Protective effects of SIRT1 in patients with proliferative diabetic retinopathy via the inhibition of IL-17 expression

  • Authors:
    • Shulin Liu
    • Yu Lin
    • Xin Liu
  • View Affiliations

  • Published online on: November 18, 2015     https://doi.org/10.3892/etm.2015.2877
  • Pages: 257-262
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Abstract

Diabetic retinopathy (DR) is a chronic microvascular complication of diabetes that may lead to loss of vision. The pathogenesis of DR is complex and elevated expression levels of T helper (Th)17 cells and interleukin (IL)‑17 have been suggested to be associated with the development and progression of DR. Sirtuin 1 (SIRT1) is a nicotinamide‑adenine dinucleotide+‑dependent histone deacetylase that is downregulated in patients with DR. Previous studies have demonstrated that SIRT1 is capable of inhibiting the production of IL‑17. In the present study, 19 patients with proliferative diabetic retinopathy (PDR) and 20 non‑diabetic controls with idiopathic macular epiretinal membranes were recruited and the SIRT1 expression levels of excised specimens were analyzed using immunohistochemistry. IL‑17 expression levels in the sera from patients with PDR and controls were determined by enzyme‑linked immunosorbent assay (ELISA). Furthermore, SIRT1 mRNA and protein expression levels in peripheral blood mononuclear cells (PBMCs) from the two groups were analyzed following culture with or without a SIRT1 activator, resveratrol. IL‑17 expression levels in the supernatants of PBMCs were determined using ELISA and the results demonstrated that IL‑17 expression levels were increased in the sera of patients with PDR, as compared with the controls. Furthermore, increased expression levels of SIRT1 and IL‑17 were detected in fibrovascular membranes and PBMCs harvested from patients with PDR, respectively. Notably, SIRT1 mRNA and protein expression levels were decreased in the PBMCs of patients with PDR and IL‑17 production was inhibited following SIRT1 activation. The results of the present study indicated that imbalanced IL‑17 and SIRT1 expression levels may contribute to the pathogenesis of DR, and SIRT1 may have a protective role in PDR by inhibiting the production of IL-17.

Introduction

Diabetic retinopathy (DR) is a sight-threatening, chronic microvascular complication of diabetes. DR, which accounts for 5% of all blindness, affects ~5 million patients worldwide and is characterized by the progressive occlusion of capillaries, leading to retinal nonperfusion and ischemia (1). In an ischemic retina, the induction of vascular endothelial growth factor (VEGF) expression mediates the pathological intraocular proliferation of vessels which characterizes proliferative diabetic retinopathy (PDR) (2). The majority of diabetic patients develop varying degrees of retinopathy by 20 years of disease duration (3). In 2012, there were ~93 million cases of DR globally, 17 million of which were PDR (4). The pathogenesis of DR is complex, including inflammation (5), oxidative stress (6) and advanced glycation end products (AGEs) (7). Previous studies have suggested that chronic inflammation and the immune response promote the development of DR. T helper (Th)17 cells and interleukin (IL)-17 participate in the immune response and are associated with the development and progression of DR (8,9); however, this remains controversial as previous studies have demonstrated a positive association between IL-17 and DR (8,10), whereas others have demonstrated a negative association (912).

Sirtuin 1 (SIRT1) is a nicotinamide-adenine dinucleotide (NAD)+-dependent histone deacetylase associated with various fundamental physiological processes, including oxidative stress, glucose metabolism, DNA stability, aging and tumorigenesis (1315). Previous studies have demonstrated that SIRT1 may be associated with the pathogenesis of DR (16,17); however, the underlying mechanisms are yet to be elucidated. Furthermore, as previous studies have stated that SIRT1 is capable of modulating the production of IL-17 (18,19), the authors of the present study hypothesized that SIRT1 functions through the regulation of IL-17 in patients with DR. In order to test this hypothesis, the present study aimed to evaluate the expression levels of SIRT1 in the retinal fibrovascular membranes and peripheral blood mononuclear cells (PBMCs) of patients with DR and analyze the potential association between SIRT1 expression and serum IL-17 expression levels.

