Hypoxia-inducible Factor Research Articles

Identification of stimuli that enhance human herpesvirus 6A (HHV-6A) replication and reconstitution

ABSTRACT Despite the availability of bacterial artificial chromosome (BAC) systems for human herpesvirus 6A (HHV-6A), reconstitution of infectious viruses is very challenging and time consuming. In this study, we developed approaches to improve the reconstitution process and enhance virus replication to overcome these technical challenges. Using dimethyl sulfoxide and exonuclease V, we significantly increased the efficiency of BAC transfections into JJHan T cells. We tested several stimulation strategies to enhance lytic replication and identified mitogens and glucocorticoids that, in combination, improve virus replication. In addition, we demonstrated that the interferon-mediated response impairs virus reconstitution and that the JAK1/JAK2 inhibitor ruxolitinib resulted in an immense improvement. Furthermore, hypoxia-inducible factor 1 alpha stabilization by IOX2 drastically accelerated virus reconstitution, indicating that the hypoxic response is a crucial regulator of HHV-6A replication. Our study sheds light on strategic approaches that improve replication and reconstitution of this ubiquitous human herpesvirus. IMPORTANCE HHV-6A is a betaherpesvirus that infects a wide range of human tissues and establishes lifelong latency in the host. Its reactivation has been implicated in several diseases, including multiple sclerosis, encephalitis, myocarditis, and chronic fatigue syndrome, although its pathogenetic role remains elusive. The efficacy of common antiviral drugs is limited, and no specific drugs target HHV-6A infection. The data of this study shed light on stimuli and potential pathways that influence HHV-6A replication and reconstitution. Our strategies not only simplify virus propagation and reconstitution to study HHV-6A biology but also provide the basis for the development of therapeutic strategies.

Pentoxifylline improves anemia through its novel effect on hypoxia-inducible factor-2 alpha in hemodialysis patients: a randomized, double-blind, placebo-controlled clinical trial

ABSTRACT Objectives This randomized, double-blind, placebo-controlled clinical trial aimed to prospectively examine the effect of pentoxifylline (PTX) on hypoxia-inducible factor-2 alpha (HIF-2α) and its role in controlling anemia in hemodialysis (HD) patients. Methods Eighty patients on HD were randomized to receive 400 mg of PTX or placebo twice daily for 6 months. The hemoglobin (Hb) and other hematologic parameters, the weekly erythropoiesis-stimulating agents (ESAs), and the ESA resistance index (ERI) were assessed monthly during the study. The HIF-2α, transforming growth factor-β1 (TGF-β1), and high-sensitivity C-reactive protein (hs.CRP) were measured before and after the intervention. Results In the pentoxifylline group, an appreciable increase in Hb from 9.7 (9.3, 10.3) g/dl to 10.5 (9.3, 11.4) g/dl and hematocrit (Hct) from 31.3 (29.6, 32.4)% to 33.2 (29.4, 35.9)% was observed after one month of PTX administration, and this effect was maintained over the study time (p < 0.001). This was along with a decrease in the ESA doses required from 8000 (8000, 11500) IU/wk to 4000 (2000, 8000) IU/wk (p < 0.001), and an improvement in the ERI from 11.6 (8.07, 16.97) IU/kg/wk/g/dl to 5.79 (2.01, 10.09) IU/kg/wk/g/dl (p < 0.001). Additionally, the HIF-2α increased significantly at the end of the intervention in patients who received PTX from 3245.35 (2886.8, 4691.56) pg/ml to 7208.75 (5382, 9182.7) pg/ml, while TGF-β1 and hs.CRP decreased significantly from 657.78 (539.78, 1146.62) pg/ml and 88.08 (39.93, 100.4) mg/l to 329.94 (228.67, 793.18) pg/ml and 48.65 (34.44, 84.61) mg/l, respectively. The percent changes in HIF-2α, TGF-β1, and hs.CRP levels in the pentoxifylline group were also statistically significant in comparison with the placebo group. Conclusions PTX could be a promising agent for correcting anemia in HD patients via increasing HIF-2α levels. Clinical trial registration Clinicaltrials.gov, February 2023, registry number: NCT05708248.

