Diabetic nephropathy: the role of inflammation in fibroblast activation and kidney fibrosis

Burdock Fructooligosaccharide Protects Against Diabetic Nephropathy in Mice by Regulating Nrf2 Signaling

Diabetic nephropathy (DN) is a common complication of diabetes mellitus, with oxidative stress playing a critical role in its development. Burdock fructooligosaccharide (BFO), a major compound in Burdock, exhibits antioxidative effects. However, its mechanisms of action and effects on diabetic nephropathy are not clear enough. This study aims to explore the mechanisms of BFO and its impact on streptozotocin-induced diabetic nephropathy in mice. Male C57BL/6J mice were randomly divided into normal control, DN, and BFO groups. Relevant serum biochemical parameters were detected using kits. Renal injury was evaluated through fluorescence microscopy, histopathology, and transmission electron microscopy. Nrf2/HO-1 signaling was analyzed via quantitative real-time PCR, western blotting, and immunohistochemistry. In DN mice, BFO significantly reduced fasting blood glucose, kidney index, urine protein, serum creatinine, blood urea nitrogen, total cholesterol, triglyceride, and low-density lipoprotein cholesterol, while significantly increasing high-density lipoprotein, SOD, and CAT levels. Additionally, BFO protected against streptozotocin-induced renal injury, restored podocyte function, increased both mRNA and protein expression of Nrf2, HO-1, and Bcl-2, and decreased those of Bax. In conclusion, BFO can be used to treat streptozotocin-induced renal injury in mice and is a promising candidate for diabetic nephropathy treatment.

Research progress on small extracellular vesicles in diabetic nephropathy

Virtually all cell types are capable of secreting small extracellular vesicles (sEV), which can be internalized by recipient cells, thereby serving as vehicles for intercellular communication. The cargoes of these vesicles, such as microRNAs, circular RNAs, proteins, and lipids, play significant roles in both normal cellular functions and the pathogenesis of various diseases. Diabetic Nephropathy (DN), a complication arising from diabetes, is expected to contribute to a 54% increase in the global diabetic population between 2015 and 2030, leading to substantial economic burdens on individuals and healthcare systems. sEVs, as promising biomarkers, demonstrate diverse mechanistic responses in different types of Diabetic Kidney Disease (DKD). They also hold advantages in the early prediction of renal damage. This article reviews the functional mechanisms of sEVs in DKD and their potential as therapeutic targets and biomarkers.

Induced Genetic Deletion of Cell Division Autoantigen 1 in Adulthood Attenuates Diabetes-Associated Renal Fibrosis

Cell Division Autoantigen 1 (CDA1) has been shown to play a role in enhancing transforming growth factor beta (TGFβ) signaling, leading to fibrosis in diabetic kidney disease (DKD) using mouse strains with global CDA1 gene deletion. In these models, diabetes has been induced, leading to DKD in the absence of CDA1. It is still unknown whether inhibition of CDA1 activity after onset of diabetes in the presence of CDA1 can attenuate renal fibrosis in vivo. Thus, we examined the effect of inducing genetic deletion of CDA1 in adulthood in mice using a tamoxifen-activated estrogen receptor fused cyclization recombinase (ERCre)-Locus of cross-over in P1 (LoxP) system. Male mice at 6-8 weeks of age were rendered diabetic with streptozotocin (STZ) or injected with buffer alone to serve as non-diabetic controls. Five weeks later, genetic deletion of CDA1 was induced by tamoxifen administration in CDA1Flox/ERCre mice, with mice injected with vehicle to serve as CDA1 wildtype controls. Kidney tissues were analyzed 5 weeks after deletion of CDA1. Tamoxifen administration reduced CDA1 gene expression by ~80% in CDA1Flox/ERCre mice. Renal levels of phosphorylated Smad3 and expression of profibrotic genes as well as accumulation of extracellular matrix proteins (ECMs) such as collagens III and IV were increased in diabetic mice, and induced deletion of CDA1 led to attenuation of these parameters. Therefore, targeting CDA1 after onset of diabetes in mice where CDA1 was initially expressed is able to attenuate diabetes-associated renal injury, providing the impetus to target this pathway in order to reduce diabetic kidney disease.

Gut-kidney interaction reinforces dapagliflozin-mediated alleviation in diabetic nephropathy

Intestinal microbiota are pathophysiologically involved in diabetic nephropathy (DN). Dapagliflozin, recognized for its blood glucose-lowering effect, has demonstrated efficacy in improving DN. However, the mechanisms beyond glycemic control that mediate the impact of dapagliflozin on DN remain unclear. Here, we investigated the effects of dapagliflozin on DN and gut microbiota, elucidating how it mitigates DN via the gut-kidney axis. Low-dose dapagliflozin markedly ameliorated renal inflammation and fibrosis and improved gut barrier function in high-fat diet (HFD)/streptozotocin (STZ)-induced DN mice and db/db mice without affecting blood glucose levels. These effects were associated with altered gut microbial composition and function. Eradication of the resident microbiota abolished the protective effects of dapagliflozin against kidney injury in DN mice. Moreover, dapagliflozin significantly altered microbial metabolites in DN mice, decreasing argininosuccinic acid (ASA) and palmitic acid (PA), while increasing S-allylcysteine (SAC) levels. ASA and PA increased the expression of renal inflammation- and fibrosis-related markers in HK-2 cells, whereas SAC ameliorated renal damage and altered the microbial composition in a manner similar to dapagliflozin in DN mice. Notably, Muribaculaceae and Desulfovibrionaceae were correlated with the alleviation of DN-associated renal dysfunction by low- and high-dose dapagliflozin treatments in DN mice. These findings demonstrate a potential application of dapagliflozin in managing DN by targeting the gut microbiota.NEW & NOTEWORTHY We demonstrated that dapagliflozin administration alleviated renal inflammation and fibrosis in vivo and in vitro, along with reshaping the gut microbiota composition and altering levels of key microbial metabolites, including argininosuccinic acid (ASA) and palmitic acid (PA), while increasing S-allylcysteine (SAC). Importantly, the genera Muribaculaceae and Desulfovibrionaceae emerged as pivotal microbial genera mediating the protective effects of dapagliflozin against diabetic nephropathy.

Gambogic Acid Mitigates Nephropathy by Inhibiting Oxidative Stress and Inflammation in Diabetic Rats

Diabetic nephropathy is a leading cause of end-stage renal disease globally, with limited treatment options to prevent its progression. Gambogic acid (GA), a xanthone isolated from Garcinia hanburyi, has shown notable anti-oxidative, anti-inflammatory, and anti-proliferative properties. This study aimed to assess GA's renoprotective effects in a model of diabetic nephropathy mediated by low dose streptozotocin (STZ) combined with a high-fat diet, focusing on its potential to reduce oxidative stress and inflammation. Control-treated vehicle and STZ/high-fat diet-mediated diabetic rats were administered either the vehicle or 3 or 6 mg/kg of GA to assess its effects on renal inflammation, fibrosis, and oxidative stress. Renal histological changes were assessed, and markers for inflammation and oxidative stress, including I-κBα, p-p38/MAPK, and p-p65NF-κB pathways, were measured to explore the mechanisms of GA. Diabetic rats showed significant renal dysfunction, structural damage, and increased inflammation and fibrosis. Treatment with GA markedly improved renal structure and function. GA also reduced oxidative stress, increased I-κBα expression, and inhibited key signaling pathways, specifically p-p38/MAPK and p-p65NF-κB, involved in cellular inflammation. GA exhibits promising renoprotective effects in diabetic nephropathy by reducing oxidative stress and inflammation, supporting its potential as a natural therapeutic agent for diabetic renal disease.

Cyproheptadine, a SET7/9 inhibitor, reduces hyperglycaemia-induced ER stress alleviating inflammation and fibrosis in renal tubular epithelial cells

CONTEXT

Persistent hyperglycaemia increases SET7/9 expression and endoplasmic reticulum (ER) stress which causes inflammation, apoptosis, and fibrosis in renal tubular epithelial cells leading to diabetic kidney disease (DKD).

OBJECTIVE

Current study explores the renoprotective potential of a novel SET7/9 inhibitor, Cyproheptadine, and the underlying molecular mechanisms in hyperglycaemia-induced renal tubular epithelial cell injury.

METHODS

Change in expression of SET7/9, histone H3 lysine (K4) monomethylation (H3K4Me1), inflammatory, fibrotic, and ER stress proteins were evaluated in-vivo and in-vitro. NRK-52E cells were used to study the preventive effect of Cyproheptadine against hyperglycaemia-induced ER stress and subsequent inflammation and fibrosis.

RESULTS

SET7/9 and H3K4Me1 expression significantly increased with ER stress, inflammation, apoptosis, and fibrosis, in-vivo and in-vitro under hyperglycaemia. However, the cells treated with Cyproheptadine showed significant suppression of H3K4Me1 and reduction in ER stress, inflammation, apoptosis, and fibrosis.

CONCLUSION

Cyproheptadine prevented hyperglycaemia-induced renal fibrosis and inflammation by reducing H3K4Me1 expression and ER stress.

