Hypoxia-induced Inflammation Research Articles

Oxygen Glucose Deprivation-Induced Lactylation of H3K9 Contributes to M1 Polarization and Inflammation of Microglia Through TNF Pathway.

Hypoxia-induced M1 polarization of microglia and resultant inflammation take part in the damage caused by hypoxic-ischemic encephalopathy (HIE). Histone lactylation, a novel epigenetic modification where lactate is added to lysine residues, may play a role in HIE pathogenesis. This study investigates the role of histone lactylation in hypoxia-induced M1 microglial polarization and inflammation, aiming to provide insights for HIE treatment. In this study, we assessed the effects of hypoxia on microglial polarization using both an HIE animal model and an oxygen-glucose deprivation cell model. Histone lactylation at various lysine residues was detected by Western blotting. Microglial polarization and inflammatory cytokines were analyzed by immunofluorescence, qPCR, and Western blotting. RNA sequencing, ChIP-qPCR, and siRNA were used to elucidate mechanisms of H3K9 lactylation. H3K9 lactylation increased due to cytoplasmic lactate during M1 polarization. Inhibiting P300 or reducing lactate dehydrogenase A expression decreased H3K9 lactylation, suppressing M1 polarization. Transcriptomic analysis indicated that H3K9 lactylation regulated M1 polarization via the TNF signaling pathway. ChIP-qPCR confirmed H3K9 lactylation enrichment at the TNFα locus, promoting OGD-induced M1 polarization and inflammation. H3K9 lactylation promotes M1 polarization and inflammation via the TNF pathway, identifying it as a potential therapeutic target for neonatal HIE.

Mesenchymal stem cell-derived exosomal mir-21-5p inhibits YAP1 expression and improves outcomes in myocardial infarction

BackgroundMyocardial infarction (MI) remains a significant global health concern, characterized by cardiomyocyte apoptosis and adverse ventricular remodeling. Nevertheless, the interplay between exosomal miR-21-5p and Yes-associated protein 1 (YAP1) in the context of MI remains unexplored.MethodsRat mesenchymal stem cells (MSCs) and H9c2 cardiomyocytes were cultured, characterized, and instrumental in our experiments. Exosomes were meticulously isolated, and their identity confirmed. The internalization of these exosomes by H9c2 cells was assessed, while RNA and protein expression were quantified using Quantitative Real-Time PCR and Western blot, respectively. MTT assay was implemented for cell viability, and apoptosis was evaluated via flow cytometric analysis. To elucidate gene interactions, we conducted microarray profiling of miRNA expression, dual luciferase reporter assays, and RNA Immunoprecipitation.ResultsMSC-derived exosomes exhibited a remarkable capacity to attenuate hypoxia-induced inflammation and apoptosis in H9c2 cells. Notably, these exosomes significantly upregulated miR-21-5p levels within H9c2 cells, and the abrogation of miR-21-5p function abated their protective effects. Through computational analysis, we unveiled a miR-21-5p binding site in the 3’UTR of YAP1, which directly inhibited YAP1 expression. Importantly, the inhibition of YAP1 effectively reinstated the protective effects of exosomes in cells with impaired exosomal miR-21-5p.ConclusionThis study underscores the pivotal role played by MSC-derived exosomes in safeguarding against MI, primarily by mediating the transfer of miR-21-5p, which targets YAP1 signaling pathways.Clinical trial numberN/A.

Hypoxia-Induced Inflammation in In Vitro Model of Human Blood-Brain Barrier: Modulatory Effects of the Olfactory Ensheathing Cell-Conditioned Medium.

Hypoxia compromises the integrity of the blood-brain barrier (BBB) and increases its permeability, thereby inducing inflammation. Olfactory ensheathing cells (OECs) garnered considerable interest due to their neuroregenerative and anti-inflammatory properties. Here, we aimed to investigate the potential modulatory effects of OEC-conditioned medium (OEC-CM) on the response of human brain microvascular endothelial cells (HBMECs), constituting the BBB, when exposed to hypoxia. HBMECs were utilized to establish the in vitro BBB model. OECs were isolated from mouse olfactory bulbs, and OEC-CM was collected after 48h of culture. The effect of OEC-CM treatment on the HBMEC viability was evaluated under both normoxic and hypoxic conditions at 6h, 24h, and 30h. Western blot and immunostaining techniques were employed to assess NF-κB/phospho-NF-κB expression. HIF-1α, VEGF-A, and cPLA2 mRNA expression levels were quantified using digital PCR. ELISA assays were performed to measure PGE2, VEGF-A, IL-8 secretion, and cPLA2 specific activity. The in vitro formation of HBMEC capillary-like structures was examined using a three-dimensional matrix system. OEC-CM attenuated pro-inflammatory responses and mitigated the HIF-1α/VEGFA signaling pathway activation in HBMECs under hypoxic condition. Hypoxia-induced damage of the BBB can be mitigated by novel therapeutic strategies harnessing OEC potential.

