CLIC4 Function in the Epithelial-Mesenchymal Transition of Epithelial Odontogenic Lesions.

BACKGROUND: Odontogenic lesions constitute a heterogeneous group of lesions. CLIC4 protein regulates different cellular processes, including epithelial-mesenchymal transition and fibroblast-myofibroblast transdifferentiation. This study analyzed CLIC4, E-cadherin, Vimentin, and α-SMA immunoexpression in epithelial odontogenic lesions that exhibit different biological behavior. METHODS: It analyzed the immunoexpression of CLIC4, E-cadherin, and Vimentin in the epithelial cells, as well as CLIC4 and α-SMA in the mesenchymal cells, of ameloblastoma (AM) (n = 16), odontogenic keratocyst (OKC) (n = 20), and adenomatoid odontogenic tumor (AOT) (n = 8). Immunoexpressions were categorized as score 0 (0% positive cells), 1 (< 25%), 2 (≥ 25% - < 50%), 3 (≥ 50% - < 75%), or 4 (≥ 75%). RESULTS: Cytoplasmic CLIC4 immunoexpression was higher in AM and AOT (p < 0.001) epithelial cells. Nuclear-cytoplasmic CLIC4 was higher in OKC's epithelial lining (p < 0.001). Membrane (p = 0.012) and membrane-cytoplasmic (p < 0.001) E-cadherin immunoexpression were higher in OKC, while cytoplasmic E-cadherin expression was higher in AM and AOT (p < 0.001). Vimentin immunoexpression was higher in AM and AOT (p < 0.001). Stromal CLIC4 was higher in AM and OKC (p = 0.008). Similarly, α-SMA immunoexpression was higher in AM and OKC (p = 0.037). Correlations in these proteins' immunoexpression were observed in AM and OKC (p < 0.05). CONCLUSIONS: CLIC4 seems to regulate the epithelial-mesenchymal transition, modifying E-cadherin and Vimentin expression. In mesenchymal cells, CLIC4 may play a role in fibroblast-myofibroblast transdifferentiation. CLIC4 may be associated with epithelial odontogenic lesions with aggressive biological behavior.

Chloride intracellular channel 4 (CLIC4) expression profile in the mouse medial prefrontal cortex and its regulation by ethanol.

BACKGROUND: Chloride intracellular channel 4 (CLIC4) is a multifunctional metamorphic protein for which a growing body of evidence supports a major role in the brain's molecular and behavioral responses to ethanol (EtOH). Although key to understanding the functional biology underlying this role, little is known about the cellular and subcellular expression patterns of CLIC4 in brain and how they are affected by EtOH. METHODS: We used qRT-PCR to assess Clic4 mRNA expression in the medial prefrontal cortex (mPFC) of C57BL/6J mice in the absence and presence of acute EtOH exposure. Two complementary immunohistochemical techniques were employed to assess the subcellular localization of the CLIC4 protein and its pattern of expression across brain cell types in the mPFC in the absence and presence of acute EtOH. RESULTS: Through immunohistochemical and stereological techniques, we show that CLIC4 protein is robustly expressed by oligodendrocytes (most abundant), microglia, and astrocytes, with minimal expression in neurons. Following acute EtOH exposure, we observed a rapid increase in Clic4 mRNA expression in female but not male mice and an overall increase in the number of oligodendrocytes and astrocytes expressing the CLIC4 protein. CONCLUSIONS: These findings suggest that Clic4 functions as an early response gene for acute EtOH in brain, which likely underlies its ability to modulate EtOH behavior. Our results also suggest that the role of CLIC4 in the brain's response to EtOH is mediated through oligodendrocytes.

Cl- and H+ coupling properties and subcellular localizations of wildtype and disease-associated variants of the voltage-gated Cl-/H+ exchanger ClC-5.

