TCEB2/HIF1A signaling axis promotes chemoresistance in ovarian cancer cells by enhancing glycolysis and angiogenesis.

Ovarian cancer is an extremely malignant gynaecological tumour with a poor patient prognosis and is often associated with chemoresistance. Thus, exploring new therapeutic approaches to improving tumour chemosensitivity is important. The expression of transcription elongation factor B polypeptide 2 (TCEB2) gene is reportedly upregulated in ovarian cancer tumour tissues with acquired resistance, but the specific mechanism involved in tumour resistance remains unclear. In this study, we found that TCEB2 was abnormally highly expressed in cisplatin-resistant tumour tissues and cells. TCEB2 silencing also inhibited the growth and glycolysis of SKOV-3/cisplatin (DDP) and A2780/DDP cells. We further incubated human umbilical vein endothelial cells (HUVECs) with culture supernatants from cisplatin-resistant cells having TCEB2 knockdown. Results revealed that the migration, invasion, and angiogenesis of HUVECs were significantly inhibited. Online bioinformatics analysis revealed that the hypoxia-inducible factor-1A (HIF-1A) protein may bind to TCEB2, and TCEB2 silencing inhibited SKOV-3/DDP cell growth and glycolysis by downregulating HIF1A expression. Similarly, TCEB2 promoted HUVEC migration, invasion, and angiogenesis by upregulating HIF1A expression. In vivo experiments showed that TCEB2 silencing enhanced the sensitivity of ovarian cancer nude mice to cisplatin and that TCEB2 knockdown inhibited the glycolysis and angiogenesis of tumour cells. Our findings can serve as a reference for treating chemoresistant ovarian cancer.

Magnamosis improves the healing of gastrojejunal anastomosis and down-regulates TGF-ß1 and HIF-1α in rats.

This study elucidated the unique pathological features of tissue healing by magnamosis and revealed the changes in landmark molecule expression levels related to collagen synthesis and tissue hypoxia. Forty-eight male Sprague-Dawley rats were divided into the magnamosis and suture anastomosis groups, and gastrojejunal anastomosis surgery was performed. Rats were dissected at 6, 24, and 48 h and 5, 6, 8, 10, and 12 days postoperatively. Hematoxylin, eosin, and Masson's trichrome staining were used to evaluate granulation tissue proliferation and collagen synthesis density at the anastomosis site. Immunohistochemistry was used to measure TGF-ß1 and HIF-1α expression levels. Magnamosis significantly shortened the operation time, resulting in weaker postoperative abdominal adhesions (P < 0.0001). Histopathological results showed a significantly lower granulation area in the magnamosis group than in the suture anastomosis group (P = 0.0388), with no significant difference in the density of collagen synthesis (P = 0.3631). Immunohistochemistry results indicated that the magnamosis group had significantly lower proportions of TGF-ß1-positive cells at 24 (P = 0.0052) and 48 h (P = 0.0385) postoperatively and HIF-1α-positive cells at 24 (P = 0.0402) and 48 h postoperatively (P = 0.0005). In a rat model of gastrojejunal anastomosis, magnamosis leads to improved tissue healing at the gastrojejunal anastomosis, associated with downregulated expression levels of TGF-ß1 and HIF-1α.

Citrullination modulation stabilizes HIF-1α to promote tumour progression.

Citrullination plays an essential role in various physiological or pathological processes, however, whether citrullination is involved in regulating tumour progression and the potential therapeutic significance have not been well explored. Here, we find that peptidyl arginine deiminase 4 (PADI4) directly interacts with and citrullinates hypoxia-inducible factor 1α (HIF-1α) at R698, promoting HIF-1α stabilization. Mechanistically, PADI4-mediated HIF-1αR698 citrullination blocks von Hippel-Lindau (VHL) binding, thereby antagonizing HIF-1α ubiquitination and subsequent proteasome degradation. We also show that citrullinated HIF-1αR698, HIF-1α and PADI4 are highly expressed in hepatocellular carcinoma (HCC) tumour tissues, suggesting a potential correlation between PADI4-mediated HIF-1αR698 citrullination and cancer development. Furthermore, we identify that dihydroergotamine mesylate (DHE) acts as an antagonist of PADI4, which ultimately suppresses tumour progression. Collectively, our results reveal citrullination as a posttranslational modification related to HIF-1α stability, and suggest that targeting PADI4-mediated HIF-1α citrullination is a promising therapeutic strategy for cancers with aberrant HIF-1α expression.

