Native Collagen II Relieves Bone Impairment through Improving Inflammation and Oxidative Stress in Ageing db/db Mice.

Ageing-related bone impairment due to exposure to hyperglycemic environment is scarcely researched. The aim was to confirm the improvement effects of undenatured type II collagen (UC II) on bone impairment in ageing db/db mice, and the ageing model was established by normal feeding for 48-week-old. Then, the ageing db/db mice were randomly assigned to UC II intervention, the ageing model, and the chondroitin sulfate + glucosamine hydrochloride control groups. After 12 weeks of treatment, femoral microarchitecture and biomechanical parameters were observed, biomarkers including bone metabolism, inflammatory cytokines, and oxidative stress were measured, and the gastrocnemius function and expressions of interleukin (IL) 1ß, receptor activator of nuclear factor (NF)-κB ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) were analyzed. The results showed that the mice in the UC II intervention group showed significantly superior bone and gastrocnemius properties than those in the ageing model group, including bone mineral density (287.65 ± 72.77 vs. 186.97 ± 32.2 mg/cm3), gastrocnemius index (0.46 ± 0.07 vs. 0.18 ± 0.01%), muscle fiber diameter (0.0415 ± 0.005 vs. 0.0330 ± 0.002 mm), and cross-sectional area (0.0011 ± 0.00007 vs. 0.00038 ± 0.00004 mm2). The UC II intervention elevated bone mineralization and formation and decreased bone resorption, inflammatory cytokines, and the oxidative stress. In addition, lower protein expression of IL-1ß, RANKL, and TRAP in the UC II intervention group was observed. These findings suggested that UC II improved bones impaired by T2DM during ageing, and the likely mechanism was partly due to inhibition of inflammation and oxidative stress.

Reversal of autoimmunity by mixed chimerism enables reactivation of ß cells and transdifferentiation of α cells in diabetic NOD mice.

Type 1 diabetes (T1D) results from the autoimmune destruction of ß cells, so cure of firmly established T1D requires both reversal of autoimmunity and restoration of ß cells. It is known that ß cell regeneration in nonautoimmune diabetic mice can come from differentiation of progenitors and/or transdifferentiation of α cells. However, the source of ß cell regeneration in autoimmune nonobese diabetic (NOD) mice remains unclear. Here, we show that, after reversal of autoimmunity by induction of haploidentical mixed chimerism, administration of gastrin plus epidermal growth factor augments ß cell regeneration and normalizes blood glucose in the firmly established diabetic NOD mice. Using transgenic NOD mice with inducible lineage-tracing markers for insulin-producing ß cells, Sox9+ ductal progenitors, Nestin+ mesenchymal stem cells, and glucagon-producing α cells, we have found that both reactivation of dysfunctional low-level insulin expression (insulinlo) ß cells and neogenesis contribute to the regeneration, with the latter predominantly coming from transdifferentiation of α cells. These results indicate that, after reversal of autoimmunity, reactivation of ß cells and transdifferentiation of α cells can provide sufficient new functional ß cells to reach euglycemia in firmly established T1D.

Calcium dobesilate reduces VEGF signaling by interfering with heparan sulfate binding site and protects from vascular complications in diabetic mice.

Inhibiting vascular endothelial growth factor (VEGF) is a therapeutic option in diabetic microangiopathy. However, VEGF is needed at physiological concentrations to maintain glomerular integrity; complete VEGF blockade has deleterious effects on glomerular structure and function. Anti-VEGF therapy in diabetes raises the challenge of reducing VEGF-induced pathology without accelerating endothelial cell injury. Heparan sulfate (HS) act as a co-receptor for VEGF. Calcium dobesilate (CaD) is a small molecule with vasoprotective properties that has been used for the treatment of diabetic microangiopathy. Preliminary evidence suggests that CaD interferes with HS binding sites of fibroblast growth factor. We therefore tested the hypotheses that (1) CaD inhibits VEGF signaling in endothelial cells, (2) that this effect is mediated via interference between CaD and HS, and (3) that CaD ameliorates diabetic nephropathy in a streptozotocin-induced diabetic mouse model by VEGF inhibition. We found that CaD significantly inhibited VEGF165-induced endothelial cell migration, proliferation, and permeability. CaD significantly inhibited VEGF165-induced phosphorylation of VEGFR-2 and suppressed the activity of VEGFR-2 mediated signaling cascades. The effects of CaD in vitro were abrogated by heparin, suggesting the involvement of heparin-like domain in the interaction with CaD. In addition, VEGF121, an isoform which does not bind to heparin, was not inhibited by CaD. Using the proximity ligation approach, we detected inhibition of interaction in situ between HS and VEGF and between VEGF and VEGFR-2. Moreover, CaD reduced VEGF signaling in mice diabetic kidneys and ameliorated diabetic nephropathy and neuropathy, suggesting CaD as a VEGF inhibitor without the negative effects of complete VEGF blockade and therefore could be useful as a strategy in treating diabetic nephropathy.

