Meta­analysis of the autophagy­associated protein LC3 as a prognostic marker in colorectal cancer.

Microtubule-associated protein 1 light chain 3 (LC3) is an autophagy-associated gene, which is involved in the progression of a number of human malignancies. Such as Breast Cancer, Liver Cancer, and Lung Cancer. However, the role of LC3 in colorectal cancer (CC) remains to be fully elucidated. Therefore, the prognostic role of LC3 expression in CC was evaluated in the present study, with an emphasis on the clinicopathology and prognosis. Expression of LC3 in CC was examined using PubMed, Cochrane Library, Excerpta Medica Database, China Knowledge Infrastructure and Wanfang Data. Newcastle-Ottawa scale was used to screen the literature quality, and RevMan 5.4 and STATA 14.0 were used for the meta-analysis. A total of 1,689 patients from 10 studies were included in the present meta-analysis. The findings of the present study suggested that increased LC3 expression levels were associated with histological grade [odds ratio (OR)=0.91, 95% confidence interval (CI) (0.47, 1.77), P<0.001] and TNM stage [OR=0.91, 95% CI (0.47, 1.77), P<0.001], but were not associated with sex [OR=1.14, 95% CI (0.90, 1.51)], age [OR=0.89, 95% CI (0.67, 1.20)], tumor size [OR=0.78, 95% CI (0.30, 2.34)], histological grade [OR=0.82, 95% CI (0.43, 1.95)] and lymph node metastasis [OR=2.05, 95% CI (1.19, 3.60)] in CC. In addition, the increased expression of LC3 was revealed to be a prognostic factor for the overall survival of patients with CC. In conclusion, the autophagy-associated protein LC3 may be a prognostic indicator of human CC.

NEDD4 activates mitophagy by interacting with LC3 to restrain reactive oxygen species and apoptosis in Apostichopus japonicus challenged with Vibrio splendidus.

Mitophagy, the selective degradation of damaged mitochondria by autophagy, plays a crucial role in the survival of coelomocytes in Apostichopus japonicus following Vibrio splendidus infection by suppressing the generation of reactive oxygen species (ROS) and attenuating cell apoptosis. A recent study revealed that reducing the expression of the neural precursor cell-expressed developmentally downregulated gene 4 (NEDD4), an enzyme 3 (E3) ubiquitin ligase, significantly affects mitochondrial degradation. Prior to the present study, the functional role of NEDD4 in marine invertebrates was largely unexplored. Therefore, we investigated the role of NEDD4 in the activation of mitophagy, modulation of ROS levels, and induction of apoptosis in A. japonicus infected with V. splendidus. The results demonstrated that V. splendidus infection and lipopolysaccharide (LPS) challenge significantly increased the mRNA levels of NEDD4 in A. japonicus coelomocytes, which was consistent with changes in mitophagy under the same conditions. Knockdown of AjNEDD4 using specific small interfering RNAs (siRNAs) impaired mitophagy and caused accumulation of damaged mitochondria, as observed using transmission electron microscopy (TEM) and confocal microscopy. Furthermore, AjNEDD4 was localized to the mitochondria in both coelomocytes and HEK293T cells. Simultaneously, coelomocytes were treated with the inhibitor indole-3-carbinol (I3C) to confirm the regulatory role of AjNEDD4 in mitophagy. The accumulation of AjNEDD4 in the mitochondria and the level of mitophagy decreased. Subsequent investigations demonstrated that AjNEDD4 interacts directly with the microtubule-associated protein light chain 3 (LC3), a key regulator of autophagy and mitophagy, indicating its involvement in the mitophagy pathway. Moreover, AjNEDD4 interference hindered the interaction between AjNEDD4 and LC3, thereby impairing the engulfment and subsequent clearance of damaged mitochondria. Finally, AjNEDD4 interference led to a significant increase in intracellular ROS levels, followed by increased apoptosis. Collectively, these findings suggest that NEDD4 acts as a crucial regulator of mitophagy in A. japonicus and plays a vital role in maintaining cellular homeostasis following V. splendidus infection. NEDD4 suppresses ROS production and subsequent apoptosis by promoting mitophagy, thereby safeguarding the survival of A. japonicus under pathogenic conditions. Further investigation of the mechanisms underlying NEDD4-mediated mitophagy may provide valuable insights into the development of novel strategies for disease control in aquaculture farms.

Choline dehydrogenase interacts with SQSTM1 to activate mitophagy and promote coelomocyte survival in Apostichopus japonicus following Vibrio splendidus infection.

Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes, leading to the production of excessive reactive oxygen species (ROS) and irreversible apoptotic cell death. Emerging evidence suggests that mitochondrial autophagy (mitophagy) is the most effective method for eliminating damaged mitochondria and ROS, with choline dehydrogenase (CHDH) identified as a novel mitophagy receptor that can recognize non-ubiquitin damage signals and microtubule-associated protein 1 light chain 3 (LC3) in vertebrates. However, the functional role of CHDH in invertebrates is largely unknown. In this study, we observed a significant increase in the mRNA and protein expression levels of A. japonicus CHDH (AjCHDH) in response to V. splendidus infection and lipopolysaccharide (LPS) challenge, consistent with changes in mitophagy under the same conditions. Notably, AjCHDH was localized to the mitochondria rather than the cytosol following V. splendidus infection. Moreover, AjCHDH knockdown using siRNA transfection significantly reduced mitophagy levels, as observed through transmission electron microscopy and confocal microscopy. Further investigation into the molecular mechanisms underlying CHDH-regulated mitophagy showed that AjCHDH lacked an LC3-interacting region (LIR) for direct binding to LC3 but possessed a FB1 structural domain that binds to SQSTM1. The interaction between AjCHDH and SQSTM1 was further confirmed by immunoprecipitation analysis. Furthermore, laser confocal microscopy indicated that SQSTM1 and LC3 were recruited by AjCHDH in coelomocytes and HEK293T cells. In contrast, AjCHDH interference hindered SQSTM1 and LC3 recruitment to the mitochondria, a critical step in damaged mitochondrial degradation. Thus, AjCHDH interference led to a significant increase in both mitochondrial and intracellular ROS, followed by increased apoptosis and decreased coelomocyte survival. Collectively, these findings indicate that AjCHDH-mediated mitophagy plays a crucial role in coelomocyte survival in A. japonicus following V. splendidus infection.

Assays of Monitoring and Measuring Autophagic Flux for iPSC-Derived Human Neurons and Other Brain Cell Types.

Autophagy is a highly conserved, cytoprotective, catabolic process induced in response to conditions of cellular stress and nutrient deprivation. It is responsible for the degradation of large intracellular substrates such as misfolded or aggregated proteins and organelles. This self-degradative mechanism is crucial for proteostasis in post-mitotic neurons, requiring its careful regulation. Due to its homeostatic role and the implications, it has for certain disease pathologies, autophagy has become a growing area of research. We describe here two assays that can be used as part of a tool kit for measuring autophagy-lysosomal flux in human iPSC-derived neurons.One way to measure autophagic flux is through a western blotting assay, which can be used to analyze two important autophagy proteins: microtubule-associated protein 1 light chain 3 (LC3) and p62. In this chapter, we describe a western blotting assay for use in human iPSC neurons that can be used to quantify these two proteins of interest to measure autophagic flux.In addition to conventional western blotting techniques, more sophisticated tools have come available to readout autophagic flux in a sensitive and high-throughput manner. In the latter portion of this chapter, we describe a flow cytometry assay which utilizes a pH-sensitive fluorescent reporter which can also be used to measure autophagic flux.

[Acupuncture regulates autophagic flux to antagonize cerebral ischemic injury in rats].

OBJECTIVE: To observe the effect of acupuncture on the cerebral infarct volume and expressions of Beclin1, microtubule-associated protein 1 light chain 3 (LC3) and p62 proteins related to cell autophagy in rats with cerebral ischemia (CI), so as to explore its mechanisms underlying improvement of CI injury. METHODS: Male SD rats were randomized into 3 groups: sham operation, model and acupuncture which were further divided into 4 subgroups according to different ischemia time-points: 3, 6, 12 and 24 h (n=7 in each subgroup). The CI model was established by occlusion of the middle cerebral artery (MCAO) with surgical suture-embolus. For rats of the acupuncture group, acupuncture was applied to "Shuigou" (GV26) and bilateral "Neiguan" (PC6), and twirled for 1-3 min every time, 10 times altogether, and kept for 30 min. The neurological deficit score accoding to Longa's method was used for assessing the neurological function. The CI volume was measured after 2, 3, 5-triphenyltetrazolium chloride staining. The expression levels of autophagy-related proteins Beclin1，LC3 and p62 in the brain tissue were detected using Western blot. RESULTS: Compared with those of the sham operation group，the neurological deficit scores at 2, 3, 6， 12 and 24 h after CI, and the infarct volumes, the expression levels of Beclin1 and the ratios of LC3-Ⅱ/LC3-Ⅰ at 3, 6, 12 and 24 h were considerably increased (P<0.01, P<0.05), and the expression levels of p62 at 3, 6, 12 and 24 h were significantly decreased (P<0.01) in the model group. Relevant to the model group, acupuncture stimulation of GV26 and PC6 induced an obvious decrease in the neurological deficit scores at 6, 12 and 24 h, CI volumes at 3, 6, 12 and 24 h, and the expression levels of Beclin1 and the ratios of LC3-Ⅱ/LC3-Ⅰ both at 6 and 12 h (P<0.01, P<0.05), and an evident increase in the expression levels of p62 at 6, 12 and 24 h after CI (P<0.05, P<0.01). CONCLUSION: Acupuncture stimulation of GV26 and PC6 can reduce the CI volume and improve neurological function in CI rats， which may be related to its efficacy in down-regulating the expression of Beclin1 and the ratio of LC3-Ⅱ/LC3-Ⅰ, and up-regulating the expression of p62 in the ischemic brain tissue， thereby improving autophagy flux.