Activating UCHL1 through the CRISPR activation system promotes cartilage differentiation mediated by HIF-1α/SOX9.

Developing strategies to enhance cartilage differentiation in mesenchymal stem cells and preserve the extracellular matrix is crucial for successful cartilage tissue reconstruction. Hypoxia-inducible factor-1α (HIF-1α) plays a pivotal role in maintaining the extracellular matrix and chondrocyte phenotype, thus serving as a key regulator in chondral tissue engineering strategies. Recent studies have shown that Ubiquitin C-terminal hydrolase L1 (UCHL1) is involved in the deubiquitylation of HIF-1α. However, the regulatory role of UCHL1 in chondrogenic differentiation has not been investigated. In the present study, we initially validated the promotive effect of UCHL1 expression on chondrogenesis in adipose-derived stem cells (ADSCs). Subsequently, a hybrid baculovirus system was designed and employed to utilize three CRISPR activation (CRISPRa) systems, employing dead Cas9 (dCas9) from three distinct bacterial sources to target UCHL1. Then UCHL1 and HIF-1α inhibitor and siRNA targeting SRY-box transcription factor 9 (SOX9) were used to block UCHL1, HIF-1α and SOX9, respectively. Cartilage differentiation and chondrogenesis were measured by qRT-PCR, immunofluorescence and histological staining. We observed that the CRISPRa system derived from Staphylococcus aureus exhibited superior efficiency in activating UCHL1 compared to the commonly used the CRISPRa system derived from Streptococcus pyogenes. Furthermore, the duration of activation was extended by utilizing the Cre/loxP-based hybrid baculovirus. Moreover, our findings show that UCHL1 enhances SOX9 expression by regulating the stability and localization of HIF-1α, which promotes cartilage production in ADSCs. These findings suggest that activating UCHL1 using the CRISPRa system holds significant potential for applications in cartilage regeneration.

HIF1A-AS2 promotes the metabolic reprogramming and progression of colorectal cancer via miR-141-3p/FOXC1 axis.

lncRNA can regulate tumorigenesis development and distant metastasis of colorectal cancer (CRC). However, the detailed molecular mechanisms are still largely unknown. Using RNA-sequencing data, RT-qPCR, and FISH assay, we found that HIF1A-AS2 was upregulated in CRC tissues and associated with poor prognosis. Functional experiments were performed to determine the roles of HIF1A-AS2 in tumor progression and we found that HIF1A-AS2 can promote the proliferation, metastasis, and aerobic glycolysis of CRC cells. Mechanistically, HIF1A-AS2 can promote FOXC1 expression by sponging miR-141-3p. SP1 can transcriptionally activate HIF1A-AS2. Further, HIF1A-AS2 can be packaged into exosomes and promote the malignant phenotype of recipient tumor cells. Taken together, we discovered that SP1-induced HIF1A-AS2 can promote the metabolic reprogramming and progression of CRC via miR-141-3p/FOXC1 axis. HIF1A-AS2 is a promising diagnostic marker and treatment target in CRC.

PPARγ Agonist Pioglitazone Prevents Hypoxia-induced Cardiac Dysfunction by Reprogramming Glucose Metabolism.

The heart relies on various defense mechanisms, including metabolic plasticity, to maintain its normal structure and function under high-altitude hypoxia. Pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ), sensitizes insulin, which in turn regulates blood glucose levels. However, its preventive effects against hypoxia-induced cardiac dysfunction at high altitudes have not been reported. In this study, pioglitazone effectively prevented cardiac dysfunction in hypoxic mice for 4 weeks, independent of its effects on insulin sensitivity. In vitro experiments demonstrated that pioglitazone enhanced the contractility of primary cardiomyocytes and reduced the risk of QT interval prolongation under hypoxic conditions. Additionally, pioglitazone promoted cardiac glucose metabolic reprogramming by increasing glycolytic capacity; enhancing glucose oxidation, electron transfer, and oxidative phosphorylation processes; and reducing mitochondrial reactive ROS production, which ultimately maintained mitochondrial membrane potential and ATP production in cardiomyocytes under hypoxic conditions. Notably, as a PPARγ agonist, pioglitazone promoted hypoxia-inducible factor 1α (HIF-1α) expression in hypoxic myocardium. Moreover, KC7F2, a HIF-1α inhibitor, disrupted the reprogramming of cardiac glucose metabolism and reduced cardiac function in pioglitazone-treated mice under hypoxic conditions. In conclusion, pioglitazone effectively prevented high-altitude hypoxia-induced cardiac dysfunction by reprogramming cardiac glucose metabolism.

