Structure-based optimization of Toddacoumalone as highly potent and selective PDE4 inhibitors with anti-inflammatory effects

Phosphodiesterase-4 (PDE4) is an important drug target for inflammatory diseases. Previously, we identified a series of novel PDE4 inhibitors derived from the natural Toddacoumalone, among which the hit compound 2 with a naphthyridine scaffold showed moderate potency with the IC₅₀ value of 400 nM. Based on the co-crystal structure of PDE4D-2, further structural optimizations and structure-activity relationship studies led to a highly potent PDE4 inhibitor 23a with the IC₅₀ value of 0.25 nM and excellent selectivity profiles over other PDEs (>4000-fold). The co-crystal structure of PDE4D-23a elucidated that 23a has strong interactions with the M and Q pocket of PDE4D. Importantly, compound 23a significantly inhibits the release of inflammatory cytokines TNF-α and IL-6 in lipopolysaccharide-stimulated RAW264.7 cells. Thus, compound 23a with a naphthyridine scaffold is a promising PDE4 inhibitor for the treatment of inflammatory diseases.

Optimization of ultrasound extraction of Tribulus terrestris L. leaves saponins and their HPLC-DAD-ESI-MSn profiling, anti-inflammatory activity and mechanism in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Tribulus terrestris L., as an annual herb plant from Zygophyllaceae, exhibits many biological activities, and its main chemical constituents are saponins. However, the extraction process, chemical compositions, anti-inflammatory effect and mechanism of total saponins from Tribulus terrestris L. leaves are still unclear.

AIM OF THE STUDY

The present study extensively evaluated the extraction process, major components, anti-inflammatory action and mechanism of Tribulus terrestris L. leaves saponins.

MATERIALS AND METHODS

The ultrasonic extraction and response surface methods were adopted for optimization of extraction technology of total saponins from Tribulus terrestris L. leaves, and its compositions were detected with LC-MSⁿ method. The anti-inflammatory activity of total saponins was studied by lipopolysaccharide induced RAW 264.7 cells and acute lung injury mice models.

RESULTS

The ultrasonic extraction parameters of saponins fraction, including ethanol concentration 30%, extraction time 55 min, ratio of solvent to material 35:1 ml/g and extraction temperature 46 °C, were screened by response surface method with the extracting rate 5.49%, and thirty compositions were detected with LC-MSⁿ method. Moreover, saponins fraction can play a stronger anti-inflammatory effect by reducing the phagocytic activity and pulmonary edema, and protection of morphology of RAW 264.7 cells and lung tissues, and decreasing the content of NO and TNF-α. Moreover, it was revealed that total saponins extract can exert the anti-inflammatory action by the inhibition of the activation of the TLR4-TRAF6-NF-κB signalling pathway.

CONCLUSION

These studies imply that Tribulus terrestris L. leaves saponins may be an important anti-inflammatory drug in clinic.

Anti-inflammatory action of betulin and its potential as a dissociated glucocorticoid receptor modulator

Although the medical application of betulin has been presented in previous studies, the potential mechanism of the anti-inflammatory action of betulin should be further investigated. This work aims to confirm the hypothesis that betulin has dexamethasone-like anti-inflammatory action through glucocorticoid receptor (GR)-mediated pathway. Firstly, the binding ability of betulin with GR was measured by a fluorescence polarization-based competitive binding assay, with the IC₅₀ value of 79.18 ± 0.30 mM. Betulin could bind to GR and then induced GR nuclear translocation, but lacked GR transcriptional activity in HeLa cells. Hence, betulin exhibited the potential to be a dissociated modulator for GR, with the loss of glucocorticoid response element (GRE)-associated side effects. In addition, betulin downregulated GRE-driven protein expression of G6P involved in gluconeogenesis, namely side effect. The results of pro-inflammatory cytokines analysis showed that betulin exerted anti-inflammatory action in vitro. Both of the hydrophobic and hydrogen-bonding interactions stabilized the binding between betulin and GR during the simulation process. In conclusion, betulin might be a potential dissociated GR modulator with a reduced side effect profile yet keeping its anti-inflammatory action.