Prognostic Significance of Microvessel Density and Hypoxic Markers in Canine Osteosarcoma: Insights into Angiogenesis and Tumor Aggressiveness

Canine osteosarcoma (OSA) is an aggressive and highly malignant tumor of bone with a poor prognosis and it mirrors the disease in humans. Angiogenesis, the formation of new blood vessels, is driven by hypoxia-induced factors such as HIF-1α and VEGF, both of which play a crucial role in tumor growth and metastasis. However, the role of angiogenesis in OSA remains a topic of ongoing debate. This study aimed to investigate the relationship between angiogenesis, measured by intratumoral microvessel density (MVD), hypoxic markers, and clinical outcomes in 28 dogs diagnosed with appendicular OSA. Clinicopathological data such as age, breed distribution, tumor localization, histopathological subtypes, and metastatic behavior were consistent with reported epidemiologic characteristics of canine OSA, though no significant correlation was found among these variables. The results indicated a significant association between higher MVD and high-grade OSA (p = 0.029), suggesting that increased tumor vascularization is linked to more aggressive tumor behavior. Additionally, elevated VEGF expression was strongly correlated with disease-free interval DFI), with a p-value of 0.045. Although HIF-1α positivity showed a trend towards poorer survival, the results did not reach statistical significance (p = 0.07). These findings highlight the potential role of VEGF as a valuable prognostic marker in canine OSA, which could have potentially important implications for therapeutic targeting and clinical management of the disease. This study advances the understanding of angiogenesis in canine OSA, while emphasizing the need for continued research into the complex mechanisms regulating the interplay between hypoxia, angiogenesis and tumor progression.

Microvascular insulin resistance with enhanced muscle glucose disposal in CD36 deficiency.

Microvascular dysfunction contributes to insulin resistance. CD36, a fatty acid transporter and modulator of insulin signalling, is abundant in microvascular endothelial cells. Humans carrying the minor allele (G) of CD36 coding variant rs3211938 have 50% reduced CD36 expression and show endothelial dysfunction. We aimed to determine whether G allele carriers have microvascular resistance to insulin and, if so, how this affects glucose disposal. Our multi-disciplinary approach included hyperinsulinaemic-euglycaemic clamps in Cd36-/- and wild-type mice, and in individuals with 50% CD36 deficiency, together with control counterparts, in addition to primary human-derived microvascular endothelial cells with/without CD36 depletion. Insulin clamps showed that Cd36-/- mice have enhanced insulin-stimulated glucose disposal but reduced vascular compliance and capillary perfusion. Intravital microscopy of the gastrocnemius showed unaltered transcapillary insulin flux. CD36-deficient humans had better insulin-stimulated glucose disposal but insulin-unresponsive microvascular blood volume (MBV). Human microvascular cells depleted of CD36 showed impaired insulin activation of Akt, endothelial NO synthase and NO generation. Thus, in CD36 deficiency, microvascular insulin resistance paradoxically associated with enhanced insulin sensitivity of glucose disposal. CD36 deficiency was previously shown to reduce muscle/heart fatty acid uptake, whereas here we showed that it reduced vascular compliance and the ability of insulin to increase MBV for optimising glucose and oxygen delivery. The muscle and heart respond to these energy challenges by transcriptional remodelling priming the tissue for insulin-stimulated glycolytic flux. Reduced oxygen delivery activating hypoxia-induced factors, endothelial release of growth factors or small intracellular vesicles might mediate this adaptation. Targeting NO bioavailability in CD36 deficiency could benefit the microvasculature and muscle/heart metabolism. Clinicaltrials.gov NCT03012386 DATA AVAILABILITY: The RNAseq data generated in this study have been deposited in the NCBI Gene Expression Omnibus ( www.ncbi.nlm.nih.gov/geo/ ) under accession code GSE235988 ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE235988 ).

Etrinabdione (VCE-004.8), a B55α activator, promotes angiogenesis and arteriogenesis in critical limb ischemia.

