This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury we...This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury were determined using immunohistochemistry,apoptosis assays,and auditory brainstem response.The mechanism of PRMT5 inhibition on hair cell survival was assessed using RNA-seq and Cleavage Under Targets and Tagment-quantitative polymerase chain reaction(CUT&Tag-qPCR)analyses in the HEI-OC1 cell line.Pharmacological inhibition of PRMT5 significantly alleviated cisplatin-induced damage to hair cells and spiral ganglion neurons in the cochlea and decreased apoptosis by protecting mitochondrial function and preventing the accumulation of reactive oxygen species.CUT&Tag-qPCR analysis demonstrated that inhibition of PRMT5 in HEI-OC1 cells reduced the accumulation of H4R3me2s/H3R8me2s marks at the promoter region of the Pik3ca gene,thus activating the expression of Pik3ca.These findings suggest that PRMT5 inhibitors have strong potential as agents against cisplatininduced ototoxicity and can lay the foundation for further research on treatment strategies of hearing loss.展开更多
Background:The dysregulation of Isocitrate dehydrogenase(IDH)and the subsequent production of 2-Hydroxyglutrate(2HG)may alter the expression of epigenetic proteins in Grade 4 astrocytoma.The interplay mechanism betwee...Background:The dysregulation of Isocitrate dehydrogenase(IDH)and the subsequent production of 2-Hydroxyglutrate(2HG)may alter the expression of epigenetic proteins in Grade 4 astrocytoma.The interplay mechanism between IDH,O-6-methylguanine-DNA methyltransferase(MGMT)-promoter methylation,and protein methyltransferase proteins-5(PRMT5)activity,with tumor progression has never been described.Methods:A retrospective cohort of 34 patients with G4 astrocytoma is classified into IDH-mutant and IDH-wildtype tumors.Both groups were tested for MGMT-promoter methylation and PRMT5 through methylation-specific and gene expression PCR analysis.Inter-cohort statistical significance was evaluated.Results:Both IDH-mutant WHO grade 4 astrocytomas(n=22,64.7%)and IDH-wildtype glioblastomas(n=12,35.3%)had upregulated PRMT5 gene expression except in one case.Out of the 22 IDH-mutant tumors,10(45.5%)tumors showed MGMT-promoter methylation and 12(54.5%)tumors had unmethylated MGMT.All IDH-wildtype tumors had unmethylated MGMT.There was a statistically significant relationship between MGMT-promoter methylation and IDH in G4 astrocytoma(p-value=0.006).Statistically significant differences in progression-free survival(PFS)were also observed among all G4 astrocytomas that expressed PRMT5 and received either temozolomide(TMZ)or TMZ plus other chemotherapies,regardless of their IDH or MGMT-methylation status(p-value=0.0014).Specifically,IDH-mutant tumors that had upregulated PRMT5 activity and MGMT-promoter methylation,who received only TMZ,have exhibited longer PFS.Conclusions:The relationship between PRMT5,MGMT-promoter,and IDH is not tridirectional.However,accumulation of D2-hydroxyglutarate(2-HG),which partially activates 2-OG-dependent deoxygenase,may not affect their activities.In IDH-wildtype glioblastomas,the 2HG-2OG pathway is typically inactive,leading to PRMT5 upregulation.TMZ alone,compared to TMZ-plus,can increase PFS in upregulated PRMT5 tumors.Thus,using a PRMT5 inhibitor in G4 astrocytomas may help in tumor regression.展开更多
