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Background Lung toxicity in patients undergoing cetuximab and radiotherapy (Cetux-RT) for head and neck squamous cell carcinoma (HNSCC) has been reported in literature and represents a serious side effect of concurrent therapies. Methods We report a case of a HNSCC patient that developed neck emphysema during the course of Cetux-RT. The patient was an old male (80 years old) in a good performance status, with an oropharyngeal cancer (T4aN3a). Results During RT, cone-beam computed tomography (CBCT) showed bilateral neck emphysema that was confirmed at restaging CT. We decided to stop the treatment and to treat the neck emphysema with conservative strategies. After one week CT was repeated and the neck emphysema had improved, so we decided to complete the RT treatment. Conclusions Patients undergoing Cetux-RT must be properly selected, whereas IGRT imaging must be viewed carefully in order to permit an early diagnosis and careful management of the patients.

Vestibular paroxysmia (also known as disabling positional vertigo) is a clinical syndrome generated by a symptomatic neurovascular compression of the eighth cranial nerve. Although doubted by some authors, this syndrome must be suspected in presence of brief spells of positional vestibular symptoms associated with temporary or permanent but worsening cochleovestibular symptoms and signs, not explained by other diseases. We report a case of a 20-year-old girl affected by permanent sensorineural hearing loss on the right since the age of 4-5 year, who subsequently developed intermittent low pitch tinnitus on the right ear and spells of vertigo or dizziness generated by position or physical activity. Angio-MRI of the brain showed a singular neurovascular contact between the right vertebral artery and the right eighth cranial nerve. The excellent response to carbamazepine confirms the presence of this syndrome.

Laryngeal neuroendocrine carcinomas (LNECs) are rare and highly heterogeneous malignancies presenting a wide range of pathological and clinical manifestations. Herein, we retrospectively characterize ten patients diagnosticated with LNEC, five of which were defined as well-moderately differentiated neuroendocrine carcinomas, and five that were defined as poorly differentiated neuroendocrine carcinomas, according to the latest WHO classification. Clinical features were analyzed and compared between the two subgroups together with a microRNA study which evidenced a peculiar signature likely related to poorly differentiated larynx neuroendocrine carcinomas. These findings may offer new useful insights for clinicians to improve diagnosis efficiency, therapy response, and patients’ outcome for this aggressive neoplasm.

Ca 2+ ‐sensor proteins are generally implicated in insulin release through SNARE interactions. Here, secretagogin, whose expression in human pancreatic islets correlates with their insulin content and the incidence of type 2 diabetes, is shown to orchestrate an unexpectedly distinct mechanism. Single‐cell RNA‐seq reveals retained expression of the TRP family members in β‐cells from diabetic donors. Amongst these, pharmacological probing identifies Ca 2+ ‐permeable transient receptor potential vanilloid type 1 channels (TRPV1) as potent inducers of secretagogin expression through recruitment of Sp1 transcription factors. Accordingly, agonist stimulation of TRPV1s fails to rescue insulin release from pancreatic islets of glucose intolerant secretagogin knock‐out( −/− ) mice. However, instead of merely impinging on the SNARE machinery, reduced insulin availability in secretagogin −/− mice is due to β‐cell loss, which is underpinned by the collapse of protein folding and deregulation of secretagogin‐dependent USP9X deubiquitinase activity. Therefore, and considering the desensitization of TRPV1s in diabetic pancreata, a TRPV1‐to‐secretagogin regulatory axis seems critical to maintain the structural integrity and signal competence of β‐cells.

The rostral migratory stream (RMS) is viewed as a glia-enriched conduit of forward-migrating neuroblasts in which chemorepulsive signals control the pace of forward migration. Here we demonstrate the existence of a scaffold of neurons that receive synaptic inputs within the rat, mouse, and human fetal RMS equivalents. These neurons express secretagogin, a Ca2+-sensor protein, to execute an annexin V-dependent externalization of matrix metalloprotease-2 (MMP-2) for reconfiguring the extracellular matrix locally. Mouse genetics combined with pharmacological probing in vivo and in vitro demonstrate that MMP-2 externalization occurs on demand and that its loss slows neuroblast migration. Loss of function is particularly remarkable upon injury to the olfactory bulb. Cumulatively, we identify a signaling cascade that provokes structural remodeling of the RMS through recruitment of MMP-2 by a previously unrecognized neuronal constituent. Given the life-long presence of secretagogin-containing neurons in human, this mechanism might be exploited for therapeutic benefit in rescue strategies.

