Regulation of hypoxia-inducible factor-1alpha by NF-kappaB

The molecular mechanism of NF-κB dysregulation across different subtypes of renal cell carcinoma

BACKGROUND

The nuclear factor kappa B (NF-κB) is a critical pathway that regulates various cellular functions, including immune response, proliferation, growth, and apoptosis. Furthermore, this pathway is tightly regulated to ensure stability in the presence of immunogenic triggers or genotoxic stimuli. The lack of control of the NF-κB pathway can lead to the initiation of different diseases, mainly autoimmune diseases and cancer, including Renal cell carcinoma (RCC). RCC is the most common type of kidney cancer and is characterized by complex genetic composition and elusive molecular mechanisms.

AIM OF REVIEW

The current review summarizes the mechanism of NF-κB dysregulation in different subtypes of RCC and its impact on pathogenesis.

KEY SCIENTIFIC CONCEPT OF REVIEW

This review highlights the prominent role of NF-κB in RCC development and progression by driving the expression of multiple genes and interplaying with different pathways, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. In silico analysis of RCC cohorts and molecular studies have revealed that multiple NF-κB members and target genes are dysregulated. The dysregulation includes receptors such as TLR2, signal-transmitting members including RelA, and target genes, for instance, HIF-1α. The lack of effective regulatory mechanisms results in a constitutively active NF-κB pathway, which promotes cancer growth, migration, and survival. In this review, we comprehensively summarize the role of dysregulated NF-κB-related genes in the most common subtypes of RCC, including clear cell RCC (ccRCC), chromophobe RCC (chRCC), and papillary RCC (PRCC).

A Novel Rabbit Model of Severe ARDS: Synergistic Effects of Acid Aspiration and Harmful Mechanical Ventilation

BACKGROUND

Acute respiratory distress syndrome (ARDS) is characterised by severe inflammation and pulmonary edema, often leading to respiratory failure. This study aims to develop a stable and relevant rabbit model of severe ARDS using hydrochloric acid (HCl) aspiration and ventilator-induced lung injury (VILI).

METHODS

Adult New Zealand rabbits were divided into four groups: Saline (n=9), 1-hit 3.0 (HCl 3 ml/kg, n=7), 1-hit 6.0 (HCl 6 ml/kg, n=7), and 2-hit (HCl 3 ml/kg and ventilation with VT 20 ml/kg, zero PEEP, RR 20-30 bpm, and FiO2 1.0 to mimic VILI, n=14). PaO2/FiO2 ratio, oxygenation index, oxygen saturation, PaCO2, ventilation efficiency index and alveolar-arterial gradient were evaluated every hour for 4 h after induction of lung injury. The post-mortem analysis included total and differential cell counts in bronchoalveolar lavage fluid (BALF), evaluation of lung edema formation, biochemical and histological examination of lung tissue.

RESULTS

In the 2-hit group, we observed a significant deterioration of all lung function parameters (P/F ratio, oxygenation index, ventilation efficacy index, and alveolar-arterial gradient) compared to the saline group. Similarly, a deterioration was observed in the 1-hit 6.0 group. When analysing the inflammatory profile, we observed significantly increased levels of chemokines and cytokines (TNFα, IL-1β, IL-6, IL-8, ET-1, MCP, H1F, MIP) and oxidative stress parameters (3NT, MDA, AOPP, catalase and GSH/GSSG) in BALF in the 2-hit group compared to the saline group. Intratracheal administration of HCl alone did not have a significant impact on inflammation as the combination of two insults. An increased wet-to-dry lung weight ratio (W/D), indicative of pulmonary edema, was observed in both the 2-hit and 1-hit 6.0 groups compared to the saline group. An increased level of protein content in BALF and total lung injury score were observed in the 2-hit group compared to the saline group, 1-hit 3.0 and 1-hit 6.0.

CONCLUSION

The combination of hydrochloric acid aspiration and ventilator-induced lung injury reliably reproduces key features of severe ARDS, offering a robust and clinically relevant model for investigating its complex pathophysiology and evaluating novel therapeutic interventions.

High-fat diet-induced osteoporosis in mice under hypoxic conditions

In the context of global aging, osteoporosis has emerged as a significant public health concern, with a relatively high prevalence observed in plateau regions. This study aimed to investigate the effects and underlying mechanisms of high-fat diet (HFD) and hypoxic conditions on bone metabolism in mice. The mice were subjected to different dietary regimens (a HFD versus a normal diet) and placed in a hypoxic environment. This study explored relevant mechanisms through comprehensive assessments, including body and bone morphological indices, pathological examinations, biochemical analyses, evaluation of gut microbiota diversity, and metabolomics approaches. The results indicated that, compared with those in the control group, the body weight, Lee's index, body mass index (BMI), and body fat percentage of the HFD-fed group were significantly greater. Additionally, the femoral microstructure was compromised, bone metabolic markers were disrupted, inflammatory responses were heightened, gut microbiota diversity was altered, and specific intestinal metabolites such as Anserine were downregulated, whereas L-carnosine was upregulated. Spearman correlation analysis and network visualization elucidated the multifactorial influence mechanism of a HFD on bone metabolism under hypoxic conditions. These factors interconnect to form a complex network that drives osteoporosis development. Notably, L-carnosine occupies a central position within this network, serving as a key hub for interactions among various factors. Under the dual stressors of hypoxia and a HFD, this network becomes imbalanced, leading to bone metabolic disorders and osteoporosis. This study provides insights into the multifactorial mechanisms of osteoporosis induced by a HFD and hypoxia in mice, offering a foundation for subsequent research and preventive strategies for osteoporosis in plateau areas.

SPP1 + macrophages cause exhaustion of tumor-specific T cells in liver metastases

Functional tumor-specific CD8+ T cells are essential for effective anti-tumor immune response and immune checkpoint inhibitor therapy. Here we show that, compared to other organ sites, primary, metastatic liver tumors in murine models contain a higher number of tumor-specific CD8+ T cells which are also dysfunctional. High-dimensional, multi-omic analysis of patient samples reveals a higher frequency of exhausted tumor-reactive CD8+ T cells and enriched interactions between these cells and SPP1+ macrophages in profibrotic, alpha-SMA rich regions specifically in the liver. Differential pseudotime trajectory inference analysis reveals that extrahepatic signaling promotes an intermediate cell (IC) population in the liver, characterized by co-expression of VISG4, CSF1R, CD163, TGF-βR, IL-6R, and SPP1. Analysis of premetastatic adenocarcinoma patient samples reveals enrichment of this population may predict liver metastasis. These findings suggest a mechanism by which extrahepatic tumors drive liver metastasis by promoting an IC population that inhibits tumor-reactive CD8+ T cell function.

Deciphering the role of circular RNAs in cancer progression under hypoxic conditions

Hypoxia, characterized by reduced oxygen levels, plays a pivotal role in cancer progression, profoundly influencing tumor behavior and therapeutic responses. A hallmark of solid tumors, hypoxia drives significant metabolic adaptations in cancer cells, primarily mediated by hypoxia-inducible factor-1α (HIF-1α), a key transcription factor activated in low-oxygen conditions. This hypoxic environment promotes epithelial-mesenchymal transition (EMT), enhancing cancer cell migration, metastasis, and the development of cancer stem cell-like properties, which contribute to therapy resistance. Moreover, hypoxia modulates the expression of circular RNAs (circRNAs), leading to their accumulation in the tumor microenvironment. These hypoxia-responsive circRNAs regulate gene expression and cellular processes critical for cancer progression, making them promising candidates for diagnostic and prognostic biomarkers in various cancers. This review delves into the intricate interplay between hypoxic circRNAs, microRNAs, and RNA-binding proteins, emphasizing their role as molecular sponges that modulate gene expression and signaling pathways involved in cell proliferation, apoptosis, and metastasis. It also explores the relationship between circRNAs and the tumor microenvironment, particularly how hypoxia influences their expression and functional dynamics. Additionally, the review highlights the potential of circRNAs as diagnostic and prognostic tools, as well as their therapeutic applications in innovative cancer treatments. By consolidating current knowledge, this review underscores the critical role of circRNAs in cancer biology and paves the way for future research aimed at harnessing their unique properties for clinical advancements. Specifically, this review examines the biogenesis, expression patterns, and mechanistic actions of hypoxic circRNAs, focusing on their ability to act as molecular sponges for microRNAs and their interactions with RNA-binding proteins. These interactions impact key signaling pathways related to tumor growth, metastasis, and drug resistance, offering new insights into the complex regulatory networks governed by circRNAs under hypoxic stress.

Circadian Biology in Obstructive Sleep Apnea-Associated Cardiovascular Disease

A dysregulated circadian system is independently associated with both Obstructive Sleep Apnea (OSA) and cardiovascular disease (CVD). OSA and CVD coexistence is often seen in patients with prolonged untreated OSA. However, the role of circadian dysregulation in their relationship is unclear. Half of the human genes, associated biological pathways, and physiological functions exhibit circadian rhythms, including blood pressure and heart rate regulation. Mechanisms related to circadian dysregulation and heart function are potentially involved in the coexistence of OSA and CVD. In this article, we provide a comprehensive overview of circadian dysregulation in OSA and associated CVD. We also discuss feasible animal models and new avenues for future research to understand their relationship. Oxygen-sensing pathways, inflammation, dysregulation of cardiovascular processes, oxidative stress, metabolic regulation, hormone signaling, and epigenetics are potential clock-regulated mechanisms connecting OSA and CVD.