Long Non-coding RNA ZFAS1 Regulates Fibrosis and Scortosis in the Cell Model of Diabetic Nephropathy Through miR-525-5p/SGK1 Axis

Diabetic nephropathy (DN) is a common clinical syndrome in diabetic patients. Functional characterization of non-coding (ncRNAs) involved in the progression of DN can provide insights into the diagnosis and therapeutic management of DN. Human kidney proximal tubular epithelial cells (HK-2) were challenged by high glucose (HG, 50 mM) as a cell model of DN. The expression level of long non-coding RNA (lncRNA) ZFAS1 was quantified by qRT-PCR. The proteins and cytokines related to fibrosis and scortosis in DN (NLRP3, GSDMD-N, IL-1β and Caspase 1, fibronectin, collagen I, collagen III, IL-1β, and IL-18) were examined by western blot or ELISA. RNA precipitation and luciferase reporter activity experiments were conducted to assess the molecular associations. ZFAS1 and SGK1 were highly induced in HK-2 cells challenged with HG, while miR-525-5p downregulated upon HG treatment. ZFAS1 knockdown attenuated HG-induced fibrosis and scortosis in HK-2 cells by reducing the levels of NLRP3, GSDMD-N, Caspase 1, fibronectin, collagen I/III, IL-1β, and IL-18. Mechanically, ZFAS1 knockdown protected HK-2 cells from HG-induced injury by upregulating miR-525-5p and repressing SGK1 expression. Overall, our results suggest that knocking down ZFAS1 may be formulated as a protective strategy in ameliorating DN progression through regulating miR-525-5p/SGK1 pathway. Targeting ZFAS1 could be further explored as a potential approach for the management of DN.

Contrast-induced acute kidney injury: a review of definition, pathogenesis, risk factors, prevention and treatment

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired AKI, which seriously threatens the health of patients. To date, the precise pathogenesis of CI-AKI has remained not clear and may be related to the direct cytotoxicity, hypoxia and ischemia of medulla, and oxidative stress caused by iodine contrast medium, which have diverse physicochemical properties, including cytotoxicity, permeability and viscosity. The latest research shows that microRNAs (miRNAs) are also involved in apoptosis, pyroptosis, and autophagy which caused by iodine contrast medium (ICM), which may be implicated in the pathogenesis of CI-AKI. Unfortunately, effective therapy of CI-AKI is very limited at present. Therefore, effective prevention of CI-AKI is of great significance, and several preventive options, including hydration, antagonistic vasoconstriction, and antioxidant drugs, have been developed. Here, we review current knowledge about the features of iodine contrast medium, the definition, pathogenesis, molecular mechanism, risk factors, prevention and treatment of CI-AKI.

ELABELA-derived peptide ELA13 attenuates kidney fibrosis by inhibiting the Smad and ERK signaling pathways

Kidney fibrosis is an inevitable result of various chronic kidney diseases (CKDs) and significantly contributes to end-stage renal failure. Currently, there is no specific treatment available for renal fibrosis. ELA13 (amino acid sequence: RRCMPLHSRVPFP) is a conserved region of ELABELA in all vertebrates; however, its biological activity has been very little studied. In the present study, we evaluated the therapeutic effect of ELA13 on transforming growth factor-β1 (TGF-β1)-treated NRK-52E cells and unilateral ureteral occlusion (UUO) mice. Our results demonstrated that ELA13 could improve renal function by reducing creatinine and urea nitrogen content in serum, and reduce the expression of fibrosis biomarkers confirmed by Masson staining, immunohistochemistry, real-time polymerase chain reaction (RT-PCR), and western blot. Inflammation biomarkers were increased after UUO and decreased by administration of ELA13. Furthermore, we found that the levels of essential molecules in the mothers against decapentaplegic (Smad) and extracellular signal-regulated kinase (ERK) pathways were reduced by ELA13 treatment in vivo and in vitro. In conclusion, ELA13 protected against kidney fibrosis through inhibiting the Smad and ERK signaling pathways and could thus be a promising candidate for anti-renal fibrosis treatment.

Multi-organ single-cell RNA sequencing in mice reveals early hyperglycemia responses that converge on fibroblast dysregulation

Diabetes causes a range of complications that can affect multiple organs. Hyperglycemia is an important driver of diabetes-associated complications, mediated by biological processes such as dysfunction of endothelial cells, fibrosis, and alterations in leukocyte number and function. Here, we dissected the transcriptional response of key cell types to hyperglycemia across multiple tissues using single-cell RNA sequencing (scRNA-seq) and identified conserved, as well as organ-specific, changes associated with diabetes complications. By studying an early time point of diabetes, we focus on biological processes involved in the initiation of the disease, before the later organ-specific manifestations had supervened. We used a mouse model of type 1 diabetes and performed scRNA-seq on cells isolated from the heart, kidney, liver, and spleen of streptozotocin-treated and control male mice after 8 weeks and assessed differences in cell abundance, gene expression, pathway activation, and cell signaling across organs and within organs. In response to hyperglycemia, endothelial cells, macrophages, and monocytes displayed organ-specific transcriptional responses, whereas fibroblasts showed similar responses across organs, exhibiting altered metabolic gene expression and increased myeloid-like fibroblasts. Furthermore, we found evidence of endothelial dysfunction in the kidney, and of endothelial-to-mesenchymal transition in streptozotocin-treated mouse organs. In summary, our study represents the first single-cell and multi-organ analysis of early dysfunction in type 1 diabetes-associated hyperglycemia, and our large-scale dataset (comprising 67 611 cells) will serve as a starting point, reference atlas, and resource for further investigating the events leading to early diabetic disease.

Efficacy and safety of Abelmoschus manihot capsule combined with ACEI/ARB on diabetic kidney disease: a systematic review and meta analysis

Background: Diabetic kidney disease (DKD) is one of the most serious microvascular complications of diabetes, with the incidence rate increasing yearly, which is the leading cause of chronic kidney disease (CKD) and end-stage kidney disease. Abelmoschus Manihot capsule, as a proprietary Chinese patent medicine, is widely used for treating CKD in China. Currently, the combination of Abelmoschus Manihot (AM) capsule and renin-angiotensin-aldosterone system inhibitor (RASI) has gained popularity as a treatment option for DKD, with more and more randomized control trials (RCTs) in progress. However, the high-quality clinical evidence supporting its application in DKD is still insufficient. Aim of the study: To comprehensively and systematically evaluate the efficacy and safety of AM capsule combined with RASI in the treatment of DKD. Materials and methods: English and Chinese databases such as Pubmed, Cochrane Library, Embase, CNKI, SinoMed, WF, and VIP were searched to collect the RCTs of AM capsule in treatment of DKD. Then Two investigators independently reviewed and extracted data from the RCTs which met the inclusion criteria. The quality of the data was assessed using the Cochrane risk of bias assessment tool, and meta-analysis was performed using RevMan 5.4 software. Results: 32 RCTs with a total of 2,881 DKD patients (1,442 in the treatment group and 1,439 in the control group) were included. The study results showed that AM capsule combined with RASI could be more effective in decreasing 24h-UTP [MD = -442.05, 95% CI (-609.72, -274.38), p < 0.00001], UAER [MD = -30.53, 95% CI (-39.10, -21.96), p < 0.00001], UACR [MD = -157.93, 95% CI (-288.60, -27.25), p < 0.00001], Scr [MD = -6.80, 95% CI (-9.85, -3.74), p < 0.0001], and BUN [MD = -0.59, 95% CI (-1.07, -0.12), p = 0.01], compared to using RASI alone. According to the subgroup analyses, the combination of AM and ARB seems to be more effective in reducing UAER than the combination of ACEI, and the addition of AM may achieve a more significant clinical effect on decreasing Scr for DKD patients with 24h-UTP>2 g or Scr>110-133 μmol/L and >133 μmol/L. Furthermore, no additional adverse reactions were observed in the combination group [OR = 1.06; 95%CI: (0.66, 1.69), p = 0.82]. Conclusion: Combining AM with RASI may be a superior strategy for DKD treatment compared to RASI monotherapy. However, due to significant heterogeneity, the results should be interpreted with great caution, and more high-quality RCTs with multi-centers, different stages of DKD, large sample sizes, and long follow-up periods are still needed to improve the evidence quality of AM for DKD in the future. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#recordDetails; Identifier CRD42022351422.

(5R)-5-hydroxytriptolide ameliorates diabetic kidney damage by inhibiting macrophage infiltration and its cross-talk with renal resident cells

OBJECTIVE

Diabetic nephropathy (DN) is the main cause of end-stage renal disease, and there are no targeted treatment options at present. The efficacy of the new immunosuppressive drug (5R)-5-hydroxytriptolide (LLDT8) in improving kidney inflammation has been demonstrated in multiple studies. The present study was intended to investigate the preventive and therapeutic effects of LLDT8 on DN and to reveal its potential pharmacological mechanisms.

METHODS

The effects of LLDT8 on liver and kidney functions, and urine microprotein of Streptozotocin (STZ) induced DN mice were detected. The protective effect of LLDT8 on the kidney tissue was observed by pathological staining and transmission electron microscopy. Cell culture experiments were performed to detect the effects of LLDT8 on the expression of chemokines and epithelial-mesenchymal transition (EMT) in high glucose-induced TCMK1 cells using real-time polymerase chain reaction (RT-PCR) and western blot (WB) techniques and to detect the influence of LLDT8 on the secretion of pro-inflammatory and pro-fibrotic factors in high glucose-induced RAW264.7 cells.

