Publications by authors named "Ori Brenner"

62 Publications

BCKDK regulates the TCA cycle through PDC in the absence of PDK family during embryonic development.

Dev Cell 2021 Apr 26;56(8):1182-1194.e6. Epub 2021 Mar 26.

Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel. Electronic address:

Pyruvate dehydrogenase kinases (PDK1-4) inhibit the TCA cycle by phosphorylating pyruvate dehydrogenase complex (PDC). Here, we show that PDK family is dispensable for murine embryonic development and that BCKDK serves as a compensatory mechanism by inactivating PDC. First, we knocked out all four Pdk genes one by one. Surprisingly, Pdk total KO embryos developed and were born in expected ratios but died by postnatal day 4 because of hypoglycemia or ketoacidosis. Moreover, PDC was phosphorylated in these embryos, suggesting that another kinase compensates for PDK family. Bioinformatic analysis implicated branched-chain ketoacid dehydrogenase kinase (Bckdk), a key regulator of branched-chain amino acids (BCAAs) catabolism. Indeed, knockout of Bckdk and Pdk family led to the loss of PDC phosphorylation, an increase in PDC activity and pyruvate entry into the TCA cycle, and embryonic lethality. These findings reveal a regulatory crosstalk hardwiring BCAA and glucose catabolic pathways, which feed the TCA cycle.
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http://dx.doi.org/10.1016/j.devcel.2021.03.007DOI Listing
April 2021

A tecpr2 knockout mouse exhibits age-dependent neuroaxonal dystrophy associated with autophagosome accumulation.

Autophagy 2020 Dec 10:1-14. Epub 2020 Dec 10.

Departments of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.

Mutations in the coding sequence of human were recently linked to spastic paraplegia type 49 (SPG49), a hereditary neurodegenerative disorder involving intellectual disability, autonomic-sensory neuropathy, chronic respiratory disease and decreased pain sensitivity. Here, we report the generation of a novel CRISPR-Cas9 knockout () mouse that exhibits behavioral pathologies observed in SPG49 patients. mice develop neurodegenerative patterns in an age-dependent manner, manifested predominantly as neuroaxonal dystrophy in the gracile (GrN) and cuneate nuclei (CuN) of the medulla oblongata in the brainstem and dorsal white matter column of the spinal cord. Age-dependent correlation with accumulation of autophagosomes suggests compromised targeting to lysosome. Taken together, our findings establish the knockout mouse as a potential model for SPG49 and ascribe a new role to TECPR2 in macroautophagy/autophagy-related neurodegenerative disorders.
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http://dx.doi.org/10.1080/15548627.2020.1852724DOI Listing
December 2020

Titration of myelin oligodendrocyte glycoprotein (MOG) - Induced experimental autoimmune encephalomyelitis (EAE) model.

J Neurosci Methods 2021 03 12;351:108999. Epub 2020 Nov 12.

Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel. Electronic address:

Background: Experimental autoimmune encephalomyelitis (EAE) induced by the myelin oligodendrocyte glycoprotein (MOG) peptide 35-55, is a widely used multiple sclerosis (MS) model. Unlike the spontaneous occurrence of MS, in EAE, external immunization with the MOG peptide (200-300 µg/mouse), emulsified in adjuvant enriched with Mycobacterium Tuberculosis (MT) H37Ra (100-500 µg mouse), and pertussis toxin (PTx, 200-500 ng/mouse) injections, are applied, which heavily boosts the immune system.

New Method: A detailed and systematic titration of the MOG 35-55 EAE induction protocol in C57BL/6 mice reveals the minimal doses of the MOG 35-55 peptide, MT H37Ra, and PTx, required for disease manifestation.

Results: The amounts of MOG 35-55 peptide, MT H37Ra, and PTx can be drastically reduced from the standard protocol, to level of 5 µg MOG, 25 µg MT H37Ra, and 50 ng PTx, without affecting the clinical manifestations. The titrated protocols induced a high disease incidence and a consistent robust disease course, with full histopathological characteristics of the MOG model, inflammation, demyelination and axonal damage.

Comparison With Existing Methods: Similar disease incidences, day of symptoms appearance, maximal clinical score, and histopathology were obtained for the standard and the titrated protocols.

Conclusions: Reducing the reagent dosages used for EAE induction, without attenuating the disease, can give a truer and less artificial perspective of MS. We propose an improved protocol for this extensively used model, with high disease incidence, a consistent robust course, and characteristic histological manifestations, which may be more sensitive for testing therapeutic modalities, cost-effective, and less distressing to the animals.
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http://dx.doi.org/10.1016/j.jneumeth.2020.108999DOI Listing
March 2021

Brain pathology and cerebellar purkinje cell loss in a mouse model of chronic neuronopathic Gaucher disease.

Prog Neurobiol 2021 02 3;197:101939. Epub 2020 Nov 3.

Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.

Gaucher disease (GD) is currently the focus of considerable attention due primarily to the association between the gene that causes GD (GBA) and Parkinson's disease. Mouse models exist for the systemic (type 1) and for the acute neuronopathic forms (type 2) of GD. Here we report the generation of a mouse that phenotypically models chronic neuronopathic type 3 GD. Gba;Gba mice, which contain a Gba transgene regulated by doxycycline, accumulate moderate levels of the offending substrate in GD, glucosylceramide, and live for up to 10 months, i.e. significantly longer than mice which model type 2 GD. Gba;Gba mice display behavioral abnormalities at ∼4 months, which deteriorate with age, along with significant neuropathology including loss of Purkinje neurons. Gene expression is altered in the brain and in isolated microglia, although the changes in gene expression are less extensive than in mice modeling type 2 disease. Finally, bone deformities are consistent with the Gba;Gba mice being a genuine type 3 GD model. Together, the Gba;Gba mice share pathological pathways with acute neuronopathic GD mice but also display differences that might help understand the distinct disease course and progression of type 2 and 3 patients.
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http://dx.doi.org/10.1016/j.pneurobio.2020.101939DOI Listing
February 2021

Obstructive fibrinous tracheal pseudomembrane in a cat.

