Objective To screen for differentially expressed apoptosis-related circular RNAs(circRNAs)in osteoblasts from steroid-induced osteonecrosis of the femoral head(SONFH)and to investigate their roles and mechanisms in osteoblast apoptosis.Methods MC3T3-E1 cells were cultured and divided into two groups:Control and DEX-treated.Western blot analysis was employed to evaluate the expression levels of BCL2-Associated X protein(Bax)and B-cell lymphoma 2(Bcl-2).Cell apoptosis was assessed using TUNEL staining and flow cytometry.RNA was extracted from both normal and DEX-treated MC3T3-E1 cells,followed by RNA-seq to identify differen-tially expressed circular RNAs(circRNAs).The functions and pathways of these circRNAs were analyzed using Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG).The differentially expressed mmu_circ_0000818 was selected for further verification at the cellular level.Its chromosomal location and conservation were examined using the UCSC Genome Browser Gateway and circBase.Overexpression plasmids and small interfering RNAs(siRNAs)targeting mmu_circ_0000818 were constructed and transfected into the cells.Subsequently,apop-tosis in MC3T3-E1 cells from each group was evaluated by flow cytometry.Results Compared with the control group,the apoptosis rate of MC3T3-E1 cells was significantly increased in the DEX group(P<0.01).Differen-tially expressed circRNAs were identified based on log2foldchange(≥2)and P value(P<0.05).Relative to the control group,there were 234 differentially expressed circRNAs in the DEX group,including 138 up-regulated and 96 down-regulated circRNAs.GO and KEGG enrichment analyses of the target genes of these differentially expressed circRNAs revealed significant associations with apoptosis and the PI3K-Akt signaling pathway.qRT-PCR results demonstrated that the expression level of mmu_circ_0000818 was markedly higher in the DEX group com-pared to the control group(P<0.01).Analysis using the UCSC Genome Browser and CircBase indicated that mmu_circ_0000818,located at chromosome 17:78712463-78715086,is formed by the cyclization of exons 6-7 of the Crim1 gene and exhibits high conservation across species.Flow cytometry results indicated that knockdown of mmu_circ_0000818 attenuated DEX-induced apoptosis in MC3T3-E1 cells,while overexpression of mmu_circ_0000818 exacerbated apoptosis.Conclusions CircRNA mmu_circ_0000818 was significantly upregulated in DEX-treated MC3T3-E1 cells,and its downregulation mitigated DEX-induced apoptosis.Consequently,mmu_circ_0000818 may represent a promising therapeutic target for the prevention and treatment of SONFH.

Objective To investigate the effect and mechanism of Efferocytosis Relatived LncRNA (EFRL) on homocysteine-induced atherosclerosis in macrophage efferocytosis. Methods RAW264.7 cells were cultured in vitro, and the Control group (0 μmol/L Hcy) and Hcy intervention group (100 μmol/L Hcy) were set up. After GapmeR transfection of macrophages with Hcy intervention, EFRL knockdown negative control group (Hcy combined with LNA-NC) and EFRL knockdown group (Hcy combined with LNA-EFRL) were set up. High-throughput sequencing was applied for different expression of LncRNA MSTRG. 88917.16 (EFRL), UCSC was used to analyze its conservation, CPC and CPAT were used to analyze its ability to encode proteins, and GO and KEGG were used to analyze related biological functions. The localization of LncRNA EFRL in macrophages was analyzed by nucleoplasmic separation and RNA-FISH. Quantitative real-time PCR was used to detect the expression levels of LncRNA EFRL and its target gene SPAST in Hcy-treated macrophages. The apoptosis rate of Jurkat cells induced by UV was detected by flow cytometry. In vitro efferocytosis assay combined with immunofluorescence technique was used to analyze macrophage efferocytosis. ELISA was used to detect the levels of interleukin 1β(IL-1β) and IL-18. Results The new LncRNA MSTRG.88917.16 was identified and named EFRL(Efferocytosis Relatived LncRNA). UCSC, CPC and CPAT analyses showed that LncEFRL is highly conserved and does not have the ability to encode proteins. GO and KEGG analyses suggested that LncEFRL may be involved in macrophage efferocytosis. LncRNA EFRL was localized in the nucleus of macrophages as determined by nucleoplasmic separation and RNA-FISH. In comparison to the Control group, the expression levels of LncRNA EFRL and its target gene SPAST in the Hcy group were increased. In comparison to the Control group (0 min), the apoptosis rate of the experimental group (15, 30 min) Annexin V is more than 85%. Compared with Hcy combined with LNA-NC group, Hcy combined with LNA-EFRL group had enhanced macrophage efferocytosis and reduced levels of inflammatory factors. Compared with Hcy combined with LNA-NC group, the expression level of SPAST in Hcy combined with LNA-EFRL group was decreased. Conclusion Inhibition of EFRL expression can alleviate the process of Hcy inhibiting macrophage efferocytosis, and the mechanism is related to the regulation of the downstream target gene SPAST by EFRL.
