Hypoxia-Inducible Factor 1-α (HIF-1α) Induces Apoptosis of Human Uterosacral Ligament Fibroblasts Through the Death Receptor and Mitochondrial Pathways

Regulated cell death in acute myocardial infarction: Molecular mechanisms and therapeutic implications

Acute myocardial infarction (AMI), primarily caused by coronary atherosclerosis, initiates a series of events that culminate in the obstruction of coronary arteries, resulting in severe myocardial ischemia and hypoxia. The subsequent myocardial ischemia/reperfusion (I/R) injury further aggravates cardiac damage, leading to a decline in heart function and the risk of life-threatening complications. The complex interplay of multiple regulated cell death (RCD) pathways plays a pivotal role in the pathogenesis of AMI. Each RCD pathway is orchestrated by a symphony of molecular regulatory mechanisms, highlighting the dynamic changes and critical roles of key effector molecules. Strategic disruption or inhibition of these molecular targets offers a tantalizing prospect for mitigating or even averting the onset of RCD, thereby limiting the extensive loss of cardiomyocytes and the progression of detrimental myocardial fibrosis. This review systematically summarizes the mechanisms underlying various forms of RCD, provides an in-depth exploration of the pathogenesis of AMI through the lens of RCD, and highlights a range of promising therapeutic targets that hold the potential to revolutionize the management of AMI.

The therapeutic potential of PX-478 in a murine model of pelvic organ prolapse

BACKGROUND

Pelvic organ prolapse (POP), characterised by the downward displacement of pelvic organs, is a prevalent disorder that affects adult women. This study explored the therapeutic potential of PX-478, a selective hypoxia-inducible factor-1α (HIF-1α) inhibitor, in a murine POP model.

METHODS

A murine POP model was established through ovariectomy, mimicking oestrogen deprivation. Fifteen C57BL/6J mice were randomly assigned to control, POP, and PX-478 groups. PX-478, targeting HIF-1α, was administered intravaginally. The analysis of fibroblasts, macrophage and inflammation was performed through Masson staining, immunofluorescence, and ELISA. Collagen distribution was assessed using Sirius Red staining. Expression levels of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP-1) were determined through immunohistochemistry and western blot. Fibroblast proliferation and apoptosis were evaluated by CCK-8 assay and flow cytometry.

RESULTS

PX-478 treatment significantly reduced vaginal length, indicating a therapeutic effect on POP severity. Masson staining revealed reduced fibrotic changes and collagen disruption in PX-478-treated mice. Immunofluorescence showed increased fibroblast markers (Vimentin, α-SMA) and collagen fibres by PX-478. Sirius Red staining indicated PX-478 mitigated damage to Type I and Type III collagen fibres. PX-478 significantly reduced MMP-2 and MMP-9 expression while increased TIMP-1. In macrophages, PX-478 decreased M1 and M2 markers (CD80, CD206) and IL-18 secretion. Fibroblasts exhibited increased proliferation, reduced apoptosis, and altered MMP/TIMP expression under PX-478 influence.

CONCLUSION

PX-478 demonstrates a therapeutic potential in the mice POP model. It reduces vaginal length, attenuates fibrosis, and modulates collagen synthesis. Its immunomodulation is evident through reduced M1 and M2 macrophages and suppressed IL-18 secretion.

Genetics of Female Pelvic Organ Prolapse: Up to Date

Pelvic organ prolapse (POP) is a benign disease characterized by the descent of pelvic organs due to weakened pelvic floor muscles and fascial tissues. Primarily affecting elderly women, POP can lead to various urinary and gastrointestinal tract symptoms, significantly impacting their quality of life. The pathogenesis of POP predominantly involves nerve-muscle damage and disorders in the extracellular matrix metabolism within the pelvic floor. Recent studies have indicated that genetic factors may play a crucial role in this condition. Focusing on linkage analyses, single-nucleotide polymorphisms, genome-wide association studies, and whole exome sequencing studies, this review consolidates current research on the genetic predisposition to POP. Advances in epigenetics are also summarized and highlighted, aiming to provide theoretical recommendations for risk assessments, diagnoses, and the personalized treatment for patients with POP.

Fructose vs. glucose: modulating stem cell growth and function through sugar supplementation

In multicellular organisms, stem cells are impacted by microenvironmental resources such as nutrient availability and oxygen tension for their survival, growth, and differentiation. However, the accessibility of these resources in the pericellular environment greatly varies from organ to organ. This divergence in resource availability leads to variations in the potency and differentiation potential of stem cells. This study aimed to explore the distinct effects of glucose and fructose, as well as different oxygen tensions, on the growth dynamics, cytokine production, and differentiation of stem cells. We showed that replacing glucose with fructose subjected stem cells to stress, resulting in increased Hif1α expression and stability, which in turn led to a reduction in cell proliferation, and alterations in cytokine production. However, fructose failed to induce differentiation of human mesenchymal stem cells (hMSCs) as well as mouse fibroblasts into mature adipocytes compared to glucose, despite the upregulation of key markers of adipogenesis, including C/EBPβ, and PPARγ. Conversely, we showed that fructose induced undifferentiated mouse fibroblasts to release cytokines associated with senescence, including IL1α1, IL6, IL8, MCP1, and TNF1α, suggesting that these cells were undergoing lipolysis. Taken together, our results suggest that altering the culture conditions through changes in hexose levels and oxygen tension places considerable stress on stem cells. Additional research is required to further characterize the mechanisms governing stem cell response to their microenvironments.

Genipin ameliorates diabetic retinopathy via the HIF-1α and AGEs-RAGE pathways

BACKGROUND

Traditional Chinese medicine (TCM) is useful in disease treatment and prevention. Genipin is an active TCM compound used to treat diabetic retinopathy (DR). In this study, a network pharmacology (NP)-based approach was employed to investigate the therapeutic mechanisms underlying genipin administration in DR.

METHODS

The potential targets of DR were identified using the gene expression omnibus (GEO) database. TCM database screening and NP were used to predict the potential active targets and pathways of genipin in DR. Cell viability was tested in vitro to determine the effects of different doses of glucose and genipin on Human Retinal Microvascular Endothelial Cells (hRMECs). CCK-8, CCK-F, colony formation, CellTiter-Lum, Annexin V-FITC, wound healing, Transwell, tube-forming, reactive oxygen species (ROS), and other assay kits were used to detect the effects of genipin on hRMECs during high levels of glucose. In vivo, a streptozotocin (STZ)-mouse intraocular genipin injection (IOI.) model was used to explore the effects of genipin on diabetes-induced retinal dysfunction. Western blotting was performed to identify the cytokines involved in proliferation, apoptosis, angiogenesis, ROS, and inflammation. The protein expression of the AKT/ PI3K/ HIF-1α and AGEs/ RAGE pathways was also examined.

RESULTS

Approximately 14 types of TCM, and nearly 300 active ingredients, including genipin, were identified. The NP approach successfully identified the HIF-1α and AGEs-RAGE pathways, with the EGR1 and UCP2 genes, as key targets of genipin in DR. In the in vitro and in vivo models, we discovered that high glucose increased cell proliferation, apoptosis, angiogenesis, ROS, and inflammation. However, genipin application regulated cell proliferation and apoptosis, inhibited angiogenesis, and reduced ROS and inflammation in the HRMECs exposed to high glucose. Furthermore, the retinal thickness in the genipin-treated group was lower than that in the untreated group. AKT/ PI3K/ HIF-1α and AGEs/ RAGE signaling was increased by high glucose levels; however, genipin treatment decreased AKT/ PI3K and AGEs/ RAGE pathway expressions. Genipin also increased HIF-1α phosphorylation, oxidative phosphorylation of ATP synthesis, lipid peroxidation, and the upregulation of oxidoreductase. Genipin was found to protect HG-induced hRMECs and the retina of STZ-mice, based on; 1 the inhibition of UCP2 and Glut1 decreased intracellular glucose, and glycosylation; 2 the increased presence of HIF-1α, which increased oxidative phosphorylation and decreased substrate phosphorylation; 3 the increase in oxidative phosphorylation from ATP synthesis increased lipid peroxidation and oxidoreductase activity, and; 4 the parallel effect of phosphorylation and glycosylation on vascular endothelial growth factor (VEGF), MMP9, and Scg3.

CONCLUSION

Based on NP, we demonstrated the potential targets and pathways of genipin in the treatment of DR and confirmed its effective molecular mechanism in vitro and in vivo. Genipin protects cells and tissues from high glucose levels by regulating phosphorylation and glycosylation. The activation of the HIF-1α pathway can also be used to treat DR. Our study provides new insights into the key genes and pathways associated with the prognosis and pathogenesis of DR.

