OBJECTIVE: X-linked myopathy with excessive autophagy (XMEA) linked to the VMA21 gene leads to autophagy failure with progressive vacuolation and atrophy of skeletal muscles. Current knowledge of this rare disease is limited. Our objective was to define the clinical, radiological, and natural history of XMEA.
METHODS: We conducted a retrospective study collecting clinical, genetic, muscle imaging, and biopsy data of XMEA patients followed in France and reviewed the literature for additional cases.
RESULTS: Eighteen males had genetically confirmed XMEA in France, carrying four different VMA21 variants. Mean age at disease onset was 9.4 ± 9.9 (range 1-40) years. In 14/18 patients (77.8%), onset occurred during childhood (< 15 years); however in four patients, the disease started in adulthood. Patients had anterior and medial compartment thigh muscle weakness, distal contractures (56.3%), elevated CK levels (1287.9 ± 757.8 U/l) and autophagic vacuoles with sarcolemmal features on muscle histopathology. Muscle MRI (n = 10) showed a characteristic pattern of lower limb muscle involvement. In 11 patients, outcome measures were available for an average follow-up period of 10.6 ± 9.8 years and six of them show disease progression. Mean change of functional outcomes was 0.5 ± 1.2 points for Brooke and 2.2 ± 2.5 points for Vignos score, 7/16 patients (43.8%) needed a walking aid and 3/16 (18.8%) were wheelchair-bound (median age of 40 years old, range 39-48). The variant c.164-7 T > G was associated with a later onset of symptoms. Respiratory insufficiency was common (57.1%) but cardiac involvement rare (12.5%).
CONCLUSIONS: XMEA has variable age of onset, but a characteristic clinical, histopathological, and muscle imaging presentation, guiding the diagnosis. Although slowly, motor disability progresses with time, and relevant genotype-phenotype correlations will help design future clinical trials.

Defective lysosomal acidification is responsible for a large range of multi-systemic disorders associated with impaired autophagy. Diseases caused by mutations in the VMA21 gene stand as exceptions, specifically affecting skeletal muscle (X-linked Myopathy with Excessive Autophagy, XMEA) or liver (Congenital Disorder of Glycosylation). VMA21 chaperones vacuolar (v-) ATPase assembly, which is ubiquitously required for proper lysosomal acidification. The reason VMA21 deficiencies affect specific, but divergent tissues remains unknown. Here, we show that VMA21 encodes a yet-unreported long protein isoform, in addition to the previously described short isoform, which we name VMA21-120 and VMA21-101, respectively. In contrast to the ubiquitous pattern of VMA21-101, VMA21-120 was predominantly expressed in skeletal muscle, and rapidly up-regulated upon differentiation of mouse and human muscle precursors. Accordingly, VMA21-120 accumulated during development, regeneration and denervation of mouse skeletal muscle. In contrast, neither induction nor blockade of autophagy, in vitro and in vivo, strongly affected VMA21 isoform expression. Interestingly, VMA21-101 and VMA21-120 both localized to the sarcoplasmic reticulum of muscle cells, and interacted with the v-ATPase. While VMA21 deficiency impairs autophagy, VMA21-101 or VMA21-120 overexpression had limited impact on autophagic flux in muscle cells. Importantly, XMEA-associated mutations lead to both VMA21-101 deficiency and loss of VMA21-120 expression. These results provide important insights into the clinical diversity of VMA21-related diseases and uncover a muscle-specific VMA21 isoform that potently contributes to XMEA pathogenesis.