J Vet Intern Med 2020 Nov 24;34(6):2687-2690. Epub 2020 Oct 24.

Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel.

Tracheal intubation (TI) is a common procedure that rarely entails life-threatening complications. A 1.5-year-old female spayed cat presented with acute signs of respiratory distress 5 weeks after undergoing TI. Radiographs revealed a marked, segmental, tracheal narrowing. A hard, 5-cm-long, white-yellowish tissue was identified and removed from the trachea, with subsequent resolution of clinical signs and radiographic changes. Microscopically, the tissue consisted of fibrin and lytic neutrophils, interspaced with optically empty cavities and a few remains of talcum powder and hair shafts. Consequently, a diagnosis of obstructive fibrinous tracheal pseudomembrane (OFTP) was made. A rare complication of TI in humans, OFTP should also be suspected in cats with respiratory distress, a history of TI and radiographic evidence of tracheal narrowing. Based on cases from other species and the cat described herein, the condition can be easily resolved with OFTP removal.
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http://dx.doi.org/10.1111/jvim.15944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694847PMC
November 2020

Runx3 prevents spontaneous colitis by directing the differentiation of anti-inflammatory mononuclear phagocytes.

PLoS One 2020 26;15(5):e0233044. Epub 2020 May 26.

Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel.

Mice deficient in the transcription factor Runx3 develop a multitude of immune system defects, including early onset colitis. This paper demonstrates that Runx3 is expressed in colonic mononuclear phagocytes (MNP), including resident macrophages (RM) and dendritic cell subsets (cDC2). Runx3 deletion in MNP causes early onset colitis due to their impaired maturation. Mechanistically, the resulting MNP subset imbalance leads to up-regulation of pro-inflammatory genes as occurs in IL10R-deficient RM. In addition, RM and cDC2 display a marked decrease in expression of anti-inflammatory/TGF β-regulated genes and β-catenin signaling associated genes, respectively. MNP transcriptome and ChIP-seq data analysis suggest that a significant fraction of genes affected by Runx3 loss are direct Runx3 targets. Collectively, Runx3 imposes intestinal immune tolerance by regulating maturation of colonic anti-inflammatory MNP, befitting the identification of RUNX3 as a genome-wide associated risk gene for various immune-related diseases in humans, including gastrointestinal tract diseases such as Crohn's disease and celiac.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233044PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7250423PMC
July 2020

Massive osteopetrosis caused by non-functional osteoclasts in R51Q SNX10 mutant mice.

Bone 2020 07 8;136:115360. Epub 2020 Apr 8.

Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address:

The R51Q mutation in sorting nexin 10 (SNX10) was shown to cause a lethal genetic disease in humans, namely autosomal recessive osteopetrosis (ARO). We describe here the first R51Q SNX10 knock-in mouse model and show that mice homozygous for this mutation exhibit massive, early-onset, and widespread osteopetrosis. The mutant mice exhibit multiple additional characteristics of the corresponding human disease, including stunted growth, failure to thrive, missing or impacted teeth, occasional osteomyelitis, and a significantly-reduced lifespan. Osteopetrosis in this model is the result of osteoclast inactivity that, in turn, is caused by absence of ruffled borders in the mutant osteoclasts and by their inability to secrete protons. These results confirm that the R51Q mutation in SNX10 is a causative factor in ARO and provide a model system for studying this rare disease.
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http://dx.doi.org/10.1016/j.bone.2020.115360DOI Listing
July 2020

Murine and related chapparvoviruses are nephro-tropic and produce novel accessory proteins in infected kidneys.

PLoS Pathog 2020 01 23;16(1):e1008262. Epub 2020 Jan 23.

Lowy Cancer Research Centre, University of New South Wales Sydney, Sydney, NSW, Australia.

Mouse kidney parvovirus (MKPV) is a member of the provisional genus Chapparvovirus that causes renal disease in immune-compromised mice, with a disease course reminiscent of polyomavirus-associated nephropathy in immune-suppressed kidney transplant patients. Here we map four major MKPV transcripts, created by alternative splicing, to a common initiator region, and use mass spectrometry to identify "p10" and "p15" as novel chapparvovirus accessory proteins produced in MKPV-infected kidneys. p15 and the splicing-dependent putative accessory protein NS2 are conserved in all near-complete amniote chapparvovirus genomes currently available (from mammals, birds and a reptile). In contrast, p10 may be encoded only by viruses with >60% amino acid identity to MKPV. We show that MKPV is kidney-tropic and that the bat chapparvovirus DrPV-1 and a non-human primate chapparvovirus, CKPV, are also found in the kidneys of their hosts. We propose, therefore, that many mammal chapparvoviruses are likely to be nephrotropic.
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http://dx.doi.org/10.1371/journal.ppat.1008262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6999912PMC
January 2020

Aberrant Mesenteric Migration of Larvae Causing Necrotizing Eosinophilic Arteritis, Thrombosis, and Intestinal Infarction in Dogs.

Vet Pathol 2020 03 25;57(2):281-285. Epub 2019 Nov 25.

Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel.

