Induction of apoptotic program in cell-free extracts: requirement for dATP and cytochrome c

Copper-instigated modulatory cell mortality mechanisms and progress in kidney diseases

Copper is a vital cofactor in various enzymes, plays a pivotal role in maintaining cell homeostasis. When copper metabolism is disordered and mitochondrial dysfunction is impaired, programmed cell death such as apoptosis, paraptosis, pyroptosis, ferroptosis, cuproptosis, autophagy and necroptosis can be induced. In this review, we focus on the metabolic mechanisms of copper. In addition, we discuss the mechanism by which copper induces various programmed cell deaths. Finally, this review examines copper's involvement in prevalent kidney diseases such as acute kidney injury and chronic kidney disease. The findings indicate that the use of copper chelators or plant extracts can mitigate kidney damage by reducing copper accumulation, offering novel insights into the pathogenesis and treatment strategies for kidney diseases.

Targeting kinases that regulate programmed cell death: a new therapeutic strategy for breast cancer

Breast cancer is one of the most prevalent malignant tumors among women and ranks as the second leading cause of cancer-related deaths in females, primarily due to delays in diagnosis and shortcomings in treatment strategies. Consequently, there is a pressing need to identify reliable therapeutic targets and strategies. In recent years, the identification of effective biomarkers-particularly novel molecular therapeutic targets-has become a focal point in breast cancer research, aimed at predicting disease aggressiveness and monitoring treatment responses. Simultaneously, advancements in understanding the molecular mechanisms underlying cellular programmed death have opened new avenues for targeting kinase-regulated programmed cell death as a viable therapeutic strategy. This review summarizes the latest research progress regarding kinase-regulated programmed death (including apoptosis, pyroptosis, autophagy, necroptosis, and ferroptosis) in breast cancer treatment. It covers the key kinases involved in this mechanism, their roles in the onset and progression of breast cancer, and strategies for modulating these kinases through pharmacological interventions.

Inhibition of PINK1 senses ROS signaling to facilitate neuroblastoma cell pyroptosis

Mitochondria serve as the primary source of intracellular reactive oxygen species (ROS), which play a critical role in orchestrating cell death pathways such as pyroptosis in various types of cancers. PINK1-mediated mitophagy effectively removes damaged mitochondria and reduces detrimental ROS levels, thereby promoting cell survival. However, the regulation of pyroptosis by PINK1 and ROS in neuroblastoma remains unclear. In this study, we demonstrate that inhibition or deficiency of PINK1 sensitizes ROS signaling and promotes pyroptosis in neuroblastoma cells via the BAX-caspase-GSDME signaling pathway. Specifically, inhibition of PINK1 by AC220 or knockout of PINK1 impairs mitophagy and enhances ROS production, leading to oxidation and oligomerization of TOMM20, followed by mitochondrial recruitment and activation of BAX. Activated BAX facilitates the release of CYCS (cytochrome c, somatic) from the mitochondria into the cytosol, activating CASP3 (caspase 3). Subsequently, activated CASP3 cleaves and activates GSDME, inducing pyroptosis. Furthermore, inhibition or deficiency of PINK1 potentiates the anti-tumor effects of the clinical ROS-inducing drug ethacrynic acid (EA) to inhibit neuroblastoma progression in vivo. Therefore, our study provides a promising intervention strategy for neuroblastoma through the induction of pyroptosis.Abbreviation: AC220, quizartinib; ANOVA, analysis of variance; ANXA5, annexin A5; BAX, BCL2 associated X, apoptosis regulator; BAK1, BCL2 antagonist/killer 1; CCCP, carbonyl cyanide m-chlorophenyl hydrazone; COX4/COX IV, cytochrome c oxidase subunit 4; CS, citrate synthase; CSC, cancer stem cell; CYCS, cytochrome c, somatic; DTT, dithiothreitol; DNA, deoxyribonucleic acid; EA, ethacrynic acid; Fer-1, ferroptosis inhibitor ferrostatin-1; FLT3, fms related tyrosine kinase 3; GSDMD, gasdermin D; GSDME, gasdermin E; kDa, kilodalton; LDH, lactate dehydrogenase; MFN1, mitofusin 1; MFN2, mitofusin 2; mito, mitochondria; mito-ROS, mitochondrial ROS; mtKeima, mitochondria-targeted monomeric keima-red; ml, microliter; MT-CO2, mitochondrially encoded cytochrome c oxidase II; NAC, antioxidant N-acetyl-L-cysteine; Nec-1, necroptosis inhibitor necrostatin-1; OMA1, OMA1 zinc metallopeptidase; OMM, outer mitochondrial membrane; PARP, poly(ADP-ribose) polymerase; PBS, phosphate-buffered saline; PI, propidium iodide; PINK1, PTEN induced kinase 1; PRKN/Parkin, parkin RBR E3 ubiquitin protein ligase; Q-VD, Q-VD-OPH; ROS, reactive oxygen species; sg, single guide; sh, short hairpin; STS, staurosporine; TOMM20, translocase of outer mitochondrial membrane 20; TIMM23, translocase of inner mitochondrial membrane 23; μm, micrometer; μM, micromolar.

Mitochondrial classic metabolism and its often-underappreciated facets

For many decades, mitochondria were essentially regarded as the main providers of the adenosine triphosphate (ATP) required to maintain the viability and function of eukaryotic cells, thus the widely popular metaphor "powerhouses of the cell". Besides ATP generation - via intermediary metabolism - these organelles have also traditionally been known, albeit to a lesser degree, for their notable role in biosynthesis, both as generators of biosynthetic intermediates and/or as the sites of biosynthesis. From the 1990s onwards, the concept of mitochondria as passive organelles providing the rest of the cell, from which they were otherwise isolated, with ATP and biomolecules on an on-demand basis has been challenged by a series of paradigm-shifting discoveries. Namely, it was shown that mitochondria act as signaling effectors to upregulate ATP generation in response to growth-promoting stimuli and that they are actively engaged, through signaling and epigenetics, in the regulation of a plethora of cellular processes, ultimately deciding cell function and fate. With the focus of mitochondrial research increasingly placed in these "non-classical" functions, the centrality of mitochondrial intermediary metabolism to biosynthesis and other mitochondrial functions tends to be overlooked. In this article, we revisit mitochondrial intermediary metabolism and illustrate how its intermediates, by-products and molecular machinery underpin other mitochondrial functions. A certain emphasis is given to frequently overlooked functions, namely the biosynthesis of iron‑sulfur (FeS) clusters, the only known function shared by all mitochondria and mitochondrion-related organelles. The generation of reactive oxygen species (ROS) and their putative role in signaling is also discussed in detail.

Cytosolic cytochrome c represses ferroptosis

The release of cytochrome c, somatic (CYCS) from mitochondria to the cytosol is an established trigger of caspase-dependent apoptosis. Here, we unveil an unexpected role for cytosolic CYCS in inhibiting ferroptosis-a form of oxidative cell death driven by uncontrolled lipid peroxidation. Mass spectrometry and site-directed mutagenesis revealed the existence of a cytosolic complex composed of inositol polyphosphate-4-phosphatase type I A (INPP4A) and CYCS. This CYCS-INPP4A complex is distinct from the CYCS-apoptotic peptidase activating factor 1 (APAF1)-caspase-9 apoptosome formed during mitochondrial apoptosis. CYCS boosts INPP4A activity, leading to increased formation of phosphatidylinositol-3-phosphate, which prevents phospholipid peroxidation and plasma membrane rupture, thus averting ferroptotic cell death. Unbiased screening led to the identification of the small-molecule compound 10A3, which disrupts the CYCS-INPP4A interaction. 10A3 sensitized cultured cells and tumors implanted in immunocompetent mice to ferroptosis. Collectively, these findings redefine our understanding of cytosolic CYCS complexes that govern diverse cell death pathways.

