In-depth analysis reveals complex molecular aetiology in a cohort of idiopathic cerebral palsy.

Cerebral palsy is the most prevalent physical disability in children; however, its inherent molecular mechanisms remain unclear. In the present study, we performed in-depth clinical and molecular analysis on 120 idiopathic cerebral palsy families, and identified underlying detrimental genetic variants in 45% of these patients. In addition to germline variants, we found disease-related postzygotic mutations in ∼6.7% of cerebral palsy patients. We found that patients with more severe motor impairments or a comorbidity of intellectual disability had a significantly higher chance of harbouring disease-related variants. By a compilation of 114 known cerebral-palsy-related genes, we identified characteristic features in terms of inheritance and function, from which we proposed a dichotomous classification system according to the expression patterns of these genes and associated cognitive impairments. In two patients with both cerebral palsy and intellectual disability, we revealed that the defective TYW1, a tRNA hypermodification enzyme, caused primary microcephaly and problems in motion and cognition by hindering neuronal proliferation and migration. Furthermore, we developed an algorithm and demonstrated in mouse brains that this malfunctioning hypermodification specifically perturbed the translation of a subset of proteins involved in cell cycling. This finding provided a novel and interesting mechanism for congenital microcephaly. In another cerebral palsy patient with normal intelligence, we identified a mitochondrial enzyme GPAM, the hypomorphic form of which led to hypomyelination of the corticospinal tract in both human and mouse models. In addition, we confirmed that the aberrant Gpam in mice perturbed the lipid metabolism in astrocytes, resulting in suppressed astrocytic proliferation and a shortage of lipid contents supplied for oligodendrocytic myelination. Taken together, our findings elucidate novel aspects of the aetiology of cerebral palsy and provide insights for future therapeutic strategies.

Termination of cell-type specification gene programs by the miR-183 cluster determines the population sizes of low-threshold mechanosensitive neurons.

Touch and mechanical sensations require the development of several different kinds of sensory neurons dedicated to respond to certain types of mechanical stimuli. The transcription factor Shox2 (short stature homeobox 2) is involved in the generation of TRKB+ low-threshold mechanoreceptors (LTMRs), but mechanisms terminating this program and allowing alternative fates are unknown. Here, we show that the conditional loss of the miR-183-96-182 cluster in mouse leads to a failure of extinction of Shox2 during development and an increase in the proportion of Aδ LTMRs (TRKB+/NECAB2+) neurons at the expense of Aß slowly adapting (SA)-LTMRs (TRKC+/Runx3-) neurons. Conversely, overexpression of miR-183 cluster that represses Shox2 expression, or loss of Shox2, both increase the Aß SA-LTMRs population at the expense of Aδ LTMRs. Our results suggest that the miR-183 cluster determines the timing of Shox2 expression by direct targeting during development, and through this determines the population sizes of Aδ LTMRs and Aß SA-LTMRs.

Spinal Cord Stimulation and Treatment of Peripheral or Central Neuropathic Pain: Mechanisms and Clinical Application.

Spinal cord stimulation (SCS) as an evidence-based interventional treatment has been used and approved for clinical use in a variety of pathological states including peripheral neuropathic pain; however, until now, it has not been used for the treatment of spinal cord injury- (SCI-) induced central neuropathic pain. This paper reviews the underlying mechanisms of SCS-induced analgesia and its clinical application in the management of peripheral and central neuropathic pain. Evidence from recent research publications indicates that nociceptive processing at peripheral and central sensory systems is thought to be modulated by SCS through (i) inhibition of the ascending nociceptive transmission by the release of analgesic neurotransmitters such as GABA and endocannabinoids at the spinal dorsal horn; (ii) facilitation of the descending inhibition by release of noradrenalin, dopamine, and serotonin acting on their receptors in the spinal cord; and (iii) activation of a variety of supraspinal brain areas related to pain perception and emotion. These insights into the mechanisms have resulted in the clinically approved use of SCS in peripheral neuropathic pain states like Complex Regional Pain Syndrome (CRPS) and Failed Back Surgery Syndrome (FBSS). However, the mechanisms underlying SCS-induced pain relief in central neuropathic pain are only partly understood, and more research is needed before this therapy can be implemented in SCI patients with central neuropathic pain.