This report presents a novel canine condition in 32 dogs in which aberrant migration of larvae through mesenteric arteries, instead of gastric arteries, led to small or large intestinal infarction. This form of spirocercosis was first recognized in Israel in 2013 and is currently ongoing. Typical clinical signs were anorexia and weakness of 3 to 4 days and, less frequently, vomiting and diarrhea, followed by collapse, bloody diarrhea, and severe vomiting. Exploratory laparotomy showed 1 or more infarcted and often perforated intestinal segments in all cases. Microscopically, there was intestinal mucosal to transmural coagulative necrosis and mesenteric multifocal necrotizing eosinophilic arteritis, thrombosis, hemorrhage, and early fibroplasia. Third-stage larvae were identified by morphologic features in 9 of 32 (28%) cases, and the species was confirmed by polymerase chain reaction in 4 cases. Nearly 50% of the dogs had been receiving prophylactic therapy, which did not prevent this form of spirocercosis.
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http://dx.doi.org/10.1177/0300985819887531DOI Listing
March 2020

Clinical characteristics of Spirocerca lupi migration in the spinal cord.

Vet Parasitol 2018 Apr 15;253:16-21. Epub 2018 Feb 15.

Koret School of Veterinary Medicine, Veterinary Teaching Hospital, Hebrew University of Jerusalem, P.O. Box 12, Rehovot, 76100, Israel.

Spirocerca lupi is a nematode infecting dogs mostly in tropical and subtropical areas. Although its typical target is the esophageal wall, aberrant migration is not uncommon, including migration of unknown incidence into the spinal cord. While successful treatment of intraspinal S. lupi (ISSL) infection depends on early diagnosis, tools for definitive ante-mortem diagnosis are unavailable. We therefore aimed at characterizing clinical signs and clinical pathology findings of ISSL in dogs. For that, we analyzed medical records of dogs hospitalized in 2005-2016 presenting with neurological signs consistent with ISSL, which were diagnosed definitively post-mortem. Retrieved information included signalment, medical history, chief complaint, physical and neurological evaluation, neuroanatomical localization at presentation, clinical pathology, imaging findings, treatment, outcome and post-mortem findings. Ten midsize to large breed dogs were included, 7 of which had received prophylactic treatment. In all 10 dogs, onset was acute and neurological deterioration until presentation (2 h-6 d) was fast. Neurological examination localized the lesions within the spinal cord and paresis or paralysis was asymmetric in all dogs. Spinal pain was documented in 9/10 dogs. Cerebrospinal fluid (CSF) analysis was abnormal in all dogs and was characterized by pleocytosis in 8/10, whereas cytology revealed the presence of eosinophils in all dogs. Advanced imaging excluded spinal cord compression in all dogs tested. Post-mortem examination detected spinal cord migration tract in all cases. Nematodes were found in the spinal cord parenchyma (8/10) or adjacent to it (2/10) in all dogs. A larva was found in the subarachnoid space of one dog and an adult nematode in the thoracic intervertebral artery of another. Esophageal nodules were found in 5/10 dogs. These findings suggest that the combination of sudden onset of acute asymmetric paresis accompanied by pain, presence of eosinophils in the CSF and lack of compressive lesion may serve as sufficient evidence for tentative diagnosis of ISSL in endemic areas.
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http://dx.doi.org/10.1016/j.vetpar.2018.02.025DOI Listing
April 2018

Loss of forebrain MTCH2 decreases mitochondria motility and calcium handling and impairs hippocampal-dependent cognitive functions.

Sci Rep 2017 03 9;7:44401. Epub 2017 Mar 9.

Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel.

Mitochondrial Carrier Homolog 2 (MTCH2) is a novel regulator of mitochondria metabolism, which was recently associated with Alzheimer's disease. Here we demonstrate that deletion of forebrain MTCH2 increases mitochondria and whole-body energy metabolism, increases locomotor activity, but impairs motor coordination and balance. Importantly, mice deficient in forebrain MTCH2 display a deficit in hippocampus-dependent cognitive functions, including spatial memory, long term potentiation (LTP) and rates of spontaneous excitatory synaptic currents. Moreover, MTCH2-deficient hippocampal neurons display a deficit in mitochondria motility and calcium handling. Thus, MTCH2 is a critical player in neuronal cell biology, controlling mitochondria metabolism, motility and calcium buffering to regulate hippocampal-dependent cognitive functions.
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http://dx.doi.org/10.1038/srep44401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5343590PMC
March 2017

Leishmania major infection in a dog with cutaneous manifestations.

Parasit Vectors 2016 05 10;9(1):246. Epub 2016 May 10.

School of Veterinary Medicine, Hebrew University, P.O. Box 12, Rehovot, 76100, Israel.

Background: Leishmania major is a main cause of cutaneous leishmaniasis in humans in an area that stretches from India through Central Asia, the Middle East, to North and West Africa. In Israel, it is a common infection of humans with rodents as the reservoir hosts and Phlebotomus papatasi as its sand fly vector.

Findings: A 6 months old spayed female mixed breed dog was referred to the Hebrew University Veterinary Teaching Hospital with a large ulcerative dermal lesion on the muzzle, and lesions in the foot pads and left hind leg. Histopathology of a skin biopsy found chronic lymphohistiocytic dermatitis with the presence of Leishmania spp. amastigotes in the muzzle. Physical examination indicated that the dog was overall in a good clinical condition and the main findings were the skin lesions and enlarged prescapular lymph nodes. Complete blood count and serum biochemistry profile were within reference ranges. Serology by ELISA was positive for Leishmania spp. and PCR of the prescapular lymph node was positive by an ITS1 region PCR-high resolution melt analysis. However, the melt curve and subsequent DNA sequencing indicated that infection was caused by L. major and not L. infantum, which is the main causative agent of canine leishmaniosis in the Mediterranean region. DNA was extracted from the paraffin embedded muzzle biopsy and PCR with sequencing also indicated L. major. The dog's young age and the absence of hyperglobulinemia and anemia were not typical of L. infantum infection. The dog was treated with allopurinol and the skin lesions improved and later disappeared when the dog was re-evaluated.