Materials and methods

Patients

A total of 19 patients with PDR were recruited for the present study between April 2014 and August 2014. All of the patients had previously been diagnosed with type 2 diabetes (T2D), according to the World Health Organization (WHO) criteria (20). A total of 20 patients without diabetes who presented with idiopathic macular epiretinal membranes whilst waiting for vitrectomy were recruited as control subjects. The present study was approved by the Clinical Research Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (Chongqing, China) and followed the tenets of the Declaration of Helsinki. Informed consent was acquired from all participants and detailed demographics of the patients are outlined in Table I.

Table I.

Characteristics of subjects.

Table I.

Characteristics of subjects.

CharacteristicsTotalPatients with PDRControl subjects
Number391920
Gender (male/female)18/2110/98/12
Average age (years)59.565.8
Average duration of type 2 diabetes (years)14

[i] PDR, proliferative diabetic retinopathy.

Immunohistochemistry

Vitrectomy was performed on all the participants. Fibrovascular membrane samples from patients with PDR and epiretinal membrane samples from the controls were excised during the surgery, fixed in 4% paraformaldehyde, embedded in paraffin, and cut into 5-µm sections. Briefly, 10% goat serum (Beyotime Institute of Biotechnology, Haimen, China) was used to block nonspecific binding, and the slides were incubated overnight with mouse monoclonal SIRT1 primary antibody (1:200; sc-74504; Santa Cruz Biotechnology, Inc., Dallas, TX, USA). After washing three times with Tris-buffered saline, biotinylated secondary antibody (1:150; Santa Cruz Biotechnology, Inc.) was subsequently applied for 20 min at room temperature and the sections were visualized using a StrepABC horseradish peroxidase kit (Beyotime Institute of Biotechnology). Subsequently, goat anti-mouse biotinylated secondary antibody (1:150; sc-2039; Santa Cruz Biotechnology, Inc.) was applied for 20 min at room temperature and the sections were visualized using a StrepABC horseradish peroxidase kit (Beyotime Institute of Biotechnology). SIRT1 expression levels were semiquantitatively measured using a light microscope (magnification, ×200; BX51T-PHD-J11; Olympus Corporation, Tokyo, Japan), to generate an immunoreactive score (IRS) (21). Negative expression was defined by an IRS score of 0, low expression levels were defined by an IRS score of 1–5, whereas high expression was denoted by an IRS score of 6–12.

Circulating IL-17 measurements

Circulating expression levels of IL-17 in the sera of patients with PDR and the controls were determined using enzyme-linked immunosorbent assay (ELISA; R&D Systems, Inc., Minneapolis, MN, USA), according to the manufacturer's protocol.

PBMC culture

PBMC culture was performed as previously described (22). Briefly, fasting blood samples were harvested from all participants using Vacutainer® tubes supplemented with heparin (BD Biosciences, Franklin Lakes, NJ, USA). PBMCs were obtained using Ficoll-Hypaque™ density gradient centrifugation (GE Healthcare, Piscataway, NJ, USA). PBMCs were cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin (all Invitrogen, Carlsbad, CA, USA), and incubated at 37°C in an atmosphere containing 5% CO2 for 24 h. Subsequently, 1×106 PBMCs/ml were cultured on 24-well plates and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) or western blotting was used to determine the mRNA and protein expression levels of SIRT1, respectively. In order to ascertain the effects of an SIRT1 activator, resveratrol, on the expression levels of IL-17, anti-CD3 (5 µg/ml; 11-0039-41; eBioscience, Inc., San Diego, CA, USA) and anti-CD28 (1 µg/ml; 11-0289-41; eBioscience, Inc.) mouse monoclonal antibodies were added with/without 10 µM resveratrol (Sigma-Aldrich, St. Louis, MO, USA) (23). Resveratrol was stored as a powder and sterile phosphate-buffered saline solution (PBS) was added to the powder prior to use. Following 72 h incubation, the expression levels of IL-17 in the supernatants of the PBMCs were analyzed using ELISA (R&D Systems, Inc.). The mRNA and protein expression levels of SIRT1 in the PBMCs from the patients and controls were analyzed again using the methods described below. All experiments were repeated in triplicate.

