PURPOSE: Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to the low density lipoprotein receptor (LDLR) and promotes degradation of the LDLR. Inhibition of PCSK9 either by reducing its expression or by blocking its activity results in the upregulation of the LDLR and subsequently lowers the plasma concentration of LDL-cholesterol. As a modality to inhibit PCSK9 action, we searched the chemical library for small molecules that block the binding of PCSK9 to the LDLR. MATERIALS AND METHODS: We selected 100 chemicals that bind to PCSK9 where the EGF-AB fragment of the LDLR binds via in silico screening of the ChemBridge chemical library, using the computational GOLD algorithm analysis. Effects of chemicals were evaluated using the PCSK9-LDLR binding assay, immunoblot analysis, and the LDL-cholesterol uptake assay in vitro, as well as the fast performance liquid chromatography assay for plasma lipoproteins in vivo. RESULTS: A set of chemicals were found that decreased the binding of PCSK9 to the EGF-AB fragment of the LDLR in a dose-dependent manner. They also increased the amount of the LDLR significantly and subsequently increased the uptake of fluorescence-labeled LDL in HepG2 cells. Additionally, one particular molecule lowered the plasma concentration of total cholesterol and LDL-cholesterol significantly in wild-type mice, while such an effect was not observed in Pcsk9 knockout mice. CONCLUSION: Our findings strongly suggest that in silico screening of small molecules that inhibit the protein-protein interaction between PCSK9 and the LDLR is a potential modality for developing hypercholesterolemia therapeutics.
Animals ; Cholesterol/*blood ; Cholesterol, LDL/blood ; Hep G2 Cells ; Humans ; Mice ; Mice, Knockout ; Proprotein Convertases/*metabolism ; Receptors, LDL/*metabolism ; Serine Endopeptidases/*metabolism ; *Small Molecule Libraries

OBJECTIVETo report the clinical data of a case of iron-refractory iron deficiency anemia (IRIDA), so as to improve the understanding of IRIDA.

METHODSThe IRIDA patient's hematological characteristics were summarized and analyzed. The hepcidin levels were tested by ELISA kit. The TMPRSS6 gene was amplified by PCR reaction and its mutation was analyzed by sequencing. The effect of TMPRSS6 gene mutation on TMPRSS6 protein tertiary structure was predicted by Swiss-Model.

RESULTSThe patient was characterized by typical microcytic hypochromic anemia, low transferrin saturation, more reduction of intracellular iron than exocellular iron. The plasma hepcidin level was 213.77 μg/L which was significantly higher than that of IDA patients [5.19(3.31-12.02) μg/L]. The patient also carried a homozygous missense mutation of K253E in exon 7 of TMPRSS6.

CONCLUSIONIn children and younger IDA patients with no reason for iron deficiency but unresponsiveness to routine iron treatment, the diagnosis of IRIDA needs to be considered. Serum hepcidin level and TMPRSS6 gene mutation should be detected.

Anemia, Iron-Deficiency ; blood ; genetics ; Female ; Hepcidins ; blood ; Humans ; Membrane Proteins ; genetics ; Mutation ; Protein Structure, Tertiary ; Serine Endopeptidases ; genetics ; Young Adult

OBJECTIVE: To investigate the relationship between tryptase in serum and anaphylaxis. METHODS: The concentrations of tryptase in the sera of heart blood in three persons died from anaphylaxis shock were detected by ELISA. The first sample was obtained from a man, aged 38, died of injecting Amikacin. The second sample was obtained from a man, aged 42, died of injecting Cephradine. The third sample was from a woman, aged 39, died of injecting Lincomycin. All samples were stored in -20 degrees C. RESULTS: The concentrations of tryptase in sera were 52 ng/ml, 121 ng/ml and 0.73 ng/ml. It was unknown why the concentration of tryptase in the third sample was normal. CONCLUSION In fetal anaphylaxia reaction tryptase measurement is a useful indicator, but the diagnosis is not to be based on the test alone.
Adult ; Anaphylaxis/enzymology* ; Biomarkers/blood* ; Cause of Death ; Enzyme-Linked Immunosorbent Assay ; Female ; Forensic Medicine ; Humans ; Male ; Mast Cells/enzymology* ; Postmortem Changes ; Retrospective Studies ; Serine Endopeptidases/blood* ; Tryptases

