Browsing by Subject "MICE"

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  • Nikkanen, Joni; Landoni, Juan Cruz; Balboa, Diego; Haugas, Maarja; Partanen, Juha; Paetau, Anders; Isohanni, Pirjo; Brilhante, Virginia; Suomalainen, Anu (2018)
    DNA polymerase gamma (POLG), the mtDNA replicase, is a common cause of mitochondrial neurodegeneration. Why POLG defects especially cause central nervous system (CNS) diseases is unknown. We discovered a complex genomic regulatory locus for POLG, containing three functional CNS-specific enhancers that drive expression specifically in oculomotor complex and sensory interneurons of the spinal cord, completely overlapping with the regions showing neuronal death in POLG patients. The regulatory locus also expresses two functional RNAs, LINC00925-RNA and MIR9-3, which are coexpressed with POLG. The MIR9-3 targets include NR2E1, a transcription factor maintaining neural stem cells in undifferentiated state, and MTHFD2, the regulatory enzyme of mitochondrial folate cycle, linking POLG expression to stem cell differentiation and folate metabolism. Our evidence suggests that distant genomic non-coding regions contribute to regulation of genes encoding mitochondrial proteins. Such genomic arrangement of POLG locus, driving expression to CNS regions affected in POLG patients, presents a potential mechanism for CNS-specific manifestations in POLG disease.
  • Kyostila, Kaisa; Syrja, Pernilla; Jagannathan, Vidhya; Chandrasekar, Gayathri; Jokinen, Tarja S; Seppala, Eija H.; Becker, Doreen; Drogemuller, Michaela; Dietschi, Elisabeth; Drogemuller, Cord; Lang, Johann; Steffen, Frank; Rohdin, Cecilia; Jaderlund, Karin H.; Lappalainen, Anu K.; Hahn, Kerstin; Wohlsein, Peter; Baumgartner, Wolfgang; Henke, Diana; Oevermann, Anna; Kere, Juha; Lohi, Hannes; Leeb, Tosso (2015)
    Inherited neurodegenerative disorders are debilitating diseases that occur across different species. We have performed clinical, pathological and genetic studies to characterize a novel canine neurodegenerative disease present in the Lagotto Romagnolo dog breed. Affected dogs suffer from progressive cerebellar ataxia, sometimes accompanied by episodic nystagmus and behavioral changes. Histological examination revealed unique pathological changes, including profound neuronal cytoplasmic vacuolization in the nervous system, as well as spheroid formation and cytoplasmic aggregation of vacuoles in secretory epithelial tissues and mesenchymal cells. Genetic analyses uncovered a missense change, c.1288G>A; p.A430T, in the autophagy-related ATG4D gene on canine chromosome 20 with a highly significant disease association (p = 3.8 x 10(-136)) in a cohort of more than 2300 Lagotto Romagnolo dogs. ATG4D encodes a poorly characterized cysteine protease belonging to themacroautophagy pathway. Accordingly, our histological analyses indicated altered autophagic flux in affected tissues. The knockdown of the zebrafish homologue atg4da resulted in a widespread developmental disturbance and neurodegeneration in the central nervous system. Our study describes a previously unknown canine neurological disease with particular pathological features and implicates the ATG4D protein as an important autophagy mediator in neuronal homeostasis. The canine phenotype serves as a model to delineate the disease-causing pathological mechanism(s) and ATG4D function, and can also be used to explore treatment options. Furthermore, our results reveal a novel candidate gene for human neurodegeneration and enable the development of a genetic test for veterinary diagnostic and breeding purposes.