RNA extraction and RT-qPCR

An RNeasy Mini kit (Qiagen GmbH, Hilden, Germany) was used to extract the total RNA from PBMCs, according to the manufacturer's protocol. cDNA was synthesized from 1 µg total RNA using a TaqMan® Reverse Transcription kit (Applied Biosystems; Thermo Fisher Scientific, Inc., Foster City, CA, USA), according to the manufacturer's protocol. RT-qPCR was subsequently performed on an ABI 7500 Real-Time PCR system (Applied Biosystems; Thermo Fisher Scientific) using SYBR® Premix Ex Taq™ II (Takara Bio, Inc., Otsu, Japan). The following primer sequences were used: β-actin, forward 5′-GGATGCAGAAGGAGATCACTG-3′ and reverse 5′-CGATCCACACGGAGTACTTG-3′; and SIRT1, forward 5′-CGGAAACATACCTCCACCTGA-3′ and reverse 5′-GAAGTCTACAGCAAGGCGAGCA-3′. The following cycling conditions were used: One cycle at 95°C for 3 min, and 40 cycles of 95°C for 3 sec and 58°C for 20 sec, followed by 1 cycle of 95°C for 15 sec, 60°C for 15 sec and 95°C for 15 sec. SIRT1 expression levels were normalized to the expression levels of a housekeeping gene, β-actin. Fold change was calculated using the 2−ΔΔCq method (24).

Nuclear protein extraction and western blotting

PBMCs were washed twice with ice-cold PBS and NE-PER™ Nuclear Extraction reagents (Pierce Biotechnology, Inc., Rockford, IL, USA) were used to extract PBMC nuclear proteins, according to the manufacturer's protocol. Nuclear proteins were subsequently boiled for 10 min with 5% sodium dodecyl sulfate (SDS) loading buffer (4:1), separated by 8% SDS-polyacrylamide gel electrophoresis and transferred to a polyvinylidene difluoride (PVDF; EMD Millipore, Billerica, MA, USA) membrane. The membrane was blocked using 5% non-fat milk and rabbit monoclonal anti-SIRT1 (1:2,000; #2496; Cell Signaling Technology, Inc., Danvers, MA, USA) primary antibody was added to the membrane and incubated for 1 h at room temperature. The membrane was subsequently washed using PBS and alkaline phosphatase (ALP) buffer (Beyotime Institute of Biotechnology) containing 100 mmol/l Tris-HCl prior to incubation with ALP-conjugated secondary antibody (1:7,500; #7054; Cell Signaling Technology, Inc., Danvers, MA, USA) for 1 h at room temperature. Following this, 10 ml ALP buffer, 66 µl 5-bromo-4-chloro-3-indolyl phosphate (Beyotime Institute of Biotechnology) and 33 µl nitro blue tetrazolium chloride (Beyotime Institute of Biotechnology) were mixed, added to the membrane and incubated at 37°C. ddH2O was added once the protein bands were clear and ImageJ software, version 1.43 (National Institutes of Health, Bethesda, MA, USA) was used to quantify the protein levels. β-actin housekeeping protein was used for normalization.

Statistical analysis

One-way analysis of variance was used to compare the expression levels of IL-17 in the supernatants of the PBMCs and the mRNA and protein expression levels of SIRT1 in PBMCs. Between-group differences were determined using Tukey's test. Student's t-test was used to compare the expression levels of IL-17 in the sera of the control and PDR groups, whereas χ2 test was used to compare the differences in SIRT1 expression levels in the excised membranes from the controls and patients with PDR. Statistical tests were performed using GraphPad Prism® 5 (GraphPad Software, Inc., La Jolla, CA, USA) or SPSS software (SPSS, Inc., Chicago, IL, USA). Data are expressed as the mean ± standard deviation. P<0.05 was considered to indicate a statistically significant difference.

