Dietary fat quality influences the risk of type 2 diabetes and cardiovascular disease. A low-grade inflammation is suggested to contribute to the disease development, often accompanied by obesity. Whereas n-3 polyunsaturated fatty acids (PUFA) have been considered anti-inflammatory, n-6 PUFA have been proposed to act pro-inflammatory. Saturated fatty acids (SFA) act pro-inflammatory in vitro. This thesis aimed to investigate effects of different fatty acids on low-grade inflammation in observational and interventional studies. In Paper I and II, fatty acid composition in serum cholesterol esters was used as objective marker of dietary fat quality and related to serum C-reactive protein (CRP) and other circulating inflammatory markers in two population-based cohorts, conducted in middle-aged men and elderly men and women, respectively. In Paper III and IV, the impact of diets differing in fat quality on inflammation and oxidative stress was investigated in randomised controlled studies, in subjects with metabolic syndrome and abdominal obesity. In Paper I and II, a low proportion of linoleic acid (18:2 n-6) in serum was associated with higher CRP concentrations, indicating that a low intake of vegetable fats may be related to low-grade inflammation. High CRP concentrations were also associated with high proportions of palmitoleic (16:1) and oleic (18:1) acids and high stearoyl coenzymeA desaturase index, possibly reflecting altered fat metabolism and/or high SFA intake in this population. When comparing two high-fat diets rich in either saturated or monounsaturated fat, and two low-fat diets with or without long-chain n-3 PUFA supplementation during 12 weeks (Paper III), no differences in inflammation or oxidative stress markers were observed. Moreover, a 10-week intervention (Paper IV) with high linoleic acid intake showed no adverse effects on inflammation or oxidative stress. Instead, interleukin-1 receptor antagonist and tumor necrosis factor receptor-2 decreased after linoleic acid intake compared with a diet high in SFA. The results in this thesis indicate that dietary n-6 PUFA found in vegetable fats is associated with lower inflammation marker levels, and to some extent reduces systemic inflammation when compared with SFA. Supplementation of n-3 PUFA did not exert any systemic anti-inflammatory effects, maybe due to a relatively low dose.

Pancreatic cancer is characterized by its desmoplastic tumor microenvironment and the infiltration of immunosuppressive cells. It is a devastating disease where most patients are diagnosed at a late stage and the treatment options are few. The development of new treatments is surly needed. One treatment option explored is the use of immunotherapy with the intent to activate the immune system and change the balance from pro-tumor to anti-tumor. This thesis presents the idea of using oncolytic adenoviruses called LOAd-viruses that are armed with immunostimulatory- and microenvironment-modulating transgenes. For effective treatment of pancreatic cancer, the virus needs to be able to be given in addition to standard therapy, the chemotherapy gemcitabine. In paper I, the immunomodulatory effect of gemcitabine was evaluated in blood from pancreatic cancer patients receiving their first 28-day cycle of treatment with infusions day 1, 8 and 15 followed by a resting period. Gemcitabine reduced the level of immunosup-pressive cells and molecules but the effect did not last throughout the resting period. On the other hand, gemcitabine did not affect the level or proliferative function of effector T cells indicating that gemcitabine could be combined with immunotherapy. The LOAd700 virus expresses a novel membrane-bound trimerized form of CD40L (TMZ-CD40L). In paper II, LOAd700 showed to be oncolytic in pancreatic cancer cell lines as well as being immunostimulatory as shown by its capacity to activate dendritic cells (DCs), myeloid cells, endothelium, and to promote expansion of antigen-specific T cells. In paper III, LOAd703 armed with both 4-1BBL and TMZ-CD40L was evaluated. LOAd703 gave a more profound effect than LOAd700 on activation of DCs and the virus was also capable of reducing factors in stellate cells connected to the desmo-plastic and immunosuppressive microenvironment. In paper IV, LOAd713 armed with TMZ-CD40L in combination with a single-chain variable fragment against IL-6R was evaluated. The virus could kill pancreatic cancer cells lines through oncolysis and could also reduce factors involved in desmoplasia in stellate cells. Most interestingly, LOAd713 could reduce the up-regulation of PD-1/PD-L1 in DCs after CD40 activation. Taken together, LOAd703 and LOAd713 seem to have interesting features with their combination of immunostimulation and microenvironment modulation. At present, LOAd703 is evaluated in a clinical trial for pancreatic cancer (NCT02705196).

