Major vault protein (MVP) gene polymorphisms and drug resistance in mesial temporal lobe epilepsy with hippocampal sclerosis

Human Vault RNAs: Exploring Their Potential Role in Cellular Metabolism

Non-coding RNAs have been described as crucial regulators of gene expression and guards of cellular homeostasis. Some recent papers focused on vault RNAs, one of the classes of non-coding RNA, and their role in cell proliferation, tumorigenesis, apoptosis, cancer response to therapy, and autophagy, which makes them potential therapy targets in oncology. In the human genome, four vault RNA paralogues can be distinguished. They are associated with vault complexes, considered the largest ribonucleoprotein complexes. The protein part of these complexes consists of a major vault protein (MVP) and two minor vault proteins (vPARP and TEP1). The name of the complex, as well as vault RNA, comes from the hollow barrel-shaped structure that resembles a vault. Their sequence and structure are highly evolutionarily conserved and show many similarities in comparison with different species, but vault RNAs have various roles. Vaults were discovered in 1986, and their functions remained unclear for many years. Although not much is known about their contribution to cell metabolism, it has become clear that vault RNAs are involved in various processes and pathways associated with cancer progression and modulating cell functioning in normal and pathological stages. In this review, we discuss known functions of human vault RNAs in the context of cellular metabolism, emphasizing processes related to cancer and cancer therapy efficacy.

Small but Powerful: The Human Vault RNAs as Multifaceted Modulators of Pro-Survival Characteristics and Tumorigenesis

Simple Summary

Small non-protein-coding RNAs have been recognized as valuable regulators of gene expression in all three domains of life. Particularly in multicellular organisms, ncRNAs-mediated gene expression control has evolved as a central principle of cellular homeostasis. Thus, it is not surprising that non-coding RNA misregulation has been linked to various diseases. Here, we review the contributions of the four human vault RNAs to cellular proliferation, apoptosis and cancer biology.

Abstract

The importance of non-coding RNAs for regulating gene expression has been uncovered in model systems spanning all three domains of life. More recently, their involvement in modulating signal transduction, cell proliferation, tumorigenesis and cancer progression has also made them promising tools and targets for oncotherapy. Recent studies revealed a class of highly conserved small ncRNAs, namely vault RNAs, as regulators of several cellular homeostasis mechanisms. The human genome encodes four vault RNA paralogs that share significant sequence and structural similarities, yet they seem to possess distinct roles in mammalian cells. The alteration of vault RNA expression levels has frequently been observed in cancer tissues, thus hinting at a putative role in orchestrating pro-survival characteristics. Over the last decade, significant advances have been achieved in clarifying the relationship between vault RNA and cellular mechanisms involved in cancer development. It became increasingly clear that vault RNAs are involved in controlling apoptosis, lysosome biogenesis and function, as well as autophagy in several malignant cell lines, most likely by modulating signaling pathways (e.g., the pro-survival MAPK cascade). In this review, we discuss the identified and known functions of the human vault RNAs in the context of cell proliferation, tumorigenesis and chemotherapy resistance.

Major vault protein attenuates cardiomyocyte injury in doxorubicin-induced cardiomyopathy through activating AKT

Background

Doxorubicin (DOX) has limited chemotherapy application for malignancies due to cardiotoxicity. The pathogenesis of DOX-induced cardiomyopathy (DiCM) is yet to be elucidated. Increasing studies proved that activation of AKT prevented cardiomyocyte apoptosis and cardiac dysfunction in response to DOX insult. Our previous studies indicated that major vault protein (MVP) deficiency was accompanied by suppressed phosphorylation of AKT in metabolic diseases. This study aimed to investigate the role and underlying mechanism of MVP on cardiomyocyte apoptosis in DiCM.

Methods

Mice were intraperitoneally injected with DOX 5 mg/kg, once a week for 5 weeks, the total cumulative dose was 25 mg/kg. Cardiomyocyte-specific MVP overexpression was achieved using an adeno-associated virus system under the cTnT promoter after the fourth DOX injection. Cardiac function was examined by echocardiography followed by euthanasia. Tissue and serum were collected for morphology analysis and biochemical examination.

