Browsing by Subject "ACTIVATION"

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  • Guenther, Carla; Faisal, Imrul; Uotila, Liisa; Llort Asens, Marc; Harjunpää, Heidi; Savinko, Terhi; Öhman, Tiina; Yao, Sean; Moser, Markus; Morris, Stephan W.; Tojkander, Sari; Fagerholm, Susanna (2019)
    beta2-integrins are essential for immune system function because they mediate immune cell adhesion and signaling. Consequently, a loss of beta2-integrin expression or function causes the immunodeficiency disorders, Leukocyte Adhesion Deficiency (LAD) type I and III. LAD-III is caused by mutations in an important integrin regulator, kindlin-3, but exactly how kindlin-3 regulates leukocyte adhesion has remained incompletely understood. Here we demonstrate that mutation of the kindlin-3 binding site in the b2-integrin (TTT/AAA-b2-integrin knock-in mouse/KI) abolishes activation of the actin-regulated myocardin related transcription factor A/serum response factor (MRTF-A/SRF) signaling pathway in dendritic cells and MRTF-A/SRF-dependent gene expression. We show that Ras homolog gene family, member A (RhoA) activation and filamentous-actin (F-actin) polymerization is abolished in murine TTT/AAA-b2-integrin KI dendritic cells, which leads to a failure ofMRTF-A to localize to the cell nucleus to coactivate genes together with SRF. In addition, we show that dendritic cell gene expression, adhesion and integrin-mediated traction forces on ligand coated surfaces is dependent on the MRTF-A/SRF signaling pathway. The participation of b2-integrin and kindlin-3-mediated cell adhesion in the regulation of the ubiquitous MRTF-A/SRF signaling pathway in immune cells may help explain the role of b2-integrin and kindlin-3 in integrin-mediated gene regulation and immune system function.
  • Zhou, Kecheng; Dichlberger, Andrea; Martinez-Seara, Hector; Nyholm, Thomas K. M.; Li, Shiqian; Kim, Young Ah; Vattulainen, Ilpo; Ikonen, Elina; Blom, Tomas (2018)
    Membrane proteins are functionally regulated by the composition of the surrounding lipid bilayer. The late endosomal compartment is a central site for the generation of ceramide, a bioactive sphingolipid, which regulates responses to cell stress. The molecular interactions between ceramide and late endosomal transmembrane proteins are unknown. Here, we uncover in atomistic detail the ceramide interaction of Lysosome Associated Protein Transmembrane 4B (LAPTM4B), implicated in ceramide-dependent cell death and autophagy, and its functional relevance in lysosomal nutrient signaling. The ceramide-mediated regulation of LAPTM4B depends on a sphingolipid interaction motif and an adjacent aspartate residue in the protein's third transmembrane (TM3) helix. The interaction motif provides the preferred contact points for ceramide while the neighboring membrane-embedded acidic residue confers flexibility that is subject to ceramide-induced conformational changes, reducing TM3 bending. This facilitates the interaction between LAPTM4B and the amino acid transporter heavy chain 4F2hc, thereby controlling mTORC signaling. These findings provide mechanistic insights into how transmembrane proteins sense and respond to ceramide.
