Implications of endoplasmic reticulum stress and beta-cell loss in immunodeficient diabetic NRG-Akita mice for understanding monogenic diabetes.

BACKGROUND: Immunodeficient mice models have become increasingly important as in vivo models engrafted with human cells or tissues for research. The NOD-Rag1null Ins2Akita Il2rnull (NRG Akita) mice is a model combined with immunodeficient NRG and monogenic diabetes Akita mice that develop spontaneous hyperglycemia with progressive loss of pancreatic insulin-producing beta-cells with age. This model is one of the monogenic diabetic models, which has been providing a powerful platform for transplantation experiments of stem cells-generated human ß-cells. This research aimed to provide insights into the mechanisms underlying this monogenic diabetes, which remains incompletely understood. METHODS: Histological and immunofluorescence analyses were conducted on endocrine pancreatic islets to compare NRG wild-type (Wt) controls with NRG-Akita mice. Our investigation focused on assessing the expression of endocrine hormones, transcription factors, proliferation, ER stress, and apoptosis. RESULTS: Histological analyses on NRG-Akita mice revealed smaller islets at 6-weeks-old, due to fewer ß-cells in the islets, compared to NRG-Wt controls, which further progressed with age. The proliferation rate decreased, and apoptosis was abundant in ß-cells in NRG Akita mice. Interestingly, our mechanistic analyses revealed that ß-cells in NRG-Akita mice progressively accumulated the endoplasmic reticulum (ER) stresses, leading to a decreased expression of pivotal ß-cell transcriptional factor PDX1. CONCLUSIONS: Altogether, our mechanistic insight into ß-cell loss in this model could shed light on essential links between ER stress, proliferation, and cell identity, which might open the door to new therapeutic strategies for various diseases since ER stress is one of the most common features not only in diabetes but also in other degenerative diseases.

Thoracic cavity of the Shirazi cats: New insights using computed tomography and magnetic resonance imaging.

Our study provided a comprehensive characterization of the thorax of Shirazi cats by comparing the relevant soft and bone windows of computed tomography (CT) and magnetic resonance imaging (MRI) with cross, sagittal and coronal sectional anatomy. We outlined the mediastinum and its anatomic relationships with the trachea, oesophagus, lungs, heart, cranial and caudal vena cavae, and other thoracic structures using the data series gathered from adult normal Shirazi cats. The cranial mediastinum extended from the thoracic inlet to the 4th intercostal space, the middle mediastinum extended from the 5th and 7th intercostal spaces and was occupied by the heart and large blood vessels and the caudal mediastinum extended as a short and narrow portion from the 8th intercostal space to the diaphragm. The contents of the mediastinum and its relationship with the lungs and diaphragm were clearly presented in coronal-sectional anatomy and CT slices. The diaphragm was clearly observed in the lung windows of the ventral thorax. Sagittal-sectional anatomy and CT clarified the thorax's architecture and its contents, with higher density in the soft windows. The distribution of thoracic vessels on cross- and coronal-contrast CT scans was clearly visible. In addition, MRI scans provided an excellent anatomic reference of the thorax with the help of cross, coronal and sagittal scans, especially in the heart and blood vessels. Our study provides a valuable atlas for the diagnosis of malformations of the thoracic structures and offers better assessments for helping veterinary radiologists and clinicians in diagnostic processes.

Fate mapping of Trps1 daughter cells during cardiac development using novel Trps1-Cre mice.