Oxygen and HIF1α-dependent SDF1 expression in primary astrocytes

In the naturally hypoxic in utero fetal environment of preterm infants, oxygen and oxygen-sensitive signaling pathways play an important role in brain development, with hypoxia-inducible factor-1α (HIF1α) being an important regulator. Early exposure to nonphysiological high oxygen concentrations by birth in room can induce HIF1α degradation and may affect neuronal and glial development. This involves the dysregulation of astroglial maturation and function, which in turn might contribute to oxygen-induced brain injury. In this study, we investigated the effects of early high oxygen exposure on astroglial maturation and, specifically, on astroglial stromal cell-derived factor 1 (SDF1) expression in vivo and in vitro. In our neonatal mouse model of hyperoxia preterm birth brain injury in vivo, high oxygen exposure affected astroglial development and cortical SDF1 expression. These results were further supported by reduced Sdf1 expression, impaired proliferation, decreased total cell number, and altered expression of astroglial markers in astrocytes in primary cultures grown under high oxygen conditions. Moreover, to mimic the naturally hypoxic in utero fetal environment, astroglial Sdf1 expression was increased after low oxygen exposure in vitro, which appears to be regulated by HIF1α activity. Additionally, the knockdown of Hif1α revealed HIF1α-dependent Sdf1 expression in vitro. Our results indicate HIF1α and oxygen-dependent chemokine expression in primary astrocytes and highlight the importance of oxygen conditions for brain development.

Cardiomyocyte crosstalk with endothelium modulates cardiac structure, function, and ischemia-reperfusion injury susceptibility through erythropoietin

Erythropoietin (EPO) exerts non-canonical roles beyond erythropoiesis that are developmentally, structurally, and physiologically relevant for the heart as a paracrine factor. The role for paracrine EPO signalling and cellular crosstalk in the adult is uncertain. Here, we provided novel evidence showing cardiomyocyte restricted loss of function in Epo in adult mice induced hyper-compensatory increases in Epo expression by adjacent cardiac endothelial cells via HIF-2α independent mechanisms. These hearts showed concentric cellular hypertrophy, elevated contractility and relaxation, and greater resistance to ischemia-reperfusion injury. Voluntary exercise capacity compared to control hearts was improved independent of any changes to whole-body metabolism or blood O2 content or delivery (i.e., hematocrit). Our findings suggest cardiac EPO had a localized effect within the normoxic heart, which was regulated by cell-specific EPO-reciprocity between cardiomyocytes and endothelium. Within the heart, hyper-compensated endothelial Epo expression was accompanied by elevated Vegfr1 and Vegfb RNA, that upon pharmacological pan-inhibition of VEGF-VEGFR signaling, resulted in a paradoxical upregulation in whole-heart Epo. Thus, we provide the first evidence that a novel EPO-EPOR/VEGF-VEGFR axis exists to carefully mediate cardiac homeostasis via cardiomyocyte-endothelial EPO crosstalk.

Detrimental Roles of Hypoxia-Inducible Factor-1α in Severe Hypoxic Brain Diseases

Hypoxia stabilizes hypoxia-inducible factors (HIFs), facilitating adaptation to hypoxic conditions. Appropriate hypoxia is pivotal for neurovascular regeneration and immune cell mobilization. However, in central nervous system (CNS) injury, prolonged and severe hypoxia harms the brain by triggering neurovascular inflammation, oxidative stress, glial activation, vascular damage, mitochondrial dysfunction, and cell death. Diminished hypoxia in the brain improves cognitive function in individuals with CNS injuries. This review discusses the current evidence regarding the contribution of severe hypoxia to CNS injuries, with an emphasis on HIF-1α-mediated pathways. During severe hypoxia in the CNS, HIF-1α facilitates inflammasome formation, mitochondrial dysfunction, and cell death. This review presents the molecular mechanisms by which HIF-1α is involved in the pathogenesis of CNS injuries, such as stroke, traumatic brain injury, and Alzheimer's disease. Deciphering the molecular mechanisms of HIF-1α will contribute to the development of therapeutic strategies for severe hypoxic brain diseases.

Establishment of a Prognostic Model for Pancreatic Cancer Based on Hypoxia-Related Genes

OBJECTIVES

Pancreatic cancer presents a formidable challenge with its aggressive nature and dismal prognosis, often hampered by elusive early symptoms. The tumor microenvironment (TME) emerges as a pivotal player in pancreatic cancer progression and treatment responses, characterized notably by hypoxia and immunosuppression. In this study, we aimed to identify hypoxia-related genes and develop a prognostic model for pancreatic cancer leveraging these genes.

METHODS

Through analysis of gene expression data from The Cancer Genome Atlas (TCGA) and subsequent GO/KEGG enrichment analysis, hypoxia-related pathways were identified. We constructed a prognostic model using lasso regression and validated it using an independent dataset.

RESULTS

Our results showed that expression levels of PLAU, SLC2A1, and CA9 exhibited significant associations with prognosis in pancreatic cancer. The prognostic model, built upon these genes, displayed robust predictive accuracy and was validated in an independent dataset. Furthermore, we found a correlation between the risk score of the prognostic model and clinical parameters of pancreatic cancer patients. At the same time, we also explored the relationship between the established hypoxia-related prognostic model and the immune microenvironment at the single-cell level. RT-qPCR results showed notable differences in the expression of hypoxia pathway-related genes between normal PANC-1 and hypoxic-treated PANC-1 cells.

CONCLUSION

Our study provides insights into the role of the hypoxic microenvironment in pancreatic cancer and offers a promising prognostic tool for clinical application.

Potential of alisols as cancer therapeutic agents: Investigating molecular mechanisms, pharmacokinetics and metabolism

Albeit remarkable achievements in anti-cancer endeavors, the prevention and treatment of cancer remain unresolved challenges. Hence, there is an urgent need to explore new and efficacious natural compounds with potential anti-cancer therapeutic agents. One such group of compounds is alisols, tetracyclic triterpene alcohols extracted from alisma orientale. Alisols play a significant role in cancer therapy as they can suppress cancer cell proliferation and migration by regulating signaling pathways such as mTOR, Bax/Bcl-2, CHOP, caspase, NF-kB and IRE1. Pharmacokinetic studies showed that alisols can be absorbed entirely, rapidly, and evenly distributed in vivo. Moreover, alisols are low in toxicity and relatively safe to take. Remarkably, each alisol can be converted into many compounds with different pathways to their anti-cancer effects in the body. Thus, alisols are regarded as promising anti-cancer agents with minimal side effects and low drug resistance. This review will examine and discuss alisols' anti-cancer molecular mechanism, pharmacokinetics and metabolism. Based on a comprehensive analysis of nearly 20 years of research, we evaluate the therapeutic potential of alisols for various types of cancer and offer insights and strategies for developing new cancer treatments.

Effect of miR-182-5p on apoptosis in myocardial infarction

Objective

This study aimed to delineate the diagnostic significance of miR-182-5p by investigating its influence on myocardial apoptosis and function, employing both in vivo and in vitro myocardial infarction models.

Methods

A rat myocardial infarction model was established. Myocardial infarction area was detected using the 2,3,5-chlorotriphenyltetrazolium (TTC) method, myocardial enzyme spectrums were measured using enzyme-linked immunosorbent assay (ELISA), myocardial structure was detected by hematoxylin and eosin (HE) staining, myocardial apoptosis was detected using the TUNEL method, and expression levels of miR-182-5p and apoptosis-related molecules were detected using real-time fluorescence quantitative PCR (qPCR) and Western blot. miR-182-5p mimics and inhibitor were transfected into rat H9C2 cardiomyocytes and mouse HL-1 cardiomyocytes to establish a hypoxia model. Cardiomyocyte viability was detected using the CCK-8 method, expression levels of apoptosis-related indicators were detected using Western blot, and caspase-3/7 activity was detected using a caspase-3/7 activity detection kit. AAV9 adeno-associated virus was used to construct an miR-182-5p overexpression virus, which was injected into mice through the tail vein to create a mouse myocardial infarction model. TTC, ELISA, HE staining, echocardiography, real-time fluorescence qPCR, and Western blot methods were used to detect the effects of AAV9-miR-182-5p on myocardial injury, myocardial function, and myocardial apoptosis levels in myocardial infarction.

Results

The rat model displayed reduced miR-182-5p expression concurrent with an increase in apoptosis. The in vitro H9C2 and HL-1 hypoxia models revealed that miR-182-5p augmented the hypoxia-induced decrease in myocardial cell viability, suppressed Bcl-2 expression, and increased Bax, Bnip3, and caspase-3/7 activity levels. The injection of AAV9-miR-182-5p significantly exacerbated myocardial tissue damage, impaired myocardial function, and enhanced apoptosis.

Conclusion

miR-182-5p escalates myocardial injury during myocardial infarction by fostering apoptosis. Interventions that aim to reduce miR-182-5p levels might be crucial in halting the progression of myocardial infarction.

