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McIntosh B, Knutsen R, Levin M, Fu YP, Springer D, Kronquist E, Pai C, Heuckeroth R, Kozel B. Baz1b Dosage Influences Cardiovascular Function, Predisposing to Dilated Cardiomyopathy. FASEB J 2022; 36 Suppl 1. [PMID: 35723872 DOI: 10.1096/fasebj.2022.36.s1.r2293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BAZ1B is one of several genes deleted in Williams-Beuren Syndrome (WBS), a complex, multisystem genetic condition that occurs in ~1 in 8000 live births. Also known as Williams Syndrome Transcription Factor (WSTF), BAZ1B is thought to be essential for neural crest migration. To evaluate the impact of Baz1b loss of function, we evaluated the "knockout first" allele of Baz1btm2a(KOMP)Wtsi . Quantitative PCR revealed markedly reduced, but not absent, expression of Baz1b, suggesting that Baz1btm2a(KOMP)Wtsi mutants are knockdowns rather than knockouts. Homozygous Baz1btm2a(KOMP)Wtsi mutant mice die just hours after birth, and both homozygous mutants and heterozygotes are smaller than age-matched wildtype littermates. Survival analyses conducted on 388 Baz1btm2a(KOMP)Wtsi mice revealed that heterozygotes and homozygous mutants are approximately three and sixteen times more likely to die than wildtype mice, respectively [hazard ratio for death in Baz1b+/- : 3.04 (95% CI, 1.83-5.06), p<0.0001; hazard ratio for death in Baz1b-/- : 15.83 (95% CI, 8.54-29.37); p<0.0001]. Furthermore, a linear mixed effects model for the weights of wildtype and heterozygous mice over a 29-day period showed a significant difference in size based on genotype (mean: WT 7.97 g, Baz1b+/- 6.56 g, p<0.0001). Because neural crest lineages contribute to cardiac development, structure, and function, we hypothesized that early sudden death and failure to thrive in mutant mice may be at least partially attributable to cardiac abnormalities. To evaluate any morphologic and functional abnormalities, we performed microCT and echocardiography. MicroCT analysis of the hearts from P0 pups did not reveal congenital heart disease typical of neural crest defects (e.g. tetralogy of Fallot, truncus arteriosus, double outlet right ventricle, or interrupted aortic arch). Echocardiograms, performed at 1-month to align with the growth analysis timeline, revealed mildly decreased ejection fraction (EF, median: WT 64%, Baz1b+/- 56%, p<0.01) and fractional shortening (FS, median: WT 34%, Baz1b+/- 29%, p<0.01), increased left ventricular internal dimension at diastole (LViDd) normalized to animal size (median: WT 0.22 mm/g, Baz1b+/- 0.27 mm/g, p<0.05), and unchanged left ventricular posterior wall dimension at diastole (LVPWd) normalized to body size (median: WT 0.041 mm/g, Baz1b+/- 0.048 mm/g, p=0.19) in Baz1b+/- when compared to wildtype. However, Baz1b+/- LVPWd is significantly smaller than WT when body size is not considered (median: WT 0.63 mm, Baz1b+/- 0.62 mm, p<0.01), suggesting a relationship between cardiac function and mutant animal growth (all tests for genotype in n=14 WT and n=14 Baz1b+/- by Mann-Whitney U Test). Taken together, our data suggest that Baz1b+/- mice exhibit a dilated cardiomyopathy and that dosage for this gene may contribute to early death, decreased somatic growth, and cardiac abnormalities in Baz1b mutant mice. Additional analyses in older mice and with mutants generated using the conditional Baz1btm2a(KOMP)Wtsi allele will allow us to better explore the mechanisms of both the growth failure and cardiomyopathy phenotypes in this model.
