Rab2A regulates the progression of nonalcoholic fatty liver disease downstream of AMPK-TBC1D1 axis by stabilizing PPARγ.

Nonalcoholic fatty liver disease (NAFLD) affects approximately a quarter of the population worldwide, and persistent overnutrition is one of the major causes. However, the underlying molecular basis has not been fully elucidated, and no specific drug has been approved for this disease. Here, we identify a regulatory mechanism that reveals a novel function of Rab2A in the progression of NAFLD based on energy status and PPARγ. The mechanistic analysis shows that nutrition repletion suppresses the phosphorylation of AMPK-TBC1D1 signaling, augments the level of GTP-bound Rab2A, and then increases the protein stability of PPARγ, which ultimately promotes the hepatic accumulation of lipids in vitro and in vivo. Furthermore, we found that blocking the AMPK-TBC1D1 pathway in TBC1D1S231A-knock-in (KI) mice led to a markedly increased GTP-bound Rab2A and subsequent fatty liver in aged mice. Our studies also showed that inhibition of Rab2A expression alleviated hepatic lipid deposition in western diet-induced obesity (DIO) mice by reducing the protein level of PPARγ and the expression of PPARγ target genes. Our findings not only reveal a new molecular mechanism regulating the progression of NAFLD during persistent overnutrition but also have potential implications for drug discovery to combat this disease.

Trajectory-dependent threshold effects of proton stopping power in LiF nanosheets.

We conducted a study on the trajectory-dependent threshold effects of proton stopping power in LiF nanosheets using time-dependent density functional theory non-adiabatically coupled to the molecular dynamics. This study covered protons with initial velocities in the range of 0.1-1.0 a.u., offering a vast amount of detailed information on the electronic structure during the stopping process with superior spatial and temporal resolution. Our results show that the impact parameters of incident protons play a crucial role in determining the threshold behavior of proton stopping power in LiF nanosheets. Most importantly, we found that close collisions do not exhibit a discernible threshold. In addition, the research results also revealed the time dependence of the number of electrons occupying the atomic orbitals of F and Li as protons pass through the nanosheets.

Effects of semicore electrons on stopping power in helium-irradiated aluminum nanosheets.

The stopping power of energetic He ions traversing an Al film is studied by combining the time-dependent density-functional theory method with molecular dynamics simulations. We investigated the dependence of the semicore electron excitation of the Al film on the projectile's trajectory and its charge state. Our results show that for the off-channeling trajectories the semicore electrons contribute significantly to the stopping power of the Al film as the He+ ion velocity exceeds 1.0 a.u, and in contrast, it is negligible for the channeling trajectories. Most importantly, we found two unexpected effects of semicore electrons on the stopping power in helium-irradiated aluminum nanosheets, i.e., (1) the semicore electrons can contribute to the energy loss for both high and low energy projectiles under the off-channeling trajectory; (2) as the projectile velocity increases from 0.4 a.u. to 2.0 a.u. although semicore electron excitation (including transition in the target, ionization away from the target and transfer to the projectile ion) of the target atom is gradually inhibited, the influence of semicore electrons on valence electron excitation is gradually enhanced. Our finding allows us to gain new insights into the stopping of ions in metals.

Aculebiphenyl A-B, new biphenyl derivatives from Ruscus aculeatus.

The investigation of chemical constituents from the rhizomes of Ruscus aculeatus resulted in the isolation of two new biphenyl derivatives, aculebiphenyls A and B (1-2), together with two known analogs (3-4). Their chemical structures were elucidated based on extensive spectroscopic interpretation and HR-ESI-MS analysis. Compounds 3-4 were isolated from the Ruscus genus for the first time. The isolated compounds were tested for anti-inflammatory activities and antibacterial activities. Compound 1 exhibited significant inhibitory effects on LPS-induced NO production and COX-2 with IC50 values of 10.8 µM and 0.4 µM. Compound 1 also significantly down-regulated the levels of inflammatory cytokines IL-1ß, IL-6, and TNF-α. Compound 1 showed moderate antibacterial activities.

Elucidating the effects of arginine and lysine on a monoclonal antibody C-terminal lysine variation in CHO cell cultures.

