Hypoxic in vitro culture reduces histone lactylation and impairs pre-implantation embryonic development in mice

BACKGROUND

Dynamic changes of histone posttranslational modifications are important contexts of epigenetic reprograming after fertilization in pre-implantation embryos. Recently, lactylation has been reported as a novel epigenetic modification that regulates various cellular processes, but its role during early embryogenesis has not been elucidated.

RESULTS

We examined nuclear accumulation of H3K23la, H3K18la and pan histone lactylation in mouse oocytes and pre-implantation embryos by immunofluorescence with specific antibodies. All of the three modifications were abundant in GV stage oocytes, and both H3K23la and pan histone lactylation could be detected on the condensed chromosomes of the MII oocytes, while H3K18la were not detected. After fertilization, the nuclear staining of H3K23la, H3K18la and pan histone lactylation was faint in zygotes but homogeneously stained both of the parental pronuclei. The signal remained weak in the early cleavage stage embryos and increased remarkably in the blastocyst stage embryos. Comparison of the embryos cultured in four different conditions with varying concentrations of oxygen found that H3K23la, H3K18la and pan histone lactylation showed similar and comparable staining pattern in embryos cultured in atmospheric oxygen concentration (20% O₂), gradient oxygen concentration (5% O₂ to 2% O₂) and embryos obtained from in vivo, but the modifications were greatly reduced in embryos cultured in hypoxic condition (2% O₂). In contrast, nuclear accumulation of H3K18ac or H3K23ac was not significantly affected under hypoxic condition. Moreover, the developmental rate of in vitro cultured embryo was significantly reduced by low oxygen concentration and small molecule inhibition of LDHA activity led to decreased lactate production, as well as reduced histone lactylation and compromised developmental rate.

CONCLUSIONS

We provided for the first time the dynamic landscape of H3K23la, H3K18la and pan histone lactylation in oocytes and pre-implantation embryos in mice. Our data suggested that histone lactylation is subjected to oxygen concentration in the culture environment and hypoxic in vitro culture reduces histone lactylation, which in turn compromises developmental potential of pre-implantation embryos in mice.

Distinct role of histone chaperone Asf1a and Asf1b during fertilization and pre-implantation embryonic development in mice

Background

Asf1 is a well-conserved histone chaperone that regulates multiple cellular processes in different species. Two paralogous genes, Asf1a and Asf1b exist in mammals, but their role during fertilization and early embryogenesis remains to be investigated further.

Methods

We analyzed the dynamics of histone chaperone Asf1a and Asf1b in oocytes and pre-implantation embryos in mice by immunofluorescence and real-time quantitative PCR, and further investigated the role of Asf1a and Asf1b during fertilization and pre-implantation development by specific Morpholino oligos-mediated knock down approach.

Results

Immunofluorescence with specific antibodies revealed that both Asf1a and Asf1b were deposited in the nuclei of fully grown oocytes, accumulated abundantly in zygote and 2-cell embryonic nuclei, but turned low at 4-cell stage embryos. In contrast to the weak but definite nuclear deposition of Asf1a, Asf1b disappeared from embryonic nuclei at morula and blastocyst stages. The knockdown of Asf1a and Asf1b by specific Morpholino oligos revealed that Asf1a but not Asf1b was required for the histone H3.3 assembly in paternal pronucleus. However, knockdown of either Asf1a or Asf1b expression decreased developmental potential of pre-implantation embryos. Furthermore, while Asf1a KD severely reduced H3K56 acetylation level and the expression of Oct4 in blastocyst stage embryos, Asf1b KD almost eliminated nuclear accumulation of proliferating cell marker-PCNA in morula stage embryos. These results suggested that histone chaperone Asf1a and Asf1b play distinct roles during fertilization and pre-implantation development in mice.

Conclusions

Our data suggested that both Asf1a and Asf1b are required for pre-implantation embryonic development. Asf1a regulates H3K56ac levels and Oct4 expression, while Asf1b safeguards pre-implantation embryo development by regulating cell proliferation. We also showed that Asf1a, but not Asf1b, was necessary for the assembly of histone H3.3 in paternal pronuclei after fertilization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13072-021-00430-7.

