DNMT1 Mediates Chronic Pain-Related Depression by Inhibiting GABAergic Neuronal Activation in the Central Amygdala

Neurotransmitter imbalance and amygdala synaptic plasticity in lumbar disc herniation-induced chronic pain and related emotional Disturbances:A multi-omics analysis

Chronic pain due to lumbar disc herniation (LDH) significantly impairs quality of life and is often accompanied by emotional disturbances, such as anxiety and depression. Despite the recognition of these comorbidities, the underlying neural mechanisms remain unclear. This study investigates the role of neurotransmitter imbalances and key regulatory molecules in LDH-induced chronic pain and related emotional disturbances, with a focus on synaptic plasticity in the amygdala. A rat model of LDH was developed using male Sprague-Dawley rats. Behavioral assessments were conducted to evaluate pain hypersensitivity, anxiety, and depression-like behaviors. Cerebrospinal fluid (CSF) metabolomics and amygdala transcriptomics were employed to analyze neurotransmitter profiles and gene expression. In vitro experiments were conducted to explore the role of PRKCG in synaptic plasticity. Behavioral tests showed significant pain hypersensitivity and anxiety- and depression-like behavior in LDH rats. Metabolomic analysis revealed altered levels of glutamate and γ-aminobutyric acid (GABA) in the CSF, indicating neurotransmitter imbalances. Transcriptomic profiling identified changes in genes related to synaptic plasticity, including PRKCG. PRKCG knockdown led to reduced CAMKII phosphorylation and GRIA1 expression, supporting its role in modulating synaptic plasticity. This study provides evidence that neurotransmitter imbalances and alterations in synaptic plasticity within the amygdala may contribute to the persistence of chronic pain and associated emotional disturbances in LDH. PRKCG may represent a novel therapeutic target for treating both chronic pain and related emotional disturbances.

The persistent pain enigma: Molecular drivers behind acute-to-chronic transition

The transition from acute to chronic pain is a complex and multifactorial process that presents significant challenges in both diagnosis and treatment. Key mechanisms of peripheral and central sensitization, neuroinflammation, and altered synaptic plasticity contribute to the amplification of pain signals and the persistence of pain. Glial cell activation, particularly microglia and astrocytes, is pivotal in developing chronic pain by releasing pro-inflammatory cytokines that enhance pain sensitivity. This review explores the molecular, cellular, and systemic mechanisms underlying the transition from acute to chronic pain, offering new insights into the molecular and neurobiological mechanisms involved, which are often underexplored in existing literature. It also addresses emerging therapeutic strategies beyond traditional pain management, offering valuable perspectives for future research and clinical applications.

Air pollution and prostate cancer: Unraveling the connection through network toxicology and machine learning

BACKGROUND

In recent years, air pollution has been demonstrated to be associated with the occurrence of various diseases. This study aims to explore the potential association between air pollutants and prostate cancer (PCa) and to identify key genes that may play a critical bridging role in this process.

METHODS

This study utilized multiple online databases to obtain relevant target genes associated with air pollutants and PCa. Protein-protein interaction (PPI) analysis and visualization were conducted for the intersecting genes, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses to explore potential mechanisms. Subsequently, the best predictive model was selected through a combination of 108 machine learning algorithms. A prognostic model was constructed using the Random Survival Forest (RSF) model in conjunction with Lasso regression model, and its performance was validated in four external datasets. Finally, molecular docking analysis was conducted to investigate the interaction between key genes and air pollutants.

RESULTS

Seven common air pollutants (benzene, SO₂, NO, CO, NO₂, toluene, and O₃) were selected for analysis, and 48 intersecting targets related to PCa were identified. GO and KEGG functional enrichment analyses revealed that these targets are primarily involved in regulating biological processes such as apoptosis, carcinogenesis, and cell proliferation. Based on machine learning algorithm selection, the combination of RSF and Lasso regression was identified as the optimal predictive model, which highlighted five key genes associated with air pollutants and PCa. The model exhibited strong predictive performance across all four independent external datasets. Additionally, molecular docking analysis further confirmed the potential interactions between air pollutants and these core targets.

