Loss of UBE2S causes meiosis I arrest with normal spindle assembly checkpoint dynamics in mouse oocytes.

The timely degradation of proteins that regulate the cell cycle is essential for oocyte maturation. Oocytes are equipped to degrade proteins via the ubiquitin-proteasome system. In meiosis, anaphase promoting complex/cyclosome (APC/C), an E3 ubiquitin-ligase, is responsible for the degradation of proteins. Ubiquitin-conjugating enzyme E2 S (UBE2S), an E2 ubiquitin-conjugating enzyme, delivers ubiquitin to APC/C. APC/C has been extensively studied, but the functions of UBE2S in oocyte maturation and mouse fertility are not clear. In this study, we used Ube2s knockout mice to explore the role of UBE2S in mouse oocytes. Ube2s-deleted oocytes were characterized by meiosis I arrest with normal spindle assembly and spindle assembly checkpoint dynamics. However, the absence of UBE2S affected the activity of APC/C. Cyclin B1 and securin are two substrates of APC/C, and their levels were consistently high, resulting in the failure of homologous chromosome separation. Unexpectedly, the oocytes arrested in meiosis I could be fertilized and the embryos could become implanted normally, but died before embryonic day 10.5. In conclusion, our findings reveal an indispensable regulatory role of UBE2S in mouse oocyte meiosis and female fertility.

GhTCE1-GhTCEE1 dimers regulate transcriptional reprogramming during wound-induced callus formation in cotton.

Wounded plant cells can form callus to seal the wound site. Alternatively, wounding can cause adventitious organogenesis or somatic embryogenesis. These distinct developmental pathways require specific cell fate decisions. Here, we identify GhTCE1, a basic helix-loop-helix family transcription factor, and its interacting partners as a central regulatory module of early cell fate transition during in vitro dedifferentiation of cotton (Gossypium hirsutum). RNAi- or CRISPR/Cas9-mediated loss of GhTCE1 function resulted in excessive accumulation of reactive oxygen species (ROS), arrested callus cell elongation, and increased adventitious organogenesis. In contrast, GhTCE1-overexpressing tissues underwent callus cell growth, but organogenesis was repressed. Transcriptome analysis revealed that several pathways depend on proper regulation of GhTCE1 expression, including lipid transfer pathway components, ROS homeostasis, and cell expansion. GhTCE1 bound to the promoters of the target genes GhLTP2 and GhLTP3, activating their expression synergistically, and the heterodimer TCE1-TCEE1 enhances this activity. GhLTP2- and GhLTP3-deficient tissues accumulated ROS and had arrested callus cell elongation, which was restored by ROS scavengers. These results reveal a unique regulatory network involving ROS and lipid transfer proteins, which act as potential ROS scavengers. This network acts as a switch between unorganized callus growth and organized development during in vitro dedifferentiation of cotton cells.

Efficient Capture and Release of the Rare-Earth Element Neodymium in Aqueous Solution by Recyclable Covalent Organic Frameworks.

Rare-earth elements (REEs) are present in a broad range of critical materials. The development of solid adsorbents for REE capture could enable the cost-effective recycling of REE-containing magnets and electronics. In this context, covalent organic frameworks (COFs) are promising candidates for REE adsorption due to their exceptionally high surface area. Despite having attractive physical properties, COFs are heavily underutilized for REE capture applications due to their limited lifecycle in aqueous acidic environments, as well as synthetic challenges associated with the incorporation of ligands suitable for REE capture. Here, we show how the Ugi multicomponent reaction can be leveraged to postsynthetically modify imine-based COFs for the introduction of a diglycolic acid (DGA) moiety, an efficient scaffold for REE capture. The adsorption capacity of the DGA-functionalized COF was found to be more than 40 times higher than that of the pristine imine COF precursor and more than four times higher than that of the next-best reported DGA-functionalized solid support. This rationally designed COF has appealing characteristics of high adsorption capacity, fast and efficient capture and release of the REE ions, and reliable recyclability, making it one of the most promising adsorbents for solid-liquid REE ion extractions reported to date.