Metabolic reprogramming of macrophages by a nano-sized opsonization strategy to restore M1/M2 balance for osteoarthritis therapy

Osteoarthritis is a chronic and progressive joint disease accompanied by cartilage degeneration and synovial inflammation. It is associated with an imbalance of synovial macrophage M1/M2 ratio tilting more towards the pro-inflammatory M1 than the anti-inflammatory M2. The M1-macrophages rely on aerobic glycolysis for energy whereas the M2-macrophages derive energy from oxidative phosphorylation. Therefore, inhibiting aerobic glycolysis to induce metabolic reprogramming of macrophages and consequently promote the shift from M1 type to M2 type is a therapeutic strategy for osteoarthritis. Here we developed a macrophage-targeting strategy based on opsonization, using nanoparticles self-assembled to incorporate Chrysin (an anti-inflammatory flavonoid) and V-9302 (an inhibitor of glutamine uptake), and the outer layer modified by immunoglobulin IgG by electrostatic adsorption into IgG/Fe-CV NPs. In vitro studies showed that IgG/Fe-CV NPs effectively target M1 macrophages and inhibit HIF-1α and GLUT-1 essential for aerobic glycolysis and promote polarization from M1 to M2-type macrophages. In vivo, IgG/Fe-CV NPs inhibit inflammation and protect against cartilage damage. The metabolic reprogramming strategy with IgG/Fe-CV NPs to shift macrophage polarization from inflammatory to anti-inflammatory phenotype by inhibiting aerobic glycolysis and glutamine delivery may open up new avenues to treat osteoarthritis.

Effects of in vitro cytochalasin D and hypoxia on mitochondrial energetics and biogenesis, cell signal status and actin/tubulin/Hsp/MMP entity in air-breathing fish heart

The cardiac actin cytoskeleton has a dynamic pattern of polymerisation. It is uncertain how far actin destabilisation impacts mitochondrial energetics and biogenesis, cell signal status, and structural entities in cardiomyocytes, particularly in hypoxic conditions. We thus tested the in vitro action of cytochalasin D (Cyt D), an inhibitor of actin polymerisation, in hypoxic ventricular explants to elucidate the role of the actin in mitochondrial energetics and biogenesis, cell signals and actin/tubulin/hsps/MMPs dynamics in hypoxic air-breathing fish hearts. The COX activity increased upon Cyt D exposure, whereas hypoxia lowered COX and SDH activities but increased LDH activity. The ROS increased, and NO decreased by Cyt D. COX and LDH activities, and NO content reversed after Cyt D exposure in hypoxic hearts. Cyt D exposure upregulated actin isoform expression (Actc1 and Actb1) but downregulated tubulin isoform (Tedc1). Hypoxia upregulated actin (Acta1a, Actb1, Actb2, Actc1a) tubulin (Tuba, Tubb5, Tedc1, Tubd1) and hsp (Hspa5, Hspa9, Hspa12a, Hspa14, Hspd1, Hsp90) isoform transcript expression and Cyt D in hypoxic hearts reversed these isoform's expression. Hypoxia upregulated Mmp2 and 9 transcript expressions but downregulated Mfn1, Fis1, Nfkb1, Prkacaa, and Aktip expressions, and Cyt D exposure reversed almost all these markers in hypoxic hearts. The data provide novel evidence for the mechanistic role of actin in integrating mitochondrial energetics and biogenesis, cell signal status and actin/tubulin/Hsp/MMP entity, indicating its critical cardioprotective role in defending against hypoxia. Besides proposing an air-breathing fish heart as a model, the study further brings the therapeutic potential of Cyt D towards hypoxia intervention.

Nidogen-1 suppresses cell proliferation, migration, and glycolysis via integrin β1-mediated HIF-1α downregulation in triple-negative breast cancer

Nidogen-1 (NID1) is a secreted glycoprotein widely distributed in basement membranes. NID1 interacts with extracellular matrix proteins such as collagen and laminin and has been implicated in the progression of various cancers. However, study on the role of NID1 in breast cancer is scarce and inconsistent. In this work, we found that the expression of NID1 is significantly lower in breast cancer tissue than in normal tissue. In addition, NID1 expression correlated negatively with a poor prognosis for breast cancer patients. Based on those findings, we speculated that NID1 might act as a cancer suppressor in breast cancer. To investigate the role of NID1 in breast cancer, we constructed NID1-overexpressing cell lines. NID1 overexpression decreased breast cancer cell proliferation, migration, and in vivo tumor growth. Moreover, glucose metabolism, which is known to enhance cancer cell proliferation and migration, was also decreased by NID1 overexpression. Mechanistically, NID1 overexpression downregulated hypoxia-inducible factor-1α (HIF-1α) expression at the transcription level. Furthermore, we found that NID1 reduced integrin β1 stability and downregulated the transcription of HIF-1α through the FAK/Src/NF-κB p65 signaling axis, which is downstream of integrin β1. Together, the results of this study demonstrate the tumor suppressive role of NID1 in triple-negative breast cancer.

Organ preservation: current limitations and optimization approaches

Despite the annual rise in patients with end-stage diseases necessitating organ transplantation, the scarcity of high-quality grafts constrains the further development of transplantation. The primary causes of the graft shortage are the scarcity of standard criteria donors, unsatisfactory organ preservation strategies, and mismatching issues. Organ preservation strategies are intimately related to pre-transplant graft viability and the incidence of adverse clinical outcomes. Static cold storage (SCS) is the current standard practice of organ preservation, characterized by its cost-effectiveness, ease of transport, and excellent clinical outcomes. However, cold-induced injury during static cold preservation, toxicity of organ preservation solution components, and post-transplantation reperfusion injury could further exacerbate graft damage. Long-term ex vivo dynamic machine perfusion (MP) preserves grafts in a near-physiological condition, evaluates graft viability, and cures damage to grafts, hence enhancing the usage and survival rates of marginal organs. With the increased use of extended criteria donors (ECD) and advancements in machine perfusion technology, static cold storage is being gradually replaced by machine perfusion. This review encapsulates the latest developments in cryopreservation, subzero non-freezing storage, static cold storage, and machine perfusion. The emphasis is on the injury mechanisms linked to static cold storage and optimization strategies, which may serve as references for the optimization of machine perfusion techniques.

The Roles and Molecular Mechanisms of HIF-1α in Pulpitis

Pulpitis is characterized by inflammation within dental pulp tissue, primarily triggered by bacterial infection. Hypoxia-inducible factor-1α (HIF-1α), a key transcriptional regulator, is stabilized under the hypoxic conditions associated with pulpitis. This review examines the roles and molecular mechanisms of HIF-1α in the pathogenesis and progression of pulpitis. Hypoxia in pulpitis prevents the degradation of HIF-1α, leading to its elevated expression. Furthermore, lipopolysaccharide from invading bacteria upregulates HIF-1α transcription through nuclear factor kappa B and mitogen-activated protein kinase pathways. HIF-1α regulates immunity and pulp remodeling in a stage-dependent manner by controlling various cytokines. During the inflammation stage, HIF-1α promotes recruitment of neutrophils and enhances their bactericidal effects by facilitating neutrophil extracellular trap release and M1 macrophage polarization. Concurrently, HIF-1α contributes to programmed cell death by increasing mitophagy. In the proliferation stage, HIF-1α stimulates immune responses involving T cells and dendritic cells. In the remodeling stage, HIF-1α supports angiogenesis and pulp-dentin regeneration. However, excessive pulpitis-induced hypoxia may disrupt vascular dynamics within the pulp chamber. This disruption highlights a critical threshold for HIF-1α, beyond which its effects might accelerate pulp necrosis. Overall, HIF-1α plays a central role in regulating immunity and tissue remodeling during pulpitis. A comprehensive understanding of the physiological and pathological roles of HIF-1α is essential for the advancement of effective strategies to manage irreversible pulpitis.

Natural flavonoid Orientin restricts 5-Fluorouracil induced cancer stem cells mediated angiogenesis by regulating HIF1α and VEGFA in colorectal cancer

BACKGROUND

Cancer stem cells are a small subpopulation of cells which are responsible for tumor metastasis, angiogenesis, drug resistance etc. 5-Fluorouracil (5FU), a common therapeutic drug used in colorectal cancer treatment is reported to enrich CSCs, tumor recurrence and induces severe organ toxicities resulting in poor clinical outcome in patients. Therefore, we introduced a natural flavonoid Orientin in combination with 5FU to mitigate the CSC mediated angiogenesis and induced toxicities.

METHODS

Tumorosphere generation, flow cytometry, immunofluorescence assay, and western blotting were performed by using 5FU and Orientin individually and both treated colorectal cells and CSCs. In silico study was carried out to check the interaction between HIF1α and Orientin. In ovo chorioallantoic membrane (CAM) assay and tube formation assay using HUVECs were performed to monitor CSC mediated angiogenesis. In vivo CT26 syngeneic mice model was used to validate in silico and ex vivo results.

RESULTS

We found that 5FU treatment significantly increased the CD44+/CD133+ CSC population. In contrast, this CSC population in CSC enriched spheres (CES) derived from HCT116 cells were decreased by combination of Orientin and 5FU. Decrease of CSC's stemness properties was also noted, as evidenced by the downregulation of NANOG, SOX2 and OCT4. This new therapeutic strategy also inhibited CSC mediated angiogenesis by downregulating 5FU induced ROS, NO and LPO in those tumorospheres. Combination of Orientin and 5FU significantly reduced CSC mediated angiogenesis in HUVEC and CAM. Additionally, in silico study predicted that Orientin can bind to the PAS domain of HIF1α, a crucial factor for promoting angiogenesis. Expression of HIF1α and VEGFA were also decreased when the CESs were exposed to the combinatorial treatment. Additionally, we found that treatment with 5FU alone resulted reduction in tumor volume but it enriched CSCs and produced nephrotoxicity and hepatotoxicity in vivo. Combined treatment also considerably reduced the CD44+/CD133+ CSC population and hindered angiogenesis in a therapeutic in vivo model in BALB/c mice.