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Affiliation(s)
- Basil McIntosh
- Laboratory of Vascular and Matrix Genetics, National Heart, Lung, and Blood Institute, Bethesda, MD
| | - Russell Knutsen
- Laboratory of Vascular and Matrix Genetics, National Heart, Lung, and Blood Institute, Bethesda, MD
| | - Mark Levin
- Laboratory of Vascular and Matrix Genetics, National Heart, Lung, and Blood Institute, Bethesda, MD
| | - Yi-Ping Fu
- National Heart, Lung, and Blood Institute, Bethesda, MD
| | - Danielle Springer
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, Bethesda, MD
| | - Elise Kronquist
- Laboratory of Vascular and Matrix Genetics, National Heart, Lung, and Blood Institute, Bethesda, MD
| | | | | | - Beth Kozel
- Laboratory of Vascular and Matrix Genetics, National Heart, Lung, and Blood Institute, Bethesda, MD
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Jain S, Naughton CK, Yang M, Strickland A, Vij K, Encinas M, Golden J, Gupta A, Heuckeroth R, Johnson EM, Milbrandt J. Mice expressing a dominant-negative Ret mutation phenocopy human Hirschsprung disease and delineate a direct role of Ret in spermatogenesis. Development 2004; 131:5503-13. [PMID: 15469971 DOI: 10.1242/dev.01421] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The Ret receptor tyrosine kinase mediates physiological signals of glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) and is essential for postnatal survival in mice. It is implicated in a number of human diseases and developmental abnormalities. Here, we describe our analyses of mice expressing a Ret mutant (RetDN) with diminished kinase activity that inhibits wild-type Ret activity, including its activation of AKT. All RetDN/+ mice died by 1 month of age and had distal intestinal aganglionosis reminiscent of Hirschsprung disease (HSCR) in humans. The RetDN/+ proximal small intestine also had severe hypoganglionosis and reduction in nerve fiber density, suggesting a potential mechanism for the continued gastric dysmotility in postsurgical HSCR patients. Unlike Ret-null mice, which have abnormalities in the parasympathetic and sympathetic nervous systems, the RetDN/+ mice only had defects in the parasympathetic nervous system. A small proportion of RetDN/+ mice had renal agenesis, and the remainder had hypoplastic kidneys and developed tubulocystic abnormalities postnatally. Postnatal analyses of the testes revealed a decreased number of germ cells, degenerating seminiferous tubules,maturation arrest and apoptosis, indicating a crucial role for Ret in early spermatogenesis.
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Affiliation(s)
- Sanjay Jain
- Department of Pathology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110, USA
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Abstract
Artemin (ARTN) is a member of the GDNF family of ligands and signals through the Ret/GFRalpha3 receptor complex. Characterization of ARTN- and GFRalpha3-deficient mice revealed similar abnormalities in the migration and axonal projection pattern of the entire sympathetic nervous system. This resulted in abnormal innervation of target tissues and consequent cell death due to deficiencies of target-derived neurotrophic support. ARTN is expressed along blood vessels and in cells nearby to sympathetic axonal projections. In the developing vasculature, ARTN is expressed in smooth muscle cells of the vessels, and it acts as a guidance factor that encourages sympathetic fibers to follow blood vessels as they project toward their final target tissues. The chemoattractive properties of ARTN were confirmed by the demonstration that sympathetic neuroblasts migrate and project axons toward ARTN-soaked beads implanted into mouse embryos.
