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Background The CD274 (PD-L1)/PDCD1 (PD-1) immune checkpoint interaction may promote cancer progression, but the expression patterns and prognostic significance of PD-L1 and PD-1 in the colorectal cancer microenvironment are inadequately characterised. Methods We used a custom 9-plex immunohistochemistry assay to quantify the expression patterns of PD-L1 and PD-1 in macrophages, T cells, and tumour cells in 910 colorectal cancer patients. We evaluated cancer-specific mortality according to immune cell subset densities using multivariable Cox regression models. Results Compared to PD-L1– macrophages, PD-L1+ macrophages were more likely M1-polarised than M2-polarised and located closer to tumour cells. PD-L1+ macrophage density in the invasive margin associated with longer cancer-specific survival [Ptrend = 0.0004, HR for the highest vs. lowest quartile, 0.52; 95% CI: 0.34–0.78]. T cell densities associated with longer cancer-specific survival regardless of PD-1 expression (Ptrend + and PD-1– subsets). Higher densities of PD-1+ T cell/PD-L1+ macrophage clusters associated with longer cancer-specific survival (Ptrend Conclusions PD-L1+ macrophages show distinct polarisation profiles (more M1-like), spatial features (greater co-localisation with tumour cells and PD-1+ T cells), and associations with favourable clinical outcome. Our comprehensive multimarker assessment could enhance the understanding of immune checkpoints in the tumour microenvironment and promote the development of improved immunotherapies.

It is unknown what circumstances promote particular bacterial defenses against bacterial viruses (phages). Almeida & Hoikkala et al. show that mucin, derived from mucus, greatly accelerates CRISPR-Cas defenses against phage in an opportunistic pathogen. Parasitism by bacteriophages has led to the evolution of a variety of defense mechanisms in their host bacteria. However, it is unclear what factors lead to specific defenses being deployed upon phage infection. To explore this question, we co-evolved the bacterial fish pathogen Flavobacterium columnare and its virulent phage V156 in presence and absence of a eukaryotic host signal (mucin) for sixteen weeks. The presence of mucin leads to a dramatic increase in CRISPR spacer acquisition, especially in low nutrient conditions where over 60% of colonies obtain at least one new spacer. Additionally, we show that the presence of a competitor bacterium further increases CRISPR spacer acquisition in F. columnare. These results suggest that ecological factors are important in determining defense strategies against phages, and that the phage-bacterium interactions on mucosal surfaces may select for the diversification of bacterial immune systems.

Like many bacterial species, Borrelia burgdorferi, the pleomorphic bacterium that causes Lyme borreliosis, produces outer membrane vesicles (OMVs). Borrelial OMVs (BbOMVs) have been identified as containing virulence factors, such as outer surface proteins (Osps) A, B, and C, as well as DNA. However, the pathogenicity of BbOMVs in disease development is still unclear. In this study, we characterized purified BbOMVs by analyzing their size and immunolabeling for known antigenic markers: OspA, OspC, p39, and peptidoglycan. In addition, BbOMVs were cocultured with human non-immune cells for cytotoxicity analysis. The results demonstrated that, on average, the vesicles were small, ranging between 11 and 108 nm in diameter. In addition, both OspA and OspC, as well as Lyme arthritis markers p39 and peptidoglycan, were detected from BbOMVs. Furthermore, BbOMVs were cocultured with non-immune cells, which did not result in cell death. Combined, these results suggested that BbOMVs could participate in the induction of infection by functioning as a decoy for the host immune system. Furthermore, BbOMVs might serve as a means for persistent antigens to remain in the host for prolonged periods of time. peerReviewed

Programmed cell death ligand (PD-L1)/PD-1 expression has been studied in a variety of cancers and blockage of PD-L1/PD-1 pathway is a cornerstone of immunotherapy. We studied PD-L1/PD-1 immunohistochemical expression in 47 thyroid gland specimens in groups of (1) Hashimoto thyroiditis (HT) only; (2) HT and follicular epithelial dysplasia (FED); and (3) HT, FED, and papillary thyroid carcinoma (PTC). PD-1 positivity was found in immune cells, namely in lymphocytes, macrophages, and plasma cells with mean values for lymphocytes and macrophages 9% in HT group, 4% in FED group, and 4% in PTC group. PD-L1 positivity was identified in both immune cells and in the normal epithelial cells. In the HT group, mean PD-L1 staining on immune cells was 6%, in FED group 5%, and in PTC group 7%. The mean PD-L1 staining on the epithelial cells in the inflammatory parenchyma was 11.7% in HT, 13.4% in FED, and 8.3% in PTC group. The mean PD-L1 staining of FED foci was 47.2% in FED group and 33.6% in PTC group. The mean tumor proportion score (TPS) was 10.4%, and the mean combined positive score (CPS) was 15.5. At the moment, PTC is not a target of immunotherapy. However, understanding the complex issue of concurrent inflammation and autoimmunity can importantly influence the cancer treatment in future. publishedVersion

