TGF-β1/Smads and miR-21 in Renal Fibrosis and Inflammation

MicroRNA regulation in blood cells of renal transplanted patients with interstitial fibrosis/tubular atrophy and antibody-mediated rejection

Interstitial fibrosis/tubular atrophy (IFTA) is associated with reduced allograft survival, whereas antibody-mediated rejection (ABMR) is the major cause for renal allograft failure. To identify specific microRNAs and their regulation involved in these processes, total RNA from blood cells of 16 kidney transplanted (KTx) patients with ABMR, stable graft function (SGF) and with T-cell mediated rejection (TCMR) was isolated. MicroRNA expression was determined by high-throughput sequencing. Differentially expressed candidate microRNAs were analyzed with RT-PCR in patients with SGF (n = 53), urinary tract infection (UTI) (n = 17), borderline rejection (BL) (n = 19), TCMR (n = 40), ABMR (n = 22) and IFTA (n = 30). From the 301 detected microRNAs, 64 were significantly regulated between the three cohorts. Selected candidate microRNAs miR-223-3p, miR-424-3p and miR-145-5p distinguished TCMR and ABMR from SGF, but not from other pathologies. Most importantly, miR-145-5p expression in IFTA patients was significantly downregulated and displayed a high diagnostic accuracy compared to SGF alone (AUC = 0.891) and compared to SGF, UTI, BL, TCMR and ABMR patients combined (AUC = 0.835), which was verified by cross-validation. The identification of miR-145-5p as IFTA specific marker in blood constitutes the basis for evaluating this potentially diagnostic microRNA as biomarker in studies including high numbers of patients and different pathologies and also the further analysis of fibrosis causing etiologies after kidney transplantation.

Astragaloside IV improves renal function and fibrosis via inhibition of miR-21-induced podocyte dedifferentiation and mesangial cell activation in diabetic mice

Background

Podocyte dedifferentiation and mesangial cell (MC) activation play an important role in many glomerular diseases associated with fibrosis. MicroRNA-21 (miR-21) is closely linked to renal fibrosis, but it is unknown whether and how miR-21 promotes podocyte dedifferentiation and MC activation and whether astragaloside IV (AS-IV) improves renal function and fibrosis through the regulation of miR-21.

Materials and methods

Cultured MCs, primary mouse podocytes, and diabetic KK-Ay mice were treated with AS-IV. Cell transfection, Western blot, real-time PCR, immunofluorescence assay, immunohistochemical assay, and electronic microscopy were used to detect the markers of podocyte dedifferentiation and MC activation and to observe the renal morphology.

Results

Our data showed that miR-21 expression was increased and that AS-IV decreased miR-21 levels in cells, serum, and kidney. Overexpressed miR-21 promoted podocyte dedifferentiation and MC activation, and treatment with AS-IV reversed this effect. Furthermore, the overexpression of miR-21 activated the β-catenin pathway and the transforming growth factor (TGF)-β1/Smads pathway in the process of podocyte dedifferentiation and MC activation, which was abolished by AS-IV treatment. In addition, both the Wnt/β-catenin pathway inhibitor XAV-939 and the TGF-β1/Smads pathway inhibitor SB431542 reversed the effect of AS-IV. Furthermore, AS-IV improved renal function and fibrosis in diabetic KK-Ay mice.

Conclusion

Our results indicated that AS-IV ameliorates renal function and renal fibrosis by inhibiting miR-21 overexpression-induced podocyte dedifferentiation and MC activation in diabetic kidney disease. These findings pave way for future studies investigating AS-IV as a potential therapeutic agent in the management of glomerular diseases.

New insights into TGF-β/Smad signaling in tissue fibrosis

Transforming growth factor-β1 (TGF-β1) is considered as a crucial mediator in tissue fibrosis and causes tissue scarring largely by activating its downstream small mother against decapentaplegic (Smad) signaling. Different TGF-β signalings play different roles in fibrogenesis. TGF-β1 directly activates Smad signaling which triggers pro-fibrotic gene overexpression. Excessive studies have demonstrated that dysregulation of TGF-β1/Smad pathway was an important pathogenic mechanism in tissue fibrosis. Smad2 and Smad3 are the two major downstream regulator that promote TGF-β1-mediated tissue fibrosis, while Smad7 serves as a negative feedback regulator of TGF-β1/Smad pathway thereby protects against TGF-β1-mediated fibrosis. This review presents an overview of the molecular mechanisms of TGF-β/Smad signaling pathway in renal, hepatic, pulmonary and cardiac fibrosis, followed by an in-depth discussion of their molecular mechanisms of intervention effects both in vitro and in vivo. The role of TGF-β/Smad signaling pathway in tumor or cancer is also discussed. Additionally, the current advances also highlight targeting TGF-β/Smad signaling pathway for the prevention of tissue fibrosis. The review reveals comprehensive pathophysiological mechanisms of tissue fibrosis. Particular challenges are presented and placed within the context of future applications against tissue fibrosis.

MicroRNA-21 and microRNA-146a negatively regulate the secondary inflammatory response of microglia after intracerebral hemorrhage

BACKGROUND

A secondary inflammatory response is the most important mechanism of injury after intracerebral hemorrhage (ICH). Previous studies found microRNAs (miRs) expressed abnormally in the perihematomal tissue and blood of patients with ICH and demonstrated that miRs were related to pathophysiological changes and prognosis after ICH, and the development of inflammation.

