Characterization of a novel mouse model with genetic deletion of CD177.
Ontology highlight
ABSTRACT:
SUBMITTER: Xie Q
PROVIDER: S-EPMC4312768 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:CD177 plays an important role in the proliferation and differentiation of myeloid lineage cells including neutrophils, myelocytes, promyelocytes, megakaryocytes, and early erythroblasts in bone marrow. CD177 deficiency is a common phenotype in humans. Our previous studies revealed genetic mechanisms of human CD177 deficiency and expression variations. Up to now, immune functions of CD177 remain undefined. In the current study, we revealed human IgG as a ligand for CD177 by using flow cytometry, bead-rosette formation, and surface plasmon resonance (SPR) assays. In addition, we show that CD177 variants affect the binding capacity of CD177 for human IgG. Furthermore, we show that the CD177 genetic variants significantly affect antibody-dependent cell-mediated cytotoxicity (ADCC) function. The demonstration of CD177 as a functional IgG Fc-receptor may provide new insights into CD177 immune function and genetic mechanism underlying CD177 as biomarkers for human diseases.
| S-EPMC11316256 | biostudies-literature
Project description:BackgroundThe Huntingtin (HTT) N-terminal domains encoded by Huntingtin's (HTT) exon 1 consist of an N17 domain, the polyglutamine (polyQ) stretch and a proline-rich region (PRR). These domains are conserved in mammals and have been hypothesized to modulate HTT's functions in the developing and adult CNS, including DNA damage repair and autophagy.ObjectiveThis study longitudinally characterizes the in vivo consequences of deleting the murine Htt N-terminal domains encoded by Htt exon 1.MethodsKnock-in mice with a deletion of Htt exon 1 sequences (HttΔE1) were generated and bred into the C57BL/6J congenic genetic background. Their behavior, DNA damage response, basal autophagy, and glutamatergic synapse numbers were evaluated.ResultsProgeny from HttΔE1/+ intercrosses are born at the expected Mendelian frequency but with a distorted male to female ratio in both the HttΔE1/ΔE1 and Htt+/+ offspring. HttΔE1/ΔE1 adults exhibit a modest deficit in accelerating rotarod performance, and an earlier increase in cortical and striatal DNA damage with elevated neuronal pan-nuclear 53bp1 levels compared to Htt+/+ mice. However, a normal response to induced DNA damage, normal levels of basal autophagy markers, and no significant differences in corticocortical, corticostriatal, thalamocortical, or thalamostriatal synapses numbers were observed compared to controls.ConclusionOur results suggest that deletion of the Htt N-terminus encoded by the Htt exon 1 does not affect Htt's critical role during embryogenesis, but instead, may have a modest effect on certain motor tasks, basal levels of DNA damage in the brain, and Htt function in the testis.
| S-EPMC8595774 | biostudies-literature
Project description:Angelman syndrome (AS) is a neurodevelopmental disorder caused by deficits in maternally inherited UBE3A. The disease is characterized by intellectual disability, impaired motor skills, and behavioral deficits, including increased anxiety and autism spectrum disorder features. The mouse models used so far in AS research recapitulate most of the cardinal AS characteristics. However, they do not mimic the situation found in the majority of AS patients who have a large deletion spanning 4-6 Mb. There is also a large variability in phenotypes reported in the available models, which altogether limits development of therapeutics. Therefore, we have generated a mouse model in which the Ube3a gene is deleted entirely from the 5' UTR to the 3' UTR of mouse Ube3a isoform 2, resulting in a deletion of 76 kb. To investigate its phenotypic suitability as a model for AS, we employed a battery of behavioral tests directed to reveal AS pathology and to find out whether this model better mirrors AS development compared to other available models. We found that the maternally inherited Ube3a-deficient line exhibits robust motor dysfunction, as seen in the rotarod and DigiGait tests, and displays abnormalities in additional behavioral paradigms, including reduced nest building and hypoactivity, although no apparent cognitive phenotype was observed in the Barnes maze and novel object recognition tests. The AS mice did, however, underperform in more complex cognition tasks, such as place reversal in the IntelliCage system, and exhibited a different circadian rhythm activity pattern. We show that the novel UBE3A-deficient model, based on a whole-gene deletion, is suitable for AS research, as it recapitulates important phenotypes characteristic of AS. This new mouse model provides complementary possibilities to study the Ube3a gene and its function in health and disease as well as possible therapeutic interventions to restore function.
