Endosomal sorting complex required for transport (ESCRT) system drives various cellular processes, including endosome sorting, organelle biogenesis, vesicle transport, maintenance of plasma membrane integrity, membrane fission during cytokinesis, nuclear membrane reformation after mitosis, closure of autophagic vacuoles, and enveloped virus budding. Increasing evidence suggests that the ESCRT system can be hijacked by different family viruses for their proliferation. At different stages of the virus life cycle, viruses can interfere with or exploit ESCRT-mediated physiological processes in various ways to maximize their chance of infecting the host. In addition, many retroviral and RNA viral proteins possess "late domain" motifs, which can recruit host ESCRT subunit proteins to assist in virus endocytosis, transport, replicate, budding and efflux. Therefore, the "late domain" motifs of viruses and ESCRT subunit proteins could serve as promising drug targets in antiviral therapy. This review focuses on the composition and functions of the ESCRT system, the effects of ESCRT subunits and virus "late domain" motifs on viral replication, and the antiviral effects mediated by the ESCRT system, aiming to provide a reference for the development and utilization of antiviral drugs.
Endosomal Sorting Complexes Required for Transport/metabolism* ; Viruses/metabolism* ; Protein Transport ; Virus Replication ; Endosomes/metabolism* ; Virus Release

The endosomal sorting complexes required for transport (ESCRTs) regulate protein trafficking from endosomes to lysosomes. Recent studies have shown that ESCRTs are involved in various cellular processes, including membrane scission, microRNA function, viral budding, and the autophagy pathway in many tissues, including the nervous system. Indeed, dysfunctional ESCRTs are associated with neurodegeneration. However, it remains largely elusive how ESCRTs act in post-mitotic neurons, a highly specialized cell type that requires dynamic changes in neuronal structures and signaling for proper function. This review focuses on our current understandings of the functions of ESCRTs in neuronal morphology, synaptic plasticity, and neurodegenerative diseases.
Autophagy ; Dendrites ; Endocytosis ; Endosomal Sorting Complexes Required for Transport ; Endosomes ; Lysosomes ; Membranes ; MicroRNAs ; Nervous System ; Neurodegenerative Diseases ; Neurons ; Plastics ; Protein Transport

In eukaryotic cells, multivesicular bodies (MVBs) are required for trafficking of membrane proteins to lysosomes for selective destruction. The sorting of ubiquitylated membrane proteins into multivesicular bodies and the biogenesis of MVBs are mediated by the endosomal sorting complex required for transport (ESCRT). Topologically equivalent to the budding of intralumenal vesicles from the limiting membrane of the MVBs, the ESCRT complex is also involved in cytokinetic abscission, phagophore formation, and enveloped virus budding. Many retroviruses and RNA viruses encode "late-domain" motifs that are able to interact with the components of the ESCRT complex, and the interactions recruit ESCRT-III and VPS4 to the viral assembly and budding sites. Recently, few studies revealed that the ESCRT complex is also required for efficient egress of some DNA viruses, including Hepatitis B, Herpes simplex virus type-1, and Autographa californica multiple nucleopolyhedrovirus. Further examination of virus-ESCRT interactions should shed light on the detailed mechanism of virus assembly and budding.
Endosomal Sorting Complexes Required for Transport ; physiology ; Humans ; Viral Envelope Proteins ; metabolism ; Virus Assembly ; Virus Physiological Phenomena ; Virus Release ; Viruses ; growth & development