RESULTS

In animal experiments, treatment with high-dose LLDT8 (0.25 mg/kg/2d) reduced 24 h urinary albumin excretion, improved structural kidney damage, and delayed fibrosis progression in DN mice. Immunofluorescence results showed that LLDT8 intervention reduced macrophage infiltration in kidney tissues of DN mice. PCR and WB results of kidney tissues showed reduced expressions of chemokines CCL2 and M-CSF1 in the LLDT8 intervention group compared to the DN group. In cellular assays, LLDT8 treatment reduced chemokine secretion in high glucose-induced TCMK1 cells, but had no effect on EMT of TCMK1 cells. LLDT8 treatment reduced the secretion of pro-inflammatory and pro-fibrotic factors in high glucose-induced RAW264.7 cells.

CONCLUSIONS

The present study suggests that LLDT8 could effectively inhibit the secretion of pro-inflammatory and pro-fibrotic factors by macrophages, which could alleviate high glucose-induced renal tissue injury and slow down the process of tissue fibrosis and DN.

Treatment for type 2 diabetes and diabetic nephropathy by targeting Smad3 signaling

TGF-β/Smad3 signaling plays a critical role in type 2 diabetes (T2D) and type 2 diabetic nephropathy (T2DN), but treatment by specifically targeting Smad3 remains unexplored. To develop a new Smad3-targeted therapy for T2D and T2DN, we treated db/db mice at the pre-diabetic or established diabetic stage with a pharmacological Smad3 inhibitor SIS3. The therapeutic effect and mechanisms of anti-Smad3 treatment on T2D and T2DN were investigated. We found that anti-Smad3 treatment on pre-diabetic db/db mice largely attenuated both T2D and T2DN by markedly reducing blood glucose levels, and inhibiting the elevated serum creatinine, microalbuminuria, and renal fibrosis and inflammation. Unexpectedly, although SIS3 treatment on the established diabetic db/db mice inhibited T2DN but did not significantly improve T2D. Mechanistically, we uncovered that inhibition of T2DN in SIS3-treated db/db mice was associated with effectively restoring the balance of TGF-β/Smad signaling by inhibiting Smad3 while increasing Smad7, thereby suppressing Smad3-mediated renal fibrosis and NF-κB-driven renal inflammation via lncRNA Erbb4-IR and LRN9884-dependent mechanisms. We also revealed that inhibition of islet β cell injury by preventing the loss of islet Pax 6 could be the mechanism through which the pre-diabetic treatment, rather than the late SIS3 treatment on db/db mice significantly improved the T2D phenotype.

Targeting Src homology phosphatase 2 ameliorates mouse diabetic nephropathy by attenuating ERK/NF-κB pathway-mediated renal inflammation

Renal inflammation is a pivotal mechanism underlying the pathophysiology of diabetic nephropathy (DN). The Src homology phosphatase 2 (SHP2) has been demonstrated to be linked to diabetes-induced inflammation, yet its roles and explicit molecular mechanisms in DN remain unexplored. Here, we report that SHP2 activity is upregulated in both DN patients and db/db mice. In addition, pharmacological inhibition of SHP2 with its specific inhibitor PHPS1 alleviates DN in db/db mice and attenuates renal inflammation. In vitro, PHPS1 administration prevents inflammatory responses in HK-2 cells stimulated by high glucose (HG). Mechanistically, PHPS1 represses HG-induced activation of the proinflammatory ERK/NF-κB signaling pathway, and these inhibitory effects are blocked in the presence of an ERK specific inhibitor, hence demonstrating that PHPS1 suppresses ERK/NF-κB pathway-mediated inflammation. Moreover, PHPS1 retards ERK/NF-κB pathway activation in db/db mice, and histologically, SHP2 activity is positively correlated with ERK/NF-κB activation in DN patients. Taken together, these findings identify SHP2 as a potential therapeutic target and show that its pharmacological inhibition might be a promising strategy to mitigate DN. Video Abstract.

Promising therapeutic mechanism for Chinese herbal medicine in ameliorating renal fibrosis in diabetic nephropathy

Diabetic nephropathy (DN) is one of the most serious chronic microvascular abnormalities of diabetes mellitus and the major cause of uremia. Accumulating evidence has confirmed that fibrosis is a significant pathological feature that contributes to the development of chronic kidney disease in DN. However, the exact mechanism of renal fibrosis in DN is still unclear, which greatly hinders the treatment of DN. Chinese herbal medicine (CHM) has shown efficacy and safety in ameliorating inflammation and albuminuria in diabetic patients. In this review, we outline the underlying mechanisms of renal fibrosis in DN, including oxidative stress (OS) generation and OS-elicited ASK1-p38/JNK activation. Also, we briefly summarize the current status of CHM treating DN by improving renal fibrosis. The treatment of DN by inhibiting ASK1 activation to alleviate renal fibrosis in DN with CHM will promote the discovery of novel therapeutic targets for DN and provide a beneficial therapeutic method for DN.

Highly water-soluble diacetyl chrysin ameliorates diabetes-associated renal fibrosis and retinal microvascular abnormality in db/db mice

BACKGROUND/OBJECTIVES

Chronic or intermittent hyperglycemia is associated with the development of diabetic complications. Oxidative stress and inflammation can be altered by hyperglycemia in diverse tissues, including kidneys and eyes, and play a pivotal role in diabetic complications. Our previous studies showed that the water-insoluble 5,7-dihydroxyflvone chrysin effectively combats diabetic damages incurred in diabetic kidneys and retinas. The current study employed the newly-synthesized 5.7-di-O-acetylchrysin, having higher solubility than chrysin, to compare the effects on diabetes-associated renal fibrosis and abnormal retinal neovascularization.

MATERIALS/METHODS

In the in vivo study, db/db mice as animal models of type 2 diabetes were orally administrated 10 mg/kg BW diacetylchrysin, daily for 10 weeks.

RESULTS

Unlike chrysin, oral administration of 10 mg/kg diacetylchrysin did not lower the blood glucose level and 24 h urine volume in db/db mice. Nevertheless, the urinary albumin excretion was markedly reduced. The administration of diacetylchrysin also diminished the deposition of collagen fibers in diabetic glomeruli and tubules by suppressing the induction of connective tissue growth factor and collagen IV in diabetic kidneys. Supplying diacetylchrysin enhanced the membrane type-1 matrix metalloproteinase (MMP) expression reduced in diabetic kidneys, while the tissue inhibitor of MMP-2 induction was attenuated in diacetylchrysin-challenged diabetic kidneys. In addition, supplementing diacetylchrysin to diabetic mice ameliorated renal injury due to glomerulosclerosis and tubular interstitial fibrosis. Furthermore, the reduced retinal inductions of Zonula occludens-1 and vascular endothelial cadherin in db/db mice were elevated in the retinal tissues of diacetylchrysin-treated animals. Oral administration of diacetylchrysin curtailed the induction of vascular endothelial growth factor (VEGF) and VEGF receptor 2 in db/db mice, ultimately retarding diabetes-associated retinal neovascularization. Additionally, the retinal formation of acellular capillaries with leaky vessels was reduced in diacetylchrysin-treated db/db mice.

CONCLUSION

Diacetylchrysin may act as a potent pro-health agent for treating renal fibrosis-associated diabetic nephropathy and retinal neovascularization-associated diabetic retinopathy.

Metformin suppresses LRG1 and TGFβ1/ALK1-induced angiogenesis and protects against ultrastructural changes in rat diabetic nephropathy

Diabetic nephropathy (DN) has high prevalence and poor prognosis which make it a research priority for scientists. Since metformin, a hypoglycaemic drug, has been found to prolong the survival of mice with DN. This study aims at investigating the molecular mechanisms leading to DN in rats and to explore the role of leucine-rich α-2-glycoprotein-1 (LRG1), activin-like kinase1 (ALK1), and transforming growth factor-β (TGFβ1) in the pathologic alterations seen in DN. The aim was also extended to explore the protective action of metformin against DN in rats and its influence on LRG1and ALK1/TGFβ1 induced renal angiogenesis. 24 male rats were used. Rats were assigned as, the vehicle group, the diabetic control group and diabetic + metformin (100 and 200 mg/kg) groups. Kidney samples were processed for histopathology, immunohistochemistry and biochemical analysis. Bioinformatic analysis of studied proteins was done to determine protein-protein interactions. Metformin reduced serum urea and creatinine significantly, decreased the inflammatory cytokine levels and reduced LRG1, TGFβ1, ALK1 and vascular endothelial growth factor (VEGF) proteins in rat kidneys. Bioinformatic analysis revealed interactions between the studied proteins. Metformin alleviated the histopathological changes observed in the diabetic rats such as the glomerular surface area and increased Bowman's space diameter. Metformin groups showed decreased VEGF immunostaining compared to diabetic group. Metformin shows promising renoprotective effects in diabetic model that was at least partly mediated by downregulation of LRG1 and TGFβ1/ALK1-induced renal angiogenesis. These results further explain the molecular mechanism of metformin in DN management.