Little is known how acute exercise-induced inflammation and metabolic stress affect immune cell bioenergetics and the portion of its components. Therefore, we investigated acute effects of eccentric-only (E), concentric-only (C) and combined eccentric-concentric resistance exercise (E + C) bouts on cellular respiration of peripheral blood mononuclear cells (PBMCs). Twelve strength-trained young men performed bench press resistance exercises in randomized order. Venous blood samples were drawn at pre-, 5 min post- and 24 h post-exercise. Several PBMC respiration states were measured using high-resolution respirometry. Levels of leukocytes, interleukin 6 (IL-6), C-reactive protein (CRP), creatine kinase (CK), blood lactate and maximum voluntary isometric force were measured from the same time points. Effects of blood lactate and pH change on bioenergetics of PBMCs were investigated ex vivo. PBMC routine respiration (p = 0.017), free routine capacity (p = 0.025) and ET-capacity (p = 0.038) decreased immediately after E + C. E responded in opposite manner 5 min post-exercise compared to E + C (p = 0.013) and C (p = 0.032) in routine respiration, and to E + C in free routine activity (p = 0.013). E + C > C > E was observed for increased lactate levels and decreased isometric force that correlated with routine respiration (R = −0.369, p = 0.035; R = 0.352, p = 0.048). Lactate and pH change did not affect bioenergetics of PBMCs. Acute resistance exercise affected cellular respiration of PBMCs, with training volume and the amount of metabolic stress appear influential. Results suggest that acute inflammation response does not contribute to changes seen in cellular respiration, but the level of peripheral muscle fatigue and metabolic stress could be explaining factors. peerReviewed

Antibiotics have long been used in the raising of animals for agricultural, industrial or laboratory use. The use of subtherapeutic doses in diets of terrestrial and aquatic animals to promote growth is common and highly debated. Despite their vast application in animal husbandry, knowledge about the mechanisms behind growth promotion is minimal, particularly at the molecular level. Evidence from evolutionary research shows that immunocompetence is resource-limited, and hence expected to trade off with other resource-demanding processes, such as growth. Here, we ask if accelerated growth caused by antibiotics can be explained by genome-wide trade-offs between growth and costly immunocompetence. We explored this idea by injecting broad-spectrum antibiotics into wood tiger moth (Arctia plantaginis) larvae during development. We follow several life-history traits and analyse gene expression (RNA-seq) and bacterial (r16S) profiles. Moths treated with antibiotics show a substantial depletion of bacterial taxa, faster growth rate, a significant downregulation of genes involved in immunity and significant upregulation of growth-related genes. These results suggest that the presence of antibiotics may aid in up-keeping the immune system. Hence, by reducing the resource load of this costly process, bodily resources may be reallocated to other key processes such as growth.

Lyme borreliosis is a multisystemic disease caused by the pleomorphic bacteria of the Borrelia burgdorferi sensu lato complex. The exact mechanisms for the infection to progress into a prolonged sequelae of the disease are currently unknown, although immune evasion and persistence of the bacteria in the host are thought to be major contributors. The current study investigated B. burgdorferi infection processes in two human cell lines, both non-immune and non-phagocytic, to further understand the mechanisms of infection of this bacterium. By utilizing light, confocal, helium ion, and transmission electron microscopy, borrelial infection of chondrosarcoma (SW1353) and dermal fibroblast (BJ) cells were examined from an early 30-min time point to a late 9-days post-infection. Host cell invasion, viability of both the host and B. burgdorferi, as well as, co-localization with lysosomes and the presence of different borrelial pleomorphic forms were analyzed. The results demonstrated differences of infection between the cell lines starting from early entry as B. burgdorferi invaded BJ cells in coiled forms with less pronounced host cell extensions, whereas in SW1353 cells, micropodial interactions with spirochetes were always seen. Moreover, infection of BJ cells increased in a dose dependent manner throughout the examined 9 days, while the percentage of infection, although dose dependent, decreased in SW1353 cells after reaching a peak at 48 h. Furthermore, blebs, round body and damaged B. burgdorferi forms, were mostly observed from the infected SW1353 cells, while spirochetes dominated in BJ cells. Both infected host cell lines grew and remained viable after 9 day post-infection. Although damaged forms were noticed in both cell lines, co-localization with lysosomes was low in both cell lines, especially in BJ cells. The invasion of non-phagocytic cells and the lack of cytopathic effects onto the host cells by B. burgdorferi indicated one mechanism of immune evasion for the bacteria. The differences in attachment, pleomorphic form expressions, and the lack of lysosomal involvement between the infected host cells likely explain the ability of a bacterium to adapt to different environments, as well as, a strategy for persistence inside a host. peerReviewed