MiR-146a alleviates inflammatory bowel disease in mice through systematic regulation of multiple genetic networks.

Introduction: Inflammatory bowel disease (IBD) is a chronic disease involving multiple genes, and the current available targeted drugs for IBD only deliver moderate efficacy. Whether there is a single gene that systematically regulates IBD is not yet known. MiR-146a plays a pivotal role in repression of innate immunity, but its function in the intestinal inflammation is sort of controversy, and the genetic regulatory networks regulated by miR-146a in IBD has not been revealed. Methods: RT-qPCR was employed to detect the expression of miR-146a in IBD patients and in a mouse IBD model induced by dextran sulfate sodium (DSS), and then we generated a miR-146a knock-out mouse line with C57/Bl6N background. The disease activity index was scored in DSS-treated miR-146a deficiency mice and their wild type (WT) littermates. Bulk RNA-sequencing, RT-qPCR and immunostaining were done to illustrate the downstream genetic regulatory networks of miR-146a in flamed colon. Finally, the modified miR-146a mimics were used to treat DSS-induced IBD in miR-146a knock-out and WT IBD mice. Results: We showed that the expression of miR-146a in the colon was elevated in dextran sulfate sodium (DSS)-induced IBD mice and patients with IBD. DSS induced dramatic body weight loss and more significant rectal bleeding, shorter colon length, and colitis in miR-146a knock-out mice than WT mice. The miR-146a mimics alleviated DSS-induced symptoms in both miR-146a-/- and WT mice. Further RNA sequencing illustrated that the deficiency of miR-146a de-repressed majority of DSS-induced IBD-related genes that cover multiple genetic regulatory networks in IBD, and supplementation with miR-146a mimics inhibited the expression of many IBD-related genes. Quantitative RT-PCR or immunostaining confirmed that Ccl3, Saa3, Csf3, Lcn2, Serpine1, Serpine2, MMP3, MMP8, MMP10, IL1A, IL1B, IL6, CXCL2, CXCL3, S100A8, S100A9, TRAF6, P65, p-P65, and IRAK1 were regulated by miR-146a in DSS induced IBD. Among them, MMP3, MMP10, IL6, IL1B, S100A8, S100A9, SERPINE1, CSF3, and IL1A were involved in the active stage of IBD in humans. Discussion: Our date demonstrated that miR-146a acts as a top regulator in C57/BL6N mice to systematically repress multiple genetic regulatory networks involved in immune response of intestine to environment factors, and combinatory treatment with miR-146a-5p and miR-146a-3p mimics attenuates DSS-induced IBD in mice through down-regulating multiple genetic regulatory networks which were increased in colon tissue from IBD patients. Our findings suggests that miR-146a is a top inhibitor of IBD, and that miR-146a-5p and miR-146a-3p mimics might be potential drug for IBD.

A unilateral negative feedback loop between miR-200 microRNAs and Sox2/E2F3 controls neural progenitor cell-cycle exit and differentiation.

