Autophagy: Regulator of cell death

Tanreqing injection inhibits influenza virus replication by promoting the fusion of autophagosomes with lysosomes: An integrated pharmacological study

ETHNOPHARMACOLOGICAL RELEVANCE

Tanreqing injection (TRQ) is widely used, traditional Chinese medicine (TCM) injection used in China to treat respiratory infections. Modern pharmacological studies have confirmed that TRQ can protect against influenza viruses. However, the mechanism by which TRQ inhibits influenza viruses remains unclear.

AIM OF THE STUDY

To explore the therapeutic effects and possible mechanisms of TRQ inhibition by the influenza virus.

MATERIALS AND METHODS

Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) was used to determine the chemical composition of TRQ. Isobaric tags for relative and absolute quantification (iTRAQ) were used to define differential proteins related to TRQ inhibition of viruses. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for functional annotation. For experimental validation, we established an in vitro model of the influenza virus infection by infecting A549 cells with the virus. The detection of the signaling pathway was carried out through qPCR, western blotting,and immunofluorescence.

RESULTS

Fifty one components were identified using UPLC/Q-TOF MS. We confirmed the inhibitory effect of TRQ on influenza virus replication in vitro. Ninety nine differentially expressed proteins related to the inhibitory effect of TRQ were identified using iTRAQ. KEGG functional enrichment analysis showed that the TRQ may inhibit influenza virus replication by affecting autophagy. Through network analysis, 29 targets were selected as major targets, and three key targets, HSPA5, PARP1, and GAPDH, may be the TRQ targets affecting autophagy. In vitro experiments showed that TRQ inhibits influenza virus replication by interfering with the expression and localization of STX17 and VAMP8 proteins, thereby promoting the fusion of autophagosomes with lysosomes.

CONCLUSION

TRQ inhibits influenza virus replication by promoting the fusion of autophagosomes with lysosomes. We additionally established potential gene and protein targets which are affected by TRQ. Therefore, our findings provide new therapeutic targets and a foundation further studies on influenza treatment with TRQ.

Newsights of endoplasmic reticulum in hypoxia

The endoplasmic reticulum (ER) is important to cells because of its essential functions, including synthesizing three major nutrients and ion transport. When cellular homeostasis is disrupted, ER quality control (ERQC) system is activated effectively to remove misfolded and unfolded proteins through ER-phagy, ER-related degradation (ERAD), and molecular chaperones. When unfolded protein response (UPR) and ER stress are activated, the cell may be suffering a huge blow, and the most probable consequence is apoptosis. The membrane contact points between the ER and sub-organelles contribute to communication between the organelles. The decrease in oxygen concentration affects the morphology and structure of the ER, thereby affecting its function and further disrupting the stable state of cells, leading to the occurrence of disease. In this study, we describe the functions of ER-, ERQC-, and ER-related membrane contact points and their changes under hypoxia, which will help us further understand ER and treat ER-related diseases.

Cell death‑related molecules and targets in the progression of urolithiasis (Review)

Urolithiasis is a high‑incidence disease caused by calcium oxalate (mainly), uric acid, calcium phosphate, struvite, apatite, cystine and other stones. The development of kidney stones is closely related to renal tubule cell damage and crystal adhesion and aggregation. Cell death, comprising the core steps of cell damage, can be classified into various types (i.e., apoptosis, ferroptosis, necroptosis and pyroptosis). Different crystal types, concentrations, morphologies and sizes cause tubular cell damage via the regulation of different forms of cell death. Oxidative stress caused by high oxalate or crystal concentrations is considered to be a precursor to a variety of types of cell death. In addition, complex crosstalk exists among numerous signaling pathways and their key molecules in various types of cell death. Urolithiasis is considered a metabolic disorder, and tricarboxylic acid cycle‑related molecules, such as citrate and succinate, are closely related to cell death and the inhibition of stone development. However, a literature review of the associations between kidney stone development, metabolism and various types of cell death is currently lacking, at least to the best of our knowledge. Thus, the present review summarizes the major advances in the understanding of regulated cell death and urolithiasis progression.

