Vitamin D and Atherosclerosis: Unraveling the Impact on Macrophage Function.

Vitamin D plays a crucial role in preventing atherosclerosis and in the regulation of macrophage function. This review aims to provide a comprehensive summary of the clinical evidence regarding the impact of vitamin D on atherosclerotic cardiovascular disease, atherosclerotic cerebrovascular disease, peripheral arterial disease, and associated risk factors. Additionally, it explores the mechanistic studies investigating the influence of vitamin D on macrophage function in atherosclerosis. Numerous findings indicate that vitamin D inhibits monocyte or macrophage recruitment, macrophage cholesterol uptake, and esterification. Moreover, it induces autophagy of lipid droplets in macrophages, promotes cholesterol efflux from macrophages, and regulates macrophage polarization. This review particularly focuses on analyzing the molecular mechanisms and signaling pathways through which vitamin D modulates macrophage function in atherosclerosis. It claims that vitamin D has a direct inhibitory effect on the formation, adhesion, and migration of lipid-loaded monocytes, thus exerting anti-atherosclerotic effects. Therefore, this review emphasizes the crucial role of vitamin D in regulating macrophage function and preventing the development of atherosclerosis.

GPR30 selective agonist G-1 induced insulin resistance in ovariectomized mice on high fat diet and its mechanism.

BACKGROUND: Previous in vivo and in vitro studies have demonstrated that estrogen receptor agonist G-1 regulates glucose and lipid metabolism. This study focused on the effects of G-1 on cardiometabolic syndrome and anti-obesity under a high fat diet (HFD). METHODS: Bilateral ovariectomized female mice were fed an HFD for 6 weeks, and treated them with G-1. A cardiomyocyte insulin resistance model was used to simulate the in vivo environment. The main outcome measures were blood glucose, body weight, and serum insulin levels to assess insulin resistance, while cardiac function and degree of fibrosis were assessed by cardiac ultrasound and pathological observations. We also examined the expression of p-AMPK, p-AKT, and GLUT4 in mice hearts and in vitro models to explore the mechanism by which G-1 regulates insulin signaling. RESULTS: G-1 reduced body weight in mice on an HFD, but simultaneously increased blood glucose and promoted insulin resistance, resulting in myocardial damage. This damage included disordered cardiomyocytes, massive accumulation of glycogen, extensive fibrosis of the heart, and thickening of the front and rear walls of the left ventricle. At the molecular level, G-1 enhances gluconeogenesis and promotes glucose production by increasing the activity of pyruvate carboxylase (PC) while inhibiting GLUT4 translocation via the AMPK/TBC1D1 pathway, thereby limiting glucose uptake. CONCLUSION: Despite G-1's the potential efficacy in weight reduction, the concomitant induction of insulin resistance and cardiac impairment in conjunction with an HFD raises significant concerns. Therefore, comprehensive studies of its safety profile and effects under specific conditions are essential prior to clinical use.

Fisetin Suppresses Atherosclerosis by Inhibiting Ferroptosis-Related Oxidative Stress in Apolipoprotein E Knockout Mice.

INTRODUCTION: Fisetin has been demonstrated to inhibit the occurrence of atherosclerosis; however, the mechanism of fisetin suppressing atherosclerosis remains elusive. METHODS: The function of fisetin in the inhibition of atherosclerosis was evaluated by hematoxylin and eosin and Oil Red O staining in ApoE-/- mice. Molecular biomarkers of atherosclerosis progression were detected by Western blot and qPCR. Moreover, the inhibition of atherosclerosis on oxidative stress and ferroptosis was evaluated by immunofluorescence staining, qPCR, and Western blot assays. RESULTS: The obtained results showed that serum lipid was attenuated and consequentially the formation of atherosclerosis was also suppressed by fisetin in ApoE-/- mice. Exploration of the mechanism revealed that molecular biomarkers of atherosclerosis were decreased under fisetin treatment. The level of reactive oxygen species and malondialdehyde declined, while the activity of superoxide dismutases and glutathione peroxidase was increased under the fisetin treatment. Additionally, the suppressor of ferroptosis, glutathione peroxidase 4 proteins, was elevated. The ferritin was decreased in the aortic tissues treated with fisetin. CONCLUSIONS: In summary, fisetin attenuated the formation of atherosclerosis through the inhibition of oxidative stress and ferroptosis in the aortic tissues of ApoE-/- mice.