Biomolecular and cellular effects in skin wound healing: the association between ascorbic acid and hypoxia-induced factor

The skin serves as a barrier to protect the body from environmental microorganisms and is the largest tissue of the body and any damage must be quickly and effectively repaired. The fundamental purpose of dermal fibroblasts is to produce and secrete extracellular matrix, which is crucial for healing wounds. The production of collagen by dermal fibroblasts requires the cofactor ascorbic acid, a free radical scavenger. In skin wounds, the presence of Ascorbic acid (AA) decreases the expression of pro-inflammatory factors and increases the expression of wound-healing factors. In addition, AA plays an important role in all three phases of wound healing, including inflammation, proliferation, and regeneration. On the other hand, growing evidence indicates that hypoxia improves the wound healing performance of mesenchymal stem cell-conditioned medium compared to the normoxic-conditioned medium. In a hypoxic-conditioned medium, the proliferation and migration of endothelial cells, fibroblasts, and keratinocytes (important cells in accelerating skin wound healing) increase. In this review, the role of AA, hypoxia, and their interactions on wound healing will be discussed and summarized by the in vitro and in vivo studies conducted to date.

SIRT6 regulates obesity-induced oxidative stress via ENDOG/SOD2 signaling in the heart

The sirtuin 6 (SIRT6) participates in regulating glucose and lipid homeostasis. However, the function of SIRT6 in the process of cardiac pathogenesis caused by obesity-associated lipotoxicity remains to be unveiled. This study was designed to elucidate the role of SIRT6 in the pathogenesis of cardiac injury due to nutrition overload-induced obesity and explore the downstream signaling pathways affecting oxidative stress in the heart. In this study, we used Sirt6 cardiac-specific knockout murine models treated with a high-fat diet (HFD) feeding to explore the function and mechanism of SIRT6 in the heart tissue during HFD-induced obesity. We also took advantage of neonatal cardiomyocytes to study the role and downstream molecules of SIRT6 during HFD-induced injury in vitro, in which intracellular oxidative stress and mitochondrial content were assessed. We observed that during HFD-induced obesity, Sirt6 loss-of-function aggravated cardiac injury including left ventricular hypertrophy and lipid accumulation. Our results evidenced that upon increased fatty acid uptake, SIRT6 positively regulated the expression of endonuclease G (ENDOG), which is a mitochondrial-resident molecule that plays an important role in mitochondrial biogenesis and redox homeostasis. Our results also showed that SIRT6 positively regulated superoxide dismutase 2 (SOD2) expression post-transcriptionally via ENDOG. Our study gives a new sight into SIRT6 beneficial role in mitochondrial biogenesis of cardiomyocytes. Our data also show that SIRT6 is required to reduce intracellular oxidative stress in the heart triggered by high-fat diet-induced obesity, involving the control of ENDOG/SOD2.

Transcriptome-wide identification of altered RNA m6A profiles in cardiac tissue of rats with LPS-induced myocardial injury

Purpose

Myocardial injury is a common complication in patients with endotoxaemia/sepsis, especially in children. Moreover, it develops through an unclear pathophysiological mechanism, and effective therapies are lacking. Recently, RNA modification, particularly N ⁶-methyladenosine (m⁶A) modification, has been found to be involved in various physiological processes and to play important roles in many diseases. However, the role of m⁶A modification in endotoxaemia/sepsis-induced myocardial injury is still in its infancy. Therefore, we attempted to construct the m⁶A modification map of myocardial injury in a rat model treated by lipopolysaccharide (LPS) and explore the role of m⁶A modification in LPS-induced myocardial injury.

Method

Myocardial injury adolescent rat model was constructed by intraperitoneal injection of LPS. m⁶A RNA Methylation Quantification Kit was used to detect overall level of m⁶A modification in rat cardiac tissue. m⁶A-specific methylated RNA immunoprecipitation followed by high-throughput sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were conducted to identify the altered m⁶A-modified genes and differentially expressed genes in cardiac tissue of rats treated by LPS and control rats (6 versus. 6). Bioinformatics was used to analyze the functions of differentially m⁶A modified genes, differentially expressed genes, and genes with both differential m⁶A modification and differential expression. qPCR was used to detect expression of m⁶A modification related enzymes.

Result

We found that the overall level of m⁶A modification in cardiac tissue of the LPS group was up-regulated compared with that of the control group. MeRIP-seq and RNA-seq results showed that genes with differential m⁶A modification, genes with differential expression and genes with both differential m⁶A modification and differential expression were closely associated with inflammatory responses and apoptosis. In addition, we found that m⁶A-related enzymes (Mettl16, Rbm15, Fto, Ythdc2 and Hnrnpg) were differentially expressed in the LPS group versus. the control group.

Conclusion

m⁶A modification is involved in the pathogenesis process of LPS-induced myocardial injury, possibly through the regulation of inflammatory response and apoptosis-related pathways. These results provide valuable information regarding the potential pathogenic mechanisms underlying LPS-induced myocardial injury.

Hypoxia-Inducible Factor 1α and Its Role in Lung Injury: Adaptive or Maladaptive

Hypoxia-inducible factors (HIFs) are transcription factors critical for the adaptive response to hypoxia. There is also an essential link between hypoxia and inflammation, and HIFs have been implicated in the dysregulated immune response to various insults. Despite the prevalence of hypoxia in tissue trauma, especially involving the lungs, there remains a dearth of studies investigating the role of HIFs in clinically relevant injury models. Here, we summarize the effects of HIF-1α on the vasculature, metabolism, inflammation, and apoptosis in the lungs and review the role of HIFs in direct lung injuries, including lung contusion, acid aspiration, pneumonia, and COVID-19. We present data that implicates HIF-1α in the context of arguments both in favor and against its role as adaptive or injurious in the propagation of the acute inflammatory response in lung injuries. Finally, we discuss the potential for pharmacological modulation of HIFs as a new class of therapeutics in the modern intensive care unit.

Platelet Lysate Therapy Attenuates Hypoxia Induced Apoptosis in Human Uroepithelial SV-HUC-1 Cells through Regulating the Oxidative Stress and Mitochondrial-Mediated Intrinsic Apoptotic Pathway

(1) Background: Ischemia/hypoxia plays an important role in interstitial cystitis/bladder pain syndrome (IC/BPS). Platelet-rich plasma (PRP) has been shown to relieve symptoms of IC/BPS by regulating new inflammatory processes and promoting tissue repair. However, the mechanism of action of PRP on the IC/BPS bladder remains unclear. We hypothesize that PRP might protect the urothelium during ischemia/hypoxia by decreasing apoptosis. (2) Methods: SV-HUC-1 cells were cultured under hypoxia for 3 h and treated with or without 2% PLTGold^® human platelet lysate (PL). Cell viability assays using trypan blue cell counts were examined. Molecules involved in the mitochondrial-mediated intrinsic apoptosis pathway, HIF1α, and PCNA were assessed by Western blot analysis. The detection of apoptotic cells and CM-H2DCFDA, an indicator of reactive oxygen species (ROS) in cells, was analyzed by flow cytometry. (3) Results: After 3 h of hypoxia, the viability of SV-HUC-1 cells and expression of PCNA were significantly decreased, and the expression of ROS, HIF1α, Bax, cytochrome c, caspase 3, and early apoptosis rate were significantly increased, all of which were attenuated by PL treatment. The addition of the antioxidant N-acetyl-L-cysteine (NAC) suppressed the levels of ROS induced by hypoxia, leading to inhibition of late apoptosis. (4) Conclusions: PL treatment could potentially protect the urothelium from apoptosis during ischemia/hypoxia by a mechanism that modulates the expression of HIF1α, the mitochondria-mediated intrinsic apoptotic pathway, and reduces ROS.

Colnoy-stimulating factor 1 positive (CSF1+ ) secretory epithelial cells induce excessive trophoblast invasion in tubal pregnancy rupture

Tubal ectopic pregnancy (TEP) occurs when an embryo aberrantly implants in the fallopian tube, leading to abortive or ruptured tubal ectopic pregnancy (AEP or REP). Poor outcomes of REP include maternal infertility or mortality. Current studies on the prevention and treatment of ruptured tubal ectopic pregnancy (REP) are unfortunately hampered by a lack of the cell spectrum and cell-cell communications in the maternal-foetal interface. Here, we investigate the mechanisms of tubal rupture through single-cell transcriptome profiling of the fallopian tube-trophoblast interface in REP, AEP and intrauterine pregnancy patients. In REP, extravillous trophoblast (EVTs) cells form a dominant cell population, displaying aggressive invasion and proliferation, with robust differentiation into three subsets. Cell communication analysis identified colony-stimulating factor 1 (CSF1), overexpressed by fallopian tube secretory epithelial cells in REP, with CSF1R on EVTs and macrophages, as a ligand/receptor pair that stimulates EVT invasion and macrophage accumulation. CSF1+ secretory epithelial cells stimulate EVTs migration and invasion, leading to a tubal rupture in REP. These results provide a mechanistic context and cellular milieu leading to tubal rupture, facilitating further study and development of therapeutics for REP in early pregnancy.