OBJECTIVES: The effect of Vps4b gene mutation on the expressions of cytokeratin 14 (CK14) and proliferating cell nuclear antigen (PCNA) in the Hertwig's epithelial root sheath (HERS) is investigated. METHODS: The bilateral mandibular tissues of mouse on postnatal days 5, 9, 11, 15, and 19 were removed. The mandibular first molar tissue sections were obtained after paraffin embedding. The CK14 and PCNA expressions in the epithelial root sheath of the normal mouse and Vps4b knockout mouse were compared through immunohistochemistry. RESULTS: On postnatal day 5, the normal mouse began to form HERS and had a strong positive PCNA expression in the HERS cells; on postnatal day 9, the HERS structure was continuous, and PCNA was positive in the HERS cells; on postnatal day 11, a small portion of HERS began to break, and PCNA was weakly positive in the HERS cells; on postnatal day 15, HERS continued to fracture; PCNA was weakly and positively expressed in the HERS cells on the root surface; on postnatal day 19, the tooth root reached normal physiological length, and PCNA was positively expressed in the HERS cells of the terminal part. Similar to the normal mouse, the gene knockout mouse also formed a HERS structure on postnatal day 5. However, HERS began to break on postnatal day 9. On postnatal day 19, only a few fragments of HERS were found on the root surface, and the root development was immature. Moreover, the expression intensity of PCNA in the gene knockout mouse was decreased. CONCLUSIONS The Vps4b gene mutation may change the CK14 and PCNA expressions, leading to abnormal root development.
ATPases Associated with Diverse Cellular Activities ; Animals ; Endosomal Sorting Complexes Required for Transport ; Epithelial Cells ; Keratin-14 ; Mice ; Mice, Knockout ; Proliferating Cell Nuclear Antigen ; Tooth Root

OBJECTIVETo analyze the association between the genetic variations of functional region in neural precursor cell expressed developmentally down-regulated 4 ( NEDD4) gene and hypertension in Kazak Chinese in Xinjiang Uygur Autonomous Region.

METHODSThe sequences of NEDD4 gene functional region (all exons, exon-intron boundaries, and the putative promoter region, including the 5'- and 3'-untranslated regions 1 kb) were sequenced in Kazak Chinese patients with hypertension. The representative variations selected were genotyped by TaqMan-PCR method in 938 Kazak individuals, including 451 hypertensive patients and 487 normotensive subjects. The association between genetic variations of NEDD4 and hypertension in Kazak was analyzed.

RESULTSThirteen novel and 15 known single nucleotide polymorphism (SNPs) or mutations, including 7 missense mutations, were identified at the function region of NEDD4 gene in 94 Kazak patients with hypertension. In the nine representative variations genotyped, 4 rare missense mutations [77291T>G (S189R), 77748 C>T (R342W), 123925C>T (P152L), rs1912403 (76821A>G, M33V)] were not specific for the prevalence of hypertension; in addition, the distribution of 5 common SNPs [77943A>C (N407H), rs2303580 (132882G>A, R607Q), rs8028559 (154845T>C), rs7162435 (164420A>G), and rs11550869 (165622C>G)] and haplotypes were not significantly different between the hypertensive patients and normotensive subjects (P>0.05).

CONCLUSIONThe NEDD4 gene polymorphisms is no associated with hypertension in Kazak Chinese population.

Adult ; Aged ; Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; China ; Endosomal Sorting Complexes Required for Transport ; genetics ; Female ; Humans ; Hypertension ; genetics ; Male ; Middle Aged ; Minority Groups ; Nedd4 Ubiquitin Protein Ligases ; Polymorphism, Genetic ; Ubiquitin-Protein Ligases ; genetics

OBJECTIVETo study the feasibility of using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) for the detection of DNA methylation in placenta tissue.

METHODSFor blood cells from 13 non-pregnant women and 9 euploid placenta, the ratios of DNA methylation were evaluated for 4 genes including CGI149, CGI113, HLCS and ACTB with MS-MLPA and bisulfite sequencing, respectively.

RESULTSThe methylation ratio of the ACTB gene was 0-0.1 for the blood cells when the digestion control was completely digested. The cutoff value for the methylation ratio of MS-MLPA has been determined as 0.1. For the 9 placenta samples, results of MS-MLPA and bisulfite sequencing were concordant for all of the four genes.

CONCLUSIONMS-MLPA is an effective alternative to bisulfite sequencing for the assessment of methylation ratios in placental tissues.