Down-regulation of MYH10 driven by chromosome 17p13.1 deletion promotes hepatocellular carcinoma metastasis through activation of the EGFR pathway

Somatic copy number alterations (CNAs) are a genomic hallmark of cancers. Among them, the chromosome 17p13.1 deletions are recurrent in hepatocellular carcinoma (HCC). Here, utilizing an integrative omics analysis, we screened out a novel tumour suppressor gene within 17p13.1, myosin heavy chain 10 (MYH10). We observed frequent deletions (~38%) and significant down‐regulation of MYH10 in primary HCC tissues. Deletion or decreased expression of MYH10 was a potential indicator of poor outcomes in HCC patients. Knockdown of MYH10 significantly promotes HCC cell migration and invasion in vitro, and overexpression of MYH10 exhibits opposite effects. Further, inhibition of MYH10 markedly potentiates HCC metastasis in vivo. We preliminarily elucidated the mechanism by which loss of MYH10 promotes HCC metastasis by facilitating EGFR pathway activation. In conclusion, our study suggests that MYH10, a candidate target gene for 17p13 deletion, acts as a tumour suppressor and may serve as a potential prognostic indicator for HCC patients.

Association of exposure to deoxynivalenol with DNA methylation in white blood cells in children in China

Deoxynivalenol (DON) is a mycotoxin that commonly contaminates cereals worldwide. Dietary exposure to DON is a subject of great public health concern, but studies on the health effects of chronic exposure to DON are not available. In this study, we investigated the connection between DNA methylation levels and DON exposure in children. The DNA methylation status of white blood cells from 32 children aged 2~15 years old in Henan, China, was profiled. A total of 378 differentially methylated CpGs were identified between the high and low DON exposure groups, and 8 KEGG pathways were found to be significantly enriched among the differentially methylated genes. In addition, the quantitative methylation of EIF2AK4, EMID2 and GNASAS was analysed using the Sequenom MassARRAY platform. The results showed that the methylation level of EIF2AK4 was significantly different between the two groups, and the methylation levels were associated with exposure to DON. Conclusively, our study found that chronic exposure to DON during childhood could affect DNA methylation levels.

The interactions between MRI-detected osteophytes and bone marrow lesions or effusion-synovitis on knee symptom progression: an exploratory study

OBJECTIVES

To investigate the longitudinal association between MRI-detected osteophyte scores and progression of knee symptoms, and whether the association was modified in the presence of bone marrow lesions (BMLs) or effusion-synovitis.

METHODS

Data from Vitamin D Effects on Osteoarthritis (VIDEO) study, a randomized, double-blinded and placebo-controlled clinical trial in symptomatic knee osteoarthritis (OA) patients, were analyzed as an exploratory study. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to assess knee symptoms. Osteophytes, BMLs and effusion-synovitis were measured using MRI.

RESULTS

334 participants with MRI information and WOMAC score (baseline and follow-up) were included in the analyses, with 24.3% of them having knee pain increased 2 years later. Statistically significant interactions were found between MRI-detected osteophytes and BMLs or effusion-synovitis on increased knee symptoms. In participants with BMLs, higher baseline scores of MRI-detected osteophytes in most compartments were significantly associated with increased total knee pain, weight-bearing pain, stiffness, and physical dysfunction, after adjustment for age, sex, body mass index, intervention and effusion-synovitis. In participants with effusion-synovitis, higher baseline scores of MRI-detected osteophytes in almost all the compartments were significantly associated with increased total knee pain, weight-bearing pain, stiffness, and physical dysfunction, after adjustment for age, sex, body mass index, intervention and BMLs. In contrast, MRI-detected osteophyte scores were generally not associated with knee symptom progression in participants without baseline BMLs or effusion-synovitis.

CONCLUSIONS

MRI-detected OPs are associated with increased total knee pain, weight-bearing knee pain, stiffness and physical dysfunction in participants presenting BMLs or effusion-synovitis, but not in participants lacking BMLs or effusion-synovitis. This suggests they could interact with bone or synovial abnormalities to induce symptoms in knee OA.

