Mitochondrial Depolarization Research Articles

Launching triple-hit chemo attack on TNBC through nanoparticle-mediated codelivery of cisplatin-chlorambucil conjugate and venetoclax.

The BRCA1 dysfunction and HR deficiency in TNBC are responsible for high effectiveness of DNA-damaging agents in TNBC treatment. Preclinical and clinical studies confirmed the effectiveness of cisplatin in TNBC treatment. Nevertheless, the clinical utility of cisplatin is inadequate due to severe systemic side effects and resistance development. Dual-action cisplatin (IV) prodrugs provide an excellent opportunity to improve anticancer activity, reduce toxicities and minimize chance of resistance development. Therefore, in this investigation we have synthesized cisplatin-chlorambucil (CP-CBL) prodrug and loaded it with venetoclax (VTX) in phenylboronic acid conjugated TPGS-lactide nanoparticles (TNPs) to achieve tumor-targeted drug delivery thereby reducing the therapeutic dose as well as increasing the efficacy of free cisplatin, chlorambucil and venetoclax. The TNPs possessed particle size of 143nm, PDI 0.186 and entrapment efficiency of 63.5% and 56.4% for VTX and CP-CBL. The TNPs followed Higuchi release kinetic model and represented biphasic release behaviour with early burst release of drug within 2h succeeded by sustained drug release till 72h. Further, the TNPs showed∼42 folds and∼19 folds reduction in the IC50 values compared to free CP. Also, higher cellular uptake and therefore greater apoptotic index was observed for the TNPs in comparison to the untargeted nanoparticles. The TNPs further showed higher ROS generating potential, enhanced mitochondrial membrane depolarization, higher intensity of nuclear condensation and highest level of caspase-3 expression. Moreover, a noteworthy decrease in the tumor volume was noticed in the mice treated with TNPs along with lower serum toxicity biomarker levels compared to the free drugs. Overall, the developed TNPs proved to be a promising and safer strategy for inducing triple-hit action in TNBC management.

Astaxanthin‐S‐Allyl Cysteine Ester Protects Pancreatic β‐Cell From Glucolipotoxicity by Suppressing Oxidative Stress, Endoplasmic Reticulum Stress and mTOR Pathway Dysregulation

ABSTRACTGlucolipotoxicity (GLT) has emerged as established mechanism in the progression of diabetes. Identifying compounds that mitigate GLT‐induced deleterious effect on β‐cells are considered important strategy to overcome diabetes. Hence, in the present study, astaxanthin‐s‐allyl cysteine (AST‐SAC) diester was studied against GLT in β‐cells. Mus musculus pancreatic β‐cell line (βTC‐tet) was treated with high glucose (25 mM; HG) and 95 μM palmitate (PA) for 24 h to induce GLT. AST‐SAC at various concentrations (5, 10, and 15 μg/ml) were treated to understand the protective effect against HG + PA exposure in β‐cells. Under HG + PA exposure conditions oxidative stress, deregulation of mTOR pathway and endoplasmic reticulum (ER) stress are witnessed. AST‐SAC treatment eased oxidative stress, mitochondrial depolarization, DNA damage, calcium overload and accumulation of autophagosome against HG + PA exposure conditions thereby protected the cell viability of β‐cells. AST‐SAC maintained the level of proteins involved in mTOR pathway under HG + PA exposure conditions. Also, AST‐SAC treatment has mitigated the increased expression of genes and proteins such as IRE1 and PERK involved in ER stress‐mediated unfolded protein response (UPR) signaling pathways. In correspondence to it, the expression of genes involved in insulin secretion was preserved by AST‐SAC. Due to these protective effects of AST‐SAC the insulin secretion was well‐maintained in β‐cells under HG + PA exposure conditions. AST‐SAC through normalizing antioxidant status and mTOR axis as well as preventing the harmful effect of ER‐stress mediated UPR pathway has promoted the β‐cell survival and insulin secretion against GLT. Simultaneously targeting oxidative stress/mTOR axis/ER stress is required to efficiently overcome GLT in β‐cells.

Ancestral retrovirus envelope protein ERVWE1 upregulates circ_0001810, a potential biomarker for schizophrenia, and induces neuronal mitochondrial dysfunction via activating AK2.

