Serpina3c deficiency induced necroptosis promotes non-alcoholic fatty liver disease through ß-catenin/Foxo1/TLR4 signaling.

Non-alcoholic fatty liver disease (NAFLD) is a public health challenge and an increasing cause of chronic liver disease worldwide. However, the underlying molecular mechanism remains unclear. The aim of this study was to determine the precise role of serpina3c in the process of NAFLD. Male Apoe-/- /serpina3c-/- double knockout (DKO) and Apoe-/- mice were fed a high-fat diet (HFD) for 12 weeks. Several markers of steatosis and inflammation were evaluated. In vitro cell models induced by palmitic acid (PA) treatment were used to evaluate the beneficial effect of serpina3c on necroptosis and the underlying molecular mechanism. Compared with Apoe-/- mice, DKO mice exhibited a significantly exacerbated hepatic steatosis, increased hepatic triglyceride content and expression of genes involved in lipid metabolism (SREBP1c and SCD1), promoted hepatic inflammation and fibrosis, promoted necroptosis by increasing expression of receptor-interacting protein 3 (RIP3), phosphorylated mixed lineage kinase domain-like (MLKL) and high mobility group box 1 (HMGB1). Notably, serpina3c deficiency increased ß-catenin, Foxo1, and Toll-like receptor 4 (TLR4) protein expression. In vitro , serpina3c knockdown promoted necroptosis and lipid droplet formation under condition of lipotoxicity. However, these phenomena were reversed by the overexpression of serpina3c. Mechanistically, downregulation of serpina3c expression promoted Foxo1 and ß-catenin colocalized in the nucleus under condition of lipotoxicity, consequently upregulating the expression of TLR4. Conversely, disruption of Foxo1-ß/catenin by Foxo1 and ß-catenin inhibitors decreased TLR4 expression and ameliorated hepatic necroptosis in vitro. This study highlights a novel mechanism that serpina3c modulates NAFLD development by inhibiting necroptosis via ß-catenin/Foxo1/TLR4.

Delivery of Mir-196c-3p with NIR-II light-triggered gel attenuates cardiomyocyte ferroptosis in cardiac ischemia-reperfusion injury.

Ferroptosis plays an important role in ischemia-reperfusion (I/R)-induced cardiac injury and there are many defects in current targeted delivery of miRNAs for the treatment of ferroptosis. We herein report a unique hydrogel (Gel) that can be triggered by a near-infrared-II (NIR-II) light with deep tissue penetration and biocompatible maximum permissible exposure (MPE) value for in situ treatment after I/R. The mir-196c-3p mimic (mimics) and photothermal nanoparticles (BTN) were co-encapsulated in an injectable Gel (mimics + Gel/BTN) with NIR-II light-triggered release. Using 1064 nm light irradiation, local microenvironment photothermal-triggered on-demand noninvasive controllable delivery of miRNA was achieved, aiming to inhibit I/R-induced ferroptosis. Consequently, declined ferroptosis in cardiomyocytes and improved cardiac function, survival rate in rats was achieved through the controlled release of Gel/BTN mimics in I/R model to simultaneously inhibit ferroptosis hub genes NOX4, P53, and LOX expression.

Protective role of serpina3c as a novel thrombin inhibitor against atherosclerosis in mice.

Abnormal vascular smooth muscle cell (VSMC) proliferation is a critical step in the development of atherosclerosis. Serpina3c is a serine protease inhibitor (serpin) that plays a key role in metabolic diseases. The present study aimed to investigate the role of serpina3c in atherosclerosis and regulation of VSMC proliferation and possible mechanisms. Serpina3c is down-regulated during high-fat diet (HFD)-induced atherosclerosis. An Apoe-/-/serpina3c-/--double-knockout mouse model was used to determine the role of serpina3c in atherosclerosis after HFD for 12 weeks. Compared with Apoe-/- mice, the Apoe-/-/serpina3c-/- mice developed more severe atherosclerosis, and the number of VSMCs and macrophages in aortic plaques was significantly increased. The present study revealed serpina3c as a novel thrombin inhibitor that suppressed thrombin activity. In circulating plasma, thrombin activity was high in the Apoe-/-/serpina3c-/- mice, compared with Apoe-/- mice. Immunofluorescence staining showed thrombin and serpina3c colocalization in the liver and aortic cusp. In addition, inhibition of thrombin by dabigatran in serpina3c-/- mice reduced neointima lesion formation due to partial carotid artery ligation. Moreover, an in vitro study confirmed that thrombin activity was also decreased by serpina3c protein, supernatant and cell lysate that overexpressed serpina3c. The results of experiments showed that serpina3c negatively regulated VSMC proliferation in culture. The possible mechanism may involve serpina3c inhibition of ERK1/2 and JNK signaling in thrombin/PAR-1 system-mediated VSMC proliferation. Our results highlight a protective role for serpina3c as a novel thrombin inhibitor in the development of atherosclerosis, with serpina3c conferring protection through the thrombin/PAR-1 system to negatively regulate VSMC proliferation through ERK1/2 and JNK signaling.

