First Description of the Generation of Human Schwann Cells Transfected With CRISPR Cas9 and a Model of Metformin Mitochondrial Metabolism in Metachromatic Leukodystrophy

Background: Metachromatic leukodystrophy (MLD) is a neurological lysosomal deposit disease that has an impact on public health despite its low incidence in the population. Existing treatments are expensive and inefficient. Few reports in the literature on pathophysiological events related to enzyme deficiency and subsequent accumulation of sulfatides; therefore, the use of metformin as an alternative treatment was evaluated in vitro to counteract the effects. Methodology: An experimental in vitro study that sought to determine the effect of the use of metformin on the accumulation of sulfates in glycolysis and mitochondrial function in an in vitro model of metachromatic leukodystrophy. Human Schwann cells (CSH) transfected with CRISPR Cas9 and without transfection were treated with different concentrations of sulfatides and metformin. Cell viability was evaluated by MTT and SYTOX Green; mitochondrial and glycolytic function by Seahorse XFe24, determination of reactive oxygen species (ROS) and cell death. Results: In the MTT trials, we found that treatment with different concentrations of sulfates did not affect cell viability. Transfected CSH showed higher cell death and ROS production when exposed to 100 µM sulfatides with a statistically significant difference (p <0.001), compared to nontransfected CSH cells. Sulfatides at concentrations of 10 to 100 µM affect mitochondrial bioenergetics as concentrations increase in transfected cells, in nontransfected cells they respond metabolically to exposure; Furthermore, transfected cells show a decrease in basal respiration and maximum respiration after being exposed to a concentration of 100 µM of sulphates; however, in double treatment of these cells with both sulfates and Metformin, respiration also decreases. Maximum and normal mitochondrial respiratory capacity. Conclusion: This research describes for the first time the generation of transfected CSH and the bioenergetic and mitochondrial effect of sulfates in Schwann cells, treatment with 500 µM of Metformin restores metabolic activity of these cells and decreases ROS production, as well as prevention of cell death.

Class I HDAC Inhibitor Rescues Synaptic Damage and Neuron Loss in APP-Transfected Cells and APP/Ps1 Mice through the GRIP1/AMPA Pathway

As a neurodegenerative disease, Alzheimer's disease (AD) seriously affects the health of older people. It is now known that changes in synapses occur first in the course of disease, perhaps even before the formation of Aβ plaques. Histone deacetylase (HDAC) can mediate the damage of Aβ oligomers to dendritic spines. Therefore, we examined the relationship between HDAC activity and synaptic defects by using an HDACI, BG45 in Human neuroblastoma SH-SY5Y cell line with stable overexpression of Swedish mutant APP (APPsw) and in APP/Ps1 transgenic mice during this study. The cells were treated with 15µM BG45 and the APP/Ps1 mice 30mg/kg BG45. We detected the level of synapse-related proteins, HDACs, tau phosphorylation and AMPA receptors by western bloting and immunohistochemistry. We also measured the expression of cytoskeletal proteins in the cell model. The mRNA level of GRIK2, SCN3B, SYNPR, Grm2, Grid2IP, GRIP1,GRIP2 were. to explore the effects of HDACi on regulating the synaptic proteins and AMPA receptors. Our studies demonstrated that the expression of HDAC1、HDAC2 and HDAC3 was increased, which was accompanied by the downregulation of the synapse-related proteins synaptophysin (SYP), postsynaptic dendritic protein (PSD-95) and spinophilin as early as 24 h after transfection with APPsw gene. BG45 upregulated the expression of synapse-related proteins and repaired cytoskeletal damage. In vivo, BG45 alleviated the apoptotic loss of hippocampal neurons, upregulated synapse-related proteins, reduced Aβ deposition and phosphorylation of tau and increased the level of the synapse-related genes GRIK2, SCN3B, SYNPR, Grm2, and Grid2IP. BG45 increased the expression of the AMPA receptor subunits GluA1, GluA2 and GluA3 on APPsw-transfected cells and increased GRIP1 and GRIP2 expression and AMPA receptor phosphorylation in vivo. These results suggest that HDACs are involved in the early process of synaptic defects of AD and that BG45 may rescue synaptic damage and loss of hippocampal neurons by specifically inhibiting HDAC1、HDAC2 and HDAC3, thereby modulating AMPA receptor transduction, increasing synapse-related gene expression and finally improving excitatory synapses. BG45 may be considered as a potential drug for the treatment of early AD for further study.