  • Leigh, Robert S.; Ruskoaho, Heikki J.; Kaynak, Bogac L. (2020)
    Reliable in vitro models to assess developmental toxicity of drugs and chemicals would lead to improvement in fetal safety and a reduced cost of drug development. The validated embryonic stem cell test (EST) uses cardiac differentiation of mouse embryonic stem cells (mESCs) to predict in vivo developmental toxicity, but does not take into account the stage-specific patterning of progenitor populations into anterior (ventricular) and posterior (atrial) compartments. In this study, we generated a novel dual reporter mESC line with fluorescent reporters under the control of anterior and posterior cardiac promoters. Reporter expression was observed in nascent compartments in transgenic mouse embryos, and mESCs were used to develop differentiation assays in which chemical modulators of Wnt (XAV939: 3, 10 mu M), retinoic acid (all-trans retinoic acid: 0.1, 1, 10 mu M; 9-cis retinoic acid: 0.1, 1, 10 mu M; bexarotene 0.1, 1, 10 mu M), and Tgf-beta (SB431542: 3, 10 mu M) pathways were tested for stage- and dose-dependent effects on in vitro anterior-posterior patterning. Our results suggest that with further development, the inclusion of anterior-posterior reporter expression could be part of a battery of high-throughput tests used to identify and characterize teratogens.
  • Kopasz, Anna Georgina; Pusztai, David Zsolt; Karkas, Reka; Hudoba, Liza; Abdullah, Khaldoon Sadiq Ahmed; Imre, Gergely; Pankotai-Bodo, Gabriella; Migh, Ede; Nagy, Andrea; Kriston, Andras; German, Peter; Drubi, Andrea Bakne; Molnar, Anna; Fekete, Ildiko; Dani, Virag Eva; Ocsovszki, Imre; Puskas, Laszlo Geza; Horvath, Peter; Sukosd, Farkas; Mates, Lajos (2022)
    Background Understanding the contribution of gene function in distinct organ systems to the pathogenesis of human diseases in biomedical research requires modifying gene expression through the generation of gain- and loss-of-function phenotypes in model organisms, for instance, the mouse. However, methods to modify both germline and somatic genomes have important limitations that prevent easy, strong, and stable expression of transgenes. For instance, while the liver is remarkably easy to target, nucleic acids introduced to modify the genome of hepatocytes are rapidly lost, or the transgene expression they mediate becomes inhibited due to the action of effector pathways for the elimination of exogenous DNA. Novel methods are required to overcome these challenges, and here we develop a somatic gene delivery technology enabling long-lasting high-level transgene expression in the entire hepatocyte population of mice. Results We exploit the fumarylacetoacetate hydrolase (Fah) gene correction-induced regeneration in Fah-deficient livers, to demonstrate that such approach stabilizes luciferase expression more than 5000-fold above the level detected in WT animals, following plasmid DNA introduction complemented by transposon-mediated chromosomal gene transfer. Building on this advancement, we created a versatile technology platform for performing gene function analysis in vivo in the mouse liver. Our technology allows the tag-free expression of proteins of interest and silencing of any arbitrary gene in the mouse genome. This was achieved by applying the HADHA/B endogenous bidirectional promoter capable of driving well-balanced bidirectional expression and by optimizing in vivo intronic artificial microRNA-based gene silencing. We demonstrated the particular usefulness of the technology in cancer research by creating a p53-silenced and hRas G12V-overexpressing tumor model. Conclusions We developed a versatile technology platform for in vivo somatic genome editing in the mouse liver, which meets multiple requirements for long-lasting high-level transgene expression. We believe that this technology will contribute to the development of a more accurate new generation of tools for gene function analysis in mice.
  • Baronio, Diego; Chen, Yu-Chia; Panula, Pertti (2022)
    Monoamine oxidase (MAO) deficiency and imbalanced levels of brain monoamines have been associated with developmental delay, neuropsychiatric disorders and aggressive behavior. Animal models are valuable tools to gain mechanistic insight into outcomes associated with MAO deficiency. Here, we report a novel genetic model to study the effects of mao loss of function in zebrafish. Quantitative PCR, in situ hybridization and immunocytochemistry were used to study neurotransmitter systems and expression of relevant genes for brain development in zebrafish mao mutants. Larval and adult fish behavior was evaluated through different tests. Stronger serotonin immunoreactivity was detected in mao(+/-) and mao(-/-) larvae compared with their mao(+/+) siblings. mao(-/-) larvae were hypoactive, and presented decreased reactions to visual and acoustic stimuli. They also had impaired histaminergic and dopaminergic systems, abnormal expression of developmental markers and died within 20 days post-fertilization. mao(+/-) fish were viable, grew until adulthood, and demonstrated anxiety-like behavior and impaired social interactions compared with adult mao(+/+) siblings. Our results indicate that mao(-/-) and mao(+/-) mutants could be promising tools to study the roles of MAO in brain development and behavior.
