Endonuclease G promotes autophagy by suppressing mTOR signaling and activating the DNA damage response

Molecular mechanism on autophagy associated cardiovascular dysfunction in Drosophila melanogaster

As a highly conserved cellular process, autophagy has been the focus of extensive research due to its critical role in maintaining cellular homeostasis and its implications in cardiovascular pathogenesis. The decline in muscular function, along with the neuronal system, and increased sensitivity to stress have been recognized in multiple animal models. Autophagic defects in cardiovascular architecture and cellular dysfunction have been linked to both physiological and pathological conditions of the heart in mammals and Drosophila. In this review, we systematically analyze the autophagy-associated pathways in the hearts of fruit flies and aim to provide a comprehensive understanding for developing potential treatments for patients and effective strategies for agricultural applications. This analysis elucidates the molecular mechanisms of autophagy in cardiovascular function under both physiological and pathological conditions in Drosophila, offering significant insights into the development of cardiovascular diseases. The loss of key autophagy-associated proteins, including the transmembrane protein Atg9 and its partners Atg2 or Atg18, along with DmSestrin, leads to cardiac hypertrophy and structural abnormalities in Drosophila, resembling the age-dependent deterioration of cardiac function. Members of the autophagy-related (Atg) gene family, cellular or nuclear skeletal lamins, and the mechanistic or mammalian target of rapamycin (mTOR) signaling pathways are critically influential in heart function in Drosophila, with autophagy activation shown to suppress cardiac laminopathy. The mTORC1/C2 complexes, along with axis of Atg2-AMPK/Sirt1/PGC-1α pathway, are essential in the hearts of both mammals and fruit flies, governing cardiac development, growth, maturation, and the maintenance of cardiac homeostasis. The beneficial effects of several interventions that enhance cardiac function, including exercise and cold stress, can influence autophagy-dependent TOR activity of the serine/threonine protein kinase signaling in both mammals and Drosophila. Exercise has been shown to increase autophagy when it is deficient and to inhibit it when it is excessive, highlighting the dual role of autophagy in cardiac health. This review evaluates the functional significance of autophagy in the heart, particularly in the context of Drosophila, in relation to mTORC-associated autophagy and the axis of Atg2-AMPK/Sirt1/PGC-1α pathways. It systematically contrasts the molecular mechanisms underlying autophagy-related cardiovascular physiological and pathological conditions in both fruit flies and mammals. The evolutionary conservation of autophagy underscores the value of Drosophila as a model for understanding broader mechanisms of autophagy across species. This study not only deepens our understanding of autophagy's role in cardiovascular function but also provides a theoretical foundation for the potential application of autophagy in agricultural pest control.

Transcriptional regulation of autophagy in skeletal muscle stem cells

Muscle stem cells (MuSCs) are essential for the regenerative capabilities of skeletal muscles. MuSCs are maintained in a quiescent state, but, when activated, can undergo proliferation and differentiation into myocytes, which fuse and mature to generate muscle fibers. The maintenance of MuSC quiescence and MuSC activation are processes that are tightly regulated by autophagy, a conserved degradation system that removes unessential or dysfunctional cellular components via lysosomes. Both the upregulation and downregulation of autophagy have been linked to impaired muscle regeneration, causing myopathies such as cancer cachexia, sarcopenia and Duchenne muscular dystrophy. In this Review, we highlight the importance of autophagy in regulating MuSC activity during muscle regeneration. Additionally, we summarize recent studies that link the transcriptional dysregulation of autophagy to muscle atrophy, emphasizing the dominant roles that transcription factors play in myogenic programs. Deciphering and understanding the roles of these transcription factors in the regulation of autophagy during myogenesis could advance the development of regenerative medicine.

Class III Phosphatidylinositol-3 Kinase/Vacuolar Protein Sorting 34 in Cardiovascular Health and Disease

Phosphatidylinositol-3 kinases (PI3Ks) play a critical role in maintaining cardiovascular health and the development of cardiovascular diseases (CVDs). Specifically, vacuolar Protein Sorting 34 (VPS34) or PIK3C3, the only member of Class III PI3K, plays an important role in CVD progression. The main function of VPS34 is inducing the production of phosphatidylinositol 3-phosphate, which, together with other essential structural and regulatory proteins in forming VPS34 complexes, further regulates the mammalian target of rapamycin activation, autophagy, and endocytosis. VPS34 is found to have crucial functions in the cardiovascular system, including dictating the proliferation and survival of vascular smooth muscle cells and cardiomyocytes and the formation of thrombosis. This review aims to summarize our current knowledge and recent advances in understanding the function and regulation of VPS34 in cardiovascular health and disease. We also discuss the current development of VPS34 inhibitors and their potential to treat CVDs.

Polymorphisms within autophagy-related genes as susceptibility biomarkers for pancreatic cancer: A meta-analysis of three large European cohorts and functional characterization

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers with patients having unresectable or metastatic disease at diagnosis, with poor prognosis and very short survival. Given that genetic variation within autophagy-related genes influences autophagic flux and susceptibility to solid cancers, we decided to investigate whether 55,583 single nucleotide polymorphisms (SNPs) within 234 autophagy-related genes could influence the risk of developing PDAC in three large independent cohorts of European ancestry including 12,754 PDAC cases and 324,926 controls. The meta-analysis of these populations identified, for the first time, the association of the BIDrs9604789 variant with an increased risk of developing the disease (ORMeta = 1.31, p = 9.67 × 10-6). We also confirmed the association of TP63rs1515496 and TP63rs35389543 variants with PDAC risk (OR = 0.89, p = 6.27 × 10-8 and OR = 1.16, p = 2.74 × 10-5). Although it is known that BID induces autophagy and TP63 promotes cell growth, cell motility and invasion, we also found that carriers of the TP63rs1515496G allele had increased numbers of FOXP3+ Helios+ T regulatory cells and CD45RA+ T regulatory cells (p = 7.67 × 10-4 and p = 1.56 × 10-3), but also decreased levels of CD4+ T regulatory cells (p = 7.86 × 10-4). These results were in agreement with research suggesting that the TP63rs1515496 variant alters binding sites for FOXA1 and CTCF, which are transcription factors involved in modulating specific subsets of regulatory T cells. In conclusion, this study identifies BID as new susceptibility locus for PDAC and confirms previous studies suggesting that the TP63 gene is involved in the development of PDAC. This study also suggests new pathogenic mechanisms of the TP63 locus in PDAC.

Endonuclease G promotes hepatic mitochondrial respiration by selectively increasing mitochondrial tRNAThr production

Mitochondrial endonuclease G (EndoG) contributes to chromosomal degradation when it is released from mitochondria during apoptosis. It is presumed to also have a mitochondrial function because EndoG deficiency causes mitochondrial dysfunction. However, the mechanism by which EndoG regulates mitochondrial function is not known. Fat accumulation in metabolic dysfunction-associated steatotic liver disease (MASLD), which is more common in men, is caused in part by mitochondrial dysfunction. EndoG expression is reduced in MASLD liver, and EndoG deficiency causes MASLD in an obesity-independent manner but only in males. EndoG promotes mitochondrial respiration by resolving mitochondrial tRNA/DNA hybrids formed during mtDNA transcription by recruiting RNA helicase DHX30 to unwind them. EndoG also cleaves off the 3'-end of the H-strand transcript that can prevent mt-tRNAThr precursor cloverleaf-folding, and processing, which increases mt-tRNAThr production and mitochondrial translation. Using fluorescent lifetime imaging microscopy technology to visualize oxygen consumption at the individual mitochondrion level, we found that EndoG deficiency leads to the selective loss of a mitochondrial subpopulation with high-oxygen consumption. This defect was reversed with mt-tRNAThr supplementation. Thus, EndoG promotes mitochondrial respiration by selectively regulating the production of mt-tRNAThr in male mice.

Epigallocatechin gallate improves oleic acid-induced hepatic steatosis in laying hen hepatocytes via the MAPK pathway

Fatty liver disease in laying hens, characterized by excessive lipid accumulation in hepatocytes, poses significant challenges to poultry health and production efficiency. In this study, we investigated the therapeutic potential of epigallocatechin gallate (EGCG), a bioactive compound found in green tea, in mitigating oleic acid (OA)-induced hepatic steatosis in primary chicken hepatocytes. Treatment with EGCG effectively attenuated lipid deposition by downregulating lipid synthesis-related genes. Moreover, EGCG mitigated oxidative stress, inflammation, DNA damage, and apoptosis induced by OA, thereby preserving hepatocyte viability. Mechanistically, EGCG exerted its protective effects by modulating the p38 MAPK signaling pathway. Our findings suggest that EGCG holds promise as a therapeutic agent for managing fatty liver disease in poultry, offering insights into novel strategies for improving poultry health and production outcomes.

