Effects of mTOR/NF‐κB signaling pathway and high thoracic epidural anesthesia on myocardial ischemia‐reperfusion injury via autophagy in rats

Autophagy in adipogenesis: Molecular mechanisms and regulation by bioactive compounds

White adipose tissue expands rapidly due to increased adipocyte number (hyperplasia) and size (hypertrophy), which results in obesity. Adipogenesis is a process of the formation of mature adipocytes from precursor cells. Additionally, obesity-related metabolic complications, such as fatty liver and insulin resistance, are linked to adipogenesis. On the contrary, autophagy is a catabolic process; essential to maintain cellular homeostasis via the degradation or recycling of unnecessary or damaged components. Importantly, autophagy dictates obesity and adipogenesis. Hence, a clear understanding of how autophagy regulates adipogenesis is crucial for drug development and the prevention and treatment of obesity and its associated disorders, such as type 2 diabetes, cardiovascular disease, and cancer. In this review, we highlighted recent findings regarding the crosstalk between adipogenesis and autophagy, as well as the molecules involved. Furthermore, the review discussed how bioactive compounds regulate adipogenesis by manipulating autophagy and underlying molecular mechanisms. Based on in vitro and animal studies, we summarized the effects of bioactive compounds on adipogenesis and autophagy. Hence, human studies are necessary to validate the effectiveness and optimal dosage of these bioactive compounds.

Inhibition of HMGB1 alleviates myocardial ischemia/reperfusion injury in diabetic mice via suppressing autophagy

BACKGROUND

Diabetes aggravates myocardial ischemia/reperfusion (I/R) injury (MI/RI). The association between high mobility group box 1 protein (HMGB1) and autophagy in diabetic MI/RI remains unknown. Therefore, we investigated whether inhibiting HMGB1 can regulate autophagy in diabetic mice (DM) after I/R injury.

METHODS

I/R models of C57BL/KsJ mice and db/db mice were established. Histological changes, infarct size (IS), HMGB1 protein, and autophagy-related proteins were detected after 24h of reperfusion. In DM treatment groups, anti-HMGB1 antibody (H-Ig) was injected via tail vein after reperfusion for 15min, and the above-mentioned experimental methods were performed at the end of reperfusion.

RESULTS

Compared with the I/R group, the pathological myocardial damage and IS were significantly increased in the I/R (DM) group. Additionally, the levels of HMGB1, Beclin1, and LC3II/LC3I ratio were remarkably higher in the I/R (DM) group than those in the I/R group, while p62 level was lower. In the H-Ig (DM) group, injection of H-Ig significantly reduced the IS, as well as alleviated pathological myocardial damage. Moreover, Beclin1, LC3II/LC3I ratio, and p62 levels were notably reversed after this treatment.

CONCLUSIONS

I/R-induced myocardium was aggravated by diabetes, which may be related to increased release of HMGB1 and activated autophagy. Inhibition of HMGB1 alleviates diabetic MIRI which was associated with reduced autophagy.

S100A1 is Involved in Myocardial Injury Induced by Exhaustive Exercise

Many studies have confirmed that exhaustive exercise has adverse effects on the heart by generating reactive oxygen species (ROS). S100A1 calcium-binding protein A1 (S100A1) is a regulator of myocardial contractility and a protector against myocardial injury. However, few studies have investigated the role of S100A1 in the regulation of myocardial injury induced by exhaustive exercise. In the present study, we suggested that exhaustive exercise led to increased ROS, downregulation of S100a1, and myocardial injury. Downregulation of S100a1 promoted exhaustive exercise-induced myocardial injury and overexpression of S100A1 reversed oxidative stress-induced cardiomyocyte injury, indicating S100A1 is a protective factor against myocardial injury caused by exhaustive exercise. We also found that downregulation of S100A1 promoted damage to critical proteins of the mitochondria by inhibiting the expression of Ant1, Pgc1a, and Tfam under exhaustive exercise. Our study indicated S100A1 as a potential prognostic biomarker or therapeutic target to improve the myocardial damage induced by exhaustive exercise and provided new insights into the molecular mechanisms underlying the myocardial injury effect of exhaustive exercise.

