Nuclear factor (NF)-κB p65 regulates differentiation of human and mouse lung fibroblasts mediated by TGF-β

Discussion of the material basis for prevention and treatment of pulmonary fibrosis using naturally medicinal and edible homologous herbs based on the dynamic process of Nrf2, NF-κB and TGF-β in PF

Pulmonary fibrosis (PF) is a progressive chronic lung disease with a high incidence and poor prognosis. Despite extensive research into the mechanisms that initiate and drive the progression of pulmonary fibrosis, developing effective treatments remains challenging due to the multiple etiologies, pathogenic links, and signaling pathways involved in PF. Indeed, nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor kappa-B (NF-κB), and transforming growth factor-beta (TGF-β) are central players in the pathogenesis of pulmonary fibrosis, and each of these factors influences distinct yet interconnected processes that collectively contribute to disease progression: Nrf2 upregulates antioxidants to mitigate oxidative stress, NF-κB modulates inflammatory responses, and TGF-β promotes fibroblast activation and extracellular matrix (ECM) deposition, leading to fibrosis. Targeting these pathways may offer therapeutic strategies, uncover new insights and provide potential therapeutic targets for PF. Absolutely, the interactions between Nrf2, NF-κB, and TGF-β pathways are complex and can significantly influence the progression of PF, which indicated that targeting a single pathway may show poor efficacy in managing the condition. Moreover, few therapies that effectively intervene in these pathways have been approved. This review focused on the molecular mechanisms of Nrf2, NF-κB, and TGF-β involving in PF and the material basis of the naturally medicinal and edible homologous herbs, which provides a solid foundation for understanding the disease's pathogenesis, and supports the development of therapeutic drugs or treatments for addressing the complex nature of PF.

Aberrant Chitinase 3-Like 1 Expression in Basal Cells Contributes to Systemic Sclerosis Fibrosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by extensive skin and internal organ fibrosis. However, the mechanism underlying fibrosis remains unclear, and effective treatments for halting or reversing fibrosis are lacking. In this study, single-cell RNA sequencing is used to obtain a comprehensive overview of skin cells from patients with SSc and healthy controls. A subset of basal cells with high chitinase 3-like 1 (Chi3L1) expression, which potentially plays an important role in fibroblast activation, is identified in SSc. Subsequently, patients with SSc are present with increased expression of Chi3L1 in the skin and serum, and elevated serum levels are associated with skin induration and pulmonary function. Furthermore, Chi3L1 promoted the differentiation of SSc dermal fibroblasts into myofibroblasts, and Chi3L1-deficient (Chi3L1-/-) mice showed amelioration of fibrosis in a bleomycin-induced SSc (BLM-SSc) model. Mechanistically, Chi3L1 mediates fibroblast activation primarily by interacting with interleukin-17 receptor A (IL-17RA), thereby initiating downstream nuclear factor kappa B and mitogen-activated protein kinases signaling pathways. Moreover, the anti-fibrotic effect of IL-17RA antagonists in BLM-SSc mice is demonstrated. In conclusion, Chi3L1 is a potential biomarker for the degree of fibrosis in SSc. Chi3L1 and its receptor, IL-17RA, are promising therapeutic targets for patients with SSc.

The Use of Extracellular Vesicles in Achilles Tendon Repair: A Systematic Review

Achilles tendon (AT) pathologies are common musculoskeletal conditions that can significantly impair function. Despite various traditional treatments, recovery is often slow and may not restore full functionality. The use of extracellular vesicles (EVs) has emerged as a promising therapeutic option due to their role in cell signaling and tissue regeneration. This systematic review aims to consolidate current in vivo animal study findings on the therapeutic effects of EVs on AT injuries. An extensive literature search was conducted using the PubMed, Scopus, and Embase databases for in vivo animal studies examining the effects of EVs on AT pathologies. The extracted variables included but were not limited to the study design, type of EVs used, administration methods, efficacy of treatment, and proposed therapeutic mechanisms. After screening, 18 studies comprising 800 subjects were included. All but one study reported that EVs augmented wound healing processes in the AT. The most proposed mechanisms through which this occurred were gene regulation of the extracellular matrix (ECM), the enhancement of macrophage polarization, and the delivery of therapeutic microRNAs to the injury site. Further research is warranted to not only explore the therapeutic potential of EVs in the context of AT pathologies, but also to establish protocols for their clinical application.

Unraveling the interplay between vital organelle stress and oxidative stress in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease characterized by excessive accumulation of extracellular matrix, leading to irreversible fibrosis. Emerging evidence suggests that endoplasmic reticulum (ER) stress, mitochondrial stress, and oxidative stress pathways play crucial roles in the pathogenesis of IPF. ER stress occurs when the protein folding capacity of the ER is overwhelmed, triggering the unfolded protein response (UPR) and contributing to protein misfolding and cellular stress in IPF. Concurrently, mitochondrial dysfunction involving dysregulation of key regulators, including PTEN-induced putative kinase 1 (PINK1), Parkin, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and sirtuin 3 (SIRT3), disrupts mitochondrial homeostasis and impairs cellular energy metabolism. This leads to increased reactive oxygen species (ROS) production, release of pro-fibrotic mediators, and activation of fibrotic pathways, exacerbating IPF progression. The UPR-induced ER stress further disrupts mitochondrial metabolism, resulting in altered mitochondrial mechanisms that increase the generation of ROS, resulting in further ER stress, creating a feedback loop that contributes to the progression of IPF. Oxidative stress also plays a pivotal role in IPF, as ROS-mediated activation of TGF-β, NF-κB, and MAPK pathways promotes inflammation and fibrotic responses. This review mainly focuses on the links between ER stress, mitochondrial dysfunctions, and oxidative stress with different signaling pathways involved in IPF. Understanding these mechanisms and targeting key molecules within these pathways may offer promising avenues for intervention.