Dysregulated dendritic cells in sepsis: functional impairment and regulated cell death

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Studies have indicated that immune dysfunction plays a central role in the pathogenesis of sepsis. Dendritic cells (DCs) play a crucial role in the emergence of immune dysfunction in sepsis. The major manifestations of DCs in the septic state are abnormal functions and depletion in numbers, which are linked to higher mortality and vulnerability to secondary infections in sepsis. Apoptosis is the most widely studied pathway of number reduction in DCs. In the past few years, there has been a surge in studies focusing on regulated cell death (RCD). This emerging field encompasses various forms of cell death, such as necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death (ADCD). Regulation of DC's RCD can serve as a possible therapeutic focus for the treatment of sepsis. Throughout time, numerous tactics have been devised and effectively implemented to improve abnormal immune response during sepsis progression, including modifying the functions of DCs and inhibiting DC cell death. In this review, we provide an overview of the functional impairment and RCD of DCs in septic states. Also, we highlight recent advances in targeting DCs to regulate host immune response following septic challenge.

Sperm freezing damage: the role of regulated cell death

Substantial progress in research on sperm cryopreservation has occurred since the twentieth century, especially focusing on improving sperm freezing procedures and optimizing semen extenders. However, the cellular biological mechanisms of sperm freezing damage are still unclear, which greatly restricts the promotion and development of sperm cryopreservation. An essential component of sperm freezing damage is the occurrence of cell death. Considering the existence of multiple types of cell death pathways, this review discusses connections between characteristics of regulated cell death (e.g., apoptosis and ferroptosis), and accidental cell death (e.g., intracellular ice crystals) with sperm freezing damage and explores possible future research directions in this field.

Recent advances in the effect of adipose tissue inflammation on insulin resistance

Obesity is one of the major risk factors for diabetes. Excessive accumulation of fat leads to inflammation of adipose tissue, which can increase the risk of developing diabetes. Obesity-related chronic inflammation can result in anomalies in glucose-lipid metabolism and insulin resistance, and it is a major cause of β-cell dysfunction in diabetes mellitus. Thus, a long-term tissue inflammatory response is crucial for metabolic diseases, particularly type 2 diabetes. Chronic inflammation associated with obesity increases oxidative stress, secretes inflammatory factors, modifies endocrine variables, and interferes with insulin signalling pathways, all of which contribute to insulin resistance and glucose tolerance. Insulin resistance and diabetes are ultimately caused by chronic inflammation in the stomach, pancreas, liver, muscle, and fat tissues. In this article, we systematically summarize the latest research progress on the mechanisms of adipose tissue inflammation and insulin resistance, as well as the mechanisms of cross-talk between adipose tissue inflammation and insulin resistance, with a view to providing some meaningful therapeutic strategies for the treatment of insulin resistance by controlling adipose tissue inflammation.

Boarding pyroptosis onto nanotechnology for cancer therapy

Pyroptosis, a non-apoptotic programmed cellular inflammatory death mechanism characterized by gasdermin (GSDM) family proteins, has gathered significant attention in the cancer treatment. However, the alarming clinical trial data indicates that pyroptosis-mediated cancer therapeutic efficiency is still unsatisfactory. It is essential to integrate the burgeoning biomedical findings and innovations with potent technology to hasten the development of pyroptosis-based antitumor drugs. Considering the rapid development of pyroptosis-driven cancer nanotherapeutics, here we aim to summarize the recent advances in this field at the intersection of pyroptosis and nanotechnology. First, the foundation of pyroptosis-based nanomedicines (NMs) is outlined to illustrate the reliability and effectiveness for the treatment of tumor. Next, the emerging nanotherapeutics designed to induce pyroptosis are overviewed. Moreover, the cross-talk between pyroptosis and other cell death modalities are discussed, aiming to explore the mechanistic level relationships to provide guidance strategies for the combination of different types of antitumor drugs. Last but not least, the opportunities and challenges of employing pyroptosis-based NMs in potential clinical cancer therapy are highlighted.