RNA, Long Noncoding/physiology* ; Animals ; Homocysteine ; Mice ; Macrophages/drug effects* ; Humans ; RAW 264.7 Cells ; Atherosclerosis/chemically induced* ; Apoptosis/genetics* ; Phagocytosis/genetics* ; Jurkat Cells ; Interleukin-1beta/genetics* ; Efferocytosis

Objective To investigate the role of Toll-like receptor 4(TLR4)in the regulation of homocys-teine(Hcy)-induced ferroptosis in macrophages.Methods Mouse macrophage cells RAW264.7 were cultured and divided into control group,Hcy intervention group(Hcy group),and Hcy plus ferroptosis inhibitor group(Hcy+Fer-1 group).After transfection with interference fragments,macrophages were treated with Hcy,and then divided into control group,Hcy intervention group(Hcy group),TLR4 interference negative control plus Hcy intervention group(si-NC+Hcy group),and TLR4 interference plus Hcy intervention group(si-TLR4+Hcy group).Macrophages were transfected with overexpression lentivirus and treated with Hcy,then were divided into control group,Hcy intervention group(Hcy group),a TLR4 overexpression negative control plus Hcy intervention group(OE-NC+Hcy group),and a TLR4 overexpression plus Hcy intervention group(OE-TLR4+Hcy group).After 48 hours of intervention,real-time fluorescent quantitative PCR and western blot were used to detect the expression levels of TLR4 in macrophages treated with Hcy;western blot was used to detect the expression levels of ferroptosis-related proteins ACSL4,GPX4,and FTH1 in macrophages,and ferrous ion assay kit to detect the concentration of Fe2+in macrophages;reactive oxygen species(ROS)assay kit and laser confocal microscopy were used to detect the content of intracellular reactive oxygen species.Results Compared with those in the control group,the expression level of the pro-ferroptosis protein ACSL4 was increased in the Hcy group(P<0.05),while the expression levels of anti-ferroptosis proteins GPX4 and FTH1 were decreased(P<0.05);the concentration of Fe2+was increased(P<0.05),and the content of ROS was increased.Meanwhile,the protein and mRNA expres-sion levels of TLR4 were both increased in the Hcy group(P<0.05).After macrophages were transfected with TLR4 interference fragments,compared with those in the si-NC+Hcy group,the expression levels of GPX4 and FTH1 were increased(P<0.05);the expression level of ACSL4 was decreased(P<0.05);the concentration of Fe2+was decreased(P<0.05),and the content of ROS was reduced in the si-TLR4+Hcy group.After macro-phages were transfected with TLR4 overexpression lentivirus,compared with those in the OE-NC+Hcy group,the expression levels of GPX4 and FTH1 were decreased(P<0.05),and the expression level of ACSL4 was increased(P<0.05)in the OE-TLR4+Hcy group.Conclusion Hcy induces the occurrence of ferroptosis in macrophages,and Toll-like receptor 4 has a positive feedback regulatory effect on ferroptosis in macrophages.

