MiR-22 alleviates the proliferation and metastasis of melanoma by targeting FASN

Purpose: To determine the role of microRNA-22 (miR-22) in the development of malignant melanoma, and the underlying mechanism. Methods: Potential miRNAs binding fatty acid synthase (FASN) were predicted by bioinformatics analysis, out of which miR-22 was selected. Their binding relationship was confirmed using dual-luciferase reporter assay. MicroRNA-22 and FASN levels in 40 clinical samples of melanoma were determined, and the correlation of the expression between miR-22 and FASN was assessed by Pearson correlation test. To uncover the role of miR-22 in regulating cell phenotypes of malignant melanoma, M21 and A375 cells were transfected with miRNA-NC, miR-22 mimics or miR-22 mimics + FASN-OE (FASN-over expression), respectively. Proliferative and metastatic abilities in each group were determined using cell counting kit-8 (CCK-8), 5-Ethynyl-2’- deoxyuridine (EdU) and Transwell assay, respectively. Results: MiR-22 was the target gene binding the oncogene, FASN. Downregulated miR-22 and upregulated FASN were observed in melanoma tissues, showing a negative correlation between them. An overexpression of miR-22 significantly inhibited proliferative, migratory and invasive capacities in M21 and A375 cells (p < 0.05). Notably, overexpression of FASN abolished the inhibitory effects of miR-22 on proliferative and metastatic abilities in melanoma. Conclusion: The level of expression of miR-22 in the malignant melanoma samples is low. Overexpression of miR-22 inhibits the proliferative and metastatic abilities of melanoma by targeting FASN and negatively regulating its level. Thus, miR-22 may be a promising therapeutic target of melanoma

Mycoplasma genitalium Lipoproteins Induce Human Monocytic Cell Expression of Proinflammatory Cytokines and Apoptosis by Activating Nuclear Factor κB

This study was designed to investigate the molecular mechanisms responsible for the induction of proinflammatory cytokines gene expression and apoptosis in human monocytic cell line THP-1 stimulated by lipoproteins (LPs) prepared from Mycoplasma genitalium. Cultured cells were stimulated with M. genitalium LP to analyze the production of proinflammatory cytokines and expression of their mRNA by ELISA and RT-PCR, respectively. Cell apoptosis was also detected by Annexin V-FITC-propidium iodide (PI) staining and acridine orange (AO)-ethidium bromide (EB) staining. The DNA-binding activity of nuclear factor-κB (NF-κB) was assessed by electrophoretic mobility shift assay (EMSA). Results showed that LP stimulated THP-1 cells to produce tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in a dose-dependent manner. The mRNA levels were also upregulated in response to LP stimulation. LPs were also found to increase the DNA-binding activity of NF-κB, a possible mechanism for the induction of cytokine mRNA expression and the cell apoptosis. These effects were abrogated by PDTC, an inhibitor of NF-κB. Our results indicate that M. genitalium-derived LP may be an important etiological factor of certain diseases due to the ability of LP to produce proinflammatory cytokines and induction of apoptosis, which is probably mediated through the activation of NF-κB

Licarin-B Exhibits Activity Against the Toxoplasma gondii RH Strain by Damaging Mitochondria and Activating Autophagy

Toxoplasma gondii is an obligate intracellular pathogen that infects warm-blooded animals and humans. However, side effects limit toxoplasmosis treatment, and new drugs with high efficiency and low toxicity need to be developed. Natural products found in plants have become a useful source of drugs for toxoplasmosis. In this study, twenty natural compounds were screened for anti-T. gondii activity by Giemsa staining or real-time fluorescence quantitative polymerase chain reaction (qPCR) in vitro. Among these, licarin-B from nutmeg exhibited excellent anti-T. gondii activity, inhibiting T. gondii invasion and proliferation in a dose-dependent manner, with an EC50 of 14.05 ± 3.96 μg/mL. In the in vivo, licarin-B treatment significantly reduced the parasite burden in tissues compared to no treatment, protected the 90% infected mice from to death at 50 mg/kg.bw. Flow cytometry analysis suggested a significant reduction in T. gondii survival after licarin-B treatment. Ultrastructural changes in T. gondii were observed by transmission electron microscopy (TEM), as licarin-B induced mitochondrial swelling and formation of cytoplasmic vacuoles, an autophagosome-like double-membrane structure and extensive clefts around the T. gondii nucleus. Furthermore, MitoTracker Red CMXRos, MDC, and DAPI staining showed that licarin-B promoted mitochondrial damage, autophagosome formation, and nuclear disintegration, which were consistent with the TEM observations. Together, these findings indicate that licarin-B is a promising anti-T. gondii agent that potentially functions by damaging mitochondria and activating autophagy, leading to T. gondii death

Rabbit Hemorrhagic Disease Virus Non-structural Protein 6 Induces Apoptosis in Rabbit Kidney Cells

