mTOR in programmed cell death and its therapeutic implications

Substituents introduction of methyl and methoxy functional groups on resveratrol stabilizes mTOR binding for autophagic cell death induction

The regulation of the mammalian target of rapamycin (mTOR) protein by cancer cells can lead to uncontrol of cancer cell growth and cancer therapy resistance. The drug discovery of the anticancer agent 5-(3-hydroxy-4-methoxyphenethyl)-2-methoxy-3-methylphenol (SM-3), a derivative of resveratrol by substituting a methyl group at the hydroxy group of ring A and adding a methoxy group at the para position of ring B, shows promising potential for targeting autophagy to induce cell death and suppress cancer stem cells (CSCs) through the inhibition of the mTOR protein. In human lung cancer cells, SM-3 showed greater efficacy, with lower IC50 values of 72.74 ± 0.13, 67.66 ± 0.10, and 43.24 ± 0.11 µM in A549, H292, and H460 cells, respectively, compared to the parent compound, Resveratrol (Res). Moreover, the selectivity index (SI) values for BEAS2B cells compared to tumor cells treated with SM-3 were 10.99, 11.81, and 18.49 for A549, H292, and H460 cell lines, respectively. Therefore, SM-3 treatment led to reduced proliferation rates and colony formation in lung cancer cells. In our study, spheroids treated with SM-3 showed a higher proportion of dead spheroids compared to those treated with Res. Additionally, SM-3 treatment resulted in decreased expression of stem cell markers (CD133, CD44, and ALDH1A1) and transcription factors (OCT4, NANOG, and SOX2) in spheroids and organoids from human lung cancer cells by inhibiting the mTOR/pAkt pathway. SM-3 was also found to induce autophagic cell death, as indicated by Monodansylcadaverine staining, acidic vesicle formation, and the conversion of LC3BI to LC3BII. Using MM/GBSA calculations, SM-3 exhibited a stronger binding affinity (-25.09 kcal/mol) compared to Res (-18.85 kcal/mol). SM-3 also displayed greater stability during the entire simulation, maintaining lower RMSD values of 2-3 Å even after 80 ns. In summary, the introduction of methyl and methoxy functional groups on Res to create SM-3 effectively suppressed cancer spheroids and organoids formation in lung cancer cells by targeting the upstream mTOR/pAkt pathway.

Bromodomain and extraterminal protein inhibitor JQ1 induces maturation arrest and disrupts the cytoplasmic organization in mouse oocytes under in vitro conditions

JQ1, a small cell-permeable molecule is known for its potent inhibitory action on bromodomain and extraterminal (BET) proteins. Although earlier studies have shown its inhibitory effect on male gametogenesis, limited information is available about its influence on oocyte development. Since BET genes are known to exhibit regulatory functions on oocyte development and maturation, the present study aimed to investigate the effect of JQ1 on oocyte developmental competence under in vitro conditions. Germinal vesicle (GV) stage oocytes were collected from adult Swiss albino mice and subjected to in vitro maturation (IVM) in the presence of various concentrations of JQ1 (25, 50, and 100 μM). The metaphase II (MII) stage oocytes were assessed for cytoplasmic organization and functional competence at 24 h after IVM. A significant decrease in nuclear maturation (at 50 and 100 μM), symmetric cytokinesis, altered distribution of mitochondria and cortical granules, poorly organized actin and meiotic spindle, misaligned chromosomes, and elevated endoplasmic reticulum (ER) stress and oxidative stress was observed in JQ1-exposed oocytes. Presence of N-acetyl cysteine (NAC), in IVM medium resulted in significant reduction in JQ1-induced oxidative stress and symmetric cytokinesis. Administration of JQ1 (50 mg/kg, intra peritoneal) to adult Swiss albino mice primed with pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) did not affect the ovulation. However, a high degree of oocyte degeneration, elevated intracellular reactive oxygen species (ROS), and GRP78 expression was observed in JQ1-administered mice. In conclusion, our study reveals that BET inhibitor JQ1 has detrimental effects on oocyte function and development.

Radiation induced dermatitis by increasing triglyceride levels to induce autophagy and inhibit the PI3K/Akt/mTOR signaling pathway

BACKGROUND

Radiodermatitis (RD) is the primary acute adverse effect experienced by patients receiving radiotherapy (RT) for head and neck cancer (HNC). This study aimed to investigate the correlation between triglyceride (TG) levels and the severity of RD, as well as the underlying mechanisms involved.

METHODS

Data were collected from 248 patients with locally advanced HNC treated with intensity-modulated radiation therapy (IMRT). Clinical characteristics and blood profiles prior to RT were collected. After RT, RD severity was assessed. A binary logistic regression analysis was used to determine risk factors. Mouse models of RD were established by administering radiating at a dose of 9 Gy over two consecutive days. TG levels in the mice and cells were quantified using an automatic biochemical analyzer and a TG assay kit, respectively. Cell viability was detected by the Cell Counting Kit-8 (CCK-8) assay, while apoptotic cell percentages were measured via flow cytometry. Western blotting assay was used to analyze the protein levels in the cells of interest.

RESULTS

The TG level was the sole independent risk factor for grade 3 or higher (grade 3+) RD. Radiation was found to increase the TG content in both mouse blood and skin cells. Skin cells with high TG contents presented more severe radiation-induced damage when the radiation dose administered was 9 Gy over two consecutive days. The administration of 200 µmol/L palmitic acid (PA) or 2 Gy radiation independently did not affect HaCaT cell proliferation or apoptosis rates. Their combination was shown to induce skin cell injury. Mechanistically, autophagy was excessively activated. Furthermore, the protein concentrations of phospho-PI3K, phospho-Akt, and phospho-mTOR were notably decreased.

