HIF-1: mediator of physiological and pathophysiological responses to hypoxia

Topical Anti-ulcerogenic Effect of the Beta-adrenergic Blockers on Diabetic Foot Ulcers: Recent Advances and Future Prospectives

BACKGROUND

Patients with diabetes suffer from major complications like Diabetic Retinopathy, Diabetic Coronary Artery Disease, and Diabetic Foot ulcers (DFUs). Diabetes complications are a group of ailments whose recovery time is especially delayed, irrespective of the underlying reason. The longer duration of wound healing enhances the probability of problems like sepsis and amputation. The delayed healing makes it more critical for research focus. By understanding the molecular pathogenesis of diabetic wounds, it is quite easy to target the molecules involved in the healing of wounds. Recent research on beta-adrenergic blocking drugs has revealed that these classes of drugs possess therapeutic potential in the healing of DFUs. However, because the order of events in defective healing is adequately defined, it is possible to recognize moieties that are currently in the market that are recognized to aim at one or several identified molecular processes.

OBJECTIVE

The aim of this study was to explore some molecules with different therapeutic categories that have demonstrated favorable effects in improving diabetic wound healing, also called the repurposing of drugs.

METHOD

Various databases like PubMed/Medline, Google Scholar and Web of Science (WoS) of all English language articles were searched, and relevant information was collected regarding the role of beta-adrenergic blockers in diabetic wounds or diabetic foot ulcers (DFUs) using the relevant keywords for the literature review.

RESULT

The potential beta-blocking agents and their mechanism of action in diabetic foot ulcers were studied, and it was found that these drugs have a profound effect on diabetic foot ulcer healing as per reported literatures.

CONCLUSION

There is a need to move forward from preclinical studies to clinical studies to analyze clinical findings to determine the effectiveness and safety of some beta-antagonists in diabetic foot ulcer treatment.

Indirect biomarkers of blood doping: A systematic review

The detection of blood doping represents a current major issue in sports and an ongoing challenge for antidoping research. Initially focusing on direct detection methods to identify a banned substance or its metabolites, the antidoping effort has been progressively complemented by indirect approaches. The longitudinal and individual monitoring of specific biomarkers aims to identify nonphysiological variations that may be related to doping practices. From this perspective, the identification of markers sensitive to erythropoiesis alteration is key in the screening of blood doping. The current Athlete Biological Passport implemented since 2009 is composed of 14 variables (including two primary markers, i.e., hemoglobin concentration and OFF score) for the hematological module to be used for indirect detection of blood doping. Nevertheless, research has continually proposed and investigated new markers sensitive to an alteration of the erythropoietic cascade and specific to blood doping. If multiple early markers have been identified (at the transcriptomic level) or developed directly in a diagnostics' kit (at a proteomic level), other target variables at the end of the erythropoietic process (linked with the red blood cell functions) may strengthen the hematological module in the future. Therefore, this review aims to provide a global systematic overview of the biomarkers considered to date in the indirect investigation of blood doping.

Klotho: a potential therapeutic target in aging and neurodegeneration beyond chronic kidney disease-a comprehensive review from the ERA CKD-MBD working group

Klotho, a multifunctional protein, acts as a co-receptor in fibroblast growth factor 23 and exerts its impact through various molecular pathways, including Wnt, hypoxia-inducible factor and insulin-like growth factor 1 pathways. The physiological significance of Klotho is the regulation of vitamin D and phosphate metabolism as well as serving as a vital component in aging and neurodegeneration. The role of Klotho in aging and neurodegeneration in particular has gained considerable attention. In this narrative review we highlight several key insights into the molecular basis and physiological function of Klotho and synthesize current research on the role of Klotho in neurodegeneration and aging. Klotho deficiency was associated with cognitive impairment, reduced growth, diminished longevity and the development of age-related diseases in vivo. Serum Klotho levels showed a decline in individuals with advanced age and those affected by chronic kidney disease, establishing its potential diagnostic significance. Additionally, multiple medications have been demonstrated to influence Klotho levels. Therefore, this comprehensive review suggests that Klotho could open the door to novel interventions aimed at addressing the challenges of aging and neurodegenerative disorders.

Detection of Hypoxia in 2D and 3D Cell Culture Systems Using Genetically Encoded Fluorescent Hypoxia Sensors

In vivo oxygen availability varies widely between cellular microenvironments, depending on the tissue of origin and its cellular niche. It has long been known that too high or too low oxygen concentrations can act as a biological stressor. Thus, the precise control of oxygen availability should be a consideration for cell culture optimization, especially in the field of three-dimensional (3D) cell culture. In this chapter, we describe a system for visualizing oxygen limitations at a cellular level using human adipose tissue-derived mesenchymal stem cells (hAD-MSCs) that were genetically modified to express a fluorescent hypoxia sensor. This sensor can detect the activation of hypoxia-induced factors (HIF) transcription factors that lead to the expression of the oxygen-independent fluorescent protein, UnaG, at low oxygen concentrations. The response of these hypoxia reporter cells can be evaluated in two-dimensional (2D) and 3D cultivation platforms during exposure to hypoxia (1% O2) and normoxia (21% O2) using fluorescence microscopy and flow cytometry. We show that hypoxia reporter MSCs exhibit a hypoxia-induced fluorescence signal in both 2D and 3D cultivation platforms with fast decay kinetics after reoxygenation, rendering it a valuable tool for studying the cellular microenvironment and regenerative potential of hAD-MSCs in an in vivo-like setting.

Recent Developments in Gene Therapy for Neovascular Age-Related Macular Degeneration: A Review

Age-related macular degeneration (AMD) is a complex and multifactorial disease and a leading cause of irreversible blindness in the elderly population. The anti-vascular endothelial growth factor (anti-VEGF) therapy has revolutionized the management and prognosis of neovascular AMD (nAMD) and is currently the standard of care for this disease. However, patients are required to receive repeated injections, imposing substantial social and economic burdens. The implementation of gene therapy methods to achieve sustained delivery of various therapeutic proteins holds the promise of a single treatment that could ameliorate the treatment challenges associated with chronic intravitreal therapy, and potentially improve visual outcomes. Several early-phase trials are currently underway, evaluating the safety and efficacy of gene therapy for nAMD; however, areas of controversy persist, including the therapeutic target, route of administration, and potential safety issues. In this review, we assess the evolution of gene therapy for nAMD and summarize several preclinical and early-stage clinical trials, exploring challenges and future directions.

The effects of maternal smoking on fetal cranial development. Findings from routine midtrimester sonographic anomaly screening

The aim of this study was to assess the effect of continued smoking before and during pregnancy on mid-trimester fetal head development. A total of 250 pregnant women enrolled in the study. All participants were confirmed to be smokers or non-smokers by verifying breath carbon monoxide readings. Biparietal diameter (BPD), head circumference (HC), lateral ventricle (LV), and cisterna magna (CM) were evaluated by ultrasound between 20-22 weeks of pregnancy. Gender and gestational age-adjusted BPD z- scores were not statistically different between smokers and non-smokers (-0.75 ± 1.6 vs -0.51 ± 1, p = .3). HC measurements and z- scores were significantly lower in the smoking group than in the non-smoking groups (183.38 ± 14.56 vs. 189.28 ± 12.53, p = .003, 0.18 ± 1.39 multiple of median (MoM) vs. 0.56 ± 0.92, respectively, p = .023). At linear regression analysis, maternal smoking was the only independent factor associated with fetal HC z score (p = .041). In conclusion, continued smoking during pregnancy reduces fetal HC and has no effect on BPD, LV, or CM measurements at mid-gestation.IMPACT STATEMENTWhat is already known on this subject? Smoking during pregnancy is one of the most common environmental factors affecting fetal and neonatal growth and well-being. Despite the well-known effects of smoking on somatic growth, current studies have shown that it selectively affects some parts of the fetal brain, even in appropriately growing fetuses.What do the results of this study add? Continued smoking during pregnancy reduces fetal HC and has no effect on BPD, LV or CM measurements at mid-gestation. Since smoking is well known for its early and late childhood behavioral and neurological consequences, smaller mid-trimester fetal HC measurements should bring maternal smoking to mind as one of the potentially reversible causes.What are the implications of these findings for clinical practice and/or further research? The harmful effects of smoking start before the third trimester and antenatal counseling should be started early in the gestation. Every effort should be made to quit smoking before or early in pregnancy.

Screening of potential key ferroptosis-related genes in Chronic Obstructive Pulmonary Disease

PURPOSE

Ferroptosis plays essential roles in the development of COPD. We aim to identify the potential ferroptosis-related genes of COPD through bioinformatics analysis.

METHODS

The RNA expression profile dataset GSE148004 was obtained from the GEO database. The ferroptosis-related genes were obtained from the FerrDb database. The potential differentially expressed ferroptosis-related genes of COPD were screened by R software. Then, protein-protein interactions (PPI), correlation analysis, gene-ontology (GO) enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were applied for the differentially expressed ferroptosis-related genes. Finally, hub gene-microRNA(miRNA), hug gene-transcription factor interaction networks were constructed by miRTarBase v8.0 and JASPAR respectively, and hub gene drugs were predicted by the Enrichr database.