CONCLUSIONS

This novel treatment strategy of "Orientin with 5FU" is likely to improve the efficiency of conventional chemotherapy and may suppress disease recurrence in colorectal cancer by limiting CSC mediated angiogenesis.

Regulation of pathologic fibroblast functions in digestive diseases: a role for hypoxia?

The recent uncovering of fibroblast heterogeneity has given great insight into the versatility of the stroma. Among other cellular processes, fibroblasts are now thought to contribute to the coordination of immune responses in a range of chronic inflammatory diseases and cancer. Although the pathologic roles of myofibroblasts, inflammatory fibroblasts, and cancer-associated fibroblasts in disease are reasonably well understood, the mechanisms behind their activation remain to be uncovered. In the gastrointestinal (GI) tract, several interleukins and tumor necrosis factor superfamily members have been identified as possible mediators driving the acquisition of inflammatory and fibrotic properties in fibroblasts. In addition to cytokines, other microenvironmental factors such as nutrient and oxygen availability are likely contributors to this process. In this respect, the phenomenon of low cellular oxygen levels known as hypoxia is common in a plethora of GI diseases. Indeed, the cross talk between hypoxia and inflammation is well-documented, with an abundance of studies suggesting that oxygen-sensing enzymes may have regulatory effects on inflammatory signaling pathways such as NF-κB. However, the impact that this has in GI fibroblasts in the context of chronic diseases has not been fully uncovered. Here we discuss the role of fibroblasts in GI diseases, the mediators that have emerged as regulators of their functions and the potential impact of hypoxia in this process, highlighting areas that require further investigation.

Morphofunctional changes in the immune system in colitis-associated colorectal cancer in tolerant and susceptible to hypoxia mice

Background

One of the effective strategies for the treatment of tumor diseases, including colitis-associated colorectal cancer (CAC), is immunotherapy. During inflammation, NF-κB is activated, which is connected with the hypoxia-inducible factor-HIF, regulating the immune cells functioning and influences the CAC development. Organisms differ according to their hypoxia resistance and HIF expression. Therefore, the aim of the study was to characterize the thymus, spleen and mesenteric lymph nodes morphofunctional features, as well as changes in the subpopulation composition of peripheral blood cells and mesenteric lymph nodes in tolerant and susceptible to hypoxia C57Bl/6 mice in CAC.

Methods

Hypoxia tolerance was assessed by gasping time measurement in hypobaric decompression chamber. Based on the outcome, the mice were assigned to three groups characterized as 'tolerant to hypoxia', 'normal', and 'susceptible to hypoxia'. A month after determining hypoxia resistance CAC was modeled by intraperitoneal azoxymethane (AOM) administration and three cycles of dextran sulfate sodium consumption. Mice were sacrificed on the 141st day after the AOM administration, a morphological, morphometric and immunohistochemical study of tumors, morphological and morphometric study of thymus and spleen, and subpopulation composition of peripheral blood cells and mesenteric lymph nodes assessment were carried out.

Results

Tumors in tolerant and susceptible to hypoxia mice were represented by glandular intraepithelial neoplasia and adenocarcinomas, the area of which was larger in susceptible mice. Immunohistochemical study revealed a more pronounced Ki-67+ staining in tumors of susceptible mice. In CAC, only in tolerant mice, expansion of the thymic cortex was observed relative to the control group, while in susceptible ones, no changes were detected. Only in susceptible to hypoxia mice, spleen germinal centers of lymphoid follicles enlargement were observed. Only in susceptible mice during CAC, in comparison to the control group, the relative and absolute number of B-lymphocytes and relative-cytotoxic T-lymphocytes in blood increased. The relative cytotoxic T-lymphocytes and NK cells number in peripheral blood during CAC was higher in susceptible to hypoxia mice compared to tolerant ones. In susceptible to hypoxia mice, more pronounced changes in the mesenteric lymph nodes subpopulation composition of cells were revealed-only in them the absolute and relative number of B-lymphocytes and NK cells, the absolute number of cytotoxic T-lymphocytes increased, and the relative number of macrophages decreased.

Conclusions

Morphofunctional differences in the thymus, spleen, mesenteric lymph nodes and blood immune cells reactions indicated the more pronounced immune response to the CAC development in susceptible to hypoxia mice, which should be taken into account in experimental studies.

The Role of Hypoxia in Longevity

Aging is marked by a progressive decrease in physiological function and reserve capacity, which results in increased susceptibility to diseases. Understanding the mechanisms of driving aging is crucial for extending health span and promoting human longevity. Hypoxia, marked by reduced oxygen availability, has emerged as a promising area of study within aging research. This review explores recent findings on the potential of oxygen restriction to promote healthy aging and extend lifespan. While the role of hypoxia-inducible factor 1 (HIF-1) in cellular responses to hypoxia is well-established, its impact on lifespan remains complex and context-dependent. Investigations in invertebrate models suggest a role for HIF-1 in longevity, while evidence in mammalian models is limited. Hypoxia extends the lifespan independent of dietary restriction (DR), a known intervention underlying longevity. However, both hypoxia and DR converge on common downstream effectors, such as forkhead box O (FOXO) and flavin-containing monooxygenase (FMOs) to modulate the lifespan. Further work is required to elucidate the molecular mechanisms underlying hypoxia-induced longevity and optimize clinical applications. Understanding the crosstalk between HIF-1 and other longevity-associated pathways is crucial for developing interventions to enhance lifespan and healthspan. Future studies may uncover novel therapeutic strategies to promote healthy aging and longevity in human populations.

Dihydromyricetin attenuates lipopolysaccharide-induced intestinal injury in weaned piglets by regulating oxidative stress and inhibiting NLRP3 inflammasome

This study explored the effects of dihydromyricetin (DHM) on lipopolysaccharide (LPS)-induced intestinal injury in weaned piglets and also investigated its possible molecular mechanism. The results showed that dietary supplementation of DHM could improve the jejunum morphological structure of piglets induced by LPS, reduce jejunum mucosa inflammation and endoplasmic reticulum stress, increase jejunum mucosa antioxidant capacity and the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and improve jejunum mucosa permeability. In addition, DHM downregulated the expression of toll-like receptor 4 (TLR4), phosphor-nuclear factor kappa-B (NF-κB), hypoxia-inducible factor-1α (HIF-1α), and the activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome. Taken together, LPS could induce jejunum mucosa injury in weaned piglets, but dietary supplementation of DHM alleviated LPS-induced jejunum mucosa injury to a certain extent, and the mechanism may be related to the activation of Nrf2 to inhibit the oxidative stress and negatively regulate the activation of the TLR4/HIF-1α/NLRP3 signaling axis.

Leveraging thiol-functionalized biomucoadhesive hybrid nanoliposome for local therapy of ulcerative colitis

Directly administering medication to inflamed intestinal sites for treating ulcerative colitis (UC), poses significant challenges like retention time, absorption variability, side effects, drug stability, and non-specific delivery. Recent advancements in therapy to treat colitis aim to improve local drug availability that is enema therapy at the site of inflammation, thereby reducing systemic adverse effects. Nevertheless, a key limitation lies in enemas' inability to sustain medication in the colon due to rapid peristaltic movement, diarrhea, and poor local adherence. Therefore, in this work, we have developed site-specific thiolated mucoadhesive anionic nanoliposomes to overcome the limitations of conventional enema therapy. The thiolated delivery system allows prolonged residence of the delivery system at the inflamed site in the colon, confirmed by the adhesion potential of thiolated nanoliposomes using in-vitro and in-vivo models. To further provide therapeutic efficacy thiolated nanoliposomes were loaded with gallic acid (GA), a natural compound known for its antibacterial, antioxidant, and potent anti-inflammatory properties. Consequently, Gallic Acid-loaded Thiolated 2,6 DALP DMPG (GATh@APDL) demonstrates the potential for targeted adhesion to the inflamed colon, facilitated by their small size 100 nm and anionic nature. Therapeutic studies indicate that this formulation offers protective effects by mitigating colonic inflammation, downregulating the expression of NF-κB, HIF-1α, and MMP-9, and demonstrating superior efficacy compared to the free GA enema. The encapsulated GA inhibits the NF-κB expression, leading to enhanced expression of MUC2 protein, thereby promoting mucosal healing in the colon. Furthermore, GATh@APDL effectively reduces neutrophil infiltration and regulates immune cell quantification in colonic lamina propria. Our findings suggest that GATh@APDL holds promise for alleviating UC and addressing the limitations of conventional enema therapy.

Expression and Regulation of Hypoxia-Inducible Factor Signalling in Acute Lung Inflammation

Hypoxia-inducible factors (HIFs) are central regulators of gene expression in response to oxygen deprivation, a common feature in critical illnesses. The significant burden that critical illnesses place on global healthcare systems highlights the need for a deeper understanding of underlying mechanisms and the development of innovative treatment strategies. Among critical illnesses, impaired lung function is frequently linked to hypoxic conditions. This review focuses on the expression and regulation of HIF signalling in experimental models of acute lung injury (ALI) and clinical studies in critically ill patients with acute respiratory distress syndrome (ARDS). We explore the potential dual role of HIF signalling in acute lung inflammation. Furthermore, its role in key biological processes and its potential prognostic significance in clinical scenarios are discussed. Finally, we explore recent pharmacological advancements targeting HIF signalling, which have emerged as promising alternatives to existing therapeutic approaches, potentially enabling more effective management strategies.