CONCLUSIONS

TGs are crucially involved in the development of RD. Increased TG levels after radiation treatment suppress the PI3K/Akt/mTOR pathway, induce autophagy, and exacerbate RD.

Upregulating mTOR/S6 K Pathway by CASTOR1 Promotes Astrocyte Proliferation and Myelination in Gpam-/--induced mouse model of cerebral palsy

GPAM, a key enzyme for lipid synthesis, is predominantly expressed in astrocytes (ASTs), where it facilitates lipid supply for myelin formation. Our previous studies identified GPAM as a novel causative gene for cerebral palsy (CP) and led to the development of a CP mouse model with GPAM deficiency (Gpam-/-). The model closely recapitulated the clinical phenotype of children with CP, due to the restricted proliferation of ASTs in the brain, reduced the amount of lipid, thinner brain white matter, and myelin dysplasia. The mammalian target of rapamycin (mTOR) pathway plays an important role in cell proliferation and lipid synthesis. Cytosolic arginine sensor (CASTOR1) interacts with GATOR2 to regulate mTOR complex 1 (mTORC1). Targeted degradation of CASTOR1 can activate the mTOR pathway. However, it remains unclear the involvement of mTOR pathway in neurological diseases such as CP. In this study, we demonstrated that the mTOR pathway was inhibited in Gpam-/- mice. Notably, CASTOR1 could regulate the activity of mTOR/S6K pathway, functioning as a negative upstream regulator. Furthermore, inhibition of CASTOR1 upregulated mTOR/S6K signaling, promoting astrocyte proliferation and myelination, which in turn enhanced motor function in the Gpam-/--induced CP mouse model. Collectively, these findings reveal the role of astrocytic mTOR in the pathogenesis of CP mice, broaden the therapeutic strategies, and provide a promising candidate target for CP treatment.

Heat Stress in Growing-Finishing Pigs: Effects of Low Protein with Increased Crystalline Amino Acids on Growth, Gut Health, Antioxidant Status and Microbiome

A total of sixty crossbred ([Landrace × Yorkshire] × Duroc) pigs with an initial body weight of 46.34 ± 0.13 kg were randomly assigned to four treatments under thermoneutral (TN, 22 °C) or heat-stress (HS, 31 °C) conditions for 54 d trial (Phase 1: 0-26 d; Phase 2: 27-54 d): a control diet (16% CP in phase 1, 14% CP in phase 2) under TN (PC), a control diet under HS (NC), a low crude protein (LCP) diet (14% CP in phase 1, 12% CP in phase 2) under HS (LCP) and an LCP diet with increased crystalline AA (an increase in 5% in Lys, Met, Thr and Trp based on calculated SID AA) (LCP5) under HS. Experimental treatments consisted of five replicate pens, with three pigs per pen. The results showed that HS reduced (p < 0.05) growth performance and nutrient digestibility compared to TN. However, LCP5 improved (p < 0.05) growth performance and nutrient digestibility compared to other HS groups. Heat stress adversely affected (p < 0.05) intestinal morphology, gut integrity and serum oxidative markers, but these effects were alleviated (p < 0.05) by LCP5 supplementation. Notably, LCP5 improved (p < 0.05) the production of butyric acids among short-chain fatty acid production and decreased (p < 0.05) proteobacteria and Spirochaetota in phylum in feces. These findings highlight the potential of LCP diets supplemented with crystalline AA as an effective nutritional strategy to mitigate the negative effects of HS on pigs, enhancing their performance, gut health and overall welfare in high-temperature environments.

Emerging Roles of m7G-Cap Hypermethylation and Nuclear Cap-Binding Proteins in Bypassing Suppression of eIF4E-Dependent Translation

Translation regulation is essential to the survival of hosts. Most translation initiation falls under the control of the mTOR pathway, which regulates protein production from mono-methyl-guanosine (m7G) cap mRNAs. However, mTOR does not regulate all translation; hosts and viruses alike employ alternative pathways, protein factors, and internal ribosome entry sites to bypass mTOR. Trimethylguanosine (TMG)-caps arise from hypermethylation of pre-existing m7G-caps by the enzyme TGS1 and are modifications known for snoRNA, snRNA, and telomerase RNA. New findings originating from HIV-1 research reveal that TMG-caps are present on mRNA and license translation via an mTOR-independent pathway. Research has identified TMG-capping of selenoprotein mRNAs, junD, TGS1, DHX9, and retroviral transcripts. TMG-mediated translation may be a missing piece for understanding protein synthesis in cells with little mTOR activity, including HIV-infected resting T cells and nonproliferating cancer cells. Viruses display a nuanced interface with mTOR and have developed strategies that take advantage of the delicate interplay between these translation pathways. This review covers the current knowledge of the TMG-translation pathway. We discuss the intimate relationship between metabolism and translation and explore how this is exploited by HIV-1 in the context of CD4+ T cells. We postulate that co-opting both translation pathways provides a winning strategy for HIV-1 to dictate the sequential synthesis of its proteins and balance viral production with host cell survival.

DDR1 Targeting HOXA6 Facilitates Bladder Cancer Progression via Inhibiting Ferroptosis

Ferroptosis is an important factor affecting the progression of bladder cancer (BC). Previous studies have confirmed that discoidin domain receptor 1 (DDR1) promotes BC progression. However, the regulatory mechanisms of BC ferroptosis are largely unknown. Therefore, this study aimed to investigate the regulatory effects of DDR1 on BC cell ferroptosis. Ferroptosis-sensitive and -resistant BC cells were screened, and reverse-transcription quantitative PCR and western blotting were used to determine the expression of DDR1 in BC cells. In vitro and in vivo assays were performed to analyse the mechanisms of DDR1 in BC ferroptosis. The ferroptosis inducer erastin inhibited DDR1 expression in TCCSUP cells. The ferroptosis inhibitor ferrostatin-1 inhibited BC cell death caused by DDR1 knockdown. DDR1 increased glutathione, glutathione peroxidase 4 and solute carrier family 7 member 11 expression, while decreasing malondialdehyde and Fe2+ levels and acyl-CoA synthetase long-chain family member 4 levels and inhibiting epithelial mesenchymal transition and neurofibromin 2-yes-associated protein. These effects were abrogated by the knockdown of homeobox A6 (HOXA6). DDR1 targeting of HOXA6 facilitated BC growth and inhibited BC ferroptosis in vivo. DDR1 promotes BC progression by inhibiting ferroptosis and targeting HOXA6. Thus, DDR1 may serve as a potential therapeutic target for BC.

