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.

BACKGROUND:Previous studies found that the proliferative scar-specific long non-coding RNA lncRNA HSFAS is a novel biomarker that can be used in the diagnosis of hypertrophic scar,but how it functions in hypertrophic scar is not clear. OBJECTIVE:To investigate the role and mechanism of lncRNA HSFAS in hypertrophic scar.METHODS:Fresh scar tissue and surrounding normal skin tissue samples from three patients with hypertrophic scar were collected,and tissue immunofluorescence was used to detect the expression of lncRNA HSFAS in frozen sections of two skin tissues. Primary fibroblasts were isolated from proliferative scarred skin tissue and normal skin tissue and cultured by enzyme digestion method. Quantitative real-time PCR was used to detect the mRNA expression of lncRNA HSFAS in cells. The proteins bound to lncRNA HSFAS were detected by RNA pull-down combined mass spectrometry. GO and KEGG were used to analyze the main functions and pathways of lncRNA HSFAS involved in hypertrophic scar progression. The targeted binding of lncRNA HSFAS to proteins was determined by catRAPID and RPISeq website analysis. RESULTS AND CONCLUSION:Compared with normal skin tissue and fibroblasts from normal skin tissue,the expression of lncRNA HSFAS in human hypertrophic scar tissue and primary fibroblasts from hypertrophic scar tissue was significantly increased (P<0.05). There were 510 proteins clearly bound to lncRNA HSFAS by RNA pull-down combined mass spectrometry. The results of GO and KEGG analyses showed that these proteins were mainly involved in RNA splicing and processing,chromosome synthesis and separation,and cell cycle. Among them,the proteins involved in RNA splicing and processing included scaffold attachment factor B2 and DICER1,and the binding fraction with lncRNA HSFAS was higher. The results of bioinformatics analysis showed that lncRNA HSFAS was bound to scaffold attachment factor B2 and DICER1 proteins. To conclude,lncRNA HSFAS may affect gene expression by interacting with scaffold attachment factor B2 and DICER1 proteins to regulate RNA splicing and processing modification,thus promoting the occurrence and development of hypertrophic scar.

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 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.

BACKGROUND:Previous studies found that the proliferative scar-specific long non-coding RNA lncRNA HSFAS is a novel biomarker that can be used in the diagnosis of hypertrophic scar,but how it functions in hypertrophic scar is not clear. OBJECTIVE:To investigate the role and mechanism of lncRNA HSFAS in hypertrophic scar.METHODS:Fresh scar tissue and surrounding normal skin tissue samples from three patients with hypertrophic scar were collected,and tissue immunofluorescence was used to detect the expression of lncRNA HSFAS in frozen sections of two skin tissues. Primary fibroblasts were isolated from proliferative scarred skin tissue and normal skin tissue and cultured by enzyme digestion method. Quantitative real-time PCR was used to detect the mRNA expression of lncRNA HSFAS in cells. The proteins bound to lncRNA HSFAS were detected by RNA pull-down combined mass spectrometry. GO and KEGG were used to analyze the main functions and pathways of lncRNA HSFAS involved in hypertrophic scar progression. The targeted binding of lncRNA HSFAS to proteins was determined by catRAPID and RPISeq website analysis. RESULTS AND CONCLUSION:Compared with normal skin tissue and fibroblasts from normal skin tissue,the expression of lncRNA HSFAS in human hypertrophic scar tissue and primary fibroblasts from hypertrophic scar tissue was significantly increased (P<0.05). There were 510 proteins clearly bound to lncRNA HSFAS by RNA pull-down combined mass spectrometry. The results of GO and KEGG analyses showed that these proteins were mainly involved in RNA splicing and processing,chromosome synthesis and separation,and cell cycle. Among them,the proteins involved in RNA splicing and processing included scaffold attachment factor B2 and DICER1,and the binding fraction with lncRNA HSFAS was higher. The results of bioinformatics analysis showed that lncRNA HSFAS was bound to scaffold attachment factor B2 and DICER1 proteins. To conclude,lncRNA HSFAS may affect gene expression by interacting with scaffold attachment factor B2 and DICER1 proteins to regulate RNA splicing and processing modification,thus promoting the occurrence and development of hypertrophic scar.

