Wei-Wei Lu

Systemic cytokine profiles and splenic toll-like receptor expression during Trichinella spiralis infection

Parasitic helminth and their products can suppress or modulate the host immune response for long-term survival and continued infection. Commonly, helminth can induce conditional T helper cell type 2 (Th2) response, regulatory T cell and cytokines, and altered function of antigen presentation cells by modulating toll-like receptors (TLRs). The helminth Trichinella spiralis establishes chronic infection in skeletal muscles of a wide range of mammalian hosts. We infected mice with T. spiralis and investigated Th1/Th2/Th17 cytokine profiles in serum and expression of TLRs and related signal molecules in spleen at various times post-infection. The infection evoked a mixed Th1/Th2 and inhibited Th17 immune response, with initial predominance of a Th1 response in intestine stage and subsequent predominance of a Th2 response in muscle stage. Different stages of infection had different impacts on the expression of TLRs and related signaling molecules. In the adult stage of infection, TLR1 and TLR4 were upregulated and the MyD88-dependent signal pathway was activated. The muscle larvae inhibited TLR4 and TRIF-dependent signal pathway. Our results implied that T. spiralis infection may regulate Th1/Th2/Th17 cytokine production through TLRs.

Intermedin1-53 protects against cardiac hypertrophy by inhibiting endoplasmic reticulum stress via activating AMP-activated protein kinase.

Objective: Intermedin (IMD), a novel member of the calcitonin/calcitonin gene-related peptide family, is involved in maintaining circulatory homeostasis and is a protective factor of heart and vessel. Here, we investigated the effects of IMD on cardiac hypertrophy in vivo and in vitro and explored the mechanisms involved. Methods and results: IMD1–53 (100 ng/kg/h) was systemically administered to rats with cardiac hypertrophy induced by abdominal aortic constriction (AAC) by a mini-osmotic pump the next day after surgery continuously for 4 weeks. The AAC-treated rats before IMD infusion showed increased IMD content and expression of its receptors in the hearts. In-vivo administration of IMD1–53 greatly attenuated the cardiac hypertrophy as shown by heart weight to body weight ratio (HW/BW), haemodynamics, echocardiography, histological analyses and expression of hypertrophic markers atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) induced by AAC. IMD1–53 treatment significantly reduced the myocardial protein expression of endoplasmic reticulum stress (ERS) markers such as glucose-regulated protein 78 (GRP78), CCAAT/enhancer binding protein homologous protein (CHOP) and caspase-12, whereas the protein level of phosphorylated AMP-activated protein kinase (p-AMPK) was upregulated with IMD1–53 treatment, which was further confirmed in cultured cardiomyocytes. Concurrently, cardiomyocyte apoptosis in vivo and in vitro was ameliorated by IMD1–53 treatment. The inhibitory effects of IMD1–53 on ERS and apoptosis were eliminated on pretreatment with compound C, an AMPK inhibitor. Conclusion: IMD1–53 could exert its cardioprotective effect on cardiac hypertrophy by inhibiting myocardial ERS and apoptosis, possibly via activation of AMPK signalling.

Intermedin1-53 Protects Against Myocardial Fibrosis by Inhibiting Endoplasmic Reticulum Stress and Inflammation Induced by Homocysteine in Apolipoprotein E-Deficient Mice.

Aim: Endoplasmic reticulum stress (ERS) and inflammation participate in cardiac fibrosis. Importantly, a novel paracrine/autocrine peptide intermedin1–53 (IMD1–53) in the heart inhibits myocardial fibrosis in rats. However, the mechanisms are yet to be fully elucidated. Methods: Myocardial fibrosis in apolipoprotein E-deficient (ApoE -/-) mice and neonatal rat cardiac fibroblasts (CFs) were induced using homocysteine (Hcy). Results: IMD1–53 inhibited myocardial fibrosis in vivo and in vitro. Picrosirius red staining showed that IMD1–53 reduced myocardial interstitial collagen deposition in ApoE-/- mice treated with Hcy and decreased the expression of myocardial collagen I and III, which was further verified in rat CFs. IMD1–53 attenuated myocardial hypertrophy, as shown by cardiomyocyte cross-sectional area, ratio of heart weight to body weight, and mRNA levels of atrial natriuretic peptide and brain natriuretic peptide. IMD1–53 inhibited the upregulation of ERS hallmarkers such as glucose-regulated protein 78 (GRP78), GRP94, activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1α, spliced-X-box-binding protein-1, protein kinase receptor-like ER kinase, and eukaryotic translation initiation factor 2α in mouse myocardium and rat CFs treated with Hcy. In addition, IMD1–53 decreased the production of inflammatory factors such as tumor necrosis factor-α, monocyte chemotactic protein-1, interleukin-6 (IL-6), and IL-1β in the mouse myocardium and rat CFs treated with Hcy. Concurrently, IMD1–53 ameliorated the expression of nuclear factor-κB, transforming growth factor-β1, and c-Jun N-terminal kinase in the mouse myocardium and rat CFs treated with Hcy. Conclusions: IMD potentially protects against myocardial fibrosis induced by Hcy in ApoE-/- mice, possibly via attenuating myocardial ERS and inflammation.

