Spontaneous mutations in the SHANK-associated RH domain interacting protein (Sharpin) resulted in a severe autoinflammatory type of chronic proliferative dermatitis, inflammation in other organs, and ...lymphoid organ defects. To determine whether cell-type restricted loss of Sharpin causes similar lesions, a conditional null mutant was created. Ubiquitously expressing cre-recombinase recapitulated the phenotype seen in spontaneous mutant mice. Limiting expression to keratinocytes (using a Krt14-cre) induced a chronic eosinophilic dermatitis, but no inflammation in other organs or lymphoid organ defects. The dermatitis was associated with a markedly increased concentration of serum IgE and IL18. Crosses with S100a4-cre resulted in milder skin lesions and moderate to severe arthritis. This conditional null mutant will enable more detailed studies on the role of SHARPIN in regulating NFkB and inflammation, while the Krt14-Sharpin-/- provides a new model to study atopic dermatitis.
The membrane protein ANKH was known to prevent pathological mineralization of joints and was thought to export pyrophosphate (PPi) from cells. This did not explain, however, the presence of ANKH in ...tissues, such as brain, blood vessels and muscle. We now report that in cultured cells ANKH exports ATP, rather than PPi, and, unexpectedly, also citrate as a prominent metabolite. The extracellular ATP is rapidly converted into PPi, explaining the role of ANKH in preventing ankylosis. Mice lacking functional Ank (Ankank/ank mice) had plasma citrate concentrations that were 65% lower than those detected in wild type control animals. Consequently, citrate excretion via the urine was substantially reduced in Ankank/ank mice. Citrate was even undetectable in the urine of a human patient lacking functional ANKH. The hydroxyapatite of Ankank/ank mice contained dramatically reduced levels of both, citrate and PPi and displayed diminished strength. Our results show that ANKH is a critical contributor to extracellular citrate and PPi homeostasis and profoundly affects bone matrix composition and, consequently, bone quality.
Lipids are important structural and functional components of the skin. Alterations in the lipid composition of the epidermis are associated with inflammation and can affect the barrier function of ...the skin. SHARPIN-deficient cpdm mice develop a chronic dermatitis with similarities to atopic dermatitis in humans. Here, we used a recently-developed approach named multiple reaction monitoring (MRM)-profiling and single ion monitoring to rapidly identify discriminative lipid ions. Shorter fatty acyl residues and increased relative amounts of sphingosine ceramides were observed in cpdm epidermis compared to wild type mice. These changes were accompanied by downregulation of the Fasn gene which encodes fatty acid synthase. A profile of diverse lipids was generated by fast screening of over 300 transitions (ion pairs). Tentative attribution of the most significant transitions was confirmed by product ion scan (MS/MS), and the MRM-profiling linear intensity response was validated with a C17-ceramide lipid standard. Relative quantification of sphingosine ceramides CerAS(d18:1/24:0)2OH, CerAS(d18:1/16:0)2OH and CerNS(d18:1/16:0) discriminated between the two groups with 100% accuracy, while the free fatty acids cerotic acid, 16-hydroxy palmitic acid, and docosahexaenoic acid (DHA) had 96.4% of accuracy. Validation by liquid chromatography tandem mass spectrometry (LC-MS/MS) of the above-mentioned ceramides was in agreement with MRM-profiling results. Identification and rapid monitoring of these lipids represent a tool to assess therapeutic outcomes in SHARPIN-deficient mice and other mouse models of dermatitis and may have diagnostic utility in atopic dermatitis.
Role of COL4A1 in Small-Vessel Disease and Hemorrhagic Stroke Gould, Douglas B; Phalan, F. Campbell; van Mil, Saskia E ...
New England journal of medicine/The New England journal of medicine,
04/2006, Letnik:
354, Številka:
14
Journal Article
Recenzirano
Odprti dostop
This study shows that mice with mutant type IV collagen α1 protein are susceptible to trauma-induced hemorrhage and stroke. Building on this finding is the discovery that a variant of the human ...orthologue is associated with small-vessel disease and hemorrhagic stroke.
This study shows that mice with mutant type IV collagen α1 protein are susceptible to trauma-induced hemorrhage and stroke.
Stroke is a leading cause of death and serious long-term disability in developed nations.
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Survivors often have a severely diminished quality of life, require long-term care, and are at high risk for recurrence.
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Intracerebral hemorrhage accounts for 10 to 15 percent of strokes and is a particularly severe form of stroke, with disproportionately high rates of death and long-term disability.
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Hypertension and amyloid angiopathy are important risk factors associated with intracerebral hemorrhage; other risk factors include vascular malformations, coagulation abnormalities, and the use of sympathomimetic drugs.
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However, intracerebral hemorrhage often occurs in the absence of a history of known risk . . .
The International Knockout Mouse Consortium was formed in 2007 to inactivate ("knockout") all protein-coding genes in the mouse genome in embryonic stem cells. Production and characterization of ...these mice, now underway, has generated and phenotyped 3,100 strains with knockout alleles. Skin and adnexa diseases are best defined at the gross clinical level and by histopathology. Representative retired breeders had skin collected from the back, abdomen, eyelids, muzzle, ears, tail, and lower limbs including the nails. To date, 169 novel mutant lines were reviewed and of these, only one was found to have a relatively minor sebaceous gland abnormality associated with follicular dystrophy. The B6N(Cg)-Far2tm2b(KOMP)Wtsi/2J strain, had lesions affecting sebaceous glands with what appeared to be a secondary follicular dystrophy. A second line, B6N(Cg)-Ppp1r9btm1.1(KOMP)Vlcg/J, had follicular dystrophy limited to many but not all mystacial vibrissae in heterozygous but not homozygous mutant mice, suggesting that this was a nonspecific background lesion. We discuss potential reasons for the low frequency of skin and adnexal phenotypes in mice from this project in comparison to those seen in human Mendelian diseases, and suggest alternative approaches to identification of human disease-relevant models.