α‑hederin overcomes hypoxia‑mediated drug resistance in colorectal cancer by inhibiting the AKT/Bcl2 pathway

Currently, chemoresistance is a major challenge that directly affects the prognosis of patients with colorectal cancer (CRC). In addition, hypoxia is associated with poor prognosis and therapeutic resistance in patients with cancer. Accumulating evidence has shown that α‑hederin has significant antitumour effects and that α‑hederin can inhibit hypoxia‑mediated drug resistance in CRC; however, the underlying mechanism remains unclear. In the present study, viability and proliferation assays were used to evaluate the effect of α‑hederin on the drug resistance of CRC cells under hypoxia. Sequencing analysis and apoptosis assays were used to determine the effect of α‑hederin on apoptosis under hypoxia. Western blot analysis and reverse transcription‑quantitative PCR were used to measure apoptosis‑related protein and mRNA expression levels. Furthermore, different mouse models were established to study the effect of α‑hederin on hypoxia‑mediated CRC drug resistance in vivo. In the present study, the high expression of Bcl2 in hypoxic CRC cells was revealed to be a key factor in their drug resistance, whereas α‑hederin inhibited the expression of Bcl2 by reducing AKT phosphorylation in vitro and in vivo, and promoted the apoptosis of CRC cells under hypoxia. By contrast, overexpression of AKT reversed the effect of α‑hederin on CRC cell apoptosis under hypoxia. Taken together, these results suggested that α‑hederin may overcome hypoxia‑mediated drug resistance in CRC by inhibiting the AKT/Bcl2 pathway. In the future, α‑hederin may be used as a novel adjuvant for reversing drug resistance in CRC.

The Role of Mitochondria-Targeting miRNAs in Intracerebral Hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Arterial hypertension (AH) is most often the cause of ICH, followed by atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication and vitamin deficiencies. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. AH is difficult to treat, requires surgery and can lead to disability or death. One of the important directions in the study of the pathogenesis of ICH is mitochondrial dysfunction and its regulation. The key role of mitochondrial dysfunction in AH and atherosclerosis, as well as in the development of brain damage after hemorrhage, has been acknowledged. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that regulate a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., primarily through gene repression. There is growing evidence to support dysregulated miRNAs in various cardiovascular diseases, including ICH. Further, the realization of miRNAs within mitochondrial compartment has challenged the traditional knowledge of signaling pathways involved in the regulatory network of cardiovascular diseases. However, the role of miRNAs in mitochondrial dysfunction for ICH is still under-appreciated, with comparatively much lesser studies and investigations reported, than those in other cardiovascular diseases. In this review, we summarize the up-to-date findings on the published role miRNAs in mitochondrial function for ICH, and the potential use of miRNAs in clinical settings, such as potential therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

Engineering of the microenvironment to accelerate vascular regeneration

Blood vessels are crucial for tissue development, functionality, and homeostasis and are typically a determinant in the progression of healing and regeneration. The tissue microenvironment provides physicochemical cues that affect cellular function, and the study of the microenvironment can be accelerated by the engineering of approaches capable of mimicking various aspects of the microenvironment. In this review, we introduce the major components of the vascular niche and focus on the roles of oxygen and the extracellular matrix (ECM). We demonstrate how vascular engineering approaches enhance our understanding of the microenvironment's impact on the vasculature towards vascular regeneration and describe the current limitations and future directions towards clinical utilization.

Anthocyanin from Lycium ruthenicum Murr. in the Qaidam Basin Alleviates Ultraviolet-Induced Apoptosis of Human Skin Fibroblasts by Regulating the Death Receptor Pathway

Purpose

The study aimed to investigate the potential protective role of anthocyanin from Lycium ruthenicum Murr. in the Qaidam Basin against ultraviolet B (UVB)-induced apoptosis of human skin fibroblasts (HSFs).

Methods

HSFs cultured in vitro were randomly divided into a control group, UVB group, and anthocyanin groups (0.1, 0.5, and 1.0 mg/mL). HSFs in the UVB and anthocyanin groups were exposed to 30 mJ/cm² UVB to establish a photoaging model. Then, apoptosis rate, tumor necrosis factor-α (TNF-α), cysteinyl aspartate specific proteinase-3 (caspase-3), cysteinyl aspartate specific proteinase-7 (caspase-7), and survivin expression were evaluated.

Results

UVB irradiation can increase the apoptosis rate of HSFs and expression of TNF-α, caspase-7, and survivin. Anthocyanin pretreatment (0.1, 0.5, and 1.0 mg/mL) decreased UVB-induced apoptosis rate and TNF-α and caspase-7 expression and increased survivin expression. Compared with the control group, the apoptosis rate and expression of TNF-α, caspase-7, and survivin of anthocyanin groups in UVB-irradiated HSFs were high. Among the three doses of anthocyanin (0.1, 0.5, and 1.0 mg/mL) groups, the apoptosis rate and TNF-α expression of anthocyanin at 1.0 mg/mL were the lowest. There was no significant change in caspase-3 expression in each group.

Conclusion

Anthocyanin from Lycium ruthenicum Murr. in the Qaidam Basin could alleviate UVB-induced apoptosis by regulating the death receptor pathway.

Gou Qi Zi inhibits proliferation and induces apoptosis through the PI3K/AKT1 signaling pathway in non-small cell lung cancer

Background

Gou Qi Zi (Lycium barbarum) is a traditional herbal medicine with antioxidative effects. Although Gou Qi Zi has been used to prevent premature aging and in the treatment of non-small cell lung cancer (NSCLC), its mechanism of action in NSCLC remains unclear. The present study utilized network pharmacology to assess the potential mechanism of action of Gou Qi Zi in the treatment of NSCLC.

Methods

The TCMSP, TCMID, SwissTargetPrediction, DrugBank, DisGeNET, GeneCards, OMIM and TTD databases were searched for the active components of Gou Qi Zi and their potential therapeutic targets in NSCLC. Protein-protein interaction networks were identified and the interactions of target proteins were analyzed. Involved pathways were determined by GO enrichment and KEGG pathway analyses using the Metascape database, and molecular docking technology was used to study the interactions between active compounds and potential targets. These results were verified by cell counting kit-8 assays, BrdU labeling, flow cytometry, immunohistochemistry, western blotting, and qRT-PCR.

Results

Database searches identified 33 active components in Gou Qi Zi, 199 predicted biological targets and 113 NSCLC-related targets. A network of targets of traditional Chinese medicine compounds and potential targets of Gou Qi Zi in NSCLC was constructed. GO enrichment analysis showed that Gou Qi Zi targeting of NSCLC was mainly due to the effect of its associated lipopolysaccharide. KEGG pathway analysis showed that Gou Qi Zi acted mainly through the PI3K/AKT1 signaling pathway in the treatment of NSCLC. Molecular docking experiments showed that the bioactive compounds of Gou Qi Zi could bind to AKT1, C-MYC and TP53. These results were verified by experimental assays.

Conclusion

Gou Qi Zi induces apoptosis and inhibits proliferation of NSCLC in vitro and in vivo by inhibiting the PI3K/AKT1 signaling pathway.

HIF-1α/BNIP3L induced cognitive deficits in a mouse model of sepsis-associated encephalopathy

Objective

Sepsis Associated Encephalopathy (SAE) is a common complication in critically ill patients and perioperative period, but its pathogenesis is still unclear. This study aimed to explore the effect of the HIF-1α (hypoxia-inducible factor-1α)/BNIP3L (Bcl-2/adenovirus E1B 19-kDa interaction protein) signaling pathway on SAE.

Methods

C57BL/6J male mice were divided into four groups, using a random number table method: control group, sham group, sepsis group, sepsis+HIF-1α activity inhibitor (echinomycin) group. Sepsis was induced by cecal ligation and puncture (CLP). At 24 h after surgery, brain tissue was sampled. HE was staining to observe changes in the hippocampus structure. Fluoroscopy observes changes in mitochondrial structure. Western blot, QT-PCR, and immunofluorescence were used to assess the amount of expression of HIF-1α and BNIP3L in the hippocampus and mitochondrion of hippocampus neurons. Observation of neuronal apoptosis by TUNEL staining. Seven days after surgery, mice were tested in a Morris water maze test to assess cognitive function after CLP.

Results

Our results show that CLP-induced hippocampus-dependent cognitive deficits were accompanied with increased HIF 1a and decreased BNIP3L, increased protein levels of TNF-α, IL-6, and IL-β, and damage to mitochondrial structures and neuronal apoptosis in the hippocampus. In addition, administration of echinomycin rescues cognitive deficits, ameliorates HIF-1α and BNIP3L-mediated neuronal pyroptosis and damaged mitochondrial structures, and decreases the expression of TNF-α and IL-6 in the hippocampus.

Conclusions

HIF-1α and the BNIP3L promote mitochondrial damage, and neuronal apoptosis and the expression of inflammatory factors may be the mechanism of SAE in critically ill patients and perioperative period.

