Effect of atorvastatin on expression of TLR4 and NF-κB p65 in atherosclerotic rabbits

Use of Statins in Heart Failure with Preserved Ejection Fraction: Current Evidence and Perspectives

Systemic inflammation and coronary microvascular endothelial dysfunction are essential pathophysiological factors in heart failure (HF) with preserved ejection fraction (HFpEF) that support the use of statins. The pleiotropic properties of statins, such as anti-inflammatory, antihypertrophic, antifibrotic, and antioxidant effects, are generally accepted and may be beneficial in HF, especially in HFpEF. Numerous observational clinical trials have consistently shown a beneficial prognostic effect of statins in patients with HFpEF, while the results of two larger trials in patients with HFrEF have been controversial. Such differences may be related to a more pronounced impact of the pleiotropic properties of statins on the pathophysiology of HFpEF and pro-inflammatory comorbidities (arterial hypertension, diabetes mellitus, obesity, chronic kidney disease) that are more common in HFpEF. This review discusses the potential mechanisms of statin action that may be beneficial for patients with HFpEF, as well as clinical trials that have evaluated the statin effects on left ventricular diastolic function and clinical outcomes in patients with HFpEF.

The amelioration of a purified Pleurotus abieticola polysaccharide on atherosclerosis in ApoE-/- mice

In this study, a polysaccharide known as PAPS2 was eluted from Pleurotus abieticola fruiting bodies using 0.1 M NaCl solutions. PAPS2 has a Mw of 19.64 kDa and its backbone is mainly composed of →6)-α-D-Galp-(1→, →6)-β-D-Glcp-(1→ and →2,6)-α-D-Galp-(1→ residues, and its branches mainly end with β-D-Manp-(1→, which is attached at C2 of →2,6)-α-D-Galp-(1→. PAPS2 elicited several effects in high-fat diet (HFD)-fed ApoE-/- mice. It significantly reduced the body weight, liver index, and serum levels of total cholesterol (TC) and triglycerides (TGs), and it alleviated lipid accumulation in the aorta. Intestinal microflora analysis showed that PAPS2 suppressed the abundances of Adlercreutzia, Turicibacter, and Helicobacter and enriched that of Roseburia. It also influenced lipid metabolism, suggesting that it reduced the levels of TGs, lysophosphatidylcholine (LPC), phosphatidylcholine (PC), and ceramide (Cer). Moreover, it suppressed oxidative response by increasing nuclear factor erythroid 2 (Nrf2)-related factor expression and activating the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) to reduce the level of reactive oxygen species (ROS). Meanwhile, it showed anti-inflammatory effects partially related to the inhibition of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling induced by lipopolysaccharide (LPS) in RAW 264.7 cells, as well as in the aorta of HFD-fed ApoE-/- mice. This study provides experimental evidence of the auxiliary applicability of PAPS2 in atherosclerosis treatment.

The Mechanism and Role of N6-Methyladenosine (m6A) Modification in Atherosclerosis and Atherosclerotic Diseases

N6-methyladenosine (m6A) modification is a newly discovered regulatory mechanism in eukaryotes. As one of the most common epigenetic mechanisms, m6A's role in the development of atherosclerosis (AS) and atherosclerotic diseases (AD) has also received increasing attention. Herein, we elucidate the effect of m6A on major risk factors for AS, including lipid metabolism disorders, hypertension, and hyperglycemia. We also describe how m6A methylation contributes to endothelial cell injury, macrophage response, inflammation, and smooth muscle cell response in AS and AD. Subsequently, we illustrate the m6A-mediated aberrant biological role in the pathogenesis of AS and AD, and analyze the levels of m6A methylation in peripheral blood or local tissues of AS and AD, which helps to further discuss the diagnostic and therapeutic potential of m6A regulation for AS and AD. In summary, studies on m6A methylation provide new insights into the pathophysiologic mechanisms of AS and AD, and m6A methylation could be a novel diagnostic biomarker and therapeutic target for AS and AD.

