A homozygous missense mutation in the fibroblast growth factor 5 gene is associated with the long-hair trait in Angora rabbits

BACKGROUND

Rabbits are well-domesticated animals. As a crucial economic animal, rabbit has been successfully bred into wool-use, meat-use and fur-use breeds. Hair length is one of the most economically important traits affecting profitability in wool rabbits. In this study, to identify selection signatures with the long-hair trait, whole-genomic resequencing of long-haired rabbits (Angora rabbits) and short-haired rabbits (Rex and New Zealand rabbits) was performed.

RESULTS

By genome-wide selective sweeping analysis based on population comparison, we identified a total of 5.85 Mb regions (containing 174 candidate genes) with strong selection signals. Six of these genes (Dusp1, Ihh, Fam134a, Map3k1, Spata16, and Fgf5) were enriched in the MAPK signalling and Hedgehog signalling pathways, both of which are closely associated with hair growth regulation. Among these genes, Fgf5 encodes the FGF5 protein, which is a well-established regulator of hair growth. There was a nonsynonymous nucleotide substitution (T19234C) in the Fgf5 gene. At this locus, the C allele was present in all of the tested Angora rabbits, while the T allele was dominant in New Zealand and Rex rabbits. We further confirmed that the C allele was conserved in Angora rabbits by screening an additional 135 rabbits. Moreover, the results of functional predictions and co-immunoprecipitation revealed that the T19234C mutation impaired the binding capacity of FGF5 to its receptor FGFR1.

CONCLUSIONS

We discovered that the homozygous missense mutation T19234C within Fgf5 might contribute to the long-hair trait of Angora rabbits by reducing its receptor binding capacity. This finding will provide new insights into the genetic basis underlying the genetic improvement of Angora rabbits and benefit the improvement of rabbit breeding in the future.

DT-109 ameliorates nonalcoholic steatohepatitis in nonhuman primates

Nonalcoholic steatohepatitis (NASH) prevalence is rising with no pharmacotherapy approved. A major hurdle in NASH drug development is the poor translatability of preclinical studies to safe/effective clinical outcomes, and recent failures highlight a need to identify new targetable pathways. Dysregulated glycine metabolism has emerged as a causative factor and therapeutic target in NASH. Here, we report that the tripeptide DT-109 (Gly-Gly-Leu) dose-dependently attenuates steatohepatitis and fibrosis in mice. To enhance the probability of successful translation, we developed a nonhuman primate model that histologically and transcriptionally mimics human NASH. Applying a multiomics approach combining transcriptomics, proteomics, metabolomics, and metagenomics, we found that DT-109 reverses hepatic steatosis and prevents fibrosis progression in nonhuman primates, not only by stimulating fatty acid degradation and glutathione formation, as found in mice, but also by modulating microbial bile acid metabolism. Our studies describe a highly translatable NASH model and highlight the need for clinical evaluation of DT-109.

MED1 Deficiency in Macrophages Aggravates Isoproterenol-Induced Cardiac Fibrosis in Mice

Mediator 1 (MED1), a key subunit of the mediator complex, interacts with various nuclear receptors and functions in lipid metabolism and energy homeostasis. Dilated cardiomyopathy-related ventricular dilatation and heart failure have been reported in mice with cardiomyocyte-specific Med1 deficiency. However, the contribution of macrophage-specific MED1 in cardiac remodeling remains unclear. In this study, macrophage-specific Med1 knockout (Med1^ΔMac) mice were generated and exposed to isoproterenol (ISO) to induce cardiac fibrosis; these mice showed aggravated cardiac fibrosis compared with Med1^fl/fl mice. The levels of expression of marker genes for myofibroblast transdifferentiation [α-smooth muscle actin (SMA)] and of profibrotic genes, including Col1a1, Col3a1, Postn, Mmp2, Timp1, and Fn1, were significantly increased in the cardiac tissues of Med1^ΔMac mice with ISO-induced myocardial fibrosis. In particular, the transforming growth factor (TGF)-β-Smad2/3 signaling pathway was activated. In bone marrow-derived and peritoneal macrophages, Med1 deficiency was also associated with elevated levels of expression of proinflammatory genes, including Il6, Tnfa, and Il1b. These findings indicate that macrophage-specific MED1 deficiency may aggravate ISO-induced cardiac fibrosis via the regulation of the TGF-β-SMAD2/3 pathway, and the underlying mechanism may involve MED1 deficiency triggering the activation of inflammatory cytokines in macrophages, which in turn may stimulate phenotypic switch of cardiac fibroblasts and accelerate cardiac fibrosis. Thus, MED1 is a potential therapeutic target for cardiac fibrosis.