Results

Herein, we found that MVP expression was upregulated in DOX-treated murine hearts. Cardiac-specific MVP overexpression alleviated DOX-induced cardiac dysfunction, oxidative stress and fibrosis. Mechanistically, MVP overexpression activated AKT signaling and decreased cardiomyocyte apoptosis in DiCM.

Conclusions

Based on these findings, we supposed that MVP was a potential therapeutic agent against DiCM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02517-9.

Multi-omic strategies applied to the study of pharmacoresistance in mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adults, and hippocampal sclerosis (HS) is a frequent histopathological feature in patients with MTLE. Pharmacoresistance is present in at least one-third of patients with MTLE with HS (MTLE+HS). Several hypotheses have been proposed to explain the mechanisms of pharmacoresistance in epilepsy, including the effect of genetic and molecular factors. In recent years, the increased knowledge generated by high-throughput omic technologies has significantly improved the power of molecular genetic studies to discover new mechanisms leading to disease and response to treatment. In this review, we present and discuss the contribution of different omic modalities to understand the basic mechanisms determining pharmacoresistance in patients with MTLE+HS. We provide an overview and a critical discussion of the findings, limitations, new approaches, and future directions of these studies to improve the understanding of pharmacoresistance in MTLE+HS. However, it is important to point out that, as with other complex traits, pharmacoresistance to anti-seizure medications is likely a multifactorial condition in which gene-gene and gene-environment interactions play an important role. Thus, studies using multidimensional approaches are more likely to unravel these intricate biological processes.

Major vault protein plays important roles in viral infection

Viral replication and related protein expression inside the host cells, and host antiviral immune responses can lead to the occurrence of diverse diseases. With the outbreak of viral infection, a large number of newly diagnosed and died patients infected with various viruses are still reported every year. Viral infection has already been one of the major global public health issues and lead to huge economic and social burdens. Studying of viral pathogenesis is a very important way to find methods for prevention, diagnosis, and cure of viral infection; more evidence has confirmed that major vault protein (MVP) is closely associated with viral infection and pathogenesis, and this review is intended to provide a broad relationship between viruses and MVP to stimulate the interest of related researchers.

Exosomes and their importance in metastasis, diagnosis, and therapy of colorectal cancer

Extracellular vesicles are known as actual intermediaries of intercellular communications, such as biological signals and cargo transfer between different cells. A variety of cells release the exosomes as nanovesicular bodies. Exosomes contain different compounds such as several types of nucleic acids and proteins. In this study, we focused on exosomes in colorectal cancer as good tools that can be involved in various cancer-related processes. Furthermore, we summarize the advantages and disadvantages of exosome extraction methods and review related studies on the role of exosomes in colorectal cancer. Finally, we focus on reports available on relations between mesenchymal stem cell-derived exosomes and colorectal cancer. Several cancer-related processes such as cancer progression, metastasis, and drug resistance of colorectal cancer are related to the cargoes of exosomes. A variety of molecules, especially proteins, microRNAs, and long noncoding RNAs, play important roles in these processes. The microenvironment features, such as hypoxia, also have very important effects on the properties of the origin cell-derived exosomes. On the other hand, exosomes derived from colorectal cancer cells also interfere with cancer chemoresistance. Furthermore, today it is known that exosomes and their contents can likely be very effective in noninvasive colorectal cancer diagnosis and therapy. Thus, exosomes, and especially their cargoes, play different key roles in various aspects of basic and clinical research related to both progression and therapy of colorectal cancer.

