Depolarization Of Mitochondrial Membrane Potential Research Articles

Spermidine attenuates left ventricular dysfunction in estrogen deprived aging rats through mitigating lipid peroxidation and mitochondrial dysfunction

Abstract Background Aging women with postmenopause are particularly susceptible to cardiovascular diseases (CVDs), which are associated with the elevation of oxidative stress and mitochondrial dysfunction. Although hormone replacement therapy (HRT) has been reported to provide cardiometabolic protection, long-term HRT could be linked to CVD consequences. A novel organic therapy with spermidine has shown promise as cardioprotection in several CVDs. However, the effects of spermidine on left ventricular (LV) function, mitochondrial function and oxidative stress in estrogen-deprived aging rats have not been investigated. Purpose To evaluate the effects of spermidine on LV function, mitochondrial function and oxidative stress in estrogen-deprived and D-galactose-induced aging rats Methods Twenty female Wistar rats were randomly assigned to the sham and the ovariectomy (OVX) along with D-galactose (150 mg/kg/day, s.c.) administration throughout the experiment for 12 weeks. OVX with D-galactose-treated rats were divided into three interventional groups: vehicle (ODV), spermidine (20 mg/kg/day, p.o., ODS), and estradiol (50 ug/kg/day, s.c., ODE) (n=5/group) for 8 weeks. The sham group received a vehicle (SVV, n=5). At the end, all rats underwent echocardiography, followed by euthanasia. The hearts were removed for measuring mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (MMP) changes (ΔΨm), and malondialdehyde (MDA) levels. Results Rats with OVX-induced estrogen deprivation with D-galactose-induced aging had LV impairments indicated by decreased LV ejection fraction, reduced ratio of peak velocity blood flow from left ventricular relaxation in early diastole (E) to peak velocity flow by atrial contraction (A), and increased sympathovagal imbalance (elevated low/high frequency (LF/HF) ratio) (Fig. 1A-C). These estrogen-deprived aging rats also had an increase in cardiac tissue MDA levels, mitochondrial ROS production, and MMP depolarization (Fig. 1D-F). Both spermidine and estrogen similarly demonstrated a significant reduction in all of those detrimental effects, leading to improved LV function (Fig. 1A-F). Conclusion Spermidine exerted cardioprotection comparable to estrogen supplement through mitigating oxidative stress and mitochondrial impairments in cardiac tissue, resulting in improved LV dysfunction and cardiac autonomic balance due to estrogen deprived aging conditions in rats. These findings suggest that spermidine administration could be a promising strategy for cardioprotection in postmenopausal women with aging.

Pseudorabies virus infection triggers mitophagy to dampen the interferon response and promote viral replication.

Pseudorabies virus (PRV) utilizes multiple strategies to inhibit type I interferon (IFN-I) production and signaling to achieve innate immune evasion. Among several other functions, mitochondria serve as a crucial immune hub in the initiation of innate antiviral responses. It is currently unknown whether PRV inhibits innate immune responses by manipulating mitochondria. In this study, we found that PRV infection damages mitochondrial structure and function, as shown by mitochondrial membrane potential depolarization, reduction in mitochondrial numbers, and an imbalance in mitochondrial dynamics. In addition, PRV infection triggered PINK1-Parkin-mediated mitophagy to eliminate the impaired mitochondria, which resulted in a suppression of IFN-I production, thereby promoting viral replication. Furthermore, we found that mitophagy resulted in the degradation of the mitochondrial antiviral signaling protein, which is located on the mitochondrial outer membrane. In conclusion, the data of the current study indicate that PRV-induced mitophagy represents a previously uncharacterized PRV evasion mechanism of the IFN-I response, thereby promoting virus replication.IMPORTANCEPseudorabies virus (PRV), a pathogen that induces different disease symptoms and is often fatal in domestic animals and wildlife, has caused great economic losses to the swine industry. Since 2011, different PRV variant strains have emerged in Asia, against which current commercial vaccines may not always provide optimal protection in pigs. In addition, there are indications that some of these PRV variant strains may sporadically infect people. In the current study, we found that PRV infection causes mitochondria injury. This is associated with the induction of mitophagy to eliminate the damaged mitochondria, which results in suppressed antiviral interferon production and signaling. Hence, our study reveals a novel mechanism that is used by PRV to antagonize the antiviral host immune response, providing a theoretical basis that may contribute to the research toward and development of new vaccines and antiviral drugs.