Suppressive effects of the sodium­glucose cotransporter 2 inhibitor tofogliflozin on colorectal tumorigenesis in diabetic and obese mice.

Sodium­glucose cotransporter 2 inhibitors were developed for the treatment of diabetes mellitus. Although recent studies have indicated that sodium­glucose cotransporter 2 inhibitors have suppressive effects on several types of cancer, their effects against colorectal cancer remain unknown. The purpose of the present study was to investigate the effects of tofogliflozin, a sodium­glucose cotransporter 2 inhibitor, on the development of colorectal cancer in diabetic and obese mice. The direct effects of tofogliflozin on the proliferation of colorectal cancer cells were also evaluated. C57BL/KsJ­db/db mice were injected with azoxymethane to induce colorectal pre­malignancy and they received drinking water with or without tofogliflozin. At the end of the study, administration of tofogliflozin was revealed to significantly suppress the development of colorectal neoplastic lesions and ß­catenin accumulated crypts. In the tofogliflozin­treated mice, the levels of blood glucose and serum TNF­α, as well as mRNA expression of the pro­inflammatory markers in the white adipose tissue, were reduced. Furthermore, macrophage infiltrations in the white adipose tissues were also reduced significantly. The proliferation of the sodium­glucose cotransporter 2­expressing human colorectal cancer cells was not altered by tofogliflozin. These results indicated that tofogliflozin ameliorated chronic inflammation and hyperglycemic condition leading to prevention of colorectal tumorigenesis in a diabetes­ and obesity­related colorectal cancer model.

MicroRNA-135a-3p regulates angiogenesis and tissue repair by targeting p38 signaling in endothelial cells.

Angiogenesis is a critical process in repair of tissue injury that is regulated by a delicate balance between pro- and antiangiogenic factors. In disease states associated with impaired angiogenesis, we identified that miR-135a-3p is rapidly induced and serves as an antiangiogenic microRNA (miRNA) by targeting endothelial cell (EC) p38 signaling in vitro and in vivo. MiR-135a-3p overexpression significantly inhibited EC proliferation, migration, and network tube formation in matrigel, whereas miR-135-3p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3'-UTR reporter and miRNA ribonucleoprotein complex -immunoprecipitation assays, and small interfering RNA dependency studies revealed that miR-135a-3p inhibits the p38 signaling pathway in ECs by targeting huntingtin-interacting protein 1 (HIP1). Local delivery of miR-135a-3p inhibitors to wounds of diabetic db/db mice markedly increased angiogenesis, granulation tissue thickness, and wound closure rates, whereas local delivery of miR-135a-3p mimics impaired these effects. Finally, through gain- and loss-of-function studies in human skin organoids as a model of tissue injury, we demonstrated that miR-135a-3p potently modulated p38 signaling and angiogenesis in response to VEGF stimulation by targeting HIP1. These findings establish miR-135a-3p as a pivotal regulator of pathophysiological angiogenesis and tissue repair by targeting a VEGF-HIP1-p38K signaling axis, providing new targets for angiogenic therapy to promote tissue repair.-Icli, B., Wu, W., Ozdemir, D., Li, H., Haemmig, S., Liu, X., Giatsidis, G., Cheng, H. S., Avci, S. N., Kurt, M., Lee, N., Guimaraes, R. B., Manica, A., Marchini, J. F., Rynning, S. E., Risnes, I., Hollan, I., Croce, K., Orgill, D. P., Feinberg, M. W. MicroRNA-135a-3p regulates angiogenesis and tissue repair by targeting p38 signaling in endothelial cells.

