α-Asarone blocks 7β-hydroxycholesterol-exposed macrophage injury through blocking elF2α phosphorylation and prompting beclin-1-dependent autophagy

Cinnamaldehyde ameliorates STZ-induced diabetes through modulation of autophagic process in adipocyte and hepatic tissues on rats

Type 2 diabetes mellitus is a worldwide public health issue. In the globe, Egypt has the ninth-highest incidence of diabetes. Due to its crucial role in preserving cellular homeostasis, the autophagy process has drawn a lot of attention in recent years, Therefore, the purpose of this study was to evaluate the traditional medication metformin with the novel therapeutic effects of cinnamondehyde on adipocyte and hepatic autophagy in a model of high-fat diet/streptozotocin-diabetic rats. The study was conducted on 40 male albino rats, classified into 2 main groups, the control group and the diabetic group, which was subdivided into 4 subgroups (8 rats each): untreated diabetic rats, diabetic rats received oral cinnamaldehyde 40 mg/kg/day, diabetic rats received oral metformin 200 mg/kg/day and diabetic rats received a combination of both cinnamaldehyde and metformin daily for 4 weeks. The outcomes demonstrated that cinnamaldehyde enhanced the lipid profile and glucose homeostasis. Moreover, Cinnamaldehyde had the opposite effects on autophagy in both tissues; by altering the expression of genes that control autophagy, such as miRNA 30a and mammalian target of rapamycin (mTOR), it reduced autophagy in adipocytes and stimulated it in hepatic tissues. It may be inferred that by increasing the treatment efficacy of metformin and lowering its side effects, cinnamaldehyde could be utilized as an adjuvant therapy with metformin for the treatment of type 2 diabetes.

Purple perilla frutescens extracts containing α-asarone inhibit inflammatory atheroma formation and promote hepatic HDL cholesterol uptake in dyslipidemic apoE-deficient mice

BACKGROUND/OBJECTIVES

Dyslipidemia causes metabolic disorders such as atherosclerosis and fatty liver syndrome due to abnormally high blood lipids. Purple perilla frutescens extract (PPE) possesses various bioactive compounds such as α-asarone, chlorogenic acid and rosmarinic acid. This study examined whether PPE and α-asarone improved dyslipidemia-associated inflammation and inhibited atheroma formation in apolipoprotein E (apoE)-deficient mice, an experimental animal model of atherosclerosis.

MATERIALS/METHODS

ApoE-deficient mice were fed on high cholesterol-diet (Paigen's diet) and orally administrated with 10-20 mg/kg PPE and α-asarone for 10 wk.

RESULTS

The Paigen's diet reduced body weight gain in apoE-deficient mice, which was not restored by PPE or α-asarone. PPE or α-asarone improved the plasma lipid profiles in Paigen's diet-fed apoE-deficient mice, and despite a small increase in high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein (LDL)-cholesterol, and very LDL were significantly reduced. Paigen's diet-induced systemic inflammation was reduced in PPE or α-asarone-treated apoE-deficient mice. Supplying PPE or α-asarone to mice lacking apoE suppressed aorta atherogenesis induced by atherogenic diet. PPE or α-asarone diminished aorta accumulation of CD68- and/or F4/80-positive macrophages induced by atherogenic diet in apoE-deficient mice. Treatment of apoE-deficient mice with PPE and α-asarone resulted in a significant decrease in plasma cholesteryl ester transfer protein level and an increase in lecithin:cholesterol acyltransferase reduced by supply of Paigen's diet. Supplementation of PPE and α-asarone enhanced the transcription of hepatic apoA1 and SR-B1 reduced by Paigen's diet in apoE-deficient mice.

CONCLUSIONS

α-Asarone in PPE inhibited inflammation-associated atheroma formation and promoted hepatic HDL-C trafficking in dyslipidemic mice.

