-
Zhongguo Zhen Jiu = Chinese Acupuncture... Jun 2024To observe the effects of electroacupuncture (EA) on the autophagy of ovarian granulosa cells in rats with premature ovarian insufficiency (POI), and explore the...
OBJECTIVE
To observe the effects of electroacupuncture (EA) on the autophagy of ovarian granulosa cells in rats with premature ovarian insufficiency (POI), and explore the mechanism of EA in improving POI.
METHODS
Thirty-two female SD rats were randomly divided into a blank group (=8) and a model making group (=24). The rats in the model making group were injected intraperitoneally with cyclophosphamide for 15 days to establish the POI model (the dosage on the 1st day was 50 mg/kg, and 8 mg/kg from the 2nd day to 15th day). The successfully modeled rats were then randomly divided into a model group, an EA group, and an estradiol (E2) group, with 8 rats in each group. Rats in the EA group received EA at bilateral "Gongsun" (SP 4) with continuous wave, frequency of 2 Hz, and current intensity of 0.1 to 1 mA, 20 min per treatment, once daily for 14 days. Rats in the E2 group were administered with E2 (0.01 mg/mL) by gavage (10 mL/kg), once daily for 14 days. The changes in estrous cycle were observed by rapid Giemsa staining before and after modeling. After intervention, ovarian tissue morphology was observed by HE staining; serum levels of follicle-stimulating hormone (FSH), E2, anti-Mullerian hormone (AMH), and inhibin B (INHB) were detected by ELISA; immunofluorescence staining was used to observe the expression of p62 in ovarian granulosa cells; the ultrastructure of ovarian granulosa cells was observed by transmission electron microscopy, and the number of autophagosomes and autolysosomes was compared; Western blot and real-time fluorescence quantitative PCR were used to detect the protein and mRNA expression of p62, Beclin-1, and microtubule-associated protein 1A/1B-light chain 3 (LC3) in ovarian tissue.
RESULTS
The results of vaginal smears in the blank group showed regular cyclical changes; the rats in the model group showed prolonged estrous cycle or cycle arrest, mostly in proestrus or metestrus, with overall ovarian atrophy, disordered structure, and decreased granulosa cells. Compared with the blank group, rats in the model group showed increased serum FSH level (<0.01), decreased serum levels of E2, AMH, and INHB (<0.01), decreased positive expression of p62 in ovarian granulosa cells (<0.01), with obvious swelling of ovarian granulosa cells, mild to moderate swelling of mitochondria, slight expansion of rough endoplasmic reticulum, and hypertrophy of Golgi apparatus; the number of autophagosomes and autolysosomes in the ovaries was increased (<0.01), the expression of p62 protein and mRNA was decreased (<0.01), and the expression of Beclin-1 and LC3 protein and mRNA in ovarian tissue was increased (<0.01). Compared with the model group, rats in the EA group and the E2 group showed decreased serum FSH levels (<0.01), increased levels of E2, AMH, and INHB (<0.01), increased positive expression of p62 in ovarian granulosa cells (<0.01), alleviated degree of ovarian granulosa cell damage, with relatively intact organelle morphology, and decreased number of autophagosomes and autolysosomes in the ovaries (<0.01); the rats also showed increased expression of p62 protein and mRNA (<0.01), and decreased expression of Beclin-1 and LC3 protein and mRNA (<0.01) in ovarian tissue.
CONCLUSION
EA at "Gongsun" (SP 4) could improve ovarian reserve function in POI rats by reducing the number of autophagosomes and autolysosomes, up-regulating p62 expression, and down-regulating Beclin-1 and LC3 expression, thus inhibiting autophagy of ovarian granulosa cells, and regulating the serum levels of FSH, E2, AMH, and INHB.
Topics: Animals; Female; Electroacupuncture; Primary Ovarian Insufficiency; Rats; Autophagy; Rats, Sprague-Dawley; Humans; Granulosa Cells; Disease Models, Animal
PubMed: 38867630
DOI: 10.13703/j.0255-2930.20230930-k0001 -
Frontiers in Immunology 2024Dengue virus (DENV), transmitted by infected mosquitoes, is a major public health concern, with approximately half the world's population at risk for infection. Recent...
