Painful diabetic neuropathy is a common complication of diabetes produced by mechanisms that as yet are incompletely defined. The aim of this study was to investigate the roles of nuclear factor-κB (NF-κB) in the regulation of purinergic receptor P2X ligand-gated ion channel 3 (P2X3R) plasticity in dorsal root ganglion (DRG) neurons of rats with painful diabetes. Here, we showed that hindpaw pain hypersensitivity in streptozocin-induced diabetic rats was attenuated by treatment with purinergic receptor antagonist suramin or A-317491. The expression and function of P2X3Rs was markedly enhanced in hindpaw-innervated DRG neurons in diabetic rats. The CpG (cytosine guanine dinucleotide) island in the p2x3r gene promoter region was significantly demethylated, and the expression of DNA methyltransferase 3b was remarkably downregulated in DRGs in diabetic rats. The binding ability of p65 (an active form of NF-κB) with the p2x3r gene promoter region and p65 expression were enhanced significantly in diabetes. The inhibition of p65 signaling using the NF-κB inhibitor pyrrolidine dithiocarbamate or recombinant lentiviral vectors designated as lentiviral vector-p65 small interfering RNA remarkably suppressed P2X3R activities and attenuated diabetic pain hypersensitivity. Insulin treatment significantly attenuated pain hypersensitivity and suppressed the expression of p65 and P2X3Rs. Our findings suggest that the p2x3r gene promoter DNA demethylation and enhanced interaction with p65 contributes to P2X3R sensitization and diabetic pain hypersensitivity.

Nuclear factor-kappa B (NF-κB) signaling is implicated in both cancer development and inflammation processes. However, the roles and mechanisms of NF-κB signaling in the development of cancer-induced pain (CIP) remain unknown. This study was designed to investigate the roles of the p65 subunit of NF-κB in regulation of the purinergic receptor (P2X3R) plasticity in dorsal root ganglion (DRG) of CIP rats. We showed here that tumor cell injection produced mechanical and thermal hyperalgesia, and an enhanced body weight–bearing difference, which was correlated with an upregulation of p65 and P2X3R expression in lumber DRGs and a potentiation of ATP-evoked responses of tibia-innervating DRG neurons. Inhibition of NF-κB signaling using p65 inhibitor pyrrolidine dithiocarbamate, BAY-11-7082, or lentiviral-p65 short-hairpin RNA significantly attenuated CIP and reversed the activities of P2X3R. Interestingly, tumor cell injection led to a significant demethylation of CpG island in p2x3r gene promoter and enhanced ability of p65 to bind the promoter of p2x3r gene. Our findings suggest that upregulation of P2X3R expression was mediated by the enhanced binding capability of p65 with demethylated promoter of p2x3r gene, thus contributing to CIP. NF-κBp65 might be a potential target for treating CIP, a neuropathic pain generated by tumor cell–induced injury to nerves that innervate the skin.

Patients with long-standing diabetes frequently demonstrate gastric hypersensitivity with an unknown mechanism. The present study was designed to investigate roles for nuclear factor-κB (NF-κB) and the endogenous H₂S-producing enzyme cystathionine-β-synthetase (CBS) signaling pathways by examiningcbsgene methylation status in adult rats with diabetes. Intraperitoneal injection of streptozotocin (STZ) produced gastric hypersensitivity in female rats in response to gastric balloon distention. Treatment with the CBS inhibitor aminooxyacetic acid significantly attenuated STZ-induced gastric hypersensitivity in a dose-dependent fashion. Aminooxyacetic acid treatment also reversed hyperexcitability of gastric-specific dorsal root ganglion (DRG) neurons labeled by the dye DiI in diabetic rats. Conversely, the H₂S donor NaHS enhanced neuronal excitability of gastric DRG neurons. Expression of CBS and p65 were markedly enhanced in gastric DRGs in diabetic rats. Blockade of NF-κB signaling using pyrrolidine dithiocarbamate reversed the upregulation of CBS expression. Interestingly, STZ treatment led to a significant demethylation of CpG islands in thecbsgene promoter region, as determined by methylation-specific PCR and bisulfite sequencing. STZ treatment also remarkably downregulated the expression of DNA methyltransferase 3a and 3b. More importantly, STZ treatment significantly enhanced the ability ofcbsto bind DNA at the p65 consensus site, as shown by chromatin immunoprecipitation assays. Our findings suggest that upregulation ofcbsexpression is attributed tocbspromoter DNA demethylation and p65 activation and that the enhanced interaction of thecbsgene and p65 contributes to gastric hypersensitivity in diabetes. This finding may guide the development and evaluation of new treatment modalities for patients with diabetic gastric hypersensitivity.

