BACH to the ferroptosis.

Ferroptosis is 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 the key molecules in ferroptosis. Erastin and RSL3, known as inhibitors of system Xc - and GPX4, respectively, are commonly used as ferroptosis inducers. BTB and CNC homology 1 (BACH1), a heme-binding transcription repressor, promotes pro-ferroptotic signaling, and therefore, Bach1-deficient cells are resistant to ferroptosis. Irikura et al. constructed Bach1-re-expressing immortalized mouse embryonic fibroblasts (iMEFs) from Bach1-/- mice, which induce ferroptosis simply by the depletion of 2-mercaptoethanol from the culture medium (J. Biochem. 2023; 174:239-252). Transcriptional repression by re-expressed BACH1 induces suppressed glutathione synthesis and increases labile iron. Furthermore, the 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.

m6A-activated BACH1 exacerbates ferroptosis by epigenetic suppression HSPB1 in severe acute pancreatitis.

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.

Intracellular biliverdin dynamics during ferroptosis.

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 among 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.

RTA408 alleviates lipopolysaccharide-induced acute lung injury via inhibiting Bach1-mediated ferroptosis.

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.

Absolute quantification of BACH1 and BACH2 transcription factors in B and plasma cells reveals their dynamic changes and unique roles.

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, while BACH2 increased. In plasma cells, BACH1 increased back to the same extent as in naïve B cells, while 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.

Loss of BACH1 improves osteogenic differentiation in glucocorticoid-induced hBMSCs through restoring autophagy.

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.

Renal denervation improves mitochondrial oxidative stress and cardiac hypertrophy through inactivating SP1/BACH1-PACS2 signaling.

BACKGROUND: Renal denervation (RDN) has been proved to relieve cardiac hypertrophy; however, its detailed mechanisms remain obscure. This study investigated the detailed protective mechanisms of RDN against cardiac hypertrophy during hypertensive heart failure (HF). METHODS: Male 5-month-old spontaneously hypertension (SHR) rats were used in a HF rat model, and male Wistar-Kyoto (WKY) rats of the same age were used as the baseline control. Myocardial hypertrophy and fibrosis were evaluated by hematoxylin-eosin (HE) staining and Masson staining. The expression of target molecule was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot, immunohistochemical and immunofluorescence, respectively. Cardiomyocyte hypertrophy was induced by norepinephrine (NE) in H9c2 cells in vitro and evaluated by brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP), ß-myosin heavy chain (ß-MHC), and α-myosin heavy chain (α-MHC) levels. Oxidative stress was determined by malondialdehyde (MDA) level, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) enzyme activities. Mitochondrial function was measured by mitochondrial membrane potential, adenosine triphosphate (ATP) production, mitochondrial DNA (mtDNA) number, and mitochondrial complex I-IV activities. Molecular mechanism was assessed by dual luciferase reporter and chromatin immunoprecipitation (ChIP) assays. RESULTS: RDN decreased sympathetic nerve activity, attenuated myocardial hypertrophy and fibrosis, and improved cardiac function in the rat model of HF. In addition, RDN ameliorated mitochondrial oxidative stress in myocardial tissues as evidenced by reducing MDA and mitochondrial reactive oxygen species (ROS) levels, and enhancing SOD and GSH-Px activities. Moreover, phosphofurin acid cluster sorting protein 2 (PACS-2) and broad-complex, tramtrak and bric à brac (BTB) domain and cap'n'collar (CNC) homolog 1 (BACH1) were down-regulated by RDN. In NE-stimulated H9c2 cells, PACS-2 and BACH1 levels were markedly elevated, and knockdown of them could suppress NE-induced oxidative stress, cardiomyocyte hypertrophy, fibrosis, as well as mitochondrial dysfunction. Transforming growth factor beta1(TGFß1)/SMADs signaling pathway was inactivated by RDN in the HF rats, which sequentially inhibited specificity protein 1 (SP1)-mediated transcription of PACS2 and BACH1. CONCLUSION: Collectively, these data demonstrated that RDN improved cardiac hypertrophy and sympathetic nerve activity of HF rats via repressing BACH1 and PACS-2-mediated mitochondrial oxidative stress by inactivating TGF-ß1/SMADs/SP1 pathway, which shed lights on the cardioprotective mechanism of RDN in HF.

