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Autophagy mediated CoCrMo particle-induced peri-implant osteolysis by promoting osteoblast apoptosis.

Wang Z, Liu N, Liu K, Zhou G, Gan J, Wang Z, Shi T, He W, Wang L, Guo T, Bao N, Wang R, Huang Z, Chen J, Dong L, Zhao J, Zhang J - Autophagy (2015)

Bottom Line: Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts.Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models.Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model.

View Article: PubMed Central - PubMed

Affiliation: a Jinling Hospital; Department of Orthopaedics; State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University ; Nanjing , China.

ABSTRACT
Wear particle-induced osteolysis is the leading cause of aseptic loosening, which is the most common reason for THA (total hip arthroplasty) failure and revision surgery. Although existing studies suggest that osteoblast apoptosis induced by wear debris is involved in aseptic loosening, the underlying mechanism linking wear particles to osteoblast apoptosis remains almost totally unknown. In the present study, we investigated the effect of autophagy on osteoblast apoptosis induced by CoCrMo metal particles (CoPs) in vitro and in a calvarial resorption animal model. Our study demonstrated that CoPs stimulated autophagy in osteoblasts and PIO (particle-induced osteolysis) animal models. Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts. Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models. Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model. Collectively, these results suggest that autophagy plays a key role in CoPs-induced osteolysis and that targeting autophagy-related pathways may represent a potential therapeutic approach for treating particle-induced peri-implant osteolysis.

No MeSH data available.


Related in: MedlinePlus

Autophagy mediated the upregulation of CoPs-induced osteoblast apoptosis in vivo. (A) Immunofluorescence was performed to determine the expression of cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, cleaved CASP3 (C-CASP3); green, osteoblasts (BGLAP); blue, DAPI nuclear staining. (B) Immunofluorescence was performed to determine the colocalization of LC3 and cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, LC3; green, cleaved CASP3 (C-CASP3); blue, DAPI nuclear staining.
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f0007: Autophagy mediated the upregulation of CoPs-induced osteoblast apoptosis in vivo. (A) Immunofluorescence was performed to determine the expression of cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, cleaved CASP3 (C-CASP3); green, osteoblasts (BGLAP); blue, DAPI nuclear staining. (B) Immunofluorescence was performed to determine the colocalization of LC3 and cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, LC3; green, cleaved CASP3 (C-CASP3); blue, DAPI nuclear staining.

Mentions: We first confirmed that autophagy was induced by CoPs in osteoblasts in an animal model (Fig. S4). CoPs treatment significantly increased the expression of LC3 in osteoblasts compared with that of the control. Cotreatment with 3-MA resulted in a reduction in LC3 levels in osteoblasts. We then performed immunofluorescence staining of murine calvaria sections to examine the level of cleaved CASP3, a protein marker of apoptosis, in osteoblasts. Figure 7A indicated that the expression of cleaved CASP3 was upregulated by CoPs in osteoblasts in vivo. More importantly, the induction of cleaved CASP3 by particles was markedly inhibited by cotreatment with 3-MA. To further investigate whether the inhibition of autophagy and apoptosis were present simultaneously, we detected the colocalization of LC3 and cleaved CASP3 in osteoblasts. As shown in Figure 7B, CoPs induced the expression of LC3 and cleaved CASP3 in the same osteoblasts, and 3-MA decreased the expression of LC3, as well as cleaved CASP3. Osteoclasts play a crucial role in wear particle-induced osteolysis.1 Thus, we also performed tartrate-resistant acidic phosphatase staining, which detected osteoclasts, to examine the effect of 3-MA on osteoclastogenesis. The data demonstrated that osteoclasts were significantly increased by CoPs (Fig. S5). However, cotreatment with 3-MA resulted in only slightly decreased formation of osteoclasts (Fig. S5). The effects of 3-MA on osteoclasts were not as notable as the effects on osteoblasts. Collectively, these data suggested that autophagy mediated the increased osteoblast apoptosis in this particle-stimulated murine calvaria resorption model.Figure 7.


Autophagy mediated CoCrMo particle-induced peri-implant osteolysis by promoting osteoblast apoptosis.

