The role of periostin in tissue remodeling across health and disease

Periostin expression in neoplastic and non-neoplastic diseases of bone and joint

BACKGROUND

Periostin is a matricellular protein that is expressed in bone and joint tissues. To determine the expression of periostin in primary bone tumours and to assess whether it plays a role in tumour progression, we carried out immunohistochemistry and ELISA for periostin in a range of neoplastic and non-neoplastic bone and joint lesions.

METHODS

140 formalin-fixed paraffin-embedded sections of bone tumours and tumour-like lesions were stained by an indirect immunoperoxidase technique with a polyclonal anti-periostin antibody. Periostin expression was also assessed in rheumatoid arthritis (RA) and non-inflammatory osteoarthritis (OA) synovium and synovial fluid immunohistochemistry and ELISA respectively.

RESULTS

Periostin was most strongly expressed in osteoid/woven bone of neoplastic and non-neoplastic bone-forming lesions, including osteoblastoma, osteosarcoma, fibrous dysplasia, osteofibrous dysplasia, fracture callus and myositis ossificans, and mineralised chondroid matrix/woven bone in chondroblastoma and clear cell chondrosarcoma. Reactive host bone at the edge of growing tumours, particularly in areas of increased vascularity and fibrosis, also stained strongly for periostin. Vascular elements in RA synovium strongly expressed periostin, and synovial fluid levels of periostin were higher in RA than OA.

CONCLUSIONS

In keeping with its known role in modulating the synthesis of collagen and other extracellular matrix proteins in bone, strong periostin expression was noted in benign and malignant lesions forming an osteoid or osteoid-like matrix. Periostin was also noted in other bone tumours and was found in areas of reactive bone and increased vascularity at the edge of growing tumours, consistent with its involvement in tissue remodelling and angiogenesis associated with tumour progression.

Periostin Promotes Fibroblast Migration and Inhibits Muscle Repair After Skeletal Muscle Injury

BACKGROUND

Skeletal muscle injury (SMI) can cause physical disability due to insufficient recovery of the muscle. The development of muscle fibrosis after SMI has been widely regarded as a principal cause of this failure to recover. Periostin (Postn) exacerbates tissue fibrosis in various organs. We investigated whether Postn is involved in the pathophysiology after SMI.

METHODS

Partial laceration injuries of the gastrocnemius were created in wild-type (WT) and Postn knockout (Postn) mice. We examined the expression of the Postn gene before and after SMI. Regeneration and fibrosis of skeletal muscle were evaluated by histological analyses, and recovery of muscle strength was measured by physiological testing. Immunohistochemistry was used to examine the number and proliferative potential of infiltrating fibroblasts in injured muscle. A trans-well migration assay was used to assess the migration capability of fibroblasts. Control immunoglobulin G (IgG) or Postn-neutralizing antibody (Postn-nAb) was injected into injured muscle at 7 and 14 days after injury (dpi). We evaluated the effects of Postn-nAb on muscle repair after SMI.

RESULTS

The expression of Postn was dramatically upregulated after SMI. Compared with WT mice, Postn mice had improved muscle recovery and attenuated fibrosis as well as a significantly reduced number of infiltrating fibroblasts. The proliferative potential of these fibroblasts in WT and Postn mice was comparable at 14 dpi; however, the migration capability of fibroblasts was significantly enhanced in the presence of Postn (mean, 258%; 95% confidence interval, 183% to 334%). Moreover, the administration of Postn-nAb inhibited fibroblast infiltration and promoted muscle repair after SMI.

CONCLUSIONS

Postn exacerbates fibrotic scar formation through the promotion of fibroblast migration into injured muscle after SMI. Treatment with Postn-nAb is effective for attenuating fibrosis and improving muscle recovery after SMI.

CLINICAL RELEVANCE

Our findings may provide a potential therapeutic strategy to enhance muscle repair and functional recovery after SMI.

Longitudinal evaluation of serum periostin levels in patients after large-artery atherosclerotic stroke: A prospective observational study

Increasing evidence supports the involvement of periostin in the pathophysiological processes of stroke and atherosclerosis. The aim of this study was to assess circulating periostin levels at different times after large-artery atherosclerotic (LAA) stroke and their association with stroke. Serum periostin levels were measured using enzyme-linked immunosorbent assay on day 1 in 162 patients with LAA stroke and in 108 age- and sex-matched controls, on day 6 after stroke in 134 patients, and during the 4th week after stroke in 46 of the 162 patients. Stroke severity was determined using the National Institutes of Health Stroke Scale (NIHSS), and the stroke volume was measured. Outcome at 3 months was measured using the modified Rankin Scale (mRS). Our results indicated that periostin levels increased significantly on day 6 after stroke, and this increasing trend persisted for at least 4 weeks after the event. In addition, the increase in periostin levels was positively correlated with the NIHSS scores and stroke volume, but not with the mRS scores after adjusting for the NIHSS scores. In conclusion, these findings suggest that the increase in serum periostin levels observed after stroke may be associated with the stroke severity in patients with LAA stroke.

Serum periostin levels following small bone fractures, long bone fractures and joint replacements: an observational study

BACKGROUND

In asthma, serum periostin may potentially be used as a biomarker in the management of patients with Type-2 eosinophilic airway inflammation. However, serum periostin may be influenced by factors other than Type 2 inflammation, potentially confounding its interpretation. We aimed to measure change in periostin following bone injury.

METHODS

102 adults without asthma were recruited into three groups: joint replacement surgery, long bone fracture, short bone fracture. Participants underwent seven measurements of serum periostin over 26 weeks after bone injury, and prior to surgery in the joint replacement group. Differences in periostin were measured using a ratio of geometric mean (RGM), with comparison made with pre-surgery (joint replacement) or 26 week (long and short fracture) reference measurements.

RESULTS

In the joint replacement group, periostin fell within 48 h (RGM 0.80, 95% CI 0.75-0.86), then increased to a maximum at 8 weeks (RGM 1.89, 1.77-2.02) and by 26 weeks remained above the reference measurement (RGM 1.27, 1.19-1.36). In the long bone fracture group, periostin was reduced at 48 h (RGM 0.76, 0.71-0.83) and then progressively increased to a maximum at 8 weeks (RGM 1.15, 1.06-1.23) compared with the reference measurement. In the short bone fracture group, periostin was reduced at 48 h (RGM 0.9, 0.85-0.95) but was not different from after week 1 compared with the reference measurement.

CONCLUSIONS

Serum periostin levels are influenced by bone injury. The timing and extent of bone injury needs consideration if periostin is used as a biomarker in the management of eosinophilic asthma.Trial registration This trial was prospectively registered with the Australia New Zealand Trials Registry on Feb 7 2014, (ACTRN12614000151639: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363881).

Control of cytokine-driven eosinophil migratory behavior by TGF-beta-induced protein (TGFBI) and periostin

Periostin, which is induced by interleukin (IL)-13, is an extracellular matrix (ECM) protein that supports αMβ2 integrin-mediated adhesion and migration of IL-5-stimulated eosinophils. Transforming growth factor (TGF)-β-induced protein (TGFBI) is a widely expressed periostin paralog known to support monocyte adhesion. Our objective was to compare eosinophil adhesion and migration on TGFBI and periostin in the presence of IL-5-family cytokines. Eosinophil adhesion after 1 h and random motility over 20 h in the presence of various concentrations of IL-5, IL-3, or granulocyte macrophage-colony stimulating factor (GM-CSF) were quantified in wells coated with various concentrations of TGFBI or periostin. Results were compared to video microscopy of eosinophils. Cytokine-stimulated eosinophils adhered equivalently well to TGFBI or periostin in a coating concentration-dependent manner. Adhesion was blocked by anti-αMβ2 and stimulated at the lowest concentration by GM-CSF. In the motility assay, periostin was more potent than TGFBI, the coating-concentration effect was bimodal, and IL-3 was the most potent cytokine. Video microscopy revealed that under the optimal coating condition of 5 μg/ml periostin, most eosinophils migrated persistently and were polarized and acorn-shaped with a ruffling forward edge and granules gathered together, in front of the nucleus. On 10 μg/ml periostin or TGFBI, more eosinophils adopted a flattened pancake morphology with dispersed granules and nuclear lobes, and slower migration. Conversion between acorn and pancake morphologies were observed. We conclude that TGFBI or periostin supports two modes of migration by IL-5 family cytokine-activated eosinophils. The rapid mode is favored by intermediate protein coatings and the slower by higher coating concentrations. We speculate that eosinophils move by haptotaxis up a gradient of adhesive ECM protein and then slow down to surveil the tissue.

