Purinergic Signalling最新文献

Parkinson's disease (PD) is marked by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Adenosine receptors (A_2ARs) modulate the striatopallidal non-dopaminergic pathway to alleviate PD symptoms. In the present study, the neuroprotective mechanism of the selective A_2AR antagonist exhibiting a non-purine scaffold, IDPU (K_i = 0.0038 nM), was explored using the primary mid-brain neuronal (PMDN) cells isolated from P₀/P₁ rat pups that differentiated to form dopaminergic neurons, as validated using tyrosine hydroxylase. PMDN cells, when treated with IDPU (0-10 μM) alone, showed insignificant toxicity. However, they exhibited < 60% cell viability when treated with 6-OHDA (150 μM) after 24h. Cell viability improved to > 80%, and dopamine levels were restored in 6-OHDA- (150 μM) induced PMDN cells when 3h post-treated with IDPU (0.7 μM, 1 μM), including the depletion in ROS generation and [Ca²⁺]_i levels observed after 24h. IDPU treatment further impacts the mitochondrial control by attenuating both mitochondrial SOD production and its membrane potential loss in PD-like conditions. To investigate the mechanism of A_2AR intervention on governing the mitochondrial-associated signalling cascades, the proteins were isolated from 6-OHDA (150 μM) induced PMDN cells 3h post-treated with IDPU (0.7 μM, 1 μM) and ZM241385 (1 μM) for western blot analysis. Our results exhibited that the phosphorylation of both DRP1 (Ser616) (78 kDa) and p38MAPK (Tyr182) (41 kDa) proteins was enhanced when exposed to 6-OHDA; however, the protein levels reduced post-treatment with both A_2AR antagonists. In contrast, 6-OHDA toxicity alleviated the levels of both Parkin (58 kDa) and DJ-1(23 kDa), while exposure to A_2AR antagonists (IDPU and ZM241385) improved their protein levels. This suggests the possible involvement of A_2AR blockade in regulating mitochondrial dynamics, thus promoting survival. These findings present the first evidence that IDPU demonstrates neuroprotection in PDlike conditions via the p38MAPK/DRP1/Parkin signalling, offering a potential therapeutic mechanism for targeting mitochondrial dynamics through A_2AR antagonism.

Trauma and hemorrhagic shock (T/HS) trigger systemic inflammation and multiorgan injury, yet the molecular mediators of this response remain incompletely defined. Purinergic receptors, including P2X4 and P2X7, are key regulators of innate immune signaling and may contribute to post-trauma organ dysfunction. Here, we assessed the roles of P2X4 and P2X7 in T/HS-induced injury across multiple organs using genetic and pharmacologic approaches in murine models. Global P2X4 knockout (KO) mice exhibited significantly reduced injury in the lung as reflected by improved histopathology, decreased myeloperoxidase activity, and preserved tissue architecture. Additionally, P2X4 KO reduced liver and kidney injury, as indicated by plasma liver enzymes and blood urea nitrogen levels. Myeloid-specific P2X4 deficiency recapitulated these protective effects, suggesting a central role for myeloid cell-mediated P2X4 signaling in multiorgan injury. Bulk RNA sequencing of lung tissue from P2X4 KO mice revealed altered expression of immune response genes, including downregulation of P2X7. Pharmacological inhibition of P2X7 reduced injury in the lung, liver, and kidney. Both P2X4 and P2X7 expressions were downregulated in affected organs following T/HS. These findings identify P2X4, particularly in myeloid cells, as a key driver of multiorgan injury following T/HS, and support further investigation of P2 receptor modulation as a therapeutic strategy in trauma-induced organ injury.

Myocardial infarction (MI) is a leading cause of heart failure and ventricular arrhythmias, driven by excessive inflammation and adverse cardiac remodeling. The purinergic P2X7 receptor (P2X7R) plays a critical role in acute MI, however, the long-term effect of P2X7R on chronic MI and arrhythmia remains unknown. This study investigated the effects of long-term modulation of P2X7R on inflammation, fibrosis, and arrhythmias in a rat model of MI. Male Sprague-Dawley rats underwent left anterior descending coronary artery ligation and were assigned to sham, MI, MI + Brilliant Blue G (BBG, P2X7R antagonist), or MI + BzATP (P2X7R agonist) groups for 28 days. BBG treatment significantly reduced ventricular tachycardia induction rates, shortened QT, QTc, and Tpeak-Tend intervals, and improved cardiac function, as evidenced by increased ejection fraction, fractional shortening, and cardiac output. Histological analyses revealed reduced inflammatory cell infiltration, necrosis, and collagen deposition in the MI + BBG group compared to MI groups. ELISA confirmed that BBG lowered pro-inflammatory cytokines TNF-α, IL-1β and TGF-β1 levels. P2X7 mRNA expression was attenuated by BBG, but not significantly altered. These findings demonstrate that BBG mitigates post-MI inflammation, fibrosis, and arrhythmias while enhancing cardiac function.

