BackgroundLong non-protein-coding RNAs (lncRNAs) are involved in the pathological processes of nervous system diseases. NONRATT021972 is an lncRNA. This study explores the effects of lncRNA NONRATT021972 small interference RNA (siRNA) on diabetic neuropathic pain (DNP) mediated by the P2X7 receptor in the rat dorsal root ganglia (DRG).ResultsOur results show that NONRATT021972 expression was significantly higher in the DRG of diabetes mellitus (DM) group compared with control group. NONRATT021972 expression in the DRG was reduced when DM rats were treated with NONRATT021972 siRNA. NONRATT021972 siRNA treatment in type 2 DM rats increased the mechanical withdrawal threshold (MWT), the thermal withdrawal latency (TWL) and the sensory nerve conduction velocity (SNCV) of rat tail nerves. After intravenous injection with NONRATT021972 siRNA in DM rats, the P2X7, GFAP and TNF-ɑ expression levels in DRG were decreased. An interaction between the RNA (NONRATT021972) and protein (P2X7) was predicted by the application of bioinformatics technology. The BzATP-activated currents in DRG non-neurons (satellite glial cells) of DM rats were significantly increased compared to control rats. NONRATT021972 siRNA treatment inhibited the ATP-activated currents in HEK293 cells transfected with pEGFP-P2X7.ConclusionsNONRATT021972 siRNA treatment can decrease the expression levels of P2X7 mRNA and protein and inhibit the activation of satellite glial cells (SGCs) in the DRG of type 2 DM rats. Moreover, NONRATT021972 siRNA treatment reduced the release of inflammatory factors (TNF-α), thereby inhibiting the excitability of DRG neurons and reducing mechanical and thermal hyperalgesia in type 2 DM rats.

Some long non-coding RNAs (lncRNAs) participate in physiological processes that maintain cellular and tissue homeostasis, and thus, the dysregulated expression of lncRNAs is involved in the onset and progression of many pathological conditions. Research has indicated that the genetic knockout of some lncRNAs in mice resulted in peri-or postnatal lethality or developmental defects. Diabetes mellitus (DM) is a major cause of peripheral neuropathy. Our studies showed that the expression levels of lncRNA uc.48+ in the diabetic rat dorsal root ganglia (DRG) and the DM patients' serum samples were increased. It suggested that lncRNA uc.48+ was involved in the pathophysiological process of DM. The aim of this study was to investigate the effects of lncRNA uc.48+ small interfering RNA (siRNA) on diabetic neuropathic pain (DNP) mediated by the P2X 3 receptor in the DRG. The values of the mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured by the von Frey test and Hargreaves' test, respectively. The levels of P2X 3 protein and messenger RNA (mRNA) in the DRG were detected by reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, and western blotting. The experiments showed that the MWT and TWL values in DM rats were lower than those in the control rats. The MWT and TWL values in DM rats treated with lncRNA uc.48+ siRNA were increased compared to those in DM rats, but there was no significant difference between the DM rat group and the DM + scramble siRNA group. The levels of P2X 3 protein and mRNA in the DM DRG were higher than those in the control, while the levels of P2X 3 protein and mRNA in the DG of DM rats treated with uc.48+ siRNA were significantly decreased compared to those in DM rats. The expression levels of TNF-α in the DRG of DM rats treated with uc.48+ siRNA were significantly decreased compared to those in the DM group. The phosphorylation and activation of ERK1/2 in the DM DRG were decreased by uc.48+ siRNA treatment. Therefore, uc.48+ siRNA treatment may alleviate the DNP by inhibiting the excitatory transmission mediated by the P2X 3 receptor in DRG.

