Calpain-mediated cleavage of Atg5 switches autophagy to apoptosis

Porcine cGAS-STING signalling induced apoptosis negatively regulates STING downstream IFN response and autophagy via different mechanisms

The innate immune cGAS-STING signalling pathway recognizes double-stranded DNA and induces the interferon (IFN) response, autophagy and apoptosis, exerting a broad antiviral effect. However, the mechanisms and interrelationship between STING induced downstream IFN, autophagy, and apoptosis in livestock have not been fully elucidated. Our previous study defined porcine STING (pSTING) induced IFN, autophagy and apoptosis, and showed that IFN does not affect autophagy and apoptosis, whereas autophagy inhibits both IFN and apoptosis, likely by promoting pSTING degradation. In this study, we further explored the underlying mechanism of pSTING induced apoptosis and the regulation of IFN and autophagy by apoptosis. First, pSTING induces endoplasmic reticulum (ER) stress and mitochondrial damage to activate caspases 9, 3, and 7, which drive intrinsic apoptosis. Second, pSTING triggered apoptosis inhibits the IFN response by activating caspase 7, which cleaves pIRF3 at the species specific D197/D198 site. Third, pSTING activated apoptotic caspases 9, 3, and 7 reduce the expression of ATG proteins, and cleave the ATG5-ATG12L1 complex, effectively inhibiting autophagy. Fourth, knockout of pSTING activated apoptosis heightens the IFN response and autophagy, while suppressing the replication of Herpes Simplex Virus type 1 (HSV-1), Vesicular Stomatitis Virus (VSV) and Pseudorabies Virus (PRV). This study sheds light on the molecular mechanisms of innate immunity in pigs.

Hijacking the autophagy-apoptosis crosstalk: African swine fever virus orchestrates immune evasion via host remodeling for viral pathogenesis

African swine fever (ASF) is an acute, highly fatal hemorrhagic disease of domestic and wild pigs caused by African swine fever virus (ASFV). ASFV, a large double-stranded DNA virus of the Asfarviridae family, is highly infectious and pathogenic. Through modulation of host apoptosis and autophagy pathways, the virus subverts innate immune surveillance to promote its replication and dissemination. Following ASFV infection, domestic pigs may exhibit 100 % morbidity and mortality rates with highly virulent strains, constituting a major threat to the global pork industry. Nowadays, ASF is listed as a notifiable terrestrial animal disease by the World Organisation for Animal Health (WOAH). Therefore, elucidating ASFV's pathogenic mechanisms, particularly its molecular regulation of apoptosis and autophagy, is crucial for developing effective ASF control and prevention strategies. This review comprehensively summarizes the pathogenic mechanisms of ASFV, with particular focus on the autophagy-apoptosis crosstalk and viral manipulation of these cellular processes. These insights not only improve our understanding of ASFV-mediated immune evasion mechanisms but also provide valuable references for developing ASF control strategies targeting apoptosis and autophagy pathways.

Mechanism of starvation induced autophagy and apoptosis in the midgut of silkworm, Bombyx mori, based on calcium homeostasis

Starvation can induce autophagy and apoptosis in intestinal cells. To elucidate the underlying mechanisms, we investigated autophagy and apoptosis in the midgut of the model insect, silkworm (Bombyx mori), focusing on calcium homeostasis. The results indicated that the body weight of silkworms decreased, along with damage to the morphology of their digestive tracts and midguts after starvation treatment. Additionally, mitochondrial swelling, autophagy and apoptosis were observable. Further investigation revealed that starvation upregulated the transcription of Ca2+ release channel-associated genes (e.g., BmIP3R, BmRyR) but suppressed the expression of Ca2+ efflux genes (BmPMCA), resulting in Ca2+ overload in midgut cells and subsequent upregulation of BmCalpain transcription. In addition, starvation increased the transcription of key autophagy genes (BmATG5, BmATG7, BmATG8) and the expression of the LC3-II protein. Upon prolonged starvation, the NtATG5 protein levels increased, a process that facilitated the transition from autophagy to apoptosis. These results indicate that Ca2+ overload activates the calpain-mediated apoptosis pathway and promotes apoptosis of midgut cells. The present study reveals the significant role that Ca2+ plays in the occurrence and transformation of autophagy and apoptosis induced by starvation treatment, thus providing a new research strategy for investigating the damage caused by starvation in biological organisms.

Role of Atg3, Atg5 and Atg12 in the crosstalk between apoptosis and autophagy in the posterior silk gland of Bombyx mori

Autophagy is a cellular mechanism that enhances cell survival in response to various stressors, including nutrient deprivation; however, it also plays a pivotal role in the regulation of programmed cell death. This study examined the effects of autophagy-related genes Atg3, Atg5 and Atg12 on apoptosis and autophagy during the degeneration of the posterior silk gland in Bombyx mori, employing RNA interference techniques. Apoptosis-specific markers and autophagic processes were evaluated in both control and treatment groups. The knockdown of all three genes resulted in a significant reduction in autophagy, modifications in the apoptosis process, aberrant expression of p53 and impaired lysosomal function. It was determined that Atg3 is involved in the regulation of intracellular mitochondrial homeostasis. Following the silencing of Atg5, evidence was obtained indicating the gene's role in regulating lysosomal pH. Notably, the loss of Atg3 and Atg5 was associated with an increase in apoptotic markers, whereas the silencing of Atg12 inhibited apoptosis. Elevated levels of the p53 transcription factor following gene silencing suggested a potential interaction between these genes and p53. Our findings further underscore the importance of autophagy-mediated cell death, involving Atg3, Atg5 and Atg12, in the proper progression of degeneration in the posterior silk gland. A comprehensive understanding of the molecular mechanisms that mediate the interaction between apoptosis and autophagy is essential for elucidating their roles in both physiological and pathological contexts.

Ormeloxifene induces mitochondrial fission-mediated pro-death autophagy in colon cancer cells

Ormeloxifene (ORM) is a nonsteroidal selective estrogen receptor modulator (SERM), developed by the CSIR-Central Drug Research Institute that is approved as an oral contraceptive. However, it has also shown promising anti-cancer activity, especially in breast cancer. Here, we have investigated the anti-cancer effect of ORM on colon cancer cells and show that its antiproliferative activity is mediated through mitochondrial fission and autophagy-associated cell death. We observed that ORM treatment led to an elevation in autophagy markers like LC3II, Beclin1, and Atg7. Autophagy induction and LC3II turnover were monitored by immunofluorescence staining and confocal microscopy. Transmission electron microscopy results confirmed the formation of autophagosomes and autophagolysosomes. Autophagic flux was confirmed by the increased expression of LC3II in cells co-treated with BafilomycinA1(autophagy inhibitor) and ORM. This was further corroborated using tandem mRFP-GFP-LC3 (tfLC3) transfection in DLD-1 cells. Interestingly, we observed that inhibition of autophagy reduced the apoptotic cell population, suggesting pro-death autophagy. ORM treatment caused notable ultrastructural alterations indicative of cellular stress. Notably, ORM triggered the generation of mitochondrial ROS, associated with increased levels of mitochondrial fission and a decrease in mitochondrial fusion proteins. Changes in mitochondrial dynamics were observed under the TEM, which included reduced mitochondrial size and increased mitochondrial number. Inhibition of mitochondrial fission resulted in enhanced cell survival and a concomitant decrease in the autophagic markers, implying that ORM-induced autophagy depends on mitochondrial fission. Taken together, our findings bring to light a novel mechanism where Ormeloxifene targets mitochondrial dynamics to promote autophagy-associated cell death in colon cancer cells.

Calpain1 inhibition enhances autophagy-lysosomal pathway and ameliorates tubulointerstitial fibrosis in Nephronophthisis

BACKGROUND

Nephronophthisis (NPH) is classified under the category of renal ciliopathies and is the most common genetic disease leading to renal failure in children. Early-onset and progressive renal tubulointerstitial fibrosis represents one of the most significant features, culminating in renal insufficiency. However, the molecular mechanism of tubulointerstitial fibrosis remains unclear. Previously, we constructed an NPH mouse model via CRISPR-Cas9. This mouse model demonstrated typical features of tubulointerstitial fibrosis. In this study, we aimed to explore the pathogenesis of tubulointerstitial fibrosis in NPH and identify early intervention targets in both the NPH models and patients.