Metformin alleviates bevacizumab-induced vascular endothelial injury in mice through growth differentiation factor 15 upregulation.

Objectives: Bevacizumab is a commonly used anticancer drug in clinical practice, but it often leads to adverse reactions such as vascular endothelial damage, hypertension, arterial and venous thrombosis, and bleeding. This study investigated the protective effects of metformin against bevacizumab-induced vascular injury in a mouse model and examined the possible involvement of GDF15/PI3K/AKT/FOXO/PPARγ signaling in the effects. Materials and Methods: C57 male mice were purchased. To investigate metformin, the mice were assigned to the saline, bevacizumab (15 mg every 3 days), metformin (1200 mg/day), and bevacizumab+metformin groups. To investigate GDF15, the mice were assigned to the siNC+bevacizumab, siNC+bevacizumab+metformin, siGDF15+bevacizumab, and siGDF15+bevacizumab+metformin groups. Histological staining was used to evaluate vascular injury. Flow cytometry was used to evaluate apoptosis. ELISA was used to measure plasma endothelial injury markers and proinflammatory cytokines. qRT-PCR and western blot were used to determine the expression of GDF15 and PI3K/AKT/FOXO/PPARγ in aortic tissues. Results: Metformin alleviated bevacizumab-induced abdominal aortic injury, endothelial cell apoptosis, and systemic inflammation in mice (all P<0.05). Metformin up-regulated GDF15 expression and PI3K/AKT/FOXO/PPARγ signaling in the abdominal aorta of mice treated with bevacizumab (all P<0.05). siGDF15 abolished the vascular protective and anti-inflammatory effects of metformin (all P<0.05). siGDF15 suppressed PI3K/AKT/FOXO/PPARγ signaling in the abdominal aorta of mice treated with bevacizumab (all P<0.05). Conclusion: Metformin attenuates bevacizumab-induced vascular endothelial injury, apoptosis, and systemic inflammation by activating GDF15/PI3K/AKT/FOXO/PPARγ signaling.

Clusterin is a Potential Therapeutic Target in Alzheimer's Disease.

In recent years, Clusterin, a glycosylated protein with multiple biological functions, has attracted extensive research attention. It is closely associated with the physiological and pathological states within the organism. Particularly in Alzheimer's disease (AD) research, Clusterin plays a significant role in the disease's occurrence and progression. Numerous studies have demonstrated a close association between Clusterin and AD. Firstly, the expression level of Clusterin in the brain tissue of AD patients is closely related to pathological progression. Secondly, Clusterin is involved in the deposition and formation of ß-amyloid, which is a crucial process in AD development. Furthermore, Clusterin may affect the pathogenesis of AD through mechanisms such as regulating inflammation, controlling cell apoptosis, and clearing pathological proteins. Therefore, further research on the relationship between Clusterin and AD will contribute to a deeper understanding of the etiology of this neurodegenerative disease and provide a theoretical basis for developing early diagnostic and therapeutic strategies for AD. This also makes Clusterin one of the research focuses as a potential biomarker for AD diagnosis and treatment monitoring.

The histone deacetylase inhibitor SAHA exerts a protective effect against myocardial ischemia/reperfusion injury by inhibiting sodium-calcium exchanger.