Dent disease 1 (DD1) is caused by mutations in the CLCN5 gene encoding a voltage-gated electrogenic nCl-/H+ exchanger ClC-5. Using ion-selective microelectrodes and Xenopus oocytes, here we studied Cl-/H+ coupling properties of WT ClC-5 and four DD1-associated variants (S244L, R345W, Q629*, and T657S), along with trafficking and localization of ClC-5. WT ClC-5 had a 2Cl-/H+ exchange ratio at a Vh of +40 mV with a [Cl-]out of 104 mm, but the transport direction did not reverse with a [Cl-]out of 5 mm, indicating that ClC-5-mediated exchange of two Cl- out for one H+ in is not permissible. We hypothesized that ClC-5 and H+-ATPase are functionally coupled during H+-ATPase-mediated endosomal acidification, crucial for ClC-5 activation by depolarizing endosomes. ClC-5 transport that provides three net negative charges appeared self-inhibitory because of ClC-5's voltage-gated properties, but shunt conductance facilitated further H+-ATPase-mediated endosomal acidification. Thus, an on-and-off "burst" of ClC-5 activity was crucial for preventing Cl- exit from endosomes. The subcellular distribution of the ClC-5:S244L variant was comparable with that of WT ClC-5, but the variant had a much slower Cl- and H+ transport and displayed an altered stoichiometry of 1.6:1. The ClC-5:R345W variant exhibited slightly higher Cl-/H+ transport than ClC-5:S244L, but co-localized with early endosomes, suggesting decreased ClC-5:R345W membrane trafficking is perhaps in a fully functional form. The truncated ClC-5:Q629* variant displayed the lowest Cl-/H+ exchange and was retained in the endoplasmic reticulum and cis-Golgi, but not in early endosomes, suggesting the nonsense mutation affects ClC-5 maturation and trafficking.

Diagnosis of thymic epithelial tumor subtypes by a quantitative proteomic approach.

The histological typing of thymic epithelial tumours (TETs) still remains a challenge for surgical pathologists, especially when encountering borderline cases mainly focused on spindle cell types (including type A, atypical type A (aA), AB, and B3). A systematic proteomics analysis of TETs was performed using isobaric tags for relative and absolute quantification (iTRAQ) labeling coupled with two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS). In total, 6479 and 6305 proteins were identified and quantified, respectively. After Gene Ontology (GO) annotation and Ingenuity Pathway Analysis (IPA), six differentially expressed proteins were validated by tissue microarray or multiple reaction monitoring (MRM) quantification. ABCE1 and CLIC2 are promising to be diagnostic candidate biomarkers in thymic carcinomas (TCs). CHD1L was up-regulated in type AB and type B thymomas compared with type A thymoma. Both CLIC2 and MAP7 were negatively detected in type B1 and B2 thymomas. SMAD4 was overexpressed in type aA thymomas and TCs. CDC42 was significantly down-regulated in type B2 thymomas compared with other subtypes. Six novel candidate biomarkers were found to be useful in differentiating subtypes of TETs. SMAD4 may play a specific role in tumorigenesis and the development of aA thymomas and thymic carcinomas.

BSND is a Novel Immunohistochemical Marker for Oncocytic Salivary Gland Tumors.

BSND protein, which is involved in chloride transport, is expressed in normal kidney and the inner ear and is known as an immunohistochemical marker for chromophobe renal cell carcinoma (RCC) and renal oncocytoma; however, other organs and tumor types exhibiting BSND expression have not yet been reported. In this study, we investigated the expression of BSND using data from the Cancer Genome Atlas (TCGA) database and by performing immunohistochemical analyses. As a result, we found that BSND was also expressed in the striated duct cells of normal salivary glands. Next, BSND expression was examined immunohistochemically in 7 types of salivary gland tumors, and BSND positivity was found in Warthin's tumor (25 out of 25 cases; 100%) and oncocytoma (4/4; 100%), both of which are usually classified as oncocytic tumors, whereas BSND negativity was observed for pleomorphic adenoma (0/11), adenoid cystic carcinoma (0/7), acinic cell carcinoma (0/6), mucoepidermoid carcinoma (0/6), and salivary duct carcinoma (0/5). Finally, the expression of BSND mRNA in 30 types of tumors other than chromophobe RCC and salivary gland tumors was examined using data from the TCGA database, but none of these tumors exhibited BSND expression. These results suggest that BSND is expressed only in normal salivary glands and oncocytic salivary gland tumors such as Warthin's tumor and oncocytoma in addition to the two known organs and the two known renal tumor types mentioned above. The selective expression pattern of BSND suggests that BSND is an excellent novel immunohistochemical marker for oncocytic salivary gland tumors.