Immune suppressing molecule CD73 is overexpressed in various cancers and associated with poor survival. Little is so far known about the predictive value of CD73 in pancreatic ductal adenocarcinoma (PDAC). The purpose of this study was to investigate the prognostic significance of CD73 in PDAC. The study material consisted of 110 radically treated patients for PDAC. Tissue microarray blocks were constructed and stained immunohistochemically using CD73 antibody. Staining intensity and numbers of stained tumour cells, inflammatory cells, stroma, and blood vessels were assessed. High-level CD73 expression in tumour cells was positively associated with PD-L1 expression, perineural invasion, and histopathological grade. CD73 positivity in tumour-infiltrating lymphocytes was significantly associated with lymph node metastasis. Lymphocytic CD73 positivity was also associated with staining positivity in both stroma and vascular structures. In addition, CD73 positivity in vascular structures and stroma were associated with each other. There were no significant associations between CD73 positive tumour cells and CD73 positivity in any other cell types. PD-L1 expression was associated with CD73 staining positivity in stroma (p = 0.007) and also with histopathological grade (p = 0.033) and T class (p = 0.016) of the primary tumour. CD73 positivity in tumour cells was significantly associated with poor disease-specific (p = 0.021) and overall survival (p = 0.016). In multivariate analysis, CD73 positivity in tumour cells was an independent negative prognostic factor together with histopathological grade, TNM stage, and low immune cell score. In conclusion, high CD73 expression in tumour cells is associated with poor survival in PDAC independently of the number of tumour-infiltrating lymphocytes or TNM stage.

CRISPR-Cas systems are immune systems that protect bacteria and archaea against their viruses, bacteriophages. Immunity is achieved through the acquisition of short DNA fragments from the viral invader’s genome., CRISPR-Cas immune systems adapt to new threats by acquiring new spacers from invading nucleic acids such as phage genomes. However, some CRISPR-Cas loci lack genes necessary for spacer acquisition despite variation in spacer content between microbial strains. It has been suggested that such loci may use acquisition machinery from cooccurring CRISPR-Cas systems within the same strain. Here, following infection by a virulent phage with a double-stranded DNA (dsDNA) genome, we observed spacer acquisition in the native host Flavobacterium columnare that carries an acquisition-deficient CRISPR-Cas subtype VI-B system and a complete subtype II-C system. We show that the VI-B locus acquires spacers from both the bacterial and phage genomes, while the newly acquired II-C spacers mainly target the viral genome. Both loci preferably target the terminal end of the phage genome, with priming-like patterns around a preexisting II-C protospacer. Through gene deletion, we show that the RNA-cleaving VI-B system acquires spacers in trans using acquisition machinery from the DNA-cleaving II-C system. Our observations support the concept of cross talk between CRISPR-Cas systems and raise further questions regarding the plasticity of adaptation modules.

Wildlife inhabiting environments contaminated by radionuclides face putative detrimental effects of exposure to ionizing radiation, with biomarkers such as an increase in DNA damage and/or oxidative stress commonly associated with radiation exposure. To examine the effects of exposure to radiation on gene expression in wildlife, we conducted a de novo RNA sequencing study of liver and spleen tissues from a rodent, the bank vole Myodes glareolus. Bank voles were collected from the Chernobyl Exclusion Zone (CEZ), where animals were exposed to elevated levels of radionuclides, and from uncontaminated areas near Kyiv, Ukraine. Counter to expectations, we did not observe a strong DNA damage response in animals exposed to radionuclides, although some signs of oxidative stress were identified. Rather, exposure to environmental radionuclides was associated with upregulation of genes involved in lipid metabolism and fatty acid oxidation in the livers – an apparent shift in energy metabolism. Moreover, using stable isotope analysis, we identified that fur from bank voles inhabiting the CEZ had enriched isotope values of nitrogen: such an increase is consistent with increased fatty acid metabolism, but also could arise from a difference in diet or habitat between the CEZ and elsewhere. In livers and spleens, voles inhabiting the CEZ were characterized by immunosuppression, such as impaired antigen processing, and activation of leukocytes involved in inflammatory responses. In conclusion, exposure to low dose environmental radiation impacts pathways associated with immunity and lipid metabolism, potentially as a stress‐induced coping mechanism. peerReviewed

Short term variation in environmental conditions requires individuals to adapt via changes in behavior and/or physiology. In particular variation in temperature and humidity are common, and the physiological adaptation to changes in temperature and humidity often involves alterations in gene expression, in particular that of heat-shock proteins. However, not only traits involved in the resistance to environmental stresses, but also other traits, such as immune defenses, may be influenced indirectly by changes in temperature and humidity. Here we investigated the response of the ant F. exsecta to two temperature regimes (20 degrees C & 25 degrees C), and two humidity regimes (50% & 75%), for two populations. We measured the survival and the expression of six metabolism- and immunity-related genes, and furthermore compared the expression levels in each condition with the pre-experiment expression levels. Both populations survived equally well at the two humidities, but one population showed higher mortality at 25 degrees C than 20 degrees, at 50% humidity. Similarly, the two populations showed striking differences in their gene expression before the experiment, and in their responses to the environmental conditions. Surprisingly, instead of converging to similar expression levels in the same environmental conditions, gene expression diverged further apart. This indicates different reaction norms to both temperature and humidity for the two populations. Furthermore, our results suggest that also immune defenses are indirectly affected by environmental conditions.

