Expression Of LC3-II Research Articles

Dendrobium nobile Lindl. alkaloids protect CCl4-induced acute liver injury via upregulating LAMP1 expression and activating autophagy flux.

Dendrobium nobile Lindl. alkaloids (DNLA) are considered important active ingredients of Dendrobium, which have a variety of pharmacological functions. Recent studies indicate that DNLA has beneficial activity in acute liver injury. However, the specific mechanism by which DNLA produces liver protective effects is stills unclear. This study was designed to determine whether regulation of autophagy is involved in the mode of action of DNLA in liver protection. Using CCl4-induced acute liver injury (ALI) and cell culture models, the molecular mechanism of DNLA-mediated autophagy regulation was studied. The results showed that DNLA significantly improved CCl4-induced liver damage and oxidative stress, which was confirmed in AML-12 cells. DNLA promoted autophagy in cells treated with CCl4, manifested by reduced protein expressions of p62 and LC3-II. Fluorescence imaging showed a decrease in the number of autophagosomes in AML-12 cells transfected with mCherry-GFP-LC3B. In addition, DNLA inhibited lysosomal membrane permeabilization by upregulating lysosomal associated membrane protein-1 (LAMP1), thereby promoting autophagy, preventing CCl4-induced mitochondrial dysfunction, and reducing the production of mitochondrial reactive oxygen species (ROS). While pretreatment of cells with lysosomal inhibitor chloroquine weakened mitochondrial protection elicited by DNLA, overexpression of mitochondrial-targeted SOD2 in AML-12 cells significantly blocked CCl4 induced downregulation of LAMP1, thereby improving lysosome integrity and promoting lysosome dependent autophagy, suggesting that there may exist a bidirectional regulation between mitochondrial ROS and lysosome-autophagy activation. Collectively, these results demonstrated that DNLA can protect the liver injury mediated by dysregulation of lysosome-autophagy process through promoting ROS-lysosome-autophagy axis and improving mitochondrial damage.

Ultrasound-targeted sirolimus-loaded microbubbles improves acute rejection of heart transplantation in rats by inhibiting TGF-β1-Smad signaling pathway, promoting autophagy and reducing inflammation

Acute rejection (AR) remains a pivotal complication and leading cause of mortality within the first year following heart transplantation (HT). In this study, we assessed the impact of ultrasound-targeted microbubbles loaded with sirolimus (SIR-MBs) on AR in a rat HT model and delved into the underlying mechanisms. We established a rat abdominal ectopic HT model, which was stratified into three groups receiveing the PBS, SIR-MBs + ultrasound-targeted microbubble destruction (UTMD), and sirolimus, respectively. The protective effects of each treatments on survival rate, inflammatory response, autophagy and TGF-β1-Smad signaling pathway-related proteins were evaluted. Additionally, rescue experiment was performed via adding the autophagy inhibitor or TGF-β1 agonist in combination therapy. UTMD combined SIR-MBs mediated 15-fold higher local drug concentration compared to direct sirolimus administration. The infiltration of inflammatory cells in the transplanted hearts indicated that SIR-MBs combined with UTMD were effective in mitigating the inflammatory response, achieving levels significantly lower than those observed in the sirolimus group. Furthermore, after SIR-MBs combined with UTMD treatment, the expression levels of TGF-β1-Smad signaling pathway-related proteins in heart tissues also showed a significant decrease compared to the model control group. Conversely, the expressions of autophagy proteins LC3-II, Beclin-1 and β-arrestin showed an up-regulated trend. Rescue experiments also revealed that the enhancement in survival trends was markedly suppressed following the administration of CsA or SRI-011381, respectively. Collectively, our findings suggest that SIR-MBs combined with UTMD augment the local treatment efficacy for AR in rat HT models by inhibiting the TGF-β1-Smad signaling pathway, promoting autophagy, and alleviating inflammation.

Low molecular weight Fucoidan induces M2 macrophage polarization to attenuate inflammation through activation of the AMPK/mTOR autophagy pathway.

