Parathyroid Hormone-Related Protein (1-40) Enhances Calcium Uptake in Rat Enterocytes Through PTHR1 Receptor and Protein Kinase Cα/ß Signaling.

BACKGROUND/AIMS: Parathyroid hormone-related protein (PTHrP) is implicated in regulating calcium homeostasis in vertebrates, including sea bream, chick, and mammals. However, the molecular mechanism underlying the function of PTHrP in regulating calcium transport is still not fully investigated. This study aimed to investigate the effect of PTHrP on the calcium uptake and its underlying molecular mechanism in rat enterocytes. METHODS: The rat intestinal epithelial cell line (IEC-6) was used. Calcium uptake was determined by using the fluo-4 acetoxymethyl ester fluorescence method. The expression levels of RNAs and proteins was assessed by RT-PCR and Western-blot, respectively. RESULTS: PTHrP (1-40) induced rapid calcium uptake in enterocytes in a dose-dependent manner. PTHrP (1-40) up-regulated parathyroid hormone 1 receptor (PTHR1) protein but not 1,25D3-MARRS receptor. Pre-treatment of anti- PTHR1 antibody abolished the PTHrP (1-40)-induced calcium uptake. PTHrP (1-40) significantly up-regulated four transcellular calcium transporter proteins, potential vanilloid member 6 (TRPV6), calbindin-D9k (CaBP-D9k), sodium-calcium exchanger 1 (NCX1) and plasma membrane calcium ATPase 1 (PMCA1), in a dose- and time-dependent manner. Pre-treatment with TRPV6 or CaBP-D9k antibodies or knockout of rat TRPV6 or CaBP-D9k markedly inhibited PTHrP (1-40)-induced calcium uptake, whereas inhibition of NCX or PMCA1 by antibodies or inhibitors had no effect on PTHrP(1-40)-induced calcium uptake. Furthermore, PTHrP (1-40) treatment up-regulated protein levels of protein kinase C (PKC α/ß) and protein kinase A (PKA). Pretreatment of PKC α/ß inhibitor (but not PKA inhibitor) inhibited PTHrP (1-40)-induced calcium uptake. CONCLUSION: PTHrP (1-40) stimulates calcium uptake via PTHR1 receptor and PKC α/ß signaling pathway in rat enterocytes, and calcium transporters TRPV6 and CaBP-D9k are necessary for this stimulatory effect.

Overexpression of ß-actin is closely associated with metastasis of gastric cancer.

BACKGROUND/AIMS: ß-actin is known to be involved in motility of cancer cells. However, the association between ß-actin expression and metastasis of gastric cancer remains unclear. METHODOLOGY: We enrolled 40 gastric cancer patients who underwent gastrectomy and evaluated the expression of ß-actin in gastric cancer tissues and the corresponding normal mucosa by the analysis of Western blotting. To further study the function of ß-actin in cancer cell migration, wound healing assay was performed in SGC7901 transfected with ß-actin siRNA. RESULTS: The level of ß-actin was significantly higher in gastric cancer tissues than in the corresponding normal mucosa. The correlation between ß-actin expression and the local lymph node metastasis was statistically significant, which demonstrated that overexpression of ß-actin might contribute to the local lymph node metastasis of gastric cancer. Interference of ß-actin expression could inhibit migration of SGC7901 cells. CONCLUSIONS: ß-actin, the most conservative and dynamic protein, is overexpressed in gastric cancer tissues and may play a crucial role in metastasis of gastric cancer.

Spironolactone lowers portal hypertension by inhibiting liver fibrosis, ROCK-2 activity and activating NO/PKG pathway in the bile-duct-ligated rat.