METHODS

In this study, transcriptome changes in mouse kidneys were analyzed through RNA sequencing to explore the molecular mechanisms of renal tubulointerstitial fibrosis in NPH. We found an increased abundance of calpain1 in both the NPH models and patients. Pathway enrichment analysis indicated autophagy-lysosomal pathway was altered in the NPH models. Western blot, immunofluorescence or immunohistochemical staining were used to verify the expression of calpain1. We also detected autophagy activities in NPH models by lysotracker staining and transmission electron microscopy (TEM). Epithelial or mesenchymal-specific markers and Masson's trichrome staining were used to detect the status of tubulointerstitial fibrosis. Furthermore, NPH models were treated with a calpain1 inhibitor to explore the role of calpain1 in autophagy-lysosomal pathway and tubulointerstitial fibrosis.

RESULTS

The increased abundance of calpain1 impaired the autophagy-lysosomal pathway and induced tubulointerstitial fibrosis by promoting epithelial-to-mesenchymal transition. On the other hand, calpain1 inhibition could enhance the autophagy-lysosomal pathway and ameliorate the phenotypes of tubulointerstitial fibrosis in NPH models.

CONCLUSIONS

Calpain1-mediated autophagy-lysosomal pathway disorder may be an important cause of tubulointerstitial fibrosis in NPH. Calpain1 may have therapeutic implications for renal tubulointerstitial fibrosis.

Influenza A Virus Induces Autophagosome by Inhibiting LTCC/Calpain 2/LC3A Signaling to Promote Viral Replication

l-type voltage-gated calcium channels (LTCC), which are accountable for the influx of extracellular Ca2+, have been discovered to play a crucial regulatory role in the process of autophagy. However, the regulatory role of LTCC in autophagy process induced by influenza A virus (IAV) infection remains largely unknown. Here, we found that IAV (H1N1/PR8) induced autophagosome accumulation consistent with previous studies but blocked the fusion of autophagosomes with lysosomes. Meanwhile, viral infection led to a persistent decline of the cytoplasmic calcium signal in A549 cells. Interestingly, activation of LTCC partially restored the cytoplasmic calcium signal, impeded the formation of autophagosomes, and hindered the replication of IAV. Conversely, hindering LTCC or suppressing Cav1.3, the primary isoform of LTCC in A549 cells, significantly enhanced autophagosome formation and IAV replication. Mechanistically, calpain 2, a calcium-dependent cysteine protease, mediated the inhibition of LTCC/Cav1.3 on autophagosome formation and IAV replication by cleaving the carboxyl-terminal (112-118aa) of Microtubule-associated protein 1 light chain 3A(MAP1LC3A). Our findings reveal that IAV infection inhibits the LTCC/Cav1.3-calpain 2-LC3A axis to induce autophagosome formation, contributing to better understanding of viral infection process and providing potential target for combating IAV infection.

Dopamine Receptor D3 Induces Transient, mTORC1-Dependent Autophagy That Becomes Persistent, AMPK-Mediated, and Neuroprotective in Experimental Models of Huntington's Disease

Huntington disease's (HD) is a neurodegenerative disorder caused by the expansion of a polyglutamine region (PolyQ) within the huntingtin protein (HTT). Mutated huntingtin (mHTT) is cytotoxic, particularly for striatal medium spiny neurons (MSNs), whose degeneration is the hallmark of HD. Autophagy inducers currently available promote the clearance of toxic proteins. However, due to their low selectivity and the possibility that prolonged autophagy hampers essential processes in unaffected cells, researchers have questioned their benefits in neurodegenerative diseases. Since MSNs express dopamine receptors D2 (DRD2) and D3 (DRD3) and DRD2/DRD3 agonists may activate autophagy, here, we explored how healthy and mHTT-challenged cells respond to prolonged DRD2/DRD3 agonist treatment. Autophagy activation and its effects on mHTT/polyQ clearance were studied in R6/1 mice (a genetic model of HD), their wild-type littermates, and DRD2- and DRD3-HEK cells expressing a pathogenic (Q74) and a non-pathogenic (Q23) polyQ fragment of mHTT treated with the DRD2/DRD3 agonist pramipexole. Two forms of DRD3-mediated autophagy were found: a transient mTORC1-dependent in WT mice and Q23-DRD3-HEK cells and a persistent AMPK-ULK1-activated in R6/1 mice and Q74-DRD3-HEK cells. This also promoted a robust clearance of soluble mHTT/polyQ and neuroprotection in striatal neurons and DRD3-HEK cells. The findings indicate that DRD3-induced autophagy may be a safe, disease-modifying intervention in HD patients.

The role of autophagy in cancer: from molecular mechanism to therapeutic window

Autophagy is a cellular degradation process that plays a crucial role in maintaining metabolic homeostasis under conditions of stress or nutrient deprivation. This process involves sequestering, breaking down, and recycling intracellular components such as proteins, organelles, and cytoplasmic materials. Autophagy also serves as a mechanism for eliminating pathogens and engulfing apoptotic cells. In the absence of stress, baseline autophagy activity is essential for degrading damaged cellular components and recycling nutrients to maintain cellular vitality. The relationship between autophagy and cancer is well-established; however, the biphasic nature of autophagy, acting as either a tumor growth inhibitor or promoter, has raised concerns regarding the regulation of tumorigenesis without inadvertently activating harmful aspects of autophagy. Consequently, elucidating the mechanisms by which autophagy contributes to cancer pathogenesis and the factors determining its pro- or anti-tumor effects is vital for devising effective therapeutic strategies. Furthermore, precision medicine approaches that tailor interventions to individual patients may enhance the efficacy of autophagy-related cancer treatments. To this end, interventions aimed at modulating the fate of tumor cells by controlling or inducing autophagy substrates necessitate meticulous monitoring of these mediators' functions within the tumor microenvironment to make informed decisions regarding their activation or inactivation. This review provides an updated perspective on the roles of autophagy in cancer, and discusses the potential challenges associated with autophagy-related cancer treatment. The article also highlights currently available strategies and identifies questions that require further investigation in the future.

The inducible role of autophagy in cell death: emerging evidence and future perspectives

BACKGROUND

Autophagy is a lysosome-dependent degradation pathway for recycling intracellular materials and removing damaged organelles, and it is usually considered a prosurvival process in response to stress stimuli. However, increasing evidence suggests that autophagy can also drive cell death in a context-dependent manner. The bulk degradation of cell contents and the accumulation of autophagosomes are recognized as the mechanisms of cell death induced by autophagy alone. However, autophagy can also drive other forms of regulated cell death (RCD) whose mechanisms are not related to excessive autophagic vacuolization. Notably, few reviews address studies on the transformation from autophagy to RCD, and the underlying molecular mechanisms are still vague.

AIM OF REVIEW

This review aims to summarize the existing studies on autophagy-mediated RCD, to elucidate the mechanism by which autophagy initiates RCD, and to comprehensively understand the role of autophagy in determining cell fate.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review highlights the prodeath effect of autophagy, which is distinct from the generally perceived cytoprotective role, and its mechanisms are mainly associated with the selective degradation of proteins or organelles essential for cell survival and the direct involvement of the autophagy machinery in cell death. Additionally, this review highlights the need for better manipulation of autophagy activation or inhibition in different pathological contexts, depending on clinical purpose.

Atg5 in microglia regulates sex-specific effects on postnatal neurogenesis in Alzheimer's disease

Female Alzheimer's disease (AD) patients display greater cognitive deficits and worse AD pathology as compared to male AD patients. In this study, we found that conditional knockout (cKO) of Atg5 in female microglia failed to obtain disease-associated microglia (DAM) gene signatures in familiar AD mouse model (5xFAD). Next, we analyzed the maintenance and neurogenesis of neural stem cells (NSCs) in the hippocampus and subventricular zone (SVZ) from 5xFAD mice with Atg5 cKO. Our data indicated that Atg5 cKO reduced the NSC number in hippocampus of female but not male 5xFAD mice. However, in the SVZ, Atg5 cKO only impaired NSCs in male 5xFAD mice. Interestingly, female 5xFAD;Fip200 cKO mice and 5xFAD;Atg14 cKO mice did not show NSC defects. These autophagy genes cKO 5xFAD mice exhibited a higher neurogenesis activity in their SVZ. Together, our data indicate a sex-specific role for microglial Atg5 in postnatal neurogenesis in AD mice.