Results

Increased SIRT1 expression levels in fibrovascular membranes from patients with PDR

The expression levels of SIRT1 in fibrovascular (n=19) and epiretinal membranes (n=20) were examined using immunohistochemical analysis (Fig. 1; Table II). A significant difference in the expression levels of SIRT1 was demonstrated between the two groups (χ2=23.85, P <0.001).

Table II.

Sirtuin 1 (SIRT1) expression levels in samples excised from patients with proliferative diabetic retinopathy (PDR) and non-diabetic control subjects.

Table II.

Sirtuin 1 (SIRT1) expression levels in samples excised from patients with proliferative diabetic retinopathy (PDR) and non-diabetic control subjects.

SIRT1 expression levels

SampleCaseNegativeLowHighχ2P-value
Fibrovascular membranes from patients with PDR19  251223.85<0.001
Epiretinal membranes from control subjects20163  1
IL-17 expression levels increase in the sera and PBMC supernatants of patients with PDR

IL-17 expression levels were significantly increased in the sera from patients with PDR (21.4±5.9 pg/ml), as compared with the control group (17.3±6.2 pg/ml; P=0.038; Fig. 2). Furthermore, the expression levels of IL-17 in the supernatants of cultured PBMCs were significantly increased in patients with PDR (419.3±53.7 pg/ml), as compared with the control group (182.5±50.3 pg/ml; P<0.05; Fig. 3).

SIRT1 mRNA and protein expression levels decrease in patients with PDR

The mRNA expression levels of SIRT1 in the PBMCs of patients with PDR were significantly reduced, as compared with the control group (0.54±0.08 vs. 1.24±0.08; P<0.05; Fig. 4). The protein expression levels of SIRT1 were consistent with these mRNA results. In the PBMCs of patients with PDR that did not receive resveratrol stimulation, SIRT1 protein expression levels were significantly reduced, as compared with those from control subjects (0.11±0.01 vs. 0.19±0.03; P<0.05; Fig. 5).

SIRT1 activation inhibits IL-17 production by PBMCs in patients with PDR

In order to explore the effects of resveratrol on the expression levels of IL-17 in PBMCs, PBMCs were incubated with anti-CD3, anti-CD28 and 10 µM resveratrol for 72 h, and the mRNA and protein expression levels of SIRT1 were subsequently determined. The results demonstrated that resveratrol activated the expression of SIRT1 mRNA and protein in patients with PDR (mRNA with vs. without resveratrol, 0.80±0.10 vs. 0.54±0.08; protein with vs. without resveratrol, 0.20±0.02 vs. 0.11±0.01; both P<0.05; Figs. 4 and 5). However, SIRT1 expression levels remained lower in the PBMCs of patients with PDR following stimulation with resveratrol (P<0.05), as compared with those from the control group. SIRT1 expression levels in the controls were not significant affected by resveratrol administration (P>0.05; Figs. 4 and 5). IL-17 expression levels in the PBMC supernatants from patients with PDR were inhibited by resveratrol (with vs. without resveratrol, 368.5±62.72 vs. 419.3±53.7 pg/ml), and they were not altered in the control subjects (with vs. without resveratrol, 207.6±39.5 vs. 182.5±50.3 pg/ml; supernatant with vs. without resveratrol, 0.20±0.02 vs. 0.11±0.01; both P>0.05; Fig. 3).

Discussion

The results of the present study indicated that serum IL-17 expression levels were increased in patients with PDR, as compared with non-diabetic control subjects with idiopathic macular epiretinal membranes. PBMCs exhibited increased expression levels of IL-17 in patients with PDR, whereas SIRT1 mRNA and protein expression levels were decreased in the PBMCs of patients with PDR. Furthermore, increased expression levels of SIRT1 were detected on the fibrovascular membranes of samples harvested from patients with PDR. These results suggested an imbalance in IL-17 and SIRT1, which may contribute to the pathogenesis of DR; therefore, SIRT1 may have protective effects in PDR.