Inhibition of ERO1L induces autophagy and apoptosis via endoplasmic reticulum stress in colorectal cancer

Colorectal cancer (CRC) is one of the most common types of cancer with high incidence and mortality. Endoplasmic reticulum oxidoreductase 1 alpha (ERO1L) is overexpressed in CRC. This study aims to explore the role of ERO1L in CRC progression and evaluate the anti-tumor efficacy of the combination treatment of ERO1L inhibition with endoplasmic reticulum (ER) stress-inducing therapies. Herein, we found that ERO1L was elevated in CRC cell lines and patients. ER stress upregulated the expression of ERO1L, and ERO1L deficiency induced ER stress in CRC. ERO1L knockdown increased the susceptibility of CRC cells to ER stress. ERO1L contributed to the malignant phenotypes of CRC cells. Inhibition of ERO1L induced autophagy and caspase-dependent apoptosis by the induction of ER stress in CRC cells. Mechanically, the ERK1/2 pathway was involved in ERO1L knockdown-mediated apoptosis and autophagy. Combination treatment of ERO1L inhibition with ER stress-inducing agents, such as unfolded protein response (UPR)-targeting inhibitors and proteasome inhibitors, demonstrated enhanced anti-tumor capacity. In conclusion, ERO1L is overexpressed in CRC, and ERO1L deficiency induces apoptosis and autophagy via ER stress. ERO1L inhibition combined with ER stress-inducing therapies exhibits more effective anti-tumor activity against CRC. ERO1L may serve as a biomarker and therapeutic target for CRC treatment.

Induction of Triple-Negative Breast Cancer Cell Death and Chemosensitivity Using mTORC2-Directed RNAi Nanomedicine

SIGNIFICANCE

We identified an mTORC2/Rictor-directed RNAi nanomedicine that cooperates with chemotherapy to enhance in vivo tumor cell killing in PI3K-active TNBCs.

Role of miRNAs in Apoptosis Pathways of Immune Cells in Systemic Lupus Erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by dysregulated immune responses and multi-organ involvement. Dysregulation of apoptosis, a key process for maintaining immune homeostasis, plays a critical role in the pathogenesis of SLE. MicroRNAs (miRNAs), small non-coding RNAs that regulate gene expression, have emerged as important modulators of apoptosis in immune cells, influencing the balance between immune tolerance and autoimmunity.

OBJECTIVES

This review aims to comprehensively summarize recent advancements in understanding the roles of miRNAs in apoptosis regulation within immune cells in SLE, highlighting their therapeutic potential for restoring immune balance and mitigating disease progression.

RESULTS

Aberrant expression of specific miRNAs contributes to the dysregulation of apoptosis in SLE immune cells. Pro-apoptotic miRNAs, such as miR-125b and miR-150, are often downregulated, leading to enhanced survival of autoreactive immune cells. Conversely, anti-apoptotic miRNAs, including miR-21, are upregulated, further disrupting the delicate balance of immune cell apoptosis. Dual-function miRNAs, such as miR-155, exhibit context-dependent roles based on cellular environments and target gene interactions. This dysregulation promotes the persistence of autoreactive immune cells and the development of autoimmunity.

CONCLUSIONS

miRNAs play critical roles in modulating apoptosis pathways, making them promising therapeutic targets for SLE. Restoring the balance of pro-apoptotic and anti-apoptotic miRNAs could help reinstate immune tolerance and reduce tissue damage. Future research should focus on elucidating miRNA targetomes, improving delivery systems, and addressing off-target effects to fully harness their therapeutic potential.

The multifaceted role of mitochondria in autism spectrum disorder

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

IL-17A's role in exacerbating radiation-induced lung injury: Autophagy impairment via the PP2A-mTOR pathway

OBJECTIVE

Radiation-induced lung injury (RILI) is a serious complication of radiotherapy, and the role of IL-17A in this process is not well understood. While IL-17A has been shown to modulate autophagy, conflicting reports exist regarding its activation or inhibition of autophagy. This study investigates the role of IL-17A in RILI and its effects on autophagy via the PP2A-mTOR pathway, with a focus on the PP2A B56α subunit.

METHODS

C57BL/6J mice and human lung epithelial cells (BEAS-2B) were exposed to radiation with or without recombinant IL-17A. Autophagy markers were analyzed using Western blotting, immunofluorescence, and autophagy flux assays. PP2A activity, specifically the B56α subunit, was measured. A PP2A agonist (DT-061) was used to verify its role in reversing IL-17A-mediated autophagy inhibition.

RESULTS

IL-17A inhibited autophagy in lung epithelial cells exposed to radiation by suppressing PP2A activity, particularly through downregulation of the B56α subunit, leading to mTOR activation and reduced autophagosome formation. Treatment with DT-061 restored autophagic activity and improved cell viability. These findings align with reports suggesting that IL-17A inhibits autophagy in certain contexts, while other studies have shown opposing effects.

CONCLUSION

IL-17A inhibits autophagy in RILI through the PP2A B56α-mTOR pathway, exacerbating lung damage. Further research is needed to clarify the role of IL-17A in different cell types and conditions. Targeting the IL-17A-PP2A B56α-mTOR axis may offer new therapeutic strategies for RILI management.