Third-generation sequencing: A novel tool detects complex variants in the α-thalassemia gene

OBJECTIVE

Thalassemia is a monogenic disorder with a high carrier rate in the southern region of China. Most laboratories currently follow the protocol of testing hematologic indicators in individuals with positive hematologic indicators and then using the hot-spot mutation test kit. A novel thalassemia gene test is performed if there is a mismatch between the hematology and hot-spot mutation test results. However, due to the large population in southern China, some individuals carry complex α-globin gene cluster (CAGC) variants in NG_000006.1, which are difficult to detect using conventional thalassemia genetic analysis protocols, leading to missed or false genetic test results for individuals carrying these complex α-globin gene cluster variants. When an individual carries a complex α-thalassemia gene variant, and an individual carries a β- thalassemia gene variant, there may be clinical symptoms that might complicate clinical consultation and prenatal diagnosis if not accurately detected. Third-generation sequencing (TGS) enables long-read single-molecule sequencing with high detection accuracy, and long-length DNA chain reads in high-fidelity reads mode. TGS can be used to analyze high homology and rich GC DNA sequences.

RESULTS

Four samples that showed abnormalities in the thalassemia genetic test were studied using TGS, revealing that they carried genotypes with complex α-globin gene cluster variants, one of which was a complex variant αα anti3.7 α anti3.7 α 17.2.

CONCLUSIONS

TGS detects complex α-globin gene cluster variants. This study may provide a reference protocol for the use of TGS for the detection of complex α-globin gene cluster variants. TGS can reveal individuals with complex α-thalassemia genotypes in the population and improve the accuracy of genetic counseling and prenatal diagnosis.

TMT-based quantitative proteomic profiling of human monocyte-derived macrophages and foam cells

BACKGROUND

Cardiovascular diseases remain the leading cause of morbidity and mortality worldwide, most of which are caused by atherosclerosis. Discerning processes that participate in macrophage-to-foam cell formation are critical for understanding the basic mechanisms underlying atherosclerosis. To explore the molecular mechanisms of foam cell formation, differentially expressed proteins were identified.

METHODS

Human peripheral blood mononuclear cells were stimulated with macrophage colony-stimulating factor, and obtained macrophages were transformed into foam cells by oxidized low-density lipoprotein. Tandem mass tag (TMT) labeling combined with mass spectrometry was performed to find associations between foam cell transformation and proteome profiles.

RESULTS

Totally, 5146 quantifiable proteins were identified, among which 1515 and 182 differentially expressed proteins (DEPs) were found in macrophage/monocyte and foam cell/macrophage, respectively. Subcellular localization analysis revealed that downregulated DEPs of macrophages/monocytes were mostly located in the nucleus, whereas upregulated DEPs of foam cells/macrophages were mostly extracellular or located in the plasma membrane. Functional analysis of DEPs demonstrated that cholesterol metabolism-related proteins were upregulated in foam cells, whereas immune response-related proteins were downregulated in foam cells. The protein interaction network showed that the DEPs with the highest interaction scores between macrophages and foam cells were mainly concentrated in lysosomes and the endoplasmic reticulum.

CONCLUSIONS

Proteomics analysis suggested that cholesterol metabolism was upregulated, while the immune response was suppressed in foam cells. KEGG enrichment analysis and protein-protein interaction analysis indicated that DEPs located in the endoplasmic reticulum and lysosomes might be key drivers of foam cell formation. These data provide a basis for identifying the potential proteins associated with the molecular mechanism underlying macrophage transformation to foam cells.

