Icariin protects cardiomyocytes against ischaemia/reperfusion injury by attenuating sirtuin 1-dependent mitochondrial oxidative damage

Ghrelin alleviates intestinal ischemia-reperfusion injury by activating the GHSR-1α/Sirt1/FOXO1 pathway

Ischemia-reperfusion (IR) injury is primarily characterized by the restoration of blood flow perfusion and oxygen supply to ischemic tissue and organs, but it paradoxically leads to tissue injury aggravation. IR injury is a challenging pathophysiological process that is difficult to avoid clinically and frequently occurs during organ transplantation, surgery, shock resuscitation, and other processes. The major causes of IR injury include increased levels of free radicals, calcium overload, oxidative stress, and excessive inflammatory response. Ghrelin is a newly discovered brain-intestinal peptide with anti-inflammatory and antiapoptotic effects that improve blood supply. The role and mechanism of ghrelin in intestinal ischemia-reperfusion (IIR) injury remain unclear. We hypothesized that ghrelin could attenuate IIR-induced oxidative stress and apoptosis. To investigate this, we established IIR by using a non-invasive arterial clip to clamp the root of the superior mesenteric artery (SMA) in mice. Ghrelin was injected intraperitoneally at a dose of 50 μg/kg 20 min before IIR surgery, and [D-Lys3]-GHRP-6 was injected intraperitoneally at a dose of 12 nmol/kg 20 min before ghrelin injection. We mimicked the IIR process with hypoxia-reoxygenation (HR) in Caco-2 cells, which are similar to intestinal epithelial cells in structure and biochemistry. Our results showed that ghrelin inhibited IIR/HR-induced oxidative stress and apoptosis by activating GHSR-1α. Moreover, it was found that ghrelin activated the GHSR-1α/Sirt1/FOXO1 signaling pathway. We further inhibited Sirt1 and found that Sirt1 was critical for ghrelin-mediated mitigation of IIR/HR injury. Overall, our data suggest that pretreatment with ghrelin reduces oxidative stress and apoptosis to attenuate IIR/HR injury by binding with GHSR-1α to further activate Sirt1.

Icariin alleviates renal inflammation and tubulointerstitial fibrosis via Nrf2-mediated attenuation of mitochondrial damage

Tubulointerstitial fibrosis is an inevitable consequence of all progressive chronic kidney disease (CKD) and contributes to a substantial health burden worldwide. Icariin, an active flavonoid glycoside obtained from Epimedium species, exerts potential antifibrotic effect. The study aimed to explore the protective effects of icariin against tubulointerstitial fibrosis in unilateral ureteral obstruction (UUO)-induced CKD mice and TGF-β1-treated HK-2 cells, and furthermore, to elucidate the underlying mechanisms. The results demonstrated that icariin significantly improved renal function, alleviated tubular injuries, and reduced fibrotic lesions in UUO mice. Furthermore, icariin suppressed renal inflammation, reduced oxidative stress as evidenced by elevated superoxide dismutase activity and decreased malondialdehyde level. Additionally, TOMM20 immunofluorescence staining and transmission electron microscope revealed that mitochondrial mass and morphology of tubular epithelial cells in UUO mice was restored by icariin. In HK-2 cells treated with TGF-β1, icariin markedly decreased profibrotic proteins expression, inhibited inflammatory factors, and protected mitochondria along with preserving mitochondrial morphology, reducing reactive oxygen species (ROS) and mitochondrial ROS (mtROS) overproduction, and preserving membrane potential. Further investigations demonstrated that icariin could activate nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway both in vivo and in vitro, whereas inhibition of Nrf2 by ML385 counteracted the protective effects of icariin on TGF-β1-induced HK-2 cells. In conclusion, icariin protects against renal inflammation and tubulointerstitial fibrosis at least partly through Nrf2-mediated attenuation of mitochondrial dysfunction, which suggests that icariin could be developed as a promising therapeutic candidate for the treatment of CKD.

Roles of flavonoids in ischemic heart disease: Cardioprotective effects and mechanisms against myocardial ischemia and reperfusion injury

BACKGROUND

Flavonoids are extensively present in fruits, vegetables, grains, and medicinal plants. Myocardial ischemia and reperfusion (MI/R) comprise a sequence of detrimental incidents following myocardial ischemia. Research indicates that flavonoids have the potential to act as cardioprotective agents against MI/R injuries. Several specific flavonoids, e.g., luteolin, hesperidin, quercetin, kaempferol, and puerarin, have demonstrated cardioprotective activities in animal models.

PURPOSE

The objective of this review is to identify the cardioprotective flavonoids, investigate their mechanisms of action, and explore their application in myocardial ischemia.

METHODS

A search of PubMed database and Google Scholar was conducted using keywords "myocardial ischemia" and "flavonoids". Studies published within the last 10 years reporting on the cardioprotective effects of natural flavonoids on animal models were analyzed.

RESULTS

A total of 55 natural flavonoids were identified and discussed within this review. It can be summarized that flavonoids regulate the following main strategies: antioxidation, anti-inflammation, calcium modulation, mitochondrial protection, ER stress inhibition, anti-apoptosis, ferroptosis inhibition, autophagy modulation, and inhibition of adverse cardiac remodeling. Additionally, the number and position of OH, 3'4'-catechol, C2=C3, and C4=O may play a significant role in the cardioprotective activity of flavonoids.

CONCLUSION

This review serves as a reference for designing a daily diet to prevent or reduce damages following ischemia and screening of flavonoids for clinical application.

The potential of herbal drugs to treat heart failure: The roles of Sirt1/AMPK

Heart failure (HF) is a highly morbid syndrome that seriously affects the physical and mental health of patients and generates an enormous socio-economic burden. In addition to cardiac myocyte oxidative stress and apoptosis, which are considered mechanisms for the development of HF, alterations in cardiac energy metabolism and pathological autophagy also contribute to cardiac abnormalities and ultimately HF. Silent information regulator 1 (Sirt1) and adenosine monophosphate-activated protein kinase (AMPK) are nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases and phosphorylated kinases, respectively. They play similar roles in regulating some pathological processes of the heart through regulating targets such as peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), protein 38 mitogen-activated protein kinase (p38 MAPK), peroxisome proliferator-activated receptors (PPARs), and mammalian target of rapamycin (mTOR). We summarized the synergistic effects of Sirt1 and AMPK in the heart, and listed the traditional Chinese medicine (TCM) that exhibit cardioprotective properties by modulating the Sirt1/AMPK pathway, to provide a basis for the development of Sirt1/AMPK activators or inhibitors for the treatment of HF and other cardiovascular diseases (CVDs).

Wu-zhu-yu Decoction reduces early brain injury following subarachnoid hemorrhage in vivo and in vitro by activating the Nrf2 antioxidant system via SIRT6 targeting

ETHNOPHARMACOLOGICAL RELEVANCE

Early brain damage (EBI) following subarachnoid hemorrhage (SAH) is a long-lasting condition with a high occurrence. However, treatment options are restricted. Wu-zhu-yu Decoction (WZYD) can treat headaches and vomiting, which are similar to the early symptoms of subarachnoid hemorrhage (SAH). However, it is yet unknown if WZYD can reduce EBI following SAH and its underlying mechanisms.

AIM OF THE STUDY

This study aimed to investigate whether WZYD protects against EBI following SAH by inhibiting oxidative stress through activating nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling via Sirtuin 6 (SIRT6)-mediated histone H3 lysine 56 (H3K56) deacetylation.

MATERIALS AND METHODS

In the current investigation, the principal components of WZYD were identified using high-performance liquid chromatography-diode array detection (HPLC-DAD). The SAH model in rats using the internal carotid artery plug puncture approach and the SAH model in primary neurons using hemoglobin incubation were developed. WZYD with different doses (137 mg kg-1, 274 mg kg-1, 548 mg kg-1) and the positive drug-Nimodipine (40 mg kg-1) were intragastrically administered in SAH model rats, respectively. The PC12 cells were cultured with corresponding medicated for 24h. In our investigation, neurological scores, brain water content, Evans blue leakage, Nissl staining, TUNEL staining, oxidative stress, expression of apoptosis-related proteins, and Nrf2/HO-1 signaling were evaluated. The interaction between SIRT6 and Nrf2 was detected by co-immunoprecipitation. SIRT6 knockdown was used to confirm its role in WZYD's neuroprotection.

RESULTS

The WZYD treatment dramatically reduced cerebral hemorrhage and edema, and enhanced neurological results in EBI following SAH rats. WZYD administration inhibited neuronal apoptosis via reducing the expression levels of Cleaved cysteinyl aspartate specific proteinase-3(Cleaved Caspase-3), cysteinyl aspartate specific proteinase-3(caspase-3), and Bcl-2, Associated X Protein (Bax) and increasing the expression of B-cell lymphoma-2(Bal2). It also decreased reactive oxygen species and malondialdehyde levels and increased Nrf2 and HO-1 expression in the rat brain after SAH. In vitro, WZYD attenuated hemoglobin-induced cytotoxicity, oxidative stress and apoptosis in primary neurons. Mechanistically, WZYD enhanced SIRT6 expression and H3K56 deacetylation, activated Nrf2/HO-1 signaling, and promoted the interaction between SIRT6 and Nrf2. Knockdown of SIRT6 abolished WZYD-induced neuroprotection.

