Neuronal PAS Domain Proteins 1 and 3 Are Master Regulators of Neuropsychiatric Risk Genes

BACKGROUND

NPAS3 has been established as a robust genetic risk factor in major mental illness. In mice, loss of neuronal PAS domain protein 3 (NPAS3) impairs postnatal hippocampal neurogenesis, while loss of the related protein NPAS1 promotes it. These and other findings suggest a critical role for NPAS proteins in neuropsychiatric functioning, prompting interest in the molecular pathways under their control.

METHODS

We used RNA sequencing coupled with chromatin immunoprecipitation sequencing to identify genes directly regulated by NPAS1 and NPAS3 in the hippocampus of wild-type, Npas1^-/-, and Npas3^-/- mice. Computational integration with human genetic and expression data revealed the disease relevance of NPAS-regulated genes and pathways. Specific findings were confirmed at the protein level by Western blot.

RESULTS

This is the first in vivo, transcriptome-scale investigation of genes regulated by NPAS1 and NPAS3. These transcription factors control an ensemble of genes that are themselves also major regulators of neuropsychiatric function. Specifically, Fmr1 (fragile X syndrome) and Ube3a (Angelman syndrome) are transcriptionally regulated by NPAS3, as is the neurogenesis regulator Notch. Dysregulation of these pathways was confirmed at the protein level. Furthermore, NPAS1/3 targets show increased human genetic burden for schizophrenia and intellectual disability.

CONCLUSIONS

Together, these data provide a clear, unbiased view of the full spectrum of genes regulated by NPAS1 and NPAS3 and show that these transcription factors are master regulators of neuropsychiatric function. These findings expose the molecular pathophysiology of NPAS1/3 mutations and provide a striking example of the shared, combinatorial nature of molecular pathways that underlie diagnostically distinct neuropsychiatric conditions.

The Eating-Disorder Associated HDAC4A778T Mutation Alters Feeding Behaviors in Female Mice

BACKGROUND

While eating disorders (EDs) are thought to result from a combination of environmental and psychological stressors superimposed on genetic vulnerability, the neurobiological basis of EDs remains incompletely understood. We recently reported that a rare missense mutation in the gene for the transcriptional repressor histone deacetylase 4 (HDAC4) is associated with the risk of developing an ED in humans.

METHODS

To understand the biological consequences of this missense mutation, we created transgenic mice carrying this mutation by introducing the alanine to threonine mutation at position 778 of mouse Hdac4 (corresponding to position 786 of the human protein). Bioinformatic analysis to identify Hdac4-regulated genes was performed using available databases.

RESULTS

Male mice heterozygous for HDAC4^A778T did not show any metabolic or behavioral differences. In contrast, female mice heterozygous for HDAC4^A778T display several ED-related feeding and behavioral deficits depending on housing condition. Individually housed HDAC4^A778T female mice exhibit reduced effortful responding for high-fat diet and compulsive grooming, whereas group-housed female mice display increased weight gain on high-fat diet, reduced behavioral despair, and increased anxiety-like behaviors. Bioinformatic analysis identifies mitochondrial biogenesis including synthesis of glutamate/gamma-aminobutyric acid as a potential transcriptional target of HDAC4^A778T activity relevant to the behavioral deficits identified in this new mouse model of disordered eating.

CONCLUSIONS

The HDAC4^A778T mouse line is a novel model of ED-related behaviors and identifies mitochondrial biogenesis as a potential molecular pathway contributing to behavioral deficits.

Loss of estrogen-related receptor alpha disrupts ventral-striatal synaptic function in female mice

Eating disorders (EDs), including anorexia nervosa, bulimia nervosa and binge-ED, are mental illnesses characterized by high morbidity and mortality. While several studies have identified neural deficits in patients with EDs, the cellular and molecular basis of the underlying dysfunction has remained poorly understood. We previously identified a rare missense mutation in the transcription factor estrogen-related receptor alpha (ESRRA) associated with development of EDs. Because ventral-striatal signaling is related to the reward and motivation circuitry thought to underlie EDs, we performed functional and structural analysis of ventral-striatal synapses in Esrra-null mice. Esrra-null female, but not male, mice exhibit altered miniature excitatory postsynaptic currents on medium spiny neurons (MSNs) in the ventral striatum, including increased frequency, increased amplitude, and decreased paired pulse ratio. These electrophysiological measures are associated with structural and molecular changes in synapses of MSNs in the ventral striatum, including fewer pre-synaptic glutamatergic vesicles and enhanced GluR1 function. Neuronal Esrra is thus required for maintaining normal synaptic function in the ventral striatum, which may offer mechanistic insights into the behavioral deficits observed in Esrra-null mice.

