Recent advances in the treatment of oral ulcerative mucositis from clinical and basic perspectives.

BACKGROUND: Oral ulcerative mucositis (OUM) is common in patients with cancer, particularly in those undergoing chemoradiation therapy. The effective management of OUM is crucial for continuous cancer care and patient well-being. Recent studies have advanced our understanding of the causes, leading to clinical trials toward novel treatments. This review focuses on the contemporary therapeutic landscape, and provides the latest insights into the mechanisms of mucosal healing and pain. HIGHLIGHTS: Management strategies for oral ulcerative mucositis in patients with cancer include maintaining good oral hygiene, reducing mucosal irritation against radiation, and using various topical analgesic treatments, including herbal medicines. However, the current management practices have limitations that necessitate the development of more efficacious and novel treatments. Molecular research on transient receptor potential (TRP) channels in the oral mucosa is crucial for understanding the mechanisms of wound healing and pain in patients with OUM. Targeting TRP subfamily V member 3 (V3) and TRPV4 can enhance wound healing through re-epithelialization. The suppression of TRPV1, TRPA1, and TRPV4 may be effective in alleviating OUM-induced pain. CONCLUSION: Research advancements have improved our understanding and potentially led to novel treatments that offer symptomatic relief. This progress highlights the importance of collaborations between clinical researchers and scientists in the development of innovative therapies.

Involvement of skin TRPV3 in temperature detection regulated by TMEM79 in mice.

TRPV3, a non-selective cation transient receptor potential (TRP) ion channel, is activated by warm temperatures. It is predominantly expressed in skin keratinocytes, and participates in various somatic processes. Previous studies have reported that thermosensation in mice lacking TRPV3 was impaired. Here, we identified a transmembrane protein, TMEM79, that acts as a negative regulator of TRPV3. Heterologous expression of TMEM79 was capable of suppressing TRPV3-mediated currents in HEK293T cells. In addition, TMEM79 modulated TRPV3 translocalization and promoted its degradation in the lysosomes. TRPV3-mediated currents and Ca2+ influx were potentiated in primary mouse keratinocytes lacking TMEM79. Furthermore, TMEM79-deficient male mice preferred a higher temperature than did wild-type mice due to elevated TRPV3 function. Our study revealed unique interactions between TRPV3 and TMEM79, both in vitro and in vivo. These findings support roles for TMEM79 and TRPV3 in thermosensation.

Correlation Between Work Motivation and Life Events in Female Physicians.

This study interviewed 39 mother-doctors from two university hospitals in Japan to investigate how certain stages in their lives influenced their working motivation. We conceptualized a Motivational Drive Chart to track changes of work motivation from enrollment in medical courses to the present day, recording changes in motivational values, age, and life events. It was found that the average value of motivation increased from the beginning of medical school enrollment until graduation; however, a sudden drop was noted in the age group 25 to 29 due to childcare and work-life conflicts. Motivational values were found to gradually increase in the 30 to 34 age group, owing to professional accomplishments, such as obtaining a specialist license. In Japanese society, social roles have traditionally been divided between men and women. The present study found that Japanese female doctors faced a decrease in work motivation during childrearing stages. The finding suggests that new avenues should be explored to support mother-doctors.

Transient Receptor Potential Channel Vanilloid 1 Contributes to Facial Mechanical Hypersensitivity in a Mouse Model of Atopic Asthma.

