C肽、血脂水平与2型糖尿病下肢血管病变的关系

目的探讨2型糖尿病患者下肢血管病变的危险因素。方法应用美国GE公司LOG-IQ700型超声诊断仪,对2型糖尿病患者131例下肢动脉进行检测,将下肢血管病变组74例与非下肢血管病变组54例进行对照,记录患者年龄、病程、空腹及餐后血糖、糖化血红蛋白、血脂、空腹及餐后C肽。结果糖尿病下肢血管病变组患者年龄大、病程长、LDL-C明显升高、空腹及餐后C肽明显降低。结论年龄、病程、高血糖、高血脂、低C肽水平是糖尿病下肢血管病变的危险因素,糖尿病神经病变与大血管病变正相关。     

多糖单克隆抗体的研究进展

介绍了制备多糖抗原的两种方法及影响多糖免疫原性的因素,并综述了检测多糖单抗的酶联免疫吸附测定法的最新进展以及多糖单克隆抗体在菌体亚型分类、抗原表位研究、疾病诊断治疗和多糖药代动力学研究等方面的应用情况。     

Antimicrobial activity of myotoxic phospholipases A2 from crotalid snake venoms and synthetic peptide variants derived from their C-terminal region.

A short peptide derived from the C-terminal region of Bothrops asper myotoxin II, a Lys49 phospholipase A(2) (PLA(2)), was previously found to reproduce the bactericidal activity of its parent molecule. In this study, a panel of eight PLA(2) myotoxins purified from crotalid snake venoms, including both Lys49 and Asp49-type isoforms, were all found to express bactericidal activity, indicating that this may be a common action of the group IIA PLA(2) protein family. A series of 10 synthetic peptide variants, based on the original C-terminal sequence 115-129 of myotoxin II and its triple Tyr-->Trp substituted peptide p115-W3, were characterized. In vitro assays for bactericidal, cytolytic and anti-endotoxic activities of these peptides suggest a general correlation between the number of tryptophan substitutions introduced and microbicidal potency, both against Gram-negative (Salmonella typhimurium) and Gram-positive (Staphylococcus aureus) bacteria. Peptide variants with high bactericidal activity also tended to be more cytolytic towards skeletal muscle C2C12 myoblasts, thus limiting their potential in vivo use. However, the peptide variant pEM-2 (KKWRWWLKALAKK) showed reduced toxicity towards muscle cells, while retaining high bactericidal potency. This peptide also showed the highest endotoxin-neutralizing activity in vitro, and was shown to functionally interact with lipopolysaccharide (LPS) using a chimeric bacteria model. The bactericidal and anti-endotoxic properties of pEM-2, combined with its relatively low toxicity towards eukaryotic cells, highlight it as a promising candidate for further evaluation of its antimicrobial potential in vivo.     

Naja melanoleuca cobra venom contains two forms of complement-depleting factor (CVF)

Two forms of complement-depleting cobra venom factor (CVFm1 and CVFm2), possessing molecular masses of 142.6 kDa (CVFm1) and 143.1 kDa (CVFm2), according to MALDI mass-spectrometry, were isolated from the Naja melanoleuca cobra venom. As shown by polyacrylamide gel electrophoresis in the presence of SDS, both forms similarly to factor from the Naja kaouthia cobra venom (CVFk) consist of three polypeptide chains with molecular masses of about 70, 50, and 30 kDa, the two large subunits being glycosylated. As determined by MALDI mass-spectrometry, 30 kDa subunits of CVFm1 and CVFm2 have considerably different finger-prints of tryptic digests that suggests differences in their amino acid sequences. A study of activity in vivo has shown no significant differences in C3 consumption by CVFm1, CVFm2 and CVFk in mouse blood. However, as shown by an immunoassay method, they differ in their ability to activate the complement system via C3 conversion, the ratio of these activities for CVFm1:CVFm2:CVFk being 2.5:1.6:1. Kinetic studies using a hemolytic test showed that complement depletion by CVFm1 is faster than that by CVFm2. Thus, for the first time the presence in a single venom of two forms of CVF differing by both amino acid sequence and biological activity has been shown.     

Proteomics approach on microcystin binding proteins in mouse liver for investigation of microcystin toxicity.

Microcystins (MC) produced by freshwater cyanobacteria are potent hepatotoxins. MC inhibit protein phosphatases (PP) 1 and 2A. MC and okadaic acid (OA), which is a similar PP inhibitor whereas it has a less affinity to PP1 than PP2A, behave similarly to primary culture hepatocytes, with inducements of phosphorylations of cytoskeleton, morphological changes and apoptosis. Although the distribution of OA in mouse liver was observed immunohistochemically, no OA injury was found. The purpose of this study was therefore to determine why only MC has specific toxicities on the liver. A systematic process of MC affinity chromatography and proteomics, using two-dimensional gel electrophoresis and MALDI-TOFMS, indicated the existence of some MC-binding proteins including the complexes of PP1, PP2A, and PP4 with their own regulatory subunits in mouse liver extracts. The competitive inhibition experiments using affinity chromatography with OA showed that two of the three protein complexes strongly interacted with OA, whereas only the complex of PP1 with the inhibitory subunit NIPP1 did not strongly interacted with OA. These results suggest that the PP1 complex is not related to the common behavior of MC and OA of primary culture hepatocytes, and is related to the specific hepatotoxicities of MC.     

