HIF-1α Preconditioning Potentiates Antioxidant Activity in Ischemic Injury: The Role of Sequential Administration of Dihydrotanshinone I and Protocatechuic Aldehyde in Cardioprotection

The pathological mechanisms and potential therapeutic drugs for myocardial ischemia reperfusion injury

BACKGROUND

Cardiovascular disease is the main cause of death and disability, with myocardial ischemia being the predominant type that poses a significant threat to humans. Reperfusion, an essential therapeutic approach, promptly reinstates blood circulation to the ischemic myocardium and stands as the most efficacious clinical method for myocardial preservation. Nevertheless, the restoration of blood flow associated with this process can potentially induce myocardial ischemia-reperfusion injury (MIRI), thereby diminishing the effectiveness of reperfusion and impacting patient prognosis. Therefore, it is of great significance to prevent and treat MIRI.

PURPOSE

MIRI is an important factor affecting the prognosis of patients, and there is no specific in-clinic treatment plan. In this review, we have endeavored to summarize its pathological mechanisms and therapeutic drugs to provide more powerful evidence for clinical application.

METHODS

A comprehensive literature review was conducted using PubMed, Web of Science, Embase, Medline and Google Scholar with a core focus on the pathological mechanisms and potential therapeutic drugs of MIRI.

RESULTS

Accumulated evidence revealed that oxidative stress, calcium overload, mitochondrial dysfunction, energy metabolism disorder, ferroptosis, inflammatory reaction, endoplasmic reticulum stress, pyroptosis and autophagy regulation have been shown to participate in the process, and that the occurrence and development of MIRI are related to plenty of signaling pathways. Currently, a range of chemical drugs, natural products, and traditional Chinese medicine (TCM) preparations have demonstrated the ability to mitigate MIRI by targeting various mechanisms.

CONCLUSIONS

At present, most of the research focuses on animal and cell experiments, and the regulatory mechanisms of each signaling pathway are still unclear. The translation of experimental findings into clinical practice remains incomplete, necessitating further exploration through large-scale, multi-center randomized controlled trials. Given the absence of a specific drug for MIRI, the identification of therapeutic agents to reduce myocardial ischemia is of utmost significance. For the future, it is imperative to enhance our understanding of the pathological mechanism underlying MIRI, continuously investigate and develop novel pharmaceutical agents, expedite the clinical translation of these drugs, and foster innovative approaches that integrate TCM with Western medicine. These efforts will facilitate the emergence of fresh perspectives for the clinical management of MIRI.

Hypoxia-inducible factor-1: Regulatory mechanisms and drug therapy in myocardial infarction

Myocardial infarction (MI), an acute cardiovascular disease characterized by coronary artery blockage, inadequate blood supply, and subsequent ischemic necrosis of the myocardium, is one of the leading causes of death. The cellular, physiological, and pathological responses following MI are complex, involving multiple intertwined pathological mechanisms. Hypoxia-inducible factor-1 (HIF-1), a crucial regulator of hypoxia, plays a significant role in of the development of MI by modulating the behavior of various cells such as cardiomyocytes, endothelial cells, macrophages, and fibroblasts under hypoxic conditions. HIF-1 regulates various post-MI adaptive reactions to acute ischemia and hypoxia through various mechanisms. These mechanisms include angiogenesis, energy metabolism, oxidative stress, inflammatory response, and ventricular remodeling. With its crucial role in MI, HIF-1 is expected to significantly influence the treatment of MI. However, the drugs available for the treatment of MI targeting HIF-1 are currently limited, and most contain natural compounds. The development of precision-targeted drugs modulating HIF-1 has therapeutic potential for advancing MI treatment research and development. This study aimed to summarize the regulatory role of HIF-1 in the pathological responses of various cells following MI, the diverse mechanisms of action of HIF-1 in MI, and the potential drugs targeting HIF-1 for treating MI, thus providing the theoretical foundations for potential clinical therapeutic targets.

Dihydrotanshinone I reduces H9c2 cell damage by regulating AKT and MAPK signaling pathways

Cardiovascular disease is the deadliest disease in the world. Previous studies have shown that Dihydrotanshinone I (DHT) can improve cardiac function after myocardial injury. This study aimed to observe the protective effect and mechanism of DHT on H9c2 cells by establishing an oxygen-glucose deprivation/reoxygenation (OGD/R) injury model. By constructing OGD/R injury simulation of H9c2 cells in a myocardial injury model, the proliferation of H9c2 cells treated with DHT concentrations of 0.1 μmol/L were not affected at 24, 48, and 72 h. DHT can significantly reduce the apoptosis of H9c2 cells caused by OGD/R. Compared with the OGD/R group, DHT treatment significantly reduced the level of MDA and increased the level of SOD in cells. DHT treatment of cells can significantly reduce the levels of ROS and Superoxide in mitochondria in H9c2 cells caused by OGD/R and H2O2. DHT significantly reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by OGD/R, and significantly increased the phosphorylation levels of AKT in H9c2 cells. DHT can significantly reduce the oxidative stress damage of H9c2 cells caused by H2O2 and OGD/R, thereby reducing the apoptosis of H9c2 cells. And this may be related to regulating the phosphorylation levels of AKT, ERK, and P38MAPK.

Protocatechuic aldehyde increases pericyte coverage and mitigates pericyte damage to enhance the atherosclerotic plaque stability

Pericyte dysfunction and loss contribute substantially to the destabilization and rupture of atherosclerotic plaques. Protocatechuic aldehyde (PCAD), a natural polyphenol, exerts anti-atherosclerotic effects. However, the effects and mechanisms of this polyphenol on pericyte recruitment, coverage, and pericyte function remain unknown. We here treated apolipoprotein E-deficient mice having high-fat diet-induced atherosclerosis with PCAD. PCAD achieved therapeutic effects similar to rosuvastatin in lowering lipid levels and thus preventing atherosclerosis progression. With PCAD administration, plaque phenotype exhibited higher stability with markedly reduced lesion vulnerability, which is characterized by reduced lipid content and macrophage accumulation, and a consequent increase in collagen deposition. PCAD therapy increased pericyte coverage in the plaques, reduced VEGF-A production, and inhibited intraplaque neovascularization. PCAD promoted pericyte proliferation, adhesion, and migration to mitigate ox-LDL-induced pericyte dysfunction, which thus maintained the capillary network structure and stability. Furthermore, TGFBR1 silencing partially reversed the protective effect exerted by PCAD on human microvascular pericytes. PCAD increased pericyte coverage and impeded ox-LDL-induced damages through TGF-β1/TGFBR1/Smad2/3 signaling. All these novel findings indicated that PCAD increases pericyte coverage and alleviates pericyte damage to improve the stability of atherosclerotic plaques, which is accomplished by regulating TGF-β1/TGFBR1/Smad2/3 signaling in pericytes.