Mitochondria-targeted photothermal-chemodynamic therapy enhances checkpoint blockade immunotherapy on colon cancer

Immunotherapy has emerged as a hotspot for cancer treatment. However, the response rate of monotherapy remains relatively low in clinical settings. Photothermal therapy (PTT), which employs light energy to ablate tumors, can also activate tumor-specific immune responses. This effect has been attributed in several studies to the release of damage-associated molecular patterns (DAMPs) triggered by mitochondrial injury. We propose that mitochondria-targeted PTT may better synergize with immunotherapy. Herein, we constructed a multifunctional nanoplatform that enables mitochondria-targeted photothermal-chemodynamic combination therapy by conjugating indocyanine green-thiol (ICG-SH) and mercaptoethyl-triphenylphosphonium (TPP-SH) onto polyvinyl pyrrolidone (PVP)-coated gold-copper nanoparticles (AIT). Upon near-infrared light (NIR) irradiation, AIT ablates cancer cells and amplifies the effect of chemodynamic therapy (CDT), thereby inducing apoptosis in the tumor. The combination of CDT and PTT promotes immunogenic cell death, which could synergize with checkpoint blockade immunotherapy. In a bilateral mouse colon cancer model, we observed complete eradication of light-irradiated primary tumors and significant inhibition of distant untreated tumors in the group treated with AIT plus anti-PD-1 (αPD-1). We found a significant increase in serum levels of pro-inflammatory factors, including interleukin-6 (IL-6), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α), following PTT/CDT/immunotherapy treatment, suggesting effective activation of the immune response. The enhanced immunogenicity caused by AIT with αPD-1 treatment resulted in efficient antigen presentation, as indicated by the increased infiltration of dendritic cells (DCs) into the tumor-draining lymph nodes (LNs). We also observed enhanced infiltration of CD8+ T cells in distant tumors in the AIT with αPD-1 group compared to αPD-1 alone. Hence, mitochondria-targeting represents an effective strategy to potentiate the combination of photothermal, chemodynamic, and immune checkpoint blockade therapies for the treatment of metastatic cancer.

Non-coding RNA as a key regulator and novel target of apoptosis in diabetic cardiomyopathy: Current status and future prospects

The occurrence of diabetic cardiomyopathy (DCM) can be independent of several risk factors such as hypertension and myocardial ischemia, which can lead to heart failure, thus seriously threatening human health and life. Sustained hyperglycemic stimulation can induce cardiomyocyte apoptosis, which is recognized as the pathological basis of DCM. It has been demonstrated that dysregulation induced by apoptosis is closely associated to progression of DCM, but mechanisms behind it requires further clarification. Currently, increasing evidence has shown that non-coding RNA (ncRNA), especially microRNA, long-chain non-coding RNA (lncRNA), and circular RNA (circRNA), play a regulative role in apoptosis, thus affecting the progression of DCM. Notably, some ncRNAs have also exhibit potential significance as biomarkers and/or therapeutic targets for patients with DCM. In this review, recent findings regarding the potential mechanisms of ncRNA in regulating apoptosis and their role in the progression of DCM were systematically summarized in this research. The conclusion reveals that ncRNA abnormalities exert a crucial role in pathological changes of DCM, which offers potential therapeutic targets for the prevention of DCM.

A comprehensive survey of cytotoxic active half-sandwich Ir(III) complexes: structural perspective, and mechanism of action

Iridium(III) complexes, particularly those with piano-stool structures, have drawn a lot of interest recently as possible anticancer drugs. These complexes, which have displayed enhanced cytotoxicity and cytoselectivity compared with clinically approved drugs like cisplatin, oxaliplatin, and carboplatin, hold promising prospects for further anticancer research. Our review aims to explore the complex interplay between cytotoxic properties, cellular uptake efficiency, and intracellular distribution properties of this class of Ir(III) complexes, considering the variation of the coordination site atoms. We provide an overview of the majority of research on mono- and polynunclear half-sandwich Ir(III) complexes with mono- and bidentate ligands, focusing on the impact of altering the leaving group, tethers, substituents on the cyclopentadienyl ring and ligand, spacers, and counter ions on the cytotoxicity and mode of action.

Proteomic profiling uncovers sexual dimorphism in the muscle response to wheel running exercise in the FLExDUX4 murine model of facioscapulohumeral muscular dystrophy

FLExDUX4 is a murine experimental model of facioscapulohumeral muscular dystrophy (FSHD) characterized by chronic, low levels of leaky expression of the human full-length double homeobox 4 gene (DUX4-fl). FLExDUX4 mice exhibit mild pathologies and functional deficits similar to people affected by FSHD. Proteomic studies in FSHD could offer new insights into disease mechanisms underpinned by post-transcriptional processes. We used mass spectrometry-based proteomics to quantify the abundance of 1322 proteins in triceps brachii muscle, encompassing both male and female mice in control and free voluntary wheel running (VWR) in Wild-type (n=3) and FLExDUX4 (n=3) genotypes. We report the triceps brachii proteome of FLExDUX4 mice recapitulates key skeletal muscle clinical characteristics of human FSHD, including alterations to mitochondria, RNA metabolism, oxidative stress, and apoptosis. RNA-binding proteins exhibit a sex-specific difference in FLExDUX4 mice. Sexual dimorphism of mitochondrial protein adaptation to exercise was uncovered specifically in FLExDUX4 mice, where females increased, but males decreased mitochondrial proteins after a 6-week of VWR. Our results highlight the importance of identifying sex-specific diagnostic biomarkers to enable more reliable monitoring of FSHD therapeutic targets. Our data provides a resource for the FSHD research community to explore the burgeoning aspect of sexual dimorphism in FSHD.

In Brief

Nishimura et al. conducted proteomic analysis of triceps brachii muscle in the FLExDUX4 murine model of FSHD and verified FLExDUX4 mice recapitulate key skeletal muscle clinical characteristics of human FSHD, including disruptions to the mitochondrial proteome and proteins associated with RNA metabolism, oxidative stress, and apoptosis. RNA-binding proteins and the mitochondrial proteome response to exercise exhibited sexual dimorphism in FLExDUX4 mice. Specifically, females exhibited increases, whereas males exhibited decreases in mitochondrial protein abundance after 6-weeks voluntary wheel running.

Highlights

FLExDUX4 muscle proteome mirrors pathophysiology of FSHD patient myoblastsMitochondrial proteins are more abundant in FLExDUX4 as compared to WT miceSeverity of proteome disruption is greater in male than female miceRNA-binding proteins exhibit a sex-specific difference in FLExDUX4 miceSex-specific mitochondrial proteome response to VWR in FLExDUX4 mice.

Dl-3-n-butylphthalein inhibits neuronal apoptosis and ferroptosis after cerebral ischemia-reperfusion injury in rats by regulating CXCR4

OBJECTIVE

To investigate the anti-apoptosis and anti-ferroptosis effects of dl-3-n-butylphthalide (dl-NBP) on cerebral ischemia-reperfusion injury (CIRI) in rats, and the potential involvement of cysteine-X-cysteine chemokine receptor 4 (CXCR4).

METHODS

The differentially expressed genes between healthy people and stroke patients were screened by GEO database. A transient middle cerebral artery occlusion rat model was used to induce CIRI in vivo. Rats were randomly divided into sham group, tMCAO group, and dl-NBP + tMCAO group. The therapeutic effect of dl-NBP in vivo and its effect on apoptosis and ferroptosis in brain tissues were evaluated. An in vitro oxygen-glucose deprivation/reperfusion (OGD/R) model was established to simulate CIRI in cultured PC12 cells, and the effects of dl-NBP on apoptosis and ferroptosis were examined. In this model, CXCR4 expression was assessed by western blotting and its involvement in dl-NBP-mediated protection assessed by inhibition with AMD3100.

RESULTS

In the stroke-related GSE22255 and GSE66724 datasets, a total of six genes with increased co-expression were found, including CXCR4. Dl-NBP treatment significantly reduced both the volume of cerebral infarction and the degree of cerebral edema, and improved neurological function in rats. dl-NBP reduced the degree of apoptosis and ferroptosis and alleviated CIRI both in vivo and in vitro. The pro-survival effects of dl-NBP were significantly reversed after CXCR4 inhibition with AMD3100.

CONCLUSION

Dl-NBP has anti-apoptotic and anti-ferroptotic effects on CIRI both in vivo and in vitro, and this effect is mediated by CXCR4.

Less is better: various means to reduce protein load in the endoplasmic reticulum

The endoplasmic reticulum (ER) is an important organelle that controls the intracellular and extracellular environments. The ER is responsible for folding almost one-third of the total protein population in the eukaryotic cell. Disruption of ER-protein folding is associated with numerous human diseases, including metabolic disorders, neurodegenerative diseases, and cancer. During ER perturbations, the cells deploy various mechanisms to increase the ER-folding capacity and reduce ER-protein load by minimizing the number of substrates entering the ER to regain homeostasis. These mechanisms include signaling pathways, degradation mechanisms, and other processes that mediate the reflux of ER content to the cytosol. In this review, we will discuss the recent discoveries of five different ER quality control mechanisms, including the unfolded protein response (UPR), ER-associated-degradation (ERAD), pre-emptive quality control, ER-phagy and ER to cytosol signaling (ERCYS). We will discuss the roles of these processes in decreasing ER-protein load and inter-mechanism crosstalk.