Immune imbalance in Lupus Nephritis: The intersection of T-Cell and ferroptosis

Ferroptosis is a novel form of cell death characterized by unlimited accumulation of iron-dependent lipid peroxides. It is often accompanied by disease, and the relationship between ferroptosis of immune cells and immune regulation has been attracting increasing attention. Initially, it was found in cancer research that the inhibition of regulatory T cell (Treg) ferroptosis and the promotion of CD8+ T cell ferroptosis jointly promoted the formation of an immune-tolerant environment in tumors. T-cell ferroptosis has subsequently been found to have immunoregulatory effects in other diseases. As an autoimmune disease characterized by immune imbalance, T-cell ferroptosis has attracted attention for its potential in regulating immune balance in lupus nephritis. This article reviews the metabolic processes within different T-cell subsets in lupus nephritis (LN), including T follicular helper (TFH) cells, T helper (Th)17 cells, Th1 cells, Th2 cells, and Treg cells, and reveals that these cellular metabolisms not only facilitate the formation of a T-cell immune imbalance but are also closely associated with the occurrence of ferroptosis. Consequently, we hypothesize that targeting the metabolic pathways of ferroptosis could become a novel research direction for effectively treating the immune imbalance in lupus nephritis by altering T-cell differentiation and the incidence of ferroptosis.

Tangningtongluo Tablet ameliorates pancreatic damage in diabetic mice by inducing autophagy and inhibiting the PI3K/Akt/mTOR signaling pathway

BACKGROUND

Diabetes is a metabolic disease characterized by hyperglycaemia. Tangningtongluo Tablet (TNTL) is an inpatient formula extensively utilized to treat diabetes mellitus (DM), but the protective mechanism is not clear. This study aimed to investigate the relevant mechanisms by which TNTL affects pancreatic damage in diabetic mice and autophagy.

METHODS

The impact of TNTL on pancreatic damage in diabetic mice in vitro and in vivo was investigated via glucose and lipid metabolism analyses, HE staining, CCK-8, TUNEL staining, Annexin V/PI, and Western blotting. Molecular docking and Western blotting were used to verify the results of network pharmacological analysis, which was carried out to explore the mechanism by which TNTL affects DM. The autophagosome levels were visualized via RFP-GFP-LC3 and transmission electron microscopy, and lysosomal function was evaluated via Lysotracker red staining. Western blot, immunohistochemistry and immunofluorescence staining were used to detect the expression of the autophagy proteins LC3, p62 and LAMP2.

RESULTS

Compared with the model group, TNTL protected pancreas from oxidative stress, decreased the level of MDA, increased the levels of SOD and GSH-px, induced the occurrence of autophagy and decreased the levels of apoptotic factors. Moreover, TNTL inhibited the protein expression of p-PI3K, p-Akt and p-mTOR, increased the levels of LC3 and LAMP2 and decreased the level of p62, and the autophagy inhibitor CQ blocked the protective effect of TNTL on pancreatic damage in diabetic mice.

CONCLUSION

These results demonstrated that TNTL ameliorated pancreatic damage in diabetic mice by inhibiting the PI3K/Akt/mTOR signaling and regulating autophagy.

Integrated multiomics analysis identified comprehensive crosstalk between diverse programmed cell death patterns and novel molecular subtypes in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy with increasing global prevalence and is one of the leading causes of cancer-related mortality in the human population. Developing robust clinical prediction models and prognostic stratification strategies is crucial for developing individualized treatment plans. A range of novel forms of programmed cell death (PCD) plays a role in the pathological progression and advancement of HCC, and in-depth study of PCD is expected to further improve the prognosis of HCC patients. Sixteen patterns (apoptosis, autophagy, anoikis, lysosome-dependent cell death, immunogenic cell death, necroptosis, ferroptosis, netosis, pyroptosis, disulfidptosis, entotic cell death, cuproptosis, parthanatos, netotic cell death, alkaliptosis, and oxeiptosis) related to PCD were collected from the literatures and used for subsequent analysis. Supervised (Elastic net, Random Forest, XgBoost, and Boruta) and unsupervised (Nonnegative Matrix Factorization, NMF) clustering algorithms were applied to develop and validate a novel classifier for the individualized management of HCC patients at the transcriptomic, proteomic and single-cell levels. Multiple machine learning algorithms developed a programmed cell death index (PCDI) comprising five robust signatures (FTL, G6PD, SLC2A1, HTRA2, and DLAT) in four independent HCC cohorts, and a higher PCDI was predictive of higher pathological grades and worse prognoses. Furthermore, a higher PCDI was found to be correlated with the presence of a repressive tumor immune microenvironment (TME), as determined through an integrated examination of bulk and single-cell transcriptome data. In addition, patients with TP53 mutation had higher PCDI in comparison with TP53 WT patients. Three HCC subtypes were identified through unsupervised clustering (NMF), exhibiting distinct prognoses and significant biological processes, among the three subtypes, PCDcluster 3 was of particular interest as it contained a large proportion of patients with high risk and low metabolic activity. Construction and evaluation of the Nomogram model was drawn based on the multivariate logistic regression analysis, and highlighted the robustness of the Nomogram model in other independent HCC cohorts. Finally, to explore the prognostic value, we also validated the frequent upregulation of DLAT in a real-world cohort of human HCC specimens by qPCR, western blot, and immunohistochemical staining (IHC). Together, our work herein comprehensively emphasized PCD-related patterns and key regulators, such as DLAT, contributed to the evolution and prognosis of tumor foci in HCC patients, and strengthened our understanding of PCD characteristics and promoted more effective risk stratification strategies.