CONCLUSIONS

WZYD attenuates EBI after SAH by activating Nrf2/HO-1 signaling through SIRT6-mediated H3K56 deacetylation, suggesting its therapeutic potential for SAH treatment.

Icariin improves cardiac function and remodeling via the TGF-β1/Smad signaling pathway in rats following myocardial infarction

BACKGROUND

Postinfarction cardiac remodeling presents a compensatory mechanism aimed at mitigating congestive heart failure. It is distinguished by progressive dilatation and hypertrophy of the ventricular chambers, fibrotic alterations, and prolonged apoptosis of cardiomyocytes. The primary objective of this study was to assess the effects of icariin on myocardial fibrosis and ventricular remodeling in rats subjected to myocardial infarction (MI).

METHODS

Male Sprague‒Dawley (SD) rats were subjected to randomization and subsequently divided into distinct groups: the control group, the sham group (undergoing sham operation), the MI group (experiencing ligation of the left anterior descending artery), and the icariin group. Within the icariin group, rats were further categorized into three different dose groups based on the administered icariin dosage: the MI30 group (30 mg/kg/day), the MI60 group (60 mg/kg/day), and the MI120 group (120 mg/kg/day). Cardiac function evaluation was carried out using echocardiography. Histological examinations, including hematoxylin and eosin (HE) staining, Masson staining, and immunohistochemistry studies, were conducted 90 days after the occurrence of MI. Additionally, Western blotting was employed to assess TGF-β1, p-Smad2, and p-Smad3 levels.

RESULTS

The administration of icariin revealed a noteworthy enhancement in cardiac function among rats afflicted with left anterior descending coronary artery (LAD) ligation. In comparison to the icariin groups, the MI group exhibited reduced EF and FS, along with elevated LVEDD and LVESD. Furthermore, the cardiac fibrosis levels in the MI group rats exhibited a considerable increase compared to those in the icariin group. Notably, the levels of Collagen I, Collagen III, MMP2, and MMP9 were significantly higher in the MI group than in the icariin group, with evident distinctions. Moreover, the expression levels of TGF-β, IL-13, p-Smad2, and p-Smad3 were notably upregulated in the MI group compared to the icariin group.

CONCLUSIONS

In an experimental rat model of MI, the administration of icariin resulted in the amelioration of both cardiac function and remodeling processes, operating through the intricate TGF-β1/Smad signaling pathway.

Anti-inflammatory effects of icariin in the acute and chronic phases of the mouse pilocarpine model of epilepsy

Neuroinflammation mediated by microglia made a significant contribution in the pathophysiology of epilepsy. Icariin (ICA), a bioactive ingredient isolated from Epimedium, has been shown to present both antioxidant and anti-inflammatory properties. This study was to explore the potential therapeutic effects of icariin on mouse pilocarpine model of epilepsy and its underlying mechanisms in vivo and in vitro. To this end, we firstly measured the serum concentrations of the proinflammatory cytokines IL-1β and IL-6 from patients with temporal lobe epilepsy and found that patients with a higher seizure frequency showed correspondingly higher inflammatory reaction. Mouse pharmacokinetic study, transmembrane transportation assay, and cell viability assay collectively demonstrated that ICA was able to cross the blood-brain barrier and has good biocompatibility. The acute and chronic epilepsy models were next established in a pilocarpine mouse model of acquired epilepsy. Icariin has been identified that it could cross the blood-brain barrier and enter the hippocampus to exhibit therapeutic effects. ICA treatment dramatically promoted microglial polarization to the M2 phenotype in epilepsy mice both in the acute and chronic phases. Reduced release of M1-associated proinflammatory factors, such as IL-1β and IL-6, corroborates the altered glial cell polarization. Furthermore, ICA alleviated seizure intensity and mortality in acute phase epileptic mice. Models in the chronic group also showed improved general condition, cognition ability, and memory function after ICA treatment. Taken together, our research strongly suggested that icariin has the potential to treat epilepsy via inhibiting neuroinflammation by promoting microglial polarization to the M2 phenotype.

Bakuchiol, a natural constituent and its pharmacological benefits

Background and aims

Natural compounds extracted from medicinal plants have recently gained attention in therapeutics as they are considered to have lower Toxicity and higher tolerability relative to chemically synthesized compounds. Bakuchiol from Psoralea corylifolia L. is one such compound; it is a type of meroterpene derived from the leaves and seeds of Psoralea corylifolia plants. Natural sources of bakuchiol have been used in traditional Chinese and Indian medicine for centuries due to its preventive benefits against tumors and inflammation. It plays a strong potential role as an antioxidant with impressive abilities to remove Reactive Oxygen Species (ROS). This review has focused on bakuchiol's extraction, therapeutic applications, and pharmacological benefits.

Methods

A search strategy has been followed to retrieve the relevant newly published literature on the pharmacological benefits of bakuchiol. After an extensive study of the retrieved articles and maintaining the inclusion and exclusion criteria, 110 articles were finally selected for this review.

Results

Strong support of primary research on the protective effects via antitumorigenic, anti-inflammatory, antioxidative, antimicrobial, and antiviral activities are delineated.

Conclusions

From ancient to modern life, medicinal plants have always been drawing the attention of human beings to alleviate ailments for a healthy and balanced lifestyle. This review is a comprehensive approach to highlighting bona fide essential pharmacological benefits and mechanisms underlying their therapeutic applications.

Icariin inhibits hypertrophy by regulation of GPER1 and CaMKII/HDAC4/MEF2C signaling crosstalk in ovariectomized mice

Icariin (ICA), a flavonoid phytoestrogen, was isolated from traditional Chinese medicine Yin Yang Huo (Epimedium brevicornu Maxim.). Previous studies reporting the cardioprotective effects of ICA are available; however, little is known about the impact of ICA on cardioprotection under conditions of reduced estrogen levels. This study aimed to provide detailed information regarding the antihypertrophic effects of ICA in ovariectomized female mice. Female mice were subjected to ovariectomy (OVX) and transverse aortic constriction and then orally treated with ICA at doses of 30, 60 or 120 mg/kg/day for 4 weeks. Morphological assessments, echocardiographic parameters, histological analyses, and immunofluorescence were performed to evaluate cardiac hypertrophy. Cardiomyocytes from mice or rats were stimulated using phenylephrine, and cell surface and hypertrophy markers were tested using immunofluorescence and qPCR. Western blotting, qPCR, and luciferase reporter gene assays were used to assess the expression of proteins and mRNA and further investigate the proteins related to the G-protein coupled estrogen receptor (GPER1) and CaMKII/HDAC4/MEF2C signaling pathways in vivo and in vitro. ICA blocks cardiac hypertrophy induced by pressure overload in OVX mice. Additionally, we demonstrated that ICA activated GPER1 and inhibited the nuclear export or promoted the nuclear import of histone deacetylase 4 (HDAC4) through regulation of phosphorylation of calmodulin-dependent protein kinase II (CaMKII) and further improved the repression of myocyte enhancer factor-2C (MEF2C). ICA ameliorated cardiac hypertrophy in OVX mice by activating GPER1 and inhibiting the CaMKII/HDAC4/MEF2 signaling pathway.

Low-intensity pulsed ultrasound of different intensities differently affects myocardial ischemia/reperfusion injury by modulating cardiac oxidative stress and inflammatory reaction

Introduction

The prevalence of ischemic heart disease has reached pandemic levels worldwide. Early revascularization is currently the most effective therapy for ischemic heart diseases but paradoxically induces myocardial ischemia/reperfusion (MI/R) injury. Cardiac inflammatory reaction and oxidative stress are primarily involved in the pathology of MI/R injury. Low-intensity pulsed ultrasound (LIPUS) has been demonstrated to reduce cell injury by protecting against inflammatory reaction and oxidative stress in many diseases, including cardiovascular diseases, but rarely on MI/R injury.

Methods

This study was designed to clarify whether LIPUS alleviates MI/R injury by alleviating inflammatory reaction and oxidative stress. Simultaneously, we have also tried to confirm which intensity of the LIPUS might be more suitable to ameliorate the MI/R injury, as well as to clarify the signaling mechanisms. MI/R and simulated ischemia/reperfusion (SI/R) were respectively induced in Sprague Dawley rats and human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs). LIPUS treatment, biochemical measurements, cell death assay, estimation of cardiac oxidative stress and inflammatory reaction, and protein detections by western blotting were performed according to the protocol.

Results

In our study, both in vivo and in vitro, LIPUS of 0.1 W/cm2 (LIPUS0.1) and 0.5 W/cm2 (LIPUS0.5) make no significant difference in the cardiomyocytes under normoxic condition. Under the hypoxic condition, MI/R injury, inflammatory reaction, and oxidative stress were partially ameliorated by LIPUS0.5 but were significantly aggravated by LIPUS of 2.5 W/cm2 (LIPUS2.5) both in vivo and in vitro. The activation of the apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK) pathway in cardiomyocytes with MI/R injury was partly rectified LIPUS0.5 both in vivo and in vitro.