Global Trends in Atherosclerosis Research in the Epigenetics Field: Bibliometric and Visualization Studies

Atherosclerosis is a pathological vascular state caused by the interaction of environmental and hereditary factors. Epigenetic modifications may be the bridge connecting environmental factors and genetic factors. A search for publications on the Web of Science database in the field of atherosclerosis related to epigenetics was conducted from the earliest mention to 31 December 2020. Data on total and annual publications, citations, impact factors, Hirsch (H)-index, citation times, most prolific authors, and frequently published journals were collected for quantitative and qualitative comparison. A total of 1848 publications related to epigenetics and atherosclerosis were found. The major contributing countries were the China (522, 28.23%), United States (485, 26.23%), and Germany (119, 6.44%). The greatest number of retrieved publications were published in the journal, "Arteriosclerosis, Thrombosis, and Vascular Biology" (62, 3.66%). The publication "Oxidative Stress and Diabetic Complications" was cited 2370 times. The most frequent keywords were "DNA methylation" and "LncRNA". Publications on epigenetic research in the atherosclerosis field have increased significantly every year, indicating that the study of epigenetic modifications plays an increasingly important role in understanding the pathology of atherosclerosis.

MED1 Deficiency in Macrophages Accelerates Intimal Hyperplasia via ROS Generation and Inflammation

Mediator complex subunit 1 (MED1) is a component of the mediator complex and functions as a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Previously, we showed that MED1 in macrophages has a protective effect on atherosclerosis; however, the effect of MED1 on intimal hyperplasia and mechanisms regulating proinflammatory cytokine production after macrophage MED1 deletion are still unknown. In this study, we report that MED1 macrophage-specific knockout (MED1 ^ΔMac) mice showed aggravated neointimal hyperplasia, vascular smooth muscle cells (VSMCs), and macrophage accumulation in injured arteries. Moreover, MED1 ^ΔMac mice showed increased proinflammatory cytokine production after an injury to the artery. After lipopolysaccharide (LPS) treatment, MED1 ^ΔMac macrophages showed increased generation of reactive oxygen species (ROS) and reduced expression of peroxisome proliferative activated receptor gamma coactivator-1α (PGC1α) and antioxidant enzymes, including catalase and glutathione reductase. The overexpression of PGC1α attenuated the effects of MED1 deficiency in macrophages. In vitro, conditioned media from MED1 ^ΔMac macrophages induced more proliferation and migration of VSMCs. To explore the potential mechanisms by which MED1 affects inflammation, macrophages were treated with BAY11-7082 before LPS treatment, and the results showed that MED1 ^ΔMac macrophages exhibited increased expression of phosphorylated-p65 and phosphorylated signal transducer and activator of transcription 1 (p-STAT1) compared with the control macrophages, suggesting the enhanced activation of NF-κB and STAT1. In summary, these data showed that MED1 deficiency enhanced inflammation and the proliferation and migration of VSMCs in injured vascular tissue, which may result from the activation of NF-κB and STAT1 due to the accumulation of ROS.

Dogs lacking Apolipoprotein E show advanced atherosclerosis leading to apparent clinical complications

Atherosclerotic cardiovascular disease resulting from dysregulated lipid metabolism is the leading cause of morbidity and mortality worldwide. Apolipoprotein E (ApoE) plays a critical role in cholesterol metabolism. Knockouts in lipid-metabolizing proteins including ApoE in multiple model organisms such as mice and rats exhibiting elevated levels of cholesterol have been widely used for dissecting the pathology of atherosclerosis, but few of these animal models exhibit advanced atherosclerotic plaques leading to ischemia-induced clinical symptoms, limiting their use for translational studies. Here we report hypercholesterolemia and severe atherosclerosis characterized by stenosis and occlusion of arteries, together with clinical manifestations of stroke and gangrene, in ApoE knockout dogs generated by CRISPR/Cas9 and cloned by somatic cell nuclear transfer technologies. Importantly, the hypercholesterolemia and atherosclerotic complications in F0 mutants are recapitulated in their offspring. As the ApoE-associated atherosclerosis and clinical manifestations in mutant dogs are more similar to that in human patients compared with those in other animal models, these mutant dogs will be invaluable in developing and evaluating new therapies, including endovascular procedures, against atherosclerosis and related disorders.

Changes in gut microbiota composition and diversity associated with post-cholecystectomy diarrhea

BACKGROUND

Post-cholecystectomy diarrhea (PCD) frequently occurs in patients following gallbladder removal. PCD is part of the post-cholecystectomy (PC) syndrome, and is difficult to treat. After cholecystectomy, bile enters the duodenum directly, independent of the timing of meals. The interaction between the bile acids and the intestinal microbes is changed. Therefore, the occurrence of PCD may be related to the change in microbiota. However, little is known about the relationship between the gut microbiota and PCD.