Calcium overload performs a crucial function in the pathogenesis of myocardial ischemia-reperfusion (I/R) damage, which contributes to mitochondrial impairment and apoptosis of cardiomyocytes. Suberoylanilide hydroxamic acid (SAHA), a small molecule histone deacetylases inhibitor with modulatory capacity on Na+-Ca2+ exchanger (NCX), is proven to have protective potential towards cardiac remodeling and injury, but the mechanism remains unclear. Hence, Hence, our present research explored the modulation of NCX-Ca2+-CaMKII by SAHA in myocardial I/R damage. Our outcomes indicate that in vitro hypoxia and reoxygenation models of myocardial cells, SAHA treatment inhibited the increase in expression of NCX1, intracellular Ca2+ concentration, expression of CaMKII and self-phosphorylated CaMKII, and cell apoptosis. In addition, SAHA treatment improved myocardial cell mitochondrial swelling inhibited mitochondrial membrane potential diminution and the openness of the mitochondrial permeability transition pore, and protected against mitochondrial dysfunction following I/R injury. In vivo, SAHA treatment alleviated the decrease in FS% and EF%, the increase in the myocardial infarct area, and myocardial enzyme levels caused by I/R injury, while also reducing myocardial cell apoptosis, and inhibiting mitochondrial fission and mitochondrial membrane rupture. These results indicated that SAHA treatment alleviated myocardial cell apoptosis as well as mitochondrial dysfunction resulting from myocardial I/R impairment, and contributed to myocardial function recovery by inhibiting the NCX-Ca2+-CaMKII pathway. These findings offered additional theoretical support to explore the mechanism of SAHA as a therapeutic agent in cardiac I/R damage and develop new treatment strategies.

Speckle-tracking echocardiography provides sensitive measurements of subtle early alterations associated with cardiac dysfunction in T2DM rats.

BACKGROUND: Diabetic cardiomyopathy results in cardiac structural and functional abnormalities. Previous studies have demonstrated that inhibiting the RhoA/ROCK signalling pathway increases the injury resistance of cardiomyocytes. The early detection of cardiac structural and functional alterations may facilitate an improved understanding of the pathophysiologic progress and guide therapy. This study aimed to identify the optimal diagnostic measures for the subtle early alterations of cardiac dysfunction in type 2 diabetes mellitus (T2DM) rats. METHODS: Twenty-four rat models were divided into four groups and received treatments for 4 weeks: the CON group (control rats), the DM group (T2DM rats), the DMF group (T2DM rats receiving fasudil) and the CONF group (control rats receiving fasudil) group. Left ventricular (LV) structure was quantified by histological staining and transmission electron microscopy. LV function and myocardial deformation were assessed by high-frequency echocardiography. RESULTS: Treatment with fasudil, a ROCK inhibitor, significantly protected against diabetes-induced myocardial hypertrophy, fibrosis and mitochondrial dysfunction. Impaired LV performance was found in T2DM rats, as evidenced by significant reductions in the ejection fraction (EF), fractional shortening (FS) and the mitral valve (MV) E/A ratio (which decreased 26%, 34% and 20%, respectively). Fasudil failed to improve the conventional ultrasonic parameters in T2DM rats, but the myocardial deformation measured by speckle-tracking echocardiography (STE) were significantly improved (global circumferential strain, GCS: P = 0.003; GCS rate, GCSR: P = 0.021). When receiver operating characteristic (ROC) curves were used in combination with linear regression analysis, STE parameters were found to be characterized by both optimal prediction of cardiac damage [AUC (95% CI): fractional area change, FAC: 0.927 (0.744, 0.993); GCS: 0.819 (0.610, 0.945); GCSR: 0.899 (0.707, 0.984)] and stronger correlations with cardiac fibrosis (FAC: r = -0.825; GCS: r = 0.772; GCSR: r = 0.829) than conventional parameters. CONCLUSION: The results suggest that STE parameters are more sensitive and specific than conventional parameters in predicting the subtle cardiac functional changes that occur in the early stage, providing new insight into the management of diabetic cardiomyopathy.

Compound Kushen injection attenuates angiotensin II­mediated heart failure by inhibiting the PI3K/Akt pathway.

