Drug Addiction and DNA Modifications.

Drug addiction is a complex disorder which can be influenced by both genetic and environmental factors. Research has shown that epigenetic modifications can translate environmental signals into changes in gene expression, suggesting that epigenetic changes may underlie the causes and possibly treatment of substance use disorders. This chapter will focus on epigenetic modifications to DNA, which include DNA methylation and several recently defined additional DNA epigenetic changes. We will discuss the functions of DNA modifications and methods for detecting them, followed by a description of the research investigating the function and consequences of drug-induced changes in DNA methylation patterns. Understanding these epigenetic changes may provide us translational tools for the diagnosis and treatment of addiction in the future.

Assessing the value of endoscopic ultrasound in predicting symptom severity and long-term clinical course in chronic pancreatitis.

BACKGROUND: To date, no studies have evaluated the correlation between number of endoscopic ultrasound (EUS) criteria met for chronic pancreatitis (CP) and symptom severity over the course of the disease. This study assessed the relationship between number of EUS-based diagnostic criteria for CP and CP severity over time. METHODS: A University of Louisville database was queried for patients undergoing EUS due to concern for chronic pancreatitis between 2005 and 2016. Patients were grouped based on EUS criteria met for CP and groups were compared along outcome and procedural variables. RESULTS: Of a total of 243 patients, 24, 129, and 90 patients met 1-3, 4-5, and ≥6 EUS diagnostic criteria, respectively. Median follow-up time was 33 months. Along all follow-up parameters, number of diagnostic criteria was positively correlated with an increased percentage of patients requiring operative intervention for chronic pancreatitis on univariate and multivariate analysis. CONCLUSIONS: In addition to the role of EUS criteria in establishing the diagnostic severity of patients with symptomatic chronic pancreatitis, the number of EUS-based criteria may help predict patients who will eventually require operative intervention and thus prompt referral to a pancreatobiliary surgeon earlier in the course of a patient's disease.

Surgical Diagnoses of Pancreatic Adenocarcinoma Not Found on Previous Endoscopic Ultrasound: A Case Series and Review of the Literature.

INTRODUCTION: Pancreatic cancer is a leading cause of death in North America and Western Europe with rising rates in the developing world. Endoscopic ultrasound (EUS) with FNA (fine needle aspiration) is a critical component in the evaluation and diagnosis of pancreatic lesions with a high sensitivity and specificity. In this paper, we report patients at our center who eventually developed pancreatic cancer despite an early negative EUS, and identifying factors that may result in a missed diagnosis. METHODS: The University of Louisville database was queried for patients who had a Whipple procedure for presumed benign disease and had a pre-operative EUS between 2008 and 2018. Patients who had pancreatic adenocarcinoma on final pathology were identified. Demographic, clinical, EUS, operative, and pathologic details were reviewed for each case in efforts to identify factors associated with failure to diagnose a pancreatic malignancy on EUS. RESULTS: Five patients who had pancreatic adenocarcinoma on final pathology were reviewed in detail and their cases are presented in the paper. Four of the patients had dilation of the common bile duct, three had chronic pancreatitis. Two of them had previous surgery on the pancreas or bile ducts. CONCLUSIONS: All of the patients presented in the paper had variables that made their EUS evaluation challenging. A high index of suspicion must be maintained in patients that do not improve after appropriate treatment of their strictures or pancreatic lesions. In the future, new techniques, such as fine needle biopsy and biomarker assays, may improve diagnosis accuracy.

Limosilactobacillus reuteri administration alters the gut-brain-behavior axis in a sex-dependent manner in socially monogamous prairie voles.

Research on the role of gut microbiota in behavior has grown dramatically. The probiotic L. reuteri can alter social and stress-related behaviors - yet, the underlying mechanisms remain largely unknown. Although traditional laboratory rodents provide a foundation for examining the role of L. reuteri on the gut-brain axis, they do not naturally display a wide variety of social behaviors. Using the highly-social, monogamous prairie vole (Microtus ochrogaster), we examined the effects of L. reuteri administration on behaviors, neurochemical marker expression, and gut-microbiome composition. Females, but not males, treated with live L. reuteri displayed lower levels of social affiliation compared to those treated with heat-killed L. reuteri. Overall, females displayed a lower level of anxiety-like behaviors than males. Live L. reuteri-treated females had lower expression of corticotrophin releasing factor (CRF) and CRF type-2-receptor in the nucleus accumbens, and lower vasopressin 1a-receptor in the paraventricular nucleus of the hypothalamus (PVN), but increased CRF in the PVN. There were both baseline sex differences and sex-by-treatment differences in gut microbiome composition. Live L. reuteri increased the abundance of several taxa, including Enterobacteriaceae, Lachnospiraceae NK4A136, and Treponema. Interestingly, heat-killed L. reuteri increased abundance of the beneficial taxa Bifidobacteriaceae and Blautia. There were significant correlations between changes in microbiota, brain neurochemical markers, and behaviors. Our data indicate that L. reuteri impacts gut microbiota, gut-brain axis and behaviors in a sex-specific manner in socially-monogamous prairie voles. This demonstrates the utility of the prairie vole model for further examining causal impacts of microbiome on brain and behavior.