Intermedin1−53 Attenuates Abdominal Aortic Aneurysm by Inhibiting Oxidative Stress

Objective—Oxidative stress plays a critical role in the development of abdominal aortic aneurysm (AAA). Intermedin (IMD) is a regulator of oxidative stress. Here, we investigated whether IMD reduces AAA by inhibiting oxidative stress. Approach and Results—In angiotensin II–induced ApoE−/− mouse and CaCl2-induced C57BL/6J mouse model of AAA, IMD1−53 significantly reduced the incidence of AAA and maximal aortic diameter. Ultrasonography, hematoxylin, and eosin staining and Verhoeff–van Gieson staining showed that IMD1−53 significantly decreased the enlarged aortas and elastic lamina degradation induced by angiotensin II or CaCl2. Mechanistically, IMD1−53 attenuated oxidative stress, inflammation, vascular smooth muscle cell apoptosis, and matrix metalloproteinase activation. IMD1−53 inhibited the activation of redox-sensitive signaling pathways, decreased the mRNA and protein expression of nicotinamide adenine dinucleotide phosphate oxidase subunits, and reduced the activity of nicotinamide adenine dinucleotide phosphate oxidase in AAA mice. Expression of Nox4 was upregulated in human AAA segments and in angiotensin II–treated mouse aortas and was markedly decreased by IMD1−53. In vitro, vascular smooth muscle cells with small-interfering RNA knockdown of IMD showed significantly increased angiotensin II–induced reactive oxygen species, and small-interfering RNA knockdown of Nox4 markedly inhibited the reactive oxygen species. IMD knockdown further increased the apoptosis of vascular smooth muscle cells and inflammation, which was reversed by Nox4 knockdown. Preincubation with IMD17−47 and protein kinase A inhibitor H89 inhibited the effect of IMD1–53, reducing Nox4 protein levels. Conclusions—IMD1−53 could have a protective effect on AAA by inhibiting oxidative stress.

Hydrogen Sulfide Inhibits Cigarette Smoke-Induced Endoplasmic Reticulum Stress and Apoptosis in Bronchial Epithelial Cells

Background: Apoptosis of lung structural cells contributes to the process of lung damage and remodeling in chronic obstructive pulmonary disease (COPD). Our previous studies demonstrated that exogenous hydrogen sulfide (H2S) can reduce the lung tissue pathology score, anti-inflammation and anti-oxidation effects in COPD, but the effect of H2S in regulating cigarette smoke (CS) induced bronchial epithelial cell apoptosis and the underlying mechanisms are not clear. Objectives: To investigate the effect of H2S on CS induced endoplasmic reticulum stress (ERS) and bronchial epithelial cell apoptosis. Methods: Male Sprague–Dawley rats randomly divided into four groups for treatment: control, CS, NaHS + CS, and propargylglycine (PPG) + CS. The rats in the CS group were exposed to CS generated from 20 commercial unfiltered cigarettes for 4 h/day, 7 days/week for 4 months. Since the beginning of the third month, freshly prepared NaHS (14 μmol/kg) and PPG (37.5 mg/kg) were intraperitoneally administered 30 min before CS-exposure in the NaHS and PPG groups. 16HBE cells were pretreated with Taurine (10 mM), 5 mmol/L 4-phenylbutyric acid (4-PBA) or NaHS (100, 200, and 400 μM) for 30 min, and then cells were exposed to 40 μmol/L nicotine for 72 h. ERS markers (GRP94, GRP78) and ERS-mediated apoptosis markers 4-C/EBP homologous protein (CHOP), caspase-3 and caspase-12 were assessed in rat lung tissues and human bronchial epithelial cells. The apoptotic bronchial epithelial cells were detected by Hoechst staining in vitro and TUNEL staining in vivo. Results: In CS exposed rats, peritoneal injection of NaHS significantly inhibited CS induced overexpression ERS-mediated apoptosis markers and upregulation of apoptotic rate in rat lungs, and inhibiting the endogenous H2S production by peritoneal injection of PPG exacerbated these effects. In the nicotine-exposed bronchial epithelial cells, appropriate concentration of NaHS and ERS inhibitors taurine and 4-PBA inhibited nicotine-induced upregulation of apoptotic rate and overexpression of ERS-mediated apoptosis markers. Conclusion: H2S inhibited lung tissue damage by attenuating CS induced ERS in rat lung and exogenous H2S attenuated nicotine induced ERS-mediated apoptosis in bronchial epithelial cells.

