Citations

Habitual reward‐seeking behavior is a hallmark of addictive behaviors. Although habitual behavior could be reversed to goal‐directed behavior, this shifting is not well studied. Here, we identify a role of astrocyte activation in the dorsomedial striatum (DMS) on transition from habitual to goal‐directed reward‐seeking behavior. Utilizing the Inscopix endomicroscopy/fiber photometry in vivo calcium imaging and the cell‐type specific activation of designer receptors exclusively activated by designer drugs (DREADDs), we confirmed that GFAP‐driven activation of hM3Dq DREADDs increases intensity and frequency of calcium signaling in the DMS astrocytes of ALDH1L1‐GCaMP6s expressing mice. We found that this chemogenetic activation of the DMS astrocytes increase and decrease neuronal excitability of direct pathway Medium Spiny Neurons (dMSNs) and indirect pathway Medium Spiny Neurons (iMSNs), respectively. Specifically, it reduced the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in the dMSNs, whereas it increased the amplitude of the sEPSCs and decreased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in the iMSNs. The changes in synaptic events induced by astrocytic activation were significantly inhibited by either of the pretreatments of DPCPX (Adenosine A1R antagonist, 1 μM), PSB12379 (Inhibitor of ectonucleotidase, CD73, 10 μM), NBTI [Inhibitor of the astrocytic adenosine transporter, equilibrative nucleoside transporter 1 (ENT1, slc29a1), 10 μM], and genetic deletion of ENT1. These data suggest that astrocytic activation‐induced synaptic activities are, in part, adenosine‐dependent. In the evaluation tests of goal‐directed and habitual reward‐seeking, the chemogenetic activation of the DMS astrocytes shifted the habitual behavior to goal‐directed action in sucrose reward‐seeking for WT, but not ENT1 KO mice. The astrocytic activation‐induced shifting was rescued when ENT1 expression was normalized in the DMS astrocytes of the ENT1 KO mice. On the other hand, when mice were trained to have goal‐directed behavior, the astrocytic activation in the DMS did not change the reward‐seeking behavioral pattern. Together, our results indicate that astrocyte‐regulated adenosine signaling in the DMS determines goal‐directed and habitual behaviors by selectively regulating synapses in the MSNs. The interaction between astrocytes and neurons via adenosine signaling could be a potential therapeutic target for maladaptive reward‐seeking behaviors. Support or Funding Information This work was supported by the Samuel C. Johnson for Genomics of Addiction Program at Mayo Clinic, the Ulm Foundation, and National Institute on Alcohol Abuse and Alcoholism (K01 AA027773 to SK, R01 AA018779 to DSC).

Abstract p90 Ribosomal S6 Kinase 2 (p90RSK2) is a substrate of ERK and plays an active role in anti-apoptosis signaling and cell cycle regulation. Our proteomics studies revealed that p90RSK2 is not only activated but also tyrosine-phosphorylated in hematopoietic cells expressing constitutively activated leukemogenic FGFR3 mutants. FGFR3 is a receptor-tyrosine kinase that responds to fibroblast growth factor (FGF). Recent studies have suggested that FGFR3 may play a significant role in the pathogenesis and disease progression of some hematopoietic malignancies including t(4;14)(p16.3;q32.3) multiple myeloma, which is associated with dysregulation of FGFR3. We found that the MEK1 inhibitor U0126 effectively inhibited RSK2 activation induced by FGFR3, suggesting that FGFR3 activates RSK2 through the MEK/ERK pathway. Interestingly, FGFR3-dependent tyrosine phosphorylation at Y529 was required for phosphorylation and activation of the Ser/Thr kinase RSK2 by ERK. By using a specific phospho-RSK2 (Y529) antibody, we identified FGFR3 as the direct tyrosine kinase that phosphorylates RSK2 at Y529 in an in vitro kinase assay, which only contains purified recombinant active FGFR3 and RSK2 proteins. Substitution of Y529 in RSK2 attenuates inactive ERK binding to RSK2, which is prior to and required for ERK-dependent phosphorylation and activation of RSK2. In addition, reconstitution of RSK2 phosphorylation at Y529 consequently enhanced inactive ERK binding by a GST pull down, suggesting that phosphorylation at Y529 by FGFR3 facilitates ERK binding to RSK2, which is a sequential event and precedes inactive ERK binding. These observations support a novel two-step model that FGFR3 activates RSK2 by both assisting inactive ERK binding via tyrosine phosphorylation of RSK2 at Y529 and activating the MEK/ERK pathway. Moreover, we observed that RSK2 is specifically phosphorylated at Y529 and activated in FGFR3 expressing various human t(4;14) positive MM cell lines. Targeted down-regulation of RSK2 by siRNA induced significant apoptosis in FGFR3-expressing human myeloma cell lines including OPM1 and KMS11. In addition, a specific RSK inhibitor fmk induced significant apoptosis in t(4;14) positive human myeloma cells including KMS11, OPM1, LP1 and KMS18, but not in control t(4;14) negative myeloma cell lines including ANBL6 and U266. Similar results were obtained by using another RSK specific and potent inhibitor BI-D1870. Furthermore, we observed that fmk induced significant apoptosis in primary CD138-positive, FGFR3-expressing myeloma cells from a t(4;14) positive multiple myeloma patient, but not in the control CD138-negative cells from the same patient, nor primary samples from a t(4;14)-negative patient as a control. Together, these data not only support our model that RSK2 is a critical signaling effector of FGFR3 in hematopoietic transformation, but also provide “proof of principle” for the therapeutic potential of RSK2 inhibitors such as fmk in treatment of t(4;14) positive, FGFR3-expressing multiple myeloma with minimal non-specific cytotoxicity.

