Cellular & Molecular Biology Letters最新文献

Background: Disorders of lipid metabolism are critical factors in the progression of chronic lymphocytic leukemia (CLL). However, the characteristics of lipid metabolism and related regulatory mechanisms of CLL remain unclear.

Methods: Hence, we identified altered metabolites and aberrant lipid metabolism pathways in patients with CLL by ultra-high-performance liquid chromatography-mass spectrometry-based non-targeted lipidomics. A combination of transcriptomics and lipidomics was used to mine relevant target molecule and downstream signaling pathway. In vitro cellular assays, quantitative real-time polymerase chain reaction (qRT-PCR), western blot, fluorescent staining, RNA sequencing, and coimmunoprecipitation were used to monitor the molecular levels as well as to explore the underlying mechanisms.

Results: Significant differences in the content of 52 lipid species were identified in CLL samples and healthy controls. Functional analysis revealed that alterations in glycerolipid metabolism, glycerophospholipid metabolism, sphingolipid metabolism, and metabolic pathways had the greatest impact on CLL. On the basis of the area under the curve value, a combination of three metabolites (phosphatidylcholine O-24:2_18:2, phosphatidylcholine O-35:3, and lysophosphatidylcholine 34:3) potentially served as a biomarker for the diagnosis of CLL. Furthermore, utilizing integrated lipidomic, transcriptomic, and molecular studies, we reveal that ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) plays a crucial role in regulating oncogenic lipogenesis. ENPP2 expression was significantly elevated in patients with CLL compared with normal cells and was validated in an independent cohort. Moreover, ENPP2 knockdown and targeted inhibitor PF-8380 treatment exerted an antitumor effect by regulating cell viability, proliferation, apoptosis, cell cycle, and enhanced the drug sensitivity to ibrutinib. Mechanistically, ENPP2 inhibited AMP-activated protein kinase (AMPK) phosphorylation and promoted lipogenesis through the sterol regulatory element-binding transcription factor 1 (SREBP-1)/fatty acid synthase (FAS) signaling pathway to promote lipogenesis.

Conclusions: Taken together, our findings unravel the lipid metabolism characteristics of CLL. Moreover, we demonstrate a previously unidentified role and mechanism of ENPP2 in regulation of lipid metabolism, providing a novel therapeutic target for CLL treatment.

Background: Radiotherapy for pelvic malignant tumors inevitably causes intestinal tissue damage. The regeneration of intestinal epithelium after radiation injury relies mainly on crypt fission. However, little is known about the regulatory mechanisms of crypt fission events.

Methods: The effects of WNT4 on crypt regeneration and the symmetry of crypt fission were examined using a mouse small intestinal organoid culture model. Three-dimensional (3D) reconstructed images of organoids were applied to assess the symmetry of crypt fission and Paneth cell localization upon manipulation of WNT4 expression. The effect of WNT4 on the expression of β-catenin target genes was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). The in vivo effect of WNT4 overexpression mediated by adeno-associated virus (AAV) on symmetric fission of crypt was investigated using a radiation-injured mouse model.

Results: WNT4 has a special function of promoting symmetric fission of small intestinal crypts, although it inhibits budding, stemness, and cell proliferation on organoids. WNT4 promotes the correct localization of Paneth cells in the crypt base by regulating the expression of EphB3, thereby promoting the symmetric fission of small intestinal crypts. WNT4 negatively regulates the canonical WNT/β-catenin signaling pathway, and it promotes symmetric crypt fission in a ROR2 receptor-dependent manner. Moreover, in patients and animal models of radiation-induced intestinal injury, we found that the regenerated crypts are irregular in size and shape, Paneth cells are mislocalized, and the expression of WNT4 is decreased while EphB3 is increased. Importantly, restoration of WNT4 expression mediated by AAV effectively promotes symmetric crypt fission and thus improves the regularity of regenerating crypts in mice with radiation-induced injury.

Conclusions: Our study highlights the critical role of WNT4 in the regulation of crypt fission and provides WNT4 as a potential therapeutic target for radiation enteritis.