Therapeutic use of Guggulsterone in COVID-19 induced obesity (COVIBESITY) and significant role in immunomodulatory effect

COVID-19 has emerged as a major cause of health crisis around the world. Psychosocial, Behavioral and metabolic changes especially weight gain, among variety of population was produced in this pandemic, through variety of mechanisms. Hyperlipidemia is one of the major issues that result in serious cardiovascular complications. Governmental strategies to minimize the spread of COVID-19 through closures, lockdowns, and alterations in social interaction have complicated weight management efforts. And immunity being the need of the hour has to be improved to prevent the infection. Guggulsterone (GS) isomers are major bioactive compounds present in Commiphora mukul and Commiphora wighti. Guggulsterone shows anti-hyperlipidemic, anti-oxidant, anti-inflammatory, immunomodulatory and appetite regulating activity due to its peculiar characteristics. On the basis of clinical evidence, Guggulsterone seems to possess good cholesterol lowering, appetite regulating as well as immunomodulatory activity which can be beneficial during the pandemic of COVID-19.

Adenovirus-mediated overexpression of sST2 attenuates cardiac injury in the rat with severe acute pancreatitis

AIMS

Severe acute pancreatitis (SAP) is a serious disease associated with systematic inflammation and multiple organs dysfunction. Soluble ST2 (sST2), a member of the Toll interleukin (IL)-1 receptor (TIR) superfamily, has been demonstrated to exert immune-regulatory and anti-inflammatory properties in several inflammation-related diseases. In this study, we investigated whether transfer of sST2 gene by adenovirus vector could attenuate sodium taurocholate-induced SAP and associated cardiac injury.

MAIN METHODS

A rat model of SAP was induced by retrograde injection of 5% sodium taurocholate (1 ml/kg) into the biliopancreatic duct. Rats in the treatment groups were intravenously injected with adenovirus expressing sST2 (Ad-sST2, 1 × 10⁹ particles/rat) or green fluorescent protein (Ad-GFP) via the tail vein 48 h before SAP induction. Histological changes in the pancreatic and heart tissues, and parameters for evaluating SAP and associated cardiac injury were determined at 24 h after SAP.

KEY FINDINGS

Sodium taurocholate induced obvious pathological changes in pancreas and elevated serum levels of amylase and lipase. Furthermore, SAP animals exhibited significant cardiac impairment, evidenced by decreased cardiac function, increased myocardial apoptosis and cardiac-related enzymes including creatine kinase isoenzyme, lactate dehydrogenase, and Troponin T. Administration of Ad-sST2 markedly improved the structure of pancreas and heart tissues, and reversed the alterations in serum amylase, lipase and cardiac-related enzymes. In addition, Ad-sST2 treatment downregulated pro-inflammatory cytokines production, demonstrating the anti-inflammatory property of sST2.

SIGNIFICANCE

Our results suggest that administration of Ad-sST2 significantly attenuated the severity of SAP and associated cardiac damage, and the cardioprotective effect is associated with its anti-inflammatory action.

Sinusoidal protection by sphingosine-1-phosphate receptor 1 agonist in liver ischemia-reperfusion injury

BACKGROUND

Functional and structural damages in sinusoidal endothelial cells (SECs) have a crucial role during hepatic ischemia-reperfusion injury (IRI). In regulating endothelial function, sphingosine-1-phosphate receptor 1 (S1PR1), which is a G protein-coupled receptor, has an important role. The present study aimed to clarify whether SEW2871, a selective S1PR1 agonist, can attenuate hepatic damage caused by hepatic IRI, focusing on SEC functions.

METHODS

In vivo, using a 60-min partial-warm IRI model, mice were treated with SEW2871 or without it (with vehicle). In vitro, isolated SECs pretreated with SEW2871 or without it (with vehicle) were incubated with hydrogen peroxide.

