Molecular definitions of cell death subroutines: recommendations of the Nomenclature Committee on Cell Death 2012

Vitamin U prevents valproic acid-induced liver injury through supporting enzymatic antioxidant system and increasing hepatocyte proliferation triggered by inflammation and apoptosis

The aim of this study was to investigate the cellular mechanisms that cause valproic acid (VPA)-induced liver damage and the therapeutic effect of Vitamin U (Vit U) on these mechanisms. Female Sprague Dawley rats were randomly divided into four groups: intact control animals, animals that received Vit U (50 mg/kg/day), animals given VPA (500 mg/kg/day), and animals given both VPA and Vit U. The rats in the Vit U + VPA group were administered Vit U by gavage an hour before VPA administration every day for 15 days. Liver tissues were evaluated through histopathological, biochemical, immunohistochemical, and Western blotting techniques. Administration of Vit U with VPA resulted in (i) prevention of histopathological changes caused by VPA; (ii) blockage of the decrease in catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), and superoxide dismutase (SOD) activities; prevention of the elevation in gamma-glutamyl transferase (GGT) activity and advanced oxidation protein products (AOPP) level; (iii) increased in the levels of interleukin-1 beta (IL-1β), active caspase-3, and cytoplasmic cytochrome c; (iv) increase in cleaved poly (ADP-ribose) polymerase (PARP) level and decrease in LC3B (II/I) ratio; (v) increase in the number of proliferating cells nuclear antigen (PCNA) positive hepatocytes. These findings show that Vit U prevents liver damage caused by VPA through increasing the antioxidant enzyme capacity and hepatocyte proliferation by triggering inflammation and apoptosis. These findings suggest that Vit U provides its protective effects against VPA-induced liver damage by stimulating homeostasis and regeneration.

The Ageing Brain: Molecular and Cellular Basis of Neurodegeneration

Ageing is an inevitable event in the lifecycle of all organisms, characterized by progressive physiological deterioration and increased vulnerability to death. Ageing has also been described as the primary risk factor of most neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and frontotemporal lobar dementia (FTD). These neurodegenerative diseases occur more prevalently in the aged populations. Few effective treatments have been identified to treat these epidemic neurological crises. Neurodegenerative diseases are associated with enormous socioeconomic and personal costs. Here, the pathogenesis of AD, PD, and other neurodegenerative diseases has been presented, including a summary of their known associations with the biological hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, cellular senescence, deregulated nutrient sensing, stem cell exhaustion, and altered intercellular communications. Understanding the central biological mechanisms that underlie ageing is important for identifying novel therapeutic targets for neurodegenerative diseases. Potential therapeutic strategies, including the use of NAD+ precursors, mitophagy inducers, and inhibitors of cellular senescence, has also been discussed.

Quantitative tracking of endoplasmic reticulum viscosity during ferroptosis by an iridium complex via TPPLM

Herein, we report a neutral iridium complex, [Ir(4-(2-pyridinyl)benzaldehyde)2(acetylacetone)] (Ir-ER), with viscosity-responsive phosphorescent emission intensity and lifetime. Quantitative measurement by two-photon phosphorescent lifetime imaging shows that the viscosity of ER increases significantly in the process of erastin-induced ferroptosis. Our work provides an effective strategy for quantitative measurement of the micro-environmental alternations of subcellular organelles during a specific cell death process.

Salvianolic acid B attenuates oxidative stress-induced injuries in enterocytes by activating Akt/GSK3β signaling and preserving mitochondrial function

The cellular and tissue damage induced by oxidative stress (OS) contribute to a variety of human diseases, which include gastrointestinal diseases. Salvianolic acid B (Sal B), which is a natural polyphenolic acid in Salvia miltiorrhiza, exhibits prominent antioxidant properties. However, its precise function and molecular mechanisms in protecting normal intestine epithelium from OS-induced damage are still poorly defined. In this study, we tried to clarify this relationship. Here, we found Sal B addiction in the rat intestinal epithelial cell, IEC-6, prevented H₂O₂-induced cell viability decrease and apoptosis induction, ameliorated H₂O₂-induced intestinal epithelial barrier dysfunction and mitochondrial dysfunction, and suppressed H₂O₂-induced production of ROS to varying degrees, ranging from 10% to 30%. Moreover, by employing an ischemia reperfusion model of rats, we also discovered that Sal B treatment reversed ischemia and a reperfusion-caused decrease in villus height and crypt depth, decreased proliferation of enterocytes, and increased the apoptotic index in the jejunum and ileum. Mechanistically, Sal B treatment up-regulated the phosphorylated level of Akt and GSK3β in enterocytes in vitro and in vivo, and PI3K inhibitor LY294002 treatment abrogated the protective effects of Sal B. Meanwhile, the inactivation of GSK3β reversed the oxidative stress-induced apoptosis and mitochondrial dysfunction in IEC-6 cells. Together, our results demonstrated that the damage of intestinal epithelial cells in in vitro and in vivo models were both attenuated by Sal B treatment, and such antioxidant activity might very possibly be attributed to the activation of Akt/GSK3β signaling.

G6PD inhibits ferroptosis in hepatocellular carcinoma by targeting cytochrome P450 oxidoreductase

Ferroptosis is an important cell necrosis and has been a focus in cancer related research.Increcsing studies have focused on the phenotype and function of ferroptosis in tumorigenesis, but the underlying mechanism remains poorly understood. Here, we used bioinformatics approaches to identify differentially expressed genes associated with HCC and ferroptosis. We found that G6PD (glucose-6-phosphate dehydrogenase) was highly expressed in HCC and was associated with poor prognosis. G6PD promoted the proliferation, migration and invasion, as well as inhibited ferroptosis in HCC cells. Pathway and functional enrichment analyses revealed that G6PD was related to the P450 metabolic pathway. POR (cytochrome P450 oxidoreductase) was downregulated in HCC and was significantly correlated with the prognosis. G6PD inhibited ferroptosis inin HCC cells through POR. Knockdown of G6PD reduced the tumor volume and tumor weight in vivo. Our study demonstrated that G6PD deficiency suppresses cell growth, metastasis, and tumorigenesis via upregulating POR, suggesting that G6PD may be used as a biomarker for the treatment of HCC in the future.

Mast Cells and the Pancreas in Human Type 1 and Type 2 Diabetes

Mast cells are highly differentiated, widely distributed cells of the innate immune system, that are currently considered as key regulators of both innate and adaptive immunity. Mast cells play a key role in health and survival mechanisms, especially as sentinel cells that can stimulate protective immune responses. On the other hand, it has been shown that mast cells are involved in the pathogenesis of several diseases, and recently a possible pathogenetic role of mast cells in diabetes has been proposed. In this review we summarize the evidence on the increased presence of mast cells in the pancreas of subjects with type 1 diabetes, which is due to the autoimmune destruction of insulin secreting beta cells, and discuss the differences with type 2 diabetes, the other major form of diabetes. In addition, we describe some of the pathophysiological mechanisms through which mast cells might exert their actions, which could be targeted to potentially protect the beta cells in autoimmune diabetes.

Neutrophil Extracellular Traps: A New Player in Cancer Metastasis and Therapeutic Target

Neutrophil Extracellular Traps (NETs) are neutrophil-derived extracellular scaffolds, which typically consist of fibrous decondensed chromatins decorated with histones and granule proteins. Initially discovered as a host defence mechanism of neutrophil against pathogens, they have also been implicated in the progression of sterile inflammation-associated diseases such as autoimmune disease, diabetes, and cancer. In this review, we highlight and discuss the more recent studies on the roles of NETs in cancer development, with a special focus on cancer metastasis. Moreover, we present the strategies for targeting NETs in pre-clinical models, but also the challenging questions that need to be answered in the field.

