Macrophage RAGE deficiency prevents myocardial fibrosis by repressing autophagy-mediated macrophage alternative activation.

Myocardial fibrosis (MF) is the characteristic pathological feature of various cardiovascular diseases that lead to heart failure (HF) or even fatal outcomes. Alternatively, activated macrophages are involved in the development of fibrosis and tissue remodeling. Although the receptor for advanced glycation end products (RAGE) is involved in MF, its potential role in regulating macrophage function in cardiac fibrosis has not been fully investigated. We aimed to determine the role of macrophage RAGE in transverse aortic constriction (TAC)-induced MF. In this study, we found that RAGE expression was markedly increased in the infiltrated alternatively activated macrophages within mice hearts after TAC. RAGE knockout mice showed less infiltration of alternatively activated macrophages and attenuated cardiac hypertrophy and fibrosis compared to the wild-type mice. Our data suggest that mice with macrophage-specific genetic deletion of RAGE were protected from interstitial fibrosis and cardiac dysfunction when subjected to pressure overload, which led to a decreased proportion of alternatively activated macrophages in heart tissues. Our in vitro experiments demonstrated that RAGE deficiency inhibited the differentiation into alternatively activated macrophages by suppressing autophagy activation. In the co-culture system, in vitro polarization of RAW264.7 macrophages toward an alternatively activated phenotype stimulated the expression of α-smooth muscle actin and collagen in cardiac fibroblasts. However, the knockdown of RAGE and inhibition of autophagy in macrophages showed reduced fibroblast-to-myofibroblast transition (FMT). Collectively, our results suggest that RAGE plays an important role in the recruitment and activation of alternatively activated macrophages by regulating autophagy, which contributes to MF. Thus, blockage of RAGE signaling may be an attractive therapeutic target for the treatment of hypertensive heart disease.

Inhibition of AGEs-RAGE-PP2A Axis Alleviates Cognitive Impairment after Chronic Heart Failure.

To investigate the effect of the AGEs-RAGE-PP2A axis on cognitive impairment (CI) after chronic heart failure (CHF). Mice were divided into six groups: Sham, TAC, Sham+RAGE-/-, TAC+RAGE-/-, AG, and FTY720 group. AG mice and FTY720 mice were treated with AGEs inhibitor (aminoguanidine, AG) and PP2A activator (FTY720) respectively after TAC surgery. The cardiac function of AG and TAC+RAGE-/- mice was significantly better than that of TAC mice (P<0.05). However, the heart function of FTY720 mice were just improved a part of that. To behavioral function, the escape latency period of the TAC+RAGE-/-, AG and FTY720 mice were significantly shorter (P<0.05), and the times of platform crossings and residence time of them were significantly improved (P<0.05). HE staining and silver staining show the structure of TAC+RAGE-/-, AG and FTY720 mice were more complete. Also, in these three groups, the expression of Aß and p-tau protein in the brain can be significantly down-regulated (P<0.05) and the PP2A protein expression level was up-regulated (P<0.05). And the expression of hippocampal Bax, Cyt-C, and Caspase-3 of that were all down-regulated (P<0.05), and Bcl-2 was up-regulated (P<0.05). Deficient of AGEs, RAGE and activating PP2A can significantly attenuate the cognitive impairment in CHF mice, and protect the brain structure. This mechanism seems via reducing the expression of Aß, p-tau, and apoptotic protein.

Plantamajoside attenuates cardiac fibrosis via inhibiting AGEs activated-RAGE/autophagy/EndMT pathway.