The Neuropsychiatric Disease-Associated Gene cacna1c Mediates Survival of Young Hippocampal Neurons

Genetic variations in CACNA1C, which encodes the Cav1.2 subunit of L-type calcium channels (LTCCs), are associated with multiple forms of neuropsychiatric disease that manifest high anxiety in patients. In parallel, mice harboring forebrain-specific conditional knockout of cacna1c (forebrain-Cav1.2 cKO) display unusually high anxiety-like behavior. LTCCs in general, including the Cav1.3 subunit, have been shown to mediate differentiation of neural precursor cells (NPCs). However, it has not previously been determined whether Cav1.2 affects postnatal hippocampal neurogenesis in vivo. Here, we show that forebrain-Cav1.2 cKO mice exhibit enhanced cell death of young hippocampal neurons, with no change in NPC proliferation, hippocampal size, dentate gyrus thickness, or corticosterone levels compared with wild-type littermates. These mice also exhibit deficits in brain levels of brain-derived neurotrophic factor (BDNF), and Cre recombinase-mediated knockdown of adult hippocampal Cav1.2 recapitulates the deficit in young hippocampal neurons survival. Treatment of forebrain-Cav1.2 cKO mice with the neuroprotective agent P7C3-A20 restored the net magnitude of postnatal hippocampal neurogenesis to wild-type levels without ameliorating their deficit in BDNF expression. The role of Cav1.2 in young hippocampal neurons survival may provide new approaches for understanding and treating neuropsychiatric disease associated with aberrations in CACNA1C. Visual Abstract.

Behavioral disturbances in estrogen-related receptor alpha-null mice

Eating disorders, such as anorexia nervosa and bulimia nervosa, are common and severe mental illnesses of unknown etiology. Recently, we identified a rare missense mutation in the transcription factor estrogen-related receptor alpha (ESRRA) that is associated with the development of eating disorders. However, little is known about ESRRA function in the brain. Here, we report that Esrra is expressed in the mouse brain and demonstrate that Esrra levels are regulated by energy reserves. Esrra-null female mice display a reduced operant response to a high-fat diet, compulsivity/behavioral rigidity, and social deficits. Selective Esrra knockdown in the prefrontal and orbitofrontal cortices of adult female mice recapitulates reduced operant response and increased compulsivity, respectively. These results indicate that Esrra deficiency in the mouse brain impairs behavioral responses in multiple functional domains.

P7C3 neuroprotective chemicals block axonal degeneration and preserve function after traumatic brain injury

The P7C3 class of neuroprotective aminopropyl carbazoles has been shown to block neuronal cell death in models of neurodegeneration. We now show that P7C3 molecules additionally preserve axonal integrity after injury, before neuronal cell death occurs, in a rodent model of blast-mediated traumatic brain injury (TBI). This protective quality may be linked to the ability of P7C3 molecules to activate nicotinamide phosphoribosyltransferase, the rate-limiting enzyme in nicotinamide adenine dinucleotide salvage. Initiation of daily treatment with our recently reported lead agent, P7C3-S243, 1 day after blast-mediated TBI blocks axonal degeneration and preserves normal synaptic activity, learning and memory, and motor coordination in mice. We additionally report persistent neurologic deficits and acquisition of an anxiety-like phenotype in untreated animals 8 months after blast exposure. Optimized variants of P7C3 thus offer hope for identifying neuroprotective agents for conditions involving axonal damage, neuronal cell death, or both, such as occurs in TBI.

