Periostin promotes hepatic fibrosis in mice by modulating hepatic stellate cell activation via αv integrin interaction

Periostin Induces Epithelial-Mesenchymal Transition via p38-MAPK Pathway in Human Renal Tubular Cells by High Glucose

BACKGROUND

Periostin mediates inflammation and fibrosis by regulating extracellular matrix adhesion, migration, and differentiation in multiple organ diseases. Studies have shown periostin mainly located in the dilated mesangium, tubulointerstitial and fibrotic regions of the diabetic kidney disease, which was negatively correlated with renal function. However, the underlying mechanism remains poorly explored.

METHODS

The expression of periostin in HK-2 cells was investigated under high glucose and high concentration of TGF-β1. The signaling pathway of periostin involved in epithelial-mesenchymal transdifferentiation of HK-2 cells was also validated. The expression of periostin were investigated by RT-PCR, western blot analysis and immunofluorescence assays with different concentrations of glucose and TGF-β1. The expression of E-Cad, α-SMA and p38 proteins were also detected. The effects of periostin, E-Cad, and α-SMA in high glucose were investigated by p38 inhibitors. To demonstrate the interaction among periostin, p38 and EMT markers, periostin under high glucose and high TGF-β1 was knocked down, resulting p38 and phosphorylated p38 was evaluated.

RESULTS

The combined of high glucose (HG, 22 mmol/L) and high TGF-β1 (10 ng/mL) upregulated the expression of periostin obviously, stimulating the expression of α-SMA and p38 while inhibiting the expression of E-Cad. p38 inhibitors reduced the expression of periostin and α-SMA while promoted E-Cad protein expression in HK-2 cells under HG conditions. Additionally, p38-MAPK signal pathway was involved in epithelial-mesenchymal transition of human renal tubules in high glucose environment. Significant, knockdown periostin expression effectively inhibited the expression of p38 and phosphorylated p38 under the combination of HG and high TGF-β1, verifying the interaction of periostin with the p38-MAPK signaling pathway.

CONCLUSION

Periostin, a downstream factor of TGF-β1, is positively regulated by TGF-β1 under HG condition, affecting the epithelial-interstitial differentiation of HK-2 cells via p38-MAPK signaling pathway. Therefore, periostin may serve as a biomarker of renal fibrosis in diabetic kidney disease.

Pregnane X receptor inhibits the transdifferentiation of hepatic stellate cells by down-regulating periostin expression

Pregnane X receptor (PXR) is a xenobiotic-sensing nuclear receptor that plays a key role in drug metabolism. Recently, PXR was found to attenuate the development of liver cancer by suppressing epithelial-mesenchymal transition (EMT) in liver cancer cells in a mouse model of two-stage chemical carcinogenesis. To elucidate the role of PXR in the EMT of liver cancer cells, we focused on its role in hepatic stellate cells (HSCs), which are components of the tumor microenvironment in hepatocellular carcinoma (HCC). Human HSC-derived LX-2 cells stably expressed destabilization domain (DD)-fused human PXR (hPXR-LX2 cells). Human HCC-derived HepG2 cells were transfected with the EMT marker VIM promoter-regulated reporter plasmid and co-cultured with hPXR-LX2 cells or treated with hPXR-LX2-derived conditioned medium (CM). Co-culture or CM treatment increased reporter activity in HepG2 cells. This induction was attenuated upon PXR activation in hPXR-LX2 cells by treatment with the DD-stabilizing chemical Shield-1 and the human PXR ligand rifampicin. PXR activation in hPXR-LX2 cells exhibited inhibition of TGF-β1-induced transdifferentiation, supported by observations of morphological changes and protein or mRNA levels of the transdifferentiation markers COL1A1 and FN1. PXR activation in hPXR-LX2 cells also attenuated the mRNA levels of the key transdifferentiation factor, POSTN. Treatment of hPXR-LX2 cells with recombinant POSTN restored the PXR-mediated suppression of transdifferentiation. Reporter assays with the POSTN promoter showed that PXR inhibited the NF-κB-mediated transcription of POSTN. Consequently, PXR activation in HSCs is expected to inhibit transdifferentiation by down-regulating POSTN expression, thereby suppressing EMT of liver cancer cells.

Antisense oligonucleotide is a promising intervention for liver diseases

As the body's critical metabolic organ, the liver plays an essential role in maintaining proper body homeostasis. However, as people's living standards have improved and the number of unhealthy lifestyles has increased, the liver has become overburdened. These have made liver disease one of the leading causes of death worldwide. Under the influence of adverse factors, liver disease progresses from simple steatosis to hepatitis, to liver fibrosis, and finally to cirrhosis and cancer, followed by increased mortality. Until now, there has been a lack of accepted effective treatments for liver disease. Based on current research, antisense oligonucleotide (ASO), as an alternative intervention for liver diseases, is expected to be an effective treatment due to its high efficiency, low toxicity, low dosage, strong specificity, and additional positive characteristics. In this review, we will first introduce the design, modification, delivery, and the mechanisms of ASO, and then summarize the application of ASO in liver disease treatment, including in non-alcoholic fatty liver disease (NAFLD), hepatitis, liver fibrosis, and liver cancer. Finally, we discuss challenges and perspectives on the transfer of ASO drugs into clinical use. This review provides a current and comprehensive understanding of the integrative and systematic functions of ASO for its use in liver disease.

Periostin contributes to the adventitial remodeling of atherosclerosis by activating adventitial fibroblasts

Background and aims

Adventitial remodeling is an important pathological process of atherosclerosis, but cues implicated in adventitial remodeling are far from fully understood. Periostin (POSTN), a matricellular protein, has been demonstrated to have multiple roles in cardiovascular diseases. The aim of the study was to explore the function of POSTN in adventitial remodeling during atherosclerosis.

