Morphological changes in intraepithelial and stromal telocytes in Cyprinus carpio in response to salinity stress.

Telocytes establish connections and communicate with various types of cells and structures. Few experimental studies have been performed on telocytes. In this study, we investigated the effect of salinity stress on telocytes in relation to osmoregulatory, immune, and stem cells. After exposing the common carp to 0.2 (control), 6, 10, or 14 ppt salinity, we extracted and fixed gill samples in glutaraldehyde, processed and embedded the samples in resin, and prepared semi-thin and ultrathin sections. Two types of telocytes were identified: intraepithelial and stromal telocytes. Intraepithelial telocytes were found to form part of the cellular lining of the lymphatic space and shed secretory vesicles into this space. Stromal telocytes were observed to shed their secretory vesicles into the secondary circulatory vessels. Both intraepithelial and stromal telocytes were enlarged and exhibited increased secretory activities as salinity increased. They exerted their effects via direct contact and paracrine signaling. The following changes were observed in samples from fish exposed to high salinity levels: chloride cells underwent hypertrophy, and their mitochondria became cigar-shaped; pavement cells were enlarged, and their micro-ridges became thin and elongated; stromal telocytes established contact with stem cells and skeletal myoblasts; skeletal muscle cells underwent hypertrophy; and macrophages and rodlet cells increased in number. In conclusion, our findings indicate that intraepithelial and stromal telocytes respond to salinity stress by activating cellular signaling and that they play major roles in osmoregulation, immunity, and regeneration.

Gastroprotective effect of low dose Eugenol in experimental rats against ethanol induced toxicity: Involvement of antiinflammatory and antioxidant mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Syzygium aromaticum L. volatile oil (clove oil) has been traditionally used for various stomach disorders including inflammatory conditions. Eugenol is the major constituent present in the volatile oil, and it has been established as a gastroprotective agent through many published studies, but the exact and complete mechanism of ulcer protection is not delineated yet. Moreover, it plays precisely the opposite effect in higher dose in antiulcer properties with worsening the ulcer at a higher dose. AIM: This study aims to carry out the prophylactic cytoprotective effect of eugenol with single low doses and explore the probable interrelated underlying transcriptional and translational level mechanism of cytoprotection such as antioxidative, anti-inflammatory, mucous generation in rats using ethanol-induced ulcer model. METHODS: Rats were administered with different doses of eugenol before ethanol intragastrically. The effects of the eugenol on mucous production, Nitric oxide generation, PGE2 synthesis, lipid peroxidation were recorded together with cytokines measurement in the blood. TNF-α and IL-6, two key cytokines, were also studied in specific. In addition, studies on the immunohistochemical and gene expression of HSP70 and iNOS indicators have been conducted. RESULTS: According to our findings, Eugenol substantially reduced the ulcer index and completely protected the mucosa from lesions. By restoring the lowered GSH and NP-SH levels, the protective effect of the eugenol was found to be augmented at both doses. This finding has corresponded to an increase in MDA, which was lowered by ethanol administration. Pre-treatment with eugenol on the ethanol-induced ulcer reduced the plasma NO levels and increased PGE2 along with a decreased TNF-α and IL-6 concentration. Additionally, significant transcriptional and translational upregulation of HSP70 and downregulation of iNOS were detected in the eugenol-treated rat stomach tissue. CONCLUSION: Our findings demonstrated that eugenol had a considerable gastroprotective impact at low doses, which could be attributed to its ability to regulate inflammatory reactions and antioxidant capacity.

Endocrine, Stemness, Proliferative, and Proteolytic Properties of Alarm Cells in Ruby-Red-Fin Shark (Rainbow Shark), Epalzeorhynchos frenatum (Teleostei: Cyprinidae).

The current study investigated the morphological, histochemical, and immunohistochemical characteristics of alarm cells and their precursors in ruby-red-fin shark (rainbow shark), Epalzeorhynchos frenatum (Teleostei: Cyprinidae). Precursor alarm cells were shown to be small, cuboidal, pyramidal, or round in shape, with eosinophilic cytoplasm, resting on the basement membrane of the epidermis. The cells later elongated to become columnar in shape. Subsequently, they enlarged and became large oval-shaped cells. They then underwent shrinkage and vacuolation. The superficial alarm cells were collapsed. Alarm cells were found to have an affinity for different histochemical stains, including bromophenol blue, iron hematoxylin, Sudan black, Mallory triple trichrome, Crossman's trichrome, Safranin O, and Weigert's stains, as well as lipase and alkaline phosphatase. Endocrine properties of the alarm cells were identified by silver staining and synaptophysin immunostaining. Alarm cells exhibited stemness activities and had a strong immunoaffinity for CD117. They had a proteolytic function, as identified by lysosome-specific staining with acridine orange and strong immunoaffinity for matrix metalloproteinase (MMP-9). They also exhibited proliferatively, reflected by immunological staining by proliferating cell nuclear antigen. In conclusion, alarm cells are unique epidermal cells with multiple functions. They play immunological, and endocrine, roles. They also retain stemness and proliferative properties.