Effect of nutrient addition and environmental factors on prophage induction in natural populations of marine synechococcus species

A series of experiments were conducted with samples collected in both Tampa Bay and the Gulf of Mexico to assess the impact of nutrient addition on cyanophage induction in natural populations of Synechococcus sp. The samples were virus reduced to decrease the background level of cyanophage and then either left untreated or amended with nitrate, ammonium, urea, or phosphate. Replicate samples were treated with mitomycin C to stimulate cyanophage induction. In five of the nine total experiments performed, cyanophage induction was present in the non-nutrient-amended control samples. Stimulation of cyanophage induction in response to nutrient addition (phosphate) occurred in only one Tampa Bay sample. Nutrient additions caused a decrease in lytic (or control) phage production in three of three offshore stations, in one of three estuarine experiments, and in a lysogenic marine Synechococcus in culture. These results suggest that the process of cyanophage induction as an assay of Synechococcus lysogeny was not inorganically nutrient limited, at least in the samples examined. More importantly, it was observed that the level of cyanophage induction (cyanophage milliliter(-1)) was inversely correlated to Synechococcus and cyanophage abundance. Thus, the intensity of the prophage induction response is defined by ambient population size and cyanophage abundance. This corroborates prior observations that lysogeny in Synechococcus is favored during times of low host abundance.

A protein interaction map of Drosophila melanogaster

Drosophila melanogaster is a proven model system for many aspects of human biology. Here we present a two-hybrid-based protein-interaction map of the fly proteome. A total of 10,623 predicted transcripts were isolated and screened against standard and normalized complementary DNA libraries to produce a draft map of 7048 proteins and 20,405 interactions. A computational method of rating two-hybrid interaction confidence was developed to refine this draft map to a higher confidence map of 4679 proteins and 4780 interactions. Statistical modeling of the network showed two levels of organization: a short-range organization, presumably corresponding to multiprotein complexes, and a more global organization, presumably corresponding to intercomplex connections. The network recapitulated known pathways, extended pathways, and uncovered previously unknown pathway components. This map serves as a starting point for a systems biology modeling of multicellular organisms, including humans.

Seasonal variation in lysogeny as depicted by prophage induction in Tampa Bay, Florida

A seasonal study of the distribution of lysogenic bacteria in Tampa Bay, Florida, was conducted over a 13-month period. Biweekly water samples were collected and either were left unaltered or had the viral population reduced by filtration (pore size, 0.2 micro m) and resuspension in filtered (pore size, 0.2 micro m) water. Virus-reduced and unaltered samples were then treated by adding mitomycin C (0.5 micro g ml(-1)) to induce prophage or were left untreated. In order to test the hypothesis that prophage induction was phosphate limited, additional induction experiments were performed in the presence and absence of phosphate. Induction was assessed as an increase in viral direct counts, relative to those obtained in controls, as detected by epifluorescence microscopy. Induction of prophage was observed in 5 of 25 (20%) unaltered samples which were obtained during or after the month of February, paralleling the results from a previous seasonal study. Induction of prophage was observed in 9 of 25 (36%) of the virus-reduced samples, primarily those obtained in the winter months, which was not observed in a prior seasonal study (P. K. Cochran and J. H. Paul, Appl. Environ. Microbiol. 64:2308-2312, 1998). Induction was noted in the months of lowest bacterial and primary production, suggesting that lysogeny was favored under conditions of poor host growth. Phosphate addition enabled prophage induction in two of nine (22%) experiments. These results indicate that prophage induction may occasionally be phosphate limited or respond to increases in phosphate concentration, suggesting that phosphate concentration may modulate the lysogenic response of natural populations.

Lysogeny in marine Synechococcus

Viral infection of bacteria can be lytic, causing destruction of the host cell, or lysogenic, in which the viral genome is instead stably maintained as a prophage within its host. Here we show that lysogeny occurs in natural populations of an autotrophic picoplankton (Synechococcus) and that there is a seasonal pattern to this interaction. Because lysogeny confers immunity to infection by related viruses, this process may account for the resistance to viral infection seen in common forms of autotrophic picoplankton.