CONCLUSION

The findings suggest that HDAC6, CDK1, DNMT1, NOS3, and DPP4 play crucial roles in the process by which air pollutants influence PCa. The results offer new insights into the molecular mechanisms linking air pollutants and PCa, highlighting the need for greater public awareness of air pollution issues.

Exploring the impact of environmental factors on male reproductive health through epigenetics

Male infertility has become an increasingly severe global health issue, with its incidence significantly rising over the past few decades. This paper delves into the crucial role of epigenetics in male reproductive health, focusing particularly on the effects of DNA methylation, histone modifications, chromatin remodeling and non-coding RNAs regulation on spermatogenesis. Exposure to various environmental factors can cause sperm DNA damage, leading to epigenetic abnormalities. Among these factors, we have discussed heavy metals (including Zinc, Cadmium, Arsenic, Copper), phthalates, electromagnetic radiation, and temperature in detail. Notably, aberrations in DNA methylation are closely associated with various symptoms of male infertility, and histone modifications and chromatin remodeling are essential for sperm maturation and function. By synthesizing existing literature and experimental data, this narrative review investigates how environmental factors influence male reproductive health through epigenetic mechanisms, thus providing new theoretical foundations and practical guidelines for the early diagnosis and treatment of male infertility.

The characteristics of brain function alterations in patients with chronic prostatitis/chronic pelvic pain syndrome across varying symptom severities evaluated by NIH-CPSI

Background

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a prevalent condition in urology characterized by chronic pain. The pathogenesis of CP/CPPS remains unclear.

Methods

We enrolled 45 eligible CP/CPPS patients and 45 healthy volunteers. We evaluated their resting-state fMRI data using a comprehensive set of parameters, such as Regional Homogeneity (ReHo) and Degree Centrality (DC), to detect brain abnormalities and identify potential correlates with the clinical manifestations of CP/CPPS. We further categorized the patients into subgroups according to their scores of NIH-CPSI to elucidate the brain changes associated with differing symptom severities.

Results

Profound alterations in brain function were observed in patients with CP/CPPS. These changes involved multiple brain regions identified by DC analysis, including the right anterior cingulate cortex (ACC), left inferior frontal opercular cortex, left amygdala, right middle frontal cortex, and bilateral insula. ReHo analysis revealed significant changes in the right thalamus, left inferior frontal triangular cortex, right superior temporal pole, left ACC, and right superior frontal cortex (cluster >20 voxels, GRF correction, p < 0.05). Analysis using ReHo and DC revealed that brain alterations associated with varying symptom severities were localized in pain perception and modulation regions. Specifically, the DC values in the right ACC showed a linear correlation with the severity of symptoms measured by the NIH-CPSI (AUC = 0.9654, p < 0.0001).

Conclusion

In CP/CPPS, we first discovered differences in brain function among patients with varying degrees of severity. The brain alterations of DC in the right ACC might be a potential biomarker for diagnosing and assessing disease severity.

Bifunctional probe propelling multipath strand displacement amplification tandem CRISPR/Cas12a for ultrasensitive and robust assay of DNA methyltransferase activity

BACKGROUND

DNA methylation catalyzed by various DNA methyltransferases (DNA MTases) is one of the important epigenetic regulations in both eukaryotes and prokaryotes. Therefore, the detection of DNA MTase activity is a vital target and direction in the study of methylation-related diseases.

RESULTS

In this study, an ultrasensitive and robust strategy was developed for DNA MTase activity sensing based on bifunctional probe propelling multipath strand displacement amplification and CRISPR/Cas12a techniques. First, a bifunctional hairpin probe (bHpDNA) was designed instead of a conventional single-function probe. In the presence of DNA MTase, the bHpDNA was methylated and cleaved by a restriction endonuclease into two independent primers, both of which bind with the templates to trigger strand displacement amplification and produce the active DNA of CRISPR/Cas12a. Second, annealing-assisted binding instead of free diffusion adhesion was used to improve hybridization efficiency between the primers and templates. Finally, the CRISPR/Cas12a system was used to achieve fluorescence signal output to analyze DNA MTase activity. If targets were absent, there was no signal because no primers were released from the bHpDNA. To verify the reliability of the method, two key DNA MTases, Dam and M. SssI, were analyzed, and their limits of detection were 2.458 × 10-3 and 3.820 × 10-3 U/mL, respectively, which were lower than those of most reported fluorescence methods.

