Bax-induced cytochrome C release from mitochondria is independent of the permeability transition pore but highly dependent on Mg2+ ions

Mechanism of mitochondrial oxidative phosphorylation disorder in male infertility

ABSTRACT

Male infertility has become a global concern, accounting for 20-70% of infertility. Dysfunctional spermatogenesis is the most common cause of male infertility; thus, treating abnormal spermatogenesis may improve male infertility and has attracted the attention of the medical community. Mitochondria are essential organelles that maintain cell homeostasis and normal physiological functions in various ways, such as mitochondrial oxidative phosphorylation (OXPHOS). Mitochondrial OXPHOS transmits electrons through the respiratory chain, synthesizes adenosine triphosphate (ATP), and produces reactive oxygen species (ROS). These mechanisms are vital for spermatogenesis, especially to maintain the normal function of testicular Sertoli cells and germ cells. The disruption of mitochondrial OXPHOS caused by external factors can result in inadequate cellular energy supply, oxidative stress, apoptosis, or ferroptosis, all inhibiting spermatogenesis and damaging the male reproductive system, leading to male infertility. This article summarizes the latest pathological mechanism of mitochondrial OXPHOS disorder in testicular Sertoli cells and germ cells, which disrupts spermatogenesis and results in male infertility. In addition, we also briefly outline the current treatment of spermatogenic malfunction caused by mitochondrial OXPHOS disorders. However, relevant treatments have not been fully elucidated. Therefore, targeting mitochondrial OXPHOS disorders in Sertoli cells and germ cells is a research direction worthy of attention. We believe this review will provide new and more accurate ideas for treating male infertility.

Magnesium (Mg2+): Essential Mineral for Neuronal Health: From Cellular Biochemistry to Cognitive Health and Behavior Regulation

Magnesium (Mg2+) is a crucial mineral involved in numerous cellular processes critical for neuronal health and function. This review explores the multifaceted roles of Mg2+, from its biochemical interactions at the cellular level to its impact on cognitive health and behavioral regulation. Mg2+ acts as a cofactor for over 300 enzymatic reactions, including those involved in ATP synthesis, nucleic acid stability, and neurotransmitter release. It regulates ion channels, modulates synaptic plasticity, and maintains the structural integrity of cell membranes, which are essential for proper neuronal signaling and synaptic transmission. Recent studies have highlighted the significance of Mg2+ in neuroprotection, showing its ability to attenuate oxidative stress, reduce inflammation, and mitigate excitotoxicity, thereby safeguarding neuronal health. Furthermore, Mg2+ deficiency has been linked to a range of neuropsychiatric disorders, including depression, anxiety, and cognitive decline. Supplementation with Mg2+, particularly in the form of bioavailable compounds such as Magnesium-L-Threonate (MgLT), Magnesium-Acetyl-Taurate (MgAT), and other Magnesium salts, has shown some promising results in enhancing synaptic density, improving memory function, and alleviating symptoms of mental health disorders. This review highlights significant current findings on the cellular mechanisms by which Mg2+ exerts its neuroprotective effects and evaluates clinical and preclinical evidence supporting its therapeutic potential. By elucidating the comprehensive role of Mg2+ in neuronal health, this review aims to underscore the importance of maintaining optimal Mg2+ levels for cognitive function and behavioral regulation, advocating for further research into Mg2+ supplementation as a viable intervention for neuropsychiatric and neurodegenerative conditions.

Apoptosis Regulation in Osteoarthritis and the Influence of Lipid Interactions

Osteoarthritis (OA) is one of the most common chronic diseases in human and animal joints. The joints undergo several morphological and histological changes during the development of radiographically visible osteoarthritis. The most discussed changes include synovial inflammation, the massive destruction of articular cartilage and ongoing joint destruction accompanied by massive joint pain in the later stadium. Either the increased apoptosis of chondrocytes or the insufficient apoptosis of inflammatory macrophages and synovial fibroblasts are likely to underly this process. In this review, we discuss the current state of research on the pathogenesis of OA with special regard to the involvement of apoptosis.

PW06 Triggered Fas-FADD to Induce Apoptotic Cell Death In Human Pancreatic Carcinoma MIA PaCa-2 Cells through the Activation of the Caspase-Mediated Pathway

Pancreatic cancer has higher incidence and mortality rates worldwide. PW06 [(E)-3-(9-ethyl-9H-carbazol-3-yl)-1-(2,5-dimethoxyphenyl) prop-2-en-1-one] is a carbazole derivative containing chalcone moiety which was designed for inhibiting tumorigenesis in human pancreatic cancer. This study is aimed at investigating PW06-induced anticancer effects in human pancreatic cancer MIA PaCa-2 cells in vitro. The results showed PW06 potent antiproliferative/cytotoxic activities and induced cell morphological changes in a human pancreatic cancer cell line (MIA PaCa-2), and these effects are concentration-dependent (IC₅₀ is 0.43 μM). Annexin V and DAPI staining assays indicated that PW06 induced apoptotic cell death and DNA condensation. Western blotting indicated that PW06 increased the proapoptotic proteins such as Bak and Bad but decreased the antiapoptotic protein such as Bcl-2 and Bcl-xL. Moreover, PW06 increased the active form of caspase-8, caspase-9, and caspase-3, PARP, releasing cytochrome c, AIF, and Endo G from mitochondria in MIA PaCa-2 cells. Confocal laser microscopy assay also confirmed that PW06 increased Bak and decreased Bcl-xL. Also, the cells were pretreated with inhibitors of caspase-3, caspase-8, and caspase-9 and then were treated with PW06, resulting in increased viable cell number compared to PW06 treated only. Furthermore, PW06 showed a potent binding ability with hydrophobic interactions in the core site of the Fas-Fas death domains (FADD). In conclusion, PW06 can potent binding ability to the Fas-FADD which led to antiproliferative, cytotoxic activities, and apoptosis induction accompanied by the caspase-dependent and mitochondria-dependent pathways in human pancreatic cancer MIA PaCa-2 cells.

Live-cell imaging analysis on the anti-apoptotic function of the Bcl-xL transmembrane carboxyl terminal domain

The Transmembrane Carboxyl Terminal Domain (TMD) of some Bcl-2 family proteins has been demonstrated to play a key role in modulating apoptosis. We here ustilzed live-cell fluorescence imaging to evaluate how the Bcl-xL TMD (XT) regulate apoptosis. Cell viability assay revealed that XT had strong anti-apoptotic ability similarly to the full-length Bcl-xL. Fluorescence images of living cells co-expressing CFP-XT and Bad-YFP or YFP-Bax revealed that XT recruited Bad to mitochondria but prevented Bax translocation to mitochondria, and also significantly suppressed Bad/Bax-mediated apoptosis, indicating that XT prevents the pro-apoptotic function of Bad and Bax. Fluorescence Resonance Energy Transfer (FRET) analyses determined that XT directly interacted with Bad and Bax, and deletion of XT completely eliminated the mitochondrial localization and homo-oligomerization of Bcl-xL. Fluorescence images of living cells co-expressing CFP-XT and YFP-Bax revealed that XT significantly prevented mitochondrial Bax oligomerization, resulting in cytosolic Bax distribution. Collectively, XT is necessary for the mitochondrial localization and anti-apoptotic capacity of Bcl-xL, and XT, similarly to the full-length Bcl-xL, forms homo-oligomers on mitochondria to directly interact with Bad and Bax to inhibit their apoptotic functions.

Chronic stress-induced apoptosis is mitigated by young mitochondria transplantation in the prefrontal cortex of aged rats

Objectives

Apoptosis is common and often comorbid with aging and stress-related mood disorders. Evidence suggests that fresh mitochondria could reverse age-related dysfunctions in organs, especially in the brain. Therefore, this study investigated the effect of young mitochondria administration on the apoptosis process in the prefrontal cortex (PFC) of aged rats exposed to chronic stress.

Materials and Methods

Aged (22 months old) male rats were randomly assigned into four groups: aged control (AC), aged rats treated with young mitochondria (A+M), aged rats subjected to chronic stress for four weeks (A+St), and aged rats subjected to chronic stress and treated with young mitochondria (A+St+M). A+M and A+St+M groups received a single ICV injection (10 μl) of fresh mitochondria isolated from the brain of young rats for five minutes (2 µl/min). Finally, the levels of Malondialdehyde (MDA), Cytochrome c (Cyt c), Bax, Bcl-2, and Caspase-3 expression were investigated in the PFC.