Association of CFH and MAP1LC3B gene polymorphisms with age-related macular degeneration in a high-altitude population.

AIM: To evaluate the association of complement factor H (CFH) and microtubule-associated protein 1 light chain 3 beta (MAP1LC3B) gene polymorphisms with the risk of age-related macular degeneration (AMD) in a high-altitude population. METHODS: The study group consisted of 172 participants with symptoms of AMD who were examined and diagnosed between January 2019 and June 2020. The control group was composed of 120 healthy individuals. Each participant was required to provide two milliliters of peripheral blood for DNA extraction. Two single nucleotide polymorphisms (SNPs) of CFH (rs1061170 and rs800292) and two SNPs of MAP1LC3B (rs8044820 and rs9903) were genotyped. The genotypes and allele frequencies of the SNPs in the study and control groups were further compared using Chi-square and Fisher's exact tests. RESULTS: In a high-altitude population, the nominally significant differences of rs800292 and rs9903's genotype AG frequencies were observed in the AMD group (P=0.034 and 0.004, respectively). The frequencies of allele G of rs800292 and allele A of rs9903 were also significantly different in the AMD group compared to the control [(P=0.034, OR=0.70, 95%CI: 0.50-0.98) and (P=0.004, OR=1.60, 95%CI: 1.15-2.22), respectively]. No significant differences in the genotype distributions (P=0.16 and 0.40, respectively) and allele frequencies (P>0.05) of rs1061170 and rs8044820 were observed in the AMD group. CONCLUSION: Genotype AG of rs800292 may be a protective factor for AMD. Conversely, rs9903 seems to be a risk factor for AMD. Therefore, allele G of rs800292 may be a protective factor, and allele A of rs9903, a risk factor for AMD in Qinghai high-altitude population.

XBP1-mediated activation of the STING signalling pathway in macrophages contributes to liver fibrosis progression.

Background & Aims: XBP1 modulates the macrophage proinflammatory response, but its function in macrophage stimulator of interferon genes (STING) activation and liver fibrosis is unknown. X-box binding protein 1 (XBP1) has been shown to promote macrophage nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3) activation in steatohepatitis. Herein, we aimed to explore the underlying mechanism of XBP1 in the regulation of STING signalling and the subsequent NLRP3 activation during liver fibrosis. Methods: XBP1 expression was measured in the human fibrotic liver tissue samples. Liver fibrosis was induced in myeloid-specific Xbp1-, STING-, and Nlrp3-deficient mice by carbon tetrachloride injection, bile duct ligation, or a methionine/choline-deficient diet. Results: Although increased XBP1 expression was observed in the fibrotic liver macrophages of mice and clinical patients, myeloid-specific Xbp1 deficiency or pharmacological inhibition of XBP1 protected the liver against fibrosis. Furthermore, it inhibited macrophage NLPR3 activation in a STING/IRF3-dependent manner. Oxidative mitochondrial injury facilitated cytosolic leakage of macrophage self-mtDNA and cGAS/STING/NLRP3 signalling activation to promote liver fibrosis. Mechanistically, RNA sequencing analysis indicated a decreased mtDNA expression and an increased BCL2/adenovirus E1B interacting protein 3 (BNIP3)-mediated mitophagy activation in Xbp1-deficient macrophages. Chromatin immunoprecipitation (ChIP) assays further suggested that spliced XBP1 bound directly to the Bnip3 promoter and inhibited the transcription of Bnip3 in macrophages. Xbp1 deficiency decreased the mtDNA cytosolic release and STING/NLRP3 activation by promoting BNIP3-mediated mitophagy activation in macrophages, which was abrogated by Bnip3 knockdown. Moreover, macrophage XBP1/STING signalling contributed to the activation of hepatic stellate cells. Conclusions: Our findings demonstrate that XBP1 controls macrophage cGAS/STING/NLRP3 activation by regulating macrophage self-mtDNA cytosolic leakage via BNIP3-mediated mitophagy modulation, thus providing a novel target against liver fibrosis. Lay summary: Liver fibrosis is a typical progressive process of chronic liver disease, driven by inflammatory and immune responses, and is characterised by an excess of extracellular matrix in the liver. Currently, there is no effective therapeutic strategy for the treatment of liver fibrosis, resulting in high mortality worldwide. In this study, we found that myeloid-specific Xbp1 deficiency protected the liver against fibrosis in mice, while XBP1 inhibition ameliorated liver fibrosis in mice. This study concluded that targeting XBP1 signalling in macrophages may provide a novel strategy for protecting the liver against fibrosis.