Glutathione Depletion and Stalwart Anticancer Activity of Metallotherapeutics Inducing Programmed Cell Death: Opening a New Window for Cancer Therapy

The cellular defense system against exogenous substances makes therapeutics inefficient as intracellular glutathione (GSH) exhibits an astounding antioxidant activity in scavenging reactive oxygen species (ROS) or reactive nitrogen species (RNS) or other free radicals produced by the therapeutics. In the cancer cell microenvironment, the intracellular GSH level becomes exceptionally high to fight against oxidative stress created by the production of ROS/RNS or any free radicals, which are the byproducts of intracellular redox reactions or cellular respiration processes. Thus, in order to maintain redox homeostasis for survival of cancer cells and their rapid proliferation, the GSH level starts to escalate. In this circumstance, the administration of anticancer therapeutics is in vain, as the elevated GSH level reduces their potential by reduction or by scavenging the ROS/RNS they produce. Therefore, in order to augment the therapeutic potential of anticancer agents against elevated GSH condition, the GSH level must be depleted by hook or by crook. Hence, this Review aims to compile precisely the role of GSH in cancer cells, the importance of its depletion for cancer therapy and examples of anticancer activity of a few selected metal complexes which are able to trigger cancer cell death by depleting the GSH level.

The liquid-liquid phase separation in programmed cell death

In recent years, the physical phenomenon of liquid-liquid phase separation has been widely introduced into biological research. Membrane-free organelles have been found to exist in cells that were driven by liquid-liquid phase separation. Intermolecular multivalent interactions can drive liquid-liquid phase separation to form condensates that are independent of other substances in the environment and thus can play an effective role in regulating multiple biological processes in the cell. The way of cell death has also long been a focus in multiple research. In the face of various stresses, cell death-related mechanisms are crucial for maintaining cellular homeostasis and regulating cell fate. With the in-depth study of cell death pathways, it has been found that the process of cell death was also accompanied by the regulation of liquid-liquid phase separation and played a key role. Therefore, this review summarized the roles of liquid-liquid phase separation in various cell death pathways, and explored the regulation of cell fate by liquid-liquid phase separation, with the expectation that the exploration of the mechanism of liquid-liquid phase separation would provide new insights into the treatment of diseases caused by regulated cell death.

Regulation mechanism of EBV-encoded EBER1 and LMP2A on YAP1 and the impact of YAP1 on the EBV infection status in EBV-associated gastric carcinoma

This study aims to explore the role and regulatory mechanism of Yes-associated protein 1 (YAP1) in the development of Epstein-Barr virus-associated gastric cancer (EBVaGC). Here we showed that EBV can upregulate the expression and activity of YAP1 protein through its encoded latent products EBV-encoded small RNA 1 (EBER1) and latent membrane protein 2A (LMP2A), enhancing the malignant characteristics of EBVaGC cells. In addition, we also showed that overexpression of YAP1 induced the expression of EBV encoding latent and lytic phase genes and proteins in the epithelial cell line AGS-EBV infected with EBV, and increased the copy number of the EBV genome, while loss of YAP1 expression reduced the aforementioned indicators. Moreover, we found that YAP1 enhanced EBV lytic reactivation induced by two known activators, 12-O-tetradecanoylhorbol-13-acetate (TPA) and sodium butyrate (NaB). These results indicated a bidirectional regulatory mechanism between EBV and YAP1 proteins, providing new experimental evidence for further understanding the regulation of EBV infection patterns and carcinogenic mechanisms in gastric cancer.

