Sodium salicylate is an anti-inflammatory medication with a side-effect of tinnitus. Here, we used mouse cochlear cultures to explore the effects of salicylate treatment on cochlear inner hair cells (IHCs). We found that IHCs showed significant damage after exposure to a high concentration of salicylate. Whole-cell patch clamp recordings showed that 1-5 mmol/L salicylate did not affect the exocytosis of IHCs, indicating that IHCs are not involved in tinnitus generation by enhancing their neuronal input. Instead, salicylate induced a larger peak amplitude, a more negative half-activation voltage, and a steeper slope factor of Ca²⁺ current. Using noise analysis of Ca²⁺ tail currents and qRT-PCR, we further found that salicylate increased the number of Ca²⁺ channels along with Ca_V1.3 expression. All these changes could act synergistically to enhance the Ca²⁺ influx into IHCs. Inhibition of intracellular Ca²⁺ overload significantly attenuated IHC death after 10 mmol/L salicylate treatment. These results implicate a cellular mechanism for tinnitus generation in the peripheral auditory system.
Animals ; Calcium ; Exocytosis ; Hair Cells, Auditory, Inner ; Mice ; Sodium Salicylate/pharmacology* ; Tinnitus/chemically induced*

The exocyst is a highly conserved eight-subunit protein complex (EXOC1–8) involved in the targeting and docking of exocytic vesicles translocating from the trans-Golgi network to various sites in renal cells. EXOC5 is a central exocyst component because it connects EXOC6, bound to the vesicles exiting the trans-Golgi network via the small GTPase RAB8, to the rest of the exocyst complex at the plasma membrane. In the kidney, the exocyst complex is involved in primary ciliognesis, cystogenesis, and tubulogenesis. The exocyst, and its regulators, have also been found in urinary extracellular vesicles, and may be centrally involved in urocrine signaling and repair following acute kidney injury. The exocyst is centrally involved in the development of other organs, including the eye, ear, and heart. The exocyst is regulated by many different small GTPases of the RHO, RAL, RAB, and ARF families. The small GTPases, and their guanine nucleotide exchange factors and GTPase-activating proteins, likely give the exocyst specificity of function. The recent development of a floxed Exoc5 mouse line will aid researchers in studying the role of the exocyst in multiple cells and organ types by allowing for tissue-specific knockout, in conjunction with Cre-driver mouse lines.
Acute Kidney Injury ; Animals ; Cell Membrane ; Ear ; Exocytosis ; Extracellular Vesicles ; GTP Phosphohydrolases ; GTPase-Activating Proteins ; Guanine Nucleotide Exchange Factors ; Heart ; Humans ; Kidney ; Mice ; Monomeric GTP-Binding Proteins ; Sensitivity and Specificity ; trans-Golgi Network

To interact with the egg, the spermatozoon must undergo several biochemical and motility modifications in the female reproductive tract, collectively called capacitation. Only capacitated sperm can undergo acrosomal exocytosis, near or on the egg, a process that allows the sperm to penetrate and fertilize the egg. In the present study, we investigated the involvement of cyclic adenosine monophosphate (cAMP)-dependent processes on acrosomal exocytosis. Inhibition of protein kinase A (PKA) at the end of capacitation induced acrosomal exocytosis. This process is cAMP-dependent; however, the addition of relatively high concentration of the membrane-permeable 8-bromo-cAMP (8Br-cAMP, 0.1 mmol l^-1) analog induced significant inhibition of the acrosomal exocytosis. The induction of acrosomal exocytosis by PKA inhibition was significantly inhibited by an exchange protein directly activated by cAMP (EPAC) ESI09 inhibitor. The EPAC selective substrate activated AE at relatively low concentrations (0.02-0.1 μmol l^-1), whereas higher concentrations (>5 μmol l^-1) were inhibitory to the AE induced by PKA inhibition. Inhibition of PKA revealed about 50% increase in intracellular cAMP levels, conditions under which EPAC can be activated to induce the AE. Induction of AE by activating the actin severing-protein, gelsolin, which causes F-actin dispersion, was inhibited by the EPAC inhibitor. The AE induced by PKA inhibition was mediated by phospholipase C activity but not by the Ca²⁺-channel, CatSper. Thus, inhibition of PKA at the end of the capacitation process induced EPAC/phospholipase C-dependent acrosomal exocytosis. EPAC mediates F-actin depolymerization and/or activation of effectors downstream to F-actin breakdown that lead to acrosomal exocytosis.
8-Bromo Cyclic Adenosine Monophosphate/pharmacology* ; Acrosome/metabolism* ; Acrosome Reaction/drug effects* ; Calcimycin/pharmacology* ; Cyclic AMP/metabolism* ; Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors* ; Exocytosis/drug effects* ; Guanine Nucleotide Exchange Factors/metabolism* ; Humans ; Male ; Protein Kinase Inhibitors/pharmacology* ; Signal Transduction/drug effects* ; Spermatozoa/metabolism* ; Thapsigargin/pharmacology*