Autophagy Overactivity Regulate Terf1 and Terf2 in Positive and Negative-Telomerase Cancer Cell Lines

A recent suggestion for cancer therapy is targeting intracellular homeostatic signaling pathways like autophagy providing the balance between metabolism and cell cycling. Our study focused on investigating the relationship between autophagy activation by Beclin1 transfection and assessing Terf1 and Terf2 expression as shelterin proteins. The beclin1-containing plasmid was introduced to the U-2OS and Huh7 cell lines using Lipofectamine. The LC3-II as an intracellular autophagosomal marker was detected in transfected cells by flow cytometry. Also, the cells were treated with 3-methyladenine and metformin as autophagy inhibitors and inducers, respectively. Finally, the expression levels of Terf1 and Terf2 were analyzed by real-time PCR. Fluorescent images and flow cytometry results proved excellent GFP expression in the transfected cells. The results of real-time PCR demonstrated that autophagy induction by Beclin1 was increased Terf1 expression level in U-2OS cells up to 451%, while Huh7 cells suffered from the decreased expression of Terf1. Altogether, Terf2 expression was enhanced significantly in both cell lines after 48h treatment in comparison with 24h treatment. The obtained data provided that Beclin1-based activation of autophagy leads to overexpression of some protective shelterin proteins.

Mycoplasma genitalium Protein of Adhesion Promotes the Early Proliferation of Human Urothelial Cells by Interacting with RPL35

Mycoplasma genitalium is a newly recognized pathogen associated with sexually transmitted diseases (STDs). MgPa, the adhesion protein of Mycoplasma genitalium, is the main adhesin and the key factor for M. genitalium interacting with host cells. Currently, the long-term survival mechanism of M. genitalium in the host is not clear. In this study, a T7 phage-displayed human urothelial cell (SV-HUC-1) cDNA library was constructed, and the interaction of MgPa was screened from this library using the recombinant MgPa (rMgPa) as a target molecule. We verified that 60S ribosomal protein L35 (RPL35) can interact with MgPa using far-Western blot and co-localization analysis. According to the results of tandem mass tag (TMT) labeling and proteome quantitative analysis, there were altogether 407 differentially expressed proteins between the pcDNA3.1(+)/MgPa-transfected cells and non-transfected cells, of which there were 6 downregulated proteins and 401 upregulated proteins. The results of qRT-PCR demonstrated that interaction between rMgPa and RPL35 could promote the expressions of EIF2, SRP68, SERBP1, RPL35A, EGF, and TGF-β. 3-(4,5)-Dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide bromide (MTT) assays corroborated that the interaction between rMgPa and RPL35 could promote SV-HUC-1 cell proliferation. Therefore, our findings indicated that the interaction between rMgPa and RPL35 can enhance the expressions of transcription-initiation and translation-related proteins and thus promote cell proliferation. This study elucidates a new biological function of MgPa and can explain this new mechanism of M. genitalium in the host.

Characterization of a mutated KCNJ5 gene, G387R, in unilateral primary aldosteronism

Somatic mutation in the KCNJ5 gene is a common driver of autonomous aldosterone overproduction in aldosterone-producing adenomas (APA). KCNJ5 mutations contribute to a loss of potassium selectivity, and an inward Na+ current could be detected in cells transfected with mutated KCNJ5. Among 223 unilateral primary aldosteronism (uPA) individuals with a KCNJ5 mutation, we identified 6 adenomas with a KCNJ5 p.Gly387Arg (G387R) mutation, previously unreported in uPA patients. The six uPA patients harboring mutant KCNJ5-G387R were older, had a longer hypertensive history, and had milder elevated preoperative plasma aldosterone levels than those APA patients with more frequently detected KCNJ5 mutations. CYP11B2 immunohistochemical staining was only positive in three adenomas, while the other three had co-existing multiple aldosterone-producing micronodules. The bioinformatics analysis predicted that function of the KCNJ5-G387R mutant channel could be pathological. However, the electrophysiological experiment demonstrated that transfected G387R mutant cells did not have an aberrantly stimulated ion current, with lower CYP11B2 synthesis and aldosterone production, when compared to that of the more frequently detected mutant KCNJ5-L168R transfected cells. In conclusion, mutant KCNJ5-G387R is not a functional KCNJ5 mutation in unilateral PA. Compared with other KCNJ5 mutations, the observed mildly elevated aldosterone expression actually hindered the clinical identification of clinical unilateral PA. The KCNJ5-G387R mutation needs to be distinguished from functional KCNJ5 mutations during genomic analysis in APA evaluation because of its functional silence.