AIM

To better understand the role of the gut microbiota in PCD patients.

METHODS

Fecal DNA was isolated. The diversity and profiles of the gut microbiota were analyzed by performing high-throughput 16S rRNA gene sequencing. The gut microbiota were characterized in a healthy control (HC) group and a PC group. Subsequently, the PC group was further divided into a PCD group and a post-cholecystectomy non-diarrhea group (PCND) according to the patients' clinical symptoms. The composition, diversity and richness of microbial communities were determined and compared.

RESULTS

In the PC and HC groups, 720 operational taxonomic units (OTUs) were identified. The PC group had fewer OTUs than the HC group. β-diversity was decreased in the PC group. This indicated decreased microbial diversity in the PC group. Fifteen taxa with differential abundance between the HC and PC groups were identified. In the PCD group compared to the PCND group, significant decreases in microbial diversity, Firmicutes/Bacteroidetes ratio, and richness of probiotic microbiota (Bifidobacterium and Lactococcus), and an increase in detrimental microbiota (Prevotella and Sutterella) were observed. Moreover, a negative correlation was found between Prevotella and Bifidobacterium. Using a Kyoto Encyclopedia of Genes and Genomes functional analysis, it was found that the abundances of gut microbiota involved in lipid metabolism pathways were markedly lower in the PCD group compared to the PCND group.

CONCLUSION

This study demonstrated that gut dysbiosis may play a critical role in PCD, which provides new insights into therapeutic options for PCD patients.

C-reactive protein and cardiovascular disease: From animal studies to the clinic (Review)

C-reactive protein (CRP) and cardiovascular disease (CVD) have long been important research topics. CRP is an acute phase protein, while CVD is an inflammatory condition. The association between CRP and CVD remains controversial and has been attracting increasing attention. Traditionally, the main marker of CVD is considered to be low-density lipoprotein cholesterol. However, due to its unique characteristics, CRP may represent a novel marker or a new therapeutic target for CVD. Clinical studies have demonstrated that CRP is a predictor of CVD, but whether it is directly involved in the development and progression of CVD has yet to be fully elucidated. Recent clinical studies have demonstrated that lowering plasma CRP levels may reduce the incidence of CVD. The aim of the present review was to investigate the association between CRP and CVD, particularly atherosclerosis, from laboratory animal studies to clinical research.

A Functional Genetic Variant at the C-Reactive Protein Promoter (rs3091244) Is Not Associated With Cancer Risk in a Chinese Population

Background: The association of genetically elevated levels of circulating C-reactive protein (CRP) with cancer risk has been extensively investigated in European populations; however, there are conflicting conclusions. The tri-allelic rs3091244 is a functionally validated genetic variant, and its allelic frequencies differ significantly between European and Asian populations. Here, we examined the association of rs3091244 with cancer risk in a Chinese population.

Methods: rs3091244 was genotyped by Sanger sequencing in 4,971 cancer cases and 2,485 controls. The rs1205 and rs2794521 gene variants were also genotyped using TaqMan assays in subgroups.

Results: No association was detected between the genotyped CRP variants and cancer risk, with or without distinguishing cancer types, suggesting that circulating CRP is not causally involved in tumorigenesis in Chinese populations.

Extracellular vesicles and melatonin benefit embryonic develop by regulating reactive oxygen species and 5-methylcytosine

Embryo culture conditions are crucial as they can affect embryo quality and even offspring. Oviductal extracellular vesicles (EVs) long been considered a major factor influencing interactions between the oviduct and embryos, and thus its absence is associated with inferior embryonic development in in vitro culture. Herein, we demonstrated that melatonin is present in oviduct fluids and oviduct fluid-derived EVs. Addition of either EVs (1.87 × 10¹¹ particles/mL) or melatonin (340 ng/mL) led to a significant downregulation of reactive oxygen species (ROS) and 5-methylcytosine (5-mC), as well as an increase in the blastocyst rate of embryos, which was inhibited by the addition of luzindole-a melatonin receptor agonist. A combination of EVs (1.87 × 10¹⁰ particles/mL) and melatonin (at 34.3 pg/mL) led to the same results as well as a significant decrease in the apoptosis index and increase in the inner cell mass (ICM)/trophectoderm (TE) index. These results suggest that an EV-melatonin treatment benefits embryonic development. Our findings provide insights into the role of EVs and melatonin during cell communication and provide new evidence of the communication between embryos and maternal oviduct.