Increasingly studies highlight the crucial role of the ancestral retrovirus envelope protein ERVWE1 in the pathogenic mechanisms of schizophrenia, a severe psychiatric disorder affecting approximately 1% of the global population. Recent studies also underscore the significance of circular RNAs (circRNAs), crucial for neurogenesis and synaptogenesis, in maintaining neuronal functions. However, the precise relationship between ERVWE1 and circRNAs in the etiology of schizophrenia remains elusive. This study observed elevated levels of hsa_circ_0001810 (circ_0001810) in the blood samples of schizophrenia patients, displaying a significant positive correlation with ERVWE1 expression. Interestingly, in vivo studies demonstrated that ERVWE1 upregulated circ_0001810 in neuronal cells. Circ_0001810, acting as a competing endogenous RNA (ceRNA), bound to miR-1197 and facilitated the release of adenylate kinase 2 (AK2). The bioinformatics analysis of the schizophrenia datasets revealed increased levels of AK2 and enrichment of mitochondrial dynamics. Notably, miR-1197 was reduced in schizophrenia patients, while AK2 levels were increased. Additionally, AK2 showed positive correlations with ERVWE1 and circ_0001810. Further studies demonstrated that AK2 led to mitochondrial dysfunction, characterized by loss of intracellular ATP, mitochondrial depolarization, and disruption of mitochondrial dynamics. Our comprehensive investigation suggested that ERVWE1 influenced ATP levels, promoted mitochondrial depolarization, and disrupted mitochondrial dynamics through the circ_0001810/AK2 pathway. Circ_0001810 and AK2 were increased in schizophrenia and positively correlated with ERVWE1. Importantly, ERVWE1 triggered mitochondrial dysfunction through circ_0001810/miR-1197/AK2 pathway. Recent focus on the impact of mitochondrial dynamics on schizophrenia development had led to our discovery of a novel mechanism by which ERVWE1 contributed to the etiology of schizophrenia, particularly through mitochondrial dynamics. Moreover, these findings collectively proposed that circ_0001810 might serve as a potential blood-based biomarker for schizophrenia. Consistent with our previous theories, ERVWE1 is increasingly recognized as a promising therapeutic target for schizophrenia.

Hops bitter β-acids have antibacterial effects against sinonasal Staphylococcus aureus but also induce sinonasal cilia and mitochondrial dysfunction.

Routine prescription of antibiotics to treat chronic rhinosinusitis (CRS) exacerbations may contribute to the propagation of antibiotic resistance. Hops bitter β-acids lupulone and colupulone possess potent antibacterial activities and, as T2R1, T2R14, and/or T2R40 agonists, may improve the impaired mucociliary clearance described in CRS patients. We investigated these molecules as alternative treatments to antibiotics in CRS management based on their antibacterial and T2Rs agonists properties. Human nasal primary cells (HNECs) and RPMI2650 cells cultures were used as study models. T2Rs expression in cell culture models and human nasal tissue was assessed using immunofluorescence, quantitative PCR, and Western blot. We performed calcium imaging and cilia beat frequency experiments to investigate T2Rs activation in study models in response to lupulone and colupulone stimulations. Finally, we studied hops β-acids cytotoxicity on cells using CellEvent, crystal violet, lactate dehydrogenase assays, immunofluorescence, and transepithelial electrical resistance assays. We confirmed lupulone and colupulone potent antibacterial effect on CRS-relevant methicillin-resistant Staphylococcus aureus but found minimal impact on P. aeruginosa. We also report T2R1, T2R14 and T2R40 expression in HNECs and RPMI2650 cell cultures. Lupulone and colupulone induced an increase in cytosolic calcium that appeared dependent on T2Rs signaling. This response was accompanied by mitochondrial membrane depolarization, cellular energy stress, decreased cell proliferation, ciliostasis, and HNECs remodeling after a single exposure to lupulone at micromolar concentrations. Our data suggest that hops β-acids may not be beneficial as treatments in CRS patients and instead contribute to the disease by impairing cell health and further deteriorating the MCC.