Vasculogenic therapies explored for the treatment of peripheral artery disease (PAD) have encountered minimal success in clinical trials. Addressing this, B55α, an isoform of protein phosphatase 2A (PP2A), emerges as pivotal in vessel remodeling through activation of hypoxia-inducible factor 1α (HIF-1α). This study delves into the pharmacological profile of VCE-004.8 (Etrinabdione) and evaluates its efficacy in a preclinical model of critical limb ischemia, with a focus on its potential as a PP2A/B55α activator to induce angiogenesis and arteriogenesis. Vascular endothelial cells were used for in vitro experiments. Aorta ring assay was performed to explore sprouting activity. Matrigel plug-in assay was used to assess the angiogenic potential. Critical limb ischemia (CLI) in mice was induced by double ligation in the femoral arteria. Endothelial vascular and fibrotic biomarkers were studied by immunohistochemistry and qPCR. Arteriogenesis was investigated by microvascular casting and micro-CT. Proteomic analysis in vascular tissues was analyzed by LC-MS/MS. Ex-vivo expression of B55α and biomarkers were investigated in artery samples from PAD patients. VCE-004.8 exhibited the ability to induce B55α expression and activate the intersecting pathways B55α/AMPK/Sirtuin 1/eNOS and B55α/PHD2/HIF-1α. VCE-004.8 prevented OxLDL and H2O2-induced cytotoxicity, senescence, and inflammation in endothelial cells. Oral VCE-004.8 increased aorta sprouting in vitro and angiogenesis in vivo. In CLI mice VCE-004.8 improved collateral vessel formation and induced endothelial cells proliferation, angiogenic gene expression and prevented fibrosis. The expression of B55α, Caveolin 1 and Sirtuin-1 is reduced in arteries from CLI mice and PAD patient, and the expression of these markers was restored in mice treated with VCE-004.8. The findings presented in this study indicate that Etrinabdione holds promise in mitigating endothelial cell damage and senescence, while concurrently fostering arteriogenesis and angiogenesis. These observations position Etrinabdione as a compelling candidate for the treatment of PAD, and potentially other cardiovascular disorders.

VEGF inhibition increases expression of HIF-regulated angiogenic genes by the RPE limiting the response of wet AMD eyes to aflibercept

Neovascular age-related macular degeneration (nvAMD) is the leading cause of severe vision loss in the elderly in the developed world. While the introduction of therapies targeting vascular endothelial growth factor (VEGF) has provided the first opportunity to significantly improve vision in patients with nvAMD, many patients respond inadequately to current anti-VEGF therapies. It was recently demonstrated that expression of a second angiogenic mediator, angiopoietin-like 4 (ANGPTL4), synergizes with VEGF to promote choroidal neovascularization (CNV) in mice and correlates with reduced response to anti-VEGF therapy in patients with nvAMD. Here, we report that expression of ANGPTL4 in patients with nvAMD increases following treatment with anti-VEGF therapy and that this increase is dependent on accumulation of hypoxia-inducible factor (HIF)-1α in response to inhibition of VEGF/KDR signaling in the retinal pigment epithelium (RPE). We therefore explored HIF-1 inhibition with 32-134D, a recently developed pharmacologic HIF-inhibitor, for the treatment of nvAMD. 32-134D prevented the expression of both VEGF and ANGPTL4 and was at least as effective as aflibercept in treating CNV in mice. Moreover, by preventing the increase in HIF-1α accumulation in the RPE in response to anti-VEGF therapy, combining 32-134D with aflibercept was more effective than either drug alone for the treatment of CNV. Collectively, these results help explain why many patients with nvAMD respond inadequately to anti-VEGF therapy and suggest that the HIF inhibitor 32-134D will be an effective drug-alone or in combination with current anti-VEGF therapies-for the treatment of patients with this blinding disease.

Molecular and Cellular Mechanisms Involved in the Pathophysiology of Retinal Vascular Disease—Interplay Between Inflammation and Oxidative Stress

Retinal vascular diseases encompass several retinal disorders, including diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, and retinal vascular occlusion; these disorders are classified as similar groups of disorders due to impaired retinal vascularization. The aim of this review is to address the main signaling pathways involved in the pathogenesis of retinal vascular diseases and to identify crucial molecules and the importance of their interactions. Vascular endothelial growth factor (VEGF) is recognized as a crucial and central molecule in abnormal neovascularization and a key phenomenon in retinal vascular occlusion; thus, anti-VEGF therapy is now the most successful form of treatment for these disorders. Interaction between angiopoietin 2 and the Tie2 receptor results in aberrant Tie2 signaling, resulting in loss of pericytes, neovascularization, and inflammation. Notch signaling and hypoxia-inducible factors in ischemic conditions induce pathological neovascularization and disruption of the blood–retina barrier. An increase in the pro-inflammatory cytokines—TNF-α, IL-1β, and IL-6—and activation of microglia create a persistent inflammatory milieu that promotes breakage of the blood–retinal barrier and neovascularization. Toll-like receptor signaling and nuclear factor-kappa B are important factors in the dysregulation of the immune response in retinal vascular diseases. Increased production of reactive oxygen species and oxidative damage follow inflammation and together create a vicious cycle because each factor amplifies the other. Understanding the complex interplay among various signaling pathways, signaling cascades, and molecules enables the development of new and more successful therapeutic options.

