Pathological Roles and Clinical Usefulness of Periostin in Type 2 Inflammation and Pulmonary Fibrosis

The nasal basal cell population shifts toward a diseased phenotype with impaired barrier formation capacity in allergic rhinitis

BACKGROUND

The integrity of the airway epithelium is guarded by the airway basal cells that serve as progenitor cells and restore wounds in case of injury. Basal cells are a heterogenous population, and specific changes in their behavior are associated with chronic barrier disruption-mechanisms that have not been studied in detail in allergic rhinitis (AR).

OBJECTIVE

We aimed to study basal cell subtypes in AR and healthy controls.

METHODS

Single-cell RNA sequencing (scRNA-Seq) of the nasal epithelium was performed on nonallergic and house dust mite-allergic AR patients to reveal basal cell diversity and to identify allergy-related alterations. Flow cytometry, immunofluorescence staining, and in vitro experiments using primary basal cells were performed to confirm phenotypic findings at the protein level and functionally.

RESULTS

The scRNA-Seq, flow cytometry, and immunofluorescence staining revealed that basal cells are abundantly and heterogeneously present in the nasal epithelium, suggesting specialized subtypes. The total basal cell fraction within the epithelium in AR is increased compared to controls. scRNA-Seq demonstrated that potentially beneficial basal cells are missing in AR epithelium, while an activated population of allergy-associated basal cells is more dominantly present. Furthermore, our in vitro proliferation, wound healing assay and air-liquid interface cultures show that AR-associated basal cells have altered progenitor capacity compared to nonallergic basal cells.

CONCLUSIONS

The nasal basal cell population is abundant and diverse, and it shifts toward a diseased state in AR. The absence of potentially protective subtypes and the rise of a proinflammatory population suggest that basal cells are important players in maintaining epithelial barrier defects in AR.

Periostin-TGF-β feedforward loop contributes to tumour-stroma crosstalk in liver metastatic outgrowth of colorectal cancer

BACKGROUND

This study aimed to investigate the underlying mechanisms of matricellular protein periostin (POSTN) on tumour-stroma crosstalk in the liver metastatic microenvironment of colorectal cancer (CRC).

METHODS

Postn-knockout mice and hepatic Postn-overexpressing mice were used to investigate the functions of POSTN on the formation of fibrotic microenvironment and the tumour-stroma crosstalk in the liver metastatic microenvironment of CRC. Clinical samples and database were analyzed to show the correlation between POSTN expression and fibrotic features and TGF-β signalling in metastatic livers of CRC.

RESULTS

POSTN deficiency reduced hepatic stellate cell (HSC) activation and liver metastasis, whereas POSTN overexpression in the liver significantly augmented the formation of a fibrotic microenvironment to support the liver metastatic growth of CRC cells in mice. Moreover, HSC-derived POSTN promoted TGF-β1 expression in CRC cells through the integrin/FAK/ERK/STAT3 pathway; conversely, tumour cell-derived TGF-β1 induced POSTN expression in HSCs via the Smad pathway. POSTN levels correlated with fibrotic features and TGF-β signalling in metastatic liver tissues of CRC patients.

CONCLUSIONS

POSTN and TGF-β1 cooperatively contribute to the tumour-stroma crosstalk by forming a supporting fibrotic microenvironment to promote liver metastasis of CRC cells via the POSTN/integrin/FAK/ERK/STAT3/TGF-β axis in tumour cells and TGF-β/Smad/POSTN signalling in activated HSCs.

Vernal keratoconjunctivitis: Current immunological and clinical evidence and the potential role of omalizumab

Vernal keratoconjunctivitis (VKC) is a severe ocular allergic disease characterized by chronic inflammation of the cornea and conjunctiva that may lead to loss of visual acuity and blindness. The disease occurs primarily in children and is more common in geographical regions characterized by warm temperatures and high humidity. The clinical manifestations of VKC, when inadequately treated, may lead to severe complications and corneal damage. The prevalence of allergen sensitization, specific serum immunoglobulin E (IgE), and specific tear IgE was reported in approximately 55%-60% of patients with VKC, confirming the involvement of IgE-mediated and non-IgE-mediated mechanisms in the pathophysiology of the condition. This article explores current knowledge on the immunological pathways of VKC and the role of the monoclonal anti-IgE antibody, omalizumab, in its management. The review evaluated the effects of omalizumab beyond the direct IgE-mediated reactions and discusses its potential as a therapeutic target for VKC. Multiple retrospective analyses, case series, and case reports have reported the effectiveness of omalizumab in the management of VKC. A summary of the clinical data from these studies revealed that in children with VKC omalizumab treatment was well tolerated with improvement or resolution of ocular symptoms, reduction in steroid use, and enhancement of quality of life. Omalizumab may serve as a promising treatment option for VKC due to its ability to target both IgE-mediated and non-IgE-mediated pathophysiological pathways. Larger, controlled clinical trials are needed to support these findings.

Specific Subtypes of Carcinoma-Associated Fibroblasts Are Correlated with Worse Survival in Resectable Pancreatic Ductal Adenocarcinoma

PURPOSE

The pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancer entities. Effective therapy options are still lacking. The tumor microenvironment possibly bears further treatment possibilities. This study aimed to describe the expression patterns of four established carcinoma-associated fibroblast (CAFs) markers and their correlation in PDAC tissue samples.