Genetic Insights and Epidemiological Models in Understanding Primary Open Angle Glaucoma

Primary open-angle glaucoma (POAG) is a multifactorial chronic optic neuropathy with significant genetic heterogeneity. The pathogenesis of POAG involves an imbalance between the production and drainage of aqueous humor (AH). Genetic theories suggest that transgenic mice demonstrating the GLU50LYS mutation in optineurin (OPTN) experience retinal ganglion cell apoptosis, while mutant myocilin (MYOC) proteins induce endoplasmic reticulum (ER) stress, leading to an unfolded protein response (UPR) and subsequent apoptosis of trabecular meshwork cells (TMC). Furthermore, the interaction between MYOC and mitochondria in the trabecular meshwork (TM) and astrocytes may lead to mitochondrial membrane depolarization and calcium channel dysregulation, contributing to POAG. Overexpression of MYOC variants (P370L, Q368X) is also implicated, as are epigenetic modifications and signaling pathways such as histone and DNA modification. POAG has been associated with autosomal dominant inheritance, with mutations in MYOC and OPTN being prominent causative factors, although many cases involve multiple genetic loci. Currently, over 20 genetic loci have been linked to POAG, with 14 chromosomal loci (GLC1A to GLC1N) identified, 5 of which contribute to juvenile-onset open-angle glaucoma (JOAG). Of these loci, MYOC, OPTN, WD repeat domain 36 (WDR36), and neurotrophin-4 (NTF4) are the most studied causative genes. The ongoing study of molecular genetics offers potential pathways for future therapeutic advances in the treatment of POAG.

Effect of Soy Isoflavone on Prostate Cancer Cell Apoptosis Through Inhibition of STAT3, ERK, and AKT

Genistein, an isoflavone found in soybeans, exhibits antioxidant, anti-inflammatory, and anticancer properties. This study explored the molecular mechanisms behind genistein’s anticancer effects in prostate cancer DU145 cells. In this study, genistein decreased cell viability, increased annexin V-PE(+) cells, and enhanced the sub-G0/G1 peak by flow cytometric analysis. Increased reactive oxygen species increased mitochondrial depolarization indicating mitochondrial dysfunction and inhibition of ATP formation were also observed in genistein-treated DU145 cells. Genistein upregulated p53 at the mRNA and protein levels and increased caspase-3/7 activity along with the cleavage of Bax, procaspase-3, and PARP. With the increasing genistein concentrations, the percentage of cells in the sub-G0/G1 peak and G2/M phase increased, which was inhibited by treatment with the pan-caspase inhibitor Z-VAD together with 100 μM genistein, which had little toxicity to normal prostate epithelial HPrEC cells. Genistein treatment simultaneously inhibited the activation of STAT3 and other closely related oncogenic kinases such as AKT and ERK and p38 and decreased VEGF expression. Taken together, these results suggest that genistein inhibits the growth of DU145 cells and induces apoptosis by inhibiting STAT3, AKT, ERK, and p38 which provides a molecular basis for the anticancer activity of genistein and suggests its potential as a valuable therapeutic candidate for prostate cancer.

Sonodynamic Cancer Therapy by Mn(I)-tricarbonyl complexes via Ultrasound-triggered CO release and ROS generation.

A novel ferrocene conjugated Mn(I)-tricarbonyl complex viz [Mn(Fc-tpy)(CO)3Br] (Mn2) where, Fc-tpy = 4'-ferrocenyl-2,2':6',2''-terpyridine was synthesized and fully characterized along with its non-ferrocene analog [Mn(Ph-tpy)(CO)3 Br] Ph-tpy = 4'-phenyl-2,2':6',2''-terpyridine (Mn1) for ultrasound (US) activated anticancer applications. The X-ray structure of Mn2 confirmed its distorted octahedral geometry. Mn1 and Mn2, for the first time, showed US-triggered release of CO and ROS generation (1O2 and •OH) in an aqueous solution from any Mn(I)-tricarbonyl complexes, indicating its potential for synergetic CO gas therapy and sonodynamic therapy. The above-mentioned in-solution chemistry was successfully translated into in vitro cellular models. These complexes showed unprecedented US-triggered toxicity against T-cell lymphoma and human breast cancer cells (IC50 for Mn2 < 1 μM) while were minimally toxic without US or against normal spleen cells. Mn2 was ca. 12 fold more anticancer active than Mn1, indicating that the ferrocene conjugation augmented the US sensitivity. The apoptotic sonotoxicity of Mn2 was due to US-promoted mitochondrial depolarization via ROS generation and CO release. The apoptosis was triggered by caspase 3 activation. This is the first report of Mn(I)-tricarbonyl-based sonosensitizers for cancer SDT. Overall, this study, for the first time, establishes the effectiveness of 3d metal carbonyls in SDT.