Unveiling the roles of CaSDH8 in Candida albicans: Implications for virulence and azole resistance

ABSTRACT Candida albicans is the most common pathogen in systemic fungal diseases, exhibits a complex pathogenic mechanism, and is increasingly becoming drug tolerant. Therefore, it is particularly important to study the genes associated with virulence and resistance of C. albicans. Here, we identified a gene (orf19.1588) that encodes a conserved mitochondrial protein known as CaSDH8, upon deletion of CaSdh8, the deleted strain (Casdh8Δ/Δ) experienced impaired growth, hyphal development, and virulence. Casdh8Δ/Δ displayed a reduced capacity to utilize alternative carbon sources, along with detrimental alterations in reactive oxygen species (ROS), mitochondrial membrane potential (MMP) depolarization, and adenosine triphosphate (ATP) levels. Interestingly, Casdh8Δ/Δ demonstrated resistance to azole drugs, and under the influence of fluconazole, the cell membrane permeability and mitochondrial function of Casdh8Δ/Δ were less compromised than those of the wild type, indicating a reduction in the detrimental effects of fluconazole on Casdh8Δ/Δ. These findings highlight the significance of CaSDH8 as a crucial gene for the maintenance of cellular homoeostasis. Our study is the first to document the effects of the CaSDH8 gene on the virulence and azole resistance of C. albicans at both the molecular and animal levels, providing new clues and directions for the antifungal infection and the discovery of antifungal drug targets.

Zhachong Shisanwei pill drug-containing serum protects H2O2-Induced PC12 cells injury by suppressing apoptosis, oxidative stress via regulating the MAPK signaling pathway.

Zhachong Shisanwei Pill (ZSP) is a classical Mongolian formula that combines 13 types of Chinese medicinal materials and has been used for treating ischemic stroke (IS) for centuries. However, the underlying molecular mechanisms have yet to be fully elucidated. The aim of this study is to explore potential mechanism of ZSP on nerve cells in cerebral ischemic injury. To simulate the pathological process of oxidative stress following IS, an injury model using PC12 cells was induced with hydrogen peroxide (H2O2). Afterward, PC12 cells were treated with ZSP medicated serum at low, medium, and high doses. Various assays were conducted to assess cell viability and oxidative stress indicators, including lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), reactive oxygen species (ROS), and mitochondrial membrane potential (MMP). Cell apoptosis was evaluated through morphological assessment and flow cytometry. Additionally, the expression levels of apoptosis-related proteins (Bcl-2, Bax, Caspase-9, Caspase-3, PARP) and signaling pathway proteins (JNK, phosphorylated JNK, ERK, phosphorylated ERK, p38, and phosphorylated p38) were measured using automated Western blotting. Our findings indicate that ZSP medicated serum preconditioning improves the condition of PC12 cells injured by H2O2. Specifically, it increased cell survival rates and reduced LDH release. Additionally, ZSP treatment decreased ROS levels and MDA content, while enhancing the activity of SOD and CAT in the injured PC12 cells. ZSP also reversed the depolarization of mitochondrial membrane potential and protected cells from apoptosis by modulating the expression of apoptosis-related proteins, including Bcl-2, Bax, Caspase-9, Caspase-3, and PARP. Furthermore, the overactivation of the MAPK signaling pathway due to H2O2-induced injury was inhibited, as evidenced by the downregulation of phosphorylated JNK, ERK, and p38 levels. Mongolian medicine ZSP demonstrates protective effects against H2O2-induced oxidative stress and apoptosis in PC12 cells. The underlying mechanism may involve the inhibition of the MAPK signaling pathway, enhancement of antioxidant enzyme activity, reduction of intracellular peroxidation levels, and suppression of intrinsic apoptosis pathways.

Mitochondrial membrane potential and oxidative stress interact to regulate Oma1-dependent processing of Opa1 and mitochondrial dynamics.