OBJECTIVE: Aldosterone, one of the main peptides in renin angiotensin aldosterone system (RAAS), has been suggested to mediate liver fibrosis and portal hypertension. Spironolactone, an aldosterone antagonist, has beneficial effect on hyperdynamic circulation in clinical practice. However, the mechanisms remain unclear. The present study aimed to investigate the role of spionolactone on liver cirrhosis and portal hypertension. METHODS: Liver cirrhosis was induced by bile duct ligation (BDL). Spironolactone was administered orally (20 mg/kg/d) after bile duct ligation was performed. Liver fibrosis was assessed by histology, Masson's trichrome staining, and the measurement of hydroxyproline and type I collagen content. The activation of HSC was determined by analysis of alpha smooth muscle actin (α-SMA) expression. Protein expressions and protein phosphorylation were determined by immunohistochemical staining and Western blot analysis, Messenger RNA levels by quantitative real time polymerase chain reaction (Q-PCR). Portal pressure and intrahepatic resistance were examined in vivo. RESULTS: Treatment with spironolactone significantly lowered portal pressure. This was associated with attenuation of liver fibrosis, intrahepatic resistance and inhibition of HSC activation. In BDL rat liver, spironolactone suppressed up-regulation of proinflammatory cytokines (TNFα and IL-6). Additionally, spironolactone significantly decreased ROCK-2 activity without affecting expression of RhoA and Ras. Moreover, spironolactone markedly increased the levels of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS and the activity of NO effector-protein kinase G (PKG) in the liver. CONCLUSION: Spironolactone lowers portal hypertension by improvement of liver fibrosis and inhibition of intrahepatic vasoconstriction via down-regulating ROCK-2 activity and activating NO/PKG pathway. Thus, early spironolactone therapy might be the optional therapy in cirrhosis and portal hypertension.

Aldosterone induction of hepatic stellate cell contraction through activation of RhoA/ROCK-2 signaling pathway.

The RhoA/ROCK-2 signaling pathway is necessary for activated hepatic stellate cell (HSC) contraction. HSC contraction plays an important role in the pathogenesis of cirrhosis and portal hypertension. This study investigated whether aldosterone contributes to HSC contraction by activation of the RhoA/ROCK-2 signaling pathway. Primary HSCs were isolated from Sprague-Dawley rats via in situ pronase/collagenase perfusion. We found that aldosterone enhanced the contraction of a collagen lattice seeded with HSCs. This induced contraction was suppressed by the mineralcorticoid receptor (MR) inhibitor spironolactone, the ROCK-2 inhibitor Y27632, and the angiotensin II type 1 receptor (AT(1)R) inhibitor irbesartan. Moreover, actin fiber staining showed that aldosterone significantly increased actin fiber formation in HSCs. Pre-incubating with spironolactone, Y27632, or irbesartan inhibited the aldosterone-induced actin fiber reorganization. Molecularly, the effect of aldosterone on activation of HSC contraction was mediated by phosphorylated myosin light chain (P-MLC) through the RhoA/ROCK-2 signaling pathway. All these inhibitors had the ability to block aldosterone-induced protein expressions in the RhoA/ROCK-2/P-MLC cascade in HSCs. Taken together, our current study suggests that aldosterone induces contraction of activated HSCs through the activation of the RhoA/ROCK-2 signaling pathway. This finding may provide a potential therapeutic target for control of cirrhosis and portal hypertension.

[The protective effects of bifidobacterial adhesin on ischemic reperfusion injury of intestine in rats].

OBJECTIVE: To investigate the protection effect of bifidobacterial adhesin for intestine ischemia/reperfusion (I/R) injury on gut barrier function in rat. METHODS: Seventy-two male SD rats were randomly divided into sham operation group (n = 24), I/R model group (n = 24) and pretreatment group of bifidobacterial adhesin (pretreatment group, n = 24). Six rats were anatomized at 6 h, 1 d, 4 d and 7d after inducing I/R model in each group, respectively. The pathological changes of the terminal ilea and the blood levels of TNFα, IL-6, IL-10, diamine oxidase (DAO), and the activity and content of D-lactic acid were observed. RESULTS: The blood levels of TNFα, IL-6, DAO and D-lactic acid in I/R model group were significantly higher than sham operation group at all time points (P < 0.05), while the blood level of IL-10 was no significantly change. The activity of IL-6 and DAO in pretreatment group was significantly lower than I/R model group at all time points (P < 0.05), the blood level of TNFα in pretreatment group was significantly lower than I/R model group at 1 d, the blood level of D-lactic was significantly lower than I/R model group at 4 d and 7 d (P < 0.05). Intestinal pathological damages were obviously milder in pretreatment group than I/R model group at all time points (Chiu's pathological scores: 6 h, 3.22 ± 0.22 vs 3.57 ± 0.20; 1 d, 3.77 ± 0.13 vs 3.90 ± 0.12; 4 d, 2.93 ± 0.23 vs 3.07 ± 0.21; 7 d, 2.10 ± 0.30 vs 2.22 ± 0.17, all P < 0.05). CONCLUSION: The pretreatment of bifidobacterial adhesin could protect the intestinal mucosa from I/R injury, and alleviate intestinal ischemic reperfusion injury.