The Interplay Between Autophagy and Apoptosis in the Mechanisms of Action of Stilbenes in Cancer Cells

Plant-based stilbenes are low-molecular-weight polyphenolic compounds that exhibit anti-oxidant, anti-microbial, anti-fungal, anti-inflammatory, anti-diabetic, cardioprotective, neuroprotective, and anti-cancer activities. They are phytoalexins produced in diverse plant species in response to stress, such as fungal and bacterial infections or excessive UV irradiation. Plant-derived dietary products containing stilbenes are common components of the human diet. Stilbenes appear to be promising chemopreventive and chemotherapeutic agents. Accumulating evidence indicates that stilbenes are able to trigger both apoptotic and autophagic molecular pathways in many human cancer cell lines. Of note, the molecular crosstalk between autophagy and apoptosis under cellular stress conditions determines the cell fate. The autophagy and apoptosis relationship is complex and depends on the cellular context, e.g., cell type and cellular stress level. Apoptosis is a type of regulated cell death, whereas autophagy may act as a pro-survival or pro-death mechanism depending on the context. The interplay between autophagy and apoptosis may have an important impact on chemotherapy efficiency. This review focuses on the in vitro effects of stilbenes in different human cancer cell lines concerning the interplay between autophagy and apoptosis.

Autophagy in erectile dysfunction: focusing on apoptosis and fibrosis

ABSTRACT

In most types of erectile dysfunction, particularly in advanced stages, typical pathological features observed are reduced parenchymal cells coupled with increased tissue fibrosis. However, the current treatment methods have shown limited success in reversing these pathologic changes. Recent research has revealed that changes in autophagy levels, along with alterations in apoptosis and fibrosis-related proteins, are linked to the progression of erectile dysfunction, suggesting a significant association. Autophagy, known to significantly affect cell fate and tissue fibrosis, is currently being explored as a potential treatment modality for erectile dysfunction. However, these present studies are still in their nascent stage, and there are limited experimental data available. This review analyzes erectile dysfunction from a pathological perspective. It provides an in-depth overview of how autophagy is involved in the apoptotic processes of smooth muscle and endothelial cells and its role in the fibrotic processes occurring in the cavernosum. This study aimed to develop a theoretical framework for the potential effectiveness of autophagy in preventing and treating erectile dysfunction, thus encouraging further investigation among researchers in this area.

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

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

Insights into the different mechanisms of Autophagy and Apoptosis mediated by Morbilliviruses

Viruses are obligate intracellular parasites that have co-evolved with the host. During the course of evolution, viruses have acquired abilities to abrogate the host's immune responses by modulating the host proteins which play a pivotal role in various biological processes. One such process is the programmed cell death in virus-infected cells, which can occur via autophagy or apoptosis. Morbilliviruses are known to modulate both autophagy and apoptosis. Upon infecting a cell, the morbilliviruses can utilize autophagosomes as their nest and delay the host defense apoptotic response, and/or can promote apoptosis to escalate the virus dissemination. Moreover, there is an active interplay between these two pathways which eventually decides the fate of a virus-infected cell. Recent advances in our understanding of these processes provide a potential rationale to further explore morbilliviruses for therapeutic purposes.

Autophagy activation alleviates annulus fibrosus degeneration via the miR-2355-5p/mTOR pathway

BACKGROUND

Intervertebral disc degeneration disease (IVDD) is a major cause of disability and reduced work productivity worldwide. Annulus fibrosus degeneration is a key contributor to IVDD, yet its mechanisms remain poorly understood. Autophagy, a vital process for cellular homeostasis, involves the lysosomal degradation of cytoplasmic proteins and organelles. This study aimed to investigate the role of autophagy in IVDD using a hydrogen peroxide (H2O2)-induced model of rat annulus fibrosus cells (AFCs).

METHODS

AFCs were exposed to H2O2 to model oxidative stress-induced degeneration. Protein expression levels of collagen I, collagen II, MMP3, and MMP13 were quantified. GEO database analysis identified alterations in miR-2355-5p expression, and its regulatory role on the mTOR pathway and autophagy was assessed. Statistical tests were used to evaluate changes in protein expression and pathway activation.

RESULTS

H2O2 exposure reduced collagen I and collagen II expression to approximately 50% of baseline levels, while MMP3 and MMP13 expression increased twofold. Activation of autophagy restored collagen I and II expression and decreased MMP3 and MMP13 levels. GEO analysis revealed significant alterations in miR-2355-5p expression, confirming its role in regulating the mTOR pathway and autophagy.

CONCLUSIONS

Autophagy, mediated by the miR-2355-5p/mTOR pathway, plays a protective role in AFCs degeneration. These findings suggest a potential therapeutic target for mitigating IVDD progression.

TANGO2-related rhabdomyolysis symptoms are associated with abnormal autophagy functioning

Patients with pathogenic variants in the TANGO2 gene suffer from severe and recurrent rhabdomyolysis episodes precipitated by fasting. Autophagy functioning was analyzed in vitro, in primary skeletal myoblasts from TANGO2 patients, in basal and fasting conditions, and TANGO2 mutations were associated with reduced LC3-II levels upon starvation. In zebrafish larvae, tango2 inhibition induced locomotor defects which were exacerbated by exposure to atorvastatin, a compound known to cause rhabdomyolysis. Importantly, rhabdomyolysis features of tango2 knockdown were associated with autophagy and mitophagy defects in zebrafish. Calpeptin treatment was sufficient to rescue the locomotor properties thanks to its beneficial effect on autophagy functioning in zebrafish and to improve LC3-II levels in starved primary muscle cells of TANGO2 patients. Overall, we demonstrated that TANGO2 plays an important role in autophagy thus giving rise to new therapeutic perspectives in the prevention of RM life-threatening episodes.

Role of Autophagy in Type 2 Diabetes Mellitus: The Metabolic Clash

Type 2 diabetes mellitus (T2DM) is developed due to the development of insulin resistance (IR) and pancreatic β cell dysfunction with subsequent hyperglycaemia. Hyperglycaemia-induced oxidative stress and endoplasmic reticulum (ER) stress enhances inflammatory disorders, leading to further pancreatic β cell dysfunction. These changes trigger autophagy activation, which recycles cytoplasmic components and injured organelles. Autophagy regulates pancreatic β cell functions by different mechanisms. Though the exact role of autophagy in T2DM is not completely elucidated, that could be beneficial or detrimental. Therefore, this review aims to discuss the exact role of autophagy in the pathogenesis of T2DM.

Autophagy modulators in type 2 diabetes: A new perspective

Type 2 diabetes (T2D) is a chronic metabolic disorder caused by defective insulin signaling, insulin resistance, and impairment of insulin secretion. Autophagy is a conserved lysosomal-dependent catabolic cellular pathway involved in the pathogenesis of T2D and its complications. Basal autophagy regulates pancreatic β-cell function by enhancing insulin release and peripheral insulin sensitivity. Therefore, defective autophagy is associated with impairment of pancreatic β-cell function and the development of insulin rersistance (IR). However, over-activated autophagy increases apoptosis of pancreatic β-cells leading to pancreatic β-cell dysfunction. Hence, autophagy plays a double-edged sword role in T2D. Therefore, the use of autophagy modulators including inhibitors and activators may affect the pathogenesis of T2D. Hence, this review aims to clarify the potential role of autophagy inhibitors and activators in T2D.

Asiatic acid impedes NSCLC progression by inhibiting COX-2 and modulating PI3K signaling

Non-small cell lung cancer comprises up to 85% of lung cancer cases and has a poor prognosis. At present, there are still no effective treatments for this illness. Evidence suggests that the prostaglandin [cyclooxygenase-2 (COX-2)] and leukotriene [lipoxygenase-5 (5-LOX)] pathways are involved in lung cancer carcinogenesis. Therefore, novel agents that target COX-2 and 5-LOX may have therapeutic potential. In the present study, we examined the role of asiatic acid (AA), a triterpenoid saponin, in targeting the protein kinases responsible for lung cancer proliferation and mobility. The experimental data revealed that AA inhibited the growth of lung cancer cells (> 50%) and it significantly impeded the proliferation of lung cancer cells by inhibiting COX-2, which results in downregulation of the phosphotidyl inositol-3 kinase/protein kinase B/mammalian target of rapamycin signaling pathway, leading to an induction of cytotoxic autophagy-mediated apoptosis. Mechanistically, the expression of mitogen-activated protein kinase/extracellular signal-regulated kinase, hypoxia-inducible factor-1 and vascular endothelial growth factor is downregulated by AA, thereby reducing cell mobility and invasion. It also shows negative osmotic fragility on healthy human erythrocytes. It is concluded that AA may be a viable therapeutic drug for non-small cell lung cancer treatment, which opens new opportunities for synthesizing analogues.