Role of statins in regulating molecular pathways following traumatic brain injury: A system pharmacology study

Traumatic brain injury (TBI) is a serious disorder with debilitating physical and psychological complications. Previous studies have indicated that genetic factors have a critical role in modulating the secondary phase of injury in TBI. Statins have interesting pleiotropic properties such as antiapoptotic, antioxidative, and anti-inflammatory effects, which make them a suitable class of drugs for repurposing in TBI. In this study, we aimed to explore how statins modulate proteins and pathways involved in TBI using system pharmacology. We first explored the target associations with statins in two databases to discover critical clustering groups, candidate hub and critical hub genes in the network of TBI, and the possible connections of statins with TBI-related genes. Our results showed 1763 genes associated with TBI. Subsequently, the analysis of centralities in the PPI network displayed 55 candidate hub genes and 15 hub genes. Besides, MCODE analysis based on threshold score:10 determined four modular clusters. Intersection analysis of genes related to TBI and statins demonstrated 204 shared proteins, which suggested that statins influence 31 candidate hub and 9 hub genes. Moreover, statins had the highest interaction with MCODE1. The biological processes of the 31 shared proteins are related to gene expression, inflammation, antioxidant activity, and cell proliferation. Biological enriched pathways showed Programmed Cell Death proteins, AGE-RAGE signaling pathway, C-type lectin receptor signalling pathway, and MAPK signaling pathway as top clusters. In conclusion, statins could target several critical post-TBI genes mainly involved in inflammation and apoptosis, supporting the previous research results as a potential therapeutic agent.

A new polysaccharide from Caulerpa chemnitzia induces molecular shifts of immunomodulation on macrophages RAW264.7

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CCP showed significant immunomodulatory effects.

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CCP raising the level of NO, TNF-α, and IL-6 of macrophages RAW264.7.

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Investigation on the metabolites and genes changes in CCP-induced RAW264.7.

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Potential immunostimulatory mechanism of CCP on RAW264.7 was elucidated.

Investigation on Caulerpa chemnitzia polysaccharides led to the finding of a new polysaccharide (CCP). The basic components of CCP were the total sugar (59.18% ± 0.57%), the uronic acids (36.75% ± 0.28%) and the sulfate (42.50% ± 0.42%), in total content. The physicochemical analysis revealed that CCP was a heteropolysaccharide with a molecular weight of 321.6 KDa, and composed of arabinose, fucose, glucose, mannose, galactose, xylose, fructose, ribose, glucuronic acid and galacturonic acid. The immunomodulatory assay showed that CCP played an important role in activating cell viability, the nitric oxide product and cytokines (IL-6 and TNF-α) secretion. Furthermore, the transcript-metabolic analysis displayed a total of 7692 differentially expressed genes (DEGs) and 95 differentially accumulated metabolites (DAMs), and revealed that CCP may play an immunomodulatory effect by activating NF-κB signaling pathway and arachidonic acid metabolism pathway. These findings will provide a basic understanding to further investigation of Caulerpa polysaccharides.

The Traditional Chinese Medicine Hua Tuo Zai Zao Wan Alleviates Atherosclerosis by Deactivation of Inflammatory Macrophages

Introduction

Positive effects have been observed when the traditional Chinese medicine Hua Tuo Zai Zao Wan (HTZZW) has been used for the treatment of atherosclerosis (AS), although with an unclear mechanism.

Methods

ApoE-/- C57/BALB mice were used to determine the efficacy of HTZZW by blood lipid biochemical analysis and histopathology H&E staining. qPCR and western blot were used to determine the expression of METTL3/14 and NF-κB.

Results

High-fat diet-fed ApoE-/- mice that consumed HTZZW exhibited significantly smaller plaque areas and significantly decreased unstable collagen areas in the aortic arch as well as significantly lower blood levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol compared with the control group. Consumption of HTZZW significantly decreased the proportion of Mφ1 in the peripheral blood. HTZZW not only inhibited the expression of m6A methyltransferases METTL14, METTL3, and overall RNA methylation level, but it also decreased the m6A modification level on specific sites of NF-κB mRNA.