Objective To investigate the role of Toll-like receptor 4(TLR4)in the regulation of homocys-teine(Hcy)-induced ferroptosis in macrophages.Methods Mouse macrophage cells RAW264.7 were cultured and divided into control group,Hcy intervention group(Hcy group),and Hcy plus ferroptosis inhibitor group(Hcy+Fer-1 group).After transfection with interference fragments,macrophages were treated with Hcy,and then divided into control group,Hcy intervention group(Hcy group),TLR4 interference negative control plus Hcy intervention group(si-NC+Hcy group),and TLR4 interference plus Hcy intervention group(si-TLR4+Hcy group).Macrophages were transfected with overexpression lentivirus and treated with Hcy,then were divided into control group,Hcy intervention group(Hcy group),a TLR4 overexpression negative control plus Hcy intervention group(OE-NC+Hcy group),and a TLR4 overexpression plus Hcy intervention group(OE-TLR4+Hcy group).After 48 hours of intervention,real-time fluorescent quantitative PCR and western blot were used to detect the expression levels of TLR4 in macrophages treated with Hcy;western blot was used to detect the expression levels of ferroptosis-related proteins ACSL4,GPX4,and FTH1 in macrophages,and ferrous ion assay kit to detect the concentration of Fe2+in macrophages;reactive oxygen species(ROS)assay kit and laser confocal microscopy were used to detect the content of intracellular reactive oxygen species.Results Compared with those in the control group,the expression level of the pro-ferroptosis protein ACSL4 was increased in the Hcy group(P<0.05),while the expression levels of anti-ferroptosis proteins GPX4 and FTH1 were decreased(P<0.05);the concentration of Fe2+was increased(P<0.05),and the content of ROS was increased.Meanwhile,the protein and mRNA expres-sion levels of TLR4 were both increased in the Hcy group(P<0.05).After macrophages were transfected with TLR4 interference fragments,compared with those in the si-NC+Hcy group,the expression levels of GPX4 and FTH1 were increased(P<0.05);the expression level of ACSL4 was decreased(P<0.05);the concentration of Fe2+was decreased(P<0.05),and the content of ROS was reduced in the si-TLR4+Hcy group.After macro-phages were transfected with TLR4 overexpression lentivirus,compared with those in the OE-NC+Hcy group,the expression levels of GPX4 and FTH1 were decreased(P<0.05),and the expression level of ACSL4 was increased(P<0.05)in the OE-TLR4+Hcy group.Conclusion Hcy induces the occurrence of ferroptosis in macrophages,and Toll-like receptor 4 has a positive feedback regulatory effect on ferroptosis in macrophages.

Objective To screen for differentially expressed apoptosis-related circular RNAs(circRNAs)in osteoblasts from steroid-induced osteonecrosis of the femoral head(SONFH)and to investigate their roles and mechanisms in osteoblast apoptosis.Methods MC3T3-E1 cells were cultured and divided into two groups:Control and DEX-treated.Western blot analysis was employed to evaluate the expression levels of BCL2-Associated X protein(Bax)and B-cell lymphoma 2(Bcl-2).Cell apoptosis was assessed using TUNEL staining and flow cytometry.RNA was extracted from both normal and DEX-treated MC3T3-E1 cells,followed by RNA-seq to identify differen-tially expressed circular RNAs(circRNAs).The functions and pathways of these circRNAs were analyzed using Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG).The differentially expressed mmu_circ_0000818 was selected for further verification at the cellular level.Its chromosomal location and conservation were examined using the UCSC Genome Browser Gateway and circBase.Overexpression plasmids and small interfering RNAs(siRNAs)targeting mmu_circ_0000818 were constructed and transfected into the cells.Subsequently,apop-tosis in MC3T3-E1 cells from each group was evaluated by flow cytometry.Results Compared with the control group,the apoptosis