TDP-43 maintains chondrocyte homeostasis and alleviates cartilage degradation in osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is the most prevalent age-related disorder due to cartilage degradation. Previous studies have identified aberrant chondrocyte homeostasis under extracellular stress as a key pathological mechanism behind cartilage degradation in OA. TDP-43, a DNA/RNA-binding protein has been demonstrated to participate in processing many extracellular stress responses; however, understanding of the role of TDP-43 in OA is limited. This study aims to investigate the role of TDP-43 in chondrocyte homeostasis and cartilage degradation in OA.

METHODS

The role of TDP-43 during degradation of cartilage is examined by experimental posttraumatic OA animal models and human cartilage specimens. Cartilage degradation is assessed by histological analysis, qPCR, and Western blot. The molecular mechanisms are investigated in vitro using human primary chondrocytes.

RESULTS

TDP-43 decreases significantly in degenerated cartilage. TDP-43 concentration is positively correlated with IL-1β concentration in synovial fluid derived from OA patients (Pearson r = 0.95, CI (95%) [0.80, 0.99], P < 0.0001). Intra-articular injection of recombinant TDP-43 significantly alleviates cartilage degradation and subchondral bone remodeling in vivo. In vitro mechanistic analyses show that TDP-43 maintains chondrocyte homeostasis under oxidative stress through regulating stress granule dynamics via G3BP1.

CONCLUSION

The present study indicates that TDP-43 maintains chondrocyte homeostasis under oxidative stress and alleviates cartilage degeneration in osteoarthritis, identifying TDP-43 as a potential target for the diagnosis and treatment of knee OA.

CNN-based qualitative detection of bone mineral density via diagnostic CT slices for osteoporosis screening

The features extracted from diagnostic computed tomography (CT) slices were used to qualitatively detect bone mineral density (BMD) through neural network models, and the evaluation results indicated that it may be a promising approach to perform osteoporosis screening in clinical practice.

INTRODUCTION

The purpose of this study is to design a novelty diagnostic method for osteoporosis screening by using the convolutional neural network (CNN), which can be incorporated into the procedure of routine CT diagnostic in medical examination thereby improving the osteoporosis diagnosis and reducing the patient burden.

METHODS

The proposed CNN-based method mainly comprises two functional modules to perform qualitative detection of BMD by analyzing the diagnostic 2D CT slice. The first functional module aims to locate and segment the ROI of diagnostic 2D CT slice, called Mark-Segmentation-Network (MS-Net). The second functional module is used to determine the category of BMD by the features of ROI, called BMD-Classification-Network (BMDC-Net). The diagnostic 2D CT slice of pedicle level in lumbar vertebrae (L1) was selected from 3D CT image in our experiments firstly. Then, the trained MS-Net can get the mark image of input original 2D CT slice, thereby obtain the segmentation image. Finally, the trained BMDC-Net can obtain the probability value of normal bone mass, low bone mass, and osteoporosis by inputting the segmentation image. On the basis of network results, the radiologists can provide preliminary qualitative diagnosis results of BMD.

RESULTS

Training of the network was performed on diagnostic 2D CT slices of 150 patients. The network was tested on 63 patients. Each patient corresponds to a 2D CT slice. The proposed MS-Net has an excellent segmentation precision on the shape preservation of different lumbar vertebra. The dice index (DI), pixel accuracy (PA), and intersection over union (IOU) of segmentation results are greater than 0.8. The proposed BMDC-Net achieved an accuracy of 76.65% and an area under the receiver operating characteristic curve of 0.9167.

CONCLUSIONS

This study proposed a novel method for qualitative detection of BMD via diagnostic CT slices and it has great potential in clinical applications for osteoporosis screening. The method can potentially reduce the manual burden to radiologists and diagnostic cost to patients.

[Interaction analysis between epidermal growth factor and peroxidase proliferators activate receptor-α gene polymorphism and susceptibility to generalized aggressive periodontitis]