MicroRNAs have emerged as key posttranscriptional regulators of gene expression during vertebrate development. We show that the miR-200 family plays a crucial role for the proper generation and survival of ventral neuronal populations in the murine midbrain/hindbrain region, including midbrain dopaminergic neurons, by directly targeting the pluripotency factor Sox2 and the cell-cycle regulator E2F3 in neural stem/progenitor cells. The lack of a negative regulation of Sox2 and E2F3 by miR-200 in conditional Dicer1 mutants (En1(+/Cre); Dicer1(flox/flox) mice) and after miR-200 knockdown in vitro leads to a strongly reduced cell-cycle exit and neuronal differentiation of ventral midbrain/hindbrain (vMH) neural progenitors, whereas the opposite effect is seen after miR-200 overexpression in primary vMH cells. Expression of miR-200 is in turn directly regulated by Sox2 and E2F3, thereby establishing a unilateral negative feedback loop required for the cell-cycle exit and neuronal differentiation of neural stem/progenitor cells. Our findings suggest that the posttranscriptional regulation of Sox2 and E2F3 by miR-200 family members might be a general mechanism to control the transition from a pluripotent/multipotent stem/progenitor cell to a postmitotic and more differentiated cell.

Ectopic expression of Nav1.7 in spinal dorsal horn neurons induced by NGF contributes to neuropathic pain in a mouse spinal cord injury model.

Neuropathic pain (NP) induced by spinal cord injury (SCI) often causes long-term disturbance for patients, but the mechanisms behind remains unclear. Here, our study showed SCI-induced ectopic expression of Nav1.7 in abundant neurons located in deep and superficial laminae layers of the spinal dorsal horn (SDH) and upregulation of Nav1.7 expression in dorsal root ganglion (DRG) neurons in mice. Pharmacologic studies demonstrated that the efficacy of the blood-brain-barrier (BBB) permeable Nav1.7 inhibitor GNE-0439 for attenuation of NP in SCI mice was significantly better than that of the BBB non-permeable Nav1.7 inhibitor PF-05089771. Moreover, more than 20% of Nav1.7-expressing SDH neurons in SCI mice were activated to express FOS when there were no external stimuli, suggesting that the ectopic expression of Nav1.7 made SDH neurons hypersensitive and Nav1.7-expressing SDH neurons participated in central sensitization and in spontaneous pain and/or walking-evoked mechanical pain. Further investigation showed that NGF, a strong activator of Nav1.7 expression, and its downstream JUN were upregulated after SCI in SDH neurons with similar distribution patterns and in DRG neurons too. In conclusion, our findings showed that the upregulation of Nav1.7 was induced by SCI in both SDH and DRG neurons through increased expression of NGF/JUN, and the inhibition of Nav1.7 in both peripheral and spinal neurons alleviated mechanical pain in SCI mice. These data suggest that BBB permeable Nav1.7 blockers might relieve NP in patients with SCI and that blocking the upregulation of Nav1.7 in the early stage of SCI via selective inhibition of the downstream signaling pathways of NGF or Nav1.7-targeted RNA drugs could be a strategy for therapy of SCI-induced NP.

Pitx3 is a critical mediator of GDNF-induced BDNF expression in nigrostriatal dopaminergic neurons.

Pitx3 is a critical homeodomain transcription factor for the proper development and survival of mesodiencephalic dopaminergic (mdDA) neurons in mammals. Several variants of this gene have been associated with human Parkinson's disease (PD), and lack of Pitx3 in mice causes the preferential loss of substantia nigra pars compacta (SNc) mdDA neurons that are most affected in PD. It is currently unclear how Pitx3 activity promotes the survival of SNc mdDA neurons and which factors act upstream and downstream of Pitx3 in this context. Here we show that a transient expression of glial cell line-derived neurotrophic factor (GDNF) in the murine ventral midbrain (VM) induces transcription of Pitx3 via NF-κB-mediated signaling, and that Pitx3 is in turn required for activating the expression of brain-derived neurotrophic factor (BDNF) in a rostrolateral (SNc) mdDA neuron subpopulation during embryogenesis. The loss of BDNF expression correlates with the increased apoptotic cell death of this mdDA neuronal subpopulation in Pitx3(-/-) mice, whereas treatment of VM cell cultures with BDNF augments the survival of the Pitx3(-/-) mdDA neurons. Most importantly, only BDNF but not GDNF protects mdDA neurons against 6-hydroxydopamine-induced cell death in the absence of Pitx3. As the feedforward regulation of GDNF, Pitx3, and BDNF expression also persists in the adult rodent brain, our data suggest that the disruption of the regulatory interaction between these three factors contributes to the loss of mdDA neurons in Pitx3(-/-) mutant mice and perhaps also in human PD.

