Autophagy: cellular and molecular mechanisms

Nitric oxide synthase 1 inhibits the progression of esophageal cancer through interacting with nitric oxide synthase 1 adaptor protein

BACKGROUND

Esophageal cancer (ESCA) is among the most prevalent and lethal tumors globally. While nitric oxide synthase 1 (NOS1) is recognized for its important involvement in various cancers, its specific function in ESCA remains unclear.

AIM

To explore the potential role and underlying mechanisms of NOS1 in ESCA.

METHODS

Survival rates were analyzed using GeneCards and Gene Expression Profiling Interactive Analysis. The effects and mechanisms of NOS1 on ESCA cells were evaluated via the Cell Counting Kit-8 assay, scratch assay, Transwell assay, flow cytometry, quantitative polymerase chain reaction, western blotting, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining. The protein interaction network was used to screen the interacting proteins of NOS1 and validate these interactions through co-immunoprecipitation and dual luciferase assays. Additionally, a nude mouse xenograft model was established to evaluate the effect of NOS1 in vivo.

RESULTS

The survival rate of patients with ESCA with high NOS1 expression was higher than that of patients with low NOS1 expression. NOS1 expression in ESCA cell lines was lower than that in normal esophageal epithelial cells. Overexpression of NOS1 (oe-NOS1) inhibited proliferation, invasion, and migration abilities in ESCA cell lines, resulting in decreased autophagy levels and increased apoptosis, pyroptosis, and ferroptosis. Protein interaction studies confirmed the interaction between NOS1 and NOS1 adaptor protein (NOS1AP). Following oe-NOS1 and the silencing of NOS1AP, levels of P62 and microtubule-associated protein 1 light chain 3 beta increased both in vitro and in vivo. Furthermore, the expression levels of E-cadherin, along with the activation of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT), were inhibited in ESCA cell lines.

CONCLUSION

NOS1 and NOS1 proteins interact to suppress autophagy, activate the PI3K/AKT pathway, and exert anti-cancer effects in ESCA.

High-fat stimulation induces atrial structural remodeling via the TPM1/P53/SHISA5 Axis

BACKGROUND

Atrial structural remodeling plays a central role in the development and progression of atrial fibrillation (AF) and significantly influences its course. Hyperlipidemia, a potential contributor to AF, affects cardiac function through multiple pathways. This study aimed to investigate the underlying mechanisms by which high lipid levels promote AF progression.

METHODS

In vitro cell models were established using palmitic acid (PA) stimulation, and in vivo rat models were generated by feeding a high-fat diet (HFD). Proteomic and transcriptomic sequencing analyses were conducted to identify differentially expressed proteins and genes. Extracellular vesicles (EVs) were isolated and characterized by differential centrifugation. Cell proliferation was assessed using EdU incorporation and flow cytometry, while transmission electron microscopy (TEM) was used to observe autophagy. Protein expression was analyzed by immunoblotting, immunohistochemistry, and immunofluorescence.

RESULTS

High lipid stimulation significantly increased the expression of tropomyosin 1 (TPM1) in cardiomyocytes, which was transferred to cardiac fibroblasts via EVs, activating the P53/SHISA5 signaling axis and inducing endoplasmic reticulum (ER) stress and autophagy, thereby promoting atrial structural remodeling. Activation of P53 and overexpression of SHISA5 in human cardiac fibroblast (HCF) cells reduced ER stress, autophagy, and fibrosis. Furthermore, ER stress and autophagy markers were significantly elevated in the atrial tissues of HFD-fed rats, while SHISA5 overexpression mitigated these effects.

CONCLUSION

High-fat stimulation may induce atrial fibrosis through the TPM1/P53/SHISA5 axis by modulating the ER stress-autophagy pathway.

Autophagy in adult stem cell homeostasis, aging, and disease therapy

Autophagy is a crucial cellular process that facilitates the degradation of damaged organelles and protein aggregates, and the recycling of cellular components for the energy production and macromolecule synthesis. It plays an indispensable role in maintaining cellular homeostasis. Over recent decades, research has increasingly focused on the role of autophagy in regulating adult stem cells (SCs). Studies suggest that autophagy modulates various cellular processes and states of adult SCs, including quiescence, proliferation, self-renewal, and differentiation. The primary role of autophagy in these contexts is to sustain homeostasis, withstand stressors, and supply energy. Notably, the dysfunction of adult SCs during aging is correlated with a decline in autophagic activity, suggesting that autophagy is also involved in SC- and aging-associated disorders. Given the diverse cellular processes mediated by autophagy and the intricate mechanisms governing adult SCs, further research is essential to elucidate both universal and cell type-specific regulatory pathways of autophagy. This review discusses the role of autophagy in regulating adult SCs during quiescence, proliferation, self-renewal, and differentiation. Additionally, it summarizes the relationship between SC aging and autophagy, providing therapeutical insights into treating and ameliorating aging-associated diseases and cancers, and ultimately promoting longevity.

Understanding chronic inflammation: couplings between cytokines, ROS, NO, Cai 2+, HIF-1α, Nrf2 and autophagy

Chronic inflammation is an important component of many diseases, including autoimmune diseases, intracellular infections, dysbiosis and degenerative diseases. An important element of this state is the mainly positive feedback between inflammatory cytokines, reactive oxygen species (ROS), nitric oxide (NO), increased intracellular calcium, hypoxia-inducible factor 1-alpha (HIF-1α) stabilisation and mitochondrial oxidative stress, which, under normal conditions, enhance the response against pathogens. Autophagy and the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant response are mainly negatively coupled with the above-mentioned elements to maintain the defence response at a level appropriate to the severity of the infection. The current review is the first attempt to build a multidimensional model of cellular self-regulation of chronic inflammation. It describes the feedbacks involved in the inflammatory response and explains the possible pathways by which inflammation becomes chronic. The multiplicity of positive feedbacks suggests that symptomatic treatment of chronic inflammation should focus on inhibiting multiple positive feedbacks to effectively suppress all dysregulated elements including inflammation, oxidative stress, calcium stress, mito-stress and other metabolic disturbances.

Induction of cellular autophagy impairs TGF-β1-mediated extracellular matrix deposition in primary human knee fibroblasts

Aims

To evaluate the role of autophagy in primary knee fibroblasts undergoing myofibroblast differentiation as an in vitro model of arthrofibrosis, a complication after total knee arthroplasty characterized by aberrant intra-articular scar tissue formation and limited range of motion.

Methods

We conducted a therapeutic screen of autophagic-modulating therapies in primary human knee fibroblasts undergoing transforming growth factor-beta 1 (TGF-β1)-mediated myofibroblast differentiation. Autophagy was induced pharmacologically with rapamycin or by amino acid deprivation. Picrosirius red staining was performed to quantify collagen deposition. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to evaluate fibrotic gene expression levels.

Results

Rapamycin, an mTOR complex 1 (mTORC1) inhibitor and autophagy inducer, reduced TGF-β1-mediated collagen deposition. Interestingly, we simultaneously report that myofibrogenic genes, including ACTA2, were highly upregulated following rapamycin-TGF-β1 treatment. When autophagy was induced through amino acid deprivation, we demonstrated suppressed extracellular matrix levels, fibrotic gene expression (e.g. ACTA2), and SMAD2 phosphorylation levels in TGF-β1-stimulated fibroblasts.

Conclusion

Our findings demonstrate that the induction of cellular autophagy suppresses TGF-β1-induced collagen deposition in primary human knee fibroblasts. Taken together, these data suggest that cellular autophagy may be prophylactic against the pathogenesis of arthrofibrosis.

Modified weiling decoction inhibited excessive autophagy via AKT/mTOR/ULK1 pathway to alleviate T2DM: Integrating network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Weiling Decoction is a traditional Chinese herbal formula that has the function of removing dampness and transforming turbidity, and it is widely used in the treatment of metabolic diseases. The hypoglycemic and antihyperlipidemic effects of Modified Weiling Decoction (MWLD) have been clinically verified in patients with type 2 diabetes mellitus (T2DM), however, the molecular mechanism remains unclear.

AIM OF THE STUDY

To explore the hypoglycemic mechanism of MWLD based on integrative network pharmacology and experimental validation in vivo and in vitro.

MATERIALS AND METHODS

The overlap between T2DM-related genes and target genes of MWLD were deemed to the potential targets of MWLD in alleviating T2DM. Protein-protein interaction analysis was performed to find the core targets from above-mentioned potential targets, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and Gene Ontology (GO) analysis were carried out to gain the key pathways involved in the T2DM improvement by MWLD. T2DM mice and palmitic acid-induced HepG2 cells were employed to validate the mechanism of MWLD predicated by network pharmacology.

