Protein profiling and functional analysis of liver mitochondria from rats with nonalcoholic steatohepatitis

Mg-ZIF nanozyme regulates the switch between osteogenic and lipogenic differentiation in BMSCs via lipid metabolism

The accumulation of reactive oxygen species (ROS) within the bone marrow microenvironment leads to diminished osteogenic differentiation and heightened lipogenic differentiation of mesenchymal stem cells residing in the bone marrow, ultimately playing a role in the development of osteoporosis (OP). Mitigating ROS levels is a promising approach to counteracting OP. In this study, a nanozyme composed of magnesium-based zeolitic imidazolate frameworks (Mg-ZIF) was engineered to effectively scavenge ROS and alleviate OP. The results of this study indicate that Mg-ZIF exhibits significant potential in scavenging ROS and effectively promoting osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Additionally, Mg-ZIF was found to inhibit the differentiation of BMSCs into adipose cells. In vivo experiments further confirmed the ability of Mg-ZIF to mitigate OP by reducing ROS levels. Mechanistically, Mg-ZIF enhances the differentiation of BMSCs into osteoblasts by upregulating lipid metabolic pathways through ROS scavenging. The results indicate that Mg-ZIF has potential as an effective therapeutic approach for the treatment of osteoporosis.

TMT Labeling Reveals the Effects of Exercises on the Proteomic Characteristics of the Subcutaneous Adipose Tissue of Growing High-Fat-Diet-Fed Rats

Aim: Growing period is an important period for fat remodeling. High-fat diet and exercise are reasons for adipose tissue (AT) remodeling, but existing evidence is not enough. Therefore, the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on the proteomic characteristics of the subcutaneous AT of growing rats on normal diet or high-fat diet (HFD) were determined. Methods: Four-week-old male Sprague-Dawley rats (n = 48) were subdivided into six groups: normal diet control group, normal diet-MICT group, normal diet-HIIT group, HFD control group, HFD-MICT group, and HFD-HIIT group. Rats in the training group ran on a treadmill 5 days a week for 8 weeks (MICT: 50 min at 60-70% VO_2max intensity; HIIT: 7 min of warm-up and recovery at 70% VO_2max intensity, 6 sets of 3 min of 30% VO_2max followed by 3 min 90% VO_2max). Following physical assessment, inguinal subcutaneous adipose tissue (sWAT) was collected for proteome analysis using tandem mass tag labeling. Results: MICT and HIIT attenuated body fat mass and lean body mass but did not affect weight gain. Proteomics revealed the impact of exercise on ribosome, spliceosome, and the pentose phosphate pathway. However, the effect was reversed on HFD and normal diet. The differentially expressed proteins (DEPs) affected by MICT were related to oxygen transport, ribosome, and spliceosome. In comparison, the DEPs affected by HIIT were related to oxygen transport, mitochondrial electron transport, and mitochondrion protein. In HFD, HIIT was more likely to cause changes in immune proteins than MICT. However, exercise did not seem to reverse the protein effects of HFD. Conclusion: The exercise stress response in the growing period was stronger but increased the energy metabolism and metabolism. MICT and HIIT can reduce fat, increase muscle percentage, and improve maximum oxygen uptake in rats fed with HFD. However, in rats with normal diet, MICT and HIIT triggered more immune responses of sWAT, especially HIIT. In addition, spliceosomes may be the key factors in AT remodeling triggered by exercise and diet.

Silibinin Promotes Cell Proliferation Through Facilitating G1/S Transitions by Activating Drp1-Mediated Mitochondrial Fission in Cells

Heart, liver, and kidney, which are known as the essential organs for metabolism, possess the unique ability to regulate the proliferation function of the body against injury. Silibinin (SB), a natural polyphenolic flavonoid extracted from traditional herb Silybum marianum L., has been used to protect hepatocytes. Whether SB can regulate mitochondrial fission in normal cells and the underlying mechanisms remain unclear. Here, we showed that SB markedly promoted cell proliferation by facilitating G1/S transition via activating dynamin-related protein 1 (Drp1), which in turn mediated mitochondrial fission in these normal cells. SB dose-dependently increased the mitochondrial mass, mtDNA copy number, cellular adenosine triphosphate production, mitochondrial membrane potential, and reactive oxygen species in normal cells. Furthermore, SB dose-dependently increased the expression of Drp1. Blocking Drp1 abolished SB-induced mitochondrial fission. In conclusion, we demonstrate that SB promotes cell proliferation through facilitating G1/S transition by activating Drp1-mediated mitochondrial fission. This study suggests that SB is a potentially useful herbal derivative for the daily prevention of various diseases caused by impaired mitochondrial fission.

Silibinin Induces G2/M Cell Cycle Arrest by Activating Drp1-Dependent Mitochondrial Fission in Cervical Cancer

Cervical cancer is the fourth leading cancer type and the second most common gynecological malignancy among women worldwide. Silibinin (SB), a chief bioactive natural polyphenolic flavonoid of Silybum marianum L., has been used clinically for its hepatocyte protective effects. It also has anticancer effects via the induction of apoptosis and cell cycle arrest. However, the effects of SB on cervical cancer cells through mitochondrial fission have not been studied. Here, we showed that SB markedly suppressed cervical cell proliferation by inducing G2/M cell cycle arrest via the activation of dynamin-related protein 1 (Drp1), which in turn mediated the mitochondrial fission dysfunction both in vitro and in vivo. SB decreased the ATP content, mitochondrial membrane potential, and mtDNA copy number, as well as reduced the reactive oxygen species levels in cervical cells. Furthermore, SB induced excessive mitochondrial fragmentation and reduced tubule formation. Further study showed that knockdown of Drp1 abolished the SB-induced G2/M cell cycle arrest in cervical cancer cells by inhibiting the mitochondrial fission pathway. More importantly, SB inhibited Hela cell growth in vivo model. In conclusion, we are the first to demonstrate that SB induces cervical cancer cell G2/M cell cycle arrest by activating Drp1-dependent mitochondrial fission dysfunction. This study suggests the strategy of inducing Drp1-dependent mitochondrial fission for cervical cancer prevention and treatment.

Proteomics approach to investigate dynamic protein profile involved in high fat diet-induced fatty liver disease in rats

Nonalcoholic fatty liver disease (NAFLD) is a disorder of the liver found worldwide. The molecular mechanisms underlying NAFLD initiation and progression, however, remain poorly understood. In this study, fluorescence difference gel electrophoresis (DIGE) combined with mass spectrometry was performed to profile the intracellular processes in the rat liver at the proteome level when rats were fed a high-fat diet for 8 weeks. Dynamic changes of 27 protein spots were observed. Among them, upregulation of 14 spots and downregulation of 13 spots were observed during the eight weeks of the high fat diet-induction period. These spots were analyzed by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF), and ultimately 24 proteins were identified with more than 95% confidence. Gene ontology (GO) annotation indicated that these proteins were implicated in the metabolism of carbohydrates, lipids, and amino acids. Four proteins were validated by western blot. Further functional studies on these dynamically changing proteins may lead to a better understanding of the mechanisms of high fat diet-induced fatty liver disease.