Cholesterol myristate suppresses the apoptosis of mesenchymal stem cells via upregulation of inhibitor of differentiation

Film-forming polymer solutions containing cholesterol myristate and berberine mediate pressure ulcer repair via the Wnt/β-catenin pathway

Pressure ulcer (PU) is a worldwide problem that is difficult to address because of the related inflammatory response, local hypoxia, and repeated ischaemia/reperfusion, causing great suffering and financial burden to patients. Traditional Chinese medicine turtle plate powder can treat skin trauma, but its composition is complex and inconvenient to use. Here, we combined cholesterol myristate (S8) with berberine (BBR), with anti-inflammatory and antibacterial effects, as a drug and used hydroxypropyl methylcellulose and polyvinylpyrrolidone K30 as carriers to construct a novel film-forming polymeric solution (S8 + BBR FFPS), comprehensively study its reparative effect on PU and explore the potential mechanism in rat PU models. The results showed that S8 + BBR FFPS inhibits excessive inflammatory response, promotes re-epithelialization, and promotes hair follicle growth during the healing process of PU, which may be related to the activation of the Wnt/β-catenin signalling pathway by S8 + BBR FFPS to mediate hair follicle stem cell proliferation and maintain skin homeostasis. Therefore, S8 + BBR FFPS may be a potential candidate for the treatment of chronic skin injury, and its association with the Wnt/β-catenin signalling pathway may provide new ideas to guide the design of biomaterial-based wound dressings for chronic wound repair.

Novel chemical contaminants associated with thirdhand smoke in settled house dust

Thirdhand smoke (THS) is the persistent and toxic residue from tobacco smoke in indoor environments. A comprehensive understanding of the chemical constituents of THS is necessary to assess the risks of long-term exposure and to establish reliable THS tracers. The objective of this study was to investigate compounds associated with THS through nontargeted analysis (NTA) of settled house dust samples from smokers' and non-smokers' homes, using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS). Compounds that were either only present in dust from smokers' homes or that had significantly larger abundance than in non-smokers' homes were termed qualified compounds. We identified 140 qualified compounds, and of these, 42 compounds were tentatively identified by searching matching mass spectra in NIST electron impact (EI) mass spectral library including 20 compounds confirmed with their authentic standards. Among the 42 compounds, 26 compounds were statistically more abundant (p < 0.10) in dust from homes of smokers; seven were tobacco-specific compounds, two of which (nornicotyrine, 3-ethenylpyridine) have not been reported before in house dust. Two compounds, tris (2-chloroethyl) phosphate (a toxic compound used as a flame retardant and reported in tobacco) and propanoic acid, 2-methyl-, 1-(1,1-dimethylethyl)-2-methyl-1,3-propanediyl ester (highly abundant and reported in exhaled air of smokers), were found in dust from all smokers' homes and in zero non-smokers' homes, making these potential THS tracers, possibly associated with recent smoking. Benzyl methyl ketone was significantly higher in dust in smokers' homes, and was previously reported not as a product of tobacco but rather as a form of methamphetamine. This compound was recently reported in mainstream tobacco smoke condensate through NTA as well. These identified potential tracers and chemical components of THS in this study can be further investigated for use in developing THS contamination and exposure assessments.

Systems biology approach to exploring the effect of cyclic stretching on cardiac cell physiology

Although mechanical forces are involved in pressure-overloaded cardiomyopathy, their effects on gene transcription profiles are not fully understood. Here, we used next-generation sequencing (NGS) to investigate changes in genomic profiles after cyclic mechanical stretching of human cardiomyocytes. We found that 85, 87, 32, 29, and 28 genes were differentially expressed after 1, 4, 12, 24, and 48 hours of stretching. Furthermore, 10 of the 29 genes that were up-regulated and 11 of the 28 that were down-regulated after 24 h showed the same changes after 48 h. We then examined expression of the genes that encode serpin family E member 1 (SERPINE1), DNA-binding protein inhibitor 1 (ID1), DNA-binding protein inhibitor 3 (ID3), and CCL2, a cytokine that acts as chemotactic factor in monocytes, in an RT-PCR experiment. The same changes were observed for all four genes after all cyclic stretching durations, confirming the NGS results. Taken together, these findings suggest that cyclical stretching can alter cardiac cell physiology by activating cardiac cell metabolism and impacting cholesterol biosynthesis signaling.