Retinal ganglion cell axons exit the eye, enter the optic stalk, cross the ventral midline at the optic chiasm, and terminate in the optic tectum of the zebrafish. While in the optic stalk, they grow immediately adjacent to cells expressing the powerful retinal axon repellent slit2. The chemokine stromal cell-derived factor-1 (SDF1) is expressed within the optic stalk and its receptor CXCR4 is expressed in retinal ganglion cells. SDF1 makes cultured retinal axons less responsive to slit2. Here, we show that reducing SDF1 signaling in vivo rescues retinal axon pathfinding errors in zebrafish mutants that have a partial functional loss of the slit receptor robo2. In contrast, reducing SDF1 signaling in animals that completely lack the robo2 receptor does not rescue retinal guidance errors. These results demonstrate that endogenous levels of SDF1 antagonize the repellent effects of slit/robo signaling in vivo and that this antagonism is important during axonal pathfinding.

Vertebrate cranial ectodermal placodes are transient, paired thickenings of embryonic head ectoderm that are crucial for the formation of the peripheral sensory nervous system: they give rise to the paired peripheral sense organs (olfactory organs, inner ears and anamniote lateral line system), as well as the eye lenses, and most cranial sensory neurons. Here, we present the first detailed spatiotemporal fate-maps in any vertebrate for the ophthalmic trigeminal (opV) and maxillomandibular trigeminal (mmV) placodes, which give rise to cutaneous sensory neurons in the ophthalmic and maxillomandibular lobes of the trigeminal ganglion. We used focal DiI and DiO labelling to produce eight detailed fate-maps of chick embryonic head ectoderm over approximately 24 h of development, from 0-16 somites. OpV and mmV placode precursors arise from a partially overlapping territory; indeed, some individual dyespots labelled both opV and mmV placode-derived cells. OpV and mmV placode precursors are initially scattered within a relatively large region of ectoderm adjacent to the neural folds, intermingled both with each other and with future epidermal cells, and with geniculate and otic placode precursors. Although the degree of segregation increases with time, there is no clear border between the opV and mmV placodes even at the 16-somite stage, long after neurogenesis has begun in the opV placode, and when neurogenesis is just beginning in the mmV placode. Finally, we find that occasional cells in the border region between the opV placode and mmV placode express both Pax3 (an opV placode specific marker) and Neurogenin1 (an mmV placode specific marker), suggesting that a few cells are responding to both opV and mmV placode-inducing signals. Overall, our results fill a large gap in our knowledge of the early stages of development of both the opV and mmV placodes, providing an essential framework for subsequent studies of the molecular control of their development.

Long noncoding RNAs (lncRNAs) participate in physiological and pathophysiological processes. Type 2 diabetes mellitus (T2DM) accounts for more than 90 % of all cases of diabetes mellitus (DM). Diabetic neuropathic pain (DNP) is a common complication of T2DM. The aim of this study was to investigate the effects of lncRNA NONRATT021972 small interference RNA (siRNA) on DNP mediated by the P2X receptor in dorsal root ganglia (DRG). These experiments showed that the expression levels of NONRATT021972 in DRG were increased in the T2DM rat model (intraperitoneal injection of STZ with 30 mg/kg). The concentration of NONRATT021972 in T2DM patient serum was higher compared to control healthy subjects. The mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) in T2DM rats were lower compared to control rats. MWT and TWL in T2DM rats treated with NONRATT021972 siRNA were higher compared with those in T2DM rats. The expression levels of the P2X protein and messenger RNA (mRNA) of T2DM rat DRG were higher compared to the control, while those in T2DM rats treated with NONRATT021972 siRNA were significantly lower compared to T2DM rats. The level of tumor necrosis factor-α (TNF-α) in the serum of T2DM rats treated with NONRATT021972 siRNA was significantly decreased compared with T2DM rats. NONRATT021972 siRNA inhibited the phosphorylation and activation of ERK1/2 in T2DM DRG. Thus, NONRATT021972 siRNA treatment may suppress the upregulated expression and activation of the P2X receptor and reduce the hyperalgesia potentiated by the pro-inflammatory cytokine TNF-α in T2DM rats.