Results

Young mitochondria administration reduced neuronal apoptosis in the PFC, associated with down-regulation of MDA, Bax, and Caspase-3 and up-regulation of Bcl-2. Moreover, fresh mitochondria partially improved the chronic stress-induced mitochondrial dysfunction in aged rats, as indicated by reduced cytochrome c (Cyt c) release from the mitochondria.

Conclusion

These results suggest mitotherapy could reverse cell viability and mitochondrial dysfunction-induced apoptosis in the PFC tissue of aged rats subjected to stressful stimuli.

Chemotherapy Mediated by Biomimetic Polymeric Nanoparticles Potentiates Enhanced Tumor Immunotherapy via Amplification of Endoplasmic Reticulum Stress and Mitochondrial Dysfunction

Construction of multifunctional nanoplatforms to elevate chemotherapeutic efficacy and induce long-term antitumor immunity still remains to be an extreme challenge. Herein, the design of an advanced redox-responsive nanomedicine formulation based on phosphorus dendrimer-copper(II) complexes (1G₃ -Cu)- and toyocamycin (Toy)-loaded polymeric nanoparticles (GCT NPs) coated with cancer cell membranes (CM) are reported. The designed GCT@CM NPs with a size of 210 nm are stable under physiological conditions but are rapidly dissociated in the reductive tumor microenvironment to deplete glutathione and release drugs. The co-loading of 1G₃ -Cu and Toy within the NPs causes significant tumor cell apoptosis and immunogenic cell death through 1G₃ -Cu-induced mitochondrial dysfunction and Toy-mediated amplification of endoplasmic reticulum stress, respectively, thus effectively suppressing tumor growth, promoting dendritic cell maturation, and increasing tumor-infiltrating cytotoxic T lymphocytes. Likewise, the coated CM and the loaded 1G₃ -Cu render the GCT@CM NPs with homotypic targeting and T₁ -weighted magnetic resonance imaging of tumors, respectively. With the assistance of programmed cell death ligand 1 antibody, the GCT@CM NP-mediated chemotherapy can significantly potentiate tumor immunotherapy for effective inhibition of tumor recurrence and metastasis. The developed GCT@CM NPs hold a great potential for chemotherapy-potentiated immunotherapy of different tumor types through different mechanisms or synergies.

Identification of pyroptosis-related genes and long non-coding RNAs signatures in osteosarcoma

Osteosarcoma is a highly malignant tumor, with very high disability and fatality rates. However, the overall prognosis is not optimistic. Pyroptosis is a newly discovered cell death modality accompanied by inflammation, which is closely related to varieties of cancers. In this study, the RNA-seq data were downloaded from public databases, the differences in the expression of the pyroptosis-related genes (PRGs) were identified, and the six PRGs signature was established through the univariate and LASSO Cox analysis. The patients were grouped according to the PRGs signature, and the prognosis between the two groups was further compared. In addition, a ten pyroptosis-related lncRNAs (PRLs) prognostic signature was also constructed. Through functional analysis of the differentially expressed genes (DEGs), the immune-related pathways were found to be enriched. The Pearson correlation analysis showed a strong correlation between the pyroptosis-related biomarkers. Finally, we identified a promising biomarker, CHMP4C, which is highly expressed in osteosarcoma. Overexpression of CHMP4C promoted the proliferation, migration and invasion of the osteosarcoma cell. Our results thus provide new evidence for exploring prognostic biomarkers and therapeutic targets of osteosarcoma.

Pro-apoptotic complexes of BAX and BAK on the outer mitochondrial membrane

In multicellular organisms the regulated cell death apoptosis is critically important for both ontogeny and homeostasis. Mitochondria are indispensable for stress-induced apoptosis. The BCL-2 protein family controls mitochondrial apoptosis and initiates cell death through the pro-apoptotic activities of BAX and BAK at the outer mitochondrial membrane (OMM). Cellular survival is ensured by the retrotranslocation of mitochondrial BAX and BAK into the cytosol by anti-apoptotic BCL-2 proteins. BAX/BAK-dependent OMM permeabilization releases the mitochondrial cytochrome c (cyt c), which initiates activation of caspase-9. The caspase cascade leads to cell shrinkage, plasma membrane blebbing, chromatin condensation, and apoptotic body formation. Although it is clear that ultimately complexes of active BAX and BAK commit the cell to apoptosis, the nature of these complexes is still enigmatic. Excessive research has described a range of complexes, varying from a few molecules to several 10,000, in different systems. BAX/BAK complexes potentially form ring-like structures that could expose the inner mitochondrial membrane. It has been suggested that these pores allow the efflux of small proteins and even mitochondrial DNA. Here we summarize the current state of knowledge for mitochondrial BAX/BAK complexes and the interactions between these proteins and the membrane.

Gestational Benzo[a]pyrene Exposure Destroys F1 Ovarian Germ Cells Through Mitochondrial Apoptosis Pathway and Diminishes Surviving Oocyte Quality

Polycyclic aromatic hydrocarbons, including benzo[a]pyrene (BaP), are products of incomplete combustion. In female mouse embryos primordial germ cells proliferate before and after arriving at the gonadal ridge around embryonic (E) 10 and begin entering meiosis at E13.5. Now oocytes, they arrest in the first meiotic prophase beginning at E17.5. We previously reported dose-dependent depletion of ovarian follicles in female mice exposed to 2 or 10 mg/kg-day BaP E6.5-15.5. We hypothesized that embryonic ovaries are more sensitive to gestational BaP exposure during the mitotic developmental window, and that this exposure results in persistent oxidative stress in ovaries and oocytes of exposed F1 female offspring. We orally dosed timed-pregnant female mice with 0 or 2 mg/kg-day BaP in oil from E6.5-11.5 (mitotic window) or E12.5-17.5 (meiotic window). Cultured E13.5 ovaries were utilized to investigate the mechanism of BaP-induced germ cell death. We observed statistically significant follicle depletion and increased ovarian lipid peroxidation in F1 pubertal ovaries following BaP exposure during either prenatal window. Culture of E13.5 ovaries with BaP induced germ cell DNA damage and release of cytochrome c from the mitochondria in oocytes, confirming that BaP exposure induced apoptosis via the mitochondrial pathway. Mitochondrial membrane potential, oocyte lipid droplet (LD) volume, and mitochondrial-LD colocalization were decreased and mitochondrial superoxide levels were increased in the MII oocytes of F1 females exposed gestationally to BaP. Results demonstrate similar sensitivity to germ cell depletion and persistent oxidative stress in F1 ovaries and oocytes following gestational BaP exposure during mitotic or meiotic windows.

How Do Hexokinases Inhibit Receptor-Mediated Apoptosis?

Simple Summary

In multicellular animals, cells autonomously respond to lethal stress by inducing cell death programs. The most common regulated cell death is apoptosis. Cells protect their neighbors from damage by their cell contents or infection through this process. Apoptosis can occur as a result of intrinsic stress or induced by surface receptors, for example, by immune cells. In most cases, receptor-mediated apoptosis also requires the intrinsic signaling pathway. Intrinsic apoptosis is controlled by proteins of the B-cell lymphoma 2 (BCL-2) family. Pro-apoptotic BCL-2 proteins are inhibited by retrotranslocation from the mitochondria into the cytosol until the cell commits to apoptosis. Increasingly, discoveries show that BCL-2 proteins are regulated by proteins that are not themselves members of the BCL-2 family. Here, we discuss the selective inhibition of the link between death receptors activation and intrinsic apoptosis by hexokinases. These enzymes funnel glucose into the cellular metabolism. Independently, hexokinases retrotranslocate BCL-2 proteins and thereby protect cells from receptor-mediated apoptosis.

