Adrenomedullin alleviates the pyroptosis of Leydig cells by promoting autophagy via the ROS-AMPK-mTOR axis

Rosemary officinalis extract mitigates potassium dichromate-induced testicular degeneration in male rats: Insights from the Nrf2 and its target genes signaling pathway

This study aimed to investigate the protective effects of Rosemary ethanol extract (ROEE) on testicular damage induced by potassium Dichromate (PDC) in male rats regarding the signaling pathway of Nrf2 and its target genes and proteins. A total of 28 male rats were divided into four groups: control, PDC only (15 mg/kg b.w. orally), PDC + low dose ROEE (220 mg/kg b.w.), and PDC + high dose ROEE (440 mg/kg b.w.). After 28 days of consecutive treatment, the rats were sacrificed for histological, immunohistochemistry, and biochemical analyses. The results revealed that the ROEE treatment up-regulated the Nrf2 and its target genes (NQO1, HO-1) mRNA expressions compared to the PDC group. correspondingly, the protein levels of GCLM, GSH, SOD, and catalase were significantly increased in the ROEE-treated animals compared to the PDC-treated animals. Furthermore, ROEE administration led to increased serum levels of testosterone (T4) and decreased levels of estrogen (E2) compared to the PDC group. Semen analysis and histopathology demonstrated that ROEE administration significantly improved spermatological impairment caused by PDC. The immunoexpression of cytoplasmic HSP-90 was reduced in the ROEE-treated groups, while the expression of androgen receptor (AR) was markedly improved. ROEE exhibited protective effects against PDC-induced testicular damage, likely due to its antioxidant properties. However, further investigation is required to elucidate the underlying mechanisms of action.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.

Placental growth factor alleviates hyperglycemia-induced trophoblast pyroptosis by regulating mitophagy

INTRODUCTION

Hyperglycemia is closely related to trophoblast dysfunction during pregnancy and results in suppressed invasion, migration, and pro-inflammatory cell death of trophoblasts. Hyperglycemia is a dependent risk factor for gestational hypertension accompanied by decreased placental growth factor (PLGF), which is important for maternal and fetal development. However, there is currently a lack of evidence to support whether PLGF can alleviate trophoblast cell dysfunction caused by high blood sugar. Here, we aim to clarify the effect of hyperglycemia on trophoblast dysfunction and determine how PLGF affects this process.

METHODS

The changes in placental tissue histomorphology from gestational diabetes mellitus (GDM) patients were compared with those of normal placentas. HTR8/SVneo cells were cultured in different amounts of glucose to examine cellular pyroptosis, migration, and invasion as well as PLGF levels. Furthermore, the levels of pyroptosis-related proteins (NLRP3, pro-caspase1, caspase1, IL-1β, and Gasdermin D [GSDMD]) as well as autophagy-related proteins (LC3-II, Beclin1, and p62) were examined by Western blotting. The GFP-mRFP-LC3-II system and transmission electron microscopy were used to detect mitophagy levels, and small interfering RNAs targeting BCL2 Interacting Protein 3 (siBNIP3) and PTEN-induced kinase 1 (siPINK1) were used to determine the role of mitophagy in pyroptotic death of HTR-8/SVneo cells.

RESULTS

Our results show that hyperglycemia upregulates NLRP3, pro-caspase1, caspase1, IL-1β at the protein level in GDM patients. High glucose (HG, 25 mM) inhibits viability, invasion, and migration of trophoblast cells while suppressing superoxide dismutase levels and promoting malondialdehyde production, thus leading to a senescence associated beta-gal-positive cell burst. PLGF levels in nucleus and the cytosol are also inhibited by HG, whereas PLGF treatment inhibited pyroptosis-related protein levels of NLRP3, pro-caspase1, caspase1, IL-1β, and GSDMD, Gasdermin D N-terminal domain (GSDMD-N). HG-induced mitochondrial dysfunction and BNIP3 and PINK1/Parkin expression. Knocking down BINP3 and PINK1 abolished the protective role of PLGF by preventing mitophagy.

CONCLUSION

PLGF inhibited hyperglycemia, while PLGF reversed hyperglycemic injury by promoting mitophagy via the BNIP3/PINK1/Parkin pathway. Altogether, these results suggest that PLGF may protect against trophoblast dysfunction in diabetes.

Sirtuin 1-mediated autophagy regulates testosterone synthesis in Leydig cells of piglets

Testosterone is secreted by Leydig cells (LCs), which play an important physiological role in preserving male secondary sex characteristics, protecting male reproductive function, and establishing the blood-testis barrier. Studies have shown that autophagy is particularly active in LCs; however, its involvement in testosterone synthesis in porcine LCs has not been fully explored. Therefore, this experiment aimed to investigate the influence of autophagy on testosterone secretion in porcine LCs and its potential regulatory mechanism. Our results demonstrated that both testicular autophagy and serum testosterone levels increased in piglets during postnatal development from 4 to 18 weeks. In addition, autophagy was found to degrade the Na+/H+ exchange regulatory factor 2 (NHERF2), leading to the up-regulation of scavenger receptor class B type 1 (SRB1). This process resulted in increased cholesterol intake and enhanced testosterone production. The observable level of sirtuin 1 (SIRT1) was directly proportional to the level of autophagy. In vitro investigations have shown that SIRT1 can affect the level of autophagy, cholesterol uptake as well as testosterone release. In conclusion, testosterone synthesis during pig development is regulated by SIRT1. SIRT1 mediates the degradation of NHERF2 through autophagy, thereby weakening its negative regulatory effect on the high-density lipoprotein receptor SRB1 in Leydig cells. This process increases cholesterol uptake and enhances testosterone synthesis.

A new insight into the mechanism of dichlorodiphenyltrichloroethane-induced hepatotoxicity based on GSDME-mediated pyroptosis

There have been persistent concerns about the safety risks associated with DDT residues in the environment. Studies have shown that exposure to DDT or its metabolites can cause various liver diseases. However, the mechanisms of liver toxicity haven't been well studied. In our current investigation, we observed that DDT triggers pyroptosis in human liver cells (HL-7702), representing a novel form of programmed cell death. Our results delineated DDT (0-100 μM) induced pyroptosis in HL-7702 cells, which was confirmed through morphological changes, lactate dehydrogenase (LDH) release, gasdermin E (GSDME) cleavage and Annexin-V/PI staining. Knockdown of GSDME reduced cell death and transferred the mode of cell death from pyroptosis to apoptosis. Notably, DDT exposure markedly increased reactive oxygen species (ROS) production, concurrent with c-Jun N-terminal kinase (JNK) phosphorylation. Intervention with a ROS inhibitor or JNK inhibitor SP600125 restored cell viability and hindered GSDME-mediated pyroptosis. Our results firstly demonstrate that DDT suppresses HL-7702 cells growth by inducing pyroptosis mainly through the ROS/JNK/GSDME pathway. These findings not only contribute to an in-depth understanding of DDT toxicity but also open avenues for gaining valuable insights into potential mitigation strategies and therapeutic interventions.

Lactic acid regulates lipid droplet aggregation through a microglia-neuron axis in neuroinflammation

Neuroinflammation, marked by the release of proinflammatory cytokines and resulting neuronal death, is a multifaceted process extending beyond traditional inflammatory pathways. Microglia, primary cells in the inflammatory response, rapidly activate during neuroinflammation and produce proinflammatory and cytotoxic factors that affect neuronal function. Recent evidence highlights the significant role of abnormal lipid droplet (LD) deposition in the pathogenesis of neuroinflammation. While microglia are known to influence LD aggregation during neuroinflammation, the regulatory mechanism within neurons is not well understood. Our study demonstrates that lipopolysaccharide-activated microglia induce the accumulation of LD in neurons, identifying microglial-derived lactic acid as a key mediator in this process. Excessive lipid accumulation threatens neuronal function, a phenomenon reversed by eliminating microglia. Our study demonstrates that lipopolysaccharide-activated microglia induce the accumulation of LD in neurons, identifying microglial-derived lactic acid as a key mediator in this process. Excessive lipid accumulation threatens neuronal function, a phenomenon reversed by eliminating microglia.

Irisin alleviates the pyroptosis of β cells in T2DM by inhibiting NLRP3 inflammasome through regulating miR-19b-3p/SOCS3/STAT3 axis mediated autophagy

The purpose of this study was to analyze the mechanism by which irisin affects β-cell pyroptosis in type 2 diabetes mellitus (T2DM). The in vivo T2DM model was established by raised with high-fat diet and intraperitoneally injection of streptozocin. Min6 cells were divided into four groups: negative control (NC), high glucose (HG), HG + irisin, and HG + irisin+3-MA. The cell viability was determined by CCK-8 assay. Dual-luciferase gene reporter assay was conducted to confirm the binding between miR-19b-3p and SOCS3. The expression level of FNDC5 and GSDMD was visualized using the immunofluorescence assay. The protein level of FNDC5, Beclin1, LC3II/I, NLRP3, cleaved-caspase-1, GSDMD-N, STAT3, p-STAT3, and SOCS3 was determined by Western blotting. The secretion of irisin, lactate dehydrogenase (LDH), and insulin was checked by ELISA. In vivo results showed that pathological changes in islet tissues with declined number of β cells, elevated FBG value, decreased FIN and HOMA-β value, elevated autophagy-associated proteins expressions, and activated NLRP3 signaling in T2DM mice, which were dramatically reversed by FNDC5 overexpression. Furthermore, the declined level of miR-19b-3p and p-STAT3, as well as the upregulation of SOCS3, was greatly rescued by FNDC5 overexpression. The in vitro data confirmed the binding site between SOCS3 and miR-19b-3p. SOCS3 was downregulated and p-STAT3 was upregulated in miR-19b-3p mimic-treated Min6 cells. In HG-stimulated Min6 cells, the elevated cell viability, increased production of insulin, decreased release of LDH, and inactivated NLRP3 signaling induced by irisin were abolished by miR-19b-3p inhibitor and STAT3 inhibitor. The increased level of autophagy-related proteins and activated SOCS3/STAT3 axis induced by irisin in HG-stimulated Min6 cells were abolished by miR-19b-3p inhibitor. The inhibitory effect of irisin against NLRP3 signaling in HG-stimulated Min6 cells was abrogated by 3-MA. In conclusion, irisin alleviated the pyroptosis of β cells in T2DM by inhibiting NLRP3 signaling through miR-19b-3p/SOCS3/STAT3 axis mediated autophagy.