Genome-wide association study of COVID-19 severity among the Chinese population

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes a broad clinical spectrum of coronavirus disease 2019 (COVID-19). The development of COVID-19 may be the result of a complex interaction between the microbial, environmental, and host genetic components. To reveal genetic determinants of susceptibility to COVID-19 severity in the Chinese population, we performed a genome-wide association study on 885 severe or critical COVID-19 patients (cases) and 546 mild or moderate patients (controls) from two hospitals, Huoshenshan and Union hospitals at Wuhan city in China. We identified two loci on chromosome 11q23.3 and 11q14.2, which are significantly associated with the COVID-19 severity in the meta-analyses of the two cohorts (index rs1712779: odds ratio [OR] = 0.49; 95% confidence interval [CI], 0.38-0.63 for T allele; P = 1.38 × 10^-8; and index rs10831496: OR = 1.66; 95% CI, 1.38-1.98 for A allele; P = 4.04 × 10^-8, respectively). The results for rs1712779 were validated in other two small COVID-19 cohorts in the Asian populations (P = 0.029 and 0.031, respectively). Furthermore, we identified significant eQTL associations for REXO2, C11orf71, NNMT, and CADM1 at 11q23.3, and CTSC at 11q14.2, respectively. In conclusion, our findings highlight two loci at 11q23.3 and 11q14.2 conferring susceptibility to the severity of COVID-19, which might provide novel insights into the pathogenesis and clinical treatment of this disease.

Genomic gain of RRS1 promotes hepatocellular carcinoma through reducing the RPL11-MDM2-p53 signaling

Hepatocellular carcinomas (HCCs) are characterized by frequent somatic genomic copy number alterations (CNAs), with most of them biologically unexplored. Here, we performed integrative analyses combining CNAs with the transcriptomic data to reveal the cis- and trans-effects of CNAs in HCC. We identified recurrent genomic gains of chromosome 8q, which exhibit strong trans-effects and are broadly associated with ribosome biogenesis activity. Furthermore, 8q gain-driven overexpression of ribosome biogenesis regulator (RRS1) promotes growth of HCC cells in vitro and in vivo. Mechanistically, RRS1 attenuates ribosomal stress through retaining RPL11 in the nucleolus, which, in turn, potentiates MDM2-mediated ubiquitination and degradation of p53. Clinically, higher RRS1 expression levels predict poor clinical outcomes for patients with HCC, especially in those with intact p53 Our findings established that the chromosome 8q oncogene RRS1 promotes HCC development through attenuating the RPL11-MDM2-p53 pathway and provided new potential targets for treatment of this malignancy.

Identification of Cancer Cell Stemness-Associated Long Noncoding RNAs for Predicting Prognosis of Patients with Hepatocellular Carcinoma

Long noncoding RNAs (lncRNAs) are emerging as crucial contributors to the development of hepatocellular carcinoma (HCC) and are involved in the stemness regulation of liver cancer stem cells (LCSCs). However, cancer cell stemness-associated lncRNAs and their relevance in prediction of clinical prognosis remain largely unexplored. In this study, through the transcriptome-wide screen, we identified a total of 136 LCSC-associated lncRNAs. We evaluated the prognostic value of these lncRNAs and optimally established an 11-lncRNA (including AC008622.2, AC015908.3, AC020915.2, AC025176.1, AC026356.2, AC099850.3, CYTOR, DDX11-AS1, HTR2A-AS1, LINC02870, and SNHG3) prognostic risk model. Multivariate analysis revealed that the risk score is an independent prognostic predictor for HCC patients, which outperforms the traditional clinical pathological factors. Gene set enrichment analysis suggested that the high-risk score reflects the alteration of pathways involved in cell cycle, oxidative phosphorylation, and metabolism. Furthermore, functional studies on SNHG12, the leading candidate of the risk lncRNAs, revealed that knockdown of SNHG12 reduces the abilities of HCC cells stemness, proliferation, migration, and invasion. In summary, we constructed a prognostic risk model based on 11 LCSC-associated lncRNAs, which might be a promising prognostic predictor for HCC patients and highlight the involvement of lncRNAs in LCSC-associated treatment strategy in clinical practice.

Characterization of DNA Methylation and Screening of Epigenetic Markers in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine and metabolic disorder in women, which is characterized by androgen excess, ovulation dysfunction, and polycystic ovary. Although the etiology of PCOS is largely unknown, many studies suggest that aberrant DNA methylation is an important contributing factor for its pathological changes. In this study, we investigated DNA methylation characteristics and their impact on gene expression in granulosa cells obtained from PCOS patients. Transcriptome analysis found that differentially expressed genes were mainly enriched in pathways of insulin resistance, fat cell differentiation, and steroid metabolism in PCOS. Overall DNA methylation level in granulosa cells was reduced in PCOS, and the first introns were found to be the major genomic regions that were hypomethylated in PCOS. Integrated analysis of transcriptome, DNA methylation, and miRNAs in ovarian granulosa cells revealed a DNA methylation and miRNA coregulated network and identified key candidate genes for pathogenesis of PCOS, including BMP4, ETS1, and IRS1. Our study shed more light on epigenetic mechanism of PCOS and provided valuable reference for its diagnosis and treatment.

