Brain-enriched guanylate kinase-associated protein, a component of the post-synaptic density protein complexes, contributes to learning and memory.

Brain-enriched guanylate kinase-associated protein (BEGAIN) is highly enriched in the post-synaptic density (PSD) fraction and was identified in our previous study as a protein associated with neuropathic pain in the spinal dorsal horn. PSD protein complexes containing N-methyl-D-aspartate receptors are known to be involved in neuropathic pain. Since these PSD proteins also participate in learning and memory, BEGAIN is also expected to play a crucial role in this behavior.

Combination therapy with lenvatinib and radiation significantly inhibits thyroid cancer growth by uptake of tyrosine kinase inhibitor.

Although surgical treatment cures >90% of differentiated thyroid cancer (DTC) patients, the remaining patients, including advanced DTC cases, have poor clinical outcomes. These patients with inoperable disease have only two choices of radioactive iodine therapy and tyrosine kinase inhibitors such as lenvatinib, which have a high incidence of treatment-related adverse events and can only prolong progression free survival by approximately 5-15 months. In this study, we investigated the antitumor effects of combination therapy with lenvatinib and radiation (CTLR) for DTC.

Diabetic neuropathy research: from mouse models to targets for treatment.

Diabetic neuropathy is one of the most serious complications of diabetes, and its increase shows no sign of stopping. Furthermore, current clinical treatments do not yet approach the best effectiveness. Thus, the development of better strategies for treating diabetic neuropathy is an urgent matter.

Distribution of Caskin1 protein and phenotypic characterization of its knockout mice using a comprehensive behavioral test battery.

Calcium/calmodulin-dependent serine protein kinase (CASK)-interacting protein 1 (Caskin1) is a direct binding partner of the synaptic adaptor protein CASK. Because Caskin1 forms homo-multimers and binds not only CASK but also other neuronal proteins in vitro, it is anticipated to have neural functions; but its exact role in mammals remains unclear. Previously, we showed that the concentration of Caskin1 in the spinal dorsal horn increases under chronic pain.

Two isoforms of cyclic GMP-dependent kinase-I exhibit distinct expression patterns in the adult mouse dorsal root ganglion.

cGMP-dependent kinase-I (cGKI) is known to regulate spinal pain processing. This enzyme consists of two isoforms (cGKIα and cGKIβ) that show distinct substrate specificity and tissue distribution. It has long been believed that the α isoform is exclusively expressed in the adult dorsal root ganglion.

Impaired peripheral nerve regeneration in type-2 diabetic mouse model.

Peripheral neuropathy is one of the most common and serious complications of type-2 diabetes. Diabetic neuropathy is characterized by a distal symmetrical sensorimotor polyneuropathy, and its incidence increases in patients 40 years of age or older. In spite of extensive research over decades, there are few effective treatments for diabetic neuropathy besides glucose control and improved lifestyle.

Na /K -ATPase coupled to endothelin receptor type B stimulates peripheral nerve regeneration via lactate signalling.

We have recently demonstrated that endothelin (ET) is functionally coupled to Na , a Na concentration-sensitive Na channel for lactate release via ET receptor type B (ET R) and is involved in peripheral nerve regeneration in a sciatic nerve transection-regeneration mouse model. Na is known to interact directly with Na /K -ATPase, leading to lactate production in the brain. To investigate the role of Na /K -ATPase in peripheral nerve regeneration, in this study, we applied ouabain, a Na /K -ATPase inhibitor, to the cut site for 4 weeks with an osmotic pump.

Involvement of Brain-Enriched Guanylate Kinase-Associated Protein (BEGAIN) in Chronic Pain after Peripheral Nerve Injury.

Maintenance of neuropathic pain caused by peripheral nerve injury crucially depends on the phosphorylation of GluN2B, a subunit of the N-methyl-d-aspartate (NMDA) receptor, at Tyr1472 (Y1472) and subsequent formation of a postsynaptic density (PSD) complex of superficial spinal dorsal horn neurons. Here we took advantage of comparative proteomic analysis based on isobaric stable isotope tags (iTRAQ) between wild-type and knock-in mice with a mutation of Y1472 to Phe of GluN2B (Y1472F-KI) to search for PSD proteins in the spinal dorsal horn that mediate the signaling downstream of phosphorylated Y1472 GluN2B. Among several candidate proteins, we focused on brain-enriched guanylate kinase-associated protein (BEGAIN), which was specifically up-regulated in wild-type mice after spared nerve injury (SNI).