Regulation of BDNF expression by cocaine.

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors. It is expressed throughout the nervous system. A unique feature of the BDNF gene is the existence of multiple mRNA transcripts, all of which are translated into BDNF protein, suggesting a multilevel regulation of expression. In particular, the BDNF exon IV promoter region is a preferential target for epigenetic alterations, as it contains binding sites for CREB and MeCP2, two transcriptional regulators known to mediate epigenetic changes. Exposure to drugs of abuse is known to modulate epigenetic regulation of BDNF gene expression. This review will discuss how exposure to cocaine, one of the most addictive drugs known to mankind, can produce alterations in BDNF gene expression, especially in the mesolimbic dopaminergic system, which lead to alterations in the reward-mediated behaviors involved in addiction.

Long-term Follow-up of Patients Undergoing Endoscopic Intervention for Abdominal Pain with Minimal Biliary Ductal Dilation, Stone Disease, or Malignancy.

BACKGROUND: Safety and efficacy of endoscopic methods in management of biliary colic after cholecystectomy in patients with minimal biliary ductal dilation and no evidence of biliary stones or malignancy have not been clearly demonstrated. This study aimed to assess the efficacy of endoscopic management of such patients. METHODS: The University of Louisville database was queried for patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for colicky abdominal pain between 1996 and 2016 who had a common bile duct (CBD) diameter of ≤12 mm. All patients had undergone prior cholecystectomy and were free of malignancy. Demographic, serologic, procedural, and outcome variables were assessed. RESULTS: A total of 35 patients underwent a total of 99 ERCPs. Median CBD diameter was 10 (range 4-12) mm. A total of 31 patients (89%) underwent sphincterotomy, 28 (80%) underwent stent placement, and 5 (14%) underwent balloon dilation. The median number of ERCPs performed was 2 (range 1-10). Three of the 35 patients (9%) developed post-ERCP pancreatitis at some point during their treatment. At last follow-up since initial ERCP (median 16 months, range 2.4-184 months), 12 (34%) patients endorsed abdominal pain and 11 (31%) reported experiencing nausea. CONCLUSION: For select patients with abdominal pain in the setting of minimal CBD dilation and no evidence of stone disease or malignancy, ERCP can safely and effectively be used to manage symptoms. While patients may require multiple interventions, they can derive long-term relief from these procedures.

Safety, Efficacy, and Technical Details of Endoscopic Retrograde Cholangiopancreatography After Irreversible Electroporation for Locally Advanced Pancreatic Cancer.

BACKGROUND: Patients undergoing irreversible electroporation (IRE) for locally advanced pancreatic cancer (LAPC) may experience biliary obstruction owing to inflammation generated by tumor ablation. This study assessed the safety, efficacy, and technical details of endoscopic retrograde cholangiopancreatography (ERCP) for biliary decompression after IRE. METHODS: A single-institution database of patients undergoing IRE for LAPC between 2012 and 2017 was queried for patients requiring post-IRE ERCP. Patients were evaluated along demographic, laboratory, procedural, and outcome measures. RESULTS: Of 113 patients with LAPC who underwent IRE, 6 (5.3%) required subsequent ERCP for biliary obstruction. A total of 12 ERCPs were performed. Two patients (33%) had duodenal bulb narrowing requiring dilation, and one patient (17%) had a pancreatic head cyst complicating guidewire passage. Biliary cannulation was achieved in all patients in a median time of 30 min. Four patients (67%) underwent sphincterotomy, and 5 (83%) underwent stent placement. Post-procedurally, all showed liver test improvement. None developed pancreatitis. Four patients underwent a 2nd ERCP. All were successful and included stent placement. CONCLUSIONS: For patients with biliary obstruction after IRE, ERCP with sphincterotomy and stent placement can safely relieve this obstruction. Duodenal dilation and careful guidewire manipulation may be required to maximize technical success in these patients.

Social isolation alters behavior, the gut-immune-brain axis, and neurochemical circuits in male and female prairie voles.