METHODS

We induced a microglial inflammatory response by lipopolysaccharide (LPS) to construct a microglial inflammatory model. MiR-21/miR-146a overexpression adenovirus was used to infect microglia to increase miR-21/miR-146a expression. MiR-21, miR-146a, IRAK1, MMP-9, TNF-α, TIMP3 and other inflammatory factors were analyzed. Then, miR-21/miR-146a overexpression adenovirus was injected into rats with ICH to modulate the expression. Inflammation, brain edema, and neurological scores were assessed.

RESULTS

For in vitro and vivo experiments, overexpression of miR-21/miR-146a decreased the expression of IL-1β, IL-6, IL-8, IRAK1, MMP-9 and TNF-α, meanwhile increased the expression of TIMP3 significantly (P<0.001), compared with the negative control group. Additionally, miR-21 and miR-146a reduced brain edema and improved the neurological function in ICH rats.

CONCLUSION

Our study proved that miR-21 and miR-146a could negatively regulate the inflammatory response of microglia after ICH and provided a new theoretical basis for the treatment of secondary inflammatory injury after ICH in humans.

miR-21 Protects Against Ischemia/Reperfusion-Induced Acute Kidney Injury by Preventing Epithelial Cell Apoptosis and Inhibiting Dendritic Cell Maturation

Renal tubular injury and innate immune responses induced by hypoxia contribute to acute kidney injury. Accumulating evidence suggests that miR-21 overexpression protects against kidney ischemia injury. Additionally, miR-21 emerges as a key inhibitor in dendritic cell maturation. Thus, we hypothesized that miR-21 protects the kidney from IR injury by suppressing epithelial cell damage and inflammatory reaction. In this study, we investigated effects of miR-21 and its signaling pathways (PTEN/AKT/mTOR/HIF, PDCD4/NFκ-B) on kidney ischemia/reperfusion (IR) injury in vitro and in vivo. The results revealed that IR increased miR-21, HIF1α, and 2α expression in vivo and in vitro. MiR-21 interacted with HIF1α and 2α through the PTEN/AKT/mTOR pathway. Moreover, inhibition of miR-21 activated PDCD4/NFκ-B pathways, which are critical for dendritic cell maturation. Renal IR triggers local inflammation by inducing the dendritic cell maturation and promoting the secretion of IL-12, IL-6, and TNF-α cytokines. Knockdown of miR-21 intensified the effect of IR on tubular epithelial cell apoptosis and dendritic cell maturation. Our results suggested that IR-inducible miR-21 protects epithelial cells from IR injury via a feedback interaction with HIF (PTEN/AKT/mTOR/HIF/miR-21) and by inhibiting maturation of DCs through the PDCD4/NF-κB pathway. These findings highlight new therapeutic opportunities in AKI.

miR-21 promotes cardiac fibroblast-to-myofibroblast transformation and myocardial fibrosis by targeting Jagged1

Myocardial fibrosis after myocardial infarction (MI) is a leading cause of heart diseases. MI activates cardiac fibroblasts (CFs) and promotes CF to myofibroblast transformation (CMT). This study aimed to investigate the role of miR‐21 in the regulation of CMT and myocardial fibrosis. Primary rat CFs were isolated from young SD rats and treated with TGF‐β1, miR‐21 sponge or Jagged1 siRNA. Cell proliferation, invasion and adhesion were detected. MI model was established in male SD rats using LAD ligation method and infected with recombinant adenovirus. The heart function and morphology was evaluated by ultrasonic and histological analysis. We found that TGF‐β1 induced the up‐regulation of miR‐21 and down‐regulation of Jagged1 in rat CFs. Luciferase assay showed that miR‐21 targeted 3′‐UTR of Jagged1 in rat CFs. miR‐21 sponge inhibited the transformation of rat CFs into myofibroblasts, and abolished the inhibition of Jagged1 mRNA and protein expression by TGF‐β1. Furthermore, these effects of miR‐21 sponge on rat CFS were reversed by siRNA mediated knockdown of Jagged1. In vivo, heart dysfunction and myocardial fibrosis in MI model rats were partly improved by miR‐21 sponge but were aggravated by Jagged1 knockdown. Taken together, these results suggest that miR‐21 promotes cardiac fibroblast‐to‐myofibroblast transformation and myocardial fibrosis by targeting Jagged1. miR‐21 and Jagged1 are potential therapeutic targets for myocardial fibrosis.

Inhibition of VEGF gene expression in osteoblast cells by different NSAIDs

OBJECTIVE

To determine the effect of different nonsteroidal anti-inflammatory drugs (NSAIDs) on vascular endothelial growth factor (VEGF) gene expression in two osteoblast cell populations.

DESIGN

Osteoblasts obtained by primary culture (HOp) and human osteosarcoma cell line MG63 (MG-63), which were treated with 10 μM doses of acetaminophen, indomethacin, ketoprofen, diclofenac, ibuprofen, ketorolac, naproxen or piroxicam. At 24 h of treatment, their gene expression of VEGF was evaluated by real-time polymerase chain reaction (RT-PCR) and compared with the expression in untreated cells (control group).

RESULTS

The treatment with the different NSAIDs significantly reduced VEGF expression regardless of the cell line and NSAID studied.

CONCLUSION

The results of this study suggest that these drugs may have undesirable effects on the osteoblast and its bone-forming capacity, given the effect of this growth factor on these cells. Further studies are warranted to determine their repercussions on bone tissue and to elucidate the cell signaling mechanism/s involved.

Decorin-Modified Umbilical Cord Mesenchymal Stem Cells (MSCs) Attenuate Radiation-Induced Lung Injuries via Regulating Inflammation, Fibrotic Factors, and Immune Responses

PURPOSE

To evaluate the therapeutic effects of decorin (DCN)-modified mesenchymal stem cells (MSCs) on radiation-induced lung injuries (RILIs) and to clarify the underlying mechanisms.

