Cyclins and CDKs in the regulation of meiosis-specific events

The deubiquitinase Usp7 in Drosophila melanogaster is required for synaptonemal complex maintenance

Meiosis is a form of cell division that is essential to sexually reproducing organisms and is therefore highly regulated. Each event of meiosis must occur at the correct developmental stage to ensure that chromosomes are segregated properly during both meiotic divisions. One unique meiosis-specific structure that is tightly regulated in terms of timing of assembly and disassembly is the synaptonemal complex (SC). While the mechanism(s) for assembly and disassembly of the SC are poorly understood in Drosophila melanogaster, posttranslational modifications, including ubiquitination and phosphorylation, are known to play a role. Here, we identify a role for the deubiquitinase Usp7 in the maintenance of the SC in early prophase and show that its function in SC maintenance is independent of the meiotic recombination process. Using two usp7 shRNA constructs that result in different knockdown levels, we have shown that the presence of SC through early/mid-pachytene is critical for normal levels and placement of crossovers.

Glucagon-like peptide-1 analog liraglutide reduces fat deposition in chicken adipocytes

Previously, we reported that glucagon-like peptide-1 (GLP-1) and its analog liraglutide could inhibit fat de novo synthesis in the liver and reduce abdominal fat accumulation in broiler chickens. Nevertheless, the impact of GLP-1 on adipocyte fat deposition remains enigmatic. This study aimed to investigate the effects of GLP-1, via its analog liraglutide, on chicken chicken adipocytes in vitro. Chemical assays, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot were employed to assess the proliferation, differentiation, and fat deposition of chicken adipocytes. Our findings indicated that liraglutide significantly suppressed cell proliferation and promoted preadipocyte differentiation in comparison to the control group. This was evidenced by elevated triglyceride (TG) content and upregulated mRNA expression of lipogenesis-related enzymes, such as acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), as well as regulators including peroxisome proliferator-activated receptor γ (PPARγ), sterol regulatory element binding protein-1 (SREBP1) and CCAAT/enhancer binding protein α (CEBPα). In mature adipocytes, liraglutide attenuated fat deposition by inhibiting fat de novo synthesis, evidenced by decreased mRNA expression of ACC, FAS, PPARγ, C/EBPα, and SREBP1, and concurrent upregulation of phosphorylated AMP-activated protein kinase (p-AMPK) and phosphorylated ACC (p-ACC). This resulted in reduced accumulation of lipid droplets and TG content in mature adipocytes. Collectively, our findings indicate that liraglutide suppresses the proliferation of preadipocytes, enhances their differentiation, and concurrently inhibits de novo lipogenesis in mature adipocytes. This observation offers profound insights into the mechanisms that underlie liraglutide's anti-adipogenic effects, which could have significant implications for the treatment of obesity in broiler chickens.

Differential phosphorylation of two serine clusters in mouse HORMAD1 during meiotic prophase I progression

Mouse HORMAD1 is a phospho-protein involved in multiple functions during meiotic prophase I. To obtain insight into the significance of its phosphorylation, we generated phospho-specific antibodies against two serine residues, Ser307 and Ser378, representing each of two serine clusters in mouse HORMAD1. The Ser307 phosphorylation is detectable from early leptotene substage in both wild-type and Spo11-/- spermatocytes, indicating that Ser307 is a primary and SPO11-independent phosphorylation site. In contrast, the Ser378 phosphorylation is negligible at earlier substages in wild-type and Spo11-/- spermatocytes. After mid-zygotene substage, the Ser378 phosphorylation is abundant on unsynapsed chromosome axes in wild-type spermatocytes and is detected only in a part of unsynapsed chromosome axes in Spo11-/- spermatocytes. We also generated a non-phosphorylated Ser307-specific antibody and found that Ser307 is phosphorylated on sex chromosome axes but is almost entirely unphosphorylated on desynapsed chromosome axes in diplotene spermatocytes. These results demonstrated a substage-specific phosphorylation status of mouse HORMAD1, which might be associated with multiple substage-specific functions.

