Biochemistry and Cell Biology最新文献

WD repeat domain 4 (WDR4) has been reported to promote tumor metastasis in various cancers. However, its precise function in colorectal cancer (CRC) has not been reported yet. Herein, the expression pattern of WDR4 in CRC was determined by analyzing Gene Expression Omnibus datasets (GSE110225, GSE127069, GSE156355, and GSE184093) and GEPIA online dataset. In vitro and in vivo experiments, including CCK-8, colony formation, flow cytometry, wound healing, transwell assays, and xenograft mouse models, were used to investigate the role of WDR4 in CRC. Firstly, data from Kaplan-Meier database showed that high expression of WDR4 was associated with the poor prognosis of CRC patients. Then, upregulation of WDR4 was confirmed in clinical CRC tissues. In vitro functional experiments suggested that overexpression of WDR4 promoted cell proliferation, migration, and invasion, while knockdown of WDR4 has the opposite effects. Also, the oncogenic role of WDR4 was also verified in in vivo experiments. CO-IP-LC/MS analysis uncovered that glycogen synthase kinase 3β (GSK3β) is the central protein that binds to WDR4. Mechanistically, WDR4 activated the β-catenin pathway by promoting GSK3β phosphorylation. This study demonstrates that WDR4 promotes CRC progression through activating GSK3β/β-catenin pathway, indicating that WDR4 might be a potential therapeutic target for CRC treatment.

Estrogen (E2) regulates the differentiation and proliferation of mammary progenitor cells by modulating the transcription of multiple genes. One of the genes that is downregulated by E2 is SOX2, a transcription factor associated with stem and progenitor cells that is overexpressed during breast tumourigenesis. To elucidate the mechanisms underlying E2-mediated SOX2 repression, we investigated epigenome and transcriptome changes following short- and long-term E2 exposure in breast cancer cells. We found that short-term E2 exposure reduces chromatin accessibility at the downstream SOX2 SRR134 enhancer, decreasing SOX2 expression. In contrast, long-term E2 exposure completely represses SOX2 transcription while maintaining accessibility at the SRR124-134 enhancer cluster, keeping it poised for reactivation. This repression was accompanied by widespread epigenome and transcriptome changes associated with commitment towards a more differentiated and less invasive luminal phenotype. Finally, we identified a role for the transcription factor NFIB in this process, suggesting it collaborates with the estrogen receptor to mediate SOX2 repression and genome-wide epigenome accessibility changes.

Enucleated cells, also known as cytoplasts, are valuable tools with a wide range of applications. However, their potential for bio-engineering is greatly restricted by the short lifespan. We postulated that the enucleation process damages the integrity of the plasma membrane and thus activates a cell death program(s). The results showed that a tiny hole was generated transiently on the plasma membrane when the nucleus was spun off, while force-gated ion channels were activated in response to the pulling by the nucleus. Influx of extracellular calcium stimulated the opening of calcium channels and the release of calcium from endoplasmic reticulum and mitochondria. Long lasting calcium transient increased protein phosphorylation and activated caspase 9 and calpain proteinase activities. Subsequently, mitochondria membrane permeability and Reactive Oxygen Species (ROS) levels were significantly elevated, which eventually led to eryptosis-like cell death. When extracellular calcium was maintained at optimal concentration, the lifespan of enucleated cells was extended; however, huge amounts of vacuoles appeared in the cytoplasm, possibly derived from enlarged autophagosomes. Inhibition of vacuolation by inhibitors of autophagy or in co-culture with primary muscle cells did not rescue cells dying from the paraptosis-like pathway. These results offer valuable insights for further investigation into the intricate mechanisms underlying enucleated cell death.

Abdominal aortic aneurysm (AAA) is a chronic and severe aortic disease. Our previous studies have indicated that monocyte chemotactic protein-induced protein-1 (MCPIP1) is involved in AAA. However, the exact effect of MCPIP1 on angiotensin II (Ang II)-induced AAA formation is currently unknown. MCPIP1 deficiency reduced AAA formation in Ang II-induced mice. Less collagen and elastin degradation were observed in MCPIP1-deficient mice treated with Ang II. Ang II decreased αSMA and SM22α levels in aortas and vascular smooth muscle cells (VSMCs), whereas MCPIP1 deficiency reduced this decrease. MCPIP1 deficiency also attenuated Ang II-induced expression of MAPK signaling-associated proteins in aortas and VSMCs. Silencing MCPIP1 decreased proliferation and migration in Ang II-induced VSMCs. Furthermore, inactivation of ERK1/2 with PD98059 reduced Ang II-induced proliferation and migration of VSMCs. Dual luciferase and chromatin immunoprecipitation assay results confirmed that MCPIP1 was transcriptionally regulated by KLF4. KLF4 knockdown reversed the facilitating effect of Ang II on MCPIP1 expression. In conclusion, our findings suggest that MCPIP1 promotes Ang II-induced VSMCs phenotypic switching via the MAPK signaling pathway.

Chronic inflammation is a driving factor in diseases like obesity and type 2 diabetes. Enhanced cellular glucose metabolism may contribute to heightened immune activation. A human supplementation trial showed that the n-3 PUFA α-linolenic acid (ALA) reduced oxidative phosphorylation in monocytes. Our objective here is to assess the direct effects of ALA and docosahexaenoic acid (DHA) on glucose metabolism in a cell culture model and to explore possible molecular mechanisms. THP-1 monocytes were treated with 10-40 µmol/L of ALA or DHA and compared with vehicle and oleic acid controls. The Seahorse XFe24 and Oroboros O₂k Oxygraph systems were used to approximate catabolic rates in the presence of glucose. Both ALA and DHA reduced oxidative phosphorylation. We identified pyruvate dehydrogenase kinase 4 (PDK4) as a possible mechanistic candidate explaining the effect of DHA. Additionally, both n-3 PUFAs reduced lipopolysaccharides-induced IL-1β production, while only DHA increased reactive oxygen species to a small but significant extent. Our data suggest that ALA and DHA trigger a re-wiring of bioenergetic pathways in monocytes, possibly via the upregulation of PDK4. Given the close relationship between cell metabolism and immune cell activation, this may represent a novel mechanism by which n-3 fatty acids modulate immune function and inflammation.