Conclusions: This is the first molecularly-confirmed case of L. major infection in a dog. Two previous reports of L. major in dogs originated from Saudi-Arabia and Egypt in 1985 and 1987 were confirmed by enzymatic biochemical techniques. Serology for L. infantum was positive probably due to the well documented serological cross-reactivity between Leishmania spp. Although dogs and wild carnivores are not considered main reservoirs for L. major, the possibility of clinical canine disease and their potential as secondary hosts should be investigated in areas endemic for human L. major infection.
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http://dx.doi.org/10.1186/s13071-016-1541-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4862095PMC
May 2016

Neutralization of pro-inflammatory monocytes by targeting TLR2 dimerization ameliorates colitis.

EMBO J 2016 Mar 15;35(6):685-98. Epub 2016 Feb 15.

Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel

Monocytes have emerged as critical driving force of acute inflammation. Here, we show that inhibition of Toll-like receptor 2(TLR2) dimerization by a TLR2 transmembrane peptide (TLR2-p) ameliorated DSS-induced colitis by interfering specifically with the activation of Ly6C(+) monocytes without affecting their recruitment to the colon. We report that TLR2-p directly interacts with TLR2 within the membrane, leading to inhibition of TLR2-TLR6/1 assembly induced by natural ligands. This was associated with decreased levels of extracellular signal-regulated kinases (ERK) signaling and reduced secretion of pro-inflammatory cytokines, such as interleukin (IL)-6, IL-23, IL-12, and IL-1β. Altogether, our study provides insights into the essential role of TLR2 dimerization in the activation of pathogenic pro-inflammatory Ly6C(hi) monocytes and suggests that inhibition of this aggregation by TLR2-p might have therapeutic potential in the treatment of acute gut inflammation.
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http://dx.doi.org/10.15252/embj.201592649DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4801944PMC
March 2016

Peripheral Neuritis Trauma in Pigs: A Neuropathic Pain Model.

J Pain 2016 Jan 9;17(1):36-49. Epub 2015 Oct 9.

Neurology R&D Division, MD Biosciences, Nes-Ziona, Israel. Electronic address:

Unlabelled: The use of rodents in preclinical studies has contributed greatly to our understanding of the pathophysiology of chronic neuropathic pain. These animal models are limited because of their poor clinical translation. We developed a pig model for chronic pain caused by surgically induced peripheral neuritis trauma (PNT). Seventy-five percent of the animals exhibited mechanical and tactile allodynia, which are indicative of painful neuropathy, by day 28 after surgery. Importantly, the PNT-injured pigs retained their ability to walk or to stand on their injured leg. Messenger RNA analysis of acute inflammatory cytokines calcitonin gene-related peptide and brain-derived neurotrophic factor at the site of injury suggests transient inflammation followed by a persistent high level of neurologic markers. Gabapentin and morphine effectively inhibited hypersensitivity to von Frey filaments and to feather stimuli, and reversed spontaneous pain-related behavior in a dose-related manner. No analgesic effect was detected in PNT-injured pigs after treatment with aprepitant, similar to observations in humans and contrary to observations in rodents. In conclusion, PNT-induced trauma in pigs may comprise a valid preclinical model for the study of the chronification of peripheral nerve injury and for the study of new pain therapies.

Perspective: This article presents the characterization of a new peripheral neuritis trauma (PNT) model in pigs. The pig PNT model could help close the translational gap between preclinical and clinical responses and may contribute to improved efficacy or safety of candidate drugs.
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http://dx.doi.org/10.1016/j.jpain.2015.09.011DOI Listing
January 2016

Runx1 Transcription Factor Is Required for Myoblasts Proliferation during Muscle Regeneration.

PLoS Genet 2015 Aug 14;11(8):e1005457. Epub 2015 Aug 14.

Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel.

Following myonecrosis, muscle satellite cells proliferate, differentiate and fuse, creating new myofibers. The Runx1 transcription factor is not expressed in naïve developing muscle or in adult muscle tissue. However, it is highly expressed in muscles exposed to myopathic damage yet, the role of Runx1 in muscle regeneration is completely unknown. Our study of Runx1 function in the muscle's response to myonecrosis reveals that this transcription factor is activated and cooperates with the MyoD and AP-1/c-Jun transcription factors to drive the transcription program of muscle regeneration. Mice lacking dystrophin and muscle Runx1 (mdx-/Runx1f/f), exhibit impaired muscle regeneration leading to age-dependent muscle waste, gradual decrease in motor capabilities and a shortened lifespan. Runx1-deficient primary myoblasts are arrested at cell cycle G1 and consequently differentiate. Such premature differentiation disrupts the myoblasts' normal proliferation/differentiation balance, reduces the number and size of regenerating myofibers and impairs muscle regeneration. Our combined Runx1-dependent gene expression, ChIP-seq, ATAC-seq and histone H3K4me1/H3K27ac modification analyses revealed a subset of Runx1-regulated genes that are co-occupied by MyoD and c-Jun in mdx-/Runx1f/f muscle. The data provide unique insights into the transcriptional program driving muscle regeneration and implicate Runx1 as an important participant in the pathology of muscle wasting diseases.
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http://dx.doi.org/10.1371/journal.pgen.1005457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4537234PMC
August 2015

Development of pheochromocytoma in ceramide synthase 2 null mice.

Endocr Relat Cancer 2015 Aug 25;22(4):623-32. Epub 2015 Jun 25.