Dengue virus (DENV), transmitted by infected mosquitoes, is a major public health concern, with approximately half the world's population at risk for infection. Recent decades have increasing incidence of dengue-associated disease alongside growing frequency of outbreaks. Although promising progress has been made in anti-DENV immunizations, post-infection treatment remains limited to non-specific supportive treatments. Development of antiviral therapeutics is thus required to limit DENV dissemination in humans and to help control the severity of outbreaks. Dendritic cells (DCs) are amongst the first cells to encounter DENV upon injection into the human skin mucosa, and thereafter promote systemic viral dissemination to additional human target cells. Autophagy is a vesicle trafficking pathway involving the formation of cytosolic autophagosomes, and recent reports have highlighted the extensive manipulation of autophagy by flaviviruses, including DENV, for viral replication. However, the temporal profiling and function of autophagy activity in DENV infection and transmission by human primary DCs remains poorly understood. Herein, we demonstrate that mechanisms of autophagosome formation and extracellular vesicle (EV) release have a pro-viral role in DC-mediated DENV transmission. We show that DENV exploits early-stage canonical autophagy to establish infection in primary human DCs. DENV replication enhanced autophagosome formation in primary human DCs, and intrinsically-heightened autophagosome biogenesis correlated with relatively higher rates of DC susceptibility to DENV. Furthermore, our data suggest that viral replication intermediates co-localize with autophagosomes, while productive DENV infection introduces a block at the late degradative stages of autophagy in infected DCs but not in uninfected bystander cells. Notably, we identify for the first time that approximately one-fourth of DC-derived CD9/CD81/CD63+ EVs co-express canonical autophagy marker LC3, and demonstrate that DC-derived EV populations are an alternative, cell-free mechanism by which DCs promote DENV transmission to additional target sites. Taken together, our study highlights intersections between autophagy and secretory pathways during viral infection, and puts forward autophagosome accumulation and viral RNA-laden EVs as host determinants of DC-mediated DENV infection in humans. Host-directed therapeutics targeting autophagy and exocytosis pathways thus have potential to enhance DC-driven resistance to DENV acquisition and thereby limit viral dissemination by initial human target cells following mosquito-to-human transmission of DENV.
Topics: Humans; Dengue Virus; Dendritic Cells; Autophagy; Dengue; Autophagosomes; Secretory Pathway; Virus Replication; Extracellular Vesicles; Cells, Cultured
PubMed: 38863700
DOI: 10.3389/fimmu.2024.1260439 -
Frontiers in Cellular Neuroscience 2024Transforming growth factor β1 (TGF-β1) has a neuroprotective function in traumatic brain injury (TBI) through its anti-inflammatory and immunomodulatory properties....
Transforming growth factor β1 (TGF-β1) has a neuroprotective function in traumatic brain injury (TBI) through its anti-inflammatory and immunomodulatory properties. However, the precise mechanisms underlying the neuroprotective actions of TGF-β1 on the cortex require further investigation. In this study, we were aimed to investigate the regulatory function of TGF-β1 on neuronal autophagy and apoptosis using an primary cortical neuron trauma-injury model. LDH activity was assayed to measure cell viability, and intracellular [Ca] was measured using Fluo-4-AM in an primary cortical neuron trauma-injury model. RNA-sequencing (RNAseq), immunofluorescent staining, transmission electron microscopy (TEM), western blot and CTSD activity detection were employed. We observed significant enrichment of DEGs related to autophagy, apoptosis, and the lysosome pathway in trauma-injured cortical neurons. TEM confirmed the presence of autophagosomes as well as autophagolysosomes. Western blot revealed upregulation of autophagy-related protein light chain 3 (LC3-II/LC3-I), sequestosome 1 (SQSTM1/p62), along with apoptosis-related protein cleaved-caspase 3 in trauma-injured primary cortical neurons. Furthermore, trauma-injured cortical neurons showed an upregulation of lysosomal marker protein (LAMP1) and lysosomal enzyme mature cathepsin D (mCTSD), but a decrease in the activity of CTSD enzyme. These results indicated that apoptosis was up-regulated in trauma- injured cortical neurons at 24 h, accompanied by lysosomal dysfunction and impaired autophagic flux. Notably, TGF-β1 significantly reversed these changes. Our results suggested that TGF-β1 exerted neuroprotective effects on trauma- injured cortical neurons by reducing lysosomal dysfunction, decreasing the accumulation of autophagosomes and autophagolysosomes, and enhancing autophagic flux.
