Mechanism of Piezo1 protein induced apoptosis of osteoarthritis chondrocytes through MAPK/ERK5 signal pathway / 中华骨科杂志

ABSTRACT

Objective To investigate whether the new mechanically-activated (MA) cation channel Piezo 1 protein can cause the apoptosis of human chondrocytes under compressive loading,using a Flexercell unit by activating MAPK/ERK5 signal pathway.Methods Primary human chondrocytes were isolated,cultured,and then subjected to the static compressive loading for 2 h,12 h,24.h and 48 h,respectively.The GsMTx4,which is the special inhibitor of the Piezo1 protein and the BIX02188,which is the inhibitor of the ERK5 served as the inhibitor group.The immunofluorescence was used to locate the expression of the Piezo 1 protein.The expressions of Piezo1 and ERK5 were assessed by reverse transcription-polymerase chain reaction (RT-PCR),as well as the apoptosis gene B cell lymphoma/leukemia-2 (Bcl-2),Bcl-associated X protein (Bax) and Bcl-associated death promoter (BAD).In addition,Piezo1 inhibitor,GsMTx4,was used to block the MA cation channel Piezo1,served as the inhibitor group.AVPI was used to detect the apoptosis of the OA chondrocytes.Results The location of the Piezo1 was expressed in nucleus and cytoplasm of chondrocytes.The expression of the Piezo1,ERK5,BAD,and Bax mRNA in the OA chondrocytes is weak.The 12 h stretch force group was significant increased,and the 24 h stretch force group was the highest expression.However,the expression of the 48 h group was decreasing.The expression of the Bcl-2 in the 12 h group was decreasing,and the 12 h stretch force group was the lowest expression while the 24 h stretch force group was increasing.In the GsMTx4 group,the expression of the Piezo1,ERK5,BAD,Bax was decreasing while the Bcl-2 was increasing.In the BIX02188 group,the expression of the ERKS,BAD,Bax was increasing while the Bcl-2 was decreasing,while the expression of the Piezo1 was not change.The result of AV-PI shown that the 2 h stretch force group increased early stage of apoptosis.The 12 h stretch force group increased late stage of apoptosis,and the 24 h stretch force group's apoptotic rate was the highest.However,the apoptotic rate of the 48 h group was lower than the 24 h stretch force group.The GsMTx4 could inhibit the late stage of apoptosis.Conclusion Piezo 1 plays an important role in the apoptosis of human chondrocyte through the MAPK/ERK5 signal pathway.