METHODS AND MATERIALS

Umbilical cord-derived mesenchymal stem cells (MSCs) were modified with Ad(E1-).DCN to generate DCN-expressing MSCs (DCN-modified MSCs [MSCs.DCN]). In an experimental mouse model of RILI, MSCs.DCN and MSCs.Null [MSCs modified with Ad(E1-).Null] were intravenously engrafted at 6 hours or 28 days after irradiation. The therapeutic effects on lung inflammation and fibrosis were evaluated by histopathologic analysis at 28 days and 3 months after irradiation. Inflammatory cytokines and chemokines were analyzed in both sera and lung tissues, and subtypes of T lymphocytes including regulatory T cells (Tregs) were analyzed in the peripheral blood and spleen.

RESULTS

Both MSC treatments could alleviate histopathologic injuries by reducing lymphocyte infiltration, decreasing apoptosis, increasing proliferation of epithelial cells, and inhibiting fibrosis in the later phase. However, treatment with MSCs.DCN resulted in much more impressive therapeutic effects. Moreover, we discovered that MSC treatment reduced the expression of chemokines and inflammatory cytokines and increased the expression of anti-inflammatory cytokines in both the peripheral blood and local pulmonary tissues. An important finding was that MSCs.DCN were much more effective in inducing interferon-γ expression, inhibiting collagen type III α1 expression in pulmonary tissues, and decreasing the proportion of Tregs. Furthermore, our data suggested that treatment during the acute phase (6 hours) after irradiation evoked much stronger responses both in attenuating inflammation and in inhibiting fibrosis than in the later phase (28 days).

CONCLUSIONS

MSCs.DCN could attenuate acute inflammation after irradiation and significantly inhibit later fibrosis. Likewise, DCN enhanced the functions of MSCs by targeting profibrotic factors and Tregs.

High circulatory leptin mediated NOX-2-peroxynitrite-miR21 axis activate mesangial cells and promotes renal inflammatory pathology in nonalcoholic fatty liver disease

High circulatory insulin and leptin followed by underlying inflammation are often ascribed to the ectopic manifestations in non-alcoholic fatty liver disease (NAFLD) but the exact molecular pathways remain unclear. We have shown previously that CYP2E1-mediated oxidative stress and circulating leptin in NAFLD is associated with renal disease severity. Extending the studies, we hypothesized that high circulatory leptin in NAFLD causes renal mesangial cell activation and tubular inflammation via a NOX2 dependent pathway that upregulates proinflammatory miR21. High-fat diet (60% kcal) was used to induce fatty liver phenotype with parallel insulin and leptin resistance. The kidneys were probed for mesangial cell activation and tubular inflammation that showed accelerated NASH phenotype and oxidative stress in the liver. Results showed that NAFLD kidneys had significant increases in α-SMA, a marker of mesangial cell activation, miR21 levels, tyrosine nitration and renal inflammation while they were significantly decreased in leptin and p47 phox knockout mice. Micro RNA21 knockout mice showed decreased tubular immunotoxicity and proinflammatory mediator release. Mechanistically, use of NOX2 siRNA or apocynin,phenyl boronic acid (FBA), DMPO or miR21 antagomir inhibited leptin primed-miR21-mediated mesangial cell activation in vitro suggesting a direct role of leptin-mediated NOX-2 in miR21-mediated mesangial cell activation. Finally, JAK-STAT inhibitor completely abrogated the mesangial cell activation in leptin-primed cells suggesting that leptin signaling in the mesangial cells depended on the JAK-STAT pathway. Taken together the study reports a novel mechanistic pathway of leptin-mediated renal inflammation that is dependent on NOX-2-miR21 axis in ectopic manifestations underlying NAFLD-induced co-morbidities.

Mutual regulation between miR-21 and the TGFβ/Smad signaling pathway in human bronchial fibroblasts promotes airway remodeling

OBJECTIVE

Airway remodeling is an important pathological feature of asthma. Excessive deposition of extracellular matrix (e.g., collagen) secreted from fibroblasts is a major factor contributing to airway remodeling. Currently, the mechanism by which collagen continues to be oversynthesized in the airway remains unclear. In this study, we investigated the role of the microRNA-21 (miR-21) and TGFβ/Smad signaling pathway in human bronchial fibroblasts (HBFs), and explored the regulatory mechanism of airway remodeling.

METHODS

HBFs were cultured in vitro and treated with the transforming growth factor β (TGFβ), receptor inhibitor (SB431542), and TGFβ1. miR-21 and Smad7 overexpressing lentiviruses, as well as an miR-21 interfering lentivirus were constructed and transfected into HBFs. Western blotting was used to determine the expression of airway remodeling-related proteins and proteins in the TGFβ/Smad signaling pathway. miR-21 expression was measured by quantitative real-time PCR.

RESULTS

The high expression of miR-21 induced by TGFβ1 was reduced following the treatment with the SB431542 in HBFs. Smad7 overexpression inhibited the elevated expression of the COL I protein induced by miR-21 overexpression in HBFs. Inhibiting miR-21 expression upregulated the level of Smad7 protein, thus reducing the expression of airway remodeling-related proteins induced by TGFβ1 stimulation in HBFs.