Proproteiinikonvertaasi-entsyymit immuunijärjestelmän säätelyssä Immuunijärjestelmämme puolustaa elimistöä ulkoisia taudinaiheuttajia ja syöpäsoluja vastaan, mutta jos sen toiminnan säätely häiriintyy, elimistö saattaa altistua tulehduksellisille sairauksille. Tällaiset immuunijärjestelmän häiriötilat kuten nivelreuma, tyypin 1 diabetes ja astma kohdistuvat kasvavaan potilasjoukkoon kuormittaen yhteiskuntaa, minkä takia immuunisolujen toimintaa on välttämätöntä tutkia yksityiskohtaisemmin uusien hoitokeinojen kehittämiseksi. Yksi immuunijärjestelmämme säätelijöistä on proproteiinikonvertaasi (PCSK) -entsyymiperhe. Useat proteiinit tuotetaan soluissa aluksi toimimattomina proproteiineina, jotka sitten pilkotaan toimintakykyiseen muotoon molekyylisaksien, esimerkiksi PCSK-entsyymien avulla. Näillä entsyymeillä on tärkeä tehtävä solujen toiminnassa, mutta niiden merkitys immuunivälitteisissä tautitiloissa tunnetaan vielä puutteellisesti. Tässä väitöstutkimuksessa tarkasteltiin PCSK-entsyymejä immuunijärjestelmän säätelijöinä. Väitöstutkimuksen ensimmäisessä osatyössä havaittiin, että PCSK-entsyymi FURIN on välttämätön auttaja-T-solujen oikeanlaiselle erilaistumiselle ja immuunivasteelle solunsisäistä taudinaiheuttajaa vastaan. Tutkimuksessa löydettiin myös uusia FURIN-vuorovaikutuksia. Toisessa osatyössä näytettiin, että päinvastoin kuin nisäkkäillä, seeprakaloilla PCSK7-entsyymi on välttämätön alkionkehitykselle. Lisäksi PCSK7-entsyymin osoitettiin säätelevän immuunivasteen geenien ilmentymistä ja TGFβ-sytokiinin pilkkoutumista toimintakykyiseen muotoon. Kolmannessa osatyössä vertailtiin PCSK-geenien ilmentymistasoja potilailla, jotka sairastavat valtimonkovettumatautia eli ateroskleroosia. Tulokset osoittivat, että FURIN ja sen kohdesytokiinit BAFF ja APRIL ovat yliedustettuja verisuonen seinämään muodostuvan kolesterolikertymän eli ateroskleroottisen plakin immuunisoluissa. Tutkimuksessa selvisi myös, että FURIN-ilmentyminen lisääntyy immunologisen aktivaation seurauksena T-solujen lisäksi makrofageissa, mikä viittaa mahdolliseen FURIN-välitteiseen säätelyyn myös synnynnäisen immuunivasteen solutyypeissä. Väitöstutkimuksen tulokset antavat hyvän pohjan jatkaa yksityiskohtaisempien, erilaisille solutyypeille ominaisten säätelytapojen tutkimusta, mikä saattaa mahdollistaa uusien hoitomuotojen kehittämisen tulevaisuudessa. PCSK-entsyymien toimintaan vaikuttavat lääkemolekyylit ovat jo osoittautuneet hyödyllisiksi esimerkiksi syövän, infektiotautien ja ateroskleroosin kokeellisessa hoidossa. Our immune system is challenged daily by harmful pathogens and misbehaving cells of our own tissues. A powerful immune response is essential for overcoming these challenges. However, an uncontrolled reaction might expose the host to immune system disorders, including autoimmunity and allergies. Diseases such as rheumatoid arthritis, type 1 diabetes, and asthma are an increasingly heavy burden both for patients and society, and novel therapeutic and diagnostic interventions for preventing and treating immune system diseases are thus required. The regulation of the immune system is mediated by various cell types, secreted molecules and direct cell-to-cell contacts. Importantly, many biomolecules are initially synthesized as inactive proproteins, which then undergo a proteolytic maturation step. Proprotein convertase subtilisin/kexin (PCSK) enzymes catalyze the endoproteolytic activation of a variety of proproteins, including receptors, cytokines, and pathogenic agents. Although PCSKs have a critical role in cellular homeostasis, their immunoregulatory functions are still incompletely understood. This study investigated the role of PCSKs in immune regulation by using various methods and model organisms. The first-characterized and most studied PCSK member FURIN was shown to be critical for the correct polarization of T helper cells as well as for the cell-mediated immune response against a prototypic intracellular pathogen, Toxoplasma gondii in a mouse model. Further, T cell specific FURIN interacting proteins were captured from human T cells resulting in the identification of the RAC/DOCK2 interaction complex, which links FURIN to the regulation of cytoskeleton dynamics in T cells. In addition, the role of the evolutionarily most ancient PCSK enzyme, PCSK7, was studied during vertebrate development and in the regulation of gene expression using a zebra fish model. Interestingly, contrary to its mammalian counterpart, the zebra fish PCSK7 was found to be essential for embryogenesis and for the expression of genes coding proteins of immune system. This study also demonstrated that both the human and zebra fish PCSK7s are capable of proteolytically processing pro-TGFβ1, which might indicate a sophisticated spatiotemporal regulation of the cytokine’s bioavailability. Furthermore, a systematic approach was used to analyze the expression of PCSKs in human atherosclerotic vascular samples. FURIN was found to be the major upregulated PCSK in the immune cells of atherosclerotic plaques, where its substrate cytokines BAFF and APRIL were also overexpressed. In addition, this study demonstrated, for the first time, that the expression of FURIN is induced also in macrophages in response to immunoactivation. This suggests that FURIN plays a regulatory role also in innate immunity. Collectively, this study shows that PCSKs mediate both unique and redundant, and in most cases critical roles, in regulating the immune system. The utilization of two vertebrate model organisms and human patient samples demonstrated that PCSK mediated immunoregulatory functions are evolutionary conserved, but a deeper understanding of their cell-type specific spatiotemporal regulation is essential. This study provides new insights for the therapeutic targeting of PCSKs and their substrates suggesting novel ways to treat or diagnose immunological diseases.