Insights into the roles of sperm in animal cloning

Somatic cell nuclear transfer (SCNT) has shown a wide application in the generation of transgenic animals, protection of endangered animals, and therapeutic cloning. However, the efficiency of SCNT remains very low due to some poorly characterized key factors. Compared with fertilized embryos, somatic donor cells lack some important components of sperm, such as sperm small noncoding RNA (sncRNA) and proteins. Loss of these factors is considered an important reason for the abnormal development of SCNT embryo. This study focused on recent advances of SCNT and the roles of sperm in development. Sperm-derived factors play an important role in nucleus reprogramming and cytoskeleton remodeling during SCNT embryo development. Hence, considering the role of sperm may provide a new strategy for improving cloning efficiency.

Melatonin Protects Rabbit Somatic Cell Nuclear Transfer (SCNT) Embryos from Electrofusion Damage

The study’s objectives were to examine the effects of electrofusion on rabbit somatic cell nuclear transfer (SCNT) embryos, and to test melatonin as a protective agent against electrofusion damage to SCNT embryos. The levels of reactive oxygen species (ROS), the epigenetic state (H3K9me3), and the content of endoplasmic reticulum (ER) stress-associated transcripts (IRE-1 and CHOP) were measured. Melatonin was added during the preimplantation development period. The total blastocyst cell numbers were counted, and the fragmentation rate and apoptotic index were determined and used to assess embryonic development. Electrofusion increased (1) ROS levels at the 1-, 2-, 4-, and 8-cell stages; (2) H3K9me3 levels at the 2-, 4-, and 8-cell stage; and (3) the expression of IRE-1 and CHOP at the 8-cell, 16-cell, morula, and blastocyst stages. The treatment of SCNT embryos with melatonin significantly reduced the level of ROS and H3K9me3, and the expression levels of IRE-1 and CHOP. This treatment also significantly reduced the fragmentation rate and apoptotic index of blastocysts and increased their total cell number. In conclusion, the electrofusion of rabbit SCNT embryos induced oxidative stress, disturbed the epigenetic state, and caused ER stress, while melatonin reduced this damage. Our findings are of signal importance for improving the efficiency of SCNT and for optimizing the application of electrical stimulation in other biomedical areas.

Hypoxic and Cold Adaptation Insights from the Himalayan Marmot Genome

The Himalayan marmot (Marmota himalayana) is a hibernating mammal that inhabits the high-elevation regions of the Himalayan mountains. Here we present a draft genome of the Himalayan marmot, with a total assembly length of 2.47 Gb. Phylogenetic analyses showed that the Himalayan marmot diverged from the Mongolian marmot approximately 1.98 million years ago. Transcriptional changes during hibernation included genes responsible for fatty acid metabolism in liver and genes involved in complement and coagulation cascades and stem cell pluripotency pathways in brain. Two selective sweep genes, Slc25a14 and ψAamp, showed apparent genotyping differences between low- and high-altitude populations. As a processed pseudogene, ψAamp may be biologically active to influence the stability of Aamp through competitive microRNA binding. These findings shed light on the molecular and genetic basis underlying adaptation to extreme environments in the Himalayan marmot.

Genomic and Transcriptomic Analysis of Hypercholesterolemic Rabbits: Progress and Perspectives