Methods

An atherosclerosis model was constructed based on ApoE-/- mice fed a high-fat and high-cholesterol diet. The expression of POSTN in the adventitia of mouse atherosclerotic vascular specimens was detected by immunohistochemical staining. The roles of POSTN in regulating adventitial fibroblast activation were assessed by cell contractility and activation marker α-smooth muscle actin (α-SMA) expression evaluation in adventitial fibroblasts overexpressing POSTN. In addition, we performed quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting to examine the expression of the proinflammatory chemokines transforming growth factor-β1 (TGF-β1) and monocyte chemotactic protein 1 (MCP1), as well as some extracellular matrix (ECM)-related proteins, in POSTN-overexpressing adventitial fibroblasts. Finally, the integrin-related signaling pathway was detected upon POSTN overexpression in adventitial fibroblasts.

Results

POSTN was highly expressed in the adventitia of atherosclerotic aortae in the mouse atherosclerosis model and promoted the activation and contraction of adventitial fibroblasts. Meanwhile, POSTN also induced adventitial fibroblasts to express TGF-β1, monocyte chemotactic protein-1 (MCP1), and ECM-related proteins and activated the phosphorylation of focal adhesion kinase (FAK) and Src.

Conclusions

Our results revealed that POSTN is elevated in adventitia during atherosclerosis and contributes to the adventitial remodeling of atherosclerosis by activating adventitial fibroblasts.

Periostin: An Emerging Molecule With a Potential Role in Spinal Degenerative Diseases

Periostin, an extracellular matrix protein, is widely expressed in a variety of tissues and cells. It has many biological functions and is related to many diseases: for example, it promotes cell proliferation and differentiation in osteoblasts, which are closely related to osteoporosis, and mediates cell senescence and apoptosis in chondrocytes, which are involved in osteoarthritis. Furthermore, it also plays an important role in mediating inflammation and reconstruction during bronchial asthma, as well as in promoting bone development, reconstruction, repair, and strength. Therefore, periostin has been explored as a potential biomarker for various diseases. Recently, periostin has also been found to be expressed in intervertebral disc cells as a component of the intervertebral extracellular matrix, and to play a crucial role in the maintenance and degeneration of intervertebral discs. This article reviews the biological role of periostin in bone marrow-derived mesenchymal stem cells, osteoblasts, osteoclasts, chondrocytes, and annulus fibrosus and nucleus pulposus cells, which are closely related to spinal degenerative diseases. The study of its pathophysiological effects is of great significance for the diagnosis and treatment of spinal degeneration, although additional studies are needed.

Fibrotic Scar After Spinal Cord Injury: Crosstalk With Other Cells, Cellular Origin, Function, and Mechanism

The failure of axonal regeneration after spinal cord injury (SCI) results in permanent loss of sensorimotor function. The persistent presence of scar tissue, mainly fibrotic scar and astrocytic scar, is a critical cause of axonal regeneration failure and is widely accepted as a treatment target for SCI. Astrocytic scar has been widely investigated, while fibrotic scar has received less attention. Here, we review recent advances in fibrotic scar formation and its crosstalk with other main cellular components in the injured core after SCI, as well as its cellular origin, function, and mechanism. This study is expected to provide an important basis and novel insights into fibrotic scar as a treatment target for SCI.

Tengdan Capsule Prevents Hypertensive Kidney Damage in SHR by Inhibiting Periostin-Mediated Renal Fibrosis

BACKGROUND: Hypertension-induced renal damage is a serious and complex condition that has not been effectively treated by conventional blood pressure-lowering drugs. Tengdan capsule (TDC) is a China FDA-approved compound herbal medicine for treating hypertension; however, its chemical basis and pharmacological efficacy have not been fully investigated in a preclinical setting.

METHODS: High-performance liquid chromatography (HPLC) was used to identify and quantify the major chemical components of TDC extracted from ultrapure water. Adult spontaneously hypertensive rats (SHR) and age/sex-matched Wistar Kyoto normotensive rats (WKY) were both treated with TDC, losartan, or saline for one month, and their blood pressure (BP) was monitored at the same time by tail-cuff BP system. Biochemical indexes such as urine creatinine (CRE) and blood urea nitrogen (BUN) were determined. Kidney tissue sections were examined with (H&E), and Masson staining to evaluate the pathological effect of TDC on SHR’s kidneys. After TDC treatment, the differentially expressed proteins in the kidneys of SHR were identified by the TMT-based quantitative proteomics analysis, which may provide the targets and possible mechanisms of TDC action. In addition, Western blot analysis, RT-qPCR, and ELISA assays were carried out to further verify the proteomics findings. Finally, two different models involving in vitro renal injuries were established using human kidney HEK293 cells; and the molecular mechanism of TDC kidney protection was demonstrated.

RESULTS: Seven chemical compounds, namely Notoginsenoside R1, Ginsenoside RG1, Ginsenoside Re, Ginsenoside Rb1, Sodium Danshensu, Protocatechualdehyde, and Salvianolic acid B, were identified and quantified from the water-soluble extracts of TDC by HPLC. In vivo study using rats showed that TDC effectively reduced BP, BUN, and CRE levels and attenuated renal fibrosis in SHR, and ameliorated damage to the kidneys. Proteomics and subsequent bioinformatics analyses indicated that periostin-mediated inflammatory response and TGFβ/Smad signaling pathway proteins were closely related to the therapeutic effect of TDC in rat kidneys. Western blot analysis and RT-qPCR showed that TDC markedly downregulated the mRNA and protein expression of periostin in renal tissues compared to the untreated SHR. In addition, TGF-β and COL1A1 mRNA levels also decreased in SHR renal tissues following TDC treatment. In vitro studies showed that low to medium doses of TDC down-regulated the expression of periostin in the injury model of HEK293 cell. In addition, medium to high doses of TDC significantly inhibited collagen deposition in TGFβ1-induced HEK293 cell fibrosis.