Salvianolic acid A diminishes LDHA-driven aerobic glycolysis to restrain myofibroblasts activation and cardiac fibrosis via blocking Akt/GSK-3β/HIF-1α axis

Myofibroblasts activation intensively contributes to cardiac fibrosis with undefined mechanism. Salvianolic acid A (SAA) is a phenolic component derived from Salvia miltiorrhiza with antifibrotic potency. This study aimed to interrogate the inhibitory effects and underlying mechanism of SAA on myofibroblasts activation and cardiac fibrosis. Antifibrotic effects of SAA were evaluated in mouse myocardial infarction (MI) model and in vitro myofibroblasts activation model. Metabolic regulatory effects and mechanism of SAA were determined using bioenergetic analysis and cross-validated by multiple metabolic inhibitors and siRNA or plasmid targeting Ldha. Finally, Akt/GSK-3β-related upstream regulatory mechanisms were investigated by immunoblot, q-PCR, and cross-validated by specific inhibitors. SAA inhibited cardiac fibroblasts-to-myofibroblasts transition, suppressed collage matrix proteins expression, and effectively attenuated MI-induced collagen deposition and cardiac fibrosis. SAA attenuated myofibroblasts activation and cardiac fibrosis by inhibiting LDHA-driven abnormal aerobic glycolysis. Mechanistically, SAA inhibited Akt/GSK-3β axis and downregulated HIF-1α expression by promoting its degradation via a noncanonical route, and therefore restrained HIF-1α-triggered Ldha gene expression. SAA is an effective component for treating cardiac fibrosis by diminishing LDHA-driven glycolysis during myofibroblasts activation. Targeting metabolism of myofibroblasts might occupy a potential therapeutic strategy for cardiac fibrosis.

Screening and identification of effective components from modified Taohong Siwu decoction for protecting H9c2 cells from damage

We found that modified Taohong Siwu decoction (MTHSWD) had cardioprotective effects after myocardial ischemia-reperfusion injury. This study was to screen the effective components of MTHSWD that have protective effects on H9c2 cell injury through H₂O₂ injury model. Fifty-three active components were screened by CCK8 assay to detect cell viability. The anti-oxidative stress ability was evaluated by detecting the levels of total superoxide dismutase (SOD) and malondialdehyde (MDA) in cells. The anti-apoptotic effect was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL). Finally, the phosphorylation levels of ERK, AKT, and P38MAPK were detected by WB (Western blot) to study the protective mechanism of effective monomers against H9c2 cell injury. Among the 53 active ingredients of MTHSWD, ginsenoside Rb3, levistilide A, ursolic acid, tanshinone I, danshensu, dihydrotanshinone I, and astragaloside I could significantly increase the viability of H9c2 cells. The results of SOD and MDA showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA could significantly reduce the content of lipid peroxide in cells. TUNEL results showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA reduced apoptosis to varying degrees. The tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, and tanshinone I reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by H₂O₂, and the phosphorylation level of ERK was also significantly reduced by danshensu. At the same time, tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, tanshinone I, and danshensu significantly increased AKT phosphorylation level in H9c2 cells. In conclusion, the effective ingredients in MTHSWD provide basic basis and experimental reference for the prevention and treatment of cardiovascular diseases.

Integrated proteomics and phosphoproteomics profiling reveals the cardioprotective mechanism of bioactive compounds derived from Salvia miltiorrhiza Burge

BACKGROUND

Natural products are an important source for discovering novel drugs due to their various pharmacological activities. Salvia miltiorrhiza Burge (Danshen) has been shown to have promising therapeutic potential in the management of heart diseases, making it a candidate for cardiovascular drug discovery. Currently, there is limited quantitative analysis of the phosphorylation levels of Danshen-derived natural products on a proteome-wide, which may bias the study of their mechanisms of action.

PURPOSE

This study aimed to evaluate the global signaling perturbation induced by Danshen-derived bioactive compounds and their potential relationship with myocardial ischemia/reperfusion (IR) injury therapy.

STUDY DESIGN

We employed quantitative proteome and phosphoproteome analysis to identify dysregulated signaling in IR injury hearts from mice. We compared changes induced by Danshen-derived compounds based on IR-associated phospho-events, using an integrative approach that maps relative abundance of proteins and phosphorylation sites.

METHODS

Isobaric chemical tandem mass tags (TMT) labeled multiplexing strategy was used to generate unbiased quantitative proteomics and phosphoproteomics data. Highly accurate and precise TMT quantitation was performed using the Orbitrap Fusion Tribrid Mass Spectrometer with synchronous precursor selection MS3 detection mode. Mass spectrometric raw files were analyzed with MaxQuant (2.0.1.0) and statistical and bioinformatics analysis was conducted with Perseus (1.6.15).

RESULTS

We quantified 3661 proteins and over 11,000 phosphosites in impaired heart tissue of the IR mice model, expanding our knowledge of signaling pathways and other biological processes disrupted in IR injury. Next, 1548 and 5545 differently expressed proteins and phosphosites were identified by quantifying the proteome and phosphoproteome of H9c2 cells treated by five Danshen bioactive compounds respectively. Results revealed the vast differences in abilities of five Danshen-derived bioactive compounds to regulate phosphorylation modifications in cardiomyocytes, with dihydrotanshinone I (DHT) showing potential for protecting against IR injury by modulating the AMPK/mTOR signaling pathway.

CONCLUSIONS

This study provides a new strategy for analyzing drug/natural product-regulated phosphorylation modification levels on a proteome-wide scale, leading to a better understanding of cell signaling pathways and downstream phenotypic responses.

Protocatechuic Aldehyde Alleviates d -Galactose-Induced Cardiomyocyte Senescence by Regulating the TCF3/ATG5 Axis

ABSTRACT

Cardiomyocyte senescence is an independent risk factor for cardiovascular diseases. Protocatechuic aldehyde (PCA) is a natural chemical in the Chinese medicinal herb Salvia miltiorrhiza . PCA could protect against oxidative stress and inflammation in the cardiovascular system. In present study, we treated H9C2 cells with d -galactose to establish an in vitro model of cardiomyocyte senescence and investigated the role and underlying mechanisms of PCA in myocardial cell senescence. It was found that d -galactose induced transcription factor 3 (TCF3) expression and decreased autophagy-related genes 5 (ATG5) expression. Meanwhile, inflammation and senescence were exacerbated by d -galactose. TCF3 transcriptionally inhibited ATG5 expression. TCF3 knockdown abolished the effects of d -galactose on H9C2 by activating ATG5-mediated autophagy. PCA hindered TCF3 and inflammation to alleviate the d -galactose-induced senescence of H9C2 cells in a dose-dependent manner. Whereas, the anti-inflammation and anti-senescence effects of PCA were reversed by TCF3 knockdown. Furthermore, absence of ATG5 partially eliminated the impacts of PCA on H9C2 cells treated with d -galactose. Conclusively, PCA alleviated d -galactose-induced senescence by downregulating TCF3, promoting ATG5-mediated autophagy, and inhibiting inflammation in H9C2 cells. These results elucidated the potential mechanism by which PCA alleviated cardiomyocyte senescence and enabled its application in treating cardiomyocyte senescence.