Atractylenolide I Inhibits NLRP3 Inflammasome Activation in Colitis-Associated Colorectal Cancer via Suppressing Drp1-Mediated Mitochondrial Fission

Inflammatory bowel disease (IBD) is an important high-risk factor that promotes the occurrence and development of colon cancer. Research on the mechanism of regulating NLRP3 can provide potential targets for treating NLRP3 inflammasome–related diseases and changing the inflammatory potential of immune cells. In this study, the effects of atractylenolide I on colitis-associated CRC (caCRC) and inflammasome activation were investigated both in vivo and in vitro. Furthermore, the role of atractylenolide I on Drp1-mediated mitochondrial fission was analyzed via Western blotting and transmission electron microscopy (TEM). Moreover, the Drp1 overexpression lentiviral vector was used to study the role of Drp1 on the signaling mechanisms of atractylenolide I. Atractylenolide I treatment significantly reduced the cell viability of human HCT116 and SW480 cells and induced apoptosis, and effectively inhibited colon tumors in the AOM/DSS mouse model. The reduction of NLRP3 inflammasome activation and excessive fission of mitochondria mediated by Drp1 were associated with the administration of atractylenolide I. Upregulation of Drp1 reversed the inhibitory effect of atractylenolide I on the activation of NLRP3 inflammasomes. Overexpressing the Drp1 expression counteracted the restraint of atractylenolide I on the release of IL-1β of LPS/DSS-stimulated BMDMs. Atractylenolide I inhibited NLRP3 and caspase-1 expression in mice BMDMs, with no influence in the Drp1-overexpressed BMDMs. These results demonstrated that atractylenolide I inhibits NLRP3 inflammasome activation in colitis-associated colorectal cancer via suppressing Drp1-mediated mitochondrial fission.

Epimedokoreanin C, a prenylated flavonoid isolated from Epimedium koreanum, induces non-apoptotic cell death with the characteristics of methuosis in lung cancer cells

Methuosis is a novel type of non-apoptotic cell death characterized by accumulation of cytoplasmic vacuoles. Identification of molecules that induce methuosis may provide alternative therapeutics for cancers that are refractory to apoptosis. Epimedokoreanin C (EKC) is a prenylated flavonoid isolated from a Chinese herb Epimedium koreanum. In this article, we described that EKC reduced cell viability accompanied by extreme vacuolation in human lung cancer cells. The EKC-induced cell death was clarified as non-apoptosis based on the absence of apoptotic changes. The vacuoles stimulated by EKC were supposed to be derived from macropinocytosis based on the engulfment of extracellular fluid tracer, Lucifer Yellow. The vacuoles acquired some characteristics of late endosomes supported that EKC-induced cell death could be described as methuosis. Rac1 and Arf6 were found to be regulated inversely after EKC treatment. Blocking Rac1 activation with the specific Rac1 inhibitor EHT 1864 prevented the accumulation of vacuoles induced by EKC markedly, suggested that the regulation of Rac1 and Arf6 was at least partial mechanism involved in EKC induced methuosis. EKC synergized the effects of doxorubicin and etoposide, demonstrating the effectiveness of using EKC to synergize conventional chemotherapy. Collectively, EKC was demonstrated as a methuosis-like cell death inducer in lung cancer NCI-H292 and A549 cells. It has the potential to be used as an attractive prototype for developing drugs that could kill apoptosis-resistant cancer cells.

Evasion of the Host Immune Response by Betaherpesviruses

The human immune system boasts a diverse array of strategies for recognizing and eradicating invading pathogens. Human betaherpesviruses, a highly prevalent subfamily of viruses, include human cytomegalovirus (HCMV), human herpesvirus (HHV) 6A, HHV-6B, and HHV-7. These viruses have evolved numerous mechanisms for evading the host response. In this review, we will highlight the complex interplay between betaherpesviruses and the human immune response, focusing on protein function. We will explore methods by which the immune system first responds to betaherpesvirus infection as well as mechanisms by which viruses subvert normal cellular functions to evade the immune system and facilitate viral latency, persistence, and reactivation. Lastly, we will briefly discuss recent advances in vaccine technology targeting betaherpesviruses. This review aims to further elucidate the dynamic interactions between betaherpesviruses and the human immune system.

M2 Muscarinic Receptor Activation Impairs Mitotic Progression and Bipolar Mitotic Spindle Formation in Human Glioblastoma Cell Lines

Background: Glioblastoma multiforme (GBM) is characterized by several genetic abnormalities, leading to cell cycle deregulation and abnormal mitosis caused by a defective checkpoint. We previously demonstrated that arecaidine propargyl ester (APE), an orthosteric agonist of M2 muscarinic acetylcholine receptors (mAChRs), arrests the cell cycle of glioblastoma (GB) cells, reducing their survival. The aim of this work was to better characterize the molecular mechanisms responsible for this cell cycle arrest. Methods: The arrest of cell proliferation was evaluated by flow cytometry analysis. Using immunocytochemistry and time-lapse analysis, the percentage of abnormal mitosis and aberrant mitotic spindles were assessed in both cell lines. Western blot analysis was used to evaluate the modulation of Sirtuin2 and acetylated tubulin—factors involved in the control of cell cycle progression. Results: APE treatment caused arrest in the M phase, as indicated by the increase in p-HH3 (ser10)-positive cells. By immunocytochemistry, we found a significant increase in abnormal mitoses and multipolar mitotic spindle formation after APE treatment. Time-lapse analysis confirmed that the APE-treated GB cells were unable to correctly complete the mitosis. The modulated expression of SIRT2 and acetylated tubulin in APE-treated cells provides new insights into the mechanisms of altered mitotic progression in both GB cell lines. Conclusions: Our data show that the M2 agonist increases aberrant mitosis in GB cell lines. These results strengthen the idea of considering M2 acetylcholine receptors a novel promising therapeutic target for the glioblastoma treatment.

Targeting autophagy in neurodegenerative diseases: From molecular mechanisms to clinical therapeutics

Many neurodegenerative diseases are associated with pathological aggregation of proteins in neurons. Autophagy is a natural self-cannibalization process that can act as a powerful mechanism to remove aged and damaged organelles as well as protein aggregates. It has been shown that promoting autophagy can attenuate or delay neurodegeneration by removing protein aggregates. In this paper, we will review the role of autophagy in Alzheimer's disease (AD), Parkinson's Disease (PD), and Huntington's Disease (HD) and discuss opportunities and challenges of targeting autophagy as a potential therapeutic avenue for treatment of these common neurodegenerative diseases.

Discovery of 1,3,4,5-tetrasubstituted pyrazoles as anti-trypanosomatid agents: Identification of alterations in flagellar structure of L. amazonensis

Trypanosoma cruzi and Leishmania species are causative agents of Chagas disease and Leishmaniasis, respectively, known as Neglected Tropical Diseases. Up to now, the treatments are inadequate and based on old drugs. Thus, we report herein the discovery of 1,3,4,5-tetrasubstituted pyrazole derivatives that presented potent and selective inhibition against promastigote forms of L. amazonensis, and epimastigote forms of T. cruzi. The structure-activity relationship led to the identification of three compounds (2m, 2n and 2p) with an in vitro IC₅₀ of 7.4 µM (selective index - SI ≥ 133.0), 3.8 µM (SI in the range of 148.4 to 200.8), and 7.3 µM (SI in the range of 87.2 to 122.4) against L. amazonensis, respectively. Also, those compounds exhibited in vitro IC₅₀ of 9.7 µM (SI ≥ 101.5), 4.5 µM (SI in the range of 125.3 to 169.6) and 17.1 µM (SI in the range of 37.2 to 52.2) against T. cruzi, respectively. A preliminary study about the reaction mechanism in promastigotes showed that 2n caused an increase of the production of ROS and of lipid storage bodies. Furthermore, 2n induced abnormalities in the flagellum that may have an impact on the parasite motility.