CONCLUSIONS: Major components from the compound herbal medicine Tengdan Capsule are identified and quantified. TDC effectively lowers blood pressure and protects against renal damage caused by hypertension in SHR. Mechanistically, TDC blocks periostin by regulating the TGF-β/Smad signaling pathway in the kidney, both in vivo and in vitro. Preventing periostin-mediated renal fibrosis and inflammation might be a promising strategy for treating a hypertensive renal injury.

A single injection of periostin decreases cardiac voltage-gated Na+ channel in rat ventricles

Changes in electrophysiological properties, such as ion channel expression and activity, are closely related to arrhythmogenesis during heart failure (HF). However, a causative factor for the electrical remodeling in HF has not been determined. Periostin (POSTN), a matricellular protein, is increased in heart tissues of patients with HF. In the present study, we investigated whether a single injection of POSTN affects the electrophysiological properties in rat ventricles. After male Wistar rats were intravenously injected with recombinant rat POSTN (64 µg/kg, 24 hr), electrocardiogram (ECG) was recorded. Whole-cell patch clamp was performed to measure action potential (AP) and Na⁺ current (I_Na) in isolated ventricular myocytes. Protein expression of cardiac voltage-gated Na⁺ channel (Na_V1.5) in isolated ventricles was examined by Western blotting. In ECG, POSTN-injection significantly increased RS height. POSTN-injection significantly delayed time to peak in AP and decreased I_Na in the isolated ventricular myocytes. POSTN-injection decreased Na_V1.5 expression in the isolated ventricles. It was confirmed that POSTN (1 µg/ml, 24 hr) decreased I_Na and Na_V1.5 protein expression in neonatal rat ventricular myocytes. This study for the first time demonstrated that a single injection of POSTN in rats decreased I_Na by suppressing Na_V1.5 expression in the ventricular myocytes, which was accompanied by a prolongation of time to peak in AP and an increase of RS height in ECG.

Periostin antisense oligonucleotide prevents hepatic steatosis and fibrosis in a mouse model of non-alcoholic steatohepatitis

BACKGROUND AND AIM

Non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis, inflammation, and hepatocellular injury with varying degrees of fibrosis. There are currently no established treatment approaches for NASH other than lifestyle interventions. Periostin, a matricellular protein required for tissue remodeling and fibrosis, plays an important role in hepatic steatosis and fibrosis and could be a potential target for NASH treatment. Advances in molecular biology and biochemical engineering have led to the development of antisense oligonucleotides (ASOs) that can inhibit target genes with no significant toxic effects. Herein, we investigated the therapeutic effects of periostin-targeting ASO (PNASO) in NASH.

METHODS

C57BL/6J mice were fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) to induce NASH with or without intraperitoneal injection of mouse PNASO. To explore the role of periostin in hepatocellular steatosis, Hc3716 cells, an immortalized human hepatocyte line, were treated with recombinant periostin in vitro.

RESULTS

The induced periostin expression in the liver of CDAHFD-fed mice was significantly suppressed by PNASO. The deletion of hepatic periostin by PNASO significantly ameliorated hepatic steatosis while restoring the expression levels of peroxisome proliferator-activated receptor-alpha (PPAR-α) and its target genes. PNASO also inhibited hepatic fibrosis, reflected by the reduction of alpha-smooth muscle actin, collagen type I, and other fibrotic markers. In vitro experiments demonstrated that treatment with recombinant periostin increased cellular lipid accumulation in Hc3716 cells accompanied with the downregulation of PPAR-α.

CONCLUSIONS

Periostin-targeting ASO is a potential therapeutic approach for the efficient treatment of hepatic steatosis and fibrosis in NASH.

Periostin Circulating Levels and Genetic Variants in Patients with Non-Alcoholic Fatty Liver Disease

Circulating periostin has been suggested as a possible biomarker in non-alcoholic fatty liver disease (NAFLD) in Asian studies. In the present study, we aimed to test its still controversial relevance in a Caucasian population. In patients with histologically-proven NAFLD (N. = 74; 10 with hepatocellular carcinoma, HCC) plasma periostin concentrations were analyzed. POSTN haplotype analysis was based on rs9603226, rs3829365, and rs1029728. Hepatitis C patients (N. = 81, 7 HCC) and healthy subjects (N. = 27) were used as controls. The median plasma periostin concentration was 11.6 ng/mL without differences amongst groups; it was not influenced by age, liver fibrosis or steatosis. However, possession of haplotype two (rs9603226 = G, rs3829365 = C, rs1028728 = A) was associated with lower circulating periostin compared to other haplotypes. Moreover, periostin was higher in HCC patients. At multivariate analysis, HCC remained the only predictor of high periostin. In conclusion, plasma periostin concentrations in Caucasians NAFLD patients are not influenced by the degree of liver disease, but are significantly higher in HCC. Genetically-determined differences may account for some of the variability. These data suggest extreme caution in predicting a possible future role of periostin antagonists as a rational therapeutic alternative for NAFLD, but show a potential periostin role in the management of NAFLD-associated HCC.

Immunomodulatory Role of the Extracellular Matrix Within the Liver Disease Microenvironment

Chronic liver disease when accompanied by underlying fibrosis, is characterized by an accumulation of extracellular matrix (ECM) proteins and chronic inflammation. Although traditionally considered as a passive and largely architectural structure, the ECM is now being recognized as a source of potent damage-associated molecular pattern (DAMP)s with immune-active peptides and domains. In parallel, the ECM anchors a range of cytokines, chemokines and growth factors, all of which are capable of modulating immune responses. A growing body of evidence shows that ECM proteins themselves are capable of modulating immunity either directly via ligation with immune cell receptors including integrins and TLRs, or indirectly through release of immunoactive molecules such as cytokines which are stored within the ECM structure. Notably, ECM deposition and remodeling during injury and fibrosis can result in release or formation of ECM-DAMPs within the tissue, which can promote local inflammatory immune response and chemotactic immune cell recruitment and inflammation. It is well described that the ECM and immune response are interlinked and mutually participate in driving fibrosis, although their precise interactions in the context of chronic liver disease are poorly understood. This review aims to describe the known pro-/anti-inflammatory and fibrogenic properties of ECM proteins and DAMPs, with particular reference to the immunomodulatory properties of the ECM in the context of chronic liver disease. Finally, we discuss the importance of developing novel biotechnological platforms based on decellularized ECM-scaffolds, which provide opportunities to directly explore liver ECM-immune cell interactions in greater detail.