The phenotypic changes of Schwann cells promote the functional repair of nerve injury

Functional recovery after nerve injury is a significant challenge due to the complex nature of nerve injury repair and the non-regeneration of neurons. Schwann cells (SCs), play a crucial role in the nerve injury repair process because of their high plasticity, secretion, and migration abilities. Upon nerve injury, SCs undergo a phenotypic change and redifferentiate into a repair phenotype, which helps in healing by recruiting phagocytes, removing myelin fragments, promoting axon regeneration, and facilitating myelin formation. However, the repair phenotype can be unstable, limiting the effectiveness of the repair. Recent research has found that transplantation of SCs can be an effective treatment option, therefore, it is essential to comprehend the phenotypic changes of SCs and clarify the related mechanisms to develop the transplantation therapy further.

Thymoquinone effects on autophagy, apoptosis, and oxidative stress in cisplatin-induced testicular damage in mice

PURPOSE

In this study, the effect of thymoquinone (TQ) on CP-induced spermatogenesis defects in mice has been investigated.

METHODS

Sperm parameters, serum testosterone concentration, histology, Bax/Bcl-2 ratio, and expression of autophagy-related biomarkers have been assessed. Total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) in testicular tissue were examined for the evaluation of oxidative stress levels.

RESULTS

CP has induced histological changes and significantly increased the Bax/Bcl-2 ratio, decreased testosterone concentration, testicular weight, and sperm quality. CP induced oxidative stress by elevating OSI in the testicular tissue (p < 0.05). Expression of the autophagy-inducer genes (ATG7, ATG5, and Beclin-1) and ratio of LC3B/LC3A proteins were significantly decreased, while mTOR expression was increased in the CP group. TQ pretreatment dose-dependently decreased the Bax/Bcl-2 ratio and mTOR gene expression while increasing the expression of ATG5 and ATG7 genes, LC3B/LC3A ratio, and Beclin-1 proteins. TQ could also dose-dependently reverse the histology, testosterone level, and sperm quality of the CP-intoxicated mice.

CONCLUSIONS

These findings show that TQ pretreatment can enhance sperm production by inducing autophagy and reducing apoptosis and oxidative stress in the CP-intoxicated mouse testicles.

Lycopene inhibits pyroptosis of endothelial progenitor cells induced by ox-LDL through the AMPK/mTOR/NLRP3 pathway

The malfunction of endothelial progenitor cells (EPCs) due to ox-LDL is a risk contributor for arteriosclerotic disease. Meanwhile, lycopene possesses anti-inflammatory and antioxidative qualities. This investigation aimed to determine if lycopene can protect EPCs from ox-LDL-induced damage and to elucidate the underlying mechanism. The effects of lycopene on the survival, migration, and tube-forming capacity of EPCs were determined via in vitro assays. Expression of proteins related to pyroptosis and cellular proteins related to AMPK/mTOR/NLRP3 signaling was determined by western blot/flow cytometry. Our results demonstrated that lycopene treatment significantly enhanced proliferation, tube formation, and migration of EPCs stimulated by ox-LDL. Additionally, lycopene was found to suppress pyroptosis in ox-LDL-induced EPCs through the activation of AMPK, which led to the inhibition of mTOR phosphorylation and subsequent downregulation of the downstream NLRP3 inflammasome. In summary, our study suggests that lycopene mitigates ox-LDL-induced dysfunction in EPCs and inhibits pyroptosis via AMPK/mTOR/NLRP3 signaling. Our study suggests that lycopene may act as promising therapies for preventing atherosclerosis.

Celastrol enhances the viability of random-pattern skin flaps by regulating autophagy through the AMPK-mTOR-TFEB axis

In reconstructive and plastic surgery, random-pattern skin flaps (RPSF) are often used to correct defects. However, their clinical usefulness is limited due to their susceptibility to necrosis, especially on the distal side of the RPSF. This study validates the protective effect of celastrol (CEL) on flap viability and explores in terms of underlying mechanisms of action. The viability of different groups of RPSF was evaluated by survival zone analysis, laser doppler blood flow, and histological analysis. The effects of CEL on flap angiogenesis, apoptosis, oxidative stress, and autophagy were evaluated by Western blot, immunohistochemistry, and immunofluorescence assays. Finally, its mechanistic aspects were explored by autophagy inhibitor and Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor. On the seventh day after surgery, the survival area size, blood supply, and microvessel count of RPSF were augmented following the administration of CEL. Additionally, CEL stimulated angiogenesis, suppressed apoptosis, and lowered oxidative stress levels immediately after elevated autophagy in ischemic regions; These effects can be reversed using the autophagy inhibitor chloroquine (CQ). Specifically, CQ has been observed to counteract the protective impact of CEL on the RPSF. Moreover, it has also been discovered that CEL triggers the AMPK-mTOR-TFEB axis activation in the area affected by ischemia. In CEL-treated skin flaps, AMPK inhibitors were demonstrated to suppress the AMPK-mTOR-TFEB axis and reduce autophagy levels. This investigation suggests that CEL benefits the survival of RPSF by augmenting angiogenesis and impeding oxidative stress and apoptosis. The results are credited to increased autophagy, made possible by the AMPK-mTOR-TFEB axis activation.

Subacute ruminal acidosis induces pyroptosis via the mitophagy-mediated NLRP3 inflammasome activation in the livers of dairy cows fed a high-grain diet

High-grain (HG) feeding can trigger subacute ruminal acidosis (SARA) and subsequent liver tissue injury. This study investigated pyroptosis and NLRP3 inflammasome activation in SARA-induced liver injury, and the role of mitophagy during this process. Twelve mid-lactating Holstein cows equipped with rumen fistulas were randomly divided into 2 groups: a low-grain (LG) diet group (grain:forage = 4:6) and a HG diet group (grain:forage = 6:4). Each group had 6 cows. The experiment lasted for 3 wk. The ruminal fluid was collected through the rumen fistula on experimental d 20 and 21, and the pH immediately measured. At the end of the experiment, all animals were slaughtered, and peripheral blood and liver tissue were collected. The ruminal pH was lower in the HG group than that in the LG group at all time points. In addition, the ruminal pH in the HG group was lower than 5.6 at 3 consecutive time points after feeding (4, 6, and 8 h on d 20; 2, 4, and 6 h on d 21), indicating that HG feeding induced SARA. The content of lipopolysaccharide, IL-1β, and apoptosis-related cysteine protease 1 (caspase-1) and the activity of alanine aminotransferase and aspartate aminotransferase in the blood plasma of the HG group were all significantly increased. Hepatic caspase-1 activity was increased in the livers of the HG group. The increased expression levels of pyroptosis- and NLRP3 inflammasome-related genes IL1B, IL18, gasdermin D (GSDMD), apoptosis-associated speck-like protein containing a card (ASC), NLR family pyrin domain-containing 3 (NLRP3), and caspase-1 (CASP1) in liver tissue of the HG group were detected. Furthermore, western blot analysis showed that HG feeding led to increased expression of pyroptosis- and NLRP3 inflammasome-related proteins GSDMD N-terminal (GSDMD-NT), IL-1β, IL-18, cleaved-caspase-1, ASC, NLRP3, and cleaved-caspase-11 and upregulated expression of mitophagy-related proteins microtubule-associated protein 1 light chain 3 II (MAP1LC3-II), beclin 1 (BECN1), Parkin, and PTEN-induced kinase 1 (PINK1) in liver tissue. Collectively, our results revealed that SARA caused increased mitophagy and activated the NLRP3 inflammasome, causing pyroptosis and subsequent liver injury in dairy cows fed a HG diet.

Prenatal diethylhexylphthalate exposure disturbs adult Leydig cell function via epigenetic downregulation of METTL4 expression in male rats

Prenatal exposure to diethylhexyl phthalate (DEHP) has been linked with a decline in testosterone levels in adult male rats, but the underlying mechanism remains unclear. We investigated the potential epigenetic regulation, particularly focusing on N6-methyladenosine (m6A) modification, as a possible mechanism. Dams were gavaged with DEHP (0, 10, 100, and 750 mg/kg/day) from gestational day 14 to day 21. The male offspring were examined at the age of 56 days. Prenatal DEHP administration at 750 mg/kg/day caused a decline in testosterone concentrations, an elevation in follicle-stimulating hormone, a downregulated expression of CYP11A1 HSD3B2, without affecting Leydig cell numbers. Interestingly, Methyltransferase Like 4 (METTL4), an m6A methyltransferase, was downregulated, while there were no changes in METTL3 and METTL14. Moreover, CYP11A1 showed m6A reduction in response to prenatal DEHP exposure. Additionally, METTL4 expression increased postnatally, peaking in adulthood. Knockdown of METTL4 resulted in the downregulation of CYP11A1 and HSD3B2 and an increase in SCARB1 expression. Furthermore, the increase in autophagy protection in adult Leydig cells induced by prenatal DEHP exposure was not affected by 3-methyladenosine (3MA) treatment, indicating a potential protective role of autophagy in response to DEHP exposure. In conclusion, prenatal DEHP exposure reduces testosterone by downregulating CYP11A1 and HSD3B2 via m6A epigenetic regulation and induction of autophagy protection in adult Leydig cells as a response to DEHP exposure.