A Pharmacological Review of Tanshinones, Naturally Occurring Monomers from Salvia miltiorrhiza for the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVDs) are a set of heart and blood vessel disorders that include coronary heart disease (CHD), rheumatic heart disease, and other conditions. Traditional Chinese Medicine (TCM) has definite effects on CVDs due to its multitarget and multicomponent properties, which are gradually gaining national attention. Tanshinones, the major active chemical compounds extracted from Salvia miltiorrhiza, exhibit beneficial improvement on multiple diseases, especially CVDs. At the level of biological activities, they play significant roles, including anti-inflammation, anti-oxidation, anti-apoptosis and anti-necroptosis, anti-hypertrophy, vasodilation, angiogenesis, combat against proliferation and migration of smooth muscle cells (SMCs), as well as anti-myocardial fibrosis and ventricular remodeling, which are all effective strategies in preventing and treating CVDs. Additionally, at the cellular level, Tanshinones produce marked effects on cardiomyocytes, macrophages, endothelia, SMCs, and fibroblasts in myocardia. In this review, we have summarized a brief overview of the chemical structures and pharmacological effects of Tanshinones as a CVD treatment to expound on different pharmacological properties in various cell types in myocardia.

Dihydrotanshinone I preconditions myocardium against ischemic injury via PKM2 glutathionylation sensitive to ROS

Ischemic preconditioning (IPC) is a potential intervention known to protect the heart against ischemia/reperfusion injury, but its role in the no-reflow phenomenon that follows reperfusion is unclear. Dihydrotanshinone I (DT) is a natural compound and this study illustrates its role in cardiac ischemic injury from the aspect of IPC. Pretreatment with DT induced modest ROS production and protected cardiomyocytes against oxygen and glucose deprivation (OGD), but the protection was prevented by a ROS scavenger. In addition, DT administration protected the heart against isoprenaline challenge. Mechanistically, PKM2 reacted to transient ROS via oxidization at Cys423/Cys424, leading to glutathionylation and nuclear translocation in dimer form. In the nucleus, PKM2 served as a co-factor to promote HIF-1α-dependent gene induction, contributing to adaptive responses. In mice subjected to permanent coronary ligation, cardiac-specific knockdown of Pkm2 blocked DT-mediated preconditioning protection, which was rescued by overexpression of wild-type Pkm2, rather than Cys423/424-mutated Pkm2. In conclusion, PKM2 is sensitive to oxidation, and subsequent glutathionylation promotes its nuclear translocation. Although IPC has been viewed as a protective means against reperfusion injury, our study reveals its potential role in protection of the heart from no-reflow ischemia.

Aqueous extract of Salvia miltiorrhiza Bunge reduces blood pressure through inhibiting oxidative stress, inflammation and fibrosis of adventitia in primary hypertension

Background: Hypertension is a major risk factor for cardiovascular diseases and the leading cause of mortality worldwide. Despite the availability of antihypertensive drugs, alternative treatments are needed due to the adverse events associated with their use. Previous studies have shown that SABP, a combination of aqueous active metabolites of Salvia Miltiorrhiza Bunge DSS, Sal-A, Sal-B and PAL, has a significant antihypertensive effect. However, the underlying mechanisms remain unknown. Objective: This study aimed to determine the effects of SABP on vascular inflammation, oxidative stress, and vascular remodeling in spontaneously hypertensive rats (SHRs). Additionally, the response of adventitial fibroblasts in SHRs to SABP treatment was also studied, including their proliferation, differentiation, and migration. Methods: SABP or perindopril (positive control) were administered intraperitoneally to SHRs, and systolic blood pressure was measured using a tail-cuff approach. The effects of SABP on oxidative stress, inflammation, and vascular remodeling were investigated by transmission electron microscopy, histochemical staining, and Western blot. Adventitial fibroblasts were isolated and cultured from the adventitia of thoracic aorta in SHR and WKY rats. CCK8 assay, wound healing method and immunostaining were used to observe the effect of SABP on fibroblasts proliferation, migration and transformation into myofibroblasts. Moreover, Western blot analysis was also performed to detect the proteins related to oxidative stress, inflammation and fibrosis in adventitial fibroblasts. Results: SHRs displayed higher blood pressure with significant vascular remodeling compared to WKY rats. The thoracic aorta and adventitial fibroblasts of SHRs exhibited significant oxidative stress, inflammation and fibrosis. SABP treatment repressed oxidative stress, inflammatory reaction and vascular remodeling of thoracic aorta in SHR through the ROS/TLR4/NF-κB signaling pathway, and inhibited fibrosis of thoracic aorta. Additionally, SABP inhibited the proliferation and migration of adventitial fibroblasts and their transformation to myofibroblasts in vitro through the TGFβ/Smad3 signaling pathway. Conclusion: These findings suggest that SABP have potential as an alternative treatment for hypertension by ameliorating oxidative stress, inflammation and fibrosis. Further research is needed to fully understand the mechanisms underlying the effects of SABP.

Effects of Pine Needle Extracts on the Degradation of LLDPE

Polyolefin suffers from degradation during processing and application. To prolong the service life, antioxidants are needed in the packing formula of polyolefin products. The usage of natural antioxidants could avoid potential health hazards aroused by synthetic ones. Pine needles have long lives and hardly rot, suggesting their high resistance to degradation. To provide a new candidate of natural antioxidants and add more value to pine needles, pine needle extracts (PNE) were investigated as the antioxidant of linear low-density polyethylene (LLDPE). PNE-modified LLDPE (PE-PNE) exhibited much better short-term and long-term aging resistance than pure LLDPE (PE): Oxidation induction time (OIT) of PE-PNE was 52 times higher than that of PE, and the increments of carbonyl index (CI) of PE-PNE-1st samples placed under daylight and in the dark were approximately 75% and 63% of PE under the same conditions. It could be attributed to the attractive antioxidant capacity of PNE (IC₅₀ of DPPH radical scavenging was 115 μg/mL). In addition, the PE-PNE sample showed high processing stability and maintenance of the mechanical property during multiple extrusions: only a 0.2 g/10 min decrease in melting flow rate was found after five extrusions; the tensile strength and elongation at break were almost unchanged. All results reveal that pine needle extracts could play a role in LLDPE stabilization. Moreover, as pine needles are mainly considered a kind of waste, the present study would benefit the budget-reducing polyolefin industry.

Research progress on effects of traditional Chinese medicine on myocardial ischemia-reperfusion injury: A review

Ischemic heart disease (IHD) is a high-risk disease in the middle-aged and elderly population. The ischemic heart may be further damaged after reperfusion therapy with percutaneous coronary intervention (PCI) and other methods, namely, myocardial ischemia-reperfusion injury (MIRI), which further affects revascularization and hinders patient rehabilitation. Therefore, the investigation of new therapies against MIRI has drawn great global attention. Within the long history of the prevention and treatment of MIRI, traditional Chinese medicine (TCM) has increasingly been recognized by the scientific community for its multi-component and multi-target effects. These multi-target effects provide a conspicuous advantage to the anti-MIRI of TCM to overcome the shortcomings of single-component drugs, thereby pointing toward a novel avenue for the treatment of MIRI. However, very few reviews have summarized the currently available anti-MIRI of TCM. Therefore, a systematic data mining of TCM for protecting against MIRI will certainly accelerate the processes of drug discovery and help to identify safe candidates with synergistic formulations. The present review aims to describe TCM-based research in MIRI treatment through electronic retrieval of articles, patents, and ethnopharmacology documents. This review reported the progress of research on the active ingredients, efficacy, and underlying mechanism of anti-MIRI in TCM and TCM formulas, provided scientific support to the clinical use of TCM in the treatment of MIRI, and revealed the corresponding clinical significance and development prospects of TCM in treating MIRI.