C-terminal lysine variants are commonly observed in monoclonal antibodies (mAbs) and found sensitive to process conditions, especially specific components in culture medium. The potential roles of media arginine (Arg) and lysine (Lys) in mAb heavy chain C-terminal lysine processing were investigated by monitoring the lysine variant levels under various Arg and Lys concentrations. Both Arg and Lys were found to significantly affect lysine variant level. Specifically, lysine variant level increased from 18.7 to 31.8 % when Arg and Lys concentrations were increased from 2 to 10 mM. Since heterogeneity of C-terminal lysine residues is due to the varying degree of proteolysis by basic carboxypeptidases (Cps), enzyme (basic Cps) level, pH conditions, and product (Arg and Lys) inhibition, which potentially affect the enzymatic reaction, were investigated under various Arg and Lys conditions. Enzyme level and pH conditions were found not to account for the different lysine variant levels, which was evident from the minimal variation in transcription level and intracellular pH. On the other hand, product inhibition effect of Arg and Lys on basic Cps was evident from the notable intracellular and extracellular Arg and Lys concentrations comparable with Ki values (inhibition constant) of basic Cps and further confirmed by cell-free assays. Additionally, a kinetic study of lysine variant level during the cell culture process enabled further characterization of the C-terminal lysine processing.

Culture temperature modulates monoclonal antibody charge variation distribution in Chinese hamster ovary cell cultures.

OBJECTIVE: To investigate the effect of lowering culture temperature on monoclonal antibody charge variation distribution in Chinese hamster ovary cell cultures. RESULTS: In both batch and fed-batch cultures, lowering the culture temperature decreased the antibody acidic variant levels. The acidic variant levels (defined as variants eluting earlier than the main peak of an antibody during HPLC) at 32 °C were about 10 % lower than those at 37 °C at the end of both batch and fed-batch cultures. Additionally, lowering the culture temperature increased the lysine variant level, which further increased basic variant level. The lysine variant levels at 32 °C were about 8 % (batch culture) and 3 % (fed-batch culture) higher than those at 37 °C at the end of cultures. Real-time PCR results suggests that the decrease in carboxypeptidase B transcription level might be partially responsible for the increased lysine variant level at sub-physiological temperatures. CONCLUSION: Culture temperature exhibits noticeable impact on antibody charge variation distribution, especially the acidic variants and lysine variants.

Correlation between CDK1 protein and CDK1 mRNA during oocyte maturation in mouse.

The aim of this study was to investigate the correlation between CDK1 protein and CDK1 mRNA during oocyte maturation in vivo in mouse. GV, GVBD, MI and MII oocytes were obtained from mice, respectively. Western blot validated that the CDK1 protein expression increased continuously and significantly with oocyte maturation in vivo (P<0.05). Real-time qRT-PCR showed that CDK1 mRNA expression was down-regulated significantly during transformation from GV to MI stages (P<0.05), and up-regulated significantly during transformation from MI to MII stages (P<0.05). The level of CDK1 mRNA peaked at MII stages. Spearman correlation analysis indicated that CDK1 protein expression was poor correlation with CDK1 mRNA expression during oocyte maturation in vivo (R=0.200). This finding suggested that the increase of CDK1 protein during oocyte maturation in vivo was not entirely caused by the change of transcription level. The results provide new food for thought for further research on the molecular mechanism of oocyte maturation in vivo.

Self-Assembled Supramolecular Micelles with pH-Responsive Properties for More Effective Cancer Chemotherapy.

pH-Responsive hydrogen-bonded supramolecular micelles, composed of a water-soluble poly(ethylene glycol) polymer with two terminal sextuple hydrogen bonding groups, can spontaneously organize in aqueous media to give well-defined, uniformly sized spherical micelles. The supramolecular micelles exhibit a number of unique physical characteristics, such as interesting amphiphilic behavior, desirable micellar size and nanospherical morphology, excellent biocompatibility, tailorable drug-loading capacities, and high structural stability in media containing serum or red blood cells. In addition, the drug release kinetics of drug-loaded micelles can be easily manipulated to achieve the desired release profile by regulating the environmental pH, thus these micelles are highly attractive candidates as an intelligent drug carrier system for cancer therapy. Cytotoxicity assays showed that the drug-loaded micelles induced pH-dependent intracellular drug release and exerted strong antiproliferative and cytotoxic activities toward cancer cells. Importantly, cellular uptake and flow cytometric analyses confirmed that a mildly acidic intracellular environment significantly increased cellular internalization of the drug-loaded micelles and subsequent drug release in the cytoplasm and nucleus of cancer cells, resulting in more effective induction of apoptotic cell death. Thus, this system may provide an efficient route toward achieving the fundamental properties and practical realization of pH-sensitive drug-delivery systems for chemotherapy.

Entrapment of an adenine derivative by a photo-irradiated uracil-functionalized micelle confers controlled self-assembly behavior.