This study investigates the protective effects of Lycium barbarum polysaccharides (LBPs) on X-ray radiation-induced damage in rat spinal cord neurons (SCNs) and examines whether this protection is mediated through the activation of autophagy. In vitro and in vivo experiments revealed that high-dose radiation significantly reduced SCN viability and colony-forming ability. However, treatment with 40 mg/L LBP markedly increased cell survival and autophagy levels. Immunohistochemistry and Western blot (WB) analyses demonstrated a significant upregulation of autophagy-related proteins, protein 1 light chain 3-II/I and Beclin-1, in the LBP intervention group. In vivo studies further showed that LBP reduced oxidative stress markers, such as malondialdehyde, and enhanced superoxide dismutase activity in spinal cord tissue. These findings indicate that LBP mitigates neuronal damage caused by ionizing radiation via autophagy activation and antioxidative mechanisms, highlighting its potential as a radioprotective agent.

Colorectal cancer (CRC) is a prevalent and malignant tumor of the digestive system, characterized by high incidence and mortality rates. This study aimed to investigate the heterogeneity of the tumor microenvironment (TME) and the involvement of immune cells in CRC. Single-cell RNA sequencing (scRNA-seq) data obtained from the Gene Expression Omnibus database were used to analyze and identify six major cell types across normal, core, and border tumor samples. A total of 27 414 cells from various regions of patients with CRC were selected for subsequent analyses. Cellular interaction analysis revealed that differential signaling pathways between the TME and normal tissues, with several pathways involving interactions between myeloid cells and epithelial cells. Myeloid cells were extracted and classified into six subtypes based on markers identified in the literature. Monocle3 revealed the trajectory of tumor-associated macrophages (TAMs) and identified genes associated with pseudotime. Single-Cell ENrichment analysis for Interpreting Cellular Heterogeneity analysis identified specific regulons and target genes associated with TAMs. This study reanalyzed single-cell RNA-sequencing data and provided insights into the heterogeneity of the TME, particularly in relation to the role of TAMs.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in humans and animals. The study aimed to evaluate the efficacy of bovine lactoferrin (bLf) as an adjuvant combined with AMP (N6) in the treatment of E. coli-induced bacterial enteritis. Firstly, 40 female ICR mice were randomly divided into four groups. The ETEC-A, ETEC-B, and ETEC-C groups were gavaged with 0.2 mL of ETEC K88 at 5 × 10⁹, 5 × 10⁸, and 5 × 10⁷ CFU/mL for three consecutive days, respectively, the CK control group was given PBS. Based on the clinical symptoms and intestinal changes, the optimal model dose of ETEC K88 was determined to be 5 × 10⁸ CFU/mL. Sixty female ICR mice were randomly divided into six groups: CK group (uninfected), NC group (infected and untreated), N6 treatment group (20 mg/kg), bLf treatment group (100 mg/kg), bLf + N6-A treatment group (10 mg/kg N6+100 mg/kg bLf), and bLf + N6-B group (20 mg/kg N6+100 mg/kg bLf). The clinical symptoms, intestinal morphology, inflammatory response and serum metabolites were monitored. The results showed that compared with the NC group, the bLf-N6-A and bLf-N6-B treatment groups had significant reductions in TNF-α and IL-6, significant increases in IL-10, and significant reductions in endotoxin and DAO in plasma (p < 0.05). Meanwhile, the bLf-N6-A and bLf-N6-B treatment groups significantly increased the expression of ZO-1, claudin-1 and occludin, increased the height of small intestinal mucosal villi and VH/CD after ETEC K88-induced intestinal injury (p < 0.05). The combination of bLf and N6 relieved enteritis by balancing intestinal mucosal immunity, improving intestinal morphology and barrier function. BLf combined with N6 can be used as an effective therapeutic strategy for the treatment of bacterial enteritis.

Myocardial dysfunction is a major cause of early mortality after successful cardiopulmonary resuscitation (CPR) following cardiac arrest (CA). Following the return of spontaneous circulation, myocardial ischemia-reperfusion injury can activate the NF-κB pathway, leading to the transcription of inflammatory genes that impair myocardial function. While clinical studies show hydrocortisone (HC) improves outcomes in CA patients during CPR, its specific role in modulating the NF-κB pathway is unclear. In this study, we established an in vitro model by inducing hypoxia/reoxygenation (H/R) injury in H9C2 cardiomyocytes using Na₂S₂O₄, followed by HC treatment. The results showed that HC treatment of H/R-injured cardiomyocytes promoted proliferation, inhibited apoptosis, and suppressed the NF-κB pathway, thereby reducing interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-α) levels. Moreover, inhibition of the NF-κB pathway enhanced the proliferative capacity of H/R cardiomyocytes, decreased apoptosis rates, and reduced IL-6, IL-8, and TNF-α expression levels, with these effects being further amplified by HC treatment. These findings were further supported by in vivo experiments. In conclusion, our study suggests that HC may promote H/R cardiomyocyte proliferation, inhibit apoptosis, and alleviate inflammatory responses by suppressing the NF-κB pathway, providing new evidence to support its potential clinical application in CA management.