| S-EPMC9496699 | biostudies-literature
Project description:Neutrophils are the most abundant white blood cells, with a vital role in innate immune defense against bacterial and fungal pathogens. Although mostly associated with pathological processes directly related to immune defense, they can also play a detrimental role in inflammatory conditions and have been found to have a pro-metastatic role in the spread of cancer cells. Here, we explore ways to temporarily suppress these detrimental activities. We first examined the possibility of using siRNA and antisense oligonucleotides (ASOs) for transient knockdown of the human and mouse C5a receptor, an important chemoattractant receptor involved in neutrophil-mediated injury that is associated with myocardial infarction, sepsis, and neurodegenerative diseases. We found that siRNAs and ASOs transfected into cultured cell lines can eliminate 70-90% of C5a receptor mRNA and protein within 72 h of administration, a clinically relevant time frame after a cardiovascular event. Targeted drug delivery to specific cells or tissues of interest in a mammalian host, however, remains a major challenge. Here, using phage display technology, we have identified peptides that bind specifically to CD177, a neutrophil-specific surface molecule. We have attached these peptides to fluorescent, lipid-based nanoparticles and confirmed targeting and delivery to cultured cells ectopically presenting either human or mouse CD177. In addition, we have shown peptide-nanoparticle binding specifically to neutrophils in human and mouse blood. We anticipate that these or related tagged nanoparticles may be therapeutically useful for delivery of siRNAs or ASOs to neutrophils for transient knockdown of pro-inflammatory proteins such as the C5a receptor.
| S-EPMC6039027 | biostudies-literature
Project description:CYP2A13, CYP2B6, and CYP2F1 are neighboring cytochrome P450 genes on human chromosome 19, and the enzymes that they encode overlap in substrate specificity. A CYP2A13/2B6/2F1-transgenic mouse, in which CYP2A13 and 2F1 are both expressed in the respiratory tract and CYP2B6 is expressed in the liver, was recently generated. We generated a CYP2A13 (only) transgenic mouse so that the specific activity of CYP2A13 can be determined. The CYP2B6 and CYP2F1 genes in the CYP2A13/2B6/2F1 genomic clone were inactivated via genetic manipulations, and CYP2A13 was kept intact. A CYP2A13 (only) transgenic (2A13-TG) mouse was generated using the engineered construct and then characterized to confirm transgene integrity and determine copy numbers. The 2A13-TG mice were normal in gross morphology, development, and fertility. As in the CYP2A13/2B6/2F1-transgenic mouse, CYP2A13 expression in the 2A13-TG mouse was limited to the respiratory tract; in contrast, CYP2B6 and 2F1 proteins were not detected. Additional studies using the CYP2A13-humanized (2A13-TG/Cyp2abfgs-null) mouse produced by intercrossing between 2A13-TG and Cyp2abfgs-null mice confirmed that the transgenic CYP2A13 is active in the bioactivation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a lung procarcinogen. The 2A13-TG mouse should be valuable for assessing specific roles of human CYP2A13 in xenobiotic toxicity in the respiratory tract.
| S-EPMC4109209 | biostudies-literature
Project description:Somatic mutation in the X-linked phosphatidylinositol glycan class A gene (PIG-A) causes glycosyl phosphatidylinositol anchor deficiency in human patients with paroxysmal nocturnal hemoglobinuria.We produced an animal model of paroxysmal nocturnal hemoglobinuria by conditional Pig-a gene inactivation (Pig-a(-/-)) in hematopoietic cells; mice carrying two lox sites flanking exon 6 of the Pig-a gene were bred with mice carrying the transgene Cre-recombinase under the human c-fes promoter. We characterized the phenotypic and functional properties of glycosyl phosphatidylinositol-deficient and glycosyl phosphatidylinositol-normal hematopoietic cells from these Pig-a(-/-) mice using gene expression microarray, flow cytometry, bone marrow transplantation, spectratyping, and immunoblotting.In comparison to glycosyl phosphatidylinositol-normal bone marrow cells, glycosyl phosphatidylinositol-deficient bone marrow cells from the same Pig-a(-/-) animals showed up-regulation of the expression of immune function genes and contained a significantly higher proportion of CD8 T cells. Both characteristics were maintained when glycosyl phosphatidylinositol-deficient cells were transplanted into lethally-irradiated recipients. Glycosyl phosphatidylinositol-deficient T cells were inactive, showed pronounced Vbeta5.1/5.2 skewing, had fewer gamma-interferon-producing cells after lectin stimulation, and contained fewer CD4(+)CD25(+)FoxP3(+) regulatory T cells. However, the levels of T-cell receptor signaling proteins from glycosyl phosphatidylinositol-deficient cells were normal relative to glycosyl phosphatidylinositol-normal cells from wild type animals, and cells were capable of inducing target cell apoptosis in vitro.Deletion of the Pig-a gene in hematopoietic cells does not cause frank marrow failure but leads to the appearance of clonally-restricted, inactive yet functionally competent CD8 T cells.