Targeting the NRF2 pathway for disease modification in neurodegenerative diseases: mechanisms and therapeutic implications.

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.

Ferroptosis regulation by Cap'n'collar family transcription factors.

Ferroptosis is an iron-dependent cell death mechanism that may be important to prevent tumor formation and useful as a target for new cancer therapies. Transcriptional networks play a crucial role in shaping ferroptosis sensitivity by regulating the expression of transporters, metabolic enzymes, and other proteins. The Cap'n'collar (CNC) protein NFE2 like bZIP transcription factor 2 (NFE2L2, also known as NRF2) is a key regulator of ferroptosis in many cells and contexts. Emerging evidence indicates that the related CNC family members, BTB domain and CNC homolog 1 (BACH1) and NFE2 like bZIP transcription factor 1 (NFE2L1), also have roles in ferroptosis regulation. Here, we comprehensively review the role of CNC transcription factors in governing cellular sensitivity to ferroptosis. We describe how CNC family members regulate ferroptosis sensitivity through modulation of iron, lipid, and redox metabolism. We also use examples of ferroptosis regulation by CNC proteins to illustrate the flexible and highly context-dependent nature of the ferroptosis mechanism in different cells and conditions.

Disruption of BACH1 Protects AC16 Cardiomyocytes Against Hypoxia/Reoxygenation-Evoked Injury by Diminishing CDKN3 Transcription.

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-1ß) 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.

Remifentanil represses oxidative stress to relieve hepatic ischemia/reperfusion injury via regulating BACH1/PRDX1 axis.

BACKGROUND: Hepatic ischemia-reperfusion injury (HIRI) is a major cause of liver dysfunction after clinical liver surgery, which seriously affects the prognosis of patients. Remifentanil (RE) has been verified to attenuate HIRI. However, its therapeutic mechanism is still unclear. This study aimed to explore the protective mechanism of RE against HIRI. METHODS: A mouse HIRI model and an in vitro model of hypoxia/reoxygenation (H/R)-stimulated AML12 hepatocytes were established. Liver histopathological changes were evaluated by hematoxylin and eosin (HE) staining. Oxidative stress damage was assessed by malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) levels. Liver function was determined by serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH). and adenosine triphosphate (ATP) levels. Cell counting kit-8 (CCK-8) assessed cell viability. Apoptosis was measured by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) and flow cytometry. The levels of inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA) kits. The differentially expressed genes were evaluated by mRNA microarray analysis. Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR) were conducted to detect molecule expression. The binding of BTB and CNC homology 1 (BACH1) to peroxiredoxin 1 (PRDX1) was validated by chromatin immunoprecipitation (ChIP) and dual luciferase reporter assay. RESULTS: RE treatment improved liver function, and repressed oxidative stress damage and apoptosis in HIRI mice. Nine differentially expressed genes in the liver tissues of HIRI mice were selected by microarray analysis, among which BACH1 was down-regulated and PRDX1 was up-regulated after RE treatment. In addition, BACH1 directly bound to the promoter region of PRDX1 to inhibit its transcription and expression, which led to oxidative stress injury. BACH1 overexpression or PRDX1 silencing could counteract the beneficial effects of RE against HIRI. CONCLUSION: RE suppressed oxidative stress injury and inflammation via inactivation of the BACH1/PRDX1 axis, thereby ameliorating HIRI. Our findings enrich the understanding of the protective mechanisms of RE against HIRI, and provide novel evidence for its clinical application.

The Growth Inhibitory Effect of Resveratrol and Gallic Acid on Prostate Cancer Cell Lines through the Alteration of Oxidative Stress Balance: the Interplay between Nrf2, HO-1, and BACH1 Genes.