Sodium Tanshinone IIA Sulfonate Prevents Angiotensin II-Induced Differentiation of Human Atrial Fibroblasts into Myofibroblasts

Differentiation of atrial fibroblasts into myofibroblasts plays a critical role in atrial fibrosis. Sodium tanshinone IIA sulfonate (DS-201), a water-soluble derivative of tanshinone IIA, has been shown to have potent antifibrotic properties. However, the protective effects of DS-201 on angiotensin II- (Ang II-) induced differentiation of atrial fibroblasts into myofibroblasts remain to be elucidated. In this study, human atrial fibroblasts were stimulated with Ang II in the presence or absence of DS-201. Then, α-smooth muscle actin (α-SMA), collagen I, and collagen III expression and reactive oxygen species (ROS) generation were measured. The expression of transforming growth factor-β1 (TGF-β1) and the downstream signaling of TGF-β1, such as phosphorylation of Smad2/3, were also determined. The results demonstrated that DS-201 significantly prevented Ang II-induced human atrial fibroblast migration and decreased Ang II-induced α-SMA, collagen I, and collagen III expression. Furthermore, increased production of ROS and expression of TGF-β1 stimulated by Ang II were also significantly inhibited by DS-201. Consistent with these results, DS-201 significantly inhibited Ang II-evoked Smad2/3 phosphorylation and periostin expression. These results and the experiments involving N-acetyl cysteine (antioxidant) and an anti-TGF-β1 antibody suggest that DS-201 prevent Ang II-induced differentiation of atrial fibroblasts to myofibroblasts, at least in part, through suppressing oxidative stress and inhibiting the activation of TGF-β1 signaling pathway. All of these data indicate the potential utility of DS-201 for the treatment of cardiac fibrosis.

Periostin promotes liver fibrogenesis by activating lysyl oxidase in hepatic stellate cells

Liver fibrosis arises from dysregulated wound healing due to persistent inflammatory hepatic injury. Periostin is a nonstructural extracellular matrix protein that promotes organ fibrosis in adults. Here, we sought to identify the molecular mechanisms in periostin-mediated hepatic fibrosis. Hepatic fibrosis in periostin^-/- mice was attenuated as evidenced by significantly reduced collagen fibril density and liver stiffness compared with those in WT controls. A single dose of carbon tetrachloride caused similar acute liver injury in periostin^-/- and WT littermates, and we did not detect significant differences in transaminases and major fibrosis-related hepatic gene expression between these two genotypes. Activated hepatic stellate cells (HSCs) are the major periostin-producing liver cell type. We found that in primary rat HSCs in vitro, periostin significantly increases the expression levels and activities of lysyl oxidase (LOX) and lysyl oxidase-like (LOXL) isoforms 1-3. Periostin also induced expression of intra- and extracellular collagen type 1 and fibronectin in HSCs. Interestingly, periostin stimulated phosphorylation of SMAD2/3, which was sustained despite short hairpin RNA-mediated knockdown of transforming growth factor β (TGFβ) receptor I and II, indicating that periostin-mediated SMAD2/3 phosphorylation is independent of TGFβ receptors. Moreover, periostin induced the phosphorylation of focal adhesion kinase (FAK) and AKT in HSCs. Notably, siRNA-mediated FAK knockdown failed to block periostin-induced SMAD2/3 phosphorylation. These results suggest that periostin promotes enhanced matrix stiffness in chronic liver disease by activating LOX and LOXL, independently of TGFβ receptors. Hence, targeting periostin may be of therapeutic benefit in combating hepatic fibrosis.

Key Pathways and Regulators of Vitamin K Function and Intermediary Metabolism

Vitamin K (VK) is an essential cofactor for the post-translational conversion of peptide-bound glutamate to γ-carboxyglutamate. The resultant vitamin K-dependent proteins are known or postulated to possess a variety of biological functions, chiefly in the maintenance of hemostasis. The vitamin K cycle is a cellular pathway that drives γ-carboxylation and recycling of VK via γ-carboxyglutamyl carboxylase (GGCX) and vitamin K epoxide reductase (VKOR), respectively. In this review, we show how novel molecular biological approaches are providing new insights into the pathophysiological mechanisms caused by rare mutations of both GGCX and VKOR. We also discuss how other protein regulators influence the intermediary metabolism of VK, first through intestinal absorption and second through a pathway that converts some dietary phylloquinone to menadione, which is prenylated to menaquinone-4 (MK-4) in target tissues by UBIAD1. The contribution of MK-4 synthesis to VK functions is yet to be revealed.

Fascinating Fasciclins: A Surprisingly Widespread Family of Proteins that Mediate Interactions between the Cell Exterior and the Cell Surface

The Fasciclin 1 (FAS1) domain is an ancient structural motif in extracellular proteins present in all kingdoms of life and particularly abundant in plants. The FAS1 domain accommodates multiple interaction surfaces, enabling it to bind different ligands. The frequently observed tandem FAS1 arrangement might both positively and negatively regulate ligand binding. Additional protein domains and post-translational modifications are partially conserved between different evolutionary clades. Human FAS1 family members are associated with multiple aspects of health and disease. At the cellular level, mammalian FAS1 proteins are implicated in extracellular matrix structure, cell to extracellular matrix and cell to cell adhesion, paracrine signaling, intracellular trafficking and endocytosis. Mammalian FAS1 proteins bind to the integrin family of receptors and to protein and carbohydrate components of the extracellular matrix. FAS1 protein encoding plant genes exert effects on cellulosic and non-cellulosic cell wall structure and cellular signaling but to establish the modes of action for any plant FAS1 protein still requires biochemical experimentation. In fungi, eubacteria and archaea, the differential presence of FAS1 proteins in closely related organisms and isolated biochemical data suggest functions in pathogenicity and symbiosis. The inter-kingdom comparison of FAS1 proteins suggests that molecular mechanisms mediating interactions between cells and their environment may have evolved at the earliest known stages of evolution.

Invasion-Related Factors as Potential Diagnostic and Therapeutic Targets in Oral Squamous Cell Carcinoma-A Review

It is well recognized that the presence of cervical lymph node metastasis is the most important prognostic factor in oral squamous cell carcinoma (OSCC). In solid epithelial cancer, the first step during the process of metastasis is the invasion of cancer cells into the underlying stroma, breaching the basement membrane (BM)—the natural barrier between epithelium and the underlying extracellular matrix (ECM). The ability to invade and metastasize is a key hallmark of cancer progression, and the most complicated and least understood. These topics continue to be very active fields of cancer research. A number of processes, factors, and signaling pathways are involved in regulating invasion and metastasis. However, appropriate clinical trials for anti-cancer drugs targeting the invasion of OSCC are incomplete. In this review, we summarize the recent progress on invasion-related factors and emerging molecular determinants which can be used as potential for diagnostic and therapeutic targets in OSCC.