Pre-treatment with notoginsenoside R1 from Panax notoginseng protects against high-altitude-induced pulmonary edema by inhibiting pyroptosis through the NLRP3/caspase-1/GSDMD pathway

High-altitude pulmonary edema (HAPE) is a potentially fatal condition that occurs when exposed to high-altitude hypoxia environments. Currently, there is no effective treatment for HAPE, and available interventions focus on providing relief. Notoginsenoside R1 (NGR1), a major active constituent of Panax notoginseng (Burkill) F.H.Chen (sānqī), has demonstrated heart and lung-protective effects under hypobaric hypoxia. However, there is a lack of clarity regarding the precise mechanisms that underlie the protective effects of NGR1 against inflammation. In this study, a rat model of HAPE was developed to assess the effect of NGR1 on this pathology. High-altitude hypoxia corresponding to 6000 m altitude was simulated with a hypobaric chamber. We found that NGR1 dose-dependently alleviated pulmonary oxidative stress damage and inflammatory response, and prevented acid-base balance disruption. In addition, NGR1 restored the expression levels of hypoxia-inducible factor-1 alpha, vascular endothelial growth factor, and aquaporin protein-5, correlated with the development of pulmonary edema induced by hypobaric hypoxia. Furthermore, NGR1 pre-treatment remarkably mitigated NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-induced pyroptosis, and this effect was partially counteracted by the use of an NLRP3 agonist. Thus, NGR1 may exert a lung-protective effect against HAPE by ameliorating hypoxia-induced lung edema, oxidative damage, and inflammation through inhibition of the NLRP3/Caspase-1/ GSDMD signaling pathway.

Alveolar hypoxia induces organ-specific inflammasome-related inflammation in male mouse lungs.

Inflammation through activation of caspase-1, seems to play a role in pulmonary hypertension induced by alveolar hypoxia. Whether alveolar hypoxia induces caspase-1-mediated inflammation and influx of leukocytes in other organs than the lungs, is not known. Our aim was to explore sites of caspase-1-related inflammation in alveolar hypoxia. Wild type (WT) mice were exposed to environmental hypoxia or room-air, and organs were analyzed. Right heart catheterization was performed after 14 days of alveolar hypoxia in WT mice and mice transplanted with WT or caspase-1-/- bone marrow. Hypoxia induced leukocyte accumulation and increased caspase-1 protein in the lungs, not in other organs. WT mice transplanted with WT or caspase-1-/- bone marrow showed no difference in pulmonary leukocyte accumulation or development of pulmonary hypertension after alveolar hypoxia. Caspase-1 and IL-18 were detected in bronchial epithelium in WT mice, and hypoxia induced IL-18 secretion from bronchial epithelial cells. IL-18 stimulation generated IL-6 mRNA in monocytes. Phosphorylated STAT3 was increased in hypoxic lungs, not in other organs. Alveolar hypoxia induces caspase-1 activation and leukocyte accumulation specific to the lungs, not in other organs. Caspase-1 activation and IL-18 secretion from bronchial epithelial cells might initiate hypoxia-induced inflammation, leading to pulmonary hypertension.

Development of CRID3-Based Anti-inflammatory Agents to Ameliorate Chronic Hypoxia-Induced Memory Impairment in Zebrafish Models.