Dynein-mediated nuclear translocation of yes-associated protein through microtubule acetylation controls fibroblast activation

Myofibroblasts are the major cell type that is responsible for increase in the mechanical stiffness in fibrotic tissues. It has well documented that the TGF-β/Smad axis is required for myofibroblast differentiation under the rigid substrate condition. However, the mechanism driving myofibroblast differentiation in soft substrates remains unknown. In this research, we demonstrated that interaction of yes-associated protein (YAP) and acetylated microtubule via dynein, a microtubule motor protein drives nuclear localization of YAP in the soft matrix, which in turn increased TGF-β1-induced transcriptional activity of Smad for myofibroblast differentiation. Pharmacological and genetical disruption of dynein impaired the nuclear translocation of YAP and decreased the TGF-β1-induced Smad activity even though phosphorylation and nuclear localization of Smad occurred normally in α-tubulin acetyltransferase 1 (α-TAT1) knockout cell. Moreover, microtubule acetylation prominently appeared in the fibroblast-like cells nearby the blood vessel in the fibrotic liver induced by CCl4 administration, which was conversely decreased by TGF-β receptor inhibitor. As a result, quantitative inhibition of microtubule acetylation may be suggested as a new target for overcoming fibrotic diseases.

SPOCK1 overexpression induced by platelet-derived growth factor-BB promotes hepatic stellate cell activation and liver fibrosis through the integrin α5β1/PI3K/Akt signaling pathway

Sparc/osteonectin, cwcv, and kazal-like domain proteoglycan 1 (SPOCK1) is a matricellular protein which regulates cell proliferation, invasion, and survival but the function of SPOCK1 in liver fibrosis is obscure. In this study, we found that SPOCK1 expression increased significantly in fibrotic liver tissues and activated primary rat hepatic stellate cells (R-HSCs). SPOCK1 co-localized with α-smooth muscle actin (α-SMA) in the cytoplasm. Mechanistically, we found platelet-derived growth factor-BB (PDGF-BB) induced SPOCK1 expression by activating the PI3K/Akt/forkhead box M1 (FoxM1) signaling pathway. Intracellular SPOCK1 downregulation decreased the HSC activation, proliferation, and migration induced by PDGF-BB. Furthermore, intracellular SPOCK1 overexpression or recombinant SPOCK1 treatment promoted HSC activation, proliferation, and migration by activating the PI3K/Akt signaling pathway. Co-immunoprecipitation, double immunofluorescence staining indicated that SPOCK1 interacted with integrin α5β1, and neutralization of integrin α5β1 significantly reduced the role of recombinant SPOCK1 in HSCs. In vivo HSC-specific SPOCK1 knockdown following lentivirus administration dramatically ameliorated thioacetamide (TAA)-induced collagen deposition in rat livers. Collectively, our study indicates that SPOCK1 is crucial for hepatic fibrosis and it might be a promising therapeutic target.

Blockade of periostin-dependent migration and adhesion by curcumol via inhibition of nuclear factor kappa B signaling in hepatic stellate cells

OBJECTIVES

Curcumol, a guaiane-type sesquiterpenoid hemiketal extracted from the herb Rhizoma Curcumae, exhibits multiple-pharmacological activities. We previously reported that curcumol ameliorated hepatic fibrosis by inhibiting hepatic stellate cell (HSC) activation. In this study, we aimed to investigate the effect of curcumol on HSC migration and adhesion, and reveal its regulation mechanisms.

MATERIALS AND METHODS

Cellular viability was determined by Cell Counting Kit-8. Cell migration was detected by boyden chamber and cell scratch experiment. Recombinant human periostin (rh POSTN) and adeno-associated viral (AAV)-GFP-periostin were used to achieve POSTN overexpression in vitro and in vivo, respectively. Nuclear factor kappa B (NF-κB)-p65 overexpression was achieved by using plasmid. ELISA was conducted to detect POSTN level. Immunohistochemistry, qRT-PCR, Western blotting, and immunofluorescence were performed to assess associated factor expression.

RESULTS

Curcumol suppressed HSC migration and adhesion, and reduced the secretion and expression of POSTN. By gain of function POSTN in HSCs, using rh POSTN, we found that the inhibition of HSC migration and adhesion by curcumol depended on the decrease of POSTN. Besides, curcumol protection against chronic CCl₄-caused hepatic fibrosis could be impaired by POSTN overexpression. Moreover, we showed that curcumol repressed NF-κB signaling and the production of pro-inflammatory factor. Importantly, curcumol down-regulation of POSTN was rescued by knock-in of NF-κB, as well as the inhibition of HSC migration and adhesion.

CONCLUSION

These findings reveal the molecular mechanism of curcumol-reduced HSC migration and adhesion, by which points to the possibility of using curcumol based on NF-κB dependent POSTN for the treatment of fibrogenesis.

