BDNF corrects NLRP3 inflammasome-induced pyroptosis and glucose metabolism reprogramming through KLF2/HK1 pathway in vascular endothelial cells

A review on NLRP3 inflammasome modulation by animal venom proteins/peptides: mechanisms and therapeutic insights

The venom peptides from terrestrial as well as aquatic species have demonstrated potential in regulating the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a sophisticated assemblage present in immune cells responsible for detecting and responding to external mediators. The NLRP3 inflammasome plays a role in several pathological conditions such as type 2 diabetes, hyperglycemia, Alzheimer's disease, obesity, autoimmune disorders, and cardiovascular disorders. Venom peptides derived from animal venoms have been discovered to selectively induce certain signalling pathways, such as the NLRP3 inflammasome, mitogen-activated protein kinase (MAPK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Experimental evidence has demonstrated that venom peptides can regulate the expression and activation of the NLRP3 inflammasome, resulting in the secretion of pro-inflammatory cytokines including interleukin (IL)-1β and IL-18. Furthermore, these peptides have been discovered to impede the activation of the NLRP3 inflammasome, therefore diminishing inflammation and tissue injury. The functional properties of venom proteins and peptides obtained from snakes, bees, wasps, and scorpions have been thoroughly investigated, specifically targeting the NLRP3 inflammasome pathway, venom proteins and peptides have shown promise as therapeutic agents for the treatment of certain inflammatory disorders. This review discusses the pathophysiology of NLRP3 inflammasome in the onset of various diseases, role of venom as therapeutics. Further, various venom components and their role in the modulation of NLRP3 inflammasome are discoursed. A substantial number of venomous animals and their toxins are yet unexplored, and to comprehensively grasp the mechanisms of action of them and their potential as therapeutic agents, additional research is required which can lead to the development of novel therapeutics.

CircFndc3b Mediates Exercise-Induced Neuroprotection by Mitigating Microglial/Macrophage Pyroptosis via the ENO1/KLF2 Axis in Stroke Mice

Circular RNA (circRNA) plays a pivotal role in regulating neurological damage post-ischemic stroke. Previous researches demonstrated that exercise mitigates neurological dysfunction after ischemic stroke, yet the specific contributions of circRNAs to exercise-induced neuroprotection remain unclear. This study reveals that mmu_circ_0001113 (circFndc3b) is markedly downregulated in the penumbral cortex of a mouse model subjected to middle cerebral artery occlusion (MCAO). However, exercise increased circFndc3b expression in microglia/macrophages, alleviating pyroptosis, reducing infarct volume, and enhancing neurological recovery in MCAO mice. Mechanistically, circFndc3b interacted with Enolase 1 (ENO1), facilitating ENO1's binding to the 3' Untranslated Region (3'UTR) of Krüppel-like Factor 2 (Klf2) mRNA, thereby stabilizing Klf2 mRNA and increasing its protein expression, which suppressed NOD-like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome-mediated microglial/macrophage pyroptosis. Additionally, circFndc3b enhanced ENO1's interaction with the 3'UTR of Fused in Sarcoma (FUS) mRNA, leading to increased FUS protein levels and promoting circFndc3b cyclization. These results suggest that circFndc3b mediates exercise-induced anti-pyroptotic effects via the ENO1/Klf2 axis, and a circFndc3b/ENO1/FUS positive feedback loop may potentiate exercise's neuroprotective effects. This study unveils a novel mechanism underlying exercise-induced neuroprotection in ischemic stroke and positions circFndc3b as a promising therapeutic target for stroke management, mimicking the beneficial effects of exercise.

ANRIL's Epigenetic Regulation and Its Implications for Cardiovascular Disorders

Cardiovascular disorders (CVDs) are a major global health concern, but their underlying molecular mechanisms are not fully understood. Recent research highlights the role of long noncoding RNAs (lncRNAs), particularly ANRIL, in cardiovascular development and disease. ANRIL, located in the human genome's 9p21 region, significantly regulates cardiovascular pathogenesis. It controls nearby tumor suppressor genes CDKN2A/B through epigenetic pathways, influencing cell growth and senescence. ANRIL interacts with epigenetic modifiers, leading to altered histone modifications and gene expression changes. It also acts as a transcriptional regulator, impacting key genes in CVD development. ANRIL's involvement in cardiovascular epigenetic regulation suggests potential therapeutic strategies. Manipulating ANRIL and its associated epigenetic modifiers could offer new approaches to managing CVDs and preventing their progression. Dysregulation of ANRIL has been linked to various cardiovascular conditions, including coronary artery disease, atherosclerosis, ischemic stroke, and myocardial infarction. This abstract provides insights from recent research, emphasizing ANRIL's significance in the epigenetic landscape of cardiovascular disorders. By shedding light on ANRIL's role in cellular processes and disease development, the abstract highlights its potential as a therapeutic target for addressing CVDs.

Treponema Pallidum protein Tp47 triggers macrophage inflammatory senescence via PKM2-mediated metabolic reprogramming

Syphilis is a sexually transmitted disease caused by Treponema pallidum. The mechanisms enabling T. pallidum to persist despite macrophage eradication efforts in syphilis remain unclear. Pathogens can exploit senescent cells to enhance host susceptibility, and cellular senescence can be induced by pyroptosis, which known as inflammatory senescence. While recent studies have linked metabolic reprogramming to inflammatory senescence, their role in syphilis remained to be clarified. This study investigated the mechanisms of Tp47 on metabolic reprogramming and inflammatory senescence in macrophages. The results demonstrated that Tp47 triggered NLRP3 inflammasome-mediated pyroptosis by activating the phosphorylation of EIF2AK2 (a protein kinase), increasing senescence-associated pro-inflammatory cytokines secretion and leading to inflammatory senescence in macrophages. Additionally, Tp47 competitively bound to pyruvate kinase M2 (PKM2) with STUB1(a ubiquitin ligase), thereby inhibiting PKM2 ubiquitination degradation. By promoting the Y105 phosphorylation of PKM2, Tp47 modulated the intracellular function of PKM2, and facilitated PKM2-mediated metabolic reprogramming, which produced lactate that subsequently led to EIF2AK2 phosphorylation. Furthermore, inhibitors targeting EIF2AK2, lactate, glycolysis, and PKM2 effectively suppressed the inflammatory senescence induced by Tp47. In conclusion, Tp47 could mediate immune metabolic reprogramming through interaction with PKM2 to trigger macrophage inflammatory senescence. These discoveries offer a novel perspective for targeted therapies against syphilis.

Pathophysiological role and potential drug target of NLRP3 inflammasome in the metabolic disorders

NLRP3 plays a role in the development of autoinflammatory diseases. NLRP3, ASC, and Caspases 1 or 8 make up the NLRP3 inflammasome, which is an important part of innate immune system. The NLRP3 inflammasome-mediated inflammatory cytokines may also participate in metabolic disorders, such as diabetes, hyperlipidemia, atherosclerosis, non-alcoholic fatty liver disease, and gout. Hence, an overview of the NLRP3 regulation in these metabolic diseases and the potential drugs targeting NLRP3 is the focus of this review.

Exploring the role of traditional Chinese medicine rehabilitation in stroke based on microRNA-mediated pyroptosis: A review

Stroke, also known as "cerebrovascular accident," is a disease caused by acute impairment of brain circulation, which has a high rate of disability and mortality. Ischemic stroke (IS) is the most common type of stroke and a major cause of death and disability worldwide. At present, there are still many limitations in the treatment of IS, so it may be urgent to explore more treatments for IS. In recent years, the clinical application of traditional Chinese medicine rehabilitation methods such as traditional Chinese medicine, acupuncture, massage, traditional exercises and modern rehabilitation technology has achieved good results in the treatment of IS. Concurrently, studies have identified microRNA (miRNA), which are intimately associated with traditional Chinese medicine rehabilitation, as regulators of pyroptosis through their influence on microglia activity, inflammatory response, oxidative stress, angiogenesis and other factors, but at present, the mechanism of this direction has not been systematically summarized. Consequently, this article delineates in detail the specific role of miRNA in IS and the related activation pathways of pyroptosis in IS. This article presents a detailed discussion of the role of microRNA-mediated pyroptosis in IS, with a particular focus on the signaling pathways involved. The aim is to provide new insights for the research of traditional Chinese medicine (TCM) rehabilitation in the prevention and treatment of IS. In addition, the article explores the potential of TCM rehabilitation in regulating miRNA-mediated pyroptosis to intervene in IS.

