Patients with type II diabetes present alterations in glucose homeostasis due to insufficient amount of insulin (β-cell dysfunction) and inability to properly use the insulin that is secreted (insulin resistance). Combined genetical and environmental factors are believed to be responsible for these dysfunctions and the resulting impairment in glucose homeostasis. The pancreatic gland is composed of exocrine and endocrine tissues. The endocrine part of the organ couples glucose sensing to insulin release. Within this endocrine gland, also known as islets of Langerhans, the insulin secreting β-cell is the main player and therefore highly important for proper glucose metabolism. In this thesis, mice were developed in order to assess the role of BMP signaling molecule and Arsenite induced ATPase-1 (Asna1) for pancreas development and β-cell function. The mature β-cell responds to elevated glucose levels by secreting insulin in a tightly controlled manner. This physiological response of the β-cell to elevated blood glucose levels is critical for maintenance of normoglycaemia and impaired Glucose stimulated insulin secretion (GSIS) is a prominent feature of overt type 2 diabetes. Thus, the identification of signals and pathways that ensure and stimulate GSIS in β-cells is of great clinical interest. Here we show (Paper I) that BMPRIA and its high affinity ligand BMP4 are expressed in fetal and adult islets. We also provide evidence that BMPRIA signaling in adult β-cell is required for GSIS, and that both transgenic expression of Bmp4 in β-cells or systemic administration of BMP4 protein to mice enhances GSIS. Thus, BMP4-BMPRIA signaling in β-cells positively regulates the genetic machinery that ensures GSIS. Arsenite induced ATPase (Asna1), the homologue of the bacterial ArsA ATPase, is expressed in insulin producing cells of both mammals and the nematode Caenorhabditis elegans (C.elegans). Asna1 has been proposed to act as an evolutionary conserved regulator of insulin/insulin like factor signaling. In C.elegans, asna-1 has been shown to regulate growth in a non-cell autonomous and IGF-receptor dependent manner. Here we show that transgenic expression of ASNA1 in β-cells of mice leads to enhanced Aktactivity and β-cell hyperplasia (manuscript). ASNA1 transgenic mice develop, however, diabetes due to impaired insulin secretion. The expression of genes involved in secretion stimulus coupling and insulin exocytosis is perturbed in islets of these mice. These data suggest that activation of ASNA1, here mimicked by enhanced expression, positively influences β-cell mass but negatively affects insulin secretion.

Multiple myeloma, or myeloma, is a bone marrow cancer which characterizes by uncontrolled proliferation of mutant plasma cells. It is a disease that claims many lives every year, mostly due to the absence of curative treatment. Finding a suitable treatment is therefor of great importance. One way to study different diseases is to use a gene editing method for knockdown or knockout of specific genes. The main aim of this project was to design guide RNAs, to be able to use CRISPR/Cas9 for knockout of the two genes BMPR1A and BMPR2 in different myeloma cell lines (KJON, INA-6 and IH-1). This, to be able to study the expression and function of these genes. Further aim of the project was to investigate potential SMAD activation by treatment with different bone morphogenetic proteins (BMPs). However, due to limited time this could not be carried through. Six guide RNAs were designed and ligated into pLentiCRISPRv2. Plasmid amplification was done by transformation of Escherichia coli. To check the quality of the plasmids, PCR, gel electrophoresis and Sanger sequencing was performed. The results from the gel electrophoresis showed that nine of the twelve samples for BMPR1A and seven of the thirteen samples for BMPR2, that were tested, were positive. The results from the Sanger sequencing confirmed that all guides that were tested (BMPR1A 3.2.3, BMPR1A 4.2.2, BMPR2 1.1.4 and BMPR2 2.1.2), were properly ligated into the plasmids. The main aim of the project was successfully accomplished, but additional work is needed for any further conclusions.

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