NADPH oxidase 4 regulate the glycolytic metabolic reprogramming of microglial cells to promote M1 polarization

The Role of PKM2 in Multiple Signaling Pathways Related to Neurological Diseases

Pyruvate kinase M2 (PKM2) is a key rate-limiting enzyme in glycolysis. It is well known that PKM2 plays a vital role in the proliferation of tumor cells. However, PKM2 can also exert its biological functions by mediating multiple signaling pathways in neurological diseases, such as Alzheimer's disease (AD), cognitive dysfunction, ischemic stroke, post-stroke depression, cerebral small-vessel disease, hypoxic-ischemic encephalopathy, traumatic brain injury, spinal cord injury, Parkinson's disease (PD), epilepsy, neuropathic pain, and autoimmune diseases. In these diseases, PKM2 can exert various biological functions, including regulation of glycolysis, inflammatory responses, apoptosis, proliferation of cells, oxidative stress, mitochondrial dysfunction, or pathological autoimmune responses. Moreover, the complexity of PKM2's biological characteristics determines the diversity of its biological functions. However, the role of PKM2 is not entirely the same in different diseases or cells, which is related to its oligomerization, subcellular localization, and post-translational modifications. This article will focus on the biological characteristics of PKM2, the regulation of PKM2 expression, and the biological role of PKM2 in neurological diseases. With this review, we hope to have a better understanding of the molecular mechanisms of PKM2, which may help researchers develop therapeutic strategies in clinic.

Metabolic Reprogramming in Gliocyte Post-cerebral Ischemia/ Reperfusion: From Pathophysiology to Therapeutic Potential

Ischemic stroke is a leading cause of disability and death worldwide. However, the clinical efficacy of recanalization therapy as a preferred option is significantly hindered by reperfusion injury. The transformation between different phenotypes of gliocytes is closely associated with cerebral ischemia/ reperfusion injury (CI/RI). Moreover, gliocyte polarization induces metabolic reprogramming, which refers to the shift in gliocyte phenotype and the overall transformation of the metabolic network to compensate for energy demand and building block requirements during CI/RI caused by hypoxia, energy deficiency, and oxidative stress. Within microglia, the pro-inflammatory phenotype exhibits upregulated glycolysis, pentose phosphate pathway, fatty acid synthesis, and glutamine synthesis, whereas the anti-inflammatory phenotype demonstrates enhanced mitochondrial oxidative phosphorylation and fatty acid oxidation. Reactive astrocytes display increased glycolysis but impaired glycogenolysis and reduced glutamate uptake after CI/RI. There is mounting evidence suggesting that manipulation of energy metabolism homeostasis can induce microglial cells and astrocytes to switch from neurotoxic to neuroprotective phenotypes. A comprehensive understanding of underlying mechanisms and manipulation strategies targeting metabolic pathways could potentially enable gliocytes to be reprogrammed toward beneficial functions while opening new therapeutic avenues for CI/RI treatment. This review provides an overview of current insights into metabolic reprogramming mechanisms in microglia and astrocytes within the pathophysiological context of CI/RI, along with potential pharmacological targets. Herein, we emphasize the potential of metabolic reprogramming of gliocytes as a therapeutic target for CI/RI and aim to offer a novel perspective in the treatment of CI/RI.

Role and anti-inflammatory mechanisms of acupuncture and moxibustion therapy on pain relief through NOX-ROS-NLRP3 pathway in CCI rats models

OBJECTIVE

To observe the effects of acupuncture and moxibustion therapy on pain relief in sciatica rats and to explore the mechanism of its anti-inflammatory effect.

METHODS

SPF grade 4-6-week-old Kunming rats were randomly divided into 5 groups including a blank group, sham-operated group, model group, acupuncture, and moxibustion (AnM) group, and positive group. A total of 10 rats were included in each group. The model group, the AnM group, and the positive group were prepared by ligating the left sciatic nerve. AnM group was used for acupuncture and moxibustion therapy intervention, and the positive group was rendered to quick-acting sciatica pills once a day for 7 days (3 courses of treatment). The blank group, sham-operated group, and model group were not treated. The changes in thermal and mechanical pain thresholds were observed before and after the operation, and the morphological changes of the dorsal horn of the spinal cord in the lumbosacral region of the rats in each group were observed by HE staining after the courses of treatment finished. The contents of IL-1β, IL-6, IL-18, and TNF-α were measured by ELISA and the expressions of NOX1, NOX2, NOX4, and NLRP3 genes were detected by RT-qPCR while the protein expressions of NOX1, NOX2, NOX4 and NLRP3 were analyzed by Western blotting.

RESULTS

The AnM and positive group showed a significant increase in thermal and mechanical pain thresholds after treatment, while there was no significant change in the model group. As compared to the control group, the contents of IL- 1β, IL-6, IL-18, and TNF-α, as well as the relative expressions of NOX1, NOX2, NOX4, and NLRP3 genes were significantly increased in the model group (P < 0.05 or P < 0.01). As compared to the model group, the contents of IL-1β, IL-6, IL-18, and TNF-α, as well as the relative expressions of NOX1, NOX2, NOX4, and NLRP3 genes significantly decreased in the AnM and positive groups (P < 0.05 or P < 0.01). The pathological changes of inflammatory infiltration of tissue cells in the dorsal horn of the lumbosacral spinal cord were slowed in the AnM group.

CONCLUSION

Acupuncture and moxibustion therapy have a positive effect on pain relief and anti-inflammatory effects in CCI sciatica rats, which may point to the regulation of NOX1, NOX2, NOX4, and NLRP3 expressions, and inhibition of ROS.