Inhibition of Hepatitis E Virus Spread by the Natural Compound Silvestrol

Every year, there are about 20 Mio hepatitis E virus (HEV) infections and 60,000 deaths that are associated with HEV worldwide. At the present, there exists no specific therapy for HEV. The natural compound silvestrol has a potent antiviral effect against the (-)-strand RNA-virus Ebola virus, and also against the (+)-strand RNA viruses Corona-, Picorna-, and Zika virus. The inhibitory effect on virus spread is due to an inhibition of the DEAD-box RNA helicase eIF4A, which is required to unwind structured 5'-untranslated regions (UTRs). This leads to an impaired translation of viral RNA. The HEV (+)-strand RNA genome contains a 5'-capped, short 5'-UTR. This study aims to analyze the impact of silvestrol on the HEV life cycle. Persistently infected A549 cells were instrumental. This study identifies silvestrol as a potent inhibitor of the release of HEV infectious viral particles. This goes along with a strongly reduced HEV capsid protein translation, retention of viral RNA inside the cytoplasm, and without major cytotoxic effects. Interestingly, in parallel silvestrol affects the activity of the antiviral major vault protein (MVP) by translocation from the cytoplasm to the perinuclear membrane. These data further characterize the complex antiviral activity of silvestrol and show silvestrol's broad spectrum of function, since HEV is a virus without complex secondary structures in its genome, but it is still affected.

Acetazolamide Suppresses Multi-Drug Resistance-Related Protein 1 and P-Glycoprotein Expression by Inhibiting Aquaporins Expression in a Mesial Temporal Epilepsy Rat Model

Background

Mesial temporal epilepsy (MTLE) is the most common type of focal epilepsy in adults, and is often drug-resistant. This study investigated the effects of aquaporins (AQP) inhibitor on multi-drug-resistant protein expression in an MTLE rat model.

Material/Methods

The MTLE rat model was established by injecting pilocarpine into rats. The MTLE rats were divided into an MTLE-6 h group, an MTLE-12 h group, and an MTLE-24 h group, together with a normal saline group (NS), to examine the AQP4 expression by using Western blot assay and immunohistochemistry assay. The other 18 MTLE model rats were used to observe the effects of the AQP4 inhibitor, acetazolamide, on the multi-drug-resistant protein 1 (MRP1) and P-glycoprotein (Pgp) by using Western blot and immunohistochemistry assays, respectively.

Results

AQP4 expression was enhanced in hippocampal tissues of MTLE model rats compared to NS rats (P<0.05). More positively stained AQP4 was discovered in hippocampal tissues of MTLE model rats. AQP4 inhibitor significantly decreased multi-drug-resistant protein MRP1 and Pgp expression in the AQP4 inhibitor Interfere group and the AQP4 inhibitor Therapy group compared to the TMLE model group (P<0.05).

Conclusions

The present findings confirm that the AQP4 inhibitor, acetazolamide, effectively inhibits the multi-drug-resistant protein, MRP1, and Pgp, in the MTLE rat model.

Genetic susceptibility in Juvenile Myoclonic Epilepsy: Systematic review of genetic association studies

BACKGROUND

Several genetic association investigations have been performed over the last three decades to identify variants underlying Juvenile Myoclonic Epilepsy (JME). Here, we evaluate the accumulating findings and provide an updated perspective of these studies.

METHODOLOGY

A systematic literature search was conducted using the PubMed, Embase, Scopus, Lilacs, epiGAD, Google Scholar and Sigle up to February 12, 2016. The quality of the included studies was assessed by a score and classified as low and high quality. Beyond outcome measures, information was extracted on the setting for each study, characteristics of population samples and polymorphisms.

RESULTS

Fifty studies met eligibility criteria and were used for data extraction. With a single exception, all studies used a candidate gene approach, providing data on 229 polymorphisms in or near 55 different genes. Of variants investigating in independent data sets, only rs2029461 SNP in GRM4, rs3743123 in CX36 and rs3918149 in BRD2 showed a significant association with JME in at least two different background populations. The lack of consistent associations might be due to variations in experimental design and/or limitations of the approach.

CONCLUSIONS

Thus, despite intense research evidence established, specific genetic variants in JME susceptibility remain inconclusive. We discussed several issues that may compromise the quality of the results, including methodological bias, endophenotype and potential involvement of epigenetic factors.

PROSPERO REGISTRATION NUMBER

CRD42016036063.