Sorbremnoids A and B: NLRP3 Inflammasome Inhibitors Discovered from Spatially Restricted Crosstalk of Biosynthetic Pathways.

Crosstalk-oriented chemical evolution of natural products (NPs) is an efficacious strategy for generating novel skeletons through coupling reactions between NP fragments. In this study, two NOD-like receptor protein 3 (NLRP3) inflammasome inhibitors, sorbremnoids A and B (1 and 2), with unprecedented chemical architectures were identified from a fungus Penicillium citrinum. Compounds 1 and 2 exemplify rare instances of hybrid NPs formed via a major facilitator superfamily (MFS)-like enzyme by coupling reactive intermediates from two separate biosynthetic gene clusters (BGCs), pcisor and pci56. Both sorbremnoids A and B are NLRP3 inflammasome inhibitors. Sorbremnoid A demonstrated strong inhibition of IL-1ß by directly binding to the NLRP3 protein, inhibiting the assembly and activation of the NLRP3 inflammasome in vitro, with potential application in diabetic refractory wound healing through the suppression of excessive inflammatory responses. This research will inspire the development of anti-NLRP3 inflammasome agents as lead treatments and enhance knowledge pertaining to NPs derived from biosynthetic crosstalk.

Design, synthesis and biological evaluation of novel diphenylamine analogues as NLRP3 inflammasome inhibitors.

The aberrant activation of the NLRP3 inflammasome has been implicated in the pathogenesis of numerous inflammation-related diseases. Development of NLRP3 inflammasome inhibitors is expected to provide a new strategy for the treatment of these diseases. Herein, a novel series of diphenylamine derivatives were designed based on the lead compounds H20 and H28, and the preliminary structure-activity relationship was studied. The representative compound 19 displayed significantly higher inhibitory activity against NLRP3 inflammasome compared to lead compounds H20 and H28, with an IC50 of 0.34 µM. Mechanistic studies indicated that compound 19 directly targets the NLRP3 protein (KD: 0.45 µM), blocking the assembly and activation of the NLRP3 inflammasome, leading to anti-inflammatory effects and inhibition of cellular pyroptosis. Our findings indicated that compound 19 is a promising NLRP3 inhibitor and could potentially serve as a lead compound for further optimization.

Discovery of novel biphenyl-sulfonamide analogues as NLRP3 inflammasome inhibitors.

The aberrant activation of NLRP3 inflammasome has been observed in various human diseases. Targeting the NLRP3 protein with small molecule inhibitors shows immense potential as an effective strategy for disease intervention. Herein, a series of novel biphenyl-sulfonamide NLRP3 inflammasome inhibitors were designed and synthesized. The representative compound H28 was identified as potent and specific NLRP3 inflammasome inhibitor with IC50 values of 0.57 µM. Preliminary mechanistic studies have revealed that compound H28 exhibits direct binding to the NLRP3 protein (KD: 1.15 µM), effectively inhibiting the assembly and activation of the NLRP3 inflammasome. The results in a mouse acute peritonitis model revealed that H28 effectively inhibit the NLRP3 inflammasome pathway, demonstrating their anti-inflammatory properties. Our findings strongly support the further development of H28 as potential lead compound for treating NLRP3-related diseases.

SRSF2 is required for mRNA splicing during spermatogenesis.

BACKGROUND: RNA splicing plays significant roles in fundamental biological activities. However, our knowledge about the roles of alternative splicing and underlying mechanisms during spermatogenesis is limited. RESULTS: Here, we report that Serine/arginine-rich splicing factor 2 (SRSF2), also known as SC35, plays critical roles in alternative splicing and male reproduction. Male germ cell-specific deletion of Srsf2 by Stra8-Cre caused complete infertility and defective spermatogenesis. Further analyses revealed that deletion of Srsf2 disrupted differentiation and meiosis initiation of spermatogonia. Mechanistically, by combining RNA-seq data with LACE-seq data, we showed that SRSF2 regulatory networks play critical roles in several major events including reproductive development, spermatogenesis, meiotic cell cycle, synapse organization, DNA recombination, chromosome segregation, and male sex differentiation. Furthermore, SRSF2 affected expression and alternative splicing of Stra8, Stag3 and Atr encoding critical factors for spermatogenesis in a direct manner. CONCLUSIONS: Taken together, our results demonstrate that SRSF2 has important functions in spermatogenesis and male fertility by regulating alternative splicing.