Chronic hypoxic exposure triggers the onset and progression of cognitive dysfunction; however, the mechanisms underlying chronic hypoxia-induced neuroinflammation and its contribution to cognitive dysfunction remain poorly understood. Although inflammation and hypoxia are interdependent, numerous recent studies have linked the development of various human diseases to hypoxia-induced inflammation. In this study, we focused on the NLRP3 inflammasome with novel analogues of cytokine release inhibitory drug 3 (CRID3), a class of small molecule inhibitors for the NLRP3 inflammasome, to investigate their potential contribution to alleviating chronic hypoxia-induced neuroinflammation using the zebrafish model. The designed CRID3 analogues 6a-q were prepared from 2-methyl furan-3-carboxylate, following a four-step reaction sequence and fully characterized by NMR and mass spectral analysis. The administration of CRID3 analogues 6a-q led to a notable reduction in neuroinflammation and an increase in glial proliferation markers in both sexes. In addition, we investigated the potential effects of CRID3 analogues 6a-q through various behavioral tasks to assess their role in ameliorating post-hypoxic behavioral deficits and cognitive impairment. Notably, the study revealed that post-chronic hypoxia, male zebrafish exhibited significantly higher levels of inflammatory marker expression than females. Furthermore, we observed that the neurogenic response to treatment with CRID3 derivative 6o varied depending on the sex, with females showing a sex-specific differential increase in neurogenesis compared to males. This work emphasizes the significance of considering sex differences into account in developing therapeutic strategies for neurological disorders, as shown by the sex-specific molecular and behavioral changes in zebrafish cognitive impairment and neuroinflammation.

Altitude illnesses.

Millions of people visit high-altitude regions annually and more than 80 million live permanently above 2,500 m. Acute high-altitude exposure can trigger high-altitude illnesses (HAIs), including acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Chronic mountain sickness (CMS) can affect high-altitude resident populations worldwide. The prevalence of acute HAIs varies according to acclimatization status, rate of ascent and individual susceptibility. AMS, characterized by headache, nausea, dizziness and fatigue, is usually benign and self-limiting, and has been linked to hypoxia-induced cerebral blood volume increases, inflammation and related trigeminovascular system activation. Disruption of the blood-brain barrier leads to HACE, characterized by altered mental status and ataxia, and increased pulmonary capillary pressure, and related stress failure induces HAPE, characterized by dyspnoea, cough and exercise intolerance. Both conditions are progressive and life-threatening, requiring immediate medical intervention. Treatment includes supplemental oxygen and descent with appropriate pharmacological therapy. Preventive measures include slow ascent, pre-acclimatization and, in some instances, medications. CMS is characterized by excessive erythrocytosis and related clinical symptoms. In severe CMS, temporary or permanent relocation to low altitude is recommended. Future research should focus on more objective diagnostic tools to enable prompt treatment, improved identification of individual susceptibilities and effective acclimatization and prevention options.

Hypoxia-inducible factor prolyl hydroxylase inhibitor alleviates heatstroke-induced acute kidney injury by activating BNIP3-mediated mitophagy.

Hypoxia-induced inflammation and apoptosis are important pathophysiological features of heat stroke-induced acute kidney injury (HS-AKI). Hypoxia-inducible factor (HIF) is a key protein that regulates cell adaptation to hypoxia. HIF-prolyl hydroxylase inhibitor (HIF-PHI) stabilizes HIF to increase cell adaptation to hypoxia. Herein, we reported that HIF-PHI pretreatment significantly improved renal function, enhanced thermotolerance, and increased the survival rate of mice in the context of HS. Moreover, HIF-PHI could alleviate HS-induced mitochondrial damage, inflammation, and apoptosis in renal tubular epithelial cells (RTECs) by enhancing mitophagy invitro and invivo. By contrast, mitophagy inhibitors Mdivi-1, 3-MA, and Baf-A1 reversed the renoprotective effects of HIF-PHI. Mechanistically, HIF-PHI protects RTECs from inflammation and apoptosis by enhancing Bcl-2 adenovirus E18 19-kDa-interacting protein 3 (BNIP3)-mediated mitophagy, while genetic ablation of BNIP3 attenuated HIF-PHI-induced mitophagy and abolished HIF-PHI-mediated renal protection. Thus, our results indicated that HIF-PHI protects renal function by upregulating BNIP3-mediated mitophagy to improve HS-induced inflammation and apoptosis of RTECs, suggesting HIF-PHI as a promising therapeutic agent to treat HS-AKI.

Reoxygenation Mitigates Intermittent Hypoxia-Induced Systemic Inflammation and Gut Microbiota Dysbiosis in High-Fat Diet-Induced Obese Rats.