Preferential association with ClC-3 permits sorting of ClC-4 into endosomal compartments.

ClC-4 is an intracellular Cl-/H+ exchanger that is highly expressed in the brain and whose dysfunction has been linked to intellectual disability and epilepsy. Here we studied the subcellular localization of human ClC-4 in heterologous expression systems. ClC-4 is retained in the endoplasmic reticulum (ER) upon overexpression in HEK293T cells. Co-expression with distinct ClC-3 splice variants targets ClC-4 to late endosome/lysosomes (ClC-3a and ClC-3b) or recycling endosome (ClC-3c). When expressed in cultured astrocytes, ClC-4 sorted to endocytic compartments in WT cells but was retained in the ER in Clcn3-/- cells. To understand the virtual absence of ER-localized ClC-4 in WT astrocytes, we performed association studies by high-resolution clear native gel electrophoresis. Although other CLC channels and transporters form stable dimers, ClC-4 was mostly observed as monomer, with ClC-3-ClC-4 heterodimers being more stable than ClC-4 homodimers. We conclude that unique oligomerization properties of ClC-4 permit regulated targeting of ClC-4 to various endosomal compartment systems via expression of different ClC-3 splice variants.

Expression of anoctamin 1 is associated with advanced tumor stage in patients with non-small cell lung cancer and predicts recurrence after surgery

Purpose. Anoctamin 1 (ANO1), a recently identified calcium-activated chloride channel, has been found to have a critical role in tumorigenesis and tumor progression in several types of cancer. However, its role in non-small cell lung cancer (NSCLC) remains to be elucidated. In this study, we evaluated the utility of ANO1 as a prognostic marker. Patients and methods. ANO1 expression was detected in tumor tissues and paraneoplastic tissues of I-IV stage NSCLC patients who received surgical treatment by using immunohistochemical and quantitative RT-PCR analyses. Epidermal growth factor receptor (EGFR) was investigated using immunohistochemistry. Then the TNM stage of the tumor samples was assessed and patients were followed up for developing recurrence. Results. ANO1 expression was significantly increased in NSCLC tumor tissues compared to the paraneoplastic tissues at both RNA and protein level. In addition, ANO1 overexpression was correlated with the high expression of EGFR and led to an advanced tumor stage. And also high ANO1 expression was significantly correlated with high recurrence rate at 1-year follow-up. Conclusions. ANO1 overexpression associated with the high expression of EGFR can be a predictive marker of recurrence after surgery in NSCLC patients (AU)

No disponible

The stoichiometry of the TMEM16A ion channel determined in intact plasma membranes of COS-7 cells using liquid-phase electron microscopy.

TMEM16A is a membrane protein forming a calcium-activated chloride channel. A homodimeric stoichiometry of the TMEM16 family of proteins has been reported but an important question is whether the protein resides always in a dimeric configuration in the plasma membrane or whether monomers of the protein are also present in its native state within in the intact plasma membrane. We have determined the stoichiometry of the human (h)TMEM16A within whole COS-7 cells in liquid. For the purpose of detecting TMEM16A subunits, single proteins were tagged by the streptavidin-binding peptide within extracellular loops accessible by streptavidin coated quantum dot (QD) nanoparticles. The labeled proteins were then imaged using correlative light microscopy and environmental scanning electron microscopy (ESEM) using scanning transmission electron microscopy (STEM) detection. The locations of 19,583 individual proteins were determined of which a statistical analysis using the pair correlation function revealed the presence of a dimeric conformation of the protein. The amounts of detected label pairs and single labels were compared between experiments in which the TMEM16A SBP-tag position was varied, and experiments in which tagged and non-tagged TMEM16A proteins were present. It followed that hTMEM16A resides in the plasma membrane as dimer only and is not present as monomer. This strategy may help to elucidate the stoichiometry of other membrane protein species within the context of the intact plasma membrane in future.

GIST Manifesting as a Retroperitoneal Tumor: Clinicopathologic Immunohistochemical, and Molecular Genetic Study of 112 Cases.