Curcumin protects intestinal mucosal barrier function of rat enteritis via activation of MKP-1 and attenuation of p38 and NF-κB activation.

BACKGROUND: Intestinal mucosa barrier (IMB) dysfunction results in many notorious diseases for which there are currently few effective treatments. We studied curcumin's protective effect on IMB and examined its mechanism by using methotrexate (MTX) induced rat enteritis model and lipopolysaccharide (LPS) treated cell death model. METHODOLOGY/PRINCIPAL FINDINGS: Curcumin was intragastrically administrated from the first day, models were made for 7 days. Cells were treated with curcumin for 30 min before exposure to LPS. Rat intestinal mucosa was collected for evaluation of pathological changes. We detected the activities of D-lactate and diamine oxidase (DAO) according to previous research and measured the levels of myeloperoxidase (MPO) and superoxide dismutase (SOD) by colorimetric method. Intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNF-α) and interleukin 1ß (IL-1ß) were determined by RT-PCR and IL-10 production was determined by ELISA. We found Curcumin decreased the levels of D-lactate, DAO, MPO, ICAM-1, IL-1ß and TNF-α, but increased the levels of IL-10 and SOD in rat models. We further confirmed mitogen-activated protein kinase phosphatase-1 (MKP-1) was activated but phospho-p38 was inhibited by curcumin by western blot assay. Finally, NF-κB translocation was monitored by immunofluorescent staining. We showed that curcumin repressed I-κB and interfered with the translocation of NF-κB into nucleus. CONCLUSIONS/SIGNIFICANCE: The effect of curcumin is mediated by the MKP-1-dependent inactivation of p38 and inhibition of NF-κB-mediated transcription. Curcumin, with anti-inflammatory and anti-oxidant activities may be used as an effective reagent for protecting intestinal mucosa barrier and other related intestinal diseases.

[Effect of small interfering RNA targeting Rac1 gene on colony formation of SW480 cells in vitro].

OBJECTIVE: To construct a vector expressing small interfering RNA (siRNA) against Rac1 gene and observe its effect on soft agar colony formation of SW480 cells in vitro. METHODS: Oligos of 64 base pairs for hairpin RNA targeting Rac1 were chemically synthesized and annealed. The siRNA constructs for Rac1, produced by inserting the annealed oligos into the downstream of H1 promoter of linearized pSUPER, were confirmed by restriction digestion and DNA sequencing. The constructed Rac1-siRNA was transfected into SW480 cells and Western blotting was performed to assess the expression and interference efficiency of siRNAs against Rac1.The soft agar colony formation assay was used to study the effect of Rac1 gene silencing on SW480 cells. RESULTS: Restriction digestion and DNA sequencing showed that the siRNA targeting Rac1 gene was successfully constructed. The siRNA could effectively down-regulate the expression of Rac1 in SW480 cells. Soft agar colony formation assay showed that the colony number and diameter of SW480 cells was reduced after siRNA transfection. CONCLUSION: A vector expressing hairpin RNA against Rac1 gene are successfully produced, which significantly reduces the colony numbers and size of SW480 cells in vitro, suggesting that Rac1 plays an important role in the growth of colorectal cancer in vitro.

[Effect of partial splenic embolization in prevention of gastroesophageal variceal rebleeding].

