Neuropeptide Y receptor 1 is expressed by B and T lymphocytes and mast cells in infantile haemangiomas

A novel three-dimensional model of infantile haemangioma

BACKGROUND

Infantile haemangioma (IH) is vascular tumour in infants that exhibits rapid proliferation and angiogenesis followed by gradual involution. Ten per cent of cases are associated with disfiguring complications that require medical intervention with beta blockers, surgery or laser therapy.

OBJECTIVES

To improve our understanding of the disease mechanisms of IH with an in vitro three-dimensional model.

METHODS

We isolated and expanded CD31+ endothelial cells (HemECs) from patient-derived IH cell lines and grew them as spheroids in STEMdiffTM Endothelial Expansion Medium. The cells were then embedded in an extracellular matrix hydrogel with reduced growth factors to initiate angiogenic sprouting.

RESULTS

HemEC spheroids expressed CD31, glucose transporter 1, vascular endothelial growth factor receptor 2, CD44, vimentin and CD133 but not smooth muscle actin, indicating their similarity to immature IH blood vessels and their angiogenic potential. Proteomic analysis revealed similar homology in terms of protein expression in spheroids and IH tissue. The high-throughput application of the three-dimensional angiogenesis model was tested using propranolol to inhibit sprouting of spheroids with increased toxicity response.

CONCLUSIONS

This study reports the development of a three-dimensional model of IH that closely resembles the angiogenic features of IH for molecular analysis and drug screening.

Recent advances in understanding the molecular basis of infantile haemangioma development

Infantile haemangioma (IH) - the most common vascular tumour of infancy - is comprised of diverse cell types, including endothelial cells, pericytes, fibroblasts and immune cells. IH is characterized by rapid proliferation followed by slow involution over 1-10 years. Most lesions regress spontaneously, but up to 10% can be disfiguring, with complications that require further medical treatment. Recent research has revealed the biological characteristics of IH, highlighting the involvement of angiogenesis and vasculogenesis during tumour formation. Gene expression profiling has provided vital insights into the underlying biological processes, with some of the key IH-related pathways identified, including vascular endothelial growth factor, the renin-angiotensin-aldosterone system, hypoxia-inducible factor 1α, Notch, platelet-derived growth factor, phosphoinositide 3-kinase/Akt/mammalian target of rapamycin, Janus kinase/signal transducers and activators of transcription, fibroblast growth factor, peroxisome proliferator-activated receptor-γ and insulin-like growth factor. Further evidence suggests extracellular matrix factors and hormone receptors regulate IH progression. In this review, we explore the molecular mechanisms involved in the proliferating, plateau and involuting phases of IH, identifying differentially expressed genes, targeted proteins and key signalling pathways. This knowledge will increase the broader understanding of vascular development, tissue remodelling and angiogenesis.

Sensory neurons regulate stimulus-dependent humoral immunity in mouse models of bacterial infection and asthma

Sensory neurons sense pathogenic infiltration to drive innate immune responses, but their role in humoral immunity is unclear. Here, using mouse models of Streptococcus pneumoniae infection and Alternaria alternata asthma, we show that sensory neurons are required for B cell recruitment and antibody production. In response to S. pneumoniae, sensory neuron depletion increases bacterial burden and reduces B cell numbers, IgG release, and neutrophil stimulation. Meanwhile, during A. alternata-induced airway inflammation, sensory neuron depletion decreases B cell population sizes, IgE levels, and asthmatic characteristics. Mechanistically, during bacterial infection, sensory neurons preferentially release vasoactive intestinal polypeptide (VIP). In response to asthma, sensory neurons release substance P. Administration of VIP into sensory neuron-depleted mice suppresses bacterial burden, while VIPR1 deficiency increases infection. Similarly, exogenous substance P delivery aggravates asthma in sensory neuron-depleted mice, while substance P deficiency ameliorates asthma. Our data, thus demonstrate that sensory neurons release select neuropeptides which target B cells dependent on the immunogen.

