XJP-1, a novel ACEI, with anti-inflammatory properties in HUVECs

Identification of a Hydrogen-Sulfide-Releasing Isochroman-4-One Hybrid as a Cardioprotective Candidate for the Treatment of Cardiac Hypertrophy

Cardiac pathological hypertrophy is associated with undesirable epigenetic changes and causes maladaptive cardiac remodeling and heart failure, leading to high mortality rates. Specific drugs for the treatment of cardiac hypertrophy are still in urgent need. In the present study, a hydrogen-sulfide-releasing hybrid 13-E was designed and synthesized by appending p-hydroxythiobenzamide (TBZ), an H₂S-releasing donor, to an analog of our previously discovered cardioprotective natural product XJP, 7,8-dihydroxy-3-methyl-isochromanone-4. This hybrid 13-E exhibited excellent H₂S-generating ability and low cellular toxicity. The 13-E protected against cardiomyocyte hypertrophy In Vitro and reduced the induction of Anp and Bnp. More importantly, 13-E could reduce TAC-induced cardiac hypertrophy In Vivo, alleviate cardiac interstitial fibrosis and restore cardiac function. Unbiased transcriptomic analysis showed that 13-E regulated the AMPK signaling pathway and influenced fatty acid metabolic processes, which may be attributed to its cardioprotective activities.

A 2-Benzylmalonate Derivative as STAT3 Inhibitor Suppresses Tumor Growth in Hepatocellular Carcinoma by Upregulating β-TrCP E3 Ubiquitin Ligase

The aberrant activation of a signal transducer and activator of transcription 3 (STAT3) restrains type I interferon (IFN) α/β-induced antiviral responses and is associated with the development of cancer. Designing specific STAT3 inhibitors will thus provide new options for use as IFN therapy. Herein, we identified a novel small molecule, dimethyl 2-(4-(2-(methyl(phenyl(p-tolyl)methyl)amino)ethoxy)benzyl)malonate (CIB-6), which can inhibit the IFN-α-induced interferon stimulated response element (ISRE) luciferase reporter (IC₅₀ value = 6.4 μM) and potentiate the antiproliferative effect of IFN-α in human hepatocellular carcinoma (HCC) cells. CIB-6 was found to bind to the STAT3 Src homology 2 (SH2) domain, thereby selectively inhibiting STAT3 phosphorylation without affecting Janus kinases and STAT1/2. CIB-6 also inhibited the migration and invasion of HCC cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Mechanistically, CIB-6 reduced the expression of β-catenin (an EMT key protein) via upregulating β-transducin repeat-containing protein (β-TrCP) and curbed nuclear factor kappa-B (NF-κB) activation through restricting the phosphorylation of the inhibitor of NF-κB (IκB) kinase (IKK) via STAT3 inhibition. Treatment with CIB-6 significantly retarded tumor growth in nude mice with SK-HEP-1 xenografts. In addition, clinical sample analysis revealed that lower β-TrCP and higher β-catenin expression could affect the median survival time of HCC patients. Our findings suggest that CIB-6 could be a new therapeutic strategy for HCC therapy through STAT3-mediated β-TrCP/β-catenin/NF-κB axis.

Research progress in biological activities of isochroman derivatives

Isochromans are well recognized heterocyclic compounds in drug discovery which produce diverse therapeutically related applications in pharmacological practices. Medicinal chemistry investigators have synthesized drug-like isochroman candidates with multiple medicinal features including central nervous system (CNS), antioxidant, antimicrobial, antihypertensive, antitumor and anti-inflammatory agents. Simultaneously, SAR (Structure-Activity Relationship) analysis has drawn attentions among medicinal chemists, along with a great deal of derivatives have been derived for potential targets. In this article, we thoroughly summarize the biological activities and part of typical SAR for isochroman derivatives reported on existing literatures and patents, wishing to provide an overall retrospect and prospect on the isochroman analogues.

Bioactive secondary metabolites from an endophytic fungus Phoma sp. PF2 derived from Artemisia princeps Pamp

Two new isochromanone derivatives, (3S,4S)-3,8-dihydroxy-6-methoxy-3,4,5-trimethylisochroman-1-one (1) and methyl (S)-8-hydroxy-6-methoxy-5-methyl-4a-(3-oxobutan-2-yl)benzoate (2), together with six known compounds (3‒8) were isolated from the cultures of an endophytic fungus Phoma sp. PF2 obtained from Artemisia princeps. The chemical structures of the isolated compounds were elucidated by interpretation of spectroscopic data (1D, 2D NMR, HRESIMS, and CD) and calculation of ECD. All the isolated compounds (1‒8) showed moderate inhibitory activities on nitric oxide levels in lipopolysaccharide-induced RAW264.7 machrophage cells.