Tricho-rhino-phalangeal syndrome (TRPS) is a rare congenital disorder that is characterized by abnormal hair growth and skeletal deformities. These result in sparse hair, short stature, and early onset of joint problems. Recent reports have shown that a relatively high proportion of patients with TRPS exhibit a broad range of congenital heart defects. To determine the regulation of Trps1 transcription in vivo, we generated novel transgenic mice, which expressed Cre recombinase under the murine Trps1 proximal promoter sequence (Trps1-Cre). We crossed these mice with Cre reporter mice to identify Trps1 daughter cells. Labeled cells were observed in the appendicular joint tissue, dermal papilla of the hair follicles, cardiac valves, aortic sinus, atrial walls, and the interventricular septum. In situ analysis showed restricted Trps1 expression, which was observed in endocardial cushions of the outflow tract, and in leaflets of all mature cardiac valves. These results suggest that the Trps1 proximal promoter sequence contains some of the tissue-specific Trps1 regulatory region. Further, our findings partially explain why patients with TRPS show a broad range of congenital cardiac defects, although Trps1 expression is observed in a more restricted fashion. genesis 54:379-388, 2016. © 2016 Wiley Periodicals, Inc.

Ontogeny and innervation of taste buds in mouse palatal gustatory epithelium.

We investigated the relationship between mouse taste bud development and innervation of the soft palate. We employed scanning electron microscopy and immunohistochemistry using antibodies against protein gene product 9.5 and peripherin to detect sensory nerves, and cytokeratin 8 and α-gustducin to stain palatal taste buds. At E14, nerve fibers were observed along the medial border of the palatal shelves that tracked toward the epithelium. At E15.5, primordial stages of taste buds in the basal lamina of the soft palate first appeared. At E16, the taste buds became large spherical masses of columnar cells scattered in the soft palate basal lamina. At E17, the morphology and also the location of taste buds changed. At E18-19, some taste buds acquired a more elongated shape with a short neck, extending a variable distance from the soft palate basal lamina toward the surface epithelium. At E18, mature taste buds with taste pores and perigemmal nerve fibers were observed on the surface epithelium of the soft palate. The expression of α-gustducin was demonstrated at postnatal day 1 and the number of pored taste buds increased with age and they became pear-shaped at 8 weeks. The percent of pored fungiform-like papillae at birth was 58.3% of the whole palate; this increased to 83.8% at postnatal day 8 and reached a maximum of 95.7% at 12 weeks. The innervation of the soft palate was classified into three types of plexuses in relation to taste buds: basal nerve plexus, intragemmal and perigemmal nerve fibers. This study reveals that the nerve fibers preceded the development of taste buds in the palate of mice, and therefore the nerve fibers have roles in the initial induction of taste buds in the soft palate.

Equine anatomedia: development, integration and evaluation of an e-learning resource in applied veterinary anatomy / Anatomedia equina: desarrollo, integración y evaluación de un recurso e-learning en anatomía veterinaria aplicada

In Egypt, there is a growing movement to encourage veterinary student-centered learning using the most up to date educational technologies. This paper focuses on a computer-facilitated learning program "Equine Anatomedia", which comprises now two modules (head and digit) fully integrated with the applied anatomy curriculum at Alexandria and Damanhour Universities. The educational design of this program allows students and clinicians to explore anatomical concepts, principles and procedure guidelines in a manner more suited to their individual learning needs than traditional methods. The program comprises over 300 high quality images and diagrams, audio and video clips as well as animated graphics with colored keys highlighting the anatomical features. Staff and student feedback indicates that Equine Anatomedia is an effective and engaging learning tool which helps students to develop their knowledge in anatomy and to appreciate its relevance in clinical situations. In addition, it encourages student-staff interaction and is a useful tool in overcoming the challenges of limited resources and increasing numbers of students.