Activation of SIRT1/Nrf2/HO-1 and Beclin-1/AMPK/mTOR autophagy pathways by eprosartan ameliorates testicular dysfunction induced by testicular torsion in rats

Testicular torsion carries the ominous prospect of inducing acute scrotal distress and the perilous consequence of testicular atrophy, necessitating immediate surgical intervention to reinstate vital testicular perfusion, notwithstanding the paradoxical detrimental impact of reperfusion. Although no drugs have secured approval for this urgent circumstance, antioxidants emerge as promising candidates. This study aspires to illustrate the influence of eprosartan, an AT1R antagonist, on testicular torsion in rats. Wistar albino rats were meticulously separated into five groups, (n = 6): sham group, eprosartan group, testicular torsion-detorsion (T/D) group, and two groups of T/D treated with two oral doses of eprosartan (30 or 60 mg/kg). Serum testosterone, sperm analysis and histopathological examination were done to evaluate spermatogenesis. Oxidative stress markers were assessed. Bax, BCL-2, SIRT1, Nrf2, HO-1 besides cleaved caspase-3 testicular contents were estimated using ELISA or qRT-PCR. As autophagy markers, SQSTM-1/p62, Beclin-1, mTOR and AMPK were investigated. Our findings highlight that eprosartan effectively improved serum testosterone levels, testicular weight, and sperm count/motility/viability, while mitigating histological irregularities and sperm abnormalities induced by T/D. This recovery in testicular function was underpinned by the activation of the cytoprotective SIRT1/Nrf2/HO-1 axis, which curtailed testicular oxidative stress, indicated by lowering the MDA content and increasing GSH content. In terms of apoptosis, eprosartan effectively countered apoptotic processes by decreasing cleaved caspase-3 content, suppressing Bax and stimulating Bcl-2 gene expression. Simultaneously, it reactivated impaired autophagy by increasing Beclin-1 expression, decreasing the expression of SQSTM-1/p62 and modulate the phosphorylation of AMPK and mTOR proteins. Eprosartan hold promise for managing testicular dysfunction arising from testicular torsion exerting antioxidant, pro-autophagic and anti-apoptotic effect via the activation of SIRT1/Nrf2/HO-1 as well as Beclin-1/AMPK/mTOR pathways.

Fluoride induces pyroptosis via IL-17A-mediated caspase-1/11-dependent pathways and Bifidobacterium intervention in testis

Fluoride, a ubiquitous environmental pollutant, poses a significant public health threat. Our previous study revealed a correlation between fluoride-induced testicular pyroptosis and male reproductive dysfunction. However, the underlying mechanism remains unclear. Wild-type and interleukin 17A knockout mice were exposed to sodium fluoride (100 mg/L) in deionized drinking water for 18 weeks. Bifidobacterium intervention (1 × 109 CFU/mL, 0.2 mL/day, administered via gavage) commenced in the 10th week. Sperm quality, testicular morphology, key pyroptosis markers, spermatogenesis key genes, IL-17A signaling pathway, and pyroptosis pathway related genes were determined. The results showed that fluoride reduced sperm quality, damaged testicular morphology, affected spermatogenesis, elevated IL-17A levels, and induced testicular pyroptosis. Bifidobacterium intervention alleviated adverse reproductive outcomes. Fluoride-activated testicular pyroptosis through both typical and atypical pathways, with IL-17A involvement. Bifidobacterium supplementation attenuated pyroptosis by downregulating IL-17A, inhibiting NLRP3 and PYRIN-mediated caspase-1 and caspase-11 dependent pathways in testis, thereby alleviating fluoride-induced male reproductive damage. In summary, this study uncovers the mechanism underlying fluorine-induced testicular pyroptosis and illustrates the novel protecting feature of Bifidobacterium against fluoride-induced harm to male reproduction, along with its potential regulatory mechanism. These results provide fresh perspectives on treating male reproductive dysfunction resulting from fluoride or other environmental toxins.

Protective Effect and Mechanism of Autophagy in Endothelial Cell Injury Induced by Hyperoxia

OBJECTIVE

Bronchopulmonary dysplasia is a chronic lung disease in premature infants with alveolar simplification and pulmonary vascular development disorder as the main pathological feature and hyperoxia as the main etiology. Autophagy is a highly conserved cytological behavior of self-degrading cellular components and is accompanied by oxidative stress. Studies have reported that autophagy is regulated by FOXO1 posttranslational modification. However, whether autophagy can be involved in the regulation of endothelial cell injury induced by hyperoxia and its mechanism are still unclear.

STUDY DESIGN

We have activated and inhibited autophagy in human umbilical vein endothelial cells under hyperoxia and verified the role of autophagy in endothelial cell-related functions from both positive and negative aspects.

RESULTS

Our research showed that the expression level of autophagy-related proteins decreased, accompanied by decreased cell migration ability and tube formation ability and increased cell reactive oxygen species level and cell permeability under hyperoxia conditions. Using an autophagy agonist alleviated hyperoxia-induced changes and played a protective role. However, inhibition of autophagy aggravated the cell damage induced by hyperoxia. Moreover, the decrease in autophagy proteins was accompanied by the upregulation of FOXO1 phosphorylation and acetylation.

CONCLUSION

We concluded that autophagy was a protective mechanism against endothelial cell injury caused by hyperoxia. Autophagy might participate in this process by coregulating posttranslational modifications of FOXO1.

KEY POINTS

· Hyperoxia induces vascular endothelial cell injury.. · Autophagy may has a protective role under hyperoxia conditions.. · FOXO1 posttranslational modification may be involved in the regulation of autophagy..

Remodeling of the Intra-Conduit Inflammatory Microenvironment to Improve Peripheral Nerve Regeneration with a Neuromechanical Matching Protein-Based Conduit

Peripheral nerve injury (PNI) remains a challenging area in regenerative medicine. Nerve guide conduit (NGC) transplantation is a common treatment for PNI, but the prognosis of NGC treatment is unsatisfactory due to 1) neuromechanical unmatching and 2) the intra-conduit inflammatory microenvironment (IME) resulting from Schwann cell pyroptosis and inflammatory-polarized macrophages. A neuromechanically matched NGC composed of regenerated silk fibroin (RSF) loaded with poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (P:P) and dimethyl fumarate (DMF) are designed, which exhibits a matched elastic modulus (25.1 ± 3.5 MPa) for the peripheral nerve and the highest 80% elongation at break, better than most protein-based conduits. Moreover, the NGC can gradually regulate the intra-conduit IME by releasing DMF and monitoring sciatic nerve movements via piezoresistive sensing. The combination of NGC and electrical stimulation modulates the IME to support PNI regeneration by synergistically inhibiting Schwann cell pyroptosis and reducing inflammatory factor release, shifting macrophage polarization from the inflammatory M1 phenotype to the tissue regenerative M2 phenotype and resulting in functional recovery of neurons. In a rat sciatic nerve crush model, NGC promoted remyelination and functional and structural regeneration. Generally, the DMF/RSF/P:P conduit provides a new potential therapeutic approach to promote nerve repair in future clinical treatments.

FoxG1 as a Potential Therapeutic Target for Alzheimer's Disease: Modulating NLRP3 Inflammasome via AMPK/mTOR Autophagy Pathway

An increasing body of research suggests that promoting microglial autophagy hinders the neuroinflammation initiated though the NLRP3 inflammasome activation in Alzheimer's disease (AD). The function of FoxG1, a crucial transcription factor involved in cell survival by regulating mitochondrial function, remains unknown during the AD process and neuroinflammation occurs. In the present study, we firstly found that Aβ peptides induced AD-like neuroinflammation upregulation and downregulated the level of autophagy. Following low-dose Aβ25-35 stimulation, FoxG1 expression and autophagy exhibited a gradual increase. Nevertheless, with high-concentration Aβ25-35 treatment, progressive decrease in FoxG1 expression and autophagy levels as the concentration of Aβ25-35 escalated. In addition, FoxG1 has a positive effect on cell viability and autophagy in the nervous system. In parallel with the Aβ25-35 stimulation, we employed siRNA to decrease the expression of FoxG1 in N2A cells. A substantial reduction in autophagy level (Beclin1, LC3II, SQSTM1/P62) and a notable growth in inflammatory response (NLRP3, TNF-α, and IL-6) were observed. In addition, we found FoxG1 overexpression owned the effect on the activation of AMPK/mTOR autophagy pathway and siRNA-FoxG1 successfully abolished this effect. Lastly, FoxG1 suppressed the NLRP3 inflammasome and enhanced the cognitive function in AD-like mouse model induced by Aβ25-35. Confirmed by cellular and animal experiments, FoxG1 suppressed NLRP3-mediated neuroinflammation, which was strongly linked to autophagy regulated by AMPK/mTOR. Taken together, FoxG1 may be a critical node in the pathologic progression of AD and has the potential to serve as therapeutic target.

Inhibition of inosine metabolism of the gut microbiota decreases testosterone secretion in the testis

Growing evidence indicates that gut microbiota is involved in the regulation of the host's sex hormone levels, such as through interfering with the sex hormone metabolism in the intestine. However, if gut microbiota or its metabolites directly influence the sex hormone biosynthesis in the gonad remains largely unknown. Our previous study showed that colistin, as a narrow-spectrum antibiotic, can significantly downregulate the serum testosterone levels and thus enhance the antitumor efficiency of anti-PD-L1 in male mice; however, the underlying mechanism for the regulation of the host's testosterone levels remains uninvestigated. In the present study, we analyzed the impact of colistin on the immune microenvironment of the testis as well as the composition and metabolism of gut microbiota in male mice. Our results showed that colistin has an impact on the immune microenvironment of the testis and can downregulate serum testosterone levels in male mice through inhibition of Akkermansia, leading to destroyed inosine metabolism. Supplement with inosine can restore testosterone secretion probably by prompting the recovery of the intestinal mucus barrier and the serum lipopolysaccharides levels. All these findings reveal a new pathway for the regulation of the host's sex hormone levels by gut microbiota.IMPORTANCEThis study demonstrates that exposure to even narrow-spectrum antibiotics may affect the host's testosterone levels by altering the gut microbiota and its metabolites. Our findings provide evidence that some specific gut bacteria have an impact on the sex hormone biosynthesis in the testis.