Fucoidan, a sulfated polysaccharide with a complex structure, has gradually become the focus of biomedical research due to its remarkable biological activity and low toxicity. In this research, it was noted that low molecular weight fucoidan (LMWF) exhibited significant antimicrobial effects on Methicillin-resistant Staphylococcus aureus (MRSA) and promoted polarization towards M2 macrophages, leading to a substantial reduction in inflammatory responses within the lipopolysaccharide (LPS)-activated macrophages. We further explored the mechanism underlying the anti-inflammation activity. Our findings indicated that LMWF significantly enhanced the phosphorylation level of AMP-activated protein kinase (AMPK), inhibited the phosphorylation of the mammalian target of rapamycin (mTOR), and enhanced the expression of LC3II. Meanwhile, Compound C (CC) substantially reversed the anti-inflammation effect of LMWF, indicating that the AMPK pathway plays a pivotal role in this effect. In in vivo research, LMWF revealed impressive anti-inflammatory potential. LMWF treatment significantly eliminated MRSA and ameliorated inflammatory symptoms in mice's MRSA-infected skin wound model. Further analysis using Western Blot (WB) indicated significant AMPK/mTOR signaling pathway activation in mice treated with LMWF, which led to accelerated polarization of macrophages from the M1 to the M2 phenotype. In summary, we systematically explored the mechanism by which LMWF exerts anti-inflammatory effects through in vitro and in vivo experiments. It was confirmed that LMWF effectively induced the conversion of macrophages to an anti-inflammatory M2 phenotype by activating the AMPK/mTOR pathway. Simultaneously, LMWF effectively eradicated MRSA and accelerated wound healing in mice. This finding provides an important theoretical basis for further research on fucoidan.

Activation of α7 Nicotinic Acetylcholine Receptor Augments Nerve Growth Factor Action on PCtrk Cells

Although cigarette smoking is known to be a critical risk factor for various organ systems and cancers, accumulating evidence indicates that nicotine – a main constituent of cigarette smoking – can exert neuroprotective effects on neuronal cells through nicotinic acetylcholine receptors (nAChRs). However, the precise molecular mechanisms for nicotinic neuroprotective actions remain to be fully elucidated. In this study, we examine the effects of agonists, such as nicotine and PNU282987, on tropomyosin-related kinase (Trk)-dependent neuroprotective pathways in PC12 cells overexpressing a Trk neurotrophin receptor (PCtrk cells). We found that even considerably higher concentrations (mM range for nicotine and µM range for PN282987) of nAChR agonists exert favorable effects, such as the augmentation of nerve growth factor (NGF)-induced Trk neurotrophin receptor autophosphorylation of tyrosine residues and NGF-induced neurite extension. Moreover, nicotine upregulated reactive oxygen species (ROS) levels in the cells. ROS production was completely cancelled by pretreatment with Mito-Tempo, a mitochondria-targeted antioxidant, indicating that the main source of ROS production by nicotine was mitochondria. Furthermore, treatment with nAChR agonists appeared to induce autophagic flux, as evidenced by the upregulation of LC3-II expression in cells. Furthermore, sucrose density ultracentrifugation of nicotine-treated cells clearly disclosed the augmented recruitment of α7nAChR protein into the lipid rafts fraction of the membrane. Intriguingly, a pull-down assay of anti-Trk antibody immunoprecipitates clearly included α7nAChR protein, indicating that Trk and α7nAChR proteins form a complex. These results reveal a new molecular interaction between activated α7nAChR and Trk protein that may serve as a new molecular basis of nicotine-induced neuroprotective action.

A Selective Melatonin 2 Receptor Agonist, IIK7, Relieves Blue Light-Induced Corneal Damage by Modulating the Process of Autophagy and Apoptosis

This study aims to investigate the effect of the selective MT2 receptor agonist, IIK7, on corneal autophagy and apoptosis, aiming to reduce corneal epithelial damage and inflammation from blue light exposure in mice. Eight-week-old C57BL/6 mice were divided into BL-exposed (BL) and BL-exposed with IIK7 treatment (BL + IIK7 group). Mice underwent blue light exposure (410 nm, 100 J) twice daily with assessments at baseline and on days 3, 7, and 14. Corneal samples were analyzed for MT2 receptor expression, autophagy markers (LC3-II and p62), and apoptosis indicators (BAX expression and TUNEL assay). Then, mice were assigned to normal control, BL, and BL + IIK7. Ocular surface parameters, including corneal fluorescein staining scores, tear volume, and tear film break-up time, were evaluated on days 7 and 14. On day 14, reactive oxygen species (ROS) levels and CD4+ IFN-γ+ T cells percentages were measured. The BL group exhibited higher LC3-II and p62 expression, while the BL + IIK7 group showed reduced expression (p < 0.05). The TUNEL assay showed reduced apoptosis in the BL + IIK7 group compared to the BL group. ROS levels were lower in the BL + IIK7 group. The BL + IIK7 group showed improved ocular surface parameters, including decreased corneal fluorescein staining and increased tear volume. The percentages of CD4+ IFN-γ+ T cells indicated reduced inflammatory responses in the BL + IIK7 group. The MT2 receptor agonist IIK7 regulates corneal autophagy and apoptosis, reducing corneal epithelial damage and inflammation from blue light exposure.