Abstract

The regulated cell death apoptosis enables redundant or compromised cells in ontogeny and homeostasis to remove themselves receptor-dependent after extrinsic signaling or after internal stress by BCL-2 proteins on the outer mitochondrial membrane (OMM). Mitochondrial BCL-2 proteins are also often needed for receptor-mediated signaling in apoptosis. Then, the truncated BH3-only protein BID (tBID) blocks retrotranslocation of the pro-apoptotic BCL-2 proteins BAX and BAK from the mitochondria into the cytosol. BAX and BAK in turn permeabilize the OMM. Although the BCL-2 proteins are controlled by a complex regulatory network, a specific mechanism for the inhibition of tBID remained unknown. Curiously, it was suggested that hexokinases, which channel glucose into the metabolism, have an intriguing function in the regulation of apoptosis. Recent analysis of transient hexokinase interactions with BAX revealed its participation in the inhibition of BAX and also BAK by retrotranslocation from mitochondria to the cytosol. In contrast to general apoptosis inhibition by anti-apoptotic BCL-2 proteins, hexokinase I and hexokinase 2 specifically inhibit tBID and thus the mitochondrial apoptosis pathway in response to death receptor signaling. Mitochondrial hexokinase localization and BH3 binding of cytosolic hexokinase domains are prerequisites for protection against receptor-mediated cell death, whereas glucose metabolism is not. This mechanism protects cells from apoptosis induced by cytotoxic T cells.

Apoptosis Pathways Triggered by a Potent Antiproliferative Hybrid Chalcone on Human Melanoma Cells

The World Health Organization reported that approximately 324,000 new cases of melanoma skin cancer were diagnosed worldwide in 2020. The incidence of melanoma has been increasing over the past decades. Targeting apoptotic pathways is a potential therapeutic strategy in the transition to preclinical models and clinical trials. Some naturally occurring products and synthetic derivatives are apoptosis inducers and may represent a realistic option in the fight against the disease. Thus, chalcones have received considerable attention due to their potential cytotoxicity against cancer cells. We have previously reported a chalcone containing an indole and a pyridine heterocyclic rings and an α-bromoacryloylamido radical which displays potent antiproliferative activity against several tumor cell lines. In this study, we report that this chalcone is a potent apoptotic inducer for human melanoma cell lines SK-MEL-1 and MEL-HO. Cell death was associated with mitochondrial cytochrome c release and poly(ADP-ribose) polymerase cleavage and was prevented by a non-specific caspase inhibitor. Using SK-MEL-1 as a model, we found that the mechanism of cell death involves (i) the generation of reactive oxygen species, (ii) activation of the extrinsic and intrinsic apoptotic and mitogen-activated protein kinase pathways, (iii) upregulation of TRAIL, DR4 and DR5, (iv) downregulation of p21^Cip1/WAF1 and, inhibition of the NF-κB pathway.

Characterization of oxidation of glutathione by cytochrome c

Cytochrome c is a member of the respiratory chain of the mitochondria. Non-membrane-bound (free) cytochrome c can be reduced by gluthatione as well as ascorbic acid. We investigated the effect of pH, Ca²⁺, Mg²⁺ and anionic phospholipids on the reduction of cytochrome c by glutathione.The reduction of cytochrome c by thiols was measured using photometry. Mitochondrial oxygen consumption was detected by use of oxygen electrode. Glutathione does not reduce cytochrome c at pH = 7.0 in the absence of Ca²⁺ and Mg²⁺. The reduction of cytochrome c by glutathione is inhibited by anionic lipids, especially cardiolipin. The typical conditions of apoptosis-elevated pH, Ca²⁺ level and Mg²⁺-increases the reduction of cytochrome c. Glutathione (5 mM) causes increased mitochondrial O₂ consumption at pH = 8.0, in the presence of ADP either 1 mM Mg²⁺ or 1 mM Ca²⁺. Our results suggest that membrane bound cyt c does not oxidize glutathione. Free (not membrane bound) cytochrome c can oxidize glutathione. In mitochondria, O₂ is depleted only in the presence of ADP, so the O₂ depletion observed in the presence of glutathione can be related to the respiratory chain. Decreased glutathione levels play a role in apoptosis. Therefore, membrane unbound cyt c can contribute to apoptosis by oxidation of glutathione.

Extracellular vesicles derived from radioresistant oral squamous cell carcinoma cells contribute to the acquisition of radioresistance via the miR-503-3p-BAK axis

Despite advancements in treatments, oral squamous cell carcinoma (OSCC) has not significantly improved in prognosis or survival rate primarily due to the presence of treatment-resistant OSCC. The intercellular communication between tumour cells is a molecular mechanism involved in acquiring OSCC treatment resistance. Extracellular vesicles (EVs) and encapsulated miRNAs are important mediators of intercellular communication. Here, we focused on EVs released from clinically relevant radioresistant (CRR) OSCC cells. Additionally, we evaluated the correlation between miRNA expression in the serum samples of patients who showed resistance to radiotherapy and in EVs released from CRR OSCC cells. We found that EVs released from CRR OSCC cells conferred radioresistance to radiosensitive OSCC cells via miR-503-3p contained in EVs. This miR-503-3p inhibited BAK and impaired the caspase cascade to suppress radiation-induced apoptosis. Furthermore, OSCC cells with BAK knockdown had increased radioresistance. Additionally, the expression of circulating miR-503-3p in patients with OSCC was correlated with a poor treatment response and prognosis of radiotherapy. Our results provide new insights into the relationship between EVs and the radioresistance of OSCC and suggest that the miR-503-3p-BAK axis may be a therapeutic target and that circulating miR-503-3p is a useful prognostic biomarker in the radiotherapy of OSCC.

Lysionotin induces apoptosis of hepatocellular carcinoma cells via caspase-3 mediated mitochondrial pathway

As the sixth most prevalent cancer, liver cancer has been reported as the second cause of cancer-induced deaths globally. Lysionotin, a flavonoid compound widely distributed in Lysionotus pauciflorus Maxim, has attracted considerable attention due to its multiple biological activities. The present study analyzes the anti-liver cancer effects of lysionotin in cells and mouse models. In HepG2 and SMMC-7721 cells, lysionotin significantly reduced the viability of cells, inhibited cell proliferation and migration, enhanced cell apoptosis, promoted the increase of intracellular reactive oxygen species (ROS) levels, decreased mitochondrial membrane potential (MMP), and alternated the content of apoptosis-related proteins. In HepG2-and SMMC-7721-xenograft tumor mouse models, lysionotin inhibited tumor growth, reduced the expression levels of anti-apoptotic proteins and enhanced the expression levels of pro-apoptotic proteins in tumor tissues. Additionally, the pre-treatment of Ac-DEVD-CHO, an inhibitor of caspase-3, strongly restored the low cell viability, the enhanced apoptosis rate, the dissipation of MMP caused by lysionotin exposure, as well as prevented the lysionotin-caused enhancement on expressions of apoptosis related proteins, especially cleaved poly (ADP-ribose) polymerase (PARP), Fas Ligand (FasL), cleaved caspase-3 and Bax in both HepG2 and SMMC-7721 cells. Altogether, lysionotin showed significant anti-liver cancer effects related to caspase-3 mediated mitochondrial apoptosis.

The mitochondrial permeability transition pore: an evolving concept critical for cell life and death

In this review, we summarize current knowledge of perhaps one of the most intriguing phenomena in cell biology: the mitochondrial permeability transition pore (mPTP). This phenomenon, which was initially observed as a sudden loss of inner mitochondrial membrane impermeability caused by excessive calcium, has been studied for almost 50 years, and still no definitive answer has been provided regarding its mechanisms. From its initial consideration as an in vitro artifact to the current notion that the mPTP is a phenomenon with physiological and pathological implications, a long road has been travelled. We here summarize the role of mitochondria in cytosolic calcium control and the evolving concepts regarding the mitochondrial permeability transition (mPT) and the mPTP. We show how the evolving mPTP models and mechanisms, which involve many proposed mitochondrial protein components, have arisen from methodological advances and more complex biological models. We describe how scientific progress and methodological advances have allowed milestone discoveries on mPTP regulation and composition and its recognition as a valid target for drug development and a critical component of mitochondrial biology.

Real-time surface-enhanced Raman scattering-based live cell monitoring of the changes in mitochondrial membrane potential

Obtaining molecular information on cells in real time has been a critical challenge in studying the interaction between molecules of interest and intracellular components. Fluorescence-based methods have long served as excellent tools to study such important interactions. In this paper, we introduce a Raman scattering-based method as a promising platform to achieve the real-time monitoring of subtle molecular changes occurring within cells. We found that the Raman scattering-based method enabled monitoring changes in the mitochondrial membrane potential at the single-cell level in rheumatoid arthritis synovial fibroblasts induced by tumor necrosis factor-alpha (TNF-α) protein, various chemicals (MgCl₂, FCCP, and sodium pyruvate), and a non-chemical stimulus (i.e., light). The triphenylphosphine-modified gold nanoparticles were selectively localized in the mitochondria and showed the characteristic Raman spectrum of cytochrome C and other Raman spectra of molecular components inside the cell. The surface-enhanced Raman spectrum originating from mitochondria was sensitively changed over time when mitochondrial depolarization was induced by the addition of TNF-α, or chemicals known to induce mitochondrial depolarization. The Raman-based signal changes were well matched with results of the conventional fluorescence-based analysis. However, in contrast to the conventional approach, the Raman-based method enables monitoring such changes in real time and provides detailed molecular information in terms of the interaction of molecules. Therefore, these results highlight the possibility of surface-enhanced Raman scattering-based live cell analysis for future proteomics or drug-screening applications.

