Enhanced upregulation of SIRT1 via pioglitazone and ligustrazine confers protection against ethanol-induced gastric ulcer in rats.

Gastric ulcer is a disturbing disease that impacts many people worldwide. Pioglitazone (Piog), a thiazolidinedione, and ligustrazine (Ligu), a natural component of Ligusticum chuanxiong possess gastroprotective properties. However, the underlying mechanism is not well elucidated. The present study aimed to investigate the gastroprotective effects of Piog (15 mg/kg, p.o.), Ligu (15 mg/kg, p.o.), and their combination against ethanol-induced gastric ulcer in rats. Omeprazole (10 mg/kg) was used as a standard. Pre-treatment for 7 days with Piog, Ligu, and (Piog+Ligu) effectively alleviated ethanol-predisposed oxidative stress and inflammation through restoring HO-1, GSH, and SOD tissue levels and decreasing elevated MDA, TNF-α, ICAM, I-NOS, and IL-1ß contents. Moreover, Piog, Ligu, and (Piog+Ligu) markedly inhibited the ethanol-induced increase of gastric NF-KB and BAX. In contrast, this pre-treatment regimen significantly accelerated protein expression of SIRT1, Nrf2, and Bcl-2, along with autophagic proteins, ATG5 and Beclin. Interestingly, macroscopic, histopathological examination and mucin content were in harmony with previous results, where pre-treatment with Piog, Ligu, and (Piog+Ligu) showed a declined mucosal injury as evidenced by the remarkable decrease of the ulcer area percentage by 62.3%, 38.7%, and 91.2%, respectively, compared to the ethanol-ulcerated group. In conclusion, Piog and Ligu exhibited remarkable gastroprotective properties. Our study was the first to show that Piog, Ligu, and (Piog+Ligu) ameliorated oxidative stress, inflammation, and apoptosis and accelerated the autophagic process via the upregulation of the upstream SIRT1 protein. It is worth mentioning that future studies are needed to pave the way for the clinical use of Piog and Ligu as gastro-protective agents.

Linagliptin and secoisolariciresinol diglucoside attenuate hyperlipidemia and cardiac hypertrophy induced by a high-methionine diet in rats via suppression of hyperhomocysteinemia-induced endoplasmic reticulum stress.

Background: Cardiac hypertrophy (CH) is one of the contributing causes of morbidity and mortality. Hyperhomocysteinemia (HHcy) is one of the diseases which may predispose hyperlipidemia and CH. Linagliptin (Lina) and secoisolariciresinol diglucoside (SDG) are known to alleviate a variety of illnesses by reducing oxidative stress and inflammation. Aim: This study aimed to study the effect of HHcy on cardiac tissues, with a special focus on endoplasmic reticulum (ER) stress as a mainstay pathophysiological pathway. In addition, our study examined the protective effect of Lina, SDG, and their combination against HHcy-induced hyperlipidemia and CH in rats. Methods: Seventy-five male Sprague-Dawley rats were randomly divided into five groups, and for 60 days, the following regimen was administered: Group I: rats received distilled water; Group II: rats received methionine (MET) (2 g/kg/day, p.o.); groups III and IV: rats received Lina (3 mg/kg/day, p.o.) and SDG (20 mg/kg/day, p.o.), respectively, followed by MET (2 g/kg/day, p.o.); Group V: rats received Lina and SDG, followed by MET (2 g/kg/day, p.o.). Results: Pretreatment with Lina, SDG, and their combination showed a significant decrease in serum levels of HHcy and an improved lipid profile compared to the MET group. Moreover, both drugs improved cardiac injury, as evidenced by the substantial improvement in ECG parameters, morphological features of the cardiac muscle, and reduced serum levels of cardiac markers. Additionally, Lina and SDG significantly attenuated cardiac oxidative stress, inflammation, and apoptosis. Furthermore, Lina, SDG, and their combination remarkably downregulated the enhanced expression of endoplasmic reticulum (ER) stress markers, GRP78, PERK, ATF-4, CHOP, NF-κB, and SREBP1c compared to the MET-group. Conclusion: Lina and SDG showed cardioprotective effects against HHcy-induced heart hypertrophy and hyperlipidemia in rats.

Sertraline Pre-Treatment Attenuates Hemorrhagic Transformation Induced in Rats after Cerebral Ischemia Reperfusion via Down Regulation of Neuronal CD163: Involvement of M1/M2 Polarization Interchange and Inhibiting Autophagy.