Conclusion

Our study firstly demonstrated that LIPUS of different intensities differently affects MI/R injury by regulating cardiac inflammatory reaction and oxidative stress. Modulations on the ASK1/JNK pathway are the signaling mechanism by which LIPUS0.5 exerts cardioprotective effects. LIPUS0.5 is promising for clinical translation in protecting against MI/R injury. This will be great welfare for patients suffering from MI/R injury.

Mechanisms of ferroptosis regulating oxidative stress and energy metabolism in myocardial ischemia-reperfusion injury and a novel perspective of natural plant active ingredients for its treatment

Acute myocardial infarction remains the leading cause of death in humans. Timely restoration of blood perfusion to ischemic myocardium remains the most effective strategy in the treatment of acute myocardial infarction, which can significantly reduce morbidity and mortality. However, after restoration of blood flow and reperfusion, myocardial injury will aggravate and induce apoptosis of cardiomyocytes, a process called myocardial ischemia-reperfusion injury. Studies have shown that the loss and death of cardiomyocytes caused by oxidative stress, iron load, increased lipid peroxidation, inflammation and mitochondrial dysfunction, etc., are involved in myocardial ischemia-reperfusion injury. In recent years, with the in-depth research on the pathology of myocardial ischemia-reperfusion injury, people have gradually realized that there is a new form of cell death in the pathological process of myocardial ischemia-reperfusion injury, namely ferroptosis. A number of studies have found that in the myocardial tissue of patients with acute myocardial infarction, there are pathological changes closely related to ferroptosis, such as iron metabolism disorder, lipid peroxidation, and increased reactive oxygen species free radicals. Natural plant products such as resveratrol, baicalin, cyanidin-3-O-glucoside, naringenin, and astragaloside IV can also exert therapeutic effects by correcting the imbalance of these ferroptosis-related factors and expression levels. Combining with our previous studies, this review summarizes the regulatory mechanism of natural plant products intervening ferroptosis in myocardial ischemia-reperfusion injury in recent years, in order to provide reference information for the development of targeted ferroptosis inhibitor drugs for the treatment of cardiovascular diseases.

A COMPARATIVE ANALYSIS TO DETERMINE THE OPTIMUM HISTONE DEACETYLASE INHIBITORS AND ADMINISTRATION ROUTE FOR IMPROVING SURVIVAL AND ORGAN INJURY IN RATS AFTER HEMORRHAGIC SHOCK

ABSTRACT

Objective: Histone deacetylase inhibitors (HDACIs) have been reported to improve survival in rats with hemorrhagic shock (HS). However, no consensus exists on the most effective HDACIs and their administration routes. We herein aimed to determine the optimal HDACIs and administration route in rats with HS. Methods: Survival analysis: In experiment I, male Sprague-Dawley rats were subjected to HS (mean arterial pressure [MAP] was maintained at 30-40 mm Hg for 20 min), and intravenously injected with the following agents (n = 8 per group): (1) no treatment, (2) vehicle (VEH), (3) entinostat (MS-275), (4) [ N -((6-(Hydroxyamino)-6-oxohexyl)oxy)-3,5-dimethylbenzamide] (LMK-235), (5) tubastatin A, (6) trichostatin A (TSA), and (7) sirtinol. In experiment II, rats were intraperitoneally injected with TSA. Mechanism research: In experiments I and II, rats were observed for 3 h, after which blood samples and liver, heart, and lung tissues were harvested. Results: In experiment I, 75% rats in the VEH group but only 25% rats in the LMK-235 and sirtinol groups died within ≤5 h of treatment, whereas the survival of rats in the MS-275, tubastatin A, and TSA groups was significantly prolonged. MS-275, LMK-235, tubastatin A, and TSA significantly reduced histopathological scores, apoptosis cell numbers, and inflammatory cytokine levels. In experiment II, the survival was longer after i.v. TSA treatment than after i.p. TSA treatment, and the IL-6 levels in the heart were significantly lower in rat who received i.p. TSA treatment than in those who received i.v. TSA treatment. Conclusions: The i.v. effect was superior to the i.p. effect, while nonselective and isoform-specific classes I and IIb HDACIs had similar effects.

Beneficial effects of flavonoids on cardiovascular diseases by influencing NLRP3 inflammasome

Cardiovascular diseases (CVDs) are a leading cause of global mortality and have a high incidence rate worldwide. The function of inflammasomes in CVDs has received a lot of attention recently, and the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome may be a new target for the prevention and treatment of CVDs. Flavonoids, which are found in food and plant extracts, inhibited inflammation in CVDs by regulating the NLRP3 inflammasome. CB-Dock was used to investigate whether 34 flavonoids from natural products acted on NLRP3 inflammasome. In brief, the PDB format of NLRP3 was selected as a protein file, and 34 flavonoids in SDF format were selected as the ligand file, and then input to CB-Dock for molecular docking. The docking results showed that epigallocatechin-3-gallate (EGCG), amentoflavone, baicalin, scutellarin, vitexin, silibinin, and puerarin had good binding affinities to NLRP3, which could be used as NLRP3 inhibitors, and aid in the discovery of lead compounds for the design and development of CVDs.

Pharmacology-Based Prediction of the Targets and Mechanisms for Icariin against Myocardial Infarction

Background and Objectives: This study aims to illustrate the mechanisms underlying the therapeutic effect of Icariin after myocardial infarction (MI). Materials and Methods: Based on the network pharmacology strategy, we predict the therapeutic targets of Icariin against MI and investigate the pharmacological molecular mechanisms. A topological network was created. Biological process and Kyoto Encyclopedia of Genes and Genomes pathway enrichment were also performed. We also conducted the molecular docking analysis to stimulate the component–target interaction further and validate the direct bind effect. Results: Network pharmacology analysis identified 61 candidate genes related to the therapeutic effect of Icariin against MI. EGFR, AKT1, TP53, JUN, ESR1, PTGS2, TNF, RELA, HSP90AA1, and BCL2L1 were identified as hub genes. The biological processes of the candidate targets were significantly involved in the reactive oxygen species metabolic process, response to hypoxia, response to decreased oxygen levels, response to oxidative stress, regulation of reactive oxygen species metabolic process, and so forth. Overall, biological process enrichment analysis indicated that the protective effect of Icariin against MI might be associated with oxidative stress. Moreover, the pathway analysis showed that the candidate targets were closely associated with lipid and atherosclerosis, AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, etc. We identified the conformation with the lowest affinity score as the docking conformation. The simulated molecular docking was displayed to illustrate the topical details of the binding sites between Icariin and TNF protein. Conclusions: This study provides an overview of the mechanisms underlying the protective effect of Icariin against MI.

Effect of icariin on the H2O2-induced proliferation of mouse airway smooth muscle cells through miR-138-5p regulating SIRT1/AMPK/PGC-1α axis

Icariin exerts antioxidative and anti-inflammatory effects and is used in the treatment of bronchial asthma. However, the specific modes of action are uncertain. In this study, we investigated whether icariin could modulate the silencing information regulator 2-related enzyme 1 (SIRT1)/adenosine monophosphate-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) axis by regulating miR-138-5p during H₂O₂-induced proliferation of mouse airway smooth muscle cells (ASMCs). Primary BALB/c mouse ASMCs were cultured using the tissue block adherence method and were induced with hydrogen peroxide (H₂O₂; 200 μmol/L) to establish a bronchial asthma ASMC proliferation model. With the aid of Western Blot and quantitative real-time polymerase chain reaction (qRT-PCR) in H₂O₂-induced ASMCs, the expression of miR-138-5p, SIRT1, AMPK, PGC-1α, α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), collagen I, and collagen III protein and mRNA were investigated. The proliferation rate and activities of superoxide dismutase1 (SOD1), reduced glutathione (GSH), malonaldehyde (MDA), and reactive oxygen species (ROS) in ASMCs were determined. The results suggest Compared with the H₂O₂-induced group, icariin inhibited the miR-138-5p expression; enhanced SIRT1, p-AMPK, and PGC-1α expression; attenuated MDA activity and ROS level; lowered TGF-β1, collagen I, and collagen III expression levels; and decreased the proliferation of ASMCs induced by H₂O₂. The dual-luciferase reporter gene assay results showed that SIRT1 is a regulatory target of miR-138-5p.The results suggest that Icariin could improve the H₂O₂-induced proliferation of ASMCs. The mechanism may be related to the increase of activation of SIRT1/AMPK/PGC-1α axis by suppressing the expression of miR-138-5p. Thus, SIRT1 is the regulatory target of miR-138-5p.

Regulatory mechanism of icariin in cardiovascular and neurological diseases

Cardiovascular diseases (CVDs) and neurological diseases are widespread diseases with substantial rates of morbidity and mortality around the world. For the past few years, the preventive effects of Chinese herbal medicine on CVDs and neurological diseases have attracted a great deal of attention. Icariin (ICA), the main constituent of Epimedii Herba, is a flavonoid. It has been shown to provide neuroprotection, anti-tumor, anti-osteoporosis, and cardiovascular protection. The endothelial protection, anti-inflammatory, hypolipidemic, antioxidative stress, and anti-apoptosis properties of ICA can help stop the progression of CVDs and neurological diseases. Therefore, our review summarized the known mechanisms and related studies of ICA in the prevention and treatment of cardio-cerebrovascular diseases (CCVDs), to better understand its therapeutic potential.