Compound Kushen injection (CKI) is a type of traditional Chinese medicine that has previously been studied for the treatment of various types of cancer. Previous studies have reported that CKI regulates cell apoptosis by downregulating the PI3K/Akt pathway. The present study aimed to determine whether CKI alleviates heart failure (HF) by attenuating cardiomyocyte apoptosis via the inhibition of the PI3K/Akt pathway. Angiotensin II (Ang II) was used to elicit HF, and osmotic minipumps with either Ang II (2 µg/kg/day) or phosphate­buffered saline (PBS; 200 µl) were subcutaneously implanted into 6­week­old male C57BL/6 mice for 3 weeks. In addition, PBS or CKI (25 mg/kg/day) were subcutaneously infused once a day for 3 weeks. Echocardiography was used to examine hemodynamics. The myocardial injury biomarkers, cardiac troponin I and N­terminal (NT)­pro hormone B­type natriuretic peptide, were assessed using enzyme­linked immunosorbent assay. Transmission electron microscopy was used to determine the morphology of the myocardium. The rate of apoptosis was detected using TUNEL staining and flow cytometry (FCM), and the expression levels of apoptosis­related proteins were measured using western blot (WB) analysis. Moreover, H9C2 cells were treated with CKI (2 mg/ml) or LY294002 (an inhibitor of the PI3K/Akt pathway; 25 µmol/l) in combination with Ang II (1 µmol/l) for 48 h. Cell Counting Kit­8 assay, FCM and WB analysis were performed in the H9C2 cells to examine cell viability, cell cycle distribution and representative signaling proteins. It was found that CKI promoted healthy cardiac function, reduced myocardial structural damage and reduced the rate of cardiomyocyte apoptosis. CKI markedly attenuated the expression of apoptosis­related proteins in the PI3K/Akt pathway. The results of the in vitro experiments indicated that CKI promoted cardiomyocyte proliferation and inhibited apoptosis, similar to LY294002. On the whole, the present study demonstrates that CKI reduces cardiomyocyte apoptosis, promotes healthy cardiac function and attenuates Ang II­mediated HF. These ameliorative effects may be associated with the inhibition of the PI3K/Akt pathway.

Estimation of groundwater residence time with deeply-derived carbon mixture considered in California.

Groundwater has experienced long-term overdraft due to drought and human activities in California, resulting in issues of land subsidence and groundwater anthropogenic contamination. As a useful indicator of groundwater renewal rate and its residence time, groundwater age has been conventionally investigated based on 14C content and 3H concentration. However, the influence of deeply-derived (endogenic) CO2 mixture is not fully and quantitatively considered, although endogenic carbon contributes a large part of the dissolved inorganic carbon in groundwater. Combined with 3H concentration, both conventional and modified 14C-dating methods with endogenic CO2 mixture considered are employed for groundwater age determination in California. On average, the conventional groundwater 14C apparent age is overestimated by ~4.9 kyr or ~26.2 %, causing groundwater recharge rate underestimation and aquifer recovery time overestimation by ~46.0 % and ~26.2 %, respectively. High 3H concentration indicates modern water mixture in more than one fifth of groundwater samples, including those with high modified 14C apparent age (> 12 kyr, i.e., fossil groundwater) in the Central Valley and southern California, which are generally considered not to be recharged by modern water. Modern water mixture in old groundwater can potentially bring anthropogenic contamination to these groundwater resources, which should be paid attentions by the government and the managers. The results have important implications in evaluation of groundwater replenishment and its susceptibility to modern contamination in California, and in groundwater resources estimation globally.

Impact of various periods of perfusion-pause and reperfusion on the severity of myocardial injury in the langenodorff model.

BACKGROUND: To explore impact of various periods of ischemia and reperfusion on the severity of myocardial injury. METHODS: Langendorff model of isolated cardiac perfusion system was established in 56 rat hearts. They were randomly assigned into four groups with four different ischemia (perfusion-pause) time and reperfusion time. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and creatine kinase-MB (CK-MB) were measured and the size of myocardial infarction was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. RESULTS: The levels of AST, ALT, LDH, and CK-MB in the heart tissues and perfusate were lowest in the group I (shortest time of perfusion-pause and reperfusion) followed by the groups II, III, and IV (longest time of perfusion-pause and reperfusion) (p < 0.05). The myocardial infarction size was smallest in the group I (6.63 ± 0.47) followed by group II (15.12 ± 1.03), group III (20.32 ± 2.18), and group IV (32.29 ± 5.42) (p < 0.05). Two-way ANOVA analysis revealed that period of perfusion-pause and reperfusion independently and significantly affected the levels of AST and ALT in both heart tissues and perfusate (p < 0.001). The interaction of pausing period and reperfusion significantly affected the level of AST (p = 0.046) and CK-MB (p = 0.001) in the perfusate. In addition, perfusion-pause period significantly affected levels of LDH and CK-MB only in the perfusate (p < 0.001). Neither perfusate nor heart tissue LDH level was significantly affected by the interaction of perfusion-pause and reperfusion period (p > 0.05). CONCLUSION: The severity of myocardial injury in the Langendorff model was affected by the period of perfusion-pause and reperfusion. The longer period of perfusion-pause followed by the longer the period of reperfusion, the severe myocardial injury was found.