Disturbance of Hypoxia Response and Its Implications in Kidney Diseases

Significance: The disturbance of the hypoxia response system is closely related to human diseases, because it is essential for the maintenance of homeostasis. Given the significant role of the hypoxia response system in human health, therapeutic applications targeting prolyl hydroxylase-hypoxia-inducible factor (HIF) signaling have been attempted. Thus, systemically reviewing the hypoxia response-based therapeutic strategies is of great significance. Recent Advances: Disturbance of the hypoxia response is a characteristic feature of various diseases. Targeting the hypoxia response system is, thus, a promising therapeutic strategy. Interestingly, several compounds and drugs are currently under clinical trials, and some have already been approved for use in the treatment of certain human diseases. Critical Issues: We summarize the molecular mechanisms of the hypoxia response system and address the potential therapeutic implications in kidney diseases. Given that the effects of hypoxia response in kidney diseases are likely to depend on the pathological context, specific cell types, and the differences in the activation pattern of HIF isoforms, the precise application is critical for the treatment of kidney diseases. Although HIF-PHIs (HIF-PHD inhibitors) have been proven to be effective and well tolerated in chronic kidney disease patients with anemia, the potential on-target consequence of HIF activation and some outstanding questions warrant further consideration. Future Direction: The mechanism of the hypoxia response system disturbance remains unclear. Elucidation of the molecular mechanism of hypoxia response and its precise effects on kidney diseases warrants clarification. Considering the complexity of the hypoxia response system and multiple biological processes controlled by HIF signaling, the development of more specific inhibitors is highly warranted. Antioxid. Redox Signal. 37, 936-955.

Suppression of PFKFB3-driven glycolysis restrains endothelial-to-mesenchymal transition and fibrotic response

Endothelial-to-mesenchymal transition (EndoMT), the process wherein endothelial cells lose endothelial identity and adopt mesenchymal-like phenotypes, constitutes a critical contributor to cardiac fibrosis. The phenotypic plasticity of endothelial cells can be intricately shaped by alteration of metabolic pathways, but how endothelial cells adjust cellular metabolism to drive EndoMT is incompletely understood. Here, we identified 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) as a critical driver of EndoMT via triggering abnormal glycolysis and compromising mitochondrial respiration. Pharmacological suppression of PFKFB3 with salvianolic acid C (SAC), a phenolic compound derived from Salvia miltiorrhiza, attenuates EndoMT and fibrotic response. PFKFB3-haplodeficiency recapitulates the anti-EndoMT effect of SAC while PFKFB3-overexpression augments the magnitude of EndoMT and exacerbates cardiac fibrosis. Mechanistically, PFKFB3-driven glycolysis compromises cytoplasmic nicotinamide adenine dinucleotide phosphate (reduced form, NADPH) production via hijacking glucose flux from pentose phosphate pathway. Efflux of mitochondrial NADPH through isocitrate/α-ketoglutarate shuttle replenishes cytoplasmic NADPH pool but meanwhile impairs mitochondrial respiration by hampering mitochondrial iron-sulfur cluster biosynthesis. SAC disrupts PFKFB3 stability by accelerating its degradation and thus maintains metabolic homeostasis in endothelial cells, underlying its anti-EndoMT effects. These findings for the first time identify the critical role of PFKFB3 in triggering EndoMT by driving abnormal glycolysis in endothelial cells, and also highlight the therapeutic potential for pharmacological intervention of PFKFB3 (with SAC or other PFKFB3 inhibitors) to combat EndoMT-associated fibrotic responses via metabolic regulation.

Screening of prolyl hydroxylase 2 inhibitors based on quantitative strategy of peptides

Prolyl hydroxylase 2 (PHD2) is a key oxygen receptor regulating oxygen homeostasis in human body, and it is one of the important targets for drug research and development of hypoxia related diseases. In PHD2 enzymatic reaction, the structure of substrate (HIF-1α^556-574) and product (hydroxylated HIF-1α) peptide only differ from one oxygen atom (MW>2000), which makes it a great challenge to separate them accurately and efficiently. In this work, the direct separation and detection of HIF-1α and hydroxylated HIF-1α has been firstly reported based on micellar electrokinetic chromatography (MEKC). Under optimized conditions, the intraday RSD of peak area and apparent electrophoretic mobility of hydroxylated HIF-1α were 1.87% and 0.81% respectively, and the interday RSD were 2.01% and 1.03% respectively. The LOD and LOQ of the MEKC method were 10 µM and 50 µM respectively, and the recoveries was 98.42-105.38%. Subsequently, the feasibility and accuracy of MEKC method to screen PHD2 inhibitors were confirmed by using roxadustat, and the IC₅₀ (10.36 µM) and inhibitor type (competitive) were consistent with literature. Finally, the method was used to screen the PHD2 inhibitory activity of five traditional Chinese medicines (TCMs). The present work not only overcomes the difficulties of direct quantitative detection of hydroxylated HIF-1α, but also provides technical support for exploring and discovering new drug leads for hypoxia-related diseases from complex matrix such as TCMs.

Potential Role of APEX1 During Ferroptosis

Ferroptosis is a recently discovered category of programmed cell death. It is much different from other types of cell death such as apoptosis, necrosis and autophagy. The main pathological feature of ferroptosis is the accumulation of iron-dependent lipid peroxidation. The typical changes in the morphological features of ferroptosis include cell volume shrinkage and increased mitochondrial membrane area. The mechanisms of ferroptosis may be mainly related to lipid peroxidation accumulation, imbalance in amino acid antioxidant system, and disturbance of iron metabolism. Besides, hypoxia-inducible factor (HIF), nuclear factor-E2-related factor 2 (Nrf2), and p53 pathway have been demonstrated to be involved in ferroptosis. At present, the molecular mechanisms of ferroptosis pathway are still unmapped. In this review, an outlook has been put forward about the crucial role of apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) in the regulation of ferroptosis. APEX1 plays an important role in the regulation of intracellular redox balance and can be used as a potential inhibitor of ferroptotic cell death. Bioinformatics analysis indicated that the mRNA level of APEX1 is decreased in cases of ferroptosis triggered by erastin. Besides, it was found that there was a significant correlation between APEX1 and genes in the ferroptosis pathway. We have discussed the possibility to employ APEX1 inducers or inhibitors in the regulation of ferroptosis as a new strategy for the treatment of various human diseases.