Myokines: A central point in managing redox homeostasis and quality of life

Redox homeostasis is a crucial phenomenon that is obligatory for maintaining the healthy status of cells. However, the loss of redox homeostasis may lead to numerous diseases that ultimately result in a compromised quality of life. Skeletal muscle is an endocrine organ that secretes hundreds of myokines. Myokines are peptides and cytokines produced and released by muscle fibers. Skeletal muscle secreted myokines act as a robust modulator for regulating cellular metabolism and redox homeostasis which play a prime role in managing and improving metabolic function in multiple organs. Further, the secretory myokines maintain redox homeostasis not only in muscles but also in other organs of the body via stabilizing oxidants and antioxidant levels. Myokines are also engaged in maintaining mitochondrial dynamics as mitochondria is a central point for the generation of reactive oxygen species (ROS). Ergo, myokines also act as a central player in communicating signals to other organs, including the pancreas, gut, liver, bone, adipose tissue, brain, and skin via their autocrine, paracrine, or endocrine effects. The present review provides a comprehensive overview of skeletal muscle-secreted myokines in managing redox homeostasis and quality of life. Additionally, probable strategies will be discussed that provide a solution for a better quality of life.

The predictive value of mBDNF for major adverse cardiovascular events in stable coronary artery disease patients with depressive symptoms: A single-center, 5-year follow-up study

BACKGROUND

Myokines play vital roles in both stable coronary artery disease (SCAD) and depression. Meanwhile, there is a pressing necessity to find effective biomarkers for early predictor of major adverse cardiovascular events (MACE) in SCAD patients with depressive symptoms.

METHODS

A single-center, 5-year follow-up study was investigated. MACE was defined as composite end points, including cardiovascular death, non-fatal stroke, non-fatal myocardial infarction, coronary artery revascularization, or hospitalization for unstable angina.

RESULTS

A total of 116 SCAD patients were enrolled, consisting of 30 cases (25.9%) without depressive symptoms and 86 cases (74.1%) with depressive symptoms. During the follow-up, 3 patients (2.6%) were lost. Out of 113 patients, 51 (45.1%) experienced MACE. In the subgroup of 84 SCAD patients with depressive symptoms, 44 cases (52.4%) of MACE were observed. Finally, mature brain-derived neurotrophic factor (mBDNF), pro-brain-derived neurotrophic factor, receptor activator of nuclear factor-κB ligand, smoking history, hypertension and cystatin C were incorporated into the predictive model.

CONCLUSIONS

Depressive symptoms represent an independent risk factor for MACE in patients with SCAD. Additionally, low mBDNF expression may be an important early predictor for MACE in SCAD patients with depressive symptoms. The predictive model may exhibit a commendable predictive performance for MACE in SCAD patients with depressive symptoms.

Malus toringoides (Rehd.) Hughes decoction alleviates isoproterenol-induced cardiac fibrosis by inhibiting cardiomyocyte inflammation and pyroptosis via the HK1/NLRP3 signaling pathway

Malus toringoides (Rehd.) Hughes, called "Eseye (Ese)," is a traditional medicinal plant from the Tibet province of China that has proven effective in treating cardiac conditions due to its anti-inflammatory, antioxidative, and antiapoptotic properties. In this study, we explored the underlying protective mechanisms of Ese decoction in isoproterenol (ISO)-induced cardiac fibrosis (CF) and established the fact that treatment with an Ese decoction attenuated tissue injury, decreased the release of IL-1β, IL-18, TNF-α, and caspase-3, and elevated the Bax/Bcl-2 ratio in CF mice. We also found that with Ese treatment damage to the mitochondrial ultrastructure of myocardium was alleviated, and the level of reactive oxygen species was markedly diminished. Ese inhibited the expression of proteins associated with pyroptosis by the HK1/NLRP3 signaling pathway and also improved CF. Due to the anti-inflammatory, antioxidative, and antiapoptotic characteristics of Ese decoction, we found that Ese protected against ISO-induced CF, by inhibiting inflammation and pyroptosis as mediated by the HK1/NLRP3 signaling pathway.

Mitochondrial Dysfunction in Endothelial Progenitor Cells: Unraveling Insights from Vascular Endothelial Cells

Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.

Cichoric acid improves isoproterenol-induced myocardial fibrosis via inhibition of HK1/NLRP3 inflammasome-mediated signaling pathways by reducing oxidative stress, inflammation, and apoptosis

Cichoric acid (CA), a natural phenolic compound found in many plants, has been reported to have antioxidant, anti-inflammatory, hypoglycemic, and other effects. The aim of this study was to determine the potential role and underlying mechanisms of CA in isoproterenol (ISO)-induced myocardial fibrosis (MF). The MF model was induced by subcutaneous ISO injection in mice. Blood and heart tissue were collected for examination. Hematoxylin and eosin staining and Masson's trichrome staining were used to evaluate the histopathological changes and collagen deposition. The production of reactive oxygen species markers was observed by fluorescence microscopy, the degree of cardiomyocyte microstructure injury was observed by transmission electron microscope, and oxidative stress factors were detected by kit method, and the effect of CA on inflammatory factors was detected by ELISA. The expression levels of collagen proteins and signaling pathways were further investigated by western blotting. The results showed that CA inhibited the expression of ISO-induced proinflammatory factors (TNF-α, IL-1β, and IL-18) and proteins (HK1, NLRP3, caspase-1, cleaved-caspase-1, and ASC), and regulated the expression of apoptotic factors (caspase-3, cleaved-caspase-3, Bax, and Bcl-2). The results indicated that CA may regulate the HK1/NLRP3 inflammasome pathway by inhibiting HK1 expression and play a protective role in MF.

KLF2/PPARγ axis contributes to trauma-induced heterotopic ossification by regulating mitochondrial dysfunction

Trauma-induced heterotopic ossification (HO) is a complex disorder after musculoskeletal injury and characterized by aberrant extraskeletal bone formation. Recent studies shed light on critical role of dysregulated osteogenic differentiation in aberrant bone formation. Krupel-like factor 2 (KLF2) and peroxisome proliferator-activated receptor gamma (PPARγ) are master adapter proteins that link cellular responses to osteogenesis; however, their roles and relationships in HO remain elusive. Using a murine burn/tenotomy model in vivo, we identified elevated KLF2 and reduced PPARγ levels in tendon stem/progenitor cells (TSPCs) during trauma-induced HO formation. Both KLF2 inhibition and PPARγ promotion reduced mature HO, whereas the effects of PPARγ promotion were abolished by KLF2 overexpression. Additionally, mitochondrial dysfunction and reactive oxygen species (ROS) production also increased after burn/tenotomy, and improvements in mitochondrial function (ROS scavenger) could alleviate HO formation, but were abolished by KLF2 activation and PPARγ suppression by affecting redox balance. Furthermore, in vitro, we found increased KLF2 and decreased PPARγ levels in osteogenically induced TSPCs. Both KLF2 inhibition and PPARγ promotion relieved osteogenesis by improving mitochondrial function and maintaining redox balance, and effects of PPARγ promotion were abolished by KLF2 overexpression. Our findings suggest that KLF2/PPARγ axis exerts regulatory effects on trauma-induced HO through modulation of mitochondrial dysfunction and ROS production in TSPCs by affecting redox balance. Targeting KLF2/PPARγ axis and mitochondrial dysfunction can represent attractive approaches to therapeutic intervention in trauma-induced HO.

The Mechanism of Astragaloside IV in NOD-like Receptor Family Pyrin Domain Containing 3 Inflammasome-mediated Pyroptosis after Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is one of the most common subtypes of stroke.

OBJECTIVES

This study aimed to investigate the mechanism of Astragaloside IV (AS-IV) on inflammatory injury after ICH.