New tricks for old drugs- praziquantel ameliorates bleomycin-induced pulmonary fibrosis in mice

BACKGROUND

Pulmonary fibrosis is a chronic progressive disease with complex pathogenesis, short median survival time, and high mortality. There are few effective drugs approved for pulmonary fibrosis treatment. This study aimed to evaluate the effect of praziquantel (PZQ) on bleomycin (BLM)-induced pulmonary fibrosis.

METHODS

In this study, we investigated the role and mechanisms of PZQ in pulmonary fibrosis in a murine model induced by BLM. Parameters investigated included survival rate, lung histopathology, pulmonary collagen deposition, mRNA expression of key genes involved in pulmonary fibrosis pathogenesis, the activity of fibroblast, and M2/M1 macrophage ratio.

RESULTS

We found that PZQ improved the survival rate of mice and reduced the body weight loss induced by BLM. Histological examination showed that PZQ significantly inhibited the infiltration of inflammatory cells, collagen deposition, and hydroxyproline content in BLM-induced mice. Besides, PZQ reduced the expression of TGF-β and MMP-12 in vivo and inhibited the proliferation of fibroblast induced by TGF-β in vitro. Furthermore, PZQ affected the balance of M2/M1 macrophages.

CONCLUSIONS

Our study demonstrated that PZQ could ameliorate BLM-induced pulmonary fibrosis in mice by affecting the balance of M2/M1 macrophages and suppressing the expression of TGF-β and MMP-12. These findings suggest that PZQ may act as an effective anti-fibrotic agent for preventing the progression of pulmonary fibrosis.

Baicalein attenuates bleomycin-induced lung fibroblast senescence and lung fibrosis through restoration of Sirt3 expression

CONTEXT

Fibroblast senescence was reported to contribute to the pathological development of idiopathic pulmonary fibrosis (IPF), and baicalein is reported to attenuate IPF.

OBJECTIVE

This study explores whether baicalein attenuates lung fibrosis by regulating lung fibroblast senescence.

MATERIALS AND METHODS

Institute of Cancer Research (ICR) mice were randomly assigned to control, bleomycin (BLM), baicalein and BLM + baicalein groups. Lung fibrosis was established by a single intratracheal dose of BLM (3 mg/kg). The baicalein group received baicalein orally (100 mg/kg/day). Sirtuin 3 (Sirt3) siRNA (50 μg) was injected through the tail vein once a week for 2 weeks to explore its effect on the anti-pulmonary fibrosis of baicalein.

RESULTS

BLM-treated mice exhibited obvious lung fibrosis and fibroblast senescence by showing increased levels of collagen deposition (27.29% vs. 4.14%), hydroxyproline (208.05 vs. 40.16 ng/mg), collagen I (25.18 vs. 9.15 μg/mg), p53, p21, p16, MCP-1, PAI-1, TNF-α, MMP-10 and MMP-12 in lung tissues, which were attenuated by baicalein. Baicalein also mitigated BLM-mediated activation of TGF-β1/Smad signalling pathway. Baicalein restored the BLM-induced downregulation of Sirt3 expression in lung tissues and silencing of Sirt3 abolished the inhibitory role of baicalein against BLM-induced lung fibrosis, fibroblast senescence and activation of TGF-β1/Smad signalling pathway.

CONCLUSIONS

Baicalein preserved the BLM-induced downregulation of lung Sirt3 expression, and thus the suppression of TGF-β1/Smad signalling pathway and lung fibrosis, which might provide an experimental basis for treatment of IPF.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

Exploratory analysis to predict pneumonitis during durvalumab consolidation therapy for patients with locally advanced non-small cell lung cancer from proteomic profiling of circulating extracellular vesicles

BACKGROUND

Risk factors for predicting pneumonitis during durvalumab consolidation after chemoradiotherapy (CRT) in locally advanced non-small cell lung cancer (LA-NSCLC) are still lacking. Extracellular vesicles (EVs) play a crucial role in intercellular communication and are potential diagnostic tools for various diseases.

METHODS

We retrospectively collected predurvalumab treatment serum samples from patients treated with durvalumab for LA-NSCLC, isolated EVs using anti-CD9 and anti-CD63 antibodies, and performed proteomic analyses. We examined EV proteins that could predict the development of symptomatic pneumonitis (SP) during durvalumab treatment. Potential EV-protein biomarkers were validated in an independent cohort.

RESULTS

In the discovery cohort, 73 patients were included, 49 with asymptomatic pneumonitis (AP) and 24 with SP. Of the 5797 proteins detected in circulating EVs, 33 were significantly elevated (fold change [FC] > 1.5, p < 0.05) in the SP group, indicating enrichment of the nuclear factor kappa B (NF-κB) pathway. Patients with high levels of EV-RELA, an NF-κB subunit, had a higher incidence of SP than those with low levels of EV-RELA (53.8% vs. 13.4%, p = 0.0017). In the receiver operating characteristic analysis, EV-RELA demonstrated a higher area under the curve (AUC) than lung V20 (0.76 vs. 0.62) and was identified as an independent risk factor in the multivariate logistic regression analysis (p = 0.008, odds ratio 7.72). Moreover, high EV-RELA was also a predictor of SP in the validation cohort comprising 43 patients (AUC of 0.80).

CONCLUSIONS

Circulating EV-RELA may be a predictive marker for symptomatic pneumonitis in patients with LA-NSCLC treated with durvalumab.