Role of c-Jun N-terminal kinase in late nerve regeneration monitored by in vivo imaging of thy1-yellow fluorescent protein transgenic mice.

The restoration of function to injured peripheral nerves separated by a gap requires regeneration across it and reinnervation to target organs. To elucidate these processes, we have established an in vivo monitoring system of nerve regeneration in thy1-yellow fluorescent protein transgenic mice expressing a fluorescent protein in their nervous system. Here we demonstrated that motor and sensory nerves were regenerated in a coordinated fashion across the gap and that the functional recovery of the response to mechanical stimuli correlated well with sensory innervation to the foot.

Involvement of Nax sodium channel in peripheral nerve regeneration via lactate signaling.

Na(x), a sodium concentration-sensitive sodium channel, is expressed in non-myelinating Schwann cells of the adult peripheral nervous system, but the pathophysiological role remains unclear. We found that functional recovery of the hind paw responses from the sciatic nerve transection was delayed in Na(x) knockout (Na(x)⁻/⁻) mice. Histological analyses showed a decrease in the number of regenerated myelinated axons in (Na(x)⁻/⁻) sciatic nerves.

Identification of nitrated tyrosine residues of protein kinase G-Iα by mass spectrometry.

The nitration of tyrosine to 3-nitrotyrosine is an oxidative modification of tyrosine by nitric oxide and is associated with many diseases, and targeting of protein kinase G (PKG)-I represents a potential therapeutic strategy for pulmonary hypertension and chronic pain. The direct assignment of tyrosine residues of PKG-I has remained to be made due to the low sensitivity of the current proteomic approach. In order to assign modified tyrosine residues of PKG-I, we nitrated purified PKG-Iα expressed in insect Sf9 cells by use of peroxynitrite in vitro and analyzed the trypsin-digested fragments by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and liquid chromatography-tandem mass spectrometry.

Proteomic analysis of cerebrospinal fluid before and after intrathecal injection of steroid into patients with postherpetic pain.

Postherpetic neuralgia (PHN) is the most frequent complication of herpes zoster, and the risk of it increases with age. By comparing proteomes of the cerebrospinal fluid (CSF) before and after the treatment, it may be possible to identify proteins that play a role in PHN and to predict responses to various treatments. To address this issue, we enrolled eight outpatients with PHN over 55 years of age and treated them with intrathecal methylprednisolone and lidocaine four times every week, collecting CSF samples before the treatment at each visit.

Involvement of Tyr1472 phosphorylation of NMDA receptor NR2B subunit in postherpetic neuralgia in model mice.

Background: Postherpetic neuralgia is spontaneous pain and allodynia that persist long after the disappearance of the cutaneous lesions caused by herpes zoster. Inoculation of mice with herpes simplex virus-1 causes herpes zoster-like skin lesions and herpetic and postherpetic pain. Although NMDA receptors have been suggested to be involved in postherpetic pain as in other types of neuropathic pain, the neural mechanism remains unclear.

Rapid S-nitrosylation of actin by NO-generating donors and in inflammatory pain model mice.

Background: S-Nitrosylation, the reversible post-translational modification of reactive cysteine residues in proteins, has emerged as an important mechanism by which NO acts as a signaling molecule. We recently demonstrated that actin is a major S-nitrosylated protein in the spinal cord and suggested that NO directly attenuates dopamine release from PC12 cells by causing the breakdown of F-actin. However, the occurrence of S-nitrosylation of actin remained unclarified in animal pain model.

Restricted expression of Ovol2/MOVO in XY body of mouse spermatocytes at the pachytene stage.

The development of multicellular organisms is controlled by sequential activation of a hierarchy of regulatory genes, which encode transcription factors having DNA-binding motifs. We previously identified a testis-specific zinc finger transcriptional factor, Ovol2/MOVO, as a mouse homologue of Drosophila Ovo. Because mice deficient in Ovol2/Movo die during early embryogenesis, its function in male germ cells has remained unknown.

Reversal of inducible nitric oxide synthase uncoupling unmasks tolerance to ischemia/reperfusion injury in the diabetic rat heart.

The diabetic heart is known to be susceptible to ischemia/reperfusion (I/R) injury by increased oxidative stress. Although oxidative stress upregulates inducible nitric oxide (iNOS), the role of iNOS in I/R injury in the diabetic heart has been poorly understood. Because iNOS-derived nitric oxide (NO) plays a crucial role in cardioprotection against I/R injury, we hypothesized that inhibition of iNOS uncoupling would restore tolerance to I/R injury in the diabetic heart.