BACKGROUND: Acute generalized exanthematous pustulosis (AGEP) is typically a medication-induced acute febrile eruption. Few large-scale studies have reported clinical data regarding AGEP in Korea. OBJECTIVE: This study analyzed the clinical and histopathological features of AGEP in Koreans to identify recent trends in this context. METHODS: This study retrospectively reviewed 31 patients with AGEP. Age, sex, clinical features, etiologies, laboratory findings, histopathological features, and treatment outcomes were obtained from patients' medical records and photographs. RESULTS: The mean age of onset was 43.6 years, and the male:female ratio was 2.1:1. All patients showed non-follicular tiny pustules and erythema. Fever was reported in 13 patients and neutrophilia in 17 patients. Medications were considered the most common etiological contributors. Twenty patients showed drug-induced AGEP, and 11 of 20 patients showed antibiotic-induced AGEP. Serum C-reactive protein and lactate dehydrogenase levels increased in 93.8% and 77.8% of the patients, respectively. Histopathologically, all patients showed subcorneal or intraepidermal pustules, followed by exocytosis and neutrophilic dermal infiltrate. Twenty-five patients improved within a mean period of 7.5 days after the onset of the skin rash. The percentage of women in the drug-induced AGEP group was significantly higher than that in the non-drug-induced AGEP group. CONCLUSION: This report describes a large-scale study that analyzed the clinical and histopathological features of AGEP in Koreans and seems to accurately reflect the recent trends in this context. Clinically, it is important to note that the percentage of women in the drug-induced AGEP group was higher than that in groups showing other etiologies of AGEP.
Acute Generalized Exanthematous Pustulosis* ; Age of Onset ; C-Reactive Protein ; Erythema ; Exanthema ; Exocytosis ; Female ; Fever ; Humans ; Korea ; L-Lactate Dehydrogenase ; Medical Records ; Neutrophils ; Retrospective Studies

BACKGROUND: Cutaneous drug eruption is very common, and its clinical manifestations are variable. Diagnosis of drug eruption is usually based on clinical findings and medication history. To date, few studies have compared the variable histopathologic findings of drug eruption according to medication. OBJECTIVE: We focused on morbilliform eruption among diverse manifestations of drug eruption and investigated the differences in histopathologic findings between antibiotics- and chemotherapeutic-agent-induced morbilliform drug eruption. METHODS: We reviewed medical charts established from March 1998 to August 2016 at our hospital. Inclusion criteria were histopathologically confirmed drug eruptions, clinical demonstrations of typical morbilliform eruptions obtained from medical photographs, and causative drugs identified as chemotherapeutic agents or antibiotics. Immunohistochemical staining was performed and included CD3, CD4, CD8, CD20, CD56, CD68, langerin, CD138, and c-kit. RESULTS: A total of 40 cases (20 cases, chemotherapeutic group; 20 cases, antibiotics group) were included in this study. The most frequent histologic feature of the epidermis was exocytosis (95%) in the chemotherapeutic group and necrotic keratinocytes (100%) in the antibiotics group. Inflammatory infiltration depths were significantly deeper in the antibiotics group than in the chemotherapeutic group. There was no significant difference between the two groups in terms of immunohistochemical staining. CONCLUSION: This study suggested that in patients with morbilliform drug eruption, chemotherapeutic agents cause more superficial inflammation compared to antibiotics. These findings may facilitate the differentiation of the culprit agents of morbilliform drug eruption in cancer patients. Further large, well-designed studies are needed to confirm these findings.
Anti-Bacterial Agents* ; Antineoplastic Agents ; Diagnosis ; Drug Eruptions* ; Epidermis ; Exocytosis ; Humans ; Inflammation ; Keratinocytes

