Production, characterization, and application of a monoclonal antibody specific for the extracellular domain of human P2X7R

Animal Models for the Investigation of P2X7 Receptors

The P2X7 receptor is a trimeric ligand-gated cation channel activated by extracellular adenosine 5'-triphosphate. The study of animals has greatly advanced the investigation of P2X7 and helped to establish the numerous physiological and pathophysiological roles of this receptor in human health and disease. Following a short overview of the P2X7 distribution, roles and functional properties, this article discusses how animal models have contributed to the generation of P2X7-specific antibodies and nanobodies (including biologics), recombinant receptors and radioligands to study P2X7 as well as to the pharmacokinetic testing of P2X7 antagonists. This article then outlines how mouse and rat models have been used to study P2X7. These sections include discussions on preclinical disease models, polymorphic P2X7 variants, P2X7 knockout mice (including bone marrow chimeras and conditional knockouts), P2X7 reporter mice, humanized P2X7 mice and P2X7 knockout rats. Finally, this article reviews the limited number of studies involving guinea pigs, rabbits, monkeys (rhesus macaques), dogs, cats, zebrafish, and other fish species (seabream, ayu sweetfish, rainbow trout and Japanese flounder) to study P2X7.

Research Progress in the Relationship Between P2X7R and Cervical Cancer

Cervical cancer is one of the most common and serious tumors in women. Finding new biomarkers and therapeutic targets plays an important role in the diagnosis, prognosis, and treatment of cervical cancer. Purinergic ligand-gated ion channel 7 receptor (P2X7R) is a purine ligand cation channel, activated by adenosine triphosphate (ATP). Studies have shown that P2X7R plays an important role in a variety of diseases and cancers. More and more studies have shown that P2X7R is also closely related to cervical cancer; therefore, the role of P2X7R in the development of cervical cancer deserves further discussion. The expression level of P2X7R in uterine epithelial cancer tissues was lower than that of the corresponding normal tissues. P2X7R plays an important role in the apoptotic process of cervical cancer through various mechanisms of action, and both antagonists and agonists of P2X7R can inhibit the proliferation of cervical cancer cells, while P2X7R is involved in the antitumor effect of Atr-I on cervical cancer cells. This review evaluates the current role of P2X7R in cervical cancer in order to develop more specific therapies for cervical cancer. In conclusion, P2X7R may become a biomarker for cervical cancer screening, and even a new target for clinical treatment of cervical cancer.

The Role of Purinergic P2X7 Receptor in Inflammation and Cancer: Novel Molecular Insights and Clinical Applications

The purinergic P2X7 receptor (P2X7R) is a transmembrane protein whose expression has been related to a variety of cellular processes, while its dysregulation has been linked to inflammation and cancer. P2X7R is expressed in cancer and immune system cell surfaces. ATP plays a key role in numerous metabolic processes due to its abundance in the tumour microenvironment. P2X7R plays an important role in cancer by interacting with ATP. The unusual property of P2X7R is that stimulation with low doses of ATP causes the opening of a permeable channel for sodium, potassium, and calcium ions, whereas sustained stimulation with high doses of ATP favours the formation of a non-selective pore. The latter effect induces a change in intracellular homeostasis that leads to cell death. This evidence suggests that P2X7R has both pro- and anti-tumour proprieties. P2X7R is increasingly recognised as a regulator of inflammation. In this review, we aimed to describe the most relevant characteristics of P2X7R function, activation, and its ligands, while also summarising the role of P2X7R activation in the context of inflammation and cancer. The currently used therapeutic approaches and clinical trials of P2X7R modulators are also described.