Rapid and efficient identification of cysteine-rich peptides by random screening of a venom gland cDNA library from the hexathelid spider Macrothele gigas.

We identified novel 10 multi-cysteine peptides, namely Magi 7-16, from the spider Macrothele gigas by simple random cDNA screening of the venom gland. Mass analysis of the crude venom detected the mass numbers of the cross-linked forms of all peptides, confirming their presence in the venom. Magi 11, a C-terminus amidated peptide, was chemically synthesized and was indistinguishable from the native peptide proving the feasibility of the method for peptide identification. Moreover, toxicological assays showed diverse lethal or paralytic activities of these peptide toxins on mice and/or insects.     

“Hepatocellular carcinoma: A life-threatening disease”

An estimated rise in liver cancer incidence will increase to 95374 new cases by 2020. Hepatocellular Carcinoma (HCC), the most common primary malignant tumour of the liver, is considered to be the third leading cause of all cancer-related deaths and fifth common cancer worldwide. The reported data shows that the rate of HCC incidence in male population is three to four times higher compared with the female population. In the United States, HCV-induced liver cancer is increasing very fast because of the lack of proper treatment option. There are various treatment strategies available for HCC like liver transplantation, resection, ablation, embolization and chemotherapy still the prognosis is destitute. If the patient is eligible, liver transplantation is the only therapeutic option that may give around 90% survival rate, but the scarcity of liver donor limits its broad applicability. A sudden address is necessary to develop specific drugs, personalized medicine, for HCC.     

Non-Viral Peptide-Based Approaches to Gene Delivery

Abstract

To achieve effective non-viral gene therapy, the control of in vitro and in vivo stability, cellular access, intracellular trafficking and nuclear retention of plasmids must be achieved. Inefficient endosomal release, stability against cytosolic nucleases, cytoplasmic transport and nuclear entry of plasmids are amongst some of the key limiting factors in the use of plasmids for effective gene therapy. Synthetic peptide-based gene delivery systems can be designed for DNA compaction, serum stability, cell-specific targeting, endosomo-lysis, cytoplasmic stability and nuclear transport. The stability of compacted DNA under physiological conditions can be enhanced by the use of hydrophilic polymers, such as polyethylene glycol. The aims of this review are to (i) explore theoretical and experimental aspects of DNA compaction, (ii) describe approaches for stabilizing compacted DNA, (iii) assess techniques used for characterization of compacted DNA, and (iv) review possible use of peptides for efficient gene transfer.     

Activation of natural killer cells by heat shock protein 70

Intracellular heat shock proteins (HSP) function as molecular chaperones, they support folding and transport mechanisms of other proteins under physiological conditions and following physical or chemical stress. More recently, extracellular localized HSP have been found to play key roles in the induction of a cellular immune response. Either they act as carrier molecules for immunogenic peptides that are presented on Antigen Presenting Cells (APC) to cytotoxic T-cells or they themselves act as activatory molecules for the innate immune system. Binding of uncomplexed HSP to HSP-receptors on APC has been found to induce the secretion of inflammatory cytokines. Furthermore, an unusual tumor-selective membrane-localization of non-conserved regions of the 72000Da HSP (Hsp70) has been found to act as a recognition structure for natural killer (NK) cells. In this review the interaction of NK cells with Hsp70 or peptides derived thereof will be eluciated in more detail.     

LT adjuvant modulates epitope specificity and improves the efficacy of murine antibodies elicited by sublingual vaccination with the N-terminal domain of Streptococcus mutans P1

In this study, we evaluated the immunogenicity, protective efficacy and peptide-based immune signatures of antibodies raised in mice after sublingual immunization with a recombinant form of the P1 (aka AgI/II, PAc) adhesin (P1_39-512) of Streptococcus mutans, a major etiological agent of dental caries. Sublingual administration of P1_39-512 in combination with the mucosal adjuvant LTK4R (a derivative of heat-labile LT toxin) induced strong and long-lasting systemic and mucosal immune responses. Incorporation of the adjuvant resulted in an enhancement of the anti-adhesive and anti-colonization activity against S. mutans as evaluated both under in vitro and in vivo conditions. Incorporation of the adjuvant to the vaccine formulation also changed the epitope specificity of the induced antibodies as determined by immunological signatures of sera collected from vaccinated mice. Use of a peptide microarray library led to the identification of peptide targets recognized by antibodies in serum samples with enhanced anti-adhesive effects. Altogether, the results presented herein showed that the sublingual administration of a P1-based subunit vaccine represents a promising approach for the prevention of dental caries caused by S. mutans. In addition, the present study disclosed the role of adjuvants on the epitope specificity and functionality of antibodies raised by subunit vaccines.