Hyönteisiin lukeutuu monia merkittäviä tuholaisia, taudinvälittäjiä ja hyödyllisiä lajeja, minkä takia hyönteisten taudit, taudinaiheuttajat ja immuunipuolustus ovat ekologisesta, ekonomisesta ja lääketieteellisestä näkökulmasta tärkeitä tutkimuskohteita. Viimeaikaiset tutkimukset paljastavat hyönteisten ja muiden selkärangattomien immuunijärjestelmien pystyvän erikoistumaan ja luomaan pitkäkestoista immuniteettia. Jälkimmäinen ilmiö tunnetaan tieteellisissä artikkeleissa nimellä ”immunological priming”, jonka voisi kääntää suomeksi esimerkiksi ”immuunipohjustukseksi”. Immuunipohjustus on muistinkaltaista vastustuskykyä, joka auttaa elimistöä puolustautumaan tehokkaammin toistuvia tartuntoja vastaan. Taudinaiheuttajan laukaisemat immuunitoiminnot voivat altistuksen jälkeen pysyä jonkin aikaa aktiivisina, ja pienentää näin myöhemmän tartunnan riskiä. Mikäli tartuntariski on tällöin pienempi samanlaista kuin erilaista taudinaiheuttajaa kohtaan, on immuunipohjustus erikoistunutta. Erikoistuneisuuden havainnollistamiseksi on osoitettava, että immuunipohjustuksen on aktivoinut sen kohteena oleva taudinaiheuttaja. Tässä tutkimuksessa selvitettiin erikoistuneen immuunipohjustuksen mahdollista ilmenemistä täpläsiilikkään (Parasemia plantaginis) toukkien kahdessa peräkkäisessä altistuksessa samalle tai erilaisille Gram-negatiivisille bakteereille. Koebakteereina käytettiin kahta Serratia marcescens -kantaa, joista Db11-kanta on tunnettu hyönteisten taudinaiheuttaja, ja ATCC#13880 ympäristöstä eristetty kanta. Kontrollibakteerina käytettiin taudinaiheuttamiskyvytöntä Escherichia coli K12 -kantaa. Toukat altistettiin bakteereille ensin oraalisesti ravinnon välityksellä, ja viisi päivää myöhemmin injektiolla. Oraalisessa altistuksessa Db11-kannan havaittiin olevan kahta muuta bakteeria huomattavasti virulentimpi. Vaikka Db11 osoittautui tutkimuksen tarkoituksen kannalta liian virulentiksi, immuunipohjustusta havaittiin toukilla, jotka oli oraalisesti altistettu ja injektoitu ATCC#13880-kannalla, kun niiden selviytymistä verrattiin toukkiin, jotka oli altistettu E. coli:lla. Koska E. coli -altistus ei suojannut toukkia ATCC#13880-injektiota vastaan, voitiin immuunipohjustuksen päätellä olevan ATCC#13880-kannalle erikoistunutta. Tutkimuksemme osoitti selkärangattomien immuunijärjestelmän kyvyn erottaa erilaisia Gram-negatiivisia bakteereja toisistaan immuunipohjustuksen yhteydessä. Insects have various important roles as pests, disease vectors and beneficial species, which make insect diseases, pathogens and immune responses important study areas not only from ecological but also from economical and medical point of view. Recent studies have revealed remarkable specificity and long-lasting immunity in insect and other invertebrate immune systems. A phenomenon called ‘immunological priming’ produces memory-like immune response, which help the host to fight against recurrent infections. Immune functions induced by a pathogen can remain enhanced for a period of time after the immune challenge, reducing the risk of re-infection. If the reduced risk relates more clearly to a similar than a different kind of pathogen, the immune response is considered to be specific. In order to demonstrate specificity in immunological priming, it is necessary to show that the priming was induced by the targeted pathogen. The aim of this study was to find out whether or not the wood tiger moth (Parasemia plantaginis) larvae show specific immunological priming after two consecutive immune challenges with the same or different Gram-negative bacteria. The experimental bacteria were two Serratia marcescens strains, a common insect pathogen Db11 and an environmental isolate ATCC#13880. The control bacterium was a non-pathogenic Escherichia coli K12 strain. The larvae were challenged in oral exposure and by injection. Db11 appeared to be considerably more virulent in oral exposure than the other two bacteria. Although Db11 proved to be too virulent for the main purpose of the study, immunological priming was observed in a group of larvae that had been orally exposed and five days later injected with ATCC#13880 in comparison to a group of larvae with prior E. coli exposure. Since the prior E. coli exposure did not provide protection against ATCC#13880 injection, the priming could be regarded as specific to ATCC#13880. This study demonstrated the ability of the invertebrate immune system to discriminate between different Gram-negative bacteria in the context of immunological priming.