Effect of Nursing Intervention on Coronary CT Angiography in Elderly Patients.

To investigate the clinical benefits of coronary CT angiography in older adults. The results of this trial were 110 patients who underwent CT angiography (selected from 20 March 2016 to 20 March 2017). Use computer group mode. The control group received health care, including 50 patients, and the control group received usual care, including 60 patients. Then, the best and best image quality, time-consuming analysis, and satisfaction were compared between the two groups. The experimental results showed that the best and best image quality (83.00%), examination time (5.72 ± 1.81) minutes, and patient satisfaction (100.00%) of the experimental group were better than those of the control group (P < 0.05). Targeted healthcare for patients undergoing coronary CT angiography can improve the patient's ability to receive a diagnosis with a consistent attitude, reduce work hours, reduce adverse factors, and improve patient satisfaction with care.

Pharmacological activation of estrogenic receptor G protein-coupled receptor 30 attenuates angiotensin II-induced atrial fibrosis in ovariectomized mice by modulating TGF-ß1/smad pathway.

BACKGROUND: G-protein-coupled ER (GPR30) plays an important role in cardioprotection. Recent studies have shown that the GPR30-specific agonist G-1 reduces the degree of myocardial fibrosis in rats with myocardial infarction, reduces the morbidity associated with atrial fibrillation, and inhibits the proliferation of cardiac fibroblasts in animal experiments. Nevertheless, the underlying mechanism of myocardial fibrosis and atrial fibrillation remains unclear. In this study, we explored the mechanism underlying the effect of GPR30 on atrial fibrosis and atrial fibrillation in OVX mice. METHODS: We established an animal model of atrial fibrillation induced by Ang II (derived from OVX C57BL/6 female mice) and observed the role of G-1 in cardiac function by echocardiography, hemodynamics, morphology and fibrosis-related and apoptosis-related protein expression by Masson's trichrome, immunofluorescence, western blotting and TUNEL staining. RESULTS: Echocardiography and body surface ECG showed that G-1 combined with Ang II significantly reduced atrial fibrosis and atrial fibrillation compared to Ang II alone. The G-1 treatment group exhibited changes in the mRNA and protein expression of apoptosis-related genes. Moreover, G-1 treatment also altered the levels of inflammation-related proteins and mRNAs. In primary cultured cardiac fibroblasts (CFSs), proliferation was significantly increased in response to Ang II, and G-1 inhibited cell proliferation and apoptosis. CONCLUSION: GPR30 is a potential therapeutic target for alleviating atrial fibrosis in OVX mice by upregulating Smad7 expression to inhibit the TGF-ß/Smad pathway.

Metformin alleviates bevacizumab-induced vascular endothelial injury by up-regulating GDF15 and activating the PI3K/AKT/FOXO/PPARγ signaling pathway.