Cellular and Molecular Processes in Pulmonary Hypertension

Pulmonary hypertension (PH) is a progressive lung disease characterized by persistent pulmonary vasoconstriction. Another well-recognized characteristic of PH is the muscularization of peripheral pulmonary arteries. This pulmonary vasoremodeling manifests in medial hypertrophy/hyperplasia of smooth muscle cells (SMCs) with possible neointimal formation. The underlying molecular processes for these two major vascular responses remain not fully understood. On the other hand, a series of very recent studies have shown that the increased reactive oxygen species (ROS) seems to be an important player in mediating pulmonary vasoconstriction and vasoremodeling, thereby leading to PH. Mitochondria are a primary site for ROS production in pulmonary artery (PA) SMCs, which subsequently activate NADPH oxidase to induce further ROS generation, i.e., ROS-induced ROS generation. ROS control the activity of multiple ion channels to induce intracellular Ca²⁺ release and extracellular Ca²⁺ influx (ROS-induced Ca²⁺ release and influx) to cause PH. ROS and Ca²⁺ signaling may synergistically trigger an inflammatory cascade to implicate in PH. Accordingly, this paper explores the important roles of ROS, Ca²⁺, and inflammatory signaling in the development of PH, including their reciprocal interactions, key molecules, and possible therapeutic targets.

The selective anti-proliferative and pro-apoptotic effect of A. cherimola on MDA-MB-231 breast cancer cell line

Background

Herbal medicines have been a major target for numerous studies through the past years as an alternative treatment for cancer, mainly due to their minimal effects on normal healthy cells. Annona cherimola, popularly known as Cherimoya, is an edible natural fruit rich in phytochemical components and known to possess various biological activities. Previous studies have reported the anti-cancerous effect of A. cherimola ethanolic leaf extract (AELE) on leukemia. This study aims at studying the potential anti-cancer activity of this extract in vitro in two different breast cancer cell lines, namely MDA-MB-231 and MCF-7, in addition to investigating its toxicity on normal mesenchymal stem cells.

Methods

The anti-proliferative effect of AELE was evaluated via cell viability assay. Propidium iodide staining, Cell Death Detection ELISA and flow cytometry analysis of Annexin V binding were used to assess cell cycle progression, DNA fragmentation and apoptosis induction, respectively. Protein expression was determined via Western Blot analysis to decipher the underlying apoptotic molecular mechanism induced upon AELE treatment.

Results

The anti-proliferative effect of the extract was found to be selective on the triple-negative breast cancer cell line (MDA-MB-231) in a time- and dose-dependent manner with an IC₅₀ of 390.2 μg/mL at 48 h, with no cytotoxic effects on normal murine mesenchymal stem cells. The pro-apoptotic effect was confirmed by the increase in cellular and DNA fragmentation, flipping of the phosphatidylserine moiety to the outer leaflet, and the increase in Annexin V binding. The underlying molecular mechanism revealed the involvement of the mitochondrial pathway, as shown by alterations in mitochondrial permeability and the upregulation of cytochrome c expression.

Conclusion

All the data presented in our study suggest that AELE exhibits a selective anti-proliferative and pro-apoptotic effect on the chemo-resistant MDA-MB-231 breast cancer cells, providing evidence for the anti-tumor effects of A. cherimola.

Oxidative stress, NF-κB signaling, NLRP3 inflammasome, and caspase apoptotic pathways are activated in mammary gland of ketotic Holstein cows

Ketosis is a serious metabolic disorder characterized by systemic and hepatic oxidative stress, inflammation, and apoptosis, as well as reduced milk yield. Because of the paucity of data on mammary responses during ketosis, the aim of this study was to evaluate alterations in oxidative stress, NF-κB signaling, NLRP3 inflammasome, and caspase apoptotic pathways in mammary gland of dairy cows with ketosis. Blood, mammary gland tissue, and milk samples were collected from healthy cows [Control, blood concentration of β-hydroxybutyrate (BHB) <0.6 mM, n = 10] and cows with subclinical ketosis (SCK, blood concentration of BHB >1.2 mM and <3 mM, n = 10) or clinical ketosis (CK, blood concentration of BHB >3 mM, n = 10) at median 8 d in milk (range = 6-12). Compared with Control, serum concentration of glucose was lower (3.91 vs. 2.86 or 2.12 mM) in cows with SCK or CK, whereas concentrations of fatty acids (0.25 vs. 0.57 or 1.09 mM) and BHB (0.42 vs. 1.81 or 3.85 mM) were greater. Compared with Control, the percentage of milk fat was greater in cows with SCK or CK. In contrast, the percentage of milk protein was lower in cows with SCK or CK. We detected no differences in milk lactose content across groups. Compared with Control, activities of glutathione peroxidase, superoxide dismutase, and catalase were lower in mammary gland tissue of cows with SCK or CK. In contrast, concentrations of hydrogen peroxide and malondialdehyde were greater in cows with SCK or CK. Compared with Control, mRNA abundances of TNFA, IL6, and IL1B were greater in mammary tissues of cows with SCK or CK. In addition, activity of IKKβ and the ratio of phosphorylated inhibitor of κBα to IκBα, and of phosphorylated NF-κB p65 to NF-κB p65, were also greater in mammary tissues of cows with SCK or CK. Subclinical or clinical ketosis also led to greater activity of caspase 1 and protein abundance of caspase 1, NLRP3, Bax, caspase 3, and caspase 9. In contrast, abundance of the antiapoptotic protein was lower in SCK or CK cows. The data indicate that the mammary gland of SKC or CK cows undergoes severe oxidative stress, inflammation, and cell death.

Kill one or kill the many: interplay between mitophagy and apoptosis

Mitochondria are key players of cellular metabolism, Ca²⁺ homeostasis, and apoptosis. The functionality of mitochondria is tightly regulated, and dysfunctional mitochondria are removed via mitophagy, a specialized form of autophagy that is compromised in hereditary forms of Parkinson's disease. Through mitophagy, cells are able to cope with mitochondrial stress until the damage becomes too great, which leads to the activation of pro-apoptotic BCL-2 family proteins located on the outer mitochondrial membrane. Active pro-apoptotic BCL-2 proteins facilitate the release of cytochrome c from the mitochondrial intermembrane space (IMS) into the cytosol, committing the cell to apoptosis by activating a cascade of cysteinyl-aspartate specific proteases (caspases). We are only beginning to understand how the choice between mitophagy and the activation of caspases is determined on the mitochondrial surface. Intriguingly in neurons, caspase activation also plays a non-apoptotic role in synaptic plasticity. Here we review the current knowledge on the interplay between mitophagy and caspase activation with a special focus on the central nervous system.

Perillyl Alcohol Mitigates Behavioural Changes and Limits Cell Death and Mitochondrial Changes in Unilateral 6-OHDA Lesion Model of Parkinson's Disease Through Alleviation of Oxidative Stress

In this study, we aim to assess the phytomedicinal potential of perillyl alcohol (PA), a dietary monoterpenoid, in a unilateral 6-hydroxydopamine (6-OHDA) lesion rat model of Parkinson's disease (PD). We observed that PA supplementation alleviated behavioural abnormalities such as loss of coordination, reduced rearing and motor asymmetry in lesioned animals. We also observed that PA-treated animals exhibited reduced oxidative stress, DNA fragmentation and caspase 3 activity indicating alleviation of apoptotic cell death. We found reduced mRNA levels of pro-apoptotic regulator BAX and pro-inflammatory mediators IL18 and TNFα in PA-treated animals. Further, PA treatment successfully increased mRNA and protein levels of Bcl2, mitochondrial biogenesis regulator PGC1α and tyrosine hydroxylase (TH) in lesioned animals. We observed that PA treatment blocked BAX and Drp1 translocation to mitochondria, an event often associated with the inception of apoptosis. Further, 6-OHDA exposure reduced expression of electron transport chain complexes I and IV, thereby disturbing energy metabolism. Conversely, expression levels of both complexes were upregulated with PA treatment in lesioned rats. Finally, we found that protein levels of Nrf2, the transcription factor responsible for antioxidant gene expression, were markedly reduced in cytosolic and nuclear fraction on 6-OHDA exposure, and PA increased expression of Nrf2 in both fractions. We believe that our data hints towards PA having the ability to provide cytoprotection in a hemiparkinsonian rat model through alleviation of motor deficits, oxidative stress, mitochondrial dysfunction and apoptosis.