MicroRNA-96 is required to prevent allodynia by repressing voltage-gated sodium channels in spinal cord.

Voltage-gated sodium channels (Navs) 1.7, 1.8, and 1.9 are predominately expressed in peripheral sensory neurons and are critical for action potential propagation in nociceptors. Unexpectedly, we found that expression of SCN9A, SCN10A, SCN11A, and SCN2A, the alpha subunit of Nav1.7, Nav1.8, Nav1.9 and Nav1.2, respectively, are up-regulated in spinal dorsal horn (SDH) neurons of miR-96 knockout mice. These mice also have de-repression of CACNA2D1/2 in DRG and display thermal and mechanical allodynia that could be attenuated by intrathecal or intraperitoneal injection of Nav1.7 or Nav1.8 blockers or Gabapentin. Moreover, Gad2::CreERT2 conditional miR-96 knockout mice phenocopied global knockout mice, implicating inhibitory neurons; nerve injury induced significant loss of miR-96 in SDH GABAergic and Glutamatergic neurons in mice which negatively correlated to up-regulation of Nav1.7, Nav1.8, Nav1.9 and Scn2a, this dis-regulation of miR-96 and Navs in SDH neurons contributed to neuropathic pain which can be alleviated by intrathecal injection of Nav1.7 or Nav1.8 blockers. In conclusion, miR-96 is required to avoid allodynia through limiting the expression of VGCCs and Navs in DRG and Navs in SDH in naïve and nerve injury-induced neuropathic pain mice. Our findings suggest that central nervous system penetrating Nav1.7 and Nav1.8 blockers may be efficacious for pain relief.

Arhgef2 regulates neural differentiation in the cerebral cortex through mRNA m6A-methylation of Npdc1 and Cend1.

N 6-methyladenosine (m6A) is emerging as a vital factor regulating neural differentiation. Here, we report that deficiency of Arhgef2, a novel cause of a neurodevelopmental disorder we identified recently, impairs neurogenesis, neurite outgrowth, and synaptic formation by regulating m6A methylation. Arhgef2 knockout decreases expression of Mettl14 and total m6A level significantly in the cerebral cortex. m6A sequencing reveals that loss of Arhgef2 reduces m6A methylation of 1,622 mRNAs, including Npdc1 and Cend1, which are both strongly associated with cell cycle exit and terminal neural differentiation. Arhgef2 deficiency decreases m6A methylations of the Npdc1 and Cend1 mRNAs via down-regulation of Mettl14, and thereby inhibits the translation of Npdc1 and nuclear export of Cend1 mRNAs. Overexpression of Mettl14, Npdc1, and Cend1 rescue the abnormal phenotypes in Arhgef2 knockout mice, respectively. Our study provides a critical insight into a mechanism by which defective Arhgef2 mediates m6A-tagged target mRNAs to impair neural differentiation.

Exercise for Neuropathic Pain: A Systematic Review and Expert Consensus.