METHODS

The ICH model was established by the injection of collagenase and treated with ASIV (20 mg/kg or 40 mg/kg). The neurological function, water content of the bilateral cerebral hemisphere and cerebellum, and pathological changes in brain tissue were assessed. The levels of interleukin-1 beta (IL-1β), IL-18, tumor necrosis factor-alpha, interferon-gamma, and IL-10 were detected by enzyme-linked immunosorbent assay. The levels of Kruppel-like factor 2 (KLF2), NOD-like receptor family pyrin domain containing 3 (NLRP3), GSDMD-N, and cleaved-caspase-1 were detected by reverse transcription-quantitative polymerase chain reaction and Western blot assay. The binding relationship between KLF2 and NLRP3 was verified by chromatin-immunoprecipitation and dual-luciferase assays. KLF2 inhibition or NLRP3 overexpression was achieved in mice to observe pathological changes.

RESULTS

The decreased neurological function, increased water content, severe pathological damage, and inflammatory response were observed in mice after ICH, with increased levels of NLRP3/GSDMD-N/cleaved-caspase-1/IL-1β/IL-18 and poorly-expressed KLF2 in brain tissue. After AS-IV treatment, the neurological dysfunction, high brain water content, inflammatory response, and pyroptosis were alleviated, while KLF2 expression was increased. KLF2 bonded to the NLRP3 promoter region and inhibited its transcription. Down-regulation of KLF2 or upregulation of NLRP3 reversed the effect of AS-IV on inhibiting pyroptosis and reducing inflammatory injury in mice after ICH.

CONCLUSION

AS-IV inhibited NLRP3-mediated pyroptosis by promoting KLF2 expression and alleviated inflammatory injury in mice after ICH.

LncRNA-mediated Modulation of Endothelial Cells: Novel Progress in the Pathogenesis of Coronary Atherosclerotic Disease

Coronary atherosclerotic disease (CAD) is a common cardiovascular disease and an important cause of death. Moreover, endothelial cells (ECs) injury is an early pathophysiological feature of CAD, and long noncoding RNAs (lncRNAs) can modulate gene expression. Recent studies have shown that lncRNAs are involved in the pathogenesis of CAD, especially by regulating ECs. In this review, we summarize the novel progress of lncRNA-modulated ECs in the pathogenesis of CAD, including ECs proliferation, migration, adhesion, angiogenesis, inflammation, apoptosis, autophagy, and pyroptosis. Thus, as lncRNAs regulate ECs in CAD, lncRNAs will provide ideal and novel targets for the diagnosis and drug therapy of CAD.

The m6A Reader YTHDF1 Improves Sevoflurane-Induced Neuronal Pyroptosis and Cognitive Dysfunction Through Augmenting CREB-BDNF Signaling

Sevoflurane is one of the most widely used anesthetics in surgery which is the main cause of postoperative cognitive dysfunction (POCD). Previous reports confirmed that YTHDF1 is differently expressed in sevoflurane-induced POCD, while the roles and mechanistic details remain unclear. The molecular expressions were assessed using qRT-PCR, western blot, immunofluorescence and immunohistochemistry. Pathological change in the hippocampus tissues was analyzed using HE staining. Cognitive ability in rats was measured using MWM test. Hippocampal neuronal viability and apoptosis were measured by MTT assay and flow cytometry, respectively. The levels of pro-inflammatory cytokines were assessed using ELISA. The interaction between YTHDF1 and CREB was analyzed by RNA immunoprecipitation assay. YTHDF1 was significantly decreased in hippocampus tissues by sevoflurane exposure, and its overexpression could improve sevoflurane-induced neuron damage and cognitive dysfunction. Meanwhile, YTHDF1 upregulation repressed sevoflurane-induced activation of NLRP3 inflammation and pyroptosis in hippocampus tissues. Subsequently, YTHDF1 directly interacted to CREB mRNA to augment its stability and translation via a m6A-dependent manner, thus activating CREB/BDNF pathway. In addition, the inactivation of CREB/BDNF pathway could reverse the protective effects of YTHDF1 overexpression on sevoflurane-mediated neuronal damage and pyroptosis. These findings revealed that YTHDF1 improved sevoflurane-induced neuronal pyroptosis and cognitive dysfunction through activating CREB-BDNF signaling.

Yueliang Yin Ameliorates Endometrial Receptivity in Mice with Embryo Implantation Failure by Reducing Pyroptosis and Activating BDNF/TrkB Pathway

SCOPE

Endometrial receptivity plays a vital role in embryonic implantation. Yueliang Yin is a marketed solid drink in China, also known as Bushen Cuyun Recipe (BCR), that is, assumed to have a therapeutic effect on infertility by improving endometrial receptivity. This study investigates the effects and mechanisms of BCR in protecting the endometrium.

METHODS AND RESULTS

Mice with mifepristone-induced embryo implantation failure that exhibited a decreased implantation sites number, thinner endometrium, reduced endometrial glands number, and poor pinopode expression levels are treated with BCR, and these mentioned conditions significantly improves afterward. Molecular docking shows that the main active components kaempferol, quercetin, and hesperetin of BCR stably bound to gasdermin D (GSDMD). Experimental results demonstrate that levels of GSDMD, cleaved caspase-1 and leucine-rich repeat, and pyrin domain-containing 3 and IL-1β levels in model mice are significantly decreased and expressions of brain-derived neurotrophic factor (BDNF) and tyrosine protein kinase B (TrkB) expression levels are significantly elevated after BCR treatments, and that the DNA damage is significantly reversed in BCR-treated mice.

CONCLUSIONS

BCR is potent and effective in ameliorating endometrial receptivity. The potential mechanisms of BCR on endometrial receptivity may mediate by activating BDNF/TrkB pathway activation and protecting endometrial cells' protection against pyroptosis.

Phlorizin ameliorates myocardial fibrosis by inhibiting pyroptosis through restraining HK1-mediated NLRP3 inflammasome activation

The specific role of phlorizin (PHL), which has antioxidant, anti-inflammatory, hypoglycemic, antiarrhythmic and antiaging effects, on myocardial fibrosis (MF) and the related pharmacological mechanisms remain unknown. The objective of this study was to determine the protective actions of PHL on isoprenaline (ISO)-induced MF and its molecular mechanisms in mice. PHL was administered at 100 and 200 mg/kg for 15 consecutive days with a subcutaneous injection of ISO (10 mg/kg). MF was induced by ISO and alleviated by treatment with PHL, as shown by reduced fibrin accumulation in the myocardial interstitium and decreased levels of myocardial enzymes, such as creatinine kinase-MB, lactate dehydrogenase, and aspartate transaminase. In addition, PHL significantly decreased the expression of the fibrosis-related factors alpha smooth muscle actin, collagen I, and collagen III induced by ISO. The generation of intracellular reactive oxygen species induced by ISO was attenuated after PHL treatment. The malondialdehyde level was reduced, whereas the levels of superoxide dismutase, catalase, and glutathione were elevated with PHL administration. Moreover, compared to ISO, the level of Bcl-2 was increased and the level of Bax protein was decreased in the PHL groups. PHL relieved elevated TNF-α, IL-1β, and IL-18 levels as well as cardiac mitochondrial damage resulting from ISO. Further studies showed that PHL downregulated the high expression of hexokinase 1 (HK1), NLRP3, ASC, Caspase-1, and GSDMD-N caused by ISO. In conclusion, our findings suggest that PHL protects against ISO-induced MF due to its antioxidant, anti-apoptotic, and anti-inflammatory activities and via inhibition of pyroptosis mediated by the HK1/NLRP3 signaling pathway in vivo.

Exploring a new mechanism between lactate and VSMC calcification: PARP1/POLG/UCP2 signaling pathway and imbalance of mitochondrial homeostasis

Lactate leads to the imbalance of mitochondria homeostasis, which then promotes vascular calcification. PARP1 can upregulate osteogenic genes and accelerate vascular calcification. However, the relationship among lactate, PARP1, and mitochondrial homeostasis is unclear. The present study aimed to explore the new molecular mechanism of lactate to promote VSMC calcification by evaluating PARP1 as a breakthrough molecule. A coculture model of VECs and VSMCs was established, and the model revealed that the glycolysis ability and lactate production of VECs were significantly enhanced after incubation in DOM. Osteogenic marker expression, calcium deposition, and apoptosis in VSMCs were decreased after lactate dehydrogenase A knockdown in VECs. Mechanistically, exogenous lactate increased the overall level of PARP and PARylation in VSMCs. PARP1 knockdown inhibited Drp1-mediated mitochondrial fission and partially restored PINK1/Parkin-mediated mitophagy, thereby reducing mitochondrial oxidative stress. Moreover, lactate induced the translocation of PARP1 from the nucleus to the mitochondria, which then combined with POLG and inhibited POLG-mediated mitochondrial DNA synthesis. This process led to the downregulation of mitochondria-encoded genes, disturbance of mitochondrial respiration, and inhibition of oxidative phosphorylation. The knockdown of PARP1 could partially reverse the damage of mitochondrial gene expression and function caused by lactate. Furthermore, UCP2 was upregulated by the PARP1/POLG signal, and UCP2 knockdown inhibited Drp1-mediated mitochondrial fission and partially recovered PINK1/Parkin-mediated mitophagy. Finally, UCP2 knockdown in VSMCs alleviated DOM-caused VSMC calcification in the coculture model. The study results thus suggest that upregulated PARP1 is involved in the mechanism through which lactate accelerates VSMC calcification partly via POLG/UCP2-caused unbalanced mitochondrial homeostasis.