MicroRNA-34c-5p provokes isoprenaline-induced cardiac hypertrophy by modulating autophagy via targeting ATG4B.

Pathological cardiac hypertrophy serves as a significant foundation for cardiac dysfunction and heart failure. Recently, growing evidence has revealed that microRNAs (miRNAs) play multiple roles in biological processes and participate in cardiovascular diseases. In the present research, we investigate the impact of miRNA-34c-5p on cardiac hypertrophy and the mechanism involved. The expression of miR-34c-5p was proved to be elevated in heart tissues from isoprenaline (ISO)-infused mice. ISO also promoted miR-34c-5p level in primary cultures of neonatal rat cardiomyocytes (NRCMs). Transfection with miR-34c-5p mimic enhanced cell surface area and expression levels of foetal-type genes atrial natriuretic factor (Anf) and ß-myosin heavy chain (ß-Mhc) in NRCMs. In contrast, treatment with miR-34c-5p inhibitor attenuated ISO-induced hypertrophic responses. Enforced expression of miR-34c-5p by tail intravenous injection of its agomir led to cardiac dysfunction and hypertrophy in mice, whereas inhibiting miR-34c-5p by specific antagomir could protect the animals against ISO-triggered hypertrophic abnormalities. Mechanistically, miR-34c-5p suppressed autophagic flux in cardiomyocytes, which contributed to the development of hypertrophy. Furthermore, the autophagy-related gene 4B (ATG4B) was identified as a direct target of miR-34c-5p, and miR-34c-5p was certified to interact with 3' untranslated region of Atg4b mRNA by dual-luciferase reporter assay. miR-34c-5p reduced the expression of ATG4B, thereby resulting in decreased autophagy activity and induction of hypertrophy. Inhibition of miR-34c-5p abolished the detrimental effects of ISO by restoring ATG4B and increasing autophagy. In conclusion, our findings illuminate that miR-34c-5p participates in ISO-induced cardiac hypertrophy, at least partly through suppressing ATG4B and autophagy. It suggests that regulation of miR-34c-5p may offer a new way for handling hypertrophy-related cardiac dysfunction.

ROS-mediated BNIP3-dependent mitophagy promotes coelomocyte survival in Apostichopus japonicus in response to Vibrio splendidus infection.

Organisms produce high levels of reactive oxygen species (ROS) to kill pathogens or act as signaling molecules to induce immune responses; however, excessive ROS can result in cell death. To maintain ROS balance and cell survival, mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates. In marine invertebrates, however, mitophagy and its functions remain largely unknown. In the current study, Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential (ΔΨm) and mitophagosome formation. The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide (LPS) treatment increased mitophagy flux. To explore the regulatory mechanism of mitophagy, we cloned Bcl2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), a common mitophagy receptor, from sea cucumber Apostichopus japonicus (AjBNIP3) and confirmed that AjBNIP3 was significantly induced and accumulated in mitochondria after V. splendidus infection and LPS exposure. At the mitochondrial membrane, AjBNIP3 interacts with microtubule-associated protein 1 light chain 3 (LC3) on phagophore membranes to mediate mitophagy. After AjBNIP3 interference, mitophagy flux decreased significantly. Furthermore, AjBNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide (H2O2), ROS scavengers, and ROS inhibitors. Finally, inhibition of BNIP3-mediated mitophagy by AjBNIP3 small interfering RNA (siRNA) or high concentrations of lactate increased apoptosis and decreased coelomocyte survival. These findings highlight the essential role of AjBNIP3 in damaged mitochondrial degradation during mitophagy. This mitophagy activity is required for coelomocyte survival in A. japonicus against V. splendidus infection.

