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Journal of Pediatric Urology Feb 2021Hypospadias is the second most common congenital malformation in males. Although the aetiology of hypospadias is not clear, it is generally thought to be affected by...
BACKGROUND
Hypospadias is the second most common congenital malformation in males. Although the aetiology of hypospadias is not clear, it is generally thought to be affected by both genetic and environmental endocrine-disrupting factors that affect the development of the urethra, leading to deformity.
OBJECTIVE
To investigate the difference in expression of the transcription factor Mafb in hypospadias and normal penile tissues and to assess whether it is related to the occurrence of hypospadias.
STUDY DESIGN
Penile tissue was obtained from children with hypospadias who underwent surgical repair at the Children's Hospital of Chongqing Medical University. Patients diagnosed with undescended testicles, intersex status or endocrine abnormalities were excluded from the study. Twenty-five cases with hypospadias (average 3.5 years old) and 15 cases with circumcisions (as control) (average 5 years old) were included in this study. Real-time quantitative polymerase chain reaction, Immunochemistry and Western blot were used to detect the expression of Mafb.
RESULTS
Mafb mRNA expressions in the prepuce of cases with hypospadias was significantly reduced compared with that in the controls [(1.179 ± 0.1275), (0.6652 ± 0.07506), p < 0.05)]. Hypospadias cases also showed decreased Mafb protein expression in the preputial subcutaneous mesenchymal cell layer. Mafb protein levels were significantly decreased in those with hypospadias compared with controls [(1.932 ± 0.1139), (1.006 ± 0.03312), p < 0.05]. However, no such differences were found in Mafb expression between subjects with mild and severe hypospadias.
DISCUSSION
Compared to the normal foreskin, expression of the Mafb gene was down-regulated at both mRNA and protein levels, which was consistent with our RNA-seq sequencing results in Diethylhexyl phthalate (DEHP)-induced hypospadias rats. This study is the first to report abnormal expression of Mafb in the preputial tissue of hypospadias cases. An in-depth study of the relationship between Mafb and cell proliferation, apoptosis, and urethra development may reveal the pathogenesis of hypospadias.
CONCLUSION
Expression of the Mafb gene and protein in the foreskin of children with hypospadias is lower than that in normal foreskin. We postulate that such abnormal expression of the Mafb gene may be related to the occurrence of hypospadias and that this abnormal expression may affect the development of the urethra during the embryonic period.
Topics: Animals; Child; Foreskin; Humans; Hypospadias; MafB Transcription Factor; Male; Oncogene Proteins; Penis; Rats; Urethra
PubMed: 33268316
DOI: 10.1016/j.jpurol.2020.10.006 -
Cancers May 2021Multiple myeloma (MM) is an incurable hematologic malignancy characterized by the clonal expansion of malignant plasma cells within the bone marrow. Activator Protein-1... (Review)
Review
Multiple myeloma (MM) is an incurable hematologic malignancy characterized by the clonal expansion of malignant plasma cells within the bone marrow. Activator Protein-1 (AP-1) transcription factors (TFs), comprised of the JUN, FOS, ATF and MAF multigene families, are implicated in a plethora of physiologic processes and tumorigenesis including plasma cell differentiation and MM pathogenesis. Depending on the genetic background, the tumor stage, and cues of the tumor microenvironment, specific dimeric AP-1 complexes are formed. For example, AP-1 complexes containing Fra-1, Fra-2 and B-ATF play central roles in the transcriptional control of B cell development and plasma cell differentiation, while dysregulation of AP-1 family members c-Maf, c-Jun, and JunB is associated with MM cell proliferation, survival, drug resistance, bone marrow angiogenesis, and bone disease. The present review article summarizes our up-to-date knowledge on the role of AP-1 family members in plasma cell differentiation and MM pathophysiology. Moreover, it discusses novel, rationally derived approaches to therapeutically target AP-1 TFs, including protein-protein and protein-DNA binding inhibitors, epigenetic modifiers and natural products.
PubMed: 34066181
DOI: 10.3390/cancers13102326 -
Science Bulletin Sep 2021Though promoting ferroptosis can reduce cisplatin resistance in tumor cells, ferroptosis and cisplatin resistance in bladder urothelial carcinoma (BUC) following long...