Conclusion

HTZZW significantly alleviated the progression of AS by regulating the expression of the m6A methyltransferases METTL14 and METTL3 in macrophages, eliminating m6A modifications of NF-κB mRNA, influencing the stability of NF-κB mRNA, and ultimately resulting in the deactivation of inflammatory macrophages.

The Effect of Statins through Mast Cells in the Pathophysiology of Atherosclerosis: a Review

PURPOSE OF REVIEW

In this review, we discuss the evidence supporting the effects of statins on mast cells (MCs) in atherosclerosis and their molecular mechanism of action.

RECENT FINDINGS

Statins or HMG-CoA reductase inhibitors are known for their lipid-lowering properties and are widely used in the prevention and treatment of cardiovascular diseases. There is growing evidence that statins have an inhibitory effect on MCs, which contributes to the pleiotropic effect of statins in various diseases. MCs are one of the crucial effectors of the immune system which play an essential role in the pathogenesis of multiple disorders. Recent studies have shown that MCs are involved in the development of atherosclerotic plaques. MCs secrete various inflammatory cytokines (IL-6, IL4, TNF-α, and IFNγ) and inflammatory mediators (histamine, tryptase, proteoglycans) after activation by various stimulants. This, in turn, will exacerbate atherosclerosis. Statins suppress the activation of MCs via IgE inhibition which leads to inhibition of inflammatory mediators and cytokines which are involved in the development and progression of atherosclerosis. In keeping with this evidence presented here, MCs can be considered as one of the therapeutic targets for statins in the treatment of atherosclerosis.

Anti-inflammatory Action of Statins in Cardiovascular Disease: the Role of Inflammasome and Toll-Like Receptor Pathways

Atherosclerosis is one type of cardiovascular disease (CVD) in which activation of the NLRP3 inflammasome and toll-like receptor (TLR) pathways is implicated. One of the most effective treatments for atherosclerosis is the use of statin medications. Recent studies have indicated that statins, in addition to their lipid-lowering effects, exert inhibitory and/or stimulatory effects on the NLRP3 inflammasome and TLRs. Some of the statins lead to activation of the inflammasome and subsequently cause secretion of IL-1β and IL-18. Thus, these actions may further aggravate the disease. On the other hand, some statins cause inhibition of the inflammasome or TLRs and along with lipid-lowering, help to improve the disease by reducing inflammation. In this article, we discuss these contradictory studies and the mechanisms of action of statins on the NLRP3 inflammasome and TLR pathways. The dose-dependent effects of statins on the NLRP3 complex are related to their chemistry, pharmacokinetic properties, and danger signals. Lipophilic statins have more pleiotropic effects on the NLRP3 complex in comparison to hydrophilic statins. Statins can suppress TLR4/MyD88/NF-ĸB signaling and cause an immune response shift to an anti-inflammatory response. Furthermore, statins inhibit the NF-ĸB pathway by decreasing the expression of TLRs 2 and 4. Statins are cost-effective drugs, which should have a continued future in the treatment of atherosclerosis due to both their immune-modulating and lipid-lowering effects.

Effects of ABCG2 and SLCO1B1 gene variants on inflammation markers in patients with hypercholesterolemia and diabetes mellitus treated with rosuvastatin

PURPOSE

Dysregulation of angiogenesis and inflammation play important roles in the development of atherosclerosis. Rosuvastatin (RST) was widely used in atherosclerosis therapy. Genetic variations of transporters may affect the rosuvastatin concentration in plasma and reflect different clinical treatment. The aim of this study was to explore the drug transport related single-nucleotide polymorphisms (SNPs) on RST pharmacokinetic and the further on pro-angiogenic and pro-inflammatory factors.

METHODS

A total of 269 Chinese patients with hypercholesterolemia and diabetes mellitus were enrolled. They were treated with RST to lower cholesterol. The plasma concentration of RST was determined using a validated UPLC-MS/MS method. Seven single-nucleotide polymorphisms (SNPs) in six genes were genotyped using the Sanger dideoxy DNA sequencing method. The serum concentrations of inflammation markers were determined using ELISA kits.

