In this review, the regulatory mechanisms of autophagy were described, and its interaction with apoptosis was identified. The role of autophagy in embryogenesis, tooth development, and cell differentiation were also investigated. Autophagy is regulated by various autophagy-related genes and those related to stress response. Highly active autophagy occurrences have been reported during cell differentiation before implantation after fertilization. Autophagy is involved in energy generation and supplies nutrients during early birth, essential to compensate for their deficient supply from the placenta. The contribution of autophagy during tooth development, such as the shape of the crown and root formation, ivory, and homeostasis in cells, was also observed. Genes control autophagy, and studying the role of autophagy in cell differentiation and development was useful for understanding human aging, illness, and health. In the future, the role of specific mechanisms in the development and differentiation of autophagy may increase the understanding of the pathological mechanisms of disease and development processes and is expected to reduce the treatment of various diseases by modulating the autophagic phenomenon.

Bovine mammary epithelial (MAC-T) cells are commonly used to study mammary gland development and mastitis. Lipopolysaccharide is a major bacterial cell membrane component that can induce inflammation. Autophagy is an important regulatory mechanism participating in the elimination of invading pathogens. In this study, we evaluated the mechanism underlying bacterial mastitis and mammary cell death following lipopolysaccharide treatment. After 24 h of 50 μg/mL lipopolysaccharide treatment, a significant decrease in the proliferation rate of MAC-T cells was observed. However, no changes were observed upon treatment of MAC-T cells with 10 μg/mL of lipopolysaccharide for up to 48 h. Thus, upon lipopolysaccharide treatment, MAC-T cells exhibit dose-dependent effects of growth inhibition at 10 μg/mL and death at 50 μg/mL. Treatment of MAC-T cells with 50 μg/mL lipopolysaccharide also induced the expression of autophagy-related genes ATG3, ATG5, ATG10, ATG12, MAP1LC3B, GABARAP-L2, and BECN1. The autophagy-related LC3A/B protein was also expressed in a dose-dependent manner upon lipopolysaccharide treatment. Based on these results, we suggest that a high dose of bacterial infection induces mammary epithelial cell death related to autophagy signals.

Autophagy is an evolutionarily well-conserved cellular homeostasis program that responds to various cellular stresses and degrades unnecessary or harmful intracellular materials in lysosomes. Accumulating evidence has shown that autophagy dysfunction often results in various human pathophysiological conditions, including metabolic disorders, cancers, and neurodegenerative diseases. The discovery of an autophagy machinery protein network has revealed underlying molecular mechanisms of autophagy, and advances in the understanding of its regulatory mechanism have provided novel therapeutic targets for treating human diseases. Recently, reports have emerged on the involvement of autophagy in oral squamous cell carcinoma (OSCC). Although the role of autophagy in cancer therapy is controversial, the beneficial use of the induction of autophagic cell death in OSCC has drawn significant attention. In this review, the types of autophagy, mechanism of autophagosome biogenesis, and modulating molecules and therapeutic candidates affecting the induction of autophagic cell death in OSCC are briefly described.

Cudraxanthone D (CD) is a natural xanthone compound derived from the root barks of Cudrania tricuspidata . However, the biological functions of CD in human metabolism have been rarely reported until now. Autophagy is the self-degradation process related to cancer cell metastasis. Here, we elucidated the effects of CD on human oral squamous cell carcinoma (OSCC) cells’ metastatic ability. We confirmed that CD effectively decreased the proliferation and viability of SCC25 human OSCC cells in time- and dose-dependent manners. Also, the metastasis phenotype of the SCC25 cell (migration, invasion, and epithelial–mesenchymal transition [EMT]) was inhibited by CD. To further investigate the mechanism by which CD inhibited the metastatic capacity, we detected the relationship between EMT and autophagy in the SCC25 cells. The results revealed that CD inhibited the metastasis of the SCC25 cells by attenuating autophagy. Thus, our findings produced a potential novel agent for the treatment of human OSCC metastasis.

Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.