(+)-Cholesten-3-one induces osteogenic differentiation of bone marrow mesenchymal stem cells by activating vitamin D receptor

In our previous reports, it was revealed that steroids in traditional Chinese medicine (TCM) have the therapeutic potential to treat bone disease. In the present study, an in vitro model of a vitamin D receptor response element (VDRE) reporter gene assay in mesenchymal stem cells (MSCs) was used to identify steroids that enhanced osteogenic differentiation of MSCs. (+)-cholesten-3-one (CN), which possesses a ketone group that is modified in cholesterol and cholesterol myristate, effectively promoted the activity of the VDRE promoter. Phenotypic cellular analysis indicated that CN induced differentiation of MSCs into osteogenic cells and increased expression of specific osteogenesis markers, including alkaline phosphatase, collagen II and Runt-related transcription factor 2. Furthermore, CN significantly increased the expression of osteopontin, the target of the vitamin D receptor (VDR), which indicated that CN may activate vitamin D receptor signaling. Over-expression of VDR or knockdown studies with VDR-small interfering RNA revealed that the pro-differentiation effects induced by CN required VDR. Furthermore, the present study determined that the C-terminal region of the VDR is responsible for the action of CN. Taken together, the present findings demonstrated that CN induced osteogenic differentiation of MSCs by activating VDR. The present study explored the regulation of stem cells by using a series of similar steroids and provided evidence to support a potential strategy for the screening of novel drugs to treat bone disease in the future.

Cholesterol Retards Senescence in Bone Marrow Mesenchymal Stem Cells by Modulating Autophagy and ROS/p53/p21Cip1/Waf1 Pathway

In the present study, we demonstrated that bone marrow mesenchymal stem cells (BMSCs) of the 3rd passage displayed the senescence-associated phenotypes characterized with increased activity of SA-β-gal, altered autophagy, and increased G1 cell cycle arrest, ROS production, and expression of p53 and p21^Cip1/Waf1 compared with BMSCs of the 1st passage. Cholesterol (CH) reduced the number of SA-β-gal positive cells in a dose-dependent manner in aging BMSCs induced by H₂O₂ and the 3rd passage BMSCs. Moreover, CH inhibited the production of ROS and expression of p53 and p21^Cip1/Waf1 in both cellular senescence models and decreased the percentage of BMSCs in G1 cell cycle in the 3rd passage BMSCs. CH prevented the increase in SA-β-gal positive cells induced by RITA (reactivation of p53 and induction of tumor cell apoptosis, a p53 activator) or 3-MA (3-methyladenine, an autophagy inhibitor). Our results indicate that CH not only is a structural component of cell membrane but also functionally contributes to regulating cellular senescence by modulating cell cycle, autophagy, and the ROS/p53/p21^Cip1/Waf1 signaling pathway.

Cholesterol suppresses adipocytic differentiation of mouse adipose-derived stromal cells via PPARγ2 signaling

The effects of cholesterol on cell proliferation and adipocytic differentiation have been evaluated for the first time in mouse adipose-derived stromal cells (mASCs). Cholesterol loading by using cholesterol:methyl- β-cyclodextrin (Chol:MβCD) complexes promoted cellular levels of free cholesterol (FC) and cholesteryl ester (CE), induced high cell proliferation of mASCs dose-dependently. Compared with control cells, cholesterol-treated mASCs showed an impaired differentiation process in both dose- and time-dependent manners, based on reduced oil red O-stained lipid droplets, SREBP-1, PPARγ2 and aP2 expression levels. The involvement of SREBP-1-mediated PPARγ2 in the effects of cholesterol on mASC adipogenesis was elucidated. These results point to cholesterol as a modulator of adipogenesis, which separate cholesterol itself from other components of modified lipoproteins.