Periostin, a signal transduction intermediate in TGF-β-induced EMT in U-87MG human glioblastoma cells, and its inhibition by anthocyanidins

Periostin is a secreted protein that is highly expressed in glioblastoma cells as compared to normal brain tissue, and is therefore considered as a potential biomarker in therapeutic modalities. Its contribution in the cancer cells invasive phenotype is, however, poorly understood. This work investigates the role of periostin in U-87 MG glioblastoma cell invasion, cell migration and in Transforming Growth Factor β (TGF-β)-induced epithelial-mesenchymal transition (EMT). Periostin gene silencing, using small interfering RNA, decreased TGF-β-induced mesenchymal marker expression of fibronectin and vimentin, partly through reduced Smad2, Akt and Fak phosphorylation as well as U-87 MG cell invasion and migration. The effects of anthocyanidins, the most abundant diet-derived flavonoids, were examined on periostin-mediated downstream signaling pathways. Anthocyanidins were found to decrease periostin expression whether added under pre-, co- or post-treatment conditions along with TGF-β, and altered the Akt and Fak signaling pathways. These effects were similar to Galunisertib (LY2157299), a small molecule inhibitor of the TGF-β receptor I kinase. Taken together, our data demonstrate that periostin acts as a central element in TGF-β-induced EMT, which can be prevented by diet-derived anthocyanidins.

Periostin attenuates tumor growth by inducing apoptosis in colitis-related colorectal cancer

Inflammatory bowel diseases, which are multifactorial autoimmune colitis diseases, are occurring with increasing prevalence. One of the most serious complications of these diseases is colorectal cancer. Here we investigated the role of periostin (Postn), a matricellular protein that interacts with various integrin molecules on the cell surface, in colitis-induced colorectal cancer. Immunohistochemistry of mouse and human colorectal cancer samples revealed that Postn was expressed in the stroma and was upregulated in close proximity to the cancer cells. The colonic tumorigenesis in an inflammation-related colon carcinogenesis mouse model was increased in Postn knock-out (Postn^−/−) mice compared to Postn^+/+ mice. Although no difference was found in the degree of colitis between Postn^+/+ and Postn^−/− mice, Postn inhibited tumor growth and induced the apoptosis of mouse rectal cancer cells in vitro. Furthermore, fewer apoptotic colorectal cancer cells were observed in Postn^−/− than in Postn^+/+ mice. These data suggested that Postn has an anti-tumor effect on colitis-induced colorectal cancer.

Molecular influence of anterior cruciate ligament tear remnants on chondrocytes: a biologic connection between injury and osteoarthritis

OBJECTIVE

Anterior cruciate ligament (ACL) injury initiates a cascade of events often leading to osteoarthritis (OA). ACL reconstruction does not alter the course of OA, suggesting that heightened OA risk is likely due to factors in addition to the joint instability. We showed that torn ACL remnants express periostin (POSTN) in the acute phase of injury. Considering that ACL injury predisposes to OA and that POSTN is associated with cartilage metabolism, we hypothesize that ACL injury affects chondrocytes via POSTN.

DESIGN

Cartilage was obtained from osteoarthritic patients and ACL remnants were collected from patients undergoing ACL reconstruction. Crosstalk between ACL remnants and chondrocytes was studied in a transwell co-culture system. Expression of POSTN and other anabolic and catabolic genes was assessed via real-time polymerase chain reaction (PCR). Immunostaining for periostin was performed in human and mouse cartilage. The impact of exogenous periostin and siRNA-mediated ablation of periostin on matrix metabolism and cell migration was examined. Furthermore, the effect of anabolic (transforming growth factor beta 1 [TGF-β1]) and catabolic (interleukin 1 beta [IL-1β]) factors on POSTN expression was investigated.

RESULTS

ACL remnants induced expression of POSTN, MMP13 and ADAMTS4. Periostin levels were significantly higher in osteoarthritic compared to normal cartilage. Exogenous periostin induced MMP13 expression and cell migration, and repressed COL1A1 expression while POSTN knockdown inhibited expression of both anabolic and catabolic genes and impeded cell migration. TGF-β1 and IL-1β treatment did not alter POSTN expression but influenced chondrocyte metabolism as determined by quantification of anabolic and catabolic genes via real-time PCR.

CONCLUSIONS

ACL remnants can exert paracrine effects on cartilage, altering cellular homeostasis. Over time, this metabolic imbalance could contribute to OA development.

Periostin antisense oligonucleotide suppresses bleomycin-induced formation of a lung premetastatic niche for melanoma

Metastasis is the leading cause of cancer death. A tumor‐supportive microenvironment, or premetastatic niche, at potential secondary tumor sites plays an important role in metastasis, especially in tumor cell colonization. Although a fibrotic milieu is known to promote tumorigenesis and metastasis, the underlying molecular contributors to this effect have remained unclear. Here we show that periostin, a component of the extracellular matrix that functions in tissue remodeling, has a key role in formation of a fibrotic environment that promotes tumor metastatic colonization. We found that periostin was widely expressed in fibrotic lesions of mice with bleomycin‐induced lung fibrosis, and that up‐regulation of periostin expression coincided with activation of myofibroblasts positive for α‐smooth muscle actin. We established a lung metastasis model for B16 murine melanoma cells and showed that metastatic colonization of the lung by these cells was markedly promoted by bleomycin‐induced lung fibrosis. Inhibition of periostin expression by giving an intratracheal antisense oligonucleotide targeting periostin mRNA was found to suppress bleomycin‐induced lung fibrosis and thereby to attenuate metastatic colonization of the lung by melanoma cells. Our results indicate that periostin is a key player in the development of bleomycin‐induced fibrosis and consequent enhancement of tumor cell colonization in the lung. Our results therefore implicate periostin as a potential target for prevention or treatment of lung metastasis.

Recent Understandings of Biology, Prophylaxis and Treatment Strategies for Hypertrophic Scars and Keloids

Hypertrophic scars and keloids are fibroproliferative disorders that may arise after any deep cutaneous injury caused by trauma, burns, surgery, etc. Hypertrophic scars and keloids are cosmetically problematic, and in combination with functional problems such as contractures and subjective symptoms including pruritus, these significantly affect patients’ quality of life. There have been many studies on hypertrophic scars and keloids; but the mechanisms underlying scar formation have not yet been well established, and prophylactic and treatment strategies remain unsatisfactory. In this review, the authors introduce and summarize classical concepts surrounding wound healing and review recent understandings of the biology, prevention and treatment strategies for hypertrophic scars and keloids.

Transcriptome comparison of meniscus from patients with and without osteoarthritis

OBJECTIVE

To assess the impact of osteoarthritis (OA) on the meniscus by comparing transcripts and biological processes in the meniscus between patients with and without OA.

DESIGN

RNA microarrays were used to identify transcripts differentially expressed (DE) in meniscus obtained from 12 OA and 12 non-OA patients. The non-OA specimens were obtained at the time of arthroscopic partial meniscectomy. Real-time PCR was performed on selected transcripts. Biological processes and gene-networking was examined computationally. Transcriptome signatures were mapped with 37 OA-related transcripts to evaluate how meniscus gene expression relates to that of OA cartilage.

RESULTS

We identified 168 transcripts significantly DE between OA (75 elevated, 93 repressed) and non-OA samples (≥1.5-fold). Among these, CSN1S1, COL10A1, WIF1, and SPARCL1 were the most prominent transcripts elevated in OA meniscus, POSTN and VEGFA were most highly repressed in OA meniscus. Transcripts elevated in OA meniscus represented response to external stimuli, cell migration and cell localization while those repressed in OA meniscus represented histone deacetylase activity (related to epigenetics) and skeletal development. Numerous long non-coding RNAs (lncRNAs) were DE between the two groups. When segregated by OA-related transcripts, two distinct clustering patterns appeared: OA meniscus appeared to be more inflammatory while non-OA meniscus exhibited a "repair" phenotype.