RESULTS

A total of 292 target genes from 113 bioactive compounds in MWLD were identified, among of which 42 genes were recognized as core genes of MWLD in ameliorating T2DM. KEGG analysis showed that the therapeutic effect of MWLD on T2DM may be associated with insulin resistance (IR), islet β cell dysfunction, AKT, and MAPK. We found that MWLD significantly reduced fasting blood glucose and improved oral glucose tolerance in T2DM mice. Meanwhile, MWLD activated the AKT/GSK3β pathway to increase liver glycogen production and improve glucose metabolism in T2DM mice. MWLD activated the AKT/mTOR/ULK1 signaling pathway and reversed the increase of autophagy associated proteins (LC3II, Beclin1, Cathepsin B, and LAMP2) in the liver of T2DM mice. Similar results were also confirmed palmitic acid-induced HepG2 cells, an in vitro model for IR. Conversely, AKT inhibitor MK2206 neutralized the effects of MWLD on autophagy and glucose uptake, which was consistent with these results that the main active components of MWLD show strong affinity with AKT1 analyzed by molecular docking.

CONCLUSION

Both in vivo and in vitro experiments showed that MWLD inhibited excessive autophagy through the AKT/mTOR/ULK1 pathway to improve hepatic IR, and stimulate liver glycogen production through AKT/GSK3β pathway.

Selenium pretreatment improve renal function, autophagy signaling pathway and mir21a gene expression in renal ischemia reperfusion injury model in male rat

BACKGROUND

Renal ischemia-reperfusion injury (RIRI) is a major cause of acute kidney injury (AKI). Autophagy is an important mechanisms involved in this damage. In this study, we investigated effect of selenium on autophagy in kidney following IRI.

METHODS

In this study, 24 Wistar male rats (200 ± 20 gr) were divided into 4 groups: 1) Sham 2) Sham+ Sodium selenite (0.5 mg/kg) 3) Ischemia-reperfusion (I/R) 4) I/R + sodium selenite. RIRI induces by vascular microclamp for 45 min. At the end of study, blood was taken from the heart tissue and used to measure BUN and Creatinine with the kit, the left kidney tissue was frozen for measurement of LC3II, LC3I, Beclin1, Rab11a, P62, and Caspase3 by western blot technique and measurement of mir21a by RT-PCR method. In addition, right kidney tissue was placed in formalin for histological studies with Haematoxylin‎‎-eosin staining.

RESULT

According to the results, in the I/R group compared to the sham group, serum levels of creatinine and urea, amount of autophagy including expression levels of Lc3II/Lc3I, beclin1, Rab11a, Cleaved Caspase3/Pro Caspase3 proteins significantly increased and expression of p62 decreased. Also, mir21a gene expression significantly decreased in the I/R group. According to histological results, ischemia-reperfusion has caused kidney tissue damage, such as destruction of the brush border of renal tubules, congestion, and leukocyte filtration. Our results showed that pretreatment with selenium reduced tissue damage and moderated the expression changes of the mentioned proteins.

CONCLUSION

It seems selenium inhibits autophagy by changing the expression levels of mediator molecules Rab11a and mir21a, and it can apply its healing effects in the damage caused by ischemia and reperfusion of kidney tissue in an animal model.

Whole transcriptome analysis of Mycoplasma bovis-host interactions under in vitro and in vivo conditions

Mycoplasma bovis mastitis is becoming increasingly problematic for dairy cattle farming. M. bovis is inherently resistant to beta-lactam antimicrobials and no effective vaccine is available. The major constraints to developing effective control tools are limited knowledge of M. bovis virulence factors and the underlying pathogenic mechanisms. The objective of this study was to determine virulence-associated genes of M. bovis and host immune response genes expressed during the early stages of host-pathogen interactions. We conducted in vitro infection of mammary epithelial cell (MAC-T) lines and in vivo intramammary infection of dairy cows with M. bovis strain PG45 and evaluated whole transcriptome differential gene expression. A total of 614 and 7161 genes of M. bovis and bovine host cells were differentially expressed, respectively. Insertion sequence (IS) genes that are involved in transposase activity such as ISMbov1, ISMbov2, ISMbov3, and ISMbov9 were significantly upregulated, whereas protein translation-associated genes were significantly downregulated. In MAC-T cells, genes involved in apoptosis pathways and proinflammatory cytokines were significantly upregulated, whereas genes involved in cell cycle, ribosome biogenesis, and steroid biosynthesis were significantly downregulated. Genes encoding formation of neutrophil extracellular traps and proinflammatory cytokines, were significantly upregulated in the mammary gland of M. bovis challenged cows, whereas genes involved in steroid biosynthesis and metabolism were significantly downregulated. Altogether, while our findings shed light on the simultaneous transcriptional changes in M. bovis and the host during infection, further studies are required to understand a complete picture of these interactions that lead to mastitis.

Astragaloside IV inhibits nasopharyngeal carcinoma progression by suppressing the SATB2/Wnt signaling axis

Astragaloside IV (AS-IV), a major bioactive component of Astragalus membranaceus, exhibits anti-cancer and anti-inflammatory properties. However, its precise role in nasopharyngeal carcinoma (NPC) remains unclear. This study investigated the effects of AS-IV on NPC progression and its relationship with Special AT-rich binding protein-2 (SATB2), a diagnostic marker for NPC. AS-IV treatment reduced NPC cell viability in a dose-dependent manner, as assessed by CCK-8 assays. Functional experiments, including transwell, immunofluorescence, and flow cytometry assays, demonstrated that AS-IV inhibited cell migration, invasion, and autophagy while promoting apoptosis. Western blot analysis showed that SATB2 expression was significantly elevated in NPC cells, particularly in C666-1 and HK-1 cells. Overexpression of SATB2 partially reversed AS-IV's inhibitory effects on NPC progression. Further analysis revealed that AS-IV suppressed the Wnt signaling pathway by downregulating SATB2 expression, while SATB2 overexpression restored Wnt pathway activation. This effect was reversed upon treatment with the Wnt pathway inhibitor DKK-1. In vivo, AS-IV administration inhibited tumor growth in a nude mouse subcutaneous xenograft model, reduced Ki-67 positivity, and lowered LC3B expression, indicating decreased proliferation and autophagy. However, these effects were diminished upon SATB2 overexpression. These findings suggest that AS-IV exerts anti-tumor effects in NPC by downregulating SATB2 and suppressing Wnt pathway activation, highlighting its potential as a therapeutic agent for NPC.

Highlights

Astragaloside IV (AS-IV) reduces nasopharyngeal carcinoma (NPC) cell vitality, suppresses cell migration, invasion and autophagy, and fosters apoptosis.SATB2 exhibits notably high levels in NPC cells.Overexpression of SATB2 counteracts the inhibition of NPC malignant progression by AS-IV.AS-IV impedes NPC progression by decreasing SATB2 and thereby hindering the Wnt pathway.AS-IV deters NPC tumor growth in nude mice.

Cannabidiol Enhances the Anticancer Activity of Etoposide on Prostate Cancer Cells

Introduction: Cannabis sativa extract has been used as an herbal medicine since ancient times. It is one of the most researched extracts, especially among supportive treatments against cancer. Prostate cancer is one of the most frequently diagnosed cancer types in men worldwide and an estimated 288,300 new cases were diagnosed in 2023. Today, many advanced therapeutic approaches are used for prostate cancer, such as immunotherapy and chemotherapy, but acquired drug resistance, long-term drug usage and differentiation of cancer cells mostly restricted the efficiency of therapies. Therefore, it is thought that the use of natural products to overcome these limitations and improve the effectiveness of existing therapies may offer promising approaches. The present study focused on the investigation of the possible enhancer role of cannabidiol (CBD), which is a potent ingredient compound of Cannabis, on the chemotherapeutic agent etoposide in prostate cancer cells. Methods: Herein, we tested the potentiator role of CBD on etoposide in prostate cancer cells by testing the cytotoxic effect, morphological alterations, apoptotic effects, autophagy, unfolded protein response (UPR) signaling, endoplasmic reticulum-associated degradation mechanism (ERAD), angiogenic and androgenic factors, and epithelial-mesenchymal transition (EMT). In addition, we examined the combined treatment of CBD and etoposide on colonial growth, migrative, invasive capability, 3D tumor formation, and cellular senescence. Results: Our findings demonstrated that cotreatment of etoposide with CBD importantly suppressed autophagic flux and induced ERAD and UPR signaling in LNCaP cells. Also, CBD strongly enhanced the etoposide-mediated suppression of androgenic signaling, angiogenic factor VEGF-A, protooncogene c-Myc, EMT, and also induced apoptosis through activation caspase-3 and PARP-1. Moreover, coadministration markedly decreased tumorigenic properties, such as proliferative capacity, colonial growth, migration, and 3D tumor formation and also induced senescence. Altogether, our data revealed that CBD has a potent enhancer effect on etoposide-associated anticancer activities. Conclusion: The present study suggests that the use of CBD as a supportive therapy in existing chemotherapeutic approaches may be a promising option, but this effectiveness needs to be investigated on a large scale.

Palmatine activation of TFEB enhances autophagy and alleviates endoplasmic reticulum stress in intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IDD) is integral in lower back pain and involves complex pathophysiological processes, including nucleus pulposus (NP) cell apoptosis and extracellular matrix (ECM) breakdown. Palmatine (PLT), an isoquinoline alkaloid extracted from Fibraurea recisa Pierre of the family Menispermaceae, is recognised for its anti-inflammatory, antioxidant, and neuroprotective effects. Nevertheless, researches have not well explored the impact of PLT on IDD.

