Objective To investigate the effect of 1, 25-(OH)₂-VitD3 (VitD3) on renal tubuleinterstitial fibrosis in diabetic kidney disease. Methods NRK-52E renal tubular epithelial cells were divided into control group (5.5 mmol/L glucose medium treatment), high glucose group (25 mmol/L glucose medium treatment) and high glucose with added VitD3 group (25 mmol/L glucose medium combined with 10^-8 mmol/L VitD3). The mRNA and protein expression of Snail1, SMAD3, SMAD4, α-SMA and E-cadherin in NRK-52E cells were detected by real-time quantitative PCR and Western blot analysis respectively. The expression and localization of Snail1, SMAD3 and SMAD4 were detected by immunofluorescence cytochemical staining. The binding of Snail1 with SMAD3/SMAD4 complex to the promoter of Coxsackie-adenovirus receptor (CAR) was detected by chromatin immunoprecipitation. The interaction among Snail1, SMAD3/SMAD4 and E-cadherin were detected by luciferase assay. Small interfering RNA (siRNA) was used to inhibit the expression of Snail1 and SMAD4, and the expression of mRNA of E-cadherin was detected by real-time quantitative PCR. SD rats were randomly divided into control group, DKD group and VitD3-treated group. DKD model was established by injection of streptozotocin (STZ) in DKD group and VitD3-treated group. After DKD modeling, VitD3-treated group was given VitD3 (60 ng/kg) intragastric administration. Control group and DKD group were given normal saline intragastric administration. In the DKD group and VitD3-treated group, insulin (1-2 U/kg) was injected subcutaneously to control blood glucose for 8 weeks. The mRNA and protein levels of Snail1, SMAD3, SMAD4, α-SMA and E-cadherin in renal tissues were detected by real-time quantitative PCR and Western blot analysis respectively. Immunohistochemistry was used to detect the expression and localization of Snail1, SMAD3, SMAD4, α-SMA and E-cadherin in renal tissue. Results Compared with the control group, the mRNA and protein expressions of Snail1, SMAD3, SMAD4 and α-SMA in NRK-52E cells cultured with high glucose and in DKD renal tissues were up-regulated, while E-cadherin expression was down-regulated. After the intervention of VitD3, the expression levels of Snail1, SMAD3, SMAD4, α-SMA and E-cadherin in the DKD model improved to be close to those in the control group. Chromatin immunoprecipitation showed that Snail1 and SMAD3/SMAD4 bound to CAR promoter IV, while VitD3 prevented Snail1 and SMAD3/SMAD4 from binding to CAR promoter IV. Luciferase assay confirmed the interaction among Snail1, SMAD3/SMAD4 and E-cadherin. After the mRNA of Snail1 and SMAD4 was inhibited by siRNA, the expression of E-cadherin induced by high glucose was up-regulated. Conclusion VitD3 could inhibit the formation of Snail1-SMAD3/SMAD4 complex and alleviate the renal tubulointerstitial fibrosis in DKD.
