OBJECTIVE: To explore the regulatory mechanism of human hepatocyte apoptosis induced by lysosomal membrane protein Sidt2 knockout. METHODS: The Sidt2 knockout (Sidt2^-/-) cell model was constructed in human hepatocyte HL7702 cells using Crispr-Cas9 technology.The protein levels of Sidt2 and key autophagy proteins LC3-II/I and P62 in the cell model were detected using Western blotting, and the formation of autophagosomes was observed with MDC staining.EdU incorporation assay and flow cytometry were performed to observe the effect of Sidt2 knockout on cell proliferation and apoptosis.The effect of chloroquine at the saturating concentration on autophagic flux, proliferation and apoptosis of Sidt2 knockout cells were observed. RESULTS: Sidt2^-/- HL7702 cells were successfully constructed.Sidt2 knockout significantly inhibited the proliferation and increased apoptosis of the cells, causing also increased protein expressions of LC3-II/I and P62(P < 0.05) and increased number of autophagosomes.Autophagy of the cells reached a saturated state following treatment with 50 μmol/L chloroquine, and at this concentration, chloroquine significantly increased the expressions of LC3B and P62 in Sidt2^-/- HL7702 cells. CONCLUSION Sidt2 gene knockout causes dysregulation of the autophagy pathway and induces apoptosis of HL7702 cells, and the latter effect is not mediated by inhibiting the autophagy-lysosomal pathway.
Humans ; Lysosome-Associated Membrane Glycoproteins/metabolism* ; Autophagy ; Apoptosis ; Hepatocytes ; Lysosomes/metabolism* ; Chloroquine/pharmacology* ; Nucleotide Transport Proteins/metabolism*

Objective: To review the clinical data of 7 patients with Danon disease and analyze their clinical characteristics. Methods: The medical records of 7 patients with Danon disease, who were hospitalized in Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from April 2008 to July 2021, were reviewed and summarized, of which 6 cases were diagnosed as Danon disease by lysosomal-associated membrane protein-2 (LAMP-2) gene mutation detection and 1 case was diagnosed by clinicopathological features. Clinical manifestations, biochemical indexes, electrocardiogram, echocardiography, skeletal muscle and myocardial biopsy and gene detection results were analyzed, and patients received clinical follow-up after discharge. Results: Six patients were male and average age was (15.4±3.5) years and the average follow-up time was (27.7±17.0) months. The main clinical manifestations were myocardial hypertrophy (6/7), decreased myodynamia (2/7) and poor academic performance (3/7). Electrocardiogram features included pre-excitation syndrome (6/7) and left ventricular hypertrophy (7/7). Echocardiography examination evidenced myocardial hypertrophy (6/7), and left ventricular dilatation and systolic dysfunction during the disease course (1/7). The results of skeletal muscle biopsy in 6 patients were consistent with autophagy vacuolar myopathy. Subendocardial myocardial biopsy was performed in 3 patients, and a large amount of glycogen deposition with autophagosome formation was found in cardiomyocytes. LAMP-2 gene was detected in 6 patients, and missense mutations were found in all these patients. During the follow-up period, implantable cardioverter defibrillator implantation was performed in 1 patient because of high atrioventricular block 4 years after diagnosis, and there was no death or hospitalization for cardiovascular events in the other patients. Conclusion: The main clinical manifestations of Danon disease are cardiomyopathy, myopathy and mental retardation. Pre-excitation syndrome is a common electrocardiographic manifestation. Autophagy vacuoles can be seen in skeletal muscle and myocardial pathological biopsies. LAMP-2 gene mutation analysis is helpful in the diagnose of this disease.
Adolescent ; Child ; Female ; Humans ; Male ; Cardiomyopathies/etiology* ; Glycogen Storage Disease Type IIb/complications* ; Hypertrophy, Left Ventricular/etiology* ; Lysosomal-Associated Membrane Protein 2/genetics* ; Pre-Excitation Syndromes/genetics*

