The role of mitochondria in apoptosis*

Time-resolved electromechanical and conductive behavior of nanostructured bilayers tethered to the surface of the electrode with incorporated channel proteins and peptides

The influence of incorporation of mitochondrial inner membrane potassium channel, and channel-forming peptide - Gramicidin on the ion transport and electromechanical properties of model lipid membranes tethered to gold electrode was electrochemically investigated by chronoamperometric and impedance spectroscopy techniques. In the case of the potassium channel the ion transport properties were modulated with channel-specific inhibitor - ATP-Mg2+ complex, whereas in the case of gramicidin peptide - by replacing potassium with sodium ions. The observed two exponential current-time responses of the systems studied were interpreted in terms of ion penetration and electrostriction of tethered lipid bilayer membrane, and conclusions supported with the experiments on alkanethiol self-assembled monolayers of different alkanethiol chain lengths deposited on gold.

Polyamine-modified naphthalimide derivative 9C inhibits colorectal cancer through ROS-mediated ER stress, migration and invasion

Mounting evidence over the past decades has demonstrated the therapeutic potential of targeting endoplasmic reticulum (ER) stress signaling in cancer. Naphthalimdes exert their anti-cancer activities in a variety of ways. However, the effects of naphthalimides on ER stress are rarely reported. In this study, based on RNA-sequencing analysis, we observed that 9C, a naphthalimide derivative, could trigger ER stress to activate death receptor signaling and autophagy. Pretreatment of ER stress inhibitor, such as salubrinal, and autophagy inhibitor, such as 3-methyladenine (3-MA), partially reversed 9C-induced inhibition of cell growth. Furthermore, our results unveiled a reactive oxygen species (ROS)-dependent inhibitory effect of 9C. In addition, 9C inhibited colorectal cancer (CRC) cells migration and invasion. Removal of ROS using N-acetyl-L-cysteine (NAC) attenuated the expression of ATF4, CHOP, death receptors, E-cadherin, and the apoptosis and autophagy related proteins. Taken together, our results suggested that ROS-mediated ER stress, migration, and invasion is responsible for the therapeutic potential of naphthalimides including 9C in CRC.

Ketorolac disturbs proteasome functions and induces mitochondrial abnormality-associated apoptosis

Non-steroidal anti-inflammatory drugs (NSAIDs) are recommended to treat moderate-to-severe pain. Previous studies suggest that NSAIDs can suppress cellular proliferation and elevate apoptosis in different cancer cells. Ketorolac is an NSAID and can reduce the cancer cells' viability. However, molecular mechanisms by which Ketorolac can induce apoptosis and be helpful as an anti-tumor agent against carcinogenesis are unclear. Here, we observed treatment with Ketorolac disturbs proteasome functions, which induces aggregation of aberrant ubiquitinated proteins. Ketorolac exposure also induced the aggregation of expanded polyglutamine proteins, results cellular proteostasis disturbance. We found that the treatment of Ketorolac aggravates the accumulation of various cell cycle-linked proteins, which results in pro-apoptotic induction in cells. Ketorolac-mediated proteasome disturbance leads to mitochondrial abnormalities. Finally, we have observed that Ketorolac treatment depolarized mitochondrial membrane potential, released cytochrome c into cytoplasm, and induced apoptosis in cells, which could be due to proteasome functional depletion. Perhaps more in-depth research is required to understand the details of NSAID-based anti-proliferative molecular mechanisms that can elevate apoptosis in cancer cells and generate anti-tumor potential with the combination of putative cancer drugs.

Point of No Return-What Is the Threshold of Mitochondria With Permeability Transition in Cells to Trigger Cell Death

Programmed cell death (apoptosis) is essential part of the process of tissue regeneration that also plays role in the mechanism of pathology. The phenomenon of fast and transient permeability of mitochondrial membranes by various triggers, known as permeability transition pore (mPTP) leads to the release of proapoptotic proteins and acts as an initial step in initiation of apoptosis. However, a role for mPTP was also suggested for physiology and it is unclear if there is a threshold in number of mitochondria with mPTP which induces cell death and how this mechanism is regulated in different tissues. Using simultaneous measurements of mitochondrial membrane potential and a fluorescent marker for caspase-3 activation we studied the number of mitochondria with calcium-induced mPTP opening necessary for induction of apoptosis in rat primary cortical neurons, astrocytes, fibroblasts, and cancer (BT-474) cells. The induction of apoptosis was correlated with 80%-90% mitochondrial signal loss in neural cells but only 35% in fibroblasts, and in BT-474 cancer cells over 90% of mitochondria opens mPTP before apoptosis becomes obvious. The number of mitochondria with mPTP which induce cell death did not correlate with total expression levels of proapoptotic proteins but was consistent with the Bax/Bcl-2 ratio in these cells. Calcium-induced mPTP opening increased levels of necrosis which was higher in fibroblasts compared to neurons, astrocytes and BT-474 cells. Thus, different tissues require specific numbers of mitochondria with PTP opening to induce apoptosis and it correlates to the proapoptotic/antiapoptotic proteins expression ratio in them.

Deafness-associated mitochondrial 12S rRNA mutation reshapes mitochondrial and cellular homeostasis

Human mitochondrial 12S ribosomal RNA (rRNA) 1555A>G mutation has been associated with aminoglycoside-induced and nonsyndromic deafness in many families worldwide. Our previous investigation revealed that the m.1555A>G mutation impaired mitochondrial translation and oxidative phosphorylation (OXPHOS). However, the mechanisms by which mitochondrial dysfunctions induced by m.1555A>G mutation regulate intracellular signaling for mitochondrial and cellular integrity remain poorly understood. Here, we demonstrated that the m.1555A>G mutation downregulated the expression of nuclear-encoded subunits of complexes I and IV but upregulated the expression of assemble factors for OXPHOS complexes, using cybrids derived from one hearing-impaired Chinese subject bearing the m.1555A>G mutation and from one hearing normal control lacking the mutation. These alterations resulted in the aberrant assembly, instability and reduced activities of respiratory chain enzyme complexes I, IV and V, rate of oxygen consumption, and diminished ATP production. Furthermore, the mutant cell lines carrying the m.1555A>G mutation exhibited decreased membrane potential and increased the production of reactive oxygen species. The aberrant assembly and biogenesis of OXPHOS impacted mitochondrial quality controls, including the imbalance of mitochondrial dynamics via increasing fission with abnormal mitochondrial morphology and impaired mitophagy. Strikingly, the cells bearing the m.1555A>G mutation revealed the upregulation of both ubiquitin-dependent and independent mitophagy pathways, evidenced by increasing the levels of Parkin, Pink, BNIP3L and NIX. The m.1555A>G mutation-induced deficiencies ameliorate the cell homeostasis via elevating the autophagy process and upregulating apoptotic pathways. Our findings provide new insights into pathophysiology of mitochondrial deafness arising from reshaping mitochondrial and cellular homeostasis due to 12S rRNA 1555A>G mutation.

Tri-o-tolyl phosphate impedes implantation: Malfunction of mitochondria and disruption of calcium homeostasis through MAPK and AKT signaling cascades

Tri-o-tolyl phosphate (TOTP), a flame retardant containing aryl compounds, is widely used in human living environments owing to its several applications. However, Due to the overuse of TOTP, its residue has been identified in various environments and non-targeted organisms, including humans. Although extensive research is being conducted to address the toxicity of this substance, its potential reproductive toxicity in females has not been sufficiently studied. In this study, human HTR-8/SVneo and JEG-3 trophoblasts were used to investigate the effects of TOTP on implantation. Results showed that TOTP decreased cell viability and inhibited cell proliferation by triggering cell cycle arrest. It also induced apoptosis and mitochondrial dysfunction, disrupted calcium homeostasis, increased the influx of calcium ions into the mitochondria, and disturbed cell aggregation and migration. Moreover, the MAPK and AKT cell signaling pathways were altered, and crosstalk between these pathways were distinguished. Thus, inhibitors of the MAPK and AKT pathways exhibited potential for managing the toxicity of TOTP. Overall, this study demonstrated the reproductive toxicity of TOTP in human females and elucidated the underlying mechanisms. Our results highlighted the potential risks associated with TOTP.

Mitochondrial-targeted liposome-based drug delivery - therapeutic potential and challenges

Liposomes, as nanocarriers for therapeutics, are a prominent focus in translational medicine. Given their biocompatibility, liposomes are suitable drug delivery systems rendering highly efficient therapeutic outcomes with minimal off-site toxicity. In different scenarios of human disease, it is essential not only to maintain therapeutic drug levels but also to target them to the appropriate intracellular compartment. Mitochondria regulate cellular signalling, calcium balance, and energy production, playing a crucial role in various human diseases. The notion of focusing on mitochondria for targeted drug delivery was proposed several decades ago, yet the practical application of this idea and its translation to clinical use is still in development. Mitochondrial-targeted liposomes offer an alternative to standard drug delivery systems, potentially reducing off-target interactions, side effects, and drug dosage or frequency. To advance this field, it is imperative to integrate various disciplines such as efficient chemical design, pharmacology, pharmaceutics, and cell biology. This review summarises scientific advances in the design, development and characterisation of novel liposome-based drug delivery systems targeting the mitochondria while revisiting their translational potential.