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MESH Headings
- Animals
- Blood Vessels/embryology
- Blood Vessels/innervation
- Blood Vessels/metabolism
- Cell Death/genetics
- Cell Differentiation/genetics
- Cell Movement/genetics
- Cell Survival/genetics
- Chemotaxis/genetics
- Digestive System/blood supply
- Digestive System/innervation
- Female
- Fetus
- Ganglia, Sympathetic/abnormalities
- Ganglia, Sympathetic/cytology
- Ganglia, Sympathetic/metabolism
- Gene Expression Regulation, Developmental/physiology
- Glial Cell Line-Derived Neurotrophic Factor Receptors
- Horner Syndrome/genetics
- Horner Syndrome/pathology
- Horner Syndrome/physiopathology
- Membrane Glycoproteins
- Mice
- Mice, Knockout
- Muscle, Smooth, Vascular/embryology
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Nerve Growth Factors/deficiency
- Nerve Growth Factors/genetics
- Nerve Growth Factors/metabolism
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/cytology
- Neurons/metabolism
- Neurons, Afferent/cytology
- Neurons, Afferent/metabolism
- Pregnancy
- Receptors, Cell Surface/deficiency
- Receptors, Cell Surface/genetics
- Receptors, Nerve Growth Factor
- Splanchnic Circulation/genetics
- Sympathetic Nervous System/abnormalities
- Sympathetic Nervous System/cytology
- Sympathetic Nervous System/metabolism
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Affiliation(s)
- Yutaka Honma
- Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Seiden MV, Heuckeroth R, Clevinger B, McMillan S, Lerner R, Davie JM. Hypervariable region peptides variably induce specific anti-idiotypic antibodies: an approach to determining antigenic dominance. The Journal of Immunology 1986. [DOI: 10.4049/jimmunol.136.2.582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Rats and rabbits were immunized with synthetic peptides corresponding to the VH hypervariable regions of several alpha (1----3) dextran-specific antibodies from mice to study the efficacy of synthetic peptides in the generation of site-specific anti-idiotypic reagents. Synthetic peptides were made which corresponded to the HV1, HV2, and HV3 hypervariable regions of the heavy chain of M104 (IdX+, IdI-(M104)+), HV2 of HDex 14 (IdX-), and HV3 of J558 (IdX+, IdI(J558)+). The HV1(M104) peptide sequence is found in all dextran-specific immunoglobulins examined and the HV2 and the HV3 peptides span the regions implicated in IdX and IdI expression, respectively. Sera from many rabbits and rats indicate that all five peptides are immunogenic. Antisera to HV3 peptides show excellent binding to the appropriate myeloma proteins, with antisera to the HV3(M104) peptide demonstrating little binding to proteins that differ in HV3 sequence. Antisera generated against HV1(M104) and both HV2 peptides show weak cross-reaction to the appropriate proteins; however, these sera are not idiotypic because they cross-react with immunoglobulins with very limited sequence homology. Thus, it appears that some, but not all synthetic peptides from hypervariable regions will be capable of generating antisera with useful anti-idiotypic specificities. This may reflect differences in the intrinsic antigenicity of various parts of the VH region.
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Seiden MV, Heuckeroth R, Clevinger B, McMillan S, Lerner R, Davie JM. Hypervariable region peptides variably induce specific anti-idiotypic antibodies: an approach to determining antigenic dominance. J Immunol 1986; 136:582-7. [PMID: 2416815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Rats and rabbits were immunized with synthetic peptides corresponding to the VH hypervariable regions of several alpha (1----3) dextran-specific antibodies from mice to study the efficacy of synthetic peptides in the generation of site-specific anti-idiotypic reagents. Synthetic peptides were made which corresponded to the HV1, HV2, and HV3 hypervariable regions of the heavy chain of M104 (IdX+, IdI-(M104)+), HV2 of HDex 14 (IdX-), and HV3 of J558 (IdX+, IdI(J558)+). The HV1(M104) peptide sequence is found in all dextran-specific immunoglobulins examined and the HV2 and the HV3 peptides span the regions implicated in IdX and IdI expression, respectively. Sera from many rabbits and rats indicate that all five peptides are immunogenic. Antisera to HV3 peptides show excellent binding to the appropriate myeloma proteins, with antisera to the HV3(M104) peptide demonstrating little binding to proteins that differ in HV3 sequence. Antisera generated against HV1(M104) and both HV2 peptides show weak cross-reaction to the appropriate proteins; however, these sera are not idiotypic because they cross-react with immunoglobulins with very limited sequence homology. Thus, it appears that some, but not all synthetic peptides from hypervariable regions will be capable of generating antisera with useful anti-idiotypic specificities. This may reflect differences in the intrinsic antigenicity of various parts of the VH region.
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