Adaptive Prediction for Social Contexts: The Cerebellar Contribution to Typical and Atypical Social Behaviors.

Social interactions involve processes ranging from face recognition to understanding others' intentions. To guide appropriate behavior in a given context, social interactions rely on accurately predicting the outcomes of one's actions and the thoughts of others. Because social interactions are inherently dynamic, these predictions must be continuously adapted. The neural correlates of social processing have largely focused on emotion, mentalizing, and reward networks, without integration of systems involved in prediction. The cerebellum forms predictive models to calibrate movements and adapt them to changing situations, and cerebellar predictive modeling is thought to extend to nonmotor behaviors. Primary cerebellar dysfunction can produce social deficits, and atypical cerebellar structure and function are reported in autism, which is characterized by social communication challenges and atypical predictive processing. We examine the evidence that cerebellar-mediated predictions and adaptation play important roles in social processes and argue that disruptions in these processes contribute to autism.

Consensus Paper: Cerebellum and Reward.

Cerebellum is a key-structure for the modulation of motor, cognitive, social and affective functions, contributing to automatic behaviours through interactions with the cerebral cortex, basal ganglia and spinal cord. The predictive mechanisms used by the cerebellum cover not only sensorimotor functions but also reward-related tasks. Cerebellar circuits appear to encode temporal difference error and reward prediction error. From a chemical standpoint, cerebellar catecholamines modulate the rate of cerebellar-based cognitive learning, and mediate cerebellar contributions during complex behaviours. Reward processing and its associated emotions are tuned by the cerebellum which operates as a controller of adaptive homeostatic processes based on interoceptive and exteroceptive inputs. Lobules VI-VII/areas of the vermis are candidate regions for the cortico-subcortical signaling pathways associated with loss aversion and reward sensitivity, together with other nodes of the limbic circuitry. There is growing evidence that the cerebellum works as a hub of regional dysconnectivity across all mood states and that mental disorders involve the cerebellar circuitry, including mood and addiction disorders, and impaired eating behaviors where the cerebellum might be involved in longer time scales of prediction as compared to motor operations. Cerebellar patients exhibit aberrant social behaviour, showing aberrant impulsivity/compulsivity. The cerebellum is a master-piece of reward mechanisms, together with the striatum, ventral tegmental area (VTA) and prefrontal cortex (PFC). Critically, studies on reward processing reinforce our view that a fundamental role of the cerebellum is to construct internal models, perform predictions on the impact of future behaviour and compare what is predicted and what actually occurs.

A Critical Period for Development of Cerebellar-Mediated Autism-Relevant Social Behavior.

The cerebellum has been increasingly implicated in autism spectrum disorder (ASD) with many ASD-linked genes impacting both cerebellar function and development. However, the precise timing and critical periods of when abnormal cerebellar neurodevelopment contributes to ASD-relevant behaviors remains poorly understood. In this study, we identify a critical period for the development of ASD-relevant behaviors in a cerebellar male mouse model of tuberous sclerosis complex (TSC), by using the mechanistic target of rapamycin (mTOR) inhibitor, rapamycin, to pharmacologically inhibit dysregulated downstream signaling. We find independent critical periods during which abnormal ASD-relevant behaviors develop for the two core ASD diagnostic criteria, social impairments and behavioral flexibility, and delineate an anatomic, physiological, and behavioral framework. These findings not only further our understanding of the genetic mechanisms underlying the timing of ASD-relevant behaviors but also have the capacity to inform potential therapies to optimize treatment interventions.SIGNIFICANCE STATEMENT No targeted treatments currently exist for autism spectrum disorder (ASD). This complex developmental disorder has established links to genetic and circuit aberrations, yet the precise timing and coordination of these underlying mechanisms that contribute to the spectrum of physiological and behavioral abnormalities remains unclear. Cerebellar pathology is consistently seen in ASD individuals; therefore, we sought to identify the specific windows for cerebellar involvement in the development of ASD-relevant behaviors. Using pharmacologic treatment paradigms, we outline distinct critical periods of developmental vulnerability for ASD-relevant social and inflexible behaviors. From this study, we posit a refined window of time during which ASD symptoms develop that will inform therapeutic timing.

Functional CRISPR and shRNA Screens Identify Involvement of Mitochondrial Electron Transport in the Activation of Evofosfamide.

