The Role Of JAKs/STATs Pathway In Glomerulosclerosis And Effects Of Matrine Of It

The accumulating evidence suggests that cytokines such as transforminggrowth factorβ₁(TGFβ₁) and connective tissue growth factor (CTGF) plays akey role in the development of glomerulosclerosis (GS). Most of thosecytokines were produced by the proliferated glomerular mesangial cell (MsC).They can induce abnormal accumulation of extracellular matrix (ECM) and theresident cells-myofiblast transdifferentiation which contribute to theprogress of GS. The Janus kinase-signal transducers and activators oftranscription (JAKs/STATs) pathway is an essential intracellular mechanism ofcytokine actions and constitutes a link between activation of cell surfacereceptors and nuclear transcriptional event. Recent findings have indicated akey role of STAT1and STAT3 activation in a number of kidney diseases, and itis likely that STAT1 and STAT3 may represent new moleculars target for thetreatment. However, little is known about the pathogenic significance ofJAKs/STATs in GS. To better understand the pathogenic significance ofJAKs/STATs in GS and how the STAT s function is regulated, we carried outthis research.Matrine (MT) and Oxymatrine (OMT) are the major quinolizidine alkaloidsin the roots of of traditional Chinese medical herb sophora flavescens ait. It isreported that OMT taken orally can be reduced to MT, which is moreabsorbable by intestinal bacteria. Basic and clinical research suggests thatoxymatrine and matrine have a variety of pharmacological activities, includinganti-cancer, anti-inflammatory, antipyretic, analgesic, anti-arrhythmia effectsand immune regulation, anti-virus properties, hepatocyte-protected effect andanti-hepatic fibrosis action.Our long-term research had proved that matrine could significantly inhibitthe proliferation of rat glomerular mesangial cell, extracellular matrix and ndthe resident cells-myofiblast transdifferentiation in vitro and in vivo. But themechanism of matrine on glomerulosclerosis is still not clear. To explore the effect and probable mechanism of matrine on glomerulosclerosis, the changesof JAKs/STATs pathway molecules and endogenous feedback inhibitors wereobserved in the FSGS rat model. These results will provide clues for matrine tobe developed to prevent and treat glomerulosclerosis.Part One: Expression of JAKs/STATs pathway molecules in ratmodel of glomerulosclerosisObjective The purposes of this study were to dynamically measure thelevels of JAKs/STATs pathway molecules in glomerulosclerosis rat model andto assess their effect on the pathological process.Medthods Sixty male Wistar rats were randomly divided into two groups:model group and normal control group. Adriamycin nephropathy was inducedby lateral nephrectomy at the right side and a single tail intravenous injection ofadriamycin (5mg/kg). Ten rats were sacrificed every 2 weeks in both groups.Immunohistochemistry was used to examine the expression ofα-SMA andCOL-IV. Western-boltting was used to examine the expression of STAT1,STAT3, P-STAT1, P-STAT3 and TGFβ1 protein. Finally, the expressions ofJAK1, JAK2, STAT1, STAT3, SOCS1, SOCS3, PIAS1 and PIAS3 mRNA weremeasured by real-time quantitative RT-PCR.Resultsα-SMA, COL-IV and TGFβ1 protein expression graduallyincreased in model group, and much higher than normal control group at 6week. STAT1 and P-STAT1 protein expression in model group increased at 4week compared with the normal control group. STAT3 and P-STAT3 proteinexpression in model group increased at 2week. The mRNA level of JAK2,STAT1, STAT3, PIAS1 in model group was significantly increased comparedwith the normal control group and showed developing change. SOCS3 mRNAshow significantly increased compared with the normal control group in week2,then decreased. JAK1, SOCS1 and PIAS3 mRNA expression in model have a trend of initially increased and then decreased, and increased finally.Conclusions JAKs/STATs singaling pathway and endogenous feedbackinhibitors may play an important role in the pathological process of rapid focalsegmental glomerulosclerosis in rat model.Part Two: Investigation the effect of matrine on JAKs/STATspathway molecules in rat model of glomerulosclerosisObjective To observe the effects of matrine on the levels of JAKs/STATspathway molecules in focal segmental glomerulosclerosis rat model and toexplore its mechanism.Medthods The experiments were performed on 90 male Wistar rats. The ratswere randomly divided into 3 groups: normal control group, model group,matrine treatment group(25mg/kg·d). The rats of normal control group weresubjected to sham operation and were injected with normal saline via the tailvein one week later. The rats of the other groups were uninephrectomized andinjected with adriamycin (5 mg/kg) via the tail vein one week later. Matrinetreatment group were given by gastric perfusion from the first day after theoperation. The level of urinary protein, serum creatinine (Scr) and blood ureanitrogen (BUN) were measured at 6th week after the operation. The degree ofglomerular lesions were evaluated by masson stain. The expression ofCOL-IV,α-SMA, STAT1,STAT3 protein in glomerulus were examined byimmunohistochemistry.The expressions of JAK1, JAK2, STAT1, STAT3,SOCS1, SOCS3, PIAS1 and PIAS3 mRNA were measured by real-timequantitative RT-PCR.Results Matrine not only reduced the excretion of urinary protein and thelevel of serum creatinine and BUN, but also significantly amelioratedglomerular sclerosis and COL-IV,α-SMA protein expression (P＜0.05,respectively). Decreased STAT1 protein level in matrine treatment was observed by week 6. Significantly decreased STAT3 protein level was noted inmatrine treatment group in the whole time. The expressions of JAK1, JAK2,STAT1 and STAT3 mRNA were decreased in matrine treatment group ascompared to the model group (P＜0.05). The expressions of SOCS1, SOCS3and PIAS3mRNA were increased in three treatment groups as compared tothe model group (P＜0.05).Conclusions Matrine has a renoprotective effect on experimentalglomerulosclerosis in rats. The possible mechanism might relate tointervention of the JAKs/STATs signaling pathway.