RESULTS

ABCG2 421C > A (rs2231142) and SLCO1B1 521 T > C (rs4149056) variations were highly associated with plasma concentrations of RST (P < 0.01, FDR < 0.05). The serum MCP-1, sVCAM-1, and TNF-α levels were significantly different between the ABCG2 421C > A and SLCO1B1 521 T > C genetic variation groups (P < 0.01). RST concentration was negatively correlated with sVCAM-1 concentration (r = 0.150, P = 0.008).

CONCLUSION

ABCG2 421C > A (rs2231142) and SLCO1B1 521 T > C (rs4149056) genetic variants affect RST concentration significantly and potentially affect serum levels of pro-inflammatory and pro-angiogenic markers. The effects on anti-inflammation might not be related to high plasma exposure of RST.

Fufang-Zhenzhu-Tiaozhi Capsule reduces restenosis via the downregulation of NF-kappaB and inflammatory factors in rabbits

BACKGROUND

To investigate the effects of a Chinese herbal medicine Fufang-Zhenzhu Tiaozhi Capsule (FTZ) on restenosis and elucidate the mechanism of action.

METHODS

A restenosis model was established by balloon rubbing the endothelium of the abdominal aorta followed by high fat diet. Rabbits were divided into blank control group, restenosis group, FTZ group (0.66 mg/kg/day), atorvastatin group (5 mg/kg/day) and FTZ + atorvastatin group (n = 8). Vascular stenosis was analyzed by X-ray. Serum levels of chemokines and cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-12 (IL-12), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) were measured by ELISA. The levels of NF-κB, IκB-α, P-IκBα, IKK-α, and P-IKKα/β from injured abdominal arteries were detected by Western blotting.

RESULTS

Restenosis was induced successfully via abdominal artery balloon injuries and high fat diet. Restenosis was significantly decreased in FTZ group compared with restenosis group (P < 0.05). FTZ group had markedly reduced serum lipid levels (P < 0.05). In addition, the levels of TNF-α, IL-1, IL-6, IL-8, IL-12, ICAM-1 and MCP-1 decreased by FTZ treatment (P < 0.05). The expression of NF-κB in the atherosclerotic lesions was significantly attenuated in FTZ group (P < 0.05).

CONCLUSION

FTZ could reduce restenosis via reducing NF-κB activity and inflammatory factor expression within the atherosclerotic lesion in a rabbit restenosis model. FTZ may be a new therapeutic agent for restenosis.

Effects of atorvastatin and/or probucol on recovery of atherosclerosis in high-fat-diet-fed apolipoprotein E-deficient mice

INTRODUCTION

We have investigated the possible effects and mechanism of atorvastatin, a statin, and/or probucol, a powerful antioxidant used to lower cholesterol before 1995, on the atherosclerosis development.

METHODS

Apolipoprotein-E-deficient (ApoE^-/-) mice fed with the high fat diet were randomly divided into 3 groups (n = 10/each group): Placebo, Atorvastatin (10 mg/ kg/d), and atorvastatin (10 mg/kg/d) plus probucol (10 mg/kg/d) groups. C57BL/6 J mice were fed with normal diet as the control group (n = 10). Animals were sacrificed 10 weeks after the intervention. To evaluate the experimental atherosclerosis, blood tests were used for measuring serum lipoprotein profile, Western blots for endoplasmic reticulum (ER) stress protein expression, H&E staining for plaque lesions, immunohistology for macrophages, inflammatory cytokines, innate immune receptor TLR-4, transcription factor NF-κB, and atherosclerosis plaques.