Mitochondrial form and function are regulated by the opposing forces of mitochondrial dynamics: fission and fusion. Mitochondrial dynamics are highly active and consequential during neuronal ischemia/reperfusion (I/R) injury. Mitochondrial fusion is executed at the mitochondrial inner membrane by Opa1. The balance of long (L-Opa1) and proteolytically cleaved short (S-Opa1) isoforms is critical for efficient fusion. Oma1 is the predominant stress-responsive protease for Opa1 processing. In neuronal cell models, we assessed Oma1 and Opa1 regulation during mitochondrial stress. In an immortalized mouse hippocampal neuron line (HT22), Oma1 was sensitive to mitochondrial membrane potential depolarization (rotenone, FCCP) and hyperpolarization (oligomycin). Further, oxidative stress was sufficient to increase Oma1 activity and necessary for depolarization-induced proteolysis. We generated Oma1 knockout (KO) HT22 cells that displayed normal mitochondrial morphology and fusion capabilities. FCCP-induced mitochondrial fragmentation was exacerbated in Oma1 KO cells. However, Oma1 KO cells were better equipped to perform restorative fusion after fragmentation, presumably due to preserved L-Opa1. We extended our investigations to a combinatorial stress of neuronal oxygen-glucose deprivation and reoxygenation (OGD/R), where we found that Opa1 processing and Oma1 activation were initiated during OGD in an ROS-dependent manner. These findings highlight a novel dependence of Oma1 on oxidative stress in response to depolarization. Further, we demonstrate contrasting fission/fusion roles for Oma1 in the acute response and recovery stages of mitochondrial stress. Collectively, our results add intersectionality and nuance to the previously proposed models of Oma1 activity.

Dexmedetomidine ameliorates diabetic intestinal injury by promoting the polarization of M2 macrophages through the MMP23B pathway.

Diabetes is often associated with gastrointestinal dysfunctions, which can lead to hypoglycemia. Dexmedetomidine (DEX) is a commonly used sedative in perioperative diabetic patients and may affect gastrointestinal function. To investigate whether sedative doses of DEX alleviate diabetes-caused intestinal dysfunction. Sedation/anesthesia scores and vital signs of streptozotocin (STZ)-induced diabetic mice under DEX sedation were observed. Diabetic mice were divided into saline and DEX groups. After injecting sedatives intraperitoneally, tight junctions (TJs) and apoptotic levels were evaluated 24 hours later to assess the intestinal barrier function. The role of DEX was validated using Villin-MMP23B flox/flox mice with intestinal epithelial deletion. In vitro, high glucose and hyperosmolarity were used to culture Caco-2 monolayer cells with STZ inter-vention. Immunofluorescence techniques were used to monitor the barrier and mitochondrial functions. MMP23B protein levels in the intestinal tissue of STZ-induced diabetic mice were significantly higher than those in the intestinal tissue of control mice, with the DEX group displaying decreased MMP23B levels. Diabetes-mediated TJ dis-ruption, increased intestinal mucosal permeability, and systemic inflammation in wild-type mice might be reversed by DEX. In Caco-2 cells, MMP23B was associated with increased reactive oxygen species accumulation, mitochondrial membrane potential depolarization, and TJ disruption. DEX reduces MMP23B, which may potentially contribute to STZ-induced intestinal barrier dysfunction, affecting TJ modification through mitochondrial dysfunction.

The role of rapamycin in the PINK1/Parkin signaling pathway in mitophagy in podocytes.

This study aimed to clarify the role of rapamycin in the PINK1/Parkin signaling pathway in mitophagy in podocytes and the role of voltage-dependent anion channel 1 (VDAC1) in the PINK1/Parkin signaling pathway in mouse glomerular podocytes. For this purpose, podocytes were cultured with rapamycin and observed using microscopy. The apoptosis rate of podocytes was detected by flow cytometry. Changes in the mitochondrial membrane potential were measured. The autophagy-related proteins VDAC1, PINK1, Parkin, and LC3 were detected, and mitochondrial autophagosomes were observed via transmission electron microscopy. In the present study, we demonstrated that the number of podocytes treated with rapamycin was significantly reduced. Compared with those in the control group, the apoptosis rate of podocytes and the degree of mitochondrial membrane potential depolarization were significantly higher. We also found the expression levels of VDAC1, PINK1, Parkin, and LC3 were significantly increased. In the rapamycin-treated group, the numbers of swollen mitochondria and mitochondrial autophagosomes were significantly higher. Finally, we showed that rapamycin can upregulate the expression of VDAC1, PINK1, Parkin, and LC3 in glomerular podocytes, which is correlated with mitophagy. VDAC1 is involved in mitophagy and is related to the PINK1/Parkin signaling pathway, serving as an indicator of mitophagy in podocytes.

TUBB4A Inhibits Glioma Development by Regulating ROS-PINK1/Parkin-Mitophagy Pathway.