Cell-Cycle Dysregulation in the Pathogenesis of Diabetic Kidney Disease: An Update

In the last few decades, the prevalence of diabetes mellitus (DM) has increased rapidly. Diabetic kidney disease (DKD) is the major cause of end-stage renal disease (ESRD) globally, attributed to hemodynamic changes and chronic hyperglycemia. Recent findings have emphasized the role of cell-cycle dysregulation in renal fibrosis and ESRD. Under normal physiological conditions, most mature renal cells are arrested in the G0 phase of the cell cycle, with a rather low rate of renewal. However, renal cells can bypass restriction points and re-enter the cell cycle under stimulation of injuries induced via metabolic disorders. Mild injuries activate proliferation of renal cells to compensate for cell loss and reinstate renal function, while severe or repeated injuries will lead to DNA damage and maladaptive repair which ultimately results in cell-cycle arrest or overproliferation, and eventually promote renal fibrosis and ESRD. In this review, we focus on the role of cell-cycle dysregulation in DKD and discuss new, emerging pathways that are implicated in the process.

NUP160 knockdown inhibits the progression of diabetic nephropathy in vitro and in vivo

Diabetic nephropathy (DN) is a severe diabetic complication and podocyte damage is a hallmark of DN. The Nucleoporin 160 (NUP160) gene was demonstrated to regulate cell proliferation and apoptosis in mouse podocytes. This study explored the possible role and mechanisms of NUP160 in high glucose-triggered podocyte injury. A rat model of DN was established by intraperitoneal injection of 60 mg/kg streptozotocin (STZ). Podocytes were treated with 33 mM high glucose. The effects of the Nup160 on DN and its mechanisms were assessed using MTT, flow cytometry, Western blot, ELISA, RT-qPCR, and luciferase reporter assays. The in vivo effects of NUP160 were analyzed by HE, PAS, and MASSON staining assays. The NUP160 level was significantly upregulated in podocytes treated with 33 mM high glucose. Functionally, NUP160 knockdown alleviated high glucose-induced apoptosis and inflammation in podocytes. Mechanistically, miR-495-3p directly targeted NUP160, and lncRNA HCG18 upregulated NUP160 by sponging miR-495-3p by acting as a ceRNA. Additionally, NUP160 overexpression reversed the effects of HCG18 knockdown in high glucose treated-podocytes. The in vivo assays indicated that NUP160 knockdown alleviated the symptoms of DN rats. NUP160 knockdown plays a key role in preventing the progression of DN, suggesting that targeting NUP160 may be a potential therapeutic strategy for DN treatment.

Changes in Metabolic Parameters in Patients with Diabetic Kidney Disease Depending on the Status of D3

BACKGROUND

Type 2 diabetes is a metabolic disease characterized by hyperglycemia as a result of insulin resistance and decreased insulin secretion. A relatively large number of patients with this type of diabetes have abdominal obesity, which also affects insulin resistance development. Chronic hyperglycemia can lead to damage and dysfunction of various organs, and a striking example is diabetic nephropathy. Diabetic nephropathy is a specific kind of kidney damage that occurs due to complications of diabetes and is accompanied by the formation of diffuse or nodular glomerulosclerosis, which can lead to terminal renal failure and requires immediate substitution through renal therapy or renal transplantation. Diabetic nephropathy is diagnosed with albuminuria and a decrease in the rate of glomerular filtration.

METHODS

This review was based on a literature search for the most important evidence of vitamin D as a possible method of prevention for obesity, type 2 diabetes, and diabetic nephropathy. Collected published articles were summarized according to their overall themes.

RESULTS

In this review, we considered vitamin D as a possible method of treatment for type 2 diabetes, as well as its complications, including diabetic nephropathy.

CONCLUSION

Studies show that vitamin D inhibits the renin-angiotensin-aldosterone system, resulting in improved renal function in diabetic nephropathy. Vitamin D also has antiinflammatory, antiproliferative, and anti-metastatic effects, which improve endothelial function.

Plasmacytoma Variant Translocation 1 (PVT1) Gene as a Potential Novel Target for the Treatment of Diabetic Nephropathy

Introduction: Diabetic nephropathy (DN), a severe microvascular complication in patients with diabetes, is clinically characterized by progressive decline in glomerular filtration rate (GFR). DN is the most common cause of end-stage renal disease (ESRD), and has a consistently high mortality rate. Despite the fact that the prevalence of DN is increasing worldwide, the molecular mechanism underlying the pathogenesis of DN is not fully understood. Previous studies indicated PVT1 as a key determinant of ESRD as well as a mediator of extracellular matrix (ECM) accumulation in vitro. More investigations into the role of PVT1 in DN development are needed. Objectives: To study the effect of PVT1 silencing on progression of DN in diabetic male C57BL/6 mice at early, intermediate and relatively advanced ages. Methods: Diabetic mice were treated with either scramble-siRNA (DM + siRNA (scramble)) or PVT1-siRNA (DM + siRNA (PVT1)), whereas the control mice were normal mice without siRNA injection (Control). Blood, urine and kidney were collected at the age of 9 (young), 16 (middle-aged) or 24 (old) weeks old. Kidney function, histology and molecular gene expression were evaluated. Results: Our findings showed that silencing of PVT1 reduced kidney hypertrophy, proteinuria (UAE, UACR, UPE, UPCR), serum creatinine, serum TGF-β1, serum insulin decline, glomerular and mesangial areas, and increased creatinine clearance in diabetic mice to levels closer to the age-matched controls. Also, silencing of PVT1 markedly suppressed the upregulation of PAI-1, TGF-β1, FN1, COL4A1, and downregulation of BMP7. Conclusion: Silencing of PVT1 ameliorates DN in terms of kidney function and histology in diabetic mice. The renoprotection is attributed to the reduction in ECM accumulation, TGF-β1 elevation and insulin decline. PVT1 is suggested to play an important role in ECM accumulation which makes it a possible target for the treatment of DN.

Renal fibrosis as a hallmark of diabetic kidney disease: Potential role of targeting transforming growth factor-beta (TGF-β) and related molecules

INTRODUCTION

Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease (ESRD) worldwide. Currently, there is no effective treatment to completely prevent DKD progression to ESRD. Renal fibrosis and inflammation are the major pathological features of DKD, being pursued as potential therapeutic targets for DKD.

AREAS COVERED

Inflammation and renal fibrosis are involved in the pathogenesis of DKD. Anti-inflammatory drugs have been developed to combat DKD but without efficacy demonstrated. Thus, we have focused on the mechanisms of TGF-β-induced renal fibrosis in DKD, as well as discussing the important molecules influencing the TGF-β signaling pathway and their potential development into new pharmacotherapies, rather than targeting the ligand TGF-β and/or its receptors, such options include Smads, microRNAs, histone deacetylases, connective tissue growth factor, bone morphogenetic protein 7, hepatocyte growth factor, and cell division autoantigen 1.

EXPERT OPINION

TGF-β is a critical driver of renal fibrosis in DKD. Molecules that modulate TGF-β signaling rather than TGF-β itself are potentially superior targets to safely combat DKD. A comprehensive elucidation of the pathogenesis of DKD is important, which requires a better model system and access to clinical samples via collaboration between basic and clinical researchers.

FGF1ΔHBS delays the progression of diabetic nephropathy in late-stage type 2 diabetes mouse model by alleviating renal inflammation, fibrosis, and apoptosis

Elderly adults are at higher risk for developing diabetic complications including diabetic nephropathy (DN), contributing to excess morbidity and mortality in elderly individuals. A non-mitogenic variant of fibroblast growth factor 1 (FGF1ΔHBS) was demonstrated to prevent DN in an early-stage (2-month-old) type 2 diabetes (T2D) mouse model. The present study aimed to investigate the potential therapeutic effects of FGF1ΔHBS against the progression of renal dysfunction in a late-stage T2D mouse model with established DN. Nine-month-old db/db mice were administered FGF1ΔHBS every other day for 3 months. db/db mice at 12-month-old without FGF1ΔHBS treatment exhibited high blood glucose level and elevated urine albumin-to-creatinine ratio. FGF1ΔHBS treatment effectively reversed hyperglycemia, delayed the development of renal dysfunction, and reduced kidney size and weight. Furthermore, FGF1ΔHBS treatment significantly prevented the progression of renal morphologic impairment. FGF1ΔHBS treatment demonstrated anti-inflammatory and anti-fibrotic effects, with significantly decreased protein levels of key pro-inflammatory cytokines and pro-fibrotic factors in kidney. Moreover, FGF1ΔHBS treatment greatly decreased apoptosis of renal tubular cells, accompanied by significant downregulation of the proapoptotic protein and upregulation of the antiapoptotic protein and peroxisome proliferator-activated receptor α (PPARα) expression in kidney. Mechanistically, FGF1ΔHBS treatment directly protected mouse proximal tubule cells against palmitate-induced apoptosis, which was abolished by PPARα inhibition. In conclusion, this study demonstrated that FGF1ΔHBS delays the progression of renal dysfunction likely through activating PPARα to prevent renal tubule cell death in late-stage T2D, exhibiting a promising translational potential in treating DN in elderly T2D individuals by ameliorating renal inflammation, fibrosis and apoptosis.

The Role of Platelets in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is among the most common microvascular complications in patients with diabetes, and it currently accounts for the majority of end-stage kidney disease cases worldwide. The pathogenesis of DKD is complex and multifactorial, including systemic and intra-renal inflammatory and coagulation processes. Activated platelets play a pivotal role in inflammation, coagulation, and fibrosis. Mounting evidence shows that platelets play a role in the pathogenesis and progression of DKD. The potentially beneficial effects of antiplatelet agents in preventing progression of DKD has been studied in animal models and clinical trials. This review summarizes the current knowledge on the role of platelets in DKD, including the potential therapeutic effects of antiplatelet therapies.

