Angiogenesis Dysregulation in Psoriatic Arthritis: Molecular Mechanisms

IL-36γ Augments Ocular Angiogenesis by Promoting the Vascular Endothelial Growth Factor-Vascular Endothelial Growth Factor Receptor Axis

Prevention of inflammatory angiogenesis is critical for suppressing chronic inflammation and inhibiting inflammatory tissue damage. Angiogenesis is particularly detrimental to the cornea because pathologic growth of new blood vessels can lead to marked vision impairment and even loss of vision. The expression of proinflammatory cytokines by injured tissues exacerbates the inflammatory cascade, including angiogenesis. IL-36 cytokine, a subfamily of the IL-1 superfamily, consists of three proinflammatory agonists, IL-36α, IL-36β, and IL-36γ, and an IL-36 receptor antagonist (IL-36Ra). Data from the current study indicate that human vascular endothelial cells constitutively expressed the cognate IL-36 receptor. The current investigation, for the first time, characterized the direct contribution of IL-36γ to various angiogenic processes. IL-36γ up-regulated the expression of vascular endothelial growth factors (VEGFs) and their receptors VEGFR2 and VEGFR3 by human vascular endothelial cells, suggesting that IL-36γ mediates the VEGF-VEGFR signaling by endothelial cells. Moreover, by using a naturally occurring antagonist IL-36Ra in a murine model of inflammatory angiogenesis, this study demonstrated that blockade of endogenous IL-36γ signaling results in significant retardation of inflammatory angiogenesis. The current investigation on the proangiogenic function of IL-36γ provides novel evidence of the development of IL-36γ-targeting strategies to hamper inflammatory angiogenesis.

Application of clinical and molecular profiling data to improve patient outcomes in psoriatic arthritis

Achieving a good outcome for a person with Psoriatic Arthritis (PsA) is made difficult by late diagnosis, heterogenous clinical disease expression and in many cases, failure to adequately suppress inflammatory disease features. Single-centre studies have certainly contributed to our understanding of disease pathogenesis, but to adequately address the major areas of unmet need, multi-partner, collaborative research programmes are now required. HIPPOCRATES is a 5-year, Innovative Medicines Initiative (IMI) programme which includes 17 European academic centres experienced in PsA research, 5 pharmaceutical industry partners, 3 small-/medium-sized industry partners and 2 patient-representative organizations. In this review, the ambitious programme of work to be undertaken by HIPPOCRATES is outlined and common approaches and challenges are identified. It is expected that, when completed, the results will ultimately allow for changes in the approaches to diagnosing, managing and treating PsA allowing for better short-term and long-term outcomes.

Computational approaches in rheumatic diseases - Deciphering complex spatio-temporal cell interactions

Inflammatory arthritis, including rheumatoid (RA), and psoriatic (PsA) arthritis, are clinically and immunologically heterogeneous diseases with no identified cure. Chronic inflammation of the synovial tissue ushers loss of function of the joint that severely impacts the patient's quality of life, eventually leading to disability and life-threatening comorbidities. The pathogenesis of synovial inflammation is the consequence of compounded immune and stromal cell interactions influenced by genetic and environmental factors. Deciphering the complexity of the synovial cellular landscape has accelerated primarily due to the utilisation of bulk and single cell RNA sequencing. Particularly the capacity to generate cell-cell interaction networks could reveal evidence of previously unappreciated processes leading to disease. However, there is currently a lack of universal nomenclature as a result of varied experimental and technological approaches that discombobulates the study of synovial inflammation. While spatial transcriptomic analysis that combines anatomical information with transcriptomic data of synovial tissue biopsies promises to provide more insights into disease pathogenesis, in vitro functional assays with single-cell resolution will be required to validate current bioinformatic applications. In order to provide a comprehensive approach and translate experimental data to clinical practice, a combination of clinical and molecular data with machine learning has the potential to enhance patient stratification and identify individuals at risk of arthritis that would benefit from early therapeutic intervention. This review aims to provide a comprehensive understanding of the effect of computational approaches in deciphering synovial inflammation pathogenesis and discuss the impact that further experimental and novel computational tools may have on therapeutic target identification and drug development.

Identification of Novel Loci Shared by Juvenile Idiopathic Arthritis Subtypes through Integrative Genetic Analysis

Objective

Juvenile idiopathic arthritis (JIA) is the most common chronic immune‐mediated joint disease among children and encompasses a heterogeneous group of immune‐mediated joint disorders classified into 7 subtypes according to clinical presentation. However, phenotype overlap and biologic evidence suggest a shared mechanistic basis between subtypes. This study was undertaken to systematically investigate shared genetic underpinnings of JIA subtypes.

