Encapsulated, genetically engineered cells, secreting glucagon-like peptide-1 for the treatment of non-insulin-dependent diabetes mellitus.

Non-insulin-dependent, or type II, diabetes mellitus is characterized by a progressive impairment of glucose-induced insulin secretion by pancreatic beta cells and by a relative decreased sensitivity of target tissues to the action of this hormone. About one third of type II diabetic patients are treated with oral hypoglycemic agents to stimulate insulin secretion. These drugs however risk inducing hypoglycemia and, over time, lose their efficacy. An alternative treatment is the use of glucagon-like peptide-1 (GLP-1), a gut peptidic hormone with a strong insulinotropic activity. Its activity depends of the presence of normal blood glucose concentrations and therefore does not risk inducing hypoglycemia. GLP-1 can correct hyperglycemia in diabetic patients, even in those no longer responding to hypoglycemic agents. Because it is a peptide, GLP-1 must be administered by injection; this may prevent its wide therapeutic use. Here we propose to use cell lines genetically engineered to secrete a mutant form of GLP-1 which has a longer half-life in vivo but which is as potent as the wild-type peptide. The genetically engineered cells are then encapsulated in semi-permeable hollow fibers for implantation in diabetic hosts for constant, long-term, in situ delivery of the peptide. This approach may be a novel therapy for type II diabetes.

A downstream mediator in the growth repression limb of the jasmonate pathway.

Wounding plant tissues initiates large-scale changes in transcription coupled to growth arrest, allowing resource diversion for defense. These processes are mediated in large part by the potent lipid regulator jasmonic acid (JA). Genes selected from a list of wound-inducible transcripts regulated by the jasmonate pathway were overexpressed in Arabidopsis thaliana, and the transgenic plants were then assayed for sensitivity to methyl jasmonate (MeJA). When grown in the presence of MeJA, the roots of plants overexpressing a gene of unknown function were longer than those of wild-type plants. When transcript levels for this gene, which we named JASMONATE-ASSOCIATED1 (JAS1), were reduced by RNA interference, the plants showed increased sensitivity to MeJA and growth was inhibited. These gain- and loss-of-function assays suggest that this gene acts as a repressor of JA-inhibited growth. An alternative transcript from the gene encoding a second protein isoform with a longer C terminus failed to repress jasmonate sensitivity. This identified a conserved C-terminal sequence in JAS1 and related genes, all of which also contain Zim motifs and many of which are jasmonate-regulated. Both forms of JAS1 were found to localize to the nucleus in transient expression assays. Physiological tests of growth responses after wounding were consistent with the fact that JAS1 is a repressor of JA-regulated growth retardation.

A genetic basis for functional hypothalamic amenorrhea.

Background: Functional hypothalamic amenorrhea is a reversible form of gonadotropin-releasing hormone (GnRH) deficiency commonly triggered by stressors such as excessive exercise, nutritional deficits, or psychological distress. Women vary in their susceptibility to inhibition of the reproductive axis by such stressors, but it is unknown whether this variability reflects a genetic predisposition to hypothalamic amenorrhea. We hypothesized that mutations in genes involved in idiopathic hypogonadotropic hypogonadism, a congenital form of GnRH deficiency, are associated with hypothalamic amenorrhea. Methods: We analyzed the coding sequence of genes associated with idiopathic hypogonadotropic hypogonadism in 55 women with hypothalamic amenorrhea and performed in vitro studies of the identified mutations. Results: Six heterozygous mutations were identified in 7 of the 55 patients with hypothalamic amenorrhea: two variants in the fibroblast growth factor receptor 1 gene FGFR1 (G260E and R756H), two in the prokineticin receptor 2 gene PROKR2 (R85H and L173R), one in the GnRH receptor gene GNRHR (R262Q), and one in the Kallmann syndrome 1 sequence gene KAL1 (V371I). No mutations were found in a cohort of 422 controls with normal menstrual cycles. In vitro studies showed that FGFR1 G260E, FGFR1 R756H, and PROKR2 R85H are loss-of-function mutations, as has been previously shown for PROKR2 L173R and GNRHR R262Q. Conclusions: Rare variants in genes associated with idiopathic hypogonadotropic hypogonadism are found in women with hypothalamic amenorrhea, suggesting that these mutations may contribute to the variable susceptibility of women to the functional changes in GnRH secretion that characterize hypothalamic amenorrhea. Our observations provide evidence for the role of rare variants in common multifactorial disease. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others; ClinicalTrials.gov number, NCT00494169.)

MGMT methylation status: the advent of stratified therapy in glioblastoma?