Chrysin Suppresses Vascular Endothelial Inflammation via Inhibiting the NF-κB Signaling Pathway

The vascular endothelium is a continuous layer of flat polygonal cells that are in direct contact with the blood and participate in responses to inflammation. Chrysin is a flavonoid compound extracted from plants of the genus Asteraceae with a wide range of pharmacological activities and physiological activities. Here, we studied the effects of chrysin on the regulation of the proadhesion and pro-inflammatory phenotypes of the endothelium both in vitro and in vivo. Our results revealed that chrysin strongly inhibited Tohoku Hospital Pediatrics-1 (THP-1) cell adhesion to primary human umbilical vein endothelial cells and concentration-dependently attenuated interleukin 1β-induced increases in intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin messenger RNA levels and ICAM-1 and VCAM-1 protein levels. Previous studies reported that nuclear factor κB (NF-κB) is important in the inflammatory response in endothelial cells, particularly in regulating adhesion molecules, and our data shed light on the mechanisms whereby chrysin suppressed endothelial inflammation via the NF-κB signaling pathway. In addition, our in vivo findings demonstrated the effects of chrysin in the permeability and inflammatory responses of the endothelium to inflammatory injury. Taken together, we conclude that chrysin inhibits endothelial inflammation both in vitro and in vivo, which could be mainly due to its inhibition of NF-κB signaling activation. In conclusion, chrysin may serve as a promising therapeutic candidate for inflammatory vascular diseases.

Discovery of Novel 4-Arylisochromenes as Anticancer Agents Inhibiting Tubulin Polymerization

XJP-L (8), a derivative of the natural product (±)-7,8-dihydroxy-3-methylisochroman-4-one isolated from the peel of Musa sapien tum L., was found to exhibit weak inhibitory activity of tubulin polymerization (IC₅₀ = 10.6 μM) in our previous studies. Thus, a series of 4-arylisochromene derivatives were prepared by incorporating the trimethoxyphenyl moiety into 8, among which compound (±)-19b was identified as the most potent compound with IC₅₀ values ranging from 10 to 25 nM against a panel of cancer cell lines. Further mechanism studies demonstrated that (±)-19b disrupted the intracellular microtubule network, caused G2/M phase arrest, induced cell apoptosis, and depolarized mitochondria of K562 cells. Moreover, (±)-19b exhibited potent in vitro antivascular and in vivo antitumor activities. Notably, the R-configured enantiomer of (±)-19b, which was prepared by chiral separation, was slightly more potent than (±)-19b and was much more potent than the S-configured enantiomer in both antiproliferative and antitubulin assays. Our findings suggest that (±)-19b deserves further research as a potential antitubulin agent for the treatment of cancers.

Protective effect of ulinastatin on severe pulmonary infection under immunosuppression and its molecular mechanism

The objective of the present study was to investigate the protective effect of ulinastatin on severe pulmonary infection under immunosuppression, and its molecular mechanism. Mice were treated with methylprednisolone and lipopolysaccharide (LPS) to establish the model of severe pulmonary infection under immunosuppression. Mice were randomly divided into group A (model group; treated with equal volumes of saline), group B (treated with 1×10⁵ U/kg ulinastatin), and group C (normal control group). Bronchoalveolar lavage fluid (BALF) was collected, and the concentrations of cytokines in BALF were measured by enzyme-linked immunosorbent assay (ELISA). Pathological changes in lung tissues were observed by hematoxylin and eosin (H&E) staining. The mRNA levels of M1 and M2 macrophage markers in lung tissues were detected by real-time polymerase chain reaction (PCR). Specific protein levels in lung tissues were measured by western blotting. Apoptosis in lung tissues was detected by the terminal-deoxynucleoitidyl transferase mediated nick end-labeling (TUNEL) method. The concentrations of TNF-α, IL-6, and IL-1β in BALF, the mRNA levels of the three M1 macrophage markers, and the protein levels of p-Janus Kinase 2 (p-JAK2), p-signal transducer and activator of transcription-3 (p-STAT-3), cleaved caspase-9, and cleaved poly-ADP-ribose polymerase (PARP), and the number of apoptotic cells in lung tissues in group A were significantly higher than those in groups B and C (P<0.05), whereas the concentrations of IL-4, IL-10, and IL-13 and the mRNA levels of the three M2 macrophage markers were significantly lower than those in groups B and C (P<0.05). Immunofluorescence showed that the nuclei of lung epithelial macrophages in group A became smaller and moved towards the side of nuclear membranes. In conclusion, ulinastatin can improve the inflammatory response caused by severe infection under immunosuppression, which balances the inflammatory microenvironment and inhibits apoptosis at least partially through inhibiting JAK2/STAT-3 and/or caspase pathway activity, ultimately playing a role in lung protection.