Chronic visceral pain is a major challenge for both patients and health providers. Although the central sensitization of the brain is thought to play an important role in the development of visceral pain, the detailed neural circuits remain largely unknown. Using a well-established chronic visceral hypersensitivity model induced by neonatal maternal deprivation (NMD) in male mice, we identified a distinct pathway whereby the claustrum (CL) glutamatergic neuron projecting to the anterior cingulate cortex (ACC) is critical for visceral pain but not for CFA-evoked inflammatory pain. By a combination ofin vivocircuit-dissecting extracellular electrophysiological approaches and visceral pain related electromyographic (EMG) recordings, we demonstrated that optogenetic inhibition of CL glutamatergic activity suppressed the ACC neural activity and visceral hypersensitivity of NMD mice whereas selective activation of CL glutamatergic activity enhanced the ACC neural activity and evoked visceral pain of control mice. Further, optogenetic studies demonstrate a causal link between such neuronal activity and visceral pain behaviors. Chemogenetic activation or inhibition of ACC neural activities reversed the effects of optogenetic manipulation of CL neural activities on visceral pain responses. Importantly, molecular detection showed that NMD significantly enhances the expression of NMDA receptors and activated CaMKIIα in the ACC postsynaptic density (PSD) region. Together, our data establish a functional role for CL→ACC glutamatergic neurons in gating visceral pain, thus providing a potential treatment strategy for visceral pain.SIGNIFICANCE STATEMENTStudies have shown that sensitization of anterior cingulate cortex (ACC) plays an important role in chronic pain. However, it is as yet unknown whether there is a specific brain region and a distinct neural circuit that helps the ACC to distinguish visceral and somatic pain. The present study demonstrates that claustrum (CL) glutamatergic neurons maybe responding to colorectal distention (CRD) rather than somatic stimulation and that a CL glutamatergic projection to ACC glutamatergic neuron regulates visceral pain in mice. Furthermore, excessive NMDA receptors and overactive CaMKIIα in the ACC postsynaptic density (PSD) region were observed in mice with chronic visceral pain. Together, these findings reveal a novel neural circuity underlying the central sensitization of chronic visceral pain.

This study aimed to assess the effects of cognitive behavioral therapy on the psychological and physiological health of rheumatoid arthritis patients. An extensive literature search was conducted, using the PubMed, Web of Science, Cochrane Library, Embase, CNKI Scholar, WanFang, and VIP databases, from inception to December2018. The quality of the studies was evaluated by 2 independent authors, according to the basic criteria provided by the Cochrane Handbook for evaluating randomized trials. Meta-analysis was performed with Review Manager 5.3. Six randomized controlled trials met the inclusion criteria of the current study. Using standard mean differences (SMD) and 95% confidence intervals (CI), our results showed that cognitive behavioral therapy could significantly reduce levels of anxiety (SMD = −0.30, 95% CI [−0.52, −0.09], P= 0.005) and depression (SMD = −0.48, 95% CI [−0.70, −0.27], P< 0.00001), and relieve fatigue symptoms (SMD = −0.35, 95% CI [−0.60, −0.10], P= 0.006) in rheumatoid arthritis patients.This is the first known assessment of the efficacy of cognitive behavioral therapy on rheumatoid arthritis patients using meta-analysis. Large-scale randomized controlled trials need to be implemented to further explore this issue.

Chronic visceral pain (CVP) often accompanies emotional disorders. However, the lack of suitable animal models has hindered research into their underlying molecular and neural circuitry mechanisms. Early-life stress is a key factor in developing both visceral hypersensitivity and emotional disorders, yet its pathological mechanisms are not well understood. This study showed that adult offspring of prenatal maternal stress (PMS)-exposed mice exhibited visceral hypersensitivity and anxiety-like behaviors. Glutamatergic neurons in the anterior paraventricular thalamus (aPVT) responded to visceral pain, while those in the posterior PVT (pPVT) were more responsive to anxiety. The aPVT-basolateral amygdala (BLA) and pPVT-central amygdala (CeA) circuits regulated CVP and anxiety, respectively. Notably, increased Cacna1e expression in aPVT enhanced both visceral pain and anxiety, while Grin2a upregulation in pPVT facilitated only anxiety. These findings highlight the distinct roles of aPVT^Glu-BLA^Glu-CeA^GABA and pPVT^Glu-CeA^GABA circuits, providing insights for therapeutic approaches in CVP and anxiety comorbidity.