RESULTS

Compared with the control group, ApoE^-/- mice in the placebo group showed with the significantly (p < 0.05) higher levels of serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL) and oxidized low density lipoprotein (ox-LDL), PERK, GRP78, CHOP, IL-1β, TNF-α and NF-κB, but with the lower levels of high-density lipoprotein cholesterol (HDL) and TLR-4, and also the increase in macrophages and the aortic media collagen, and the decrease in the elastic fibers (p < 0.01). Treatment with atorvastatin recovered all these features (p < 0.05 or p < 0.01) near to the levels in the control group. In addition, the combination of atorvastatin and probucol has shown the slightly stronger effect than the use of atorvastatin alone without statistical significances when comparing most bio-markers of atherosclerosis, but with significant differences in the reduction of the plaque lesion areas and macrophages (p < 0.05).

CONCLUSIONS

Atorvastatin and/or probucol suppresses ER stress and increase the level of TLR-4, which lowers NF-κB, resulting in the recovery of atherosclerosis in the ApoE^-/- mouse model.

Effect of statins on toll-like receptors: a new insight to pleiotropic effects

The toll-like receptors (TLRs) are a class of transmembrane-spanning receptors that are sentinels of both innate and adaptive immunity. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are the most commonly prescribed therapeutic agents for treating hypercholesterolemia globally. However, statin therapy appears to have pleiotropic effects including attenuation of chronic low-grade inflammation and modulation of TLR activity. Statins through abolition of TLR4 expression and regulation of the TLR4/Myd88/NF-κB signaling pathway may slow the progression of atherosclerosis and other inflammatory diseases. In this review, we have focused on the impact and mechanism of action of statins on cardiovascular and non-cardiovascular diseases.

Effects of Tianxiangdan Granule treatment on atherosclerosis via NF‑κB and p38 MAPK signaling pathways

The present study aimed to determine the effects of Tianxiangdan Granule on nuclear factor (NF)-κB p65 and p38 mitogen-activated protein kinase (MAPK) inflammatory signaling pathways, and explored the possible mechanism underlying the effects of Tianxiangdan Granule on prevention and treatment of atherosclerosis. A total of 48 apolipoprotein E^−/− mice (age, 8 weeks) were selected and divided into two groups: The normal control group (n=12) and the modeling group (n=36). In the modeling group, mice were fed a high-fat diet and were maintained in an artificial climate box, in order to stimulate the climate and eating habit characteristics of Xinjiang. Every morning, ApoE−/− mice in the modeling group were placed in the artificial climate box at 10:00 am and were taken out at 09:00 pm and placed back in the room temperature environment. The temperature of the artificial climate box was set at 6±2°C, relative humidity was controlled at 25–32.8% and the light-dark cycle was 12 h/day. The purpose of this method was to establish the Huizhuo Tanzu type atherosclerosis model. Following successful generation of the model, mice in the modeling group were randomly divided into three groups: Model group (n=10), Tianxiangdan group (n=10) and atorvastatin group (n=10). After 12 weeks, mice were sacrificed and the serum levels of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in each group were detected. Furthermore, the expression levels of NF-κB p65 and p38 MAPK in aortic tissue were detected. The results indicated that the concentrations of IL-1β and TNF-α were significantly higher in mice in the model group compared with in the normal control group (P<0.01), whereas the concentrations of IL-1β and TNF-α were lower in the Tianxiangdan and atorvastatin groups compared with in the model group (P<0.01). Furthermore, the protein expression levels of phosphorylated (p)-NF-κB p65 and p-p38 MAPK protein were higher in aortic tissues from the model group compared with in the normal control group (P<0.01), p-NF-κB p65 and p-p38 MAPK protein expression was reduced in the atorvastatin and Tianxiangdan groups compared with in the model group. The present study indicated that the mechanism underlying the effects of Tianxiangdan Granule on the prevention and treatment of atherosclerosis may be as follows: Tianxiangdan Granule may decrease the expression of the inflammatory cytokines IL-1β and TNF-α, and suppress activation of the NF-κB p65 and p38 MAPK signaling pathways.