  • Sajanti, Antti; Lyne, Sean B.; Girard, Romuald; Frantzen, Janek; Rantamaki, Tomi; Heino, Iiro; Cao, Ying; Diniz, Cassiano; Umemori, Juzoh; Li, Yan; Takala, Riikka; Posti, Jussi P.; Roine, Susanna; Koskimäki, Fredrika; Rahi, Melissa; Rinne, Jaakko; Castren, Eero; Koskimäki, Janne (2020)
    P75 neurotrophic receptor (p75NTR) is an important receptor for the role of neurotrophins in modulating brain plasticity and apoptosis. The current understanding of the role of p75NTR in cellular adaptation following pathological insults remains blurred, which makes p75NTR's related signaling networks an interesting and challenging initial point of investigation. We identified p75NTR and related genes through extensive data mining of a PubMed literature search including published works related to p75NTR from the past 20 years. Bioinformatic network and pathway analyses of identified genes (n=235) were performed using ReactomeFIViz in Cytoscape based on the highly reliable Reactome functional interaction network algorithm. This approach merges interactions extracted from human curated pathways with predicted interactions from machine learning. Genome-wide pathway analysis showed total of 16 enriched hierarchical clusters. A total of 278 enriched single pathways were also identified (p
  • Suleymanova, Ilida; Balassa, Tamas; Tripathi, Sushil; Molnar, Csaba; Saarma, Mart; Sidorova, Yulia; Horvath, Peter (2018)
    Astrocytes are involved in various brain pathologies including trauma, stroke, neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, or chronic pain. Determining cell density in a complex tissue environment in microscopy images and elucidating the temporal characteristics of morphological and biochemical changes is essential to understand the role of astrocytes in physiological and pathological conditions. Nowadays, manual stereological cell counting or semi-automatic segmentation techniques are widely used for the quantitative analysis of microscopy images. Detecting astrocytes automatically is a highly challenging computational task, for which we currently lack efficient image analysis tools. We have developed a fast and fully automated software that assesses the number of astrocytes using Deep Convolutional Neural Networks (DCNN). The method highly outperforms state-of-the-art image analysis and machine learning methods and provides precision comparable to those of human experts. Additionally, the runtime of cell detection is significantly less than that of other three computational methods analysed, and it is faster than human observers by orders of magnitude. We applied our DCNN-based method to examine the number of astrocytes in different brain regions of rats with opioid-induced hyperalgesia/tolerance (OIH/OIT), as morphine tolerance is believed to activate glia. We have demonstrated a strong positive correlation between manual and DCNN-based quantification of astrocytes in rat brain.
  • Babkovskaia, Natalia; Rannik, Ullar; Phillips, Vaughan; Siebert, Holger; Wehner, Birgit; Boy, Michael (2016)
    The purpose of this study is to investigate the interaction between small-scale turbulence and aerosol and cloud microphysical properties using direct numerical simulations (DNS). We consider the domain located at the height of about 2000aEuro-m from the sea level, experiencing transient high supersaturation due to atmospheric fluctuations of temperature and humidity. To study the effect of total number of particles (N-tot) on air temperature, activation and supersaturation, we vary N-tot. To investigate the effect of aerosol dynamics on small-scale turbulence and vertical air motion, we vary the intensity of turbulent fluctuations and the buoyant force. We find that even a small number of aerosol particles (55.5aEuro-cm(-3)), and therefore a small droplet number concentration, strongly affects the air temperature due to release of latent heat. The system comes to an equilibrium faster and the relative number of activated particles appears to be smaller for larger N-tot. We conclude that aerosol particles strongly affect the air motion. In a case of updraught coursed by buoyant force, the presence of aerosol particles results in acceleration of air motion in vertical direction and increase of turbulent fluctuations.
  • Chan, Keefe T.; Blake, Shaun; Zhu, Haoran; Kang, Jian; Trigos, Anna S.; Madhamshettiwar, Piyush B.; Diesch, Jeannine; Paavolainen, Lassi; Horvath, Peter; Hannan, Ross D.; George, Amee J.; Sanij, Elaine; Hannan, Katherine M.; Simpson, Kaylene J.; Pearson, Richard B. (2020)
    Exquisite regulation of PI3K/AKT/mTORC1 signaling is essential for homeostatic control of cell growth, proliferation, and survival. Aberrant activation of this signaling network is an early driver of many sporadic human cancers. Paradoxically, sustained hyperactivation of the PI3K/AKT/mTORC1 pathway in nontransformed cells results in cellular senescence, which is a tumor-suppressive mechanism that must be overcome to promote malignant transformation. While oncogene-induced senescence (OIS) driven by excessive RAS/ERK signaling has been well studied, little is known about the mechanisms underpinning the AKT-induced senescence (AIS) response. Here, we utilize a combination of transcriptome and metabolic profiling to identify key signatures required to maintain AIS. We also employ a whole protein-coding genome RNAi screen for AIS escape, validating a subset of novel mediators and demonstrating their preferential specificity for AIS as compared with OIS. As proof of concept of the potential to exploit the AIS network, we show that neurofibromin 1 (NF1) is upregulated during AIS and its ability to suppress RAS/ERK signaling facilitates AIS maintenance. Furthermore, depletion of NF1 enhances transformation of p53-mutant epithelial cells expressing activated AKT, while its overexpression blocks transformation by inducing a senescent-like phenotype. Together, our findings reveal novel mechanistic insights into the control of AIS and identify putative senescence regulators that can potentially be targeted, with implications for new therapeutic options to treat PI3K/AKT/mTORC1-driven cancers.