LINC00346 regulates NLRP1-mediated pyroptosis and autophagy via binding to microRNA-637 in vascular endothelium injury

Endothelial injury and dysfunction contributes to atherosclerosis. LINC00346 plays a key role in vascular endothelial cell injury, however, the specific mechanism remains unclear. This study intends to further explore the relationship between LINC00346 and vascular endothelial injury. Circulating LINC00346 was significantly elevated in patients with coronary artery disease and had high diagnostic value for coronary artery disease. In cell experiments, we found that LINC00346 expression was significantly increased in the oxidized low-density lipoprotein (ox-LDL) intervention group, and LINC00346 knockdown delayed ox-LDL induced human umbilical vein endothelial cell (HUVEC) endothelial-to-mesenchymal transition. In addition, knockdown of LINC00346 mitigated ox-LDL-induced NOD-like receptor protein 1 (NLRP1)-mediated inflammasome formation and pyroptosis, but had no significant effect on NLRP3. By observing the number of autophagosome and detecting intracellular autophagic flux, we found that LINC00346 knockdown inhibited the ox-LDL-induced increase in intracellular autophagy level. Dual-luciferase reporter assay, RNA immunoprecipitation assay, and RNA-pull down assay were performed to confirm the inter-molecular interaction. LINC00346 acted as microRNA-637 sponge to up-regulate the expression of NLRP1. Up-regulation of microRNA-637 alleviated NLRP1-mediated pyroptosis in HUVEC and reduced intracellular autophagosome and autolysosome formation. Finally, we explored whether pyropotosis and autophagy interact with each other. We found that inhibition of intracellular autophagy could alleviate NLRP1-mediated pyroptosis. In conclusion, LINC00346 inhibited the activation of NLRP1-mediated pyroptosis and autophagy via binding to microRNA-637, therefore mitigating vascular endothelial injury.

Pyroptosis: A Promising Mechanism Linking SARS-CoV-2 Infection to Adverse Pregnancy Outcomes

Pregnancy is characterized by a delicate immune balance; therefore, infectious diseases might increase the risk of adverse pregnancy outcomes (APOs). Here, we hypothesize that pyroptosis, a unique cell death pathway mediated by the NLRP3 inflammasome, could link SARS-CoV-2 infection, inflammation, and APOs. Two blood samples were collected from 231 pregnant women at 11-13 weeks of gestation and in the perinatal period. At each time point, SARS-CoV-2 antibodies and neutralizing antibody titers were measured by ELISA and microneutralization (MN) assays, respectively. Plasmatic NLRP3 was determined by ELISA. Fourteen miRNAs selected for their role in inflammation and/or pregnancy were quantified by qPCR and further investigated by miRNA-gene target analysis. NLRP3 levels were positively associated with nine circulating miRNAs, of which miR-195-5p was increased only in MN+ women (p-value = 0.017). Pre-eclampsia was associated with a decrease in miR-106a-5p (p-value = 0.050). miR-106a-5p (p-value = 0.026) and miR-210-3p (p-value = 0.035) were increased in women with gestational diabetes. Women giving birth to small for gestational age babies had lower miR-106a-5p and miR-21-5p (p-values = 0.001 and 0.036, respectively), and higher miR-155-5p levels (p-value = 0.008). We also observed that neutralizing antibodies and NLRP3 concentrations could affect the association between APOs and miRNAs. Our findings suggest for the first time a possible link between COVID-19, NLRP3-mediated pyroptosis, inflammation, and APOs. Circulating miRNAs might be suitable candidates to gain a comprehensive view of this complex interplay.

Glycometabolism reprogramming: Implications for cardiovascular diseases

Glycometabolism is well known for its roles as the main source of energy, which mainly includes three metabolic pathways: oxidative phosphorylation, glycolysis and pentose phosphate pathway. The orderly progress of glycometabolism is the basis for the maintenance of cardiovascular function. However, upon exposure to harmful stimuli, the intracellular glycometabolism changes or tends to shift toward another glycometabolism pathway more suitable for its own development and adaptation. This shift away from the normal glycometabolism is also known as glycometabolism reprogramming, which is commonly related to the occurrence and aggravation of cardiovascular diseases. In this review, we elucidate the physiological role of glycometabolism in the cardiovascular system and summarize the mechanisms by which glycometabolism drives cardiovascular diseases, including diabetes, cardiac hypertrophy, heart failure, atherosclerosis, and pulmonary hypertension. Collectively, directing GMR back to normal glycometabolism might provide a therapeutic strategy for the prevention and treatment of related cardiovascular diseases.

Calenduloside e modulates macrophage polarization via KLF2-regulated glycolysis, contributing to attenuates atherosclerosis

Glycolysis-mediated macrophage polarization plays a crucial role in atherosclerosis. Although it is known that calenduloside E (CE) exerts anti-inflammatory and lipid-lowering effects in atherosclerosis, the underlying mechanism of action is not clearly understood. We hypothesized that CE functions by inhibiting M1 macrophage polarization via regulation of glycolysis. To verify this hypothesis, we determined the effects of CE in apolipoprotein E deficient (ApoE^-/-) mice and on macrophage polarization in oxidized low-density lipoprotein (ox-LDL)-induced RAW 264.7 macrophages and peritoneal macrophages. We also determined whether these effects are linked to regulation of glycolysis both in vivo and in vitro. The plaque size was reduced, and serum cytokine levels were decreased in the ApoE^-/- +CE group compared with that in the model group. CE decreased lipid droplet formation, inflammatory factor levels, and mRNA levels of M1 macrophage markers in ox-ldl-induced macrophages. CE suppressed ox-ldl-induced glycolysis, lactate levels, and glucose uptake. The relationship between glycolysis and M1 macrophage polarization was demonstrated using the glycolysis inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one. CE substantially upregulated ox-ldl-induced Kruppel-like transcription factor (KLF2) expression, and the effects of CE on ox-ldl-induced glycolysis and inflammatory factor levels disappeared after KLF2 knockdown. Together, our findings suggest that CE alleviates atherosclerosis by inhibiting glycolysis-mediated M1 macrophage polarization through upregulation of KLF2 expression, providing a new strategy for the treatment of atherosclerosis.

Hydroxysafflor yellow A protects against colitis in mice by suppressing pyroptosis via inhibiting HK1/NLRP3/GSDMD and modulating gut microbiota

Hydroxysafflor yellow A (HSYA), a chalcone glycoside, is a component of Carthamus tinctorius L. and exerts anti-inflammatory and antioxidative effects. However, the therapeutic effect and the underlying mechanism of HSYA on ulcerative colitis is unclear. This study aimed to investigate the unexplored protective effects and underlying mechanisms of HSYA on UC. In vitro analyses showed that HSYA reduced the secretion of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6 and inhibited nucleotide-binding and oligomerization domain-like receptor protein 3 (NLRP3)/gasdermin D (GSDMD)-mediated pyroptosis in lipopolysaccharide/ adenosine-5'-triphosphate (LPS/ATP)-stimulated macrophages. Gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites showed that HSYA reduced the increased levels of glucose, glucose 6-phosphate, and lactic acid, and inhibited the increased hexokinase 1 (HK1) expression caused by LPS/ATP stimulation. HK1 shRNA transfection further confirmed that HSYA inhibited the NLRP3/GSDMD-mediated pyroptosis via HK1 downregulation. In vivo analyses showed that HSYA drastically attenuated UC symptoms by relieving body weight loss, a decline in colon length, and inflammatory infiltration in colonic tissues induced by dextran sulfate sodium (DSS). HSYA also reduced the secretion of pro-inflammatory cytokines including IL-1β, IL-6, TNF-α, and IL-18. Moreover, HSYA inhibited HK1/NLRP3/GSDMD-mediated pyroptosis in DSS-induced colitis mice. Finally, 16S rRNA sequencing analyses of gut microbiota revealed that HSYA reversed gut microbiota dysbiosis by reducing the abundance of Proteobacteria and increasing that of Bacteroidetes. This study demonstrated that HSYA not only exerted anti-inflammatory effects by inhibiting HK1/NLRP3/GSDMD and suppressing pyroptosis but also regulated gut microbiota in mice with DSS-induced colitis. Our findings provide new experimental evidence that HSYA might be a potential candidate for treating inflammatory bowel diseases.