Apoptosis in polycystic ovary syndrome: Mechanisms and therapeutic implications

Polycystic ovary syndrome (PCOS) is a common disorder that affects the female reproductive system, with an incidence of 8 % to 15 %. It is characterized by irregular menstruation, hyperandrogenemia, and polycystic abnormalities in the ovaries. Nevertheless, there is still much to learn about the molecular pathways underlying PCOS. Apoptosis is the process by which cells actively destroy themselves, and it is vital to an organism's ability to develop normally and maintain homeostasis. In recent years, a growing body of research has indicated a connection between the pathophysiology of PCOS and apoptosis. Therefore, it is critical to comprehend the relationship between PCOS and apoptosis in greater detail, identify the pathophysiological underpinnings of PCOS, and provide fresh perspectives and targets for its treatment. This review aims to summarize the relationship between PCOS and apoptosis, discuss how apoptosis affects normal ovarian function and how it becomes dysfunctional in the ovaries of PCOS patients, and investigate the signaling pathways associated with apoptosis in PCOS, including PI3K-Akt, TNF, NF-κB, and p53. Additionally, potential therapeutic approaches for PCOS treatment are provided by summarizing the role of apoptosis in PCOS therapy.

Are Mitochondria a Potential Target for Treating β-Thalassemia?

The inherited genetic disorder β-thalassemia affects the hematopoietic system and is caused by the low production or absence of adult hemoglobin (HbA). Ineffective erythropoiesis is the hallmark of β-thalassemia pathophysiology and is characterized by an erythropoietin-driven substantial increase in erythroblast proliferation, coupled with an increase in late-stage precursor apoptosis, which results in low levels of circulating mature red blood cells (RBCs) and chronic anemia. Mitochondrial dysfunction commonly occurs in these cells because of the increased demand for energy production and the need to manage abnormal hemoglobin chain synthesis. Moreover, several studies have highlighted the importance of gradual mitochondrial clearance for mature erythroid cell production. This review offers an overview of the mitochondrial role in essential cellular processes, particularly those crucial for maintaining RBC health and function. Additionally, recent evidence regarding the contribution of mitochondrial dysfunction to the pathophysiology and severity of β-thalassemia is discussed, along with updated insights into indirect mitochondria-targeting treatments, which present potential pharmacological targets.

Microglia programmed cell death in neurodegenerative diseases and CNS injury

Programmed cell death (PCD) has emerged as a critical regulatory mechanism in the initiation and progression of various pathological conditions. PCD in microglia, including necroptosis, pyroptosis, apoptosis, ferroptosis, and autophagy, occurs in a variety of central nervous system (CNS) diseases. Dysregulation of microglia can lead to excessive tissue damage or neuronal death in CNS injury. Various injury stimuli trigger aberrant activation of the PCD pathway of microglia, which then further leads to inflammatory cascades that exacerbates CNS pathology in a vicious cycle. Therefore, targeting PCD in microglia is considered an important avenue for the treatment of various neurodegenerative diseases and CNS injury. In this review, we summarize the major and recent findings focusing on the mechanisms of PCD in microglia modulating functions in neurodegenerative diseases and CNS injury and provide a systematic overview of the current inhibitors targeting various PCD pathways, which may provide important therapeutic targets that merit further investigation.

Molecular mechanisms of mitochondrial dynamics

Mitochondria not only synthesize energy required for cellular functions but are also involved in numerous cellular pathways including apoptosis, calcium homoeostasis, inflammation and immunity. Mitochondria are dynamic organelles that undergo cycles of fission and fusion, and these transitions between fragmented and hyperfused networks ensure mitochondrial function, enabling adaptations to metabolic changes or cellular stress. Defects in mitochondrial morphology have been associated with numerous diseases, highlighting the importance of elucidating the molecular mechanisms regulating mitochondrial morphology. Here, we discuss recent structural insights into the assembly and mechanism of action of the core mitochondrial dynamics proteins, such as the dynamin-related protein 1 (DRP1) that controls division, and the mitofusins (MFN1 and MFN2) and optic atrophy 1 (OPA1) driving membrane fusion. Furthermore, we provide an updated view of the complex interplay between different proteins, lipids and organelles during the processes of mitochondrial membrane fusion and fission. Overall, we aim to present a valuable framework reflecting current perspectives on how mitochondrial membrane remodelling is regulated.

MAPK14/AIFM2 pathway regulates mitophagy-dependent apoptosis to improve atrial fibrillation

OBJECTIVES

To investigate the role and mechanism of MAPK14/AIFM2 pathway in Ang II-induced atrial fibrillation in rats.

METHODS

A rat model of AF was established for in vivo experiments and HL-1 cells were treated with Ang II to develop an in vitro model. In addition, HL1 cells overexpressing AIFM2 (oeAIFM2) were constructed. SB203580 was used to inhibit the expression of MAPK14. The role of MAPK14 in Ang II-AF model was investigated by in vivo electrophysiological examination and molecular biology tests. The role of MAPK14 / AIFM2 pathway on AF induced by Ang II was explored in vitro.

RESULTS

MAPK14 and AIFM2 were significantly up-regulated in AF induced by Ang II (all P < 0.05). In vivo experiments indicated that inhibition of MAPK14 down-regulated AIFM2, improved atrial electrical conduction, AF inducibility and durations, and alleviated the structural and functional damage of heart and mitochondria (all P < 0.05). Both in vivo and in vitro tests showed that the MAPK14/AIFM2 pathway prevented Ang II-induced AF via regulating mitophagy-dependent apoptosis.

CONCLUSIONS

Inhibition of the MAPK14/AIFM2 pathway improved Ang II-induced AF by inhibiting mitophagy-dependent apoptosis.

SAMHD1 enhances HIV-1-induced apoptosis in monocytic cells via the mitochondrial pathway

Sterile alpha motif (SAM) and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1) inhibits HIV-1 replication in non-dividing cells by reducing the intracellular dNTP pool. SAMHD1 enhances spontaneous apoptosis in cells, but its effects on HIV-1-induced apoptosis and the underlying mechanisms remain unknown. Here we uncover a new mechanism by which SAMHD1 enhances HIV-1-induced apoptosis in monocytic cells through the mitochondrial pathway. We found that endogenous SAMHD1 enhances apoptosis levels induced by HIV-1 infection in dividing THP-1 cells. Mechanistically, SAMHD1 expression decreases the mitochondrial membrane potential and promotes cytochrome c release induced by HIV-1 infection in THP-1 cells, thereby enhancing mitochondrial apoptotic pathway. SAMHD1-enhanced apoptosis is associated with increased expression of the pro-apoptotic protein BCL-2-interacting killer (BIK) in cells. We further demonstrated that BIK contributes to SAMHD1-enhanced apoptosis during HIV-1 infection. Overall, our results reveal an unappreciated regulatory mechanism of SAMHD1 in enhancing HIV-1-induced apoptosis via the mitochondrial pathway in monocytic cells.

Enhanced anticancer efficacy of TRAIL-conjugated and odanacatib-loaded PLGA nanoparticles in TRAIL resistant cancer

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) demonstrates unique characteristics in anticancer therapies as it selectively induces apoptosis in cancer cells. However, most cancer cells are TRAIL-resistant. Odanacatib (ODN), a cathepsin K inhibitor, is considered a novel sensitizer for cancer treatment. Combination therapy between TRAIL and sensitizers is considered a potent platform that improves TRAIL-based anticancer therapies beyond TRAIL monotherapy. Herein, we developed ODN loaded poly(lactic-co-glycolic) nanoparticles conjugated to GST-TRAIL (TRAIL-ODN-PLGA-NPs) to target and treat TRAIL-resistant cancer. TRAIL-ODN-PLGA-NPs demonstrated a significant increase in cellular uptake via death receptors (DR5 and DR4) on surface of cancer cells. TRAIL-ODN-PLGA-NPs exposure destroyed more TRAIL-resistant cells compared to a single treatment with free drugs. The released ODN decreased the Raptor protein, thereby increasing damage to mitochondria by elevating reactive oxygen species (ROS) generation. Additionally, Bim protein stabilization improved TRAIL-resistant cell sensitization to TRAIL-induced apoptosis. The in vivo biodistribution study revealed that TRAIL-ODN-PLGA-NPs demonstrated high location and retention in tumor sites via the intravenous route. Furthermore, TRAIL-ODN-PLGA-NPs significantly inhibited xenograft tumor models of TRAIL-resistant Caki-1 and TRAIL-sensitive MDA-MB-231 cells.The inhibition was associated with apoptosis activation, Raptor protein stabilizing Bim protein downregulation, Bax accumulation, and mitochondrial ROS generation elevation. Additionally, TRAIL-ODN-PLGA-NPs affected the tumor microenvironment by increasing tumor necrosis factor-α and reducing interleukin-6. In conclusion, we evealed that our formulation demonstrated synergistic effects against TRAIL compared with the combination of free drug in vitro and in vivo models. Therefore, TRAIL-ODN-PLGA-NPs may be a novel candidate for TRAIL-induced apoptosis in cancer treatment.