Metabolic syndrome cannot mask the changes of faecal microbiota compositions caused by primary hepatocellular carcinoma

Both hepatocellular carcinoma (HCC) and metabolic syndrome are closely associated with the composition of the gut microbiota (GM). Although it has been proposed that elements of the GM can be used as biomarkers for the early diagnosis of HCC, whether metabolic syndrome results in a misrepresentation of the results of the early diagnosis of HCC using GM remains unclear. We compared the differences in the faecal microbiota of 10 patients with primary HCC, six patients with type 2 diabetes mellitus (T2DM), seven patients with arterial hypertension, six patients with both HCC and T2DM, and 10 patients with both HCC and arterial hypertension, as well as 10 healthy subjects, using high-throughput sequencing of 16S rRNA gene amplicons. Our results revealed a significant difference in the GM between subjects with and without HCC. The 49 bacterial genera out of the 494 detected genera were significantly different between the groups. These results show that changes in the GM can be used to distinguish between subjects with and without HCC, and can resist interference of T2DM and arterial hypertension with the GM. The results of the present study provide an important basis for the clinical auxiliary diagnosis of HCC by detecting the GM.

Unusual Near-Horizon Cosmic-Ray-like Events Observed by ANITA-IV

ANITA's fourth long-duration balloon flight in 2016 detected 29 cosmic-ray (CR)-like events on a background of 0.37_{-0.17}^{+0.27} anthropogenic events. CRs are mainly seen in reflection off the Antarctic ice sheets, creating a phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous noninverted polarity, a p=5.3×10^{-4} chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply upcoming anomalous events similar to the two such events seen in prior flights.

Effect of miR-133 on apoptosis of trophoblasts in human placenta tissues via Rho/ROCK signaling pathway

OBJECTIVE

The aim of this study was to explore the role of micro ribonucleic acid (miR)-133 in the apoptosis of human placental trophoblasts through the Ras homolog gene family (Rho)/Rho-associated coiled-coil forming protein kinase (ROCK) signaling pathway.

PATIENTS AND METHODS

The plasma samples were collected from 30 patients with pre-eclampsia (PE) undergoing treatment and 30 healthy subjects (control group) who received physical examination in our hospital. The Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was utilized to measure the expression of miR-133 in PE patients and healthy people. Meanwhile, blood pressure, urine protein content, liver function, and kidney function were detected in patients of both groups as well. Subsequently, the placental trophoblasts were extracted and transfected with inhibitors and miRNA mimics to suppress and overexpress miR-133, respectively. The transfection efficiency was determined by RT-PCR. The levels of interleukin-6 (IL-6), IL-1, and tumor necrosis factor-alpha (TNF-α) were measured in both groups. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay was performed to determine the apoptosis of trophoblasts. Next, the RT-PCR and Western blotting were carried out to detect the expressions of the Rho/ROCK pathway. Furthermore, the influence of miR-133 on the apoptosis of trophoblasts in human placenta tissues through Rho/ROCK was comprehensively observed.

RESULTS

In vivo experiments demonstrated that the urinary protein content, miR-133 level, systolic blood pressure, diastolic blood pressure, and liver function and renal function indexes were significantly elevated in pre-eclampsia (PE) patients in comparison with normal subjects (p<0.05). After transfection of mimics and inhibitors, the expression of miR-133 was remarkably up- and down-regulated, respectively. The content of the inflammatory factors in miR-133 mimics group was overtly higher than the other two groups. The TUNEL staining results showed that the number of apoptotic cells significantly increased and decreased in the miR-133 mimics group and miR-133 inhibitors group, respectively. Subsequent experiments indicated that the expressions of apoptosis gene Caspase3, pathway gene, and protein ROCKI were notably up-regulated in miR-133 mimics group. However, they were evidently down-regulated in miR-133 inhibitors group than in the control group. In addition, a consistent trend was observed in the protein expression level.

CONCLUSIONS

MiR-133 participates in the development and progression of PE through the Rho/ROCK signaling pathway, which may affect the apoptosis of trophoblasts in the placenta tissues.