Unraveling the Catha edulis Extract Effects on the Cellular and Molecular Signaling in SKOV3 Cells.

Khat (Catha edulis (Vahl) Endl.) is an evergreen flowering shrub used as a stimulant in many regions worldwide including East Africa, the Arabian Peninsula, Europe, and the United States. Chewing leaves of khat induces excitement and euphoria, which are primarily attributed to two major constituents, cathinone and cathine. Khat also contains other important constituents such as cathedulins. A considerable number of studies reported side effects induced by the khat extracts to both embryos and adults. These include teratogenicity and developmental retardation, oral cancer and ulcers, high blood pressure, and myocardial infarction. So far, little attention has been paid to the effects of khat extracts on the molecular signaling interactions. We aimed in this study to investigate this through evaluating the effects of khat extracts on SKOV3, a human ovarian adenocarcinoma cell line. We show, by in vitro assays, that khat induces several cellular defects including reduced cell size, cell membrane damage, and apoptosis. At high khat extract concentrations, the cell metabolic activity, cell cycle, and cellular proliferation were affected. RT-qPCR analysis showed an increase in the gene expression of the apoptotic marker BAX, the tumor suppressor p53, and the inflammatory cytokine IL-6. Protein expression analysis by immunostaining showed downregulation of ß-catenin, E-cadherin, and Ki-67 and upregulation of FZD8 and SPRY2, suggesting that Wnt and FGF signaling were implicated. SwissTargetPrediction in silico analysis showed that khat constituents cathine, cathinone, catheduline K2, and catheduline E5 bind to family A G-protein-coupled receptor, cause many neurological diseases and disorders such as Alzheimer's, schizophrenia, depression, and anxiety, and induce many ovarian cancer-related diseases. The analysis also showed that important signaling pathways such as CREB, Wnt, FGF, IL-6, and ERK/MAPK, and that of the endometrial cancer, and cell cycle were implicated. Upstream regulators of cathine and cathinone were found to potentially target several molecules including interleukin-8, MMP2, PLAU, and micro-RNAs. In conclusion, khat induces significant cellular and molecular changes that could potentially cause a wide range of serious diseases and syndromes. Such an impact could have a heavy burden on the health care system in the countries where khat is consumed.

Effect of Khat (Catha edulis Forsk) extract on testicular maturation in pre-pubertal and pubertal rats: A morphological and biochemical study.

The present study aimed at analysing the effect of Khat plant extract on rat testicular development. Thirty-two weaned male albino rats (4 weeks old) were divided into four groups consisting of eight animals each. While control animals received normal saline, rats of groups I, II and III received 100, 200 and 300 mg Khat extract per kg body weight dissolved in distilled water by oral gavage daily for 8 weeks, respectively. Blood samples were collected in separate heparinized tubes by cardiac puncture from each rat and processed for measuring plasma levels of reproductive hormones LH, FSH, testosterone and prolactin. Five-µm sections were stained with haematoxylin and eosin and examined by light microscope. Some sections were immunostained for protamine-1 representing a biomarker for intact sperm differentiation. The present study clearly demonstrated that Khat extract has a pronounced effect on testicular maturation of developing albino rats at both the morphological and functional levels. Khat-treated groups revealed a significantly low serum testosterone level and severe impairment of spermatogenesis when compared with control animals. The current findings also verified, for the first time, that the final stages of sperm maturation (spermiogenesis) were strongly impaired after administration of Khat extract to experimental rats particularly at a higher dose (300 mg/kg body weight). This was proved by the very weak, if any, expression of protamine-1 in the maturing spermatids in Khat-treated rats.

Migratory Activities and Stemness Properties of Rodlet Cells.