Obstructive sleep apnea (OSA) is a prevalent sleep breathing disorder characterized by intermittent hypoxia (IH), with continuous positive airway pressure (CPAP) as its standard treatment. However, the effects of intermittent hypoxia/reoxygenation (IH/R) on weight regulation in obesity and its underlying mechanism remain unclear. Gut microbiota has gained attention for its strong association with various diseases. This study aims to explore the combined influence of IH and obesity on gut microbiota and to investigate the impact of reoxygenation on IH-induced alterations. Diet-induced obese (DIO) rats were created by 8-week high-fat diet (HFD) feeding and randomly assigned into three groups (n=15 per group): normoxia (NM), IH (6% O2, 30 cycles/h, 8 h/day, 4 weeks), or hypoxia/reoxygenation (HR, 2-week IH followed by 2-week reoxygenation) management. After modeling and exposure, body weight and biochemical indicators were measured, and fecal samples were collected for 16S rRNA sequencing. DIO rats in the IH group showed increased weight gain (p=0.0016) and elevated systemic inflammation, including IL-6 (p=0.0070) and leptin (p=0.0004). Moreover, IH rats exhibited greater microbial diversity (p<0.0167), and significant alterations in the microbial structure (p=0.014), notably the order Clostridiales, accompanied by an upregulation of bile acid metabolism predicted pathway (p=0.0043). Reoxygenation not only improved IH-exacerbated obesity, systemic inflammation, leptin resistance, and sympathetic activation, but also showed the potential to restore IH-induced microbial alterations. Elevated leptin levels were associated with Ruminococcaceae (p=0.0008) and Clostridiales (p=0.0019), while body weight was linked to Blautia producta (p=0.0377). Additionally, the abundance of Lactobacillus was negatively correlated with leptin levels (p=0.0006) and weight (p=0.0339). IH leads to gut dysbiosis and metabolic disorders, while reoxygenation therapy demonstrates a potentially protective effect by restoring gut homeostasis and mitigating inflammation. It highlights the potential benefits of CPAP in reducing metabolic risk among obese patients with OSA.

16α-OHE1 alleviates hypoxia-induced inflammation and myocardial damage via the activation of β2-Adrenergic receptor

ObjectiveMyocardial injuries resulting from hypoxia are a significant concern, and this study aimed to explore potential protective strategies against such damage. Specifically, we sought to investigate the cardioprotective effects of 16α-hydroxyestrone (16α-OHE1). MethodsMale Sprague‒Dawley (SD) rats were subjected to hypoxic conditions simulating high-altitude exposure at 6000 m in a low-pressure chamber for 7 days. Before and during hypoxic exposure, estradiol (E2) and various doses of 16α-OHE1 were administered for 14 days. Heart weight/body weight (HW/BW), myocardial structure, Myocardial injury indicators and inflammatory infiltration in rats were measured. H9C2 cells cultured under 5% O2 conditions received E2 and varying doses of 16α-OHE1; Cell viability, apoptosis, inflammatory infiltration, and Myocardial injury indicators were determined. Expression levels of β2AR were determined in rat hearts and H9C2 cells. The β2AR inhibitor, ICI 118,551, was employed to investigate β2AR's role in 16α-OHE1's cardioprotective effects. ResultsHypoxia led to substantial myocardial damage, evident in increased heart HW, CK-MB, cTnT, ANP, BNP, structural myocardial changes, inflammatory infiltration, and apoptosis. Pre-treatment with E2 and 16α-OHE1 significantly mitigated these adverse changes. Importantly, the protective effects of E2 and 16α-OHE1 were associated with the upregulation of β2AR expression in both rat hearts and H9C2 cells. However, inhibition of β2AR by ICI 118,551 in H9C2 cells nullified the protective effect of 16α-OHE1 on myocardium. ConclusionOur findings suggest that 16α-OHE1 can effectively reduce hypoxia-induced myocardial injury in rats through β2ARs, indicating a promising avenue for cardioprotection.

Ginsenoside Rg1 alleviates vascular remodeling in hypoxia-induced pulmonary hypertension mice through the calpain-1/STAT3 signaling pathway

BackgroundHypoxic pulmonary hypertension (HPH) is the main pathological change in vascular remodeling, a complex cardiopulmonary disease caused by hypoxia. Some research results have shown that ginsenoside Rg1 (Rg1) can improve vascular remodeling, but the effect and mechanism of Rg1 on hypoxia-induced pulmonary hypertension are not clear. The purpose of this study was to discuss the potential mechanism of action of Rg1 on HPH. MethodsC57BL/6 mice, calpain-1 knockout mice and Pulmonary artery smooth muscle cells (PASMCs) were exposed to a low oxygen environment with or without different treatments. The effect of Rg1 and calpain-1 silencing on inflammation, fibrosis, proliferation and the protein expression levels of calpain-1, STAT3 and p-STAT3 were determined at the animal and cellular levels. ResultsAt the mouse and cellular levels, hypoxia promotes inflammation, fibrosis, and cell proliferation, and the expression of calpain-1 and p-STAT3 is also increased. Ginsenoside Rg1 administration and calpain-1 knockdown, MDL-28170, and HY-13818 treatment showed protective effects on hypoxia-induced inflammation, fibrosis, and cell proliferation, which may be associated with the downregulation of calpain-1 and p-STAT3 expression in mice and cells. In addition, overexpression of calpain 1 increased p-STAT3 expression, accelerating the onset of inflammation, fibrosis and cell proliferation in hypoxic PASMCs. ConclusionGinsenoside Rg1 may ameliorate hypoxia-induced pulmonary vascular remodeling by suppressing the calpain-1/STAT3 signaling pathway.