  • Kortesoja, Maarit; Trofin, Raluca Elena; Hanski, Leena (2020)
    The obligate intracellular bacterium, Chlamydia pneumoniae, has been identified as a risk factor for several chronic inflammatory diseases in addition to respiratory tract infections. The dissemination of C. pneumoniae from respiratory tract to secondary sites of infection occurs via infected monocyte / macrophage line cells, in which C. pneumoniae can persist as an antibiotic-refractory phenotype. To allow more detailed studies on the epithelium-monocyte/macrophage transition of the infection, new in vitro bioassays are needed. To this end, a coculture system with human continuous cell lines was established. Respiratory epithelial HL cells were infected with C. pneumoniae and THP-1 monocytes were added into the cultures at 67 h post infection. After a 5 h coculture, THP-1 cells were collected with a biotinylated HLA antibody and streptavidin-coated magnetic beads and C. pneumoniae genome copy numbers in THP-1 determined by quantitative PCR. The assay was optimized for cell densities, incubation time, THP-1 separation technique and buffer composition, and its robustness was demonstrated by a Z' value of 0.6. The mitogen-activated protein kinase (MAPK) inhibitors: SP600125 (JNK inhibitor), SB203580 (p38 inhibitor) and FR180204 (ERK inhibitor) suppressed the transfer of C. pneumoniae from HL to THP-1 cells, making them suitable positive controls for the assay. Based on analysis of separate steps of the process, the MAPK inhibitors suppress the bacterial entry to THP-1 cells. The transfer of C. pneumoniae from epithelium to phagocytes represents a crucial step in the establishment of persistent infections by this pathogen, and the presented methods enables future studies to block this process by therapeutic means.
  • Räisänen, Ismo T.; Heikkinen, Anna Maria; Pakbaznejad Esmaeili, Elmira; Tervahartiala, Taina; Pajukanta, Riitta; Silbereisen, Angelika; Bostanci, Nagihan; Sorsa, Timo (2019)
    Background This cross-sectional study aims to investigate if a point-of-care (PoC) test of active matrix metalloproteinase-8 (aMMP-8) predicts levels of inflammation amplifier triggering receptor expressed on myeloid cells-1 (TREM-1) and its putative ligand the neutrophil peptidoglycan recognition protein 1 (PGLYRP1) in saliva. Methods Forty-seven adolescents, aged 15 to 17 years, were tested with aMMP-8 PoC test, which was followed by a full-mouth clinical examination of the assessment of periodontal, mucosal, and oral health. TREM-1 and PGLYRP1 levels were analyzed by ELISA. The immunofluorometric assay (IFMA) specific for aMMP-8 was used as the reference method. Results Fourteen saliva samples out of a total of 47 showed positivity for aMMP-8 PoC test. Both the TREM-1 and the aMMP-8 (IFMA) levels were significantly elevated among the aMMP-8 PoC test positives compared with the PoC test negatives (P <0.05). Moreover, aMMP-8 levels assessed by IFMA showed a strong positive correlation with TREM-1 levels in saliva (r = 0.777, P <0.001). The number of sites with a probing depth of >= 4 mm was significantly lower among the adolescents that had a negative aMMP-8 PoC test result, and TREM-1 levels <75 pg/mL (P <0.05). In contrast, adolescents with a positive aMMP-8 PoC test result (i.e., elevated aMMP-8 levels) together with elevated TREM-1 levels had a significantly higher number of periodontal pockets with >= 4 mm (P <0.001). Conclusion The present study validated usability of aMMP-8 PoC test for predicting "proinflammatory" salivary profile and periodontal health status in adolescents.