Objective To study the effect of DNA methyltransferase 1(DNMT1)on sm-like protein-4(LSM4)in hepatocyte apoptosis in mice induced with Hcy.Methods 12 ApoE-/-mice were divided into two groups:normal diet(ND,n=6)and high methionine diet(HMD,n=6)groups.Normal hepatocytes of NCTC1469 were divided into a normal group(control,0 μL/L Hcy),Hcy intervention group(Hcy,100 μL/L Hcy),NC siRNA-transfected control group(si-NC group,0 μmol/L Hcy),LSM4 siRNA-transfected group(si-LSM4 group,0 μmol/L Hcy),DNMT1 siRNA-transfected group(si-DNMT1 group,0 μmol/L Hcy),NC siRNA-transfected Hcy intervention group(Hcy+si-NC group,100 μmol/L Hcy),LSM4 siRNA-transfected Hcy intervention group(Hcy+si-LSM4 group,100 μmol/L Hcy),and DNMT1 siRNA-transfected Hcy intervention group(Hcy+si-DNMT1 group,100 μmol/L Hcy).Analysis of the expression of LSM4 in various tissues was conducted using the NCBI database.Quantitative real-time PCR(qRT-PCR)and Western blot were used to detect differences in LSM4 protein expression in mouse tissues(HMD and ND)and hepatocytes(control and Hcy).Western blot was used to detect the expression of Bcl2-associated X(Bax)and B-cell lymphoma-2(Bcl-2).The cell apoptosis rate in the Control,Hcy,Hcy+si-NC,and Hcy+si-LSM4 groups were detected by flow cytometry.MethPrimer online software was used to analyze the CpG islands of LSM4 promoter region.The expression of LSM4 in the Hcy+si-DNMT1 group was detected by qRT-PCR and Western blot.Results The expression of LSM4 in HMD,Hcy group was higher than that in the ND and Control group(P＜0.05).Bax protein expression was significantly higher,but Bcl-2 was significantly lower in Hcy group compared with those of the Control group(P＜0.05).The expression of Bax protein was significantly lower,but the level of Bcl-2 was significantly higher in the Hcy+si-LSM4 group compared with those in the Hcy+si-NC group(P＜0.05).The cell apoptosis rate in the Hcy group was higher than that in the Control group(P＜0.05),while the apoptosis rate in the Hcy+si-LSM4 group was lower than that in the Hcy+si-NC group(P＜0.05).MethPrimer database analysis showed that the promoter region of LSM4 was GC-rich,and there was one CpG island.Compared with the Hcy+si-NC group,the Hcy+si-DNMT1 group's expression of LSM4 protein was increased(P＜0.05).Conclusions DNMT1 regulates LSM4 hypomethylation to increase its expression,thereby promoting Hcy-induced apoptosis of mouse hepatocytes.

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.

Objective To investigate the effect of miR-22-3p on pyroptosis of vascular smooth muscle cells(VSMCs)induced by homocysteine(Hcy).Methods Human VSMCs were cultured in vitro and divided into a Control group(0 μmol/L Hey)and a Hey group(100 μmol/L Hey).After intervention,expression levels of pro Caspase-1,gasdermin D(GSDMD),N-GSDMD,and NLR family pyrin domain containing 3(NLRP3)were detected by Western blot.MiR-22-3p expression was determined by quantitative real-time reverse-transcription polymerase chain reaction.Interleukin(IL)-1 β and IL-18 levels in the supernatant were measured by enzyme-linked immunosorbent assay.Cells were also transfected with control miR-22-3p(miR-22-3p-NC),miR-22-3p-mimic,and miR-22-3p-inhibitor,to observe the effects on VSMC pyroptosis induced by Hcy.Results Expression levels of pro Caspase-1,GSDMD,N-GSDMD,and NLRP3 in VSMCs were increased(P＜0.05),IL-1 β and IL-18 levels were increased(P＜0.01),and the relative expression level of miR-22-3p was reduced(P＜0.01)in the Hcy group compared with the Control group.Transfection with miR-22-3p-mimic significantly decreased the expression levels of pro Caspase-1,GSDMD,N-GSDMD,and NLRP3 in VSMCs(P＜0.01),and significantly decreased levels of IL-1β and IL-18(P＜0.01),while transfection with miR-22-3p-inhibitor significantly increased the expression levels of pro Caspase-1,GSDMD,N-GSDMD,and NLRP3 in VSMCs(P＜0.01)and significantly increased the levels of IL-1β and IL-18(P＜0.05).Conclusions MiR-22-3p may delay Hcy-induced VSMC pyroptosis.