Association of vitamin D status with COVID-19 and its severity : Vitamin D and COVID-19: a narrative review

Vitamin D is associated with biological activities of the innate and adaptive immune systems, as well as inflammation. In observational studies, an inverse relationship has been found between serum 25-hydroxyvitamin D (25(OH)D) concentrations and the risk or severity of coronavirus disease 2019 (COVID-19). Several mechanisms have been proposed for the role of vitamin D in COVID-19, including modulation of immune and inflammatory responses, regulation of the renin-angiotensin-aldosterone system, and involvement in glucose metabolism and cardiovascular system. Low 25(OH)D concentrations might predispose patients with COVID-19 to severe outcomes not only via the associated hyperinflammatory syndrome but also by worsening preexisting impaired glucose metabolism and cardiovascular diseases. Some randomized controlled trials have shown that vitamin D supplementation is beneficial for reducing severe acute respiratory syndrome coronavirus 2 RNA positivity but not for reducing intensive care unit admission or all-cause mortality in patients with moderate-to-severe COVID-19. Current evidence suggests that taking a vitamin D supplement to maintain a serum concentration of 25(OH)D of at least 30 ng/mL (preferred range 40-60 ng/mL), can help reduce the risk of COVID-19 and its severe outcomes, including mortality. Although further well designed studies are warranted, it is prudent to recommend vitamin D supplements to people with vitamin D deficiency/insufficiency during the COVID-19 pandemic according to international guidelines.

Nifuroxazide-loaded cubosomes exhibit an advancement in pulmonary delivery and attenuate bleomycin-induced lung fibrosis by regulating the STAT3 and NF-κB signaling: A new challenge for unmet therapeutic needs

Pulmonary fibrosis (PF) is a chronic progressive disease that portends a very poor prognosis. It has been suggested that STAT3 is a potential target in PF. This study highlights the importance of cubosomes as a drug delivery system in enhancing the bioavailability of nifuroxazide (NXZD), a poorly soluble STAT3 inhibitor. NXZD-loaded cubosomes (NXZD-LC) were in vitro and in vivo evaluated. In vitro, cubosomes presented a poly-angular nanosized particles with a mean size and zeta potential of 223.73 ± 4.73 nm and - 20.93 ± 2.38 mV, respectively. The entrapment efficiency of nifuroxazide was 90.56 ± 4.25%. The in vivo pharmacokinetic study and the lung tissue accumulation of NXZD were performed by liquid chromatography-tandem mass spectrometry after oral administration to rats. The nanoparticles exhibited a two-fold increase and 1.33 times of bioavailability and lung tissue concentration of NXZD compared to NXZD dispersion, respectively. In view of this, NXZD-LC effectively attenuated PF by targeting STAT3 and NF-κB signals. As a result, NXZD-LC showed a potential anti-inflammatory effect as revealed by the significant decrease in MCP-1, ICAM-1, IL-6, and TNF-α and suppressed fibrogenic mediators as indicated by the significant reduction in TGF-β, TIMP-1, and PDGF-BB in lung tissues. Besides, NXZD-LC improved antioxidant defense mechanisms and decreased LDH and BALF total protein. These effects contributed to decreased collagen deposition. To conclude, cubosomes represent an advantageous pharmaceutical delivery system for enhancing pulmonary delivery of poorly soluble drugs. Additionally, repurposing NXZD as an antifibrotic agent is a promising challenge and new therapeutic approach for unmet therapeutic needs.

Aryl Hydrocarbon Receptor Mechanisms Affecting Chronic Kidney Disease

The aryl hydrocarbon receptor (AHR) is a basic helix-loop-helix transcription factor that binds diverse endogenous and xenobiotic ligands, which regulate AHR stability, transcriptional activity, and cell signaling. AHR activity is strongly implicated throughout the course of chronic kidney disease (CKD). Many diverse organic molecules bind and activate AHR and these ligands are reported to either promote glomerular and tubular damage or protect against kidney injury. AHR crosstalk with estrogen, peroxisome proliferator-activated receptor-γ, and NF-κB pathways may contribute to the diversity of AHR responses during the various forms and stages of CKD. The roles of AHR in kidney fibrosis, metabolism and the renin angiotensin system are described to offer insight into CKD pathogenesis and therapies.

Inhibition of nuclear factor κB in the lungs protect bleomycin-induced lung fibrosis in mice

BACKGROUND

Pulmonary fibrosis is a debilitating condition with limited therapeutic avenues. The pathogenicity of pulmonary fibrosis constitutes involvement of cellular proliferation, activation, and transformational changes of fibroblast to myofibroblasts. It is a progressive lung disease and is primarily characterized by aberrant accumulation of extracellular matrix proteins in the lungs with poor prognosis. The inflammatory response in the pathogenesis of lung fibrosis is suggested because of release of several cytokines; however, the underlying mechanism remains undefined. A genetic model is the appropriate way to delineate the underlying mechanism of pulmonary fibrosis.

METHODS AND RESULTS

In this report, we have used cc-10 promoter based IκBα mutant mice (IKBM, an inhibitor of NF-κB) which were challenged with bleomycin (BLM). Compared to wild-type (WT) mice, the IKBM mice showed significant reduction in several fibrotic, vascular, and inflammatory genes. Moreover, we have identified a new set of dysregulated microRNAs (miRNAs) by miRNA array analysis in BLM-induced WT mice. Among these miRNAs, let-7a-5p and miR-503-5p were further analyzed. Our data showed that these two miRNAs were upregulated in WT-BLM and were reduced in IKBM-BLM mice. Bioinformatic analyses showed that let-7a-5p and miR-503-5p target for endothelin1 and bone morphogenic receptor 1A (BMPR1A), respectively, and were downregulated in WT-BLM mice indicating a link in pulmonary fibrosis.