Most gastrointestinal stromal tumors (GISTs) occur in the tubular gastrointestinal (GI) tract, but some present apparently outside the GI tract. In this study, we analyzed 112 GISTs located in the retroperitoneum. These tumors occurred in 55 women and 57 men with a median age of 65 years (range: 21 to 89 y). On the basis of clinically or histologically detected connections to GI tract, 15 tumors were considered likely of gastric, 9 duodenal, and 13 of small intestinal origin. The remaining cases were categorized by location as peripancreatic (n=25), pelvic (n=11), mesenteric (n=4), and of unspecified/miscellaneous sites (n=35). The tumors varied in size 3 to 35 cm (median, 15 cm) and by mitotic rate per 5 mm, 0 to >100 (median, 10). Histologically the tumors apparently arising outside the GI tract had features of intestinal (n=41) and gastric GISTs (n=25); 9 cases had indeterminate histology. The histologic variants included spindled, epithelioid, vacuolated, nested, and myxoid potentially simulating other tumors such as liposarcoma and solitary fibrous tumor. Most GISTs were KIT-positive (106/112 cases), and the remaining 6 tumors were DOG1/Ano1-positive. Five cases showed focal nuclear positivity for MDM2. KIT mutations were detected in 42/59 cases, and PDGFRA mutations in 4/16 KIT wild-type and 3/5 of the KIT-negative tumors analyzed. One pelvic retroperitoneal GIST was succinate dehydrogenase deficient. All 79 patients were dead at last follow-up with a median survival of 14 months, with few survivals >5 years. Only operable versus inoperable tumor was a statistically favorable factor in univariate analysis (P<0.01). In multivariate analysis, mitotic rate >50/5 mm was significant for a shorter survival (hazard ratio, 5.25; 95% confidence interval, 1.65-16.8; P<0.01). Histologic and clinicopathologic similarity of extragastrointestinal retroperitoneal GISTs with GISTs of GI tract suggests their GI tract origin. Potentially overlapping features between GIST and other retroperitoneal tumors necessitate use of multiple diagnostic markers and molecular genetic studies.

The Diagnostic and Prognostic Utility of DOG1 Expression on Gastrointestinal Stromal Tumors.

OBJECTIVE: We aimed to review our archives in order to evaluate both the diagnostic and prognostic significance of DOG1 on gastrointestinal stromal tumors (GISTs), and add further insight about those issues to the current literature including some conflicting results. MATERIAL AND METHOD: DOG1 was evaluated in 100 cases of GISTs, immunohistochemically. Immunostaining index was counted for each antibody by using both the intensity and extent of staining. The association between immunostaining index of DOG1 and CD117, CD34, SMA desmin, S-100, and Ki-67 index and clinicopathological features were analyzed. RESULTS: Ninety cases were positive for DOG1, and 89 were positive for CD117. All CD117-negative tumors were positive for DOG1. High-risk group was directly correlated with tumor diameter, cellularity, necrosis, nuclear pleomorphism, mitotic count and Ki-67 index, by univariate analysis. The association between high-risk group and tumor diameter, mitotic count, and Ki-67 index was proved by multivariate analysis. Immunostaining index of DOG1, Ki-67 index, mitotic count, ulceration and hemorrhage were inversely correlated with overall survival by univariate analysis. The adverse impact of DOG1 ISI and mitotic count on overall survival were supported by multivariate analysis. CONCLUSION: DOG1 positivity was detected in most of GISTs and all in CD117-negative cases as a result underlining its diagnostic utility. Additionally, DOG1 overexpression was related with adverse prognosis. Thus, we suggest that immunostaining index of DOG1 should routinely be used while diagnosing GIST, and DOG1 might be considered as a potential prognostic tool and a target for novel therapies.

Combined DOG1 and Mammaglobin Immunohistochemistry Is Comparable to ETV6-breakapart Analysis for Differentiating Between Papillary Cystic Variants of Acinic Cell Carcinoma and Mammary Analogue Secretory Carcinoma.