Erythropoietin Attenuates Cardiac Dysfunction in Rats by Inhibiting Endoplasmic Reticulum Stress-Induced Diabetic Cardiomyopathy.

PURPOSE: Enhanced endoplasmic reticulum (ER) stress and down-regulated SERCA2a expression play crucial roles in diabetes. We aimed to verify whether erythropoietin (EPO) attenuates cardiac dysfunction by suppressing ER stress in diabetic rats. METHODS: Forty male SD rats were randomly divided into four groups: control, EPO-treated control, vehicle-treated diabetic, and EPO-treated diabetic groups. The animals in the EPO-treated control and diabetic groups were administered recombinant human EPO (1000 U/kg body weight) once per week for 12 weeks. RT-PCR and Western blotting assays were performed to detect the expression of 78-kDa glucose-regulated protein precursor (GRP78) and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA2a). We cultured neonatal rat cardiomyocytes and investigated the protective effects of EPO against high glucose (HG)-induced apoptosis. Intracellular calcium levels were measured through confocal microscopy. RESULTS: We observed increased myocardial GRP78 expression and decreased myocardial SERCA2a expression in diabetic rats. EPO prevented the changes in GRP78, SERCA2a expression and cardiac dysfunction in diabetic rats. The levels of GRP78 protein were significantly reduced in EPO-treated diabetic rats compared with vehicle-treated diabetic rats (GRP78 protein 0.09 ± 0.03 vs. 0.54 ± 0.04, P < 0.01). The levels of the SERCA2a proteins were significantly increased in EPO-treated diabetic rats compared with vehicle-treated diabetic rats (SERCA2a protein 0.60 ± 0.05 vs. 0.13 ± 0.04, P < 0.01). A reduction in apoptosis was observed in the cardiomyocytes treated with 20 U/mL EPO compared with the cardiomyocytes cultured under HG conditions (apoptosis rate 18.9 ± 1.94 vs. 37.9 ± 1.59%, P < 0.01). CONCLUSIONS: This study demonstrates that EPO treatment improved the parameters of cardiac function following HG-induced injury by suppressing ER stress and inducing SERCA2a expression.

[Impact and related mechanisms of stromal cell-derived factor-1α on serum deprivation-induced cardiac stem cells apoptosis].

OBJECTIVE: To explore the impact and related mechanisms of stromal cell-derived factor-1α (SDF-1α) on serum deprivation-induced apoptosis of cardiac stem cells (CSCs). METHODS: CSCs were isolated from adult mouse heart tissue and cultured in vitro. Obtained cells were purified using magnetic-activated cell sorting (MACS) with c-kit magnetic beads. C-kit(+)CSCs were divided into five groups: normal control group, serum deprivation group, serum deprivation+SDF-1α group, serum deprivation+SDF-1α+AMD3100 group, serum deprivation+SDF-1α+LY294002 group. Cell apoptosis was assessed using the DeadEnd Colorimetric TUNEL System and flow cytometry analyses with an Annexin V-FITC Apoptosis Detection Kit. The viability of CSCs was assessed by CCK-8. The protein expression of Bcl-2 and phosphorylated Akt were detected by Western blot. The caspase-3 activity was determined using caspase-3 Colorimetric Assay Kit. RESULTS: After magnetic separation, more than 85% of cardiosphere derived cells were positive for c-kit expression. Compared with the normal control group, the apoptosis rate of serum deprivation group was significantly increased[(27.03 ± 0.80)% vs. (1.51 ± 0.54)%, P < 0.01], which could be significantly reduced by SDF-1α in a concentration dependent manner and peak effect was seen with 100 ng/ml SDF-1α[(10.67 ± 1.06)% vs. (27.03 ± 0.80)%, P < 0.01]. The expressions of p-Akt and Bcl-2 were significantly increased and the activity of caspase-3 was significantly decreased in serum deprivation+SDF-1α group compared to serum deprivation group (P < 0.01). Further more, the expression of p-Akt and Bcl-2 were significantly decreased and the activity of caspase-3 was increased in both serum deprivation+SDF-1α+AMD3100 group and serum deprivation+SDF-1α+LY294002 group compared to serum deprivation+SDF-1α group (P < 0.01). CONCLUSIONS: SDF-1α reduces serum deprivation induced CSCs apoptosis via modulating PI3K/Akt signaling pathway.

Kallistatin Improves High-Fat-Induced Insulin Resistance via Epididymal Adipose Tissue-Derived Exosomes.