Background: Neuropathic pain (NP), a severe and disruptive symptom following many diseases, normally restricts patients' physical functions and leads to anxiety and depression. As an economical and effective therapy, exercise may be helpful in NP management. However, few guidelines and reviews focused on exercise therapy for NP associated with specific diseases. The study aimed to summarize the effectiveness and efficacy of exercise for various diseases with NP supported by evidence, describe expert recommendations for NP from different causes, and inform policymakers of the guidelines. Design: A systematic review and expert consensus. Methods: A systematic search was conducted in PubMed. We included systematic review and meta-analysis, randomized controlled trials (RCTs), which assessed patients with NP. Studies involved exercise intervention and outcome included pain intensity at least. Physiotherapy Evidence Database and the Assessment of Multiple Systematic reviews tool were used to grade the quality assessment of the included RCTs and systematic reviews, respectively. The final grades of recommendation were based on strength of evidence and a consensus discussion of results of Delphi rounds by the Delphi consensus panel including 21 experts from the Chinese Association of Rehabilitation Medicine. Results: Eight systematic reviews and 21 RCTs fulfilled all of the inclusion criteria and were included, which were used to create the 10 evidence-based consensus statements. The 10 expert recommendations regarding exercise for NP symptoms were relevant to the following 10 different diseases: spinal cord injury, stroke, multiple sclerosis, Parkinson's disease, cervical radiculopathy, sciatica, diabetic neuropathy, chemotherapy-induced peripheral neuropathy, HIV/AIDS, and surgery, respectively. The exercise recommended in the expert consensus involved but was not limited to muscle stretching, strengthening/resistance exercise, aerobic exercise, motor control/stabilization training and mind-body exercise (Tai Chi and yoga). Conclusions: Based on the available evidence, exercise is helpful to alleviate NP intensity. Therefore, these expert consensuses recommend that proper exercise programs can be considered as an effective alternative treatment or complementary therapy for most patients with NP. The expert consensus provided medical staff and policymakers with applicable recommendations for the formulation of exercise prescription for NP. This consensus statement will require regular updates after five-ten years.

Dose-Dependent and Subset-Specific Regulation of Midbrain Dopaminergic Neuron Differentiation by LEF1-Mediated WNT1/b-Catenin Signaling.

The mesodiencephalic dopaminergic (mdDA) neurons, including the nigrostriatal subset that preferentially degenerates in Parkinson's Disease (PD), strongly depend on an accurately balanced Wingless-type MMTV integration site family member 1 (WNT1)/beta-catenin signaling pathway during their development. Loss of this pathway abolishes the generation of these neurons, whereas excessive WNT1/b-catenin signaling prevents their correct differentiation. The identity of the cells responding to this pathway in the developing mammalian ventral midbrain (VM) as well as the precise progression of WNT/b-catenin action in these cells are still unknown. We show that strong WNT/b-catenin signaling inhibits the differentiation of WNT/b-catenin-responding mdDA progenitors into PITX3+ and TH+ mdDA neurons by repressing the Pitx3 gene in mice. This effect is mediated by RSPO2, a WNT/b-catenin agonist, and lymphoid enhancer binding factor 1 (LEF1), an essential nuclear effector of the WNT/b-catenin pathway, via conserved LEF1/T-cell factor binding sites in the Pitx3 promoter. LEF1 expression is restricted to a caudolateral mdDA progenitor subset that preferentially responds to WNT/b-catenin signaling and gives rise to a fraction of all mdDA neurons. Our data indicate that an attenuation of WNT/b-catenin signaling in mdDA progenitors is essential for their correct differentiation into specific mdDA neuron subsets. This is an important consideration for stem cell-based regenerative therapies and in vitro models of neuropsychiatric diseases.

Pitx3-transfected astrocytes secrete brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor and protect dopamine neurons in mesencephalon cultures.

The transcription factor Pitx3 is crucial for the development and differentiation of dopamine (DA) neurons. Our previous work has shown the Pitx3 can up-regulate the expression of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in neuroblastoma cell line SH-SY5Y. Primary astrocytes are the major nonneuronal cells and can be easily modified genetically to deliver therapeutic molecules into the brain, so we investigated whether Pitx3 can increase the expression and secretion of BDNF and GDNF in primary astrocytes. We first transfected Pitx3 plasmid in purified rat astrocytes and collected the conditioned medium (CM) from the Pitx3-transfected cultures, and then we measured the BDNF and GDNF levels from the CM and tested the protective effect of the CM against rotenone-induced DA neuron injury in ventral mesencephalon (VM) cultures. We found that the BDNF and GDNF levels were 1.4-fold and 1.5-fold higher in the CM from Pitx3-transfected astrocytes than empty vectors-transfected controls. Incubation with the CM from Pitx3-transfected astrocytes significantly attenuated the rotenone-induced DA neuron injury, and such protection can be significantly blocked by preincubation with antibodies against either BDNF or GDNF, whereas preincubation with purified BDNF or GDNF replicated the neuroprotection against rotenone-induced injury in VM cultures. These results demonstrate that Pitx3-transfection in astrocytes can up-regulate BDNF and GDNF expression and produce protective benefit to DA neurons, which might be a potential therapeutic alternative for Parkinson's disease.