Sensitive skin, a common pathophysiological feature of allergic diseases, is defined as an unpleasant sensation in response to stimuli that normally should not provoke such sensations. However, the relationship between allergic inflammation and hypersensitive skin in the trigeminal system remains to be elucidated. To explore whether bronchial allergic inflammation affects facial skin and primary sensory neurons, we used an ovalbumin (OVA)-induced asthma mouse model. Significant mechanical hypersensitivity was observed in the facial skin of mice with pulmonary inflammation induced by OVA sensitization compared to mice treated with adjuvant or vehicle as controls. The skin of OVA-treated mice showed an increased number of nerve fibers, especially rich intraepithelial nerves, compared to controls. Transient receptor potential channel vanilloid 1 (TRPV1)-immunoreactive nerves were enriched in the skin of OVA-treated mice. Moreover, epithelial TRPV1 expression was higher in OVA-treated mice than in controls. Trigeminal ganglia of OVA-treated mice displayed larger numbers of activated microglia/macrophages and satellite glia. In addition, more TRPV1 immunoreactive neurons were found in the trigeminal ganglia of OVA-treated mice than in controls. Mechanical hypersensitivity was suppressed in OVA-treated Trpv1-deficient mice, while topical skin application of a TRPV1 antagonist before behavioral testing reduced the reaction induced by mechanical stimulation. Our findings reveal that mice with allergic inflammation of the bronchi had mechanical hypersensitivity in the facial skin that may have resulted from TRPV1-mediated neuronal plasticity and glial activation in the trigeminal ganglion.

Increased GLUT1 expression and localization to Golgi apparatus of acinar cells in the parotid gland of Goto-Kakizaki diabetic rats.

OBJECTIVE: Patients with diabetes are known to have high salivary glucose levels. But the mechanisms are still unclear. We hypothesized that the topological changes of glucose transporters affect the salivary glucose level. METHODS: We used adult Goto-Kakizaki (GK) rats, an animal model of advanced diabetes, and Wistar rats as a control, with or without glucose load. The sections of salivary glands from the animals were processed for standard histological, immunohistochemical, and immunofluorescent staining. RESULTS: Parotid acinar cells of GK rats appeared like mucous filled with low-eosin-stained granules and possessing a flat nucleus located basally, whereas those of Wistar rats appeared as a typical serous gland with eosin-rich cytoplasm and a spherical nucleus. Cytoplasmic granules of GK rat parotid acinar cells showed no reaction of polysaccharide staining. In acinar cell cytoplasm of GK rats, intense GLUT1 immunoreactivity was observed compared to Wistar rats. By double immunostaining for GLUT1 and Golgi apparatus-specific markers, it was determined that GLUT1 was localized to the Golgi apparatus. By glucose loading in starved GK rats, the distribution of GLUT1-immunoreactive signals was spread out clearly from the apical side of the nucleus to the basolateral side. CONCLUSIONS: In rat model of diabetes, highly localized GLUT1 at Golgi apparatus in acinar cells seems to increase taking up cytoplasmic glucose to form exocytotic vesicles. This phenomenon may transform parotid glands from serous to mucous-like and result in saccharide-rich saliva.

Immunohistochemical characterization of transient receptor potential vanilloid types 2 and 1 in a trinitrobenzene sulfonic acid-induced rat colitis model with visceral hypersensitivity.

Transient receptor potential vanilloid type 2 (TRPV2) and type 1 (TRPV1) are originally identified as heat-sensitive TRP channels. We compared the expression patterns of TRPV2 and TRPV1 in the rat distal colon and extrinsic primary afferent neurons, and investigated their roles in visceral hypersensitivity in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis rats. Both TRPV2 and TRPV1 expressions in the colon, dorsal root ganglion (DRG), and nodose ganglion (NG) were significantly upregulated in the TNBS-induced colitis model. TRPV2 cell bodies co-localized with the intrinsic primary afferent marker NeuN and the inhibitory motor neuronal marker nNOS in the myenteric plexus. TRPV2 expressions were further detected in the resident macrophage marker ED2 in the mucosa. In contrast, no TRPV1-expressing cell bodies were detected in the myenteric plexus. Both TRPV2- and TRPV1-positive cell bodies in the DRG and NG were double-labeled with the neuronal retrograde tracer fluorescent fluorogold. Large- and medium-sized TRPV2-positive neurons were labeled with the A-fiber marker NF200, calcitonin gene-related peptide (CGRP), and substance P (SP) in the DRG while small-sized TRPV1-positive neurons were labeled with the C-fiber markers IB4, CGRP, and SP. TRPV2- and TRPV1-positive NG neurons were labeled with NF200 and IB4. TNBS treatment increased p-ERK1/2-positive cells in TRPV2 and TRPV1 neurons but did not affect the TRPV2 and TRPV1 subpopulations in the DRG and NG. Both TRPV2 and TRPV1 antagonists significantly alleviated visceral hypersensitivity in TNBS-induced colitis model rats. These findings suggest that intrinsic/extrinsic TRPV2- and extrinsic TRPV1-neurons contribute to visceral hypersensitivity in an experimental colitis model.