Emodin activates autophagy to suppress oxidative stress and pyroptosis via mTOR-ULK1 signaling pathway and promotes multi-territory perforator flap survival

BACKGROUND

Multi-territory perforator flap reconstruction has been proven effective in treating large skin and soft tissue defects in clinical settings. However, in view of that the multi-territory perforator flap is prone to partial postoperative necrosis, increasing its survival is the key to the success of reconstruction. In this study, we aimed to clarify the effect of emodin on multi-territory perforator flap survival.

METHODS

Flap survival was assessed by viability area analysis, infrared laser imaging detector, HE staining, immunohistochemistry, and angiography. Western blotting, immunofluorescence assays, and real-time fluorescent quantitative PCR were performed to detect the indicators of oxidative stress, pyroptosis and autophagy.

RESULTS

After emodin treatment, the multi-territory perforator flap showed a significantly increased survival rate, which was shown to be closely related to the inhibition of oxidative stress and pyroptosis and enhanced autophagy. Meanwhile, the use of autophagy inhibitor 3 MA was found to reverse the inhibitory effects of emodin on oxidative stress and pyroptosis and weaken the improving effect of emodin on flap survival, suggesting that autophagy plays a critical role in emodin-treated flaps. Interestingly, our mechanistic investigations revealed that the positive effect of emodin on multi-territory perforator flap was attributed to the mTOR-ULK1 signaling pathway activation.

CONCLUSIONS

Emodin can inhibit oxidative stress and pyroptosis by activating autophagy via the mTOR-ULK1 pathway, thereby improving the multi-territory perforator flap survival.

Integration of network pharmacology and experimental verifications reveals the Bian-Se-Tong mixture can alleviate constipation in STC rats by reducing apoptosis of Cajal cells via activating PI3K-Akt signaling pathway

Bian-Se-Tong mixture (BSTM) is an optimized formulation based on the classical prescription "Zhizhu pill", which is widely used in the clinical treatment of slow-transit constipation (STC). The potential molecular mechanism of BSTM therapy for STC was investigated by network pharmacology prediction combined with animal experiments. The active components of BSTM were screened via the TCMSP platform. The GeneCards, OMIM and DrugBank databases were used to search for STC targets. With the help of the Biogenet tool, a protein interaction network between drugs and disease targets was constructed, and the intersection network of the two was extracted to obtain the key targets of BSTM in the treatment of STC. GO and KEGG enrichment analyses of key targets were carried out with Metascape. Loperamide hydrochloride was used to establish an STC rat model, and the key targets and related pathways were preliminarily verified. The important signaling pathways included the PI3K-Akt, MAPK, IL-17, cAMP, and cell cycle signaling pathways. The experimental results showed that BSTM treatment increased the body weight of STC rats and increased the fecal particle number, fecal water content and intestinal carbon ink promotion rate within 24 h. Further pathological changes in the colon of the rats were also observed. In-depth mechanistic studies have shown that BSTM can significantly reduce the apoptosis of intestinal Cajal cells, downregulate the expression of Bax and c-Caspase 3, upregulate the expression of Bcl-2 and c-kit, and promote the phosphorylation of AKT. The results showed that BSTM can significantly relieve constipation in STC rats via a mechanism related to activating the PI3K-Akt signaling pathway and improving Cajal cell apoptosis.

The roles of autophagy, ferroptosis and pyroptosis in the anti-ovarian cancer mechanism of harmine and their crosstalk

This study aimed to investigate the role of autophagy, ferroptosis, and pyroptosis in the antitumour mechanism of harmine (Har) and its crosstalk in ovarian cancer. By transmission electron microscopy, we found that compared with those in the control group, the cytoplasm of human ovarian cancer cells (SKOV3) treated with Har showed increased numbers of autophagic vesicles, decreased intracellular mitochondrial volume, increased bilayer membrane density, and decreased cristae. Western blot, immunofluorescence, and monodasylcadaverine (MDC) staining all suggested that Har promoted autophagy in SKOV3 cells. LY294002 and siFOXO3 rescued the inhibition of the PI3K/AKT/mTOR/FOXO3 signalling pathway and the promotion of autophagy by Har. Additionally, the levels of ferroptosis- and pyroptosis-related proteins and the levels of Fe2+ , glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD) suggested that Har promoted ferroptosis and pyroptosis in SKOV3 cells. Interestingly, pretreatment with chloroquine (CQ), erastin, rapamycin (Rap), or ferrostatin-1 (Fer-1) increased or reversed the ferroptosis and pyroptosis promoted by Har, respectively. In vivo, the volume of tumours in the Har group was decreased, and immunohistochemistry revealed decreased levels of Ki-67 and GPX4 and increased levels of ATG5 and NARL3. In conclusion, Har exerts its anti-ovarian cancer effect not only by promoting autophagy by regulating the PI3K/AKT/mTOR/FOXO3 signalling pathway but also by promoting ferroptosis and pyroptosis. Additionally, there is complex crosstalk between autophagy, ferroptosis, and pyroptosis in ovarian cancer.

The role of hydrogen sulfide regulation of pyroptosis in different pathological processes

Pyroptosis is one kind of programmed cell death in which the cell membrane ruptures and subsequently releases cell contents and pro-inflammatory cytokines including IL-1β and IL-18. Pyroptosis is caused by many types of pathological stimuli, such as hyperglycemia (HG), oxidative stress, and inflammation, and is mediated by gasdermin (GSDM) protein family. Increasing evidence indicates that pyroptosis plays an important role in multiple diseases, such as cancer, kidney diseases, inflammatory diseases, and cardiovascular diseases. Therefore, the regulation of pyroptosis is crucial for the occurrence, development, and treatment of many diseases. Hydrogen sulfide (H2S) is a biologically active gasotransmitter following carbon monoxide (CO) and nitrogen oxide (NO) in mammalian tissues. So far, three enzymes, including 3-mercaptopyruvate sulphurtransferase (3-MST), cystathionine γ- Lyase (CSE), and Cystine β-synthesis enzyme (CBS), have been found to catalyze the production of endogenous H2S in mammals. H2S has been reported to have multiple biological functions including anti-inflammation, anti-oxidative stress, anti-apoptosis and so on. Hence, H2S is involved in various physiological and pathological processes. In recent years, many studies have demonstrated that H2S plays a critical role by regulating pyroptosis in various pathological processes, such as ischemia-reperfusion injury, alcoholic liver disease, and diabetes cardiomyopathy. However, the relevant mechanism has not been completely understood. Therefore, elucidating the mechanism by which H2S regulates pyroptosis in diseases will help understand the pathogenesis of multiple diseases and provide important new avenues for the treatment of many diseases. Here, we reviewed the progress of H2S regulation of pyroptosis in different pathological processes, and analyzed the molecular mechanism in detail to provide a theoretical reference for future related research.

Targeting autophagy drug discovery: Targets, indications and development trends

Autophagy plays a vital role in sustaining cellular homeostasis and its alterations have been implicated in the etiology of many diseases. Drugs development targeting autophagy began decades ago and hundreds of agents were developed, some of which are licensed for the clinical usage. However, no existing intervention specifically aimed at modulating autophagy is available. The obstacles that prevent drug developments come from the complexity of the actual impact of autophagy regulators in disease scenarios. With the development and application of new technologies, several promising categories of compounds for autophagy-based therapy have emerged in recent years. In this paper, the autophagy-targeted drugs based on their targets at various hierarchical sites of the autophagic signaling network, e.g., the upstream and downstream of the autophagosome and the autophagic components with enzyme activities are reviewed and analyzed respectively, with special attention paid to those at preclinical or clinical trials. The drugs tailored to specific autophagy alone and combination with drugs/adjuvant therapies widely used in clinical for various diseases treatments are also emphasized. The emerging drug design and development targeting selective autophagy receptors (SARs) and their related proteins, which would be expected to arrest or reverse the progression of disease in various cancers, inflammation, neurodegeneration, and metabolic disorders, are critically reviewed. And the challenges and perspective in clinically developing autophagy-targeted drugs and possible combinations with other medicine are considered in the review.

miR-138-5p ameliorates intestinal barrier disruption caused by acute superior mesenteric vein thrombosis injury by inhibiting the NLRP3/HMGB1 axis

Background

Acute superior mesenteric venous thrombosis (ASMVT) decreases junction-associated protein expression and intestinal epithelial cell numbers, leading to intestinal epithelial barrier disruption. Pyroptosis has also recently been found to be one of the important causes of mucosal barrier defects. However, the role and mechanism of pyroptosis in ASMVT are not fully understood.

Methods

Differentially expressed microRNAs (miRNAs) in the intestinal tissues of ASMVT mice were detected by transcriptome sequencing (RNA-Seq). Gene expression levels were determined by RNA extraction and reverse transcription-quantitative PCR (RT-qPCR). Western blot and immunofluorescence staining analysis were used to analyze protein expression. H&E staining was used to observe the intestinal tissue structure. Cell Counting Kit-8 (CCK-8) and fluorescein isothiocyanate/propidine iodide (FITC/PI) were used to detect cell viability and apoptosis, respectively. Dual-luciferase reporter assays prove that miR-138-5p targets NLRP3.