Atypical chemokine receptor 2 expression is directly regulated by hypoxia inducible factor-1 alpha in cancer cells under hypoxia

Lack of significant and durable clinical benefit from anti-cancer immunotherapies is partly due to the failure of cytotoxic immune cells to infiltrate the tumor microenvironment. Immune infiltration is predominantly dependent on the chemokine network, which is regulated in part by chemokine and atypical chemokine receptors. We investigated the impact of hypoxia in the regulation of Atypical Chemokine Receptor 2 (ACKR2), which subsequently regulates major pro-inflammatory chemokines reported to drive cytotoxic immune cells into the tumor microenvironment. Our in silico analysis showed that both murine and human ACKR2 promoters contain hypoxia response element (HRE) motifs. Murine and human colorectal, melanoma, and breast cancer cells overexpressed ACKR2 under hypoxic conditions in a HIF-1α dependent manner; as such overexpression was abrogated in melanoma cells expressing non-functional deleted HIF-1α. We also showed that decreased expression of ACKR2 in HIF-1α-deleted cells under hypoxia was associated with increased CCL5 levels. Chromatin immunoprecipitation data confirmed that ACKR2 is directly regulated by HIF-1α at its promoter in B16-F10 melanoma cells. This study provides new key elements on how hypoxia can impair immune infiltration in the tumor microenvironment.

Triggered Cascade-Activation Nanoplatform to Alleviate Hypoxia for Effective Tumor Immunotherapy Guided by NIR-II Imaging.

Hypoxia is one of the most typical features among various types of solid tumors, which creates an immunosuppressive tumor microenvironment (TME) and limits the efficacy of cancer treatment. Alleviating hypoxia becomes a key strategy to reshape hypoxic TME which improves cancer immunotherapy. However, it remains challenging to perform tumor precision therapy with controllable switches through hypoxia-activated gene editing and prodrugs to alleviate hypoxia. In this study, silica-coated second near-infrared window (NIR-II) emitting silver sulfide quantum dots are used as the carrier to load the Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 (CRISPR/Cas9) system to target hypoxia-inducible factor-1 (HIF-1α) and guide tumor-targeted imaging. To reduce the off-target effects in nontumor cells and better control safety risks, a TME-triggered cascade-activation nanodiagnostic and therapeutic platform (AA@Cas-H@HTS) is designed, which achieves the hypoxia activation of prodrug tirapazamine (TPZ) and spatiotemporal release of CRISPR/Cas9 ribonucleoprotein. Tumor hypoxia is greatly alleviated by the synergistic function of HIF-1α depletion by gene editing and TPZ activation. Importantly, targeting HIF-1α disrupts the programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) signaling pathway, which effectively reshapes the immune-suppressive TME and activates T cell-mediated antitumor immunity. Taken together, we have provided a TME-triggered cascade-activation nanoplatform to alleviate hypoxia for improved cancer immunotherapy.

Hypertension Induced by Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors in Treating Anemia in Patients With Chronic Kidney Disease: A Mini-Review.

Hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitors are a new class of agents for the treatment of anemia in chronic kidney disease (CKD). Unlike traditional treatments such as erythropoiesis-stimulating agents (ESAs), HIF-PH inhibitors are orally administered drugs and may increase endogenous erythropoietin and improve iron homeostasis. However, a significant concern is their possible side effect on blood pressure. The current mini-review summarizes the data of 26 randomized controlled (placebo or ESAs) trials on six different HIF-PH inhibitors with regard to their potential influence on blood pressure and hypertension in the management of anemia in CKD. Overall, the use of HIF-PH inhibitors was associated with a higher risk of hypertension than placebo (pooled risk ratio 1.36, 95% confidence interval [CI] 1.16-1.59), but a lower risk of hypertension than ESA treatment (pooled risk ratio 0.92, 95% CI 0.86-0.98), especially in CKD patients not undergoing dialysis (pooled risk ratio 0.85, 95% CI 0.73-0.98). This review highlights the importance of blood pressure monitoring during the treatment of HIF-PH inhibitors, especially out-of-office blood pressure measurement.

Hypoxic Responses in Periodontal Tissues: Influence of Smoking and Periodontitis.