Methods

We performed a heterogeneity‐sensitive genome‐wide association study encompassing a total of 1,245 JIA cases (classified into 7 subtypes) and 9,250 controls, followed by fine‐mapping of candidate causal variants at each genome‐wide significant locus, functional annotation, and pathway and network analysis. We further identified candidate drug targets and drug repurposing opportunities by in silico analyses.

Results

In addition to the major histocompatibility complex locus, we identified 15 genome‐wide significant loci shared between at least 2 JIA subtypes, including 10 novel loci. Functional annotation indicated that candidate genes at these loci were expressed in diverse immune cell types.

Conclusion

This study identified novel genetic loci shared by JIA subtypes. Our findings identified candidate mechanisms underlying JIA subtypes and candidate targets with drug repurposing opportunities for JIA treatment.

Multispectral optoacoustic tomography might be a helpful tool for noninvasive early diagnosis of psoriatic arthritis

Currently used imaging methods for diagnosis of psoriatic arthritis (PsA) frequently come along with exposure to radiation and can often only show long-term effects of the disease. The aim of the study was to check the feasibility of a new optoacoustic imaging method to identify PsA. 22 psoriasis patients and 19 healthy volunteers underwent examination using multispectral optoacoustic tomography (MSOT). The presence of arthritis was assessed via quantification of optoacoustic signal intensity of the endogenous chromophores oxy- and deoxyhemoglobin. We conducted high-resolution real-time ultrasound images of the finger joints. The semi quantitative analysis of the optoacoustic signals for both hemoglobin species showed a significant higher blood content and oxygenation in PsA patients compared to healthy controls. Our results indicate that MSOT might allow detection of inflammation in an early stage. If the data is further confirmed, this technique might be a suitable tool to avoid delay of diagnosis of PsA.

Psoriatic mesenchymal stem cells stimulate the angiogenesis of human umbilical vein endothelial cells in vitro

OBJECTIVE

To investigate the regulation of psoriatic dermal mesenchymal stem cells (p-DMSCs) in the expression of vascular growth factor (VEGF), and migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro.

METHODS

A co-culture model of HUVECs and dermal mesenchymal stem cells (DMSCs)was used in this study. After 7-day co-culture, changes in expression levels of VEGF mRNA and protein in HUVECs were assessed using RT-PCR and Western Blotting, respectively. Migration and tubular formation of HUVECs were also assessed following co-culture of DMSCs and HUVECs.

RESULTS

In comparison to either HUVECs alone or co-culture of n-DMSCs and HUVECs, co-culture of HUVECs and p-DMSCs significantly increased expression levels of both VEGF mRNA (p < 0.01 vs. HUVECs alone) and protein in HUVECs (p < 0.001 vs. both HUVECs alone and HUVECs co-cultured with n-DMSCs). Moreover, p-DMSCs stimulated HUVEC migration and vascular formation (p < 0.05 vs. both HUVECs alone and co-culture of n-DMSCs and HUVECs).

CONCLUSION

Psoriatic DMSCs can upregulate VEGF expression, and stimulate migration and angiogenesis of HUVECs, suggesting a pathogenic role of p-DMSCs in psoriasis.

The IL-17/IL-23 Axis and Its Genetic Contribution to Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory disease belonging to the family of spondyloarthropathies (SpA). PsA commonly aggravates psoriasis of the skin and frequently manifests as an oligoarthritis with axial skeletal involvement and extraarticular manifestations including dactylitis, enthesitis, and uveitis. The weight of genetic predisposition to psoriasis and PsA is illustrated by the concordance rates in monozygotic twins which clearly demonstrate that genomics is insufficient to induce the clinical phenotype. The association of PsA with several single nucleotide polymorphisms (SNPs) at the IL23R locus and the involvement of Th17 cells in the immunopathogenesis of PsA clearly put the IL-23/IL-17 axis in the spotlight. The IL-23 and IL-17 cytokines have a pivotal role in the chronic inflammation of the synovium in PsA and are also prominent in the skin lesions of those with PsA. In this review, we focus on the genetic association of the IL-23/IL-17 axis with PsA and the contribution of these master cytokines in the pathophysiology of the disease, highlighting the main cell types incriminated in PsA and their specific role in the peripheral blood, lesional skin and joints of patients. We then provide an overview of the approved biologic drugs targeting the IL-23/IL-17 axis and discuss the advantages of genetic stratification to enhance personalized therapies in PsA.

