Bifunctional μ/δ opioid peptides: variation of the type and length of the linker connecting the two components.

On the basis of evidence that opioid compounds with a mixed μ agonist/δ antagonist profile may produce an antinociceptive effect with low propensity to induce side effects, bifunctional opioid peptides containing the μ agonist H-Dmt-d-Arg-Phe-Lys-NH(2) ([Dmt(1) ]DALDA; Dmt = 2',6'-dimethyltyrosine) connected tail-to-tail via various α,ω-diaminoalkyl- or diaminocyclohexane linkers to the δ antagonists H-Tyr-TicΨ[CH(2) -NH]Cha-Phe-OH (TICP[Ψ]; Cha = cyclohexylalanine, Tic = 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid), H-Dmt-Tic-OH or H-Bcp-Tic-OH (Bcp = 4'-[N-((4'-phenyl)phenethyl)carboxamido]phenylalanine) were synthesized and pharmacologically characterized in vitro. Bifunctional [Dmt(1) ]DALDA→NH-(CH(2) )(n) -NH←TICP[Ψ] compounds (n = -12) showed decreasing μ and δ receptor binding affinities with increasing linker length. As expected, several of the bifunctional peptides were μ agonist/δ antagonists with low nanomolar μ and δ receptor binding affinities.

Pleiotropic effects of pitavastatin.

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are established first line treatments for hypercholesterolaemia. In addition to the direct effects of statins in reducing concentrations of atherogenic low density lipoprotein cholesterol (LDL-C), several studies have indicated that the beneficial effects of statins may be due to some of their cholesterol-independent, multiple (pleiotropic) effects which may differ between different members of the class. Pitavastatin is a novel synthetic lipophilic statin that has a number of pharmacodynamic and pharmacokinetic properties distinct from those of other statins, which may underlie its potential pleiotropic benefits in reducing cardiovascular risk factors.

A novel mouse model of Alzheimer's disease with chronic estrogen deficiency leads to glial cell activation and hypertrophy.

The role of estrogens in Alzheimer's disease (AD) involving β-amyloid (Aβ) generation and plaque formation was mostly tested in ovariectomized mice with or without APP mutations. The aim of the present study was to explore the abnormalities of neural cells in a novel mouse model of AD with chronic estrogen deficiency. These chimeric mice exhibit a total FSH-R knockout (FORKO) and carry two transgenes, one expressing the β-amyloid precursor protein (APPsw, Swedish mutation) and the other expressing presenilin-1 lacking exon 9 (PS1Δ9).

No detectable XMRV in subjects with chronic fatigue syndrome from Quebec.

We investigated the presence of XMRV in a cohort of Quebec patients with chronic fatigue syndrome (CFS). DNA was purified from activated peripheral blood mononuclear cells (PBMCs) and PCR was used to detect XMRV gag and env in 72 patients. Anti-XMRV antibodies were searched in sera of 62 patients by Western blot analysis.

Cationic polymer based nanocarriers for delivery of therapeutic nucleic acids.

The design and development of nucleic acids based therapeutics for the treatment of diseases arising from genetic abnormalities has made significant progress over the past few years. Advances in synthetic oligonucleotide chemistry resulted in synthesis of nucleic acids that are relatively stable in in vivo environments. However, cellular targeting and intracellular delivery of nucleic acids still remains a challenge.

The proprotein convertases, 20 years later.

The proprotein convertases (PCs) are secretory mammalian serine proteinases related to bacterial subtilisin-like enzymes. The family of PCs comprises nine members, PC1/3, PC2, furin, PC4, PC5/6, PACE4, PC7, SKI-1/S1P, and PCSK9 (Fig. 3.

Strategies and advances in nanomedicine for targeted siRNA delivery.

siRNA are a rapidly emerging class of new therapeutic molecules for the treatment of inherited and acquired diseases. However, poor cellular uptake and instability in physiological conditions limits its therapeutic potential, hence a need to develop a delivery system that can protect and efficiently transport siRNA to the target cells has arisen. Nanoparticles have been proposed as suitable delivery vectors with reduced cytotoxicity and enhanced efficacy.

