ABSTRACT
BACKGROUND:Apoptosis is involved in the formation of degenerative joint diseases.Therefore,anti-chondrocyte apoptosis may be an effective way to treat osteoarthritis.Neferine has a wide range of pharmacological activities including anti-inflammatory,anti-tumor and anti-apoptotic activities,and its effect on chondrocyte apoptosis is not clear. OBJECTIVE:To investigate the effect of neferine on chondrocyte apoptosis induced by interleukin-1β and elucidate its possible mechanism. METHODS:(1)The rat chondrocytes at logarithmical stage were taken and intervened in five groups.The control group was cultured routinely.The model group was routinely cultured for 24 hours after treatment with interleukin-1β for 2 hours.The low-,medium-,and high-dose groups were treated with interleukin-1β for 2 hours and then cultured with 5,10,and 20 μmol/L neferine for 24 hours,respectively.At the end of culture,cell apoptosis,chondroglycoprotein 39 and type Ⅱ collagen levels in cell supernatants,mRNA and protein expression of apoptosis-related proteins,and mRNA and protein expression of proteins related to the protein kinase R-like endoplasmic reticulum kinase(PERK)/activating transcription factor 4(ATF4)signaling pathway were detected.(2)Rat chondrocytes at logarithmic growth period were taken and divided into four groups:control group and model group were treated with the same intervention as above,drug group was treated with interleukin-1β for 2 hours and then cultured with 20 μmol/L neferine for 24 hours,and activator group was treated with interleukin-1β for 2 hours and then cultured with 20 μmol/L neferine and CCT020312,an activator of PERK/ATF4 signaling pathway,for 24 hours.At the end of culture,cell proliferation was detected by cell counting kit-8 assay,apoptosis was detected by flow cytometry,and mRNA and protein expressions of apoptosis-related proteins and PERK/ATF4 signaling pathway-related proteins were detected. RESULTS AND CONCLUSION:(1)Compared with the control group,the model group showed increased apoptosis(P<0.05),decreased proliferative activity(P<0.05),increased level of chondroglycoprotein 39(P<0.05),decreased level of type Ⅱ collagen(P<0.05),decreased mRNA and protein expression of Bcl-2 protein(P<0.05),increased mRNA and protein expression of Bax protein,increased caspase-3 mRNA expression,increased Cleaved-caspase-3 protein expression(P<0.05),increased mRNA expression of PERK,ATF4,and C/EBP homologous protein(P<0.05),and increased protein expression of p-PERK,ATF4,and C/EBP homologous protein(P<0.05).Compared with the model group,neferine reversed the above effects of interleukin-1β on chondrocytes in a concentration-dependent manner.(2)Compared with the drug group,the activator group showed increased apoptosis(P<0.05),decreased proliferative activity(P<0.05),elevated mRNA expression of caspase-3,ATF4,and C/EBP homologous protein(P<0.05),and elevated protein expression of Cleaved-caspase-3,ATF4,and C/EBP homologous protein(P<0.05).(3)To conclude,neferine inhibits interleukin-1β-induced chondrocyte apoptosis and enhances cell proliferation activity,and the mechanism of action may be related to blocking the PERK/ATF4 signaling pathway in the endoplasmic reticulum.
ABSTRACT
During normal aging, the number of dopaminergic (DA) neurons in the substantia nigra progressively diminishes, although massive DA neuronal loss is a hallmark sign of Parkinson's disease. Unfortunately, there is little known about the molecular events involved in age-related DA neuronal loss. In this study, we found that (1) the level of parkin was decreased in the cerebellum, brain stem, substantia nigra, and striatum of aged mice, (2) diaminodiphenyl sulfone (DDS) restored the level of parkin, (3) DDS prevented age-dependent DA neuronal loss, and (4) DDS protected SH-SY5Y cells from 1-methyl-4-phenylpyridinium and hydrogen peroxide. Furthermore, pretreatment and/or post-treatment of DDS in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease model attenuated DA neuronal loss and restored motor behavior. DDS transcriptionally activated parkin via protein kinase RNA-like endoplasmic reticulum kinase-activating transcription factor 4 signaling and DDS not only failed to induce parkin expression but also failed to rescue SH-SY5Y cells from 1-methyl-4-phenylpyridinium in the absence of ATF4. Herein, we demonstrated for the first time that DDS increased parkin level and served as a neuroprotective agent for age-dependent DA neuronal loss. Thus, DDS may be a potential therapeutic agent for age-related neurodegeneration.