IMMUNOMODULATORY POTENTIAL OF MAGNETICALLY ASSISTED CELL SHEET UNDER HYPOXIC ENVIRONMENTS UPON MAGNETIC STIMULATION

Common tendon injuries impair healing, leading to debilitation and an increased re-rupture risk. The impact of oxygen-sensing pathways on repair mechanisms, vital in regulating inflammation and fibrosis, remains unclear despite their relevance in tendon pathologies. Recent studies show that pulsed electromagnetic field (PEMF) reduce inflammation in human tendon cells (hTDCs) and in hypoxia-induced inflammation. We investigated the hypoxia's impact (1% and 2% oxygen tension) using magnetic cell sheet constructs (IL-1β-magCSs) primed with IL-1β. IL-1β-magCSs were exposed to low OT (1h, 4h,6h) in a hypoxic chamber. To confirm the role of PEMF (5Hz, 4mT, 50% duty cycle) on hypoxia modulation, IL-1β-magCSs, previously exposed to OT, were 1h-stimulated with PEMF. Our results show a significant increase in HIF- 1a and HIF-2a expression on IL-1β-magCSs after exposure to 2%-OT at all time points, compared to 1%- OT and normoxia. TNFa, IL-6, and IL-8 expression increased after 6 hours of 1%-OT exposure. PEMF stimulation of hypoxic IL-1β-magCSs led to decreased pro-inflammatory genes and increased anti-inflammatory (IL-4,IL-10) expression compared to unstimulated magCSs. IFN-g, TNF-α, and IL-6 release increased after 6 hours, regardless of %-OT, while IL-10 levels tended to rise after PEMF stimulation at 2%-OT. Also, NFkB expression was increased on IL-1β-magCSs exposed to 4 h and 6 h of 2%-OT, suggesting a link between NFkB and the production of pro-inflammatory factors. Moreover, PEMF stimulation showed a significantly decreased NFkB level in IL-1β-magCSs.Overall, low OT enhances expression of hypoxia-associated genes and inflammatory markers in IL-1β-magCSs with the involvement of NFkB. PEMF modulates the response of magCSs, previously conditioned to hypoxia and to inflammatory triggers, favouring expression of anti-inflammatory genes and proteins, supporting PEMF impact in pro-regenerative tendon strategies.Acknowledgements: ERC CoG MagTendon(No.772817), FCT under the Scientific Employment Stimulus-2020.01157.CEECIND. Thanks to Hospital da Prelada for providing tendon tissue samples (Portugal), and TERMRES Hub (Norte-01-0145-FEDER-022190).

Myricetin attenuates hypoxia-induced inflammation in human adipocytes.

Adipose tissue hypoxia plays a crucial role in the development of chronic low-grade systemic inflammation which has been associated with the pathogenesis of obesity-related diseases. Myricetin is a natural compound present in numerous plant-based foods with presumed anti-inflammatory and beneficial health effects. The impact of this flavonoid on hypoxia-induced expression of inflammatory adipokines and hypoxia-regulated pathways is unknown so far and has been addressed in the present study. Differentiated human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were cultured with or without myricetin under normoxic and hypoxic conditions for varying time periods. The effect of hypoxia and myricetin on the expression of the investigated adipokines was measured by real-time RT-PCR. Western blot analysis was used for the detection of transcription factors involved in hypoxia-regulated pathways. Myricetin interfered in the hypoxia-induced regulation of adipokines and the underlying pathways, which are involved in transmitting the inflammatory response. It strongly repressed hypoxia-induced expression of apelin, leptin, chemerin, asprosin, and DPP-4 and HIF-1α accumulation in the nucleus was diminished. Furthermore, the activation of the key regulators in the inflammatory response NF-κB, Akt, and CREB was suppressed by myricetin under hypoxic conditions. Myricetin also decreased hypoxia-induced accumulation of the pro-tumorigenic transcription factors Snail and Slug in the nucleus. Taken together, our results indicated that myricetin regulated hypoxia-induced expression of adipokines and hypoxia-regulated pathways in human adipocytes. Our study therefore provided evidence of the anti-inflammatory effects of myricetin in hypoxia-treated human adipocytes.