  • Rademakers, Timo; van der Vorst, Emiel P. C.; Daissormont, Isabelle T. M. N.; Otten, Jeroen J. T.; Theodorou, Kosta; Theelen, Thomas L.; Gijbels, Marion; Anisimov, Andrey; Nurmi, Harri; Lindeman, Jan H. N.; Schober, Andreas; Heeneman, Sylvia; Alitalo, Kari; Biessen, Erik A. L. (2017)
    During plaque progression, inflammatory cells progressively accumulate in the adventitia, paralleled by an increased presence of leaky vasa vasorum. We here show that next to vasa vasorum, also the adventitial lymphatic capillary bed is expanding during plaque development in humans and mouse models of atherosclerosis. Furthermore, we investigated the role of lymphatics in atherosclerosis progression. Dissection of plaque draining lymph node and lymphatic vessel in atherosclerotic ApoE(-/-)mice aggravated plaque formation, which was accompanied by increased intimal and adventitial CD3(+) T cell numbers. Likewise, inhibition of VEGF-C/D dependent lymphangiogenesis by AAV aided gene transfer of hVEGFR3-Ig fusion protein resulted in CD3(+) T cell enrichment in plaque intima and adventitia. hVEGFR3-Ig gene transfer did not compromise adventitial lymphatic density, pointing to VEGF-C/D independent lymphangiogenesis. We were able to identify the CXCL12/CXCR4 axis, which has previously been shown to indirectly activate VEGFR3, as a likely pathway, in that its focal silencing attenuated lymphangiogenesis and augmented T cell presence. Taken together, our study not only shows profound, partly CXCL12/CXCR4 mediated, expansion of lymph capillaries in the adventitia of atherosclerotic plaque in humans and mice, but also is the first to attribute an important role of lymphatics in plaque T cell accumulation and development.
  • Licht, Tamar; Kreisel, Tirzah; Biala, Yoav; Mohan, Sandesh; Yaari, Yoel; Anisimov, Andrey; Alitalo, Kari; Keshet, Eli (2020)
    Multiple insults to the brain lead to neuronal cell death, thus raising the question to what extent can lost neurons be replenished by adult neurogenesis. Here we focused on the hippocampus and especially the dentate gyrus (DG), a vulnerable brain region and one of the two sites where adult neuronal stem cells (NSCs) reside. While adult hippocampal neurogenesis was extensively studied with regard to its contribution to cognitive enhancement, we focused on their underestimated capability to repair a massively injured, nonfunctional DG. To address this issue, we inflicted substantial DG-specific damage in mice of either sex either by diphtheria toxin-based ablation of >50% of mature DG granule cells (GCs) or by prolonged brain-specific VEGF overexpression culminating in extensive, highly selective loss of DG GCs (thereby also reinforcing the notion of selective DG vulnerability). The neurogenic system promoted effective regeneration by increasing NSCs proliferation/survival rates, restoring a nearly original DG mass, promoting proper rewiring of regenerated neurons to their afferent and efferent partners, and regaining of lost spatial memory. Notably, concomitantly with the natural age-related decline in the levels of neurogenesis, the regenerative capacity of the hippocampus also subsided with age. The study thus revealed an unappreciated regenerative potential of the young DG and suggests hippocampal NSCs as a critical reservoir enabling recovery from catastrophic DG damage.