Combating wheat yellow mosaic virus through microbial interactions and hormone pathway modulations

BACKGROUND

The rhizosphere microbiome is critical for promoting plant growth and mitigating soil-borne pathogens. However, its role in fighting soil-borne virus-induced diseases, such as wheat yellow mosaic virus (WYMV) transmitted by Polymyxa graminis zoospores, remains largely underexplored. In this study, we hypothesized that during viral infections, plant microbiomes engage in critical interactions with plants, with key microbes playing vital roles in maintaining plant health. Our research aimed to identify microbial taxa that not only suppress the disease but also boost wheat yield by using a blend of techniques, including field surveys, yield assessments, high-throughput sequencing of plant and soil microbiomes, microbial isolation, hydroponic experiments, and transcriptome sequencing.

RESULTS

We found that, compared with roots and leaves, the rhizosphere microbiome showed a better performance in predicting wheat yield and the prevalence of P. graminis and WYMV across the three WYMV-impacted regions in China. Using machine learning, we found that healthy rhizospheres were marked with potentially beneficial microorganisms, such as Sphingomonas and Allorhizobium-Neorhizobium-Parararhizobium-Rhizobium, whereas diseased rhizospheres were associated with a higher prevalence of potential pathogens, such as Bipolaris and Fusicolla. Structural equation modeling showed that these biomarkers both directly and indirectly impacted wheat yield by modulating the rhizosphere microbiome and P. graminis abundance. Upon re-introduction of two key healthy rhizosphere biomarkers, Sphingomonas azotifigens and Rhizobium deserti, into the rhizosphere, wheat growth and health were enhanced. This was attributed to the up-regulation of auxin and cytokinin signaling pathways and the regulation of jasmonic acid and salicylic acid pathways during infections.

CONCLUSIONS

Overall, our study revealed the critical role of the rhizosphere microbiome in combating soil-borne viral diseases, with specific rhizosphere microbes playing key roles in this process. Video Abstract.

Premature senescence is regulated by crosstalk among TFEB, the autophagy lysosomal pathway and ROS derived from damaged mitochondria in NaAsO2-exposed auditory cells

Age-related hearing loss (ARHL) is one of the most prevalent types of sensory decline in a superaging society. Although various studies have focused on the effect of oxidative stress on the inner ear as an inducer of ARHL, there are no effective preventive approaches for ARHL. Recent studies have suggested that oxidative stress-induced DNA damage responses (oxidative DDRs) drive cochlear cell senescence and contribute to accelerated ARHL, and autophagy could function as a defense mechanism against cellular senescence in auditory cells. However, the underlying mechanism remains unclear. Sodium arsenite (NaAsO2) is a unique oxidative stress inducer associated with reactive oxygen species (ROS) that causes high-tone hearing loss similar to ARHL. Transcription factor EB (TFEB) functions as a master regulator of the autophagy‒lysosome pathway (ALP), which is a potential target during aging and the pathogenesis of various age-related diseases. Here, we focused on the function of TFEB and the impact of intracellular ROS as a potential target for ARHL treatment in a NaAsO2-induced auditory premature senescence model. Our results suggested that short exposure to NaAsO2 leads to DNA damage, lysosomal damage and mitochondrial damage in auditory cells, triggering temporary signals for TFEB transport into the nucleus and, as a result, causing insufficient autophagic flux and declines in lysosomal function and biogenesis and mitochondrial quality. Then, intracellular ROS derived from damaged mitochondria play a role as a second messenger to induce premature senescence in auditory cells. These findings suggest that TFEB activation via transport into the nucleus contributes to anti-senescence activity in auditory cells and represents a new therapeutic target for ARHL. We have revealed the potential function of TFEB as a master regulator of the induction of oxidative stress-induced premature senescence and the senescence-associated secretion phenotype (SASP) in auditory cells, which regulates ALP and controls mitochondrial quality through ROS production.

All Roads Lead to Rome: Comparing Nanoparticle- and Small Molecule-Driven Cell Autophagy

Autophagy, vital for removing cellular waste, is triggered differently by small molecules and nanoparticles. Small molecules, like rapamycin, non-selectively activate autophagy by inhibiting the mTOR pathway, which is essential for cell regulation. This can clear damaged components but may cause cytotoxicity with prolonged use. Nanoparticles, however, induce autophagy, often causing oxidative stress, through broader cellular interactions and can lead to a targeted form known as "xenophagy." Their impact varies with their properties but can be harnessed therapeutically. In this review, the autophagy induced by nanoparticles is explored and small molecules across four dimensions: the mechanisms behind autophagy induction, the outcomes of such induction, the toxicological effects on cellular autophagy, and the therapeutic potential of employing autophagy triggered by nanoparticles or small molecules. Although small molecules and nanoparticles each induce autophagy through different pathways and lead to diverse effects, both represent invaluable tools in cell biology, nanomedicine, and drug discovery, offering unique insights and therapeutic opportunities.

Endonuclease G is dispensable for sperm mitochondrial DNA elimination during spermatogenesis in mice

Maternal inheritance of mitochondrial DNA (mtDNA) is a widespread phenomenon in eukaryotes. Our earlier research indicated that sperm mtDNA is removed prior to fertilization in mice, and Endonuclease G (ENDOG) orchestrates the degradation of sperm mitochondria in Caenorhabditis elegans. However, the mechanisms underlying sperm mtDNA disposal in mammals remain poorly understood. To investigate the potential role of ENDOG in sperm mtDNA elimination, we created Endog knockout (Endog-/-) mice. Our findings revealed that Endog-/- mice maintained normal spermatogenesis and fertility. Most strikingly, we detected no substantial discrepancy in sperm mtDNA copy number between Endog-/- and control mice. Furthermore, we noted that sperm mtDNA copy numbers were unchanged in both less motile and motile sperm isolated by Percoll gradient centrifugation from Endog-/- and control mice. Taken together, our results indicate that ENDOG is not essential for spermatogenesis or the elimination of sperm mtDNA in mice.

Chemotherapy's effects on autophagy in the treatment of Hodgkin's lymphoma: a scoping review

BACKGROUND

Classical Hodgkin Lymphomas (HL) are a unique malignant growth with an excellent initial prognosis. However, 10-30% of patients will still relapse after remission. One primary cellular function that has been the focus of tumor progression is autophagy. This process can preserve cellular homeostasis under stressful conditions. Several studies have shown that autophagy may play a role in developing HL. Therefore, this review aimed to explore chemotherapy's effect on autophagy in HL, and the effects of autophagy on HL.

METHODS

A scoping review in line with the published PRISMA extension for scoping reviews (PRISMA-ScR) was conducted. A literature search was conducted on the MEDLINE database and the Cochrane Central Register of Controlled Trials (CENTRAL). All results were retrieved and screened, and the resulting articles were synthesized narratively.

RESULTS

The results showed that some cancer chemotherapy also induces autophagic flux. Although the data on HL is limited, since the mechanisms of action of these drugs are similar, we can infer a similar relationship. However, this increased autophagy activity may reflect a mechanism for increasing tumor growth or a cellular compensation to inhibit its growth. Although evidence supports both views, we argued that autophagy allowed cancer cells to resist cell death, mainly due to DNA damage caused by cytotoxic drugs.

CONCLUSION

Autophagy reflects the cell's adaptation to survive and explains why chemotherapy generally induces autophagy functions. However, further research on autophagy inhibition is needed as it presents a viable treatment strategy, especially against drug-resistant populations that may arise from HL chemotherapy regimens.

Multiomics Analysis Reveals Leucine Deprivation Promotes Bile Acid Synthesis by Upregulating Hepatic CYP7A1 and Intestinal Turicibacter sanguinis in Mice

BACKGROUND

Leucine, a branched-chain amino acid, participates in the regulation of lipid metabolism and the composition of the intestinal microbiota. However, the related mechanism remains unclear.

OBJECTIVES

Here, we aimed to reveal the potential mechanisms by which hepatic CYP7A1 (a rate-limiting enzyme for bile acid [BA] synthesis) and gut microbiota coregulate BA synthesis under leucine deprivation.

METHODS

To this end, 8-wk-old C57BL/6J mice were fed with either regular diets or leucine-free diets for 1 wk. Then, we investigated whether secondary BAs were synthesized by Turicibacter sanguinis in 7-wk-old C57BL/6J germ-free mice gavaged with T. sanguinis for 2 wk by determining BA concentrations in the plasma, liver, and cecum contents using liquid chromatography-tandem mass spectrometry.