Matrine alleviates hypoxia-induced inflammation and pulmonary vascular remodelling via RPS5/NF-κB signalling pathway.

Hypoxia-induced vasoconstriction and vascular remodelling are the main pathological features of hypoxic pulmonary arterial hypertension (HPAH), and inflammation is participated in the occurrence of pulmonary vascular remodelling (PVR). Matrine is an alkaloid with the effects of anti-inflammation, antifibrosis and antitumour. But, few studies have explored the role of matrine in regulating PVR, and the related mechanisms are still unknown. In this study, we found that hypoxia-induced pulmonary artery smooth muscle cells(PASMCs) proliferation and inhibited its apoptosis, reduced the expression of ribosomal protein s5 and activated the nuclear factor kappa-B (NF-κB) signalling. Matrine, sildenafil and NF-κB inhibitor Bay 11-7082 could reverse these changes and impel the cell cycle in phase S retardation, and reduced the expression of p50, p65, proliferating cell nuclear antigen (PCNA), Bcl-2. In addition, matrine could lower right ventricular systolic pressure and mean pulmonary artery pressureof rats,α-smooth muscle actinand PCNA expression in pulmonary artery media, the levels of tumor necrosis factor-α and interleuki-1β, thus improved hypoxia-induced PVR. This study indicated that matrine could alleviate inflammation and improve PVR through reversing the imbalance of proliferation and apoptosis of PASMCs, thus it had a therapeutic effect on HPAH.

Desialylation of ATG5 by sialidase (NEU1) promotes macrophages autophagy and exacerbates inflammation under hypoxia

During the process of atherosclerosis (AS), hypoxia induces plaque macrophage inflammation, promoting lipid accumulation. Autophagy is a cell homeostasis process that increases tolerance to stressors like oxidative stress and hypoxia. However, the specific mechanism by which hypoxia initiates autophagy and the inflammation of macrophages remains to be elucidated. Here, we found that hypoxia-induced macrophage inflammation was mediated by autophagy. Then, the effect of hypoxia on autophagy was investigated in terms of post-translational modifications of proteins. The results showed that desialylation of the autophagy protein ATG5 under hypoxic conditions enhanced protein stability by affecting its charge effect and promoted the formation of the ATG5-ATG12-ATG16L complex, further increasing autophagosome formation. And NEU1, a key enzyme in sialic acid metabolism, was significantly up-regulated under hypoxic conditions and was identified as an interacting protein of ATG5, affecting the sialylation of ATG5. In addition, the knockdown or inhibition of NEU1 reversed hypoxia-induced autophagy and inflammatory responses. In conclusion, our data reveal a key mechanism of autophagy regulation under hypoxia involving ATG5 sialylation and NEU1, suggesting that NEU1 may be a potential target for the prevention and treatment of atherosclerosis.

Novel HIF-1α Inhibitor AMSP-30m Mitigates the Pathogenic Cellular Behaviors of Hypoxia-Stimulated Fibroblast-Like Synoviocytes and Alleviates Collagen-Induced Arthritis in Rats via Inhibiting Sonic Hedgehog Pathway.