Gastric cancer (GC) represents a prevalent malignancy globally, often diagnosed at advanced stages owing to subtle early symptoms, resulting in a poor prognosis. Exosomes are extracellular nano-sized vesicles and are secreted by various cells. Mounting evidence indicates that exosomes contain a wide range of molecules, such as DNA, RNA, lipids, and proteins, and play crucial roles in multiple cancers including GC. Recently, with the rapid development of mass spectrometry-based detection technology, researchers have paid increasing attention to exosomal cargo proteins. In this review, we discussed the origin of exosomes and the diagnostic and prognostic roles of exosomal proteins in GC. Moreover, we summarized the biological functions of exosomal proteins in GC processes, such as proliferation, metastasis, drug resistance, stemness, immune response, angiogenesis, and traditional Chinese medicine therapy. In summary, this review synthesizes current advancements in exosomal proteins associated with GC, offering insights that could pave the way for novel diagnostic and therapeutic strategies for GC in the foreseeable future.

Aberrant elongation of proteins can lead to the activation of oncogenic signaling pathways, resulting in the dysregulation of oncogenic signaling pathways. Eukaryotic elongation factor 2 (eEF2) is an essential regulator of protein synthesis that precisely elongates nascent peptides in the protein elongation process. Although studies have linked aberrant eEF2 expression to various cancers, research has primarily focused on its structure, highlighting a need for deeper exploration into its molecular functions. In this review, recent advancements in the structure, guanosine triphosphatase (GTPase) activity, posttranslational modifications, regulatory factors, and inhibitors of eEF2 are summarized. These findings provide a comprehensive cognition on the critical role of eEF2 and its potential as a therapeutic target in cancer. Furthermore, this review highlights important unanswered questions that warrant investigation in future research.

Mitochondria are versatile and complex organelles that can continuously communicate and interact with the cellular milieu. Deregulated communication between mitochondria and host cells/organelles has significant consequences and is an underlying factor of many pathophysiological conditions, including the process of aging. During aging, mitochondria lose function, and mitocellular communication pathways break down; mitochondrial dysfunction interacts with mitochondrial dyscommunication, forming a vicious circle. Therefore, strategies to protect mitochondrial function and promote effective communication of mitochondria can increase healthy lifespan and longevity, which might be a new treatment paradigm for age-related disorders. In this review, we comprehensively discuss the signal transduction mechanisms of inter- and intracellular mitochondrial communication, as well as the interactions between mitochondrial communication and the hallmarks of aging. This review emphasizes the indispensable position of inter- and intracellular mitochondrial communication in the aging process of organisms, which is crucial as the cellular signaling hubs. In addition, we also specifically focus on the status of mitochondria-targeted interventions to provide potential therapeutic targets for age-related diseases.

Background: Maternal overnutrition, prevalent among women of childbearing age, significantly impacts offspring health throughout their lifetime. While DNA methylation of metabolic-related genes mediates the transmission of detrimental effects from maternal high-fat diet (HFD), its role in programming hepatic cholesterol metabolism in offspring, particularly during weaning, remains elusive.

Methods: Female C57BL/6 J mice were administered a HFD or control diet, before and during, gestation and lactation. Hepatic cholesterol metabolism genes in the liver of offspring were evaluated in terms of their expression. The potential regulator of cholesterol metabolism in the offspring's liver was identified, and the function of the targeted transcription factor was evaluated through in vitro experiments. The methylation level of the target transcription factor was assessed using the MassARRAY EpiTYPER platform. To determine whether transcription factor expression is influenced by DNA methylation, in vitro experiments were performed using 5-azacitidine and Lucia luciferase activity assays.

Results: Here, we demonstrate that maternal HFD results in higher body weight and hypercholesterolemia in the offspring as early as weaning age. Maternal HFD feeding exacerbates hepatic cholesterol accumulation in offspring primarily by inhibiting cholesterol elimination to bile acids, with a significant decrease of hepatic cholesterol 7α-hydroxylase (CYP7A1). RNA-seq analysis identified myocyte enhancer factor 2A (MEF2A) as a key transcription factor in the offspring liver, which was significantly downregulated in offspring of HFD-fed dams. MEF2A knockdown led to CYP7A1 downregulation and lipid accumulation in HepG2 cells, while MEF2A overexpression reversed this effect. Dual luciferase reporter assays confirmed direct modulation of CYP7A1 transcription by MEF2A. Furthermore, the reduced MEF2A expression was attributed to DNA hypermethylation in the Mef2a promoter region. This epigenetic modification manifested as early as the fetal stage.