Growth differentiation factor 11 alleviates oxidative stress-induced senescence of endothelial progenitor cells via activating autophagy

BackgroundStem cell transplantation has been regarded as a promising therapeutic strategy for myocardial regeneration after myocardial infarction (MI). However, the survival and differentiation of the transplanted stem cells in the hostile ischaemic and inflammatory microenvironment are poor. Recent studies have focused on enhancing the survival and differentiation of the stem cells, while strategies to suppress the senescence of the transplanted stem cells is unknown. Therefore, we investigated the effect of growth differentiation factor 11 (GDF11) on attenuating oxidative stress-induced senescence in the engrafted endothelial progenitor cells (EPCs).MethodsRat models of oxidative stress were established by hydrogen peroxide conditioning. Oxidative stress-induced senescence was assessed through senescence-associated β-galactosidase expression and lipofuscin accumulation. The effects of GDF11 treatment on senescence and autophagy of EPCs were evaluated 345, while improvement of myocardial regeneration, neovascularization and cardiac function were examined following transplantation of the self-assembling peptide (SAP) loaded EPCs and GDF11 in the rat MI models.ResultsFollowing hydrogen peroxide conditioning, the level of ROS in EPCs decreased significantly upon treatment with GDF11. This resulted in reduction in the senescent cells and lipofuscin particles, as well as the damaged mitochondria and rough endoplasmic reticula. Concurrently, there was a significant increase in LC3-II expression, LC3-positive puncta and the presence of autophagic ultrastructures were increased significantly. The formulated SAP effectively adhered to EPCs and sustained the release of GDF11. Transplantation of SAP-loaded EPCs and GDF11 into the ischaemic abdominal pouch or myocardium resulted in a decreased number of the senescent EPCs. At four weeks after transplantation into the myocardium, neovascularization and myocardial regeneration were enhanced, reverse myocardial remodeling was attenuated, and cardiac function was improved effectively.ConclusionsThis study provides novel evidence suggesting that oxidative stress could induce senescence of the transplanted EPCs in the ischemic myocardium. GDF11 demonstrates the ability to mitigate oxidative stress-induced senescence in the transplanted EPCs within the myocardium by activating autophagy.

The role of AKR1B10 in osteogenic differentiation of mesenchymal stem cells and atrophic nonunion

Atrophic nonunion is a chronic disease without effective medications. Here, high-throughput mRNA sequencing was used to explore the novel targets in atrophic nonunion. AKR1B10, a member of aldo-keto reductase family 1, is upregulated in atrophic nonunion tissues. There are currently no studies to reveal the role of AKR1B10 in atrophic nonunion. We used rat bone marrow-derived mesenchymal stem cells (BMSCs) to explore the effect of AKR1B10 on the osteogenic differentiation and autophagy. In vivo, we implanted collagen sponges loaded with LV-shAKR1B10-transduced BMSCs into rat fractured femurs to explore the role of AKR1B10 in fracture healing. The results showed that AKR1B10 reduced the activity of ALP, suppressed the expression of COL1A1, RUNX2 and OCN, and inhibited calcification deposition in osteogenically differentiated BMSCs. AKR1B10 reduced the expression of LC3II, decreased the number of autophagosomes, and promoted the expression of p62. In addition, the promoting effect of AKR1B10 knockdown on osteogenic differentiation of BMSCs was attenuated by 3-MA treatment. Implantation of collagen sponges found that knockdown of AKR1B10 promoted bone fracture healing. In conclusion, AKR1B10 inhibited the osteogenic differentiation and autophagy, and delayed the bone fracture healing. These results provide a new perspective on revealing the role of AKR1B10 in nonunion and may also provide a new therapeutic target for the treatment of nonunion.