Viruses are entities which are made of a few genes and are reliant on obligate parasitism to propagate. Due to the obligate connection to their hosts, virus evolution is constrained to the type of host. Viruses however do transmit to evolutionary distinct hosts; in these cases, the phylogenetic relationship of the hosts usually are close. In some instances, RNA-viruses have made host jumps between evolutionary distant hosts, such as the host jump from invertebrates to vertebrates, and fungi to arthropod. Partitiviruses are double stranded RNA viruses which mainly infect fungi and plants. The defining characteristic of these double stranded RNA viruses are the double layered capsids which are formed by a single open reading frame (ORF). The capsid proteins form icosahedral virus particles which are in the magnitude of 30-40 nm. Metagenomic studies have discovered partitiviruses originating from an insect in the Odanata family, a finding which contradicts the fungal host specificity of partitiviruses. The finding of the Hubei.PLV 11 thus implies the existence of a partitiviruses containing structural elements in their capsids which could be involved in the infection of arthropods. Thus, this virus could be used as a model for a structural comparison with its fungi infecting relatives with hopes to identify common viral structural factors necessary for the infection of arthropods. For this purpose, the Hubei.PLV ORF was cloned and then transfected into insect Spodoptera frugiperda (Sf-9) cells using a baculovirus expression system, “bac-to-bac” expression system. The FLAG-tagged capsid proteins were expressed by the Sf-9 cells to be approximately 60 kDa. After ultra-centrifugation in a sucrose gradient, some spontaneous assembly into the expected ~40 nm icosahedral virus-like particles were observed using low resolution scanning electron microscopy. The observed particles were also confirmed by a dynamic light scattering experiment (DLS) and a higher resolution cryo-EM microscope. Thus, the bac-to-bac expression system can be used to produce VLPs from this genus of viruses, and this metagenomically derived virus genome. However, for future success in defining a high-resolution model of this virus, it is recommended that the Sf-9 culture volume is sufficiently high for enough particle production which is necessary for a high-resolution map. The other virus, the Southern pygmy squid Flavilike virus (SpSFV) has been suggested to be the oldest relative of the land based flaviviruses. The SpSFV was found to be the most divergent of the flaviviruses, and to infect invertebrates. Solving for the structure of the SpSFV and comparing it to vertebrate infecting flaviviruses could therefore lead to the identification of factors necessary for the adaptation to vertebrates and thus the humoral immunity by flaviviruses. The soluble E-protein was expressed using the bac-to-bac expression system. The protein was indicated to be multiglycosylated and approximately 50 kDa which is in line with other strains in the genus. Affinity chromatography did not elute this protein, likely due to the His-tag not being spatially available. Cation exchange could elute some protein, but not much from the small ~30 mL culture. To conclude, VLP assembly was confirmed by the Hubei.PLV, thus, solving for the structure is a distinct possibility when a larger Sf-9 culture is used to produce the VLPs. For the SpSFV soluble E-protein, the protein is secreted into the supernatant of the Sf-9 cultures, making purification a possibility. For this, a large Sf-9 culture can be used to produce this protein and then purify it with a cat-ion exchange chromatography.

PFOS (pluorooctane sulfonic acid) and PCB 180 (2,2′,3,4,4′,5,5′-heptachlorobiphenyl) are endocrine-disrupting chemicals (EDCs) ubiquitously found throughout the environment, given their persistence and extreme long biological half-life. PFOS and PCB 180 are predicted to disrupt retinoic acid receptor (Rar) signaling, interfering with important events of brain development, including neural differentiation and proliferation. Despite accumulating reports on the adversities of these EDCs, studies on the underlying mechanism continue to be largely unknown. The aim of this study was to validate transcriptional markers predictive of Rar disruption and to assess whether the same effects are induced by PFOS and PCB 180 exposure. Murine neural progenitor C17.2 cells were employed to mimic the developing brain. The cells were exposed to increasing nanomolar concentrations (nM) of Rar (ant)agonist, PFOS, and PCB 180. Interestingly, of all the transcriptional markers investigated, Ccn2 (cellular communication network factor 2), Il18 (Interleukin -18), and Ntn1(Netrin 1) were significantly altered by the Rar agonist (P< 0.05). Likewise, the expression of Il18 and Ntn1 was also altered by developmental exposure to PFOS and PCB 180. Altogether, these findings indicate that Il18 and Ntn1 may be promising markers for studying developmental neurotoxicity induced by disruption of the retinoic acid pathway.

Motile cilia play critical roles in the human body, including expelling mucus from the lungs and facilitating the transport of oocytes and sperm through the fallopian tubes. Understanding the complex structure and motility of cilia, as well as the diseases associated with them, is of big importance. This study investigates the proteins expressed in ciliated cells from both respiratory and reproductive tissues using multiplex immunofluorescence. We determined the subcellular localization of 134 proteins in the fallopian tube, endometrium, cervix, nasopharynx, and bronchus, focusing on five subcellular regions: the cilia tip, transition zone, basal body, cytoplasm, and nucleus. This analysis was conducted using an automated image analysis method developed specifically for this project. Our findings revealed a high correlation in protein expression across all tissues, although several proteins exhibited distinct expression patterns between different tissues. Notably, the fallopian tube showed a higher correlation with the nasopharynx and bronchus than with the endometrium and cervix. Within these proteins, six gene clusters were identified, with the two largest clusters being strongly associated with ciliary structure. This study enhances our understanding of motile ciliary structures and ciliated cells, identifying key proteins for further research into cilia motion, function, and related diseases.