The current study aimed to characterize different stages of rodlet cells using light microscopy, immunohistochemistry, and transmission electron microscopy. Granular rodlet cells have a distinct granular cytoplasm. Transitional rodlet cells had distinct capsules, and immature granules. Mature rodlet cells were pear-shaped and had elongated granules. Ruptured rodlet cells had a granular cytoplasm. The affinity of rodlet cells for different histochemical techniques was detected. Immunohistochemical analysis of rodlet cells for stem cell markers such as CD117, CD34, proliferation marker, proliferating cell nuclear antigen (PCNA), endopeptidase activity; matrix metalloproteinase-9 (MPP-9) and the angiogenic factor; vascular endothelial growth factor (VEGF) was investigated. All stages of rodlet cells were expressed CD117. However, the ruptured stage was CD117-negative. The granular, transitional, and mature stages had strong CD34 immunoaffinity, while the ruptured rodlet cells were CD34-negative. The most potent immunoreactivity for PCNA was the granular rodlet cells. The transitional cells exhibited less immunoreactivity, while mature rodlet cells had no immunoaffinity for PCNA. All stages of rodlet cells had high enzyme activity as indicated by Acridine orange and exhibited strong MPP-9 immunoaffinity. VEGF is mostly expressed by granular, transitional, and mature rodlet cells. In conclusion, rodlet cells relatively had stemness properties, endopeptidase activity, express a proliferation marker, and angiogenic factors. We suggest a potential role of rodlet cells in immune defense.

Morphological and immunohistochemical phenotype of TCs in the intestinal bulb of Grass carp and their potential role in intestinal immunity.

The current study investigated telocytes (TCs) in the intestinal bulb of Grass carp using light microscopy (LM), Transmission electron microscopy (TEM), scanning electron microscopy, and immunohistochemistry (IHC). By LM, TCs were distinguished by the typical morphological features that had a cell body and telopodes using HE, toluidine blue, methylene blue, Marsland silver stain, Grimelius's silver nitrate, Giemsa, PAS, combined AB pH2,5/PAS, Crossmon's and Mallory triple trichrome, Van Gieson stains, Verhoeff's stain, Sudan black, osmic acid, performic acid with methylene blue and bromophenol blue. TCs were identified under the epithelium as an individual cell or formed a TCs sheath. They detected in the lamina propria, between muscle fibers, around the myenteric plexus and fibrous tissue. TCs acquired immunological features of endocrine cells that exhibited high affinity for silver stain, performic acid with methylene blue, Marsland stain, and immunohistochemical staining using chromogranin A. Sub epithelial TCs were closely related to the endocrine cells. TCs and their secretory activities were recognized using acridine orange. TCs were identified by IHC using CD34, CD117, S100-protein, desmin. TCs formed a3D network that established contact with macrophage, mast cells, dendritic cells, lymphocytes, smooth muscle fibers, fibroblast, Schwann cells and nerve fibers. In conclusion, the localization of TCs in relation to different types of immune cells indicated their potential role in the maintenance of intestinal immunity.

Ameliorative effect of Boesenbergin A, a chalcone isolated from Boesenbergia rotunda (Fingerroot) on oxidative stress and inflammation in ethanol-induced gastric ulcer in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Boesenbergia rotunda (L.) Mansf. Kulturpfl., previously known as Boesenbergia pandurata (Family: Zingiberaceae) is a ginger species, locally known as fingerroot. It is an integral part of Southeast Asian traditional medicine in alleviating many gastrointestinal disorders such as flatulence, carminative, stomach ache, dyspepsia, and peptic ulcer. AIM OF THE STUDY: Earlier we have investigated the cytoprotective effect of Boesenbergia rotunda extract. In the present study, we investigated the gastroprotection activity of Boesenbergin A (BA), a chalcone isolated from Boesenbergia rotunda extract in ethanol-induced ulcer model in rats. Besides, the contribution of anti-inflammatory and anti-oxidant ability of BA as probable mechanisms involved in the anti-ulcer activity, also been studied. MATERIALS AND METHODS: BA was orally administered in rats before ulcer induction with ethanol. The lesions of the gastric mucosa were evaluated macroscopically and histopathologically. The efficiency of BA in mucus production, NO production, PGE2 synthesis, mucosal nonprotein sulphydryls, glutathione (GSH) level, and lipid peroxidation (MDA) level were studied. The involvement of the anti-inflammatory capacity of BA was analyzed by using the measurement of cytokines such as TNF-α and IL-6. Finally, the expression of biomarkers such as HSP 70 and iNOS was analyzed at the transcriptional and translational levels. RESULTS: We confirmed the protective capacity of BA via the reduction of ulcerated and haemorrhagic areas. It has induced the protection through lowering GSH, MDA and increased NP-SH level. The plasma NO levels were significantly less in BA treated rats. Both cytokines TNF-α and IL-6 were decreased together with elevated PGE2. Upregulation of HSP and downregulation of iNOS were determined in immunohistochemical and gene expression studies CONCLUSIONS: The current results suggest that the prophylactic effect found with BA is due to (i) boosting of gastric mucus production and suppression of inflammatory mediators, via pro-inflammatory cytokines and (ii) modulating the oxidative stress response. The usefulness of Boesenbergia rotunda in folk medicine in treating ulcers partially could be due to the presence of this chalcone.