RESULTS

The results showed that leucine deprivation resulted in a significant increase in total BA concentration in the plasma and an increase in the liver, but no difference in total BA was observed in the cecum contents before and after leucine deprivation. Furthermore, leucine deprivation significantly altered BA profiles such as taurocholic acid and ω-muricholic acid in the plasma, liver, and cecum contents. CYP7A1 expression was significantly upregulated in the liver under leucine deprivation. Leucine deprivation also regulated the composition of the gut microbiota; specifically, it significantly upregulated the relative abundance of T. sanguinis, thus enhancing the conversion of primary BAs into secondary BAs by intestinal T. sanguinis in mice.

CONCLUSIONS

Overall, leucine deprivation regulated BA profiles in enterohepatic circulation by upregulating hepatic CYP7A1 expression and increasing intestinal T. sanguinis abundance. Our findings reveal the contribution of gut microbiota to BA metabolism under dietary leucine deprivation.

Mitochondrial DNA release and sensing in innate immune responses

Mitochondria are pleiotropic organelles central to an array of cellular pathways including metabolism, signal transduction, and programmed cell death. Mitochondria are also key drivers of mammalian immune responses, functioning as scaffolds for innate immune signaling, governing metabolic switches required for immune cell activation, and releasing agonists that promote inflammation. Mitochondrial DNA (mtDNA) is a potent immunostimulatory agonist, triggering pro-inflammatory and type I interferon responses in a host of mammalian cell types. Here we review recent advances in how mtDNA is detected by nucleic acid sensors of the innate immune system upon release into the cytoplasm and extracellular space. We also discuss how the interplay between mtDNA release and sensing impacts cellular innate immune endpoints relevant to health and disease.

Aging-Related Rotator Cuff Tears: Molecular Mechanisms and Implications for Clinical Management

Shoulder pain and disabilities are prevalent issues among the elderly population, with rotator cuff tear (RCT) being one of the leading causes. Although surgical treatment has shown some success, high postoperative retear rates remain a great challenge, particularly in elderly patients. Aging-related degeneration of muscle, tendon, tendon-to-bone enthesis, and bone plays a critical role in the development and prognosis of RCT. Studies have demonstrated that aging worsens muscle atrophy and fatty infiltration, alters tendon structure and biomechanical properties, exacerbates enthesis degeneration, and reduces bone density. Although recent researches have contributed to understanding the pathophysiological mechanisms of aging-related RCT, a comprehensive systematic review of this topic is still lacking. Therefore, this article aims to present a review of the pathophysiological changes and their clinical significance, as well as the molecular mechanisms underlying aging-related RCT, with the goal of shedding light on new therapeutic approaches to reduce the occurrence of aging-related RCT and improve postoperative prognosis in elderly patients.

ALKBH1 promotes HIF-1α-mediated glycolysis by inhibiting N-glycosylation of LAMP2A

ALKBH1 is a typical demethylase of nucleic acids, which is correlated with multiple types of biological processes and human diseases. Recent studies are focused on the demethylation of ALKBH1, but little is known about its non-demethylase function. Here, we demonstrate that ALKBH1 regulates the glycolysis process through HIF-1α signaling in a demethylase-independent manner. We observed that depletion of ALKBH1 inhibits glycolysis flux and extracellular acidification, which is attributable to reduced HIF-1α protein levels, and it can be rescued by reintroducing HIF-1α. Mechanistically, ALKBH1 knockdown enhances chaperone-mediated autophagy (CMA)-mediated HIF-1α degradation by facilitating the interaction between HIF-1α and LAMP2A. Furthermore, we identify that ALKBH1 competitively binds to the OST48, resulting in compromised structural integrity of oligosaccharyltransferase (OST) complex and subsequent defective N-glycosylation of LAMPs, particularly LAMP2A. Abnormal glycosylation of LAMP2A disrupts lysosomal homeostasis and hinders the efficient degradation of HIF-1α through CMA. Moreover, NGI-1, a small-molecule inhibitor that selectively targets the OST complex, could inhibit the glycosylation of LAMPs caused by ALKBH1 silencing, leading to impaired CMA activity and disruption of lysosomal homeostasis. In conclusion, we have revealed a non-demethylation role of ALKBH1 in regulating N-glycosylation of LAMPs by interacting with OST subunits and CMA-mediated degradation of HIF-1α.

Functional Upgrading of an Organo-Ir(III) Complex to an Organo-Ir(III) Prodrug as a DNA Damage-Responsive Autophagic Inducer for Hypoxic Lung Cancer Therapy

The efficiency of nitrogen mustards (NMs), among the first chemotherapeutic agents against cancer, is limited by their monotonous mechanism of action (MoA). And tumor hypoxia is a significant obstacle in the attenuation of the chemotherapeutic efficacy. To repurpose the drug and combat hypoxia, herein, we constructed an organo-Ir(III) prodrug, IrCpNM, with the composition of a reactive oxygen species (ROS)-inducing moiety (Ir-arene fragment)-a hypoxic responsive moiety (azo linker)-a DNA-alkylating moiety (nitrogen mustard), and realized DNA damage response (DDR)-mediated autophagy for hypoxic lung cancer therapy for the first time. Prodrug IrCpNM could upregulate the level of catalase (CAT) to catalyze the decomposition of excessive H2O2 to O2 and downregulate the expression of the hypoxia-inducible factor (HIF-1α) to relieve hypoxia. Subsequently, IrCpNM initiates the quadruple synergetic actions under hypoxia, as simultaneous ROS promotion and glutathione (GSH) depletion to enhance the redox disbalance and severe oxidative and cross-linking DNA damages to trigger the occurrence of DDR-mediated autophagy via the ATM/Chk2 cascade and the PIK3CA/PI3K-AKT1-mTOR-RPS6KB1 signaling pathway. In vitro and in vivo experiments have confirmed the greatly antiproliferative capacity of IrCpNM against the hypoxic solid tumor. This work demonstrated the effectiveness of the DNA damage-responsive organometallic prodrug strategy with the microenvironment targeting system and the rebirth of traditional chemotherapeutic agents with a new anticancer mechanism.

Studying Antifatigue Mechanism of Tyr-Pro-Leu-Pro in Exercise Mice Using Label-Free Proteomics

In our previous study, yeast-derived peptide Tyr-Pro-Leu-Pro (YPLP) was found to prolong treadmill time and relieve muscle fatigue in ICR mice. The present study aimed to further investigate the antifatigue mechanism of YPLP. Three doses of YPLP (10, 25, and 50 mg/kg·d) were given to exercise mice for 4 weeks. Results showed that YPLP reduced the oxidative response via the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway and promoted energy metabolism through the AMP-activated protein kinase (AMPK) pathway. Label-free proteomics results showed that 81 differential abundance proteins (DAPs) were regulated by high-dose YPLP. These DAPs belonged to proteasome, mitochondrial, and muscle proteins. YPLP was mainly involved in proteasome, aminoacyl-tRNA biosynthesis, focal adhesion, and MAPK signal pathways to enhance muscle endurance. Furthermore, real-time quantitative PCR and Western blotting results proved that YPLP upregulated Psmd14 expression and downregulated p38 MAPK expression. Overall, this study revealed the mechanism behind YPLP to alleviate exercise fatigue.

TET3 is a positive regulator of mitochondrial respiration in Neuro2A cells

Ten-Eleven-Translocase (TET) enzymes contribute to the regulation of the methylome via successive oxidation of 5-methyl cytosine (5mC) to derivatives which can be actively removed by base-excision-repair (BER) mechanisms in the absence of cell division. This is particularly important in post-mitotic neurons where changes in DNA methylation are known to associate with changes in neural function. TET3, specifically, is a critical regulator of both neuronal differentiation in development and mediates dynamic changes in the methylome of adult neurons associated with cognitive function. While DNA methylation is understood to regulate transcription, little is known of the specific targets of TET3-dependent catalytic activity in neurons. We report the results of an unbiased transcriptome analysis of the neuroblastoma-derived cell line; Neuro2A, in which Tet3 was silenced. Oxidative phosphorylation (OxPhos) was identified as the most significantly down-regulated functional canonical pathway, and these findings were confirmed by measurements of oxygen consumption rate in the Seahorse bioenergetics analyser. The mRNA levels of both nuclear- and mitochondrial-encoded OxPhos genes were reduced by Tet3-silencing, but we found no evidence for differential (hydroxy)methylation deposition at these gene loci. However, the mRNA expression of genes known to be involved in mitochondrial quality control were also shown to be significantly downregulated in the absence of TET3. One of these genes; EndoG, was identified as a direct target of TET3-catalytic activity at non-CpG methylated sites within its gene body. Accordingly, we propose that aberrant mitochondrial homeostasis may contribute to the decrease in OxPhos, observed upon Tet3-downregulation in Neuro2A cells.