Rack1 regulates pro-inflammatory cytokines by NF-κB in diabetic nephropathy

Diabetic nephropathy (DN) is one of the chronic microvascular diseases of diabetes. Studies revealed that inflammation is involved in the development of DN. However, its mechanisms are not fully clear. Here, we screened DN-related mRNAs by RNA sequencing in the renal tissues of db/db DN mice and normal control mice. The Swiss-Model, ZDOCK 3.0.2 and PyMOL 2.3.2 were applied for bioinformatics analysis. In total, we obtained 6,820 mRNAs that were dysexpressed in DN. Among them, Receptor for Activated C Kinase 1 (Rack1) was focused on for its high fold changes and high values of fragments per kilobase million (FPKM) in both two groups (FPKM >100). Moreover, Rack1 was highly expressed in DN in vivo and in vitro. Results displayed that the expressions of pro-inflammatory cytokines Mcp-1 and Tnf-α were increased when Rack1 was overexpressed in cells cultured with low glucose while the expressions of Mcp-1 and Tnf-α were decreased when Rack1 was silenced in cells cultured with high glucose. Furthermore, results showed that the established DN inflammatory factor nuclear factor NF-kappa-B (NF-κB) was regulated by Rack1 via the direct interaction between Rack1 and NF-κB subunits P50 and P65. In summary, this identified Rack1 could play an important role in the inflammation of DN via NF-κB, which can provide new insight for DN research.

Mechanism of Cordyceps sinensis and its Extracts in the Treatment of Diabetic Kidney Disease: A Review

Diabetic kidney disease (DKD) is the major reason of chronic kidney disease (CKD)-caused end-stage renal failure (ESRF), and leads to high mortality worldwide. At present, the treatment of DKD is mainly focused on controlling the hyperglycemia, proteinuria, and hypertension, but is insufficient on the effective delay of DKD progression. Cordyceps sinensis is a kind of wild-used precious Chinese herb. Its extracts have effects of nephroprotection, hepatoprotection, neuroprotection, and protection against ischemia/reperfusion-induced injury, as well as anti-inflammatory and anti-oxidant activities. According to the theory of traditional Chinese medicine, Cordyceps sinensis can tonify the lung and the kidney. Several Chinese patent medicines produced from Cordyceps sinensis are often used to treat DKD and achieved considerable efficacy. This review summarized the clinical usage of Cordyceps sinensis, as well as its mainly biological activities including anti-hyperglycemic, anti-inflammatory, immunomodulatory, anti-oxidant, anti-fibrotic activities and regulation of apoptosis.

Maresin 1 Alleviates Diabetic Kidney Disease via LGR6-Mediated cAMP-SOD2-ROS Pathway

BACKGROUND

Chronic hyperglycemia-induced inflammation is recognized as the most important pathophysiological process in diabetic kidney disease (DKD). As maresin 1 (MaR1) is an extensive anti-inflammatory lipid mediator, the present study investigated the protective role of MaR1 in the pathogenesis of DKD and its clinical relevance.

METHODS

Serum MaR1 concentrations were analyzed in 104 subjects with normal glucose tolerant, type 2 diabetes (T2DM), or DKD. Streptozotocin (STZ) together with high fat diet was used to induce male C57BL/6 J mice into diabetic mice which were treated with MaR1. Human renal tubule epithelial cells (HK-2 cells) were treated by high glucose for glucotoxicity cell model and transfected with LGR6 siRNA for knockdown with MaR1 added，and detected oxidative stress and inflammatory related factors.

RESULTS

Serum MaR1 concentrations were significant decreased in T2DM with or without kidney disease compared with normal participant and were lowest in patients with DKD. Serum MaR1 concentrations were negatively correlated with hemoglobin A1c (HbA1c), duration of diabetes, urinary albumin to creatinine ratio (UACR), neutrophil, and neutrophil-lymphocyte ratio and were positively correlated with high-density lipoprotein-cholesterol (HDL-C) and estimated glomerular filtration rate (eGFR). In mouse model, MaR1 injection alleviated hyperglycemia, UACR and the pathological progression of DKD. Interestingly, the renal expression of LGR6 was down-regulated in DKD and high glucose treated HK-2 cells but up-regulated by MaR1 treatment. Mechanistically, MaR1 alleviated inflammation via LGR6-mediated cAMP-SOD2 antioxidant pathway in DKD mice and high glucose treated HK-2 cells.

CONCLUSIONS

Our study demonstrates that decreased serum MaR1 levels were correlated with the development of DKD. MaR1 could alleviate DKD and glucotoxicity-induced inflammation via LGR6-mediated cAMP-SOD2 antioxidant pathway. Thus, our present findings identify MaR1 as a predictor and a potential therapeutic target for DKD.

STAT5A modulated EndMT via upregulation of ELTD1 expression in diabetic nephropathy

Diabetic nephropathy (DN), one of microvascular complications of diabetes mellitus, results in renal dysfunction and end-stage renal disease. Recently, endothelial-to-mesenchymal transition (EndMT) was reported to mediate glomerular endothelial dysfunction, thus participating in the progress of fibrosis in DN. As a special type of epithelial-to-mesenchymal transition, EndMT and epithelial-to-mesenchymal transition may share corporate modulators. It was reported that EGF, Latrophilin And Seven Transmembrane Domain Containing 1 (ELTD1) and signal transducer and activator of transcription 5A (STAT5A) participate in epithelial-to-mesenchymal transition in some situations. In this work, we proposed that STAT5A participated in high glucose-mediated EndMT via modulation of ELTD1 levels in DN. Our data indicated that hyperglycemia/high glucose-induced ELTD1 and EndMT in DN rats and hyperglycemic human glomerular endothelial cells (HGECs). Also, high glucose mediated STAT5A nuclear translocation in HGECs. Moreover, high glucose-mediated EndMT was reversed by ELTD1 silencing. Further, STAT5A was found to be elevated in DN rats and hyperglycemic HGECs. The effect of high glucose-mediated increase of ELTD1 expression and EndMT was reversed by STAT5A silencing in vitro. Further, STAT5A overexpression enhanced ELTD1 levels and EndMT, which was inhibited by si-ELTD1. ChIP and luciferase assay represented that STAT5A directly regulated ELTD1 transcription. STAT5A directly regulated ELTD1 transcription, thus participating in high glucose-mediated EndMT in glomeruli of DN. This article is protected by copyright. All rights reserved.

Histone lysine-specific demethylase 1 induced renal fibrosis via decreasing sirtuin 3 expression and activating TGF-β1/Smad3 pathway in diabetic nephropathy

OBJECTIVE

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. Histone lysine-specific demethylase 1 (LSD1) is a flavin-containing amino oxidase that can repress or activate transcription. The aim of this study is to explore the mechanism of LSD1 aggravating DN-induced renal fibrosis.

METHODS

The STZ-induced DN rat model was established for in vivo study. The rats were divided into four groups: Sham, STZ, STZ + Ad-shNC and Ad-shLSD1. The Hematoxylin-eosin (HE) staining was used to evaluate the renal injury. The Immunofluorescence assay was used to determine the LSD1, Fibronectin and α-SMA expression. The related protein expression was detected by western blot.

RESULTS

Knockdown of LSD1 alleviated STZ-induced renal injury. Moreover, knockdown of LSD1 decreased the expression of serum biochemical markers, containing urine output (24 h), urinary protein (24 h), serum creatinine, BUN and UACR. Furthermore, we proved that knockdown of LSD1 alleviated renal fibrosis in STZ-induced DN rats. In vitro, knockdown of LSD1 suppressed NRK-49F cells activation and overexpression of LSD1 induced renal fibrosis. In addition, knockdown of LSD1 could deactivate TGF-β1/Smad3 pathway and promote sirtuin 3 (SIRT3) expression in vivo and in vitro. The rescue experiments confirmed that LSD1 induced renal fibrosis via decreasing SIRT3 expression and activating TGF-β1/Smad3 pathway.

CONCLUSION

LSD1 deficiency leads to alleviate STZ-induced renal injury and overexpression of LSD1 induces renal fibrosis via decreasing SIRT3 expression and activating TGF-β1/Smad3 pathway, which provides a reasonable strategy for developing novel drugs targeting LDS1 to block renal fibrosis.

H19: A vital long noncoding RNA in the treatment of diabetes and diabetic complications

BACKGROUND

Increasing academic efforts have been made to explore the correlation of long noncoding RNAs (lncRNAs) with human diseases, particularly metabolic diseases like diabetes mellitus. Taking lncRNA H19 as an example, this review intends to reveal the functions and mechanism of lncRNA H19 in diabetes mellitus and diabetic complications.

METHODS

The research results associated with lncRNA H19 and diabetes mellitus are collected and summarized on PubMed.

CONCLUSION

LncRNA H19 is a potential instructive marker for the treatment of diabetes mellitus and diabetic complications.