9317 Diabetogenic Stress-Mediated Beta Cell Extracellular Vesicle:Autophagy Pathway Crosstalk

Abstract Disclosure: A. Roy: None. G. Ariyaratne: None. A. Matveyenko: None. N. Javeed: None. Diabetogenic stressors including elevated free fatty acids (lipotoxicity), low-grade systemic inflammation, and proteotoxicity are central to the development of Type 2 Diabetes (T2D). Due to their high protein synthetic burden, β-cells employ autophagy and endo/lysosomal pathways to reduce protein aggregates, and protect β-cell mass and function. Recently, extracellular vesicles (EVs; 30-150 nm sized nanoparticles) have been shown to work in tandem with autophagy to facilitate cellular adaptation and intercellular communication. As diabetogenic stressors have been shown to perturb autophagy via lysosomal defects, our group has noted enhanced EV secretion. Thus, we hypothesize that diabetogenic factors enhance EV secretion through activation of an EV-based secretory autophagy pathway and that re-balancing of both pathways could improve β-cell function in T2D. To test this, MIN6 cells were exposed to free fatty acid palmitate (PAL; 24h), or pro-inflammatory cytokines IL-1β, TNFα, and IFNγ (CYTO; 48h). Expression of autophagic markers, LC3 and p62 were increased in CYTO and PAL conditions suggesting defects in auto/lysosomal function. Upon PAL/CYTO treatment in MIN6 cells, conditioned media EVs were isolated using differential ultracentrifugation. We noted enhanced protein expression of LC3-II and p62 in PAL- and cytoEVs, suggesting a diversion of immature autophagosome components into EVs due to lysosomal inhibition. To restore balance between autophagy:EV flux, we used EV biogenesis inhibitor, GW4869 (GW; 24h) or autophagy inducer, rapamycin (Rapa; 24h) on MIN6 cells exposed to PAL or CYTO. Isolated EVs were subjected to Nanoparticle Tracking Analysis (NTA) which showed a significant reduction in EV concentration with GW or Rapa addition (p<.05). Isolated mouse islet exposed to CYTO+GW/Rapa or PAL+GW/Rapa showed significant improvements in glucose stimulated insulin secretion (vs. CYTO or PAL; p<.05). Taken together, these data implicate activation of EV-based secretory autophagy in response to diabetogenic stressors and thus, potential targets to improve functional β-cell mass. Presentation: 6/2/2024

BL-918 alleviates oxidative stress in rats after subarachnoid hemorrhage by promoting mitophagy through the ULK1/PINK1/Parkin pathway

Background and purposeOxidative stress plays a critical role in early brain injury (EBI) following subarachnoid hemorrhage (SAH). The small molecule ULK1 agonist, BL-918, demonstrated neuroprotective effects in other central nervous system diseases; however, its role in SAH has not yet been explored. This study aimed to evaluate whether BL-918 could provide neuroprotective effects in rats following SAH. MethodsAn SAH model was established in Sprague-Dawley rats using endovascular perforation. BL-918 was administered intraperitoneally after SAH, while the ULK1 inhibitor SBI was given intraperitoneally prior to SAH modeling. PINK1 siRNA was administered into the lateral ventricle before SAH induction. The neuroprotective effects and mechanisms of BL-918 were assessed through SAH grading, brain water content measurement, blood-brain barrier permeability, neurobehavioral tests, Western blot, immunofluorescence, TUNEL staining, DHE staining, and transmission electron microscopy (TEM). ResultsAfter SAH, the expression levels of p-ULK1, PINK1, Parkin, and LC3Ⅱ increased, peaking at 24 h post-SAH. BL-918 treatment improved neurological function in rats, reduced brain water content and blood-brain barrier permeability, and exhibited anti-oxidative stress and anti-apoptotic effects. Western blot analysis revealed that BL-918 increased the expression of p-ULK1, PINK1, Parkin, LC3Ⅱ, Bcl-xl, and Bcl-2 while inhibiting the expression of Bax and Cleaved Caspase-3. Oxidative stress-related indicators showed that BL-918 alleviated oxidative stress. Immunofluorescence and TEM results demonstrated that BL-918 promoted mitophagy and preserved mitochondrial morphology. Furthermore, the positive effects of BL-918 were reversed by SBI and PINK1 siRNA, respectively. ConclusionBL-918 improved both short-term and long-term neurological impairments in rats after SAH and reduced oxidative stress by promoting mitophagy, at least partially through the ULK1/PINK1/Parkin signaling pathway.

Laherradurin Inhibits Colorectal Cancer Cell Growth by Induction of Mitochondrial Dysfunction and Autophagy Induction.

CRC cells were treated with LAH, and its effects on mitochondrial respiration and glycolysis were measured using Seahorse XF technology. The changes in mitochondrial dynamics were observed through fluorescent imaging, while Western blot analysis was used to examine key autophagy and apoptosis markers. LAH significantly inhibited mitochondrial complex I activity, inducing ATP depletion and a compensatory increase in glycolysis. This disruption caused mitochondrial fragmentation, a trigger for autophagy, as shown by increased LC3-II expression and mTOR suppression. Apoptosis was also confirmed through the cleavage of caspase-3, contributing to reduced cancer cell viability. LAH's anticancer effects in CRC cells are driven by its disruption of mitochondrial function, triggering both autophagy and apoptosis. These findings highlight its potential as a therapeutic compound for further exploration in cancer treatment.