A Zeb2-miR-200c loop controls midbrain dopaminergic neuron neurogenesis and migration.

Zeb2 is a homeodomain transcription factor that plays pleiotropic functions during embryogenesis, but its role for midbrain dopaminergic (mDA) neuron development is unknown. Here we report that Zeb2 is highly expressed in progenitor cells in the ventricular zone of the midbrain floor plate and downregulated in postmitotic neuroblasts. Functional experiments show that Zeb2 expression in the embryonic ventral midbrain is dynamically regulated by a negative feedback loop that involves miR-200c. We also find that Zeb2 overexpression reduces the levels of CXCR4, NR4A2, and PITX3 in the developing ventral midbrain in vivo, resulting in migration and mDA differentiation defects. This phenotype was recapitulated by miR-200c knockdown, suggesting that the Zeb2-miR-200c loop prevents the premature differentiation of mDA progenitors into postmitotic cells and their migration. Together, our study establishes Zeb2 and miR-200c as critical regulators that maintain the balance between mDA progenitor proliferation and neurogenesis.

Ca2+-binding protein NECAB2 facilitates inflammatory pain hypersensitivity.

Pain signals are transmitted by multisynaptic glutamatergic pathways. Their first synapse between primary nociceptors and excitatory spinal interneurons gates the sensory load. In this pathway, glutamate release is orchestrated by Ca2+-sensor proteins, with N-terminal EF-hand Ca2+-binding protein 2 (NECAB2) being particular abundant. However, neither the importance of NECAB2+ neuronal contingents in dorsal root ganglia (DRGs) and spinal cord nor the function determination by NECAB2 has been defined. A combination of histochemical analyses and single-cell RNA-sequencing showed NECAB2 in small- and medium-sized C- and Aδ D-hair low-threshold mechanoreceptors in DRGs, as well as in protein kinase C γ excitatory spinal interneurons. NECAB2 was downregulated by peripheral nerve injury, leading to the hypothesis that NECAB2 loss of function could limit pain sensation. Indeed, Necab2-/- mice reached a pain-free state significantly faster after peripheral inflammation than did WT littermates. Genetic access to transiently activated neurons revealed that a mediodorsal cohort of NECAB2+ neurons mediates inflammatory pain in the mouse spinal dorsal horn. Here, besides dampening excitatory transmission in spinal interneurons, NECAB2 limited pronociceptive brain-derived neurotrophic factor (BDNF) release from sensory afferents. Hoxb8-dependent reinstatement of NECAB2 expression in Necab2-/- mice then demonstrated that spinal and DRG NECAB2 alone could control inflammation-induced sensory hypersensitivity. Overall, we identify NECAB2 as a critical component of pronociceptive pain signaling, whose inactivation offers substantial pain relief.

Overexpression of pitx3 upregulates expression of BDNF and GDNF in SH-SY5Y cells and primary ventral mesencephalic cultures.

The transcription factor Pitx3 plays an important role in the development of midbrain to promote the growth and differentiation of dopamine neurons. The present study has demonstrated that overexpression of Pitx3 in SH-SY5Y cells and primary ventral mesencephalic (VM) cultures significantly increased the mRNA levels of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), and remarkably elevated the protein levels of these two neurotrophic factors. Our data provide the first evidence that pitx3-expressing cells are able to upregulate the expression of BDNF and GDNF. Therefore, Pitx3 might be a good target for the treatment of Parkinson's disease.