The roles of SHANK1 in the development of colon cancer

SH3 and multiple ankyrin repeat domains protein 1 (SHANK1) belongs to a family of postsynaptic scaffolding proteins. In this study, we found that SHANK1 was abnormally high expressed in colon cancer tissues compared to normal tissues. Colon cancer patients with low SHANK1 expression had better prognosis. Furthermore, the expression of SHANK1 was knocked down in human colon cancer cell lines HCT116 and HT29 and the role of SHANK1 was investigated in colon cancer tumorigenesis. Our results showed that the knockdown of SHANK1 inhibited the survival and proliferation of both cells. The migration of these two cell lines was significantly reduced and the apoptosis was induced compared with control cells. The Bax/Bcl-2 ratio in both cell lines that SHANK1 was knocked down was increased, which is a signal that the mitochondrial apoptotic pathway was triggered. In addition, we observed that knockdown of SHANK1 reduced the expression of phosphorylated forms of AKT and mTOR. These data suggested that loss of SHANK1 inhibited viability and induced apoptosis of HCT116 and HT29 cells through the AKT/mTOR signaling pathway. Our data revealed that SHANK1 played important roles in the growth of colon cancer cells and may be used as a novel strategy for colon cancer therapy. SIGNIFICANCE OF THE STUDY: Herein, we reported that SHANK1 was abnormally high expressed in colon cancer tissues and associated with worse prognosis of patients. In addition, knockdown of SHANK1 inhibited viability and induced apoptosis in colon cancer cell lines through AKT/mTOR signaling pathways. These data suggest that SHANK1 may be a new oncogene in colon cancer. This study reveals the role of SHANK1 in addition to neuronal development and cognitive development. And it provides a new potential target for the prediction and treatment of colon cancer.

Potent Anticancer Efficacy of First-In-Class CuII and AuIII Metaled Phosphorus Dendrons with Distinct Cell Death Pathways

First-in-class Cu^II and Au^III metaled phosphorus dendrons were synthesized and showed significant antiproliferative activity against several aggressive breast cancer cell lines. The data suggest that the cytotoxicity increases with reducing length of the alkyl chains, whereas the replacement of Cu^II with Au^III considerably increases the antiproliferative activity of metaled phosphorus dendrons. Very interestingly, we found that the cell death pathway is related to the nature of the metal complexed by the plain dendrons. Cu^II metaled dendrons showed a potent caspase-independent cell death pathway, whereas Au^III metaled dendrons displayed a caspase-dependent apoptotic pathway. The complexation of plain dendrons with Au^III increased the cellular lethality versus dendrons with Cu^II and promoted the translocation of Bax into the mitochondria and the release of Cytochrome C (Cyto C).

Down-Regulated Expression of Magnesium Transporter Genes Following a High Magnesium Diet Attenuates Sciatic Nerve Crush Injury

BACKGROUND

Magnesium supplementation has potential for use in nerve regeneration. The expression of some magnesium transporter genes is reflective of the intracellular magnesium levels.

OBJECTIVE

To assess the expression of various magnesium transporter genes as they relate to neurological alterations in a sciatic nerve injury model.

METHODS

Sciatic nerve injury was induced in rats, which were then fed either basal or high magnesium diets. Magnesium concentrations and 5 magnesium transporter genes (SLC41A1, MAGT1, CNNM2, TRPM6, and TRPM7) were measured in the tissue samples.

RESULTS

The high magnesium diet attenuated cytoskeletal loss in a dose-dependent manner in isolated nerve explants. The high magnesium diet augmented nerve regeneration and led to the restoration of nerve structure, increased S-100, and neurofilaments. This increased regeneration was consistent with the improvement of neurobehavioral and electrophysiological assessment. The denervated muscle morphology was restored with the high magnesium diet, and that was also highly correlated with the increased expression of desmin and acetylcholine receptors in denervated muscle. The plasma magnesium levels were significantly elevated after the animals consumed a high magnesium diet and were reciprocally related to the down-regulation of CNNM2, MagT1, and SCL41A1 in the blood monocytes, nerves, and muscle tissues of the nerve crush injury model.

CONCLUSION

The increased plasma magnesium levels after consuming a high magnesium diet were highly correlated with the down-regulation of magnesium transporter genes in monocytes, nerves, and muscle tissues after sciatic nerve crush injury. The study findings suggest that there are beneficial effects of administering magnesium after a nerve injury.

Astaxanthin Protects PC12 Cells against Homocysteine- and Glutamate-Induced Neurotoxicity

Memory impairment has been shown to be associated with glutamate (Glu) excitotoxicity, homocysteine (Hcy) accumulation, and oxidative stress. We hypothesize that Glu and Hcy could damage neuronal cells, while astaxanthin (ATX) could be beneficial to alleviate the adverse effects. Using PC12 cell model, we showed that Glu and Hcy provoked a huge amount of reactive oxygen species (ROS) production, causing mitochondrial damage at EC₅₀ 20 and 10 mm, respectively. The mechanisms of action include: (1) increasing calcium influx; (2) producing ROS; (3) initiating lipid peroxidation; (4) causing imbalance of the Bcl-2/Bax homeostasis; and (5) activating cascade of caspases involving caspases 12 and 3. Conclusively, the damages caused by Glu and Hcy to PC12 cells can be alleviated by the potent antioxidant ATX.

Regulation of cell death in the cardiovascular system

The adult heart is a post-mitotic terminally differentiated organ; therefore, beyond development, cardiomyocyte cell death is maladaptive. Heart disease is the leading cause of death in the world and aberrant cardiomyocyte cell death is the underlying problem for most cardiovascular-related diseases and fatalities. In this chapter, we will discuss the different cell death mechanisms that engage during normal cardiac development, aging, and disease states. The most abundant loss of cardiomyocytes occurs during a myocardial infarction, when the blood supply to the heart is obstructed, and the affected myocardium succumbs to cell death. Originally, this form of cell death was considered to be unregulated; however, research from the last half a century clearly demonstrates that this form of cell death is multifaceted and employees various degrees of regulation. We will explore all of the cell death pathways that have been implicated in this disease state and the potential interplay between them. Beyond myocardial infarction, we also explore the role and mechanisms of cardiomyocyte cell death in heart failure, myocarditis, and chemotherapeutic-induced cardiotoxicity. Inhibition of cardiomyocyte cell death has extensive therapeutic potential that will increase the longevity and health of the human heart.

Predisposition to Apoptosis in Hepatocellular Carcinoma: From Mechanistic Insights to Therapeutic Strategies

Hepatocellular carcinoma (HCC) ranks among the most rapidly evolving cancers in the Western world. The majority of HCCs develop on the basis of a chronic inflammatory liver damage that predisposes liver cancer development and leads to deregulation of multiple cellular signaling pathways. The resulting dysbalance between uncontrolled proliferation and impaired predisposition to cell death with consecutive failure to clear inflammatory damage is a key driver of malignant transformation. Therefore, resistance to death signaling accompanied by metabolic changes as well as failed immunological clearance of damaged pre-neoplastic hepatocytes are considered hallmarks of hepatocarcinogenesis. Hereby, the underlying liver disease, the type of liver damage and individual predisposition to apoptosis determines the natural course of the disease as well as the therapeutic response. Here, we will review common and individual aspects of cell death pathways in hepatocarcinogenesis with a particular emphasis on regulatory networks and key molecular alterations. We will further delineate the potential of targeting cell death-related signaling as a viable therapeutic strategy to improve the outcome of HCC patients.