IL-6 signaling accelerates iron overload by upregulating DMT1 in endothelial cells to promote aortic dissection.

Aortic dissection (AD), caused by tearing of the intima and avulsion of the aortic media, is a severe threat to patient life and organ function. Iron is closely related to dissection formation and organ injury, but the mechanism of iron ion transport disorder in endothelial cells (ECs) remains unclear. We identified the characteristic EC of dissection with iron overload by single-cell RNA sequencing data. After intersecting iron homeostasis and differentially expressed genes, it was found that hypoxia-inducible factor-1α (HIF-1α) and divalent metal transporter 1 (DMT1) are key genes for iron ion disorder. Subsequently, IL-6R was identified as an essential reason for the JAK-STAT activation, a classical iron regulation pathway, through further intersection and validation. In in vivo and in vitro, both high IL-6 receptor expression and elevated IL-6 levels promote JAK1-STAT3 phosphorylation, leading to increased HIF-1α protein levels. Elevated HIF-1α binds explicitly to the 5'-UTR sequence of the DMT1 gene and transcriptionally promotes DMT1 expression, thereby increasing Fe2+ accumulation and endoplasmic reticulum stress (ERS). Blocking IL-6R and free iron with deferoxamine and tocilizumab significantly prolonged survival and reduced aortic and organ damage in dissection mice. A comparison of perioperative data between AD patients and others revealed that high free iron, IL-6, and ERS levels are characteristics of AD patients and are correlated with prognosis. In conclusion, activated IL-6/JAK1/STAT3 signaling axis up-regulates DMT1 expression by increasing HIF-1α, thereby increasing intracellular Fe2+ accumulation and tissue injury, which suggests a potential therapeutic target for AD.

Enhanced tumor response to adoptive T cell therapy with PHD2/3-deficient CD8 T cells.

While adoptive cell therapy has shown success in hematological malignancies, its potential against solid tumors is hindered by an immunosuppressive tumor microenvironment (TME). In recent years, members of the hypoxia-inducible factor (HIF) family have gained recognition as important regulators of T-cell metabolism and function. The role of HIF signalling in activated CD8 T cell function in the context of adoptive cell transfer, however, has not been explored in full depth. Here we utilize CRISPR-Cas9 technology to delete prolyl hydroxylase domain-containing enzymes (PHD) 2 and 3, thereby stabilizing HIF-1 signalling, in CD8 T cells that have already undergone differentiation and activation, modelling the T cell phenotype utilized in clinical settings. We observe a significant boost in T-cell activation and effector functions following PHD2/3 deletion, which is dependent on HIF-1α, and is accompanied by an increased glycolytic flux. This improvement in CD8 T cell performance translates into an enhancement in tumor response to adoptive T cell therapy in mice, across various tumor models, even including those reported to be extremely resistant to immunotherapeutic interventions. These findings hold promise for advancing CD8 T-cell based therapies and overcoming the immune suppression barriers within challenging tumor microenvironments.

Time-resolved NMR detection of prolyl-hydroxylation in intrinsically disordered region of HIF-1α.

Prolyl-hydroxylation is an oxygen-dependent posttranslational modification (PTM) that is known to regulate fibril formation of collagenous proteins and modulate cellular expression of hypoxia-inducible factor (HIF) α subunits. However, our understanding of this important but relatively rare PTM has remained incomplete due to the lack of biophysical methodologies that can directly measure multiple prolyl-hydroxylation events within intrinsically disordered proteins. Here, we describe a real-time 13C-direct detection NMR-based assay for studying the hydroxylation of two evolutionarily conserved prolines (P402 and P564) simultaneously in the intrinsically disordered oxygen-dependent degradation domain of hypoxic-inducible factor 1α by exploiting the "proton-less" nature of prolines. We show unambiguously that P564 is rapidly hydroxylated in a time-resolved manner while P402 hydroxylation lags significantly behind that of P564. The differential hydroxylation rate was negligibly influenced by the binding affinity to prolyl-hydroxylase enzyme, but rather by the surrounding amino acid composition, particularly the conserved tyrosine residue at the +1 position to P564. These findings support the unanticipated notion that the evolutionarily conserved P402 seemingly has a minimal impact in normal oxygen-sensing pathway.