Evofosfamide (TH-302) is a hypoxia-activated DNA-crosslinking prodrug currently in clinical development for cancer therapy. Oxygen-sensitive activation of evofosfamide depends on one-electron reduction, yet the reductases that catalyze this process in tumors are unknown. We used RNA sequencing, whole-genome CRISPR knockout, and reductase-focused short hairpin RNA screens to interrogate modifiers of evofosfamide activation in cancer cell lines. Involvement of mitochondrial electron transport in the activation of evofosfamide and the related nitroaromatic compounds EF5 and FSL-61 was investigated using 143B ρ 0 (ρ zero) cells devoid of mitochondrial DNA and biochemical assays in UT-SCC-74B cells. The potency of evofosfamide in 30 genetically diverse cancer cell lines correlated with the expression of genes involved in mitochondrial electron transfer. A whole-genome CRISPR screen in KBM-7 cells identified the DNA damage-response factors SLX4IP, C10orf90 (FATS), and SLFN11, in addition to the key regulator of mitochondrial function, YME1L1, and several complex I constituents as modifiers of evofosfamide sensitivity. A reductase-focused shRNA screen in UT-SCC-74B cells similarly identified mitochondrial respiratory chain factors. Surprisingly, 143B ρ 0 cells showed enhanced evofosfamide activation and sensitivity but had global transcriptional changes, including increased expression of nonmitochondrial flavoreductases. In UT-SCC-74B cells, evofosfamide oxidized cytochromes a, b, and c and inhibited respiration at complexes I, II, and IV without quenching reactive oxygen species production. Our results suggest that the mitochondrial electron transport chain contributes to evofosfamide activation and that predicting evofosfamide sensitivity in patients by measuring the expression of canonical bioreductive enzymes such as cytochrome P450 oxidoreductase is likely to be futile.

Osteoid Osteoma in the Thumb of an Adolescent Patient.

Osteoid osteoma is a relatively common benign tumor of bone, typically presenting in the diaphysis of long bones during the second or third decades of life. This tumor is rarely reported in the hand and wrist, making up only approximately 10% of cases. When reported in the hand, osteoid osteoma tends to occur more frequently in the proximal phalanx of the index and middle fingers. We present the case of an osteoid osteoma in an adolescent male in the distal phalanx of the thumb. The presentation of this osteoid osteoma was atypical owing to its location and lack of characteristic clinical features, making the initial work-up and final diagnosis challenging and pointing to the importance of considering this diagnosis on a differential for painful bony tumors in the hand.

Autistic-like behaviour and cerebellar dysfunction in Purkinje cell Tsc1 mutant mice.

Autism spectrum disorders (ASDs) are highly prevalent neurodevelopmental disorders, but the underlying pathogenesis remains poorly understood. Recent studies have implicated the cerebellum in these disorders, with post-mortem studies in ASD patients showing cerebellar Purkinje cell (PC) loss, and isolated cerebellar injury has been associated with a higher incidence of ASDs. However, the extent of cerebellar contribution to the pathogenesis of ASDs remains unclear. Tuberous sclerosis complex (TSC) is a genetic disorder with high rates of comorbid ASDs that result from mutation of either TSC1 or TSC2, whose protein products dimerize and negatively regulate mammalian target of rapamycin (mTOR) signalling. TSC is an intriguing model to investigate the cerebellar contribution to the underlying pathogenesis of ASDs, as recent studies in TSC patients demonstrate cerebellar pathology and correlate cerebellar pathology with increased ASD symptomatology. Functional imaging also shows that TSC patients with ASDs display hypermetabolism in deep cerebellar structures, compared to TSC patients without ASDs. However, the roles of Tsc1 and the sequelae of Tsc1 dysfunction in the cerebellum have not been investigated so far. Here we show that both heterozygous and homozygous loss of Tsc1 in mouse cerebellar PCs results in autistic-like behaviours, including abnormal social interaction, repetitive behaviour and vocalizations, in addition to decreased PC excitability. Treatment of mutant mice with the mTOR inhibitor, rapamycin, prevented the pathological and behavioural deficits. These findings demonstrate new roles for Tsc1 in PC function and define a molecular basis for a cerebellar contribution to cognitive disorders such as autism.

Neuronal Tsc1/2 complex controls autophagy through AMPK-dependent regulation of ULK1.

