Biochemistry and Cell Biology最新文献

Transcription factor SOX2 is essential for a number of biological processes, including mammalian nervous system development and adult brain stem cell maintenance. Expression of this gene requires precise control by a complex network of regulatory elements, which still remains poorly understood. Years of research by different groups have generated a large amount of data on multiple SOX2 enhancers, with varying levels of evidence for their activity across species and tissues. However, the volume of information in the field and inconsistent nomenclature, with the same enhancer referred to by different study-specific names, make understanding progress in SOX2 enhancer regulation challenging. In this review, we brought together current knowledge on predicted and experimentally validated SOX2 enhancers, highlighting links between conserved elements studied in different species. We also propose a unified enhancer naming system based on the distance from the SOX2 transcription start site in the genome of interest, aiming to improve consistency and make communication in the field more straightforward.

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with poor outcomes at advanced stages. Although ubiquitination is critical in regulating oncogenic pathways, the role of many ubiquitin-specific proteases (USPs) in NPC remains unexplored. In this study, we conducted a systematic screen of USPs to identify regulators of ULK1, a key initiator of autophagy and oncogene in NPC. We identified USP54 as a potent stabilizer of ULK1. Bioinformatic analyses of NPC transcriptomic datasets revealed that both ULK1 and USP54 are significantly overexpressed in NPC tissues. Functional assays demonstrated that USP54 overexpression enhanced NPC cell viability, colony formation, migration, and invasion by promoting autophagy, independently of PI3K/AKT pathway activity. Importantly, pharmacological inhibition of autophagy or genetic silencing of ULK1 abolished the oncogenic effects of USP54, indicating that ULK1-dependent autophagy mediates USP54-driven NPC progression. Our findings revealed that USP54 may promote autophagy and malignancy in NPC via regulating ULK1 stability, highlighting USP54 as a potential therapeutic target for NPC treatment.

Rosacea is a chronic inflammatory skin condition marked by excessive M1 macrophage polarization and angiogenesis, resulting in erythema and tissue inflammation. Despite available treatments, many patients experience recurrent flare-ups. This study explores chelerythrine, a bioactive component of Phellodendri Chinensis Cortex, for its therapeutic potential in rosacea through modulation of NF-κB, p38 MAPK, and STAT3 signaling, inflammation, and vascular regulation. Using an LL-37-induced rosacea-like mouse model, THP-1-derived M1 macrophages and human umbilical vein endothelial cells (HUVECs), chelerythrine's effects on macrophage polarization, cytokine expression, angiogenesis, and pathway activation of NF-κB, p38 MAPK, and STAT3 were evaluated. Chelerythrine significantly reduced epidermal thickness, inflammatory cell infiltration, and pro-inflammatory markers (TNF-α and IL-1β). It inhibited NF-κB, p38 MAPK, and STAT3 activation and decreased M1 polarization markers, shifting towards an anti-inflammatory profile. Furthermore, chelerythrine reduced vascular density and VEGF expression, impairing angiogenesis-related behaviors in HUVECs. These findings suggest that chelerythrine holds promise as a treatment for rosacea by mitigating inflammation and angiogenesis through targeted multiple pathways and macrophage modulation.

Acid extraction has been and remains one of the most widely used methods for preparing histones. Over the years, dilute hydrochloric or sulphuric acid solutions have been used alternately for histone extraction, followed by acetone or trichloroacetic acid precipitation, respectively. Although a sulphuric acid method has become commonplace in recent years, the protocol is quite involved and can pose problems when trying to solubilize the histones obtained this way. In this paper, we describe an alternative approach based on an early protocol using hydrochloric acid. The new method is technically straightforward and produces histones that are readily amenable to downstream uses, including sodium dodecyl sulfate, acetic acid-urea-Triton X-100, two-dimensional polyacrylamide gel electrophoresis, and mass spectrometry.

Abnormal lipid accumulation following myocardial infarction (MI) serves as a critical pathological factor contributing to cardiomyocyte injury. The nuclear receptor corepressor 1 (NCOR1) is famous as a key regulator in atherosclerosis, fatty liver, and other metabolic diseases, and recent evidence suggested that NCOR1 exerted a protective action in damaged heart cells. In this study, in a murine MI model induced by left anterior descending coronary artery ligation, we observed a significant downregulation of NCOR1 in myocardial tissues. NCOR1 was also downregulated in oxygen-glucose deprivation (OGD)-treated H9C2 cells, in which NCOR1 overexpression improved lipid metabolic dysregulation and peroxidation. Mechanistically, NCOR1 interacted with peroxisome proliferator activated receptor gamma (PPARγ) protein, which transcriptionally activated the expression of the mitophagy marker gene PINK1. Either knockdown of PPARγ or PINK1 was able to reverse the improvement of NCOR1 overexpression on OGD-induced dysregulation of mitophagy, lipid peroxidation, and cardiomyocyte damage. Finally, we demonstrated that NCOR overexpression (mediated by lentiviral vector) reduced infarct size, attenuated myocardial damage, and significantly improved cardiac function in MI mice. These findings not only identify NCOR1 as a novel protector in hypoxic-ischemic myocardium but also delineate the "NCOR1-PPARγ-PINK1" axis as a novel mechanism for improving mitochondrial function and lipid peroxidation, offering a promising therapeutic target for MI treatment.