Evaluation of marine bacterial lysogens for development of a marine prophage induction assay

The demonstrated relationship between carcinogenicity of a chemical compound in mammals and its tendency to cause prophage induction in bacteria provides a method for biologically based carcinogen screening. Because of the need for this type of screening and the abundance of lysogens in the marine environment, 14 isolates were evaluated for the degree of prophage induction in exponentially growing cultures in the presence of a known mutagen (0.5 microg/ml mitomycin C). Assays were performed both in liquid culture and in microtiter plates. Virus-like particles were enumerated by epifluorescence microscopy after staining with SYBR-Gold. Two isolates designated P94-4B3 (identified as Halomonas aquamarina) and P94-4S3 (identified as Pseudomonas aeruginosa) were further evaluated for potential use. Because of the rapid growth, larger size of its virus-like particles, and linear response to increasing dose of mitomycin C, the P. aeruginosa st. P94-4S3 was determined a better candidate for the marine prophage induction assay (MPIA). The Pseudomonas isolate was then used in several experiments for the development and optimization of the MPIA procedure. Initial screenings of the MPIA were also performed with selected environmental pollutants.

Congenital digital deformities

Congenital digital deformities are often challenging to treat. Several deformities and their treatments are discussed. Familiarity with the deformities is important because early treatment is often necessary for a successful outcome.

Patient management after endoscopic removal of the cancerous colon adenoma

The subject of management of patients after endoscopic removal of cancerous adenomas is controversial. A retrospective review of 126 lesions in 121 patients who had had colonoscopic polypectomy of malignant lesions between 1971 and 1985 was used to determine the criteria for colon resection. Invasive cancer was identified in 80 patients, while 41 patients had carcinoma in situ. A synchronous colon cancer was found in five of the 121 patients. The patients who had carcinoma in situ had no evidence of residual tumor or metastatic disease on subsequent follow-up (colon resection in three patients and endoscopic surveillance in 38 patients). Of the 80 patients with invasive cancer, 44 had subsequent colon resection, and 34 of these had no evidence of tumor in the resected bowel or mesenteric lymph nodes. Ten patients had residual tumor, metastatic cancer to regional lymph nodes, or both. Each of the 10 had at least one of the following indications of inadequate resection or dissemination of disease to local lymph nodes (the first indication is a macroscopic evaluation, while the remaining four are all microscopic): incomplete excision, poorly differentiated tumor, invasion of the line of resection, invasion of the polyp stalk, and invasion of venous or lymphatic channels. Present recommendations for patient management after endoscopic removal of an invasive malignant adenoma should include colon resection with regional lymphadenectomy for patients with one or more of these five criteria. Patients without any of these risk factors should have early repeat endoscopic examination 3 months after initial polypectomy to evaluate the polypectomy site. Total colonoscopic examination is repeated at 1 year to ensure the surveillance program is begun with a colon without neoplasms.

Experience with 1000 colonoscopic polypectomies

Experience with 1000 consecutive polypectomies in 591 patients, from December 1975 to October 1982, is reviewed. There were 633 adenomas, 292 hyperplastic, and 75 miscellaneous polyps. While eight minor bleeding episodes (0.8%) occurred, there were no major complications (perforations or bleeding requiring transfusion). The polyp retrieval rate was 97.9%. Of the 633 adenomas, seven (1.1%) had in situ carcinoma and ten (1.6%) invasive. Eight of the invasive group underwent colon resection with no positive nodes present. Anatomic location demonstrated a shift to the right side of the colon. Three hundred thirty-six (53.1%) were in the rectosigmoid; 134 (21.3%) were in the left colon; 79 (12.3%) were in the transverse colon; and 84 (13.3%) were in the right colon and cecum. Patients who have undergone benign polypectomy are colonoscoped again in 1 year, and, if negative, every 3 years thereafter. Postpolypectomy patients with malignant adenomas require closer observation. Endoscopic polypectomy, with its lower morbidity and mortality, has revolutionized the treatment of the colon polyp. It is also more cost-effective, with outpatient polypectomy being 29 times less expensive and inpatient polypectomy four times less expensive than transabdominal polypectomy.