Inhibition of ferroptosis by icariin treatment attenuates excessive ethanol consumption-induced atrial remodeling and susceptibility to atrial fibrillation, role of SIRT1

Ferroptosis contributes to the pathogenesis of atrial fibrillation (AF), although the mechanisms are still largely uncovered. The current study was designed to explore the pharmacological effects of icariin against ethanol-induced atrial remodeling, if any, and the mechanisms involved with a focus on SIRT1 signaling. Excessive ethanol-treated animals were administered with Ferrostatin-1, Erastin or icariin to evaluate the potential effects of icariin or ferroptosis. Then, the underling mechanisms was further explored in the in vitro experiments using HL-1 atrial myocytes. Excessive ethanol administration caused significant atrial damage as evidenced by increased susceptibility to AF, altered atrial conduction pattern, atrial enlargement, and enhanced fibrotic markers. These detrimental effects were reversed by Ferrostatin-1 or icariin treatment, while Erastin co-administration markedly abolished the beneficial actions conferred by icariin. Mechanistically, ethanol-treated atria exhibited markedly up-regulated pro-ferroptotic protein (PTGS2, ACSL4, P53) and suppressed anti-ferroptotic molecules (GPX4, FTH1). Icariin treatment inhibited ethanol-induced atrial ferroptosis by reducing atrial mitochondrial damage, ROS accumulation and iron overload. Interestingly, the in vivo and in vitro data showed that icariin activated atrial SIRT1-Nrf-2-HO-1 signaling pathway, while EX527 not only reversed these effects, but also abolished the therapeutic effects of icariin. Moreover, the stimulatory effects on GPX4, SLC7A11 and the suppressive effects on ACSL4, P53 conferred by icariin were blunted by EX527 treatment. These data demonstrate that ferroptosis plays a causative role in the pathogenesis of ethanol-induced atrial remodeling and susceptibility to AF. Icariin protects against atrial damage by inhibiting ferroptosis via SIRT1 signaling. Its role as a prophylactic/therapeutic drug deserves further clinical study.

Linggui Zhugan Decoction activates the SIRT1-AMPK-PGC1α signaling pathway to improve mitochondrial and oxidative damage in rats with chronic heart failure caused by myocardial infarction

Objective: To investigate the effects of Linggui Zhugan Decoction on mitochondrial and oxidative damage in rats with chronic heart failure after myocardial infarction and the related mechanisms. Methods: Chronic heart failure after myocardial infarction was established by coronary artery ligation. Heart failure rats were randomly divided into three groups: Model group (n = 11), Linggui Zhugan Decoction group (n = 12), and captopril group (n = 11). Rats whose coronary arteries were only threaded and not ligated were sham group (n = 11). Cardiac function, superoxide dismutase (SOD), malondialdehyde (MDA) contents, soluble growth-stimulating expression factor (ST2), and N-terminal B-type brain natriuretic peptide precursor (NTproBNP) levels were analyzed after treatment. Moreover, the level of mitochondrial membrane potential was detected by JC-1 staining, the ultrastructural of myocardial mitochondria were observed by transmission electron microscopy. The related signal pathway of silent information regulator factor 2-related enzyme 1 (SIRT1), adenylate activated protein kinase (AMPK), phosphorylated adenylate activated protein kinase (p-AMPK), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is an important pathway to regulate mitochondrial energy metabolism, and to initiate mitochondrial biogenesis. The expression level was detected by Western blot and reverse transcription to explore the mechanism of the decoction. Results: Compared with the model rats, Linggui Zhugan Decoction significantly improved cardiac function (p < 0.05), reduced MDA production (p < 0.01), increased SOD activity (p < 0.05), reduced ST-2(p < 0.01), and NT-proBNP(p < 0.05) levels, increased mitochondrial membrane potential, and improved mitochondria function. In addition, Linggui Zhugan Decoction upregulated the expression of SIRT1, p-AMPK, PGC-1α protein, and mRNA in cardiac myocytes. Conclusion: Linggui Zhugan Decoction can improve the cardiac function of heart failure rats by enhancing myocardial antioxidant capacity and protecting the mitochondrial function, the mechanism is related to activating SIRT1/AMPK/PGC-1α signaling pathway.

Advances in research on the protective mechanisms of traditional Chinese medicine (TCM) in myocardial ischaemia-reperfusion injury

CONTEXT

Developing effective drugs to treat myocardial ischaemia-reperfusion (MI/R) injury is imperative. Traditional Chinese medicines (TCMs) have had considerable success in the treatment of cardiovascular diseases. Elucidating the mechanisms by which TCMs improve MI/R injury can supplement the literature on MI/R prevention and treatment.

OBJECTIVE

To summarise TCMs and their main protective mechanisms against MI/R injury reported over the past 40 years.

METHODS

Relevant literature published between 1980 and 2020 in Chinese and English was retrieved from the Web of Science, PubMed, SpringerLink, PubMed Central, Scopus, and Chinese National Knowledge Infrastructure (CNKI) databases. Search terms included 'medicinal plants', 'myocardial ischaemia reperfusion injury', 'Chinese medicine prescriptions', 'mechanisms', 'prevention', 'treatment' and 'protection'. For inclusion in the analysis, medicinal plants had to be searchable in the China Medical Information Platform and Plant Database.

RESULTS

We found 71 medicinal species (from 40 families) that have been used to prevent MI/R injury, of which Compositae species (8 species) and Leguminosae species (7 species) made up the majority. Most of the effects associated with these plants are described as antioxidant and anti-inflammatory. Furthermore, we summarised 18 kinds of Chinese compound prescriptions, including the compound Danshen tablet and Baoxin pill, which mainly reduce oxidative stress and regulate mitochondrial energy metabolism.

DISCUSSION AND CONCLUSIONS

We summarised TCMs that protect against MI/R injury and their pharmacological mechanisms. This in-depth explanation of the roles of TCMs in MI/R injury protection provides a theoretical basis for the research and development of TCM-based treatment drugs.

SIRT6 in Aging, Metabolism, Inflammation and Cardiovascular Diseases

As an important NAD⁺-dependent enzyme, SIRT6 has received significant attention since its discovery. In view of observations that SIRT6-deficient animals exhibit genomic instability and metabolic disorders and undergo early death, SIRT6 has long been considered a protein of longevity. Recently, growing evidence has demonstrated that SIRT6 functions as a deacetylase, mono-ADP-ribosyltransferase and long fatty deacylase and participates in a variety of cellular signaling pathways from DNA damage repair in the early stage to disease progression. In this review, we elaborate on the specific substrates and molecular mechanisms of SIRT6 in various physiological and pathological processes in detail, emphasizing its links to aging (genomic damage, telomere integrity, DNA repair), metabolism (glycolysis, gluconeogenesis, insulin secretion and lipid synthesis, lipolysis, thermogenesis), inflammation and cardiovascular diseases (atherosclerosis, cardiac hypertrophy, heart failure, ischemia-reperfusion injury). In addition, the most recent advances regarding SIRT6 modulators (agonists and inhibitors) as potential therapeutic agents for SIRT6-mediated diseases are reviewed.

Pterostilbene Attenuates Subarachnoid Hemorrhage-Induced Brain Injury through the SIRT1-Dependent Nrf2 Signaling Pathway

Neuroinflammatory injury, oxidative insults, and neuronal apoptosis are major causes of poor outcomes after subarachnoid hemorrhage (SAH). Pterostilbene (PTE), an analog of resveratrol, has been verified as a potent sirtuin 1 (SIRT1) activator. However, the beneficial actions of PTE on SAH-induced brain injury and whether PTE regulates SIRT1 signaling after SAH remain unknown. We first evaluated the dose-response influence of PTE on early brain impairment after SAH. In addition, EX527 was administered to suppress SIRT1 signaling. The results revealed that PTE significantly attenuated microglia activation, oxidative insults, neuronal damage, and early neurological deterioration. Mechanistically, PTE effectively enhanced SIRT1 expression and promoted nuclear factor-erythroid 2-related factor 2 (Nrf2) accumulation in nuclei. Furthermore, EX527 pretreatment distinctly repressed PTE-induced SIRT1 and Nrf2 activation and deteriorated these beneficial outcomes. In all, our study provides the evidence that PTE protects against SAH insults by activating SIRT1-dependent Nrf2 signaling pathway. PTE might be a therapeutic alternative for SAH.