Lipid metabolism is critical to coordinate organ development and physiology in response to tissue-autonomous signals and environmental cues. Changes to the availability and signaling of lipid mediators can limit competitiveness, adaptation to environmental stressors, and augment pathological processes. Two classes of lipids, the N-acyl amides and the 2-acyl glycerols, have emerged as important signaling molecules in a wide range of species with important signaling properties, though most of what is known about their cellular functions is from mammalian models. Therefore, expanding available knowledge on the repertoire of these lipids in invertebrates will provide additional avenues of research aimed at elucidating biosynthetic, metabolic, and signaling properties of these molecules. Drosophila melanogaster is a commonly used organism to study intercellular communication, including the functions of bioactive lipids. However, limited information is available on the molecular identity of lipids with putative biological activities in Drosophila. Here, we used a targeted lipidomics approach to identify putative signaling lipids in third instar Drosophila larvae, possessing particularly large lipid mass in their fat body. We identified 2-linoleoyl glycerol, 2-oleoyl glycerol, and 45 N-acyl amides in larval tissues, and validated our findings by the comparative analysis of Oregon-RS, Canton-S and w1118 strains. Data here suggest that Drosophila represent another model system to use for the study of 2-acyl glycerol and N-acyl amide signaling.

Background: Secretagogin (Scgn), a member of the EF-hand calcium-binding protein (CaBP) superfamily, has recently been found in subsets of developing and adult neurons. Here, we have analyzed the expression of Scgn in dorsal root ganglia (DRGs) and trigeminal ganglia (TGs), and in spinal cord of mouse at the mRNA and protein levels, and in comparison to the well-known CaBPs, calbindin D-28k, parvalbumin and calretinin. Rat DRGs, TGs and spinal cord, as well as human DRGs and spinal cord were used to reveal phylogenetic variations. Results: We found Scgn mRNA expressed in mouse and human DRGs and in mouse ventral spinal cord. Our immunohistochemical data showed a complementary distribution of Scgn and the three CaBPs in mouse DRG neurons and spinal cord. Scgn was expressed in ∼7% of all mouse DRG neuron profiles, mainly small ones and almost exclusively co-localized with calcitonin gene-related peptide (CGRP). This co-localization was also seen in human, but not in rat DRGs. Scgn could be detected in the mouse sciatic nerve and accumulated proximal to its constriction. In mouse spinal cord, Scgn-positive neuronal cell bodies and fibers were found in gray matter, especially in the dorsal horn, with particularly high concentrations of fibers in the superficial laminae, as well as in cell bodies in inner lamina II and in some other laminae. A dense Scgn-positive fiber network and some small cell bodies were also found in the superficial dorsal horn of humans. In the ventral horn, a small number of neurons were Scgn-positive in mouse but not rat, confirming mRNA distribution. Both in mouse and rat, a subset of TG neurons contained Scgn. Dorsal rhizotomy strongly reduced Scgn fiber staining in the dorsal horn. Peripheral axotomy did not clearly affect Scgn expression in DRGs, dorsal horn or ventral horn neurons in mouse. Conclusions: Scgn is a CaBP expressed in a subpopulation of nociceptive DRG neurons and their processes in the dorsal horn of mouse, human and rat, the former two co-expressing CGRP, as well as in dorsal horn neurons in all three species. Functional implications of these findings include the cellular refinement of sensory information, in particular during the processing of pain.

Endocannabinoids, particularly 2-arachidonoyl glycerol (2-AG), impact the directional turning and motility of a developing axon by activating CB1cannabinoid receptors (CB1Rs) in its growth cone. Recent findings posit thatsn-1-diacylglycerol lipases (DAGLα/β) synthesize 2-AG in the motile axon segment of developing pyramidal cells. Coincident axonal targeting of CB1Rs and DAGLs prompts the hypothesis that autocrine 2-AG signaling facilitates axonal outgrowth. However, DAGLs alone are insufficient to account for the spatial specificity and dynamics of 2-AG signaling. Therefore, we hypothesized that local 2-AG degradation by monoacylglycerol lipase (MGL) must play a role. We determined how subcellular recruitment of MGL is temporally and spatially restricted to establish the signaling competence of 2-AG during axonal growth. MGL is expressed in central and peripheral axons of the fetal nervous system by embryonic day 12.5. MGL coexists with DAGLα and CB1Rs in corticofugal axons of pyramidal cells. Here, MGL and DAGLα undergo differential axonal targeting with MGL being excluded from the motile neurite tip. Thus, spatially confined MGL activity generates a 2-AG-sensing microdomain and configures 2-AG signaling to promote axonal growth. Once synaptogenesis commences, MGL disperses in stationary growth cones. The axonal polarity of MGL is maintained by differential proteasomal degradation because inhibiting the ubiquitin proteasome system also induces axonal MGL redistribution. Because MGL inactivation drives a CB1R-dependent axonal growth response, we conclude that 2-AG may act as a focal protrusive signal for developing neurons and whose regulated metabolism is critical for attaining correct axonal complexity.