Cerebral ischemia reperfusion (I/R) is one of the neurovascular diseases which leads to severe brain deterioration. Haemorrhagic transformation (HT) is the main complication of ischemic stroke. It exacerbates by reperfusion, causing a more deleterious effect on the brain and death. The current study explored the protective effect of sertraline (Sert) against cerebral I/R in rats by inhibiting HT, together with the molecular pathways involved in this effect. Forty-eight wister male rats were divided into 4 groups: Sham, Sert + Sham, I/R, and Sert + I/R. The ischemic model was induced by bilateral occlusion of the common carotid artery for 20 min, then reperfusion for 24 h. Sertraline (20 mg/kg, p.o.) was administrated for 14 days before exposure to ischemia. Pre-treatment with Sert led to a significant attenuation of oxidative stress and inflammation. In addition, Sert attenuated phosphorylation of extracellular regulated kinases and nuclear factor kappa-p65 expression, consequently modulating microglial polarisation to M2 phenotype. Moreover, Sert prevented the hemorrhagic transformation of ischemic stroke as indicated by the notable decrease in neuronal expression of CD163, activity of Heme oxygenase-2 and matrix metalloproteinase-2 and 9 levels. In the same context, Sert decreased levels of autophagy and apoptotic markers. Furthermore, histological examination, Toluidine blue, and Prussian blue stain aligned with the results. In conclusion, Sert protected against cerebral I/R damage by attenuating oxidative stress, inflammation, autophagy, and apoptotic process. It is worth mentioning that our study was the first to show that Sert inhibited hemorrhagic transformation. The protective effect of sertraline against injury induced by cerebral ischemia reperfusion via inhibiting Hemorrhagic transformation.

Targeting the adenosine monophosphate-activated protein kinase signalling pathway by bempedoic acid attenuates Angiotensin II-induced cardiac remodelling in renovascular hypertension in rats.

The crosstalk between the renin-angiotensin system and Adenosine monophosphate-activated protein kinase (AMPK) gained significant interest due to their involvement in the pathogenesis of several cardiovascular diseases. Angiotensin II (Ang II) plays a crucial role in developing cardiac remodelling by inducing energy imbalance, inflammation, oxidative and endoplasmic reticulum stress, and transforming growth factor-ß (TGF-ß)-induced fibrosis. Ang II directly or through extracellular signal-regulated kinase (ERK) activation impairs AMPK signalling with well-known antioxidant, anti-inflammatory, and anti-fibrotic effects. AIM: This study aimed to investigate the role of bempedoic acid, a novel antihyperlipidemic drug, in attenuating hypertension-induced cardiac remodelling in rats by modulating Ang II-induced damage and activating the AMPK signalling pathway. METHOD: Sixty adult male Sprague Dawley rats were randomly allocated into the Sham control group, Hypertensive group, Captopril group (30 mg/kg), and Bempedoic acid group (30 mg/kg). Hypertension was induced by left renal artery ligation in all groups except the Sham control group. Treatment with captopril and bempedoic acid started 14 days post-surgy and lasted two weeks. Finally, Hemodynamic measurements and electrocardiographic examination were done followed by heart tissue samples collection for biochemical, histopathological, and immunohistochemical examinations. KEY FINDINGS: Bempedoic acid preserved the cardiac function and electrocardiogram patterns. It inhibited endoplasmic reticulum stress, exhibited antioxidant activity, and increased endothelial nitric oxide synthase activity. Bempedoic acid interfered with ERK signalling pathways, including nuclear factor-κB and TGF-ß, exerting anti-inflammatory and anti-fibrotic effects. SIGNIFICANCE: These findings indicate the cardioprotective and antihypertrophic activity of bempedoic acid, which are suggested to result from energy-independent AMPK downstream signalling activation.

Effect of bempedoic acid on angiotensin-II induced hypertension and vascular tissue remodelling in renal hypertensive rats through AMPK multiple signalling pathways modulation.