Myricetin, a natural inhibitor of CD147, increases sensitivity of cisplatin in ovarian cancer

BACKGROUND

Ovarian cancer (OC) is the most lethal gynecological tumor, but it currently lacks effective therapeutic targets. CD147, which is overexpressed in OC, plays a crucial role in promoting malignant progression and is associated with poor prognosis in patients. Therefore, CD147 has been identified as a potential therapeutic target. However, there is a limited amount of research on the development of CD147 inhibitors.

METHODS

Surface plasmon resonance (SPR) assay and virtual molecular docking analysis were performed to identify potential natural compounds targeting CD147. The anti‑tumor effects of myricetin were evaluated using various assays, including CCK8, Alkaline comet, immunofluorescence and xenograft mouse models. The underlying mechanism was investigated through western blot analysis and lentivirus short hairpin RNA (LV-shRNA) transfection.

RESULTS

Myricetin, a flavonoid commonly found in plants, was discovered to be a potent inhibitor of CD147. Our findings demonstrated that myricetin exhibited a strong affinity for CD147 and down-regulated the protein level of CD147 by facilitating its proteasome-dependent degradation. Additionally, we observed synergistic antitumor effects of myricetin and cisplatin both in vivo and in vitro. Mechanistically, myricetin suppressed the expression of FOXM1 and its downstream DNA damage response (DDR) genes E×O1and BRIP1, thereby enhancing the DDR induced by cisplatin.

CONCLUSION

Our data demonstrate that myricetin, a natural inhibitor of CD147, may have clinical utility in the treatment of OC due to its ability to increase genomic toxicity when combined with cisplatin.

YWHAG Deficiency Disrupts the EMT-Associated Network to Induce Oxidative Cell Death and Prevent Metastasis

Metastasis involves epithelial-to-mesenchymal transition (EMT), a process that is regulated by complex gene networks, where their deliberate disruption may yield a promising outcome. However, little is known about mechanisms that coordinate these metastasis-associated networks. To address this gap, hub genes with broad engagement across various human cancers by analyzing the transcriptomes of different cancer cell types undergoing EMT are identified. The oncogenic signaling adaptor protein tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG) is ranked top for its clinical relevance and impact. The cellular kinome and transcriptome data are surveyed to construct the regulome of YWHAG, revealing stress responses and metabolic processes during cancer EMT. It is demonstrated that a YWHAG-dependent cytoprotective mechanism in the regulome is embedded in EMT-associated networks to protect cancer cells from oxidative catastrophe through enhanced autophagy during EMT. YWHAG deficiency results in a rapid accumulation of reactive oxygen species (ROS), delayed EMT, and cell death. Tumor allografts show that metastasis potential and overall survival time are correlated with the YWHAG expression level of cancer cell lines. Metastasized tumors have higher expression of YWHAG and autophagy-related genes than primary tumors. Silencing YWHAG diminishes primary tumor volumes, prevents metastasis, and prolongs the median survival period of the mice.

Cytoplasmic Endonuclease G promotes nonalcoholic fatty liver disease via mTORC2-AKT-ACLY and endoplasmic reticulum stress

Endonuclease G (ENDOG), a nuclear-encoded mitochondrial intermembrane space protein, is well known to be translocated into the nucleus during apoptosis. Recent studies have shown that ENDOG might enter the mitochondrial matrix to regulate mitochondrial genome cleavage and replication. However, little is known about the role of ENDOG in the cytosol. Our previous work showed that cytoplasmic ENDOG competitively binds with 14-3-3γ, which released TSC2 to repress mTORC1 signaling and induce autophagy. Here, we demonstrate that cytoplasmic ENDOG could also release Rictor from 14-3-3γ to activate the mTORC2-AKT-ACLY axis, resulting in acetyl-CoA production. Importantly, we observe that ENDOG could translocate to the ER, bind with Bip, and release IRE1a/PERK to activate the endoplasmic reticulum stress response, promoting lipid synthesis. Taken together, we demonstrate that loss of ENDOG suppresses acetyl-CoA production and lipid synthesis, along with reducing endoplasmic reticulum stress, which eventually alleviates high-fat diet-induced nonalcoholic fatty liver disease in female mice.

Integrated transcriptomic and metabolomic analysis reveals the response of pearl oyster (Pinctada fucata martensii) to long-term hypoxia

The frequency at which organisms are exposed to hypoxic conditions in aquatic environments is increasing due to coastal eutrophication and global warming. To reveal the effects of long-term hypoxic stress on metabolic changes of pearl oyster, commonly known as Pinctada (Pinctada fucata martensii), the present study performed the integrated analysis of transcriptomics and metabolomics to investigate the global changes of genes and metabolites following 25 days hypoxia challenge. Transcriptome analysis detected 1108 differentially expressed genes (DEGs) between the control group and the hypoxia group. The gene ontology (GO) analysis of DEGs revealed that they are significantly enriched in functions such as "microtubule-based process", "histone (H3-K4, H3-K27, and H4-K20) trimethylation", "histone H4 acetylation", "kinesin complex", and "ATPase activity", and KEGG pathway functions, such as "DNA replication", "Apoptosis", and "MAPK signaling pathways". Metabolome analysis identified 68 significantly different metabolites from all identified metabolites, and associated with 25 metabolic pathways between the control and hypoxia groups. These pathways included aminoacyl-tRNA biosynthesis, arginine and proline metabolism, and phenylalanine metabolism. Our integrated analysis suggested that pearl oysters were subject to oxidative stress, apoptosis, immune inhibition, and neuronal excitability reduction under long-term hypoxic conditions. We also found a remarkable depression in a variety of biological functions under long-term hypoxia, including metabolic rates, biomineralization activities, and the repression of reorganization of the cytoskeleton and cell metabolism. These findings provide a basis for elucidating the mechanisms used by marine bivalves to cope with long-term hypoxic stress.

Single-Nucleotide Polymorphisms in Genes Maintaining the Stability of Mitochondrial DNA Affect the Occurrence, Onset, Severity and Treatment of Major Depressive Disorder

One of the key features of major depressive disorder (MDD, depression) is increased oxidative stress manifested by elevated levels of mtROS, a hallmark of mitochondrial dysfunction, which can arise from mitochondrial DNA (mtDNA) damage. Thus, the current study explores possibility that the single-nucleotide polymorphisms (SNPs) of genes encoding the three enzymes that are thought to be implicated in the replication, repair or degradation of mtDNA, i.e., POLG, ENDOG and EXOG, have an impact on the occurrence, onset, severity and treatment of MDD. Five SNPs were selected: EXOG c.-188T > G (rs9838614), EXOG c.*627G > A (rs1065800), POLG c.-1370T > A (rs1054875), ENDOG c.-394T > C (rs2977998) and ENDOG c.-220C > T (rs2997922), while genotyping was performed on 538 DNA samples (277 cases and 261 controls) using TaqMan probes. All SNPs of EXOG and ENDOG modulated the risk of depression, but the strongest effect was observed for rs1065800, while rs9838614 and rs2977998 indicate that they might influence the severity of symptoms, and, to a lesser extent, treatment effectiveness. Although the SNP located in POLG did not affect occurrence of the disease, the result suggests that it may influence the onset and treatment outcome. These findings further support the hypothesis that mtDNA damage and impairment in its metabolism play a crucial role not only in the development, but also in the treatment of depression.