RESULTS

A total of 41 differentially expressed ferroptosis-related genes (22 up-regulated genes and 19 down-regulated genes) were identified between 7 COPD patients and 9 healthy controls. The PPI results demonstrated that these ferroptosis-related genes interacted with each other. The GO and KEGG enrichment analyses of differentially expressed ferroptosis-related genes indicated several enriched terms related to ferroptosis, central carbon metabolism in cancer, and the HIF-1 signaling pathway. The crucial miRNAs and drugs associated with the top genes were identified.

CONCLUSION

We identified 41 potential ferroptosis-related genes in COPD through bioinformatics analysis. HIF1A, PPARG, and KRAS may affect the development of COPD by regulating ferroptosis. These results may expand our understanding of COPD and might be useful in the treatment of COPD.

Unexplained Causes of Glioma-Associated Epilepsies: A Review of Theories and an Area for Research

Approximately 30% of glioma patients are able to survive beyond one year postdiagnosis. And this short time is often overshadowed by glioma-associated epilepsy. This condition severely impairs the patient's quality of life and causes great suffering. The genetic, molecular and cellular mechanisms underlying tumour development and epileptogenesis remain incompletely understood, leading to numerous unanswered questions. The various types of gliomas, namely glioblastoma, astrocytoma and oligodendroglioma, demonstrate distinct seizure susceptibility and disease progression patterns. Patterns have been identified in the presence of IDH mutations and epilepsy, with tumour location in cortical regions, particularly the frontal lobe, showing a more frequent association with seizures. Altered expression of TP53, MGMT and VIM is frequently detected in tumour cells from individuals with epilepsy associated with glioma. However, understanding the pathogenesis of these modifications poses a challenge. Moreover, hypoxic effects induced by glioma and associated with the HIF-1a factor may have a significant impact on epileptogenesis, potentially resulting in epileptiform activity within neuronal networks. We additionally hypothesise about how the tumour may affect the functioning of neuronal ion channels and contribute to disruptions in the blood-brain barrier resulting in spontaneous depolarisations.

Hypoxia activates SREBP2 through Golgi disassembly in bone marrow-derived monocytes for enhanced tumor growth

Bone marrow-derived cells (BMDCs) infiltrate hypoxic tumors at a pre-angiogenic state and differentiate into mature macrophages, thereby inducing pro-tumorigenic immunity. A critical factor regulating this differentiation is activation of SREBP2-a well-known transcription factor participating in tumorigenesis progression-through unknown cellular mechanisms. Here, we show that hypoxia-induced Golgi disassembly and Golgi-ER fusion in monocytic myeloid cells result in nuclear translocation and activation of SREBP2 in a SCAP-independent manner. Notably, hypoxia-induced SREBP2 activation was only observed in an immature lineage of bone marrow-derived cells. Single-cell RNA-seq analysis revealed that SREBP2-mediated cholesterol biosynthesis was upregulated in HSCs and monocytes but not in macrophages in the hypoxic bone marrow niche. Moreover, inhibition of cholesterol biosynthesis impaired tumor growth through suppression of pro-tumorigenic immunity and angiogenesis. Thus, our findings indicate that Golgi-ER fusion regulates SREBP2-mediated metabolic alteration in lineage-specific BMDCs under hypoxia for tumor progression.

HIF-1α is positively associated with endometrial receptivity by regulating PKM2

PURPOSE

Numerous advancements have been introduced into the field of assisted reproductive technology (ART) in the past four decades. Nonetheless, implantation failure is still a key limiting step for a successful pregnancy. Building of endometrial receptivity (ER) is essential for successful implantation. However, the fundamental biological processes and mechanisms of ER remain elusive. Our study investigates the function of hypoxia inducible factor-1α (HIF-1α) during ER establishment and shed lights on the novel molecular mechanism by which HIF-1α regulates ER-related gene expression network.

METHODS

Levels of HIF-1α, homeobox A10 (HOXA10), insulin-like growth factor-binding protein 1 (IGFBP1), pyruvate kinase M2 (PKM2), and lactate dehydrogenase A (LDHA) in endometrial tissues were measured via real-time PCR, immunoblotting and immunohistochemistry. The correlation between HIF-1α and HOXA10, IGFBP1, PKM2, LDHA were analyzed separately. Ishikawa cells were treated with vector HIF-1α, HIF-1α-siRNA, and PKM2-siRNA. After transfection, the levels of HOXA10, IGFBP1, LDHA, and PKM2 were measured via real-time PCR and immunoblotting, and the lactate concentrations and cell migration of Ishikawa cells were measured.

RESULTS

Levels of HIF-1α, IGFBP1, HOXA10, LDHA, and PKM2 were significantly decreased in recurrent implantation failure (RIF) patients and levels of HOXA10, IGFBP1, PKM2, and LDHA were correlated with HIF-1α in endometrium. Then in a cellular model established by HIF-1α vector and HIF-1α-siRNA, the expression of HOXA10, IGFBP1, LDHA, PKM2, and lactate concentrations were dramatically upregulated and downregulated. And the expression of HOXA10, and IGFBP1 were dramatically decreased by PKM2-siRNA.

CONCLUSIONS

HIF-1α plays a crucial role in the building of ER through regulating glycolysis.

Role of SOX9 and Hif-1α expression in placentas of patients with HELLP

PURPOSE

In this study, we investigated the immunohistochemical staining of SRY-box transcription factor 9 (SOX9) and Hif-1α expression in placentas of pregnant woman with hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome.

METHODS

Placentas of 20 normotensive and 20 women with HELLP syndrome were processed for routine histological tissue processing. The biochemical and clinical parameters of patients were recorded. Placentas were stained with hematoxylin-eosin and SOX9 and Hif-1α immunostaining.

RESULTS

Normotensive placentas showed normal histology of placenta, however placentas of HELLP syndrome showed intense thrombosis, thinning of the villi membrane and vascular dilatation. In placentas of normotensive patients, SOX9 reaction was immunohistochemically negative, however placentas of HELLP group showed SOX9 expression in decidual cells, and syncytial regions of floating villi and inflammatory cells. In placentas of normotensive patients, Hif-1α reaction was mainly negative in vessels and connective tissue cells. Placentas of HELLP group showed increased Hif-1α expression in decidual cell and especially inflammatory cells in the maternal region.

CONCLUSIONS

Hif-1α and SOX9 proteins can be used as a marker to show severity of preeclampsia and regulation of cell proliferation and angiogenesis during placental development.

YAP nuclear translocation induced by HIF-1α prevents DNA damage under hypoxic conditions

Maladaptive repair of acute kidney injury (AKI) is associated with a high risk of developing chronic kidney disease deemed irremediable even in present days. When AKI arises from ischemia-reperfusion injury, hypoxia usually plays a major role. Although both hypoxia-inducible factor-1α (HIF-1α) and yes-associated protein (YAP) have been proven to promote renal cell survival under hypoxia, there is a lack of research that studies the crosstalk of the two and its effect on kidney repair. In studying the crosstalk, CoCl2 was used to create a mimetic hypoxic environment. Immunoprecipitation and proximity ligation assays were performed to verify protein interactions. The results show that HIF-1α interacts with YAP and promotes nuclear translocation of YAP at a high cell density under hypoxic conditions, suggesting HIF-1α serves as a direct carrier that enables YAP nuclear translocation. This is the first study to identify HIF-1α as a crucial pathway for YAP nuclear translocation under hypoxic conditions. Once translocated into a nucleus, YAP protects cells from DNA damage and apoptosis under hypoxic conditions. Since it is unlikely for YAP to translocate into a nucleus without HIF-1α, any treatment that fosters the crosstalk between the two holds the potential to improve cell recovery from hypoxic insults.

Extracellular Vesicles Derived From Hypoxia-Treated Human Adipose Stem Cells Increase Proliferation and Angiogenic Differentiation in Human Adipose Stem Cells

BACKGROUND

Adipose-derived stem cells (ADSCs) are crucial in cell-assisted lipotransfer (CAL). ADSC-derived exosomes could improve the survival of CAL. Almost all relevant research now ignores ADSCs in favor of studying the proangiogenic potential of extracellular vesicles (EVs) on human umbilical vein endothelial cells (HUVECs).

OBJECTIVES

Given the significance of ADSCs in CAL, the authors sought to verify that EVs from ADSCs under hypoxia treatment can enhance the angiogenic potential of ADSCs.

METHODS

EVs were harvested from human ADSCs (hADSCs) under normoxia and hypoxia. A Cell Counting Kit-8 (CCK-8) assay was used to measure the proliferation of hADSCs. By examining the expression of CD31, vascular endothelial growth factor receptor 2, and vascular endothelial growth factor, the pro-angiogenic differentiation potential was assessed. Moreover, a tube formation experiment was carried out to evaluate the pro-angiogenic differentiation potential.

RESULTS

Hypoxic EVs showed more significant pro-proliferative and pro-angiogenic potential. Angiogenesis was more vigorous in hADSCs treated with hypoxic EVs than in those treated with nomorxic EVs. The hADSCs treated with hypoxic EVs expressed higher angiogenic markers, according to real-time polymerase chain reaction (RT-PCR) and Western blot analysis, which revealed more angiogenic marker expression in hypoxic EV-treated hADSCs. The same result was demonstrated by tube formation on Matrigel in vitro.

CONCLUSIONS

Hypoxic EVs significantly increased the proliferation and angiogenic differentiation potential of hADSCs. Hypoxic EV-treated ADSCs may be beneficial to CAL and prevascularized tissue-engineered constructs.

