Kinin B2 Receptor Mediates Cisplatin-Induced Painful Peripheral Neuropathy by Intracellular Kinase Pathways and TRPA1 Channel Sensitisation

An emerging aspect of cancer neuroscience: A literature review on chemotherapy-induced peripheral neuropathy

The nervous system governs both ontogeny and oncology. Foundational discoveries have clarified the direct communication of neurotransmitters with tumors and indirect interactions through neural effects on the immune system and the tumor microenvironment. Meantime, the nervous system is susceptible to cancer and its treatment. Chemotherapy-induced peripheral neuropathy (CIPN) is the most common side effects that significantly reduce the efficacy of anti-cancer treatment and patients' quality of life by leading to dose reduction or early cessation of chemotherapy. However, there are no effective strategies to reverse or treat CIPN. A better understanding of the mechanisms is expected to enable the development of the next generation of therapies. Here, we summarize the recent important studies on clinical manifestations, risk factors, prediction, pathogenesis, prevention, and treatment of CIPN. We also provide perspectives and insights regarding the rationales of bidirectional interactions between cancer and the nervous system.

Chemotherapy-Induced Peripheral Neuropathy: A Recent Update on Pathophysiology and Treatment

Chemotherapy-induced peripheral neuropathy (CIPN) is a major long-lasting side effect of some chemotherapy drugs, which threatens cancer survival rate. CIPN mostly affects sensory neurons and occasionally motor neurons, causing numbness, tingling, discomfort, and burning pain in the upper and lower extremities. The pathophysiology of CIPN is not completely understood; however, it is believed that chemotherapies induce peripheral neuropathy via directly damaging mitochondria, impairing the function of ion channels, triggering immunological mechanisms, and disrupting microtubules. The treatment of CIPN is a medical challenge, and there are no approved pharmacological options. Currently, duloxetine and other antidepressants, antioxidant, anti-inflammatory, and ion-channel targeted therapies are commonly used in clinics to relieve the symptoms of CIPN. Several other types of drugs, such as cannabinoids, sigma-1 receptor antagonists, and nicotinamides ribose, are being evaluated in preclinical and clinical studies. This paper summarizes the information related to the physiology of CIPN and medicines that could be used for treating this condition.

The analgesic effects of Yu-Xue-Bi tablet (YXB) on mice with inflammatory pain by regulating LXA4-FPR2-TRPA1 pathway

BACKGROUND

Oxylipins including lipoxin A4 (LXA4) facilitate the resolution of inflammation and possess analgesic properties by inhibiting macrophage infiltration and transient receptor potential (TRP) protein expression. Yu-Xue-Bi Tablet (YXB) is a traditional Chinese patent medicine used to relieve inflammatory pain. Our previous research has shown that the analgesic effect of YXB is related to inhibiting peripheral inflammation and regulating macrophage infiltration, but the mechanism is not yet clear. The purpose of this study is to explore the mechanisms of YXB on mice models with Complete Freund's Adjuvant (CFA)-induced inflammatory pain from the perspective at the resolution of inflammation.

METHODS

Mechanical allodynia thresholds and heat hypersensitivity were measured using the Von Frey test and the hot plate test respectively. The open field test and the tail suspension test were employed to measure anxiety and depressive behaviors respectively. The expression of CD68+ and the proportion of F4/80+CD11b+ cells were measured by immunofluorescence staining and flow cytometry. The expression of transient receptor potential ankyrin 1(TRPA1) was measured by immunofluorescence staining and western blotting. Oxylipins omics analysis provided quantitative data on oxylipins in the paws, and enzyme linked immunosorbent assay (ELISA) was used to measure the levels of LXA4 there. Immunofluorescence staining was used to perform the expression of Leukotriene A4 hydroxylase (LTA4H) in the paws of mice. The impact of injecting the formyl peptide receptor 2(FPR2) antagonist WRW4 and the TRPA1 agonist AITC into the left paws was observed, focusing on the expression of mechanical allodynia thresholds, the expression of CD68+, TRPA1 in the paws, and Calcitonin gene-related peptide (CGRP) in the L5 spinal dorsal horn.

RESULTS

YXB elevated mechanical allodynia thresholds, alleviated heat hypersensitivity and anxiety and depressive behaviors in CFA mice. It significantly reduced the number of CD68+ and proportion of F4/80+CD11b+ within the paws, thereby decreasing macrophage infiltration. Additionally, it diminished the expression of TRPA1 in the paws and TRPV1 in the DRG, leading to an inhibition of peripheral sensitization. Through quantitative analysis, it was found that YXB could modulate DHA-derived oxylipins and LXA4. ELISA results indicated that YXB elevated the levels of LXA4 and inhibited the expression of LAT4H in the paws. Furthermore, the pro-resolution and analgesic effects of YXB were hindered after administration of the FPR2 antagonist. Compared with the AITC group, YXB showed no significant improvement in anti-inflammatory and analgesic effects.

CONCLUSIONS

YXB can regulate the oxylipins of paws in CFA mice to promote the resolution of inflammation. The LXA4-FPR2-TRPA1 pathway is a key mechanism for the resolution of inflammation and analgesic effects.

G Protein-Coupled Receptors and Ion Channels Involvement in Cisplatin-Induced Peripheral Neuropathy: A Review of Preclinical Studies

Cisplatin is a platinum-based chemotherapy drug widely used to treat various solid tumours. Although it is effective in anti-cancer therapy, many patients develop peripheral neuropathy during and after cisplatin treatment. Peripheral neuropathy results from lesions or diseases in the peripheral somatosensory nervous system and is a significant cause of debilitation and suffering in patients. In recent years, preclinical studies have been conducted to elucidate the mechanisms involved in chemotherapy-induced peripheral neuropathic pain, as well as to promote new therapeutic targets since current treatments are ineffective and are associated with adverse effects. G-protein coupled receptors and ion channels play a significant role in pain processing and may represent promising targets for improving the management of cisplatin-induced neuropathic pain. This review describes the role of G protein-coupled receptors and ion channels in cisplatin-induced pain, analysing preclinical experimental studies that investigated the role of each receptor subtype in the modulation of cisplatin-induced pain.