High-Resolution Intact Protein Analysis via Phase-Modulated, Stepwise Frequency Scan Ion Trap Mass Spectrometry.

Mass spectrometry (MS) using an electron multiplier for intact protein analysis remains limited. Because of the massive size and complex structure of proteins, the slow flight speed of their ions results in few secondary electrons and thus low detection sensitivity and poor spectral resolution. Thus, we present a compact ion trap-mass spectrometry approach to directly detect ion packets and obtain the high-resolution molecular signature of proteins. The disturbances causing deviations of ion motion and mass conversion have been clarified in advance. The radio frequency waveform used to manipulate ions is proposed to be a sequence of constant-frequency steps, interconnected by short time-outs, resulting in least dispersive distortion. Furthermore, more such constant-phase conjunctions are arranged in each step to compensate for fluctuations resulting from defects in the system and operation. In addition, two auxiliary pulses are generated in the right phase of each step to select ions of a specific secular state to detect one clean and sharp spectral line.This study demonstrates a top-down approach for the MS measurement of cytochrome C molecules, resulting in a spectral profile of the protein in its natural state at a resolution of 20 Da. Additionally, quick MS scans of other proteins were performed.

Evaluation of Articular Cartilage Regeneration Properties of Decellularized Cartilage Powder/Modified Hyaluronic Acid Hydrogel Scaffolds.

The articular cartilage has poor intrinsic healing potential, hence, imposing a great challenge for articular cartilage regeneration in osteoarthritis. Tissue regeneration by scaffolds and bioactive materials has provided a healing potential for degenerated cartilage. In this study, decellularized cartilage powder (DCP) and hyaluronic acid hydrogel modified by aldehyde groups and methacrylate (AHAMA) were fabricated and evaluated in vitro for efficacy in articular cartilage regeneration. In vitro tests such as cell proliferation, cell viability, and cell migration showed that DCP/AHAMA has negligible cytotoxic effects. Furthermore, it could provide an enhanced microenvironment for infrapatellar fat pad stem cells (IFPSCs). Mechanical property tests of DCP/AHAMA showed suitable adhesive and compressive strength. IFPSCs under three-dimensional (3D) culture in DCP/AMAHA were used to assess their ability to proliferate and differentiate into chondrocytes using normal and chondroinductive media. Results exhibited increased gene expression of COL2 and ACN and decreased COL1 expression. DCP/AHAMA provides a microenvironment that recapitulates the biomechanical properties of the native cartilage, promotes chondrogenic differentiation, blocks hypertrophy, and demonstrates applicability for cartilage tissue engineering and the potential for clinical biomedical applications.

Influence of Spin Coating and Dip Coating with Gelatin/Hydroxyapatite for Bioresorbable Mg Alloy Orthopedic Implants: In Vitro and In Vivo Studies.

Suitable biomechanical properties, good biocompatibility, and osteoconductivity of a degradable magnesium (Mg) alloy make it a potential material for orthopedic implants. The main limitation of Mg is its high corrosion rate in the human body. Surface modification is necessary to improve the Mg corrosion resistance. In this work, a polymeric layer of gelatin/nanohydroxyapatite (Gel/nHA) was coated on a ZK60 Mg alloy by dip coating and spin coating to test the corrosion resistance and biocompatibility in vitro and in vivo. The results from the in vitro test revealed that the coated groups reduced the corrosion rate with the corrosion current density by 59 and 81%, from 31.22 to 12.83 µA/cm2 and 5.83 µA/cm2 in the spin coating and dip coating groups, respectively. The dip coating group showed better corrosion resistance than the spin coating group with the lowest released hydrogen content (17.5 mL) and lowest pH value (8.23) and reducing the current density by 45%. In vitro, the relative growth rate was over 75% in all groups tested with MG63, demonstrating that the Mg substrate and coating materials were within the safety range. The dip coating and spin coating groups enhanced the cell proliferation with significantly higher OD values (3.3, 3.0, and 2.5, respectively) and had better antihemolysis and antiplatelet adhesion abilities than the uncoated group. The two coating methods showed no difference in the cellular response, cell migration, hemolysis, and platelet adhesion test. In in vivo tests in rats, the dip coating group also showed a higher corrosion resistance with a lower corrosion rate and mass loss than the spin coating group. In addition, the blood biochemistry and histopathology results indicated that all materials used in this study were biocompatible with living subjects. The present research confirmed that the two methods have no noticeable difference in cell and organ response but the corrosion resistance of dip coating was higher than that of spin coating either in vitro or in vivo.

IL-29 promoted obesity-induced inflammation and insulin resistance.

Adipocyte-macrophage crosstalk plays a critical role to regulate adipose tissue microenvironment and cause chronic inflammation in the pathogenesis of obesity. Interleukin-29 (IL-29), a member of type 3 interferon family, plays a role in host defenses against microbes, however, little is known about its role in metabolic disorders. We explored the function of IL-29 in the pathogenesis of obesity-induced inflammation and insulin resistance. We found that serum IL-29 level was significantly higher in obese patients. IL-29 upregulated IL-1ß, IL-8, and monocyte chemoattractant protein-1 (MCP-1) expression and decreased glucose uptake and insulin sensitivity in human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes through reducing glucose transporter 4 (GLUT4) and AKT signals. In addition, IL-29 promoted monocyte/macrophage migration. Inhibition of IL-29 could reduce inflammatory cytokine production in macrophage-adipocyte coculture system, which mimic an obese microenvironment. In vivo, IL-29 reduced insulin sensitivity and increased the number of peritoneal macrophages in high-fat diet (HFD)-induced obese mice. IL-29 increased M1/M2 macrophage ratio and enhanced MCP-1 expression in adipose tissues of HFD mice. Therefore, we have identified a critical role of IL-29 in obesity-induced inflammation and insulin resistance, and we conclude that IL-29 may be a novel candidate target for treating obesity and insulin resistance in patients with metabolic disorders.