Impact of quercetin on autophagy and apoptosis induced by a high concentration of CuSO4 in porcine ovarian granulosa cells

Copper is a vital micronutrient necessary for the maintenance of physiological functions. However, excessive amounts can lead to organ damage. Porcine ovarian granulosa cells are damaged by a high concentration of CuSO4, which can reduce the reproductive capacity of sows. Quercetin has shown remarkable efficacy in mitigating the harmful effects of heavy metals. Therefore, the aim of this study was to investigate the effects of a high concentration of CuSO4 on autophagy and apoptosis in porcine ovarian granulosa cells and to explore whether quercetin can counteract these toxic effect. Cell morphology, and the mRNA expression levels of autophagy-related genes (LC3-Ⅰ, ATG5, ATG7, ATG12, Beclin1, mTOR, LC3-Ⅱ and P62) were significantly changed upon treatment with 200 and 400 µM CuSO4. Treatment with 200 µM CuSO4 increased expression of P62 protein (P<0.05), promoted LC3-Ⅰ to LC3-Ⅱ conversion (P<0.05), and reduced PINK1 protein expression and the ATP content (P<0.05). In addition, expression of Caspase3 protein was increased and TUNEL staining indicated that the number of apoptotic cells was increased. However, co-treatment with 10 µM quercetin significantly decreased expression of P62 and conversion of LC3-Ⅰ to LC3-Ⅱ. Furthermore, flow cytometric analysis revealed that addition of 10 µM quercetin significantly reduced apoptosis induced by a high concentration of CuSO4. In summary, the results indicate that a high concentration of CuSO4 can trigger mitochondrial and autophagy dysfunction, activate mitochondrial apoptosis pathway, and exert cytotoxic effects. Quercetin can mitigate autophagy dysfunction, enhance autophagic processes, and alleviate apoptosis.

Therapeutic effect of novel drug candidate, PRG-N-01, on NF2 syndrome-related tumor

BACKGROUND

NF2-related schwannomatosis (NF2-SWN) is associated with multiple benign tumors in the nervous system. NF2-SWN, caused by mutations in the NF2 gene, has developed into intracranial and spinal schwannomas. Because of the high surgical risk and frequent recurrence of multiple tumors, targeted therapy is necessary. However, there are no approved drugs.

METHODS

We examined the action mechanism of PRG-N-01, a candidate molecule for NF2-SWN, through the direct binding assay and mass spectrometry. For in vitro anti-proliferative experiments, primary cells derived from NF2 mouse model and patient tumors, were treated with PRG-N-01. The in vivo therapeutic and preventive efficacy was validated via intraperitoneal and oral administration in NF2 mouse model (Postn-Cre; Nf2f/f). Gene expression profile in the DRG of mouse model was explored by RNA sequencing. The pharmacological properties of PRG-N-01 were analyzed through the preclinical study.

RESULTS

PRG-N-01 binds to the N-terminal extremity of TGFβR1 (TβR1) kinase domain, where TβR1 and RKIP interact, inhibiting the binding and preventing degradation of RKIP. In vivo administration in the mouse model suppressed schwannoma progression in the DRG. Early oral administration of the PRG-N-01 also demonstrated preventive effects on NF2-SWN. PRG-N-01 treatment suppressed tumor growth genes while upregulating genes related to for normal cell metabolism and schwann cell differentiation in DRG. PRG-N-01 showed druggable properties through the preclinical study including ADME, pharmacodynamics, pharmacokinetics and toxicology.

CONCLUSIONS

Together, our study provides the rationale and critical data for a prospective clinical trial of PRG-N-01 in NF2-SWN patients indicating PRG-N-01 as a promising candidate for the treatment.

Predictive models of sarcopenia based on inflammation and pyroptosis-related genes

Background

Sarcopenia is a prevalent condition associated with aging. Inflammation and pyroptosis significantly contribute to sarcopenia.

Methods

Two sarcopenia-related datasets (GSE111016 and GSE167186) were obtained from the Gene Expression Omnibus (GEO), followed by batch effect removal post-merger. The "limma" R package was utilized to identify differentially expressed genes (DEGs). Subsequently, LASSO analysis was conducted on inflammation and pyroptosis-related genes (IPRGs), resulting in the identification of six hub IPRGs. A novel skeletal muscle aging model was developed and validated using an independent dataset. Additionally, Gene Ontology (GO) enrichment analysis was performed on DEGs, along with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and gene set enrichment analysis (GSEA). ssGSEA was employed to assess differences in immune cell proportions between healthy muscle groups in older versus younger adults. The expression levels of the six core IPRGs were quantified via qRT-PCR.

Results

A total of 44 elderly samples and 68 young healthy samples were analyzed for DEGs. Compared to young healthy muscle tissue, T cell infiltration levels in aged muscle tissue were significantly reduced, while mast cell and monocyte infiltration levels were relatively elevated. A new diagnostic screening model for sarcopenia based on the six IPRGs demonstrated high predictive efficiency (AUC = 0.871). qRT-PCR results indicated that the expression trends of these six IPRGs aligned with those observed in the database.

Conclusion

Six biomarkers-BTG2, FOXO3, AQP9, GPC3, CYCS, and SCN1B-were identified alongside a diagnostic model that offers a novel approach for early diagnosis of sarcopenia.

Rhein: An Updated Review Concerning Its Biological Activity, Pharmacokinetics, Structure Optimization, and Future Pharmaceutical Applications

Rhein is a natural active ingredient in traditional Chinese medicine that has attracted much attention due to its wide range of pharmacological activities. However, its clinical application is limited by low water solubility, poor oral absorption, and potential toxicity to the liver and kidneys. Recently, advanced extraction and synthesis techniques have made it possible to develop derivatives of rhein, which have better pharmacological properties and lower toxicity. This article comprehensively summarizes the biological activity and action mechanism of rhein. Notably, we found that TGF-β1 is the target of rhein improving tissue fibrosis, while NF-κB is the main target of its anti-inflammatory effect. Additionally, we reviewed the current research status of the pharmacokinetics, toxicology, structural optimization, and potential drug applications of rhein and found that the coupling and combination therapy of rhein and other active ingredients exhibit a synergistic effect, significantly enhancing therapeutic efficacy. Finally, we emphasize the necessity of further studying rhein's pharmacological mechanisms, toxicology, and development of analogs, aiming to lay the foundation for its widespread clinical application as a natural product and elucidate its prospects in modern medicine.

Phosphorylation of cytochrome c at tyrosine 48 finely regulates its binding to the histone chaperone SET/TAF-Iβ in the nucleus

Post-translational modifications (PTMs) of proteins are ubiquitous processes present in all life kingdoms, involved in the regulation of protein stability, subcellular location and activity. In this context, cytochrome c (Cc) is an excellent case study to analyze the structural and functional changes induced by PTMS as Cc is a small, moonlighting protein playing different roles in different cell compartments at different cell-cycle stages. Cc is actually a key component of the mitochondrial electron transport chain (ETC) under homeostatic conditions but is translocated to the cytoplasm and even the nucleus under apoptotic conditions and/or DNA damage. Phosphorylation does specifically alter the Cc redox activity in the mitochondria and the Cc non-redox interaction with apoptosis-related targets in the cytoplasm. However, little is known on how phosphorylation alters the interaction of Cc with histone chaperones in the nucleus. Here, we report the effect of Cc Tyr48 phosphorylation by examining the protein interaction with SET/TAF-Iβ in the nuclear compartment using a combination of molecular dynamics simulations, biophysical and structural approaches such as isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR) and in cell proximity ligation assays. From these experiments, we infer that Tyr48 phosphorylation allows a fine-tuning of the Cc-mediated inhibition of SET/TAF-Iβ histone chaperone activity in vitro. Our findings likewise reveal that phosphorylation impacts the nuclear, stress-responsive functions of Cc, and provide an experimental framework to explore novel aspects of Cc post-translational regulation in the nucleus.