Protein arginine methyltransferases(PRMTs)have been implicated in the progression of many diseases.Understanding substrate recognition and specificity of individual PRMT would facilitate the discovery of selective inh...Protein arginine methyltransferases(PRMTs)have been implicated in the progression of many diseases.Understanding substrate recognition and specificity of individual PRMT would facilitate the discovery of selective inhibitors towards future drug discovery.Herein,we reported the design and synthesis of bisubstrate analogues for PRMTs that incorporate a S-adenosylmethionine(SAM)analogue moiety and a tripeptide through an alkyl substituted guanidino group.Compound AH237 is a potent and selective inhibitor for PRMT4 and PRMT5 with a half-maximal inhibition concentration(IC_(50)) of 2.8 and0.42 nmol/L,respectively.Computational studies provided a plausible explanation for the high potency and selectivity of AH237 for PRMT4/5 over other 40 methyltransferases.This proof-of-principle study outlines an applicable strategy to develop potent and selective bisubstrate inhibitors for PRMTs,providing valuable probes for future structural studies.展开更多
Arabidopsis AtPRMT10 is a plant-specific type I protein arginine methyltransferase that can asymmetrically dimethylate arginine 3 of histone H4 with auto-methylation activity.Mutations of AtPRMT10 derepress FLOWERING ...Arabidopsis AtPRMT10 is a plant-specific type I protein arginine methyltransferase that can asymmetrically dimethylate arginine 3 of histone H4 with auto-methylation activity.Mutations of AtPRMT10 derepress FLOWERING LOCUS C(FLC)expression resulting in a late-flowering phenotype.Here,to further investigate the biochemical characteristics of AtPRMT10,we analyzed a series of mutated forms of the AtPRMT10 protein.We demon-strate that the conserved“VLD”residues and“double-E loop”are essential for enzymatic activity of AtPRMT10.In addition,we show that Arg54 and Cys259 of AtPRMT10,two residues unreported in animals,are also important for its enzymatic activity.We find that Arg13 of AtPRMT10 is the auto-methylation site.However,substitution of Arg13 to Lys13 does not affect its enzymatic activity.In vivo complementation assays reveal that plants expressing AtPRMT10 with VLD-AAA,E143Q or E152Q mutations retain high levels of FLC expression and fail to rescue the late-flowering phenotype of atprmt10 plants.Taken together,we conclude that the methyltransferase activity of AtPRMT10 is essential for repressing FLC expression and promoting flowering in Arabidopsis.展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.:82271158,82192865,and 82071045)Wenzhou Municipal Science and Technology Research Program(Grant No.:2021Y0681).
文摘This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury were determined using immunohistochemistry,apoptosis assays,and auditory brainstem response.The mechanism of PRMT5 inhibition on hair cell survival was assessed using RNA-seq and Cleavage Under Targets and Tagment-quantitative polymerase chain reaction(CUT&Tag-qPCR)analyses in the HEI-OC1 cell line.Pharmacological inhibition of PRMT5 significantly alleviated cisplatin-induced damage to hair cells and spiral ganglion neurons in the cochlea and decreased apoptosis by protecting mitochondrial function and preventing the accumulation of reactive oxygen species.CUT&Tag-qPCR analysis demonstrated that inhibition of PRMT5 in HEI-OC1 cells reduced the accumulation of H4R3me2s/H3R8me2s marks at the promoter region of the Pik3ca gene,thus activating the expression of Pik3ca.These findings suggest that PRMT5 inhibitors have strong potential as agents against cisplatininduced ototoxicity and can lay the foundation for further research on treatment strategies of hearing loss.
