopeptidase I; ROS, reactive oxygen species; RT-qPCR, real-time quantitative PCR; SD, standard deviation; TF, transcription factor; TOR, target of rapamycin; WT, wild-type.

The Pho23-Rpd3 histone deacetylase complex regulates the yeast metabolic transcription factor Stb5

Macroautophagy/autophagy is an essential catabolic process for maintaining homeostasis and cell survival under stressful conditions. We previously characterized the metabolic transcription factor Stb5 as a negative modulator of autophagy through its regulation of genes involved in NADPH production. However, the molecular mechanisms regulating STB5 expression are not fully characterized. Here, we identify the yeast Pho23-Rpd3 histone deacetylase complex as a transcriptional regulator of STB5 . Our work provides insight into the mechanisms modulating the metabolic transcription factor Stb5 and expands on the repertoire of genes targeted by the Pho23-Rpd3 complex.

Multi-Omics Approach Reveals Redox Homeostasis Reprogramming in Early-Stage Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is a malignant tumor originating from proximal tubular epithelial cells, and despite extensive research efforts, its redox homeostasis characteristics and protein S-nitrosylation (or S-nitrosation) (SNO) modification remain largely undefined. This serves as a reminder that the aforementioned features demand a comprehensive inspection. We collected tumor samples and paracancerous normal samples from five patients with early-stage ccRCC (T1N0M0) for proteomic, SNO-proteome, and redox-targeted metabolic analyses. The localization and functional properties of SNO proteins in ccRCC tumors and paracancerous normal tissues were elucidated for the first time. Several highly useful ccRCC-associated SNO proteins were further identified. Metabolic reprogramming, redox homeostasis reprogramming, and tumorigenic alterations are the three major characteristics of early-stage ccRCC. Peroxidative damage caused by rapid proliferation coupled with an increased redox buffering capacity and the antioxidant pool is a major mode of redox homeostasis reprogramming. NADPH and NADP⁺, which were identified from redox species, are both effective biomarkers and promising therapeutic targets. According to our findings, SNO protein signatures and redox homeostasis reprogramming are valuable for understanding the pathogenesis of ccRCC and identifying novel topics that should be seriously considered for the diagnosis and precise therapy of ccRCC.

Quantification of the hydride donor abilities of NADH, NADPH, and BH3CN- in water

The nucleophilic reactivities of the hydride donors NADH, NADPH, and BH₃CN^- in water were quantified using kinetic measurements with benzhydrylium ions as reference electrophiles. All three hydride donors were found to possess almost identical nucleophilic reactivities, providing a potential explanation for why they are involved in similar transformations in biochemistry and organic synthesis, respectively.

An Energy Metabolism Study on the Efficacy of Naoxintong Capsules against Myocardial Infarction in a Rat Model

Background

In myocardial ischemia, optimizing the myocardial metabolic phenotype to improve cardiac function is critical. Naoxintong capsules (NXT) are widely prescribed in Chinese medicine for the treatment of cerebrovascular and cardiovascular diseases.

Methods

In this study, a rat model of myocardial infarction was established by ligation of the left anterior descending coronary artery. The structure and function of the heart were evaluated using echocardiography. The pathological changes of the rat myocardium and the myocardial volume collagen fraction (CVF) were examined using hematoxylin-eosin (HE) and Masson's trichrome staining (Masson). The expression of TNF-α and IL-6 were detected by immunohistochemistry. The level of cTnT was also measured to evaluate myocardial injury. In order to study the changes in energy metabolism in myocardial infarction and the effects of NXT, a targeted analysis method for detecting the 29 energy metabolites in cardiac muscle tissue was developed based on UPLC-QQQ-MS. Western blotting was used to detect the expression of proteins related to energy metabolism in myocardia.

Results

In the rat model of myocardial infarction, NXT showed obvious effects, such as improving heart function and increasing LVEF and LVFS. HE staining, Masson staining, and immunohistochemical results revealed that NXT decreased inflammatory infiltration, improved myocardial fibrosis, and reduced infarct size. In addition, NXT significantly reduced the level of serum cTnT. The levels of the 29 energy metabolites in cardiac muscle tissue were analyzed using a newly developed targeted analysis method. Compared to the sham group, the levels of 17 metabolites from different energy metabolic pathways, including four compounds in glycolysis metabolism, four compounds in TCA cycle, three compounds in oxidative phosphorylation, four compounds in purine metabolism, and two compounds in glutathione metabolism, displayed obvious changes induced by myocardial ischemia. Expressions of SIRT1, PGC-1α, and ATP5D proteins related to energy metabolism were decreased after myocardial infarction. These perturbations could all be reversed by NXT intervention, suggesting that the therapeutic effects of NXT were partially due to interferences with energy metabolisms.

Conclusion

This study provides a useful approach for investigating the mechanism of myocardial infarction and evaluating the efficacy of NXT from energy metabolism.

Mitochondrial dysfunction and oxidative stress contribute to cognitive and motor impairment in FOXP1 syndrome

FOXP1 haploinsufficiency underlies cognitive and motor impairments in individuals with FOXP1 syndrome. Here, we show that mice lacking one Foxp1 copy exhibit similar behavioral deficits, which may be caused by striatal dysfunction. Indeed, Foxp1^+/− striatal medium spiny neurons display reduced neurite branching, and we show altered mitochondrial biogenesis and dynamics; increased mitophagy; reduced mitochondrial membrane potential, structure, and motility; and elevated oxygen species in the striatum of these animals. As FOXP1 is highly conserved, our data strongly suggest that mitochondrial dysfunction and excessive oxidative stress contribute to the motor and cognitive impairments seen in individuals with FOXP1 syndrome. Thus, mitochondrial homeostasis is critical for normal development and can explain deficits in neurodevelopmental disorders.