Erlotinib inhibits the epidermal growth factor receptor and is used in patients with various cancers. However, it can affect the epidermis and hair because the receptor is expressed in normal skin cells. A 54-year-old woman with metastatic non-small-cell lung cancer presented with erythematous patches over her entire body and severe hair shedding 2 weeks after starting erlotinib. Histopathological examinations showed lymphocytic exocytosis; perivascular infiltration of lymphohistiocytes and eosinophils in the right arm; and marked infiltration of eosinophils, neutrophils, and lymphohistiocytes in the scalp. Erlotinib discontinuation improved hair loss and skin lesions. Hair loss has been reported in 5% of patients taking erlotinib. Our case was unusual in that there was complete baldness, and to our knowledge, no report of complete hair loss and exanthematous drug eruption after erlotinib treatment has been previously reported. Here, we report a case of severe hair loss with concurrent exanthematous drug eruption that may have been linked to erlotinib hypersensitivity.
Alopecia ; Arm ; Drug Eruptions ; Eosinophils ; Epidermis ; Erlotinib Hydrochloride ; Exocytosis ; Female ; Hair ; Humans ; Hypersensitivity ; Lung Neoplasms ; Middle Aged ; Neutrophils ; Receptor, Epidermal Growth Factor ; Scalp ; Skin

Exosomes are membranous vesicles of 30-150 nm in diameter that are derived from the exocytosis of the intraluminal vesicles of many cell types including immune cells, stem cells, cardiovascular cells and tumor cells. Exosomes participate in intercellular communication by delivering their contents to recipient cells, with or without direct contact between cells, and thereby influence physiological and pathological processes. They are present in various body fluids and contain proteins, nucleic acids, lipids, and microRNAs that can be transported to surrounding cells. Theragnosis is a concept in next-generation medicine that simultaneously combines accurate diagnostics with therapeutic effects. Molecular components in exosomes have been found to be related to certain diseases and treatment responses, indicating that they may have applications in diagnosis via molecular imaging and biomarker detection. In addition, recent studies have reported that exosomes have immunotherapeutic applications or can act as a drug delivery system for targeted therapies with drugs and biomolecules. In this review, we describe the formation, structure, and physiological roles of exosomes. We also discuss their roles in the pathogenesis and progression of diseases including neurodegenerative diseases, cardiovascular diseases, and cancer. The potential applications of exosomes for theragnostic purposes in various diseases are also discussed. This review summarizes the current knowledge about the physiological and pathological roles of exosomes as well as their diagnostic and therapeutic uses, including emerging exosome-based therapies that could not be applied until now.
Body Fluids ; Cardiovascular Diseases ; Diagnosis ; Drug Delivery Systems ; Exocytosis ; Exosomes* ; MicroRNAs ; Molecular Imaging ; Neurodegenerative Diseases ; Nucleic Acids ; Pathologic Processes ; Stem Cells ; Therapeutic Uses

BACKGROUND: The differential diagnosis of psoriasis and seborrheic dermatitis can be difficult when both conditions are localized to the scalp without the involvement of other skin sites. OBJECTIVE: We aimed to evaluate the histopathological differences between psoriasis and seborrheic dermatitis on the scalp and identify favorable criteria for their differential diagnosis. METHODS: We evaluated 15 cases of psoriasis and 20 cases of seborrheic dermatitis of the scalp that had been clinicopathologically diagnosed. Skin biopsy sections stained with H&E were examined. Additional immunohistochemistry was performed, including Ki-67, keratin 10, caspase-5, and GLUT-1. RESULTS: On histopathological examination, mounds of parakeratosis with neutrophils, spongiform micropustules of Kogoj, and clubbed and evenly elongated rete ridges were significantly more frequently observed in psoriasis. Follicular plugging, shoulder parakeratosis and prominent lymphocytic exocytosis were significantly more common in seborrheic dermatitis. Moreover, significantly higher mitotic figures were observed in psoriatic lesions than in seborrheic dermatitis. Immunohistochemistry did not show any difference between psoriasis and seborrheic dermatitis. CONCLUSION: Histopathological features favoring psoriasis include mounds of parakeratosis with neutrophils, spongiform micropustules of Kogoj, clubbed and evenly elongated rete ridges, and increased mitotic figures (≥6/high-powered field). Features indicating seborrheic dermatitis are follicular plugging, shoulder parakeratosis and prominent lymphocytic exocytosis. Immunohistochemistry was not helpful in differentiating psoriasis from seborrheic dermatitis.
Biopsy ; Dermatitis, Seborrheic* ; Diagnosis, Differential* ; Exocytosis ; Immunohistochemistry ; Keratin-10 ; Neutrophils ; Parakeratosis ; Psoriasis* ; Scalp* ; Shoulder ; Skin