Intracellular Toxic Advanced Glycation End-Products in 1.4E7 Cell Line Induce Death with Reduction of Microtubule-Associated Protein 1 Light Chain 3 and p62.

BACKGROUND: The death of pancreatic islet ß-cells (ß-cells), which are the insulin-producing cells, promote the pathology in both Type 1 and Type 2 diabetes mellitus (DM) (T1DM and T2DM), and they are protected by autophagy which is one of the mechanisms of cell survival. Recently, that some advanced glycation end-products (AGEs), such as methylglyoxial-derived AGEs and Nε-carboxymethyllysine, induced the death of ß-cells were revealed. In contrast, we had reported AGEs derived from glyceraldehyde (GA, the metabolism intermediate of glucose and fructose) are considered to be toxic AGEs (TAGE) due to their cytotoxicity and role in the pathogenesis of T2DM. More, serum levels of TAGE are elevated in patients with T1 and T2DM, where they exert cytotoxicity. AIM: We researched the cytotoxicity of intracellular and extracellular TAGE in ß-cells and the possibility that intracellular TAGE were associated with autophagy. METHODS: 1.4E7 cells (a human ß-cell line) were treated with GA, and analyzed viability, quantity of TAGE, microtubule-associated protein 1 light chain 3 (LC3)-I, LC3-II, and p62. We also examined the viability of 1.4E7 cells treated with TAGE-modified bovine serum albumin, a model of TAGE in the blood. RESULTS: Intracellular TAGE induced death of 1.4E7 cells, decrease of LC3-I, LC3-II, and p62. Extracellular TAGE didn't show cytotoxicity in the physiological concentration. CONCLUSION: Intracellular TAGE induced death of ß-cells more strongly than extracellular TAGE, and may suppress autophagy via reduction of LC3-I, LC3-II, and p62 to inhibit the degradation of them.

Andrographolide derivative as antagonist of vitamin D receptor to induce lipidation of microtubule associate protein 1 light chain 3 (LC3).

Lipidation of microtubule associated protein 1 light chain 3 (LC3) is the critical step in autophagosome formation, numerous efforts have been made to design and develop small molecules that trigger LC3 lipidation to activate autophagy. In this study, we discovered a series of andrographolide derivatives as potent antagonists of vitamin D receptor (VDR) by luciferase reporter assay. Structure-activity-relationship study revealed that andrographolide derivative ZAV-12 specifically inhibited VDR signaling but not NF-κB or STAT3 activation. Western blot analysis indicates that ZAV-12 markedly triggered lipidation of LC3 in MPP+-induced Parkinsonism in vitro in an mTOR-independent manner. The ZAV-12 triggered lipidation was mediated through SREBP2 activation instead of changing expression levels of lipid synthesis genes. Furthermore, ZAV-12 treatment increased the ratio of LC3-II/LC3-I and oligomerization of A53T α-synuclein (SNCA) in SNCA triggered neurotoxicity. Taken together, these results demonstrate the therapeutic potential of VDR antagonist as novel drug candidate for neurodegenerative diseases.

Cholesterol-associated lysosomal disorder triggers cell death of hematological malignancy: Dynamic analysis on cytotoxic effects of LW-218.

The integrity of lysosomes is of vital importance to survival of tumor cells. We demonstrated that LW-218, a synthetic flavonoid, induced rapid lysosomal enlargement accompanied with lysosomal membrane permeabilization in hematological malignancy. LW-218-induced lysosomal damage and lysosome-dependent cell death were mediated by cathepsin D, as the lysosomal damage and cell apoptosis could be suppressed by depletion of cathepsin D or lysosome alkalization agents, which can alter the activity of cathepsins. Lysophagy, was initiated for cell self-rescue after LW-218 treatment and correlated with calcium release and nuclei translocation of transcription factor EB. LW-218 treatment enhanced the expression of autophagy-related genes which could be inhibited by intracellular calcium chelator. Sustained exposure to LW-218 exhausted the lysosomal capacity so as to repress the normal autophagy. LW-218-induced enlargement and damage of lysosomes were triggered by abnormal cholesterol deposition on lysosome membrane which caused by interaction between LW-218 and NPC intracellular cholesterol transporter 1. Moreover, LW-218 inhibited the leukemia cell growth in vivo. Thus, the necessary impact of integral lysosomal function in cell rescue and death were illustrated.