Organolithium-mediated cyclization reactions: a practical way to access hetero- and carbocycles

Cyclization reactions are considered as one of the most important reactions in organic synthesis due to the fact that natural molecules contain cyclic components either as part of the molecule or molecular skeleton.

TSG attenuates LPC-induced endothelial cells inflammatory damage through notch signaling inhibition

Lysophosphatidylcholine (LPC) induces inflammation in endothelial cells (ECs) but the mechanism is not fully understood. The Notch signaling pathway is involved in chronic EC inflammation, but its functions in LPC-induced endothelial inflammatory damage and 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside's (TSG) protective effect during LPC-induced inflammatory damage in human umbilical vein endothelial cells (HUVECs) is largely unknown. We report that Notch signaling activation contributed to LPC-induced injury in HUVECs, and that TSG protected HUVECs from LPC-induced injury by antagonizing Notch signaling activation by LPC. γ-secretase inhibitor (DAPT), a specific inhibitor of the Notch signaling pathway, and Notch1 siRNA were used to inhibit Notch activity. HUVECs were exposed to LPC in the presence or absence of TSG, DAPT, and Notch1 siRNA. LPC treatment of HUVECs resulted in reduced cell viability, and Notch1 and Hes1 upregulation. Either silencing of Notch1 by siRNA or pharmacological inhibition of Notch signaling by DAPT prevented the loss of cell viability, and induction of apoptosis, and enhanced expression Notch1, Hes1 and MCP-1 by LPC in HUVECs. Similarly, TSG reduced LPC stimulation of Notch1, Hes1, and MCP-1 expression, prevented the release of IL-6 and CRP and rescued HUVECs from LPC-induced cell damage. Our data indicate that the Notch signaling pathway is a crucial mediator of endothelial inflammatory damage and that TSG protects against endothelial inflammatory damage by inhibiting the Notch signaling pathway. Our findings suggest that targeting Notch signaling by natural products such as TSG is a promising strategy for the prevention and treatment of chronic inflammation associated diseases, including atherosclerosis. © 2015 IUBMB Life, 68(1):37-50, 2016.

Design, synthesis, biological evaluation and docking study of 4-isochromanone hybrids bearing N-benzyl pyridinium moiety as dual binding site acetylcholinesterase inhibitors

A series of novel 4-isochromanone hybrids bearing N-benzyl pyridinium moiety as dual binding site acetylcholinesterase inhibitors have been designed and synthesized. The screening results showed that most of the compounds exhibited potent anti-AChE activity in the range of nM concentrations. The 1-(4-fluorobenzyl) substituted derivative 9d exhibited the most potent anti-AChE activity with IC50 value of 8.9 nM and high AChE/BuChE selectivity (SI>230). Kinetic and molecular modeling studies suggested that compound 9d was mixed-type inhibitor, binding simultaneously to CAS and PAS of AChE. Besides, the preliminary structure-activity relationships were discussed.

Salvianolic acid A inhibits endothelial dysfunction and vascular remodeling in spontaneously hypertensive rats

AIMS

Despite the numerous pharmacological agents available for hypertension therapy, hypertension-related microvascular remodeling is not resolved, eventually leading to end-organ damage. The aim of the present study was to investigate the protection of salvianolic acid A (SalA) against microvascular remodeling in vitro and in vivo.

MAIN METHODS

Spontaneously hypertensive rats (SHRs) were administered 2.5, 5 or 10 mg/kg SalA via intraperitoneal injection once a day for 4 weeks. The tail-cuff method was applied to monitor blood pressure; the microvascular structure of the retina was detected by hematoxylin-eosin and immunohistochemical staining; the function of mesenteric arteries was measured by DMT wire myography; endothelial cell proliferation was estimated using the Cell Counting Kit-8; endothelial cell migration was evaluated by wound healing and transwell assay; and endothelial cell integrity was detected by transendothelial electrical resistance and permeability assays.

KEY FINDINGS

Although no antihypertensive effects of SalA were observed, SalA attenuated the microvascular inward remodeling of the retina and improved microvascular function in the mesenteries in vivo. Further cell experiments confirmed the beneficial effects of SalA on the integrity of the endothelial monolayer in vitro.