The effect of adaptation to hypoxia on cardiac tolerance to ischemia/reperfusion

The acute myocardial infarction (AMI) and sudden cardiac death (SCD), both associated with acute cardiac ischemia, are one of the leading causes of adult death in economically developed countries. The development of new approaches for the treatment and prevention of AMI and SCD remains the highest priority for medicine. A study on the cardiovascular effects of chronic hypoxia (CH) may contribute to the development of these methods. Chronic hypoxia exerts both positive and adverse effects. The positive effects are the infarct-reducing, vasoprotective, and antiarrhythmic effects, which can lead to the improvement of cardiac contractility in reperfusion. The adverse effects are pulmonary hypertension and right ventricular hypertrophy. This review presents a comprehensive overview of how CH enhances cardiac tolerance to ischemia/reperfusion. It is an in-depth analysis of the published data on the underlying mechanisms, which can lead to future development of the cardioprotective effect of CH. A better understanding of the CH-activated protective signaling pathways may contribute to new therapeutic approaches in an increase of cardiac tolerance to ischemia/reperfusion.

Isosteviol improves cardiac function and promotes angiogenesis after myocardial infarction in rats

Isosteviol has been indicated as a cardiomyocyte protector. However, the underlying mechanism remains unclear. Thus, we sought to confirm the protective effect of isosteviol after myocardial infarction in a model of permanent coronary artery occlusion and investigate the potential proangiogenic activity in vitro and in vivo. A 4-week permanent coronary artery occlusion rat model was generated, and the protective effect of isosteviol was evaluated by echocardiographic imaging and hemodynamics assays. The coronary capillary density was tested by immunochemistry and micro-computed tomography (μCT) imaging. The effect of isosteviol on endothelial cells was determined in human umbilical vein endothelial cells (HUVECs) in vitro and Tg (kdrl: EGFP) zebrafish in vivo. We also examined the expression of related transcription factors by real-time polymerase chain reaction (RT-qPCR). Isosteviol increased ejection fraction (EF), fractional shortening (FS), cardiac systolic index (CI), maximum rate of increase of left ventricular pressure (Max dp/dt), and left ventricular systolic pressure (LVSP) by 32%, 40%, 25%, 26%, and 10%, respectively, in permanent coronary artery occlusion rats. Interestingly, it also promoted coronary capillary density by 2.5-fold. In addition, isosteviol promoted the proliferation and branching of HUVECs in vitro. It also rescued intersegmental vessel (ISV) development and improved endothelial cell proliferation by approximately fivefold (4-6) in zebrafish embryos in vivo. Isosteviol also upregulated the expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGFA) in zebrafish by fourfold and 3.5-fold, respectively. Our findings suggest that isosteviol is a proangiogenic agent and that this activity is related to its protective effects against myocardial ischemia. After using the permanent coronary artery occlusion model, we demonstrated that isosteviol promotes angiogenesis directly and increases capillary density in myocardial ischemia rats. Isosteviol promotes angiogenesis in zebrafish in vivo and increases vascular endothelial cell proliferation in HUVECs and zebrafish. The angiogenesis activity of isosteviol may be correlated with VEGFA and HIF-1α signaling.

Antioxidant Effects of Protocatechuic Acid and Protocatechuic Aldehyde: Old Wine in a New Bottle

Phenolic compounds are naturally present as secondary metabolites in plant-based sources such as fruits, vegetables, and spices. They have received considerable attention for their antioxidant, anti-inflammatory, and anti-carcinogenic properties for protection against many chronic disorders such as neurodegenerative diseases, diabetes, cardiovascular diseases, and cancer. They are categorized into various groups based on their chemical structure and include phenolic acids, flavonoids, curcumins, tannins, and quinolones. Their structural variations contribute to their specific beneficial effects on human health. The antioxidant property of phenolic compounds protects against oxidative stress by up-regulation of endogenous antioxidants, scavenging free radicals, and anti-apoptotic activity. Protocatechuic acid (PCA; 3,4-dihydroxy benzoic acid) and protocatechuic aldehyde (PAL; 3,4-dihydroxybenzaldehyde) are naturally occurring polyphenols found in vegetables, fruits, and herbs. PCA and PAL are the primary metabolites of anthocyanins and proanthocyanidins, which have been shown to possess pharmacological actions including antioxidant activity in vitro and in vivo. This review aims to explore the therapeutic potential of PCA and PAL by comprehensively summarizing their pharmacological properties reported to date, with an emphasis on their mechanisms of action and biological properties.

Protocatechuic aldehyde protects cardiomycoytes against ischemic injury via regulation of nuclear pyruvate kinase M2

Rescuing cells from stress damage emerges a potential therapeutic strategy to combat myocardial infarction. Protocatechuic aldehyde (PCA) is a major phenolic acid in Chinese herb Danshen (Salvia miltiorrhiza root). This study investigated whether PCA regulated nuclear pyruvate kinase isoform M2 (PKM2) function to protect cardiomyocytes. In rats subjected to isoprenaline, PCA attenuated heart injury and protected cardiomyocytes from apoptosis. Through DARTS and CETSA assays, we identified that PCA bound and promoted PKM2 nuclear translocation in cardiomyocytes exposed to oxygen/glucose deprivation (OGD). In the nucleus, PCA increased the binding of PKM2 to β-catenin via preserving PKM2 acetylation, and the complex, in cooperation with T-cell factor 4 (TCF4), was required for transcriptional induction of genes encoding anti-apoptotic proteins, contributing to rescuing cardiomyocyte survival. In addition, PCA ameliorated mitochondrial dysfunction and prevented mitochondrial apoptosis dependent on PKM2. Consistently, PCA increased the binding of PKM2 to β-catenin, improved heart contractive function, normalized heart structure and attenuated oxidative damage in mice subjected to artery ligation, but the protective effects were lost in Pkm2-deficient heart. Together, we showed that PCA regulated nuclear PKM2 function to rescue cardiomyocyte survival via β-catenin/TCF4 signaling cascade, suggesting the potential of pharmacological intervention of PKM2 shuttle to protect the heart.

Novel Co-crystal of Pentoxifylline and Protocatechuic Acid Relieves Allodynia in Rat Models of Peripheral Neuropathic Pain and CRPS by Alleviating Local Tissue Hypoxia

Local tissue ischemic hypoxia is a peripheral process that can be targeted with topical treatment to alleviate pain under chronic pain conditions such as complex regional pain syndrome (CRPS) and peripheral neuropathic pain. We recently reported three novel salts and a co-crystal composed of vasoactive agents and antioxidant nutraceuticals, all of which produced potent topical anti-allodynic effects in the chronic postischemic pain (CPIP) rat model of CRPS. One of the products, pentx-pca, is a co-crystal synthesized from pentoxifylline (pentx) and protocatechuic acid (pca). Pentx-pca exhibited potent topical anti-allodynic effects in CPIP and rats with chronic constriction injury of the sciatic nerve exceeding effects produced individually by pentx and pca. We hypothesized that the anti-allodynic effects of pentx-pca in CPIP rats were due to its impact on local tissue oxygenation and subsequent oxygen-dependent mitochondrial respiration. Percutaneous tissue oxygen saturation (SaO₂) measurements taken from the hind paw of the CPIP rats revealed that anti-allodynic doses of topical pentx-pca increased local tissue SaO₂. Moreover, assessment of the oxygen-dependent mitochondrial function using a triphenyl tetrazolium chloride assay revealed that mitochondrial dysfunction significantly declined in the plantar muscle collected from CPIP rats topically treated with anti-allodynic doses of pentx-pca as compared to vehicle-treated CPIP rats. Furthermore, time-dependent resolution of plantar muscle mitochondrial dysfunction, that occurred in the CPIP rats at 6-week post procedure, paralleled the loss of the anti-allodynic response to topical treatment with pentx-pca. Our results indicated that pentx-pca produced potent anti-allodynic effects in the CPIP rat model of CRPS by alleviating peripheral tissue ischemia/hypoxia and downstream hypoxia-driven mitochondrial dysfunction.