Metabolic Reprograming of Macrophages: A New Direction in Traditional Chinese Medicine for Treating Liver Failure

Acute liver failure (ALF) is a fulminant clinical syndrome that usually leads to multiple organ failure and high mortality. Macrophages play a crucial role in the initiation, development, and recovery of ALF. Targeting macrophages through immunotherapy holds significant promise as a therapeutic strategy. These cells exhibit remarkable plasticity, enabling them to differentiate into various subtypes based on changes in their surrounding microenvironment. M1-type macrophages are associated with a pro-inflammatory phenotype and primarily rely predominantly on glycolysis. In contrast, M2-type macrophages, which are characterized by anti-inflammatory phenotype, predominantly obtain their energy from oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO). Shifting macrophage metabolism from glycolysis to OXPHOS inhibits M1 macrophage activation and promotes M2 macrophage activation, thereby exerting anti-inflammatory and reparative effects. This study elucidates the relationship between macrophage activation and glucose metabolism reprograming from an immunometabolism perspective. A comprehensive literature review revealed that several signaling pathways may regulate macrophage polarization through energy metabolism, including phosphatidyl-inositol 3-kinase/protein kinase B (PI3K/AKT), mammalian target of rapamycin (mTOR)/hypoxia-inducible factor 1α (HIF-1α), nuclear factor-κB (NF-κB), and AMP-activated protein kinase (AMPK), which exhibit crosstalk with one another. Additionally, we systematically reviewed several traditional Chinese medicine (TCM) monomers that can modulate glucose metabolism reprograming and influence the polarization states of M1 and M2 macrophages. This review aimed to provide valuable insights that could contribute to the development of new therapies or drugs for ALF.

Understanding the role of TNFR2 signaling in the tumor microenvironment of breast cancer

Breast cancer (BC) is the most frequently diagnosed malignancy among women. It is characterized by a high level of heterogeneity that emerges from the interaction of several cellular and soluble components in the tumor microenvironment (TME), such as cytokines, tumor cells and tumor-associated immune cells. Tumor necrosis factor (TNF) receptor 2 (TNFR2) appears to play a significant role in microenvironmental regulation, tumor progression, immune evasion, drug resistance, and metastasis of many types of cancer, including BC. However, the significance of TNFR2 in BC biology is not fully understood. This review provides an overview of TNFR2 biology, detailing its activation and its interactions with important signaling pathways in the TME (e.g., NF-κB, MAPK, and PI3K/Akt pathways). We discuss potential therapeutic strategies targeting TNFR2, with the aim of enhancing the antitumor immune response to BC. This review provides insights into role of TNFR2 as a major immune checkpoint for the future treatment of patients with BC.

[Research Progress in the Role of Hypoxia-Inducible Factor 1 in Altitude Sickness and the Mechanisms Involved]

Individuals who reside at high altitudes for extended periods or those who visit these regions briefly frequently experience high-altitude response, which triggers a series of physiological and pathological changes in the body, ultimately causing altitude sickness. One of the most critical features of high-altitude environments is hypoxia. Recent studies have demonstrated that hypoxia-inducible factor 1 (HIF-1) plays a central role in mediating the body's response to hypoxic conditions at high altitudes. HIF-1, a heterodimeric transcription factor composed of an oxygen-sensitive subunit α (HIF-1α) and a constitutively expressed subunit β (HIF-1β), directly regulates the expression of multiple target genes, thereby modulating various physiological processes essential for cellular adaptation to hypoxia. According to a substantial body of research, aberrant expression of HIF-1 is implicated in the pathogenesis and progression of various diseases, including altitude sickness, cardiovascular disorders, neurological conditions, inflammatory diseases, cognitive impairment, immune dysregulation, and cancer. In this review, we provided an in-depth examination of the structural characteristics and regulatory mechanisms governing HIF-1 expression, discussed its downstream target genes, and highlighted the inhibitors currently under development. Additionally, we summarized the pivotal role and underlying mechanisms of HIF-1 in the development of altitude sickness, particularly its regulatory role in the pathophysiological processes of high-altitude pulmonary edema (HAPE), high-altitude cerebral edema (HACE), and high-altitude pulmonary hypertension (HAPH). Through a thorough examination of the role of HIF-1, we aim to provide a theoretical foundation and potential therapeutic targets for the prevention and treatment of altitude sickness.

Hypoxia-inducible factors (HIFs) in early pregnancy: implications for miscarriage†

Miscarriage poses a significant threat to both maternal and fetal health. Its etiology remains unknown, and there are no established effective identification or prevention strategies. A low-oxygen environment in early pregnancy is a physiological necessity for embryonic and placental growth. Hypoxia-inducible factors are a family of classic hypoxia signaling molecules whose expression level may fluctuate abnormally because of an imbalance in oxygen levels. Its unusual fluctuations initiate multiple signaling pathways at the maternal womb. Hypoxia-inducible factors are a family of classic hypoxia-signaling molecules and immune tolerance. Notably, aberrant regulation of these processes may lead to miscarriage. This review aims to clarify how the hypoxia-inducible factor-1α mediates the aberrant regulation of biological processes, including autophagy, metabolic reprogramming, et al., and how these effects impact trophoblasts and other cells at the maternal-fetal interface. These findings provide new insights into potential therapeutic and preventive strategies for miscarriage.

A ROS-Responsive Lipid Nanoparticles Release Multifunctional Hydrogel Based on Microenvironment Regulation Promotes Infected Diabetic Wound Healing

The continuous imbalance of the diabetic wound microenvironment is an important cause of chronic nonhealing, which manifests as a vicious cycle between excessive accumulation of reactive oxygen species (ROS) and abnormal healing. Regulating the microenvironment by suppressing wound inflammation, oxidative stress, and bacterial infection is a key challenge in treating diabetic wounds. In this study, ROS-responsive hydrogels are developed composed of silk fibroin methacrylated (SFMA), modified collagen type III (rCol3MA), and lipid nanoparticles (LNPs). The newly designed hydrogel system demonstrated stable physicochemical properties and excellent biocompatibility. Moreover, the release of antimicrobial peptide (AMP) and puerarin (PUE) demonstrated remarkable efficacy in eradicating bacteria, regulating inflammatory responses, and modulating vascular functions. This multifunctional hydrogel is a simple and efficient approach for the treatment of chronic diabetic infected wounds and holds tremendous potential for future clinical applications.

Astrocyte TrkB promotes brain injury and edema formation in ischemic stroke

Following ischemic stroke astrocytes undergo rapid molecular and functional changes that may accentuate tissue damage. In this study we identified the neurotrophin receptor TrkB in astrocytes as a key promoter of acute CNS injury in ischemic stroke. In fact, TrkB protein was strongly upregulated in astrocytes after human and experimental stroke, and transgenic mice lacking astrocyte TrkB displayed significantly smaller lesion volume, lower brain atrophy and better motor performance than control animals after transient middle cerebral artery occlusion. Neuropathological studies evidenced that edema directly correlated with astrogliosis and was limited in transgenic mice. Importantly, adaptive levels of the water channel AQP4 was astrocyte TrkB-dependent as AQP4 upregulation after stroke did not occur in mice lacking astrocyte TrkB. In vitro experiments with wild-type and/or TrkB-deficient astrocytes highlighted TrkB-dependent upregulation of AQP4 via activation of HIF1-alpha under hypoxia. Collectively, our observations indicate that TrkB signaling in astrocytes contributes to the development of edema and worsens cerebral ischemia.

Acute hypoxic conditions preceding endotoxin administration result in an increased proinflammatory cytokine response in healthy men

Tissues often experience hypoxia at sites of inflammation due to malperfusion, massive immune cell recruitment, and increased oxygen consumption. Organisms adapt to these hypoxic conditions through the transcriptional activation of various genes. In fact, there is significant crosstalk between the transcriptional responses to hypoxia and inflammatory processes. This interaction, named inflammatory hypoxia, plays a crucial role in various diseases including malignancies, chronic inflammatory lung diseases, and sepsis. To further elucidate the crosstalk between hypoxia and inflammation in vivo and assess its potential for innovative therapies, our study aimed at investigating the impact of acute hypoxic conditions on inflammation-induced immune responses. To this end, we exposed healthy human subjects to hypoxia either before (hypoxia priming) or after a single intravenous (i.v.) injection of 0.4 ng/kg LPS. Our data show that hypoxia exposure prior to LPS injection (hypoxia priming) amplified the proinflammatory response. This was reflected by an increase in body temperature, plasma noradrenaline levels, and the production of proinflammatory cytokines (i.e., IL-6 and TNF-α), compared with LPS control conditions. These effects were not observed when participants were exposed to hypoxia after LPS administration, demonstrating that the interaction between hypoxia and inflammation highly depends on the timing of both stimuli. Our findings suggest that acute hypoxia (i.e., hypoxia priming) modulates transient inflammation, leading to an enhanced proinflammatory response in healthy human subjects. This highlights the need for further investigations to understand the pathology of various hypoxia-inducible factor (HIF)-associated inflammatory diseases and to develop suitable, innovative therapies.NEW & NOTEWORTHY To our knowledge, this is the first in vivo study investigating the effects of hypoxia preceding (hypoxia priming) or following LPS administration on the endotoxin-induced inflammatory response in healthy human subjects. The data show that hypoxia priming amplified the proinflammatory response, reflected by an increased body temperature, increased plasma noradrenaline levels, and higher production of proinflammatory cytokines (i.e., IL-6 and TNF-α) compared with LPS control conditions.