Necrosulfonamide reverses pyroptosis-induced inhibition of proliferation and differentiation of osteoblasts through the NLRP3/caspase-1/GSDMD pathway

The acute inflammatory stimulation occurring after a bone fracture regulates the repair and healing of local bone injury; however, under certain conditions, pyroptosis may occur in osteoblasts, which affects osteoblast proliferation and differentiation, thereby affecting the growth, development and morphological changes of bone tissue. The aim of the present study was to examine the effect of the pyroptosis inhibitor necrosulfonamide (NSA) on the proliferation and differentiation of osteoblasts and elucidate the underlying mechanism. The results revealed that NSA reversed the effects of ATP/lipopolysaccharide (LPS) on cell viability and pyroptosis, and on the mRNA and protein expression of pyroptosis-related genes. It also suppressed the secretion of IL-6, TNF-α and IL-1β and reversed the effects of ATP/LPS on the activity of ALP and the mRNA expression of differentiation-related genes in osteoblasts. The fact that overexpression of caspase-1, gasdermin D (GSDMD) and NLRP3 abolished the effects of NSA on the viability and pyroptosis of osteoblasts, as well as the mRNA expression of differentiation-related genes and the activity of ALP in osteoblasts, indicated that NSA promoted the proliferation and differentiation of osteoblasts by inhibiting the NLRP3/caspase-1/GSDMD pyroptosis pathway. The present study provides proof supporting the potential application of NSA for improving the function of osteoblasts in fracture repair and indicates the value of the NLRP3/caspase-1/GSDMD pyroptosis pathway as a pharmaceutical target.

Rational design of genetically encoded reporter genes for optical imaging of apoptosis

Apoptosis is a process in which cells are genetically regulated to cause a series of changes in morphology and metabolic activity, which ultimately lead to cell death. Apoptosis plays a vital role in the entire life cycle of an organism. Too much or too little apoptosis can cause a variety of diseases. Therefore, efficient and convenient methods for detecting apoptosis are necessary for clinical treatment and drug development. Traditional methods for detecting apoptosis may cause damage to the body during sample collection, such as for flow cytometry analysis. So it is necessary to monitor apoptosis without invasion in vivo. Optical imaging technique provides a more sensitive and economical way for apoptosis visualization. A subset of engineered reporter genes based on fluorescent proteins or luciferases are currently developed to monitor the dynamic changes in apoptotic markers, such as activation of caspases and exposure of phosphatidylserine on the surface of dying cells. These reporters detect apoptosis when cells have not undergone significant morphological changes, providing conditions for early diagnosis of tumors. In addition, these reporters show considerable value in high-throughput screening of apoptosis-related drugs and evaluation of their efficacy in treating tumors. In this review, we will discuss the recent research progress in the optical imaging of apoptosis based on the genetically encoded reporter genes.

Flow cytometric detection of hyper-polarized mitochondria in regulated and accidental cell death processes

Shikonin induced necroptosis in Jurkat cells were identified flow cytometrically by the up-regulation of RIP3 in live cells and that a proportion of these cells underwent other forms of regulated cell death (RCD) which included parthanatos (< 10%), or cleaved PARP (< 10%) and DNA Damage (> 30%). Live necroptotic cells also possessed functioning mitochondria with hyper-polarized mitochondria membrane potential and generated a fivefold increase in cellular reactive oxygen species (ROS) which was resistant to inhibition by zVAD and necrostatin-1 (Nec-1). After loss of plasma membrane integrity these dead necroptotic cells then showed a higher incidence of parthanatos (> 40%), or cleaved PARP (> 15%) but less DNA Damage (< 15%). Inhibition of shikonin induced apoptosis and necroptosis by zVAD and Nec-1 respectively resulted in live necroptotic cells with an increased incidence of cleaved PARP and reduced levels of DNA Damage respectively. Dead necroptotic cells then showed a reduced incidence of parthanatos and DNA Damage after inhibition by zVAD and Nec-1 respectively. A high proportion of these dead necroptotic cells (30%) which lacked plasma membrane integrity also displayed functioning hyper-polarized mitochondria with high levels of cellular ROS and thus had the capacity to influence the outcome of RCD processes rather than just been the end product of cell death, the necrotic cell. Flow cytometry can thus measure multiple forms of RCD and the level of cellular ROS and MMP which highlights the inter-connection between cell death processes and that a single cell may simultaneously display multiple forms of RCD.

Ferroptosis and Its Multifaceted Roles in Cerebral Stroke

Ferroptosis is a unique regulated cell death defined by the intracellular iron overload and distinct biological features compared with other well-known programmed cell death. Ferroptosis can be triggered by many causes including decreased expression of glutathione (GSH), inhibition of the function of glutathione-dependent peroxidase 4 (GPX4), and system x_c^–, all of which finally lead to the over-accumulation of lipid peroxides in the cell. Ferroptosis has been reported to play an important role in the pathophysiological process of various cancers. In recent years, much evidence also proved that ferroptosis is involved in the progress of cerebral stroke. In this review, we summarized the characteristics of ferroptosis and the potential relationship between ferroptosis and ischemic and hemorrhagic stroke, to provide new targets and ideas for the therapy of stroke.

Therapy-Induced Tumor Cell Death: Friend or Foe of Immunotherapy?

Combinatory treatments using surgery, radiotherapy and/or chemotherapy together with immunotherapy have shown encouraging results for specific subsets of tumors, but a significant proportion of tumors remains unsusceptible. Some of these inconsistencies are thought to be the consequence of an immunosuppressive tumor microenvironment (TME) caused by therapy-induced tumor cell death (TCD). An increased understanding of the molecular mechanisms governing TCD has provided valuable insights in specific signaling cascades activated by treatment and the subsequent effects on the TME. Depending on the treatment variables of conventional chemo-, radio- and immunotherapy and the genetic composition of the tumor cells, particular cell death pathways are activated. Consequently, TCD can either have tolerogenic or immunogenic effects on the local environment and thereby affect the post-treatment anti-tumor response of immune cells. Thus, identification of these events can provide new rationales to increase the efficacy of conventional therapies combined with immunotherapies. In this review, we sought to provide an overview of the molecular mechanisms initiated by conventional therapies and the impact of treatment-induced TCD on the TME. We also provide some perspectives on how we can circumvent tolerogenic effects by adequate treatment selection and manipulation of key signaling cascades.

Mechanisms of Regulated Cell Death: Current Perspectives

Balancing cell survival and cell death is fundamental to development and homeostasis. Cell death is regulated by multiple interconnected signaling pathways and molecular mechanisms. Regulated cell death (RCD) is implicated in fundamental processes such as organogenesis and tissue remodeling, removal of unnecessary structures or cells, and regulation of cell numbers. RCD can also be triggered by exogenous perturbations of the intracellular or extracellular microenvironment when the adaptive processes that respond to stress fail. During the past few years, many novel forms of non-apoptotic RCD have been identified, and the characterization of RCD mechanisms at a molecular level has deepened our understanding of diseases encountered in human and veterinary medicine. Given the complexity of these processes, it has become clear that the identification of RCD cannot be based simply on morphologic characteristics and that descriptive and diagnostic terms presently used by pathologists-such as individual cell apoptosis or necrosis-appear inadequate and possibly misleading. In this review, the current understanding of the molecular machinery of each type of non-apoptotic RCD mechanisms is outlined. Due to the continuous discovery of new mechanisms or nuances of previously described processes, the limitations of the terms apoptosis and necrosis to indicate microscopic findings are also reported. In addition, the need for a standard panel of biomarkers and functional tests to adequately characterize the underlying RCD and its role as a mechanism of disease is considered.