Curcumin modulates covalent histone modification and TIMP1 gene activation to protect against vascular injury in a hypertension rat model

Hypertension is a leading risk factor for morbidity and mortality. Previous studies have reported that curcumin has anti-oxidation and anti-aging effects and inhibits histone deacetylase activity. However, it is still unclear whether curcumin could protect against vascular injury induced by hypertension. Thus, the current study examined the therapeutic effects and mechanism of curcumin on vascular injury induced by hypertension in spontaneous hypertensive rats (SHRs). The present study revealed that curcumin may improve vascular structure and attenuate coronary artery pathology. Moderate doses (~50 mg) of curcumin were most effective in treating coronary artery injury in SHRs. Moreover, the results of immunohistochemical analysis indicated that the expression levels of histone deacetylase 1 (HDAC1), matrix metalloproteinase-2 (MMP-2) and transforming growth factor β (TGFβ) decreased in the curcumin treatment group, compared with the non-treated group or the negative control group. However, the expression of tissue inhibitor of metalloproteinase 1 (TIMP1) did not visibly decrease. Furthermore, chromatin immunoprecipitation results suggested that curcumin was capable of promoting the transcription activation of TIMP1 through suppressing HDAC1 expression and increasing histone H3 acetylation at the TIMP1 promoter region in SHRs. In conclusion, curcumin could relieve extracellular matrix degradation and interstitial fibrosis induced by hypertension, and lower blood pressure. It could also serve a function in improving vascular structure through inhibiting the expression of HDAC1, thereby promoting TIMP1 transcription activation and suppressing the expression of MMP-2 and TGFβ.

Different cardiometabolic effects of atorvastatin in men with normal vitamin D status and vitamin D insufficiency

BACKGROUND

Vitamin D is suggested to reduce cardiovascular risk.

HYPOTHESIS

Circulating levels of plasma lipids and other cardiovascular risk factors may differ between statin-treated patients with different vitamin D status.

METHODS

We studied 3 age- and weight-matched groups of men with elevated low-density lipoprotein cholesterol (LDL-C) levels: vitamin D-naïve men with vitamin D insufficiency (group A, n = 18), men with vitamin D deficiency/insufficiency effectively treated with vitamin D preparations (group B, n = 16), and vitamin D-naïve men with normal vitamin D status (group C, n = 16). All patients were then treated with atorvastatin (20 mg daily) for 4 months. Plasma lipids, glucose homeostasis markers, and plasma levels of uric acid, high-sensitivity C-reactive protein (hsCRP), homocysteine, and fibrinogen were assessed before and at the end of atorvastatin therapy.

RESULTS

Study groups did not differ in baseline levels of plasma lipids. Men with vitamin D deficiency or insufficiency effectively treated with vitamin D preparations were characterized by decreased insulin sensitivity and higher circulating levels of hsCRP, homocysteine, and fibrinogen in comparison with the remaining groups of patients. Although atorvastatin decreased plasma levels of total cholesterol and LDL-C to a similar extent in all study groups, its effect on uric acid, hsCRP, homocysteine, and fibrinogen was more pronounced in patients from groups B and C than in men from group A. Moreover, in patients with vitamin D insufficiency, atorvastatin impaired insulin sensitivity.

CONCLUSIONS

The obtained results indicate that the strength of pleiotropic effects of atorvastatin depends on vitamin D status.

Growth hormone treatment of premature ovarian failure in a mouse model via stimulation of the Notch-1 signaling pathway

Premature ovarian failure (POF) is a condition affecting 1% of women in the general population, causing amenorrhea, hypergonadotropism and hypoestrogenism before the age of 40. Currently, POF cannot be reversed and, although treatments are available, there is an urgent need for improved treatment strategies. Growth hormone (GH) is a pleiotropic hormone that affects a broad spectrum of physiological functions, from carbohydrate and lipid metabolism to the immune response. GH has previously been used to treat POF in non-transgenic preclinical trials, but the biochemical mechanism underlying these effects are unclear. In the present study, a mouse model of POF was generated using cyclophosphamide. Treatment of POF mice with recombinant mouse growth hormone (rmGH) was revealed to markedly reduce POF histopathology in ovarian tissue, relieve ovarian granulosa cell injury, reduce the number of atretic follicles and significantly increase the number of mature oocytes. Furthermore, an enzyme-linked immunosorbent assay revealed that plasma estradiol levels increased and plasma follicle stimulating hormone levels decreased with time in a group of mice treated with a medium dose of rmGH (0.8 mg/kg) when compared with the POF model group (P<0.05). In addition, reverse transcription-quantitative polymerase chain reaction and immunohistochemical analysis demonstrated elevated levels of Notch-1 signaling pathway factors (Notch1, CBF1, and HES1) in wild-type mice and those treated with medium and high doses of rmGH, but not in those treated with low doses of rmGH. In conclusion, GH may promote ovarian tissue repair, estrogen release and oocyte maturation via activation of the Notch-1 signaling pathway in ovarian tissue.