IL-17, which is secreted by various cells including Th17 cells, is a key cytokine responsible for the recruitment, activation and migration of neutrophils. Furthermore, IL-17 is capable of inducing nonimmune cells, including endothelium and epithelium cells, to secrete proinflammatory factors (25). Previous studies have demonstrated that IL-17 has a pathological role in inflammatory and autoimmune diseases, as elevated levels of serum IL-17 have been detected in patients with diabetes (26), rheumatoid arthritis (27), psoriasis (28), multiple sclerosis (29) and systemic lupus erythematosus (30). Furthermore, IL-17 is capable of promoting angiogenesis by directly acting on endothelial cells and via other lymphokines with angiogenic properties (31). IL-17 is also capable of promoting the expression of VEGF, which is crucial in the development of PDR (32). In the present study, IL-17 expression levels were elevated in the sera and PBMCs of patients with PDR, which was consistent with previous results (11). The results of the present study also demonstrated that patients with PDR and T2D suffer from systemic inflammation, as IL-17 is capable of inducing the secretion of inflammatory factors in the endothelium, which subsequently disrupts tight junctions and the blood-retinal barrier (33); therefore, the increased expression levels of IL-17 in patients with PDR leads to retinal damage. Local expression levels of IL-17 in the vitreous fluid or retina should be investigated in future studies.

Previous studies have implicated SIRT1 in the regulation of inflammatory responses (34,35), in particular, it has been demonstrated that SIRT1 is capable of modulating IL-17 production (19,36); however, whether SIRT1 regulates IL-17 signaling in patients with DR remains unknown. In the present study, SIRT1 expression levels were reduced in the PBMCs of patients with PDR and, following treatment of the PBMCs with a SIRT1 activator, resveratrol, SIRT1 expression levels were upregulated. Consistent with previous studies (18,19), IL-17 expression levels were inhibited by SIRT1 activation in the present study; however, in contrast with the present hypothesis that SIRT1 expression levels may be downregulated in the fibrovascular membranes of patients with PDR, SIRT1 expression was upregulated, which is consistent with the findings of Maloney et al (37). This may be due to a protective feedback mechanism in the retina; however, the precise underlying mechanism remains unclear and requires further study. Therefore, the results of present study indicated that SIRT1 may have a protective effect against DR.

There were a number of limitations to the present study. Although IL-17 and SIRT1 expression levels were compared between patients with PDR and non-diabetic controls, the associations between the two factors and the duration of PDR were not evaluated due to limitations in the number of patients. Furthermore, SIRT1 activity may reflect the function of SIRT1, however, measuring SIRT1 activity using a fluorescent SIRT1 enzymatic assay may yield artifacts and is therefore not considered to be reliable by the majority of researchers (38). As an alternative, SIRT1 mRNA and protein expression levels were measured.

In conclusion, the present study demonstrated that IL-17 expression levels were increased in the serum of patients with PDR. In addition, IL-17 expression was upregulated and SIRT1 expression levels were decreased in the PBMCs of patients with PDR. Stimulation of SIRT1 may inhibit the production of IL-17 in patients with PDR. The molecular mechanisms underlying this are complex and an improved understanding of this interplay may elucidate a new therapeutic target for the treatment of PDR.

Acknowledgements

This study was supported by National Key Clinical Specialities Construction Program of China.