The role of EMMPRIN/CD147 in regulating angiogenesis in patients with psoriatic arthritis

BACKGROUND

Angiogenesis plays a central role in the pathophysiology of rheumatic diseases. Patients with psoriatic arthritis (PsA) demonstrate increased vascularity over patients with rheumatoid arthritis (RA), with unknown mechanisms.

METHODS

We evaluated the serum levels of several pro- and anti-angiogenic factors in 62 PsA patients with active disease, 39 PsA patients in remission, 33 active RA patients, and 33 healthy controls (HC). Additionally, we used an in vitro co-culture system of fibroblast (HT1080) and monocytic-like (MM6) cell lines, to evaluate how their interactions affect the secretion of angiogenic factors and angiogenesis promoting abilities using scratch and tube formation assays.

RESULTS

PsA patients, regardless of disease activity, exhibited higher levels of EMMPRIN/CD147, IL-17, and TNF-α relative to RA patients or HC. Factors, such as IL-6, and the ratio between CD147 and thrombospondin-1, exhibited elevated levels in active PsA patients relative to PsA patients in remission. Secretion of CD147, VEGF, and MMP-9 was increased in vitro. CD147 neutralization with an antibody reduced these levels and the ability of endothelial cells to form tube-like structures or participate in wound healing.

CONCLUSIONS

CD147 plays a role in mediating angiogenesis in PsA, and the therapeutic possibilities of neutralizing it merit further investigation.

Innovative Imaging Technique for Visualization of Vascularization and Established Methods for Detection of Musculoskeletal Inflammation in Psoriasis Patients

Psoriasis (PsO) is one of the common chronic inflammatory skin diseases. Approximately 3% of the European Caucasian population is affected. Psoriatic arthritis (PsA) is a chronic immune-mediated disease associated with PsO characterized by distinct musculoskeletal inflammation. Due to its heterogeneous clinical manifestations (e.g., oligo- or polyarthritis, enthesitis, dactylitis, and axial inflammation), early diagnosis of PsA is often difficult and delayed. Approximately 30% of PsO patients will develop PsA. The responsible triggers for the transition from PsO only to PsA are currently unclear, and the impacts of different factors (e.g., genetic, environmental) on disease development are currently discussed. There is a high medical need, recently unmet, to specifically detect those patients with an increased risk for the development of clinically evident PsA early to initiate sufficient treatment to inhibit disease progression and avoid structural damage and loss of function or even intercept disease development. Increased neoangiogenesis and enthesial inflammation are hypothesized to be early pathological findings in PsO patients with PsA development. Different disease states describe the transition from PsO to PsA. Two of those phases are of value for early detection of PsA at-risk patients to prevent later development of PsA as changes in biomarker profiles are detectable: the subclinical phase (soluble and imaging biomarkers detectable, no clinical symptoms) and the prodromal phase (imaging biomarkers detectable, unspecific musculoskeletal symptoms such as arthralgia and fatigue). To target the unmet need for early detection of this at-risk population and to identify the subgroup of patients who will transition from PsO to PsA, imaging plays an important role in characterizing patients precisely. Imaging techniques such as ultrasound (US), magnetic resonance imaging (MRI), and computerized tomography (CT) are advanced techniques to detect sensitively inflammatory changes or changes in bone structure. With the use of these techniques, anatomic structures involved in inflammatory processes can be identified. These techniques are complemented by fluorescence optical imaging as a sensitive method for detection of changes in vascularization, especially in longitudinal measures. Moreover, high-resolution peripheral quantitative CT (HR-pQCT) and dynamic contrast-enhanced MRI (DCE-MRI) may give the advantage to identify PsA-related early characteristics in PsO patients reflecting transition phases of the disease.