Advanced glycation end products (AGEs) have been identified to transduce fibrogenic signals via inducing the activation of their receptor (RAGE)-mediated pathway. Recently, disrupting AGE-RAGE interaction has become a promising therapeutic strategy for chronic heart failure (CHF). Endothelial-to-mesenchymal transition (EndMT) is close to the cardiac fibrosis pathological process. Our previous studies have demonstrated that knockout RAGE suppressed the autophagy-mediated EndMT, and thus alleviated cardiac fibrosis. Plantamajoside (PMS) is the major bioactive compound of Plantago Asiatica, and its activity of anti-fibrosis has been documented in many reports. However, its effect on CHF and the underlying mechanism remains elusive. Thus, we tried to elucidate the protective role of PMS in CHF from the viewpoint of the AGEs/RAGE/autophagy/EndMT axis. Herein, PMS was found to attenuate cardiac fibrosis and dysfunction, suppress EndMT, reduce autophagy levels and serum levels of AGEs, yet did not affect the expression of RAGE in CHF mice. Mechanically, PMS possibly binds to the V-domain of RAGE, which is similar to the interaction between AGEs and RAGE. Importantly, this competitive binding disturbed AGEs-induced the RAGE-autophagy-EndMT pathway in vitro. Collectively, our results indicated that PMS might exert an anti-cardiac fibrosis effect by specifically binding RAGE to suppress the AGEs-activated RAGE/autophagy/EndMT pathway.

AGEs-RAGE axis mediates myocardial fibrosis via activation of cardiac fibroblasts induced by autophagy in heart failure.

NEW FINDINGS: What is the central question of this study? Does the advanced glycation end products (AGEs)-receptor for advanced glycation end products (RAGE) axis mediate myocardial fibrosis in heart failure? What is the main finding and its importance? The AGEs-RAGE axis is involved in the pathogenesis of myocardial fibrosis through activation of cardiac fibroblasts induced by autophagy in heart failure. By suppression of cardiac fibroblast activation, inhibition of the AGEs-RAGE axis attenuates cardiac dysfunction and myocardial fibrosis in mice with transverse aortic constriction. ABSTRACT: Heart failure is the end stage of cardiovascular disease and is a critical medical condition that poses an important therapeutic challenge for physicians owing to its high morbidity and mortality. Myocardial fibrosis is part of the remodelling process that occurs in heart failure. Many studies have shown that advanced glycation end products (AGEs) and receptor for advanced glycation end products (RAGE) are implicated in fibrosis and autophagy, but the mechanism remains unclear. In this study, we elucidated the mechanism by which the AGEs-RAGE axis mediates activation of cardiac fibroblasts (CFs) in heart failure. We used C57BL/6J wild-type (WT) mice to establish a model of heart failure by transverse aortic constriction (TAC). After 6 weeks of treatment, relevant indicators were detected. In mice subjected to TAC, AGEs were upregulated compared with sham-operated mice. Inhibition of RAGE resulted in functional cardiac protection, with reduced hypertrophy and fibrosis in mice after TAC. Of note, autophagy mediated the activation of CFs that transformed to myofibroblasts and contributed to fibrosis. In vitro, CFs were obtained from neonatal Sprague-Dawley rats and treated with AGEs, bovine serum albumin and short hairpin RNA (shRNA) for RAGE, in order to verify the results obtained in vivo. These results suggest that the AGEs-RAGE axis is involved in the pathogenesis of myocardial fibrosis in heart failure through CF activation induced by autophagy. Inhibition of the AGEs-RAGE axis attenuates cardiac dysfunction and myocardial fibrosis in mice with TAC by suppressing CF activation.

CT-guided minimally-invasive penile fracture repair.

We present the case of a 28 year old patient with an incomplete tear of the tunica albuginea occurred after having sexual intercourse in the female superior position. The diagnostic assessment was performed first clinically, then with CT, owing to its high resolution, allowed to exactly detect the tear location leading to precise preoperative planning. After adequate diagnosis through imaging and proper planning, the patient was performed a selective minimally invasive surgical approach to repair the lesion. The patient had good erection with no angular deformity or plaque formation after a 3-month follow-up.

Positive feedback regulation of stgR expression for secondary metabolism in Streptomyces coelicolor.