SIGNIFICANCE

Salvianolic acid A inhibited endothelial dysfunction and vascular remodeling in spontaneously hypertensive rats. Therefore, salvianolic acid A could be a potential drug therapy to prevent further targeted organ damage induced by vascular remodeling.

Enalapril inhibits tubulointerstitial inflammation and NLRP3 inflammasome expression in BSA-overload nephropathy of rats

AIM

Proteinuria is not only a common marker of renal disease, but also involved in renal tubulointerstitial inflammation and fibrosis. The aim of this study was to investigate the mechanisms underlying the protective effects of enalapril, an ACEI, against nephropathy in rats.

METHODS

Wistar rats underwent unilateral right nephrectomy, and then were treated with BSA (5 g·kg(-1)·d(-1), ip), or BSA plus enalapril (0.5 g·kg(-1)·d(-1), po) for 9 weeks. The renal lesions were evaluated using histology and immunohistochemistry. The expression of NLRP3, caspase-1, IL-1β and IL-18 was analyzed using immunohistochemistry, RT-PCR and Western blot.

RESULTS

BSA-overload resulted in severe proteinuria, which peaked at week 7, and interstitial inflammation with prominent infiltration of CD68(+) cells (macrophages) and CD3(+) cells (T lymphocytes), particularly of CD20(+) cells (B lymphocytes). BSA-overload markedly increased the expression of NLRP3, caspase-1, IL-1β and IL-18 in the proximal tubular epithelial cells, and in inflammatory cells as well. Furthermore, the expression of IL-1β or IL-18 was significantly correlated with proteinuria (IL-1β: r=0.757; IL-18: r=0.834). These abnormalities in BSA-overload rats were significantly attenuated by concurrent administration of enalapril.

CONCLUSION

Enalapril exerts protective effects against BSA-overload nephropathy in rats via suppressing NLRP3 inflammasome expression and tubulointerstitial inflammation.

First total synthesis of antihypertensive natural products S-(+)-XJP and R-(−)-XJP

The first total synthesis of S-(+)-XJP and R-(−)-XJP has been achieved via intramolecular Heck reaction. A latent functionality strategy was implemented to circumvent the racemization in this endeavor.

Synthesis and β-adrenergic blocking activity of oxime ether hybrids derived from a natural isochroman-4-one

AIM

In a search for new cardiovascular drug candidates, a series of novel oxime ethers derived from a natural isochroman-4-one were synthesized.

METHOD

Compounds 3 and 6, derived from the natural antihypertensive compound 7, 8-dihydroxy-3-methyl-isochroman-4-one (XJP), were designed and synthesized. Subsequently, a series of novel isochroman-4-one oxime ether hybrids were prepared by hybridizing various N-substituted isopropanolamine functionalities to isochroman-4-one oxime. Furthermore, β1-adrenergic blocking activities of the synthesized compounds were assayed using the isolated rat left atria.

RESULTS

Twenty target compounds were obtained, and the preliminary structure-activity relationships were deduced. The most promising compound Ic exhibited β1-adrenoceptor blocking activity (inhibition: 52.2%) at 10(-7) mol·L(-1), which was superior to that of propranolol (inhibition: 49.7%).

CONCLUSION

The results suggested that natural product XJP/isopropanolamine moiety hybrids may provide a promising approach for the discovery of novel cardiovascular drug candidates.

Leonurine attenuates lipopolysaccharide-induced inflammatory responses in human endothelial cells: involvement of reactive oxygen species and NF-κB pathways

Leonurine, an active alkaloid of Traditional Chinese Medicine Herba leonuri, displayed cardioprotective effects by anti-oxidative and anti-apoptotic activities in vitro and in vivo. Herein, we explored the effects and possible mechanisms of leonurine on lipopolysaccharide (LPS)-induced inflammatory responses in human umbilical vein endothelial cells (HUVEC). We found that leonurine pretreatment concentration-dependently attenuated LPS-induced mRNA expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and monocyte chemoattractant protein-1. Meanwhile, LPS-mediated expression/release of ICAM-1, VCAM-1, and cyclooxygenase-2, and tumor necrosis factor-α was also reduced by leonurine. In addition, we confirmed that leonurine suppressed degradation of IκBα and phosphorylation of nuclear factor-κB (NF-κB) p65 as well as production of intracellular reactive oxygen species in a concentration dependent manner. Furthermore, the cytoprotective enzyme heme oxygenase-1 could be upregulated in leonurine-treated HUVEC. Our present results indicated leonurine exerted beneficial effects in inflammatory conditions partly through inhibition of reactive oxygen species and NF-κB signaling pathways.