Actinomycin D (Act D) was the first FDA-approved anticancer antibiotic. However, its widespread application was hindered by dose-limiting toxicities. In the current study, we investigated the in vitro and in vivo anticancer efficacy of the combination of Act D with resveratrol. We found that the combination of Act D and resveratrol has better in vitro efficacy than any of the single agent. We also explored the underlying mechanism by investigating the activation of the p53 pathway. Consistent with the cell growth inhibition, Act D, resveratrol, and their combination activated p53 and induced the expression of p21, PUMA, and GDF15 mRNA and proteins. The combination had better effects than any of the single agents alone. Ablation of p53 significantly protected cells and confirmed p53-dependent expression of these genes. Finally, we investigated the in vivo efficacy of these agents and their combination using xenograft model. Act D, resveratrol, and their combination significantly inhibited the growth of xenografts. The in vivo efficacy was further supported by Ki-67 expression in tumor tissues. Taken together, our findings demonstrated that although the combination of Act D and resveratrol showed better efficacy in vitro than any of the single agent, the in vivo efficacy was not improved.

Lactoferrin (Lf) is a multifunctional glycoprotein with antimicrobial, anti-inflammatory, and antioxidant properties that have been proposed as a therapeutic adjunct in wound healing. As keratinocytes are key drivers of re-epithelialization, this study investigated the effects of Lf on human keratinocyte cell line (HaCaT) cells with a focus on viability, proliferation, migration, and oxidative stress. HaCaT cells were treated with Lf at concentrations of 5, 7.5, and 10 µg/mL, and outcomes were assessed using metabolic and proliferation assays, a scratch wound healing assay, and measurements of nitrite, thiols, and antioxidant enzyme activities. Lf preserved keratinocyte viability and did not induce uncontrolled proliferation, indicating good cellular tolerance. Migration was not affected at early time-points but showed modest enhancement at 48 h in the 5 and 7.5 µg/mL groups. At the redox level, Lf selectively increased catalase activity across all doses, while nitrite and superoxide dismutase remained unchanged and thiols and glutathione S-transferase decreased at higher concentrations. Together, these findings identify Lf as a redox-centric modulator that enhances hydrogen peroxide detoxification without compromising cell integrity, supporting its potential as a safe adjunctive agent to promote orderly wound repair.

DFAT cells represent an attractive source of stem cells in tissue engineering and in the potential treatment of several clinical conditions. Our objective was to determine whether DFAT cells originate from mature adipocytes and address whether contamination from the stromal vascular fraction (SVF) could be as a source for these cells. A murine adiponectin-creERT;mT/mG model was used with the excision of the cassette induced by tamoxifen injection for the cells expressing adiponectin (adipoq). This model allows distinguishing of mature adipocytes (green fluorescence) from other SVF cell types (red fluorescence) based on the fluorescent protein expressed. Mature adipocytes and SVF cells were isolated from adipose tissues by collagenase digestion. Ceiling cultures were imaged by time-lapse microscopy. Confocal microscopy was used to follow cells over 21 days. Time-lapse microscopy experiments showed liposecretion occurring in mature adipocytes displaying green fluorescence. Confocal imaging allowed the identification of a heterogeneous cell population expressing green but also red fluorescence after 21 days of culture. Asymmetrical division of mature adipocytes was not observed. In conclusion, liposecretion of mature adipocytes is a phenomenon that can be observed in vitro and DFAT cells do originate from mature adipocytes. However, the population of DFAT cells is heterogenous.

This study aims to explore the role of 1-deoxynojirimycin (DNJ) in high glucose-induced β-cells and to further explore the molecular mechanism of DNJ effect on β-cells through network pharmacology. In the study, high glucose treatment of mouse INS-1 cells inhibited cell proliferation and insulin secretion, decreased the expression of Bcl-2 protein and Ins1 and Ins2 genes, promoted apoptosis, and increased cleaved caspase-3 and cleaved caspase-9 expression levels as well as intracellular reactive oxygen species production. DNJ treatment significantly restored the dysfunction of INS-1 cells induced by high glucose, and DNJ showed no toxicity to normal INS-1 cells. Silencing CEBPA promoted, while overexpression of CEBPA relieved the dysfunction of pancreatic β-cells induced by high glucose. DNJ treatment partially restored the pancreatic β-cell dysfunction caused by silencing CEBPA. In conclusion, DNJ can inhibit high glucose-induced pancreatic β-cell dysfunction by promoting the expression of CEBPA.