Rabbit hemorrhagic disease (RHD) is a highly contagious disease caused by rabbit hemorrhagic disease virus (RHDV). Previous research has shown that RHDV induces apoptosis in numerous cell types, although the molecular mechanisms underlying the apoptosis induced by RHDV are not well understood. One possible factor is non-structural protein 6 (NSP6), a 3C-like protease that plays an important role in processing viral polyprotein precursors into mature non-structural proteins. To fully establish a role for NSP6, the present study examined the effects of ectopic expression of the protein in rabbit (RK13) and human (HeLa and HepG2) cells. We found that NSP6 suppressed cell viability and promoted apoptosis in all three cell types in a dose-dependent manner. We also identified increased caspase-3, -8, and -9 activities in RK13 cell, and an increased Bax to Bcl2 mRNA ratio. Mechanistically, the ability of NSP6 to induce apoptosis was impaired by mutation of the catalytic His27 residue. Our study has shown that RHDV NSP6 can induce apoptosis in host cells and is likely an important contributor to RHDV-induced apoptosis and pathogenesis

SPI1-induced downregulation of FTO promotes GBM progression by regulating pri-miR-10a processing in an m6A-dependent manner

As one of the most common post-transcriptional modifications of mRNAs and noncoding RNAs, N6-methyladenosine (m6A) modification regulates almost every aspect of RNA metabolism. Evidence indicates that dysregulation of m6A modification and associated proteins contributes to glioblastoma (GBM) progression. However, the function of fat mass and obesity-associated protein (FTO), an m6A demethylase, has not been systematically and comprehensively explored in GBM. Here, we found that decreased FTO expression in clinical specimens correlated with higher glioma grades and poorer clinical outcomes. Functionally, FTO inhibited growth and invasion in GBM cells in vitro and in vivo. Mechanistically, FTO regulated the m6A modification of primary microRNA-10a (pri-miR-10a), which could be recognized by reader HNRNPA2B1, recruiting the microRNA microprocessor complex protein DGCR8 and mediating pri-miR-10a processing. Furthermore, the transcriptional activity of FTO was inhibited by the transcription factor SPI1, which could be specifically disrupted by the SPI1 inhibitor DB2313. Treatment with this inhibitor restored endogenous FTO expression and decreased GBM tumor burden, suggesting that FTO may serve as a novel prognostic indicator and therapeutic molecular target of GBM.publishedVersio

The dual role of glioma exosomal microRNAs: glioma eliminates tumor suppressor miR-1298-5p via exosomes to promote immunosuppressive effects of MDSCs

Clear evidence shows that tumors could secrete microRNAs (miRNAs) via exosomes to modulate the tumor microenvironment (TME). However, the mechanisms sorting specific miRNAs into exosomes are still unclear. In order to study the biological function and characterization of exosomal miRNAs, we performed whole-transcriptome sequencing in 59 patients’ whole-course cerebrospinal fluid (CSF) small extracellular vesicles (sEV) and matched glioma tissue samples. The results demonstrate that miRNAs could be divided into exosome-enriched miRNAs (ExomiRNAs) and intracellular-retained miRNAs (CLmiRNAs), and exosome-enriched miRNAs generally play a dual role. Among them, miR-1298-5p was enriched in CSF exosomes and suppressed glioma progression in vitro and vivo experiments. Interestingly, exosomal miR-1298-5p could promote the immunosuppressive effects of myeloid-derived suppressor cells (MDSCs) to facilitate glioma. Therefore, we found miR-1298-5p had different effects on glioma cells and MDSCs. Mechanically, downstream signaling pathway analyses showed that miR-1298-5p plays distinct roles in glioma cells and MDSCs via targeting SETD7 and MSH2, respectively. Moreover, reverse verification was performed on the intracellular-retained miRNA miR-9-5p. Thus, we confirmed that tumor-suppressive miRNAs in glioma cells could be eliminated through exosomes and target tumor-associated immune cells to induce tumor-promoting phenotypes. Glioma could get double benefit from it. These findings uncover the mechanisms that glioma selectively sorts miRNAs into exosomes and modulates tumor immunity.publishedVersio

Seasonality of the transmissibility of hand, foot and mouth disease: a modelling study in Xiamen City, China.

This study attempts to figure out the seasonality of the transmissibility of hand, foot and mouth disease (HFMD). A mathematical model was established to calculate the transmissibility based on the reported data for HFMD in Xiamen City, China from 2014 to 2018. The transmissibility was measured by effective reproduction number (Reff) in order to evaluate the seasonal characteristics of HFMD. A total of 43 659 HFMD cases were reported in Xiamen, for the period 2014 to 2018. The median of annual incidence was 221.87 per 100 000 persons (range: 167.98/100,000-283.34/100 000). The reported data had a great fitting effect with the model (R2 = 0.9212, P < 0.0001), it has been shown that there are two epidemic peaks of HFMD in Xiamen every year. Both incidence and effective reproduction number had seasonal characteristics. The peak of incidence, 1-2 months later than the effective reproduction number, occurred in Summer and Autumn, that is, June and October each year. Both the incidence and transmissibility of HFMD have obvious seasonal characteristics, and two annual epidemic peaks as well. The peak of incidence is 1-2 months later than Reff