OBJECTIVE

This investigation aimed at determining the impact of PLT on oxidative stress caused by tert‑butyl hydroperoxide (TBHP) and exploring its potential as a therapeutic agent and its mechanisms in IDD.

METHODS

Potential anti-IDD targets of PLT were identified using network pharmacology and bioinformatics methods and evaluated using Gene Ontology analysis. The method of molecular docking helped elucidate the interaction mode and connections between PLT and transcription factor EB (TFEB). Cellular thermal shift assays and cycloheximide chase experiments confirmed direct interactions between PLT and TFEB. NP cell apoptosis, ECM levels, endoplasmic reticulum stress (ERS), autophagy, and TFEB expression were evaluated using western blotting, TUNEL staining, EdU staining, flow cytometry, immunofluorescence, and alcian blue staining. Functional IDD recovery was evaluated using MRI and X-ray, haematoxylin-eosin (HE) staining, safranin O/fast green staining, and immunohistochemical (IHC) staining. Moreover, needle puncture was used to establish an in vivo rat model of IDD to examine the therapeutic efficacy of PLT.

RESULTS

PLT markedly mitigated ERS and inhibited TBHP-induced ECM degradation and NP cell apoptosis by activating TFEB and upregulating autophagy. In the IDD rat model, PLT improved annulus fibrosus (AF) and NP morphology and structure.

CONCLUSION

These findings demonstrate that PLT alleviates IDD progression by upregulating TFEB; therefore, TFEB represents a potential novel therapeutic target. Moreover, this study reveals for the first time that PLT inhibits ERS by enhancing TFEB-mediated autophagy, thereby reducing NP cell apoptosis and ECM degradation, thus providing valuable insights into the key pharmacological mechanisms of PLT.

Mechanisms and functional implications of ZDHHC5 in cellular physiology and disease

Post-translational lipid modification by palmitoylation is a reversible process crucial for maintaining cellular functionality. The palmitoyl acyltransferase zinc finger Asp-His-His-Cys motif-containing 5 (ZDHHC5) has garnered significant attention due to its roles in neurodegenerative diseases, oncogenesis, and cardiac function. ZDHHC5 recognizes substrates through diverse mechanisms and its activity is regulated by multiple factors. Highly expressed in the brain, liver, and heart, ZDHHC5 exerts regulatory functions in various cellular processes through self-regulation and substrate palmitoylation. This review summarizes ZDHHC5's regulatory roles in the nervous system, lipid metabolism and oncogenesis, highlighting its potential as a therapeutic target for neurological, lipid metabolic diseases, and cancer due to its involvement in diverse cellular processes and disease-associated dysfunctions.

TRIM7 knockdown protects against LPS-induced autophagy, ferroptosis, and inflammatory responses in human bronchial epithelial cells

Asthma is one of the most common respiratory diseases in pediatric department. Several asthma-associated events including inflammatory responses, autophagy, and ferroptosis have been identified as typical pathological processes. TRIM7 is a member of TRIM proteins family associated with several types of diseases. Nevertheless, its role in asthma is still elusive. The current research showed that TRIM7 was involved in the pathogenesis of asthma mainly by regulating the Akt signaling pathway. In detail, we found that TRIM7 was highly expressed in patients with asthma and in an in vitro model of asthma. The following analysis indicated that TRIM7 knockdown attenuated the expression and secretion of inflammatory cytokines including TNF-α, IL-1β and IL-6 in lipopolysaccharide (LPS)-exposed human bronchial epithelial cells (HBECs). Meanwhile, knockdown of TRIM7 exerted inhibitory effects on LPS-induced autophagy and ferroptosis. Further mechanistic studies showed that TRIM7 knockdown inhibited LPS-induced activation of Akt pathway, while overexpression of Akt attenuated the inhibitory effects of TRIM7 knockdown on LPS-exposed HBECs. Collectively, we reported here that TRIM7 knockdown inhibited LPS-induced autophagy, ferroptosis, and inflammatory cytokine secretion in HBECs via regulating the Akt pathway, providing a new insight into the strategies for improving asthma treatments.

Improving ferroptosis-mediated immunotherapy for colorectal cancer through lysosome-targeted photodynamic therapy

Lysosomes is emerging as a promising therapeutic target for improving immunotherapy, which dysfunction would trigger lysosomal membrane permeabilization increase and subsequent leakage of reduced iron, which contributed to ferroptosis through cell-intrinsic Fenton chemistry. However, the integrity of lysosomal membranes is not susceptible to disrupt, owing to the presence of several Endo-lysosomal damage-response mechanisms. Herein, we developed a lysosome-targeted photosensitizer (TLA), which possessed robust light stability, good bio-compatibility, and high photodynamic therapy (PDT) effect. Upon internalized by cancer cells, TLA was specifically accumulated in lysosome, and which would destroy the integrity of lysosomal membranes and inhibit protective autophagy upon exposure to light irradiation. Subsequently, the cancer cells were suffered from ferroptosis through triggering cell-intrinsic Fenton chemistry and mitochondrial dysfunction, which would release damage-associated molecular pattern molecules (DAMPs) to induce immunogenic cell death and remodel immunosuppressive tumor microenvironment. Notably, combined with PD-L1 antibody and TLA could greatly potentiate the immune response and exhibit highest anti-tumor effects. In summary, this novel lysosome-targeted photosensitizer could serve as a promising strategy for the treatment of colorectal cancer.

Calcium level and autophagy defect in GNE mutants of rare neuromuscular disorder

Rare genetic disorders are low in prevalence and hence there is little or no attention paid to them in the mainstream medical industry. One of the ultra-rare neuromuscular disorders, GNE myopathy is caused due to biallelic mutations in the bifunctional enzyme, GNE (UDP N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase). It catalyses the rate-limiting step in sialic acid biosynthesis. There are no effective treatments for GNE myopathy as the pathomechanism is poorly understood. Pathologically, the disease is characterized by the formation of rimmed vacuoles that contain aggregates of β-amyloid, tau, presenilin etc proteins in muscle biopsy samples. Accumulation of aggregated proteins in the cells may occur due to the failure of the regulated autophagy phenomenon. In the present study, we aim to understand the effect of GNE mutations on autophagy. The cytosolic calcium levels in GNE mutant cells were found to be altered in a GNE mutation-specific manner. The chaperone levels, such as HSP70 and PDI, as well as autophagic markers (LC3II/I ratios) were altered in the GNE mutant cells. Treatment with BAPTA-AM, calcium chelator, significantly restored cytosolic calcium levels in some GNE mutant cells as well as autophagic marker levels and autophagic punctae formation. The effect on the calcium signalling cascade involving CaMKKβ/AMPK/mTOR was studied in the GNE mutant cells. Our study provides insights into the role of calcium in autophagic vacuole formation in the cells with GNE mutations that will have significance towards understanding the pathomechanism of GNE Myopathy and drug target identification for the rare disease.

Asparagine prevents intestinal stem cell aging via the autophagy-lysosomal pathway

The age-associated decline in intestinal stem cell (ISC) function is a key factor in intestinal aging in organisms, resulting in impaired intestinal function and increased susceptibility to age-related diseases. Consequently, it is imperative to develop effective therapeutic strategies to prevent ISC aging and functional decline. In this study, we utilized an aging Drosophila model screening of amino acids and found that asparagine (Asn), a nonessential amino acid in vivo, exhibits its profound anti-aging properties on ISCs. Asn inhibits the hyperproliferation of aging ISCs in Drosophila, maintains intestinal homeostasis, and extends the lifespan of aging flies. Complementarily, Asn promotes the growth and branching of elderly murine intestinal organoids, indicating its anti-aging capacity to enhance ISC function. Mechanistic analyses have revealed that Asn exerts its effects via the activation of the autophagic signaling pathway. In summary, this study has preliminarily explored the potential supportive role of Asn in ameliorating intestinal aging, providing a foundation for further research into therapeutic interventions targeting age-related intestinal dysfunction.

