PANcreatic-DERived factor (PANDER, FAM3B) has been shown to regulate glycemic levels via interactions with both pancreatic islets and the liver. Although PANDER is predominantly expressed from the endocrine pancreas, recent work has provided sufficient evidence that the liver may also be an additional tissue source of PANDER production. At physiological levels, PANDER is capable of disrupting insulin signaling and promoting increased hepatic glucose production. As shown in some animal models, strong expression of PANDER, induced by viral delivery within the liver, induces hepatic steatosis. However, no studies to date have explicitly characterized the transcriptional regulation of PANDER from the liver. Therefore, our investigation elucidated the nutrient and hormonal regulation of the hepatic PANDER promoter. Initial RNA-ligated rapid amplification of cDNA ends identified a novel transcription start site (TSS) approximately 26 bp upstream of the PANDER translational start codon not previously revealed in pancreatic β-cell lines. Western evaluation of various murine tissues demonstrated robust expression in the liver and brain. Promoter analysis identified strong tissue-specific activity of the PANDER promoter in both human and murine liver-derived cell lines. The minimal element responsible for maximal promoter activity within hepatic cell lines was located between -293 and -3 of the identified TSS. PANDER promoter activity was inhibited by both insulin and palmitate, whereas glucose strongly increased expression. The minimal element was responsible for maximal glucose-responsive and basal activity. Co-transfection reporter assays, chromatin-immunoprecipitation (ChIP) and site-directed mutagenesis revealed that the carbohydrate-responsive element binding protein (ChREBP) increased PANDER promoter activity and interacted with the PANDER promoter. E-box 3 was shown to be critical for basal and glucose responsive expression. In summary, in-vitro and in-vivo glucose is a potent stimulator of the PANDER promoter within the liver and this response may be facilitated by ChREBP.

This article contains raw and processed data related to research published in "Quantitative Proteomic Profiling Reveals Hepatic Lipogenesis and Liver X Receptor Activation in the PANDER Transgenic Model" (M.G. Athanason, W.A. Ratliff, D. Chaput, C.B. MarElia, M.N. Kuehl, S.M., Jr. Stevens, B.R. Burkhardt (2016)) [1], and was generated by "spike-in" SILAC-based proteomic analysis of livers obtained from the PANcreatic-Derived factor (PANDER) transgenic mouse (PANTG) under various metabolic conditions [1]. The mass spectrometry output of the PANTG and wild-type B6SJLF mice liver tissue and resulting proteome search from MaxQuant 1.2.2.5 employing the Andromeda search algorithm against the UniprotKB reference database for Mus musculus has been deposited to the ProteomeXchange Consortium (http://www.proteomexchange.org) via the PRIDE partner repository with dataset identifiers PRIDE: PXD004171 and doi:10.6019/PXD004171. Protein ratio values representing PANTG/wild-type obtained by MaxQuant analysis were input into the Perseus processing suite to determine statistical significance using the Significance A outlier test (p<0.05). Differentially expressed proteins using this approach were input into Ingenuity Pathway Analysis to determined altered pathways and upstream regulators that were altered in PANTG mice.

Pancreatic-derived factor (PANDER; also known as FAM3B) is a uniquely structured protein strongly expressed within and secreted from the endocrine pancreas. PANDER has been hypothesized to regulate fasting and fed glucose homeostasis, hepatic lipogenesis and insulin signaling, and to serve a potential role in the onset or progression of type 2 diabetes (T2D). Despite having potentially pivotal pleiotropic roles in glycemic regulation and T2D, there has been limited generation of stable animal models for the investigation of PANDER function, and there are no models on well-established genetic murine backgrounds for T2D. Our aim was to generate an enhanced murine model to further elucidate the biological function of PANDER. Therefore, a pure-bred PANDER knockout C57BL/6 (PANKO-C57) model was created and phenotypically characterized with respect to glycemic regulation and hepatic insulin signaling. The PANKO-C57 model exhibited an enhanced metabolic phenotype, particularly with regard to enhanced glucose tolerance. Male PANKO-C57 mice displayed decreased fasting plasma insulin and C-peptide levels, whereas leptin levels were increased as compared with matched C57BL/6J wild-type mice. Despite similar peripheral insulin sensitivity between both groups, hepatic insulin signaling was significantly increased during fasting conditions, as demonstrated by increased phosphorylation of hepatic PKB/Akt and AMPK, along with mature SREBP-1 expression. Insulin stimulation of PANKO-C57 mice resulted in increased hepatic triglyceride and glycogen content as compared with wild-type C57BL/6 mice. In summary, the PANKO-C57 mouse represents a suitable model for the investigation of PANDER in multiple metabolic states and provides an additional tool to elucidate the biological function and potential role in T2D.