In contrast to the prominent function of the blood vasculature in promoting tissue inflammation, the role of lymphatic vessels in inflammation has been scarcely studied in vivo. To investigate ...whether modulating lymphatic vessel function might affect the course of chronic inflammation, the major lymphangiogenic receptor, vascular growth factor receptor 3 (VEGFR-3, FLT4), was blocked in an established model of inflammatory bowel disease.
Interleukin 10 (IL10)-deficient mice that spontaneously develop inflammatory bowel disease were treated with a blocking antibody to VEGFR-3 for 18 days, and the inflammatory changes in colon tissue and the blood and lymphatic vascularization were quantitatively analyzed.
We found a significant increase in the severity of colon inflammation in anti-VEGFR-3-treated mice. This was accompanied by an increased number of enlarged and tortuous lymphatic vessels and edema in colon submucosa, indicating impaired lymphatic function. In contrast, no major effects of the treatment on the blood vasculature were observed.
These results indicate that therapies aimed at promoting lymphatic function, e.g., with prolymphangiogenic factors, such as VEGF-C, might provide a novel strategy for the treatment of inflammatory conditions, such as inflammatory bowel disease.
In October 2010, a pathology review of rodent models of intestinal neoplasia was held at The Jackson Laboratory. This review complemented 2 other concurrent events: a workshop on methods of modeling ...colon cancer in rodents and a conference on current issues in murine and human colon cancer. We summarize the results of the pathology review and the committee's recommendations for tumor nomenclature. A virtual high-resolution image slide box of these models has been developed. This report discusses significant recent developments in rodent modeling of intestinal neoplasia, including the role of stem cells in cancer and the creation of models of metastatic intestinal cancer.
Pseudoxanthoma elasticum, a heritable ectopic mineralization disorder, is caused by mutations in the ABCC6 gene primarily expressed in the liver and the kidneys. The fundamental question on ...pathogenesis of pseudoxanthoma elasticum, whether lack of ABCC6 expression in liver or kidney is the primary site of molecular pathology in peripheral tissues, has not been addressed. We generated a series of Abcc6−/− rats as models of pseudoxanthoma elasticum depicting ectopic mineralization in the skin, eyes, and the arterial blood vessels. Plasma inorganic pyrophosphate (PPi) level was reduced (<30%) in the Abcc6−/− rats leading to a lowered PPi/inorganic phosphate plasma ratio. In situ liver and kidney perfusions were performed to determine the relative contribution of these organs to PPi levels in circulation. PPi levels in the perfusates both in the liver and kidney of Abcc6−/− rats were significantly reduced, but the PPi levels in the liver perfusates of wild-type rats were 10-fold higher than that in the kidney perfusates. These observations suggest a critical role of hepatic ABCC6 in contributing to plasma PPi levels, identifying liver as a target of molecular correction to counteract ectopic mineralization in pseudoxanthoma elasticum.
Pseudoxanthoma elasticum (PXE), a prototype of heritable ectopic mineralization disorders, is caused in most cases by inactivating mutations in the ABCC6 gene. It was recently discovered that absence ...of ABCC6-mediated adenosine triphosphate release from the liver and consequently reduced plasma inorganic pyrophosphate (PPi) levels underlie PXE. This study examined whether reduced levels of circulating PPi, an antimineralization factor, is the sole mechanism of PXE. The Abcc6–/– and Enpp1asj mice were crossed with transgenic mice expressing human ENPP1, an ectonucleotidase that generates PPi from adenosine triphosphate. We generated Abcc6–/– and Enpp1asj mice, either wild-type or hemizygous for human ENPP1. Plasma levels of PPi and the degree of ectopic mineralization were determined. Overexpression of human ENPP1 in Enpp1asj mice normalized plasma PPi levels to that of wild-type mice and, consequently, completely prevented ectopic mineralization. These changes were accompanied by restoration of their bone microarchitecture. In contrast, although significantly reduced mineralization was noted in Abcc6–/– mice expressing human ENPP1, small mineralization foci were still evident despite increased plasma PPi levels. These results suggest that PPi is the major mediator of ectopic mineralization in PXE, but there might be an alternative, as yet unknown mechanism, independent of PPi, by which ABCC6 prevents ectopic mineralization under physiologic conditions.
Previous work strongly implicated Collagen 17a1 (Col17a1) as a potent genetic modifier of junctional epidermolysis bullosa (JEB) caused by a hypomorphic mutation (Lamc2jeb) in mice. The importance of ...the noncollagenous domain (NC4) of COLXVII was suggested by use of a congenic reduction approach that restricted the modifier effect to 2-3 neighboring amino acid changes in that domain. The current study utilizes TALEN and CRISPR/Cas9 induced amino acid replacements and in-frame indels nested to NC4 to further investigate the role of this and adjoining COLXVII domains both as modifiers and primary risk effectors. We confirm the importance of COLXVI AA 1275 S/G and 1277 N/S substitutions and utilize small nested indels to show that subtle changes in this microdomain attenuate JEB. We further show that large in-frame indels removing up to 1482 bp and 169 AA of NC6 through NC1 domains are surprisingly disease free on their own but can be very potent modifiers of Lamc2jeb/jeb JEB. Together these studies exploiting gene editing to functionally dissect the Col17a1 modifier demonstrate the importance of epistatic interactions between a primary disease-causing mutation in one gene and innocuous 'healthy' alleles in other genes.
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