Mitochondrial Factors in the Cell Nucleus

The origin of eukaryotic organisms involved the integration of mitochondria into the ancestor cell, with a massive gene transfer from the original proteobacterium to the host nucleus. Thus, mitochondrial performance relies on a mosaic of nuclear gene products from a variety of genomes. The concerted regulation of their synthesis is necessary for metabolic housekeeping and stress response. This governance involves crosstalk between mitochondrial, cytoplasmic, and nuclear factors. While anterograde and retrograde regulation preserve mitochondrial homeostasis, the mitochondria can modulate a wide set of nuclear genes in response to an extensive variety of conditions, whose response mechanisms often merge. In this review, we summarise how mitochondrial metabolites and proteins-encoded either in the nucleus or in the organelle-target the cell nucleus and exert different actions modulating gene expression and the chromatin state, or even causing DNA fragmentation in response to common stress conditions, such as hypoxia, oxidative stress, unfolded protein stress, and DNA damage.

eIF3f Mediates SGOC Pathway Reprogramming by Enhancing Deubiquitinating Activity in Colorectal Cancer

Numerous studies have demonstrated that individual proteins can moonlight. Eukaryotic Initiation translation factor 3, f subunit (eIF3f) is involved in critical biological functions; however, its role independent of protein translation in regulating colorectal cancer (CRC) is not characterized. Here, it is demonstrated that eIF3f is upregulated in CRC tumor tissues and that both Wnt and EGF signaling pathways are participating in eIF3f's oncogenic impact on targeting phosphoglycerate dehydrogenase (PHGDH) during CRC development. Mechanistically, EGF blocks FBXW7β-mediated PHGDH ubiquitination through GSK3β deactivation, and eIF3f antagonizes FBXW7β-mediated PHGDH ubiquitination through its deubiquitinating activity. Additionally, Wnt signals transcriptionally activate the expression of eIF3f, which also exerts its deubiquitinating activity toward MYC, thereby increasing MYC-mediated PHGDH transcription. Thereby, both impacts allow eIF3f to elevate the expression of PHGDH, enhancing Serine-Glycine-One-Carbon (SGOC) signaling pathway to facilitate CRC development. In summary, the study uncovers the intrinsic role and underlying molecular mechanism of eIF3f in SGOC signaling, providing novel insight into the strategies to target eIF3f-PHGDH axis in CRC.

SIRT6 regulates obesity-induced oxidative stress via ENDOG/SOD2 signaling in the heart

The sirtuin 6 (SIRT6) participates in regulating glucose and lipid homeostasis. However, the function of SIRT6 in the process of cardiac pathogenesis caused by obesity-associated lipotoxicity remains to be unveiled. This study was designed to elucidate the role of SIRT6 in the pathogenesis of cardiac injury due to nutrition overload-induced obesity and explore the downstream signaling pathways affecting oxidative stress in the heart. In this study, we used Sirt6 cardiac-specific knockout murine models treated with a high-fat diet (HFD) feeding to explore the function and mechanism of SIRT6 in the heart tissue during HFD-induced obesity. We also took advantage of neonatal cardiomyocytes to study the role and downstream molecules of SIRT6 during HFD-induced injury in vitro, in which intracellular oxidative stress and mitochondrial content were assessed. We observed that during HFD-induced obesity, Sirt6 loss-of-function aggravated cardiac injury including left ventricular hypertrophy and lipid accumulation. Our results evidenced that upon increased fatty acid uptake, SIRT6 positively regulated the expression of endonuclease G (ENDOG), which is a mitochondrial-resident molecule that plays an important role in mitochondrial biogenesis and redox homeostasis. Our results also showed that SIRT6 positively regulated superoxide dismutase 2 (SOD2) expression post-transcriptionally via ENDOG. Our study gives a new sight into SIRT6 beneficial role in mitochondrial biogenesis of cardiomyocytes. Our data also show that SIRT6 is required to reduce intracellular oxidative stress in the heart triggered by high-fat diet-induced obesity, involving the control of ENDOG/SOD2.

Caenorhabditis elegans for research on cancer hallmarks

After decades of research, our knowledge of the complexity of cancer mechanisms, elegantly summarized as 'hallmarks of cancer', is expanding, as are the therapeutic opportunities that this knowledge brings. However, cancer still needs intense research to diminish its tremendous impact. In this context, the use of simple model organisms such as Caenorhabditis elegans, in which the genetics of the apoptotic pathway was discovered, can facilitate the investigation of several cancer hallmarks. Amenable for genetic and drug screens, convenient for fast and efficient genome editing, and aligned with the 3Rs ('Replacement, Reduction and Refinement') principles for ethical animal research, C. elegans plays a significant role in unravelling the intricate network of cancer mechanisms and presents a promising option in clinical diagnosis and drug discovery.

Apoptotic proteins with non-apoptotic activity: expression and function in cancer

Apoptosis is a process of programmed cell death in which a cell commits suicide while maintaining the integrity and architecture of the tissue as a whole. Apoptosis involves activation of one of two major pathways: the extrinsic pathway, where extracellular pro-apoptotic signals, transduced through plasma membrane death receptors, activate a caspase cascade leading to apoptosis. The second, the intrinsic apoptotic pathway, where damaged DNA, oxidative stress, or chemicals, induce the release of pro-apoptotic proteins from the mitochondria, leading to the activation of caspase-dependent and independent apoptosis. However, it has recently become apparent that proteins involved in apoptosis also exhibit non-cell death-related physiological functions that are related to the cell cycle, differentiation, metabolism, inflammation or immunity. Such non-conventional activities were predominantly reported in non-cancer cells although, recently, such a dual function for pro-apoptotic proteins has also been reported in cancers where they are overexpressed. Interestingly, some apoptotic proteins translocate to the nucleus in order to perform a non-apoptotic function. In this review, we summarize the unconventional roles of the apoptotic proteins from a functional perspective, while focusing on two mitochondrial proteins: VDAC1 and SMAC/Diablo. Despite having pro-apoptotic functions, these proteins are overexpressed in cancers and this apparent paradox and the associated pathophysiological implications will be discussed. We will also present possible mechanisms underlying the switch from apoptotic to non-apoptotic activities although a deeper investigation into the process awaits further study.

Circ-calm4 regulates hypoxia-induced pulmonary artery smooth muscle autophagy by binding Purb

Pulmonary hypertension (PH) is a serious and fatal disease characterized by pulmonary vasoconstriction and pulmonary vascular remodeling. The excessive autophagy of pulmonary artery smooth muscle cells (PASMCs) is one of the important factors of pulmonary vascular remodeling. A number of studies have shown that circular RNA (circRNA) can participate in the onset of PH. Our previous studies have shown that circRNA calmodulin 4 (circ-calm4) is involved in the progression of hypoxic PH. However, the role of circ-calm4 on regulation of hypoxic PH autophagy has not been reported. In this study, we demonstrated for the first time that hypoxia-mediated upregulated circ-calm4 expression has a key regulatory effect on autophagy in hypoxia-induced PASMCs and hypoxic PH mouse models. Knockdown of circ-calm4 both in vivo and in vitro can inhibit the autophagy in PASMCs induced by hypoxia. We also performed bioinformatics predictions and conducted experiments to verify that circ-calm4 bound to the purine-rich binding protein (Purb) to promote its expression in the nucleus, thereby initiating the transcription of autophagy-related protein Beclin1. Interestingly, we found that Beclin1 transcription initiated by Purb was accompanied by a modification of Beclin1 super-enhancer to improve transcription activity and efficiency. Overall, our results confirm that the circ-calm4/Purb/Beclin1 signal axis is involved in the occurrence of hypoxia-induced PASMCs autophagy, and the novel regulatory mechanisms and signals transduction pathways in PASMC autophagy induced by hypoxia.

Self-Assembly Mitochondria-Targeting Donor-Acceptor Type Theranostic Nanosphere Activates ROS Storm for Multimodal Cancer Therapy

The rational design of cancer theranostics with natural diagnostic information and therapeutic behavior has been considered to be a big challenge, since common theranostics from photothermal and photodynamic therapy need to be activated with external stimuli of photoirradiation to enable the chemotherapeutic effects. In this contribution, we have designed and synthesized a series of simple theranostic agents, TPA-N-n (n = 4, 8, 12), which could accumulate at the tumor site over 48 h and indicate superior antiproliferative performance in vivo. TPA-N-n was constructed with electron donor triphenylamine-acceptor benzothiadiazole-mitochondria-targeting moiety pyridinium. Complex TPA-N-8 indicated the best cytotoxicity to cancerous HeLa cells, with an IC₅₀ value of 4.3 μM, and could self-assemble to a nanosphere with a size of 161.2 nm in the DMSO/PBS solution. It is worth noting that TPA-N-8 could accumulate in the mitochondria and produce major ROS species O₂•^- and OH• as well as small amounts of ¹O₂ without photoirradiation. Oxidative DNA damage is initiated due to the imbalance of intracellular redox homeostasis from the significant ROS storm. Multimodal synergistic therapy for HeLa cells was activated, as the PINK1-mediated mitophagy from the damaged mitochondria and DNA damage responsive (DDR) induced necroptosis and autophagy. This work not only provided a successful D-A type theranostic agent with superior anticancer performance from multimodal synergistic therapy but also further demonstrated the high efficacy of a mitochondria-targeting strategy for cancer treatment.