Mechanism of programmed cell death in the posterior silk gland of the silkworm, Bombyx mori, during pupation based on Ca2+ homeostasis

The silkworm, Bombyx mori, is a complete metamorphosed economic insect, and the silk gland is a significant organ for silk protein synthesis and secretion. The silk gland completely degenerates during pupation, but the regulatory mechanism of programmed cell death (PCD) has not yet been understood. In the present study, we investigated the non-genetic pathway of 20E-induced PCD in the posterior silk gland (PSG) based on intracellular Ca2+ levels. Silk gland morphology and silk gland index indicated rapid degeneration of silk gland during metamorphosis from mature silkworm (MS) to pupal day 1 (P1), and Ca2+ levels within the PSG were found to peak during the pre-pupal day 1 (PP1) stage. Moreover, the results of autophagy and apoptosis levels within the PSG showed that autophagy was significantly increased in MS-PP1 periods, and significantly decreased in PP2 and P1 periods. Apoptosis was almost absent in MS-PP1 periods and significantly increased in PP2 and P1 periods. Additionally, western blotting results showed that autophagy preceded apoptosis, and the autophagy-promoting ATG5 was cleaved by calpain to the autophagy-inhibiting and apoptosis-promoting NtATG5 since PP1 period, while decreased autophagy was accompanied by increased apoptosis. Collectively, these findings suggest that Ca2+ is a key factor in the shift from autophagy to apoptosis.

Relationship Between Dietary Nutrient Intake and Autophagy-Related Genes in Obese Humans: A Narrative Review

Obesity is one of the world's major public health challenges. Its pathogenesis and comorbid metabolic disorders share common mechanisms, such as mitochondrial or endoplasmic reticulum dysfunction or oxidative stress, gut dysbiosis, chronic inflammation and altered autophagy. Numerous pro-autophagy dietary interventions are being investigated for their potential obesity-preventing or therapeutic effects. We summarize current data on the relationship between autophagy and obesity, and discuss various dietary interventions as regulators of autophagy-related genes in the prevention and ultimate treatment of obesity in humans, as available in scientific databases and published through July 2024. Lifestyle modifications (such as calorie restriction, intermittent fasting, physical exercise), including following a diet rich in flavonoids, antioxidants, specific fatty acids, specific amino acids and others, have shown a beneficial role in the induction of this process. The activation of autophagy through various nutritional interventions tends to elicit a consistent response, characterized by the induction of certain kinases (including AMPK, IKK, JNK1, TAK1, ULK1, and VPS34) or the suppression of others (like mTORC1), the deacetylation of proteins, and the alleviation of inhibitory interactions between BECN1 and members of the Bcl-2 family. Significant health/translational properties of many nutrients (nutraceuticals) can affect chronic disease risk through various mechanisms that include the activation or inhibition of autophagy. The role of nutritional intervention in the regulation of autophagy in obesity and its comorbidities is not yet clear, especially in obese individuals.

A crosstalk between autophagy and apoptosis in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe condition that devastatingly harms human health and poses a financial burden on families and society. Bcl-2 Associated X-protein (Bax) and B-cell lymphoma 2 (Bcl-2) are two classic apoptotic markers post-ICH. Beclin 1 offers a competitive architecture with that of Bax, both playing a vital role in autophagy. However, the interaction between Beclin 1 and Bcl-2/Bax has not been conjunctively analyzed. This review aims to examine the crosstalk between autophagy and apoptosis in ICH by focusing on the interaction and balance of Beclin 1, Bax, and Bcl-2. We also explored the therapeutic potential of Western conventional medicine and traditional Chinese medicine (TCM) in ICH via controlling the crosstalk between autophagy and apoptosis.

Targeting autophagy: polydatin's role in inducing cell death in AML

Acute myeloid leukemia (AML), a malignant disorder of the hematopoietic system, arises from leukemic stem cells (LSCs) and is the most prevalent form of blood cancer in adults. This study aimed to evaluate the therapeutic potential of polydatin (PD) in AML through ex vivo and in vivo studies, respectively. This study was prompted by PD's novel role in enhancing tumor apoptosis and modulating autophagy. In vitro studies were conducted using the PD-responsive AML cell line KASUMI-1 and found that PD was able to suppress cell proliferation and induce apoptosis by regulating the autophagy pathway. Subsequently, molecular docking was employed to predict the interaction between PD and Autophagy-related protein 5 (ATG5), a key regulator in the autophagy pathway. It was observed that PD inhibited the ubiquitination of ATG5 and enhanced its protein stability, leading to an increase in ATG5 protein levels and subsequent activation of the autophagy pathway (see in Abstract Graphed). The effectiveness and safety of PD in treating AML were confirmed through in vivo experiments using a mouse transplant tumor model, yielding definitive results. Collectively, these results suggest that PD is a promising candidate for the early therapeutic intervention of AML, with a strong potential for clinical application.

Cereblon mediates macrophage differentiation and microglial phagocytosis by regulating calpain protease activity

Autoimmune diseases encompass over 80 distinct types, affecting approximately 7.6-9.4 % of the population globally. The intricate interplay between genetic predispositions and environmental triggers complicates early diagnosis and intervention. Abnormal macrophage differentiation and proliferation have been identified as key contributors to the pathogenesis of these conditions, though the precise molecular pathways remain poorly understood. Recent studies suggest that cereblon (CRBN), a target for immunomodulatory drugs like thalidomide, lenalidomide, and pomalidomide, may offer therapeutic potential for autoimmune diseases such as systemic lupus erythematosus. In this study, quantitative proteomics revealed that CRBN downregulated the calpain regulatory subunit, calpain small subunit 1 (CAPNS1), in macrophages. Subsequent biochemical assays demonstrated that CRBN modulated calpain activity, impacting autophagy processes during macrophage differentiation and microglial phagocytosis. Histological evaluation of CRBN-deficient mice indicated a marked increase in microglial populations in the brain. These findings highlight potential therapeutic targets and present new avenues for the treatment of autoimmune diseases.

The dual role of ATG7: Regulation of autophagy and apoptosis in porcine ovarian follicular granulosa cells

The regulation of mammalian ovarian development involves the coordinated processes of autophagy and apoptosis. The autophagy-related gene ATG7 plays a pivotal role in mediating crosstalk between these pathways. Despite its recognized importance, the specific function of ATG7 in ovarian follicular granulosa cells remains poorly understood. This study aimed to explore the effects of ATG7 overexpression on apoptosis and autophagy in porcine ovarian follicular granulosa cells and thereby provide insights into the interplay between these fundamental cellular mechanisms. An ATG7 overexpression vector was introduced into cells, followed by assessment of cell proliferation using the CCK-8 assay, quantification of related gene expression via real-time quantitative PCR and western blotting, and evaluation of apoptosis using TUNEL staining. ATG7 exhibited a predominant cytoplasmic localization and additional nuclear expression in porcine ovarian follicular granulosa cells. The transfection efficiency of the vector was initially verified, indicating that its overexpression notably increased expression of ATG7 protein. Further investigations confirmed that overexpression of ATG7 inhibited cell proliferation, stimulated autophagy, and promoted apoptosis in these cells. In summary, overexpression of ATG7 influences the viability of porcine ovarian follicular granulosa cells by regulating the interplay between autophagy and apoptosis. This study not only broadens the understanding of functional regulation of autophagy and apoptosis by ATG7, but also sheds light on the intricate mechanisms governing ovarian follicular atresia.

Understanding the molecular regulatory mechanisms of autophagy in lung disease pathogenesis

Lung disease development involves multiple cellular processes, including inflammation, cell death, and proliferation. Research increasingly indicates that autophagy and its regulatory proteins can influence inflammation, programmed cell death, cell proliferation, and innate immune responses. Autophagy plays a vital role in the maintenance of homeostasis and the adaptation of eukaryotic cells to stress by enabling the chelation, transport, and degradation of subcellular components, including proteins and organelles. This process is essential for sustaining cellular balance and ensuring the health of the mitochondrial population. Recent studies have begun to explore the connection between autophagy and the development of different lung diseases. This article reviews the latest findings on the molecular regulatory mechanisms of autophagy in lung diseases, with an emphasis on potential targeted therapies for autophagy.