Proteasome inhibitor lactacystin disturbs the intracellular calcium homeostasis of dopamine neurons in ventral mesencephalic cultures.

Ubiquitin proteasome system (UPS) impairment has been implicated in the pathology of Parkinson's disease, but the mechanisms underlying the UPS impairment-induced dopamine (DA) neuron degeneration remain obscure. To test whether calcium homeostasis disturbance is involved in the DA neuronal injury resulting from UPS impairment, we treated the primary ventral mesencephalic (VM) cultures with the proteasome inhibitor lactacystin, and observed its effects on the expression of the gene Homer 1a that is related to calcium homeostasis, and the intracellular free calcium ([Ca2+]i) levels as well as the DA neuron survival. We also investigated a possible role of the L-type voltage dependent calcium channels (L-VDCC) in these events. We found that the lactacystin exposure induced the Homer 1a expression, lowered the [Ca2+]i levels, reduced the depolarization-induced calcium entry and DA release in the VM cultures, and caused a significant DA neuron loss. Activation of L-VDCC by potassium chloride or its agonists alleviated the effects of lactacystin on the [Ca2+]i levels and promoted DA neuron survival, whereas L-VDCC antagonists blocked the depolarization-mediated neuroprotective effect, and at high concentrations the L-VDCC antagonists aggravated the lactacystin-induced DA neuronal injury. These results indicate that calcium homeostasis disturbance may be a novel pathological mechanism leading to DA neuronal injury under conditions of proteasome inhibition.

Glial cell-derived neurotrophic factor protects against proteasome inhibition-induced dopamine neuron degeneration by suppression of endoplasmic reticulum stress and caspase-3 activation.

Evidence has shown that ubiquitin proteasome system (UPS) impairment plays an important role in the dopamine (DA) neurodegeneration in Parkinson's disease (PD). It has been reported that application of proteasomal inhibitor lactacystin in ventral mesencephalon (VM) cultures can cause DA neurodegeneration, although the underlying mechanisms are not clear. Herein, we used the lactacystin-induced DA cell degeneration model to study the neuroprotection of glial cell-derived neurotrophic factor (GDNF) in VM cultures. We measured the expression of endoplasmic reticulum stress (ERS)-related genes, and determined the caspase-3 activation, apoptotic cell death, as well as alpha-synuclein-positive inclusions in DA neurons. We found that GDNF treatment significantly suppressed the expression of ERS-related genes and inhibited the activation of caspase-3 and apoptotic cell death without affecting alpha-synuclein-positive inclusions in DA neurons. Our study suggests that the protection of GDNF against DA neurodegeneration in the UPS impairment model is associated with ERS and caspase-3 suppression.

miR-183 cluster scales mechanical pain sensitivity by regulating basal and neuropathic pain genes.

Nociception is protective and prevents tissue damage but can also facilitate chronic pain. Whether a general principle governs these two types of pain is unknown. Here, we show that both basal mechanical and neuropathic pain are controlled by the microRNA-183 (miR-183) cluster in mice. This single cluster controls more than 80% of neuropathic pain-regulated genes and scales basal mechanical sensitivity and mechanical allodynia by regulating auxiliary voltage-gated calcium channel subunits α2δ-1 and α2δ-2. Basal sensitivity is controlled in nociceptors, and allodynia involves TrkB+ light-touch mechanoreceptors. These light-touch-sensitive neurons, which normally do not elicit pain, produce pain during neuropathy that is reversed by gabapentin. Thus, a single microRNA cluster continuously scales acute noxious mechanical sensitivity in nociceptive neurons and suppresses neuropathic pain transduction in a specific, light-touch-sensitive neuronal type recruited during mechanical allodynia.