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Changes in the absolute protein amounts of transcription factors are important for regulating gene expression during cell differentiation and in responses to changes in the cellular and extracellular environment. However, few studies have focused on the absolute quantification of mammalian transcription factors. In this study, we established an absolute quantification method for the transcription factors BACH1 and BACH2, which are expressed in B cells and regulated by direct heme binding. The method used purified recombinant proteins as controls in western blotting and was applied to mouse naïve B cells in the spleen, as well as activated B cells and plasma cells. BACH1 was present in naïve B cells at approximately half the levels of BACH2. In activated B cells, BACH1 decreased compared to naïve B cells, whilst BACH2 increased. In plasma cells, BACH1 increased back to the same extent as in naïve B cells, whilst BACH2 was not detected. Their target genes, Prdm1 and Hmox1 , were highly induced in plasma cells. BACH1 was found to undergo degradation with lower concentrations of heme than BACH2. Therefore, BACH1 and BACH2 are similarly abundant in B cells but differ in heme sensitivity, potentially regulating gene expression differently depending on their heme responsiveness. [ABSTRACT FROM AUTHOR]

Ferroptosis is a cell death mechanism mediated by iron-dependent lipid peroxidation. Although ferroptosis has garnered attention as a cancer-suppressing mechanism, there are still limited markers available for identifying ferroptotic cells or assessing their sensitivity to ferroptosis. The study focused on biliverdin, an endogenous reducing substance in cells, and examined the dynamics of intracellular biliverdin during ferroptosis using a biliverdin-binding cyanobacteriochrome. It was found that intracellular biliverdin decreases during ferroptosis and that this decrease is specific to ferroptosis amongst different forms of cell death. Furthermore, the feasibility of predicting sensitivity to ferroptosis by measuring intracellular biliverdin was demonstrated using a ferroptosis model induced by the re-expression of the transcription factor BACH1. These findings provide further insight into ferroptosis research and are expected to contribute to the development of cancer therapies that exploit ferroptosis. [ABSTRACT FROM AUTHOR]

Ferroptosis is a form of regulated cell death characterized by iron-dependent phospholipid peroxidation and is closely related to various diseases. System Xc−, a cystine/glutamate antiporter, and glutathione peroxidase 4 (GPX4) are key molecules in ferroptosis. Erastin and RSL3, known as inhibitors of system Xc− and GPX4, respectively, are commonly used as ferroptosis inducers. Broad-Complex, Tramtrack and Bric a brac (BTB) and Cap'n'collar (CNC) homology 1 (BACH1), a heme-binding transcription repressor, promotes pro-ferroptotic signalling, and therefore, Bach1 -deficient cells are resistant to ferroptosis. Irikura et al. (Ferroptosis model system by the re-expression of BACH1. J. Biochem. 2023; 174 :239–52) constructed Bach1 -re-expressing immortalized mouse embryonic fibroblasts (iMEFs) from Bach1−/− mice, which induce ferroptosis simply through the depletion of 2-mercaptoethanol from the culture medium. Transcriptional repression by re-expressed BACH1 induces suppressed glutathione synthesis and increases labile iron. Furthermore, ferroptosis initiated by BACH1-re-expressing iMEFs is propagated to surrounding cells. Thus, the BACH1-re-expression system is a novel and powerful tool to investigate the cellular basis of ferroptosis. [ABSTRACT FROM AUTHOR]

Severe acute pancreatitis (SAP) is characterized by acute inflammation of the pancreas. The transcription factor BTB and CNC homology 1 (BACH1) has been implicated in various biological processes, including oxidative stress, apoptosis, and cell cycle regulation. However, its involvement in the pathogenesis of SAP remains relatively understudied. In the present work, our data demonstrated that BACH1 level was significantly increased in SAP patients, cellular, and animal models, while heat shock protein B1 (HSPB1) expression was weakened. Mechanistic assays validated that BACH1 acted as a transcriptional inhibitor of HSPB1. Moreover, HPDE6‐C7 cells were stimulated with cerulein (Cer) and LPS to mimic the pathological stages of SAP in vitro. Depletion of BACH1 remarkably improved cell survival and alleviated the oxidative stress, ferroptosis, and inflammatory responses in SAP cell models. However, these changes were dramatically reversed upon co‐inhibition of HSPB1. Animal findings confirmed that loss of BACH1 decreased pancreatic injury, inflammatory responses, and ferroptosis, but these effects were weakened by HSPB1 silence. Overall, these findings elucidate that the overexpression of BACH1 favors the ferroptosis and inflammation by transcriptionally inhibiting HSBP1, thereby exacerbating SAP progression. [ABSTRACT FROM AUTHOR]

Reperfusion after myocardial infarction (MI) can lead to myocardial ischemia/reperfusion (I/R) damage. The transcription factor (TF) broad-complex, tramtrack, and bric-a-brac (BTB) and cap'n'collar (CNC) homology 1 (BACH1) is implicated in the injury. However, the downstream mechanisms of BACH1 in affecting myocardial hypoxia/reoxygenation (H/R) damage are still fully understood. AC16 cells were stimulated with H/R conditions to model cardiomyocytes under H/R. mRNA analysis was performed by quantitative real-time PCR. Protein levels were gauged by immunoblot analysis. The effect of BACH1/cyclin-dependent kinase inhibitor 3 (CDKN3) on H/R-evoked injury was assessed by measuring cell viability via Cell Counting Kit-8 (CCK-8), apoptosis (flow cytometry and caspase 3 activity), ferroptosis via Fe2+, glutathione (GSH), reactive oxygen species (ROS) and malondialdehyde (MDA) markers and inflammation cytokines interleukin-1beta (IL-1β) and tumor necrosis factor alpha (TNF-α). The BACH1/CDKN3 relationship was examined by chromatin immunoprecipitation (ChIP) experiment and luciferase assay. BACH1 was increased in MI serum and H/R-stimulated AC16 cardiomyocytes. Functionally, disruption of BACH1 mitigated H/R-evoked in vitro apoptosis, ferroptosis and inflammation of AC16 cardiomyocytes. Mechanistically, BACH1 activated CDKN3 transcription and enhanced CDKN3 protein expression in AC16 cardiomyocytes. Our rescue experiments validated that BACH1 disruption attenuated H/R-evoked AC16 cardiomyocyte apoptosis, ferroptosis and inflammation by downregulating CDKN3. Additionally, BACH1 disruption could activate the adenosine monophosphate-activated protein kinase (AMPK) signaling by downregulating CDKN3 in H/R-stimulated AC16 cardiomyocytes. Our study demonstrates that BACH1 activates CDKN3 transcription to induce H/R-evoked damage of AC16 cardiomyocytes partially via AMPK signaling. [ABSTRACT FROM AUTHOR]

Objective Examine Bach1 protein expression in bone marrow biopsy specimens obtained from newly diagnosed multiple myeloma (NDMM) and iron deficiency anemia (IDA) patients. Conduct a thorough analysis to explore the potential connection between Bach1 and the onset as well as treatment response of NDMM.Methods This study investigated Bach1 expression in bone marrow biopsy tissues from NDMM and IDA patients. Immunohistochemical staining and Image-pro Plus software were utilized for quantitatively obtaining the expression level of Bach1 protein. Arrange Bach1 expression levels from high to low, and use its median expression level as the threshold. Samples with Bach1 expression level above the median are categorized as the high-expression group, while those below the median are categorized as the low-expression group. Under this grouping, a detailed discussion was conducted to explore relationship of the Bach1 expression level with the patients’ gender, ISS stage, and survival rate based on the Bortezomib (Btz) therapy.Results Our experiment indicates that the expression level of Bach1 in NDMM patients is significantly higher than in IDA patients. Furthermore, we discovered that patients in the high-expression group exhibit better prognosis compared to those in the low-expression group after Btz-treatment. Bioinformatics analysis further confirms this conclusion.Conclusion By categorizing Bach1 expression level as high and low, our study offers a unique perspective on understanding the relationship between Bach1 and NDMM.