BACKGROUND: The association between oxidative stress and prostate cancer (PC) has been demonstrated both epidemiologically and experimentally. Balance in reactive oxygen species (ROS) levels depends on multiple factors, such as the expression of Nrf2, HO-1, and BACH1 genes. Natural polyphenols, such as resveratrol (RSV) and gallic acid (GA), affect cellular oxidative profiles. OBJECTIVE: The present study investigated the possible effects of GA and RSV on the oxidative profiles of PC3 and DU145 cells, as well as Nrf2, HO-1, and BACH1 gene expression to achieve an understanding of the mechanisms involved. METHODS: PC3 and DU145 cells were treated with ascending concentrations of RSV and GA for 72h. Then cell growth and mRNA expression of Nrf2, HO-1, and BACH1 genes were analyzed by real-time PCR. Various spectrophotometric analyses were performed to measure oxidative stress markers. RESULTS: RSV and GA significantly decreased the growth of PC3 and DU145 cells compared to the control group in a concentration-dependent manner. RSV and GA also decreased ROS production in PC3 cells, but in DU145 cells, only the latter polyphenol significantly decreased ROS content. In addition, RSV and GA had ameliorating effects on SOD, GR, GPX, and CAT activities and GSH levels in both cell lines. Also, RSV and GA induced HO- 1 and Nrf2 gene expression in both cell lines. BACH1 gene expression was induced by RSV only at lower concentrations, in contrast to GA in both cell lines. CONCLUSION: Our data suggest that RSV and GA can prevent the growth of prostate cancer cells by disrupting oxidative stress-related pathways, such as changes in Nrf2, HO-1, and BACH1 gene expression.

Sophoricoside ameliorates methicillin-resistant Staphylococcus aureus-induced acute lung injury by inhibiting Bach1/Akt pathway.

BACKGROUND: The lack of effective treatments for methicillin-resistant Staphylococcus aureus (MRSA) infection, which often leads to severe acute lung injury (ALI), poses a grave threat to human life. Sophoricoside (SOP), an isoflavone glycoside abundant in the fruit of traditional Chinese herbal Sophora japonica l., showed anti-inflammatory effects against atopic dermatitis, allergic inflammation, and lipopolysaccharide-induced ALI. However, its effect and underlying mechanism on MRSA-induced ALI remain unclear. PURPOSE: The aim of this study is to assess the protective effect of SOP in MRSA-induced ALI and elucidate its underlying molecular mechanisms. METHODS: In vivo experiments were conducted using wild-type mice to establish MRSA-induced ALI mouse model, and the effects of SOP on ALI were evaluated by hematoxylin-eosin staining, flow cytometry, quantitative real-time polymerase chain reaction, and several biochemical indicators. Adoptive transfer experiments and BTB and CNC homology 1 knockout (Bach1-/-) mice were also utilized in this study. In vitro studies employed murine macrophages RAW264.7 cells, primary bone marrow-derived macrophages (BMDMs), and primary lung macrophages to explore the underlying molecular mechanisms. RESULTS: The administration of SOP ameliorated MRSA-induced ALI by improving pulmonary histological damages, reducing neutrophil infiltration, suppressing oxidative stress levels, and decreasing the expression of inflammatory cytokines. In isolation experiments with ALI mouse lung macrophages and macrophage adoptive transfer experiments, SOP prevented macrophage activation, thereby reducing the production of proinflammatory cytokines. In vitro experiments demonstrated that SOP decreased the expression of inflammatory mediators in lipoteichoic acid (LTA)-stimulated RAW264.7 cells, BMDMs, and primary lung macrophages. Additionally, SOP inhibited protein kinase B (Akt) phosphorylation and treatment with MK2206-a specific inhibitor of Akt-eliminated SOP's ability to suppress LTA-stimulated macrophage inflammation. Furthermore, stimulation with LTA or MRSA up-regulated Bach1 expression; however, deletion of Bach1 abolished the inhibitory effect of SOP on p-Akt activation as well as inflammation and ALI development. CONCLUSION: This study provides the first evidence that SOP effectively mitigates MRSA-induced ALI via suppressing macrophage activation through the inhibition of Bach1/Akt pathway. These findings highlight the potential of SOP as a novel therapeutic agent for treating MRSA-induced ALI.