[A long-term follow-up study on the occurrence of heterotopic ossification after artificial cervical disc replacement with Discover disc]

Objective: To analyze the incidence of heterotopic ossification after artificial cervical disc replacement with Discover disc, and to explore the effect of heterotopic ossification on postoperative radiological and clinical efficacy. Methods: From January 2010 to January 2015, 45 patients with cervical spondylosis underwent single-level artificial cervical disc replacement in Shanghai Changzheng Hospital, including 29 cases of cervical spondylotic myelopathy, 11 cases of cervical spondylotic radiculopathy and 5 cases of mixed cervical spondylosis. At the last follow-up, Mehren grading method was used for classification of heterotopic ossification, among which, grade 0-Ⅱ was defined as low grade ossification group, and 26 patients (16 male, 10 female) were enrolled in this group; grade Ⅲ-Ⅳ was defined as high grade ossification group, and 19 patients (12 males, 7 females) were included in this group. C(2-7) Cobb angle, cervical total range of motion and range of motion at index level were used to evaluate the radiological outcomes of the two groups. Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) score and visual analogue scale (VAS) were used to evaluate the clinical outcomes of the two groups. The adjacent segment intervertebral disc height and range of motion were used to evaluate the effects of heterotopic ossification on adjacent segment. Results: All patients were followed up regularly for (98±18) months. There were no statistical differences between the two groups regarding to demographic data (all P>0.05). There was no significant differences in C(2-7) Cobb angle and total range of motion between the two groups at the last follow-up (all P>0.05), but range of motion at index level in the group with low grades was significantly higher than that in the group with high grades (7.8°±6.2° vs 2.6°±1.2°, t=3.60, P<0.05). There was no significant differences in JOA score, recovery rate and NDI score between the two groups (all P>0.05). There was no significant differences in the adjacent segment intervertebral disc height before operation and at the last follow-up (both P>0.05). There was no significant differences in range of motion at adjacent segment before operation (P>0.05), while range of motion at adjacent segment in the group with low grades was significantly lower than that in the group with high grades (9.5°±1.1° vs 10.6°±1.8° and 9.4°±1.4° vs 10.5°±1.7°, repectively, t=2.54, 2.31, both P<0.05). Conclusions: Heterotopic ossification does not affect the clinical outcomes, cervical curvature and cervical total range of motion after artificial cervical disc replacement with Discover disc. However, the higher grade of heterotopic ossification, the lower range of motion at index level and the higher range of motion at adjacent segment.

Circ-ZNF609 promotes carcinogenesis of gastric cancer cells by inhibiting miRNA-145-5p expression

OBJECTIVE

To elucidate the expression pattern and biological function of circular RNA ZNF609 (circ-ZNF609) in gastric cancer (GC).

PATIENTS AND METHODS

Circ-ZNF609 expression in GC tissues and adjacent normal tissues (ANT) was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The regulatory effect of circ-ZNF609 on growth and metastasis of GC cells was evaluated through the Cell Counting Kit-8 (CCK-8), colony formation and transwell invasion assay, respectively. GC cell apoptosis influenced by circ-ZNF609 was examined by flow cytometry. The binding between circ-ZNF609 and miRNA-145-5p was verified by the Dual-Luciferase reporter gene assay. Finally, a series of rescue experiments were conducted to explore the mechanism of the circ-ZNF609/miRNA-145-5p axis in regulating GC progression.

RESULTS

QRT-PCR data revealed a higher level of circ-ZNF609 in GC tissues relative to ANT. Identically, circ-ZNF609 was highly expressed in GC cell lines relative to controls. The knockdown of circ-ZNF609 in BGC823 and MGC803 cells suppressed proliferative and invasive abilities. MiRNA-145-5p was predicted to be the target gene of circ-ZNF609 by bioinformatics, and further verified by the Dual-Luciferase reporter gene assay. Rescue experiments showed that miRNA-145-5p knockdown partially reversed the regulatory effect of circ-ZNF609 on growth and metastasis of GC cells.

CONCLUSIONS

Circ-ZNF609 promotes proliferative and invasive abilities of gastric cancer cells by inhibiting miRNA-145-5p expression as a ceRNA, thus accelerating gastric cancer progression.