Natural Compounds for SIRT1-Mediated Oxidative Stress and Neuroinflammation in Stroke: A Potential Therapeutic Target in the Future

Stroke is a fatal cerebral vascular disease with a high mortality rate and substantial economic and social costs. ROS production and neuroinflammation have been implicated in both hemorrhagic and ischemic stroke and have the most critical effects on subsequent brain injury. SIRT1, a member of the sirtuin family, plays a crucial role in modulating a wide range of physiological processes, including apoptosis, DNA repair, inflammatory response, and oxidative stress. Targeting SIRT1 to reduce ROS and neuroinflammation might represent an emerging therapeutic target for stroke. Therefore, we conducted the present review to summarize the mechanisms of SIRT1-mediated oxidative stress and neuroinflammation in stroke. In addition, we provide a comprehensive introduction to the effect of compounds and natural drugs on SIRT1 signaling related to oxidative stress and neuroinflammation in stroke. We believe that our work will be helpful to further understand the critical role of the SIRT1 signaling pathway and will provide novel therapeutic potential for stroke treatment.

Icariin exhibits protective effects on cisplatin-induced cardiotoxicity via ROS-mediated oxidative stress injury in vivo and in vitro

BACKGROUND

Cisplatin-induced cardiotoxicity severely limits its clinical application as an antitumor drug and increases the risk of cardiovascular disease. Icariin (ICA), the main flavonoid isolated from Epimedii Folium, has been demonstrated to have various beneficial effects on cardiovascular disease. However, the protective effect of ICA against cisplatin-induced cardiotoxicity remains unclear.

PURPOSE

In present study, we explored the protective action of ICA against cisplatin-induced cardiotoxicity and its possible molecular mechanisms in vitro and in vivo.

METHODS

Mice were intraperitoneally injected with cisplatin 4 mg/kg every other day for 7 times to establish myocardial injury model. ICA (15, 30 mg/kg) was administered to mice by gavage for 21 days. H9c2 cells were treated with ICA (3, 6, 12 µM) in the presence or absence of cisplatin (40 µM), and then cell viability, oxidative stress, apoptosis, and mitochondrial function were evaluated.

RESULTS

Biochemical index detection and histopathological staining analysis showed that ICA had a good protective effect on cisplatin-induced cardiotoxicity. Cellular experiments showed that ICA inhibited cisplatin-induced oxidative stress in a dose-dependent manner by regulating the levels of glutathione peroxidase (GSH-Px), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA). ICA could inhibit the expression of NF-κB and the secretion of inflammatory factors, thereby alleviating the inflammatory injury caused by cisplatin. In addition, ICA could alleviate cisplatin-induced myocardial injury by activating SIRT1 and PI3K/Akt signaling pathways and inhibiting MAPKs signaling pathway.

CONCLUSION

These results suggest that ICA could attenuate cisplatin-induced cardiac injury by inhibiting oxidative stress, inflammation and apoptosis, laying a foundation for ICA to reduce chemotherapy-induced cardiotoxicity in clinical practice.

A Systematic Review and Meta-Analysis of Phytoestrogen Protects Against Myocardial Ischemia/Reperfusion Injury: Pre-Clinical Evidence From Small Animal Studies

Background: Phytoestrogens are a class of natural compounds that have structural similarities to estrogens. They have been identified to confer potent cardioprotective effects in experimental myocardial ischemia-reperfusion injury (MIRI) animal models. We aimed to investigate the effect of PE on MIRI and its intrinsic mechanisms. Methods: A systematic search was conducted to identify PEs that have been validated in animal studies or clinical studies as effective against MIRI. Then, we collected studies that met inclusion and exclusion criteria from January 2016 to September 2021. The SYRCLE's RoB tool was used to evaluate the quality. Data were analyzed by STATA 16.0 software. Results: The search yielded 18 phytoestrogens effective against heart disease. They are genistein, quercetin, biochanin A, formononetin, daidzein, kaempferol, icariin, puerarin, rutin, notoginsenoside R1, tanshinone IIA, ginsenoside Rb1, ginsenoside Rb3, ginsenoside Rg1, ginsenoside Re, resveratrol, polydatin, and bakuchiol. Then, a total of 20 studies from 17 articles with a total of 355 animals were included in this meta-analysis. The results show that PE significantly reduced the myocardial infarct size in MIRI animals compared with the control group (p < 0.001). PE treatment significantly reduced the creatine kinase level (p < 0.001) and cTnI level (p < 0.001), increased left ventricular ejection fraction (p < 0.001) and left ventricular fractional shortening (p < 0.001) in MIRI animals. In addition, PE also exerts a significant heart rate lowering effect (p < 0.001). Conclusion: Preclinical evidence suggests that PE can be multi-targeted for cardioprotective effects in MIRI. More large animal studies and clinical research are still needed in the future to further confirm its role in MIRI.

Cycloastragenol Confers Cerebral Protection after Subarachnoid Hemorrhage by Suppressing Oxidative Insults and Neuroinflammation via the SIRT1 Signaling Pathway

Subarachnoid hemorrhage (SAH) is an acute cerebral vascular disease featured by oxidative insults and neuroinflammation. Cycloastragenol (CAG), the major active component of Astragalus radix, has a wide range of biological functions. However, the potential beneficial effects and the underlying molecular mechanisms of CAG on SAH remain obscure. In the current study, the cerebroprotective effects and mechanism of CAG on SAH were evaluated both in vivo and in vitro. Our results indicated that CAG significantly suppressed SAH-triggered oxidative insults, inflammatory mediators production, microglia activation, and the neutrophil infiltration in the brain. In addition, CAG improved neurological function and ameliorated neuronal apoptosis and degeneration after SAH. In vitro results also revealed the therapeutic effects of CAG on neurons and microglia co-culture system. Mechanistically, CAG treatment upregulated sirtuin 1 (SIRT1) expression, inhibited the levels of FoxO1, nuclear factor-kappa B, and p53 acetylation, and suppressed the subsequent oxidative, inflammatory, and apoptotic pathways. In contrast, inhibiting SIRT1 by pretreatment with Ex527 abrogated the protective actions of CAG both in vivo and in vitro models of SAH. Collectively, our findings indicated that CAG could be a promising and effective drug candidate for SAH.

Catalpol Enhances Random-Pattern Skin Flap Survival by Activating SIRT1-Mediated Enhancement of Autophagy

Random-pattern skin flap necrosis limits its application in the clinic. It is still a challenge for plastic surgeons. Catalpol is an effective ingredient extracted from Rehmannia glutinosa, which is reported to promote angiogenesis and protect against ischemic cerebral disease. The aim of our experiment is to assess whether catalpol can facilitate random flap survival and the underlying mechanisms. Male “McFarlane flap” rat models were employed to explore the protective effects of catalpol. The range of necrosis in the flap was calculated 7 days after the models were established. The flap specimens were harvested for further experiments, including angiogenesis, apoptosis, oxidative stress, and autophagy evaluation. Catalpol-treated group promoted the average survival area of the flap than that in the control group. Based on immunohistochemical staining, Western blotting, and ROS detection, we found that catalpol significantly reduces oxidative stress and apoptosis and increases angiogenesis. Hematoxylin and eosin (H&E) staining and laser Doppler images further clarified the enhancement of angiogenesis after catalpol treatment. The impact of catalpol in flap was switched by using 3-methyladenine (3MA), proving the important role of autophagy in curative effect of catalpol on skin flaps. Importantly, the ability of catalpol to regulate autophagy is mediated by the activation of sirtuin 1 (SIRT1) based on its high affinity for SIRT1. Our findings revealed that catalpol improved the viability of random skin flaps by activating SIRT1-mediated autophagy pathway.

Baohuoside I Inhibits Osteoclastogenesis and Protects Against Ovariectomy-Induced Bone Loss

Bone-resorbing osteoclasts are essential for skeletal remodelling, and the hyperactive formation and function of osteoclasts are common in bone metabolic diseases, especially postmenopausal osteoporosis. Therefore, regulating the osteoclast differentiation is a major therapeutic target in osteoporosis treatment. Icariin has shown potential osteoprotective effects. However, existing studies have reported limited bioavailability of icariin, and the material basis of icariin for anti-osteoporosis is attributed to its metabolites in the body. Here, we compared the effects of icariin and its metabolites (icariside I, baohuoside I, and icaritin) on osteoclastogenesis by high-content screening followed by TRAP staining and identified baohuoside I (BS) with an optimal effect. Then, we evaluated the effects of BS on osteoclast differentiation and bone resorptive activity in both in vivo and in vitro experiments. In an in vitro study, BS inhibited osteoclast formation and bone resorption function in a dose-dependent manner, and the elevated osteoclastic-related genes induced by RANKL, such as NFATc1, cathepsin K, RANK, and TRAP, were also attenuated following BS treatment. In an in vivo study, OVX-induced bone loss could be prevented by BS through interrupting the osteoclast formation and activity in mice. Furthermore, mechanistic investigation demonstrated that BS inhibited osteoclast differentiation by ameliorating the activation of the MAPK and NF-kB pathways and reducing the expression of uPAR. Our study demonstrated that baohuoside I could inhibit osteoclast differentiation and protect bone loss following ovariectomy.