Ethyl Acetate Fraction of Chestnut Honey Attenuates Scopolamine-Induced Cognitive Impairment in Mice and Glutamate-Induced Neurotoxicity in HT22 Cells

Chestnut honey has various benefits, such as antioxidative, anti-inflammatory, immunomodulatory, antibacterial, and antiviral effects. However, the effects of chestnut honey or the ethyl acetate fraction of chestnut honey (EACH) on neurodegenerative diseases and their related cognitive impairment and neurotoxicity have not yet been established. Therefore, in this study, we investigated the mitigating effect of the EACH on scopolamine (SCO)-injected cognitive decline in mice and glutamate-exposed neurotoxicity in HT22 cells. EACH administration significantly reversed SCO-induced cognitive decline in mice, as demonstrated through the Morris water maze and passive avoidance tests. The EACH treatment showed a significant alleviation effect by recovering more than 80% of the cell viability decrease induced by glutamate exposure in the HT22 neuronal cell model. Furthermore, the EACH significantly reduced reactive oxygen species accumulation, lactate dehydrogenase release, mitochondrial depolarization, and neuronal apoptosis. The EACH regulated the level of apoptosis-related proteins, induced the nuclear translocation of nuclear factor-E2-related factor 2 (Nrf-2) and the expression of related antioxidant proteins, and induced the phosphorylation of tropomyosin-related kinase receptor B (TrkB)/cAMP-calcium response element-binding protein (CREB) and the expression of brain-derived neurotrophic factor. These data indicate that the EACH can prevent neurons from oxidative damage and improve cognitive dysfunction by activating Nrf-2 and TrkB/CREB signaling pathways. Therefore, the EACH demonstrates potential therapeutic value in mitigating oxidative stress-induced neurotoxicity, cognitive decline, and related neurodegenerative diseases.

2,2'- Bipyridine Derivatives Exert Anticancer Effects by Inducing Apoptosis in Hepatocellular Carcinoma (HepG2) Cells.

To elucidate the therapeutic potential of 2,2'-bipyridine derivatives [NPS (1-6)] on hepatocellular carcinoma HepG2 cells. The effects on cell survival, colony formation, cellular and nuclear morphology, generation of reactive oxygen species (ROS), change in the integrity of mitochondrial membrane potential (MMP), and apoptosis were investigated. Additionally, docking studies were conducted to analyze and elucidate the interactions between the derivatives and AKT and BRAF proteins. NPS derivatives (1, 2, 5 and 6) significantly impaired cell viability of HepG2 cell lines at nanogram range concentrations - 72.11 ng/mL, 154.42 ng/mL, 71.78 ng/mL, and 71.43 ng/mL, while other derivatives were also effective at concentrations below 1µg/mL. These compounds reduced the colony formation capacity of HepG2 cells in a dose-dependent manner following treatment. Mechanistic studies revealed that these derivatives induce reactive oxygen species (ROS) accumulation and cause mitochondrial membrane depolarization, ultimately triggering apoptosis in HepG2 cells. In the presence of these derivatives, cells demonstrated that 75% of cells underwent apoptosis, compared to 25% in the control group. Additionally, there was a marked increase in mitochondrial depolarization (95% cells) and a threefold rise in ROS levels compared to the controls. Docking studies revealed interactions between the derivatives and the signaling proteins AKT (PDB ID: 6HHF) and BRAF (PDB ID: 8C7Y) with binding affinities ranging from -7.10 to -9.91, highlighting their pivotal role in targeting key players in hepatocellular carcinoma progression. The findings of this study underscore the therapeutic potential of these derivatives against HepG2 cells and offer valuable insights for further experimental validation of their efficacy as inhibitors targeting AKT or BRAF signaling pathways.