Objective: To explore the correlation and interaction between epidermal growth factor (EGF) rs2237051 and peroxidase proliferators activate receptor-α (PPAR-α) rs4253623 polymorphisms and the susceptibility of generalized aggressive periodontitis (GAgP). Methods: Two hundred and nineteen Chinese patients with GAgP were enrolled from the patients of the Department of Periodontology, Peking University School and Hospital of Stomatology from January 2001 to December 2015. The control group comprised 138 periodontally healthy volunteers recruited from the staff and students of the Peking University School and Hospital of Stomatology. The EGF rs2237051 and PPAR-α rs4253623 polymorphisms were genotyped using time-of-flight mass spectrometry. Logistic regression models were conducted to analyze the correlation between the EGF rs2237051 and PPAR-α rs4253623 variants with GAgP. The likelihood ratio test was used to analyze whether there was an interaction between the two polymorphisms in the susceptibility of GAgP. The interaction model adopted was the multiplication model. Results: The mean ages of GAgP group (male:87; female:132) and control group (male: 53; female: 85) were (27.3±4.5) years and (27.1±4.2) years respectively and there was no significant difference in age and gender distribution between the two groups. For EGF rs2237051, the frequency of AA genotype in the GAgP group [49.5% (107/216)] was significantly higher than that in the control group [37.7% (52/138)], and the frequency of AG/GG genotype in the GAgP group [50.5% (109/216)] was significantly lower than that in the control group [62.3% (86/138)](P<0.05). Compared with AA genotype, individuals with AG/GG genotype had a 39% lower risk of GAgP after adjustment of age and gender (OR: 0.61, 95%CI: 0.40-0.95, P<0.05). For PPAR-α rs4253623, the frequency of AA genotype in the GAgP group [76.2% (160/210)] was significantly higher than that in the control group [65.9%(81/123)], and the frequency of AG/GG genotype in the GAgP group [23.8% (50/210)] was significantly lower than that in the control group [34.1%(42/123)] (P<0.05). Compared with AA genotype, individuals with AG/GG genotype had a 40% lower risk of GAgP after adjustment of age and gender (OR: 0.60, 95%CI: 0.36-0.98, P<0.05). EGF rs2237051 and PPAR-α rs4253623 showed a significant interaction in the susceptibility to GAgP. Compared with AA genotype, the risk of GAgP in individuals with both AG/GG genotypes of EGF rs2237051 and PPAR-α rs4253623 was reduced by 66% (OR: 0.34, 95%CI: 0.17-0.66, P<0.01). Conclusions: EGF rs2237051 and PPAR-α rs4253623 are correlated with GAgP susceptibility, and there is a significant interaction between them in the susceptibility of GAgP. The G allele of the two loci has a protective effect on the disease of GAgP.

Detection of hepatitis E virus genotypes 3 and 4 in donkeys in northern China

BACKGROUND

Hepatitis E virus (HEV) is the causative agent of acute self-limiting hepatitis in humans in developing countries. Hepatitis E virus RNA was first detected in donkeys in Spain, but little is known about the possible presence of HEV in donkeys in China.

OBJECTIVES

To investigate the prevalence of HEV in donkeys in northern China.

STUDY DESIGN

Investigation of the prevalence of HEV in donkeys using serological, molecular and phylogenetic approaches.

METHODS

A total of 401 donkey serum specimens were tested for serological and molecular detection of HEV via enzyme-linked immunosorbent assay and quantitative reverse transcription polymerase chain reaction. The amplified products were cloned in pMD18-T vector and sequenced. The alignment and phylogenetic analysis of partial HEV ORF2 genes were compared with the corresponding sequences of the obtained HEV representative strains.

RESULTS

Serological results showed that 49 donkeys (12.22%, 95% CI: 9.18-15.83%) were positive for anti-HEV-specific antibodies, and 17 donkeys (4.24%, 95% CI: 2.49-6.70%) were positive for HEV viral RNA. On the basis of sequence alignment and phylogenetic analysis, all isolated HEV strains belonged to genotype 3 (HEV-3) or HEV-4, sharing more than 76.2-96.3% identities with 67 other HEV representative strains of HEV-1 to HEV-8.

MAIN LIMITATIONS

Further studies about the prevalence of HEV in organs or faecal samples from donkeys are needed to evaluate the possible role of HEV reservoir and to determine the risk factors associated with the transmission of this zoonotic virus in donkeys in China.

CONCLUSIONS

This is the first report documenting the molecular analysis of donkey HEV strains worldwide and the serological evidence of HEV infection in donkeys in northern China. The results suggest that young donkeys are more susceptible to HEV infection compared with older donkeys. Further investigation is required to determine whether donkeys should be considered reservoirs for zoonotic HEV. The Summary is available in Chinese - see Supporting information.