rate of MC3T3-E1 cells was significantly increased in the DEX group(P<0.01).Differen-tially expressed circRNAs were identified based on log2foldchange(≥2)and P value(P<0.05).Relative to the control group,there were 234 differentially expressed circRNAs in the DEX group,including 138 up-regulated and 96 down-regulated circRNAs.GO and KEGG enrichment analyses of the target genes of these differentially expressed circRNAs revealed significant associations with apoptosis and the PI3K-Akt signaling pathway.qRT-PCR results demonstrated that the expression level of mmu_circ_0000818 was markedly higher in the DEX group com-pared to the control group(P<0.01).Analysis using the UCSC Genome Browser and CircBase indicated that mmu_circ_0000818,located at chromosome 17:78712463-78715086,is formed by the cyclization of exons 6-7 of the Crim1 gene and exhibits high conservation across species.Flow cytometry results indicated that knockdown of mmu_circ_0000818 attenuated DEX-induced apoptosis in MC3T3-E1 cells,while overexpression of mmu_circ_0000818 exacerbated apoptosis.Conclusions CircRNA mmu_circ_0000818 was significantly upregulated in DEX-treated MC3T3-E1 cells,and its downregulation mitigated DEX-induced apoptosis.Consequently,mmu_circ_0000818 may represent a promising therapeutic target for the prevention and treatment of SONFH.

Objective To study the role of ubiquitin-conjugating enzyme 9(UBC9)in the pyroptosis of homocysteine-induced macrophages mediated by small ubiquitin-like modifier(SUMO)modification.Methods First,the effects of homocysteine at different concentrations(0 μmol/L,50 μ.mol/L,100 μmol/L,150 μmol/L and 200 μmol/L)on the viability and pyrodeath of mouse macrophages(RAW264.7)were detected by CCK-8 and Western blot.Western blot was used to detect the expression levels of UBC9,SUMO-1,and the inflammatory cytokine IL-1β in different groups of cells.qRT-PCR was used to detect the mRNA expression of UBC9 before and after RNA interference and the expression of UBC9,pyrogen-related protein,and SUMO-1 after RNA interference.Results After stimulation with 100 μmol/L homocysteine,the effect of macrophage activity was minimal,and NLRP3 and Caspase-1 were the proteins with the most obvious increase in expression(P＜0.05).Compared with the Control group,the Hcy group's expression of IL-1β and SUMO-1 was increased(P＜0.01).Compared with the Control group,the Hcy group's UBC9 protein and mRNA levels were increased(P＜0.05).The expression of NLRP3,Caspase-1,IL-1β,UBC9,and SUMO-1 was decreased in the si-UBC9+Hcy group compared with the si-NC+Hcy group(P＜0.01).Conclusions Homocysteine induces pyroptosis in macrophages,and its mechanism of action is related to the up-regulation of UBC9 to induce SUMO modification.

BACKGROUND:Ischemic postconditioning is one of the effective ways to reduce ischemia-reperfusion injury and has been more and more widely used in clinical practice in recent years,but its specific molecular mechanism has yet to be studied. OBJECTIVE:To investigate the role and mechanism of piRNA-005854 in the aging cardiomyocytes caused by hypoxic postconditioning. METHODS:In vitro,cardiomyocytes were administered 8 mg/mL D-galactose for 9 days to induce their aging.β-Galactosidase staining was used to observe the aging of cardiomyocytes.Senescent cells were treated with hypoxia/reoxygenation and hypoxic postconditioning.ELISA was utilized to detect changes in myocardial injury markers creatine kinase isoenzyme MB and lactate dehydrogenase levels.Western blot assay was applied to detect the expression changes of autophagy-related proteins LC3II,p62,ULK1 and phosphorylated ULK1 in aging cardiomyocytes.qRT-PCR was employed to determine the expression level of piRNA-005854.piRNA-005854 inhibitor and piRNA-005854 mimics were transferred into aging cardiomyocytes and followed with hypoxic postconditioning.Western blot assay was used to examine the expression of LC3II,p62,ULK1 and phosphorylated ULK1. RESULTS AND CONCLUSION:(1)D-galactose induced obvious senescence of cardiomyocytes 9 days later.