Research progress on mechanism of Chinese Kaiqiao herbs in management of neuropathic pain

The Chinese herbal medicine for Kaiqiao, such as borneol, musk, grassleaf sweetflag rhizome, storax and camphor, have been prescribed in traditional Chinese medicine for thousands of years and now are widely used for neuropathic pain, the main components of which are annular compounds. Studies have shown that their analgesic mechanisms include regulating the expression of γ-aminobutyric acid, N-methyl- D-aspartic acid and other receptors; regulating ion channel function; inhibiting inflammatory response, oxidative stress and apoptosis; regulating neurotransmission and neuronal excitability; and participating in neuroprotection and neurological repair. It is suggested that the mechanisms of action of Kaiqiao herbs in central nervous system analgesia should be further explored; high-quality rapid screening of drug targets may be used, and the targeted agents using the characteristics of Kaiqiao herbs would be developed. This article reviews the research progress on the effect mechanism of traditional Kaiqiao herbs in the treatment of neuropathic pain to provide further research directions.

α-Asarone Attenuates Osteoclastogenesis and Prevents Against Oestrogen-Deficiency Induced Osteoporosis

Osteoporosis (OP) is defined as low bone mineral density which features over activated osteoclasts (OCs) and bone resorption. Targeting excessive OCs activity is thought to be an effective therapeutic approach for OP treatment. α-asarone (ASA), a compound from the traditional Chinese medicinal herb Acorus tatarinowii, has been widely used as a therapeutic agent against several diseases such as epilepsy, cough, bronchitis and asthma for many years. Recently, it was reported that ASA-derived lignins which were purified from Acorus tatarinowii root tissues effectively suppressed both RANKL-induced osteoclastogenesis and bone resorption. Besides, a classic Chinese formulation Bajitianwan (BJTW) which consisted of root and rhizome of Acorus tatarinowii Schott also showed positive effects on age-related bone loss. In the present study, we aimed to study the effects of ASA on osteoclastogenesis in vitro and in vivo. As illustrated by TRAP staining, ASA was capable of inhibiting RANKL-induced osteoclastogenesis in a dose-dependent manner, not only at an early-stage, but also in the late-stage. Besides, it also effectively suppressed bone resorption of mature OCs in a pit resorption assay. The formation of F-actin ring during osteoclastogenesis, which was important in OCs bone-resorption, was impaired as well. Subsequent mechanism experiments exposed that ASA inhibited osteoclastogenesis related genes in a time-dependent manner through AKT, p38 and NF-κB, followed by NFATc1/c-fos signaling pathway. Notably, our in vivo study uncovered that ASA was capable of improving the bone microstructure in oestrogen-deficiency induced OP models. Thus, our current work highlighted the important role of an old drug ASA in bone metabolism especially in OCs differentiation. ASA may find its potential as a lead compound to treat excessive OCs activity-induced bone loss diseases and more structure optimization is further needed.

Molecular Mechanisms and Therapeutic Potential of α- and β-Asarone in the Treatment of Neurological Disorders

Neurological disorders are important causes of morbidity and mortality around the world. The increasing prevalence of neurological disorders, associated with an aging population, has intensified the societal burden associated with these diseases, for which no effective treatment strategies currently exist. Therefore, the identification and development of novel therapeutic approaches, able to halt or reverse neuronal loss by targeting the underlying causal factors that lead to neurodegeneration and neuronal cell death, are urgently necessary. Plants and other natural products have been explored as sources of safe, naturally occurring secondary metabolites with potential neuroprotective properties. The secondary metabolites α- and β-asarone can be found in high levels in the rhizomes of the medicinal plant Acorus calamus (L.). α- and β-asarone exhibit multiple pharmacological properties including antioxidant, anti-inflammatory, antiapoptotic, anticancer, and neuroprotective effects. This paper aims to provide an overview of the current research on the therapeutic potential of α- and β-asarone in the treatment of neurological disorders, particularly neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), as well as cerebral ischemic disease, and epilepsy. Current research indicates that α- and β-asarone exert neuroprotective effects by mitigating oxidative stress, abnormal protein accumulation, neuroinflammation, neurotrophic factor deficit, and promoting neuronal cell survival, as well as activating various neuroprotective signalling pathways. Although the beneficial effects exerted by α- and β-asarone have been demonstrated through in vitro and in vivo animal studies, additional research is required to translate laboratory results into safe and effective therapies for patients with AD, PD, and other neurological and neurodegenerative diseases.