Basal State Calibration of a Chemical Reaction Network Model for Autophagy

The modulation of autophagy plays a dual role in tumor cells, with the potential to both promote and suppress tumor proliferation. In order to gain a deeper understanding of the nature of autophagy, we have developed a chemical reaction kinetic model of autophagy and apoptosis based on the mass action kinetic models that have been previously described in the literature. It is regrettable that the authors did not provide all of the information necessary to reconstruct their model, which made their simulation results irreproducible. In this study, based on an extensive literature review, we have identified concentrations for each species in the stress-free, homeostatic state. These ranges were randomly sampled to generate sets of initial concentrations, from which the simulations were run. In every case, abnormal behavior was observed, with apoptosis and autophagy being activated, even in the absence of stress. Consequently, the model failed to reproduce even the basal conditions. Detailed examination of the model revealed erroneous reactions, which were corrected. The influential kinetic parameters of the corrected model were identified and optimized using the Optima++ code. The model is now capable of simulating homeostatic states, and provides a suitable basis for further model development to describe cell response to various stresses.

Is Autophagy Targeting a Valid Adjuvant Strategy in Conjunction with Tyrosine Kinase Inhibitors?

Tyrosine kinase inhibitors (TKIs) represent a relatively large class of small-molecule inhibitors that compete with ATP for the catalytic binding site of tyrosine kinase proteins. While TKIs have demonstrated effectiveness in the treatment of multiple malignancies, including chronic myelogenous leukemia, gastrointestinal tumors, non-small cell lung cancers, and HER2-overexpressing breast cancers, as is almost always the case with anti-neoplastic agents, the development of resistance often imposes a limit on drug efficacy. One common survival response utilized by tumor cells to ensure their survival in response to different stressors, including anti-neoplastic drugs, is that of autophagy. The autophagic machinery in response to TKIs in multiple tumor models has largely been shown to be cytoprotective in nature, although there are a number of cases where autophagy has demonstrated a cytotoxic function. In this review, we provide an overview of the literature examining the role that autophagy plays in response to TKIs in different preclinical tumor model systems in an effort to determine whether autophagy suppression or modulation could be an effective adjuvant strategy to increase efficiency and/or overcome resistance to TKIs.

A comprehensive landscape analysis of autophagy in cancer development and drug resistance

Background

Autophagy plays important roles in cancer progression and therapeutic resistance, and the autophagy underlying the tumor pathogenesis and further mechanisms of chemoresistance emergence remains unknown.

Methods

In this study, via the single-sample gene set enrichment analysis (ssGSEA) method, an autophagy 45-gene list was identified to evaluate samples' autophagy activity, verified through six GEO datasets with a confirmed autophagy phenotype. It was further utilized to distinguish tumors into autophagy score-high and score-low subtypes, and analyze their transcriptome landscapes, including survival analysis, correlation analysis of autophagy- and resistance-related genes, biological functional enrichment, and immune- and hypoxia-related and genomic heterogeneity comparison, in TCGA pan-cancer datasets. Furthermore, we performed an analysis of autophagy status in breast cancer chemoresistance combined with multiple GEO datasets and in vitro experiments to validate the mechanisms of potential anticancer drugs for reversing chemoresistance, including CCK-8 cell viability assays, RT-qPCR, and immunofluorescence.

Results

The 45-gene list was used to identify autophagy score-high and score-low subtypes and further analyze their multi-dimensional features. We demonstrated that cancer autophagy status correlated with significantly different prognoses, molecular alterations, biological process activations, immunocyte infiltrations, hypoxia statuses, and specific mutational processes. The autophagy score-low subtype displayed a more favorable prognosis compared with the score-high subtype, associated with their immune-activated features, manifested as high immunocyte infiltration, including high CD8+T, Tfh, Treg, NK cells, and tumor-associated macrophages M1/M2. The autophagy score-low subtype also showed a high hypoxia score, and hypoxic tumors showed a significantly differential prognosis in different autophagy statuses. Therefore, "double-edged" cell fates triggered by autophagy might be closely correlated with the immune microenvironment and hypoxia induction. Results demonstrated that dysregulated autophagy was involved in many cancers and their therapeutic resistance and that the autophagy was induced by the resistance-reversing drug response, in five breast cancer GEO datasets and validated by in vitro experiments. In vitro, dihydroartemisinin and artesunate could reverse breast cancer doxorubicin resistance, through inducing autophagy via upregulating LC3B and ATG7.

Conclusion

Our study provided a comprehensive landscape of the autophagy-related molecular and tumor microenvironment patterns for cancer progression and resistance, and highlighted the promising potential of drug-induced autophagy in the activation of drug sensitivity and reversal of resistance.

Chemotherapeutic Potential of Chlorambucil-Platinum(IV) Prodrugs against Cisplatin-Resistant Colorectal Cancer Cells

Chlorambucil-platinum(IV) prodrugs exhibit multi-mechanistic chemotherapeutic activity with promising anticancer potential. The platinum(II) precursors of the prodrugs have been previously found to induce changes in the microtubule cytoskeleton, specifically actin and tubulin of HT29 colon cells, while chlorambucil alkylates the DNA. These prodrugs demonstrate significant anticancer activity in 2D cell and 3D spheroid viability assays. A notable production of reactive oxygen species has been observed in HT29 cells 72 h post treatment with prodrugs of this type, while the mitochondrial membrane potential was substantially reduced. The cellular uptake of the chlorambucil-platinum(IV) prodrugs, assessed by ICP-MS, confirmed that active transport was the primary uptake mechanism, with platinum localisation identified primarily in the cytoskeletal fraction. Apoptosis and necrosis were observed at 72 h of treatment as demonstrated by Annexin V-FITC/PI assay using flow cytometry. Immunofluorescence measured via confocal microscopy showed significant changes in actin and tubulin intensity and in architecture. Western blot analysis of intrinsic and extrinsic pathway apoptotic markers, microtubule cytoskeleton markers, cell proliferation markers, as well as autophagy markers were studied post 72 h of treatment. The proteomic profile was also studied with a total of 1859 HT29 proteins quantified by mass spectroscopy, with several dysregulated proteins. Network analysis revealed dysregulation in transcription, MAPK markers, microtubule-associated proteins and mitochondrial transport dysfunction. This study confirms that chlorambucil-platinum(IV) prodrugs are candidates with promising anticancer potential that act as multi-mechanistic chemotherapeutics.

Anticancer Effect of PtIIPHENSS, PtII5MESS, PtII56MESS and Their Platinum(IV)-Dihydroxy Derivatives against Triple-Negative Breast Cancer and Cisplatin-Resistant Colorectal Cancer

Development of resistance to cisplatin, oxaliplatin and carboplatin remains a challenge for their use as chemotherapies, particularly in breast and colorectal cancer. Here, we compare the anticancer effect of novel complexes [Pt(1,10-phenanthroline)(1S,2S-diaminocyclohexane)](NO3)2 (PtIIPHENSS), [Pt(5-methyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)](NO3)2 (PtII5MESS) and [Pt(5,6-dimethyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)](NO3)2 (PtII56MESS) and their platinum(IV)-dihydroxy derivatives with cisplatin. Complexes are greater than 11-fold more potent than cisplatin in both 2D and 3D cell line cultures with increased selectivity for cancer cells over genetically stable cells. ICP-MS studies showed cellular uptake occurred through an active transport mechanism with considerably altered platinum concentrations found in the cytoskeleton across all complexes after 24 h. Significant reactive oxygen species generation was observed, with reduced mitochondrial membrane potential at 72 h of treatment. Late apoptosis/necrosis was shown by Annexin V-FITC/PI flow cytometry assay, accompanied by increased sub-G0/G1 cells compared with untreated cells. An increase in S and G2+M cells was seen with all complexes. Treatment resulted in significant changes in actin and tubulin staining. Intrinsic and extrinsic apoptosis markers, MAPK/ERK and PI3K/AKT activation markers, together with autophagy markers showed significant activation of these pathways by Western blot. The proteomic profile investigated post-72 h of treatment identified 1597 MDA-MB-231 and 1859 HT29 proteins quantified by mass spectroscopy, with several differentially expressed proteins relative to no treatment. GO enrichment analysis revealed a statistically significant enrichment of RNA/DNA-associated proteins in both the cell lines and specific additional processes for individual drugs. This study shows that these novel agents function as multi-mechanistic chemotherapeutics, offering promising anticancer potential, and thereby supporting further research into their application as cancer therapeutics.