CONCLUSIONS

Numerous transcripts with potential relevance to the pathogenesis of OA are DE in OA and non-OA meniscus. These data suggest an involvement of epigenetically regulated histone deacetylation in meniscus tears as well as expression of lncRNAs. Patient clustering based on transcripts related to OA in articular cartilage confirmed distinct phenotypes between injured (non-OA) and OA meniscus.

Periosteum contains skeletal stem cells with high bone regenerative potential controlled by Periostin

Bone regeneration relies on the activation of skeletal stem cells (SSCs) that still remain poorly characterized. Here, we show that periosteum contains SSCs with high bone regenerative potential compared to bone marrow stromal cells/skeletal stem cells (BMSCs) in mice. Although periosteal cells (PCs) and BMSCs are derived from a common embryonic mesenchymal lineage, postnatally PCs exhibit greater clonogenicity, growth and differentiation capacity than BMSCs. During bone repair, PCs can efficiently contribute to cartilage and bone, and integrate long-term after transplantation. Molecular profiling uncovers genes encoding Periostin and other extracellular matrix molecules associated with the enhanced response to injury of PCs. Periostin gene deletion impairs PC functions and fracture consolidation. Periostin-deficient periosteum cannot reconstitute a pool of PCs after injury demonstrating the presence of SSCs within periosteum and the requirement of Periostin in maintaining this pool. Overall our results highlight the importance of analyzing periosteum and PCs to understand bone phenotypes.

The periosteum, a tissue lining the bone surface, and the bone marrow are known to contain bone-forming cells. Here the authors show that skeletal stem cells reside in the mouse periosteum, and that periosteal cells have common embryonic origins with bone marrow stromal/stem cells (BMSCs), but are better at bone repair and long-term integration than BMSCs.

Hypoxia promotes glioma-associated macrophage infiltration via periostin and subsequent M2 polarization by upregulating TGF-beta and M-CSFR

Tumor-associated macrophages (TAMs) are enriched in gliomas and help create a tumor-immunosuppressive microenvironment. A distinct M2-skewed type of macrophages makes up the majority of glioma TAMs, and these cells exhibit pro-tumor functions. Gliomas contain large hypoxic areas, and the presence of a correlation between the density of M2-polarized TAMs and hypoxic areas suggests that hypoxia plays a supportive role during TAM recruitment and induction. Here, we investigated the effects of hypoxia on human macrophage recruitment and M2 polarization. We also investigated the influence of the HIF inhibitor acriflavine (ACF) on M2 TAM infiltration and tumor progression in vivo. We found that hypoxia increased periostin (POSTN) expression in glioma cells and promoted the recruitment of macrophages. Hypoxia-inducible POSTN expression was increased by TGF-α via the RTK/PI3K pathway, and this effect was blocked by treating hypoxic cells with ACF. We also demonstrated that both a hypoxic environment and hypoxia-treated glioma cell supernatants were capable of polarizing macrophages toward a M2 phenotype. ACF partially reversed the M2 polarization of macrophages by inhibiting the upregulation of M-CSFR in macrophages and TGF-β in glioma cells under hypoxic conditions. Administering ACF also ablated tumor progression in vivo. Our findings reveal a mechanism that underlies hypoxia-induced TAM enrichment and M2 polarization and suggest that pharmacologically inhibiting HIFs may reduce M2-polarized TAM infiltration and glioma progression.

Targeted Therapy for Severe Asthma: Identifying the Right Patients

Asthma affects over 300 million people worldwide. Most asthmatics are well controlled with inhaled corticosteroids and long-acting beta-agonists; however, a proportion of patients are unresponsive and attain limited disease control. This group represents a considerable healthcare and financial burden, particularly patients who experience frequent exacerbations and require hospital admission. Development of new biological agents and disease biomarkers has provided novel avenues for treatment. These treatments have been highly successful, reducing exacerbations and yielding modest improvements in quality of life and lung function. However, only a proportion of severe asthmatics respond to this targeted treatment, highlighting the heterogeneity of severe asthma. One of the first biological therapies targeted immunoglobulin E (IgE) and demonstrated modest benefit but could only be used in a subgroup of patients. Recent research has shown that treatment aimed at the T helper-2-(Th₂)-high pathways and cytokines such as interleukin (IL)-5, IL-4, and IL-13 may also be effective in another partially overlapping subgroup. A blood eosinophil count over a defined threshold (generally ≥300 cells/μl) was a reliable biomarker and identified the majority of responders in this group. Further discovery and validation of biological markers to define asthmatic phenotypes that may benefit from biological treatments remain an area of intense interest and research. We review the latest information pertaining to biological agents and demonstrate how patient responders may potentially be identified for treatment.

Serum but not exhaled breath condensate periostin level is increased in competitive athletes

INTRODUCTION

Periostin is a matricellular protein expressed by many tissues. Its release may be enhanced, among others, through mechanical stimulation of muscles and bones as well as by cytokines of allergic inflammation.

OBJECTIVES

Our aim was to assess periostin levels in serum and exhaled breath condensate (EBC) of professional athletes, asthmatics and healthy controls. We also sought to determine whether acute treadmill exercise influences serum and EBC periostin.

METHODS

Study groups included 9 competitive swimmers, 10 mild-to-moderate asthmatics and 7 healthy controls. Athletes were assessed twice (in- and off-training period) while asthmatics and controls in one time-point. Data on demographics, allergy symptoms and exercise load were acquired through Allergy Questionnaire for Athletes (AQUA) and International Physical Activity Questionnaire (IPAQ). Serum and EBC were collected before and after treadmill exercise challenge.

RESULTS

Baseline serum periostin in swimmers during training period was significantly higher (5- to 7-fold) than in asthmatics (P = .01) and controls (P < .05). In EBC, lowest periostin levels were seen in athletes in-training as compared with off-training period (P < .01) and with asthmatics (P < .03). Acute bout of exercise did not induce significant changes neither in serum nor in EBC periostin in any group.

CONCLUSION

Increased serum, but not EBC, periostin levels in competitive athletes are probably because of permanently increased exercise load leading to stimulation, injury and regeneration of musculoskeletal tissues. Periostin may be considered marker of long-term exercise overload after confirmation in larger groups.

Severe bronchial asthma in children: a review of novel biomarkers used as predictors of the disease

Severe asthma or therapy-resistant asthma in children is a heterogeneous disease that affects all age-groups. Given its heterogeneity, precision in diagnosis and treatment has become imperative, in order to achieve better outcomes. If one is thus able to identify specific patient phenotypes and endotypes using the appropriate biomarkers, it will assist in providing the patient with more personalized and appropriate treatment. However, there appears to be a huge diagnostic gap in severe asthma, as there is no single test yet that accurately determines disease phenotype. In this paper, we review the published literature on some of these biomarkers and their possible role in bridging this diagnostic gap. We also highlight the cellular and molecular mechanisms involved in severe asthma, in order to show the basis for the novel biomarkers. Some markers useful for monitoring therapy and assessing airway remodeling in the disease are also discussed. A review of the literature was conducted with PubMed to gather baseline data on the subject. The literature search extended to articles published within the last 40 years. Although biomarkers specific to different severe asthma phenotypes have been identified, progress in their utility remains slow, because of several disease mechanisms, the variation of biomarkers at different levels of inflammation, changes in relying on one test over time (eg, from sputum eosinophilia to blood eosinophilia), and the degree of invasive tests required to collect biomarkers, which limits their applicability in clinical settings. In conclusion, several biomarkers remain useful in recognizing various asthma phenotypes. However, due to disease heterogeneity, identification and utilization of ideal and defined biomarkers in severe asthma are still inconclusive. The development of novel serum/sputum-based biomarker panels with enhanced sensitivity and specificity may lead to prompt diagnosis of the disease in the future.

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.

