Mark Horowitz, PhD
Professor Emeritus of Orthopaedics & Rehabilitation, Senior Research ScientistCards
Appointments
Orthopaedics & Rehabilitation
Primary, Secondary
Contact Info
Orthopaedics & Rehabilitation
P.O. Box 208071
New Haven, CT 06520-8071
United States
About
Titles
Professor Emeritus of Orthopaedics & Rehabilitation, Senior Research Scientist
Appointments
Orthopaedics & Rehabilitation
EmeritusPrimaryOrthopaedics & Rehabilitation
Senior Research ScientistSecondary
Other Departments & Organizations
- Diabetes Research Center
- Fellowship Training
- Obesity Research Working Group
- Orthopaedic Histology and Histomorphometry Laboratory
- Orthopaedics & Rehabilitation
- Rheumatic Diseases Research Core
- Yale Ventures
Education & Training
- PhD
- SUNY Upstate Med Center (1977)
- BS
- Syracuse University, Biology/Biology (1972)
- MS
- Yale University
- Fellow
- Yale University School of Medicine
Research
Overview
The laboratory is focused on two areas. The first, is osteoimmunology and the second is the relationship of adipose tissue to bone. To this end we are examining a number of transgenic animal models many of which have specific transcription factors deleted, one result being bone alterations. As an example the loss of GATA-1, a transcription factor required for megakaryocyte differentiation, have a phenotype characterized by an increase in the number of megakaryocytes, no functional platelets and a massive increase in both trabecular and cortical bone. We are in the process of characterizing both the bone phenotype and the underlying mechanism responsible for the increased bone mass. In addition, we are looking at mice deficient in transcription factors required for B cell differentiation. Ebf1 deficient mice lack B cells but also have increased bone formation and increased marrow fat. Increased fat usually occurs at the expense of osteoblastogenesis. Because of the lipodystrophic phenotype of Ebf1 deficient mice, we are developing models for increased marrow fat. Marrow fat increases with age. However, is function as well as its origin are unknown. In a separate project, we are isolating cells from inside, rather than on bone surfaces. These cells are heterogeneous and have some characteristics of osteocytes.
- Analysis of the bone and fat phenotype of mice lacking the B cell transcription factors Ebf1 and Pax5
- Analysis of the bone phenotype of mice lacking GATA1
- Isolation and characterization of bone cells from inside bone (osteocytes).
- Develop mouse models for marrow fat.
Medical Subject Headings (MeSH)
Adipocytes; Bone and Bones; Bone Remodeling; Mesenchymal Stem Cell Transplantation; Orthopedics; Osteoblasts; Osteoclasts
Research at a Glance
Yale Co-Authors
Frequent collaborators of Mark Horowitz's published research.
Research Interests
Research topics Mark Horowitz is interested in exploring.
David G. Schatz, PhD
Jackie A. Fretz, PhD
Osteoblasts
Adipocytes
Publications
2024
Intermittent Methionine Restriction Reduces Marrow Fat Accumulation and Preserves More Bone Mass than Continuous Methionine Restriction
Plummer J, Horowitz M, Johnson J. Intermittent Methionine Restriction Reduces Marrow Fat Accumulation and Preserves More Bone Mass than Continuous Methionine Restriction. Aging Biology 2024, 2: 20230019. PMID: 38550776, PMCID: PMC10977905, DOI: 10.59368/agingbio.20230019.Peer-Reviewed Original ResearchAltmetricConceptsMetabolic health benefitsBone massMethionine restrictionContinuous MRStatic histomorphometric analysisAccumulation of marrow fatMarrow fat accumulationLean body massMethionine-restricted dietLong-term adherenceCortical boneFemale miceMale miceDietary interventionHistomorphometric analysisDeleterious effectsContinuous interventionMarrow fatMiceAge-related pathologiesIntermittent formMammalian healthspanBoneConsistent with such findingsStrength of bone
2008
Ebf1-dependent control of the osteoblast and adipocyte lineages
Hesslein DG, Fretz JA, Xi Y, Nelson T, Zhou S, Lorenzo JA, Schatz DG, Horowitz MC. Ebf1-dependent control of the osteoblast and adipocyte lineages. Bone 2008, 44: 537-546. PMID: 19130908, PMCID: PMC2657874, DOI: 10.1016/j.bone.2008.11.021.Peer-Reviewed Original ResearchCitationsMeSH Keywords and ConceptsConceptsNumber of osteoclastsBone formation parametersBone formation rateAdipocyte lineageBone marrow cellsOlfactory sensory neuronsSerum osteocalcinOsteoid volumeSensory neuronsAdipocyte numberBone marrowOsteoclast developmentMutant miceMarrow cellsMiceSubcutaneous sitesBone formationAdipocyte developmentStriking increaseDecreased depositionTranscription factorsOsteoblastsB cell fate specificationEBF1AdiposityThe role of gap junctions in megakaryocyte-mediated osteoblast proliferation and differentiation
Ciovacco WA, Goldberg CG, Taylor AF, Lemieux JM, Horowitz MC, Donahue HJ, Kacena MA. The role of gap junctions in megakaryocyte-mediated osteoblast proliferation and differentiation. Bone 2008, 44: 80-86. PMID: 18848655, PMCID: PMC2659565, DOI: 10.1016/j.bone.2008.08.117.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsMeSH KeywordsAlkaline PhosphataseAnimalsAnimals, NewbornCalciumCell CommunicationCell DifferentiationCell LineCell ProliferationConnexin 43Extracellular SpaceFemaleFlow CytometryGap JunctionsGene Expression RegulationGlycyrrhetinic AcidHumansMegakaryocytesMiceOleic AcidsOsteoblastsPregnancyReverse Transcriptase Polymerase Chain ReactionTritiumConceptsGJ intercellular communicationGene expressionIntercellular communicationGap junctionsOB proliferationMembrane-spanning channelsAbility of megakaryocytesPhosphatase enzymatic activityAlkaline phosphatase enzymatic activityOsteoblast proliferationBone cellsGJ proteinsPotential novel targetSignaling mechanismMatrix proteinsNodule formationEnzymatic activityEnzymatic levelsNovel targetMegakaryocytesDifferentiationOB culturesProteinConnexin 43Proliferation
Academic Achievements and Community Involvement
activity NIH
Peer Review Groups and Grant Study SectionsMemberDetailsStudy Section member and former Chairmanhonor Co-Director, Yale Core Center for Musculoskeletal Disorders
National AwardNIHDetails07/01/2014, 04/01/1999United Statesactivity School of medicine
CommitteesMemberDetailsSenior Faculty Allotment Committee2005 - 2008
Links & Media
News
- October 15, 2020
Forty Years Amidst the Bones
- September 24, 2019
A breath of fresh air
- December 01, 2008
Grants and contracts awarded to Yale School of Medicine
Get In Touch
Contacts
Academic Office Number
Mailing Address
Orthopaedics & Rehabilitation
P.O. Box 208071
New Haven, CT 06520-8071
United States