Glioblastomas are the most malignant gliomas with median survival times of only 15 months despite modern therapies. All standard treatments are palliative. Pathogenetic factors are diverse, hence, stratified treatment plans are warranted considering the molecular heterogeneity among these tumors. However, most patients are treated with "one fits all" standard therapies, many of them with minor response and major toxicities. The integration of clinical and molecular information, now becoming available using new tools such as gene arrays, proteomics, and molecular imaging, will take us to an era where more targeted and effective treatments may be implemented. A first step towards the design of such therapies is the identification of relevant molecular mechanisms driving the aggressive biological behavior of glioblastoma. The accumulation of diverse aberrations in regulatory processes enables tumor cells to bypass the effects of most classical therapies available. Molecular alterations underlying such mechanisms comprise aberrations on the genetic level, such as point mutations of distinct genes, or amplifications and deletions, while others result from epigenetic modifications such as aberrant methylation of CpG islands in the regulatory sequence of genes. Epigenetic silencing of the MGMT gene encoding a DNA repair enzyme was recently found to be of predictive value in a randomized clinical trial for newly diagnosed glioblastoma testing the addition of the alkylating agent temozolomide to standard radiotherapy. Determination of the methylation status of the MGMT promoter may become the first molecular diagnostic tool to identify patients most likely to respond that will allow individually tailored therapy in glioblastoma. To date, the test for the MGMT-methylation status is the only tool available that may direct the choice for alkylating agents in glioblastoma patients, but many others may hopefully become part of an arsenal to stratify patients to respective targeted therapies within the next years.

Silencing of both beta-TrCP1 and HOS (beta-TrCP2) is required to suppress human immunodeficiency virus type 1 Vpu-mediated CD4 down-modulation.

The human immunodeficiency virus type 1 (HIV-1) Vpu protein interacts with CD4 within the endoplasmic reticula of infected cells and targets CD4 for degradation through interaction with beta-TrCP1. Mammals possess a homologue of beta-TrCP1, HOS, which is also named beta-TrCP2. We show by coimmunoprecipitation experiments that beta-TrCP2 binds Vpu and is able to induce CD4 down-modulation as efficiently as beta-TrCP1. In two different cell lines, HeLa CD4+ and Jurkat, Vpu-mediated CD4 down-modulation could not be reversed through the individual silencing of endogenous beta-TrCP1 or beta-TrCP2 but instead required the two genes to be silenced simultaneously.

Protective role of early aquaporin 4 induction against postischemic edema formation.

Aquaporin 4 (AQP4) is a water channel involved in water movements across the cell membrane and is spatially organized on the cell surface in orthogonal array particles (OAPs). Its role in edema formation or resolution after stroke onset has been studied mainly at late time points. We have shown recently that its expression is rapidly induced after ischemia coinciding in time with an early swelling of the ischemic hemisphere. There are two isoforms of AQP4: AQP4-M1 and AQP4-M23. The ratio of these isoforms influences the size of the OAPs but the functional impact is not known. The role of the early induction of AQP4 is not yet known. Thrombin preconditioning in mice provides a useful model to study endogenous protective mechanisms. Using this model, we provide evidence for the first time that the early induction of AQP4 may contribute to limit the formation of edema and that the AQP4-M1 isoform is predominantly induced in the ischemic tissue at this time point. Although it prevents edema formation, the early induction of the AQP4 expression does not prevent the blood-brain barrier disruption, suggesting an effect limited to the prevention of edema formation possibly by removing of water from the tissue.

Poxvirus vector-based HIV vaccines.

PURPOSE OF REVIEW: In this review, we will provide the scientific rationale for the use of poxvirus vectors in the field of HIV vaccines, the immunological profile of the vaccine-induced immune responses, an update on the current use of poxvirus vector-based vaccines in HIV vaccine clinical trials, and the development of new modified poxvirus vectors with improved immunological profile. RECENT FINDINGS: An Ad5-HIV vaccine was tested in a phase IIb clinical trial (known as the Step trial). Vaccinations in the Step trial were discontinued because the vaccine did not show any effect on acquisition of infection and on viral load. After the disappointing failure of the Step trial, the field of HIV vaccine has regained enthusiasm and vigour due to the promising protective effect observed in the phase III efficacy trial (known as RV-144) performed in Thailand which has tested a poxvirus-gp120 combination. SUMMARY: The RV-144 phase III has provided for the first time evidence that an HIV vaccine can prevent HIV infection. The results from the RV-144 trial are providing the scientific rationale for the future development of the HIV vaccine field and for designing future efficacy trials.

Expression of genes encoding the pre-TCR and CD3 complex during thymus development.