METHODS

This project included 321 patients with PDAC who underwent surgery with a curative intent in one of the PANCALYZE study centers. Immunohistochemical stainings for FAP, PDGFR, periostin, and SMA were performed. The expression patterns of each marker were divided into low- and high-expressing CAFs and correlated with patients' survival.

RESULTS

Tumors showing SMA^high-, Periostin^highSMA^high-, or Periostin^highSMA^lowPDGFR^lowFAP^high-positive CAFs demonstrated significantly worse survival. Additionally, a high expression of SMA in PDAC tissue samples was shown to be an independent risk factor for worse survival.

CONCLUSION

This project identified three subgroups of PDAC with different expression patterns of CAF markers which showed significantly worse survival. This could be the base for the further characterization of the fibroblast subgroups in PDAC and contribute to the development of new targeted therapy options against CAFs.

IL13 and periostin in active fibrogenic areas of the extrahepatic bile ducts in biliary atresia patients

BACKGROUND

The leading pathology of biliary atresia (BA) is inflammatory and fibrous obstruction of extrahepatic bile duct, but the pathogenesis remains unclear. IL13 is a cytokine associated with allergies and inflammatory fibrosis, and periostin induces fibrogenesis by stimulation with IL13. We analyzed the involvement of IL13 and periostin in inflammatory fibrosis in the extrahepatic bile duct of BA patients.

MATERIALS AND METHODS

Surgically resected tissues from the hepatic hilar area of BA patients were immunostained with CD45, α-SMA, IL13 and periostin and statistically analyzed. Fibroblasts from the resected tissue were cultured with recombinant IL13, and periostin production was analyzed by quantitative polymerase chain reaction and Western blotting.

RESULTS

IL13 was stained in 93% of large and micro bile ducts, and 92.1% matched with the CD45 location (p = 0.006) around the large bile ducts. Periostin staining correlated with the localization of IL13 and αSMA (p < 0.001) around the large bile ducts. Periostin mRNA and protein were upregulated by IL13 stimulation in cultured fibroblasts.

CONCLUSION

IL13 was associated with induced periostin expression by fibroblasts, playing a vital role in the pathogenesis of fibrogenesis around the extrahepatic bile duct in BA.

In vitro models for investigating itch

Itch (pruritus) is a sensation that drives a desire to scratch, a behavior observed in many animals. Although generally short-lasting and not causing harm, there are several pathological conditions where chronic itch is a hallmark symptom and in which prolonged scratching can induce damage. Finding medications to counteract the sensation of chronic itch has proven difficult due to the molecular complexity that involves a multitude of triggers, receptors and signaling pathways between skin, immune and nerve cells. While much has been learned about pruritus from in vivo animal models, they have limitations that corroborate the necessity for a transition to more human disease-like models. Also, reducing animal use should be encouraged in research. However, conducting human in vivo experiments can also be ethically challenging. Thus, there is a clear need for surrogate models to be used in pre-clinical investigation of the mechanisms of itch. Most in vitro models used for itch research focus on the use of known pruritogens. For this, sensory neurons and different types of skin and/or immune cells are stimulated in 2D or 3D co-culture, and factors such as neurotransmitter or cytokine release can be measured. There are however limitations of such simplistic in vitro models. For example, not all naturally occurring cell types are present and there is also no connection to the itch-sensing organ, the central nervous system (CNS). Nevertheless, in vitro models offer a chance to investigate otherwise inaccessible specific cell–cell interactions and molecular pathways. In recent years, stem cell-based approaches and human primary cells have emerged as viable alternatives to standard cell lines or animal tissue. As in vitro models have increased in their complexity, further opportunities for more elaborated means of investigating itch have been developed. In this review, we introduce the latest concepts of itch and discuss the advantages and limitations of current in vitro models, which provide valuable contributions to pruritus research and might help to meet the unmet clinical need for more refined anti-pruritic substances.

Can serum periostin predict bronchopulmonary dysplasia in premature infants?

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common morbidity complicating preterm birth and affects long-term respiratory outcomes. The objectives of this study were to establish whether serum periostin at birth, day of life (DOL) 28, and corrected 36 weeks' gestational age could be potential biomarkers for BPD.

METHODS

A total of 98 preterm Japanese infants born at <32 weeks and comparing 41 healthy controls born at term, were divided into BPD (n = 44) and non-BPD (n = 54) cohorts. Serum periostin levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Among 98 preterm infants, the median serum periostin levels at birth were higher with BPD (338.0 ng/mL) than without (275.0 ng/mL, P < 0.001). Multivariate analysis revealed that serum periostin levels at birth were significantly associated with BPD (P = 0.013). Serum periostin levels at birth with moderate/severe BPD (345.0 ng/mL) were significantly higher than those with non-BPD/mild BPD (283.0 ng/mL, P = 0.006).

CONCLUSIONS

Serum periostin levels were significantly correlated with birth weight and gestational age, and serum periostin levels at birth in BPD infants were significantly higher than that in non-BPD infants.

IMPACT

This study found higher serum periostin levels at birth in preterm infants subsequently diagnosed with bronchopulmonary dysplasia. It also emerged that serum periostin levels at birth significantly correlated with gestational age and birth weight. The mechanism by which serum periostin is upregulated in BPD infants needs further investigation.