Glucosamine and Silibinin Alter Cartilage Homeostasis through Glycosylation and Cellular Stresses in Human Chondrocyte Cells

Osteoarthritis is more prevalent than any other form of arthritis and is characterized by the progressive mechanical deterioration of joints. Glucosamine, an amino monosaccharide, has been used for over fifty years as a dietary supplement to alleviate osteoarthritis-related discomfort. Silibinin, extracted from milk thistle, modifies the degree of glycosylation of target proteins, making it an essential component in the treatment of various diseases. In this study, we aimed to investigate the functional roles of glucosamine and silibinin in cartilage homeostasis using the TC28a2 cell line. Western blots showed that glucosamine suppressed the N-glycosylation of the gp130, EGFR, and N-cadherin proteins. Furthermore, both glucosamine and silibinin differentially decreased and increased target proteins such as gp130, Snail, and KLF4 in TC28a2 cells. We observed that both compounds dose-dependently induced the proliferation of TC28a2 cells. Our MitoSOX and DCFH-DA dye data showed that 1 µM glucosamine suppressed mitochondrial reactive oxygen species (ROS) generation and induced cytosol ROS generation, whereas silibinin induced both mitochondrial and cytosol ROS generation in TC28a2 cells. Our JC-1 data showed that glucosamine increased red aggregates, resulting in an increase in the red/green fluorescence intensity ratio, while all the tested silibinin concentrations increased the green monomers, resulting in decreases in the red/green ratio. We observed increasing subG1 and S populations and decreasing G1 and G2/M populations with increasing amounts of glucosamine, while increasing amounts of silibinin led to increases in subG1, S, and G2/M populations and decreases in G1 populations in TC28a2 cells. MTT data showed that both glucosamine and silibinin induced cytotoxicity in TC28a2 cells in a dose-dependent manner. Regarding endoplasmic reticulum stress, both compounds induced the expression of CHOP and increased the level of p-eIF2α/eIF2α. With respect to O-GlcNAcylation status, glucosamine and silibinin both reduced the levels of O-GlcNAc transferase and hypoxia-inducible factor 1 alpha. Furthermore, we examined proteins and mRNAs related to these processes. In summary, our findings demonstrated that these compounds differentially modulated cellular proliferation, mitochondrial and cytosol ROS generation, the mitochondrial membrane potential, the cell cycle profile, and autophagy. Therefore, we conclude that glucosamine and silibinin not only mediate glycosylation modifications but also regulate cellular processes in human chondrocytes.

Selected Flavonols Targeting Cell Death Pathways in Cancer Therapy: The Latest Achievements in Research on Apoptosis, Autophagy, Necroptosis, Pyroptosis, Ferroptosis, and Cuproptosis

The complex and multi-stage processes of carcinogenesis are accompanied by a number of phenomena related to the potential involvement of various chemopreventive factors, which include, among others, compounds of natural origin such as flavonols. The use of flavonols is not only promising but also a recognized strategy for cancer treatment. The chemopreventive impact of flavonols on cancer arises from their ability to act as antioxidants, impede proliferation, promote cell death, inhibit angiogenesis, and regulate the immune system through involvement in diverse forms of cellular death. So far, the molecular mechanisms underlying the regulation of apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis occurring with the participation of flavonols have remained incompletely elucidated, and the results of the studies carried out so far are ambiguous. For this reason, one of the therapeutic goals is to initiate the death of altered cells through the use of quercetin, kaempferol, myricetin, isorhamnetin, galangin, fisetin, and morin. This article offers an extensive overview of recent research on these compounds, focusing particularly on their role in combating cancer and elucidating the molecular mechanisms governing apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis. Assessment of the mechanisms underlying the anticancer effects of compounds in therapy targeting various types of cell death pathways may prove useful in developing new therapeutic regimens and counteracting resistance to previously used treatments.

The multifaceted role of autophagy in skin autoimmune disorders: a guardian or culprit?

Autophagy is a cellular process that functions to maintain intracellular homeostasis via the degradation and recycling of defective organelles or damaged proteins. This dynamic mechanism participates in various biological processes, such as the regulation of cellular differentiation, proliferation, survival, and the modulation of inflammation and immune responses. Recent evidence has demonstrated the involvement of polymorphisms in autophagy-related genes in various skin autoimmune diseases. In addition, autophagy, along with autophagy-related proteins, also contributes to homeostasis maintenance and immune regulation in the skin, which is associated with skin autoimmune disorders. This review aims to provide an overview of the multifaceted role of autophagy in skin autoimmune diseases and shed light on the potential of autophagy-targeting therapeutic strategies in dermatology.