In vitro and in vivo characterization of [64Cu][Cu(elesclomol)] as a novel theranostic agent for hypoxic solid tumors

PURPOSE

Hypoxic tumors are associated with therapy resistance and poor cancer prognosis, but methods to detect and counter tumor hypoxia remain insufficient. Our purpose was to investigate 64Cu(II)-elesclomol ([64Cu][Cu(ES)]) as a novel theranostic agent for hypoxic tumors, by implementing an improved production method and assessing its therapeutic and diagnostic potential compared to the established Cu-64 radiopharmaceuticals [64Cu]CuCl2 and [diacetyl-bis(N4-methylthiosemicarbazone) [64Cu][Cu(ATSM)].

METHODS

Cu-64 was produced using a biomedical cyclotron at 12 MeV with the reaction 64Ni(p,n)64Cu, followed by synthesis of [64Cu]CuCl2, [64Cu][Cu(ATSM)], and [64Cu][Cu(ES)]. In vitro therapeutic effects were assessed in both normoxic and hypoxic cells (22Rv1 and PC3 prostate cancer cells, and U-87MG glioblastoma cells) using the clonogenic assay and analyzing cellular uptake and internalization. In vivo therapeutic effects were assessed in 22Rv1 xenografts in BALB/cAnN-Foxn1nu/nu/Rj mice receiving a single or multiple doses of radiopharmaceutical, before their feasibility to detect tumor hypoxia was assessed by positron emission tomography (PET) in 22Rv1 and U-87MG xenografts.

RESULTS

In vitro and in vivo studies demonstrated that [64Cu][Cu(ES)] reduced cell survival and inhibited tumor growth more effectively than [64Cu][Cu(ATSM)] and [64Cu]CuCl2. Hypoxia increased the cellular uptake and internalization of [64Cu][Cu(ES)] and [64Cu][Cu(ATSM)]. [64Cu][Cu(ES)]-PET tumor hypoxia detection was feasible and also revealed an unexpected finding of uptake in the brain.

CONCLUSION

To the best of our knowledge, this is the first time that ES is radiolabeled with [64Cu]CuCl2 to [64Cu][Cu(ES)]. We demonstrated superior therapeutic effects of [64Cu][Cu(ES)] compared to [64Cu][Cu(ATSM)] and [64Cu]CuCl2 and that [64Cu][Cu(ES)]-PET is feasible. [64Cu][Cu(ES)] is a promising theranostic agent for hypoxic solid tumors.

The potential immuno-stimulating effect of curcumin, piperine, and taurine combination in hepatocellular carcinoma; a pilot study

BACKGROUND

This is a phase II clinical trial to investigate the immunotherapeutic effect of Curcumin, Piperine, and Taurine (CPT) combination in hepatocellular carcinoma (HCC).

METHODS

Twenty-six HCC patients aged (50-80 years) were recruited for administration of a daily dose of 5 g of curcumin, 50 mg of piperine, and 500 mg of taurine divided into three doses for successive 3 months. The three components (CPT) were prepared in one capsule. Patients were assessed after each month (cycle) for the plasma levels of CD4, CD8, CD25, Interleukins-2 (IL-2), IL-6, IL-12, Interferon-gamma (IFN- γ), Lactate dehydrogenase (LDH), and Vascular endothelial growth factor (VEGF), FOXP3 mRNA, and miRNA 21.

RESULTS

There was a significant increase in the plasma levels of CD4 and CD8, while a significant decrease in the CD25 level after the second and third cycles compared to the baseline level [P < 0.001 for both]. Also, there was a significant increase in the plasma levels of IL-2, IL-12, and IFN-γ [ P = 0.001, P = 0.006, and P = 0.029; respectively], while there was a significant decrease in IL-6, VEGF-α, LDH, and Alpha-fetoprotein (AFP) after CPT administration compared to the baseline levels [P < 0.001, P < 0.001, P = 0.020, and P = 0.004; respectively]. The expression level of miRNA-21 was significantly decreased after CPT administration compared to the baseline level [5.5±0.88, 4.1±0.78, 3±0.75, and 2.5±0.76; respectively, P<0.001]. Though there was a noticeable decrease in the FOXP3 expression after each cycle, however, it didn't reach a significant level [5.3±0.8, 4.2±0.76, 3.2±0.67, and 2.5±0.79; respectively, P=0.184].

CONCLUSION

CPT could exhibit a potential immune-stimulating effect in HCC patients. The current trial had been registered at the National Hepatology and Tropical Medicine Research Institute (NHTMRI), with a registration number of NHTMRI-IRB 2-21 on 5th January 2021.

Epigenetic signature of human immune aging in the GESTALT study

Age-associated DNA methylation in blood cells convey information on health status. However, the mechanisms that drive these changes in circulating cells and their relationships to gene regulation are unknown. We identified age-associated DNA methylation sites in six purified blood-borne immune cell types (naive B, naive CD4+ and CD8+ T cells, granulocytes, monocytes, and NK cells) collected from healthy individuals interspersed over a wide age range. Of the thousands of age-associated sites, only 350 sites were differentially methylated in the same direction in all cell types and validated in an independent longitudinal cohort. Genes close to age-associated hypomethylated sites were enriched for collagen biosynthesis and complement cascade pathways, while genes close to hypermethylated sites mapped to neuronal pathways. In silico analyses showed that in most cell types, the age-associated hypo- and hypermethylated sites were enriched for ARNT (HIF1β) and REST transcription factor (TF) motifs, respectively, which are both master regulators of hypoxia response. To conclude, despite spatial heterogeneity, there is a commonality in the putative regulatory role with respect to TF motifs and histone modifications at and around these sites. These features suggest that DNA methylation changes in healthy aging may be adaptive responses to fluctuations of oxygen availability.

Sestrin-2 and hypoxia-ınducible factor-1 alpha levels in major depressive disorder and its subtypes

BACKGROUND

The objective of this study is to measure the levels of sestrin-2 (SESN2) and hypoxia-inducible factor-1 alpha (HIF-1α), which can be determinants in the relevant physiopathology and etiology, assessment of the clinical severity, and identification of new treatment targets in major depressive disorder (MDD) and its subtypes.

METHODS

A total of 230 volunteers, including 153 patients diagnosed with MDD according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and 77 healthy controls, were included in the study. Of the MDD patients included in the study, 40 had melancholic features, 40 had anxious distress features, 38 had atypical features, and the remaining 35 had psychotic features. All participants were administered the Beck's Depression Inventory (BDI) and Clinical Global Impressions-Severity (CGI-S) scale. Serum SESN2 and HIF-1α levels of the participants were measured using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The HIF-1α and SESN2 values of the patient group were found to be significantly lower than those of the control group (p < 0.05). The HIF-1α and SESN2 values were significantly lower in patients with melancholic, anxious distress, and atypical features compared to the control group (p < 0.05). The HIF-1α and SESN2 levels did not differ significantly between patients with psychotic features and the control group (p > 0.05).

CONCLUSION

The findings of the study suggested that knowledge of SESN2 and HIF-1α levels may contribute to the explanation of the etiology of MDD, objective assessment of the severity of the disease, and identification of new treatment targets.

Genome editing and cancer therapy: handling the hypoxia-responsive pathway as a promising strategy

The precise characterization of oxygen-sensing pathways and the identification of pO2-regulated gene expression are both issues of critical importance. The O2-sensing system plays crucial roles in almost all the pivotal human processes, including the stem cell specification, the growth and development of tissues (such as embryogenesis), the modulation of intermediate metabolism (including the shift of the glucose metabolism from oxidative to anaerobic ATP production and vice versa), and the control of blood pressure. The solid cancer microenvironment is characterized by low oxygen levels and by the consequent activation of the hypoxia response that, in turn, allows a complex adaptive response characterized mainly by neoangiogenesis and metabolic reprogramming. Recently, incredible advances in molecular genetic methodologies allowed the genome editing with high efficiency and, above all, the precise identification of target cells/tissues. These new possibilities and the knowledge of the mechanisms of adaptation to hypoxia suggest the effective development of new therapeutic approaches based on the manipulation, targeting, and exploitation of the oxygen-sensor system molecular mechanisms.

A Receptor Story: Insulin Resistance Pathophysiology and Physiologic Insulin Resensitization's Role as a Treatment Modality

Physiologic insulin secretion consists of an oscillating pattern of secretion followed by distinct trough periods that stimulate ligand and receptor activation. Apart from the large postprandial bolus release of insulin, β cells also secrete small amounts of insulin every 4-8 min independent of a meal. Insulin resistance is associated with a disruption in the normal cyclical pattern of insulin secretion. In the case of type-2 diabetes, β-cell mass is reduced due to apoptosis and β cells secrete insulin asynchronously. When ligand/receptors are constantly exposed to insulin, a negative feedback loop down regulates insulin receptor availability to insulin, creating a relative hyperinsulinemia. The relative excess of insulin leads to insulin resistance (IR) due to decreased receptor availability. Over time, progressive insulin resistance compromises carbohydrate metabolism, and may progress to type-2 diabetes (T2D). In this review, we discuss insulin resistance pathophysiology and the use of dynamic exogenous insulin administration in a manner consistent with more normal insulin secretion periodicity to reverse insulin resistance. Administration of insulin in such a physiologic manner appears to improve insulin sensitivity, lower HgbA1c, and, in some instances, has been associated with the reversal of end-organ damage that leads to complications of diabetes. This review outlines the rationale for how the physiologic secretion of insulin orchestrates glucose metabolism, and how mimicking this secretion profile may serve to improve glycemic control, reduce cellular inflammation, and potentially improve outcomes in patients with diabetes.