CBX7 promotes choroidal neovascularization by activating the HIF-1α/VEGF pathway in choroidal vascular endothelial cells

Vascular endothelial growth factor (VEGF) signaling is crucial for choroidal neovascularization (CNV), a major pathological feature of neovascular age-related macular degeneration (nAMD). Gene transcription of VEGF is mainly regulated by hypoxia-inducible factor 1-alpha (HIF-1α). The chromobox (CBX) family polycomb protein (Pc) subgroup includes CBX2, CBX4, CBX6, CBX7, and CBX8. CBX4 enhances hypoxia-induced VEGF expression and angiogenesis in hepatocellular carcinoma (HCC) cells by increasing HIF-1α's transcriptional activity. The objective of the study was to examine the functions of members of the CBX family Pc subgroup in choroidal vascular endothelial cells (CVECs) during CNV. CBX4 and CBX7 expression was up-regulated in hypoxic human choroidal vascular endothelial cells (HCVECs). In HCVECs, CBX7 facilitated HIF-1α transcription and expression, while CBX4 did not. In HCVECs, CBX7 stimulated HIF-1α's nuclear translocation and transcriptional activity, which in turn stimulated VEGF transcription and expression. The CBX7/HIF-1α/VEGF pathway promoted the migration, proliferation, and tube formation of HCVECs. The CBX7/HIF-1α/VEGF pathway was up-regulated in CVECs and in the mouse model with laser-induced CNV. Mouse CNV was lessened by the blockade of CBX7 through the down-regulation of HIF-1α/VEGF. In conclusion, CBX7 enhanced pro-angiogenic behaviors of hypoxic CVECs by up-regulating the HIF-1α/VEGF pathway, which contributing to the formation of mouse laser-induced CNV.

Inflammation in a ferroptotic environment

Ferroptosis is an iron-dependent form of cell death, which finally culminates in lipid peroxidation and membrane damage. During the past decade, the interest in ferroptosis increased substantially and various regulatory components were discovered. The role of ferroptosis during inflammation and its impact on different immune cell populations is still under debate. Activation of inflammatory pathways such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and hypoxia inducible factors (HIFs) are known to alter the ability of cells to undergo ferroptosis and are closely connected to iron metabolism. During inflammation, iron regulatory systems fundamentally change and cells such as macrophages and neutrophils adapt their metabolism towards iron sequestering phenotypes. In this review, we discuss how ferroptosis alters inflammatory pathways and how iron metabolism under inflammatory conditions affects immune cell ferroptosis.

Neuronal extracellular vesicles influence the expression, degradation and oligomeric state of fructose 1,6-bisphosphatase 2 in astrocytes affecting their glycolytic capacity

Fructose 1,6-bisphosphatase 2 (Fbp2) is a regulatory enzyme of gluco- and glyconeogenesis which, in the course of evolution, acquired non-catalytic functions. Fbp2 promotes cell survival during calcium stress, regulates glycolysis via inhibition of Hif-1α activity, and is indispensable for the formation of long-term potentiation in hippocampus. In hippocampal astrocytes, the amount of Fbp2 protein is reduced by signals delivered in neuronal extracellular vesicles (NEVs) through an unknown mechanism. The physiological role of Fbp2 (determined by its subcellular localization/interactions) depends on its oligomeric state and thus, we asked whether the cargo of NEVs is sufficient to change also the ratio of Fbp2 dimer/tetramer and, consequently, influence astrocyte basal metabolism. We found that the NEVs cargo reduced the Fbp2 mRNA level, stimulated the enzyme degradation and affected the cellular titers of different oligomeric forms of Fbp2. This was accompanied with increased glucose uptake and lactate release by astrocytes. Our results revealed that neuronal signals delivered to astrocytes in NEVs provide the necessary balance between enzymatic and non-enzymatic functions of Fbp2, influencing not only its amount but also subcellular localization. This may allow for the metabolic adjustments and ensure protection of mitochondrial membrane potential during the neuronal activity-related increase in astrocytic [Ca2+].

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.

Divergent Processing of Cell Stress Signals as the Basis of Cancer Progression: Licensing NFκB on Chromatin

Inflammation is activated by diverse triggers that induce the expression of cytokines and adhesion molecules, which permit a succession of molecules and cells to deliver stimuli and functions that help the immune system clear the primary cause of tissue damage, whether this is an infection, a tumor, or a trauma. During inflammation, short-term changes in the expression and secretion of strong mediators of inflammation occur, while long-term changes occur to specific groups of cells. Long-term changes include cellular transdifferentiation for some types of cells that need to regenerate damaged tissue, as well as death for specific immune cells that can be detrimental to tissue integrity if they remain active beyond the boundaries of essential function. The transcriptional regulator NFκB enables some of the fundamental gene expression changes during inflammation, as well as during tissue development. During recurrence of malignant disease, cell stress-induced alterations enable the growth of cancer cell clones that are substantially resistant to therapeutic intervention and to the immune system. A number of those alterations occur due to significant defects in feedback signal cascades that control the activity of NFκB. Specifically, cell stress contributes to feedback defects as it overrides modules that otherwise control inflammation to protect host tissue. NFκB is involved in both the suppression and promotion of cancer, and the key distinctive feature that determines its net effect remains unclear. This paper aims to provide a clear answer to at least one aspect of this question, namely the mechanism that enables a divergent response of cancer cells to critical inflammatory stimuli and to cell stress in general.

Unraveling the Triad: Hypoxia, Oxidative Stress and Inflammation in Neurodegenerative Disorders

The mammalian brain's complete dependence on oxygen for ATP production makes it highly susceptible to hypoxia, at high altitudes or in clinical scenarios including anemia or pulmonary disease. Hypoxia plays a crucial role in the development of various brain disorders, such as Alzheimer's, Parkinson's, and other age-related neurodegenerative diseases. On the other hand, a decrease in environmental oxygen levels, such as prolonged stays at high elevations, may have beneficial impacts on the process of ageing and the likelihood of death. Additionally, the utilization of controlled hypoxia exposure could potentially serve as a therapeutic approach for age-related brain diseases. Recent findings indicate that the involvement of HIF-1α and the NLRP3 inflammasome is of significant importance in the development of Alzheimer's disease. HIF-1α serves as a pivotal controller of various cellular reactions to oxygen deprivation, exerting influence on a multitude of physiological mechanisms such as energy metabolism and inflammatory responses. The NLRP3 plays a crucial role in the innate immune system by coordinating the initiation of inflammatory reactions through the assembly of the inflammasome complex. This review examines the information pertaining to the contrasting effects of hypoxia on the brain, highlighting both its positive and deleterious effects and molecular pathways that are involved in mediating these different effects. This study explores potential strategies for therapeutic intervention that focus on restoring cellular balance and reducing neuroinflammation, which are critical aspects in addressing this severe neurodegenerative condition and addresses crucial inquiries that warrant further future investigations.

FG-4592 protected haematopoietic system from ionising radiation in mice

Ionising radiation exposure can lead to acute haematopoietic radiation syndrome. Despite significant advancements in the field of radioprotection, no drugs with high efficacy and low toxicity have yet been approved by the Food and Drug Administration. FG-4592, as a proline hydroxylase inhibitor, may play an important role in radioprotection of the haematopoietic system. Mice were peritoneal injected with FG-4592 or normal saline. After irradiation, the survival time, body weight, peripheral blood cell and bone marrow cell (BMC) count, cell apoptosis, pathology were analysed and RNA-sequence technique (RNA-Seq) was conducted to explore the mechanism of FG-4592 in the haematopoietic system. Our results indicated that FG-4592 improved the survival rate and weight of irradiated mice and protected the spleen, thymus and bone marrow from IR-induced injury. The number of BMCs was increased and protected against IR-induced apoptosis. FG-4592 also promoted the recovery of the blood system and erythroid differentiation. The results of RNA-Seq and Western blot showed that the NF-κB signalling pathway and hypoxia-inducible factor-1 (HIF-1) signalling pathway were upregulated by FG-4592. Meanwhile, RT-PCR results showed that FG-4592 could promote inflammatory response significantly. FG-4592 exhibited radioprotective effects in the haematopoietic system by promoting inflammatory response and targeting the NF-κB, HIF signalling pathway.

Renoprotective effect of a novel combination of 6-gingerol and metformin in high-fat diet/streptozotocin-induced diabetic nephropathy in rats via targeting miRNA-146a, miRNA-223, TLR4/TRAF6/NLRP3 inflammasome pathway and HIF-1α

BACKGROUND

MiRNA-146a and miRNA-223 are key epigenetic regulators of toll-like receptor 4 (TLR4)/tumor necrosis factor-receptor-associated factor 6 (TRAF6)/NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome pathway, which is involved in diabetic nephropathy (DN) pathogenesis. The currently available oral anti-diabetic treatments have been insufficient to halt DN development and progression. Therefore, this work aimed to assess the renoprotective effect of the natural compound 6-gingerol (GR) either alone or in combination with metformin (MET) in high-fat diet/streptozotocin-induced DN in rats. The proposed molecular mechanisms were also investigated.

METHODS

Oral gavage of 6-gingerol (100 mg/kg) and metformin (300 mg/kg) were administered to rats daily for eight weeks. MiRNA-146a, miRNA-223, TLR4, TRAF6, nuclear factor-kappa B (NF-κB) (p65), NLRP3, caspase-1, and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA expressions were measured using real-time PCR. ELISA was used to measure TLR4, TRAF6, NLRP3, caspase-1, tumor necrosis factor-alpha (TNF-α), and interleukin-1-beta (IL-1β) renal tissue levels. Renal tissue histopathology and immunohistochemical examination of fibronectin and NF-κB (p65) were performed.