BACKGROUND: We investigated the reliability of combined DOG1 and mammaglobin immunohistochemistry compared with ETV6 fluorescence in situ hybridization (FISH) in the assessment of salivary tumors previously diagnosed as acinic cell carcinoma (ACC). Ultrastructural features of cases reclassified as mammary analogue secretory carcinoma (MASC) were assessed by transmission electron microscopy (TEM). METHODS: Immunohistochemical (IHC) reactivity to DOG1 and mammaglobin was validated against FISH targeting the ETV6 gene in all 14 cases. RESULTS: Three cases with papillary cystic histomorphology previously diagnosed as ACC were revised to MASC. TEM features of the ETV6 rearrangement-positive MASC cases showed large numbers of secretory granules with extrusion into the intercellular spaces, well-developed endoplasmic reticulum, lipid-laden vacuoles, well-formed microvilli, and large lining cystic spaces. CONCLUSIONS: Combined DOG1 and mammaglobin immunohistochemistry is comparable to ETV6 -breakapart analysis for differentiating between papillary cystic variants of ACC and MASC.

The presence and role of interstitial cells of Cajal in the proximal intestine of shorthorn sculpin (Myoxocephalus scorpius).

Rhythmic contractions of the mammalian gastrointestinal tract can occur in the absence of neuronal or hormonal stimulation owing to the generation of spontaneous electrical activity by interstitial cells of Cajal (ICC) that are electrically coupled to smooth muscle cells. The myogenically driven component of gastrointestinal motility patterns in fish probably also involves ICC; however, little is known of their presence, distribution and function in any fish species. In the present study, we combined immunohistochemistry and in vivo recordings of intestinal motility to investigate the involvement of ICC in the motility of the proximal intestine in adult shorthorn sculpin (Myoxocephalus scorpius). Antibodies against anoctamin 1 (Ano1, a Ca2+-activated Cl- channel), revealed a dense network of multipolar, repeatedly branching cells in the myenteric region of the proximal intestine, similar in many regards to the mammalian ICC-MY network. The addition of benzbromarone, a potent blocker of Ano1, altered the motility patterns seen in vivo after neural blockade with TTX. The results indicate that ICC are integral for the generation and propagation of the majority of rhythmic contractile patterns in fish, although their frequency and amplitude can be modulated via neural activity.

Expression of DOG1 (Using SP31) in Poorly Differentiated Carcinoma of the Head and Neck.

BACKGROUND: The calcium-activated chloride channel protein discovered on gastrointestinal stromal tumour 1 (DOG1) is expressed in a variety of normal and neoplastic tissues. DOG1 is a specific marker for gastrointestinal stromal tumour. In the head and neck region, DOG1 is a sensitive discriminator for acinar cell carcinoma. Only a few publications have presented data concerning the expression of DOG1 in head and neck squamous cell carcinoma (HNSCC). The expression of DOG1 in HNSCC appears to be associated with a poor prognosis. The aim of this study was to analyze the expression pattern of DOG1 in poorly differentiated carcinoma of the upper aerodigestive tract. MATERIALS AND METHODS: A total of 84 specimens from 31 patients with carcinomas of the upper aerodigestive tract were immunohistochemically investigated for DOG1 expression. Inclusion criterion was poorly to undifferentiated carcinoma of the head and neck, but samples of the same resection site that exhibited moderate or well-differentiated squamous cell carcinoma were also enrolled. Immunoreactivity in carcinomas was estimated using a visual score (0: negative; 1: basally positive, 2: parabasally positive, 3: completely positive, 4: basally and parabasally positive). RESULTS: Fifteen out of 84 specimens were immunoreactive to antibody to DOG1 (17.8%). DOG1 immunoreactivity was restricted to eight patients (25.8%). However, DOG1 expression was considerably heterogeneous in tumours, with three (9.6%) cases showing a positive reaction in all samples. Basal and parabasal staining patterns (five specimens each) dominated. DISCUSSION: This study demonstrated expression of DOG1 to be restricted to some poorly differentiated carcinomas of the upper aerodigestive tract. Although the proportion of DOG1-positive carcinomas was moderate compared to results of previous studies on head and neck cancer tissues, DOG1 expression possibly indicates a subset of HNSCC. Further studies are necessary to investigate the heterogeneity and clinical relevance of DOG1 expression in HNSCC.

Altered tryptophan hydroxylase 2 expression in enteric serotonergic nerves in Hirschsprung's-associated enterocolitis.

