Signaling mechanism of TGF-beta1 in prevention of renal inflammation: role of Smad7

Trabecular meshwork cells are a valuable resource for cellular therapy of glaucoma

Trabecular meshwork (TM) contains a subset of adult stem cells or progenitors that can be differentiated into corneal endothelial cells, adipocytes and chondrocytes, but not osteocytes or keratocytes. Accordingly, these progenitors can be utilized as a cell‐based therapy to prevent blindness caused by glaucoma, corneal endothelial dysfunction and other diseases in general. In this review, we review in vitro expansion techniques for TM progenitors, discuss their phenotypic properties, and highlight their potential clinical applications in various ophthalmic diseases.

Fate alteration of bone marrow-derived macrophages ameliorates kidney fibrosis in murine model of unilateral ureteral obstruction

Background

Renal fibrosis is a key pathological feature and final common pathway leading to end-stage kidney failure in many chronic kidney diseases. Myofibroblast is the master player in renal fibrosis. However, myofibroblasts are heterogeneous. Recent studies show that bone marrow-derived macrophages transform into myofibroblasts by transforming growth factor (TGF)-β-induced macrophage–myofibroblast transition (MMT) in renal fibrosis.

Methods

TGF-β signaling was redirected by inhibition of β-catenin/T-cell factor (TCF) to increase β-catenin/Foxo in bone marrow-derived macrophages. A kidney fibrosis model of unilateral ureteral obstruction was performed in EGFP bone marrow chimera mouse. MMT was examined by flow cytometry analysis of GFP+F4/80+α-SMA+ cells from unilateral ureteral obstruction (UUO) kidney, and by immunofluorescent staining of bone marrow-derived macrophages in vitro. Inflammatory and anti-inflammatory cytokines were analysis by enzyme-linked immunosorbent assay.

Results

Inhibition of β-catenin/TCF by ICG-001 combined with TGF-β1 treatment increased β-catenin/Foxo1, reduced the MMT and inflammatory cytokine production by bone marrow-derived macrophages, and thereby, reduced kidney fibrosis in the UUO model.

Conclusions

Our results demonstrate that diversion of β-catenin from TCF to Foxo1-mediated transcription not only inhibits the β-catenin/TCF-mediated fibrotic effect of TGF-β, but also enhances its anti-inflammatory action, allowing therapeutic use of TGF-β to reduce both inflammation and fibrosis at least partially by changing the fate of bone marrow-derived macrophages.

Loss of Smad7 Promotes Inflammation in Rheumatoid Arthritis

Objective: Smad7 is an inhibitory Smad and plays a protective role in many inflammatory diseases. However, the roles of Smad7 in rheumatoid arthritis (RA) remain unexplored, which were investigated in this study.

Methods: The activation of TGF-β/Smad signaling was examined in synovial tissues of patients with RA. The functional roles and mechanisms of Smad7 in RA were determined in a mouse model of collagen-induced arthritis (CIA) in Smad7 wild-type (WT) and knockout (KO) CD-1 mice, a strain resistant to autoimmune arthritis induction.

Results: TGF-β/Smad3 signaling was markedly activated in synovial tissues of patients with RA, which was associated with the loss of Smad7, and enhanced Th17 and Th1 immune response. The potential roles of Smad7 in RA were further investigated in a mouse model of CIA in Smad7 WT/KO CD-1 mice. As expected, Smad7-WT CD-1 mice did not develop CIA. Surprisingly, CD-1 mice with Smad7 deficiency developed severe arthritis including severe joint swelling, synovial hyperplasia, cartilage damage, massive infiltration of CD3⁺ T cells and F4/80⁺ macrophages, and upregulation of proinflammatory cytokines IL-1β, TNFα, and MCP-1. Further studies revealed that enhanced arthritis in Smad7 KO CD-1 mice was associated with increased Th1, Th2 and, importantly, Th17 over the Treg immune response with overactive TGF-β/Smad3 and proinflammatory IL-6 signaling in the joint tissues.

Conclusions: Smad7 deficiency increases the susceptibility to autoimmune arthritis in CD-1 mice. Enhanced TGF-β/Smad3-IL-6 signaling and Th17 immune response may be a mechanism through which disrupted Smad7 causes autoimmune arthritis in CD-1 mice.

Inflammatory Role of Cancer-Associated Fibroblasts in Invasive Breast Tumors Revealed Using a Fibrous Polymer Scaffold

Inflammation in cancer fuels metastasis and worsens prognosis. Cancer-associated fibroblasts (CAFs) present in the tumor stroma play a vital role in mediating the cascade of cancer inflammation that drives metastasis by enhancing angiogenesis, tissue remodeling, and invasion. In vitro models that faithfully recapitulate CAF-mediated inflammation independent of coculturing with cancer cells are nonexistent. We have engineered fibrous matrices of poly(ε-caprolactone) (PCL) that can maintain the manifold tumor-promoting properties of patient-derived CAFs, which would otherwise require repetitive isolation and complex coculturing with cancer cells. On these fibrous matrices, CAFs proliferated and remodeled the extracellular matrix (ECM) in a parallel-patterned manner mimicking the ECM of high-grade breast tumors and induced stemness in breast cancer cells. The response of the fibroblasts was observed to be sensitive to the scaffold architecture and not the polymer composition. The CAFs cultured on fibrous matrices exhibited increased activation of the NF-κB pathway and downstream proinflammatory gene expression compared to CAFs cultured on conventional two-dimensional (2D) dishes and secreted higher levels of proinflammatory cytokines such as IL-6, GM-CSF, and MIP-3α. Consistent with this, we observed increased infiltration of inflammatory cells to the tumor site and enhanced invasiveness of the tumor in vivo when tumor cells were injected admixed with CAFs grown on fibrous matrices. These data suggest that CAFs better retain their tumor-promoting proinflammatory properties on fibrous polymeric matrices, which could serve as a unique model to investigate the mechanisms of stroma-induced inflammation in cancer progression.

Inflammatory reaction, clinical efficacy, and safety of bacterial cellulose wound dressing containing silk sericin and polyhexamethylene biguanide for wound treatment

Bacterial cellulose wound dressings containing silk sericin and PHMB (BCSP) were developed in our previous studies. It had good physical properties, efficacy, and safety. For further use as a medical material, this dressing was investigated for its efficacy and safety in split-thickness skin graft (STSG) donor-site wound treatment compared to Bactigras® (control). Moreover, the inflammatory responses to both dressings were also deeply investigated. For in vivo study, expressions of anti-inflammatory cytokines were intensely considered in the tissue interfacing area. The result showed that IL-4 and TGF-β from BCSP-treated tissue had advantages over Bactigras®-treated tissue at 14 and 21 days post-implantation. For clinical study, a single-blinded, randomized controlled study was generated. The half of STSG donor site wound was randomly assigned to cover with BCSP or Bactigras®. Twenty-one patients with 32 STSG donor site wounds were enrolled. The results showed that wound-healing time was not significantly different in both dressings. However, wound quality of BCSP was better than Bactigras® at healing time and after 1 month (p < 0.05). The pain scores of BCSP-treated wound were statistically significant lower than Bactigras®-treated wound (p < 0.05). No sign of infection or adverse event was observed after treatment with both dressings. In conclusion, the inflammation responses of the dressing were clearly clarified. The advantages of BCSP were wound-quality improvement, pain reduction, and infection protection without adverse events. It was fit to be used as the alternative treatment of STSG donor site wound.