Animals ; Rats ; Cadherins/genetics* ; Diabetes Mellitus/pathology* ; Diabetic Nephropathies/pathology* ; Epithelial-Mesenchymal Transition ; Fibrosis/pathology* ; Glucose/pharmacology* ; Kidney/pathology* ; Rats, Sprague-Dawley ; RNA, Messenger ; RNA, Small Interfering ; Transforming Growth Factor beta1/metabolism* ; Vitamin D/pharmacology*

OBJECTIVES: To investigate the effects and molecular mechanisms of asiatic acid on β-cell function in type 2 diabetes mellitus (T2DM). METHODS: The T2DM model was established by high fat diet and streptozotocin injection in ICR mice, and the effects of asiatic acid on glucose regulation were investigated in model mice. The islets were isolated from palmitic acid-treated diabetic mice. ELISA was used to detect the glucose-stimulated insulin secretion, tumor necrosis factor (TNF)-α and interleukin (IL)-6. ATP assay was applied to measure ATP production, and Western blotting was used to detect protein expression of mature β cell marker urocortin (Ucn) 3 and mitofusin (Mfn) 2. The regulatory effects of asiatic acid on glucose-stimulated insulin secretion (GSIS) and Ucn3 expression were also investigated after siRNA interference with Mfn2 or treatment with TNF-α. RESULTS: Asiatic acid with the dose of 25 mg·kg^－1·d^－1 had the best glycemic control in T2DM mice and improved the homeostasis model assessment β index. Asiatic acid increased the expression of Mfn2 and Ucn3 protein and improved the GSIS function of diabetic β cells in vitro and in vivo (both P<0.05). Moreover, it improved the ATP production of islets of T2DM mice in vitro (P<0.05). Interfering Mfn2 with siRNA blocked the up-regulation of Ucn3 and GSIS induced by asiatic acid. Asiatic acid inhibited islet TNF-α content and increased Mfn2 and Ucn3 protein expression inhibited by TNF-α. CONCLUSIONS Asiatic acid improves β cell insulin secretion function in T2DM mice by maintaining the β cell maturity, which may be related to the TNF-α/Mfn2 pathway.
Mice ; Animals ; Insulin Secretion ; Diabetes Mellitus, Type 2/drug therapy* ; Islets of Langerhans/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Insulin/therapeutic use* ; Diabetes Mellitus, Experimental ; Mice, Inbred ICR ; Glucose/therapeutic use* ; Interleukin-6/metabolism* ; RNA, Small Interfering/pharmacology* ; Adenosine Triphosphate ; GTP Phosphohydrolases/therapeutic use*

OBJECTIVES: To investigate the effect and mechanism of lipid nanoparticle (LNP) delivery of small interfering RNA (siRNA) targeting Cyp2e1 gene on subacute alcoholic liver injury in mice. METHODS: siRNA targeting Cyp2e1 gene was encapsulated in LNP (si-Cyp2e1 LNP) by microfluidic technique and the resulting LNPs were characterized. The optimal dose of si-Cyp2e1 LNP administration was screened. Forty female C57BL/6N mice were randomly divided into blank control group, model control group, si-Cyp2e1 LNP group, LNP control group and metadoxine group. The subacute alcoholic liver injury mouse model was induced by ethanol feeding for 10 d plus ethanol gavage for the last 3 d. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and the superoxide dismutase (SOD) activity as well as malondialdehyde, reactive oxygen species, glutathione, triacylglycerol, total cholesterol contents in liver tissue were measured in each group, and liver index was calculated. The expression of genes related to oxidative stress, lipid synthesis and inflammation in each group of mice were measured by realtime RT-PCR. RESULTS: Compared with the model control group, the levels of liver index, serum ALT, AST activities, malondialdehyde, reactive oxygen species, triacylglycerol, total cholesterol contents in liver tissue decreased, but the SOD activity as well as glutathione increased in the si-Cyp2e1 LNP group (all P<0.01). Hematoxylin-eosin staining result showed disorganized hepatocytes with sparse cytoplasm and a large number of fat vacuoles and necrosis in the model control group, while the si-Cyp2e1 LNP group had uniformly sized and arranged hepatocytes with normal liver tissue morphology and structure. Oil red O staining result showed si-Cyp2e1 LNP group had lower fat content of the liver compared to the model control group (P<0.01), and no fat droplets accumulated. Anti-F4/80 monoclonal antibody fluorescence immunohistochemistry showed that the si-Cyp2e1 LNP group had lower cumulative optical density values compared to the model control group (P<0.01) and no significant inflammatory reaction. Compared with the model control group, the expression of catalytic genes P47phox, P67phox and Gp91phox were reduced (all P<0.01), while the expression of the antioxidant enzyme genes Sod1, Gsh-rd and Gsh-px were increased (all P<0.01). The mRNA expression of the lipid metabolism genes Pgc-1α and Cpt1 were increased (all P<0.01) and the lipid synthesis-related genes Srebp1c, Acc and Fasn were decreased (all P<0.01); the expression of liver inflammation-related genes Tgf-β, Tnf-α and Il-6 were decreased (all P<0.01). CONCLUSIONS The si-Cyp2e1 LNP may attenuate subacute alcoholic liver injury in mice mainly by reducing reactive oxygen levels, increasing antioxidant activity, blocking oxidative stress pathways and reducing ethanol-induced steatosis and inflammation.