Cytochrome c and cancer cell metabolism: A new perspective

Cytochrome c is a vital electron carrier in the mitochondrial respiratory chain. When the outer membrane of mitochondria becomes permeable, cytochrome c is discharged into the cytoplasm, where it initiates the intrinsic apoptosis pathway. The complex interaction between cytochrome c and apoptosis protease-activating factor-1 (Apaf-1) leads to the formation of the apoptosome and activation of a cascade of caspases, highlighting the critical role of cytochrome c in controlling cell death mechanisms. Additionally, cytochrome c undergoes post-translational modifications, especially phosphorylation, which intricately regulate its roles in both respiration and apoptosis. These modifications add layers of complexity to how cytochrome c effectively controls cellular functions. cytochrome c becomes a lighthouse in the intricate web of cancer, its expression patterns providing hints about prognosis and paths toward treatment. Reduced levels of cytochrome c have been observed in cancer tissues, indicating a potential inhibition of apoptosis. For instance, in glioma tissues, cytochrome c levels were lower compared to healthy tissues, and this reduction became more pronounced in advanced stages of the disease. However, the role of cytochrome c in cancer becomes more intricate as it becomes intertwined with the metabolic reprogramming of cancer cells. This suggests that cytochrome c plays a crucial role in tumor progression and resistance to treatment. Viewing cytochrome c as a molecular mosaic reveals that it is not merely a protein, but also a central player in determining cellular fate. This realization opens up exciting avenues for potential advancements in cancer diagnosis and treatment strategies. Despite the advancements made, the narrative surrounding cytochrome c remains incomplete, urging further exploration into its complexities and the biological implications linked to cancer. cytochrome c stands as a beacon of hope and a promising target for therapy in the battle against cancer, particularly due to its significant involvement in tumor metabolism. It holds the potential for a future where innovative solutions can be developed to address the intricate challenges of cellular fate. In this review, we have endeavored to illuminate the multifaceted domain of cytochrome c drawing connections among apoptosis, metabolic reprogramming, and the Warburg effect in the context of cancer.

IDO2 Drives Autoantibody Production and Joint Inflammation in a Preclinical Model of Arthritis by Repressing Runx1 Function in B Cells

The immunomodulatory enzyme IDO2 is an essential mediator of autoantibody production and joint inflammation in preclinical models of autoimmune arthritis. Although originally identified as a tryptophan-catabolizing enzyme, we recently discovered a previously unknown nonenzymatic pathway is essential for the proarthritic function of IDO2. We subsequently identified Runx1 (Runt-related transcription factor 1) as a potential component of the nonenzymatic pathway IDO2 uses to drive arthritis. In this study, we find that IDO2 directly binds Runx1 and inhibits its localization to the nucleus, implicating Runx1 as a downstream component of IDO2 function. To directly test whether Runx1 mediates the downstream pathway driving B cell activation in arthritis, we bred B cell conditional Runx1-deficient (CD19cre Runx1flox/flox) mice onto the KRN.g7 arthritis model in the presence or absence of IDO2. Runx1 loss did not affect arthritis in the presence of IDO2; however, deleting Runx1 reversed the antiarthritic effect of IDO2 loss in this model. Further studies demonstrated that the IDO2-Runx1 interaction could be blocked with a therapeutic anti-IDO2 mAb in vitro and that Runx1 was required for IDO2 Ig's therapeutic effect in vivo. Taken together, these data demonstrate that IDO2 mediates autoantibody production and joint inflammation by acting as a repressor of Runx1 function in B cells and implicate therapeutic targeting of IDO2-Runx1 binding as a strategy to inhibit autoimmune arthritis and other autoantibody-mediated diseases.

A previously unidentified circRNA inhibits virus replication by regulating the miR-24-3p/KEAP1 axis

Circular RNAs (circRNAs) exert diverse biological functions in different processes. However, the role of circRNAs during virus infection is mostly unknown. Herein, we explored the characteristics of host circRNAs using alphaherpesvirus pseudorabies virus (PRV) as a model. PRV infection upregulated the expression of circRNA circ29164, which does not encode a protein. RNA pulldown assays identified that circ29164 interacts with the microRNA ssc-miRNA-24-3p. Further analysis indicated that ssc-miR-24-3p targets the mRNA encoding kelch-like ECH-associated protein 1 (KEAP1), and circ29164 competitively binds to ssc-miR-24-3p to prevent it binding to Keap1. Apoptosis detection demonstrated that circ29164 or Keap1 overexpression, but not knockdown, induced caspase 3 activity and the release of cytochrome C from mitochondria, and inhibited PRV replication. Taken together, these data identified a previously undiscovered circRNA, circ29164, which inhibits PRV replication by competitively binding to ssc-24-3p to maintain KEAP1 levels.

Ferroptosis contributes to the progression of female-specific neoplasms, from breast cancer to gynecological malignancies in a manner regulated by non-coding RNAs: Mechanistic implications

Ferroptosis, a recently identified type of non-apoptotic cell death, triggers the elimination of cells in the presence of lipid peroxidation and in an iron-dependent manner. Indeed, ferroptosis-stimulating factors have the ability of suppressing antioxidant capacity, leading to the accumulation of reactive oxygen species (ROS) and the subsequent oxidative death of the cells. Ferroptosis is involved in the pathophysiological basis of different maladies, such as multiple cancers, among which female-oriented malignancies have attracted much attention in recent years. In this context, it has also been unveiled that non-coding RNA transcripts, including microRNAs, long non-coding RNAs, and circular RNAs have regulatory interconnections with the ferroptotic flux, which controls the pathogenic development of diseases. Furthermore, the potential of employing these RNA transcripts as therapeutic targets during the onset of female-specific neoplasms to modulate ferroptosis has become a research hotspot; however, the molecular mechanisms and functional alterations of ferroptosis still require further investigation. The current review comprehensively highlights ferroptosis and its association with non-coding RNAs with a focus on how this crosstalk affects the pathogenesis of female-oriented malignancies, from breast cancer to ovarian, cervical, and endometrial neoplasms, suggesting novel therapeutic targets to decelerate and even block the expansion and development of these tumors.

Resilience in life and death: Metabolism and proteolysis in Bos indicus muscle and meat

Bos indicus cattle are important to beef production in hot, humid climates, but they have a reputation for producing tougher beef with more variability. Reduced and delayed degradation of muscle proteins postmortem is a major reason underlying these tenderness challenges. Inherent muscle metabolic characteristics and processing conditions shape the early dynamics of postmortem metabolism and protein degradation after harvest, which impacts subsequent tenderization. Skeletal muscles exhibit diverse metabolic and contractile properties, and metabolic pathways are coordinated to regulate flux under variable working conditions. Considering how living muscles respond and adapt to cellular stress may enhance our understanding of muscle death and quality development. The aim of this review is to examine how muscle properties influence metabolism and cellular response in the context of early postmortem muscle to meat conversion, and specifically, their potential contribution to variation in proteolysis in Bos indicus beef.

A novel thrombocytopenia-4-causing CYCS gene variant decreases caspase activity: Three-generation study

The CYCS gene is highly evolutionarily conserved, with only a few pathogenic variants that cause thrombocytopenia-4 (THC4). Here, we report a novel CYCS variant NM_018947.6: c.59C>T [NP_061820.1:p.(Thr20Ile)] segregating with thrombocytopenia in three generations of a Czech family. The phenotype of the patients corresponds to THC4 with platelets of normal size and morphology and dominant inheritance. Intriguingly, a gradual decline in platelet counts was observed across generations. CRISPR/Cas9-mediated gene editing was used to introduce the new CYCS gene variant into a megakaryoblast cell line (MEG-01). Subsequently, the adhesion, shape, size, ploidy, viability, mitochondrial respiration, cytochrome c protein (CYCS) expression, cell surface antigen expression and caspase activity were analysed in cells carrying the studied variant. Interestingly, the variant decreases the expression of CYCS while increasing mitochondrial respiration and the expression of CD9 cell surface antigen. Surprisingly, the variant abates caspase activation, contrasting with previously known effects of other CYCS variants. Some reports indicate that caspases may be involved in thrombopoiesis; thus, the observed dysregulation of caspase activity might contribute to thrombocytopenia. The findings significantly enhance our understanding of the molecular mechanisms underlying inherited thrombocytopenia and may have implications for diagnosis, prognosis and future targeted therapies.