Objective: Studies have found that high expression of human Kallistatin (HKS) in adipose tissue can improve obesity and its associated comorbidities, but the underlying mechanism of specific regulation is unclear. Methods: An obesity model was built by injecting 8-week-old C57BL/6 mice (n = 6 mice per group) with Ad.Null and Ad.HKS adenovirus into epididymal adipose tissue and fed with a high-fat diet (HFD). Insulin resistance-related proteins, AKT and IRS1, were detected in the liver, subcutaneous fat, and skeletal muscle by western blotting after one month of HFD. Epididymal adipose tissue was isolated after 24 h for culture, and exosomes were extracted by differential centrifugation. Enzyme-linked immunosorbent assay detected the expression of HKS protein in serum and exosomes. To examine the role of exosomes in AML12 insulin resistance, we used epididymal adipose tissue-derived exosomes or transfected Ad.HKS into mature 3T3L1-derived exosomes to interfere with palmitic acid (PA)-induced mouse AML12 insulin resistance model. GW4869 was used to inhibit exosome biogenesis and release. Results: Our results showed that HFD-induced mice with high expression of HKS in epididymal adipose tissue had slower weight gain, lower serum triglycerides, reduced free fatty acids, and improved liver insulin resistance compared with the Ad.Null group. We also demonstrated that HKS was enriched in epididymal adipose tissue-derived exosomes and released through the exosome pathway. In PA-induced AML12 cells, insulin resistance was alleviated after incubation of the HKS-related exosome; this effect was reversed with GW4869. Conclusion: High expression of HKS in epididymal adipose tissue could lead to its exocrine secretion in the form of exosomes and improve liver insulin resistance by promoting the phosphorylation of AKT. Production of high HKS vesicles might be a possible way to alleviate insulin resistance associated with obesity.

Visceral adipose tissue-directed human kallistatin gene therapy improves adipose tissue remodeling and metabolic health in obese mice.

OBJECTIVE: Adipose tissue remodeling is a dynamic process that is pathologically expedited in the obese state and is closely related to obesity-associated disease progression. This study aimed to explore the effects of human kallistatin (HKS) on adipose tissue remodeling and obesity-related metabolic disorders in mice fed with a high-fat diet (HFD). METHODS: Adenovirus-mediated HKS cDNA (Ad.HKS) and a blank adenovirus (Ad.Null) were constructed and injected into the epididymal white adipose tissue (eWAT) of 8-weeks-old male C57B/L mice. The mice were fed normal or HFD for 28 days. The body weight and circulating lipids levels were assessed. Intraperitoneal glucose tolerance test (IGTT) and insulin tolerance test (ITT) were also performed. Oil-red O staining was used to assess the extent of lipid deposition in the liver. Immunohistochemistry and HE staining were used to measure HKS expression, adipose tissue morphology, and macrophage infiltration. Western blot and qRT-PCR were used to evaluate the expression of adipose function-related factors. RESULTS: At the end of the experiment, the expression of HKS in the serum and eWAT of the Ad.HKS group was higher than in the Ad.Null group. Furthermore, Ad.HKS mice had lower body weight and decreased serum and liver lipid levels after four weeks of HFD feeding. IGTT and ITT showed that HKS treatment maintained balanced glucose homeostasis. Additionally, inguinal white adipose tissue (iWAT) and eWAT in Ad.HKS mice had a higher number of smaller-size adipocytes and had less macrophage infiltration than Ad.Null group. HKS significantly increased the mRNA levels of adiponectin, vaspin, and eNOS. In contrast, HKS decreased RBP4 and TNFα levels in the adipose tissues. Western blot results showed that local injection of HKS significantly upregulated the protein expressions of SIRT1, p-AMPK, IRS1, p-AKT, and GLUT4 in eWAT. CONCLUSIONS: HKS injection in eWAT improves HFD-induced adipose tissue remodeling and function, thus significantly improving weight gain and dysregulation of glucose and lipid homeostasis in mice.

Identification of major hub genes involved in high-fat diet-induced obese visceral adipose tissue based on bioinformatics approach.

High-fat diet (HFD) can cause obesity, inducing dysregulation of the visceral adipose tissue (VAT). This study aimed to explore potential biological pathways and hub genes involved in obese VAT, and for that, bioinformatic analysis of multiple datasets was performed. The expression profiles (GSE30247, GSE167311 and GSE79434) were downloaded from Gene Expression Omnibus. Overlapping differentially expressed genes (ODEGs) between normal diet and HFD groups in GSE30247 and GSE167311 were selected to run protein-protein interaction network, GO and KEGG analysis. The hub genes in ODEGs were screened by Cytoscape software and further verified in GSE79434 and obese mouse model. A total of 747 ODEGs (599 up-regulated and 148 down-regulated) were screened, and the GO and KEGG analysis showed that the up-regulated ODEGs were significantly enriched in inflammatory response and extracellular matrix receptor interaction pathways. On the other hand, the down-regulated ODEGs were involved in metabolic pathways; however, there were no significant KEGG pathways. Furthermore, six hub genes, Mki67, Rac2, Itgb2, Emr1, Tyrobp and Csf1r were acquired. These pathways and genes were verified in GSE79434 and VAT of obese mice. This study revealed that HFD induced VAT expansion, inflammation and fibrosis, and the hub genes could be used as therapeutic biomarkers in obesity.