Avian TRIM13 attenuates antiviral innate immunity by targeting MAVS for autophagic degradation

MAVS (mitochondrial antiviral signaling protein) is a crucial adaptor in antiviral innate immunity that must be tightly regulated to maintain immune homeostasis. In this study, we identified the duck Anas platyrhynchos domesticus TRIM13 (ApdTRIM13) as a novel negative regulator of duck MAVS (ApdMAVS) that mediates the antiviral innate immune response. Upon infection with RNA viruses, ApdTRIM13 expression increased, and it specifically binds to ApdMAVS through its TM domain, facilitating the degradation of ApdMAVS in a manner independent of E3 ligase activity. Furthermore, ApdTRIM13 recruits the autophagic cargo receptor duck SQSTM1 (ApdSQSTM1), which facilitates its interaction with ApdMAVS independent of ubiquitin signaling, and subsequently delivers ApdMAVS to phagophores for degradation. Depletion of ApdSQSTM1 reduces ApdTRIM13-mediated autophagic degradation of ApdMAVS, thereby enhancing the antiviral immune response. Collectively, our findings reveal a novel mechanism by which ApdTRIM13 regulates type I interferon production by targeting ApdMAVS for selective autophagic degradation mediated by ApdSQSTM1, providing insights into the crosstalk between selective autophagy and innate immune responses in avian species.Abbreviation: 3-MA: 3-methyladenine; ATG5: autophagy related 5; baf A1: bafilomycin A1; BECN1: beclin 1; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CARD: caspase recruitment domain; co-IP: co-immunoprecipitation; DEFs: duck embryonic fibroblasts; DTMUV: duck Tembusu virus; eGFP: enhanced green fluorescent protein; hpi: hours post infection; IFIH1/MDA5: interferon induced with helicase C domain 1; IFN: interferon; IKBKE/IKKε: inhibitor of nuclear factor kappa B kinase subunit epsilon; IP: immunoprecipitation; IRF7: interferon regulatory factor 7; ISRE: interferon-stimulated response element; mAb: monoclonal antibody; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAVS: mitochondrial antiviral signaling protein; MOI: multiplicity of infection; NBR1: NBR1 autophagy cargo receptor; NFKB: nuclear factor kappa B; pAb: polyclonal antibody; poly(I:C): Polyriboinosinic polyribocytidylic acid; RIGI: RNA sensor RIG-I; RLR: RIGI-like-receptor; SeV: sendai virus; siRNA: small interfering RNA; SQSTM1/p62: sequestosome 1; TAX1BP1: Tax1 binding protein 1; TBK1: TANK binding kinase 1; TCID50: 50% tissue culture infectious dose; TM: tansmembrane; TOLLIP: toll interacting protein; TRIM: tripartite motif containing; UBA: ubiquitin-associated domain; Ub: ubiquitin; VSV: vesicular stomatitis virus; WT: wild type.

Exploring melatonin's signalling pathways in the protection against age-related skin deterioration

Melatonin, renowned for regulating sleep-wake cycles, also exhibits notable anti-aging properties for the skin. Synthesized in the pineal gland and various tissues including the skin, melatonin's efficacy arises from its capacity to combat oxidative stress and shield the skin from ultraviolet (UV)-induced damage. Moreover, it curbs melanin production, thereby potentially ameliorating hyperpigmentation. The presence of melatonin receptors in diverse skin cell types and its documented ability to enhance skin tone, hydration, and texture upon topical administration underscores its promise as an anti-aging agent. Melatonin's protective effects likely emanate from its multifaceted characteristics, encompassing antioxidant, anti-inflammatory, and immunomodulatory functions, as well as its influence on collagen synthesis and mitochondrial activity. Chronic inflammation and oxidative stress initiate a detrimental feedback loop. Reactive oxygen species (ROS), notorious for damaging cellular structures, provoke immune responses by oxidizing vital molecules and activating signaling proteins. This triggers heightened expression of inflammatory genes, perpetuating the cycle. Such dysregulation significantly compromises the body's resilience against infections and other health adversities. This study embarks on an exploration of the fundamental signaling pathways implicated in skin aging. Furthermore, it delves into the therapeutic potential of melatonin and its anti-aging attributes within the realm of skin health.

Early Feeding in Critical Care - Where Are We Now?

The aim to avoid underfeeding has resulted in relative overfeeding of patients in the early phase of critical illness, worsening instead of improving outcomes. Negative randomised controlled trials have triggered mechanistic studies to investigate possible mechanisms explaining harm, allowing more scientific interpretation of many unexpected results during the last decades. Whereas individualized evidence-based approach to nutrition is still only rarely available, discussing and understanding of pathophysiological mechanisms should assist in decision-making in clinical practice. Further exploration of mechanisms of harm and benefit, as well as development of new technologies are needed to better plan future nutrition studies.

The role of autophagy in fibrosis: Mechanisms, progression and therapeutic potential (Review)

Various forms of tissue damage can lead to fibrosis, an abnormal reparative reaction. In the industrialized countries, 45% of deaths are attributable to fibrotic disorders. Autophagy is a highly preserved process. Lysosomes break down organelles and cytoplasmic components during autophagy. The cytoplasm is cleared of pathogens and dysfunctional organelles, and its constituent components are recycled. With the growing body of research on autophagy, it is becoming clear that autophagy and its associated mechanisms may have a role in the development of numerous fibrotic disorders. However, a comprehensive understanding of autophagy in fibrosis is still lacking and the progression of fibrotic disease has not yet been thoroughly investigated in relation to autophagy‑associated processes. The present review focused on the latest findings and most comprehensive understanding of macrophage autophagy, endoplasmic reticulum stress‑mediated autophagy and autophagy‑mediated endothelial‑to‑mesenchymal transition in the initiation, progression and treatment of fibrosis. The article also discusses treatment strategies for fibrotic diseases and highlights recent developments in autophagy‑targeted therapies.

Mitochondrial quality control disorder in neurodegenerative disorders: Potential and advantages of traditional Chinese medicines

Neurodegenerative disorders (NDDs) are prevalent chronic conditions characterized by progressive synaptic loss and pathological protein alterations. Increasing evidence suggested that mitochondrial quality control (MQC) serves as the key cellular process responsible for clearing misfolded proteins and impaired mitochondria. Herein, we provided a comprehensive analysis of the mechanisms through which MQC mediates the onset and progression of NDDs, emphasizing mitochondrial dynamic stability, the clearance of damaged mitochondria, and the generation of new mitochondria. In addition, traditional Chinese medicines (TCMs) and their active monomers targeting MQC in NDD treatment have been demonstrated. Consequently, we compiled the TCMs that show great potential in the treatment of NDDs by targeting MQC, aiming to offer novel insights and a scientific foundation for the use of MQC stabilizers in NDD prevention and treatment.

Multi-omics study reveals differential expression and phosphorylation of autophagy-related proteins in autism spectrum disorder

Our multi-omics study investigated the molecular mechanisms underlying autism spectrum disorder (ASD) using Shank3Δ4-22 and Cntnap2-/- mouse models. Through global- and phospho- proteomics of the mouse cortex, we focused on shared molecular changes and found that autophagy was particularly affected in both models. Global proteomics identified a small number of differentially expressed proteins that significantly impact postsynaptic components and synaptic function, including key pathways such as mTOR signaling. Phosphoproteomics revealed unique phosphorylation sites in autophagy-related proteins such as ULK2, RB1CC1, ATG16L1, and ATG9, suggesting that altered phosphorylation patterns contribute to impaired autophagic flux in ASD. SH-SY5Y cells with SHANK3 gene deletion showed elevated LC3-II and p62 levels, indicating autophagosome accumulation and autophagy initiation, while the reduced level of the lysosomal activity marker LAMP1 suggested impaired autophagosome-lysosome fusion. The study highlights the involvement of reactive nitrogen species and nitric oxide (NO) on autophagy disruption. Importantly, inhibition of neuronal NO synthase (nNOS) by 7-NI normalized autophagy markers levels in the SH-SY5Y cells and primary cultured neurons. We have previously shown that nNOS inhibition improved synaptic and behavioral phenotypes in Shank3Δ4-22 and Cntnap2-/- mouse models. Our multi-omics study reveals differential expression and phosphorylation of autophagy-related proteins in ASD but further investigation is needed to prove the full involvement of autophagy in ASD. Our study underscores the need for further examination into the functional consequences of the identified phosphorylation sites, which may offer potential novel therapeutic autophagy-related targets for ASD treatment.

Gene Expression Analysis of Autophagy Markers in Primary and Secondary Myelofibrosis

Background/Objectives: According to previous research, the process of autophagy in myeloid neoplasms has proven to be ambivalent depending on the type and stage of the disease. The aim of our work was to investigate the mechanism of autophagy in patients with primary and secondary myelofibrosis. Methods: Based on the RT-PCR method, we retrospectively analyzed the expression of Beclin-1 and LC3B-II in bone marrow cells of patients with primary and secondary myelofibrosis (74 participants) compared to the control group which had patients with lymphoma in a localized stage without bone marrow infiltration (11 participants). Results: There was no statistically significant difference in the expression of Beclin-1 and LC3B-II between patients with primary and secondary myelofibrosis and control participants. Among patients with primary myelofibrosis, higher expression of LC3B-II was statistically significantly associated with lower DIPSS. Higher Beclin-1 expression was statistically significantly associated with better patient survival. Conclusions: Our results suggest that the upregulation of autophagy genes may be associated with favorable prognosis and survival of patients with myelofibrosis.

Exosomes: an innovative therapeutic target for cerebral ischemia-reperfusion injury

Ischemic stroke is caused by artery stenosis or occlusion, which reduces blood flow and may cause brain damage. Treatment includes restoring blood supply; however, ischemia-reperfusion can still aggravate tissue injury. Reperfusion injury can increase levels of reactive oxygen species, exacerbate mitochondrial dysfunction, create excessive autophagy and ferroptosis, and cause inflammation during microglial infiltration. Cerebral ischemia-reperfusion injury (CIRI) is a key challenge in the treatment of ischemic stroke. Currently, thrombolysis (e.g., rt-PA therapy) and mechanical thrombectomy are the primary treatments, but their application is restricted by narrow therapeutic windows (<4.5 h) and risks of hemorrhagic complications. Exosomes reduce CIRI by regulating oxidative stress, mitochondrial autophagy, inflammatory responses, and glial cell polarization. In addition, their noncellular characteristics provide a safer alternative to stem cell therapy. This article reviews the research progress of exosomes in CIRI in recent years.