Expression and localisation of Rab44 in immune-related cells change during cell differentiation and stimulation.

Rab44 is a large Rab GTPase that contains a Rab-GTPase domain and some additional domains, such as EF-hand and coiled-coil domains at the N-terminus. Our previous study showed that Rab44 negatively regulates osteoclast differentiation by modulating intracellular calcium levels; however, aside from those findings, there is little information concerning Rab44 on other cells or tissues. In this study, we showed that Rab44 was highly expressed in bone marrow cells among various mouse tissues. Immunohistochemical studies indicated that Rab44 was detectable by only a small number of cells in the immune-related tissues and that Rab44 was partially detected in CD117-positive cells, but not in Stem cell antigen 1-positive cells in the bone marrow. Rab44 expression levels were decreased during differentiation of immune-related cells, such as neutrophils, macrophages, and dendritic cells compared with bone marrow cells. Although endogenous Rab44 in macrophages was localised in lysosomes, lipopolysaccharide (LPS) stimulation led to partial translocation to early endosomes and the plasma membrane. Moreover, Rab44 expression levels were altered by treatment with various immunomodulators, including LPS. These results indicate that Rab44 expression and localisation in bone marrow cells and macrophages alters with cell differentiation and stimulation.

Reduced Post-ischemic Brain Injury in Transient Receptor Potential Vanilloid 4 Knockout Mice.

BACKGROUND AND PURPOSE: In the acute phase of ischemia-reperfusion, hypoperfusion associated with ischemia and reperfusion in microvascular regions and disruption of the blood-brain barrier (BBB) contribute to post-ischemic brain injury. We aimed to clarify whether brain injury following transient middle cerebral artery occlusion (tMCAO) is ameliorated in Transient receptor potential vanilloid 4 knockout (Trpv4-/- ) mice. METHODS: tMCAO was induced in wild-type (WT) and Trpv4-/- mice aged 8-10 weeks. Ischemia-induced lesion volume was evaluated by 2,3,5-triphenyltetrazolium chloride staining at 24 h post-tMCAO. Tissue water content and Evans blue leakage in the ipsilateral hemisphere and a neurological score were evaluated at 48 h post-tMCAO. Transmission electron microscopy (TEM) was performed to assess the morphological changes in microvasculature in the ischemic lesions at 6 h post-tMCAO. RESULTS: Compared with WT mice, Trpv4-/- mice showed reduced ischemia-induced lesion volume and reduced water content and Evans blue leakage in the ipsilateral hemisphere alongside milder neurological symptoms. The loss of zonula occludens-1 and occludin proteins in the ipsilateral hemisphere was attenuated in Trpv4-/- mice. TEM revealed that parenchymal microvessels in the ischemic lesion were compressed and narrowed by the swollen endfeet of astrocytes in WT mice, but these effects were markedly ameliorated in Trpv4-/- mice. CONCLUSION: The present results demonstrate that TRPV4 contributes to post-ischemic brain injury. The preserved microcirculation and BBB function shortly after reperfusion are the key neuroprotective roles of TRPV4 inhibition, which represents a promising target for the treatment of acute ischemic stroke.

Enhanced junctional epithelial permeability in TRPV4-deficient mice.