Tuberous sclerosis complex (TSC) is a disorder arising from mutation in the TSC1 or TSC2 gene, characterized by the development of hamartomas in various organs and neurological manifestations including epilepsy, intellectual disability and autism. TSC1/2 protein complex negatively regulates the mammalian target of rapamycin complex 1 (mTORC1) a master regulator of protein synthesis, cell growth and autophagy. Autophagy is a cellular quality-control process that sequesters cytosolic material in double membrane vesicles called autophagosomes and degrades it in autolysosomes. Previous studies in dividing cells have shown that mTORC1 blocks autophagy through inhibition of Unc-51-like-kinase1/2 (ULK1/2). Despite the fact that autophagy plays critical roles in neuronal homeostasis, little is known on the regulation of autophagy in neurons. Here we show that unlike in non-neuronal cells, Tsc2-deficient neurons have increased autolysosome accumulation and autophagic flux despite mTORC1-dependent inhibition of ULK1. Our data demonstrate that loss of Tsc2 results in autophagic activity via AMPK-dependent activation of ULK1. Thus, in Tsc2-knockdown neurons AMPK activation is the dominant regulator of autophagy. Notably, increased AMPK activity and autophagy activation are also found in the brains of Tsc1-conditional mouse models and in cortical tubers resected from TSC patients. Together, our findings indicate that neuronal Tsc1/2 complex activity is required for the coordinated regulation of autophagy by AMPK. By uncovering the autophagy dysfunction associated with Tsc2 loss in neurons, our work sheds light on a previously uncharacterized cellular mechanism that contributes to altered neuronal homeostasis in TSC disease.

Chromosome conformation maps in fission yeast reveal cell cycle dependent sub nuclear structure.

Successful progression through the cell cycle requires spatial and temporal regulation of gene transcript levels and the number, positions and condensation levels of chromosomes. Here we present a high resolution survey of genome interactions in Schizosaccharomyces pombe using synchronized cells to investigate cell cycle dependent changes in genome organization and transcription. Cell cycle dependent interactions were captured between and within S. pombe chromosomes. Known features of genome organization (e.g. the clustering of telomeres and retrotransposon long terminal repeats (LTRs)) were observed throughout the cell cycle. There were clear correlations between transcript levels and chromosomal interactions between genes, consistent with a role for interactions in transcriptional regulation at specific stages of the cell cycle. In silico reconstructions of the chromosome organization within the S. pombe nuclei were made by polymer modeling. These models suggest that groups of genes with high and low, or differentially regulated transcript levels have preferred positions within the S. pombe nucleus. We conclude that the S. pombe nucleus is spatially divided into functional sub-nuclear domains that correlate with gene activity. The observation that chromosomal interactions are maintained even when chromosomes are fully condensed in M phase implicates genome organization in epigenetic inheritance and bookmarking.

Copy number variation plays an important role in clinical epilepsy.

OBJECTIVE: To evaluate the role of copy number abnormalities detectable using chromosomal microarray (CMA) testing in patients with epilepsy at a tertiary care center. METHODS: We identified patients with International Classification of Diseases, ninth revision (ICD-9) codes for epilepsy or seizures and clinical CMA testing performed between October 2006 and February 2011 at Boston Children's Hospital. We reviewed medical records and included patients who met criteria for epilepsy. We phenotypically characterized patients with epilepsy-associated abnormalities on CMA. RESULTS: Of 973 patients who had CMA and ICD-9 codes for epilepsy or seizures, 805 patients satisfied criteria for epilepsy. We observed 437 copy number variants (CNVs) in 323 patients (1-4 per patient), including 185 (42%) deletions and 252 (58%) duplications. Forty (9%) were confirmed de novo, 186 (43%) were inherited, and parental data were unavailable for 211 (48%). Excluding full chromosome trisomies, CNV size ranged from 18kb to 142Mb, and 34% were >500kb. In at least 40 cases (5%), the epilepsy phenotype was explained by a CNV, including 29 patients with epilepsy-associated syndromes and 11 with likely disease-associated CNVs involving epilepsy genes or "hotspots." We observed numerous recurrent CNVs including 10 involving loss or gain of Xp22.31, a region described in patients with and without epilepsy. INTERPRETATION: Copy number abnormalities play an important role in patients with epilepsy. Because the diagnostic yield of CMA for epilepsy patients is similar to the yield in autism spectrum disorders and in prenatal diagnosis, for which published guidelines recommend testing with CMA, we recommend the implementation of CMA in the evaluation of unexplained epilepsy.