FVB But Not B6 Mice Carrying the Thr92Ala-Dio2 Polymorphism Have Impaired Thyroid Hormonogenesis and Goiter

The Thr92Ala-Dio2 polymorphism is prevalent worldwide, with about 50% of the population carrying at least 1 allele. The Ala92-Dio2 allele encodes a less active type 2 deiodinase enzyme and has been associated with neurodegenerative diseases, hypertension, and insulin resistance. To understand why its phenotypic effects are variable across different populations, in this study we examined the impact of genetic background on the Thr92Ala-Dio2 polymorphism. We focused on the thyroid gland of 2 genetically distant mouse strains, the C57BL/6J (B6) and the FVB/N (FVB). While the B6-Ala92-Dio2 mice have no meaningful phenotype, the FVB-Ala92-Dio2 exhibit a goiter (about 2.3-fold heavier thyroid) with an about 1.7-fold enlarged thyroid follicular area and impaired hormonogenesis with reduced thyroglobulin content of T4 and T3, 35% to 50% lower serum T4, and about 3-fold elevated serum TSH levels. Notably, the FVB-Ala92-Dio2 thyroid glands showed transcriptional evidence of endoplasmic reticulum stress, unfolded protein response, autophagy, and apoptosis. Female FVB-Ala92-Dio2 mice exhibited a more pronounced thyroid phenotype than males. These findings underscore the critical role of genetic background in modulating the phenotype outcomes of the Thr92Ala-Dio2 polymorphism and highlight its potential implications for understanding variable disease susceptibility in human populations.

HMBOX1 reverses autophagy mediated 5-fluorouracil resistance through promoting HACE1-induced ubiquitination and degradation of ATG5 in colorectal cancer

Chemotherapy remains the primary treatment for unresectable or advanced postoperative colorectal cancers. However, its effectiveness is compromised by chemoresistance, which adversely affects patient outcomes. Dysregulated macroautophagy/autophagy is a proposed mechanism behind this resistance, with ubiquitination playing a key regulatory role. In this study, we identify the transcription factor HMBOX1 (homeobox containing 1) as a critical regulator of chemoresistance in colorectal cancer. RNA sequencing revealed that HMBOX1 is downregulated in drug-resistant colorectal cancer cells and tissues, with its low expression linked to poor prognosis. An integrated analysis of genes associated with autophagy and 5-fluorouracil (5-FU) resistance was conducted, verified in the colorectal cancer tissues of patients by single-cell RNA sequencing and immunostaining. Mass-spectrometry-based proteomics and RNA sequencing were used to elucidate the underlying molecular mechanisms. Functionally, upregulation of HMBOX1 enhances the sensitivity of colorectal cancer cells to the first-line treatment with 5-FU by inhibiting autophagy. Mechanistically, HMBOX1 promotes the transcription of the E3 ubiquitin ligase HACE1, which in turn enhances ATG5 K63-ubiquitination and subsequent proteasome-mediated degradation. This results in decreased ATG5 levels, inhibiting autophagy and thus reducing 5-FU resistance in colorectal cancer cells both in vitro and in vivo. Furthermore, we confirm that HMBOX1 expression positively correlates with HACE1 expression and inversely correlates with autophagy levels in clinical colorectal cancer tissues. Our findings suggest that HMBOX1 downregulation drives 5-FU resistance through autophagy enhancement in colorectal cancer, highlighting HMBOX1 as a potential target for improving chemosensitivity and patient prognosis.Abbreviation: 3-MA: 3-methyladenine; 5-FU: 5-fluorouracil; ATG: autophagy related; CASP3: caspase 3; C-CASP3: cleaved caspase 3; C-PARP: cleaved PARP; CCK8: cell counting kit-8; ChIP: chromatin immunoprecipitation; CHX: cycloheximide; CNV: copy number variation; co-IP: co-immunoprecipitation; COAD: colorectal adenocarcinoma; CQ: chloroquine; CRC: colorectal cancer; CR: complete response; FHC: fetal human colon; GEO: Gene Expression Omnibus; HACE1: HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1; HMBOX1: homeobox containing 1; IHC: immunohistochemistry; LC-MS/MS: liquid chromatography-tandem mass spectrometry; mIHC: multiplexed immunohistochemistry; MUT: mutant; NC: negative control; OS: overall survival; PBS: phosphate-buffered saline; PD: progressive disease; PFA: paraformaldehyde; PFS: progression-free survival; PR: partial response; qPCR: quantitative polymerase chain reaction; RAPA: rapamycin; SD: stable disease; TCGA: The Cancer Genome Atlas; TEM: transmission electron microscopy; TF: translation factor; USP22: ubiquitin specific peptidase 22; WT: wild type.

Mechanism of LncRNA-MiRNA in Renal Intrinsic Cells of Diabetic Kidney Disease and Potential Therapeutic Direction

The occurrence of diabetic kidney disease (DKD), a critical microvascular issue in diabetes, is progressively on the rise. In recent years, long noncoding RNAs (lncRNAs) have garnered considerable attention as a novel and critical layer of biological regulation. Our knowledge regarding the roles and underlying mechanisms of lncRNAs in various diseases, including DKD, continues to evolve. Similarly, microRNAs (miRNAs), which are small noncoding RNAs, have been recognized as crucial contributors to cellular processes and disease pathogenesis. Emerging studies have highlighted the complex interactions between lncRNAs and miRNAs, particularly in the context of DKD, underscoring their importance in complex human diseases. Renal intrinsic cell damage is an important cause of inducing DKD. Persistent high glucose stimulation leads to remodeling of renal intrinsic cells and a cascade of pathological changes. This article aims to review recent literature on the lncRNAs-mediated regulation of miRNAs affecting renal intrinsic cells in DKD and to propose novel molecular-level therapeutic strategies for DKD. Through in-depth investigation of this dynamic molecular interaction, we can gain a profound understanding of the potential mechanisms underlying diabetic nephropathy, potentially identifying new targets for therapeutic intervention and paving the way for personalized and effective treatments.

PTBP2 promotes cell survival and autophagy in chronic myeloid leukemia by stabilizing BNIP3

Polypyrimidine tract binding protein 2 (PTBP2) regulates alternative splicing in neuronal, muscle, and Sertoli cells. PTBP2 and its paralog, PTBP1, which plays a role in B-cell development, was found to be expressed aberrantly in myeloid leukemia. Genetic ablation of Ptbp2 in the cells resulted in decreased cellular proliferation and repopulating ability, decreased reactive oxygen species (ROS), and altered mitochondrial morphology. RNA immunoprecipitation followed by sequencing (RIP-seq) and functional assays confirmed that PTBP2 binds to Bcl-2 Interacting Protein 3 (Bnip3)-3'UTR and stabilizes its expression. Our study also suggests that PTBP2 promotes autophagy, as evidenced by the low levels of LC3-II expression in Ptbp2-knockout cells treated with Bafilomycin A1. This effect was restored upon overexpression of Bnip3 in the knockout cells. Notably, when KCL22-NTC cells were subcutaneously injected into the flanks of mice, they gave rise to malignant tumors, unlike Ptbp2-KO-KCL22 cells. Also, transplantation of KCL22 cells through the tail vein in NOD/SCID mice resulted in higher cell engraftment and increased infiltration of malignant cells in the extramedullary organs. Our study underscores the role of PTBP2 in promoting cell proliferation and tumor formation while enhancing autophagy through Bnip3, thereby supporting the role of PTBP2 as an oncogene in CML.

MT1H inhibits the growth of gastric cancer by regulating SLC6A19/TTC39B/ADM2 and activating p53-dependent autophagy

Metallothioneins (MTs) are a class of cysteine-rich proteins that actively participate in the cellular defense against free radicals. However, owing to the high heterogeneity among different MTs, comprehensive investigations are needed to determine the biological activities and distribution patterns of each MT in different tissues. In the present study, ectopic expression of MT1H significantly inhibited the proliferation of gastric cancer cells. Mechanistically, MT1H was transported into the nucleus and regulated the expression of key genes involved in nutrient transportation and homeostasis, such as SLC6A19, TTC39B, and ADM2, and thereby activating the p53 and autophagy pathways. Additionally, survival analysis of data from the TCGA and other databases revealed that gastric cancer patients with high expression of MT1H had longer survival. Furthermore, MT1H was undetectable in most gastric cell lines, but its expression was increased upon treatment with dexamethasone (Dexa) and the metal ion zinc. Therefore, MT1H emerges as a valuable tumor suppressor, a biomarker for the prognosis, and a promising therapeutic target in gastric cancer patients.