Erythropoietin attenuates cardiac dysfunction by increasing myocardial angiogenesis and inhibiting interstitial fibrosis in diabetic rats.

BACKGROUND: Recent studies revealed that erythropoietin (EPO) has tissue-protective effects in the heart by increasing vascular endothelial growth factor (VEGF) expression and attenuating myocardial fibrosis in ischemia models. In this study, we investigated the effect of EPO on ventricular remodeling and blood vessel growth in diabetic rats. METHODS: Male SD rats were randomly divided into 3 groups: control rats, streptozotocin (STZ)-induced diabetic rats, and diabetic rats treated with 1000 U/kg EPO by subcutaneous injection once per week. Twelve weeks later, echocardiography was conducted, and blood samples were collected for counting of peripheral blood endothelial progenitor cells (EPCs). Myocardial tissues were collected, quantitative real-time PCR (RT-PCR) was used to detect the mRNA expression of VEGF and EPO-receptor (EPOR), and Western blotting was used to detect the protein expression of VEGF and EPOR. VEGF, EPOR, transforming growth factor beta (TGF-ß), and CD31 levels in the myocardium were determined by immunohistochemistry. To detect cardiac hypertrophy, immunohistochemistry of collagen type I, collagen type III, and Picrosirius Red staining were performed, and cardiomyocyte cross-sectional area was measured. RESULTS: After 12 weeks STZ injection, blood glucose increased significantly and remained consistently elevated. EPO treatment significantly improved cardiac contractility and reduced diastolic dysfunction. Rats receiving the EPO injection showed a significant increase in circulating EPCs (27.85 ± 3.43%, P < 0.01) compared with diabetic untreated animals. EPO injection significantly increased capillary density as well as EPOR and VEGF expression in left ventricular myocardial tissue from diabetic rats. Moreover, EPO inhibited interstitial collagen deposition and reduced TGF-ß expression. CONCLUSIONS: Treatment with EPO protects cardiac tissue in diabetic animals by increasing VEGF and EPOR expression levels, leading to improved revascularization and the inhibition of cardiac fibrosis.

Kallistatin/Serpina3c inhibits cardiac fibrosis after myocardial infarction by regulating glycolysis via Nr4a1 activation.

BACKGROUND: Fibrotic remodeling is an essential aspect of heart failure. Human kallistatin (KS, mouse Serpina3c homologs) inhibits fibrosis after myocardial infarction (MI) but the specific underlying mechanism is unknown. METHODS: A total of 40 heart failure patients (HFPs) were enrolled and their plasma KS was measured using ELISA. Serpina3c-/- and C57BL/6 mice were used to construct the MI model. TGF-ß1 or a hypoxic condition was established to interfere with the functioning of cardiac fibroblasts (CFs). RNA-seq was performed to assess the effect of Serpina3c on the transcriptome. FINDINGS: The levels of KS were used as a predictor of readmission among the HFPs. Serpina3c expression decreased in MI hearts and CFs. Serpina3c-/- led to the aggravation of MI fibrosis, and increased the proliferation of CFs. The overexpression of Serpina3c in CFs had the opposite effect. Glycolysis-related genes were significantly increased in Serpina3c-/- group by RNA-seq. Enolase (ENO1), which is a key enzyme in glycolysis, increased most significantly. Inhibition of ENO1 could antagonize the promotion of Serpina3c-/- on the proliferation of CFs. Co-IP was performed to verify the interaction between Serpina3c and Nr4a1. Serpina3c-/- inhibited the acetylation of Nr4a1 and increased the degradation of Nr4a1. Activation of Nr4a1 could negatively regulate the expression of ENO1 and inhibited the proliferation of Serpina3c-/- CFs in Serpina3c-/- MI mice. INTERPRETATION: Serpina3c inhibits the transcriptional activation of ENO1 by regulating the acetylation of Nr4a1, thereby reducing the fibrosis after MI by inhibiting glycolysis. Serpina3c is a potential target for prevention and treatment of heart failure after MI.

Role of ferroptosis in the process of diabetes-induced endothelial dysfunction.