PHD2 safeguards modest mesendoderm development.

PHD2 is essential in modulating HIF-1α levels upon oxygen fluctuations. Hypoxia, a hallmark of uterus, and HIF-1α have recently emerged as opposing regulators of mesendoderm specification, suggesting a role for PHD2 therein. We found that PHD2 expression initially covered the epiblast and gradually receded from the primitive streak, which was identical to hypoxia and exclusive to HIF-1α. The investigations performed in mESCs, embryoids, and mouse embryos together demonstrated that PHD2 negatively regulated mesendoderm specification. Single-cell RNA sequencing revealed that PHD2 governed the transition from epiblast to mesendoderm. The downstream effect of PHD2 relied on the HIF-1α regulated Wnt/ß-catenin pathway, while it was regulated upstream by miR-429. In summary, our research highlights PHD2's essential role in mesendoderm specification and its interactions with hypoxia and HIF-1α.

Therapeutic effects of focused ultrasound on vulvar squamous intraepithelial lesions in rat.

OBJECTIVE: In this study, we established a Sprague-Dawley rat model of vulvar squamous intraepithelial lesions and investigated the impact of focused ultrasound on the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and mutant type p53 (mtp53) in the vulvar skin of rats with low-grade squamous intraepithelial lesions (LSIL). MATERIALS AND METHODS: The vulvar skin of 60 rats was treated with dimethylbenzanthracene (DMBA) and mechanical irritation three times a week for 14 weeks. Rats with LSIL were randomly allocated into the experimental group or the control group. The experimental group was treated with focused ultrasound, while the control group received sham treatment. RESULTS: After 14 weeks treatment of DMBA combined with mechanical irritation, LSIL were observed in 44 (73.33%) rats, and high-grade squamous intraepithelial lesions (HSIL) were observed in 14 (23.33%) rats. 90.91% (20/22) of rats showed normal pathology and 9.09% (2/22) of rats exhibited LSIL in the experimental group at four weeks after focused ultrasound treatment. 22.73% (5/22) of rats exhibited LSIL, 77.27% (17/22) of rats progressed to HSIL in the control group. Compared with the control-group rats, the levels of HIF-1α, VEGF and mtp53 were significantly decreased in experimental-group rats (p < 0.05). CONCLUSIONS: These results indicate that DMBA combined with mechanical irritation can induce vulvar squamous intraepithelial lesion in SD rats. Focused ultrasound can treat LSIL safely and effectively, prevent the progression of vulvar lesions, and improve the microenvironment of vulvar tissues by decreasing the localized expression of HIF-1α, VEGF, and mtp53 in rats.

Hypoxia and Foxn1 alter the proteomic signature of dermal fibroblasts to redirect scarless wound healing to scar-forming skin wound healing in Foxn1-/- mice.