Response of inflammatory cells to biodegradable ultra-fine grained Mg-based composites

Ultra-fine grained biodegradable Mg-based Mg1Zn1Mn0.3 Zr - HA and Mg4Y5.5Dy0.5 Zr - 45S5 Bioglass composites have shown great medical potential. Two types of these Mg-based biomaterials subjected to different treatments were tested and as shown earlier they are biocompatible. The aim of the study is to determine how much culture media incubated with these ultra-fine trained Mg-based composites can cause inflammatory reactions and /or periodontal cell death. The incubation of composites in the medium releases metal ions into the solution. It can be assumed that this process is permanent and also occurs in the human body. The results have shown that the effect of proinflammatory IL-6 and TNF- cytokines results in the strongest production of the acute phase proteins in the first day on the Mg1Zn1Mn0.3 Zr-5 wt.% HA-1 wt. % Ag HF-treated biocomposite after immersion for 2 h in 40 % HF and then the fastest decrease in these processes on the third day. In turn, the inflammatory process induced on the Mg1Zn1Mn0.3 Zr-5 wt.% HA-1 wt. % Ag biomaterial, in BAX / BCL ratio assessment, is the strongest on the third day and maintains a significantly high level on the following day, which, at the same time, confirms its persistence and development. In addition, these results confirm the successively generated necrotic processes. Ions can induce inflammatory reactions, which in the case of the implant may take a long time, which results in the loss of the implant. Even if the material is biocompatible in rapid in-vitro tests, it can induce inflammation in the body after some time due to the release of ions. Not every treatment improves the material's properties in terms of subsequent safety.

Tracking intra- and inter-organelle signaling of mitochondria

Mitochondria are as highly specialized organelles and masters of the cellular energy metabolism in a constant and dynamic interplay with their cellular environment, providing adenosine triphosphate, buffering Ca²⁺ and fundamentally contributing to various signaling pathways. Hence, such broad field of action within eukaryotic cells requires a high level of structural and functional adaptation. Therefore, mitochondria are constantly moving and undergoing fusion and fission processes, changing their shape and their interaction with other organelles. Moreover, mitochondrial activity gets fine-tuned by intra- and interorganelle H⁺ , K⁺ , Na⁺ , and Ca²⁺ signaling. In this review, we provide an up-to-date overview on mitochondrial strategies to adapt and respond to, as well as affect, their cellular environment. We also present cutting-edge technologies used to track and investigate subcellular signaling, essential to the understanding of various physiological and pathophysiological processes.

Cannabidiol directly targets mitochondria and disturbs calcium homeostasis in acute lymphoblastic leukemia

Anticancer properties of non-psychoactive cannabinoid cannabidiol (CBD) have been demonstrated on tumors of different histogenesis. Different molecular targets for CBD were proposed, including cannabinoid receptors and some plasma membrane ion channels. Here we have shown that cell lines derived from acute lymphoblastic leukemia of T lineage (T-ALL), but not resting healthy T cells, are highly sensitive to CBD treatment. CBD effect does not depend on cannabinoid receptors or plasma membrane Ca2+-permeable channels. Instead, CBD directly targets mitochondria and alters their capacity to handle Ca2+. At lethal concentrations, CBD causes mitochondrial Ca2+ overload, stable mitochondrial transition pore formation and cell death. Our results suggest that CBD is an attractive candidate to be included into chemotherapeutic protocols for T-ALL treatment.

miR‑222 induces apoptosis in human intervertebral disc nucleus pulposus cells by targeting Bcl‑2

Intervertebral disc degeneration (IDD) is characterized by abnormal induction of apoptosis in intervertebral disc nucleus pulposus (NP) cells. Previous studies indicated that miR-222 was upregulated in patients with rheumatoid arthritis. However, the effects of miR-222 in IDD remain unclear. The present study aimed to demonstrate the role of miR-222 in NP cells. The levels of miR-222 in patients with IDD were measured by reverse transcription-quantitative PCR. Cell Counting Kit-8 and western blotting assays were used to detect cell proliferation and apoptosis-associated protein levels, respectively. In addition, luciferase reporter assays were performed to validate the predicted target genes of miR-222. miR-222 was significantly upregulated in patients with IDD. Overexpression of miR-222 inhibited cell proliferation and induced cell apoptosis. Moreover, overexpression of miR-222 resulted in an upregulation in the levels of Bax and cleaved caspase 3, and a downregulation in the levels of Bcl-2 in NP cells. The luciferase reporter assays demonstrated that Bcl-2 is a target of miR-222. Furthermore, overexpression of miR-222 increased the levels of cytochrome c, apoptotic protease activating factor-1 and cleaved caspase 9 in NP cells. Conversely, downregulation of miR-222 could promote the proliferation of NP cells. The present data demonstrated that miR-222 induced apoptosis in NP cells by directly targeting Bcl-2. Therefore, miR-222 may act as a potential therapeutic target for the treatment of IDD.

Magnesium Is a Key Player in Neuronal Maturation and Neuropathology

Magnesium (Mg) is the second most abundant cation in mammalian cells, and it is essential for numerous cellular processes including enzymatic reactions, ion channel functions, metabolic cycles, cellular signaling, and DNA/RNA stabilities. Because of the versatile and universal nature of Mg²⁺, the homeostasis of intracellular Mg²⁺ is physiologically linked to growth, proliferation, differentiation, energy metabolism, and death of cells. On the cellular and tissue levels, maintaining Mg²⁺ within optimal levels according to the biological context, such as cell types, developmental stages, extracellular environments, and pathophysiological conditions, is crucial for development, normal functions, and diseases. Hence, Mg²⁺ is pathologically involved in cancers, diabetes, and neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, and demyelination. In the research field regarding the roles and mechanisms of Mg²⁺ regulation, numerous controversies caused by its versatility and complexity still exist. As Mg²⁺, at least, plays critical roles in neuronal development, healthy normal functions, and diseases, appropriate Mg²⁺ supplementation exhibits neurotrophic effects in a majority of cases. Hence, the control of Mg²⁺ homeostasis can be a candidate for therapeutic targets in neuronal diseases. In this review, recent results regarding the roles of intracellular Mg²⁺ and its regulatory system in determining the cell phenotype, fate, and diseases in the nervous system are summarized, and an overview of the comprehensive roles of Mg²⁺ is provided.

Fisetin Inhibits Cell Proliferation through the Induction of G0/G1 Phase Arrest and Caspase-3-Mediated Apoptosis in Mouse Leukemia Cells

Fisetin, a naturally occurring flavonoid, is found in common fruits and vegetables and has been shown to induce cytotoxic effects in many human cancer cell lines. No information has shown that fisetin induced cell cycle arrest and apoptosis in mouse leukemia WEHI-3 cells. We found that fisetin decreased total viable cells through G₀/G₁ phase arrest and induced sub-G₁ phase (apoptosis). We have confirmed fisetin induced cell apoptosis by the formation of DNA fragmentation and induction of apoptotic cell death. Results indicated that fisetin induced intracellular Ca 2+ increase but decreased the ROS production and the levels of ΔΨ m in WEHI-3 cells. Fisetin increased the activities of caspase-3, -8 and -9. Cells were pre-treated with inhibitors of caspase-3, -8 and -9 and then treated with fisetin and results showed increased viable cell number when compared to fisetin treated only. Fisetin reduced expressions of cdc25a but increased p-p53, Chk1, p21 and p27 that may lead to G₀/G₁ phase arrest. Fisetin inhibited anti-apoptotic protein Bcl-2 and Bcl-xL and increased pro-apoptotic protein Bax and Bak. Furthermore, fisetin increased the protein expression of cytochrome c and AIF. Fisetin decreased cell number through G₀/G₁ phase arrest via the inhibition of cdc25c and induction of apoptosis through caspase-dependent and mitochondria-dependent pathways. Therefore, fisetin may be useful as a potential therapeutic agent for leukemia.