CONCLUSION

We concluded that inhibition of NF-κB and modulation of let-7a-5p and miR-503-5p contribute a pivotal role in pulmonary fibrosis and may be considered as possible therapeutic target for the clinical management of lung fibrosis.

Latent Transforming Growth Factor-β Binding Protein-2 Regulates Lung Fibroblast-to-Myofibroblast Differentiation in Pulmonary Fibrosis via NF-κB Signaling

Despite past extensive studies, the mechanisms underlying pulmonary fibrosis (PF) still remain poorly understood. The aberrantly activated lung myofibroblasts, predominantly emerging through fibroblast-to-myofibroblast differentiation, are considered to be the key cells in PF, resulting in excessive accumulation of extracellular matrix (ECM). Latent transforming growth factor-β (TGFβ) binding protein-2 (LTBP2) has been suggested as playing a critical role in modulating the structural integrity of the ECM. However, its function in PF remains unclear. Here, we demonstrated that lungs originating from different types of patients with PF, including idiopathic PF and rheumatoid arthritis-associated interstitial lung disease, and from mice following bleomycin (BLM)-induced PF were characterized by increased LTBP2 expression in activated lung fibroblasts/myofibroblasts. Moreover, serum LTBP2 was also elevated in patients with COVID-19-related PF. LTBP2 silencing by lentiviral shRNA transfection protected against BLM-induced PF and suppressed fibroblast-to-myofibroblast differentiation in vivo and in vitro. More importantly, LTBP2 overexpression was able to induce differentiation of lung fibroblasts to myofibroblasts in vitro, even in the absence of TGFβ1. By further mechanistic analysis, we demonstrated that LTBP2 silencing prevented fibroblast-to-myofibroblast differentiation and subsequent PF by suppressing the phosphorylation and nuclear translocation of NF-κB signaling. LTBP2 overexpression-induced fibroblast-to-myofibroblast differentiation depended on the activation of NF-κB signaling in vitro. Therefore, our data indicate that intervention to silence LTBP2 may represent a promising therapy for PF.

DNA-coated gold nanoparticles for tracking hepatocyte growth factor secreted by transplanted mesenchymal stem cells in pulmonary fibrosis therapy

The identification of paracrine factors secreted by transplanted mesenchymal stem cells (MSCs) during the treatment of idiopathic pulmonary fibrosis (IPF) is essential for understanding the role of MSCs in therapy. Herein, we report a facile and efficient strategy for in vivo tracking the secretion of hepatocyte growth factor (HGF) in MSCs during IPF therapy. In our strategy, a novel nanoflare tracer consisting of gold nanoparticles (AuNPs), complementary sequences and dye-labeled recognition sequences is developed. Briefly, the AuNPs are functionalized with oligonucleotide complementary sequences hybridized to the organic dye-labeled recognition sequences, where the organic fluorophores are in close proximity to the AuNPs. In the absence of targets, the dye and AuNPs are separated from each other, inducing the quenching of the fluorescence signal. However, in the presence of targets, the recognition sequences gradually fall off from the AuNPs, causing the fluorescence signal to rise. In brief, in vivo monitoring of the dynamic expression of HGF mRNA in transplanted MSCs during IPF therapy in the current work may provide new insight into the paracrine process of the transplanted MSCs, thereby advancing the MSC-based IPF therapy toward clinical applications.

Montelukast, Leukotriene Inhibitor, Reduces LPS-Induced Acute Lung Inflammation and Human Neutrophil Activation

OBJECTIVES

Some pro-inflammatory lipids derived from 1 lipooxygenase enzyme are potent neutrophil chemoattractant, a cell centrally involved in acute respiratory distress syndrome (ARDS); a syndrome lacking effective treatment. Considering the beneficial effects of the leukotriene receptor inhibitor, montelukast, on other lung diseases, whether montelukast attenuates inflammation in a mouse model of ARDS, and whether it reduces LPS stimulated activation of human neutrophils was investigated.

METHODS

Thirty-five C57Bl/6 mice were distributed into control (PBS)+24h, LPS+24h (10μg/mouse), control+48h, LPS+48h, and LPS 48h+Montelukast (10mg/kg). In addition, human neutrophils were incubated with LPS (1μg/mL) and treated with montelukast (10μM).

RESULTS

Oral-tracheal administration of montelukast significantly attenuated total cells (P<.05), macrophages (P<.05), neutrophils (P<.01), lymphocytes (P<.001) and total protein levels in BAL (P<.05), as well as IL-6 (P<.05), CXCL1/KC (P<.05), IL-17 (P<.05) and TNF-α (P<.05). Furthermore, montelukast reduced neutrophils (P<.001), lymphocytes (P<.01) and macrophages (P<.01) in the lung parenchyma. In addition, montelukast restored BAL VEGF levels (P<.05). LTB4 receptor expression (P<.001) as well as NF-κB (P<.001), a downstream target of LPS, were also reduced in lung parenchymal leukocytes. Furthermore, montelukast reduced IL-8 (P<.001) production by LPS-treated human neutrophils.

CONCLUSION

In conclusion, montelukast efficiently attenuated both LPS-induced lung inflammation in a mouse model of ARDS and in LPS challenged human neutrophils.