  • Huck, Olivier; Mulhall, Hannah; Rubin, George; Kizelnik, Zev; Iyer, Radha; Perpich, John D; Haque, Nasreen; Cani, Patrice D; de Vos, Willem M; Amar, Salomon (2020)
    Abstract Aim Akkermansia muciniphila is a beneficial gut commensal, whose anti-inflammatory properties have recently been demonstrated. This study aimed to evaluate the effect of A.muciniphila on Porphyromonas gingivalis elicited inflammation. Material and Methods In lean and obese mice, A.muciniphila was administered in P.gingivalis induced calvarial abcess and in experimental periodontitis model (EIP). Bone destruction and inflammation were evaluated by histomorphometric analysis. In vitro, A.muciniphila was co-cultured with P.gingivalis, growth and virulence factors expression were evaluated. Bone-marrow macrophages (BMM?) and gingival epithelial cells (TIGK) were exposed to both bacterial strains and the expression of inflammatory mediators, as well as tight junction markers was analyzed. Results In a model of calvarial infection, A.muciniphila decreased inflammatory cell infiltration and bone destruction. In EIP, treatment with A.muciniphila resulted in a decreased alveolar bone loss. In vitro, the addition of A.muciniphila to P.gingivalis infected BMM? increased anti-inflammatory IL-10 and decreased IL-12. Additionally, A.muciniphila exposure increases the expression of junctional integrity markers such as integrin-?1, E-cadherin and ZO-1 in TIGK cells. A.muciniphila co-culture with P.gingivalis reduced gingipains mRNA expression. Discussion This study demonstrated the protective effects of A.muciniphila administration and may open consideration to its use as an adjunctive therapeutic agent to periodontal treatment.
  • Sironen, Anu; Uimari, Pekka; Venhoranta, Heli; Andersson, Magnus; Vilkki, Johanna (2011)
    ABSTRACT: BACKGROUND: Male infertility is an increasing problem in all domestic species including man. Localization and identification of genes involved in defects causing male infertility provide valuable information of specific events in sperm development. Sperm development is a complex process, where diploid spermatogonia develop into haploid, highly specialized spermatozoa. Correct expression and function of various genes and their protein products are required for production of fertile sperm. We have identified an infertility defect in Finnish Yorkshire boars caused by spermatogenic arrest. The aim of this study was to locate the disease associated region using genome wide screen with the PorcineSNP60 Beadchip and identify the causal mutation by candidate gene approach. RESULTS: In the Finnish Yorkshire pig population the spermatogenic arrest (SA) defect appears to be of genetic origin and causes severe degeneration of germ cells and total absence of spermatozoa. Genome wide scan with the PorcineSNP60 Beadchip localized the SA defect to porcine chromosome 12 in a 2 Mbp region. Sequencing of a candidate gene Tex14 revealed a 51 bp insertion within exon 27, which caused differential splicing of the exon and created a premature translation stop codon. The expression of Tex14 was markedly down regulated in the testis of a SA affected boar compared to control boars and no protein product was identified by Western blotting. The SA insertion sequence was also found within intron 27 in all analyzed animals, thus the insertion appears to be a possible duplication event. CONCLUSION: In this study we report the identification of a causal mutation for infertility caused by spermatogenic arrest at an early meiotic phase. Our results highlight the role of TEX14 specifically in spermatogenesis and the importance of specific genomic remodeling events as causes for inherited defects.
  • Chu, Man; Li, Taotao; Shen, Bin; Cao, Xudong; Zhong, Haoyu; Zhang, Luqing; Zhou, Fei; Ma, Wenjuan; Jiang, Haijuan; Xie, Pancheng; Liu, Zhengzheng; Dong, Ningzheng; Xu, Ying; Zhao, Yun; Xu, Guoqiang; Lu, Peirong; Luo, Jincai; Wu, Qingyu; Alitalo, Kari; Koh, Gou Young; Adams, Ralf H.; He, Yulong (2016)
    Mechanisms underlying the vein development remain largely unknown. Tie2 signaling mediates endothelial cell (EC) survival and vascular maturation and its activating mutations are linked to venous malformations. Here we show that vein formation are disrupted in mouse skin and mesentery when Tie2 signals are diminished by targeted deletion of Tek either ubiquitously or specifically in embryonic ECs. Postnatal Tie2 attenuation resulted in the degeneration of newly formed veins followed by the formation of haemangioma-like vascular tufts in retina and venous tortuosity. Mechanistically, Tie2 insufficiency compromised venous EC identity, as indicated by a significant decrease of COUP-TFII protein level, a key regulator in venogenesis. Consistently, angiopoietin-1 stimulation increased COUP-TFII in cultured ECs, while Tie2 knockdown or blockade of Tie2 downstream PI3K/Akt pathway reduced COUP-TFII which could be reverted by the proteasome inhibition. Together, our results imply that Tie2 is essential for venous specification and maintenance via Akt mediated stabilization of COUP-TFII.