A study of dynamic contrast-enhanced MR imaging features and influence factors of pelvic bone marrow in adult females

Perfusion of the pelvic bone marrow is reduced in the postmenopausal group and with age. Quantitative dynamic contrast-enhanced MRI could reflect the blood supply characteristics and hemodynamic changes of the pelvic bone marrow. These results contribute to the description of osteoporosis in the postmenopausal females and the elderly.

INTRODUCTION

To investigate the effect of menstrual status and age on the perfusion of pelvic bone marrow in adult females using quantitative dynamic contrast-enhanced MRI (DCE-MRI).

METHODS

In total, 96 adult females who underwent DCE-MRI between September 2017 and December 2017 were included. All the subjects' quantitative DCE-MRI parameters of pelvic bone marrow were measured and retrospectively analyzed, including K^trans (volume transfer constant), K_ep (efflux rate constant), and V_e (interstitial volume). According to their menstrual status, the subjects were divided into a premenopausal group (n = 39) and a postmenopausal group (n = 57), and the two groups were then divided into four subgroups according to age. The intraobserver reliability was assessed by the intraclass correlation coefficient (ICC). The parameters were compared between different menstrual status groups and age subgroups by Mann-Whitney test, and Spearman correlation analysis was used to evaluate the correlation between the age and the quantitative parameters.

RESULTS

The ICCs of the K^trans, K_ep, and V_e values were 0.989, 0.974, and 0.920, respectively. K^trans, K_ep, and V_e of the premenopausal group were significantly higher than those of the postmenopausal group (P < 0.05). The overall age was negatively correlated with K^trans, K_ep, and V_e (r = - 0.590, - 0.357, and - 0.381, respectively, P < 0.05). In the premenopausal group, K^trans and V_e were significantly higher in subgroup 1 (≤ 40 years) compared with subgroup 2 (> 40 years) (P < 0.05), and age showed a negative correlation with K^trans and V_e (r = - 0.344 and - 0.334, respectively, P < 0.05). In the postmenopausal group, K^trans and K_ep were significantly higher in subgroup 3 (≤ 60 years) compared with subgroup 4 (> 60 years) (P < 0.05), and age showed a negative correlation with K^trans and K_ep (r = - 0.460 and - 0.303, respectively, P < 0.05).

CONCLUSION

Menstrual status and age have significant effects on the perfusion of the pelvic bone marrow microenvironment in adult females and that the microenvironment of the pelvic bone marrow displays different changes at different age stages. Quantitative DCE-MRI has contributed to the interpretation of the pelvic bone marrow perfusion status.

[Prospective study of relationship between metabolic diseases and stroke in Jinchang Cohort]

Objective: To understand the incidence of stroke in the population of Jinchang Cohort and the relationship between metabolic diseases and stroke, and provide scientific evidence for the prevention and treatment of stroke in the population. Methods: The epidemiological investigation data and physical examination data of the 33 042 follow-up participants in Jinchang Cohort were collected for a prospective cohort study. Restricted cubic splines functions was used to analyze the dose-response relationship between metabolic indexes and the risk of stroke incidence. Results: 1) The incidence rate of stroke in Jinchang Cohort was 1.59%, and the standardized incidence rate was 3.99%. 2) Hypertension (male HR=2.20, female HR=4.45) and dyslipidemia (male HR=1.49, female HR=1.79) were the risk factors of stroke incidence in the population and diabetes had influence on the incidence of stroke only in the males (HR=1.79), while obesity had influence only in the females (HR=1.64). The more kinds of metabolic diseases, the higher risk of stroke incidence was. 3) Systolic blood pressure had a non-linear dose-response correlation with the risk of stroke incidence, while diastolic blood pressure had a positive linear correlation with the risk of stroke incidence. Conclusions: The incidence of stroke in Jinchang Cohort population was high compared with both domestic level and oversea level. The patients with metabolic diseases were the population at high-risk for stroke, and more attention should be paid to them in the prevention and treatment of stroke. Diastolic blood pressure might be more closely related to stroke.