Sirtuin 6 inhibits myofibroblast differentiation via inactivating transforming growth factor-β1/Smad2 and nuclear factor-κB signaling pathways in human fetal lung fibroblasts

Fibroblast-to-myofibroblast differentiation, which is characterized by increased expression of α-smooth muscle actin, is known to be involved in the pathogenesis of idiopathic pulmonary fibrosis. Sirtuin 6 (SIRT6), a member of the sirtuin family, has been proved to inhibit epithelial-to-mesenchymal transition during idiopathic pulmonary fibrosis. However, the function of SIRT6 in lung myofibroblast differentiation is still obscure. Transforming growth factor-β1 (TGF-β1) is one of the main factors that can powerfully promote myofibroblast differentiation. In the current study, we aimed to explore the role of SIRT6 in the cellular model of fibroblast-to-myofibroblast differentiation induced by TGF-β1 using human fetal lung fibroblasts (HFL1). We demonstrated that the SIRT6 protein level is upregulated by TGF-β1 in HFL1 cells. Overexpression of SIRT6 significantly suppresses TGF-β1-induced myofibroblast differentiation in HFL1 cells. Mechanistically, SIRT6 decreases phosphorylation and nuclear translocation of Smad2 under TGF-β1 stimulation. Nevertheless, mutant SIRT6 (H133Y) without histone deacetylase activity fails to inhibit phosphorylation and nuclear translocation of Smad2. Meanwhile, SIRT6 interacts with the nuclear factor-κB (NF-κB) subunit p65 and represses TGF-β1-induced NF-κB-dependent transcriptional activity, which is also dependent on its deacetylase activity. Overexpression of wild-type SIRT6 but not the H133Y mutant inhibits the expression of NF-κB-dependent genes including interleukin (IL)-1β, IL-6 and matrix metalloproteinase-9 (MMP-9) induced by TGF-β1, all of which have been demonstrated to promote myofibroblast differentiation. Collectively, our study reveals that SIRT6 prevents TGF-β1-induced lung myofibroblast differentiation through inhibiting TGF-β1/Smad2 and NF-κB signaling pathways.

Let-7e inhibits TNF-α expression by targeting the methyl transferase EZH2 in DENV2-infected THP-1 cells

Tumor necrosis factor α (TNFα), an important inflammatory cytokine, is associated with dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), a severe pathological manifestation of dengue virus (DENV) infection. However, the regulatory mechanism of microRNA on TNFα is currently unknown. Our study showed that the TNFα expression increased immediately and then later decreased, while a marked increase for the miRNA let-7e was detected in dengue virus type 2 (DENV2)-infected peripheral blood mononuclear cells (PBMCs). From this study, we found that let-7e was able to inhibit TNFα expression, but bioinformatics analysis showed that the enhancer of zeste homolog 2 (EZH2) was the potential direct target of let-7e instead of TNFα. EZH2 methyl transferase can produce H3K27me3 and has a negative regulatory role. Using a dual-luciferase reporter assay and Western blotting, we confirmed that EZH2 was a direct target of let-7e and found that siEZH2 could inhibit TNFα expression. In the further study of the regulatory mechanism of EZH2 on TNFα expression, we showed that siEZH2 promoted EZH1 and H3K4me3 expression and inhibited H3K27me3 expression. More importantly, we revealed that siEZH2 down-regulated NF-κB p65 within the nucleus. These findings indicate that the let-7e/EZH2/H3K27me3/NF-κB p65 pathway is a novel regulatory axis of TNFα expression. In addition, we determined the protein differences between siEZH2 and siEZH2-NC by iTRAQ and found a number of proteins that might be associated with TNFα.

Safer approaches to therapeutic modulation of TGF-β signaling for respiratory disease

The transforming growth factor (TGF)-β cytokines play a central role in development and progression of chronic respiratory diseases. TGF-β overexpression in chronic inflammation, remodeling, fibrotic process and susceptibility to viral infection is established in the most prevalent chronic respiratory diseases including asthma, COPD, lung cancer and idiopathic pulmonary fibrosis. Despite the overwhelming burden of respiratory diseases in the world, new pharmacological therapies have been limited in impact. Although TGF-β inhibition as a therapeutic strategy carries great expectations, the constraints in avoiding compromising the beneficial pleiotropic effects of TGF-β, including the anti-proliferative and immune suppressive effects, have limited the development of effective pharmacological modulators. In this review, we focus on the pathways subserving deleterious and beneficial TGF-β effects to identify strategies for selective modulation of more distal signaling pathways that may result in agents with improved safety/efficacy profiles. Adverse effects of TGF-β inhibitors in respiratory clinical trials are comprehensively reviewed, including those of the marketed TGF-β modulators, pirfenidone and nintedanib. Precise modulation of TGF-β signaling may result in new safer therapies for chronic respiratory diseases.

Long-Term Effects of TCM Yangqing Kangxian Formula on Bleomycin-Induced Pulmonary Fibrosis in Rats via Regulating Nuclear Factor-κB Signaling

Objective

We aimed to evaluate the therapeutic effects and long-term effects of YKF and dissect the potential mechanisms.

Materials and Methods

IPF rats were given YKF, prednisone, or pirfenidone, respectively, from day 1 to day 42, followed by a 28-day nonintervention interval through day 70. Forced vital capacity (FVC), histopathology, hydroxyproline (HYP) contents, lung coefficient, blood inflammatory cell populations, inflammatory cytokine levels of the lung tissues, and the expression of proteins involved in nuclear factor- (NF-) κB signaling pathway were evaluated on days 7, 14, 28, 42, and 70.

Results

HYP contents, Ashcroft scores, lung coefficient, and pulmonary fibrosis blood cell populations increased significantly in IPF rats, while FVC declined. All the above-mentioned parameters were improved in treatment groups from day 7 up to day 70, especially in YKF group. The mRNA and protein expressions of tumor necrosis factor- (TNF-) α significantly decreased, while interferon- (IFN-) γ significantly increased, and phosphorylations of cytoplasm inhibitor of nuclear factor kappa-B kinase β (IKKβ), inhibitor of nuclear factor kappa-B α (IκBα), and NF-κB were obviously downregulated in YKF group from day 7 to day 70.