IL‑1β and TNF‑α suppress TGF‑β‑promoted NGF expression in periodontal ligament‑derived fibroblasts through inactivation of TGF‑β‑induced Smad2/3‑ and p38 MAPK‑mediated signals

Mechanosensitive (MS) neurons in the periodontal ligament (PDL) pass information to the trigeminal ganglion when excited by mechanical stimulation of the tooth. During occlusal tooth trauma of PDL tissues, MS neurons are injured, resulting in atrophic neurites and eventual degeneration of MS neurons. Nerve growth factor (NGF), a neurotrophic factor, serves important roles in the regeneration of injured sensory neurons. In the present study, the effect of pro‑inflammatory cytokines, including interleukin 1β (IL‑1β) and tumor necrosis factor α (TNF‑α), on transforming growth factor β1 (TGF‑β1)‑induced NGF expression was evaluated in rat PDL‑derived SCDC2 cells. It was observed that TGF‑β1 promoted NGF expression via Smad2/3 and p38 mitogen‑activated protein kinase (MAPK) activation. IL‑1β and TNF‑α suppressed the TGF‑β1‑induced activation of Smad2/3 and p38 MAPK, resulting in the abrogation of NGF expression. NGF secreted by TGF‑β1‑treated SCDC2 cells promoted neurite extension and the expression of tyrosine hydroxylase, a rate‑limiting enzyme in dopamine synthesis in rat pheochromocytoma PC12 cells. These results suggested that pro‑inflammatory cytokines suppressed the TGF‑β‑mediated expression of NGF in PDL‑derived fibroblasts through the inactivation of TGF‑β‑induced Smad2/3 and p38 MAPK signaling, possibly resulting in the disturbance of the regeneration of injured PDL neurons.

Novel Interplay Between Smad1 and Smad3 Phosphorylation via AGE Regulates the Progression of Diabetic Nephropathy

Diabetic nephropathy (DN) is the major cause of end-stage renal failure and is associated with increased morbidity and mortality compared with other causes of renal diseases. We previously found that Smad1 plays a critical role in the development of DN both in vitro and in vivo. However, functional interaction between Smad1 and Smad3 signaling in DN is unclear. Here, we addressed the molecular interplay between Smad1 and Smad3 signaling under a diabetic condition by using Smad3-knockout diabetic mice. Extracellular matrix (ECM) protein overexpression and Smad1 activation were observed in the glomeruli of db/db mice but were suppressed in the glomeruli of Smad3^+/-; db/db mice. Smad3 activation enhanced the phosphorylation of Smad1 C-terminal domain but decreased the phosphorylation of linker domain, thus regulating Smad1 activation in advanced glycation end product-treated mesangial cells (MCs). However, forced phosphorylation of the Smad1 linker domain did not affect Smad3 activation in MCs. Phosphorylation of the Smad1 linker domain increased in Smad3^+/-; db/db mice and probucol-treated db/db mice, which was consistent with the attenuation of ECM overproduction. These results indicate that Smad3 expression and activation or probucol treatment alters Smad1 phosphorylation, thus suggesting new molecular mechanisms underlying DN development and progression.

Transforming growth factor-β signalling in renal fibrosis: from Smads to non-coding RNAs

Transforming growth factor-β (TGF-β) is the key player in tissue fibrosis. However, antifibrotic therapy targeting this multifunctional protein may interfere with other physiological processes to cause side effects. Thus, precise therapeutic targets need to be identified by further understanding the underlying mechanisms of TGF-β1 signalling during fibrogenesis. Equilibrium of Smad signalling is crucial for TGF-β-mediated renal fibrosis, where Smad3 is pathogenic but Smad2 and Smad7 are protective. The activation of TGF-β1/Smad signalling triggers extracellular matrix deposition, and local myofibroblast generation and activation. Mechanistic studies have shown that TGF-β/Smad3 transits the microRNA profile from antifibrotic to profibrotic and therefore promotes renal fibrosis via regulating non-coding RNAs at transcriptional levels. More importantly, disease-specific Smad3-dependent long non-coding RNAs have been recently uncovered from mouse kidney disease models and may represent novel precision therapeutic targets for chronic kidney disease. In this review, mechanisms of TGF-β-driven renal fibrosis via non-coding RNAs and their translational capacities will be discussed in detail.

IL‑1β and TNF‑α suppress TGF‑β‑promoted NGF expression in periodontal ligament‑derived fibroblasts through inactivation of TGF‑β‑induced Smad2/3‑ and p38 MAPK‑mediated signals

Mechanosensitive (MS) neurons in the periodontal ligament (PDL) pass information to the trigeminal ganglion when excited by mechanical stimulation of the tooth. During occlusal tooth trauma of PDL tissues, MS neurons are injured, resulting in atrophic neurites and eventual degeneration of MS neurons. Nerve growth factor (NGF), a neurotrophic factor, serves important roles in the regeneration of injured sensory neurons. In the present study, the effect of pro‑inflammatory cytokines, including interleukin 1β (IL‑1β) and tumor necrosis factor α (TNF‑α), on transforming growth factor β1 (TGF‑β1)‑induced NGF expression was evaluated in rat PDL‑derived SCDC2 cells. It was observed that TGF‑β1 promoted NGF expression via Smad2/3 and p38 mitogen‑activated protein kinase (MAPK) activation. IL‑1β and TNF‑α suppressed the TGF‑β1‑induced activation of Smad2/3 and p38 MAPK, resulting in the abrogation of NGF expression. NGF secreted by TGF‑β1‑treated SCDC2 cells promoted neurite extension and the expression of tyrosine hydroxylase, a rate‑limiting enzyme in dopamine synthesis in rat pheochromocytoma PC12 cells. These results suggested that pro‑inflammatory cytokines suppressed the TGF‑β‑mediated expression of NGF in PDL‑derived fibroblasts through the inactivation of TGF‑β‑induced Smad2/3 and p38 MAPK signaling, possibly resulting in the disturbance of the regeneration of injured PDL neurons.

Tumor-fibroblast interactions stimulate tumor vascularization by enhancing cytokine-driven production of MMP9 by tumor cells

Advance-stage breast carcinomas include significant amounts of fibroblasts and infiltrating immune cells which have been implicated in tumor growth, recurrence, and response to therapy. The present study investigated the contribution of fibroblasts to tumor growth using direct tumor-fibroblast co-cultures and tumor xenograft models. Our findings revealed that fibroblasts enhance breast carcinoma growth by promoting the tumor vasculature via the MMP9-dependent mechanism. In tumor-fibroblast co-cultures, fibroblasts increased expression of TGF-β, TNF, and IL-1β cytokines in tumor cells. These cytokines cooperatively induced expression of matrix metalloproteinase MMP9 in tumor cells. Knockdown of MMP9 by shRNA significantly reduced tumor vascularization induced by fibroblasts. Mechanistically, our findings argue that expression of MMP9 in tumor cellsis regulated by crosstalk of TGF-β with TNF and/or IL-1β cytokines. The mechanism of this cooperative response did not involve cross-activation of the canonical signaling pathways as TGF-β did not activate RELA/p65 signaling, while TNF did not affect SMAD signaling. Instead, TGF-β and TNF cytokines co-stimulated MAP kinases and expression of JUN and JUNB, AP1 transcription factor subunits, which together with RELA/p65 were essential for the regulation of MMP9. Depletion of JUN and JUNB or RELA in tumor cells blocked the cooperative induction of MMP9 by the cytokines. Thus, our studies uncovered a previously unappreciated role of tumor-fibroblast interactions in the stimulation of tumor angiogenesis, and an essential role of the MAPK-AP1 axis in the cooperative up-regulation of the angiogenic driver MMP9 by cytokine crosstalk.

Specific Inhibitor of Smad3 (SIS3) Attenuates Fibrosis, Apoptosis, and Inflammation in Unilateral Ureteral Obstruction Kidneys by Inhibition of Transforming Growth Factor β (TGF-β)/Smad3 Signaling

Background

Fibrosis is the common pathological feature in most kinds of chronic kidney disease (CKD). TGF-β/Smads signaling is the master pathway regulating kidney fibrosis pathogenesis, in which Smad3 acts as the integrator of various pro-fibrosis signals. In this study, we analyzed the role of SIS3, a specific inhibitor of Smad3, in mouse unilateral ureteral obstruction (UUO) kidneys.