Cytotoxic effects of the standardized extract from Curcuma aromatica Salisb. rhizomes via induction of mitochondria-mediated caspase-dependent apoptotic pathway and p21-mediated G0/G1 cell cycle arrest on human gastric cancer AGS cells

Curcuma aromatica Salisb. (C. aromatica) is one of the traditional herbs used to treat microbial infection, skin eruption, coronary heart disease, and other diseases, including cancer. However, the inhibitory effects and underlying mechanisms of action of C. aromatica on gastric cancer cells have not yet been fully elucidated. Our study aimed to examine the possible molecular mechanisms underlying the cytotoxic effects attributed to C. aromatica rhizome standardized extract against gastric cancer cells. The components of two major active compounds in C. aromatica rhizome extract were quantitatively analyzed using a simple and validated HPLC method. Cytotoxicity was determined in different gastric cancer and non-cancer cell lines. The biological activities of the extract targeting apoptosis and cell cycle-related genes on gastric cancer AGS cells were also investigated to elucidate the mechanisms relating to the anti-proliferative effect of C. aromatica rhizomes. The two major active compounds curdione and germacrone, in the C. aromatica extract were standardized to 0.64% and 1.12% w/w, respectively. The standardized extract (CAE) exerted cytotoxic effects on various cancer cells, whereas minimal effects at equivalent doses were noted for normal cells. CAE concentration-dependently suppressed growth of gastric cancer AGS cells via induction of apoptosis. Further studies revealed that CAE treatment disrupted mitochondrial membrane potential (ΔΨm), increased Bax/Bcl-2 ratio, and cytochrome c release, resulting in activation of caspase-9/-3 and subsequent cleavage of PARP. Further, the inhibitory effects of caspase-9/-3 expression by a synthetic pan-caspase inhibitor partially protected cells against apoptosis following CAE treatment. In addition, CAE significantly promoted cell death in AGS cells via an accumulation of cells in the G0/G1 phase. This effect was associated with upregulation of the CDK inhibitor p21 and downregulation of cyclin D1, cyclin E, CDK4, and CDK2 expression. Our data indicated that CAE exerted anti-proliferative activity by activating the mitochondria-mediated caspase-dependent apoptotic pathway and arresting the p21-mediated G0/G1 cell cycle on human gastric cancer AGS cells.

Progress in the discovery and development of anticancer agents from marine cyanobacteria

Covering 2010-April 2024There have been tremendous new discoveries and developments since 2010 in anticancer research based on marine cyanobacteria. Marine cyanobacteria are prolific sources of anticancer natural products, including the tubulin agents dolastatins 10 and 15 which were originally isolated from a mollusk that feeds on cyanobacteria. Decades of research have culminated in the approval of six antibody-drug conjugates (ADCs) and many ongoing clinical trials. Antibody conjugation has been enabling for several natural products, particularly cyanobacterial cytotoxins. Targeting tubulin dynamics has been a major strategy, leading to the discovery of the gatorbulin scaffold, acting on a new pharmacological site. Cyanobacterial compounds with different mechanisms of action (MOA), targeting novel or validated targets in a range of organelles, also show promise as anticancer agents. Important advances include the development of compounds with novel MOA, including apratoxin and coibamide A analogues, modulating cotranslational translocation at the level of Sec61 in the endoplasmic reticulum, largazole and santacruzamate A targeting class I histone deacetylases, and proteasome inhibitors based on carmaphycins, resembling the approved drug carfilzomib. The pipeline extends with SERCA inhibitors, mitochondrial cytotoxins and membrane-targeting agents, which have not yet advanced clinically since the biology is less understood and selectivity concerns remain to be addressed. In addition, efforts have also focused on the identification of chemosensitizing and antimetastatic agents. The review covers the state of current knowledge of marine cyanobacteria as anticancer agents with a focus on the mechanism, target identification and potential for drug development. We highlight the importance of solving the supply problem through chemical synthesis as well as illuminating the biological activity and in-depth mechanistic studies to increase the value of cyanobacterial natural products to catalyze their development.

Discovery and optimization of anthraquinone derivatives containing substituted bisbenzyloxy groups as a novel scaffold damaged endoplasmic reticulum and against hepatocellular carcinoma cells

This paper reports the antitumor activity and possible mechanism of anthraquinone derivatives containing substituted bisbenzyloxy groups. Series of anthraquinone derivatives containing substituted bisbenzyloxy groups were designed and synthesized by etherification and esterification. The antitumor activities of the synthesized substituted bisbenzyloxy anthraquinone derivatives on liver cancer cell Huh7, triple negative breast cancer cell line MDA-MB-231 and lung cancer cell A549 were in the order of methoxy substitution > methyl substitution > chloral substitution. Among these, the Compound KA-MO-g showed strong antitumor activity, especially against liver cancer Huh7 cells. Further studies on the antitumor mechanism showed that the Compound KA-MO-g simultaneously activated three pathways of endoplasmic reticulum stress (ERS), also caused impairment of endoplasmic reticulum (ER) functions, such as glycoprotein synthesis and disulfide bond formation are impeded and caused calcium overload, then increased mitochondrial ROS, damaged of mitochondria, changed of apoptosis-related protein levels, activated Caspase 3, induced the apoptosis of Huh7 cells. Because KA-MO-g showed strong antitumor activity, it is expected to be a new candidate drug for treating liver cancer and is worth further study.

USP14 inhibition enhances Parkin-independent mitophagy in iNeurons

Loss of proteostasis is well documented during physiological aging and depends on the progressive decline in the activity of two major degradative mechanisms: the ubiquitin-proteasome system (UPS) and the autophagy-lysosomal pathway. This decline in proteostasis is exacerbated in age-associated neurodegenerative diseases, such as Parkinson's Disease (PD). In PD, patients develop an accumulation of aggregated proteins and dysfunctional mitochondria, which leads to ROS production, neuroinflammation and neurodegeneration. We recently reported that inhibition of the deubiquitinating enzyme USP14, which is known to enhance both the UPS and autophagy, increases lifespan and rescues the pathological phenotype of two Drosophila models of PD. Studies on the effects of USP14 inhibition in mammalian neurons have not yet been conducted. To close this gap, we exploited iNeurons differentiated from human embryonic stem cells (hESCs), and investigated the effect of inhibiting USP14 in these cultured neurons. Quantitative global proteomics analysis performed following genetic ablation or pharmacological inhibition of USP14 demonstrated that USP14 loss of function specifically promotes mitochondrial autophagy in iNeurons. Biochemical and imaging data also showed that USP14 inhibition enhances mitophagy. The mitophagic effect of USP14 inhibition proved to be PINK1/Parkin- independent, instead relying on expression of the mitochondrial E3 Ubiquitin Ligase MITOL/MARCH5. Notably, USP14 inhibition normalized the mitochondrial defects of Parkin KO human neurons.

Cannabidiol mitigates methotrexate-induced hepatic injury via SIRT-1/p53 signaling and mitochondrial pathways: reduces oxidative stress and inflammation

Methotrexate (MTX), a widely used chemotherapeutic agent, often induces hepatotoxicity, limiting its clinical utility. Cannabidiol (CBD), derived from hemp, possesses antioxidant, anti-inflammatory, and antiapoptotic properties. This study aims to investigate CBD's protective effects against MTX-induced liver injury and elucidate the underlying mechanisms. Thirty-two female Wistar Albino rats were divided into four groups: control, MTX (20 mg/kg intraperitoneally [i.p.] once), MTX+CBD (20 mg/kg i.p. once + 5 mg/kg i.p. for seven days), and CBD (5 mg/kg, i.p. for seven days). Biochemical analyses of serum and liver tissues were performed to assess oxidative stress markers (total oxidant status, total antioxidant status, oxidative stress index), liver function tests (AST, ALT), and antioxidant enzyme activities (glutathione peroxidase, superoxide dismutase). Histopathological and immunohistochemical examinations were conducted to evaluate liver tissue damage and TNF-α expression. Genetic analyses were performed to measure the expression levels of SIRT-1, p53, Bcl-2, and Bax genes using RT-qPCR. MTX administration increased oxidative stress markers, liver enzymes, TNF-α, p53, and Bax levels while decreasing antioxidant defenses and SIRT-1 expression. CBD administration reversed these alterations effectively. CBD mitigated MTX-induced hepatotoxicity by reducing oxidative stress, inflammation, and apoptosis. It activates antioxidant defenses via SIRT-1 upregulation, suppresses inflammation by reducing TNF-α, and prevents apoptosis by modulating p53, Bcl-2, and Bax gene expressions. These findings suggest CBD could be a promising therapeutic agent for chemotherapy-induced liver damage. Further research is warranted to explore additional pathways and broader molecular mechanisms.