Discovery, Total Synthesis, and Anti-Inflammatory Evaluation of Naturally Occurring Naphthopyrone-Macrolide Hybrids as Potent NLRP3 Inflammasome Inhibitors.

Numerous clinical disorders have been linked to the etiology of dysregulated NLRP3 (NACHT, LRR, and PYD domain-containing protein 3) inflammasome activation. Despite its potential as a pharmacological target, modulation of NLRP3 activity remains challenging. Only a sparse number of compounds have been reported that can modulate NLRP3 and none of them have been developed into a commercially available drug. In this research, we identified three potent NLRP3 inflammasome inhibitors, gymnoasins A-C (1-3), with unprecedented pentacyclic scaffolds, from an Antarctic fungus Pseudogymnoascus sp. HDN17-895, which represent the first naturally occurring naphthopyrone-macrolide hybrids. Additionally, biomimetic synthesis of gymnoasin A (1) was also achieved validating the chemical structure and affording ample amounts of material for exhaustive bioactivity assessments. Biological assays indicated that 1 could significantly inhibited in vitro NLRP3 inflammasome activation and in vivo pro-inflammatory cytokine IL-1ß release, representing a valuable new lead compound for the development of novel therapeutics with the potential to inhibit the NLRP3 inflammasome.

General Strategy for Incorporation of Functional Group Handles into Covalent Organic Frameworks via the Ugi Reaction.

The library of imine-linked covalent organic frameworks (COFs) has grown significantly over the last two decades, featuring a variety of morphologies, pore sizes, and applications. An array of synthetic methods has been developed to expand the scope of the COF functionalities; however, most of these methods were designed to introduce functional scaffolds tailored to a specific application. Having a general approach to diversify COFs via late-stage incorporation of functional group handles would greatly facilitate the transformation of these materials into platforms for a variety of useful applications. Herein, we report a general strategy to introduce functional group handles in COFs via the Ugi multicomponent reaction. To demonstrate the versatility of this approach, we have synthesized two COFs with hexagonal and kagome morphologies. We then introduced azide, alkyne, and vinyl functional groups, which could be readily utilized for a variety of post-synthetic modifications. This facile approach enables the functionalization of any COFs containing imine linkages.

MAPRE2 regulates the first meiotic progression in mouse oocytes.

Microtubule plus-end tracking proteins (+TIPs) associate with growing microtubule plus ends and control microtubule dynamics and interactions with different cellular structures during cell division, cell migration and morphogenesis. Microtubule-associated RP/EB family member 2 (MAPRE2/EB2) is a highly conserved core component of +TIPs networks, but whether this molecule is required for mammalian meiotic progression is unknown. In this study, we investigated the expression and function of MAPRE2 during oocyte maturation. Our results showed that MAPRE2 was consistently expressed from germinal vesicle (GV) to metaphase II (MII) stages and that MAPRE2 was distributed in the cytoplasm of oocytes at GV stage and along the spindle at metaphase I (MI) and MII stages. Small interfering RNA-mediated knockdown of Mapre2 severely impaired microtubule stability, kinetochore-microtubule attachment, and chromosome alignment and subsequently caused spindle assembly checkpoint (SAC) activation and cyclin B1 nondegradation, leading to failure of chromosome segregation and first polar body extrusion. This study demonstrates for the first time that MAPRE2 plays an important role during mouse oocyte meiosis.

Discovery of a Novel Ubenimex Derivative as a First-in-Class Dual CD13/Proteasome Inhibitor for the Treatment of Cancer.