IL-4/CCL24–mediated interaction with eosinophils maintains dermis-resident macrophages as replicative niches for Leishmania major .

Background The absence of appropriate and timely critical care in resource-limited countries like Vietnam contributes to poor outcomes and excessive mortality in the acutely ill, pediatric population. Often, tertiary care is limited to major urban centers and patients from remote locations face lengthy travel. How these distances impact care-seeking behavior of the patients’ caregiver, patient acuity on admission, and hospitalization outcome in critically ill children remains unknown. Methods We assessed 471 pediatric patients admitted to intensive care units (ICUs) from the emergency department in a pediatric referral center in Hanoi that serves northern Vietnam. Demographic information from caregivers and medical information was collected by trained staff on site and from the medical record. Patient outcome was followed for sixty days in the ICUs. We analyzed associations between patient admission acuity and outcome to socio-geographic and-demographic data using bivariate logistic regression and log-rank analyses. Results The median child’s age in our study was 1.8 months, with the majority under 1 year (83.3%). On admission to the ICU, 40.5% of patients required life-saving treatment. Within sixty days of admission, 73.3% of patients were discharged, 21.8% experienced extended admission and 3.08% expired in the ICU. Patient and caretaker’s distance from home residence to Vietnam National Children’s Hospital (VNCH) greater than 60 kilometers was significantly associated with a more severe patient acuity on ICU admission (Odds Ratio, OR=2.01, 95% Confidence Limit, CL=1.33, 3.06), an extended admission or expiration in the ICU (OR=1.94, 95% CL=1.15, 3.20), a lower family income (OR=3.74, 95% CL=2.46, 5.64), lack of caregiver college education (OR=3.73, 95% CL=2.34, 6.05), and greater referrals and days delayed seeking care. Conclusions These findings highlight numerous barriers facing acutely ill children and their caretakers, who must travel long distances to reach appropriate critical care at a tertiary referral hospital. Research into current protocols, skills, and staffing at lower facilities and public health education in these regions is needed to determine the best avenues for improvement of critical care services beyond tertiary centers.

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 369 nominally genome-wide significant loci ( P < 5 × 10 −8 ) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 360 loci for which replication data were available, 241 loci influencing surface area and 66 influencing thickness remained significant after replication, with 237 loci passing multiple testing correction ( P < 8.3 × 10 −10 ; 187 influencing surface area and 50 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation ( r G = −0.32, SE = 0.05, P = 6.5 × 10 −12 ), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 46 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function. Identifying genetic influences on human cortical structure. ( A ) Measurement of cortical surface area and thickness from MRI. ( B ) Genomic locations of common genetic variants that influence global and regional cortical structure. ( C ) Our results support the radial unit hypothesis that the expansion of cortical surface area is driven by proliferating neural progenitor cells. ( D ) Cortical surface area shows genetic correlation with psychiatric and cognitive traits. Error bars indicate SE. IMAGE CREDITS: (A) K. COURTNEY; (C) M. R. GLASS

9009 Background: Programmed death-1 (PD-1) is an inhibitory T-cell co-receptor that may lead to suppression of antitumor immunity. Lambrolizumab is a humanized monoclonal IgG4 antibody against PD-1. This study explored the safety and clinical activity of lambrolizumab in patients (pts) with advanced melanoma (MEL). Methods: In this ongoing phase 1b expansion study of MEL pts with or without previous ipilimumab (IPI) treatment, lambrolizumab was administered IV every 2 or 3 weeks until disease progression or unacceptable toxicity. Tumor response was assessed every 12 weeks by independent, central, blinded radiographic review per immune-related response criteria and RECIST 1.1. Results: As of December 1, 2012, 294 pts with MEL were enrolled, including 179 IPI-naive and 115 IPI-pretreated. Pts received lambrolizumab 10 mg/kg (n = 183) or 2 mg/kg (n = 111). Preliminary data from the first 85 consecutive pts dosed before April 25, 2012, who had independent radiologic review available as of December 3, 2012, indicate a confirmed overall response rate per RECIST 1.1 of greater than 35%, pooled across all doses and schedules and including both IPI-naive and IPI-pretreated patients. The median duration of response has not been reached as only 2 pts who had initial response discontinued due to disease progression, but the duration of confirmed responses range from 28+ to 240+ days (up to 8+ months). Among 133 pts who were dosed with lambrolizumab before July 31, 2012, and evaluable for adverse events (AEs) as of September 28, 2012, fatigue (22%), rash (18%), and pruritus (14%) were the most common drug-related AEs (mostly grade 1/2). The incidence of drug-related grade 3/4 AEs was 10% (24% regardless of attribution). Four drug-related cases of pneumonitis were reported, all of grade 1/2. Grade 3/4 drug-related hypothyroidism (n = 1) and hyperthyroidism (n = 1) were noted. Conclusions: Preliminary data suggest that lambrolizumab has significant antitumor activity and is well tolerated with manageable side effects in both IPI-naive and IPI-pretreated MEL pts. These data have led to an ongoing, international, randomized study of lambrolizumab versus chemotherapy in IPI-pretreated MEL. Clinical trial information: NCT01295827.