Angiotensin II (Ang II), the effector of the renin-angiotensin system (RAS), is a key player in the pathogenesis of chronic hypertension, accompanied by vascular tissue resistance, remodelling, and damage. Chronic activation of Ang II receptor 1 (AT-1R) impairs multiple cellular targets implicated in cellular protection and survival, including adenosine Monophosphate-activated protein kinase (AMPK) signalling. In addition, it induces oxidative damage, endoplasmic reticulum (ER) stress, and fibrotic changes in resistance vessels. Our study investigated the antihypertensive and antifibrotic effects of bempedoic acid, a first-in-class antihyperlipidemic drug that targets adenosine triphosphate-citrate lyase enzyme to inhibit cholesterol synthesis. We also studied the modulation of multiple AMPK signalling pathways by bempedoic acid in a chronic hypertension model in rats. Sixty male Sprague-Dawley rats were divided into four groups: sham group, hypertensive group, standard captopril group, and bempedoic treated group. All groups underwent left renal artery ligation except the sham group. Fourteen days post-surgery, captopril and bempedoic acid were administered with a dose of 30 mg/kg/day orally to captopril-standard and bempedoic acid-treated groups for two weeks, respectively. In mesenteric resistance arteries, bempedoic acid activated AMPK energy independently and augmented AMPK multiple cellular targets to adapt to Ang II-induced cellular stress. It exerted antioxidant activity, increased endothelial nitric oxide synthase, and reversed the ER stress. Bempedoic acid maintained vascular integrity and prevented vascular remodelling by inhibiting extracellular signal-regulated kinase (ERK)/transforming growth factor-ß fibrotic pathway. These effects were reflected in the improved hemodynamic measurements.

Effect of hypothyroidism on contractile performance of isolated end-stage failing human myocardium.

The relationship between hypothyroidism and the occurrence and progression of heart failure (HF) has had increased interest over the past years. The low T3 syndrome, a reduced T3 in the presence of normal thyroid stimulating hormone (TSH), and free T4 concentration, is a strong predictor of all-cause mortality in HF patients. Still, the impact of hypothyroidism on the contractile properties of failing human myocardium is unknown. Our study aimed to investigate that impact using ex-vivo assessment of force and kinetics of contraction/relaxation in left ventricular intact human myocardial muscle preparations. Trabeculae were dissected from non-failing (NF; n = 9), failing with no hypothyroidism (FNH; n = 9), and failing with hypothyroidism (FH; n = 9) hearts. Isolated muscle preparations were transferred into a custom-made setup where baseline conditions as well as the three main physiological modulators that regulate the contractile strength, length-dependent and frequency-dependent activation, as well as ß-adrenergic stimulation, were assessed under near-physiological conditions. Hypothyroidism did not show any additional significant impact on the contractile properties different from the recognized alterations usually detected in such parameters in any end-stage failing heart without thyroid dysfunction. Clinical information for FH patients in our study revealed they were all receiving levothyroxine. Absence of any difference between failing hearts with or without hypothyroidism, may possibly be due to the profound effects of the advanced stage of heart failure that concealed any changes between the groups. Still, we cannot exclude the possibility of differences that may have been present at earlier stages. The effects of THs supplementation such as levothyroxine on contractile force and kinetic parameters of failing human myocardium require further investigation to explore its full potential in improving cardiovascular performance and cardiovascular outcomes of HF associated with hypothyroidism.

Polydatin combats methotrexate-induced pulmonary fibrosis in rats: Involvement of biochemical and histopathological assessment.

Polydatin (PD) is a polyphenolic compound found naturally in many fruits such as grapes. It has anti-oxidant and anti-inflammatory activities that are of paramount importance for its pharmacological actions. This study aimed to explore possible protective effects of PD against methotrexate (MTX)-induced pulmonary fibrosis in rats. A single oral dose of MTX (14 mg/kg) per week for 2 weeks caused a significant decrease in glutathione (GSH) content with a marked increase in transforming growth factor-beta (TGF-ß), alpha-smooth muscle actin (α-SMA), pulmonary content of malondialdehyde (MDA), interleukin-1ß (IL-1ß), Hydroxyproline, tumor necrosis factor-alpha (TNF-α), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as compared with the control group. Contrarily, daily administration of PD (25, 50, and 100 mg/kg, p.o.) for 14 days concomitantly with MTX ameliorated MTX-induced pulmonary fibrosis as indicated by mitigation of the previously mentioned biochemical parameters and histopathological changes in a dose-dependent manner. In conclusion, the protective effect of PD against pulmonary fibrosis induced by MTX in rats might be attributed to its anti-oxidant, anti-inflammatory as well as anti-fibrotic effects.

Ethyl pyruvate attenuates isoproterenol-induced myocardial infarction in rats: Insight to TNF-α-mediated apoptotic and necroptotic signaling interplay.