This study aimed to investigate the hypoxic changes in periodontal tissues resulting from smoking and periodontitis by assessing levels of hypoxia-inducible factors (HIF-1α, HIF-2α, HIF-3α) and vascular endothelial growth factor (VEGF) in gingival crevicular fluid (GCF). The study comprised 22 periodontally healthy non-smokers (Group H), 22 periodontally healthy smokers (Group HS), 22 non-smokers with periodontitis (Group P) and 22 smokers with periodontitis (Group PS). Clinical periodontal parameters were documented, and GCF samples were collected and analysed using enzyme-linked immunosorbent assay (ELISA). Significantly elevated levels of HIF-1α, HIF-3α and VEGF were observed in Groups HS, P and PS compared to Group H (p < 0.05). Moreover, higher HIF-2α levels were detected in the Groups HS and P compared to Group H (p < 0.05). Significant correlations were detected between all evaluated hypoxia biomarkers in the Group P (p < 0.05) except HIF-2α and HIF-3α. However, in the PS group, significant correlation appeared only between HIF-1α and HIF-2α (p < 0.05). Our findings indicate that smoking and periodontitis induce comparable hypoxic effects in periodontal tissues, as evidenced by the evaluated biomarkers. Further research is warranted to gain a deeper understanding of the mechanisms underlying hypoxia in periodontal tissues.

Influenza A virus-induced glycolysis facilitates virus replication by activating ROS/HIF-1α pathway

As a highly contagious acute respiratory disease, influenza A virus (A/WSN/1933) poses a huge threat to human health and public health. influenza A virus proliferation relies on glucose metabolism in host cells, yet the effects of influenza A virus on glucose metabolism and the underlying molecular mechanisms remain unclear. Here, we created models of WSN virus-infected mice and A549 cells, along with analyzing metabolomics and transcriptomics data, to investigate how WSN virus infection affects host cell glucose metabolism and specific mechanisms. Analysis of metabolites and gene expression showed that WSN virus infection triggers glycolysis in A549 cells, with notable upregulation of hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), hypoxia-inducible factor-1 alpha (HIF-1α), and elevated lactate levels. Additionally, it leads to mitochondrial impairment and heightened reactive oxygen species (ROS) generation. Elevated levels of glucose may enhance the replication of WSN virus, whereas inhibitors of glycolysis can reduce it. Enhancement of HIF-1α activation facilitated replication of WSN virus through stimulation of lactate synthesis, with the primary influence of glycolysis on WSN virus replication being mediated by ROS/HIF-1α signaling. Mice given HIF-1α inhibitor PTX-478 or glycolysis inhibitor 2-Deoxyglucose (2-DG) exhibited reduced lactate levels and decreased WSN virus replication, along with mitigated weight loss and lung damage. In summary, WSN virus-induced glycolysis has been demonstrated to enhance virus replication through the activation of the ROS/HIF-1α pathway, suggesting potential new targets for combating the virus.

PDGFRB promotes dedifferentiation and pulmonary metastasis through rearrangement of cytoskeleton under hypoxic microenvironment in osteosarcoma

BackgroundOsteosarcoma (OS) cells commonly suffer from hypoxia and dedifferentiation, resulting in poor prognosis. We plan to identify the role of hypoxia on dedifferentiation and the associated cellular signaling. MethodsWe performed sphere formation assays and determined spheroid cells as dedifferentiated cells by detecting stem cell-like markers. RNAi assay was used to explore the relationship between hypoxia inducible factor 1 subunit alpha (HIF1A) and platelet derived growth factor receptor beta (PDGFRB). We obtained PDGFRB knockdown and overexpression cells through lentiviral infection experiments and detected the expression of PDGFRB, p-PDGFRB, focal adhesion kinase (FAK), p-FAK, phosphorylated myosin light chain 2 (p-MLC2), and ras homolog family member A (RhoA) in each group. The effects of PDGFRB on cytoskeleton rearrangement and cell adhesion were explored by immunocytochemistry. Wound-healing experiments, transwell assays, and animal trials were employed to investigate the effect of PDGFRB on OS cell metastasis both in vitro and in vivo. ResultsDedifferentiated OS cells were found to exhibit high expression of HIF1A and PDGFRB, and HIF1A upregulated PDGFRB, subsequently activated RhoA, and increased the phosphorylation of MLC2. PDGFRB also enhanced the phosphorylation of FAK. The OS cell morphology and vinculin distribution were altered by PDGFRB. PDGFRB promoted cell dedifferentiation and had a significant impact on the migration and invasion abilities of OS cells in vitro. In addition, PDGFRB increased pulmonary metastasis of OS cells in vivo. ConclusionOur results demonstrated that HIF1A up-regulated PDGFRB under hypoxic conditions, and PDGFRB regulated the actin cytoskeleton, a process likely linked to the activation of RhoA and the phosphorylation of, thereby promoting OS dedifferentiation and pulmonary metastasis.