  • Diniz, Cassiano Ricardo Alves Faria; Casarotto, Plinio C.; Fred, Senem M.; Biojone, Caroline; Castrén, Eero; Joca, Sâmia R.L. (2018)
    The renin-angiotensin system (RAS) is associated with peripheral fluid homeostasis and cardiovascular function, but recent evidence also suggests a functional role in the brain. RAS regulates physiological and behavioral parameters related to the stress response, including depressive symptoms. Apparently, RAS can modulate levels of brain-derived neurotrophic factor (BDNF) and TRKB, which are important in the neurobiology of depression and antidepressant action. However, the interaction between the BDNF/TRKB system and RAS in depression has not been investigated before. Accordingly, in the forced swimming test, we observed an antidepressant-like effect of systemic losartan but not with captopril or enalapril treatment. Moreover, infusion of losartan into the ventral hippocampus (vHC) and prelimbic prefrontal cortex (PL) mimicked the consequences of systemically injected losartan, whereas K252a (a blocker of TRK) infused into these brain areas impaired such effect. PD123319, an antagonist of AT2 receptor (AGTR2), also prevented the systemic losartan effect when infused into PL but not into vHC. Cultured cortical cells of rat embryos revealed that angiotensin II (ANG2), possibly through AGTR2, increased the surface levels of TRKB and its coupling to FYN, a SRC family kinase. Higher Agtr2 levels in cortical cells were reduced after stimulation with glutamate, and only under this condition an interaction between losartan and ANG2 was achieved. TRKB/AGTR2 heterodimers were also observed, in MG87 cells GFP-tagged AGTR2 co-immunoprecipitated with TRKB. Therefore, the antidepressant-like effect of losartan is proposed to occur through a shift of ANG2 towards AGTR2, followed by coupling of TRK/FYN and putative TRIG transactivation. Thus, the blockade of AGTR1 has therapeutic potential as a novel antidepressant therapy. (C) 2018 The Author(s). Published by Elsevier Ltd.
  • Pohjanvirta, Raimo; Mahiout, Selma (2019)
    Previous studies have shown that several aryl hydrocarbon receptor (AHR) agonists, including β-naphthoflavone (BNF), elicit avoidance of novel food items in rodents, with this behavioral response displaying a similar doseresponse to hepatic induction of CYP1A1. The avoidance has been found to bear substantial similarity to conditioned taste avoidance/aversion (CTA). The present study set out to confirm the indispensability of AHR in the avoidance response, to verify whether vagal afferent fibers are involved in it, and to see if AHR signaling might interfere with the effect of the classic trigger of CTA, LiCl. To this end, globally AHR deficient (AHRKO) or vagotomized wildtype rats were treated by gavage with 60 mg/kg BNF or ip with 0.15M LiCl (4 ml/kg), and presented with chocolate which was either novel or familiar to them. Both the avoidance response and Cyp1a1 induction were missing in AHRKO rats. In contrast, Ahr+/− rats exhibited them in full, save for a single outlier. Total subdiaphragmatic vagotomy failed to interfere with the avoidance of novel or familiar chocolate or induction of Cyp1a1. After LiCl administration, male AHRKO rats showed a significantly mitigated suppression of chocolate consumption compared with wildtype animals (~60% vs. ~10% of control chocolate intake, respectively). A similar tendency was seen in females, but they were less responsive to LiCl. These findings corroborate AHR as a prerequisite of the BNF-induced novel food avoidance, prove vagal afferents unlikely mediators of this response, and imply an unforeseen involvement of AHR signaling in the thoroughly-characterized CTA instigated by LiCl.