Body Size Influences Stingless Bee (Hymenoptera: Apidae) Communities Across a Range of Deforestation Levels in Rondônia, Brazil

Developments in understanding bee responses to habitat loss indicate that body size is a trait with important consequences for conservation. Stingless bees (Hymenoptera, Apidae, Meliponini) are a diverse group of eusocial bees providing pollination services in tropical landscapes, exhibiting a large range in body size across species. We tested the effects of deforestation on the body sizes of stingless bee communities by using museum specimens and revisiting a previous effort that sampled stingless bee communities across varying levels of deforestation at 183 sites in Rondônia, Brazil, in 1996-1997. Body size measurements (intertegular distance) from 72 species collected were included as dependent variables in response to forest area, forest edge, and connectivity of forest patches at several spatial scales. We find that stingless bee body size is negatively related to forest cover: mean community body size was larger in areas with greater amounts of deforestation, and smaller in areas with less deforestation. Second, stingless bee species richness was positively associated with forest edge regardless of body size. Lastly, we find that as forest patch isolation increased, the stingless bee community body size also increased. These findings support hypotheses that small stingless bee species might be more negatively affected by deforestation, adding to the growing body of evidence that stingless bees require areas of intact forest in near proximity to other forest patches to conserve these diverse pollinator communities.

[Clinical study of locking-taper implants in patients treated for periodontitis]

OBJECTIVE

To evaluate the survival rate and peri-implant clinical parameters of Locking-Taper implants in patients having lost their teeth due to non-periodontitis (NP) reasons, chronic periodontitis (CP) and aggressive periodontitis (AgP).

METHODS

In the study, 145 subjects were installed with 315 Bicon Locking-Taper implants and followed up for 1-5 years. The subjects and implants were classified into three groups, tooth loss by NP, CP and AgP. NP included 44 subjects with 100 implants, CP 70 subjects with 132 implants and AgP 31 subjects with 83 implants. Periodontal parameters before subgingival scaling and root planning (T0), at the end of active periodontal therapy (T1) and at the time of last recall (T2) were recorded. Right after the installation of final restoration and at the time of last recall (T2), peri-implant probing parameters were recorded.

RESULTS

After active periodontal therapy, mean probing depth (PD) in CP and AgP were reduced from 4.05 mm, 5.20 mm at T0 to 3.07 mm, 2.96 mm at T1 (P<0.001, P<0.001), (PD≥6 mm)% were reduced from 33.2%, 58.5% at T0 to 14.4%, 10.5% at T1 (P<0.001, P<0.001). The periodontal parameters remained stable at T2 compared with T1 (P>0.05). Cumulative survival rates of implants in NP, CP and AgP were 100%, 97.6% and 100% for 1-5 years' follow-ups with no statistical significance found. At T2, mean implant PD was 2.78 mm, 2.96 mm and 2.97 mm in NP, CP and AgP, with NP significantly lower than the other two groups (P=0.006, P=0.01). The percentage of implant sites with PD≥6 mm was 3.7% in CP and 4.8% in AgP, both significantly higher than NP (P=0.003, P<0.001). 8.4% implant sites showed at least 2 mm deeper than those at prosthesis installation were found in CP group, significantly higher than NP (4.3%, P=0.003).

CONCLUSION

Periodontal conditions of patients having lost their teeth for chronic and aggressive periodontitis were significantly improved after active periodontal therapy and remained stable during 1-5 years. Short-term survival rates of Locking-Taper implants in patients treated for CP and AgP was no less than those who lost their teeth for non-periodontitis reasons. More sites with increasing peri-implant probing depth were found in CP and AgP patients, compared with NP.

[Applied research of "quadri-low" combined with automatic tube current modulation and iterative model reconstruction technology in head and neck CT angiography]

Objective: To investigate the feasibility of low tube voltage, low contrast medium concentration, injection rate and volume (quadri-low) combined with automatic tube current modulation (ATCM) and iterative model reconstruction (IMR) technology in head and neck CT angiography (CTA). Methods: A total of 70 patients whose body mass index (BMI)<25 kg/m(2) underwent head and neck CTA and digital subtraction angiography (DSA) from January to July 2017 were enrolled in this prospective study. According to random number table, patients were divided into two groups: group A (n=35) was scanned according to the protocol of 120 kV, 150 mAs, 50 ml and 5 ml/s iopromide (370 mg/ml) and filtered back projection (FBP) reconstruction; group B (n=35) was scanned with 80 kV, ATCM with mean tube current of 100 mAs, 30 ml and 3 ml/s iohexol (300 mg/ml) and IMR; the other parameters kept consistent between the two groups. The maximum transverse neck diameter at the level of the hyoid bone, artery CT value and image noise were measured, signal to noise ratio (SNR), contrast to noise ratio (CNR) and figure of merit (FOM) were calculated, and the image quality was evaluated subjectively and compared with those reconstructed by DSA. Scan length, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded, and the effective dose (ED) was calculated. The chi-square and independent-sample t tests were used to compare the inter-group differences in these aforementioned data. Resutls: No significant difference was found in general information between the two groups. No significant difference existed in artery CT value, image noise, SNR and CNR between the two groups (t=-1.170-1.365, all P>0.05); however, the FOM of group B (74±40) was significantly higher than that in group A (12±4) (Z=-7.195, P=0.000). The image quality of the two groups met the requirement of clinical diagnosis[(4.1±0.7) vs (4.2±0.8) points, Z=-0.592, P>0.05], no significant difference was found in subjective evaluation and diagnostic efficacy. The CTDIvol, DLP and ED in group B were all significantly lower than those in group A (Z=-7.728, -7.202, -7.206, all P<0.05). The iodine load and iodine delivery rate (IDR) of group B was lower than that of group A (18.5 g vs 9.0 g, 1.85 mg/s vs 0.90 mg/s), and they were reduced for 51.4% in group B. Conclusions: For patients of BMI <25 kg/m(2,) low tube voltage, low contrast medium concentration, injection rate and volume combined with ATCM and IMR technology can significantly decrease radiation dose, iodine load and IDR while maintain the image quality in head and neck CTA examination.