Conclusion

YKF has beneficial protective and long-term effects on pulmonary fibrosis by anti-inflammatory response and alleviating fibrosis.

TIAM1 inhibits lung fibroblast differentiation in pulmonary fibrosis

The differentiation of fibroblasts to myofibroblasts is critical for the development of idiopathic pulmonary fibrosis (IPF). T-cell lymphoma invasion and metastasis 1 (TIAM1) is known to be associated with amyotrophic lateral sclerosis 1 and colorectal cancer; however, its role in IPF is unclear. The aim of the present study was to investigate the expression and roles of TIAM1 in lung fibroblasts during pulmonary fibrosis. It was demonstrated that TIAM1 expression was significantly increased in fibrotic lung tissue and lung fibroblasts from bleomycin (BLM)-treated mice compared with control mice (P<0.05). TIAM1 expression and differentiation were significantly upregulated in human lung fibroblasts challenged with transforming growth factor-β (TGF-β) compared with unchallenged cells (P<0.05). Furthermore, inhibition of the nuclear factor (NF)-κB signaling pathway significantly attenuated TGF-β-induced TIAM1 expression and decreased fibroblast differentiation in human lung fibroblasts (P<0.05). Similarly, overexpression of TIAM1 significantly inhibited TGF-β-induced fibroblast differentiation, as indicated by decreased expression of fibronectin and α-smooth muscle actin (SMA; P<0.05). The results of the present study also demonstrated that TIAM1 knockdown increased TGF-β-induced fibroblast differentiation (P<0.05). These findings suggest that TIAM1 expression is associated with lung fibroblast differentiation in pulmonary fibrosis via an NF-κB-dependent pathway, and that TIAM1 inhibits lung fibroblast differentiation in pulmonary fibrosis.

TNF-α-induced NF-κB activation promotes myofibroblast differentiation of LR-MSCs and exacerbates bleomycin-induced pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible lung disease of unknown cause. It has been reported that both lung resident mesenchymal stem cells (LR-MSCs) and tumor necrosis factor-α (TNF-α) play important roles in the development of pulmonary fibrosis. However, the underlying connections between LR-MSCs and TNF-α in the pathogenesis of pulmonary fibrosis are still elusive. In this study, we found that the pro-inflammatory cytokine TNF-α and the transcription factor nuclear factor kappa B (NF-κB) p65 subunit were both upregulated in bleomycin-induced fibrotic lung tissue. In addition, we discovered that TNF-α promotes myofibroblast differentiation of LR-MSCs through activating NF-κB signaling. Interestingly, we also found that TNF-α promotes the expression of β-catenin. Moreover, we demonstrated that suppression of the NF-κB signaling could attenuate myofibroblast differentiation of LR-MSCs and bleomycin-induced pulmonary fibrosis which were accompanied with decreased expression of β-catenin. Our data implicates that inhibition of the NF-κB signaling pathway may provide a therapeutic strategy for pulmonary fibrosis, a disease that warrants more effective treatment approaches.

Inhibition of IκB Kinase at 24 Hours After Acute Kidney Injury Improves Recovery of Renal Function and Attenuates Fibrosis

Background

Acute kidney injury (AKI) is a major risk factor for the development of chronic kidney disease. Nuclear factor‐κB is a nuclear transcription factor activated post‐ischemia, responsible for the transcription of proinflammatory proteins. The role of nuclear factor‐κB in the renal fibrosis post‐AKI is unknown.

Methods and Results

We used a rat model of AKI caused by unilateral nephrectomy plus contralateral ischemia (30 minutes) and reperfusion injury (up to 28 days) to show impairment of renal function (peak: 24 hours), activation of nuclear factor‐κB (peak: 48 hours), and fibrosis (28 days). In humans, AKI is diagnosed by a rise in serum creatinine. We have discovered that the IκB kinase inhibitor IKK16 (even when given at peak serum creatinine) still improved functional and structural recovery and reduced myofibroblast formation, macrophage infiltration, transforming growth factor‐β expression, and Smad2/3 phosphorylation. AKI resulted in fibrosis within 28 days (Sirius red staining, expression of fibronectin), which was abolished by IKK16. To confirm the efficacy of IKK16 in a more severe model of fibrosis, animals were subject to 14 days of unilateral ureteral obstruction, resulting in tubulointerstitial fibrosis, myofibroblast formation, and macrophage infiltration, all of which were attenuated by IKK16.

Conclusions

Inhibition of IκB kinase at peak creatinine improves functional recovery, reduces further injury, and prevents fibrosis.

Galunisertib (LY2157299), a transforming growth factor-β receptor I kinase inhibitor, attenuates acute pancreatitis in rats