The Ca 2+ -binding proteins (CBPs) parvalbumin, calbindin, and calretinin are phenotypic markers of terminally differentiated neurons in the adult brain. Although subtle phylogenetic variations in the neuronal distribution of these CBPs may occur, morphologically and functionally diverse subclasses of interneurons harbor these proteins in olfactory and corticolimbic areas. Secretagogin (scgn) is a recently cloned CBP from pancreatic β and neuroendocrine cells. We hypothesized that scgn is expressed in the mammalian brain. We find that scgn is a marker of neuroblasts commuting in the rostral migratory stream. Terminally differentiated neurons in the olfactory bulb retain scgn expression, with scgn being present in periglomerular cells and granular layer interneurons. In the corticolimbic system, scgn identifies granule cells distributed along the dentate gyrus, indusium griseum, and anterior hippocampal continuation emphasizing the shared developmental origins, and cytoarchitectural and functional similarities of these neurons. We also uncover unexpected phylogenetic differences in scgn expression, since this CBP is restricted to primate cholinergic basal forebrain neurons. Overall, we characterize scgn as a neuron-specific CBP whose distribution identifies neuronal subtypes and hierarchical organizing principles in the mammalian brain.

Introduction: In mammals, sn-1-diacylglycerol lipases (DAGL) generate 2-arachidonoylglycerol (2-AG) that, as the major endocannabinoid, modulates synaptic neurotransmission by acting on CB1 cannabinoid receptors (CB1R). Even though the insect genome codes for inaE, which is a DAGL ortholog (dDAGL), its products and their functions remain unknown particularly because insects lack chordate-type cannabinoid receptors. Materials and Methods: Gain-of-function and loss-of-function genetic manipulations were carried out in Drosophila melanogaster, including the generation of both dDAGL-deficient and mammalian CB1R-overexpressing flies. Neuroanatomy, dietary manipulations coupled with targeted mass spectrometry determination of arachidonic acid and 2-linoleoyl glycerol (2-LG) production, behavioral assays, and signal transduction profiling for Akt and Erk kinases were employed. Findings from Drosophilae were validated by a CB1R-binding assay for 2-LG in mammalian cortical homogenates with functionality confirmed in neurons using high-throughput real-time imaging in vitro. Results: In this study, we show that dDAGL is primarily expressed in the brain and nerve cord of Drosophila during larval development and in adult with 2-LG being its chief product as defined by dietary precursor availability. Overexpression of the human CB1R in the ventral nerve cord compromised the mobility of adult Drosophilae. The causality of 2-LG signaling to CB1R-induced behavioral impairments was shown by inaE inactivation normalizing defunct motor coordination. The 2-LG-induced activation of transgenic CB1Rs affected both Akt and Erk kinase cascades by paradoxical signaling. Data from Drosophila models were substantiated by showing 2-LG-mediated displacement of [3H]CP 55,940 in mouse cortical homogenates and reduced neurite extension and growth cone collapsing responses in cultured mouse neurons. Conclusions: Overall, these results suggest that 2-LG is an endocannabinoid-like signal lipid produced by dDAGL in Drosophila.

Endocannabinoid, particularly 2-arachidonoyl glycerol (2-AG), signaling has recently emerged as a molecular determinant of neuronal migration and synapse formation during cortical development. However, the cell type specificity and molecular regulation of spatially and temporally confined morphogenic 2-AG signals remain unexplored. Here, we demonstrate that genetic and pharmacological manipulation of CB 1 cannabinoid receptors permanently alters cholinergic projection neuron identity and hippocampal innervation. We show that nerve growth factor (NGF), implicated in the morphogenesis and survival of cholinergic projection neurons, dose-dependently and coordinately regulates the molecular machinery for 2-AG signaling via tropomyosine kinase A receptors in vitro. In doing so, NGF limits the sorting of monoacylglycerol lipase (MGL), rate limiting 2-AG bioavailability, to proximal neurites, allowing cell-autonomous 2-AG signaling at CB 1 cannabinoid receptors to persist at atypical locations to induce superfluous neurite extension. We find that NGF controls MGL degradation in vitro and in vivo and identify the E3 ubiquitin ligase activity of breast cancer type 1 susceptibility protein (BRCA1) as a candidate facilitating MGL’s elimination from motile neurite segments, including growth cones. BRCA1 inactivation by cisplatin or genetically can rescue and reposition MGL, arresting NGF-induced growth responses. These data indicate that NGF can orchestrate endocannabinoid signaling to promote cholinergic differentiation and implicate BRCA1 in determining neuronal morphology.