LysR-type transcriptional regulators (LTTRs) compose a large family and are responsible for various physiological functions in bacteria, while little is understood about their regulatory mechanism on secondary metabolism in Streptomyces. Here we reported that StgR, a typical LTTR in Streptomyces coelicolor, was a negative regulator of undecylprodigiosin (Red) and γ-actinorhodin (Act) production in the early developmental phase of secondary metabolism by suppressing the expression of two pathway-specific regulator genes, redD and actII-orf4, respectively. Meanwhile, stgR expression was downregulated during secondary metabolism to remove its repressive effects on antibiotic production. Moreover, stgR expression was positively autoregulated by direct binding of StgR to its own promoter (stgRp), and the binding site adjacent to translation start codon was determined by a DNase I footprinting assay. Furthermore, the StgR-stgRp interaction could be destroyed by the antibiotic γ-actinorhodin produced from S. coelicolor. Thus, our results suggested a positive feedback regulatory mechanism of stgR expression and antibiotic production for the rapid and irreversible development of secondary metabolism in Streptomyces.

Knockout RAGE alleviates cardiac fibrosis through repressing endothelial-to-mesenchymal transition (EndMT) mediated by autophagy.

Endothelial-to-mesenchymal transition (EndMT) has been shown to contribute to cardiac fibrosis and heart failure (HF). Recent studies have demonstrated that EndMT is regulated by autophagy, and we previously showed suppression of excessive autophagy and alleviation of cardiac fibrosis in HF mice with inactivated receptor for advanced glycation end products (RAGE). Thus, we investigated whether reduced cardiac fibrosis due to RAGE knockout occurred by inhibiting EndMT mediated by excessive autophagy. We found a decrease in endothelial cells (CD31+/VE-Cadherin+) and an increase in cells co-expressing CD31 and α-smooth muscle actin (α-SMA, myofibroblast marker) at 8 weeks in heart tissue of mice subjected to transverse aortic constriction (TAC), which implied EndMT. Knockout RAGE decreased EndMT accompanied by decreased expression of autophagy-related proteins (LC3BII/I and Beclin 1), and alleviated cardiac fibrosis and improved cardiac function in TAC mice. Moreover, 3-methyladenine (3-MA) and chloroquine (CQ), inhibitors of autophagy, attenuated EndMT, and cardiac fibrosis in TAC mice. Importantly, EndMT induced by AGEs could be blocked by autophagy inhibitor in vivo and in vitro. These results suggested that AGEs/RAGE-autophagy-EndMT axis involved in the development of cardiac fibrosis and knockout RAGE ameliorated cardiac fibrosis through decreasing EndMT regulated by autophagy, which could be a promising therapeutic strategy for HF.

Pyroptosis and ferroptosis induced by mixed lineage kinase 3 (MLK3) signaling in cardiomyocytes are essential for myocardial fibrosis in response to pressure overload.

Chronic heart failure (CHF) is the final outcome of many cardiovascular diseases, and is a severe health issue faced by the elderly population. Mixed lineage kinase 3 (MLK3), a member of MAP3K family, is associated with aging, inflammation, oxidative stress, and related diseases, such as CHF. MLK3 has also been reported to play an important role in protecting against cardiomyocyte injury; however, its function in myocardial fibrosis is unknown. To investigate the role of MLK3 in myocardial fibrosis, we inhibited the expression of MLK3, and examined cardiac function and remodeling in TAC mice. In addition, we assessed the expression of MLK3 protein in ventricular cells and its downstream associated protein. We found that MLK3 mainly regulates NF-κB/NLRP3 signaling pathway-mediated inflammation and that pyroptosis causes myocardial fibrosis in the early stages of CHF. Similarly, MLK3 mainly regulates the JNK/p53 signaling pathway-mediated oxidative stress and that ferroptosis causes myocardial fibrosis in the advanced stages of CHF. We also found that promoting the expression of miR-351 can inhibit the expression of MLK3, and significantly improve cardiac function in mice subjected to TAC. These results suggest the pyroptosis and ferroptosis induced by MLK3 signaling in cardiomyocytes are essential for adverse myocardial fibrosis, in response to pressure overload. Furthermore, miR-351, which has a protective effect on ventricular remodeling in heart failure caused by pressure overload, may be a key target for the regulation of MLK3.

Inhibiting Receptor of Advanced Glycation End Products Attenuates Pressure Overload-Induced Cardiac Dysfunction by Preventing Excessive Autophagy.

