Myeloid peroxisome proliferator-activated receptor α deficiency accelerates liver regeneration via IL-6/STAT3 pathway after 2/3 partial hepatectomy in mice.

Background: Liver regeneration is a fundamental process for sustained body homeostasis and liver function recovery after injury. Emerging evidence demonstrates that myeloid cells play a critical role in liver regeneration by secreting cytokines and growth factors. Peroxisome proliferator-activated receptor α (PPARα), the target of clinical lipid-lowering fibrate drugs, regulates cell metabolism, proliferation, and survival. However, the role of myeloid PPARα in partial hepatectomy (PHx)-induced liver regeneration remains unknown. Methods: Myeloid-specific PPARa-deficient (Ppara Mye-/-) mice and the littermate controls (Ppara fl/fl) were subjected to sham or 2/3 PHx to induce liver regeneration. Hepatocyte proliferation and mitosis were assessed by immunohistochemical (IHC) staining for 5-bromo-2'-deoxyuridine (BrdU) and Ki67 as well as hematoxylin and eosin (H&E) staining. Macrophage and neutrophil infiltration into livers were reflected by IHC staining for galectin-3 and myeloperoxidase (MPO) as well as flow cytometry analysis. Macrophage migration ability was evaluated by transwell assay. The mRNA levels for cell cycle or inflammation-related genes were measured by quantitative real-time RT-PCR (qPCR). The protein levels of cell proliferation related protein and phosphorylated signal transducer and activator of transcription 3 (STAT3) were detected by Western blotting. Results: Ppara Mye-/- mice showed enhanced hepatocyte proliferation and mitosis at 32 h after PHx compared with Ppara fl/fl mice, which was consistent with increased proliferating cell nuclear antigen (Pcna) mRNA and cyclinD1 (CYCD1) protein levels in Ppara Mye-/- mice at 32 h after PHx, indicating an accelerated liver regeneration in Ppara Mye-/- mice. IHC staining showed that macrophages and neutrophils were increased in Ppara Mye-/- liver at 32 h after PHx. Livers of Ppara Mye-/- mice also showed an enhanced infiltration of M1 macrophages at 32 h after PHx. In vitro, Ppara-deficient bone marrow-derived macrophages (BMDMs) exhibited markedly enhanced migratory capacity and upregulated M1 genes Il6 and Tnfa but downregulated M2 gene Arg1 expressions. Furthermore, the phosphorylation of STAT3, a key transcript factor mediating IL6-promoted hepatocyte survival and proliferation, was reinforced in the liver of Ppara Mye-/- mice after PHx. Conclusions: This study provides evidence that myeloid PPARα deficiency accelerates PHx-induced liver regeneration via macrophage polarization and consequent IL-6/STAT3 activation, thus providing a potential target for manipulating liver regeneration.

The role of hypoxia-inducible factors in cardiovascular diseases.

Cardiovascular diseases are the leading cause of death worldwide. During the development of cardiovascular diseases, hypoxia plays a crucial role. Hypoxia-inducible factors (HIFs) are the key transcription factors for adaptive hypoxic responses, which orchestrate the transcription of numerous genes involved in angiogenesis, erythropoiesis, glycolytic metabolism, inflammation, and so on. Recent studies have dissected the precise role of cell-specific HIFs in the pathogenesis of hypertension, atherosclerosis, aortic aneurysms, pulmonary arterial hypertension, and heart failure using tissue-specific HIF-knockout or -overexpressing animal models. More importantly, several compounds developed as HIF inhibitors or activators have been in clinical trials for the treatment of renal cancer or anemia; however, little is known on the therapeutic potential of these inhibitors for cardiovascular diseases. The purpose of this review is to summarize the recent advances on HIFs in the pathogenesis and pathophysiology of cardiovascular diseases and to provide evidence of potential clinical therapeutic targets.

Deficiency of peroxisome proliferator-activated receptor α attenuates apoptosis and promotes migration of vascular smooth muscle cells.