HIF1α-dependent hypoxia response in myeloid cells requires IRE1α

Cellular adaptation to low oxygen tension triggers primitive pathways that ensure proper cell function. Conditions of hypoxia and low glucose are characteristic of injured tissues and hence successive waves of inflammatory cells must be suited to function under low oxygen tension and metabolic stress. While Hypoxia-Inducible Factor (HIF)-1α has been shown to be essential for the inflammatory response of myeloid cells by regulating the metabolic switch to glycolysis, less is known about how HIF1α is triggered in inflammation. Here, we demonstrate that cells of the innate immune system require activity of the inositol-requiring enzyme 1α (IRE1α/XBP1) axis in order to initiate HIF1α-dependent production of cytokines such as IL1β, IL6 and VEGF-A. Knockout of either HIF1α or IRE1α in myeloid cells ameliorates vascular phenotypes in a model of retinal pathological angiogenesis driven by sterile inflammation. Thus, pathways associated with ER stress, in partnership with HIF1α, may co-regulate immune adaptation to low oxygen.

Prognostic Value of HIF-1α-Induced Genes in Sepsis/Septic Shock

Hypoxia is characterized as one of the main consequences of sepsis, which is recognized as the leading cause of death in intensive care unit (ICU) patients. In this study, we aimed to examine whether the expression levels of genes regulated under hypoxia could be utilized as novel biomarkers for sepsis prognosis in ICU patients. Whole blood expression levels of hypoxia-inducible factor-1α (HIF1A), interferon-stimulated gene 15 (ISG15), hexokinase 2 (HK2), lactate dehydrogenase (LDHA), heme oxygenase-1 (HMOX1), erythropoietin (EPO), and the vascular endothelial growth factor A (VEGFA) were measured on ICU admission in 46 critically ill, initially non-septic patients. The patients were subsequently divided into two groups, based on the development of sepsis and septic shock (n = 25) or lack thereof (n = 21). HMOX1 mRNA expression was increased in patients who developed sepsis/septic shock compared to the non-septic group (p < 0.0001). The ROC curve, multivariate logistic regression, and Kaplan-Meier analysis demonstrated that HMOX1 expression could be utilized for sepsis and septic shock development probability. Overall, our results indicate that HMOX1 mRNA levels have the potential to be a valuable predictive factor for the prognosis of sepsis and septic shock in ICU patients.

Ginkgo Biloba and Long COVID: In Vivo and In Vitro Models for the Evaluation of Nanotherapeutic Efficacy

Coronavirus infections are neuroinvasive and can provoke injury to the central nervous system (CNS) and long-term illness consequences. They may be associated with inflammatory processes due to cellular oxidative stress and an imbalanced antioxidant system. The ability of phytochemicals with antioxidant and anti-inflammatory activities, such as Ginkgo biloba, to alleviate neurological complications and brain tissue damage has attracted strong ongoing interest in the neurotherapeutic management of long COVID. Ginkgo biloba leaf extract (EGb) contains several bioactive ingredients, e.g., bilobalide, quercetin, ginkgolides A-C, kaempferol, isorhamnetin, and luteolin. They have various pharmacological and medicinal effects, including memory and cognitive improvement. Ginkgo biloba, through its anti-apoptotic, antioxidant, and anti-inflammatory activities, impacts cognitive function and other illness conditions like those in long COVID. While preclinical research on the antioxidant therapies for neuroprotection has shown promising results, clinical translation remains slow due to several challenges (e.g., low drug bioavailability, limited half-life, instability, restricted delivery to target tissues, and poor antioxidant capacity). This review emphasizes the advantages of nanotherapies using nanoparticle drug delivery approaches to overcome these challenges. Various experimental techniques shed light on the molecular mechanisms underlying the oxidative stress response in the nervous system and help comprehend the pathophysiology of the neurological sequelae of SARS-CoV-2 infection. To develop novel therapeutic agents and drug delivery systems, several methods for mimicking oxidative stress conditions have been used (e.g., lipid peroxidation products, mitochondrial respiratory chain inhibitors, and models of ischemic brain damage). We hypothesize the beneficial effects of EGb in the neurotherapeutic management of long-term COVID-19 symptoms, evaluated using either in vitro cellular or in vivo animal models of oxidative stress.

The accumulated oxygen deficit as an indicator of the ischemic retinal insult

We here attempt to improve quantification of the ischemic retinal insult, that is, what is imposed on the retinal tissue by ischemia, especially in experimental models of ischemia. The ischemic retinal insult initiates the ischemic retinal injury (or outcome). Accordingly, it is reasonable to assume that the better the quantification of the insult, the better the correlation with, and thereby estimation of, the injury. The insult seldom has been quantified in terms of the relevant physiological factors, especially in connection with the rate of oxygen delivery (DO2). We here propose the accumulated oxygen deficit (AO2D) as an indicator of the ischemic retinal insult. We hypothesized that AO2D is correlated with the rate of oxygen metabolism measured 1 h after reperfusion following an episode of ischemia (MO2_1_Hr). Previously, we showed that MO2_1_Hr is related to the electroretinogram amplitude and the retinal thickness when they are measured seven days after reperfusion. We studied 27 rats, as well as 26 rats from our published data on retinal ischemia in which we had measurements of DO2 and duration of ischemia (T) of various levels and durations. We also measured DO2 in 29 rats treated with sham surgery. Ischemia was induced by either ipsilateral or bilateral common carotid artery occlusion or by ophthalmic artery occlusion, which gave a wide range of DO2. DO2 and MO2_1_Hr were evaluated based on three types of images: 1) red-free images to measure vessel diameters, 2) fluorescence images to estimate blood velocities by the displacement of intravascular fluorescent microspheres over time, and 3) phosphorescence images to quantify vascular oxygen tension from the phosphorescence lifetime of an intravascular oxygen sensitive phosphor. Loss of oxygen delivery (DO2L) was calculated as the difference between DO2 under normal/sham condition and DO2 during ischemia. AO2D, a volume of oxygen, was calculated as the product DO2L and T. Including all data, the linear relationship between AO2D and MO2_1_Hr was significant (R2 = 0.261, P = 0.0003). Limiting data to that in which T or DO2L was maximal also yielded significant relationships, and revealed that DO2L at a long duration of ischemia contributed disproportionately more than T to MO2_1_Hr. We discuss the potential of AO2D for quantifying the ischemic retinal insult, predicting the ischemic retinal injury and evaluating the likelihood of infarction.

Cyclic processes in the uterine tubes, endometrium, myometrium, and cervix: pathways and perturbations

This review leads the 2023 Call for Papers in MHR: 'Cyclical function of the female reproductive tract' and will outline the complex and fascinating changes that take place in the reproductive tract during the menstrual cycle. We will also explore associated reproductive tract abnormalities that impact or are impacted by the menstrual cycle. Between menarche and menopause, women and people who menstruate living in high-income countries can expect to experience ∼450 menstrual cycles. The primary function of the menstrual cycle is to prepare the reproductive system for pregnancy in the event of fertilization. In the absence of pregnancy, ovarian hormone levels fall, triggering the end of the menstrual cycle and onset of menstruation. We have chosen to exclude the ovaries and focus on the other structures that make up the reproductive tract: uterine tubes, endometrium, myometrium, and cervix, which also functionally change in response to fluctuations in ovarian hormone production across the menstrual cycle. This inaugural paper for the 2023 MHR special collection will discuss our current understanding of the normal physiological processes involved in uterine cyclicity (limited specifically to the uterine tubes, endometrium, myometrium, and cervix) in humans, and other mammals where relevant. We will emphasize where knowledge gaps exist and highlight the impact that reproductive tract and uterine cycle perturbations have on health and fertility.

Transcutaneous Electrical Nerve Stimulation (TENS) Alleviates Brain Ischemic Injury by Regulating Neuronal Oxidative Stress, Pyroptosis, and Mitophagy

Background

As a noninvasive treatment, transcutaneous electrical nerve stimulation (TENS) has been utilized to treat various diseases in clinic. However, whether TENS can be an effective intervention in the acute stage of ischemic stroke still remains unclear. In the present study, we aimed to explore whether TENS could alleviate brain infarct volume, reduce oxidative stress and neuronal pyroptosis, and activate mitophagy following ischemic stroke.

Methods

TENS was performed at 24 h after middle cerebral artery occlusion/reperfusion (MCAO/R) in rats for 3 consecutive days. Neurological scores, the volume of infarction, and the activity of SOD, MDA, GSH, and GSH-px were measured. Moreover, western blot was performed to detect the related protein expression, including Bcl-2, Bax, TXNIP, GSDMD, caspase-1, NLRP3, BRCC3, HIF-1α, BNIP3, LC3, and P62. Real-time PCR was performed to detect NLRP3 expression. Immunofluorescence was performed to detect the levels of LC3.

Results

There was no significant difference of neurological deficit scores between the MCAO group and the TENS group at 2 h after MCAO/R operation (P > 0.05), while the neurological deficit scores of TENS group significantly decreased in comparison with MCAO group at 72 h following MACO/R injury (P < 0.05). Similarly, TENS treatment significantly reduced the brain infarct volume compared with the MCAO group (P < 0.05). Moreover, TENS decreased the expression of Bax, TXNIP, GSDMD, caspase-1, BRCC3, NLRP3, and P62 and the activity of MDA as well as increasing the level of Bcl-2, HIF-1α, BNIP3, and LC3 and the activity of SOD, GSH, and GSH-px (P < 0.05).