DDIT4/mTOR signaling pathway mediates cantharidin-induced hepatotoxicity and cellular damage

Background

Cantharidin (CTD) extracted from the traditional Chinese medicine Mylabris has significant therapeutic effects on various tumors. However, the high toxicity of CTD can cause serious liver damage, although the related molecular mechanisms remain unclear.

Methods

In this study, we established models of CTD-induced liver and L-O2 cell damage in mice in vivo and in vitro. Subsequently, liver function indicators were detected in mouse serum, while liver tissues were subjected to pathological and transmission electron microscopy observations. L-O2 cell activity was investigated using the CCK-8 assay, and the mRNA and protein expression of DNA damage-induced transcription factor 4 (DDIT4) in liver tissue and L-O2 cells was detected using qPCR, immunohistochemistry, and western blotting. Western blotting was also used to detect the expression levels of autophagy- and apoptosis-related proteins in liver tissue and L-O2 cells. After RNAi interference with DDIT4, Rap, and 3-MA treatment, autophagy and apoptosis of L-O2 cells were detected using western blotting, flow cytometry, transmission electron microscopy, and confocal microscopy.

Results

Following CTD exposure, the mouse liver showed significant pathological damage and an increase in autophagic lysosomes, while the vitality of L-O2 cells showed a significant decrease. CTD led to a significant increase in the mRNA and protein levels of DDIT4 in both liver tissue and L-O2 cells, as well as a significant increase in LC3-II, Beclin1, and Bax, whereas p-mTOR and Bcl-2 were significantly decreased. Following DDIT4 interference and 3-MA treatment, the levels of autophagy and apoptosis induced by CTD in L-O2 cells were reduced. After Rap treatment, both autophagy and apoptosis of CTD-induced L-O2 cells were significantly enhanced.

Conclusion

The molecular mechanism of CTD-induced toxicity in mouse liver and L-O2 cells is mainly through DDIT4/mTOR signaling pathway activation, leading to an increase in autophagy and apoptosis levels.

Cytotoxic Autophagy: A Novel Treatment Paradigm against Breast Cancer Using Oleanolic Acid and Ursolic Acid

BACKGROUND

Oleanolic acid (OA) and Ursolic acid (UA) are bioactive triterpenoids. Reported activities vary with the dose used for testing their activities in vitro. Studies using doses of ≥20 µM showed apoptosis activities in cancer cells. However, reported drug levels in circulation achieved by oral administration of UA and OA are ≤2 µM, thus limiting their use for treatment or delivering a combination treatment.

MATERIALS AND METHODS

The present report demonstrates the efficacy of OA, UA, and OA + UA on tumor cell-specific cytotoxicity at low doses (5 µM to 10 µM) in breast cancer (BrCa) cell lines MCF7 and MDA-MB231.

RESULTS

The data show that both OA and UA killed BrCa cells at low doses, but were significantly less toxic to MCF-12A, a non-tumorigenic cell line. Moreover, OA + UA at ≤10 µM was lethal to BrCa cells. Mechanistic studies unraveled the significant absence of apoptosis, but their cytotoxicity was due to the induction of excessive autophagy at a OA + UA dose of 5 µM each. A link to drug-induced cytotoxic autophagy was established by demonstrating a lack of their cytotoxicity by silencing the autophagy-targeting genes (ATGs), which prevented OA-, UA-, or OA + UA-induced cell death. Further, UA or OA + UA treatment of BrCa cells caused an inhibition of PI3 kinase-mediated phosphorylation of Akt/mTOR, the key pathways that regulate cancer cell survival, metabolism, and proliferation.

DISCUSSION

Combinations of a PI3K inhibitor (LY294002) with OA, UA, or OA + UA synergistically inhibited BrCa cell survival. Therefore, the dominance of cytotoxic autophagy by inhibiting PI3K-mediated autophagy may be the primary mechanism of PTT-induced anticancer activity in BrCa cells.

CONCLUSION

These results suggest it would be worthwhile testing combined OA and UA in clinical settings.

Efficacy of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of young pigs

This study aimed to determine the effects of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of pigs. Thirty-two newly weaned pigs at 6.05 ± 0.24 kg were assigned to two dietary treatments based on a randomized complete block design. The treatments were control group receiving a basal diet and a group supplemented with Saccharomyces yeast postbiotics (175 g/ton diet) in the basal diet. After 35 d of the study, pigs were euthanized and jejunal mucosa were collected to assess immune status, oxidative stress, barrier markers, cell proliferation, and apoptosis. Saccharomyces yeast postbiotics reduced (P < 0.05) the fecal score from d 3 to d 7 and tended to increase the gene expression of interferon-γ (IFN-γ) (P = 0.071) and mammalian/mechanistic target of rapamycin (mTOR) (P = 0.080), decrease the gene expression of B-cell lymphoma 2-associated X protein 1 (BAX1) (P < 0.05), tended to decrease the gene expression of serum and glucocorticoid-induced protein kinase 1 (SGK1) (P = 0.066), increased (P < 0.05) cell proliferation in the crypts, and tended to increase the villus height (P = 0.078) and crypt depth (P = 0.052) in the jejunum. In conclusion, the supplementation of Saccharomyces yeast postbiotics in nursery diets reduced diarrhea within the first week after weaning and provided protection to the villi in the jejunum by enhancing the immune responses of nursery pigs, promoting crypt cell proliferation, and reducing the expression of genes associated with apoptosis without affecting inflammatory and oxidative stress status in the jejunum of the nursery pigs.