Girinimbine from curry leaves promotes gastro protection against ethanol induced peptic ulcers and improves healing via regulation of anti-inflammatory and antioxidant mechanisms.

Curry leaves (Murraya koenigii) are a leafy spice used in Indian cookery for its fragrant aroma. Many bioactive functional compounds have been identified, and among them carbazole alkaloids have attracted wide attention due to their multi-dimensional medicinal value. Even though it has been established that the carbazole alkaloid is responsible for the anti-ulcer effect showed by this culinary herb, there is no further evidence to say which phytochemical is responsible for this. In the present study, we investigated the gastro-protective effects and mechanism of girinimbine, a major carbazole alkaloid present in curry leaves. Rats were administered with ethanol to produce gastric ulcers, and the prophylactic effect of girinimbine was evaluated. A macroscopic and histological examination was carried out to examine the lesions. Furthermore, the mucus production, NO production, PGE2 synthesis, mucosal nonprotein sulphydryls, glutathione (GSH) level, lipid peroxidation (MDA) level and COX inhibition were assessed. In addition, in particular, TNF-α and IL-6, two important cytokines, were evaluated. Immunohistochemical and gene expression studies were conducted to determine the HSP70 and iNOS biomarkers. Our results indicated that girinimbine significantly reduced the ulcer index and totally safeguarded the mucosa from lesions. The protective effect of girinimbine was complemented through the restoration of the reduced GSH and NP-SH level. This was associated with a reduction of MDA, which was elevated by the administration of ethanol. Pre-treatment of the ethanol induced ulcer with girinimbine reduced the NO concentration in the plasma and elevated PGE2 together with a decreased level of TNF-α and IL-6. Girinimbine had shown suppressing effects on COX-2 enzymes, but not on COX-1. In addition, significantly upregulated HSP70 and downregulated iNOS were observed in girinimbine treated rat tissue at both the transcriptional and translational level. Our results clearly indicated that girinimbine displayed a significant gastro-protection effect, via the capacity to inhibit inflammatory responses and antioxidant potential.

Impact of Ginkgo biloba extract and magnetized water on the survival rate and functional capabilities of pancreatic ß-cells in type 2 diabetic rat model.

INTRODUCTION: Type 2 diabetes (T2D) is a widely distributed disease that affects large population worldwide. This study aimed to verify the role of Ginkgo biloba (GB) extract and magnetized water (MW) on the survival rate and functional capabilities of pancreatic ß-cells in type 2 diabetic rats. MATERIALS AND METHODS: T2D was induced by feeding the rats on a high-fat diet (20% fat, 45% carbohydrate, 22% protein) for eight weeks followed by intra-peritoneal injection of a single low dose of streptozotocin (25mg/Kg). Forty rats were randomly assigned to four groups (n=10 rats) as follows: non treated control and three diabetic groups. One diabetic group served as a positive control (diabetic), while the other two groups were orally administered with water extract of GB leaves (0.11 g/kg/day) and MW (600 gauss) for four weeks, respectively. RESULTS: The ß-cell mass and insulin expression in these cells increased markedly after both treatments, particularly in GB treated group. In addition, the immune-expression of the two antioxidant enzymes; glutathione and superoxide dismutase 2 (SOD2) in the pancreatic tissue demonstrated a down-regulation in GB and MW treated groups as compared with the diabetic group. CONCLUSION: A four-week treatment of GB and MW protected pancreatic ß-cell cells and improved their insulin expression and antioxidant status in type 2 diabetic rats.

Immunohistochemical localization of progesterone receptors alpha (PRA) in ovary of the pseudopregnant rabbit.

