Imaging synaptic inhibition with the genetically encoded chloride indicator Clomeleon

Several techniques are available to image excitatory processes in the brain, but synaptic inhibition has remained largely invisible. Most synaptic inhibition in the brain arises from transmembrane fluxes of chloride ions (Cl(-)), so imaging intracellular Cl(-) concentration ([Cl(-)](i)) is, in principle, a natural way to visualize the spatiotemporal dynamics of inhibition. This protocol describes the use of Clomeleon, a genetically encoded indicator of Cl(-), as a tool for monitoring synaptic inhibition. It outlines procedures that can be used to image neuronal [Cl(-)](i) in brain slices prepared from Clomeleon transgenic mice. With only minor adjustments, the same procedures should be suitable for imaging from cultured cells as well.

Cell type–specific channelrhodopsin-2 transgenic mice for optogenetic dissection of neural circuitry function

Optogenetic methods have emerged as powerful tools for dissecting neural circuit connectivity, function and dysfunction. We used a bacterial artificial chromosome (BAC) transgenic strategy to express the H134R variant of channelrhodopsin-2, ChR2(H134R), under the control of cell type–specific promoter elements. We performed an extensive functional characterization of the newly established VGAT-ChR2(H134R)-EYFP, ChAT-ChR2(H134R)-EYFP, Tph2-ChR2(H134R)-EYFP and Pvalb(H134R)-ChR2-EYFP BAC transgenic mouse lines and demonstrate the utility of these lines for precisely controlling action-potential firing of GABAergic, cholinergic, serotonergic and parvalbumin-expressing neuron subsets using blue light. This resource of cell type–specific ChR2(H134R) mouse lines will facilitate the precise mapping of neuronal connectivity and the dissection of the neural basis of behavior.

[Effect of in-utero surgical repair at different stages on mid-facial development of goats with cleft palate]

OBJECTIVE

To study the mid-facial development characteristics of the goats with cleft palate after in-utero surgical repair at different stages.

METHODS

Twenty-four Boer hybrid female goats were selected, aged from 8 to 12 months and weighing from 35 to 55 kg. The mating day was designated for 0 day. At 30 days, pregnant was confirmed by B-ultrasound test, and the goats were divided into 5 groups (experimental groups 1, 2, 3, 4, and normal control group). Twenty pregnant goats of 4 experimental groups (n = 5) were injected DL-anabasine (15 mg/day) from 31 to 42 days to establish cleft palate model of fetal lamb, 4 pregnant goats of normal control group used as controls without injection. At pregnant 65, 90, and 120 days, cleft palate was repaired in the uterus in experimental groups 1, 2, and 3, while cleft palate was not repaired in experimental group 4. After 1 month of birth, the maxillary bone width (posterior premolar morphological measurement, PPMM) and the maxillary bone length (anterior premolar morphological measurement, APMM) were measured with CT scanning. The dry skull of goats were harvested for gross observation.

RESULTS

There was no significant difference in PPMM and APMM between experimental group 1 and the normal control group (P > 0.05), but there were significant differences between experimental groups 1 and 4 (P < 0.05) at 1 month after birth. Significant differences were observed in PPMM and APMM between experimental group 2 and normal control group, experimental group 4 (P < 0.05). There were significant differences in PPMM between experimental group 3 and normal control group, experimental group 4 (P < 0.05), in APMM between experimental group 3 and normal control group (P < 0.05). Five goats with cleft palate in experimental group 4 died at 1-2 months after birth.

CONCLUSION

At pregnant 65 days, in-utero surgical repair of cleft palate has less influences on mid-facial development. The earlier repair is performed, the higher risk of miscarriage was.

Neurobiology of obsessive-compulsive disorder: insights into neural circuitry dysfunction through mouse genetics

The precise causal factors for obsessive-compulsive disorder (OCD) are not known, although, decades of research have honed in on the cortico-striatal-thalamo-cortical (CSTC) circuitry in the brain as a critical pathway involved in obsessions and the intimately linked compulsive-repetitive behaviors. Recent progress in human and mouse genetics have led to the identification of novel candidate susceptibility genes, which in turn have facilitated a more focused approach to unraveling the nature of circuitry dysfunction in OCD. The ability to perform invasive techniques in genetic animal models of OCD will be crucial for rapid advances in this field, and as such we review the most recent developments and highlight the importance of searching out common circuitry defects underlying compulsive-repetitive behaviors.