PDCD4 as a marker of mTOR pathway activation and therapeutic target in mycobacterial infections

Programmed cell death protein 4 (PDCD4) is instrumental in regulating a range of cellular processes such as translation, apoptosis, signal transduction, and inflammatory responses. There is a notable inverse correlation between PDCD4 and the mammalian target of rapamycin (mTOR) pathway, which is integral to cellular growth control. Activation of mTOR is associated with the degradation of PDCD4. Although the role of PDCD4 is well established in oncogenesis and immune response regulation, its function in mycobacterial infections and its interplay with the mTOR pathway necessitate further elucidation. This study investigates the modulation of PDCD4 expression in the context of mycobacterial infections, revealing a consistent pattern of downregulation across diverse mycobacterial species. This observation underscores the potential utility of PDCD4 as a biomarker for assessing mTOR pathway activation during such infections. Building on this finding, we employed a novel approach using PDCD4-based mTOR (Tor)-signal-indicator (TOSI) reporter cells for the high-throughput screening of FDA-approved drugs, focusing on mTOR inhibitors. This methodology facilitated the identification of several agents, inclusive of known mTOR inhibitors, which upregulated PDCD4 expression and concurrently exhibited efficacy in impeding mycobacterial proliferation within macrophages. These results not only reinforce the significance of PDCD4 as a pivotal marker in the understanding of infectious diseases, particularly mycobacterial infections, but also illuminate its potential in the identification of mTOR inhibitors, thereby contributing to the advancement of therapeutic strategies.

IMPORTANCE

This study emphasizes the critical role of the mammalian target of rapamycin (mTOR) pathway in macrophage responses to mycobacterial infections, elucidating how mycobacteria activate mTOR, resulting in PDCD4 degradation. The utilization of the (Tor)-signal-indicator (TOSI) vector for real-time monitoring of mTOR activity represents a significant advancement in understanding mTOR regulation during mycobacterial infection. These findings deepen our comprehension of mycobacteria's innate immune mechanisms and introduce PDCD4 as a novel marker for mTOR activity in infectious diseases. Importantly, this research laid the groundwork for high-throughput screening of mTOR inhibitors using FDA-approved drugs, offering the potential for repurposing treatments against mycobacterial infections. The identification of drugs that inhibit mTOR activation opens new avenues for host-directed therapies, marking a significant step forward in combating tuberculosis and other mycobacterial diseases.

Role of AMPK-regulated autophagy in retinal pigment epithelial cell homeostasis: A review

The retinal pigment epithelium (RPE) is a regularly arranged monolayer of cells in the outermost layer of the retina. It is crucial for transporting nutrients and metabolic substances in the retina and maintaining the retinal barrier. RPE dysfunction causes diseases related to vision loss. Thus, understanding the mechanisms involved in normal RPE function is vital. Adenosine monophosphate-activated protein kinase (AMPK) is an RPE energy sensor regulating various signaling and metabolic pathways to maintain cellular energetic homeostasis. AMPK activation is involved in multiple signaling pathways regulated by autophagy in the RPE, thereby protecting the cells from oxidative stress and slowing RPE degeneration. In this review, we attempt to broaden the understanding of the pathogenesis of RPE dysfunction by focusing on the role and mechanism of AMPK regulation of autophagy in the RPE. The correlation between RPE cellular homeostasis and role of AMPK was determined by analyzing the structure and mechanism of AMPK and its signaling pathway in autophagy. The protective effect of AMPK-regulated autophagy on the RPE for gaining insights into the regulatory pathways of RPE dysfunction has been discussed.

Current state of knowledge of triclosan (TCS)-dependent reactive oxygen species (ROS) production

Triclosan (TCS) is widely used in a number of industrial and personal care products. This molecule can induce reactive oxygen species (ROS) production in various cell types, which results in diverse types of cell responses. Therefore, the aim of the present study was to summarize the current state of knowledge of TCS-dependent ROS production and the influence of TCS on antioxidant enzymes and pathways. To date, the TCS mechanism of action has been widely investigated in non-mammalian organisms that may be exposed to contaminated water and soil, but there are also in vivo and in vitro studies on plants, algae, mammalians, and humans. This literature review has revealed that mammalian organisms are more resistant to TCS than non-mammalian organisms and, to obtain a toxic effect, the effective TCS dose must be significantly higher. The TCS-dependent increase in the ROS level causes damage to DNA, protein, and lipids, which together with general oxidative stress leads to cell apoptosis or necrosis and, in the case of cancer cells, faster oncogenesis and even initiation of oncogenic transformation in normal human cells. The review presents the direct and indirect TCS action through different receptor pathways.

Pseudolaric acid B suppresses NSCLC progression through the ROS/AMPK/mTOR/autophagy signalling pathway

Pseudolaric acid B (PAB), an acid isolated from the roots of Pseudolarix kaempferi gorden, has shown antitumour effects through multiple mechanisms of action. The objective of this study was to investigate the anticancer effect of PAB on non-small cell lung cancer (NSCLC) and its underlying mechanism. In our experiments, we observed that PAB decreased cell viability, inhibited colony formation, induced cell cycle arrest, impeded scratch healing, and increased apoptosis in H1975 and H1650 cells. Additionally, PAB treatment enhanced the fluorescence intensity of MDC staining in NSCLC cells, upregulated the protein expression of microtubule-associated protein light chain 3 II (LC3 II), and downregulated the expression of sequestosome 1 (SQSTM1/P62). Combined treatment with PAB and chloroquine (CQ) increased the protein expression levels of LC3 II and P62 while decreasing the apoptosis of H1975 and H1650 cells. Moreover, treatment with PAB led to significant mTOR inhibition and AMPK activation. PAB combined with compound C (CC) inhibited autophagy and apoptosis. Furthermore, PAB treatment increased intracellular reactive oxygen species (ROS) levels in NSCLC cells, which correlated with the modulation of the AMPK/mTOR signalling pathway and was associated with autophagy and apoptosis. Finally, we validated the antitumour growth activity and mechanism of PAB in vivo using athymic nude mice bearing H1975 tumour cells. In conclusion, our findings suggest that PAB can induce apoptosis and autophagic cell death in NSCLC through the ROS-triggered AMPK/mTOR signalling pathway, making it a promising candidate for future NSCLC treatment.