Progesterone plays an important role in the reproductive function and follicular development in mammals. The aim of the present study was to examine the localization of progesterone receptor alpha (PRA) in ovary of pseudopregnant rabbit by immunohistochemical methods. Samples were collected from 14 h. to 18 days of pseudopregnancy. At the first stage of pseudopregnancy (14 h.), the rabbit ovary showed moderate immunostaining of PRA in the granulosa cells and theca interna cells of preovulatory follicle and in the stroma cells. At the middle stage of pseudopregnancy (3-7 days), the rabbit ovary showed strong immunostaining of PRA in ovarian surface epithelial cells, follicular cells of the primary follicle, granulosa cells and theca interna cells of the growing and antral follicles. Moderate immunoexpression of PRA were observed in the large lutein cells and endothelial cells of the corpus haemorrhagicum and corpus luteum and in the stroma cells. At the end of pseudopregnancy (18 days) strong PRA reactions were detected in the small lutein cells of the regressed corpus luteum. Moderate to strong PRA immuno-expression were observed in the proliferated theca interna cells of the atretic antral follicles. The atretic large lutein cells of the regressed corpus luteum showed negative immunostaining for PRA. This study showed that the PRA positive small lutein cells of the regressed corpus luteum and the PRA positive proliferated theca interna cells of the atretic antral follicles were transformed into PRA positive interstitial gland cells. In conclusion, the present study had described the distribution of PRA in the ovary of pseudopregnant rabbit, which is not discussed before in the available literature. It also gives more information about follicular dynamic, formation and origin of interstitial glands, mechanism of ovulation, formation and regression of the corpus luteum.

Catha edulis forsk mediates embryotoxic effects in rats: an experimental study / Catha edulis forsk modera los efectos embriotóxicos en ratas: un estudio experimental

Catha edulis Forsk leaves (Khat) is a flowering plant. A high proportion of the adult population in the Arabian Peninsula and the Horn of Africa chews it for its mild stimulant effect. The aim of the current study was to investigate the embryotoxic and teratogenic effects of the Khat extract using 60 female pregnant rats. These were divided to a Khat extract-treated group and a control group. Methanolic extract of Khat was orally given to the treated group 4 days before mating and up to day 16 of pregnancy with a dose of 100 mg/kg. Our results showed that significant number of embryos of the Khat-treated mothers were malformed and different in size and shape compared to embryos from the mothers of the control group. At day 8 of pregnancy, malformed embryos had ill developed primitive layers. By day 10 of pregnancy, neural tube and the somite were not formed compared to the control embryos. At later stages of pregnancy, embryos of the Khat-treated mothers appeared severely abnormal with opened neural groove and visceral pouches. Disrupted normal neural tube development, undifferentiated brain vesicles, incomplete closure of the brain flexures were also observed in these embryos. Highly significant increase in the number of the resorbed embryos of the Khat-treated mothers were observed (P < 0.01). The resorbed embryos appeared as a cellular collection in their placenta with some of their decidua had no visible embryonic tissues. In conclusions, Khat induced embryotoxic effects as well as severely affected the early normal embryonic development in rat.

Catha edulis (Khat) es una planta floreciente. Una alta proporción de la población adulta en la Península Arábiga y el Cuerno de África la mastica por su efecto estimulante. El objetivo del presente estudio fue investigar los efectos embriotóxicos y teratogénicos del extracto de Khat utilizando 60 ratas hembras preñadas. Estas se dividieron en un grupo tratado con extracto de Khat y un grupo control. El extracto metanólico de Khat se administró por vía oral al grupo tratado 4 días antes del apareamiento y hasta el día 16 de preñez con una dosis de 100 mg / kg. Los resultados mostraron que una cantidad significativa de embriones de las madres tratadas con Khat tenían malformaciones y eran diferentes en tamaño y forma en comparación con los embriones de las madres del grupo control. En el día 8 de preñez, los embriones malformados tenían capas primitivas mal desarrolladas. Para el día 10 de preñez, el tubo neural y el somito no se formaron en comparación con los embriones del grupo control. En etapas posteriores de la preñez, los embriones de las madres tratadas con Khat parecían severamente anormales con surcos neurales abiertos y bolsas viscerales. También se observaron alteraciones en el desarrollo normal del tubo neural, vesículas cerebrales indiferenciadas y el cierre incompleto de las flexiones cerebrales en estos embriones. Se observó un aumento altamente significativo en el número de embriones reabsorbidos de las madres tratadas con Khat (P <0,01). Los embriones reabsorbidos aparecieron como una colección celular en su placenta con algunas de sus deciduas sin tejidos embrionarios visibles. Khat indujo efectos embriotóxicos y afectó severamente el desarrollo embrionario normal temprano en la rata.