Material/Methods

UUO mice were intraperitoneally injected with 0.2 mg/kg/day or 2 mg/kg/day of SIS3 or control saline for 7 days, followed by analysis of structure injury, fibrosis status, inflammation, apoptosis, and TGF-β/Smads signaling activity.

Results

Our results indicated that SIS3 treatment dosage-dependently relieved the gross structure injury and tubular necrosis in UUO kidneys. Masson staining, immunohistochemistry, and real-time PCR showed significantly decreased extracellular matrix deposition, fibronectin staining intensity, and RNA levels of collagen I and collagen III in SIS3-treated UUO kidneys. SIS3 treatment also suppressed the activation of myofibroblasts, as evidenced by decreased expression levels of α-SMA and vimentin in UUO kidneys. The TGF-β/Smads signaling activity analysis showed that SIS3 inhibited the phosphorylation of Smad3 but not Smad2 and decreased the protein level of TGF-β1, suggesting specific inhibition of the TGF-β/Smad3 pathway in UUO kidneys. Furthermore, SIS3 treatment also ameliorated the increased pro-inflammatory TNF-α and COX2 in UUO kidneys and circulating IL-1β in UUO mice, and inhibited caspase-3 activity and the number of apoptotic cells.

Conclusions

SIS3 ameliorated fibrosis, apoptosis, and inflammation through inhibition of TGF-β/Smad3 signaling in UUO mouse kidneys.

Influence of amygdalin on PDG, IGF and PDGFR expression in HSC-T6 cells

The aim of the present study was to elucidate the mechanism of amygdalin treatment on reducing liver fibrosis by investigating its role in regulating the expression level of platelet-derived growth factor (PDGF), insulin-like growth factor (IGF) and PDGF receptor (PDGFR) in the hepatic stellate cell (HSC)-T6 line. HSC-T6 cells were used as an in vitro model and randomly assigned into four groups: control, high-dose amygdalin, mid-dose amygdalin and low-dose amygdalin. Following amygdalin treatment, compared with the control, a high dose of amygdalin significantly suppressed the mRNA expression of PDGF and IGF (each P<0.05), whereas moderate and low doses showed no significant effect, relatively low doses of amygdalin are not sufficient to transfer signals to its receptor. The high-dose amygdalin and low-dose amygdalin displayed suppressed protein expression of PDGF at 24, 48 and 72 h, with the high-dose group exhibiting the most marked suppression at all three time points. By reducing the transcription of PDGF and IGF mRNA and the expression of PDGF protein, amygdalin decreased the synthesis and release of PDGF and IGF, thereby reducing the influence of PDGF and IGF on HSCs, thus protecting the liver from fibrosis.

Sitagliptin ameliorates diabetic nephropathy by blocking TGF-β1/Smad signaling pathway

Diabetic nephropathy (DN) is the leading cause of end-stage failure of the kidney, but the efficacy of current strategies available for the prevention of DN remains unsatisfactory. The purpose of this study was to assess whether sitagliptin (SIT) has therapeutic potential for prevention of DN and to investigate its possible mechanism. The effects of SIT on DN were investigated in rats with type 2 diabetes mellitus (T2DM) and rat mesangial cells (MCs) induced by high glucose. T2DM rats were administered at a dose of 10 mg/kg SIT. The kidney index, 24 h urinary protein, blood urea nitrogen (BUN), serum creatinine (Cr), accumulation of glycogen and collagens were investigated by different methods. MCs were administered with SIT at doses of 0.1, 1 and 10 µmol/ml. The possible mechanism of SIT on protection of diabetic kidney injury was examined by expression of transforming growth factor-β1 (TGF-β1)/Smad pathway. The results showed that the SIT-treated diabetic rats significantly reduced diabetic kidney injury by inhibiting the kidney index and attenuating 24 h urinary protein, reducing BUN and serum creatinine, inhibiting progressive renal fibrosis and increassing extracellular matrix including collagen IV and fibronectin. Further studies showed that inhibition of renal fibrosis in SIT-treated diabetic rats and MCs were associated with rebalancing of TGF-β1/Smad pathway. Sitagliptin may be a potent agent for preventing the progression of DN through inhabiting TGF-β1/Smad-mediated renal fibrosis.

Redirecting TGF-β Signaling through the β-Catenin/Foxo Complex Prevents Kidney Fibrosis

TGF-β is a key profibrotic factor, but targeting TGF-β to prevent fibrosis also abolishes its protective anti-inflammatory effects. Here, we investigated the hypothesis that we can redirect TGF-β signaling by preventing downstream profibrotic interaction of β-catenin with T cell factor (TCF), thereby enhancing the interaction of β-catenin with Foxo, a transcription factor that controls differentiation of TGF-β induced regulatory T cells (iTregs), and thus, enhance anti-inflammatory effects of TGF-β In iTregs derived from EL4 T cells treated with recombinant human TGF-β1 (rhTGF-β1) in vitro, inhibition of β-catenin/TCF transcription with ICG-001 increased Foxp3 expression, interaction of β-catenin and Foxo1, binding of Foxo1 to the Foxp3 promoter, and Foxo transcriptional activity. Moreover, the level of β-catenin expression positively correlated with the level of Foxo1 binding to the Foxp3 promoter and Foxo transcriptional activity. T cell fate mapping in Foxp3^gfp Ly5.1/5.2 mice revealed that coadministration of rhTGF-β1 and ICG-001 further enhanced the expansion of iTregs and natural Tregs observed with rhTGF-β1 treatment alone. Coadministration of rhTGF-β1 with ICG-001 also increased the number of Tregs and reduced inflammation and fibrosis in the kidney fibrosis models of unilateral ureteric obstruction and ischemia-reperfusion injury. Notably, ICG-001 prevented the fibrosis in distant organs (lung and liver) caused by rhTGF-β1. Together, our results show that diversion of β-catenin from TCF- to Foxo-mediated transcription inhibits the β-catenin/TCF-mediated profibrotic effects of TGF-β while enhancing the β-catenin/Foxo-mediated anti-inflammatory effects. Targeting β-catenin/Foxo may be a novel therapeutic strategy in the treatment of fibrotic diseases that lead to organ failure.

Therapeutic potential of microRNAs for the treatment of renal fibrosis and CKD

Chronic kidney disease (CKD), defined as reduced glomerular filtration rate, is increasingly becoming a major public health issue. At the histological level, renal fibrosis is the final common pathway leading to end-stage renal disease, irrespective of the initial injury. According to this view, antifibrotic agents should slow or halt the progression of CKD. However, due to multiple overlapping pathways stimulating fibrosis, it has been difficult to develop antifibrotic drugs that delay or reverse the progression of CKD. MicroRNAs (miRNAs) are small noncoding RNA molecules, 18-22 nucleotides in length, that control many developmental and cellular processes as posttranscriptional regulators of gene expression. Emerging evidence suggests that miRNAs targeted against genes involved in renal fibrosis might be potential candidates for the development of antifibrotic therapies for CKD. This review will discuss some of the miRNAs, such as Let-7, miR-21,-29, -192, -200,-324, -132, -212, -30, -126, -433, -214, and -199a, that are implicated in renal fibrosis and the potential to exploit these molecular targets for the treatment of CKD.

Smad7 alleviates glomerular mesangial cell proliferation via the ROS-NF-κB pathway

OBJECTIVE

The aim of this study was to demonstrate that altered gene expression of Smad7regulated NF-κB expression and ROS production on Ang II (Angiotensin II)-induced rat glomerular mesangial cell (GMC) proliferation.

