1
|
Clayton SW, Walk RE, Mpofu L, Easson GW, Tang SY. Analysis of Infiltrating Immune Cells Following Intervertebral Disc Injury Reveals Recruitment of Gamma-Delta ( γδ) T cells in Female Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582950. [PMID: 38464124 PMCID: PMC10925253 DOI: 10.1101/2024.03.01.582950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Inadequate repair of injured intervertebral discs (IVD) leads to degeneration and contributes to low back pain. Infiltrating immune cells into damaged musculoskeletal tissues are critical mediators of repair, yet little is known about their identities, roles, and temporal regulation following IVD injury. By analyzing longitudinal changes in gene expression, tissue morphology, and the dynamics of infiltrating immune cells following injury, we characterize sex-specific differences in immune cell populations and identify the involvement of previously unreported immune cell types, γδ and NKT cells. Cd3+Cd4-Cd8- T cells are the largest infiltrating lymphocyte population with injury, and we identified the presence of γδ T cells in this population in female mice specifically, and NKT cells in males. Injury-mediated IVD degeneration was prevalent in both sexes, but more severe in males. Sex-specific degeneration may be associated with the differential immune response since γδ T cells have potent anti-inflammatory roles and may mediate IVD repair.
Collapse
Affiliation(s)
| | - Remy E. Walk
- Washington University in St. Louis, St. Louis, MO
| | - Laura Mpofu
- Washington University in St. Louis, St. Louis, MO
| | | | | |
Collapse
|
2
|
Koroth J, Chitwood C, Kumar R, Lin WH, Reves BT, Boyce T, Reineke TM, Ellingson AM, Johnson CP, Stone LS, Chaffin KC, Simha NK, Ogle BM, Bradley EW. Identification of a novel, MSC-induced macrophage subtype via single-cell sequencing: implications for intervertebral disc degeneration therapy. Front Cell Dev Biol 2024; 11:1286011. [PMID: 38274272 PMCID: PMC10808728 DOI: 10.3389/fcell.2023.1286011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 12/22/2023] [Indexed: 01/27/2024] Open
Abstract
Intervertebral disc (IVD) degeneration is a common pathological condition associated with low back pain. Recent evidence suggests that mesenchymal signaling cells (MSCs) promote IVD regeneration, but underlying mechanisms remain poorly defined. One postulated mechanism is via modulation of macrophage phenotypes. In this manuscript, we tested the hypothesis that MSCs produce trophic factors that alter macrophage subsets. To this end, we collected conditioned medium from human, bone marrow-derived STRO3+ MSCs. We then cultured human bone marrow-derived macrophages in MSC conditioned medium (CM) and performed single cell RNA-sequencing. Comparative analyses between macrophages cultured in hypoxic and normoxic MSC CM showed large overlap between macrophage subsets; however, we identified a unique hypoxic MSC CM-induced macrophage cluster. To determine if factors from MSC CM simulated effects of the anti-inflammatory cytokine IL-4, we integrated the data from macrophages cultured in hypoxic MSC CM with and without IL-4 addition. Integration of these data sets showed considerable overlap, demonstrating that hypoxic MSC CM simulates the effects of IL-4. Interestingly, macrophages cultured in normoxic MSC CM in the absence of IL-4 did not significantly contribute to the unique cluster within our comparison analyses and showed differential TGF-β signaling; thus, normoxic conditions did not approximate IL-4. In addition, TGF-β neutralization partially limited the effects of MSC CM. In conclusion, our study identified a unique macrophage subset induced by MSCs within hypoxic conditions and supports that MSCs alter macrophage phenotypes through TGF-β-dependent mechanisms.
Collapse
Affiliation(s)
- Jinsha Koroth
- Department of Orthopedic Surgery, Medical School, University of Minnesota, Minneapolis, MN, United States
| | - Casey Chitwood
- Department of Biomedical Engineering, College of Science and Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Ramya Kumar
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, United States
- Department of Chemistry, College of Science and Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Wei-Han Lin
- Department of Biomedical Engineering, College of Science and Engineering, University of Minnesota, Minneapolis, MN, United States
| | | | | | - Theresa M. Reineke
- Department of Chemistry, College of Science and Engineering, University of Minnesota, Minneapolis, MN, United States
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | - Arin M. Ellingson
- Department of Orthopedic Surgery, Medical School, University of Minnesota, Minneapolis, MN, United States
- Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Casey P. Johnson
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - Laura S. Stone
- Department of Anesthesiology, School of Medicine, University of Minnesota, Minneapolis, MN, United States
| | | | | | - Brenda M. Ogle
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, United States
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | - Elizabeth W. Bradley
- Department of Orthopedic Surgery, Medical School, University of Minnesota, Minneapolis, MN, United States
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| |
Collapse
|
3
|
Jin L, Xiao L, Manley BJ, Oh EG, Huang W, Zhang Y, Chi J, Shi W, Kerrigan JR, Sung SSJ, Kuan CY, Li X. CCR2 monocytes as therapeutic targets for acute disc herniation and radiculopathy in mouse models. Osteoarthritis Cartilage 2024; 32:52-65. [PMID: 37802464 PMCID: PMC10873076 DOI: 10.1016/j.joca.2023.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/27/2023] [Accepted: 08/29/2023] [Indexed: 10/10/2023]
Abstract
OBJECTIVE Back pain and radiculopathy caused by disc herniation are major health issues worldwide. While macrophages are key players in disc herniation induced inflammation, their roles and origins in disease progression remain unclear. We aim to study the roles of monocytes and derivatives in a mouse model of disc herniation. METHODS Using a CCR2-CreER; R26R-EGFP (Ai6) transgenic mouse strain, we fate-mapped C-C chemokine receptor type 2 (CCR2) expressing monocytes and derivatives at disc herniation sites, and employed a CCR2RFP/RFP mouse strain and a CCR2-specific antagonist to study the effects of CCR2+ monocytes on local inflammatory responses, pain level, and disc degeneration by immunostaining, flow cytometry, and histology. RESULTS CCR2+ monocytes (GFP+) increased at the sites of disc hernia over postoperative day 4, 6, and 9 in CCR2-CreER; Ai6 mice. F4/80+ cells increased, and meanwhile, CD11b+ cells trended downward. Co-localization analysis revealed that both GFP+CD11b+ and GFP+F4/80+ constituted the majority of CD11b+ and F4/80+ cells at disc hernia sites. Fluorescence activated cell sorter purified GFP+ cells exhibited higher cytokine expressions than GFP- cells. Inhibition of CCR2 signaling reduced infiltration of monocytes and macrophages, alleviated pain, maintained disc height, and reduced osteoclast activity in adjacent cortical bone for up to 1 month. CONCLUSION Our findings suggest that circulating CCR2+ monocytes play important roles in initiating and promoting the local inflammatory responses, pain sensitization, and degenerative changes after disc herniation, and thus may serve as therapeutic targets for disc herniation induced back and leg pain.
Collapse
Affiliation(s)
- Li Jin
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Li Xiao
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Brock J Manley
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Eunha G Oh
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Wendy Huang
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Yi Zhang
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Jialun Chi
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Weibin Shi
- Department of Radiology and Medical Imaging, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, Charlottesville, VA 22908, USA
| | - Jason R Kerrigan
- Department of Mechanical and Aerospace Engineering, Center of Applied Biomechanics, University of Virginia, Charlottesville, VA 22904, USA
| | - Sun-Sang J Sung
- Department of Medicine, Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Chia-Yi Kuan
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA 22908, USA
| | - Xudong Li
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22904, USA.
| |
Collapse
|