Inhibition of endoplasmic reticulum stress by neuregulin-1 protects against myocardial ischemia/reperfusion injury

HighlightsNRG‐1 inhibits cardiomyocyte ER stress induced by tunicamycin and dithiothreitol.NRG‐1 inhibits cardiomyocyte ER stress through ErbB4 receptor.The inhibitory effects of NRG‐1 on cardiomyocyte ER stress is through PI3K/Akt signaling pathway.NRG‐1 attenuates apoptosis and ER stress induced by H/R in cardiomyocytes.NRG‐1 reduces the myocardial I/R injury and ER stress in I/R heart. Abstract Neuregulin‐1 (NRG‐1), an endogenously produced polypeptide, is the ligand of cardiomyocyte ErbB receptors, with cardiovascular protective effects. In the present study, we explored whether the cardioprotective effect of NRG‐1 against I/R injury is mediated by inhibiting myocardial endoplasmic reticulum (ER) stress. In vitro, NRG‐1 directly inhibited the upregulation of ER stress markers such as glucose‐regulated protein 78, CCAAT/enhancer binding protein homologous protein and cleaved caspase‐12 induced by the ER stress inducers tunicamycin or dithiothreitol in both neonatal and adult ventricular myocytes. Attenuating ErbB signals by an ErbB inhibitor AG1478 or ErbB4 knockdown and preincubation with phosphoinositide 3‐kinase inhibitors all reversed the effect of NRG‐1 inhibiting ER stress in cultured neonatal rat cardiomyocytes. Concurrently, cardiomyocyte ER stress and apoptosis induced by hypoxia‐reoxygenation were decreased by NRG‐1 treatment in vitro. Furthermore, in an in vivo rat model of myocardium ischemia/reperfusion (I/R), intravenous NRG‐1 administration significantly decreased ER stress and myocardial infarct size induced by I/R. NRG‐1 could protect the heart against I/R injury by inhibiting myocardial ER stress, which might be mediated by the phosphoinositide 3‐kinase/Akt signaling pathway.

Endoplasmic reticulum stress-mediated apoptosis is activated in intestines of mice with Trichinella spiralis infection.

Gastrointestinal helminth infection, including Trichinella spiralis, initiates a series of intestinal structural, cellular and physiological changes. Intestinal invasion is an important stage of trichinellosis because it determines the development and subsequent course of the disease and its consequences. Apoptosis mediated by endoplasmic reticulum stress (ERS) plays a key role in infectious diseases, but the effect of T. spiralis infection on inducing apoptosis in the small intestine has been neglected. We investigated apoptosis and changes in ERS-associated apoptosis molecules in the intestine of mice with T. spiralis infection. TUNEL staining and detection of the apoptotic marker cleaved caspase 3 revealed that apoptosis occurred in the mouse intestine at days 3 and 7 post-infection. The ER chaperone 78-kDa glucose-regulated protein (GRP78) was upregulated at days 3 and 7 post-infection. The ERS-associated apoptosis molecules C/EBP homologous protein, cleaved caspase 12 and c-Jun NH2-terminal kinase were upregulated at days 3 and 7, days 3, 7 and 10 and days 7 and 10 post-infection, respectively. Thus, apoptosis occurred in the intestine of mice with T. spiralis infection, and the ERS-mediated apoptosis pathway was activated by infection with this small intestine dwelling nematode.