Asaronic acid inhibits ER stress sensors and boosts functionality of ubiquitin-proteasomal degradation in 7β-hydroxycholesterol-loaded macrophages

BACKGROUND

Misfolded proteins are formed in the endoplasmic reticulum (ER) due to diverse stimuli including oxidant production, calcium disturbance, and inflammatory factors. Accumulation of these non-native proteins in the ER evokes cellular stress involving the activation of unfolded protein response (UPR) and the execution of ER-associated degradation (ERAD). Naturally-occurring plant compounds are known to interfere with UPR due to their antioxidant and anti-inflammatory activities, leading to inhibition of ER stress. However, there are few studies dealing with the protective effects of natural compounds on the functionality of ERAD.

PURPOSE

The current study examined whether asaronic acid enhanced ubiquitin-proteasomal degradation in J774A.1 murine macrophages exposed to 7β-hydroxycholesterol, a risk factor for atherosclerosis. Asaronic acid (2,4,5-trimethoxybenzoic acid), identified as one of purple perilla constituents, has anti-diabetic and anti-inflammatory effects. Little is known regarding the effects of asaronic acid on the ERAD process and the ubiquitin-proteasomal degradation.

METHODS AND RESULTS

Murine macrophages were incubated with 28 μM 7β-hydroxycholesterol in absence and presence of 1-20 μΜ asaronic acid for up to 24 h. Nontoxic asaronic acid in macrophage diminished the activation of the ER stress sensors of ATF6, IRE1 and PERK stimulated by 7β-hydroxycholesterol. This methoxybenzoic acid down-regulated the oxysterol-induced expression of EDEM1, OS9, Sel1L-Hrd1 and p97/VCP1, all required for the recognition, recruitment and dislocation of misfolded proteins. On the other hand, asaronic acid enhanced the ubiquitin-proteasomal degradation of non-native proteins dislocated to the cytosol by 7β-hydroxycholesterol, which entailed the induction of the chaperones of Hsp70 and CHIP and the increased colocalization of ubiquitin and proteasomes. Taken together, asaronic acid attenuated the induction of the UPR-associated sensors and the dislocation-linked transmembrane components in the ER. Conversely, this compound enhanced the proteasomal degradation of dislocated non-native proteins in concert with the chaperones of Hsp70 and CHIP through ubiquitination.

CONCLUSION

These observations demonstrate that asaronic acid may be a potent atheroprotective agent as a natural chaperone targeting ER stress-associated macrophage injury.

Extraction and purification of cis/trans asarone from Acorus tatarinowii Schott: Accelerated solvent extraction and silver ion coordination high-speed counter-current chromatography

Acorus tatarinowii Schott is a traditional Chinese medicine used to treat memory and cognitive dysfunction. Because of their efficacy and lower toxic effects, research on α- and β-asarone, the phytoconstituents, has attracted attention owing to their remarkable pharmacological activities. Silver ion coordination complexation high-speed counter-current chromatography was used to separate these isomers from A. tatarinowii extract, coupled with accelerated solvent extraction. Accelerated solvent extraction parameters were investigated with single-factor and orthogonal testing. A two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (2:1:2:1, v/v) with 0.50 mol/L silver ions was selected for separation. From 2.0 g crude extract, 1.4 g of β-asarone and 0.09 g of α-asarone were obtained with purities over 98% by sequential sample loading in 20 h. The isolated compounds were identified by electrospray ionization mass spectrometry, ¹H and ¹³C NMR. Silver ions significantly increased the separation factor and retention of the stationary phase. The chromatographic behavior indicated that cis-configuration was more strongly complexed with the silver ion. This was further demonstrated with the help of computational analysis. In conclusion, the established method could be employed to separate other cis-trans or E/Z isomers that form coordination complexes.