Exploring transcriptomic mechanisms underlying pulmonary adaptation to diverse environments in Indian rams.

The Changthangi sheep thrive at high altitudes in the cold desert regions of Ladakh, India while Muzaffarnagri sheep are well-suited to the low altitude plains of northern India. This study investigates the molecular mechanisms of pulmonary adaptation to diverse environments by analyzing gene expression profiles of lung tissues through RNA sequencing. Four biological replicates of lung tissue from each breed were utilized to generate the transcriptomic data. Differences in gene expression analysis revealed discrete expression profiles in lungs of each breed. In Changthangi sheep, genes related to immune responses, particularly cytokine signaling, were significantly enriched. Pathway analysis highlighted the activation of NF-kB signaling, a key mediator of inflammation and immune response. Additionally, the gene network analysis indicated a strong association between cytokine signaling, hypoxia-inducible factor (HIF) and NF-kB activation, suggesting a coordinated response to hypoxic stress in lungs of Changthangi sheep. In Muzaffarnagri sheep, the gene expression profiles were enriched for pathways related to energy metabolism, homeostasis and lung physiology. Key pathways identified include collagen formation and carbohydrate metabolism, both of which are crucial for maintaining lung function and structural integrity. Gene network analysis further reinforced this by revealing a strong connection between genes associated with lung structure and function. Our findings shed light on the valuable insights into gene expression mechanisms that enable these sheep breeds to adapt to their respective environments and contribute to a better understanding of high altitude adaptation in livestock.

A polysaccharide from Periplaneta americana promotes macrophage M2 polarization, exhibiting anti-inflammatory and wound-healing activities

A miscellaneous polysaccharide, PAP55–3-1, with a molecular weight of 23.03 kDa, was isolated from Periplaneta americana through extraction with dilute alkali solution, ethanol precipitation, and column chromatography purification. Structural analysis shows that PAP55–3-1 is mainly composed of five monosaccharides: galactosamine hydrochloride, glucosamine hydrochloride, galactose, glucose and mannose. Its main glycosidic bonds are: Manp-(1→, Galp-(1→, →3)-Galp-(1→, →3,6)-Manp-(1→, →2,6)-Manp-(1→, →6)-Manp-(1→, →4)-Galp-(1→, →6-Glcp-(1→, →6)-Galp-(1→, →2)-Manp-(1 →, →3,4)-Glcp-(1→, →3,6)-Galp-(1→. In vitro experiments demonstrated that PAP55–3-1 can effectively inhibit reactive oxygen species (ROS) and O2− production following H2O2−induction. After H2O2−induction, HIF-1α (hypoxia-inducible factor) was translocated in mitochondria PAP55–3-1 increased localization of HIF-1α was located on mitochondria to maintain the stability of mitochondrial function stability, thereby effectively inhibiting H2O2-induced mitochondrial oxidative damage. Additionally, PAP55–3-1 inhibited the M1 polarization of macrophages stimulated by H2O2 and promoted the phenotype polarization of macrophages from M1 to M2, displaying anti-inflammatory and pro-repair properties. In vivo experimental results indicated that PAP55–3-1 promoted wound healing in mice. Immunohistochemical experiments revealed a reduction in CD68 expression and increase in CD206 expression in both positive and the high-dose polysaccharide group control group. This further demonstrated that PAP55–3-1 promotes the phenotype polarization of macrophages from M1 to M2, exerting anti-inflammatory and wound-healing activities.

Hypoxia-inducible factor-2α enhances neutrophil survival to promote cardiac injury following myocardial infarction.