Galunisertib (LY2157299), a selective ATP-mimetic inhibitor of TGF-β receptor I (TGF-βRI), is the only known TGF-β pathway inhibitor. In the present study, we investigated the effect of galunisertib on taurocholate (TAC)-induced acute pancreatitis (AP) in rats, and the role of TGF-β and NF-κB signaling pathways. AP was induced by infusion of TAC into the pancreatic duct of Sprague-Dawley male rats (n=30). The rats (220±50 g) were administered galunisertib intragastrically [75 mg·kg^-1·day^-1 for 2 days (0 and 24 h)]. Serum IL-1β, IL-6, TNF-α, amylase (AMY), lipase (LIP), and myeloperoxidase (MPO) levels were measured by ELISA. NF-κB activity was detected by electrophoretic mobility shift assay (EMSA); NF-κBp65 and TGF-β1 proteins, as well as TGF-βRI and p-Smad2/3 proteins, were detected by western blot assay. Cell apoptosis was detected by TUNEL assay. H&E staining was used to evaluate the histopathological alterations of the pancreas. Galunisertib treatment attenuated the severity of AP and decreased the pancreatic histological score. In addition, number of apoptotic cells were significantly increased in the galunisertib-treated group (16.38±2.26) than in the AP group (8.14±1.27) and sham-operated group (1.82±0.73; P<0.05 and P<0.01, respectively). Galunisertib decreased the expression levels of TGF-βRI and p-Smad2/3 and inhibited NF-κB activation and p65 translocation compared with the sham-operated group. Furthermore, serum IL-1β, IL-6, TNF-α, AMY and LIP levels and tissue MPO activity were significantly decreased in the galunisertib-treated group. Our data demonstrate that galunisertib attenuates the severity of TAC-induced experimental AP in rats by inducing apoptosis in the pancreas, inhibiting the activation of TGF-β signals and NF-κB as well as the secretion of pro-inflammatory cytokines.

Mogroside IIIE, a Novel Anti-Fibrotic Compound, Reduces Pulmonary Fibrosis through Toll-Like Receptor 4 Pathways

Idiopathic pulmonary fibrosis is a progressive fibrotic lung disease, and eventually most patients develop respiratory failure with a median survival rate of 2 to 3 years after diagnosis due to the lack of clinically effective therapies. Mogroside IIIE (MGIIIE), a cucurbitane-type compound, was isolated from Siraitia grosvenorii MGIIIE has shown the strongest inhibition of nitric oxide release, a crucial inflammatory factor, from lipopolysaccharide (LPS)-treated RAW264.7 cells compared with other mogrosides. In the pulmonary fibrosis mouse model induced by bleomycin, MGIIIE treatment attenuated pulmonary fibrosis, indicated as a reduction in myeloperoxidase activity, collagen deposition, and pathologic score. MGIIIE also significantly suppressed expression of several important fibrotic markers, e.g., α-smooth muscle actin, collagen I, transforming growth factor-β (TGF-β) signal, and metalloproteinases-9/tissue inhibitor of metalloproteinase-1. Furthermore, MGIIIE blocked tansdifferentiation of lung resident fibroblasts into myofibroblast-like cells induced by TGF-β or LPS and subsequently inhibited collagen production in lung fibroblasts. These data indicate that MGIIIE is a potent inhibitor for pulmonary fibrosis. In vitro and in vivo mechanistic studies have shown that MGIIIE significantly decreased expression of toll-like receptor 4 (TLR4) and its downstream signals of myeloid differentiation factor 88 (MyD88)/mitogen-activated protein kinase (MAPK), an inflammatory signal essential for extracellular matrix (ECM) deposition in pulmonary fibroblasts. Taken together, these results demonstrate that MGIIIE significantly prevents pulmonary fibrosis by inhibiting pulmonary inflammation and ECM deposition through regulating TLR4/MyD88-MAPK signaling. Our study suggests that MGIIIE may have therapeutic potential for treating pulmonary fibrosis in clinical settings.

RelA/p65 inhibition prevents tendon adhesion by modulating inflammation, cell proliferation, and apoptosis

Peritendinous tissue fibrosis which leads to poor tendon function is a worldwide clinical problem; however, its mechanism remains unclear. Transcription factor RelA/p65, an important subunit in the NF-κB complex, is known to have a critical role in many fibrotic diseases. Here, we show that RelA/p65 functions as a core fibrogenic regulator in tendon adhesion and that its inhibition exerts an anti-fibrogenic effect on peritendinous adhesion. We detected the upregulation of the NF-κB pathway in human tendon adhesion using a gene chip microarray assay and revealed the overexpression of p65 and extracellular matrix (ECM) proteins Collagen I, Collagen III, and α-smooth muscle actin (α-SMA) in human fibrotic tissues by immunohistochemistry and western blotting. We also found that in a rat model of tendon injury, p65 expression correlated with tendon adhesion, whereas its inhibition by small interfering (si)RNA prevented fibrous tissue formation and inflammatory reaction as evidenced by macroscopic, biomechanical, histological, immunohistochemical, and western blotting analyses. Furthermore, in cultured fibroblasts, p65-siRNA, p65-specific inhibitor, Helenalin and JSH23 suppressed cell proliferation and promoted apoptosis, whereas inhibiting the mRNA and protein expression of ECM components and cyclo-oxygenase-2, an inflammatory factor involved in tendon adhesion. Our findings indicate that p65 has a critical role in peritendinous tissue fibrosis and suggest that p65 knockdown may be a promising therapeutic approach to prevent tendon adhesion.

TNFAIP3 overexpression is an independent factor for poor survival in esophageal squamous cell carcinoma

Tumor necrosis factor α induced protein 3 (TNFAIP3) is a protein that is induced by TNF-mediated NF-κB activation and has a dual function in regulating NF-κB. TNFAIP3 is associated with inflammatory carcinogenesis in many cancer types. However, the clinical significance of TNFAIP3 expression and function in esophageal squamous cell carcinoma (ESCC) has not yet been reported. We examined 149 ESCC tissue specimens to determine the clinical significance of TNFAIP3 by immunohistochemistry. Western blot analyses were used to detect TNFAIP3 expression in TE-1, TE-8, TE-15 and KYSE-70 ESCC cells and in Het-1A, a non-cancerous esophageal cell line. TNFAIP3 protein knockdown was conducted using small-interfering RNA to investigate its impact on cell proliferation, migration and invasion. Significant correlations between TNFAIP3 expression and differentiation (P=0.04) among clinicopathological characteristics of ESCC patients were demonstrated, and high TNFAIP3 expression was associated with poor survival (P=0.02). Moreover, multivariate analysis result showed that high TNFAIP3 expression was an independent factor for poor survival (P=0.04). In vitro analysis showed high expression of TNFAIP3 protein in TE-15 cells and low expression in Het-1A cells. Furthermore, the proliferation, migration and invasion of TE-15 cells after TNFAIP3 suppression by siRNA were significantly reduced. These findings suggest that TNFAIP3 protein may be an independent prognostic marker for poor survival, and a promising target for ESCC therapy.