Advantages of RNA-seq compared to RNA microarrays for transcriptome profiling of anterior cruciate ligament tears

Microarrays and RNA-seq are at the forefront of high throughput transcriptome analyses. Since these methodologies are based on different principles, there are concerns about the concordance of data between the two techniques. The concordance of RNA-seq and microarrays for genome-wide analysis of differential gene expression has not been rigorously assessed in clinically derived ligament tissues. To demonstrate the concordance between RNA-seq and microarrays and to assess potential benefits of RNA-seq over microarrays, we assessed differences in transcript expression in anterior cruciate ligament (ACL) tissues based on time-from-injury. ACL remnants were collected from patients with an ACL tear at the time of ACL reconstruction. RNA prepared from torn ACL remnants was subjected to Agilent microarrays (N = 24) and RNA-seq (N = 8). The correlation of biological replicates in RNA-seq and microarrays data was similar (0.98 vs. 0.97), demonstrating that each platform has high internal reproducibility. Correlations between the RNA-seq data and the individual microarrays were low, but correlations between the RNA-seq values and the geometric mean of the microarrays values were moderate. The cross-platform concordance for differentially expressed transcripts or enriched pathways was linearly correlated (r = 0.64). RNA-Seq was superior in detecting low abundance transcripts and differentiating biologically critical isoforms. Additional independent validation of transcript expression was undertaken using microfluidic PCR for selected genes. PCR data showed 100% concordance (in expression pattern) with RNA-seq and microarrays data. These findings demonstrate that RNA-seq has advantages over microarrays for transcriptome profiling of ligament tissues when available and affordable. Furthermore, these findings are likely transferable to other musculoskeletal tissues where tissue collection is challenging and cells are in low abundance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:484-497, 2018.

Heterogeneous Periostin Expression in Different Histological Variants of Papillary Thyroid Carcinoma

Background

Periostin (PN) epithelial and stromal overexpression in tumor pathology has been studied according to tumor growth, angiogenesis, invasiveness, and metastasis, but a limited number of studies address PN in thyroid tumors.

Aim

Our study aimed to analyze PN expression in different histological variants of PTC and to correlate its expression with the clinicopathological prognostic factors.

Material and Methods

PN expression has been immunohistochemically assessed in 50 cases of PTC (conventional, follicular, oncocytic, macrofollicular, and tall cell variants), in tumor epithelial cells and intratumoral stroma. The association between PN expression and clinicopathological characteristics has been evaluated.

Results

Our results show that PTC presented different patterns of PN immunoreaction, stromal PN being significantly associated with advanced tumor stage and extrathyroidal extension. No correlations were found between PN overexpression in tumor epithelial cells and clinicopathological features, except for specific histological variants, the highest risk of poor outcome being registered for the conventional subtype in comparison to the oncocytic type.

Conclusions

Our study demonstrates differences in PN expression in histological subtypes of PTC. Our results plead in favor of a dominant protumorigenic role of stromal PN, while the action of epithelial PN is less noticeable.

Experimental Inhibition of Periostin Attenuates Kidney Fibrosis

BACKGROUND

Periostin is responsible for tissue regeneration, fibrosis, and wound healing via its interaction with integrin. Recently, the role of periostin has been shown to contribute to fibrosis in chronic kidney disease. We investigated the role of periostin and the effect of periostin blockade in renal fibrogenesis.

METHODS

We investigated the function of periostin in vivo in wild-type and periostin-null mice (Postn-KO) in a unilateral ureteral obstruction (UUO) model. For the in vitro experiments, primary cultured inner medullary collecting duct cells from the wild-type and Postn-KO mice were used.

RESULTS

Periostin expression was strongly induced by UUO in the wild-type mice. UUO induced renal fibrosis and morphological changes in the obstructed kidney of wild-type mice, whereas global knockout of periostin reduced fibrosis induced by UUO and improved kidney structure. Fibrosis- and inflammation-related mRNA were significantly induced in the wild-type mice and were decreased in the Postn-KO mice. Additionally, α-smooth muscle actin expression was increased following the administration of recombinant periostin in vitro. The effect of periostin blockade was examined using 2 methods. The integrin blockade peptide decreased fibrosis-related gene expression in in vitro experiments. Anti-periostin polyclonal antibody attenuated renal fibrosis induced by UUO through changes in transforming growth factor-β signaling and the inflammatory and apoptotic pathways.

CONCLUSION

Periostin is a marker of renal fibrosis and may augment the progression of fibrogenesis as an extracellular matrix protein. Periostin blockade effectively attenuated renal fibrogenesis. Thus, periostin inhibition may be a therapeutic strategy for the amelioration of renal disease progression.

Introductory review: periostin-gene and protein structure

Although many studies have described the role of periostin in various diseases, the function of the periostin protein structures derived from alternative splicing and proteinase cleavage at the C-terminal remain unknown. Further experiments revealing the protein structures that are highly related to diseases are essential to understand the function of periostin in depth, which would accelerate its clinical application by establishing new approaches for curing intractable diseases. Furthermore, this understanding would enhance our knowledge of novel functions of periostin related to stemness and response to mechanical stress.

The multifaceted role of periostin in priming the tumor microenvironments for tumor progression

Tumor microenvironment consists of tumor cells, stromal cells, extracellular matrix and a plethora of soluble components. The complex array of interactions between tumor cells and their surrounding tumor microenvironments contribute to the determination of the fate of tumor cells during tumorigenesis and metastasis. Matricellular protein periostin is generally absent in most adult tissues but is highly expressed in tumor microenvironments. Current evidence reveals that periostin plays a critical role in establishing and remodeling tumor microenvironments such as the metastatic niche, cancer stem cell niche, perivascular niche, pre-metastatic niche, fibrotic microenvironment and bone marrow microenvironment. Here, we summarize the current knowledge of the multifaceted role of periostin in the tumor microenvironments.

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 in inflammation and allergy

We found for the first time that IL-4 and IL-13, signature type 2 cytokines, are able to induce periostin expression. We and others have subsequently shown that periostin is highly expressed in chronic inflammatory diseases-asthma, atopic dermatitis, eosinophilc chronic sinusitis/chronic rhinosinusitis with nasal polyp, and allergic conjunctivitis-and that periostin plays important roles in the pathogenesis of these diseases. The epithelial/mesenchymal interaction via periostin is important for the onset of allergic inflammation, in which periostin derived from fibroblasts acts on epithelial cells or fibroblasts, activating their NF-κB. Moreover, the immune cell/non-immune cell interaction via periostin may be also involved. Now the significance of periostin has been expanded into other inflammatory or fibrotic diseases such as scleroderma and pulmonary fibrosis. The cross-talk of periostin with TGF-β or pro-inflammatory cytokines is important for the underlying mechanism of these diseases. Because of its pathogenic importance and broad expression, diagnostics or therapeutic drugs can be potentially developed to target periostin as a means of treating these diseases.

Proteomic profiling of TGFBI-null mouse corneas reveals only minor changes in matrix composition supportive of TGFBI knockdown as therapy against TGFBI-linked corneal dystrophies

TGFBIp is a constituent of the extracellular matrix in many human tissues including the cornea, where it is one of the most abundant proteins expressed. TGFBIp interacts with Type I, II, IV, VI, and XII collagens as well as several members of the integrin family, suggesting it plays an important role in maintaining structural integrity and possibly corneal transparency as well. Significantly, more than 60 point mutations within the TGFBI gene have been reported to result in aberrant TGFBIp folding and aggregation in the cornea, resulting in severe visual impairment and blindness. Several studies have focused on targeting TGFBIp in the cornea as a therapeutic approach to treat TGFBI-linked corneal dystrophies, but the effect of this approach on corneal homeostasis and matrix integrity remained unknown. In the current study, we evaluated the histological and proteomic profiles of corneas from TGFBI-deficient mice as well as potential redundant functions of the paralogous protein POSTN. The absence of TGFBIp in mouse corneas did not grossly affect the collagen scaffold, and POSTN is unable to compensate for loss of TGFBIp. Proteomic comparison of wild-type and TGFBI^-/- mice revealed 11 proteins were differentially regulated, including Type VI and XII collagens. However, as these alterations did not manifest at the macroscopic and behavioral levels, these data support partial or complete TGFBI knockdown as a potential therapy against TGFBI-linked corneal dystrophies. Lastly, in situ hybridization verified TGFBI mRNA in the epithelial cells but not in other cell types, supportive of a therapy directed specifically at this lineage.