BACKGROUND: Endothelial dysfunction, a hallmark of diabetes, is a critical and initiating contributor to the pathogenesis of diabetic cardiovascular complications. However, the underlying mechanisms are still not fully understood. Ferroptosis is a newly defined regulated cell death driven by cellular metabolism and iron-dependent lipid peroxidation. Although the involvement of ferroptosis in disease pathogenesis has been shown in cancers and degenerative diseases, the participation of ferroptosis in the pathogenesis of diabetic endothelial dysfunction remains unclear. AIM: To examine the role of ferroptosis in diabetes-induced endothelial dysfunction and the underlying mechanisms. METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with high glucose (HG), interleukin-1ß (IL-1ß), and ferroptosis inhibitor, and then the cell viability, reactive oxygen species (ROS), and ferroptosis-related marker protein were tested. To further determine whether the p53-xCT (the substrate-specific subunit of system Xc-)-glutathione (GSH) axis is involved in HG and IL-1ß induced ferroptosis, HUVECs were transiently transfected with p53 small interfering ribonucleic acid or NC small interfering ribonucleic acid and then treated with HG and IL-1ß. Cell viability, ROS, and ferroptosis-related marker protein were then assessed. In addition, we detected the xCT and p53 expression in the aorta of db/db mice. RESULTS: It was found that HG and IL-1ß induced ferroptosis in HUVECs, as evidenced by the protective effect of the ferroptosis inhibitors, Deferoxamine and ferrostatin-1, resulting in increased lipid ROS and decreased cell viability. Mechanistically, activation of the p53-xCT-GSH axis induced by HG and IL-1ß enhanced ferroptosis in HUVECs. In addition, a decrease in xCT and the presence of de-endothelialized areas were observed in the aortic endothelium of db/db mice. CONCLUSION: Ferroptosis is involved in endothelial dysfunction and p53-xCT-GSH axis activation plays a crucial role in endothelial cell ferroptosis and endothelial dysfunction.

[Value of in vivo monitoring of abdominal aortic atherosclerosis by high field magnetic resonance imaging in apoE-/- mice fed a high fat diet or infused with angiotensin II].

OBJECTIVE: to explore the value of in vivo dynamic monitoring of abdominal aortic atherosclerosis (AS) by high field magnetic resonance (MR) imaging (MRI) in apoE-/- mice fed a high fat diet or infused with angiotensin. METHODS: high fat diet or angiotensin II infusion was applied to apoE-/- mice for establishment of abdominal aortic atherosclerosis model. Abdominal aorta MRI was performed at 3 time points (baseline, 3 and 6 months) in 13 high fat diet fed apoE-/- mice aged 10-12 months and 3 wild-type control mice; 10 apoE-/- mice aged 6 months were infused with angiotensin II (1000 or 500 ng × kg(-1)× min(-1), n = 5 each) or saline for 14 d through Osmotic minipump. The abdominal aortic artery MRI was performed at baseline and 14 d after infusion. Black blood sequences of FLASH T1 weighted images and Proton density weighted-T2 weighted dual echo images were obtained. At each observation time post MRI, mice (n = 3, 5 and 5 for high fat diet group and n = 5 and 5 for angiotensin II infusion group) were sacrificed for pathological examination of the abdominal artery. RESULTS: (1) the abdominal aorta atherosclerosis was identified in both high fat diet and angiotensin II treated apoE-/- mice but in WT controls. Lesion progression was documented in high fat diet fed apoE-/- mice characterized by significantly increased vessel wall (a marker of atherosclerotic burden, F = 29.94, P < 0.05) and gradually increased plaque signal in PDW and T2W images. Results derived from MRI corresponded histopathology findings in high fat diet fed apoE-/- mice (correlative coefficient = 0.84, 0.95, 0.90, P < 0.05, respectively). Both MRI and histology showed increased lipid composition and decreased fibrotic composition in these mice. (2) The vessel wall area increased significantly [(1.21 ± 0.21) mm(2) vs. (2.65 ± 0.48) mm(2), P < 0.05] and the abdominal aortic dissection aneurysms was identified in apoE-/- mice infused with high angiotensin II. The vessel wall area also increased [(0.85 ± 0.11) mm(2) vs. (1.01 ± 0.17) mm(2), P < 0.05] in low angiotensin II infused apoE-/- mice and the coefficient between MR and histopathology is 0.934. CONCLUSION: abdominal aortic unstable plaque model could be established by both high fat diet and angiotensin II infusion in apoE mice, angiotensin II infusion can transiently accelerate the progression of AS and can induce abdominal aortic dissection. Serial MR black blood sequences could demonstrate the development and progression of atherosclerosis in mouse abdominal aorta with excellent agreement to histopathology finding in terms of atherosclerotic burden and plaque composition. Thus, MRI appears to be a useful tool for in vivo AS plaque dynamic monitoring in mice.

Serpina3c protects against high-fat diet-induced pancreatic dysfunction through the JNK-related pathway.