En Egipto, hay un movimiento creciente para fomentar el aprendizaje centrado en el estudiante de veterinaria utilizando las más modernas tecnologías educativas existentes a la fecha. Este trabajo se centra en un programa de aprendizaje por computación denominado "Anatomedia de Equinos", que en la actualidad está conformado de dos módulos (cabeza y dedos) totalmente integrados con el plan de estudios de la asignatura Anatomía Aplicada en las Universidades de Alejandría y Damanhour, Egipto. El diseño educativo de este programa permite a los estudiantes y los médicos clínicos explorar los conceptos anatómicos, como así también principios y directrices de procedimiento relacionados a sus necesidades individuales de aprendizaje, de una manera más adecuada que los métodos tradicionales de aprendizaje. El programa cuenta con más de 300 imágenes de alta calidad y diagramas, audios y vídeos, así como gráficos animados con identificaciones de colores que destacan las características anatómicas. La retroalimentación del personal a cargo del programa y de parte de los estudiantes indica que Anatomedia de Equinos es una herramienta de aprendizaje eficaz y atractiva que ayuda a los estudiantes a desarrollar sus conocimientos en anatomía y les permite apreciar su importancia en situaciones clínicas. Además, el programa permite fomentar la interacción alumno-personal y constituye una herramienta útil que ayuda a superar los retos que ocasionan los recursos limitados y el número creciente de estudiantes.

Morphological variations of the vallate papillae in some mammalian species.

The morpho-structural characteristics of the vallate papillae of the tongue of rat, dog, donkey and buffalo were investigated by macroscopy and their microstructure by light and scanning electron microscopy (SEM). The numbers of vallate papillae varied among the different species. In rat, a single vallate papilla surrounded by incomplete groove and an annular fold was observed. Taste buds were detected along the entire length of the medial and lateral groove epithelium, but not in the papillary dome. In dog, some papillae lacking the annular pad had irregular ridges and grooves toward the center of the papillary surface, while other papillae had small secondary papillary grooves arising from the center of the papilla. Taste buds were located in the medial and lateral epithelium of both primary and secondary grooves as well as in the dome epithelium. In donkey, two papillae were frequently observed around the midline of the tongue root, and an additional papilla was found occasionally in the middle and associated with secondary papilla. In buffalo, several papillae were relatively small and variable in shape. With SEM, small ridges and grooves were found in the papillae of donkey and buffalo. In both species, taste buds were constantly observed along the medial wall epithelium, but no taste buds were found in the lateral wall. We conclude that the vallate papillae exhibited peculiar characteristics, which are species specific and might have a correlation with the variable feeding habits among these animals.

Localization of Ulex europaeus agglutinin-I (UEA-I) in the developing gustatory epithelium of the rat.

To understand the development of the gustatory structures necessitates a reliable marker for both immature and mature taste buds. It has been reported that the intragemmal cells within the taste buds of adult rats were bound to Ulex europaeus agglutinin-I (UEA-I), a specific lectin for alpha-linked fucose, but it has not been determined whether immature taste buds, i.e. taste buds without an apparent taste pore, are labeled with UEA-I. The present study was conducted to examine the UEA-I binding pattern during the development of the rat gustatory epithelium. In adult animals, UEA-I bound to the membrane of taste buds in all examined regions of the gustatory epithelium. Within the individual taste buds, UEA-I labeled almost all intragemmal cells. The binding of UEA-I was occasionally detected below the keratinized layer of the trench wall epithelium but could not be found in the lingual epithelium of the adult animal. During the development of circumvallate papilla, some cells within the immature taste buds were also labeled with UEA-I. The developmental changes in the UEA-I binding pattern in fungiform papillae were almost identical to those in the circumvallate papilla: both immature and mature taste buds were labeled with UEA-I. The present results indicate that UEA-I is a specific lectin for the intragemmal cells of both immature and mature taste buds and, thus, UEA-I can be used as a reliable marker for all taste buds in the rat.

Immunohistochemical distribution of growth-associated protein 43 (GAP-43) in developing rat nasoincisor papilla.