Sitagliptin's renoprotective effect in a diabetic nephropathy model in rats: The potential role of PI3K/AKT pathway

Management of diabetic nephropathy (DN) is far from satisfactory. There is a rising role of the involvement of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in the pathogenesis of DN. This study aimed at investigating the renoprotective effects of PI3K/AKT pathway via sitagliptin in a rat model of DN. Thirty-two male Wistar rats were divided into four groups (eight rats each): (I) control, (II) sitagliptin, (III) DN, and (IV) DN + sitagliptin. Fasting blood glucose (FBG), kidney index, and kidney function tests in both blood and urine were measured. The levels of superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta (TGF-β) and gene expressions of PI3K, pPI3K, AKT, and pAKT in renal tissue were detected. Renal histopathological and immunohistochemical studies were evaluated. DN + sitagliptin group showed significant decrease in FBG and kidney index, improvement in kidney function tests, and a decrease in levels of TNF-α and TGF-β in renal tissues compared with DN group. This was associated with significant increase in SOD and gene expressions of PI3K and AKT and their phosphorylated active forms in renal tissue in DN + sitagliptin group compared with DN group. Moreover, DN + sitagliptin group showed apparent decrease in amount of collagen fibers and expression of alpha-smooth muscle actin (α-SMA) compared with DN group. This work shows that sitagliptin improved renal functions and histopathological changes, impeded inflammation, and oxidative stress and upregulated PI3K/AKT pathway which highlights its renoprotective effects in a rat model of DN.

Recent Advances in Diabetic Kidney Diseases: From Kidney Injury to Kidney Fibrosis

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease and end-stage renal disease. The natural history of DKD includes glomerular hyperfiltration, progressive albuminuria, declining estimated glomerular filtration rate, and, ultimately, kidney failure. It is known that DKD is associated with metabolic changes caused by hyperglycemia, resulting in glomerular hypertrophy, glomerulosclerosis, and tubulointerstitial inflammation and fibrosis. Hyperglycemia is also known to cause programmed epigenetic modification. However, the detailed mechanisms involved in the onset and progression of DKD remain elusive. In this review, we discuss recent advances regarding the pathogenic mechanisms involved in DKD.

α2-antiplasmin positively regulates endothelial-to-mesenchymal transition and fibrosis progression in diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN), is microvascular complication of diabetes causes to kidney dysfunction and renal fibrosis. It is known that hyperglycemia and advanced glycation end products (AGEs) produced by hyperglycemic condition induce myofibroblast differentiation and endothelial-to-mesenchymal transition (EndoMT), and exacerbate fibrosis in DN. Recently, we demonstrated that α2-antiplasmin (α2AP) is associated with inflammatory response and fibrosis progression.

METHODS

We investigated the role of α2AP on fibrosis progression in DN using a streptozotocin-induced DN mouse model.

RESULTS

α2AP deficiency attenuated EndoMT and fibrosis progression in DN model mice. We also showed that the high glucose condition/AGEs induced α2AP production in fibroblasts (FBs), and the reduction of receptor for AGEs (RAGE) by siRNA attenuated the AGEs-induced α2AP production in FBs. Furthermore, the bloackade of α2AP by the neutralizing antibody attenuated the high glucose condition-induced pro-fibrotic changes in FBs. On the other hand, the hyperglycemic condition/AGEs induced EndoMT in vascular endothelial cells (ECs), the FBs/ECs co-culture promoted the high glucose condition-induced EndoMT compared to ECs mono-culture. Furthermore, α2AP promoted the AGEs-induced EndoMT, and the blockade of α2AP attenuated the FBs/ECs co-culture-promoted EndoMT under the high glucose condition.

CONCLUSIONS

The high glucose conditions induced α2AP production, and α2AP is associated with EndoMT and fibrosis progression in DN. These findings provide a basis for clinical strategies to improve DN.

Long non-coding RNA TTC28-AS1 attenuates high glucose-induced damage in HK-2 cells depending on the regulation of miR-320a/CD2AP axis

BACKGROUND

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD) worldwide. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play crucial roles in DN pathogenesis.

OBJECTIVE

The purpose of the present study was to explore the role and mechanism of lncRNA tetratricopeptide repeat domain 2B antisense RNA 1 (TTC28-AS1) in DN.

METHODS

Cell viability and apoptosis were assessed by the Cell Counting-8 Kit (CCK-8) assay and flow cytometry, respectively. The levels of TTC28-AS1, miR-320a and CD2-associated protein (CD2AP) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-8 were gauged by enzyme-linked immunosorbent assay (ELISA). Targeted relationship between miR-320a and TTC28-AS1 or CD2AP was evaluated by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

Our data indicated that high glucose (HG) induced HK-2 cell damage by the repression of cell viability and autophagy and the enhancement of cell apoptosis, fibrosis and pro-inflammatory cytokines production. TTC28-AS1 was down-regulated and miR-320a was up-regulated in HG-induced HK-2 cells. TTC28-AS1 overexpression or miR-320a knockdown alleviated HG-induced damage in HK-2 cells. MiR-320 was a molecular mediator of TTC28-AS1 in regulating HG-induced HK-2 cell damage. Moreover, TTC28-AS1 functioned as a post-transcriptional regulator of CD2AP expression by miR-320a. MiR-320a knockdown relieved HG-induced damage in HK-2 cells by up-regulating CD2AP.

CONCLUSIONS

Our findings suggest that TTC28-AS1 attenuates HG-induced damage in HK-2 cells at least partially by targeting the miR-320a/CD2AP axis, highlighting its role as a promising therapeutic approach for DN treatment.

Development of Biomarkers and Molecular Therapy Based on Inflammatory Genes in Diabetic Nephropathy

Diabetic Nephropathy (DN) is a debilitating consequence of both Type 1 and Type 2 diabetes affecting the kidney and renal tubules leading to End Stage Renal Disease (ESRD). As diabetes is a world epidemic and almost half of diabetic patients develop DN in their lifetime, a large group of people is affected. Due to the complex nature of the disease, current diagnosis and treatment are not adequate to halt disease progression or provide an effective cure. DN is now considered a manifestation of inflammation where inflammatory molecules regulate most of the renal physiology. Recent advances in genetics and genomic technology have identified numerous susceptibility genes that are associated with DN, many of which have inflammatory functions. Based on their role in DN, we will discuss the current aspects of developing biomarkers and molecular therapy for advancing precision medicine.

Rosiglitazone attenuates high glucose-induced proliferation, inflammation, oxidative stress and extracellular matrix accumulation in mouse mesangial cells through the Gm26917/miR-185-5p pathway

Rosiglitazone (RSG) is widely used to reduce the amount of sugar in the blood of patients with diabetes mellitus. Diabetic nephropathy is the most common microvascular complication of diabetes. The role of RSG in diabetic nephropathy is not fully understood. Diabetic nephropathy model was constructed in high glucose (HG)-treated mouse mesangial cells. The effects of RSG on cell viability and cell cycle were investigated using cell counting kit-8 (CCK-8) assay and flow cytometry assay. Oxidative stress was assessed according to ROS production and SOD activity in cells. Inflammatory responses were assessed according to the releases of inflammatory cytokines. Extracellular matrix (ECM) accumulation was determined by the levels of fibronectin and collagen IV using western blot. The expression of Gm26917 and microRNA-185-5p (miR-185-5p) was detected by quantitative real-time polymerase chain reaction (qPCR). The interaction between Gm26917 and miR-185-5p was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and pull-down assay. RSG significantly inhibited HG-induced proliferation, oxidative stress, inflammatory responses and ECM accumulation in mouse mesangial cells. The expression of Gm26917 was induced by HG but weakened by RSG. Gm26917 knockdown alleviated HG-induced proliferation, oxidative stress, inflammatory responses and ECM accumulation in mouse mesangial cells, and Gm26917 overexpression partly abolished the effects of RSG. Moreover, miR-185-5p was a target of Gm26917, and miR-185-5p inhibition recovered proliferation, oxidative stress, inflammatory responses and ECM accumulation in mouse mesangial cells that were alleviated by Gm26917 knockdown. RSG ameliorated HG-induced mouse mesangial cell proliferation, oxidative stress, inflammation and ECM accumulation partially by governing the Gm26917/miR-185-5p pathway.

Early Renoprotective Effect of Ruxolitinib in a Rat Model of Diabetic Nephropathy

Diabetic kidney disease (DKD) is still one of the unresolved major complications of diabetes mellitus, which leads ultimately to end-stage renal disease in both type 1 and type 2 diabetes patients. Available drugs that suppress the renin-angiotensin system have partially minimized the disease impact. Yet, there is an unmet need for new therapeutic interventions to protect the kidneys of diabetic patients. In DN, glomerular sclerosis and tubulointerstitial fibrosis are mediated through several pathways, of which JAK/STAT is a key one. The current study explored the potential renoprotective effect of the JAK1/JAK2 inhibitor ruxolitinib (at doses of 0.44, 2.2, and 4.4 mg·kg-1) compared to that of enalapril at a dose of 10 mg·kg-1, in a rat model of streptozotocin-induced diabetes mellitus over 8 weeks. The effect of ruxolitinib was assessed by determining urinary albumin/creatinine ratio, serum level of cystatin, and levels of TGF-β1, NF-κB, and TNF-α in renal tissue homogenates by biochemical assays, the glomerular sclerosis and tubulointerstitial fibrosis scores by histological analysis, and fibronectin, TGF-β1, and Vimentin levels by immunohistochemical staining with the respective antibodies. Our results revealed a significant early favorable effect of a two-week ruxolitinib treatment on the renal function, supported by a decline in the proinflammatory biomarkers of DKD. This pre-clinical study suggests that the renoprotective effect of ruxolitinib in the long term should be investigated in animals, as this drug may prove to be a potential option for the treatment of diabetic kidney disease.