Understanding the role of trehalose in interactions between Wolbachia and Aedes aegypti

Mosquito-borne diseases such as chikungunya, dengue, and Zika represent a major burden on global public health. To fight against these arboviruses, vector control strategies are a priority. One existing strategy is based on the use of an endosymbiotic bacterium, Wolbachia, which reduces the transmission of arboviruses by the mosquito Aedes aegypti via a pathogen blocking effect. Wolbachia in Ae. aegypti disrupts several pathways of the host's metabolism. Trehalose is a carbohydrate circulating mainly in insect hemolymph and plays a role in numerous mechanisms as energy source or stress recovery molecule and in chitin synthesis. This study explores the importance of trehalose in the interactions between Wolbachia and Ae. aegypti, and attempts to understand the pathogen blocking effect.

POLM inhibits porcine epidemic diarrhea virus replication by degrading multiple viral structural proteins

Porcine epidemic diarrhea, as a porcine epidemic diarrhea virus (PEDV)-induced infectious intestinal condition typified by diarrhea, emesis, dehydration, and anorexia, leads to death rates as high as 100% among suckling piglets. Given the existing commercial vaccines, it is essential to study host-virus interactions and formulate efficient anti-viral regimes. This study concerned a host factor POLM (a DNA polymerase family member) that exerts an anti-viral effect against PEDV proliferation. Our results indicated that POLM expression was increased following PEDV infection and was regulated by the transcription factor FOXA1. In addition, our findings indicated that POLM targeted and degraded PEDV structural proteins (N, S2, and M) by the autophagy pathway to inhibit PEDV proliferation. POLM could recruit the E3 ubiquitination ligase MARCH8 for N, S2, and M protein ubiquitination, which was subsequently recognized by p62, a cargo receptor, for translocation to the autophagic lysosome, therefore degrading the N, S2, and M proteins and preventing PEDV proliferation. In summary, we showed a novel therapeutic target for combating PEDV, i.e., using the POLM-MARCH8-p62-autophagosome pathway to degrade the PEDV N, S2, and M proteins.IMPORTANCEPEDV is a coronavirus that causes high mortality in piglets, which poses significant economic damage to swine farming. During PEDV infection, the host cells may promote the natural anti-viral immune response to suppress viral replication through a variety of potential host factors. In this study, we found upregulation of a host factor POLM by FOXA1 (a transcription factor) during PEDV infection. It was indicated that POLM could be a new anti-viral protein against the PEDV replication, which interacted with MARCH8 (an E3 ubiquitin ligase) and p62 (a cargo receptor) to facilitate the PEDV N, S2, and M protein degradation via the autophagy process. Apart from elucidating a previously unidentified anti-viral function of POLM, this study also provides a novel perspective for studying host anti-viral factors that act as regulators of anti-PEDV protein degrading pathways.

o8G-modified circPLCE1 inhibits lung cancer progression via chaperone-mediated autophagy

BACKGROUND

Lung cancer poses a serious threat to human health, but its molecular mechanisms remain unclear. Circular RNAs (circRNAs) are closely associated with tumour progression, and the important role of 8-oxoguanine (o8G) modification in regulating the fate of RNA has been gradually revealed. However, o8G modification of circRNAs has not been reported. We identified circPLCE1, which is significantly downregulated in lung cancer, and further investigated the o8G modification of circPLCE1 and the related mechanism in lung cancer progression.

METHODS

We identified differentially expressed circRNAs by RNA high-throughput sequencing and then conducted methylated RNA immunoprecipitation (MeRIP), immunofluorescence (IF) analysis, crosslinking immunoprecipitation (CLIP) and actinomycin D (ActD) assays to explore circPLCE1 o8G modification. The biological functions of circPLCE1 in vivo and in vitro were clarified via establishing a circPLCE1 silencing/overexpression system. Tagged RNA affinity purification (TRAP), RNA Immunoprecipitation (RIP) and coimmunoprecipitation (Co-IP) assays, and pSIN-PAmCherry-KFERQ-NE reporter gene were used to elucidate the molecular mechanism by which circPLCE1 inhibits lung cancer progression.

RESULTS

This study revealed that reactive oxygen species (ROS) can induce circPLCE1 o8G modification and that AUF1 can mediate a decrease in circPLCE1 stability. We found that circPLCE1 significantly inhibited lung cancer progression in vitro and in vivo and that its expression was associated with tumour stage and prognosis. The molecular mechanism was elucidated: circPLCE1 targets the HSC70 protein, increases its ubiquitination level, regulates ATG5-dependent macroautophagy via the chaperone-mediated autophagy (CMA) pathway, and ultimately inhibits lung cancer progression.

CONCLUSION

o8G-modified circPLCE1 inhibits lung cancer progression through CMA to inhibit macroautophagy and alter cell fate. This study provides not only a new theoretical basis for elucidating the molecular mechanism of lung cancer progression but also potential targets for lung cancer treatment.

Beyond expectations: investigating nilotinib's potential in attenuating neurodegeneration in alzheimer's disease

Neurodegenerative diseases, such as Alzheimer's disease (AD), pose a formidable global challenge. While therapeutic options are available, their limitations are significant, necessitating the development of innovative treatment approaches. Here, we highlight the importance of repurposing drugs and discuss the future of drug treatments for AD. We review the potential of tyrosine kinase inhibitors (TKI) for mitigating AD pathology and symptoms, as well as neurodegenerative processes more broadly. We focus on nilotinib, a selective BCR-ABL tyrosine kinase inhibitor, which has unique mechanisms of action involving the modulation of cell responses and removal of toxic proteins associated with AD pathogenesis. Encouraging studies have demonstrated its efficacy, calling for further investigation through clinical trials to assess its potential in various neurodegenerative conditions. However, despite these promising preclinical findings, no clinical studies have yet conclusively demonstrated its efficacy in treating AD. Considering the future directions in AD research, personalized medicine approaches hold promise by incorporating patient-specific factors, including sex and gender differences, to tailor nilotinib treatment for improved efficacy and safety profiles.

Deciphering significances of autophagy in the development and metabolism of adipose tissue

The mechanisms of adipose tissue activation and inactivation have been a hot topic of research in the last decade, from which countermeasures have been attempted to be found against obesity as well as other lipid metabolism-related diseases, such as type 2 diabetes mellitus and non-alcoholic fatty liver disease. Autophagy has been shown to be closely related to the regulation of adipocyte activity, which is involved in the whole process including white adipocyte differentiation/maturation and brown or beige adipocyte generation/activation. Dysregulation of autophagy in adipose tissue has been demonstrated to be associated with obesity. On this basis, we summarize the pathways and mechanisms of autophagy involved in the regulation of lipid metabolism and present a review of its pathophysiological roles in lipid metabolism-related diseases, in the hope of providing ideas for the treatment of these diseases.

Salidroside Derivative SHPL-49 Exerts Anti-Neuroinflammatory Effects by Modulating Excessive Autophagy in Microglia

The neuroinflammation triggered by cellular demise plays a pivotal role in ameliorating the injury associated with ischemic stroke, which represents a significant global burden of mortality and disability. The compound SHPL-49, a derivative of rhodioloside, was discovered by our research team and has previously demonstrated neuroprotective effects in rats with ischemic stroke. This study aimed to elucidate the underlying mechanisms of SHPL-49's protective effects. Preliminary investigations revealed that SHPL-49 effectively alleviates PMCAO-induced neuroinflammation. Further studies indicated that SHPL-49 downregulates the expression of the lysosomal protein LAMP-2 and reduces lysosomal activity, impeding the fusion of lysosomes and autophagosomes, thus inhibiting excessive autophagy and increasing the expression levels of the autophagy proteins LC3-II and P62. Furthermore, SHPL-49 effectively reverses the NF-κB nuclear translocation induced by the autophagy inducer rapamycin, significantly lowering the expression levels of the inflammatory factors IL-6, IL-1β, and iNOS. In a co-culture system of BV2 and PC12 cells, SHPL-49 enhanced PC12 cell viability by inhibiting excessive autophagy in BV2 cells and reducing the ratio of apoptotic proteins Bax and BCL-2. The overall findings suggest that SHPL-49 exerts its neuroprotective effects through the inhibition of excessive autophagy and the suppression of the NF-κB signaling pathway in microglia, thereby attenuating neuroinflammation.