Rabbits (Oryctolagus cuniculus) are one of the most widely used animal models for the study of human lipid metabolism and atherosclerosis because they are more sensitive to a cholesterol diet than other experimental animals such as rodents. Currently, two hypercholesterolemic rabbit models are frequently used for atherosclerosis studies. One is a cholesterol-fed wild-type rabbit and the other is the Watanabe heritable hyperlipidemic (WHHL) rabbit, which is genetically deficient in low density lipoprotein (LDL) receptor function. Wild-type rabbits can be easily induced to develop severe hypercholesterolemia with a cholesterol-rich diet due to the marked increase in hepatically and intestinally derived remnant lipoproteins, called β-very low density lipoproteins (VLDL), which are rich in cholesteryl esters. WHHL rabbits are characterized by elevated plasma LDL levels on a standard chow diet, which resembles human familial hypercholesterolemia. Therefore, both rabbit models develop aortic and coronary atherosclerosis, but the elevated plasma cholesterol levels are caused by completely different mechanisms. In addition, cholesterol-fed rabbits but not WHHL rabbits exhibit different degrees of hepatosteatosis. Recently, we along with others have shown that there are many differentially expressed genes in the atherosclerotic lesions and livers of cholesterol-fed rabbits that are either significantly up- or down-regulated, compared with those in normal rabbits, including genes involved in the regulation of inflammation and lipid metabolism. Therefore, dietary cholesterol plays an important role not only in hypercholesterolemia and atherosclerosis but also in hepatosteatosis. In this review, we make an overview of the recent progress in genomic and transcriptomic analyses of hypercholesterolemic rabbits. These transcriptomic profiling data should provide novel insight into the relationship between hypercholesterolemia and atherosclerosis or hepatic dysfunction caused by dietary cholesterol.

Western diet feeding influences gut microbiota profiles in apoE knockout mice

BACKGROUND

Gut microbiota plays an important role in many metabolic diseases such as diabetes and atherosclerosis. Apolipoprotein E (apoE) knock-out (KO) mice are frequently used for the study of hyperlipidemia and atherosclerosis. However, it is unknown whether apoE KO mice have altered gut microbiota when challenged with a Western diet.

METHODS

In the current study, we assessed the gut microbiota profiling of apoE KO mice and compared with wild-type mice fed either a normal chow or Western diet for 12 weeks using 16S pyrosequencing.

RESULTS

On a western diet, the gut microbiota diversity was significantly decreased in apoE KO mice compared with wild type (WT) mice. Firmicutes and Erysipelotrichaceae were significantly increased in WT mice but Erysipelotrichaceae was unchanged in apoE KO mice on a Western diet. The weighted UniFrac principal coordinate analysis exhibited clear separation between WT and apoE KO mice on the first vector (58.6%) with significant changes of two dominant phyla (Bacteroidetes and Firmicutes) and seven dominant families (Porphyromonadaceae, Lachnospiraceae, Ruminococcaceae, Desulfovibrionaceae, Helicobacteraceae, Erysipelotrichaceae and Veillonellaceae). Lachnospiraceae was significantly enriched in apoE KO mice on a Western diet. In addition, Lachnospiraceae and Ruminococcaceae were positively correlated with relative atherosclerosis lesion size in apoE KO.

CONCLUSIONS

Collectively, our study showed that there are marked changes in the gut microbiota of apoE KO mice, particularly challenged with a Western diet and these alterations may be possibly associated with atherosclerosis.

Transcriptomic analysis of the liver of cholesterol-fed rabbits reveals altered hepatic lipid metabolism and inflammatory response

Rabbits are a suitable animal model for atherosclerosis due to their sensitivity to dietary cholesterol. Moreover, rabbits have lipoprotein profiles that are more similar to humans than those of other laboratory animals. However, little is known about the transcriptomic information related to atherosclerosis in rabbits. We aimed to determine the changes in the livers of rabbits fed a normal chow diet (control) or high cholesterol diet (HCD) by histological examinations and RNA sequencing analysis. Compared with the control group, the lipid levels and small LDL subfractions in plasma were increased, and aortic atherosclerotic plaques were formed in the HCD group. Most importantly, HCD resulted in lipid accumulation and inflammation in the livers. Transcriptomic analysis of the liver showed that HCD induces 1183 differentially expressed genes (DEGs) that mainly participate in the regulation of inflammation and lipid metabolism. Furthermore, the signaling pathways involved in inflammation and lipid metabolism were enriched by KEGG pathway analysis. In addition, hepatic DEGs of the HCD group were further validated by real-time PCR. These results suggest that HCD causes liver lipid accumulation and inflammatory response. Although the relationships between these hepatic changes and atherogenesis need further investigation, these findings provide a fundamental framework for future research on human atherosclerosis using rabbit models.