The current study investigated the prophylactic effect of ethyl pyruvate (EP) in Isoproterenol (ISO) - induced myocardial infarction (MI). Ethyl pyruvate (EP) was given at a dose of 100 mg/kg i.p for 7 days, while isoproterenol (ISO) was administered at a dose of 10 mg/kg s.c. on the 6th and 7th days to induce MI. All parameters were assessed 24 and 48 h following treatment. Interestingly, EP pre-treatment significantly improved ISO-induced hemodynamic alterations and remarkably ameliorated serum levels of cardiac injury markers, Cardiac Troponin I (cTnI) and Cardiac Creatine Kinase (CK-MB). Also, EP notably suppressed levels of oxidative stress markers, total antioxidants (TAO) and malondialdehyde (MDA) as compared to ISO-treated group. Cardioprotective effects of EP were confirmed by histopathological examination. Moreover, EP remarkably attenuated ISO-induced elevation in Tumor Necrosis Factor Alpha (TNF-α) and Nuclear factor kappa-B p65 (NF-κB) expression, along with Interleukin-6 (IL-6), Monocyte chemoattractant protein 1 (MCP-1) and Inducible nitric oxide synthase (i-NOS) levels. Also, EP significantly diminished expression of apoptotic markers; caspase 8, cleaved caspase 3 and apoptotic regulator; cellular FLICE-like inhibitory protein (cFLIP). Finally, EP notably mitigated necroptotic mediators, phosphorylated receptor-interacting serine/threonine protein kinase 1 and 3 (p-RIPK1 and p-RIPK3), phosphorylated mixed lineage kinase domain-like protein (p-MLKL) and heat shock protein 70 (HSP 70) expression as compared to the ISO-treated group. Our study was the first to investigate the effect of EP on the necroptotic signaling. Taken together, EP conferred its cardioprotective effect against ISO-induced MI partially through mitigation of TNF-α and its downstream inflammatory, apoptotic and necroptotic signaling pathways.

Dapagliflozin, an SGLT2 inhibitor, ameliorates acetic acid-induced colitis in rats by targeting NFκB/AMPK/NLRP3 axis.

The development of effective treatment strategies has been hindered by the complex pathogenesis of ulcerative colitis (UC). UC patients treated with current therapeutic approaches experienced either treatment failure or suffered excessive adverse reactions. Overactivity of NLRP3 inflammasome enhances inflammation, resulting in aggravation of colonic damage. We were interested in exploring, for the first time, the potential coloprotective effect of dapagliflozin (DPZ) on acetic acid-induced UC in rats in comparison with 5-ASA. DPZ improved histologic and macroscopic features of colon tissues and prolonged survival of UC rats. DPZ also prevented colon shortening and declined disease activity. Additionally, DPZ lessened colon tissue neutrophil content and improved antioxidant defense machinery. Further, DPZ specifically declined the colonic inflammatory marker IL-6 and upregulated the anti-inflammatory cytokine IL-10. The pyroptosis process is constrained in consequence of the repressed caspase-1 activity and caspase-1-dependent release of the bioactive cytokines IL-1ß and IL-18. These protective effects might be attributed to that DPZ on the one hand, prevented the priming step (signal 1) of NLRP3 inflammasome activation as revealed by modulating NFκB/AMPK interplay and on the other hand, inhibited the activation step (signal 2) as indicated by interrupting NLRP3/caspase-1 signaling. Since DPZ was found to be safe and well tolerated by healthy volunteers with no evidence of hypoglycemia, it might show promise in the future management of UC. However, further investigations are warranted to confirm the reversal of injury and that the coloprotective effect is substantial.

Mechanistic insights into the protective effects of chlorogenic acid against indomethacin-induced gastric ulcer in rats: Modulation of the cross talk between autophagy and apoptosis signaling.