Novel Targets for Therapy of Renal Fibrosis

Renal fibrosis is an important component of chronic kidney disease, an incurable pathology with increasing prevalence worldwide. With a lack of available therapeutic options, end-stage renal disease is currently treated with renal replacement therapy through dialysis or transplantation. In recent years, many efforts have been made to identify novel targets for therapy of renal diseases, with special focus on the characterization of unknown mediators and pathways participating in renal fibrosis development. Using experimental models of renal disease and patient biopsies, we identified four novel mediators of renal fibrosis with potential to constitute future therapeutic targets against kidney disease: discoidin domain receptor 1, periostin, connexin 43, and cannabinoid receptor 1. The four candidates were highly upregulated in different models of renal disease and were localized at the sites of injury. Subsequent studies showed that they are centrally involved in the underlying mechanisms of renal fibrosis progression. Interestingly, inhibition of either of these proteins by different strategies, including gene deletion, antisense administration, or specific blockers, delayed the progression of renal disease and preserved renal structure and function, even when the inhibition started after initiation of the disease. This review will summarize the current findings on these candidates emphasizing on their potential to constitute future targets of therapy.

Periostin in chronic liver diseases: Current research and future perspectives

The liver is importantly metabolic and detoxifying organ in the body. When various pathogenic factors affect the liver, the normal physiological and biochemical functions are weakened, resulting in liver diseases. Liver fibrosis is a common pathological process of chronic liver disease. During hepatic fibrosis the changes in the components of the extracellular matrix (ECM) provide an environment that facilitates tissue remodeling. Among these ECM components, periostin, a glycoprotein that is predominantly secreted by osteoblasts and their precursors, playing an important role in bone formation, has attracted great attention. Periostin not only involves in bone metabolism, but also functions in modulating the cell fate determination, proliferation, inflammatory responses, even tumorigenesis of many other tissues and organs including liver. In different categories of liver disease patients, the serum and liver tissue levels of periostin were closely related to the decline of liver function, and the pathological stage. Numerous animal studies and experiments in vitro subsequently demonstrated that the abnormal expression of periostin resulted in metabolic disorders, liver inflammation, fibrosis and even tumorigenesis. Here we review the current progress on the role of periostin in pathologic pathways of liver system to explore whether periostin is a potential therapeutic target for the treatment of different liver diseases.

Estimation of Periostin and Tumour Necrosis Factor-α in Type II Diabetics with Chronic Periodontitis: A case-control study

Background:

Periostin, a matricellular protein, is downregulated in chronic inflammatory periodontal disease and is negatively modulated by tumor necrosis factor-α (TNF-α) in human periodontal fibroblast cell culture. The study aimed to estimate the gingival crevicular fluid (GCF) levels of periostin and TNF-α and to discern their relationship in chronic periodontitis (CP) individuals with and without Type II diabetes mellitus (DM).

Materials and Methods:

A total of 60 participants were divided into three groups, with 20 in each group. Group I – systemically and periodontally healthy, Group II – generalized CP, and Group III – generalized CP with Type II DM. Plaque index, gingival index, sulcular bleeding index, probing depth, and clinical attachment level were recorded. GCF periostin and TNF-α were quantified using the enzyme-linked immunosorbent assay.

Results:

Intergroup comparison was performed using the one-way ANOVA and Kruskal–Wallis. The relationship between the variables was analyzed using the Pearson's and Kendall's Tau correlation. The GCF periostin levels in Groups I, II, and III was 27.52 ± 2.39 ng/mL, 20.18 ± 1.42 ng/mL, and 16.77 ± 3.29 ng/mL, respectively. The GCF TNF-α levels in Groups I, II, and III was 92.41 ± 19.30 ng/L, 118.53 ± 21.93 ng/L, and 147.67 ± 16.35 ng/L, respectively. Periostin decreased, and TNF-α increased in periodontal disease; moreover, periostin level correlated negatively with all the site-specific clinical parameters whereas TNF-α positively correlated (P < 0.001).

Conclusions:

TNF-α strongly and negatively downregulates periostin in a chronically inflamed locale leading to compromised integrity of the periodontium.

A humanized mouse model to study asthmatic airway inflammation via the human IL-33/IL-13 axis

Asthma is one of the most common immunological diseases and is characterized by airway hyperresponsiveness (AHR), mucus overproduction, and airway eosinophilia. Although mouse models have provided insight into the mechanisms by which type-2 cytokines induce asthmatic airway inflammation, differences between the rodent and human immune systems hamper efforts to improve understanding of human allergic diseases. In this study, we aim to establish a preclinical animal model of asthmatic airway inflammation using humanized IL-3/GM-CSF or IL-3/GM-CSF/IL-5 Tg NOD/Shi-scid-IL2rγnull (NOG) mice and investigate the roles of human type-2 immune responses in the asthmatic mice. Several important characteristics of asthma - such as AHR, goblet cell hyperplasia, T cell infiltration, IL-13 production, and periostin secretion - were induced in IL-3/GM-CSF Tg mice by intratracheally administered human IL-33. In addition to these characteristics, human eosinophilic inflammation was observed in IL-3/GM-CSF/IL-5 Tg mice. The asthmatic mechanisms of the humanized mice were driven by activation of human Th2 and mast cells by IL-33 stimulation. Furthermore, treatment of the humanized mice with an anti-human IL-13 antibody significantly suppressed these characteristics. Therefore, the humanized mice may enhance our understanding of the pathophysiology of allergic disorders and facilitate the preclinical development of new therapeutics for IL-33-mediated type-2 inflammation in asthma.

Aptamers: Uptake mechanisms and intracellular applications

The structural flexibility and small size of aptamers enable precise recognition of cellular elements for imaging and therapeutic applications. The process by which aptamers are taken into cells depends on their targets but is typically clathrin-mediated endocytosis or macropinocytosis. After internalization, most aptamers are transported to endosomes, lysosomes, endoplasmic reticulum, Golgi apparatus, and occasionally mitochondria and autophagosomes. Intracellular aptamers, or “intramers,” have versatile functions ranging from intracellular RNA imaging, gene regulation, and therapeutics to allosteric modulation, which we discuss in this review. Immune responses to therapeutic aptamers and the effects of G-quadruplex structure on aptamer function are also discussed.