The CD13 inhibitor ubenimex is used as an adjuvant drug with chemotherapy for the treatment of cancer due to its function as an immunoenhancer, but it has limitations in its cytotoxic efficacy. The proteasome inhibitor ixazomib is a landmark drug in the treatment of multiple myeloma with a high anti-cancer activity. Herein, we conjugated the pharmacophore of ubenimex and the boric acid of ixazomib to obtain a dual CD13 and proteasome inhibitor 7 (BC-05). BC-05 exhibited potent inhibitory activity on both human CD13 (IC50 = 0.13 µM) and the 20S proteasome (IC50 = 1.39 µM). Although BC-05 displayed lower anti-proliferative activity than that of ixazomib in vitro, an advantage was established in the in vivo anti-cancer efficacy and prolongation of survival time, which may be due to its anti-metastatic and immune-stimulating activity. A pharmacokinetic study revealed that BC-05 is a potentially orally active agent with an F% value of 24.9%. Moreover, BC-05 showed more favorable safety profiles than those of ixazomib in preliminary toxicity studies. Overall, the results indicate that BC-05 is a promising drug candidate for the treatment of multiple myeloma.

Diverse and chemoselective sigmatropic shift rearrangements of multisubstituted N,O-diarylhydroxylamines.

N,O-Diarylhydroxylamines generally favor the [3,3] sigmatropic shift rearrangement. Possible N/O[1,3] sigmatropic shift rearrangements of multisubstituted N,O-diarylhydroxylamines were investigated experimentally with rationally designed substrates, which were generally in situ prepared from suitable nitroaryl halides and N-arylhydroxylamines via aromatic nucleophilic substitution. The results indicate that both N- and O-(2,4,6-trimethylphenyl)hydroxylamines still favor the [3,3] sigmatropic shift followed by tautomerization rather than N[1,3] and O[1,3] sigmatropic shifts and the rearranged products of N-(2,4,6-trimethylphenyl)hydroxylamines further undergo an intramolecular nucleophilic addition to afford dibenzo[b,d]furan-4a(9bH)-amine derivatives, while N-(4-mono- and 3,5-disubstituted phenyl)-O-(2,4,6-trinitrophenyl)hydroxylamines favorably first undergo the O[1,3] sigmatropic shift followed by tandem Smiles rearrangement and amide/ester exchange reactions, generating 2-arylaminoaryl benzoate derivatives. N-Phenyl-O-(2,4,6-trinitrophenyl)hydroxylamines undergo tandem double O[1,3] sigmatropic shift rearrangement to produce formal O[1,5] shift products. However, O-(2,6-dinitrophenyl)-N-(4-substituted phenyl)hydroxylamines undergo tandem O[1,3] and double [3,3] sigmatropic shift rearrangements to give formal 3,5-shift products. The proposed mechanism is rationalized by density functional theory (DFT) calculations. The current investigation provides not only a comprehensive understanding of the chemoselective sigmatropic shift rearrangements of N,O-diarylhydroxylamines, but also some novel synthetic strategies for dibenzo[b,d]furanamines, diarylamines, diaryl ethers, 2'-amino-[1,1'-biphenyl]-2(1H)-one, and 2'-amino-[1,1'-biaryl]-4-ol derivatives.

A panel of differentially methylated regions enable prognosis prediction for colorectal cancer.

We aim to identify a panel of differentially methylated regions (DMRs) for predicting survival outcomes for patients with CRC from the TCGA (n = 393). Four DMRs (MUC12, TBX20, CHN2, and B3GNT7) were selected as candidate prognostic markers for CRC. The prediction potential of selected DMRs was validated by the targeted bisulfite sequencing method in an independent cohort with 251 Chinese CRC patients. DMR methylation scores (DMSs) were constructed to evaluate the prognosis of CRC. Results of the validation cohort confirmed that higher DMSs were associated with poor overall survival (OS) of CRC, with hazard ratio (HR) value ranged from 1.445 to 2.698 in multivariable Cox models. Patients in the high prognostic index (high-PI) group showed a markedly unfavorable prognosis compared to the low-PI group in both TCGA discovery cohort (HR = 3.508, 95%CI: 2.196-5.604, P < 0.001) and independent validation cohort (HR = 1.912, 95%CI: 1.258-2.907, P = 0.002).