Department of Biological ChemistryWeizmann Institute of Science, Rehovot 76100, IsraelDepartment of BiochemistrySchool of Medicine, Gachon University, Incheon 406-799, South KoreaDepartment of Veterinary ResourcesWeizmann Institute of Science, Rehovot 76100, IsraelMonique and Jacques Roboh Department of Genetic ResearchDepartment of Genetics and Metabolic Diseases, Hadassah, Hebrew University Medical Center, Jerusalem, IsraelSchool of Biology and Petit Institute for Bioengineering and BioscienceGeorgia Institute of Technology, Atlanta, Georgia 30332-0230, USA.

Pheochromocytoma (PCC) and paraganglioma are rare neuroendocrine tumors of the adrenal medulla and sympathetic and parasympathetic paraganglia, for which mutations in ∼15 disease-associated genes have been identified. We now document the role of an additional gene in mice, the ceramide synthase 2 (CerS2) gene. CerS2, one of six mammalian CerS, synthesizes ceramides with very-long (C22-C24) chains. The CerS2 null mouse has been well characterized and displays lesions in several organs including the liver, lung and the brain. We now demonstrate that changes in the sphingolipid acyl chain profile of the adrenal gland lead to the generation of adrenal medullary tumors. Histological analyses revealed that about half of the CerS2 null mice developed PCC by ∼13 months, and the rest showed signs of medullary hyperplasia. Norepinephrine and normetanephrine levels in the urine were elevated at 7 months of age consistent with the morphological abnormalities found at later ages. Accumulation of ceroid in the X-zone was observed as early as 2 months of age and as a consequence, older mice displayed elevated levels of lysosomal cathepsins, reduced proteasome activity and reduced activity of mitochondrial complex IV by 6 months of age. Together, these findings implicate an additional pathway that can lead to PCC formation, which involves alterations in the sphingolipid acyl chain length. Analysis of the role of sphingolipids in PCC may lead to further understanding of the mechanism by which PCC develops, and might implicate the sphingolipid pathway as a possible novel therapeutic target for this rare tumor.
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http://dx.doi.org/10.1530/ERC-15-0058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5586043PMC
August 2015

ERBB2 triggers mammalian heart regeneration by promoting cardiomyocyte dedifferentiation and proliferation.

Nat Cell Biol 2015 May 6;17(5):627-38. Epub 2015 Apr 6.

Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel.

The murine neonatal heart can regenerate after injury through cardiomyocyte (CM) proliferation, although this capacity markedly diminishes after the first week of life. Neuregulin-1 (NRG1) administration has been proposed as a strategy to promote cardiac regeneration. Here, using loss- and gain-of-function genetic tools, we explore the role of the NRG1 co-receptor ERBB2 in cardiac regeneration. NRG1-induced CM proliferation diminished one week after birth owing to a reduction in ERBB2 expression. CM-specific Erbb2 knockout revealed that ERBB2 is required for CM proliferation at embryonic/neonatal stages. Induction of a constitutively active ERBB2 (caERBB2) in neonatal, juvenile and adult CMs resulted in cardiomegaly, characterized by extensive CM hypertrophy, dedifferentiation and proliferation, differentially mediated by ERK, AKT and GSK3β/β-catenin signalling pathways. Transient induction of caERBB2 following myocardial infarction triggered CM dedifferentiation and proliferation followed by redifferentiation and regeneration. Thus, ERBB2 is both necessary for CM proliferation and sufficient to reactivate postnatal CM proliferative and regenerative potentials.
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http://dx.doi.org/10.1038/ncb3149DOI Listing
May 2015

Polioencephalomyelopathy in a mixed breed dog resembling Leigh's disease.

Can Vet J 2015 Jan;56(1):59-62

Veterinary Teaching Hospital, Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel (Chai, Milgram, Shamir); Weizmann Institute of Science, PO Box 26, Rehovot 76100, Israel (Brenner).

A 14-month-old mixed-breed dog was presented with acute onset of exercise intolerance that quickly progressed to quadriparesis. Gross and microscopic autopsy findings indicated a type of degenerative polioencephalomyelopathy resembling subacute necrotizing encephalomyelopathy in dogs or Leigh's disease in humans. This syndrome has previously been reported only in purebred dogs.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266058PMC
January 2015

The effect of naturally occurring chronic kidney disease on the micro-structural and mechanical properties of bone.

PLoS One 2014 15;9(10):e110057. Epub 2014 Oct 15.

Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel.

Chronic kidney disease (CKD) is a growing public health concern worldwide, and is associated with marked increase of bone fragility. Previous studies assessing the effect of CKD on bone quality were based on biopsies from human patients or on laboratory animal models. Such studies provide information of limited relevance due to the small size of the samples (biopsies) or the non-physiologic CKD syndrome studied (rodent models with artificially induced CKD). Furthermore, the type, architecture, structure and biology of the bone of rodents are remarkably different from human bones; therefore similar clinicopathologic circumstances may affect their bones differently. We describe the effects of naturally occurring CKD with features resembling human CKD on the skeleton of cats, whose bone biology, structure and composition are remarkably similar to those of humans. We show that CKD causes significant increase of resorption cavity density compared with healthy controls, as well as significantly lower cortical mineral density, cortical cross-sectional area and cortical cross-sectional thickness. Young's modulus, yield stress, and ultimate stress of the cortical bone material were all significantly decreased in the skeleton of CKD cats. Cancellous bone was also affected, having significantly lower trabecular thickness and bone volume over total volume in CKD cats compared with controls. This study shows that naturally occurring CKD has deleterious effects on bone quality and strength. Since many similarities exist between human and feline CKD patients, including the clinicopathologic features of the syndrome and bone microarchitecture and biology, these results contribute to better understanding of bone abnormalities associated with CKD.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110057PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4198205PMC
December 2015

Macrophage-restricted interleukin-10 receptor deficiency, but not IL-10 deficiency, causes severe spontaneous colitis.