PubMed: 38863498
DOI: 10.3389/fncel.2024.1381279 -
Nature Communications Jun 2024Cancer-associated fibroblasts (CAFs) have emerged as a dominant non-hematopoietic cell population in the tumour microenvironment, serving diverse functions in tumour...
Cancer-associated fibroblasts (CAFs) have emerged as a dominant non-hematopoietic cell population in the tumour microenvironment, serving diverse functions in tumour progression. However, the mechanisms via which CAFs influence the anti-tumour immunity remain poorly understood. Here, using multiple tumour models and biopsies from cancer patients, we report that α-SMA CAFs can form immunological synapses with Foxp3 regulatory T cells (Tregs) in tumours. Notably, α-SMA CAFs can phagocytose and process tumour antigens and exhibit a tolerogenic phenotype which instructs movement arrest, activation and proliferation in Tregs in an antigen-specific manner. Moreover, α-SMA CAFs display double-membrane structures resembling autophagosomes in their cytoplasm. Single-cell transcriptomic data showed an enrichment in autophagy and antigen processing/presentation pathways in α-SMA-expressing CAF clusters. Conditional knockout of Atg5 in α-SMA CAFs promoted inflammatory re-programming in CAFs, reduced Treg cell infiltration and attenuated tumour development. Overall, our findings reveal an immunosuppressive mechanism entailing the formation of synapses between α-SMA CAFs and Tregs in an autophagy-dependent manner.
Topics: T-Lymphocytes, Regulatory; Cancer-Associated Fibroblasts; Humans; Immunological Synapses; Animals; Tumor Microenvironment; Mice; Autophagy; Actins; Autophagy-Related Protein 5; Neoplasms; Mice, Inbred C57BL; Forkhead Transcription Factors; Female; Mice, Knockout
PubMed: 38862534
DOI: 10.1038/s41467-024-49282-1 -
Scientific Reports Jun 2024Lung cancer is the most common oncological disease worldwide, with non-small cell lung cancer accounting for approximately 85% of lung cancer cases. α-Hederin is a...
Lung cancer is the most common oncological disease worldwide, with non-small cell lung cancer accounting for approximately 85% of lung cancer cases. α-Hederin is a monodesmosidic triterpenoid saponin isolated from the leaves of Hedera helix L. or Nigella sativa and has been extensively studied for its antitumor activity against a variety of tumor cells. It has been suggested that α-Hederin is a potential regulator of autophagy and has high promise for application. However, the specific mechanism and characteristics of α-Hederin in regulating autophagy are not well understood. In this study, we confirmed the potential of α-Hederin application in lung cancer treatment and comprehensively explored the mechanism and characteristics of α-Hederin in regulating autophagy in lung cancer cells. Our results suggest that α-Hederin is an incomplete autophagy inducer that targets mTOR to activate the classical autophagic pathway, inhibits lysosomal acidification without significantly affecting the processes of autophagosome transport, lysosome biogenesis, autophagosome and lysosome fusion, and finally leads to impaired autophagic flux and triggers autophagic damage in NSCLC.
