No abstract

No abstract

Extensive epigenetic reprogramming occurs during preimplantation embryo development. However, it remains largely unclear how the drastic epigenetic reprogramming contributes to transcriptional regulatory network during this period. Here, we develop a single-cell multiomics sequencing technology (scNOMeRe-seq) that enables profiling of genome-wide chromatin accessibility, DNA methylation and RNA expression in the same individual cell. We apply this method to depict a single-cell multiomics map of mouse preimplantation development. We find that genome-wide DNA methylation remodeling facilitates the reconstruction of genetic lineages in early embryos. Further, we construct a zygotic genome activation (ZGA)-associated regulatory network and reveal coordination among multiple epigenetic layers, transcription factors and repeat elements that instruct proper ZGA. Cell fates associated cis-regulatory elements are activated stepwise in post-ZGA stages. Trophectoderm (TE)-specific transcription factors play dual roles in promoting the TE program while repressing the inner cell mass (ICM) program during the ICM/TE separation.

Background The births of more than 8 million infants have been enabled globally through assisted reproductive technologies (ARTs), including conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with either fresh embryo transfer (ET) or frozen embryo transfer (FET). However, the safety issue regarding ARTs has drawn growing attention with accumulating observations of rising health risks, and underlying epigenetic mechanisms are largely uncharacterized. Methods In order to clarify epigenetic risks attributable to ARTs, we profiled DNA methylome on 137 umbilical cord blood (UCB) and 158 parental peripheral blood (PPB) samples, histone modifications (H3K4me3, H3K4me1, H3K27me3 and H3K27ac) on 33 UCB samples and transcriptome on 32 UCB samples by reduced representation bisulfite sequencing (RRBS), chromatin immunoprecipitation sequencing (ChIP-seq), and RNA sequencing (RNA-seq), respectively. Findings We revealed that H3K4me3 was the most profoundly impacted by ICSI and freeze-thawing operation compared with the other three types of histone modifications. IVF-ET seemed to introduce less disturbance into infant epigenomes than IVF-FET or ICSI-ET did. ARTs also decreased the similarity of DNA methylome within twin pairs, and we confirmed that ART per se would introduce conservative changes locally through removal of parental effect. Importantly, those unique and common alterations induced by different ART procedures were highly enriched in the processes related to nervous system, cardiovascular system and glycolipid metabolism etc., which was in accordance with those findings in previous epidemiology studies and suggested some unexplored health issues, including in the immune system and skeletal system. Interpretation Different ART procedures can induce local and functional epigenetic abnormalities, especially for DNA methylation and H3K4me3, providing an epigenetic basis for the potential long-term health risks in ART-conceived offspring. Funding sources This study was funded by National Natural Science Foundation of China (81,730,038; 81,521,002), National Key Research and Development Program (2018YFC1004000; 2017YFA0103801; 2017YFA0105001) and Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16020703). Yang Wang was supported by Postdoctoral Fellowship of Peking-Tsinghua Center for Life Science.

Liquiritigenin (LQ) is a flavanone extracted from glycyrrhizae. Previous studies have demonstrated that LQ possesses antimigration properties in HELA and A549 cells. The present research, as an extension of our earlier ones, investigated whether LQ can enhance the antimigration and antiinvasion effect of cis-diamine dichloroplatinum (CDDP) in B16F10 melanoma cell. The data indicated that LQ (25, 50, 100, 200 μM) combined with CDDP (2 μM) significantly reduced B16F10 cell viability compared to CDDP (2 μM)-treated only. The different doses of LQ combined with CDDP significantly suppressed cell migration (21.5%, 49.6%, 75.6%) and cell invasion (26.2%, 51.4%, 69.5%) compared with CDDP-treated alone, suggesting that LQ enhance the inhibition action of CDDP on cell migration and invasion. Moreover, LQ/CDDP combination led to the downregulation of protein expression of MMP-2/9, PI3 K, p-AKT, and upregulated PTEN protein level that play an important role in tumor metastasis progression. Further study demonstrated the enhancement effect of LQ on CDDP suppressing lung metastasis in a mice model being inoculated by the B16F10 melanoma cells. In conclusion, the results suggested that LQ plays an intensive role on CDDP suppressing invasion and metastasis through regulating the PI3 K/AKT signal pathway and suppressing the protein expression of MMP-2/9.