RESULTS

Compared with the IRI + vehicle group, SEW2871 administration significantly improved serum transaminase levels and liver damage, attenuated infiltration of Ly-6G and mouse macrophage antigen-1-positive cells, suppressed the expression of vascular cell adhesion molecule-1 and proinflammatory cytokines in the liver, and enhanced the expressions of endothelial nitric oxide synthase (eNOS) and vascular endothelial (VE) cadherin in the liver (eNOS/β-actin [median]: 0.24 versus 0.53, P = 0.008; VE-cadherin/β-actin [median]: 0.21 versus 0.94, P = 0.008). In vitro, compared with the vehicle group, pretreatment of SECs with SEW2871 significantly increased the expressions of eNOS and VE-cadherin (eNOS/β-actin [median]: 0.22 versus 0.29, P = 0.008; VE-cadherin/β-actin [median]: 0.38 versus 0.67, P = 0.008). As results of investigation of prosurvival signals, SEW2871 significantly increased Akt phosphorylation in SECs and decreased lactate dehydrogenase levels in supernatants of SECs.

CONCLUSIONS

These results indicate that S1PR1 agonist induces attenuation of hepatic IRI, which might be provided by preventing SEC damage. S1PR1 may be a therapeutic target for the prevention of early sinusoidal injury after hepatic IRI.

Very low-dose fluvastatin-valsartan combination decreases parameters of inflammation and oxidative stress in patients with type 1 diabetes mellitus

AIMS

Previously we revealed the effectiveness of a new therapeutic approach with a short-term, very-low dose fluvastatin-valsartan combination on the improvement of arterial function in type 1 diabetes mellitus patients (T1DM). In this study we explored whether this approach influences inflammation and oxidative stress and explored any association of these effects with arterial function improvement.

METHODS

This was a supplementary analysis of the two previous double blind randomized studies (included 44 T1DM patients). Treatment group received very-low dose fluvastatin-valsartan, the control group received placebo. Blood samples were collected and inflammation parameters: high-sensitivity CRP (hsCRP), interleukin 6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1) and oxidative stress parameter total antioxidant status (TAS) were measured.

RESULTS

Treatment decreased hsCRP values (by 56.5%, P<0.05) and IL-6 values (by 33.6%, P<0.05) and increased TAS values (by 21.1%; P<0.05) after 30days of treatment. High sensitivity CRP and TAS remained decreased 3months after treatment discontinuation. Importantly, the anti-inflammatory and anti-oxidative action significantly correlated with arterial function improvement.

CONCLUSIONS

The approach consisting of short-term (30days) treatment with a very low-dose fluvastatin-valsartan combination acts anti-inflammatory and anti-oxidative in T1DM patients. These observations along with the improvement of arterial function support the assumption that this approach could have an important clinical benefit in T1DM patients.

Neuroprotective effects of clarithromycin against neuronal damage in cerebral ischemia and in cultured neuronal cells after oxygen-glucose deprivation

AIMS

Rats subjected to transient focal ischemia and cultured neuronal cells subjected to oxygen-glucose deprivation (OGD) were treated with clarithromycin (CAM) to evaluate the effects of CAM in protecting against neuronal damage.

MAIN METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 90min and then reperfused. Each animal was given an oral dose clarithromycin (CAM, 100mg/kg) or vehicle alone just after the ischemia was commenced. The infarct volume, edema index and neurological performance were assessed after 24 and 72h of reperfusion. The cerebral blood flow (CBF) was measured with an MRI system at 90min after MCAO. After 24 and 72h, oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) were assessed by immunohistochemical analyses and degenerative cells were assessed in the cortex by Fluoro-Jade C (FJC) labeling. The cultured neuronal cells were also used to examine the effects of CAM exposure on the viability of the cells after OGD.

KEY FINDINGS

CBF was unchanged between the two groups. Significant reductions of the infarct volume and edema index, an improved neurological deficit score, a significant suppression of 4-HNE and 8-OHdG expression, marked reductions of Iba-1 and TNF-α expression, and a significant reduction of FJC-positive cells were also observed in the CAM-treated animals at both time points. Treatment with 10μM and 100μM CAM in vitro significantly reduced cell death after OGD.

SIGNIFICANCE

CAM appears to provide antioxidant and anti-inflammatory effects and protect against neuronal damage after cerebral ischemia and OGD.

Updates in the pathophysiological mechanisms of Parkinson’s disease: Emerging role of bone marrow mesenchymal stem cells

AIM: To explore the approaches exerted by mesenchymal stem cells (MSCs) to improve Parkinson’s disease (PD) pathophysiology.