An ultrasound-activated piezoelectric sonosensitizer enhances mitochondrial depolarization for effective treatment of orthotopic glioma

Despite the significant advancements in piezoelectric materials for sonodynamic therapy (SDT), the suppression of orthotopic glioma remains challenging, primarily due to the unclear mechanism and the restriction of blood-brain barrier (BBB). Herein, we proposed that layered piezoelectric SrBi2Ta2O9 nanoparticles (SBTO NPs) could effectively depolarize the mitochondrial membrane potential (ΔΨm) of glioma cells under ultrasound (US) exposure. The US-induced band bending in SBTO NPs enhanced redox ability, promoting an increase in reactive oxygen species (ROS) generation. The in vitro results proved that SBTO NPs selectively accumulated in mitochondria under US and induced apoptosis in a mitochondrial depolarization manner mediated by the generation of ROS and free charges. Furthermore, SBTO NPs could cross the BBB and then accumulate in gliomas through US/microbubbles (MBs) procedure and protein-mediated transport. The therapeutic effect of piezoelectric SBTO NPs mediated SDT was proved in the orthotopic glioma mouse model. As validated by the histopathological observation and the long-term evaluation, the good biocompatibility and biosafety of SBTO NPs make it possible for deep tumor therapy, and worthy for further preclinical study. Statement of significanceEmploying piezoelectric sonosensitizers for sonodynamic therapy (SDT) has emerged as a promising strategy for cancer treatment; however, the unclear mechanism and blood-brain barrier (BBB) limit the effectiveness of SDT in glioma. Herein, we developed piezoelectric SrBi2Ta2O9 nanoparticles (SBTO NPs) with a built-in electric field for glioma treatment and explored the underlying therapeutic mechanism. Notably, SBTO NPs selectively accumulated in mitochondria under ultrasound (US) and induced apoptosis in a mitochondrial depolarization manner, which is mediated by the generation of reactive oxygen species (ROS) and free charges. In an orthotopic glioma mouse model, SBTO NPs were delivered into the glioma through US/microbubbles and transferrin-mediated transport pathways, inhibiting tumor growth. This work provides a new paradigm for the treatment of orthotopic glioma and other tumor types.

Synergistic Effect of Salinomycin With Budesonide on TNBC Regression via EMT Reversal and Autophagy Induction.

Triple-negative breast cancer (TNBC) poses a significant clinical challenge due to its aggressive nature, lack of specific therapeutic targets, and drug resistance. Chemotherapy resistance in TNBC is largely driven by the abnormal activation of epithelial-to-mesenchymal transition (EMT) and the associated cancer stem cell-like characteristics. The combination of multiple chemotherapeutic drugs has shown promise as a treatment approach for TNBC. This study evaluates the efficacy of a novel combination therapy involving the anti-inflammatory drug Budesonide and Salinomycin, which targets cancer stem cells. Co-administration of Budesonide and Salinomycin demonstrated a synergistic effect in inhibiting TNBC cell growth by activating the intrinsic apoptosis pathway. It induced a 2- to 3-fold increase in intracellular reactive oxygen species (ROS) generation and a 25%-30% rise in mitochondrial membrane depolarization. Additionally, extensive signaling studies revealed that the co-treatment specifically targeted multiple signaling nodes, limiting downstream crosstalk. The combination also enhanced autophagic activity by inhibiting the AKT/mTOR pathway and reduced cell migration and stemness by suppressing the EMT process. Therefore, the combination of Budesonide and Salinomycin offers a novel therapeutic approach for TNBC.

Biogenesis of Cytochromes c and c1 in the Electron Transport Chain of Malaria Parasites.

Plasmodium malaria parasites retain an essential mitochondrional electron transport chain (ETC) that is critical for growth within humans and mosquitoes and is a key antimalarial drug target. ETC function requires cytochromes c and c1, which are unusual among heme proteins due to their covalent binding to heme via conserved CXXCH sequence motifs. Heme attachment to these proteins in most eukaryotes requires the mitochondrial enzyme holocytochrome c synthase (HCCS) that binds heme and the apo cytochrome to facilitate the biogenesis of the mature cytochrome c or c1. Although humans encode a single bifunctional HCCS that attaches heme to both proteins, Plasmodium parasites are like yeast and encode two separate HCCS homologues thought to be specific for heme attachment to cyt c (HCCS) or cyt c1 (HCC1S). To test the function and specificity of Plasmodium falciparum HCCS and HCC1S, we used CRISPR/Cas9 to tag both genes for conditional expression. HCC1S knockdown selectively impaired cyt c1 biogenesis and caused lethal ETC dysfunction that was not reversed by the overexpression of HCCS. Knockdown of HCCS caused a more modest growth defect but strongly sensitized parasites to mitochondrial depolarization by proguanil, revealing key defects in ETC function. These results and prior heterologous studies in Escherichia coli of cyt c hemylation by P. falciparum HCCS and HCC1S strongly suggest that both homologues are essential for mitochondrial ETC function and have distinct specificities for the biogenesis of cyt c and c1, respectively, in parasites. This study lays a foundation to develop novel strategies to selectively block ETC function in malaria parasites.