Uhrf1 regulates H3K9me2 modification of mTOR to inhibit the effect of autophagy in myocardial ischemia-reperfusion injury

The regulation of mTOR and the dimethylation of histone H3 on lysine 9 (H3K9me2) H3K9me2 by Uhrf1 and the mechanism of autophagy regulation in myocardial ischemia-reperfusion injury (MIRI) were studied in vivo and in vitro.

An in vitro I/R injury model was established using the primary mouse cardiomyocytes treated with H₂O₂. Subsequent analysis by qRT-PCR, western blot, and immunofluorescence indicated that overexpression of Uhrf1 significantly inhibited apoptosis of the H₂O₂-treated cardiomyocytes, reduced expression of apoptosis factors caspase-3 and Bax, and increased expression of apoptosis inhibitory factor Bcl-2. Furthermore, Uhrf1 was found to increase cardiomyocyte proliferation and promote the expression of mTOR, while the four expression peaks of H3K9me2 on the mTOR gene were inhibited by overexpression of Uhrf1. The expression of autophagy factors LC3, Beclin-1, and p-mTOR in Uhrf1-overexpressed cardiomyocytes was dramatically increased, and P62 expression was dramatically decreased. When an H3K9me2 inhibitor was added to the Uhrf1-knockdown cardiomyocytes, the expression of mTOR was increased, the expression of LC3, Beclin-1, and p-mTOR was decreased, and P62 expression was significantly increased.

In the present study, Uhrf1 exhibits a protective function in MIRI, reducing the apoptosis of cardiomyocytes while increasing their proliferation and viability.

Ischemic postconditioning reduced myocardial ischemia-reperfusion injury: The roles of melatonin and uncoupling protein 3

Objective:

Protective effects of ischemic postconditioning (PostC) decrease/disappear with age and chronic heart diseases. Similarly, low serum melatonin levels have been reported in the same risk groups. The aims of this study were to investigate the effects of melatonin on the protection of PostC in ischemia–reperfusion (I/R)-induced infarct size and roles of uncoupling protein (UCP) 3, irisin, and nuclear factor kappa B (NFkB) levels.

Methods:

Rats were pinealectomized (Px) or sham operated (non-Px) 2 months before the I/R studies. The left main coronary artery was occluded for 30 min followed by 120 min reperfusion. PostC was induced with three cycles of R/I (10 s each) after ischemia.

Results:

The infarct size was found to be significantly higher in Px rats (54.68±1.5%) than in the control group (35.1±2.5%). PostC and melatonin administrations to non-Px rats significantly reduced the infarct size. On the other hand, PostC did not create a significant effect in Px rats, but protection was provided when PostC was co-administrated with melatonin. While significant decreases were detected in the UCP3 levels, irisin and NFkB levels increased with I/R and Px. Treatment with PostC and melatonin in non-Px groups and their co-administration in Px groups were found to return all the genes close to normal levels.

Conclusion:

The physiological and pharmacological concentrations of melatonin may play a role in the protection of PostC. In cases when physiological melatonin is reduced, such as aging and heart diseases, this protection may decrease, and this effect may be restored by melatonin replacement. PostC and melatonin may regulate energy metabolism and inflammatory mediators and protect mitochondria by affecting the UCP3, irisin, and NFkB levels.