Acorus calamus extract and its component α-asarone attenuate murine hippocampal neuronal cell death induced by l-glutamate and tunicamycin

The Asian traditional medicinal plant Acorus calamus and its component α-asarone exhibited various biological activities, such as antiinflammation and antioxidant effects. In the present study, we investigated the in vitro effects of A. calamus extract and α-asarone on oxidative stress- and endoplasmic reticulum (ER) stress-induced cell death in hippocampal HT22 cells. A. calamus extract and α-asarone both significantly suppressed cell death induced by the oxidative stress inducer l-glutamate and ER stress inducer tunicamycin. A. calamus extract and α-asarone also significantly reduced reactive oxygen species (ROS) production induced by l-glutamate. Moreover, A. calamus extract and α-asarone suppressed the phosphorylation of protein kinase RNA-like ER kinase (PERK) induced by tunicamycin. These results suggest that A. calamus extract and α-asarone protect hippocampal cells from oxidative stress and ER stress by decreasing ROS production and suppressing PERK signaling, respectively. α-Asarone has potential as a potent therapeutic candidate for neurodegenerative diseases, including Alzheimer's disease.

Alpha-asarone Improves Cognitive Function of APP/PS1 Mice and Reducing Aβ42, P-tau and Neuroinflammation, and Promoting Neuron Survival in the Hippocampus

Alzheimer's disease (AD) is a progressive neurodegenerative disease most often characterized by memory impairment and cognitive decline. Alpha-asarone has been reported to have the potential to treat AD. Our previous studies have found that alpha-asarone improves aged rats' cognitive function by alleviating neuronal excitotoxicity via type A gamma-aminobutyric acid (GABA) receptors. GABA level's change, neuroinflammation, and dysfunctional autophagy are found to be associated with AD. However, the effect of alpha-asarone on cognitive function of APP/PS1 transgenic mice and its underlying mechanism in terms of aggregation of amyloid-β42 (Aβ₄₂) and phosphorylated tau (p-tau), glutamic acid decarboxylase (GAD) level, neuroinflammation, and autophagy are unclear. Accordingly, we attempted to explore whether alpha-asarone improves AD mice's cognitive function and alleviates pathological symptoms by regulating GAD level, inhibiting neuroinflammation, or restore autophagy. We found that alpha-asarone enhanced spatial learning memory and decreased Aβ₄₂ and p-tau levels without influencing the GAD level in APP/PS1 transgenic mice. Also, it decreased the GFAP expression and reduced pro-inflammatory cytokines levels, thus alleviating neuroinflammation. Furthermore, alpha-asarone decreased the excess number of autophagosomes and promoted hippocampal neurons' survival. In conclusion, the results confirmed the therapeutic effect of alpha-asarone on AD-related astrogliosis, dysfunctional autophagy, and neuronal damage, which indicates its great potential to treat AD.

Silica dust exposure induces autophagy in alveolar macrophages through switching Beclin1 affinity from Bcl-2 to PIK3C3