  • Rekker, Kadri; Altmae, Signe; Suhorutshenko, Marina; Peters, Maire; Martinez-Blanch, Juan F.; Codoner, Francisco M.; Vilella, Felipe; Simon, Carlos; Salumets, Andres; Velthut-Meikas, Agne (2018)
    The endometrium undergoes extensive changes to prepare for embryo implantation and microRNAs (miRNAs) have been described as playing a significant role in the regulation of endometrial receptivity. However, there is no consensus about the miRNAs involved in mid-secretory endometrial functions. We analysed the complete endometrial miRNome from early secretory (pre-receptive) and mid-secretory (receptive) phases from fertile women and from patients with recurrent implantation failure (RIF) to reveal differentially expressed (DE) miRNAs in the mid-secretory endometrium. Furthermore, we investigated whether the overall changes during early to mid-secretory phase transition and with RIF condition could be reflected in blood miRNA profiles. In total, 116 endometrial and 114 matched blood samples collected from two different population cohorts were subjected to small RNA sequencing. Among fertile women, 91 DE miRNAs were identified in the mid-secretory vs. early secretory endometrium, while no differences were found in the corresponding blood samples. The comparison of mid-secretory phase samples between fertile and infertile women revealed 21 DE miRNAs from the endometrium and one from blood samples. Among discovered novel miRNAs, chr2_4401 was validated and showed up-regulation in the mid-secretory endometrium. Besides novel findings, we confirmed the involvement of miR-30 and miR-200 family members in mid-secretory endometrial functions.
  • Räisänen, Ismo T.; Sorsa, Timo; van der Schoor, Gerrit-Jan; Tervahartiala, Taina; van der Schoor, Peter; Gieselmann, Dirk-Rolf; Heikkinen, Anna Maria (2019)
    This cross-sectional study compares the effectiveness of an active MMP-8 (aMMP-8) point-of-care (PoC)/chairside mouthrinse test to the conventional bleeding on probing (BOP) (cutoff 20%) test in detecting subclinical periodontitis/pre-periodontitis in Finnish adolescents. The study was carried out at the Kotka Health Center, Finland. A total of 47 adolescents (30 boys/17 girls) aged 15-17 were first tested with the aMMP-8 PoC test, followed by a full-mouth evaluation of clinical parameters of oral health including periodontal, oral mucosal, and caries assessment. A periodontist performed these clinical examinations. The aMMP-8 PoC test result had much stronger association with subclinical periodontitis than the BOP 20% test (2.8-5.3 times stronger in terms of odds ratio). The aMMP-8 PoC test had >= 2 times higher sensitivity than the BOP 20% test with, generally, the same specificity. Further, the aMMP-8 PoC test had generally better accuracy and lower false negative percentages. The aMMP-8 PoC test seemed to be more effective than the conventional BOP test in detecting subclinical periodontitis/pre-periodontitis in adolescents reducing the risk of their undertreatment. However, the sample size may be a limiting factor, and more studies are needed to confirm our results for both adolescents and adults.
  • Sorsa, Timo; Alassiri, Saeed; Grigoriadis, Andreas; Räisänen, Ismo T.; Pärnänen, Pirjo; Nwhator, Solomon O.; Gieselmann, Dirk-Rolf; Sakellari, Dimitra (2020)
    The aim of this study was to investigate the utility of incorporating active matrix metalloproteinase-8 (aMMP-8) as a biomarker into the new periodontitis classification system (stage/grade) presented in 2018. This study included 150 Greek adults aged 25-78, of whom 74 were men and 76 women. Participants were tested with an aMMP-8 point-of-care mouthrinse test, after which a full-mouth clinical examination was performed to assess their periodontal and oral health. The aMMP-8 levels in mouthrinse were significantly lower among healthy patients compared with patients in more severe periodontitis stages and grades (Kruskal-Wallis test and Dunn-Bonferroni test for pairwise post-hoc comparisons; p <0.01 and p <0.05, respectively). Furthermore, aMMP-8 levels were less correlated with plaque levels than bleeding on probing (BOP) (Spearman's rho = 0.269, p <0.001; Spearman's rho = 0.586, p <0.001); respectively). Thus, aMMP-8 was more robust to the confounding effects of oral hygiene than traditional periodontal parameter bleeding on probing. The aMMP-8 point-of-care mouthrinse test can be utilized as an adjunctive and preventive diagnostic tool to identify periodontal disease, classified by stage and grade, and ongoing periodontal breakdown chairside in clinical practice in only 5 min. Overall, integrating aMMP-8 into the new periodontitis classification system seems beneficial.