Abstract Background Glucocorticoid-induced osteoporosis (GIOP) is the most common type of secondary osteoporosis. Recently, autophagy has been found to be related with the development of various diseases, including osteoporosis and osteoblast differentiation regulations. BTB and CNC homology 1 (BACH1) was a previously confirmed regulator for osteoblast differentiation, but whether it’s could involve in glucocorticoid-induced human bone mesenchymal stem cells (hBMSCs) differentiation and autophagy regulation remain not been elucidated. Methods hBMSCs were identified by flow cytometry method, and its differentiation ability were measured by ARS staining, oil O red, and Alcian blue staining assays. Gene and proteins were quantified via qRT-PCR and western blot assays, respectively. Autophagy activity was determined using immunofluorescence. ChIP and dual luciferase assay validated the molecular interactions. Results The data revealed that isolated hBMSCs exhibited positive of CD29/CD44 and negative CD45/CD34. Moreover, BACH1 was abated gradually during osteoblast differentiation of hBMSCs, while dexamethasone (Dex) treatment led to BACH1 upregulation. Loss of BACH1 improved osteoblast differentiation and activated autophagy activity in Dex-challenged hBMSCs. Autophagy-related proteins (ATG3, ATG4, ATG5, ATG7, ATG12) were repressed after Dex treatment, while ATG3, ATG7 and BECN1 could be elevated by BACH1 knockdown, especially ATG7. Moreover, BACH1 could interact ATG7 promoter region to inhibit its transcription. Co-inhibition of ATG7 greatly overturned the protective roles of BACH1 loss on osteoblast differentiation and autophagy in Dex-induced hBMSCs. Conclusion Taken together, our results demonstrated that silencing of BACH1 mitigated Dex-triggered osteogenic differentiation inhibition by transcriptionally activating ATG7-mediated autophagy, suggesting that BACH1 may be a therapeutic target for GIOP treatment.

Abstract Hyperproliferation of vascular smooth muscle cells (VSMCs) is a driver of hypertensive vascular remodeling. This study aimed to uncover the mechanism of BTB and CNC homology 1 (BACH1) and microRNAs (miRNAs) in VSMC growth and hypertensive vascular remodeling. With the help of TargetScan, miRWalk, miRDB, and miRTarBase online database, we identified that BACH1 might be targeted by miR-196a-5p, and overexpressed in VSMCs and aortic tissues from spontaneously hypertensive rats (SHRs). Gain- and loss-of-function experiments demonstrated that miR-196a-5p suppressed VSMC proliferation, oxidative stress and hypertensive vascular remodeling. Double luciferase reporter gene assay and functional verification showed that miR-196a-5p cracked down the transcription and translation of BACH1 in both Wistar Kyoto rats (WKYs) and SHRs. Silencing BACH1 mimicked the actions of miR-196a-5p overexpression on attenuating the proliferation and oxidative damage of VSMCs derived from SHRs. Importantly, miR-196a-5p overexpression and BACH1 knockdown cooperatively inhibited VSMC proliferation and oxidative stress in SHRs. Furthermore, miR-196a-5p, if knocked down in SHRs, aggravated hypertension, upregulated BACH1 and promoted VSMC proliferation, all contributing to vascular remodeling. Taken together, targeting miR-196a-5p to downregulate BACH1 may be a promising strategy for retarding VSMC proliferation and hypertensive vascular remodeling.

Background: Glucocorticoid-induced osteoporosis (GIOP) is the most common type of secondary osteoporosis. Recently, autophagy has been found to be related with the development of various diseases, including osteoporosis and osteoblast differentiation regulations. BTB and CNC homology 1 (BACH1) was a previously confirmed regulator for osteoblast differentiation, but whether it's could involve in glucocorticoid-induced human bone mesenchymal stem cells (hBMSCs) differentiation and autophagy regulation remain not been elucidated. Methods: hBMSCs were identified by flow cytometry method, and its differentiation ability were measured by ARS staining, oil O red, and Alcian blue staining assays. Gene and proteins were quantified via qRT-PCR and western blot assays, respectively. Autophagy activity was determined using immunofluorescence. ChIP and dual luciferase assay validated the molecular interactions. Results: The data revealed that isolated hBMSCs exhibited positive of CD29/CD44 and negative CD45/CD34. Moreover, BACH1 was abated gradually during osteoblast differentiation of hBMSCs, while dexamethasone (Dex) treatment led to BACH1 upregulation. Loss of BACH1 improved osteoblast differentiation and activated autophagy activity in Dex-challenged hBMSCs. Autophagy-related proteins (ATG3, ATG4, ATG5, ATG7, ATG12) were repressed after Dex treatment, while ATG3, ATG7 and BECN1 could be elevated by BACH1 knockdown, especially ATG7. Moreover, BACH1 could interact ATG7 promoter region to inhibit its transcription. Co-inhibition of ATG7 greatly overturned the protective roles of BACH1 loss on osteoblast differentiation and autophagy in Dex-induced hBMSCs. Conclusion: Taken together, our results demonstrated that silencing of BACH1 mitigated Dex-triggered osteogenic differentiation inhibition by transcriptionally activating ATG7-mediated autophagy, suggesting that BACH1 may be a therapeutic target for GIOP treatment. Highlight: • BACH1 was gradually reduced during osteogenic differentiation and induced by Dex. • Loss of BACH1 impaired Dex-induced osteogenic differentiation and autophagy inhibition. • BACH1 transcriptionally inhibited ATG7 expression. • The helpful effect of BACH1 silence on osteogenic differentiation and autophagy in Dex-induced BMSCs were reversed by ATG7 inhibition. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases constitute a global health issue and a major economic burden. They significantly impair both cognitive and motor functions, and their prevalence is expected to rise due to ageing societies and continuous population growth. Conventional therapies provide symptomatic relief, nevertheless, disease-modifying treatments that reduce or halt neuron death and malfunction are still largely unavailable. Amongst the common hallmarks of neurodegenerative diseases are protein aggregation, oxidative stress, neuroinflammation and mitochondrial dysfunction. Transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2) constitutes a central regulator of cellular defense mechanisms, including the regulation of antioxidant, antiinflammatory and mitochondrial pathways, making it a highly attractive therapeutic target for disease modification in neurodegenerative disorders. Here, we describe the role of NRF2 in the common hallmarks of neurodegeneration, review the current pharmacological interventions and their challenges in activating the NRF2 pathway, and present alternative therapeutic approaches for disease modification. [ABSTRACT FROM AUTHOR]

Hyperproliferation of vascular smooth muscle cells (VSMCs) is a driver of hypertensive vascular remodeling. This study aimed to uncover the mechanism of BTB and CNC homology 1 (BACH1) and microRNAs (miRNAs) in VSMC growth and hypertensive vascular remodeling. With the help of TargetScan, miRWalk, miRDB, and miRTarBase online database, we identified that BACH1 might be targeted by miR-196a-5p, and overexpressed in VSMCs and aortic tissues from spontaneously hypertensive rats (SHRs). Gain- and loss-of-function experiments demonstrated that miR-196a-5p suppressed VSMC proliferation, oxidative stress and hypertensive vascular remodeling. Double luciferase reporter gene assay and functional verification showed that miR-196a-5p cracked down the transcription and translation of BACH1 in both Wistar Kyoto rats (WKYs) and SHRs. Silencing BACH1 mimicked the actions of miR-196a-5p overexpression on attenuating the proliferation and oxidative damage of VSMCs derived from SHRs. Importantly, miR-196a-5p overexpression and BACH1 knockdown cooperatively inhibited VSMC proliferation and oxidative stress in SHRs. Furthermore, miR-196a-5p, if knocked down in SHRs, aggravated hypertension, upregulated BACH1 and promoted VSMC proliferation, all contributing to vascular remodeling. Taken together, targeting miR-196a-5p to downregulate BACH1 may be a promising strategy for retarding VSMC proliferation and hypertensive vascular remodeling. [ABSTRACT FROM AUTHOR]

Doxorubicin (DOX) is one of the most frequently used chemotherapeutic drugs belonging to the class of anthracyclines. However, the cardiotoxic effects of anthracyclines limit their clinical use. Recent studies have suggested that ferroptosis is the main underlying pathogenetic mechanism of DOX-induced cardiomyopathy (DIC). BTB-and-CNC homology 1 (Bach1) acts as a key role in the regulation of ferroptosis. However, the mechanistic role of Bach1 in DIC remains unclear. Therefore, this study aimed to investigate the underlying mechanistic role of Bach1 in DOX-induced cardiotoxicity using the DIC mice in vivo (DOX at cumulative dose of 20 mg/kg) and the DOX-treated H9c2 cardiomyocytes in vitro (1 μM). Our results show a marked upregulation in the expression of Bach1 in the cardiac tissues of the DOX-treated mice and the DOX-treated cardiomyocytes. However, Bach1−/− mice exhibited reduced lipid peroxidation and less severe cardiomyopathy after DOX treatment. Bach1 knockdown protected against DOX-induced ferroptosis in both in vivo and in vitro models. Ferrostatin-1 (Fer-1), a potent inhibitor of ferroptosis, significantly alleviated DOX-induced cardiac damage. However, the cardioprotective effects of Bach1 knockdown were reversed by pre-treatment with Zinc Protoporphyrin (ZnPP), a selective inhibitor of heme oxygenase-1(HO-1). Taken together, these findings demonstrated that Bach1 promoted oxidative stress and ferroptosis through suppressing the expression of HO-1. Therefore, Bach1 may present as a promising new therapeutic target for the prevention and early intervention of DOX-induced cardiotoxicity. Highlight: Ferroptosis is responsible for doxorubicin-induced cardiotoxicity. Bach1 expression is prominently increased by doxorubicin. Bach1 knockdown alleviates doxorubicin-induced cardiotoxicity. Bach1 promotes ferroptosis of cardiomyocytes through downregulation of HO-1. [ABSTRACT FROM AUTHOR]