Results

miR-138-5p expression was downregulated in ASMVT-induced intestinal tissues. Inhibition of miR-138-5p promoted NLRP3-related pyroptosis and destroyed tight junctions between IEC-6 cells, ameliorating ASMVT injury. miR-138-5p targeted to downregulate NLRP3. Knockdown of NLRP3 reversed the inhibition of proliferation, apoptosis, and pyroptosis and the decrease in tight junction proteins caused by suppression of miR-138-5p; however, this effect was later inhibited by overexpressing HMGB1. miR-138-5p inhibited pyroptosis, promoted intestinal epithelial tight junctions and alleviated ASMVT injury-induced intestinal barrier disruption via the NLRP3/HMGB1 axis.

Betulinic acid attenuates T-2 toxin-induced lung injury by activating Nrf2 signaling pathway and inhibiting MAPK/NF-κB signaling pathway

T-2 toxin, a type-A trichothecene mycotoxin, exists ubiquitously in mildewed foods and feeds. Betulinic acid (BA), a pentacyclic triterpenoid derived from plants, has the effect of relieving inflammation and oxidative stress. The purpose of this study was to investigate whether BA mitigates lung impairment caused by T-2 toxin and elucidate the underlying mechanism. The results indicated that T-2 toxin triggered the inflammatory cell infiltration, morphological alterations and cell apoptosis in the lungs. It is gratifying that BA ameliorated T-2 toxin-caused lung injury. The protein expression of nuclear factor erythrocyte 2-related factor 2 (Nrf2) pathway and the markers of antioxidative capability were improved in T-2 toxin induced lung injury by BA mediated protection. Simultaneously, BA supplementation could suppress T-2 toxin-induced mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB)-dependent inflammatory response and mitochondrial apoptotic pathway. Therefore, T-2 toxin gave rise to pulmonary toxicity, but these changes were moderated by BA administration through regulation of the Nrf2/MAPK/NF-κB pathway, which maybe offer a viable alternative for mitigating the lung impairments caused by the mycotoxin.

Immune Response Gene-1 [IRG1]/itaconate protect against multi-organ injury via inhibiting gasdermin D-mediated pyroptosis and inflammatory response

Sepsis is a multiple organ dysfunction syndrome due to a dysregulated response to infection with unacceptably high mortality. Currently, no effective treatment exists for sepsis. IRG1/itaconate has been considered to play a protective role for various inflammatory diseases. In the present study, we explored the protective role and mechanisms of IRG1/itaconate on lipopolysaccharide (LPS)-induced multi-organ injury. The LPS-induced sepsis model was used. IRG1-/- and wild type mice were used to explore the protective role of IRG1/itaconate on multi-organ injury. GSDMD-/- mice were used to explore the effect of GSDMD-mediated pyroptosis on LPS-induced model. RAW264.7 cells and bone-marrow-derived macrophages (BMDMs) were used for in vitro studies. In vivo experiments, we found IRG1 deficiency aggravated LPS-induced multi-organ injury especially lung injury. 4-Octyl itaconate (4-OI), a derivative of itaconate, significantly ameliorated LPS-induced acute lung, liver, and kidney injury. Furthermore, IRG1/4-OI decreased serum interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α) level, macrophage infiltration, and TUNEL-positive cells in lung and liver tissue. Western blot showed IRG1/itaconate decreased the expressions of p-ERK, p-P38, p-JNK, and p-P65 and increased the expression of Nrf2/HO-1 in lung tissue. Meanwhile, 4-OI inhibited the expression of GSDMD-N. In vitro experiments, 4-OI inhibited ROS production and promoted apoptosis under LPS stimulation in RAW264.7 cells. Furthermore, 4-OI inhibited nuclear factor-kappaB/mitogen-activated protein kinase pathways and GSDMD-medicated pyroptosis in BMDMs. Finally, we used GSDMD-/- mice to explore the effect of pyroptosis on LPS-induced multi-organ injury. The results showed that GSDMD deficiency significantly ameliorated lung injury. In conclusion, our data demonstrated that IRG1/itaconate protect against multi-organ injury via inhibiting inflammation response and GSDMD-indicated pyroptosis, which may be a promising agent for protecting against sepsis.

A narrative review on inflammaging and late-onset hypogonadism

The increasing life expectancy observed in recent years has resulted in a higher prevalence of late-onset hypogonadism (LOH) in older men. LOH is characterized by the decline in testosterone levels and can have significant impacts on physical and mental health. While the underlying causes of LOH are not fully understood, there is a growing interest in exploring the role of inflammaging in its development. Inflammaging is a concept that describes the chronic, low-grade, systemic inflammation that occurs as a result of aging. This inflammatory state has been implicated in the development of various age-related diseases. Several cellular and molecular mechanisms have been identified as contributors to inflammaging, including immune senescence, cellular senescence, autophagy defects, and mitochondrial dysfunction. Despite the extensive research on inflammaging, its relationship with LOH has not yet been thoroughly reviewed in the literature. To address this gap, we aim to review the latest findings related to inflammaging and its impact on the development of LOH. Additionally, we will explore interventions that target inflammaging as potential treatments for LOH.

Effect of injectable calcium alginate-amelogenin hydrogel on macrophage polarization and promotion of jawbone osteogenesis

Due to persistent inflammation and limited osteogenesis, jawbone defects present a considerable challenge in regenerative medicine. Amelogenin, a major protein constituent of the developing enamel matrix, demonstrates promising capabilities in inducing regeneration of periodontal supporting tissues and exerting immunomodulatory effects. These properties render it a potential therapeutic agent for enhancing jawbone osteogenesis. Nevertheless, its clinical application is hindered by the limitations of monotherapy and its rapid release characteristics, which compromise its efficacy and delivery efficiency. In this context, calcium alginate hydrogel, recognized for its superior physicochemical properties and biocompatibility, emerges as a candidate for developing a synergistic bioengineered drug delivery system. This study describes the synthesis of an injectable calcium amelogenin/calcium alginate hydrogel using calcium alginate loaded with amelogenin. We comprehensively investigated its physical properties, its role in modulating the immunological environment conducive to bone healing, and its osteogenic efficacy in areas of jawbone defects. Our experimental findings indicate that this synthesized composite hydrogel possesses desirable mechanical properties such as injectability, biocompatibility, and biodegradability. Furthermore, it facilitates jawbone formation by regulating the bone-healing microenvironment and directly inducing osteogenesis. This research provides novel insights into the development of bone-tissue regeneration materials, potentially advancing their clinical application.

Orexin-A/OX1R is involved in regulation of autophagy to promote cortisol secretion in adrenocortical cell

BACKGROUND

Hypercortisolism has emerged as a prominent clinical condition worldwide caused by biochemical cortisol excess in patients, and optimization treatment is needed urgently in the clinic. Previously, we observed that orexin-A/orexin type 1 receptor (OX1R) promoted cell proliferation, inhibited apoptosis, and increased cortisol release in adrenocortical cells. However, the functions of orexin-A/OX1R on autophagy and its molecular mechanism are not known.

METHODS

Transmission electron microscopy and confocal microscope were performed to detect autophagosomes. Western blot were performed to detect autophagy proteins. The cortisol concentration was assessed with an ELISA.

FINDINGS

Our data demonstrated that orexin-A/OX1R activated the mammalian target of rapamycin/p70 ribosomal protein S6 kinase-1 pathway, thereby inhibiting autophagy in H295R cells and Y-1 cells. Furthermore, the orexin-A/OX1R-mediated suppression of autophagy played a crucial role in cortisol secretion. Mechanistically, the expression of 3β-hydroxysteroid dehydrogenase/isomerase, the rate-limiting enzyme in cortisol synthesis, was increased with autophagy inhibition mediated by orexin-A/OX1R.

INTERPRETATION

This study provided the evidence that orexin-A/OX1R participated in modulating mTOR/p70S6K1/autophagy signaling pathway to promote cortisol secretion in adrenocortical cell. The findings suggest the mechanistic basis for disorders of cortisol secretion, providing the potential therapeutic targets for hypercortisolism treatment. FUND: This work was supported by National Natural Science Foundation of China (32170603, 31871286), the Doctoral Start-up Foundation of Liaoning Province (20180540008, 2019-BS-298), the Natural Science Foundation of Liaoning Province (2019-ZD-0779), and Shenyang Science and Technology Plan Fund Projects (21-173-9-28).

Anticancer Effect of Dihydroartemisinin via Dual Control of ROS-induced Apoptosis and Protective Autophagy in Prostate Cancer 22Rv1 Cells

BACKGROUND

Dihydroartemisinin (DHA), a natural agent, exhibits potent anticancer activity. However, its biological activity on prostate cancer (PCa) 22Rv1 cells has not been previously investigated.

OBJECTIVES

In this study, we demonstrate that DHA induces anticancer effects through the induction of apoptosis and autophagy.

METHODS

Cell viability and proliferation rate were assessed using the CCK-8 assay and cell clone formation assay. The generation of reactive oxygen species (ROS) was detected by flow cytometry. The molecular mechanism of DHA-induced apoptosis and autophagy was examined using Western blot and RT-qPCR. The formation of autophagosomes and the changes in autophagy flux were observed using transmission electron microscopy (TEM) and confocal microscopy. The effect of DHA combined with Chloroquine (CQ) was assessed using the EdU assay and flow cytometry. The expressions of ROS/AMPK/mTOR-related proteins were detected using Western blot. The interaction between Beclin-1 and Bcl-2 was examined using Co-IP.