Glioma is a refractory malignant tumor with a powerful capacity for invasiveness and a poor prognosis. This study aims to investigate the role and mechanism of tubulin beta class IVA (TUBB4A) in glioma progression. The differential expression of TUBB4A in humans was obtained from databases and analyzed. Glioma cells U251-MG and U87-MG were intervened by pcDNA3.1(+) and TUBB4A overexpression plasmid. MTT, CCK8, LDH, wound healing, transwell, and western blotting were used to explore whether TUBB4A participates in the development of glioma. Reactive oxygen species (ROS) were detected by the DCFH-DA probe. Mitochondrial membrane potential (MMP) was examined by JC-1. It was found thatTUBB4A expression level correlated with tumor grade, IDH1 status,1p/19q status, and poor survival in glioma patients. In addition, TUBB4A overexpression inhibited the proliferation, migration, and invasion of U251-MG and U87-MG, while increasing the degree of apoptosis. Notably, TUBB4A overexpression promotes ROS generation and MMP depolarization, and induces mitophagy through the PINK1/Parkin pathway. Interestingly, mitochondria-targeted ROS scavenger reversed the effect of TUBB4A overexpression on PINK1/Parkin expression and mitophagy, whereas mitophagy inhibitor did not affect ROS production. And the effect of TUBB4A overexpression on mitophagy and glioma progression was consistent with that of PINK1/Parkin agonist. In conclusion,TUBB4A is a molecular marker for predicting the prognosis of glioma patients and an effective target for inhibiting glioma progression by regulating ROS-PINK1/Parkin-mitophagy pathway.

Hovenia dulcis Thunb. monofloral honey attenuates LPS-induced inflammation and endotoxemia through the activation of the Nrf2/HO-1 axis

Monofloral honey derived from Hovenia dulcis Thunb. (HMH) is known for its antimicrobial and antioxidant properties. However, its potential to alleviate the inflammatory response has not yet been explored. The aim of this study was to investigate the anti-inflammatory and anti-endotoxemic effects of HMH. The findings showed that HMH did not exhibit toxicity to RAW 264.7 macrophages at low concentrations and suppressed the production of proinflammatory mediators, such as nitric oxide and prostaglandin E2, as well as cytokines, including tumor necrosis factor-α and interleukin-12 in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, by inhibiting NF-κB activation. Additionally, HMH prevented mortality and abnormalities in LPS-microinjected zebrafish larvae along with the inhibition of proinflammatory genes. In addition, HMH was found to reduce mitochondrial membrane potential depolarization and mitochondrial reactive oxygen species production in both LPS-stimulated RAW 264.7 macrophages and zebrafish larvae. Furthermore, HMH induced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) and promotes the nuclear translocation of Nrf2. The anti-inflammatory effects of HMH are mediated via the Nrf2-HO-1 axis, and an HO-1 inhibitor reverses HMH-induced responses. This study is the first to demonstrate the anti-inflammatory and anti-endotoxemic effects of HMH, highlighting its potential as a therapeutic.

Encapsulation of 4-oxo-N-(4-hydroxyphenyl) retinamide in human serum albumin nanoparticles promotes EZH2 degradation in preclinical neuroblastoma models.

Neuroblastoma is the most prevalent and aggressive solid tumor that develops extracranially in children between the ages of 0-14 years, which accounts for 8-10% of all childhood malignancies and ∼15% of pediatric cancer-related mortality. The polycomb repressive complex 2 (PRC2) protein, EZH2, is overexpressed in neuroblastoma and mediates histone H3 methylation at lysine 27 (K27) positions through its methyl transferase activity and is a potential epigenetic silencer of many tumor suppressor genes in cancer. Phosphorylation of EZH2 decreases its stability and leads to proteasomal degradation. The 4-oxo-N-(4-hydroxyphenyl) retinamide (4O4HPR) promotes EZH2 degradation via activation of PKC-δ, but its limited solubility and physiological instability limit its application. In the current study, the encapsulation of 4O4HPR in Human Serum Albumin Nanoparticles (HSANPs) enhanced the solubility and physiological stability of the nanoformulation, leading to improved therapeutic efficacy through G2-M cell cycle arrest, depolarization of mitochondrial membrane potential, generation of reactive oxygen species and caspase 3 mediated apoptosis activation. The molecular mechanistic approach of 4O4HPR loaded HSANPs has activated caspase 3, which further cleaves PKC-δ into two fragments wherein the cleaved fragment of PKC-δ possesses the kinase activity that phosphorylates EZH2 and decreases the protein stability leading to its further ubiquitination in SH-SY5Y cells. Co-immunoprecipitation experiments revealed the direct interaction between PKC-δ and EZH2 phosphorylation, followed by ubiquitination. Moreover, 4O4HPR loaded HSANPs demonstrated improved in vivo biodistribution, greater dispersibility, and biocompatibility and exhibited enhanced protein instability and degradation of EZH2 in the neuroblastoma xenograft mouse model.