BACKGROUND: Foxn1-/- deficient mice are a rare model of regenerative skin wound healing among mammals. In wounded skin, the transcription factor Foxn1 interacting with hypoxia-regulated factors affects re-epithelialization, epithelial-mesenchymal transition (EMT) and dermal white adipose tissue (dWAT) reestablishment and is thus a factor regulating scar-forming/reparative healing. Here, we hypothesized that transcriptional crosstalk between Foxn1 and Hif-1α controls the switch from scarless (regenerative) to scar-present (reparative) skin wound healing. To verify this hypothesis, we examined (i) the effect of hypoxia/normoxia and Foxn1 signalling on the proteomic signature of Foxn1-/- (regenerative) dermal fibroblasts (DFs) and then (ii) explored the effect of Hif-1α or Foxn1/Hif-1α introduced by a lentiviral (LV) delivery vector to injured skin of regenerative Foxn1-/- mice with particular attention to the remodelling phase of healing. RESULTS: We showed that hypoxic conditions and Foxn1 stimulation modified the proteome of Foxn1-/- DFs. Hypoxic conditions upregulated DF protein profiles, particularly those related to extracellular matrix (ECM) composition: plasminogen activator inhibitor-1 (Pai-1), Sdc4, Plod2, Plod1, Lox, Loxl2, Itga2, Vldlr, Ftl1, Vegfa, Hmox1, Fth1, and F3. We found that Pai-1 was stimulated by hypoxic conditions in regenerative Foxn1-/- DFs but was released by DFs to the culture media exclusively upon hypoxia and Foxn1 stimulation. We also found higher levels of Pai-1 protein in DFs isolated from Foxn1+/+ mice (reparative/scar-forming) than in DFs isolated from Foxn1-/- (regenerative/scarless) mice and triggered by injury increase in Foxn1 and Pai-1 protein in the skin of mice with active Foxn1 (Foxn1+/+ mice). Then, we demonstrated that the introduction of Foxn1 and Hif-1α via lentiviral injection into the wounded skin of regenerative Foxn1-/- mice activates reparative/scar-forming healing by increasing the wounded skin area and decreasing hyaluronic acid deposition and the collagen type III to I ratio. We also identified a stimulatory effect of LV-Foxn1 + LV-Hif-1α injection in the wounded skin of Foxn1-/- mice on Pai-1 protein levels. CONCLUSIONS: The present data highlight the effect of hypoxia and Foxn1 on the protein profile and functionality of regenerative Foxn1-/- DFs and demonstrate that the introduction of Foxn1 and Hif-1α into the wounded skin of regenerative Foxn1-/- mice activates reparative/scar-forming healing.

Evaluation of SBDP145, melatonin, sLOX-1, HMGB1 and HIF-1α in preterm infants with brain injury.

BACKGROUND: Prematurity-related brain injury is a common and serious complication that has long-term effects on the survival and development of affected infants. Currently, the roles of certain biomarkers such as the protein hydrolysis product SBDP145, melatonin, soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1), high mobility group box 1 protein (HMGB1), and hypoxia-inducible factor 1-alpha (HIF-1α) in prematurity-related brain injury remain not fully elucidated. Our study aims to assess the significance of SBDP145, melatonin, sLOX-1, HMGB1 and HIF-1α in preterm infants with brain injury. METHODS: 135 preterm infants admitted to our hospital from January 2020 to February 2022 were selected and divided into 78 cases in a prematurity-associated brain injury group, and 57 cases in another group of preterm infants without brain injury or other diseases according to the magnetic resonance imaging results. The levels of SBDP145, melatonin, sLOX-1, HMGB1 and HIF-1α in the two groups were analyzed. The serum concentrations of SBDP145, melatonin, sLOX-1, HMGB1 and HIF-1α in newborns with different severity of ventricular hemorrhage were observed, and the levels of SBDP145, melatonin, sLOX-1, HMGB1 and HIF-1α in those with different severity of white matter brain injury were compared. RESULTS: The levels of SBDP145, sLOX-1, HMGB1 and HIF-1α were significantly higher in the preterm combined brain injury group than in the preterm group, and melatonin levels were significantly lower than in the preterm group(P < 0.05). The levels of SBDP145, sLOX-1, HMGB1 and HIF-1α were higher in the moderate to severe group and melatonin levels were lower in the mild group of newborns with ventricular hemorrhage (P < 0.05). The levels of SBDP145, sLOX-1, HMGB1 and HIF-1α were higher in the moderate-severe group and melatonin levels were lower in the mild group in newborns with cerebral white matter injury (P < 0.05). The independent variables were SBDP145, melatonin, sLOX-1, HMGB1, HIF-1α, and the dependent variable was the prognosis of neonates with brain injury. Univariate logistic regression analysis and multivariate logistic regression analysis were performed. The results showed that the influencing factors of newborns with brain injury were SBDP145, melatonin, sLOX-1, HMGB1, HIF-1α. CONCLUSION: The levels of SBDP145, melatonin, sLOX-1, HMGB1 and HIF-1α were highly expressed in preterm newborns with brain injury, and the levels were higher when the condition of the newborns was more severe. These findings suggest the potential clinical utility of these biomarkers in predicting and monitoring brain injury in preterm infants, which could aid in early intervention and improve long-term outcomes.

Inhibited hypoxia-inducible factor by intraoperative hyperglycemia increased postoperative delirium of aged patients: A review.