IL-6 trans-Signaling Impairs Sprouting Angiogenesis by Inhibiting Migration, Proliferation and Tube Formation of Human Endothelial Cells

Sprouting angiogenesis is the formation of new capillaries from existing vessels in response to tissue hypoxia due to growth/development, repair/healing, and also chronic inflammation. In this study, we aimed to elucidate the effect of IL-6, a pleiotropic cytokine with both pro-inflammatory and anti-inflammatory functions, in regulating the sprouting angiogenic response of endothelial cells (ECs). We found that activation of IL-6 trans-signaling inhibited the migration, proliferation, and tube formation ability of ECs. In addition, inhibition of the autocrine IL-6 classic-signaling by depleting endogenous IL-6 from ECs impaired their tube formation ability. At the molecular level, we found that IL-6 trans-signaling in ECs upregulated established endogenous anti-angiogenic factors such as CXCL10 and SERPINF1 while at the same time downregulated known endogenous pro-angiogenic factors such as cKIT and CXCL8. Furthermore, prior activation of ECs by IL-6 trans-signaling alters their response to vascular endothelial growth factor-A (VEGF-A), causing an increased p38, but decreased Erk1/2 phosphorylation. Collectively, our data demonstrated the dual facets of IL-6 in regulating the sprouting angiogenic function of ECs. In addition, we shed light on molecular mechanisms behind the IL-6 trans-signaling mediated impairment of endothelial sprouting angiogenic response.

Pathogenesis of psoriasis in the "omic" era. Part I. Epidemiology, clinical manifestation, immunological and neuroendocrine disturbances

Psoriasis is a common, chronic, inflammatory, immune-mediated skin disease affecting about 2% of the world's population. According to current knowledge, psoriasis is a complex disease that involves various genes and environmental factors, such as stress, injuries, infections and certain medications. The chronic inflammation of psoriasis lesions develops upon epidermal infiltration, activation, and expansion of type 1 and type 17 Th cells. Despite the enormous progress in understanding the mechanisms that cause psoriasis, the target cells and antigens that drive pathogenic T cell responses in psoriatic lesions are still unproven and the autoimmune basis of psoriasis still remains hypothetical. However, since the identification of the Th17 cell subset, the IL-23/Th17 immune axis has been considered a key driver of psoriatic inflammation, which has led to the development of biologic agents that target crucial elements of this pathway. Here we present the current understanding of various aspects in psoriasis pathogenesis.

Targeting Angiogenesis With Peptide Vaccines

Most cancer peptide vaccinations tested so far are capable of eliciting a strong immune response, but demonstrate poor clinical benefits. Since peptide vaccination is safe and well-tolerated, and several indications suggest that it has clear potential advantages over other modalities of treatment, it is important to investigate the reasons for these clinical failures. In this review, the current state of the art in targeting angiogenic proteins via peptide vaccines is presented, and the underlying reasons for both the successes and the failures are analyzed. The review highlights a number of areas critical for future success, including choice of target antigens, types of peptides used, delivery methods and use of proper adjuvants, and suggests ways to achieve better clinical results in the future.

ERK activating peptide, AES16-2M promotes wound healing through accelerating migration of keratinocytes

Wound healing is an important issue that influences quality of life, and the need for products associated with wound healing is growing annually. New materials and therapies for skin wounds are being continuously researched and developed in order to increase treatment efficacy. Here, we show that the peptide AES16-2M comprised of five short amino acid sequences (REGRT) demonstrates efficacy in wound healing. AES16-2M exerted more effective healing than the control in an acute wound model, and tissue regeneration was similar to that of normal tissue in AES16-2M-treated skin. We found that the increase in re-epithelialization by AES16-2M early in wound development was due to migration of keratinocytes; a scratch assay using a human keratinocyte cell line (HaCaT) also demonstrated effective wound closure by AES16-2M. The migration of keratinocytes effected by AES16-2M was promoted through ERK phosphorylation and blocked with U0126, an ERK inhibitor. Moreover, AES16-2M treatment stimulated human dermal fibroblast (HDF) migration as well as keratinocyte. Taken together, these results suggest that AES16-2M can be an effective therapeutic agent for wound healing by promoting migration of keratinocytes and fibroblasts via ERK phosphorylation.

Anti-angiogenic effects of biotechnological therapies in rheumatic diseases

Introduction

Angiogenesis plays a key role in the pathogenesis of numerous rheumatic diseases, such as rheumatoid arthritis, psoriatic arthritis, and vasculitides. Therefore, the inhibition of pathological angiogenesis may be considered a useful therapeutical approach in these rheumatic diseases.

Methods

This review article is based on a literature research about the role of biotechnological therapies in angiogenesis inhibition.

Results and conclusions

Several evidences have demonstrated a role for biotechnological therapies in angiogenesis inhibition. Nevertheless, further research and clinical trials are needed to better quantify the real impact of biotechnological therapies on pathological angiogenesis.