Polystyrene microplastics induce apoptosis and necroptosis in swine testis cells via ROS/MAPK/HIF1α pathway

Microplastics (MPs) generally refer to the plastic fragments or particles smaller than 5 mm in diameter, which are closely concerned due to their widespread presence in the environment. Recent studies have shown that MPs have a serious threat on the reproductive health of organisms. Pigs are often selected as the model animals because of their high similarity to human tissues and organs. However, there are no reports on the effects and mechanisms of MPs exposure on swine germ cells. In the present study, we established swine testis (ST) cell models exposed to 250, 500, and 1000 μg/ml polystyrene microplastics (PS-MPs, 1-10 μm), respectively. The findings revealed that PS-MPs reduced cell viability dose-dependently. Acridine orange/ethidium bromide staining and flow cytometry results indicated the occurrence of apoptosis and necrosis in ST cells under PS-MPs exposure, and the expression changes of relevant marker genes (B-cell lymphoma-2, Bcl-2 Associated X, Caspase-3, Caspase-9, Receptor-interacting protein kinase 1, Receptor-interacting protein kinase 3, Mixed lineage kinase domain-like, and Caspase-8) were clarified via quantitative real-time PCR and western blot. Further mechanistic studies found that PS-MPs treatment induced excessive intracellular reactive oxygen species (ROS) production, which promoted the phosphorylation of mitogen-activated protein kinase (MAPK) pathway-related genes (P38, c-Jun N-terminal kinase, extracellular regulated protein kinases) and activated the downstream gene hypoxia-inducible factor (HIF1α). In conclusion, our study suggests that PS-MPs treatment causes apoptosis and necroptosis in ST cells via ROS/MAPK/HIF1α signaling pathway.

Melatonin inhibits NaIO3-induced ARPE-19 cell apoptosis via suppression of HIF-1α/BNIP3-LC3B/mitophagy signaling

Background

Age-related macular degeneration (AMD) leads to gradual central vision loss and eventual irreversible blindness. Melatonin, an endogenous hormone, exhibits anti-inflammatory and antitumor effects; however, the role it plays in AMD remains unclear. Herein, we investigated the anti-AMD molecular mechanism of melatonin after sodium iodate (NaIO3) treatment of ARPE-19 cells in vitro and in animal models with the goal of improving the therapeutic effect.

Results

The in vitro results showed that melatonin protected against NaIO₃-induced cell viability decline, mitochondrial dysfunction and apoptosis in ARPE-19 cells, and melatonin also alleviated NaIO₃-induced reactive oxygen species (ROS) production, mitochondrial dysfunction and mitophagy activation. Melatonin reduced NaIO₃-induced mitophagy activation through HIF-1α-targeted BNIP3/LC3B transcription, whereas ROS inhibition realized with N-acetylcysteine (NAC, a ROS inhibitor) combined with melatonin reduced the effect of NaIO₃ on mitophagy. An animal model of AMD was established to confirm the in vitro data. Mouse tail vein injection of NaIO₃ and melatonin was associated with enhanced repair of retinal layers within 7 days, as observed by optical coherence tomography (OCT) and hematoxylin and eosin (H&E) staining. A reduction in BNIP3 and HIF-1α levels, as determined by immunohistochemistry (IHC) assay, was also observed.

Conclusions

These results indicate that melatonin attenuated NaIO₃-induced mitophagy of ARPE-19 cells via reduction in ROS-mediated HIF-1α targeted BNIP3/LC3B signaling in vitro and in vivo. Melatonin may be a potential therapeutic drug in the treatment of AMD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00879-3.

Effects of NRF-1 and PGC-1α cooperation on HIF-1α and rat cardiomyocyte apoptosis under hypoxia

BACKGROUND

Hypoxia is a primary inducer of cardiomyocyte injury, its significant marker being hypoxia-induced cardiomyocyte apoptosis. Nuclear respiratory factor-1 (NRF-1) and hypoxia-inducible factor-1α (HIF-1α) are transcriptional regulatory elements implicated in multiple biological functions, including oxidative stress response. However, their roles in hypoxia-induced cardiomyocyte apoptosis remain unknown. The effect HIF-1α, together with NRF-1, exerts on cardiomyocyte apoptosis also remains unclear.

METHODS

We established a myocardial hypoxia model and investigated the effects of these proteins on the proliferation and apoptosis of rat cardiomyocytes (H9C2) under hypoxia. Further, we examined the association between NRF-1 and HIF-1α to improve the current understanding of NRF-1 anti-apoptotic mechanisms.

RESULTS

The results show that NRF-1 and HIF-1α are important anti-apoptotic molecules in H9C2 cells under hypoxia, although their regulatory mechanisms differ. NRF-1 could bind to the promoter region of Hif1a and negatively regulate its expression. Additionally, HIF-1β exhibited competitive binding with NRF-1 and HIF-1α, demonstrating a synergism between NRF-1 and the peroxisome proliferator-activated receptor-gamma coactivator-1α.

CONCLUSION

These results indicate that cardiomyocytes can regulate different molecular patterns to tolerate hypoxia, providing a novel methodological framework for studying cardiomyocyte apoptosis under hypoxia.

Sulforaphane Acts Through NFE2L2 to Prevent Hypoxia-Induced Apoptosis in Porcine Granulosa Cells via Activating Antioxidant Defenses and Mitophagy

In mammals, a vast majority of ovarian follicles undergo atresia, which is caused by granulosa cell (GC) apoptosis. GCs in follicles are exposed to low oxygen. Hypoxia triggers reactive oxygen species (ROS) generation, which leads to cell oxidative stress and apoptosis. Sulforaphane (SFN), a phytochemical isothiocyanate enriched in cruciferous vegetables, has exhibited a crucial role in mitigating oxidative stress. To explore the effect of SFN on porcine GC apoptosis in a hypoxic environment, we handled the established hypoxia model (1% O₂) of cultured porcine GCs with SFN. Results showed that SFN rescued hypoxia-induced apoptosis and viability of GCs. Meanwhile, SFN increased the expression of antioxidant enzymes and reduced the accumulation of ROS in GC cytoplasm and mitochondria under hypoxia. Mechanically, SFN activated the transcription factor of redox-sensitive nuclear factor-erythroid 2-related factor 2 (NFE2L2) entering the nucleus, further inducing mitophagy and increased antioxidant capacity, finally alleviating the adverse effect of hypoxia on porcine GCs. In conclusion, SFN inhibited hypoxia-evoked GC apoptosis by activating antioxidant defenses and mitophagy through NFE2L2. New targets may be provided for regulating follicular development and atresia by these findings.

In vitro Cartilage Regeneration Regulated by a Hydrostatic Pressure Bioreactor Based on Hybrid Photocrosslinkable Hydrogels

Because of the superior characteristics of photocrosslinkable hydrogels suitable for 3D cell-laden bioprinting, tissue regeneration based on photocrosslinkable hydrogels has become an important research topic. However, due to nutrient permeation obstacles caused by the dense networks and static culture conditions, there have been no successful reports on in vitro cartilage regeneration with certain thicknesses based on photocrosslinkable hydrogels. To solve this problem, hydrostatic pressure (HP) provided by the bioreactor was used to regulate the in vitro cartilage regeneration based on hybrid photocrosslinkable (HPC) hydrogel. Chondrocyte laden HPC hydrogels (CHPC) were cultured under 5 MPa HP for 8 weeks and evaluated by various staining and quantitative methods. Results demonstrated that CHPC can maintain the characteristics of HPC hydrogels and is suitable for 3D cell-laden bioprinting. However, HPC hydrogels with concentrations over 3% wt% significantly influenced cell viability and in vitro cartilage regeneration due to nutrient permeation obstacles. Fortunately, HP completely reversed the negative influences of HPC hydrogels at 3% wt%, significantly enhanced cell viability, proliferation, and extracellular matrix (ECM) deposition by improving nutrient transportation and up-regulating the expression of cartilage-specific genes, and successfully regenerated homogeneous cartilage with a thickness over 3 mm. The transcriptome sequencing results demonstrated that HP regulated in vitro cartilage regeneration primarily by inhibiting cell senescence and apoptosis, promoting ECM synthesis, suppressing ECM catabolism, and ECM structure remodeling. Evaluation of in vivo fate indicated that in vitro regenerated cartilage in the HP group further developed after implantation and formed homogeneous and mature cartilage close to the native one, suggesting significant clinical potential. The current study outlines an efficient strategy for in vitro cartilage regeneration based on photocrosslinkable hydrogel scaffolds and its in vivo application.