Analysis of the Epigenetic Signature of Cell Reprogramming by Computational DNA Methylation Profiles

Background:

DNA methylation plays an important role in the reprogramming process. Understanding the underlying molecular mechanism of reprogramming is crucial for answering fundamental questions regarding the transition of cell identity.

Methods:

In this study, based on the genome-wide DNA methylation data from different cell lines, comparative methylation profiles were proposed to identify the epigenetic signature of cell reprogramming.

Results:

The density profile of CpG methylation showed that pluripotent cells are more polarized than Human Dermal Fibroblasts (HDF) cells. The heterogeneity of iPS has a greater deviation in the DNA hypermethylation pattern. The result of regional distribution showed that the differential CpG sites between pluripotent cells and HDFs tend to accumulate in the gene body and CpG shelf regions, whereas the internal differential methylation CpG sites (DMCs) of three types of pluripotent cells tend to accumulate in the TSS1500 region. Furthermore, a series of endogenous markers of cell reprogramming were identified based on the integrative analysis, including focal adhesion, pluripotency maintenance and transcription regulation. The calcium signaling pathway was detected as one of the signatures between NT cells and iPS cells. Finally, the regional bias of DNA methylation for key pluripotency factors was discussed. Our studies provide new insight into the barrier identification of cell reprogramming.

Conclusion:

Our studies analyzed some epigenetic markers and barriers of nuclear reprogramming, hoping to provide new insight into understanding the underlying molecular mechanism of reprogramming.

MicroRNA-374b inhibits migration and invasion of glioma cells by targeting EGFR

OBJECTIVE

To investigate the expression level of microRNA-374b in glioma tissues and its influence on the invasive ability of glioma cells. Meanwhile, the regulatory mechanism of microRNA-374b in glioma was also explored.

PATIENTS AND METHODS

The expression level of microRNA-374b in 32 glioma tissues and para-cancerous tissues were detected by quantitative Real-time polymerase chain reaction (qRT-PCR). The relationship between microRNA-374b expression and clinical indicators of glioma was analyzed. Meanwhile, the expression of microRNA-374b in glioma cells was verified by qRT-PCR as well. Subsequently, microRNA-374b over-expression model was constructed in glioma cell lines, including U251 and U87. Next, the effect of microRNA-374b on cellular biological functions was analyzed using cell counting kit-8 (CCK-8) assay, Wound healing test and transwell invasion assay, respectively. Finally, the relationship between miRNA and epidermal growth factor receptor (EGFR) was explored.

RESULTS

QRT-PCR results showed that the expression level of microRNA-374b in glioma was significantly lower than that of adjacent tissues, and the difference was statistically significant. Compared with patients with higher expression of microRNA-374b, the occurrence rate of lymph node or distant metastasis was significantly higher in those with lower microRNA-374b expression. In addition, compared with NC group, the proliferation, invasion and migration abilities of cells in microRNA-374b mimics group was significantly decreased. Subsequently, results demonstrated that the expression of EGFR was significantly increased in glioma cells and tissues, which was negatively correlated with microRNA-374b expression. Subsequent cell recovery experiment indicated that microRNA-374b and EGFR had a mutual regulation and could affect the malignant progression of glioma all together.

CONCLUSIONS

MicroRNA-374b could inhibit the invasion and migration of glioma by regulating EGFR. Moreover, the expression of microRNA-374b was significantly associated with lymph node metastasis, distant metastasis and poor prognosis.

Emerging roles and potential clinical applications of noncoding RNAs in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the most common forms of cancer, and accounts for a high proportion of cancer-associated deaths. Growing evidences have demonstrated that non- protein-coding regions of the genome could give rise to transcripts, termed noncoding RNA (ncRNA), that form novel functional layers of the cellular activity. ncRNAs are implicated in different molecular mechanisms and functions at transcriptional, translational and post-translational levels. An increasing number of studies have demonstrated a complex array of molecular and cellular functions of ncRNAs in different stages of the HCC tumorigenesis, either in an oncogenic or tumor-suppressive manner. As a result, several pre-clinical studies have highlighted the great potentials of ncRNAs as novel biomarkers for cancer diagnosis or therapeutics in targeting HCC progression. In this review, we briefly described the characteristics of several representative ncRNAs and summarized the latest findings of their roles and mechanisms in the development of HCC, in order to better understand the cancer biology and their potential clinical applications in this malignancy.