Transcriptional profiling validates involvement of extracellular matrix and proteinases genes in mouse gonad development

Extracellular matrix (ECM) plays an important scaffolding role in the establishment of organs structure during development. A great number of ECM components and enzymes (proteinases) regulating formation/degradation of ECM during organ remodeling have been identified. In order to study the role of ECM in the mouse gonad development, especially during sexual differentiation of the gonads when the structure of the testis and ovary becomes established, we performed a global analysis of transcriptome in three main cell types of developing gonad (supporting, interstitial/stromal and germ cells) using transgenic mice, cell sorting and microarray. The genes coding for ECM components were mostly expressed in two gonadal cell lines: supporting and interstitial/stromal cells. These two cell lines differed in the expression pattern of ECM components, which suggests that ECM components might be crucial for differentiation of gonad compartments (for example testis cords vs. interstitium in XY gonads). Collagens and proteoglycans coding genes were mainly expressed in the interstitium/stromal cells, while non-collagen glycoproteins and matricellular coding genes were expressed in both cell lines. We also analyzed the expression of genes encoding ECM enzymes that are secreted to the ECM where they remodel the scaffolding of developing organs. We found that the ECM enzyme genes were also mostly expressed in supporting and interstitial/stromal cells. In contrast to the somatic cells, the germ cells expressed only limited number of ECM components and enzymes. This suggests that the germ line cells do not participate, or play only a minor role, in the sculpting of the gonad structure via ECM synthesis and remodeling. Importantly, the supporting cells showed the sex-specific pattern of expression of ECM components. However, the pattern of expression of most ECM enzymes in the somatic and germ cells is independent on the sex of the gonad. Further studies are required to elucidate the exact roles of identified genes in sexual differentiation of the gonads.

Periostin function in communication with extracellular matrices

Periostin is a secretory protein with a multi-domain structure, comprising an amino-terminal cysteine-rich EMI domain, four internal FAS 1 domains, and a carboxyl-terminal hydrophilic domain. These adjacent domains bind to extracellular matrix proteins (type I collagen, fibronectin, tenascin-C, and laminin γ2), and BMP-1 that catalyzes crosslinking of type I collagen, and proteoglycans, which play a role in cell adhesion. The binding sites on periostin have been demonstrated to contribute to the mechanical strength of connective tissues, enhancing intermolecular interactions in close proximity and their assembly into extracellular matrix architectures, where periostin plays further essential roles in physiological maintenance and pathological progression. Furthermore, periostin also binds to Notch 1 and CCN3, which have functions in maintenance of stemness, thus opening up a new field of periostin action.

Hypoxia and Redox Signaling on Extracellular Matrix Remodeling: From Mechanisms to Pathological Implications

SIGNIFICANCE

The extracellular matrix (ECM) is an essential modulator of cell behavior that influences tissue organization. It has a strong relevance in homeostasis and translational implications for human disease. In addition to ECM structural proteins, matricellular proteins are important regulators of the ECM that are involved in a myriad of different pathologies. Recent Advances: Biochemical studies, animal models, and study of human diseases have contributed to the knowledge of molecular mechanisms involved in remodeling of the ECM, both in homeostasis and disease. Some of them might help in the development of new therapeutic strategies. This review aims to review what is known about some of the most studied matricellular proteins and their regulation by hypoxia and redox signaling, as well as the pathological implications of such regulation.

CRITICAL ISSUES

Matricellular proteins have complex regulatory functions and are modulated by hypoxia and redox signaling through diverse mechanisms, in some cases with controversial effects that can be cell or tissue specific and context dependent. Therefore, a better understanding of these regulatory processes would be of great benefit and will open new avenues of considerable therapeutic potential.

FUTURE DIRECTIONS

Characterizing the specific molecular mechanisms that modulate matricellular proteins in pathological processes that involve hypoxia and redox signaling warrants additional consideration to harness the potential therapeutic value of these regulatory proteins. Antioxid. Redox Signal. 27, 802-822.

Sex differences in tendon structure and function

Tendons play a critical role in the transmission of forces between muscles and bones, and chronic tendon injuries and diseases are among the leading causes of musculoskeletal disability. Little is known about sex-based differences in tendon structure and function. Our objective was to evaluate the mechanical properties, biochemical composition, transcriptome, and cellular activity of plantarflexor tendons from 4 month old male and female C57BL/6 mice using in vitro biomechanics, mass spectrometry-based proteomics, genome-wide expression profiling, and cell culture techniques. While the Achilles tendons of male mice were approximately 6% larger than female mice (p < 0.05), the cell density of female mice was around 19% greater than males (p < 0.05). No significant differences in mechanical properties (p > 0.05) of plantaris tendons were observed. Mass spectrometry proteomics analysis revealed no significant difference between sexes in the abundance of major extracellular matrix (ECM) proteins such as collagen types I (p = 0.30) and III (p = 0.68), but female mice had approximately twofold elevations (p < 0.05) in less abundant ECM proteins such as fibronectin, periostin, and tenascin C. The transcriptome of male and female tendons differed by only 1%. In vitro, neither the sex of the serum that fibroblasts were cultured in, nor the sex of the ECM in which they were embedded, had profound effects on the expression of collagen and cell proliferation genes. Our results indicate that while male mice expectedly had larger tendons, male and female tendons have very similar mechanical properties and biochemical composition, with small increases in some ECM proteins and proteoglycans evident in female tendons. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2117-2126, 2017.

Deficiency of periostin impairs liver regeneration in mice after partial hepatectomy

Periostin (Postn) is a crucial extracellular remodeling factor that has been implicated in the pathogenesis of hepatic inflammation, fibrosis, non-alcoholic fatty liver disease and liver cancer. However, the role of Postn in liver regeneration remains unclear. Here, we demonstrate that Postn mRNA and protein levels are significantly upregulated in the mice after 2/3 partial hepatectomy (PHx). Compared with wild-type mice, Postn-deficient mice exhibit lower liver/body weight ratio and less Ki67-positive cells at days 2, 8 and 14 after PHx. Macrophage infiltration and the levels of TNF-α, IL-6 and HGF in the livers of Postn-deficient mice are significantly decreased compared with wild-type mice one day after PHx. In addition, overexpression of Postn leads to higher liver/body weight ratio and more Ki67-positive cells in the livers of mice and promotes hepatocyte proliferation in vitro. Moreover, liver sinusoidal endothelial cells, biliary epithelial cells and hepatocytes can express Postn after PHx, and Postn deficiency impairs angiogenesis during liver regeneration. Our findings indicate that Postn deficiency impairs liver regeneration in mice after PHx and Postn might be a novel promoter for liver regeneration.

miR-599 inhibits proliferation and invasion of glioma by targeting periostin

OBJECTIVE

To explore the molecular mechanism of microRNA-599(miR-599) in the migration and invasion of glioma.

RESULT

Clinicopathological characteristics of 33 patients were analyzed. Based on reverse transcription-PCR, miR-599 was down-regulated in glioma tissues compared with adjacent normal brain tissues (P < 0.001). Moreover, negative correlations between miR-599 and periostin protein expression in glioma tissues (P < 0.01) and necrosis by magnetic resonance imaging (P < 0.05) were observed. Transwell and wound healing assays showed that overexpression of miR-599 inhibited glioma cell migration and invasion. miR-599 down-regulated periostin expression by targeting the 3'-untranslated region. Additionally, re-expression of periostin partial reversed the suppressive effect of miR-599 on migration and invasion in vitro and in vivo.