RESULTS

DHA inhibited 22Rv1 cell proliferation and induced apoptosis. DHA exerted its antiprostate cancer effects by increasing ROS levels. DHA promoted autophagy progression in 22Rv1 cells. Inhibition of autophagy enhanced the pro-apoptotic effect of DHA. DHA-induced autophagy initiation depended on the ROS/AMPK/mTOR pathway. After DHA treatment, the impact of Beclin- 1 on Bcl-2 was weakened, and its binding with Vps34 was enhanced.

CONCLUSION

DHA induces apoptosis and autophagy in 22Rv1 cells. The underlying mechanism may involve the regulation of ROS/AMPK/mTOR signaling pathways and the interaction between Beclin-1 and Bcl-2 proteins. Additionally, the combination of DHA and CQ may enhance the efficacy of DHA in inhibiting tumor cell activity.

Role of CircCHD2 in the pathogenesis of gestational diabetes mellitus by regulating autophagy via miR-33b-3p/ULK1 axis

Gestational diabetes mellitus (GDM) is a common pregnancy complication with a high incidence in women; however, its pathophysiology remains unknown. Our previous study suggested that the circCHD2/miR-33b-3p/ULK1 axis may be involved in GDM pathogenesis. However, the mechanism through which circCHD2 regulates GDM development requires further investigation. We found that high-glucose (HG, 25 mmol/L) significantly induced the expression of circCHD2, increased autophagy and apoptosis, and decreased cell viability in human placental trophoblast HTR-8/SVneo cells. In contrast, the downregulation of circCHD2 significantly attenuated the effects of HG on HTR-8/SVneo cells. MiR-33b-3p downregulated in the placenta of GDM patients was reduced by HG and detected as a target of circCHD2 using bioinformatics analysis, a dual-luciferase reporter assay, and qRT-PCR assay. Further studies showed that the inhibition of miR-33b-3p significantly blocked the effects of circCHD2 downregulation on cell viability, apoptosis, and autophagy in HG-treated HTR-8/SVneo cells. ULK1 is a target of miR-33b-3p, based on bioinformatics analysis, a dual-luciferase reporter assay, qRT-PCR assay, and Western blot analysis. Compared to miR-33b-3p, ULK1 is upregulated in the placenta of GDM patients. ULK1 overexpression notably blocked the effects of miR-33b-3p mimics on cell viability, apoptosis, and autophagy in HG-treated HTR-8/SVneo cells. These findings suggested that circCHD2 acts as an autophagy promoter via the miR-33b-3p/ULK1 axis to induce apoptosis in HTR-8/SVneo cells, suggesting that circCHD2 is a potential diagnostic and therapeutic target for GDM.

Adrenomedullin, transcriptionally regulated by vitamin D receptors, alleviates atherosclerosis in mice through suppressing AMPK-mediated endothelial ferroptosis

PURPOSE

Vitamin D receptors (VDR) play important roles in cardiovascular, immune, metabolic and other functions. Activation of VDR may help improve endothelial dysfunction, atherosclerosis, vascular calcification, and cardiac hypertrophy. However, the specific target genes and mechanisms of VDR in improving Human Umbilical Vein Endothelial Cell (HUVEC) functions remain unclear. This study aims to investigate the function and mechanism of VDR in HUVECs.

METHODS

Endothelial dysfunction cell model was constructed by oxidized low-density lipoprotein (ox-LDL). An animal model of atherosclerosis was established in male homozygous Apoe-/- mice (6 weeks) on a high fat diet for 6 weeks. The relationship between VDR and adrenomedullin (ADM) was studied by bioinformatics analysis, ChIP, and luciferase reporter gene analysis. Endothelial cell function was evaluated by Transwell migration and Tube Formation tests. Ferroptosis was detected by measuring intracellular iron content, levels of oxidative stress markers, and ferroptosis related proteins.

RESULTS

Overexpression of VDR in HUVECs inhibits ox-LDL-induced endothelial dysfunction and ferroptosis. VDR binds to the ADM promoter sequence and regulates the transcription of ADM. Inhibition of ADM promotes ox-LDL-induced endothelial dysfunction and ferroptosis. ADM regulates ox-LDL-induced endothelial dysfunction and ferroptosis through the AMPK signaling pathway. Overexpression of VDR in Apoe-/- mice inhibited lipid deposition and plaque area in atherosclerotic mice.

CONCLUSION

VDR inhibits ox-LDL-induced endothelial dysfunction and ferroptosis by regulating ADM transcription and acting on AMPK signaling pathway. Overexpression of VDR in Apoe-/- mice reduced lipid deposition and plaque area in the thoracic aorta of atherosclerotic mice.

Pyroptosis in septic lung injury: Interactions with other types of cell death

Sepsis is a life-threatening systemic inflammatory response syndrome caused by the host imbalanced response to infection. Lung injury is the most common complication of sepsis and one of the leading causes of patient death. Pyroptosis is a specific programmed cell death characterized by the release of inflammatory cytokines. Appropriate pyroptosis can reduce tissue damage and exert a protective effect against infection during sepsis. However, overactivated pyroptosis results in massive cell death, leading to septic shock, multiple organ dysfunction syndrome, and even an increased risk of secondary infection. Recent studies suggest that pyroptosis can interact with and cross-regulate other types of cell death programs to establish a complex network of cell death, which participates in the occurrence and development of septic lung injury. This review will focus on the interactions between pyroptosis and other types of cell death, including apoptosis, necroptosis, PANoptosis, NETosis, autophagy, and ferroptosis, to summarize the role of pyroptosis in sepsis-induced lung injury, and will discuss the potential therapeutic strategies of targeting pyroptosis during sepsis treatment.

Exosomes from adipose-derived stem cells alleviate premature ovarian failure via blockage of autophagy and AMPK/mTOR pathway

Objective

The objective of this study was to investigate the effects and mechanisms of adipose-derived stem cell-derived exosome (ADSCs-Exo) in treating premature ovarian failure (POF).

Methods

We constructed a POF mouse model through intraperitoneal injection of cyclophosphamide, followed by the administration of the autophagy inhibitor 3-methyladenine (3-MA). Pathological injury, follicle stimulating hormone (FSH), malondialdehyde (MDA), reactive oxygen species (ROS), estradiol (E2), superoxide dismutase (SOD), granulosa cell (GC) apoptosis, and autophagy were assessed. Exosomes isolated from ADSCs were used to treat POF in mice. The AMPK-mTOR pathway and its proteins (p-AMPK and p-mTOR) were evaluated. A POF cell model was established using cyclophosphamide-treated human ovarian granulosa-like tumor (KGN) cells. We administered ADSCs-Exo and rapamycin to validate the mechanism of ADSCs-Exo against POF.

Results

In POF mice, 3-MA treatment attenuated pathological injuries, decreased FSH, MDA, and ROS levels, and increased E2 and SOD levels. 3-MA treatment also inhibited GC apoptosis and autophagy. ADSCs-Exo alleviated pathological injuries, improved ovarian morphology and function, and reduced oxidative stress in POF mice. ADSCs-Exo inhibited GC apoptosis and autophagy. ADSCs-Exo downregulated the expression of AMPK/mTOR pathway proteins (p-AMPK and p-mTOR). In the POF cell model, ADSCs-Exo and rapamycin inhibited AMPK/mTOR-mediated autophagy.

Conclusion

ADSCs-Exo inhibits POF through the inhibition of autophagy and the AMPK/mTOR pathway. This study provides a potential target for the clinical treatment of POF.

Mec1-Rad53 Signaling Regulates DNA Damage-Induced Autophagy and Pathogenicity in Candida albicans

DNA damage activates the DNA damage response and autophagy in C. albicans; however, the relationship between the DNA damage response and DNA damage-induced autophagy in C. albicans remains unclear. Mec1-Rad53 signaling is a critical pathway in the DNA damage response, but its role in DNA damage-induced autophagy and pathogenicity in C. albicans remains to be further explored. In this study, we compared the function of autophagy-related (Atg) proteins in DNA damage-induced autophagy and traditional macroautophagy and explored the role of Mec1-Rad53 signaling in regulating DNA damage-induced autophagy and pathogenicity. We found that core Atg proteins are required for these two types of autophagy, while the function of Atg17 is slightly different. Our results showed that Mec1-Rad53 signaling specifically regulates DNA damage-induced autophagy but has no effect on macroautophagy. The recruitment of Atg1 and Atg13 to phagophore assembly sites (PAS) was significantly inhibited in the mec1Δ/Δ and rad53Δ/Δ strains. The formation of autophagic bodies was obviously affected in the mec1Δ/Δ and rad53Δ/Δ strains. We found that DNA damage does not induce mitophagy and ER autophagy. We also identified two regulators of DNA damage-induced autophagy, Psp2 and Dcp2, which regulate DNA damage-induced autophagy by affecting the protein levels of Atg1, Atg13, Mec1, and Rad53. The deletion of Mec1 or Rad53 significantly reduces the ability of C. albicans to systematically infect mice and colonize the kidneys, and it makes C. albicans more susceptible to being killed by macrophages.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

Cypermethrin induces endoplasmic reticulum stress and autophagy, leads to testicular dysfunction

Cypermethrin is a pyrethroid insecticide that is used to control insects and protect crops. However, pesticide residues and their possible toxicity to non-target animals such as mammals are concerning. Although cypermethrin reduces testosterone levels, the molecular mechanisms involved, particularly those regarding endoplasmic reticulum (ER) stress and autophagy regulation, have not yet been fully elucidated. In this study, we demonstrated testicular toxicity of cypermethrin in mouse Leydig (TM3) and Sertoli (TM4) cells. Cypermethrin suppresses TM3 and TM4 cell proliferation and induces apoptosis. Moreover, it interrupted calcium homeostasis in intracellular organelles and dissipated mitochondrial membrane polarization in mouse testicular cells. Moreover, we verified the accumulation of Sqstm1/p62 protein in the mitochondria of cypermethrin-treated TM3 and TM4 cells. Furthermore, we confirmed that cypermethrin activated autophagy and the ER stress pathway in a time-dependent manner in both cell types. Finally, we determined that cypermethrin downregulated testicular function-related genes, steroidogenesis, and spermatogenesis in mouse testis cells. Therefore, we conclude that cypermethrin regulates autophagy and ER stress, leading to testicular dysfunction.