Design, synthesis and biological evaluation of artesunate-Se derivatives as anticancer agents by inducing GPX4-mediated ferroptosis

A series of organoselenium compounds based on the hybridization of artesunate (ART) scaffolds and Se functionalities (–SeCN and –SeCF3) were synthesized. The redox properties of artesunate-SeCN and artesunate-SeCF3 derivatives were conducted by 2, 2-didiphenyl-1-picrylhydrazyl (DPPH), and the results showed that compounds 2c, 2f and 3e have a good free radical scavenging activity. Their cytotoxicity was evaluated against four types of cancer cell lines, SW480 (human colon adenocarcinoma cells), HCT116 (human colorectal adenocarcinoma cells), HepG2 (human hepatocellular carcinoma cells), MCF-7 (human breast cancer cells). The MTT results showed that compared with ART and 5-FU, compound 2c exhibited potent in vitro antiproliferative activity in SW480, HCT116, and MCF-7 cancer cell lines, and was thus chose for further antitumor mechanism investigation. The antitumor mechanism study revealed that compound 2c induced ferroptosis in HCT116 cells by inhibiting the expression of GPX4 protein, accompanying by the up-regulation of intracellular ROS levels. Mitochondria in HCT116 cells exhibit depolarization of mitochondrial membrane potential (MMP) and ultrastructural changes in morphology, which indicated that 2c resulted in mitochondrial dysfunction and ferroptosis. Moreover, 2c could increase the levels of lipid peroxidation and ferrous ion, which further confirm that compound 2c may exert its antitumor effect through ferroptosis. Overall, these results suggest that the artesunate-Se candidates could provide promising new lead derivatives for further potential anticancer drug development.

Mechanisms of mitochondrial resilience in teleostean radial glia under hypoxic stress

Radial glial cells (RGCs) are remarkable cells, essential for normal development of the vertebrate central nervous system. In teleost fishes, RGCs play a pivotal role in neurogenesis and regeneration of injured neurons and glia. RGCs also exhibit resilience to environmental stressors like hypoxia via metabolic adaptations. In this study, we assessed the physiology of RGCs following varying degrees of hypoxia, with an emphasis on reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), mitophagy, and energy metabolism. Our findings demonstrated that hypoxia significantly elevated ROS production and induced MMP depolarization in RGCs. The mitochondrial disturbances were closely associated with increased mitophagy, based on the co-localization of mitochondria and lysosomes. Key mitophagy-related genes were also up-regulated, including those of the BNIP3/NIX mediated pathway as well as the FUNDC1 mediated pathway. Such responses suggest robust cellular mechanisms are initiated to counteract mitochondrial damage due to increasing hypoxia. A significant metabolic shift from oxidative phosphorylation to glycolysis was also observed in RGCs, which may underlie an adaptive response to sustain cellular function and viability following a reduction in oxygen availability. Furthermore, hypoxia inhibited the synthesis of mitochondrial complexes subunits in RGCs, potentially related to elevated HIF-2α expression with 3 % O2. Taken together, RGCs appear to exhibit complex adaptive responses to hypoxic stress, characterized by metabolic reprogramming and the activation of mitophagy pathways to mitigate mitochondrial dysfunction.

Chidamide induces cell cycle arrest via NR4A3/P21 axis upregulation to suppress relapsed and refractory acute myeloid leukemia

(1) Currently, the survival prognosis for patients with relapsed and refractory acute myeloid leukemia (R/R AML) is extremely poor. Therefore, the exploration of novel drugs is imperative to enhance the prognosis of patients with R/R AML. The therapeutic efficacy and mechanism of Chidamide, a novel epigenetic regulatory drug, in the treatment of R/R AML remain unclear. MethodsThe mechanism of action of Chidamide has been explored in various AML cell lines through various methods such as cell apoptosis, cell cycle analysis, high-throughput transcriptome sequencing, gene silencing, and xenograft models. ResultsHere, we have discovered that chidamide potently induces apoptosis, G0/G1 phase arrest, and mitochondrial membrane potential depolarization in R/R AML cells, encompassing both primary cells and cell lines. Through RNA-seq analysis, we further revealed that chidamide epigenetically regulates the upregulation of differentiation-related pathways while suppressing those associated with cell replication and cell cycle progression. Notably, our screening identified NR4A3 as a key suppressor gene whose upregulation by chidamide leads to P21-dependent cell cycle arrest in the G0/G1 phase. ConclusionsWe have discovered a novel epigenetic regulatory mechanism of chidamide in the treatment of relapsed and refractory acute myeloid leukemia (R/R AML).