The present study was designed to investigate the characteristics of gintonin, one of components isolated from Korean Ginseng on secretion of catecholamines (CA) from the isolated perfused model of rat adrenal gland and to clarify its mechanism of action. Gintonin (1 to 30 µg/ml), perfused into an adrenal vein, markedly increased the CA secretion from the perfused rat adrenal medulla in a dose-dependent fashion. The gintonin-evoked CA secretion was greatly inhibited in the presence of chlorisondamine (1 µM, an autonomic ganglionic bloker), pirenzepine (2 µM, a muscarinic M₁ receptor antagonist), Ki14625 (10 µM, an LPA₁/₃ receptor antagonist), amiloride (1 mM, an inhibitor of Na⁺/Ca²⁺ exchanger), a nicardipine (1 µM, a voltage-dependent Ca²⁺ channel blocker), TMB-8 (1 µM, an intracellular Ca²⁺ antagonist), and perfusion of Ca²⁺-free Krebs solution with 5mM EGTA (a Ca²⁺chelater), while was not affected by sodium nitroprusside (100 µM, a nitrosovasodialtor). Interestingly, LPA (0.3~3 µM, an LPA receptor agonist) also dose-dependently enhanced the CA secretion from the adrenal medulla, but this facilitatory effect of LPA was greatly inhibited in the presence of Ki 14625 (10 µM). Moreover, acetylcholine (AC)-evoked CA secretion was greatly potentiated during the perfusion of gintonin (3 µg/ml). Taken together, these results demonstrate the first evidence that gintonin increases the CA secretion from the perfused rat adrenal medulla in a dose-dependent fashion. This facilitatory effect of gintonin seems to be associated with activation of LPA- and cholinergic-receptors, which are relevant to the cytoplasmic Ca²⁺ increase by stimulation of the Ca²⁺ influx as well as by the inhibition of Ca²⁺ uptake into the cytoplasmic Ca²⁺ stores, without the increased nitric oxide (NO). Based on these results, it is thought that gintonin, one of ginseng components, can elevate the CA secretion from adrenal medulla by regulating the Ca²⁺ mobilization for exocytosis, suggesting facilitation of cardiovascular system. Also, these findings show that gintonin might be at least one of ginseng-induced hypertensive components.
Acetylcholine ; Adrenal Glands ; Adrenal Medulla* ; Amiloride ; Animals ; Cardiovascular System ; Catecholamines ; Chlorisondamine ; Cytoplasm ; Egtazic Acid ; Exocytosis ; Ganglia, Autonomic ; Nicardipine ; Nitric Oxide ; Nitroprusside ; Panax ; Perfusion ; Pirenzepine ; Rats ; Veins

Mast cells are primary mediators of allergic inflammation. Beta-1,3-glucan (BG) protects against infection and shock by activating immune cells. Activation of the BG receptor induces an increase in intracellular Ca2+, which may induce exocytosis. However, little is known about the precise mechanisms underlying BG activation of immune cells and the possible role of mitochondria in this process. The present study examined whether BG induced mast cell degranulation, and evaluated the role of calcium transients during mast cell activation. Our investigation focused on the role of the mitochondrial calcium uniporter (MCU) in BG-induced degranulation. Black mouse (C57) bone marrow-derived mast cells were stimulated with 0.5 microg/ml BG, 100 microg/ml peptidoglycan (PGN), or 10 microM A23187 (calcium ionophore), and dynamic changes in cytosolic and mitochondrial calcium and membrane potential were monitored. BG-induced mast cell degranulation occurred in a time-dependent manner, and was significantly reduced under calcium-free conditions. Ruthenium red, a mitochondrial Ca2+ uniporter blocker, significantly reduced mast cell degranulation induced by BG, PGN, and A23187. These results suggest that the mitochondrial Ca2+ uniporter has an important regulatory role in BG-induced mast cell degranulation.
Animals ; Calcimycin ; Calcium* ; Cytosol ; Exocytosis ; Inflammation ; Ion Transport* ; Mast Cells* ; Membrane Potentials ; Mice* ; Mitochondria ; Peptidoglycan ; Ruthenium Red ; Shock