Arginyltransferase1 drives a mitochondria-dependent program to induce cell death

Cell death regulation is essential for stress adaptation and/or signal response. Past studies have shown that eukaryotic cell death is mediated by an evolutionarily conserved enzyme, arginyltransferase1 (Ate1). The downregulation of Ate1, as seen in many types of cancer, prominently increases cellular tolerance to a variety of stressing conditions. Conversely, in yeast and mammalian cells, Ate1 is elevated under acute oxidative stress conditions and this change appears to be essential for triggering cell death. However, studies of Ate1 were conventionally focused on its function in inducing protein degradation via the N-end rule pathway in the cytosol, leading to an incomplete understanding of the role of Ate1 in cell death. Our recent investigation shows that Ate1 dually exists in the cytosol and mitochondria, the latter of which has an established role in cell death initiation. Here, by using budding yeast as a model organism, we found that mitochondrial translocation of Ate1 is promoted by the presence of oxidative stressors and is essential for inducing cell death with characteristics of apoptosis. Also, we found that Ate1-induced cell death is dependent on the formation of the mitochondrial permeability pore and at least partly dependent on the action of mitochondria-contained factors including the apoptosis-inducing factor, but is not directly dependent on mitochondrial electron transport chain activity or its derived reactive oxygen species (ROS). Furthermore, our evidence suggests that, contrary to widespread assumptions, the cytosolic protein degradation pathways including ubiquitin-proteasome, autophagy, or endoplasmic reticulum (ER) stress response has little or negligible impacts on Ate1-induced cell death. We conclude that Ate1 controls the mitochondria-dependent cell death pathway.

Effect of Oxidative Stress on Mitochondrial Damage and Repair in Heart Disease and Ischemic Events

The literature analysis conducted in this review discusses the latest achievements in the identification of cardiovascular damage induced by oxidative stress with secondary platelet mitochondrial dysfunction. Damage to the platelets of mitochondria as a result of their interactions with reactive oxygen species (ROS) and reactive nitrogen species (RNS) can lead to their numerous ischemic events associated with hypoxia or hyperoxia processes in the cell. Disturbances in redox reactions in the platelet mitochondrial membrane lead to the direct oxidation of cellular macromolecules, including nucleic acids (DNA base oxidation), membrane lipids (lipid peroxidation process) and cellular proteins (formation of reducing groups in repair proteins and amino acid peroxides). Oxidative changes in biomolecules inducing tissue damage leads to inflammation, initiating pathogenic processes associated with faster cell aging or their apoptosis. The consequence of damage to platelet mitochondria and their excessive activation is the induction of cardiovascular and neurodegenerative diseases (Parkinson's and Alzheimer's), as well as carbohydrate metabolism disorders (diabetes). The oxidation of mitochondrial DNA can lead to modifications in its bases, inducing the formation of exocyclic adducts of the ethano and propano type. As a consequence, it disrupts DNA repair processes and conduces to premature neoplastic transformation in critical genes such as the p53 suppressor gene, which leads to the development of various types of tumors. The topic of new innovative methods and techniques for the analysis of oxidative stress in platelet mitochondria based on methods such as a nicking assay, oxygen consumption assay, Total Thrombus formation Analysis System (T-Tas), and continuous-flow left ventricular assist devices (CF-LVADs) was also discussed. They were put together into one scientific and research platform. This will enable the facilitation of faster diagnostics and the identification of platelet mitochondrial damage by clinicians and scientists in order to implement adequate therapeutic procedures and minimize the risk of the induction of cardiovascular diseases, including ischemic events correlated with them. A quantitative analysis of the processes of thrombus formation in cardiovascular diseases will provide an opportunity to select specific anticoagulant and thrombolytic drugs under conditions of preserved hemostasis.

Heavy metals: toxicity and human health effects

Heavy metals are naturally occurring components of the Earth's crust and persistent environmental pollutants. Human exposure to heavy metals occurs via various pathways, including inhalation of air/dust particles, ingesting contaminated water or soil, or through the food chain. Their bioaccumulation may lead to diverse toxic effects affecting different body tissues and organ systems. The toxicity of heavy metals depends on the properties of the given metal, dose, route, duration of exposure (acute or chronic), and  extent of bioaccumulation. The detrimental impacts of heavy metals on human health are largely linked to their capacity to interfere with antioxidant defense mechanisms, primarily through their interaction with intracellular glutathione (GSH) or sulfhydryl groups (R-SH) of antioxidant enzymes such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR), and other enzyme systems. Although arsenic (As) is believed to bind directly to critical thiols, alternative hydrogen peroxide production processes have also been postulated. Heavy metals are known to interfere with signaling pathways and affect a variety of cellular processes, including cell growth, proliferation, survival, metabolism, and apoptosis. For example, cadmium can affect the BLC-2 family of proteins involved in mitochondrial death via the overexpression of antiapoptotic Bcl-2 and the suppression of proapoptotic (BAX, BAK) mechanisms, thus increasing the resistance of various cells to undergo malignant transformation. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important regulator of antioxidant enzymes, the level of oxidative stress, and cellular resistance to oxidants and has been shown to act as a double-edged sword in response to arsenic-induced oxidative stress. Another mechanism of significant health threats and heavy metal (e.g., Pb) toxicity involves the substitution of essential metals (e.g., calcium (Ca), copper (Cu), and iron (Fe)) with structurally similar heavy metals (e.g., cadmium (Cd) and lead (Pb)) in the metal-binding sites of proteins. Displaced essential redox metals (copper, iron, manganese) from their natural metal-binding sites can catalyze the decomposition of hydrogen peroxide via the Fenton reaction and generate damaging ROS such as hydroxyl radicals, causing damage to lipids, proteins, and DNA. Conversely, some heavy metals, such as cadmium, can suppress the synthesis of nitric oxide radical (NO·), manifested by altered vasorelaxation and, consequently, blood pressure regulation. Pb-induced oxidative stress has been shown to be indirectly responsible for the depletion of nitric oxide due to its interaction with superoxide radical (O2·-), resulting in the formation of a potent biological oxidant, peroxynitrite (ONOO-). This review comprehensively discusses the mechanisms of heavy metal toxicity and their health effects. Aluminum (Al), cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), and chromium (Cr) and their roles in the development of gastrointestinal, pulmonary, kidney, reproductive, neurodegenerative (Alzheimer's and Parkinson's diseases), cardiovascular, and cancer (e.g. renal, lung, skin, stomach) diseases are discussed. A short account is devoted to the detoxification of heavy metals by chelation via the use of ethylenediaminetetraacetic acid (EDTA), dimercaprol (BAL), 2,3-dimercaptosuccinic acid (DMSA), 2,3-dimercapto-1-propane sulfonic acid (DMPS), and penicillamine chelators.

Orthogonal Persulfide Generation through Precision Tools Provides Insights into Mitochondrial Sulfane Sulfur

The sulfane sulfur pool, comprised of persulfide (RS-SH) and polysulfide (RS-SnH) derived from hydrogen sulfide (H2S), has emerged as a major player in redox biochemistry. Mitochondria, besides energy generation, serve as significant cellular redox hubs, mediate stress response and cellular health. However, the effects of endogenous mitochondrial sulfane sulfur (MSS) remain largely uncharacterized as compared with their cytosolic counterparts, cytosolic sulfane sulfur (CSS). To investigate this, we designed a novel artificial substrate for mitochondrial 3-mercaptopyruvate sulfurtransferase (3-MST), a key enzyme involved in MSS biosynthesis. Using cells expressing a mitochondrion-localized persulfide biosensor, we demonstrate this tool's ability to selectively enhance MSS. While H2S was previously known to suppress human immunodeficiency virus (HIV-1), we found that MSS profoundly affected the HIV-1 life cycle, mediating viral reactivation from latency. Additionally, we provide evidence for the role of the host's mitochondrial redox state, membrane potential, apoptosis, and respiration rates in managing HIV-1 latency and reactivation. Together, dynamic fluctuations in the MSS pool have a significant and possibly conflicting effect on HIV-1 viral latency. The precision tools developed herein allow for orthogonal generation of persulfide within both mitochondria and the cytosol and will be useful in interrogating disease biology.

Immunohistochemical and molecular study for differential diagnosis between freshwater and saltwater drowning

The postmortem identification of drowning in the field of forensic medicine is difficult due to unspecific autopsy findings, and usually, it is a "diagnosis of exclusion". A model of drowning in salt and fresh water was established to discuss the postmortem changes after drowning and the differences between saltwater drowning (SWD) and freshwater drowning (FWD). The organs (brain and 'lung) of 30 rats were extracted at three-time points (0 h, 24 h, and 48 h) after drowning. The histopathological, immunohistochemical,l, and molecular changes in the lung and brain of rats at different time points were investigated. Results show no significant difference in pathological findings between fresh and saltwater drowning. Casp3, JNK, and ERK all showed a rise in their postmortem expression in a time-dependent way; the expression of these three genes is much greater in cases of saltwater drowning compared to cases of freshwater drowning. So, it is concluded that after 24 h and 48 h from death, potent cellular oxidative stress occurred and caused the upregulation of the studied genes.

Anethole in cancer therapy: Mechanisms, synergistic potential, and clinical challenges

Cancer remains a major global health challenge, prompting the search for effective and less toxic treatments. Anethole, a bioactive compound found in essential oils of anise and fennel, commonly used as a food preservative, has recently garnered attention for its potential anti-cancer properties. This comprehensive review aims to systematically assess the anti-cancer effects of anethole, elucidating its mechanisms of action, pharmacokinetics, bioavailability, and synergistic potential with conventional cancer therapies. A detailed literature search was conducted across databases including PubMed, Embase, Scopus, Science Direct, Web of Science, and Google Scholar. Criteria for inclusion were experimental studies in peer-reviewed journals focusing on the anti-cancer properties of anethole. Extracted data included study design, intervention specifics, measured outcomes, and mechanistic insights. Anethole demonstrates multiple anti-cancer mechanisms, such as inducing apoptosis, causing cell cycle arrest, exhibiting anti-proliferative and anti-angiogenic effects, and modulating critical signaling pathways including NF-κB, PI3K/Akt/mTOR, and caspases. It enhances the efficacy of chemotherapeutic agents like cisplatin and doxorubicin while reducing their toxicity. In vitro and in vivo studies have shown its effectiveness against various cancers, including breast, prostate, lung, and colorectal cancers. Anethole shows significant potential as an anti-cancer agent, with its multi-faceted mechanisms of action and ability to synergize with existing chemotherapy. Further clinical research is essential to fully understand its therapeutic potential and application in oncology.