Curcumin inhibits oxidative stress and autophagy in C17.2 neural stem cell through ERK1/2 signaling pathways.

This study investigates curcumin's neuroprotective role and its potential in promoting neurogenesis in progenitor cells within the brain. Notably, curcumin's antioxidant properties have been implicated in Alzheimer's disease treatment. However, the association between curcumin's antioxidative effects and its impact on neural stem cells (NSCs) remains to be elucidated. C17.2 neural stem cells were utilized as a model to simulate oxidative stress, induced by hydrogen peroxide (H2O2). We quantified the levels of superoxide dismutase (SOD), malondialdehyde (MDA), and intracellular reactive oxygen species (ROS), alongside the gene expression of SOD1 and SOD2, to assess intracellular oxidative stress. Additionally, Western blot analysis was conducted to measure the expressions of LC3-II, Beclin-1, and phosphorylated ERK (p-ERK), thereby evaluating autophagy and ERK signaling pathway activation. Treatment with curcumin resulted in a reduction of MDA and ROS levels, suggesting a protective effect on NSCs against oxidative damage induced by H2O2. Furthermore, a decrease in the relative expressions of LC3-II, Beclin-1, and p-ERK was observed post-curcumin treatment. The findings suggest that curcumin may confer protection against oxidative stress by attenuating autophagy and deactivating the ERK1/2 signaling pathways, which could contribute to therapeutic strategies for Alzheimer's disease.

LncRNA MIAT suppresses inflammation in LPS-induced J774A.1 macrophages by promoting autophagy through miR-30a-5p/SOCS1 axi

Accumulated data implicate that long noncoding RNA (lncRNA) plays a pivotal role in rheumatoid arthritis (RA), potentially serving as a competitive endogenous RNA (ceRNA) for microRNAs (miRNAs). The lncRNA myocardial infarction-associated transcript (MIAT) has been demonstrated to regulate inflammation. However, the role of MIAT in the inflammation of RA remains inadequately explored. This study aims to elucidate MIAT’s role in the inflammation of lipopolysaccharide (LPS)-induced macrophages and to uncover the underlying molecular mechanisms. We observed heightened MIAT expression in LPS-induced J774A.1 cells and collagen-induced arthritis mouse models, in contrast to the expression pattern of miR-30a-5p. Silencing MIAT resulted in increased expression of the inflammatory cytokines IL-1β and TNF-α. Simultaneously, MIAT interference significantly impeded macrophage autophagy, evidenced by decreased expression of autophagy-related markers LC3-II and Beclin-1, alongside increased levels of p62 in LPS-induced J774A.1 cells. Notably, MIAT functioned as a ceRNA, sponging miR-30a-5p and exerting a negative regulatory influence on its expression. SOCS1 emerged as a target of miR-30a-5p, modulated by MIAT. Mechanistically, inhibiting miR-30a-5p reversed the impact of MIAT deficiency in promoting LPS-induced inflammation, while SOCS1 knockdown countered the cytokine inhibitory effect induced by silencing miR-30a-5p. In summary, this study indicates that lncRNA MIAT suppresses inflammation in LPS-induced J774A.1 macrophages by stimulating autophagy through the miR-30a-5p/SOCS1 axis. This suggests that MIAT holds promise as a potential therapeutic target for RA inflammation.

Targeting NCAPD2 as a Therapeutic Strategy for Crohn's Disease: Implications for Autophagy and Inflammation.

Our earlier studies identified that non-SMC condensin I complex subunit D2 (NCAPD2) induces inflammation through the IKK/NF-κB pathway in ulcerative colitis. However, its role in the development of Crohn's disease (CD) and the specific molecular mechanism still need to be further studied. NCAPD2 expression in clinical ileal CD mucosa vs normal mucosa was examined, alongside its correlation with CD patients' clinical characteristics via their medical records. The biological function and molecular mechanism of NCAPD2 in CD were explored using a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD mouse model, along with immunofluorescence, western blot, quantitative real-time PCR, immunohistochemistry, hematoxylin and eosin staining, and cell functional analysis. NCAPD2 was overexpressed in CD tissues and significantly correlated with disease activity in CD patients (P = .016). In a TNBS-induced CD mouse model, NCAPD2 knockdown inhibited the development of TNBS-induced intestinal inflammation in mice. In addition, we found that NCAPD2 inhibited autophagy. Mechanistically, NCAPD2 promoted the phosphorylation of mammalian target of the rapamycin (mTOR) and its direct effector S6K and downregulated the expression of autophagy-related proteins Beclin1, LC3II, and Atg5. In addition, NCAPD2 activates the NF-κB signaling pathway, and the downstream inflammatory factors are continuously released, leading to the persistence of inflammation. Our results show that NCAPD2 suppresses autophagy and worsens intestinal inflammation by modulating mTOR signaling and impacting the NF-κB pathway, suggesting a critical role in CD progression. Targeting NCAPD2 could be a promising therapeutic approach to stop CD advancement.