Targeting autophagy-related protein kinases for potential therapeutic purpose.

Autophagy, defined as a scavenging process of protein aggregates and damaged organelles mediated by lysosomes, plays a significant role in the quality control of macromolecules and organelles. Since protein kinases are integral to the autophagy process, it is critically important to understand the role of kinases in autophagic regulation. At present, intervention of autophagic processes by small-molecule modulators targeting specific kinases has becoming a reasonable and prevalent strategy for treating several varieties of human disease, especially cancer. In this review, we describe the role of some autophagy-related kinase targets and kinase-mediated phosphorylation mechanisms in autophagy regulation. We also summarize the small-molecule kinase inhibitors/activators of these targets, highlighting the opportunities of these new therapeutic agents.

NPD1 inhibits excessive autophagy by targeting RNF146 and wnt/ß-catenin pathway in cerebral ischemia-reperfusion injury.

Objective: Cerebral ischemia-reperfusion (I/R) injury is a common pathological feature in ischemic stroke. Autophagy plays a key role in I/R-induced neuronal death. Neuroprotectin D1 (NPD1) is a docosahexaenoic acid derivative with neuroprotective and anti-inflammatory properties. The purpose of this study was to investigate the mediatory role of NPD1 on I/R-induced injury and to elucidate the underlying mechanisms involved in this process.Methods: An I/R injury model was established in PC12 cells induced by oxygen and glucose deprivation/reoxygenation (OGD/R). NPD1 at increasing doses (5, 10, 20, 50, 100 nM) were added to cells one hour before OGD/R. To investigate the effect of ring finger protein 146 (RFP146) deficiency in I/R injury, PC12 cells were transiently transfected with small interfering RNF146 before further experiment.Results: Compared to the controls, OGD/R-challenged cells exhibited significantly decreased cell viability, induced oxidative stress, and excessive autophagic cell death following OGD/R. Pretreatment with NPD1 protected cells against ischemic injury as evidenced by enhanced cell survival, decreased oxidative stress markers, and a lower level of autophagy compared to drug-free group. OGD/R also increased the level of RFP146 and inhibited the expression of ß-catenin in PC12 cells. NPD1 treatment promoted the production of RNF146 and ß-catenin in cells following OGD/R experiment. Moreover, RNF146 deficiency significantly inhibited ß-catenin expression and reversed the protective effects of NPD1 in OGD/R-induced cells.Conclusion: NPD1 alleviated excessive autophagy via regulating RNF146 and Wnt/ß-catenin signaling, suggesting the potential therapeutic use of NPD1 for the protection against cerebral I/R injury.

Cell-Penetrating Nanoparticles Activate the Inflammasome to Enhance Antibody Production by Targeting Microtubule-Associated Protein 1-Light Chain 3 for Degradation.

Engineered nanoparticles could trigger inflammatory responses and potentiate a desired innate immune response for efficient immunotherapy. Here we report size-dependent activation of innate immune signaling pathways by gold (Au) nanoparticles. The ultrasmall-size (<10 nm) Au nanoparticles preferentially activate the NLRP3 inflammasome for Caspase-1 maturation and interleukin-1ß production, while the larger-size Au nanoparticles (>10 nm) trigger the NF-κB signaling pathway. Ultrasmall (4.5 nm) Au nanoparticles (Au4.5) activate the NLRP3 inflammasome through directly penetrating into cell cytoplasm to promote robust ROS production and target autophagy protein-LC3 (microtubule-associated protein 1-light chain 3) for proteasomal degradation in an endocytic/phagocytic-independent manner. LC3-dependent autophagy is required for inhibiting NLRP3 inflammasome activation and plays a critical role in the negative control of inflammasome activation. Au4.5 nanoparticles promote the degradation of LC3, thus relieving the LC3-mediated inhibition of the NLRP3 inflammasome. Finally, we show that Au4.5 nanoparticles could function as vaccine adjuvants to markedly enhance ovalbumin (OVA)-specific antibody production in an NLRP3-dependent pattern. Our findings have provided molecular insights into size-dependent innate immune signaling activation by cell-penetrating nanoparticles and identified LC3 as a potential regulatory target for efficient immunotherapy.

[Electroacupuncture pretreatment alleviated cerebral ischemia-reperfusion injury via suppressing autophagy in cerebral cortex tissue in rats].