Heart failure is a major cause of mortality following myocardial infarction. Neutrophils are among the first immune cells to accumulate in the infarcted region. Although beneficial functions of neutrophils in heart injury are now appreciated, neutrophils are also well known for their ability to exacerbate inflammation and promote tissue damage. Myocardial infarction induces hypoxia, where hypoxia-inducible factors (HIFs) are activated and play critical roles in cellular functions. In this context, the role of Hif2α in neutrophils during myocardial infarction is unknown. Here, we demonstrate that neutrophil Hif2α deletion markedly attenuates myocardial infarct size, improves cardiac function, reduces neutrophil survival and tissue accumulation, and correlates with increased macrophage engulfment rates. Mechanistic studies revealed that Hif2α promotes neutrophil survival through binding to hypoxia response element (HRE) in the promoter region of Birc2 to regulate expression of the prosurvival factor, cellular inhibitor of apoptosis protein-1 (cIAP1). Inhibition of cIAP1 in neutrophils using the pharmacological agent, Birinapant resulted in increased cell death, establishing a critical role of cIAP1 downstream of Hif2α in neutrophil survival. Taken together, our data demonstrate a protective effect of Hif2α deletion in neutrophils on cardiac injury outcomes through modulation of neutrophil cell survival.NEW & NOTEWORTHY Hif2α in neutrophils increases infarct size, cardiac dysfunction, and ventricular scar after myocardial infarction. Hif2α in neutrophils supports neutrophil survival via cIAP-1 signaling and delays macrophage engulfment.

Combined dapagliflozin and roxadustat effectively protected heart and kidney against cardiorenal syndrome-induced damage in rodent through activation of cell stress-Nfr2/ARE signalings and stabilizing HIF-1α

BackgroundThis study tested whether combined dapagliflozin (DAPA) and roxadustat (ROX) therapy was superior to a singular therapy in protecting heart and kidney functions in rats with cardiorenal syndrome (CRS). Methods and resultsAn in vitro study demonstrated that the cell survival (PI3K/Akt/mTOR)/cell stress (ERK1/2, JNK/p-38) signaling was significantly activated by combination therapy with ROX-DAPA (all p<0.001). Additionally, these two signaling pathways further significantly upregulated the hypoxia-induced factor (HIF)-1α which, in turn, significantly upregulated Nrf2/ARE (HO-1/NQO-1) and angiogenesis/cell-growth factors (EPO/SDF-1α/VEGF/FGF/IGF-2) and downregulated hypoxia-inducible factor prolyl-4-hydroxylase-1 (all p<0.001). Adult-male SD rats were categorized into Groups 1 (sham-operated control)/2 (CRS)/3 (CRS+ROX)/4 (CRS+DAPA)/5 (CRS+ROX+DAPA). By Day 60 after rodent CRS induction, the levels of BUN/creatinine and the ratio of urine protein to creatinine were lowest in Group 1, highest in Group 2, and significantly lower in Group 5 than in Groups 3 and 4; however, they were similar in the latter two groups, whereas the left-ventricular-ejection-fraction exhibited the opposite trend of creatinine among the groups (all p<0.0001). The protein expression levels of cell-survival (p-PI3K/p-Akt-p-mTOR)/cell-stress (p-JNK/p-p38/p-ERK1/2)/Nrf2-ARE (HO-1/NQO-1/SIRT1/SIRT3) signaling factors and angiogenesis factors (HIF-1α/VEGF/SDF-1α/FGF/IGF-2/EPO) significantly and progressively increased from Groups 1–5 (all p<0.0001). ConclusionCombined DAPA-ROX therapy has a synergistic effect on protecting heart and kidney functions against CRS-induced damage in rodents.

Chemistry, Analysis, and Biological Aspects of Daprodustat, A New Hypoxia Inducible Factor Prolyl Hydroxylase Inhibitor: A Comprehensive Review.

The National Health and Nutrition Examination Survey (NHANES) carried out a survey between 2007-10 and found that as compared to the general population, the prevalence of anemia in chronic kidney disease (CKD) patients was twice high. Daprodustat is an investigational novel drug for the treatment of renal anemia. The objective of this study is to provide a comprehensive review of chemistry, synthesis, pharmacology, pharmacokinetic, and bioanalytical methods for the analysis of Daprodustat. To improve understanding, a review was carried out by creating a database of relevant prior research from electronic sources such as ScienceDirect and PubMed. The methodology is shown in the flowchart of the literature selection process. The drug was approved in 2020 for therapeutic purposes in Japan. It is a novel drug approved for the treatment of anemia in chronic kidney disease for oral administration. It is intended for adults who have undergone dialysis for a minimum of four months and are experiencing anemia as a result of chronic kidney disease. This review examines therapeutic, pharmacological, and analytical aspects related to the novel drug Daprodustat.