BACKGROUND: Previous studies have reported that the combination of metformin and bevacizumab exhibit favorable efficacy in the treatment of cancer patients, and metformin possesses effects on relieving vascular injury in multiple diseases. Nonetheless, the effect of metformin in alleviating bevacizumab-induced vascular injury remains unknown. Therefore, the present study aimed to investigate the impact of metformin on apoptosis, vascular endothelial injury marker expressions, and inflammation in human umbilical vein endothelial cells (HUVECs), as well as its possible molecular mechanism. METHODS: HUVECs were treated with bevacizumab, metformin or both, and subsequently treated with growth differentiation factor 15 (GDF15) overexpression plasmid, negative control (NC) plasmid, GDF15 small interfering ribonucleic acid (siRNA), NC siRNA, and the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, respectively. After treatment, apoptosis, levels of endothelial injury biomarkers and the potential downstream proteins were detected. RESULTS: Bevacizumab increased the levels of apoptosis, vascular endothelial injury marker expressions and pro-inflammatory cytokine expressions in HUVECs, while metformin alleviated these effects in bevacizumab-treated HUVECs. Furthermore, GDF15 overexpression reduced the apoptosis, vascular endothelial injury marker expressions, pro-inflammatory cytokine expressions, and activated the PI3K/protein kinase B (AKT)/forkhead box O (FOXO)/peroxisome proliferator-activated receptor γ (PPARγ) signaling pathway in bevacizumab-treated HUVECs. Subsequently, GDF15 siRNA reduced the effects of metformin on the bevacizumab-induced vascular endothelial injury (as described above) in HUEVCs. Lastly, the PI3K inhibitor exhibited similar effects to those of GDF15 siRNA in bevacizumab-treated HUVECs. CONCLUSIONS: Metformin protected against bevacizumab-induced vascular endothelial injury via activation of GDF15 and the PI3K/AKT/FOXO/PPARγ signaling pathway.

The Application Potential and Advance of Mesenchymal Stem Cell-Derived Exosomes in Myocardial Infarction.

Myocardial infarction (MI) is a devastating disease with high morbidity and mortality caused by the irreversible loss of functional cardiomyocytes and heart failure (HF) due to the restricted blood supply. Mesenchymal stem cells (MSCs) have been emerging as lead candidates to treat MI and subsequent HF mainly through secreting multitudinous factors of which exosomes act as the most effective constituent to boost the repair of heart function through carrying noncoding RNAs and proteins. Given the advantages of higher stability in the circulation, lower toxicity, and controllable transplantation dosage, exosomes have been described as a wonderful and promising cell-free treatment method in cardiovascular disease. Nowadays, MSC-derived exosomes have been proposed as a promising therapeutic approach to improve cardiac function and reverse heart remodeling. However, exosomes' lack of modification cannot result in desired therapeutic effect. Hence, optimized exosomes can be developed via various engineering methods such as pharmacological compound preconditioned MSCs, genetically modified MSCs, or miRNA-loaded exosomes and peptide tagged exosomes to improve the targeting and therapeutic effects of exosomes. The biological characteristics, therapeutic potential, and optimizing strategy of exosomes will be described in our review.

SM22α Loss Contributes to Apoptosis of Vascular Smooth Muscle Cells via Macrophage-Derived circRasGEF1B.

Vascular smooth muscle cell (VSMC) apoptosis is a major defining feature of abdominal aortic aneurysm (AAA) and mainly caused by inflammatory cell infiltration. Smooth muscle (SM) 22α prevents AAA formation through suppressing NF-κB activation. However, the role of SM22α in VSMC apoptosis is controversial. Here, we identified that SM22α loss contributed to apoptosis of VSMCs via activation of macrophages. Firstly, deficiency of SM22α enhanced the interaction of VSMCs with macrophages. Macrophages were retained and activated by Sm22α -/- VSMCs via upregulating VCAM-1 expression. The ratio of apoptosis was increased by 1.62-fold in VSMCs treated with the conditional media (CM) from activated RAW264.7 cells, compared to that of the control CM (P < 0.01), and apoptosis of Sm22α -/- VSMCs was higher than that of WT VSMCs (P < 0.001). Next, circRasGEF1B from activated macrophages was delivered into VSMCs promoting ZFP36 expression via stabilization of ZFP36 mRNA. Importantly, circRasGEF1B, as a scaffold, guided ZFP36 to preferentially bind to and decay Bcl-2 mRNA in a sequence-specific manner and triggered apoptosis of VSMCs, especially in Sm22α -/- VSMCs. These findings reveal a novel mechanism by which the circRasGEF1B-ZFP36 axis mediates macrophage-induced VSMC apoptosis via decay of Bcl-2 mRNA, whereas Sm22α -/- VSMCs have a higher sensitivity to apoptosis.

Smooth muscle 22α deficiency impairs oxytocin-induced uterine contractility in mice at full-term pregnancy.

