CD226 Is Required to Maintain Megakaryocytes/Platelets Homeostasis in the Treatment of Knee Osteoarthritis With Platelet-Rich Plasma in Mice

Abstract

Platelet-rich plasma (PRP) is a platelet-based application used to treat osteoarthritis (OA) clinically. The co-stimulatory molecule CD226 is expressed in T cells, NK cells, and also platelets. However, exact effects of CD226 on platelets and whether its expression level influences PRP efficacy are largely unknown. Here, CD226fl/flPF4-Cre mice were obtained from mating CD226 fl/fl mice with PF4-Cre mice. Blood samples and washed platelets were collected from the mice eyeballs to undergo routine blood tests and transmission electron microscopy. Differentially expressed proteins were detected by iTRAQ-based proteomics analysis. Animal OA models were established through surgical destabilization of the medial meniscus (DMM) for C57BL/6 wildtype mice, followed by PRP injection to evaluate the effects of platelet CD226 on PRP efficacy. The results showed that deletion of platelet CD226 increased the number of megakaryocytes (MKs) in bone marrow (BM) but reduced MKs in spleen, combined with significantly decreased platelet amounts, α-granule secretion, and reduced immature platelets; indicating that absence of platelet CD226 may disrupt MK/platelet homeostasis and arrested platelet release from MKs. Sequencing analysis showed abnormal ribosomal functions and much downregulated proteins in the absence of platelet CD226. Autophagy-related proteins were also reduced in the CD226-absent MKs/platelets. Moreover, deletion of platelet CD226 diminished the protective effects of PRP on DMM-induced cartilage lesions in mice, and PDGF restored it. Therefore, deficiency of platelet CD226 inhibited platelet maturation, secretion, and normal ribosomal functions, which may lead to depressed PRP efficacy on OA, suggesting that CD226 is required to regulate platelet growth, functions, and its application.

"Hematopoietic Elements in Osteoarthritic Femurs Compared to Normal Bone Marrow as Evaluated by Immunohistochemistry"

“…Breakdown of cartilage and subchondral bone may allow for exchange of larger-than-normal molecules to influence signaling pathways and increase cross-talk between the normally unconnected compartments of synovium and bone marrow [19]. Studies have shown cellular fractions such as macrophages, osteoblasts, osteocytes, adipocytes, T-cells, B-cells, megakaryocytes, granulocytes, and osteoblasts found in the bone/bone marrow may affect, or be affected by, the cartilage and subchondral bone changes seen in OA joints [10][11][12][13][14][15][16][17][18].…”

“…The degenerative changes which include thinning of cartilage layers, increase in subchondral bone content, increased underlying bone remodeling, and fissures which penetrate both cartilage and bone have been well documented [2][3][4][5][6][7][8][9]. Qualitative and quantitative studies have evaluated adipocyte, T-cell, B-cell, macrophage, megakaryocyte, granulocyte, osteoblast, osteoclast, and osteocyte activity that affects the cartilage and subchondral bone in OA [10][11][12][13][14][15][16][17][18]. The goal of the study was to evaluate the hematopoietic elements in the proximal end of the osteoarthritic femur head as they compare to hematopoietic elements in normal bone marrow aspirates collected from the traditional posterior iliac crest to determine whether the joint pressure and bone degeneration influences the underlying blood cell fractions.…”

High‐fat diet aggravates the severity of the in vitro posttraumatic osteoarthritis model through macrophagic FBW7

“…Synovial fluid from the joints was collected by thorough washing with PBS, and macrophages were isolated. The Osteoarthritis Research Society International (OARSI) scoring system was employed to evaluate the severity of OA in the medial femoral condyle and medial tibial plateau, as previously described 16,17 . Briefly, the OARSI scoring system involves the analysis of articular cartilage in two representative sections from each stained slide to assess the pathological condition of each joint.…”

“…In this study, we employed the destabilization of the medial meniscus (DMM) surgical procedure to establish the OA model, as described in previous studies. 15 , 16 , 17 The right knee of mice underwent DMM surgery to induce OA, while the left knees were sham‐operated. A xylazine/ketamine solution was injected intraperitoneally to anesthetize the animals.…”

CD226 deficiency exacerbated intestinal immune dysregulation in mice with dinitrochlorobenzene‐induced atopic dermatitis

“…CD226 (also called DNAX accessory molecule-1 [DNAM -1]) is an activating immunoreceptor that is constitutively expressed on the cell surface of T cells, natural killer (NK) cells, monocytes/macrophages, a subset of dendritic cells, megakaryocytes/platelets, and haematopoietic precursor cells as well as endothelial cells and mast cells in human and mice [11]. CD226 physically associates with leukocyte function-associated antigen-1 (LFA-1) in NK cells and activated T cells [12].…”