Iron Overloading Potentiates the Antitumor Activity of 5-Fluorouracil by Promoting Apoptosis and Ferroptosis in Colorectal Cancer Cells.

Resistance to 5-fluorouracil (5-FU) remains a significant challenge in colorectal cancer (CRC) treatment. Ferric ammonium citrate (FAC) is commonly used as an iron supplement due to its food-fortification properties; however, its potential role as a chemosensitizer in cancer therapy has not been studied. In this study, we explored the ability of FAC to sensitize CRC cells and increase their susceptibility to 5-FU-mediated anticancer effects. We assessed cell viability, cell cycle progression, apoptosis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) levels, ferroptosis, and iron metabolism-related protein expression using two CRC cell lines. Additionally, we conducted in silico analyses to compare iron markers in normal colon and CRC tumor tissues. Compared to controls, CRC cells pretreated with FAC and then treated with 5-FU exhibited significantly reduced growth and viability, along with increased ROS-mediated ferroptosis. Mechanistically, FAC-pretreated then 5-FU-treated CRC cells showed enhanced apoptosis, increased Bak/Bax expression, MMP depolarization, and decreased antiapoptotic protein levels (Bcl-2 and Bcl-xL). This combined treatment also led to G2/M cell cycle arrest, upregulation of p21 and p27, and downregulation of cyclin D1, c-Myc, survivin, and GPX4. Analysis of human colon tumor tissue revealed decreased expression of IRP-1, HMOX-1, and FTH1 but increased HAMP expression. In contrast, FAC-pretreated/5-FU-treated CRC cells exhibited a reverse pattern, suggesting that FAC-induced chemosensitization enhances 5-FU-mediated anticancer activity in CRC by disrupting iron homeostasis. These findings highlight the potential of iron overload as a chemosensitization strategy for improving CRC chemotherapy.

Unveiling the mechanism of hesperidin-induced LdTopI-mediated cell death pathway in protozoan parasite Leishmania donovani

Unicellular protozoan parasite Leishmania donovani is the causative agent for visceral leishmaniasis (VL) or Kala-azar, a neglected fatal parasitic disease. The conventional treatment of VL consists of therapeutic agents having several shortcomings such as toxicity, high cost, efficacy variance and increased drug resistance. Therefore, there is a desperate need to develop an effective treatment against the parasite. Previous reports suggested that flavonoids can inhibit the enzyme Leishmania donovani DNA topoisomerase I (LdTopILS). Therefore, for the first time in this present study, we divulge HSP (one of the natural sources of flavonoids), as a potent natural antileishmanial compound with efficacy in BALB/c mice at 20 mg/kg of body weight, inhibits LdTopILS at 97 % of its activity at 160 μM in preincubation condition (competitively). It binds with free enzyme and does not allow it to bind with the substrate DNA. Moreover, HSP does not stabilize DNA-topoisomerase I cleavable complex. Thus, HSP acts a catalytic topoisomerase I inhibitor, which inhibits complete activity by binding with Lys269 and Thr411 of large subunit of the enzyme. On the other hand, HSP induces the topo I-mediated programmed cell death process by the formation of cellular reactive oxygen species, resulting in depolarization of mitochondrial membrane potential, followed by fragmentation of nuclear DNA. Therefore, the present study illuminates a natural flavonoid that in future might be a promising lead for the treatment of VL.

Cuproptosis associated cytoskeletal destruction contributes to podocyte injury in chronic kidney disease.