CONCLUSIONS

TGFβ1 can induce miR-21 expression in HBFs through the TGFβ/Smad signaling pathway to promote airway remodeling. miR-21 downregulates Smad7, activates the TGFβ/Smad signaling pathway, and promotes airway remodeling. Mutual regulation between miR-21 and the TGFβ/Smad signaling pathway in HBFs promotes airway remodeling.

miR‑152 regulates TGF‑β1‑induced epithelial‑mesenchymal transition by targeting HPIP in tubular epithelial cells

Renal fibrosis is a common pathological feature of chronic kidney diseases, and their development and progression are influenced by epigenetic modifications including aberrant microRNA (miRNA or miR) expression. miRNAs have been demonstrated to modulate the aggressiveness of various cancers and have emerged as possible therapeutic agents for the management of renal fibrosis. Transforming growth factor β1 (TGF‑β1)‑induced epithelial‑mesenchymal transition (EMT) of tubular epithelial cells serves a role in the initiation and progression of renal fibrosis. Furthermore, recent results indicated that the progression of EMT is reversible. The present study aimed to clarify the role of miR‑152 in EMT of the tubular epithelial cell line HK‑2, stimulated by TGF‑β1, using in vitro transfection with a miR‑152 mimic and to further investigate the underlying mechanism of miR‑152 activity. In the present study, miR‑152 expression was significantly reduced in TGF‑β1‑treated HK‑2 cells, accompanied by an increased expression of hematopoietic pre‑B‑cell leukemia transcription factor (PBX)‑interacting protein (HPIP). Additionally, miR‑152 overexpression inhibited TGF‑β1‑induced EMT and suppressed HPIP expression by directly targeting the 3' untranslated region of HPIP in HK‑2 cells. Furthermore, upregulation of HPIP reversed miR‑152‑mediated inhibitory effects on the EMT. Collectively, the results suggest that downregulation of miR‑152 initiates the dedifferentiation of renal tubules and progression of renal fibrosis, which may provide important targets for prevention strategies of renal fibrosis.

Human CD36 overexpression in renal tubules accelerates the progression of renal diseases in a mouse model of folic acid-induced acute kidney injury

Background

Acute kidney injury (AKI) is a risk factor for progression to chronic kidney disease, with even subclinical AKI episodes progressing to chronic kidney disease. Several risk factors such as preexisting kidney disease, hyperglycemia, and hypertension may aggravate renal disease after AKI. However, mechanisms underlying the progression of AKI are still unclear. This study identified the effect of human cluster of differentiation 36 (CD36) overexpression on the progression of folic acid-induced AKI.

Methods

Pax8-rtTA/tetracycline response element-human CD36 transgenic mice were used to elucidate the effect of human CD36 overexpression in the proximal tubules on folic acid-induced AKI.

Results

Results of histological analysis showed severely dilated tubules with casts and albuminuria in folic acid-treated transgenic mice overexpressing human CD36 compared with folic acid-treated wild-type mice. In addition, analysis of mRNA expression showed a significant increase in the collagen 3a1 gene in folic acid-treated transgenic mice overexpressing human CD 36 compared with folic acid-treated wild type mice.

Conclusion

Human CD36-overexpressing transgenic mice showed severe pathological changes and albuminuria compared with wild-type mice. Moreover, mRNA expression of the collagen 3a1 gene increased in folic acid-treated transgenic mice. These results suggest that human CD36 overexpression is a risk factor of AKI and its progression to chronic kidney disease.

Adenovirus-mediated P311 ameliorates renal fibrosis through inhibition of epithelial-mesenchymal transition via TGF-β1-Smad-ILK pathway in unilateral ureteral obstruction rats

Epithelial-mesenchymal transition (EMT) is a critical step and key factor during renal fibrosis. Preventing renal tubular EMT is important for delaying the progression of chronic kidney disease (CKD). P311, a highly conserved 8-kDa intracellular protein, has been indicated as an important factor in myofibroblast transformation and in the progression of fibrosis. However, the related studies on P311 on renal fibrosis are limited and the mechanisms of P311 in the progression of renal tubulointerstitial fibrosis remain largely unknown. In the present study, we examined the effect of P311 on transforming growth factor-β1 (TGF-β1)-mediated EMT in a rat model of unilateral ureteral occlusion (UUO) renal fibrosis. The recombinant adenovirus p311 (also called Ad-P311) was constructed and transferred it into UUO rats, the preventive effect and possible mechanism of P311 on TGF-β1-mediated EMT were explored. The UUO model was established successfully and Ad-P311 was administered into UUO rats each week for 4 weeks, then the serum levels of Cr, blood urea nitrogen (BUN) and albumin (ALB) were evaluated. H&E staining and Masson staining were performed to observe the pathological changes of kidneys. Immunohistochemical staining and western blot analysis were used to examine the EMT markers [E-cadherin and α-smooth muscle actin (α-SMA)], and signal transducers (p-Smad2/3 and Smad7). Integrin linked kinase (ILK) as a keyintracellular mediator that controls TGF-β1-mediated-EMT was also assayed by western blot analysis. The results showed that P311 could alleviate renal tubular damage and interstitial fibrosis improving Cr, BUN and ALB serum levels in UUO kidneys. Furthermore, P311 attenuated TGF-β1-mediated EMT through Smad-ILK signaling pathway with an increase in α-SMA, pSmad2/3 and ILK expression, and a decrease in E-cadherin and Smad7 expression in UUO kidneys. In conclusion, P311 may be involved in the pathogenesis of renal fibrosis by blocking TGF-β1-mediated EMT via TGF-β1-Smad-ILK pathway in UUO kidneys. P311 may be a novel target for the control of renal fibrosis and the progression of CKD.