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and AMP-activated protein kinase (AMPK) are major factors regulating energy homeostasis. In this study, we aimed to investigate how energy flux affects several hepatic functions mediated by these factors. We define a novel role of PGC-1α and AMPK as modulators of the immune system in the liver. We show that PGC-1α is involved in the regulation of a cluster of genes related to the immune system, most importantly Interleukin 1 receptor antagonist (IL1Rn). Since PGC-1α is responsive to energetic stress associated with fasting or physical exercise, the same stimuli promote IL1Rn in hepatocytes. We identify AMPK as an independent inducer of IL1Rn and hypothesise that it could account for the anti-inflammatory effect of the antidiabetic drug metformin. We also demonstrate that metformin reduces expression of Sirtuin 3 (SIRT3) in hepatocytes and promotes acetylation of mitochondrial protein. We suggest that this mechanism, in spite of increased mitochondrial biogenesis, contributes to reduced ATP synthesis in metformin-treated samples. In addition, we demonstrate that Pregnane X receptor (PXR) is induced in the liver during fasting and by PGC-1α in hepatocytes. Furthermore, we describe a negative regulatory mechanism involving SIRT1, activated by pyruvate and interfering with PXR signaling. We show that SIRT1 attenuates PGC-1α-mediated co-activation of PXR and its target genes, i.e. Cyp3a11, with possible implications for drug and xenobiotic metabolism. In conclusion, we demonstrate how energetic stress affects various hepatic functions mediated by PGC-1α and AMPK. Moreover, we describe SIRT1 and metformin as factors capable of modulating this response. Tiivistelmä Peroksisomiproliferaattori-aktivoituvan reseptori gamman koaktivaattori 1α (PGC-1α) ja AMP:n aktivoima proteiinikinaasi (AMPK) ovat keskeisiä energiametabolian säätelijöitä. Tässä tutkimuksessa oli tavoitteena selvittää kuinka energiataso vaikuttaa useisiin, näiden tekijöiden säätelemiin maksan toimintoihin. Osoitamme että PGC-1α ja AMPK tekijöillä on ennestään tuntematon merkitys immuunijärjestelmän säätelyssä maksassa. Näytämme myös, että PGC-1α säätelee joukkoa geenejä, joiden tehtävä liittyy immuunijärjestelmään, tärkeimpänä Interleukiini 1 reseptori antagonistia (IL1Rn). Paastoon ja fyysiseen aktiivisuuteen liittyvä energiastressi aktivoi PGC-1α:aa ja näiden samojen stimuluksien havaittiin lisäävän myös IL1Rn tasoa hepatosyyteissä. Havaitsimme AMPK:n olevan itsenäinen IL1Rn indusori ja hypoteesimme mukaan tämä voi välittää diabeteslääkkeenä käytettävän metformiinin anti-inflammatorisia vaikutuksia. Osoitamme myös, että metformiini alentaa Sirtuiini (SIRT) 3:n ekspressiota maksasoluissa ja lisää mitokondriaalisten proteiinien asetylaatiota. Uskomme tämän mekanismin, huolimatta lisääntyneestä mitokondrioiden biogeneesistä, myötävaikuttavan vähentyneeseen ATP synteesiin metformiinikäsitellyissä näytteissä. Lisäksi osoitamme, että paasto ja PGC-1α indusoivat Pregnaani X reseptorin (PXR) ilmentymistä maksasoluissa. Kuvaamme myös PXR signalointiin vaikuttavan ja pyruvaatin aktivoiman, SIRT1:n välitteisen, negatiivisen säätelymekanismin. SIRT1 estää PGC-1α välitteistä PXR koaktivaatiota ja kohdegeenien, kuten Cyp3a11, aktivaatiota, millä voidaan olettaa olevan merkitystä lääkeaineiden ja vierasaineiden metaboliaan. Yhteenvetona osoitamme, että energiastressi PGC-1α:n ja AMPK:n välittämänä vaikuttaa useisiin maksan toimintoihin. Lisäksi näytämme, että SIRT1 ja metformiini voivat moduloida näitä vaikutuksia.