To investigate the potential role and molecular mechanism of circ_0005015 in GBM progression. Circ_0005015, microRNA-382-5p (miR-382-5p), and BTB domain and CNC homolog 1 (BACH1) levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation was determined by MTT, colony formation, and EdU assays. Cell apoptosis was analyzed using flow cytometry. Cell migration and invasion were assessed using wound healing and transwell assays. Glucose accumulation and lactate levels were examined by the corresponding kit. RNA pull-down and dual-luciferase reporter assays were performed to confirm the interaction between miR-382-5p and circ_0005015 or BACH1. Protein levels of MMP9, PCNA, and BACH1 were examined using western blot assay. Role of circ_0005015 on tumor growth in vivo was analyzed using a xenograft tumor model. Circ_0005015 content was up-regulated in GBM patients and cells, its knockdown restrained GBM cell proliferation, migration, invasion, glycolysis, and triggered apoptosis. Mechanistically, we found that circ_0005015 could directly interact with miR-382-5p and serve as a miRNA sponge to regulate BACH1 expression. In addition, circ_0005015 knockdown might repress tumor growth in vivo. Circ_0005015 boosted GBM progression via binding to miR-382-5p to up-regulate BACH1, which may offer new effective targets for GBM treatment. [ABSTRACT FROM AUTHOR]

BTB and CNC homology 1 (BACH1) represses the expression of genes involved in the metabolism of iron, heme and reactive oxygen species. While BACH1 is rapidly degraded when it is bound to heme, it remains unclear how BACH1 degradation is regulated under other conditions. We found that FBXO22, a ubiquitin ligase previously reported to promote BACH1 degradation, polyubiquitinated BACH1 only in the presence of heme in a highly purified reconstitution assay. In parallel to this regulatory mechanism, TANK binding kinase 1 (TBK1), a protein kinase that activates innate immune response and regulates iron metabolism via ferritinophagy, was found to promote BACH1 degradation when overexpressed in 293T cells. While TBK1 phosphorylated BACH1 at multiple serine and threonine residues, BACH1 degradation was observed with not only the wild-type TBK1 but also catalytically impaired TBK1. The BACH1 degradation in response to catalytically impaired TBK1 was not dependent on FBXO22 but involved both autophagy-lysosome and ubiquitin-proteasome pathways judging from its suppression by using inhibitors of lysosome and proteasome. Chemical inhibition of TBK1 in hepatoma Hepa1 cells showed that TBK1 was not required for the heme-induced BACH1 degradation. Its inhibition in Namalwa B lymphoma cells increased endogenous BACH1 protein. These results suggest that TBK1 promotes BACH1 degradation in parallel to the FBXO22- and heme-dependent pathway, placing BACH1 as a downstream effector of TBK1 in iron metabolism or innate immune response. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases constitute a global health issue and a major economic burden. They significantly impair both cognitive and motor functions, and their prevalence is expected to rise due to ageing societies and continuous population growth. Conventional therapies provide symptomatic relief, nevertheless, disease-modifying treatments that reduce or halt neuron death and malfunction are still largely unavailable. Amongst the common hallmarks of neurodegenerative diseases are protein aggregation, oxidative stress, neuroinflammation and mitochondrial dysfunction. Transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2) constitutes a central regulator of cellular defense mechanisms, including the regulation of antioxidant, anti-inflammatory and mitochondrial pathways, making it a highly attractive therapeutic target for disease modification in neurodegenerative disorders. Here, we describe the role of NRF2 in the common hallmarks of neurodegeneration, review the current pharmacological interventions and their challenges in activating the NRF2 pathway, and present alternative therapeutic approaches for disease modification.

Abstract Background Damage in the ischemic core and penumbra after stroke affects patient prognosis. Microglia immediately respond to ischemic insult and initiate immune inflammation, playing an important role in the cellular injury after stroke. However, the microglial heterogeneity and the mechanisms involved remain unclear. Methods We first performed single-cell RNA-sequencing (scRNA-seq) and spatial transcriptomics (ST) on middle cerebral artery occlusion (MCAO) mice from three time points to determine stroke-associated microglial subclusters and their spatial distributions. Furthermore, the expression of microglial subcluster-specific marker genes and the localization of different microglial subclusters were verified on MCAO mice through RNAscope and immunofluorescence. Gene set variation analysis (GSVA) was performed to reveal functional characteristics of microglia sub-clusters. Additionally, ingenuity pathway analysis (IPA) was used to explore upstream regulators of microglial subclusters, which was confirmed by immunofluorescence, RT-qPCR, shRNA-mediated knockdown, and targeted metabolomics. Finally, the infarct size, neurological deficits, and neuronal apoptosis were evaluated in MCAO mice after manipulation of specific microglial subcluster. Results We discovered stroke-associated microglial subclusters in the brains of MCAO mice. We also identified novel marker genes of these microglial subclusters and defined these cells as ischemic core-associated (ICAM) and ischemic penumbra-associated (IPAM) microglia, according to their spatial distribution. ICAM, induced by damage-associated molecular patterns, are probably fueled by glycolysis, and exhibit increased pro-inflammatory cytokines and chemokines production. BACH1 is a key transcription factor driving ICAM generation. In contrast, glucocorticoids, which are enriched in the penumbra, likely trigger IPAM formation, which are presumably powered by the citrate cycle and oxidative phosphorylation and are characterized by moderate pro-inflammatory responses, inflammation-alleviating metabolic features, and myelinotrophic properties. Conclusions ICAM could induce excessive neuroinflammation, aggravating brain injury, whereas IPAM probably exhibit neuroprotective features, which could be essential for the homeostasis and survival of cells in the penumbra. Our findings provide a biological basis for targeting specific microglial subclusters as a potential therapeutic strategy for ischemic stroke.

BackgroundIn 2015, herpes simplex virus 1 (HSV-1)-derived talimogene laherparepvec (T-VEC) was the first oncolytic virus approved by the US Food and Drug Administration as a therapeutic agent for cancer treatment. However, its antitumor application is limited to local treatment of melanoma, and there is a lack of understanding of the mechanisms underlying the regulation of HSV-1 replication in cancer cells and the associated antitumor immunity. We hypothesized that increasing the replication capacity of HSV-1 in tumor cells would enhance the antitumor effect of this virus.MethodsWe systematically identified IFN-stimulated genes induced by HSV-1 by performing functional screens and clarified the mechanism by which BACH1 acts against HSV-1. Then, we tested the effect of BACH1 deficiency on immunogenic cell death induced by HSV-1. Furthermore, we investigated the antitumor effect of BACH1 deficiency on HSV-1 in MCA205 and B16 murine tumor models.ResultsWe identified eight IFN-stimulated genes (ISGs) controlling HSV-1 replication, among which BTB and CNC homology 1 (BACH1) suppressed HSV-1 replication by inhibiting the transcription of ICP4, ICP27, and UL39. Loss of Bach1 function not only increased HSV-1 proliferation but also promoted HSV-1-induced cell apoptosis, HMGB1 secretion, and calreticulin exposure in tumor cells. More importantly, hemin, an FDA-approved drug known to downregulate BACH1, significantly enhanced HSV-1-mediated antitumor activity with increased T lymphocyte infiltration at the tumor site.ConclusionsOur studies uncovered a novel antiviral activity of BACH1 and provided a new strategy for improving the clinical efficiency of the oncolytic virus HSV-1.