Epigenetics and pathogenesis of systemic sclerosis; the ins and outs

The pathogenesis of many diseases is influenced by environmental factors which can affect human genome and be inherited from generation to generation. Adverse environmental stimuli are recognized through the epigenetic regulatory complex, leading to gene expression alteration, which in turn culminates in disease outcomes. Three epigenetic regulatory mechanisms modulate the manifestation of a gene, namely DNA methylation, histone changes, and microRNAs. Both epigenetics and genetics have been implicated in the pathogenesis of systemic sclerosis (SSc) disease. Genetic inheritance rate of SSc is low and the concordance rate in both monozygotic (MZ) and dizygotic (DZ) twins is little, implying other possible pathways in SSc pathogenesis scenario. Here, we provide an extensive overview of the studies regarding different epigenetic events which may offer insights into the pathology of SSc. Furthermore, epigenetic-based interventions to treat SSc patients were discussed.

MicroRNAs associated with the development of kidney diseases in humans and animals

Mature microRNAs (miRNAs) are single-stranded RNAs with approximately 18-25 bases, and their sequences are highly conserved among animals. miRNAs act as posttranscriptional regulators by binding mRNAs, and their main function involves the degradation of their target mRNAs. Recent studies revealed altered expression of miRNAs in the kidneys during the progression of acute kidney injury (AKI) and chronic kidney disease (CKD) in humans and experimental rodent models by using high-throughput screening techniques including microarray and small RNA sequencing. Particularly, miR-21 seems to be strongly associated with renal pathogenesis both in the glomerulus and tubulointerstitium. Furthermore, abundant evidence has been gathered showing the involvement of miRNAs in renal fibrosis. Because of the complex morphofunctional organization of the mammalian kidneys, it is crucial both to determine the exact localization of the kidney cells that express the miRNAs, which has been addressed mainly using in situ hybridization methods, and to identify precisely which mRNAs are bound and degraded by these miRNAs, which has been studied mostly through in vitro analysis. To discover novel biomarker candidates, miRNA levels in urine supernatant, sediment, and exosomal fraction were comprehensively investigated in different types of kidney disease, including drug-induced AKI, ischemia-induced AKI, diabetic nephropathy, lupus nephritis, and IgA nephropathy. Recent studies also demonstrated the therapeutic effect of miRNA and/or anti-miRNA administrations. The intent of this review is to illustrate the state-of-the-art research in the field of miRNAs associated with renal pathogenesis, especially focusing on AKI and CKD in humans and animal models.

Telbivudine attenuates UUO-induced renal fibrosis via TGF-β/Smad and NF-κB signaling

Renal fibrosis yields decreased renal function and is a potent contributor to chronic kidney disease (CKD). Telbivudine (LdT) is an anti-hepatitis B virus (HBV) drug that has been found to steadily improve renal function, but the mechanism of drug action is unclear. One explanation is that LdT impacts inflammatory or fibrotic pathways. In this study, we investigated renal protection by LdT in a rat model of unilateral ureteral obstruction (UUO). UUO rats received oral gavage of LdT (1, 1.5, or 2g/kg/day) for 5weeks. Kidney tissues were examined histopathologically with hematoxylin and eosin and Masson's trichrome stain. To assess proliferation of myofibroblasts and matrix accumulation, α-smooth muscle actin (α-sma) and collagen type I and III were detected. Interleukin-1 (IL-1) and tumor necrosis factor (TNF)-α were evaluated as a measure of proinflammatory cytokines. Transforming growth factor (TGF)-β and nuclear factor-κB (NF-κB) were considered the canonical signaling components in our investigation of the underlying mechanism of LdT action. Histopathology results indicated that LdT ameliorates renal injury and matrix accumulation. Expression of α-sma and collagen I/III as well as key fibrotic signaling factors in the TGF-β/Smad pathway were downregulated. In addition, LdT suppressed the release of IL-1 and TNF-α and decreased the expression of NF-κB by inhibiting toll-like receptor 4. Taken together, these findings indicate that LdT can attenuate renal fibrosis and inflammation via TGF-β/Smad and NF-κB pathways in UUO.

Genome-wide Profiling of Urinary Extracellular Vesicle microRNAs Associated With Diabetic Nephropathy in Type 1 Diabetes

Introduction

Diabetic nephropathy (DN) is a form of progressive kidney disease that often leads to end-stage renal disease (ESRD). It is initiated by microvascular complications due to diabetes. Although microalbuminuria (MA) is the earliest clinical indication of DN among patients with type 1 diabetes (T1D), it lacks the sensitivity and specificity to detect the early onset of DN. Recently, microRNAs (miRNAs) have emerged as critical regulators in diabetes as well as various forms of kidney disease, including renal fibrosis, acute kidney injury, and progressive kidney disease. Additionally, circulating extracellular miRNAs, especially miRNAs packaged in extracellular vesicles (EVs), have garnered significant attention as potential noninvasive biomarkers for various diseases and health conditions.

Methods

As part of the University of Pittsburgh Epidemiology of Diabetes Complications (EDC) study, urine was collected from individuals with T1D with various grades of DN or MA (normal, overt, intermittent, and persistent) over a decade at prespecified intervals. We isolated EVs from urine and analyzed the small-RNA using NextGen sequencing.

Results

We identified a set of miRNAs that are enriched in urinary EVs compared with EV-depleted samples, and identified a number of miRNAs showing concentration changes associated with DN occurrence, MA status, and other variables, such as hemoglobin A1c levels.

