Diabetic kidney disease (DKD) is a major cause of end stage renal diseases worldwide. Despite successive interventions for delaying the progression of DKD, current treatments cannot reverse the pathological progression. Mefunidone (MFD) is a new compound with potent antifibrotic properties, but the effect of MFD on DKD remains unknown. Therefore, we investigated the protective effects of MFD in both models of the db/db type 2 diabetes (T2D) and streptozotocin (STZ)-induced type 1 diabetes (T1D) models. Compared with the model group, MFD treatment significantly reduced pathological changes observed by PAS staining, PASM staining, and Masson staining in vivo. To further elucidate the potential mechanisms, we discovered MFD treatment notably restored podocyte function, alleviated inflammation, abated ROS generation, inhibited the TGF-β1/SAMD2/3 pathway, suppressed the phosphorylation levels of MAPKs (ERK1/2, JNK, and P38), and reduced epithelial-to-mesenchymal transition(EMT). In conclusion, these findings demonstrate the effectiveness of MFD in diabetic nephropathy and elucidate its possible mechanism.

Objective To investigate the effects of fluorofenidone(AKF-PD)on diabetic kidney disease in db/db mice and its possible mechanisms.Methods(1)Fifty-six mice aged 8 weeks(half male and half female),including 42 db/db mice and 14 wild-type mice were studied.Fortytwo db/db mice randomly were divided into model group(mock-treated diabetic db/db mice),AKF-PD(250 mg· kg-1· d-1)treatment group and losartan(20 mg· kg-1· d-1)treatment group.Wild-type mice and model mice were treated with vehicle(0.5％sodium carboxymethylcellulose),while the treatment groups received either AKF-PD or losartan.After 18 weeks,the blood glucose and urinary albumin were measured,the pathological changes of kidney were observed by PAS staining.The protein expressions of type Ⅳ collagen and fibronectin(FN)in kidney tissue were detected by immunohistochemistry.(2)Mouse glomerular mesangial cells(MES-13 cells)were divided into six groups:normal glucose group(5.5 mmol/L glucose),hypertonic group(5.5 mmol/L glucose+19.5 mmol/L mannitol),high glucose group(25.0 mmol/L glucose),AKF-PD group(25.0 mmol/L glucose+400 mg/L AKF-PD)and losartan group(25.0 mmol/L glucose+2 μmol/L losartan).After 72 h treatment,the expressions of type Ⅰ collagen,type Ⅳ collagen and transforming growth factor-β1(TGF-β1)mRNA were detected by realtime PCR,and the content of TGF-β1 protein in the culture supernatant was detected by ELISA.Results(1)Compared with the wild type mice,model mice had increased weight,blood glucose and glomerulosclerosis index(all P ＜ 0.01),accompanied with heavy albuminuria,glomerular hypertrophy,mesangial area expansion and deposition of collagen type Ⅳ and FN(all P ＜ 0.01).Compared with model mice,in AKF-PD and losartan groups 24 h urinary albumin and glomerulosclerosis index decreased(all P ＜ 0.01),glomerular hypertrophy and mesangial area expansion alleviated,and the protein expressions of collagen type Ⅳ and FN were inhibited(all P ＜ 0.01).(2)Compared with the normal glucose group,the mRNA expressions of type Ⅰ collagen and type Ⅳ collagen increased in high glucose group,meanwhile the mRNA and protein expressions of TGF-β1 increased(all P ＜ 0.01).In AKF-PD and losartan groups the expressions of type Ⅰ collagen,type Ⅳ collagen and TGF-β1 were inhibited as compared with high glucose group(all P ＜ 0.05).Conclusion Fluorofenidone may play an anti-fibrotic effect in db/db mice by reducing the expression of TGF-β1 and inhibiting collagen synthesis in glomerular mesangial cells.