Synovial hypoxia-inducible factor 1α (HIF-1α) is a prospective therapeutic target for rheumatoid arthritis (RA). AMSP-30m, a novel HIF-1α inhibitor, was reported to have notable anti-arthritic effects in rats with adjuvant-induced arthritis. However, its roles in inhibiting the pathogenic behaviors of fibroblast-like synoviocytes (FLS) and the involved mechanisms remain unknown. Here, AMSP-30m inhibited proliferation and induced apoptosis in hypoxia-induced RA FLS (MH7A cell line), as evidenced by decreased cell viability, reduced Ki67-positive cells, G0/G1 phase arrest, lowered C-myc and Cyclin D1 protein levels, emergence of apoptotic nuclear fragmentation, raised apoptosis rates, and activation of caspase 3. Furthermore, AMSP-30m prevented hypoxia-induced increases in pro-inflammatory factor production, MMP-2 activity, migration index, migrated/invasive cells, and actin cytoskeletal rearrangement. In vivo, AMSP-30m alleviated the severity of rat collagen-induced arthritis (CIA). Mechanically, AMSP-30m reduced HIF-1α expression and blocked sonic hedgehog (Shh) pathway activation in hypoxia-induced MH7A cells and CIA rat synovium, as shown by declines in pathway-related proteins (Shh, Smo, and Gli-1). Particularly, the combination of Shh pathway inhibitor cyclopamine enhanced AMSP-30m's inhibitory effects on the pathogenic behaviors of hypoxia-stimulated MH7A cells, whereas the combination of Shh pathway activator SAG canceled AMSP-30m's therapeutic effects in vitro and in CIA rats, implying a close involvement of Shh pathway inhibition in its anti-arthritic effects. We likewise confirmed AMSP-30m's anti-proliferative role in hypoxia-induced primary CIA FLS. Totally, AMSP-30m suppressed hypoxia-induced proliferation, inflammation, migration, and invasion of MH7A cells and ameliorated the severity of rat CIA via inhibiting Shh signaling.

SENP1 modulates chronic intermittent hypoxia-induced inflammation of microglia and neuronal injury by inhibiting TOM1 pathway.

Chronic intermittent hypoxia (CIH) is a characteristic pathophysiological change of obstructive sleep apnea syndrome (OSAS). Inflammation of microglia induced by CIH, plays a vital role in OSAS-associated cognitive dysfunction. SUMO-specific proteases 1 (SENP1) has been implicated in tumor inflammatory microenvironment and cells migration. However, the role of SENP1 in CIH-induced neuroinflammation remains unknown. We aimed to investigate the effect of SENP1 on neuroinflammation and neuronal injury. After the preparation of SENP1 overexpression microglia and SENP1 knockout mouse, CIH microglia and mice were established using an intermittent hypoxia device. Results showed that CIH reduced the level of SENP1 and TOM1, induced the SUMOylation of TOM1, and promoted microglial migration, neuroinflammation, neuronal amyloid-beta 42 (Aβ42) deposition and apoptosis in vitro and in vivo. After SENP1 overexpression in vitro, the enhanced SUMOylation of TOM1 was inhibited; the level of TOM1 and microglial migration were enhanced; neuroinflammation, neuronal Aβ42 deposition and apoptosis were significantly reduced. However, the administration of siRNA-TOM1 suppressed microglial migration, neuroinflammation, neuronal Aβ42 deposition and apoptosis. After SENP1 knockout in vivo, the SUMOylation enhancement of TOM1 was accelerated, microglial migration was inhibited. Neuroinflammation, neuronal Aβ42 deposition and apoptosis, cognitive impairment was significantly exacerbated. Overall, the results demonstrated that SENP1 promoted microglial migration by alleviating the de-SUMOylation of TOM1, thus contributing to attenuate neuroinflammation, neuronal Aβ42 deposition and neuronal apoptosis induced by CIH.

0438 Obstructive sleep apnoea in patients with stroke verses those with refractory hypertension search for common pathogenic mechanism

Abstract Introduction Obstructive sleep apnea [OSA] is a risk factor for stroke and refractory hypertension [RH]. OSA causes disrupted sleep, intermittent hypoxia, and hypoxia-induced systemic inflammation and sympathetic activation are potential pathogenic mechanisms for the first ever stroke and refractory hypertension. The aim of the present study was to evaluate sleep quality among OSA among patients with first ever stroke, as compared to RH and to assess markers of sympathetic activation and systemic inflammation in patients with either stroke or RH. Methods All patients with stroke and RH were recruited from the Departments of Neurology and Cardiology, respectively at the All India Institute of Medical Sciences, New Delhi. All patients were interviewed for demographic details, clinical history and were scheduled for polysomnography. Fasting blood samples were collected during morning hours, to estimate biochemical markers [Norepinephrine, CRP, TNF-∞, VGEF and IL6] . CRP, TNF-alpha, and IL-6], measured by the chemiluminescence method. Nor-adrenaline and VEGF were measured using ELISA techniques. Results A total of 114 stroke patients and 56 refractory hypertension patients were included. The prevalence of OSA among stroke and RH patients was found to be 86.85 and 81% respectively. The mean number of wake after sleep onset periods (WASOs) [45±19.22 vs 29.8±11.14, p&amp;lt; 0.01]was significantly higher in patients with stroke. REM AHI [240.04±24.65 vs 33.20±22.35, p&amp;lt; 0.01] was significantly higher in patients with RH.CRP and VEGF values were higher than normal, in both groups. The median value of early morning serum nor-adrenaline was higher in the RH group[407 (66.6-1000) vs 515 (240-1250), p = 0.05]. Conclusion OSA is highly prevalent among the patients in both groups. Systemic inflammation is a common pathogenic mechanism linking OSA with RH and stroke, whereas early morning sympathetic activation appears significantly important in the pathogenesis of refractory hypertension. Support (if any) This study was funded by Indian council of Medical Research, New Delhi, India.