METHODS

pAdTrack-CMV-Smad7 was transduced into rat GMC by adeno-transduction using an ADV (adenovirus)-mediated vector in vivo. Diphenylene iodonium chloride (DPI) pre-treated GMC, and blocked ROS generation as determined by DCFH-DA method. Altered expressions of IκBα and p65 were monitored by Western blot analysis and immunofluorescence. GMC proliferation was tested by the Cell Counting Kit-8 assay. Apoptosis of GMC was detected by flow cytometric analysis.

RESULTS

Over-expression of Smad7 dampened the ability of Ang II to promote ROS synthesis and inhibited the ability of Ang II to decrease functional expression of IκBα. Moreover, Smad7 increased nuclear IκBα expression. Smad7 did not significantly influence the capacity of Ang II to increase protein expression of NF-κB p65. However, immunofluorescence analysis showed that Smad7 reduced nuclear NF-κB p65 level. Further, over-expression of Smad7 promoted GMC apoptosis by inhibiting NF-κB activation, which alleviated the Ang II-promoted proliferation of GMC.

CONCLUSIONS

Smad7 influenced NF-κB expression by regulating ROS generation, and induced GMC apoptosis to counter the Ang II-promoted proliferation.

Copper/zinc-loaded montmorillonite influences intestinal integrity, the expression of genes associated with inflammation, TLR4-MyD88 and TGF-β1 signaling pathways in weaned pigs after LPS challenge

This study was aimed at investigating whether dietary copper/zinc-loaded montmorillonite (Cu/Zn-Mt) could alleviate Escherichia coli LPS-induced intestinal injury through pro- and anti-inflammatory signaling pathways (TLRs, NLRs and TGF-β1) in weaned piglets. Eighteen 21-d-old pigs were randomly divided into three groups (control, LPS and LPS + Cu/Zn-Mt). After 21 d of feeding, pigs in the LPS group and LPS + Cu/Zn-Mt group received i.p. administration of LPS, whereas pigs in the control group received saline. At 4 h post-injection, jejunum samples were collected for analysis. The results indicated that, compared with the LPS group, supplemental Cu/Zn-Mt increased transepithelial electrical resistance, the expressions of anti-inflammatory cytokines (TGF-β1) in mRNA and protein levels, and decreased FD4 and the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-8 and IL-1β). The pro-inflammatory signaling pathways results demonstrated that Cu/Zn-Mt supplementation decreased the mRNA levels of TLR4 and its downstream signals (MyD88, IRAK1, TRAF6) but had no effect on NOD1 and NOD2 signals. Cu/Zn-Mt supplementation did not affect NF-κB p65 mRNA abundance, but down-regulated its protein expression. The anti-inflammatory signaling pathways results showed supplemental Cu/Zn-Mt also increased TβRII, Smad4 and Smad7 mRNA expressions. These findings suggested dietary Cu/Zn-Mt attenuated LPS-induced intestinal injury by alleviating intestinal inflammation, influencing TLR4-MyD88 and TGF-β1 signaling pathways in weaned pig.

Gender Differences in the Acute Kidney Injury to Chronic Kidney Disease Transition

This study evaluated if there is a sexual dimorphism in the acute kidney injury (AKI) to chronic kidney disease (CKD) transition and the time-course of the potential mechanisms involved in the dimorphic response. Female and male rats were divided into sham-operated or underwent 45-min renal ischemia (F + IR, and M + IR). All groups were studied at 24-h and 1, 2, 3, or 4-months post-ischemia. Additionally, oophorectomized rats were divided into sham or IR groups. After 24-h, AKI extent was simllar in females and males, but female rats exhibited less oxidative stress and increased renal GSH content. After 4-months and despite similar AKI, the M + IR group developed CKD characterized by proteinuria, tubulointerstitial fibrosis, glomerular hypertrophy, increased oxidative stress and a reduction in HIF1α and VEGF from the 1^st-month and persisting throughout the time-course studied. Interestingly, the F + IR group did not develop CKD due to lesser oxidative stress and increased eNOS, TGFβ and HIF1α mRNA levels from the 1^st-month after IR. Whereas, oophorectomized rats did develop CKD. We found a sexual dimorphic response in the AKI to CKD transition. Early antioxidant defense and higher TGFβ, HIF1α and eNOS were among the renoprotective mechanisms that the F + IR group demonstrated.

Periostin-binding DNA aptamer treatment attenuates renal fibrosis under diabetic conditions

Diabetic nephropathy, the major cause of chronic kidney disease, is associated with progressive renal fibrosis. Recently, accumulation of periostin, an extracellular matrix protein, was shown to augment renal fibrosis. Aptamers have higher binding affinities without developing the common side effects of antibodies. Thus, we evaluated the effect of periostin inhibition by an aptamer-based inhibitor on renal fibrosis under diabetic conditions. In vitro, transforming growth factor-β1 (TGF-β1) treatment significantly upregulated periostin, fibronectin, and type I collagen mRNA and protein expressions in inner medullary collecting duct (IMCD) cells. These increases were attenuated significantly in periostin-binding DNA aptamer (PA)-treated IMCD cells exposed to TGF-β1. In vivo, PA treatment attenuated the increased blood urea nitrogen levels in the diabetic mice significantly. Fibronectin and type I collagen mRNA and protein expressions increased significantly in the kidneys of diabetic mice: PA administration abrogated these increases significantly. Immunohistochemistry and Sirius Red staining also revealed that fibronectin expression was significantly higher and tubulointersititial fibrosis was significantly worse in diabetic mice kidneys compared with control mice. These changes were ameliorated by PA treatment. These findings suggested that inhibition of periostin using a DNA aptamer could be a potential therapeutic strategy against renal fibrosis in diabetic nephropathy.

Arctigenin suppresses renal interstitial fibrosis in a rat model of obstructive nephropathy

BACKGROUND

Renal tubulointerstitial fibrosis (TIF) is commonly the final result of a variety of progressive injuries and leads to end-stage renal disease. There are few therapeutic agents currently available for retarding the development of renal TIF.

PURPOSE

The aim of the present study is to evaluate the role of arctigenin (ATG), a lignan component derived from dried burdock (Arctium lappa L.) fruits, in protecting the kidney against injury by unilateral ureteral obstruction (UUO) in rats.

METHODS

Rats were subjected to UUO and then administered with vehicle, ATG (1 and 3mg/kg/d), or losartan (20mg/kg/d) for 11 consecutive days. The renoprotective effects of ATG were evaluated by histological examination and multiple biochemical assays.

RESULTS

Our results suggest that ATG significantly protected the kidney from injury by reducing tubular dilatation, epithelial atrophy, collagen deposition, and tubulointerstitial compartment expansion. ATG administration dramatically decreased macrophage (CD68-positive cell) infiltration. Meanwhile, ATG down-regulated the mRNA levels of pro-inflammatory chemokine monocyte chemoattractant protein-1 (MCP-1) and cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interferon-γ (IFN-γ), in the obstructed kidneys. This was associated with decreased activation of nuclear factor κB (NF-κB). ATG attenuated UUO-induced oxidative stress by increasing the activity of renal manganese superoxide dismutase (SOD2), leading to reduced levels of lipid peroxidation. Furthermore, ATG inhibited the epithelial-mesenchymal transition (EMT) of renal tubules by reducing the abundance of transforming growth factor-β1 (TGF-β1) and its type I receptor, suppressing Smad2/3 phosphorylation and nuclear translocation, and up-regulating Smad7 expression. Notably, the efficacy of ATG in renal protection was comparable or even superior to losartan.

CONCLUSION

ATG could protect the kidney from UUO-induced injury and fibrogenesis by suppressing inflammation, oxidative stress, and tubular EMT, thus supporting the potential role of ATG in renal fibrosis treatment.