The podocyte cytoskeleton determines the stability of podocyte structure and function, and their imbalance plays a pathogenic role in podocyte diseases. However, the underlying mechanism of podocyte cytoskeleton damage is not fully understood. Here, we investigate the specific role of cuproptosis in inducing podocyte cytoskeleton injury. In in vitro and in vivo studies, exposure to high levels of copper and adriamycin (ADR) caused significant increases in copper concentration in intracellular and renal tissue. Moreover, excessive accumulation of copper induced cuproptosis, resulting in the destruction of the podocyte cytoskeleton. However, inhibition of copper accumulation to reduce cuproptosis also significantly alleviated the damage of podocyte cytoskeleton. In addition, inhibition of cuproptosis mitigated ADR-induced mitochondrial damage as well as the production of reactive oxygen species and depolarization of mitochondrial membrane potential, and restored adenosine triphosphate (ATP) synthesis. Among the transcriptome sequencing data, the difference of CXCL5 (C-X-C motif chemokine ligand 5) was the most significant. Both high copper and ADR exposure can cause upregulation of CXCL5, and CXCL5 deletion inhibits the occurrence of cuproptosis, thereby alleviating the podocyte cytoskeleton damage. This suggests that CXCL5 may act upstream of cuproptosis that mediates podocyte cytoskeleton damage. In conclusion, cuproptosis induced by excessive copper accumulation may induce podocyte cytoskeleton damage by promoting mitochondrial dysfunction, thereby causing podocyte injury. This indicates that cuproptosis plays an important role in the pathogenesis of podocyte injury and provides a basis for seeking potential targets for the treatment of chronic kidney disease.NEW & NOTEWORTHY Cuproptosis induced by excessive copper accumulation leads to podocyte cytoskeleton damage by promoting mitochondrial dysfunction, and CXCL5 acts as an upstream signal mediating the occurrence of cuproptosis.

Activating the iNOS regulatory pathway by arginine deprivation targets energy metabolism to induce autophagy-dependent apoptosis against spinal echinococcosis

Spinal echinococcosis is one of the most overlooked zoonotic parasitic diseases worldwide. There is currently no safe and effective treatment to eradicate it, and research based on the physiological-metabolic signature of the disease is lacking. Herein, we repurposed agrimol B as a potent anti-hydatid compound and validated its pharmacological mechanism based on arginine uptake as a target through multi-omics sequencing. This herbal component suppressed energy metabolism and activated ROS aggregation by inducing mitochondrial membrane potential depolarization, which subsequently triggered autophagy-dependent apoptosis leading to parasite death. Moreover, we discovered that arginine deprivation induced metabolic changes led to a shift from ornithine to nitrogen oxide synthesis, thus boosting the iNOS enzyme-regulated dominant metabolic pathway. The excess NO targeted the mitochondrial respiratory chain complex IV to disrupt energy metabolic homeostasis and induced a downstream pathological waterfall effect to kill the hydatid. A novel metabolic regulatory mechanism targeting mitochondrial damage for arginine starvation therapy was discovered. Finally, arginine depletion was found to be superior to the anti-spinal echinococcosis effect of albendazole and accompanied by the potential for disc protection. This study unveils the role of arginine in the physiological metabolism of Echinococcus granulosus and reveals the value of targeting arginine metabolism as a potential therapy. In addition, agrimol B is proposed as a promising therapeutic strategy for spinal echinococcosis to block arginine uptake and break this parasite’s metabolic balance.

Thymoquinone, artemisinin, and thymol attenuate proliferation of lung cancer cells as Sphingosine kinase 1 inhibitors

Sphingosine-1-phosphate (S1P) formed via catalytic actions of sphingosine kinase 1 (SphK1) behaves as a pro-survival substance and activates downstream target molecules associated with various pathologies, including initiation, inflammation, and progression of cancer. Here, we aimed to investigate the SphK1 inhibitory potentials of thymoquinone (TQ), Artemisinin (AR), and Thymol (TM) for the therapeutic management of lung cancer. We implemented docking, molecular dynamics (MD) simulations, enzyme inhibition assay, and fluorescence measurement studies to estimate binding affinity and SphK1 inhibitory potential of TQ, AR, and TM. We further investigated the anti-cancer potential of these compounds on non–small cell lung cancer (NSCLC) cell lines (H1299 and A549), followed by estimation of mitochondrial ROS, mitochondrial membrane potential depolarization, and cleavage of DNA by comet assay. Enzyme activity and fluorescence binding studies suggest that TQ, AR, and TM significantly inhibit the activity of SphK1 with IC50 values of 35.52 µM, 42.81 µM, and 53.68 µM, respectively, and have an excellent binding affinity. TQ shows cytotoxic effect and anti-proliferative potentials on H1299 and A549 with an IC50 value of 27.96 µM and 54.43 µM, respectively. Detection of mitochondrial ROS and mitochondrial membrane potential depolarization shows promising TQ-induced oxidative stress on H1299 and A549 cell lines. Comet assay shows promising TQ-induced oxidative DNA damage. In conclusion, TQ, AR, and TM act as potential inhibitors for SphK1, with a strong binding affinity. In addition, the cytotoxicity of TQ is linked to oxidative stress due to mitochondrial ROS generation. Overall, our study suggests that TQ is a promising inhibitor of SphK1 targeting lung cancer therapy.