Sensory neurons regulate stimulus-dependent humoral immunity

Sensory neurons sense pathogenic infiltration, serving to inform immune coordination of host defense. However, sensory neuron-immune interactions have been predominantly shown to drive innate immune responses. Humoral memory, whether protective or destructive, is acquired early in life - as demonstrated by both early exposure to streptococci and allergic disease onset. Our study further defines the role of sensory neuron influence on humoral immunity in the lung. Using a murine model of Streptococcus pneumonia pre-exposure and infection and a model of allergic asthma, we show that sensory neurons are required for B-cell and plasma cell recruitment and antibody production. In response to S. pneumoniae, sensory neuron depletion resulted in a larger bacterial burden, reduced B-cell populations, IgG release and neutrophil stimulation. Conversely, sensory neuron depletion reduced B-cell populations, IgE and asthmatic characteristics during allergen-induced airway inflammation. The sensory neuron neuropeptide released within each model differed. With bacterial infection, vasoactive intestinal polypeptide (VIP) was preferentially released, whereas substance P was released in response to asthma. Administration of VIP into sensory neuron-depleted mice suppressed bacterial burden and increased IgG levels, while VIP1R deficiency increased susceptibility to bacterial infection. Sensory neuron-depleted mice treated with substance P increased IgE and asthma, while substance P genetic ablation resulted in blunted IgE, similar to sensory neuron-depleted asthmatic mice. These data demonstrate that the immunogen differentially stimulates sensory neurons to release specific neuropeptides which specifically target B-cells. Targeting sensory neurons may provide an alternate treatment pathway for diseases involved with insufficient and/or aggravated humoral immunity.

Neuropeptide Y and its receptors in prostate cancer: associations with cancer invasiveness and perineural spread

PURPOSE

Neuropeptide Y (NPY) is a pleiotropic peptide, which is involved in many biological mechanisms important in regulation of cell growth and survival. The aim of this study was a comprehensive analysis of the NPY system in prostate pathology.

METHODS

The study was based on immunohistochemical analysis of NPY and its receptors, Y1R, Y2R and Y5R, in tissue samples from benign prostate (BP), primary prostate cancer (PCa) and PCa bone metastases. Tissue microarray (TMA) technique was employed, with analysis of multiple cores from each specimen. Intensity of the immunoreactivity and expression index (EI), as well as distribution of the immunostaining in neoplastic cells and stromal elements were evaluated. Perineural invasion (PNI) and extraprostatic extension (EPE) were areas of special interests. Moreover, a transwell migration assay on the LNCaP PCa cell line was used to assess the chemotactic properties of NPY.

RESULTS

Morphological analysis revealed homogeneous membrane and cytoplasmic pattern of NPY staining in cancer cells and its membrane localization with apical accentuation in BP glands. All elements of the NPY system were upregulated in pre-invasive prostate intraepithelial neoplasia, PCa and metastases. EI and staining intensity of NPY receptors were significantly higher in PCa then in BP with correlation between Y2R and Y5R. The strength of expression of the NPY system was further increased in the PNI and EPE areas. In bone metastases, Y1R and Y5R presented high expression scores.

CONCLUSION

The results of our study suggest that the NPY system is involved in PCa, starting from early stages of its development to disseminated states of the disease, and participates in the invasion of PCa into the auto and paracrine matter.

Neuropeptide Y Peptide Family and Cancer: Antitumor Therapeutic Strategies

Currently available data on the involvement of neuropeptide Y (NPY), peptide YY (PYY), and pancreatic polypeptide (PP) and their receptors (YRs) in cancer are updated. The structure and dynamics of YRs and their intracellular signaling pathways are also studied. The roles played by these peptides in 22 different cancer types are reviewed (e.g., breast cancer, colorectal cancer, Ewing sarcoma, liver cancer, melanoma, neuroblastoma, pancreatic cancer, pheochromocytoma, and prostate cancer). YRs could be used as cancer diagnostic markers and therapeutic targets. A high Y1R expression has been correlated with lymph node metastasis, advanced stages, and perineural invasion; an increased Y5R expression with survival and tumor growth; and a high serum NPY level with relapse, metastasis, and poor survival. YRs mediate tumor cell proliferation, migration, invasion, metastasis, and angiogenesis; YR antagonists block the previous actions and promote the death of cancer cells. NPY favors tumor cell growth, migration, and metastasis and promotes angiogenesis in some tumors (e.g., breast cancer, colorectal cancer, neuroblastoma, pancreatic cancer), whereas in others it exerts an antitumor effect (e.g., cholangiocarcinoma, Ewing sarcoma, liver cancer). PYY or its fragments block tumor cell growth, migration, and invasion in breast, colorectal, esophageal, liver, pancreatic, and prostate cancer. Current data show the peptidergic system's high potential for cancer diagnosis, treatment, and support using Y2R/Y5R antagonists and NPY or PYY agonists as promising antitumor therapeutic strategies. Some important research lines to be developed in the future will also be suggested.