The transcription factor Nrf2 is the master regulator of cellular stress response, facilitating the expression of cytoprotective genes, including those responsible for drug detoxification, immunomodulation, and iron metabolism. FDA‐approved Nrf2 activators, Tecfidera and Skyclarys for patients with multiple sclerosis and Friedreich's ataxia, respectively, are non‐specific alkylating agents exerting side effects. Nrf2 is under feedback regulation through its target gene, transcriptional repressor Bach1. Specifically, in Parkinson's disease and other neurodegenerative diseases with Bach1 dysregulation, excessive Bach1 accumulation interferes with Nrf2 activation. Bach1 is a heme sensor protein, which, upon heme binding, is targeted for proteasomal degradation, relieving the repression of Nrf2 target genes. Ideally, a combination of Nrf2 stabilization and Bach1 inhibition is necessary to achieve the full therapeutic benefits of Nrf2 activation. Here, we discuss recent advances and future perspectives in developing small molecule inhibitors of Bach1, highlighting the significance of the Bach1/Nrf2 signaling pathway as a promising neurotherapeutic strategy. [ABSTRACT FROM AUTHOR]

Background: Damage in the ischemic core and penumbra after stroke affects patient prognosis. Microglia immediately respond to ischemic insult and initiate immune inflammation, playing an important role in the cellular injury after stroke. However, the microglial heterogeneity and the mechanisms involved remain unclear. Methods: We first performed single-cell RNA-sequencing (scRNA-seq) and spatial transcriptomics (ST) on middle cerebral artery occlusion (MCAO) mice from three time points to determine stroke-associated microglial subclusters and their spatial distributions. Furthermore, the expression of microglial subcluster-specific marker genes and the localization of different microglial subclusters were verified on MCAO mice through RNAscope and immunofluorescence. Gene set variation analysis (GSVA) was performed to reveal functional characteristics of microglia sub-clusters. Additionally, ingenuity pathway analysis (IPA) was used to explore upstream regulators of microglial subclusters, which was confirmed by immunofluorescence, RT-qPCR, shRNA-mediated knockdown, and targeted metabolomics. Finally, the infarct size, neurological deficits, and neuronal apoptosis were evaluated in MCAO mice after manipulation of specific microglial subcluster. Results: We discovered stroke-associated microglial subclusters in the brains of MCAO mice. We also identified novel marker genes of these microglial subclusters and defined these cells as ischemic core-associated (ICAM) and ischemic penumbra-associated (IPAM) microglia, according to their spatial distribution. ICAM, induced by damage-associated molecular patterns, are probably fueled by glycolysis, and exhibit increased pro-inflammatory cytokines and chemokines production. BACH1 is a key transcription factor driving ICAM generation. In contrast, glucocorticoids, which are enriched in the penumbra, likely trigger IPAM formation, which are presumably powered by the citrate cycle and oxidative phosphorylation and are characterized by moderate pro-inflammatory responses, inflammation-alleviating metabolic features, and myelinotrophic properties. Conclusions: ICAM could induce excessive neuroinflammation, aggravating brain injury, whereas IPAM probably exhibit neuroprotective features, which could be essential for the homeostasis and survival of cells in the penumbra. Our findings provide a biological basis for targeting specific microglial subclusters as a potential therapeutic strategy for ischemic stroke. [ABSTRACT FROM AUTHOR]

Periodontal bone regeneration is a major challenge in the treatment of periodontitis. However, the regenerative vitality of periodontal ligament cells (PDLCs) declines in the environment of periodontitis and accompanying oxidative stress. This study aimed to investigate the functional mechanisms of Bach1, a transcriptional suppressor involved in oxidative stress response, and its regulation of PDLC osteogenesis under inflammatory conditions. We observed a significant elevation in Bach1 expression in periodontal tissues with periodontitis and PDLCs under inflammatory conditions. Knockdown of Bach1 alleviated the inflammation‐induced oxidative stress level and partly offset the inhibitory effect of inflammatory conditions on osteogenesis, as well as the expression of osteogenic genes BMP6, OPG and RUNX2. Similarly, knockdown of Bach1 protects PDLCs from inflammatory damage to periodontal bone regeneration in vivo. Furthermore, we found that Bach1 could bind to the histone methyltransferase EZH2, and the binding increased under inflammatory conditions. Bach1 enhanced the ability of EZH2 to catalyse H3K27me3 on the promoter region of RUNX2 and BMP6, thus repressing the expression of osteoblastic genes. In conclusion, our study revealed that knockdown of Bach1 effectively rescued the osteogenesis and oxidative stress of PDLCs with inflammation. Bach1 could be a promising target for enhancing periodontal tissue regeneration under periodontitis conditions. [ABSTRACT FROM AUTHOR]

Objectives: Nrf2/BACH1/HO-1 proteins have been implicated in the development and progression of tumors. However, their clinical relevance in breast cancer remains unclear and understudied. This study evaluated Nrf2/BACH1/HO-1 protein expression and its relationship with age, tumor grade, tumor stage, TNM, ER, PR, HER2, and histologic type. Methods: 114 female breast cancer and 30 noncancerous tissues were evaluated for Nrf2/BACH1/HO-1 protein expression using immunohistochemistry and Western blot. The relationships between the expression and clinicopathologic factors were assessed using the χ2 test. Results: 74% of the cancerous samples had high Nrf2 protein expression, and 26% of them had low Nrf2 protein expression. Regarding the non-cancer samples, 43% had high Nrf2 protein expression and 57% had low Nrf2 protein expression (p < 0.002). 39% of the cancerous samples had high BACH1 protein expression, and 61% had low BACH1 protein expression. For the non-cancer samples, 80% had high BACH1 protein expression and 20% had low BACH1 protein expression (p < 0.031). 67% of the cancerous samples had high HO-1 protein expression, and 33% had low HO-1 protein expression. However, for the non-cancer samples, 17% of them had high HO-1 protein expression and 83% had low HO-1 protein expression (p < 0.001). The expression of Nrf2 and HO-1 significantly correlated with tumor grade, while BACH1 was significantly associated with tumor stage (p < 0.05). Conclusion: Nrf2, BACH1, and HO-1 could be explored as a biomarker for cancer stage, progression, and prognosis. [ABSTRACT FROM AUTHOR]

Ferroptosis is a regulated cell death induced by iron-dependent lipid peroxidation. The heme-responsive transcription factor BTB and CNC homology 1 (BACH1) promotes ferroptosis by repressing the transcription of genes involved in glutathione (GSH) synthesis and intracellular labile iron metabolism, which are key regulatory pathways in ferroptosis. We found that BACH1 re-expression in Bach1 −/− immortalized mouse embryonic fibroblasts (iMEFs) can induce ferroptosis upon 2-mercaptoethanol removal, without any ferroptosis inducers. In these iMEFs, GSH synthesis was reduced, and intracellular labile iron levels were increased upon BACH1 re-expression. We used this system to investigate whether the major ferroptosis regulators glutathione peroxidase 4 (Gpx4) and apoptosis-inducing factor mitochondria-associated 2 (Aifm2), the gene for ferroptosis suppressor protein 1, are target genes of BACH1. Neither Gpx4 nor Aifm2 was regulated by BACH1 in the iMEFs. However, we found that BACH1 represses AIFM2 transcription in human pancreatic cancer cells. These results suggest that the ferroptosis regulators targeted by BACH1 may vary across different cell types and animal species. Furthermore, we confirmed that the ferroptosis induced by BACH1 re-expression exhibited a propagating effect. BACH1 re-expression represents a new strategy for inducing ferroptosis after GPX4 or system Xc− suppression and is expected to contribute to future ferroptosis research. [ABSTRACT FROM AUTHOR]