BACKGROUNDFamilial hypercholesterolemia (FH) is an autosomal disorder associated with elevated plasma low density lipoprotein (LDL) levels leading to premature coronary heart disease (CHD). As a result of long-term hyperlipemia, FH patients will present endarterium thickening and artherosclerosis. In the present study we scanned the related gene of a clinically diagnosed autosomal genetic hypercholesterolemia family for the possible mutations and established eukaryotic expression vector of mutation of proprotein convertase subtilisin/kexin type 9 (PCSK9) gene with gene recombination technique to investigate the contributions of the variation on low density lipoprotein receptor (LDL-R) metabolism and function alternation.

METHODSMutation detection was conducted for LDL-R, apolipoprotein B(100) (apoB(100)) and PCSK9 gene with nucleotide sequencing in a Chinese FH family. The full-length cDNA of wild type PCSK9 gene (WT-PCSK9) was obtained from Bel-7402. Site mutagenesis was used to establish the recombinant eukaryotic expression vector carrying pathogenic type of PCSK9 gene and the inserted fragment was sequenced. With the blank vector as control, liposome transfection method was used to transfect the Bel-7402 cells with recombinant plasmid. The expression of LDL-R mRNA was examined by RT-PCR. PCSK9 and the expression of LDL-R protein were determined by Western blotting.

RESULTSThe G-->T mutation at the 918 nucleotide of PCSK9 gene resulted in the substitution of the arginine by a serine at the codon 306 of exon 6. After sequencing, it was confirmed that the inserted fragment of established expression vector had correct size and sequence and the mutant was highly expressed in Bel-7402 cells. There was no significant variation in the levels of LDL-R mRNA. LDL-R mature protein was decreased by 57% after the cells were transfected by WT-PCSK9 plasmid. Mature LDL-R was significantly decreased by 12% after the cells were transfected by R306S mutant as evidenced by gray scale scanning, suggesting that the new mutant R306S can significantly decrease the expression of mature LDL-R protein.

CONCLUSIONSA novel missense mutation of PCSK9 gene, R306S, was found and the eukaryotic expression vectors of mutant and wild-type of PCSK9 gene were established. There was no significant variation in the levels of LDL-R mRNA. The R306S mutation could significantly lead to the decrease of LDL-R mature protein expression, which might be the pathogenic gene of the FH family.

Adolescent ; Adult ; Female ; Humans ; Hyperlipoproteinemia Type II ; genetics ; Lipids ; blood ; Male ; Mutation ; Pedigree ; Proprotein Convertase 9 ; Proprotein Convertases ; Serine Endopeptidases ; genetics

BACKGROUNDIn a previously identified locus linked to hypertension on chromosome 15q, we identified three blood pressure candidate genes: insulin-like growth factor 1 receptor gene (IGF1R), myocyte specific enhancer factor 2A gene (MEF2A), and paired basic amino acid cleaving enzyme 4 gene (PACE4). In this study, we tested their associations with hypertension using haplotype analysis.

METHODSA total of 288 unrelated individuals, including 163 high diastolic blood pressure (DBP) subjects and 125 normal DBP subjects were enrolled in this case-control study. Twenty single nucleotide polymorphisms (SNPs) in the three genes were genotyped using polymerase chain reaction followed by restriction enzyme digestion. Haplotype analysis was accomplished in the following stages: (1) pair-wise linkage disequilibrium test among SNPs on the same gene was performed to explore blocks in which recombination is very unlikely to happen; (2) Estimation-Maximization algorithm was applied to estimate haplotype frequencies in each block; (3) the chi-square test was used to examine the specific haplotype difference, and a permutation test was used to examine the overall haplotype profile difference between cases and controls in each block.