Conclusion

Many of the miRNAs associated with DN occurrence or MA status directly target pathways associated with renal fibrosis (including transforming growth factor-β and phosphatase and tensin homolog), which is one of the major contributors to the pathology of DN. These miRNAs are potential biomarkers for DN and MA.

Antilipotoxicity Activity of Osmanthus fragrans and Chrysanthemum morifolium Flower Extracts in Hepatocytes and Renal Glomerular Mesangial Cells

The excess influx of free fatty acids (FFAs) into nonadipose tissues, such as those of liver and kidney, induces lipotoxicity leading to hepatic steatosis and renal dysfunction. The aim of this study was to investigate the protective effects of methanolic flower extracts of Osmanthus fragrans (OF) and Chrysanthemum morifolium (CM) against FFA-induced lipotoxicity in hepatocytes (human HepG2 cells) and renal glomerular mesangial cells (mouse SV40-Mes13 cells). The results showed that OF and CM significantly suppressed FFA-induced intracellular triacylglycerol accumulation via partially inhibiting the gene expression of sterol regulatory element-binding protein-1c (SREBP-1c) and glycerol-3-phosphate acyltransferase (GPAT) in HepG2 cells. Both extracts inhibited reactive oxygen species (ROS) generation by FFA-stimulated HepG2 cells. OF and CM also suppressed the mRNA expression of interleukin- (IL-) 1β, IL-6, IL-8, tumor necrosis factor- (TNF-) α, and transforming growth factor- (TGF-) β by HepG2 cells treated with conditioned medium derived from lipopolysaccharide-treated THP-1 monocytes. Furthermore, OF and CM effectively inhibited oleate-induced cellular lipid accumulation, TGF-β secretion, and overexpression of fibronectin in mesangial cells. In conclusion, OF and CM possess hepatoprotective activity by inhibiting hepatic fat load and inflammation and renal protection by preventing FFA-induced mesangial extracellular matrix formation.

LncRNA COL1A2-AS1 inhibits the scar fibroblasts proliferation via regulating miR-21/Smad7 pathway

lncRNA COL1A2-AS1 (COL1A2 antisense RNA 1), a lncRNA overexpressed in hypertrophic scar, has been demonstrated to be involved in the hypertrophic scar formation. However, the mechanisms of lncRNA COL1A2-AS1 inhibiting the scar fibroblasts proliferation remains not well understood. In this study, we demonstrated that lncRNA COL1A2-AS1 was upregulated in hypertrophic scar tissue and fibroblasts, and suppressed fibroblasts proliferation by promoting Smad7 expression. Furthermore, we found that miR-21 was involved in lncRNA COL1A2-AS1-induced expression of Smad7, by which COL1A2-AS1 acted as endogenous sponge to adsorb miR-21 and in turn regulated Smad7 and a cascade of molecular to play a protective role in hypertrophic scar. In addition, overexpression of miR-21 attenuated COL1A2-AS1-mediated proliferation suppression of hypertrophic scar fibroblasts. In conclusion, our study demonstrated that COL1A2-AS1/miR-21/Smad pathway plays an important role in inhibiting hypertrophic scar formation, and suggested this novel pathway may be a new target for hypertrophic scar treatment.

Urinary miRNAs as Biomarkers for Noninvasive Evaluation of Radiation-Induced Renal Tubular Injury

Radiation nephropathy is one of the common late effects in cancer survivors who received radiotherapy as well as in victims of radiation accidents. The clinical manifestations of radiation nephropathy occur months after exposure. To date, there are no known early biomarkers to predict the future development of radiation nephropathy. This study focuses on the development of urinary biomarkers providing readout of acute responses in renal tubular epithelial cells. An amplification-free hybridization-based nCounter assay was used to detect changes in mouse urinary miRNAs after irradiation. After a single LD₅₀ of total-body irradiation (TBI) or clinically relevant fractionated doses (2 Gy twice daily for 3 days), changes in urinary levels of microRNAs followed either an early pattern, peaking at 6-8 h postirradiation and gradually declining, or later pattern, peaking from 24 h to 7 days. Of 600 miRNAs compared, 12 urinary miRNAs showed the acute response and seven showed the late response, common to both irradiation protocols. miR-1224 and miR-21 were of particular interest, since they were the most robust acute and late responders, respectively. The early responding miR-1224 also exhibited good dose response after 2, 4, 6 and 8 Gy TBI, indicating its potential use as a biomarker for radiation exposure. In situ hybridization of irradiated mouse kidney sections and cultured mouse primary renal tubular cells confirmed the tubular origin of miR-1224. A significant upregulation in hsa-miR-1224-3p expression was also observed in human proximal renal tubular cells after irradiation. Consistent with mouse urine data, a similar expression pattern of hsa-miR-1224-3p and hsa-miR-21 were observed in urine samples collected from human leukemia patients preconditioned with TBI. This proof-of-concept study shows the potential translational utility of urinary miRNA biomarkers for radiation damage in renal tubules with possible prediction of late effects.