Low temperature induces cryoinjury in mouse corneal endothelial cells by stimulating the Stk11-p53 signal pathway

Cryoinjury, or injury caused by extremely low temperatures, can occur in corneal endothelial cells (CECs) and lead to visual impairment. However, the mechanism of cryoinjury in CECs is not clear. The Stk11-p53 signaling pathway regulates the proliferation and division of cells. Activity of the Stk11-p53 signaling pathway arrests the cell cycle at the G0/G1 phase and induces apoptosis. In this study, a mouse model of cryoinjury in CECs was used. Following injury, significant mouse CEC death and shedding were observed. In addition, the mRNA and protein levels of core factors from the Stk11-p53 signaling pathway (Stk11, p21 and p53) were elevated and Caspase-3 was activated following cryoinjury. In addition, chromatin immunoprecipitation revealed that Stk11 catalyzed p53 serine 15 phosphorylation, and the Stk11-p53 complex bound to the p21 promoter and stimulated gene transcription. Thus, the results of the present study suggest that cryoinjury leads to the damage and apoptosis of mouse CECs by activation of the Stk11-p53 signaling pathway, phosphorylation of p53 serine 15 and p21 gene transcription.

Efficacy of atorvastatin on hippocampal neuronal damage caused by chronic intermittent hypoxia: Involving TLR4 and its downstream signaling pathway

Hippocampal neuronal damage is critical for the initiation and progression of neurocognitive impairment accompanied obstructive sleep apnea syndrome (OSAS). Toll-like receptor 4 (TLR4) plays an important role in the development of several hippocampus-related neural disorders. Atorvastatin was reported beneficially regulates TLR4. Here, we examined the effects of atorvastatin on hippocampal injury caused by chronic intermittent hypoxia (CIH), the most characteristic pathophysiological change of OSAS. Mice were exposed to intermittent hypoxia with or without atorvastatin for 4 weeks. Cell damage, the expressions of TLR4 and its two downstream factors myeloid differentiation factor 88 (MYD88) and TIR-domain-containing adapter-inducing interferon-β (TRIF), inflammatory agents (tumor necrosis factor α and interleukin 1β), and the oxidative stress (superoxide dismutase and malondialdehyde) were determined. Atorvastatin decreased the neural injury and the elevation of TLR4, MyD88, TRIF, pro-inflammatory cytokines and oxidative stress caused by CIH. Our study suggests that atorvastatin may attenuate CIH induced hippocampal neuronal damage partially via TLR4 and its downstream signaling pathway.

Tripterygium glycosides induce premature ovarian failure in rats by promoting p53 phosphorylation and activating the serine/threonine kinase 11-p53-p21 signaling pathway

Premature ovarian failure (POF) is a typical pathological disease of the reproductive system in aging females. Infection, inflammation, immune abnormalities, genetic mutation, radiotherapy and chemotherapy can cause POF. Tripterygium glycosides (TGs) are a component extracted from the Chinese herb Tripterygium wilfordii Hook. f., also known as Huangteng. Although TGs have been used to treat various diseases, drug resistance and toxicity can affect patients. The aim of the present study was to investigate the mechanism of TG-induced POF in rats. The rats were treated with different concentrations of TG, and pathology assays showed that the TG-induced POF was predominantly composed of interstitial cells in a fibrous matrix with a reduced number of follicles at each stage and an increased number of collapsed oocytes. Furthermore, reverse transcription-quantitative polymerase chain reaction (PCR) and immunohistochemistry assays indicated that the expression levels of serine/threonine kinase 11 (Stk11), p53 p21 and activated caspase-3 were elevated significantly in the TG-treated groups. Serine 15 phosphorylation of p53 was also enhanced significantly in the TG-treated groups. In addition, a chromatin immunoprecipitation-PCR assay revealed that the TGs induced p53 activation and enhanced the transcription of p21. In conclusion, TGs induce apoptosis and necrosis in rat ovarian tissues, as well as POF, via p53 phosphorylation and activation of the Stk11-p53-p21 signaling pathway.