RESULTSAn estimated haplotype "CCCCG" frequency in the haplotype block on the PACE4 gene was significantly higher in high DBP cases than in controls (P < 0.01). The overall estimated haplotype profile in this block was also significantly different between the cases and the controls (P < 0.001). This association indicates.

CONCLUSIONSThis study for the first time demonstrated that PACE4 gene may play an important role in the regulation of DBP. This association indicates that variations influencing DBP resides in or near this genomic region.

Adult ; Blood Pressure ; physiology ; Case-Control Studies ; Diastole ; physiology ; Female ; Haplotypes ; Humans ; Male ; Polymorphism, Single Nucleotide ; Proprotein Convertases ; Serine Endopeptidases ; genetics

OBJECTIVEAntineutrophil cytoplasmic antibody (ANCA) associated small vasculitides (ASV) are rare in children and often complicated in clinical manifestations and have very poor prognosis. In order to deepen our understanding of ANCA-associated small vasculitis (ASV) in children, the present study aimed to characterize their clinical manifestations, serum ANCA and renal histopathological findings and outcomes in Chinese children.

METHODSSerum ANCA was qualitatively tested with indirect immunofluorescence microscopy and anti-proteinase 3 (PR(3)) and anti-myeloperoxidase (MPO) activity were quantitated by enzyme-linked immunosorbent assays (ELISA), and renal biopsies were done to investigate the pathological changes. The clinical manifestation, serum ANCA and renal histopathological findings and outcome were characterized in 5 children with ANCA associated small vasculitis.

RESULTS(1) Five children with ANCA associated small vasculitis only accounted for 1.20% of children in whom renal biopsy was performed and 0.25% of hospitalized children with renal diseases during the same period. The age of onset of the 5 children with ASV was between 8 to 12 years with mean age 10.5 years. All ASV children were female. (2) All ASV children were negative for C-ANCA and showed normal anti-proteinase 3 activities, but positive for P-ANCA with high anti-myeloperoxidase activities between 98 to 242 kEU/L. The mean value of MPO-ANCA was 154.5 kEU/L (normal range < 12.7 kEU/L). (3) All ASV in the children was microscopic polyarteritis with wide-spread glomerular crescents formation and capillary tuft fibrinoid necrosis. Variety of complement C3 deposits and weak immunoglobulin deposits were noted in all ASV but one child who showed relatively strong deposits of IgA and IgM. The electronic dense deposits were mainly located in subendothelial space but were also found in the glomerular basement membrane in one child. (4) Three children with ASV died within one year after diagnosis, and two got remission and restored renal function after combined pulse therapy with methylprednisolone and cyclophosphamide (CTX), but remained to have hematuria and small amount of proteinuria after 1 and 5 year follow-up, respectively.

CONCLUSIONChildhood ASV was female and P-ANCA predominant, more vulnerable to progress to renal failure and poorer in prognosis than adult cases. Qualitative and quantitative ANCA measurement and renal biopsy were key to the diagnosis of ASV in children.

Antibodies, Antineutrophil Cytoplasmic ; blood ; Biopsy ; Child ; Enzyme-Linked Immunosorbent Assay ; Female ; Fluorescent Antibody Technique, Indirect ; Humans ; Kidney ; pathology ; Kidney Function Tests ; Myeloblastin ; Peroxidase ; metabolism ; Prognosis ; Renal Insufficiency ; etiology ; pathology ; Serine Endopeptidases ; metabolism ; Vasculitis ; blood ; complications ; therapy

BACKGROUNDPrevious studies have indicated that thrombin (TM) may play a major role in brain edema after intracerebral hemorrhages (ICHs). However, the mechanism of TM-induced brain edema is poorly understood. In this study, we explored the effect of TM on the permeability of the blood brain barrier (BBB) and investigated its possible mechanism, aiming at providing a potential target for brain edema therapy after ICHs.

METHODSTM or TM + cathepsin G (CATG) was stereotaxically injected into the right caudate nucleus of Sprague-Dawley rats in vivo. BBB permeability was measured by Evans-Blue extravasation. Brain water content was determined by the dry-wet weight method. Brain microvascular endothelial cells were then cultured in vitro. After TM or TM + CATG was added to the endothelial cell medium, changes in the morphology of cells were dynamically observed by phase-contrast light microscopy, and the expression of matrix metalloproteinase-2 (MMP-2) protein was measured by immunohistochemical method.