  • Hentila, Jaakko; Nissinen, Tuuli A.; Korkmaz, Ayhan; Lensu, Sanna; Silvennoinen, Mika; Pasternack, Arja; Ritvos, Olli; Atalay, Mustafa; Hulmi, Juha J. (2019)
    Muscle wasting in cancer cachexia can be alleviated by blocking activin receptor type 2 (ACVR2) ligands through changes in protein synthesis/degradation. These changes in cellular and protein metabolism may alter protein homeostasis. First, we elucidated the acute (1-2 days) and 2-week effects of blocking ACVR2 ligands by soluble activin receptor 2B (sACVR2B-Fc) on unfolded protein response (UPR), heat shock proteins (HSPs) and redox balance in a healthy mouse skeletal muscle. Second, we examined UPR, autophagy and redox balance with or without sACVR2B-Fc administration in muscle and liver of C26 tumor-bearing mice. The indicators of UPR and HSPs were not altered 1-2 days after a single sACVR2B-Fc administration in healthy muscles, but protein carbonyls increased (p <0.05). Two weeks of sACVR2B-Fc administration increased muscle size, which was accompanied by increased UPR markers: GRP78 <0.05), phosphorylated elF2 alpha <0.01) and HSP47 (p <0.01). Additionally, protein carbonyls and reduced form of glutathione increased (GSH) (p <0.05). On the other hand, C26 cancer cachexia manifested decreased UPR markers (p-elF2 alpha, HSP47, p-JNK; p <0.05) and antioxidant GSH (p <0.001) in muscle, whereas the ratio of oxidized to reduced glutathione increased (GSSG/GSH; p <0.001). Administration of sACVR2B-Fc prevented the decline in GSH and increased some of the UPR indicators in tumor-bearing mice. Additionally, autophagy markers LC3II/I (p <0.05), Beclin-1 (p <0.01), and P62 (p <0.05) increased in the skeletal muscle of tumor-bearing mice. Finally, indicators of UPR, PERK, p-elF2 alpha and GRP78, increased (p <0.05), whereas ATF4 was strongly decreased (p <0.01) in the liver of tumor-bearing mice while sACVR2B-Fc had no effect. Muscle GSH and many of the altered UPR indicators correlated with tumor mass, fat mass and body mass loss. In conclusion, experimental cancer cachexia is accompanied by distinct and tissue-specific changes in proteostasis. Muscle hypertrophy induced by blocking ACVR2B ligands may be accompanied by the induction of UPR and increased protein carbonyls but blocking ACVR2B ligands may upregulate antioxidant protection.
  • Riederer, Monika; Ojala, Pauli J.; Hrzenjak, Andelko; Tritscher, Michaela; Hermansson, Martin; Watzer, Bernhard; Schweer, Horst; Desoye, Gernot; Heinemann, Akos; Frank, Sasa (2010)
  • Pajunoja, Aki; Lambe, Andrew T.; Hakala, Jani; Rastak, Narges; Cummings, Molly J.; Brogan, James F.; Hao, Liqing; Paramonov, Mikhail; Hong, Juan; Prisle, Nonne L.; Malila, Jussi; Romakkaniemi, Sami; Lehtinen, Kari E. J.; Laaksonen, Ari; Kulmala, Markku; Massoli, Paola; Onasch, Timothy B.; Donahue, Neil M.; Riipinen, Ilona; Davidovits, Paul; Worsnop, Douglas R.; Petaja, Tuukka; Virtanen, Annele (2015)
    Aerosol climate effects are intimately tied to interactions with water. Here we combine hygroscopicity measurements with direct observations about the phase of secondary organic aerosol (SOA) particles to show that water uptake by slightly oxygenated SOA is an adsorption-dominated process under subsaturated conditions, where low solubility inhibits water uptake until the humidity is high enough for dissolution to occur. This reconciles reported discrepancies in previous hygroscopicity closure studies. We demonstrate that the difference in SOA hygroscopic behavior in subsaturated and supersaturated conditions can lead to an effect up to about 30% in the direct aerosol forcinghighlighting the need to implement correct descriptions of these processes in atmospheric models. Obtaining closure across the water saturation point is therefore a critical issue for accurate climate modeling.