Small molecules targeting mitochondria as an innovative approach to cancer therapy

Cellular death evasion is a defining characteristic of human malignancies and a significant contributor to therapeutic inefficacy. As a result of oncogenic inhibition of cell death mechanisms, established therapeutic regimens seems to be ineffective. Mitochondria serve as the cellular powerhouses, but they also function as repositories of self-destructive weaponry. Changes in the structure and activities of mitochondria have been consistently documented in cancer cells. In recent years, there has been an increasing focus on using mitochondria as a targeted approach for treating cancer. Considerable attention has been devoted to the development of delivery systems that selectively aim to deliver small molecules called "mitocans" to mitochondria, with the ultimate goal of modulating the physiology of cancer cells. This review summarizes the rationale and mechanism of mitochondrial targeting with small molecules in the treatment of cancer, and their impact on the mitochondria. This paper provides a concise overview of the reasoning and mechanism behind directing treatment towards mitochondria in cancer therapy, with a particular focus on targeting using small molecules. This review also examines diverse small molecule types within each category as potential therapeutic agents for cancer.

Mechanistic Insights into Influenza A Virus-Induced Cell Death and Emerging Treatment Strategies

Influenza A virus (IAV) infection initiates a complex interplay of cell death modalities, including apoptosis, necroptosis, pyroptosis, and their integration, known as PANoptosis, which significantly impacts host immune responses and tissue integrity. These pathways are intricately regulated by viral proteins and host factors, contributing to both viral clearance and pathogenesis-related tissue damage. This review comprehensively explores the molecular mechanisms underlying these cell death processes in influenza infection. We highlight the roles of key regulatory proteins, such as ZBP1 (Z-DNA binding protein 1) and RIPK3 (receptor-interacting protein kinase 3), in orchestrating these responses, emphasizing the dual roles of cell death in both antiviral defense and tissue injury. Furthermore, we discuss emerging therapeutic strategies targeting these pathways, aiming to enhance antiviral efficacy while minimizing collateral tissue damage. Future research should focus on targeted approaches to modulate cell death mechanisms, aiming to reduce tissue damage and improve clinical outcomes for patients with severe influenza.

Neobavaisoflavone Protects H9c2 Cells Against H2O2-Induced Mitochondrial Dysfunction Through ALOX15/PGC1-α Axis

Neobavaisoflavone (NBIF) is a natural antioxidant that has a variety of pharmacological activities. To investigate the effects of NBIF on oxidative stress-induced myocardial injury, H9c2 cells were treated with H2O2. Cell counting kit-8 was used to detect cell viability. Intracellular as well as lipid radicals were detected. To measure mitochondrial function, tetramethylrhodamine ethyl ester was used to detect mitochondrial membrane potential. 12- and 15-hydroxyeicosatetraenoic acids (HETE) were measured by LC-MS/MS. ALOX15, which is the upstream protein of 12-, 15-HETE, was also measured by using western blot analysis. The results showed that H2O2 induced lipid peroxidation in cardiomyocytes and caused mitochondrial dysfunction which was relieved by NBIF treatment. Besides, H2O2 significantly increased the production of 12-HETE and 15-HETE and upregulated the expression of ALOX15 while PGC-1α was downregulated and triggered the release of cytochrome c. The treatment of NBIF decreased the expression of ALOX15 and inhibited the activation of caspase-3. NBIF protected mitochondrial membrane integrity through increasing PGC-1α and Nrf1. Our results indicated that NBIF could protect cardiomyocytes against H2O2-induced mitochondrial dysfunction via ALOX15/PGC-1α axis.

Metabolic reprogramming tips vaccinia virus infection outcomes by stabilizing interferon-γ induced IRF1

Interferon (IFN) induced activities are critical, early determinants of immune responses and infection outcomes. A key facet of IFN responses is the upregulation of hundreds of mRNAs termed interferon-stimulated genes (ISGs) that activate intrinsic and cell-mediated defenses. While primary interferon signaling is well-delineated, other layers of regulation are less explored but implied by aberrant ISG expression signatures in many diseases in the absence of infection. Consistently, our examination of tonic ISG levels across uninfected human tissues and individuals revealed three ISG subclasses. As tissue identity and many comorbidities with increased virus susceptibility are characterized by differences in metabolism, we characterized ISG responses in cells grown in media known to favor either aerobic glycolysis (glucose) or oxidative phosphorylation (galactose supplementation). While these conditions over time had a varying impact on the expression of ISG RNAs, the differences were typically greater between treatments than between glucose/galactose. Interestingly, extended interferon-priming led to divergent expression of two ISG proteins: upregulation of IRF1 in IFN-γ/glucose and increased IFITM3 in galactose by IFN-α and IFN-γ. In agreement with a hardwired response, glucose/galactose regulation of interferon-γ induced IRF1 is conserved in unrelated mouse and cat cell types. In galactose conditions, proteasome inhibition restored interferon-γ induced IRF1 levels to that of glucose/interferon-γ. Glucose/interferon-γ decreased replication of the model poxvirus vaccinia at low MOI and high MOIs. Vaccinia replication was restored by IRF1 KO. In contrast, but consistent with differential regulation of IRF1 protein by glucose/galactose, WT and IRF1 KO cells in galactose media supported similar levels of vaccinia replication regardless of IFN-γ priming. Also associated with glucose/galactose is a seemingly second block at a very late stage in viral replication which results in reductions in herpes- and poxvirus titers but not viral protein expression. Collectively, these data illustrate a novel layer of regulation for the key ISG protein, IRF1, mediated by glucose/galactose and imply unappreciated subprograms embedded in the interferon response. In principle, such cellular circuitry could rapidly adapt immune responses by sensing changing metabolite levels consumed during viral replication and cell proliferation.

The pro-apoptotic function of the C. elegans BCL-2 homolog CED-9 requires interaction with the APAF-1 homolog CED-4

In Caenorhabditis elegans, apoptosis is inhibited by the BCL-2 homolog CED-9. Although canonically anti-apoptotic, CED-9 has a poorly understood pro-apoptotic function. CED-9 is thought to inhibit apoptosis by binding to and inhibiting the pro-apoptotic C. elegans APAF-1 homolog CED-4. We show that CED-9 or CED-4 mutations located in their CED-9-CED-4 binding regions reduce apoptosis without affecting the CED-9 anti-apoptotic function. These mutant CED-9 and CED-4 proteins are defective in a CED-9-CED-4 interaction in vitro and in vivo, revealing that the known CED-9-CED-4 interaction is required for the pro-apoptotic but not for the anti-apoptotic function of CED-9. The pro-apoptotic CED-9-CED-4 interaction occurs at mitochondria. In mammals, BCL-2 family members can activate APAF-1 via cytochrome c release from mitochondria. The conserved role of mitochondria in CED-9/BCL-2-dependent CED-4/APAF-1 activation is notable and suggests that understanding how CED-9 promotes apoptosis in C. elegans could inform the understanding of mammalian apoptosis and how disruptions of apoptosis promote certain human disorders.

F-ATP synthase inhibitory factor 1 and mitochondria-organelle interactions: New insight and implications

Mitochondria are metabolic hub, and act as primary sites for reactive oxygen species (ROS) and metabolites generation. Mitochondrial Ca2+ uptake contributes to Ca2+ storage. Mitochondria-organelle interactions are important for cellular metabolic adaptation, biosynthesis, redox balance, cell fate. Organelle communications are mediated by Ca2+/ROS signals, vesicle transport and membrane contact sites. The permeability transition pore (PTP) is an unselective channel that provides a release pathway for Ca2+/ROS, mtDNA and metabolites. F-ATP synthase inhibitory factor 1 (IF1) participates in regulation of PTP opening and is required for the translocation of transcriptional factors c-Myc/PGC1α to mitochondria to stimulate metabolic switch. IF1, a mitochondrial specific protein, has been suggested to regulate other organelles including nucleus, endoplasmic reticulum and lysosomes. IF1 may be able to mediate mitochondria-organelle interactions and cellular physiology through regulation of PTP activity.