Smooth muscle 22α (SM22α, namely Transgelin), as an actin-binding protein, regulates the contractility of vascular smooth muscle cells (VSMCs) by modulation of the stress fiber formation. However, little is known about the roles of SM22α in the regulation of uterine contraction during parturition. Here, we showed that contraction in response to oxytocin (OT) was significantly decreased in the uterine muscle strips from SM22α knockout (Sm22α-KO) mice, especially at full-term pregnancy, which may be resulted from impaired formation of stress fibers. Furthermore, serious mitochondrial damage such as the mitochondrial swelling, cristae disruption and even disappearance were observed in the myometrium of Sm22α-KO mice at full-term pregnancy, eventually resulting in the collapse of mitochondrial membrane potential and impairment in ATP synthesis. Our data indicate that SM22α is necessary to maintain uterine contractility at delivery in mice, and acts as a novel target for preventive or therapeutic manipulation of uterine atony during parturition.

Circ_0068655 Promotes Cardiomyocyte Apoptosis via miR-498/PAWR Axis.

BACKGROUND: The cardiomyocyte apoptosis is considered as one of major contributions to cardiac remodeling after myocardial infarction (MI). Numerous studies find that circular RNAs (circRNAs) play pivotal roles in a variety of biological functions. However, the role of circ_0068655 in MI and human induced pluripotent stem-derived cardiomyocytes (HCMs) remains unknown. METHODS: The expression of circ_0068655, miR-498, and PRKC apoptosis WT1 regulator (PAWR) in human MI heart tissues and hypoxia subjected HCMs was evaluated with qRT-PCR and Western blot. The effects of circ_0068655 on hypoxia-induced apoptotic death and cell migration in HCMs were evaluated with qRT-PCR, cell viability, cell death ELISA (POD), and Caspase-3 activity assay, and Trans-well assay, respectively. Furthermore, luciferase assay, qRT-PCR, biotin-labeled miRNA pulldown assay, and Western blot were employed in the functional studies. RESULTS: We found that the expression of circ_0068655 and PAWR was enhanced in MI patients and hypoxia subjected HCMs; by contrast, the expression of miR-498 decreased. Inhibited expression of circ_0068655 in HMCs counteracted hypoxia-induced apoptotic death and impaired cell migration, in sharp contrast to circ_0068655 knockdown. We identified that circ_0068655 sponged an endogenous miR-498 to sequester and inhibit its activity, leading to the increased PAWR expression. CONCLUSIONS: Our findings reveal that the expression of circ_0068655 can promote cardiomyocyte apoptosis through the modulation of miR-498-PAWR axis in vitro, which highlights the diagnostic and therapeutic value of circ_0068655 in patients with MI.

Increased miR-34c mediates synaptic deficits by targeting synaptotagmin 1 through ROS-JNK-p53 pathway in Alzheimer's Disease.

Alzheimer's disease (AD) and cancer have inverse relationship in many aspects. Some tumor suppressors, including miR-34c, are decreased in cancer but increased in AD. The upstream regulatory pathways and the downstream mechanisms of miR-34c in AD remain to be investigated. The expression of miR-34c was detected by RT-qPCR in oxidative stressed neurons, hippocampus of SAMP8 mice, or serum of patients with amnestic mild cognitive impairment (aMCI). Dual luciferase assay was performed to confirm the binding sites of miR-34c in its target mRNA. The Morris water maze (MWM) was used to evaluate learning and memory in SAMP8 mice administrated with miR-34c antagomir (AM34c). Golgi staining was used to evaluate the synaptic function and structure. The dramatically increased miR-34c was mediated by ROS-JNK-p53 pathway and negatively regulated synaptotagmin 1 (SYT1) expression by targeting the 3'-untranslated region (3'-UTR) of syt1 in AD. The expression of SYT1 protein was reduced by over expression of miR-34c in the HT-22 cells and vice versa. Administration of AM34c by the third ventricle injection or intranasal delivery markedly increased the brain levels of SYT1 and ameliorated the cognitive function in SAMP8 mice. The serum miR-34c was significantly increased in patients with aMCI and might be a predictive biomarker for diagnosis of aMCI. These results indicated that increased miR-34c mediated synaptic and memory deficits by targeting SYT1 through ROS-JNK-p53 pathway and the miR-34c/SYT1 pathway could be considered as a promising novel therapeutic target for patients with AD.