Pt(II)-Thiocarbohydrazone Complex as Cytotoxic Agent and Apoptosis Inducer in Caov-3 and HT-29 Cells through the P53 and Caspase-8 Pathways

In this study, a platinum(II) complex ([Pt(H₂L)(PPh₃)] complex) containing a thiocarbohydrazone as the ligand was tested as an anti-proliferative agent against ovarian adenocarcinoma (Caov-3) and human colorectal adenocarcinoma (HT-29) through MTT assays. Apoptotic markers were tested by the AO/PI double staining assay and DNA fragmentation test. Flow cytometry was conducted to measure cell cycle distribution, while the p53 and caspase-8 pathways were tested via immunofluorescence assay. Results demonstrated that the cytotoxic effect of the Pt(II)-thiocarbohydrazone complexes against Caov-3 and HT-29 cells was highly significant, and this effect triggered the activation of the p53 and caspase-8 pathways. Besides, apoptosis stimulated by the Pt(II)-thiocarbohydrazone complex was associated with cell cycle arrest at the G0/G1 phase. These findings suggest that the target complex inhibited the proliferation of Caov-3 and HT-29 cells, resulting in the arrest of the cell cycle and induction of apoptosis via the stimulation of the p53 and caspase-8 pathways. The present data suggests that the Pt(II)-thiocarbohydrazone complex could also be a promising chemotherapeutic agent for other types of cancer cells.

Syncytiotrophoblast stress in early onset preeclampsia: The issues perpetuating the syndrome

Preeclampsia is a pregnancy-specific syndrome characterized by a sudden increase in blood pressure accompanied by proteinuria and/or maternal multi-system damage associated to poor fetal outcome. In early-onset preeclampsia, utero-placental perfusion is altered, causing constant and progressive damage to the syncytiotrophoblast, generating syncytiotrophoblast stress. The latter leads to the detachment and release of syncytiotrophoblast fragments, anti-angiogenic factors and pro-inflammatory molecules into maternal circulation, resulting in the emergence and persistence of the characteristic symptoms of this syndrome during pregnancy. Therefore, understanding the origin and consequences of syncytiotrophoblast stress in preeclampsia is vital to develop new therapeutic alternatives, focused on reducing the burden of this syndrome. In this review, we describe five central characteristics of syncytial stress that should be targeted or prevented in order to reduce preeclampsia symptoms: histological alterations, syncytiotrophoblast damage, antiangiogenic protein export, placental deportation, and altered syncytiotrophoblast turnover. Therapeutic management of these characteristics may improve maternal and fetal outcomes.

Small-molecule inhibition of APE1 induces apoptosis, pyroptosis, and necroptosis in non-small cell lung cancer

Apurinic/apyrimidinic endonuclease 1 (APE1) plays a critical role in the base excision repair (BER) pathway, which is responsible for the excision of apurinic sites (AP sites). In non-small cell lung cancer (NSCLC), APE1 is highly expressed and associated with poor patient prognosis. The suppression of APE1 could lead to the accumulation of unrepaired DNA damage in cells. Therefore, APE1 is viewed as an important marker of malignant tumors and could serve as a potent target for the development of antitumor drugs. In this study, we performed a high-throughput virtual screening of a small-molecule library using the three-dimensional structure of APE1 protein. Using the AP site cleavage assay and a cell survival assay, we identified a small molecular compound, NO.0449-0145, to act as an APE1 inhibitor. Treatment with NO.0449-0145 induced DNA damage, apoptosis, pyroptosis, and necroptosis in the NSCLC cell lines A549 and NCI-H460. This inhibitor was also able to impede cancer progression in an NCI-H460 mouse model. Moreover, NO.0449-0145 overcame both cisplatin- and erlotinib-resistance in NSCLC cell lines. These findings underscore the importance of APE1 as a therapeutic target in NSCLC and offer a paradigm for the development of small-molecule drugs that target key DNA repair proteins for the treatment of NSCLC and other cancers.

Apoptosis is not conserved in plants as revealed by critical examination of a model for plant apoptosis-like cell death

BACKGROUND

Animals and plants diverged over one billion years ago and evolved unique mechanisms for many cellular processes, including cell death. One of the most well-studied cell death programmes in animals, apoptosis, involves gradual cell dismantling and engulfment of cellular fragments, apoptotic bodies, through phagocytosis. However, rigid cell walls prevent plant cell fragmentation and thus apoptosis is not applicable for executing cell death in plants. Furthermore, plants are devoid of the key components of apoptotic machinery, including phagocytosis as well as caspases and Bcl-2 family proteins. Nevertheless, the concept of plant "apoptosis-like programmed cell death" (AL-PCD) is widespread. This is largely due to superficial morphological resemblances between plant cell death and apoptosis, and in particular between protoplast shrinkage in plant cells killed by various stimuli and animal cell volume decrease preceding fragmentation into apoptotic bodies.

RESULTS

Here, we provide a comprehensive spatio-temporal analysis of cytological and biochemical events occurring in plant cells subjected to heat shock at 40-55 °C and 85 °C, the experimental conditions typically used to trigger AL-PCD and necrotic cell death, respectively. We show that cell death under both conditions was not accompanied by membrane blebbing or formation of apoptotic bodies, as would be expected during apoptosis. Instead, we observed instant and irreversible permeabilization of the plasma membrane and ATP depletion. These processes did not depend on mitochondrial functionality or the presence of Ca2+ and could not be prevented by an inhibitor of ferroptosis. We further reveal that the lack of protoplast shrinkage at 85 °C, the only striking morphological difference between cell deaths induced by 40-55 °C or 85 °C heat shock, is a consequence of the fixative effect of the high temperature on intracellular contents.

CONCLUSIONS

We conclude that heat shock-induced cell death is an energy-independent process best matching definition of necrosis. Although the initial steps of this necrotic cell death could be genetically regulated, classifying it as apoptosis or AL-PCD is a terminological misnomer. Our work supports the viewpoint that apoptosis is not conserved across animal and plant kingdoms and demonstrates the importance of focusing on plant-specific aspects of cell death pathways.

Abscisic Acid-Induced Autophagy Selectively via MAPK/JNK Signalling Pathway in Glioblastoma

As a widely known plant hormone, Abscisic acid plays an important role in the progress of planting cell and their stress response. Recently, we reported that ABA might play an anti-cancer role in glioma tissues. In the present study, the molecular mechanism of ABA anti-cancer was further explored in glioblastoma cells. By measuring LC3 puncta formation and conversion in glioblastoma cells, inhibiting the autophagic pathway, targeting the essential autophagic modulator beclin 1 with RNA interference, and analysing cellular morphology via transmission electron microscopy, we found that ABA-treated glioblastoma cells exhibited the features of autophagy. Specifically, ABA-induced autophagy in glioblastoma cells was mediated by the MAPK/JNK signalling pathway rather than the PI3K/AKT/mTOR axis. Moreover, the inhibition or knockdown of JNK specifically blocked ABA-induced autophagic cell death. ABA-induced autophagy was further confirmed in tumour-bearing mice and was accompanied by the inhibition of glioma growth in vivo. This report is the first to describe autophagy induced by ABA and mediated by the MAPK/JNK pathway in human cancer cells and tumour-bearing mice. These results may shed some light in new therapeutic strategies of glioma.

Statistically optimized pentazocine loaded microsphere for the sustained delivery application: Formulation and characterization

Pentazocine (PTZ) is a narcotic analgesic used to manage moderate to severe, acute and chronic pains. In this study, PTZ loaded Ethyl cellulose microsphere has been formulated for sustained release and improved bioavailability of PTZ. These microspheres were fabricated by oil in water emulsion solvent evaporation technique. A three factorial, three levels Box-Behnken design was applied to investigate the influence of different formulation components and process variables on the formulation response using the numeric approach through the design expert^® software. All the formulations were characterized for the morphology, different physicochemical properties and the results were supported with the ANOVA analysis, three dimensional contour graphs and regression equations. The maximum percentage yield was 98.67% with 98% entrapment of PTZ. The mean particle size of the formulations ranges from 50–148μm, which directly relates to the concentration of polymer and inversely proportional to the stirring speed. SEM revealed the spherical shape of PTZ microspheres with porous structures. These are physically, chemically and thermally stable as confirmed through Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD) and thermal gravimetric (TG) analysis respectively. The microspheres provided a sustained release of the PTZ for more than 12 hours, following zero order with fickian and non fickian diffusion. The results indicate that prepared microspheres can be a potential drug delivery system (DDS) for the delivery of PTZ in the management of pains.