OBJECTIVE: To evaluate the effect of partial splenic embolization (PSE) in prevention of gastroesophageal variceal rebleeding. METHODS: Sixty-two patients with recent gastroesophageal variceal bleeding were treated by PSE with Seldinger technique. All the patients were followed-up for 12 months. The data including peripheral blood cell count, liver function, plasma prothrombin time (PT), portal vein diameter, and appearance of gastroesophageal varices under gastroscopy were collected before and after embolization for statistical analysis. RESULTS: Five days after the operation, the numbers of leucocytes and platelets were significantly increased (P<0.05), and PT was significantly shortened (P<0.05). All the patients showed a good response after PSE with reduced internal diameter of the portal vein and blood flow (P<0.05). Gastroesophageal varices were relieved in all the patients. Rebleeding occurred in 11 patients during the follow-up. CONCLUSION: PSE can be effective in preventing gastroesophageal variceal rebleeding.

Upregulation of angiotensin-converting enzyme (ACE) 2 in hepatic fibrosis by ACE inhibitors.

1. The role of angiotensin-converting enzyme (ACE) 2 is likely to balance the status of the renin-angiotensin system (RAS) by degrading angiotensin (Ang) II and generating Ang-(1-7). Earlier demonstrations that ACE2 is insensitive to ACE inhibitors prompted us to evaluate the effect of ACE inhibitors on ACE2 expression. 2. Liver fibrosis was induced in rats with 40% CCl(4) (2.5 mL/kg, s.c., twice per week). Half the rats were further treated with perindopril (2 mg/kg, p.o., daily). After 2 and 4 weeks treatment, ACE2 immunoreactivity was assessed by immunohistochemical staining, ACE2 protein expression was determined by western blot and mRNA expression of ACE2 and the Ang-(1-7) receptor Mas was determined by reverse transcription-polymerase chain reaction (RT-PCR). 3. As an in vitro study, hepatic stellate cells (HSC) were treated with AngII (0.1-10 micromol/L) alone or in combination with the synthesized peptide ACEI (Sigma-Aldrich). Western blot and RT-PCR were used to evaluate ACE2 expression and Mas mRNA levels. Furthermore, after treatment of HSC with the Mas antagonist A779 (1 micromol/L), the protein expression of connective tissue growth factor (CTGF) was detected to evaluate the interaction between AngII, ACEI and the ACE2-Mas axis. 4. Expression of both ACE2 mRNA and protein and Mas mRNA was markedly upregulated in both CCl(4)-injured rat liver and AngII-treated HSC. Further significant upregulation was observed following additional administration of ACEI. In addition, ACEI treatment of HSC inhibited AngII-induced overexpression of connective tissue growth factor and this effect was ameliorated by blockade of the Mas receptor with A779. 5. The findings of the present study suggest that ACE inhibitors are able to upregulate ACE2 under conditions of liver injury both in vivo and in vitro, which may indicate potential benefits of ACE inhibitors in the therapeutic treatment of liver fibrosis.

Soluble intercellular adhesion molecule-1, D-lactate and diamine oxidase in patients with inflammatory bowel disease.

AIM: To study the levels of serum soluble intercellular adhesion molecule-1 (sICAM-1), plasma D-lactate and diamine oxidase (DAO) in patients with inflammatory bowel disease (IBD), and the potential clinical significance. METHODS: Sixty-nine patients with IBD and 30 healthy controls were included in this study. The concentration of sICAM-1 was detected with enzyme-linked immunosorbent assay, the level of D-lactate and DAO was measured by spectroscopic analysis, and the number of white blood cells (WBC) was determined by routine procedure. RESULTS: The levels of sICAM-l, DAO, and WBC in IBD patients were significantly higher than those in the control group (P < 0.01). sICAM-l in IBD patients was found to be closely related to the levels of DAO and D-lactate (212.94 +/- 69.89 vs 6.35 +/- 2.35, P = 0.000), DAO 212.94 +/- 69.89 vs 8.65 +/- 3.54, P = 0.000) and WBC (212.94 +/- 69.89 vs 7.40 +/- 2.61, P = 0.000), but no significant difference was observed between patients with ulcerative colitis and patients with Crohn's disease. The post-treatment levels of sICAM-l, D-lactate and WBC were significantly lower than before treatment (sICAM-l 206.57 +/- 79.21 vs 146.21 +/- 64.43, P = 0.000), (D-lactate 1.46 +/- 0.94 vs 0.52 +/- 0.32, P = 0.000) and (WBC 7.24 +/- 0.2.33 vs 5.21 +/- 3.21, P = 0.000). CONCLUSION: sICAM-1, D-lactate and DAO are closely related to the specific conditions of IBD, and thus could be used as a major diagnostic index.