이 연구는 비만이 심장 조직에서 자가포식 관련 단백질 발현에 미치는 영향을 확인하기 위해 고지방 식이(20주)를 통해 비만을 유도한 후 8주간의 트레드밀 운동을 실시하고, 자가포식의 유도, 형성 그리고 자가포식포와 라이소좀 융합단계를 조절하는 단백질의 발현을 확인하였다. 실험동물(SD rat)은 20주 간의 고지방식이(탄수화물: 20%, 지방: 60%, 단백질: 20%)를 통해 비만을 유도하였으며, 8주간의 트레드 밀 운동(주 5일, 하루 30분, 5분; 8m/min, 5분; 11m/min, 20분; 14m/min)을 실시하였다. 집단 구분은 정상식이 비교군(n=10), 고지방식이 비교군(n=10), 고지방식이 운동군(n=10)으로 구분하였다. 8주간의 트레드밀 운동 실시 전과 후에 경구당부하검사를 실시하여 곡선하 면적(area under the curve; AUC)을 산출 하였으며, 공복시 인슐린 농도와 포도당 농도를 통해 인슐린 저항성 지표인 HOMA-IR과 체중 당 복부지 방량(abdominal visceral fat/Body weight; AVF/BW)를 산출하여 비교하였다. 또한 심장 조직에서 자가포식 관련 단백질을 분석하여 운동 트레이닝의 효과를 검증하였다. 장기간의 고지방식이를 통해 HFD-CON 그룹에서는 비만이 유도되었으며, ND-CON 그룹에 비해 체중, AUC, HOMA-IR, AVF/BW가 증가되는 것으로 나타났다. 하지만 8주간의 트레드밀 운동을 실시한 HFD-TE 그룹에서는 AUC, HOMA-IR, AVF/BW가 개선되는 것으로 나타났다. 체중의 경우, 감소되는 경향은 있었지만, 통계적으로 유의한 차이는 없었다. 자가포식 유도에 관여하는 mTOR와 AMPK는 비만상황에서 모두 감소되었지만, 운동을 통해 증가되는 것으로 나타났다. 자가포식 형성에 관련된 Beclin-1, BNIP3, ATG-7, p62, LC3는 비만상황에서 모두 증가하는 것으로 나타났으며, 운동을 통해 감소되는 것으로 나타났다. 자기포식포와 라이소좀 융합단계 조절하는 Cathepsin L과 LAMP2는 비만상황에서 모두 감소되었으며, 운동을 통해 증가하는 것으로 나타났다. 트레드밀 운동과 같은 신체활동은 대사성 질환에서 나타나는 병리학적 현상을 개선하고 자가포식 과정을 정상적으로 유도하는 것으로 나타났다. 따라서 트레드밀 운동이 심장 관련 질환의 예방 및 치료에 있어 일차적으로 고려해야할 필요성이 있다고 제안한다.

Autophagy is recently receiving the spotlight as the development strategy for promising anticancer drugs. In particular, the majority of anticancer drugs originating from natural products are known to induce autophagy. Saururus chinensis has been used for treating various inflammatory diseases. Recent research has revealed that the extract of Saururus chinensis possess cytotoxicity for various types of human cancer cells. However, the exact action mechanism of Saururus chinensis extract for oral squamous cell carcinoma (OSCC) has not been studied yet. Therefore, the authors of this research aim to study the effect of methanol extract of S. chinensis (MESC) on OSCC cells. To observe the cell proliferation inhibitory effect of MESC on HSC3 cells, the authors conducted the trypan blue exclusion assay. Also, the action mechanism of MESC was studied by conducting the cell cycle analysis, acidic vesicular organelle (AVO) staining and flow cytometry analysis, monodansylcadaverine (MDC) staining, propidium iodide staining, and Western blotting on MESC-treated HSC3 cells. When HSC3 cells were treated in MESC, the cell proliferation was suppressed in time-dependent and dose-dependent manners. Also, the number of sub-G1 arrested cells increased in a dose-dependent manner. MDC punctate and AVO puncta significantly increased respectively. Western blot analysis demonstrated the expression of autophagy-related proteins increased, but apoptotic proteins were not observed. Also, the pAkt protein was reduced, while the p-p38 protein and pERK protein increased. According to our results, MESC induced autophagy and accompanied changes in the cell cycle in HSC3 cells. Also, the alteration in Akt, ERK, and p38 pathways were confirmed. This result suggested the possibility of MESC as the new promising adjuvant for treating OSCC patients.