[A trio of mechanisms involved in regeneration initiation in animals]

Whole-body and complex structure regeneration is a widespread phenomenon in animals. While regenerative abilities vary greatly from one species to another, a number of mechanisms appear essential for regeneration in distantly related phylogenetic groups. In this review, we synthetize the knowledge gathered on the implication of three mechanisms that appear to be important for the initiation of regeneration in animals. Reactive Oxygen Species (ROS) are metabolic by-products involved in cell signalling, which are produced shortly after amputation in several species. ROS production may be responsible for triggering apoptosis, another recurring mechanism involved in regeneration initiation. In turn, apoptosis causes compensatory proliferation by setting off cellular division, thus contributing to the reconstitution of tissues. Inhibiting either ROS production, apoptosis or cellular proliferation impairs regeneration in a variety of model species.

Ruthenium (II)/allopurinol complex inhibits breast cancer progression via multiple targets

Metal complexes based on ruthenium have established excellent activity with less toxicity and great selectivity for tumor cells. This study aims to assess the anticancer potential of ruthenium(II)/allopurinol complexes called [RuCl₂(allo)₂(PPh₃)₂] (1) and [RuCl₂(allo)₂(dppb)] (2), where allo means allopurinol, PPh₃ is triphenylphosphine and dppb, 1,4-bis(diphenylphosphino)butane. The complexes were synthesized and characterized by elemental analysis, IR, UV-Vis and NMR spectroscopies, cyclic voltammetry, molar conductance measurements, as well as the X-ray crystallographic analysis of complex 2. The antitumor effects of compounds were determined by cytotoxic activity and cellular and molecular responses to cell death mechanisms. Complex 2 showed good antitumor profile prospects because in addition to its cytotoxicity, it causes cell cycle arrest, induction of DNA damage, morphological and biochemical alterations in the cells. Moreover, complex 2 induces cell death by p53-mediated apoptosis, caspase activation, increased Beclin-1 levels and decreased ROS levels. Therefore, complex 2 can be considered a suitable compound in antitumor treatment due to its cytotoxic mechanism.

The Epidermal Growth Factor Ligand Spitz Modulates Macrophage Efferocytosis, Wound Responses and Migration Dynamics During Drosophila Embryogenesis

How multifunctional cells such as macrophages interpret the different cues within their environment and undertake an appropriate response is a key question in developmental biology. Understanding how cues are prioritized is critical to answering this - both the clearance of apoptotic cells (efferocytosis) and the migration toward damaged tissue is dependent on macrophages being able to interpret and prioritize multiple chemoattractants, polarize, and then undertake an appropriate migratory response. Here, we investigate the role of Spitz, the cardinal Drosophila epidermal growth factor (EGF) ligand, in regulation of macrophage behavior in the developing fly embryo, using activated variants with differential diffusion properties. Our results show that misexpression of activated Spitz can impact macrophage polarity and lead to clustering of cells in a variant-specific manner, when expressed either in macrophages or the developing fly heart. Spitz can also alter macrophage distribution and perturb apoptotic cell clearance undertaken by these phagocytic cells without affecting the overall levels of apoptosis within the embryo. Expression of active Spitz, but not a membrane-bound variant, can also increase macrophage migration speeds and impair their inflammatory responses to injury. The fact that the presence of Spitz specifically undermines the recruitment of more distal cells to wound sites suggests that Spitz desensitizes macrophages to wounds or is able to compete for their attention where wound signals are weaker. Taken together these results suggest this molecule regulates macrophage migration and their ability to dispose of apoptotic cells. This work identifies a novel regulator of Drosophila macrophage function and provides insights into signal prioritization and integration in vivo. Given the importance of apoptotic cell clearance and inflammation in human disease, this work may help us to understand the role EGF ligands play in immune cell recruitment during development and at sites of disease pathology.

The potential role of necroptosis in clinical diseases (Review)

As an important type of programmed cell death in addition to apoptosis, necroptosis occurs in a variety of pathophysiological processes, including infections, liver diseases, kidney injury, neurodegenerative diseases, cardiovascular diseases, and human tumors. It can be triggered by a variety of factors, such as tumor necrosis factor receptor and Toll‑like receptor families, intracellular DNA and RNA sensors, and interferon, and is mainly mediated by receptor‑interacting protein kinase 1 (RIP1), RIP3, and mixed lineage kinase domain‑like protein. A better understanding of the mechanism of necroptosis may be useful in the development of novel drugs for necroptosis‑related diseases. In this review, the focus is on the molecular mechanisms of necroptosis, exploring the role of necroptosis in different pathologies, discussing their potential as a novel therapeutic target for disease therapy, and providing suggestions for further study in this area.

Emerging mechanisms and targeted therapy of ferroptosis in cancer

Ferroptosis is an iron- and lipid reactive oxygen species (ROS)-dependent form of programmed cell death that is distinct from other forms of regulatory cell death at the morphological, biological, and genetic levels. Emerging evidence suggests critical roles for ferroptosis in cell metabolism, the redox status, and various diseases, such as cancers, nervous system diseases, and ischemia-reperfusion injury, with ferroptosis-related proteins. Ferroptosis is inhibited in diverse cancer types and functions as a dynamic tumor suppressor in cancer development, indicating that the regulation of ferroptosis can be utilized as an interventional target for tumor treatment. Small molecules and nanomaterials that reprogram cancer cells to undergo ferroptosis are considered effective drugs for cancer therapy. Here, we systematically summarize the molecular basis of ferroptosis, the suppressive effect of ferroptosis on tumors, the effect of ferroptosis on cellular metabolism and the tumor microenvironment (TME), and ferroptosis-inducing agents for tumor therapeutics. An understanding of the latest progress in ferroptosis could provide references for proposing new potential targets for the treatment of cancers.

Mechanisms of Cisplatin-Induced Acute Kidney Injury: Pathological Mechanisms, Pharmacological Interventions, and Genetic Mitigations

Administration of the chemotherapeutic agent cisplatin leads to acute kidney injury (AKI). Cisplatin-induced AKI (CIAKI) has a complex pathophysiological map, which has been linked to cellular uptake and efflux, apoptosis, vascular injury, oxidative and endoplasmic reticulum stress, and inflammation. Despite research efforts, pharmaceutical interventions, and clinical trials spanning over several decades, a consistent and stable pharmacological treatment option to reduce AKI in patients receiving cisplatin remains unavailable. This has been predominately linked to the incomplete understanding of CIAKI pathophysiology and molecular mechanisms involved. Herein, we detail the extensively known pathophysiology of cisplatin-induced nephrotoxicity that manifests and the variety of pharmacological and genetic alteration studies that target them.

Resveratrol inhibits necroptosis by mediating the TNF-α/RIP1/RIP3/MLKL pathway in myocardial hypoxia/reoxygenation injury

Resveratrol (RES) protects myocardial cells from hypoxia/reoxygenation (H/R)-caused injury. However, the mechanism of this effect has not been clarified. Thus, in this study, we aimed to determine whether RES attenuates H/R-induced cell necroptosis by inhibiting the tumor necrosis factor-alpha (TNF-α)/receptor-interacting protein kinase 1 (RIP1)/RIP3/mixed-lineage kinase domain-like (MLKL) signaling pathway. Rat myocardial ischemia/reperfusion (I/R) models and H/R-injured cell models were constructed. Our study showed that myocardial H/R injury significantly increased the levels of TNF-α, RIP1, RIP3, and p-MLKL/MLKL by western blot analysis. Cell viability assay and 4,6-dianmidino-2-phenylindole (DAPI)-propidium iodide staining showed that the cell viability was decreased, and necroptosis was increased after myocardial H/R injury. The expressions of TNF-α, RIP1, RIP3, and p-MLKL/MLKL in H/R myocardial cells treated with different concentrations of RES were significantly downregulated. In addition, we also found that the cell viability was increased and necroptosis was decreased in dose-dependent manners when H/R-injured cells were treated with RES. In addition, the enhanced effect of TNF-α on necroptosis in myocardial H/R-injured cells was improved by RES, and the effect of RES was confirmed in vivo in I/R rats. This study also showed that RES suppresses necroptosis in H9c2 cells, which may occur through the inhibition of the TNF-α/RIP1/RIP3/MLKL signaling pathway. Our data suggest that necroptosis is a promising therapeutic target and may be a promising therapeutic target for the treatment of myocardial I/R injury.