  • Landolt, Lea; Furriol, Jessica; Babickova, Janka; Ahmed, Lavina; Eikrem, Oystein; Skogstrand, Trude; Scherer, Andreas; Suliman, Salwa; Leh, Sabine; Lorens, J. B.; Gausdal, Gro; Marti, H.P.; Osman, Tarig (2019)
    The AXL receptor tyrosine kinase (RTK) is involved in partial epithelial-to-mesenchymal transition (EMT) and inflammation - both main promoters of renal fibrosis development. The study aim was to investigate the role of AXL inhibition in kidney fibrosis due to unilateral ureteral obstruction (UUO). Eight weeks old male C57BL/6 mice underwent UUO and were treated with oral AXL inhibitor bemcentinib (n = 22), Angiotensin-converting enzyme inhibitor (ACEI, n = 10), ACEI and bemcentinib (n = 10) or vehicle alone (n = 22). Mice were sacrificed after 7 or 15 days and kidney tissues were analyzed by immunohistochemistry (IHC), western blot, ELISA, Sirius Red (SR) staining, and hydroxyproline (Hyp) quantification. RNA was extracted from frozen kidney tissues and sequenced on an Illumina HiSeq4000 platform. After 15 days the ligated bemcentinib-treated kidneys showed less fibrosis compared to the ligated vehicle-treated kidneys in SR analyses and Hyp quantification. Reduced IHC staining for Vimentin (VIM) and alpha smooth muscle actin (alpha SMA), as well as reduced mRNA abundance of key regulators of fibrosis such as transforming growth factor (Tgf beta), matrix metalloproteinase 2 (Mmp2), Smad2, Smad4, myofibroblast activation (Aldh1a2, Crlf1), and EMT (Snai1,2, Twist), in ligated bemcentinib-treated kidneys was compatible with reduced (partial) EMT induction. Furthermore, less F4/80 positive cells, less activity of pathways related to the immune system and lower abundance of MCP1, MCP3, MCP5, and TARC in ligated bemcentinib-treated kidneys was compatible with reduction in inflammatory infiltrates by bemcentinib treatment. The AXL RTK pathway represents a promising target for pharmacologic therapy of kidney fibrosis.
  • Kilpeläinen, Tommi; Julku, Ulrika; Svarcbahs, Reinis; Myöhänen, Timo (2019)
    Alpha-synuclein (aSyn) is the main component of Lewy bodies, the histopathological marker in Parkinson's disease (PD), and point mutations and multiplications of the aSyn coding SNCA gene correlate with early onset PD. Therefore, various transgenic mouse models overexpressing native or point-mutated aSyn have been developed. Although these models show highly increased aSyn expression they rarely capture dopaminergic cell loss and show a behavioural phenotype only at old age, whereas SNCA mutations are risk factors for PD with earlier onset. The aim of our study was to re-characterize a transgenic mouse strain carrying both A30P and A53T mutated human aSyn. Our study revealed decreased locomotor activity for homozygous transgenic mice starting from 3 months of age which was different from previous studies with this mouse strain that had behavioural deficits starting only after 7-9 months. Additionally, we found a decreased amphetamine response in locomotor activity and decreased extracellular dopaminergic markers in the striatum and substantia nigra with significantly elevated levels of aSyn oligomers. In conclusion, homozygous transgenic A30P*A53T aSyn mice capture several phenotypes of PD with early onset and could be a useful tool for aSyn studies.