References

1 

Hendrick AM, Gibson MV and Kulshreshtha A: Diabetic retinopathy. Prim Care. 42:451–464. 2015. View Article : Google Scholar : PubMed/NCBI

2 

Zhang X, Bao S, Lai D, Rapkins RW and Gillies MC: Intravitreal triamcinolone acetonide inhibits breakdown of the blood-retinal barrier through differential regulation of VEGF-A and its receptors in early diabetic rat retinas. Diabetes. 57:1026–1033. 2008. View Article : Google Scholar : PubMed/NCBI

3 

Frank RN: Diabetic retinopathy. N Engl J Med. 350:48–58. 2004. View Article : Google Scholar : PubMed/NCBI

4 

Yau JW, Rogers SL, Kawasaki R, Lamoureux EL, Kowalski JW, Bek T, Chen SJ, Dekker JM, Fletcher A, Grauslund J, et al: Meta-Analysis for Eye Disease (META-EYE) Study Group: Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 35:556–564. 2012. View Article : Google Scholar : PubMed/NCBI

5 

Cheung CM, Vania M, Ang M, Chee SP and Li J: Comparison of aqueous humor cytokine and chemokine levels in diabetic patients with and without retinopathy. Mol Vis. 18:830–837. 2012.PubMed/NCBI

6 

Giacco F and Brownlee M: Oxidative stress and diabetic complications. Circ Res. 107:1058–1070. 2010. View Article : Google Scholar : PubMed/NCBI

7 

Milne R and Brownstein S: Advanced glycation end products and diabetic retinopathy. Amino Acids. 44:1397–1407. 2013. View Article : Google Scholar : PubMed/NCBI

8 

Xu H, Cai M and Zhang X: Effect of the blockade of the IL-23-Th17-IL-17A pathway on streptozotocin-induced diabetic retinopathy in rats. Graefes Arch Clin Exp Ophthalmol. 253:1485–1492. 2015. View Article : Google Scholar : PubMed/NCBI

9 

Afzal N, Zaman S, Asghar A, Javed K, Shahzad F, Zafar A and Nagi AH: Negative association of serum IL-6 and IL-17 with type-II diabetes retinopathy. Iran J Immunol. 11:40–48. 2014.PubMed/NCBI

10 

Takeuchi M, Sato T, Tanaka A, Muraoka T, Taguchi M, Sakurai Y, Karasawa Y and Ito M: Elevated levels of cytokins associated with Th2 and Th17 cells in vitreous fluid of proliferative diabetic retinopathy patients. PLoS One. 10:e01373582015. View Article : Google Scholar : PubMed/NCBI

11 

Nadeem A, Javaid K, Sami W, Zafar A, Jahan S, Zaman S and Nagi A: Inverse relationship of serum IL-17 with type-II diabetes retinopathy. Clin Lab. 59:1311–1317. 2013.PubMed/NCBI

12 

Afzal N, Zaman S, Shahzad F, Javaid K, Zafar A and Nagi AH: Immune mechanisms in type-2 diabetic retinopathy. J Pak Med Assoc. 65:159–163. 2015.PubMed/NCBI

13 

Longo VD and Kennedy BK: Sirtuins in aging and age-related disease. Cell. 126:257–268. 2006. View Article : Google Scholar : PubMed/NCBI

14 

Li T, Zhang J, Feng J, Li Q, Wu L, Ye Q, Sun J, Lin Y, Zhang M, Huang R, et al: Resveratrol reduces acute lung injury in a LPS-induced sepsis mouse model via activation of Sirt1. Mol Med Rep. 7:1889–1895. 2013.PubMed/NCBI

15 

Sung B, Chung JW, Bae HR, Choi JS, Kim CM and Kim ND: Humulus japonicus extract exhibits antioxidative and anti-aging effects via modulation of the AMPK-SIRT1 pathway. Exp Ther Med. 9:1819–1826. 2015.PubMed/NCBI

16 

Balaiya S, Khetpal V and Chalam KV: Hypoxia initiates sirtuin1-mediated vascular endothelial growth factor activation in choroidal endothelial cells through hypoxia inducible factor-2α. Mol Vis. 18:114–120. 2012.PubMed/NCBI

17 

Zheng Z, Chen H, Li J, Li T, Zheng B, Zheng Y, Jin H, He Y, Gu Q and Xu X: Sirtuin 1-mediated cellular metabolic memory of high glucose via the LKB1/AMPK/ROS pathway and therapeutic effects of metformin. Diabetes. 61:217–228. 2012. View Article : Google Scholar : PubMed/NCBI