The mature TCR is composed of a clonotypic heterodimer (alpha beta or gamma delta) associated with the invariant CD3 components (gamma, delta, epsilon and zeta). There is now considerable evidence that more immature forms of the TCR-CD3 complex (consisting of either CD3 alone or CD3 associated with a heterodimer of TCR beta and pre-T alpha) can be expressed at the cell surface on early thymocytes. These pre-TCR complexes are believed to be necessary for the ordered progression of early T cell development. We have analyzed in detail the expression of both the pre-TCR and CD3 complex at various stages of adult thymus development. Our data indicate that all CD3 components are already expressed at the mRNA level by the earliest identifiable (CD4lo) thymic precursor. In contrast, genes encoding the pre-TCR complex (pre-T alpha and fully rearranged TCR beta) are first expressed at the CD44loCD25+CD4-CD8- stage. Detectable surface expression of both CD3 and TCR beta are delayed relative to expression of the corresponding genes, suggesting the existence of other (as yet unidentified) components of the pre-TCR complex.

The α1-adrenergic receptors: diversity of signaling networks and regulation.

The α(1)-adrenergic receptor (AR) subtypes (α(1a), α(1b), and α(1d)) mediate several physiological effects of epinephrine and norepinephrine. Despite several studies in recombinant systems and insight from genetically modified mice, our understanding of the physiological relevance and specificity of the α(1)-AR subtypes is still limited. Constitutive activity and receptor oligomerization have emerged as potential features regulating receptor function. Another recent paradigm is that β arrestins and G protein-coupled receptors themselves can act as scaffolds binding a variety of proteins and this can result in growing complexity of the receptor-mediated cellular effects. The aim of this review is to summarize our current knowledge on some recently identified functional paradigms and signaling networks that might help to elucidate the functional diversity of the α(1)-AR subtypes in various organs.

Small GTPase RhoE/Rnd3 is a critical regulator of Notch1 signaling.

Aberrations of Notch signaling have been implicated in a variety of human cancers. Oncogenic mutations in NOTCH1 are common in human T-cell leukemia and lymphomas. However, loss-of-function somatic mutations in NOTCH1 arising in solid tumors imply a tumor suppressor function, which highlights the need to understand Notch signaling more completely. Here, we describe the small GTPase RhoE/Rnd3 as a downstream mediator of Notch signaling in squamous cell carcinomas (SCC) that arise in skin epithelia. RhoE is a transcriptional target of activated Notch1, which is attenuated broadly in SCC cells. RhoE depletion suppresses Notch1-mediated signaling in vitro, rendering primary keratinocytes resistant to Notch1-mediated differentiation and thereby favoring a proliferative cell fate. Mechanistic investigations indicated that RhoE controls a key step in Notch1 signaling by mediating nuclear translocation of the activated portion of Notch1 (N1IC) through interaction with importins. Our results define RhoE as a Notch1 target that is essential for recruitment of N1IC to the promoters of Notch1 target genes, establishing a regulatory feedback loop in Notch1 signaling. This molecular circuitry may inform distinct cell fate decisions to Notch1 in epithelial tissues, where carcinomas such as SCC arise. Cancer Res; 74(7); 2082-93. ©2014 AACR.

Differential neuroglycan C expression during retinal degeneration in Rpe65-/- mice.

PURPOSE: An increased mRNA expression of the genes coding for the extracellular matrix proteins neuroglycan C (NGC), interphotoreceptor matrix proteoglycan 2 (IMPG2), and CD44 antigen (CD44) has been observed during retinal degeneration in mice with a targeted disruption of the Rpe65 gene (Rpe65-/- mouse). To validate these data, we analyzed this differential expression in more detail by characterizing retinal NGC mRNA isoform and protein expression during disease progression. METHODS: Retinas from C57/Bl6 wild-type and Rpe65-/- mice, ranging 2 to 18 months of age, were used. NGC, IMPG2, and CD44 mRNA expression was assessed by oligonucleotide microarray, quantitative PCR, and in situ hybridization. Retinal NGC protein expression was analyzed by western blot and immunohistochemistry. RESULTS: As measured by quantitative PCR, mRNA expression of NGC and CD44 was induced by about 2 fold to 3 fold at all time points in Rpe65-/- retinas, whereas initially 4 fold elevated IMPG2 mRNA levels progressively declined. NGC and IMPG2 mRNAs were expressed in the ganglion cell layer, the inner nuclear layer, and at the outer limiting membrane. NGC mRNA was also detected in retinal pigment epithelium cells (RPE), where its mRNA expression was not induced during retinal degeneration. NGC-I was the major isoform detected in the retina and the RPE, whereas NGC-III was barely detected and NGC-II could not be assessed. NGC protein expression was at its highest levels on the apical membrane of the RPE. NGC protein levels were induced in retinas from 2- and 4-month-old Rpe65-/- mice, and an increased amount of the activity-cleaved NGC ectodomain containing an epidermal growth factor (EGF)-like domain was detected. CONCLUSIONS: During retinal degeneration in Rpe65-/- mice, NGC expression is induced in the neural retina, but not in the RPE, where NGC is expressed at highest levels.