Our sense of hearing commences in the cochlea, the peripheral sensory organ for hearing. Spiral ganglion neurons (SGN) in the cochlea are primary auditory neurons responsible for auditory neurotransmission. There are two classes of SGNs: type I SGNs, which make up 90-95% of the SGN population, and type II SGNs, which make up the remainder. Previous studies have shown that SGNs express a combination of purinergic (P2X, P2Y and adenosine) receptors at the mRNA and protein levels. In this study, we have focused on the P2X1 receptor to characterise its expression pattern in the Wistar rat cochlea at postnatal day 8 and in adult (6-8-week-old) rats of both genders using immunohistochemistry. Our results show differential expression of P2X1 receptors in 9.4-14.2% of SGNs in the adult cochlea, and 14.2-23.3% in the cochlea of P8 pups. In most of these neurons, P2X1 receptors were co-expressed with peripherin-1, an established type II SGN marker. These results suggest a potential role for the P2X1 receptor as a modulator of auditory neurotransmission in type II spiral ganglion neurons.

Cancer is a group of diseases characterized by disordered cell proliferation and loss of tissue architecture. Breast cancer (BC) is the most common and lethal cancer among women, standing out for its molecular, histological and pathological heterogeneity. The BC tumor microenvironment (TME) is a complex ecosystem comprising transformed cells and a multitude of non-tumor cells, embedded in an altered extracellular matrix. Endothelial cells are present, driving angiogenesis, a relevant hallmark that ensures nutrition and oxygenation through the formation of new blood vessels. During this process, a complex network of molecules is released by tumor and endothelial cells, such as Vascular Endothelial Growth Factor (VEGF), that, in turn, induce cancer progression, diffusion, and metastasis. Purinergic signaling also regulates the functioning of endothelial cells involving the action of purines (ATP, ADP, UTP, UDP and adenosine) as signaling in purinergic receptors, with their concentration modulated by enzymes known as ectonucleotidases. This review aims to explore the contribution of purinergic signaling to BC angiogenesis, highlighting potential therapeutic targets currently under scientific focus. In general, the TME presents overexpression of ATP and adenosine, which stimulate endothelial cells through purinergic receptors. This stimulus promotes the formation of new vessels, mainly via the release of VEGF. Thus, purinergic signaling emerges as a central mechanism in BC angiogenesis, with potential to be explored in the development of antitumor therapies.

Chronic kidney disease (CKD) affects approximately 13.4% of the global population and significantly impacts patients' quality of life. This study aimed to investigate the effects of resistance exercise on blood pressure and purinergic signaling in patients with CKD. Here, 28 patients with CKD performed a 12-week resistance exercise protocol during hemodialysis. Blood samples were collected before and after the intervention. Biochemical analyses, for example, NTPDases, ecto-5'-nucleotidase, and adenosine deaminase, were measured in platelets. Flow cytometry was performed to investigate CD39 and CD73 expression on lymphocytes. In addition, extracellular ATP and blood pressure were analyzed. Our findings revealed that patients with CKD present high systolic blood pressure (p = 0.0002) compared to control, and resistance exercise reduces blood pressure in these patients (p = 0.007). Regarding purinergic signaling, an increase in NTPDases, ecto-5'-nucleotidase, and adenosine deaminase was observed in patients with CKD (p = 0.0001; p = 0.0001; p = 0.0001; p = 0.0007, respectively). Surprisingly, after resistance exercise, NTPDase/ATP and ecto-5'-nucleotidase decreased (p = 0.0006; p = 0.02). CD39 and CD73 expression significantly increased on lymphocytes of CKD patients compared to control (p = 0.004; p = 0.0002, respectively). After resistance exercise, CD39 and CD73 expression was downregulated. Extracellular ATP levels were decreased in CKD (p = 0.0001), and resistance exercise restored these levels. In conclusion, CKD patients present high activity and expression of CD39 and CD73 enzymes, and resistance exercise mitigated purinergic exacerbation and presents anti-hypertensive effects in patients with CKD.

Allodynia to mechanical stimuli is one of the most prevalent symptoms in paclitaxel-treated cancer patients. Paclitaxel induces ATP release from nerve terminals; thus, peripheral primary sensory neurons can be sensitized by ATP, as a large subgroup expresses purinergic P2X_2/3 and P2X₃ receptors. In this study, we examined the role of P2X_2/3 and P2X₃ receptors in paclitaxel-treated rats with allodynia. We assessed the paw withdrawal threshold as an allodynia test on paclitaxel-treated rats and evaluated the intrathecal and systemic effects of purinergic receptor antagonists and the transient knockdown of P2X₃ receptor expression in male and female allodynic rats. A single dose of paclitaxel decreased the paw withdrawal threshold to mechanical stimulation in both sexes. Pharmacological blockade of spinal P2X₃ and P2X_2/3 receptors with Ro-51, TNP-ATP, and systemic suramin reversed allodynia in paclitaxel-treated rats. In addition, the transient knockdown of P2X₃ receptors with intrathecal siRNA administration had an antiallodynic effect that lasted until 72 h post-transfection. Paclitaxel produced an increase in the P2X₃ receptor expression in dorsal root ganglia but not in dorsal horn spinal cord. In conclusion, spinal P2X_2/3 and P2X₃ receptors have a significant role in allodynia to mechanical stimulation in paclitaxel-treated rats, regardless of sex. Therefore, the blockade of these receptors could be an alternative pharmacological target for alleviating sensory symptoms of paclitaxel-induced peripheral neuropathy in patients with cancer.