BACKGROUND: Serpina3 is a member of the serine protease inhibitor family and is involved in the inflammatory response. In this study, we investigated the effect of Serpina3c on pancreatic function in hypercholesterolemic mice. METHODS: To investigate the role of Serpina3c in hyperlipidaemia, Serpina3c knockout mice were bred with Apoe-knockout mice (on a C57BL/6 background) to generate heterozygous Serpina3c-Apoe double knockout (Serpina3c+/-/Apoe+/-) mice and were then bred to obtain homozygotes. C57BL/6, Serpina3c-/-, Apoe-/-, and Apoe-/-Serpina3c-/- mice were fed normal chow, and Apoe-/- and Apoe-/-Serpina3c-/- mice were fed a high-fat diet (HFD). After feeding for 3 months, the mice were monitored for body weight, blood glucose, glucose tolerance, and insulin tolerance test (ITT). ELISA and immunohistochemistry were used to detect insulin levels and glucagon expression. Immunohistochemical staining for macrophages in the pancreas was also performed. Western blot analysis was performed on pancreatic tissues to detect the protein levels of insulin-associated molecules, the metalloproteinase MMP2, the tissue inhibitor TIMP2 and components of the JNK-related pathway. RESULTS: Blood glucose levels, glucose tolerance, and ITT were not significantly different among the groups. Serpina3c knockout resulted in blood lipid abnormalities in mice under HFD conditions. Insulin secretion was decreased in Apoe-/-Serpina3c-/- mice compared with Apoe-/- mice under normal chow conditions. In addition, Apoe-/-Serpina3c-/- mice exhibited increased insulin and glucagon secretion and expression after three months of HFD feeding, but insulin secretion was decreased in Apoe-/-Serpina3c-/- mice compared with Apoe-/- mice after the fifth month of HFD feeding. Serpina3c knockout increased MMP2 protein levels, whereas TIMP2 levels in the pancreas were decreased. Furthermore, Serpina3c knockout significantly upregulated the number of macrophages in the pancreas under HFD conditions. The JNK/AKT/FOXO1/PDX-1 axis was found to be involved in Serpina3c-regulated insulin secretion. CONCLUSION: These novel findings show that Serpina3c could play a protective role in insulin secretion partly through the JNK-related pathway under HFD conditions.

[Preliminary exploration of transcription factor Nkx2.5 mutations and congenital heart diseases].

OBJECTIVE: To explore the association between the gene mutation of transcription factor Nkx2.5 and Chinese patients with congenital heart disease (CHD). METHODS: Polymerase chain reaction (PCR) and DNA sequencing were used to check 99 CHD patients and 90 normal control subjects from the Zhong Da Hospital of Southeast University. After amplifying the exons 1 of the Nkx2.5 gene by PCR, we purified the PCR products and conducted the sequencing reaction, analyzed the mutation screening of the exon 1 of the Nkx2.5, investigated whether or not the Nkx2.5 is related with the CHD in Chinese population. RESULTS: A mutation (A239G) in the exon 1 of the Nkx2.5 was identified in 3 of 90 normal control subjects and 12 of 99 CHD patients, including 3 of 24 with VSD, 7 of 35 with ASD, 1 of 13 with PS and 1 of 21 with PDA. CONCLUSION: There are some associations between the Nkx2.5 gene mutation and occurrence of congenital heart disease in Chinese people.

[Effects of autologous mesenchymal stem cells transfected with heme oxygenase-1 gene transplantation on ischemic Swine hearts].

OBJECTIVE: To observe the effect of intracoronary transfer of autologous HO-1 overexpressed MSCs in porcine model of myocardial ischemia (1 h)/reperfusion. METHODS: Apoptosis was assayed and cytokine concentrations in supernatant were measured in cells exposed to hypoxia-reoxygen in vitro. In vivo, Chinese male mini-pigs were allocated to the following treatment groups: control group (saline), MSCs group (MSCs), MSCs transfected with pcDNA3.1-nHO-1 (HO-1-MSCs). 1 x 10(7) of autologous stem cells or identical volume of saline was injected intracoronary into porcine hearts 1 h after ischemia. MRI assay and postmortem analysis were assessed 3 months after stem cell transplantation. RESULTS: In vitro, cell apoptosis rate post hypoxia-reoxygen was significantly reduced in HO-1-MSCs group (30.30% +/- 7.64%) compared with that in MSCs group (56.93% +/- 4.68%, P < 0.001) and LacZ-MSCs group (55.88% +/- 4.38%, P < 0.001), VEGF was also significantly upregulated in HO-1-MSCs group [(768.44 +/- 78.38) pg/ml] compared with that in MSCs group [(555.27 +/- 67.67) pg/ml, P < 0.001] and LacZ-MSCs group [(522.97 +/- 71.45) pg/ml, P < 0.001]. In vivo, cardiac function was significantly improved in both MSCs transplantation groups compared to saline group (all P < 0.05 vs.saline) and the left ventricular ejection fraction was significantly higher in HO-1-MSCs group compared with that in MSCs group at 3 months after transplantation (53.50% +/- 2.09% vs. 49.54% +/- 2.74%, P = 0.017), capillary density in the peri-infarct area was also significantly higher in HO-1-MSC group than that in MSCs group [(14.59 +/- 2.39)/HPF vs. (11.78 +/- 2.48)/HPF, P = 0.033]. CONCLUSIONS: Efficacy of HO-1 overexpressed MSCs on improving cardiac function and promoting angiogenesis was greater than those by MSCs in this porcine ischemia/reperfusion model.