Cholestane-3β,5α,6β-triol Induces Multiple Cell Death in A549 Cells via ER Stress and Autophagy Activation

Cholestane-3β,5α,6β-triol (CT) and its analogues are abundant in natural sources and are reported to demonstrate cytotoxicity toward different kinds of tumor cells without a deep probe into their mechanism of action. CT is also one of the major metabolic oxysterols of cholesterol in mammals and is found to accumulate in various diseases. An extensive exploration of the biological roles of CT over the past few decades has established its identity as an apoptosis inducer. In this study, the effects of CT on A549 cell death were investigated through cell viability assays. RNA-sequencing analysis and western blot of CT-treated A549 cells revealed the role of CT in inducing endoplasmic reticulum (ER) stress response and enhancing autophagy flux, suggesting a putative mechanism of CT-induced cell-death activation involving reactive oxygen species (ROS)-mediated ER stress and autophagy. It is reported for the first time that the upregulation of autophagy induced by CT can serve as a cellular cytotoxicity response in accelerating CT-induced cell death in A549 cells. This research provides evidence for the effect of CT as an oxysterol in cell response to oxidative damage and allows for a deep understanding of cholesterol in its response in an oxidative stress environment that commonly occurs in the progression of various diseases.

Dysfunctional mitochondria, disrupted levels of reactive oxygen species, and autophagy in B cells from common variable immunodeficiency patients

Introduction

Common Variable Immunodeficiency (CVID) patients are characterized by hypogammaglobulinemia and poor response to vaccination due to deficient generation of memory and antibody-secreting B cells. B lymphocytes are essential for the development of humoral immune responses, and mitochondrial function, hreactive oxygen species (ROS) production and autophagy are crucial for determining B-cell fate. However, the role of those basic cell functions in the differentiation of human B cells remains poorly investigated.

Methods

We used flow cytometry to evaluate mitochondrial function, ROS production and autophagy processes in human naïve and memory B-cell subpopulations in unstimulated and stimulated PBMCs cultures. We aimed to determine whether any alterations in these processes could impact B-cell fate and contribute to the lack of B-cell differentiation observed in CVID patients.

Results

We described that naïve CD19+CD27- and memory CD19+CD27+ B cells subpopulations from healthy controls differ in terms of their dependence on these processes for their homeostasis, and demonstrated that different stimuli exert a preferential cell type dependent effect. The evaluation of mitochondrial function, ROS production and autophagy in naïve and memory B cells from CVID patients disclosed subpopulation specific alterations. Dysfunctional mitochondria and autophagy were more prominent in unstimulated CVID CD19+CD27- and CD19+CD27+ B cells than in their healthy counterparts. Although naïve CD19+CD27- B cells from CVID patients had higher basal ROS levels than controls, their ROS increase after stimulation was lower, suggesting a disruption in ROS homeostasis. On the other hand, memory CD19+CD27+ B cells from CVID patients had both lower ROS basal levels and a diminished ROS production after stimulation with anti-B cell receptor (BCR) and IL-21.

Conclusion

The failure in ROS cell signalling could impair CVID naïve B cell activation and differentiation to memory B cells. Decreased levels of ROS in CVID memory CD19+CD27+ B cells, which negatively correlate with their in vitro cell death and autophagy, could be detrimental and lead to their previously demonstrated premature death. The final consequence would be the failure to generate a functional B cell compartment in CVID patients.

Exploiting Nanotechnology for Drug Delivery: Advancing the Anti-Cancer Effects of Autophagy-Modulating Compounds in Traditional Chinese Medicine

Background

Cancer continues to be a prominent issue in the field of medicine, as demonstrated by recent studies emphasizing the significant role of autophagy in the development of cancer. Traditional Chinese Medicine (TCM) provides a variety of anti-tumor agents capable of regulating autophagy. However, the clinical application of autophagy-modulating compounds derived from TCM is impeded by their restricted water solubility and bioavailability. To overcome this challenge, the utilization of nanotechnology has been suggested as a potential solution. Nonetheless, the current body of literature on nanoparticles delivering TCM-derived autophagy-modulating anti-tumor compounds for cancer treatment is limited, lacking comprehensive summaries and detailed descriptions.