Animals ; Female ; Mice ; Antioxidants/metabolism* ; Cholesterol/metabolism* ; Ethanol/pharmacology* ; Glutathione/pharmacology* ; Inflammation ; Lipids/pharmacology* ; Liver ; Malondialdehyde/pharmacology* ; Mice, Inbred C57BL ; Oxidative Stress ; Reactive Oxygen Species/metabolism* ; RNA, Small Interfering/pharmacology* ; Superoxide Dismutase ; Triglycerides/metabolism* ; Cytochrome P-450 CYP2E1/metabolism*

OBJECTIVE: To investigate the influence and mechanism of atorvastatin on glycolysis of adriamycin resistant acute promyelocytic leukemia (APL) cell line HL-60/ADM. METHODS: HL-60/ADM cells in logarithmic growth phase were treated with different concentrations of atorvastatin, then the cell proliferation activity was measured by CCK-8 assay, the apoptosis was detected by flow cytometry, the glycolytic activity was checked by glucose consumption test, and the protein expressions of PTEN, p-mTOR, PKM2, HK2, P-gp and MRP1 were detected by Western blot. After transfection of PTEN-siRNA into HL-60/ADM cells, the effects of low expression of PTEN on atorvastatin regulating the behaviors of apoptosis and glycolytic metabolism in HL-60/ADM cells were further detected. RESULTS: CCK-8 results showed that atorvastatin could inhibit the proliferation of HL-60/ADM cells in a concentration-dependent and time-dependent manner (r=0.872, r=0.936), and the proliferation activity was inhibited most significantly when treated with 10 μmol/L atorvastatin for 24 h, which was decreased to (32.3±2.18)%. Flow cytometry results showed that atorvastatin induced the apoptosis of HL-60/ADM cells in a concentration-dependent manner (r=0.796), and the apoptosis was induced most notably when treated with 10 μmol/L atorvastatin for 24 h, which reached to (48.78±2.95)%. The results of glucose consumption test showed that atorvastatin significantly inhibited the glycolytic activity of HL-60/ADM cells in a concentration-dependent and time-dependent manner (r=0.915, r=0.748), and this inhibition was most strikingly when treated with 10 μmol/L atorvastatin for 24 h, reducing the relative glucose consumption to (46.53±1.71)%. Western blot indicated that the expressions of p-mTOR, PKM2, HK2, P-gp and MRP1 protein were decreased in a concentration-dependent manner (r=0.737, r=0.695, r=0.829, r=0.781, r=0.632), while the expression of PTEN protein was increased in a concentration-dependent manner (r=0.531), when treated with different concentrations of atorvastatin for 24 h. After PTEN-siRNA transfected into HL-60/ADM cells, it showed that low expression of PTEN had weakened the promoting effect of atorvastatin on apoptosis and inhibitory effect on glycolysis and multidrug resistance. CONCLUSION Atorvastatin can inhibit the proliferation, glycolysis, and induce apoptosis of HL-60/ADM cells. It may be related to the mechanism of increasing the expression of PTEN, inhibiting mTOR activation, and decreasing the expressions of PKM2 and HK2, thus reverse drug resistance.