MiR-196a-5p hinders vascular smooth muscle cell proliferation and vascular remodeling via repressing BACH1 expression.

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.

FTO alleviated ferroptosis in septic cardiomyopathy via mediating the m6A modification of BACH1.

Sepsis is a global health challenge that results in systemic inflammation, oxidative stress, and multi-organ dysfunction, with the heart being particularly susceptible. This study aimed to elucidate the effect of FTO, a key regulator in m6A methylation in septic cardiomyopathy, and its potential therapeutic implications. Cellular and animal models of septic myocardial injury were established. Moreover, it was revealed that ferroptosis, which is a form of programmed necrosis occurring with iron dependence, was activated within cardiomyocytes during septic conditions. The overexpression of FTO-suppressed ferroptosis alleviated heart inflammation and dysfunction and improved survival rates in vivo. However, the protective effects of FTO were attenuated by the overexpression of BACH1, which is a molecule negatively correlated with FTO. Mechanistically, FTO modulated the m6A modification of BACH1, suggesting a complex interplay in the regulation of cardiomyocyte damage and sepsis. Our findings reveal the potential of targeting the FTO/BACH1 axis and ferroptosis inhibitors as therapeutic strategies for sepsis-induced cardiac injuries.

BACH1 impairs hepatocyte regeneration after hepatectomy with repeated ischemia/reperfusion by reprogramming energy metabolism and exacerbating oxidative stress.

BTB and CNC homology 1 (BACH1) regulates biological processes, including energy metabolism and oxidative stress. Insufficient liver regeneration after hepatectomy remains an issue for surgeons. The Pringle maneuver is widely used during hepatectomy and induces ischemia/reperfusion (I/R) injury in hepatocytes. A rat model of two-thirds partial hepatectomy with repeated I/R treatment was used to simulate clinical hepatectomy with Pringle maneuver. Delayed recovery of liver function after hepatectomy with the repeated Pringle maneuver in clinic and impaired liver regeneration in rat model were observed. Highly elevated lactate levels, along with reduced mitochondrial complex III and IV activities in liver tissues, indicated that the glycolytic phenotype was promoted after hepatectomy with repeated I/R. mRNA expression profile analysis of glycolysis-related genes in clinical samples and further verification experiments in rat models showed that high BACH1 expression levels correlated with the glycolytic phenotype after hepatectomy with repeated I/R. BACH1 overexpression restricted the proliferative potential of hepatocytes stimulated with HGF. High PDK1 expression and high lactate levels, together with low mitochondrial complex III and IV activities and reduced ATP concentrations, were detected in BACH1-overexpressing hepatocytes with HGF stimulation. Moreover, HO-1 expression was downregulated, and oxidative stress was exacerbated in the BACH1-overexpressing hepatocytes with HGF stimulation. Cell experiments involving repeated hypoxia/reoxygenation revealed that reactive oxygen species accumulation triggered the TGF-ß1/BACH1 axis in hepatocytes. Finally, inhibiting BACH1 with the inhibitor hemin effectively restored the liver regenerative ability after hepatectomy with repeated I/R. These results provide a potential therapeutic strategy for impaired liver regeneration after repeated I/R injury.

BACH1 inhibits senescence, obesity, and short lifespan by ferroptotic FGF21 secretion.