Ultrafast evolution and loss of CRISPRs following a host shift in a novel wildlife pathogen, Mycoplasma gallisepticum.

Measureable rates of genome evolution are well documented in human pathogens but are less well understood in bacterial pathogens in the wild, particularly during and after host switches. Mycoplasma gallisepticum (MG) is a pathogenic bacterium that has evolved predominantly in poultry and recently jumped to wild house finches (Carpodacus mexicanus), a common North American songbird. For the first time we characterize the genome and measure rates of genome evolution in House Finch isolates of MG, as well as in poultry outgroups. Using whole-genome sequences of 12 House Finch isolates across a 13-year serial sample and an additional four newly sequenced poultry strains, we estimate a nucleotide diversity in House Finch isolates of only ∼2% of ancestral poultry strains and a nucleotide substitution rate of 0.8-1.2×10(-5) per site per year both in poultry and in House Finches, an exceptionally fast rate rivaling some of the highest estimates reported thus far for bacteria. We also found high diversity and complete turnover of CRISPR arrays in poultry MG strains prior to the switch to the House Finch host, but after the invasion of House Finches there is progressive loss of CRISPR repeat diversity, and recruitment of novel CRISPR repeats ceases. Recent (2007) House Finch MG strains retain only ∼50% of the CRISPR repertoire founding (1994-95) strains and have lost the CRISPR-associated genes required for CRISPR function. Our results suggest that genome evolution in bacterial pathogens of wild birds can be extremely rapid and in this case is accompanied by apparent functional loss of CRISPRs.

Graded loss of tuberin in an allelic series of brain models of TSC correlates with survival, and biochemical, histological and behavioral features.

Tuberous sclerosis complex (TSC) is a neurodevelopmental disorder with prominent brain manifestations due to mutations in either TSC1 or TSC2. Here, we describe novel mouse brain models of TSC generated using conditional hypomorphic and null alleles of Tsc2 combined with the neuron-specific synapsin I cre (SynIcre) allele. This allelic series of homozygous conditional hypomorphic alleles (Tsc2(c-del3/c-del3)SynICre(+)) and heterozygote null/conditional hypomorphic alleles (Tsc2(k/c-del3)SynICre(+)) achieves a graded reduction in expression of Tsc2 in neurons in vivo. The mice demonstrate a progressive neurologic phenotype including hunchback, hind limb clasp, reduced survival and brain and cortical neuron enlargement that correlates with a graded reduction in expression of Tsc2 in the two sets of mice. Both models also showed behavioral abnormalities in anxiety, social interaction and learning assays, which correlated with Tsc2 protein levels as well. The observations demonstrate that there are graded biochemical, cellular and clinical/behavioral effects that are proportional to the extent of reduction in Tsc2 expression in neurons. Further, they suggest that some patients with milder manifestations of TSC may be due to persistent low-level expression of functional protein from their mutant allele. In addition, they point to the potential clinical benefit of strategies to raise TSC2 protein expression from the wild-type allele by even modest amounts.

Pyrosequencing reveals regional differences in fruit-associated fungal communities.

We know relatively little of the distribution of microbial communities generally. Significant work has examined a range of bacterial communities, but the distribution of microbial eukaryotes is less well characterized. Humans have an ancient association with grape vines (Vitis vinifera) and have been making wine since the dawn of civilization, and fungi drive this natural process. While the molecular biology of certain fungi naturally associated with vines and wines is well characterized, complementary investigations into the ecology of fungi associated with fruiting plants is largely lacking. DNA sequencing technologies allow the direct estimation of microbial diversity from a given sample, avoiding culture-based biases. Here, we use deep community pyrosequencing approaches, targeted at the 26S rRNA gene, to examine the richness and composition of fungal communities associated with grapevines and test for geographical community structure among four major regions in New Zealand (NZ). We find over 200 taxa using this approach, which is 10-fold more than previously recovered using culture-based methods. Our analyses allow us to reject the null hypothesis of homogeneity in fungal species richness and community composition across NZ and reveal significant differences between major areas.