Stenholm, Johanna. Immune system adaptations during competition period in female cross-country skiers. Master’s Thesis in Exercise Physiology, Department of Biology of Physical Activity. University of Jyväskylä. 95pp. Purpose. This study was undertaken to characterize the extent of immune and endocrine changes in competition period and related to two competition weekends in well trained athletes in different parts of the competition period. An additional purpose was to evaluate if the changes in immunological variables would have an effect on the incidence of upper-respiratory-tract infections. The effect of the nutrition, nutrient and training status was also studied. Methods. Ten (10) national level female skiers were investigated as they followed their normal race preparation routines. Blood samples were taken for basal and recovery measurements in the mornings approximately an hour after the athletes had woken up. Saliva samples were taken in the basal measurement morning, in the first normal distance competition morning, immediately after finishing the race and in the recovery measurement morning. The ski race distances were between 4-12 kilometres and the race finishing time were between 12 and 45 minutes. The first competition was in early December and the second took place in Finnish championships in late January. The second competition of the present athletes took place in extremely cold weather (approximately -20 Celsius degrees). If the athletes were not able to participate to the scheduled competition, they were measured during the next possible weekend. The athletes filled their daily training diaries, food diaries both 3 days before the competition and during the competition weekend, and they reported upper-respiratory tract (URTI)-symptoms using WURSS-21 questionnaire. Results. URTI-symptoms were the most common reason for the athletes to miss training. There was a significant difference (p