Missense variants in GABAA receptor beta2 subunit disrupt receptor biogenesis and cause loss of function

Gamma-aminobutyric acid type A receptors (GABAARs) are the major inhibitory neurotransmitter-gated channel in the mammalian central nervous system. GABAARs function as heteropentamers, typically composed of two α1, two β2, and one γ2 subunits. Protein homeostasis between GABAAR folding, trafficking, assembly, and degradation is critical to ensure normal physiological functions. Variants in genes encoded for GABAARs lead to numerous neurological disorders, such as genetic epilepsy with or without neurodevelopmental delay. While these variants are associated with severe clinical presentations of epilepsy, the molecular mechanisms driving the disease remain to be elucidated. In this study, we focused on four missense epilepsy-associated variants (EAVs) in the GABRB2 gene: Q209F210delinsH (c. 627_629del), R240T (c. 719G>C), I246T (c. 737T>C), and I299S (c. 896T>G). HEK293T cells exogenously expressing these β2 variants exhibited significantly reduced GABA-induced peak chloride current, indicating their loss of function. However, the four β2 EAVs differed in the degree of proteostasis deficiencies, including increased ER retention, compromised assembly, decreased protein stability, and reduced trafficking and surface expression, with Q209F210delinsH and R240T variants leading to the most severe degradation. Collectively, these results indicate that these epilepsy-linked variants have debilitating effects on the early biogenesis of the β2 subunit, causing misfolding, aggregation, and rapid degradation before it can be assembled with other subunits and transported to the plasma membrane. Overall, our work offers crucial mechanistic insight into how specific β2 missense variants impact the proteostasis maintenance of GABAARs, which could facilitate the development of effective therapeutics for genetic epilepsy by targeting trafficking-deficient GABAAR variants.

Berberine and its derivatives: mechanisms of action in myocardial vascular endothelial injury - a review

Myocardial vascular endothelial injury serves as a crucial inducer of cardiovascular diseases. Mechanisms such as endoplasmic reticulum stress, apoptosis, inflammation, oxidative stress, autophagy, platelet dysfunction, and gut microbiota imbalance are intimately linked to this condition. Berberine and its derivatives have demonstrated potential in modulating these mechanisms. This article reviews the pathogenesis of endothelial injury in myocardial vessels, the pharmacological effects of berberine and its derivatives, particularly their interactions with targets implicated in vascular endothelial injury. Furthermore, it discusses clinical applications, methods to enhance bioavailability, and toxicity concerns, aiming to lay a foundation for the development of BBR as a therapeutic agent for cardiovascular diseases.

Evodiamine Promotes Autophagy and Alleviates Oxidative Stress in Dry Eye Disease Through the p53/mTOR Pathway

Purpose

This study aims to explore the therapeutic efficacy of evodiamine (EVO) in the treatment of dry eye disease (DED).

Methods

Mouse models of DED was developed using benzalkonium chloride eye drops and subcutaneous atropine injections. Corneal epithelial defects were assessed by fluorescein sodium staining, and tear secretion was measured with the phenol red thread test. For the in vitro model, human corneal epithelial cells were cultured in a sodium chloride-enriched medium. Phenotypic and mechanistic analyses were conducted using real-time quantitative PCR, Western blotting, flow cytometry, and immunofluorescence staining.

Results

The administration of EVO eye drops significantly enhanced tear secretion in mice, ameliorated ocular surface damage, decreased the expression of corneal inflammatory factors, and increased the density of conjunctival goblet cells. Furthermore, EVO reduced oxidative stress by promoting autophagy. Mechanistically, EVO-induced autophagy was mediated via the p53/mammalian target of rapamycin pathway.

Conclusions

These findings suggest that EVO is a potential therapeutic agent for the treatment of DED, with its beneficial effects attributed to the activation of autophagy through the p53/mammalian target of rapamycin pathway.

Nrf2 mediates mitochondrial and NADPH oxidase-derived ROS during mild heat stress at 40 °C

Hyperthermia is an adjuvant to chemotherapy and radiotherapy and sensitizes tumors to these treatments. However, repeated heat treatments result in acquisition of heat resistance (thermotolerance) in tumors. Thermotolerance is an adaptive survival response that appears to be mediated by upregulated cellular defenses. However, the mechanisms of activation remain unclear. When HeLa cells were exposed to mild heat shock at 40 °C for 3 h, levels of superoxide and peroxides increased. Cells were treated with mitochondrial antioxidant MitoQ and NADPH oxidase (NOX) inhibitor apocynin to characterize the contribution of these two sources to the total reactive oxygen species (ROS) pool. We found that both mitochondria and NOX are sources of ROS during mild heat shock at 40 °C. Heat-derived ROS are thought to activate the adaptive survival response at 40 °C. Nrf2, the master regulator of the cellular antioxidant response, is thought to play a pivotal role in establishing the adaptive survival response. Nrf2 was overexpressed or knocked down to assess its role. Moreover, Nrf2 levels correlate with the cellular redox state, and do so via scavenging of mitochondria- and NOX-derived ROS. Knockdown of Nrf2 markedly increased levels of ROS that were scavenged by either apocynin or MitoQ. Finally, critical defense proteins such as DJ-1 and PGAM5 seemed to require a two-key activation system mediated by Nrf2 and mitochondrial ROS. Our study characterized mitochondrial and NOX-derived ROS as being essential in activating cellular defenses alongside Nrf2 and underlines potential therapeutic targets that may contribute to the acquisition of thermotolerance.

Autophagy markers expression pattern in developing liver of the yotari (dab1-/-) mice and humans

Autophagy plays an important role in the physiology and pathology of the liver. Several negative autophagy regulators have been discovered, including epidermal growth factor receptor (EGFR), mediated by activation of the PI3K/Akt/mTOR signaling pathway. Disabled-1 (Dab1) is one of the mediating adaptor factors of PI3K/Akt/mTOR signaling pathways. We investigated the potential impact of Dab1 on autophagy-related markers (LC3B, LAMP2A, HSC70, and GRP78) in the developing liver by using a model of yotari mice and compared it with autophagy marker expression in human liver development. Mouse embryos were obtained at gestation days 13.5 and 15.5 (E13.5 and E15.5), and a total of 5 normal human conceptuses were obtained between gestation days 5 and 10. Histological sections were analyzed by immunohistochemistry. The highest expression of the early endosome-forming factor LC3B and the microautophagy factor LAMP2a was observed at the transition from embryonic to early fetal phase, whereas the expression of the chaperones HSC 70 and GRP78 was highest at embryonic phase. The expression patterns of three of these factors in mouse liver were different from those in human liver: the expression of LC3B was high at E13.5, that of HSC 70 at 15.5, whereas the expression of GRP78 did not change significantly. On the other hand, the expression pattern of LAMP2a was similar to that in human development and was higher at E15.5 than at E13.5. Moreover, knockout of Dab1 resulted in significantly lower expression of LC3B and LAMP2a in mouse embryo livers (at E13.5), indicating a possible role of Dab1 in regulating autophagy during embryonic development in the liver.

The Mechanisms and Implications of Cardiolipin in the Regulation of Cell Death

Cardiolipin (CL), an exclusive phospholipid, is predominantly found within the confines of the inner mitochondrial membrane, playing an indispensable role in the sustenance of mitochondrial operations and the regulation of cellular energy metabolism. The influence of CL on the pathways of cell death has garnered significant interest in recent scholarly discourse. This review delves into the multifaceted roles of CL across various modes of cell demise, encompassing apoptosis, autophagy, pyroptosis, ferroptosis, necrosis, and necroptosis. The discussion extends to the examination of CL's implications in a clinical context, particularly concerning cardiovascular maladies, neurological degeneration, and oncological conditions. Through an integrative analysis of contemporary research findings, the aim is to elucidate the intricate dynamics of CL's involvement in cell death phenomena. While acknowledging the inherent limitations and the hurdles faced by current research endeavors, the therapeutic potential of CL as a modulator of cell death pathways is nonetheless encouraging. Forthcoming investigations must surmount these obstacles, thereby uncovering the nuanced mechanisms and impacts of CL in the realm of cell death and associated pathologies, potentially paving the way for innovative clinical intervention strategies.

Dynamic regulation of autophagy during Semliki Forest virus infection of neuroblastoma cells

Autophagy can defend against infection by delivering viruses to lysosomes for degradation. Semliki Forest virus (SFV) is a positive-sense, single-stranded RNA virus of the alphavirus genus which has been used extensively as a model for arbovirus infection and neuronal encephalitis. Here, we show that autophagy is suppressed during the early hours of SFV infection of neurons. We also show that a switch between autophagy suppression and upregulation between the early and later stages was mediated through modulation of the mammalian target of rapamycin (mTOR) activity during infection. At later stages of infection, autophagosomes colocalize with SFV nonstructural proteins suggesting the formation of a platform for virus replication. Inhibition of mTOR by torin reduced infectious virus production and intracellular virus gene expression while improving cell survival during infection. The results suggest that autophagy is suppressed early during infection of neurons to increase cell survival and then upregulated at later times to facilitate replication. This biphasic regulation of autophagy seen for SFV may be important for other arboviruses, and knowledge about the regulation of autophagy by alphaviruses may be useful for the development of antiviral therapies.