Methods

Up to November 2023, a comprehensive research study was conducted to gather relevant data using a variety of databases, including PubMed, ScienceDirect, Springer Link, Web of Science, and CNKI. The keywords utilized in this investigation included "autophagy", "nanoparticles", "traditional Chinese medicine" and "anticancer".

Results

This review provides a comprehensive analysis of the potential of nanotechnology in overcoming delivery challenges and enhancing the anti-cancer properties of autophagy-modulating compounds in TCM. The evaluation is based on a synthesis of different classes of autophagy-modulating compounds in TCM, their mechanisms of action in cancer treatment, and their potential benefits as reported in various scholarly sources. The findings indicate that nanotechnology shows potential in enhancing the availability of autophagy-modulating agents in TCM, thereby opening up a plethora of potential therapeutic avenues.

Conclusion

Nanotechnology has the potential to enhance the anti-tumor efficacy of autophagy-modulating compounds in traditional TCM, through regulation of autophagy.

Lysosomes in Cancer-At the Crossroad of Good and Evil

Although it has been known for decades that lysosomes are central for degradation and recycling in the cell, their pivotal role as nutrient sensing signaling hubs has recently become of central interest. Since lysosomes are highly dynamic and in constant change regarding content and intracellular position, fusion/fission events allow communication between organelles in the cell, as well as cell-to-cell communication via exocytosis of lysosomal content and release of extracellular vesicles. Lysosomes also mediate different forms of regulated cell death by permeabilization of the lysosomal membrane and release of their content to the cytosol. In cancer cells, lysosomal biogenesis and autophagy are increased to support the increased metabolism and allow growth even under nutrient- and oxygen-poor conditions. Tumor cells also induce exocytosis of lysosomal content to the extracellular space to promote invasion and metastasis. However, due to the enhanced lysosomal function, cancer cells are often more susceptible to lysosomal membrane permeabilization, providing an alternative strategy to induce cell death. This review summarizes the current knowledge of cancer-associated alterations in lysosomal structure and function and illustrates how lysosomal exocytosis and release of extracellular vesicles affect disease progression. We focus on functional differences depending on lysosomal localization and the regulation of intracellular transport, and lastly provide insight how new therapeutic strategies can exploit the power of the lysosome and improve cancer treatment.

Carbon Ion Irradiation Activates Anti-Cancer Immunity

Carbon ion beams have the unique property of higher linear energy transfer, which causes clustered damage of DNA, impacting the cell repair system. This sometimes triggers apoptosis and the release in the cytoplasm of damaged DNA, leading to type I interferon (IFN) secretion via the activation of the cyclic GMP-AMP synthase-stimulator of interferon genes pathway. Dendritic cells phagocytize dead cancer cells and damaged DNA derived from injured cancer cells, which together activate dendritic cells to present cancer-derived antigens to antigen-specific T cells in the lymph nodes. Thus, carbon ion radiation therapy (CIRT) activates anti-cancer immunity. However, cancer is protected by the tumor microenvironment (TME), which consists of pro-cancerous immune cells, such as regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages. The TME is too robust to be destroyed by the CIRT-mediated anti-cancer immunity. Various modalities targeting regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages have been developed. Preclinical studies have shown that CIRT-mediated anti-cancer immunity exerts its effects in the presence of these modalities. In this review article, we provide an overview of CIRT-mediated anti-cancer immunity, with a particular focus on recently identified means of targeting the TME.