MicroRNA-542-3p inhibits oral squamous cell carcinoma progression by inhibiting ILK/TGF-β1/Smad2/3 signaling

In this study, we investigated the effects of microRNA-542-3p (miR-542-3p) on ILK/TGF-β1/Smad2/3 signaling and oral squamous cell carcinoma (OSCC) progression. Levels of miR-542-3p were lower in OSCC tissues (n=108) than adjacent normal tissues, whereas levels of ILK, TGF-β1 and Smad2/3 were higher. Patients with undifferentiated tumors, advanced TNM stage and lymph node metastasis showed low miR-542-3p levels. This was accompanied by high ILK expression and poor survival. Dual luciferase reporter assays of SCC-9 cells showed that miR-542-3p inhibited ILK gene expression by binding to its 3’UTR at 233-240 bp. SCC-9 cells transfected with miR-542-3p mimics exhibited elevated miR-542-3p and decreased ILK, TGF-β1 and Smad2/3 expression. They also showed reduced self-renewal (fewer CD44⁺ cells and tumor-spheres), invasiveness, migration, proliferation and survival. Conversely, miR-542-3p inhibitors promoted increased self-renewal (more CD44⁺ cells and tumor-spheres), invasiveness, migration, proliferation and survival. In xenograft experiments with nude mice, SCC-9 cells transfected with miR-542-3p mimics or siRNA-ILK yielded tumors with smaller volumes and weights than control tumors. These results demonstrate that miR-542-3p is a tumor suppressor that inhibits ILK/TGF-β1/Smad2/3 signaling, thereby inhibiting OSCC progression.

Tiron ameliorates oxidative stress and inflammation in titanium dioxide nanoparticles induced nephrotoxicity of male rats

Although the widespread use of titanium dioxide nanoparticles (TiO₂ NPs), few studies were conducted on its hazard influence on human health. Tiron a synthetic vitamin E analog was proven to be a mitochondrial targeting antioxidant. The current investigation was performed to assess the efficacy of tiron against TiO₂ NPs induced nephrotoxicity. Eighty adult male rats divided into four different groups were used: group I was the control, group II received TiO2 NPs (100mg\Kg BW), group III received TiO2 NPs plus tiron (470mg\kg BW), and group IV received tiron alone. Urea, creatinine and total protein concentrations were measured in serum to assess the renal function. Antioxidant status was estimated by determining the activities of glutathione peroxidase, superoxide dismutase, malondialdehyde (MDA) level and glutathione concentration in renal tissue. As well as Renal fibrosis was evaluated though measuring of transforming growth factor-β1 (TGFβ1) and matrix metalloproteinase 9 (MMP9) expression levels and histopathological examination. TiO₂ NPs treated rats showed marked elevation of renal indices, depletion of renal antioxidant enzymes with marked increase in MDA concentration as well as significant up-regulation in fibrotic biomarkers TGFβ1 and MMP9. Oral administration of tiron to TiO₂ NPs treated rats significantly attenuate the renal dysfunction through decreasing of renal indices, increasing of antioxidant enzymes activities, down-regulate the expression of fibrotic genes and improving the histopathological picture for renal tissue. In conclusion, tiron was proved to attenuate the nephrotoxicity induced by TiO₂ NPs through its radical scavenging and metal chelating potency.

miR-200b inhibits proliferation and metastasis of breast cancer by targeting fucosyltransferase IV and α1,3-fucosylated glycans

Aberrant protein fucosylation is associated with cancer malignancy. Fucosyltransferase IV (FUT4) is the key enzyme catalyzing the biosynthesis of α1,3-linkage fucosylated glycans carried by glycoproteins on the cell surface, such as the tumor-associated sugar antigen Lewis Y (LeY). An abnormal increase in the levels of FUT4 and LeY is observed in many cancers and correlated with cell proliferation and metastasis. Some microRNAs (miRNAs) are known to negatively regulate gene expression. FUT4 is an oncogenic glycogene, and thus it is important to identify the specific miRNA targeting FUT4. In current study, we first identified miR-200b as a specific miRNA that inhibited FUT4 expression. We found that miR-200b level was decreased, whereas that of FUT4 was increased in tissues and serum of breast cancer compared with that in the control by real-time PCR, western blotting and enzyme-linked immunosorbent assay. The alterations of miR-200b and FUT4 level were recovered after chemotherapy. The results also showed that miR-200b suppressed FUT4 expression and inhibited tumor growth and metastasis in MCF-7 and MDA-MB-231 breast cancer cells, as well as in the xenografted tumor tissues and metastatic lung tissues. miR-200b decreased the α1,3-fucosylation and LeY biosynthesis on epidermal growth factor receptor (EGFR), as well as inactivation of EGFR and downstream phosphoinositide-3 kinase/Akt signaling pathway. In conclusion, the study highlights that FUT4 could apply as a novel target for miR-200b that suppress the proliferation and metastasis of breast cancer cells by reducing α1,3-fucosylation and LeY biosynthesis of glycoproteins. miR-200b and FUT4 are potential diagnostic and therapeutic targets for breast cancer.

Factors Promoting Development of Fibrosis in Crohn's Disease

The concepts on the pathophysiology of intestinal fibrosis in Crohn’s disease (CD) have changed in recent years. Some years ago fibrosis was regarded to be a consequence of long-standing inflammation with subsequent destruction of the gut wall matrix followed by scar formation and collagen deposition. Fibrosis in CD patients appeared to be an irreversible process that could hardly be influenced. Therefore, the main target in CD therapy was to control inflammation to avoid fibrosis development. Many of these assumptions seem to be only partially true. Inflammation may be a necessary prerequisite for the initiation of fibrosis. However, when the pathophysiologic processes that lead to fibrosis in CD patients have been initiated fibrosis development may be independent of inflammation and may continue even when inflammation is under good medical control. Fibrosis in CD also may be reversible. After strictureplasty local collagen deposits decrease or even disappear. With new animal models for intestinal fibrosis on the horizon, we need to spend more efforts on understanding the factors influencing fibrosis in CD patients to finally find specific therapies. In this context, it will be as important to find markers and quantitative imaging tools to have reliable endpoints for clinical trials in fibrosing CD.