[Generation of a new strain of NOD/SCID/IL2Rγ-/- mice with targeted disruption of Prkdc and IL2Rγ genes using CRISPR/Cas9 system].

OBJECTIVE: The NOD/SCID/IL2Rγ- /- (NSG) mouse strain is the most widely used immunodeficient strain for xenograft transplantation. However, the existing SCID mutation is a spontaneous mutation of the Prkdc gene, which leads to leaky T cell developmental block and difficulty in genotyping. It is therefore important to develop a new strain of NSG mice with targeted disruption of Prkdc and IL2Rγ genes. METHODS: Targeted disruption of Prkdc and IL2Rγ genes was achieved using the CRISPR/Cas9 system. By intercrossing the knockout and NOD mice, we obtained a novel strain of NOD/SCID/IL2Rγ- /-(NSG) mice, denoted as cNSG (Chinese NSG) mice. RESULTS: In addition to the NOD mutation, cNSG mice exhibited a complete absence of T cells, B cells and NK cells. cNSG mice allowed more efficient engraftment of human cancer cells than the commonly used immunodeficient nude mice. CONCLUSION: cNSG mice will provide an important xenotransplantation model for biomedical research.

A new genetic tool to improve immune-compromised mouse models: Derivation and CRISPR/Cas9-mediated targeting of NRG embryonic stem cell lines.

Development of human hematopoietic stem cells and differentiation of embryonic stem (ES) cells/induced pluripotent stem (iPS) cells to hematopoietic stem cells are poorly understood. NOD (Non-obese diabetic)-derived mouse strains, such as NSG (NOD-Scid-il2Rg) or NRG (NOD-Rag1-il2Rg), are the best available models for studying the function of fetal and adult human hematopoietic cells as well as ES/iPS cell-derived hematopoietic stem cells. Unfortunately, engraftment of human hematopoietic stem cells is very variable in these models. Introduction of additional permissive mutations into these complex genetic backgrounds of the NRG/NSG mice by natural breeding is a very demanding task in terms of time and resources. Specifically, since the genetic elements defining the NSG/NRG phenotypes have not yet been fully characterized, intense backcrossing is required to ensure transmission of the full phenotype. Here we describe the derivation of embryonic stem cell (ESC) lines from NRG pre-implantation embryos generated by in vitro fertilization followed by the CRISPR/CAS9 targeting of the Gata-2 locus. After injection into morula stage embryos, cells from three tested lines gave rise to chimeric adult mice showing high contribution of the ESCs (70%-100%), assessed by coat color. Moreover, these lines have been successfully targeted using Cas9/CRISPR technology, and the mutant cells have been shown to remain germ line competent. Therefore, these new NRG ESC lines combined with genome editing nucleases bring a powerful genetic tool that facilitates the generation of new NOD-based mouse models with the aim to improve the existing xenograft models.

Liver Kinase B1/AMP-Activated Protein Kinase Pathway Activation Attenuated the Progression of Endotoxemia in the Diabetic Mice.

BACKGROUND/AIMS: Sepsis is a common disease that continues to increase in prevalence worldwide, and diabetes mellitus may make the situation worse. This study was designed to determine the role of Liver Kinase B1 (LKB1)/adenosine monophosphate-activated protein kinase (AMPK) signaling pathway in diabetic mice complicated with systemic endotoxemia. METHODS: The effects of LKB1/AMPK signaling pathway activation on endotoxemia were investigated in streptozotocin induced diabetic mice (STZ-mice) and db/db diabetic mice. Primary peritoneal macrophages and human umbilical vein endothelial cells (HUVECs) monolayers were simultaneously stimulated by both high glucose and LPS and used as a model to investigate the potential molecular mechanisms in vitro. RESULTS: After treatment with LPS, high glucose or both LPS and high glucose, phosphor-AMPK expression was decreased, and moreover, AMPK activation by metformin treatment alleviated the decrease in phosphor-AMPK expression in HUVECs and macrophages as well as in lung tissue. Furthermore, both LPS and high glucose co-treatment decreased LKB1 and phosphor-AMPK expression via enhanced oxidative stress response, and importantly, LKB1 overexpression mediated by adenovirus inhibited the decrease in phosphor-AMPK expression in macrophages and HUVECs. AMPK activation by metformin administration improved the survival of STZ-induced diabetic mice and db/db diabetic mice, which was associated with reduced lung endothelial hyperpermeability and systemic inflammatory response. Furthermore, the permeability of HUVECs monolayers induced by both high glucose and LPS stimulation was also alleviated by AMPK activation, which was partly via suppression of VE-cadherin phosphorylation. CONCLUSION: These data demonstrated that LKB1/AMPK signaling pathway activation improved the survival of diabetic mice complicated with endotoxemia. Thus, LKB1/AMPK signaling pathway may serve as a potentially useful therapeutic target for severe infection in diabetic patients.