CONCLUSION

microRNA-599 inhibits proliferation and invasion by down-regulating periostin expression in vitro and in vivo.

The Role of Periostin in the Occurrence and Progression of Eosinophilic Chronic Sinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a highly heterogeneous disease with different host defence responses. However, whether periostin and vascular endothelial growth factor (VEGF) are similarly impaired in patients with eosinophilic CRSwNP (ENP) and those with non-eosinophilic CRSwNP (nENP) remains unclear. We sought to evaluate the expression and possible modulation of periostin and VEGF, regulated on activation normal T expressed and secreted (RANTES) and eotaxin-2 in the polyp tissues from 30 patients with ENP and from 36 patients with nENP and in middle turbinate tissues from 12 control subjects. We found that ENP tissues exhibited a significantly increased expression of periostin and VEGF compared with tissues from patients with nENP and control subjects (P < 0.05, respectively). Accordingly, the expression of VEGF, RANTES, and eotaxin-2 in ENP fibroblasts was significantly up-regulated after stimulation with up-regulated periostin in vitro, but the expression of VEGF and RANTES was significantly inhibited by stimulation with down-regulated periostin. Our findings suggest that periostin might play an important role in the occurrence and progression of ENP and might be a potential therapeutic target.

Potential Biomarkers for NSAID-Exacerbated Respiratory Disease

Asthma is a common chronic disease with several variant phenotypes and endotypes. NSAID-exacerbated respiratory disease (NERD) is one such endotype characterized by asthma, chronic rhinosinusitis (CRS) with nasal polyps, and hypersensitivity to aspirin/cyclooxygenase-1 inhibitors. NERD is more associated with severe asthma than other asthma phenotypes. Regarding diagnosis, aspirin challenge tests via the oral or bronchial route are a standard diagnostic method; reliable in vitro diagnostic tests are not available. Recent studies have reported various biomarkers of phenotype, diagnosis, and prognosis. In this review, we summarized the known potential biomarkers of NERD that are distinct from those of aspirin-tolerant asthma. We also provided an overview of the different NERD subgroups.

Circulating periostin levels increase in association with bone density loss and healing progression during the early phase of hip fracture in Chinese older women

The present study shows that hip fracture women had higher serum periostin (sPostn) levels. The elevation of sPostn is associated with bone density loss, yet fracture itself may even increase sPostn levels during early healing phase.

INTRODUCTION

The study aims to quantify the associations of sPostn levels with bone density loss and the possible effect on the fracture healing.

METHODS

This study enrolled 261 older women with osteoporotic hip fracture and 106 age-matched women without fracture serving as controls. Clinical features, bone mineral density (BMD), and bone turnover markers including sPostn level were measured after fracture within 2 days. Follow-up sPostn levels during 1 year after 2 days were available for 128 patients.

RESULTS

Initial levels of sPostn after fracture were significantly higher in patients than controls. sPostn was correlated with BMD of femoral neck (r = -0.529, P < 0.001), β-isomerized C-terminal crosslinking of type I collagen (β-CTX) (r = 0.403, P = 0.008), and N-terminal procollagen of type I collagen (PINP) (r = 0.236, P = 0.042) in the entire cohort. After multivariate analysis, sPostn remained as an independent risk factor for femoral neck BMD, which explained 19.1% of the variance in BMD. sPostn sampled within 7 days after fracture were acutely increasing from day 2 and then decreased and maintained at slightly high levels at 360 days. The percentage changes of sPostn positively correlated with the variation in β-CTX (r = 0.396, P = 0.002) and PINP (r = 0.180, P = 0.033) at day 7 after fracture.

CONCLUSIONS

High sPostn levels were an independent predictor of femoral neck BMD in older women presenting with an acute hip fracture. Increased sPostn levels during early healing phase may imply that Postn play a role in bone repair.

TGFBI functions similar to periostin but is uniquely dispensable during cardiac injury

Extracellular matrix production and accumulation stabilize the heart under normal conditions as well as form a protective scar after myocardial infarction injury, although excessive extracellular matrix accumulation with long-standing heart disease is pathological. In the current study we investigate the role of the matricellular protein, transforming growth factor beta-induced (TGFBI), which is induced in various forms of heart disease. Additionally, we sought to understand whether TGFBI is functionally redundant to its closely related family member periostin, which is also induced in the diseased heart. Surgical models of myocardial infarction and cardiac pressure overload were used in mice with genetic loss of Postn and/or Tgfbi to examine the roles of these genes during the fibrotic response. Additionally, cardiac-specific TGFBI transgenic mice were generated and analyzed. We observed that deletion of Tgfbi did not alter cardiac disease after myocardial infarction in contrast to greater ventricular wall rupture in Postn gene-deleted mice. Moreover, Tgfbi and Postn double gene-deleted mice showed a similar post-myocardial infarction disease phenotype as Postn-deleted mice. Over-expression of TGFBI in the hearts of mice had a similar effect as previously shown in mice with periostin over-expression. Thus, TGFBI and periostin act similarly in the heart in affecting fibrosis and disease responsiveness, although TGFBI is not seemingly necessary in the heart after myocardial infarction injury and is fully compensated by the more prominently expressed effector periostin.

Roles of Periostin in Respiratory Disorders

Periostin is a matricellular protein that has been implicated in many disease states. It interacts with multiple signaling cascades to modulate the expression of downstream genes that regulate cellular interactions within the extracellular matrix. This review focuses on the role of periostin in respiratory diseases, including asthma and idiopathic pulmonary fibrosis, and its potential to help guide treatment or assess prognosis. Epithelial injury is a common feature of many respiratory diseases, resulting in the secretion, among others, of periostin, which is subsequently involved in airway remodeling and other aspects of pulmonary pathophysiology. In asthma, periostin is recognized as a biomarker of type 2 inflammation; POSTN gene expression is up-regulated in bronchial epithelial cells by IL-13 and IL-4. Serum periostin has been evaluated for the identification of patients with increased clinical benefit from treatment with anti-IL-13 (lebrikizumab, tralokinumab) and anti-IgE (omalizumab) therapy and may be prognostic for increased risk of asthma exacerbations and progressive lung function decline. Furthermore, in asthma, periostin may regulate subepithelial fibrosis and mucus production and may serve as a systemic biomarker of eosinophilic airway inflammation. Periostin is also highly expressed in the lungs of patients with idiopathic pulmonary fibrosis, and its serum levels may predict clinical progression. Overall, periostin contributes to multiple pathogenic processes across respiratory diseases, and peripheral blood levels of periostin may have utility as a biomarker of treatment response and disease progression.

Immune biomarkers in the spectrum of childhood noncommunicable diseases

A biomarker is an accurately and reproducibly quantifiable biological characteristic that provides an objective measure of health status or disease. Benefits of biomarkers include identification of therapeutic targets, monitoring of clinical interventions, and development of personalized (or precision) medicine. Challenges to the use of biomarkers include optimizing sample collection, processing and storage, validation, and often the need for sophisticated laboratory and bioinformatics approaches. Biomarkers offer better understanding of disease processes and should benefit the early detection, treatment, and management of multiple noncommunicable diseases (NCDs). This review will consider the utility of biomarkers in patients with allergic and other immune-mediated diseases in childhood. Typically, biomarkers are used currently to provide mechanistic insight or an objective measure of disease severity, with their future role in risk stratification/disease prediction speculative at best. There are many lessons to be learned from the biomarker strategies used for cancer in which biomarkers are in routine clinical use and industry-wide standardized approaches have been developed. Biomarker discovery and validation in children with disease lag behind those in adults; given the early onset and therefore potential lifelong effect of many NCDs, there should be more studies incorporating cohorts of children. Many pediatric biomarkers are at the discovery stage, with a long path to evaluation and clinical implementation. The ultimate challenge will be optimization of prevention strategies that can be implemented in children identified as being at risk of an NCD through the use of biomarkers.