Hydroxysafflor Yellow A Protects Against Myocardial Ischemia/Reperfusion Injury via Suppressing NLRP3 Inflammasome and Activating Autophagy

Myocardial ischemia/reperfusion (MI/R) injury is a serious threat to human health. Hydroxysafflor yellow A (HSYA), the main water-soluble ingredient extracted from Carthami flos (Carthamus tinctorius L.), has therapeutic potential for treating MI/R injury. However, the mechanisms of HSYA−mediated protection from MI/R injury are incompletely understood. In the present study, we investigated the effects and the underlying mechanisms of HSYA during MI/R. Adult Sprague-Dawley rats were subjected to left anterior descending artery ligation for 30 min followed by 24 h of reperfusion with or without HSYA treatment. The protective effect of HSYA was detected by 2,3,5-triphenyl tetrazolium chloride (TTC) staining, hematoxylin eosin (HE) staining, and myocardial enzymes detections. Serum levels of inflammatory factors such as TNF-α, interleukin (IL)-1β, and IL-18, were detected using ELISA kits. The expression of NLRP3 and other related proteins in the myocardium was detected by western blot and immunohistochemistry. The expression of autophagy-related proteins, including Atg5, BECN1, P62, and LC3B, was detected by western blot to evaluate the effect of HSYA on autophagy. Results showed that HSYA decreased the myocardial infarct size and attenuated the cardiac dysfunction in rats after I/R. In addition, HSYA inhibited myocardial apoptosis compared with the I/R group, decreased the levels of inflammatory cytokines in rat serum, reduced NLRP3 inflammasome expression, and induced autophagy. Mechanistically, our results demonstrated that HSYA can activate AMPK to improve autophagy and inhibit NLRP3 inflammasome by inhibiting the mTOR pathway. This work provides strong data supporting for the clinical applications of HSYA in MI/R injury.

Oridonin Attenuates Myocardial Ischemia/Reperfusion Injury via Downregulating Oxidative Stress and NLRP3 Inflammasome Pathway in Mice

Oridonin (ORI), the major pharmacological component extracted from a traditional Chinese medicine, possesses a beneficial effect on myocardial ischemia/reperfusion (I/R) injury. However, the underlying molecular mechanism by which ORI effects take place is not completely known. Thus, whether ORI works via downregulating oxidative stress and nod-like receptor protein-3 (NLRP3) inflammasome pathway was investigated in this study. Mice underwent surgery to induce myocardial I/R injury, and some were administered ORI (10 mg/kg/day) pretreatment, while others were not. The myocardial enzymes' levels, infarct area, and inflammatory injury were measured. The activation situation of oxidative stress and NLRP3 inflammasome was also detected. We found that ORI pretreatment significantly alleviated CK-MB and cTnI levels and infarct size induced by I/R. ORI mitigated the inflammatory injury by decreasing the pathological damage and lowering TNF-α, IL-1β, and IL-18 levels. Moreover, the SOD1 and eNOS levels were significantly increased by ORI, while MDA and iNOS levels were relatively decreased. The oxidative stress was reversed using ORI pretreatment. Importantly, NLRP3 inflammasome pathway was also inhibited by ORI, as reflected by the lower protein levels of NLRP3, caspase-1, and IL-1β. In conclusion, ORI alleviates myocardial injury induced by I/R via inhibiting the oxidative stress and NLRP3 inflammasome pathway.

α7nAChR Deletion Aggravates Myocardial Infarction and Enhances Systemic Inflammatory Reaction via mTOR-Signaling-Related Autophagy

Alpha7 nicotinic acetylcholine receptor (α7nAChR) has been previously reported to play an alleviative role in myocardial infarction (MI). In this study, we investigated its specific mechanism. α7nAChR^-/- mice and its control (α7nAChR^+/+) were used for the study of α7nAChR. Left anterior descending coronary artery occlusion was conducted for the creation of mice MI model and lipopolysaccharide (LPS) was used as inflammatory stressor in murine peritoneal macrophages. Triphenyltetrazolium chloride (TTC) staining and echocardiography was used for the detection of infarct size and cardiac function, respectively. Western blot was conducted for the testing of autophagy-related proteins and enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (RT-PCR) was used for the testing of proinflammatory cytokines. Rapamycin was used for the induction of autophagy through inhibiting mammalian target of rapamycin (mTOR)-related signaling. We found that knocking out α7nAChR enhanced the cardiac infarct size and damaged cardiac function in MI. α7nAChR deficiency increased the levels of several proinflammatory cytokines in serum and spleen from MI mice as well as murine macrophages under inflammatory stress. α7nAChR deletion decreased the level of autophagy in spleen from MI mice and macrophages under inflammatory stress. Rapamycin alleviated the cardiac function and systemic inflammatory reaction in MI mice as well as inflammatory reaction in macrophages under inflammatory stress, which was attenuated by knocking out α7nAChR. Our current study investigated the mechanism of α7nAChR-mediated cardio-protective and anti-inflammatory effect related to mTOR-related autophagy, which might provide a novel insight in the treatment of MI.