BACKGROUND AND OBJECTIVE: As the interface between the oral cavity and the teeth, the junctional epithelial barrier is critical for gingival defense. The junctional epithelium is subject to mechanical stresses from biting force or external insults such as bacterial attacks, but little is known about the effects of mechanical stimuli on epithelial functions. Transient receptor potential vanilloid 4 (TRPV4) functions as a mechanosensitive nonselective cation channel. In the present study, based on marked expression of TRPV4 in the mouse junctional epithelium, we aimed to clarify the putative links between TRPV4 and junctional complexes in the junctional epithelium. METHODS AND RESULTS: Histological observations revealed that the junctional epithelium in TRPV4-deficient (TRPV4-/- ) mice had wider intercellular spaces than that in wild-type (TRPV4+/+ ) mice. Exogenous tracer penetration in the junctional epithelium was greater in TRPV4-/- mice than in TRPV4+/+ mice, and immunoreactivity for adherens junction proteins was suppressed in TRPV4-/- mice compared with TRPV4+/+ mice. Analysis of a mouse periodontitis model showed greater bone volume loss in TRPV4-/- mice compared with TRPV4+/+ mice, indicating that an epithelial barrier deficiency in TRPV4-/- mice may be associated with periodontal complications. CONCLUSION: The present findings identify a crucial role for TRPV4 in the formation of adherens junctions in the junctional epithelium, which could regulate its permeability. TRPV4 may be a candidate pharmacological target to combat periodontal diseases.

The TRPV4-AKT axis promotes oral squamous cell carcinoma cell proliferation via CaMKII activation.

Most human malignant tumor cells arise from epithelial tissues, which show distinctive characteristics, such as polarization, cell-to-cell contact between neighboring cells, and anchoring to a basement membrane. When tumor cells invaginate into the stroma, the cells are exposed to extracellular environments, including the extracellular matrix (ECM). Increased ECM stiffness has been reported to promote cellular biological activities, such as excessive cellular growth and enhanced migration capability. Therefore, tumorous ECM stiffness is not only an important clinical tumor feature but also plays a pivotal role in tumor cell behavior. Transient receptor potential vanilloid 4 (TRPV4), a Ca2+-permeable nonselective cation channel, has been reported to be mechano-sensitive and to regulate tumorigenesis, but the underlying molecular mechanism in tumorigenesis remains unclear. The function of TRPV4 in oral squamous cell carcinoma (OSCC) is also unknown. The current study was conducted to investigate whether or not TRPV4 might be involved in OSCC tumorigenesis. TRPV4 mRNA levels were elevated in OSCC cell lines compared with normal oral epithelial cells, and its expression was required for TRPV4 agonist-dependent Ca2+ entry. TRPV4-depleted tumor cells exhibited decreased proliferation capabilities in three-dimensional culture but not in a low-attachment plastic dish. A xenograft tumor model demonstrated that TRPV4 expression was involved in cancer cell proliferation in vivo. Furthermore, loss-of-function experiments using siRNA or an inhibitor revealed that the TRPV4 expression was required for CaMKII-mediated AKT activation. Immunohistochemical analyses of tissue specimens obtained from 36 OSCC patients showed that TRPV4 was weakly observed in non-tumor regions but was strongly expressed in tumor lesions at high frequencies where phosphorylated AKT expression was frequently detected. These results suggest that the TRPV4/CaMKII/AKT axis, which might be activated by extracellular environments, promotes OSCC tumor cell growth.

CALHM1/CALHM3 channel is intrinsically sorted to the basolateral membrane of epithelial cells including taste cells.

The CALHM1/CALHM3 channel in the basolateral membrane of polarized taste cells mediates neurotransmitter release. However, mechanisms regulating its localization remain unexplored. Here, we identified CALHM1/CALHM3 in the basolateral membrane of type II taste cells in discrete puncta localized close to afferent nerve fibers. As in taste cells, CALHM1/CALHM3 was present in the basolateral membrane of model epithelia, although it was distributed throughout the membrane and did not show accumulation in puncta. We identified canonical basolateral sorting signals in CALHM1 and CALHM3: tyrosine-based and dileucine motifs. However, basolateral sorting remained intact in mutated channels lacking those signals, suggesting that non-canonical signals reside elsewhere. Our study demonstrates intrinsic basolateral sorting of CALHM channels in polarized cells, and provides mechanistic insights.