We employed immunohistochemistry of growth-associated protein 43 (GAP-43) to trace the early development of gustatory nerves and alpha-gustducin to demonstrate mature taste buds in the rat nasoincisor papilla (NP). The sequential changes of gustatory structures revealed eight characteristic stages. One, at embryonic day 16 (E16), GAP-43-immunoreactive (IR) nerve fibers were observed in close relation with presumptive taste buds in the lateral apical epithelium on each side of NP; meanwhile, no immunoreactivity could be observed in the papillary epithelium. Two, at E17, fine GAP-43-IR nerve fibers first invaded the apical epithelium of the papilla. Three, at E19, GAP-43-IR nerve fibers were extensive in apical epithelium and colonized in immature taste buds. Four, at E20, GAP-43-IR nerve fibers were first observed in ductal epithelium (lining the medial wall of nasoincisor ducts). Five, at postnatal day 1 (P1), immunoreactive nerve fibers first coincided with immature taste buds in the ductal epithelium. Six, at P3, alpha-gustducin-IR cells identical for mature taste buds were simultaneously demonstrated in both apical and ductal epithelium. Seven, at P14, progressive taste bud proliferation and maturation as well as neural invasion were demonstrated in all regions of the epithelium. Eight, during advanced stage in adult animals, extensive innervation was traced especially in close relation with taste buds. The sequential topographic patterns of NP gustatory structures seem very specific as compared to those in other locations of mammalian gustatory system. The present study reveals that gustatory nerves preceded the development of taste buds. However, further investigations are required to examine such a characteristic model for the neurogenic theory of taste induction.

Human blood group antigen H is not the specific marker for type I cells in the taste buds.

We examined the localization of human blood antigen H (AbH) and its correlation with other cell type markers in the taste buds of circumvallate papillae of the adult rat. Immunoreactivity for AbH was localized in the membrane of two cell populations in the taste buds: in spindle-shaped cells extending from base to the apical portion of the taste buds as well as in round-shaped cells at the basal portion of the taste buds. Quantitative analysis revealed that approximately 47.8%, 24.4%, and 14.6% of cells within the taste buds displayed AbH-, alpha-gustducin- or protein gene product 9.5 (PGP 9.5)-immunoreactivity, respectively. Approximately 16.3% and 6.6% of AbH-immunoreactive taste bud cells displayed alpha-gustducin- or PGP 9.5-immunoreactivity, respectively. Although previous studies proposed that AbH immunoreactivity was specific for type I cells (dark cells or supporting cells), the present results indicate that AbH immunoreactivity is also present in some type II cells (alpha-gustducin immunoreactive cells) and type III cells (PGP 9.5-immunoreactive cells).

Immunohistochemical localization of heat shock protein 25 (HSP 25) during root formation of the rat molar.

The present study investigated the immunohistochemical localization of heat shock protein 25 (HSP 25) of rat molar teeth during root formation. Most, probably all, cells of the epithelial rest of Malassez (ERM cells) had immunoreaction for laminin, a marker protein for basement membrane. During root formation, HSP 25 immunoreactivity was observed in odontoblasts, cells at the subodontoblastic layer, and those in close proximity to the acellular cementum. HSP 25-immunopositive cells at the subodontoblastic layer were present only at the apical region. Most HSP 25-immunoreactive cells in close proximity to the cementum lacked laminin immunoreactivity. However, at postnatal day 28 a small number of cells showed immunoreaction for both HSP 25 and laminin at the cervical and bifurcational regions. Under the electron microscope, most HSP 25-immunoreactive cells along the surface of the cementum were round and contained rich organelles such as mitochondria and rough endoplasmic reticulum. They lay between fiber bundles of the periodontal ligament. The localization and morphological features of these HSP 25-immunoreactive cells resemble those of cementoblasts. On the other hand, HSP 25-immunoreactive cells at the cervical region were oval and contained few cell organelles. They were closely apposed to each other, and separated from the surrounding tissues with basal lamina. These features were similar to those of mature ERM cells. In contrast, cells with microvillus-like processes and relatively rich mitochondria, which were similar to immature ERM cells, had no immunoreaction for HSP 25. These results suggest that HSP 25 may be involved in shape alterations of ERM cells, cementoblasts, and odontoblasts during differentiation.