The absence of social support, or social isolation, can be stressful, leading to a suite of physical and psychological health issues. Growing evidence suggests that disruption of the gut-immune-brain axis plays a crucial role in the negative outcomes seen from social isolation stress. However, the mechanisms remain largely unknown. The socially monogamous prairie vole (Microtus ochrogaster) has been validated as a useful model for studying negative effects of social isolation on the brain and behaviors, yet how the gut microbiome and central immune system are altered in isolated prairie voles are still unknown. Here, we utilized this social rodent to examine how social isolation stress alters the gut-immune-brain axis and relevant behaviors. Adult male and female prairie voles (n = 48 per sex) experienced social isolation or were cohoused with a same-sex cagemate (control) for six weeks. Thereafter, their social and anxiety-like behaviors, neuronal circuit activation, neurochemical expression, and microgliosis in key brain regions, as well as gut microbiome alterations from the isolation treatment were examined. Social isolation increased anxiety-like behaviors and impaired social affiliation. Isolation also resulted in sex- and brain region-specific alterations in neuronal activation, neurochemical expression, and microgliosis. Further, social isolation resulted in alterations to the gut microbiome that were correlated with key brain and behavioral measures. Our data suggest that social isolation alters the gut-immune-brain axis in a sex-dependent manner and that gut microbes, central glial cells, and neurochemical systems may play a critical, integrative role in mediating negative outcomes from social isolation.

Role of Long Noncoding RNA Gas5 in Cocaine Action.

BACKGROUND: Long noncoding RNAs (lncRNAs) are a class of transcribed RNA molecules greater than 200 nucleotides in length. Although lncRNAs do not encode proteins, they play numerous functional roles in gene expression regulation. lncRNAs are notably abundant in brain; however, their neural functions remain largely unknown. METHODS: We examined the expression of the lncRNA Gas5 in nucleus accumbens (NAc), a key brain reward region, of adult male mice after cocaine administration. We then performed viral-mediated overexpression of Gas5 in NAc neurons to determine its role in addiction-related behaviors. We also carried out RNA sequencing to investigate Gas5-mediated transcriptomic changes. RESULTS: We demonstrated that repeated short-term or long-term cocaine administration decreased expression of Gas5 in NAc. Viral-mediated overexpression of Gas5 in NAc neurons decreased cocaine-induced conditioned place preference. Likewise, Gas5 overexpression led to decreased cocaine intake, decreased motivation, and compulsive-like behavior to acquire cocaine, and it facilitated extinction of cocaine-seeking behavior. Transcriptome profiling identified numerous Gas5-mediated gene expression changes that are enriched in relevant neural function categories. Interestingly, these Gas5-regulated gene expression changes significantly overlap with chronic cocaine-induced transcriptome alterations, suggesting that Gas5 may serve as an important regulator of transcriptional responses to cocaine. CONCLUSIONS: Altogether, our study demonstrates a novel lncRNA-based molecular mechanism of cocaine action.

Correlation of Biliary Colic in the Absence of Cholelithiasis with Pancreaticobiliary Obstruction.

A small fraction of patients undergoing cholecystectomy for biliary colic are subsequently diagnosed with an obstructive pancreatic head mass. We review our experience with such patients to provide insight into improving evaluation before cholecystectomy. Retrospective chart review of patients undergoing cholecystectomy from 2004 to 2015 identified six patients who underwent laparoscopic cholecystectomy for biliary colic before being diagnosed with a pancreatic head neoplasm within six months after cholecystectomy. Charts were analyzed for presenting symptoms, evaluation before and after cholecystectomy, and operative findings. Patients ranged from 50 to 72 years of age and included five males and one female. None had evidence of cholelithiasis or acute cholecystitis on initial evaluation. Median time from cholecystectomy to diagnosis of pancreatic head mass was two months (range 1-5 months). Two patients eventually underwent pancreaticoduodenectomy. Patients with symptoms of biliary colic in the absence of evidence of cholecystitis or choledochal abnormality should undergo intraoperative cholangiogram at the time of cholecystectomy as well as close clinical follow-up to ensure resolution of symptoms. Abnormalities of either should prompt radiographic evaluation focused on identification of a pancreatic mass causing extrinsic compression of the bile duct.

Understanding Why Undergraduate Students Declare and Continue to Study an Exercise Science-Related Major.