Porcine reproductive and respiratory syndrome virus induces HMGB1 secretion via activating PKC-delta to trigger inflammatory response

Porcine reproductive and respiratory syndrome virus (PRRSV) causes inflammatory injuries in infected pigs. PRRSV induces secretion of high mobility group box 1 (HMGB1) that enhances inflammatory response. However, the mechanism of PRRSV-induced HMGB1 secretion is unknown. Here, we discovered PRRSV induced HMGB1 secretion via activating protein kinase C-delta (PKCδ). HMGB1 secretion was positively correlated with PKCδ activation in PRRSV-infected cells in a dose and time-dependent manner. Suppression of PKCδ with inhibitor and siRNA significantly blocked PRRSV-induced HMGB1 translocation and secretion, which indicates PKCδ activation is essential for the PRRSV-mediated HMGB1 secretion. In addition, PKCδ knockdown in PRRSV-infected cells led to downregulation of inflammatory cytokines, including IL-1beta and IL-6. Moreover, PRRSV E and pORF5a proteins were found to activate PKCδ and consequent HMGB1 secretion. These results demonstrate PRRSV activates PKCδ to induce HMGB1 secretion via E and pORF5a. This finding provides insights on the inflammatory response and pathogenesis of PRRSV infection.

Safety Assessment of Electronic Cigarettes and Their Relationship with Cardiovascular Disease

Smoking leads to the occurrence and development of a variety of diseases. Most importantly, it is an independent risk factor of cardiovascular atherosclerosis. In recent years, electronic cigarettes have become a popular alternative to traditional cigarettes, since modern micro-electronic techniques provide the possibility of simulating the process of traditional smoking. Additionally, it is convenient and fashionable. Nevertheless, comments about the safety of electronic cigarettes remain controversial. Although the research about electronic cigarettes increased exponentially, there has been no systematic study of its safety. The aim of the current study is to review the literature reports about the safety of electronic cigarettes, and to understand their hazards and disadvantages. It was found that most of the current research about electronic cigarettes comprises short-term and in vitro studies. There are few reports of in vivo and long-term studies. Notably, the level of harmful components such as volatile organic compounds, tobacco-specific nitrosamines and heavy metals in electronic cigarettes are even higher than in traditional cigarettes. Therefore, the harm of electronic cigarettes should not be underestimated. In conclusion, the question of whether electronic cigarettes are a safe and sufficient substitute for traditional smoking needs further investigation.

Overexpression of Cholesteryl Ester Transfer Protein Increases Macrophage-Derived Foam Cell Accumulation in Atherosclerotic Lesions of Transgenic Rabbits

High levels of plasma high-density lipoprotein-cholesterol (HDL-C) are inversely associated with the risk of atherosclerosis and other cardiovascular diseases; thus, pharmacological inhibition of cholesteryl ester transfer protein (CETP) is considered to be a therapeutic method of raising HDL-C levels. However, many CETP inhibitors have failed to achieve a clinical benefit despite raising HDL-C. In the study, we generated transgenic (Tg) rabbits that overexpressed the human CETP gene to examine the influence of CETP on the development of atherosclerosis. Both Tg rabbits and their non-Tg littermates were fed a high cholesterol diet for 16 weeks. Plasma lipids and body weight were measured every 4 weeks. Gross lesion areas of the aortic atherosclerosis along with lesional cellular components were quantitatively analyzed. Overexpression of human CETP did not significantly alter the gross atherosclerotic lesion area, but the number of macrophages in lesions was significantly increased. Overexpression of human CETP did not change the plasma levels of total cholesterol or low-density lipoprotein cholesterol but lowered plasma HDL-C and increased triglycerides. These data revealed that human CETP may play an important role in the development of atherosclerosis mainly by decreasing HDL-C levels and increasing the accumulation of macrophage-derived foam cells.

Osteoprotective Effect of Radix Scutellariae in Female Hindlimb-Suspended Sprague-Dawley Rats and the Osteogenic Differentiation Effect of Its Major Constituent