The use of endoscopy in assessment and treatment peptic strictures of the esophagus

In the 1960s, evaluation of peptic strictures of the esophagus was a significant and difficult clinical problem. The use of rigid esophagoscopes and general anesthesia resulted in high complication rates. Most peptic esophageal strictures were managed surgically. The 1970s brought a dramatic change in the management of peptic strictures of the esophagus. With the introduction and widespread use of the forward-viewing, flexible panendoscope for upper gastrointestinal (GI) endoscopy, general anesthesia is no longer needed; evaluation of the peptic stricture has become one of the most common procedures in GI endoscopy. From December 1975 to October 1982, 1000 dilations were performed with a morbidity of 0.2 per cent and a mortality of 0.1 per cent. Initially, radiographic evaluation proximal to, distal to, and at the stricture is conducted. Endoscopic evaluation of the same three areas is then performed with emphasis on determining whether the stricture is benign or malignant. Malignancy can be determined visually in more than 90 per cent of the patients and in more than 95 per cent of the patients with multiple biopsies and cytology. Immediate dilation, using rubber (Maloney) dilators (Pilling Medical Co., Fort Washington, PA) or Eder-Puestow dilators (Eder Instrument Co., Chicago, IL), is then performed. The personality of the stricture determines which dilator can be used with greatest safety.

Foreign bodies of the upper gastrointestinal tract: current management

The popularity of the flexible esophagogastroduodenoscope prompted us to reevaluate our management of foreign bodies. In this paper we report our experience and update treatment guidelines. In our series (from December 1975 to May 1982), 74 foreign bodies were removed: 12 with the rigid endoscope, 60 with the flexible endoscope, and two surgically. There was no morbidity or mortality. In the age group 1 to 10 years, there were 15 patients, while the age group 11 to 88 years had 59 patients. Although the rigid endoscope is less expensive and has a larger operating channel, the advantages of the flexible instrument are numerous. Foreign bodies of the pharynx and at the level of the cricopharyngeus muscle are best managed with a rigid endoscope; foreign bodies of the esophagus can be managed with rigid or flexible instruments, but are more easily managed with the latter. Foreign bodies of the stomach and duodenum that require removal can be managed only with the flexible panendoscope.

Endoscopic evaluation of dysphagia in two hundred and ninety-three patients with benign disease

A total of 538 dilations were performed upon 293 patients evaluated at our unit. Of these, 4.8 per cent had cervical webs, 3.0 per cent had cricopharyngeal dysfunction, 9.2 per cent had undetermined cause, 3.4 per cent had achalasia, 65.5 per cent had peptic strictures, 3.8 per cent had Schatzki's ring, 2.4 per cent had esophagitis, 6.1 per cent had postoperative strictures, 0.3 per cent had caustic stricture and 1.4 per cent had extrinsic compression. True dysphagia should always be investigated through a careful history, physical examination, barium study, endoscopy and, infrequently, esophageal manometry.

Endoscopic evaluation of 125 cases of upper gastrointestinal bleeding

The fiberoptic panendoscope has been shown to be superior to the UGI series in diagnosing the site(s) of upper gastrointestinal bleeding (UGIB). Recent data has shown that gastritis has replaced peptic ulcer disease (PUD) as the leading cause of UGIB since the diagnosis can now be made with the endoscope. Our clinical experience differs from this. One hundred twenty five cases of UGIB from December 1975 to December 1978 were reviewed. The patients ranged in age from 11 to 91 years. There were 83 males and 42 females included in the study. Twenty-four per cent of the patients were actively bleeding at the time of endoscopic examination, and 62% received two or more units of blood. Endoscopic examination was technically successful in all patients, and there were no deaths or complications. One hundred twenty three lesions were found in 117 patients for a diagnostic accuracy of 93.9%. In eight patients, no bleeding site was found, resulting in a failure rate of 6.1%. PUD accounted for 74.9% of the bleeding sites, while gastritis accounted for only 0.8%. Mallory-Weiss tears of the esophagus accounted for 9.8% and esophageal varices for 4.9%. Thirty-five per cent of the patients had associated lesions, with gastritis and esophagitis being the most common. Eighteen patients (14.4%) required surgical intervention. Seventeen patients had PUD. There was one death, for a mortality rate of 5.5%. The medical mortality rate was 0.9%. The benefits of endoscopy in UGIB are still controversial. An important subgroup of patients with the "visible vessel" in the ulcer bed has been identified recently by others. If not bleeding at the time of endoscopy, 70% will rebleed. It is our opinion that it is important to identify this patient, as well as to know if one is treating gastritis, PUD, or varices. Finally, electrocoagulation of bleeding points, as well as the development of the laser and application of adhesives or clotting agents through the endoscope, will change the management of UGIB.