Accumulation of Smooth Muscle 22α Protein Accelerates Senescence of Vascular Smooth Muscle Cells via Stabilization of p53 In Vitro and In Vivo.

OBJECTIVE: Smooth muscle (SM) 22α, an actin-binding protein, displays an upregulated expression as a marker during cellular senescence. However, the causal relationship between SM22α and senescence is poorly understood. This study aimed to investigate the role of SM22α in angiotensin II (Ang II)-induced senescence of vascular smooth muscle cells (VSMCs). APPROACH AND RESULTS: We prepared a model of VSMC senescence induced by Ang II and found that the expression of SM22α in VSMCs was increased in response to chronic Ang II treatment. Overexpression of SM22α promoted Ang II-induced VSMC senescence, whereas knockdown of SM22α suppressed this process. Moreover, this effect of SM22α was p53 dependent. Increased SM22α protein obstructed ubiquitination and degradation of p53 and subsequently improved its stability. Furthermore, SM22α inhibited phosphorylation of Mdm2 (mouse double minute 2 homolog), an E3 ubiquitin-protein ligase, accompanied by a decreased interaction between Mdm2 and p53. Using LY294002, a PI3K/Akt inhibitor, we found that PI3K/Akt-mediated Mdm2 phosphorylation and activation was inhibited in senescent or SM22α-overexpressed VSMCs, in parallel with decreased p53 ubiquitination. We further found that SM22α inhibited activation of PI3K/Akt/Mdm2 pathway via strengthening actin cytoskeleton. In the in vivo study, we showed that the disruption of SM22α reduced the increase of blood pressure induced by Ang II, associated with decreased VSMC senescence through a mechanism similar to that in VSMCs in vitro. CONCLUSIONS: In conclusion, these findings suggest that the accumulation of SM22α promotes Ang II-induced senescence via the suppression of Mdm2-mediated ubiquitination and degradation of p53 in VSMCs in vitro and in vivo.

CKII-SIRT1-SM22α loop evokes a self-limited inflammatory response in vascular smooth muscle cells.

AIMS: Sirtuin 1 (SIRT1) inhibits nuclear factor kappa B (NF-κB) activity in response to the inflammatory cytokine tumour necrosis factor alpha (TNF-α). Smooth muscle (SM) 22α is a phosphorylation-regulated suppressor of IKK-IκBα-NF-κB signalling cascades in vascular smooth muscle cells (VSMCs). Sm22α knockout results in increased expression of pro-inflammatory genes in the aortas which are controlled by NF-κB. This study aimed to investigate the relationship between SM22α and SIRT1 in the control of vascular inflammation. METHODS AND RESULTS: The ligation injury model of Sirt1-Tg/Sm22α-/- mice displayed an increased level of the inflammatory molecules in the carotid arteries compared with Sirt1-Tg mice, accompanied with aggravating neointimal hyperplasia. In the in vitro study, on the one hand, we showed that TNF-α induced the epigenetic silencing of SM22α transcription via EZH2-mediated H3K27 methylation in the SM22α promoter region, contributing to inflammatory response. On the other hand, TNF-α simultaneously induced SIRT1 phosphorylation via CKII and thereby protected against inflammation. Phosphorylated SIRT1 interacted with and deacetylated EZH2 and, subsequently, promoted SM22α transcription by inhibiting EZH2 activity. Increased SM22α in turn facilitated the phosphorylation and activation of SIRT1 via recruitment of CKII to SIRT1, which amplified the anti-inflammatory effect of SIRT1. CONCLUSION: Our findings demonstrate that, in response to TNF-α stimulation, CKII-SIRT1-SM22α acts in a loop to reinforce the expression of SM22α, which limits the inflammatory response in VSMCs in vivo and in vitro. The anti-inflammatory effect of SIRT1 may be dependent on SM22α to some extent. Our data point to targeted activation of SIRT1 in VSMCs as a promising therapeutic avenue in preventing cardiovascular diseases.