Juglanin protects against high fat diet-induced renal injury by suppressing inflammation and dyslipidemia via regulating NF-κB/HDAC3 signaling

Obesity is an important factor implicated in chronic kidney disease (CKD). Juglanin (Jug) is a natural compound extracted from the crude Polygonumaviculare, showing anti-inflammatory and anti-diabetic effects. However, whether Jug has protective effects against obesity-induced renal injury, little has been investigated. Herein, we attempted to explore the potential of Jug in mediating obesity-induced kidney disease in high fat diet (HFD)-challenged mice. Our results suggested that chronic HFD feeding markedly increased the body weights of mice compared to the ones fed with normal chow diet (NCD), along with significant glucose intolerance and insulin resistance. However, these metabolic disorders induced by HFD were effectively alleviated by Jug treatments in a dose-dependent manner. Moreover, HFD-challenged mice showed apparent histopathological changes in renal tissues with significant collagen accumulation, which were attenuated by Jug supplementation. In addition, Jug treatment decreased the expression levels of kidney injury molecule-1 (KIM-1), while increased nephrin and podocin expression levels in kidney of HFD-challenged mice, improving the renal dysfunction. Furthermore, HFD led to lipid deposition in kidney samples of mice by enhancing abnormal lipid metabolism. In addition, HFD promoted the releases of circulating pro-inflammatory cytokines, and enhanced the renal inflammation by activating nuclear factor-kappa B/histone deacetylase 3 (NF-κB/HDAC3) signaling. HFD-induced dyslipidemia and inflammation were considerably abrogated by Jug administration in mice. The protective effects of Jug against renal injury were confirmed in palmitate (PA)-stimulated HK2 cells in vitro mainly through suppressing the nuclear translocation of NF-κB and HDAC3, repressing inflammation and lipid accumulation eventually. Hence, Jug could ameliorate HFD-induced kidney injury mainly through blocking the NF-κB/HDAC3 nuclear translocation.

Both Specific Endothelial and Proximal Tubular Adam17 Deletion Protect against Diabetic Nephropathy

ADAM17 is a disintegrin and metalloproteinase capable of cleaving the ectodomains of a diverse variety of molecules including TNF-α, TGF-α, L-selectin, and ACE2. We have previously demonstrated that renal ADAM17 is upregulated in diabetic mice. The role of endothelial (eAdam17) and proximal tubular (tAdam17) Adam17 deletion in renal histology, modulation of the renin angiotensin system (RAS), renal inflammation, and fibrosis was studied in a mouse model of type 1 Diabetes Mellitus. Moreover, the effect of Adam17 deletion in an in vitro 3D cell culture from human proximal tubular cells under high glucose conditions was evaluated. eAdam17 deletion attenuates renal fibrosis and inflammation, whereas tAdam17 deletion decreases podocyte loss, attenuates the RAS, and decreases macrophage infiltration, α-SMA and collagen accumulation. The 3D in vitro cell culture reinforced the findings obtained in tAdam17KO mice with decreased fibrosis in the Adam17 knockout spheroids. In conclusion, Adam17 deletion either in the endothelial or the tubular cells mitigates kidney injury in the diabetic mice by targeting different pathways. The manipulation of Adam17 should be considered as a therapeutic strategy for treating DN.

lncRNA MALAT1 Promotes Renal Fibrosis in Diabetic Nephropathy by Targeting the miR-2355-3p/IL6ST Axis

Long noncoding RNA (lncRNAs) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported in diabetic nephropathy (DN) about its effect on podocyte function and cell heat shock induced by hyperglycemia. However, the biological mechanism of MALAT1 regulating DN fibrosis needs further study. In this study, SD rats were administrated with streptozotocin (STZ) to establish a diabetes model. In vitro, human renal tubular epithelial cells (HK-2 and 293T) were treated with high glucose (HG). Here, we found that MALAT1 was upregulated in renal tissues of diabetic rats and HG-treated cells, and HG treatment promoted cell proliferation and invasion. MALAT1 overexpression aggravated protein levels of collagen I (col I), collagen IV (col IV), fibronectin (FN), and laminin (LN) in HK-2 cells, while MALAT1 knockdown exerted the opposite effect. Moreover, the luciferase reporter gene and pull-down assays demonstrated that MALAT1 interacted with miR-2355-3p. The miR-2355-3p level was downregulated in diabetic rats and HG-treated cells, and MALAT1 overexpression inhibited the miR-2355-3p level. Bioinformatics prediction and luciferase reporter gene assay revealed that interleukin 6 signal transducer (IL6ST) was a target of miR-2355-3p. In addition, miR-2355-3p overexpression attenuated fibrosis-related gene levels in HG-treated cells by inhibiting IL6ST expression and inactivating the recombinant signal transducer and activator of the transcription 3 (STAT3) signaling pathway. Knockdown of miR-2355-3p reversed the inhibitory effect of MALAT1 knockdown on IL6ST, col I, col IV, FN, and LN protein levels in HG-induced cells. Overexpression of MALAT1 aggravated cell damage in HG-induced cells via the miR-2355-3p/IL6ST/STAT3 signaling pathway. Finally, enhanced renal fibrosis and kidney tissue damage were observed in diabetic rats. In conclusion, MALAT1 overexpression may enhance renal fibrosis in diabetic rats and cell damage in HG-induced HK-2 cells via the miR-2355-3p/IL6ST axis, which provides a new perspective of DN treatment.

MiR-1297 attenuates high glucose-induced injury in HK-2 cells via targeting COL1A2

BACKGROUND

In this study, we aimed to explore whether COL1A2 and miR-1297 participated in the progression of diabetic nephropathy (DN) in vitro and classified the underlying mechanisms.

METHODS

d-Glucose (30 mM; high glucose, HG)-stimulated HK-2 cells were used to mimic DN condition. RNA and non-coding RNA profiles were from Gene Expression Omnibus (GEO) database. The interaction between miR-1297 and COL1A2 was measured by dual-luciferase reporter assay. Gene Set Enrichment Analysis (GSEA) method was conducted to analyse COL1A2-associated signalling pathways. The role of miR-1297/COL1A2 in biological behaviours of HG-induced HK-2 cells were analysed by cell counting kit-8 and apoptosis assays.

RESULTS

Bioinformatics analysis revealed that COL1A2 was up-regulated in DN tissues. We predicted and verified miR-1297 as the regulatory miRNA of COL1A2, and the expression of miR-1297 was decreased in DN tissues and HG-stimulated HK-2 cells. Overexpression of miR-1297 could promote cell proliferation and inhibit apoptosis to protect HK-2 cells from HG-induced damage. And knockdown of COL1A2 enhanced the protective effects of miR-1297 on HG-stimulated HK-2 cells. GSEA results revealed that several inflammatory pathways were enriched in COL1A2 high-expression group. Meanwhile, transfection of miR-1297 reduced the phosphorylation of NFκB and expression of three important pro-inflammatory genes including cytokine CCL5, adhesion molecules ICAM1 and VCAM1 via targeting COL1A2. These results suggested that miR-1297 protected HG-treated HK-2 cells probably through suppressing inflammation via targeting COL1A2.

CONCLUSION

This study sheds a light on the role miR-1297/COL1A2 in DN progression and provides a novel promising therapy strategy for suppressing DN progression.

Role of Thioredoxin-Interacting Protein in Diseases and Its Therapeutic Outlook

Thioredoxin-interacting protein (TXNIP), widely known as thioredoxin-binding protein 2 (TBP2), is a major binding mediator in the thioredoxin (TXN) antioxidant system, which involves a reduction-oxidation (redox) signaling complex and is pivotal for the pathophysiology of some diseases. TXNIP increases reactive oxygen species production and oxidative stress and thereby contributes to apoptosis. Recent studies indicate an evolving role of TXNIP in the pathogenesis of complex diseases such as metabolic disorders, neurological disorders, and inflammatory illnesses. In addition, TXNIP has gained significant attention due to its wide range of functions in energy metabolism, insulin sensitivity, improved insulin secretion, and also in the regulation of glucose and tumor suppressor activities in various cancers. This review aims to highlight the roles of TXNIP in the field of diabetology, neurodegenerative diseases, and inflammation. TXNIP is found to be a promising novel therapeutic target in the current review, not only in the aforementioned diseases but also in prolonged microvascular and macrovascular diseases. Therefore, TXNIP inhibitors hold promise for preventing the growing incidence of complications in relevant diseases.

PTPN14 deficiency alleviates podocyte injury through suppressing inflammation and fibrosis by targeting TRIP6 in diabetic nephropathy

Diabetic nephropathy (DN) is a common complication of diabetes, and a leading cause of end-stage renal disease. However, the pathogenesis that contributes to DKD is still not fully understood. Protein tyrosine phosphatase non-receptor type 14 (PTPN14), a non receptor tyrosine phosphatase, has numerous cellular events, such as inflammation and cell death. But its potential on DKD has not been investigated yet. In this study, we found that PTPN14 expression was markedly up-regulated in kidney samples of DKD patients, which were confirmed in diabetic mice and were clearly localized in glomeruli. The diabetic mouse model was established using streptozotocin (STZ) in wild type (WT) or PTPN knockout (KO) mice. After, STZ challenge, STZ mice displayed improved kidney functions. The results also showed that STZ-induced histological changes and podocyte injury in renal tissues, which were effectively alleviated by PTPN14 deletion. Moreover, PTPN14 deficiency significantly mitigated inflammatory response and fibrosis in glomeruli of STZ-challenged mice through restraining the activation of nuclear factor-κB (NF-κB) and transforming growth factor (TGF)-β1 signaling pathways, respectively. The inhibitory effects of PTPN14 suppression on inflammation and fibrosis were confirmed in high glucose (HG)-incubated podocytes. We further found that thyroid receptor interactor protein 6 (TRIP6) expression was dramatically up-regulated in glomeruli of STZ-challenged mice, and was abolished by PTPN14 deletion, which was confirmed in HG-treated podocytes with PTPN14 knockdown. Intriguingly, our in vitro studies showed that PTPN14 directly interacted with TRIP6. Of note, over-expressing TRIP6 markedly abrogated the effects of PTPN14 silence to restrict inflammatory response and fibrosis in HG-incubated podocytes. Taken together, our findings demonstrated that targeting PTPN14 may provide feasible therapies for DKD treatment.