Increased deposition of silica dust in pulmonary interstitial tissues leads to silicosis, in which autophagy plays a defensive role in silica dust-associated stress response and cell death. Our previous studies revealed that silica dust exposure contributed to autophagy in pulmonary macrophages in vivo, while the specific regulatory mechanism is still unclear. This study aimed to figure out the regulatory mechanism as well as the role of autophagy in the pathogenesis of experimental silicosis. We used 3-methyladenine (3-MA) and ABT-737 to suppress the expression of phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3) and B cell leukemia/lymphoma 2 (Bcl-2), two critical initiators of autophagy, and detected and evaluated the autophagy in NR8383 cells with or without silica dust exposure. We found that exposure of silica dust increased autophagy in NR8383 cells and elevated the expression of Beclin1 and PIK3C3, but it reduced the expression of Bcl-2. The relationship among Beclin1, PIK3C3, and Bcl-2 were then investigated using immunoprecipitation analysis, and we found that suppression of PIK3C3 and/or Bcl-2 using 3-MA and/or ABT-737 could alter the autophagy induced by silica dust in NR8383 cells, and the complexes of Beclin1/PIK3C3 and Beclin1/Bcl-2 were both downregulated, which may be that inhibition of PIK3C3 and Bcl-2 altered the affinity of Beclin1 with PIK3C3 and Bcl-2 and lead to the silence of PIK3C3 signaling. These findings indicate that silica dust exposure induces autophagy via changing the connectivity of Beclin1 from Bcl-2 to PIK3C3.

Lentiviral-Mediated Beclin-1 Overexpression Inhibits Cell Proliferation and Induces Autophagy of Human Esophageal Carcinoma Eca109 Cell Xenograft in Nude Mice

BACKGROUND

Esophageal carcinoma is one of the common malignant tumors in digestive tract. BECLIN-1 is a key gene that regulates autophagy, and its abnormal expression may be related with many human tumors. However, the mechanism of BECLIN-1 in esophageal carcinoma remains unknown.

OBJECTIVE

In this study, we explored the effect of BECLIN-1 overexpression on tumor growth in mice with esophageal carcinoma and its mechanism.

METHODS

Recombined lentiviral vector containing BECLIN-1 was used to transfect human esophageal carcinoma Eca109 cells and establish stable cell line. qRT-PCR was used to detect BECLIN-1 mRNA level in the transfected Eca109 cells, CCK-8 assay was used to detect cell proliferation. Beclin-1, P62 and LC3-II protein expression levels in Eca109 cells were detected using Western blot analysis. Subcutaneous xenograft nude mice model of human esophageal carcinoma was established, and the tumor growths in Beclin-1 group, control group and empty vector group were monitored. Beclin-1 protein expression in vivo was detected by immunohistochemistry.

RESULTS

Beclin-1 mRNA and protein were overexpressed in Eca109 cells. Compared with empty vector group, the growth rate of cells transfected with BECLIN-1 decreased significantly. Compared with the control group and empty vector group, the expression level of P62 protein in beclin-1 group was significantly decreased, while the expression level of LC3-II protein was significantly increased. The tumor growth rate in nude mice of Beclin-1 group was significantly lower than that of the control group and empty vector group, and Beclin-1 protein was mainly expressed in Beclin-1 group in vivo.

CONCLUSION

BECLIN-1 can induce autophagy in esophageal carcinoma Eca109 cells, and it can significantly inhibit the growth of esophageal carcinoma.

The composition of a bioprocessed shiitake (Lentinus edodes) mushroom mycelia and rice bran formulation and its antimicrobial effects against Salmonella enterica subsp. enterica serovar Typhimurium strain SL1344 in macrophage cells and in mice

Background

Human infection by pathogenic Salmonella bacteria can be acquired by consuming of undercooked meat products and eggs. Antimicrobial resistance against antibiotics used in medicine is also a major concern. To help overcome these harmful effects on microbial food safety and human health, we are developing novel antimicrobial food-compatible formulations, one of which is described in the present study.

Methods

The composition of a bioprocessed (fermented) rice bran extract (BPRBE) from Lentinus edodes liquid mycelia culture was evaluated using gas chromatography and mass spectrometry, and the mechanism of its antibacterial effect against Salmonella Typhimurium, strain SL1344 was investigated in macrophage cells and in mice.