OBJECTIVE: To investigate the effect of electroacupuncture (EA) preconditioning on autophagy in cerebral cortex tissues of rats with cerebral ischemia-reperfusion injury (CIRI), so as to explore its mechanisms underlying improvement of CIRI. METHODS: Thirty-three male Sprague-Dawley rats were randomly divided into sham operation, model and EA groups (n=11 in each group). EA (2 Hz/15 Hz, 1 mA) was applied to "Baihui"(GV20), "Quchi" (LI11) and "Zusanli" (ST36) for 30 min, once daily for 5 days, followed by establishment of CIRI model by occlusion of the middle cerebral artery (MCAO) for 1.5 h and reperfusion for 24 h. The neurological deficit score was assessed in reference to Longa's methods, and the infarct volume assessed by 2,3,5-triphenyltetrazolium chloride staining. The density of dendrite spines of neurons in the ischemic cerebral cortex tissue was detected by Golgi's staining, the autophagosome observed by electron microscopy, and the expression levels of microtubule-associated protein 1 light chain 3 (LC3) and p62 (a selective autophagy substrate) were detected by Western blot. RESULTS: Compared with the sham operation group, the neurological deficit score and infarct volume were significantly increased (P<0.01), the number of autophagosomes and the ratio of LC3-Ⅱ/LC3-Ⅰ also significantly increased (P<0.01), while the expression level of p62 was notably decreased in the model group (P<0.01). Following the intervention and in comparison with the model group, the neurological deficit score and infarct volume were significantly reduced (P<0.01), the number of autophagosomes and the ratio of LC3-Ⅱ/LC3-Ⅰ obviously decreased (P<0.01), and the expression of p62 was significantly up-regulated in the EA group (P<0.01). CONCLUSION: EA pretreatment is effective in improving CIRI in rats, which may be realized through suppressing autophagy in the ischemic cerebral cortex tissue.

[Penetrative needling improves neurological function by up-regulating expression of autophagy related protein LC3 in rats with hemorrhagic stroke].

OBJECTIVE: To observe the effect of penetrative needling from "Baihui" (GV20) to "Qubin" (GB7) on neurological function and expression of autophagy related protein microtubule-associated protein, light chain 3 (LC3) in rats with hemorrhagic stroke, so as to explore its mechanism underlying improvement of hemorrhagic stroke. METHODS: A total of 120 male SD rats were randomly divided into sham operation, model, non-acupoint, acupuncture and medication (Rapamycin) groups which were further divided into two time-point subgroups (3, 7 days after modeling, n=12/subgroup). The intracerebral hemorrhage model was established by injection of the rat's auto-blood (50 µL) into the putaman region. Penetrative needling from GV20 to GB7 or sham acupoints (about 1 cm beside GV20 and GB7) was conducted for 30 min, twice daily for 7 days. For rats of the medication group, Rapamycin solution (7 µmol/L) was injected into the right lateral ventricle. The neurological functions (locomotor and balance deficits) were evaluated according to suspended wire test (0-6 points) and horizontal board walking test (0-6 points). Immunohistochemistry and Western blot were used to detect the expression of total LC3 and expression of LC3-Ⅰ and LC3-Ⅱ proteins in the ischemic penumbra region of brain tissue, respectively. RESULTS: After modeling, the neurological function scores were significantly decreased on day 3 and 7, the levels of LC3-Ⅱ/Ⅰ and LC3 protein on day 3 and 7 were significantly increased in the model group relevant to the sham operation group (P<0.05). Following the interventions, the neurological function scores as well as LC3-Ⅱ/Ⅰ and LC3 protein expression were significantly increased in both acupuncture and medication groups compared with the model group (P<0.05). The effect of Rapamycin was obviously stronger than that of penetrative needling in up-regulating the expression of LC3-Ⅱ/Ⅰ and LC3 protein (P<0.05). CONCLUSION: Penetrative needling can improve neurologic function in hemorrhagic stroke rats, which is related with its effect in up-regulating the expression of autophagy-related protein LC3.

LW6 enhances chemosensitivity to gemcitabine and inhibits autophagic flux in pancreatic cancer.

The efficacy of gemcitabine therapy is often insufficient for the treatment of pancreatic cancer. The current study demonstrated that LW6, a chemical inhibitor of hypoxia-inducible factor 1α, is a promising drug for enhancing the chemosensitivity to gemcitabine. LW6 monotherapy and the combination therapy of LW6 plus gemcitabine significantly inhibited cell proliferation and enhanced cell death in pancreatic cancer cells. This combination therapy also significantly reduced the tumor weight in a syngeneic orthotopic pancreatic carcinoma model without causing toxic side effects. In addition, this study provides insight into the mechanism of how LW6 interferes with the pathophysiology of pancreatic cancer. The results revealed that LW6 inhibited autophagic flux, which is defined by the accumulation of microtubule-associated protein 1 light chain 3 (LC3) and p62/SQSTM1. Moreover, these results were verified by the analysis of a tandem RFP-GFP-tagged LC3 protein. Thence, for the first time, these data demonstrate that LW6 enhances the anti-tumor effects of gemcitabine and inhibits autophagic flux. This suggests that the combination therapy of LW6 plus gemcitabine may be a novel therapeutic strategy for pancreatic cancer patients.