Novel proteomic changes in brain mitochondria provide insights into mitochondrial dysfunction in mouse models of Huntington's disease

Huntington's disease (HD) is a progressive ultimately fatal disorder caused by a glutamine-encoding CAG expansion in the huntingtin (HTT) gene that results in degeneration mainly in striatal and cerebro-cortical brain regions. Mitochondrial dysfunction is one important facet of HD pathogenesis. Here we used R6/2 and YAC128 HD mouse models of human HD, that express different HTT transgenes and have different progression rates, to identify HD brain mitochondrial proteomic signatures. Cerebral cortical mitochondrial preparations from HD and wild-type litter mate mice were compared by two-dimensional SDS-PAGE electrophoresis and MALDI-TOF/TOF mass spectrometry. Proteomic analyses inferred 17 and 12 differentially expressed proteins, respectively in 12 week R6/2 and 15 month YAC128 HD mice, compared to controls. Peroxiredoxin 3, stress-70, DJ-1, isocitrate dehydrogenase [NAD] α subunit and ATP synthase subunit D were differentially expressed in both models. Using the PANTHER (Protein ANalysis THrough Evolutionary Relationships) classification system we show that the inferred proteins are involved in oxidative stress defense, oxidative phosphorylation, the citric acid cycle, pyruvate metabolism, apoptosis, protein folding and iron metabolism. Common mitochondrial proteomic changes are significant in mouse models of middle (YAC128) and advanced (R6/2) HD despite differences in the HTT transgenes, age, genetic background and disease stage. The findings identify a proteomic signature of HD mitochondria in mouse models that includes previously unrecognized proteins.

The overexpression of Rab9 promotes tumor progression regulated by XBP1 in breast cancer

Background

Rab9 is a small GTPase that localizes to the trans-Golgi Network (TGN) and late endosomes and is involved in the recycling of mannose-6-phosphate receptors (MPRs).

Materials and methods

To determine new treatment strategies for breast cancer and to elucidate the mechanism underlying the phenomenon, we investigated the effects of Rab9 in the human breast cancer cell lines MCF7 and MDA-MB-231.

Results

We observed that knockdown of Rab9 inhibited the survival and proliferation of MCF7 and MDA-MB-231 cells, whereas Rab9 overexpression facilitated cell survival and proliferation by inducing or suppressing apoptosis. These results were further confirmed by the Bax/Bcl-2 ratio in affected MCF7 and MDA-MB-231 cells, which demonstrated whether the mitochondrial apoptotic pathway was triggered. Furthermore, the AKT/PI3K pathway is implicated in cell growth and survival and Rab9 changed the expression and phosphorylation of PI3K signaling pathway members. XBP1 is a key regulator of Rab9 and further confirmed that Rab9 play important roles in breast cancer tumorigenesis.

Conclusion

These data suggest that Rab9 is a good candidate for a novel therapeutic strategy for the treatment of breast cancer.

In vitro cytotoxicity and anticancer effects of citral nanostructured lipid carrier on MDA MBA-231 human breast cancer cells

Very recently, we postulated that the incorporation of citral into nanostructured lipid carrier (NLC-Citral) improves solubility and delivery of the citral without toxic effects in vivo. Thus, the objective of this study is to evaluate anti-cancer effects of NLC-Citral in MDA MB-231 cells in vitro through the Annexin V, cell cycle, JC-1 and fluorometric assays. Additionally, this study is aimed to effects of NLC-Citral in reducing the tumor weight and size in 4T1 induced murine breast cancer model. Results showed that NLC-Citral induced apoptosis and G2/M arrest in MDA MB-231 cells. Furthermore, a prominent anti-metastatic ability of NLC-Citral was demonstrated in vitro using scratch, migration and invasion assays. A significant reduction of migrated and invaded cells was observed in the NLC-Citral treated MDA MB-231 cells. To further evaluate the apoptotic and anti-metastatic mechanism of NLC-Citral at the molecular level, microarray-based gene expression and proteomic profiling were conducted. Based on the result obtained, NLC-Citral was found to regulate several important signaling pathways related to cancer development such as apoptosis, cell cycle, and metastasis signaling pathways. Additionally, gene expression analysis was validated through the targeted RNA sequencing and real-time polymerase chain reaction. In conclusion, the NLC-Citral inhibited the proliferation of breast cancer cells in vitro, majorly through the induction of apoptosis, anti-metastasis, anti-angiogenesis potentials, and reducing the tumor weight and size without altering the therapeutic effects of citral.

miR-600 inhibits lung cancer via downregulating the expression of METTL3

Background

Methyltransferase like 3 (METTL3) is an RNA methyltransferase implicated in mRNA biogenesis, decay, and translation control through N⁶-methyladenosine (m⁶A) modification.

Methods

To find new treatment strategies for lung cancer and to elucidate the mechanism underlying the phenomenon, we treated the human lung cancer cell lines A549 and H1299 to investigate the effect of METTL3 on lung cancer.

Results

We observed that knockdown of METTL3 inhibited the survival and proliferation of A549 and H1299 cells. The migration and proliferation of both cell lines were significantly decreased, and the apoptosis was induced in comparison with control cells. These results were further confirmed by the transfection of miRNA of METTL3 increased the Bax/Bcl-2 ratio in A549 and H1299 cells, which is a sign that mitochondrial apoptotic pathway was triggered. The PI3K/Akt pathway is implicated in cell growth and survival and we also observed that knockdown of METTL3 changed the expression and phosphorylation of proteins of PI3K signaling pathway members. Further, our results demonstrated that miR-600 inhibited the expression of METTL3 and reversed the positive effect of METTL3 on NSCLC progression, indicating an miR-600/METTL3 pathway in NSCLC.

Conclusion

These data suggested that miR-600 inhibited lung cancer via down-regulating METTL3 expression, and knockdown of METTL3 might be used as a novel strategy for lung cancer therapy.

Methotrexate-induced apoptosis in human ovarian adenocarcinoma SKOV-3 cells via ROS-mediated bax/bcl-2-cyt-c release cascading

Introduction

The communication between a substance and a cell may depend on whether the cell is normal or pathological. The disease cells and drug interaction may occasionally overcome beneficial action of the drug; subsequently, it is important to investigate the effect of the drug in both the normal and target cells. This study aimed to evaluate the methotrexate (MTX) antiproliferative effect and explore the mechanistic approach to investigate the cell death index in SKOV-3 ovarian cells during treatment with MTX.

Methods

In vitro studies of SKOV-3 cells were examined by tetrazolium assay after exposure to various concentrations of MTX. Moreover, reactive oxygen species (ROS) generation, mitochondrial membrane potential, DNA damage, and AO/EtBr staining morphological analysis of necrotic/apoptotic cells were detected; cellular impairment in mitochondria and DNA was confirmed by JC-1 mitotracker/DAPI, respectively, and cell death pathway markers; bax/bcl-2 were analyzed.

Results

A dose-dependent antiproliferative effect of MTX treatment was observed in SKOV-3 cells; the prominent inhibitory concentration was 40 µM of MTX (P<0.01). The growth inhibition rates of the cancer cells reached 24.07% in MTX. The MTX showed increase in ROS generation and mitochondrial depolarization, and DNA integrity cells collectively advocated the apoptotic cell death at higher concentration. In addition, the results of reverse transcription polymerase chain reaction also supported the apoptosis by upregulating the bax and downregulating the bcl-2 (P<0.01). Thus the MTX moderately provokes apoptosis.

Conclusion

Our findings suggest that MTX acts on SKOV-3 cancer cells by increasing intracellular ROS levels, leading to DNA damage and altering the MMP along with apoptotic gene upregulation. This mechanism may provide new therapeutic targets to improve tumor treatment.

NPS - 2143 (hydrochloride) inhibits melanoma cancer cell proliferation and induces autophagy and apoptosis

Melanoma is a common and aggressive skin cancer caused by the oncogenic transformation of melanocytes. NPS-2143 (hydrochloride) is a calcification drug that acts as an antagonist of the calcium-sensing receptor (CaSR) and consequently stimulates the release of parathyroid hormone. In the present work, we treated cells from the human melanoma cell line M14 to investigate the effects of NPS-2143 on melanoma cells and elucidate their underlying mechanisms. We observed that NPS-2143 inhibits the survival and proliferation of M14 cells and suppresses the migration and proliferation of M14 cells by inducing apoptosis. The Bax/Bcl‑2 ratio in M14 cells was enhanced by the NPS-2143 treatment, suggesting that the mitochondrial apoptotic pathway was activated. The expression and phosphorylation of proteins involved in the PI3K signaling pathway were altered by NPS-2143 treatment. Our data show that NPS-2143 impacts the viability and induces the apoptosis of melanoma M14 cells through its impact on the PI3K signaling pathway. It suggests that NPS-2143 could represent a promising candidate for melanoma treatment.