p27kip1 haploinsufficiency preserves myocardial function in the early stages of myocardial infarction via Atg5‑mediated autophagy flux restoration

Myocardial infarction (MI) is a leading cause of mortality in adults worldwide. Over the last two decades, gene therapy has been a hot topic in cardiology, and there has been a focus on cell cycle inhibitors and their protective effects on the myocardium post-MI. In our previous study, the haploinsufficiency of p27^kip1 (p27) was demonstrated to improve cardiac function in mice post-MI by promoting angiogenesis and myocardium protection through the secretion of growth factors. Autophagy is an adaptive response of cells to environmental changes, such as nutrient deprivation, ischemia and hypoxia. The appropriate regulation of autophagy may improve myocardial function by preventing apoptosis of cardiomyocytes. In this study, we used immunoassays, transmission electron microscopy and cardiac ultrasound to confirm that p27 haploinsufficiency prevents myocardial apoptosis by restoring autophagy protein 5-mediated autophagy flux in the early stages of MI. The present study provides a novel method for studying MI or ischemic heart disease therapy.

Physiological and pharmacological effects of melatonin on remote ischemic perconditioning after myocardial ischemia-reperfusion injury in rats: Role of Cybb, Fas, NfκB, Irisin signaling pathway

It has been found that remote organ/limb temporary ischemia, known as remote ischemic conditioning, can provide protection against the formation of lethal ischemic outcome. Current evidence suggests that aging and age-releated comorbidities impair the cardioprotective effects of conditionings. In conjuction with aging, decrease in melatonin synthesis from pineal gland can have role in the pathogenesis of aging and age-related cardiovascular diseases. In this study, we investigated the effects of remote ischemic perconditioning (RIPerC) and physiological and pharmacological concentrations of melatonin on the infarct size, Fas gene, cytochrome b-245 beta chain (Cybb) gene, nuclear factor-kappa B (NfκB), and irisin using an in vivo model of myocardial ischemia/reperfusion (I/R) injury. Sprague-Dawley rats that were divided into two groups first as non-pinealectomized (Non-Px) and pinealectomized (Px), and then (a) Control; (b) I/R (30-minute ischemia, 120-minute reperfusion caused by left coronary artery ligation); (c) I/R + RIPerC (when myocardial ischemia initiated, three cycles of 5-minute occlusion followed by 5-minute reperfusion); (d) I/R + Mel; (e) Px; (f) Px + I/R; (g) Px + I/R + RIPerC; (h) Px + I/R + RIPerC + Mel groups. The infarct size was determined by TTC staining and analyzed by the ImageJ program. Molecular parameters were evaluated by qRT-PCR and Western blot. Results showed that increased infarct size in Non-Px groups decreased with RIPerC and melatonin. However, increased infarct size in Px groups was decreased minimally with RIPerC and significantly decreased with RIPerC + Melatonin. Fold change in Fas gene was associated with the infarct size. RIPerC and melatonin reduced expressions of Cybb, NfκB, and irisin genes. The physiological release and pharmacological concentration of melatonin may improve protective effect of RIPerC against I/R-induced infarct size by modulating Cybb, Fas, NfκB, Irisin signaling pathways.