The Key Network of mRNAs and miRNAs Regulated by HIF1A in Hypoxic Hepatocellular Carcinoma Cells

Purpose: Hypoxia plays an essential role in the progression of hepatocellular carcinoma (HCC), whereas hypoxia inducible factor-1 (HIF-1) is the key transcription factor allowing HCC to survive hypoxia. The aim of this study was to define the essential mRNAs and miRNAs regulated by HIF1A and dissect their functions, interactions, and tumor-infiltrating immune cells in HCC. Methods: A human HCC cell line HepG2 was used as a cell model of HCC. The CRISPR/Cas9 system was used to knock out HIF1A in HepG2 cells, and RNA sequencing was utilized to characterize differentially expressed mRNAs and miRNAs in the HIF1A-knockout HepG2 cells; the identified candidates were then analyzed by GO annotation and KEGG pathway enrichment to study their function and establish a PPI network. Quantitative (q) PCR was used to verify if there were significant differences in the expression of mRNAs, and the association of the selected mRNAs expression with immune cell infiltration levels was further analyzed using The Cancer Genome Atlas (TCGA) pan-cancer data. Results: Using RNA-sequencing, we discovered that there were 1535 mRNAs differentially expressed (adjusted p < 0.05, |fold change|>1.5) in the HIF1A-knockout HepG2 cells, among which there were 644 mRNAs upregulated and 891 mRNAs downregulated. GO annotation and KEGG pathway enrichment showed that these mRNAs were involved in glycolysis/gluconeogenesis, PI3K-Akt signaling pathways, and HIF-1 signaling pathways. In addition, we found that there were 309 miRNAs differentially expressed (adjusted p < 0.05, |fold change|>1.5) in the HIF1A-knockout HepG2 cells, of which there were 213 miRNAs upregulated and 96 miRNAs downregulated. Our further analyses uncovered that these miRNA putative targets were involved in the hippo signaling pathway, axon guidance, and tight junction. Moreover, the construction and analysis of the PPI network showed that OASL, IL6, and TAF1 were recognized as hub genes with the highest connectivity degrees. Importantly, in the HIF1A-knockout HepG2 cells, our qRT-PCR data confirmed the selected mRNA changes revealed by RNA-sequencing, and with TCGA pan-cancer data, we revealed that the expressional levels of these three genes, LUM, SCOC, and CCL2, were associated with immune cell infiltration levels. Conclusion: The identified potential key network of mRNAs and miRNAs regulated by HIF1A in the HCC cells suggests a key role of HIF1A in the tumorigenesis of HCC.

Dapagliflozin Attenuates Contrast-induced Acute Kidney Injury by Regulating the HIF-1α/HE4/NF-κB Pathway

ABSTRACT

Contrast-induced acute kidney injury (CI-AKI) causes clinically acquired nephropathy in patients who undergo coronary interventions. Hypoxic injury to proximal tubular epithelial cells is a pathological mechanism of CI-AKI. Previous studies have shown that hypoxia activates HIF-1α/HE4/NF-κB to enhance renal fibrosis, and the SGLT-2 inhibitor luseogliflozin inhibits hypoxia-inducible factor (HIF)-1α expression to reduce the progression of diabetic nephropathy. However, the therapeutic effects and mechanisms of SGLT-2 inhibitors on CI-AKI are unclear. We explored the role of the HIF-1α/HE4/NF-κB pathway in CI-AKI and how dapagliflozin effectively treats CI-AKI by inhibiting this pathway. In vitro, cells were divided into the control, hypoxia, hypoxia + dapagliflozin, and hypoxia + pSilencer-HIF-1α groups. Cellular hypoxia, apoptosis, and related protein expression were evaluated by immunofluorescence, western blotting, and flow cytometry, respectively. Dapagliflozin significantly decreased oxygen consumption, HIF-1α, human epididymis protein 4 (HE4), NF-κB expression, and apoptotic cells compared with the control (P < 0.01). In vivo, rats were divided into the control (C), diabetes (D), diabetes + contrast media, and diabetes + contrast media + dapagliflozin groups. Rats in the latter 2 groups were treated with dapagliflozin for 2 days. CI-AKI was induced by intravenously injecting indomethacin, N-nitro-l-arginine methyl ester, and iohexol. The effects of dapagliflozin on CI-AKI rats were elucidated by assessing renal function, H&E staining, and immunohistochemistry. Serum creatinine, urea nitrogen, TUNEL-positive tubular cells, HIF-1α, HE4, NF-κB expression, and histopathological scores were increased in diabetes + contrast media rats compared with C, D, and diabetes + dapagliflozin + contrast media rats (P < 0.01). Thus, dapagliflozin may ameliorate CI-AKI through suppression of HIF-1α/HE4/NF-κB signaling in vitro and in vivo.

LRG-1 promotes fat graft survival through the RAB31-mediated inhibition of hypoxia-induced apoptosis

Autologous adipose tissue is an ideal soft tissue filling material, and its biocompatibility is better than that of artificial tissue substitutes, foreign bodies and heterogeneous materials. Although autologous fat transplantation has many advantages, the low retention rate of adipose tissue limits its clinical application. Here, we identified a secretory glycoprotein, leucine‐rich‐alpha‐2‐glycoprotein 1 (LRG‐1), that could promote fat graft survival through RAB31‐mediated inhibition of hypoxia‐induced apoptosis. We showed that LRG‐1 injection significantly increased the maintenance of fat volume and weight compared with the control. In addition, higher fat integrity, more viable adipocytes and fewer apoptotic cells were observed in the LRG‐1‐treated groups. Furthermore, we discovered that LRG‐1 could reduce the ADSC apoptosis induced by hypoxic conditions. The mechanism underlying the LRG‐1‐mediated suppression of the ADSC apoptosis induced by hypoxia was mediated by the upregulation of RAB31 expression. Using LRG‐1 for fat grafts may prove to be clinically successful for increasing the retention rate of transplanted fat.

Hypoxia Induces Apoptosis of Microglia BV2 by Upregulating Kir2.1 to Activate Mitochondrial-Related Apoptotic Pathways

Aim

To explore the role of Kir2.1 in hypoxia-induced microglial apoptosis.

Methods

BV2 microglial cell lines were cultured and treated with ML133 hydrochloride, a Kir2.1 channel blocker, for 23 h and with 500 μmol/L of CoCl₂ for 8 h. Cells were divided into the control, CoCl₂ (hypoxia-induced model), and CoCl₂+ML133 (hypoxia-induced model established after ML133 pretreatment) groups. Cell activity was assessed using the CCK-8 technique. The membrane potential and Kir2.1 current of BV2 were evaluated with the whole-cell patch-clamp technique. The protein levels and mRNA levels of Kir2.1, apoptotic proteins Bax and caspase-3, and antiapoptotic protein Bcl-2 in BV2 cells were evaluated via immunofluorescence, Western blot analysis, and real-time quantitative reverse transcription. The apoptosis rate of BV2 cells was detected via flow cytometry.

Results

CCK-8 analysis showed that the cell activity of each group increased initially and then decreased. The 2 h intervention group had the highest cell activity, and that of the 8 h group was >90%. Hence, there was a significant difference in the results (P < 0.05). Western blot analysis revealed that the expression of cleaved caspase-3 significantly increased in the 8 h group compared with the 0 h group. Compared with the control group, the expression of Kir2.1 and mRNA in the CoCl₂ group increased. Thus, hypoxia could upregulate the expression of Kir2.1. The whole-cell patch-clamp results showed that the Kir2.1 channel current amplitude of the CoCl₂ group increased compared with that of the control group. Therefore, hypoxia could enhance Kir2.1 function. The apoptosis rate of the CoCl₂ group was significantly higher than that of the control group. Further, the ML133 group had a significantly lower apoptosis rate than the CoCl₂ group. The expression of apoptotic proteins Bax and cleaved caspase-3 increased in the CoCl₂ group, and that of the antiapoptotic protein Bcl-2 decreased. The expression of apoptotic proteins Bax and cleaved caspase-3 reduced in the CoCl₂+ML133 group, whereas that of the antiapoptotic protein Bcl-2 increased.

Conclusion

Hypoxia can induce microglia BV2 apoptosis accompanied by the upregulation of Kir2.1 and mRNA expression levels and an increase in the Kir2.1 current. Moreover, ML133 can inhibit hypoxia-induced BV2 cell apoptosis. Hence, Kir2.1 may be involved in the process of hypoxia-induced BV2 cell apoptosis.