X-linked Myopathy with Excessive Autophagy (XMEA) is a rare autophagic vacuolar myopathy caused by mutations in the Vacuolar ATPase assembly factor VMA21 gene; onset usually occurs during childhood and rarely occurs during adulthood. We described a 22-year-old patient with XMEA, whose onset was declared at 11 through gait disorder. He had severe four-limb proximal weakness and amyotrophy, and his proximal muscle MRC score was between 2 and 3/5 in four limbs; creatine kinase levels were elevated (1385 IU/L), and electroneuromyography and muscle MRI were suggestive of myopathy. Muscle biopsy showed abnormalities typical of autophagic vacuolar myopathy. We detected a hemizygous, unreported, intronic, single-nucleotide substitution c.164-20T>A (NM_001017980.4) in intron 2 of the VMA21 gene. Fibroblasts derived from this patient displayed a reduced level of VMA21 transcripts (at 40% of normal) and protein, suggesting a pathogenicity related to an alteration of the splicing efficiency associated with an intron retention. This patient with XMEA displayed a severe phenotype (rapid weakness of upper and lower limbs) due to a new intronic variant of VMA21, related to an alteration in the splicing efficiency associated with intron retention, suggesting that phenotype severity is closely related to the residual expression of the VMA21 protein.

Circular RNA derived from vacuolar ATPase assembly factor (VMA21) has been proven to be an inflammation suppressor in many diseases, while its role in osteoarthritis (OA) is unknown. We predicted that VMA21 participates in OA via interacting with miR-103, an OA promoter. Therefore, we analyzed the crosstalk between VMA21 and miR-103 in OA. In this study, the levels of VMA21, pre-miR-103, and mature miR-103 in synovial fluid samples from OA patients (n = 56) and controls (n = 56) were analyzed using RT-qPCR. Nuclear and cytoplasm samples were prepared from chondrocytes, and VMA21 expression was detected by RT-PCR. RNA-RNA pulldown assay was applied to analyze the direct interaction between VMA21 and pre-miR-103. The involvement of VMA21 and miR-103 in lipopolysaccharide (LPS)-induced chondrocyte apoptosis and viability was analyzed using cell apoptosis assay and 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, respectively. We found that compared to the control group, VMA21 expression was decreased in OA, and miR-103 maturation was increased in OA. VMA21 could be detected in both nuclear and cytoplasm, and VMA21 directly interacted with pre-miR-103. VMA21 overexpression reduced miR-103 maturation. VMA21 suppressed the role of miR-103 in enhancing chondrocyte apoptosis and reducing cell viability after LPS treatment. In conclusion, VMA21 might suppress LPS-induced chondrocyte apoptosis in OA by decreasing the production of mature miR-103.

Lung adenocarcinoma (LUAD) is a common subtype of lung cancer with high recurrence rate and fatality. Circ_0001361 has been recognized as key regulators in various malignancies, but its roles in LUAD remain ambiguous.
Circ_0001361, miR-525-5p, and VMA21 levels were assessed by RT-qPCR. The growth and metastasis of LUAD cells were detected by MTT, colony formation, wound scratch, and transwell assays, respectively. The interaction between circ_0001361/VMA21 and miR-525-5p was detected by dual luciferase, RNA immunoprecipitation, and RNA pull-down assays. VMA21 protein level was detected by Western blotting. Nude mouse xenograft model was established to determine the role of circ_0001361 in tumor growth in vivo.
Circ_0001361 was up-regulated, while miR-525-5p was down-regulated in LUAD tissues and cells. Functional experiments demonstrated that circ_0001361 drove LUAD cell growth and metastasis. Mechanistically, circ_0001361 functioned as a sponge of miR-525-5p to up-regulate downstream target VMA21 level. MiR-525-5p/VMA21 axis was involved in circ_0001361-mediated malignant phenotypes of LUAD cells. Finally, inhibition of circ_0001361 restrained in vivo xenograft tumor growth via regulating miR-525-5p/VMA21 axis.
Our findings elucidate that circ_0001361 facilitates the tumorigenesis and development of LUAD through miR-525-5p/VMA21 axis, providing evidence for circ_0001361 as a potential prognosis biomarker and therapeutic target for clinical treatment of LUAD.

X-linked myopathy with excessive autophagy (XMEA) is a rare disorder characterized by slow progressive muscle weakness and distinctive pathology of excessive autophagic vacuoles on muscle biopsy. Here we report on five patients, in a single family, with proximal lower limb weakness. The proband, a 25-year-old man, presented with 5 years of progressive lower limbs proximal muscle weakness. His maternal grandfather and three of his maternal male cousins had similar clinical findings and were initially suspected to have Becker muscular dystrophy. Muscle biopsy in two affected family members demonstrated autophagic myopathy, and guided the genetic investigations to the identification of a pathogenic mutation, c.272G > C in the VMA21 gene, known to cause XMEA [1]. To the best of our knowledge this is the first identified Israeli Jewish family afflicted by XMEA.