Though promoting ferroptosis can reduce cisplatin resistance in tumor cells, ferroptosis and cisplatin resistance in bladder urothelial carcinoma (BUC) following long non-coding RNAs (lncRNAs) is largely unknown. Here, we found the highly expressed lncRNA MAF transcription factor G antisense RNA 1 (MAFG-AS1) in BUC, and its inhibition increased the sensitivity of BUC cells to cisplatin by promoting ferroptosis. Mechanically, binding to iron chaperone poly(rC)-binding protein 2 (PCBP2) facilitated the recruitments of MAFG-AS1 to deubiquitinase ubiquitin carboxyl-terminal hydrolase isozyme L5 (UCHL5), thus stabilizing PCBP2 protein itself. Then PCBP2 was confirmed to interact with ferroportin 1 (FPN1), an iron export protein, leading to inhibition of ferroptosis. Moreover, the expression of MAFG-AS1 was regulated by the transcriptional factor MAFG. Interestingly, MAFG-AS1 stimulated MAFG transcription by recruiting histone acetyltransferase p300 (EP300) to promote the histone 3 at lysine 27 (H3K27ac) at genomic locus of MAFG, forming a MAFG-AS1/MAFG positive feedback loop. In patient samples, higher expression of MAFG-AS1 and MAFG in BUC tissues was significantly correlated with T status and N status, such that MAFG-AS1, MAFG, and the combination of the two were independent prognostic indicators and chemotherapy sensitivity predictive biomarkers for BUC patients. These findings suggest that inhibition of MAFG-AS1 and MAFG can increase the sensitivity of BUC cells to cisplatin through promoting ferroptosis, indicating the novel chemotherapy sensitivity biomarkers and therapeutic target for BUC.
Topics: Humans; Carcinoma, Transitional Cell; Cisplatin; Drug Resistance, Neoplasm; Feedback; Ferroptosis; MafG Transcription Factor; Repressor Proteins; RNA-Binding Proteins; Urinary Bladder; Urinary Bladder Neoplasms
PubMed: 36654385
DOI: 10.1016/j.scib.2021.01.027 -
Cell Communication and Signaling : CCS Feb 2021The oncogenic transcript factor c-Maf is stabilized by the deubiquitinase Otub1 and promotes myeloma cell proliferation and confers to chemoresistance. Inhibition of the...
BACKGROUND
The oncogenic transcript factor c-Maf is stabilized by the deubiquitinase Otub1 and promotes myeloma cell proliferation and confers to chemoresistance. Inhibition of the Otub1/c-Maf axis is a promising therapeutic target, but there are no inhibitors reported on this specific axis.
METHODS
A luciferase assay was applied to screen potential inhibitors of Otub1/c-Maf. Annexin V staining/flow cytometry was applied to evaluate cell apoptosis. Immunoprecipitation was applied to examine protein ubiquitination and interaction. Xenograft models in nude mice were used to evaluate anti-myeloma activity of AVT.
RESULTS
Acevaltrate (AVT), isolated from Valeriana glechomifolia, was identified based on a bioactive screen against the Otub1/c-Maf/luciferase system. AVT disrupts the interaction of Otub1/c-Maf thus inhibiting Otub1 activity and leading to c-Maf polyubiquitination and subsequent degradation in proteasomes. Consistently, AVT inhibits c-Maf transcriptional activity and downregulates the expression of its target genes key for myeloma growth and survival. Moreover, AVT displays potent anti-myeloma activity by triggering myeloma cell apoptosis in vitro and impairing myeloma xenograft growth in vivo but presents no marked toxicity.
CONCLUSIONS
The natural product AVT inhibits the Otub1/c-Maf axis and displays potent anti-myeloma activity. Given its great safety and efficacy, AVT could be further developed for MM treatment. Video Abstract.
Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line; Cell Survival; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Female; Humans; Iridoids; Mice, Inbred BALB C; Mice, Nude; Multiple Myeloma; Proto-Oncogene Proteins c-maf; Mice
PubMed: 33627137
DOI: 10.1186/s12964-020-00676-w -
Inhibition of the deubiquitinase USP5 leads to c-Maf protein degradation and myeloma cell apoptosis.Cell Death & Disease Sep 2017The deubiquitinase USP5 stabilizes c-Maf, a key transcription factor in multiple myeloma (MM), but the mechanisms and significance are unclear. In the present study,...