Gelation embolism agents suppress clinical TACE-incited pro-metastatic microenvironment against hepatocellular carcinoma progression

Current embolic agents in transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) encounter instability and easy leakage, discounting TACE efficacy with residual HCC. Moreover, clinical TACE aggravates hypoxia and pro-metastatic microenvironments, rendering patients with HCC poor prognosis. Herein, we developed Zein-based embolic agents that harness water-insoluble but ethanol-soluble Zein to encompass doxorubicin (DOX)-loaded mesoporous hollow MnO2 (HMnO2). The conditions and capacity of HMnO2 to generate reactive oxygen species (ROS) were assayed. Mechanical examinations of Zein-HMnO2@DOX were performed to evaluate its potential as the embolic agent. Invitro experiments were carried out to evaluate the effect of Zein-HMnO2@DOX on HCC. The subcutaneous HCC mouse model and rabbit VX2 HCC model were established to investigate its anti-tumor and anti-metastasis efficacy and explore its potential anti-tumor mechanism. The high adhesion and crosslinking of Zein with HMnO2@DOX impart Zein-HMnO2@DOX with strong mechanical strength to resist deformation and wash-off. Zein gelation and HMnO2 decomposition in response to water and acidic tumor microenvironment, respectively, enable continuous DOX release and Fenton-like reaction for reactive oxygen species (ROS) production and O2 release to execute ROS-enhanced TACE. Consequently, Zein-based embolic agents outperform clinically-used lipiodol to significantly inhibit orthotopic HCC growth. More significantly, O2 release down-regulates hypoxia inducible factor (HIF-1α), vascular endothelial growth factor (VEGF) and glucose transporter protein 1 (GLUT1), which thereby re-programmes TACE-aggravated hypoxic and pro-metastatic microenvironments to repress HCC metastasis towards lung. Mechanistic explorations uncover that such Zein-based TACE agents disrupt oxidative stress, angiogenesis and glycometabolism pathways to inhibit HCC progression. This innovative work not only provides a new TACE agent for HCC, but also establishes a new strategy to ameliorate TACE-aggravated hypoxia and metastasis motivation against clinically-common HCC metastasis after TACE operation. Excellent Young Science Fund for National Natural Science Foundation of China (82022033); National Natural Science Foundation of China (Grant No. 82373086, 82102761); Major scientific and technological innovation project of Wenzhou Science and Technology Bureau (Grant No. ZY2021009); Shanghai Young Top-Notch Talent.

Mesenchymal Stem Cell-conditioned Medium Protecting Renal Tubular Epithelial Cells by Inhibiting Hypoxia-inducible Factor-1α and Nuclear Receptor Coactivator-1.

Acute kidney injury (AKI) is characterized by inflammatory infiltration and damage and death of renal tubular epithelial cells (RTECs), in which hypoxia plays an important role. Deferoxamine (DFO) is a well-accepted chemical hypoxia-mimetic agent. Mesenchymal stem cell-conditioned medium (MSC-CM) can reduce local inflammation and repair tissue. In this study, we explored the effect and molecular mechanism of MSC-CM-mediated protection of RTECs under DFO-induced hypoxia. Rat renal proximal tubule NRK-52E cells were treated with different concentrations of DFO for 24 hours, followed by evaluation of RTEC injury, using a Cell Counting Kit-8 (CCK-8) to detect cell viability and western blotting to evaluate the expression of transforming growth factor- beta 1 (TGF-β1), α-smooth muscle actin (α-SMA), and hypoxia-inducible factor-1 alpha (HIF-1α) in NRK-52E cells. Then, three groups of NRK-52E cells were used in experiments, including normal control (NC), 25 μM DFO, and 25 μM DFO + MSC-CM. MSC-CM was obtained from the human umbilical cord. MSC-CM was used to culture cells for 12 hours before DFO treatment, then fresh MSC-CM and 25 μM DFO were added, and cells were cultured for another 24 hours before analysis. Western blotting and cellular immunofluorescence staining showed culture of NRK-52E cells in 25 μM DFO for 24 hours induced HIF-1α and nuclear receptor coactivator-1 (NCoA-1), simulating hypoxia. MSC-CM could inhibit the DFO-induced up-regulation of α-SMA, TGF-β1, HIF-1α and NCoA-1. Our results suggest that MSC-CM has a protective effect on RTECs by down-regulating HIF-1α and NCoA-1, which may be the harmful factors in renal injury.