Impaired Junctions and Invaded Macrophages in Oral Epithelia With Oral Pain.

Recurrent or chronic oral pain is a great burden for patients. Recently, the links between epithelial barrier loss and disease were extended to include initiation and propagation. To explore the effects of pathohistological changes in oral epithelia on pain, we utilized labial mucosa samples in diagnostic labial gland biopsies from patients with suspected Sjögren's syndrome (SS), because they frequently experience pain and discomfort. In most labial mucosa samples from patients diagnosed with SS, disseminated epithelial cellular edema was prevalent as ballooning degeneration. The disrupted epithelia contained larger numbers of infiltrating macrophages in patients with oral pain than in patients without pain. Immunohistochemistry revealed that edematous areas were distinct from normal areas, with disarranged cell-cell adhesion molecules (filamentous actin, E-cadherin, ß-catenin). Furthermore, edematous areas were devoid of immunostaining for transient receptor potential channel vanilloid 4 (TRPV4), a key molecule in adherens junctions. In an investigation on whether impaired TRPV4 affect cell-cell adhesion, calcium stimulation induced intimate cell-cell contacts among oral epithelial cells from wild-type mice, while intercellular spaces were apparent in cells from TRPV4-knockout mice. The present findings highlight the relationship between macrophages and epithelia in oral pain processing, and identify TRPV4-mediated cell-cell contacts as a possible target for pain treatment.

A Novel Autoantibody against Plexin D1 in Patients with Neuropathic Pain.

OBJECTIVE: To identify novel autoantibodies for neuropathic pain (NeP). METHODS: We screened autoantibodies that selectively bind to mouse unmyelinated C-fiber type dorsal root ganglion (DRG) neurons using tissue-based indirect immunofluorescence assays (IFA) with sera from 110 NeP patients with various inflammatory and allergic neurologic diseases or other neuropathies, and 50 controls without NeP including 20 healthy subjects and 30 patients with neurodegenerative diseases or systemic inflammatory diseases. IgG purified from IFA-positive patients' sera was subjected to Western blotting (WB) and immunoprecipitation (IP) using mouse DRG lysates. Immunoprecipitates were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify target autoantigens. RESULTS: Antiunmyelinated C-fiber type DRG neuron antibodies were more frequent in patients with NeP than non-NeP subjects (10% vs 0%; p < 0.05). These autoantibodies were all from the IgG2 subclass and colocalized mostly with isolectin B4- and P2X3-positive pain-conducting small neurons but not with S100ß-positive myelinated neurons. WB revealed a common immunoreactive band (approximately 220kDa). IP and LC-MS/MS studies identified plexin D1 as a target autoantigen. Immunoadsorption tests with recombinant human plexin D1 in IFA revealed that all 11 anti-small DRG neuron antibody-positive patients had anti-plexin D1 antibodies. Application of anti-plexin D1 antibody-positive patient sera to cultured DRG neurons increased membrane permeability, leading to cellular swelling. NeP patients with anti-plexin D1 antibodies commonly developed burning pain and current perception threshold abnormalities for C-fibers. Main comorbidities were atopy and collagen-vascular disease. Immunotherapies ameliorated NeP in 7 treated cases. INTERPRETATION: Anti-plexin D1 antibodies are a novel biomarker for immunotherapy-responsive NeP. Ann Neurol 2018;84:208-224.

Post-translational palmitoylation controls the voltage gating and lipid raft association of the CALHM1 channel.