Design, synthesis and antitumor activity evaluation of novel HDAC inhibitors with tetrahydrobenzothiazole as the skeleton.

HDACs as important targets for cancer therapy have attracted extensive attentions. In this work, a series of sixteen hydroxamic acid based HDAC inhibitors were designed and synthesized with 4,5,6,7-tetrahydrobenzothiazole as the structural core. Majority of them exhibited potent inhibitory activities against HDACs and one leading compound 6h was dug out. 6h was proven to be a pan-HDAC inhibitor and displayed high cytotoxicity against seven human cancer cell lines with IC50 values in low micromolar range. 6h could arrest cell cycle in G2/M phase and induce apoptosis in A549 cells. Moreover, compound 6h exhibited remarkable anti-migration and anti-angiogenesis activities. At the same time, 6h was able to elevate the expression of acetylated α-tubulin and acetylated histone H3 in a dose-dependent manner. Docking simulation revealed that 6h fitted well into the active sites of HDAC2 and 6. Finally, compound 6h also exerted potent antitumor effects in an A549 zebrafish xenograft model. Our study demonstrated that compound 6h was a promising candidate for further preclinical studies.

SCTR hypermethylation is a diagnostic biomarker in colorectal cancer.

Diagnostic markers for both colorectal cancer (CRC) and its precursor lesions are lacking. Although aberrant methylation of the secretin receptor (SCTR) gene was observed in CRC, the diagnostic performance has not been evaluated. Therefore, this study aimed to assess and verify the diagnostic value of SCTR methylation of CRC and its precursor lesions through integrating the largest methylation data. The diagnostic performance of SCTR methylation was analyzed in the discovery set from The Cancer Genome Atlas (TCGA) CRC methylation data (N = 440), and verified in a large-scale test set (N = 938) from the Gene Expression Omnibus (GEO). Targeted bisulfite sequencing analysis was developed and applied to detect the methylation status of SCTR in our independent validation set (N = 374). Our findings revealed that the SCTR gene was frequently hypermethylated at its CpG islands in CRC. In the TCGA discovery set, the diagnostic score was constructed using 4 CpG sites (cg01013590, cg20505223, cg07176264, and cg26009192) and achieved high diagnostic performance (area under the ROC curve [AUC] = 0.964). In the GEO test set, the diagnostic score had robust diagnostic ability to distinguish CRC (AUC = 0.948) and its precursor lesions (AUC = 0.954) from normal samples. Moreover, hypermethylation of the SCTR gene was also found in cell-free DNA samples collected from CRC patients, but not in those from healthy controls. In the validation set, consistent results were observed using the targeted bisulfite sequencing array. Our study highlights that hypermethylation at CpG islands of the SCTR gene is a potential diagnostic biomarker in CRCs and its precursor lesions.

The methylation status in GNAS clusters May Be an epigenetic marker for oocyte quality.

During follicle growth, DNA methylation is gradually established, which is important for oocyte developmental competence. Due to the facts that oocytes from prepubertal individuals show reduced developmental outcomes when compared to those from sexually mature individuals, and the fact that oocytes derived from in vitro follicle culture have much lower developmental competence, it is worth exploring whether prepubertal superovulation and in vitro follicle culture will cause changes in DNA methylation imprinting status in oocytes. In this study, we found that the CpG island in maternally imprinted GNAS clusters was hypermethylated in the MII-stage oocytes from sexually mature mice, but was hypomethylated in oocytes from prepuberty individuals. The GNAS clusters in the MII-stage oocytes obtained by in vitro follicle culture showed heterogeneous methylation levels, indicating different qualities of oocytes, however, three other maternally imprinted genes, Peg1, Lot1 and Impact, were all hypermethylated in the MII-stage oocytes derived from both prepubertal superovulation and in vitro follicle culture. Taken together, the findings suggest that the methylation status in GNAS clusters may potentially represent a novel epigenetic marker for oocyte quality detection.