Endoplasmic reticulum stress and the unfolded protein response: emerging regulators in progression of traumatic brain injury

Traumatic brain injury (TBI) is a common trauma with high mortality and disability rates worldwide. However, the current management of this disease is still unsatisfactory. Therefore, it is necessary to investigate the pathophysiological mechanisms of TBI in depth to improve the treatment options. In recent decades, abundant evidence has highlighted the significance of endoplasmic reticulum stress (ERS) in advancing central nervous system (CNS) disorders, including TBI. ERS following TBI leads to the accumulation of unfolded proteins, initiating the unfolded protein response (UPR). Protein kinase RNA-like ER kinase (PERK), inositol-requiring protein 1 (IRE1), and activating transcription factor 6 (ATF6) are the three major pathways of UPR initiation that determine whether a cell survives or dies. This review focuses on the dual effects of ERS on TBI and discusses the underlying mechanisms. It is suggested that ERS may crosstalk with a series of molecular cascade responses, such as mitochondrial dysfunction, oxidative stress, neuroinflammation, autophagy, and cell death, and is thus involved in the progression of secondary injury after TBI. Hence, ERS is a promising candidate for the management of TBI.

Molecular Insights into Aggrephagy: Their Cellular Functions in the Context of Neurodegenerative Diseases

Protein homeostasis or proteostasis is an equilibrium of biosynthetic production, folding and transport of proteins, and their timely and efficient degradation. Proteostasis is guaranteed by a network of protein quality control systems aimed at maintaining the proteome function and avoiding accumulation of potentially cytotoxic proteins. Terminal unfolded and dysfunctional proteins can be directly turned over by the ubiquitin-proteasome system (UPS) or first amassed into aggregates prior to degradation. Aggregates can also be disposed into lysosomes by a selective type of autophagy known as aggrephagy, which relies on a set of so-called selective autophagy receptors (SARs) and adaptor proteins. Failure in eliminating aggregates, also due to defects in aggrephagy, can have devastating effects as underscored by several neurodegenerative diseases or proteinopathies, which are characterized by the accumulation of aggregates mostly formed by a specific disease-associated, aggregate-prone protein depending on the clinical pathology. Despite its medical relevance, however, the process of aggrephagy is far from being understood. Here we review the findings that have helped in assigning a possible function to specific SARs and adaptor proteins in aggrephagy in the context of proteinopathies, and also highlight the interplay between aggrephagy and the pathogenesis of proteinopathies.

Inhibiting Liver Autophagy and Promoting Hepatocyte Apoptosis by Schistosoma Japonicum Infection

We established a mouse model of Schistosoma japonicum infection in order to study the effects of the infection on hepatocyte autophagy and apoptosis. We also stimulated HepG2 cells with soluble egg antigens (SEA) in vitro. At two, four, and six weeks post-infection, quantitative real-time PCR and Western blot (WB) were used to detect liver expression levels of autophagy and apoptosis-related proteins. HepG2 cells were treated with different concentrations of SEA. The changes in the levels of autophagy-related proteins and HepG2 cell apoptosis were detected. The Lc3b, Beclin1, Atg7, and Atg12 mRNA levels were significantly lower at four and six weeks after infection than those in the uninfected group. At four and six weeks following infection, the levels of Beclin1, LC3BII/I, Atg7, and p62 proteins were considerably lower than those in the uninfected group. The protein levels of pro-apoptotic Bax and cleaved caspase 3 and fibrosis-related proteins α-SMA and collagen 3 in the liver post-infection were significantly higher than those in uninfected mice. HepG2 cells stimulated with SEA showed decreased levels of Beclin1, p62, and Atg7 proteins and significantly increased apoptosis rates. The findings demonstrated that following infection with S. japonicum, mice's liver fibrosis worsened, hepatic autophagy was suppressed, and hepatocyte apoptosis was encouraged.