Depletion of mTOR ameliorates CD4+ T cell pyroptosis by promoting autophagy activity in septic mice

A reduction in the number of CD4+ T cells is a central part of the immunosuppression phase of sepsis and leads to impaired immune defense ability and increased mortality. Pyroptosis, a newly discovered programmed cell death, was confirmed to be an important mechanism of lymphocytopenia in a lot of human diseases and is under the regulation of autophagy. The mammalian target of rapamycin (mTOR) pathway is closely related to CD4+ T-cell survival. Whether the mTOR pathway influences CD4+ T cell pyroptosis by regulating autophagy remains unknown. In this study, a septic mouse model was developed using cecal ligation and puncture (CLP) to explore the degree of pyroptosis and autophagy of CD4+ T cells. T-cell-specific mTOR/TSC1-knockout mice were used to investigate the role of mTOR pathway in the regulation of CD4+ T cell pyroptosis. Bafilomycin, a specific autophagy inhibitor, was used to verify the regulatory effect of autophagy on pyroptosis in septic mice. We observed aggravated pyroptosis in CD4+ T cells in CLP mice accompanied by impaired autophagy activity and an overactivated mTOR signaling pathway. Depletion of mTOR relieved autophagy deficiency and reduced the proportion of pyroptotic CD4+ T cells. In T-cell-specific mTOR-knockout mice treated with bafilomycin, the protective effect of mTOR depletion vanished. This indicated that autophagy negatively regulates CD4+ T cell pyroptosis, which is under the control of the mTOR pathway. Taken together, our findings emphasize the importance of pyroptosis in sepsis-induced lymphopenia and reveal the regulatory effects of the mTOR pathway and the role of autophagy in this regulation.

Reciprocal interaction between mitochondrial fission and mitophagy in postoperative delayed neurocognitive recovery in aged rats

INTRODUCTION

Emerging evidence suggests that mitochondrial dysfunction plays a crucial role in the pathogenesis of postoperative delayed neurocognitive recovery (dNCR). Mitochondria exist in a dynamic equilibrium that involves fission and fusion to regulate morphology and maintains normal cell function via the removal of damaged mitochondria through mitophagy. Nonetheless, the relationship between mitochondrial morphology and mitophagy, and how they influence mitochondrial function in the development of postoperative dNCR, remains poorly understood. Here, we observed morphological alterations of mitochondria and mitophagy activity in hippocampal neurons and assessed the involvement of their interaction in dNCR following general anesthesia and surgical stress in aged rats.

METHODS

Firstly, we evaluated the spatial learning and memory ability of the aged rats after anesthesia/surgery. Hippocampal mitochondrial function and mitochondrial morphology were detected. Afterwards, mitochondrial fission was inhibited by Mdivi-1 and siDrp1 in vivo and in vitro separately. We then detected mitophagy and mitochondrial function. Finally, we used rapamycin to activate mitophagy and observed mitochondrial morphology and mitochondrial function.

RESULTS

Surgery impaired hippocampal-dependent spatial learning and memory ability and caused mitochondrial dysfunction. It also increased mitochondrial fission and inhibited mitophagy in hippocampal neurons. Mdivi-1 improved mitophagy and learning and memory ability of aged rats by inhibiting mitochondrial fission. Knocking down Drp1 by siDrp1 also improved mitophagy and mitochondrial function. Meanwhile, rapamycin inhibited excessive mitochondrial fission and improved mitochondrial function.

CONCLUSION

Surgery simultaneously increases mitochondrial fission and inhibits mitophagy activity. Mechanistically, mitochondrial fission/fusion and mitophagy activity interact reciprocally with each other and are both involved in postoperative dNCR. These mitochondrial events after surgical stress may provide novel targets and modalities for therapeutic intervention in postoperative dNCR.

Establishment of a novel indicator of pyroptosis regulated gene transcription level and its application in pan-cancer

Pyroptosis is a type of programmed cell death and plays a dual role in distinct cancers. It is elusive to evaluate the activation level of pyroptosis and to appraise the involvement of pyroptosis in the occurrence and development of diverse tumors. Accordingly, we herein established an indicator to evaluate pyroptosis related gene transcription levels based on the expression level of genes involved in pyroptosis and tried to elaborated on the association between pyroptosis and tumors across diverse tumor types. We found that pyroptosis related gene transcription levels could predict the prognosis of patients, which could act as either a favorable or a dreadful factor in diverse cancers. According to signaling pathway analyses we observed that pyroptosis played a significant role in immune regulation and tumorigenesis and had strong links with other forms of cell death. We also performed analysis on the crosstalk between pyroptosis and immune status and further investigated the predictive potential of pyroptosis level for the efficacy of immunotherapy. Lastly, we manifested that pyroptosis status could serve as a biomarker to the efficacy of chemotherapy across various cancers. In summary, this study established a quantitative indicator to evaluate pyroptosis related gene transcription levels, systematically explored the role of pyroptosis in pan-cancer. These results could provide potential research directions targeting pyroptosis, and highlighted that pyroptosis may be used to develop a novel strategy for the treatment of cancer.

α-Linolenic acid-regulated testosterone biosynthesis via activation of the JNK-SF-1 signaling pathway in primary rooster Leydig cells

As a functional fatty acid, α-linolenic acid (ALA) is essential in promoting animal testosterone biosynthesis. This study investigated the effects of ALA on testosterone biosynthesis and the possible mechanism underlying the signaling pathway in primary Leydig cells of the rooster.

METHODS

Primary rooster Leydig cells were treated with ALA (0, 20, 40, or 80 μmol/L) or pretreated with a p38 inhibitor (50 μmol/L), a c-Jun NH2-terminal kinase (JNK) inhibitor (20 μmol/L), or an extracellular signal-regulated kinase (ERK) inhibitor (20 μmol/L) before ALA treatment. Testosterone content in the conditioned culture medium was detected using an enzyme-linked immunosorbent assay (ELISA). The expression of steroidogenic enzymes and JNK-SF-1 signaling pathway factors was detected using real-time fluorescence quantitative PCR (qRT-PCR).

RESULTS

Supplementation with ALA significantly increased testosterone secretion within culture media (P < 0.05), and the optimized dose was 40 μmol/L. Compared with the control group, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA expression significantly increased (P < 0.05) in the 40 μmol/L ALA group; 17-hydroxylase/c17-20 lyase (P450c17) and p38 mRNA expressions were not significantly different in the 40 μmol/L ALA group; ERK and JNK mRNA expressions were significantly upregulated (P < 0.05) in 40 μmol/L ALA group. In the inhibitor group, testosterone levels were significantly downregulated (P < 0.05). Compared with the 40 μmol/L ALA group, StAR, P450scc, and P450c17 mRNA expressions were significantly decreased (P < 0.05), and 3β-HSD mRNA expression in the p38 inhibitor group did not change; StAR, P450scc, and 3β-HSD mRNA expressions were significantly decreased (P < 0.05), and P450c17 mRNA expression in ERK inhibitor group did not change; StAR, P450scc, 3β-HSD, and P450c17 mRNA expressions were significantly decreased (P < 0.05) in JNK inhibitor group. Additionally, the increased steroidogenic factor 1 (SF-1) gene expression levels induced by ALA were reversed when the cells were pre-incubated with JNK and ERK inhibitors. The levels in the JNK inhibitor group were significantly lower than those in the control group (P < 0.05).

CONCLUSION

ALA may promote testosterone biosynthesis by activating the JNK-SF-1 signaling pathway to upregulate StAR, P450scc, 3β-HSD, and P450c17 expression in primary rooster Leydig cells.

Exosomes derived from human umbilical cord mesenchymal stem cells alleviate Parkinson's disease and neuronal damage through inhibition of microglia

Microglia-mediated inflammatory responses have been shown to play a crucial role in Parkinson's disease. In addition, exosomes derived from mesenchymal stem cells have shown anti-inflammatory effects in the treatment of a variety of diseases. However, whether they can protect neurons in Parkinson's disease by inhibiting microglia-mediated inflammatory responses is not yet known. In this study, exosomes were isolated from human umbilical cord mesenchymal stem cells and injected into a 6-hydroxydopamine-induced rat model of Parkinson's disease. We found that the exosomes injected through the tail vein and lateral ventricle were absorbed by dopaminergic neurons and microglia on the affected side of the brain, where they repaired nigral-striatal dopamine system damage and inhibited microglial activation. Furthermore, in an in vitro cell model, pretreating lipopolysaccharide-stimulated BV2 cells with exosomes reduced interleukin-1β and interleukin-18 secretion, prevented the adoption of pyroptosis-associated morphology by BV2 cells, and increased the survival rate of SH-SY5Y cells. Potential targets for treatment with human umbilical cord mesenchymal stem cells and exosomes were further identified by high-throughput microRNA sequencing and protein spectrum sequencing. Our findings suggest that human umbilical cord mesenchymal stem cells and exosomes are a potential treatment for Parkinson's disease, and that their neuroprotective effects may be mediated by inhibition of excessive microglial proliferation.