Objective To investigate effects of pirfenidone（PFD） on diabetic nephropathy model in db/db mice and to explore its possible mechanisms. Methods （1） Wildtype mice were as the normal control group,and db/db mice were divided into model group and PFD group,with6 mice in each group. In the PFD group mice were administered continuously by 250 mg·kg -1 ·d -1 PFD for

BACKGROUND/AIMS:Renal tubulointerstitial fibrosis (TIF) is the common pathway of progressive chronic kidney disease. Inflammation has been widely accepted as the major driving force of TIF. Cystathionine β-synthase (CBS) is the first and rate-limiting enzyme in the transsulfuration pathway. CBS is considered to play protective role in liver and pulmonary fibrosis, but its role in TIF remains unknown. The purpose of this study was to investigate the potential role and mechanism of CBS in renal inflammation and TIF.METHODS:Renal function, tubulointerstitium damage index score, extracellular matrix (ECM) deposition, and the expressions of collagen I, collagen III, fibronectin, CD3, CD68, IL-1β, TNF-α were measured in sham operation and unilateral ureteral obstruction (UUO) rats. Proteomics and gene array analysis were performed to screen differentially expressed molecules in the development of renal inflammation and TIF in UUO rats. The expression of CBS was detected in patients with obstructive nephropathy and UUO rats. We confirmed the expression of CBS using western blot and real-time PCR in HK-2 cells. Overexpression plasmid and siRNA were transfected specifically to study the possible function of CBS in HK-2 cells.RESULTS:Abundant expression of CBS, localized in renal tubular epithelial cells, was revealed in human and rat renal tissue, which correlated negatively with the progression of fibrotic disease. Expression of CBS was dramatically decreased in the obstructed kidney from UUO rats as compared with the sham group (SHM). In addition, knocking down CBS exacerbated extracellular matrix (ECM) deposition, whereas CBS overexpression attenuated TGF-β1-induced ECM deposition in vitro. Inflammatory and chemotactic factors were also increased in CBS knockdown HK-2 cells stimulated by IL-1β.CONCLUSIONS:These findings establish CBS as a novel inhibitor in renal fibrosis and as a new therapeutic target in patients with chronic kidney disease.

Mefunidone is a new pyridone agent that attenuates renal tubulointerstitial fibrosis. However, the signaling pathways involved in the effect of mefunidone on renal tubulointerstitial fibrosis have not been well explained. Inflammatory response initiates and promotes renal tubulointerstitial fibrosis, and the inhibitor of nuclear factor kappa-B kinase beta (IKKβ) is a master regulator of inflammation. This study is determined to clarify the influence of mefunidone on renal inflammation and the phosphorylation of IKKβ. Experimental renal tubulointerstitial fibrosis was induced by unilateral ureteral obstruction (UUO) for 3, 7 and 14days in sprague dawley rat. Treatment with mefunidone was conducted simultaneously. Obstructed kidneys were harvested for the assessment. Our results showed that treatment with mefunidone ameliorated renal inflammatory injury, renal tubular lesions and interstitial fibrosis. Further studies indicated that treatment with mefunidone mitigated the expressions of tumor necrosis factorα (TNFα) and interleukin-1β (IL-1β) in the kidney. The phosphorylation of IKKβ and inhibitor of kappa-B (IκB) and the expression of NOD-like receptor family, pyrin domain containing 3 (NALP3) were also reduced in vivo after treatment with mefunidone. In vitro, peritoneal macrophages were incubated with necrotic cells or lipopolysaccharide in the presence or absence of mefunidone. Mefunidone markedly decreased necrotic cell or LPS induced IL-1β production and LPS induced TNFα production in primary peritoneal macrophages. Furthermore, mefunidone significantly inhibited the phosphorylation of IKKβ/IκB and nuclear transition of NF-κB p65 in peritoneal macrophages stimulated by necrotic cell or lipopolysaccharide. In conclusion, mefunidone serves as a novel anti-inflammatory agent that attenuates UUO-induced renal interstitial inflammation and fibrosis, possibly through suppressing IKKβ phosphorylation.