[Effect of p21-activated kinase-1 on the invasiveness of colorectal carcinoma cells in vitro].

OBJECTIVE: To observe the effect of p21-activated kinase-1 (PAK1) gene transfection on the invasiveness of human colorectal carcinoma SW480 cells in vitro. METHODS: SW480 cells in routine culture were transfected with the recombinant plasmid EGFP-C1/PAK1 via Lipofectamine(TM) 2000. The expression of PAK1 protein in SW480 cells was detected using Western blotting, and the changes of the invasiveness of SW480 cells were evaluated using Boyden chamber invasion assay. RESULTS: Forty-eight hours after transfection with pEGFP-C1/ PAK1, the PAK1 protein expression increased significantly in comparison with those in negative and vector control groups. The invasiveness of the SW480 cells was significantly enhanced after the transfection. CONCLUSION: The PAK1 gene transfection can increase the expression of PAK1 in SW480 cells and enhance the invasiveness of the cells. PAK1 can be associated with the invasiveness and metastasis of colorectal carcinoma cells.

[Effect of angiotensin1-7 on alpha-smooth muscle actin protein expression in rat hepatic stellate cells].

OBJECTIVE: To investigate the effect of angiotensin II and angiotensin1-7 on alpha-smooth muscle actin (alpha-SMA)-induced Ca(2+)-independent pathways mediated by Rho kinase2 in hepatic stellate cells (HSCs). METHODS: HSC-T6 cells were treated with 10 micromol/L of AngII, Ang1-7, AngII +Ang1-7, and Ang1-7+A779. RT-PCR was used to detect the expression of Rho kinase2 (Rock2) in Ca(2+)-independent pathways, and alpha-SMA protein expression was detected by Western blotting. RESULTS: The mRNA expression of Rock2 increased significantly in the cells after AngII treatment (P<0.01), but decreased following Ang1-7 treatment. Ang1-7 treatment significantly reduced alpha-SMA level in AngII-induced cells (P<0.01). CONCLUSION: Ang1-7 can inhibit AngII-induced activation of Rock2 and reduce alpha-SMA expression in HSCs.

[Effect of angiotensin II type 1 receptor and angiotensin-converting enzyme gene silencing on nuclear factor-kappaB activity in hepatic stellate cells].

OBJECTIVE: To investigate the effect of angiotensin II (AngII) type 1 (AT-1) receptor and angiotensin-converting enzyme (ACE) gene silencing on nuclear factor-kappaB (NF-kappaB) activity in hepatic stellate cells (HSCs). METHODS: pSilencer/AT-1 alpha receptor siRNA and pSilencer/ACE siRNA plasmids were transfected into cultured HSC-T6 cells, which were subsequently stimulated by 10(-6) mol/L AngII or ACE inhibitor (ACEI). The DNA binding activity of NF-kappaB in the transfected cells was analyzed using electrophoretic gel mobility shift assay (EMSA). RESULTS: s Gel shift studies showed that stimulation of the HSCs by AngII markedly increased the DNA-binding activity of NF-kappaB, which was inhibited by the transfection with pSilencer/ AT-1 alpha receptor siRNA plasmid or pSilencer/ACE siRNA plasmid. CONCLUSION: AT-1 alpha receptor and ACE gene silencing result in inhibition of NF-kappaB activity in HSCs in vitro.

[Effect of AT-1 alpha receptor gene silencing on nuclear factor-kappaB activity in hepatic Kupffer cells].

OBJECTIVE: To investigate the effect of angiotensin II type-1 (AT-1) alpha receptor gene silencing on nuclear factor-kappaB (NF-kappaB) activity in hepatic Kupffer cells. METHODS: The expression of AT-1 alpha receptors in primary isolated cultured hepatic Kupffer cells was detected by immunohistochemistry. pSilencer/AT-1 alpha receptor siRNA plasmids were transfected into Kupffer cells, which were subsequently exposed to 10(-6) mol/L angiotensin II (Ang II) for 60 min. The changes in the DNA binding activity of NF-kappaB in the cells was assessed using electrophoretic gel mobility shift assay (EMSA). RESULTS: AT-1 alpha receptor expression was detected in Kupffer cells. NF-kappaB DNA binding activity was markedly increased in Kupffer cells after Ang II stimulation, and obviously inhibited by transfectiom with pSilencer/AT-1 alpha receptor siRNA plasmid. CONCLUSION: Ang II stimulation of Kupffer cell results in increased activation of NF-kappaB via AT-1 alpha receptor.