Cancer stem cell-like cells (CSCs) play an integral role in the heterogeneity, metastasis, and treatment resistance of head and neck squamous cell carcinoma (HNSCC) due to their high tumor initiation capacity and plasticity. Here, we identified a candidate gene named LIMP-2 as a novel therapeutic target regulating HNSCC progression and CSC properties. The high expression of LIMP-2 in HNSCC patients suggested a poor prognosis and potential immunotherapy resistance. Functionally, LIMP-2 can facilitate autolysosome formation to promote autophagic flux. LIMP-2 knockdown inhibits autophagic flux and reduces the tumorigenic ability of HNSCC. Further mechanistic studies suggest that enhanced autophagy helps HNSCC maintain stemness and promotes degradation of GSK3β, which in turn facilitates nuclear translocation of β-catenin and transcription of downstream target genes. In conclusion, this study reveals LIMP-2 as a novel prospective therapeutic target for HNSCC and provides evidence for a link between autophagy, CSC, and immunotherapy resistance.
Humans ; Autophagy ; Carcinoma, Squamous Cell/pathology* ; Cell Line, Tumor ; Glycogen Synthase Kinase 3 beta/metabolism* ; Head and Neck Neoplasms/pathology* ; Neoplastic Stem Cells/pathology* ; Squamous Cell Carcinoma of Head and Neck/pathology* ; Lysosome-Associated Membrane Glycoproteins

OBJECTIVE: To investigate the relationship between the expression of lysosomal membrane proteins LAMP1, TPC1 and TPC2 in acute myeloid leukemia (AML) cells and clinical indications of AML and to explore the possible role in the genesis and development of AML and clinical significance. METHODS: Real-time quantitative PCR was used to detect the mRNA expression of LAMP1, TPC1 and TPC2 in AML cell lines (HL-60, NB4) and 57 patients with acute myeloid leukemia (including 44 initially treated patients and 13 relapsed and refractory patients). The relationship of mRNA expression levels with clinical indicators and post-chemotherapy remission was analyzed. RESULTS: Compared with CD34 hematopoietic stem cells (HSC), the expression levels of LAMP1 and TPC1 in AML cell lines HL-60 and NB4 significantly increased, while the expression level of TPC2 was not significantly different. The expression levels of LAMP1, TPC1 and TPC2 in bone marrow mononuclear cells (BMMNC) of AML patients were higher than those in normal human BMMNC (P<0.05), and the expression levels of LAMP1, TPC1 and TPC2 in CD34 primary AML cells(CD34 primary cells in the patient's bone marrow >90%) were also high. There was no significant difference in the expression of LAMP1, TPC1 and TPC2 between CD34HSC of patients with AML and relapsed/refractory patients (P>0.05). No correlation was found between age, sex and genotype and expression of membrane proteins (P>0.05). The expression levels of LAMP1 and TPC1 positively correlated with the number of white blood cells in peripheral blood of patients (P<0.01). LAMP1 and TPC2 were found to be associated with remission after a course of chemotherapy in newly diagnosed patients. Initially treated patients with high expression of LAMP1 in the bone marrow not easily relieved after one course of chemotherapy. Patients with high expression of TPC2 in the bone marrow more likely to be relieved after one course of chemotherapy. CONCLUSION The mRNA of the three membrane proteins are highly expressed in AML patients, and LAMP1 and TPC1 are risk factors for AML disease progression. High expression of TPC2 is beneficial for chemotherapy of patients with newly diagnosed AML.
Bone Marrow ; Bone Marrow Cells ; Hematopoietic Stem Cells ; Humans ; Leukemia, Myeloid, Acute ; Lysosome-Associated Membrane Glycoproteins