Ferroptosis is a type of regulated cell death characterized by iron-dependent lipid peroxidation. A model cell system is constructed to induce ferroptosis by re-expressing the transcription factor BACH1, a potent ferroptosis inducer, in immortalized mouse embryonic fibroblasts (iMEFs). The transfer of the culture supernatant from ferroptotic iMEFs activates the proliferation of hepatoma cells and other fibroblasts and suppresses cellular senescence-like features. The BACH1-dependent secretion of the longevity factor FGF21 is increased in ferroptotic iMEFs. The anti-senescent effects of the culture supernatant from these iMEFs are abrogated by Fgf21 knockout. BACH1 activates the transcription of Fgf21 by promoting ferroptotic stress and increases FGF21 protein expression by suppressing its autophagic degradation through transcriptional Sqstm1 and Lamp2 repression. The BACH1-induced ferroptotic FGF21 secretion suppresses obesity in high-fat diet-fed mice and the short lifespan of progeria mice. The inhibition of these aging-related phenotypes can be physiologically significant regarding ferroptosis.

PRMT1 promotes epigenetic reprogramming associated with acquired chemoresistance in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) carries a dismal prognosis due to therapeutic resistance. We show that PDAC cells undergo global epigenetic reprogramming to acquire chemoresistance, a process that is driven at least in part by protein arginine methyltransferase 1 (PRMT1). Genetic or pharmacological PRMT1 inhibition impairs adaptive epigenetic reprogramming and delays acquired resistance to gemcitabine and other common chemo drugs. Mechanistically, gemcitabine treatment induces translocation of PRMT1 into the nucleus, where its enzymatic activity limits the assembly of chromatin-bound MAFF/BACH1 transcriptional complexes. Cut&Tag chromatin profiling of H3K27Ac, MAFF, and BACH1 suggests a pivotal role for MAFF/BACH1 in global epigenetic response to gemcitabine, which is confirmed by genetically silencing MAFF. PRMT1 and MAFF/BACH1 signature genes identified by Cut&Tag analysis distinguish gemcitabine-resistant from gemcitabine-sensitive patient-derived xenografts of PDAC, supporting the PRMT1-MAFF/BACH1 epigenetic regulatory axis as a potential therapeutic avenue for improving the efficacy and durability of chemotherapies in patients of PDAC.

Role of BACH1 in multiple myeloma.

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.

BACH1 transcriptionally upregulates FOSL2 to induce M2 macrophages phenotype by activating TGFß/SMAD signaling to promote the transformation of lung fibroblasts into myofibroblasts.

Pulmonary fibrosis is a chronic and progressive lung disorder. The pro-fibrosis factors induced by M2 macrophage phenotype promote the differentiation of fibroblasts into myofibroblasts, which is essential for pulmonary fibrosis. We aimed to explore the role and mechanism of BTB domain and CNC homology 1 (BACH1) in pulmonary fibrosis. BACH1 was knocked down in THP-1 polarized M2 macrophages with or without FOS-like antigen 2 (FOSL2) overexpression, the expression of M2 macrophage markers was detected. Cell viability, migration, invasion and extracellular matrix (ECM) accumulation were estimated by CCK-8, wound healing, transwell, western bot and immunofluorescence staining. Luciferase reporter and chromatin immunoprecipitation assays were used to verify the binding of BACH1 to FOSL2 promotor region. In vivo, a bleomycin (BLM)-induced pulmonary fibrosis mice model was established to evaluate the effect of BACH1 silencing on the histopathological changes, M2 macrophage phenotype and extracellular matrix (ECM) deposition. Expression of proteins was assessed with western blot. Results indicated that BACH1 expression was upregulated in M2 macrophages polarized from THP-1 cells. BACH1 deficiency inhibited the polarization of THP-1 to the M2 macrophage phenotype to promote the transformation of lung fibroblasts into myofibroblasts. Additionally, BACH1 could transcriptionally activate FOSL2 expression in THP-1-derived macrophages to upregulate TGFß/SMAD signaling in HFL-1 cells. The animal experiments indicated that BACH1 knockdown alleviated BLM-induced pulmonary fibrosis, M2 macrophage polarization and inactivated FOSL2/TGFß/SMAD signaling in mice lung tissues. Together, this finding suggests BACH1/FOSL2 may be useful therapeutic targets for the treatment of pulmonary fibrosis.