Inhibition of ERK1/2 Signaling Impairs the Promoting Effects of TGF-β1 on Hepatocellular Carcinoma Cell Invasion and Epithelial-Mesenchymal Transition

Transforming growth factor-β (TGF-β) and ERK signaling have been implicated in various human cancers including hepatocellular carcinoma, but the underlying mechanism remains largely unclear. In this study, we aimed to explore the role of ERK1/2 in the regulation of TGF-β’s promoting and suppressive activities in HCC cells. Our data showed that treatment with TGF-β1 enhanced invasion and epithelial–mesenchymal transition (EMT) in HCC HepG2 cells, accompanied with increased MMP9 production and activation of Smad2/3 and ERK1/2, but inhibited tumor cell proliferation. These effects were eliminated by treatment with SB431542, a TGF-β inhibitor. Afterward, treatment with the MEK1/2 inhibitor U0126 reduced the TGF-β1-induced invasion and vimentin and MMP9 secretion in HepG2 cells, without affecting the inhibitory effects of TGF-β1 on HepG2 cell proliferation. Moreover, inhibition of Smad2/3 expression attenuated TGF-β1-induced cell invasion, ERK1/2 phosphorylation, and MMP9 production in HepG2 cells. However, knockdown of Slug only reduced cell invasion but did not affect ERK1/2 activation and MMP9 secretion in HepG2 cells. These data indicate that TGF-β1 activates ERK1/2 in HepG2 cells through the Smad2/3 pathway but not the Slug pathway. In summary, our study demonstrates that inhibition of ERK1/2 signaling attenuates the promoting effects of TGF-β1 on the metastatic phenotypes of HCC cells without affecting its suppressive effects on HCC cell proliferation. Therefore, we suggest that ERK1/2 may be used as a molecular target for the treatment of TGF-β-responsive HCC.

Changes in miRNA in the lung and whole blood after whole thorax irradiation in rats

We used a rat model of whole thorax x-ray irradiation to profile the microRNA (miRNA) in lung and blood up to 4 weeks after radiation. MiRNA from normal and irradiated Wistar rat lungs and whole blood were analyzed by next-generation sequencing and the changes by radiation were identified by differential deRNA-seq 1, 2, 3 and 4 weeks after irradiation. The average total reads/library was 2,703,137 with a mean of 88% mapping to the rat genome. Detailed profiles of 100 of the most abundant miRNA in rat blood and lung are described. We identified upregulation of 4 miRNA, miR-144-5p, miR-144-3p, miR-142-5p and miR-19a-3p in rat blood 2 weeks after radiation that have not previously been shown to be altered after radiation to the lung. Ingenuity Pathway Analysis identified signaling of inflammatory response pathways. These findings will support development of early detection methods, as well as mechanism(s) of injury and mitigation in patients after radiotherapy or radiological accidents.

MnTE-2-PyP Treatment, or NOX4 Inhibition, Protects against Radiation-Induced Damage in Mouse Primary Prostate Fibroblasts by Inhibiting the TGF-Beta 1 Signaling Pathway

Prostate cancer patients who undergo radiotherapy frequently suffer from side effects caused by radiation-induced damage to normal tissues adjacent to the tumor. Exposure of these normal cells during radiation treatment can result in tissue fibrosis and cellular senescence, which ultimately leads to postirradiation-related chronic complications including urinary urgency and frequency, erectile dysfunction, urethral stricture and incontinence. Radiation-induced reactive oxygen species (ROS) have been reported as the most potent causative factor for radiation damage to normal tissue. While MnTE-2-PyP, a ROS scavenger, protects normal cells from radiation-induced damage, it does not protect cancer cells during radiation treatment. However, the mechanism by which MnTE-2-PyP provides protection from radiation-induced fibrosis has been unclear. Our current study reveals the underlying molecular mechanism of radiation protection by MnTE-2-PyP in normal mouse prostate fibroblast cells. To investigate the role of MnTE-2-PyP in normal tissue protection after irradiation, primary prostate fibroblasts from C57BL/6 mice were cultured in the presence or absence of MnTE-2-PyP and exposed to 2 Gy of X rays. We found that MnTE-2-PyP could protect primary prostate fibroblasts from radiation-induced activation, as measured by the contraction of collagen discs, and senescence, detected by beta-galactosidase staining. We observed that MnTE-2-PyP inhibited the TGF-β-mediated fibroblast activation pathway by downregulating the expression of TGF-β receptor 2, which in turn reduced the activation and/or expression of SMAD2, SMAD3 and SMAD4. As a result, SMAD2/3-mediated transcription of profibrotic markers was reduced by MnTE-2-PyP. Due to the inhibition of the TGF-β pathway, fibroblasts treated with MnTE-2-PyP could resist radiation-induced activation and senescence. NADPH oxidase 4 (NOX4) expression is upregulated after irradiation and produces ROS. As was observed with MnTE-2-PyP treatment, NOX4^-/- fibroblasts were protected from radiation-induced fibroblast activation and senescence. However, NOX4^-/- fibroblasts had reduced levels of active TGF-β1, which resulted in decreased TGF-β signaling. Therefore, our data suggest that reduction of ROS levels, either by MnTE-2-PyP treatment or by eliminating NOX4 activity, significantly protects normal prostate tissues from radiation-induced tissue damage, but that these approaches work on different components of the TGF-β signaling pathway. This study proposes a crucial insight into the molecular mechanism executed by MnTE-2-PyP when utilized as a radioprotector. An understanding of how this molecule works as a radioprotector will lead to a better controlled mode of treatment for post therapy complications in prostate cancer patients.