(2)Compared with the normoxia group,creatine kinase isoenzyme MB and lactate dehydrogenase levels increased in the hypoxia/reoxygenation group(P<0.01);LC3 II/I expression was increased;p62 expression was decreased;ULK1 phosphorylation level was increased,and piRNA-005854 expression was increased(P<0.01).(3)Compared with the hypoxia/reoxygenation group,creatine kinase isoenzyme MB and lactate dehydrogenase levels significantly reduced in the hypoxic postconditioning group(P<0.01);LC3 II/I expression significantly decreased(P<0.05);p62 expression increased(P<0.01);ULK1 phosphorylation level decreased(P<0.05),and piRNA-005854 expression decreased(P<0.01).(4)After transfection of piRNA-005854 inhibitor,LC3II/I expression was decreased(P<0.01);the expression of p62 was increased significantly(P<0.05);the phosphorylation level of ULK1 was decreased significantly(P<0.01).After transfection of piRNA-005854 mimics,LC3II/I expression was increased significantly;the expression of p62 was decreased,and the phosphorylation level of ULK1 was increased significantly(P<0.01).(5)The results show that piRNA-005854-mediated reduction of ULK1-dependent autophagy level is a possible mechanism that hypoxic postconditioning exerts its protective effect on aging cardiomyocytes.

BACKGROUND:Increased homocysteine level induces apoptosis of human umbilical vein endothelial cells,but the mechanism remains unclear. OBJECTIVE:To investigate the role of hsa-circ-0001360 in human umbilical vein endothelial cell apoptosis induced by homocysteine. METHODS:In vitro cultured human umbilical vein endothelial cells were divided into control group,homocysteine group,interference control group,interference control + homocysteine group,hsa-circ-0001360 interference group,hsa-circ-0001360 + homocysteine interference group,overexpression control group,overexpression control + homocysteine group,hsa-circ-0001360 overexpression group and hsa-circ-0001360 + homocysteine overexpression group.All groups were treated with 100 μmol/L homocysteine.After 72 hours of intervention,the expressions of apoptosis-related proteins Bax,Bcl-2,and Caspase-3 were detected by western blot assay.The apoptotic rate was detected by flow cytometry.Quantitative real-time PCR was used to detect the expression of hsa-circ-0001360. RESULTS AND CONCLUSION:(1)Compared with the control group,the expression of Caspase-3 and Bax was significantly increased(P<0.01),and the expression of Bcl-2 was significantly decreased(P<0.01),and the apoptotic rate was significantly increased(P<0.01)in the homocysteine group.(2)Compared with control group,the expression of hsa-circ-0001360 was significantly increased in the homocysteine group(P<0.01).(3)The expression of hsa-circ-0001360 was significantly higher in the cytoplasm than that in the nucleus(P<0.01).(4)Compared with the interference control C group and interference control + homocysteine group,the expressions of Caspase-3 and Bax were significantly decreased(P<0.01),while the expression of Bcl-2 was significantly increased(P<0.01);the apoptotic rate was significantly decreased(P<0.01)in sh-hsa-circ-0001360 interference group and sh-hsa-circ-0001360 + homocysteine interference group.(5)Compared with overexpression control group and overexpression control + homocysteine group,the expressions of Caspase-3 and Bax were significantly increased(P<0.01),while the expression of Bcl-2 was significantly decreased(P<0.01);the apoptotic rate was significantly increased(P<0.01)in the hsa-circ-0001360 overexpression group and the hsa-circ-0001360 + homocysteine overexpression group.(6)In conclusion,hsa-circ-0001360 can promote the apoptosis of human umbilical vein endothelial cells induced by homocysteine.