Characterization of DNA Methylation Patterns and Mining of Epigenetic Markers During Genomic Reprogramming in SCNT Embryos

Somatic cell nuclear transfer (SCNT), also known as somatic cell cloning, is a commonly used technique to study epigenetic reprogramming. Although SCNT has the advantages of being safe and able to obtain pluripotent cells, early developmental arrest happens in most SCNT embryos. Overcoming epigenetic barriers is currently the primary strategy for improving reprogramming efficiency and improving developmental rate in SCNT embryos. In this study, we analyzed DNA methylation profiles of in vivo fertilized embryos and SCNT embryos with different developmental fates. Overall DNA methylation level was higher in SCNT embryos during global de-methylation process compared to in vivo fertilized embryos. In addition, promoter region, first intron and 3′UTR were found to be the major genomic regions that were hyper-methylated in SCNT embryos. Surprisingly, we found the length of re-methylated region was directly related to the change of methylation level. Furthermore, a number of genes including Dppa2 and Dppa4 which are important for early zygotic genome activation (ZGA) were not properly activated in SCNT embryos. This study comprehensively analyzed genome-wide DNA methylation patterns in SCNT embryos and provided candidate target genes for improving efficiency of genomic reprogramming in SCNT embryos. Since SCNT technology has been widely used in agricultural and pastoral production, protection of endangered animals, and therapeutic cloning, the findings of this study have significant importance for all these fields.

The Fluidity of the Bacterial Outer Membrane Is Species Specific: Bacterial Lifestyles and the Emergence of a Fluid Outer Membrane

The outer membrane (OM) is an essential barrier that guards Gram-negative bacteria from diverse environmental insults. Besides functioning as a chemical gatekeeper, the OM also contributes towards the strength and stiffness of cells and allows them to sustain mechanical stress. Largely influenced by studies of Escherichia coli, the OM is viewed as a rigid barrier where OM proteins and lipopolysaccharides display restricted mobility. Here the discussion is extended to other bacterial species, with a focus on Myxococcus xanthus. In contrast to the rigid OM paradigm, myxobacteria possess a relatively fluid OM. It is concluded that the fluidity of the OM varies across environmental species, which is likely linked to their evolution and adaptation to specific ecological niches. Importantly, a fluid OM can endow bacteria with distinct functions for cell-cell and cell-environment interactions.

Qualitative and quantitative measures of prefemoral and quadriceps fat pads are associated with incident radiographic osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVE

To determine if qualitative and quantitative measures of prefemoral fat pad (PFP) and quadriceps fat pad (QFP) are associated with incident radiographic osteoarthritis (iROA) over 4 years in the Osteoarthritis Initiative (OAI) study.

DESIGN

Participants in this nested case-control study were selected from the OAI study with knees that had Kellgren Lawrence grades (KLG) of 0 or 1 at baseline. Case knees were defined by iROA (KLG≥ 2) over 4 years. Control knees without iROA were matched 1:1 with case knees. Magnetic resonance images (MRIs) were read at P0 (time of onset of iROA), P-1 (1 year prior to P0) and baseline, and used to assess PFP (i.e., prefemoral hyperintensity alteration, patellofemoral hyperintensity alteration, maximum axial area) and QFP (i.e., hyperintensity alteration, mass effect, maximum axial area). Conditional logistic regression analyses were performed to study the associations between PFP/QFP measures and iROA, after adjustment for covariates.

RESULTS

354 case knees with iROA were matched to 354 control knees. 66.9% of the participants were female, with an average age of 60.1 years. PFP prefemoral hyperintensity alteration measured at three time points (OR [95%CI]: 1.46 [1.18-1.82], 1.50 [1.20-1.88], 1.52 [1.22-1.89] respectively), PFP maximum axial area (OR [95%CI]: 1.07 [1.01-1.14], 1.08 [1.01-1.15], 1.08 [1.02-1.15] respectively) and QFP hyperintensity alteration (OR [95%CI]: 1.59 [1.27-2.00], 1.44 [1.13-1.82], 1.38 [1.09-1.73] respectively) were significantly associated with iROA in multivariable conditional logistic analyses. QFP mass effect measured at BL and P-1 (OR [95%CI]: 1.42 [1.11-1.82], 1.33 [1.01-1.73] respectively) were significantly associated with iROA.

CONCLUSIONS

Qualitative and quantitative measures of PFP and QFP are associated with increased iROA over 4 years.