Inhibitory Effect of Alnustone on Survival and Lung Metastasis of Colorectal Cancer Cells.

Alnustone (Aln) is an effective compound of Alpinia katsumadae Hayata. Aln possesses various pharmacological activities such as antibacterial, anti-inflammatory, and anti-cancer effects. However, the inhibitory effect of Aln on colorectal cancer (CRC) has not yet been identified. Thus, research was conducted to clarify whether Aln can suppress the proliferative and metastatic ability of CRC cells. A cell viability assay was performed to confirm the decrease in CRC cell viability following Aln treatment. Flow cytometry was carried out to evaluate the effects of Aln on cell cycle arrest, autophagy, and apoptosis in CRC cells. In addition, a lung metastasis animal model was used to check the inhibitory effect of Aln on the metastasis of CRC cells. Aln remarkably diminished the viability and colony-forming ability of several CRC cell lines. In addition, Aln led to a halt at the G0/G1 phase through downregulating cyclin D1-CDK4 in CRC cells. The upregulation of LC3B and p62 expression by Aln triggered autophagy of CRC cells. Moreover, Aln promoted mitochondrial depolarization, resulting in apoptosis of CRC cells. Oral administration of Aln significantly restrained the metastasized lung tumor nodules. This study demonstrated that Aln can suppress the survival and lung metastasis of CRC cells by promoting cell cycle arrest, autophagy, and apoptosis.

CIGB-300 internalizes and impairs viability of NSCLC cells lacking actionable targets by inhibiting casein kinase-2 signaling

Overall response rates in advanced Non-Small Cell Lung Cancer (NSCLC) remains low. Thus, novel molecular targets, tailored drugs and/or drug combinations are needed. Casein Kinase-2 (CK2) is a constitutively active and frequently over-expressed enzyme which fosters tumor survival, proliferation and metastasis. By using a clinical-grade and Cell Penetrating Peptide-based inhibitor coined as CIGB-300, we explore the anti-neoplastic effects caused by interruption of CK2 signaling in lung cancer cells lacking EGFR, ALK and ROS mutations. CIGB-300 penetrated and impaired viability and proliferation of Lung Adenocarcinoma (LUAD) (A549, NCI-H522) and Lung Squamous Carcinoma (LUSC) (NCI-H226 and SK-MES-1) cells in a dose-response manner. The differential activity could not be explained by overall peptide uptake or its subcellular distribution, as evidenced by flow cytometry and confocal microscopy. Upon internalization, CIGB-300 interacted with CK2 catalytic subunits (ɑ1/ɑ2) and CK2 substrates, thus impairing phosphorylation of enzyme substrates (CDC37s13, NPM1s125) and downstream proteins (RPS6s325/326). CK2 inhibition induced an early Reactive Oxygen Species (ROS) and mitochondrial membrane depolarization, which predates lung cancer cell death. Finally, intravenous injection of CIGB-300 in a cell line-based xenograft corroborated CIGB-300’s anti-tumor effects and suggested concurrent in situ reductions of CSNK2ɑ subunit and downstream RPS6s235/236 phosphorylation. Overall, CIGB-300 therapeutic hypothesis and antineoplastic effects demonstrated herein, further support the evaluation of this clinical-grade CK2 inhibitor in advanced NSCLC with limited therapeutic options.

Sodium-glucose cotransporter 2 inhibitor attenuates left ventricular dysfunction in post-myocardial infarction in rats via reducing cardiac mitochondrial impairment