Wang Z, Liu N, Liu K, Zhou G, Gan J, Wang Z, Shi T, He W, Wang L, Guo T, Bao N, Wang R, Huang Z, Chen J, Dong L, Zhao J, Zhang J - Autophagy (2015)

Autophagy mediated the upregulation of CoPs-induced osteoblast apoptosis in vivo. (A) Immunofluorescence was performed to determine the expression of cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, cleaved CASP3 (C-CASP3); green, osteoblasts (BGLAP); blue, DAPI nuclear staining. (B) Immunofluorescence was performed to determine the colocalization of LC3 and cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, LC3; green, cleaved CASP3 (C-CASP3); blue, DAPI nuclear staining.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4835204&req=5

f0007: Autophagy mediated the upregulation of CoPs-induced osteoblast apoptosis in vivo. (A) Immunofluorescence was performed to determine the expression of cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, cleaved CASP3 (C-CASP3); green, osteoblasts (BGLAP); blue, DAPI nuclear staining. (B) Immunofluorescence was performed to determine the colocalization of LC3 and cleaved CASP3 in osteoblasts. Sections of murine calvaria are presented for the animals from each group. Scale bar: 50 µm. Red, LC3; green, cleaved CASP3 (C-CASP3); blue, DAPI nuclear staining.
Mentions: We first confirmed that autophagy was induced by CoPs in osteoblasts in an animal model (Fig. S4). CoPs treatment significantly increased the expression of LC3 in osteoblasts compared with that of the control. Cotreatment with 3-MA resulted in a reduction in LC3 levels in osteoblasts. We then performed immunofluorescence staining of murine calvaria sections to examine the level of cleaved CASP3, a protein marker of apoptosis, in osteoblasts. Figure 7A indicated that the expression of cleaved CASP3 was upregulated by CoPs in osteoblasts in vivo. More importantly, the induction of cleaved CASP3 by particles was markedly inhibited by cotreatment with 3-MA. To further investigate whether the inhibition of autophagy and apoptosis were present simultaneously, we detected the colocalization of LC3 and cleaved CASP3 in osteoblasts. As shown in Figure 7B, CoPs induced the expression of LC3 and cleaved CASP3 in the same osteoblasts, and 3-MA decreased the expression of LC3, as well as cleaved CASP3. Osteoclasts play a crucial role in wear particle-induced osteolysis.1 Thus, we also performed tartrate-resistant acidic phosphatase staining, which detected osteoclasts, to examine the effect of 3-MA on osteoclastogenesis. The data demonstrated that osteoclasts were significantly increased by CoPs (Fig. S5). However, cotreatment with 3-MA resulted in only slightly decreased formation of osteoclasts (Fig. S5). The effects of 3-MA on osteoclasts were not as notable as the effects on osteoblasts. Collectively, these data suggested that autophagy mediated the increased osteoblast apoptosis in this particle-stimulated murine calvaria resorption model.Figure 7.

Bottom Line: Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts.Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models.Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model.

View Article: PubMed Central - PubMed

Affiliation: a Jinling Hospital; Department of Orthopaedics; State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University ; Nanjing , China.

ABSTRACT
Wear particle-induced osteolysis is the leading cause of aseptic loosening, which is the most common reason for THA (total hip arthroplasty) failure and revision surgery. Although existing studies suggest that osteoblast apoptosis induced by wear debris is involved in aseptic loosening, the underlying mechanism linking wear particles to osteoblast apoptosis remains almost totally unknown. In the present study, we investigated the effect of autophagy on osteoblast apoptosis induced by CoCrMo metal particles (CoPs) in vitro and in a calvarial resorption animal model. Our study demonstrated that CoPs stimulated autophagy in osteoblasts and PIO (particle-induced osteolysis) animal models. Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts. Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models. Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model. Collectively, these results suggest that autophagy plays a key role in CoPs-induced osteolysis and that targeting autophagy-related pathways may represent a potential therapeutic approach for treating particle-induced peri-implant osteolysis.

No MeSH data available.


Related in: MedlinePlus