BACKGROUND: Cervical cancer (CC) is the most common form of gynecological malignancy. Long intergenic non-protein coding RNA 858 (LINC00858) has been identified to participate in multiple cancers. However, the role and mechanism of LINC00858 in CC cells are still elusive.
OBJECTIVE: The aim of this study is to explore the biological functions and mechanisms of LINC00858 in CC cells.
METHODS: RT-qPCR analysis was used to examine the expression of LINC00858 in CC cells. EdU and colony formation assay were utilized to assess cell proliferation. TUNEL assay and flow cytometry assay were conducted to assess cell apoptosis. The mechanism regarding LINC00858 was certified through RNA pull down, RIP and luciferase reporter assays.
RESULTS: The up-regulated LINC00858 was detected in CC cells. Reduction of LINC00858 effectively subdued CC cells proliferation and stimulated cell apoptosis. LINC00858 was determined to bind with miR-3064-5p and up-regulate VMA21 in CC cells. In rescue assays, miR-3064-5p down-regulation and VMA21 up-regulation were able to counteract the effect caused by LINC00858 decrease on CC cell proliferation and apoptosis.
CONCLUSIONS: LINC00858 enhances cell proliferation, while restraining cell apoptosis in CC through targeting miR-3064-5p/VMA21 axis, implying that LINC00858 may serve as a promising therapeutic target for CC.

Melanoma is an aggressive malignant skin tumor endangering the health of patients. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been increasingly reported to be implicated in the carcinogenesis of melanoma. Long intergenic non-coding RNA 00665 (LINC00665) has been found to exert important regulatory roles in some cancers, yet its function in melanoma remains to be investigated. QRT-PCR analysis was conducted to evaluate the relative expression of RNAs. Functional experiments in vitro including colony formation, EdU, wound-healing and transwell assays, as well as in vivo xenograft assays, were utilized to study the role of LINC00665 in melanoma. Mechanical experiments were implemented to probe into the molecular linkage of LINC00665, miR-224-5p and VMA21. LINC00665 was abnormally highly expressed in melanoma cells. Silencing LINC00665 could inhibit the proliferation and migration of melanoma cells. LINC00665 sponged miR-224-5p to upregulate VMA21. VMA21 knockdown exerted similarly interfering effects on above biological processes in melanoma cells. However, VMA21 overexpression abolished the in vitro and in vivo outcomes of LINC00665 silencing. LINC00665 promotes proliferative and migrating abilities of melanoma cells via targeting miR-224-5p/VMA21 axis.

暂无摘要。

Lung cancer has been proved to be one of the most common kinds of cancers around the globe. Meanwhile, as the predominant type of lung cancer, lung adenocarcinoma (LUAD) has received increasing attention in cancer research. Long noncoding RNAs (lncRNAs) are known to be associated with oncogenesis and progression of various cancers. However, many lncRNAs have not been thoroughly detected in LUAD. In this study, through bioinformatics analysis we found that zinc finger protein multitype 2 antisense RNA 1 (ZFPM2-AS1) was associated with poor prognosis of LUAD patients. Also, ZFPM2-AS1 was detected to be overexpressed in LUAD tissues and cells. Furthermore, ZFPM2-AS1 could promote the proliferation of LUAD cells. Next, miR-18b-5p was found to bind with and negatively regulated by ZFPM2-AS1. VMA21, target gene of miR-18b-5p, could bind with and be negatively regulated by miR-18b-5p. More importantly, both ZFPM2-AS1 and VMA21 were found to be attached to the RNA-induced silencing complex constructed from miR-18b-5p and Ago2. Also, ZFPM2-AS1 could regulate the expression of VMA21. Therefore, ZFPM2-AS1 were confirmed to regulate VMA21 by competitively binding with miR-18b-5p. Finally, rescue assays confirmed that ZFPM2-AS1 could regulate LUAD cell proliferation via miR-18b-5p/VMA21 axis.