Topics: Humans; Carcinoma, Non-Small-Cell Lung; Lysosomes; Autophagy; Lung Neoplasms; Oleanolic Acid; Saponins; Cell Line, Tumor; TOR Serine-Threonine Kinases; Autophagosomes; A549 Cells
PubMed: 38858422
DOI: 10.1038/s41598-024-63348-6 -
Autophagy Jun 2024The serine/threonine kinase, PINK1, and the E3 ubiquitin ligase, PRKN/Parkin facilitate LC3-dependent autophagosomal encasement and lysosomal clearance of dysfunctional...
The serine/threonine kinase, PINK1, and the E3 ubiquitin ligase, PRKN/Parkin facilitate LC3-dependent autophagosomal encasement and lysosomal clearance of dysfunctional mitochondria, and defects in this pathway contribute to the pathogenesis of numerous cardiometabolic and neurological diseases. Although dynamic actin remodeling has recently been shown to play an important role in governing spatiotemporal control of mitophagy, the mechanisms remain unclear. We recently found that the RhoGAP, ARHGAP26/GRAF1 is a PRKN-binding protein that is rapidly recruited to damaged mitochondria where upon phosphorylation by PINK1 it serves to coordinate phagophore capture by regulating mitochondrial-associated actin remodeling and by facilitating PRKN-LC3 interactions. Because ARHGAP26 phosphorylation on PINK1-dependent sites is dysregulated in human heart failure and ARHGAP26 depletion in mouse hearts blunts mitochondrial clearance and attenuates compensatory metabolic adaptations to stress, this enzyme may be a tractable target to treat the many diseases associated with mitochondrial dysfunction.
PubMed: 38855880
DOI: 10.1080/15548627.2024.2361576 -
Experimental Cell Research Jul 2024Autophagy phenomenon in the cell maintains proteostasis balance by eliminating damaged organelles and protein aggregates. Imbalance in autophagic flux may cause...
Autophagy phenomenon in the cell maintains proteostasis balance by eliminating damaged organelles and protein aggregates. Imbalance in autophagic flux may cause accumulation of protein aggregates in various neurodegenerative disorders. Regulation of autophagy by either calcium or chaperone play a key role in the removal of protein aggregates from the cell. The neuromuscular rare genetic disorder, GNE Myopathy, is characterized by accumulation of rimmed vacuoles having protein aggregates of β-amyloid and tau that may result from altered autophagic flux. In the present study, the autophagic flux was deciphered in HEK cell-based model for GNE Myopathy harbouring GNE mutations of Indian origin. The refolding activity of HSP70 chaperone was found to be reduced in GNE mutant cells compared to wild type controls. The autophagic markers LC3II/I ratio was altered with increased number of autophagosome formation in GNE mutant cells compared to wild type cells. The cytosolic calcium levels were also increased in GNE mutant cells of Indian origin. Interestingly, treatment of GNE mutant cells with HSP70 activator, BGP-15, restored the expression and refolding activity of HSP70 along with autophagosome formation. Treatment with calcium chelator, BAPTA-AM restored the cytoplasmic calcium levels and autophagosome formation but not LC3II/I ratio significantly. Our study provides insights towards GNE mutation specific response for autophagy regulation and opens up a therapeutic advancement area in calcium signalling and HSP70 function for GNE related Myopathy.
Topics: Humans; Autophagy; Mutation; Calcium; Distal Myopathies; HSP70 Heat-Shock Proteins; Multienzyme Complexes; HEK293 Cells; Autophagosomes; India
PubMed: 38852763
DOI: 10.1016/j.yexcr.2024.114118 -
Biochemical and Biophysical Research... Sep 2024Autophagy is a critical catabolic pathway that enables cells to survive and adapt to stressful conditions, especially nutrient deprivation. The fusion of autophagic...