Here, we evaluated the mode of programmed cell death during porcine oocyte maturation by comparing the two major pathways associated with programmed cell death, apoptosis (type I), and autophagy (type II). We investigated the expression and localization of major genes involved in autophagy and apoptosis at mRNA and protein levels. Furthermore, the effect of hormonal stimulation on autophagy and apoptosis was analyzed. We found that the activity of autophagy-associated genes was increased in the cumulus-oocyte complexes (COCs) following follicle-stimulating hormone (FSH) treatment, while the addition of luteinizing hormone (LH) reversed this effect. The expression of proteins associated with autophagy was the highest in FSH-treated COCs. On the other hand, caspase-3 protein level was maximum in COCs cultured with LH. The treatment with rapamycin resulted in the effect similar to that observed with FSH treatment and increased autophagy activity. Thus, hormonal stimulation of pig oocytes resulted in distinct patterns of maturation. The high-quality oocytes majorly relied on the type II pathway (autophagy), while the type I pathway (apoptosis) was more prominent among poor-quality oocytes. Further investigation of this distinction may allow the development of techniques to produce high-quality oocytes in porcine in vitro fertilization.

Natural products are vastly utilized as a source of chemotherapeutic agents for human cancers. Kochia scopraia is traditionally used for the cure of urological and dermatological diseases. Recently, methanol extract of Kochia scoparia (MEKS) has been shown to have anti-cancer activity to various human cancers. However, there is no report demonstrating the anti-cancer activity of MEKS in human mucoepidermoid carcinoma (MEC) cells. In this study, the authors studied the effects of MEKS on the cell proliferation and underlying mechanism in YD15 human MEC cells. MEKS decreased YD15 cell proliferation proven by trypan blue exclusion assay and induced apoptosis, evidenced by cell cycle analysis and western blotting. Autophagy induction by MEKS was verified by western blotting. In addition, MEKS regulated the expression of phosphorylated Akt, phosphorylated p38 and Nrf2 protein. This results can imply that MEKS might be a potential candidate for the treatment of human MEC cells.

Mitochondrial and mitochondrial DNA (mtDNA) is maternally inherited in humans and most animals. The degradation of sperm-borne mitochondria after fertilization assures normal preimplantation embryo development and may prevent mitochondrial diseases derived from heteroplasmy. Although it has been known that ubiquitin-proteasome system (UPS) is the major degradation pathway of post-fertilization sperm mitochondria in mammals, it is unclear how the UPS, which is able to get rid of single protein molecule at a time, can eliminate whole sperm mitochondrial organelle. We considered that the autophagy receptors [sequestosome 1(SQSTM1), microtubule-associated protein 1 light chain 3 (LC3), and gamma-aminobutyric acid receptor-associated protein (GABARAP)] and the non-traditional mitophagy pathways involving UPS and the ubiquitin-binding protein dislocase, valosin-containing protein (VCP) may act independently or in concert during post-fertilization sperm mitophagy. We found that the association of SQSTM1 with sperm mitochondria was displayed in both pig and rhesus monkey zygotes after fertilization. Sperm mitochondrial proteins [mitochondrial trifunctional enzyme subunit alpha (HADHA), mitochondrial aconitase 2 (ACO2), and mitochondrial ATP synthase H+ transporting F1 complex β-subunit (ATP5B)] co-purified with the synthetic, SQSTM1-derived, ubiquitin-binding UBA domain were identified. Also, the accumulation of GABARAP-positive protein aggregates was observed around sperm mitochondrial sheaths in fertilized oocytes, which reflects autophagosome formation. Furthermore, the inhibition of VCP delayed the process of sperm mitophagy and completely blocked it when embryos were co-injected with autophagy-targeting antibodies, such as anti-SQSTM1 and/or anti-GABARAP. Thus, both SQSTM1-dependent autophagy pathway and VCP-mediated proteasomal proteolysis facilitate post-fertilization sperm mitophagy in mammals. This explains how the proteolytic pathway can coordinate autophagy pathway to degrade the sperm mitochondrial sheath inside the fertilized oocyte.