Liver fibrosis: Direct antifibrotic agents and targeted therapies

Liver fibrosis and in particular cirrhosis are the major causes of morbidity and mortality of patients with chronic liver disease. Their prevention or reversal have become major endpoints in clinical trials with novel liver specific drugs. Remarkable progress has been made with therapies that efficiently address the cause of the underlying liver disease, as in chronic hepatitis B and C. Highly effective antiviral therapy can prevent progression or even induce reversal in the majority of patients, but such treatment remains elusive for the majority of liver patients with advanced alcoholic or nonalcoholic steatohepatitis, genetic or autoimmune liver diseases. Moreover, drugs that would speed up fibrosis reversal are needed for patients with cirrhosis, since even with effective causal therapy reversal is slow or the disease may further progress. Therefore, highly efficient and specific antifibrotic agents are needed that can address advanced fibrosis, i.e., the detrimental downstream result of all chronic liver diseases. This review discusses targeted antifibrotic therapies that address molecules and mechanisms that are central to fibrogenesis or fibrolysis, including strategies that allow targeting of activated hepatic stellate cells and myofibroblasts and other fibrogenic effector cells. Focus is on collagen synthesis, integrins and cells and mechanisms specific including specific downregulation of TGFbeta signaling, major extracellular matrix (ECM) components, ECM-crosslinking, and ECM-receptors such as integrins and discoidin domain receptors, ECM-crosslinking and methods for targeted delivery of small interfering RNA, antisense oligonucleotides and small molecules to increase potency and reduce side effects. With an increased understanding of the biology of the ECM and liver fibrosis and an improved preclinical validation, the translation of these approaches to the clinic is currently ongoing. Application to patients with liver fibrosis and a personalized treatment is tightly linked to the development of noninvasive biomarkers of fibrosis, fibrogenesis and fibrolysis.

Pro-fibrotic phenotype of human skin fibroblasts induced by periostin via modulating TGF-β signaling

BACKGROUND

Periostin is a matricellular protein that belongs to a class of extracellular matrix (ECM)-related molecules defined by their ability to modulate cell-matrix interactions. We previously reported an elevated level of circulating periostin in patients with systemic sclerosis (SSc) and its association with the severity of skin sclerosis.

OBJECTIVE

To examine the role of periostin in transforming growth factor (TGF)-β signaling involved in fibrosis.

METHODS

Levels of periostin were examined in skin and lung fibroblasts obtained from SSc patients. Levels of ECM proteins and pro-fibrotic factors were evaluated in periostin-expressing human skin fibroblasts in the presence or absence of TGF-β. Effects of periostin on the Smad proteins were also evaluated following stimulation with TGF-β by immunoblotting, immunofluorescence staining, and RNA interference.

RESULTS

Periostin was strongly expressed in skin and lung fibroblasts from SSc patients. Although recombinant periostin alone did not affect ECM protein levels, TGF-β and recombinant periostin treatment or periostin overexpression in skin fibroblasts significantly enhanced the production of ECM proteins. Overexpression of periostin in the presence of TGF-β also augmented expressions of α-smooth muscle actin and early growth response-1 but decreased the level and activity of matrix metalloproteinase 1. Interestingly, the level of Smad 7, a TGF-β-inducible inhibitor of TGF-β signaling, was reduced in periostin-expressing fibroblasts but increased in periostin-silenced fibroblasts. In addition, Smad 7 reduction induced by periostin was partially inhibited in integrin α_V-silenced fibroblasts.

CONCLUSION

Periostin contributes to fibrosis by enhancing TGF-β signaling via Smad 7 inhibition, which may lead to ECM deposition and periostin generation.

Constitutive overexpression of periostin delays wound healing in mouse skin

Periostin is a matricellular protein involved in development, maintenance, and regulation of tissues and organs via by binding to cell surface integrin receptors. Pathologically, periostin plays an important role in the process of wound healing: as a deficiency of the Postn gene delays wound closure and periostin is consistently up-regulated in response to injury and skin diseases. However, the functional role of elevated periostin in the process of wound healing has not been tested. In this study, we generated Postn-transgenic mice under the control of the CAG promoter/enhancer to investigate the effects of constitutive overexpression of full length periostin during its pathophysiological roles. Transgenic mice showed significant overexpression of periostin in skin, lung, and heart, but no morphological changes were observed. However, when these transgenic mice were injured, periostin overexpression delayed the closure of excisional wounds. Expression of IL-1β and TNFα, pro-inflammatory cytokines important for wound healing, was significantly decreased in the transgenic mice, prior to delayed healing. Infiltration of neutrophils and macrophages, the main sources of IL-1β and TNFα, was also down-regulated in the transgenic wound sites. From these data, we conclude that enforced expression of periostin delays wound closure due to reduced infiltration of neutrophils and macrophages followed by down-regulation of IL-1β and TNFα expression. This suggests that regulated spatiotemporal expression of periostin is important for efficient wound healing and that constitutive periostin overexpression interrupts the normal process of wound closure.

Expression of CTGF/CCN2 in response to LPA is stimulated by fibrotic extracellular matrix via the integrin/FAK axis

Fibrosis is a common feature of several chronic diseases and is characterized by exacerbated accumulation of ECM. An understanding of the cellular and molecular mechanisms involved in the development of this condition is crucial for designing efficient treatments for those pathologies. Connective tissue growth factor (CTGF/CCN2) is a pleiotropic protein with strong profibrotic activity. In this report, we present experimental evidence showing that ECM stimulates the synthesis of CTGF in response to lysophosphatidic acid (LPA).The integrin/focal adhesion kinase (FAK) signaling pathway mediates this effect, since CTGF expression is abolished by the use of the Arg-Gly-Asp-Ser peptide and also by an inhibitor of FAK autophosphorylation at tyrosine 397. Cilengitide, a specific inhibitor of αv integrins, inhibits the expression of CTGF mediated by LPA or transforming growth factor β1. We show that ECM obtained from decellularized myofibroblast cultures or derived from activated fibroblasts from muscles of the Duchenne muscular dystrophy mouse model ( mdx) induces the expression of CTGF. This effect is dependent on FAK phosphorylation in response to its activation by integrin. We also found that the fibrotic ECM inhibits skeletal muscle differentiation. This novel regulatory mechanism of CTGF expression could be acting as a positive profibrotic feedback between the ECM and CTGF, revealing a novel concept in the control of fibrosis under chronic damage.