AIM: To determine if expression of colonic tryptophan hydroxylase-2 (TPH2), a surrogate marker of neuronal 5-hydroxytryptamine, is altered in Hirschsprung's-associated enterocolitis. METHODS: Entire resected colonic specimens were collected at the time of pull-through operation in children with Hirschsprung's disease (HSCR, n = 12). Five of these patients had a history of pre-operative Hirschsprung's-associated enterocolitis (HAEC). Controls were collected at colostomy closure in children with anorectal malformation (n = 10). The distribution of expression of TPH2 was evaluated using immunofluorescence and confocal microscopy. Protein expression of TPH2 was quantified using western blot analysis in the deep smooth muscle layers. RESULTS: TPH2 was co-expressed in nitrergic and cholinergic ganglia in the myenteric and submucosal plexuses in ganglionic colon in HSCR and healthy controls. Co-expression was also seen in submucosal interstitial cells of Cajal and PDGFRα(+) cells. The density of TPH2 immuno-positive fibers decreased incrementally from ganglionic bowel to transition zone bowel to aganglionic bowel in the myenteric plexus. Expression of TPH2 was reduced in ganglionic bowel in those affected by pre-operative HAEC compared to those without HAEC and healthy controls. However, expression of TPH2 was similar or high compared to controls in the colons of children who had undergone diverting colostomy for medically refractory HAEC. CONCLUSION: Altered TPH2 expression in colonic serotonergic nerves of patients with HSCR complicated by HAEC may contribute to intestinal secretory and motor disturbances, including recurrent HAEC.

ClC-3 Expression and Its Association with Hyperglycemia Induced HT22 Hippocampal Neuronal Cell Apoptosis.

Although apoptosis plays an important role in the development of Diabetic Encephalopathy (DE), the underlying molecular mechanisms remain unclear. With respect to this, the present work aims to study the variation in chloride/proton exchanger ClC-3 expression and its association with HT22 hippocampal neuronal apoptosis under hyperglycemic condition in vitro. The cells were stimulated with added 0, 5, or 25 mM glucose or mannitol for up to 72 hours before assessing the rate of ClC-3 expression, cell viability, and apoptosis. In a consecutive experiment, cells received chloride channel blocker in addition to glucose. The rate of cellular death/apoptosis and viability was measured using Flow Cytometry and MTT assay, respectively. Changes in ClC-3 expression were assessed using immunofluorescence staining and western blot analysis. The results revealed a significant increase in cellular apoptosis and reduction in viability, associated with increased ClC-3 expression in high glucose group. Osmolarity had no role to play. Addition of chloride channel blocker completely abolished this effect. Thus we conclude that, with its increased expression, ClC-3 plays a major role in hyperglycemia induced hippocampal neuronal apoptosis. To strengthen our understanding of this aforesaid association, we conducted an extensive literature search which is presented in this paper.

The utility of CDX2, GATA3, and DOG1 in the diagnosis of testicular neoplasms: an immunohistochemical study of 109 cases.

We identified 109 testicular tumors, including pure and mixed germ cell tumors and sex cord-stromal tumors, and conducted immunohistochemical staining for CDX2, DOG1, and GATA3 to address the potential utility of these readily available and commonly used markers in the evaluation of testicular tumors. Their expression has not been previously thoroughly examined in testicular germ cell tumors. The distribution, percentage, and intensity of positivity were assessed. CDX2 was positive in all yolk sac tumors, 25% of choriocarcinomas, 9% of seminomas, and 4% of embryonal carcinomas (sensitivity for yolk sac tumor, 100%; specificity, 89% [teratomas excluded]). CDX2 also stained glandular components within teratomas and identified inconspicuous yolk sac tumor components in 3 cases previously diagnosed as pure embryonal carcinoma. GATA3 was positive in all choriocarcinomas (sensitivity, 100%). Weak GATA3 immunostaining was also seen in 12% of yolk sac tumors and 2 of 2 primitive neuroectodermal tumors. DOG1 was negative in all tumors, but stained spermatocytes and spermatids and the luminal borders of the epididymis and rete testis of nonneoplastic testis. We conclude that CDX2 is a sensitive and relatively specific marker for yolk sac tumor among the nonteratomatous germ cell tumors. It may serve to screen for yolk sac tumor components often overlooked on hematoxylin and eosin-stained slides. GATA3 is helpful in the recognition of trophoblastic cells, especially of intermediate type. DOG1 is a sensitive marker for spermatocytes and needs to be further studied for its significance.