Changes in the Mitochondrial Dynamics and Functions Together with the mRNA/miRNA Network in the Heart Tissue Contribute to Hypoxia Adaptation in Tibetan Sheep

This study aimed to provide insights into molecular regulation and mitochondrial functionality under hypoxia by exploring the mechanism of adaptation to hypoxia, blood indexes, tissue morphology, mRNA/miRNA regulation, mitochondrial dynamics, and functional changes in Tibetan sheep raised at different altitudes. With regard to blood indexes and myocardial morphology, the HGB, HCT, CK, CK-MB, LDH, LDH1, SOD, GPX, LDL level, and myocardial capillary density were significantly increased in the sheep at higher altitudes (p < 0.05). The RNA-seq results suggested the DEmRNAs and DEmiRNAs are mainly associated with the PI3K-Akt, Wnt, and PPAR signaling pathways and with an upregulation of oncogenes (CCKBR, GSTT1, ARID5B) and tumor suppressor factors (TPT1, EXTL1, ITPRIP) to enhance the cellular metabolism and increased ATP production. Analyzing mRNA−miRNA coregulation indicated the mitochondrial dynamics and functions to be significantly enriched. By analyzing mitochondrial dynamics, mitochondrial fusion was shown to be significantly increased and fission significantly decreased in the heart with increasing altitude (p < 0.05). There was a significant increase in the density of the mitochondria, and a significant decrease in the average area, aspect ratio, number, and width of single mitochondrial cristae with increasing altitudes (p < 0.05). There was a significant increase in the NADH, NAD+ and ATP content, NADH/NAD+ ratio, and CO activity, while there was a significant decrease in SDH and CA activity in various tissues with increasing altitudes (p < 0.05). Accordingly, changes in the blood indexes and myocardial morphology of the Tibetan sheep were found to improve the efficiency of hemoglobin-carrying oxygen and reduce oxidative stress. The high expression of oncogenes and tumor suppressor factors might facilitate cell division and energy exchange, as was evident from enhanced mitochondrial fission and OXPHOS expression; however, it reduced the fusion and TCA cycle for the further rapid production of ATP in adaptation to hypoxia stress. This systematic study has for the first time delineated the mechanism of hypoxia adaptation in the heart of Tibetan sheep, which is significant for improving the ability of the mammals to adapt to hypoxia and for studying the dynamic regulation of mitochondria during hypoxia conditions.

Up-regulation of PUMA caused the activation of p53 phosphorylation and acetylation, enhancing the interaction between PUMA and Bcl-X and mediating arsenic-induced apoptosis

Arsenic is a toxic metalloid vastly dispersed all over the occupational environments, manifesting multiple adverse health issues related to apoptosis. PUMA (p53 up-regulated modulator of apoptosis) is a crucial member of the Bcl-2 protein family and plays a key role in pro-apoptosis. The purpose of this work was to determine whether inorganic arsenic (NaAsO₂) and its metabolites influenced the expression of PUMA in vivo and vitro, followed by investigating the mechanisms. RNA was extracted from serum and used to determine the expression of PUMA in vivo. The urine samples performed arsenic speciation analysis. This trial tested three-dose proportions in two cell lines (A549: 20, 40, 60 μM/L; 16HBE: 1.5, 3.0, 4.5 μM/L), respectively. According to the results of qRT-PCR and western blotting, NaAsO₂ caused the overexpression of PUMA, not its metabolites. Furthermore, NaAsO₂ induced phosphorylation of p53 at Ser315, 376, 392, and Thr55, and acetylation of p53 at K370, 382 with a dose-response relationship, suggesting the contribution of PUMA up-regulation to p53 phosphorylation and acetylation. CCK-8, JC-1 (5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetramethylbenzimi-dazolylcarbocyanine iodide), Hoechst33342/PI and the caspase3 and PARP1 blots were utilized to reveal apoptosis responding to NaAsO₂ exposure. The co-immunoprecipitation assay showed that the interaction between PUMA and Bcl-X enhanced in intensity responding to NaAsO₂ exposure, disrupting the complexes of Bcl-X with other pro-survival Bcl-2-related proteins. To our knowledge, we first reported that NaAsO₂ activated phosphorylation of p53 at Ser315, 376, and Thr55, as well as acetylation of p53 at K370.

Inhibition of the HIF-1α/BNIP3 pathway has a retinal neuroprotective effect

Retinal ischemia is a leading cause of irreversible blindness worldwide. Inner retinal dysfunction including loss of retinal ganglion cells is encountered in a number of retinal ischemic disorders. We previously reported administration of two different hypoxia-inducible factor (HIF) inhibitors exerted neuroprotective effects in a murine model of retinal ischemia/reperfusion (I/R) which mimics these disorders, as inner retinal degeneration could be involved in pathological HIF induction. However, this notion needs further investigation. Therefore, in this study, we attempted to use retina-specific Hif-1α conditional knockout (cKO) mice to uncover this notion more clearly under the same condition. Hif-1α cKO mice showed inner retinal neurodegeneration to a lesser extent than control mice. Hif-1α depletion in a murine 661W retinal cell line reduced cell death under pseudohypoxic and hypoxic conditions. Among hypoxia-related genes, the expression of BCL2 19 kDa protein-interacting protein 3 (Bnip3) was substantially upregulated in the inner retinal layer after retinal I/R. In this regard, we further examined Bnip3 depletion in retinal neurons in vitro and in vivo and found the similar neuroprotective effects. Our results support the notion that the HIF-1α/BNIP3 pathway may have a critical role in inner retinal neurodegeneration, which can be linked with the development of new promising therapeutics for inner retinal ischemic disorders.

Electrospun meshes intrinsically promote M2 polarization of microglia under hypoxia and offer protection from hypoxia-driven cell death

In this study, we offer new insights into the contrasting effects of electrospun fiber orientation on microglial polarization under normoxia and hypoxia, and establish for the first time, the intrinsically protective roles of electrospun meshes against hypoxia-induced microglial responses. First, resting microglia were cultured under normoxia on poly(caprolactone) fibers possessing two distinctly different fiber orientations. Matrix-guided differences in cell shape/orientation and differentially expressed Rho GTPases (RhoA, Rac1, Cdc42) were well-correlated with the randomly oriented fibers inducing a pro-inflammatory phenotype and the aligned fibers sustaining a resting phenotype. Upon subsequent hypoxia induction, both sets of meshes offered protection from hypoxia-induced damage by promoting a radical phenotypic switch and beneficially altering the M2/M1 ratio to different extents. Compared to 2D hypoxic controls, meshes significantly suppressed the expression of pro-inflammatory markers (IL-6, TNF-α) and induced drastically higher expression of anti-inflammatory (IL-4, IL-10, VEGF-189) and neuroprotective (Nrf-2) markers. Consistent with this M2 polarization, the expression of Rho GTPases was significantly lower in the mesh groups under hypoxia compared to normoxic culture. Moreover, meshes-particularly with aligned fibers-promoted higher cell viability, suppressed caspase 3/8 and LC-3 expression and promoted LAMP-1 and LAMP-2 expression, which suggested the mitigation of apoptotic/autophagic cell death via a lysosomal membrane-stabilization mechanism. Notably, all protective effects under hypoxia were observed in the absence of additional soluble cues. Our results offer promise for leveraging the intrinsic therapeutic potential of electrospun meshes in degenerative diseases where microglial dysfunction, hypoxia and inflammation are implicated.

Metformin Attenuates Hypoxia-induced Endothelial Cell Injury by Activating the AMP-Activated Protein Kinase Pathway

ABSTRACT

Metformin reduces the incidence of cardiovascular diseases, and potential underlying mechanisms of action have been suggested. Here, we investigated the role of metformin in endothelial cell injury and endothelial-mesenchymal transition (EndMT) induced by hypoxia. All experiments were performed in human cardiac microvascular endothelial cells (HCMECs). HCMECs were exposed to hypoxic conditions for 24, 48, 72, and 96 hours, and we assessed the cell viability by cell counting kit 8; metformin (2, 5, 10, and 20 mmol/L) was added to the cells after exposure to the hypoxic conditions for 48 hours. The cells were randomly divided into the control group, hypoxia group, hypoxia + metformin group, hypoxia + control small interfering RNA group, hypoxia + small interfering Prkaa1 (siPrkaa1) group, and hypoxia + siPrkaa1 + metformin group. Flow cytometry and cell counting kit 8 were used to monitor apoptosis and assess cell viability. Immunofluorescence staining was used to identify the CD31+/alpha smooth muscle actin+ double-positive cells. Quantitative real-time-PCR and Western blot were used for mRNA and protein expression analyses, respectively. Hypoxia contributed to endothelial injuries and EndMT of HCMECs in a time-dependent manner, which was mainly manifested as decreases in cell viability, increases in apoptotic rate, and changes in expression of apoptosis-related and EndMT-related mRNAs and proteins. Furthermore, metformin could attenuate the injuries and EndMT caused by hypoxia. After metformin treatment, phosphorylated-AMPK (pAMPK) and p-endothelial nitric oxide synthase expression increased, whereas p-mammalian target of rapamycin expression decreased. However, results obtained after transfection with siPrkaa1 were in contrast to the results of metformin treatment. In conclusion, metformin can attenuate endothelial injuries and suppress EndMT of HCMECs under hypoxic conditions because of its ability to activate the AMPK pathway, increase p-AMPK/AMP-activated protein kinase, and inhibit mammalian target of rapamycin.

Proteomic analysis reveals rotator cuff injury caused by oxidative stress

Background and aims:

Rotator cuff tendinopathy is common and is related to pain and dysfunction. However, the pathological mechanism of rotator cuff injury and shoulder pain is unclear. Objective: to investigate the pathological mechanism of rotator cuff injury and shoulder pain, and screen out the marker proteins related to rotator cuff injury by proteomics.