BACH1 plays an important role in promoting cancer. This study aims to further verify the relationship between the expression level of BACH1 in lung adenocarcinoma prognosis, as well as the influence of BACH1 expression on lung adenocarcinoma and the potential mechanism. The expression level of BACH1 in lung adenocarcinoma and its relationship with prognosis was evaluated by lung adenocarcinoma tissue microarray analysis combined with bioinformatics approaches. Gene knockdown and overexpression were used to investigate the functions and molecular mechanisms of BACH1 in lung adenocarcinoma cells. The regulatory downstream pathways and target genes of BACH1 in lung adenocarcinoma cells were explored by bioinformatics and RNA sequencing data analysis, real‐time PCR, western blot analysis, and cell immunofluorescence and cell adhesion assays. Chromatin immunoprecipitation and dual‐luciferase reporter assays were carried out to verify the target gene binding site. In the present study, BACH1 is abnormally highly expressed in lung adenocarcinoma tissues, and high BACH1 expression is negatively correlated with patient prognosis. BACH1 promotes the migration and invasion of lung adenocarcinoma cells. Mechanistically, BACH1 directly binds to the upstream sequence of the ITGA2 promoter to promote ITGA2 expression, and the BACH1‐ITGA2 axis is involved in cytoskeletal regulation in lung adenocarcinoma cells by activating the FAK‐RAC1‐PAK signaling pathway. Our results indicated that BACH1 positively regulates the expression of ITGA2 through a transcriptional mechanism, thereby activating the FAK‐RAC1‐PAK signaling pathway to participate in the formation of the cytoskeleton in tumor cells and then promoting the migration and invasion of tumor cells. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNA) have been reported to be involved in the progression of cerebral infarction. The purpose of this study was to reveal the role and potential molecular mechanism of circZfp609 (mmu_circ_0001797) in cerebral infarction. Methods: C57BL/6J mice was used to construct middle cerebral artery occlusion (MCAO) mice model, and primary mouse astrocytes were treated with oxygen-glucose deprivation/reperfusion (OGD/R) process. The circZfp609, microRNA (miR)-145a-5p and BTB and CNC homology 1 (BACH1) expression levels were detected by quantitative real-time PCR. Cell proliferation and apoptosis were assessed by cell counting kit 8 assay, EdU assay and flow cytometry. Western blot analysis was used to measure protein levels, and ELISA assay was utilized to detect the levels of inflammation factors. Lactate dehydrogenase (LDH) level was measured by LDH Assay Kit. Dual-luciferase reporter assay, RIP assay and RNA pull-down assay were used to evaluate RNA interaction. Results: CircZfp609 was upregulated in MCAO mice and OGD/R-induced astrocytes. Knockdown of circZfp609 promoted cell proliferation, while suppressed apoptosis and inflammation in OGD/R-induced astrocytes. CircZfp609 served as a sponge for miR-145a-5p, and miR-145a-5p inhibitor reversed the regulation of circZfp609 knockdown on OGD/R-induced astrocyte injury. BACH1 was a target of miR-145a-5p, and its overexpression abolished the inhibition effect of miR-145a-5p on OGD/R-induced astrocyte injury. Besides, circZfp609 downregulation also relieved the brain injury of MCAO mice through miR-145a-5p/BACH1 axis. Conclusion: Our data showed that circZfp609 might promote cerebral infarction by regulating the miR-145a-5p/BACH1 pathway. [ABSTRACT FROM AUTHOR]

The deubiquitinating enzyme USP14 has been established as a crucial regulator in various diseases, including tumors, neurodegenerative diseases, and metabolic diseases, through its ability to stabilize its substrate proteins. Our group has utilized proteomic techniques to identify new potential substrate proteins for USP14, however, the underlying signaling pathways regulated by USP14 remain largely unknown. Here, we demonstrate the key role of USP14 in both heme metabolism and tumor invasion by stabilizing the protein BACH1. The cellular oxidative stress response factor NRF2 regulates antioxidant protein expression through binding to the antioxidant response element (ARE). BACH1 can compete with NRF2 for ARE binding, leading to the inhibition of the expression of antioxidant genes, including HMOX-1. Activated NRF2 also inhibits the degradation of BACH1, promoting cancer cell invasion and metastasis. Our findings showed a positive correlation between USP14 expression and NRF2 expression in various cancer tissues from the TCGA database and normal tissues from the GTEx database. Furthermore, activated NRF2 was found to increase USP14 expression in ovarian cancer (OV) cells. The overexpression of USP14 was observed to inhibit HMOX1 expression, while USP14 knockdown had the opposite effect, suggesting a role for USP14 in regulating heme metabolism. The depletion of BACH1 or inhibition of heme oxygenase 1 (coded by HMOX-1) was also found to significantly impair USP14-dependent OV cell invasion. In conclusion, our results highlight the importance of the NRF2-USP14-BACH1 axis in regulating OV cell invasion and heme metabolism, providing evidence for its potential as a therapeutic target in related diseases. • USP14 binds directly to BACH1 protein in ovarian cancer cells. • USP14 regulates protein half-life and ubiquitination modifications of BACH1 in ovarian cancer cells. • Activated NRF2 promotes the expression of USP14, and USP14 can regulate heme metabolism. • USP14 regulates ovarian cancer cell invasion dependent on BACH1 protein. [ABSTRACT FROM AUTHOR]

It has been confirmed that BTB domain and CNC homologue 1 (BACH1) are involved in ferroptosis‐related diseases. However, the function of BACH1 in cerebral ischemia–reperfusion injury (CIRI)‐induced ferroptosis remains to be largely unrevealed. First, analysis of differentially expressed genes in CIRI based on the GEO dataset GSE119121 revealed that BACH1 was upregulated in CIRI. BACH1 level was prominently increased in middle cerebral artery occlusion (MCAO)/reperfusion model and oxygen–glucose deprivation/reoxygenation cell model. Further, knock‐down of BACH1 markedly reduced iron ion concentration, ROS production, 4‐HNE and lipid peroxidation levels and facilitated GSH content, cell viability and protein levels of GPX4 and SLC7A11, while an pcDNA‐KDM4C or pcDNA‐COX2 combined with BACH1 siRNA could not enhance this effect. Mechanistically, BACH1 bound on the KDM4C promoter to transcriptionally activate its expression. Besides, KDM4C could occupy the promoter locus of the COX2 gene, promoting the COX2 expression by eliminating H3K9me3. Overexpression of KDM4C or COX2 overturned the effects of BACH1 inhibition. In vivo findings displayed that brain infraction, pathological damage and neuronal loss rate in MCAO mice were conspicuously decreased after BACH1 knock‐down. This study reveals that BACH1 encourages ferroptosis in neuroblastoma cells and CIRI mouse brain tissues by activating KDM4C‐mediated COX2 demethylation. [ABSTRACT FROM AUTHOR]

Aims BACH1 is up-regulated in hypertrophic hearts, but its function in cardiac hypertrophy remains largely unknown. This research investigates the function and mechanisms of BACH1 in the regulation of cardiac hypertrophy. Methods and results Male cardiac-specific BACH1 knockout mice or cardiac-specific BACH1 transgenic (BACH1-Tg) mice and their respective wild-type littermates developed cardiac hypertrophy induced by angiotensin II (Ang II) or transverse aortic constriction (TAC). Cardiac-specific BACH1 knockout in mice protected the hearts against Ang II- and TAC-induced cardiac hypertrophy and fibrosis, and preserved cardiac function. Conversely, cardiac-specific BACH1 overexpression markedly exaggerated cardiac hypertrophy and fibrosis and reduced cardiac function in mice with Ang II- and TAC-induced hypertrophy. Mechanistically, BACH1 silencing attenuated Ang II- and norepinephrine-stimulated calcium/calmodulin-dependent protein kinase II (CaMKII) signalling, the expression of hypertrophic genes, and hypertrophic growth of cardiomyocytes. Ang II stimulation promoted the nuclear localization of BACH1, facilitated the recruitment of BACH1 to the Ang II type 1 receptor (AT1R) gene promoter, and then increased the expression of AT1R. Inhibition of BACH1 attenuated Ang II-stimulated AT1R expression, cytosolic Ca2+ levels, and CaMKII activation in cardiomyocytes, whereas overexpression of BACH1 led to the opposite effects. The increased expression of hypertrophic genes induced by BACH1 overexpression upon Ang II stimulation was suppressed by CaMKII inhibitor KN93. The AT1R antagonist, losartan, significantly attenuated BACH1-mediated CaMKII activation and cardiomyocyte hypertrophy under Ang II stimulation in vitro. Similarly, Ang II-induced myocardial pathological hypertrophy, cardiac fibrosis, and dysfunction in BACH1-Tg mice were blunted by treatment with losartan. Conclusion This study elucidates a novel important role of BACH1 in pathological cardiac hypertrophy by regulating the AT1R expression and the Ca2+/CaMKII pathway, and highlights potential therapeutic target in pathological cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

Steatosis, or ectopic lipid deposition, is the fundamental pathophysiology of non-alcoholic steatohepatitis and chronic kidney disease. Steatosis in the renal tubule causes endoplasmic reticulum (ER) stress, leading to kidney injury. Thus, ER stress could be a therapeutic target in steatonephropathy. Five-aminolevulinic acid (5-ALA) is a natural product that induces heme oxygenase (HO)-1, which acts as an antioxidant. This study aimed to investigate the therapeutic potential of 5-ALA in lipotoxicity-induced ER stress in human primary renal proximal tubule epithelial cells. Cells were stimulated with palmitic acid (PA) to induce ER stress. Cellular apoptotic signals and expression of genes involved in the ER stress cascade and heme biosynthesis pathway were analyzed. The expression of glucose-regulated protein 78 (GRP78), a master regulator of ER stress, increased significantly, followed by increased cellular apoptosis. Administration of 5-ALA induced a remarkable increase in HO-1 expression, thus ameliorating PA-induced GRP78 expression and apoptotic signals. BTB and CNC homology 1 (BACH1), a transcriptional repressor of HO-1, was significantly downregulated by 5-ALA treatment. HO-1 induction attenuates PA-induced renal tubular injury by suppressing ER stress. This study demonstrates the therapeutic potential of 5-ALA against lipotoxicity through redox pathway. [ABSTRACT FROM AUTHOR]