Molecular identity of cardiac mitochondrial chloride intracellular channel proteins.

Emerging evidences demonstrate significance of chloride channels in cardiac function and cardioprotection from ischemia-reperfusion (IR) injury. Unlike mitochondrial potassium channels sensitive to calcium (BKCa) and ATP (KATP), molecular identity of majority of cardiac mitochondrial chloride channels located at the inner membrane is not known. In this study, we report the presence of unique dimorphic chloride intracellular channel (CLIC) proteins namely CLIC1, CLIC4 and CLIC5 as abundant CLICs in the rodent heart. Further, CLIC4, CLIC5, and an ortholog present in Drosophila (DmCLIC) localize to adult cardiac mitochondria. We found that CLIC4 is enriched in the outer mitochondrial membrane, whereas CLIC5 is present in the inner mitochondrial membrane. Also, CLIC5 plays a direct role in regulating mitochondrial reactive oxygen species (ROS) generation. Our study highlights that CLIC5 is localized to the cardiac mitochondria and directly modulates mitochondrial function.

A Role of TMEM16E Carrying a Scrambling Domain in Sperm Motility.

Transmembrane protein 16E (TMEM16E) belongs to the TMEM16 family of proteins that have 10 transmembrane regions and appears to localize intracellularly. Although TMEM16E mutations cause bone fragility and muscular dystrophy in humans, its biochemical function is unknown. In the TMEM16 family, TMEM16A and -16B serve as Ca(2+)-dependent Cl(-) channels, while TMEM16C, -16D, -16F, -16G, and -16J support Ca(2+)-dependent phospholipid scrambling. Here, we show that TMEM16E carries a segment composed of 35 amino acids homologous to the scrambling domain in TMEM16F. When the corresponding segment of TMEM16A was replaced by this 35-amino-acid segment of TMEM16E, the chimeric molecule localized to the plasma membrane and supported Ca(2+)-dependent scrambling. We next established TMEM16E-deficient mice, which appeared to have normal skeletal muscle. However, fertility was decreased in the males. We found that TMEM16E was expressed in germ cells in early spermatogenesis and thereafter and localized to sperm tail. TMEM16E(-/-) sperm showed no apparent defect in morphology, beating, mitochondrial function, capacitation, or binding to zona pellucida. However, they showed reduced motility and inefficient fertilization of cumulus-free but zona-intact eggs in vitro. Our results suggest that TMEM16E may function as a phospholipid scramblase at inner membranes and that its defect affects sperm motility.

Expression of SOX10 in Salivary Gland Oncocytic Neoplasms: A Review and a Comparative Analysis with Other Immunohistochemical Markers.

OBJECTIVES: We evaluated SOX10 (SRY-related HMG-box 10) in differentiating acinic cell carcinoma (AciCC) from other salivary gland neoplasms with oncocytic features on fine-needle aspiration cell blocks (FNA CB) and compared its performance to DOG1 (discovered on gastrointestinal stromal tumor 1). MATERIAL AND METHODS: 35 FNA CB of oncocytic salivary gland neoplasms, i.e. 13 cases of AciCC, 16 of Warthin tumor (WT), 3 of mucoepidermoid carcinoma (MEC) and 3 of oncocytoma (ONC), and 75 salivary gland resections, i.e. 26 AciCC, 7 WT, 36 MEC, 3 ONC, 2 mammary analog secretory carcinomas (MASC) and 1 papillary cystadenoma were stained for SOX10 and DOG1. RESULTS: None of the benign oncocytic neoplasms were immunoreactive for SOX10 on CB or resection, similar to DOG1. On CB, 61.5 and 77% of AciCC were positive for SOX10 and DOG1, respectively. All surgically resected AciCC cases were positive for SOX10 and DOG1; other malignant oncocytic lesions such as MEC and MASC demonstrated variable SOX10 and DOG1 staining. CONCLUSION: The use of SOX10 may increase the diagnostic accuracy of oncocytic lesions on FNA. In this context, SOX10 is equivalent to DOG1 in ruling out benign lesions such as WT and ONC; however, negative results for SOX10 as well as DOG1 do not favor a benign diagnosis since MEC is often negative for both markers.