자료유형  

 학위논문

Control Number  

0016933711

International Standard Book Number  

9798379566906

Dewey Decimal Classification Number  

610

Main Entry-Personal Name  

Kaur, Gurcharan.

Publication, Distribution, etc. (Imprint  

[S.l.] : University of Michigan., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(141 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

General Note  

Advisor: Coleman, Rhima.

Dissertation Note  

Thesis (Ph.D.)--University of Michigan, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Restrictions on Access Note  

This item must not be added to any third party search indexes.

Summary, Etc.  

요약Articular cartilage has limited healing capability, resulting in cartilage injuries to often progress into post traumatic osteoarthritis (PTOA), a painful debilitating disease. Adult human mesenchymal stem cell (hMSC)-based tissue engineering strategies have been widely explored to achieve functional cartilage repair due to their ability to differentiate into chondrocytes and secrete cartilage matrix macromolecules collagen II and aggrecan. However, clinical application of MSC-based cartilage repair strategies faces two significant challenges. First, upon chondrogenic differentiation, MSC-derived chondrocytes (hMdChs) undergo hypertrophic maturation driven by master transcription factor RUNX2. Second, the inflammatory environment of the injured joint, established predominantly by pro-inflammatory macrophages, accelerates chondrocyte hypertrophy and matrix degradation, a process also mediated by RUNX2 activity. Inflammatory cytokines induce hMdChs to secrete further inflammatory and catabolic factors, establishing a positive feed forward loop that sustains the joint inflammation. This results in matrix loss which compromises the functionality of engineered cartilage. The central objective of this thesis is to increase matrix accumulation and retention by hMdChs under hypertrophic and inflammatory conditions to improve cartilage regeneration. We hypothesize RUNX2 suppression can increase matrix accumulation by 1) maintaining the production of cartilage structural proteins, 2) protecting the cells from hypertrophy and inflammation induced matrix degradation by inhibiting matrix metalloproteinase (MMP) expression and, 3) inhibiting the pro-inflammatory crosstalk between hMdChs and M1 macrophages. To evaluate these hypotheses, we used a synthetic gene circuit that induces autonomous and tunable RUNX2 suppression in hMdChs based on intracellular RUNX2 concentrations. In Aim 1, I show that suppressing RUNX2 activity using our gene circuit increases matrix accumulation and inhibits matrix mineralization under hypertrophic conditions. Moreover, RUNX2 suppression stabilizes the expression of chondrogenic markers collagen II and aggrecan and inhibits the expression of hypertrophic markers MMP13 and collagen X in hMdChs under hypertrophic stimulus. These results indicate that the gene circuit increases the stability of hMdCh chondrogenic phenotype. In Aim 2, I show that RUNX2 suppression protects hMdChs from inflammatory cytokine IL-1β induced cartilage matrix catabolism. Moreover, I show that under inflammatory stimulus, RUNX2 suppression in hMdChs increases matrix retention by preserving the expression of cartilage matrix macromolecules and inhibiting the expression of hypertrophic and catabolic markers. In Aim 3, using a conditioned media-based co-culture model to recapitulate the injured joint environment, I show that RUNX2 suppression protects hMdChs from M1 conditioned media (M1CM) induced matrix catabolism partly by inhibiting MMP13 expression. Moreover, RUNX2 suppression abates the pro-inflammatory response of hMdChs to M1CM. Finally, pro-inflammatory M1 macrophages treated with the secretome of RUNX2 suppressing hMdChs exhibited downregulation of inflammatory markers and upregulation of anti-inflammatory markers indicating a shift towards anti-inflammatory phenotype. This thesis reveals that RUNX2 mediates many pathological features of PTOA progression. Although the role of RUNX2 in mediating hypertrophy and cartilage matrix catabolism is well known, I demonstrate the application of autoregulated gene circuits to study the RUNX2 mediated pro-inflammatory crosstalk between hMdChs and pro-inflammatory macrophages that reinforces macrophage inflammation, resulting PTOA progression. As demonstrated in this dissertation, the ability to concomitantly improve cartilage matrix accumulation and resolve joint inflammation utilizing autoregulated gene circuits, is a significant step towards clinical application of MSC-based tissue engineering strategies for cartilage regeneration.

Subject Added Entry-Topical Term  

Biomedical engineering.

Subject Added Entry-Topical Term  

Molecular biology.

Index Term-Uncontrolled  

Cartilage

Index Term-Uncontrolled  

Mesenchymal stem cells

Index Term-Uncontrolled  

Tissue engineering

Index Term-Uncontrolled  

Post-traumatic osteoarthritis

Added Entry-Corporate Name  

University of Michigan Biomedical Engineering

Host Item Entry  

Dissertations Abstracts International. 84-12B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

로그인을 한후 보실 수 있는 자료입니다.

Control Number  

joongbu:643724