Dipsacoside B Attenuates Atherosclerosis by Promoting Autophagy to Inhibit Macrophage Lipid Accumulation.

Atherosclerosis is a chronic inflammatory disease characterized by lipid accumulation and foam cell formation in the arterial wall. Promoting macrophage autophagy has emerged as a promising therapeutic strategy against atherosclerosis. Dipsacoside B (DB) is an oleanane-type pentacyclic triterpenoid saponin extracted from Lonicerae flos with potential anti-atherosclerotic properties. In this study, we investigated the effects of DB on atherosclerosis progression in ApoE-/- mice fed a high-fat diet and explored the underlying mechanisms in oxidized low-density lipoprotein (ox-LDL)-induced foam cells. DB treatment significantly reduced atherosclerotic lesion size, improved plaque stability, and regulated lipid metabolism without impairing liver and kidney function in ApoE-/- mice. In vitro studies revealed that DB dose-dependently inhibited ox-LDL internalization and intracellular lipid accumulation in RAW264.7 macrophages. Mechanistically, DB induced autophagy, as evidenced by increased autophagosome formation and upregulated expression of autophagy markers LC3-II and p62 both in vivo and in vitro. Inhibition of autophagy by chloroquine abolished the antiatherosclerotic and pro-autophagic effects of DB. Furthermore, DB treatment increased LC3-II and p62 mRNA levels, suggesting transcriptional regulation of autophagy. Collectively, our findings demonstrate that DB exerts anti-atherosclerotic effects by inhibiting foam cell formation via autophagy induction, providing new insights into the pharmacological actions of DB and its potential as a therapeutic agent against atherosclerosis.

Sacubitril/valsartan attenuated myocardial inflammation, fibrosis, apoptosis and promoted autophagy in doxorubicin-induced cardiotoxicity mice via regulating the AMPKα-mTORC1 signaling pathway.

This study aimed to investigate the potential cardioprotective effects of sacubitril/valsartan (Sac/Val) in mice with doxorubicin (DOX)-induced cardiomyopathy, a common manifestation of cancer therapy-related cardiac dysfunction (CTRCD) associated with DOX. A total of thirty-two mice were equally classified into 4 groups: control group, DOX (total 24mg/kg), Sac/Val (80mg/kg), and Sac/Val + DOX (Sac/Val was given from seven days before doxorubicin administration). Neonatal rat ventricular myocytes was exposed to 5µM of DOX for 6h in vitro to mimic the in vivo conditions. A variety of techniques were used to investigate cardiac inflammation, fibrosis, apoptosis, and autophagy, including western blot, real-time quantitative PCR (RT-qPCR), immunohistochemistry, and fluorescence. Mice with DOX-induced cardiotoxicity displayed impaired systolic and diastolic function, characterized by elevated levels of cardiac inflammation, fibrosis, cardiomyocyte hypertrophy, apoptosis, and autophagy inhibition in the heart. Treatment with Sac/Val partially reversed these effects. In comparison to the control group, the protein expression of NLRP3, caspase-1, collagen I, Bax, cleaved caspase-3, and P62 were significantly increased, while the protein expression of Bcl-2 and LC3-II were significantly decreased in the myocardial tissues of the Dox-induced cardiomyopathy group. The administration of Sac/Val demonstrated the potential to partially reverse alterations in protein expression within the myocardium of mice with DOX-induced cardiotoxicity by modulating the AMPKα-mTORC1 signaling pathway and suppressing oxidative stress. Additionally, Sac/Val treatment may mitigate Dox-induced apoptosis and inhibition of autophagy in primary cardiomyocytes. Sac/Val seems to be cardioprotective against DOX-induced cardiotoxicity in the pre-treatment mice model. These findings could be attributed to the anti-inflammatory, antioxidant, anti-apoptotic, and de-autophagy effects of Sac/Val through regulation of the AMPKα-mTORC1 signaling pathway.

SIRT7 remodels the cytoskeleton via RAC1 to enhance host resistance to Mycobacterium tuberculosis.