Chemical Upcycling of Polyolefin Plastics Using Structurally Well-defined Catalysts.

Single-use polyolefins are widely used in our daily life and industrial production due to their light weight, low cost, superior stability, and durability. However, the rapid accumulation of plastic waste and low-profit recycling methods resulted in a global plastic crisis. Catalytic hydrogenolysis is regarded as a promising technique, which can effectively and selectively convert polyolefin plastic waste to value-added products. In this perspective, we focus on the design and synthesis of structurally well-defined hydrogenolysis catalysts across mesoscopic, nanoscopic, and atomic scales, accompanied by our insights into future directions in catalyst design for further enhancing catalytic performance. These design principles can also be applied to the depolymerization of other polymers and ultimately realize the chemical upcycling of waste plastics.

Design, synthesis, and biological activity evaluation of novel HDAC3 selective inhibitors for combination with Venetoclax against acute myeloid leukemia.

Histone deacetylases (HDACs) are highly attractive targets in the drug development process, and the development of subtype-selective HDAC inhibitors is the research direction for HDAC inhibitors. As an important member of the HDAC family, HDAC3 has been found to be closely related to the pathological progression of many diseases due to its abnormal expression. In previous studies, we discovered compound 13a, which has potent inhibitory activity against HDAC1, 2, and 3. In this work, we improved the HDAC3 isotype selectivity of 13a, and obtained compound 9c through rational drug design. 9c shows a selectivity of 71 fold for HDAC3 over HDAC1 and can significantly inhibit the proliferation activity of MV4-11 cells in vitro. Furthermore, when combined with Venetoclax, 9c can effectively induce apoptosis in MV4-11 cells in vitro and reduce the expression of anti-apoptotic proteins, the development of HDAC3 selective inhibitors may serve as a potential lead compound to reverse Venetoclax resistance.

Protein phosphatase 4 maintains the survival of primordial follicles by regulating autophagy in oocytes.

In mammalian ovary, the primordial follicle pool serves as the source of developing follicles and fertilizable ova. To maintain the normal length of female reproductive life, the primordial follicles must have adequate number and be kept in a quiescent state before menopause. However, the molecular mechanisms underlying primordial follicle survival are poorly understood. Here, we provide genetic evidence showing that lacking protein phosphatase 4 (PPP4) in oocytes, a member of PP2A-like subfamily, results in infertility in female mice. A large quantity of primordial follicles has been depleted around the primordial follicle pool formation phase and the ovarian reserve is exhausted at about 7 months old. Further investigation demonstrates that depletion of PPP4 causes the abnormal activation of mTOR, which suppresses autophagy in primordial follicle oocytes. The abnormal primordial follicle oocytes are eventually erased by pregranulosa cells in the manner of lysosome invading. These results show that autophagy prevents primordial follicles over loss and PPP4-mTOR pathway governs autophagy during the primordial follicle formation and dormant period.

Evolution and subfunctionalization of CIPK6 homologous genes in regulating cotton drought resistance.

The occurrence of whole-genome duplication or polyploidy may promote plant adaptability to harsh environments. Here, we clarify the evolutionary relationship of eight GhCIPK6 homologous genes in upland cotton (Gossypium hirsutum). Gene expression and interaction analyses indicate that GhCIPK6 homologous genes show significant functional changes after polyploidy. Among these, GhCIPK6D1 and GhCIPK6D3 are significantly up-regulated by drought stress. Functional studies reveal that high GhCIPK6D1 expression promotes cotton drought sensitivity, while GhCIPK6D3 expression promotes drought tolerance, indicating clear functional differentiation. Genetic and biochemical analyses confirm the synergistic negative and positive regulation of cotton drought resistance through GhCBL1A1-GhCIPK6D1 and GhCBL2A1-GhCIPK6D3, respectively, to regulate stomatal movement by controlling the directional flow of K+ in guard cells. These results reveal differentiated roles of GhCIPK6 homologous genes in response to drought stress in upland cotton following polyploidy. The work provides a different perspective for exploring the functionalization and subfunctionalization of duplicated genes in response to polyploidization.