γ链族细胞因子在心肌缺血再灌注及预处理中的变化及意义

目的探讨γ链族细胞因子及磷酸化酪氨酸蛋白激酶1(p-JAK1)、磷酸化传导及转录激活因子3(p-STAT3)蛋白在大鼠心肌缺血再灌注损伤及缺血预处理中表达变化及作用机制。方法雄性SD大鼠18只,随机分为假手术组、心肌缺血再灌注组、缺血预处理组,采用结扎左前降支法制作大鼠心肌缺血再灌注损伤模型,缺血时间30 min,再灌注后120 min处死大鼠。检测血清心肌肌钙蛋白T(cTnT)、乳酸脱氢酶(LDH)含量,以及血清γ链族细胞因子IL-2、4、15的水平;Western blot检测p-JAK1,p-STAT3蛋白表达水平的变化。结果与心肌缺血再灌注组相比,缺血预处理组血清cTnT、LDH减少(P<0.05),IL-2、IL-15水平降低(P<0.05),IL-4水平增加(P<0.05);p-JAK1,p-STAT3表达减少(P<0.05)。以上两组上述指标水平均高于假手术组。结论缺血预处理可以通过激活γ链族细胞因子的释放,适度的激活JAK1/STAT3信号转导通路发挥心肌保护作用。

第10号染色体丢失性磷酸酶及张力蛋白同源基因调控的酪氨酸蛋白激酶2/信号传导与转录因子3信号通路对糖尿病心肌缺血后处理敏感性的作用

目的 评价第10号染色体丢失性磷酸酶及张力蛋白同源基因（PTEN）调控的酪氨酸蛋白激酶2/信号传导与转录因子3（JAK2/STAT3）信号通路在糖尿病心肌对缺血后处理敏感性中的作用.方法 健康雄性SD大鼠,体重220～ 280 g,采用1％链脲佐菌素-柠檬酸盐缓冲液60 mg/kg腹腔注射法制备1型糖尿病模型.8周后取成模糖尿病大鼠60只,采用随机数字表法分为5组（每组12只）：假手术组（S组）、缺血再灌注组（I/R组）、缺血后处理组（IPO组）、PrEN抑制剂BpV＋缺血再灌注组（BpV＋I/R组）、BpV＋缺血后处理组（BpV＋IPO组）.I/R组采用结扎左冠状动脉前降支30 min,再灌注120 min的方法建立模型;IPO组于再灌注前行3个循环的再灌注10 s/缺血10 s;S组只穿线不结扎血管;BpV于缺血前lh静脉注射1 mg/kg,对照组注射等量生理盐水.各组于再灌注120 min时处死大鼠,测定血清肌酸激酶同工酶（CK-MB）的水平,心肌梗死面积（IS）和细胞凋亡指数（AI）,PTEN活性及其蛋白表达,磷酸化JAK2（p-JAK2）、磷酸化STAT3（p-STAT3）以及凋亡相关蛋白活化的半胱酰天冬氨酸特异性蛋白酶3（cleaved caspase-3）的表达水平.多组间数据比较采用单因素方差分析,两组间比较采用t检验.结果 与S组比较,I/R组和IPO组血清CK-MB水平及PTEN活性升高,PTEN和cleaved caspase-3表达上调（t=2.997～ 7.702,均P＜0.05）;与IPO组比较,BpV＋IPO组血清CK-MB水平、IS和AI及PTEN活性降低,p-JAK2和p-STAT3的表达上调,cleaved caspase-3的表达下调[分别为3 003±613比1 247± 440、42％±8％比53％±6％、21％±3％比33％±6％、（584±78）比（918±136） pmol、1.73±0.29比1.06±0.24、1.75±0.19比1.01±0.16、1.6±0.4比2.2±0.5,t=2.837～9.249,均P＜0.05].I/R组与IPO组,BpV＋I/R组与I/R组比较上述指标差异无统计学意义.结论 PTEN抑制可通过激活JAK2/STAT3信号通路从而恢复缺血后处理对糖尿病再灌注损伤心肌的保护作用。

STAT3 signal that mediates the neural plasticity is involved in willed-movement training in focal ischemic rats

Willed-movement training has been demonstrated to be a promising approach to increase motor per- formance and neural plasticity in ischemic rats. However, little is known regarding the molecular signals that are in- volved in neural plasticity following willed-movement training. To investigate the potential signals related to neural plasticity following willed-movement training, littermate rats were randomly assigned into three groups： middle cerebral artery occlusion, environmental modification, and willed-movement training. The infarct volume was measured 18 d after occlusion of the right middle cerebral artery. Reverse transcription-polymerase chain reaction （PCR） and im- munofluorescence staining were used to detect the changes in the signal transducer and activator of transcription 3 （STAT3） mRNA and protein, respectively. A chromatin immunoprecipitation was used to investigate whether STAT3 bound to plasticity-related genes, such as brain-derived neurotrophic factor （BDNF）, synaptophysin, and protein in- teracting with C kinase 1 （PICK1）. In this study, we demonstrated that STAT3 mRNA and protein were markedly increased following 15-d willed-movement training in the ischemic hemispheres of the treated rats. STAT3 bound to BDNF, PICK1, and synaptophysin promoters in the neocortical cells of rats. These data suggest that the increased STAT3 levels after willed-movement training might play critical roles in the neural plasticity by directly regulating plasticity-related genes.

Protein tyrosine phosphatase 1B expression contributes to the development of breast cancer

The protein tyrosine phosphatase 1B（PTP1B）is an important regulator of metabolism.The relationship between PTP1B and tumors is quite complex.The purpose of this study is to explore the expression pattern and role of PTP1B in breast cancer.The expression of PTP1B was detected in 67 samples of breast cancer tissue by Western blot.Cell growth assay,Transwell migration assay,and Scratch motility assay were used to examine the proliferation and migration of MCF-7 with and without PTP1B.The total levels and phosphorylated levels of signal transduction and activator of transcription 3（STAT3）and the expression of C-C motif chemokine ligand 5（CCL5）were also examined by Western blot.PTP1B was overexpressed in over 70%of breast cancer tissues,correlating with patients with estrogen receptor（ER）-negative,progesterone receptor（PR）-negative,and human epidermal growth factor receptor 2（HER2）-positive tumors.The data also showed that both tumor size and lymph node metastasis were significantly higher in patients with a higher level of PTP1B.The proliferation and migration of MCF-7 cells were found to be inhibited after knocking down the gene of PTP1B.Our data also showed that PTP1B could up-regulate the dephosphorylated level of STAT3,which could increase the expression of CCL5.These phenomena indicated that PTP1B may play a crucial role in the development of breast cancer.