The underlying mechanism of postoperative delirium (POD) in elderly people remains unclear. Perioperative hyperglycemia (POHG) is an independent risk indicator for POD, particularly in the elderly. Under cerebral desaturation (hypoxia) during general anesthesia, hypoxia-inducible factor (HIF) is neuroprotective during cerebral hypoxia via diverse pathways, like glucose metabolism and angiogenesis. Hyperglycemia can repress HIF expression and activity. On the other hand, POHG occurred among patients undergoing surgery. For surgical stress, hypothalamic-pituitary-adrenal activation and sympathoadrenal activation may increase endogenous glucose production via gluconeogenesis and glycogenolysis. Thus, under the setting of cerebral hypoxia during general anesthesia, we speculate that POHG prevents HIF-1α levels and function in the brain of aged patients, thus exacerbating the hypoxic response of HIF-1 and potentially contributing to POD. This paper sketches the underlying mechanisms of HIF in POD in elderly patients and offers novel insights into targets for preventing or treating POD in the same way as POHG.

Hypoxia activates macrophage-NLRP3 inflammasome promoting atherosclerosis via PFKFB3-driven glycolysis.

The onset and progression of atherosclerosis are closely linked to the involvement of macrophages. While the contribution of NLRP3 inflammasome activation to the creation of a local highly inflammatory microenvironment is well recognized, the precise triggers remain unclear. In this study, we aimed to investigate the regulatory mechanism of NLRP3 inflammasome activation in response to hypoxia-induced glycolysis involving PFKFB3 in the development of atherosclerosis. To develop an atherosclerosis model, we selected ApoE knockout mice treated with a high-fat western diet. We then quantified the expression of HIF-1α, PFKFB3, and NLRP3. In addition, we administered the PFKFB3 inhibitor PFK158 during atherosclerosis modeling. The glycolytic activity was subsequently determined through 18F-FDG micro-PET/CT, ex vivo glucose uptake, and ECAR analysis. Furthermore, we employed lipopolysaccharide (LPS) and TNF-α to induce the differentiation of bone marrow-derived macrophages (BMDMs) into M1-like phenotypes under both hypoxic and normoxic conditions. Our histological analyses revealed the accumulation of PFKFB3 in human atherosclerotic plaques, demonstrating colocalization with NLRP3 expression and macrophages. Treatment with PFK158 reduced glycolytic activity and NLRP3 inflammasome activation, thereby mitigating the occurrence of atherosclerosis. Mechanistically, hypoxia promoted glycolytic reprogramming and NLRP3 inflammasome activation in BMDMs. Subsequent blocking of either HIF-1α or PFKFB3 downregulated the NLRP3/Caspase-1/IL-1ß pathway in hypoxic BMDMs. Our study demonstrated that the HIF-1α/PFKFB3/NLRP3 axis serves as a crucial mechanism for macrophage inflammation activation in the emergence of atherosclerosis. The therapeutic potential of PFKFB3 inhibition may represent a promising strategy for atheroprotection.

Hypoxia-inducible factor-1α can reverse the Adriamycin resistance of breast cancer adjuvant chemotherapy by upregulating transferrin receptor and activating ferroptosis.

Breast cancer is a common malignant tumor in women. Ferroptosis, a programmed cell death pathway, is closely associated with breast cancer and its resistance. The transferrin receptor (TFRC) is a key factor in ferroptosis, playing a crucial role in intracellular iron accumulation and the occurrence of ferroptosis. This study investigates the influence and significance of TFRC and its upstream transcription factor hypoxia-inducible factor-1α (HIF1α) on the efficacy of neoadjuvant therapy in breast cancer. The differential gene obtained from clinical samples through genetic sequencing is TFRC. Bioinformatics analysis revealed that TFRC expression in breast cancer was significantly greater in breast cancer tissues than in normal tissues, but significantly downregulated in Adriamycin (ADR)-resistant tissues. Iron-responsive element-binding protein 2 (IREB2) interacts with TFRC and participates in ferroptosis. HIF1α, an upstream transcription factor, positively regulates TFRC. Experimental results indicated higher levels of ferroptosis markers in breast cancer tissue than in normal tissue. In the TAC neoadjuvant regimen-sensitive group, iron ion (Fe2+) and malondialdehyde (MDA) levels were greater than those in the resistant group (all p < .05). Expression levels of TFRC, IREB2, FTH1, and HIF1α were higher in breast cancer tissue compared to normal tissue. Additionally, the expression of the TFRC protein in the TAC neoadjuvant regimen-sensitive group was significantly higher than that in the resistant group (all p < .05), while the difference in the level of expression of IREB2 and FTH1 between the sensitive and resistant groups was not significant (p > .05). The dual-luciferase assay revealed that HIF1α acts as an upstream transcription factor of TFRC (p < .05). Overexpression of HIF1α in ADR-resistant breast cancer cells increased TFRC, Fe2+, and MDA content. After ADR treatment, the cell survival rate decreased significantly, and ferroptosis could be reversed by the combined application of Fer-1 (all p < .05). In conclusion, ferroptosis and chemotherapy resistance are correlated in breast cancer. TFRC is a key regulatory factor influenced by HIF1α and is associated with chemotherapy resistance. Upregulating HIF1α in resistant cells may reverse resistance by activating ferroptosis through TFRC overexpression.