Diseleno-albumin, a native bio-inspired drug free therapeutic protein induces apoptosis in lung cancer cells through mitochondrial oxidation

Macromolecular therapeutic is the emerging concept in the fields of drug delivery and drug discovery. The present study reports the design and development of a serum albumin based macromolecular chemotherapeutic by conjugating bovine serum albumin (BSA) with 3,3'-diselenodipropionic acid (DSePA), a pharmacologically active organo-diselenide (R-Se-Se-R). The reaction conditions were optimised to achieve the controlled conjugation of BSA with DSePA without causing any significant alteration in its physico-chemical properties or secondary structure and crosslinking. The chemical characterisation of the reaction product through various spectroscopic techniques viz., FT-IR, Raman, XPS, AAS and MALDI-TOF-MS, established the conjugation of about ∼5 DSePA molecules per BSA molecule. The DSePA conjugated BSA (Se-Se-BSA) showed considerable stability in aqueous and lyophilized forms. The cytotoxicity studies by involving cell lines of cancerous and non-cancerous origins indicated that Se-Se-BSA selectively inhibited the proliferation of cancerous cells. The cellular uptake studies by physically labelling Se-Se-BSA with curcumin and following its intracellular fluorescence confirmed that uptake efficiency of Se-Se-BSA was almost similar to that of native BSA. Finally, studies on the mechanism of action of Se-Se-BSA in the A549 (lung adenocarcinoma) cells revealed that it induced mitochondrial ROS generation followed by mitochondrial dysfunction, activation of caspases and apoptosis. Together, these results demonstrate a bio-inspired approach of exploring diselenide (-Se-Se-) grafted serum albumin as the potential drug free therapeutic for anticancer application.

Angelica sinensis polysaccharides mitigate cadmium-induced apoptosis in layer chicken chondrocytes by inhibiting the JNK signaling pathway

Cadmium (Cd), a toxic heavy metal pollutant, inflicts widespread damage on various organs and tissues, including cartilage, where it induces chondrocyte apoptosis. Angelica sinensis polysaccharides (ASP), a key active component of the traditional Chinese medicine Angelica sinensis, have been shown to possess anti-apoptotic effects on chondrocytes. This study investigates the in vitro effects of ASP on alleviating Cd-induced apoptosis in layer chicken chondrocytes, focusing on the mitochondrial apoptosis pathway mediated by the c-Jun N-terminal kinase (JNK) signaling pathway. Chondrocytes were isolated from layer chicken embryos and confirmed to express collagen type II alpha 1 (Col2a1). We found that Cd triggered apoptosis in the chondrocytes; however, the use of the JNK inhibitor SP 600125 mitigated mitochondrial structural damage casused by Cd, indicating the involvement of JNK signaling in this process. Furthermore, ASP effectively alleviated Cd-induced apoptosis in layer chicken chondrocytes by inhibiting JNK signaling in vitro. Our findings provide a theoretical foundation for the clinical application of ASP in preventing Cd-induced cartilage diseases in poultry.

Harnessing bacterial metabolites for enhanced cancer chemotherapy: unveiling unique therapeutic potentials

Cancer poses a serious threat to health globally, with millions diagnosed every year. According to Global Cancer Statistics 2024, about 20 million new cases were reported in 2022, and 9.7 million people worldwide died of this condition. Advanced therapies include combination of one or more treatment procedures, depending on the type, stage, and particular genetic constitution of the cancer, which may include surgery, radiotherapy, chemotherapy, immunotherapy, hormone therapy, targeted therapy, and stem cell transplant. Also, awareness about lifestyle changes, preventive measures and screening at early stages has reduced the incidence of the disease; still, there is a major failure in controlling the incidence of cancer because of its complex and multifaceted nature. With increasing interest in bacterial metabolites as possible novel and effective treatment options in cancer therapy, their main benefits include not only direct anticancer effects but also the modulation of the immune system and potential for targeted and combination therapies. They can therefore be used in combination with chemotherapy, radiotherapy, or immunotherapy to improve outcomes or reduce side effects. Furthermore, nanoparticle-based delivery systems have the potential to enhance the potency and safety of anticancer drugs by providing improved stability, targeted release, and controlled delivery.

Pharmacological Preconditioning with Fenofibrate in Cardiomyocyte Cultures of Neonatal Rats Subjected to Hypoxia/Reoxygenation, High Glucose, and Their Combination

Pharmacological preconditioning is an alternative to protect the heart against the consequences of damage from ischemia/reperfusion (I/R). It is based on the administration of specific drugs that imitate the effect of ischemic preconditioning (IPC). Peroxisomal proliferator-activated receptors (PPARs) can prevent apoptosis in pathologies such as I/R and heart failure. Therefore, our objective was to determine if the stimulation of PPARα with fenofibrate (feno) decreases the apoptotic process induced by hypoxia/reoxygenation (HR), high glucose (HG), and HR/HG. For that purpose, cardiomyocyte cultures were divided into the following groups: Group 1-control (Ctrl); Group 2-HR; Group 3-HR + 10 μM feno; Group 4-HG, (25 mM glucose); Group 5-HG + feno; Group 6-HR/HG, and Group 7-HR/HG + feno. Our results indicate that cell viability decreases in neonatal cardiomyocytes undergoing HR, HG, and their combination, while feno improved cell viability. Feno treatment decreased apoptosis compared with HG-, HR-, or HG/HR-vehicle-treated. Nuclear- and mitochondrial-apoptosis markers increased in neonatal cardiomyocytes from HR, HG, and HR/HG; while the cytotoxicity decreased in cells treated with feno. In addition, the expression of Bax, Bad, and caspase 9 decreased due to feno, while 14-3-3ɛ and Bcl2 were increased. Inner mitochondrial cytochrome C increased with feno in every condition, as well as mitochondrial activity. Feno treatment prevented injury in the ultrastructure and in the mitochondrial membranes. Thus, our results suggest that feno decreases apoptosis in neonatal cardiomyocytes, improving the ultrastructure of mitochondria in the pathological conditions studied.

A Selective Melatonin 2 Receptor Agonist, IIK7, Relieves Blue Light-Induced Corneal Damage by Modulating the Process of Autophagy and Apoptosis

This study aims to investigate the effect of the selective MT2 receptor agonist, IIK7, on corneal autophagy and apoptosis, aiming to reduce corneal epithelial damage and inflammation from blue light exposure in mice. Eight-week-old C57BL/6 mice were divided into BL-exposed (BL) and BL-exposed with IIK7 treatment (BL + IIK7 group). Mice underwent blue light exposure (410 nm, 100 J) twice daily with assessments at baseline and on days 3, 7, and 14. Corneal samples were analyzed for MT2 receptor expression, autophagy markers (LC3-II and p62), and apoptosis indicators (BAX expression and TUNEL assay). Then, mice were assigned to normal control, BL, and BL + IIK7. Ocular surface parameters, including corneal fluorescein staining scores, tear volume, and tear film break-up time, were evaluated on days 7 and 14. On day 14, reactive oxygen species (ROS) levels and CD4+ IFN-γ+ T cells percentages were measured. The BL group exhibited higher LC3-II and p62 expression, while the BL + IIK7 group showed reduced expression (p < 0.05). The TUNEL assay showed reduced apoptosis in the BL + IIK7 group compared to the BL group. ROS levels were lower in the BL + IIK7 group. The BL + IIK7 group showed improved ocular surface parameters, including decreased corneal fluorescein staining and increased tear volume. The percentages of CD4+ IFN-γ+ T cells indicated reduced inflammatory responses in the BL + IIK7 group. The MT2 receptor agonist IIK7 regulates corneal autophagy and apoptosis, reducing corneal epithelial damage and inflammation from blue light exposure.

Regulation of the NLRP3 inflammasome by autophagy and mitophagy

The NLRP3 inflammasome is a multiprotein complex that upon activation by the innate immune system drives a broad inflammatory response. The primary initial mediators of this response are pro-IL-1β and pro-IL-18, both of which are in an inactive form. Formation and activation of the NLRP3 inflammasome activates caspase-1, which cleaves pro-IL-1β and pro-IL-18 and triggers the formation of gasdermin D pores. Gasdermin D pores allow for the secretion of active IL-1β and IL-18 initiating the organism-wide inflammatory response. The NLRP3 inflammasome response can be beneficial to the host; however, if the NLRP3 inflammasome is inappropriately activated it can lead to significant pathology. While the primary components of the NLRP3 inflammasome are known, the precise details of assembly and activation are less well defined and conflicting. Here, we discuss several of the proposed pathways of activation of the NLRP3 inflammasome. We examine the role of subcellular localization and the reciprocal regulation of the NLRP3 inflammasome by autophagy. We focus on the roles of mitochondria and mitophagy in activating and regulating the NLRP3 inflammasome. Finally, we detail the impact of pathologic NLRP3 responses in the development and manifestations of pulmonary disease.