| S-EPMC2817023 | biostudies-literature
Project description:Aberrant sphingolipid metabolism has been reported to promote breast cancer progression. Sphingosine kinase 1 (SphK1) is a key metabolic enzyme for the formation of pro-survival S1P from pro-apoptotic ceramide. The role of SphK1 in breast cancer has been well studied in estrogen receptor (ER)-positive breast cancer; however, its role in human epidermal growth factor 2 (HER2)-positive breast cancer remains unclear. Here, we show that genetic deletion of SphK1 significantly reduced mammary tumor development with reduced tumor incidence and multiplicity in the MMTV-neu transgenic mouse model. Gene expression analysis revealed significant reduction of claudin-2 (CLDN2) expression in tumors from SphK1 deficient mice, suggesting that CLDN2 may mediate SphK1's function. It is remarkable that SphK1 deficiency in HER2-positive breast cancer model inhibited tumor formation by the different mechanism from ER-positive breast cancer. In vitro experiments demonstrated that overexpression of SphK1 in ER-/PR-/HER2+ human breast cancer cells enhanced cell proliferation, colony formation, migration and invasion. Furthermore, immunostaining of SphK1 and CLDN2 in HER2-positive human breast tumors revealed a correlation in high-grade disease. Taken together, these findings suggest that SphK1 may play a pivotal role in HER2-positive breast carcinogenesis. Targeting SphK1 may represent a novel approach for HER2-positive breast cancer chemoprevention and/or treatment.
| S-EPMC5862258 | biostudies-literature
Project description:The retinoic acid receptor-related receptor α (RORα) is a nuclear receptor that plays an important role in regulation of metabolism and the immune system. Genetic deletion of the receptor yields mice with significant cerebellar developmental issues associated with severe ataxia. Although many metabolic studies have been performed in these models, the impaired locomotor activity of these mice is known to affect their normal mobility and feeding behaviors. This creates some difficulty in interpretation of the role of RORα in models of metabolic disease where feeding and muscle function is a critical component of the pathophysiology. We generated a mouse with a floxed Rora allele that we crossed with a mouse line expressing Cre recombinase under the control of the EIIa promoter to obtain a full body deletion of Rora. This cross led to a partial deletion of the Rora locus likely due to mosaic expression of the EIIa-Cre transgene. These mice lack any signs of ataxia but display an improved metabolic profile relative to normal WT mice. The mice were resistant to diet- and age-induced metabolic syndrome and exhibited improved glucose tolerance and increased insulin sensitivity. Decreased RORα expression in the mice was also associated with reduced inflammation in models of metabolic syndrome. These data indicate that suppression of RORα activity improves metabolic function and reduces inflammation.
| S-EPMC5504173 | biostudies-literature
Project description:The mitochondrial protein SLC25A46 has been recently identified as a novel pathogenic cause in a wide spectrum of neurological diseases, including inherited optic atrophy, Charcot-Marie-Tooth type 2, Leigh syndrome, progressive myoclonic ataxia and lethal congenital pontocerebellar hypoplasia. SLC25A46 is an outer membrane protein, member of the Solute Carrier 25 (SLC25) family of nuclear genes encoding mitochondrial carriers, with a role in mitochondrial dynamics and cristae maintenance. Here we identified a loss-of-function mutation in the Slc25a46 gene that causes lethal neuropathology in mice. Mutant mice manifest the main clinical features identified in patients, including ataxia, optic atrophy and cerebellar hypoplasia, which were completely rescued by expression of the human ortholog. Histopathological analysis revealed previously unseen lesions, most notably disrupted cytoarchitecture in the cerebellum and retina and prominent abnormalities in the neuromuscular junction. A distinct lymphoid phenotype was also evident. Our mutant mice provide a valid model for understanding the mechanistic basis of the complex SLC25A46-mediated pathologies, as well as for screening potential therapeutic interventions.
| S-EPMC5380310 | biostudies-literature
Project description:Proteinase 3 is a serine protease found in neutrophil granules and on the extracellular neutrophil membrane (mPR3). mPR3 is a major antigen for anti-neutrophil cytoplasmic antibodies (PR3-ANCAs), autoantibodies causing fatal autoimmune diseases. In most individuals, a subpopulation of neutrophils also produce CD177, proposed to present additional PR3 on the surface, resulting in CD177neg/mPR3low and CD177pos/mPR3high neutrophil subsets. A positive correlation has been shown between mPR3 abundance, disease incidence, and clinical outcome. We present here a detailed investigation of the PR3:CD177 complex, verifying the interaction, demonstrating the effect of binding on PR3 proteolytic activity and explaining the accessibility of major PR3-ANCA epitopes. We observed high affinity PR3:CD177 complex formation by surface plasmon resonance. Using flow cytometry and a PR3-specific FRET assay, we found that CD177 binding reduced the proteolytic activity of PR3 in vitro using purified proteins, in neutrophil degranulation supernatants containing wtPR3 and directly on mPR3high neutrophils and PR3-loaded HEK cells. Finally, CD177pos/mPR3high neutrophils showed no migration advantage in vitro or in vivo when migrating from the blood into the oral cavity. We illuminate details of the PR3:CD177 interaction explaining mPR3 membrane orientation and proteolytic activity with relevance to ANCA activation of the distinct mPR3 neutrophil populations.
| S-EPMC5327412 | biostudies-literature