The deubiquitinase USP5 stabilizes c-Maf, a key transcription factor in multiple myeloma (MM), but the mechanisms and significance are unclear. In the present study, USP5 was found to interact with c-Maf and prevented it from degradation by decreasing its polyubiquitination level. Specifically, the 308th and 347th lysine residues in c-Maf were critical for USP5-mediated deubiquitination and stability. There are five key domains in the USP5 protein and subsequent studies revealed that the cryptic ZnF domain and the C-box domain interacted with c-Maf but the UBA1/UBA2 domain partly increased its stability. Notably, MafA and MafB are also members of the c-Maf family, however, USP5 failed to deubiquitinate MafA, suggesting its substrate specificity. In the functional studies, USP5 was found to promoted the transcriptional activity of c-Maf. Consistent with the high level of c-Maf protein in MM cells, USP5 was also highly expressed. When USP5 was knocked down, c-Maf underwent degradation. Interestingly, USP5 silence led to apoptosis of MM cells expressing c-Maf but not MM cells lacking c-Maf, indicating c-Maf is a key factor in USP5-mediated MM cell proliferation and survival. Consistent with this finding, WP1130, an inhibitor of several Dubs including USP5, suppressed the transcriptional activity of c-Maf and induced MM cell apoptosis. When c-Maf was overexpressed, WP1130-induced MM cell apoptosis was abolished. Taken together, these findings suggest that USP5 regulates c-Maf stability and MM cell survival. Targeting the USP5/c-Maf axis could be a potential strategy for MM treatment.
Topics: Apoptosis; Endopeptidases; Gene Knockdown Techniques; HEK293 Cells; Humans; Lysine; Molecular Targeted Therapy; Multiple Myeloma; Polyubiquitin; Protein Binding; Protein Domains; Protein Stability; Proteolysis; Proto-Oncogene Proteins c-maf; Structure-Activity Relationship; Transcription, Genetic; Ubiquitination
PubMed: 28933784
DOI: 10.1038/cddis.2017.450 -
American Journal of Physiology.... Apr 2020Liver sinusoidal endothelial cells (LSECs) are the first liver cells to encounter waste macromolecules, pathogens, and toxins in blood. LSECs are highly specialized to...
Liver sinusoidal endothelial cells (LSECs) are the first liver cells to encounter waste macromolecules, pathogens, and toxins in blood. LSECs are highly specialized to mediate the clearance of these substances via endocytic scavenger receptors and are equipped with fenestrae that mediate the passage of macromolecules toward hepatocytes. Although some transcription factors (TFs) are known to play a role in LSEC specialization, information about the specialized LSEC signature and its transcriptional determinants remains incomplete.Based on a comparison of liver, heart, and brain endothelial cells (ECs), we established a 30-gene LSEC signature comprising both established and newly identified markers, including 7 genes encoding TFs. To evaluate the LSEC TF regulatory network, we artificially increased the expression of the 7 LSEC-specific TFs in human umbilical vein ECs. Although Zinc finger E-box-binding protein 2, homeobox B5, Cut-like homolog 2, and transcription factor EC (TCFEC) had limited contributions, musculoaponeurotic fibrosarcoma (C-MAF), GATA binding protein 4 (GATA4), and MEIS homeobox 2 (MEIS2) emerged as stronger inducers of LSEC marker expression. Furthermore, a combination of C-MAF, GATA4, and MEIS2 showed a synergistic effect on the increase of LSEC signature genes, including liver/lymph node-specific ICAM-3 grabbing non-integrin () (or C-type lectin domain family member M (), mannose receptor C-Type 1 (), legumain (), G protein-coupled receptor 182 (), Plexin C1 (), and solute carrier organic anion transporter family member 2A1 (). Accordingly, L-SIGN, MRC1, pro-LGMN, GPR182, PLXNC1, and SLCO2A1 protein levels were elevated by this combined overexpression. Although receptor-mediated endocytosis was not significantly induced by the triple TF combination, it enhanced binding to E2, the hepatitis C virus host-binding protein. We conclude that C-MAF, GATA4, and MEIS2 are important transcriptional regulators of the unique LSEC fingerprint and LSEC interaction with viruses. Additional factors are however required to fully recapitulate the molecular, morphological, and functional LSEC fingerprint. Liver sinusoidal endothelial cells (LSECs) are the first liver cells to encounter waste macromolecules, pathogens, and toxins in the blood and are highly specialized. Although some transcription factors are known to play a role in LSEC specialization, information about the specialized LSEC signature and its transcriptional determinants remains incomplete. Here, we show that Musculoaponeurotic Fibrosarcoma (C-MAF), GATA binding protein 4 (GATA4), and Meis homeobox 2 (MEIS2) are important transcriptional regulators of the unique LSEC signature and that they affect the interaction of LSECs with viruses.