Conclusions

In conclusion, our results indicated that TENS alleviated brain damage following ischemic stroke via inhibiting neuronal oxidative stress and pyroptosis and activating mitophagy, possibly via the regulation of TXNIP, BRCC3/NLRP3, and HIF-1α/BNIP3 pathways.

Glioblastoma Microenvironment and Invasiveness: New Insights and Therapeutic Targets

Glioblastoma (GBM) is the most common and malignant primary brain cancer in adults. Without treatment the mean patient survival is approximately 6 months, which can be extended to 15 months with the use of multimodal therapies. The low effectiveness of GBM therapies is mainly due to the tumor infiltration into the healthy brain tissue, which depends on GBM cells' interaction with the tumor microenvironment (TME). The interaction of GBM cells with the TME involves cellular components such as stem-like cells, glia, endothelial cells, and non-cellular components such as the extracellular matrix, enhanced hypoxia, and soluble factors such as adenosine, which promote GBM's invasiveness. However, here we highlight the role of 3D patient-derived glioblastoma organoids cultures as a new platform for study of the modeling of TME and invasiveness. In this review, the mechanisms involved in GBM-microenvironment interaction are described and discussed, proposing potential prognosis biomarkers and new therapeutic targets.

Unraveling the Underlying Molecular Mechanism of 'Silent Hypoxia' in COVID-19 Patients Suggests a Central Role for Angiotensin II Modulation of the AT1R-Hypoxia-Inducible Factor Signaling Pathway

A few days after being infected with SARS-CoV-2, a fraction of people remain asymptomatic but suffer from a decrease in arterial oxygen saturation in the absence of apparent dyspnea. In light of our clinical investigation on the modulation of molecules belonging to the renin angiotensin system (RAS) in COVID-19 patients, we propose a model that explains 'silent hypoxia'. The RAS imbalance caused by SARS-CoV-2 results in an accumulation of angiotensin 2 (Ang II), which activates the angiotensin 2 type 1 receptor (AT1R) and triggers a harmful cascade of intracellular signals leading to the nuclear translocation of the hypoxia-inducible factor (HIF)-1α. HIF-1α transactivates many genes including the angiotensin-converting enzyme 1 (ACE1), while at the same time, ACE2 is downregulated. A growing number of cells is maintained in a hypoxic condition that is self-sustained by the presence of the virus and the ACE1/ACE2 ratio imbalance. This is associated with a progressive worsening of the patient's biological parameters including decreased oxygen saturation, without further clinical manifestations. When too many cells activate the Ang II-AT1R-HIF-1α axis, there is a 'hypoxic spillover', which marks the tipping point between 'silent' and symptomatic hypoxia in the patient. Immediate ventilation is required to prevent the 'hypoxic spillover'.

Effects of Pawpaw (Asimina triloba) Seed Extract on the Differentiation and Fat Accumulation of 3T3-L1 Cells under Different Glucose Conditions

Asimina triloba (pawpaw) contains various bioactive alkaloids and acetogenins. In the present study, the effects of pawpaw seed extract (PSE) on adipocyte differentiation and fat accumulation were investigated in 3T3-L1 cells under different glucose conditions. Treatment of undifferentiated cells with 10 ng/mL PSE increased lactic acid production, suggesting enhanced anaerobic glycolysis. PSE treatment also suppressed cell proliferation and decreased the nicotinamide adenine dinucleotide (NAD)⁺/NADH ratio in low-glucose medium; however, this effect was not observed in high-glucose medium. Additionally, PSE treatment under low-glucose conditions resulted in reduced accumulation of triglycerides and decreased expression of peroxisome proliferator-activated receptor (PPAR)-γ, CAAT/enhancer-binding protein (C/EBP)-α, and sterol regulatory element binding protein (SREBP)-1c in adipocyte-differentiated cells. PSE exerted greater effects on adipocyte differentiation and triglyceride content in 3T3-L1 cells under low-glucose conditions than under high-glucose conditions. These findings indicate that PSE enhances anaerobic glycolysis and inhibits adipocyte differentiation and fat accumulation in 3T3-L1 cells under glucose-restricted conditions.

Sestrin2 as a Protective Shield against Cardiovascular Disease

A timely and adequate response to stress is inherently present in each cell and is important for maintaining the proper functioning of the cell in changing intracellular and extracellular environments. Disruptions in the functioning or coordination of defense mechanisms against cellular stress can reduce the tolerance of cells to stress and lead to the development of various pathologies. Aging also reduces the effectiveness of these defense mechanisms and results in the accumulation of cellular lesions leading to senescence or death of the cells. Endothelial cells and cardiomyocytes are particularly exposed to changing environments. Pathologies related to metabolism and dynamics of caloric intake, hemodynamics, and oxygenation, such as diabetes, hypertension, and atherosclerosis, can overwhelm endothelial cells and cardiomyocytes with cellular stress to produce cardiovascular disease. The ability to cope with stress depends on the expression of endogenous stress-inducible molecules. Sestrin2 (SESN2) is an evolutionary conserved stress-inducible cytoprotective protein whose expression is increased in response to and defend against different types of cellular stress. SESN2 fights back the stress by increasing the supply of antioxidants, temporarily holding the stressful anabolic reactions, and increasing autophagy while maintaining the growth factor and insulin signaling. If the stress and the damage are beyond repair, SESN2 can serve as a safety valve to signal apoptosis. The expression of SESN2 decreases with age and its levels are associated with cardiovascular disease and many age-related pathologies. Maintaining sufficient levels or activity of SESN2 can in principle prevent the cardiovascular system from aging and disease.

The pyruvate dehydrogenase complex: Life's essential, vulnerable and druggable energy homeostat

Found in all organisms, pyruvate dehydrogenase complexes (PDC) are the keystones of prokaryotic and eukaryotic energy metabolism. In eukaryotic organisms these multi-component megacomplexes provide a crucial mechanistic link between cytoplasmic glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle. As a consequence, PDCs also influence the metabolism of branched chain amino acids, lipids and, ultimately, oxidative phosphorylation (OXPHOS). PDC activity is an essential determinant of the metabolic and bioenergetic flexibility of metazoan organisms in adapting to changes in development, nutrient availability and various stresses that challenge maintenance of homeostasis. This canonical role of the PDC has been extensively probed over the past decades by multidisciplinary investigations into its causal association with diverse physiological and pathological conditions, the latter making the PDC an increasingly viable therapeutic target. Here we review the biology of the remarkable PDC and its emerging importance in the pathobiology and treatment of diverse congenital and acquired disorders of metabolic integration.

Lower starting dose of roxadustat in non-dialysis-dependent chronic kidney disease patients with anaemia: a study protocol for a randomised, multicentre, open-label study

INTRODUCTION

Roxadustat is a first-in-class oral therapy that treats chronic kidney disease (CKD) anaemia with the benefit of a novel mechanism of action that consistently corrects and maintains haemoglobin (Hb) across the spectrum of non-dialysis-dependent (NDD) CKD anaemia with an acceptable safety profile.

METHODS AND ANALYSIS

This is a randomised, control, open-label, multicentre trial. About 250 adult Chinese participants with stage 3-5 CKD NDD in approximately 30 centres will be enrolled, randomly assigned in a 1:1 ratio, to receive a 16-week treatment and 4-week follow-up. The interventions for study arm are <60 kg: 50 mg TIW and ≥60 kg: 70 mg TIW; for control arm, <60 kg: 70 mg TIW and ≥60 kg: 100 mg TIW. The primary endpoint is the mean change in haemoglobin level from baseline to average over weeks 12-16. Secondary endpoints are to assess the proportion of subjects achieving an average Hb level of 100 to 120 g/L over weeks 12-16, the Hb variability, the rescue therapy requirement between two groups and the safety in two groups. The exploratory objectives are expected to evaluate the rate and time of Hb response, times of dose adjustment, the proportion of subjects with rapid Hb rise, overshooting during the treatment between two different starting dose groups, and subgroup analyses.

ETHICS AND DISSEMINATION

The Medical Ethics Committee of Chinese PLA General Hospital has approved this study (No. S2020-523-05) and will be performed in accordance with the Declaration of Helsinki. Participant consent will be obtained in writing. Results will be disseminated via peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR2100045359.

Recent progress of biocompatible carbon dots in hypoxia-related fields

Almost all eukaryotes need oxygen to maintain regular physiological activities. When the organism is under hypoxic situation for a persistent or periodic, it will induce irreversible physiological disorders and even pathological results. Hypoxia is closely related to the pathogenesis of metabolic diseases, cancer, chronic heart disease and kidney disease, myocardial ischemia, as well as reproductive diseases like preeclampsia and endometriosis. Therefore, monitoring and treatment of hypoxia have important implications for the pathophysiology of human-related diseases. Carbon dots (CDs) are emerging nanomaterials developed after 2004 with excellent performance, and have broad application potential in variousdomains likeoptical, biomedicine, energy. Advanced hypoxia therapeutics should be integrated with monitoring and treatment, and CDs with excellent performance are good potential options when sensing is combined with various therapeutic methods. Some researchers have also begun to carry out research in related fields and achieved some results. This article aims to clarify the various applications of CDs in hypoxia-related fields in recent years, including hypoxia sensing and hypoxia tumor theranostics. Finally, the possible challenges and prospects for the application of CDs in hypoxia-related fields are discussed.