METHODS: MSCs were harvested from bone marrow of femoral bones of male rats, grown and propagated in culture. Twenty four ovariectomized animals were classified into 3 groups: Group (1) was control, Groups (2) and (3) were subcutaneously administered with rotenone for 14 d after one month of ovariectomy for induction of PD. Then, Group (2) was left untreated, while Group (3) was treated with single intravenous dose of bone marrow derived MSCs (BM-MSCs). SRY gene was assessed by PCR in brain tissue of the female rats. Serum transforming growth factor beta-1 (TGF-β1), monocyte chemoattractant protein-1 (MCP-1) and brain derived neurotrophic factor (BDNF) levels were assayed by ELISA. Brain dopamine DA level was assayed fluorometrically, while brain tyrosine hydroxylase (TH) and nestin gene expression were detected by semi-quantitative real time PCR. Brain survivin expression was determined by immunohistochemical procedure. Histopathological investigation of brain tissues was also done.

RESULTS: BM-MSCs were able to home at the injured brains and elicited significant decrease in serum TGF-β1 (489.7 ± 13.0 vs 691.2 ± 8.0, P < 0.05) and MCP-1 (89.6 ± 2.0 vs 112.1 ± 1.9, P < 0.05) levels associated with significant increase in serum BDNF (3663 ± 17.8 vs 2905 ± 72.9, P < 0.05) and brain DA (874 ± 15.0 vs 599 ± 9.8, P < 0.05) levels as well as brain TH (1.18 ± 0.004 vs 0.54 ± 0.009, P < 0.05) and nestin (1.29 ± 0.005 vs 0.67 ± 0.006, P < 0.05) genes expression levels. In addition to, producing insignificant increase in the number of positive cells for survivin (293.2 ± 15.9 vs 271.5 ± 15.9, P > 0.05) expression. Finally, the brain sections showed intact histological structure of the striatum as a result of treatment with BM-MSCs.

CONCLUSION: The current study sheds light on the therapeutic potential of BM-MSCs against PD pathophysiology via multi-mechanistic actions.

Neuroprotective effects of erythromycin on ischemic injury following permanent focal cerebral ischemia in rats

OBJECTIVE

This study aims to determine if erythromycin provides neuroprotective effects against ischemic injury following permanent focal cerebral ischemia.

METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO). Each animal received a single subcutaneous injection of erythromycin lactobionate (EM, 50 mg/kg) or vehicle immediately after ischemia. The infarct volume, edema index and neurological performance were evaluated at 24 and 72 h after MCAO. The cerebral blood flow (CBF) was measured with an MRI system at 30 min after MCAO. TUNEL staining and immunohistochemical analyses for oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) in the cortex were conducted at 24 and 72 h after MCAO.

RESULTS

The CBF did not differ between the EM-treated and vehicle-treated groups. The EM treatment significantly reduced the infarct volume (p < 0.01) at 24 and 72 h after MCAO and significantly reduced the edema index (p < 0.01) at 24 h. The EM treatment significantly improved the neurological deficit scores (p < 0.05) at 24 and 72 h. EM also significantly suppressed the accumulation of 4-HNE (p < 0.01) and 8-OHdG (p < 0.01) and markedly reduced Iba-1 (p < 0.01) and TNF-α expression (p < 0.05) at both time points. The EM treatment significantly reduced TUNEL-positive cells (p < 0.01) at both time points.

CONCLUSION

These findings suggest that EM can protect against the neuronal damage caused by cerebral ischemia by alleviating inflammation and reducing oxidant stress.

In vitro functional response of human tendon cells to different dosages of low-frequency pulsed electromagnetic field

PURPOSE

Chronic tendinopathy is a degenerative process causing pain and disability. Current treatments include biophysical therapies, such as pulsed electromagnetic fields (PEMF). The aim of this study was to compare, for the first time, the functional in vitro response of human tendon cells to different dosages of PEMF, varying in field intensity and duration and number of exposures.

METHODS

Tendon cells, isolated from human semitendinosus and gracilis tendons (hTCs; n = 6), were exposed to different PEMF treatments (1.5 or 3 mT for 8 or 12 h, single or repeated treatments). Scleraxis (SCX), COL1A1, COL3A1 and vascular endothelial growth factor-A (VEGF-A) expression and cytokine production were assessed.