Effect of Renshen Pingfei Decoction, a traditional Chinese prescription, on IPF induced by Bleomycin in rats and regulation of TGF-β1/Smad3

AIM OF THE STUDY

Idiopathic pulmonary fibrosis (IPF), one of the clinical common diseases, shares similar pathogenesis with ancient disease "Feibi" in Chinese medicine, Renshen pingfei decoction (RPFS), a classical prescription, was commonly used in treating Feibi. In the current study, the protective role of RPFS in rats model of IPF and the mechanism via regulation of TGF-β1/Smad3, were evaluated and explored.

METHODS

The chemicals of RPFS were analyzed by UPLC-QTOF-MS. Under the optimized chromatographic and MS condition, the major components in RPFS were well separated and detected. An IPF model was established in rats which were induced with Bleomycin (BLM). After treated with corresponding medicine for 7 days, 14 days, 21 days and 28 days respectively, lung function of rats were measured; peripheral blood and bronchoalveolar lavage fluid (BALF) were assessed; histopathological changes and homogenate of lung tissue were detected; TGF-β1 and Smad3 mRNA and protein expressions in lung tissue were examined as well.

RESULTS

43 signal peaks of chemical components in RPFS were identified by UPLC-QTOF-MS method. Compared with model group, RPFS group exerted significant effects on IPF model rats in improving lung function and decreasing HYP content of lung tissue (P<0.01), reducing the level of TGF-β1 and NFκB in BALF (P<0.05), decreasing SOD and MDA level in serum (P<0.01), as well as down-regulating TGF-β1 and Smad3 mRNA and protein expressions of lung tissue (P<0.01).

CONCLUSION

RPFS could reduce the lung injury and fibrosis degree and improve lung function of IPF model rats. The protective role might mediated by down-regulating TGF-β1/Smad3 signaling pathway.

The Overexpression of TGF-β and CCN2 in Intrauterine Adhesions Involves the NF-κB Signaling Pathway

Intrauterine adhesions (IUA) are a significant cause of menstrual disturbance and infertility, but their pathogenesis still remains unclear. Here, we investigated the expression of TGF-β and CCN2 in IUA endometrial tissue by immunohistochemistry, western blotting and qRT-PCR assays, and found the expression of TGF-β and CCN2 in the endometrial tissue of IUA was significantly increased compared to normal endometrium and uterine septum (P<0.01), suggesting that TGF-β and CCN2 may play an important role in the formation of IUA. Moreover, the activity of the NF-κB signaling pathway in endometrial tissue of IUA was also significantly enhanced compared to normal endometrial and uterine septum (P<0.01) and positively correlated with the expression of TGF-β and CCN2, which suggested that TGF-β and CCN2 expression may be involved in the NF-κB signaling pathway. Blocking the NF-κB signaling pathway using SN50 resulted in the reduced expression of TGF-β in RL95-2 cells, which confirmed the association of the NF-κB signaling pathway and TGF-β in endometrial cells. Additionally, the expression of TGF-β and CCN2 was associated with IUA recurrence, which provides a potential prognostic indictor for IUA. Together, these results demonstrated that TGF-β and CCN2 play an important role in IUA formation, whose mechanism was associated with the activation of the NF-κB signaling pathway.

The IκB kinase inhibitor ACHP strongly attenuates TGFβ1-induced myofibroblast formation and collagen synthesis

Excessive accumulation of a collagen‐rich extracellular matrix (ECM) by myofibroblasts is a characteristic feature of fibrosis, a pathological state leading to serious organ dysfunction. Transforming growth factor beta1 (TGFβ1) is a strong inducer of myofibroblast formation and subsequent collagen production. Currently, there are no remedies for the treatment of fibrosis. Activation of the nuclear factor kappa B (NF‐κB) pathway by phosphorylating IκB with the enzyme IκB kinase (IKK) plays a major role in the induction of fibrosis. ACHP {2‐Amino‐6‐[2‐(cyclopropylmethoxy)‐6‐hydroxyphenyl]‐4‐(4‐piperidinyl)‐3 pyridinecarbonitrile}, a selective inhibitor of IKK, prohibits the activation of the NF‐κB pathway. It is not known whether ACHP has potential anti‐fibrotic properties. Using adult human dermal and lung fibroblasts we have investigated whether ACHP has the ability to inhibit the TGFβ1‐induced transition of fibroblasts into myofibroblasts and its excessive synthesis of ECM. The presence of ACHP strongly suppressed the induction of the myofibroblast markers alpha‐smooth muscle actin (αSMA) and SM22α, as well as the deposition of the ECM components collagen type I and fibronectin. Furthermore, post‐treatment with ACHP partly reversed the expression of αSMA and collagen type I production. Finally, ACHP suppressed the expression of the three collagen‐modifying enzymes lysyl hydroxylase (PLOD1,PLOD2 and PLOD3) in dermal fibroblasts, but did not do so in lung fibroblasts. We conclude that the IKK inhibitor ACHP has potent antifibrotic properties, and that the NF‐κB pathway plays an important role in myofibroblast biology.