Latent transforming growth factor beta-binding proteins-2 and -3 inhibit the proprotein convertase 5/6A.

The basic amino acid-specific proprotein convertase 5/6 (PC5/6) is an essential secretory protease, as knock-out mice die at birth and exhibit multiple homeotic transformation defects, including impaired bone morphogenesis and lung structure. Some of the observed defects were attributed to impaired processing of the TGFβ-like growth differentiating factor 11 precursor (proGdf11). In this work we present evidence that the latent TGFβ-binding proteins 2 and 3 (LTBP-2 and -3) inhibit the extracellular processing of proGdf11 by PC5/6A.

Novel hormone-regulated genes in visceral adipose tissue: cloning and identification of proinflammatory cytokine-like mouse and human MEDA-7: implications for obesity, insulin resistance and the metabolic syndrome.

Aims/hypothesis: We sought to characterise novel genes dysregulated by sex hormonal imbalances that induce obesity and metabolic disorder in a setting of oestrogen deficiency and androgen dominance in follicle-stimulating hormone receptor (For [also known as Fshr]) knockout female mice.

Methods: Transcriptome analysis of mesenteric adipose tissue (MAT) of mutants revealed novel genes. One novel gene named Meda-7 was selected for study.

Furin is the major processing enzyme of the cardiac-specific growth factor bone morphogenetic protein 10.

Bone morphogenetic protein 10 (BMP10) is a member of the TGF-β superfamily and plays a critical role in heart development. In the postnatal heart, BMP10 is restricted to the right atrium. The inactive pro-BMP10 (∼60 kDa) is processed into active BMP10 (∼14 kDa) by an unknown protease.

PCSK9 reduces the protein levels of the LDL receptor in mouse brain during development and after ischemic stroke.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a major role in cholesterol homeostasis through enhanced degradation of the LDL receptor (LDLR) in liver. As novel inhibitors/silencers of PCSK9 are now being tested in clinical trials to treat hypercholesterolemia, it is crucial to define the physiological consequences of the lack of PCSK9 in various organs. LDLR regulation by PCSK9 has not been extensively described during mouse brain development and injury.

Role of CD3ε-mediated signaling in T-cell development and function.

Receptor-mediated signal transduction plays an important role in T-cell differentiation and function. The pre-T-cell receptor (pre-TCR) and TCR complexes are the most critical receptors for T-cell biology. Signals induced by pre-TCR and TCR in a ligand-independent or a ligand-dependent manner, respectively, are essential for thymocyte maturation.

What lies ahead for the proprotein convertases?

Limited proteolysis of secretory proteins is performed by one or more of the nine-membered proprotein convertase (PC) family: PC1/3, PC2, furin, PC4, PC5/6, PACE4, PC7, SKI-1/S1P, and PCSK9. The first seven proteinases cleave proproteins at single or pairs of basic residues in the Golgi, secretory granules, cell surface, or endosomes. These comprise neural and endocrine hormones and their release/inhibiting factors, growth factors and their receptors, and adhesion molecules.

Anti-proliferative and pro-apoptotic actions of a novel human and mouse ovarian tumor-associated gene OTAG-12: downregulation, alternative splicing and drug sensitization.

In studying the age dependence and chronology of ovarian tumors in follicle stimulating hormone receptor knockout mice, we identified a novel ovarian tumor associated gene-12 (OTAG-12), which is progressively downregulated and maps to Chr. 8B3.3.

Proprotein convertase PC7 enhances the activation of the EGF receptor pathway through processing of the EGF precursor.

Although the processing profile of the membrane-bound epidermal growth factor precursor (pro-EGF) is tissue-specific, it has not been investigated at the cellular level nor have the cognate proteinases been defined. Among the proprotein convertases (PCs), only the membrane-bound PC7, the most ancient and conserved basic amino acid-specific PC family member, induces the processing of pro-EGF into an ∼115-kDa transmembrane form (EGF-115) at an unusual VHPR(290)↓A motif. Because site-directed mutagenesis revealed that Arg(290) is not critical, the generation of EGF-115 by PC7 is likely indirect.

In vivo evidence that furin from hepatocytes inactivates PCSK9.