RESULTSBBB permeability increased at 6 hours after a TM injection into the ipsilateral caudate nucleus (P < 0.05), peaked between 24 hours (P < 0.01) and 48 hours (P < 0.05) after the injection, and then declined. Brain water content changed in parallel with the changes in BBB permeability. However, at all time points, BBB permeability and brain water content after a TM + CATG injection were not significantly different from the respective parameters in the control group (P > 0.05). TM induced endothelial cell contraction in vitro in a time-dependent manner and enhanced the expression of MMP-2 protein. After incubation with TM + CATG, cell morphology and MMP-2 expression did not change significantly as compared to the control group (P > 0.05).

CONCLUSIONSIncreased BBB permeability may be one of the mechanisms behind TM-induced cerebral edema. TM induces endothelial cell contraction and promotes MMP-2 expression by activating protease activated receptor-1 (PAR-1), possibly leading to the opening of the BBB.

Animals ; Blood-Brain Barrier ; drug effects ; Body Water ; metabolism ; Brain Edema ; etiology ; Cathepsin G ; Cathepsins ; pharmacology ; Cerebral Hemorrhage ; complications ; Matrix Metalloproteinase 2 ; analysis ; Permeability ; Rats ; Rats, Sprague-Dawley ; Receptor, PAR-1 ; physiology ; Serine Endopeptidases ; Thrombin ; toxicity

OBJECTIVETo investigate the effect and molecular mechanisms of different doses of 8-hydroxy dihydroberberine (Hdber) for the treatment of hyperlipidemia in rats.

METHODSA rat model of hyperlipidemia was established by feeding rats a high-fat diet for 4 weeks in 70 rats of 80 animals, and 10 rats were randomly selected as control group. The hyperlipidemic rats were then randomly divided into the following groups: a model group (MOD); a berberine group [BBR, 156 mg/(kg day)]; Hdber groups, which were treated with different doses of Hdber [78, 39 and 19.5 mg/(kg day)]; and a simvastatin group [SIM, 4 mg/(kg day)]. The corresponding therapy was administered to the rats of each treatment via gastric tubes. Normal animals were used as a control group. The blood levels of various lipids, including total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, free fatty acid (FFA), apolipoprotein AI(Apo-AI) and apolipoprotein B (Apo-B) were examined. The protein expressions of low-density lipoprotein receptor (LDL-R), sterol regulatory element-binding protein 2 (SREBP-2), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and proprotein convertase subtilisin/kexin type 9 (PCSK-9) in liver tissues were determined by Western blot analysis.

RESULTSCompared with the control group of rats, the model group demonstrated a deteriorated blood lipid profile and exhibited increased expression levels of PCSK-9 protein in their liver tissues (P<0.01). In addition, the high-fat diet decreased the expression levels of LDL-R, SREBP-2 and HMGCR proteins in murine liver tissues. However, the addition of berberine or Hdber reversed the blood lipid profile changes (P<0.05 or P<0.01), decreased the expression levels of PCSK-9 proteins (P<0.01), and increased the expression levels of LDL-R proteins in the hyperlipidemic rats (P<0.01). These compounds did not significantly influence the expression levels of SREBP-2 and HMGCR proteins in the hyperlipidemic rats.

CONCLUSIONSHdber is effective in the treatment of hyperlipidemia in rats. The therapeutic mechanisms of Hdber may be associated with increasing the expression of LDL-R protein and decreasing the expression of PCSK-9 protein in liver tissues.