Difenoconazole Induced Damage of Bovine Mammary Epithelial Cells via ER Stress and Inflammatory Response

Difenoconazole (DIF) is a fungicide used to control various fungi. It is absorbed on the surface of different plants and contributes significantly to increased crop production. However, DIF is reported to exhibit toxicity to fungi and to aquatic plants, fish, and mammals, including humans, causing adverse effects. However, research on the impact of DIF on the mammary epithelial cells of herbivorous bovines is limited. DIF-induced damage and accumulation in the mammary glands can have direct and indirect effects on humans. Therefore, we investigated the effects and mechanisms of DIF toxicity in MAC-T cells. The current study revealed that DIF reduces cell viability and proliferation while triggering apoptotic cell death through the upregulation of pro-apoptotic proteins, including cleaved caspase 3 and Bcl-2-associated X protein (BAX), and the downregulation of leukemia type 2 (BCL-2). DIF also induced endoplasmic reticulum (ER) stress by increasing the expression of genes or proteins of Bip/GRP78, protein disulfide isomerase (PDI), activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), and endoplasmic reticulum oxidoreductase 1 Alpha (ERO1-Lα). We demonstrated that DIF induces mitochondria-mediated apoptosis in MAC-T cells by activating ER stress pathways. This cellular damage resulted in a significant increase in the expression of inflammatory response genes and proteins, including cyclooxygenase 2 (COX2), transforming growth factor beta 3 (TGFB3), CCAAT enhancer binding protein delta (CEBPD), and iNOS, in DIF-treated groups. In addition, spheroid formation by MAC-T cells was suppressed by DIF treatment. Our findings suggest that DIF exposure in dairy cows may harm mammary gland function and health and may indirectly affect human consumption of milk.

Carbon Chain Length in a Novel Anticancer Aryl-Urea Fatty Acid Modulates Mitochondrial Targeting, Reactive Oxygen Species Production and Cell Killing

The cancer cell mitochondrion could be a promising target for the development of new anticancer agents. 16-([3-chloro-5-(trifluoromethyl)-phenyl]carbamoylamino)hexadecanoic acid (2) is a novel aryl-urea fatty acid that targets the mitochondrion in MDA-MB-231 breast cancer cells and activates cell death. In the present study, the relationships between alkyl chain length in 2 analogues, mitochondrial disruption and cell killing were evaluated. The chain-contracted C13-analogue 7 c optimally disrupted the mitochondrial membrane potential (IC50 4.8±0.8 μM). In addition, annexin V-FITC/7-AAD assays demonstrated that 7 c was the most effective cell killing analogue and C11 BODIPY (581/591) assays demonstrated that 7 c was also most effective in generating reactive oxygen species in MDA-MB-231 cells. Together, carbon chain length is a key factor that determines the capacity of 2 analogues to disrupt the mitochondrial membrane, induce the production of reactive oxygen species and kill breast cancer cells. As an aryl-urea with enhanced activity and improved drug-like properties, 7 c may be a suitable lead molecule for entry into a program of development of these molecules as anticancer agents.

Immunomodulatory Functions of TNF-Related Apoptosis-Inducing Ligand in Type 1 Diabetes

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF protein superfamily and was initially identified as a protein capable of inducing apoptosis in cancer cells. In addition, TRAIL can promote pro-survival and proliferation signaling in various cell types. Subsequent studies have demonstrated that TRAIL plays several important roles in immunoregulation, immunosuppression, and immune effector functions. Type 1 diabetes (T1D) is an autoimmune disease characterized by hyperglycemia due to the loss of insulin-producing β-cells, primarily driven by T-cell-mediated pancreatic islet inflammation. Various genetic, epigenetic, and environmental factors, in conjunction with the immune system, contribute to the initiation, development, and progression of T1D. Recent reports have highlighted TRAIL as an important immunomodulatory molecule with protective effects on pancreatic islets. Experimental data suggest that TRAIL protects against T1D by reducing the proliferation of diabetogenic T cells and pancreatic islet inflammation and restoring normoglycemia in animal models. In this review, we aimed to summarize the consequences of TRAIL action in T1D, focusing on and discussing its signaling mechanisms, role in the immune system, and protective effects in T1D.

Siah3 acts as a physiological mitophagy suppressor that facilitates axonal degeneration

Mitophagy eliminates dysfunctional mitochondria, and defects in this cellular housekeeping mechanism are implicated in various age-related diseases. Here, we found that mitophagy suppression by the protein Siah3 promoted developmental axonal remodeling in mice. Siah3-deficient mice displayed increased peripheral sensory innervation. Cultured Siah3-deficient sensory neurons exhibited delays in both axonal degeneration and caspase-3 activation in response to withdrawal of nerve growth factor. Mechanistically, Siah3 was transcriptionally induced by the loss of trophic support and formed a complex with the cytosolic E3 ubiquitin ligase parkin, a core component of mitophagy, in transfected cells. Axons of Siah3-deficient neurons mounted profound mitophagy upon initiation of degeneration but not under basal conditions. Neurons lacking both Siah3 and parkin did not exhibit the delay in trophic deprivation-induced axonal degeneration or the induction of axonal mitophagy that was seen in Siah3-deficient neurons. Our findings reveal that mitophagy regulation acts as a gatekeeper of a physiological axon elimination program.

Targeting Mitochondrial Guanine Quadruplexes for Photoactivatable Chemotherapy in Hypoxic Environments

A first example of a mitochondrial G-quadruplex (mitoG4s) targeted Ru(II) photooxidant complex is reported. The complex, Ru-TAP-PDC3 induces photodamage toward guanine quadruplexes (G4s) located in the mitochondrial genome under hypoxic and normoxic conditions. Ru-TAP-PDC3 shows high affinity for mitoG4s and localises within mitochondria of live HeLa cells. Immunolabelling with anti-G4 antibody, BG4, confirms Ru-TAP-PDC3 associates with G4s within the mitochondria of fixed cells. The complex induces depletion of mtDNA in live cells under irradiation at 405 nm, confirmed by loss of PicoGreen signal from mitochondria. Biochemical studies confirm this process induces apoptosis. The complex shows low dark toxicity and an impressive phototoxicity index (PI) of >89 was determined in Hela under very low intensity irradiation, 5 J/cm2. The phototoxicity is thought to operate through both Type II singlet oxygen and Type III pathways depending on normoxic or hypoxic conditions, from live cell assays and plasmid DNA cleavage. Overall, we demonstrate targeting mitoG4s and mtDNA with a photooxidant is a potent route to achieving apoptosis under hypoxic conditions that can be extended to phototherapy.

Crude extract of Ruellia tuberosa L. flower induces intracellular ROS, promotes DNA damage and apoptosis in triple negative breast cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Ruellia tuberosa L. (Acanthaceae) is a weed plant traditionally used in folklore medicine as a diuretic, anti-hypertensive, anti-pyretic, anti-cancerous, anti-diabetic, analgesic, and gastroprotective agent. It has been previously reported that R. tuberosa L. is enriched with various flavonoids, exhibiting significant cytotoxic potential in various cancer models but a detailed study concerning its molecular mechanism is yet to be explored.

AIM OF THE STUDY

Exploring and validating R. tuberosa L. flower methanolic extract (RTME) as an anti-cancerous agent as per traditional usage with special emphasis on multi-drug resistant human triple-negative breast cancer (TNBC) and investigating the possible signaling networks and regulatory pathways involved in it.

MATERIALS AND METHODS

In this study, RTME was prepared using methanol, and phytochemical analysis was performed through GC-MS. Then, the extract was tested for its anti-cancer potential through in-vitro cytotoxicity assay, clonogenic assay, wound healing assay, ROS generation assay, cell cycle arrest, apoptotic nuclear morphology study, cellular apoptosis study, mitochondrial membrane potential (MMP) alteration study, protein, and gene expressions alteration study. In addition, toxicological status was evaluated in female Balb/C mice, and to check the receptor-ligand interactions, in-silico molecular docking was also conducted.

RESULTS

Several phytochemicals were found within RTME through GC-MS, which have been already reported to act as ROS inductive, DNA damaging, cell cycle arresting, and apoptotic agents against cancer cells. Moreover, RTME was found to exhibit significant in-vitro cytotoxicity along with a reduction in colony formation, and inhibition of cell migratory potential. It also induced intracellular ROS, promoted G0/G1 cell cycle arrest, caused mitochondrial membrane potential (MMP) alteration, and promoted cell death. The Western blot and qRT-PCR data revealed that RTME promoted the intrinsic pathway of apoptosis. Furthermore, blood parameters and organ histology on female Balb/C mice disclosed the non-toxic nature of RTME. Finally, an in-silico molecular docking study displayed that the three identified lead phytochemicals in RTME show strong receptor-ligand interactions with the anti-apoptotic Bcl-2 and give a clue to the possible molecular mechanism of the RTME extract.

CONCLUSIONS

RTME is a potential source of several phytochemicals that have promising therapeutic potential against TNBC cells, and thus could further be utilized for anti-cancer drug development.