A G3P[13] porcine group A rotavirus emerging in China is a reassortant and a natural recombinant in the VP4 gene

Group A rotaviruses (RVAs) are a major cause of serious intestinal disease in piglets. In this study, a novel pig strain was identified in a stool sample from China. The strain was designated RVA/Pig/China/LNCY/2016/G3P[13] and had a G3-P[13]-I5-R1-C1-M1-A8-N1-T1-E1-H1 genome. The viral protein 7 (VP7) and non-structural protein 4 (NSP4) genes of RVA/Pig/China/LNCY/2016/G3P[13] were closely related to cogent genes of human RVAs, suggesting that a reassortment between pig and human strains had occurred. Recombination analysis showed that RVA/Pig/China/LNCY/2016/G3P[13] is a natural recombinant strain between the P[23] and P[7] RVA strains, and crossover points for recombination were found at nucleotides (nt) 456 and 804 of the VP4 gene. Elucidating the biological characteristics of porcine rotavirus (PoRV) will be helpful for further analyses of the epidemic characteristics of this virus. The results of this study provide valuable information for RVA recombination and evolution and will facilitate future investigations into the molecular pathogenesis of RVAs.

DNA methylation and expression of imprinted genes are associated with the viability of different sexual cloned buffaloes

The DNA methylation of imprinted genes is an important way to regulate epigenetic reprogramming of donor cells in somatic cell nuclear transfer (SCNT). However, the effects of sexual distinction on the DNA methylation of imprinted genes in cloned animals have seldom been reported. In this study, we analysed the DNA methylation status of three imprinted genes (Xist, IGF2 and H19) from liveborn cloned buffaloes (L group, three female and three male), stillborn cloned buffaloes (S group, three female and three male) and natural reproduction buffaloes (N group, three female and three male), using bisulphite sequencing polymerase chain reaction (BS-PCR). The expression levels of these imprinted genes were also investigated by quantitative real-time PCR (QRT-PCR). The DNA methylation levels of H19 were not significantly different among the groups. However, the Xist in female and IGF2 in male of the S group were found to be significantly hypomethylated in comparison with the same sexual buffaloes in L group and N group (p < .05). Furthermore, the expression levels of Xist, IGF2 and H19 in the stillborn female cloned buffaloes of S group were significantly higher than that of the female buffaloes in the L group and N group (p < .05). The expression levels of IGF2 and H19 in the stillborn male cloned buffaloes in the S group were significantly higher than that of the male buffaloes in the L group and N group (p < .05). These results indicate that Xist may be associated with the viability of female cloned buffaloes, and IGF2 may also be related to the viability of male cloned buffaloes.

Feasibility study of iterative model reconstruction combined with low tube voltage, low iodine load, and low iodine delivery rate in craniocervical CT angiography

AIM

To investigate the feasibility of iterative model reconstruction (IMR) combined with low tube voltage, low iodine load, and low iodine deliver rate in craniocervical computed tomography angiography (CTA).

MATERIALS AND METHODS

Sixty patients were randomly divided into two groups (n=30 for each): group A: 120 kVp, 50 ml of iopromide at a flow rate of 5 ml/s; filtered back projection (FBP) reconstruction; group B: 80 kVp, 30 ml of iohexol at 4.5 ml/s; hybrid iterative reconstruction (HIR) for group B1 and IMR for group B2. CT attenuation values, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective image quality, effective dose (ED), iodine load, and iodine delivery rate (IDR) were compared.