Humans ; Atorvastatin/pharmacology* ; PTEN Phosphohydrolase/pharmacology* ; Sincalide/metabolism* ; Drug Resistance, Neoplasm/genetics* ; TOR Serine-Threonine Kinases/metabolism* ; Leukemia, Promyelocytic, Acute/drug therapy* ; Doxorubicin/pharmacology* ; Apoptosis ; RNA, Small Interfering/pharmacology* ; Glycolysis ; Glucose/therapeutic use* ; Cell Proliferation

OBJECTIVE: To study the role of apolipoprotein E (APOE) in regulating endometrial cancer metastasis and explore the signaling pathway in the regulatory mechanism. METHODS: Human endometrial cancer cell line HEC-1B was transfected with a control siRNA (siCtrl) or a specific siRNA targeting APOE (siAPOE) or with either pEGFP-N1 plasmid or an APOEoverexpressing plasmid. The changes in migration, proliferation, apoptosis and cell cycle of the transfected cells were examined using wound healing assay, Transwell migration assay, MTT assay, flow cytometry, and Hoechst staining. The activity of the ERK/MMP9 signaling pathway in the transfected cells was assessed using RT-qPCR and Western blotting. The expression level of APOE in clinical specimens of endometrial cancer tissues were detected using immunohistochemistry and its correlation with differentiation of endometrial cancer tissues was analyzed. RESULTS: Wound healing assay and Transwell migration assay showed that compared with those in siCtrl group, HEC-1B cells transfected with siAPOE showed significantly reduced migration ability (P < 0.05), whereas APOE overexpression significantly promoted the migration of the cells (P < 0.05). Neither APOE knockdown nor overexpression produced significant effects on HEC-1B cell proliferation as shown by MTT assay and flow cytometry. Hoechst staining revealed that transfection with siAPOE did not significantly affect apoptosis of HEC-1B cells. APOE knockdown obviously reduced and APOE overexpression enhanced ERK phosphorylation and MMP9 expression in HEC-1B cells (P < 0.05). Treatment with U0126 partially reversed the effects of APOE overexpression on ERK phosphorylation, migration and MMP9 expression in HEC-1B cells (P < 0.05). APOE is highly expressed in clinical samples of endometrial cancer tissues as compared with the adjacent tissues. CONCLUSION APOE is highly expressed in endometrial cancer tissues to promote cancer cell migration by enhancing ERK phosphorylation and MMP9 expression.
Female ; Humans ; Matrix Metalloproteinase 9/metabolism* ; Cell Line, Tumor ; Signal Transduction ; Endometrial Neoplasms/genetics* ; Cell Proliferation ; Apoptosis ; Cell Movement ; RNA, Small Interfering ; Apolipoproteins E ; Apolipoproteins/pharmacology*

The present study was aimed to investigate the effects of circRNA-0028171 on the apoptosis of vascular endothelial cells induced by arsenic trioxide (As₂O₃). Human umbilical vein endothelial cells (HUVECs) were treated with 0-15 μmol/L As₂O₃ for 24 h. Then, cellular viability was measured by MTT assay. The expression levels of circRNA-0028171, Bcl-2 and Bax mRNA were detected by real-time quantitative PCR. Bcl-2/Bax protein ratio was detected by Western blot. Whether circRNA-0028171 was involved in the regulation of HUVECs by As₂O₃ was investigated by transfection with overexpression plasmid of circRNA-0028171 and siRNA. The results showed that compared with the control group, As₂O₃ group showed decreased cellular viability, reduced Bcl-2/Bax mRNA and protein ratios, and significantly lower expression of circRNA-0028171. Overexpression of circRNA-0028171 inhibited apoptosis of HUVECs induced by As₂O₃. Knockdown of circRNA-0028171 by siRNA promoted As₂O₃-induced apoptosis in HUVECs. These results suggest that circRNA-0028171 is involved in the vascular endothelial cell apoptosis induced by As₂O₃.