NLRP3 Inflammasome in Atherosclerosis: Putting Out the Fire of Inflammation

Atherosclerosis (AS) is a chronic inflammatory disease with thickening or hardening of the arteries, which led to the built-up of plaques in the inner lining of an artery. Among all the clarified pathogenesis, the over-activation of inflammatory reaction is one of the most acknowledged one. The nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3 (NLRP3) inflammasome, as a vital and special form of inflammation and innate immunity, has been widely revealed to participate in the onset and development of AS. This review will introduce the process of the pathogenesis and progression of AS, and will describe the biological features of the NLRP3 inflammasome. Furthermore, the role of the NLRP3 inflammasome in AS and the possible mechanisms will be discussed. In addition, several kinds of agents with the effect of anti-atherosclerotic taking advantage of the NLRP3 inflammasome intervention will be described and discussed in detail, including natural compounds (baicalin, dihydromyricetin, luteolin, 5-deoxy-rutaecarpine (R3) and Salvianolic acid A, etc.), microRNAs (microRNA-30c-5p, microRNA-9, microRNA-146a-5p, microRNA-16-5p and microRNA-181a, etc.), and autophagy regulators (melatonin, dietary PUFA and arglabin, etc.). We aim to provide novel insights in the exploration of the specific mechanisms of AS and the development of new treatments of AS.

NGF and BDNF in pediatrics syndromes

Neurotrophins (NTs) as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) play multiple roles in different settings including neuronal development, function and survival in both the peripheral and the central nervous systems from early stages. This report aims to provide a summary and subsequent review of evidences on the role of NTs in rare and non-common pediatric human diseases associated with changes in neurodevelopment. A variety of diseases has been analyzed and many have been linked to NTs neurobiological effects, including chronic granulomatous disease, hereditary sensory and autonomic neuropathy, Duchenne muscular dystrophy, Bardet-Biedl syndrome, Angelman syndrome, fragile X syndrome, trisomy 16, Williams-Beuren syndrome, Prader-Willi syndrome, WAGR syndrome, fetal alcohol spectrum disorders, Down syndrome and Klinefelter Syndrome. NTs alterations have been associated with numerous pathologic manifestations including cognitive defects, behavioral abnormalities, epilepsy, obesity, tumorigenesis as well as muscle-skeletal, immunity, bowel, pain sensibility and cilia diseases. In this report, we discuss that further studies are needed to clear a possible therapeutic role of NTs in these still often uncurable diseases.

Interactions between PCSK9 and NLRP3 inflammasome signaling in atherosclerosis

Atherosclerosis is an early pathological basis of numerous cardiovascular events that result in death or disability. Recent studies have described PCSK9 as a novel target for the treatment of atherosclerosis; PCSK9 is capable of degrading LDLR on the surface of hepatocytes through the regulation of lipid metabolism, and it can function as a novel inflammatory modulator in atherosclerosis. Inflammasomes are important intracellular multiprotein complexes that promote the inflammatory response in atherosclerosis. Among inflammasomes, the NLRP3 inflammasome is particularly notable because of its important role in the development of atherosclerotic disease. After activation, NLRP3 forms a complex with ASC and pro-caspase-1, converting pro-caspase-1 into activated caspase-1, which may trigger the release of IL-1β and IL-18 and contribute to the inflammatory response. Several recent studies have indicated that there may be interactions between PCSK9 and the NLRP3 inflammasome, which may contribute to the inflammatory response that drives atherosclerosis development and progression. On the one hand, the NLRP3 inflammasome plays an important role via IL-1β in regulating PCSK9 secretion. On the other hand, PCSK9 regulates caspase-1-dependent pyroptosis by initiating mtDNA damage and activating NLRP3 inflammasome signaling. This paper reviews the mechanisms underlying PCSK9 and NLRP3 inflammasome activation in the context of atherosclerosis. Furthermore, we describe the current understanding of the specific molecular mechanism underlying the interactions between PCSK9 and NLRP3 inflammasome signaling as well as the drug repositioning events that influence vascular cells and exert beneficial antiatherosclerotic effects. This review may provide a new therapeutic direction for the effective prevention and treatment of atherosclerosis in the clinic.

The emerging role of pyroptosis-related inflammasome pathway in atherosclerosis

Atherosclerosis (AS), a chronic sterile inflammatory disorder, is one of the leading causes of mortality worldwide. The dysfunction and unnatural death of plaque cells, including vascular endothelial cells (VEC), macrophages, and vascular smooth muscle cells (VSMC), are crucial factors in the progression of AS. Pyroptosis was described as a form of cell death at least two decades ago. It is featured by plasma membrane swelling and rupture, cell lysis, and consequent robust release of cytosolic contents and pro-inflammatory mediators, including interleukin-1β (IL-1β), IL-18, and high mobility group box 1 (HMGB1). Pyroptosis of plaque cells is commonly observed in the initiation and development of AS, and the levels of pyroptosis-related proteins are positively correlated with plaque instability, indicating the crucial contribution of pyroptosis to atherogenesis. Furthermore, studies have also identified some candidate anti-atherogenic agents targeting plaque cell pyroptosis. Herein, we summarize the research progress in understating (1) the discovery and definition of pyroptosis; (2) the characterization and molecular mechanisms of pyroptosis; (3) the regulatory mechanisms of pyroptosis in VEC, macrophage, and VSMC, as well as their potential role in AS progression, aimed at providing therapeutic targets for the prevention and treatment of AS.

Salvianolic acid A regulates pyroptosis of endothelial cells via directly targeting PKM2 and ameliorates diabetic atherosclerosis

Rescuing endothelial cells from pyroptotic cell death emerges as a potential therapeutic strategy to combat diabetic atherosclerosis. Salvianolic acid A (SAA) is a major water-soluble phenolic acid in the Salvia miltiorrhiza Bunge, which has been used in traditional Chinese medicine (TCM) and health food products for a long time. This study investigated whether SAA-regulated pyruvate kinase M2 (PKM2) functions to protect endothelial cells. In streptozotocin (STZ)-induced diabetic ApoE-/- mice subjected to a Western diet, SAA attenuated atherosclerotic plaque formation and inhibited pathological changes in the aorta. In addition, SAA significantly prevented NLRP3 inflammasome activation and pyroptosis of endothelial cells in the diabetic atherosclerotic aortic sinus or those exposed to high glucose. Mechanistically, PKM2 was verified to be the main target of SAA. We further revealed that SAA directly interacts with PKM2 at its activator pocket, inhibits phosphorylation of Y105, and hinders the nuclear translocation of PKM2. Also, SAA consistently decreased high glucose-induced overproduction of lactate and partially lactate-dependent phosphorylation of PKR (a regulator of the NLRP3 inflammasome). Further assay on Phenylalanine (PKM2 activity inhibitor) proved that SAA exhibits the function in high glucose-induced pyroptosis of endothelial cells dependently on PKM2 regulation. Furthermore, an assay on c16 (inhibitor of PKR activity) with co-phenylalanine demonstrated that the regulation of the phosphorylated PKR partially drives PKM2-dependent SAA modulation of cell pyroptosis. Therefore, this article reports on the novel function of SAA in the pyroptosis of endothelial cells and diabetic atherosclerosis, which provides important insights into immunometabolism reprogramming that is important for diabetic cardiovascular disease complications therapy.