OBJECTIVE: To investigate the effect of estradiol (E2)/estrogen receptor 1 (ESR1) on the proliferation of human chondrocytes and explore the molecular mechanism. METHODS: The Ad-Easy adenovirus packaging system was used to construct and package the ESR1-overexpressing adenovirus Ad-ESR1. Western blotting and qPCR were used to detect the expression of ESR1 protein and mRNA in human chondrocyte C28I2 cells. In the cells treated with different adenoviruses, the effects of E2 were tested on the expressions of proteins related with cell autophagy and apoptosis and the phosphorylation of ERK signaling pathway using Western blotting. Immunofluorescence assay was used to observe the intracellular autophagic flow, flow cytometry was performed to analyze the cell apoptosis rate and the cell cycle changes, and qPCR was used to detect the expressions of PCNA, cyclin B1 and cyclin D1 mRNAs. The inhibitory effect of the specific inhibitor of ERK on the expressions of autophagy- and apoptosis-related genes at both the protein and mRNA levels were detected using Western blotting and qPCR. RESULTS: Transfection with the recombinant adenovirus overexpressing ESR1 and E2 treatment of C28I2 cells significantly enhanced the expressions of autophagy-related proteins LC3, ATG7, promoted the colocalization of LC3 and LAMP1 in the cytoplasm, increased the expressions of the proliferation-related marker genes PCNA, cyclin B1 and cyclin D1, and supressed the expressions of cleaved caspase-3, caspase-12 and pERK. RNA interference of ESR1 obviously lowered the expression levels of autophagy-related proteins in C28I2 cells, causing also suppression of the autophagic flow, increments of the expressions of apoptosis-related proteins and pERK, and down-regulated the expressions of the proliferation marker genes. Blocking ERK activation with the ERK inhibitor obviously inhibited the effects of E2/ESR1 on autophagy, proliferationrelated gene expressions and cell apoptosis. CONCLUSIONS The targeted binding of E2 with ESR1 promotes the proliferation of human chondrocytes possibly by inhibiting the activation of ERK signaling pathway to promote cell autophagy and induce cell apoptosis.
Adenoviridae ; metabolism ; Apoptosis ; Autophagy ; Autophagy-Related Protein 7 ; metabolism ; Cell Line ; Cell Proliferation ; Chondrocytes ; cytology ; metabolism ; Estradiol ; metabolism ; Estrogen Receptor alpha ; metabolism ; Humans ; Lysosome-Associated Membrane Glycoproteins ; metabolism ; MAP Kinase Signaling System ; Microtubule-Associated Proteins ; metabolism ; Transfection

ObjectiveRapid eye movement sleep behavior disorder (RBD) is characterized by dream enactment and loss of muscle atonia during rapid eye movement sleep. RBD is closely related to α-synucleinopathies including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Many studies have investigated the markers of imaging and neurophysiological, genetic, cognitive, autonomic function of RBD and their predictive value for neurodegenerative diseases. This report reviewed the progress of these studies and discussed their limitations and future research directions.

Data SourcesUsing the combined keywords: "RBD", "neurodegenerative disease", "Parkinson disease", and "magnetic resonance imaging", the PubMed/MEDLINE literature search was conducted up to January 1, 2018.

Study SelectionA total of 150 published articles were initially identified citations. Of the 150 articles, 92 articles were selected after further detailed review. This study referred to all the important English literature in full.

ResultsSingle-nucleotide polymorphisms in SCARB2 (rs6812193) and MAPT (rs12185268) were significantly associated with RBD. The olfactory loss, autonomic dysfunction, marked electroencephalogram slowing during both wakefulness and rapid eye movement sleep, and cognitive impairments were potential predictive markers for RBD conversion to neurodegenerative diseases. Traditional structural imaging studies reported relatively inconsistent results, whereas reduced functional connectivity between the left putamen and substantia nigra and dopamine transporter uptake demonstrated by functional imaging techniques were relatively consistent findings.

ConclusionsMore longitudinal studies should be conducted to evaluate the predictive value of biomarkers of RBD. Moreover, because the glucose and dopamine metabolisms are not specific for assessing cognitive cognition, the molecular metabolism directly related to cognition should be investigated. There is a need for more treatment trials to determine the effectiveness of interventions of RBD on preventing the conversion to neurodegenerative diseases.