Hyperglycaemia‐mediated endothelial‐to‐mesenchymal transition (EndMT) is involved in the occurrence and progression of cardiovascular complications in diabetic patients. Previous studies reported that AKT serine/threonine kinase 3 (AKT3) and Bric‐a‐brac/Tramtrack/Broad (BTB) and cap'n'collar (CNC) homology 1 (bach1) participates in endothelial injury and epithelial‐to‐mesenchymal transition. In the present study, we proposed that bach1 regulates AKT3 transcription, thus involved in hyperglycaemia‐mediated EndMT in vascular endothelium. Our results indicated that hyperglycaemia/high glucose increased AKT3 expression and induced EndMT in aorta of diabetic rats and hyperglycaemic human umbilical vein endothelial cells (HUVECs). Moreover, inhibition of AKT3 expression reversed high glucose‐mediated EndMT in HUVECs. Further, hyperglycaemia/high glucose augmented bach1 expression in aorta of diabetic rats and hyperglycaemic HUVECs. Furthermore, si‐bach1 countered high glucose‐induced AKT3 expression and EndMT in HUVECs. In addition, the effect of bach1 overexpression is similar to that of high glucose treatment, which was reversed by si‐AKT3. ChIP assays found bach1 enriched in the promoter region of AKT3. Bach1 overexpression augmented AKT3 promoter activity, which lost after specific binding site mutation. Bach1 was involved in hyperglycaemia‐induced EndMT via modulation of AKT3 transcription. [ABSTRACT FROM AUTHOR]

Background: Intervertebral disc degeneration (IDD) is a primary health problem worldwide that involves oxidative stress, ferroptosis, and lipid metabolism. However, the underlying mechanism remains unclear. We investigated whether the transcription factor BTB and CNC homology 1 (BACH1) affected IDD progression by regulating HMOX1/GPX4‐mediated ferroptosis and lipid metabolism in nucleus pulposus cells (NPCs). Methods: A rat IDD model was created to detect BACH1 expression in intervertebral disc tissues. Next, rat NPCs were isolated and treated with tert‐butyl hydroperoxide (TBHP). BACH1, HMOX1, and GPX4 were knocked down, and oxidative stress and ferroptosis‐related marker levels were examined. The binding of BACH1 to HMOX1 and of BACH1 to GPX4 was verified using chromatin immunoprecipitation (ChIP). Finally, untargeted lipid metabolism analysis was performed. Results: An IDD model was successfully created, and BACH1 activity was found to be enhanced in the rat IDD tissues. BACH1 inhibited TBHP‐induced oxidative stress and oxidative stress‐induced ferroptosis in NPCs. Simultaneously, ChIP verified that BACH1 protein bound to HMOX1 and targeted the HMOX1 transcription inhibition to affect oxidative stress in NPCs. ChIP also verified that BACH1 bound to GPX4 and targeted the GPX4 inhibition to affect ferroptosis in NPCs. Finally, BACH1 inhibition in vivo improved IDD and affected lipid metabolism. Conclusions: The transcription factor BACH1 promoted IDD by regulating HMOX1/GPX4 to mediate oxidative stress, ferroptosis, and lipid metabolism in NPCs. [ABSTRACT FROM AUTHOR]

The malfunction of vascular smooth muscle cells (VSMCs) is an initiating factor in the pathogenesis of pathological vascular remodeling, including hypertension-related vascular lesions. MicroRNAs (miRNAs) have been implicated in the pathogenesis of VSMC proliferation and migration in numerous cases of cardiovascular remodeling. The evidence for the regulatory role of miR-155-5p in the development of the cardiovascular system has been emerging. However, it was previously unclear whether miR-155-5p participated in the migration of VSMCs under hypertensive conditions. Thus, we aimed to define the exact role and action of miR-155-5p in VSMC migration by hypertension. Here, we detected that the level of miR-155-5p was lower in primary VSMCs from spontaneously hypertensive rats (SHRs). Its overexpression attenuated, while its depletion accelerated, the migration and oxidative damage of VSMCs from SHRs. Our dual-luciferase reporter assay showed that miRNA-155-5p directly targeted the 3′-untranslated region (3′-UTR) of BTB and CNC homology 1 (BACH1). The miR-155-5p mimic inhibited BACH1 upregulation in SHR VSMCs. By contrast, the deletion of miR-155-5p further elevated the upregulation of BACH1 in SHR-derived VSMCs. Importantly, the overexpression of miR-155-5p and knockdown of BACH1 had synergistic effects on the inhibition of VSMCs in hypertension. Collectively, miR-155-5p attenuates VSMC migration and ameliorates vascular remodeling in SHRs, via suppressing BACH1 expression. [ABSTRACT FROM AUTHOR]

Abstract Background The preservation of biological and physiological vitality as well as the formation of dentin are among the main tasks of human dental pulp for a life time. Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) exhibits the capacity of dental pulp regeneration and dentin complex rebuilding. Exploration of the mechanisms regulating differentiation and proliferation of hDPSCs may help to investigate potential clinical applications. BTB and CNC homology 1 (BACH1) is a transcription repressor engaged in the regulation of multiple cellular functions. This study aimed to investigate the effects of BACH1 on the proliferation and odontoblastic differentiation of hDPSCs in vitro. Methods hDPSCs and pulpal tissues were obtained from extracted human premolars or third molars. The distribution of BACH1 was detected by immunohistochemistry. The mRNA and protein expression of BACH1 were examined by qRT-PCR and Western blot analysis. BACH1 expression was regulated by stable lentivirus-mediated transfection. Cell proliferation and cell cycle were assessed by cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay and flow cytometry. The expression of mineralization markers, alkaline phosphatase (ALP) activity and alizarin red S staining were conducted to assess the odontoblastic differentiation ability. Results BACH1 expression was stronger in the odontoblast layer than in the cell rich zone. The total and nuclear protein level of BACH1 during odontoblastic differentiation was downregulated initially and then upregulated gradually. Knockdown of BACH1 greatly inhibited cell proliferation, arrested cell cycle, upregulated the heme oxygenase-1 (HO-1) expression and attenuated ALP activity, decreased calcium deposits and downregulated the expression of mineralization markers. Treatment of Tin-protoporphyrin IX, an HO-1 inhibitor, failed to rescue the impaired odonto/osteogenic differentiation capacity. Overexpression of BACH1 increased cell proliferation, ALP activity and the expression of mineralization markers. Conclusions Our findings suggest that BACH1 is an important regulator of the proliferation and odontoblastic differentiation of hDPSCs in vitro. Manipulation of BACH1 expression may provide an opportunity to promote the regenerative capacity of hDPSCs.

The poor prognosis of triple negative breast cancer (TNBC) results from a lack of approved targeted therapies coupled with aggressive proliferation and metastasis, which is associated with high recurrence and short overall survival. Here we developed a strategy by employing tumor-targeted self-assembled nanoparticles to coordinately regulate BACH1 (BTB domain and CNC homology 1) and mitochondrial metabolism. The BACH1 inhibitor hemin and mitochondria function inhibitor berberine derivative (BD) were used to prepare nanoparticles (BH NPs) followed by the modification of chondroitin sulfate (CS) on the surface of BH NPs to achieve tumor targeting (CS/BH NPs). CS/BH NPs were found to be able to inhibit tumor migration and invasion by significantly decreasing the amounts of tumor cell metabolites, glycolysis and metastasis-associated proteins, which were related to the inhibition of BACH1 function. Meanwhile, decreased mitochondrial membrane potential, activated caspase 3/9 and increased ROS production demonstrated coordinated regulation of BACH1 and mitochondrial metabolism. In a xenograft mice model of breast cancer, CS/BH NPs significantly inhibited tumor growth and metastasis due to the synergetic effect of hemin and BD without showing obvious toxicities for major organs. In sum, the results of efficacy and safety experiments suggest potential clinical significance of the prepared self-assembled CS/BH nanoparticles for the treatment of TNBC.