Relationship of mTORC1 and ferroptosis in tumors

Ferroptosis is a novel form of programmed death, dependent on iron ions and oxidative stress, with a predominant intracellular form of lipid peroxidation. In recent years, ferroptosis has gained more and more interest of people in the treatment mechanism of targeted tumors. mTOR, always overexpressed in the tumor, and controlling cell growth and metabolic activities, has an important role in both autophagy and ferroptosis. Interestingly, the selective types of autophay plays an important role in promoting ferroptosis, which is related to mTOR and some metabolic pathways (especially in iron and amino acids). In this paper, we list the main mechanisms linking ferroptosis with mTOR signaling pathway and further summarize the current compounds targeting ferroptosis in these ways. There are growing experimental evidences that targeting mTOR and ferroptosis may have effective impact in many tumors, and understanding the mechanisms linking mTOR to ferroptosis could provide a potential therapeutic approach for tumor treatment.

Low crude protein formulation with supplemental amino acids for its impacts on intestinal health and growth performance of growing-finishing pigs

BACKGROUND

Low crude protein (CP) formulations with supplemental amino acids (AA) are used to enhance intestinal health, reduce costs, minimize environmental impact, and maintain growth performance of pigs. However, extensive reduction of dietary CP can compromise growth performance due to limited synthesis of non-essential AA and limited availability of bioactive compounds from protein supplements even when AA requirements are met. Moreover, implementing a low CP formulation can increase the net energy (NE) content in feeds causing excessive fat deposition. Additional supplementation of functional AA, coupled with low CP formulation could further enhance intestinal health and glucose metabolism, improving nitrogen utilization, and growth performance. Three experiments were conducted to evaluate the effects of low CP formulations with supplemental AA on the intestinal health and growth performance of growing-finishing pigs.

METHODS

In Exp. 1, 90 pigs (19.7 ± 1.1 kg, 45 barrows and 45 gilts) were assigned to 3 treatments: CON (18.0% CP, supplementing Lys, Met, and Thr), LCP (16.0% CP, supplementing Lys, Met, Thr, Trp, and Val), and LCPT (16.1% CP, LCP + 0.05% SID Trp). In Exp. 2, 72 pigs (34.2 ± 4.2 kg BW) were assigned to 3 treatments: CON (17.7% CP, meeting the requirements of Lys, Met, Thr, and Trp); LCP (15.0% CP, meeting Lys, Thr, Trp, Met, Val, Ile, and Phe); and VLCP (12.8% CP, meeting Lys, Thr, Trp, Met, Val, Ile, Phe, His, and Leu). In Exp. 3, 72 pigs (54.1 ± 5.9 kg BW) were assigned to 3 treatments and fed experimental diets for 3 phases (grower 2, finishing 1, and finishing 2). Treatments were CON (18.0%, 13.8%, 12.7% CP for 3 phases; meeting Lys, Met, Thr, and Trp); LCP (13.5%, 11.4%, 10.4% CP for 3 phases; meeting Lys, Thr, Trp, Met, Val, Ile, and Phe); and LCPG (14.1%, 12.8%, 11.1% CP for 3 phases; LCP + Glu to match SID Glu with CON). All diets had 2.6 Mcal/kg NE.

RESULTS

In Exp. 1, overall, the growth performance did not differ among treatments. The LCPT increased (P < 0.05) Claudin-1 expression in the duodenum and jejunum. The LCP and LCPT increased (P < 0.05) CAT-1, 4F2hc, and B0AT expressions in the jejunum. In Exp. 2, overall, the VLCP reduced (P < 0.05) G:F and BUN. The LCP and VLCP increased (P < 0.05) the backfat thickness (BFT). In Exp. 3, overall, growth performance and BFT did not differ among treatments. The LCPG reduced (P < 0.05) BUN, whereas increased the insulin in plasma. The LCP and LCPG reduced (P < 0.05) the abundance of Streptococcaceae, whereas the LCP reduced (P < 0.05) Erysipelotrichaceae, and the alpha diversity.

CONCLUSIONS

When implementing low CP formulation, CP can be reduced by supplementation of Lys, Thr, Met, Trp, Val, and Ile without affecting the growth performance of growing-finishing pigs when NE is adjusted to avoid increased fat deposition. Supplementation of Trp above the requirement or supplementation of Glu in low CP formulation seems to benefit intestinal health as well as improved nitrogen utilization and glucose metabolism.

Molecular Mechanism of Resveratrol and Its Therapeutic Potential on Female Infertility

Resveratrol is a polyphenol present in various plant sources. Studies have reported numerous potential health benefits of resveratrol, exhibiting anti-aging, anti-inflammatory, anti-microbial, and anti-carcinogenic activity. Due to the reported effects, resveratrol is also being tested in reproductive disorders, including female infertility. Numerous cellular, animal, and even human studies were performed with a focus on the effect of resveratrol on female infertility. In this review, we reviewed some of its molecular mechanisms of action and summarized animal and human studies regarding resveratrol and female infertility, with a focus on age-related infertility, polycystic ovary syndrome, and endometriosis.