Insulina regula a translocação nuclear de NF-κB p65, inflamação e morte celular em modelo experimental de sepse em camundongos diabéticos / Insulin regulates NF-κB p65 nuclear translocation, inflammation and cell death in septic diabetic mice

Sepse é uma resposta sistêmica e deletéria do indivíduo a uma infecção, sendo um importante problema de saúde pública. Pacientes diabéticos são bastante afetados representando cerca de 22% de todos os pacientes sépticos. A suscetibilidade para o desenvolvimento de sepse no diabetes, bem como a ação da insulina em modular alguns parâmetros imunológicos necessitam de maiores esclarecimentos O objetivo deste estudo foi avaliar os efeitos do tratamento com insulina em um modelo murino de diabetes e sepse. Camundongos C57BL/6 foram tornados diabéticos por administração de aloxana. Os seguintes parâmetros foram analisados vinte e quatro horas após a ligadura cecal e punção (CLP): (a) interleukine (IL)-6, IL-10, chemokine (C -C motif) ligand 2 (CCL2) e tumor necrosis fator (TNF ) -α no soro; (b) os níveis de IL-1ß, IL-6, TNF-α, IL-10, chemokine (C -X-C motif) ligand (CXCL)-1 e CXCL2 no lavado peritoneal (LPe) e broncoalveolar (LBA), bem como nos rins e fígado; (c) contagens celulares totais e diferenciais em LPe e LBA; (d) capacidade endocítica de neutrófilos e produção de espécies reactivas de oxigénio (ERO); (e) níveis de apoptose e necrose no baço e níveis relativos de células CD4+ e CD8+; (f) resultados histopatológicos de pulmão, rim e fígado; e (g) níveis de translocação nuclear de NF-κB p65. Camundongos diabéticos-CLP exibiram concentrações séricas aumentadas de TNF-α, IL-6, CCL2, IL-1, IL-6, CXCL1, CXCL2 e IL-10 e contagens de neutrófilos em LPe. A capacidade endocítica dos neutrófilos e a produção de ERO apresentavam-se reduzidas em animais CLP-diabéticos e os níveis de IL-6, TNF-α, CXCL1 e CXCL2 em LBA e IL-1ß, IL-6, CXCL1 e CXCL2 nos homogenados renais aumentaram diabéticos -CLP. O tratamento destes com insulina reduziu os nívies de citocinas séricas, aumentou a concentração de citocinas e a migração celular para o Lpe, restaurou a capacidade endocítica e a produção de ERO e reduziu a translocação nuclear NF-κB p65 no tecido renal. Estes dados sugerem que a insulina modula a produção/libertação de citocinas, regula a migração celular, a apoptose, a necrose e a translocação nuclear de NF-κB p65 na sepse induzida por CLP em camundongos diabéticos.