Immunity 2014 May 1;40(5):720-33. Epub 2014 May 1.

Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address:

Interleukin-10 (IL-10) is a pleiotropic anti-inflammatory cytokine produced and sensed by most hematopoietic cells. Genome-wide association studies and experimental animal models point at a central role of the IL-10 axis in inflammatory bowel diseases. Here we investigated the importance of intestinal macrophage production of IL-10 and their IL-10 exposure, as well as the existence of an IL-10-based autocrine regulatory loop in the gut. Specifically, we generated mice harboring IL-10 or IL-10 receptor (IL-10Rα) mutations in intestinal lamina propria-resident chemokine receptor CX3CR1-expressing macrophages. We found macrophage-derived IL-10 dispensable for gut homeostasis and maintenance of colonic T regulatory cells. In contrast, loss of IL-10 receptor expression impaired the critical conditioning of these monocyte-derived macrophages and resulted in spontaneous development of severe colitis. Collectively, our results highlight IL-10 as a critical homeostatic macrophage-conditioning agent in the colon and define intestinal CX3CR1(hi) macrophages as a decisive factor that determines gut health or inflammation.
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http://dx.doi.org/10.1016/j.immuni.2014.03.012DOI Listing
May 2014

Transcription factor Runx3 regulates interleukin-15-dependent natural killer cell activation.

Mol Cell Biol 2014 Mar 13;34(6):1158-69. Epub 2014 Jan 13.

Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.

Natural killer cells belong to the family of innate lymphoid cells comprising the frontline defense against infected and transformed cells. Development and activation of natural killer cells is highly dependent on interleukin-15 signaling. However, very little is known about the transcription program driving this process. The transcription factor Runx3 is highly expressed in natural killer cells, but its function in these cells is largely unknown. We show that loss of Runx3 impaired interleukin-15-dependent accumulation of mature natural killer cells in vivo and under culture conditions and pregnant Runx3(-/-) mice completely lack the unique population of interleukin-15-dependent uterine natural killer cells. Combined chromatin immunoprecipitation sequencing and differential gene expression analysis of wild-type versus Runx3-deficient in vivo activated splenic natural killer cells revealed that Runx3 cooperates with ETS and T-box transcription factors to drive the interleukin-15-mediated transcription program during activation of these cells. Runx3 functions as a nuclear regulator during interleukin-15-dependent activation of natural killer cells by regulating the expression of genes involved in proliferation, maturation, and migration. Similar studies with additional transcription factors will allow the construction of a more detailed transcriptional network that controls natural killer cell development and function.
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http://dx.doi.org/10.1128/MCB.01202-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958033PMC
March 2014

Man made disease: clinical manifestations of low phenylalanine levels in an inadequately treated phenylketonuria patient and mouse study.

Mol Genet Metab 2013 12;110 Suppl:S66-70. Epub 2013 Oct 12.

Metabolic Disease Unit, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel-Hashomer, Israel.

Introduction: Phenylalanine (Phe) deficiency and its clinical manifestations have been previously described mostly as sporadic case reports dating back to the 1960's and 1970's. In these reports, low plasma Phe levels were associated with listlessness, eczematous eruptions and failure to gain weight, most often in infants in their first year of life.

Case Report: Herein we describe a 9 month old female patient with known phenylketonuria, who presented with an unusual constellation of symptoms, including severe erythema and desquamation, alopecia, keratomalacia, corneal perforation, failure to thrive and prolonged diarrhea. The diagnostic possibilities of acrodermatitis enteropathica and vitamin deficiencies were ruled out, and further investigation into her medical history led to the conclusion that during the weeks preceding the hospitalization, the patient's diet consisted of the phenylalanine-free medical formula alone, without the addition of a standard infant formula or food as recommended. Subsequently, dietary control of the blood phenylalanine levels brought swift and marked resolution of the dermatological lesions, with renewal of hair growth.

Objective: Following this experience, and due to the relative paucity of data regarding the clinical manifestations of low serum phenylalanine levels in humans and their putative pathogenetic mechanisms, we sought to further investigate the effects of a phenylalanine-free diet in a mouse study.

Materials And Methods: For this purpose, twenty mice were randomly allocated to receive either a phenylalanine-deficient diet (n=10) or a normal diet (n=10). Weight was measured weekly, and laboratory tests were obtained including complete blood count, electrolyte studies, and phenylalanine and tyrosine levels. Finally, necropsies and histopathological examinations of different tissues were performed in selected mice, either early after diet initiation, late after diet initiation or following re-introduction of normal diets. The study was then repeated in additional two groups of mice, for a period of up to thirteen weeks, with a total of 63 mice.

Results: Gross lesions noted on necropsy in the Phe-deficient mice included scruffy coat, tendency toward weight loss, a reduction in thymic mass, and most notably severe gastric dilation, all of which were not seen in the controls. Histologic findings included thymic depletion, hepatocellular vacuolation, and exocrine pancreatic atrophy. No histopathological lesions were evident in the brain, nor were significant lesions in the eyes.

Conclusions: Diagnosis of the iatrogenic condition of phenylalanine deficiency, which manifests in gastrointestinal, dermatological and ocular findings, requires a high index of suspicion. Mice fed a phenylalanine-deficient diet display to some extent similar organ involvement, although no eye abnormalities were evident.
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http://dx.doi.org/10.1016/j.ymgme.2013.10.006DOI Listing
July 2014

Spontaneous intradural disc herniation with focal distension of the subarachnoid space in a dog.