KEY POINTS: Calcium homeostasis modulator 1 (CALHM1), a new voltage-gated ATP- and Ca2+ -permeable channel, plays important physiological roles in taste perception and memory formation. Regulatory mechanisms of CALHM1 remain unexplored, although the biophysical disparity between CALHM1 gating in vivo and in vitro suggests that there are undiscovered regulatory mechanisms. Here we report that CALHM1 gating and association with lipid microdomains are post-translationally regulated through the process of protein S-palmitoylation, a reversible attachment of palmitate to cysteine residues. Our data also establish cysteine residues and enzymes responsible for CALHM1 palmitoylation. CALHM1 regulation by palmitoylation provides new mechanistic insights into fine-tuning of CALHM1 gating in vivo and suggests a potential layer of regulation in taste and memory. ABSTRACT: Emerging roles of CALHM1, a recently discovered voltage-gated ion channel, include purinergic neurotransmission of tastes in taste buds and memory formation in the brain, highlighting its physiological importance. However, the regulatory mechanisms of the CALHM1 channel remain entirely unexplored, hindering full understanding of its contribution in vivo. The different gating properties of CALHM1 in vivo and in vitro suggest undiscovered regulatory mechanisms. Here, in searching for post-translational regulatory mechanisms, we discovered the regulation of CALHM1 gating and association with lipid microdomains via protein S-palmitoylation, the only reversible lipid modification of proteins on cysteine residues. CALHM1 is palmitoylated at two intracellular cysteines located in the juxtamembrane regions of the third and fourth transmembrane domains. Enzymes that catalyse CALHM1 palmitoylation were identified by screening 23 members of the DHHC protein acyltransferase family. Epitope tagging of endogenous CALHM1 proteins in mice revealed that CALHM1 is basally palmitoylated in taste buds in vivo. Functionally, palmitoylation downregulates CALHM1 without effects on its synthesis, degradation and cell surface expression. Mutation of the palmitoylation sites has a profound impact on CALHM1 gating, shifting the conductance-voltage relationship to more negative voltages and accelerating the activation kinetics. The same mutation also reduces CALHM1 association with detergent-resistant membranes. Our results comprehensively uncover a post-translational regulation of the voltage-dependent gating of CALHM1 by palmitoylation.

The oral mucosal membrane and transient receptor potential channels.

The oral cavity is the first line of defense, sensation, and secretion of the alimentary canal. Oral perception contributes to the enjoyment of food and beverages and to avoiding consumption of poisonous or harmful substances. Oral sensation is served by somatosensory nervous systems distributed to the oral membrane. Recent studies reported that oral epithelial cells may transduce temperature and touch through membranous sensors, which comprise ion channels with multimodal properties, and nerves. Here, we describe the possible role of oral epithelial cells in oral perception.

Effects of deficiency of Kelch-like ECH-associated protein 1 on skeletal organization: a mechanism for diminished nuclear factor of activated T cells cytoplasmic 1 during osteoclastogenesis.

Kelch-like ECH-associated protein 1 (Keap1) binds to nuclear factor E2 p45-related factor 2 (Nrf2), a transcription factor for antioxidant enzymes, to suppress Nrf2 activation. The role of oxidative stress in many diseases supports the possibility that processes that are associated with Nrf2 activation might offer therapeutic potential. Nrf2 deficiency induces osteoclastogenesis, which is responsible for bone loss, by activating receptor activator of NF-κB ligand (RANKL)-mediated signaling; however, the effects of Keap1 deficiency remain unclear. By using Keap1-deficient newborn mice, we observed that talus and calcaneus bone formation was partially retarded and that osteoclast number was reduced in vivo without severe gross abnormalities. In addition, Keap1-deficient macrophages were unable to differentiate into osteoclasts in vitrovia attenuation of RANKL-mediated signaling and expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1), a key transcription factor that is involved in osteoclastogenesis. Furthermore, Keap1 deficiency up-regulated the expression of Mafb, a negative regulator of NFATc1. RANKL-induced mitochondrial gene expression is required for down-regulation of IFN regulatory factor 8 (IRF-8), a negative transcriptional regulator of NFATc1. Our results indicate that Keap1 deficiency down-regulated peroxisome proliferator-activated receptor-γ coactivator 1ß and mitochondrial gene expression and up-regulated Irf8 expression. These results suggest that the Keap1/Nrf2 axis plays a critical role in NFATc1 expression and osteoclastogenic progression.-Sakai, E., Morita, M., Ohuchi, M., Kido, M. A., Fukuma, Y., Nishishita, K., Okamoto, K., Itoh, K., Yamamoto, M., Tsukuba, T. Effects of deficiency of Kelch-like ECH-associated protein 1 on skeletal organization: a mechanism for diminished nuclear factor of activated T cells cytoplasmic 1 during osteoclastogenesis.

