No abstract

Exhaustive characterizations of antisera to the structurally related peptides pancreatic polypeptide (PP), neuropeptide Y (NPY), and peptide YY (PYY) enabled us to establish the developmental pattern of these peptides in rat and mouse pancreas. PYY was the earliest detectable peptide and was present in all early appearing endocrine cell types. NPY appeared later and occurred exclusively in a subpopulation of insulin cells, whereas PP cells arose latest. At the earliest stage studied, all endocrine cells stored PYY. Most of these cells also contained glucagon. Subsequently, the endocrine cells comprised glucagon+PYY cells and glucagon+PYY+insulin cells. Later, cells storing either only insulin or insulin+PYY appeared. Quantitations of the relative numbers of these cell populations during development were consistent with a precursor role of triple-positive (insulin+glucagon+PYY) cells. Moreover, bromodeoxyuridine (BrdU) injections at E15.5 showed that a large percentage of triple-positive cells were in S-phase and therefore were actively dividing, whereas almost no pure insulin cells or insulin+PYY cells synthesized DNA at this time. These results suggest that PYY-positive endocrine cells may represent precursors for mature islet cells.

Chronic hepatitis B infection (CHB) is an area of high unmet medical need. Current standard-of-care therapies only rarely lead to a functional cure, defined as durable hepatitis B surface antigen (HBsAg) loss following treatment. The goal for next generation CHB therapies is to achieve a higher rate of functional cure with finite treatment duration. To address this urgent need, we are developing liver-targeted single-stranded oligonucleotide (SSO) therapeutics for CHB based on the locked nucleic acid (LNA) platform. These LNA-SSOs target hepatitis B virus (HBV) transcripts for RNase-H-mediated degradation. Here, we describe a HBV-specific LNA-SSO that effectively reduces intracellular viral mRNAs and viral antigens (HBsAg and HBeAg) over an extended time period in cultured human hepatoma cell lines that were infected with HBV with mean 50% effective concentration (EC50) values ranging from 1.19 to 1.66 μM. To achieve liver-specific targeting and minimize kidney exposure, this LNA-SSO was conjugated to a cluster of three N-acetylgalactosamine (GalNAc) moieties that direct specific binding to the asialoglycoprotein receptor (ASGPR) expressed specifically on the surface of hepatocytes. The GalNAc-conjugated LNA-SSO showed a strikingly higher level of potency when tested in the AAV-HBV mouse model as compared with its non-conjugated counterpart. Remarkably, higher doses of GalNAc-conjugated LNA-SSO resulted in a rapid and long-lasting reduction of HBsAg to below the detection limit for quantification, i.e., by 3 log10 (p < 0.0003). This antiviral effect depended on a close match between the sequences of the LNA-SSO and its HBV target, indicating that the antiviral effect is not due to non-specific oligonucleotide-driven immune activation. These data support the development of LNA-SSO therapeutics for the treatment of CHB infection.

We demonstrate that IL-33, GLP-1R, and CCL20 are deregulated in human IBD, and that prophylactic treatment with 0.6 mg/kg liraglutide improves disease in AdTr colitis. In addition, GLP-1 receptor agonists upregulate IL-33, mucin 5b, and CCL20 in murine Brunner's glands. Taken together, our data indicate that GLP-1 receptor agonists affect gut homeostasis in both proximal and distal parts of the gut.

Growth hormone and prolactin are important growth factors for pancreatic -cells. The effects exerted by these hormones on proliferation and on insulin synthesis and secretion in -cells are largely mediated through the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway. Suppressors of cytokine signaling (SOCS) proteins are specific inhibitors of the JAK/STAT pathway acting through a negative-feedback loop. To investigate in vivo effects of SOCS-3 in growth hormone (GH)/prolactin signaling in -cells we generated transgenic mice with -cell-specific overexpression of SOCS-3. The relative -cell proliferation and volume in the mice were measured by morphometry. -Cell volume of transgenic female mice was reduced by over 30% compared with -cell volume in wild-type female mice. Stimulation of transgenic islets in vitro with GH showed a reduced tyrosine phosphorylation of STAT-5 when compared with wild-type islets. Transduction of primary islet cultures with adenoviruses expressing various SOCS proteins followed by stimulation with GH or glucagon-like peptide-1 (GLP-1) revealed that SOCS-3 inhibited GH-but not GLP-1-mediated islet cell proliferation, indicating that the decreased -cell volume observed in female transgenic mice could be caused by an inhibition of GH-induced -cell proliferation by SOCS-3. In spite of the reduced -cell volume the transgenic female mice exhibited enhanced glucose tolerance compared with wild-type littermates following an oral glucose-tolerance test. Together these data suggest that SOCS-3 modulates cytokine signaling in pancreatic -cells and therefore potentially could be a candidate target for development of new treatment strategies for diabetes.