BACKGROUND:Hyperhomocysteinemia is closely related to the function of islet β cells,but its specific molecular mechanism is not fully understood. OBJECTIVE:To investigate the role of N6 methyltransferase-like 3(METTL3)in homocysteine(Hcy)-induced autophagy of mouse islet β cells. METHODS:The 3rd and 4th generation mouse islet β cells were taken for the experiment.(1)Cell modeling and grouping:cells in control group were not treated with Hcy,while those in homocysteine group were treated with 100 μmol/L Hcy for 48 hours.(2)The mouse islet β-cells were transfected with the plasmids overexpressing Ad-METTL3 and si-METTL3 according to the instructions of LipofectamineTM 2000.Three different interfering fragments were designed,and the one with the best interfering efficiency was verified and screened by PCR.(3)After transfection,the cells were divided into control group,Hcy group,Ad-NC(negative control)+Hcy group,Ad-METTL3+Hcy group,si-NC(negative control)+Hcy group and si-METTL3+Hcy group.(4)qRT-PCR and western blot were used to detect the expression levels of METTL3 and autophagy-related proteins LC3Ⅱ/Ⅰ and p62 in cells.Insulin level was determined by ELISA to evaluate insulin secretion capacity of islet cells.Autophagy-related proteins and insulin level were detected after overexpression and interference with METTL3. RESULTS AND CONCLUSION:Compared with the control group,the expression level of LC3Ⅱ/Ⅰ was increased(P＜0.05),the expression of p62 was significantly reduced(P＜0.05),and the insulin secretion capacity was significantly decreased(P＜0.05)in the Hcy group.Compared with the control group,the protein and mRNA levels of METTL3 were reduced in the Hcy group(P＜0.05).After METTL3 silencing in islet β cells,Hcy further upregulated the expression of LC3Ⅱ/Ⅰ(P＜0.05),significantly dowregulated the expression of p62(P＜0.05),and increased the insulin level(P＜0.05).After overexpression of METTL3,Hcy significantly decreased the LC3Ⅱ/Ⅰ expression and increased the p62 expression in islet β cells(P＜0.05).To conclude,METTL3 is involved in the Hcy-induced autophagy regulation of islet β cells and plays a role in the regulation of insulin secretion.

AIM:To investigate the role of specific long noncoding RNA SLC25a6(lncSLC25a6)in homocys-teine(Hcy)-induced cuproptosis in cardiomyocytes.METHODS:Rat cardiomyocytes were cultured in vitro and divided into control group and Hcy group.After 48 h of intervention,the expression levels of cuproptosis-related proteins,ferre-doxin 1(FDX1)and heat shock protein 70(HSP70),were detected by Western blot and immunofluorescence staining.The oxidative stress state of cardiomyocytes was assessed using fluorescence staining,and the intracellular Cu2+levels were measured using a copper ion assay kit.Furthermore,the impact of Hcy on the expression of cuproptosis-related proteins in cardiomyocytes was analyzed following overexpression of lncSLC25a6.RESULTS:Compared with the control group,80 μmol/L Hcy significantly accelerated cardiomyocyte damage,with a notable underexpression of lncSLC25a6(P<0.05).Western blot results indicated that,compared with the control group,the expression level of FDX1 in the Hcy intervention group was significantly reduced(P<0.05),while the expression level of HSP70 was significantly elevated(P<0.05),and the expression level of copper ions in cardiomyocytes of the Hcy group was increased(P<0.05).Immunofluorescence staining showed a significant reduction in FDX1 fluorescence intensity and a significant increase in HSP70 fluorescence in-tensity in the Hcy group.Further overexpression of lncSLC25a6 significantly mitigated Hcy-induced cuproptosis in cardio-myocytes,resulting in elevated expression of FDX1 and reduced expression of HSP70(P<0.05).Pearson correlation analysis demonstrated that the expression level of lncSLC25a6 was negatively correlated with FDX1 protein expression(r=-0.676,P=0.046)and positively correlated with HSP70 expression(r=0.680,P=0.044).CONCLUSION:lnc-SLC25a6 significantly mitigates Hcy-induced cuproptosis in cardiomyocytes,positioning it as a potential therapeutic target for managing Hcy-induced cardiac injury.