Understanding factors that contribute to a student's selection of an exercise science-related major is important to student success, higher education and industry. This study sought to 1) better understand why undergraduate students study an exercise science-related major, 2) determine whether positive influences to study an exercise science-related major differ by academic classification, and 3) identify what student's aspirations are after graduation. Department administrators from four-year colleges and universities offering an exercise science-related major in the Northwest Region of the United States (i.e., Idaho, Montana, Oregon, and Washington) were contacted. Cooperating department administrators were given self-reported questionnaires for students to complete using a snowball sampling method. A total of 388 participants completed the questionnaire. Interest in the subject and potential job opportunities were the most common reasons to study an exercise science-related major. Self-reported Holland's codes identified that realistic and social personalities were most prevalent among participants. Seniors rated a friend's influence and college advisors as stronger influences to study an exercise science-related major compared to freshmen. Pay in the field was a stronger influence for freshmen to study an exercise science-related major than for fifth-year seniors, whereas freshmen were less influenced by introductory courses to study an exercise-science related major than fifth-year seniors. The majority of undergraduate students studying an exercise science-related major planned on attending graduate school after completing their baccalaureate degree. These findings can be used to help guide undeclared students and better serve undergraduates enrolled in an exercise science-related major.

Tet1 in Nucleus Accumbens Opposes Depression- and Anxiety-Like Behaviors.

Depression is a leading cause of disease burden, yet current therapies fully treat <50% of affected individuals. Increasing evidence implicates epigenetic mechanisms in depression and antidepressant action. Here we examined a possible role for the DNA dioxygenase, ten-eleven translocation protein 1 (TET1), in depression-related behavioral abnormalities. We applied chronic social defeat stress, an ethologically validated mouse model of depression-like behaviors, and examined Tet1 expression changes in nucleus accumbens (NAc), a key brain reward region. We show decreased Tet1 expression in NAc in stress-susceptible mice only. Surprisingly, selective knockout of Tet1 in NAc neurons of adult mice produced antidepressant-like effects in several behavioral assays. To identify Tet1 targets that mediate these actions, we performed RNAseq on NAc after conditional deletion of Tet1 and found that immune-related genes are the most highly dysregulated. Moreover, many of these genes are also upregulated in the NAc of resilient mice after chronic social defeat stress. These findings reveal a novel role for TET1, an enzyme important for DNA hydroxymethylation, in the brain's reward circuitry in modulating stress responses in mice. We also identify a subset of genes that are regulated by TET1 in this circuitry. These findings provide new insight into the pathophysiology of depression, which can aid in future antidepressant drug discovery efforts.

Nucleosome Repositioning: A Novel Mechanism for Nicotine- and Cocaine-Induced Epigenetic Changes.

Drugs of abuse modify behavior by altering gene expression in the brain. Gene expression can be regulated by changes in DNA methylation as well as by histone modifications, which alter chromatin structure, DNA compaction and DNA accessibility. In order to better understand the molecular mechanisms directing drug-induced changes in chromatin structure, we examined DNA-nucleosome interactions within promoter regions of 858 genes in human neuroblastoma cells (SH-SY5Y) exposed to nicotine or cocaine. Widespread, drug- and time-resolved repositioning of nucleosomes was identified at the transcription start site and promoter region of multiple genes. Nicotine and cocaine produced unique and shared changes in terms of the numbers and types of genes affected, as well as repositioning of nucleosomes at sites which could increase or decrease the probability of gene expression based on DNA accessibility. Half of the drug-induced nucleosome positions approximated a theoretical model of nucleosome occupancy based on physical and chemical characteristics of the DNA sequence, whereas the basal or drug naïve positions were generally DNA sequence independent. Thus we suggest that nucleosome repositioning represents an initial dynamic genome-wide alteration of the transcriptional landscape preceding more selective downstream transcriptional reprogramming, which ultimately characterizes the cell- and tissue-specific responses to drugs of abuse.

QTL Mapping and Candidate Gene Analysis of Telomere Length Control Factors in Maize (Zea mays L.).

Telomere length is a quantitative trait important for many cellular functions. Failure to regulate telomere length contributes to genomic instability, cellular senescence, cancer, and apoptosis in humans, but the functional significance of telomere regulation in plants is much less well understood. To gain a better understanding of telomere biology in plants, we used quantitative trait locus (QTL) mapping to identify genetic elements that control telomere length variation in maize (Zea mays L.). For this purpose, we measured the median and mean telomere lengths from 178 recombinant inbred lines of the IBM mapping population and found multiple regions that collectively accounted for 33-38% of the variation in telomere length. Two-way analysis of variance revealed interaction between the quantitative trait loci at genetic bin positions 2.09 and 5.04. Candidate genes within these and other significant QTL intervals, along with select genes known a priori to regulate telomere length, were tested for correlations between expression levels and telomere length in the IBM population and diverse inbred lines by quantitative real-time PCR. A slight but significant positive correlation between expression levels and telomere length was observed for many of the candidate genes, but Ibp2 was a notable exception, showing instead a negative correlation. A rad51-like protein (TEL-MD_5.04) was strongly supported as a candidate gene by several lines of evidence. Our results highlight the value of QTL mapping plus candidate gene expression analysis in a genetically diverse model system for telomere research.