Allergic Inflammation Leads to Neuropathic Pain via Glial Cell Activation.

Allergic and atopic disorders have increased over the past few decades and have been associated with neuropsychiatric conditions, such as autism spectrum disorder and asthmatic amyotrophy. Myelitis presenting with neuropathic pain can occur in patients with atopic disorder; however, the relationship between allergic inflammation and neuropathic pain, and the underlying mechanism, remains to be established. We studied whether allergic inflammation affects the spinal nociceptive system. We found that mice with asthma, atopic dermatitis, or atopic diathesis had widespread and significantly more activated microglia and astroglia in the spinal cord than those without atopy, and displayed tactile allodynia. Microarray analysis of isolated microglia revealed a dysregulated phenotype showing upregulation of M1 macrophage markers and downregulation of M2 markers in atopic mice. Among the cell surface protein genes, endothelin receptor type B (EDNRB) was most upregulated. Immunohistochemical analysis revealed that EDNRB expression was enhanced in microglia and astroglia, whereas endothelin-1, an EDNRB ligand, was increased in serum, lungs, and epidermis of atopic mice. No EDNRA expression was found in the spinal cord. Expression of FBJ murine osteosarcoma viral oncogene homolog B was significantly higher in the dorsal horn neurons of asthma mice than nonatopic mice. The EDNRB antagonist BQ788 abolished glial and neural activation and allodynia. We found increased serum endothelin-1 in atopic patients with myelitis and neuropathic pain, and activation of spinal microglia and astroglia with EDNRB upregulation in an autopsied case. These results suggest that allergic inflammation induces diffuse glial activation, influencing the nociceptive system via the EDNRB pathway. SIGNIFICANCE STATEMENT: The prevalence of allergic disorders has markedly increased over the past few decades. Allergic disorders are associated with neuropsychiatric conditions; however, the relationship between allergic inflammation and CNS complications is unknown. A peculiar myelitis presenting with persistent neuropathic pain has been reported in patients with allergic disorders. We studied how atopy exerts substantial influence on the nociceptive system. We found that mice with allergic disorders had severe allodynia with activated astroglia and microglia, and showed marked upregulation of endothelin-1 (ET-1) receptor type B (EDNRB) in the spinal cord. A selective EDNRB antagonist prevented allodynia and glial activation. Our findings suggest a novel mechanism whereby atopy induces glial activation and neuropathic pain via an ET-1/EDNRB pathway.

Milk basic protein supplementation enhances fracture healing in mice.

OBJECTIVES: There is an unmet need for agents that can stimulate bone healing. The goal of this study was to evaluate the effects of basic proteins from milk whey (milk basic protein [MBP]) on fracture healing in mice. METHODS: Closed tibial transverse fractures were generated in 6-wk-old male C3 H/HeJ mice given either tap water or MBP-supplemented water for 3, 7, 14, 28, and 56 d after fracture generation. The tibial tissues were analyzed by radiography, µCT, and a three-point bending test. The expression levels of genes associated with bone metabolism were analyzed by real-time reverse transcription-polymerase chain reaction. RESULTS: Quantitative µCT analysis showed that MBP-treated fractured tibiae had a larger hard callus in the sectional area and a larger volume compared with fractured tibiae without MBP treatment. The expression levels of genes associated with chondrogenesis and osteogenesis showed greater increases in fractured tibiae with MBP treatment. Significant increases in the callus mechanical properties were found in MBP-treated tibiae. CONCLUSIONS: MBP supplementation has the potential to improve fracture healing and bone strength in mouse tibiae. MBP could be a potential safe, low-cost, and easily administered nutritional element to prevent secondary fractures in patients with bone fractures.