Periostin in kidney diseases

Chronic kidney disease is an incurable to date pathology, with renal replacement therapy through dialysis or transplantation being the only available option for end-stage patients. A deeper understanding of the molecular mechanisms governing the progression of kidney diseases will permit the identification of unknown mediators and potential novel markers or targets of therapy which promise more efficient diagnostic and therapeutic applications. Over the last years, periostin was established by several studies as a novel key player in the progression of renal disease. Periostin is de novo expressed focally by the injured kidney cells during the development of renal disease. In diverse cohorts of renal disease patients, the expression levels of periostin in the kidney and urine were highly correlated with the stage of the pathology and the decline of renal function. Subsequent studies in animal models demonstrated that periostin is centrally involved in mediating renal inflammation and fibrosis, contributing to the deterioration of renal structure and function. Genetic or pharmaco-genetic inhibition of periostin in animal models of renal disease was efficient in arresting the progression of the pathology. This review will summarize the recent advances on periostin in the field of kidney diseases and will discuss its utility of as a novel target of therapy for chronic kidney disease.

Periostin and its interacting proteins in the construction of extracellular architectures

Periostin is a matricellular protein that is composed of a multi-domain structure with an amino-terminal EMI domain, a tandem repeat of four FAS 1 domains, and a carboxyl-terminal domain. These distinct domains have been demonstrated to bind to many proteins including extracellular matrix proteins (Collagen type I and V, fibronectin, tenascin, and laminin), matricellular proteins (CCN3 and βig-h3), and enzymes that catalyze covalent crosslinking between extracellular matrix proteins (lysyl oxidase and BMP-1). Adjacent binding sites on periostin have been suggested to put the interacting proteins in close proximity, promoting intermolecular interactions between each protein, and leading to their assembly into extracellular architectures. These extracellular architectures determine the mechanochemical properties of connective tissues, in which periostin plays an important role in physiological homeostasis and disease progression. In this review, we introduce the proteins that interact with periostin, and discuss how the multi-domain structure of periostin functions as a scaffold for the assembly of interacting proteins, and how it underlies construction of highly sophisticated extracellular architectures.

Periostin promotes malignant potential by induction of epithelial-mesenchymal transition in intrahepatic cholangiocarcinoma

Periostin, a secreted matricellular protein, has been reported to induce epithelial‐mesenchymal transition (EMT), which increases motility and invasiveness in various epithelial cancer cells. Periostin is also overexpressed in intrahepatic cholangiocarcinoma (ICC) and suggested to be a biomarker for tumor progression and poor prognosis; however, its functional role in ICC is not fully understood. Here, we investigated whether periostin influences malignant potential through the induction of EMT in ICC. Analyses of surgical resected ICC specimens revealed that the gene expression of periostin was significantly higher in ICC tumors than in adjacent nontumor liver tissues and was closely correlated with the expression of mesenchymal markers, including N‐cadherin, vimentin, and fibronectin. However, the expression level of periostin varied in each case. Consistently, the expression of periostin in HuH28 (an undifferentiated ICC cell) was markedly higher than in HuCCT‐1 (a moderately differentiated ICC cell). In addition, high‐level secretion of periostin into culture media was observed in HuH28 but not in HuCCT‐1. To identify the biological significance of periostin in EMT, gene silencing of periostin by small interfering RNA was performed in HuH28 cells. Periostin knockdown in HuH28 cells significantly down‐regulated mesenchymal markers and up‐regulated epithelial markers, suggesting the reversal of EMT, namely mesenchymal‐epithelial transition. Along with these changes, cell proliferation was significantly suppressed by 52%. In addition, cell migration and invasion were significantly suppressed by 62% and 61%, respectively, with reduced gene expression of matrix metalloproteinase 2. Interestingly, chemosensitivity to gemcitabine was also significantly improved by periostin depletion. Conclusion: Periostin plays an important role in the regulation of malignant potential through EMT and is suggested to be a novel target for the treatment of ICC. (Hepatology Communications 2017;1:1099–1109)

Periostin promotes migration and invasion of renal cell carcinoma through the integrin/focal adhesion kinase/c-Jun N-terminal kinase pathway

Periostin (POSTN) is an extracellular matrix protein which is overexpressed in a variety of cancers and has been related to tumorigenesis of renal cell carcinoma. However, the involvement of POSTN in renal cell carcinoma migration, invasion, and their underlying mechanisms has not been established. In this study, renal cell carcinoma cell lines stably overexpressing POSTN were established using a lentiviral vector, and the effects of POSTN on renal cell carcinoma cell migration and invasion were investigated. POSTN overexpression increased the migration and invasion capabilities of renal cell carcinoma cell lines as well as activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. Integrin α_vβ₃ and α_vβ₅ antibodies inhibited POSTN overexpression or recombinant POSTN-induced focal adhesion kinase activation, cell migration, and invasion. Furthermore, lentivirus-mediated focal adhesion kinase knockdown and c-Jun N-terminal kinase inhibitor reduced POSTN-enhanced phosphorylation of c-Jun N-terminal kinase, matrix metalloproteinase-9 and matrix metalloproteinase-2 expressions, cell migration, and invasion. Our research thus indicates that POSTN promotes renal cell carcinoma cell migration and invasion through interaction with integrins α_vβ₃ and α_vβ₅ and subsequent activation of the focal adhesion kinase/c-Jun N-terminal kinase pathway. These results suggest that POSTN plays a critical role in renal cell carcinoma metastasis and may represent a potential target for novel therapeutic approaches against renal cell carcinoma.