  • Colecchia, D; Stasi, M; Leonardi, M; Manganelli, F; Nolano, M; Veneziani, BM; Santoro, L; Eskelinen, Eeva-Liisa; Chiariello, M; Bucci, Cecilia (2018)
    Charcot-Marie-Tooth type 2B (CMT2B) disease is a dominant axonal peripheral neuropathy caused by 5 mutations in the RAB7A gene, a ubiquitously expressed GTPase controlling late endocytic trafficking. In neurons, RAB7A also controls neuronal-specific processes such as NTF (neurotrophin) trafficking and signaling, neurite outgrowth and neuronal migration. Given the involvement of macroautophagy/autophagy in several neurodegenerative diseases and considering that RAB7A is fundamental for autophagosome maturation, we investigated whether CMT2B-causing mutants affect the ability of this gene to regulate autophagy. In HeLa cells, we observed a reduced localization of all CMT2B-causing RAB7A mutants on autophagic compartments. Furthermore, compared to expression of RAB7AWT, expression of these mutants caused a reduced autophagic flux, similar to what happens in cells expressing the dominant negative RAB7AT22N mutant. Consistently, both basal and starvation-induced autophagy were strongly inhibited in skin fibroblasts from a CMT2B patient carrying the RAB7AV162M mutation, suggesting that alteration of the autophagic flux could be responsible for neurodegeneration.
  • Liu, Jiao; Puolanne, Eero; Schwartzkopf, Matthias; Arner, Anders (2020)
    The "Woody" or "Wooden" breast disease is a severe myopathy of pectoralis major muscle recently identified within rapidly growing broiler lines all around the world with a prevalence rate around 20%, or even higher. Although of significant ethical and economic impact, little is known regarding the structural and functional aspects of the contractile apparatus in the woody breast muscle. The aim of the present study was to determine physiological properties of the contractile system in the morphologically intact muscle fibers of focally damaged woody breast in comparison with normal muscle fibers to gain insight into the muscle function of the animal and possibly mechanisms involved in the disease development. Muscle samples were taken from woody breast (non-lesioned areas) and normal breast muscles from broilers. Length-tension curves, maximal active stress, maximal shortening velocity, calcium sensitivity, rate of tension development, lattice spacing and muscle biochemical composition were investigated on single skinned fibers. Sarcomeres of woody breast fibers were more compliant, which is very likely related to the wider spacing (18% wider compared to controls) between thick and thin filament. No differences were found in optimal sarcomere length (2.68 +/- 0.04 vs. 2.65 +/- 0.05 mu m) nor in maximal active stress (116 +/- 17 vs. 125 +/- 19 mN mm(-2)). However, woody breast fibers had less steep descending arm as shown in length-tension curve. Woody breast muscle fibers had 40% bigger sarcomeric volume compared to controls. Content of contractile proteins (myosin and actin), and maximal shortening velocity were unchanged indicating that the growth in woody breast muscle fiber was associated with synthesis of new contractile units with unaltered kinetics. Calcium sensitivity was decreased in woody breast muscle fibers significantly. In conclusion, the results show that the rapid growth of muscle in woody breast disease is associated with significant structural and functional changes in the pectoralis major musculature, associated with alterations in the mechanical anchoring of contractile filaments.
  • Gospodaryov, Dmytro; Strilbytska, Olha M.; Semaniuk, Uliana; Perkhulyn, Natalia; Rovenko, Bohdana M.; Yurkevych, Ihor S.; Barata, Ana G.; Dick, Tobias P.; Lushchak, Oleh; Jacobs, Howard T. (2020)
    Mitochondrial alternative NADH dehydrogenase (aNDH) was found to extend lifespan when expressed in the fruit fly. We have found that fruit flies expressing aNDH from Ciona intestinalis (NDX) had 17-71% lifespan prolongation on media with different protein-tocarbohydrate ratios except NDX-expressing males that had 19% shorter lifespan than controls on a high protein diet. NDX-expressing flies were more resistant to organic xenobiotics, 2,4-dichlorophenoxyacetic acid and alloxan, and inorganic toxicant potassium iodate, and partially to sodium molybdate treatments. On the other hand, NDX-expressing flies were more sensitive to catechol and sodium chromate. Enzymatic analysis showed that NDX-expressing males had higher glucose 6-phosphate dehydrogenase activity, whilst both sexes showed increased glutathione S-transferase activity.