SIGNIFICANCE

This method was successfully used in the evaluation of DNA MTase inhibitors and the detection of DNA MTase activity in complex biological systems with good recoveries and relative standard deviation at low spiked concentrations (0.1-1 U/mL), which all indicate that this method is an ultrasensitive and robust strategy in DNA MTase activity assay and has great potential in biomedical and clinical detection.

A novel SIRT1 activator attenuates neuropathic pain by inhibiting spinal neuronal activation via the SIRT1-mGluR1/5 pathway

Neuropathic pain is a type of pain caused by an injury or disease of the somatosensory nervous system. Currently, there is still absence of effective therapeutic drugs for neuropathic pain, so developing new therapeutic drugs is urgently needed. In the present study, we observed the effect of Comp 6d, a novel silent information regulator 1 (SIRT1) activator synthesized in our laboratory, on neuropathic pain and investigated the mechanisms involved. We found that both intrathecal and intraperitoneal injections of Comp 6d effectively alleviated neuropathic pain induced by chronic constriction injury (CCI) or spared nerve injury (SNI). However, the effect of Comp 6d on neuropathic pain was abolished in SIRT1 knockout mice. These results demonstrated that Comp 6d alleviated neuropathic pain by specifically activating SIRT1 in the spinal cord. Moreover, long-term intraperitoneal injection of Comp 6d had no significant side effects on heart, liver and kidney in SNI mice. Further study showed that the improvement of neuropathic pain by Comp 6d was mediated by the downregulation of mGluR1/5 levels and the subsequent inhibition of spinal neuronal activation. Taken together, the present findings suggest that the novel SIRT1 activator Comp 6d inhibits the activation of spinal cord neurons via the SIRT1-mGluR1/5 pathway, thereby attenuating neuropathic pain. Comp 6d is expected to be an effective therapeutic agent for neuropathic pain.

Chronic Pain and Comorbid Emotional Disorders: Neural Circuitry and Neuroimmunity Pathways

Chronic pain is a multidimensional experience that not only involves persistent nociception but is also frequently accompanied by significant emotional disorders, such as anxiety and depression, which complicate its management and amplify its impact. This review provides an in-depth exploration of the neurobiological mechanisms underlying the comorbidity of chronic pain and emotional disturbances. Key areas of focus include the dysregulation of major neurotransmitter systems (serotonin, gamma-aminobutyric acid, and glutamate) and the resulting functional remodeling of critical neural circuits implicated in pain processing, emotional regulation, and reward. Given the contribution of neuroimmune mechanisms to pain chronicity and mood disorders, we further conducted an in-depth investigation into the role of neuroimmune factors, including resident immune cells, infiltrating immune cells, and the release of inflammatory mediators. This review further discusses current therapeutic strategies, encompassing pharmacological interventions, neuromodulation, and integrative approaches, and emphasizes the necessity of targeted treatments that address both pain and emotional components. Finally, it identifies gaps in the current understanding and outlines future research directions aimed at elucidating the complex interplay between chronic pain and emotional disorders, thereby laying the foundation for more effective and holistic treatment paradigms.

Puerarin improves the comorbidity of chronic pain and depression by binding with Bax and reducing mitochondrial dysfunction