RESULTS

CT attenuation values of the arteries were higher in groups B1 and B2 than group A. The SNR and CNR were higher, while image noise was lower, for group B2 compared with groups B1 and A. The best subjective image quality was obtained with group B2. ED, iodine load, and IDR reduction of 69.6%, 51.4%, 27%, respectively, was obtained in group B compared with group A.

CONCLUSION

IMR combined with 80 kVp and 30 ml of iohexol at a flow rate of 4.5 ml/s for craniocervical CTA can reduce ED, iodine load, and IDR, while improving image quality.

Enhanced blood brain barrier permeability and glioblastoma cell targeting via thermoresponsive lipid nanoparticles

Thermoresponsive targeting is used to deliver therapeutic agents at hyperthermic conditions (39-45 °C). However, available thermoresponsive drug delivery systems (TDDS), including liposomes, have a complex method of preparation involving toxic solvents and reagents. The objective of this in vitro study was to prepare and characterize thermoresponsive lipid nanoparticles (TLN) for treating glioblastoma, the most aggressive brain tumor whose treatment is limited by a low blood brain barrier (BBB) permeability of drugs. Thermoresponsive lipids were prepared by mixing liquid and solid fatty acids (0.1 : 1 to 2 : 1 ratio) and lipid mixtures exhibiting a solid-liquid phase transition at 39 °C were identified by plotting melting point against liquid contents. TLN were prepared by a hot melt encapsulation method using mono- or double-surfactant systems. TLN showed desirable size (<270 nm), zeta potential (-35 to -50 mV), spherical morphology and stability by FTIR studies. In the drug release studies, paclitaxel release was slow at 37 °C, however, it was released abruptly at 39 °C due to the faster diffusion rate from liquid state nanoparticles. During cytotoxicity studies, the unloaded TLN were non-toxic whereas paclitaxel loaded TLN showed higher cytotoxicity to glioblastoma cells at 39 °C (69% cell viability after one hour) compared to 37 °C (82% cell viability). The TLN showed higher permeability across an in vitro model of BBB at 39 °C due to a deformable liquid state which can squeeze through the tight junctions of the BBB. In conclusion, this study demonstrated that the TLN can be used as a safe and effective alternative to traditional TDDS with higher potential to target glioblastoma cells across the BBB.

FTY720 ameliorates renal fibrosis by simultaneously affecting leucocyte recruitment and TGF-β signalling in fibroblasts

Renal fibrosis is the common final manifestation of chronic kidney diseases and usually results in end-stage renal failure. In this study, we evaluated the effect of fingolimod (FTY720), an analogue of sphingosine 1-phosphate (S1P), as a treatment for the unilateral ureteral obstruction (UUO)-induced renal fibrosis animal model. We treated mice with FTY720 at a dosage of 1 mg/kg/day by intragastric administration from day 1 until day 7. The control group received the same amount of saline. FTY720 reduced significantly the urine albumin/creatinine ratio (UACR) in treated UUO mice. FTY720 treatment also caused a significant decrease in interstitial expansion and collagen deposition in the kidney, accompanied by reduced mononuclear cell recruitment and inflammatory cytokine expression. In addition, the expression levels of the endothelial cell adhesion molecules P-selectin and vascular cell adhesion protein 1 (VCAM-1) were suppressed in the ligated kidney by FTY720 administration, suggesting reduced renal endothelial cell activation. Furthermore, in renal interstitial fibroblast normal rat kidney (NRK)-49F cells, FTY720 significantly affected transforming growth factor (TGF)-β-induced α-smooth muscle actin (SMA) expression and collagen synthesis by inhibiting both the Mothers against decapentaplegic homologue (Smad)2/3 and phosphatidylinositol 3-kinase/protein kinase B/glycogen synthase kinase 3 beta (PI3K/AKT/GSK3β) signalling pathways. S1P1 knock-down by siRNA reversed this effect significantly in our fibroblast cell culture model. Therefore, FTY720 attenuates renal fibrosis via two different mechanisms: first, FTY720 suppresses the synthesis of extracellular matrix in interstitial fibroblasts by interfering with TGF-β signalling; and secondly, FTY720 affects endothelial cell activation and chemokine expression, thereby reducing immune cell recruitment into the kidney.