Deterministic and stochastic approaches to a minimal model for the transition from autophagy to apoptosis

Autophagy and apoptosis are crucial cellular mechanisms. The cytoprotective function of autophagy is mediated by the negative regulation of apoptosis, which in turn inhibits autophagy. Although research into the molecular connection between autophagy and apoptosis is booming, the intricate regulatory mechanisms of this process are still not completely understood. Therefore, the objective of this study was to develop a minimal model to explore the transition from autophagy to apoptosis. This biological system was analyzed by comprehensively integrating both the deterministic and the stochastic dynamics of the cells. The system exhibited bistability, and the statistical properties of cells undergoing autophagy and apoptosis were analyzed at two different stress levels with varying noise strengths. Moreover, we investigated how noise affected the double negative feedback loops between autophagy and apoptosis and further triggered transitions at two different stress levels and initial conditions. Finally, the effect of noise on transition was comprehensively studied under continuous stress variations and the two different initial conditions, showing that stronger noise results in more randomness during the switching process. Our work may provide novel insights for further experiments and modeling.

The role of competing endogenous RNA network in the development of hepatocellular carcinoma: potential therapeutic targets

The current situation of hepatocellular carcinoma (HCC) management is challenging due to its high incidence, mortality, recurrence and metastasis. Recent advances in gene genetic and expression regulation have unveiled the significant role of non-coding RNA (ncRNA) in various cancers. This led to the formulation of the competing endogenous RNA (ceRNA) hypothesis, which posits that both coding RNA and ncRNA, containing miRNA response elements (MRE), can share the same miRNA sequence. This results in a competitive network between ncRNAs, such as lncRNA and mRNA, allowing them to regulate each other. Extensive research has highlighted the crucial role of the ceRNA network in HCC development, impacting various cellular processes including proliferation, metastasis, cell death, angiogenesis, tumor microenvironment, organismal immunity, and chemotherapy resistance. Additionally, the ceRNA network, mediated by lncRNA or circRNA, offers potential in early diagnosis and prevention of HCC. Consequently, ceRNAs are emerging as therapeutic targets for HCC. The complexity of these gene networks aligns with the multi-target approach of traditional Chinese medicine (TCM), presenting a novel perspective for TCM in combating HCC. Research is beginning to show that TCM compounds and prescriptions can affect HCC progression through the ceRNA network, inhibiting proliferation and metastasis, and inducing apoptosis. Currently, the lncRNAs TUG1, NEAT1, and CCAT1, along with their associated ceRNA networks, are among the most promising ncRNAs for HCC research. However, this field is still in its infancy, necessitating advanced technology and extensive basic research to fully understand the ceRNA network mechanisms of TCM in HCC treatment.

ROS: Executioner of regulating cell death in spinal cord injury

The damage to the central nervous system and dysfunction of the body caused by spinal cord injury (SCI) are extremely severe. The pathological process of SCI is accompanied by inflammation and injury to nerve cells. Current evidence suggests that oxidative stress, resulting from an increase in the production of reactive oxygen species (ROS) and an imbalance in its clearance, plays a significant role in the secondary damage during SCI. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial regulatory molecule for cellular redox. This review summarizes recent advancements in the regulation of ROS-Nrf2 signaling and focuses on the interaction between ROS and the regulation of different modes of neuronal cell death after SCI, such as apoptosis, autophagy, pyroptosis, and ferroptosis. Furthermore, we highlight the pathways through which materials science, including exosomes, hydrogels, and nanomaterials, can alleviate SCI by modulating ROS production and clearance. This review provides valuable insights and directions for reducing neuronal cell death and alleviating SCI through the regulation of ROS and oxidative stress.

The potential influence of melatonin on mitochondrial quality control: a review

Mitochondria are critical for cellular energetic metabolism, intracellular signaling orchestration and programmed death regulation. Therefore, mitochondrial dysfunction is associated with various pathogeneses. The maintenance of mitochondrial homeostasis and functional recovery after injury are coordinated by mitochondrial biogenesis, dynamics and autophagy, which are collectively referred to as mitochondrial quality control. There is increasing evidence that mitochondria are important targets for melatonin to exert protective effects under pathological conditions. Melatonin, an evolutionarily conserved tryptophan metabolite, can be synthesized, transported and metabolized in mitochondria. In this review, we summarize the important role of melatonin in the damaged mitochondria elimination and mitochondrial energy supply recovery by regulating mitochondrial quality control, which may provide new strategies for clinical treatment of mitochondria-related diseases.