Biomarkers ; blood ; Humans ; Lysosome-Associated Membrane Glycoproteins ; genetics ; Neurodegenerative Diseases ; blood ; genetics ; physiopathology ; Parkinson Disease ; blood ; genetics ; physiopathology ; Polymorphism, Single Nucleotide ; genetics ; REM Sleep Behavior Disorder ; blood ; genetics ; physiopathology ; Receptors, Scavenger ; genetics ; tau Proteins ; genetics

X-linked dominant mutations in lysosome-associated membrane protein 2 (LAMP2) gene have been shown to be the cause of Danon disease, which is a rare disease associated with clinical triad of cardiomyopathy, skeletal myopathy, and mental retardation. Cardiac involvement is a common manifestation and is the leading cause of death in Danon disease. We report a case of a 24-month-old boy with hemizygous LAMP2 mutation who presented with failure to thrive and early-onset hypertrophic cardiomyopathy. We applied targeted exome sequencing and found a novel hemizygous c.692del variant in exon 5 of the LAMP2 gene, resulting a frameshift mutation p.Thr231Ilefs*11. Our study indicates that target next-generation sequencing can be used as a fast and highly sensitive screening method for inherited cardiomyopathy.
Cardiomyopathies ; Cardiomyopathy, Hypertrophic* ; Cause of Death ; Child, Preschool ; Exome* ; Exons ; Failure to Thrive ; Frameshift Mutation ; Glycogen Storage Disease Type IIb ; Humans ; Intellectual Disability ; Lysosomal-Associated Membrane Protein 2 ; Male ; Mass Screening ; Membrane Proteins ; Methods ; Muscular Diseases ; Rare Diseases

Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.
Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; chemistry ; genetics ; metabolism ; Binding Sites ; Cell Line ; Crystallography, X-Ray ; Enterovirus A, Human ; drug effects ; genetics ; growth & development ; immunology ; Fibroblasts ; drug effects ; virology ; Gene Expression ; HEK293 Cells ; Humans ; Immunoglobulin Fab Fragments ; chemistry ; genetics ; metabolism ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; immunology ; Mice ; Models, Molecular ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Receptors, Scavenger ; chemistry ; genetics ; immunology ; Receptors, Virus ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Sequence Alignment ; Sequence Homology, Amino Acid ; Sf9 Cells ; Spodoptera ; Thermodynamics

OBJECTIVES: There have been developed to use targeting ability for antimicrobial, anticancerous, gene therapy and cosmetics through analysis of various membrane proteins isolated from cell organelles. METHODS: It was examined about the lysosomal membrane protein extracted from lysosome isolated from HeLa cell treated by 100 ppm melanin for 24 hours in order to find associated with targeting ability to melanin using by 2-dimensional electrophoresis. RESULTS: The result showed 14 up-regulated (1.5-fold) and 13 down-regulated (2.0-fold) spots in relation to melanin exposure. CONCLUSIONS: It has been found that lysosomal membrane proteins are associated with melanin to decolorize and quantity through cellular activation of lysosome.
Electrophoresis ; Genetic Therapy ; HeLa Cells* ; Humans ; Lysosome-Associated Membrane Glycoproteins* ; Lysosomes ; Melanins* ; Membrane Proteins ; Organelles

SCARB2 (scavenger receptor class B, member 2) is a lysosomal membrane glucoprotein, which is encoded by SCARB2 gene. It takes vital parts in the physiological and pathological processes including the transportation of beta-glucocerebrosidase to the lysosome, infection of EV71 and load-induced cardiac myocyte hypertrophy. This article has reviewed the molecular structure and functions of SCARB2 gene and its protein, as well as their relationship with diseases.
Hand, Foot and Mouth Disease ; genetics ; Humans ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; physiology ; Myoclonic Epilepsies, Progressive ; genetics ; Parkinson Disease ; genetics ; Receptors, Scavenger ; chemistry ; genetics ; physiology