Attenuation of renal damage in type I diabetic rats by umbelliferone - a coumarin derivative

BACKGROUND

It is well known that diabetes is one of the non-communicable disease affecting a large population worldwide. When diabetes remains untreated or uncontrolled, it leads to further serious complications, affecting vital organs like eyes, kidney, heart, etc. The present study was designed to evaluate effects of umbelliferone, a phytochemical, in treatment of diabetic nephropathy.

METHODS

Experimental model used was streptozotocin (55mg/kg, ip) induced diabetic nephropathy in male Sprague Dawley rats. After 28days of streptozotocin administration, diabetic animals were treated with umbelliferone at two dose levels, 20 and 40mg/kg for next 28days.

RESULTS

The results of the study showed that umbelliferone treatment significantly decreased the elevated plasma creatinine and blood urea nitrogen level while significantly increased the total protein and albumin level in diabetic animals. Creatinine clearance was improved in umbelliferone treated animals. Renal oxidative stress was decreased in umbelliferone treated animals significantly. Histopathological study of the kidney was carried out by specific stains like Hematoxylin-Eosin, Periodic Acid Schiff and Masson Trichrome stain. The sections of the kidney showed that umbelliferone treatment decreased the glomerular damage, mesangial matrix expansion as well as the renal fibrosis. Determination of renal transforming growth factor beta one (TGF-β1) expression by immunohistochemical analysis, western blotting and circulating TGF-β1 by ELISA assay showed that umbelliferone decreased the renal tissue and circulating TGF-β1 level.

CONCLUSION

Umbelliferone treatment can significantly reduce the diabetes induced renal damage and can improve the pathological conditions related to the diabetic nephropathy by down regulation of TGF-β.

Transforming growth factor β1 enhances heme oxygenase 1 expression in human synovial fibroblasts by inhibiting microRNA 519b synthesis

Background

Osteoarthritis (OA) is manifested by synovial inflammation and cartilage destruction that is directly linked to synovitis, joint swelling and pain. In the light of the role of synovium in the pathogenesis and the symptoms of OA, synovium-targeted therapy is a promising strategy to mitigate the symptoms and progression of OA. Transforming growth factor beta 1 (TGF-β1), a secreted homodimeric protein, possesses unique and potent anti-inflammatory and immune-regulatory properties in many cell types. Heme oxygenase 1 (HO-1) is an inducible anti-inflammatory and stress responsive enzyme that has been proven to prevent injuries caused by many diseases. Despite the similar anti-inflammatory profile and their involvement in the pathogenesis of arthritic diseases, no studies have as yet explored the possibility of any association between the expression of TGF-β1 and HO-1.

Methodology/Principal findings

TGF-β1-induced HO-1 expression was examined by HO-1 promoter assay, qPCR, and Western blotting. The siRNAs and enzyme inhibitors were utilized to determine the intermediate involved in the signal transduction pathway. We showed that TGF-β1 stimulated the synthesis of HO-1 in a concentration- and time-dependent manner, which can be mitigated by blockade of the phospholipase (PLC)γ/protein kinase C alpha (PKC)α pathway. We also showed that the expression of miRNA-519b, which blocks HO-1 transcription, is inhibited by TGF-β1, and the suppression of miRNA 519b could be reversed via blockade of the PLCγ/PKCα pathway.

Conclusions/Significance

TGF-β1 stimulated the expression of HO-1 via activating the PLCγ/PKCα pathway and suppressing the downstream expression of miRNA-519b. These results may shed light on the pathogenesis and treatment of OA.

[Role of Inhibitory Transforming Growth Factor-β Signal Smad7 in Helicobacter pylori-associated Gastric Damage]

Background/Aims

Transforming growth factor-beta (TGF-β) is a cytokine implicated in the susceptibility, development, and progression of gastrointestinal cancer and certain other neoplasms. In the later stages of cancer, TGF-β not only acts as a bystander of host-immune response, but also contributes to cell growth, invasion, and metastasis. In the current study, we generated gastric mucosal cells that stably express Smad7, and explored the Helicobacter pylori-associated biological changes between mock-transfected and Smad7-transfected RGM1 cells.

Methods

RGM1 cells stably transfected with Smad7 were infected with H. pylori, and molecular changes in apoptotic markers and inflammatory mediators were examined. Several candidate genes were explored in Smad7-overexpressing cells after H. pylori infection.

Results

Overexpression of Smad7 in RGM1 cells significantly increased the H. pylori-induced cytotoxicity compared to mock-transfected cells. Exaggerated increases in inflammatory mediators, cyclooxygenase 2, inducible NO synthase, and augmented apoptosis were noted in Smad7-overexpressing cells, whereas mitigated heme oxygenase 1 was noted in Smad7- overexpressing cells. These phenomena were reversed in cells transfected with Smad7 siRNA.

Conclusions

These data suggest that inhibition of Smad7 is a possible target for mitigating H. pylori-associated inflammation.

Protective effects of allicin on streptozotocin-induced diabetic nephropathy in rats

BACKGROUND

Studies in animal models have shown that allicin, a major biologically active component of garlic, can play a role in the prevention of tissue fibrosis in the liver, lung and heart, mainly related to the inhibition of fibroblast proliferation, fibrogenic cytokine secretion and extracellular matrix synthesis. This study aimed to investigate the protective effects of allicin on renal damage in streptozotocin (STZ)-induced diabetic rats. STZ-induced diabetic rats were administered allicin (15, 30 and 45 mg · kg^-1  · day^-1 ) via daily intra-gastric gavage for 12 weeks. The levels of fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (sCr), lipid and 24 h urine albumin excretion (UAE) were measured at the end of weeks 4, 8 and 12. The renal histopathology and the expression levels of collagen I, transforming growth factor β1 (TGF-β1) and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) were measured using immunohistochemistry and/or western blotting.

RESULTS

In 12 week STZ-induced diabetic rats, severe hyperglycemia and albuminuria were markedly developed. Treatment with allicin for 12 weeks ameliorated diabetes-induced morphological alterations of the kidney and decreased FBG, BUN, sCr, triglyceride (TG) and 24 h UAE in diabetic rats. The expression levels of collagen I, TGF-β1 and p-ERK1/2 were significantly decreased by allicin treatment.

CONCLUSION

These results suggested that allicin may play a protective role in diabetic nephropathy via the TGF-β1/ERK pathway in diabetic rats. © 2016 Society of Chemical Industry.

Central Nodes in Protein Interaction Networks Drive Critical Functions in Transforming Growth Factor Beta-1 Stimulated Kidney Cells

Objective

Despite the huge efforts, chronic kidney disease (CKD) remains as an unsolved problem in medicine. Many studies have shown a central role for transforming growth factor beta-1 (TGFβ-1) and its downstream signaling cascades in the pathogenesis of CKD. In this study, we have reanalyzed a microarray dataset to recognize critical signaling pathways controlled by TGFβ-1.

Materials and Methods

This study is a bioinformatics reanalysis for a microarray data. The GSE23338 dataset was downloaded from the gene expression omnibus (GEO) database which assesses the mRNA expression profile of TGFβ-1 treated human kidney cells after 24 and 48 hours incubation. The protein interaction networks for differentially expressed (DE) genes in both time points were constructed and enriched. In addition, by network topology analysis, genes with high centrality were identified and then pathway enrichment analysis was performed with either the total network genes or with the central nodes.

Results

We found 110 and 170 genes differentially expressed in the time points 24 and 48 hours, respectively. As the genes in each time point had few interactions, the networks were enriched by adding previously known genes interacting with the differentially expressed ones. In terms of degree, betweenness, and closeness centrality parameters 62 and 60 nodes were considered to be central in the enriched networks of 24 hours and 48 hours treatment, respectively. Pathway enrichment analysis with the central nodes was more informative than those with all network nodes or even initial DE genes, revealing key signaling pathways.