Tissue kallikrein protects against pressure overload-induced cardiac hypertrophy through kinin B2 receptor and glycogen synthase kinase-3beta activation.

OBJECTIVE: We assessed the role of glycogen synthase kinase-3beta (GSK-3beta) and kinin B2 receptor in mediating tissue kallikrein's protective effects against cardiac hypertrophy. METHODS: We investigated the effect and mechanisms of tissue kallikrein using hypertrophic animal models of rats as well as mice deficient in kinin B1 or B2 receptor after aortic constriction (AC). RESULTS: Intramyocardial delivery of adenovirus containing the human tissue kallikrein gene resulted in expression of recombinant kallikrein in rat myocardium. Kallikrein gene delivery improved cardiac function and reduced heart weight/body weight ratio and cardiomyocyte size without affecting mean arterial pressure 28 days after AC. Icatibant and adenovirus carrying a catalytically inactive GSK-3beta mutant (Ad.GSK-3beta-KM) abolished kallikrein's effects. Kallikrein treatment increased cardiac nitric oxide (NO) levels and reduced NAD(P)H oxidase activity and superoxide production. Furthermore, kallikrein reduced the phosphorylation of apoptosis signal-regulating kinase1, mitogen-activated protein kinases (MAPKs), Akt, GSK-3beta, and cAMP-response element binding (CREB) protein, and decreased nuclear factor-kappaB (NF-kappaB) activation in the myocardium. Ad.GSK-3beta-KM abrogated kallikrein's actions on GSK-3beta and CREB phosphorylation and NF-kappaB activation, whereas icatibant blocked all kallikrein's effects. The protective role of kinin B2 receptor in cardiac hypertrophy was further confirmed in kinin receptor knockout mice as heart weight/body weight ratio and cardiomyocyte size increased significantly in kinin B2 receptor knockout mice after AC compared to wild type and B1 receptor knockout mice. CONCLUSIONS: These findings indicate that tissue kallikrein, through kinin B2 receptor and GSK-3beta signaling, protects against pressure overload-induced cardiomyocyte hypertrophy by increased NO formation and oxidative stress-induced Akt-GSK-3beta-mediated signaling events, MAPK and NF-kappaB activation.

Tissue kallikrein and kinin infusion rescues failing myocardium after myocardial infarction.

BACKGROUND: Tissue kallikrein is a serine proteinase that generates the vasoactive kinin peptide, which produces vasodilatory, angiogenic, and antiapoptotic effects. In this study, we investigated the effect of a stable supply of kallikrein and kinin on ventricular remodeling and blood vessel growth in rats after myocardial infarction. METHODS AND RESULTS: At 1 week after coronary artery ligation, tissue kallikrein or kinin was infused through a minipump for 4 weeks. At 5 weeks after myocardial infarction, kallikrein and kinin infusion significantly improved cardiac contractility and reduced diastolic dysfunction without affecting systolic blood pressure. Kallikrein and kinin infusion significantly increased capillary density in the noninfarcted region. Kallikrein and kinin infusion also reduced heart weight/body weight ratio, cardiomyocyte size, and atrial natriuretic peptide and brain natriuretic peptide expression in the noninfarcted area. Moreover, kallikrein and kinin infusion inhibited interstitial collagen deposition, collagen fraction volume, and collagen I and collagen III mRNA levels, transforming growth factor (TGF)-beta1 and plasminogen activator inhibitor-1 expression, and Smad2 phosphorylation. The effects of kallikrein and kinin on cardiac remodeling were associated with increased nitric oxide levels and reduced NADPH oxidase expression and activity, superoxide formation, and malondialdehyde levels. Furthermore, in cultured cardiac fibroblasts, kinin inhibited angiotensin II-stimulated TGF-beta1 production, and the effect was blocked by icatibant. CONCLUSION: These results indicate that a subdepressor dose of kallikrein or kinin can restore impaired cardiac function in rats with postinfarction heart failure by inhibiting hypertrophy and fibrosis and promoting angiogenesis through increased nitric oxide formation and suppression of oxidative stress and TGF-beta1 expression.

Tissue kallikrein infusion prevents cardiomyocyte apoptosis, inflammation and ventricular remodeling after myocardial infarction.