ATX-LPA-Dependent Nuclear Translocation of Endonuclease G in Respiratory Epithelial Cells: A New Mode Action for DNA Damage Induced by Crystalline Silica Particles

Crystalline silica particles (CSi) are an established human carcinogen, but it is not clear how these particles cause necessary mutations. A well-established scenario includes inflammation caused by retained particles in the bronchioles, activated macrophages, and reactive oxygen species (ROS) that cause DNA damage. In previous studies, we showed that CSi in contact with the plasma membrane of human bronchial epithelium induced double strand breaks within minutes. A signaling pathway implicating the ATX-LPA axis, Rac1, NLRP3, and mitochondrial depolarization upstream of DSB formation was delineated. In this paper, we provide in vitro and in vivo evidence that this signaling pathway triggers endonuclease G (EndoG) translocation from the mitochondria to the nucleus. The DNA damage is documented as γH2AX and p53BP1 nuclear foci, strand breaks in the Comet assay, and as micronuclei. In addition, the DNA damage is induced by low doses of CSi that do not induce apoptosis. By inhibiting the ATX-LPA axis or by EndoG knockdown, we prevent EndoG translocation and DSB formation. Our data indicate that CSi in low doses induces DSBs by sub-apoptotic activation of EndoG, adding CSi to a list of carcinogens that may induce mutations via sub-apoptotic and "minority MOMP" effects. This is the first report linking the ATX-LPA axis to this type of carcinogenic effect.

The cyclic guanosine monophosphate synthase-stimulator of interferon genes pathway as a potential target for tumor immunotherapy

Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) detects infections or tissue damage by binding to microbial or self-DNA in the cytoplasm. Upon binding DNA, cGAS produces cGAMP that binds to and activates the adaptor protein stimulator of interferon genes (STING), which then activates the kinases IKK and TBK1 to induce the secretion of interferons and other cytokines. Recently, a series of studies demonstrated that the cGAS-STING pathway, a vital component of host innate immunity, might play an important role in anticancer immunity, though its mechanism remains to be elucidated. In this review, we highlight the latest understanding of the cGAS-STING pathway in tumor development and the advances in combination therapy of STING agonists and immunotherapy.

The Importance of mTORC1-Autophagy Axis for Skeletal Muscle Diseases

The mechanistic target of rapamycin (mTOR) complex 1, mTORC1, integrates nutrient and growth factor signals with cellular responses and plays critical roles in regulating cell growth, proliferation, and lifespan. mTORC1 signaling has been reported as a central regulator of autophagy by modulating almost all aspects of the autophagic process, including initiation, expansion, and termination. An increasing number of studies suggest that mTORC1 and autophagy are critical for the physiological function of skeletal muscle and are involved in diverse muscle diseases. Here, we review recent insights into the essential roles of mTORC1 and autophagy in skeletal muscles and their implications in human muscle diseases. Multiple inhibitors targeting mTORC1 or autophagy have already been clinically approved, while others are under development. These chemical modulators that target the mTORC1/autophagy pathways represent promising potentials to cure muscle diseases.

The regulatory roles of circular RNAs via autophagy in ischemic stroke

Ischemic stroke (IS) is a severe disease with a high disability, recurrence, and mortality rates. Autophagy, a highly conserved process that degrades damaged or aging organelles and excess cellular components to maintain homeostasis, is activated during IS. It influences the blood–brain barrier integrity and regulates apoptosis. Circular RNAs (circRNAs) are novel non-coding RNAs involved in IS-induced autophagy and participate in various pathological processes following IS. In addition, they play a role in autophagy regulation. This review summarizes current evidence on the roles of autophagy and circRNA in IS and the potential mechanisms by which circRNAs regulate autophagy to influence IS injury. This review serves as a basis for the clinical application of circRNAs as novel biomarkers and therapeutic targets in the future.

Autophagy deficiency abolishes liver mitochondrial DNA segregation

Mutations in the mitochondrial genome (mtDNA) are ubiquitous in humans and can lead to a broad spectrum of disorders. However, due to the presence of multiple mtDNA molecules in the cell, co-existence of mutant and wild-type mtDNAs (termed heteroplasmy) can mask disease phenotype unless a threshold of mutant molecules is reached. Importantly, the mutant mtDNA level can change across lifespan as mtDNA segregates in an allele- and cell-specific fashion, potentially leading to disease. Segregation of mtDNA is mainly evident in hepatic cells, resulting in an age-dependent increase of mtDNA variants, including non-synonymous potentially deleterious mutations. Here we modeled mtDNA segregation using a well-established heteroplasmic mouse line with mtDNA of NZB/BINJ and C57BL/6N origin on a C57BL/6N nuclear background. This mouse line showed a pronounced age-dependent NZB mtDNA accumulation in the liver, thus leading to enhanced respiration capacity per mtDNA molecule. Remarkably, liver-specific atg7 (autophagy related 7) knockout abolished NZB mtDNA accumulat ion, resulting in close-to-neutral mtDNA segregation through development into adulthood. prkn (parkin RBR E3 ubiquitin protein ligase) knockout also partially prevented NZB mtDNA accumulation in the liver, but to a lesser extent. Hence, we propose that age-related liver mtDNA segregation is a consequence of macroautophagic clearance of the less-fit mtDNA. Considering that NZB/BINJ and C57BL/6N mtDNAs have a level of divergence comparable to that between human Eurasian and African mtDNAs, these findings have potential implications for humans, including the safe use of mitochondrial replacement therapy.Abbreviations: Apob: apolipoprotein B; Atg1: autophagy-related 1; Atg7: autophagy related 7; Atp5a1: ATP synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1; BL6: C57BL/6N mouse strain; BNIP3: BCL2/adenovirus E1B interacting protein 3; FCCP: carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; MAP1LC3A: microtubule-associated protein 1 light chain 3 alpha; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; mt-Atp8: mitochondrially encoded ATP synthase 8; MT-CO1: mitochondrially encoded cytochrome c oxidase I; MT-CO2: mitochondrially encoded cytochrome c oxidase II; mt-Co3: mitochondrially encoded cytochrome c oxidase III; mt-Cytb: mitochondrially encoded cytochrome b; mtDNA: mitochondrial DNA; MUL1: mitochondrial ubiquitin ligase activator of NFKB 1; nDNA: nuclear DNA; Ndufa9: NADH:ubiquinone oxireductase subunit A9; NDUFB8: NADH:ubiquinone oxireductase subunit B8; Nnt: nicotinamide nucleotide transhydrogenase; NZB: NZB/BINJ mouse strain; OXPHOS: oxidative phosphorylation; PINK1: PTEN induced putative kinase 1; Polg2: polymerase (DNA directed), gamma 2, accessory subunit; Ppara: peroxisome proliferator activated receptor alpha; Ppia: peptidylprolyl isomerase A; Prkn: parkin RBR E3 ubiquitin protein ligase; P10: post-natal day 10; P21: post-natal day 21; P100: post-natal day 100; qPCR: quantitative polymerase chain reaction; Rpl19: ribosomal protein L19; Rps18: ribosomal protein S18; SD: standard deviation; SEM: standard error of the mean; SDHB: succinate dehydrogenase complex, subunit B, iron sulfur (Ip); SQSTM1: sequestosome 1; Ssbp1: single-stranded DNA binding protein 1; TFAM: transcription factor A, mitochondrial; Tfb1m: transcription factor B1, mitochondrial; Tfb2m: transcription factor B2, mitochondrial; TOMM20: translocase of outer mitochondrial membrane 20; UQCRC2: ubiquinol cytochrome c reductase core protein 2; WT: wild-type.

Comprehensive analysis of placental gene-expression profiles and identification of EGFR-mediated autophagy and ferroptosis suppression in intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) was the most common liver disease specific to pregnancy. The symptoms of ICP were maternal pruritus and increased bile acid level in serum which was related to preterm birth, fetal distress, meconium-stained amniotic fluid and stillbirth. However, the mechanism of ICP progression on fetal development remained obscure. Sequencing data of 2 normal placenta samples and 4 intrahepatic cholestasis samples during pregnancy was analyzed by GEO2R. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for analysis of differentially expressed genes. MCODE - A plug-in of Cytoscape was used for molecular complex detection. STRING, Cytoscape, GeneMANIA, NetworkAnalyst, TransmiR, JASPAR, DGIdb and DrugBank were used in this study. Furthermore, histopathological and cell experiments were used to verify our results. Our study identified the key KEGG pathway and four MCODEs which were closely with ICP development, further, sorted by degree centrality, we showed top 30 genes from 7209 differential genes, such as TP53, SRC, EGFR, ESR1, IL10, CD8A, MAPK3, PTPRC, EGF, KIT, ITGAM, LEP and CSF2, etc. Moreover, these hub genes participated in JAK-STAT3 signaling pathway and STAT1/3 regulated these genes expression in a direct way or miRNA-mediated manner. Drug-target analysis about up-regulated genes among hub genes showed that these genes contained multiple drug action site. Furthermore, hub gene-EGFR was associated with destroyed autophagy and ferroptosis. In conclusion, our study analyzed key genes and pathways in ICP development. JAK-STAT3 pathway and EGFR might be a potential target for ICP therapy.