IL-1β receptor antagonist (IL-1Ra) combined with autophagy inducer (TAT-Beclin1) is an effective alternative for attenuating extracellular matrix degradation in rat and human osteoarthritis chondrocytes

Background

Autophagy induction is an effective approach for OA therapy. IL-1β is one of the major inflammatory cytokines linked to OA pathological progression, and its receptor blockade interrupts OA cartilage destruction. The objective of this study was to decipher the link between autophagy and regulatory mechanism of IL-1β and to investigate the effect of IL-1β receptor blockade by IL-1 receptor antagonist (IL-1Ra) combined with or without an autophagy inducer (TAT-Beclin1) on extracellular matrix (ECM) in OA chondrocytes in vitro and in vivo.

Methods

IL-1β-treated rat and human OA chondrocytes were cultured in response to IL-1Ra. The expression and distribution of signal molecules regulating ECM synthesis and autophagy were investigated via western blotting, immunoprecipitation, real-time PCR, immunofluorescence, and transmission electron microscope technique. Furthermore, after intra-articular injection of IL-1Ra, TAT-Beclin1, and a combination of both in a rat OA model established by anterior cruciate ligament transection and medial meniscus resection, the morphological changes of cartilage and related signal molecule expression levels were monitored using H.E., Safranin O-Fast green, and immunohistochemistry staining.

Results

Reduced autophagy by IL-1β contributed to ECM degradation, and blockade of IL-1β by IL-1Ra restored autophagy and attenuated ECM degradation in rat and human OA chondrocytes, as well as in a rat OA model. Akt/mTOR/ULK1, Akt/mTOR/NF-κB, and LC3B deacetylation were involved in autophagy regulated by IL-1β. Intra-articular injection of IL-1Ra combined with TAT-Beclin1 was more effective than IL-1Ra alone.

Conclusions

IL-1Ra restored autophagy and attenuated ECM degradation, with an implication that blocking IL-1β combined with enhancing autophagy might be a potential therapeutic strategy for OA.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1952-5) contains supplementary material, which is available to authorized users.

AMPK-mediated degradation of Nav1.5 through autophagy

The voltage-gated cardiac sodium channel, Nav1.5, is the key component that controls cardiac excitative electrical impulse and propagation. However, the dynamic alterations of Nav1.5 during cardiac ischemia and reperfusion (I/R) are seldom reported. We found that the protein levels of rat cardiac Nav1.5 were significantly decreased in response to cardiac I/R injury. By simulating I/R injury in cells through activating AMPK by glucose deprivation, AMPK activator treatment, or hypoxia and reoxygenation (H/R), we found that Nav1.5 was down-regulated by AMPK-mediated autophagic degradation. Furthermore, AMPK was found to phosphorylate Nav1.5 at threonine (T) 101, which then regulates the interaction between Nav1.5 and the autophagic adaptor protein, microtubule-associated protein 1 light chain 3 (LC3), by exposing the LC3-interacting region adjacent to T101 in Nav1.5. This study highlights an instrumental role of AMPK in mediating the autophagic degradation of Nav1.5 during cardiac I/R injury.-Liu, X., Chen, Z., Han, Z., Liu, Y., Wu, X., Peng, Y., Di, W., Lan, R., Sun, B., Xu, B., Xu, W. AMPK-mediated degradation of Nav1.5 through autophagy.

Cyclosporin A Protected Cardiomyocytes Against Oxidative Stress Injury by Inhibition of NF-κB Signaling Pathway

PURPOSE

This study aims to investigate the effects and the molecular mechanism of cyclosporin A (CsA) against oxidative stress injury in cultured neonatal rat cardiomyocytes.

METHODS

Bax/Bcl-2, cl-casp-9/casp-9, cl-casp-3/casp-3, and iNOS/β-actin ratios and p-IκB and IκB levels were analyzed by western blot. IL-1β and TNF-α levels were analyzed by ELISA.