Reduction malarplasty using an L-shaped osteotomy through intraoral and sideburns incisions

The slender, oval-shaped face is considered to be attractive in East Asia. To obtain the ideal contour of the midface, reduction malarplasty has been popularized in oriental countries in recent years. This report describes a surgical technique for reduction of the zygomatic body and arch. After labiobuccal vestibular incisions are made, the anterior zygomatic body and lateral orbital rim are exposed by subperiosteal dissection. Thereafter, an L-shaped osteotomy is performed. Two parallel horizontal osteotomies are made in the anterior part of the zygomatic body, and the middle bone segment is removed. The zygomatic arch root is fractured through a small sideburn incision just anterior to the articular tubercle. Finally, the freed zygomatic complex is medially repositioned and fixed with one or two bicortex screws. Operations on 32 patients demonstrated that this technique may be a sound method for malar complex reduction, with the advantages of simple manipulation, stable fixation, and less risk of a drooping face.

Annual Research Review: Transgenic mouse models of childhood-onset psychiatric disorders

Childhood-onset psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), mood disorders, obsessive compulsive spectrum disorders (OCSD), and schizophrenia (SZ), affect many school-age children, leading to a lower quality of life, including difficulties in school and personal relationships that persist into adulthood. Currently, the causes of these psychiatric disorders are poorly understood, resulting in difficulty diagnosing affected children, and insufficient treatment options. Family and twin studies implicate a genetic contribution for ADHD, ASD, mood disorders, OCSD, and SZ. Identification of candidate genes and chromosomal regions associated with a particular disorder provide targets for directed research, and understanding how these genes influence the disease state will provide valuable insights for improving the diagnosis and treatment of children with psychiatric disorders. Transgenic mouse models are one important approach in the study of human diseases, allowing for the use of a variety of experimental approaches to dissect the contribution of a specific chromosomal or genetic abnormality in human disorders. While it is impossible to model an entire psychiatric disorder in a single mouse model, these models can be extremely valuable in dissecting out the specific role of a gene, pathway, neuron subtype, or brain region in a particular abnormal behavior. In this review we discuss existing transgenic mouse models for childhood-onset psychiatric disorders. We compare the strength and weakness of various transgenic mouse models proposed for each of the common childhood-onset psychiatric disorders, and discuss future directions for the study of these disorders using cutting-edge genetic tools.

[An experimental study on chemically induced animal model of goat cleft palate in uterus]

OBJECTIVE

To study the method to prepare the animal model of goat cleft palate by injection of anabasine and the effect of the malformation on the development of the facial mid-part.

METHODS

A total of 40 female boer hybrid goats were selected, aging 8-12 months and weighing 35-55 kg. The mating day was 0 day, and at 30 days the goats assured pregnant by B type ultrasonic test were divided into 4 groups (n=10) according to intramuscular injection of 10 (experimental group 1), 15 (experimental group 2), 20 (experimental group 3) mg/d, and no injection (control group), respectively, from the 31st to 42nd day. At pregnant 120 days and 1 month after birth, 5 fetal goats of each group were used for three dimensional reconstruction of skull with CT scan. The maxillary bone width named as PPMM and the maxillary bone length named as APMM were measured, then the hard palate general observation was performed and dry skull of goats was harvested to observe the development of maxillary.

RESULTS

After injection, all pregnant lambs aborted in experimental group 3; 2 pregnant lambs aborted and 8 lambs maintained pregnancy in experimental group 2. At 120 days of pregnant, no cleft palate was observed in 5 fetal lambs of experimental group 1 and control group, respectively; cleft palate and maxillary dysplasia occurred in 3 fetal lambs of experimental group 2. Among 11 newborn lambs of experimental group 1 and 8 newborn lambs of control group, no cleft palate was observed; among 7 newborn lambs of experimental group 2, cleft palate occurred in 5 with obvious maxillary dysplasia and eating difficulty. General observation of hard palate and dry skull showed obvious hypoplasia of maxillary in experimental group 2. There were significant differences in PPMM and APMM between the experimental group 2 and the control group at pregnant 120 days and 1 month after birth (P < 0.05). Five lambs with cleft palates of experimental group 2 survived for 1-2 months.

CONCLUSION

The animal models of goat cleft palate can established by intramuscular injection of anabasine at a dose of 15 mg/d from the 31st to 42nd day of pregnant. The facial character of the induced cleft palate goat is similar to that of human cleft palate.