Assessment of the Role of Nuclear ENDOG Gene and mtDNA Variations on Paternal Mitochondrial Elimination (PME) in Infertile Men: An Experimental Study

In humans and most animals, maternal inheritance of mitochondria and mitochondrial DNA (mtDNA) is considered as an universal assumption. Recently, several lines of evidence suggest that different species seem to employ distinct mechanisms to prevent the inheritance of paternal mtDNA. There are few studies in the literature on the molecular basis of sperm mtDNA elimination in mammals and paternal mtDNA transmission in humans. Endonuclease G (ENDOG) is a mitochondrial nuclease encoded by nuclear ENDOG gene. The critical importance of ENDOG gene on paternal mitochondrial elimination (PME) has been previously demonstrated in model organisms such as C. elegans and D. melanogaster. However, its mechanism in human is still unclear. Therefore, we aimed to evaluate whether nuclear ENDOG gene copy number could be a potential marker of paternal mtDNA transmission or not.Male factor infertility patients diagnosed with different infertility subgroups such as azoospermia, oligoteratozoospermia, astheno-teratozoospermia were included in this study: 13 infertile men and 25 healthy men as control group. Quantitative real-time polymerase chain reaction (qPCR) analysis and dual-color Fluorescence in situ hybridization (FISH) method were used to compare the groups. FISH method was applied to verify qPCR results and two signals were observed in nearly all patients. ENDOG gene copy number data were evaluated by comparing them with entire human mtDNA next-generation sequencing (NGS) analysis results obtained through bioinformatics and proteomics tools. Mitochondrial whole genome sequencing (WGS) data allowed determination of novel and reported variations such as single nucleotide polymorphisms (SNPs), multiple nucleotide polymorphism (MNP), insertion/deletion (INDEL). Missense variants causing amino acid substitution were filtered out from patients' mtDNA WGS data.Relative copy number of target ENDOG gene in male infertility patients [0.49 (0.31 - 0.77)] was lower than healthy controls [1.00 (0.66 - 1.51)], and statistical results showed significant differences between the groups (p < 0.01). A total of 38 missense variants were detected in the genes encoding the proteins involved in the respiratory chain complex. Moreover, we detected paternal mtDNA transmissions in the children of these patients who applied to assisted reproductive techniques.In conclusion, this study reveals that ENDOG gene may be an important factor for the PME mechanism in humans. To the best of our knowledge, this is the first study in humans about this topic and assessment of ENDOG gene sequencing and gene expression studies in a larger sample size including patients with male factor infertility would be our future project.

Chlorin e6-Induced Photodynamic Effect Polarizes the Macrophage Into an M1 Phenotype Through Oxidative DNA Damage and Activation of STING

The tumor-associated macrophage (TAM) serves as an immunosuppressive agent in the malignant tumor microenvironment, facilitating the development and metastasis of lung cancer. The photodynamic effect destabilizes cellular homeostasis owing to the generation of reactive oxygen species (ROS), resulting in the enhanced pro-inflammatory function of immunocytes. In our previous study, the Ce6-mediated photodynamic effect was found to have kept the viability of macrophages and to remodel them into the M1 phenotype. However, the mechanism remains unrevealed. The present study now explores the mechanism of photodynamic therapy (PDT)-mediated reprogramming of macrophages. As expected, Ce6-mediated PDT was capable of generating reactive oxygen species, which was continuously degraded, causing "low intensity" damage to DNA and thereby triggering subsequent DNA damage response in macrophages. The autophagy was thus observed in Ce6-treated macrophages and was shown to protect cells from being photodynamically apoptotic. More importantly, Ce6 PDT could activate the stimulator of interferon genes (STING) molecule, a sensor of DNA damage, which could activate the downstream nuclear factor kappa-B (NF-κB) upon activation, mediating the polarization of macrophages towards the M1 phenotype thereupon. In addition, inhibition of ROS induced by PDT attenuated the DNA damage, STING activation, and M1-phenotype reprogramming. Furthermore, the silence of the STING weakened Ce6 treatment-mediated M1 remodeling of macrophages as well. Altogether, these findings indicate the Ce6-induced photodynamic effect polarizes macrophages into an M1 phenotype through oxidative DNA damage and subsequent activation of the STING. This work reveals the crucial mechanism by which photodynamic therapy regulates the macrophage phenotype and also provides a novel intervenable signaling target for remodeling macrophages into the M1 phenotype.

Transcription and Post-translational Regulation of Autophagy in Insects

Autophagy attracts great attention, and numerous progresses have been obtained in the last two decades. Autophagy is implicated in mammalian neurodegenerative diseases, tumorigenesis, as well as development in insects. The regulatory mechanism of autophagy is well documented in yeast and mammals, whereas it is not fully illustrated in insects. Drosophila melanogaster and Bombyx mori are the two well-studied insects for autophagy, and several insect-mammalian evolutionarily conserved or insect-specific mechanisms in regulating autophagy are reported. In this review, we summarize the most recent studies of autophagy regulated at both transcriptional and post-translational levels by insect hormone in cooperation with other signals, such as nutrient, which will provide a reference and deep thinking for studies on autophagy in insects.

Insight into Analysis of Essential Oil from Anisosciadium lanatum Boiss.-Chemical Composition, Molecular Docking, and Mitigation of Hepg2 Cancer Cells through Apoptotic Markers

Essential oils have been used in various traditional healing systems since ancient times worldwide, due to their diverse biological activities. Several studies have demonstrated their plethora of biological activities-including anti-cancer activity-in a number of cell lines. Anisosciadium lanatum Boiss. is a perennial aromatic herb. Traditionally, it is an edible safe herb with few studies exploring its importance. The current study aims to investigate the chemical composition of essential oil isolated from Anisosciadium lanatum using GC-MS, as well as report its anti-cancer potential and its mechanistic effect on HepG2 liver cancer cell lines, and conduct molecular docking studies. To achieve this, the essential oil was isolated using a Clevenger apparatus and analyzed using GC-MS. The cell viability of HepG2 liver cancer and normal fibroblast NIH-3T3 cell lines was assessed by MTT cytotoxicity assay. The effects of the essential oil on cell migration and invasion were assessed using wound healing and matrigel assays, respectively. The effect of the essential oil on migration and apoptotic-regulating mRNA and proteins was quantified using quantitative real-time PCR and Western blot techniques, respectively. Finally, computational docking tools were used to analyze in silico binding of major constituents from the essential oil against apoptotic and migration markers. A total of 38 components were identified and quantified. The essential oil demonstrated regulation of cell proliferation and cell viability in HepG2 liver cancer cells at a sub-lethal dose of 10 to 25 μg/mL, and expressed reductions of migration and invasion. The treatment with essential oil indicated mitigation of cancer activity by aborting the mRNA of pro-apoptotic markers such as BCL-2, CASPASE-3, CYP-1A1, and NFκB. The algorithm-based binding studies demonstrated that eucalyptol, nerol, camphor, and linalool have potent binding towards the anti-apoptotic protein BCL-2. On the other hand, camphor and eucalyptol showed potent binding towards the pro-apoptotic protein CASPASE-3. These findings highlight the effectiveness of the essential oil isolated from Anisosciadium lanatum to drive alleviation of HepG2 cancer cell progression by modulating apoptotic markers. Our findings suggest that Anisosciadium lanatum could be used as a phytotherapeutic anti-cancer agent, acting through the regulation of apoptotic markers. More well-designed in vivo trials are needed in order to verify the obtained results.