Enriched oxygen improves age-related cognitive impairment through enhancing autophagy

Age-related cognitive impairment represents a significant health concern, with the understanding of its underlying mechanisms and potential interventions being of paramount importance. This study aimed to investigate the effects of hyperbaric oxygen therapy (HBOT) on cognitive function and neuronal integrity in aged (22-month-old) C57BL/6 mice. Male mice were exposed to HBOT for 2 weeks, and spatial learning and memory abilities were assessed using the Morris water maze. We employed transcriptome sequencing and Gene Ontology (GO) term enrichment analysis to examine the effects of HBOT on gene expression profiles, with particular attention given to synapse-related genes. Our data indicated a significant upregulation of postsynapse organization, synapse organization, and axonogenesis GO terms, likely contributing to improved cognitive performance. Moreover, the hyperphosphorylation of tau, a hallmark of many neurodegenerative diseases, was significantly reduced in the HBO-treated group, both in vivo and in vitro. Transmission electron microscopy revealed significant ultrastructural alterations in the hippocampus of the HBOT group, including an increase in the number of synapses and the size of the active zone, a reduction in demyelinated lesions, and a decreased number of "PANTHOS." Furthermore, Western blot analyses confirmed the upregulation of PSD95, BDNF, and Syn proteins, suggesting enhanced synaptic plasticity and neurotrophic support. Moreover, HBOT increased autophagy, as evidenced by the elevated levels of Beclin-1 and LC3 proteins and the reduced level of p62 protein. Finally, we demonstrated that HBOT activated the AMPK-mTOR signaling pathway, a critical regulator of autophagy. Notably, our findings provide novel insights into the mechanisms by which HBOT ameliorates age-related cognitive impairment, suggesting the potential therapeutic value of this approach.

Crosstalk between autophagy and metabolism: implications for cell survival in acute myeloid leukemia

Acute myeloid leukemia (AML), a prevalent form of leukemia in adults, is often characterized by low response rates to chemotherapy, high recurrence rates, and unfavorable prognosis. A critical barrier in managing refractory or recurrent AML is the resistance to chemotherapy. Increasing evidence indicates that tumor cell metabolism plays a crucial role in AML progression, survival, metastasis, and treatment resistance. Autophagy, an essential regulator of cellular energy metabolism, is increasingly recognized for its role in the metabolic reprogramming of AML. Autophagy sustains leukemia cells during chemotherapy by not only providing energy but also facilitating rapid proliferation through the supply of essential components such as amino acids and nucleotides. Conversely, the metabolic state of AML cells can influence the activity of autophagy. Their mutual coordination helps maintain intrinsic cellular homeostasis, which is a significant contributor to chemotherapy resistance in leukemia cells. This review explores the recent advancements in understanding the interaction between autophagy and metabolism in AML cells, emphasizing their roles in cell survival and drug resistance. A comprehensive understanding of the interplay between autophagy and leukemia cell metabolism can shed light on leukemia cell survival strategies, particularly under adverse conditions such as chemotherapy. This insight may also pave the way for innovative targeted treatment strategies.

MAD2L2, a key regulator in ovarian cancer and promoting tumor progression

Ovarian cancer (OVCA), a prevalent gynecological malignancy, ranks as the fourth most common cancer among women. Mitotic Arrest Deficient 2 Like 2 (MAD2L2), a chromatin-binding protein and a component of DNA polymerase ζ, has been previously identified as an inhibitor of tumor growth in colorectal cancer. However, the roles of MAD2L2 in OVCA, including its expression, impact, and prognostic significance, remain unclear. We employed bioinformatics tools, Cox Regression analysis, and in vitro cell experiments to investigate its biological functions. Our findings reveal that MAD2L2 typically undergoes genomic alterations, such as amplifications and deep deletions. Moreover, we observed an overexpression of MAD2L2 mRNA in OVCA patients, correlating with reduced survival rates, particularly in those with Grade IV tumors. Furthermore, analysis of mRNA biofunctions indicated that MAD2L2 is predominantly localized in the organellar ribosome, engaging mainly in NADH dehydrogenase activity. This was deduced from the results of gene ontology enrichment analysis, which also identified its role as a structural constituent in mitochondrial translation elongation. These findings were corroborated by KEGG pathway analysis, further revealing MAD2L2's involvement in tumor metabolism and the cell death process. Notably, MAD2L2 protein expression showed significant associations with various immune cells, including CD4+T cells, CD8+T cells, B cells, natural killer cells, and Myeloid dendritic cells. Additionally, elevated levels of MAD2L2 were found to enhance cell proliferation and migration in OVCA cells. The upregulation of MAD2L2 also appears to inhibit the ferroptosis process, coinciding with increased mTOR signaling activity in these cells. Our study identifies MAD2L2 as a novel regulator in ovarian tumor progression and offers new insights for treating OVCA.

Anti-Tumor Effect and Mechanism Study of Caloric Restriction, Achieved by Time-Restricted Feeding, in Mice

OBJECTIVE

To evaluate the therapeutic effects and explore the mechanisms behind caloric restriction achieved through time-restricted feeding (CR) in inhibiting mouse tumors, providing a theoretical basis and data support for future CR diet-assisted anticancer treatment protocols.

METHODS

C57BL/6 and BALB/c mice were divided into four cell line groups. Each group was further split into normal diet (ND) and a CR diet groups. The ND groups had free access to water and a normal diet, while the CR diet groups had access to water but were only fed from 9 a.m. to 11 a.m., fasting for the remaining 22 h. Food intake was recorded daily starting on day 1 of the experiment. Tumor models were established and assessed every 2 days. Blood biochemical indicators, serum pyruvic acid levels, and cytokine expression were measured.

RESULTS

The CR diet inhibited tumor growth in mice. Colorimetric assays and ELISAs showed a reduction in pyruvic acid levels and in key upstream and downstream rate-limiting enzymes in the sera of CR mice. Routine blood and blood biochemistry tests suggested minor effects of the CR diet on these parameters. Western blotting revealed that the CR diet suppressed mTOR and AKT protein expression in tumor tissues. ELISA showed that various mTOR-related signaling pathways were downregulated. Immunohistochemistry staining indicated reduced expression of P53, P-AKT, EGFR, and IGF-1 in tumor tissues. TUNEL staining confirmed that the CR diet promoted tumor apoptosis.

CONCLUSION

The CR diet inhibited tumor growth by suppressing mTOR and its related upstream and downstream gene signaling pathways, reducing tumor glycolysis, and accelerating tumor cell apoptosis.