Metabolic reprogramming tips vaccinia virus infection outcomes by stabilizing interferon-γ induced IRF1

Interferon (IFN) induced activities are critical, early determinants of immune responses and infection outcomes. A key facet of IFN responses is the upregulation of hundreds of mRNAs termed interferon-stimulated genes (ISGs) that activate intrinsic and cell-mediated defenses. While primary interferon signaling is well-delineated, other layers of regulation are less explored but implied by aberrant ISG expression signatures in many diseases in the absence of infection. Consistently, our examination of tonic ISG levels across uninfected human tissues and individuals revealed three ISG subclasses. As tissue identity and many comorbidities with increased virus susceptibility are characterized by differences in metabolism, we characterized ISG responses in cells grown in media known to favor either aerobic glycolysis (glucose) or oxidative phosphorylation (galactose supplementation). While these conditions over time had a varying impact on the expression of ISG RNAs, the differences were typically greater between treatments than between glucose/galactose. Interestingly, extended interferon-priming led to divergent expression of two ISG proteins: upregulation of IRF1 in IFN-γ/glucose and increased IFITM3 in galactose by IFN-α and IFN-γ. In agreement with a hardwired response, glucose/galactose regulation of interferon-γ induced IRF1 is conserved in unrelated mouse and cat cell types. In galactose conditions, proteasome inhibition restored interferon-γ induced IRF1 levels to that of glucose/interferon-γ. Glucose/interferon-γ decreased replication of the model poxvirus vaccinia at low MOI and high MOIs. Vaccinia replication was restored by IRF1 KO. In contrast, but consistent with differential regulation of IRF1 protein by glucose/galactose, WT and IRF1 KO cells in galactose media supported similar levels of vaccinia replication regardless of IFN-γ priming. Also associated with glucose/galactose is a seemingly second block at a very late stage in viral replication which results in reductions in herpes- and poxvirus titers but not viral protein expression. Collectively, these data illustrate a novel layer of regulation for the key ISG protein, IRF1, mediated by glucose/galactose and imply unappreciated subprograms embedded in the interferon response. In principle, such cellular circuitry could rapidly adapt immune responses by sensing changing metabolite levels consumed during viral replication and cell proliferation.

Role of mitochondrial reactive oxygen species in chemically-induced ferroptosis

Ferroptosis is a form of iron-dependent regulated cell death which is different from apoptosis. Chemically-induced ferroptosis is characterized by an accumulation of lipid reactive oxygen species (ROS) in the cells. A number of earlier studies have suggested the involvement of mitochondrial ROS in ferroptosis, and the present study seeks to further investigate the role of mitochondrial ROS in the induction of chemically-induced ferroptotic cell death. We find that during erastin-induced, glutathione depletion-associated ferroptosis, mitochondrial ROS accumulation is an important late event, which likely is involved in the final execution of ferroptotic cell death. The mitochondrion-originated ROS is found to accumulate in large quantities inside the nuclei during the late phases of erastin-induced ferroptosis. Completion of the late-phase accumulation of mitochondrion-produced ROS inside the nucleus of a cell likely marks an irreversible point in the cell death process. Similarly, accumulation of large amounts of mitochondrion-produced ROS inside the nucleus is also observed in the late phases of RSL3-induced ferroptosis. The results of this study indicate that the mitochondrial ROS play an important role in the final steps of both erastin- and RSL3-induced ferroptotic cell death.

White light increases anticancer effectiveness of iridium(III) complexes toward lung cancer A549 cells

Anticancer activity has been extensively studies. In this article, three ligands 2-(6-bromobenzo[d][1,3]dioxol-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (BDIP), 2-(7-methoxybenzo[d][1,3]dioxol-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (MDIP), 2-(6-nitrobenzo[d][1,3]dioxol-5-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (NDIP) and their iridium(III) complexes: [Ir(ppy)2(BDIP)](PF6) (ppy = deprotonated 2-phenylpyridine, 3a), [Ir(ppy)2(MDIP)](PF6) (3b) and [Ir(ppy)2(NDIP)](PF6) (3c) were synthesized. The cytotoxicity of 3a, 3b, 3c against Huh7, A549, BEL-7402, HepG2, HeLa, and non-cancer NIH3T3 was tested using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The results obtained from the MTT test stated clearly that these complexes demonstrated moderate or non-cytotoxicity toward Huh7, BEL-7402, HepG2 and HeLa except A549 cells. To improve the anticancer efficacy, we used white light to irradiate the mixture of cells and complexes for 30 min, the anticancer activity of the complexes was greatly enhanced. Particularly, 3a and 3b exhibited heightened capability to inhibit A549 cells proliferation with IC50 (half maximal inhibitory concentration) values of 0.7 ± 0.3 μM and 1.8 ± 0.1 μM, respectively. Cellular uptake has shown that 3a and 3b can be accumulated in the cytoplasm. Wound healing and colony forming showed that 3a and 3b significantly hinder the cell migration and growth in the S phase. The complexes open mitochondrial permeability transition pore (MPTP) channel and cause the decrease of membrane potential, release of cytochrome C, activation of caspase 3, and finally lead to apoptosis. In addition, 3a and 3b cause autophagy, increase the lipid peroxidation and lead to ferroptosis. Also, 3a and 3b increase the expression of calreticulin (CRT), high mobility group box 1 (HMGB1), heat shock protein 70 (HSP70), thereby inducing immunogenic cell death.

Permeabilization of the outer mitochondrial membrane: Mechanisms and consequences

Permeabilization of the outer mitochondrial membrane is а physiological process that can allow certain molecules to pass through it, such as low molecular weight solutes required for cellular respiration. This process is also important for the development of various modes of cell death. Depending on the severity of this process, cells can die by autophagy, apoptosis, or necrosis/necroptosis. Distinct types of pores can be opened at the outer mitochondrial membrane depending on physiological or pathological stimuli, and different mechanisms can be activated in order to open these pores. In this comprehensive review, all these types of permeabilization, the mechanisms of their activation, and their role in various diseases are discussed.

Phospholipid Scramblase Activity of VDAC Dimers: New Implications for Cell Death, Autophagy and Ageing

Voltage-dependent anion channels (VDACs) are important proteins of the outer mitochondrial membrane (OMM). Their beta-barrel structure allows for efficient metabolite exchange between the cytosol and mitochondria. VDACs have further been implicated in the control of regulated cell death. Historically, VDACs have been pictured as part of the mitochondrial permeability transition pore (MPTP). New concepts of regulated cell death involving VDACs include its oligomerisation to form a large pore complex in the OMM; however, alternative VDAC localisation to the plasma membrane has been suggested in the literature and will be discussed regarding its potential role during cell death. Very recently, a phospholipid scramblase activity has been attributed to VDAC dimers, which explains the manifold lipidomic changes observed in VDAC-deficient yeast strains. In this review, I highlight the recent advances regarding VDAC's phospholipid scramblase function and discuss how this new insight sheds new light on VDAC's implication in regulated cell death, autophagy, and ageing.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

Erythropoietin Reduces Inflammation, Oxidative Stress, and Apoptosis in a Rat Model of Bleomycin-Induced Idiopathic Pulmonary Fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a lethal interstitial disease with unknown etiology and no effective cure, posing a great health burden to society. Erythropoietin (EPO) has been demonstrated to have protective roles in various tissues such as brain, spinal cord, heart, kidney and lung tissues. In this study, we investigate the specific anti-inflammatory, antioxidant and antiapoptotic effects of erythropoietin on lung tissue in a bleomycin-induced rat model of idiopathic pulmonary fibrosis.

METHODS

Recombinant human EPO or saline was injected, and the animals were monitored for 14 days after bleomycin instillation. Their hematocrit and serum EPO levels were determined. Histological and immunohistochemical analyses were performed.

RESULTS

The extent of tissue injury, determined through morphometric analysis, was significantly decreased in size in animals treated with erythropoietin. An immunohistochemical analysis of the expression of cyclooxygenase-2 (COX-2), inducible synthase of nitric oxide (i-NOS), metalloproteinase-9 (MMP-9), erythropoietin receptor (EPO-R), and cytochrome-C (cyt-C) found these enzymes to be decreased in a statistically significant manner in animals treated with erythropoietin when compared to a non-treated group.

CONCLUSIONS

The reduced expression of COX-2, i-NOS, MMP-9, EPO-R, and i-NOS in the lung tissues of animals treated with EPO indicates the anti-inflammatory, antioxidant and antiapoptotic action of erythropoietin, suggesting its potential therapeutic role in pulmonary fibrosis.