Context-dependent roles of mitochondrial LONP1 in orchestrating the balance between airway progenitor versus progeny cells

While all eukaryotic cells are dependent on mitochondria for function, in a complex tissue, which cell type and which cell behavior are more sensitive to mitochondrial deficiency remain unpredictable. Here, we show that in the mouse airway, compromising mitochondrial function by inactivating mitochondrial protease gene Lonp1 led to reduced progenitor proliferation and differentiation during development, apoptosis of terminally differentiated ciliated cells and their replacement by basal progenitors and goblet cells during homeostasis, and failed airway progenitor migration into damaged alveoli following influenza infection. ATF4 and the integrated stress response (ISR) pathway are elevated and responsible for the airway phenotypes. Such context-dependent sensitivities are predicted by the selective expression of Bok, which is required for ISR activation. Reduced LONP1 expression is found in chronic obstructive pulmonary disease (COPD) airways with squamous metaplasia. These findings illustrate a cellular energy landscape whereby compromised mitochondrial function could favor the emergence of pathological cell types.

Mitochondrial signaling pathways and their role in cancer drug resistance

Mitochondria, traditionally known as cellular powerhouses, now emerge as critical signaling centers influencing cancer progression and drug resistance. The review highlights the role that apoptotic signaling, DNA mutations, mitochondrial dynamics and metabolism play in the development of resistance mechanisms and the advancement of cancer. Targeted approaches are discussed, with an emphasis on managing mitophagy, fusion, and fission of the mitochondria to make resistant cancer cells more susceptible to traditional treatments. Additionally, metabolic reprogramming can be used to effectively target metabolic enzymes such GLUT1, HKII, PDK, and PKM2 in order to avoid resistance mechanisms. Although there are potential possibilities for therapy, the complex structure of mitochondria and their subtle role in tumor development hamper clinical translation. Novel targeted medicines are put forth, providing fresh insights on combating drug resistance in cancer. The study also emphasizes the significance of glutamine metabolism, mitochondrial respiratory complexes, and apoptotic pathways as potential targets to improve treatment effectiveness against drug-resistant cancers. Combining complementary and nanoparticle-based techniques to target mitochondria has demonstrated encouraging results in the treatment of cancer, opening doors to reduce resistance and enable individualized treatment plans catered to the unique characteristics of each patient. Suggesting innovative approaches such as drug repositioning and mitochondrial drug delivery to enhance the efficacy of mitochondria-targeting therapies, presenting a pathway for advancements in cancer treatment. This thorough investigation is a major step forward in the treatment of cancer and has the potential to influence clinical practice and enhance patient outcomes.

Potential Role of Dipeptidyl Peptidase-4 in Regulating Mitochondria and Oxidative Stress in Cardiomyocytes

Oxidative stress causes mitochondrial damage and bioenergetic dysfunction and inhibits adenosine triphosphate production, contributing to the pathogenesis of cardiac diseases. Dipeptidyl peptidase 4 (DPP4) is primarily a membrane-bound extracellular peptidase that cleaves Xaa-Pro or Xaa-Ala dipeptides from the N terminus of polypeptides. DPP4 inhibitors have been used in patients with diabetes and heart failure; however, they have led to inconsistent results. Although the enzymatic properties of DPP4 have been well studied, the substrate-independent functions of DPP4 have not. In the present study, we knocked down DPP4 in cultured cardiomyocytes to exclude the effects of differential alteration in the substrates and metabolites of DPP4 then compared the response between the knocked-down and wild-type cardiomyocytes during exposure to oxidative stress. H2O2 exposure induced DPP4 expression in both types of cardiomyocytes. However, knocking down DPP4 substantially reduced the loss of cell viability by preserving mitochondrial bioenergy, reducing intracellular reactive oxygen species production, and reducing apoptosis-associated protein expression. These findings demonstrate that inhibiting DPP4 improves the body's defense against oxidative stress by enhancing Nrf2 and PGC-1α signaling and increasing superoxide dismutase and catalase activity. Our results indicate that DPP4 mediates the body's response to oxidative stress in individuals with heart disease.

C-terminal region of Rv1039c (PPE15) protein of Mycobacterium tuberculosis targets host mitochondria to induce macrophage apoptosis

Mycobacterium tuberculosis (Mtb) genome possesses a unique family called Proline-Glutamate/Proline-Proline-Glutamate (PE/PPE) gene family, exclusive to pathogenic mycobacterium. Some of these proteins are known to play role in virulence and immune response modulation, but many are still uncharacterized. This study investigated the role of C-terminal region of Rv1039c (PPE15) in inducing mitochondrial perturbations and macrophage apoptosis. Our in-silico studies revealed the disordered, coiled, and hydrophobic C-terminal region in Rv1039c has similarity with C-terminal of mitochondria-targeting pro-apoptotic host proteins. Wild type Rv1039c and C-terminal deleted Rv1039c (Rv1039c-/-Cterm) recombinant proteins were purified and their M. smegmatis knock-in strains were constructed which were used for in-vitro experiments. Confocal microscopy showed localization of Rv1039c to mitochondria of PMA-differentiated THP1 macrophages; and reduced mitochondrial membrane depolarization and production of mitochondrial superoxides were observed in response to Rv1039c-/-Cterm in comparison to full-length Rv1039c. The C-terminal region of Rv1039c was found to activate caspases 3, 7 and 9 along with upregulated expression of pro-apoptotic genes like Bax and Bim. Rv1039c-/-Cterm also reduced the Cytochrome-C release from the mitochondria and the expression of AnnexinV/PI positive and TUNEL positive cells as compared to Rv1039c. Additionally, Rv1039c was observed to upregulate the TLR4-NF-κB-TNF-α signalling whereas the same was downregulated in response to Rv1039c-/-Cterm. These findings suggested that the C-terminal region of Rv1039c is a molecular mimic of pro-apoptotic host proteins which induce mitochondria-dependent macrophage apoptosis and evoke host immune response. These observations enhance our understanding about the role of PE/PPE proteins at host-pathogen interface.

CARM1 phosphorylation at S595 by p38γ MAPK drives ROS-mediated cellular senescence

CARM1 is predominantly localized in the nucleus and plays a pivotal role in maintaining mitochondrial homeostasis by regulating gene expression. It suppresses mitochondrial biogenesis by downregulating PGC-1α and TFAM expression, while promoting mitochondrial fission through increased DNM1L expression. Under oxidative stress, CARM1 translocates to the cytoplasm, where it directly methylates DRP1 and accelerates mitochondrial fission, enhancing reactive oxygen species (ROS) production. Cytoplasmic localization of CARM1 is facilitated by its phosphorylation at S595 by ROS-activated p38γ MAPK, creating a positive feedback loop. Consequently, cytoplasmic CARM1 contributes to cellular senescence by altering mitochondrial dynamics and increasing ROS levels. This observation was supported by the increased cytoplasmic CARM1 levels and disrupted mitochondrial dynamics in the transformed 10T1/2 cells. Moreover, CARM1 inhibitors not only inhibit the proliferation of cancer cells but also induce apoptotic death in senescent cells. These findings highlight the potential of CARM1 inhibitors, particularly those targeting cytoplasmic functions, as novel strategies for eliminating cancer and senescent cells.

Update on Biomarkers of Chronic Inflammatory Processes Underlying Diabetic Neuropathy

There is an increasing prevalence of diabetes mellitus (DM), particularly type 2 DM (T2DM), and its associated complications. T2DM is linked to insulin resistance, chronic inflammation, and oxidative stress, which can lead to both macrovascular and microvascular complications, including peripheral diabetic neuropathy (PDN). Inflammatory processes play a key role in the development and progression of T2DM and its complications, with specific markers like C-reactive protein (CRP), interleukins (ILs), and tumor necrosis factor (TNF)-α being associated with increased risk. Other key inflammatory markers such as nuclear factor kappa B (NF-κB) are activated under hyperglycemic and oxidative stress conditions and contribute to the aggravation of PDN by regulating inflammatory gene expression and enhancing endothelial dysfunction. Other important roles in the inflammatory processes are played by Toll-like receptors (TLRs), caveolin 1 (CAV1), and monocyte chemoattractant protein 1 (MCP1). There is a relationship between vitamin D deficiency and PDN, highlighting the critical role of vitamin D in regulating inflammation and immune responses. The involvement of macrophages in PDN is also suspected, emphasizing their role in chronic inflammation and nerve damage in diabetic patients. Vitamin D supplementation has been found to reduce neuropathy severity, decrease inflammatory markers, and improve glycemic control. These findings suggest that addressing vitamin D deficiency could offer therapeutic benefits for PDN. These molecular pathways are critical in understanding the pathogenesis of DM complications and may offer potential biomarkers or therapeutic targets including anti-inflammatory treatments, vitamin D supplementation, macrophage phenotype modulation, and lifestyle modifications, aimed at reducing inflammation and preventing PDN. Ongoing and more extensive clinical trials with the aim of investigating anti-inflammatory agents, TNF-α inhibitors, and antioxidants are needed to advance deeper into the understanding and treatment of painful diabetic neuropathy.