To eat or not to eat: a critical review on the role of autophagy in prostate carcinogenesis and prostate cancer therapeutics

Around 1 in 7 men will be diagnosed with prostate cancer during their lifetime. Many strides have been made in the understanding and treatment of this malignancy over the years, however, despite this; treatment resistance and disease progression remain major clinical concerns. Recent evidence indicate that autophagy can affect cancer formation, progression, and therapeutic resistance. Autophagy is an evolutionarily conserved process that can remove unnecessary or dysfunctional components of the cell as a response to metabolic or environmental stress. Due to the emerging importance of autophagy in cancer, targeting autophagy should be considered as a potential option in disease management. In this review, along with exploring the advances made on understanding the role of autophagy in prostate carcinogenesis and therapeutics, we will critically consider the conflicting evidence observed in the literature and suggest how to obtain stronger experimental evidence, as the application of current findings in clinical practice is presently not viable.

High glucose inhibits autophagy and promotes the proliferation and metastasis of colorectal cancer through the PI3K/AKT/mTOR pathway

BACKGROUND

Colorectal cancer (CRC) ranks among the most prevalent malignancies worldwide, characterized by its complex etiology and slow research progress. Diabetes, as an independent risk factor for CRC, has been widely certified. Consequently, this study centers on elucidating the intricacies of CRC cells initiation and progression within a high-glucose environment.

METHODS

A battery of assays was employed to assess the proliferation and metastasis of CRC cells cultured under varying glucose concentrations. Optimal glucose levels conducive to cells' proliferation and migration were identified. Western blot analyses were conducted to evaluate alterations in apoptosis, autophagy, and EMT-related proteins in CRC cells under high-glucose conditions. The expression of PI3K/AKT/mTOR pathway-associated proteins was assessed using western blot. The effect of high glucose on xenograft growth was investigated in vivo by MC38 cells, and changes in inflammatory factors (IL-4, IL-13, TNF-α, IL-5, and IL-12) were measured via serum ELISA.

RESULTS

Our experiments demonstrated that elevated glucose concentrations promoted both the proliferation and migration of CRC cells; the most favorable glucose dose is 20 mM. Western blot analyses revealed a decrease in apoptotic proteins, such as Bim, Bax, and caspase-3 with increasing glucose levels. Concurrently, the expression of EMT-related proteins, including N-cadherin, vimentin, ZEB1, and MMP9, increased. High-glucose cultured cells exhibited elevated levels of PI3K/AKT/mTOR pathway proteins. In the xenograft model, tumor cells stimulated by high glucose exhibited accelerated growth, larger tumor volumes, and heightened KI67 expression of immunohistochemistry. ELISA experiments revealed higher expression of IL-4 and IL-13 and lower expression of TNF-α and IL-5 in the serum of high-glucose-stimulated mice.

CONCLUSION

The most favorable dose and time for tumor cells proliferation and migration is 20 mM, 48 h. High glucose fosters CRC cell proliferation and migration while suppressing autophagy through the activation of the PI3K/AKT/mTOR pathway.

ATG5-regulated CCL2/MCP-1 production in myeloid cells selectively modulates anti-malarial CD4+ Th1 responses

Parasite-specific CD4+ Th1 cell responses are the predominant immune effector for controlling malaria infection; however, the underlying regulatory mechanisms remain largely unknown. This study demonstrated that ATG5 deficiency in myeloid cells can significantly inhibit the growth of rodent blood-stage malarial parasites by selectively enhancing parasite-specific CD4+ Th1 cell responses. This effect was independent of ATG5-mediated canonical and non-canonical autophagy. Mechanistically, ATG5 deficiency suppressed FAS-mediated apoptosis of LY6G- ITGAM/CD11b+ ADGRE1/F4/80- cells and subsequently increased CCL2/MCP-1 production in parasite-infected mice. LY6G- ITGAM+ ADGRE1- cell-derived CCL2 selectively interacted with CCR2 on CD4+ Th1 cells for their optimized responses through the JAK2-STAT4 pathway. The administration of recombinant CCL2 significantly promoted parasite-specific CD4+ Th1 responses and suppressed malaria infection. Conclusively, our study highlights the previously unrecognized role of ATG5 in modulating myeloid cells apoptosis and sequentially affecting CCL2 production, which selectively promotes CD4+ Th1 cell responses. Our findings provide new insights into the development of immune interventions and effective anti-malarial vaccines.Abbreviations: ATG5: autophagy related 5; CBA: cytometric bead array; CCL2/MCP-1: C-C motif chemokine ligand 2; IgG: immunoglobulin G; IL6: interleukin 6; IL10: interleukin 10; IL12: interleukin 12; MFI: mean fluorescence intensity; JAK2: Janus kinase 2; LAP: LC3-associated phagocytosis; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; pRBCs: parasitized red blood cells; RUBCN: RUN domain and cysteine-rich domain containing, Beclin 1-interacting protein; STAT4: signal transducer and activator of transcription 4; Th1: T helper 1 cell; Tfh: follicular helper cell; ULK1: unc-51 like kinase 1.

Sperm freezing damage: the role of regulated cell death

Substantial progress in research on sperm cryopreservation has occurred since the twentieth century, especially focusing on improving sperm freezing procedures and optimizing semen extenders. However, the cellular biological mechanisms of sperm freezing damage are still unclear, which greatly restricts the promotion and development of sperm cryopreservation. An essential component of sperm freezing damage is the occurrence of cell death. Considering the existence of multiple types of cell death pathways, this review discusses connections between characteristics of regulated cell death (e.g., apoptosis and ferroptosis), and accidental cell death (e.g., intracellular ice crystals) with sperm freezing damage and explores possible future research directions in this field.

The Role of Autophagy in Vascular Endothelial Cell Health and Physiology

Autophagy is a highly conserved cellular recycling process which enables eukaryotes to maintain both cellular and overall homeostasis through the catabolic breakdown of intracellular components or the selective degradation of damaged organelles. In recent years, the importance of autophagy in vascular endothelial cells (ECs) has been increasingly recognized, and numerous studies have linked the dysregulation of autophagy to the development of endothelial dysfunction and vascular disease. Here, we provide an overview of the molecular mechanisms underlying autophagy in ECs and our current understanding of the roles of autophagy in vascular biology and review the implications of dysregulated autophagy for vascular disease. Finally, we summarize the current state of the research on compounds to modulate autophagy in ECs and identify challenges for their translation into clinical use.

Unraveling the intriguing interplay: Exploring the role of lncRNAs in caspase-independent cell death

Cell death plays a crucial role in various physiological and pathological processes. Until recently, programmed cell death was mainly attributed to caspase-dependent apoptosis. However, emerging evidence suggests that caspase-independent cell death (CICD) mechanisms also contribute significantly to cellular demise. We and others have reported and functionally characterized numerous long noncoding RNAs (lncRNAs) that modulate caspase-dependent apoptotic pathways potentially in a pathway-dependent manner. However, the interplay between lncRNAs and CICD pathways has not been comprehensively documented. One major reason for this is that most CICD pathways have been recently discovered with some being partially characterized at the molecular level. In this review, we discuss the emerging evidence that implicates specific lncRNAs in the regulation and execution of CICD. We summarize the diverse mechanisms through which lncRNAs modulate different forms of CICD, including ferroptosis, necroptosis, cuproptosis, and others. Furthermore, we highlight the intricate regulatory networks involving lncRNAs, protein-coding genes, and signaling pathways that orchestrate CICD in health and disease. Understanding the molecular mechanisms and functional implications of lncRNAs in CICD may unravel novel therapeutic targets and diagnostic tools for various diseases, paving the way for innovative strategies in disease management and personalized medicine. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Molecular mechanisms in regulation of autophagy and apoptosis in view of epigenetic regulation of genes and involvement of liquid-liquid phase separation