BACKGROUND: This study aimed to investigate the gastroprotective effect of chlorogenic acid (CGA) against Indomethacin (IND)-induced gastric ulcer (GU) in rats and its underlying mechanism, especially through autophagic and apoptotic pathways. METHODS: Seventy-five rats were divided into five groups; control, IND (50 mg/kg, p.o.), CGA (100 mg/kg, p.o., 14 days), IND pretreated with CGA (50 mg/kg or 100 mg/kg, p.o., 14 days). The stomach tissues were examined to calculate the ulcer index and analyze markers of autophagy (beclin-1, LC3-II/LC3-I and p62), lysosomal function (cathepsin-D) and apoptosis (Bcl-2, Bax and caspase-3), along with expression of Akt/mTOR pathway using western blot or ELISA techniques. In addition, viability of gastric mucosal cells was detected by flowcytometry. Structural changes were assessed histologically, while autophagic and apoptotic changes of gastric mucosa were observed by transmission electron microscopy. RESULTS: CGA exhibited a dose-dependent gastroprotective effect by reversing IND-induced accumulation of autophagic vacuoles, significant reduction in beclin-1, LC3-II/LC3-I, and p62 levels, and down-regulation of p-Akt/p-mTOR expression. CGA100 also restored normal autolysosomal function by modulation of cathepsin-D levels. Furthermore, pretreatment with CGA100 was significantly associated with an increase in antiapoptotic protein Bcl-2 along with a decrease in proapoptotic Bax and caspase-3 proteins in such a way that impairs IND-induced apoptosis. This was confirmed by CGA-induced significant decrease in annexin V+ cells. CONCLUSIONS: The natural compound CGA offers a novel gastroprotective intervention against IND-induced GU through restoration of normal autophagic flux, impairment of apoptosis in a crosstalk mechanism mediated by Akt/mTOR pathway reactivation, and alleviation of IND-induced lysosomal dysfunction.

Acetyl-11-keto-ß-boswellic acid prevents testicular torsion/detorsion injury in rats by modulating 5-LOX/LTB4 and p38-MAPK/JNK/Bax/Caspase-3 pathways.

AIMS: Testicular torsion/detorsion (T/D) is a critical medical condition that necessitates prompt surgical intervention to avoid testicular atrophy and infertility. The use of natural compounds may protect against the associated detrimental oxidative stress and inflammatory responses. Interestingly, acetyl-11-keto-ß-boswellic acid (AKBA), the main active constituent of Boswellia resin, has shown potent inhibitory effect on 5-lipoxygenase enzyme which converts arachidonic acid into inflammatory mediators. Therefore, this study was conducted to assess the protective mechanisms by which AKBA may protect against testicular T/D injury in rats. MAIN METHODS: Male rats were randomly distributed into five groups: Sham, AKBA (50 mg/kg, p.o.), unilateral testicular T/D, AKBA at two dose levels (25 or 50 mg/kg for 15 successive days) followed by T/D. Histological examination and Johnsen's score were performed to assess testicular injury and perturbations in spermatogenesis. Biochemical parameters included markers of testicular function (serum testosterone), oxidant/antioxidant status (malondialdehyde, glutathione), inflammation (5-lipoxygenase, leukotriene-B4, myeloperoxidase, interleukin-1ß, interleukin-6), apoptosis (Bax, Bcl2, caspase-3), DNA integrity (quantitative DNA fragmentation, DNA laddering, PARP-1), energy production (ATP), in addition to p38 MAPK and JNK protein expression. KEY FINDINGS: In a dose dependent manner, AKBA significantly inhibited testicular T/D-induced upregulation of 5-LOX/LTB4 and p38-MAPK/JNK/Bax pathways and their associated downstream inflammatory and apoptotic cascades. These effects were accompanied with ATP replenishment and DNA preservation, resulting ultimately in salvage of the testis. SIGNIFICANCE: Unprecedentedly, the present mechanistic study revealed the pathways by which AKBA may inhibit testicular T/D injury and offered a novel protective approach that may attenuate the severity of this condition.

Lixisenatide Reduced Damage in Hippocampus CA1 Neurons in a Rat Model of Cerebral Ischemia-Reperfusion Possibly Via the ERK/P38 Signaling Pathway.