Inhibition of migration and invasion of colorectal cancer cells via deletion of Rac1 with RNA interference.

Cell migration and invasion are triggered by a number of chemoattractants that stimulate intracellular signaling pathways through regulating reorganization of the actin cytoskeleton. Rac1, an intracellular signal transducer, regulates a variety of cell functions, including the organization of the cytoskeleton, cell migration, and invasion. However, currently, very little is known about the roles of Rac1 in the cytoskeleton formation and invasion of human colorectal cancer cells. In our study, Rac1-shRNA was used to silence the Rac1 to reduce its expression specifically in Lovo cells. Our studies showed that RNA interference-mediated deletion of Rac1 strongly inhibited lamellipodia formation, cell migration, and invasion of Lovo cells in vitro. The deletion of Rac1 can serve as an alterative therapy to inhibit the invasion and metastasis of colorectal cancer cells.

[Detection of interferon-induced transmembrane-1 gene expression for clinical diagnosis of colorectal cancer].

OBJECTIVE: To investigate the expression of the interferon-induced transmembrane-1 (IFITM1) gene in colorectal cancer (CRC) tissue and the serum anti-IFITM1 antibody responses of the patients and assess their value in clinical diagnosis of CRC. METHODS: Semi-quantitative RT-PCR was performed to detect IFITM1 mRNA expression in the specimens of normal colonic mucosa, CRC tissue, inflammatory polyps, adenomatous polyps, gastric cancer, esophageal carcinoma and liver cancer tissues. Serum samples were collected from the patients to detect anti-IFITM1 antibody responses using Western blotting. The clinicopathological features of the carcinoma expressing IFITM1 gene were analyzed. RESULTS: IFITM1 mRNA was expressed in 47.4 % (18/38) of the CRC specimens, a rate significantly higher than that in adenomatous polyps [15% (3/20)] and gastric cancer [4.8% (1/21)]; no obvious IFITM1 expression was found in normal colonic mucosa, inflammatory polyp, esophageal carcinoma or liver cancer tissues (P<0.001 or P<0.05). IFITM1 mRNA was strongly expressed in CRC at the expression level of 0.8048-/+0.2273, which was significantly higher than that in adenomatous polyps (0.4447-/+0.0989, P<0.001). No anti-IFITM1 antibody response was detected in healthy human sera, but in the CRC patients, the serum antibody response was detected at the rate of 36.8% (14/38), significantly higher than the rate of 9.5% (2/21) in gastric cancer (P<0.05). No antibody response was detected in esophageal carcinoma, liver cancer, inflammatory polyp or adenomatous polyps. Most of the IFITM1-expressing CRC had a diameter exceeding 5 cm, often invading the serous membrane with metastasis to the lymph nodes and the distant organs; these tumors were identified mostly as well-differentiated adenocarcinoma in Dukes stage C or D. CONCLUSION: IFITM1 gene may play an important role in the pathogenesis, development and metastasis of CRC, and may serve as a potential biomarker for clinical diagnosis of CRC.

[Angiotensin II stimulates platelet-derived growth factor-B expression in hepatic stellate cells by activating EGR-1].