Apoptosis, necroptosis and autophagy in colorectal cancer: Associations with tumor aggressiveness and p53 status.

OBJECTIVE: Cleaved caspase-3 (CC3), phosphorylated-mixed-lineage kinase domain-like protein (p-MLKL), and microtubule-associated protein-1 light chain-3B (LC3B) have pivotal functions in apoptosis, necroptosis, and autophagy, respectively. In vitro studies have shown that interaction of these proteins are complex and their roles in cancer can be influenced by many factors. However, these findings are not adequately assessed in human tissues. Here, we determined CC3, p-MLKL, and LC3B expression in colorectal cancers (CRCs), and assessed their associations with clinicopathological parameters, and with KRAS and p53 status. METHODS: We immunohistochemically assessed 113 CRC specimens for levels of CC3, p-MLKL, LC3B, and p53. KRAS gene status was analyzed using the Scorpion- amplification refractory mutation system. RESULTS: High levels of CC3 (CC3High) and LC3B (LC3BHigh) were detected in 38% and 35% of the 113 CRCs, respectively, but no or only a few p-MLKL-positive cells were observed in any of the tumors. CC3High was significantly associated with high pT status (P = 0.03), vascular invasion (P = 0.03) and high pStage (P = 0.04) and was marginally associated with lymph node (P = 0.06) and distant metastases (P = 0.06). LC3BHigh was also significantly associated with high pT status (P = 0.02) and lymphatic invasion (P = 0.002), and was marginally associated with nerve plexus invasion (P = 0.06). In combined analysis, compared with CC3Low/LC3BLow tumors, tumors that were either CC3High, LC3BHigh, or both were significantly associated with high pT status (P = 0.0007), lymphatic invasion (P = 0.03), vascular invasion (P = 0.003), distant metastasis (P = 0.04) and high pStage (P = 0.04). LC3BHigh was significantly associated with a mutant-type expression pattern of p53 (P = 0.003). CONCLUSION: To the best of our knowledge, this is the first study to examine the combination of CC3/LC3B and p-MLKL expression in clinical CRC samples and to correlate these expression data with clinicopathological parameters and EGFR and p53 status. Our results suggest that necroptosis is a rare process in CRC, apoptosis and autophagy are upregulated in aggressive CRCs, and p53 mutation may lead to the upregulation of autophagy.

miR-204-5p promotes diabetic retinopathy development via downregulation of microtubule-associated protein 1 light chain 3.

Diabetic retinopathy (DR) is a chronic and progressive complication of diabetes mellitus. DR impairs sight due to neuronal and vascular dysfunction in the retina. It is critical to investigate the pathogenesis of DR to develop effective treatment. In the present study, a streptozotocin (STZ)-induced diabetic rat model was constructed and the expression of microRNA (miR)-204-5p and vascular endothelial growth factor (VEGF) were determined. Immunohistochemistry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were employed to detect the effects of miR-204-5p on the expression of microtubule-associated protein 1 light chain 3 (LC3B). RT-qPCR analysis demonstrated that miR-204-5p and VEGF were significantly upregulated in the retina tissue of diabetic rats compared with the control group (P<0.01). Immunohistochemistry and western blotting revealed that the protein expression levels of LC3B-II and the ratio of LC3B-II/LC3B-I were significantly suppressed in the diabetes group compared with the control (P<0.01). In retinal tissues, anti-miR-204-5p treatment significantly enhanced the protein expression levels of LC3B-II and the ratio of LC3B-II/LC3B-I and these levels were significantly reduced in response to miR-204-5p mimic treatment compared with the negative miR control (P<0.01). In rat retinal endothelial cells isolated from diabetic rats, anti-miR-204-5p treatment increased the number of autophagic vacuoles, and significantly promoted LC3B-II expression and the LC3B-II/LC3B-I ratio compared with the negative control (P<0.01). The results of the present study revealed that miR-204-5p downregulated the expression of LC3B-II to inhibit autophagy in DR. Therefore, miR-204-5p may be considered as a novel effective therapeutic target during the development of DR.