Oral administration of Robinia pseudoacacia L. flower exosome-like nanoparticles attenuates gastric and small intestinal mucosal ferroptosis caused by hypoxia through inhibiting HIF-1α- and HIF-2α-mediated lipid peroxidation.

The prevention and treatment of gastrointestinal mucosal injury caused by a plateau hypoxic environment is a clinical conundrum due to the unclear mechanism of this syndrome; however, oxidative stress and microbiota dysbiosis may be involved. The Robinia pseudoacacia L. flower, homologous to a functional food, exhibits various pharmacological effects, such as antioxidant, antibacterial, and hemostatic activities. An increasing number of studies have revealed that plant exosome-like nanoparticles (PELNs) can improve the intestinal microbiota and exert antioxidant effects. In this study, the oral administration of Robinia pseudoacacia L. flower exosome-like nanoparticles (RFELNs) significantly ameliorated hypoxia-induced gastric and small intestinal mucosal injury in mice by downregulating hypoxia-inducible factor-1α (HIF-1α) and HIF-2α expression and inhibiting hypoxia-mediated ferroptosis. In addition, oral RFELNs partially improved hypoxia-induced microbial and metabolic disorders of the stomach and small intestine. Notably, RFELNs displayed specific targeting to the gastrointestinal tract. In vitro experiments using gastric and small intestinal epithelial cell lines showed that cell death caused by elevated HIF-1α and HIF-2α under 1% O2 mainly occurred via ferroptosis. RFELNs obviously inhibited HIF-1α and HIF-2α expression and downregulated the expression of NOX4 and ALOX5, which drive reactive oxygen species production and lipid peroxidation, respectively, suppressing ferroptosis under hypoxia. In conclusion, our findings underscore the potential of oral RFELNs as novel, naturally derived agents targeting the gastrointestinal tract, providing a promising therapeutic approach for hypoxia-induced gastric and small intestinal mucosal ferroptosis.

Hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway-based ulcer-healing mechanism of Astragalus Aqueous extract in diabetic foot rats.

The main objective of this work was to investigate the mechanism of Astragalus aqueous extract ulcer healing in diabetic foot model rats through the hypoxia-inducible factor 1-alpha (HIF-1ɑ)/vascular endothelial growth factor (VEGF) signalling pathway. Fifty specific-pathogen-free male Sprague Dawley rats were divided into blank (A), model control (B), Astragalus extract (C) and mupirocin (D) treatment groups. Group A received a regular diet, whereas the other groups received a high-fat/high-sugar diet and intraperitoneal streptozotocin injections to induce diabetes. Diabetic foot ulcers were created via skin excision. Subsequently, ulcers were debrided daily. Groups B, C and D received wet saline gauze, wet gauze with Astragalus extract and gauze with mupirocin, respectively, on the affected area. Group A received no treatment. After 14 days, the rats were assessed for ulcer healing and general condition. Immunohistochemistry was used to detect HIF-1ɑ and VEGF levels in the dorsalis pedis artery, and ELISA was used to determine serum IL-6 and CRP levels. The results revealed that Groups C and D had significantly faster ulcer healing compared with Group B (p < 0.01), and ulcer healing was faster in Group C than in Group D (p < 0.01). Group C exhibited notably higher HIF-1ɑ and VEGF protein expression levels compared with Groups B and D (p < 0.01). IL-6 and CRP expression levels in Groups C and D were significantly lower than those in Group B (p < 0.01). In summary, Astragalus aqueous extract effectively treats diabetic foot ulcers by up-regulating HIF-1ɑ and VEGF expression, activating the HIF-1ɑ/VEGF pathway, improving local tissue ischaemia and hypoxia, promoting collateral circulation and enhancing dorsalis pedis artery formation, thereby accelerating ulcer repair in diabetic rats.