Conclusions: This study provides novel insights into how maternal HFD orchestrates hepatic cholesterol metabolism via MEF2A hypermethylation-mediated CYP7A1 suppression in offspring at weaning.

Pulmonary hypertension (PH) presents a puzzling sex bias, being more prevalent in women yet often less severe than in men, and the underlying reasons remain unclear. Studies using animal models, and limited clinical data have revealed a protective influence of exogenous estrogens, known as the estrogen paradox. Research suggests that beyond its receptor-mediated effects, estrogen acts through metabolites such as 2-ME2, 4-OHE2, and 16-OHE2, which are capable of exhibiting protective or detrimental effects in PH, prompting the need to explore their roles in PH to untangle sex differences and the estrogen paradox. Hypoxia disrupts the balance of estrogen metabolites by affecting the enzymes responsible for estrogen metabolism. Delving into the role of these metabolic enzymes not only illuminates the sex difference in PH but also provides a potential rationale for the estrogen paradox. This review delves into the intricate interplay between estrogen metabolites, metabolic enzymes, and PH, offering a deeper understanding of sex-specific differences and the perplexing estrogen paradox in the context of this condition.

Background: The role of proximal tubular autophagy in repairing kidney injury following ischemia remains unclear.

Methods: In this study, we utilized mice with conditional deletion of the Atg5 gene in proximal tubules and monitored the long-term dynamic regulation of autophagy following ischemic acute kidney injury (AKI).

Results: The results showed that Atg5-deficient proximal tubule epithelial cells exhibited damaged mitochondria, concentric membranes, and lysosomal accumulation 24 h after ischemia/reperfusion. However, 28 days after ischemia/reperfusion, concentric membrane bodies remained, but lysosomal accumulation was no longer observed. Notably, the absence of Atg5 in renal tubular epithelial cells impaired renal function and led to increased tubular cell proliferation and oxidative stress in the early stage of injury. However, during the repair period following AKI, Atg5 deficiency exhibited no significant difference in the expression of proliferating cell nuclear antigen (PCNA) and 4-hydoxynonenal (4HNE), suggesting that the improvement in renal fibrosis associated with Atg5 deficiency is unlikely to result from its effect on cell proliferation or reactive oxygen species levels. Additionally, Atg5 deficiency inhibits the secretion of profibrotic factor fibroblast growth factor 2 (FGF2) from the early stage of renal injury to the recovery stage of AKI, indicating that autophagy-specific regulation of FGF2 secretion is a dynamic process overlapping with other stages of injury. Furthermore, increased co-localization of ATG5 with 4HNE and FGF2 was observed in patient samples.

Conclusion: In summary, our results suggest that the dynamic regulation of autophagy on key molecules involved in kidney injury and repair varies with the stage of kidney injury.

Background: Myoblast fusion plays a crucial role in myogenesis. Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) functions as an RNA N⁶-methyladenosine reader and exerts important roles in various biological processes. While our prior study suggested Igf2bp3 contributes to myogenesis, its molecular regulatory mechanism is largely unclear.

Methods: Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were used for gene expression analysis. siRNA and CRISPRi technologies were conducted to knockdown the expression of Igf2bp3. CRISPR/Cas9 technology was performed to knockout Igf2bp3. The Igf2bp3 overexpression vector was designed using the pcDNA3.1(+) vector. Immunofluorescence detection was employed for subcellular localization and cell differentiation analysis. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays were conducted for cell proliferation and fusion detection. The dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized for regulatory mechanism analysis of Igf2bp3.

Results: The overexpression of Igf2bp3 enhances myoblast fusion while knockdown of Igf2bp3 blocks the formation of myotubes. miR-6240 promotes myoblast proliferation while preventing myoblast differentiation and fusion by targeting the 3' untranslated rgion (UTR) of Igf2bp3. Notably, the impacts of miR-6240 mimics on myoblast proliferation, differentiation, and fusion can be effectively counteracted by the overexpression of Igf2bp3. Moreover, our findings elucidate a direct interaction between Igf2bp3 and the myoblast fusion factor myomaker (Mymk). Igf2bp3 binds to Mymk to enhance its mRNA stability. This interaction results in increased expression of Mymk and heightened myoblast fusion.

Conclusions: Our study unveils Igf2bp3 as a novel post-transcriptional regulator of myoblast fusion through the miR-6240/Mymk axis, significantly contributing to our understanding of skeletal muscle development.