Topics: Animals; Endothelial Cells; Gene Expression Regulation; Genetic Markers; Humans; Liver; Male; Organ Specificity; Rats; Transcriptome
PubMed: 32116021
DOI: 10.1152/ajpgi.00215.2019 -
Cancer Letters Sep 2022Multiple myeloma (MM) is a hematologic malignancy derived from clonal expansion of plasma cells within the bone marrow and it may progress to the extramedullary region...
Multiple myeloma (MM) is a hematologic malignancy derived from clonal expansion of plasma cells within the bone marrow and it may progress to the extramedullary region in late stage of the disease course. c-Maf, an oncogenic zipper leucine transcription factor, is overexpressed in more than 50% MM cell lines and primary species in association with chromosomal translocation, aberrant signaling transduction and modulation of stability. By triggering the transcription of critical genes including CCND2, ITGB7, CCR1, ARK5, c-Maf promotes MM progress, proliferation, survival and chemoresistance. Notably, c-Maf is usually expressed at the embryonic stage to promote cell differentiation but less expressed in healthy adult cells. c-Maf has long been proposed as a promising therapeutic target of MM and a panel of small molecule compounds have been identified to downregulate c-Maf and display potent anti-myeloma activities. In the current article, we take a concise summary on the advances in c-Maf biology, pathophysiology, and targeted drug discovery in the potential treatment of MM.
Topics: Bone Marrow; Carcinogenesis; Humans; MafF Transcription Factor; Multiple Myeloma; Plasma Cells
PubMed: 35700821
DOI: 10.1016/j.canlet.2022.215791 -
The Journal of Clinical Investigation Oct 2021Liver tumor-initiating cells (TICs) are involved in liver tumorigenesis, metastasis, drug resistance, and relapse, but the regulatory mechanisms of liver TICs are...
Liver tumor-initiating cells (TICs) are involved in liver tumorigenesis, metastasis, drug resistance, and relapse, but the regulatory mechanisms of liver TICs are largely unknown. Here, we have identified a functional circular RNA, termed circRNA activating MAFF (cia-MAF), that is robustly expressed in liver cancer and liver TICs. cia-MAF-KO primary cells and cia-maf-KO liver tumors harbor decreased ratios of TICs, and display impaired liver tumorigenesis, self-renewal, and metastatic capacities. In contrast, cia-MAF overexpression drives liver TIC propagation, self-renewal, and metastasis. Mechanistically, cia-MAF binds to the MAFF promoter, recruits the TIP60 complex to the MAFF promoter, and finally promotes MAFF expression. Loss of cia-MAF function attenuates the combination between the TIP60 complex and the MAFF promoter. MAFF is highly expressed in liver tumors and liver TICs, and its antisense oligo (ASO) has therapeutic potential in treating liver cancer without MAFA/MAFG gene copy number alterations (CNAs). This study reveals an additional layer for liver TIC regulation as well as circRNA function, and provides an additional target for eliminating liver TICs, especially for liver tumors without MAFA/MAFG gene CNAs.
Topics: Animals; Cell Self Renewal; Humans; Liver Neoplasms; Lysine Acetyltransferase 5; MafF Transcription Factor; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neoplastic Stem Cells; Promoter Regions, Genetic; RNA, Circular
PubMed: 34403373
DOI: 10.1172/JCI148020 -
Circulation May 2021Coronary artery disease (CAD) is a multifactorial condition with both genetic and exogenous causes. The contribution of tissue-specific functional networks to the...
Transcription Factor MAFF (MAF Basic Leucine Zipper Transcription Factor F) Regulates an Atherosclerosis Relevant Network Connecting Inflammation and Cholesterol Metabolism.
BACKGROUND
Coronary artery disease (CAD) is a multifactorial condition with both genetic and exogenous causes. The contribution of tissue-specific functional networks to the development of atherosclerosis remains largely unclear. The aim of this study was to identify and characterize central regulators and networks leading to atherosclerosis.