Bufalin-Loaded Multifunctional Photothermal Nanoparticles Inhibit the Anaerobic Glycolysis by Targeting SRC-3/HIF-1α Pathway for Improved Mild Photothermal Therapy in CRC.

Purpose: Compared with traditional photothermal therapy (PTT, >50°C), mild PTT (≤45°C) is a promising strategy for tumor therapy with fewer adverse effects. Unfortunately, its anti-tumor efficacy is hampered by thermoresistance induced by overexpression of heat shock proteins (HSPs). In our previous study, we found bufalin (BU) is a glycolysis inhibitor that depletes HSPs, which is expected to overcome thermotolerance of tumor cells. In this study, BU-loaded multifunctional nanoparticles (NPs) were developed for enhancing the mild PTT of colorectal cancer (CRC). Methods: Fe3O4 NPs coated with the polydopamine (PDA) shell modified with polyethylene glycol (PEG) and cyclic arginine-glycyl-aspartic peptide (cRGD) for loading BU (Fe3O4@PDA-PEG-cRGD/BU NPs) were developed. The thermal variations in Fe3O4@PDA-PEG-cRGD/BU NPs solution under different conditions were measured. Glycolysis inhibition was evaluated by measuring the glucose uptake, extracellular lactate, and intracellular adenosine triphosphate (ATP) levels. The cellular cytotoxicity of Fe3O4@PDA-PEG-cRGD/BU NPs was analyzed using a cell counting kit-8 assay, Calcein-AM/PI double staining, and flow cytometry in HCT116 cells. The magnetic resonance imaging (MRI) performance and anti-tumor therapeutic efficacy of Fe3O4@PDA-PEG-cRGD/BU NPs were evaluated in HCT116-tumor bearing mice. Results: Fe3O4@PDA-PEG-cRGD/BU NPs had an average diameter of 260.4±3.5 nm, the zeta potential of -23.8±1.6 mV, the drug loading rate of 1.1%, which had good thermal stability, photothermal conversion efficiencies and MRI performance. In addition, the released BU not only killed tumor cells but also interfered with glycolysis by targeting the steroid receptor coactivator 3 (SRC-3)/HIF-1α pathway, preventing intracellular ATP synthesis, and combating HSP-dependent tumor thermoresistance, ultimately strengthening the thermal sensitivity toward mild PTT both in vitro and in vivo. Conclusion: This study provides a highly effective strategy for enhancing the therapeutic effects of mild PTT toward tumors.

Catalpol attenuates hepatic glucose metabolism disorder and oxidative stress in triptolide-induced liver injury by regulating the SIRT1/HIF-1α pathway.

Triptolide (TP), known for its effectiveness in treating various rheumatoid diseases, is also associated with significant hepatotoxicity risks. This study explored Catalpol (CAT), an iridoid glycoside with antioxidative and anti-inflammatory effects, as a potential defense against TP-induced liver damage. In vivo and in vitro models of liver injury were established using TP in combination with different concentrations of CAT. Metabolomics analyses were conducted to assess energy metabolism in mouse livers. Additionally, a Seahorse XF Analyzer was employed to measure glycolysis rate, mitochondrial respiratory functionality, and real-time ATP generation rate in AML12 cells. The study also examined the expression of proteins related to glycogenolysis and gluconeogenesis. Using both in vitro SIRT1 knockout/overexpression and in vivo liver-specific SIRT1 knockout models, we confirmed SIRT1 as a mechanism of action for CAT. Our findings revealed that CAT could alleviate TP-induced liver injury by activating SIRT1, which inhibited lysine acetylation of hypoxia-inducible factor-1α (HIF-1α), thereby restoring the balance between glycolysis and oxidative phosphorylation. This action improved mitochondrial dysfunction and reduced glucose metabolism disorder and oxidative stress caused by TP. Taken together, these insights unveil a hitherto undocumented mechanism by which CAT ameliorates TP-induced liver injury, positioning it as a potential therapeutic agent for managing TP-induced hepatotoxicity.