Depression is a common comorbidity of chronic pain. The comorbidity of pain and depression causes longer symptoms and poorer patient prognosis. Periaqueductal gray (PAG) is the key region for the regulation of pain and depression. Puerarin (Pue) is a natural isoflavone compound that has a neuroprotective effect, but the mechanisms on the comorbidity of chronic pain and depression remain unclear. In this study, the spared nerve injury (SNI) produced mechanical allodynia and depressive-like behaviors and elevated the neurological damage in ventrolateral (vl) PAG. Meanwhile, at the 8 weeks following injury, mitochondrial dysfunctions including the dysregulated protein levels, the decreased Mn-SOD activity and the reduced ATP contents were observed in vlPAG of SNI model mice. Pue administration improved mechanical pain, motor coordination, and depression-like behaviors, decreased the neuronal activity and neuroinflammation, and elevated the mitochondrial function in vlPAG. Database analysis and experimental assay showed that Pue bound with Bax at the affinity of 2.4 ± 0.1 μM via D102 residue, and decreased Bax level in vlPAG of mice and in primary astrocytic cells. In addition, Pue also recovered levels of mitochondrial membrane potential and reactive oxygen species, and decreased inflammation in primary astrocytic cells. These results suggest that Pue improves the comorbidity of chronic pain and depression by targeting Bax and reducing mitochondrial dysfunction in vlPAG. This study may provide a theoretical basis for Pue application in improving the comorbidity of chronic pain and depression.

Epigenetic mechanisms of bone cancer pain

The management and treatment of bone cancer pain (BCP) remain significant clinical challenges, imposing substantial economic burdens on patients and society. Extensive research has demonstrated that BCP induces changes in the gene expression of peripheral sensory nerves and neurons, which play crucial roles in the onset and maintenance of BCP. However, our understanding of the epigenetic mechanisms of BCP underlying the transcriptional regulation of pro-nociceptive (such as inflammatory factors and the transient receptor potential family) and anti-nociceptive (such as potassium channels and opioid receptors) genes remains limited. This article reviews the epigenetic regulatory mechanisms in BCP, analyzing the roles of histone modifications, DNA methylation, and noncoding RNAs (ncRNAs) in the expression of pro-nociceptive and anti-nociceptive genes. Finally, we provide a comprehensive view of the functional mechanisms of epigenetic regulation in BCP and explore the potential of these epigenetic molecules as therapeutic targets for BCP.

Pathology of pain and its implications for therapeutic interventions

Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.

Research progress of human key DNA and RNA methylation-related enzymes assay

Gene methylation-related enzymes (GMREs) are disfunction and aberrantly expressed in a variety of cancers, such as lung, gastric, and pancreatic cancers and have important implications for human health. Therefore，it is critical for early diagnosis and therapy of tumor to develop strategies that allow rapid and sensitive quantitative and qualitative detection of GMREs. With the development of modern analytical techniques and the application of various biosensors, there are numerous methods have been developed for analysis of GMREs. Therefore, this paper provides a systematic review of the strategies for level and activity assay of various GMREs including methyltransferases and demethylase. The detection methods mainly involve immunohistochemistry, colorimetry, fluorescence, chemiluminescence, electrochemistry, etc. Then, this review also addresses the coordinated role of various detection probes, novel nanomaterials, and signal amplification methods. The aim is to highlight potential challenges in the present field, to expand the analytical application of GMREs detection strategies, and to meet the urgent need for future disease diagnosis and intervention.

Impaired synaptic plasticity and decreased glutamatergic neuron excitability induced by SIRT1/BDNF downregulation in the hippocampal CA1 region are involved in postoperative cognitive dysfunction

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication after anesthesia/surgery, especially among elderly patients, and poses a significant threat to their postoperative quality of life and overall well-being. While it is widely accepted that elderly patients may experience POCD following anesthesia/surgery, the exact mechanism behind this phenomenon remains unclear. Several studies have indicated that the interaction between silent mating type information regulation 2 homologue 1 (SIRT1) and brain-derived neurotrophic factor (BDNF) is crucial in controlling cognitive function and is strongly linked to neurodegenerative disorders. Hence, this research aims to explore how SIRT1/BDNF impacts cognitive decline caused by anesthesia/surgery in aged mice.

METHODS

Open field test (OFT) was used to determine whether anesthesia/surgery affected the motor ability of mice, while the postoperative cognitive function of 18 months old mice was evaluated with Novel object recognition test (NORT), Object location test (OLT) and Fear condition test (FC). The expressions of SIRT1 and other molecules were analyzed by western blot and immunofluorescence staining. The hippocampal synaptic plasticity was detected by Golgi staining and Long-term potentiation (LTP). The effects of SIRT1 and BDNF overexpression as well as chemogenetic activation of glutamatergic neurons in hippocampal CA1 region of 18 months old vesicular glutamate transporter 1 (VGLUT1) mice on POCD were further investigated.