RESULTS

6-Gingerol treatment significantly reduced kidney tissue damage and fibrosis. 6-Gingerol up-regulated miRNA-146a and miRNA-223 and reduced TLR4, TRAF6, NF-κB (p65), NLRP3, caspase-1, TNF-α, IL-1β, HIF-1α and fibronectin renal expressions. 6-Gingerol improved lipid profile and renal functions, attenuated renal hypertrophy, increased reduced glutathione, and decreased blood glucose and malondialdehyde levels. 6-Gingerol and metformin combination showed superior renoprotective effects than either alone.

CONCLUSION

6-Gingerol demonstrated a key protective role in DN by induction of miRNA-146a and miRNA-223 expression and inhibition of TLR4/TRAF6/NLRP3 inflammasome signaling. 6-Gingerol, a safe, affordable, and abundant natural compound, holds promise for use as an adjuvant therapy with metformin in diabetic patients to attenuate renal damage and stop the progression of DN.

Effects of Bosentan on Hypoxia, Inflammation and Oxidative Stress in Experimental Blunt Thoracic Trauma Model

Background and Objectives: In this study, we aimed to investigate the effects of bosentan, an endothelin receptor antagonist, on endothelin-1 (ET-1), hypoxia-inducible factor-1 (HIF-1), nuclear factor-kappa B (NF-κB), and tumor necrosis factor (TNF)-α as inflammation markers, pro-oxidant antioxidant balance (PAB), and total antioxidant capacity (TAC) levels as oxidative stress parameters in lung tissues of rats in an experimental model of pulmonary contusion (PC) induced by blunt thoracic trauma. Materials and Methods: Thirty-seven male Sprague-Dawley rats were divided into five groups. C: The control group (n = 6) consisted of unprocessed and untreated rats. PC3 (n = 8) underwent 3 days of PC. PC-B3 (n = 8) received 100 mg/kg bosentan and was given orally once a day for 3 days. The PC7 group (n = 7) underwent 7 days of PC, and PC-B7 (n = 8) received 100 mg/kg bosentan and was given orally once a day for 7 days. Results: ET-1, NF-κB, TNF-α, HIF-1α, and PAB levels were higher, while TAC activity was lower in all groups compared with the control (p < 0.05). There was no significant difference in ET-1 and TNF-α levels between the PC-B3 and PC-B7 groups and the control group (p < 0.05), while NF-κB, HIF-1α, and PAB levels were still higher in both the PC-B3 and PC-B7 groups than in the control group. Bosentan decreased ET-1, NF-κB, TNF-α, HIF-1α, and PAB and increased TAC levels in comparison to the nontreated groups (p < 0.05). Conclusions: Bosentan decreased the severity of oxidative stress in the lungs and reduced the inflammatory reaction in rats with PC induced by blunt thoracic trauma. This suggests that bosentan may have protective effects on lung injury mechanisms by reducing hypoxia, inflammation, and oxidative stress. If supported by similar studies, bosentan can be used in both pulmonary and emergency clinics to reduce ischemic complications, inflammation, and oxidative stress in some diseases that may be accompanied by ischemia.

The Role of PTEN in Chemoresistance Mediated by the HIF-1α/YY1 Axis in Pediatric Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Current chemotherapy treatment regimens have improved survival rates to approximately 80%; however, resistance development remains the primary cause of treatment failure, affecting around 20% of cases. Some studies indicate that loss of the phosphatase and tensin homolog (PTEN) leads to deregulation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, increasing the expression of proteins involved in chemoresistance. PTEN loss results in deregulation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and induces hypoxia-inducible factor 1-alpha (HIF-1α) expression in various cancers. Additionally, it triggers upregulation of the Yin Yang 1 (YY1) transcription factor, leading to chemoresistance mediated by glycoprotein p-170 (Gp-170). The aim of this study was to investigate the role of the PTEN/NF-κB axis in YY1 regulation via HIF-1α and its involvement in ALL. A PTEN inhibitor was administered in RS4;11 cells, followed by the evaluation of PTEN, NF-κB, HIF-1α, YY1, and Gp-170 expression, along with chemoresistance assessment. PTEN, HIF-1α, and YY1 expression levels were assessed in the peripheral blood mononuclear cells (PBMC) from pediatric ALL patients. The results reveal that the inhibition of PTEN activity significantly increases the expression of pAkt and NF-κB, which is consistent with the increase in the expression of HIF-1α and YY1 in RS4;11 cells. In turn, this inhibition increases the expression of the glycoprotein Gp-170, affecting doxorubicin accumulation in the cells treated with the inhibitor. Samples from pediatric ALL patients exhibit PTEN expression and higher HIF-1α and YY1 expression compared to controls. PTEN/Akt/NF-κB axis plays a critical role in the regulation of YY1 through HIF-1α, and this mechanism contributes to Gp-170-mediated chemoresistance in pediatric ALL.

Changes in the Expression of Genes Regulating the Response to Hypoxia, Inflammation, Cell Cycle, Apoptosis, and Epithelial Barrier Functioning during Colitis-Associated Colorectal Cancer Depend on Individual Hypoxia Tolerance

One of the factors contributing to colorectal cancer (CRC) development is inflammation, which is mostly hypoxia-associated. This study aimed to characterize the morphological and molecular biological features of colon tumors in mice that were tolerant and susceptible to hypoxia based on colitis-associated CRC (CAC). Hypoxia tolerance was assessed through a gasping time evaluation in a decompression chamber. One month later, the animals were experimentally modeled for colitis-associated CRC by intraperitoneal azoxymethane administration and three dextran sulfate sodium consumption cycles. The incidence of tumor development in the distal colon in the susceptible to hypoxia mice was two times higher and all tumors (100%) were represented by adenocarcinomas, while in the tolerant mice, only 14% were adenocarcinomas and 86% were glandular intraepithelial neoplasia. The tumor area assessed on serially stepped sections was statistically significantly higher in the susceptible animals. The number of macrophages, CD3-CD19+, CD3+CD4+, and NK cells in tumors did not differ between animals; however, the number of CD3+CD8+ and vimentin+ cells was higher in the susceptible mice. Changes in the expression of genes regulating the response to hypoxia, inflammation, cell cycle, apoptosis, and epithelial barrier functioning in tumors and the peritumoral area depended on the initial mouse's hypoxia tolerance, which should be taken into account for new CAC diagnostics and treatment approaches development.

Primary Protection of Diosmin Against Doxorubicin Cardiotoxicity via Inhibiting Oxido-Inflammatory Stress and Apoptosis in Rats

Doxorubicin (DOX) is the cornerstone of chemotherapy. However, it has dose-dependent cardiotoxic events that limit its clinical use. This study was intended to investigate the efficiency of DOX as an anti-cancer against the MCF-7 cell line in the presence of diosmin (DIO) and to appraise the protective impact of DIO against DOX cardiotoxicity in vivo. In vitro study was carried out to establish the conservation of DOX cytotoxicity in the presence of DIO. In vivo study was conducted on 42 adult female Wistar rats that were equally allocated into 6 groups; control, DIO (100 mg/kg), DIO (200 mg/kg), DOX (20 mg/kg, single dose i.p.), DIO (100 mg/kg) + DOX, received DIO orally (100 mg/kg) for 30 days, then administrated with a single dose of DOX and DIO (200 mg/kg) + DOX, received DIO orally (200 mg/kg) for 30 days, then administrated with DOX. In vitro study showed preservation of cytotoxic activity of DOX on MCF-7 in the presence of DIO. In vivo study indicated that DOX altered electrocardiograph (ECG) parameters. Also, it yielded a significant rise in CK-MB, cTnT and LDH serum levels and cardiac contents of MDA, IL-1β; paralleled by a significant drop in cardiac IL-10 and SOD. Moreover, significant upregulation of Bax, TNF-α, and HIF-1α, in concomitant with significant downregulation of Bcl-2 mRNA in cardiac tissue have been recorded in the DOX group. Furthermore, histopathological description of cardiac tissues showed that DOX alters normal cardiac histoarchitecture. On the opposite side, DIO pretreatment could ameliorate ECG parameters, suppress IL-1β and enhanceIL-10, promote activity of SOD and repress MDA. Additionally, downregulation of Bax, TNF-α, HIF-1α and upregulation of Bcl-2 have been demonstrated in DIO-pretreated rats. Furthermore, the histopathological examination of cardiac tissues illustrated that DIO had a favorable impact on the protection of heart histoarchitecture. DIO is suggested for protection against acute cardiotoxicity caused by DOX without affecting antitumor activity.

The hypoxia response pathway in the Antarctic fish Notothenia coriiceps is functional despite a poly Q/E insertion mutation in HIF-1α

Antarctic notothenioid fishes, inhabiting the oxygen-rich Southern Ocean, possess a polyglutamine and glutamic acid (poly Q/E) insertion mutation in the master transcriptional regulator of oxygen homeostasis, hypoxia- inducible factor-1α (HIF-1α). To determine if this mutation impairs the ability of HIF-1 to regulate gene expression in response to hypoxia, we exposed Notothenia coriiceps, with a poly Q/E insertion mutation in HIF-1α that is 9 amino acids long, to hypoxia (2.3 mg L-1 O2) or normoxia (10 mg L -1 O2) for 12 h. Heart ventricles, brain, liver, and gill tissue were harvested and changes in gene expression quantified using RNA sequencing. Levels of glycogen and lactate were also quantified to determine if anaerobic metabolism increases in response to hypoxia. Exposure to hypoxia resulted in 818 unique differentially expressed genes (DEGs) in liver tissue of N. coriiceps. Many hypoxic genes were induced, including ones involved in the MAP kinase and FoxO pathways, glycolytic metabolism, and vascular remodeling. In contrast, there were fewer than 104 unique DEGs in each of the other tissues sampled. Lactate levels significantly increased in liver in response to hypoxia, indicating that anaerobic metabolism increases in response to hypoxia in this tissue. Overall, our results indicate that the hypoxia response pathway is functional in N. coriiceps despite a poly Q/E mutation in HIF-1α, and confirm that Antarctic fishes are capable of altering gene expression in response to hypoxia.