Can Vet J 2012 Nov;53(11):1191-4

Department of Neurology & Neurosurgery, Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Israel.

Myelo-computed tomography of a paraparetic 14-year-old dog revealed subarachnoid distension with an intradural filling defect above the T13-L1 disc space. T12-L1 hemilaminectomy followed by durotomy allowed removal of a large piece of degenerated disc material that compressed the spinal parenchyma. Full return to function was achieved 10 days post-surgery. The distension was likely secondary to the intradural herniation, and is a rare and distinct finding.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3474575PMC
November 2012

Intrathoracic pseudocyst in a kitten.

J Feline Med Surg 2013 Apr 22;15(4):345-8. Epub 2012 Oct 22.

Veterinary Teaching Hospital Koret School of Veterinary Medicine, The Hebrew University-Small Animal Surgery, Rehovot, Israel.

A 2-month-old, intact, female domestic shorthair kitten presented with a history of acute-onset dyspnoea. Severe dyspnoea and tachypnoea were noted on physical examination. Serosanguinous fluid, consistent with a modified transudate, was aspirated from the pleural cavity immediately after the physical examination, with an immediate decrease in respiratory rate and effort. The thorax was radiographed and the entire left hemithorax appeared to be filled with a large soft tissue density mass. Thoracic ultrasound was performed and a cystic structure, measuring 3.0 cm × 1.5 cm, was seen in the left hemithorax. An explorative thoracotomy was performed and a mass obliterating the left hemithorax was found. The mass was removed by a combination of blunt and sharp dissection. A final diagnosis of thoracic pseudocyst was made on histological examination of the tissue. The mass was described as a sterile process characteristic of an organised seroma or haematoma. Recovery from surgery was uneventful and the kitten was discharged 48 h postoperatively. The kitten was still alive with no recurrence of clinical signs at the time of writing this report, 8 months postoperatively.
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http://dx.doi.org/10.1177/1098612X12464629DOI Listing
April 2013

Nuclear survivin expression as a potentially useful tool for the diagnosis of canine cutaneous sebaceous lesions.

Vet Dermatol 2012 Oct 11;23(5):394-e73. Epub 2012 Jun 11.

Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.

Background: Sebaceous glands are specialized cutaneous adnexal glands, which work under constant hormonal control to produce sebum. They can give rise to several proliferative lesions, such as hamartoma, hyperplasia and neoplasms (adenoma, epithelioma and carcinoma). Their nomenclature is currently confusing, both in veterinary and in human medicine, owing to the difficulty of differentiating between some of these lesions.

Methods: The present study used immunohistochemistry to determine the expression levels and patterns of survivin and Ki67 in five samples of normal canine skin and 44 cases of canine cutaneous lesions with sebaceous differentiation (10 hamartomas, nine hyperplasia, eight adenomas, eight epitheliomas and nine carcinomas).

Results: In normal glands, survivin, as well as Ki67, was expressed in scattered reserve cells. In hamartomas, survivin was more highly expressed than in normal skin, indicating a possible role of this molecule in the pathogenesis of these congenital lesions. In tumours, a moderate or high level of survivin and Ki67 expression (more than two and four and more than two positive cells, respectively) were significantly correlated with a malignant histotype, infiltrative growth and a moderate or high number of mitoses (more than two).

Conclusions And Clinical Importance: The level of survivin expression increased with increasing malignancy, designating survivin as a new diagnostic marker in the assessment of malignancy of sebaceous tumours.
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http://dx.doi.org/10.1111/j.1365-3164.2012.01065.xDOI Listing
October 2012

The ATM-BID pathway regulates quiescence and survival of haematopoietic stem cells.

Nat Cell Biol 2012 Mar 25;14(5):535-41. Epub 2012 Mar 25.

Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel.

BID, a BH3-only BCL2 family member, functions in apoptosis as well as the DNA-damage response. Our previous data demonstrated that BID is an ATM effector acting to induce cell-cycle arrest and inhibition of apoptosis following DNA damage. Here we show that ATM-mediated BID phosphorylation plays an unexpected role in maintaining the quiescence of haematopoietic stem cells (HSCs). Loss of BID phosphorylation leads to escape from quiescence of HSCs, resulting in exhaustion of the HSC pool and a marked reduction of HSC repopulating potential in vivo. We also demonstrate that BID phosphorylation plays a role in protecting HSCs from irradiation, and that regulating both quiescence and survival of HSCs depends on BID's ability to regulate oxidative stress. Moreover, loss of BID phosphorylation, ATM knockout or exposing mice to irradiation leads to an increase in mitochondrial BID, which correlates with an increase in mitochondrial oxidative stress. These results show that the ATM-BID pathway serves as a critical checkpoint for coupling HSC homeostasis and the DNA-damage stress response to enable long-term regenerative capacity.
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http://dx.doi.org/10.1038/ncb2468DOI Listing
March 2012

Antibodies targeting the catalytic zinc complex of activated matrix metalloproteinases show therapeutic potential.

Nat Med 2011 Dec 25;18(1):143-7. Epub 2011 Dec 25.

Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.