Role of metabolic reprogramming in pro-inflammatory cytokine secretion from LPS or silica-activated macrophages

In the lungs, macrophages constitute the first line of defense against pathogens and foreign bodies and play a fundamental role in maintaining tissue homeostasis. Activated macrophages show altered immunometabolism and metabolic changes governing immune effector mechanisms, such as cytokine secretion characterizing their classic (M1) or alternative (M2) activation. Lipopolysaccharide (LPS)-stimulated macrophages demonstrate enhanced glycolysis, blocked succinate dehydrogenase (SDH), and increased secretion of interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α). Glycolysis suppression using 2 deoxyglucose in LPS-stimulated macrophages inhibits IL-1β secretion, but not TNF-α, indicating metabolic pathway specificity that determines cytokine production. In contrast to LPS, the nature of the immunometabolic responses induced by non-organic particles, such as silica, in macrophages, its contribution to cytokine specification, and disease pathogenesis are not well understood. Silica-stimulated macrophages activate pattern recognition receptors (PRRs) and NLRP3 inflammasome and release IL-1β, TNF-α, and interferons, which are the key mediators of silicosis pathogenesis. In contrast to bacteria, silica particles cannot be degraded, and the persistent macrophage activation results in an increased NADPH oxidase (Phox) activation and mitochondrial reactive oxygen species (ROS) production, ultimately leading to macrophage death and release of silica particles that perpetuate inflammation. In this manuscript, we reviewed the effects of silica on macrophage mitochondrial respiration and central carbon metabolism determining cytokine specification responsible for the sustained inflammatory responses in the lungs.

Naringenin Alleviates Renal Ischemia Reperfusion Injury by Suppressing ER Stress-Induced Pyroptosis and Apoptosis through Activating Nrf2/HO-1 Signaling Pathway

Endoplasmic reticulum (ER) stress, pyroptosis, and apoptosis are critical molecular events in the occurrence and progress of renal ischemia reperfusion (I/R) injury. Naringenin (4′,5,7-trihydroxyflavanone) is one of the most widely consumed flavonoids with powerful antioxidant and anti-inflammatory activities. However, whether naringenin is able to relieve renal I/R injury and corresponding mechanisms have not been fully clarified. This study was aimed at exploring its role and relevant mechanisms in renal I/R injury. The C57Bl/6 mice were randomly assigned to receive administration with naringenin (50 mg/kg/d) or sterile saline (1.0 mL/d) for 3 d by gavage and suffered from renal I/R surgery. One specific ER stress inhibitor, 4-phenylbutyric acid (4-PBA, 100 mg/kg/d), was intraperitoneally administered to validate the regulation of ER stress on pyroptosis and apoptosis. Cultured HK-2 cells went through the process of hypoxia/reoxygenation (H/R) to perform cellular experiments with the incubation of naringenin (200 μM), 4-PBA (5 mM), or brusatol (400 nM). The animal results verified that naringenin obviously relieved renal I/R injury, while it refined renal function and attenuated tissue structural damage. Furthermore, naringenin treatment inhibited I/R-induced ER stress as well as pyroptosis and apoptosis as indicated by decreased levels of specific biomarkers such as GRP78, CHOP, caspase-12, NLRP3, ASC, caspase-11, caspase-4, caspase-1, IL-1β, GSDMD-N, BAX, and cleaved caspase-3 in animals and HK-2 cells. Besides, the upregulated expression of Nrf2 and HO-1 proteins after naringenin treatment suggested that naringenin activated the Nrf2/HO-1 signaling pathway, which was again authenticated by the usage of brusatol (Bru), one unique inhibitor of the Nrf2 pathway. Importantly, the application of 4-PBA showed that renal I/R-generated pyroptosis and apoptosis were able to be regulated by ER stress in vivo and in vitro. In conclusion, naringenin suppressed ER stress by activating Nrf2/HO-1 signaling pathway and further alleviated pyroptosis and apoptosis to protect renal against I/R injury.

Muscone with Attenuation of Neuroinflammation and Oxidative Stress Exerts Antidepressant-Like Effect in Mouse Model of Chronic Restraint Stress

Major depressive disorder (MDD) is a common mental disorder with high morbidity. Stress negatively affects for MDD development, whereby transport of stress-induced inflammatory mediators to the central nervous system (CNS) is associated with the etiology of mood disorders. Muscone is a pharmacologically active ingredient isolated from musk, with anti-inflammatory and neuroprotective effects. We hypothesized that muscone may ameliorate depression-like behavior by regulating inflammatory responses. To test this hypothesis, we used the chronic restraint stress (CRS) depression model, and CRS mice were treated with muscone (10 mg/kg, i.g., respectively) for 14 days. The effects of the drug on depressive-like behaviors were evaluated via the open field test (OFT), novelty-suppressed feeding test (NSFT), tail suspension test (TST), and forced swimming test (FST). Quantitative reverse transcription-PCR (qRT-PCR) was utilized to assess levels of proinflammatory cytokines (IL-6, TNF-α, COX2, and IL-1) and the anti-inflammatory cytokines (IL-4 and IL-10). We also determined levels of oxidative stress factors (malondialdehyde, superoxide dismutase, and glutathione peroxidase), as well as doublecortin (DCX) expression by immunofluorescence. The results showed that depression-like behavior and inflammatory levels were improved after muscone treatment. Muscone also significantly improved neurogenesis in the CRS mouse hippocampus and decreased oxidative stress in both the central and peripheral nervous systems. In conclusion, this work is the first to demonstrate that muscone has an antidepressant effect using a CRS model. Oxidative stress, neurogenesis, and inflammatory pathways are key factors affected by the drug and may represent new therapeutic targets to treat MDD, in this impact. These results may represent a new therapeutic target for MDD.

Knockdown of lncRNA H19 alleviates ox-LDL-induced HCAECs inflammation and injury by mediating miR-20a-5p/HDAC4 axis

BACKGROUND

Coronary artery disease (CAD) seriously disturbs the life of people. LncRNA H19 is reported to promote the progression of CAD; Nevertheless, the detailed mechanism by which H19 modulates CAD development is unclear.

METHODS

Clinical samples of CAD patients were collected, meanwhile we established in vitro and in vivo models of CAD by treating HCAECs with ox-LDL and feeding ApoE^-/- mice with high fat diets (HFD). MTT assay was adopted to assess the cell viability. Transwell detection was applied to test the migration, and apoptosis was tested by flow cytometry. The levels of inflammatory cytokines were examined by ELISA. The relation among H19, miR-20a-5p and HDAC4 was explored by dual luciferase reporter and RIP assay.

RESULTS

H19 and HDAC4 levels were elevated, while miR-20a-5p was reduced in plasma of CAD patients and ox-LDL-treated HCAECs. ox-LDL increased H19 level and induced apoptosis and inflammation in HCAECs, while silencing of H19 rescued this phenomenon. In addition, the level of H19 was negatively correlated with miR-20a-5p, and miR-20a-5p inhibitor restored the effect of H19 silencing on HCAECs function. HDAC4 was the downstream mRNA of miR-20a-5p, and miR-20a-5p upregulation reversed ox-LDL-induced HCAECs injury through targeting HDAC4. Furthermore, H19 silencing significantly alleviated the coronary atherosclerotic plaques and inhibited the inflammatory responses in vivo.

CONCLUSIONS

We proved that knockdown of H19 alleviated ox-LDL-induced HCAECs injury via miR-20a-5p/HDAC4 axis, which might provide a new tactics against CAD.

IGF2BP1-regulated expression of ERRα is involved in metabolic reprogramming of chemotherapy resistant osteosarcoma cells

Doxorubicin (Dox) is the standard treatment approach for osteosarcoma (OS), while acquired drug resistance seriously attenuates its treatment efficiency. The present study aimed to investigate the potential roles of metabolic reprogramming and the related regulatory mechanism in Dox-resistant OS cells. The results showed that the ATP levels, lactate generation, glucose consumption and oxygen consumption rate were significantly increased in Dox-resistant OS cells compared with parental cells. Furthermore, the results revealed that the increased expression of estrogen-related receptor alpha (ERRα) was involved in metabolic reprogramming in chemotherapy resistant OS cells, since targeted inhibition of ERRα restored the shifting of metabolic profiles. Mechanistic analysis indicated that the mRNA stability, rather than ERRα transcription was markedly increased in chemoresistant OS cells. Therefore, it was hypothesized that the 3ʹ-untranslated region of ERRα mRNA was methylated by N⁶-methyladenine, which could further recruit insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) to suppress mRNA decay and increase mRNA stability. IGF2BP1 knockdown downregulated ERRα and reversed the metabolic alteration of resistant OS cells. Additionally, the oncogenic effect of the IGF2BP1/ERRα axis on Dox-resistant OS cells was verified by in vitro and in vivo experiments. Clinical analysis also revealed that the expression levels of IGF2BP1 and ERRα were associated with the clinical progression of OS. Collectively, the current study suggested that the IGF2BP1/ERRα axis could regulate metabolic reprogramming to contribute to the chemoresistance of OS cells.