An Overview on the Conservative Management of Endometriosis from a Naturopathic Perspective: Phytochemicals and Medicinal Plants

Background: Endometriosis is a chronic and debilitating disease, which affects millions of young women worldwide. Although medicine has incontestably evolved in the last years, there is no common ground regarding the early and accurate diagnosis of this condition, its pathogenic mechanisms, and curative treatment. Even though the spontaneous resolution of endometriosis is sometimes possible, recent reports suggested that it can be a progressive condition. It can associate chronic pelvic pain, vaginal bleeding, infertility, or malignant degenerescence. Conventional treatments could produce many side effects, and despite treatment, the symptoms may reappear. In recent years, experimental evidence suggested that plant-based medicine could exert beneficial effects on endometriosis and endometriosis-related symptoms. This study aims to highlight the pharmaceutical activity of phytochemicals and medicinal plants against endometriosis and to provide a source of information regarding the alternative treatment of this condition. Methods: For this review, we performed a research using PubMed, GoogleScholar, and CrossRef databases. We selected the articles published between January 2000 and July 2020, written in English. Results: We found 17 medicinal plants and 13 phytochemicals, which have demonstrated their beneficial effects against endometriosis. Several of their biological activities consist of antiangiogenic, anti-inflammatory effects, and oxidative-stress reduction. Conclusion: Medicinal herbs and their bioactive compounds exhibit antiangiogenic, antioxidant, sedative and pain-alleviating properties and the effects recorded until now encourage their use for the conservative management of endometriosis.

The role of melatonin in sarcopenia: Advances and application prospects

Sarcopenia is an age-related disease that has gradually become a serious health problem for elderly individuals. It not only greatly increases the risk of falls, weakness, and disability but also reduces the ability of patients to take care of themselves. Sarcopenia can directly affect the quality of life and disease prognosis of elderly individuals. However, drug interventions for this disease are lacking. Melatonin is a biological hormone produced by the body that has good free radical scavenging effects, antioxidant effects and other effects. It was originally used as a sleep aid and is now being used for an increasing number of new indications. Its effect on sarcopenia has also begun to attract attention. It is currently known that it can protect the mitochondria of skeletal muscle cells, maintain the number of muscle fibres, partially reverse the pathological changes of ageing muscle tissue, and increase muscle strength in patients with sarcopenia. A large number of microRNAs are expressed during cell ageing, that in turn provides a biological background to age-related diseases, like sarcopenia. Increasing studies have found an interaction between melatonin and miRNAs, suggesting that melatonin can be used in the treatment of sarcopenia. The increased expression of inflammation-associated miRNA-483 in elderly patients may be the basis for the age-dependent decrease in melatonin secretion，that may play a role in the morbidity of sarcopenia. Melatonin is closely related to sarcopenia. It has a wide range of effects on sarcopenia and has good application prospects for the prevention and treatment of sarcopenia.

Molecular Action of Polyphenols in Leukaemia and Their Therapeutic Potential

Leukaemia is a malignant disease of the blood. Current treatments for leukaemia are associated with serious side-effects. Plant-derived polyphenols have been identified as potent anti-cancer agents and have been shown to work synergistically with standard chemotherapy agents in leukaemia cell lines. Polyphenols have multiple mechanisms of action and have been reported to decrease cell proliferation, arrest cell cycle and induce apoptosis via the activation of caspase (3, 8 and 9); the loss of mitochondrial membrane potential and the release of cytochrome c. Polyphenols have been shown to suppress activation of transcription factors, including NF-kB and STAT3. Furthermore, polyphenols have pro-oxidant properties, with increasing evidence that polyphenols inhibit the antioxidant activity of glutathione, causing oxidative DNA damage. Polyphenols also induce autophagy-driven cancer cell death and regulate multidrug resistance proteins, and thus may be able to reverse resistance to chemotherapy agents. This review examines the molecular mechanism of action of polyphenols and discusses their potential therapeutic targets. Here, we discuss the pharmacological properties of polyphenols, including their anti-inflammatory, antioxidant, anti-proliferative, and anti-tumour activities, and suggest that polyphenols are potent natural agents that can be useful therapeutically; and discuss why data on bioavailability, toxicity and metabolism are essential to evaluate their clinical use.

RIPK3-Dependent Necroptosis Is Induced and Restricts Viral Replication in Human Astrocytes Infected With Zika Virus

Apoptosis, pyroptosis and necroptosis are regulated processes of cell death which can be crucial for viral disease outcomes in hosts because of their effects on viral pathogenicity and host resistance. Zika virus (ZIKV) is a mosquito-borne flavivirus, which infects humans and can cause neurological disorders. Neural developmental disorders and microcephaly could occur in infected fetuses. Several types of nervous cells have been reported to be susceptible to ZIKV infection. Human astrocytes play important roles in the nutritional support and defense of neurons. In this study, we show that human astrocytes are susceptible to ZIKV infection and undergo progressive cell death after infection. In infected astrocytes we detected no cleavage or activation of pro-caspase-3 and pro-caspase-1. Apoptotic substrates and increased secretion of interleukin (IL)-1β or IL-18 were not detected, either. These ruled out the occurrence of apoptosis or pyroptosis in ZIKV-infected astrocytes. We detected, however, an increase of phosphorylated receptor-interacting serine/threonine-protein kinase (RIPK)1, RIPK3, and mixed lineage kinase domain-like (MLKL) protein, indicating that programmed necrosis, or necroptosis, was induced in infected astrocytes. The phosphorylation and cell death were inhibited in cells pre-treated with GSK’872, an inhibitor of RIPK3, while inhibition of RIPK1 with an inhibitor, Necrostatin-1, had no effect, suggesting that ZIKV-induced necroptosis was RIPK1-independent in astrocytes. Consistent with this finding, the inhibition of RIPK1 had no effect on the phosphorylation of MLKL. We showed evidence that MLKL phosphorylation was RIPK3-dependent and ZBP-1, which could stimulate RIPK3, was upregulated in ZIKV-infected astrocytes. Finally, we demonstrated that in GSK’872-pre-treated astrocytes, viral replication increased significantly, which indicates that necroptosis may be protective against viral replication in astrocytes. Our finding that astrocytes uniquely underwent necroptosis in response to ZIKV infection provides insight and helps us better understand the viral pathogenesis in the ZIKV-infected central nervous system.

Autophagy and senescence in cancer therapy

Tumor cells can undergo diverse responses to cancer therapy. While apoptosis represents the most desirable outcome, tumor cells can alternatively undergo autophagy and senescence. Both autophagy and senescence have the potential to make complex contributions to tumor cell survival via both cell autonomous and cell non-autonomous pathways. The induction of autophagy and senescence in tumor cells, preclinically and clinically, either individually or concomitantly, has generated interest in the utilization of autophagy modulating and senolytic therapies to target autophagy and senescence, respectively. This chapter summarizes the current evidence for the promotion of autophagy and senescence as fundamental responses to cancer therapy and discusses the complexity of their functional contributions to cell survival and disease outcomes. We also highlight current modalities designed to exploit autophagy and senescence in efforts to improve the efficacy of cancer therapy.