18 

Gardner PJ, Joshi L, Lee RW, Dick AD, Adamson P and Calder VL: SIRT1 activation protects against autoimmune T cell-driven retinal disease in mice via inhibition of IL-2/Stat5 signaling. J Autoimmun. 42:117–129. 2013. View Article : Google Scholar : PubMed/NCBI

19 

Park YD, Kim YS, Jung YM, Lee SI, Lee YM, Bang JB and Kim EC: Porphyromonas gingivalis lipopolysaccharide regulates interleukin (IL)-17 and IL-23 expression via SIRT1 modulation in human periodontal ligament cells. Cytokine. 60:284–293. 2012. View Article : Google Scholar : PubMed/NCBI

20 

Alberti KG and Zimmet PZ: Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: Diagnosis and classification of diabetes mellitus provisional report of a WHO consultation. Diabetic Med. 15:539–553. 1998. View Article : Google Scholar : PubMed/NCBI

21 

Remmele W and Stegner HE: Recommendation for uniform definition of an immunoreactive score (IRS) for immunohistochemical estrogen receptor detection (ER-ICA) in breast cancer tissue. Der Pathologe. 8:138–140. 1987.(In German). PubMed/NCBI

22 

Wang C, Tian Y, Ye Z, Kijlstra A, Zhou Y and Yang P: Decreased interleukin 27 expression is associated with active uveitis in Behçet's disease. Arthritis Res Ther. 16:R1172014. View Article : Google Scholar : PubMed/NCBI

23 

Howitz KT, Bitterman KJ, Cohen HY, Lamming DW, Lavu S, Wood JG, Zipkin RE, Chung P, Kisielewski A, Zhang LL, et al: Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan. Nature. 425:191–196. 2003. View Article : Google Scholar : PubMed/NCBI

24 

Livak KJ and Schmittgen TD: Analysis of relative gene expression data using real-time quantitative PCR and the 2(−Delta Delta C(T)) Method. Methods. 25:402–408. 2001. View Article : Google Scholar : PubMed/NCBI

25 

Park H, Li Z, Yang XO, Chang SH, Nurieva R, Wang YH, Wang Y, Hood L, Zhu Z, Tian Q and Dong C: A distinct lineage of CD4 T cells regulates tissue inflammation by producing interleukin 17. Nat Immunol. 6:1133–1141. 2005. View Article : Google Scholar : PubMed/NCBI

26 

Sumarac-Dumanovic M, Jeremic D, Pantovic A, Janjetovic K, Stamenkovic-Pejkovic D, Cvijovic G, Stevanovic D, Micic D and Trajkovic V: Therapeutic improvement of glucoregulation in newly diagnosed type 2 diabetes patients is associated with a reduction of IL-17 levels. Immunobiology. 218:1113–1118. 2013. View Article : Google Scholar : PubMed/NCBI

27 

Zizzo G, De Santis M, Bosello SL, Fedele AL, Peluso G, Gremese E, Tolusso B and Ferraccioli G: Synovial fluid-derived T helper 17 cells correlate with inflammatory activity in arthritis, irrespectively of diagnosis. Clin Immunol. 138:107–116. 2011. View Article : Google Scholar : PubMed/NCBI

28 

Lynde CW, Poulin Y, Vender R, Bourcier M and Khalil S: Interleukin 17A: Toward a new understanding of psoriasis pathogenesis. J Am Acad Dermatol. 71:141–150. 2014. View Article : Google Scholar : PubMed/NCBI

29 

Esendagli G, Kurne AT, Sayat G, Kilic AK, Guc D and Karabudak R: Evaluation of Th17-related cytokines and receptors in multiple sclerosis patients under interferon β-1 therapy. J Neuroimmunol. 255:81–84. 2013. View Article : Google Scholar : PubMed/NCBI