Conclusion

We here introduced a method for the analysis of microarray data that integrates the expression pattern of genes with their topological properties in protein interaction networks. This holistic novel approach allows extracting knowledge from raw bulk omics data.

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

Renal fibrosis, irrespective of its etiology, is a final common stage of almost all chronic kidney diseases. Increased apoptosis, epithelial-to-mesenchymal transition, and inflammatory cell infiltration characterize the injured kidney. On the molecular level, transforming growth factor-β1 (TGF-β1)-Smad3 signaling pathway plays a central role in fibrotic kidney disease. Recent findings indicate the prominent role of microRNAs, small noncoding RNA molecules that inhibit gene expression through the posttranscriptional repression of their target mRNAs, in different pathologic conditions, including renal pathophysiology. miR-21 was also shown to play a dynamic role in inflammatory responses and in accelerating injury responses to promote organ failure and fibrosis. Understanding the cellular and molecular bases of miR-21 involvement in the pathogenesis of kidney diseases, including inflammatory reaction, could be crucial for their early diagnosis. Moreover, the possibility of influencing miR-21 level by specific antagomirs may be considered as an approach for treatment of renal diseases.

Smad7 protects against chronic aristolochic acid nephropathy in mice

Chronic Aristolochic Acid Nephropathy (AAN) is a progressive chronic kidney disease related to herb medicine. However, treatment for chronic AAN remains ineffective. We report here that Smad7 is protective and has therapeutic potential for chronic AAN. In a mouse model of chronic AAN, progressive renal injury was associated with a loss of renal Smad7 and disruption of Smad7 largely aggravated the severity of chronic AAN as demonstrated by a significant increase in levels of 24-hour urinary protein excretion, serum creatinine, and progressive renal fibrosis and inflammation. In contrast, restored Smad7 locally in the kidneys of Smad7 knockout mice prevented the progression of chronic AAN. Further studies revealed that worsen chronic AAN in Smad7 knockout mice was associated with enhanced activation of TGF-β/Smad3 and NF-κB signaling pathways, which was reversed when renal Smad7 was restored. Importantly, we also found that overexpression of Smad7 locally in the kidneys with established chronic AAN was capable of attenuating progressive chronic AAN by inactivating TGF-β/Smad3-medated renal fibrosis and NF-κB-driven renal inflammation. In conclusion, Smad7 plays a protective role in the pathogenesis of chronic AAN and overexpression of Smad7 may represent a novel therapeutic potential for chronic AAN.

Effect of transforming growth factor-β3 on the expression of Smad3 and Smad7 in tenocytes

Tendon adhesion is a common problem in the healing of injured tendons. The molecular mechanisms of the TGF-β/Smad signaling pathway have been determined, and the role of TGF-β has been well characterized in wound healing. However, the intracellular mechanism or downstream signals by which TGF-β3 modulates its effects on tendon healing have not been well elucidated. The aim of this study was to determine the effect of TGF‑β3 on the TGF-β/Smad signaling pathway in tenocytes. Quantitative polymerase chain reaction and western blot analysis were used to analyze the effect of TGF‑β3 on the regulation of the expression of Smad proteins in tenocytes. The results demonstrated that TGF‑β3 has no significant effect on the proliferation of tendon cells. The addition of TGF‑β3 to tenocytes can significantly downregulate the expression of Smad3 and upregulate the expression of Smad7 at the gene and protein levels. The results demonstrate that TGF‑β3 may regulate Smad3 and Smad7 proteins through the TGF-β/Smad signaling pathway to minimize extrinsic scarring. Thus, it may provide a novel approach to decrease tendon adhesion and promote tendon healing.

Role of Transforming Growth Factor-β1 and Smads Signaling Pathway in Intrauterine Adhesion

The aim of the study was to evaluate the role of Smad3, Smad7, and TGF-β1 in intrauterine adhesion (IUA) patients and experimental rabbit models. 60 IUA patients, 30 control participants, and 18 female rabbits were enrolled in this study. We found that the plasma concentrations and protein expressions of TGF-β1 were significantly increased in patients and experimental rabbits compared to those in controls (P < 0.05). Furthermore, the mRNA and protein expression levels of Smad3 were significantly elevated, while Smad7 level was markedly decreased in the patients and experimental rabbits compared with controls (P < 0.05). This altered ratio recommended that IUA was positively correlated to the mRNA and protein expression levels of Smad3, Smad7, and TGF-β1 in blood and uterine tissue. Moreover, we used the specific inhibitor of Smad3 (SIS3) in experimental rabbit. SIS3 obviously reduced the mRNA and protein expression of smad3 and TGF-β1, while it increased Smad7 expression in the treatment groups as compared with IUA rabbits (P < 0.05). Our study suggested that TGF-β1/Smad3/smad7 is a major pathway which plays an important role in the regulation of the IUA and specific inhibitor of Smad3 (SIS3) may provide a new therapeutic strategy for IUA.

Nanosized titanium dioxide resulted in the activation of TGF-β/Smads/p38MAPK pathway in renal inflammation and fibration of mice

Titanium dioxide nanoparticles (TiO2 NPs) have been demonstrated to damage the kidneys. However, whether chronic nephritis leads to renal fibration or the fibrosis is associated with the activation of TGF-β/Smads/p38MAPK pathway caused by TiO2 NPs exposure is not well understood. Forty male mice were separately exposed to 0, 2.5, 5, or 10 mg/kg body weight TiO2 NPs for 6 months. Renal biochemical functions and levels of TGF-β/Smads/p38MAPK pathway-related markers and extracellular matrix (ECM) expression in the kidneys were investigated. The findings showed that subchronic TiO2 NPs exposure increased levels of urinary creatisix (Cr), N-acetyl-glucosaminidase, and vanin-1, resulted in severe renal inflammation and fibration. Furthermore, TiO2 NP exposure upregulated expression of transforming growth factor-β1 (TGF-β1, 0.07- to 2.72-fold), Smad2 (0.42- to 1.63-fold), Smad3 (0.02- to 1.94-fold), ECM (0.15- to 2.75-fold), α-smooth muscle actin (0.14- to 3.06-fold), p38 mitogen-activated protein kinase (p38MAPK, 0.11- to 3.78-fold), and nuclear factor-κB (0.4- to 2.27-fold), and downregulated Smad7 (0.05- to 0.61-fold) expression in mouse kidney. Subchronic TiO2 NPs exposure induced changes of renal characteristics towards inflammation and fibration may be mediated via TGF-β/Smads/p38MAPK pathway, and the uses of TiO2 NPs should be carried out cautiously, especially in humans. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1452-1461, 2016.

Therapeutic Effects of Tangshen Formula on Diabetic Nephropathy in Rats

Objective

Inflammation and fibrosis are essential promoters in the pathogenesis of diabetic nephropathy (DN) in type 2 diabetes. The present study examined the anti-inflammation and anti-fibrosis effect of Tangshen Formula (TSF), a traditional Chinese medicine, on DN.

Research Design and Methods

Protective role of TSF in DN was examined in a rat model of type 2 DN that was established by high-fat diet-fed and low-dose-streptozotocin injection. TSF was suspended in 0.5% CMC-Na solution and delivered by oral gavage at a dosage of 1.67g/Kg body weight/day. The therapeutic effects and mechanisms of TSF on diabetic kidney injury were examined.

Results

We found that TSF treatment for 20 weeks attenuated DN by significantly inhibiting urinary excretion of albumin and renal histological injuries. These beneficial effects were associated with an inactivation of NF-κB signaling, thereby blocking the upregulation of pro-inflammatory cytokines (IL-1β, TNFα), chemokine (MCP-1), and macrophage infiltration in the TSF-treated rats with type 2 DN. In addition, TSF treatment also inactivated TGF-β/Smad3 signaling and therefore suppressed renal fibrosis including expressions of fibronectin, collagen I, and collagen IV. Further studies revealed that the inhibitory effect of TSF on TGF-β/Smad3 and NF-κB signaling in DN was associated with inhibition of Smurf2-dependent ubiquitin degradation of Smad7.