Peroxisome proliferator-activated receptor (PPAR) α is widely expressed in the vasculature and has pleiotropic and lipid-lowering independent effects, but its role in the growth and function of vascular smooth muscle cells (VSMCs) during vascular pathophysiology is still unclear. Herein, VSMC-specific PPARα-deficient mice (Ppara ΔSMC) were generated by Cre-LoxP site-specific recombinase technology and VSMCs were isolated from mice aorta. PPARα deficiency attenuated VSMC apoptosis induced by angiotensin (Ang) II and hydrogen peroxide, and increased the migration of Ang II-challenged cells.

Temporin-Like Peptides Show Antimicrobial and Anti-Biofilm Activities against Streptococcus mutans with Reduced Hemolysis.

In our previous study, temporin-GHaR (GHaR) showed potent antimicrobial activity with strong hemolytic toxicity. To overcome its weakness, we designed GHaR6R, GHaR7R, GHaR8R, GHaR9R, and GHaR9W by changing the number of positive charges and the hydrophobic surface of GHaR. With the exception of GHaR7R, the hemolytic toxicity of the derived peptides had been reduced, and the antimicrobial activities remained close to the parent peptide (except for GHaR9R). GHaR6R, GHaR7R, GHaR8R, and GHaR9W exhibited a great bactericidal effect on Streptococcus mutans (S. mutans), which is one of the main pathogens causing dental caries. According to the membrane permeation and scanning electron microscope (SEM) analysis, these derived peptides targeted to the cell membranes of planktonic bacteria, contributing to the disruption of the membrane integrity and leakage of the intracellular contents. Moreover, they inhibited the formation of biofilms and eradicated the mature biofilms of S. mutans. Compared with GHaR7R, the derived peptides showed less cytotoxicity to human oral epithelial cells (HOECs). The derived peptides are expected to be the molecular templates for designing antibacterial agents to prevent dental caries.

Synthesis of sheet-like polypyrrole nanowires for the microextraction of trace residues of pyrethroid pesticides in human plasma and molecular dynamics-aided study of adsorption mechanism.

The synthesized sheet-like polypyrrole (ppy) nanowires were used as solid phase extraction materials, followed by gas chromatography-mass spectrometry (GC-MS) for the detection of traces residues of pyrethroid pesticides in human plasma. A multiresidue method was developed and verified for the determination of trace pyrethroid residues (transfluthrin, allethrin, resmethrin, fenpropathrin, etofenprox, fenvalerate) in human plasma. In this study, using the cationic surfactant cetyltrimethylammonium bromide (CTAB) as a soft template, ppy nanowires with regular morphology were prepared by oxidative polymerization. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and other techniques were employed for characterization. Molecular dynamics analyses were used to simulate the adsorption mechanism of each pyrethroid and ppy nanowires. Based on density analysis, molecular recognition analysis, and binding energy, the van der Waals force was considered as an important driving force for the adsorption of pyrethroids and ppy nanowires. The limits of detection (LOD) of six pyrethroids were 0.008-0051 ng mL-1, and the limits of quantification (LOQ) were 0.028-0.162 ng mL-1. The relative standard deviations of ppy nanowires were 2.12-5.09%, and the recoveries of six pyrethroids ranged from 76.9 to 110.4%. The enrichment factors were within the range of 47.09-51.30. The experimental results showed that the method could be an efficient detection method for trace residue analysis of pyrethroid pesticides in complex biological samples. It would be advantageous for clinical monitoring and toxicological studies of pyrethroids.

Amino Acid Profiling Study of Psidium guajava L. Leaves as an Effective Treatment for Type 2 Diabetic Rats.

Type 2 diabetes mellitus (T2DM) has become a major disease threatening human health worldwide. At present, the treatment of T2DM cannot cure diabetes and is prone to many side effects. Psidium guajava L. leaves have been reported to possess hypoglycemic activity, and they have been widely used in diabetes treatment in the folk. However, the antidiabetic mechanism has not been clearly explained. Also, the change in amino acid profile can reflect a metabolic disorder and provide insights into system-wide changes in response to physiological challenges or disease processes. The study found that P. guajava L. leaves can decrease fasting blood glucose and lipid levels in type 2 diabetic rats induced by streptozotocin. Through the analysis of amino acid profiling following 20 days of gavage administration, the concentration data were modeled by principal component analysis and orthogonal partial least squares discriminant analysis to find the different metabolites and related metabolic pathways (including cysteine and methionine metabolism, valine, leucine, and isoleucine biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis) for the explanation of the hypoglycemic mechanism of P. guajava L., which provides an experimental and theoretical basis for diabetes prediction and for the development of new drugs for the treatment of diabetes.