Comparative cytotoxicity of Acanthamoeba castellanii-derived conditioned medium on human corneal epithelial and stromal cells

Soluble factors in the secretome of Acanthamoeba castellanii play crucial roles in the pathogenesis of Acanthamoeba keratitis (AK). Investigating the pathological effects of A. castellanii-derived conditioned medium (ACCM) on ocular cells can provide insights into the damage inflicted during AK. This study examined ACCM-induced cytotoxicity in primary human corneal stromal cells (CSCs) and a human SV40 immortalized corneal epithelial cell line (ihCECs) at varying ACCM concentrations (25 %, 50 %, 75 %, and 100 %). MTT, AlamarBlue, Sulforhodamine B, lactate dehydrogenase, and Caspase-3/7 activation assays were used to assess the impact of ACCM on the cell viability, proliferation and apoptosis. Additionally, fluorescent staining was used to reveal actin cytoskeleton changes. ACCM exposure significantly decreased cell viability, increased apoptosis, and disrupted the actin cytoskeleton, particularly at higher concentrations and longer exposures. Proteases were found to mediate these cytopathogenic effects, highlighting the need for characterization of A. castellanii proteases as key virulence factors in AK pathogenesis.

The iron maiden: Oligodendroglial metabolic dysfunction in multiple sclerosis and mitochondrial signaling

Multiple sclerosis (MS) is an autoimmune disease, governed by oligodendrocyte (OL) dystrophy and central nervous system (CNS) demyelination manifesting variable neurological impairments. Mitochondrial mechanisms may drive myelin biogenesis maintaining the axo-glial unit according to dynamic requisite demands imposed by the axons they ensheath. The promotion of OL maturation and myelination by actively transporting thyroid hormone (TH) into the CNS and thereby facilitating key transcriptional and metabolic pathways that regulate myelin biogenesis is fundamental to sustain the profound energy demands at each axo-glial interface. Deficits in regulatory functions exerted through TH for these physiological roles to be orchestrated by mature OLs, can occur in genetic and acquired myelin disorders, whereby mitochondrial efficiency and eventual dysfunction can lead to profound oligodendrocytopathy, demyelination and neurodegenerative sequelae. TH-dependent transcriptional and metabolic pathways can be dysregulated during acute and chronic MS lesion activity depriving OLs from critical acetyl-CoA biochemical mechanisms governing myelin lipid biosynthesis and at the same time altering the generation of iron metabolism that may drive ferroptotic mechanisms, leading to advancing neurodegeneration.

Autophagy in aging-related diseases and cancer: Principles, regulatory mechanisms and therapeutic potential

Macroautophagy/autophagy is primarily accountable for the degradation of damaged organelles and toxic macromolecules in the cells. Regarding the essential function of autophagy for preserving cellular homeostasis, changes in, or dysfunction of, autophagy flux can lead to disease development. In the current paper, the complicated function of autophagy in aging-associated pathologies and cancer is evaluated, highlighting the underlying molecular mechanisms that can affect longevity and disease pathogenesis. As a natural biological process, a reduction in autophagy is observed with aging, resulting in an accumulation of cell damage and the development of different diseases, including neurological disorders, cardiovascular diseases, and cancer. The MTOR, AMPK, and ATG proteins demonstrate changes during aging, and they are promising therapeutic targets. Insulin/IGF1, TOR, PKA, AKT/PKB, caloric restriction and mitochondrial respiration are vital for lifespan regulation and can modulate or have an interaction with autophagy. The specific types of autophagy, such as mitophagy that degrades mitochondria, can regulate aging by affecting these organelles and eliminating those mitochondria with genomic mutations. Autophagy and its specific types contribute to the regulation of carcinogenesis and they are able to dually enhance or decrease cancer progression. Cancer hallmarks, including proliferation, metastasis, therapy resistance and immune reactions, are tightly regulated by autophagy, supporting the conclusion that autophagy is a promising target in cancer therapy.

Modulating Mitochondrial DNA Heteroplasmy with Mitochondrially Targeted Endonucleases

Mitochondria, mainly known as energy factories of eukaryotic cells, also exert several additional signaling and metabolic functions and are today recognized as major cellular biosynthetic and signaling hubs. Mitochondria possess their own genome (mitochondrial DNA-mtDNA), that encodes proteins essential for oxidative phosphorylation, and mutations in it are an important contributor to human disease. The mtDNA mutations often exist in heteroplasmic conditions, with both healthy and mutant versions of the mtDNA residing in patients' cells and the level of mutant mtDNA may vary between different tissues and organs and affect the clinical outcome of the disease. Thus, shifting the ratio between healthy and mutant mtDNA in patients' cells provides an intriguing therapeutic option for mtDNA diseases. In this review we describe current strategies for modulating mitochondrial heteroplasmy levels with engineered endonucleases including mitochondrially targeted TALENs and Zinc finger nucleases (ZFNs) and discuss their therapeutic potential. These gene therapy tools could in the future provide therapeutic help both for patients with mitochondrial disease as well as in preventing the transfer of pathogenic mtDNA mutations from a mother to her offspring.

Toxin-derived peptides: An unconventional approach to alleviating cerebral stroke burden and neurobehavioral impairments

Cerebral stroke is a pressing global health concern, ranking as the second leading cause of mortality and resulting in persistent neurobehavioral impairments. Cerebral strokes, triggered by various embolic events, initiate complex signaling pathways involving neuroexcitotoxicity, ionic imbalances, inflammation, oxidative stress, acidosis, and mitochondrial dysfunction, leading to programmed cell death. Currently, the FDA has approved tissue plasminogen activator as a relatively benign intervention for cerebral stroke, leaving a significant treatment gap. However, a promising avenue has emerged from Earth's toxic creatures. Animal venoms harbor bioactive molecules, particularly neuropeptides, with potential in innovative healthcare applications. These venomous components, affecting ion channels, receptors, and transporters, encompass neurochemicals, amino acids, and peptides, making them prime candidates for treating cerebral ischemia and neurological disorders. This review explores the composition, applications, and significance of toxin-derived peptides as viable therapeutic agents. It also investigates diverse toxins from select venomous creatures, with the primary objective of shedding light on current stroke treatments and paving the way for pioneering therapeutic strategies capable of addressing neurobehavioral deficits.

No Time to Die: How Cytomegaloviruses Suppress Apoptosis, Necroptosis, and Pyroptosis

Viruses are obligate intracellular pathogens as their replication depends on the metabolism of the host cell. The induction of cellular suicide, known as programmed cell death (PCD), has the potential to hinder viral replication and act as a first line of defense against viral pathogens. Apoptosis, necroptosis, and pyroptosis are three important PCD modalities. Different signaling pathways are involved in their execution, and they also differ in their ability to cause inflammation. Cytomegaloviruses (CMV), beta-herpesviruses with large double-stranded DNA genomes, encode a great variety of immune evasion genes, including several cell death suppressors. While CMV inhibitors of apoptosis and necroptosis have been known and studied for years, the first pyroptosis inhibitor has been identified and characterized only recently. Here, we describe how human and murine CMV interfere with apoptosis, necroptosis, and pyroptosis signaling pathways. We also discuss the importance of the different PCD forms and their viral inhibitors for the containment of viral replication and spread in vivo.

Cell death as an architect of adult skin stem cell niches

Our skin provides a physical and immunological barrier against dehydration and environmental insults ranging from microbial attacks, toxins and UV irradiation to wounding. Proper functioning of the skin barrier largely depends on the interplay between keratinocytes- the epithelial cells of the skin- and immune cells. Two spatially distinct populations of keratinocyte stem cells (SCs) maintain the epidermal barrier function and the hair follicle. These SCs are inherently long-lived, but cell death can occur within their niches and impacts their functionality. The default cell death programme in skin is apoptosis, an orderly and non-inflammatory suicide programme. However, recent findings are shedding light on the significance of various modes of regulated necrotic cell death, which are lytic and can provoke inflammation within the local skin environment. While the presence of dying cells was generally regarded as a mere consequence of inflammation, findings in various human dermatological conditions and experimental mouse models of aberrant cell death control demonstrated that cell death programmes in keratinocytes (KCs) can drive skin inflammation and even tumour initiation. When cells die, they need to be removed by phagocytosis and KCs can function as non-professional phagocytes of apoptotic cells with important implications for their SC capacities. It is becoming apparent that in conditions of heightened SC activity, distinct cell death modalities differentially impact the different skin SC populations in their local niches. Here, we describe how regulated cell death modalities functionally affect epidermal SC niches along with their relevance to injury repair, inflammatory skin disorders and cancer.