Selenium-Dependent Read Through of the Conserved 3’-Terminal UGA Stop Codon of HIV-1 nef

Objectives: The HIV-1 nef gene terminates in a 3’-UGA stop codon, which is highly conserved in the main group of HIV-1 subtypes, along with a downstream potential coding region that could extend the nef protein by 33 amino acids, if readthrough of the stop codon occurs. It has been proposed that antisense tethering interactions (ATIs) between a viral mRNA and a host selenoprotein mRNA are a potential viral strategy for the capture of a host selenocysteine insertion sequence (SECIS) element. This mRNA hijacking mechanism could enable the expression of virally encoded selenoprotein modules, through translation of in-frame UGA stop codons as selenocysteine (Sec). Here, our aim was to assess whether readthrough of the 3’-terminal UGA codon of nef occurs during translation of HIV-1 nef expression constructs in transfected cells, and whether selenium-based mechanisms might be involved. Material and Methods: To assess UGA codon readthrough, we used fluorescence microscopy image analysis and flow cytometry of HEK 293 cells transfected with full length HIV-1 nef gene expression constructs including the 3’-UGA stop codon and a predicted thioredoxin reductase 1 (TXNRD1) antisense region spanning the UGA codon, engineered with a downstream in-frame green fluorescent protein (GFP) reporter gene. These were designed so that GFP can only be expressed by translational recoding of the UGA codon, that is, if the UGA codon is translated as an amino acid or bypassed by ribosomal hopping. To assess readthrough efficiency, appropriate mutant control constructs were used for 100% and 0% readthrough. We used anti-TXNRD1 siRNA to assess the possible role of the proposed antisense interaction in this event, by knockdown of TXNRD1 mRNA levels. Results: UGA stop codon readthrough efficiency for the wild-type nef construct was estimated by flow cytometry to be about 19% (P < 0.0001). siRNA knockdown of TXNRD1 mRNA resulted in a 67% decrease in GFP expression in this system relative to control cells (P < 0.0001), presumably due to reduced availability of the components involved in selenocysteine incorporation for the stop codon readthrough (i.e. the TXNRD1 SECIS element). Addition of 20 nM sodium selenite to the media enhanced stop codon readthrough in the pNefATI1 plasmid construct by >100% (P < 0.0001), that is, more than doubled the amount of readthrough product, supporting the hypothesis that selenium is involved in the UGA readthrough mechanism. Conclusion: Our results show that readthrough of the 3’-terminal UGA codon of nef occurs during translation of HIV-1 nef expression constructs in transfected cells, that this is dependent on selenium concentration, and the presence of TXNRD1 mRNA, supporting the proposed antisense tethering interaction.

Identification of Novel Anthracycline Resistance Genes and Their Inhibitors

Differentially expressed genes have been previously identified by us in multidrug-resistant tumor cells mainly resistant to doxorubicin. In the present study, we exemplarily focused on some of these genes to investigate their causative relationship with drug resistance. HMOX1, NEIL2, and PRKCA were overexpressed by lentiviral-plasmid-based transfection of HEK293 cells. An in silico drug repurposing approach was applied using virtual screening and molecular docking of FDA-approved drugs to identify inhibitors of these new drug-resistant genes. Overexpression of the selected genes conferred resistance to doxorubicin and daunorubicin but not to vincristine, docetaxel, and cisplatin, indicating the involvement of these genes in resistance to anthracyclines but not to a broader MDR phenotype. Using virtual drug screening and molecular docking analyses, we identified FDA-approved compounds (conivaptan, bexarotene, and desloratadine) that were interacting with HMOX1 and PRKCA at even stronger binding affinities than 1-(adamantan-1-yl)-2-(1H-imidazol-1-yl)ethenone and ellagic acid as known inhibitors of HMOX1 and PRKCA, respectively. Conivaptan treatment increased doxorubicin sensitivity of both HMOX1- and PRKCA-transfected cell lines. Bexarotene treatment had a comparable doxorubicin-sensitizing effect in HMOX1-transfected cells and desloratadine in PRKCA-transfected cells. Novel drug resistance mechanisms independent of ABC transporters have been identified that contribute to anthracycline resistance in MDR cells.