Humans ; Arsenic Trioxide/pharmacology* ; RNA, Circular ; bcl-2-Associated X Protein/metabolism* ; RNA, Small Interfering/metabolism* ; Apoptosis ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Human Umbilical Vein Endothelial Cells/metabolism* ; RNA, Messenger/metabolism*

Human salivary histatin 1 (Hst1) exhibits a series of cell-activating properties, such as promoting cell spreading, migration, and metabolic activity. We recently have shown that fluorescently labeled Hst1 (F-Hst1) targets and activates mitochondria, presenting an important molecular mechanism. However, its regulating signaling pathways remain to be elucidated. We investigated the influence of specific inhibitors of G protein-coupled receptors (GPCR), endocytosis pathways, extracellular signal-regulated kinases 1/2 (ERK1/2) signaling, p38 signaling, mitochondrial respiration and Na+/K+-ATPase activity on the uptake, mitochondria-targeting and -activating properties of F-Hst1. We performed a siRNA knockdown (KD) to assess the effect of Sigma-2 receptor (S2R) /Transmembrane Protein 97 (TMEM97)-a recently identified target protein of Hst1. We also adopted live cell imaging to monitor the whole intracellular trafficking process of F-Hst1. Our results showed that the inhibition of cellular respiration hindered the internalization of F-Hst1. The inhibitors of GPCR, ERK1/2, phagocytosis, and clathrin-mediated endocytosis (CME) as well as siRNA KD of S2R/TMEM97 significantly reduced the uptake, which was accompanied by the nullification of the promoting effect of F-Hst1 on cell metabolic activity. Only the inhibitor of CME and KD of S2R/TMEM97 significantly compromised the mitochondria-targeting of Hst1. We further showed the intracellular trafficking and targeting process of F-Hst1, in which early endosome plays an important role. Overall, phagocytosis, CME, GPCR, ERK signaling, and S2R/TMEM97 are involved in the internalization of Hst1, while only CME and S2R/TMEM97 are critical for its subcellular targeting. The inhibition of either internalization or mitochondria-targeting of Hst1 could significantly compromise its mitochondria-activating property.
Endocytosis/physiology* ; Histatins/pharmacology* ; Humans ; Membrane Proteins ; Mitochondria/metabolism* ; RNA, Small Interfering/pharmacology* ; Receptors, G-Protein-Coupled/metabolism* ; Receptors, sigma

Objective: To investigate the effect of P62 on the migration and motility of human epidermal cell line HaCaT in high glucose microenvironment and its possible molecular mechanism, so as to explore the mechanism of refractory diabetic foot wound healing. Methods: The method of experimental research was used. HaCaT cells in logarithmic growth phase was taken for experiment. The cells were collected and divided into normal control group (culture solution containing glucose with final molarity of 5.5 mmol/L) and high glucose (culture solution containing glucose with final molarity of 30.0 mmol/L) 24 h group, high glucose 48 h group, and high glucose 72 h group according to the random number table (the same grouping method below). The cells in normal control group were routinely cultured for 72 h, cells in high glucose 72 h group were cultured with high glucose for 72 h, cells in high glucose 48 h group were routinely cultured for 24 h then cultured with high glucose for 48 h, cells in high glucose 24 h group were routinely cultured for 48 h then cultured with high glucose for 24 h. Then the protein expression of P62 was detected by Western blotting. The cells were collected and divided into normal control group and high glucose group. After being correspondingly cultured for 48 h as before, the protein expression of P62 was detected by immunofluorescence method (indicated as green fluorescence). The cells were collected and divided into negative control small interfering RNA (siRNA) group, P62-siRNA-1 group, P62-siRNA-2 group, and P62-siRNA-3 group, and transfected with the corresponding reagents. At post transfection hour (PTH) 72, the protein expression of P62 was detected by Western blotting. The cells were collected and divided into normal glucose+negative control siRNA group, normal glucose+P62-siRNA group, high glucose+negative control siRNA group, and high glucose+P62-siRNA group. After the corresponding treatment, the protein expression of P62 was detected by Western blotting at PTH 72 h, the cell