Protective effects of natural products against myocardial ischemia/reperfusion: Mitochondria-targeted therapeutics

Patients with ischemic heart disease receiving reperfusion therapy still need to face left ventricular remodeling and heart failure after myocardial infarction. Reperfusion itself paradoxically leads to further cardiomyocyte death and systolic dysfunction. Ischemia/reperfusion (I/R) injury can eliminate the benefits of reperfusion therapy in patients and causes secondary myocardial injury. Mitochondrial dysfunction and structural disorder are the basic driving force of I/R injury. We summarized the basic relationship and potential mechanisms of mitochondrial injury in the development of I/R injury. Subsequently, this review summarized the natural products (NPs) that have been proven to targeting mitochondrial therapeutic effects during I/R injury in recent years and related cellular signal transduction pathways. We found that these NPs mainly protected the structural integrity of mitochondria and improve dysfunction, such as reducing mitochondrial division and fusion abnormalities, improving mitochondrial Ca²⁺ overload and inhibiting reactive oxygen species overproduction, thereby playing a role in protecting cardiomyocytes during I/R injury. This data would deepen the understanding of I/R-induced mitochondrial pathological process and suggested that NPs are expected to be transformed into potential therapies targeting mitochondria.

Research on natural products from traditional Chinese medicine in the treatment of myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a complicated pathologic process that involves multiple factors including oxidative stress (free radical damage), inflammatory response, calcium overloading, and apoptosis in cardiomyocytes. According to Traditional Chinese Medicine (TCM), MIRI belongs to the categories of "chest numbness", "palpitations" and "angina pectoris". Present data indicate that the application of TCM in myocardial ischemia-reperfusion injury is promising and continues to attract research attention. While the efficacy of Chinese herbal medicine has been well-proven, the underlying molecular mechanisms remain elusive. The common proven mechanisms of Chinese herbal medicine in the treatment of MIRI include regulating lipid metabolism, protecting mitochondria, and improving energy metabolism, attenuating calcium (Ca²⁺) overload, scavenging oxygen free radicals, inhibiting apoptosis, and reducing autophagy. Others are the regulation of inflammatory cytokine expressions and healing of inflammatory lesions, modulation of cell signaling pathways, improvement of endothelial cell function, and protection of myocardial cells. In this review, we highlight recent studies that focus on elucidating these molecular mechanisms and the therapeutic effects of natural compounds deriving from TCM in MIRI, to ascertain the research progress made and the prospects in this field.

Fibroblast growth factor 20 attenuates pathological cardiac hypertrophy by activating the SIRT1 signaling pathway

Cardiac hypertrophy occurs initially in response to an increased cardiac load as a compensatory mechanism to maintain cardiac output. However, sustained pathological hypertrophy can develop into heart failure and cause sudden death. Fibroblast growth factor 20 (FGF20) is a member of the fibroblast growth factor family, which involved in apoptosis, aging, inflammation, and autophagy. The precise function of FGF20 in pathological cardiac hypertrophy is unclear. In this study, we demonstrated that FGF20 was significantly decreased in response to hypertrophic stimulation. In contrast, overexpression of FGF20 protected against pressure overload-induced cardiac hypertrophy. Mechanistically, we found that FGF20 upregulates SIRT1 expression, causing deacetylation of FOXO1; this effect promotes the transcription of downstream antioxidant genes, thus inhibits oxidative stress. In content, the anti-hypertrophic effect of FGF20 was largely counteracted in SIRT1-knockout mice, accompanied by an increase in oxidative stress. In summary, our findings reveal a previously unknown protective effect of FGF20 on pathological cardiac hypertrophy by reducing oxidative stress through activation of the SIRT1 signaling pathway. FGF20 is a potential novel molecular target for preventing and treating pressure overload-induced myocardial injury.

Fucoxanthin Attenuates Oxidative Damage by Activating the Sirt1/Nrf2/HO-1 Signaling Pathway to Protect the Kidney from Ischemia-Reperfusion Injury

Oxidative stress is a key component of renal ischemia/reperfusion (I/R) injury. Fucoxanthin (Fx), a marine carotenoid with enhanced antioxidant capacity, acts as a ROS inhibitor in diseases such as ischemic stroke and acute lung injury. We hypothesized that fucoxanthin could attenuate renal I/R-induced oxidative damage. C57BL/6 mice ( $n=30$ ) were randomly assigned to sham, IR, $\text{IR}+\text{DMSO}$ , and $\text{IR}+\text{Fx}$ (25, 50, and 100 mg/kg) groups. The renal I/R injury was induced by clamping the left kidney nephron tip in mice. Fucoxanthin was injected intraperitoneally 24 hours before surgery. Compared with the IR group, pretreatment with fucoxanthin significantly improved renal dysfunction and tissue structural damage and inhibited ROS levels and apoptosis. Consistent results were observed in HK-2 cells. Besides, we found that renal I/R resulted in decreased expression of Sirt1, Nrf2, and HO-1, while fucoxanthin upregulated the expression of Sirt1, Nrf2, and HO-1. The protective effects of fucoxanthin were significantly reversed by EX527 (a selective inhibitor of Sirt1) or si-Sirt1. In conclusion, our study investigated the protective effect of fucoxanthin against renal I/R injury, and the underlying mechanism may be related to the activation of the Sirt1/Nrf2/HO-1 signaling pathway by fucoxanthin to attenuate oxidative stress-induced apoptosis.

Icariin arrests cell cycle progression and induces cell apoptosis through the mitochondrial pathway in human fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a highly disabling autoimmune disorder, characterized by the proliferation of Fibroblast-like Synoviocytes (FLSs). Icariin is a prenylated flavonol glycoside extracted from the medical plant Epimedium, which can inhibit the proliferation and migration of FLSs. However, the potential mechanism of icariin to alleviate RA remains unclear. In this study, icariin inhibited the migration and proliferation of FLSs in a concentration-dependent manner, by inducing G2/M phase arrest and apoptosis. Icariin reduced the mitochondrial transmembrane potential, upregulated cytosolic cytochrome c and increased the level of intracellular reactive oxygen species (ROS). In conclusion, icariin inhibited the proliferation of FLSs by interfering with the cell cycle process and inducing cell apoptosis, suggesting its potential use for the treatment of RA.

The Combination of β-Asarone and Icariin Inhibits Amyloid-β and Reverses Cognitive Deficits by Promoting Mitophagy in Models of Alzheimer's Disease

β-Asarone is the main constituent of Acorus tatarinowii Schott and exhibits important effects in diseases such as neurodegenerative and neurovascular diseases. Icariin (ICA) is a major active ingredient of Epimedium that has attracted increasing attention because of its unique pharmacological effects in degenerative disease. In this paper, we primarily explored the effects of the combination of β-asarone and ICA in clearing noxious proteins and reversing cognitive deficits. The accumulation of damaged mitochondria and mitophagy are hallmarks of aging and age-related neurodegeneration, including Alzheimer's disease (AD). Here, we provide evidence that autophagy/mitophagy is impaired in the hippocampus of APP/PS1 mice and in Aβ1-42-induced PC12 cell models. Enhanced mitophagic activity has been reported to promote Aβ and tau clearance in in vitro and in vivo models. Meanwhile, there is growing evidence that treatment of AD should be preceded by intervention before the formation of pathological products. The efficacy of the combination therapy was better than that of the individual therapies applied separately. Then, we found that the combination therapy also inhibited cell and mitochondrial damage by inducing autophagy/mitophagy. These findings suggest that impaired removal of defective mitochondria is a pivotal event in AD pathogenesis, and that combination treatment with mitophagy inducers represents a potential strategy for therapeutic intervention.

Icariin improves testicular dysfunction via enhancing proliferation and inhibiting mitochondria-dependent apoptosis pathway in high-fat diet and streptozotocin-induced diabetic rats

BACKGROUND

Diabetes mellitus (DM), a chronic metabolic disease, severely impairs male reproductive function. However, the underpinning mechanisms are still incompletely defined, and there are no effective strategies or medicines for these reproductive lesions. Icariin (ICA), the main active component extracted from Herba epimedii, is a flavonoid traditionally used to treat testicular dysfunction. Whether ICA can improve male reproductive dysfunction caused by DM and its underlying mechanisms are still unclear. In this study, by employing metformin as a comparative group, we evaluated the protective effects of ICA on male reproductive damages caused by DM and explored the possible mechanisms.

METHODS

Rats were fed with a high fat diet (HFD) and then intraperitoneally injected with streptozotocin (STZ) to induce diabetes. Diabetic rats were randomly divided into T2DM + saline group, T2DM + metformin group and T2DM + ICA group. Rats without the treatment of HFD and STZ were used as control group. The morphology of testicular tissues was examined by histological staining. The mRNA expression levels were determined by quantitative real-time PCR. Immunostaining detected the protein levels of proliferating cell nuclear antigen (PCNA), hypoxia-inducible factor 1-alpha (HIF-1α) and sirtuin 1 (SIRT1) in testicular tissues. TUNEL assay was performed to determine cell apoptosis in the testicular tissues. The protein expression levels of HIF-1α and SIRT1 in the testicular tissues were determined by western blot assay.

RESULTS

ICA effectively improved male reproductive dysfunction of diabetic rats. ICA administration significantly decreased fasting blood glucose (FBG) and insulin resistance index (IRI). In addition, ICA increased testis weight, epididymis weight, sperm number, sperm motility and the cross-sectional area of seminiferous tubule. ICA recovered the number of spermatogonia, primary spermatocytes and Sertoli cells. Furthermore, ICA upregulated the expression of PCNA, activated SRIT1-HIF-1α signaling pathway, and inhibited intrinsic mitochondria dependent apoptosis pathway by upregulating the expression of Bcl-2 and downregulating the expression of Bax and caspase 3.

