miR-219a-5p inhibits the pyroptosis in knee osteoarthritis by inactivating the NLRP3 signaling via targeting FBXO3.

This work was to identify the function and mechanism of miR-219a-5p in regulating knee osteoarthritis (KOA). Rat fibroblast-like synoviocytes (FLSs) were isolated to construct KOA cell model by lipopolysaccharide and adenosine triphosphate treatment. miR-219a-5p and FBXO3 expression in FLSs was modulated by transfection. Flow cytometry was executed to research FLSs apoptosis. Caspase-1 and IL-1β expression in FLSs was researched by immunofluorescence. The binding between miR-219a-5p and FBXO3 was identified by dual luciferase reporter gene assay. KOA rat model and miR-219a-5p up-modulation KOA rat model were constructed. Step size of rats was analyzed. Knee joints of rats were experienced Safranin O-fast green staining to evaluate the knee joint injury. FBXO3, pyroptosis-associated proteins, and IL-1β and IL-18 expression in FLSs and articular cartilage tissues of rats were assessed by Western blot, qRT-PCR and Enzyme-linked immunosorbent assay. KOA cell model had higher apoptosis percentage, expression of pyroptosis-associated proteins, and IL-1β and IL-18 level. miR-219a-5p up-modulation decreased the above indicators, whereas miR-219a-5p down-modulation increased the above indicators. FBXO3 expression was directly repressed by miR-219a-5p. Loss of FBXO3 suppressed the above indicators. FBXO3 counteracted the suppression of miR-219a-5p on the above indicators. miR-219a-5p agomir attenuated knee joint injury, increased step size of KOA rats, and reduced FBXO3, pyroptosis-associated proteins and level of IL-1β and IL-18 in the articular cartilage tissues of KOA rats. miR-219a-5p suppressed the pyroptosis in KOA by inactivating the NLRP3 signaling via targeting FBXO3, which might be a promising target for ameliorating KOA in the clinic.

Wang Q ，Huang PY ，Wu JG ，Zhang TQ ，Li LF ，Huang LD ，Yu YM ，Wang MH ，He J ... -  《-》

MiR-223-3p inhibits inflammation and pyroptosis in monosodium urate-induced rats and fibroblast-like synoviocytes by targeting NLRP3.

Down-regulated miR-223-3p was found in rheumatoid arthritis. This study aimed to further explore the level and role of miR-223-3p in gout arthritis (GA). After monosodium urate (MSU)-induced GA rat and fibroblast-like synoviocytes (FLSs) models were established, the rat paw volume and gait score were documented and the FLSs were transfected with miR-223-3p mimic/inhibitor or NLR family pyrin domain containing 3 (NLRP3) over-expression plasmids. The MiR-223-3p target was found through bioinformatics and the dual-luciferase reporter. The rat joint pathological damage was observed by hematoxylin and eosin staining. The levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and articular elastase in rats were detected by enzyme-linked immunosorbent assay (ELISA). The viability and pyroptosis of FLSs were detected by methyl thiazolyl tetrazolium (MTT) and flow cytometry. The expressions of miR-223-3p, NLRP3, cleaved caspase-1, IL-1β, apoptosis-associated speck-like protein (AS) and cleaved N-terminal gasdermin D (GSDMD) in FLSs or rat synovial tissues were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, Western blot or immunohistochemistry analysis. MSU increased the paw volume, gait score, inflammation in synovial tissues and increased the levels of IL-1β, TNF-α and articular elastase in rats. MSU decreased the viability and increased the pyroptosis of FLSs, up-regulated the expression of NLRP3, ASC, cleaved caspase-1, cleaved N-terminal GSDM, and IL-1β, and down-regulated miR-223-3p expression in synovial tissues of rat joints and FLSs. MiR-223-3p mimic reversed the effect of MSU on lowering cell viability, increasing pyroptosis in FLSs, while miR-223-3p inhibitor further enhanced the effect of MSU on FLSs. NLRP3 was a target of miR-223-3p. Also, NLRP3 over-expression reversed the effects of miR-223-3p on MSU-induced FLSs. MiR-223-3p inhibited pyroptosis in MSU-induced rats and FLSs by targeting NLRP3.

Tian J ，Zhou D ，Xiang L ，Liu X ，Zhang H ，Wang B ，Xie B ... -  《-》

miR-155 inhibits chondrocyte pyroptosis in knee osteoarthritis by targeting SMAD2 and inhibiting the NLRP3/Caspase-1 pathway.

Knee osteoarthritis (KOA) is based on degenerative pathological changes. miR-155 is involved in regulating KOA. This study estimated the mechanism of miR-155 in mouse KOA chondrocytes. Mouse KOA chondrocyte model was established by lipopolysaccharide (LPS) induction and identified through Collagen II immunofluorescence staining and toluidine blue staining. LPS-induced KOA chondrocytes were transfected with miR-155 inhibitor or/and si-SMAD2, followed by the evaluation of miR-155 expression, pyroptosis, the SMAD2/NLRP3/Caspase-1 axis-related protein levels, IL-1β and 1L-18 levels, and cell viability by RT-qPCR, FAM-FLICA Caspase-1 Detection Kit, Western blot, ELISA, and MTT assays, respectively. The binding sites between miR-155 and SMAD2 were predicted online and the binding relationship was verified by dual-luciferase assay. miR-155 was highly-expressed in LPS-induced KOA chondrocytes. miR-155 knockdown increased cell viability and decreased pyroptotic chondrocytes, and Caspase-1, 1L-1β and 1L-18 levels. miR-155 targeted SMAD2. SMAD2 knockdown partially annulled the effects of miR-155 silencing on inhibiting KOA chondrocyte pyroptosis. NLRP3 pathway was activated in LPS-induced KOA chondrocytes, inhibited after miR-155 knockdown, and activated again after further SMAD2 knockdown. NLRP3 inhibition suppressed Caspase-1, IL-1β, and IL-18 levels and chondrocyte pyroptosis and increased cell viability. miR-155 knockdown inhibited the NLRP3/Caspase-1 pathway by targeting SMAD2, thus inhibiting mouse KOA chondrocyte pyroptosis.

Li G ，Xiu L ，Li X ，Ma L ，Zhou J ... -  《Journal of Orthopaedic Surgery and Research》

MicroRNA-140-5p represses chondrocyte pyroptosis and relieves cartilage injury in osteoarthritis by inhibiting cathepsin B/Nod-like receptor protein 3.

Zhang L ，Qiu J ，Shi J ，Liu S ，Zou H ... -  《-》

[Effect of electroacupuncture on pyroptosis of synovial tissues in rats with knee osteoarthritis].

Yu YN ，Tang CL ，Guo X ，Xie YH ... -  《-》