Indole-3-carbinol ameliorated the neurodevelopmental deficits in neonatal anoxic injury in rats

Neonatal anoxia is linked to long-lasting neurodevelopmental deficits. Due to the lack of pharmacological intervention to treat neonatal anoxia, there is interest in finding new molecules for its treatment. Indole-3-carbinol (I3C) has shown neuroprotective effects in some disease conditions. However, the neuroprotective role of I3C in neonatal anoxia has not been explored. Consequently, we have investigated the effect of I3C on neonatal anoxia-induced brain injury and neurodevelopmental deficits. Rat pups after 30 h of birth were subjected to two episodes of anoxia (10 min in each) at a time interval of 24 h by flowing 100% nitrogen. I3C was administered within 30 min of the second episode of anoxia on a postnatal day (PND) 3 and continued for PND 9. Neurodevelopmental deficits, cortical mitochondrial membrane potential (MMP), opening of mitochondrial permeability transition pore (MPTP), electron transport chain (ETC) enzyme activities, oxidative stress, hypoxia-inducible factor-1α (HIF-1α) levels, histopathological changes, and apoptosis were measured. I3C treatment dose-dependently ameliorated the neurodevelopmental deficits and somatic growth in anoxic pups. I3C improved mitochondrial function by enhancing the MMP, mitochondrial ETC enzymes, and antioxidants. It blocked the MPTP opening and release of cytochrome C in anoxic pups. Further, I3C reduced the elevated cortical HIF-1α in neonatal anoxic pups. Furthermore, I3C ameliorated histopathological abnormalities and mitochondrial-mediated apoptotic indicators Cyt C, caspase-9, and caspase-3. Our study concludes that I3C improved neuronal development in anoxic pups by enhancing mitochondrial function, reducing HIF-1α, and mitigating apoptosis.

Biomaterials delivery strategies to repair degenerated intervertebral discs by regulating the inflammatory microenvironment

Intervertebral disc degeneration (IVDD) is one of the leading causes of lower back pain. Although IVDD cannot directly cause death, it can cause pain, psychological burdens, and economic burdens to patients. Current conservative treatments for IVDD can relieve pain but cannot reverse the disease. Patients who cannot tolerate pain usually resort to a strategy of surgical resection of the degenerated disc. However, the surgical removal of IVDD can affect the stability of adjacent discs. Furthermore, the probability of the reherniation of the intervertebral disc (IVD) after surgery is as high as 21.2%. Strategies based on tissue engineering to deliver stem cells for the regeneration of nucleus purposes (NP) and annulus fibrosus (AF) have been extensively studied. The developed biomaterials not only locally withstand the pressure of the IVD but also lay the foundation for the survival of stem cells. However, the structure of IVDs does not provide sufficient nutrients for delivered stem cells. The role of immune mechanisms in IVDD has recently become clear. In IVDD, the IVD that was originally in immune privilege prevents the attack of immune cells (mainly effector T cells and macrophages) and aggravates the disease. Immune regulatory and inflammatory factors released by effector T cells, macrophages, and the IVD further aggravate IVDD. Reversing IVDD by regulating the inflammatory microenvironment is a potential approach for the treatment of the disease. However, the biological factors modulating the inflammatory microenvironment easily degrade in vivo. It makes it possible for different biomaterials to modulate the inflammatory microenvironment to repair IVDD. In this review, we have discussed the structures of IVDs and the immune mechanisms underlying IVDD. We have described the immune mechanisms elicited by different biological factors, including tumor necrosis factors, interleukins, transforming growth factors, hypoxia-inducible factors, and reactive oxygen species in IVDs. Finally, we have discussed the biomaterials used to modulate the inflammatory microenvironment to repair IVDD and their development.

Hypoxia-Driven Changes in a Human Intestinal Organoid Model and the Protective Effects of Hydrolyzed Whey

Many whey proteins, peptides and protein-derived amino acids have been suggested to improve gut health through their anti-oxidant, anti-microbial, barrier-protective and immune-modulating effects. Interestingly, although the degree of hydrolysis influences peptide composition and, thereby, biological function, this important aspect is often overlooked. In the current study, we aimed to investigate the effects of whey protein fractions with different degrees of enzymatic hydrolysis on the intestinal epithelium in health and disease with a novel 2D human intestinal organoid (HIO) monolayer model. In addition, we aimed to assess the anti-microbial activity and immune effects of the whey protein fractions. Human intestinal organoids were cultured from adult small intestines, and a model enabling apical administration of nutritional components during hypoxia-induced intestinal inflammation and normoxia (control) in crypt-like and villus-like HIO was established. Subsequently, the potential beneficial effects of whey protein isolate (WPI) and two whey protein hydrolysates with a 27.7% degree of hydrolysis (DH28) and a 50.9% degree of hydrolysis (DH51) were assessed. In addition, possible immune modulatory effects on human peripheral immune cells and anti-microbial activity on four microbial strains of the whey protein fractions were investigated. Exposure to DH28 prevented paracellular barrier loss of crypt-like HIO following hypoxia-induced intestinal inflammation with a concomitant decrease in hypoxia inducible factor 1 alpha (HIF1α) mRNA expression. WPI increased Treg numbers and Treg expression of cluster of differentiation 25 (CD25) and CD69 and reduced CD4+ T cell proliferation, whereas no anti-microbial effects were observed. The observed biological effects were differentially mediated by diverse whey protein fractions, indicating that (degree of) hydrolysis influences their biological effects. Moreover, these new insights may provide opportunities to improve immune tolerance and promote intestinal health.

Facts and Perspectives: Implications of tumor glycolysis on immunotherapy response in triple negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive disease that is difficult to treat and portends a poor prognosis in many patients. Recent efforts to implement immune checkpoint inhibitors into the treatment landscape of TNBC have led to improved outcomes in a subset of patients both in the early stage and metastatic settings. However, a large portion of patients with TNBC remain resistant to immune checkpoint inhibitors and have limited treatment options beyond cytotoxic chemotherapy. The interplay between the anti-tumor immune response and tumor metabolism contributes to immunotherapy response in the preclinical setting, and likely in the clinical setting as well. Specifically, tumor glycolysis and lactate production influence the tumor immune microenvironment through creation of metabolic competition with infiltrating immune cells, which impacts response to immune checkpoint blockade. In this review, we will focus on how glucose metabolism within TNBC tumors influences the response to immune checkpoint blockade and potential ways of harnessing this information to improve clinical outcomes.

The immunolocalization of HIF-2α, GLUT1 and CAIX in porcine oviduct during the estrous cycle

Oxygen (O₂ ) rates in the oviduct are essential to human and animal reproduction. These rates are regulated by the activity of hypoxia markers such as the hypoxia-inducible factors (HIFs), the glucose transporters (GLUT), and the carbonic anhydrase (CA). In the porcine model, scarce studies have been reported regarding these markers and their effects in reproduction are unknown. The objective was to characterize the immunolocalization of HIF-2α, GLUT1, and CAIX in porcine oviducts throughout the estrous cycle. Oviducts (ampulla and isthmus) of adult sows (n = 45) were collected for histological and immunohistochemical analysis with HIF-2α, GLUT1, and CAIX markers. The percentage of immunopositive area was quantified, and the differences among phases of the estrous cycle were analyzed (folicular, early luteal, and late luteal). The three markers showed epithelial presence mainly. Significantly lower expression of HIF-2α was found in the luteal phases, especially in the isthmus. GLUT1 expression did not change throughout the estrous cycle, but differences were found between the ampulla and isthmus. CAIX expression showed the highest, with a significant downward trend throughout estrous cycle. The ubiquitous expression of hypoxia markers shows the porcine oviduct physiology in relation to O₂ . The differential expression of HIF-2α, GLUT1, and CAIX in different subcompartments of the oviduct throughout the estrous cycle contributes to improve the knowledge of the cell physiology of the oviduct, which can be useful in fertilization studies.

Extracellular vesicles released during hypoxia transport heparanase and enhance macrophage migration, endothelial tube formation and cancer cell stemness

Heparanase is upregulated during the progression of most cancers and via its enzyme activity promotes extracellular matrix degradation, angiogenesis and cell migration. Heparanase expression is often associated with enhanced tumor aggressiveness and chemoresistance. We previously demonstrated that increased heparanase expression in tumor cells enhances secretion and alters the composition of tumor-released exosomes. In the present study, we discovered that extracellular vesicles (EVs) secreted by human multiple myeloma cells growing in hypoxic conditions exhibited elevated levels of heparanase cargo compared to EVs from cells growing in normoxic conditions. When macrophages (RAW 264.7 monocyte/macrophage-like cells) were exposed to EVs released by tumor cells growing in either hypoxic or normoxic conditions, macrophage migration and invasion was elevated by EVs from hypoxic conditions. The elevated invasion of macrophages was blocked by a monoclonal antibody that inhibits heparanase enzyme activity. Moreover, the heparanase-bearing EVs from hypoxic cells greatly enhanced endothelial cell tube formation consistent with the known role of heparanase in promoting angiogenesis. EVs from hypoxic tumor cells when compared with EVs from normoxic cells also enhanced cancer stemness properties of both CAG and RPMI 8226 human myeloma cells. Together these data indicate that under hypoxic conditions, tumor cells secrete EVs having an elevated level of heparanase as cargo. These EVs can act on both tumor and non-tumor cells, enhancing tumor progression and tumor cell stemness that likely supports chemoresistance and relapse of tumor.