Autophagy is a critical catabolic pathway that enables cells to survive and adapt to stressful conditions, especially nutrient deprivation. The fusion of autophagic vacuoles with lysosomes is the final step of autophagy, which degrades the engulfed contents into metabolic precursors for re-use by the cell. O-GlcNAc transferase (OGT) plays a crucial role in regulating autophagy flux in response to nutrient stress, particularly by targeting key proteins involved in autophagosome-lysosome fusion. However, the role of OGT in basal autophagy, which occurs at a low and constitutive levels under growth conditions, remains poorly understood. Silencing or inhibition of OGT was used to compare the effect of OGT downregulation on autophagy flux in the non-cancerous CCD841CoN and cancerous HCT116 human colon cell lines under nutrient-rich conditions. We provide evidence that the reduction of OGT activity impairs the maturation of autophagosomes, thereby blocking the completion of basal autophagy in both cell lines. Additionally, OGT inhibition results in the accumulation of lysosomes and enlarged late endosomes in the perinuclear region, as demonstrated by confocal imaging. This is associated with a defect in the localization of the small GTPase Rab7 to these organelles. The regulation of transport and fusion events between the endosomal and lysosomal compartments is crucial for maintaining the autophagic flux. These findings suggest an interplay between OGT and the homeostasis of the endolysosomal network in human cells.
Topics: Humans; N-Acetylglucosaminyltransferases; Autophagy; Endosomes; Down-Regulation; Lysosomes; rab7 GTP-Binding Proteins; Nutrients; rab GTP-Binding Proteins; Colon; HCT116 Cells; Autophagosomes
PubMed: 38852504
DOI: 10.1016/j.bbrc.2024.150198 -
International Journal of Biological... Jun 2024Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive pulmonary disease with an unclear pathogenesis and no available specific drug treatment. The principal...
Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive pulmonary disease with an unclear pathogenesis and no available specific drug treatment. The principal etiological factors are lung inflammation caused by environmental factors, damage to alveolar epithelial cells, leading to epithelial-mesenchymal transition (EMT), and the abnormal proliferation of fibroblasts. Here, we have demonstrated that fibroblast growth factor 21 (FGF21) ameliorates IPF via the autophagy pathway. We administered FGF21 to bleomycin (BLM)-treated mice, which ameliorated their defects in lung function, reduced the accumulation of collagen, restored tissue structure, reduced the deposition of hydroxyproline, reduced the expression of collagen I and α-SMA and increased the expression of E-cadherin. The expression of LC3BII and the number of autophagosomes were significantly higher in the lungs. The expression of AKT and mTOR was significantly reduced by FGF21 treatment. We also determined the effects of FGF21 in A549 cells treated with TGF-β, and found that FGF21 significantly inhibits activation of the AKT signaling pathway, thereby reducing TGF-β-induced EMT and preventing the uncontrolled proliferation of fibroblasts. We conclude that FGF21 ameliorates IPF by inhibiting the PI3K-AKT-mTOR signaling pathway and activating autophagy, which provides a theoretical basis for FGF21 to be used for the treatment of IPF.
PubMed: 38851619
DOI: 10.1016/j.ijbiomac.2024.132896 -
Nature Structural & Molecular Biology Jun 2024The hallmark of non-selective autophagy is the formation of cup-shaped phagophores that capture bulk cytoplasm. The process is accompanied by the conjugation of LC3B to...
The hallmark of non-selective autophagy is the formation of cup-shaped phagophores that capture bulk cytoplasm. The process is accompanied by the conjugation of LC3B to phagophores by an E3 ligase complex comprising ATG12-ATG5 and ATG16L1. Here we combined two complementary reconstitution approaches to reveal the function of LC3B and its ligase complex during phagophore expansion. We found that LC3B forms together with ATG12-ATG5-ATG16L1 a membrane coat that remodels flat membranes into cups that closely resemble phagophores. Mechanistically, we revealed that cup formation strictly depends on a close collaboration between LC3B and ATG16L1. Moreover, only LC3B, but no other member of the ATG8 protein family, promotes cup formation. ATG16L1 truncates that lacked the C-terminal membrane binding domain catalyzed LC3B lipidation but failed to assemble coats, did not promote cup formation and inhibited the biogenesis of non-selective autophagosomes. Our results thus demonstrate that ATG16L1 and LC3B induce and stabilize the characteristic cup-like shape of phagophores.
PubMed: 38834913
DOI: 10.1038/s41594-024-01300-y