HYPOTHESIS: Invoking cooperative assembly of the uracil-functionalized supramolecular polymer BU-PPG [uracil end-capped poly(propylene glycol)] upon association with the nucleobase adenine derivative A-MA [methyl 3-(6-amino-9H-purin-9-yl)propanoate] as a model drug provides a new concept to control and tune the properties of supramolecular complexes and holds significant potential for the development of safer, more effective drug delivery systems. EXPERIMENTS: BU-PPG and A-MA were successfully developed and exhibited specific recognition and high affinity, which enabled reversible complementary adenine-uracil (A-U) hydrogen bonding-induced formation of spherical micelles in aqueous solution. The self-assembly and controllable A-MA release behavior of BU-PPG/A-MA micelles were studied using morphological analysis and optical and light scattering techniques to investigate the effect of photoirradiation and temperature on the complementary hydrogen bond interactions between BU-PPG and A-MA. FINDINGS: The resulting micelles possess unusual physical properties, including controlled photoreactivity kinetics, controllable self-assembled morphology and low cytotoxicity in vitro, as well as reversible temperature-responsive behavior. Importantly, irradiated micelles exhibited excellent long-term structural stability under normal physiological conditions and serum disturbance. Increasing the temperature triggered rapid release of A-MA by disrupting A-U complexes. These findings represent an entirely new, promising strategy for the development of multi-controlled release drug delivery nanocarriers based on complementary hydrogen bonding interactions.

Xanthones from Garcinia paucinervis with in vitro anti-proliferative activity against HL-60 cells.

Three new xanthones, paucinervins H-J (1-3), as well as eleven known compounds (4-14), were isolated from the leaves of Garcinia paucinervis. The structures of the new compounds (1-3) were elucidated by 1D, 2D NMR spectra and HR ESIMS. In vitro antiproliferative activity against human promyelocytic leukemia HL-60 cells was tested, among which, compounds 2, 5, 6 and 7 exhibited strong growth inhibitory effects with GI50 values ranging from 1.30 to 9.08 µM, respectively. Preliminary SARs were also discussed.

Quinolone and indole alkaloids from the fruits of Euodia rutaecarpa and their cytotoxicity against two human cancer cell lines.

Four quinolone alkaloids (1-4) and three indole alkaloids (20-22), together with 30 known alkaloids (5-19, 23-37), were isolated from the fruits of Euodia rutaecarpa. Their structures were established by spectroscopic analyses. The in vitro cytotoxic activities of these alkaloids against leukaemia HL-60 and prostate cancer PC-3 cell lines were evaluated.

Effect of simvastatin on expression of IL17, HMGB1 and TLR4 in LN kidney tissues of rats.

OBJECTIVES: To observe the intervention influence and effect of simvastatin on the expression of interleukin 17 (LI17), high mobility group protein 1 (HMGB1) and TLR4 path in Lupus nephritis (LN) rats. METHODS: A total of 28 BSXSB male mice with LN (16 weeks) were randomly divided into observation group and the comparison group, observation group was given 6 mg•kg(-1)•d(-1) simvastatin in 0.1% PBS lavage for 4 weeks, the comparison group was not given any treatment. Blood urea nitrogen (BUN) level and urine trace albumin (Scr) level of two groups were determined. The expression of IL17, HMGB1 and TLR4 protein was detected using immune histochemical method, and the kidney histological damage was observed. RESULTS: BNU, LI17, HMGB1, TLR4 protein and HMGB1 mRNA in observation group was significantly lower than that in control group (P<0.05); There was no statistical difference of Scr level between two groups (P>0.05). Histological observation showed glomerular lesions integral of observation group was obviously lower than that of control group. CONCLUSIONS: Simvastatin can reduce the expression of IL17, HMGB1 and TLR4 protein in LN mice, thereby can inhibit the autoimmune response as a potential treatment function of LN.

An investigation into the relationship between metabolic responses and energy regulation in antibody-producing cell.

Energy-efficient metabolic responses were often noted in high-productive cultures. To better understand these metabolic responses, an investigation into the relationship between metabolic responses and energy regulation was conducted via a comparative analysis among cultures with different energy source supplies. Both glycolysis and glutaminolysis were studied through the kinetic analyses of major extracellular metabolites concerning the fast and slow cell growth stages, respectively, as well as the time-course profiles of intracellular metabolites. In three cultures showing distinct antibody productivities, the amino acid metabolism and energy state were further examined. Both the transition of lactate from production to consumption and steady intracellular pools of pyruvate and lactate were observed to be correlated with efficient energy regulation. In addition, an efficient utilization of amino acids as the replenishment for the TCA cycle was also found in the cultures with upregulated energy metabolism. It was further revealed that the inefficient energy regulation would cause low cell productivity based on the comparative analysis of cell growth and productivity in cultures having distinct energy regulation.