Autophagy is an important self-eating process to eliminate damaged or unused organelles. We identified nine autophagy-related genes (Atg) including AaAtg-1, -3, -4b, -4d, -5, -6, -8, -12 and -13 from the Asian tiger mosquito, Aedes albopictus. Developmental expression patterns indicate that mRNA levels of AaAtg-1, -3, -4b, -4d, -5, -6, -12 and -13 were highly expressed in egg, whereas expression of AaAtg8 was high in 1stand3rdinstarlarvalstages. TissuespecificexpressionofthesegenesindicatesthatAaAtg1 was highly expressed in thorax and midgut in blood-fed adult female mosquitoes (BF), and head and thorax in sugar fed adult female mosquitoes (SF). Transcript level of AaAtg3 was high in thorax in BF, but head, thorax and Malpighian tubules in SF. AaAtg4b, -4d mRNA levels were significantly high in Malpighian tubules in BF, and head in SF, respectively. AaAtg-5 and -6 transcripts were highly expressed in head in BF, and expression of AaAtg-8 was high in Malpighian tubules in BF. Levels of AaAtg-12 and -13 mRNAs were significantly high in head and midgut in BF. Induction patterns of AaAtg genes against pathogens showed that AaAtg-1, -3, -4b, -8, -12 and -13 were strongly induced at 6 h-post injection of S. aureus, and mRNA levels of AaAtg-1, -3 and -13 were significantly induced by E. coli challenge after 3 h-post injection in SF abdominal carcass. In SF midgut, AaAtg-1, -3, -4b, -4d, -5, -6, -12 and -13 transcripts were drastically induced at 9 h-injection of E. coli and S. aureus, while expression of AaAtg-8 was highly induced by S. aureus and C. albicans at 9 h-post injection. Each AaAtg gene was slightly induced by E. coli, S. aureus or C. albicans at different time points in abdominal carcass in BF. Interestingly, AaAtg-8 was not induced by microbial challenge. While eight other Atg genes except AaAtg-8 were highly influenced by S. aureus at 6 and 9 h-post injection, E. coli at 3 h-post-treatment, and 3, 6, and 9 h-post inoculation. In the future, we will characterize the functional roles of autophagy during mosquito-microbes interaction.

α-solanine is toxic to human health by disturbing digestive and central nervous systems. However, little information has been focused on investigated with respect to α-solanine influence in mammal oocyte maturation and quality. In this study, we investigated the effects of α-solanine on oocyte maturation, quality and possible molecular mechanisms in a pig model. Porcine Cumulus-oocyte complexes (COCs) were treated with increasing concentration (0, 1, 10, 20, 50 μM) of α-solanine subjected to further in vitro maturation culture. The result showed that α-solanine significantly inhibited cumulus cells expansion and increased oocyte death rates when the concentration of α-solanine more than 10 μM. After cell cycle and cytoskeleton analysis, the results showed that α-solanine (10 μM) disturbed meiotic resumption, increased abnormal spindle formation and cortical granules (CGs) distribution rates when compared with the untreated group. α-solanine (10 μM) triggered autophagy by increasing the expression of autophagy-related genes (LC3, ATG7, LAMP2) and accumulation of LC3-specific puncta (an autophagy maker). TUNEL staining assay showed that α-solanine significantly increased apoptosis in porcine oocytes confirmed by up-regulated the levels of BAX and CAPS3 genes. Further study revealed that exposure α-solanine (10 μM) to porcine oocytes induced ROS generation, reduced mitochondrial membrane potential. In addition, our results suggested that α-solanine (10 μM) significantly increased the levels of H3K36me3 and H3K27me3 in porcine oocytes. Taken together, these data indicated that α-solanine toxic impaired oocyte maturation and quality by inhibited cumulus cells expansion, increased abnormal spindle and CGs distribution rates, triggered autophagy/apoptosis occur, accumulated ROS, decreased mitochondrial membrane potential, and changed epigenetic modifications.

Rutin (3,3′,4′,5,7-pentahydroxyflavone-3-rhamnoglucoside) is a bioactive flavonoid from the plant kingdom. Rutin has been studied as potential anticancer agent due to its wide range of pharmacological properties including antioxidative, anti-inflammatory and anticancer. Autophagy is a conserved intracellular catabolic pathway to maintain cell homeostasis by formation of autophagosome. Processing of autophagy involves various molecules including ULK1 protein kinase complex, Beclin-1–Vps34 lipid kinase complex, ATG5, ATG12, and LC3 (light chain 3). Cargo-carried autophagosomes fuse with lysosomes resulting in autophagolysosome to eliminate vesicles and degrade cargo. However, the actions of rutin on autophagy are not clearly understood. In this study, we analyzed the effect of rutin on autophagy and inflammation in cancer cell lines. Interestingly, rutin induced autophagy in leukemia (THP-1), oral (CA9-22), and lung (A549) cell lines. TNF-α, key modulator of inflammation, was upregulated by inhibition of rutin-induced autophagy. Taken together, these data indicated that rutin induced autophagy and consequently suppressed TNF-α production.