Age-dependent ectopic fat accumulation (EFA) in animals contributes to the progression of tissue aging and diseases such as obesity, diabetes, and cancer. However, the primary causes of age-dependent EFA remain largely elusive. Here, we characterize the occurrence of age-dependent EFA in Drosophila and identify HDAC6, a cytosolic histone deacetylase, as a suppressor of EFA. Loss of HDAC6 leads to significant age-dependent EFA, lipid composition imbalance, and reduced animal longevity on a high-fat diet. The EFA and longevity phenotypes are ameliorated by a reduction of the lipid-droplet-resident protein PLIN2. We show that HDAC6 is associated physically with the chaperone protein dHsc4/Hsc70 to maintain the proteostasis of PLIN2. These findings indicate that proteostasis collapse serves as an intrinsic cue to cause age-dependent EFA. Our study suggests that manipulation of proteostasis could be an alternative approach to the treatment of age-related metabolic diseases such as obesity and diabetes.

The mechanism by which misfolded proteins in the endoplasmic reticulum (ER) are retrotranslocated to the cytosol for proteasomal degradation is still poorly understood. Here, we show that importin ␤, a well established nucleocytoplasmic transport protein, interacts with components of the retrotranslocation complex and promotes ER-associated degradation (ERAD). Knockdown of importin ␤ specifically inhibited the degradation of misfolded ERAD substrates but did not affect turnover of non-ERAD proteasome substrates. Genetic studies and in vitro reconstitution assays demonstrate that importin ␤ is critically required for ubiquitination of mutant ␣1-antitrypsin, a luminal ERAD substrate. Furthermore, we show that importin ␤ cooperates with Ran GTPase to promote ubiquitination and proteasomal degradation of mutant ␣1-antitrypsin. These results establish an unanticipated role for importin ␤ in ER protein quality control.Many newly synthesized proteins in the endoplasmic reticulum (ER) 2 fail to fold properly because of transcriptional and translational errors or imbalanced production of accessory subunits (1, 2). Additionally, pathogenic conditions, such as genetic mutations, hypoxia, oxidative stress, ischemia, and disturbance of calcium homeostasis, can also cause proteins to misfold in the ER (3-5). Fortunately, cells have evolved protein quality control systems that can efficiently eliminate misfolded proteins from the ER before they wreak havoc on cells. A major mechanism that recognizes and degrades misfolded and unassembled ER proteins at the ER is the ER-associated degradation (ERAD) pathway (1, 2, 6 -8), which exports misfolded ER proteins into the cytosol for degradation by the ubiquitin proteasome system. ER luminal chaperones and lectins recognize and deliver ERAD substrates to membrane-anchored protein complexes that form putative protein-conducting channels from which the substrates are subsequently retrotranslocated into the cytosol (8, 9). Each of these retrotranslocation complexes usually contains one or more membrane-bound ubiquitin ligases (E3s), which ubiquitinate ERAD substrates en route to the cytosol. In budding yeast, the Hrd1p E3 complex degrades substrates whose lesions reside in either the transmembrane domain or lumen of the ER, whereas the other complex containing the Doa10p E3 disposes of substrates with lesions in their cytosolic domains (10, 11). These ERAD complexes are conserved in mammalian cells, but as expected, the repertoire of E3s for mammalian ERAD is more complex. In addition to the Hrd1p and Doa10p orthologs (Hrd1 and gp78 for Hrd1p and TEB4 for Doa10p) (12-16), several other membrane-bound E3s, such as RMA1/RNF5 (ring finger protein 5), RFP2 (Ret finger protein 2), and TRC8 (translocation in renal cancer from chromosome 8) have been implicated in ERAD (17, 18). In addition, cytosolic E3s, including CHIP (C terminus of Hsc70-interacting protein) (19,20), Parkin (21), and the SCF (Skpl-Cullin-F-box protein family) multisubunit E3 (22), can also be recruited to the cytosolic surf...

Drastic epigenetic reprogramming occurs during human gametogenesis and early embryo development. Advances in low-input and single-cell epigenetic techniques have provided powerful tools to dissect the genome-wide dynamics of different epigenetic molecular layers in these processes. In this review, we focus mainly on the most recent progress in understanding the dynamics of DNA methylation, chromatin accessibility, and histone modifications in human gametogenesis and early embryo development. Deficiencies in remodeling of the epigenomes can cause severe developmental defects, infertility, and long-term health issues in offspring. Aspects of the external environment, including assisted reproductive technology procedures, parental diets, and unhealthy parental habits, may disturb the epigenetic reprogramming processes and lead to an aberrant epigenome in the offspring. Here, we review the current knowledge of the potential risk factors of aberrant epigenomes in humans.