Ginsenoside Rg1 ameliorates hypoxia-induced pulmonary arterial hypertension by inhibiting endothelial-to-mesenchymal transition and inflammation by regulating CCN1

Pulmonary arterial hypertension (PAH) is a chronic obstructive disease characterized by vascular remodeling. Studies have confirmed that ginsenoside Rg1 can improve pulmonary hypertension to a certain extent, but the potential mechanism by which it improves hypoxia-induced PAH remains unclear. The aim of this study was to investigate the therapeutic effect of ginsenoside Rg1 on hypoxia-induced PAH. The results showed that hypoxia promoted inflammation, EndMT, and vascular remodeling, which were accompanied by decreased CCN1 levels and increased p-NFκB p65, TGF-β1, and p-Smad 2/3 levels. Treatment with ginsenoside Rg1, recombinant CCN1, BAY-11-7082, and SB-431542 could prevent hypoxia-induced vascular remodeling, reduce the expression of the hypoxia-induced inflammatory cytokines TNF-α and IL-1β, inhibit the expression of the mesenchymal markers α-SMA and Vimentin and restore the expression of the endothelial markers CD31 and VE-cadherin to improve hypoxia-induced EndMT, which may be associated with the upregulation of CCN1 protein expression and downregulation of p-NFκB p65, TGF-β1, and p-Smad 2/3 in rats and cells. siRNA CCN1 transfection increased the expression of p-NFκB p65, TGF-β1, and p-Smad 2/3 and accelerated the occurrence and development of inflammation and EndMT after hypoxia. In summary, our study indicated that hypoxia-induced EndMT and inflammation play a role in hypoxic pulmonary hypertension (HPH). Ginsenoside Rg1 treatment could reverse hypoxia-induced EndMT and inflammation by regulating CCN1 and has potential value in the prevention and treatment of HPH.

Exosomal miR-663b from "M1" macrophages promotes pulmonary artery vascular smooth muscle cell dysfunction through inhibiting the AMPK/Sirt1 axis.

Inflammatory mediators from macrophages are proven to be involved in pulmonary vascular remodeling in pulmonary hypertension (PH). Here, this study intends to explore the mechanism of "M1" macrophage-derived exosomal miR-663b in pulmonary artery smooth muscle cells (PASMCs) dysfunctions and pulmonary hypertension. Hypoxia-treated PASMCs were utilized for constructing an in-vitro pulmonary hypertension model. THP-1 cells were treated with PMA (320 nM) and LPS (10 μg/mL) + IFN-γ (20 ng/ml) for eliciting macrophage "M1" polarization. Exosomes derived from "M1" macrophages were isolated and added into PASMCs. The proliferation, inflammation, oxidative stress, and migration of PASMCs were evaluated. RT-PCR or Western blot examined the levels of miR-663b and the AMPK/Sirt1 pathway. Dual luciferase activity assay and RNA pull-down assay were carried out for confirming the targeted association between miR-663b and AMPK. An in-vivo PH model was built. Macrophage-derived exosomes with miR-663b inhibition were used for treating the rats, and alterations of pulmonary histopathology were monitored. miR-663b was obviously up-regulated in hypoxia-elicited PASMCs and M1 macrophages. miR-663b overexpression boosted hypoxia-induced proliferation, inflammation, oxidative stress, and migration in PASMCs, whereas miR-663b low expression resulted in the opposite situation. AMPK was identified as a target of miR-663b, and miR-663b overexpression curbed the AMPK/Sirt1 pathway. AMPK activation ameliorated the damaging impact of miR-663b overexpression and "M1" macrophage exosomes on PASMCs. In vivo, "M1" macrophage exosomes with miR-663b low expression alleviated pulmonary vascular remodeling in pulmonary hypertension rats. Exosomal miR-663b from "M1" macrophage facilitates PASMC dysfunctions and PH development by dampening the AMPK/Sirt1 axis.