RESULTS

CsA effectively improved the cell viability and reduced the extracellular lactate dehydrogenase release in cardiomyocytes after H₂O₂-induced oxidative damage. CsA significantly increased the superoxide dismutase activity, glutathione production, and catalase activity but decreased the malonaldehyde level. CsA treatment considerably reduced the H₂O₂-induced intracellular generation of reactive oxygen species, mitochondrial dysfunction, and release of cytochrome c. CsA could act against H₂O₂-induced ATP reduction, TCA cycle enzymes, mitochondrial complex I enzyme, and complex V enzyme in cardiomyocytes. CsA significantly decreased the Bax/Bcl-2 ratio, cl-casp-9/casp-9, and cl-casp-3/casp-3 in a concentration-dependent manner. CsA also remarkably reduced the cleaved PARP level and DNA fragmentation. NF-κB was closely related to oxidative stress injury. CsA inhibited NF-κB activation, thereby preventing the upregulation of IL-1β, TNF-α, iNOS, and intracellular NO release.

CONCLUSIONS

CsA protected cardiomyocytes against H₂O₂-induced cell injury. Hence, CsA may be developed as a candidate drug to prevent or treat myocardial ischemia reperfusion injury.

Anti-renal fibrosis effect of asperulosidic acid via TGF-β1/smad2/smad3 and NF-κB signaling pathways in a rat model of unilateral ureteral obstruction

BACKGROUND

Renal fibrosis is the most common pathway leading to end-stage renal disease. It is characterized by excess extracellular matrix (ECM) accumulation and renal tissue damage, subsequently leading to kidney failure. Asperulosidic acid (ASPA), a bioactive iridoid glycoside, exerts anti-tumor, anti-oxidant, and anti-inflammatory activities, but its effects on renal fibrosis induced by unilateral ureteral obstruction (UUO) have not yet been investigated.

PURPOSE

This study aimed to investigate the protective effect of ASPA on renal fibrosis induced by UUO, and to explore its pharmacological mechanism.

METHODS

Thirty-six Sprague-Dawley (SD) rats were randomly divided into six groups: sham group, UUO model group, three ASPA treatment groups (10, 20, and 40 mg/kg), and captopril group (20 mg/kg). Rats were administered vehicle, ASPA or captopril intraperitoneally once a day for 14 consecutive days. Urea nitrogen (BUN), uric acid (UA) and inflammatory factors in serum samples were evaluated on the 7th, 10th, and 14th day after renal fibrosis induction. In addition, the 12 h urine was collected to test the content of urinary protein (upro) on the 14th day. The obstructive renal tissues were collected for pathological analysis (hematoxylin and eosion (H&E) staining and Masson's Trichrome staining) and immunohistochemical analysis on the 14th day after renal fibrosis induction. The mRNA expression of related factors and the protein levels of smad2, smad3, and smad4 were measured in UUO-induced rats by real time PCR and Western blot, respectively.

RESULTS

The levels of BUN, UA, and upro were elevated in UUO-induced rats, but ASPA treatment improved renal function by reducing the levels of BUN, UA, and upro. The protein levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6, as well as the mRNA levels of TNF-α, IL-1β, IL-6, monocyte chemoattractant protein-1 (MCP-1) and interferon-γ (IFN-γ), were decreased after ASPA administration (10, 20 and 40 mg/kg) in a dose-dependent manner. The ASPA exerted an alleviation effect on the inflammatory response through inhibition of nuclear factor-kappa B (NF-κB) pathway. In addition, reductions in α-smooth muscle actin (α-SMA), collagen III, and fibronectin expression were observed after ASPA administration at doses of 20 and 40 mg/kg. Furthermore, the renal expression of transforming growth factor-β1 (TGF-β1), smad2, smad3, and smad4 was down-regulated by ASPA treatment at doses of 20 and 40 mg/kg.

CONCLUSION

ASPA possessed protective effects on renal interstitial fibrosis in UUO-induced rats. These effects may be through inhibition of the activation of NF-κB and TGF-β1/smad2/smad3 signaling pathways.