Abstract Background Sodium-glucose cotransporter 2 inhibitor (SGLT2i) is a class of antidiabetic drugs that has demonstrated cardiovascular benefits in heart failure patients, regardless of diabetic status. Although current evidence regarding the role of SGLT2i in myocardial infarction (MI) is still limited, a recent randomized study reported the favorable effects of dapagliflozin on cardiometabolic outcomes in post-MI patients. Nevertheless, the evidence of the underlying mechanism of SGLT2i in post-MI is still unclear. Purpose We aimed to investigate the cardioprotective effects and cellular mechanisms of SGLT2i in post-MI rats. Methods 72 male Wistar rats were divided into two groups: the MI group, which underwent surgery involving permanent ligation of the left anterior descending coronary artery to induce MI (n=58), and the sham group, which underwent a sham operation (n=14). One-week post-surgery, echocardiography was performed. For inclusion in the MI group, only rats exhibiting anterior wall akinesia and a left ventricular ejection fraction (LVEF) &amp;lt; 50% were considered. Subsequently, MI rats were stratified into three groups to receive different interventions: 1) MI+VEH (distilled water, PO, n=13), 2) MI+DAPA (dapagliflozin, 1 mg/kg, PO, n=11), and 3) MI+ENA (enalapril, 10 mg/kg, PO, n=14). After 8 weeks of treatment, echocardiography was performed again. Then, the rats were sacrificed, and heart tissues were used to determine mitochondrial function and protein expressions. Results After 8 weeks of treatment, the MI+VEH group exhibited a decrease in LVEF compared to the sham group (Fig. 1A). The MI+VEH group was associated with cardiac mitochondrial dysfunction, as indicated by increased mitochondrial oxidative stress, mitochondrial membrane depolarization, and mitochondrial swelling, and impaired mitochondrial biogenesis, as indicated by decreasing peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) expressions (Fig. 1B-F). Treatment with dapagliflozin and enalapril effectively attenuated left ventricular (LV) systolic dysfunction, reversed mitochondrial dysfunction, and restored mitochondrial biogenesis induced by MI (Fig. 1A-F). Conclusion SGLT2i could attenuate LV dysfunction and restore mitochondrial dysfunction in post-MI rats. These findings demonstrate SGLT2i as a novel cardioprotection against post-MI complications.

A new natural product derived from cyclosorus terminans provides cardiometabolic protection against obese-induced cardiac dysfunction in rats via suppressing mitochondrial dysfunctions and apoptosis

Abstract Background The development of a novel pharmacological target for obesity has long been considered challenging in mitigating the global cardiovascular complications and mortality. Given the cytotoxic effects associated with various anti-obesity drugs, there is growing interest in exploring new natural products as potential sources for bioactive agents to treat obesity-associated diseases with minimal side effects. While Cyclosorus terminans extract has demonstrated anti-diabetic and anti-obese efficacies in adipose-derived stem cells, its cardioprotective effects in high-fat diet (HFD)-induced obese-insulin resistance rat models have never been elucidated. Purpose To examine the effects of long-term Cyclosorus terminans treatment on metabolic, cardiac, and mitochondrial functions and apoptosis in HFD-induced obese-insulin-resistant rat models Methods Male Wistar rats (n=10) were continually fed with HFD and treated with either vehicle (HFV, virgin oil for 2 ml/kg/day, p.o., n=5) or Cyclosorus terminans (HFC, 100 mg/kg/day, p.o., n=5) for 12 weeks. Rats fed a normal diet (NDV, n=5) were used as a control to confirm the development of HFD-induced obesity. The left ventricular ejection fraction (LVEF) and the ratio between early (E) and late atrial (A) ventricular filling velocity were measured using echocardiography, and the homeostatic model assessment for insulin resistance (HOMA-IR) was determined using blood serum. The cardiac tissue was processed to assess mitochondrial reactive oxygen species (ROS) levels, membrane potential (MMP) changes via red/green fluorescence intensity ratio, and apoptotic protein. Results HFV rats became obese and had impaired cardiometabolic function as shown by reducing LVEF, E/A ratio, and increasing HOMA-IR, respectively (Fig. 1A-C). These obese rats also had mitochondrial ROS overproduction, MMP depolarization (reduced red/green ratio), and apoptosis (increased Bax protein expression) (Fig. 1D-F). Treatment with Cyclosorus terminans (HFC) significantly mitigated mitochondrial dysfunction and apoptosis, resulting in cardiometabolic protection in HFD-fed rats (Fig. 1A-F). Conclusion A new natural product derived from Cyclosorus terminans effectively protected the heart against long-term HFD-induced cardiometabolic impairments by reducing mitochondrial dysfunction and apoptosis. These findings demonstrate Cyclosorus terminans as a novel cardiometabolic protection against obesity-related cardiac complications.