Cancer Metabostemness and Metabolic Reprogramming via P2X7 Receptor

The heterogeneity of tumor cell mass and the plasticity of cancer cell phenotypes in solid tumors allow for the insurgence of resistant and metastatic cells, responsible for cancer patients' clinical management's main challenges. Among several factors that are responsible for increased cancer aggression, metabolic reprogramming is recently emerging as an ultimate cancer hallmark, as it is central for cancer cell survival and self-renewal, metastasis and chemoresistance. The P2X7 receptor, whose expression is upregulated in many solid and hematological malignancies, is also emerging as a good candidate in cancer metabolic reprogramming and the regulation of stem cell proliferation and differentiation. Metabostemness refers to the metabolic reprogramming of cancer cells toward less differentiated (CSCs) cellular states, and we believe that there is a strong correlation between metabostemness and P2X7 receptor functions in oncogenic processes. Here, we summarize important aspects of P2X7 receptor functions in normal and tumor tissues as well as essential aspects of its structure, regulation, pharmacology and its clinical use. Finally, we review current knowledge implicating P2X7 receptor functions in cancer-related molecular pathways, in metabolic reprogramming and in metabostemness.

The Expression of P2X7 Receptor on Th1, Th17, and Regulatory T Cells in Patients with Systemic Lupus Erythematosus or Rheumatoid Arthritis and Its Correlations with Active Disease

P2X7 receptor (P2X7R) is highly expressed on immune cells, triggering the release of cytokines and regulating autoimmune responses. To investigate P2X7R surface expression on T helper (Th) 1, Th17, and regulatory T (Treg) cells in patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) and correlations with disease activity, 29 SLE and 29 RA patients and 18 healthy controls (HCs) were enrolled. We showed that SLE and RA patients had significantly higher levels of plasma cytokines (IFN-γ, IL-1β, IL-6, IL-17A, and IL-23), frequencies of Th1 and Th17 cells, and expression of P2X7R on Th1 and Th17 than HCs, and the Th17/Treg ratio was significantly increased, whereas Treg cell levels were significantly decreased. The Ca²⁺ influx increase following BzATP stimulation was significantly higher in CD4⁺PBMCs from SLE and RA patients than in HCs. Blood levels of shed P2X7R were increased in SLE and RA patients. Furthermore, 28-joint Disease Activity Score and SLE Disease Activity Index score showed negative correlations with Treg cell levels and positive correlations with Th17/Treg ratio and Th17 cell P2X7R expression. Interestingly, Th17 cell P2X7R expression was closely correlated with IL-1β, C-reactive protein, the erythrocyte sedimentation rate, anticyclic citrullinated peptide Abs, albumin, and C4. These data indicate that increased Th17 cell P2X7R expression is functionally and positively related to disease activity and some inflammatory mediators in SLE and RA patients, and P2X7R could be critical in promoting the Th17 immune response and contributing to the complex pathogenesis of SLE and RA.

The P2X7 Receptor: Central Hub of Brain Diseases

The P2X7 receptor is a cation channel activated by high concentrations of adenosine triphosphate (ATP). Upon long-term activation, it complexes with membrane proteins forming a wide pore that leads to cell death and increased release of ATP into the extracellular milieu. The P2X7 receptor is widely expressed in the CNS, such as frontal cortex, hippocampus, amygdala and striatum, regions involved in neurodegenerative diseases and psychiatric disorders. Despite P2X7 receptor functions in glial cells have been extensively studied, the existence and roles of this receptor in neurons are still controversially discussed. Regardless, P2X7 receptors mediate several processes observed in neuropsychiatric disorders and brain tumors, such as activation of neuroinflammatory response, stimulation of glutamate release and neuroplasticity impairment. Moreover, P2X7 receptor gene polymorphisms have been associated to depression, and isoforms of P2X7 receptors are implicated in neuropsychiatric diseases. In view of that, the P2X7 receptor has been proposed to be a potential target for therapeutic intervention in brain diseases. This review discusses the molecular mechanisms underlying P2X7 receptor-mediated signaling in neurodegenerative diseases, psychiatric disorders, and brain tumors. In addition, it highlights the recent advances in the development of P2X7 receptor antagonists that are able of penetrating the central nervous system.