Abstract Pathogenic fibrotic diseases, including idiopathic pulmonary fibrosis (IPF), have some of the worst prognoses and affect millions of people worldwide. With unclear etiology and minimally effective therapies, two‐thirds of IPF patients die within 2‐5 years from this progressive interstitial lung disease. Transforming Growth Factor Beta (TGFβ) and insulin‐like growth factor‐1 (IGF‐1) are known to promote fibrosis; however, myofibroblast specific upregulation of IGF‐1 in the initiation and progression of TGFβ‐induced fibrogenesis and IPF have remained unexplored. To address this, the current study (1) documents the upregulation of IGF‐1 via TGFβ in myofibroblasts and fibrotic lung tissue, as well as its correlation with decreased pulmonary function in advanced IPF; (2) identifies IGF‐1's C1 promoter as mediating the increase in IGF‐1 transcription by TGFβ in pulmonary fibroblasts; (3) determines that SMAD2 and mTOR signaling are required for TGFβ‐dependent Igf‐1 expression in myofibroblasts; (4) demonstrates IGF‐1R activation is essential to support TGFβ‐driven profibrotic myofibroblast functions and excessive wound healing; and (5) establishes the effectiveness of slowing the progression of murine lung fibrosis with the IGF‐1R inhibitor OSI‐906. These findings expand our knowledge of IGF‐1's role as a novel fibrotic‐switch, bringing us one step closer to understanding the complex biological mechanisms responsible for fibrotic diseases and developing effective therapies.

TPS468 Background: Trastuzumab (T), a monoclonal antibody (mAb) targeting HER2, is standard of care palliative 1st-line therapy for advanced HER2+ GEJ/GC patients (pts). M, an Fc-engineered anti-HER2 mAb, targets the same HER2 epitope but with higher affinity for both 158V (high binding) and 158F (low binding) alleles of activating Fc receptor CD16A. M coordinately enhanced both innate and adaptive immunity, including antigen-specific T-cell responses to HER2. PD-1 and LAG-3 are T-cell checkpoint molecules that suppress T-cell function. MGA012 (INCMGA00012) is a humanized, hinge-stabilized, IgG4 κ anti-PD-1 mAb blocking binding of PD-L1 or PD-L2 to PD-1. MGD013 is a humanized Fc-bearing bispecific tetravalent protein that binds to both PD-1 and LAG-3, inhibiting their respective ligand binding. We previously reported that a CTX-free regimen of M+PD-1 blockade was well tolerated in GEJ/GC pts, and induced a 30% objective response rate (ORR). This was 2- to 3-fold greater than in historical controls with checkpoint inhibitors alone. This registration-directed trial assesses efficacy, safety, and tolerability of M+checkpoint inhibition ± CTX in metastatic/locally advanced, treatment-naïve, HER2+ GEJ/GC pts. Methods: This is a 2-cohort, adaptive open-label phase 2/3 study. The first single arm, CTX-free cohort A evaluates M+MGA012 in HER2+ (immunohistochemistry [IHC] 3+) and PD-L1+ (excluding microsatellite instability high) pts. After 40 pts are evaluated for response/safety, 60 more pts will be enrolled if the threshold for continuation is met. In randomized cohort B, HER2+ (IHC 3+ or 2+/fluorescent in situ hybridization+) pts are enrolled irrespective of PD-L1 status. Part 1 randomizes pts to 1 of 4 arms (50 pts each): control arm (T+CTX) or 1 experimental arm (M+CTX; M+CTX+MGA012; M+CTX+MGD013). CTX is investigator’s choice XELOX or mFOLFOX-6. Part 2 consists of control (T+CTX) vs 1 experimental arm (M+CTX) + either MGA012 or MGD013, depending on results from part 1; with 250 pts each. The primary efficacy endpoint for cohort A (both parts) is ORR per RECIST 1.1; for cohort B part 2 it is overall survival.

Machine learning (ML) utilizes artificial intelligence to generate predictive models efficiently and more effectively than conventional methods through detection of hidden patterns within large data sets. With this in mind, there are several areas within hepatology where these methods can be applied. In this review, we examine the literature pertaining to machine learning in hepatology and liver transplant medicine. We provide an overview of the strengths and limitations of ML tools and their potential applications to both clinical and molecular data in hepatology. ML has been applied to various types of data in liver disease research, including clinical, demographic, molecular, radiological, and pathological data. We anticipate that use of ML tools to generate predictive algorithms will change the face of clinical practice in hepatology and transplantation. This review will provide readers with the opportunity to learn about the ML tools available and potential applications to questions of interest in hepatology.