Results

BPRBE stimulated uptake of the bacteria into RAW 264.7 murine macrophage cells. Activation of the cells was confirmed by increases in NO production resulting from the elevation of inducible nitric oxide synthase (iNOS) mRNA, and in protein expression. Salmonella infection down-regulated the expression of the following protein biomarkers of autophagy (a catabolic process for stress adaptation of cellular components): Beclin-1, Atg5, Atg12, Atg16, LC3-I and LC3-II. BPRBE promoted the upregulation of protein expressions that induced bacterial destruction in autolysosomes of RAW 264.7 cells. ELISA analysis of interferon IFN-β showed that inflammatory cytokine secretion and bactericidal activity had similar profiles, suggesting that BPRBE enhances cell-autonomous and systemic bactericidal activities via autophagic capture of Salmonella. The treatment also elicited increased excretion of bacteria in feces and their decreased translocation to internal organs (cecum, mesenteric lymph node, spleen, and liver).

Conclusions

The antibiotic mechanism of BPRBE involves the phagocytosis of extracellular bacteria, autophagic capture of intracellular bacteria, and prevention of translocation of bacteria across the intestinal epithelial cells. The new bioprocessing combination of mushroom mycelia and rice brans forms a potentially novel food formulation with in vivo antimicrobial properties that could serve as a functional antimicrobial food and medical antibiotic.

Is autophagy associated with diabetes mellitus and its complications? A review

Diabetes mellitus (DM) is an endocrine disorder. In coming decades it will be one of the leading causes of death globally. The key factors in the pathogenesis of diabetes are cellular injuries and disorders of energy metabolism leading to severe diabetic complications. Recent studies have confirmed that autophagy plays a pivotal role in diabetes and its complications. It has been observed that autophagy regulates the normal function of pancreatic β cells and insulin-target tissues, such as skeletal muscle, liver, and adipose tissue. This review will summarize the regulation of autophagy in diabetes and its complications, and explore how this process would emerge as a potential therapeutic target for diabetes treatment.

The lncRNA HULC functions as an oncogene by targeting ATG7 and ITGB1 in epithelial ovarian carcinoma

Highly upregulated in liver cancer (HULC) is a long noncoding RNA (lncRNA), which has recently been identified as a key regulator in the progression of hepatocellular carcinoma, gliomas and gastric cancer. However, its role in epithelial ovarian carcinoma (EOC) remains unknown. In this study, HULC expression was examined in EOC, borderline and benign ovarian tumors, and normal ovarian tissues by RT-PCR. Ovarian cancer cell phenotypes, as well as autophagy-associated proteins were examined after HULC overexpression or downregulation by plasmid or small interfering RNA (siRNA) transfection, respectively. LncRNA-protein interactions were examined by ribonucleoprotein immunoprecipitation (RIP) assays. We found that HULC expression levels were higher in EOC tissues than normal samples. HULC overexpression induced cell proliferation, migration, invasion, whereas reduced cell apoptosis in vitro and induced tumor growth in vivo. In contrast, downregulation of HULC by siRNA transfection reduced cell proliferation, migration and invasion, and induced cell apoptosis and autophagy. Our results showed that HULC overexpression reduced ATG7, LC3-II and LAMP1 expression, while inducing SQSTM1 (P62) and ITGB1 expression. HULC downregulation had the opposite effects. Furthermore, RIP indicated that ATG7 interacted with HULC; ATG7 downregulation also induced cell proliferation, reduced apoptosis and inhibited autophagy in vitro by reducing LC3-II and LAMP1 expression, while inducing SQSTM1 expression. Furthermore, ATG7 co-transfection with HULC reversed the oncogenic effects of HULC both in vitro and in vivo; however, downregulating ATG7 did not affect cell migration and invasive ability. We found that ITGB1 siRNA co-transfection with HULC reversed the function of HULC in inducing ovarian cancer cell migration and invasive ability. Taken together, our results show that HULC may promote ovarian carcinoma tumorigenesis by inhibiting ATG7 and inducing progression by regulating ITGB1.