Sepsis is a systemic and harmful response of the individual to infection and is an important public health problem. Diabetic patients are greatly affected representing about 22% of all septic patients. The susceptibility to sepsis development in diabetic individuals and insulin action in modulating some immunological parameters require further clarification. The aim of this study was to evaluate the effects of insulin treatment in a mouse model of diabetes and sepsis. C57BL/6 mice were rendered diabetic by alloxan administration. The following parameters were analyzed twenty-four hours after a cecal ligation and puncture (CLP): (a) interleukin (IL)-6, IL-10, chemokine (C-C motif) ligand 2 (CCL2), and tumor necrosis factor (TNF) - α levels in serum; (b) IL-1ß, IL-6, TNF-α, IL-10, chemokine (C-X-C motif) ligand (CXCL)1 and CXCL2 levels in peritoneal lavage (PeL) and bronchoalveolar lavage (BAL) fluid, as well as in the kidneys and liver; (c) total and differential cell counts in PeL and BAL fluid; (d) neutrophil endocytic capacity and reactive oxygen species (ROS) production; (e) spleen cell apoptosis and necrosis levels and relative CD4+ and CD8+ T cell levels; (f) lung, kidney, and liver histopathological results; and (g) NF-kB p65 nuclear translocation levels. Diabetic-CLP mice exhibited increased serum TNF-α, IL-6, CCL2, IL-1, IL-6, CXCL1, CXCL2 and IL-10 concentrations and neutrophil counts in PeL fluid. Neutrophil endocytic capacity and ROS production were decreased in diabetic-CLP mice, and IL-6, TNF- α, CXCL1 and CXCL2 leves in BAL fluid and IL-1ß, IL-6, CXCL1 and CXCL2 levels in kidney homogenates were increased in diabetic-CLP mice. Treatment of these mice with insulin reduced serum cytokine levels increased cytokine and cell migration into PeL fluid, and restored neutrophil endocytic capacity and ROS production and NF-kB p65 nuclear translocation in the kidney. These data suggest that insulin modulates cytokine production/release, regulates cellular migration, apoptosis, necrosis and NF-kB p65 nuclear translocation in CLP-induced sepsis in diabetic mice.

NK Cell Proportion and Number Are Influenced by Genetic Loci on Chromosomes 8, 9, and 17.

NK cells play a crucial role in innate immunity due to their direct cytotoxicity toward tumors, virally infected cells, and stressed cells, and they also contribute to the orchestration of the adaptive response by their ability to produce immunoregulatory cytokines. In secondary lymphoid organs, NK cells compose the third most abundant lymphocyte subset after T cells and B cells. In this study, we perform an unbiased linkage analysis to determine the genetic loci that may limit the size of the NK cell compartment. Specifically, we exploit differences in NK cell proportion and absolute number between the C57BL/6 and the NOD mice. In addition to the previously identified linkage to chromosome 8, we find that a locus on chromosome 17, which encompasses the MHC locus, impacts NK cell number. Moreover, we identify a locus on mouse chromosome 9 that is strongly linked to the proportion and absolute number of NK cells. Using NOD congenic mice, we validate that both the MHC and the chromosome 9 loci influence the proportion and absolute number of NK cells. We have thus identified additional loci specifically linked to the proportion of NK cells and present some of the potential candidate genes comprised within these loci.

The complete mitochondrial genome for an autoimmune thyroiditis mouse strain NOD.H-2h4.

Autoimmune thyroiditis is a chronic organ-specific autoimmune disease characterized by mononuclear cell infiltration of the thyroid gland and destruction of thyroid follicles by the infiltrating inflammatory cells. We sequenced the complete mitochondrial genome sequencing of an autoimmune thyroiditis mouse strain NOD.H-2h4 for the first time. The total length of the mitogenome was 16,310 bp and contains 159 SNPs compared with the house mouse reference sequence.

Histidine Decarboxylase Deficiency Prevents Autoimmune Diabetes in NOD Mice.

Recent evidence has highlighted the role of histamine in inflammation. Since this monoamine has also been strongly implicated in the pathogenesis of type-1 diabetes, we assessed its effect in the nonobese diabetic (NOD) mouse model. To this end, we used mice (inactivated) knocked out for the gene encoding histidine decarboxylase, the unique histamine-forming enzyme, backcrossed on a NOD genetic background. We found that the lack of endogenous histamine in NOD HDC(-/-) mice decreased the incidence of diabetes in relation to their wild-type counterpart. Whereas the proportion of regulatory T and myeloid-derived suppressive cells was similar in both strains, histamine deficiency was associated with increased levels of immature macrophages, as compared with wild-type NOD mice. Concerning the cytokine pattern, we found a decrease in circulating IL-12 and IFN-γ in HDC(-/-) mice, while IL-6 or leptin remained unchanged, suggesting that histamine primarily modulates the inflammatory environment. Paradoxically, exogenous histamine given to NOD HDC(-/-) mice provided also protection against T1D. Our study supports the notion that histamine is involved in the pathogenesis of diabetes, thus providing additional evidence for its role in the regulation of the immune response.