Bioactive PI3-kinase/Akt/mTOR Inhibitors in Targeted Lung Cancer Therapy

One of the central signaling pathways with a regulatory effect on cell proliferation and survival is Akt/mTOR. In many human cancer types, for instance, lung cancer, the overexpression of Akt/mTOR has been reported. For this reason, either targeting cancer cells by synthetic or natural products affecting the Akt/mTOR pathway down-regulation is a useful strategy in cancer therapy. Direct inhibition of the signaling pathway or modulation of each related molecule could have significant feedback on the growth and proliferation of cancer cells. A variety of secondary metabolites has been identified to directly inhibit the AKT/mTOR signaling, which is important in the field of drug discovery. Naturally occurring nitrogenous and phenolic compounds can emerge as two pivotal classes of natural products possessing anticancer abilities. Herein, we have summarized the alkaloids and flavonoids for lung cancer treatment together with all the possible mechanisms of action relying on the Akt/mTOR pathway down-regulation. This review suggested that in search of new drugs, phytochemicals could be considered as promising scaffolds to be developed into efficient drugs for the treatment of cancer. In this review, the terms "Akt/mTOR", "Alkaloid", "flavonoid", and "lung cancer" were searched without any limitation in search criteria in Scopus, PubMed, Web of Science, and Google scholar engines.

Oxidative Stress Response's Kinetics after 60 Minutes at Different (30% or 100%) Normobaric Hyperoxia Exposures

Oxygen is a powerful trigger for cellular reactions and is used in many pathologies, including oxidative stress. However, the effects of oxygen over time and at different partial pressures remain poorly understood. In this study, the metabolic responses of normobaric oxygen intake for 1 h to mild (30%) and high (100%) inspired fractions were investigated. Fourteen healthy non-smoking subjects (7 males and 7 females; age: 29.9 ± 11.1 years, height: 168.2 ± 9.37 cm; weight: 64.4 ± 12.3 kg; BMI: 22.7 ± 4.1) were randomly assigned in the two groups. Blood samples were taken before the intake at 30 min, 2 h, 8 h, 24 h, and 48 h after the single oxygen exposure. The level of oxidation was evaluated by the rate of reactive oxygen species (ROS) and the levels of isoprostane. Antioxidant reactions were observed by total antioxidant capacity (TAC), superoxide dismutase (SOD), and catalase (CAT). The inflammatory response was measured using interleukin-6 (IL-6), neopterin, creatinine, and urates. Oxidation markers increased from 30 min on to reach a peak at 8 h. From 8 h post intake, the markers of inflammation took over, and more significantly with 100% than with 30%. This study suggests a biphasic response over time characterized by an initial "permissive oxidation" followed by increased inflammation. The antioxidant protection system seems not to be the leading actor in the first place. The kinetics of enzymatic reactions need to be better studied to establish therapeutic, training, or rehabilitation protocols aiming at a more targeted use of oxygen.

Hypoxia-induced factor and its role in liver fibrosis

Liver fibrosis develops as a result of severe liver damage and is considered a major clinical concern throughout the world. Many factors are crucial for liver fibrosis progression. While advancements have been made to understand this disease, no effective pharmacological drug and treatment strategies have been established that can effectively prevent liver fibrosis or even could halt the fibrotic process. Most of those advances in curing liver fibrosis have been aimed towards mitigating the causes of fibrosis, including the development of potent antivirals to inhibit the hepatitis virus. It is not practicable for many individuals; however, a liver transplant becomes the only suitable alternative. A liver transplant is an expensive procedure. Thus, there is a significant need to identify potential targets of liver fibrosis and the development of such agents that can effectively treat or reverse liver fibrosis by targeting them. Researchers have identified hypoxia-inducible factors (HIFs) in the last 16 years as important transcription factors driving several facets of liver fibrosis, making them possible therapeutic targets. The latest knowledge on HIFs and their possible role in liver fibrosis, along with the cell-specific activities of such transcription factors that how they play role in liver fibrosis progression, is discussed in this review.

Low-dose anti-VEGFR2 therapy promotes anti-tumor immunity in lung adenocarcinoma by down-regulating the expression of layilin on tumor-infiltrating CD8+T cells

PURPOSE

Our study intended to explore how low-dose anti-angiogenic drugs affected anti-tumor immunity of tumor-infiltrating exhausted CD8⁺T cells and achieved better clinical response when combined with immunotherapy. We set out to find potential targets or predictive biomarker on CD8⁺T cells for immunotherapy.

METHODS

We tested different doses of anti-VEGFR2 antibody combined with anti-PD1 antibody to treat LUAD in vivo and analyzed tumor-infiltrating CD8⁺T cells by flow cytometry. CD8⁺T cells overexpressing LAYN were co-cultured with LA795 cell lines to identify the function of LAYN in CD8⁺T cells. We also analyzed clinical samples from advanced LUAD patients treated with anti-angiogenesis therapy combined with immunotherapy.

RESULTS

Low-dose anti-VEGFR2 antibody combined with anti-PD1 antibody treatment delayed tumor growth and prolonged the survival time of tumor-bearing mice. The number of tumor-infiltrating CD8⁺T cells was reduced and the expression of LAYN was down-regulated in tumor-infiltrating CD8⁺T cells in the low-dose anti-VEGFR2 combination group. It was found that LAYN inhibited the killing function of CD8⁺T cells. In patients with advanced LUAD who received anti-angiogenesis therapy combined with immunotherapy, the LAYN⁺CD8⁺T cell subpopulation in good responders was significantly higher than that in poor responders. Furthermore, we demonstrated the expression of LAYN was regulated by upstream transcription factor NR4A1.

CONCLUSION

Low-dose anti-VEGFR2 antibody combined with anti-PD1 antibody therapy promoted anti-tumor immunity and the downregulation of LAYN in tumor-infiltrating CD8⁺T cells played an important role in this process. These findings had implications for improving the efficacy of immune checkpoint blockade therapy and further optimized clinical treatment guidelines in advanced LUAD.

The role of hypoxia and inflammation in the regulation of iron metabolism and erythropoiesis in COVID-19: The IRONCOVID study

Coronavirus Disease (COVID-19) can be considered as a human pathological model of inflammation combined with hypoxia. In this setting, both erythropoiesis and iron metabolism appear to be profoundly affected by inflammatory and hypoxic stimuli, which act in the opposite direction on hepcidin regulation. The impact of low blood oxygen levels on erythropoiesis and iron metabolism in the context of human hypoxic disease (e.g., pneumonia) has not been fully elucidated. This multicentric observational study was aimed at investigating the prevalence of anemia, the alterations of iron homeostasis, and the relationship between inflammation, hypoxia, and erythropoietic parameters in a cohort of 481 COVID-19 patients admitted both to medical wards and intensive care units (ICU). Data were collected on admission and after 7 days of hospitalization. On admission, nearly half of the patients were anemic, displaying mild-to-moderate anemia. We found that hepcidin levels were increased during the whole period of observation. The patients with a higher burden of disease (i.e., those who needed intensive care treatment or had a more severe degree of hypoxia) showed lower hepcidin levels, despite having a more marked inflammatory pattern. Erythropoietin (EPO) levels were also lower in the ICU group on admission. After 7 days, EPO levels rose in the ICU group while they remained stable in the non-ICU group, reflecting that the initial hypoxic stimulus was stronger in the first group. These findings strengthen the hypothesis that, at least in the early phases, hypoxia-driven stimuli prevail over inflammation in the regulation of hepcidin and, finally, of erythropoiesis.

Impact of the redox environment on propagation of radiation bystander effects: The modulating effect of oxidative metabolism and oxygen partial pressure

Redox modulated pathways play important roles in out-of-field effects of ionizing radiation. We investigated how the redox environment impacts the magnitude of propagation of stressful effects from irradiated to bystander cells. Normal human fibroblasts that have incorporated [³H]-thymidine were intimately co-cultured with bystander cells in a strategy that allowed isolation of bystander cells with high purity. The antioxidant glutathione peroxidase (GPX) was maintained either at wild-type conditions or overexpressed in the bystanders. Following 24 h of coculture, levels of stress-responsive p21^Waf1, p-Hdm2, and connexin43 proteins were increased in bystander cells expressing wild-type GPX relative to respective controls. These levels were significantly attenuated when GPX was ectopically overexpressed, demonstrating by direct approach the involvement of a regulator of intracellular redox homeostasis. Evidence of participation of pro-oxidant compounds was generated by exposing confluent cell cultures to low fluences of 3.7 MeV α particles in presence or absence of t-butyl hydroperoxide. By 3 h post-exposure to fluences wherein only ∼2% of cells are traversed through the nucleus by a particle track, increases in chromosomal damage were greater than expected in absence of the drug (p < 0.001) and further enhanced in its presence (p < 0.05). While maintenance and irradiation of cell cultures at low oxygen pressure (pO₂ 3.8 mm Hg) to mimic in vivo still supported the participation of bystander cells in responses assessed by chromosomal damage and stress-responsive protein levels (p < 0.001), the effects were attenuated compared to ambient pO₂ (155 mm Hg) (p < 0.05). Together, the results show that bystander effects are attenuated at below ambient pO₂ and when metabolic oxidative stress is reduced but increased when the basal redox environment tilts towards oxidizing conditions. They are consistent with bystander effects being independent of radiation dose rate.