Insights into the role of JAK2-I724T variant in myeloproliferative neoplasms from a unique cohort of New Zealand patients.

OBJECTIVES: This study aimed to compile bioinformatic and experimental information for JAK2 missense variants previously reported in myeloproliferative neoplasms (MPN) and determine if germline JAK2-I724T, recently found to be common in New Zealand Polynesians, associates with MPN. METHODS: For all JAK2 variants found in the literature, gnomAD_exome allele frequencies were extracted and REVEL scores were calculated using the dbNSFP database. We investigated the prevalence of JAK2-I724T in a cohort of 111 New Zealand MPN patients using a TaqMan assay, examined its allelic co-occurrence with JAK2-V617F using Oxford Nanopore sequencing, and modelled the impact of I724T on JAK2 using I-Mutant and ChimeraX software. RESULTS: Several non-V617F JAK2 variants previously reported in MPN had REVEL scores greater than 0.5, suggesting pathogenicity. JAK2-I724T (REVEL score 0.753) was more common in New Zealand Polynesian MPN patients (n = 2/27; 7.4%) than in other New Zealand patients (n = 0/84; 0%) but less common than expected for healthy Polynesians (n = 56/377; 14.9%). Patients carrying I724T (n = 2), one with polycythaemia vera and one with essential thrombocythaemia, had high-risk MPN. Both patients with JAK2-I724T were also positive for JAK2-V617F, found on the same allele as I724T, as well as separately. In silico modelling did not identify noticeable structural changes that would give JAK2-I724T a gain-of-function. CONCLUSION: Several non-canonical JAK2 variants with high REVEL scores have been reported in MPN, highlighting the need to further understand their relationship with disease. The JAK2-I724T variant does not drive MPN, but additional investigations are required to exclude any potential modulatory effect on the MPN phenotype.

Operative challenges in management of concurrent interrupted aortic arch and descending thoracic aortic aneurysm.

Interrupted aortic arch is a rare finding in the adult patient. This condition in combination with a descending thoracic aortic aneurysm is an even more exceptional occurrence. Surgical management includes open, endovascular, and hybrid options. We present the case of a 57-year-old man with interrupted aortic arch and concomitant descending thoracic aortic aneurysm, review characterization of this entity, and discuss management options with consideration to associated risks.

Prenatal rapamycin results in early and late behavioral abnormalities in wildtype C57BL/6 mice.

Mammalian target of rapamycin (mTOR) signaling has been shown to be deregulated in a number of genetic, neurodevelopmental disorders including Tuberous Sclerosis Complex, Neurofibromatosis, Fragile X, and Rett syndromes. As a result, mTOR inhibitors, such as rapamycin and its analogs, offer potential therapeutic avenues for these disorders. Some of these disorders-such as Tuberous Sclerosis Complex-can be diagnosed prenatally. Thus, prenatal administration of these inhibitors could potentially prevent the development of the devastating symptoms associated with these disorders. To assess the possible detrimental effects of prenatal rapamycin treatment, we evaluated both early and late behavioral effects of a single rapamycin treatment at embryonic day 16.5 in wildtype C57Bl/6 mice. This treatment adversely impacted early developmental milestones as well as motor function in adult animals. Rapamycin also resulted in anxiety-like behaviors during both early development and adulthood but did not affect adult social behaviors. Together, these results indicate that a single, prenatal rapamycin treatment not only adversely affects early postnatal development but also results in long lasting negative effects, persisting into adulthood. These findings are of importance in considering prenatal administration of rapamycin and related drugs in the treatment of patients with neurogenetic, neurodevelopmental disorders.

A Case of Multivessel Coronary Artery Disease and Anomalous Origin of the Right Coronary Artery With a Malignant Course Presenting With Non-exertional Chest Discomfort and Brugada Phenocopy.