Cellular physiology is critically regulated by multiple signaling nexuses, among which cell death mechanisms play crucial roles in controlling the homeostatic landscape at the tissue level within an organism. Apoptosis, also known as programmed cell death, can be induced by external and internal stimuli directing the cells to commit suicide in unfavourable conditions. In contrast, stress conditions like nutrient deprivation, infection and hypoxia trigger autophagy, which is lysosome-mediated processing of damaged cellular organelle for recycling of the degraded products, including amino acids. Apparently, apoptosis and autophagy both are catabolic and tumor-suppressive pathways; apoptosis is essential during development and cancer cell death, while autophagy promotes cell survival under stress. Moreover, autophagy plays dual role during cancer development and progression by facilitating the survival of cancer cells under stressed conditions and inducing death in extreme adversity. Despite having two different molecular mechanisms, both apoptosis and autophagy are interconnected by several crosslinking intermediates. Epigenetic modifications, such as DNA methylation, post-translational modification of histone tails, and miRNA play a pivotal role in regulating genes involved in both autophagy and apoptosis. Both autophagic and apoptotic genes can undergo various epigenetic modifications and promote or inhibit these processes under normal and cancerous conditions. Epigenetic modifiers are uniquely important in controlling the signaling pathways regulating autophagy and apoptosis. Therefore, these epigenetic modifiers of both autophagic and apoptotic genes can act as novel therapeutic targets against cancers. Additionally, liquid-liquid phase separation (LLPS) also modulates the aggregation of misfolded proteins and provokes autophagy in the cytosolic environment. This review deals with the molecular mechanisms of both autophagy and apoptosis including crosstalk between them; emphasizing epigenetic regulation, involvement of LLPS therein, and possible therapeutic approaches against cancers.

Natural products targeting autophagy and apoptosis in NSCLC: a novel therapeutic strategy

Lung cancer is the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) being the predominant type. The roles of autophagy and apoptosis in NSCLC present a dual and intricate nature. Additionally, autophagy and apoptosis interconnect through diverse crosstalk molecules. Owing to their multitargeting nature, safety, and efficacy, natural products have emerged as principal sources for NSCLC therapeutic candidates. This review begins with an exploration of the mechanisms of autophagy and apoptosis, proceeds to examine the crosstalk molecules between these processes, and outlines their implications and interactions in NSCLC. Finally, the paper reviews natural products that have been intensively studied against NSCLC targeting autophagy and apoptosis, and summarizes in detail the four most retrieved representative drugs. This paper clarifies good therapeutic effects of natural products in NSCLC by targeting autophagy and apoptosis and aims to promote greater consideration by researchers of natural products as candidates for anti-NSCLC drug discovery.

TRPM2-dependent autophagy inhibition exacerbates oxidative stress-induced CXCL16 secretion by keratinocytes in vitiligo

Vitiligo is a depigmented skin disease due to the destruction of melanocytes. Under oxidative stress, keratinocyte-derived chemokine C-X-C motif ligand 16 (CXCL16) plays a critical role in recruiting CD8+ T cells, which kill melanocytes. Autophagy serves as a protective cell survival mechanism and impairment of autophagy has been linked to increased secretion of the proinflammatory cytokines. However, the role of autophagy in the secretion of CXCL16 under oxidative stress has not been investigated. Herein, we initially found that autophagy was suppressed in both keratinocytes of vitiligo lesions and keratinocytes exposed to oxidative stress in vitro. Autophagy inhibition also promoted CXCL16 secretion. Furthermore, upregulated transient receptor potential cation channel subfamily M member 2 (TRPM2) functioned as an upstream oxidative stress sensor to inhibit autophagy. Moreover, TRPM2-mediated Ca2+ influx activated calpain to shear autophagy related 5 (Atg5) and Atg12-Atg5 conjugate formation was blocked to inhibit autophagy under oxidative stress. More importantly, Atg5 downregulation enhanced the binding of interferon regulatory factor 3 (IRF3) to the CXCL16 promoter region by activating Tank-binding kinase 1 (TBK1), thus promoting CXCL16 secretion. These findings suggested that TRPM2-restrained autophagy promotes CXCL16 secretion via the Atg5-TBK1-IRF3 signaling pathway under oxidative stress. Inhibition of TRPM2 may serve as a potential target for the treatment of vitiligo. © 2024 The Pathological Society of Great Britain and Ireland.

The nonautophagic functions of autophagy-related proteins

ABBREVIATIONS

ATG: autophagy related; BECN1: beclin 1; cAMP: cyclic adenosine monophosphate; dsDNA: double-stranded DNA; EMT: epithelial-mesenchymal transition; IFN: interferon; ISCs: intestinal stem cells; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK/JNK: mitogen-activated protein kinase/c-Jun N-terminal kinases; MTOR: mechanistic target of rapamycin kinase; STING1: stimulator of interferon response cGAMP interactor 1; UVRAG: UV radiation resistance associated; VPS: vacuolar protein sorting.

The interplay between autophagy and apoptosis: its implication in lung cancer and therapeutics

Maintaining cellular homeostasis relies on the interplay between apoptosis and autophagy, and disruption in either of these processes can contribute to the development of cancer. Autophagy can hinder the apoptotic process, and when autophagy is inhibited in such instances, it can enhance the rate of apoptosis. However, evidence suggests that excessive autophagy can also lead to apoptotic cell death. Also, excess autophagy can cause excessive digestion of cellular organelles, causing autophagic cell death. Targeting autophagy in non-small cell lung cancer (NSCLC), the most common form of lung cancer, can be very tricky due to the dual nature of autophagy. According to genetic analysis, various mutations in p53 and EGFR, G:C to A:T transversions seem responsible for the development of lung cancer in smokers and non-smokers. These events trigger cytoprotective autophagy or induce apoptotic cell death through different but interconnected signalling pathways. Lung cancer being the leading cause of death worldwide, calls for more attention to disease prognosis and new therapeutics in the market. However, molecules responsible for autophagy to apoptosis transition are yet to be studied elaborately. Also, the role of effector caspases during this shift needs to be elucidated in future. To comprehend how therapeutics operate through the modulation of autophagy and apoptosis and to target such pathways, it is crucial to emphasize these intricate connections. Many therapeutics discussed in this review targeting both apoptosis and autophagy have shown promising results in vitro and in vivo, however, few have crossed the hurdles of clinical trial. Nevertheless, the quest for safer and better efficacious agents is still alive, with the sole aim to develop novel cancer chemotherapeutic(s).

N-acetylcysteine and Hydroxychloroquine Ameliorate ADMA-Induced Fetal Growth Restriction in Mice via Regulating Oxidative Stress and Autophagy

Fetal growth restriction (FGR) seriously threatens perinatal health. The main cause of FGR is placental malperfusion, but the specific mechanism is still unclear, and there is no effective treatment for FGR. We constructed a FGR mouse model by adding exogenous asymmetric dimethylarginine (ADMA) through in vivo experiments and found that ADMA could cause placental dysplasia and induce the occurrence of FGR. Compared with the control group, reactive oxygen species (ROS) production in the placenta was increased in mice with FGR, and the expression of autophagy-related proteins p-AKT/AKT, p-mTOR/mTOR, and P62 was significantly decreased, while the expression of Beclin-1 and LC3-II was significantly increased in the FGR group. Furthermore, ADMA had a favorable effect in promoting the formation of autophagosomes. Hydroxychloroquine (HCQ) and N-acetylcysteine (NAC) improved ADMA-induced disorders of placental development and alleviated ADMA-induced FGR. This study found that ADMA could cause excessive autophagy of trophoblasts by increasing the level of oxidative stress, ultimately leading to the occurrence of FGR, and HCQ and NAC had therapeutic effects on ADMA-induced FGR.

Inhalation of ammonia promotes apoptosis and induces autophagy in hepatocytes via Bax/BCl-2 and m-TOR/ATG5/LC-3bII axes

Ammonia (NH3) is an irritating gas and atmospheric pollutant that endangers the health of humans and animals by stimulating respiratory tract's mucosa and causing liver damage. However, physiological role of ammonia gas in hepatotoxicity remains unclear. To investigate the hepatotoxic effects of inhaled ammonia gas, experiments were conducted using mouse model exposed to 100 ppm of ammonia gas for 21 days. The exposed mice exhibited signs of depression, emaciation, and reduced growth. This study revealed that inhalation of ammonia led to significant decrease in water (P < 0.0001) and food intake (P < 0.05), resulting in slower growth. Histopathological analysis showed that ammonia stress alters the microstructure of the liver by enlarging the gap between hepatic lobule and fibrosis. Moreover, ammonia-induced stress significantly reduces the expression of the anti-apoptotic protein BCl-2 (P < 0.001), while elevates the mRNA expression of the pro-apoptotic gene Bax (P < 0.001). Furthermore, ammonia inhalation significantly increases the protein expression of LC-3bII (P < 0.05) and the mRNA expression of autophagy-related gene 5 (ATG5) (P < 0.05) and p62 (P < 0.05) while remarkably decreases the mRNA expression of mammalian target of rapamycin (m-TOR) (P < 0.05). In conclusion, this study demonstrates that inhalation of ammonia gas causes liver damage and suggests autophagy happening via m-TOR/p62/LC-3bII and pro-apoptosis effect mediated by Bax/BCl-2 in the liver damage caused by ammonia inhalation. Our study provides a new perspective on ammonia-induced hepatotoxicity.