We investigated the effect of tissue kallikrein infusion on cardiac protection at acute and sub-acute phases after myocardial infarction (MI). Immediately after MI, rats were infused with purified tissue kallikrein, with or without icatibant (a kinin B2 receptor antagonist). Intramyocardial injection of kallikrein reduced myocardial infarct size and inhibited cardiomyocyte apoptosis at 1 day after MI associated with increased nitric oxide levels, Akt and glycogen synthase kinase-3beta phosphorylation and decreased caspase-3 activation. Kallikrein infusion for 7 days improved cardiac function, normalized left ventricular wall thickness and decreased monocyte/macrophage infiltration in the infarct heart. Kallikrein treatment reduced NADH oxidase expression and activity, superoxide formation and malondialdehyde levels, and reduced MAPK and Ikappa-Balpha phosphorylation, NF-kappaB activation and MCP-1 and VCAM-1 expression. Kallikrein's effects were all blocked by icatibant. These results indicate that kallikrein through kinin B2 receptor activation prevents apoptosis, inflammation and ventricular remodeling by increased nitric oxide formation and suppression of oxidative stress-mediated signaling pathways.

Novel role of kallistatin in protection against myocardial ischemia-reperfusion injury by preventing apoptosis and inflammation.

Kallistatin is a serine proteinase inhibitor that has been shown to reduce joint swelling and to inhibit inflammation in a rat model of arthritis. In this study, we investigated the effect and mechanisms of kallistatin on cardiac function after myocardial ischemia-reperfusion (I/R) injury. The human kallistatin gene in an adenoviral vector was delivered locally into rat heart 4 days before 30-min ischemia followed by 24-hr reperfusion. Kallistatin gene transfer significantly reduced myocardial infarct size and left ventricle end-diastolic pressure and improved cardiac contractility. Kallistatin significantly reduced I/R-induced cardiomyocyte apoptosis as identified by TUNEL and Hoechst staining, DNA laddering, cell viability, and caspase-3 activity in ischemic myocardium and in primary cultured cardiomyocytes. Kallistatin also reduced intramyocardial monocyte/macrophage and neutrophil accumulation in conjunction with decreased expression of monocyte chemoattractant protein-1, tumor necrosis factor-alpha, and intercellular adhesion molecule-1. Kallistatin delivery promoted cardiac endothelial nitric oxide synthase activation and increased nitric oxide (NO) formation, but inhibited NADH oxidase activity, p22phox expression, and superoxide production. Moreover, kallistatin reduced the phosphorylation of apoptosis signal-regulating kinase-1 and mitogen-activated protein kinases (MAPKs), but increased Akt and glycogen synthase kinase-3beta phosphorylation. The effects of kallistatin on cardiac function, oxidative stress, and these signal transduction events were all blocked by Nomega-nitro-L-argi-nine methyl ester. These results indicate a novel role of kallistatin in cardiac protection after I/R injury through increased NO formation and Akt-glycogen synthase kinase-3beta signaling and suppression of oxidative stress and MAPK activation.

Kallikrein protects against ischemic stroke by inhibiting apoptosis and inflammation and promoting angiogenesis and neurogenesis.

Stroke-induced neurological deficits and mortality are often associated with timing of treatment after the onset of stroke. We showed that local delivery of the human tissue kallikrein gene into rat brain immediately after middle cerebral artery occlusion (MCAO) exerts neuroprotection. In this study, we investigated the effect of systemic delivery of the kallikrein gene 8 hr after MCAO. Expression of recombinant human tissue kallikrein after gene transfer was identified in the ischemic brain region and blood vessels. Intravenous injection of adenovirus encoding the kallikrein gene significantly reduced neurological deficit scores 2 and 7 days after gene transfer. Kallikrein gene transfer also reduced ischemia-reperfusion (I/R)-induced cerebral infarction and promoted the survival and migration of glial cells from penumbra to the ischemic core from 3 to 14 days after gene delivery. Kallikrein reduced I/R-induced apoptosis of neuronal cells and inhibited inflammatory cell accumulation in the ischemic brain. These effects were blocked by the kinin B2 receptor antagonist icatibant. In addition, kallikrein enhanced angiogenesis and promoted neurogenesis after I/R and the stimulatory effect of kinin on neuronal cell proliferation was confirmed in primary cultured neuronal cells. The protective effects of kallikrein, through the kinin B2 receptor, were accompanied by increased cerebral nitric oxide and Bcl-2 levels, Akt phosphorylation, and reduced NAD(P)H oxidase activity, superoxide production, Bax levels, and caspase-3 activity. These results indicate that delayed systemic administration of the kallikrein gene after onset of stroke protects against ischemic brain injury by inhibiting apoptosis and inflammation and by promoting angiogenesis and neurogenesis.