Sclerostin's role in bone's adaptive response to mechanical loading

Mechanical loading is the primary functional determinant of bone mass and architecture, and osteocytes play a key role in translating mechanical signals into (re)modelling responses. Although the precise mechanisms remain unclear, Wnt signalling pathway components, and the anti-osteogenic canonical Wnt inhibitor Sost/sclerostin in particular, play an important role in regulating bone's adaptive response to loading. Increases in loading-engendered strains down-regulate osteocyte sclerostin expression, whereas reduced strains, as in disuse, are associated with increased sclerostin production and bone loss. However, while sclerostin up-regulation appears to be necessary for the loss of bone with disuse, the role of sclerostin in the osteogenic response to loading is more complex. While mice unable to down-regulate sclerostin do not gain bone with loading, Sost knockout mice have an enhanced osteogenic response to loading. The molecular mechanisms by which osteocytes sense and transduce loading-related stimuli into changes in sclerostin expression remain unclear but include several, potentially interlinked, signalling cascades involving periostin/integrin, prostaglandin, estrogen receptor, calcium/NO and Igf signalling. Deciphering the mechanisms by which changes in the mechanical environment regulate sclerostin production may lead to the development of therapeutic strategies that can reverse the skeletal structural deterioration characteristic of disuse and age-related osteoporosis and enhance bones' functional adaptation to loading. By enhancing the osteogenic potential of the context in which individual therapies such as sclerostin antibodies act it may become possible to both prevent and reverse the age-related skeletal structural deterioration characteristic of osteoporosis.

Periostin Promotes Scar Formation through the Interaction between Pericytes and Infiltrating Monocytes/Macrophages after Spinal Cord Injury

Scar formation is a prominent pathological feature of traumatic central nervous system (CNS) injury, which has long been implicated as a major impediment to the CNS regeneration. However, the factors affecting such scar formation remain to be elucidated. We herein demonstrate that the extracellular matrix protein periostin (POSTN) is a key player in scar formation after traumatic spinal cord injury (SCI). Using high-throughput RNA sequencing data sets, we found that the genes involved in the extracellular region, such as POSTN, were significantly expressed in the injured spinal cord. The expression of POSTN peaked at 7 days after SCI, predominantly in the scar-forming pericytes. Notably, we found that genetic deletion of POSTN in mice reduced scar formation at the lesion site by suppressing the proliferation of the pericytes. Conversely, we found that recombinant POSTN promoted the migration capacity of the monocytes/macrophages and increased the expression of tumor necrosis factor-α from the monocytes/macrophages in vitro, which facilitated the proliferation of pericytes. Furthermore, we revealed that the pharmacological blockade of POSTN suppressed scar formation and improved the long-term functional outcome after SCI. Our findings suggest a potential mechanism whereby POSTN regulates the scar formation after SCI and provide significant evidence that POSTN is a promising therapeutic target for CNS injury.

Pathophysiological aldosterone levels modify the secretory activity of cardiac progenitor cells

Cardiac progenitor cells (CPCs) trigger regenerative processes via paracrine mechanisms in response to changes in their environment. In the present study we explored alterations in the secretory activity of CPCs induced by raised aldosterone levels symptomatic for heart failure. The cytokine profile of the supernatant of CPCs that were treated with the mineralocorticoid showed an induction of interleukin-6 secretion. Mass spectrometric analyses revealed an increase in the abundance of secreted proteins associated with regeneration and cell migration like gelsolin and galectin-1. Differential regulation of proteins associated with the extracellular matrix further points to an activation of cell migration. In response to supernatant, migration and proliferation were induced in CPCs, indicating a potential role of paracrine factors in the activation of CPCs from other regions of the heart or extra-cardiac sources. Changes in the secretory activity of CPCs might aim to compensate for the detrimental actions of aldosterone in heart failure.

Integrins and heparan sulfate proteoglycans on hepatic stellate cells (HSC) are novel receptors for HSC-derived exosomes

Exosomes mediate intercellular microRNA delivery between hepatic stellate cells (HSC), the principal fibrosis-producing cells in the liver. The purpose of this study was to identify receptors on HSC for HSC-derived exosomes, which bind to HSC rather than to hepatocytes. Our findings indicate that exosome binding to HSC is blocked by treating HSC with RGD, EDTA, integrin αv or β1 siRNAs, integrin αvβ3 or α5β1 neutralizing antibodies, heparin, or sodium chlorate. Furthermore, exosome cargo delivery and exosome-regulated functions in HSC, including expression of fibrosis- or activation-associated genes and/or miR-214 target gene regulation, are dependent on cellular integrin αvβ3, integrin α5β1, or heparan sulfate proteolgycans (HSPG). Thus, integrins and HSPG mediate the binding of HSC-derived exosomes to HSC as well as the delivery and intracellular action of the exosomal payload.

Molecular Cues Guiding Matrix Stiffness in Liver Fibrosis

Tissue and matrix stiffness affect cell properties during morphogenesis, cell growth, differentiation, and migration and are altered in the tissue remodeling following injury and the pathological progression. However, detailed molecular mechanisms underlying alterations of stiffness in vivo are still poorly understood. Recent engineering technologies have developed powerful techniques to characterize the mechanical properties of cell and matrix at nanoscale levels. Extracellular matrix (ECM) influences mechanical tension and activation of pathogenic signaling during the development of chronic fibrotic diseases. In this short review, we will focus on the present knowledge of the mechanisms of how ECM stiffness is regulated during the development of liver fibrosis and the molecules involved in ECM stiffness as a potential therapeutic target for liver fibrosis.