Lovastatin-Induced Mitochondrial Oxidative Stress Leads to the Release of mtDNA to Promote Apoptosis by Activating cGAS-STING Pathway in Human Colorectal Cancer Cells.

Statins are 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors widely used in the treatment of hyperlipidemia. The inhibition of HMG-CoA reductase in the mevalonate pathway leads to the suppression of cell proliferation and induction of apoptosis. The cyclic GMP-AMP synthase (cGAS) stimulator of the interferon genes (STING) signaling pathway has been suggested to not only facilitate inflammatory responses and the production of type I interferons (IFN), but also activate other cellular processes, such as apoptosis. It has not been studied, however, whether cGAS-STING activation is involved in the apoptosis induced by statin treatment in human colorectal cancer cells. In this study, we reported that lovastatin impaired mitochondrial function, including the depolarization of mitochondrial membrane potential, reduction of oxygen consumption, mitochondrial DNA (mtDNA) integrity, and mtDNA abundance in human colorectal cancer HCT116 cells. The mitochondrial dysfunction markedly induced ROS production in mitochondria, whereas the defect in mitochondria respiration or depletion of mitochondria eliminated reactive oxygen species (ROS) production. The ROS-induced oxidative DNA damage by lovastatin treatment was attenuated by mitochondrial-targeted antioxidant mitoquinone (mitoQ). Upon DNA damage, mtDNA was released into the cytosol and bound to DNA sensor cGAS, thus activating the cGAS-STING signaling pathway to trigger a type I interferon response. This effect was not activated by nuclear DNA (nuDNA) or mitochondrial RNA, as the depletion of mitochondria compromised this effect, but not the knockdown of retinoic acid-inducible gene-1/melanoma differentiation-associated protein 5 (RIG-I/MDA5) adaptor or mitochondrial antiviral signaling protein (MAVS). Moreover, lovastatin-induced apoptosis was partly dependent on the cGAS-STING signaling pathway in HCT116 cells as the knockdown of cGAS or STING expression rescued cell viability and mitigated apoptosis. Similarly, the knockdown of cGAS or STING also attenuated the antitumor effect of lovastatin in the HCT116 xenograft model in vivo. Our findings suggest that lovastatin-induced apoptosis is at least partly mediated through the cGAS-STING signaling pathway by triggering mtDNA accumulation in the cytosol in human colorectal cancer HCT116 cells.

Osthole Suppresses Cell Growth of Prostate Cancer by Disrupting Redox Homeostasis, Mitochondrial Function, and Regulation of tiRNAHisGTG.

Prostate cancer remains a significant global health concern, posing a substantial threat to men's well-being. Despite advancements in treatment modalities, the progression of prostate cancer still presents challenges, warranting further exploration of novel therapeutic strategies. In this study, osthole, a natural coumarin derivative, inhibited cell viability in cancer cells but not in the normal prostate cell line. Moreover, osthole disrupted cell cycle progression. Furthermore, osthole reduces mitochondrial respiration with mitochondrial membrane potential (ΔΨm) depolarization and reactive oxygen species (ROS) generation, indicating mitochondrial dysfunction. In particular, osthole-induced ROS generation was reduced by N-acetyl-L-cysteine (NAC) in prostate cancer. In addition, using calcium inhibitors (2-APB and ruthenium red) and endoplasmic reticulum (ER) stress inhibitor (4-PBA), we confirmed that ER stress-induced calcium overload by osthole causes mitochondrial dysfunction. Moreover, we verified that the osthole-induced upregulation of tiRNAHisGTG expression is related to mechanisms that induce permeabilization of the mitochondrial membrane and calcium accumulation. Regarding intracellular signaling, osthole inactivated the PI3K and ERK pathways while activating the expression of the P38, JNK, ER stress, and autophagy-related proteins. In conclusion, the results suggest that osthole can be used as a therapeutic or adjuvant treatment for the management of prostate cancer.