Glucagon-like peptide-1 (GLP-1) is a gut-derived peptide that has various physiological actions. One of its main actions is the regulation of blood glucose level when it is elevated as it potentiates insulin release. It is also known that GLP-1 protects neurons from damage caused by neurodegenerative diseases. Lixisenatide is one of the GLP-1 analogues that has a strong affinity to the GLP-1 receptor. Experimental animal studies have shown that it holds a neuroprotective effect in Parkinson, myocardial, and cerebral ischemic disease animal models. The beneficial effect of lixisenatide on the brain after cerebral ischemia-reperfusion (I/R) is not clarified yet; thus, it needs further explanatory studies. Our research is the first to study the effect of lixisenatide on myeloperoxidase (MPO) and toll-like receptors (TLRs)/mitogen-activated protein kinase (MAPK) pathway in a rat model of cerebral I/R. Lixisenatide with 2 doses 0.7 and 7 nmol/kg was given intraperitoneal in 2 different groups for 14 days; then, the bilateral common carotid artery was occluded for 1 h followed by reperfusion for 1 h. Examination of hippocampus CA1 neurons by Nissl stain showed that the number of intact neurons was elevated in the lixisenatide-treated group related to the control group (I/R group). Lixisenatide exhibited neuroprotection action possibly via downregulation of MPO, TLR2/4, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and pP38 and upregulation of phosphorylated extracellular signal-regulated kinase (pERK1/2); thus, this study gives possible link between lixisenatide and TLR/MAPK pathway following cerebral I/R and supports the use of lixisenatide for neuroprotection against stroke.

ERK activation by zeranol has neuroprotective effect in cerebral ischemia reperfusion.

AIMS: Incidence of stroke increases in postmenopausal women with dangerous consequences. In this study we used zeranol to protect ovariectomized (OVX) rats against cerebral I/R damage and our target is to identify the mechanism of its protection, in addition to investigating whether this mechanism inhibits inflammation (by preventing glial cell activation) and apoptosis. MAIN METHODS: First 18 ovariectomized rats were allocated into 3 groups: I/R group, zeranol+ I/R group and U0126, MEK1/2 inhibitor + zeranol+ I/R group. After 24 h reperfusion, protein expression of total extracellular signal-regulated protein kinase (t-ERK1/2), phosphorylated extracellular signal-regulated protein kinase (p-ERK1/2), Bcl-2, and Bax were quantified. Second 36 female rats were allocated into 3 groups: sham group, I/R group (after ovariectomy by 7 weeks, rats exposed to cerebral I/R) and zeranol group (after ovariectomy by 2 weeks, rats received zeranol for 5 weeks). After 24 h of reperfusion, the following parameters were measured; total nitrate/nitrite, interleukin-10, myeloperoxidase, caspase-3, and finally immunohistochemistry analysis of glial fibrillary acidic protein, cyclooxygenase-2 in cortex and hippocampus (CA1) regions were performed. KEY FINDINGS: U-0126 administration reversed the neuroprotective effect induced by zeranol through decreasing ratio of p-ERK1/2:ERK1/2 and Bcl-2/Bax in brain tissue. Activation of ERK signaling pathway by zeranol caused reduction in brain apoptosis and inflammation. SIGNIFICANCE: Zeranol showed protective effect in OVX rats that were exposed to cerebral I/R by activation of ERK signaling pathway which was blocked by U0126. This protective effect in turns led to decrease inflammation and apoptosis.

Protective effects of febuxostat against paraquat-induced lung toxicity in rats: Impact on RAGE/PI3K/Akt pathway and downstream inflammatory cascades.

AIMS: The herbicide paraquat causes fatal lung toxicity by induction of xanthine oxidase, production of free radicals and inflammation. Febuxostat, a xanthine oxidase inhibitor and anti-gout has recently shown anti-inflammatory activity. Accordingly, this study was carried out to investigate whether febuxostat may attenuate paraquat-induced lung toxicity and to explore the possible underlying mechanisms. MAIN METHODS: Rats were administered either vehicle, a single dose of paraquat (30 mg/kg, i.p.), febuxostat (15 mg/kg, oral), or both for 14 successive days. Serum LDH and sRAGE were estimated. Lung tissue xanthine oxidase activity, SOD, TAC, MDA, and RAGE, HMGB1 gene expression, PI3K/Akt and ß-catenin protein expression, MMP-9, IL-8, VEGF and COX-2 gene expression were estimated. KEY FINDINGS: Results showed that paraquat induced lung injury characterized by enhanced oxidative stress and inflammation, upregulated RAGE, HMGB1 gene expression, PI3K/Akt and ß-catenin protein expression. Administration of febuxostat inhibited the deleterious effects of paraquat on lung through inhibition of xanthine oxidase activity and related oxidative stress, downregulation of RAGE/PI3K/Akt pathway, and suppression of ß-catenin protein expression and its downstream inflammatory mediators. SIGNIFICANCE: The present study showed that febuxostat may abrogate paraquat-induced lung toxicity and demonstrated a novel mechanism for its ameliorative effects.

The protective effect of zeranol in cerebral ischemia reperfusion via p-CREB overexpression.