Methods:

Subacromial synovium specimens were collected from patients undergoing shoulder arthroscopic surgery. The experimental group were patients with rotator cuff repair surgery, and the control group were patients with habitual dislocation of the shoulder joint. Pathological examination was performed, and then followed by non-labeled quantitative proteomic detection. Finally, from analysis of the biological information of the samples, specific proteins related to rotator cuff injury and shoulder pain were deduced by functional analysis of differential proteins.

Results:

All the patients in experimental groups were representative. A large number of adipocytes and inflammatory cells were found in the pathological sections of the experimental group; the proteomics analysis screen identified 80 proteins with significant differences, and the analysis of protein function revealed that S100A11 (p = 0.011), PLIN4 (p = 0.017), HYOU1 (p = 0.002) and CLIC1 (p = 0.007) were closely related to oxidative stress and chronic inflammation.

Conclusion:

Rotator cuff injury is closely related to oxidative stress and chronic inflammatory response, and the results suggest that the expression of S100A11, PLIN4, HYOU1 and CLIC1 in the synovium of rotator cuff injury provides a new marker for the study of its pathological mechanism.

A paradox: Fe2+-containing agents decreased ROS and apoptosis induced by CoNPs in vascular endothelial cells by inhibiting HIF-1α

Cobalt nanoparticles (CoNPs) released from hip joint implants are known to have a toxic effect on several organs probably through increasing reactive oxygen species (ROS). Ferrous ion (Fe²⁺) is well-known to enhance oxidative stress by catalysing the production of ROS. However, in our pilot study, we found that Fe²⁺ conversely inhibited the ROS production induced by CoNPs. To elucidate the underlying mechanism, the present study treated vascular endothelial HUVEC and HMEC-1 cells with CoNPs alone or in combination with ferrous lactate [Fe(CH₃CHOHCOO)₂], ferrous succinate [Fe(CH₂COO)₂], and ferrous chloride (FeCl₂). CoNP toxicity was evaluated by measuring cell viability, rate of apoptosis and lactose dehydrogenase (LDH) release, and intracellular ROS levels. Treatment with CoNPs decreased cell viability, LDH release, and ROS production and increased apoptosis. CoNPs increased hypoxia-inducible factor-1α (HIF-1α) protein level and mRNA levels of vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1) downstream of HIF-1α signalling. Silencing HIF-1α attenuated CoNP toxicity, as seen by recovery of cell viability, LDH release, and ROS levels and reduced apoptosis. CoNPs caused a pronounced reduction of Fe²⁺ in cells, but supplementation with Fe(CH₃CHOHCOO)₂, Fe(CH₂COO)₂, and FeCl₂ restored Fe²⁺ levels and inhibited HIF-1α activation. Moreover, all three Fe²⁺-containing agents conferred protection from CoNPs; Fe(CH₃CHOHCOO)₂ and Fe(CH₂COO)₂ more effectively than FeCl₂. In summary, the present study revealed that CoNPs exert their toxicity on human vascular endothelial cells by depleting intracellular Fe²⁺ level, which causes activation of HIF-1α signalling. Supplements of Fe²⁺, especially in the form of Fe(CH3CHOHCOO)₂ and Fe(CH₂COO)₂, mitigated CoNP toxicity.

Protective Effects of Adiponectin against Cobalt Chloride-Induced Apoptosis of Smooth Muscle Cells via cAMP/PKA Pathway

Adiponectin (APN) is an adipokine secreted from adipose tissue and exhibits biological functions such as microcirculation-regulating, hearing-protective, and antiapoptotic. However, the effect of APN on the apoptosis of spiral arterial smooth muscle cells (SMCs) under hypoxic conditions in vitro is not clear. We used cobalt chloride (CoCl₂) to simulate chemical hypoxia in vitro, and the SMCs were pretreated with APN and then stimulated with CoCl₂. The viability of cells and apoptosis were assessed by CCK-8 and flow cytometry, respectively. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) levels, cAMP level, and the activity of PKA were detected by ELISA. Protein expression and localization were studied by Western blot and immunofluorescence analysis. In the present study, we found that APN exhibits antiapoptosis effects. CoCl₂ exhibited decreased cell viability, increased apoptosis and MDA levels, and decreased SOD activity in a concentration-dependent manner, compared with the control group. Moreover, CoCl₂ upregulated the expression levels of Bax and cleaved caspase-3 and then downregulated Bcl-2 levels in a time-dependent manner. Compared with the CoCl₂ group, the group pretreated with APN had increased cell viability, SOD activity, PKA activity, cAMP level, and PKA expression, but decreased MDA levels and apoptosis. Lastly, the protective effect of APN was blocked by cAMP inhibitor SQ22536 and PKA inhibitor H 89. These results showed that APN protected SMCs against CoCl₂-induced hypoxic injury via the cAMP/PKA signaling pathway.

Histological evaluation of peri-implant mucosal and gingival tissues in peri-implantitis, peri-implant mucositis and periodontitis patients: a cross-sectional clinical study

Objective: Aim of present study was to evaluate gingival tissue samples obtained from healthy and diseased sites of teeth and dental implants in terms of hypoxia and collagenase activity.Methods: Four study groups were created as Group-1; healthy individuals (H), Group-2; periodontitis patients with stage 3 grade B (P), Group-3; patients with peri-implant mucositis. Group-4; patients with peri-implantitis (P-IMP). Plaque index (PI), gingival index (GI) and probing pocket depth (PPD) were recorded. Gingival and peri-implant mucosal biopsies were obtained. Fibroblast and inflammatory cells were counted. Hypoxia-inducible factor (HIF)-1α, prolyl hydroxylase (PH), matrix metalloproteinase (MMP)-8, tissue inhibitor of MMPs (TIMP)-1, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) levels were determined via immunohistochemistry.Results: Healthy controls had highest fibroblast cell counts and lowest inflammatory cell counts compared to other groups. Peri-implantitis and periodontitis samples had similar fibroblast and inflammatory cell counts, while peri-implant mucositis had higher fibroblast cells and lowered inflammatory cells compared to periodontitis and peri-implantitis samples. HIF-1α, COX-2 and iNOS levels were lowest in healthy controls and increased in other groups. Peri-implant mucositis samples had significantly lower expressions of HIF-1α, COX-2 and iNOS compared to peri-implantitis and periodontitis groups. PH expressions were lower in periodontitis and peri-implantitis groups compared to healthy controls and peri-implant mucositis groups. MMP-8 levels were lower in healthy group compared to other groups while levels were similar in periodontitis, peri-implant mucositis and peri-implantitis groups. TIMP levels were similar in groups.Conclusion: Periodontitis, peri-implantitis, and peri-implant mucositis samples exhibited higher inflammation and lower fibroblast cell counts and tend to have increased tissue collagenase activity, hypoxia and inflammation compared to healthy samples.

Hypoxia and collagen crosslinking in the healthy and affected sites of periodontitis patients

Present study suggests that diseased sites of periodontitis with stage 3 grade B and C had decreased fibroblast cell density, hypoxia-inducible factor (HIF) and vascular endothelial growth factor (VEGF) expressions while increased inflammatory cell counts compared to both healthy sites of the periodontitis patients and healthy controls. Collagen maturation enzymes also decreased in the diseased sites. Objective: The present study aimed at determining markers of hypoxia and collagen crosslinking in healthy and diseased gingiva from healthy individuals and periodontitis patients. Methods: Group-1; healthy individuals, Group-2; healthy sites of periodontitis patients-stage 3 grade B, (H-GradeB) Group-3; diseased sites of periodontitis patients-stage 3 grade B, (D-GradeB). Group-4; healthy sites of periodontitis patients-stage 3 grade C, (H-GradeC). Group-5; diseased sites of periodontitis patients-stage 3 grade C, (D-GradeC). Plaque index (PI), gingival index (GI) and clinical attachment levels (CALs) were recorded. Gingival biopsies were obtained. Fibroblast and inflammatory cells were counted. HIF-1α, prolyl hydroxylase (PH), VEGF, lysyl oxidase (LOX) and lysyl hydroxylase (LH) levels were determined via immunohistochemistry. Results: Fibroblast cell counts were lower in D-GradeC and D-GradeB than other groups. C group had highest fibroblast cell counts. Inflammatory cell counts were highest in the D-GradeC and lowest in C group. HIF-1α levels were highest in C group and decreased in diseased sites. Lowest value was observed in D-GradeC group. VEGF, PH, and LH levels were higher in the control group compared to other groups. LOX levels were similar in the groups except for D-GradeC. LOX levels were similar in the groups except for D-GradeC which is significantly lower than those of the control group and healthy sites. Conclusions: The results revealed that diseased sites of periodontitis patients had decreased fibroblast cells, HIF and VEGF expressions while increased inflammatory cells. Collagen crosslinking tend to decrease with disease regardless of stage and grade of disease.