Visualizing Mitochondrial Membrane Potential with FRET Probes: Integrating Fluorescence Intensity Ratio and Lifetime Imaging

Mitochondrial membrane potential (MMP) is crucial for mitochondrial function and serves as a key indicator of cellular health and metabolic activity. Traditional lipophilic cationic fluorescence intensity probes are unavoidably influenced by probe concentration, laser intensity, and photobleaching, limiting their accuracy. To address these issues, we designed and synthesized a pair of fluorescence molecules, OR-C8 and SiR-BA, based on the Förster Resonance Energy Transfer (FRET) mechanism, for dual-modality visualization of MMP. OR-C8 anchors to the inner mitochondrial membrane through strong hydrophobic interactions, while SiR-BA is expelled from mitochondria when MMP decreases, thereby regulating the FRET process. During MMP reduction, the fluorescence intensity and lifetime of OR-C8 increase, while the fluorescence intensity of SiR-BA decreases. By combining changes in fluorescence intensity ratio and fluorescence lifetime, dual-modality visualization of MMP was achieved. This method not only accurately reflects MMP changes but also provides a novel tool for in-depth studies of mitochondrial function and related disease mechanisms, offering significant potential for advancing mitochondrial research and therapeutic development.

Effect of Methyl Glycoside on Apoptosis and Oxidative Stress in Hypoxia Induced-Reoxygenated H9C2 Cell Lines

This study focuses on key genes (Caspase-3, JAK2, BCL2L1 and MAPK8) and their modulation in response to hypoxia-induced stress using Methyl Glycoside (MG), a small molecule spectroscopically screened from Aganosma dichotoma. Hypoxia/reoxygenation (H/R) induced H9C2 cells, pre- treated with MG, were subjected to cell viability assay, free radical scavenging activities (catalase, GST, GSH-Px, SOD), caspase activity, mitochondrial membrane potential, and gene expression profiling through standard assays and molecular techniques. Results indicated that MG treatment, has potential protective effects against H/R induced stress in H9C2 cell lines. Cell viability assays showed that MG maintained cellular viability with significant protection (P < 0.05) observed from 10 µM. Free radical scavenging assays revealed that MG, enhanced detoxification mechanisms and exhibited potential antioxidant effect in a significantly (P < 0.05) in a dose dependant manner. MG pre-treatment in H9C2 cells protected cellular damage from caspase activity, cells exhibited high mitochondrial membrane potential, and gene expression profiles, including upregulation of anti-apoptotic BCL2L1 and modulation of stress-responsive genes like CASP3, JAK2 and MAPK8. Hence, MG exhibited concentration-dependent protective effects on viability, oxidative stress, and apoptosis-related pathways, laying the foundation for further exploration and translational applications in cardiovascular interventions.

The role of cilia in the development, survival, and regeneration of hair cells

Mutations impacting cilia genes lead to a class of human diseases known as ciliopathies. This is due to the role of cilia in the development, survival, and regeneration of many cell types. We investigated the extent to which disrupting cilia impacted these processes in lateral line hair cells of zebrafish. We found that mutations in two intraflagellar transport (IFT) genes, ift88 and dync2h1, which lead to the loss of kinocilia, caused increased hair cell apoptosis. IFT gene mutants also have a decreased mitochondrial membrane potential, and blocking the mitochondrial uniporter causes a loss of hair cells in wild-type zebrafish but not mutants, suggesting mitochondria dysfunction may contribute to the apoptosis seen in these mutants. These mutants also showed decreased proliferation during hair cell regeneration but did not show consistent changes in support cell number or proliferation during hair cell development. These results show that the loss of hair cells seen following disruption of cilia through either mutations in anterograde or retrograde IFT genes appears to be due to impacts on hair cell survival but not necessarily development in the zebrafish lateral line.

Dual-Modality Imaging with a Zwitterionic Fluorescent Probe for Reversible Monitoring of Mitochondrial Membrane Potential Dynamics

Traditional fluorescence intensity-based probes face challenges in accurately measuring mitochondrial membrane potential (MMP) due to intramolecular fluorescence quenching. In this work, we introduce a novel approach by incorporating quenching moieties within the zwitterionic probe to eliminate self-quenching interference, thus, enabling real-time and precise visualization of reversible MMP changes. We synthesized a zwitterionic fluorescent probe consisting of silicon-rhodamine (SiR) that was hydroxyl-substituted on the bay position of perylene diimides (PDIs) connected via a polyethylene glycol (PEG) linker. The lipophilic cationic SiR facilitates the entry of the PDI into the mitochondria, where the alkaline pH environment (pH = 8.0) ionizes the hydroxyl to a negatively charged species, affecting the quenching efficiency of SiR depending on the distance between the PDI and SiR moieties regulated by the MMP. The rigid aromatic ring of the PDI and strong hydrophobic interactions with the lipid bilayer, along with the inhibitory effect of the negatively charged hydroxyl on internalization, ensure the retention of PDI within the mitochondria. As the MMP decreases, SiR shifts outward, reducing quenching by phenolic anions and restoring fluorescence. Conversely, as the MMP increases, SiR moves inward, intensifying quenching by phenolic ions and reducing fluorescence, enabling reversible visualization monitoring of the MMP. This strategy overcomes the limitations of traditional intensity-based probes, providing a new avenue for reversible monitoring of the MMP.

The multifaceted role of mitochondria in autism spectrum disorder

Normal brain functioning relies on high aerobic energy production provided by mitochondria. Failure to supply a sufficient amount of energy, seen in different brain disorders, including autism spectrum disorder (ASD), may have a significant negative impact on brain development and support of different brain functions. Mitochondrial dysfunction, manifested in the abnormal activities of the electron transport chain and impaired energy metabolism, greatly contributes to ASD. The aberrant functioning of this organelle is of such high importance that ASD has been proposed as a mitochondrial disease. It should be noted that aerobic energy production is not the only function of the mitochondria. In particular, these organelles are involved in the regulation of Ca2+ homeostasis, different mechanisms of programmed cell death, autophagy, and reactive oxygen and nitrogen species (ROS and RNS) production. Several syndromes originated from mitochondria-related mutations display ASD phenotype. Abnormalities in Ca2+ handling and ATP production in the brain mitochondria affect synaptic transmission, plasticity, and synaptic development, contributing to ASD. ROS and Ca2+ regulate the activity of the mitochondrial permeability transition pore (mPTP). The prolonged opening of this pore affects the redox state of the mitochondria, impairs oxidative phosphorylation, and activates apoptosis, ultimately leading to cell death. A dysregulation between the enhanced mitochondria-related processes of apoptosis and the inhibited autophagy leads to the accumulation of toxic products in the brains of individuals with ASD. Although many mitochondria-related mechanisms still have to be investigated, and whether they are the cause or consequence of this disorder is still unknown, the accumulating data show that the breakdown of any of the mitochondrial functions may contribute to abnormal brain development leading to ASD. In this review, we discuss the multifaceted role of mitochondria in ASD from the various aspects of neuroscience.

Carbon nanotubes conjugated with cisplatin activate different apoptosis signaling pathways in 2D and 3D-spheroid triple-negative breast cancer cell cultures: a comparative study

The type of experimental model for the in vitro testing of drug formulations efficiency represents an important tool in cancer biology, with great attention being granted to three-dimensional (3D) cultures as these offer a closer approximation of the clinical sensitivity of drugs. In this study, the effects induced by carboxyl-functionalized single-walled carbon nanotubes complexed with cisplatin (SWCNT-COOH-CDDP) and free components (SWCNT-COOH and CDDP) were compared between conventional 2D- and 3D-spheroid cultures of human breast cancer cells. The 2D and 3D breast cancer cultures were exposed to various doses of SWCNT-COOH (0.25-2 μg/mL), CDDP (0.158-1.26 μg/mL) and the same doses of SWNCT-COOH-CDDP complex for 24 and 48 h. The anti-tumor activity, including modulation of cell viability, oxidative stress, proliferation, apoptosis, and invasion potential, was explored by spectrophotometric and fluorometric methods, immunoblotting, optical and fluorescence microscopy. The SWCNT-COOH-CDDP complex proved to have high anti-cancer efficiency on 2D and 3D cultures by inhibiting cell proliferation and activating cell death. A dose of 0.632 μg/mL complex triggered different pathways of apoptosis in 2D and 3D cultures, by intrinsic, extrinsic, and reticulum endoplasmic pathways. Overall, the 2D cultures showed higher susceptibility to the action of complex compared to 3D cultures and SWCNT-COOH-CDDP proved enhanced anti-tumoral activity compared to free CDDP.

Domperidone, a Dopamine Receptor D2 Antagonist, Induces Apoptosis by Inhibiting the ERK/STAT3-Mediated Pathway in Human Colon Cancer HCT116 Cells

Colorectal cancer (CRC) continues to demonstrate high incidence and mortality rates, emphasizing that implementing strategic measures for prevention and treatment is crucial. Recently, the dopamine receptor D2 (DRD2), a G protein-coupled receptor, has been reported to play multiple roles in growth of tumor cells. This study investigated the anticancer potential of domperidone, a dopamine receptor D2 antagonist, in HCT116 human CRC cells. Domperidone demonstrated concentration- and time-dependent reductions in cell viability, thereby inducing apoptosis. The molecular mechanism revealed that domperidone modulated the mitochondrial pathway, decreasing mitochondrial Bcl-2 levels, elevating cytosolic cytochrome C expression, and triggering caspase- 3, -7, and -9 cleavage. Domperidone decreased in formation of β-arrestin2/MEK complex, which contributing to inhibition of ERK activation. Additionally, treatment with domperidone diminished JAK2 and STAT3 activation. Treatment of U0126, the MEK inhibitor, resulted in reduced phosphorylation of MEK, ERK, and STAT3 without alteration of JAK2 activation, indicating that domperidone targeted both MEK-ERK-STAT3 and JAK2-STAT3 signaling pathways, respectively. Immunoblot analysis revealed that domperidone also downregulated DRD2 expression. Domperidone-induced reactive oxygen species (ROS) generation and N-acetylcysteine treatment mitigated ROS levels and restored cell viability. An in vivo xenograft study verified the significant antitumor effects of domperidone. These results emphasize the multifaceted anticancer effects of domperidone, highlighting its potential as a promising therapeutic agent for human CRC.