FOXP1 syndrome caused by haploinsufficiency of the forkhead box protein P1 (FOXP1) gene is a neurodevelopmental disorder that manifests motor dysfunction, intellectual disability, autism, and language impairment. In this study, we used a Foxp1^+/− mouse model to address whether cognitive and motor deficits in FOXP1 syndrome are associated with mitochondrial dysfunction and oxidative stress. Here, we show that genes with a role in mitochondrial biogenesis and dynamics (e.g., Foxo1, Pgc-1α, Tfam, Opa1, and Drp1) were dysregulated in the striatum of Foxp1^+/− mice at different postnatal stages. Furthermore, these animals exhibit a reduced mitochondrial membrane potential and complex I activity, as well as decreased expression of the antioxidants superoxide dismutase 2 (Sod2) and glutathione (GSH), resulting in increased oxidative stress and lipid peroxidation. These features can explain the reduced neurite branching, learning and memory, endurance, and motor coordination that we observed in these animals. Taken together, we provide strong evidence of mitochondrial dysfunction in Foxp1^+/− mice, suggesting that insufficient energy supply and excessive oxidative stress underlie the cognitive and motor impairment in FOXP1 deficiency.

Plasma-Functionalized Isotactic Polypropylene Assembled with Conducting Polymers for Bacterial Quantification by NADH Sensing

Rapid detection of bacterial presence on implantable medical devices is essential to prevent biofilm formation, which consists of densely packed bacteria colonies able to withstand antibiotic-mediated killing. In this work, a smart approach is presented to integrate electrochemical sensors for detecting bacterial infections in biomedical implants made of isotactic polypropylene (i-PP) using chemical assembly. The electrochemical detection is based on the capacity of conducting polymers (CPs) to detect extracellular nicotinamide adenine dinucleotide (NADH) released from cellular respiration of bacteria, which allows distinguishing prokaryotic from eukaryotic cells. Oxygen plasma-functionalized free-standing i-PP, coated with a layer (≈1.1 µm in thickness) of CP nanoparticles obtained by oxidative polymerization, is used as working electrode for the anodic polymerization of a second CP layer (≈8.2 µm in thickness), which provides very high electrochemical activity and stability. The resulting layered material, i-PP_f /CP² , detects the electro-oxidation of NADH in physiological media with a sensitivity 417 µA cm^-2 and a detection limit up to 0.14 × 10^-3 m, which is below the concentration of extracellular NADH found for bacterial cultures of biofilm-positive and biofilm-negative strains.

Molecular level insights into the direct health impacts of some organic aerosol components

Quantum chemistry and biomodeling indicate that the studied organic aerosol components cannot directly cause oxidative stress or mutagenicity/carcinogenicity.

Two-Photon Excited Fluorescence Dynamics in NADH in Water-Methanol Solutions: The Role of Conformation States

The dynamics of polarized fluorescence in reduced nicotinamide adenine dinucleotide (NADH) at 460 nm under two-photon excitation at 720 nm by femtosecond laser pulses in water-methanol solutions has been studied experimentally and theoretically as a function of methanol concentration. A number of fluorescence parameters have been determined from experiment by means of the global fit procedure and then compared with the results reported by other authors. A comprehensive analysis of experimental errors was made. Ab initio calculations of the structure of NADH in water and methanol and of β-nicotinamide mononucleotide (NMNH) in vacuum have been carried out for clarifying the role of decay time heterogeneity. The main results obtained are as follows. An explanation of the heterogeneity in the measured fluorescence decay times in NADH has been suggested based on the influence of the internal molecular electric field in the nicotinamide ring on nonradiative decay rates. We suggest that different charge distributions in the cis and trans configurations result in different internal electrostatic field distributions that lead to the decay time heterogeneity. A slight but noticeable rise of the fluorescence decay times τ₁ and τ₂ with methanol concentration was observed and treated as a minor effect of a nonradiative relaxation slowing due to the decrease in solution polarity. Relative concentrations of the folded and unfolded NADH conformations in solutions have been determined using a new method of analysis of the rotational diffusion time τ_r as a function of methanol concentration on the basis of the Stokes-Einstein-Debye equation. The analysis of the fluorescence anisotropy parameters obtained under linearly and circularly polarized excitation and the parameter Ω has been carried out and resulted in the determination of the two-photon excitation tensor components and suggested the existence of two excitation channels with comparable intensities. These were the longitudinal excitation channel dominated by the diagonal tensor component S_zz and the mixed excitation channel dominated by the off-diagonal tensor components |S_xz² + S_yz²|^1/2.

NADPH homeostasis in cancer: functions, mechanisms and therapeutic implications

Nicotinamide adenine dinucleotide phosphate (NADPH) is an essential electron donor in all organisms, and provides the reducing power for anabolic reactions and redox balance. NADPH homeostasis is regulated by varied signaling pathways and several metabolic enzymes that undergo adaptive alteration in cancer cells. The metabolic reprogramming of NADPH renders cancer cells both highly dependent on this metabolic network for antioxidant capacity and more susceptible to oxidative stress. Modulating the unique NADPH homeostasis of cancer cells might be an effective strategy to eliminate these cells. In this review, we summarize the current existing literatures on NADPH homeostasis, including its biological functions, regulatory mechanisms and the corresponding therapeutic interventions in human cancers, providing insights into therapeutic implications of targeting NADPH metabolism and the associated mechanism for cancer therapy.