The transcription factor BMI1 increases hypoxic signaling in oral cavity epithelia

The tongue epithelium is maintained by a proliferative basal layer. This layer contains long-lived stem cells (SCs), which produce progeny cells that move up to the surface as they differentiate. B-lymphoma Mo-MLV insertion region 1 (BMI1), a protein in mammalian Polycomb Repressive Complex 1 (PRC1) and a biomarker of oral squamous cell carcinoma, is expressed in almost all basal epithelial SCs of the tongue, and single, Bmi1-labelled SCs give rise to cells in all epithelial layers. We previously developed a transgenic mouse model (KrTB) containing a doxycycline- (dox) controlled, Tet-responsive element system to selectively overexpress Bmi1 in the tongue basal epithelial SCs. Here, we used this model to assess BMI1 actions in tongue epithelia. Genome-wide transcriptomics revealed increased levels of transcripts involved in the cellular response to hypoxia in Bmi1-overexpressing (KrTB+DOX) oral epithelia even though these mice were not subjected to hypoxia conditions. Ectopic Bmi1 expression in tongue epithelia increased the levels of hypoxia inducible factor-1 alpha (HIF1α) and HIF1α targets linked to metabolic reprogramming during hypoxia. We used chromatin immunoprecipitation (ChIP) to demonstrate that Bmi1 associates with the promoters of HIF1A and HIF1A-activator RELA (p65) in tongue epithelia. We also detected increased SC proliferation and oxidative stress in Bmi1-overexpressing tongue epithelia. Finally, using a human oral keratinocyte line (OKF6-TERT1R), we showed that ectopic BMI1 overexpression decreases the oxygen consumption rate while increasing the extracellular acidification rate, indicative of elevated glycolysis. Thus, our data demonstrate that high BMI1 expression drives hypoxic signaling, including metabolic reprogramming, in normal oral cavity epithelia.

Metabolic Adaptations and Functional Activity of Macrophages in Homeostasis and Inflammation

In recent years, the role of cellular metabolism in immunity has come into the focus of many studies. These processes form a basis for the maintenance of tissue integrity and homeostasis, as well as represent an integral part of the immune response, in particular, inflammation. Metabolic adaptations not only ensure energy supply for immune response, but also affect the functions of immune cells by controlling transcriptional and post-transcriptional programs. Studying the immune cell metabolism facilitates the search for new treatment approaches, especially for metabolic disorders. Macrophages, innate immune cells, are characterized by a high functional plasticity and play a key role in homeostasis and inflammation. Depending on the phenotype and origin, they can either perform various regulatory functions or promote inflammation state, thus exacerbating the pathological condition. Furthermore, their adaptations to the tissue-specific microenvironment influence the intensity and type of immune response. The review examines the effect of metabolic reprogramming in macrophages on the functional activity of these cells and their polarization. The role of immunometabolic adaptations of myeloid cells in tissue homeostasis and in various pathological processes in the context of inflammatory and metabolic diseases is specifically discussed. Finally, modulation of the macrophage metabolism-related mechanisms reviewed as a potential therapeutic approach.

Whole blood coagulation in an ex vivo thrombus is sufficient to induce clot neutrophils to adopt a myeloid-derived suppressor cell signature and shed soluble Lox-1

BACKGROUND

Blood clots are living tissues that release inflammatory mediators including IL-8/CXCL8 and MCP-1/CCL2. A deeper understanding of blood clots is needed to develop new therapies for prothrombotic disease states and regenerative medicine.

OBJECTIVES

To identify a common transcriptional shift in cultured blood clot leukocytes.

METHODS

Differential gene expression of whole blood and cultured clots (4 hours at 37 °C) was assessed by RNA sequencing (RNAseq), reverse transcriptase-polymerase chain reaction, proteomics, and histology (23 diverse healthy human donors). Cultured clot serum bioactivity was tested in endothelial barrier functional assays.

RESULTS

All cultured clots developed a polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) signature, including up-regulation of OLR1 (mRNA encoding lectin-like oxidized low-density lipoprotein receptor 1 [Lox-1]), IL-8/CXCL8, CXCL2, CCL2, IL10, IL1A, SPP1, TREM1, and DUSP4/MKP. Lipopolysaccharide enhanced PMN-MDSC gene expression and specifically induced a type II interferon response with IL-6 production. Lox-1 was specifically expressed by cultured clot CD15+ neutrophils. Cultured clot neutrophils, but not activated platelets, shed copious amounts of soluble Lox-1 (sLox-1) with a donor-dependent amplitude. sLox-1 shedding was enhanced by phorbol ester and suppressed by heparin and by beta-glycerol phosphate, a phosphatase inhibitor. Cultured clot serum significantly enhanced endothelial cell monolayer barrier function, consistent with a proresolving bioactivity.

CONCLUSION

This study suggests that PMN-MDSC activation is part of the innate immune response to coagulation which may have a protective role in inflammation. The cultured blood clot is an innovative thrombus model that can be used to study both sterile and nonsterile inflammatory states and could be used as a personalized medicine tool for drug screening.

Hyperbaric Oxygen Reduces Oxidative Stress Impairment and DNA Damage and Simultaneously Increases HIF-1α in Ischemia-Reperfusion Acute Kidney Injury

The central exacerbating factor in the pathophysiology of ischemic-reperfusion acute kidney injury (AKI) is oxidative stress. Lipid peroxidation and DNA damage in ischemia are accompanied by the formation of 3-nitrotyrosine, a biomarker for oxidative damage. DNA double-strand breaks (DSBs) may also be a result of postischemic AKI. γH2AX(S139) histone has been identified as a potentially useful biomarker of DNA DSBs. On the other hand, hypoxia-inducible factor (HIF) is the "master switch" for hypoxic adaptation in cells and tissues. The aim of this research was to evaluate the influence of hyperbaric oxygen (HBO) preconditioning on antioxidant capacity estimated by FRAP (ferric reducing antioxidant power) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assay, as well as on oxidative stress parameter 3-nitrotyrosine, and to assess its effects on γH2AX(S139), HIF-1α, and nuclear factor-κB (NF-κB) expression, in an experimental model of postischemic AKI induced in spontaneously hypertensive rats. The animals were divided randomly into three experimental groups: sham-operated rats (SHAM, n = 6), rats with induced postischemic AKI (AKI, n = 6), and group exposed to HBO preconditioning before AKI induction (AKI + HBO, n = 6). A significant improvement in the estimated glomerular filtration rate, eGFR, in AKI + HBO group (p < 0.05 vs. AKI group) was accompanied with a significant increase in plasma antioxidant capacity estimated by FRAP (p < 0.05 vs. SHAM group) and a reduced immunohistochemical expression of 3-nitrotyrosine and γH2AX(S139). Also, HBO pretreatment significantly increased HIF-1α expression (p < 0.001 vs. AKI group), estimated by Western blot and immunohistochemical analysis in kidney tissue, and decreased immunohistochemical NF-κB renal expression (p < 0.01). Taking all of these results together, we may conclude that HBO preconditioning has beneficial effects on acute kidney injury induced in spontaneously hypertensive rats.

Chemokine Fractalkine and Non-Obstructive Coronary Artery Disease-Is There a Link?

Non-obstructive coronary artery disease (NO-CAD) constitutes a heterogeneous group of conditions collectively characterized by less than 50% narrowing in at least one major coronary artery with a fractional flow reserve (FFR) of ≤0.80 observed in coronary angiography. The pathogenesis and progression of NO-CAD are still not fully understood, however, inflammatory processes, particularly atherosclerosis and microvascular dysfunction are known to play a major role in it. Chemokine fractalkine (FKN/CX3CL1) is inherently linked to these processes. FKN/CX3CL1 functions predominantly as a chemoattractant for immune cells, facilitating their transmigration through the vessel wall and inhibiting their apoptosis. Its concentrations correlate positively with major cardiovascular risk factors. Moreover, promising preliminary results have shown that FKN/CX3CL1 receptor inhibitor (KAND567) administered in the population of patients with ST-elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI), inhibits the adverse reaction of the immune system that causes hyperinflammation. Whereas the link between FKN/CX3CL1 and NO-CAD appears evident, further studies are necessary to unveil this complex relationship. In this review, we critically overview the current data on FKN/CX3CL1 in the context of NO-CAD and present the novel clinical implications of the unique structure and function of FKN/CX3CL1 as a compound which distinctively contributes to the pathomechanism of this condition.