A number of medicinal herbs have demonstrated therapeutic effects for the prevention and treatment of disuse-induced osteoporosis. As a common ingredient in proprietary traditional Chinese medicines, the anti-osteoporosis effects of Radix Scutellariae extract (RSE, 50 mg/kg/day) were evaluated in a hindlimb suspended rat model. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry, and the micro-architecture observed by MicroCT assay with bone biomechanical properties evaluated by a three-point bending test. To elucidate potential mechanisms, the osteogenic differentiation effect of baicalin as the most abundant ingredient in RSE was investigated in rat bone marrow derived mesenchymal stem cells (rBMSC). After drug administration for 42 days, tibia-BMD was significantly increased to 0.176 ± 0.007 and 0.183 ± 0.011 g/cm² and f-BMD was enhanced to 0.200 ± 0.017 and 0.207 ± 0.021 g/cm² for RSE and ALE treatment, respectively, whereas tibia-BMD and femur-BMD of the HLS group were 0.157 ± 0.009 and 0.176 ± 0.008 g/cm². Deterioration of bone trabecula microstructure was improved by RSE and ALE with increased morphological parameters such as bone volume fraction, trabecular thickness, and trabecular number, as well as connectivity density compared to the HLS group (p < 0.01). A three-point bending test suggested that bone mechanical strength was also enhanced by RSE and ALE treatments with increased maximum stress, young’s modulus, maximum load, and stiffness compared to those of the HLS group (p < 0.05). Besides, serum TRACP levels were significantly suppressed by RSE and ALE treatments. Furthermore, in vitro studies demonstrated that baicalin significantly increased ALP activities and the formation of mineralized nodules in rBMSC. Conclusively, supplementation of RSE could significantly prevent weightlessness induced osteoporosis, which might attribute to the osteogenic differentiation enhancement effect of baicalin.

Mediator 1 Is Atherosclerosis Protective by Regulating Macrophage Polarization

OBJECTIVE

MED1 (mediator 1) interacts with transcription factors to regulate transcriptional machinery. The role of MED1 in macrophage biology and the relevant disease state remains to be investigated.

APPROACH AND RESULTS

To study the molecular mechanism by which MED1 regulates the M1/M2 phenotype switch of macrophage and the effect on atherosclerosis, we generated MED1/apolipoprotein E (ApoE) double-deficient (MED1^ΔMac/ApoE^-/-) mice and found that atherosclerosis was greater in MED1^ΔMac/ApoE^-/- mice than in MED1^fl/fl/ApoE^-/- littermates. The gene expression of M1 markers was increased and that of M2 markers decreased in both aortic wall and peritoneal macrophages from MED1^ΔMac/ApoE^-/- mice, whereas MED1 overexpression rectified the changes in M1/M2 expression. Moreover, LDLR (low-density lipoprotein receptor)-deficient mice received bone marrow from MED1^ΔMac mice showed greater atherosclerosis. Mechanistically, MED1 ablation decreased the binding of PPARγ (peroxisome proliferator-activated receptor γ) and enrichment of H3K4me1 and H3K27ac to upstream region of M2 marker genes. Furthermore, interleukin 4 induction of PPARγ and MED1 increased the binding of PPARγ or MED1 to the PPAR response elements of M2 marker genes.

CONCLUSIONS

Our data suggest that MED1 is required for the PPARγ-mediated M2 phenotype switch, with M2 marker genes induced but M1 marker genes suppressed. MED1 in macrophages has an antiatherosclerotic role via PPARγ-regulated transactivation.

Bre Enhances Osteoblastic Differentiation by Promoting the Mdm2-Mediated Degradation of p53

Bre is a conserved cellular protein expressed in various tissues. Its major function includes DNA damage repair and anti-apoptosis. Recent studies indicate that Bre is potentially involved in stem cell differentiation although pathophysiological significance along with the molecular mechanisms is still unclear. Here, we report that Bre protein was substantially expressed in the bone tissue and its expression was highly upregulated during the osteogenic differentiation. To test a hypothesis that Bre plays functional roles in the process of osteogenic differentiation, we examined the expression of Bre in an osteoporosis mouse model. Compared with the normal bone tissue, Bre expression in osteoporotic bone was also significantly reduced. Moreover, knockdown of Bre in the mouse bone marrow mesenchymal cells significantly reduced the expression of osteogenic marker genes, the alkaline phosphatase activity, and the mineralization capacity, while overexpression of Bre greatly promoted the osteogenesis both in vitro and in vivo. Interestingly, we founded that knockdown of Bre led to activation of the p53 signaling pathways exhibited by increased p53, p21, and Mdm2. However, when we inhibited the p53 by siRNA silencing or pifithrin-α, the impaired osteogenesis caused by Bre knockdown was greatly restored. Finally, we found that Bre promoted the Mdm2-mediated p53 ubiquitination and degradation by physically interacting with p53. Taken together, our results revealed a novel function of Bre in osteoblast differentiation through modulating the stability of p53. Stem Cells 2017;35:1760-1772.