RESULTS

The research results revealed that older mice exhibited cognitive impairment following intramedullary fixation of tibial fracture. Additionally, a notable decrease in the expression of SIRT1/BDNF and neuronal excitability in hippocampal CA1 glutamatergic neurons was observed. By increasing levels of SIRT1/BDNF or enhancing glutamatergic neuron excitability in the CA1 region, it was possible to effectively mitigate synaptic plasticity impairment and ameliorate postoperative cognitive dysfunction.

CONCLUSIONS

The decline in SIRT1/BDNF levels leading to changes in synaptic plasticity and neuronal excitability in older mice could be a significant factor contributing to cognitive impairment after anesthesia/surgery.

Nerolidol reduces depression-like behavior in mice and suppresses microglia activation by down-regulating DNA methyltransferase 1

Modern medicine has unveiled that essential oil made from Aquilaria possesses sedative and hypnotic effects. Among the chemical components in Aquilaria, nerolidol, a natural sesquiterpene alcohol, has shown promising effects. This study aimed to unravel the potential of nerolidol in treating depression. Chronic unpredictable mild stress (CUMS) was utilized to induce depression-like behavior in mice, and open field test, sucrose preference, and tail suspension test was conducted. The impacts of nerolidol on the inflammatory response, microglial activation, and DNA methyltransferase 1 (DNMT1) were assessed. To study the regulatory role of DNMT1, lipopolysaccharide (LPS) was used to treat BV2 cells, followed by the evaluation of cell viability and DNMT1 level. Additionally, the influence of DNMT1 overexpression on BV2 cell activation was determined. Behavioral analysis revealed that nerolidol reduced depression-like behavior in mice. Nerolidol reduced the levels of inflammatory factors and microglial activation caused by CUMS. Nerolidol treatment was found to reduce DNMT1 levels in mouse brain tissue and it also decrease the LPS-induced increase in DNMT1 levels in BV2 cells. DNMT1 overexpression reversed the impacts of nerolidol on the inflammation response and cell activation. This study underscores the potential of nerolidol in reducing CUMS-induced depressive-like behavior and inhibiting microglial activation by downregulating DNMT1. These findings offer valuable insights into the potential of nerolidol as a therapeutic option for depression.

Impaired oxytocin signaling in the central amygdala in rats with chronic heart failure

Aims

Heart failure (HF) patients often suffer from cognitive decline, depression, and mood impairments, but the molecular signals and brain circuits underlying these effects remain elusive. The hypothalamic neuropeptide oxytocin (OT) is critically involved in the regulation of mood, and OTergic signaling in the central amygdala (CeA) is a key mechanism controlling emotional responses including anxiety-like behaviors. Based on this, we used in this study a well-established ischemic rat HF model and aimed to study alterations in the hypothalamus-to-CeA OTergic circuit.

Methods and Results

To study potential HF-induced changes in the hypothalamus-to-CeA OTertic circuit, we combined patch-clamp electrophysiology, immunohistochemical analysis, RNAScope assessment of OTR mRNA, brain region-specific stereotaxic injections of viral vectors and retrograde tracing, optogenetic stimulation and OT biosensors in the ischemic HF model. We found that most of OTergic innervation of the central amygdala (CeA) originated from the hypothalamic supraoptic nucleus (SON). While no differences in the numbers of SON→CeA OTertic neurons (or their OT content) was observed between sham and HF rats, we did observe a blunted content and release of OT from axonal terminals within the CeA. Moreover, we report downregulation of neuronal and astrocytic OT receptors, and impaired OTR-driven GABAergic synaptic activity within the CeA microcircuit of rats with HF.

Conclusions

Our study provides first evidence that HF rats display various perturbations in the hypothalamus-to-amygdala OTergic circuit, and lays the foundation for future translational studies targeting either the OT system or GABAergic amygdala GABA microcircuit to ameliorate depression or mood impairments in rats or patients with chronic HF.