Conclusions

The present study reveals that TSF has therapeutic potential for type 2 DN in rats. Blockade of NF-κB-driven renal inflammation and TGF-β/Smad3-mediated renal fibrosis by preventing the Smurf2-mediated Smad7 degradation pathway may be mechanisms through which TSF inhibits type 2 DN.

TGF-β/SMAD Pathway and Its Regulation in Hepatic Fibrosis

Transforming growth factor-beta1 (TGF-β1), a key member in the TGF-β superfamily, plays a critical role in the development of hepatic fibrosis. Its expression is consistently elevated in affected organs, which correlates with increased extracellular matrix deposition. SMAD proteins have been studied extensively as pivotal intracellular effectors of TGF-β1, acting as transcription factors. In the context of hepatic fibrosis, SMAD3 and SMAD4 are pro-fibrotic, whereas SMAD2 and SMAD7 are protective. Deletion of SMAD3 inhibits type I collagen expression and blocks epithelial-myofibroblast transition. In contrast, disruption of SMAD2 upregulates type I collagen expression. SMAD4 plays an essential role in fibrosis disease by enhancing SMAD3 responsive promoter activity, whereas SMAD7 negatively mediates SMAD3-induced fibrogenesis. Accumulating evidence suggests that divergent miRNAs participate in the liver fibrotic process, which partially regulates members of the TGF-β/SMAD signaling pathway. In this review, we focus on the TGF-β/SMAD and other relative signaling pathways, and discussed the role and molecular mechanisms of TGF-β/SMAD in the pathogenesis of hepatic fibrosis. Moreover, we address the possibility of novel therapeutic approaches to hepatic fibrosis by targeting to TGF-β/SMAD signaling.

TGF-β signaling in the kidney: profibrotic and protective effects

Transforming growth factor-β (TGF-β) is generally considered as a central mediator of fibrotic diseases. Indeed, much focus has been placed on inhibiting TGF-β and its downstream targets as ideal therapeutic strategies. However, pharmacological blockade of TGF-β has not yet translated into successful therapy for humans, which may be due to pleiotropic effects of TGF-β signaling. Equally, TGF-β signaling as a protective response in kidney injury has been relatively underexplored. An emerging body of evidence from experimental kidney disease models indicates multifunctionality of TGF-β capable of inducing profibrotic and protective effects. This review discusses recent advances highlighting the diverse roles of TGF-β in promoting not only renal fibrosis but also protective responses of TGF-β signaling. We review, in particular, growing evidence that supports protective effects of TGF-β by mechanisms which include inhibiting inflammation and induction of autophagy. Additional detailed studies are required to fully understand the diverse mechanisms of TGF-β actions in renal fibrosis and inflammation that will likely direct toward effective antifibrotic therapies.

MicroRNA expression profiles differentiate chronic pain condition subtypes

Chronic pain is a significant health care problem, ineffectively treated because of its unclear etiology and heterogeneous clinical presentation. Emerging evidence demonstrates that microRNAs (miRNAs) regulate the expression of pain-relevant genes, yet little is known about their role in chronic pain. Here, we evaluate the relationship among pain, psychological characteristics, plasma cytokines, and whole blood miRNAs in 22 healthy controls (HCs); 33 subjects with chronic pelvic pain (vestibulodynia, VBD); and 23 subjects with VBD and irritable bowel syndrome (VBD + IBS). VBD subjects were similar to HCs in self-reported pain, psychological profiles, and remote bodily pain. VBD + IBS subjects reported decreased health and function; and an increase in headaches, somatization, and remote bodily pain. Furthermore, VBD subjects exhibited a balance in proinflammatory and anti-inflammatory cytokines, whereas VBD + IBS subjects failed to exhibit a compensatory increase in anti-inflammatory cytokines. VBD subjects differed from controls in expression of 10 miRNAs of predicted importance for pain and estrogen signaling. VBD + IBS subjects differed from controls in expression of 11 miRNAs of predicted importance for pain, cell physiology, and insulin signaling. miRNA expression was correlated with pain-relevant phenotypes and cytokine levels. These results suggest that miRNAs represent a valuable tool for differentiating VBD subtypes (localized pain with apparent peripheral neurosensory disruption vs widespread pain with a central sensory contribution) that may require different treatment approaches.

Effects and Mechanism of Combination of Rhein and Danshensu in the Treatment of Chronic Kidney Disease

Traditional Chinese medicine (TCM) plays a systemic role in disease treatment, targeting multiple etiological factors simultaneously. Based on clinical experience, rhubarb and Salvia miltiorrhiza are commonly prescribed together for the treatment of chronic kidney disease (CKD) and have been proven to be very effective. However, the rationale of the combination remains unclear. The major active ingredients of these two herbs are rhein (RH) and danshensu (DSS), respectively. The aim of this paper is to investigate the renoprotective effects of RH and DSS in vitro and in vivo, and the underlying mechanism. A total of 5/6 nephrectomy rats and HK-2 cells were subjected to chronic renal injury. The combination of RH and DSS conferred a protective effect, as shown by a significant improvement in the renal function, blood supply, and fibrotic degree. Proinflammatory cytokines and adhesion molecules were suppressed by RH and DSS through NK-κB signaling. The combination also inhibited apoptosis by up-regulating Bcl-2 and down-regulating Bax. Inhibiting the TGF-β/Smad3 pathway was at least in part involved in the antifibrotic mechanism of the combination treatment of RH and DSS. This study demonstrates for the first time the renoprotective effect and the mechanism of RH and DSS combination on chronic renal injury. It could provide experimental evidence to support the rationality of the combinatorial use of TCM in clinical practices.

Effect of paricalcitol and enalapril on renal inflammation/oxidative stress in atherosclerosis

AIM: To investigate the protective effect of paricalcitol and enalapril on renal inflammation and oxidative stress in ApoE-knock out mice.

METHODS: Animals treated for 4 mo as group (1) ApoE-knock out plus vehicle, group (2) ApoE-knock out plus paricalcitol (200 ng thrice a week), (3) ApoE-knock out plus enalapril (30 mg/L), (4) ApoE-knock out plus paricalcitol plus enalapril and (5) normal. Blood pressure (BP) was recorded using tail cuff method. The kidneys were isolated for biochemical assays using spectrophotometer and Western blot analyses.

RESULTS: ApoE-deficient mice developed high BP (127 ± 3 mmHg) and it was ameliorated by enalapril and enalapril plus paricalcitol treatments but not with paricalcitol alone. Renal malondialdehyde concentrations, p22^phox, manganese-superoxide dismutase, inducible nitric oxide synthase (NOS), monocyte chemoattractant protein-1, tumor necrosis factor-alpha and transforming growth factor-β1 levels significantly elevated but reduced glutathione, CuZn-SOD and eNOS levels significantly depleted in ApoE-knock out animals compared to normal. Administration of paricalcitol, enalapril and combined together ameliorated the renal inflammation and oxidative stress in ApoE-knock out animals.

CONCLUSION: Paricalcitol and enalapril combo treatment ameliorates renal inflammation as well as oxidative stress in atherosclerotic animals.