migration rate was detected and calculated at 24 h after scratching by scratch test, with the number of samples being 9; and the range of cell movement was observed and the trajectory velocity was calculated within 3 h under the living cell workstation, with the number of samples being 76, 75, 80, and 79 in normal glucose+negative control siRNA group, normal glucose+P62-siRNA group, high glucose+negative control siRNA group, and high glucose+P62-siRNA group, respectively. The cells were collected and divided into normal glucose+phosphate buffered solution (PBS) group, high glucose+PBS group, and high glucose+N-acetylcysteine (NAC) group. After the corresponding treatment, the protein expression of P62 at 48 h of culture was detected by Western blotting and immunofluorescence method, respectively. Except for scratch test and cell motility experiment, the number of samples was all 3 in the rest experiments. Data were statistically analyzed with one-way analysis of variance and least significant difference test. Results: Compared with the protein expression in normal control group, the protein expressions of P62 of cells in high glucose 24 h group, high glucose 48 h group, and high glucose 72 h group were significantly increased (P<0.01). At 48 h of culture, the green fluorescence of P62 of cells in high glucose group was stronger than that in normal control group. At PTH 72, compared with the protein expression in negative control siRNA group, the protein expressions of P62 of cells in P62-siRNA-1 group, P62-siRNA-2 group, and P62-siRNA-3 group were significantly decreased (P<0.01). At PTH 72, compared with the protein expression in normal glucose+negative control siRNA group, the protein expression of P62 of cells in normal glucose+P62-siRNA group was significantly decreased (P<0.01), while the protein expression of P62 of cells in high glucose+negative control siRNA group was significantly increased (P<0.01); compared with the protein expression in high glucose+negative control siRNA group, the protein expression of P62 of cells in high glucose+P62-siRNA group was significantly decreased (P<0.01). At 24 h after scratching, compared with (55±7)% in normal glucose+negative control siRNA group, the cell migration rate in normal glucose+P62-siRNA group was significantly increased ((72±14)%, P<0.01), while the cell migration rate in high glucose+negative control siRNA group was significantly decreased ((37±7)%, P<0.01); compared with that in high glucose+negative control siRNA group, the cell migration rate in high glucose+P62-siRNA group was significantly increased ((54±10)%, P<0.01). Within 3 h of observation, the cell movement range in high glucose+negative control siRNA group was smaller than that in normal glucose+negative control siRNA group, while the cell movement range in normal glucose+P62-siRNA group was larger than that in normal glucose+negative control siRNA group, and the cell movement range in high glucose+P62-siRNA group was larger than that in high glucose+negative control siRNA group. Compared with that in normal glucose+negative control siRNA group, the cell trajectory speed in normal glucose+P62-siRNA group was significantly increased (P<0.01), while the cell trajectory speed in high glucose+negative control siRNA group was significantly decreased (P<0.01); compared with that in high glucose+negative control siRNA group, the cell trajectory speed in high glucose+P62-siRNA group was significantly increased (P<0.01). At 48 h of culture, compared with that in normal glucose+PBS group, the protein expression of P62 of cells in high glucose+PBS group was significantly increased (P<0.01); compared with that in high glucose+PBS group, the protein expression of P62 of cells in high glucose+NAC group was significantly decreased (P<0.01). At 48 h of culture, the green fluorescence of P62 of cells in high glucose+PBS group was stronger than that in normal glucose+PBS group, while the green fluorescence of P62 of cells in high glucose+NAC group was weaker than that in high glucose+PBS group. Conclusions: In HaCaT cells, high glucose microenvironment can promote the protein expression of P62; knockdown of P62 protein can promote the migration and increase the mobility of HaCaT cells; and the increase of reactive oxygen species in high glucose microenvironment may be the underlying mechanism for the increase of P62 expression.
