Targeting tumor suppressor p53 for organ fibrosis therapy.

Fibrosis is a reparative and progressive process characterized by abnormal extracellular matrix deposition, contributing to organ dysfunction in chronic diseases. The tumor suppressor p53 (p53), known for its regulatory roles in cell proliferation, apoptosis, aging, and metabolism across diverse tissues, appears to play a pivotal role in aggravating biological processes such as epithelial-mesenchymal transition (EMT), cell apoptosis, and cell senescence. These processes are closely intertwined with the pathogenesis of fibrotic disease. In this review, we briefly introduce the background and specific mechanism of p53, investigate the pathogenesis of fibrosis, and further discuss p53's relationship and role in fibrosis affecting the kidney, liver, lung, and heart. In summary, targeting p53 represents a promising and innovative therapeutic approach for the prevention and treatment of organ fibrosis.

Blockade of spinal dopamine D1/D2 receptor suppresses activation of NMDA receptor through Gαq and Src kinase to attenuate chronic bone cancer pain.

INTRODUCTION: Spinal N-methyl-D-aspartate receptor (NMDAR) is vital in chronic pain, while NMDAR antagonists have severe side effects. NMDAR has been reported to be controlled by G protein coupled receptors (GPCRs), which might present new therapeutic targets to attenuate chronic pain. Dopamine receptors which belong to GPCRs have been reported could modulate the NMDA-mediated currents, while their exact effects on NMDAR in chronic bone cancer pain have not been elucidated. OBJECTIVES: This study was aim to explore the effects and mechanisms of dopamine D1 receptor (D1DR) and D2 receptor (D2DR) on NMDAR in chronic bone cancer pain. METHODS: A model for bone cancer pain was established using intra-tibia bone cavity tumor cell implantation (TCI) of Walker 256 in rats. The nociception was assessed by Von Frey assay. A range of techniques including the fluorescent imaging plate reader, western blotting, and immunofluorescence were used to detect cell signaling pathways. Primary cultures of spinal neurons were used for in vitro evaluation. RESULTS: Both D1DR and D2DR antagonists decreased NMDA-induced upregulation of Ca2+ oscillations in primary culture spinal neurons. Additionally, D1DR/D2DR antagonists inhibited spinal Calcitonin Gene-Related Peptide (CGRP) and c-Fos expression and alleviated bone cancer pain induced by TCI which could both be reversed by NMDA. And D1DR/D2DR antagonists decreased p-NR1, p-NR2B, and Gαq protein, p-Src expression. Both Gαq protein and Src inhibitors attenuated TCI-induced bone cancer pain, which also be reversed by NMDA. The Gαq protein inhibitor decreased p-Src expression. In addition, D1DR/D2DR antagonists, Src, and Gαq inhibitors inhibited spinal mitogen-activated protein kinase (MAPK) expression in TCI rats, which could be reversed by NMDA. CONCLUSIONS: Spinal D1DR/D2DR inhibition eliminated NMDAR-mediated spinal neuron activation through Src kinase in a Gαq-protein-dependent manner to attenuate TCI-induced bone cancer pain, which might present a new therapeutic strategy for bone cancer pain.

Levo-corydalmine attenuates microglia activation and neuropathic pain by suppressing ASK1-p38 MAPK/NF-κB signaling pathways in rat spinal cord.

BACKGROUND AND OBJECTIVES: Neuropathic pain is partially refractory to currently available treatments. Although some studies have reported that apoptosis signal-regulating kinase 1 (ASK1) may inhibit chronic pain, the mechanisms underlying this process have not been fully elucidated. METHODS: Chronic constriction injury (CCI) of the rat sciatic nerve was used to establish a neuropathic pain model. Nociception was assessed using von Frey hair and Hargreaves' methods. Western blot and immunofluorescence were used to detect the cell signaling pathway. BV2 cell line was cultured for in vitro evaluation. RESULTS: Our results indicated that spinal ASK1 was co-expressed with the microglia marker ionized calcium binding adaptor 1. Additionally, intrathecal administration of ASK1 inhibitor suppressed the activation of spinal microglia and attenuated CCI-induced neuropathic pain. The ASK1 inhibitor also decreased the levels of phosphorylated ASK1 (p-ASK1), p65, p38 mitogen-activated protein kinase (MAPK) and tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) messenger RNA in lipopolysaccharide-stimulated BV2 microglia cells. Intragastric administration of levo-corydalmine (l-CDL) significantly attenuated CCI-induced neuropathic pain and inhibited the expression of p-ASK1 in the spinal cord. l-CDL conspicuously suppressed the activation of spinal microglia in vitro and in vivo. Translocation of nuclearfactor-kappa B (NF-κB) and upregulation of p-p65, TNF-α, IL-1ß were inhibited by l-CDL. Further, the analgesic effects of l-CDL were associated with reduced levels of phosphorylated protein kinase C (PKC γ), c-JunNH2-terminal kinase, and extracellular signal-regulated kinase. CONCLUSIONS: This study showed that the expression of ASK1 in spinal microglia and ASK1 inhibitor suppressed microglia activation via suppression of p38 MAPK/NF-κB, which ultimately attenuated CCI-induced neuropathic pain. l-CDL also inhibited the ASK1-P38 MAPK/NF-κB axis to attenuate CCI-induced neuropathic pain.

Selective blockade of spinal D2DR by levo-corydalmine attenuates morphine tolerance via suppressing PI3K/Akt-MAPK signaling in a MOR-dependent manner.

Morphine tolerance remains a challenge in the management of chronic pain in the clinic. As shown in our previous study, the dopamine D2 receptor (D2DR) expressed in spinal cord neurons might be involved in morphine tolerance, but the underlying mechanisms remain to be elucidated. In the present study, selective spinal D2DR blockade attenuated morphine tolerance in mice by inhibiting phosphatidylinositol 3 kinase (PI3K)/serine-threonine kinase (Akt)-mitogen activated protein kinase (MAPK) signaling in a µ opioid receptor (MOR)-dependent manner. Levo-corydalmine (l-CDL), which exhibited micromolar affinity for D2DR in D2/CHO-K1 cell lines in this report and effectively alleviated bone cancer pain in our previous study, attenuated morphine tolerance in rats with chronic bone cancer pain at nonanalgesic doses. Furthermore, the intrathecal administration of l-CDL obviously attenuated morphine tolerance, and the effect was reversed by a D2DR agonist in mice. Spinal D2DR inhibition and l-CDL also inhibited tolerance induced by the MOR agonist DAMGO. l-CDL and a D2DR small interfering RNA (siRNA) decreased the increase in levels of phosphorylated Akt and MAPK in the spinal cord; these changes were abolished by a PI3K inhibitor. In addition, the activated Akt and MAPK proteins in mice exhibiting morphine tolerance were inhibited by a MOR antagonist. Intrathecal administration of a PI3K inhibitor also attenuated DAMGO-induced tolerance. Based on these results, l-CDL antagonized spinal D2DR to attenuate morphine tolerance by inhibiting PI3K/Akt-dependent MAPK phosphorylation through MOR. These findings provide insights into a more versatile treatment for morphine tolerance.