Animals ; Apolipoprotein A-I ; blood ; Apolipoproteins B ; blood ; Berberine ; analogs & derivatives ; pharmacology ; therapeutic use ; Hydroxymethylglutaryl CoA Reductases ; metabolism ; Hyperlipidemias ; blood ; drug therapy ; Lipids ; blood ; Liver ; drug effects ; metabolism ; Male ; Proprotein Convertase 9 ; Rats, Wistar ; Receptors, LDL ; metabolism ; Serine Endopeptidases ; metabolism ; Sterol Regulatory Element Binding Protein 2 ; metabolism

OBJECTIVETo express and purify Hap protein of nontypeable Haemophilus influenzae (NTHi) in prokaryotic system, and study its immunogenicity and adhesive activity.

METHODHap protein was expressed in E.coli BL21 with pET32a (+)-Hap and purified by affinity chromatography. The adhesive activity of the recombinant Hap protein was observed in competitive adhesion assay using scanning electron microscope and bacterial counting. BALB/C mice were immunized intranasally with the purified recombinant Hap protein and cholera toxin B subunit (CT-B), and anti-Hap IgA and IgG were detected by enzyme-linked immunosorbent assay.

RESULTSSDS-PAGE analysis showed a single band of the target protein, whose purity reached 85% according to the result of Gel analysis software. The concentration of the protein was 3.2 g/L after ultrafiltration and condensation. Competitive adhesion assay showed that compared with control group, the recombinant Hap protein significantly inhibited the adhesion of NTHi to ECM (P<0.01). Compared with Hap immunization alone, immunization with Hap combined with CT-B resulted in significantly higher titers of anti-Hap IgG and IgA in mice (P<0.05).

CONCLUSIONHighly purified recombinant Hap protein has been obtained in a prokaryotic system and shows good immunogenic and adhesive activities. These results will establish the basis for further study of NTHi vaccine.

Adhesiveness ; Animals ; Bacterial Outer Membrane Proteins ; biosynthesis ; genetics ; immunology ; Cholera Toxin ; immunology ; Escherichia coli ; genetics ; metabolism ; Haemophilus Infections ; prevention & control ; Haemophilus influenzae ; metabolism ; Immunization ; Immunoglobulin A ; blood ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Serine Endopeptidases ; biosynthesis ; genetics ; immunology

Mucosal mast cell-derived chondroitin sulphates (sulphated proteoglycans) were assayed in gut washings and homogenate of FcRgamma-knockout (KO) and wild-type (WT) C57BL/6 mice challenged with Strongyloides venezuelensis in order to assess their possible role in secondary immunity against enteric nematodes. Groups of immune KO and WT mice were challenged by oral gavage with 300 infective larvae (L3). Establishment of infection was assessed by daily faecal analysis to determine the number of eggs per gram of faeces (EPG) and by adult worm recovery on days 5 and 13 post challenge. Mucosal mast cell (MMC) counts were done on days 5 and 13 post challenge while MMC-derived chondroitin sulphates in gut washings (days 1 and 5) and homogenate (day 8) were assayed by high performance liquid chromatography (HPLC). Results showed that patent infection occurred in challenged KO but not WT mice despite significantly higher mastocytosis in jejunal sections of KO than WT mice (p<0.001). Similarly but against prediction, significantly higher concentration of MMC-derived chondroitin sulphates was observed in gut homogenate of KO than WT mice (p<0.05). In contrast, significantly higher concentration of chondroitin sulphates was observed in gut washings of WT than KO mice (p<0.05). These results suggest that MMC in KO mice failed to release sufficient amount of sulphated proteoglycans into the gut lumen as did the WT mice, which may have been part of the hostile environment that prevented the establishment in and eventual expulsion of adult S. venezuelensis from the gut of WT mice following challenge.
Animals ; Cell Count/veterinary ; Chondroitin Sulfates/*immunology/metabolism ; Chymases ; Feces/parasitology ; Intestinal Diseases, Parasitic/immunology/*veterinary ; Intestinal Mucosa/cytology/immunology/parasitology ; Jejunum/cytology/immunology/parasitology ; Male ; Mast Cells/immunology/metabolism/*parasitology ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Parasite Egg Count/veterinary ; Receptors, IgG/*immunology ; Serine Endopeptidases/blood/immunology ; Specific Pathogen-Free Organisms ; Strongyloides/*immunology ; Strongyloidiasis/immunology/parasitology/*veterinary