MicroRNA-17 promotes normal ovarian cancer cells to cancer stem cells development via suppression of the LKB1-p53-p21/WAF1 pathway

The mechanism underlying the development of human ovarian cancer is poorly understood. The liver kinase protein, LKB1, is hypothesized to play a pivotal role in tumor cell proliferation and invasion capacity through regulation of p53 and p21/WAF1 expression. Previous studies suggest LKB1 may, in turn, be regulated by microRNA-17. Here, we examined the role of miR-17 in the expression of LKB1 and the downstream effects on proliferation and invasion capacity of normal ovarian cancer cells (OCCs) and ovarian stem cells. In this study, both the mRNA and protein expression levels of LKB1, p53, and p21 decreased in OCCs following transfection with a miR-17 expression plasmid. MiR-17 expression affected cell cycle regulation and stimulated the proliferation and invasion capacity of OCCs in vitro. ChIP assays indicated that the binding efficiency of p53 to the p21/WAF1 gene promoter was much lower in miR-17 transfected OCCs than in OCCs transfected with a mutated miR-17. Co-immunoprecipitation and western blotting showed significantly lower levels of p53 and p53 Ser15-pho in the miR-17 transfected OCCs as compared to the mutant miR-17 transfected OCCs. Xenograft experiments confirmed that suppression of tumor growth in vivo occurred in the absence of functional miR-17. These findings suggest that mature miR-17 expression may have an important role in the pathogenesis of human ovarian tumors through its interference with the LKB1-p53-p21/WAF1 pathway expression by epigenetic modification. These findings are of potential importance in the identification of novel therapeutic targets in human ovarian cancer.

Melatonin ameliorates vascular endothelial dysfunction, inflammation, and atherosclerosis by suppressing the TLR4/NF-κB system in high-fat-fed rabbits

Vascular endothelial dysfunction (VED) and inflammation contribute to the initiation and progression of atherosclerosis. Melatonin (MLT) normalizes lipid profile, improves endothelial function, and possesses anti-inflammatory properties. However, the precise mechanisms are still unclear. This study investigated whether MLT could ameliorate VED, inflammation, and atherosclerosis by suppressing the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) system in high-fat-fed rabbits. Rabbits were randomly divided into three groups that received a standard diet (control group), high-cholesterol diet (atherosclerosis group), or high-cholesterol diet plus 10 mg/kg/day MLT (MLT group) for 12 wk. After treatment, high-fat diet significantly increased serum lipid and inflammatory markers in rabbits in atherosclerosis group compared with that in control group. In addition, high-fat diet also induced VED and typical atherosclerotic plaque formation and increased intima/media thickness ratio, which were significantly improved by MLT therapy as demonstrated in MLT group. Histological and immunoblot analysis further showed that high-fat diet enhanced the expressions of TLR4, myeloid differentiation primary response protein (MyD88), and NF-κB p65, but decreased inhibitor of NF-κB (IκB) expression. By contrast, MLT therapy decreased the expressions of TLR4, MyD88, and NF-κB p65 and increased IκB expression. This study has demonstrated that MLT ameliorates lipid metabolism, VED, and inflammation and inhibits the progression of atherosclerosis in high-fat-fed rabbits. Moreover, our study indicates for the first time that suppression of the TLR4/NF-κB system in local vasculature with atherosclerotic damage is important for the protective effects of MLT.