CONCLUSION

These results suggest that ICA could attenuate male reproductive dysfunction of diabetic rats possibly via increasing cell proliferation and decreasing cell apoptosis of testis. ICA potentially represents a novel therapeutic strategy against DM-induced testicular damages.

Role of NLRP3 Inflammasome in Lupus Nephritis and Therapeutic Targeting by Phytochemicals

Systemic lupus erythematosus (SLE) is a multisystem autoimmune inflammatory condition that affects multiple organs and provokes extensive and severe clinical manifestations. Lupus nephritis (LN) is one of the main clinical manifestations of SLE. It refers to the deposition of immune complexes in the glomeruli, which cause kidney inflammation. Although LN seriously affects prognosis and represents a key factor of disability and death in SLE patients, its mechanism remains unclear. The NACHT, leucine-rich repeat (LRR), and pyrin (PYD) domains-containing protein 3 (NLRP3) inflammasome regulates IL-1β and IL-18 secretion and gasdermin D-mediated pyroptosis and plays a key role in innate immunity. There is increasing evidence that aberrant activation of the NLRP3 inflammasome and downstream inflammatory pathways play an important part in the pathogenesis of multiple autoimmune diseases, including LN. This review summarizes research progress on the elucidation of NLRP3 activation, regulation, and recent clinical trials and experimental studies implicating the NLRP3 inflammasome in the pathophysiology of LN. Current treatments fail to provide durable remission and provoke several sides effects, mainly due to their broad immunosuppressive effects. Therefore, the identification of a safe and effective therapeutic approach for LN is of great significance. Phytochemicals are found in many herbs, fruits, and vegetables and are secondary metabolites of plants. Evidence suggests that phytochemicals have broad biological activities and have good prospects in a variety of diseases, including LN. Therefore, this review reports on current research evaluating phytochemicals for targeting NLRP3 inflammasome pathways in LN therapy.

Icariin, an Up-and-Coming Bioactive Compound Against Neurological Diseases: Network Pharmacology-Based Study and Literature Review

Icariin is a biologically active substance in Epimedii herba that is used for the treatment of neurologic disorders. However, a comprehensive analysis of the molecular mechanisms of icariin is lacking. In this review, we present a brief history of the use of icariin for medicinal purposes; describe the active chemical components of Epimedii herba; and examine the evidence from experimental studies that have uncovered molecular targets of icariin in different diseases. We also constructed a protein–protein interaction network and carried out Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses to predict the therapeutic actions of icariin in nervous system diseases including Alzheimer disease, Parkinson disease, ischemic stroke, depressive disorder, multiple sclerosis, glioblastoma, and hereditary spastic paraplegias. The results of our analyses can guide future studies on the application of icariin to the treatment of neurologic disorders.

Ethyl pyruvate: A newly discovered compound against ischemia-reperfusion injury in multiple organs

Ischemia-reperfusion injury (IRI) is a process whereby an initial ischemia injury and subsequent recovery of blood flow, which leads to the propagation of an innate immune response and the changes of structural and functional of multiple organs. Therefore, IRI is considered to be a great challenge in clinical treatment such as organ transplantation or coronary angioplasty. In recent years, ethyl pyruvate (EP), a derivative of pyruvate, has received great attention because of its stability and low toxicity. Previous studies have proved that EP has various pharmacological activities, including anti-inflammation, anti-oxidative stress, anti-apoptosis, and anti-fibrosis. Compelling evidence has indicated EP plays a beneficial role in a variety of acute injury models, such as brain IRI, myocardial IRI, renal IRI, and hepatic IRI. Moreover, EP can not only effectively inhibit multiple IRI-induced pathological processes, but also improve the structural and functional lesion of tissues and organs. In this study, we review the recent progress in the research on EP and discuss their implications for a better understanding of multiple organ IRI, and the prospects of targeting the EP for therapeutic intervention.

The investigation of the role of sirtuin-1 on embryo implantation in oxidative stress-induced mice

PURPOSE

Implantation is essential for a successful pregnancy. Despite the increasing number of studies, implantation is still an unknown process. This study aimed to determine whether sirtuin-1 has a role in embryo implantation in oxidative stress-induced mice.

METHODS

Pregnant mice were separated into 5 groups: control, vehicle, paraquat, SRT1720, and SRT1720+Paraquat. Paraquat is a herbicide and is used to induce oxidative stress. SRT1720 is a specific sirtuin-1 activator. Implantation and inter-implantation sites were removed in the morning of the 5th day of pregnancy after Chicago blue injection was performed. Sirtuin-1 and Forkhead box O1 (FoxO1) were detected by immunohistochemistry and Western blot while acetylated lysine was evaluated by Western blot analysis. Reactive oxygen and nitrogen species (ROS/RNS) and superoxide dismutase (SOD) activity were determined by fluorometric and spectrometric methods, respectively.

RESULTS

Although there was no embryo implantation in paraquat-treated mice, 5 out of 9 SRT1720+Paraquat-treated mice had implantation sites which were significantly higher compared to the paraquat-treated group. Sirtuin-1 and FoxO1 expressions were increased at implantation sites of SRT1720-treated mice. ROS/RNS levels were decreased, while deacetylated FoxO1 levels and SOD activity were increased in SRT1720-treated mice.

CONCLUSION

Our findings suggest that sirtuin-1 may play a role in embryo implantation against oxidative stress through FoxO1-SOD signaling.

Hypoxic postconditioning-induced neuroprotection increases neuronal autophagy via activation of the SIRT1/FoxO1 signaling pathway in rats with global cerebral ischemia

Hypoxic postconditioning (HPC) has been reported to be a beneficial and promising treatment for global cerebral ischemia (GCI). However, its neuroprotective mechanism remains unclear. The aim of the present study was to determine whether the protective effects of HPC in a rat model of GCI were due to the upregulation of autophagy via the silent information regulator transcript-1 (SIRT1)/Forkhead box protein 1 (FoxO1) pathway. Morris water maze test revealed that HPC attenuated cognitive damage in GCI rats. HPC also significantly increased the levels of the autophagy-related protein LC3-II, SIRT1 and FoxO1 compared with those in the GCI group. However, the HPC-induced LC3-II upregulation was blocked by the SIRT1 inhibitor EX527. These results suggested that the beneficial effects of HPC on GCI rats were due to the upregulation of ischemiainduced autophagy and involved the SIRT1/FoxO1 signaling pathway.

The mitochondrial biogenesis signaling pathway is a potential therapeutic target for myasthenia gravis via energy metabolism (Review)

Myasthenia gravis (MG) is an autoantibody-mediated autoimmune disease that is characterized by muscle weakness and fatigue. Traditional treatments for MG target the neuromuscular junction (NMJ) or the immune system. However, the efficacy of such treatments is limited, and novel therapeutic options for MG are urgently required. In the current review, a new therapeutic strategy is proposed based on the mitochondrial biogenesis and energy metabolism pathway, as stimulating mitochondrial biogenesis and the energy metabolism might alleviate myasthenia gravis. A number of cellular sensors of the energy metabolism were investigated, including AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). AMPK and SIRT1 are sensors that regulate cellular energy homeostasis and maintain energy metabolism by balancing anabolism and catabolism. Peroxisome proliferator-activated receptor γ coactivator 1α and its downstream transcription factors nuclear respiratory factors 1, nuclear respiratory factors 2, and transcription factor A are key sensors of mitochondrial biogenesis, which can restore mitochondrial DNA and produce new mitochondria. These processes help to control muscle contraction and relieve the symptoms of MG, including muscle weakness caused by dysfunctional NMJ transmission. Therefore, the present review provides evidence for the therapeutic potential of targeting mitochondrial biogenesis for the treatment of MG.

Administration of isoliquiritigenin prevents nonalcoholic fatty liver disease through a novel IQGAP2-CREB-SIRT1 axis

Isoliquiritigenin (ISO) is a flavonoid extracted from the root of licorice, which serves various biological and pharmacological functions including antiinflammatory, antioxidation, liver protection, and heart protection. However, the mechanism of its action remains elusive and the direct target proteins of ISO have not been identified so far. Through cell-based screening, we identified ISO as a potent lipid-lowering compound. ISO treatment successfully ameliorated fatty acid-induced cellular lipid accumulation and improved nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) by increasing PPARα-dependent lipid oxidation and decreasing SREBPs-dependent lipid synthesis. Both these signaling required the activation of SIRT1. Knockdown of SIRT1 resulted in the reversal of ISO beneficiary effects suggesting that the lipid-lowering activity of ISO was regulated by SIRT1 expression. To identify the direct target of ISO, limited proteolysis combined with mass spectrometry (LiP-SMap) strategy was applied and IQGAP2 was identified as the direct target for ISO in regulating lipid homeostasis. In the presence of ISO, both mRNA and protein levels of SIRT1 were increased; however, this effect was abolished by blocking IQGAP2 expression using siRNA. To explore how IQGAP2 regulated the expression level of SIRT1, proteome profiler human phospho-kinase array kit was used to reveal possible phosphorylated kinases and signaling nodes that ISO affected. We found that through phosphorylation of CREB, ISO transduced signals from IQGAP2 to upregulate SIRT1 expression. Thus, we not only demonstrated the molecular basis of ISO in regulating lipid metabolism but also exhibited for the first time a novel IQGAP2-CREB-SIRT1 axis in treating NAFLD/NASH.