MVP-mediated exosomal sorting of miR-193a promotes colon cancer progression

Exosomes are emerging mediators of intercellular communication; whether the release of exosomes has an effect on the exosome donor cells in addition to the recipient cells has not been investigated to any extent. Here, we examine different exosomal miRNA expression profiles in primary mouse colon tumour, liver metastasis of colon cancer and naive colon tissues. In more advanced disease, higher levels of tumour suppressor miRNAs are encapsulated in the exosomes. miR-193a interacts with major vault protein (MVP). Knockout of MVP leads to miR-193a accumulation in the exosomal donor cells instead of exosomes, inhibiting tumour progression. Furthermore, miR-193a causes cell cycle G1 arrest and cell proliferation repression through targeting of Caprin1, which upregulates Ccnd2 and c-Myc. Human colon cancer patients with more advanced disease show higher levels of circulating exosomal miR-193a. In summary, our data demonstrate that MVP-mediated selective sorting of tumour suppressor miRNA into exosomes promotes tumour progression.

Exosomes are involved in the development of metastasis but how their composition is regulated is not well known. Here the authors propose that major vault protein-dependent loading of miR-193a into exosomes could be a general mechanism by which cancer cells get rid of oncosuppressor miRNAs.

[Effects of cyclooxygenase-2 selective inhibitor celecoxib on the expression of major vault protein in rats with status epilepticus]

OBJECTIVE

To study the effect of cyclooxygenase -2 selective inhibitor celecoxib on the expression of major vault protein ( MVP) in the brain of rats with status epilepticus and its possible roles in the treatment of refractory epilepsy.

METHODS

Sixty adult male Sprague-Dawley rats were randomly assigned to blank control (n=16), epilepsy model (n=22) and celecoxib treatment groups (n=22). After the status epilepticus was induced in rats by injecting lithium and pilocarpine, each group had 16 rats enrolled as subjects. Immunohistochemical method and Western blot method were used to detect the expression of MVP in the frontal cortex and hippocampus.

RESULTS

The expression of MVP was significantly higher in the epilepsy model group than in the control group (P<0.01). The expression of MVP in the celecoxib treatment group was significantly decreased compared with the epilepsy model group, but it was still higher than in the control group (P<0.01).

CONCLUSIONS

Celecoxib could decrease the expression of MVP in brain tissue of rats with status epilepticus, suggesting that it is promising for the treatment of intractable epilepsy.

Association of single nucleotide polymorphisms in the MVP gene with platinum resistance and survival in patients with epithelial ovarian cancer

The human major vault protein (MVP) has been linked to the development of multidrug resistance in cancer cells, and overexpression of MVP has been observed in ovarian cancer tissues. The aim of the present study was to investigate the association between single nucleotide polymorphisms (SNPs) in the MVP gene and the tumor response to platinum-based chemotherapy and survival of patients affected by epithelial ovarian cancer (EOC), in addition to confirm whether tetra-primer amplification-refractory mutation system (ARMS)-polymerase chain reaction (PCR) is an accurate genotyping method. For this purpose, two polymorphisms in the MVP gene, namely reference SNP (rs)1057451 and rs4788186, were selected from the data obtained by the International haplotype map (HapMap) Project regarding Chinese Han population, and were evaluated by tetra-primer ARMS-PCR. Upon validation by DNA sequencing, the association of these polymorphisms with platinum resistance, progression-free survival (PFS) and overall survival (OS) in patients with EOC was assessed. The results of tetra-primer ARMS-PCR were in agreement with those derived from DNA sequencing. No significant differences were observed between platinum-sensitive and platinum-resistant cohorts in terms of allele and genotype distribution of these two polymorphisms in the MVP gene, which were not associated with PFS or OS. However, a trend toward prolonged PFS was observed in patients carrying the heterozygous AG allele at the rs4788186 locus. These results suggest that rs1057451 and rs4788186 variants in the MVP gene are not associated with favorable therapeutic response to platinum or longer survival in Chinese Han patients affected by EOC. In addition, the data of the present study confirm that tetra-primer ARMS-PCR is a trustworthy and economical genotyping method.