Actins ; genetics ; Adult ; Carbon-Nitrogen Ligases ; genetics ; CpG Islands ; genetics ; DNA Methylation ; Endosomal Sorting Complexes Required for Transport ; genetics ; Feasibility Studies ; Female ; Humans ; Multiplex Polymerase Chain Reaction ; methods ; Placenta ; metabolism ; Pregnancy ; Reproducibility of Results ; Ribosomal Proteins ; genetics ; Young Adult

This study examined the anti-hepatitis B virus (HBV) effect of wild-type (WT) vacuolar protein sorting 4B (VPS4B) and its dominant negative (DN) mutant VPS4B-K180Q in vivo in order to further explore the relationship between HBV and the host cellular factor VPS4. VPS4B gene was amplified from Huh7 cells by RT-PCR and cloned into the eukaryotic expression vector pXF3H. Then, the VPS4B plasmid and the VPS4B-K180Q mutation plasmid were constructed by using the overlap extension PCR site-directed mutagenesis technique. VPS4B and HBV vectors were co-delivered into mice by the hydrodynamic tail-vein injection to establish HBV vector-based models. Quantities of HBsAg and HBeAg in the mouse sera were determined by ElectroChemiLuminescence (ECL). HBV DNA in sera was measured by real-time quantitative PCR. Southern blot analysis was used to assay the intracellular HBV nuclear capsid-related DNA, real-time quantitative PCR to detect the HBV-related mRNA and immunohistochemical staining to observe the HBcAg expression in the mouse liver tissues. Our results showed that VPS4B and its mutant VPS4B-K180Q could decrease the levels of serum HBsAg, HBeAg and HBV-DNA. In addition, the HBV DNA replication and the mRNA level of HBV in the liver tissues of treated mice could be suppressed by VPS4B and VPS4B-K180Q. It was also found that VPS4B and VPS4B-K180Q had an ability to inhibit core antigen expression in the infected mouse liver. Furthermore, the anti-HBV effect of mutant VPS4B-K180Q was more potent than that of wild-type VPS4B. Taken together, it was concluded that VPS4B and its DN mutant VPS4B-K180Q have anti-HBV effect in vivo, which helps develop molecular therapeutic strategies for HBV infection.
ATPases Associated with Diverse Cellular Activities ; Adenosine Triphosphatases ; physiology ; Animals ; Endosomal Sorting Complexes Required for Transport ; physiology ; Female ; Genes, Dominant ; genetics ; Hepatitis B ; metabolism ; virology ; Hepatitis B virus ; physiology ; Liver ; virology ; Mice ; Mice, Inbred BALB C ; Mutation ; genetics ; Virus Inactivation

A splicing mutation in VPS4B can cause dentin dysplasia type I (DD-I), a hereditary autosomal-dominant disorder characterized by rootless teeth, the etiology of which is genetically heterogeneous. In our study, dental follicle cells (DFCs) were isolated and cultured from a patient with DD-I and compared with those from an age-matched, healthy control. In a previous study, this DD-I patient was confirmed to have a loss-of-function splicing mutation in VPS4B (IVS7 + 46C > G). The results from this study showed that the isolated DFCs were vimentin-positive and CK14-negative, indicating that the isolated cells were derived from the mesenchyme. DFCs harboring the VPS4B mutation had a significantly higher proliferation rate from day 3 to day 8 than control DFCs, indicating that VPS4B is involved in cell proliferation. The cells were then replenished with osteogenic medium to investigate how the VPS4B mutation affected osteogenic differentiation. Induction of osteogenesis, detected by alizarin red and alkaline phosphatase staining in vitro, was decreased in the DFCs from the DD-I patient compared to the control DFCs. Furthermore, we also found that the VPS4B mutation in the DD-I patient downregulated the expression of osteoblast-related genes, such as ALP, BSP, OCN, RUNX2, and their encoded proteins. These outcomes confirmed that the DD-I-associated VPS4B mutation could decrease the capacity of DFCs to differentiate during the mineralization process and may also impair physiological root formation and bone remodeling. This might provide valuable insights and implications for exploring the pathological mechanisms underlying DD-I root development.
ATPases Associated with Diverse Cellular Activities ; genetics ; Case-Control Studies ; Cell Differentiation ; genetics ; Cells, Cultured ; Dental Sac ; cytology ; Dentin Dysplasia ; genetics ; pathology ; physiopathology ; Endosomal Sorting Complexes Required for Transport ; genetics ; Humans ; Mutation ; genetics ; Osteogenesis ; genetics ; RNA Splicing ; genetics