Evidence that MHC I-E dampens thyroid autoantibodies and prevents spreading to a second thyroid autoantigen in I-A(k) NOD mice.

NOD.H2(k) and NOD.H2(h4) mice carry the major histocompatibility complex (MHC) class II molecule I-A(k) associated with susceptibility to experimentally induced thyroiditis. Dietary iodine-enhanced spontaneous thyroid autoimmunity, well known in NOD.H2(h4) mice, has not been investigated in NOD.H2(k) mice. We compared NOD.H2(h4) and NOD.H2(k) strains for thyroiditis and autoantibodies to thyroglobulin (TgAb) and thyroid peroxidase (TPOAb) without or with dietary sodium iodide (NaI) for up to 32 weeks. TgAb levels were significantly higher in NOD.H2(h4) compared with NOD.H2(k) mice on NaI, and TPOAb developed in NOD.H2(h4) mice but not in NOD.H2(k) mice. DNA exome analysis revealed, in addition to the differences in the chromosome (Chr) 17 MHC regions, that NOD.H2(k) mice, and particularly NOD.H2(h4) mice, have substantial non-MHC parental DNA. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis highlighted thyroid autoimmunity and immune-response genes on Chr 17 but not on Chr 7, and 15 parental B10.A4R DNA. Studies of parental strains provided no evidence for non-MHC gene contributions. The exon 10 Tg haplotype, associated with experimentally induced thyroiditis, is absent in NOD.H2(h4) and NOD.H2(k) mice and is not a marker for spontaneous murine thyroid autoimmunity. In conclusion, the absence of I-E is a likely explanation for the difference between NOD.H2(h4) and NOD.H2(k) mice in TgAb levels and, as in humans, autoantibody spreading to TPO.

Targeting the splicing of mRNA in autoimmune diseases: BAFF inhibition in Sjögren's syndrome as a proof of concept.

BAFF (B-cell-activating factor of the tumor necrosis factor family), a pivotal cytokine for B-cell activation, is overexpressed by salivary gland (SG) epithelial cells in primary Sjogren's syndrome (pSS). ΔBAFF, a physiological inhibitor of BAFF, is a minor alternative splice variant of BAFF. A U7 RNA was reengineered to deliver antisense sequences targeting BAFF splice regions. A major decrease of BAFF messenger RNA (mRNA) and protein secretion, concomitantly with the increase of ΔBAFF mRNA, was observed in vitro. In vivo, SG retrograd instillation of nonobese diabetic mice by the modified U7 cloned into an adeno-associated virus vector significantly decreased BAFF protein expression and lymphocytic infiltrates and improved salivary flow. This study offers a rationale for localized therapeutic BAFF inhibition in pSS and represents a proof of concept of the interest of exon skipping in autoimmune diseases.

Stimulating ß-cell regeneration by combining a GPR119 agonist with a DPP-IV inhibitor.

BACKGROUND: Activating G-protein coupled receptor 119 (GPR119) by its agonists can stimulate glucagon like peptide-1 (GLP-1) release. GLP-1 is rapidly degraded and inactivated by dipeptidylpeptidase-IV (DPP-IV). We studied the efficiency of combining PSN632408, a GPR119 agonist, with sitagliptin, a DPP-IV inhibitor, on ß-cell regeneration in diabetic mice. MATERIALS & METHODS: Diabetes in C57BL/6 mice was induced by streptozotocin. PSN632408 and sitagliptin alone or in combination were administered to diabetic mice for 7 weeks along with BrdU daily. Nonfasting blood glucose levels were monitored. After treatment, oral glucose tolerance test (OGTT), plasma active GLP-1 levels, ß-cell mass along with α- and ß-cell replication, and ß-cell neogenesis were evaluated. RESULTS: Normoglycemia was not achieved in vehicle-treated mice. By contrast, 32% (6 of 19) of PSN632408-treated diabetic mice, 36% (5 of 14) sitagliptin-treated diabetic mice, and 59% (13 of 22) diabetic mice treated with PSN632408 and sitagliptin combination achieved normoglycemia after 7 weeks treatment. Combination therapy significantly increased plasma active GLP-1 levels, improved glucose clearance, stimulated both α- and ß-cell replication, and augmented ß-cell mass. Furthermore, treatment with combination therapy induced ß-cell neogenesis from pancreatic duct-derived cells. CONCLUSION: Our results demonstrate that combining a GPR119 agonist with a DPP-IV inhibitor may offer a novel therapeutic strategy for stimulating ß-cell regeneration and reversing diabetes.