文摘Background:The dysregulation of Isocitrate dehydrogenase(IDH)and the subsequent production of 2-Hydroxyglutrate(2HG)may alter the expression of epigenetic proteins in Grade 4 astrocytoma.The interplay mechanism between IDH,O-6-methylguanine-DNA methyltransferase(MGMT)-promoter methylation,and protein methyltransferase proteins-5(PRMT5)activity,with tumor progression has never been described.Methods:A retrospective cohort of 34 patients with G4 astrocytoma is classified into IDH-mutant and IDH-wildtype tumors.Both groups were tested for MGMT-promoter methylation and PRMT5 through methylation-specific and gene expression PCR analysis.Inter-cohort statistical significance was evaluated.Results:Both IDH-mutant WHO grade 4 astrocytomas(n=22,64.7%)and IDH-wildtype glioblastomas(n=12,35.3%)had upregulated PRMT5 gene expression except in one case.Out of the 22 IDH-mutant tumors,10(45.5%)tumors showed MGMT-promoter methylation and 12(54.5%)tumors had unmethylated MGMT.All IDH-wildtype tumors had unmethylated MGMT.There was a statistically significant relationship between MGMT-promoter methylation and IDH in G4 astrocytoma(p-value=0.006).Statistically significant differences in progression-free survival(PFS)were also observed among all G4 astrocytomas that expressed PRMT5 and received either temozolomide(TMZ)or TMZ plus other chemotherapies,regardless of their IDH or MGMT-methylation status(p-value=0.0014).Specifically,IDH-mutant tumors that had upregulated PRMT5 activity and MGMT-promoter methylation,who received only TMZ,have exhibited longer PFS.Conclusions:The relationship between PRMT5,MGMT-promoter,and IDH is not tridirectional.However,accumulation of D2-hydroxyglutarate(2-HG),which partially activates 2-OG-dependent deoxygenase,may not affect their activities.In IDH-wildtype glioblastomas,the 2HG-2OG pathway is typically inactive,leading to PRMT5 upregulation.TMZ alone,compared to TMZ-plus,can increase PFS in upregulated PRMT5 tumors.Thus,using a PRMT5 inhibitor in G4 astrocytomas may help in tumor regression.
基金support from National Institute of Health(NIH)grants R01GM117275(RH)P30 CA023168(Purdue University Center for Cancer Research,West Lafayette,IN,USA)
文摘Protein arginine methyltransferases(PRMTs)have been implicated in the progression of many diseases.Understanding substrate recognition and specificity of individual PRMT would facilitate the discovery of selective inhibitors towards future drug discovery.Herein,we reported the design and synthesis of bisubstrate analogues for PRMTs that incorporate a S-adenosylmethionine(SAM)analogue moiety and a tripeptide through an alkyl substituted guanidino group.Compound AH237 is a potent and selective inhibitor for PRMT4 and PRMT5 with a half-maximal inhibition concentration(IC_(50)) of 2.8 and0.42 nmol/L,respectively.Computational studies provided a plausible explanation for the high potency and selectivity of AH237 for PRMT4/5 over other 40 methyltransferases.This proof-of-principle study outlines an applicable strategy to develop potent and selective bisubstrate inhibitors for PRMTs,providing valuable probes for future structural studies.
基金supported by the National Basic Research Program of China(Nos.2011CB915400 and 2009CB941500 to X.C.)the National Natural Science Foundation of China(Grant Nos.30930048 and 30921061 to X.C.,and 90919033 to C.L.)the Chinese Academy of Sciences(No.KSCX2-EW-Q-24-02 to C.L.)。
文摘Arabidopsis AtPRMT10 is a plant-specific type I protein arginine methyltransferase that can asymmetrically dimethylate arginine 3 of histone H4 with auto-methylation activity.Mutations of AtPRMT10 derepress FLOWERING LOCUS C(FLC)expression resulting in a late-flowering phenotype.Here,to further investigate the biochemical characteristics of AtPRMT10,we analyzed a series of mutated forms of the AtPRMT10 protein.We demon-strate that the conserved“VLD”residues and“double-E loop”are essential for enzymatic activity of AtPRMT10.In addition,we show that Arg54 and Cys259 of AtPRMT10,two residues unreported in animals,are also important for its enzymatic activity.We find that Arg13 of AtPRMT10 is the auto-methylation site.However,substitution of Arg13 to Lys13 does not affect its enzymatic activity.In vivo complementation assays reveal that plants expressing AtPRMT10 with VLD-AAA,E143Q or E152Q mutations retain high levels of FLC expression and fail to rescue the late-flowering phenotype of atprmt10 plants.Taken together,we conclude that the methyltransferase activity of AtPRMT10 is essential for repressing FLC expression and promoting flowering in Arabidopsis.