Brain-Derived Neurotrophic Factor And Coronary Artery Disease

Coronary artery disease (CAD) is defined as myocardial damage developing as a result of its organic and functional changes, and leading to impaired blood flow through the coronary arteries. An important pathogenetic component of CAD is atherosclerosis. Currently, key aspects of the molecular relationship between inflammation and atherosclerosis are being actively studied, the immunometabolic theory of atherosclerosis is being discussed, along with an involvement of perivascular adipose tissue in the pathogenesis of this pathology, due to its ability to respond to atherogenic stimuli via developing inflammatory reactions. Evidence has been accumulated that in patients with CAD, both in their blood and perivascular adipose tissue, the level of neurotrophic factors (in particular, brain-derived neurotrophic factor, BDNF) changes, which may be a promising area of research from the standpoint of studying this factor as a therapeutic target for atherosclerosis in CAD. Neurotrophic growth factors control the functioning of both immune and nervous systems, and the balance of energy metabolism and innervation of adipose tissue. They affect vascular homeostasis, and are also involved in causing and stopping inflammation. Currently, there are data on the role of BDNF in the pathogenesis of cardiovascular, neurodegenerative and metabolic diseases, and on the effect of polyunsaturated fatty acids and eicosanoids on the level of BDNF and, accordingly, the development and progression of coronary artery atherosclerosis. Our review summarizes published data (2019-2021) on the pathophysiological and pathogenetic mechanisms of the relationship between BDNF and CAD (atherosclerosis).

Effects of two different exercise paradigms on cardiac function, BDNF-TrkB expression, and myocardial protection in the presence and absence of Western diet

Background

Brain-derived neurotrophic factor (BDNF) -tropomyosin-related kinase receptor B (TrkB) signaling is a vital regulator of myocardial performance. Here, we tested the impact of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on heart function, metabolic parameters, and serum/cardiac BDNF (with its TrkB receptor) in animals fed a Western (WD) or regular diet (ND). Further, myocardial expression of pro-inflammatory cytokine interleukin-18 (IL-18) and cardioprotective molecule heme oxygens-1 (HO-1) were monitored.

Methods

Wistar rats were divided into HIIT, MICT, and sedentary (SED), all fed a WD or ND, for 12 weeks. Heart function, protein expression, and serum factors were assessed via echocardiography, western blotting, and ELISA, respectively.

Results

WD plus SED caused insulin resistance, dyslipidemia, visceral fat deposition, serum BDNF depletion as well as cardiac upregulation of IL-18 and downregulation of HO-1, without affecting, heart function and BDNF-TrkB expression. The cardiometabolic risk factors, serum BDNF losses, and IL-18 overexpression were similarly obviated by HIIT and MICT, although HO-1 expression was boosted by HIIT exclusively (even in ND). HIIT enhanced heart function, regardless of the diet. HIIT augmented cardiac BDNF expression, with a significant difference between ND and WD. Likewise, HIIT instigated TrkB expression only in ND.

Conclusions

HIIT and MICT can cope with myocardial inflammation and cardiometabolic risk factors in WD consumers and, exclusively, HIIT may grant further protection by increasing heart function, BDNF-TrkB expression, and HO-1 expression. Thus, the HIIT paradigm should be considered as a preference for subjects who require heart function to be preserved or enhanced.

KLF2 mediates the suppressive effect of BDNF on diabetic intimal calcification by inhibiting HK1 induced endothelial-to-mesenchymal transition

Diabetic vascular calcification in the arterial intima is closely associated with endothelial-to-mesenchymal transition (EndMT). Glucose metabolism reprogramming is involved in EndMT. Although brain-derived neurotrophic factor (BDNF) and Krüppel-like family of transcription factor 2 (KLF2) play protective roles in the physiological activity of the vascular endothelium, the underlying mechanisms are unclear. Human umbilical vein endothelial cells (HUVECs) were incubated with diabetic osteogenic medium (DOM) to induce EndMT and accelerate osteogenic differentiation. Glycolysis in HUVECs was assessed by monitoring glucose uptake, lactate production, extracellular acidification rate and expression of key glycolytic enzymes. DOM induced EndMT and accelerated osteo-induction in HUVECs, which was alleviated by BDNF/tropomyosin receptor kinase B (TrkB) pathway. Mechanistically, DOM caused hyperactivation of glycolysis in HUVECs and inhibition of the BDNF/TrkB pathway. BDNF preserved KLF2 and downregulated hexokinase 1 (HK1) in HUVECs after DOM treatment. Furthermore, KLF2 interacted with HK1. Increased KLF2 alleviated HK1-mediated glucose metabolism abnormality. HK1 knockdown or a targeted glycolysis inhibitor suppressed EndMT, apoptosis, inflammation and vascular calcification of HUVECs after DOM exposure. This study suggests that KLF2 mediates the suppressive effect of BDNF on diabetic intimal calcification by inhibiting HK1-induced glucose metabolism reprogramming and the EndMT process.

Sirtuin-1 - Mediated NF-κB Pathway Modulation to Mitigate Inflammasome Signaling and Cellular Apoptosis is One of the Neuroprotective Effects of Intra-arterial Mesenchymal Stem Cell Therapy Following Ischemic Stroke

AIM

Stroke results in long term serious disability that affect millions across the globe. Several clinical and preclinical studies have reinforced the therapeutic use of stem cells in stroke patients to enhance their quality of life. Previous studies from our lab have demonstrated that 1*10⁵ allogeneic bone marrow-derived mesenchymal stem cells (BM-MSCs) when given intraarterially (IA) render neuroprotection by modulating the expression of inflammasomes. Sirtuins are a class of important deacylases having a significant role in cellular functioning. Sirtuin-1 (SIRT-1) is an important enzyme essential for regulating cellular metabolism, which is reduced following an ischemic episode. The present study aims to unviel the role of MSCs in regulating the brain SIRT-1 levels following stroke and the involvement of SIRT-1 in regulating inflammasome signaling to reduce cellular apoptosis towards rendering neuroprotection.

MATERIALS AND METHODS

6 h post-reversible middle cerebral artery occlusion (MCAo), ovariectomized Sprague Dawley (SD) rats were infused intraarterially with 1*10⁵ MSCs. 24 h after MCAo animals were examined for functional and behavioral outcomes. Brains were collected for assessing size of infarct and neuronal morphology. Molecular and immunofluroscence studies were also performed for assessing changes in gene and protein expressions. Extent of apoptosis was also determined in different groups. Inhibition study with SIRT-1 specific inhibitor EX-527 was also performed.

RESULTS

A reduction in infarct size and improvement in motor functional and behavioral outcomes following infusion of MSCs IA at 6 h post-stroke was observed. Increase in average neuronal density and neuronal length was also seen. Increased expression of SIRT-1, BDNF and concomitant reduction in the expression of different inflammatory and apoptotic markers in the brain cortical regions were observed following MSCs treatment.

CONCLUSION

Our study provides a preliminary evidence that post-stroke IA MSCs therapy regulates SIRT-1 to modulate NF-κB pathway to mitigate inflammasome signaling and cellular apoptosis. This study using IA approach for administering MSCs is highly relevant clinically. Our study is the first to report that neuroprotective effects of IA MSCs in rodent focal ischemia is mediated by SIRT-1 regulation of inflammasome signaling.