Diacylglycerol kinase is a keystone regulator of signaling relevant to the pathophysiology of asthma

Signal transduction by G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immunoreceptors converge at the activation of phospholipase C (PLC) for the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This is a point for second-messenger bifurcation where DAG via protein kinase C (PKC) and IP3 via calcium activate distinct protein targets and regulate cellular functions. IP3 signaling is regulated by multiple calcium influx and efflux proteins involved in calcium homeostasis. A family of lipid kinases belonging to DAG kinases (DGKs) converts DAG to phosphatidic acid (PA), negatively regulating DAG signaling and pathophysiological functions. PA, through a series of biochemical reactions, is recycled to produce new molecules of PIP2. Therefore, DGKs act as a central switch in terminating DAG signaling and resynthesis of membrane phospholipids precursor. Interestingly, calcium and PKC regulate the activation of α and ζ isoforms of DGK that are predominantly expressed in airway and immune cells. Thus, DGK forms a feedback and feedforward control point and plays a crucial role in fine-tuning phospholipid stoichiometry, signaling, and functions. In this review, we discuss the previously underappreciated complex and intriguing DAG/DGK-driven mechanisms in regulating cellular functions associated with asthma, such as contraction and proliferation of airway smooth muscle (ASM) cells and inflammatory activation of immune cells. We highlight the benefits of manipulating DGK activity in mitigating salient features of asthma pathophysiology and shed light on DGK as a molecule of interest for heterogeneous diseases such as asthma.

lncRNAs and cyclin-dependent kinases: Unveiling their critical roles in cancer progression

Long non-coding RNAs (lncRNAs) are a diverse class of RNA molecules that do not code for proteins but play critical roles in gene regulation. One such role involves the modulation of cell cycle progression and proliferation through interactions with cyclin-dependent kinases (CDKs), key regulators of cell division. Dysregulation of CDK activity is a hallmark of cancer, contributing to uncontrolled cell growth and tumor formation. These lncRNA-CDK interactions are part of a complex network of molecular mechanisms underlying cancer pathogenesis, involving various signaling pathways and regulatory circuits. Understanding the interplay between lncRNAs, CDKs, and cancer biology holds promise for developing novel therapeutic strategies targeting these molecular targets for more effective cancer treatment. Furthermore, targeting CDKs, key cell cycle progression and proliferation regulators, offers another avenue for disrupting cancer pathways and overcoming drug resistance. This can open new possibilities for individualized treatment plans and focused therapeutic interventions.

Beta-elemene: A phytochemical with promise as a drug candidate for tumor therapy and adjuvant tumor therapy

BACKGROUND

β-Elemene (IUPAC name: (1 S,2 S,4 R)-1-ethenyl-1-methyl-2,4-bis(prop-1-en-2-yl) cyclohexane), is a natural compound found in turmeric root. Studies have demonstrated its diverse biological functions, including its anti-tumor properties, which have been extensively investigated. However, these have not yet been reviewed. The aim of this review was to provide a comprehensive summary of β-elemene research, with respect to disease treatment.

METHODS

β-Elemene-related articles were found in PubMed, ScienceDirect, and Google Scholar databases to systematically summarize its structure, pharmacokinetics, metabolism, and pharmacological activity. We also searched the Traditional Chinese Medicine System Pharmacology database for therapeutic targets of β-elemene. We further combined these targets with the relevant literature for KEGG and GO analyses.

RESULTS

Studies on the molecular mechanisms underlying β-elemene activity indicate that it regulates multiple pathways, including STAT3, MAPKs, Cyclin-dependent kinase 1/cyclin B, Notch, PI3K/AKT, reactive oxygen species, METTL3, PTEN, p53, FAK, MMP, TGF-β/Smad signaling. Through these molecular pathways, β-elemene has been implicated in tumor cell proliferation, apoptosis, migration, and invasion and improving the immune microenvironment. Additionally, β-elemene increases chemotherapeutic drug sensitivity and reverses resistance by inhibiting DNA damage repair and regulating pathways including CTR1, pak1, ERK1/2, ABC transporter protein, Prx-1 and ERCC-1. Nonetheless, owing to its lipophilicity and low bioavailability, additional structural modifications could improve the efficacy of this drug.

CONCLUSION

β-Elemene exhibits low toxicity with good safety, inhibiting various tumor types via diverse mechanisms in vivo and in vitro. When combined with chemotherapeutic drugs, it enhances efficacy, reduces toxicity, and improves tumor killing. Thus, β-elemene has vast potential for research and development.