Runsas altistuminen auringolle on tunnetusti haitallista ihmisten ja eläinten hyvinvoinnille. Eveliina Markkula tutki väitöskirjatyössään, miten ultravioletti B (UVB) -säteilylle altistuminen vaikuttaa kalojen vastustuskykyyn ja tautialttiuteen.- Ilmakehän otsonikerroksen oheneminen viime vuosikymmenten aikana on johtanut UVB-säteilyn lisääntymiseen maan pinnalla. UVB-säteily tunkeutuu myös kirkkaisiin järvi- ja merivesiin ja voi näin aiheuttaa haittaa kaloille, Markkula kertoo.UVB-säteilyn on jo aiemmin todettu lisäävän kalojen varhaisten elinvaiheiden epämuodostumia ja kuolleisuutta. Kertaluonteinenkin altistuminen lampuilla tuotetulle UVB-säteilylle aiheuttaa muutoksia kalan immuunijärjestelmässä. Sama tapahtuu myös ihmisillä ja jyrsijöillä.Pitkä, neljästä kuuteen viikkoon kestävä altistuminen keinotekoiselle UVB- säteilylle aiheuttaa kalojen immuunitoiminnoissa muutoksia, jotka eroavat lyhyissä altistuksissa havaituista. Nämä haittavaikutukset eivät kuitenkaan kasaannu, ja kalat kykenevät ainakin osittain sopeutumaan kohonneisiin säteilyarvoihin.Erilaisista elinympäristöistä peräisin olevien lajien sopeutumista tutkittaessa havaittiin, että karppi oli kirkkaissa vesissä esiintyvää kirjolohta herkempi valkosolujen toimintakyvyn muutoksille. Molemmilla lajeilla altistuminen UVB-säteilylle heikensi kalojen kuntoa.Markkulan tutkimuksessa immunologisten muutosten merkitystä kalan vastustuskykyyn tutkittiin kahden viikon mittaisella altistamisella UVB-säteilylle. Tutkimuksessa havaittiin, että UVB-säteily lisää kirjolohen herkkyyttä lois- ja bakteeri-infektiolle. Säteilyn ja kalojen tautialttiuden välillä on siis yhteys.- Skandinavian leveysasteilla säteilytasot eivät vaaranna ulkona kasvatettuja lohenpoikasia. Luonnollinen auringon säteily tai vähän kohonnut UVB-taso ei 20 viikkoa kestävässä kokeessa aiheuttanut haittaa kaloille, Markkula huomauttaa.Merkittävästi lisääntynyttä UVB-säteilyä voidaan kuitenkin pitää uhkana kalojen terveydelle, sillä lohenpoikasten kasvu ja kunto heikkenivät sekä immunologiset häiriöt lisääntyivät, kun kaloja altistettiin säteilylle, joka vastaa 20 prosentin otsonikatoa.Markkulan väitöstutkimuksen tuloksia voidaan hyödyntää kalanviljelyssä ja immunologian tutkimuksessa. Tutkimus tuo myös uutta tietoa siitä, miten ympäristön muutosten vaikutuksia voidaan arvioida. Solar ultraviolet B (UVB) radiation is an environmental stressor known to have harmful impacts on aquatic organisms. While the immunomodulatory effects of UVB on fish have been demonstrated in short-term exposures, the present work focused on the long-term effects of low-dose UVB on fish species adapted to live at high or low levels of natural solar radiation. In general, the immunomodulatory effects of the long-term exposures with low UVB doses were less profound than those induced by short-term exposures.Suppressed functioning of head kidney phagocytes was detected after different exposure regimes ranging from a single UVB dose to an irradiation of 6 weeks, and was the most sensitive of the studied cellular parameters. Natural cytotoxic cells and lymphocytes were more inconsistently affected by radiation treatments, as were the hematological and humoral parameters of the blood. Cortisol-mediated stress reaction was common after short-term exposures. A comparison of the fish species revealed that benthic carp (Cyprinus carpio) is more sensitive to UVB than rainbow trout (Oncorhynchus mykiss), a representative species of clear water habitats. In outdoor experiments, the exposure simulating 20 % stratospheric ozone loss for 8 weeks negatively affected the growth, condition, and plasma IgM concentration of the juvenile Atlantic salmon (Salmo salar) indicating potentially compromised immune defense.The exposure simulating 8 % ozone loss for 20 weeks, however, caused no detectable change in fish when compared to the natural solar radiation. The relationship between the UVB exposure and disease resistance was demonstrated in rainbow trout irradiated over 1-2 weeks. Resistance of exposed fish to parasite Diplostomum spathaeum was significantly decreased, and clearance of bacteria Yersinia ruckeri from the tissues of infected fish was affected as well. The results suggest that increased UVB radiation levels can potentially harm fish health in long-term exposures, and that there is an association between UVB exposure and disease resistance.

Anssi Vainikka on väitöskirjassaan selvittänyt vaikuttavatko särjen ja suutarin ornamenttien tuottoon kytketyt hormonit niiden immuunipuolustuskykyyn. Vastoin ennakko-oletuksia, testosteronin tai estradiolin ei havaittu alentavan immuunipuolustuskykyä. Myöskään ornamenttien ja immuunipuolustuskyvyn mittareiden väliltä ei löytynyt seksuaalivalinnan teorioiden ennustamia positiivisia yhteyksiä. Korkea testosteronipitoisuus oli kuitenkin yhteydessä koirassuutarin hyvään kuntoon ja ornamentit kertovatkin koiraan hyvästä elinkyvystä. Testosterone is known to enhance reproductive success, but has also been proposed to suppress immune defence. Prior to spawning, male roach (Rutilus rutilus L.) produce testosterone-associated breeding tubercles those have been found to signal parasite load and parasite resistance. Tench (Tinca tinca (L.)) is sexually dimorphic throughout the year, and in addition to their large pelvic fins males produce ventral protuberances of unknown function during breeding. The indicator value of male tench ornaments, immunosuppressivity of testosterone, cortisol and oestradiol in roach and tench, and the level of stress during spawning in roach were studied. A study of crucian carp (Carassius carassius (L.)) aimed to link individual’s behavioural decisions to somatic growth, reproductive effort and future survival. In these studies, cortisol but neither testosterone nor oestradiol was found to have immunosuppressive effects. Neither did an immunological challenge decrease the concentration of testosterone. Although testosterone was positively related to the condition factor in tench, it was only weakly associated to the expression of male ornaments. High spawning-time prevalence of epidermal papillomatosis in male roach was suggested to result from sex-differences in spawning stress. Body depth gain in crucian carp was associated to growth in a manner dependent on predator presence, but the behavioural decisions of an individual did not correlate with measures of growth or reproductive effort. I suggest that stress steroids contribute to the honesty of sexual signalling in the studied cyprinids, whereas testosterone in both sexes may act as a condition-dependent hormone having a positive effect on sexual signalling and primary sexual traits, but being metabolically costly at high levels.