The proprotein convertase PCSK9 plays a key role in cholesterol homeostasis by binding the LDL receptor and targeting it toward degradation. PCSK9 is strongly expressed in the liver and is found in human and mouse plasma as mature (∼ 62 kDa) and inactivated (∼ 55 kDa) forms. Ex vivo data showed that human PCSK9 is inactivated by cleavage at Arg(218)↓ by the overexpressed convertases furin and PC5/6A.

The proprotein convertase PC7: unique zymogen activation and trafficking pathways.

The zymogen activation mechanism and physiological functions of the most ancient and highly conserved basic amino acid-specific proprotein convertase 7 (PC7) are not known. Herein, we characterized the biosynthesis, subcellular localization, and trafficking of the membrane-bound full-length rat and human PC7. The prosegment of PC7 is primarily secreted alone as a non-inhibitory protein via the conventional, Golgi-dependent, secretory pathway.

Effects of the prosegment and pH on the activity of PCSK9: evidence for additional processing events.

PCSK9, a target for the treatment of dyslipidemia, enhances the degradation of the LDL receptor (LDLR) in endosomes/lysosomes, up-regulating LDL-cholesterol levels. Whereas the targeting and degradation of the PCSK9-LDLR complex are under scrutiny, the roles of the N- and C-terminal domains of PCSK9 are unknown. Although autocatalytic zymogen processing of PCSK9 occurs at Gln(152)↓, here we show that human PCSK9 can be further cleaved in its N-terminal prosegment at Arg(46)↓ by an endogenous enzyme of insect High Five cells and by a cellular mammalian protease, yielding an ∼4-fold enhanced activity.

HIV-1 Nef disrupts maturation of CD4+ T cells through CD4/Lck modulation.

The HIV-1 Nef protein is a major determinant of HIV-1 pathogenicity. It has been found to induce thymocyte depletion, but the mechanisms involved are not completely understood. Also, nothing is known about its effects on thymocyte selection.

The phosphatase PTP-PEST promotes secondary T cell responses by dephosphorylating the protein tyrosine kinase Pyk2.

PTP-PEST (encoded by Ptpn12) is an intracellular protein tyrosine phosphatase belonging to the same family as LYP. LYP inhibits secondary T cell responses by suppressing Src family protein tyrosine kinases and is implicated in human autoimmunity. To determine the function of PTP-PEST in T cells, we generated mice with a conditionally deleted allele of Ptpn12.

How do SAP family deficiencies compromise immunity?

The signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) family of adaptors couples SLAM family receptors to activating intracellular signaling pathways that drive immune cell activation or differentiation. In the absence of SAP family adaptors, SLAM family receptors become inhibitory, possibly through coupling to the Src-homology-2-containing phosphatases. This "switch-of-function" of SLAM family receptors provides an explanation for the severe immune dysfunctions observed in humans with X-linked lymphoproliferative disease due to SAP deficiency, as well as in genetically engineered mice that lack SAP family adaptors.

Chronology and complexities of ovarian tumorigenesis in FORKO mice: age-dependent gene alterations and progressive dysregulation of Major Histocompatibility Complex (MHC) Class I and II profiles.

Among gynecologic malignancies ovarian cancer is the deadliest and most difficult to detect at early stages. As ovarian tumors have long latency and are relatively more frequent in postmenopausal women, revealing chronological changes in model systems might help in the discovery of novel molecular targets and diagnostic biomarkers for disease detection and management. Follitropin receptor knockout (FORKO) mice with early and sustained sex steroid hormone disharmony develop various age-dependent ovarian abnormalities including increased incidence ovarian tumors in complete absence of ovulation.

Notch1-induced mammary tumor development is cyclin D1-dependent and correlates with expansion of pre-malignant multipotent duct-limited progenitors.

Members of the Notch family are involved in the development of breast cancer in animal models and in humans. In young transgenic mice, expressing intracellular activated Notch1 (N1(IC)) in mammary cells, we found that CD24(+) CD29(high) progenitor cells had enhanced survival, and were expanded through a cyclin D1-dependent pathway. This expansion positively correlated with the later cyclin D1-dependent formation of basal-like ductal tumors.