Ursolic Acid Promotes Autophagy by Inhibiting Akt/mTOR and TNF-α/TNFR1 Signaling Pathways to Alleviate Pyroptosis and Necroptosis in Mycobacterium tuberculosis-Infected Macrophages

As a lethal infectious disease, tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb). Its complex pathophysiological process limits the effectiveness of many clinical treatments. By regulating host cell death, Mtb manipulates macrophages, the first line of defense against invading pathogens, to evade host immunity and promote the spread of bacteria and intracellular inflammatory substances to neighboring cells, resulting in widespread chronic inflammation and persistent lung damage. Autophagy, a metabolic pathway by which cells protect themselves, has been shown to fight intracellular microorganisms, such as Mtb, and they also play a crucial role in regulating cell survival and death. Therefore, host-directed therapy (HDT) based on antimicrobial and anti-inflammatory interventions is a pivotal adjunct to current TB treatment, enhancing anti-TB efficacy. In the present study, we showed that a secondary plant metabolite, ursolic acid (UA), inhibited Mtb-induced pyroptosis and necroptosis of macrophages. In addition, UA induced macrophage autophagy and enhanced intracellular killing of Mtb. To investigate the underlying molecular mechanisms, we explored the signaling pathways associated with autophagy as well as cell death. The results showed that UA could synergistically inhibit the Akt/mTOR and TNF-α/TNFR1 signaling pathways and promote autophagy, thus achieving its regulatory effects on pyroptosis and necroptosis of macrophages. Collectively, UA could be a potential adjuvant drug for host-targeted anti-TB therapy, as it could effectively inhibit pyroptosis and necroptosis of macrophages and counteract the excessive inflammatory response caused by Mtb-infected macrophages via modulating the host immune response, potentially improving clinical outcomes.

Identification of a novel pyroptosis-related gene signature in human spermatogenic dysfunction

PURPOSE

To reveal the underlying roles that pyroptosis-related genes (PRGs) played in human spermatogenic dysfunction.

METHODS

One discovery set and three validation sets were employed to inspect the previously reported 33 PRGs in the human testis with different status of spermatogenesis. PRGs that differentially expressed in all sets were considered as key differentially expressed pyroptosis-related genes (PR-DEGs). The relationships between key PR-DEGs and samples' clinicopathological, therapeutic, and immune patterns were respectively studied. Single-cell RNA sequencing (scRNS-seq) analyses were conducted to show the expression changes and related mechanisms of key PR-DEGs at a single-cell resolution.

RESULTS

CASP4 and GPX4 were identified as two key PR-DEGs. These two genes were significantly dysregulated in spermatogenic dysfunctional samples, but with opposite tendency. CASP4 was negatively correlated with Johnsen scores but positively correlated with follicle-stimulating hormone (FSH) levels (all p < 0.05), while GPX4 exhibited significant positive correlations with Johnsen scores and negative relevance with FSH. For treatments, both molecules showed a prospective value of being predictors for sperm retrieval surgeries. Moreover, CASP4 and GPX4 were potential immunoregulators in the testicular immune microenvironment and showed significant correlations to testicular macrophages and mast cell infiltration. In scRNA-seq analyses, GPX4 was highly expressed in germ cells, which therefore suffered a sharp reduction with the loss of germ cells in spermatogenic dysfunction. On the other hand, CASP4 were basically somatic cell-derived, and the proportion of CASP4-positive Leydig cells significantly increased in disease testes (p = 0.0001).

CONCLUSION

In all, we revealed two key PRGs of human testes that might be functional in spermatogenic dysfunction.

Impacts and potential mechanisms of fine particulate matter (PM2.5) on male testosterone biosynthesis disruption

Exposure to PM2.5 is the most significant air pollutant for health risk. The testosterone level in male is vulnerable to environmental toxicants. In the past, researchers focused more attention on the impacts of PM2.5 on respiratory system, cardiovascular system, and nervous system, and few researchers focused attention on the reproductive system. Recent studies have reported that PM2.5 involved in male testosterone biosynthesis disruption, which is closely associated with male reproductive health. However, the underlying mechanisms by which PM2.5 causes testosterone biosynthesis disruption are still not clear. To better understand its potential mechanisms, we based on the existing scientific publications to critically and comprehensively reviewed the role and potential mechanisms of PM2.5 that are participated in testosterone biosynthesis in male. In this review, we summarized the potential mechanisms of PM2.5 triggering the change of testosterone level in male, which involve in oxidative stress, inflammatory response, ferroptosis, pyroptosis, autophagy and mitophagy, microRNAs (miRNAs), endoplasmic reticulum (ER) stress, and N6-methyladenosine (m6A) modification. It will provide new suggestions and ideas for prevention and treatment of testosterone biosynthesis disruption caused by PM2.5 for future research.

3,5-diCQA suppresses colorectal cancer cell growth through ROS/AMPK/mTOR mediated mitochondrial dysfunction and ferroptosis

3,5-diCQA has been shown to have anti-tumor effect by decreasing cancer cell growth. However, the molecular mechanism by which 3,5-diCQA impacts colorectal cancer (CRC) cells is unknown. This study discovered that 3,5-diCQA had a suppressive effect on CRC cells, mainly in the inhibition of proliferation, migration, and the enhancement of apoptosis in HCT116 and SW480 cells. Additionally, 3,5-diCQA was found to cause cell cycle arrest in CRC cells. Meanwhile, we found that 3,5-diCQA activates the AMPK pathway through the generation of ROS, mediates mitochondrial damage, and reduces mitochondrial aerobic glycolysis and oxidative phosphorylation levels. 3,5-diCQA promoted oxidative damage and ferroptosis in CRC cells. Hence, we added ROS inhibitor NAC and found that the NAC reversed the effects of 3,5-diCQA on proliferation, apoptosis, ROS generation, and ferroptosis in CRC cells. Moreover, 3,5-diCQA was also shown to suppress the development of CRC tumor in a tumor-forming model of nude mice. In conclusion, we found that 3,5-diCQA enhances the oxidative damage and ferroptosis while reducing proliferation and migration of CRC cells, depending on mitochondrial dysfunction caused by the ROS/AMPK/mTOR pathway.

The mechanistic role of cardiac glycosides in DNA damage response and repair signaling

Cardiac glycosides (CGs) are a class of bioactive organic compounds well-known for their application in treating heart disease despite a narrow therapeutic window. Considerable evidence has demonstrated the potential to repurpose CGs for cancer treatment. Chemical modification of these CGs has been utilized in attempts to increase their anti-cancer properties; however, this has met limited success as their mechanism of action is still speculative. Recent studies have identified the DNA damage response (DDR) pathway as a target of CGs. DDR serves to coordinate numerous cellular pathways to initiate cell cycle arrest, promote DNA repair, regulate replication fork firing and protection, or induce apoptosis to avoid the survival of cells with DNA damage or cells carrying mutations. Understanding the modus operandi of cardiac glycosides will provide critical information to better address improvements in potency, reduced toxicity, and the potential to overcome drug resistance. This review summarizes recent scientific findings of the molecular mechanisms of cardiac glycosides affecting the DDR signaling pathway in cancer therapeutics from 2010 to 2022. We focus on the structural and functional differences of CGs toward identifying the critical features for DDR targeting of these agents.

Three-Dimensional Matrix Stiffness Activates the Piezo1-AMPK-Autophagy Axis to Regulate the Cellular Osteogenic Differentiation

Extracellular matrix (ECM) stiffness is a key stimulus affecting cellular differentiation, and osteoblasts are also in a three-dimensional (3D) stiff environment during the formation of bone tissues. However, it remains unclear how cells perceive matrix mechanical stiffness stimuli and translate them into intracellular signals to affect differentiation. Here, for the first time, we constructed a 3D culture environment by GelMA hydrogels with different amino substitution degrees and found that Piezo1 expression was significantly stimulated by the stiff matrix with high substitution; meanwhile, the expressions of osteogenic markers OSX, RUNX2, and ALP were also observably improved. Moreover, knockdown of Piezo1 in the stiff matrix revealed significant reduction of the abovementioned osteogenic markers. In addition, in this 3D biomimetic ECM, we also observed that Piezo1 can be activated by the static mechanical conditions of the stiff matrix, leading to the increase of the intracellular calcium content and accompanied with a continuous change in cellular energy levels as ATP was consumed during cellular differentiation. More surprisingly, we found that in the 3D stiff matrix, intracellular calcium as a second messenger promoted the activation of the AMP-activated protein kinase (AMPK) and unc-51-like autophagy-activated kinase 1 (ULK1) axis and modestly modulated the level of autophagy, bringing it more similar to differentiated osteoblasts, with increased ATP energy metabolism consumption. Our study innovatively clarifies the regulatory role of the mechanosensitive ion channel Piezo1 in a static mechanical environment on cellular differentiation and verifies the activation of the AMPK-ULK1 axis in the cellular ATP energy metabolism and autophagy level. Collectively, our research develops the understanding of the interaction mechanisms of biomimetic extracellular matrix biomaterials and cells from a novel perspective and provides a theoretical basis for bone regeneration biomaterials design and application.

An update on the bridging factors connecting autophagy and Nrf2 antioxidant pathway

Macroautophagy/autophagy is a lysosome-dependent catabolic pathway for the degradation of intracellular proteins and organelles. Autophagy dysfunction is related to many diseases, including lysosomal storage diseases, cancer, neurodegenerative diseases, cardiomyopathy, and chronic metabolic diseases, in which increased reactive oxygen species (ROS) levels are also observed. ROS can randomly oxidize proteins, lipids, and DNA, causing oxidative stress and damage. Cells have developed various antioxidant pathways to reduce excessive ROS and maintain redox homeostasis. Treatment targeting only one aspect of diseases with autophagy dysfunction and oxidative stress shows very limited effects. Herein, identifying the bridging factors that can regulate both autophagy and antioxidant pathways is beneficial for dual-target therapies. This review intends to provide insights into the current identified bridging factors that connect autophagy and Nrf2 antioxidant pathway, as well as their tight interconnection with each other. These factors could be potential dual-purpose targets for the treatment of diseases implicated in both autophagy dysfunction and oxidative stress.