Association between single-nucleotide polymorphisms in DNA double-strand break repair genes and prostate cancer aggressiveness in the Spanish population

BACKGROUND

Novel predictors of prognosis and treatment response for prostate cancer (PCa) are required to better individualize treatment. Single-nucleotide polymorphisms (SNPs) in four genes directly (XRCC5 (X-ray repair complementing defective repair in Chinese hamster cells 5) and XRCC6 (X-ray repair complementing defective repair in Chinese hamster cells 6)) or indirectly (PARP1 and major vault protein (MVP)) involved in non-homologous end joining were examined in 494 Spanish PCa patients.

METHODS

A total of 22 SNPs were genotyped in a Biotrove OpenArray NT Cycler. Clinical tumor stage, diagnostic PSA serum levels and Gleason score at diagnosis were obtained for all participants. Genotypic and allelic frequencies were determined using the web-based environment SNPator.

RESULTS

(XRCC6) rs2267437 appeared as a risk factor for developing more aggressive PCa tumors. Those patients carrying the GG genotype were at higher risk of developing bigger tumors (odds ratio (OR)=2.04, 95% confidence interval (CI) 1.26-3.29, P=0.004), present higher diagnostic PSA levels (OR=2.12, 95% CI 1.19-3.78, P=0.011), higher Gleason score (OR=1.65, 95% CI 1.01-2.68, P=0.044) and D'Amico higher risk tumors (OR=2.38, 95% CI 1.24-4.58, P=0.009) than those patients carrying the CC/CG genotypes. Those patients carrying the (MVP) rs3815824 TT genotype were at higher risk of presenting higher diagnostic PSA levels (OR=4.74, 95% CI 1.40-16.07, P=0.013) than those patients carrying the CC genotype. When both SNPs were analyzed in combination, those patients carrying the risk genotypes were at higher risk of developing D'Amico higher risk tumors (OR=3.33, 95% CI 1.56-7.17, P=0.002).

CONCLUSIONS

We believe that for the first time, genetic variants at XRCC6 and MVP genes are associated with risk of more aggressive disease, and would be taken into account when assessing the malignancy of PCa.

Genetic association analysis of ATP binding cassette protein family reveals a novel association of ABCB1 genetic variants with epilepsy risk, but not with drug-resistance

Epilepsy constitutes a heterogeneous group of disorders that is characterized by recurrent unprovoked seizures due to widely different etiologies. Multidrug resistance remains a major issue in clinical epileptology, where one third of patients with epilepsy continue to have seizures. Role of efflux transporters in multidrug resistant epilepsy has been attributed to drug-resistant epilepsy although, with discrepant observation in genetic studies. These discrepancies could be attributed to variety of factors such as variable definition of the anti-epileptic drug (AED)-resistance, variable epilepsy phenotypes and ethnicities among the studies. In the present study we inquired the role of multidrug transporters ABCB1 and ABCG2 variants in determining AED-resistance and susceptibility to epilepsy in three well-characterized cohorts comprising of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) (prototype for AED-resistant epilepsy); juvenile myoclonic epilepsy (JME) (prototype for AED-responsive epilepsy); and healthy non-epileptic controls, in 738 subjects of Malayalam speaking south Indian ancestry. ABCB1 and ABCG2 variants were not found to be associated with drug resistance when AED-resistant and AED-responsive cohorts were compared. However, a significant association was observed between ABCB1 (C3435T) rs1045642 and risk of having epilepsy (MTLE-HS and JME pooled cohort; genotypic p-value = 0.0002; allelic p-value = 0.004). This association was seen persistent with MTLE-HS (genotypic p-value = 0.0008; allelic p-value = 0.004) and also with JME (genotypic p-value = 0.01; allelic p-value = 0.05) cohort individually. In-silico functional prediction indicated that ABCB1 rs1045642 has a deleterious impact on protein coding function and in splicing regulation. We conclude that the ABCB1 and ABCG2 variants do not confer to AED-resistance in the study population. However, ABCB1 rs1045642 increases vulnerability to epilepsy with greater tendency for MTLE-HS in south Indian ancestry from Kerala.