Coronary artery anomalies (CAAs) are an uncommon cause of chest pain in the younger population. Misdiagnosis can be detrimental and lead to sudden cardiac deaths. We present a 62-year-old male with a past medical history significant for chest pain history with a workup in 2001 presumed to be non-cardiac in origin from bronchial asthma. He presented from a Micronesian Island for the evaluation of non-exertional chest discomfort. Further workup showed a Brugada type I pattern on ECG and ST wave depressions on anterolateral and inferior leads with associated AVR elevation on exercise stress testing. Further ischemic workup with coronary angiography revealed right dominant circulation with three-vessel coronary artery disease (CAD), including mid-left anterior descending (LAD) artery chronic total occlusion (CTO) with the right to left collaterals, left circumflex, and right coronary artery (RCA) with the accompanied anomalous origin of RCA. The patient underwent surgical correction of the anomalous RCA and coronary artery bypass grafting for the multi-vessel CAD. CAAs are usually found incidentally during ischemic workups similar to this case. Patients with CAAs can be managed conservatively with caution regarding physical activity. However, high-risk patients will warrant surgical treatment to avoid sudden cardiac death. The diagnosis of CAAs can be challenging and prone to misdiagnosis and maltreatment. It may be beneficial to pursue this in younger patients with ischemia-like symptoms. Further studies should be performed to identify the true incidence and guide medical practitioners regarding the risks, costs, and benefits of diagnosing and surgically treating CAAs in the general population.

Penetrating cardiac injury: a narrative review.

Background and Objective: Penetrating cardiac trauma is rare but can cause life-threatening complications. Survival is dependent on prompt diagnosis and treatment. Given the low incidence and life-threatening implications, it is difficult to study in large prospective studies. The current literature regarding penetrating cardiac trauma comes primarily from large, experienced trauma centers and military sources. Understanding the history, current literature and even expert opinion can help with effectively treating injury promptly to maximize survival after penetrating cardiac trauma. We aimed to review the etiology and history of penetrating cardiac trauma. We review the prehospital treatment and initial diagnostic modalities. We review the incisional approaches to treatment including anterolateral thoracotomy, median sternotomy and subxiphoid window. The repair of atrial, ventricular and coronary injuries are also addressed in our review. The purpose of this paper is to perform a narrative review to better describe the history, etiology, presentation, and management of penetrating cardiac trauma. Methods: A narrative review was preformed synthesizing literature from MEDLINE and bibliographic review from identified publications. Studies were included based on relevance without exclusion to time of publication or original publication language. Key Content and Findings: Sonographic identification of pericardial fluid can aid in diagnosis of patients too unstable for CT. Anterolateral thoracotomy should be used for emergent repairs and initial stabilization. A median sternotomy can be used for more stable patients with known injuries. Carefully placed mattress sutures can be useful for repair of injuries surrounding coronary vessels to avoid devascularization. Conclusions: Penetrating cardiac trauma is life threatening and requires prompt workup and treatment. Trauma algorithms should continue to refine and be clear on which patients should undergo an emergency department (ED) thoracotomy, median sternotomy and further imaging.

Impact of More Detailed Measures of Disease Severity on Racial Disparities in Cardiac Surgery Mortality among Native Hawaiians and Pacific Islanders.

Studies that examine racial disparities in health outcomes often include analyses that account or adjust for baseline differences in co-morbid conditions. Often, these conditions are defined as dichotomous (Yes/No) variables, and few analyses include clinical and/or laboratory data that could allow for more nuanced estimates of disease severity. However, disease severity - not just prevalence - can differ substantially by race and is an underappreciated mechanism for health disparities. Thus, relying on dichotomous disease indicators may not fully describe health disparities. This study explores the effect of substituting continuous clinical and/or laboratory data for dichotomous disease indicators on racial disparities, using data from the Queen's Medical Center's (QMC) cardiac surgery database (a subset of the national Society of Thoracic Surgeon's cardiothoracic surgery database) as an example case. Two logistic regression models predicting in-hospital mortality were constructed: (I) a baseline model including race and dichotomous (Yes/No) indicators of disease (diabetes, heart failure, liver disease, kidney disease), and (II) a more detailed model with continuous laboratory values in place of the dichotomous indicators (eg, including Hemoglobin A1c level rather than just diabetes yes/no). When only dichotomous disease indicators were used in the model, Native Hawaiian and other Pacific Islander (NHPI) race was significantly associated with in-hospital mortality (OR: 1.57[1.29,2.47], P=.04). Yet when the more specific laboratory values were included, NHPI race was no longer associated with in-hospital mortality (OR: 1.67[0.92,2.28], P=.28). Thus, researchers should be thoughtful in their choice of independent variables and understand the potential impact of how clinical measures are operationalized in their research.