Involvement of spinal phosphorylation cascade of Tyr1472-NR2B, Thr286-CaMKII, and Ser831-GluR1 in neuropathic pain.

Previously we demonstrated that phosphorylation of NR2B subunits of the N-methyl-D-aspartate (NMDA) glutamate receptor at Tyr1472 is increased in a neuropathic-pain model and that this phosphorylation is required for the maintenance of neuropathic pain by L5-spinal nerve transection. We obtained these results by using a selective NR2B antagonist and mice deficient in Fyn, which is an Src-family tyrosine protein kinase. However, how Tyr1472 phosphorylation of NR2B is involved in the maintenance of neuropathic pain was unclear.

A novel role of prostaglandin E2 in neuropathic pain: blockade of microglial migration in the spinal cord.

Neuropathic pain produced by damage to or dysfunction of the nervous system is a common and severely disabling state that affects millions of people worldwide. Recent evidence indicates that activated microglia are key cellular intermediaries in the pathogenesis of neuropathic pain and that ATP serves as the mediator. However, the in vivo mechanism underlying the retention of activated microglia in the injured region has not yet been completely elucidated.

Impairment of CaMKII activation and attenuation of neuropathic pain in mice lacking NR2B phosphorylated at Tyr1472.

Ca(2+) /calmodulin-dependent protein kinase II (CaMKII) is a key mediator of long-term potentiation (LTP), which can be triggered by N-methyl-d-aspartate (NMDA) receptor-mediated Ca(2+) influx. We previously demonstrated that Fyn kinase-mediated phosphorylation of NR2B subunits of NMDA receptors at Tyr1472 in the dorsal horn was involved in a neuropathic pain state even 1 week after nerve injury. Here we show that Y1472F-KI mice with a knock-in mutation of the Tyr1472 site to phenylalanine did not exhibit neuropathic pain induced by L5 spinal nerve transection, whereas they did retain normal nociceptive responses and induction of inflammatory pain.

Involvement of S-nitrosylation of actin in inhibition of neurotransmitter release by nitric oxide.

Background: The role of the diffusible messenger nitric oxide (NO) in the regulation of pain transmission is still a debate of matter, pro-nociceptive and/or anti-nociceptive. S-Nitrosylation, the reversible post-translational modification of selective cysteine residues in proteins, has emerged as an important mechanism by which NO acts as a signaling molecule. The occurrence of S-nitrosylation in the spinal cord and its targets that may modulate pain transmission remain unclarified.

N-ethylmaleimide-sensitive fusion protein (NSF) is involved in central sensitization in the spinal cord through GluR2 subunit composition switch after inflammation.

Central sensitization, similar to long-term potentiation in the hippocampus, refers to the increased synaptic efficacy established in somatosensory neurons in the dorsal horn of the spinal cord following tissue injury or nerve damage. In the course of inflammation, many proteins including glutamate receptors are assumed to be dynamically reorganized in the postsynaptic density (PSD) and involved in persistent pain. Mechanical hyperalgesia induced by intraplantar injection of complete Freund's adjuvant (CFA) was inhibited at 4 h, but not at 24 h, by indomethacin, an inhibitor of prostanoid synthesis.

Characterization of signaling pathway for the translocation of neuronal nitric oxide synthase to the plasma membrane by PACAP.

In the central nervous system, the activation of neuronal nitric oxide synthase (nNOS) is closely associated with activation of NMDA receptor, and trafficking of nNOS may be a prerequisite for efficient NO production at synapses. We recently demonstrated that pituitary adenylate cyclase activating polypeptide (PACAP) and NMDA synergistically caused the translocation of nNOS to the membrane and stimulated NO production in PC12 (pheochromocytoma) cells. However, the mechanisms responsible for trafficking and activation of nNOS are largely unknown.

Nitric oxide (NO) serves as a retrograde messenger to activate neuronal NO synthase in the spinal cord via NMDA receptors.

We have recently demonstrated that nitric oxide (NO) produced by neuronal NO synthase (nNOS) in the spinal cord is involved in the maintenance of neuropathic pain. To clarify whether NO itself affected nNOS activity in the spinal cord as a retrograde messenger, we examined the involvement of the NO/cGMP signaling pathway in the regulation of nNOS activity by NADPH-diaphorase histochemistry. NO-generating agents NOR3 (t(1/2)=30min) and SNAP (t(1/2)=5h), but not NOR1 (t(1/2)=1.