OBJECTIVE: To investigate the signal transduction mechanism underlying the effects of angiotensin II (AngII) on extracellular signal-regulated kinase 1/2 (ERK1/2), early growth response-1 (EGR-1) and platelet-derived growth factor-B (PDGF-B) in hepatic stellate cells (HSCs). METHODS: HSC-T6 cells treated with AngII for 10 or 30 min were examined for phospho-P42/44 protein expression using Western blotting. In another experiment, the cells were preincubated for 1 h in the presence of U0126 (an inhibitor of the MAPK/ERK kinase), irbesartan (an AT-1 receptor blocker), or antioxidant-N-acetylcysteine (NAC) prior to AngII exposure, and the protein expression of phospho-P42/44 and PDGF-B were measured with Western blotting. The DNA binding activity of EGR-1 was analyzed using electrophoretic gel mobility shift assay (EMSA), and the expression of PDGF-B was detected immunohistochemically. RESULTS: AngII induced phospho-P42/44 expression in HSC-T6, which was abrogated by U0126 or irbesartan. NAC did not inhibit phospho-P42/44 expression. EMSA showed that AngII exposure of the HSC cells markedly increased EGR-1 DNA binding activity, reaching the maximum after 60 min of exposure followed by progressive declination; irbesartan and U0126 significantly suppressed AngII-induced EGR-1 activity enhancement. ACEI at 1 micromol/L and 10 nmol/L inhibited EGR-1 activity, but ACEI at the concentration of 0.1 nmol/L resulted in enhanced EGR-1 activity. NAC showed no obvious effect in suppressing EGR-1 activity. AngII increased PDGF-B protein level in the HSCs, the effect of which was inhibited by irbesartan. U0126, NAC and ACEI did not attenuate PDGF-BB protein level in the HSCs. CONCLUSION: Stimulation of the HSCs with AngII results in EGR-1 activation via the ERK1/2 pathway, leading to up-regulation of PDGF-B expression.

[Construction and identification of recombinant Lactococcus lactis highly expressing human granulocyte-macrophage colony stimulating factor].

OBJECTIVE: To transfer human granulocyte-macrophage colony stimulating factor (hGM-CSF) gene into Actococcus lactis and obtain recombinant Lactococcus lactis highly expressing hGM-CSF (LL-CSF). METHODS: The optimized hGM-CSF gene sequence capable of expression in Lactococcus lactis was cloned into the vector pNBC1000, which contained P59 promoter, RBS, MCS, USP45 signal peptide and USP45 stop codon, to generate the recombinant plasmid pNCSF. pNCSF was subcloned into a shuttle vector pTR1001c to acquire the plasmid pTRCSF, which was transferred into Lactococcus lactis to obtain LL-CSF by means of electroporation. SDS-PAGE was used to verify the expression of hGM-CSF protein by the constructed LL-CSF. RESULTS: DNA sequencing and restriction enzyme digestion indicated the successful construction of the recombinant plasmid pNCSF, pTRCSF and the recombinant bacterium LL-CSF that was capable of steady and efficient expression of hGM-CSF as shown by SDS-PAGE. CONCLUSION: The recombinant Lactococcus lactis LL-CSF has been successfully constructed, which can be valuable for studying the biological activity of recombinant hGM-CSF and for evaluating the potential clinical application of the protein.

[Protective effect of curcumin against methotrexate-induced small intestinal damage in rats].

OBJECTIVE: To observe the changes in intestinal mucosal permeability in rats with methotrexate (MTX)-induced small intestinal damage and investigate the protective effects of curcumin. METHODS: The experiment was carried out using 4 groups of rats, namely the normal control group, enteritis model group, sulfasalazine (SASP) group and curcumin group. With the exception of the rats in the normal control group, all rats were subjected to intraperitoneal MTX injection to induce enteritis and received subsequent daily intragastric administration of SASP (100 mg/kg), curcumin (100 mg/kg), or normal saline for 5 days. The disease activity index (DAI), colonic mucosal damage index (CMDI) and histological score (HS) of the rats were evaluated. The levels of diamine oxidase (DAO) and D-lactate were assessed using spectrophotometric assay, and myeloperoxidase (MPO) activity and intracellular adhesion molecule-1 (ICAM-1) protein expression were measured by biochemical and immunohistochemical methods, respectively. RESULTS: Compared with the normal control group, the rats in the model group showed significantly increased DAI, CMDI and HS and levels of DAO, D-lactate, ICAM-1 and MPO. Curcumin treatment resulted in significantly decreased DAI, CMDI, HS and lowered activities of D-lactate, ICAM-1 and MPO in comparison with the model group (P<0.01). CONCLUSION: MTX induces increased mucosal permeability of the small intestines in rats, and curcumin may offer protective effects against MTX-induced rat enteritis by lowering the intestinal mucosal permeability.