AIMS: Cerebral ischemia reperfusion (I/R) is a neurovascular disease leading to cerebral damage. It was found that postmenopausal women are liable to more dangerous effects than men at same age in stroke. The objective of this study is to investigate the neuroprotective effect of zeranol against cerebral ischemia reperfusion in ovariectomized rats. MAIN METHODS: 36 female wistar rats divided in to 3 groups: sham group, I/R group (where I/R was induced 7 weeks after ovariectomy), zeranol group (0.5 mg/kg every 3 days for 5 weeks before I/R). Cerebral ischemia reperfusion (I/R) was performed by bilateral common carotid artery occlusion then de-ligated to restore blood flow. After 24 h of reperfusion, rats performed cylinder test to evaluate behavioral dysfunction followed by decapitation. Brain tissues were collected for biochemical measures such as oxidative stress marker malondialdehyde, antioxidant markers reduced glutathione, inflammatory markers (interleukin-1 beta, tumor necrosis factor alpha, and inducible nitric oxide synthase), matrix metalloproteinase-9, adenosine triphosphate, brain derived neurotrophic factor, glucose transporter-3, phosphorylated c-AMP response element binding protein and finally nissl staining for histopathological examination. KEY FINDINGS: The zeranol administered group showed a reversal of neuronal damage caused by ischemia evidenced by the decrease in MDA, IL-1ß, TNF-α, and MMP-9 levels, increase GSH, and ATP levels, decrease expression of iNOS in both regions cortex and hippocampus, increase protein level of p-CREB, GLUT-3 and BDNF, increase number of intact neuron cells in both regions and attenuated histological changes in both cortex and hippocampus regions. SIGNIFICANCE: Zeranol has neuroprotective potential against cerebral ischemia reperfusion in ovariectomized rats.

Assessment of PKA and PKC inhibitors on force and kinetics of non-failing and failing human myocardium.

AIMS: Heart failure (HF) is a prevalent disease that is considered the foremost reason for hospitalization in the United States. Most protein kinases (PK) are activated in heart disease and their inhibition has been shown to improve cardiac function in both animal and human studies. However, little is known about the direct impact of PKA and PKC inhibitors on human cardiac contractile function. MATERIAL AND METHODS: We investigated the ex vivo effect of such inhibitors on force as well as on kinetics of left ventricular (LV) trabeculae dissected from non-failing and failing human hearts. In these experiments, we applied 0.5 µM of H-89 and GF109203X, which are PKA and PKC inhibitors, respectively, in comparison to their vehicle DMSO (0.05%). KEY FINDINGS AND CONCLUSION: Statistical analyses revealed no significant effect for H-89 and GF109203X on either contractile force or kinetics parameters of both non-failing and failing muscles even though they were used at a concentration higher than the reported IC50s and Kis. Therefore, several factors such as selectivity, concentration, and treatment time, which are related to these PK inhibitors according to previous studies require further exploration.

Human Placenta Expresses α2-Adrenergic Receptors and May Be Implicated in Pathogenesis of Preeclampsia and Fetal Growth Restriction.

α2-Adrenergic receptors (α2ARs) are G-protein-coupled receptors involved in catecholamine signaling by extracellular regulated protein kinase 1 and 2 (ERK1/2) pathways. We examined placental expression and function of α2AR subtypes in women with severe preeclampsia (sPE) with and without intrauterine growth restriction (IUGR). Placental biopsies were analyzed from 52 women with i) sPE (n = 8); ii) sPE + IUGR (n = 9); iii) idiopathic IUGR (n = 8); iv) idiopathic preterm birth (n = 16); and v) healthy term controls (n = 11). Expression of α2AR subtypes (α2A, α2B, α2C) and phospho-ERK1/2 (receptor activation marker) was investigated by immunohistochemistry and/or quantitative real-time RT-PCR. The effects of α2CAR knockdown on syncytialization (syncytin-1 and -2) and ß-human chorionic gonadotropin secretion were examined in BeWo cells stimulated with forskolin. The effects of α2AR agonist UK 14,304 and specific α2CAR antagonist were tested, using a trophoblast migration assay. All three α2ARs were expressed and functionally active in human placenta with site-specific localization. Highest α2BAR and α2CAR mRNA expression was identified in sPE + IUGR. α2CAR knockdown increased expression of syncytin-1 and -2 but decreased secretion of ß-human chorionic gonadotropin. UK 14,304 impaired trophoblast migration. The observed α2AR expression pattern suggests different function for each subtype. α2CAR modulates trophoblast syncytialization and migration and may carry pathogenic role in sPE + IUGR.