Quercetin is a natural flavonoid phytochemical that is extracted from various plants. Having an advantages due to its varied biological properties, such as anti-inflammatory, anti-viral, anti-oxidant, and anti-cancer effects, quercetin is used to treat many diseases. Recently, it has been reported that autophagy inhibition may play a key role in anti-cancer therapy. Therefore, in this study, we investigated the molecular mechanisms and anti-cancer effects of quercetin in human osteosarcoma cells via autophagy inhibition. We ascertained that quercetin inhibited cell proliferation and induced cell death, these process is demonstrated that apoptosis via the mitochondrial pathway and the caspase cascade. Quercetin also induced autophagy which was inhibited by 3-MA, autophagy inhibitor and the blockade of autophagy promoted the quercetin-induced apoptosis, confirming that autophagy is a pro-survival process. Thus, these findings demonstrate that quercetin is an effective anti-cancer agent, and the combination of quercetin and an autophagy inhibitor should enhance the effect of anti-cancer therapy.

Fluoride has been accepted as an important material for oral health and is widely used to prevent dental caries in dentistry. However, its safety is still questioned by some. Autophagy has been implicated in cancer cell survival and death, and may play an important role in oral cancer. This study was undertaken to examine whether sodium fluoride (NaF) modulates autophagy in SCC25 human tongue squamous cell carcinoma cells. NaF demonstrated anticancer activity via autophagic and apoptotic cell death. Autophagic vacuoles were detectable using observed to form by monodansylcadaverine (MDC) and acridine orange (AO). Analysis of NaF-treated SCC25 cells for the presence of biochemical markers revealed direct effects on the conversion of LC-3II, degradation of p62/SQSTM1, cleavage formation of ATG5 and Beclin-1, and caspase activation. NaF-induced cell death was suppressed by the autophagy inhibitor 3-methyladenine (3-MA). NaF-induced autophagy was confirmed as a pro-death signal in SCC25 cells. These results implicate NaF as a novel anticancer compound for oral cancer therapy.

Cinnamaldehyde is known to have the antitumor effects in vitro and in vivo. In this study, we showed a potent and irreversible cytotoxic activity of the Cinnamaldehyde derivative 2'-benzoyloxycinnamaldehyde (BCA) in human Squamous oral cell carcinoma cell, YD-10B. BCA induced YD-10B cell apoptosis in a dose-responsive manner. BCA-induced apoptosis was associated with corresponding increases in a series of key components in the mitochondria-mediated apoptosis pathways, followed by caspase cleavage and PARP activation. We also observed that BCA induced autophagy through Akt/mTOR pathway in YD-10B cells. BCA treatment increased LC3B-II expression, and induced the formation of autophagosomes and autophagic vacuoles. These experimental findings suggest that BCA is a potent inhibitor of cell proliferation in YD-10B cells and provide new insights about leading to the possible development of a new therapeutic agent.

Chios Gum Mastic (CGM) is a natural resin extracted from the leaves of Pistacia lentiscus, a plant endemic to the Greek island of Chios. It has been used by traditional healers, and it has antibacterial, antifungal properties, and therapeutic benefits for the skin. The CGM reduces the formation of dental plaque and bacterial growth in oral saliva, and recent studies have demonstrated the role of antioxidant activity of CGM. Although CGM has been widely investigated, its protective effect against oxidative-damage to keratinocytes, as well as the relationship between CGM and autophagy, has not been investigated. The aim of this study was to assess the protective effect of CGM against H2O2-induced oxidative stress and to evaluate the autophagic features induced by CGM in human keratinocytes. The pretreatment with CGM significantly reduced apoptosis in H2O2-exposed HaCaT cells. It promoted the degradation of caspase-3, caspase-8, and caspase-9; and it induced the formation of the processed PARP. The treatment with CGM caused an increase in vesicle formation compared to control group. The level of p62 was reduced and the conversion of LC3-I to LC3-II was increased in CGM treated HaCaT cells. Also, the treatment with CGM increased cleavage of ATG5-ATG12 complex. In summary, CGM helps the cells to survive under stressful conditions by preventing apoptosis and enhancing autophagy. Besides, the present investigation provides evidence to support the antioxidant potential of CGM in vitro and opens up a new horizon for future experiments.