Loss of FADD and Caspases Affects the Response of T-Cell Leukemia Jurkat Cells to Anti-Cancer Drugs

Programmed cell death (PCD) pathways play a crucial role in the response of cancer cells to treatment. Their dysregulation is one of the cancer hallmarks and one of the reasons of drug resistance. Here, we studied the significance of the individual members of PCD signaling pathways in response to treatment with common anti-cancer drugs using the T-cell leukemia Jurkat cells with single or double knockouts of necroptosis and/or apoptosis genes. We identified apoptosis as the primary cell death pathway upon anti-cancer drugs treatment. The cells with knocked out either Fas-associated protein with death domain (FADD) or all executioner caspases were resistant. This resistance could be partially overcome by induction of RIP1-dependent necroptosis through TNFR1 activation using combined treatment with TNF-α and smac mimetic (LCL161). RIP1 was essential for cellular response to TNF-α and smac mimetic, but dispensable for the response to anti-cancer drugs. Here, we demonstrated the significance of FADD and executioner caspases in carrying out programmed cell death upon anti-cancer drug treatments and the ability of combined treatment with TNF-α and smac mimetic to partially overcome drug resistance of FADD and/or CASP3/7/6-deficient cells via RIP1-dependent necroptosis. Thus, a combination of TNF-α and smac mimetic could be a suitable strategy for overcoming resistance to therapy in cells unable to trigger apoptosis.

Guidelines for Regulated Cell Death Assays: A Systematic Summary, A Categorical Comparison, A Prospective

Over the past few years, the field of regulated cell death continues to expand and novel mechanisms that orchestrate multiple regulated cell death pathways are being unveiled. Meanwhile, researchers are focused on targeting these regulated pathways which are closely associated with various diseases for diagnosis, treatment, and prognosis. However, the complexity of the mechanisms and the difficulties of distinguishing among various regulated types of cell death make it harder to carry out the work and delay its progression. Here, we provide a systematic guideline for the fundamental detection and distinction of the major regulated cell death pathways following morphological, biochemical, and functional perspectives. Moreover, a comprehensive evaluation of different assay methods is critically reviewed, helping researchers to make a reliable selection from among the cell death assays. Also, we highlight the recent events that have demonstrated some novel regulated cell death processes, including newly reported biomarkers (e.g., non-coding RNA, exosomes, and proteins) and detection techniques.

Transplantation of olfactory ensheathing cells promotes the therapeutic effect of neural stem cells on spinal cord injury by inhibiting necrioptosis

Transplantation of neural stem cells (NSCs) is one of the most promising treatments for spinal cord injury (SCI). However, the limited survival of transplanted NSCs reduces their therapeutic effects. The aim of the present study was to examine whether a co-transplantation of olfactory ensheathing cells (OECs) may enhance the survival of NSCs and improve the beneficial effects of NSCs in rats with SCI, as well as to investigate potential mechanisms underlying such efficacies. Co-transplantation of OECs and NSCs was used to treat rats with SCI. Sympathetic nerve function was determined by measuring sympathetic skin responses. The results showed that OEC/NSC co-transplantation improved motor function and autonomic nerve function in rats with SCI. Co-transplantation of OECs promoted NSC-induced neuroprotection and inhibited programmed necrosis of NSCs, which was mediated by receptor-interacting protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL). Furthermore, OECs increased the proliferation and differentiation of NSCs in vitro, and improved the survival rate of NSCs in vivo. Taken together, we conclude that transplantation of OECs inhibited programmed necrosis of co-transplanted NSCs to promote therapeutic effects on SCI. Therefore, co-transplantation of OECs and NSCs may represent a promising strategy for treating patients with SCI.

Cell Death in Cyanobacteria: Current Understanding and Recommendations for a Consensus on Its Nomenclature

Cyanobacteria are globally widespread photosynthetic prokaryotes and are major contributors to global biogeochemical cycles. One of the most critical processes determining cyanobacterial eco-physiology is cellular death. Evidence supports the existence of controlled cellular demise in cyanobacteria, and various forms of cell death have been described as a response to biotic and abiotic stresses. However, cell death research in this phylogenetic group is a relatively young field and understanding of the underlying mechanisms and molecular machinery underpinning this fundamental process remains largely elusive. Furthermore, no systematic classification of modes of cell death has yet been established for cyanobacteria. In this work, we analyzed the state of knowledge in the field of cyanobacterial cell death. Based on that, we propose unified criterion for the definition of accidental, regulated, and programmed forms of cell death in cyanobacteria based on molecular, biochemical, and morphologic aspects following the directions of the Nomenclature Committee on Cell Death (NCCD). With this, we aim to provide a guide to standardize the nomenclature related to this topic in a precise and consistent manner, which will facilitate further ecological, evolutionary, and applied research in the field of cyanobacterial cell death.

Activation of NRF2/FPN1 pathway attenuates myocardial ischemia-reperfusion injury in diabetic rats by regulating iron homeostasis and ferroptosis

In patients with ischemic heart disease, myocardial ischemia-reperfusion injury (IRI) can aggravate their condition even worse, and diabetes increases their risk of myocardial IRI. Pathological pathways of common diseases and surgical operations like diabetes, obesity, coronary artery angioplasty, and heart transplantation entail disorders of iron metabolism. Ferroportin1 (FPN1) is the only mammalian protein associated with iron release and thus plays a vital role in iron homeostasis, while nuclear factor E2-related factor 2 (NRF2) controls the transcription of FPN1. Since the NRF2/FPN1 pathway may play a favorable role in the therapy of diabetic myocardial IRI, this work investigated the possible mechanism. In this study, we investigated the effects of ferroptosis in STZ-induced diabetic rats following myocardial IRI in vivo, and its alteration in glucose and hypoxia/reoxygenation-induced cardiomyocytes injury in vitro. Rats and H9c2 cardiomyocytes were randomly divided into 6 groups and treated with sulforaphane and erastin besides the establishment of diabetic myocardial IRI and hyperglycemic hypoxia-reoxygenation models. Cardiac functional and structural damage were detected by Evans blue/TTC double staining, echocardiography, HE staining, and serological indices. CCK-8 assay and ROS production were used to measure cardiomyocyte viability and oxidative stress level. Additionally, the changes in cell supernatant levels of Fe2+, SOD, MDA, and mRNA and protein expression of ferroptosis marker proteins confirmed the beneficial effects of the NRF2/FPN1 pathway on diabetic myocardial IRI related to iron metabolism and ferroptosis. Overall, these findings suggest that iron homeostasis-related ferroptosis plays an important role in aggravating myocardial IRI in diabetic rats, and NRF2/FPN1 pathway-mediated iron homeostasis and ferroptosis might be a promising therapeutic target against myocardial IRI in diabetes.

Protein A Modulates Neutrophil and Keratinocyte Signaling and Survival in Response to Staphylococcus aureus

The type 1 TNF-α receptor (TNFR1) has a central role in initiating both pro-inflammatory and pro-apoptotic signaling cascades in neutrophils. Considering that TNFR1 signals Staphylococcus aureus protein A (SpA), the aim of this study was to explore the interaction of this bacterial surface protein with neutrophils and keratinocytes to underscore the signaling pathways that may determine the fate of these innate immune cells in the infected tissue during staphylococcal skin infections. Using human neutrophils cultured in vitro and isogenic staphylococcal strains expressing or not protein A, we demonstrated that SpA is a potent inducer of IL-8 in neutrophils and that the induction of this chemokine is dependent on the SpA-TNFR1 interaction and p38 activation. In addition to IL-8, protein A induced the expression of TNF-α and MIP-1α highlighting the importance of SpA in the amplification of the inflammatory response. Protein A contributed to reduce neutrophil mortality prolonging their lifespan upon the encounter with S. aureus. Signaling initiated by SpA modulated the type of neutrophil cell death in vitro and during skin and soft tissue infections (SSTI) in vivo triggering the apoptotic pathway instead of necrosis. Moreover, SpA induced pro-inflammatory cytokines in keratinocytes, modulating their survival in vitro and preventing the exacerbated necrosis and ulceration of the epithelium during SSTI in vivo. Taken together, these results highlight the importance of the inflammatory signaling induced by protein A in neutrophils and skin epithelial cells. The ability of protein A to modulate the neutrophil/epithelial cell death program in the skin is of clinical relevance considering that lysis of neutrophils and epithelial cells will promote an intense inflammatory response and contribute to tissue damage, a non-desirable feature of complicated SSTI.