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

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

Role of Nitric Oxide, TNF-α and Caspase-3 in Lead Acetate-Exposed Rats Pretreated with Aqueous Rosmarinus officinalis Leaf Extract

Lead (Pb) toxicity is a worldwide significant public health challenge causing several neurological disorders. Reports indicate that plants rich in antioxidants, such as Rosmarinus officinalis (RO), can counteract Pb accumulation and its toxicity in the brain. Due to a dearth of literature evidence demonstrating the protective activity of RO against Pb toxicity, this study investigated such activity in Wistar rats. Thirty-six Wistar rats were allocated into six groups (n=6), namely I (control), II (lead acetate [Pb]; 100 mg/kg b.w.), III (100 mg/kg of RO and 100 mg/kg of Pb), IV (200 mg/kg of RO and 100 mg/kg of Pb), V (100 mg/kg b.w. of RO) and VI (200 mg/kg b.w. of RO). After 28 days, neurobehavioural, antioxidant, lipid peroxidation, apoptotic and inflammatory activities as well as the histology of the cerebellum were evaluated. Body weight, locomotion and exploration as well as antioxidant enzymes were significantly (p < 0.05) decreased in Pb-exposed rats when compared to control. Conversely, lipid peroxidation, nitric oxide, tumour necrosis factor-alpha and caspase-3 activities were significantly (p < 0.05) upregulated in the Pb-exposed rats when compared to control. These parameters were, however, significantly (p<0.05) attenuated in the RO-pretreated rats when compared to Pb-exposed rats. Cerebellar histology of the Pb-exposed rats showed severe degeneration of the Purkinje cells whereas the RO-pretreated rats showed better cerebellar architecture. These findings demonstrate that the neuroprotective activity of RO is facilitated via its effective antioxidant, anti-inflammatory and anti-apoptotic effects.

Investigating the Anticancer Potential of Biochanin A in KB Oral Cancer Cells Through the NFκB Pathway

Squamous cell carcinoma (SCC) is a malignancy primarily affecting squamous cells. Its development is linked to multiple risk factors, such as alcohol and tobacco consumption, human papillomavirus (HPV) infection, and Epstein-Barr Virus (EBV) infection. Biochanin A (BCA), a phytoestrogen extracted from red clover, has been extensively researched for its therapeutic properties. It spans antioxidant activity, anti-inflammatory effects, neuroprotection, cardioprotection, and anticancer potential in different bodily systems. However, its impact on oral cancer remains unexplored. Therefore, this investigation aims to assess the potential anticancer effects of BCA, specifically on KB oral cancer cells. This study utilized KB cells to evaluate the impact of BCA on various cellular parameters, including cell viability, apoptosis, intracellular ROS production, mitochondrial membrane potential, and cell migration. BCA treatment induced several notable effects on KB cells, including reduced cell viability, altered morphology suggestive of apoptosis, heightened oxidative stress, and alterations in mitochondrial membrane potential. Moreover, BCA treatment demonstrated an inhibitory effect on cell migration. The study further investigated the impact of BCA on antioxidant enzyme activities and lipid peroxidation, revealing decreased antioxidant enzyme activities and increased lipid peroxidation across different BCA concentrations (IC50 and IC90). Immunocytochemistry and qRT-PCR analyses unveiled that BCA treatment at varying doses (IC50 and IC90) downregulated the expression of nuclear factor-κB (NF-κB) subunits p50 and p65, pivotal players in cancer progression. In summary, this study sheds light on the promising potential of BCA as an anticancer therapeutic agent for treating oral cancer. Its demonstrated ability to induce apoptosis, perturb cellular functions, and modulate gene expression within cancer cells underscores its significance. Nonetheless, further research, particularly following animal studies, is imperative to comprehensively grasp the breadth of BCA's effects and its viability for clinical applications.

Post-Acute Sequelae and Mitochondrial Aberration in SARS-CoV-2 Infection

This review investigates links between post-acute sequelae of SARS-CoV-2 infection (PASC), post-infection viral persistence, mitochondrial involvement and aberrant innate immune response and cellular metabolism during SARS-CoV-2 infection. Advancement of proteomic and metabolomic studies now allows deeper investigation of alterations to cellular metabolism, autophagic processes and mitochondrial dysfunction caused by SARS-CoV-2 infection, while computational biology and machine learning have advanced methodologies of predicting virus-host gene and protein interactions. Particular focus is given to the interaction between viral genes and proteins with mitochondrial function and that of the innate immune system. Finally, the authors hypothesise that viral persistence may be a function of mitochondrial involvement in the sequestration of viral genetic material. While further work is necessary to understand the mechanisms definitively, a number of studies now point to the resolution of questions regarding the pathogenesis of PASC.

Synergistic Treatment of Breast Cancer by Combining the Antimicrobial Peptide Piscidin with a Modified Glycolipid

Piscidin 3 (P3), a peptide produced by fish, and a hexyl ester-modified sophorolipid (SL-HE), have individually shown promise as antimicrobial and anticancer drugs. A recent report by our team revealed that combining P3 with SL-HE in a 1:8 molar ratio resulted in an 8-fold enhancement in peptide activity, while SL-HE improved by 25-fold its antimicrobial activity against the Gram-positive microorganism Bacillus cereus. Extending these findings, the same P3/SL-HE combination was assessed on two breast cancer cell lines: BT-474, a hormonally positive cell line, and MDA-MB-231, an aggressive triple-negative cell line. The results demonstrated that the 1:8 molar ratio of P3/SL-HE synergistically enhances the anticancer effects against both tumorigenic breast cell lines. Mechanistic studies indicate the activation of an intrinsic apoptotic cell death mechanism through an increase in reactive oxygen species and mitochondrial dysfunction and a secondary programmed necrotic pathway that involves pore formation in the plasma membrane. When a fibroblast cell line, CCD1065SK HDF, was utilized to determine selectivity, the synergistic SL-HE/P3 combination exhibited a protective property compared to the use of SL-HE alone and therefore afforded vastly improved selectivity indices. Given the promising results reported herein, the synergistic combination of P3/SL-HE constitutes a novel strategy that merits further study for the treatment of breast cancer.

Chrysophanol Induces Cell Death and Inhibits Invasiveness through Alteration of Calcium Levels in HepG2 Human Liver Cancer Cells

OBJECTIVE

To investigate the effect of chrysophanol, a phytochemical derived from Radix et Rhizoma Rhei on HepG2 liver cancer cells.

METHODS

HepG2 cell line was treated with different concentrations chrysophanol (0-100 μmol/L) for 24 h. The cell counting kit 8 assay was employed to assess cell viability. Intracellular calcium levels were examined using Fluo-4 AM and Mag-fluo-4 AM staining, followed by flow cytometry analysis. Mitochondrial membrane potential was measured with JC-1 assay kit. Additionally, the expressions of key proteins such as p-JNK, Bax, cytochrome c (Cyt C), cleaved caspase-3 (cCaspase-3), and caspase-8 were analyzed by Western blot. The inhibitory effects of chrysophanol on the invasion of cells were determined using a Transwell assay. Analysis of invasiveness was conducted by wound healing assay.

RESULTS

Chrysophanol significantly reduced the proliferation of HepG2 liver cancer cells by affecting intracellular calcium distribution, diminishing mitochondrial membrane potential, and enhancing the expressions of p-JNK, Bax, Cyt C, cCaspase-3, and caspase-8 in the groups treated with 75 or 100 μmol/L chrysophanol compared to the control group (P<0.05). Additionally, 75 and 100 μmol/L chrysophanol exhibited inhibitory effects on cell migration and wound healing.

CONCLUSION

Chrysophanol demonstrates potential against HepG2 liver cancer cells, suggesting its potential use as a therapeutic agent for liver cancer treatment.

What It Takes To Be a Platelet: Evolving Concepts in Platelet Production

Platelets are among the most abundant cells within the circulation. Given that the platelet lifespan is 7 to 10 days in humans, a constant production of around 100 billion platelets per day is required. Platelet production from precursor cells called megakaryocytes is one of the most enigmatic processes in human biology. Although it has been studied for over a century, there is still controversy about the exact mechanisms leading to platelet release into circulation. The formation of proplatelet extensions from megakaryocytes into bone marrow sinusoids is the best-described mechanism explaining the origin of blood platelets. However, using powerful imaging techniques, several emerging studies have recently raised challenging questions in the field, suggesting that small platelet-sized structures called buds might also contribute to the circulating platelet pool. How and whether these structures differ from microvesicles or membrane blebs, which have previously been described to be released from megakaryocytes, is still a matter of discussion. In this review, we will summarize what the past and present have revealed about platelet production and whether mature blood platelets might emerge via different mechanisms.