N-acetyltransferase 10 impedes EZH2/H3K27me3/GABARAP axis mediated autophagy and facilitates lung cancer tumorigenesis through enhancing SGK2 mRNA acetylation

N4-acetylcytidine (ac4C) is a critical RNA modification implicated in cancer progression. Currently, N-acetyltransferase 10 (NAT10) is recognized as the sole "writer" protein responsible for ac4C modification. However, the study of NAT10 and ac4C modification in lung cancer remains sparse. In this study, we observed a significant upregulation of NAT10 expression in lung cancer, which is strongly correlated with poor prognostic outcomes. In vitro and in vivo experiments have demonstrated that NAT10 facilitates the proliferation, migration, and invasion of non-small cell lung cancer (NSCLC) cells while inhibiting autophagy flux. Mechanistically, NAT10 may enhance mRNA stability through ac4c modification at the 3' untranslated region (UTR) of SGK2 mRNA. Furthermore, SGK2 interacts with EZH2 and phosphorylates it at threonine 367, leading to increased protein stability of EZH2 and a reduction in its ubiquitination. Additionally, NAT10 impedes autophagy flux by preventing the fusion of autophagosomes with lysosomes and suppressing GABARAP transcription, which is regulated by EZH2-mediated H3K27me3. In summary, our study elucidates the biological significance and molecular mechanisms of the NAT10/SGK2/EZH2 axis in the pathogenesis of lung cancer, potentially providing novel prognostic markers and therapeutic targets for its treatment.

SGLT2 inhibitors: how do they affect the cardiac cells

The first sodium-glucose cotransporter-2 inhibitor (SGLT2I), canagliflozin, was approved by the U.S. Food and Drug Administration for the treatment of type 2 diabetes in 2013. Since then, other members of this drug class (such as dapagliflozin, empagliflozin, and ertugliflozin) have become widely used. Unlike classical antidiabetic agents, these drugs do not interfere with insulin secretion or action, but instead promote renal glucose excretion. Since their approval, many preclinical and clinical studies have been conducted to investigate the diverse effects of SGLT2Is. While originally introduced as antidiabetic agents, the SGLT2Is are now recognized as pillars in the treatment of heart failure and chronic kidney disease, in patients with or without diabetes. The beneficial cardiac effects of this class have been attributed to several mechanisms. Among these, SGLT2Is inhibit fibrosis, hypertrophy, apoptosis, inflammation, and oxidative stress. They regulate mitochondrial function and ion transport, and stimulate autophagy through several underlying mechanisms. This review details the potential effects of SGLT2Is on cardiac cells.

BTG3 inhibits porcine epidemic diarrhea virus replication by promoting viral S2 protein degradation through the autophagy and proteasome pathways

BTG3, which belongs to the BTG/Tob gene family, is involved in various physiological processes. Infection with porcine epidemic diarrhea virus (PEDV), an alphacoronavirus, is associated with high mortality rates among piglets, contributing to major economic losses. This study elucidated a novel mechanism through which BTG3 suppresses PEDV replication. Endogenous BTG3 protein expression was upregulated in PEDV-infected host cells. PEDV replication was suppressed upon BTG3 overexpression but enhanced upon BTG3 knockdown. Additionally, BTG3 inhibited viral proliferation by targeting and degrading the S2 subunit of the PEDV spike (S) protein through both autophagy and proteasome pathways. BTG3 interacted and co-localized with the S2 protein, promoting S2 protein degradation through the recruitment of the cargo receptor NDP52 and the E3 ubiquitin ligase MARCHF8. In summary, this study elucidated a novel antiviral mechanism in which the host BTG3 targeted the viral S2 protein to inhibit PEDV proliferation through autophagy and proteasome pathways. These findings indicate that BTG3 is a potential novel target for the prevention and control of PEDV.

SQSTM1/p62 from Litopenaeus vannamei is involved in the immune response to Vibrio infection

Sequestosome 1 (SQSTM1 or p62) has multiple functional domains, and it can not only be involved in autophagy process, but also defend against oxidative stress by invoking the Keap1/Nrf2 signaling pathway. However, the role of p62 in the response of Pacific whiteleg shrimp Litopenaeus vannamei to bacterial infection is still unclear. This study successfully identified p62 from L. vannamei (Lv-p62). The length of the open reading frame (ORF) of Lv-p62 is 1908 bp, which encoded 635 amino acids, and had Phox and Bem1p domain (PB1), Zinc-binding and ubiquitin-associated (UBA) domains. The expression level of Lv-p62 in the hepatopancreas of healthy L. vannamei is the highest, and it could be significantly induced under the stimulation of Vibrio harveyi. Besides, knocking down Lv-p62 by using RNA interference technology could reduce the expression levels of Nrf2 (nuclear factor erythroid 2-related factor 2), LC3 (microtubule-associated protein 1 light chain 3) and autophagy-related gene (ATG3, ATG5 and ATG12). Compared with the stimulation with V. harveyi alone, stimulation with V. harveyi after knocking down Lv-p62 could reduce the expression of antioxidant-, autophagy- and apoptosis-related genes in L. vannamei. Moreover, knocking down Lv-p62 could reduce the apoptosis signal of hepatopancreas and the abnormal tissue structure caused by V. harveyi. These results indicated that Lv-p62 is involved in the immune response to Vibrio infection in L. vannamei, which further enriched the regulatory function of p62 and its role in the innate immunity of shrimp.

Erythrocytes from gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) did not engage in phagocytosis

Phagocytosis is a fundamental innate immune process primarily executed by vertebrate leucocytes. Fish erythrocytes are involved in immune functions, although their role in phagocytosis remains poorly investigated. Consequently, this study aimed to examine the potential phagocytic mechanisms of fish erythrocytes. To this end, systemic blood erythrocytes were isolated from the teleost gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) and incubated for various times (20, 40, 60, 80, 100, and 120 min) with formalin-inactivated bacteria or heat-killed yeasts labelled with fluorescein isothiocyanate. Their putative phagocytic properties and respiratory burst activity were investigated. Our results did not indicate variations in the phagocytic ability or phagocytic capacity of erythrocytes of seabream or sea bass incubated with the bacteria, whereas no activity was detected in the case of incubation with yeast. Additionally, no respiratory burst activity was detected in the erythrocytes of either fish species under any of the experimental conditions tested. Using fluorescence microscopy, it was observed that erythrocytes could bind bacteria to their surface membranes. However, this attachment process was rarely seen with yeast cells. In contrast, examination of the fine structure of erythrocytes using transmission electron microscopy showed distinctive inward and outward folding (pseudopodia formation) and some cytoplasmic vesicles in both species. The results of our study indicate that erythrocytes from gilthead seabream and sea bass did not exhibit phagocytic capabilities when exposed to these specific target particles. Additional studies are necessary to gain more insights into how they contribute to the immune system of fish.

Unlocking the dual role of autophagy: A new strategy for treating lung cancer

Lung cancer exhibits the highest incidence and mortality rates among cancers globally, with a five-year overall survival rate alarmingly below 20%. Targeting autophagy, though a controversial therapeutic strategy, is extensively employed in clinical practice. Current research is actively pursuing various therapeutic strategies using small molecules to exploit the dual function of autophagy. Nevertheless, the pivotal question of enhancing or inhibiting autophagy in cancer therapy merits further attention. This review aims to provide a comprehensive overview of the mechanisms of autophagy in lung cancer. It also explores recent advances in targeting cytotoxic autophagy and inhibiting protective autophagy with small molecules to induce cell death in lung cancer cells. Notably, most autophagy-targeting drugs, primarily natural small molecules, have demonstrated that activating cytotoxic autophagy effectively induces cell death in lung cancer, as opposed to inhibiting protective autophagy. These insights contribute to identifying druggable targets and drug candidates for potential autophagy-related lung cancer therapies, offering promising approaches to combat this disease.

Tau degradation in Alzheimer's disease: Mechanisms and therapeutic opportunities

In Alzheimer's disease (AD), tau undergoes abnormal post-translational modifications and aggregations. Impaired intracellular degradation pathways further exacerbate the accumulation of pathological tau. A new strategy - targeted protein degradation - recently emerged as a modality in drug discovery where bifunctional molecules bring the target protein close to the degradation machinery to promote clearance. Since 2016, this strategy has been applied to tau pathologies and attracted broad interest in academia and the pharmaceutical industry. However, a systematic review of recent studies on tau degradation mechanisms is lacking. Here we review tau degradation mechanisms (the ubiquitin-proteasome system and the autophagy-lysosome pathway), their dysfunction in AD, and tau-targeted degraders, such as proteolysis-targeting chimeras and autophagy-targeting chimeras. We emphasize the need for a continuous exploration of tau degradation mechanisms and provide a future perspective for developing tau-targeted degraders, encouraging researchers to work on new treatment options for AD patients. HIGHLIGHTS: Post-translational modifications, aggregation, and mutations affect tau degradation. A vicious circle exists between impaired degradation pathways and tau pathologies. Ubiquitin plays an important role in complex degradation pathways. Tau-targeted degraders provide promising strategies for novel AD treatment.

Exploring the role and application of mitochondria in radiation therapy

Mitochondria are pivotal in cellular energy metabolism, the oxidative stress response and apoptosis. Recent research has focused on harnessing their functions to enhance the efficacy of radiation therapy (RT). This review focuses on the critical functions and applications of mitochondria in radiation therapy, including the targeting of mitochondrial metabolism and the modulation of mitochondria-mediated cell death and immune responses. While these strategies have demonstrated considerable potential in preclinical studies to improve radiotherapy outcomes, challenges remain, such as optimizing drug delivery systems, ensuring safety and overcoming resistance to therapy.