Deletion of 12/15-lipoxygenase alters macrophage and islet function in NOD-Alox15(null) mice, leading to protection against type 1 diabetes development.

AIMS: Type 1 diabetes (T1D) is characterized by autoimmune depletion of insulin-producing pancreatic beta cells. We showed previously that deletion of the 12/15-lipoxygenase enzyme (12/15-LO, Alox15 gene) in NOD mice leads to nearly 100 percent protection from T1D. In this study, we test the hypothesis that cytokines involved in the IL-12/12/15-LO axis affect both macrophage and islet function, which contributes to the development of T1D. METHODS: 12/15-LO expression was clarified in immune cells by qRT-PCR, and timing of expression was tested in islets using qRT-PCR and Western blotting. Expression of key proinflammatory cytokines and pancreatic transcription factors was studied in NOD and NOD-Alox15(null) macrophages and islets using qRT-PCR. The two mouse strains were also assessed for the ability of splenocytes to transfer diabetes in an adoptive transfer model, and beta cell mass. RESULTS: 12/15-LO is expressed in macrophages, but not B and T cells of NOD mice. In macrophages, 12/15-LO deletion leads to decreased proinflammatory cytokine mRNA and protein levels. Furthermore, splenocytes from NOD-Alox15(null) mice are unable to transfer diabetes in an adoptive transfer model. In islets, expression of 12/15-LO in NOD mice peaks at a crucial time during insulitis development. The absence of 12/15-LO results in maintenance of islet health with respect to measurements of islet-specific transcription factors, markers of islet health, proinflammatory cytokines, and beta cell mass. CONCLUSIONS: These results suggest that 12/15-LO affects islet and macrophage function, causing inflammation, and leading to autoimmunity and reduced beta cell mass.

Toward minimal conditioning protocols for allogeneic chimerism in tolerance resistant recipients.

Mixed chimerism is a promising approach toward generating donor-specific immunological tolerance. However, chimerism induction can be toxic; therefore, there is an effort to develop non-myeloablative, minimal intensity protocols that can generate chimerism without the toxic side effects. Recently, with the goal of creating a minimalistic chimerism induction protocol in the tolerance resistant non-obese diabetic (NOD) mouse model, we identified pre-existing T cells as cells that resist fully allogeneic chimerism. With monoclonals targeting NOD T cells, we showed that long-term chimerism and tolerance toward donor islets could be established. However, this promising new protocol relied on the administration of a single dose of anti-CD40 ligand, which is not clinically applicable. In refining protocols to move even closer to clinical utility, we report here initial success at generating fully allogeneic mixed chimerism in NOD mice by adding cyclophosphamide to the conditioning regimen in place of anti-CD40 ligand antibodies.

Antibody repertoires in humanized NOD-scid-IL2Rγ(null) mice and human B cells reveals human-like diversification and tolerance checkpoints in the mouse.

Immunodeficient mice reconstituted with human hematopoietic stem cells enable the in vivo study of human hematopoiesis. In particular, NOD-scid-IL2Rγ(null) engrafted mice have been shown to have reasonable levels of T and B cell repopulation and can mount T-cell dependent responses; however, antigen-specific B-cell responses in this model are generally poor. We explored whether developmental defects in the immunoglobulin gene repertoire might be partly responsible for the low level of antibody responses in this model. Roche 454 sequencing was used to obtain over 685,000 reads from cDNA encoding immunoglobulin heavy (IGH) and light (IGK and IGL) genes isolated from immature, naïve, or total splenic B cells in engrafted NOD-scid-IL2Rγ(null) mice, and compared with over 940,000 reads from peripheral B cells of two healthy volunteers. We find that while naïve B-cell repertoires in humanized mice are chiefly indistinguishable from those in human blood B cells, and display highly correlated patterns of immunoglobulin gene segment use, the complementarity-determining region H3 (CDR-H3) repertoires are nevertheless extremely diverse and are specific for each individual. Despite this diversity, preferential D(H)-J(H) pairings repeatedly occur within the CDR-H3 interval that are strikingly similar across all repertoires examined, implying a genetic constraint imposed on repertoire generation. Moreover, CDR-H3 length, charged amino-acid content, and hydropathy are indistinguishable between humans and humanized mice, with no evidence of global autoimmune signatures. Importantly, however, a statistically greater usage of the inherently autoreactive IGHV4-34 and IGKV4-1 genes was observed in the newly formed immature B cells relative to naïve B or total splenic B cells in the humanized mice, a finding consistent with the deletion of autoreactive B cells in humans. Overall, our results provide evidence that key features of the primary repertoire are shaped by genetic factors intrinsic to human B cells and are principally unaltered by differences between mouse and human stromal microenvironments.