Autophagy, Pyroptosis, and Ferroptosis: New Regulatory Mechanisms for Atherosclerosis

Atherosclerosis is a chronic inflammatory disorder characterized by the gradual buildup of plaques within the vessel wall of middle-sized and large arteries. The occurrence and development of atherosclerosis and the rupture of plaques are related to the injury of vascular cells, including endothelial cells, smooth muscle cells, and macrophages. Autophagy is a subcellular process that plays an important role in the degradation of proteins and damaged organelles, and the autophagy disorder of vascular cells is closely related to atherosclerosis. Pyroptosis is a proinflammatory form of regulated cell death, while ferroptosis is a form of regulated nonapoptotic cell death involving overwhelming iron-dependent lipid peroxidation. Both of them exhibit distinct features from apoptosis, necrosis, and autophagy in morphology, biochemistry, and genetics. However, a growing body of evidence suggests that pyroptosis and ferroptosis interact with autophagy and participate in the development of cancers, degenerative brain diseases and cardiovascular diseases. This review updated the current understanding of autophagy, pyroptosis, and ferroptosis, finding potential links and their effects on atherogenesis and plaque stability, thus providing ways to develop new pharmacological strategies to address atherosclerosis and stabilize vulnerable, ruptured plaques.

The Role of KLF2 in the Regulation of Atherosclerosis Development and Potential Use of KLF2-Targeted Therapy

Kruppel like factor 2 (KLF2) is a mechanosensitive transcription factor participating in the regulation of vascular endothelial cells metabolism. Activating KLF2 in endothelial cells induces eNOS (endothelial nitric oxide synthase) expression, subsequent NO (nitric oxide) release, and vasodilatory effect. In addition, many KLF2-regulated genes participate in the anti-thrombotic, antioxidant, and anti-inflammatory activities, thereby preventing atherosclerosis development and progression. In this review, we summarise recent evidence suggesting that KLF2 plays a major role in regulating atheroprotective effects in endothelial cells. We also discuss several recently identified repurposed drugs and natural plant-based bioactive compounds with KLF2-mediated atheroprotective activities. Herein, we present a comprehensive overview of the role of KLF2 in atherosclerosis and as a pharmacological target for different drugs and natural compounds and highlight the potential application of these phytochemicals for the treatment of atherosclerosis.

A Novel Pyroptosis-Associated Long Noncoding RNA Signature to Predict the Prognosis of Patients with Colorectal Cancer

Purpose

Pyroptosis plays an important role in tumor progression. However, there is no pyroptosis-associated long noncoding RNA (lncRNA) signature to predict the prognosis of patients with colorectal cancer (CRC).

Materials and Methods

The RNA sequencing data (RNA-seq) and corresponding clinical information relating to CRC patients were obtained from the Cancer Genome Atlas (TCGA) database and the GSE39582 dataset. Univariate Cox regression analysis was used to identify pyroptosis-associated lncRNAs linked to CRC prognosis. Subsequently, multivariate Cox regression analysis was performed to construct a pyroptosis-associated lncRNAs signature within the TCGA cohort, which was then validated using the GSE39582 dataset. We used Kaplan-Meier (K-M) analysis, principal component analysis (PCA), and receiver operating characteristic curve (ROC) analysis to evaluate our novel lncRNA signature. Finally, gene set enrichment analysis (GSEA) was performed to explore the potential function of the lncRNA signature.

Results

We constructed a pyroptosis-associated lncRNA signature comprising four lncRNAs (ELFN1-AS1, PCAT6, TNRC6C-AS1, and ZEB1-AS1). CRC patients were subdivided into high- and low-risk groups based on median risk scores. The results of the K-M, PCA, and ROC analyses showed that this signature could accurately predict the prognosis of CRC patients. Univariate and multivariate Cox regression analyses showed that the pyroptosis-associated signature was an independent prognostic factor. Functional analysis suggested that tumor-associated pathways were enriched for in the high-risk CRC patient group.

Conclusion

Our study established an effective prognostic signature for CRC patients that may represent a potential therapeutic target.

Rabeprazole inhibits inflammatory reaction by inhibition of cell pyroptosis in gastric epithelial cells

Background

Helicobacter pylori (H. pylori) is a common pathogen in development of peptic ulcers with pyroptosis. Rabeprazole, a critical component of standard triple therapy, has been widely used as the first-line regimen for H. pylori infectious treatment. The aim of this study to explore the function of Rabeprazole on cell pyroptosis in vitro.

Methods

The clinical sample from patients diagnosed with or without H. pylori-infection were collected to analyze by Immunohistochemistry (IHC). Real-time quantitative PCR (qPCR), western blot (WB) and enzyme linked immunosorbent assay (Elisa) were performed to analyze the effect of Rabeprazole on cell pyroptosis, including LDH, IL-1β and IL-18.

Results

In this study, we showed that Rabeprazole regulated a phenomenon of cell pyroptosis as confirmed by lactate dehydrogenase (LDH) assay. Further results showed that Rabeprazole inhibited cell pyroptosis in gastric epithelial cells by alleviating GSDMD-executed pyroptosis, leading to decrease IL-1β and IL-18 mature and secretion, which is attributed to NLRP3 inflammasome activation inhibition. Further analysis showed that ASC, NLRP3 and Caspase-1, was significantly repressed in response to Rabeprazole stimulation, resulting in decreasing cleaved-caspase-1 expression. Most important, NLRP3 and GSDMD is significantly increased in gastric tissue of patients with H. pylori infection.

Conclusion

These findings revealed a critical role of Rabeprazole in cell pyroptosis in patients with H. pylori infection, suggesting that targeting cell pyroptosis is an alternative strategy in improving H. pylori treatment.

Pyroptosis in the Initiation and Progression of Atherosclerosis

Pyroptosis, a newly discovered form of programmed cell death, is characterized by cell swelling, the protrusion of large bubbles from the plasma membrane and cell lysis. This death pathway is mediated by the pore formation of gasdermin D (GSDMD), which is activated by human caspase-1/caspase-4/caspase-5 (or mouse caspase-1/caspase11), and followed with the releasing of both cell contents and proinflammatory cytokines. Pyroptosis was initially found to function as an innate immune effector mechanism to facilitate host defense against pathogenic microorganisms, and subsequent studies revealed that pyroptosis also plays an eventful role in inflammatory immune diseases and tumor resistance. Recent studies have also shown that pyroptosis is involved in the initiation, the progression and complications of atherosclerosis. Here, we provide an overview of the role of pyroptosis in atherosclerosis by focusing on three important participating cells: ECs, macrophages, and SMCs. In addition, we also summarized drugs and stimuli that regulate the progression of atherosclerosis by influencing cell pyroptosis.

Mitochondria Homeostasis and Oxidant/Antioxidant Balance in Skeletal Muscle-Do Myokines Play a Role?

Mitochondria are the cellular powerhouses that generate adenosine triphosphate (ATP) to substantiate various biochemical activities. Instead of being a static intracellular structure, they are dynamic organelles that perform constant structural and functional remodeling in response to different metabolic stresses. In situations that require a high ATP supply, new mitochondria are assembled (mitochondrial biogenesis) or formed by fusing the existing mitochondria (mitochondrial fusion) to maximize the oxidative capacity. On the other hand, nutrient overload may produce detrimental metabolites such as reactive oxidative species (ROS) that wreck the organelle, leading to the split of damaged mitochondria (mitofission) for clearance (mitophagy). These vital processes are tightly regulated by a sophisticated quality control system involving energy sensing, intracellular membrane interaction, autophagy, and proteasomal degradation to optimize the number of healthy mitochondria. The effective mitochondrial surveillance is particularly important to skeletal muscle fitness because of its large tissue mass as well as its high metabolic activities for supporting the intensive myofiber contractility. Indeed, the failure of the mitochondrial quality control system in skeletal muscle is associated with diseases such as insulin resistance, aging, and muscle wasting. While the mitochondrial dynamics in cells are believed to be intrinsically controlled by the energy content and nutrient availability, other upstream regulators such as hormonal signals from distal organs or factors generated by the muscle itself may also play a critical role. It is now clear that skeletal muscle actively participates in systemic energy homeostasis via producing hundreds of myokines. Acting either as autocrine/paracrine or circulating hormones to crosstalk with other organs, these secretory myokines regulate a large number of physiological activities including insulin sensitivity, fuel utilization, cell differentiation, and appetite behavior. In this article, we will review the mechanism of myokines in mitochondrial quality control and ROS balance, and discuss their translational potential.