Neuro-immune-metabolism: The tripod system of homeostasis

Homeostatic regulation of cellular and molecular processes is essential for the efficient physiological functioning of body organs. It requires an intricate balance of several networks throughout the body, most notable being the nervous, immune and metabolic systems. Several studies have reported the interactions between neuro-immune, immune-metabolic and neuro-metabolic pathways. Current review aims to integrate the information and show that neuro, immune and metabolic systems form the triumvirate of homeostasis. It focuses on the cellular and molecular interactions occurring in the extremities and intestine, which are innervated by the peripheral nervous system and for the intestine in particular the enteric nervous system. While the interdependence of neuro-immune-metabolic pathways provides a fallback mechanism in case of disruption of homeostasis, in chronic pathologies of continued disequilibrium, the collapse of one system spreads to the other interacting networks as well. Current review illustrates this domino-effect using diabetes as the main example. Together, this review attempts to provide a holistic picture of the integrated network of neuro-immune-metabolism and attempts to broaden the outlook when devising a scientific study or a treatment strategy.

Neuropeptide Y Is an Immunomodulatory Factor: Direct and Indirect

Neuropeptide Y (NPY), which is widely distributed in the nervous system, is involved in regulating a variety of biological processes, including food intake, energy metabolism, and emotional expression. However, emerging evidence points to NPY also as a critical transmitter between the nervous system and immune system, as well as a mediator produced and released by immune cells. In vivo and in vitro studies based on gene-editing techniques and specific NPY receptor agonists and antagonists have demonstrated that NPY is responsible for multifarious direct modulations on immune cells by acting on NPY receptors. Moreover, via the central or peripheral nervous system, NPY is closely connected to body temperature regulation, obesity development, glucose metabolism, and emotional expression, which are all immunomodulatory factors for the immune system. In this review, we focus on the direct role of NPY in immune cells and particularly discuss its indirect impact on the immune response.

Proliferating Infantile Hemangioma Tissues and Primary Cell Lines Express Markers Associated with Endothelial-to-Mesenchymal Transition

Supplemental Digital Content is available in the text.

Background:

We have previously shown that the endothelium of the microvessels of infantile hemangioma (IH) exhibits a hemogenic endothelium phenotype and proposed its potential to give rise to mesenchymal stem cells, similar to the development of hematopoietic cells. This endothelial-to-mesenchymal transition (Endo-MT) process involves the acquisition of a migratory phenotype by the endothelial cells, similar to epithelial-to-mesenchymal transition that occurs during neural crest development. We hypothesized that proliferating IH expresses Endo-MT–associated proteins and investigated their expression at the mRNA, protein, and functional levels.

Methods:

Immunohistochemical staining of paraffin-embedded sections of proliferating IH samples from 10 patients was undertaken to investigate the expression of the Endo-MT proteins Twist1, Twist2, Snail1, and Slug. Transcriptional analysis was performed for the same markers on proliferating IH tissues and CD34⁺ and CD34⁻ cells from proliferating IH-derived primary cell lines. Adipogenic and osteogenic differentiation plasticity was determined on the CD34-sorted fractions.

Results:

The endothelium of the microvessels and the cells within the interstitium of proliferating IH tissues expressed Twist1, Twist2, and Slug proteins. Twist1 was also expressed on the pericyte layer of the microvessels, whereas Snail1 was not expressed. Both CD34⁺ and CD34⁻ populations from the IH-derived primary cell lines underwent adipogenic and osteogenic differentiation.

Conclusions:

The expression of Endo-MT–associated proteins Twist1, Twist2, and Slug by both the endothelium of the microvessels and cells within the interstitium, and Twist1 on the pericyte layer of the microvessels of proliferating IH, suggest the presence of a process similar to Endo-MT. This may enable a tightly controlled primitive endothelium of proliferating IH to acquire a migratory mesenchymal phenotype with the ability to migrate away, providing a plausible explanation for the development of a fibrofatty residuum observed during involution of IH.

Infantile hemangiomas: what have we learned from propranolol?

PURPOSE OF REVIEW

Infantile hemangiomas are the most common vascular tumor of infancy. Treatment of infantile hemangiomas was revolutionized when propranolol, a nonselective β-blocker, was reported to be effective therapy. In this review, we highlight the lessons learned using propranolol to treat infantile hemangiomas. We also describe the ongoing effort to understand the mechanism of action of propranolol.