Distinct role of T helper Type 17 immune response for Graves' hyperthyroidism in mice with different genetic backgrounds.

T helper type 17 (Th17) cells, a newly identified effector T-cell subset, have recently been shown to play a role in numerous autoimmune diseases, including iodine-induced autoimmune thyroiditis in non-obese diabetic (NOD)-H2(h4) mice, which had previously been thought Th1-dominant. We here studied the role of Th17 in Graves' hyperthyroidism, another thyroid-specific autoimmune disease, in a mouse model. Two genetically distinct BALB/c and NOD-H2(h4) strains with intact or disrupted IL-17 genes (IL-17(+/+) or IL-17(-/-)) were immunized with adenovirus (Ad) expressing the thyrotropin receptor (TSHR) A-subunit (Ad-TSHR289). Both IL-17(+/+) and IL-17(-/-) mice developed anti-TSHR antibodies and hyperthyroidism at equally high frequencies on the BALB/c genetic background. In contrast, some IL-17(+/+), but none of IL-17(-/-), mice became hyperthyroid on the NOD-H2(h4) genetic background, indicating the crucial role of IL-17 for development of Graves' hyperthyroidism in non-susceptible NOD-H2(h4), but not in susceptible BALB/c mice. In the T-cell recall assay, splenocytes and lymphocytes from the draining lymph nodes from either mouse strains, irrespective of IL-17 gene status, produced IFN-γ and IL-10 but not other cytokines including IL-17 in response to TSHR antigen. Thus, the functional significance of Th17 may not necessarily be predictable from cytokine expression patterns in splenocytes or inflammatory lesions. In conclusion, this is, to our knowledge, the first report showing that the role of Th17 cells for the pathogenesis of a certain autoimmune disease depends on the mouse genetic backgrounds.

Higher susceptibility of NOG mice to xenotransplanted tumors.

The purpose of tumorigenicity testing, as applied not only to cell substrates used for viral vaccine manufacture but also stem cells used for cell-based therapy, is to discriminate between cells that have the capacity to form tumors and cells that do not. Therefore, tumorigenicity testing is essential in assessing the safety of these biological materials. Recently developed NOD/Shi-scid IL2Rg(null) (NOG) mice have been shown to be superior to NOD/Shi-scid (SCID) mice for xenotransplantation of both normal and cancerous cells. To select a suitable mouse strain as a xenogenic host for tumorigenicity testing, we compared the susceptibility of NOG (T, B, and NK cell-defective), SCID (T and B cell-defective), and the traditionally used nude (T cell-defective) mice to tumor formation from xenotransplanted HeLa S3 cells. When 10(4) HeLa S3 cells were subcutaneously inoculated into the flanks of these mice, the tumor incidence on day 22 was 10/10 (100%) in NOG, 2/10 (20%) in SCID, and 0/10 (0%) in nude mice. The subcutaneous tumors formed reproducibly and semiquantitatively in a dose-dependent manner. Unexpectedly, half of the NOG mice (5/10) that had been inoculated with a mere 10(1) HeLa S3 cells formed progressively growing subcutaneous tumors on day 78. We confirmed that the engrafted tumors originated from inoculated HeLa S3 cells by immunohistochemical staining with anti-HLA antibodies. These data suggest that NOG mice may be the best choice as a suitable strain for testing tumorigenicity.