The receptor for advanced glycation end products (RAGE) is involved in heart failure (HF) by mediating diverse pathologic processes, including the promotion of inflammation and autophagy. However, the role of RAGE in pressure overload-induced HF is not well understood. We found that stimulation of RAGE triggered the death of neonatal rat ventricular myocytes (NRVMs), while cell death was alleviated by ATG5 knockdown. Using transverse aortic constriction (TAC) in mice as a model of pressure overload-induced HF, we demonstrated that RAGE knockout or RAGE blockade attenuated cardiac hypertrophy and fibrosis as well as cardiac dysfunction at 8 weeks after TAC. Importantly, RAGE knockout reversed upregulation of autophagy related proteins (LC3BII/I and Beclin 1) and reduced cardiomyocyte death, indicating that excessive autophagy after TAC was inhibited. Moreover, RAGE knockout or blockade reduced the upregulation of pp65-NFκB and BNIP3, which mediate autophagy. Taken together, these results suggest that RAGE plays an important role in the progression of HF by regulating autophagy. Therefore, inhibition of the RAGE-autophagy axis could be a promising new strategy for treatment of heart failure.

Folic acid reverses uric acid crystal-induced surface OAT1 internalization by inhibiting RhoA activity in uric acid nephropathy.

To investigate how organic anion transporter (OAT)-1 is involved in uric acid nephropathy (UAN), a rat model for UAN was established and the serum uric acid, blood urea nitrogen and serum creatinine levels were all measured, and observed to be increased. It was additionally identified that in UAN rats the surface OAT1 expression levels were reduced. By treating HEK cells with monosodium urate (MSU) crystals, it was observed that the cells exhibited a reduction in OAT1 levels. Furthermore, MSU crystals were observed to recruit Ras homolog family member A (RhoA), a small guanosine triphosphatase, to the membrane and activate it. Following RhoA activation, the OAT1 internalization rate was identified to be increased. The dominant­negative RhoA N19 mutation was able to block MSU­induced OAT1 internalization, indicating that the process was RhoA­dependent. Finally, the results indicated that folic acid, a daily nutritional supplement, was capable of rescuing MSU­induced nephropathy and OAT1 internalization. These observations indicated that uric acid crystals were able to reduce the OAT1 membrane distribution through activating RhoA, and that folic acid was capable of preventing MSU-induced OAT1 relocation by inhibiting the RhoA signaling pathway.

Organic Anion Transporter 1 Deficiency Accelerates Learning and Memory Impairment in tg2576 Mice by Damaging Dendritic Spine Morphology and Activity.

To investigate whether and how organic anion transporter 1 (OAT1) is involved in the process of Alzheimer's disease (AD), we crossbred OAT1 knockout mice with tg2576, the widely used AD model mice. Results here showed the heterozygous OAT1-deficient tg2576 mice developed a learning- and memory-related behavior deficiency and higher soluble Abeta amount in early stage (3 months old). Furthermore, the heterozygous mice brain slice also showed impaired long-term potentiation (LTP) and spontaneous excitatory postsynaptic currents (sEPSC). By crossbreeding heterozygous OAT1-deficient tg2576 mice with Thy-1 YFP mice, we got autofluoresced (layer 4/5 cortical neuron) heterozygous mice. By using two-photon microscope in the direct observation of mice brain in vivo or single photon confocal on slices, compared with control tg2576 mice, we found that the OAT1-deficient mice showed a higher spine numbers but with a much lesser maturity extent. Finally, by using glutamate uncaging method, we induced chemical LTP in brain slices and found that OAT1-deficient mice showed abnormal chemical-induced LTP, which meant that the deficient behavior may be caused by abnormal spine morphology and activity. Our results indicated OAT1 may be involved in AD process by regulating spine morphology and activity.

CT-guided minimally-invasive penile fracture repair

ABSTRACT We present the case of a 28 year old patient with an incomplete tear of the tunica albuginea occurred after having sexual intercourse in the female superior position. The diagnostic assessment was performed first clinically, then with CT, owing to its high resolution, allowed to exactly detect the tear location leading to precise preoperative planning. After adequate diagnosis through imaging and proper planning, the patient was performed a selective minimally invasive surgical approach to repair the lesion. The patient had good erection with no angular deformity or plaque formation after a 3-month follow-up.