Biomarkers in asthmatic patients: Has their time come to direct treatment?

Asthma is a heterogeneous disease with multiple phenotypes that have variable risk factors and responses to therapeutics. Mild-to-moderate asthma often responds to traditional medications, whereas severe disease can be refractory to inhaled corticosteroids, long-acting β-agonists, and leukotriene receptor antagonists. There is robust research into the variable phenotypes of asthma. Biomarkers help define the specific pathophysiology of different asthma phenotypes and identify potential therapeutic targets. The following review will discuss the current use of biomarkers for the diagnosis of asthma, triaging the severity of a patient's disease, and the potential efficacy of treatments. This information can be used to define certain patient populations that are more likely to respond to inhaled corticosteroids or biologics. As knowledge of patient phenotypes and endotypes and biological agents to target specific classes of asthma emerge, the ability to provide personalized care to asthmatic patients will follow.

Immune signatures of pathogenesis in the peritoneal compartment during early infection of sheep with Fasciola hepatica

Immune signatures of sheep acutely-infected with Fasciola hepatica, an important pathogen of livestock and humans were analysed within the peritoneal compartment to investigate early infection. Within the peritoneum, F. hepatica antibodies coincided with an intense innate and adaptive cellular immune response, with infiltrating leukocytes and a marked eosinophilia (49%). However, while cytokine qPCR analysis revealed IL-10, IL-12, IL-13, IL-23 and TGFβ were elevated, these were not statistically different at 18 days post-infection compared to uninfected animals indicating that the immune response is muted and not yet skewed to a Th2 type response that is associated with chronic disease. Proteomic analysis of the peritoneal fluid identified infection-related proteins, including several structural proteins derived from the liver extracellular matrix, connective tissue and epithelium, and proteins related to the immune system. Periostin and vascular cell adhesion protein 1 (VCAM-1), molecules that mediate leukocyte infiltration and are associated with inflammatory disorders involving marked eosinophilia (e.g. asthma), were particularly elevated in the peritoneum. Immuno-histochemical studies indicated that the source of periostin and VCAM-1 was the inflamed sheep liver tissue. This study has revealed previously unknown aspects of the immunology and pathogenesis associated with acute fascioliasis in the peritoneum and liver.

Characterization of a sandwich ELISA for the quantification of all human periostin isoforms

BACKGROUND

Periostin (osteoblast-specific factor OSF-2) is a secreted protein occurring in seven known isoforms, and it is involved in a variety of biological processes in osteology, tissue repair, oncology, cardiovascular and respiratory systems or allergic manifestations. To analyze functional aspects of periostin, or the ability of periostin as potential biomarker in physiological and pathological conditions, there is the need for a precise, well-characterized assay that detects periostin in peripheral blood.

METHODS

In this study the development of a sandwich ELISA using monoclonal and affinity-purified polyclonal anti-human periostin antibodies was described. Antibodies were characterized by mapping of linear epitopes with microarray technology, and by analyzing cross-reactive binding to human periostin isoforms with western blot. The assay was validated according to ICH/EMEA guidelines.

RESULTS

The monoclonal coating antibody binds to a linear epitope conserved between the isoforms. The polyclonal detection antibody recognizes multiple conserved linear epitopes. Therefore, the periostin ELISA detects all known human periostin isoforms. The assay is optimized for human serum and plasma and covers a calibration range between 125 and 4000 pmol/L for isoform 1. Assay characteristics, such as precision (intra-assay: ≤3%, inter-assay: ≤6%), spike-recovery (83%-106%), dilution linearity (95%-126%), as well as sample stability meet the standards of acceptance. Periostin levels of apparently healthy individuals are 864±269 pmol/L (serum) and 817±170 pmol/L (plasma) respectively.

CONCLUSION

This ELISA is a reliable and accurate tool for determination of all currently known periostin isoforms in human healthy and diseased samples.

IL-5-stimulated eosinophils adherent to periostin undergo stereotypic morphological changes and ADAM8-dependent migration

BACKGROUND

IL-5 causes suspended eosinophils to polarize with filamentous (F)-actin and granules at one pole and the nucleus in a specialized uropod, the "nucleopod," which is capped with P-selectin glycoprotein ligand-1 (PSGL-1). IL-5 enhances eosinophil adhesion and migration on periostin, an extracellular matrix protein upregulated in asthma by type 2 immunity mediators.

OBJECTIVE

Determine how the polarized morphology evolves to foster migration of IL-5-stimulated eosinophils on a surface coated with periostin.

METHODS

Blood eosinophils adhering to adsorbed periostin were imaged at different time points by fluorescent microscopy, and migration of eosinophils on periostin was assayed.

RESULTS

After 10 minutes in the presence of IL-5, adherent eosinophils were polarized with PSGL-1 at the nucleopod tip and F-actin distributed diffusely at the opposite end. After 30-60 minutes, the nucleopod had dissipated such that PSGL-1 was localized in a crescent or ring away from the cell periphery, and F-actin was found in podosome-like structures. The periostin layer, detected with monoclonal antibody Stiny-1, shown here to recognize the FAS1 4 module, was cleared in wide areas around adherent eosinophils. Clearance was attenuated by metalloproteinase inhibitors or antibodies to disintegrin metalloproteinase 8 (ADAM8), a major eosinophil metalloproteinase previously implicated in asthma pathogenesis. ADAM8 was not found in podosome-like structures, which are associated with proteolytic activity in other cell types. Instead, immunoblotting demonstrated proteoforms of ADAM8 that lack the cytoplasmic tail in the supernatant. Anti-ADAM8 inhibited migration of IL-5-stimulated eosinophils on periostin.

CONCLUSIONS AND CLINICAL RELEVANCE

Migrating IL-5-activated eosinophils on periostin exhibit loss of nucleopodal features and appearance of prominent podosomes along with clearance of the Stiny-1 periostin epitope. Migration and epitope clearance are both attenuated by inhibitors of ADAM8. We propose, therefore, that eosinophils remodel and migrate on periostin-rich extracellular matrix in the asthmatic airway in an ADAM8-dependent manner, making ADAM8 a possible therapeutic target.

Influence of Periostin on Synoviocytes in Knee Osteoarthritis

BACKGROUND

Periostin (POSTN) is a protein that binds to integrins to support adhesion and migration of epithelial cells. Mice lacking this gene exhibit cardiac valve disease as well as skeletal and dental defects. Recent studies indicated that periostin is involved in the pathogenesis and progression of knee osteoarthritis (OA). We investigated the influence of periostin and matrix metalloproteinases (MMPs) on OA synoviocytes.

MATERIALS AND METHODS

OA patients were classified according to the Kellgren-Lawrence system and the levels of periostin, interleukin (IL)-4, IL-13 and transforming growth factor-β (TGFβ) in the synovial fluid were measured. MMPs or tissue inhibitor of MMPs (TIMPs) with periostin in cultured cells were measured when periostin was added to OA-associated synovial cells. Dexamethasone, a steroid medication which shows immunosuppressive effects, was used to investigate the influence of the downstream cascade.

RESULTS

Periostin and IL-13 levels were up-regulated during the progression of OA. MMP-2 and MMP-3 levels increased in a periostin concentration-dependent manner. Increase in MMP-2 and MMP-3 levels was inhibited by dexamethasone treatment.

CONCLUSION

In vivo results herein indicate that IL-13 may induce periostin production in OA. Furthermore, periostin may facilitate MMP production in OA-associated synovial cells.