  • Muona, Mikko; Ishimura, Ryosuke; Laari, Anni; Ichimura, Yoshinobu; Linnankivi, Tarja; Keski-Filppula, Riikka; Herva, Riitta; Rantala, Heikki; Paetau, Anders; Pöyhönen, Minna; Obata, Miki; Uemura, Takefumi; Karhu, Thomas; Bizen, Norihisa; Takebayashi, Hirohide; McKee, Shane; Parker, Michael J.; Akawi, Nadia; McRae, Jeremy; Hurles, Matthew E.; Kuismin, Outi; Kurki, Mitja I.; Anttonen, Anna-Kaisa; Tanaka, Keiji; Palotie, Aarno; Waguri, Satoshi; Lehesjoki, Anna-Elina; Komatsus, Masaaki; DDD Study (2016)
    The ubiquitin fold modifier 1 (UFM1) cascade is a recently identified evolutionarily conserved ubiquitin-like modification system whose function and link to human disease have remained largely uncharacterized. By using exome sequencing in Finnish individuals with severe epileptic syndromes, we identified pathogenic compound heterozygous variants in UBAS, encoding an activating enzyme for UFM1, in two unrelated families. Two additional individuals with biallelic UBAS variants were identified from the UK-based Deciphering Developmental Disorders study and one from the Northern Finland Intellectual Disability cohort. The affected individuals (n = 9) presented in early infancy with severe irritability, followed by dystonia and stagnation of development. Furthermore, the majority of individuals display postnatal microcephaly and epilepsy and develop spasticity. The affected individuals were compound heterozygous for a missense substitution, c.1111G>A (p.A1a371Thr; allele frequency of 0.28% in Europeans), and a nonsense variant or c.164G>A that encodes an amino acid substitution p.Arg5SHis, but also affects splicing by facilitating exon 2 skipping, thus also being in effect a loss-of-function allele. Using an in vitro thioester formation assay and cellular analyses, we show that the p.A1a371Thr variant is hypomorphic with attenuated ability to transfer the activated UFM1 to UFC1. Finally, we show that the CNS-specific knockout of Ufml in mice causes neonatal death accompanied by microcephaly and apoptosis in specific neurons, further suggesting that the UFM1 system is essential for CNS development and function. Taken together, our data imply that the combination of a hypomorphic p.A1a371Thr variant in trans with a loss-of-function allele in UBAS underlies a severe infantile-onset encephalopathy.
  • Karvinen, Sira; Fachada, Vasco; Sahinaho, Ulla-Maria; Pekkala, Satu; Lautaoja, Juulia H.; Mäntyselkä, Sakari; Permi, Perttu; Hulmi, Juha J.; Silvennoinen, Mika; Kainulainen, Heikki (2022)
    Impaired lipid metabolism is a common risk factor underlying several metabolic diseases such as metabolic syndrome and type 2 diabetes. Branched-chain amino acids (BCAAs) that include valine, leucine and isoleucine have been proven to share a role in lipid metabolism and hence in maintaining metabolic health. We have previously introduced a hypothesis suggesting that BCAA degradation mechanistically connects to lipid oxidation and storage in skeletal muscle. To test our hypothesis, the present study examined the effects of BCAA deprivation and supplementation on lipid oxidation, lipogenesis and lipid droplet characteristics in murine C2C12 myotubes. In addition, the role of myotube contractions on cell metabolism was studied by utilizing in vitro skeletal-muscle-specific exercise-like electrical pulse stimulation (EPS). Our results showed that the deprivation of BCAAs decreased both lipid oxidation and lipogenesis in C2C12 myotubes. BCAA deprivation further diminished the number of lipid droplets in the EPS-treated myotubes. EPS decreased lipid oxidation especially when combined with high BCAA supplementation. Similar to BCAA deprivation, high BCAA supplementation also decreased lipid oxidation. The present results highlight the role of an adequate level of BCAAs in healthy lipid metabolism.