Phagocytosis of Mycobacterium tuberculosis (Mtb) followed by its integration into the matured lysosome is critical in the host defense against tuberculosis. How Mtb escapes this immune attack remains elusive. In this study, we unveiled a novel regulatory mechanism by which SIRT7 regulates cytoskeletal remodeling by modulating RAC1 activation. We discovered that SIRT7 expression was significantly reduced in CD14+ monocytes of TB patients. Mtb infection diminished SIRT7 expression by macrophages at both the mRNA and protein levels. SIRT7 deficiency impaired actin cytoskeleton-dependent macrophage phagocytosis, LC3II expression, and bactericidal activity. In a murine tuberculosis model, SIRT7 deficiency detrimentally impacted host resistance to Mtb, while Sirt7 overexpression significantly increased the host defense against Mtb, as determined by bacterial burden and inflammatory-histopathological damage in the lung. Mechanistically, we demonstrated that SIRT7 limits Mtb infection by directly interacting with and activating RAC1, through which cytoskeletal remodeling is modulated. Therefore, we concluded that SIRT7, in its role regulating cytoskeletal remodeling through RAC1, is critical for host responses during Mtb infection and proposes a potential target for tuberculosis treatment.IMPORTANCETuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a significant global health issue. Critical to macrophages' defense against Mtb is phagocytosis, governed by the actin cytoskeleton. Previous research has revealed that Mtb manipulates and disrupts the host's actin network, though the specific mechanisms have been elusive. Our study identifies a pivotal role for SIRT7 in this context: Mtb infection leads to reduced SIRT7 expression, which, in turn, diminishes RAC1 activation and consequently impairs actin-dependent phagocytosis. The significance of our research is that SIRT7 directly engages with and activates Rac Family Small GTPase 1 (RAC1), thus promoting effective phagocytosis and the elimination of Mtb. This insight into the dynamic between host and pathogen in TB not only broadens our understanding but also opens new avenues for therapeutic development.

Hesperetin regulates PI3K/Akt and mTOR pathways to exhibit its antiproliferative effect against colon cancer cells

ABSTRACT Hesperetin, a citrus flavonoid, has been a widely studied anticancer agent against many types of cancers, but the exact mechanism of efficacy is still unrevealed. Therefore, this study has attempted to delineate the mechanical aspect of hesperetin’s anticancer efficacy against colon cancer using immunoblotting, scanning, and transmission electron microscopic studies. The treatment with hesperetin (25 and 50 µM) has significantly (p < 0.0001) curbed down the proliferation and cell viability of HCT-15 cells in a concentration as well as time dependent manner. Hesperetin was able to achieve this through the induction of caspase-dependent apoptosis. Moreover, hesperetin effectively inhibited phosphorylation of Akt with a parallel increase in PTEN expression thereby inhibiting the PI3K signaling axis, which contributes to the suppression of proliferation. In addition, hesperetin enhanced autophagy through dephosphorylating mTOR, one of the downstream targets of Akt with simultaneous acceleration in Beclin-1 and LC3-II expression levels. Interestingly, hesperetin enhanced the effects of Akt inhibitor LY294002 and mTOR inhibitor rapamycin. This study documented the potential of hesperetin to induce apoptosis through simultaneous acceleration over the autophagic process in colon cancer cells. Thus, hesperetin played a beneficial therapeutic role in preventing colon carcinoma growth by regulating the Akt and mTOR signaling axis.

Overexpression of long noncoding RNA DUXAP8 inhibits ER-phagy through activating AKT/mTOR signaling and contributes to preeclampsia

Preeclampsia (PE) is a life-threatening pregnancy-specific complication with controversial mechanisms and no effective treatment except delivery is available. Currently, increasing researchers suggested that PE shares pathophysiologic features with protein misfolding/aggregation disorders, such as Alzheimer disease (AD). Evidences have proposed defective autophagy as a potential source of protein aggregation in PE. Endoplasmic reticulum-selective autophagy (ER-phagy) plays a critical role in clearing misfolded proteins and maintaining ER homeostasis. However, its roles in the molecular pathology of PE remain unclear. We found that lncRNA DUXAP8 was upregulated in preeclamptic placentae and significantly correlated with clinical indicators. DUXAP8 specifically binds to PCBP2 and inhibits its ubiquitination-mediated degradation, and decreased levels of PCBP2 reversed the activation effect of DUXAP8 overexpression on AKT/mTOR signaling pathway. Function experiments showed that DUXAP8 overexpression inhibited trophoblastic proliferation, migration, and invasion of HTR-8/SVneo and JAR cells. Moreover, pathological accumulation of swollen and lytic ER (endoplasmic reticulum) was observed in DUXAP8-overexpressed HTR8/SVneo cells and PE placental villus trophoblast cells, which suggesting that ER clearance ability is impaired. Further studies found that DUXAP8 overexpression impaired ER-phagy and caused protein aggregation medicated by reduced FAM134B and LC3II expression (key proteins involved in ER-phagy) via activating AKT/mTOR signaling pathway. The increased level of FAM134B significantly reversed the inhibitory effect of DUXAP8 overexpression on the proliferation, migration, and invasion of trophoblasts. In vivo, DUXAP8 overexpression through tail vein injection of adenovirus induced PE-like phenotypes in pregnant rats accompanied with activated AKT/mTOR signaling, decreased expression of FAM134B and LC3-II proteins and increased protein aggregation in placental tissues. Our study reveals the important role of lncRNA DUXAP8 in regulating trophoblast biological behaviors through FAM134B-mediated ER-phagy, providing a new theoretical basis for understanding the pathogenesis of PE.