Abstract P5-06-04: Nicastrin Reveals Gamma-Secretase Independent Function in Breast Cancer Cells and Can Be Targeted by a Blocking Monoclonal Antibody To Reduce Breast Cancer Cell Proliferation and Invasion

BACKGROUND: Nicastrin (NCT) is a structural and functional part of the gamma-secretase (GS) enzyme, implicated in tumorigenesis and resistance to treatment in multiple cancer types. However, its mechanism(s) of action and biological functions are poorly understood. We investigated functional and biological effects of inhibiting NCT in breast cancer (BC)cells by means of gene silencing and blocking antibodies, as well as the prognostic value of NCT expression in BC tissue. METHODS: NCT siRNA (Dahrmacon) was used at 40nM. A polyclonal antibody (pcAb) against NCT extracellular domain was developed at Biogenes (GE), and anti-NCT monoclonal antibodies (mAbs) at Genovac (GE). We tested the Abs for their ability to recognize endogenous NCT in BC cells by FACS and Western blot. Best Abs were tested in vitro, using a transwell cell invasion assay and proliferation assay. Anti-NCT Ab (Sigma, N1660) was used for immunohistochemistry (IHC) staining of BC tissues (n = 1050). Cases were scored as NCT negative (0), 1+, 2+ or 3+. Kaplan Meier analysis was used to investigate impact of NCT expression on survival. Illumina (Agilent) oligonucleotide arrays were used to investigate NCT siRNA effects on gene expression in BC cells. Both PcAb and mAbs recognized endogenous NCT in BC cells. In vitro, blocking NCT in MDA-MB231 BC cells with the PcAb, reduced cell proliferation in a dose dependent manner; by 50% and 70% at concentrations of 50μg/ml and 100μg/ml, respectively. mAbs reduced proliferation by 50% (clones 2H6 and 10C5) and 70% clone 10C11, (P&lt;0.01). In transwell cell invasion assay, anti-NCT pcAb induced a dose dependent reduction of invasion, by 35% at the 5μg/ml, peaking at &gt; 60% reduction at 50μg/ml (P&lt;0.001). mAbs reduced cell invasion by 40-50% (clone 10C5 and 10C11) and by &gt;65% (clone 2H6) (P&lt;001). IHC data showed that NCT was highly expressed (2+, 3+) in 47.5% of BC tissues. High NCT expression correlated with worse overall survival (OS) in ERnegative patients (p=0.05). To elucidate the effects of NCT loss, compared to those induced by GSIs or silencing Notch receptors, we examined cDNA from MDA231 treated independently with NCT, Notch1, Notch2, Notch4 siRNAs and GSI MK-003, on Illumina expression arrays. Thirteen of the 18 genes maximally affected by GSI were similarly affected by NCT siRNA. NCT knockdown also affected 1745 other genes that by large were not affected by GSI or Notch knockdowns. This suggests that NCT has GS-and Notch-independent cellular functions and may have different biological properties as a therapeutic target than GS. Among NCT siRNA affected genes, some are tumor suppressors: CST4 increased 8 fold; pro-invasive genes like GNG11 decreased 4 fold; cell adhesion genes: CTGF increased 4.5 fold etc.

CONCLUSIONS: NCT is overexpressed in 47.5% of BC cases where it infers adverse OS in the ER-vecohort of patients. Anti-NCT mAbs recognize endogenous NCT in BC cells and reduce BC cell proliferation and invasion. Silencing NCT in invasive BC cells induces extensive gene expression changes that only partially overlap with those caused by GSIs or Notch siRNAs. We conclude that NCT has GS-independent functions in BC cells and that an anti-NCT mAb may be a promising therapeutic approach for invasive BC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-06-04.

Regulation of pancreatic islet gene expression in mouse islets by pregnancy

Pancreatic β cells adapt to pregnancy-induced insulin resistance by unclear mechanisms. This study sought to identify genes involved in β cell adaptation during pregnancy. To examine changes in global RNA expression during pregnancy, murine islets were isolated at a time point of increased β cell proliferation (E13.5), and RNA levels were determined by two different assays (global gene expression array and G-protein-coupled receptor (GPCR) array). Follow-up studies confirmed the findings for select genes. Differential expression of 110 genes was identified and follow-up studies confirmed the changes in select genes at both the RNA and protein level. Surfactant protein D (SP-D) mRNA and protein levels exhibited large increases, which were confirmed in murine islets. Cytokine-induced expression of SP-D in islets was also demonstrated, suggesting a possible role as an anti-inflammatory molecule. Complementing these studies, an expression array was performed to define pregnancy-induced changes in expression of GPCRs that are known to impact islet cell function and proliferation. This assay, the results of which were confirmed using real-time reverse transcription-PCR assays, demonstrated that free fatty acid receptor 2 and cholecystokinin receptor A mRNA levels were increased at E13.5. This study has identified multiple novel targets that may be important for the adaptation of islets to pregnancy.