Ubiquitinated Hepatitis D Antigen-Loaded Microvesicles Induce a Potent Specific Cellular Immune Response to Inhibit HDV Replication in Vivo

Hepatitis D is the most severe form of human viral hepatitis and currently lacks an efficient therapy. Dendritic cell-derived exosomes (Dexs) have been found to induce immune responses capable of eliminating viruses. However, the therapeutic potential of antigen-loaded exosomes in hepatitis D is still unknown. Recently, we designed exosomes loaded with ubiquitinated hepatitis delta virus (HDV) small delta antigen (Ub-S-HDAg) and then treated mice bearing replicating HDV with these exosomes to explore their antiviral effect and mechanism. Mature dendritic cell-derived exosomes (mDexs) were loaded with Ub-S-HDAg and their antivirus function was evaluated in mice with HDV viremia. Furthermore, the proportion of CD8⁺ cells, the ratio of Th1/Th2 cells, the postimmunization levels of cytokines were explored, and the Janus kinases (JAK)/signal transducer and activator of transcription (STAT) pathway was evaluated with a JAK2 inhibitor AG490. In Ub-S-HDAg-Dexs group, the HDV RNA viral load was significantly decreased compared with other groups by CD8⁺ cell enrichment and an increase Th1/Th2 cell ratio. Furthermore, lymphocyte infiltration was increased, while the HDAg level was decreased in mouse liver tissue. However, there were no significant differences in HBV surface antigen (HBsAg), alanine aminotransferase (ALT), or aspartate aminotransferase (AST) levels among the groups. Moreover, p-JAK2, p-STAT1, p-STAT4, STAT1, and STAT4 expression was increased in Ub-S-HDAg-Dexs group. In conclusion, Ub-S-HDAg-Dexs might be a potential immunotherapeutic agent for eradicating HDV by inducing specific cellular immune response via the JAK/STAT pathway. IMPORTANCE Hepatitis D is the most severe viral hepatitis with accelerating the process of liver cirrhosis and increasing the risk of hepatocellular carcinoma. However, there are no effective antiviral drugs. Exosomes derived from mature dendritic cells are used not only as immunomodulators, but also as biological carriers to deliver antigens to induce robust immune response. Based on these properties, exosomes could be used as a biological immunotherapy by enhancing adaptive immune response to inhibit hepatitis D virus replication. Our research may provide a new therapeutic strategy to eradicate HDV in the future.

Intestinal Macrophage Autophagy and its Pharmacological Application in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), comprised of Crohn’s disease (CD) and ulcerative colitis (UC), is a group of chronic inflammatory disorders. IBD is regarded as a severe healthcare problem worldwide, with high morbidity and lethality. So far, despite of numerous studies on this issue, the specific mechanisms of IBD still remain unclarified and ideal treatments are not available for IBD. The intestinal mucosal barrier is vital for maintaining the function of the intestinal self-defensive system. Among all of the components, macrophage is an important one in the intestinal self-defensive system, normally protecting the gut against exotic invasion. However, the over-activation of macrophages in pathological conditions leads to the overwhelming induction of intestinal inflammatory and immune reaction, thus damaging the intestinal functions. Autophagy is an important catabolic mechanism. It has been proven to participate the regulation of various kinds of inflammation- and immune-related disorders via the regulation of inflammation in related cells. Here in this paper, we will review the role and mechanism of intestinal macrophage autophagy in IBD. In addition, several well-studied kinds of agents taking advantage of intestinal macrophage autophagy for the treatment of IBD will also be discussed. We aim to bring novel insights in the development of therapeutic strategies against IBD.

Effect of Quercetin on Injury to Indomethacin-Treated Human Embryonic Kidney 293 Cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat inflammation and pain and even to prevent the progression of cardiovascular disease. They have become widely used because of their effectiveness, especially among athletes performing high-intensity training. Indomethacin is used for pain management in sports medicine and is highly effective and versatile. However, several clinical studies have reported that indomethacin induces acute renal damage. In the present study, we determined that indomethacin reduced human embryonic kidney 293 (HEK293) cell viability in a concentration-dependent manner by triggering apoptosis. In addition, we demonstrated the effect of quercetin on indomethacin-treated HEK293 cells by inactivating the caspase-3 and caspase-9 signals. Furthermore, quercetin reduced ROS production and increased mitochondrial membrane potential (ΔΨm) in indomethacin-treated HEK293 cells. Our results indicate that quercetin can interrupt the activated caspase and mitochondrial pathway induced by indomethacin in HEK293 cells and affect apoptotic mRNA expression. Quercetin can protect against indomethacin-induced HEK293 cell apoptosis by regulating abnormal ΔΨm and apoptotic mRNA expression.

Distinct mitochondria-mediated T cells apoptosis responses in children and adults with COVID-19

BACKGROUND

Lymphopenia is a key feature for adult patients with coronavirus disease 2019 (COVID-19), while it is rarely observed in children. The underlying mechanism remains unclear.

METHODS

Immunohistochemical and flow cytometric analyses were used to compare the apoptotic rate of T cells from COVID-19 adults and children and apoptotic responses of adult and child T cells to COVID-19 pooled plasma. Biological properties of caspases and reactive oxygen species were assessed in T cells treated by COVID-19 pooled plasma.

RESULTS

Mitochondria apoptosis of peripheral T cells were identified in COVID-19 adult patient samples, but not in the children. Furthermore, increased TNF-α and IL-6 in COVID-19 plasma induced mitochondria apoptosis and caused DNA damage by elevating reactive oxygen species levels of the adult T cells. However, the child T cells showed tolerance to mitochondrial apoptosis due to mitochondria autophagy. Activation of autophagy could decrease apoptotic sensitivity of the adult T cells to plasma from COVID-19 patients.

CONCLUSIONS

Our results indicated that the mitochondrial apoptosis pathway was activated in T cells of COVID-19 adult patients specifically, which may shed light on the pathophysiological difference between adults and children infected with SARS-CoV-2.

Characterization and Expression Analyses of Callose Synthase Enzyme (Cals) Family Genes in Maize (Zea mays L.)

The callose synthase enzyme genes (Cals) generally plays an important role in resisting to environmental stresses as well as in regulating the microspore development of higher plant. However till now, few researches about ZmCals genes have been reported in maize. In this study, ten ZmCals genes were identified, and they are distributed on four chromosomes in maize. All ZmCals proteins contain Glucan-synthase-domain and Fks1-domain. RNA-seq data from public databases were analyzed and the result suggested that ZmCals involved in the development of various tissues, and a strong expression presented especially in young tissue. qRT-PCR analysis shown that most of ZmCals are highly expressed in root, stem and leaf at jointing stage (V6 stage) with maize inbred line B73. Seven out of 10 ZmCals genes display higher expression during maize anther development especially from stage 6 to stage 8b, the dynamic accumulation process of callose is also observed during these period with aniline blue staining. Above results indicated multiple ZmCals may participate in the deposition of callose in maize anther. Therefore, ZmCals are necessary not only for reproductive organ but also for nutritive organ during maize growth and development. This study lays certain foundation for further investigating the roles of the callose synthase enzymes genes in maize.

Mutagenic Consequences of Sublethal Cell Death Signaling

Many human cancers exhibit defects in key DNA damage response elements that can render tumors insensitive to the cell death-promoting properties of DNA-damaging therapies. Using agents that directly induce apoptosis by targeting apoptotic components, rather than relying on DNA damage to indirectly stimulate apoptosis of cancer cells, may overcome classical blocks exploited by cancer cells to evade apoptotic cell death. However, there is increasing evidence that cells surviving sublethal exposure to classical apoptotic signaling may recover with newly acquired genomic changes which may have oncogenic potential, and so could theoretically spur the development of subsequent cancers in cured patients. Encouragingly, cells surviving sublethal necroptotic signaling did not acquire mutations, suggesting that necroptosis-inducing anti-cancer drugs may be less likely to trigger therapy-related cancers. We are yet to develop effective direct inducers of other cell death pathways, and as such, data regarding the consequences of cells surviving sublethal stimulation of those pathways are still emerging. This review details the currently known mutagenic consequences of cells surviving different cell death signaling pathways, with implications for potential oncogenic transformation. Understanding the mechanisms of mutagenesis associated (or not) with various cell death pathways will guide us in the development of future therapeutics to minimize therapy-related side effects associated with DNA damage.

Conserved role of ENDOG in promoting autophagy

ENDOG (endonuclease G), a mitochondrial endonuclease, is known to participate in apoptosis and paternal mitochondria elimination. However, the role and underlying mechanism of ENDOG in regulating macroautophagy remain unclear. We recently reported that ENDOG released from mitochondria promotes autophagy during starvation, which we demonstrated is evolutionarily conserved across species by performing experiments in human cell lines, mice, Drosophila, and C. elegans. This study demonstrates that ENDOG can be phosphorylated by GSK3B, which enhances the interaction between ENDOG with YWHAG and leads to the release of TSC2 and PIK3C3 from YWHAG, followed by MTOR pathway suppression and autophagy initiation. Additionally, the endonuclease activity of ENDOG is essential for activating the DNA damage response and thus inducing autophagy. Consequently, this study uncovered an exciting new role for ENDOG as a crucial regulator of autophagy.