Neuro-protective role of nanocapsulated curcumin against cerebral ischemia-reperfusion induced oxidative injury

Cerebral ischemia-reperfusion (CIR) accelerates the progression of neurodegeneration by causing mitochondrial dysfunction to overproduce reactive oxygen species (ROS). Curcumin shows protective effects against CIR-induced oxidative damage. Free curcumin (FC) is effective at high doses due to its poor bioavailability. Also the blood-brain barrier (BBB) limits the passage of substances from circulation into the cerebral region. Thus, formulation of curcumin within polyethylene glycol (PEG)-ylated polylactide-co-glycolide (PLGA) nanoparticles (NC) was applied orally to aged rats to explore its role against CIR injury. Mitochondrial damage was evaluated. The levels of pro-inflammatory cytokines and components of apoptotic pathway were studied. Unlike FC, NC pre-treatment exerted better neuro-protection by ameliorating ROS-mediated oxidative damage and prevented CIR-induced neuronal apoptosis. Therefore, curcumin incorporated PEGylated PLGA nanoparticles may be used as a suitable delivery vehicle to the brain as they can increase curcumin bioavalability and the released curcumin may confer protection to the neurons against CIR-induced oxidative damage.

Toxicity of JQ1 in neuronal derivatives of human umbilical cord mesenchymal stem cells

Bromodomain and extra-terminal domain (BET) proteins regulate the transcription of many genes including c-MYC, a proto-oncogene, which is upregulated in many types of cancers. The thienodiazepine class of BET inhibitors, such as JQ1, inhibits growth of cancer cells and triggers apoptosis. However, the effects of BET inhibitors on normal cells and mesenchymal stem cells (MSCs), which are important in routine maintenance or regeneration of damaged cells and tissues, are poorly investigated. Previously, we have shown that JQ1 causes human umbilical cord MSCs to undergo cell cycle arrest and neural differentiation. In this study, we determined that JQ1 is more deleterious to neuronal derivatives (NDs) than adipogenic, chondrogenic or osteogenic derivatives of MSCs. NDs treated with JQ1 showed a significant decrease in cell proliferation, viability, and neuronal markers. JQ1 caused cell death through the intrinsic apoptotic pathway in NDs as determined by activation of Caspase 9 and increased expression of Cytochrome C. A comparative analysis showed differential action of JQ1 on MSCs and NDs. The results showed selective neuronal toxicity of JQ1 in NDs but not in the undifferentiated MSCs. These findings suggest a more careful examination of the selection and use of BET inhibitors as therapeutic agents, as they may cause unwanted damage to non-target cells and tissues.

Calcium signaling in Alzheimer's disease & therapies

Alzheimer's disease (AD) is the most common type of dementia and is characterized by the accumulation of amyloid (Aβ) plaques and neurofibrillary tangles in the brain. Much attention has been given to develop AD treatments based on the amyloid cascade hypothesis; however, none of these drugs had good efficacy at improving cognitive functions in AD patients suggesting that Aβ might not be the disease origin. Thus, there are urgent needs for the development of new therapies that target on the proximal cause of AD. Cellular calcium (Ca²⁺) signals regulate important facets of neuronal physiology. An increasing body of evidence suggests that age-related dysregulation of neuronal Ca²⁺ homeostasis may play a proximal role in the pathogenesis of AD as disrupted Ca²⁺ could induce synaptic deficits and promote the accumulation of Aβ plaques and neurofibrillary tangles. Given that Ca²⁺ disruption is ubiquitously involved in all AD pathologies, it is likely that using chemical agents or small molecules specific to Ca²⁺ channels or handling proteins on the plasma membrane and membranes of intracellular organelles to correct neuronal Ca²⁺ dysregulation could open up a new approach to AD prevention and treatment. This review summarizes current knowledge on the molecular mechanisms linking Ca²⁺ dysregulation with AD pathologies and discusses the possibility of correcting neuronal Ca²⁺ disruption as a therapeutic approach for AD.

Cold atmospheric plasma causes a calcium influx in melanoma cells triggering CAP-induced senescence

Cold atmospheric plasma (CAP) is a promising approach in anti-cancer therapy, eliminating cancer cells with high selectivity. However, the molecular mechanisms of CAP action are poorly understood. In this study, we investigated CAP effects on calcium homeostasis in melanoma cells. We observed increased cytoplasmic calcium after CAP treatment, which also occurred in the absence of extracellular calcium, indicating the majority of the calcium increase originates from intracellular stores. Application of previously CAP-exposed extracellular solutions also induced cytoplasmic calcium elevations. A substantial fraction of this effect remained when the application was delayed for one hour, indicating the chemical stability of the activating agent(s). Addition of ryanodine and cyclosporin A indicate the involvement of the endoplasmatic reticulum and the mitochondria. Inhibition of the cytoplasmic calcium elevation by the intracellular chelator BAPTA blocked CAP-induced senescence. This finding helps to understand the molecular influence and the mode of action of CAP on tumor cells.

Cerebrospinal Fluid from Patients with Sporadic Amyotrophic Lateral Sclerosis Induces Degeneration of Motor Neurons Derived from Human Embryonic Stem Cells

Disease modeling has become challenging in the context of amyotrophic lateral sclerosis (ALS), as obtaining viable spinal motor neurons from postmortem patient tissue is an unlikely possibility. Limitations in the animal models due to their phylogenetic distance from human species hamper the success of translating possible findings into therapeutic options. Accordingly, there is a need for developing humanized models as a lead towards identifying successful therapeutic possibilities. In this study, human embryonic stem cells-BJNHem20-were differentiated into motor neurons expressing HB9, Islet1, and choline acetyl transferase using retinoic acid and purmorphamine. These motor neurons discharged spontaneous action potentials with two different frequencies (< 5 and > 5 Hz), and majority of them were principal neurons firing with < 5 Hz. Exposure to cerebrospinal fluid from ALS patients for 48 h induced several degenerative changes in the motor neurons as follows: cytoplasmic changes such as beading of neurites and vacuolation; morphological alterations, viz., dilation and vacuolation of mitochondria, curled and closed Golgi architecture, dilated endoplasmic reticulum, and chromatin condensation in the nucleus; lowered activity of different mitochondrial complex enzymes; reduced expression of brain-derived neurotrophic factor; up-regulated neurofilament phosphorylation and hyperexcitability represented by increased number of spikes. All these changes along with the enhanced expression of pro-apoptotic proteins-Bax and caspase 9-culminated in the death of motor neurons.

Comparisons of cardioprotective efficacy between fibroblast growth factor 21 and dipeptidyl peptidase-4 inhibitor in prediabetic rats

AIMS

Comparative efficacy between fibroblast growth factor 21 (FGF21) and vildagliptin on metabolic regulation, cardiac mitochondrial function, heart rate variability (HRV), and left ventricular (LV) function is not known. We hypothesized that FGF21 and vildagliptin share a similar efficacy in improving these parameters in high fat diet (HFD)-induced obese-insulin resistant rats.

METHODS

Twenty-four male Wistar rats were fed with either a normal diet (ND) or a HFD for 12 weeks. Then, ND rats were received vehicle (NDV). Rats in the HFD group were divided into three subgroups to receive either vehicle (HFV), recombinant human FGF21 (rhFGF21, 0.1 mg/kg/d, ip; HFF), or vildagliptin (3 mg/kg/d, PO; HFVil) for 28 days.

RESULTS

HFV rats developed obese-insulin resistance, increased serum tumor necrosis factors alpha (TNF-α) level, impaired heart rate variability (HRV) together with cardiac mitochondrial dysfunction, and LV dysfunction. Cardiac apoptosis was markedly increased in HFV rats indicated by decreased B-cell lymphoma 2 (Bcl-2) with increased Bcl2-associated X-protein (Bax) and cleaved caspase 3 expression. Cardiac FGF21 signaling pathways were markedly decreased in HFV rats indicated by decreased phosphor-fibroblast growth factor receptors 1 (p-FGFR1), phosphor-extracellular signal-regulated protein kinases 1 (p-ERK1/2), proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and carnitine palmitoyltransferase-1 (CPT-1) expression. Although both FGF21 and vildagliptin similarly attenuated these impairments, only HFF rats had decreased body weight, visceral fat, and serum TNF-α levels.

CONCLUSIONS

FGF21 exerts better metabolic regulation and inflammation reduction than vildagliptin. However, FGF21 and vildagliptin shared a similar efficacy for cardioprotection by improving HRV and LV function.