The role of oxygen tension in cell fate and regenerative medicine: implications of hypoxia/hyperoxia and free radicals

Oxygen pressure plays an integral role in regulating various aspects of cellular biology. Cell metabolism, proliferation, morphology, senescence, metastasis, and angiogenesis are some instances that are affected by different tensions of oxygen. Hyperoxia or high oxygen concentration, enforces the production of reactive oxygen species (ROS) that disturbs physiological homeostasis, and consequently, in the absence of antioxidants, cells and tissues are directed to an undesired fate. On the other side, hypoxia or low oxygen concentration, impacts cell metabolism and fate strongly through inducing changes in the expression level of specific genes. Thus, understanding the precise mechanism and the extent of the implication of oxygen tension and ROS in biological events is crucial to maintaining the desired cell and tissue function for application in regenerative medicine strategies. Herein, a comprehensive literature review has been performed to find out the impacts of oxygen tensions on the various behaviors of cells or tissues.

Critical and distinct roles of cell type-specific NF-κB2 in lung cancer

Different from the well-studied canonical NF-κB member RelA, the role of the noncanonical NF-κB member NF-κB2 in solid tumors, and lung cancer in particular, is poorly understood. Here we report that in contrast to the tumor-promoting role of RelA, NF-κB2 intrinsic to lung epithelial and tumor cells had no marked effect on lung tumorigenesis and progression. On the other hand, NF-κB2 limited dendritic cell number and activation in the lung but protected lung macrophages and drove them to promote lung cancer through controlling activation of noncanonical and canonical NF-κB, respectively. NF-κB2 was also required for B cell maintenance and T cell activation. The antitumor activity of lymphocyte NF-κB2 was dominated by the protumor function of myeloid NF-κB2; thus, NF-κB2 has an overall tumor-promoting activity. These studies reveal a cell type-dependent role for NF-κB2 in lung cancer and help understand the complexity of NF-κB action and lung cancer pathogenesis for better design of NF-κB-targeted therapy against this deadliest cancer.

Combinatorial regulation by ERK1/2 and CK1δ protein kinases leads to HIF-1α association with microtubules and facilitates its symmetrical distribution during mitosis

Hypoxia-inducible factor-1 (HIF-1) is the key transcriptional mediator of the cellular response to hypoxia and is also involved in cancer progression. Regulation of its oxygen-sensitive HIF-1α subunit involves post-translational modifications that control its stability, subcellular localization, and activity. We have previously reported that phosphorylation of the HIF-1α C-terminal domain by ERK1/2 promotes HIF-1α nuclear accumulation and stimulates HIF-1 activity while lack of this modification triggers HIF-1α nuclear export and its association with mitochondria. On the other hand, modification of the N-terminal domain of HIF-1α by CK1δ impairs HIF-1 activity by obstructing the formation of a HIF-1α/ARNT heterodimer. Investigation of these two antagonistic events by expressing double phospho-site mutants in HIF1A-/- cells under hypoxia revealed independent and additive phosphorylation effects that can create a gradient of HIF-1α subcellular localization and transcriptional activity. Furthermore, modification by CK1δ caused mitochondrial release of the non-nuclear HIF-1α form and binding to microtubules via its N-terminal domain. In agreement, endogenous HIF-1α could be shown to co-localize with mitotic spindle microtubules and interact with tubulin, both of which were inhibited by CK1δ silencing or inhibition. Moreover, CK1δ expression was necessary for equal partitioning of mother cell-produced HIF-1α to the daughter cell nuclei at the end of mitosis. Overall, our results suggest that phosphorylation by CK1δ stimulates the association of non-nuclear HIF-1α with microtubules, which may serve as a means to establish a symmetric distribution of HIF-1α during cell division under low oxygen conditions.

Expression and regulation of HIF-1a in hypoxic pulmonary hypertension: Focus on pathological mechanism and Pharmacological Treatment

Hypoxia inducible factor-1(HIF-1), a heterodimeric transcription factor, is composed of two subunits (HIF-1α and HIF-1β). It is considered as an important transcription factor for regulating oxygen changes in hypoxic environment, which can regulate the expression of various hypoxia-related target genes and play a role in acute and chronic hypoxia pulmonary vascular reactions. In this paper, the function and mechanism of HIF-1a expression and regulation in hypoxic pulmonary hypertension (HPH) were reviewed, and current candidate schemes for treating pulmonary hypertension by using HIF-1a as the target were introduced, so as to provide reference for studying the pathogenesis of HPH and screening effective treatment methods.

M. tb Rv0927c suppresses the activation of HIF-1α pathway through VHL-mediated ubiquitination and NF-κB/COX-2 pathway to enhance mycobacteria survival

Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, employs various effector proteins to target and modulate host defenses. Our previous study showed that M. tuberculosis protein Rv0927c can promote the survival of intracellular mycobacteria, but the underlying mechanisms remain poorly understood. Here, we found that Rv0927c inhibited Mycobacterium smegmatis (M. smegmatis) induced hypoxia-inducible factor-1α (HIF-1α) activation in macrophages, and HIF-1α is required for Rv0927c to promote mycobacteria survival. Western blot analysis showed that Rv0927c promoted the proteasomal degradation of HIF-1α via Von Hippel-Lindau (VHL)-mediated ubiquitination and inhibited the nuclear localization of HIF-1α through the NF-κB/COX-2 pathway, thereby suppressing HIF-1α pathway activation. Furthermore, Rv0927c suppressed the host glycolytic metabolism, which is known to be regulated by HIF-1α and depended on the glycolysis process to promote mycobacterial survival. Our findings provide evidence that Rv0927c inhibits the activation of HIF-1α pathway, allowing pathogens to evade host immune responses, suggesting that targeting Rv0927c or HIF-1α might be a potential anti-tuberculosis therapy.

Honokiol Attenuates Choroidal Neovascularization by Inhibiting the Hypoxia-Inducible Factor-α/Vascular Endothelial Growth Factor Axis via Nuclear Transcription Factor-Kappa B Activation

PURPOSE

Honokiol is a lignan isolated from Magnolia officinalis and exhibits anti-angiogenic properties. This study was conducted to investigate the role of honokiol in choroidal neovascularization.

METHODS

C57BL/6 mice were treated with honokiol at 10-20 mg/kg by daily intraperitoneal injection from day 1 to 6 after laser photocoagulation. ARPE-19 cells were cultured under hypoxic conditions with or without the presence of honokiol. After laser photocoagulation and honokiol treatment, hematoxylin and eosin staining, immunofluorescence and fundus fluorescein angiography were used to analyze the effect of honokiol on choroidal neovascularization formation. Quantitative real-time PCR, western blot, enzyme-linked immunosorbent assay, immunofluorescence, luciferase assay, and chromatin immunoprecipitation were performed to explore the mechanism of honokiol in the pathological process of choroidal neovascularization. Finally, the role of honokiol on the human choroidal vascular endothelial cells was detected by using 5-ethynyl-20-deoxyuridine assay, Transwell and Tube formation assays.

RESULTS

The results of hematoxylin and eosin staining and immunofluorescence suggested that honokiol reduced the thickness, length, and area of choroidal neovascularization lesions in laser-induced choroidal neovascularization mouse model. Fundus fluorescein angiography showed that choroidal neovascularization leakage was reduced in honokiol group and the concentration of 20 mg/kg showed better effects. Mechanism studies have shown that honokiol exerted inhibitory effects on choroidal neovascularization by inactivating hypoxia-inducible factor-1α/vascular endothelial growth factor axis through the nuclear transcription factor-kappa B signaling pathway. The same results were obtained in ARPE-19 cells under hypoxic conditions. Furthermore, the conditional medium of retinal pigmented epithelial cells promoted the proliferation, migration, and tube formation of human choroidal vascular endothelial cells, while honokiol reversed these.

CONCLUSION

We demonstrated that honokiol attenuated choroidal neovascularization formation by inactivating the hypoxia-inducible factor-1α/vascular endothelial growth factor axis through nuclear transcription factor-kappa B signaling pathway.

Effect of iron administration on the aortic iron content and vascular calcification in phosphorus-loaded chronic kidney disease rats

BACKGROUND

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with chronic kidney disease (CKD) and could be related to oxidative stress. Vascular calcification (VC) has been established as a critical risk factor for accelerated CVD. In CKD, phosphorus (Pi), iron (Fe) and Nrf2 are modulators of VC and important agonists and antagonists of oxidative stress. The aim of this study was to determine whether Fe administration, which is commonly used to treat renal anemia, affects aortic Fe overload and VC, and whether Nrf2 and its related genes, ferritin H and HIF-1α, are involved in the development of VC.

METHODS

A CKD model was created in rats by administering adenine and simultaneously feeding a high-Pi diet. In addition to control and CKD rats without Fe administration (No-Fe group), Fe was administered orally (PO-Fe group) or intraperitoneally (IP-Fe group) to CKD animals to clarify the effects of Fe administration on the aortic Fe and calcium (Ca) contents and the involvement of Nrf2 and its induced antioxidative proteins, ferritin H and HIF-1α, in VC.

RESULTS

The aortic Fe content increased significantly in the IP-Fe group, which was closely correlated with liver HAMP (hepcidin) expression in all animals. Fe administration had no significant effect on the aortic Ca and Pi contents regardless of the route of Fe administration. The aortic mRNA level of Nrf2 was significantly increased in the IP-Fe group and correlated with serum Pi levels and aortic Fe contents, which could respond to oxidative stress. Notably, the mRNA level of Nrf2 was also significantly correlated with the mRNA levels of ferritin H and HIF-1α. Since we could not measure Nrf2 protein levels in this study, we confirmed the upregulation of HMOX1 and NQO1 mRNA expression in parallel with Nrf2 mRNA.

CONCLUSION

Parenteral Fe administration increased aortic Fe in parallel with the liver HAMP mRNA level but did not affect VC. Aortic Nrf2 mRNA levels correlated significantly with aortic Fe and serum Pi levels and with aortic mRNA levels of ferritin H and HIF-1α as well as HMOX1 and NQO1.