BTB and CNC homologous (BACH) proteins, including BACH1 and BACH2, are transcription factors that are widely expressed in human tissues. BACH proteins form heterodimers with small musculoaponeurotic fibrosarcoma (MAF) proteins to suppress the transcription of target genes. Furthermore, BACH1 promotes the transcription of target genes. BACH proteins regulate physiological processes, such as the differentiation of B cells and T cells, mitochondrial function, and heme homeostasis as well as pathogenesis related to inflammation, oxidative-stress damage caused by drugs, toxicants, or infections; autoimmunity disorders; and cancer angiogenesis, epithelial-mesenchymal transition, chemotherapy resistance, progression, and metabolism. In this review, we discuss the function of BACH proteins in the digestive system, including the liver, gallbladder, esophagus, stomach, small and large intestines, and pancreas. BACH proteins directly target genes or indirectly regulate downstream molecules to promote or inhibit biological phenomena such as inflammation, tumor angiogenesis, and epithelial-mesenchymal transition. BACH proteins are also regulated by proteins, miRNAs, LncRNAs, labile iron, and positive and negative feedback. Additionally, we summarize a list of regulators targeting these proteins. Our review provides a reference for future studies on targeted drugs in digestive diseases. [ABSTRACT FROM AUTHOR]

Ferroptosis is triggered by a chain of intracellular labile iron‐dependent peroxidation of cell membrane phospholipids. Ferroptosis is important not only as a cause of ischaemic and neurodegenerative diseases but also as a mechanism of cancer suppression, and a better understanding of its regulatory mechanism is required. It has become clear that ferroptosis is finely controlled by two oxidative stress‐responsive transcription factors, NRF2 (NF‐E2‐related factor 2) and BACH1 (BTB and CNC homology 1). NRF2 and BACH1 inhibit and promote ferroptosis, respectively, by activating or suppressing the expression of genes in the major regulatory pathways of ferroptosis: intracellular labile iron metabolism, the GSH (glutathione) ‐GPX4 (glutathione peroxidase 4) pathway and the FSP1 (ferroptosis suppressor protein 1)‐CoQ (coenzyme Q) pathway. In addition to this, NRF2 and BACH1 control ferroptosis through the regulation of lipid metabolism and cell differentiation. This multifaceted regulation of ferroptosis by NRF2 and BACH1 is considered to have been acquired during the evolution of multicellular organisms, allowing the utilization of ferroptosis for maintaining homeostasis, including cancer suppression. In terms of cell–cell interaction, it has been revealed that ferroptosis has the property of propagating to surrounding cells along with lipid peroxidation. The regulation of ferroptosis by NRF2 and BACH1 and the propagation phenomenon could be used to realize anticancer cell therapy in the future. In this review, these points will be summarized and discussed. [ABSTRACT FROM AUTHOR]

Macrophages play essential roles in erythrophagocytosis and iron recycling. β‐thalassemia is characterized by a genetic defect in hemoglobin synthesis, which increases the rate of iron recycling. We previously showed that reduced expression of the BTB and CNC homolog 1 (BACH1) gene leads to increased phagocytosis of abnormal RBCs by activated monocytes. However, the mechanisms underlying this abnormal RBC clearance remained unclear. Herein, the spleen and bone marrow cells of β‐thalassemic mice were examined for erythrophagocytosis CD markers and iron‐recycling genes. Higher expression levels of CD47 and CD163 on RBCs and macrophages, respectively, were observed in β‐thalassemic mice than in wild‐type cells. The decreased expression of BACH1 caused an increase in Nrf2, Spic, Slc40a1, and HMOX1 expression in splenic red pulp macrophages of thalassemic mice. To investigate BACH1 regulation, a macrophage cell line was transfected with BACH1‐siRNA. Decreased BACH1 expression caused an increase in CD163 expression; however, the expression levels were lower when the cells were cultured in media supplemented with β‐thalassemia/HbE patient plasma. Additionally, the iron recycling‐related genes SPIC, SLC40A1, and HMOX1 were significantly upregulated in BACH1‐suppressed macrophages. Our findings provide insights into BACH1 regulation, which plays an important role in erythrophagocytosis and iron recycling in thalassemic macrophages. [ABSTRACT FROM AUTHOR]

[Display omitted] • RTA408 alleviates LPS-induced acute lung injury. • RTA408 attenuates LPS-induced epithelial cell ferroptosis in vivo and in vitro. • The inhibitory effect of RTA408 on ferroptosis depends on Bach1. • Upon Bach1 depletion, RTA408 shows weakened protective effect on acute lung injury. The approved traditional Asian medicine RTA408 (Omaveloxolone) has demonstrated potent anti-inflammatory properties in the treatment of Friedreich's ataxia. However, its effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains poorly understood. This study aims to evaluate the effect of RTA408 on LPS-induced ALI and elucidate its underlying mechanisms. In this study, in vivo experiments demonstrated that RTA408 significantly ameliorated LPS-induced mouse ALI, characterized by reduced pathological damage and neutrophil infiltration as well as decreased lung edema of murine lung tissues. Moreover, LPS administration induced ferroptosis in ALI mice, evidenced by increased MDA levels, reduced GSH and SOD activity, and decreased expression of ferroptosis repressors (GPX4 and SLC7A11), whereas RTA408 reversed these changes. Consistently, RTA408 reduced ferroptosis and improved cell damage in LPS-stimulated MLE-12 cells, as evidenced by decreased ROS and MDA levels, increased SOD, GSH activity and ferroptosis repressors expression. Meanwhile, the protective effective of RTA408 on LPS-induced oxidative damage was blocked by ferroptosis inhibitor ferrostatin-1 (Fer-1). Mechanistic studies demonstrated that RTA408 inhibited the expression and nuclear translocation of Bach1, and the anti-ferroptosis effect was diminished by Bach1 siRNA or Bach1 knockout (Bach1−/−) mice. Furthermore, Bach1−/− mice exhibited attenuated ALI induced by LPS compared to wild-type (WT) mice, and the protective effect of RTA408 on LPS-challenged ALI was not observed in Bach1−/− mice. In conclusion, our data suggested that RTA408 alleviates LPS-induced ALI by interfering Bach1-mediated ferroptosis and might be a novel candidate for LPS-induced ALI/ARDS therapy. [ABSTRACT FROM AUTHOR]

In sickle cell disease (SCD), heme released during intravascular hemolysis promotes oxidative stress, inflammation, and vaso-occlusion. Conversely, free heme can also activate expression of antioxidant and globin genes. Heme binds to the transcription factor BACH1, which represses NRF2-mediated gene transcription. ASP8731, is a selective small molecule inhibitor of BACH1. We investigated the ability of ASP8731 to modulate pathways involved in SCD pathophysiology. In HepG2 liver cells, ASP8731 increased HMOX1 and FTH1 mRNA. In pulmonary endothelial cells, ASP8731 decreased VCAM1 mRNA in response to TNF-α and blocked a decrease in glutathione in response to hemin. Townes-SS mice were gavaged once per day for 4 weeks with ASP8731, hydroxyurea (HU) or vehicle. Both ASP8731 and HU inhibited heme-mediated microvascular stasis and in combination, ASP8731 significantly reduced microvascular stasis compared to HU alone. In Townes-SS mice, ASP8731 and HU markedly increased heme oxygenase-1 and decreased hepatic ICAM-1, NF-kB phospho-p65 protein expression in the liver, and white blood cell counts. In addition, ASP8731 increased gamma-globin expression and HbF+ cells (F-cells) as compared to vehicle-treated mice. In human erythroid differentiated CD34+ cells, ASP8731 increased HGB mRNA and increased the percentage of F-cells 2-fold in manner similar to HU. ASP8731 and HU when given together induced more HbF+ cells compared to either drug alone. In CD34+ cells from one donor that was non-responsive to HU, ASP8731 induced HbF+ cells ~2-fold. ASP8731 and HU also increased HBG and HBA, but not HBB mRNA in erythroid differentiated CD34+ cells derived from SCD patients. These data indicate that BACH1 may offer a new therapeutic target to treat SCD.