Morin overcomes doxorubicin resistance in human breast cancer by inducing DNA damage and modulating the LKB1/AMPK/mTORC1 signaling pathway.

Breast cancer chemoresistance hampers chemotherapy efficacy; researchers investigate the pharmacological activities of natural products for potential solutions. This study aimed to determine the effect of morin, a bioflavonoid isolated from Maclura pomifera, on two Dox-resistant human breast cancer cell lines MDA-MB-231 (MDA-DR) and MCF-7 (MCF-DR). Sulforhodamine B and colony-forming assays demonstrated the cytotoxic effect of morin on both cell lines. Morin induced DNA damage and reduced the DNA repair mechanism, a feature of chemoresistance. In addition, morin reduced the protein expressions of cell cycle regulators, such as cyclin D1, CDK4, cyclin E1, cyclin B1, and p-Rb, thereby halting cell cycle progression. Moreover, morin slightly reduced PARP and Bcl-xL expressions but left LC3-II and RIPK3 expressions unchanged. Annexin-V/7-AAD analysis showed morin increased 7-AAD positive cells and annexin-V positive cells among MDA-DR and MCF-DR cells, respectively. In addition, morin increased p-AMPK and p-LKB1 levels; and, thus, inhibited phosphorylation of the mTOR pathway, but decreased t-AMPK levels by inducing lysosomal degradation, and AICAR, an AMPK activator, reduced Raptor, cyclin D1, CDK4, cyclin E1 and phosphorylated, and total mTOR levels, indicating AMPK is a key player in inducing cell death. Also, morin modulated MAPK phosphorylation and attenuated p-Akt and p-GSK3αβ levels; and thus, inhibited cell survival. In addition, morin suppressed tumor growth in our MDA-DR xenografted mouse model. These findings indicate that morin is a potential treatment for Dox-resistant breast cancer and that it does so by inducing DNA damage and modulating the LKB1/AMPK/mTORC1 pathway, along with regulating the MAPK, and Akt/GSK3αβ signaling pathways.

Treatment with autophagic inhibitors enhances oligonol‑induced apoptotic effects in nasopharyngeal carcinoma cells.

Although the combination of chemotherapy and radiotherapy has increased the survival rate of patients with nasopharyngeal carcinoma (NPC), certain patients do not respond well to the treatment and have a poor prognosis. Therefore, novel therapeutic drugs and strategies to improve prognosis of patients with NPC are required. As certain plant extracts can suppress the viability of cancer cells, the present study investigated whether oligonol, a polyphenolic compound primarily found in lychee fruit, exerts anticancer activities in NPC cells. MTT, ELISA and immunoblotting were performed to investigate cell survival, cytokeratin-18 fragment release, and the expression of apoptosis and autophagy markers, respectively. Oligonol decreased the viability of NPC-TW01 and NPC/HK1NPC cell lines. Oligonol increased the protein expression of several apoptosis markers, including cleaved caspase-8 and -3, cleaved PARP and cytokeratin 18 fragment. Moreover, it also increased expression of autophagy markers Beclin 1 and LC3-II, as well as LC3-II/LC3-I ratio in both NPC cell lines. Furthermore, treatment with autophagy inhibitors 3-methyladenine or LY294002 significantly increased oligonol-induced viability inhibition in NPC-TW01 cells. Combined treatment of oligonol + LY294002 reduced LC3-II expression and the LC3II/LC3I ratio while increasing cleaved caspase-8 and -3, cleaved PARP and cytokeratin 18 fragment expression in NPC-TW01 cells. These findings indicated autophagy inhibitors could enhance viability inhibition and apoptotic effects induced by oligonol in NPC cells.