  • Rajendran, Jayasimman; Purhonen, Janne; Tegelberg, Saara; Smolander, Olli-Pekka; Mörgelin, Matthias; Rozman, Jan; Gailus-Durner, Valerie; Fuchs, Helmut; de Angelis, Martin Hrabe; Auvinen, Petri; Mervaala, Eero; Jacobs, Howard T.; Szibor, Marten; Fellman, Vineta; Kallijärvi, Jukka (2019)
    Alternative oxidase (AOX) is a non-mammalian enzyme that can bypass blockade of the complex III-IV segment of the respiratory chain (RC). We crossed a Ciona intestinalis AOX transgene into RC complex III (cIII)-deficient Bcs1l(p.S78G) knock-in mice, displaying multiple visceral manifestations and premature death. The homozygotes expressing AOX were viable, and their median survival was extended from 210 to 590 days due to permanent prevention of lethal cardiomyopathy. AOX also prevented renal tubular atrophy and cerebral astrogliosis, but not liver disease, growth restriction, or lipodystrophy, suggesting distinct tissue-specific pathogenetic mechanisms. Assessment of reactive oxygen species (ROS) production and damage suggested that ROS were not instrumental in the rescue. Cardiac mitochondrial ultrastructure, mitochondrial respiration, and pathological transcriptome and metabolome alterations were essentially normalized by AOX, showing that the restored electron flow upstream of cIII was sufficient to prevent cardiac energetic crisis and detrimental decompensation. These findings demonstrate the value of AOX, both as a mechanistic tool and a potential therapeutic strategy, for cIII deficiencies.
  • Liu, Xingzhi; Zhang, Hongbo; Cheng, Ruoyu; Gu, Yanzheng; Yin, Yin; Sun, Zhiyong; Pan, Guoqing; Deng, Zhongbin; Yang, Huilin; Deng, Lianfu; Cui, Wenguo; Almeida Santos, Helder; Shi, Qin (2018)
    Antibody-based cancer immune therapy has attracted lots of research interest in recent years; however, it is greatly limited by the easy distribution and burst release of antibodies. In addition, after the clearance of the tissue, healthy tissue regeneration is another challenge for cancer treatment. Herein, we have developed a specific immunological tissue engineering scaffold using the agonistic mouse anti-human CD40 antibody (CD40mAb) incorporated into poly(l-lactide) (PLLA) electrospun fibers through the dopamine (PDA) motif (PLLA-PDA-CD40mAb). CD40mAb is successfully incorporated onto the surface of the electrospun fibrous scaffold, which is proved by immunofluorescence staining, and the PLLA-PDA-CD40mAb scaffold has an anti-tumor effect by locally releasing CD40mAb. Therefore, this immunological electrospun scaffold has very good potential to be developed as a powerful tool for localized tumor treatment, and this is the first to be reported in this area.
  • Lokki, A. Inkeri; Kaartokallio, Tea; Holmberg, Ville; Onkamo, Paivi; Koskinen, Lotta L. E.; Saavalainen, Paivi; Heinonen, Seppo; Kajantie, Eero; Kere, Juha; Kivinen, Katja; Pouta, Anneli; Villa, Pia M.; Hiltunen, Leena; Laivuori, Hannele; Meri, Seppo (2017)
    Preeclampsia (PE) is a common vascular disease of pregnancy with genetic predisposition. Dysregulation of the complement system has been implicated, but molecular mechanisms are incompletely understood. In this study, we determined the potential linkage of severe PE to the most central complement gene, C3. Three cohorts of Finnish patients and controls were recruited for a genetic case-control study. Participants were genotyped using Sequenom genotyping and Sanger sequencing. Initially, we studied 259 Finnish patients with severe PE and 426 controls from the Southern Finland PE and the Finnish population-based PE cohorts. We used a custom-made single nucleotide polymorphism (SNP) genotyping assay consisting of 98 SNPs in 18 genes that encode components of the complement system. Following the primary screening, C3 was selected as the candidate gene and consequently Sanger sequenced. Fourteen SNPs from C3 were also genotyped by a Sequenom panel in 960 patients with severe PE and 705 controls, including already sequenced individuals. Three of the 43 SNPs observed within C3 were associated with severe PE: rs2287845 (p = 0.038, OR = 1.158), rs366510 (p = 0.039, OR = 1.158), and rs2287848 (p = 0.041, OR = 1.155). We also discovered 16 SNP haplotypes with extreme linkage disequilibrium in the middle of the gene with a protective (p = 0.044, OR = 0.628) or a predisposing (p = 0.011, OR = 2.110) effect to severe PE depending on the allele combination. Genetic variants associated with PE are located in key domains of C3 and could thereby influence the function of C3. This is, as far as we are aware, the first candidate gene in the complement system with an association to a clinically relevant PE subphenotype, severe PE. The result highlights a potential role for the complement system in the pathogenesis of PE and may help in defining prognostic and therapeutic subgroups of preeclamptic women.