Humans ; RNA, Small Interfering/genetics* ; Cell Line ; Epidermis ; Glucose/pharmacology* ; Epidermal Cells

The purpose of this paper was to study the transcriptional regulation of nuclear respiratory factor 1 (NRF1) on nuclear factor kappa B (NF-κB), a key molecule in lipopolysaccharide (LPS)-induced lung epithelial inflammation, and to clarify the mechanism of NRF1-mediated inflammatory response in lung epithelial cells. In vivo, male BALB/c mice were treated with NRF1 siRNA, followed with LPS (4 mg/kg) or 0.9% saline through respiratory tract, and sacrificed 48 h later. Expression levels of NRF1, NF-κB p65 and its target genes were detected by Western blot and real-time PCR. Nuclear translocation of NRF1 or p65 was measured by immunofluorescent technique. In vitro, L132 cells were transfected with NRF1 siRNA or treated with BAY 11-7082 (5 μmol/L) for 24 h, followed with treatment of 1 mg/L LPS for 6 h. Cells were lysed for detections of NRF1, NF-κB p65 and its target genes as well as the binding sites of NRF1 on RELA (encoding NF-κB p65) promoter by chromatin immunoprecipitation assay (ChIP). Results showed that LPS stimulated NRF1 and NF-κB p65. Pro-inflammatory factors including interleukin-1β (IL-1β) and IL-6 were significantly increased both in vivo and in vitro. Obvious nuclear translocations of NRF1 and p65 were observed in LPS-stimulated lung tissue. Silencing NRF1 resulted in a decrease of p65 and its target genes both in vivo and in vitro. In addition, BAY 11-7082, an inhibitor of NF-κB, significantly repressed the inflammatory responses induced by LPS without affecting NRF1 expression. Furthermore, it was proved that NRF1 had three binding sites on RELA promoter region. In summary, NRF1 is involved in LPS-mediated acute lung injury through the transcriptional regulation on NF-κB p65.
Acute Lung Injury/genetics* ; Animals ; Lipopolysaccharides/pharmacology* ; Male ; Mice ; NF-kappa B/metabolism* ; Nuclear Respiratory Factor 1/genetics* ; RNA, Small Interfering ; Transcription Factor RelA/metabolism*

Osteoarthritis (OA) is a prevalent joint disease with no effective treatment strategies. Aberrant mechanical stimuli was demonstrated to be an essential factor for OA pathogenesis. Although multiple studies have detected potential regulatory mechanisms underlying OA and have concentrated on developing novel treatment strategies, the epigenetic control of OA remains unclear. Histone demethylase JMJD3 has been reported to mediate multiple physiological and pathological processes, including cell differentiation, proliferation, autophagy, and apoptosis. However, the regulation of JMJD3 in aberrant force-related OA and its mediatory effect on disease progression are still unknown. In this work, we confirmed the upregulation of JMJD3 in aberrant force-induced cartilage injury in vitro and in vivo. Functionally, inhibition of JMJD3 by its inhibitor, GSK-J4, or downregulation of JMJD3 by adenovirus infection of sh-JMJD3 could alleviate the aberrant force-induced chondrocyte injury. Mechanistic investigation illustrated that aberrant force induces JMJD3 expression and then demethylates H3K27me3 at the NR4A1 promoter to promote its expression. Further experiments indicated that NR4A1 can regulate chondrocyte apoptosis, cartilage degeneration, extracellular matrix degradation, and inflammatory responses. In vivo, anterior cruciate ligament transection (ACLT) was performed to construct an OA model, and the therapeutic effect of GSK-J4 was validated. More importantly, we adopted a peptide-siRNA nanoplatform to deliver si-JMJD3 into articular cartilage, and the severity of joint degeneration was remarkably mitigated. Taken together, our findings demonstrated that JMJD3 is flow-responsive and epigenetically regulates OA progression. Our work provides evidences for JMJD3 inhibition as an innovative epigenetic therapy approach for joint diseases by utilizing p5RHH-siRNA nanocomplexes.
Cartilage, Articular/pathology* ; Chondrocytes/metabolism* ; Down-Regulation ; Epigenesis, Genetic ; Humans ; Jumonji Domain-Containing Histone Demethylases/metabolism* ; Nuclear Receptor Subfamily 4, Group A, Member 1/metabolism* ; Osteoarthritis/pathology* ; RNA, Small Interfering/pharmacology*