Sitagliptin attenuates intestinal ischemia/reperfusion injury via cAMP/PKA, PI3K/Akt pathway in a glucagon-like peptide 1 receptor-dependent manner.

AIMS: This study investigated the effect of sitagliptin prophylactic treatment on intestinal I/R rat model and explored the possible underlying mechanism. MAIN METHODS: Forty-five male Sprague-Dawley rats were randomly assigned to 3 groups: Sham group (operation without clamping), I/R group (operation with clamping) and sitagliptin pretreated group (300 mg/kg/day; p.o.) for 2 weeks before I/R insult. Intestinal I/R was performed by clamping the superior mesenteric artery for 30 min, followed by 60 min reperfusion after removal of clamping. At the end of the experimental period, all rats were sacrificed for histopathological, biochemical, PCR and western blot assessment. KEY FINDINGS: Pretreatment with sitagliptin remarkably alleviated the pathological changes induced by I/R in the jejunum, suppressed upregulated NF-κB, TNF-α, IL-1ßand MPO caused by I/R. Moreover, sitagliptin decreased the Bax/Bcl-2 ratio and accordingly suppressed apoptotic tissue damage as reflected by a caspase-3 level reduction in rat intestine subjected to I/R injury. Interestingly, sitagliptin could obviously increase the active GLP-1 level and GLP-1 receptor mRNA expression in the jejunum of I/R rats. This was associated with the augmentation of the cAMP level and enhancement of PKA activity. Simultaneously, sitagliptin treatment was able to increase the protein expression levels of phosphorylated PI3K and Akt. SIGNIFICANCE: Sitagliptin has shown protective effects against intestinal I/R injury in rats through reduction of intestinal inflammation and apoptosis. The molecular mechanisms may be partially correlated with activation of cAMP/PKA and PI3K/Akt signaling pathway by the GLP-1/GLP-1 receptor.

Dimethyl fumarate interferes with MyD88-dependent toll-like receptor signalling pathway in isoproterenol-induced cardiac hypertrophy model.

OBJECTIVES: To investigate the effect of dimethyl fumarate (DMF) on Toll-like receptor (TLR) signalling pathway in isoproterenol (ISO)-induced cardiac hypertrophy in rats. METHODS: Sixty adult male Sprague-Dawley rats were randomly allocated into three groups. group I: rats received the vehicles only; group II: rats were treated with ISO (5 mg/kg per day S.C.) to induce cardiac hypertrophy for 7 days; and group III: rats were given DMF (25 mg/kg per 12 h P.O.) for 28 days, and at the last 7 days, they were treated with ISO (5 mg/kg per day S.C.). KEY FINDINGS: Pretreatment with DMF decreased heart-to-body weight ratio, heart rate and blood pressure and improved the electrocardiographic patterns when compared with ISO group. DMF exhibited cardioprotective effect as evidenced by the reduction in cardiac troponin I, creatine kinase-MB and atrial natriuretic peptide levels. Moreover, DMF alleviated the changed oxidative stress and inflammatory biochemical markers through its anti-inflammatory and antioxidant effects. DMF interfered with TLR signalling pathway, evidenced by decreased levels of the TLR adaptor protein MyD88 and p-ERK1/2 and increased p-Akt level. CONCLUSIONS: Dimethyl fumarate exerted cardioprotective effect against ISO-induced cardiac hypertrophy. This effect is suggested to be through interfering with TLR signalling pathway.

Protein Kinase A as a Promising Target for Heart Failure Drug Development.

Heart failure (HF) is a clinical syndrome characterized by impaired ability of the heart to fill or eject blood. HF is rather prevalent and it represents the foremost reason of hospitalization in the United States. The costs linked to HF overrun those of all other causes of disabilities, and death in the United States and all over the developed as well as the developing countries which amplify the supreme significance of its prevention. Protein kinase (PK) A plays multiple roles in heart functions including, contraction, metabolism, ion fluxes, and gene transcription. Altered PKA activity is likely to cause the progression to cardiomyopathy and HF. Thus, this review is intended to focus on the roles of PKA and PKA-mediated signal transduction in the healthy heart as well as during the development of HF. Furthermore, the impact of cardiac PKA inhibition/activation will be highlighted to identify PKA as a potential target for the HF drug development.