TGF-Beta Blockade Increases Renal Inflammation Caused by the C-Terminal Module of the CCN2

The CCN family member 2 (CCN2, also known as connective tissue growth factor) may behave as a risk biomarker and a potential therapeutic target for renal disease. CCN2 participates in the regulation of inflammation and fibrosis. TGF-β is considered the main fibrogenic cytokine; however, in some pathological settings TGF-β also has anti-inflammatory properties. CCN2 has been proposed as a downstream profibrotic mediator of TGF-β, but data on TGF-β role in CCN2 actions are scarce. Our aim was to evaluate the effect of TGF-β blockade in CCN2-mediated experimental renal damage. Systemic administration of the C-terminal module of CCN2 to mice caused sustained renal inflammation. In these mice, TGF-β blockade, using an anti-TGF-β neutralizing antibody, significantly increased renal expression of the NGAL (a kidney injury biomarker), kidney infiltration by monocytes/macrophages, and upregulation of MCP-1 expression. The anti-inflammatory effect of TGF-β seems to be mediated by a dysregulation of the systemic Treg immune response, shown by decreased levels of circulating CD4⁺/Foxp3⁺Treg cells. Our experimental data support the idea that TGF-β exerts anti-inflammatory actions in the kidney and suggest that it is not an optimal therapeutic target.

Tanshinone IIA attenuates renal fibrosis and inflammation via altering expression of TGF-β/Smad and NF-κB signaling pathway in 5/6 nephrectomized rats

PURPOSE

In traditional Chinese medicine, Tanshinone IIA is used to treat chronic kidney disease (CKD). However, its biological activity and mechanism of action in renal fibrosis and inflammation are not fully identified. The current study was conducted to determine the effects of Tanshinone IIA treatment on CKD by assessing potential modulation of the TGF-β/Smad and NF-κB signaling pathway.

METHODS

CKD was produced in rats by 5/6 nephrectomy. They were then divided into the following groups: control (sham operation); CKD (5/6 nephrectomy); 5/6 nephrectomy+Tanshinone IIA (10mg/kg in average, once a day for 16 weeks). Serum and urine samples were obtained from animals in each group, and serum creatinine (Scr), blood urea nitrogen (BUN) levels and 24h urinary protein excretion were measured. Tissue samples from the kidney were used for morphometric studies (Masson's trichrome). The expression of fibronectin protein and collagen types I, III, IV, and TGF-β, TNF-α, CXCL-1, MCP-1, RANTES mRNA were evaluated using immunohistochemistry and RT-PCR analysis; the TGF-β/Smad and NF-κB signaling pathway was detected by immunohistochemistry and Western blot analysis.

RESULTS

The following effects were observed in CKD rats treated with Tanshinone IIA: (1) marked improvements in Scr, and 24h urine protein excretion; (2) significant reductions in protein and mRNA levels of fibronectin, collagen III, and collagen IV and TNF-α, MCP-1, and CXCL-1; (3) significantly inhibited the TGF-β/Smad and NF-κB signaling activation.

CONCLUSIONS

These results suggest that Tanshinone IIA suppresses renal fibrosis and inflammation via altering expression of TGF-β/Smad and NF-κB pathway in the remnant kidney, thus supporting the potential of Tanshinone IIA as a new therapeutic agent for slowing the progression of CKD.

MicroRNAs in renal fibrosis

MicroRNAs (miRNAs) are endogenous short non-coding RNAs that regulate most of important cellular processes by inhibiting gene expression through the post-transcriptional repression of their target mRNAs. In kidneys, miRNAs have been associated in renal development, homeostasis, and physiological functions. Results from clinical and experimental animal studies demonstrate that miRNAs play essential roles in the pathogenesis of various renal diseases. Chronic kidney diseases (CKD) is characterized by renal fibrosis. Transforming growth factor beta (TGF-β) is recognized as a major mediator of renal fibrosis because it is able to stimulate the accumulation of extracellular matrix (ECM) proteins to impair normal kidney function. Recently, emerging evidence demonstrate the relationship between TGF-β signaling and miRNAs expression during renal diseases. TGF-β regulates expression of several microRNAs, such as miR-21, miR-192, miR-200, miR-433, and miR-29. MiR-21, miR-192, and miR-433 which are positively induced by TGF-β signaling play a pathological role in kidney diseases. In contrast, members in both miR-29 and miR-200 families which are inhibited by TGF-β signaling protect kidneys from renal fibrosis by suppressing the deposition of ECM and preventing epithelial-to-mesenchymal transition, respectively. Clinically, the presence of miRNAs in blood and urine has been examined to be early biomarkers for detecting renal diseases. From experimental animal studies of CKD, targeting microRNAs also provides evidence about therapeutic potential of miRNAs during renal diseases. Now, it comes to the stage to examine the exact mechanisms of miRNAs during the initiation and progression of renal diseases. Therefore, determining the function of miRNAs in renal fibrosis may facilitate the development of both early diagnosis and treatment of renal diseases.

Artemisinin analogue SM934 ameliorates the proteinuria and renal fibrosis in rat experimental membranous nephropathy

AIM

SM934 is a novel water-soluble artemisinin derivative with immunoregulatory activities that has been used to treat murine lupus nephritis. In the current study, we investigated the effects of SM934 on rat experimental membranous nephropathy.

METHODS

Passive Heymann nephritis (PHN) was induced in SD rats by intraperitoneal injection of anti-Fx1A serum. The rats were orally administered SM934 (12.5 and 25 mg·kg(-1)·d(-1)) or prednisolone (5 mg·kg(-1)·d(-1)) for 28 d. Blood and urine sample, and kidney tissue were collected for analyses. Human complement C3a-induced injury of HK-2 cells was used for in vitro experiments.

RESULTS

Treatment of PHN rats with SM934 or prednisolone attenuated the progression of glomerulonephritis and renal fibrosis, as evidenced by the reduced level of proteinuria and circulating antibodies, as well as by the reduced immune complex deposition, reversed podocyte injuries, and attenuated tubulointerstitial fibrosis in the kidneys. Furthermore, the two drugs suppressed TGF-β1 expression and Smad2/3 phosphorylation, and increased Smad7 expression in the kidneys. The two doses of SM934 produced almost identical therapeutic effects on PHN rats. Pretreatment with SM934 or a C3a receptor antagonist blocked the C3a-induced epithelial-mesenchymal transition in HK-2 cells in vitro.

CONCLUSION

SM934 ameliorates kidney injury and attenuates the tubulointerstitial fibrosis in PHN rats by down-regulation of the TGF-β1/Smad signaling pathway.

Latent transforming growth factor-β1 protects against bleomycin-induced lung injury in mice

Transforming growth factor (TGF)-β1 is a potent mediator known to induce lung fibrosis. However, the role of latent TGF-β1 in lung inflammation and fibrosis is unclear. To investigate the role of circulating latent TGF-β1 in bleomycin-induced lung injury, lung disease was induced in keratin-5 promoter-driven TGF-β1(wt) transgenic (Tg) mice by bleomycin. The role of latent TGF-β1 in pulmonary inflammation and fibrosis was examined at Days 7 and 28 after administration of bleomycin. Compared with littermate wild-type (WT) mice, TGF-β1(wt) Tg mice had over twofold-higher levels of latent TGF-β1 in both plasma and lung tissue, and were protected from bleomycin-induced pulmonary inflammation, such as up-regulation of IL-1β, TNF-α, and macrophage chemotactic protein-1, and infiltration of CD3(+) T cells and F4/80(+) macrophages. In addition, the severity of lung fibrosis with massive collagen matrix accumulation was markedly reduced in TGF-β1(wt) Tg mice. These protective effects were associated with higher levels of Smad7 and inactivation of both NF-κB and TGF-β/Smad3 signaling pathways, in addition to an increase in forkhead box P3 (Foxp3)-dependent regulatory T cells, but inhibition of T helper 17-mediated lung injury. In summary, mice overexpressing latent TGF-β1 are protected from bleomycin-induced lung injury. Triggering the Smad7 negative feedback mechanism to inhibit both NF-κB and TGF-β/Smad signaling pathways, and enhancing the regulatory T cell response to counter-regulate T helper 17-mediated lung injury, are potential mechanisms by which latent TGF-β1 protects against bleomycin-induced lung injury.