Antidiabetic and Antioxidant Impacts of Desert Date (Balanites aegyptiaca) and Parsley (Petroselinum sativum) Aqueous Extracts: Lessons from Experimental Rats.

Medicinal plants are effective in controlling plasma glucose level with minimal side effects and are commonly used in developing countries as an alternative therapy for the treatment of type 1 diabetes mellitus. The aim of this study is to evaluate the potential antidiabetic and antioxidant impacts of Balanites aegyptiaca and Petroselinum sativum extracts on streptozotocin-induced diabetic and normal rats. The influences of these extracts on body weight, plasma glucose, insulin, total antioxidant capacity (TAC), malondialdehyde (MDA) levels, and liver-pyruvate kinase (L-PK) levels were assessed. Furthermore, the weight and histomorphological changes of the pancreas were studied in the different experimental groups. The herbal preparations significantly reduced the mean plasma glucose and MDA levels and significantly increased the mean plasma insulin, L-PK, and TAC levels in the treated diabetic groups compared to the diabetic control group. An obvious increase in the weight of the pancreas and the size of the islets of Langerhans and improvement in the histoarchitecture were evident in the treated groups compared to untreated ones. In conclusion, the present study provides a scientific evidence for the traditional use of these extracts as antidiabetic and antioxidant agents in type 1 diabetes mellitus.

Klhl31 attenuates ß-catenin dependent Wnt signaling and regulates embryo myogenesis.

Klhl31 is a member of the Kelch-like family in vertebrates, which are characterized by an amino-terminal broad complex tram-track, bric-a-brac/poxvirus and zinc finger (BTB/POZ) domain, carboxy-terminal Kelch repeats and a central linker region (Back domain). In developing somites Klhl31 is highly expressed in the myotome downstream of myogenic regulators (MRF), and it remains expressed in differentiated skeletal muscle. In vivo gain- and loss-of-function approaches in chick embryos reveal a role of Klhl31 in skeletal myogenesis. Targeted mis-expression of Klhl31 led to a reduced size of dermomyotome and myotome as indicated by detection of relevant myogenic markers, Pax3, Myf5, myogenin and myosin heavy chain (MF20). The knock-down of Klhl31 in developing somites, using antisense morpholinos (MO), led to an expansion of Pax3, Myf5, MyoD and myogenin expression domains and an increase in the number of mitotic cells in the dermomyotome and myotome. The mechanism underlying this phenotype was examined using complementary approaches, which show that Klhl31 interferes with ß-catenin dependent Wnt signaling. Klhl31 reduced the Wnt-mediated activation of a luciferase reporter in cultured cells. Furthermore, Klhl31 attenuated secondary axis formation in Xenopus embryos in response to Wnt1 or ß-catenin. Klhl31 mis-expression in the developing neural tube affected its dorso-ventral patterning and led to reduced dermomyotome and myotome size. Co-transfection of a Wnt3a expression vector with Klhl31 in somites or in the neural tube rescued the phenotype and restored the size of dermomyotome and myotome. Thus, Klhl31 is a novel modulator of canonical Wnt signaling, important for vertebrate myogenesis. We propose that Klhl31 acts in the myotome to support cell cycle withdrawal and differentiation.

Klhl31 is associated with skeletal myogenesis and its expression is regulated by myogenic signals and Myf-5.

Klhl31 is an orthologue of Drosophila Kelch and belongs to a family of Kelch-like proteins in vertebrates. Members of this family contain multiple protein domains, including an amino-terminal broad complex/tram-track/bric-a-brac (BTB) or poxvirus and zinc finger (POZ) domain, carboxy-terminal Kelch repeats and a central linker region. We show that Klhl31 is highly expressed in the developing heart, the somite myotome and later in differentiated skeletal muscle and the myocardium. In developing somites expression of Klhl31 was initiated in the epaxial domain of the myotome, shortly after the skeletal muscle specific bHLH transcription factor, MyoD, was first expressed. Klhl31 remained expressed in skeletal muscle throughout embryonic and fetal development. Tissue ablations and rescue experiments that regulate myogenesis also govern expression of Klhl31 expression in somites. In particular, axial tissues, neural tube, floor plate and notochord, and surface ectoderm, provide combinatorial cues for myogenesis and the appropriate expression of Klhl31. We show that a combination of myogenic signals, Shh and either Wnt-1 or Wnt-6, are sufficient for Klhl31 expression in the dorsal somite. Furthermore, ectopic expression of Myf-5 led to expression of Klhl31 in the developing neural tube, indicating that Klhl31 is a novel and integral part of vertebrate myogenesis.