RECENT FINDINGS

Although the pathogenesis of infantile hemangiomas is not fully understood, maternal hypoxic stress and embolization of placental tissue are suggested to be critical components in their development. The mechanism of action of propranolol remains unclear, however various molecular mechanisms are detailed in this review. Propranolol treatment remains a well tolerated therapy, with low risk of adverse events or long-term neurocognitive effects. Dosing recommendations and optimal treatment duration vary among studies, and should be altered in patients with certain medical conditions such as Posterior fossa anomalies, Hemangioma, Arterial lesions, Cardiac abnormalities/coarctation of the aorta, Eye anomalies (PHACE) syndrome.

SUMMARY

Propranolol is a well tolerated and effective treatment for infantile hemangiomas. The efficacy of propranolol for infantile hemangiomas is clear, however questions pertaining to mechanism of action, pretreatment risk stratification, and optimal dosing remain unanswered. The guidelines for managing infantile hemangiomas with propranolol will continue to adapt as research catches up to clinical experience.

Phosphorylated Forms of STAT1, STAT3 and STAT5 Are Expressed in Proliferating but Not Involuted Infantile Hemangioma

We have recently demonstrated the expression of embryonic stem cell markers on the endothelium of infantile hemangioma, a functional hemogenic endothelium with the capacity for primitive erythropoiesis in vitro. Despite recent work characterizing stem cells within proliferating infantile hemangioma, the expression of STAT proteins, well documented for their roles in stem cell signaling, has not been investigated. 3,3-Diaminobenzidine and immunofluorescence immunohistochemical staining revealed expression of pSTAT1, pSTAT3 and pSTAT5 in proliferating infantile hemangioma samples with the strongest expression of pSTAT3. There was reduced expression of these pSTAT proteins in the involuted infantile hemangioma samples. Western blotting confirmed the identification of all these three proteins in proliferating infantile hemangioma. It is therefore not surprising that the phosphorylated/activated forms of these proteins are relatively abundantly expressed in proliferating, in comparison to involuted infantile hemangioma samples. We speculate that the reduced STAT activation, as infantile hemangioma involutes, is a reflection of the depletion of the abundant stem cells within proliferating infantile hemangioma, as the lesion involutes.

Do Neuroendocrine Peptides and Their Receptors Qualify as Novel Therapeutic Targets in Osteoarthritis?

Joint tissues like synovium, articular cartilage, meniscus and subchondral bone, are targets for neuropeptides. Resident cells of these tissues express receptors for various neuroendocrine-derived peptides including proopiomelanocortin (POMC)-derived peptides, i.e., α-melanocyte-stimulating hormone (α-MSH), adrenocorticotropin (ACTH) and β-endorphin (β-ED), and sympathetic neuropeptides like vasoactive intestinal peptide (VIP) and neuropeptide y (NPY). Melanocortins attained particular attention due to their immunomodulatory and anti-inflammatory effects in several tissues and organs. In particular, α-MSH, ACTH and specific melanocortin-receptor (MCR) agonists appear to have promising anti-inflammatory actions demonstrated in animal models of experimentally induced arthritis and osteoarthritis (OA). Sympathetic neuropeptides have obtained increasing attention as they have crucial trophic effects that are critical for joint tissue and bone homeostasis. VIP and NPY are implicated in direct and indirect activation of several anabolic signaling pathways in bone and synovial cells. Additionally, pituitary adenylate cyclase-activating polypeptide (PACAP) proved to be chondroprotective and, thus, might be a novel target in OA. Taken together, it appears more and more likely that the anabolic effects of these neuroendocrine peptides or their respective receptor agonists/antagonists may be exploited for the treatment of patients with inflammatory and degenerative joint diseases in the future.

Endogenous peptides profiles of human infantile hemangioma tissue and their clinical significance for treatment

Endogenous peptides play crucial roles in various biological processes. Their effects on the pathogenesis of human infantile hemangioma remains poorly understood. In this study, we construct a comparative peptidomic profiling between human infantile hemangioma tissue and matched normal skin using liquid chromatography-tandem mass spectrometry. A total of 192 peptides were significantly differentially expressed in human infantile hemangioma tissue, with 182 upregulated, and 10 downregulated peptides between infantile hemangioma tissue and matched normal skin. Performing bioinformatics analysis (Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis), we found that precursor proteins of these differentially expressed peptides correlate with metabolic process, biological regulation, binding, catalytic activity, and pathways in cancer occurring during pathological changes of infantile hemangioma. Furthermore, 89 differentially expressed peptides shared homology with antimicrobial peptides and 13 matched known immunomodulatory peptides based on prediction database. In conclusion, our results reveal significantly altered expression profiles of peptides in human infantile hemangioma tissue. These peptides may participate in the etiology of infantile hemangioma and provide beneficial scheme for clinical treatments.