Nephroprotective Effect of Adropinin Against Streptozotocin-Induced Diabetic Nephropathy in Rats: Inflammatory Mechanism and YAP/TAZ Factor

BACKGROUND

Diabetic Nephropathy remains a major cause of morbidity and mortality in patients suffering from renal dysfunction. This study accessed the nephroprotective role of Adropinin against streptozotocin (STZ) induced diabetic nephropathy in rats and scrutinizes the possible mechanism of action.

METHODS

STZ (45 mg/kg) dose was used for inducing diabetic nephropathy (DN) and rats were divided into different groups and received the dose-dependent treatment of Adropinin. Blood glucose level, body weight, tissue weight, antioxidant, renal, hepatic parameters, and cytokines were determined. At the end of the experimental study, renal histopathology was performed.

RESULTS

Adropinin significantly (P<0.001) boosted plasma insulin levels and reduced the blood glucose level. Adropinin considerably increased body weight and reduced kidney weight and kidney hypertrophy. Adropinin significantly (P<0.001) reduced urine outflow, microalbumin, total protein, blood urea nitrogen (BUN), uric acid and increased the creatinine, creatinine clearance. Adropinin significantly (P<0.001) reduced the indole sulfate level in the serum, kidney and reduced in the urine. Adropinin significantly (P<0.001) reduced the total cholesterol, triglyceride, low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL) and increased the level of high-density lipoprotein (HDL). Adropinin significantly (P<0.001) increased the level of antioxidant enzymes such as glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and reduced the level of malonaldehyde (MDA), 8-hydroxy-2' -deoxyguanosine (8-OHdG). Adropinin significantly (P<0.001) reduced the level of interleukin-1β (IL-1β), interleukin-6 (IL-6), transforming growth factor beta (TGF-β) and increased the level of interleukin-10 (IL-10), respectively. Adropinin treatment showed improvement in renal histopathology.

CONCLUSION

We can say that Adropinin showed the nephroprotective effect against the STZ-induced diabetic nephropathy rats via inflammatory and antioxidant pathway.

JAB1 Promotes High Glucose-Induced Inflammation and Extracellular Matrix Deposition in Glomerular Mesangial Cells by Regulating Angiopoietin-Like Protein 2

Diabetic or hyperglycaemic conditions stimulate the inflammatory response, excessive accumulation of extracellular matrix, and result in glomerulosclerosis, a scarring process of diabetic nephropathy. c-Jun activation domain-binding protein 1 (JAB1) functions as a regulator of pathways involved in cellular apoptosis and proliferation. The role of JAB1 in diabetic nephropathy was investigated in this study. Firstly, glomerular mesangial cells (GMCs) were treated with high glucose, and high glucose conditions induced up-regulation of JAB1 in the GMCs. Moreover, IL-6, TNF-α, MCP-1, and IL-1β were also elevated in high glucose-induced GMCs. Secondly, silencing of JAB1 reduced the levels of IL-6, TNF-α, MCP-1, and IL-1β in high glucose-induced GMCs. In addition, silencing of JAB1 attenuated the high glucose-induced decrease of superoxide dismutase (SOD) and the increase of reactive oxygen species (ROS) and malondialdehyde (MDA). The increased TGF-β1, collagen I, collagen IV, and fibronectin levels in high glucose-induced GMCs were restored by knockdown of JAB1. Thirdly, angiopoietin-like protein 2 (ANGPTL2) expression was reduced by JAB1. Over-expression of ANGPTL2 weakened the JAB1 silence-induced decrease of IL-6, TNF-α, MCP-1, IL-1β, TGF-β1, collagen I, collagen IV, and fibronectin. In conclusion, silencing of JAB1 reduced extracellular matrix deposition and suppressed inflammation in high glucose-induced GMCs through down-regulation of ANGPTL2.

Knockdown of LncRNA-H19 Ameliorates Kidney Fibrosis in Diabetic Mice by Suppressing miR-29a-Mediated EndMT

Diabetic nephropathy is the leading cause of kidney fibrosis. Recently, altered expressed or dysfunction of some long non-coding RNAs (lncRNAs) has been linked to kidney fibrosis; however, the mechanisms of lncRNAs in kidney fibrosis remain unclear. We have shown that the DPP-4 inhibitor linagliptin can inhibit endothelial-mesenchymal transition (EndMT) and ameliorate diabetic kidney fibrosis associated with DPP-4 protein levels via the induction of miR-29. Here, we found that expression of the lncRNA H19 was significantly up-regulated in TGF-β2-induced fibrosis in human dermal microvascular endothelial cells (HMVECs) in vitro, and in kidney fibrosis of streptozotocin-induced diabetic CD-1 mice. We also detected up-regulated H19 expression and down-regulated miR-29a expression in the early and advanced mouse models of diabetic kidney fibrosis. H19 knockdown significantly attenuated kidney fibrosis in vitro and in vivo, which was associated with the inhibition of the EndMT-associated gene FSP-1. We also found that the up-regulation of H19 observed in fibrotic kidneys associated with the suppression of miR-29a in diabetic mice. H19, miR-29a, and EndMT contribute to a regulatory network involved in kidney fibrosis, and are associated with regulation of the TGF-β/SMAD3 singling pathway. This study indicates that inhibition of LncRNA H19 represents a novel anti-fibrotic treatment for diabetic kidney diseases.

Naringin attenuates renal interstitial fibrosis by regulating the TGF-β/Smad signaling pathway and inflammation

Interstitial fibrosis is a typical feature of all progressive renal diseases. The process of fibrosis is frequently coupled with the presence of pro-fibrotic factors and inflammation. Naringin is a dihydroflavone compound that has been previously reported to exhibit anti-fibrotic effects in the liver, where it prevents oxidative damage. In the present study, a rat model of renal interstitial fibrosis and fibrosis cell model were established to evaluate the effects of naringin on inflammatory proteins and fibrosis markers in kidney of rats and NRK-52E cells, and to elucidate the role of the TGF-β/Smad signaling pathway in this mechanism. Compared with those in fibrotic NRK-52E cells that were stimulated by transforming growth factor-β (TGF-β), gene expression levels of α-smooth muscle actin (α-SMA), collagen 1 (COL1A1), collagen 3 (COL3A1), interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) were all found to be significantly decreased in fibrotic NRK-52E cells following treatment with naringin (50, 100 and 200 ng/ml). Results from the histopathological studies showed that naringin treatment preserved the renal tissue structure and reduced the degree of fibrosis in the kidney tissues of rats that underwent unilateral ureteral obstruction (UUO). In addition, naringin administration reduced the expression of α-SMA, COL1A1, COL3A1, IL-1β, IL-6 and TNF-α in the kidneys of rats following UUO. The current study, using western blot analysis, indicated that naringin also downregulated the activation of Smad2/3 and the expression of Smad4, high-mobility group protein B1, activator protein-1, NF-κB and cyclooxygenase-2 whilst upregulating the expression of Smad7 in fibrotic NRK-52E cells and rats in the UUO group. In conclusion, naringin could antagonize renal interstitial fibrosis by regulating the TGF-β/Smad pathway and the expression of inflammatory factors.

NF-κB activation persists into the remodeling phase of tendon healing and promotes myofibroblast survival

Although inflammation is necessary during the early phases of tissue repair, persistent inflammation contributes to fibrosis. Acute tendon injuries often heal through a fibrotic mechanism, which impedes regeneration and functional recovery. Because inflammation mediated by nuclear factor κB (NF-κB) signaling is implicated in this process, we examined the spatial, temporal, and cell type-specific activation profile of canonical NF-κB signaling during tendon healing. NF-κB signaling was maintained through all phases of tendon healing in mice, including the remodeling phase, and tenocytes and myofibroblasts from the Scleraxis (Scx) lineage were the predominant populations that retained NF-κB activation into the late stages of repair. We confirmed persistent NF-κB activation in myofibroblasts in human tendon scar tissue. Deleting the canonical NF-κB kinase, IKKβ, in Scx-lineage cells in mice increased apoptosis and the deposition of the matrix protein periostin during the late stages of tendon repair, suggesting that persistent NF-κB signaling may facilitate myofibroblast survival and fibrotic progression. Consistent with this, myofibroblasts in human tendon scar samples displayed enhanced prosurvival signaling compared to control tissue. Together, these data suggest that NF-κB may contribute to fibrotic tendon healing through both inflammation-dependent and inflammation-independent functions, such as NF-κB-mediated cell survival.