METHODS
Based on several hundred genes known to affect atherosclerosis risk in mouse (as demonstrated in knockout models) and human (as shown by genome-wide association studies), liver gene regulatory networks were modeled. The hierarchical order and regulatory directions of genes within the network were based on Bayesian prediction models, as well as experimental studies including chromatin immunoprecipitation DNA-sequencing, chromatin immunoprecipitation mass spectrometry, overexpression, small interfering RNA knockdown in mouse and human liver cells, and knockout mouse experiments. Bioinformatics and correlation analyses were used to clarify associations between central genes and CAD phenotypes in both human and mouse.
RESULTS
The transcription factor MAFF (MAF basic leucine zipper transcription factor F) interacted as a key driver of a liver network with 3 human genes at CAD genome-wide association studies loci and 11 atherosclerotic murine genes. Most importantly, expression levels of the low-density lipoprotein receptor (LDLR) gene correlated with MAFF in 600 CAD patients undergoing bypass surgery (STARNET [Stockholm-Tartu Atherosclerosis Reverse Network Engineering Task]) and a hybrid mouse diversity panel involving 105 different inbred mouse strains. Molecular mechanisms of MAFF were tested in noninflammatory conditions and showed positive correlation between MAFF and LDLR in vitro and in vivo. Interestingly, after lipopolysaccharide stimulation (inflammatory conditions), an inverse correlation between MAFF and LDLR in vitro and in vivo was observed. Chromatin immunoprecipitation mass spectrometry revealed that the human CAD genome-wide association studies candidate BACH1 (BTB domain and CNC homolog 1) assists MAFF in the presence of lipopolysaccharide stimulation with respective heterodimers binding at the MAF recognition element of the LDLR promoter to transcriptionally downregulate LDLR expression.
CONCLUSIONS
The transcription factor was identified as a novel central regulator of an atherosclerosis/CAD-relevant liver network. triggered context-specific expression of and other genes known to affect CAD risk. Our results suggest that is a missing link between inflammation, lipid and lipoprotein metabolism, and a possible treatment target.
Topics: Animals; Atherosclerosis; Cholesterol; DNA-Binding Proteins; Disease Models, Animal; Humans; Inflammation; MafF Transcription Factor; Male; Mice; Mice, Knockout; Nuclear Proteins
PubMed: 33626882
DOI: 10.1161/CIRCULATIONAHA.120.050186 -
The Journal of Biological Chemistry Feb 2020The Maf proteins, including c-Maf, MafA, and MafB, are critical transcription factors in myelomagenesis. Previous studies demonstrated that Maf proteins are processed by...
The Maf proteins, including c-Maf, MafA, and MafB, are critical transcription factors in myelomagenesis. Previous studies demonstrated that Maf proteins are processed by the ubiquitin-proteasome pathway, but the mechanisms remain elusive. This study applied MS to identify MafB ubiquitination-associated proteins and found that the ubiquitin-specific protease USP7 was present in the MafB interactome. Moreover, USP7 also interacted with c-Maf and MafA and blocked their polyubiquitination and degradation. Consistently, knockdown of USP7 resulted in Maf protein degradation along with increased polyubiquitination levels. The action of USP7 thus promoted Maf transcriptional activity as evidenced by luciferase assays and by the up-regulation of the expression of Maf-modulated genes. Furthermore, USP7 was up-regulated in myeloma cells, and it was negatively associated with the survival of myeloma patients. USP7 promoted myeloma cell survival, and when it was inhibited by its specific inhibitor P5091, myeloma cell lines underwent apoptosis. These results therefore demonstrated that USP7 is a deubiquitinase of Maf proteins and promotes MM cell survival in association with Maf stability. Given the significance of USP7 and Maf proteins in myeloma genesis, targeting the USP7/Maf axle is a potential strategy to the precision therapy of MM.
Topics: Apoptosis; Carcinogenesis; Cell Proliferation; Cell Survival; Female; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Maf Transcription Factors, Large; MafB Transcription Factor; Male; Multiple Myeloma; Polyubiquitin; Progression-Free Survival; Proteolysis; Proto-Oncogene Proteins c-maf; Thiophenes; Ubiquitin-Specific Peptidase 7; Ubiquitination
PubMed: 31822558
DOI: 10.1074/jbc.RA119.010724