STAT3-mediated activation of mitochondrial pathway contributes to antitumor effect of dihydrotanshinone I in esophageal squamous cell carcinoma cells

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies with a poor prognosis, and its treatment remains a great challenge. Dihydrotanshinone I (DHTS) has been reported to exert antitumor effect in many cancers. However, the role of DHTS in ESCC remains unclear.

AIM

To investigate the antitumor effect of DHTS in ESCC and the underlying mechanisms.

METHODS

CCK-8 assay and cell cycle analysis were used to detect proliferation and cell cycle in ESCC cells. Annexin V-PE/7-AAD double staining assay and Hoechst 33258 staining were used to detect apoptosis in ESCC cells. Western blot was used to detect the expression of proteins associated with the mitochondrial pathway. Immunofluorescence was used to detect the expression of phosphorylated STAT3 (pSTAT3) in DHTS-treated ESCC cells. ESCC cells with STAT3 knockdown and overexpression were constructed to verify the role of STAT3 in DHTS induced apoptosis. A xenograft tumor model in nude mice was used to evaluate the antitumor effect of DHTS in vivo.

RESULTS

After treatment with DHTS, the proliferation of ESCC cells was inhibited in a dose- and time-dependent manner. Moreover, DHTS induced cell cycle arrest in the G0/1 phase. Annexin V-PE/7-AAD double staining assay and Hoechst 33258 staining revealed that DHTS induced obvious apoptosis in KYSE30 and Eca109 cells. At the molecular level, DHTS treatment reduced the expression of pSTAT3 and anti-apoptotic proteins, while increasing the expression of pro-apoptotic proteins in ESCC cells. STAT3 knockdown in ESCC cells markedly promoted the activation of the mitochondrial pathway while STAT3 overexpression blocked the activation of the mitochondrial pathway. Additionally, DHTS inhibited tumor cell proliferation and induced apoptosis in a xenograft tumor mouse model.

CONCLUSION

DHTS exerts antitumor effect in ESCC via STAT3-mediated activation of the mitochondrial pathway. DHTS may be a novel therapeutic agent for ESCC.

Combination of natural antivirals and potent immune invigorators: A natural remedy to combat COVID-19

The flare‐up in severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) that emerged in December 2019 in Wuhan, China, and spread expeditiously worldwide has become a health challenge globally. The rapid transmission, absence of anti‐SARS‐CoV‐2 drugs, and inexistence of vaccine are further exacerbating the situation. Several drugs, including chloroquine, remdesivir, and favipiravir, are presently undergoing clinical investigation to further scrutinize their effectiveness and validity in the management of COVID‐19. Natural products (NPs) in general, and plants constituents specifically, are unique sources for various effective and novel drugs. Immunostimulants, including vitamins, iron, zinc, chrysin, caffeic acid, and gallic acid, act as potent weapons against COVID‐19 by reinvigorating the defensive mechanisms of the immune system. Immunity boosters prevent COVID‐19 by stimulating the proliferation of T‐cells, B‐cells, and neutrophils, neutralizing the free radicals, inhibiting the immunosuppressive agents, and promoting cytokine production. Presently, antiviral therapy includes several lead compounds, such as baicalin, glycyrrhizin, theaflavin, and herbacetin, all of which seem to act against SARS‐CoV‐2 via particular targets, such as blocking virus entry, attachment to host cell receptor, inhibiting viral replication, and assembly and release.

JMJD5 attenuates oxygen-glucose deprivation and reperfusion-induced injury in cardiomyocytes through regulation of HIF-1α-BNIP3

Proteins in Jumonji family function as histone demethylases and participate in cardiac development. Jumonji domain containing 5 (JMJD5) is responsible for the embryonic development through removing methyl moieties from H3K36me2 histone, and has pro-proliferative effect on heart and eye development. However, the protective role of JMJD5 against oxygen-glucose deprivation and reperfusion (OGD/R)-induced injury in cardiomyocytes has not been fully understood. Firstly, myocardial ischemia/reperfusion (I/R) rat model was established by ligation of left coronary artery. OGD/R was performed in non-transfected H9C2 or H9C2 transfected with pcDNA-JMJD5 plasmid to induce cell cytotoxicity. Data from qRT-PCR and western blot showed that JMJD5 was reduced in the heart tissues of myocardial I/R rat model and OGD/R-induced H9C2. Secondly, JMJD5 over-expression attenuated OGD/R-induced decrease in cell viability and increase in lactate dehydrogenase secretion and cell apoptosis in H9C2. Mitophagy was promoted by pcDNA-mediated over-expression of JMJD5 with enhanced protein expression of LC3-I, LC3-II, Atg5, and Beclin 1. Thirdly, knockdown of JMJD5 aggravated OGD/R-induced decrease in hypoxia-inducible factor-1α (HIF-1α), whereas JMJD5 over-expression enhanced BNIP3 (Bcl-2/adenovirus E1B 19-kDa interacting protein) through upregulation of HIF-1α. Lastly, BNIP3 silencing promoted cell apoptosis, suppressed mitophagy, and attenuated the protective effects of JMJD5 over-expression against OGD/R-induced injury in H9C2. In conclusion, JMJD5 exerted protective effects against OGD/R-induced injury in cardiomyocytes through upregulation of HIF-1α-BNIP3.

Calpain-Mediated Mitochondrial Damage: An Emerging Mechanism Contributing to Cardiac Disease

Calpains belong to the family of calcium-dependent cysteine proteases expressed ubiquitously in mammals and many other organisms. Activation of calpain is observed in diseased hearts and is implicated in cardiac cell death, hypertrophy, fibrosis, and inflammation. However, the underlying mechanisms remain incompletely understood. Recent studies have revealed that calpains target and impair mitochondria in cardiac disease. The objective of this review is to discuss the role of calpains in mediating mitochondrial damage and the underlying mechanisms, and to evaluate whether targeted inhibition of mitochondrial calpain is a potential strategy in treating cardiac disease. We expect to describe the wealth of new evidence surrounding calpain-mediated mitochondrial damage to facilitate future mechanistic studies and therapy development for cardiac disease.