Inhibition of endoplasmic reticulum stress by intermedin1-53 attenuates angiotensin II–induced abdominal aortic aneurysm in ApoE KO Mice

Endoplasmic reticulum stress (ERS) is involved in the development of abdominal aortic aneurysm (AAA). Since bioactive peptide intermedin (IMD)1-53 protects against AAA formation, here we investigated whether IMD1–53 attenuates AAA by inhibiting ERS. AAA model was induced by angiotensin II (AngII) in ApoE KO mouse background. AngII-treated mouse aortas showed increased ERS gene transcription of caspase12, eukaryotic translation initiation factor 2a (eIf2a) and activating transcription factor 4(ATF4).The protein level of ERS marker glucose regulated protein 94(GRP94), ATF4 and C/EBP homologous protein 10(CHOP) was also up-regulated by AngII. Increased ERS levels were accompanied by severe VSMC apoptosis in human AAA aorta. In vivo administration of IMD1-53 greatly reduced AngII-induced AAA and abrogated the activation of ERS. To determine whether IMD inhibited AAA by ameliorating ERS, we used 2 non-selective ERS inhibitors phenyl butyrate (4-PBA) and taurine (TAU). Similar to IMD, PBA, and TAU significantly reduced the incidence of AAA and AAA-related pathological disorders. In vitro, AngII infusion up-regulated CHOP, caspase12 expression and led to VSMC apoptosis. IMD siRNA aggravated the CHOP, caspase12-mediated VSMC apoptosis, which was abolished by ATF4 silencing. IMD infusion promoted the phosphorylation of adenosine 5‘-monophosphate (AMP)-activated protein kinase (AMPK) in aortas in ApoE KO mice, and the AMPK inhibitor compound C abolished the protective effect of IMD on VSMC ERS and apoptosis induced by AngII. In conclusion, IMD may protect against AAA formation by inhibiting ERS via activating AMPK phosphorylation.

Intermedin1-53 attenuates abdominal aortic aneurysm by inhibiting oxidative stress

Abdominal aortic aneurysm (AAA), a progressive aortic dilation, is a common vascular disease associated with high mortality. Although conventional treatments including surgery or percutaneous intervention are performed in highrisk patients, effective medical therapies for AAA have not been developed. The hallmark pathological features of AAA are typified by intense oxidative stress, inflammation, matrix degradation, and apoptosis of vascular smooth muscle cells (VSMCs). Reactive oxygen species (ROS) are thought to be a common link between inflammation, matrix degradation, and VSMC apoptosis, so reducing ROS may be a therapeutic target of AAA. In animal models of AAA, genetic and pharmacological inhibition of ROS suppressed aneurysm formation. A major source of ROS in vascular tissue is the membrane-bound nicotinamide vadenine dinucleotide phosphate (NADPH) oxidase, which contains transmembrane subunits such as Nox1–5, Duox1 and Duox2, and p22phox and cytosolic subunits such as p47phox, p67phox, Rac1, and optionally p40phox (for Nox2) or the respective homologs of p47phox and p67phox, NOXO1 and NOXA1 (for Nox1). These subunits assemble to form a functional oxidase. NADPH oxidase activity was markedly upregulated in human aneurysmal aortas. Inhibition of NADPH oxidase attenuated AAA formation, which suggests that NADPH oxidase plays a critical role in AAA formation. Nox1 and Nox4 are the 2 Nox isoforms expressed in VSMCs, where ROS are mainly generated in AAA. Nox4 has been shown to produce hydrogen peroxide (H 2 O 2 ), which induced apoptosis in VSMCs. Nox4-mediated oxidative stress may participate in the pathogenesis of AAA. Paracrine/autocrine factors are involved in maintaining circulatory homeostasis and mediating the pathogenesis of cardiovascular diseases. Some of these factors such as adrenomedullin (ADM) can antagonize oxidative stress and have properties of anti-inflammation, suppression of proliferation, and migration of VSMCs as well as promotion of growth and reparation of endothelium. Thus, investigation of endogenous peptides may help reveal new mechanisms and therapeutic strategies for AAA.