  • Gu, Yuexi; Helenius, Mikko; Vaananen, Kristiina; Bulanova, Daria; Saarela, Jani; Sokolenko, Anna; Martens, John; Imyanitov, Evgeny; Kuznetsov, Sergey (2016)
    Germ-line or somatic inactivation of BRCA1 is a defining feature for a portion of human breast cancers. Here we evaluated the anti-proliferative activity of 198 FDA-approved and experimental drugs against four BRCA1-mutant (HCC1937, MDA-MB-436, SUM1315MO2, and SUM149PT) and four BRCA1-wild-type (MDA-MB-231, SUM229PE, MCF10A, and MCF7) breast cancer cell lines. We found that all BRCA1-mutant cell lines were insensitive to inhibitors of mitogen-activated protein kinase kinase 1 and 2 (MEK1/2) Selumetinib and Pimasertib in contrast to BRCA1-wildtype control cell lines. However, unexpectedly, only two BRCA1-mutant cell lines, HCC1937 and MDA-MB-436, were hypersensitive to a nucleotide analogue 6-thioguanine (6-TG). SUM149PT cells readily formed radiation-induced RAD51-positive nuclear foci indicating a functional homologous recombination, which may explain their resistance to 6-TG. However, the reason underlying 6-TG resistance of SUM1315MO2 cells remains unclear. Our data reveal a remarkable heterogeneity among BRCA1-mutant cell lines and provide a reference for future studies.
  • Szibor, Marten; Dhandapani, Praveen K.; Dufour, Eric; Holmstrom, Kira M.; Zhuang, Yuan; Salwig, Isabelle; Wittig, Ilka; Heidler, Juliana; Gizatullina, Zemfira; Gainutdinov, Timur; Fuchs, Helmut; Gailus-Durner, Valerie; de Angelis, Martin Hrabe; Nandania, Jatin; Velagapudi, Vidya; Wietelmann, Astrid; Rustin, Pierre; Gellerich, Frank N.; Jacobs, Howard T.; Braun, Thomas; German Mouse Clinic Consortium (2017)
    Plants and many lower organisms, but not mammals, express alternative oxidases (AOXs) that branch the mitochondrial respiratory chain, transferring electrons directly from ubiquinol to oxygen without proton pumping. Thus, they maintain electron flow under conditions when the classical respiratory chain is impaired, limiting excess production of oxygen radicals and supporting redox and metabolic homeostasis. AOX from Ciona intestinalis has been used to study and mitigate mitochondrial impairments in mammalian cell lines, Drosophila disease models and, most recently, in the mouse, where multiple lentivector-AOX transgenes conferred substantial expression in specific tissues. Here, we describe a genetically tractable mouse model in which Ciona AOX has been targeted to the Rosa26 locus for ubiquitous expression. The AOX(Rosa26) mouse exhibited only subtle phenotypic effects on respiratory complex formation, oxygen consumption or the global metabolome, and showed an essentially normal physiology. AOX conferred robust resistance to inhibitors of the respiratory chain in organello; moreover, animals exposed to a systemically applied LD50 dose of cyanide did not succumb. The AOX(Rosa26) mouse is a useful tool to investigate respiratory control mechanisms and to decipher mitochondrial disease aetiology in vivo.
  • Landberg, Niklas; von Palffy, Sofia; Askmyr, Maria; Lilljebjorn, Henrik; Sanden, Carl; Rissler, Marianne; Mustjoki, Satu; Hjorth-Hansen, Henrik; Richter, Johan; Agerstam, Helena; Jaras, Marcus; Fioretos, Thoas (2018)
    Tyrosine kinase inhibitors (TKIs) are highly effective for the treatment of chronic myeloid leukemia (CML), but very few patients are cured. The major drawbacks regarding TKIs are their low efficacy in eradicating the leukemic stem cells responsible for disease maintenance and relapse upon drug cessation. Herein, we performed ribonucleic acid sequencing of flow-sorted primitive (CD34(+) CD38(low)) and progenitor (CD34(+) CD38(+)) chronic phase CML cells, and identified transcriptional upregulation of 32 cell surface molecules relative to corresponding normal bone marrow cells. Focusing on novel markers with increased expression on primitive CML cells, we confirmed upregulation of the scavenger receptor CD36 and the leptin receptor by flow cytometry. We also delineate a subpopulation of primitive CML cells expressing CD36 that is less sensitive to imatinib treatment. Using CD36 targeting anti-bodies, we show that the CD36 positive cells can be targeted and killed by antibody-dependent cellular cytotoxicity. In summary, CD36 defines a subpopulation of primitive CML cells with decreased imatinib sensitivity that can be effectively targeted and killed using an anti-CD36 anti-body.