KCNQ1OT1 Exacerbates Ischemia-Reperfusion Injury Through Targeted Inhibition of miR-140-3P

Potassium voltage-gated channel subfamily Q member 1 opposite strand 1 (KCNQ1OT1), a long non-coding RNA found in the KCNQ1 locus, has been evidenced to play important roles in the aggravation of inflammatory and oxidative stresses under hypoxia, but whether and how KCNQ1OT1 contributes to neuronal damages in the cerebral ischemic stroke remains unknown. In the present study, we found a dominant upregulation of KCNQ1OT1 both in the plasma of cerebral ischemia patients and in an oxygen-glucose deprivation and reperfusion (OGD/R) model in PC12 cells. KCNQ1OT1 knocking-down significantly ameliorated the inflammation, oxidative stress, and cell apoptosis induced by OGD/R. We further demonstrated that KCNQ1OT1 directly bound to and suppressed the expression of miR-140-3p. Overexpressing miR-140-3p significantly alleviated both the inflammation, oxidative stress, and cell apoptosis in OGD/R, while all those cytoprotective effects of miR-140-3p-overexpression were hindered by the co-overexpression of KCNQ1OT1. Furthermore, we found a direct interaction between miR-140-3p and the hypoxia-inducible factor-1α (HIF-1α), which was suppressed by the upregulation of KCNQ1OT1 in OGD/R. Our results indicate that KCNQ1OT1 exacerbates cerebral ischemia-reperfusion injury by targeted binding to miR-140-3p, thus interfering its direct interaction with HIF-1α. These data provide novel therapeutic targets in the cerebral ischemic stroke.

Impact of High Altitude on Cardiovascular Health: Current Perspectives

Globally, about 400 million people reside at terrestrial altitudes above 1500 m, and more than 100 million lowlanders visit mountainous areas above 2500 m annually. The interactions between the low barometric pressure and partial pressure of O2, climate, individual genetic, lifestyle and socio-economic factors, as well as adaptation and acclimatization processes at high elevations are extremely complex. It is challenging to decipher the effects of these myriad factors on the cardiovascular health in high altitude residents, and even more so in those ascending to high altitudes with or without preexisting diseases. This review aims to interpret epidemiological observations in high-altitude populations; present and discuss cardiovascular responses to acute and subacute high-altitude exposure in general and more specifically in people with preexisting cardiovascular diseases; the relations between cardiovascular pathologies and neurodegenerative diseases at altitude; the effects of high-altitude exercise; and the putative cardioprotective mechanisms of hypobaric hypoxia.

Polyphenolic-Rich Compounds From Dillenia pentagyna (Roxb.) Attenuates the Doxorubicin-Induced Cardiotoxicity: A High-Frequency Ultrasonography Assisted Approach

Cardiovascular complications are the foremost concern in patients undergoing anticancer therapy. There is an unmet need to address the problems arising from the drug-induced toxicity for the long-term benefit of the patients undergoing chemotherapy. Alternative medicines are gaining their prosperity in addressing the various drug-induced organ toxicity. Dillenia pentagyna Roxb (DP) is an ethnomedicinal plant rich in flavonoids and phenolic contents. In India & Nepal, DP is a common ingredient of traditional medicines used to treat multiple ailments like inflammation, cancer, and diabetes. However, its protective role against doxorubicin (Dox) induced cardiotoxicity remains unexplored. Herein, we investigated the potential effects of various extracts/fractions obtained from the DP’s bark against Dox-induced cardiotoxicity, both in-vitro and in-vivo. The anti-oxidant content of the extracts/fractions was evaluated by using DPPH, ABTS and FRAP chemical assays. The results indicated that the hydroalcoholic (HA) extract of DP has intense anti-oxidant potential. Further fractionation of DP revealed that the phenolic-rich fraction (F1) has a high anti-oxidant potential. The protective effect of extract/fraction was also investigated in the H9c2 cell line following the Dox-induced cardiotoxicity model. We observed that the pre-treatment of extract/fraction in cardiomyocytes had exhibited increased cell viability. Fluorescence-based chemical assays indicated a decreased ROS levels in the treated groups in comparison to the Dox control group. The effect of DP was evaluated further in balb/c mice by the Dox-induced cardiotoxicity model. Non-invasive techniques like high-frequency ultrasonography and electrocardiogram revealed that the mice pre-treated with DP had improved cardiac functionality (left ventricular ejection fraction and stroke volume) and normalized the electrocardiograms compared to the Dox control group. Further, biochemical analysis with the cardiac tissues revealed that the cytoprotective proteins like HO-1, SOD-2, and Nrf-2 were elevated in the DP treated groups compared to the Dox control group. Overall, our results suggested that the bioactive extract/fractions of DP helped alleviate the Dox-induced cardiotoxicity. LC-QTOF-ESI-MS analysis of DP and F1 indicated that polyphenolic anti-oxidant compounds like gallic acid, syringic acid, and sinapic acid could be responsible for the potent -cardioprotective effect. Future understanding of the pharmacokinetics and pharmacodynamic parameters can help translate from the bench to the bedside.

HIF‑1α in myocardial ischemia‑reperfusion injury (Review)

Myocardial ischemia-reperfusion injury (MIRI) is a severe injury to the ischemic myocardium following the recovery of blood flow. Currently, there is no effective treatment for MIRI in clinical practice. Over the past two decades, biological studies of hypoxia and hypoxia-inducible factor-1α (HIF-1α) have notably improved understanding of oxygen homeostasis. HIF-1α is an oxygen-sensitive transcription factor that mediates adaptive metabolic responses to hypoxia and serves a pivotal role in MIRI. In particular, previous studies have demonstrated that HIF-1α improves mitochondrial function, decreases cellular oxidative stress, activates cardioprotective signaling pathways and downstream protective genes and interacts with non-coding RNAs. The present review summarizes the roles and associated mechanisms of action of HIF-1α in MIRI. In addition, HIF-1α-associated MIRI intervention, including natural compounds, exosomes, ischemic preconditioning and ischemic post-processing are presented. The present review provides evidence for the roles of HIF-1α activation in MIRI and supports its use as a therapeutic target.

Antibacterial Mechanism of Dihydrotanshinone I

The antimicrobial activity and the underlying action mechanisms of dihydrotanshinone I against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamases Staphylococcus aureus were investigated with Kleihauer-Betke (K-B) test. The antibacterial mechanisms of dihydrotanshinone I were investigated by monitoring the changes in electric conductivity, concentration of AKP, protein content, and patterns of protein electrophoretic bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The antibacterial rings showed that antimicrobial activity of dihydrotanshinone I at 18 mM was stronger to Staphylococcus aureus than to methicillin-resistant Staphylococcus aureus and extended-spectrum beta-lactamases Staphylococcus aureus. The minimum inhibitory concentration (MIC) and IC50 values showed that dihydrotanshinone I had the strongest inhibitory activity against S. aureus (MIC = 280 µM, IC50 = 874 ± 0.01 µM, respectively). Dihydrotanshinone I could increase the electric conductivity, concentration of alkaline phosphatase (AKP) and protein content. The patterns of protein bands in SDS-PAGE were changed obviously. Dihydrotanshinone I also significantly inhibited S. aureus, methicillin-resistant S. aureus, and extended-spectrum beta-lactamases S. aureus, indicating that dihydrotanshinone I can damage the structures of cell wall and cell membrane to increase permeability of cell membrane and release of cell components. Dihydrotanshinone I could influence the synthesis of bacterial protein, destroy the protein, or reject the anabolism or expression of the protein, and finally lead to the loss of normal physiological function of bacteria.