VP8, the Major Tegument Protein of Bovine Herpesvirus-1, Is Partially Packaged during Early Tegument Formation in a VP22-Dependent Manner

Bovine herpesvirus-1 (BoHV-1) is a major cause of rhinotracheitis and vulvovaginitis in cattle. VP8, the major tegument protein of BoHV-1, is essential for viral replication in the host. VP8 is phosphorylated by the viral kinase US3, mediating its translocation to the cytoplasm. VP8 remains nuclear when not phosphorylated. Interestingly, VP8 has a significant presence in mature BoHV-1YmVP8, in which the VP8 phosphorylation sites are mutated. This suggests that VP8 might be packaged during primary envelopment of BoHV-1. This was investigated by mass spectrometry and Western blotting, which showed VP8, as well as VP22, to be constituents of the primary enveloped virions. VP8 and VP22 were shown to interact via co-immunoprecipitation experiments, in both BoHV-1-infected and VP8-transfected cells. VP8 and VP22 also co-localised with one another and with nuclear lamin-associated protein 2 in BoHV-1-infected cells, suggesting an interaction between VP8 and VP22 in the perinuclear region. In cells infected with VP22-deleted BoHV-1 (BoHV-1ΔUL49), VP8 was absent from the primary enveloped virions, implying that VP22 might be critical for the early packaging of VP8. In conclusion, a novel VP22-dependent mechanism for packaging of VP8 was identified, which may be responsible for a significant amount of VP8 in the viral particle.

Effect of miR-25 on Proliferation of Nasopharyngeal Carcinoma Cells through Wnt/β-Catenin Signaling Pathway

Objective. To investigate the biological role and potential mechanism of miR-25 in nasopharyngeal carcinoma. Methods. The expression of miR-25 in nasopharyngeal carcinoma cell lines was detected by qRT-PCR. The effect of inhibition of miR-25 expression on the proliferative activity of nasopharyngeal carcinoma cell line HONE-1 was examined by CCK-8 method. Flow cytometry was used to detect the effect of miR-25 expression inhibition on the apoptosis rate of nasopharyngeal carcinoma cell line HONE-1. The miRNA target gene prediction site TargetScan predicts the target protein action site of miR-124 and verifies whether miR-25 interacts with the target by luciferase activity assay, qPCR, and Western experiments. The miR-25 inhibitor and target egg gene expression plasmids were cotransfected into HONE-1 cells for rescue experiments to investigate whether miR-25 inhibits proliferation of nasopharyngeal carcinoma cells by target genes. At the same time, qRT-PCR was used to detect the mRNA expression levels of Wnt/β-catenin pathway key proteins TCF4, c-Myc, and Cyclin D1 in different transfected cells. Results. miR-25 expression was upregulated in nasopharyngeal carcinoma cell lines. Functional studies showed that inhibition of miR-25 expression significantly inhibited the proliferation of nasopharyngeal carcinoma cell line HONE-1 ( p < 0.05 ). Inhibition of miR-25 expression by flow cytometry significantly promoted apoptosis ( p < 0.05 ). Detection of dual luciferase activity indicated that DKK3 is a direct target site for miR-25. Western blots showed that inhibition of miR-25 significantly upregulated DKK3 mRNA and protein levels. Supplementation with DKK3 significantly attenuated the inhibitory effect of miR-25 on the proliferation of nasopharyngeal carcinoma cell line HONE-1 ( p < 0.05 ). qRT-PCR found that mRNA levels of TCF4, c-Myc, and Cyclin D1 were significantly upregulated in miR-25-transfected cells compared to control transfection. QRT PCR showed that the mRNA and protein levels of Tcf4, c-myc, and Cyclin D1 were significantly upregulated in miR-25 overexpression-transfected cells. Conclusion. Inhibition of miR-25 expression promotes DKK3 gene expression, and inactivation of Wnt/β-catenin signaling pathway inhibits proliferation and promotes apoptosis of nasopharyngeal carcinoma cells.

Taxifolin and Sorghum Ethanol Extract Protect against Hepatic Insulin Resistance via the miR-195/IRS1/PI3K/AKT and AMPK Signalling Pathways

This study aimed to evaluate the effects of taxifolin and sorghum ethanol extract on free fatty acid (FFA)-induced hepatic insulin resistance. FFA treatment decreased glucose uptake by 16.2% compared with that in the control, whereas taxifolin and sorghum ethanol extract increased the glucose uptake. Additionally, taxifolin and sorghum ethanol extract increased the expression of p-PI3K, p-IRS1, p-AKT, p-AMPK, and p-ACC in FFA-induced hepatocytes. Furthermore, FFA treatment increased the expression of miR-195. However, compared with the FFA treatment, treatment with taxifolin and sorghum ethanol extract decreased miR-195 expression in a dose-dependent manner. Taxifolin and sorghum ethanol extract enhanced p-IRS1, p-PI3K, p-AMPK, p-AKT, and p-ACC expression by suppressing miR-195 levels in miR-195 mimic- or inhibitor-transfected cells. These results indicate that taxifolin and sorghum ethanol extract attenuate insulin resistance by regulating miR-195 expression, which suggests that taxifolin and sorghum ethanol extract may be useful antidiabetic agents.