Hypoxia inducible factor 1α in vascular smooth muscle cells promotes angiotensin II-induced vascular remodeling via activation of CCL7-mediated macrophage recruitment.

The process of vascular remodeling is associated with increased hypoxia. However, the contribution of hypoxia-inducible factor 1α (HIF1α), the key transcription factor mediating cellular hypoxic responses, to vascular remodeling is established, but not completely understood. In the angiotensin II (Ang II)-induced vascular remodeling model, HIF1α was increased and activated in vascular smooth muscle cells (VSMCs). Selective genetic disruption of Hif1a in VSMCs markedly ameliorated Ang II-induced vascular remodeling, as revealed by decreased blood pressure, aortic thickness, collagen deposition, inflammation, and aortic stiffness. VSMC Hif1a deficiency also specifically suppressed Ang II-induced infiltration of CD45+CD11b+F4/80+CD206- M1 macrophages into the vessel. Mechanistically, HIF1α deficiency in VSMCs dramatically suppressed the expression of CCL7, a chemokine critical for macrophage recruitment. Bioinformatic analysis and chromatin immunoprecipitation assays revealed three functional hypoxia-response elements in the Ccl7 promoter, indicating that Ccl7 is a direct HIF1α target gene. Blocking CCL7 with antibody in vivo alleviated Ang II-induced hypertension and vascular remodeling, coincident with decreased macrophage infiltration. This study provides direct evidence that HIF1α activation in VSMCs exacerbates Ang II-induced macrophage infiltration and resultant vascular remodeling via its target gene Ccl7, and thus may serve as a potential therapeutic target for remodeling-related vascular disease.

Recent trends in analytical methods for the determination of amino acids in biological samples.

Amino acids are widely distributed in biological fluids and involved in many biological processes, such as the synthesis of proteins, fatty acids, and ketone bodies. The altered levels of amino acids in biological fluids have been found to be closely related to several diseases, such as type 2 diabetes, kidney disease, liver disease, and cancer. Therefore, the development of analytical methods to measure amino acid concentrations in biological samples can contribute to research on the physiological actions of amino acids and the prediction, diagnosis and understanding of diseases. This review describes the analytical methods reported in 2012-2016 that utilized liquid chromatography and capillary electrophoresis coupled with ultraviolet, fluorescence, mass spectrometry, and electrochemical detection. Additionally, the relationship between amino acid concentrations and several diseases is also summarized.

Purification and characterization of a trypsin inhibitor from the seeds of Artocarpus heterophyllus Lam.

A proteinaceous inhibitor against trypsin was isolated from the seeds of Artocarpus heterophyllus Lam. by successive ammonium sulfate precipitation, ion-exchange, and gel-filtration chromatography. The trypsin inhibitor, named as AHLTI (A. heterophyllus Lam. trypsin inhibitor), consisted of a single polypeptide chain with a molecular weight of 28.5 kDa, which was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel-filtration chromatography. The N-terminal sequence of AHLTI was DEPPSELDAS, which showed no similarity to other known trypsin inhibitor sequence. AHLTI completely inhibited bovine trypsin at a molar ratio of 1:2 (AHLTI:trypsin) analyzed by native polyacrylamide gel electrophoresis, inhibition activity assay, and gel-filtration chromatography. Moreover, kinetic enzymatic studies were carried out to understand the inhibition mechanism of AHLTI against trypsin. Results showed that AHLTI was a competitive inhibitor with an equilibrium dissociation constant (Ki) of 3.7 × 10(-8) M. However, AHLTI showed weak inhibitory activity toward chymotrypsin and elastase. AHLTI was stable over a broad range of pH 4-8 and temperature 20-80°C. The reduction agent, dithiothreitol, had no obvious effect on AHLTI. The trypsin inhibition assays of AHLTI toward digestive enzymes from insect pest guts in vitro demonstrated that AHLTI was effective against enzymes from Locusta migratoria manilensis (Meyen). These results suggested that AHLTI might be a novel trypsin inhibitor from A. heterophyllus Lam. belonging to Kunitz family, and play an important role in protecting from insect pest.