Snapshot: Implications for mTOR in Aging-related Ischemia/Reperfusion Injury

Aging may aggravate the damage and dysfunction of different components of multiorgan and thus increasing multiorgan ischemia/reperfusion (IR) injury. IR injury occurs in many organs and tissues, which is a major cause of morbidity and mortality worldwide. The kinase mammalian target of rapamycin (mTOR), an atypical serine/threonine protein kinase, involves in the pathophysiological process of IR injury. In this review, we first briefly introduce the molecular features of mTOR, the association between mTOR and aging, and especially its role on autophagy. Special focus is placed on the roles of mTOR during ischemic and IR injury. We then clarify the association between mTOR and conditioning phenomena. Following this background, we expand our discussion to potential future directions of research in this area. Collectively, information reviewed herein will serve as a comprehensive reference for the actions of mTOR in IR injury and may be significant for the design of future research and increase the potential of mTOR as a therapeutic target.

mTOR and Beclin1: Two key autophagy-related molecules and their roles in myocardial ischemia/reperfusion injury

Autophagy is the general term of lysosomal degradation of substances in cells, which is considered the key to maintaining the normal structure and function of the heart. It also has a correlation with several heart diseases, in particular, myocardial ischemia/reperfusion (I/R) injury. At the stage of myocardial ischemia, autophagy degrades nonfunctional cytoplasmic proteins providing the critical nutrients for the critical life activities, thereby suppressing cell apoptosis and necrosis. However, autophagy is likely to affect the heart negatively in the reperfusion stage. Mammalian target of rapamycin (mTOR) and Beclin1 are two vital autophagy-related molecules in myocardial I/R injury playing significant roles in different stages. In the ischemia stage, mTOR plays its roles through AMPK/mTOR and phosphoinositide 3-kinase/Akt/mTOR pathway, whereas Beclin1 plays its roles through its upregulation in the reperfusion stage. A possible interaction between mTOR and Beclin1 has been reported recently, and further studies need to be done to find the underlying interaction between the two molecules in myocardial I/R injury.

Galectin-3 exacerbates ox-LDL-mediated endothelial injury by inducing inflammation via integrin β1-RhoA-JNK signaling activation

Oxidized low‐density lipoprotein (Ox‐LDL)‐induced endothelial cell injury plays a crucial role in the pathogenesis of atherosclerosis (AS). Plasma galectin‐3 (Gal‐3) is elevated inside and drives diverse systemic inflammatory disorders, including cardiovascular diseases. However, the exact role of Gal‐3 in ox‐LDL‐mediated endothelial injury remains unclear. This study explores the effects of Gal‐3 on ox‐LDL‐induced endothelial dysfunction and the underlying molecular mechanisms. In this study, Gal‐3, integrin β1, and GTP‐RhoA in the blood and plaques of AS patients were examined by ELISA and western blot respectively. Their levels were found to be obviously upregulated compared with non‐AS control group. CCK8 assay and flow cytometry analysis showed that Gal‐3 significantly decreased cell viability and promoted apoptosis in ox‐LDL‐treated human umbilical vascular endothelial cells (HUVECs). The upregulation of integrinβ1, GTP‐RhoA, p‐JNK, p‐p65, p‐IKKα, and p‐IKKβ induced by ox‐LDL was further enhanced by treatment with Gal‐3. Pretreatment with Gal‐3 increased expression of inflammatory factors (interleukin [IL]‐6, IL‐8, and IL‐1β), chemokines(CXCL‐1 and CCL‐2) and adhesion molecules (VCAM‐1 and ICAM‐1). Furthermore, the promotional effects of Gal‐3 on NF‐κB activation and inflammatory factors in ox‐LDL‐treated HUVECs were reversed by the treatments with integrinβ1‐siRNA or the JNK inhibitor. We also found that integrinβ1‐siRNA decreased the protein expression of GTP‐RhoA and p‐JNK, while RhoA inhibitor partially reduced the upregulated expression of p‐JNK induced by Gal‐3. In conclusion, our finding suggests that Gal‐3 exacerbates ox‐LDL‐mediated endothelial injury by inducing inflammation via integrin β1‐RhoA‐JNK signaling activation.