Multiple lines of evidences have unraveled the emerging role of ferroptosis in the pathophysiological process of acute lung injury (ALI). In this study, we aimed to decipher the role of BACH1 in the onset and progression of ALI with a focus on ferroptosis and elucidated potential molecular mechanism. We observed that BACH1 expression was drastically elevated in BEAS-2B cells upon exposure to LPS. In the functional aspect, BACH1 deletion exerted an anti-inflammatory property, featured by decreased the secretion of several cytokines including TNF-α, IL-1β and IL-6 in the face of LPS challenge. What's more important, BACH1 knockout evidently repressed LPS-triggered oxidative stress damage, as evidenced by reduced reactive oxygen species (ROS) production and malondialdehyde (MDA) generation, accompanied with the elevated the activities of superoxide dismutase (SOD), GSH-Px and CAT. Meanwhile, ablation of BACH1 restrained LPS-elicited ferroptosis, as characterized by decreased iron content and PTGS2 expression, accompanied with increased expression of SLC7A11 and GPX4. In terms of mechanism, Nrf2/HO-1 signaling inhibitor effectively abrogated the beneficial effects of BACH1 inhibition on LPS-stimulated inflammation, oxidative damage and ferroptosis. Taken together, these preceding outcomes strongly illuminated that BACH1 was a novel regulator of LPS-evoked injury through regulation of inflammation response, oxidative stress and ferroptosis via activation Nrf2/HO-1 signaling, indicating that BACH1 may represent as a promising novel therapeutic candidate for ALI treatment. • BACH1 was aberrantly expressed in LPS-induced bronchial epithelial cells. • Deficiency of BACH1 mitigated LPS-elicited inflammatory response, oxidative stress damage and ferroptosis of BEAS-2B cells. • Interference of BACH1 protected against LPS-evoked injury via the activation of Nrf2/HO-1 signaling. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cell‐derived conditioned medium (MSC‐CM) improves cardiac function after myocardial infarction; however, this cardioprotective effect is moderate and transient. Lipopolysaccharide (LPS) pretreatment partially improves MSC‐CM‐mediated cardioprotective effects owing to the presence of paracrine factors. However, the mechanism underlying these improved effects remains unknown. To study the effect of LPS‐pretreated MSC‐CM on hypoxia/reoxygenation (H/R)‐induced injury, MSCs were treated with or without LPS (400 ng/mL) for 48 h, and the supernatant was collected (MSC‐CM). Subsequently, H9c2 cells were co‐cultured with Nor‐CM (CM derived from LPS‐untreated MSCs) and LPS‐CM (CM derived from LPS‐pretreated MSCs) for 24 h and subjected to H/R. MSC‐CM inhibited the progression of H/R‐induced injury in H9c2 cells, and this protective effect was enhanced via LPS pretreatment as evidenced by the improved apoptosis assessment index (i.e. caspase‐3 and B‐cell lymphoma‐2 [Bcl‐2] expression) and decreased levels of lactic dehydrogenase (LDH) and cardiac troponin (cTn). In addition, the results of haematoxylin–eosin staining (H&E), transmission electron microscopy (TEM) and TdT‐mediated dUTP nick‐end labelling (TUNEL) validated that MSC‐CM inhibited H/R‐induced injury in H9c2 cardiomyocytes. LPS pretreatment downregulated the expression of high mobility group box‐1 (HMGB1) and BTB and CNC homology‐1 (Bach1) proteins in MSCs but upregulated the expression of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and insulin‐like growth factor (IGF). HMGB1 knockdown (MSC/siHMGB1‐CM) significantly decreased the expression of Bach1 and increased the expression of VEGF, HGF and IGF. Bach1 knockdown (MSC/siBach1‐CM) did not alter the production of HMGB1 but increased the expression of VEGF and IGF. LPS pretreatment did not alter the expression of the paracrine factors VEGF and HGF in the MSC/siHMGB1 group but increased their expression in the MSC/siBach1 group. The myocyte anti‐apoptotic effects of MSCs/siBach1‐CM were similar to those of untreated MSCs, which were not enhanced by LPS. LPS‐pretreated MSC‐CM protects H9c2 cells against H/R‐induced injury partly through the HMGB1/Bach1 signalling pathway. [ABSTRACT FROM AUTHOR]

The ever-increasing chemoresistance of osteosarcoma (OS) has been observed in the recent decades, impeding OS therapeutic improvement and posing an urgency to exploit to the alternative and/or supplementary therapies for the optimization of OS chemotherapeutic regimen. Ferroptosis, a regulated cell death, has been identified as a natural anticancer mechanism as well as a synergist for chemotherapeutics in various cancers. Herein, we affirmed the tumor-suppressing properties of eriodictyol and illustrated that its antitumor effects might ascribe to the ferroptosis-inducing activity, in which eriodictyol could bind with BACH1 to repress the transcription and translation of GPX4 and eventually result in the GPX4-related ferroptosis. Further investigation found that eriodictyol could exhibit a synergistic effect with cisplatin, facilitating the antitumor effects of cisplatin. Lastly, through utilizing hollow mesoporous prussian blue nanocubes loaded with eriodictyol and cisplatin, we formed the ferroptosis-synergistic nanocomplexes to facilitate OS cells ferroptosis and cisplatin sensitivity. Through direct catalytic oxidation of unsaturated lipids, exogenous iron delivery, GSH exhaustion, and GPX4 transcriptional inhibition, this ferroptosis-synergistic nanocomplex could excellently enhance OS cells ferroptosis in both vitro and vivo, with no obvious organ injury observed. Therefore, our ferroptosis-synergistic nanocomplex may represent a promising alternative therapeutic strategy for OS patients., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Ethics Committee of Xiangya Hospital of Central South University. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

BTB domain and CNC homolog 1 (BACH1) belongs to the family of basic leucine zipper proteins and is expressed in most mammalian tissues. It can regulate its own expression and play a role in transcriptionally activating or inhibiting downstream target genes. It has a crucial role in various biological processes, such as oxidative stress, cell cycle, heme homeostasis, and immune regulation. Recent research highlights BACH1's significant regulatory roles in a series of conditions, including stem cell pluripotency maintenance and differentiation, growth, senescence, and apoptosis. BACH1 is closely associated with cardiovascular diseases and contributes to angiogenesis, atherosclerosis, restenosis, pathological cardiac hypertrophy, myocardial infarction, and ischemia/reperfusion (I/R) injury. BACH1 promotes tumor cell proliferation and metastasis by altering tumor metabolism and the epithelial-mesenchymal transition phenotype. Moreover, BACH1 appears to show an adverse role in diseases such as neurodegenerative diseases, gastrointestinal disorders, leukemia, pulmonary fibrosis, and skin diseases. Inhibiting BACH1 may be beneficial for treating these diseases. This review summarizes the role of BACH1 and its regulatory mechanism in different cell types and diseases, proposing that precise targeted intervention of BACH1 may provide new strategies for human disease prevention and treatment., (© 2025 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Abstract Background Growing evidence suggests that cancer stem cells (CSCs) are responsible for cancer initiation in tumors. Bach1 has been identified to contribute to several tumor progression, including lung cancer. The role of Bach1 in CSCs remains poorly known. Therefore, the function of Bach1 on lung CSCs was focused currently. Methods The expression of Bach1, CD133, CD44, Sox2, Nanog and Oct4 mRNA was assessed using Real-Time Quantitative Reverse Transcription PCR (RT-qPCR). Protein expression of Bach1, CD133, CD44, Sox2, Nanog, Oct4, p53, BCL2, BAX, p-p38, p-AKT1, c-Fos and c-Jun protein was analyzed by western blotting. 5-ethynyl-29-deoxyuridine (EdU), colony formation, Flow cytometry analysis and transwell invasion assay were carried out to analyze lung cancer cell proliferation, apoptosis and invasion respectively. Tumor sphere formation assay was utilized to evaluate spheroid capacity. Flow cytometry analysis was carried out to isolate CD133 or CD44 positive lung cancer cells. The relationship between Bach1 and CD44 was verified using ChIP-qPCR and dual-luciferase reporter assay. Xenograft tumor tissues were collected for hematoxylin and eosin (HE) staining and IHC analysis to evaluate histology and Ki-67. Results The ratio of CD44 + CSCs from A549 and SPC-A1 cells were significantly enriched. Tumor growth of CD44 + CSCs was obviously suppressed in vivo compared to CD44− CSCs. Bach1 expression was obviously increased in CD44 + CSCs. Then, via using the in vitro experiment, it was observed that CSCs proliferation and invasion were greatly reduced by the down-regulation of Bach1 while cell apoptosis was triggered by knockdown of Bach1. Loss of Bach1 was able to repress tumor-sphere formation and tumor-initiating CSC markers. A repression of CSCs growth and metastasis of shRNA-Bach1 was confirmed using xenograft models and caudal vein injection. The direct interaction between Bach1 and CD44 was confirmed by ChIP-qPCR and dual-luciferase reporter assay. Furthermore, mitogen-activated protein kinases (MAPK) signaling pathway was selected and we proved the effects of Bach1 on lung CSCs were associated with the activation of the MAPK pathway. As manifested, loss of Bach1 was able to repress p-p38, p-AKT1, c-Fos, c-Jun protein levels in lung CSCs. Inhibition of MAPK signaling remarkably restrained lung CSCs growth and CSCs properties induced by Bach1 overexpression. Conclusion In summary, we imply that Bach1 demonstrates great potential for the treatment of lung cancer metastasis and recurrence via activating CD44 and MPAK signaling.