RESULTS

None of the different dosages provoked apoptotic events. Proliferation of hTCs was enhanced by all treatments, whereas only 3 mT-PEMF treatment increased cell viability. However, the single 1.5 mT-PEMF treatment elicited the highest up-regulation of SCX, VEGF-A and COL1A1 expression, and it significantly reduced COL3A1 expression with respect to untreated cells. The treated hTCs showed a significantly higher release of IL-1β, IL-6, IL-10 and TGF-β. Interestingly, the repeated 1.5 mT-PEMF significantly further increased IL-10 production.

CONCLUSIONS

1.5 mT-PEMF treatment was able to give the best results in in vitro healthy human tendon cell culture. Although the clinical relevance is not direct, this investigation should be considered an attempt to clarify the effect of different PEMF protocols on tendon cells, in particular focusing on the potential applicability of this cell source for regenerative medicine purpose, both in surgical and in conservative treatment for tendon disorders.

Antidermatophytic Activity of Mikania micrantha Kunth: An Invasive Weed

CONTEXT

The incidence of dermatophytosis has risen dramatically in recent years. Limited availability of side-effect free drugs has led to a search for new antidermatophytic agents.

OBJECTIVE

The objective was to investigate antidermatophytic activity and in vitro anti-inflammatory activity (protease inhibition assay) of whole plant (aerial parts only) of Mikania micrantha.

MATERIALS AND METHODS

The dried and powdered aerial parts of M. micrantha were extracted separately with petroleum ether, ethyl acetate and methanol. Antidermatophytic activity was determined by agar tube dilution method against Epidermophyton floccosum var. nigricans, Microsporum canis, Microsporum gypseum and Trichophyton rubrum. The activities of various parts of the plant - flowers, leaves and stem were separately analyzed using their ethyl acetate extract. Fungicidal efficacy and trypsin inhibiting activity of the whole plant, flowers and leaves were also analyzed using the ethyl acetate extracts.

STATISTICAL ANALYSIS USED

For trypsin inhibition assay results are expressed as mean ± standard division. For antidermatophytic assay, the significance of the difference between control and test was analyzed statistically using Fisher's exact test.

RESULTS

Ethyl acetate extract of M. micrantha exhibited excellent antidermatophytic activity, followed by petroleum ether and methanolic extracts. Ethyl acetate extracts of whole plant, flowers, leaves and stem completely inhibited the growth of dermatophytes at the tested concentration of 2 mg/mL. Furthermore, ethyl acetate extracts of whole plant, leaves and flowers were fungicidal, and the percentages of trypsin inhibition exhibited were 33.73 ± 0.306, 39.0 ± 0.505 and 35.53 ± 0.503, respectively.

CONCLUSIONS

Since M. micrantha possesses antidermatophytic as well as anti-inflammatory activities, the plant is an excellent candidate for the development of new medicaments against dermatophytoses in traditional as well as modern medicine.

Propolis and its constituent caffeic acid suppress LPS-stimulated pro-inflammatory response by blocking NF-κB and MAPK activation in macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action.

MATERIALS AND METHODS

The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets.

RESULTS

Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential.

CONCLUSIONS

Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs.

Simultaneous monitoring of superoxides and intracellular calcium ions in neutrophils by chemiluminescence and fluorescence: evaluation of action mechanisms of bioactive compounds in foods

We have developed a measuring system for simultaneous monitoring of chemiluminescence and fluorescence, which indicate respectively, (i) generation of superoxide anion radicals (O2(-•)) and (ii) change in the intracellular calcium ion concentration ([Ca(2+)]i) of neutrophils triggered by the mechanism of innate immune response. We applied this measuring system for establishing a method to distinguish between anti-inflammatory actions and antioxidant actions caused by bioactive compounds. We evaluated anti-inflammatory agents (zinc ion [Zn(2+)] and ibuprofen) and antioxidants (superoxide dismutase [SOD] and ascorbic acid). It was shown that ibuprofen and Zn(2+) were anti-inflammatory while SOD and ascorbic acid were anti-oxidative. We conclude that it is possible to determine the mechanism of action of bioactive compounds using this method.