Transcription factor PROX1 induces colon cancer progression by promoting the transition from benign to highly dysplastic phenotype.

The Drosophila transcription factor Prospero functions as a tumor suppressor, and it has been suggested that the human counterpart of Prospero, PROX1, acts similarly in human cancers. However, we show here that PROX1 promotes dysplasia in colonic adenomas and colorectal cancer progression. PROX1 expression marks the transition from benign colon adenoma to carcinoma in situ, and its loss inhibits growth of human colorectal tumor xenografts and intestinal adenomas in Apc(min/+) mice, while its transgenic overexpression promotes colorectal tumorigenesis. Furthermore, in intestinal tumors PROX1 is a direct and dose-dependent target of the beta-catenin/TCF signaling pathway, responsible for the neoplastic transformation. Our data underscore the complexity of cancer pathogenesis and implicate PROX1 in malignant tumor progression through the regulation of cell polarity and adhesion.

International Union of Pharmacology. LXI. Peroxisome proliferator-activated receptors.

The three peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors of the nuclear hormone receptor superfamily. They share a high degree of structural homology with all members of the superfamily, particularly in the DNA-binding domain and ligand- and cofactor-binding domain. Many cellular and systemic roles have been attributed to these receptors, reaching far beyond the stimulation of peroxisome proliferation in rodents after which they were initially named. PPARs exhibit broad, isotype-specific tissue expression patterns. PPARalpha is expressed at high levels in organs with significant catabolism of fatty acids. PPARbeta/delta has the broadest expression pattern, and the levels of expression in certain tissues depend on the extent of cell proliferation and differentiation. PPARgamma is expressed as two isoforms, of which PPARgamma2 is found at high levels in the adipose tissues, whereas PPARgamma1 has a broader expression pattern. Transcriptional regulation by PPARs requires heterodimerization with the retinoid X receptor (RXR). When activated by a ligand, the dimer modulates transcription via binding to a specific DNA sequence element called a peroxisome proliferator response element (PPRE) in the promoter region of target genes. A wide variety of natural or synthetic compounds was identified as PPAR ligands. Among the synthetic ligands, the lipid-lowering drugs, fibrates, and the insulin sensitizers, thiazolidinediones, are PPARalpha and PPARgamma agonists, respectively, which underscores the important role of PPARs as therapeutic targets. Transcriptional control by PPAR/RXR heterodimers also requires interaction with coregulator complexes. Thus, selective action of PPARs in vivo results from the interplay at a given time point between expression levels of each of the three PPAR and RXR isotypes, affinity for a specific promoter PPRE, and ligand and cofactor availabilities.

Mice transgenic for BAFF develop lymphocytic disorders along with autoimmune manifestations.

The cause of many autoimmune and inflammatory diseases is unresolved, although dysregulated production of tumor necrosis factor (TNF) family members appears to be important in many cases. BAFF, a new member of the TNF family, binds to B cells and costimulates their growth in vitro. Mice transgenic for BAFF have vastly increased numbers of mature B and effector T cells, and develop autoimmune-like manifestations such as the presence of high levels of rheumatoid factors, circulating immune complexes, anti-DNA autoantibodies, and immunoglobulin deposition in the kidneys. This phenotype is reminiscent of certain human autoimmune disorders and suggests that dysregulation of BAFF expression may be a critical element in the chain of events leading to autoimmunity.

The knock-out of ARP3a gene affects F-actin cytoskeleton organization altering cellular tip growth, morphology and development in moss Physcomitrella patens.

The seven subunit Arp2/3 complex is a highly conserved nucleation factor of actin microfilaments. We have isolated the genomic sequence encoding a putative Arp3a protein of the moss Physcomitrella patens. The disruption of this ARP3A gene by allele replacement has generated loss-of-function mutants displaying a complex developmental phenotype. The loss-of function of ARP3A gene results in shortened, almost cubic chloronemal cells displaying affected tip growth and lacking differentiation to caulonemal cells. In moss arp3a mutants, buds differentiate directly from chloronemata to form stunted leafy shoots having differentiated leaves similar to wild type. Yet, rhizoids never differentiate from stem epidermal cells. To characterize the F-actin organization in the arp3a-mutated cells, we disrupted ARP3A gene in the previously described HGT1 strain expressing conditionally the GFP-talin marker. In vivo observation of the F-actin cytoskeleton during P. patens development demonstrated that loss-of-function of Arp3a is associated with the disappearance of specific F-actin cortical structures associated with the establishment of localized cellular growth domains. Finally, we show that constitutive expression of the P. patens Arp3a and its Arabidopsis thaliana orthologs efficiently complement the mutated phenotype indicating a high degree of evolutionary conservation of the Arp3 function in land plants.