Sex hormone-like Effects of Icariin on T-cells immune modulation in spontaneously hypertensive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedium brevicornu Maxim as a Chinese herb, is recommended for the treatment of menopausal women with hypertension for 50 years. Icariin, as the main hydrophilic ingredient of Epimedium brevicornu Maxim, has been proven to be a plant sex hormone and lower blood pressure down. Here, we hypothesized that Icariin can regulate T cells differentiation which leads to the blood pressure decrease in castrated SHR rats.

AIM OF THE STUDY

The present study aimed to investigate the effects of the exogenous estrogen, androgen and Icariin on T-cell modulation in hypertension.

MATERIALS AND METHODS

Two weeks after castration, both male and female SHR rats were given estradiol, testosterone, and Icariin intervention respectively. Body weight, blood pressure, and heart rate were tested weekly. After six weeks, proportion of T helper cells (Th), cytotoxic T cells (Tc), and regulatory T cells (Tregs) in both peripheral blood mononuclear cells (PBMCs) and splenocytes were tested by flowcytometry. Serum levels of estrogen, testosterone, AngII, TNF-α, IL-17 were tested by Elisa. Aortic arches were isolated for HE and Masson staining. The expressions of ERβ and AR in aorta were tested by Western-blot.

RESULTS

In both male and female SHR rats, we found that Icariin and estradiol lower blood pressure, but testosterone elevates blood pressure. Similar as testosterone, Icariin can attenuate Tc and Th proportions and elevate Tregs proportion in both peripheral blood and splenocyte in male SHR, which can be blunt by flutamide. Besides, Icariin performs similar function as estradiol that attenuates Tc proportions and elevates Tregs proportion in both peripheral blood and splenocytes in female SHR, which leads to the lower blood pressure and can be partly blunt by fulvestrant. Testosterone increases AngII and TNF-α levels in serum, leading to the higher blood pressure in both male and female SHR rats.

CONCLUSION

These results verified that Icariin, as a plant sex hormone, can regulate T cells differentiation related to blood pressure decrease in SHR rats.

Icariin Treatment Protects Against Gentamicin-Induced Ototoxicity via Activation of the AMPK-SIRT3 Pathway

Ototoxicity is a serious health problem that greatly affects millions of people worldwide. This condition is caused by the entry of aminoglycosides into auditory hair cells, subsequently inducing reactive oxygen species (ROS) production and accumulation. Several strategies have been adopted to overcome irreversible ROS-induced hair cell loss in mammals. In recent years, icariin, a major active component of the traditional herb Epimedium, has been widely studied and revealed to have antioxidant, anti-inflammatory, and anti-apoptotic properties. In this study, we found that icariin pretreatment improved the survival rate of gentamicin-treated House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and cochlear explants. Icariin remarkably suppressed HEI-OC1 cell apoptosis and inhibited ROS production in cells. Notably, icariin upregulated PGC-1α (SIRT3 promoter) and SIRT3 expression in HEI-OC1 cells. In addition, SIRT3 inhibition significantly attenuated the anti-apoptotic effect of icariin. We also found that icariin can increase AMPK phosphorylation. Further studies showed that inhibition of SIRT3 activity had no significant effect on AMPK phosphorylation. Furthermore, the AMPK inhibitor compound C significantly suppressed SIRT3 expression, meaning that AMPK, as an upstream molecule, regulates SIRT3 expression. Meanwhile, inhibition of AMPK activity significantly reduced the protective effect of icariin on gentamicin ototoxicity. Based on these results, icariin exerts its protective effect on gentamicin-induced ototoxicity via activation of the AMPK-SIRT3 signaling pathway, thus providing a new strategy for treating ototoxicity caused by aminoglycoside antibiotics.

Astaxanthin ameliorates oxidative stress and neuronal apoptosis via SIRT1/NRF2/Prx2/ASK1/p38 after traumatic brain injury in mice

BACKGROUND AND PURPOSE

Oxidative stress and neuronal apoptosis play key roles in traumatic brain injury. We investigated the protective effects of astaxanthin against traumatic brain injury and its underlying mechanisms of action.

EXPERIMENTAL APPROACH

A weight-drop model of traumatic brain injury in vivo and hydrogen peroxide exposure in vitro model were established. Brain oedema, behaviour tests, western blot, biochemical analysis, lesion volume, histopathological study and cell viability were performed.

KEY RESULTS

Astaxanthin significantly reduced oxidative insults on Days 1, 3 and 7 after traumatic brain injury. Neuronal apoptosis was also ameliorated on Day 3. Additionally, astaxanthin improved neurological functions up to 3 weeks after traumatic brain injury. Astaxanthin treatment dramatically enhanced the expression of peroxiredoxin 2 (Prx2), nuclear factor-erythroid 2-related factor 2 (NRF2/Nrf2) and sirtuin 1 (SIRT1), while it down-regulated the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1) and p38. Inhibition of Prx2 by siRNA injection reversed the beneficial effects of astaxanthin against traumatic brain injury. Additionally, Nrf2 knockout prevented the neuroprotective effects of astaxanthin in traumatic brain injury. In contrast, overexpression of Prx2 in Nrf2 knockout mice attenuated the secondary brain injury after traumatic brain injury. Moreover, inhibiting SIRT1 by EX527 dramatically inhibited the neuroprotective effects of astaxanthin and suppressed SIRT1/Nrf2/Prx2/ASK1/p38 pathway both in vivo and in vitro.

CONCLUSION AND IMPLICATIONS

Astaxanthin improved the neurological functions and protected the brain from injury after traumatic brain injury, primarily by reducing oxidative stress and neuronal death via SIRT1/Nrf2/Prx2/ASK1/p38 signalling pathway and might be a new candidate to ameliorate traumatic brain injury.

A novel Danshensu/tetramethylpyrazine protects against Myocardial Ischemia Reperfusion Injury in rats

A new Danshensu/tetramethylpyrazine derivative (ADTM) with cardio-protection effects such as antioxidant, arterial relaxation, pro-angiogenesis and antiplatelet activities. Platelet activating factor receptor (PAFR) plays a key role in myocardial ischemia reperfusion (MIR) injury. This study aims to investigate the protective role of ADTM in MIR injury and clarify the potential role of PAFR. We measured the effects of ADTM on MIR injury in rats in vivo and hypoxia re-oxygenation (HR) injury in neonatal rat ventricular myocytes (NRVMs) in vitro. The results show that ADTM can significantly improve the IR-induced decline in heart function as increasing EF and FS, and restore the decreased cardiac hemodynamic parameters (LVSP, ± dp/dt max) and increased the level of LVEDP, decrease the infarct size of damaged myocardium and lactate dehydrogenase (LDH) activity in serum. Additionally, ADTM inhibits cardiomyocytes apoptosis, caspase-3 activity, and inflammatory response as well as down-regulates the MIR-induced IL-1β and TNFα production. Next, PAFR expression was significantly down-regulated in cardiomyocytes of MIR model in vivo and in vitro after treated with ADTM compare to IR group. At the same time, ADTM and PAFR small interfering RNA (siRNA) could inhibit cardiomyocytes apoptosis and inflammation during HR, while PAF presents the opposite effect. Furthermore, the above effects of PAF in HR induced cardiomyocytes were reversed by co-treatment of ADTM. Our findings demonstrate for the first time that ADTM protects against MIR injury through inhibition of PAFR signaling, which provides a new treatment for MIR.

Regulation of Mitochondrial Quality Control by Natural Drugs in the Treatment of Cardiovascular Diseases: Potential and Advantages

Mitochondria are double-membraned cellular organelles that provide the required energy and metabolic intermediates to cardiomyocytes. Mitochondrial respiratory chain defects, structure abnormalities, and DNA mutations can affect the normal function of cardiomyocytes, causing an imbalance in intracellular calcium ion homeostasis, production of reactive oxygen species, and apoptosis. Mitochondrial quality control (MQC) is an important process that maintains mitochondrial homeostasis in cardiomyocytes and involves multi-level regulatory mechanisms, such as mitophagy, mitochondrial fission and fusion, mitochondrial energy metabolism, mitochondrial antioxidant system, and mitochondrial respiratory chain. Furthermore, MQC plays a role in the pathological mechanisms of various cardiovascular diseases (CVDs). In recent years, the regulatory effects of natural plants, drugs, and active ingredients on MQC in the context of CVDs have received significant attention. Effective active ingredients in natural drugs can influence the production of energy-supplying substances in the mitochondria, interfere with the expression of genes associated with mitochondrial energy requirements, and regulate various mechanisms of MQC modulation. Thus, these ingredients have therapeutic effects against CVDs. This review provides useful information about novel treatment options for CVDs and development of novel drugs targeting MQC.