Systemic treatment with strontium ranelate promotes tibial fracture healing in ovariectomized rats

Systemic treatment with strontium ranelate (SR) was performed on ovariectomized (OVX) rats with fractured tibiae. Callus quality was assessed by radiographic, histological, micro-computerized tomography, and biomechanical examinations at 4 and 8 weeks after fracture. Results revealed that systemic applied SR promoted osteoporotic fracture healing.

INTRODUCTION

Several studies have demonstrated the dual effect of SR on osteoporotic and undisturbed bone. However, reports of their effect on osteoporotic fracture healing are limited. This study was designed to investigate the effects of SR on bone regeneration in OVX rats with fractured tibiae.

METHODS

Three months after being OVX, female Sprague-Dawley rats accepted bilateral osteotomy on proximal tibiae fixed with intramedullary wires and were divided into two groups: OVX and OVX + SR (625 mg/kg/day). Callus quality was evaluated at 4 and 8 weeks postfracture.

RESULTS

Compared with OVX group, SR treatment significantly increased bone formation, BMD, biomechanical strength, and improved microstructural properties of the callus. The ultimate load was increased by 211.0% and 61.4% (p<0.01), and the total bone volume of callus by 74.8% and 79.3% (p<0.01) at 4 and 8 weeks postfracture, respectively. SR treatment also promoted healing progress with increased osteogenesis at 4 weeks; more mature and tightly arranged woven or lamellar bone at 8 weeks across the fracture gap in histological analysis.

CONCLUSION

This study suggests that systemic treatment with strontium ranelate could promote tibial fracture healing in OVX rats.

Pulse labeling and long-term tracing of newborn neurons in the adult subgranular zone

Research over the past decades has demonstrated that adult brain produces neural progenitor cells which proliferate and differentiate to newborn neurons that integrate into the existing circuit. However, detailed differentiation processes and underlying mechanisms of newly generated neurons are largely unknown due to the limitation of available methods for labeling and manipulating neural progenitor cells and newborn neurons. In this study, we designed a tightly controlled, noninvasive system based on Cre/loxP recombination to achieve long-term tracing and genetic manipulation of adult neurons in vivo. In this system, tamoxifen-inducible recombinase, CreER(T2), was driven by BAC-based promoter of doublecortin (DCX, a marker of newborn neurons). By crossing this Cre line with reporter mouse, we found that newborn neurons in the dentate gyrus (DG) could be selectively pulse-labeled by tamoxifen-induced expression of yellow fluorescent protein (YFP). YFP-positive neurons were identified by coimmunostaining with cell type-specific markers and characterized by electrophysiological recording. Furthermore, analysis of the migration of these neurons showed that the majority of these labeled neurons migrated to the inner part of granule cell layer. Moreover, spine growth of inner molecular layer of newborn granule neurons takes a dynamic pattern of invert U-shape, in contrast to the wedge-shaped change in the outer molecular layer. Our transgenic tool provides an efficient way to selectively label and manipulate newborn neuron in adult mouse DG.

Thermoaciduric Clostridium pasteurianum spoilage of shelf-stable apple juice

Clostridium pasteurianum BB, a saccharolytic and spore-forming obligate anaerobe, was isolated and identified from shelf-stable apple juice that was responsible for multiple large spoilage outbreaks. The growth and sporulation conditions of C. pasteurianum were atypical compared with those previously published. C. pasteurianum spores were heat resistant in apple juice at pH 3.80, with D-values at 80, 85, and 90°C being 34.4, 15.9, and 4.4 min, respectively, and a z-value of 11°C. The survival curves for thermal inactivation obeyed linear first-order kinetics. Apple juice with varying pH values was used to determine the effect of pH on germination capability of C. pasteurianum spores. The spores were found to be able to germinate at pH as low as 4.3 in pH-adjusted apple juice at low contamination levels. It was confirmed by PCR that C. pasteurianum isolated from spoiled apple juice did not contain the genes for botulinum toxins B and E, which were more commonly found in neurotoxigenic butyric clostridia. Control of finished-juice pH to below 4.0 in combination with mild heating was proposed to prevent potential spoilage of shelf-stable apple juice made with spore-contaminated apple juice concentrate.