Endogenous tissue inhibitors of metalloproteinases (TIMPs) have key roles in regulating physiological and pathological cellular processes. Imitating the inhibitory molecular mechanisms of TIMPs while increasing selectivity has been a challenging but desired approach for antibody-based therapy. TIMPs use hybrid protein-protein interactions to form an energetic bond with the catalytic metal ion, as well as with enzyme surface residues. We used an innovative immunization strategy that exploits aspects of molecular mimicry to produce inhibitory antibodies that show TIMP-like binding mechanisms toward the activated forms of gelatinases (matrix metalloproteinases 2 and 9). Specifically, we immunized mice with a synthetic molecule that mimics the conserved structure of the metalloenzyme catalytic zinc-histidine complex residing within the enzyme active site. This immunization procedure yielded selective function-blocking monoclonal antibodies directed against the catalytic zinc-protein complex and enzyme surface conformational epitopes of endogenous gelatinases. The therapeutic potential of these antibodies has been demonstrated with relevant mouse models of inflammatory bowel disease. Here we propose a general experimental strategy for generating inhibitory antibodies that effectively target the in vivo activity of dysregulated metalloproteinases by mimicking the mechanism employed by TIMPs.
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http://dx.doi.org/10.1038/nm.2582DOI Listing
December 2011

Absence of Runx3 expression in normal gastrointestinal epithelium calls into question its tumour suppressor function.

EMBO Mol Med 2011 Oct 8;3(10):593-604. Epub 2011 Aug 8.

Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel.

The Runx3 transcription factor regulates cell fate decisions during embryonic development and in adults. It was previously reported that Runx3 is strongly expressed in embryonic and adult gastrointestinal tract (GIT) epithelium (Ep) and that its loss causes gastric cancer. More than 280 publications have based their research on these findings and concluded that Runx3 is indeed a tumour suppressor (TS). In stark contrast, using various measures, we found that Runx3 expression is undetectable in GIT Ep. Employing a variety of biochemical and genetic techniques, including analysis of Runx3-GFP and R26LacZ/Runx3(Cre) or R26tdTomato/Runx3(Cre) reporter strains, we readily detected Runx3 in GIT-embedded leukocytes, dorsal root ganglia, skeletal elements and hair follicles. However, none of these approaches revealed detectable Runx3 levels in GIT Ep. Moreover, our analysis of the original Runx3(LacZ/LacZ) mice used in the previously reported study failed to reproduce the GIT expression of Runx3. The lack of evidence for Runx3 expression in normal GIT Ep creates a serious challenge to the published data and undermines the notion that Runx3 is a TS involved in cancer pathogenesis.
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http://dx.doi.org/10.1002/emmm.201100168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258485PMC
October 2011

Encephalopathy caused by ablation of very long acyl chain ceramide synthesis may be largely due to reduced galactosylceramide levels.

J Biol Chem 2011 Aug 24;286(34):30022-33. Epub 2011 Jun 24.

Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.

Sphingolipids (SLs) act as signaling molecules and as structural components in both neuronal cells and myelin. We now characterize the biochemical, histological, and behavioral abnormalities in the brain of a mouse lacking very long acyl (C22-C24) chain SLs. This mouse, which is defective in the ability to synthesize C22-C24-SLs due to ablation of ceramide synthase 2, has reduced levels of galactosylceramide (GalCer), a major component of myelin, and in particular reduced levels of non-hydroxy-C22-C24-GalCer and 2-hydroxy-C22-C24- GalCer. Noteworthy brain lesions develop with a time course consistent with a vital role for C22-C24-GalCer in myelin stability. Myelin degeneration and detachment was observed as was abnormal motor behavior originating from a subcortical region. Additional abnormalities included bilateral and symmetrical vacuolization and gliosis in specific brain areas, which corresponded to some extent to the pattern of ceramide synthase 2 expression, with astrogliosis considerably more pronounced than microglial activation. Unexpectedly, unidentified storage materials were detected in lysosomes of astrocytes, reminiscent of the accumulation that occurs in lysosomal storage disorders. Together, our data demonstrate a key role in the brain for SLs containing very long acyl chains and in particular GalCer with a reduction in their levels leading to distinctive morphological abnormalities in defined brain regions.
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http://dx.doi.org/10.1074/jbc.M111.261206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3191043PMC
August 2011

Beneficial effect of glatiramer acetate treatment on syndecan-1 expression in dextran sodium sulfate colitis.

J Pharmacol Exp Ther 2011 May 10;337(2):391-9. Epub 2011 Feb 10.

Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel.

Syndecan-1, the most abundant heparan sulfate proteoglycan in the gastrointestinal tract, is reduced in the regenerative epithelium in inflammatory bowel disease (IBD). This study explored the effects of the immunomodulator glatiramer acetate (GA; Copaxone) treatment on syndecan-1 expression in dextran sodium sulfate (DSS)-induced colitis. Acute and chronic colitis was induced in C57BL/6 mice by 2 and 1.5% DSS in tap water, respectively. GA was applied subcutaneously, 2 mg per mouse per day, starting on the day of DSS induction until the mice were sacrificed. Syndecan-1 expression was assessed by immunohistochemistry. The effect of adoptive transfer of GA-specific T cells as an organ-specific therapy also was evaluated. Syndecan-1 expression was significantly lower in both colitis groups compared with that in naive mice (p < 0.0001). GA attenuated clinical scores and pathological manifestations of colitis and led to the reinstatement of normal levels of syndecan-1. After adoptive transfer, GA-specific cells homed to the surface epithelium of the distal colon, accompanied by the augmentation of syndecan-1 staining in their vicinity. We concluded that syndecan-1 expression is reduced in DSS-induced colitis and could be a potential prognostic factor in IBD. Treatment with GA exerts not only an anti-inflammatory effect but also a possible beneficial effect in stabilizing the intestinal epithelium barrier and tissue repair in DSS colitis. GA may be applied as a novel drug for IBD, shifting treatment from immunosuppression toward immunomodulation.
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http://dx.doi.org/10.1124/jpet.110.174276DOI Listing
May 2011
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