Various molecular pathways in the brain shape our understanding of good and bad, as well as our motivation to seek and avoid such stimuli. This work evolves around how systemic inflammation causes aversion; and why general unpleasant states such as sickness, stress, pain and nausea are encoded by our brain as undesirable; and contrary to these questions, how drugs of abuse can subjugate the motivational neurocircuitry of the brain. A common feature of these various disease states is involvement of the motivational neurocircuitry - from mesolimbic to striatonigral pathways. Having an intact motivational system is what helps us evade negative outcomes and approach natural positive reinforcers, which is essential for our survival. During disease-states the motivational neurocircuitry may be overthrown by the molecular mechanisms that originally were meant to aid us. In study I, to investigate how inflammation is perceived as aversive, we used a behavioral test based on Pavlovian place conditioning with the aversive inflammatory stimulus E. coli lipopolysaccharide (LPS). Using a combination of cell-type specific gene deletions, pharmacology, and chemogenetics, we uncovered that systemic inflammation triggered aversion by MyD88-dependent activation of the brain endothelium followed by COX1-mediated cerebral prostaglandin E2 (PGE2) synthesis. Moreover, we showed that inflammation-induced PGE2 targeted EP1 receptors on striatal dopamine D1 receptor–expressing neurons and that this signaling sequence induced aversion through GABA-mediated inhibition of dopaminergic cells. Finally, inflammation-induced aversion was not an indirect consequence of fever or anorexia but constituted an independent inflammatory symptom triggered by a unique molecular mechanism. Collectively, these findings demonstrate that PGE2-mediated modulation of the dopaminergic circuitry is a key mechanism underlying inflammation-induced aversion. In study II, we investigate the role of peripheral IFN-γ in LPS induced conditioned place aversion by employing a strategy based on global and cell-type specific gene deletions, combined with measures of gene-expression. LPS induced IFN-ɣ expression in the blood, and deletion of IFN-ɣ or its receptor prevented conditioned place aversion (CPA) to LPS. LPS increased the expression of chemokine Cxcl10 in the striatum of normal mice. This induction was absent in mice lacking IFN-ɣ receptors or Myd88 in blood brain barrier endothelial cells. Furthermore, inflammation-induced aversion was blocked in mice lacking Cxcl10 or its receptor Cxcr3. Finally, mice with a selective deletion of the IFN-ɣ receptor in brain endothelial cells did not develop inflammation-induced aversion. Collectively, these findings demonstrate that circulating IFN-ɣ binding to receptors on brain endothelial cells which induces Cxcl10, is a central link in the signaling chain eliciting inflammation-induced aversion. In study III, we explored the role of melanocortin 4 receptors (MC4Rs) in aversive processing using genetically modified mice in CPA to various stimuli. In normal mice, robust aversions were induced by systemic inflammation, nausea, pain and kappa opioid receptor-induced dysphoria. In sharp contrast, mice lacking MC4Rs displayed preference towards most of the aversive stimuli, but were indifferent to pain. The unusual flip from aversion to reward in mice lacking MC4Rs was dopamine-dependent and associated with a change from decreased to increased activity of the dopamine system. The responses to aversive stimuli were normalized when MC4Rs were re-expressed on dopamine D1 receptor-expressing cells or in the striatum of mice otherwise lacking MC4Rs. Furthermore, activation of arcuate nucleus proopiomelanocortin neurons projecting to the ventral striatum increased the activity of striatal neurons in a MC4R-dependent manner and elicited aversion. Our findings demonstrate that melanocortin signaling through striatal MC4Rs is critical for assigning negative motivational valence to harmful stimuli. The neurotransmitter acetylcholine has been implied in reward learning and drug addiction. However, the role of cholinergic receptor subtypes in such processes remains elusive. In study IV we investigated the function of muscarinic M4Rs on dopamine D1R expressing neurons and acetylcholinergic neurons, using transgenic mice in various reward-enforced behaviors and in a “waiting”-impulsivity test. Mice lacking M4-receptors from D1-receptor expressing neurons exhibited an escalated reward seeking phenotype towards cocaine and natural reward, in Pavlovian conditioning and an operant self-administration task, respectively. In addition, the M4-D1RCre mice showed impaired waiting impulsivity in the 5-choice-serial-reaction-time-task. On the contrary, mice without M4Rs in acetylcholinergic neurons were unable to learn positive reinforcement to natural reward and cocaine, in an operant runway paradigm and in Pavlovian conditioning.  Immediate early gene expression mirrored the behavioral findings arising from M4R-D1R knockout, as cocaine induced cFos and FosB was significantly increased in the forebrain of M4-D1RCre mice, whereas it remained normal in the M4R-ChatCre mice. Our study illustrates that muscarinic M4Rs on specific neural populations, either cholinergic or D1R-expressing, are pivotal for learning processes related to both natural reward and drugs of abuse, with opposing functionality.