Role of ATG7-dependent non-autophagic pathway in angiogenesis

ATG7, one of the core proteins of autophagy, plays an important role in various biological processes, including the regulation of autophagy. While clear that autophagy drives angiogenesis, the role of ATG7 in angiogenesis remains less defined. Several studies have linked ATG7 with angiogenesis, which has long been underappreciated. The knockdown of ATG7 gene in cerebrovascular development leads to angiogenesis defects. In addition, specific knockout of ATG7 in endothelial cells results in abnormal development of neovascularization. Notably, the autophagy pathway is not necessary for ATG7 regulation of angiogenesis, while the ATG7-dependent non-autophagic pathway plays a critical role in the regulation of neovascularization. In order to gain a better understanding of the non-autophagic pathway-mediated biological functions of the autophagy-associated protein ATG7 and to bring attention to this expanding but understudied research area, this article reviews recent developments in the ATG7-dependent non-autophagic pathways regulating angiogenesis.

SIRT1 is a regulator of autophagy: Implications for the progression and treatment of myocardial ischemia-reperfusion

SIRT1 is a highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase. It is involved in the regulation of various pathophysiological processes, including cell proliferation, survival, differentiation, autophagy, and oxidative stress. Therapeutic activation of SIRT1 protects the heart and cardiomyocytes from pathology-related stress, particularly myocardial ischemia/reperfusion (I/R). Autophagy is an important metabolic pathway for cell survival during energy or nutrient deficiency, hypoxia, or oxidative stress. Autophagy is a double-edged sword in myocardial I/R injury. The activation of autophagy during the ischemic phase removes excess metabolic waste and helps ensure cardiomyocyte survival, whereas excessive autophagy during reperfusion depletes the cellular components and leads to autophagic cell death. Increasing research on I/R injury has indicated that SIRT1 is involved in the process of autophagy and regulates myocardial I/R. SIRT1 regulates autophagy through various pathways, such as the deacetylation of FOXOs, ATGs, and LC3. Recent studies have confirmed that SIRT1-mediated autophagy plays different roles at different stages of myocardial I/R injury. By targeting the mechanism of SIRT1-mediated autophagy at different stages of I/R injury, new small-molecule drugs, miRNA activators, or blockers can be developed. For example, resveratrol, sevoflurane, quercetin, and melatonin in the ischemic stage, coptisine, curcumin, berberine, and some miRNAs during reperfusion, were involved in regulating the SIRT1-autophagy axis, exerting a cardioprotective effect. Here, we summarize the possible mechanisms of autophagy regulation by SIRT1 in myocardial I/R injury and the related molecular drug applications to identify strategies for treating myocardial I/R injury.

Interleukin‑22 alleviates arginine‑induced pancreatic acinar cell injury via the regulation of intracellular vesicle transport system: Evidence from proteomic analysis

Acute pancreatitis (AP) is a severe inflammatory condition characterized by the activation of pancreatic enzymes within acinar cells, leading to tissue damage and inflammation. Interleukin (IL)-22 is a potential therapeutic agent for AP owing to its anti-inflammatory properties and ability to promote tissue repair. The present study evaluated the differentially expressed proteins in arginine-induced pancreatic acinar cell injury following treatment with IL-22, and the possible mechanisms involved in IL-22-mediated alleviation of AP. AR42J cells were stimulated using L-arginine to establish an acinar cell injury model in vitro and the damaged cells were subsequently treated with IL-22. The characteristics of the model and the potential therapeutic effects of IL-22 were examined by CCK-8 assay, flow cytometry, TUNEL assay, transmission electron microscopy and ELISA. Differentially expressed proteins in cells induced by arginine and treated with IL-22 were assessed using liquid chromatography-mass spectrometry. The identified proteins were further subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis to elucidate their functional roles. The present study demonstrated that arginine-stimulated cells showed significant pathological changes resembling those in AP, which were alleviated after IL-22 treatment. Proteomic analysis then demonstrated that in IL-22-treated cells, proteins related to the formation and fusion of autophagosomes with lysosomes were significantly downregulated, whereas endocytosis related proteins were enriched in the upregulated proteins. After IL-22 treatment, western blotting demonstrated reduced expression of autophagy-associated proteins. In conclusion, by inhibiting the formation and fusion of autophagosomes with lysosomes, IL-22 may have mitigated premature trypsinogen activation, subsequently minimizing acinar cell injury induced by L-arginine. This was accompanied by concurrent upregulation of endocytosis, which serves a pivotal role in sustaining regular cellular material transport and signal propagation. This research underscored the potential of IL-22 in mitigating arginine-induced AR42J injury, which could be valuable in refining treatment strategies for AP.

Targeted Inhibition of Hsp90 in Combination with Metformin Modulates Programmed Cell Death Pathways in A549 Lung Cancer Cells

The pathophysiology of lung cancer is dependent on the dysregulation in the apoptotic and autophagic pathways. The intricate link between apoptosis and autophagy through shared signaling pathways complicates our understanding of how lung cancer pathophysiology is regulated. As drug resistance is the primary reason behind treatment failure, it is crucial to understand how cancer cells may respond to different therapies and integrate crosstalk between apoptosis and autophagy in response to them, leading to cell death or survival. Thus, in this study, we have tried to evaluate the crosstalk between autophagy and apoptosis in A549 lung cancer cell line that could be modulated by employing a combination therapy of metformin (6 mM), an anti-diabetic drug, with gedunin (12 µM), an Hsp90 inhibitor, to provide insights into the development of new cancer therapeutics. Our results demonstrated that metformin and gedunin were cytotoxic to A549 lung cancer cells. Combination of metformin and gedunin generated ROS and promoted MMP loss and DNA damage. The combination further increased the expression of AMPKα1 and promoted the nuclear localization of AMPKα1/α2. The expression of Hsp90 was downregulated, further decreasing the expression of its clients, EGFR, PIK3CA, AKT1, and AKT3. Inhibition of the EGFR/PI3K/AKT pathway upregulated TP53 and inhibited autophagy. The combination was promoting nuclear localization of p53; however, some cytoplasmic signals were also detected. Further increase in the expression of caspase 9 and caspase 3 was observed. Thus, we concluded that the combination of metformin and gedunin upregulates apoptosis by inhibiting the EGFR/PI3K/AKT pathway and autophagy in A549 lung cancer cells.

The effect of electroacupuncture at ST25 on Parkinson's disease constipation through regulation of autophagy in the enteric nervous system

The effectiveness and safety of electroacupuncture (EA) for constipation have been confirmed by numerous clinical studies and experiments, and there are also studies on the efficacy of EA for Parkinson's disease (PD) motor symptoms. However, there are few researches on EA for PD constipation. Autophagy is thought to be involved in the mechanistic process of EA in the central nervous system (CNS) intervention in Parkinson's pathology. However, whether it has the same effect on the enteric nervous system (ENS) has not been elucidated. Therefore, we investigated whether EA at Tianshu (ST25) acupoint promotes the clearance of α-Syn and damaged mitochondria aggregated in the ENS in a model of rotenone-induced PD constipation. This study evaluated constipation symptoms by stool characteristics, excretion volume, and water content, and the expression levels of colonic ATG5, LC3II, and Parkin were detected by Western Blot (WB) and Real-Time Quantitative PCR (RT-qPCR). The relationship between the location of α-Syn and Parkin in the colonic ENS was observed by immunofluorescence (IF). The results showed that EA intervention significantly relieved the symptoms of rotenone-induced constipation in PD rats, reversed the rotenone-induced down-regulation of colonic ATG5, LC3II, and Parkin expression, and the positional relationship between colonic α-Syn and Parkin proved to be highly correlated. It is suggested that EA might be helpful in treating PD constipation by modulating Parkin-induced mitochondrial autophagy.