Retinal Inflammation, Cell Death and Inherited Retinal Dystrophies

Inherited retinal dystrophies (IRDs) are a group of retinal disorders that cause progressive and severe loss of vision because of retinal cell death, mainly photoreceptor cells. IRDs include retinitis pigmentosa (RP), the most common IRD. IRDs present a genetic and clinical heterogeneity that makes it difficult to achieve proper treatment. The progression of IRDs is influenced, among other factors, by the activation of the immune cells (microglia, macrophages, etc.) and the release of inflammatory molecules such as chemokines and cytokines. Upregulation of tumor necrosis factor alpha (TNFα), a pro-inflammatory cytokine, is found in IRDs. This cytokine may influence photoreceptor cell death. Different cell death mechanisms are proposed, including apoptosis, necroptosis, pyroptosis, autophagy, excessive activation of calpains, or parthanatos for photoreceptor cell death. Some of these cell death mechanisms are linked to TNFα upregulation and inflammation. Therapeutic approaches that reduce retinal inflammation have emerged as useful therapies for slowing down the progression of IRDs. We focused this review on the relationship between retinal inflammation and the different cell death mechanisms involved in RP. We also reviewed the main anti-inflammatory therapies for the treatment of IRDs.

Advantages of targeting the tumor immune microenvironment over blocking immune checkpoint in cancer immunotherapy

Despite great success in cancer immunotherapy, immune checkpoint-targeting drugs are not the most popular weapon in the armory of cancer therapy. Accumulating evidence suggests that the tumor immune microenvironment plays a critical role in anti-cancer immunity, which may result in immune checkpoint blockade therapy being ineffective, in addition to other novel immunotherapies in cancer patients. In the present review, we discuss the deficiencies of current cancer immunotherapies. More importantly, we highlight the critical role of tumor immune microenvironment regulators in tumor immune surveillance, immunological evasion, and the potential for their further translation into clinical practice. Based on their general targetability in clinical therapy, we believe that tumor immune microenvironment regulators are promising cancer immunotherapeutic targets. Targeting the tumor immune microenvironment, alone or in combination with immune checkpoint-targeting drugs, might benefit cancer patients in the future.

Hypoxia-Induced Autophagy Enhances Cisplatin Resistance in Human Bladder Cancer Cells by Targeting Hypoxia-Inducible Factor-1α

Purpose

To investigate the effect of hypoxia on chemoresistance and the underlying mechanism in bladder cancer cells.

Methods

BIU-87 bladder cancer cell line was treated with cisplatin under hypoxic and normoxic conditions and tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, and Western blotting. All the data were expressed as mean ± standard error from three independent experiments and analyzed by multiple t-tests.

Results

Apoptosis of bladder cancer cells caused by cisplatin was attenuated in hypoxic conditions. Hypoxia enhanced autophagy caused by cisplatin. The autophagy inhibitor and HIF-1α inhibitor can reverse the chemoresistance in hypoxic condition. Apoptosis and autophagy of bladder cancer cells were downregulated by HIF-1α inhibitor YC-1. Hypoxia-induced autophagy enhanced chemoresistance to cisplatin via the HIF-1 signaling pathway.

Conclusion

Resistance to cisplatin in BIU-87 bladder cancer cells under hypoxic conditions can be explained by activation of autophagy, which is regulated by HIF-1α-associated signaling pathways. The hypoxia–autophagy pathway may be a target for improving the efficacy of cisplatin chemotherapy in bladder cancer.

Caspase-Independent Regulated Necrosis Pathways as Potential Targets in Cancer Management

Regulated necrosis is an emerging type of cell death independent of caspase. Recently, with increasing findings of regulated necrosis in the field of biochemistry and genetics, the underlying molecular mechanisms and signaling pathways of regulated necrosis are gradually understood. Nowadays, there are several modes of regulated necrosis that are tightly related to cancer initiation and development, including necroptosis, ferroptosis, parthanatos, pyroptosis, and so on. What’s more, accumulating evidence shows that various compounds can exhibit the anti-cancer effect via inducing regulated necrosis in cancer cells, which indicates that caspase-independent regulated necrosis pathways are potential targets in cancer management. In this review, we expand the molecular mechanisms as well as signaling pathways of multiple modes of regulated necrosis. We also elaborate on the roles they play in tumorigenesis and discuss how each of the regulated necrosis pathways could be therapeutically targeted.

Co-treatment with disulfiram and glycyrrhizic acid suppresses the inflammatory response of chondrocytes

Background

Osteoarthritis (OA) is a kind of systemic musculoskeletal disorder and a most important factor for causing disability and physical painfulness. Nevertheless, due to the fact that OA can be triggered by multiple etiological factors, this disease is hard to be cured. Therefore, it is of great necessity for us to find novel targets or drugs for OA treatment.

Materials and methods

The chondrocytes were treated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP) to induce pyroptosis in OA. The cell proliferation was detected by Cell Counting Kit-8 assay (CCK-8 assay). Enzyme-linked immunosorbent assay (ELISA) was used for the detection of pyroptosis-related inflammatory factors. Then, the antagonists for gasdermin D (GSDMD) (disulfiram) and high mobility group box 1 (HMGB1) (glycyrrhizic acid) were used to treat the cell model to observe the effects of disulfiram and glycyrrhizic acid on the proliferation of chondrocytes in OA. The protein levels of pyroptosis-related inflammatory factors were measured by western blot, and the levels of aldehyde dehydrogenase (ALDH) and reactive oxygen species (ROS) were measured by corresponding commercial kits.

Results

After chondrocytes were induced by LPS and ATP, the cell proliferation was decreased and the expressions of pyroptosis-related inflammatory factors were increased. Disulfiram and glycyrrhizic acid treatment led to enhanced cell proliferation and increased expressions of pyroptosis-related inflammatory factors, while disulfiram showed better alleviative effects on the inflammation in chondrocytes in OA. However, co-treatment with disulfiram at a high concentration and glycyrrhizic acid did not result in higher proliferation of chondrocytes and alleviated inflammation, but led to oxidative stress.

Conclusion

In conclusion, co-treatment with disulfiram and glycyrrhizic acid at a standard concentration suppresses the inflammatory response of chondrocytes, which may provide guidance for the use of the drugs in the treatment of OA.

Apoptosis in infectious diseases as a mechanism of immune evasion and survival

In pluricellular organisms, apoptosis is indispensable for the development and homeostasis. During infection, apoptosis plays the main role in the elimination of infected cells. Infectious diseases control apoptosis, and this contributes to disease pathogenesis. Increased apoptosis may participate in two different ways. It can assist the dissemination of intracellular pathogens or induce immunosuppression to favor pathogen dissemination. In other conditions, apoptosis can benefit eradicate infectious agents from the host. Accordingly, bacteria, viruses, fungi, and parasites have developed strategies to inhibit host cell death by apoptosis to allow intracellular survival and persistence of the pathogen. The clarification of the intracellular signaling pathways, the receptors involved and the pathogen factors that interfere with apoptosis could disclose new therapeutic targets for blocking microbial actions on apoptotic pathways. In this review, we summarize the current knowledge on pathogen anti-apoptotic and apoptotic approaches and the mechanisms involving in disease.