30 

Wong CK, Lit LC, Tam LS, Li EK, Wong PT and Lam CW: Hyperproduction of IL-23 and IL-17 in patients with systemic lupus erythematosus: Implications for Th17-mediated inflammation in auto-immunity. Clin Immunol. 127:385–393. 2008. View Article : Google Scholar : PubMed/NCBI

31 

Numasaki M, Fukushi J, Ono M, Narula SK, Zavodny PJ, Kudo T, Robbins PD, Tahara H and Lotze MT: Interleukin-17 promotes angiogenesis and tumor growth. Blood. 101:2620–2627. 2003. View Article : Google Scholar : PubMed/NCBI

32 

Suryawanshi A, Veiga-Parga T, Reddy PB, Rajasagi NK and Rouse BT: IL-17A differentially regulates corneal vascular endothelial growth factor (VEGF)-A and soluble VEGF receptor 1 expression and promotes corneal angiogenesis after herpes simplex virus infection. J Immunol. 188:3434–3446. 2012. View Article : Google Scholar : PubMed/NCBI

33 

Chen Y, Yang P, Li F and Kijlstra A: The effects of Th17 cytokines on the inflammatory mediator production and barrier function of ARPE-19 cells. PLoS One. 6:e181392011. View Article : Google Scholar : PubMed/NCBI

34 

Lee SI, Min KS, Bae WJ, Lee YM, Lee SY, Lee ES and Kim EC: Role of SIRT1 in heat stress- and lipopolysaccharide-induced immune and defense gene expression in human dental pulp cells. J Endod. 37:1525–1530. 2011. View Article : Google Scholar : PubMed/NCBI

35 

Kim YS, Lee YM, Park JS, Lee SK and Kim EC: SIRT1 modulates high-mobility group box 1-induced osteoclastogenic cytokines in human periodontal ligament cells. J Cell Biochem. 111:1310–1320. 2010. View Article : Google Scholar : PubMed/NCBI

36 

Beier UH, Wang L, Bhatti TR, Liu Y, Han R, Ge G and Hancock WW: Sirtuin-1 targeting promotes Foxp3+ T-regulatory cell function and prolongs allograft survival. Mol Cell Biol. 31:1022–1029. 2011. View Article : Google Scholar : PubMed/NCBI

37 

Maloney SC, Antecka E, Granner T, Fernandes B, Lim LA, Orellana ME and Burnier MN Jr: Expression of SIRT1 in choroidal neovascular membranes. Retina. 33:862–866. 2013. View Article : Google Scholar : PubMed/NCBI

38 

Pacholec M, Bleasdale JE, Chrunyk B, Cunningham D, Flynn D, Garofalo RS, Griffith D, Griffor M, Loulakis P and Pabst B: SRT1720, SRT2183, SRT1460, and resveratrol are not direct activators of SIRT1. J Biol Chem. 285:8340–8351. 2010. View Article : Google Scholar : PubMed/NCBI

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Liu S, Lin Y and Liu X: Protective effects of SIRT1 in patients with proliferative diabetic retinopathy via the inhibition of IL-17 expression. Exp Ther Med 11: 257-262, 2016.
APA
Liu, S., Lin, Y., & Liu, X. (2016). Protective effects of SIRT1 in patients with proliferative diabetic retinopathy via the inhibition of IL-17 expression. Experimental and Therapeutic Medicine, 11, 257-262. https://doi.org/10.3892/etm.2015.2877
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Liu, S., Lin, Y., Liu, X."Protective effects of SIRT1 in patients with proliferative diabetic retinopathy via the inhibition of IL-17 expression". Experimental and Therapeutic Medicine 11.1 (2016): 257-262.
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Liu, S., Lin, Y., Liu, X."Protective effects of SIRT1 in patients with proliferative diabetic retinopathy via the inhibition of IL-17 expression". Experimental and Therapeutic Medicine 11, no. 1 (2016): 257-262. https://doi.org/10.3892/etm.2015.2877