OBJECTIVE: To study whether TGF-α possesses similar EGF effect of enforcing neuroendocrine differentiation (NED) in prostate cancer cell line DU145 and determine the influence of NED induced by TGF-α on chemoresistance. METHODS: DU145 cells were divided into 3 groups: a group with 2% FBS, a group with 2%FBS+TGF-α 5 ng/mL and a group with 2%FBS+TGF-α 10 ng/mL. Morphological change in DU145 cells was observed after TGF-α treatment. Expression levels of NSE mRNA were detected with real time RT-PCR. Western blot was used to detect the expression levels of protein NSE, P-gp, MRP1 and Bcl-2. Cell cycles of DU145 cells in the 3 groups were examined with flow cytometry. MTT assay was used to evaluate the influence of TGF-α in chemoresistance. RESULTS: Compared with DU145 cells cultured with 2% FBS, cells treated with 2% FBS+TGF-α were pleomorphic and pseudopodia extended. The expression level of NSE mRNA upregulated to (3.6±0.5) folds (P<0.05) and (10.1±0.1) folds (P<0.01). Western blot showed that the expression levels of protein NSE, Bcl-2, and MRP1 increased after treatment with different concentrations of TGF-α; P-gp was not detected. The proportion of DU145 cells in phase G1 decreased; proportions of cells in phase S and phase G2/M were increased after TGF-α treatment (5 μg/mL). At the same time, chemoresistance of DU145 cells to cisplatin increased. CONCLUSION TGF-α can increase NED in DU145 cells and enforce the chemoresistance to cisplatin.
Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Drug Resistance, Neoplasm ; drug effects ; Endosomal Sorting Complexes Required for Transport ; pharmacology ; Humans ; Male ; Prostatic Neoplasms ; metabolism ; pathology ; Transforming Growth Factor alpha ; pharmacology

OBJECTIVE: To verify the effect of the mutant gene vps4b on the expression of tooth development-related proteins, dentin sialophosphoprotein (DSPP) and collagenⅠ (COL-Ⅰ). METHODS: Paraffin tissue sections of the first molar tooth germ were obtained from the heads of fetal mice at the embryonic stages of 13.5, 14.5, and 16.5 days and from the mandibles of larvae aged 2.5 and 7 days after birth. The immunohistochemical method was used to detect the expression and location of DSPP and COL-Ⅰ in wild-type mouse and vps4b knockout mouse. RESULTS: DSPP and COL-Ⅰ were not found in the bud and cap stages of wild-type mouse molar germ. In the bell stage, DSPP was positively expressed in the inner enamel epithelium and dental papilla, whereas COL-Ⅰ was strongly expressed in the dental papilla and dental follicle. During the secretory and mineralized periods, DSPP and COL-Ⅰ were intensely observed in ameloblasts, odontoblasts, and dental follicles, but COL-Ⅰ was also expressed in the dental papilla. After vps4b gene knockout, DSPP was not expressed in the dental papilla of the bell stage and in the dental papilla and dental follicle of the secretory phase. The expression position of COL-Ⅰ in the bell and mineralization phase was consistent with that in the wild-type mice. Moreover, the expression of COL-Ⅰ in the dental papilla changed in the secretory stage. CONCLUSIONS Gene vps4b plays a significant role in the development of tooth germ. The expression of DSPP and COL-Ⅰ may be controlled by gene vps4b and regulates the development of tooth dentin and cementum together with vps4b.
ATPases Associated with Diverse Cellular Activities ; genetics ; Animals ; Collagen ; metabolism ; Endosomal Sorting Complexes Required for Transport ; genetics ; Extracellular Matrix Proteins ; metabolism ; Mice ; Mice, Knockout ; Molar ; Odontoblasts ; Phosphoproteins ; metabolism ; Sialoglycoproteins ; metabolism ; Tooth Germ