Venous Wall of Patients with Chronic Venous Disease Exhibits a Glycolytic Phenotype

Chronic venous disease (CVeD) is a rising medical condition characterized by a broad spectrum of disorders in the venous system. Varicose veins (VVs) represent a frequent clinical manifestation of CVeD, particularly in the lower limbs. Prior histopathological studies have defined a set of alterations observed in the venous wall of patients with VVs, affecting their structure and behavior. Metabolic changes in the veins appear to be a critical biological mechanism aiding our understanding of the pathogenesis of CVeD. In this sense, previous studies have identified a potential role of a glycolytic phenotype in the development of different vascular disorders; however, its precise role in CVeD remains to be fully explored. Thus, the aim of the present study was to analyze the gene and protein expression of glucose transporter 1 (GLUT-1) and the glycolytic enzymes PGK-1, ALD, GA3PDH and LDH in the VVs of patients with CVeD (n = 35) in comparison to those expressed in healthy subjects. Our results display enhanced gene and protein expression of GLUT-1, PGK-1, ALD, GA3PDH and LDH in patients with CVeD, suggesting a glycolytic switch of the venous tissue. Greater understanding of the impact of this glycolytic switch in patients with CVeD is required to define a possible pathophysiological role or therapeutic implications of these changes.

miR‑519d‑3p released by human blastocysts negatively regulates endometrial epithelial cell adhesion by targeting HIF1α

Successful embryo implantation requires a competent embryo, a receptive endometrium and synchronized communication between them. The selection of embryos with the highest implantation potential remains a challenge in the field of assisted reproductive technology. Moreover, little is known about the precise molecular mechanisms underlying embryo‑endometrium crosstalk. MicroRNAs (miRNAs/miRs) have been detected in the spent embryo culture medium (SCM); however, their functions at the preimplantation stage remain unclear. In the present study, human SCM samples were collected during in vitro fertilization/intracytoplasmic sperm injection‑embryo transfer and divided into implanted and not‑implanted groups according to the clinical pregnancy outcomes. Total RNA was extracted and six miRNAs (miR‑372‑3p, miR‑373‑3p, miR‑516b‑5p, miR‑517a‑3p, miR‑519d‑3p and miR‑520a‑3p) were selected for reverse transcription‑quantitative PCR (RT‑qPCR) analysis. The results revealed that miR‑372‑3p and miR‑519d‑3p were markedly increased in SCM from blastocysts that failed to implant compared with in blastocysts that implanted. The receiver operating characteristic curve analysis revealed that miR‑519d‑3p was superior to miR‑372‑3p in predicting pregnancy outcomes. In vitro miRNA uptake and cell adhesion assays were performed to determine whether miR‑519d‑3p could be taken up by endometrial epithelial cells and to examine the biological roles of miR‑519d‑3p after internalization. Potential targets of miR‑519d‑3p were verified using a dual‑luciferase reporter system. The results demonstrated that miR‑519d‑3p was taken up by human endometrial epithelial cells and that it may inhibit embryo adhesion by targeting HIF1α. Using RT‑qPCR, western blot analysis and flow cytometry assay, HIF1α was shown to inhibit the biosynthesis of fucosyltransferase 7 and sialyl‑Lewis X (sLe^x), a cell‑surface oligosaccharide that serves an important role in embryonic apposition and adhesion. In addition, a mouse model was established and the results suggested that miR‑519d‑3p overexpression hampered embryo implantation in vivo. Taken together, miRNAs in SCM may serve as novel biomarkers for embryo quality. Furthermore, miR‑519d‑3p was shown to mediate embryo‑endometrium crosstalk and to negatively regulate embryo implantation by targeting HIF1α/FUT7/sLe^x pathway.

From menarche to menopause, heavy menstrual bleeding is the underrated compass in reproductive health

Menstruation is defined as monthly uterine bleeding, regarded as a sign of reproductive health. When characterized by excessive bleeding (heavy menstrual bleeding [HMB]), it may act as a useful clinical marker for diagnosis of reproductive diseases. Endometrial and myometrial mechanisms underlying abnormal uterine bleeding (AUB), which includes HMB, have hormonal, cellular, and molecular aspects. Structural and nonstructural causes of AUB, presenting with HMB as the major symptom, result in iron depletion and consequent anemia. Heavy menstrual bleeding can be considered as a single entity to identify the possible underlying causes, which may be different to some extent to those of AUB, as a whole. Furthermore, the difficulties in defining HMB through objective methods do not allow the current epidemiological scenario on the prevalence of the symptom among reproductive-age women to be outlined. Moreover, the introduction of new diagnostic methods, including imaging technologies, entails a revision of the available figures on HMB in different age groups from menarche to menopause. In addition, a proper diagnostic algorithm for HMB should be implemented to adapt recommendations for clinical investigation when HMB is present.

ERK/HIF-1α/VEGF pathway: a molecular target of ELABELA (ELA) peptide for attenuating cardiac ischemia-reperfusion injury in rats by promoting angiogenesis

BACKGROUND

Myocardial ischemia-reperfusion (I/R) injury is caused by a chain of events such as endothelial dysfunction. This study was conducted to investigate protective effects of ELABELA against myocardial I/R in Wistar rats and clarify its possible mechanisms. METHODS AND RESULTS: MI model was established based on the left anterior descending coronary artery ligation for 30 min. Then, 5 µg/kg of ELA peptide was intraperitoneally infused in rats once per day for 4 days. Western blot assay was used to assay the expression of t-ERK1/2, and p-ERK1/2 in different groups. The amount of myocardial capillary density, the expression levels of VEGF and HIF-1α were evaluated using immunohistochemistry assay. Masson's trichrome staining was utilized to assay cardiac interstitial fibrosis. The results showed that establishment of MI significantly enhanced cardiac interstitial fibrosis and changed p-ERK1/2/ t-ERK1/2 ratio. Likewise, ELA post-treatment markedly increased myocardial capillary density, the expression of several angiogenic factors (VEGF-A, HIF-1α), and reduced cardiac interstitial fibrosis by activation of ERK1/2 signaling pathways.

CONCLUSION

Collectively, ELA peptide has ability to reduce myocardial I/R injury by promoting angiogenesis and reducing cardiac interstitial fibrosis through activating ERK/HIF-1α/VEGF pathway.

Effect of the addition of 4OHE2 and quercetin in culture media on ROS levels and gene expression in mouse blastocysts

AIMS

The main objective of this work is to elucidate whether Quercetin (Qc) and 4-Hidroxistradiol (4OHE2 ) decrease the level of reactive oxygen species (ROS) in in vitro obtained embryos and to analyse which genes are activated under the treatments that could explain this improvement.

METHODS

Oxidative stress was induced during embryo culture by H2 O2 treatment and ROS production was measured and compared with embryos treated with Qc or 4OHE2 . Gene expression was analysed by Q-PCR in control embryos obtained in utero (IU) or by IVF and compared with the levels found in embryos cultured with Qc or 4OHE2 to determine the effect of these compounds.

KEY RESULTS

Qc strongly reduces ROS levels in embryos after a treatment of 4h. On the contrary, 4OHE2 had no effect in reducing ROS levels in embryos. The addition of these molecules to the culture media upregulate several hypoxia-related genes when Qc is added to the culture media, and implantation-related genes when 4OHE2 is used.

CONCLUSIONS

Qc is a very strong antioxidant molecule that when used for short periods of time during culture can reduce ROS levels and improve embryo quality by activating antioxidant enzymes. 4OHE2 supplementation, despite having no effects in reducing ROS levels, acts directly in the molecular signalling implicated in the implantation process and could be also considered as a supplement for embryo culture during IVF.

IMPLICATIONS

Proper supplementation of the culture media could greatly improve the quality of embryos cultured in vitro , resulting in better results in IVF clinics.

The impact of COVID-19 on populations living at high altitude: Role of hypoxia-inducible factors (HIFs) signaling pathway in SARS-CoV-2 infection and replication

Cases of coronavirus disease 2019 (COVID-19) have been reported worldwide. However, one epidemiological report has claimed a lower incidence of the disease in people living at high altitude (&gt;2,500 m), proposing the hypothesis that adaptation to hypoxia may prove to be advantageous with respect to SARS-CoV-2 infection. This publication was initially greeted with skepticism, because social, genetic, or environmental parametric variables could underlie a difference in susceptibility to the virus for people living in chronic hypobaric hypoxia atmospheres. Moreover, in some patients positive for SARS-CoV-2, early post-infection ‘happy hypoxia” requires immediate ventilation, since it is associated with poor clinical outcome. If, however, we accept to consider the hypothesis according to which the adaptation to hypoxia may prove to be advantageous with respect to SARS-CoV-2 infection, identification of the molecular rational behind it is needed. Among several possibilities, HIF-1 regulation appears to be a molecular hub from which different signaling pathways linking hypoxia and COVID-19 are controlled. Interestingly, HIF-1α was reported to inhibit the infection of lung cells by SARS-CoV-2 by reducing ACE2 viral receptor expression. Moreover, an association of the rs11549465 variant of HIF-1α with COVID-19 susceptibility was recently discovered. Here, we review the evidence for a link between HIF-1α, ACE2 and AT1R expression, and the incidence/severity of COVID-19. We highlight the central role played by the HIF-1α signaling pathway in the pathophysiology of COVID-19.