Graphene oxide in low concentrations can change mitochondrial potential, autophagy, and apoptosis paths in two strains of invertebrates with different life strategies

Nanoparticles, like graphene oxide (GO), are particles with unique physiochemical properties that enable their wide application in various areas of life. The effects of GO on individual cell organelles like mitochondria and the effects of interactions are worth investigating, as they can activate multiple cellular processes, such as autophagy or apoptosis. Mitochondrial injury plays an essential role in the majority of cell death routines. In the project, we investigated cell health status measured as mitochondrial inner membrane depolarization, autophagy, and apoptosis induction during long-term GO administration in food (0.02 μg g−1 and 0.2 μg g−1 of food). Two unique Acheta domesticus strains that differ in life strategy were used: wild-type and long-lived at three different life stages (larva, young adult, mature adult). The changes in mitochondrial trans-membrane potential were marked in the wild-type strain. The autophagy was lower in all GO-treated groups in both strains, and the apoptosis was lower in both strains in the mature adult crickets. Low GO concentrations treatment for the whole life, despite mitochondrial dysfunction, may lead to inhibition of autophagy and apoptosis by arresting the cell cycle for the duration of repair, and other repair tools are involved in the process of restoring homeostasis.

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.

Biogenesis of cytochromes c and c 1 in the electron transport chain of malaria parasites.

Plasmodium malaria parasites retain an essential mitochondrional electron transport chain (ETC) that is critical for growth within humans and mosquitoes and a key antimalarial drug target. ETC function requires cytochromes c and c 1 that are unusual among heme proteins due to their covalent binding to heme via conserved CXXCH sequence motifs. Heme attachment to these proteins in most eukaryotes requires the mitochondrial enzyme holocytochrome c synthase (HCCS) that binds heme and the apo cytochrome to facilitate biogenesis of the mature cytochrome c or c 1. Although humans encode a single bifunctional HCCS that attaches heme to both proteins, Plasmodium parasites are like yeast and encode two separate HCCS homologs thought to be specific for heme attachment to cyt c (HCCS) or cyt c 1 (HCC1S). To test the function and specificity of P. falciparum HCCS and HCC1S, we used CRISPR/Cas9 to tag both genes for conditional expression. HCC1S knockdown selectively impaired cyt c 1 biogenesis and caused lethal ETC dysfunction that was not reversed by over-expression of HCCS. Knockdown of HCCS caused a more modest growth defect but strongly sensitized parasites to mitochondrial depolarization by proguanil, revealing key defects in ETC function. These results and prior heterologous studies in E. coli of cyt c hemylation by P. falciparum HCCS and HCC1S strongly suggest that both homologs are essential for mitochondrial ETC function and have distinct specificities for biogenesis of cyt c and c 1, respectively, in parasites. This study lays a foundation to develop novel strategies to selectively block ETC function in malaria parasites.

Differential Cytoprotective Effect of Resveratrol and Its Derivatives: Focus on Antioxidant and Autophagy-Inducing Effects

Numerous beneficial effects of resveratrol were reported; however, its pharmacological profile is contradictious. Previously, we have demonstrated that resveratrol has a dose-dependent cytoprotective effect and the essential role of autophagy induction was demonstrated. Resveratrol suffers from unfavorable pharmacokinetics, hindering its clinical use. Our aim was to study the cytoprotective effect of resveratrol derivatives to better understand structure–activity relationships that may facilitate the development of compounds with better druglike characteristics. Serum-deprivation-induced caspase activation, free radical generation, mitochondrial membrane depolarization and autophagy were detected in the presence of resveratrol analogs with different oxidation states on mouse embryonal fibroblasts. Distinct cytoprotective mechanisms of the examined compounds were revealed. Monomethyl resveratrol had similar potency to resveratrol (EC50: 85.3 vs. 84.2 μM); however, autophagy induction was not essential for its cytoprotective effect. Oxyresveratrol was found to be a strong antioxidant that can induce direct cytoprotection rather than autophagy. Trimethyl-resveratrol, lacking free hydroxyl groups, induced damage that was too significant and hardly compensated by the activation of cytoprotective machineries, and caspase activation was reduced by only 24.5%. Based on our results, methylation of resveratrol reduces its antioxidant activity, while autophagy induction can still contribute to its cytoprotective effect. The introduction of an additional hydroxyl group, however, augments the antioxidant properties, inducing cytoprotection without autophagy induction.