The ability to detect early cartilage damage in traumatic injury or degenerative arthritis has been limited, preventing treatment when therapies may be more beneficial. Depletion of proteoglycans/glycoproteins on the surface of the cartilage in these disorders results in unmasking of the underlying type II collagen (CII). This allows CII to serve as an immunologically recognizable target for monoclonal antibody to type II collagen (MabCII). MabCII can be fluorescently labeled for diagnosis of cartilage injury or cartilage degeneration or may be directly coupled to nanosomes encapsulating drugs for localized delivery to the cartilage lesion. Preliminary evidence shows a similar strategy can be used to target and recruit reparative chondrocytes and mesenchymal stem cells to the damaged site. In this application, MabCII will be used in a comprehensive treatment plan for directing reparative cells to lesions of the articular cartilage and meniscal cartilages. The therapeutic efficacy for repairing these cartilages will be monitored by an innovative fluorescent arthroscopy. In addition, we will optimize the recruitment and integration of the reparative cells in the cartilage lesions by reducing MMP production in the joint by intra-articular injection of an inhibitor of activation of the nuclear factor kappa B (NF- KB) pathway encapsulated in MabCII-targeted nanosomes. These procedures are extremely novel and paradigm shifting for the diagnosis and treatment of joint injury and disease.
Our aims are: (1). To diagnose and characterize damaged and degenerative areas of articular surface and meniscal cartilages in the pig knee using a sensitive, MabCII antibody-guided method of fluorescent arthroscopy (FA). The knee of the domestic pig closely resembles a human joint in terms of joint size, weight-bearing requirements, and cartilage thickness and will be used in the characterization of surgically-induced injuries to meniscal and articular cartilages. The damage will be visualized through its binding to fluorescent MabCII using fluorescent arthroscopy, a new procedure that we have developed, and confirmed by histopathology. After FA characterization of the injury, (2) MabCII antibody will be used to target delivery and recruitment of reparative cells to the damaged areas of the knee joint cartilages. We will investigate the therapeutic efficacy of fluorescent, MabCII-targeted chondrocytes or mesenchymal stem cells derived from bone marrow and adipose tissues intra-articularly injected into joints where articular or meniscal cartilages have been surgically damaged monitoring the cellular localization and persistence by FA. Cell to cell recruitment at the cartilage lesion in the knee will be facilitated by an innovative system of biotin/avidin ligands on the surface of the reparative cells and multivalent antibody recruitment of cells binding type II collagen. Reparative tissues will be analyzed over time by histopathology and gene expression by RT-PCR. We will (3) further optimize the recruitment and integration of replacement cells in the cartilage lesion by treatment with MabCII targeted nanosomes loaded with an inhibitor of the activation of the NF-?B pathway. The production of matrix metalloproteinases (MMP) is known to be a factor in degradation of cartilage matrices. Diminishing MMP production will be a prototypic target for enhancing reparative efforts. The MabCII-targeted nanosomes encapsulating a selective inhibitor of human IKK-2, an activator of the NF-?B pathway, will be used as a local delivery system to reduce production of MMPs in damaged cartilage lesions prior to treatment with reparative cells. ! ! !

Public Health Relevance

Post-traumatic osteoarthritis (PTOA) can result from a single or repetitive injury and is a major cause of disability in younger individuals and is of major concern for Veterans who are at increased risk from this condition. The ability to treat this disorder is limited, contributing to the development of disability in affected individuals, with joint replacement the only option. Early detection and treatment of cartilage damage could play a major role in slowing or preventing progression to total joint involvement, sparing pain and expense. We have developed an antibody that recognizes an early marker of PTOA, type II collagen, a protein that becomes exposed in damaged cartilage. We will use this antibody and antibody-targeted nanosomes for early diagnosis of cartilage lesions by fluorescent arthroscopy and for localized delivery of drugs that may be effective, slowing or preventing disease progression. Using a surgical model of cartilage damage in pigs, we will also prove that this antibody can be used to target reparative cells to the damaged area of the cartilage to fill in the defect. !

National Institute of Health (NIH)
Veterans Affairs (VA)
Non-HHS Research Projects (I01)
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Immunology A (IMMA)
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Memphis VA Medical Center
United States
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