HIF in Nephrotoxicity during Cisplatin Chemotherapy: Regulation, Function and Therapeutic Potential

Simple Summary

Cisplatin is a widely used chemotherapy drug, but its use and efficacy are limited by its nephrotoxicity. HIF has protective effects against kidney injury during cisplatin chemotherapy, but it may attenuate the anti-cancer effect of cisplatin. In this review, we describe the role and regulation of HIF in cisplatin-induced nephrotoxicity and highlight the therapeutic potential of targeting HIF in chemotherapy.

Abstract

Cisplatin is a highly effective, broad-spectrum chemotherapeutic drug, yet its clinical use and efficacy are limited by its side effects. Particularly, cancer patients receiving cisplatin chemotherapy have high incidence of kidney problems. Hypoxia-inducible factor (HIF) is the “master” transcription factor that is induced under hypoxia to trans-activate various genes for adaptation to the low oxygen condition. Numerous studies have reported that HIF activation protects against AKI and promotes kidney recovery in experimental models of cisplatin-induced acute kidney injury (AKI). In contrast, little is known about the effects of HIF on chronic kidney problems following cisplatin chemotherapy. Prolyl hydroxylase (PHD) inhibitors are potent HIF inducers that recently entered clinical use. By inducing HIF, PHD inhibitors may protect kidneys during cisplatin chemotherapy. However, HIF activation by PHD inhibitors may reduce the anti-cancer effect of cisplatin in tumors. Future studies should test PHD inhibitors in tumor-bearing animal models to verify their effects in kidneys and tumors.

Activated PKB/GSK-3β synergizes with PKC-δ signaling in attenuating myocardial ischemia/reperfusion injury via potentiation of NRF2 activity: Therapeutic efficacy of dihydrotanshinone-I

Disrupted redox status primarily contributes to myocardial ischemia/reperfusion injury (MIRI). NRF2, the endogenous antioxidant regulator, might provide therapeutic benefits. Dihydrotanshinone-I (DT) is an active component in Salvia miltiorrhiza with NRF2 induction potency. This study seeks to validate functional links between NRF2 and cardioprotection of DT and to investigate the molecular mechanism particularly emphasizing on NRF2 cytoplasmic/nuclear translocation. DT potently induced NRF2 nuclear accumulation, ameliorating post-reperfusion injuries via redox alterations. Abrogated cardioprotection in NRF2-deficient mice and cardiomyocytes strongly supports NRF2-dependent cardioprotection of DT. Mechanistically, DT phosphorylated NRF2 at Ser40, rendering its nuclear-import by dissociating from KEAP1 and inhibiting degradation. Importantly, we identified PKC-δ-(Thr505) phosphorylation as primary upstream event triggering NRF2-(Ser40) phosphorylation. Knockdown of PKC-δ dramatically retained NRF2 in cytoplasm, convincing its pivotal role in mediating NRF2 nuclear-import. NRF2 activity was further enhanced by activated PKB/GSK-3β signaling via nuclear-export signal blockage independent of PKC-δ activation. By demonstrating independent modulation of PKC-δ and PKB/GSK-3β/Fyn signaling, we highlight the ability of DT to exploit both nuclear import and export regulation of NRF2 in treating reperfusion injury harboring redox homeostasis alterations. Coactivation of PKC and PKB phenocopied cardioprotection of DT in vitro and in vivo, further supporting the potential applicability of this rationale.

Pretreatment with Roxadustat (FG-4592) Attenuates Folic Acid-Induced Kidney Injury through Antiferroptosis via Akt/GSK-3β/Nrf2 Pathway

Folic acid- (FA-) induced kidney injury is characterized by the tubule damage due to the disturbance of the antioxidant system and subsequent interstitial fibrosis. FG-4592 is an inhibitor of prolyl hydroxylase of hypoxia-inducible factor (HIF), an antioxidant factor. The present study investigated the protective role of FG-4592 pretreatment at the early stage of the kidney injury and long-term impact on the progression of renal fibrosis. FG-4592 was administrated two days before FA injection in mice. On the second day after FA injection, the mice with FG-4592 pretreatment showed an improved renal function, compared with those without FG-4592 pretreatment, indicated by biochemical and histological parameters; meanwhile, the cellular content of iron, malondialdehyde, and 4-hydroxynonenal histologically decreased, implying the suppression of iron accumulation and lipid peroxidation. Simultaneously, upregulation of HIF-1α was found, along with Nrf2 activation, which was reflected by increased nuclear translocation and high-expression of downstream proteins, including heme-oxygenase1, glutathione peroxidase4, and cystine/glutamate transporter, as well as ferroportin. Correspondingly, the elevated levels of antioxidative enzymes and glutathione, as well as reduced iron accumulation, were observed, suggesting a lower risk of occurrence of ferroptosis with FG-4592 pretreatment. This was confirmed by reversed pathological parameters and improved renal function in FA-treated mice with the administration of ferrostatin-1, a specific ferroptosis inhibitor. Furthermore, a signal pathway study indicated that Nrf2 activation was associated with increased phosphorylation of Akt and GSK-3β, verified by the use of an inhibitor of the PI3K that phosphorylates Akt. Moreover, FG-4592 pretreatment also decreased macrophage infiltration and expression of inflammatory factors TNF-α and IL-1β. On the 14^th day after FA injection, FG-4592 pretreatment decreased collagen deposition and expression of fibrosis biomarkers. These findings suggest that the protective role of FG-4592 pretreatment is achieved mainly by decreasing ferroptosis at the early stage of FA-induced kidney injury via Akt/GSK-3β-mediated Nrf2 activation, which retards the fibrosis progression.

Pharmacological properties of tanshinones, the natural products from Salvia miltiorrhiza

Danshen (Cai, et al. 2016) is the dry root and rhizome of the herbaceous plant Salvia miltiorrhiza Bge. of family labiatae, a perennial plant that is native to China and Japan. The primary modern clinical applications of Danshen are for heart disease, chronic hepatitis, early cirrhosis, cerebral ischemia and pulmonary heart disease. Emerging evidence from cellular, animal, and clinical studies has begun to illuminate the pharmacological attributes of the primary lipophilic tanshinones from Danshen, which include tanshinone I, tanshinone II, cryptotanshinone and dihydrotanshinone, etc. Tanshinones offer the properties of anti-oxidation, anti-inflammation, antitumor, phytoestrogenic activity, vasodilation, neuroprotection, regulate metabolic function and other pharmacological advances. This chapter will review the discovery of the pharmacodynamic mechanism and pharmacokinetic studies of tanshinones and Danshen for further clinical applications.